609 files changed, 3749 insertions, 86580 deletions

diff --git a/_A_Textbook_Of_Engineering_Physics/Chapter11.ipynb b/A_Textbook_Of_Engineering_Physics/Chapter11.ipynb
index 2ca36fdf..2ca36fdf 100755
--- a/_A_Textbook_Of_Engineering_Physics/Chapter11.ipynb
+++ b/A_Textbook_Of_Engineering_Physics/Chapter11.ipynb
diff --git a/_A_Textbook_Of_Engineering_Physics/Chapter11_1.ipynb b/A_Textbook_Of_Engineering_Physics/Chapter11_1.ipynb
index 2ca36fdf..2ca36fdf 100755
--- a/_A_Textbook_Of_Engineering_Physics/Chapter11_1.ipynb
+++ b/A_Textbook_Of_Engineering_Physics/Chapter11_1.ipynb
diff --git a/_A_Textbook_Of_Engineering_Physics/Chapter12.ipynb b/A_Textbook_Of_Engineering_Physics/Chapter12.ipynb
index 7ced75e1..7ced75e1 100755
--- a/_A_Textbook_Of_Engineering_Physics/Chapter12.ipynb
+++ b/A_Textbook_Of_Engineering_Physics/Chapter12.ipynb
diff --git a/_A_Textbook_Of_Engineering_Physics/Chapter12_1.ipynb b/A_Textbook_Of_Engineering_Physics/Chapter12_1.ipynb
index 7ced75e1..7ced75e1 100755
--- a/_A_Textbook_Of_Engineering_Physics/Chapter12_1.ipynb
+++ b/A_Textbook_Of_Engineering_Physics/Chapter12_1.ipynb
diff --git a/_A_Textbook_Of_Engineering_Physics/Chapter13.ipynb b/A_Textbook_Of_Engineering_Physics/Chapter13.ipynb
index 2e8d2e4e..2e8d2e4e 100755
--- a/_A_Textbook_Of_Engineering_Physics/Chapter13.ipynb
+++ b/A_Textbook_Of_Engineering_Physics/Chapter13.ipynb
diff --git a/_A_Textbook_Of_Engineering_Physics/Chapter13_1.ipynb b/A_Textbook_Of_Engineering_Physics/Chapter13_1.ipynb
index 2e8d2e4e..2e8d2e4e 100755
--- a/_A_Textbook_Of_Engineering_Physics/Chapter13_1.ipynb
+++ b/A_Textbook_Of_Engineering_Physics/Chapter13_1.ipynb
diff --git a/_A_Textbook_Of_Engineering_Physics/Chapter14.ipynb b/A_Textbook_Of_Engineering_Physics/Chapter14.ipynb
index 1a941a59..1a941a59 100755
--- a/_A_Textbook_Of_Engineering_Physics/Chapter14.ipynb
+++ b/A_Textbook_Of_Engineering_Physics/Chapter14.ipynb
diff --git a/_A_Textbook_Of_Engineering_Physics/Chapter14_1.ipynb b/A_Textbook_Of_Engineering_Physics/Chapter14_1.ipynb
index 1a941a59..1a941a59 100755
--- a/_A_Textbook_Of_Engineering_Physics/Chapter14_1.ipynb
+++ b/A_Textbook_Of_Engineering_Physics/Chapter14_1.ipynb
diff --git a/_A_Textbook_Of_Engineering_Physics/Chapter15.ipynb b/A_Textbook_Of_Engineering_Physics/Chapter15.ipynb
index fd70c5b8..fd70c5b8 100755
--- a/_A_Textbook_Of_Engineering_Physics/Chapter15.ipynb
+++ b/A_Textbook_Of_Engineering_Physics/Chapter15.ipynb
diff --git a/_A_Textbook_Of_Engineering_Physics/Chapter15_1.ipynb b/A_Textbook_Of_Engineering_Physics/Chapter15_1.ipynb
index 42c1e8e6..42c1e8e6 100755
--- a/_A_Textbook_Of_Engineering_Physics/Chapter15_1.ipynb
+++ b/A_Textbook_Of_Engineering_Physics/Chapter15_1.ipynb
diff --git a/_A_Textbook_Of_Engineering_Physics/Chapter16.ipynb b/A_Textbook_Of_Engineering_Physics/Chapter16.ipynb
index 0852b1be..0852b1be 100755
--- a/_A_Textbook_Of_Engineering_Physics/Chapter16.ipynb
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diff --git a/_A_Textbook_Of_Engineering_Physics/Chapter16_1.ipynb b/A_Textbook_Of_Engineering_Physics/Chapter16_1.ipynb
index 0852b1be..0852b1be 100755
--- a/_A_Textbook_Of_Engineering_Physics/Chapter16_1.ipynb
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diff --git a/_A_Textbook_Of_Engineering_Physics/Chapter17.ipynb b/A_Textbook_Of_Engineering_Physics/Chapter17.ipynb
index 24b8e0d7..24b8e0d7 100755
--- a/_A_Textbook_Of_Engineering_Physics/Chapter17.ipynb
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diff --git a/_A_Textbook_Of_Engineering_Physics/Chapter17_1.ipynb b/A_Textbook_Of_Engineering_Physics/Chapter17_1.ipynb
index 24b8e0d7..24b8e0d7 100755
--- a/_A_Textbook_Of_Engineering_Physics/Chapter17_1.ipynb
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diff --git a/_A_Textbook_Of_Engineering_Physics/Chapter18.ipynb b/A_Textbook_Of_Engineering_Physics/Chapter18.ipynb
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--- a/_A_Textbook_Of_Engineering_Physics/Chapter18.ipynb
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diff --git a/_A_Textbook_Of_Engineering_Physics/Chapter18_1.ipynb b/A_Textbook_Of_Engineering_Physics/Chapter18_1.ipynb
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diff --git a/_A_Textbook_Of_Engineering_Physics/Chapter19.ipynb b/A_Textbook_Of_Engineering_Physics/Chapter19.ipynb
index 9cd6b0d3..9cd6b0d3 100755
--- a/_A_Textbook_Of_Engineering_Physics/Chapter19.ipynb
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diff --git a/_A_Textbook_Of_Engineering_Physics/Chapter19_1.ipynb b/A_Textbook_Of_Engineering_Physics/Chapter19_1.ipynb
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diff --git a/_A_Textbook_Of_Engineering_Physics/Chapter21.ipynb b/A_Textbook_Of_Engineering_Physics/Chapter21.ipynb
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diff --git a/_A_Textbook_Of_Engineering_Physics/Chapter21_1.ipynb b/A_Textbook_Of_Engineering_Physics/Chapter21_1.ipynb
index 4528f908..4528f908 100755
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diff --git a/_A_Textbook_Of_Engineering_Physics/Chapter22.ipynb b/A_Textbook_Of_Engineering_Physics/Chapter22.ipynb
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diff --git a/_A_Textbook_Of_Engineering_Physics/Chapter22_1.ipynb b/A_Textbook_Of_Engineering_Physics/Chapter22_1.ipynb
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diff --git a/_A_Textbook_Of_Engineering_Physics/Chapter23.ipynb b/A_Textbook_Of_Engineering_Physics/Chapter23.ipynb
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diff --git a/_A_Textbook_Of_Engineering_Physics/Chapter23_1.ipynb b/A_Textbook_Of_Engineering_Physics/Chapter23_1.ipynb
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diff --git a/_A_Textbook_Of_Engineering_Physics/Chapter24.ipynb b/A_Textbook_Of_Engineering_Physics/Chapter24.ipynb
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diff --git a/_A_Textbook_Of_Engineering_Physics/Chapter24_1.ipynb b/A_Textbook_Of_Engineering_Physics/Chapter24_1.ipynb
index 67066c07..67066c07 100755
--- a/_A_Textbook_Of_Engineering_Physics/Chapter24_1.ipynb
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diff --git a/_A_Textbook_Of_Engineering_Physics/Chapter4.ipynb b/A_Textbook_Of_Engineering_Physics/Chapter4.ipynb
index 024db2ff..024db2ff 100755
--- a/_A_Textbook_Of_Engineering_Physics/Chapter4.ipynb
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diff --git a/_A_Textbook_Of_Engineering_Physics/Chapter4_1.ipynb b/A_Textbook_Of_Engineering_Physics/Chapter4_1.ipynb
index 024db2ff..024db2ff 100755
--- a/_A_Textbook_Of_Engineering_Physics/Chapter4_1.ipynb
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diff --git a/_A_Textbook_Of_Engineering_Physics/Chapter5.ipynb b/A_Textbook_Of_Engineering_Physics/Chapter5.ipynb
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--- a/_A_Textbook_Of_Engineering_Physics/Chapter5.ipynb
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diff --git a/_A_Textbook_Of_Engineering_Physics/Chapter5_1.ipynb b/A_Textbook_Of_Engineering_Physics/Chapter5_1.ipynb
index f4389219..f4389219 100755
--- a/_A_Textbook_Of_Engineering_Physics/Chapter5_1.ipynb
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diff --git a/_A_Textbook_Of_Engineering_Physics/Chapter6.ipynb b/A_Textbook_Of_Engineering_Physics/Chapter6.ipynb
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--- a/_A_Textbook_Of_Engineering_Physics/Chapter6_1.ipynb
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diff --git a/_A_Textbook_Of_Engineering_Physics/Chapter7.ipynb b/A_Textbook_Of_Engineering_Physics/Chapter7.ipynb
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--- a/_A_Textbook_Of_Engineering_Physics/Chapter7.ipynb
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diff --git a/_A_Textbook_Of_Engineering_Physics/Chapter7_1.ipynb b/A_Textbook_Of_Engineering_Physics/Chapter7_1.ipynb
index 1db562d5..1db562d5 100755
--- a/_A_Textbook_Of_Engineering_Physics/Chapter7_1.ipynb
+++ b/A_Textbook_Of_Engineering_Physics/Chapter7_1.ipynb
diff --git a/_A_Textbook_Of_Engineering_Physics/Chapter8.ipynb b/A_Textbook_Of_Engineering_Physics/Chapter8.ipynb
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--- a/_A_Textbook_Of_Engineering_Physics/Chapter8.ipynb
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diff --git a/_A_Textbook_Of_Engineering_Physics/Chapter8_1.ipynb b/A_Textbook_Of_Engineering_Physics/Chapter8_1.ipynb
index ff6879b2..ff6879b2 100755
--- a/_A_Textbook_Of_Engineering_Physics/Chapter8_1.ipynb
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diff --git a/_A_Textbook_Of_Engineering_Physics/README.txt b/A_Textbook_Of_Engineering_Physics/README.txt
index e156a531..e156a531 100755
--- a/_A_Textbook_Of_Engineering_Physics/README.txt
+++ b/A_Textbook_Of_Engineering_Physics/README.txt
diff --git a/_A_Textbook_Of_Engineering_Physics/screenshots/Chapter11.png b/A_Textbook_Of_Engineering_Physics/screenshots/Chapter11.png
index d60291ea..d60291ea 100755
--- a/_A_Textbook_Of_Engineering_Physics/screenshots/Chapter11.png
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diff --git a/_A_Textbook_Of_Engineering_Physics/screenshots/Chapter11_1.png b/A_Textbook_Of_Engineering_Physics/screenshots/Chapter11_1.png
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--- a/_A_Textbook_Of_Engineering_Physics/screenshots/Chapter11_1.png
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diff --git a/_A_Textbook_Of_Engineering_Physics/screenshots/Chapter12.png b/A_Textbook_Of_Engineering_Physics/screenshots/Chapter12.png
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--- a/_A_Textbook_Of_Engineering_Physics/screenshots/Chapter12.png
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--- a/_A_Textbook_Of_Engineering_Physics/screenshots/Chapter13_1.png
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diff --git a/About_Mumbai_by_sd/hemla.ipynb b/About_Mumbai_by_sd/hemla.ipynb
deleted file mode 100644
index 5cea9cb6..00000000
--- a/About_Mumbai_by_sd/hemla.ipynb
+++ /dev/null
@@ -1,778 +0,0 @@
-{
- "metadata": {
-  "name": "",
-  "signature": "sha256:9826abe74c775578903ec0e922c705aacf445defe2dc3badb10ce4727f434663"
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter2-Compressible Flow with Friction and Heat: A Review"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Ex1-pg19"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "#what is the gas constant of air and density of air\n",
-      "import math\n",
-      "#intilization variable\n",
-      "p=3*10**6 ; #pressure in Pa\n",
-      "t=298. ; #temperatue in kelvin\n",
-      "mw= 29.; #molecular weight in kg/mol\n",
-      "ru=8314.; #universal constant in J/kmol.K\n",
-      "r=ru/mw ;\n",
-      "#using perfect gas law to get density:\n",
-      "rho=p/(r*t) ;\n",
-      "print'%s %.2f %s'%('Gas constant of air in',r,'J/kg.K')\n",
-      "print'%s %.1f %s'%('Density of air in',rho,'kg/m^3')"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Gas constant of air in 286.69 J/kg.K\n",
-        "Density of air in 35.1 kg/m^3\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Ex2-pg23"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "#find out the exit temperature and exit density by various methods \n",
-      "import math\n",
-      "t1=288.; #inlet temperture in Kelvin\n",
-      "p1=100*10**3; #inlet pressure in Pa\n",
-      "p2=1*10**6 #exit pressure in Pa\n",
-      "gma=1.4; #gamma.\n",
-      "rg=287.; #gas constant in J/kg.K\n",
-      "t2=t1*(p2/p1)**((gma-1)/gma);   #exit temperature \n",
-      "print'%s %.5f %s'%('Exit temperature in',t2,'K')\n",
-      "#first method to find exit density:\n",
-      "#application of perfect gas law at exit\n",
-      "rho=p2/(rg*t2); #rho= exit density.\n",
-      "print'%s %.7f %s'%('exit density at by method 1 in',rho,'kg/m^3')\n",
-      "#method 2: using isentropic relation between inlet and exit density.\n",
-      "rho1=p1/(rg*t1); #inlet density.\n",
-      "rho=rho1*(p2/p1)**(1/gma);\n",
-      "print'%s %.2f %s'%('exit density by method 2 in',rho,'kg/m^3')\n",
-      "\n",
-      "                                                     "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Exit temperature in 556.04095 K\n",
-        "exit density at by method 1 in 6.2663021 kg/m^3\n",
-        "exit density by method 2 in 6.27 kg/m^3\n"
-       ]
-      }
-     ],
-     "prompt_number": 2
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Ex3-pg25"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "#what is the rate of mass flow through exit \n",
-      "import math\n",
-      "d1=1.2 #inlet 1 density in kg/m^3.\n",
-      "u1=25. # inlet 1 veocity in m/s.\n",
-      "a1=0.25 #inlet 1 area in m^2.\n",
-      "d2=0.2 #inlet 2 density in kg/m^3.\n",
-      "u2=225. #inlet 2 velocity in m/s.\n",
-      "a2=0.10 #inlet 2 area in m^2.\n",
-      "m1=d1*a1*u1; #rate of mass flow entering inlet 1.\n",
-      "m2=d2*u2*a2; #rate of mass flow entering inlet 2.\n",
-      "#since total mass in=total mass out,\n",
-      "m3=m1+m2; #m3=rate of mass flow through exit.\n",
-      "print'%s %.f %s'%('Rate of mass flow through exit in',m3,' kg/s')\n",
-      "\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Rate of mass flow through exit in 12  kg/s\n"
-       ]
-      }
-     ],
-     "prompt_number": 4
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Ex4-pg27"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "#what is the axial force needed to support the plate and lateral force needed to support the plate\n",
-      "import math\n",
-      "u1=2 #speed of water going on the plate. X-component in m/s.\n",
-      "v1=0 #speed of water going on the plate. Y-component in m/s.\n",
-      "u2=1 #speed of water going on the plate. X-component in m/s.\n",
-      "v2=1.73 #speed of water going on the plate Y-coponent in m/s.\n",
-      "m=0.1 #rate of flow of mass of the water on the plate in kg/s.\n",
-      "#Using Newton's second law.\n",
-      "Fx=m*(u2-u1); #X-component of force exerted by water\n",
-      "print'%s %.1f %s'%('Axial force needed to support the plate in',Fx,'N')\n",
-      "Fy=m*(v2-v1); #Y-component of force exerted by water.\n",
-      "print'%s %.3f %s'%('Lateral force needed to support the plate in',Fy,'N')\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Axial force needed to support the plate in -0.1 N\n",
-        "Lateral force needed to support the plate in 0.173 N\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Ex5-pg29"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "#calculate the Exit total and static temperature \n",
-      "m=50 #mass flow rate in kg/s.\n",
-      "T1=298 #inlet temperature in K.\n",
-      "u1=150 #inlet velocity in m/s.\n",
-      "cp1=1004 #specific heat at constant pressure of inlet in J/kg.K.\n",
-      "gm=1.4 #gamma.\n",
-      "u2=400 # exit velocity in m/s.\n",
-      "cp2=1243. #specific heat at constant pressure of exit in J/kg.K.\n",
-      "q=42*10**6 #heat transfer rate in control volume in Watt.\n",
-      "me=-100*10**3 #mechanical power in Watt.\n",
-      "#first calculate total enthalpy at the inlet:\n",
-      "ht1=cp1*T1+(u1**2)/2; #ht1=Total inlet enthalpy.\n",
-      "#now applying conservation of energy equation:\n",
-      "ht2=ht1+((q-me)/m) #ht2=Total enthalpy at exit.\n",
-      "Tt2=ht2/cp2; #Tt2=Total exit temperature.\n",
-      "T2=Tt2-((u2**2)/(2*cp2)); #T2=static exit temperature.\n",
-      "print'%s %.5f %s'%('Exit total temperature in',Tt2,'K')\n",
-      "print'%s %.4f %s'%('Exit static temperature in',T2,'K')"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Exit total temperature in 927.14562 K\n",
-        "Exit static temperature in 862.7852 K\n"
-       ]
-      }
-     ],
-     "prompt_number": 6
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Ex6-pg65"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "#intilization variable\n",
-      "import math\n",
-      "d=0.2 #Diameter in meters.\n",
-      "M1=0.2 #inlet Mach no.\n",
-      "p1=100*10**3 #inlet pressure in Pa\n",
-      "Tt1=288. #total inlet temperature in K\n",
-      "q=100*10**3 #rate of heat transfer to fluid in Watt.\n",
-      "rg=287. #Gas constant in J/kg.K.\n",
-      "gm=1.4 #gamma\n",
-      "#(a)inlet mass flow:\n",
-      "m=((gm/rg)**(1./2.))*(p1/(Tt1)**(1./2.))*3.14*(d*d)/4.*(M1/(1.+((gm-1.)/2.)*(M1**2.))**((gm+1.)/(2.*(gm-1.))));\n",
-      "\n",
-      "#(b)\n",
-      "qm=q/m; #Heat per unit mass.\n",
-      "#Tt1/Tcr=0.1736, pt1/Pcr=1.2346, ((Delta(s)/R)1=6.3402,p1/Pcr=2.2727)\n",
-      "Tcr=Tt1/0.1736;\n",
-      "\n",
-      "Pcr=p1/2.2727;\n",
-      "#From energy equation:\n",
-      "cp=(gm/(gm-1.))*rg;\n",
-      "Tt2=Tt1+(q/cp);\n",
-      "q1cr=cp*(Tcr-Tt1)/1000.;\n",
-      "M2=0.22;\n",
-      "#From table : pt2/Pcr=1.2281, (Delta(s)/R)2=5.7395, p2/Pcr=2.2477.\n",
-      "#The percent total pressure drop is (((pt1/Pcr)-(pt2/Pcr))/(pt1/Pcr))*100.\n",
-      "p2=2.2477*Pcr;\n",
-      "dp=((1.2346-1.2281)/1.2346)*100;\n",
-      "#Entropy rise is the difference between (delta(s)/R)1 and (delta(s)/R)2.\n",
-      "ds=6.3402-5.7395;\n",
-      "#Static pressure drop in duct due to heat transfer is\n",
-      "dps=((p1/Pcr)-(p2/Pcr))*Pcr/1000.;\n",
-      "print'%s %.7f %s'%('Mass flow rate through duct in',m,'kg/s')\n",
-      "print'%s %.4f %s'%('Critical heat flux that would choke the duct for the M1 in',q1cr,'kJ/kg')\n",
-      "print'%s %.2f %s'%('The exit Mach No.',M2,'')\n",
-      "print'%s %.7f %s'%('The percent total pressure loss',dp,'%')\n",
-      "print'%s %.4f %s'%('The entropy rise',ds,'')\n",
-      "print'%s %.7f %s'%('The static pressure drop in ',dps,'kPa')"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Mass flow rate through duct in 2.5235091 kg/s\n",
-        "Critical heat flux that would choke the duct for the M1 in 1377.1556 kJ/kg\n",
-        "The exit Mach No. 0.22 \n",
-        "The percent total pressure loss 0.5264863 %\n",
-        "The entropy rise 0.6007 \n",
-        "The static pressure drop in  1.1000132 kPa\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Ex7-pg67"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "#what is total exit temperautre if exit is choked and maximum heat released and fule to air ratio to thermally choke the combustor exit and total pressure loss\n",
-      "#intilization variable\n",
-      "import math\n",
-      "M1=3.0 ##Mach no. at inlet\n",
-      "pt1=45*10**3 ##Total pressure t inlet in Pa\n",
-      "Tt1=1800 ##Total temperature at inlet in K\n",
-      "hv=12000 ##Lower heating value of hydrogen kJ/kg\n",
-      "gm=1.3 ##gamma\n",
-      "R=0.287 ##in kJ/kg.K\n",
-      "##Using RAYLEIGH table for M1=3.0 and gamma=1.3, we get Tt1/Tcr=0.6032, pt1/Pcr=4.0073.\n",
-      "Tcr=Tt1/0.6032\n",
-      "Pcr=pt1/4.0073\n",
-      "##if exit is choked, Tt2=Tcr\n",
-      "Tt2=Tt1/0.6032;\n",
-      "cp=gm*R/(gm-1);\n",
-      "##Energy balance across burner:\n",
-      "Q1cr=cp*(Tcr-Tt1);\n",
-      "f=(Q1cr/120000);\n",
-      "##total pressure loss:\n",
-      "dpt=1-Pcr/pt1;\n",
-      "print'%s %.4f %s'%('Total exit temperature if exit is choked in',Tt2,'K')\n",
-      "print'%s %.4f %s'%('Maximum heat released per unit mass of air in',Q1cr, 'kJ/kg')\n",
-      "print'%s %.7f %s'%('fuel-to-air ratio to thermally choke the combustor exit',f,'')\n",
-      "print'%s %.7f %s'%('Total pressure loss (in fraction)',dpt,'')\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Total exit temperature if exit is choked in 2984.0849 K\n",
-        "Maximum heat released per unit mass of air in 1472.6069 kJ/kg\n",
-        "fuel-to-air ratio to thermally choke the combustor exit 0.0122717 \n",
-        "Total pressure loss (in fraction) 0.7504554 \n"
-       ]
-      }
-     ],
-     "prompt_number": 8
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Ex8-pg67"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "#calculate the new inlet mach no and spilled flow at the inlet\n",
-      "#initilization variable \n",
-      "import math\n",
-      "Tt1=50.+460. ##Converting the inlet temp. to the absolute scale i.e. in degree R\n",
-      "M1=0.5 ##Initial inlet Mach no.\n",
-      "pt1=14.7 ##Units in psia\n",
-      "gm=1.4 ##gamma\n",
-      "R=53.34 ##units in ft.lbf/lbm.degree R\n",
-      "Tcr=Tt1/0.69136 \n",
-      "cp=gm*R/(gm-1)\n",
-      "##using energy equation:\n",
-      "Q1cr=cp*(Tcr-Tt1)\n",
-      "##since heat flux is 1.2(Q1cr).\n",
-      "q=1.2*Q1cr\n",
-      "Tt1cr1=Tt1+(Q1cr/cp) ##new exit total temp.\n",
-      "z=Tt1/Tt1cr1\n",
-      "M2=0.473\n",
-      "\n",
-      "f=M1/(1+((gm-1)/2)*M1**2)**((gm+1)/(2*(gm-1)))\n",
-      "\n",
-      "sm=((f*(M1)-f*(M2))/f*(M1))*100. ##sm=The % spilled flow at the inlet\n",
-      "print'%s %.5f %s'%('The new inlet Mach no.',M2,'')\n",
-      "print'%s %.5f %s'%('The % spilled flow at the inlet',sm,'')\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The new inlet Mach no. 0.47300 \n",
-        "The % spilled flow at the inlet 1.35000 \n"
-       ]
-      }
-     ],
-     "prompt_number": 9
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Ex9-pg76"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "#intilization variable\n",
-      "#calculate choking length abd exit mach no and total pressure loss and the static pressure and impulse due to friction \n",
-      "import math\n",
-      "d=0.2 ##diameter in meters.\n",
-      "l=0.2 ##length in meters.\n",
-      "Cf=0.005 ##average wall friction coefficient.\n",
-      "M1=0.24 ##inlet mach no.\n",
-      "gm=1.4 ##gamma.\n",
-      "##From FANNO tbale\n",
-      "L1cr=(9.3866*d/2)/(4*Cf);\n",
-      "L2cr=L1cr-l;\n",
-      "##from FANNO table\n",
-      "M2=0.3;\n",
-      "x=2.4956;\n",
-      "y=2.0351;\n",
-      "a=4.5383;\n",
-      "b=3.6191;\n",
-      "i1=2.043;\n",
-      "i2=1.698;\n",
-      "##% total pressure drop due to friction:\n",
-      "dpt=(x-y)/(x)*100;\n",
-      "##static pressur drop:\n",
-      "dps=(a-b)/a*100;\n",
-      "##Loss pf fluid:\n",
-      "lf=(i2-i1);\n",
-      "print'%s %.3f %s'%('The choking length of duct in',L1cr,'m')\n",
-      "print'%s %.1f %s'%('The exit Mach no.',M2,'')\n",
-      "print'%s %.6f %s'%('% total pressure loss',dpt,'')\n",
-      "print'%s %.5f %s'%('The static pressure drop in',dps,'%')\n",
-      "print'%s %.3f %s'%('Loss of impulse due to friction(I* times)',lf,'')\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The choking length of duct in 46.933 m\n",
-        "The exit Mach no. 0.3 \n",
-        "% total pressure loss 18.452476 \n",
-        "The static pressure drop in 20.25428 %\n",
-        "Loss of impulse due to friction(I* times) -0.345 \n"
-       ]
-      }
-     ],
-     "prompt_number": 10
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Ex10-pg77"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "#initilization variable\n",
-      "import math \n",
-      "#caluclate maximum length of the duct that will support given in inlet condition and the new inlet condition and flow drop \n",
-      "M1=0.5\n",
-      "a=2. ## area of cross section units in cm^2\n",
-      "Cf=0.005 ##coefficient of skin friction\n",
-      "gm=1.4 ##gamma\n",
-      "##Calculations\n",
-      "c=2.*(2.+1.); ##Parameter of surface.\n",
-      "##From FANNO table: 4*Cf*L1cr/Dh=1.0691;\n",
-      "Dh=4.*a/c; ##Hydrolic diameter.\n",
-      "L1cr=1.069*Dh/(4.*Cf);\n",
-      "##maximum length will be L1cr.\n",
-      "##For new length(i.e. 2.16*L1cr), Mach no. M2 from FANNO table, M2=0.4;.\n",
-      "M2=0.4;\n",
-      "##the inlet total pressue and temp remains the same, therefore the mass flow rate in the duct is proportional to f(M):\n",
-      "\n",
-      "f=0.5/(1.+((gm-1.)/2.)*0.5**2.)**((gm+1.)/(2.*(gm-1.)))\n",
-      "#endfunction\n",
-      "dm=(f*(M1)-f*(M2))/f*(M1)*100.+10;\n",
-      "print'%s %.3f %s'%(\"(a)Maximum length of duct that will support given inlet condition(in cm):\",L1cr,\"\")\n",
-      "print'%s %.3f %s'%(\"(b)The new inlet condition mach no. M2:\",M2,\"\")\n",
-      "print'%s %.3f %s'%(\"(c)% inlet mass flow drop due to the longer length of the duct:\",dm,\"\")\n",
-      "\n",
-      "\n",
-      "\n",
-      "\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "(a)Maximum length of duct that will support given inlet condition(in cm): 71.267 \n",
-        "(b)The new inlet condition mach no. M2: 0.400 \n",
-        "(c)% inlet mass flow drop due to the longer length of the duct: 15.000 \n"
-       ]
-      }
-     ],
-     "prompt_number": 11
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Ex11-pg78"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "import numpy\n",
-      "M1=0.7;\n",
-      "dpt=0.99; ##pt2/pt1=dpt.\n",
-      "gm=1.4; ##gamma\n",
-      "A2=1.237 \n",
-      "a=1/1.237;\n",
-      "import warnings\n",
-      "warnings.filterwarnings('ignore')\n",
-      "##Calculations:\n",
-      "\n",
-      "k=(1./dpt)*(a)*(M1/(1.+(0.2*(M1)**2.))**3.);\n",
-      "po=([k*0.008,0,k*.12,0,k*.6,-1,k])\n",
-      "W=numpy.roots(po)\n",
-      "i=0;\n",
-      "s=1;\n",
-      "M2=W[4]\n",
-      "print -M2,\"(a)The exit Mach no. M2:\"\n",
-      "\n",
-      "\n",
-      "##p=p2/p1 i.e. static pressure ratio\n",
-      "p=dpt*((1.+(gm-1.)*(M1)**2./2.)/(1.+(gm-1.)*(M2)**2./2.))**(gm/(gm-1.))\n",
-      "##disp(p)\n",
-      "Cpr=(2./(gm*(M1)**2.))*(p-1.) ##Cpr is static pressure recovery : (p2-p1)/q1.\n",
-      "print\"%s %.2f %s\"%(\"(b)The static pressure recovery in the diffuser:\",-Cpr,\"\")\n",
-      "##Change in fluid impulse:\n",
-      "##Fxwalls=I2-I1=A1p1(1+gm*M1**2)-A2p2(1+gm*M2**2)\n",
-      "##Let, u=Fxwall/(p1*A1)\n",
-      "u=1.+gm*(M1)**2.-(1.237)*(p)*(1.+(gm*(M2)**2.))\n",
-      "print\"%s %.2f %s\"%(\"(c)The force acting on the diffuser inner wall nondimensionalized by inlet static pressure and area:\",-u,\"\")\n",
-      "\n",
-      "\n",
-      "\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "(-1.70274823568-0j) (a)The exit Mach no. M2:\n",
-        "(b)The static pressure recovery in the diffuser: 2.11 \n",
-        "(c)The force acting on the diffuser inner wall nondimensionalized by inlet static pressure and area: 0.05 \n"
-       ]
-      }
-     ],
-     "prompt_number": 2
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Ex13-pg85"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "print \"Example2.13\"\n",
-      "import numpy\n",
-      "M1=0.5 #inlet mach no.\n",
-      "p=10. #(p=pt1/p0) whaere pt1 is inlet total pressure and p0 is ambient pressure.\n",
-      "dpc=0.01 #dpc=(pt1-Pth)/pt1 i.e. total pressure loss in convergant section\n",
-      "f=0.99 #f=Pth/pt1\n",
-      "dpd=0.02 #dpd=(Pth-pt2)/Pth i.e. total pressure loss in the divergent section\n",
-      "j=1/0.98 #j=Pth/pt2\n",
-      "A=2. #a=A2/Ath. nozzle area expansion ratio.\n",
-      "gm=1.4 # gamma\n",
-      "R=287. #J/kg.K universal gas constant.\n",
-      "#Calculations:\n",
-      "#\"th\"\" subscript denotes throat.\n",
-      "Mth=1. #mach no at thorat is always 1.\n",
-      "\n",
-      "k=(j)*(1./A)*(Mth/(1+(0.2*(Mth)**2))**3)\n",
-      "po=([k*0.008,0,k*.12,0,k*.6,-1,k])\n",
-      "W=numpy.roots(po)\n",
-      "i=0;\n",
-      "s=1;\n",
-      "M2=W[4]\n",
-      "print M2,\"(a)The exit Mach no. M2:\"\n",
-      "#p2/pt2=1/(1+(gm-1)/2*M2**2)**(gm/(gm-1)) \n",
-      "#pt2=(pt2/Pth)*(Pth/pt1)*(pt1/p0)*p0\n",
-      "#let pr=p2/p0\n",
-      "pr=((1/j)*f*p)/(1+(0.2*(M2)**2))**(gm/(gm-1))\n",
-      "\n",
-      "print pr,\"(b)The exit static pressure in terms of ambient pressure p2/p0:\"#Fxwall=-Fxliquid=I1-I2\n",
-      "\n",
-      "#let r=A1/Ath\n",
-      "r=(f)*(1/M1)*(((1+((gm-1)/2)*(M1)**2)/((gm+1)/2))**((gm+1)/(2*(gm-1))))\n",
-      "#disp(r)\n",
-      "#Psth is throat static pressure.\n",
-      "#z1=Psth/pt1=f/((gm+1)/2)**(gm/(gm-1))\n",
-      "z1=f/((gm+1)/2)**(gm/(gm-1))\n",
-      "#disp(z1)\n",
-      "#p1 is static pressure at inlet\n",
-      "#s1=p1/pt1\n",
-      "s1=1/(1+((gm-1)/2)*(M1)**2)**(gm/(gm-1))\n",
-      "#disp(s1)\n",
-      "#let y=Fxcwall/(Ath*pt1), where Fxwall is Fx converging-wall\n",
-      "y=s1*r*(1+(gm*(M1)**2))-(z1*(1+(gm*(Mth)**2)))\n",
-      "print y,\"(c)The nondimensional axial force acting on the convergent nozzle:\"\n",
-      "#similarly finding nondimensional force on the nozzle DIVERGENT section\n",
-      "#y1=Fxdiv-wall/Ath*pt1\n",
-      "#f1=p2/pt1\n",
-      "f1=pr*(1/p)\n",
-      "#disp(f1)\n",
-      "y1=z1*(1+(gm*(Mth)**2))-f1*A*(1+(gm*(M2)**2))\n",
-      "print y1,\"(d)The nondimensional axial force acting on the divergent nozzle:\"\n",
-      "#total axial force acting on nozzle wall: Fsum=y+y1\n",
-      "Fsum=y+y1\n",
-      "print Fsum,\"(e)The total axial force(nondimensional) acting on the nozzle: \""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Example2.13\n",
-        "(2.17433864456+0j) (a)The exit Mach no. M2:\n",
-        "(0.944524245306+0j) (b)The exit static pressure in terms of ambient pressure p2/p0:\n",
-        "0.254397897726 (c)The nondimensional axial force acting on the convergent nozzle:\n",
-        "(-0.184039795857+0j) (d)The nondimensional axial force acting on the divergent nozzle:\n",
-        "(0.070358101869+0j) (e)The total axial force(nondimensional) acting on the nozzle: \n"
-       ]
-      }
-     ],
-     "prompt_number": 13
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Ex14-pg87"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "#calculate non dimensional axial force and negative sign on the axial force experienced by the compressor \n",
-      "p=20. ##p=p2/p1 i.e. compression ratio.\n",
-      "gm=1.4 ## gamma\n",
-      "##Vx1=Vx2 i.e. axial velocity remains same.\n",
-      "##calculations:\n",
-      "d=p**(1/gm) ##d=d2/d1 i.e. density ratio\n",
-      "A=1./d ## A=A2/A1 i.e. area ratio which is related to density ratio as: A2/A1=d1/d2.\n",
-      "##disp(A)\n",
-      "Fx=1.-p*A  ##Fx=Fxwall/p1*A1 i.e nondimensional axial force.\n",
-      "print'%s %.7f %s'%(\"The non-dimensional axial force is :\",Fx,\"\")\n",
-      "print'%s %.f %s'%(\"The negative sign on the axial force experienced by the compressor structure signifies a thrust production by this component.\",Fx,\" \")"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The non-dimensional axial force is : -1.3535469 \n",
-        "The negative sign on the axial force experienced by the compressor structure signifies a thrust production by this component. -1  \n"
-       ]
-      }
-     ],
-     "prompt_number": 14
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Ex15-pg88"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "print(\"Example 2.15\")\n",
-      "t=1.8 ##t=T2/T1\n",
-      "d=1./t ##d=d2/d1 i.e. density ratio\n",
-      "v=1./d ##v=Vx2/Vx1 axial velocity ratio\n",
-      "ndaf=1.-(v) ##nondimensional axial force acting on the combustor walls\n",
-      "print'%s %.1f %s'%(\"The nondimensional axial force acting on the combustor walls:\",ndaf,\"\")\n",
-      "print(\"Negative sign signifies a thrust production by the device\")\n",
-      "\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Example 2.15\n",
-        "The nondimensional axial force acting on the combustor walls: -0.8 \n",
-        "Negative sign signifies a thrust production by the device\n"
-       ]
-      }
-     ],
-     "prompt_number": 15
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Ex16-pg89"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "print(\"Example 2.16\")\n",
-      "t=0.79 ##T2/T1 i.e. turbione expansion\n",
-      "gm=1.4 ##gamma\n",
-      "##calculations:\n",
-      "d=t**(1./(gm-1.))\n",
-      "##print'%s %.1f %s'%(d)\n",
-      "a=1./d ##area ratio\n",
-      "p=d**gm ##pressure ratio\n",
-      "ndaf=1.-p*a\n",
-      "print'%s %.2f %s'%(\"The nondimensional axial force:\",ndaf,\"\")"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Example 2.16\n",
-        "The nondimensional axial force: 0.21 \n"
-       ]
-      }
-     ],
-     "prompt_number": 16
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/About_Mumbai_by_sd/screenshots/warning.png b/About_Mumbai_by_sd/screenshots/warning.png
deleted file mode 100644
index 81a93724..00000000
--- a/About_Mumbai_by_sd/screenshots/warning.png
+++ /dev/null
diff --git a/About_Mumbai_by_sd/screenshots/warning_1.png b/About_Mumbai_by_sd/screenshots/warning_1.png
deleted file mode 100644
index 81a93724..00000000
--- a/About_Mumbai_by_sd/screenshots/warning_1.png
+++ /dev/null
diff --git a/About_Mumbai_by_sd/screenshots/warning_2.png b/About_Mumbai_by_sd/screenshots/warning_2.png
deleted file mode 100644
index 81a93724..00000000
--- a/About_Mumbai_by_sd/screenshots/warning_2.png
+++ /dev/null
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index fc89b13e..fc89b13e 100755
--- a/_Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/CHapter_17_Homogeneous_Chemical_Reactions.ipynb
+++ b/Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/CHapter_17_Homogeneous_Chemical_Reactions.ipynb
diff --git a/_Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/CHapter_17_Homogeneous_Chemical_Reactions_1.ipynb b/Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/CHapter_17_Homogeneous_Chemical_Reactions_1.ipynb
index f1d1cc5f..f1d1cc5f 100755
--- a/_Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/CHapter_17_Homogeneous_Chemical_Reactions_1.ipynb
+++ b/Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/CHapter_17_Homogeneous_Chemical_Reactions_1.ipynb
diff --git a/_Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_10_Absorbption.ipynb b/Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_10_Absorbption.ipynb
index b131e247..b131e247 100755
--- a/_Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_10_Absorbption.ipynb
+++ b/Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_10_Absorbption.ipynb
diff --git a/_Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_10_Absorption.ipynb b/Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_10_Absorption.ipynb
index f8eab018..f8eab018 100755
--- a/_Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_10_Absorption.ipynb
+++ b/Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_10_Absorption.ipynb
diff --git a/_Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_11_Mass_Transfer_in_Biology_and_Medicine.ipynb b/Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_11_Mass_Transfer_in_Biology_and_Medicine.ipynb
index e0bd3fa9..e0bd3fa9 100755
--- a/_Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_11_Mass_Transfer_in_Biology_and_Medicine.ipynb
+++ b/Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_11_Mass_Transfer_in_Biology_and_Medicine.ipynb
diff --git a/_Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_11_Mass_Transfer_in_Biology_and_Medicine_1.ipynb b/Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_11_Mass_Transfer_in_Biology_and_Medicine_1.ipynb
index 48265c60..48265c60 100755
--- a/_Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_11_Mass_Transfer_in_Biology_and_Medicine_1.ipynb
+++ b/Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_11_Mass_Transfer_in_Biology_and_Medicine_1.ipynb
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index 24a8b3c9..24a8b3c9 100755
--- a/_Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_12_Diffrential_Distillation.ipynb
+++ b/Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_12_Diffrential_Distillation.ipynb
diff --git a/_Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_12_Diffrential_Distillation_1.ipynb b/Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_12_Diffrential_Distillation_1.ipynb
index 8751d41e..8751d41e 100755
--- a/_Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_12_Diffrential_Distillation_1.ipynb
+++ b/Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_12_Diffrential_Distillation_1.ipynb
diff --git a/_Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_13_Staged_Distillation.ipynb b/Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_13_Staged_Distillation.ipynb
index 3d3edb09..3d3edb09 100755
--- a/_Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_13_Staged_Distillation.ipynb
+++ b/Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_13_Staged_Distillation.ipynb
diff --git a/_Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_13_Staged_Distillation_1.ipynb b/Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_13_Staged_Distillation_1.ipynb
index 7b129636..7b129636 100755
--- a/_Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_13_Staged_Distillation_1.ipynb
+++ b/Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_13_Staged_Distillation_1.ipynb
diff --git a/_Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_14_Extraction.ipynb b/Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_14_Extraction.ipynb
index 91485f40..91485f40 100755
--- a/_Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_14_Extraction.ipynb
+++ b/Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_14_Extraction.ipynb
diff --git a/_Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_14_Extraction_1.ipynb b/Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_14_Extraction_1.ipynb
index 622c6af4..622c6af4 100755
--- a/_Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_14_Extraction_1.ipynb
+++ b/Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_14_Extraction_1.ipynb
diff --git a/_Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_15_Adsorption.ipynb b/Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_15_Adsorption.ipynb
index 034f965c..034f965c 100755
--- a/_Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_15_Adsorption.ipynb
+++ b/Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_15_Adsorption.ipynb
diff --git a/_Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_15_Adsorption_1.ipynb b/Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_15_Adsorption_1.ipynb
index 2a11bdb6..2a11bdb6 100755
--- a/_Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_15_Adsorption_1.ipynb
+++ b/Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_15_Adsorption_1.ipynb
diff --git a/_Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_16_General_Questions_and_Heterogeneous_Chemical_Reactions.ipynb b/Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_16_General_Questions_and_Heterogeneous_Chemical_Reactions.ipynb
index d0d24a1e..d0d24a1e 100755
--- a/_Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_16_General_Questions_and_Heterogeneous_Chemical_Reactions.ipynb
+++ b/Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_16_General_Questions_and_Heterogeneous_Chemical_Reactions.ipynb
diff --git a/_Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_16_General_Questions_and_Heterogeneous_Chemical_Reactions_1.ipynb b/Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_16_General_Questions_and_Heterogeneous_Chemical_Reactions_1.ipynb
index 6497d66e..6497d66e 100755
--- a/_Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_16_General_Questions_and_Heterogeneous_Chemical_Reactions_1.ipynb
+++ b/Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_16_General_Questions_and_Heterogeneous_Chemical_Reactions_1.ipynb
diff --git a/_Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_18_Membranes.ipynb b/Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_18_Membranes.ipynb
index af6983a6..af6983a6 100755
--- a/_Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_18_Membranes.ipynb
+++ b/Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_18_Membranes.ipynb
diff --git a/_Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_18_Membranes_1.ipynb b/Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_18_Membranes_1.ipynb
index 18e5e1ad..18e5e1ad 100755
--- a/_Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_18_Membranes_1.ipynb
+++ b/Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_18_Membranes_1.ipynb
diff --git a/_Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_19_Controlled_Release_and_Related_Phenomena.ipynb b/Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_19_Controlled_Release_and_Related_Phenomena.ipynb
index d24075ad..d24075ad 100755
--- a/_Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_19_Controlled_Release_and_Related_Phenomena.ipynb
+++ b/Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_19_Controlled_Release_and_Related_Phenomena.ipynb
diff --git a/_Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_19_Controlled_Release_and_Related_Phenomena_1.ipynb b/Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_19_Controlled_Release_and_Related_Phenomena_1.ipynb
index c8f3ce13..c8f3ce13 100755
--- a/_Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_19_Controlled_Release_and_Related_Phenomena_1.ipynb
+++ b/Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_19_Controlled_Release_and_Related_Phenomena_1.ipynb
diff --git a/_Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_20_Heat_Transfer.ipynb b/Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_20_Heat_Transfer.ipynb
index eb5ec1f3..eb5ec1f3 100755
--- a/_Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_20_Heat_Transfer.ipynb
+++ b/Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_20_Heat_Transfer.ipynb
diff --git a/_Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_20_Heat_Transfer_1.ipynb b/Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_20_Heat_Transfer_1.ipynb
index 28b1a62b..28b1a62b 100755
--- a/_Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_20_Heat_Transfer_1.ipynb
+++ b/Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_20_Heat_Transfer_1.ipynb
diff --git a/_Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_21_Simultaneous_Heat_and_Mass_Transfer.ipynb b/Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_21_Simultaneous_Heat_and_Mass_Transfer.ipynb
index aa196c71..aa196c71 100755
--- a/_Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_21_Simultaneous_Heat_and_Mass_Transfer.ipynb
+++ b/Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_21_Simultaneous_Heat_and_Mass_Transfer.ipynb
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index a89f7789..a89f7789 100755
--- a/_Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_21_Simultaneous_Heat_and_Mass_Transfer_1.ipynb
+++ b/Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_21_Simultaneous_Heat_and_Mass_Transfer_1.ipynb
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index d2335059..d2335059 100755
--- a/_Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_3_Diffusion_in_Concentrated_Solution.ipynb
+++ b/Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_3_Diffusion_in_Concentrated_Solution.ipynb
diff --git a/_Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_3_Diffusion_in_Concentrated_Solution_1.ipynb b/Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_3_Diffusion_in_Concentrated_Solution_1.ipynb
index df521927..df521927 100755
--- a/_Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_3_Diffusion_in_Concentrated_Solution_1.ipynb
+++ b/Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_3_Diffusion_in_Concentrated_Solution_1.ipynb
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index 45bd9c35..45bd9c35 100755
--- a/_Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_4_Dispersion.ipynb
+++ b/Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_4_Dispersion.ipynb
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index 217c0bae..217c0bae 100755
--- a/_Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_4_Dispersion_1.ipynb
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index 6e5023a9..6e5023a9 100755
--- a/_Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_5_Values_of_Diffusion_Coefficient.ipynb
+++ b/Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_5_Values_of_Diffusion_Coefficient.ipynb
diff --git a/_Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_5_Values_of_Diffusion_Coefficient_1.ipynb b/Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_5_Values_of_Diffusion_Coefficient_1.ipynb
index 9f6a049e..9f6a049e 100755
--- a/_Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_5_Values_of_Diffusion_Coefficient_1.ipynb
+++ b/Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_5_Values_of_Diffusion_Coefficient_1.ipynb
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index 44bfdd35..44bfdd35 100755
--- a/_Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_6_Diffusion_of_Interacting_Species.ipynb
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index 9eb11af4..9eb11af4 100755
--- a/_Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_6_Diffusion_of_Interacting_Species_1.ipynb
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index 4116c57a..4116c57a 100755
--- a/_Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_8_Fundamentals_of_Mass_Transfer_.ipynb
+++ b/Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_8_Fundamentals_of_Mass_Transfer_.ipynb
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index 3c2df3d6..3c2df3d6 100755
--- a/_Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_8_Fundamentals_of_Mass_Transfer__1.ipynb
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index f6f97301..f6f97301 100755
--- a/_Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_9__Theories_of_Mass_Transfer.ipynb
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index b0017fa1..b0017fa1 100755
--- a/_Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_9__Theories_of_Mass_Transfer_1.ipynb
+++ b/Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/Chapter_9__Theories_of_Mass_Transfer_1.ipynb
diff --git a/_Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/README.txt b/Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/README.txt
index 76e8e01b..76e8e01b 100755
--- a/_Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/README.txt
+++ b/Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/README.txt
diff --git a/_Diffusion:_Mass_Transfer_In_Fluid_Systems/screenshots/CH19.png b/Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/screenshots/CH19.png
index 742b4078..742b4078 100755
--- a/_Diffusion:_Mass_Transfer_In_Fluid_Systems/screenshots/CH19.png
+++ b/Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/screenshots/CH19.png
diff --git a/_Diffusion:_Mass_Transfer_In_Fluid_Systems/screenshots/CH3.png b/Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/screenshots/CH3.png
index 168ddb9f..168ddb9f 100755
--- a/_Diffusion:_Mass_Transfer_In_Fluid_Systems/screenshots/CH3.png
+++ b/Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/screenshots/CH3.png
diff --git a/_Diffusion:_Mass_Transfer_In_Fluid_Systems/screenshots/CH5.png b/Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/screenshots/CH5.png
index cb655050..cb655050 100755
--- a/_Diffusion:_Mass_Transfer_In_Fluid_Systems/screenshots/CH5.png
+++ b/Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/screenshots/CH5.png
diff --git a/_Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/README.txt b/Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/README.txt
index d6e4f43d..d6e4f43d 100755
--- a/_Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/README.txt
+++ b/Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/README.txt
diff --git a/_Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch1.ipynb b/Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch1.ipynb
index 68dcda86..68dcda86 100755
--- a/_Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch1.ipynb
+++ b/Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch1.ipynb
diff --git a/_Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch10.ipynb b/Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch10.ipynb
index abc4f8cf..abc4f8cf 100755
--- a/_Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch10.ipynb
+++ b/Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch10.ipynb
diff --git a/_Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch10_1.ipynb b/Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch10_1.ipynb
index abc4f8cf..abc4f8cf 100755
--- a/_Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch10_1.ipynb
+++ b/Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch10_1.ipynb
diff --git a/_Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch11.ipynb b/Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch11.ipynb
index 1fc63a70..1fc63a70 100755
--- a/_Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch11.ipynb
+++ b/Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch11.ipynb
diff --git a/_Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch11_1.ipynb b/Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch11_1.ipynb
index 1fc63a70..1fc63a70 100755
--- a/_Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch11_1.ipynb
+++ b/Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch11_1.ipynb
diff --git a/_Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch12.ipynb b/Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch12.ipynb
index fbe22bb8..fbe22bb8 100755
--- a/_Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch12.ipynb
+++ b/Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch12.ipynb
diff --git a/_Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch12_1.ipynb b/Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch12_1.ipynb
index fbe22bb8..fbe22bb8 100755
--- a/_Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch12_1.ipynb
+++ b/Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch12_1.ipynb
diff --git a/_Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch1_1.ipynb b/Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch1_1.ipynb
index 68dcda86..68dcda86 100755
--- a/_Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch1_1.ipynb
+++ b/Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch1_1.ipynb
diff --git a/_Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch2.ipynb b/Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch2.ipynb
index cbafa256..cbafa256 100755
--- a/_Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch2.ipynb
+++ b/Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch2.ipynb
diff --git a/_Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch2_1.ipynb b/Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch2_1.ipynb
index a2bb8ad8..a2bb8ad8 100755
--- a/_Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch2_1.ipynb
+++ b/Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch2_1.ipynb
diff --git a/_Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch3.ipynb b/Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch3.ipynb
index e9592db7..e9592db7 100755
--- a/_Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch3.ipynb
+++ b/Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch3.ipynb
diff --git a/_Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch3_1.ipynb b/Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch3_1.ipynb
index e9592db7..e9592db7 100755
--- a/_Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch3_1.ipynb
+++ b/Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch3_1.ipynb
diff --git a/_Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch4.ipynb b/Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch4.ipynb
index ed878662..ed878662 100755
--- a/_Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch4.ipynb
+++ b/Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch4.ipynb
diff --git a/_Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch4_1.ipynb b/Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch4_1.ipynb
index ed878662..ed878662 100755
--- a/_Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch4_1.ipynb
+++ b/Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch4_1.ipynb
diff --git a/_Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch5.ipynb b/Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch5.ipynb
index c510fa44..c510fa44 100755
--- a/_Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch5.ipynb
+++ b/Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch5.ipynb
diff --git a/_Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch5_1.ipynb b/Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch5_1.ipynb
index c510fa44..c510fa44 100755
--- a/_Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch5_1.ipynb
+++ b/Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch5_1.ipynb
diff --git a/_Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch6.ipynb b/Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch6.ipynb
index 7de940ff..7de940ff 100755
--- a/_Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch6.ipynb
+++ b/Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch6.ipynb
diff --git a/_Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch6_1.ipynb b/Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch6_1.ipynb
index 7de940ff..7de940ff 100755
--- a/_Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch6_1.ipynb
+++ b/Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch6_1.ipynb
diff --git a/_Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch7.ipynb b/Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch7.ipynb
index 37ba8a19..37ba8a19 100755
--- a/_Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch7.ipynb
+++ b/Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch7.ipynb
diff --git a/_Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch7_1.ipynb b/Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch7_1.ipynb
index 37ba8a19..37ba8a19 100755
--- a/_Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch7_1.ipynb
+++ b/Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch7_1.ipynb
diff --git a/_Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch8.ipynb b/Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch8.ipynb
index 55e8755b..55e8755b 100755
--- a/_Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch8.ipynb
+++ b/Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch8.ipynb
diff --git a/_Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch8_1.ipynb b/Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch8_1.ipynb
index 55e8755b..55e8755b 100755
--- a/_Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch8_1.ipynb
+++ b/Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch8_1.ipynb
diff --git a/_Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch9.ipynb b/Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch9.ipynb
index a2e2372f..a2e2372f 100755
--- a/_Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch9.ipynb
+++ b/Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch9.ipynb
diff --git a/_Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch9_1.ipynb b/Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch9_1.ipynb
index a2e2372f..a2e2372f 100755
--- a/_Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch9_1.ipynb
+++ b/Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/ch9_1.ipynb
diff --git a/_Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/screenshots/energy_stored3.png b/Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/screenshots/energy_stored3.png
index 4df63985..4df63985 100755
--- a/_Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/screenshots/energy_stored3.png
+++ b/Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/screenshots/energy_stored3.png
diff --git a/_Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/screenshots/energy_stored3_1.png b/Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/screenshots/energy_stored3_1.png
index 4df63985..4df63985 100755
--- a/_Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/screenshots/energy_stored3_1.png
+++ b/Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/screenshots/energy_stored3_1.png
diff --git a/_Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/screenshots/magnetic_flux12.png b/Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/screenshots/magnetic_flux12.png
index 1179606e..1179606e 100755
--- a/_Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/screenshots/magnetic_flux12.png
+++ b/Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/screenshots/magnetic_flux12.png
diff --git a/_Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/screenshots/magnetic_flux12_1.png b/Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/screenshots/magnetic_flux12_1.png
index 1179606e..1179606e 100755
--- a/_Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/screenshots/magnetic_flux12_1.png
+++ b/Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/screenshots/magnetic_flux12_1.png
diff --git a/_Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/screenshots/pitch_factor7.png b/Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/screenshots/pitch_factor7.png
index c7b428f6..c7b428f6 100755
--- a/_Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/screenshots/pitch_factor7.png
+++ b/Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/screenshots/pitch_factor7.png
diff --git a/_Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/screenshots/pitch_factor7_1.png b/Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/screenshots/pitch_factor7_1.png
index c7b428f6..c7b428f6 100755
--- a/_Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/screenshots/pitch_factor7_1.png
+++ b/Electric_Machinery_And_Transformers_by_B._S._Guru_And_H._R._Hiziroglu/screenshots/pitch_factor7_1.png
diff --git a/Electrical_And_Electronics_Engineering_Materials_by_J._B._Gupta/chap1.ipynb b/Electrical_And_Electronics_Engineering_Materials_by_J._B._Gupta/chap1.ipynb
new file mode 100644
index 00000000..211165e2
--- /dev/null
+++ b/Electrical_And_Electronics_Engineering_Materials_by_J._B._Gupta/chap1.ipynb
@@ -0,0 +1,220 @@
+{
+ "metadata": {
+  "name": "",
+  "signature": "sha256:8e8826d7c281bfe44efc7f7351ec8ba5a5829ab40f667469ca3e50c8e761a1f8"
+ },
+ "nbformat": 3,
+ "nbformat_minor": 0,
+ "worksheets": [
+  {
+   "cells": [
+    {
+     "cell_type": "heading",
+     "level": 1,
+     "metadata": {},
+     "source": [
+      "Chapter 1 - Crystal Structures of Materials"
+     ]
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa3 page 25"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "from __future__ import division\n",
+      "from math import sqrt\n",
+      "#given data\n",
+      "#atomic radius\n",
+      "r=1.278  #in Angstrum\n",
+      "#atomic weight\n",
+      "aw=63.5 \n",
+      "#Avogadro's number\n",
+      "an=6.023*10**23 \n",
+      "#copper has FCC structure for which\n",
+      "a=(4*r)/sqrt(2) # in Angstrum\n",
+      "a=a*10**-10 #in m\n",
+      "#Mass of one atom \n",
+      "m=aw/an #in gm\n",
+      "m=m*10**-3 #in kg\n",
+      "#volume of one unit cell of copper crystal,\n",
+      "V=a**3 #in meter cube\n",
+      "#Number of atoms present in one unit cell of Cu(FCC Structure),\n",
+      "n=4 \n",
+      "#Density of crystal\n",
+      "rho=(m*n)/V #in kg/m**3\n",
+      "print \"Density of crystal is : \",round(rho,0),\"kg/m**3\" "
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Density of crystal is :  8929.0 kg/m**3\n"
+       ]
+      }
+     ],
+     "prompt_number": 1
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa4 page 27"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "from math import pi, sin\n",
+      "#given data :\n",
+      "#wavelength\n",
+      "lamda=1.539  #in Angstrum\n",
+      "#angle\n",
+      "theta=22.5  # in degree\n",
+      "n=1 #(first order)\n",
+      "\n",
+      "# Formula n*lamda=2*d*sin(theta) , so\n",
+      "# interplaner distance,\n",
+      "d=lamda/(2*sin(theta*pi/180)) \n",
+      "print \"Interplaner distance is : \",round(d,2),\"  Angstrum\""
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Interplaner distance is :  2.01   Angstrum\n"
+       ]
+      }
+     ],
+     "prompt_number": 2
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa5 page 27"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "#given data :\n",
+      "n=2 \n",
+      "d=0.4 # in nenometer\n",
+      "d=d*10**-9 # in meter\n",
+      "theta=16.8/2 # in degree\n",
+      "#using Bragg's equation we have n*lamda=2*d*sin(theta), so\n",
+      "lamda=(2*d*sin(8.4*pi/180))/n \n",
+      "print \"Wavelength of X-rays used is : \",round(lamda*10**10,3),\" Angstrum\" "
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Wavelength of X-rays used is :  0.584  Angstrum\n"
+       ]
+      }
+     ],
+     "prompt_number": 3
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa6 page 28"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "#given data :\n",
+      "a=3.15  #in Angstrum\n",
+      "a=a*10**-10 #in meter\n",
+      "#angle\n",
+      "theta=20.2 #in degree\n",
+      "n=1 #(first order)\n",
+      "#for BCC crystal\n",
+      "d110=a/sqrt(2) #in meter\n",
+      "#Formula n*lamda=2*d*sin(theta)\n",
+      "lamda=(2*d110*sin(theta*pi/180))/n #in meter\n",
+      "print \"Wavelength is : \",round(lamda*10**10,2),\" Angstrum\""
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Wavelength is :  1.54  Angstrum\n"
+       ]
+      }
+     ],
+     "prompt_number": 4
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa7 page 28"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "from math import asin, degrees\n",
+      "#given data :\n",
+      "lamda=0.842  #in Angstrum\n",
+      "lamda=lamda*10**-10  # in meter\n",
+      "#theta=8degree 35minutes\n",
+      "theta=8+35/60 #in degree\n",
+      "n=1 #(first order)\n",
+      "#Formula n*lamda=2*d*sin(theta)\n",
+      "d=n*lamda/(2*sin(pi/180*theta))\n",
+      "#For third Order reflection :\n",
+      "#Formula n*lamda=2*d*sin(theta)\n",
+      "n=3 #order\n",
+      "theta=degrees(asin(n*lamda/(2*d)) )\n",
+      "print \"Angle of incidence for third order reflection\",round(theta),\"degree \" # Answer wrong in the textbook."
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Angle of incidence for third order reflection 27.0 degree \n"
+       ]
+      }
+     ],
+     "prompt_number": 5
+    }
+   ],
+   "metadata": {}
+  }
+ ]
+}
\ No newline at end of file
diff --git a/Electrical_And_Electronics_Engineering_Materials_by_J._B._Gupta/chap2.ipynb b/Electrical_And_Electronics_Engineering_Materials_by_J._B._Gupta/chap2.ipynb
new file mode 100644
index 00000000..568d4bd1
--- /dev/null
+++ b/Electrical_And_Electronics_Engineering_Materials_by_J._B._Gupta/chap2.ipynb
@@ -0,0 +1,1553 @@
+{
+ "metadata": {
+  "name": "",
+  "signature": "sha256:df0529c98b437c18203d09c26cf952aa676f19a5d6a69450a8afb37e90e41d49"
+ },
+ "nbformat": 3,
+ "nbformat_minor": 0,
+ "worksheets": [
+  {
+   "cells": [
+    {
+     "cell_type": "heading",
+     "level": 1,
+     "metadata": {},
+     "source": [
+      "Chapter 2 - Conductivity of Metals"
+     ]
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa2.1 page 50"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "#given data :\n",
+      "J=2.4  #in A/mm**2\n",
+      "J=2.4*10**6  #in A/m**2\n",
+      "n=5*10**28  #unitless\n",
+      "e=1.6*10**-19  # in coulomb\n",
+      "#Formula : J=e*n*v\n",
+      "v=J/(e*n) #in m/s\n",
+      "print \"Drift velocity is : \",(v),\" m/s or \",(v*10**3),\" mm/s\""
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Drift velocity is :  0.0003  m/s or  0.3  mm/s\n"
+       ]
+      }
+     ],
+     "prompt_number": 41
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa2 page 50"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "#given data :\n",
+      "#Electron density\n",
+      "n=1*10**24 #unit less\n",
+      "#Electron charge\n",
+      "e=1.6*10**-19  # in coulomb\n",
+      "#Drift velocity\n",
+      "v=1.5*10**-2  # in meter per second\n",
+      "#cross-sectional area\n",
+      "A=1  # in centimeter square\n",
+      "A=1*10**-4  # in meter square\n",
+      "I=e*n*v*A # in ampere\n",
+      "print \"Magnitude of current is :\",(I),\" A\""
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Magnitude of current is : 0.24  A\n"
+       ]
+      }
+     ],
+     "prompt_number": 42
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa2.3 page 50"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "#given data :\n",
+      "miu_e=7.04*10**-3  #in m**2/V-s\n",
+      "n=5.8*10**28   # in /m**3\n",
+      "e=1.6*10**-19  # in coulomb\n",
+      "m=9.1*10**-31 #in kg\n",
+      "#(i) Relaxation time,\n",
+      "tau=miu_e/e*m \n",
+      "print \"Relaxation time is : \",(tau),\" second\" \n",
+      "sigma=(n*e*miu_e) \n",
+      "#(ii) Resistivity of conductor,\n",
+      "rho=1/sigma \n",
+      "print \"Resistivity of conductor is : %0.3e\"%rho,\" ohm-meter\" "
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Relaxation time is :  4.004e-14  second\n",
+        "Resistivity of conductor is : 1.531e-08  ohm-meter\n"
+       ]
+      }
+     ],
+     "prompt_number": 43
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa4 page 50"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "#given data :\n",
+      "rho=1.73*10**-8 #in ohm-meter\n",
+      "toh=2.42*10**-14   #in second\n",
+      "e=1.6*10**-19  #in C\n",
+      "m=9.1*10**-31 #in kg\n",
+      "sigma=1/rho \n",
+      "#(i) Number of free electrons per m**3\n",
+      "print \"Number of free electrons per cube meter is : \",(n)\n",
+      "n=(m*sigma)/(e**2*toh) \n",
+      "#(ii) Mobility of electrons,\n",
+      "miu_e=(e*toh)/m \n",
+      "print \"Mobility of electrons is : %0.3e\"%(miu_e),\" m**2/V-s\" \n",
+      "#Note: Answer in the book is wrong"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Number of free electrons per cube meter is :  5.8e+28\n",
+        "Mobility of electrons is : 4.255e-03  m**2/V-s\n"
+       ]
+      }
+     ],
+     "prompt_number": 44
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa5 page 51"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "#given data :\n",
+      "rho=1.54*10**-8  #in ohm-meter\n",
+      "#since sigma=1/roh\n",
+      "sigma=1/rho \n",
+      "n=5.8*10**28   #unit less\n",
+      "e=1.6*10**-19  #in C (electron charge)\n",
+      "m=9.1*10**-31 #in kg (mass of electron)\n",
+      "#(i) Relaxation time\n",
+      "toh=(sigma*m)/(n*e**2) \n",
+      "print \"(i) Relaxation time of electrons is : %0.3e\"%(toh),\" seconds\" \n",
+      "#(ii) Mobility of electrons,\n",
+      "miu_e=(e*toh)/m \n",
+      "print \"(ii) Mobility of electrons is : %0.3e\"%(miu_e),\" m**2/V-s\" "
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "(i) Relaxation time of electrons is : 3.980e-14  seconds\n",
+        "(ii) Mobility of electrons is : 6.997e-03  m**2/V-s\n"
+       ]
+      }
+     ],
+     "prompt_number": 45
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa2.6 page 51"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "#given data :\n",
+      "rho=1.7*10**-8  #in ohm-meter\n",
+      "#since sigma=1/roh\n",
+      "sigma=1/rho \n",
+      "n=8.5*10**28   #unit less\n",
+      "e=1.6*10**-19  #in C (electron charge)\n",
+      "m=9.1*10**-31 #in kg\n",
+      "# Relaxation time\n",
+      "toh=(sigma*m)/(n*e**2) \n",
+      "print \" Relaxation time of electrons is : %0.3e\"%(toh),\" seconds\" "
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        " Relaxation time of electrons is : 2.460e-14  seconds\n"
+       ]
+      }
+     ],
+     "prompt_number": 46
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa2.7 page 51"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "#given data :\n",
+      "E=100 #in V/m\n",
+      "rho=1.5*10**-8  #in ohm-meter\n",
+      "#since sigma=1/roh\n",
+      "sigma=1/rho \n",
+      "n=6*10**28   #unit less\n",
+      "e=1.601*10**-19  #in C\n",
+      "m=9.107*10**-31 #in kg\n",
+      "# Relaxation time\n",
+      "toh=(sigma*m)/(n*e**2) \n",
+      "print \"(i) Relaxation time of electrons is : %0.3e\"%(toh),\" seconds\" \n",
+      "#Drift velocity\n",
+      "v=(e*E*toh)/m \n",
+      "print \"(ii) Drift velocity is : %0.3f\"%(v),\" m/s\" "
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "(i) Relaxation time of electrons is : 3.948e-14  seconds\n",
+        "(ii) Drift velocity is : 0.694  m/s\n"
+       ]
+      }
+     ],
+     "prompt_number": 47
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa2.8 page 52"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "from math import pi\n",
+      "#given data :\n",
+      "#Diameter of copper wire\n",
+      "d=2 #in milimeter\n",
+      "d=.002 #in meter\n",
+      "#conductivity of copper\n",
+      "nita=5.8*10**7 #in second per meter\n",
+      "#Electron mobility\n",
+      "miu_e=.0032 #in meter square per volt-second\n",
+      "#Applied electric field\n",
+      "E=20 #in mV/m\n",
+      "E=.02  #in V/m\n",
+      "e=1.6*10**-19 \n",
+      "#(i) From eq. (2.13)\n",
+      "#charge density\n",
+      "n=nita/(e*miu_e) #in per meter cube\n",
+      "print \"(i) Charge density is : %0.3e\"%(n),\" /meter cube\" \n",
+      "#(ii) from eq. (2.9)\n",
+      "#current density\n",
+      "J=nita*E # in A/m**2\n",
+      "print \"(ii) Current density is : \",(J),\" A/m**2\" \n",
+      "#(iii) Current flowing in the wire I=J* Area of x-section of wire\n",
+      "# Area of x-section of wire= (pi*d**2)/4\n",
+      "I=(J*pi*d**2)/4 \n",
+      "print \"(iii) Current flowing in the wire is : %0.2e\"%(I),\" A\" \n",
+      "#(iv) form eq.2.14\n",
+      "#Electron drift velocity\n",
+      "v=miu_e*E \n",
+      "print \"(iv) Electron drift velocity is : %0.1e\"%(v),\" m/s\" "
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "(i) Charge density is : 1.133e+29  /meter cube\n",
+        "(ii) Current density is :  1160000.0  A/m**2\n",
+        "(iii) Current flowing in the wire is : 3.64e+00  A\n",
+        "(iv) Electron drift velocity is : 6.4e-05  m/s\n"
+       ]
+      }
+     ],
+     "prompt_number": 48
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa2.9 page 52"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "#given data\n",
+      "rho=0.5  # in ohm-meter\n",
+      "J=100  #in A/m**2\n",
+      "miu_e=0.4  #in m**2/V-s\n",
+      "E=J*rho  # since E=J/sigma\n",
+      "# Formula v=miu_e*E\n",
+      "v=miu_e*E \n",
+      "print \"Electron drift velocity is : \",(v),\" m/s\" \n",
+      "print \"Time taken by the electron to travel 10*10**-6 m in crystal =\",\n",
+      "# let Time taken by the electron to travel 10*10**-6 m in crystal = t\n",
+      "t=(10*10**-6)/v \n",
+      "print (t),\"second\" "
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Electron drift velocity is :  20.0  m/s\n",
+        "Time taken by the electron to travel 10*10**-6 m in crystal = 5e-07 second\n"
+       ]
+      }
+     ],
+     "prompt_number": 49
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa10 page 52"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "#given data\n",
+      "miu_e=0.17 #in m**2/V-s\n",
+      "miu_h=0.035 #in m**2/V-s\n",
+      "nita_i=1.1*10**16  #in /m**3\n",
+      "e=1.6*10**-19 # in C (electron charge)\n",
+      "# Intrinsic conductivity,\n",
+      "sigma_i=(nita_i*e)*(miu_e+miu_h) \n",
+      "IntrinsicResistivity=1/sigma_i \n",
+      "print \"Intrinsic resistivity is : %0.2e\"%(IntrinsicResistivity),\" ohm-meter\" "
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Intrinsic resistivity is : 2.77e+03  ohm-meter\n"
+       ]
+      }
+     ],
+     "prompt_number": 50
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa11 page 52"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "#given data\n",
+      "rho_i=2*10**-3  #in ohm-m  (there is miss printed in this line in the book)\n",
+      "sigma_i=1/rho_i \n",
+      "miu_e=0.3 # in m**2/V-s\n",
+      "miu_h=0.1 #  in m**2/V-s\n",
+      "e=1.6*10**-19  # in C\n",
+      "# Formula sigma_i=nita_i*e*(miu_e+miu_h)\n",
+      "nita_i=sigma_i/(e*(miu_e+miu_h)) \n",
+      "print \"Carrier density is : %0.2e\"%(nita_i),\" /m**3\" "
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Carrier density is : 7.81e+21  /m**3\n"
+       ]
+      }
+     ],
+     "prompt_number": 51
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa2.13 page 56"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "from __future__ import division\n",
+      "#given data\n",
+      "R_15=250 # in ohm\n",
+      "R_t2=300  # in ohm\n",
+      "alpha=0.0039 # in degree C\n",
+      "t1=15 \n",
+      "#Formula R_t2 = R_15 * [1 + alpha1*(t2 - t1)]\n",
+      "t2=((R_t2/R_15)-1)/alpha+t1 \n",
+      "print \"Temperature when its resistance is 300 ohms is : \",round(t2,1),\" degree C\" "
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Temperature when its resistance is 300 ohms is :  66.3  degree C\n"
+       ]
+      }
+     ],
+     "prompt_number": 52
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa2.15 page 57"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "#given data\n",
+      "alpha0=0.0038 # in ohm/ohm/degree C\n",
+      "t1=20  #in degree C\n",
+      "alpha20=1/(1/alpha0+t1) \n",
+      "R1=400 #in ohm\n",
+      "#Formula R2=R1*[1+alpha20*(t2-t1)]\n",
+      "R2=R1*(1+alpha20*(80-20)) \n",
+      "print \"Resistance of wire at 80 degree C si : \",round(R2,1),\" ohm\""
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Resistance of wire at 80 degree C si :  484.8  ohm\n"
+       ]
+      }
+     ],
+     "prompt_number": 53
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa2.16 page 57"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "# given data\n",
+      "R1 = 50 # ohm\n",
+      "R2 = 57.2 # ohm\n",
+      "t1 = 25 # degree C\n",
+      "t2 = 70 # degree C\n",
+      "\n",
+      "\n",
+      "from sympy import symbols, solve, N\n",
+      "alfa0, R0 = symbols('alfa0 R0') # temperature coefficient at 0 degree C\n",
+      "\n",
+      "# Accrding to formula :\n",
+      "#r1 = R0(1+t1*alfa0)\n",
+      "#r2 = R0(1+t2*alfa0)\n",
+      "r1byr2 = R1/R2\n",
+      "alfa0 = solve((1+t1*alfa0)/(1+t2*alfa0)-r1byr2)[0]\n",
+      "alfa0 = N(alfa0, 3)\n",
+      "\n",
+      "print \"alpha0 = \",alfa0,\" ohm/ohm/degree C\" "
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "alpha0 =  0.00348  ohm/ohm/degree C\n"
+       ]
+      }
+     ],
+     "prompt_number": 54
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa2.17 page 57"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "# given data\n",
+      "R1 = 45 # ohm\n",
+      "R2 = 59 # ohm\n",
+      "t1 = 25 # degree C\n",
+      "t2 = 75 # degree C\n",
+      "\n",
+      "\n",
+      "from sympy import symbols, solve, N\n",
+      "alfa0, R0 = symbols('alfa0 R0') # temperature coefficient at 0 degree C\n",
+      "\n",
+      "# Accrding to formula :\n",
+      "#r1 = R0(1+t1*alfa0)\n",
+      "#r2 = R0(1+t2*alfa0)\n",
+      "r1byr2 = R1/R2\n",
+      "alfa0 = solve((1+t1*alfa0)/(1+t2*alfa0)-r1byr2)[0]\n",
+      "alfa0 = N(alfa0, 5)\n",
+      "\n",
+      "print \"alpha0 = %0.2e\"%alfa0,\" ohm/ohm/degree C\" "
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "alpha0 = 7.37e-03  ohm/ohm/degree C\n"
+       ]
+      }
+     ],
+     "prompt_number": 55
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa2.18 page 58"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "# given data\n",
+      "R1 = 3.146 # ohm\n",
+      "R2 = 3.767 # ohm\n",
+      "t1 = 40 # degree C\n",
+      "t2 = 100 # degree C\n",
+      "\n",
+      "\n",
+      "from sympy import symbols, solve, N\n",
+      "alfa0, R0 = symbols('alfa0 R0') # temperature coefficient at 0 degree C\n",
+      "\n",
+      "# Accrding to formula :\n",
+      "#r1 = R0(1+t1*alfa0)\n",
+      "#r2 = R0(1+t2*alfa0)\n",
+      "r1byr2 = R1/R2\n",
+      "alfa0 = solve((1+t1*alfa0)/(1+t2*alfa0)-r1byr2)[0]\n",
+      "alfa0 = N(alfa0, 3)\n",
+      "\n",
+      "print \"Temperature coefficient of resistance at 40 degree C = \",\n",
+      "alpha40=1/(1/alpha0+40) \n",
+      "print round(alpha40,5)\n",
+      "#Formula R1 = R0 * (1+40*alpha0)\n",
+      "R0=R1/(1+40*alpha0) \n",
+      "print \"Resistance of platinum coil at 0 degree C is : \",round(R0,3),\" ohm \" "
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Temperature coefficient of resistance at 40 degree C =  0.0033\n",
+        "Resistance of platinum coil at 0 degree C is :  2.731  ohm \n"
+       ]
+      }
+     ],
+     "prompt_number": 56
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa2.19 page 58"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "# given data\n",
+      "R1 = 18 # ohm\n",
+      "R2 = 20 # ohm\n",
+      "R3 = 21 # ohm\n",
+      "t1 = 20 # degree C\n",
+      "t2 = 50 # degree C\n",
+      "ts = 15 # degree C # surrounding temperature\n",
+      "\n",
+      "from sympy import symbols, solve, N\n",
+      "alfa0, R0, t = symbols('alfa0 R0 t') # temperature coefficient at 0 degree C\n",
+      "\n",
+      "# Accrding to formula :\n",
+      "#r1 = R0(1+t1*alfa0)\n",
+      "#r2 = R0(1+t2*alfa0)\n",
+      "#r3 = R0(1+t*alfa0)\n",
+      "r1byr2 = R1/R2\n",
+      "alfa0 = solve((1+t1*alfa0)/(1+t2*alfa0)-r1byr2)[0]\n",
+      "alfa0 = N(alfa0, 3)\n",
+      "\n",
+      "r3byr2 = R3/R2\n",
+      "t = solve(r3byr2 - (1+alfa0*t)/(1+alfa0*t2), t)[0]\n",
+      "tr = t-ts # temp. rise\n",
+      "print \"Temperature rise = %0.f degree C\" %tr"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Temperature rise = 50 degree C\n"
+       ]
+      }
+     ],
+     "prompt_number": 57
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa2.20 page 59"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "from __future__ import division\n",
+      "from fractions import Fraction\n",
+      "#given data\n",
+      "alpha20=1/254.5 # in ohm/ohm/degree C\n",
+      "t2=60 #degree C\n",
+      "t1=20 #degree C\n",
+      "rho0=1.6*10**-6 \n",
+      "alpha60=1/(1/alpha20+(t2-t1)) \n",
+      "print \"Temperature coefficient of resistance at 60 degree C is : \",Fraction(alpha60).limit_denominator(1000),\"or\",round(alpha60,5),\" ohm/(ohm/degree C)\" \n",
+      "#from alpha20=1/(1/alpha0+20)\n",
+      "alpha0=1/(1/alpha20-20) \n",
+      "#Formula rho60=rho0*(1+alpha0*t)\n",
+      "rho60=rho0*(1+alpha0*t2) \n",
+      "print \"Specific resistance at 60 degree C is : %0.4e\"%(rho60),\" ohm-cm\""
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Temperature coefficient of resistance at 60 degree C is :  2/589 or 0.0034  ohm/(ohm/degree C)\n",
+        "Specific resistance at 60 degree C is : 2.0094e-06  ohm-cm\n"
+       ]
+      }
+     ],
+     "prompt_number": 58
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa2.21 page 59"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "#given data\n",
+      "R=95.5 #in ohm\n",
+      "l=1 #in meter\n",
+      "d=0.08 #in mm\n",
+      "d=d*10**-3 #in meter\n",
+      "a=(pi*d**2)/4 \n",
+      "#Formula R=rho*l/a\n",
+      "rho=R*a/l \n",
+      "print \"Resistance of the wire material is : %0.3e\"%(rho),\" ohm-meter\""
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Resistance of the wire material is : 4.800e-07  ohm-meter\n"
+       ]
+      }
+     ],
+     "prompt_number": 59
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa2.22 page 59"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "#given data\n",
+      "R=4 #in ohm\n",
+      "d=0.0274 #in cm\n",
+      "d=0.000274 #in meter\n",
+      "rho=10.3 #in miu ohm-cm\n",
+      "rho=10.3*10**-8 #in ohm-m\n",
+      "a=(pi*d**2)/4 \n",
+      "\n",
+      "#Formula R=rho*l/a\n",
+      "l=R*a/rho \n",
+      "print \"Lenght of wire is : %0.2f\"%(l),\" meters\""
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Lenght of wire is : 2.29  meters\n"
+       ]
+      }
+     ],
+     "prompt_number": 60
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa2.23 page 60"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "#given data\n",
+      "V=220 # in V\n",
+      "W=100 #in watt\n",
+      "R100=V**2/W #in ohm\n",
+      "alpha20=0.005 \n",
+      "t1=20 \n",
+      "t2=2000 \n",
+      "# since R100=R20*[1+alpha20*(t2-t1)]\n",
+      "R20=R100/(1+alpha20 * (t2-t1)) \n",
+      "I20=V/R20 \n",
+      "print \"Current flowing at the instant of switching on a 100 W metal filament lamp is : \",round(I20,2),\" A\""
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Current flowing at the instant of switching on a 100 W metal filament lamp is :  4.95  A\n"
+       ]
+      }
+     ],
+     "prompt_number": 61
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa2.24 page 60"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "from fractions import Fraction\n",
+      "#given data\n",
+      "t2=50 # in degree C\n",
+      "t1=20  # in degree C\n",
+      "R1=600 # in ohm\n",
+      "R2=300 # in ohm\n",
+      "\n",
+      "# Let resistance of 600 ohm resistance at 50 degree C = R_600\n",
+      "R_600=R1*(1+(t2-t1)*.001) # in ohm\n",
+      "# Let resistance of 300 ohm resistance at 50 degree C = R_300\n",
+      "R_300=R2*(1+(t2-t1)*.004) # in ohm\n",
+      "R_50=R_600+R_300 # in ohm\n",
+      "print \"Resistance of combination at 50degree C is : \",(R_50),\" ohm\"\n",
+      "R_20=R1+R2 # in ohm\n",
+      "alpha_20=(R_50/R_20-1)/(t2-t1) \n",
+      "alpha_50=1/(1/(alpha_20)+(t2-t1)) \n",
+      "print \"Effective temperature coefficient of combination at 50 degree C is : \",Fraction(alpha_50).limit_denominator(1000),\"per degree C\""
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Resistance of combination at 50degree C is :  954.0  ohm\n",
+        "Effective temperature coefficient of combination at 50 degree C is :  1/530 per degree C\n"
+       ]
+      }
+     ],
+     "prompt_number": 62
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa2.25 page 61"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "#given data\n",
+      "toh=1.73#in micro-ohm-cm\n",
+      "tohDesh=1.74 #in micro-ohm-cm\n",
+      "sigma=1/toh # conductivities of pure metal\n",
+      "sigmaDesh=1/tohDesh #conductivities metal with impurity\n",
+      "PercentImpurity=((sigma-sigmaDesh)/sigma)*100 \n",
+      "print \" Percent impurity in the rod is : %0.4f\"%(PercentImpurity),\" %\""
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        " Percent impurity in the rod is : 0.5747  %\n"
+       ]
+      }
+     ],
+     "prompt_number": 63
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa2.26 page 64"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "#given data\n",
+      "ElectricalResistivity=2.86*10**-6 #in ohm-cm\n",
+      "sigma=1/ElectricalResistivity \n",
+      "T=273+20 # in Kelvin (Temperature)\n",
+      "#Formula K/(sigma*T)=2.44*10**-8\n",
+      "K=(2.44*10**-8*T*sigma) \n",
+      "print \"Thermal conductivity of Al = %0.2f\"%K"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Thermal conductivity of Al = 2.50\n"
+       ]
+      }
+     ],
+     "prompt_number": 64
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa2.27 page 69"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "#given data\n",
+      "E_AC=16*10**-6 #in V per degree C\n",
+      "E_BC=-34*10**-6 #in V per degree C\n",
+      "#By law of successive contact (or intermediate metals)\n",
+      "E_AB=E_AC-E_BC #in V/degree C\n",
+      "E_AB=E_AB*10**6 # in miu V/degree C\n",
+      "print \"EMF of iron with respect to constantan is : \",(E_AB),\" micro V/degree C\""
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "EMF of iron with respect to constantan is :  50.0  micro V/degree C\n"
+       ]
+      }
+     ],
+     "prompt_number": 65
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa2.28 page 69"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "#given data\n",
+      "E_AC=7.4 #in miu V per degree C\n",
+      "E_BC=-34.4 #in miu V per degree C\n",
+      "#By law of successive contact (or intermediate metals)\n",
+      "E_AB=E_AC-E_BC #in miu V/degree C\n",
+      "E_AB=E_AB*10**-6 # in  V/degree C\n",
+      "# Let Thermo-emf for a temperature difference of 250 degree C = EMF_250\n",
+      "EMF_250=E_AB*250 # in V\n",
+      "EMF_250=EMF_250*10**3 #in mV\n",
+      "print \"Termo-emf for a temperature difference of 250 degree C is \",(EMF_250),\" mV\" "
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Termo-emf for a temperature difference of 250 degree C is  10.45  mV\n"
+       ]
+      }
+     ],
+     "prompt_number": 66
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa2.29 page 70"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "#given data\n",
+      "#Take iron as metal A and copper as metal B with respect to lead\n",
+      "#For metal A:\n",
+      "p_A=16.2 \n",
+      "q_A=-0.02 \n",
+      "#For metal B:\n",
+      "p_B=2.78 \n",
+      "q_B=+0.009 \n",
+      "p_AB=p_A-p_B \n",
+      "q_AB=q_A-q_B \n",
+      "T2=210 #in degree C\n",
+      "T1=10 # in degree C\n",
+      "E=p_AB*(T2-T1)+q_AB/2*(T2**2-T1**2) \n",
+      "print \"Thermo-electric emf is : \",(E),\" micro V\" \n",
+      "Tn=-p_AB/q_AB \n",
+      "print \"Neutral temperature is : \",round(Tn,0),\" degree C\" "
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Thermo-electric emf is :  2046.0  micro V\n",
+        "Neutral temperature is :  463.0  degree C\n"
+       ]
+      }
+     ],
+     "prompt_number": 67
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa2.30 page 70"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "from math import ceil\n",
+      "#given data\n",
+      "p_A=17.34 \n",
+      "q_A=-0.0487 \n",
+      "p_B=1.36 \n",
+      "q_B=+0.0095 \n",
+      "p_AB=p_A-p_B \n",
+      "q_AB=q_A-q_B \n",
+      "T2=210 #in degree C\n",
+      "T1=10 # in degree C\n",
+      "E=p_AB*(T2-T1)+q_AB/2*(T2**2-T1**2) #in miu V\n",
+      "E=E*10**-3 #in m V\n",
+      "print \"Thermo-electric emf is : \",(ceil(E)),\" m V\" \n",
+      "Tn=-p_AB/q_AB \n",
+      "print \"Neutral temperature is : \",(ceil(Tn)),\" degree C\" \n",
+      "Tc=10 # in degree C\n",
+      "Ti=Tn+(Tn-Tc) \n",
+      "print \"Temperature of inversion is : \",(ceil(Ti)),\" degree C\" \n",
+      "E_max=15.98*(275-10)-1/2*0.0582*(275**2-10**2) #in miu V\n",
+      "E_max=E_max*10**-3 # in mV\n",
+      "print \"Maximum possible thermo-electric emf at neutral temperature that is at 275 degree C is : %0.3f\"%(E_max),\" mV\" "
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Thermo-electric emf is :  2.0  m V\n",
+        "Neutral temperature is :  275.0  degree C\n",
+        "Temperature of inversion is :  540.0  degree C\n",
+        "Maximum possible thermo-electric emf at neutral temperature that is at 275 degree C is : 2.037  mV\n"
+       ]
+      }
+     ],
+     "prompt_number": 68
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa2.31 page 72"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "#given data\n",
+      "rho=146*10**-6# in ohm-cm\n",
+      "a=1 #in cm**2\n",
+      "l=1 #in cm\n",
+      "# let current = i\n",
+      "i=0.06 #in amp \n",
+      "R=rho*l/a #in ohm\n",
+      "# Let potential difference per degree centigrade = P\n",
+      "P=i*R # By Ohm's law\n",
+      "print \"Potential difference per degree centigrade is : \",(P),\" volt\" "
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Potential difference per degree centigrade is :  8.76e-06  volt\n"
+       ]
+      }
+     ],
+     "prompt_number": 69
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa2.32 page 73"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "from sympy.mpmath import quad\n",
+      "#given data\n",
+      "T_lower=10 # in degree C\n",
+      "T_upper=150 # in degree C\n",
+      "\n",
+      "# T for iron at any temperature T degree C w.r.t. lead is given by (17.34-0.0487 T)*10**-6 and that for copper by (1.36-.0095 T)*10**-6\n",
+      "T_i = lambda T: (17.34-0.0487*T)*10**-6 #Thermo-electric power\n",
+      "T_c = lambda T: (1.36-0.0095*T)*10**-6 #Thermo-electric power\n",
+      "\n",
+      "# Thermo-electric power, P=dE/dT\n",
+      "# or dE=P*dT\n",
+      "# Thermo-emf for copper between temperature 10 degree C and 150 degree C,\n",
+      "\n",
+      "\n",
+      "E_c= quad(T_c,[T_lower,T_upper]) \n",
+      "# Thermo-emf for iron between temperature 10 degree C and 150 degree C,\n",
+      "E_i= quad(T_i,[T_lower,T_upper]) \n",
+      "# Thermo-emp for copper-iron thermo-couple\n",
+      "E=E_i-E_c \n",
+      "print \"Thermo-emf for iron between temperature 10 degree C and 150 degree C is : \",(E*10**6),\" micro V\" "
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Thermo-emf for iron between temperature 10 degree C and 150 degree C is :  1798.16  micro V\n"
+       ]
+      }
+     ],
+     "prompt_number": 70
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa2.34 page 79"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "#given data\n",
+      "Hc_0=8*10**5 #in A/m\n",
+      "Tc=7.26 #in K\n",
+      "T=4 #in K\n",
+      "Hc_T=Hc_0*(1-(T/Tc)**2)\n",
+      "print \"The critical value of magnetic field at T=4 K is : %0.4e\"%(Hc_T),\" A/m\" "
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "The critical value of magnetic field at T=4 K is : 5.5715e+05  A/m\n"
+       ]
+      }
+     ],
+     "prompt_number": 71
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa2.35 page 79"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "from __future__ import division\n",
+      "#given data\n",
+      "Hc=7900 #in A/m\n",
+      "d=1 #in mm\n",
+      "r=d/2 #in mm\n",
+      "r=r*10**-3 #in m\n",
+      "Ic=2*pi*r*Hc \n",
+      "print \"Critical current is : %0.3f\"%(Ic),\" A\" "
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Critical current is : 24.819  A\n"
+       ]
+      }
+     ],
+     "prompt_number": 72
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa2.36 page 79"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "#given data\n",
+      "Hc_0=8*10**4 #in A/m\n",
+      "Tc=7.2 #in K\n",
+      "T=4.5 #in K\n",
+      "d=1 #in mm\n",
+      "r=d/2 #in mm\n",
+      "r=r*10**-3 #in m\n",
+      "Hc=Hc_0*(1-(T/Tc)**2)\n",
+      "print \"The critical field at T=4.5 K is : %0.3e\"%(Hc),\" A/m\" \n",
+      "Ic=2*pi*r*Hc \n",
+      "print \"Critical current is : %0.2f\"%(Ic),\" A\" "
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "The critical field at T=4.5 K is : 4.875e+04  A/m\n",
+        "Critical current is : 153.15  A\n"
+       ]
+      }
+     ],
+     "prompt_number": 73
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa2.37 page 86"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "from math import sqrt\n",
+      "# Formula R=rho*l/a\n",
+      "#putting value for copper wire\n",
+      "R=2 # in ohm\n",
+      "l=100 #in meter\n",
+      "rho=1.7*10**-8 # (for copper)\n",
+      "a=rho*l/R #in meter\n",
+      "a=a*10**6 # in mm\n",
+      "# Formula a=pi/4*d**2\n",
+      "d_copper=sqrt(a*4/pi)  #  (d_copper is diameter for copper)\n",
+      "\n",
+      "# Formula R=rho*l/a\n",
+      "#putting value for Aluminium wire\n",
+      "R=2 # in ohm\n",
+      "l=100 #in meter\n",
+      "rho=2.8*10**-8 # (for aluminium)\n",
+      "a=rho*l/R #in meter\n",
+      "a=a*10**6 # in mm\n",
+      "# Formula a=pi/4*d**2\n",
+      "d_aluminium=sqrt(a*4/pi)  #  (d_aluminium is diameter for aluminium)\n",
+      "DiaRatio=d_aluminium/d_copper  #  (DiaRatio is ratio of diameter of aluminium and copper)\n",
+      "print \"The diameter of the aluminium wire is \",round(DiaRatio,2),\" times that of copper wire\" "
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "The diameter of the aluminium wire is  1.28  times that of copper wire\n"
+       ]
+      }
+     ],
+     "prompt_number": 74
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa2.38 page 99"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "from math import log\n",
+      "#given data\n",
+      "l=60 # in cm\n",
+      "l=l*10**-2 #in meter\n",
+      "d=20 # in cm \n",
+      "d=d*10**-2 #in meter\n",
+      "D=35 # in cm \n",
+      "D=D*10**-2 #in meter\n",
+      "r1=d/2 \n",
+      "r2=D/2 \n",
+      "rho=8000 # in ohm-cm\n",
+      "rho=80 # in ohm-m\n",
+      "# Let Insulation resistance of the liquid resistor = Ir\n",
+      "Ir=(rho/(2*pi*l))*log(r2/r1) \n",
+      "print \" Insulation resistance of the liquid resistor is : \",round(Ir,2),\" ohm\""
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        " Insulation resistance of the liquid resistor is :  11.88  ohm\n"
+       ]
+      }
+     ],
+     "prompt_number": 75
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa2.39 page 100"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "#given data\n",
+      "R_desh=1820 # in M ohm\n",
+      "R_desh=R_desh*10**6 # in ohm\n",
+      "d1=1.5 # in cm\n",
+      "d1=d1*10**-2 # in meter\n",
+      "d2=5 # in cm\n",
+      "d2=d2*10**-2 # in meter\n",
+      "l=3000 # in meter\n",
+      "r1=d1/2 \n",
+      "r2=d2/2 \n",
+      "\n",
+      "rho= (2*pi*l*R_desh)/log(r2/r1) \n",
+      "print \"Resistivity of dielectric is : %0.2e\"%(rho),\" ohm meter\""
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Resistivity of dielectric is : 2.85e+13  ohm meter\n"
+       ]
+      }
+     ],
+     "prompt_number": 76
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa2.40 page 100"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "# given data\n",
+      "# First Case:\n",
+      "r1=1.5/2 # in cm\n",
+      "# let radius thickness of insulation = r1_t\n",
+      "r1_t=1.5 # in cm\n",
+      "r2=r1+r1_t \n",
+      "R_desh=500 # in M ohm\n",
+      "R_desh=R_desh*10**6 # in ohm\n",
+      "# Second case:\n",
+      "r1_desh=r1 # in cm (as before)\n",
+      "# let radius thickness of insulation = r2_t\n",
+      "r2_t=2.5 # in cm\n",
+      "r2_desh=r1+r2_t \n",
+      "# since Insulation resistance , R_desh= sigma/(2*pi*l)*log(r2/r1) and\n",
+      "#                               R1_desh= sigma/(2*pi*l)*log(r2_desh/r1_desh)\n",
+      "# Dividing R1_desh by R1, We get\n",
+      "# R1_desh/R_desh = log(r2_desh/r1_desh)/log(r2/r1)\n",
+      "# Let R = R1_desh/R_desh, Now\n",
+      "R= log(r2_desh/r1_desh)/log(r2/r1) \n",
+      "R1_desh=R*R_desh \n",
+      "print \"New insulation resistance is : \",round(R1_desh*10**-6,2),\" M ohm\" "
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "New insulation resistance is :  667.36  M ohm\n"
+       ]
+      }
+     ],
+     "prompt_number": 77
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa2.41 page 101"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "from math import exp\n",
+      "\n",
+      "# given data\n",
+      "t1=20 # in degree C\n",
+      "t2=36 # in degree C\n",
+      "alpha_20=0.0043 # in per degree C  (Temperature Coefficient)\n",
+      "InsulationResistance=480*10**6 # in ohm\n",
+      "copper_cond_res=0.7 # in ohm  (copper conductor resistance)\n",
+      "l=500*10**-3 # in kilo meter (length)\n",
+      "R1_desh=InsulationResistance * l # in ohm\n",
+      "\n",
+      "# From Formula log(R2_desh)= log(R1_desh-K*(t2-t1))\n",
+      "# K= 1/(t2-t1)*log(R1_desh/R2_desh)\n",
+      "# since when t2-t1=10 degree C and R1_desh/R2_desh= 2\n",
+      "\n",
+      "K=1/10*log(2) \n",
+      "\n",
+      "# (i) Insulation resistance at any temperature t2, R2_desh is given by\n",
+      "logR2_desh= log(R1_desh)-(t2-t1)/10* log(2) \n",
+      "R2_desh= exp(logR2_desh)\n",
+      "  \n",
+      "print \"(i) Insulation resistance at any temperature : \",round(R2_desh*10**-6,2),\" Mega ohm\" \n",
+      "  \n",
+      "# (ii) \n",
+      "R_20= copper_cond_res/l # in ohm\n",
+      "R_36=R_20*(1+alpha_20*(t2-t1))\n",
+      "    \n",
+      "print \"(ii) Resistance at 36 degree C is : \",(R_36),\" ohm\"\n",
+      "    "
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "(i) Insulation resistance at any temperature :  79.17  Mega ohm\n",
+        "(ii) Resistance at 36 degree C is :  1.49632  ohm\n"
+       ]
+      }
+     ],
+     "prompt_number": 78
+    }
+   ],
+   "metadata": {}
+  }
+ ]
+}
\ No newline at end of file
diff --git a/Electrical_And_Electronics_Engineering_Materials_by_J._B._Gupta/chap3.ipynb b/Electrical_And_Electronics_Engineering_Materials_by_J._B._Gupta/chap3.ipynb
new file mode 100644
index 00000000..69d038e9
--- /dev/null
+++ b/Electrical_And_Electronics_Engineering_Materials_by_J._B._Gupta/chap3.ipynb
@@ -0,0 +1,1142 @@
+{
+ "metadata": {
+  "name": "",
+  "signature": "sha256:a96bbbdccc6f55b0164bcf77a9bc387adedc3a678279c448dfc55de8004bfc24"
+ },
+ "nbformat": 3,
+ "nbformat_minor": 0,
+ "worksheets": [
+  {
+   "cells": [
+    {
+     "cell_type": "heading",
+     "level": 1,
+     "metadata": {},
+     "source": [
+      "Chapter 3 - Semiconductors"
+     ]
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa3.1 page 127"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "from __future__ import division\n",
+      "from math import sqrt\n",
+      "# given data\n",
+      "E=2.1 #in eV\n",
+      "E=E*1.602*10**-19 # in J\n",
+      "m=9.107*10**-31 # in kg (mass of electron)\n",
+      "# Formula E=1/2*m*v**2\n",
+      "v=sqrt(2*E/m) \n",
+      "print \" Velocity of electron at Fermi-level is : %0.1e\"%(v),\" m/s\""
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        " Velocity of electron at Fermi-level is : 8.6e+05  m/s\n"
+       ]
+      }
+     ],
+     "prompt_number": 1
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa3.2 page 127"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "# given data\n",
+      "E=5.5 # in eV  (Fermi energy)\n",
+      "E=E*1.6*10**-19 # in J \n",
+      "miu_e=7.04*10**-3  #in m**2/V-s  (Mobility of electrons)\n",
+      "n=5.8*10**28   # in /m**3   (Number of conduction electrons/m**3)\n",
+      "e=1.6*10**-19  # in coulomb\n",
+      "m=9.1*10**-31 #in kg\n",
+      "#(i) Relaxation time,\n",
+      "tau=miu_e/e*m \n",
+      "print \"(i) Relaxation time is : \",(tau),\" second\" \n",
+      "sigma=(n*e*miu_e) \n",
+      "#(ii) Resistivity of conductor,\n",
+      "rho=1/sigma \n",
+      "print \"(ii) Resistivity of conductor is : %0.2e\"%(rho),\" ohm-meter\" \n",
+      "# (iii) Let Velocity of electrons with fermi energy = v\n",
+      "v=sqrt(2*E/m) \n",
+      "print \"(iii) Velocity of electron with Fermi-level is : %0.4e\"%(v),\" m/s\" "
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "(i) Relaxation time is :  4.004e-14  second\n",
+        "(ii) Resistivity of conductor is : 1.53e-08  ohm-meter\n",
+        "(iii) Velocity of electron with Fermi-level is : 1.3907e+06  m/s\n"
+       ]
+      }
+     ],
+     "prompt_number": 2
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa3.3 page 132"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "# given data\n",
+      "n_i=2.5*10**13 # in /cm**3\n",
+      "rho=0.039 # in ohm-cm\n",
+      "sigma_n=1/rho \n",
+      "e=1.602*10**-19 # in C\n",
+      "miu_e=3600 # in cm**2/V-s\n",
+      "#since sigma_n = n*e*miu_e = N_D*e*miu_e\n",
+      "N_D=sigma_n/(e*miu_e) \n",
+      "n=N_D # (approx)\n",
+      "print \"Concentration of electrons is : %0.2e\"%(n),\" /cm**3\" \n",
+      "p=n_i**2/n \n",
+      "print \"Concentration of holes is : %0.1e\"%(p),\" /cm**3\" "
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Concentration of electrons is : 4.45e+16  /cm**3\n",
+        "Concentration of holes is : 1.4e+10  /cm**3\n"
+       ]
+      }
+     ],
+     "prompt_number": 3
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa3.4 page 133"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "from __future__ import division\n",
+      "# given data\n",
+      "SiliconAtom=5*10**22 # unit less (Number of silicon atom)\n",
+      "DonorImpurity=1/10**6 \n",
+      "n_i=1.45*10**10 # in cm**-3\n",
+      "e=1.602*10**-19 # in C\n",
+      "miu_e=1300 # taking miu_e for Si as 1300 cm**2/V-s\n",
+      "# (i) Donor atom concentraion\n",
+      "# Formula N_D= Number of silicon atoms/cm**3 * donor impurity\n",
+      "N_D=SiliconAtom*DonorImpurity \n",
+      "print \"(i) Donor atom concentration is : \",(N_D),\" per cm**3\" \n",
+      "\n",
+      "# (ii) Mobile electron concentration\n",
+      "n=N_D  # (approx.)\n",
+      "print \"(ii) Mobile electron concentration is : \",(n),\" per cm**3\" \n",
+      "\n",
+      "# (iii) Hole concentration\n",
+      "p=n_i**2/N_D \n",
+      "print \"(iii) Hole concentration is : %0.3e\"%(p),\" /cm**3\" \n",
+      "\n",
+      "#(iv) conductivity of doped silicon sample\n",
+      "sigma=n*e*miu_e \n",
+      "print \"(iv) conductivity of doped silicon sample is : \",(sigma),\" S/cm\" \n",
+      "\n",
+      "rho=1/sigma \n",
+      "#(v) resistance of given semiconductor\n",
+      "l=0.5 # in cm\n",
+      "a=(50*10**-4)**2\n",
+      "R=rho*l/a \n",
+      "print \"(v) Resistance of give semiconductor is : %0.f\"%(R),\" ohm\" "
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "(i) Donor atom concentration is :  5e+16  per cm**3\n",
+        "(ii) Mobile electron concentration is :  5e+16  per cm**3\n",
+        "(iii) Hole concentration is : 4.205e+03  /cm**3\n",
+        "(iv) conductivity of doped silicon sample is :  10.413  S/cm\n",
+        "(v) Resistance of give semiconductor is : 1921  ohm\n"
+       ]
+      }
+     ],
+     "prompt_number": 4
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa3.5 page 133"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "# given data\n",
+      "n_i=1.4*10**18 # in m**3\n",
+      "N_D=1.4*10**24 # in m**3\n",
+      "n=N_D # (approx)\n",
+      "p=n_i**2/n \n",
+      "# let Ratio of electron to hole concentration = r\n",
+      "r=n/p \n",
+      "print \"Ratio of electron to hole concentration is : \",(r)"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Ratio of electron to hole concentration is :  1e+12\n"
+       ]
+      }
+     ],
+     "prompt_number": 5
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa3.6 page 138"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "# given data\n",
+      "n_i=2.5*10**13 # in cm**3\n",
+      "e=1.6*10**-19 # in coulomb\n",
+      "miu_h=1800 # in cm**2/V-s\n",
+      "miu_e=3800 # in cm**2/V-s\n",
+      "sigma_i=n_i*e*(miu_e+miu_h) \n",
+      "print \"Intrinsic conductivity is : \",(sigma_i),\" /ohm-cm\" \n",
+      "rho_i=1/sigma_i \n",
+      "print \"Intrinsic resistiviry is : %0.2f\"%(rho_i),\" ohm-cm\""
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Intrinsic conductivity is :  0.0224  /ohm-cm\n",
+        "Intrinsic resistiviry is : 44.64  ohm-cm\n"
+       ]
+      }
+     ],
+     "prompt_number": 6
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa3.7 page 138"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "# given data\n",
+      "rho_i=0.47 # in ohm-meter\n",
+      "sigma_i=1/rho_i \n",
+      "miu_e=0.39 # in m**2/V-s\n",
+      "miu_h=0.19 # in m**2/V-s\n",
+      "e=1.6*10**-19 # in C\n",
+      "\n",
+      "# since sigma_i=n_i*e*(miu_e+miu_h) \n",
+      "n_i=sigma_i/(e*(miu_e+miu_h)) \n",
+      "# so Density of electrons = Intrinsic Concentration,n_i\n",
+      "print \"Density of electons is : %0.3e\"%(n_i),\" /m**3\" \n",
+      "E=10**4 # in V/m\n",
+      "v_n=miu_e*E \n",
+      "print \"Drift velocity of electrons is : \",(v_n),\" m/s\" \n",
+      "v_h=miu_h*E \n",
+      "print \"Drift velocity of holes is : \",(v_h),\" m/s\" "
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Density of electons is : 2.293e+19  /m**3\n",
+        "Drift velocity of electrons is :  3900.0  m/s\n",
+        "Drift velocity of holes is :  1900.0  m/s\n"
+       ]
+      }
+     ],
+     "prompt_number": 7
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa3.8 page 138"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "# given data\n",
+      "n_i=1.5*10**10 # in /cm**3\n",
+      "miu_e=1300 # in cm**2/V-s\n",
+      "miu_h=450 # in cm**2/V-s\n",
+      "e=1.6*10**-19 # in C  (charge of electrons)\n",
+      "sigma_i=n_i*e*(miu_e+miu_h) \n",
+      "print \"Conductivity of silicon (intrinsic) is : \",(sigma_i),\" /ohm-cm\" \n",
+      "N_A=10**18 # in /cm**3\n",
+      "print \"conductivity of the resulting P-type silicon semiconductor\"\n",
+      "sigma_p=e*N_A*miu_h \n",
+      "print (sigma_p),\" /ohm-cm\" "
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Conductivity of silicon (intrinsic) is :  4.2e-06  /ohm-cm\n",
+        "conductivity of the resulting P-type silicon semiconductor\n",
+        "72.0  /ohm-cm\n"
+       ]
+      }
+     ],
+     "prompt_number": 8
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa3.9 page 139"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "# given data\n",
+      "n_i=2.5*10**13 # in /m**3\n",
+      "miu_e=3800 # in cm**2/V-s\n",
+      "miu_h=1800 # in cm**2/V-s\n",
+      "e=1.6*10**-19 # in C  (charge of electrons)\n",
+      "sigma_i=n_i*e*(miu_e+miu_h) \n",
+      "print \"Intrinsic conductivity is : \",(sigma_i),\" /ohm-cm\" \n",
+      "# Let Number of germanium atoms/cm**3 = no_g\n",
+      "no_g=4.41*10**22 \n",
+      "# since Donor impurity = 1 donor atom / 10**7 germanium atoms, so \n",
+      "DonorImpurity=10**-7 \n",
+      "N_D=no_g*DonorImpurity \n",
+      "n=N_D  # (approx)\n",
+      "p=n_i**2/N_D \n",
+      "# so\n",
+      "sigma_n=e*N_D*miu_e \n",
+      "print \"conductivity in N-type germanium semiconductor is : %0.2f\"%(sigma_n),\" /ohm-cm\" "
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Intrinsic conductivity is :  0.0224  /ohm-cm\n",
+        "conductivity in N-type germanium semiconductor is : 2.68  /ohm-cm\n"
+       ]
+      }
+     ],
+     "prompt_number": 9
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa3.10 page 139"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "# given data\n",
+      "e=1.6*10**-19 #in C\n",
+      "miu_e=.38 # in m**2/V-s\n",
+      "miu_h=.18 # in m**2/V-s\n",
+      "l=25 # in mm (length)\n",
+      "l=l*10**-3 # in m \n",
+      "w=4 # in mm (width)\n",
+      "w=w*10**-3 # in m\n",
+      "t=1.5 # in mm (thickness)\n",
+      "t=t*10**-3 # in m\n",
+      "V=10 # in V\n",
+      "l=25 # in mm\n",
+      "l=l*10**-3 #in m\n",
+      "E=V/l \n",
+      "#(i) \n",
+      "v_e=miu_e*E \n",
+      "v_h=miu_h*E \n",
+      "print \"Electron drift velocity is : \",(v_e),\" m/s\" \n",
+      "print \"Hole drift velocity is : \",(v_h),\" m/s\" \n",
+      "n_i=2.5*10**19 #in /m**3\n",
+      "#(ii)\n",
+      "sigma_i=n_i*e*(miu_e+miu_h) \n",
+      "print \"Intrinsic conductiviry of Ge is : \",(sigma_i),\" /ohm-cm\" \n",
+      "#(iii)\n",
+      "a=w*t \n",
+      "I=sigma_i*E*a # in amp\n",
+      "I=I*10**3 # in m A\n",
+      "print \"Total current is : \",(I),\" mA\" "
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Electron drift velocity is :  152.0  m/s\n",
+        "Hole drift velocity is :  72.0  m/s\n",
+        "Intrinsic conductiviry of Ge is :  2.24  /ohm-cm\n",
+        "Total current is :  5.376  mA\n"
+       ]
+      }
+     ],
+     "prompt_number": 10
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa3.11 page 139"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "# given data\n",
+      "k_desh=1.38*10**-23 # in J degree**-1\n",
+      "e=1.602*10**-19 # in C\n",
+      "miu_e=3600 # in cm**2/V-s\n",
+      "miu_h=1700 # in cm**2/V-s\n",
+      "T=300 # in K\n",
+      "D_e=miu_e*k_desh*T/e \n",
+      "print \"Diffusion constant of electrons is : %0.f\"%(D_e),\" cm**2/s\" \n",
+      "D_h=miu_h*k_desh*T/e \n",
+      "print \"Diffusion constant of holes is : %0.2f\"%(D_h),\" cm**2/s\" "
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Diffusion constant of electrons is : 93  cm**2/s\n",
+        "Diffusion constant of holes is : 43.93  cm**2/s\n"
+       ]
+      }
+     ],
+     "prompt_number": 11
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa3.12 page 143"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "# given data\n",
+      "e=1.6*10**-19 # in coulomb\n",
+      "Resistivity=9*10**-3 # in ohm-m\n",
+      "R_H=3.6*10**-4 # in m**3 coulomb**-1  (Hall Coefficient)\n",
+      "sigma=1/Resistivity \n",
+      "rho=1/R_H \n",
+      "n=rho/e \n",
+      "print \"Density of charge carriers is : %0.5e\"%(n),\" /m^3\" \n",
+      "miu=sigma*R_H \n",
+      "print \"Mobility is : \",(miu),\" m^2/V-s\" "
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Density of charge carriers is : 1.73611e+22  /m^3\n",
+        "Mobility is :  0.04  m^2/V-s\n"
+       ]
+      }
+     ],
+     "prompt_number": 12
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa3.13 page 143"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "# given data\n",
+      "E_x=100 # in V/m\n",
+      "e=1.6*10**-19 # in C\n",
+      "R_H=0.0145 # in m**3/coulomb\n",
+      "miu_n=0.36 # in m**2/volt-second\n",
+      "# Formula R_H=1/(n*e)\n",
+      "n=1/(R_H*e) \n",
+      "sigma=n*e*miu_n \n",
+      "J=sigma*E_x \n",
+      "print \"Current density is : %0.f\"%(J),\" A per m**2\" "
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Current density is : 2483  A per m**2\n"
+       ]
+      }
+     ],
+     "prompt_number": 13
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa3.14 page 144"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "# given data\n",
+      "Resistivity=9 # in milli-ohm-m\n",
+      "Resistivity=9*10**-3 # in ohm-m\n",
+      "miu=0.03 # in m**2/V-s\n",
+      "sigma=1/Resistivity \n",
+      "R_H=miu/sigma \n",
+      "print \"Half coefficient is : %0.1e\"%(R_H),\" m**3/C\" "
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Half coefficient is : 2.7e-04  m**3/C\n"
+       ]
+      }
+     ],
+     "prompt_number": 14
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa3.15 page 144"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "# given data\n",
+      "E_x=5 # in V/cm\n",
+      "miu_e=3800 # in cm**2/V-s\n",
+      "B_z=0.1 # in Wb/m**2\n",
+      "d=4 # in mm\n",
+      "d=d*10**-3 # in m\n",
+      "v=miu_e*E_x #in cm/second\n",
+      "v=v*10**-2 # in m/second\n",
+      "V_H=B_z*v*d # in V\n",
+      "V_H=V_H*10**3 # in m V\n",
+      "print \"Hall voltage is : \",(V_H),\" mV\" "
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Hall voltage is :  76.0  mV\n"
+       ]
+      }
+     ],
+     "prompt_number": 15
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa3.16 page 144"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "# given data\n",
+      "rho=200 # in Kilo ohm-cm\n",
+      "rho=rho*10**-2 # in kilo ohm m\n",
+      "rho=rho*10**3 # in ohm meter\n",
+      "sigma=1/rho \n",
+      "V_H=50 # in mV\n",
+      "V_H=V_H*10**-3 #in V\n",
+      "I=10 # in miu A\n",
+      "I=I*10**-6 #in A\n",
+      "B_z=0.1 # in Wb/m**2\n",
+      "w=3 #in mm\n",
+      "w=w*10**-3 #in meter\n",
+      "R_H=V_H*w/(B_z*I) \n",
+      "print \"Mobility of holes in p-type silicon bar is : \"\n",
+      "miu_h=sigma*R_H \n",
+      "print str(miu_h),\" m**2/V-s\" "
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Mobility of holes in p-type silicon bar is : \n",
+        "0.075  m**2/V-s\n"
+       ]
+      }
+     ],
+     "prompt_number": 16
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa3.17 page 144"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "# given data\n",
+      "N_D=1*10**21 # in /m**3\n",
+      "B_Z=0.2 # in T\n",
+      "J=600 # in A/m**2\n",
+      "n=N_D \n",
+      "d=4 #in mm\n",
+      "d=d*10**-3 # in meterr\n",
+      "e=1.6*10**-19 # in C  (electron charge)\n",
+      "# Formula  V_H*w/(B_Z*I) = 1/(n*e) , hence V_H=B_Z*I/(n*e*w)\n",
+      "# where I=J*w*d\n",
+      "# putting I=J*w*d in V_H=B_Z*I/(n*e*w), we get\n",
+      "V_H=B_Z*J*d/(n*e) # in V\n",
+      "V_H=V_H*10**3 # in mV\n",
+      "print \"Hall Voltage is : \",(V_H),\" mV\" "
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Hall Voltage is :  3.0  mV\n"
+       ]
+      }
+     ],
+     "prompt_number": 17
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa3.18 page 145"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "# given data\n",
+      "w=0.1 # in mm\n",
+      "B_Z=0.6 # in T\n",
+      "R_H=3.8*10**-4 # in m**3/C\n",
+      "I=10 # in mA\n",
+      "I=I*10**-3 #in A\n",
+      "V_H=R_H*B_Z*I/w # in V\n",
+      "V_H=V_H*10**6 # in V\n",
+      "print \"Hall voltage is : \",(V_H),\" micro volt\" "
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Hall voltage is :  22.8  micro volt\n"
+       ]
+      }
+     ],
+     "prompt_number": 18
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa3.19 page 145"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "# given data\n",
+      "Resistivity=9.23*10**-3 # in ohm-m\n",
+      "R_H=3.84*10**-4 #in m**3/C   (Hall Coefficient)\n",
+      "sigma=1/Resistivity \n",
+      "rho=1/R_H \n",
+      "e=1.6*10**-19 # in C (electron charge)\n",
+      "n=rho/e \n",
+      "print \"Density of charge carriers is : %0.3e\"%(n),\" /m**2\" \n",
+      "miu=sigma*R_H \n",
+      "print \"Mobility is : \",round(miu,4),\" m**2/V-s\""
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Density of charge carriers is : 1.628e+22  /m**2\n",
+        "Mobility is :  0.0416  m**2/V-s\n"
+       ]
+      }
+     ],
+     "prompt_number": 19
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa3.20 page 145"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "from math import atan, degrees\n",
+      "# given data\n",
+      "B=0.48 # in Wb/m**2\n",
+      "R_H=3.55*10**-4 # in m**3/C\n",
+      "Resistivity=.00912 # in ohm\n",
+      "sigma=1/Resistivity \n",
+      "theta_H=degrees(atan(sigma*B*R_H) )\n",
+      "print \"Hall angle is : \",round(theta_H,4),\" degree\""
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Hall angle is :  1.0704  degree\n"
+       ]
+      }
+     ],
+     "prompt_number": 20
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa3.21 page 154"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "# given data\n",
+      "T=27 # in degree C\n",
+      "T=T+273 # in K\n",
+      "# Let E_C - E_F =E_CF\n",
+      "E_CF=0.3 # in eV\n",
+      "# Formula E_C - E_F = k*T*log(n_C/N_D)\n",
+      "# Let log(n_C/N_D) = L, so\n",
+      "L=E_CF/T \n",
+      "T_desh=55 # in degree C\n",
+      "T_desh=T_desh+273 # in K\n",
+      "#At temperature T_desh\n",
+      "new_fermi_level= T_desh*L   # where L=log(n_C/N_D)\n",
+      "print \"The new position of Fermi Level is : \",(new_fermi_level),\" V\" "
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "The new position of Fermi Level is :  0.328  V\n"
+       ]
+      }
+     ],
+     "prompt_number": 21
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa3.22 page 154"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "from math import log\n",
+      "# given data\n",
+      "N_A=8*10**14 # in /cm**3\n",
+      "N_D=N_A \n",
+      "n_i=2*10**13 # in /cm**3\n",
+      "k=8.61*10**-5 # in eV/K\n",
+      "T=300 # in K\n",
+      "V_0=k*T*log(N_D*N_A/n_i**2) \n",
+      "print \"Potential barrier is : %0.2f\"%(V_0),\" V\" "
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Potential barrier is : 0.19  V\n"
+       ]
+      }
+     ],
+     "prompt_number": 22
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa3.23 page 155"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "# given data\n",
+      "# (i) when\n",
+      "I_D=2 # in mA\n",
+      "I_D=I_D*10**-3 # in A\n",
+      "V_D=0.5 # in V\n",
+      "R1=V_D/I_D \n",
+      "print \"Resistace is : \",(R1),\" ohm\" \n",
+      "# (ii) when\n",
+      "I_D=20 # in mA\n",
+      "I_D=I_D*10**-3 # in A\n",
+      "V_D=0.8 # in V\n",
+      "R2=V_D/I_D \n",
+      "print \"Resistace is : \",(R2),\" ohm\" \n",
+      "# (ii) when\n",
+      "I_D=-1 # in miu A\n",
+      "I_D=I_D*10**-6 # in A\n",
+      "V_D=-10 # in V\n",
+      "R3=V_D/I_D # in ohm\n",
+      "R3=R3*10**-6 # in M ohm\n",
+      "print \"Resistace is : \",(R3),\" M ohm\" "
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Resistace is :  250.0  ohm\n",
+        "Resistace is :  40.0  ohm\n",
+        "Resistace is :  10.0  M ohm\n"
+       ]
+      }
+     ],
+     "prompt_number": 23
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa3.24 page 155"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "from math import exp\n",
+      "# given data\n",
+      "E_G=0.72 # in eV\n",
+      "E_F=E_G/2 # in eV\n",
+      "k=8.61*10**-5  # in eV/K\n",
+      "T=300 # in K\n",
+      "# Formula n_C/n = 1/1+%e**(E_G-E_F)/k*T\n",
+      "# Let n_C/n = N\n",
+      "N=1/(1+exp((E_G-E_F)/(k*T))) \n",
+      "\n",
+      "print \"Fraction of the total number of electrons (conduction band as well as valence band) : %0.2e\"%(N)"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Fraction of the total number of electrons (conduction band as well as valence band) : 8.85e-07\n"
+       ]
+      }
+     ],
+     "prompt_number": 24
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa3.25 page 160"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "# given data\n",
+      "I_0=.15 # in micro amp\n",
+      "I_0=I_0*10**-6 # in A\n",
+      "V=0.12 # in V\n",
+      "V_T=26 # in mV\n",
+      "V_T=V_T*10**-3 # in V\n",
+      "I=I_0*(exp(V/V_T)-1) # in amp\n",
+      "I=I*10**6 # in micro amp\n",
+      "print \"Large reverse bias current is : %0.f\"%(I),\" micro amp\" "
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Large reverse bias current is : 15  micro amp\n"
+       ]
+      }
+     ],
+     "prompt_number": 25
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa3.26 page 160"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "# given data\n",
+      "I=.01 # in A\n",
+      "I_0=2.5*10**-6 # in  amp\n",
+      "nita=2 # for silicon\n",
+      "V_T=26 # in mV\n",
+      "V_T=V_T*10**-3 # in V\n",
+      "# Formula I=I_0*(%e**(V/(nita*V_T))-1) \n",
+      "V=nita*V_T*log(I/I_0+1) \n",
+      "print \"Forward voltage is : %0.2f\"%(V),\" V\"   "
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Forward voltage is : 0.43  V\n"
+       ]
+      }
+     ],
+     "prompt_number": 26
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa3.27 page 160"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "# given data\n",
+      "N_D=10**21 # in m**-3\n",
+      "N_A=10**22 # in m**-3\n",
+      "D_e=3.4*10**-3 # in m**2/s\n",
+      "D_h=1.2*10**-3 # in m**2/s\n",
+      "L_e=7.1*10**-4 # in m\n",
+      "L_h=3.5*10**-4 # in m\n",
+      "n_i=1.602*10**16 # in /m**3\n",
+      "e=1.6*10**-19 # in C (electron charge)\n",
+      "# Formula  I_0=a*e*[D_h/(L_h*N_D) + D_e/(L_e*N_A)]*n_i**2\n",
+      "#and\n",
+      "# Reverse saturation current density = I_0/a = [D_h/(L_h*N_D) + D_e/(L_e*N_A)]*e*n_i**2 , So\n",
+      "CurrentDensity= (D_h/(L_h*N_D) + D_e/(L_e*N_A))*e*n_i**2 # in A\n",
+      "CurrentDensity=CurrentDensity*10**6 # in micro A\n",
+      "print \"Reverse saturation current density is : %0.2f\"%(CurrentDensity),\"  micro amp\" "
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Reverse saturation current density is : 0.16   micro amp\n"
+       ]
+      }
+     ],
+     "prompt_number": 27
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa3.28 page 163"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "# given data'\n",
+      "N_D=10**17*10**6 # in m**-3\n",
+      "N_A=0.5*10**16*10**6 # in atoms/m**3\n",
+      "epsilon_r=10 # in F/m\n",
+      "epsilon_o=8.85*10**-12 # in F/m\n",
+      "epsilon=epsilon_r*epsilon_o \n",
+      "e=1.602*10**-19 # in C (electron charge)\n",
+      "# (i) when no external voltage is applied i.e.\n",
+      "V=0 \n",
+      "V_B=0.7 # in V\n",
+      "W=sqrt(2*epsilon*V_B/e*(1/N_A+1/N_D)) \n",
+      "print \"Junction width is : %0.3e\"%(W),\" m\" \n",
+      "# (ii) when external voltage of -10 V is applied i.e.\n",
+      "V=-10 # in V\n",
+      "V_o=0.7 # in V\n",
+      "V_B=V_o-V \n",
+      "W=sqrt(2*epsilon*V_B/e*(1/N_A+1/N_D)) \n",
+      "print \"Junction width is : %0.3e\"%(W),\" m\" \n",
+      "\n",
+      "# Note: Answer in the book is wrong"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Junction width is : 4.030e-07  m\n",
+        "Junction width is : 1.576e-06  m\n"
+       ]
+      }
+     ],
+     "prompt_number": 28
+    }
+   ],
+   "metadata": {}
+  }
+ ]
+}
\ No newline at end of file
diff --git a/Electrical_And_Electronics_Engineering_Materials_by_J._B._Gupta/chap4.ipynb b/Electrical_And_Electronics_Engineering_Materials_by_J._B._Gupta/chap4.ipynb
new file mode 100644
index 00000000..27cf230e
--- /dev/null
+++ b/Electrical_And_Electronics_Engineering_Materials_by_J._B._Gupta/chap4.ipynb
@@ -0,0 +1,439 @@
+{
+ "metadata": {
+  "name": "",
+  "signature": "sha256:c1260907a128bcdd9e68ce2295ce1e28beeee0ab6e7ba3bfd49dd804d883442b"
+ },
+ "nbformat": 3,
+ "nbformat_minor": 0,
+ "worksheets": [
+  {
+   "cells": [
+    {
+     "cell_type": "heading",
+     "level": 1,
+     "metadata": {},
+     "source": [
+      "Chapter 4 - Biolar junction & Field Effect Transistors"
+     ]
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa 4.1 page 195"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "#given data :\n",
+      "VGS=10 #in Volt\n",
+      "IG=0.001 #in uAmpere\n",
+      "IG=IG*10**-6 #in Ampere\n",
+      "RGS=VGS/IG #in Ohm\n",
+      "print \"Resistance between gate and source = %0.2f Mohm \"%(RGS*10**-6) "
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Resistance between gate and source = 10000.00 Mohm \n"
+       ]
+      }
+     ],
+     "prompt_number": 1
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa 4.2 page 195"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "#given data :\n",
+      "delVDS=1.5 #in Volt\n",
+      "delID=120 #in uAmpere\n",
+      "delID=delID*10**-6 #in Ampere\n",
+      "rd=delVDS/delID #in Ohm\n",
+      "print \"AC drain Resistance of JFET = %0.2f kohm\"%(rd*10**-3)"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "AC drain Resistance of JFET = 12.50 kohm\n"
+       ]
+      }
+     ],
+     "prompt_number": 2
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa 4.3 page 195"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "#given data :\n",
+      "ID2=1.5 #in mAmpere\n",
+      "ID1=1.2 #in mAmpere\n",
+      "delID=ID2-ID1 #in Ampere\n",
+      "VGS1=-4.25 #in Volt\n",
+      "VGS2=-4.10 #in Volt\n",
+      "delVGS=VGS2-VGS1 #in Volt\n",
+      "gm=delID/delVGS #in Ohm\n",
+      "print \"Transconductance = %0.2f mA/V \"%gm \n",
+      "print \"Transconductance = %0.2f uS \"%(gm*10**3) "
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Transconductance = 2.00 mA/V \n",
+        "Transconductance = 2000.00 uS \n"
+       ]
+      }
+     ],
+     "prompt_number": 3
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa 4.4 page 195"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "#given data :\n",
+      "VDS1=5 #in Volt\n",
+      "VDS2=12 #in Volt\n",
+      "VDS3=12 #in Volt\n",
+      "VGS1=0 #in Volt\n",
+      "VGS2=0 #in Volt\n",
+      "VGS3=-0.25 #in Volt\n",
+      "ID1=8 #in mAmpere\n",
+      "ID2=8.2 #in mAmpere\n",
+      "ID3=7.5 #in mAmpere\n",
+      "#AC drain resistance\n",
+      "delVDS=VDS2-VDS1 #in Volt\n",
+      "delID=ID2-ID1 #in mAmpere\n",
+      "rd=delVDS/delID #in Kohm\n",
+      "print \"AC Drain resistance = %0.2f kohm \"%(rd) \n",
+      "#Transconductance\n",
+      "delID=ID3-ID2 #in mAmpere\n",
+      "delVGS=VGS3-VGS2 #in Volt\n",
+      "gm=delID/delVGS #in mA/V or mS\n",
+      "print \"Transconductance = %0.2f mA/V  \"%gm \n",
+      "#Amplification Factor\n",
+      "meu=rd*1000*gm*10**-3 #unitless\n",
+      "print \"Amplification Factor : \" ,meu"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "AC Drain resistance = 35.00 kohm \n",
+        "Transconductance = 2.80 mA/V  \n",
+        "Amplification Factor :  98.0\n"
+       ]
+      }
+     ],
+     "prompt_number": 4
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa 4.5 page 196"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "from math import sqrt\n",
+      "#given data :\n",
+      "VP=-4.5 #in Volt\n",
+      "IDSS=10 #in mAmpere\n",
+      "IDS=2.5 #in mAmpere\n",
+      "#Formula : IDS=IDSS*[1-VGS/VP]**2\n",
+      "VGS=VP*(1-sqrt(IDS/IDSS)) #in Volt\n",
+      "gm=(-2*IDSS*10**-3)*(1-VGS/VP)/VP #in mA/V or mS\n",
+      "print \"Transconductance = %0.2f mA/V \"%(gm*1000) "
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Transconductance = 2.22 mA/V \n"
+       ]
+      }
+     ],
+     "prompt_number": 5
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa 4.6 page 196"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "#given data :\n",
+      "gm=10 #in mS\n",
+      "gm=gm*10**-3 #in S\n",
+      "IDSS=10 #in uAmpere\n",
+      "IDSS=IDSS*10**-6 #in Ampere\n",
+      "#VGS(OFF):VGS=VP\n",
+      "#Formula : gm=gmo=-2*IDSS/VP=-2*IDSS/VG(Off)\n",
+      "VGS_OFF=-2*IDSS/gm #in Volt\n",
+      "print \"VGS(OFF) = %0.2f mV \"%(VGS_OFF*1000) "
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "VGS(OFF) = -2.00 mV \n"
+       ]
+      }
+     ],
+     "prompt_number": 6
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa 4.7 page 196"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "from __future__ import division\n",
+      "#given data :\n",
+      "VP=-4 #in Volt\n",
+      "VGS=-2 #in Volt\n",
+      "IDSS=10 #in mAmpere\n",
+      "IDSS=IDSS*10**-3 #in Ampere\n",
+      "#Formula : ID=IDSS*[1-VGS/VP]**2\n",
+      "ID=IDSS*(1-VGS/VP)**2 #in Ampere\n",
+      "print \"Drain Current = %0.2f mA \"%(ID*1000) \n",
+      "print \"The minimum value of VDS for pinch-off region is equal to VP. Thus the minimum value of VDS : VDS(min) =\",VP,\"V\" "
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Drain Current = 2.50 mA \n",
+        "The minimum value of VDS for pinch-off region is equal to VP. Thus the minimum value of VDS : VDS(min) = -4 V\n"
+       ]
+      }
+     ],
+     "prompt_number": 7
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa 4.8 page 197"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "#given data :\n",
+      "IDSS=8.7 #in mAmpere\n",
+      "IDSS=IDSS*10**-3 #in Ampere\n",
+      "VP=-3 #in Volt\n",
+      "VGS=-1 #in Volt\n",
+      "#ID\n",
+      "ID=IDSS*(1-VGS/VP)**2\n",
+      "print \"Drain current ID = %0.4f mA \"%(ID*1000) \n",
+      "#gmo\n",
+      "gmo=-2*IDSS/VP #in S\n",
+      "print \"Transconductance for VGS=0V = %0.2f mA/V or mS\"%(gmo*1000)\n",
+      "#gm\n",
+      "gm=gmo*(1-VGS/VP) #in S\n",
+      "print \"Transconductance = %0.3f mA/V or mS\"%(gm*1000) "
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Drain current ID = 3.8667 mA \n",
+        "Transconductance for VGS=0V = 5.80 mA/V or mS\n",
+        "Transconductance = 3.867 mA/V or mS\n"
+       ]
+      }
+     ],
+     "prompt_number": 8
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa 4.9 page 197"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      " \n",
+      "#given data :\n",
+      "IDSS=8.4 #in mAmpere\n",
+      "IDSS=IDSS*10**-3 #in Ampere\n",
+      "VP=-3 #in Volt\n",
+      "VGS=-1.5 #in Volt\n",
+      "#ID\n",
+      "ID=IDSS*(1-VGS/VP)**2\n",
+      "print \"Drain current ID = %0.2f mA \"%(ID*1000) \n",
+      "#gmo\n",
+      "gmo=-2*IDSS/VP #in S\n",
+      "print \"Transconductance for VGS=0V = %0.2f mA/V or mS \"%(gmo*1000) \n",
+      "gm=gmo*(1-VGS/VP) #in S\n",
+      "print \"Transconductance = %0.2f mA/V or mS \"%(gm*1000) "
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Drain current ID = 2.10 mA \n",
+        "Transconductance for VGS=0V = 5.60 mA/V or mS \n",
+        "Transconductance = 2.80 mA/V or mS \n"
+       ]
+      }
+     ],
+     "prompt_number": 9
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa 4.10 page 197"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "#given data :\n",
+      "VP=-4.5 #in Volt\n",
+      "IDSS=9 #in mAmpere\n",
+      "IDSS=IDSS*10**-3 #in Ampere\n",
+      "IDS=3 #in mAmpere\n",
+      "IDS=IDS*10**-3 #in Ampere\n",
+      "#Formula : IDS=IDSS*[1-VGS/VP]**2\n",
+      "VGS=VP*(1-sqrt(IDS/IDSS)) #in Volt\n",
+      "print \"ID=3mA at VGS = %0.3f Volt \"%(VGS) \n",
+      "gm=(-2*IDSS)*(1-VGS/VP)/VP #in mA/V or mS\n",
+      "print \"Transconductance = %0.2f mA/V or mS \"%(gm*1000) "
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "ID=3mA at VGS = -1.902 Volt \n",
+        "Transconductance = 2.31 mA/V or mS \n"
+       ]
+      }
+     ],
+     "prompt_number": 10
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa 4.11 page 197"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "from __future__ import division\n",
+      "#given data :\n",
+      "ID_on=5 #in mAmpere\n",
+      "VGS_on=8 #in Volt\n",
+      "VGS=6 #in Volt\n",
+      "VGST=4 #in Volt\n",
+      "k=ID_on/(VGS_on-VGST)**2 #in mA/V**2\n",
+      "ID=k*(VGS-VGST)**2 #in mA\n",
+      "print \"Drain current = %0.2f mA \"%ID "
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Drain current = 1.25 mA \n"
+       ]
+      }
+     ],
+     "prompt_number": 11
+    }
+   ],
+   "metadata": {}
+  }
+ ]
+}
\ No newline at end of file
diff --git a/Electrical_And_Electronics_Engineering_Materials_by_J._B._Gupta/chap5.ipynb b/Electrical_And_Electronics_Engineering_Materials_by_J._B._Gupta/chap5.ipynb
new file mode 100644
index 00000000..387f262c
--- /dev/null
+++ b/Electrical_And_Electronics_Engineering_Materials_by_J._B._Gupta/chap5.ipynb
@@ -0,0 +1,218 @@
+{
+ "metadata": {
+  "name": "",
+  "signature": "sha256:8973e988ba50241c61545087202684c50199bbf725f85368bb7440e1bdbbb193"
+ },
+ "nbformat": 3,
+ "nbformat_minor": 0,
+ "worksheets": [
+  {
+   "cells": [
+    {
+     "cell_type": "heading",
+     "level": 1,
+     "metadata": {},
+     "source": [
+      "Chapter 5 - Magnetic Properties of Materials"
+     ]
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa 5.1 page 237"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "# given data\n",
+      "Area_hysteresis_curve=9.3 #in cm**2\n",
+      "Cordinate1_1cm=1000 #in AT/m\n",
+      "Cordinate2_1cm=0.2 #in T\n",
+      "#Part (i)\n",
+      "hysteresis_loss=Area_hysteresis_curve*Cordinate1_1cm*Cordinate2_1cm #in J/m**3/cycle\n",
+      "print \"Hysteresis loss/m**3/cycle = %0.2f J/m**3/cycle \"%(hysteresis_loss) \n",
+      "#Part (ii)\n",
+      "f=50 #in Hz\n",
+      "H_LossPerCubicMeter=hysteresis_loss*f #in Watts\n",
+      "print \"Hysteresis loss Per Cubic Meter = %0.2f kW\"%(H_LossPerCubicMeter*10**-3)"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Hysteresis loss/m**3/cycle = 1860.00 J/m**3/cycle \n",
+        "Hysteresis loss Per Cubic Meter = 93.00 kW\n"
+       ]
+      }
+     ],
+     "prompt_number": 1
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa 5.2 page 237"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "# given data\n",
+      "Area_hysteresis_loop=93 #in cm**2\n",
+      "scale1_1cm=0.1 #in Wb/m**2\n",
+      "scale2_1cm=50 #in AT/m\n",
+      "\n",
+      "hysteresis_loss=Area_hysteresis_loop*scale1_1cm*scale2_1cm #in J/m**3/cycle\n",
+      "print \"Hysteresis loss/m**3/cycle = %0.2f J/m**3/cycle \"%(hysteresis_loss) \n",
+      "\n",
+      "f=65 #unit less\n",
+      "V=1500*10**-6 # in m**3\n",
+      "P_h=hysteresis_loss*f*V \n",
+      "print \"Hysteresis loss is : %0.2f\"%(P_h),\" W\" "
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Hysteresis loss/m**3/cycle = 465.00 J/m**3/cycle \n",
+        "Hysteresis loss is : 45.34  W\n"
+       ]
+      }
+     ],
+     "prompt_number": 2
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa 5.3 page 237"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "from math import floor\n",
+      "# given data\n",
+      "nita=628 # in J/m**3\n",
+      "B_max=1.3 # in Wb/m**2\n",
+      "f=25 # in Hz\n",
+      "ironMass=50 # in kg\n",
+      "densityOfIron=7.8*10**3 # in kg/m**3\n",
+      "V=ironMass/densityOfIron \n",
+      "x=12.5 # in AT/m\n",
+      "y=0.1 # in T\n",
+      "# formula Hysteresis loss/second = nita*B_max**1.6*f*V\n",
+      "H_Loss_per_second = nita*B_max**1.6*f*V  # in J/s\n",
+      "H_Loss_per_second=floor(H_Loss_per_second) \n",
+      "H_Loss_per_hour= H_Loss_per_second*60*60 # in J\n",
+      "print \"Hysteresis Loss per hour is : \",(H_Loss_per_hour),\" J\" \n",
+      "# Let Hysteresis Loss per m**3 per cycle = H1\n",
+      "H1=nita*B_max**1.6 \n",
+      "# formula  hysteresis loss/m**3/cycle = x*y*area of B-H loop\n",
+      "Area_of_B_H_loop=H1/(x*y) \n",
+      "Area_of_B_H_loop=floor(Area_of_B_H_loop) \n",
+      "print \"Area of B-H loop is : \",(Area_of_B_H_loop),\" cm**2\" "
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Hysteresis Loss per hour is :  550800.0  J\n",
+        "Area of B-H loop is :  764.0  cm**2\n"
+       ]
+      }
+     ],
+     "prompt_number": 3
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa 5.4 page 237"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "from __future__ import division\n",
+      "# given data\n",
+      "H_L_per_M_Cube_per_C=380 # in W-S\n",
+      "f=50 # unit less\n",
+      "density=7800 # in kg/m**3\n",
+      "V=1/density # in m**3\n",
+      "# formula Hysteresis loss = Hysteresis loss/m**3/cycle * f * V\n",
+      "P_h=H_L_per_M_Cube_per_C * f * V \n",
+      "print \"Hysteresis loss is : %0.2f\"%(P_h), \"W\" "
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Hysteresis loss is : 2.44 W\n"
+       ]
+      }
+     ],
+     "prompt_number": 4
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa 5.5 page 239"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "# given data\n",
+      "P_e1=1600 # in watts\n",
+      "B_max1=1.2 # in T\n",
+      "f1=50 # in Hz\n",
+      "B_max2=1.5 # in T\n",
+      "f2=60 # in Hz\n",
+      "# P_e propotional to B_max**2*f**2, so\n",
+      "P_e2=P_e1*(B_max2/B_max1)**2*(f2/f1)**2\n",
+      "print \"Eddy current loss is : \",(P_e2),\" watts\" "
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Eddy current loss is :  3600.0  watts\n"
+       ]
+      }
+     ],
+     "prompt_number": 5
+    }
+   ],
+   "metadata": {}
+  }
+ ]
+}
\ No newline at end of file
diff --git a/Electrical_And_Electronics_Engineering_Materials_by_J._B._Gupta/chap6.ipynb b/Electrical_And_Electronics_Engineering_Materials_by_J._B._Gupta/chap6.ipynb
new file mode 100644
index 00000000..1c5ade18
--- /dev/null
+++ b/Electrical_And_Electronics_Engineering_Materials_by_J._B._Gupta/chap6.ipynb
@@ -0,0 +1,177 @@
+{
+ "metadata": {
+  "name": "",
+  "signature": "sha256:4eeeffa6f59d30b4e1f2c12f47c2e935c082ccc92041f27a88a14bdc2e7590f1"
+ },
+ "nbformat": 3,
+ "nbformat_minor": 0,
+ "worksheets": [
+  {
+   "cells": [
+    {
+     "cell_type": "heading",
+     "level": 1,
+     "metadata": {},
+     "source": [
+      "Chapter 6 - Dielectric Properties of Materials"
+     ]
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa 6.1 page 291"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "from math import pi\n",
+      "# given data\n",
+      "epsilon_r=2.5 \n",
+      "epsilon_o=8.854*10**-12 \n",
+      "d=.2*10**-3 # in m\n",
+      "A=20*10**-4 # in m**2\n",
+      "omega=2*pi*10**6 # in radians/s\n",
+      "f=10**6 \n",
+      "tan_delta=4*10**-4 \n",
+      "C=epsilon_o*epsilon_r*A/d # in F\n",
+      "print \"Capicitance is : \",(C*10**12),\" miu miu F\" \n",
+      "# Formula P=V**2/R, so\n",
+      "# R=V**2/P and P= V**2*2*pi* f * C * tan delta, putting the value of P, we get\n",
+      "R=1/(2*pi*f*C*tan_delta) # in ohm\n",
+      "print \"The element of parallel R-C circuit is : %0.3f\"%(R*10**-6),\" M ohm\" "
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Capicitance is :  221.35  miu miu F\n",
+        "The element of parallel R-C circuit is : 1.798  M ohm\n"
+       ]
+      }
+     ],
+     "prompt_number": 1
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa 6.2 page 301"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "# given data\n",
+      "g=0.055 # in V-m/N\n",
+      "t=2*10**-3 # in m\n",
+      "P=1.25*10**6 # in N/m**2\n",
+      "epsilon=40.6*10**-12 # in F/m\n",
+      "V_out=g*t*P \n",
+      "print \"Output voltage is : \",(V_out),\" V\" \n",
+      "# Formula Charge Sensivity=epsilon_o*epsilon_r*g=epsilon*g\n",
+      "ChargeSensivity=epsilon*g \n",
+      "print \"Charge Sensivity is : \",(ChargeSensivity),\" C/N\" "
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Output voltage is :  137.5  V\n",
+        "Charge Sensivity is :  2.233e-12  C/N\n"
+       ]
+      }
+     ],
+     "prompt_number": 2
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa 6.3 page 301"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "# given data\n",
+      "V_out=150 # in V\n",
+      "t=2*10**-3 # in m\n",
+      "g=0.05 # in V-m/N\n",
+      "A=5*5*10**-6 # in m**2\n",
+      "F=V_out*A/(g*t) # in N\n",
+      "print \"Force applied is : \",F,\" N\""
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Force applied is :  37.5  N\n"
+       ]
+      }
+     ],
+     "prompt_number": 3
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exa 6.4 page 302"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "# given data\n",
+      "g=12*10**-3 # in V-m/N\n",
+      "t=1.25*10**-3 # in m\n",
+      "A=5*5*10**-6 # in m**2\n",
+      "F=3 # in N\n",
+      "ChargeSensitivity=150*10**-12 # in C/N\n",
+      "P=F/A \n",
+      "V_out=g*t*P # in V\n",
+      "Q=ChargeSensitivity*F \n",
+      "print \"Total charge developed is : \"+str(Q)+\" C\" \n",
+      "# Formula C=Q/V \n",
+      "C=Q/V_out \n",
+      "print \"Capacitance is : \",(C*10**12),\" micro F\" \n",
+      "\n",
+      "# Note: Answer in the Book is wrong"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Total charge developed is : 4.5e-10 C\n",
+        "Capacitance is :  250.0  micro F\n"
+       ]
+      }
+     ],
+     "prompt_number": 4
+    }
+   ],
+   "metadata": {}
+  }
+ ]
+}
\ No newline at end of file
diff --git a/Electrical_And_Electronics_Engineering_Materials_by_J._B._Gupta/screenshots/2_Charge_current_density.png b/Electrical_And_Electronics_Engineering_Materials_by_J._B._Gupta/screenshots/2_Charge_current_density.png
new file mode 100644
index 00000000..cc04d3ec
--- /dev/null
+++ b/Electrical_And_Electronics_Engineering_Materials_by_J._B._Gupta/screenshots/2_Charge_current_density.png
diff --git a/Electrical_And_Electronics_Engineering_Materials_by_J._B._Gupta/screenshots/2_temp_coeff.png b/Electrical_And_Electronics_Engineering_Materials_by_J._B._Gupta/screenshots/2_temp_coeff.png
new file mode 100644
index 00000000..96a8ec4b
--- /dev/null
+++ b/Electrical_And_Electronics_Engineering_Materials_by_J._B._Gupta/screenshots/2_temp_coeff.png
diff --git a/Electrical_And_Electronics_Engineering_Materials_by_J._B._Gupta/screenshots/Ch1DenCrystal.png b/Electrical_And_Electronics_Engineering_Materials_by_J._B._Gupta/screenshots/Ch1DenCrystal.png
new file mode 100644
index 00000000..f6acb537
--- /dev/null
+++ b/Electrical_And_Electronics_Engineering_Materials_by_J._B._Gupta/screenshots/Ch1DenCrystal.png
diff --git a/_Engineering_Thermodynamics_by__O._Singh/README.txt b/Engineering_Thermodynamics_by__O._Singh/README.txt
index 302a203f..302a203f 100755
--- a/_Engineering_Thermodynamics_by__O._Singh/README.txt
+++ b/Engineering_Thermodynamics_by__O._Singh/README.txt
diff --git a/_Engineering_Thermodynamics_by__O._Singh/chapter10.ipynb b/Engineering_Thermodynamics_by__O._Singh/chapter10.ipynb
index 2d9241c2..2d9241c2 100755
--- a/_Engineering_Thermodynamics_by__O._Singh/chapter10.ipynb
+++ b/Engineering_Thermodynamics_by__O._Singh/chapter10.ipynb
diff --git a/_Engineering_Thermodynamics_by__O._Singh/chapter10_1.ipynb b/Engineering_Thermodynamics_by__O._Singh/chapter10_1.ipynb
index 2d9241c2..2d9241c2 100755
--- a/_Engineering_Thermodynamics_by__O._Singh/chapter10_1.ipynb
+++ b/Engineering_Thermodynamics_by__O._Singh/chapter10_1.ipynb
diff --git a/_Engineering_Thermodynamics_by__O._Singh/chapter10_2.ipynb b/Engineering_Thermodynamics_by__O._Singh/chapter10_2.ipynb
index 2d9241c2..2d9241c2 100755
--- a/_Engineering_Thermodynamics_by__O._Singh/chapter10_2.ipynb
+++ b/Engineering_Thermodynamics_by__O._Singh/chapter10_2.ipynb
diff --git a/_Engineering_Thermodynamics_by__O._Singh/chapter10_3.ipynb b/Engineering_Thermodynamics_by__O._Singh/chapter10_3.ipynb
index 2d9241c2..2d9241c2 100755
--- a/_Engineering_Thermodynamics_by__O._Singh/chapter10_3.ipynb
+++ b/Engineering_Thermodynamics_by__O._Singh/chapter10_3.ipynb
diff --git a/_Engineering_Thermodynamics_by__O._Singh/chapter11.ipynb b/Engineering_Thermodynamics_by__O._Singh/chapter11.ipynb
index 31f593f0..31f593f0 100755
--- a/_Engineering_Thermodynamics_by__O._Singh/chapter11.ipynb
+++ b/Engineering_Thermodynamics_by__O._Singh/chapter11.ipynb
diff --git a/_Engineering_Thermodynamics_by__O._Singh/chapter11_1.ipynb b/Engineering_Thermodynamics_by__O._Singh/chapter11_1.ipynb
index 31f593f0..31f593f0 100755
--- a/_Engineering_Thermodynamics_by__O._Singh/chapter11_1.ipynb
+++ b/Engineering_Thermodynamics_by__O._Singh/chapter11_1.ipynb
diff --git a/_Engineering_Thermodynamics_by__O._Singh/chapter11_2.ipynb b/Engineering_Thermodynamics_by__O._Singh/chapter11_2.ipynb
index 31f593f0..31f593f0 100755
--- a/_Engineering_Thermodynamics_by__O._Singh/chapter11_2.ipynb
+++ b/Engineering_Thermodynamics_by__O._Singh/chapter11_2.ipynb
diff --git a/_Engineering_Thermodynamics_by__O._Singh/chapter11_3.ipynb b/Engineering_Thermodynamics_by__O._Singh/chapter11_3.ipynb
index 31f593f0..31f593f0 100755
--- a/_Engineering_Thermodynamics_by__O._Singh/chapter11_3.ipynb
+++ b/Engineering_Thermodynamics_by__O._Singh/chapter11_3.ipynb
diff --git a/_Engineering_Thermodynamics_by__O._Singh/chapter12.ipynb b/Engineering_Thermodynamics_by__O._Singh/chapter12.ipynb
index f89e1b1a..f89e1b1a 100755
--- a/_Engineering_Thermodynamics_by__O._Singh/chapter12.ipynb
+++ b/Engineering_Thermodynamics_by__O._Singh/chapter12.ipynb
diff --git a/_Engineering_Thermodynamics_by__O._Singh/chapter12_1.ipynb b/Engineering_Thermodynamics_by__O._Singh/chapter12_1.ipynb
index f89e1b1a..f89e1b1a 100755
--- a/_Engineering_Thermodynamics_by__O._Singh/chapter12_1.ipynb
+++ b/Engineering_Thermodynamics_by__O._Singh/chapter12_1.ipynb
diff --git a/_Engineering_Thermodynamics_by__O._Singh/chapter12_2.ipynb b/Engineering_Thermodynamics_by__O._Singh/chapter12_2.ipynb
index f89e1b1a..f89e1b1a 100755
--- a/_Engineering_Thermodynamics_by__O._Singh/chapter12_2.ipynb
+++ b/Engineering_Thermodynamics_by__O._Singh/chapter12_2.ipynb
diff --git a/_Engineering_Thermodynamics_by__O._Singh/chapter12_3.ipynb b/Engineering_Thermodynamics_by__O._Singh/chapter12_3.ipynb
index f89e1b1a..f89e1b1a 100755
--- a/_Engineering_Thermodynamics_by__O._Singh/chapter12_3.ipynb
+++ b/Engineering_Thermodynamics_by__O._Singh/chapter12_3.ipynb
diff --git a/_Engineering_Thermodynamics_by__O._Singh/chapter13.ipynb b/Engineering_Thermodynamics_by__O._Singh/chapter13.ipynb
index 836097b9..836097b9 100755
--- a/_Engineering_Thermodynamics_by__O._Singh/chapter13.ipynb
+++ b/Engineering_Thermodynamics_by__O._Singh/chapter13.ipynb
diff --git a/_Engineering_Thermodynamics_by__O._Singh/chapter13_1.ipynb b/Engineering_Thermodynamics_by__O._Singh/chapter13_1.ipynb
index 836097b9..836097b9 100755
--- a/_Engineering_Thermodynamics_by__O._Singh/chapter13_1.ipynb
+++ b/Engineering_Thermodynamics_by__O._Singh/chapter13_1.ipynb
diff --git a/_Engineering_Thermodynamics_by__O._Singh/chapter13_2.ipynb b/Engineering_Thermodynamics_by__O._Singh/chapter13_2.ipynb
index 836097b9..836097b9 100755
--- a/_Engineering_Thermodynamics_by__O._Singh/chapter13_2.ipynb
+++ b/Engineering_Thermodynamics_by__O._Singh/chapter13_2.ipynb
diff --git a/_Engineering_Thermodynamics_by__O._Singh/chapter13_3.ipynb b/Engineering_Thermodynamics_by__O._Singh/chapter13_3.ipynb
index 836097b9..836097b9 100755
--- a/_Engineering_Thermodynamics_by__O._Singh/chapter13_3.ipynb
+++ b/Engineering_Thermodynamics_by__O._Singh/chapter13_3.ipynb
diff --git a/_Engineering_Thermodynamics_by__O._Singh/chapter2.ipynb b/Engineering_Thermodynamics_by__O._Singh/chapter2.ipynb
index 6d7e9bc4..6d7e9bc4 100755
--- a/_Engineering_Thermodynamics_by__O._Singh/chapter2.ipynb
+++ b/Engineering_Thermodynamics_by__O._Singh/chapter2.ipynb
diff --git a/_Engineering_Thermodynamics_by__O._Singh/chapter2_1.ipynb b/Engineering_Thermodynamics_by__O._Singh/chapter2_1.ipynb
index 6d7e9bc4..6d7e9bc4 100755
--- a/_Engineering_Thermodynamics_by__O._Singh/chapter2_1.ipynb
+++ b/Engineering_Thermodynamics_by__O._Singh/chapter2_1.ipynb
diff --git a/_Engineering_Thermodynamics_by__O._Singh/chapter2_2.ipynb b/Engineering_Thermodynamics_by__O._Singh/chapter2_2.ipynb
index 6d7e9bc4..6d7e9bc4 100755
--- a/_Engineering_Thermodynamics_by__O._Singh/chapter2_2.ipynb
+++ b/Engineering_Thermodynamics_by__O._Singh/chapter2_2.ipynb
diff --git a/_Engineering_Thermodynamics_by__O._Singh/chapter2_3.ipynb b/Engineering_Thermodynamics_by__O._Singh/chapter2_3.ipynb
index 6d7e9bc4..6d7e9bc4 100755
--- a/_Engineering_Thermodynamics_by__O._Singh/chapter2_3.ipynb
+++ b/Engineering_Thermodynamics_by__O._Singh/chapter2_3.ipynb
diff --git a/_Engineering_Thermodynamics_by__O._Singh/chapter3.ipynb b/Engineering_Thermodynamics_by__O._Singh/chapter3.ipynb
index 22ed40c9..22ed40c9 100755
--- a/_Engineering_Thermodynamics_by__O._Singh/chapter3.ipynb
+++ b/Engineering_Thermodynamics_by__O._Singh/chapter3.ipynb
diff --git a/_Engineering_Thermodynamics_by__O._Singh/chapter3_1.ipynb b/Engineering_Thermodynamics_by__O._Singh/chapter3_1.ipynb
index 22ed40c9..22ed40c9 100755
--- a/_Engineering_Thermodynamics_by__O._Singh/chapter3_1.ipynb
+++ b/Engineering_Thermodynamics_by__O._Singh/chapter3_1.ipynb
diff --git a/_Engineering_Thermodynamics_by__O._Singh/chapter3_2.ipynb b/Engineering_Thermodynamics_by__O._Singh/chapter3_2.ipynb
index 22ed40c9..22ed40c9 100755
--- a/_Engineering_Thermodynamics_by__O._Singh/chapter3_2.ipynb
+++ b/Engineering_Thermodynamics_by__O._Singh/chapter3_2.ipynb
diff --git a/_Engineering_Thermodynamics_by__O._Singh/chapter3_3.ipynb b/Engineering_Thermodynamics_by__O._Singh/chapter3_3.ipynb
index 22ed40c9..22ed40c9 100755
--- a/_Engineering_Thermodynamics_by__O._Singh/chapter3_3.ipynb
+++ b/Engineering_Thermodynamics_by__O._Singh/chapter3_3.ipynb
diff --git a/_Engineering_Thermodynamics_by__O._Singh/chapter4.ipynb b/Engineering_Thermodynamics_by__O._Singh/chapter4.ipynb
index bb4a3703..bb4a3703 100755
--- a/_Engineering_Thermodynamics_by__O._Singh/chapter4.ipynb
+++ b/Engineering_Thermodynamics_by__O._Singh/chapter4.ipynb
diff --git a/_Engineering_Thermodynamics_by__O._Singh/chapter4_1.ipynb b/Engineering_Thermodynamics_by__O._Singh/chapter4_1.ipynb
index bb4a3703..bb4a3703 100755
--- a/_Engineering_Thermodynamics_by__O._Singh/chapter4_1.ipynb
+++ b/Engineering_Thermodynamics_by__O._Singh/chapter4_1.ipynb
diff --git a/_Engineering_Thermodynamics_by__O._Singh/chapter4_2.ipynb b/Engineering_Thermodynamics_by__O._Singh/chapter4_2.ipynb
index bb4a3703..bb4a3703 100755
--- a/_Engineering_Thermodynamics_by__O._Singh/chapter4_2.ipynb
+++ b/Engineering_Thermodynamics_by__O._Singh/chapter4_2.ipynb
diff --git a/_Engineering_Thermodynamics_by__O._Singh/chapter4_3.ipynb b/Engineering_Thermodynamics_by__O._Singh/chapter4_3.ipynb
index bb4a3703..bb4a3703 100755
--- a/_Engineering_Thermodynamics_by__O._Singh/chapter4_3.ipynb
+++ b/Engineering_Thermodynamics_by__O._Singh/chapter4_3.ipynb
diff --git a/_Engineering_Thermodynamics_by__O._Singh/chapter5.ipynb b/Engineering_Thermodynamics_by__O._Singh/chapter5.ipynb
index 2eb17c0f..2eb17c0f 100755
--- a/_Engineering_Thermodynamics_by__O._Singh/chapter5.ipynb
+++ b/Engineering_Thermodynamics_by__O._Singh/chapter5.ipynb
diff --git a/_Engineering_Thermodynamics_by__O._Singh/chapter5_1.ipynb b/Engineering_Thermodynamics_by__O._Singh/chapter5_1.ipynb
index 2eb17c0f..2eb17c0f 100755
--- a/_Engineering_Thermodynamics_by__O._Singh/chapter5_1.ipynb
+++ b/Engineering_Thermodynamics_by__O._Singh/chapter5_1.ipynb
diff --git a/_Engineering_Thermodynamics_by__O._Singh/chapter5_2.ipynb b/Engineering_Thermodynamics_by__O._Singh/chapter5_2.ipynb
index cc42cd6f..cc42cd6f 100755
--- a/_Engineering_Thermodynamics_by__O._Singh/chapter5_2.ipynb
+++ b/Engineering_Thermodynamics_by__O._Singh/chapter5_2.ipynb
diff --git a/_Engineering_Thermodynamics_by__O._Singh/chapter5_3.ipynb b/Engineering_Thermodynamics_by__O._Singh/chapter5_3.ipynb
index cc42cd6f..cc42cd6f 100755
--- a/_Engineering_Thermodynamics_by__O._Singh/chapter5_3.ipynb
+++ b/Engineering_Thermodynamics_by__O._Singh/chapter5_3.ipynb
diff --git a/_Engineering_Thermodynamics_by__O._Singh/chapter6.ipynb b/Engineering_Thermodynamics_by__O._Singh/chapter6.ipynb
index 92ef2871..92ef2871 100755
--- a/_Engineering_Thermodynamics_by__O._Singh/chapter6.ipynb
+++ b/Engineering_Thermodynamics_by__O._Singh/chapter6.ipynb
diff --git a/_Engineering_Thermodynamics_by__O._Singh/chapter6_1.ipynb b/Engineering_Thermodynamics_by__O._Singh/chapter6_1.ipynb
index 92ef2871..92ef2871 100755
--- a/_Engineering_Thermodynamics_by__O._Singh/chapter6_1.ipynb
+++ b/Engineering_Thermodynamics_by__O._Singh/chapter6_1.ipynb
diff --git a/_Engineering_Thermodynamics_by__O._Singh/chapter6_2.ipynb b/Engineering_Thermodynamics_by__O._Singh/chapter6_2.ipynb
index 92ef2871..92ef2871 100755
--- a/_Engineering_Thermodynamics_by__O._Singh/chapter6_2.ipynb
+++ b/Engineering_Thermodynamics_by__O._Singh/chapter6_2.ipynb
diff --git a/_Engineering_Thermodynamics_by__O._Singh/chapter6_3.ipynb b/Engineering_Thermodynamics_by__O._Singh/chapter6_3.ipynb
index 92ef2871..92ef2871 100755
--- a/_Engineering_Thermodynamics_by__O._Singh/chapter6_3.ipynb
+++ b/Engineering_Thermodynamics_by__O._Singh/chapter6_3.ipynb
diff --git a/_Engineering_Thermodynamics_by__O._Singh/chapter7-Copy1.ipynb b/Engineering_Thermodynamics_by__O._Singh/chapter7-Copy1.ipynb
index c10f28b4..c10f28b4 100755
--- a/_Engineering_Thermodynamics_by__O._Singh/chapter7-Copy1.ipynb
+++ b/Engineering_Thermodynamics_by__O._Singh/chapter7-Copy1.ipynb
diff --git a/_Engineering_Thermodynamics_by__O._Singh/chapter7.ipynb b/Engineering_Thermodynamics_by__O._Singh/chapter7.ipynb
index ef30a163..ef30a163 100755
--- a/_Engineering_Thermodynamics_by__O._Singh/chapter7.ipynb
+++ b/Engineering_Thermodynamics_by__O._Singh/chapter7.ipynb
diff --git a/_Engineering_Thermodynamics_by__O._Singh/chapter7_1.ipynb b/Engineering_Thermodynamics_by__O._Singh/chapter7_1.ipynb
index ef30a163..ef30a163 100755
--- a/_Engineering_Thermodynamics_by__O._Singh/chapter7_1.ipynb
+++ b/Engineering_Thermodynamics_by__O._Singh/chapter7_1.ipynb
diff --git a/_Engineering_Thermodynamics_by__O._Singh/chapter7_2.ipynb b/Engineering_Thermodynamics_by__O._Singh/chapter7_2.ipynb
index 8171c9b6..8171c9b6 100755
--- a/_Engineering_Thermodynamics_by__O._Singh/chapter7_2.ipynb
+++ b/Engineering_Thermodynamics_by__O._Singh/chapter7_2.ipynb
diff --git a/_Engineering_Thermodynamics_by__O._Singh/chapter8.ipynb b/Engineering_Thermodynamics_by__O._Singh/chapter8.ipynb
index 5088b9af..5088b9af 100755
--- a/_Engineering_Thermodynamics_by__O._Singh/chapter8.ipynb
+++ b/Engineering_Thermodynamics_by__O._Singh/chapter8.ipynb
diff --git a/_Engineering_Thermodynamics_by__O._Singh/chapter8_1.ipynb b/Engineering_Thermodynamics_by__O._Singh/chapter8_1.ipynb
index 5088b9af..5088b9af 100755
--- a/_Engineering_Thermodynamics_by__O._Singh/chapter8_1.ipynb
+++ b/Engineering_Thermodynamics_by__O._Singh/chapter8_1.ipynb
diff --git a/_Engineering_Thermodynamics_by__O._Singh/chapter8_2.ipynb b/Engineering_Thermodynamics_by__O._Singh/chapter8_2.ipynb
index 5088b9af..5088b9af 100755
--- a/_Engineering_Thermodynamics_by__O._Singh/chapter8_2.ipynb
+++ b/Engineering_Thermodynamics_by__O._Singh/chapter8_2.ipynb
diff --git a/_Engineering_Thermodynamics_by__O._Singh/chapter8_3.ipynb b/Engineering_Thermodynamics_by__O._Singh/chapter8_3.ipynb
index 5088b9af..5088b9af 100755
--- a/_Engineering_Thermodynamics_by__O._Singh/chapter8_3.ipynb
+++ b/Engineering_Thermodynamics_by__O._Singh/chapter8_3.ipynb
diff --git a/_Engineering_Thermodynamics_by__O._Singh/chapter9.ipynb b/Engineering_Thermodynamics_by__O._Singh/chapter9.ipynb
index 606321b3..606321b3 100755
--- a/_Engineering_Thermodynamics_by__O._Singh/chapter9.ipynb
+++ b/Engineering_Thermodynamics_by__O._Singh/chapter9.ipynb
diff --git a/_Engineering_Thermodynamics_by__O._Singh/chapter9_1.ipynb b/Engineering_Thermodynamics_by__O._Singh/chapter9_1.ipynb
index 606321b3..606321b3 100755
--- a/_Engineering_Thermodynamics_by__O._Singh/chapter9_1.ipynb
+++ b/Engineering_Thermodynamics_by__O._Singh/chapter9_1.ipynb
diff --git a/_Engineering_Thermodynamics_by__O._Singh/chapter9_2.ipynb b/Engineering_Thermodynamics_by__O._Singh/chapter9_2.ipynb
index 606321b3..606321b3 100755
--- a/_Engineering_Thermodynamics_by__O._Singh/chapter9_2.ipynb
+++ b/Engineering_Thermodynamics_by__O._Singh/chapter9_2.ipynb
diff --git a/_Engineering_Thermodynamics_by__O._Singh/chapter9_3.ipynb b/Engineering_Thermodynamics_by__O._Singh/chapter9_3.ipynb
index 606321b3..606321b3 100755
--- a/_Engineering_Thermodynamics_by__O._Singh/chapter9_3.ipynb
+++ b/Engineering_Thermodynamics_by__O._Singh/chapter9_3.ipynb
diff --git a/_Engineering_Thermodynamics_by__O._Singh/chapter_1.ipynb b/Engineering_Thermodynamics_by__O._Singh/chapter_1.ipynb
index 9474d100..9474d100 100755
--- a/_Engineering_Thermodynamics_by__O._Singh/chapter_1.ipynb
+++ b/Engineering_Thermodynamics_by__O._Singh/chapter_1.ipynb
diff --git a/_Engineering_Thermodynamics_by__O._Singh/chapter_1_1.ipynb b/Engineering_Thermodynamics_by__O._Singh/chapter_1_1.ipynb
index 9474d100..9474d100 100755
--- a/_Engineering_Thermodynamics_by__O._Singh/chapter_1_1.ipynb
+++ b/Engineering_Thermodynamics_by__O._Singh/chapter_1_1.ipynb
diff --git a/_Engineering_Thermodynamics_by__O._Singh/chapter_1_2.ipynb b/Engineering_Thermodynamics_by__O._Singh/chapter_1_2.ipynb
index 9474d100..9474d100 100755
--- a/_Engineering_Thermodynamics_by__O._Singh/chapter_1_2.ipynb
+++ b/Engineering_Thermodynamics_by__O._Singh/chapter_1_2.ipynb
diff --git a/_Engineering_Thermodynamics_by__O._Singh/chapter_1_3.ipynb b/Engineering_Thermodynamics_by__O._Singh/chapter_1_3.ipynb
index 9474d100..9474d100 100755
--- a/_Engineering_Thermodynamics_by__O._Singh/chapter_1_3.ipynb
+++ b/Engineering_Thermodynamics_by__O._Singh/chapter_1_3.ipynb
diff --git a/_Engineering_Thermodynamics/screenshots/Screenshot_(49).png b/Engineering_Thermodynamics_by__O._Singh/screenshots/Screenshot_(49).png
index 69b43e33..69b43e33 100755
--- a/_Engineering_Thermodynamics/screenshots/Screenshot_(49).png
+++ b/Engineering_Thermodynamics_by__O._Singh/screenshots/Screenshot_(49).png
diff --git a/_Engineering_Thermodynamics_by__O._Singh/screenshots/Screenshot_(49)_1.png b/Engineering_Thermodynamics_by__O._Singh/screenshots/Screenshot_(49)_1.png
index 69b43e33..69b43e33 100755
--- a/_Engineering_Thermodynamics_by__O._Singh/screenshots/Screenshot_(49)_1.png
+++ b/Engineering_Thermodynamics_by__O._Singh/screenshots/Screenshot_(49)_1.png
diff --git a/_Engineering_Thermodynamics_by__O._Singh/screenshots/Screenshot_(49)_2.png b/Engineering_Thermodynamics_by__O._Singh/screenshots/Screenshot_(49)_2.png
index 69b43e33..69b43e33 100755
--- a/_Engineering_Thermodynamics_by__O._Singh/screenshots/Screenshot_(49)_2.png
+++ b/Engineering_Thermodynamics_by__O._Singh/screenshots/Screenshot_(49)_2.png
diff --git a/_Engineering_Thermodynamics/screenshots/Screenshot_(50).png b/Engineering_Thermodynamics_by__O._Singh/screenshots/Screenshot_(50).png
index b8c7aad6..b8c7aad6 100755
--- a/_Engineering_Thermodynamics/screenshots/Screenshot_(50).png
+++ b/Engineering_Thermodynamics_by__O._Singh/screenshots/Screenshot_(50).png
diff --git a/_Engineering_Thermodynamics_by__O._Singh/screenshots/Screenshot_(50)_1.png b/Engineering_Thermodynamics_by__O._Singh/screenshots/Screenshot_(50)_1.png
index b8c7aad6..b8c7aad6 100755
--- a/_Engineering_Thermodynamics_by__O._Singh/screenshots/Screenshot_(50)_1.png
+++ b/Engineering_Thermodynamics_by__O._Singh/screenshots/Screenshot_(50)_1.png
diff --git a/_Engineering_Thermodynamics_by__O._Singh/screenshots/Screenshot_(50)_2.png b/Engineering_Thermodynamics_by__O._Singh/screenshots/Screenshot_(50)_2.png
index b8c7aad6..b8c7aad6 100755
--- a/_Engineering_Thermodynamics_by__O._Singh/screenshots/Screenshot_(50)_2.png
+++ b/Engineering_Thermodynamics_by__O._Singh/screenshots/Screenshot_(50)_2.png
diff --git a/_Engineering_Thermodynamics/screenshots/Screenshot_(51).png b/Engineering_Thermodynamics_by__O._Singh/screenshots/Screenshot_(51).png
index f3bb8ad5..f3bb8ad5 100755
--- a/_Engineering_Thermodynamics/screenshots/Screenshot_(51).png
+++ b/Engineering_Thermodynamics_by__O._Singh/screenshots/Screenshot_(51).png
diff --git a/_Engineering_Thermodynamics_by__O._Singh/screenshots/Screenshot_(51)_1.png b/Engineering_Thermodynamics_by__O._Singh/screenshots/Screenshot_(51)_1.png
index f3bb8ad5..f3bb8ad5 100755
--- a/_Engineering_Thermodynamics_by__O._Singh/screenshots/Screenshot_(51)_1.png
+++ b/Engineering_Thermodynamics_by__O._Singh/screenshots/Screenshot_(51)_1.png
diff --git a/_Engineering_Thermodynamics_by__O._Singh/screenshots/Screenshot_(51)_2.png b/Engineering_Thermodynamics_by__O._Singh/screenshots/Screenshot_(51)_2.png
index f3bb8ad5..f3bb8ad5 100755
--- a/_Engineering_Thermodynamics_by__O._Singh/screenshots/Screenshot_(51)_2.png
+++ b/Engineering_Thermodynamics_by__O._Singh/screenshots/Screenshot_(51)_2.png
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_10_Solid_Solutions_and_Phase_Equilibrium.ipynb b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_10_Solid_Solutions_and_Phase_Equilibrium.ipynb
index e19d65e0..e19d65e0 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_10_Solid_Solutions_and_Phase_Equilibrium.ipynb
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_10_Solid_Solutions_and_Phase_Equilibrium.ipynb
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_10_Solid_Solutions_and_Phase_Equilibrium_1.ipynb b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_10_Solid_Solutions_and_Phase_Equilibrium_1.ipynb
index e19d65e0..e19d65e0 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_10_Solid_Solutions_and_Phase_Equilibrium_1.ipynb
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_10_Solid_Solutions_and_Phase_Equilibrium_1.ipynb
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_10_Solid_Solutions_and_Phase_Equilibrium_2.ipynb b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_10_Solid_Solutions_and_Phase_Equilibrium_2.ipynb
index 3289e7a6..3289e7a6 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_10_Solid_Solutions_and_Phase_Equilibrium_2.ipynb
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_10_Solid_Solutions_and_Phase_Equilibrium_2.ipynb
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_10_Solid_Solutions_and_Phase_Equilibrium_3.ipynb b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_10_Solid_Solutions_and_Phase_Equilibrium_3.ipynb
index 3289e7a6..3289e7a6 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_10_Solid_Solutions_and_Phase_Equilibrium_3.ipynb
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_10_Solid_Solutions_and_Phase_Equilibrium_3.ipynb
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_11_Dispertion_Strengthening_and_Eutectic_Phase_Diagrams.ipynb b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_11_Dispertion_Strengthening_and_Eutectic_Phase_Diagrams.ipynb
index f63c3411..f63c3411 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_11_Dispertion_Strengthening_and_Eutectic_Phase_Diagrams.ipynb
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_11_Dispertion_Strengthening_and_Eutectic_Phase_Diagrams.ipynb
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_11_Dispertion_Strengthening_and_Eutectic_Phase_Diagrams_1.ipynb b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_11_Dispertion_Strengthening_and_Eutectic_Phase_Diagrams_1.ipynb
index f63c3411..f63c3411 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_11_Dispertion_Strengthening_and_Eutectic_Phase_Diagrams_1.ipynb
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_11_Dispertion_Strengthening_and_Eutectic_Phase_Diagrams_1.ipynb
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_11_Dispertion_Strengthening_and_Eutectic_Phase_Diagrams_2.ipynb b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_11_Dispertion_Strengthening_and_Eutectic_Phase_Diagrams_2.ipynb
index 84eb7ae5..84eb7ae5 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_11_Dispertion_Strengthening_and_Eutectic_Phase_Diagrams_2.ipynb
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_11_Dispertion_Strengthening_and_Eutectic_Phase_Diagrams_2.ipynb
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_11_Dispertion_Strengthening_and_Eutectic_Phase_Diagrams_3.ipynb b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_11_Dispertion_Strengthening_and_Eutectic_Phase_Diagrams_3.ipynb
index 84eb7ae5..84eb7ae5 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_11_Dispertion_Strengthening_and_Eutectic_Phase_Diagrams_3.ipynb
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_11_Dispertion_Strengthening_and_Eutectic_Phase_Diagrams_3.ipynb
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_12_Dispersion_Strengthening__by_Phase_Transmission_and_Heat_Treatment.ipynb b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_12_Dispersion_Strengthening__by_Phase_Transmission_and_Heat_Treatment.ipynb
index 228a9818..228a9818 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_12_Dispersion_Strengthening__by_Phase_Transmission_and_Heat_Treatment.ipynb
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_12_Dispersion_Strengthening__by_Phase_Transmission_and_Heat_Treatment.ipynb
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_12_Dispersion_Strengthening__by_Phase_Transmission_and_Heat_Treatment_1.ipynb b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_12_Dispersion_Strengthening__by_Phase_Transmission_and_Heat_Treatment_1.ipynb
index 228a9818..228a9818 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_12_Dispersion_Strengthening__by_Phase_Transmission_and_Heat_Treatment_1.ipynb
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_12_Dispersion_Strengthening__by_Phase_Transmission_and_Heat_Treatment_1.ipynb
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_12_Dispersion_Strengthening__by_Phase_Transmission_and_Heat_Treatment_2.ipynb b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_12_Dispersion_Strengthening__by_Phase_Transmission_and_Heat_Treatment_2.ipynb
index a7fd04dc..a7fd04dc 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_12_Dispersion_Strengthening__by_Phase_Transmission_and_Heat_Treatment_2.ipynb
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_12_Dispersion_Strengthening__by_Phase_Transmission_and_Heat_Treatment_2.ipynb
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_12_Dispersion_Strengthening__by_Phase_Transmission_and_Heat_Treatment_3.ipynb b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_12_Dispersion_Strengthening__by_Phase_Transmission_and_Heat_Treatment_3.ipynb
index a7fd04dc..a7fd04dc 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_12_Dispersion_Strengthening__by_Phase_Transmission_and_Heat_Treatment_3.ipynb
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_12_Dispersion_Strengthening__by_Phase_Transmission_and_Heat_Treatment_3.ipynb
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_13_Heat_treatment_of_Steels_and_Cast_Iron.ipynb b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_13_Heat_treatment_of_Steels_and_Cast_Iron.ipynb
index ca546fd3..ca546fd3 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_13_Heat_treatment_of_Steels_and_Cast_Iron.ipynb
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_13_Heat_treatment_of_Steels_and_Cast_Iron.ipynb
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_13_Heat_treatment_of_Steels_and_Cast_Iron_1.ipynb b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_13_Heat_treatment_of_Steels_and_Cast_Iron_1.ipynb
index ca546fd3..ca546fd3 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_13_Heat_treatment_of_Steels_and_Cast_Iron_1.ipynb
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_13_Heat_treatment_of_Steels_and_Cast_Iron_1.ipynb
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_13_Heat_treatment_of_Steels_and_Cast_Iron_2.ipynb b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_13_Heat_treatment_of_Steels_and_Cast_Iron_2.ipynb
index d8b06316..d8b06316 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_13_Heat_treatment_of_Steels_and_Cast_Iron_2.ipynb
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_13_Heat_treatment_of_Steels_and_Cast_Iron_2.ipynb
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_13_Heat_treatment_of_Steels_and_Cast_Iron_3.ipynb b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_13_Heat_treatment_of_Steels_and_Cast_Iron_3.ipynb
index d8b06316..d8b06316 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_13_Heat_treatment_of_Steels_and_Cast_Iron_3.ipynb
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_13_Heat_treatment_of_Steels_and_Cast_Iron_3.ipynb
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_14_Nonferrous_Alloy.ipynb b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_14_Nonferrous_Alloy.ipynb
index b25dd603..b25dd603 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_14_Nonferrous_Alloy.ipynb
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_14_Nonferrous_Alloy.ipynb
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_14_Nonferrous_Alloy_1.ipynb b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_14_Nonferrous_Alloy_1.ipynb
index b25dd603..b25dd603 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_14_Nonferrous_Alloy_1.ipynb
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_14_Nonferrous_Alloy_1.ipynb
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_14_Nonferrous_Alloy_2.ipynb b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_14_Nonferrous_Alloy_2.ipynb
index 2fda7c51..2fda7c51 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_14_Nonferrous_Alloy_2.ipynb
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_14_Nonferrous_Alloy_2.ipynb
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_14_Nonferrous_Alloy_3.ipynb b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_14_Nonferrous_Alloy_3.ipynb
index 2fda7c51..2fda7c51 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_14_Nonferrous_Alloy_3.ipynb
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_14_Nonferrous_Alloy_3.ipynb
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_15_Ceramic_Materials.ipynb b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_15_Ceramic_Materials.ipynb
index 7f24b9ba..7f24b9ba 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_15_Ceramic_Materials.ipynb
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_15_Ceramic_Materials.ipynb
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_15_Ceramic_Materials_1.ipynb b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_15_Ceramic_Materials_1.ipynb
index 7f24b9ba..7f24b9ba 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_15_Ceramic_Materials_1.ipynb
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_15_Ceramic_Materials_1.ipynb
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_15_Ceramic_Materials_2.ipynb b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_15_Ceramic_Materials_2.ipynb
index 9fe28829..9fe28829 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_15_Ceramic_Materials_2.ipynb
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_15_Ceramic_Materials_2.ipynb
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_15_Ceramic_Materials_3.ipynb b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_15_Ceramic_Materials_3.ipynb
index 9fe28829..9fe28829 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_15_Ceramic_Materials_3.ipynb
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_15_Ceramic_Materials_3.ipynb
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_16_Polymers.ipynb b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_16_Polymers.ipynb
index 699eac73..699eac73 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_16_Polymers.ipynb
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_16_Polymers.ipynb
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_16_Polymers_1.ipynb b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_16_Polymers_1.ipynb
index 699eac73..699eac73 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_16_Polymers_1.ipynb
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_16_Polymers_1.ipynb
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_16_Polymers_2.ipynb b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_16_Polymers_2.ipynb
index be45c561..be45c561 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_16_Polymers_2.ipynb
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_16_Polymers_2.ipynb
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_16_Polymers_3.ipynb b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_16_Polymers_3.ipynb
index be45c561..be45c561 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_16_Polymers_3.ipynb
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_16_Polymers_3.ipynb
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_17_Composites_Teamwork_and_Synergy_in_Materials.ipynb b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_17_Composites_Teamwork_and_Synergy_in_Materials.ipynb
index ced00220..ced00220 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_17_Composites_Teamwork_and_Synergy_in_Materials.ipynb
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_17_Composites_Teamwork_and_Synergy_in_Materials.ipynb
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_17_Composites_Teamwork_and_Synergy_in_Materials_1.ipynb b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_17_Composites_Teamwork_and_Synergy_in_Materials_1.ipynb
index ced00220..ced00220 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_17_Composites_Teamwork_and_Synergy_in_Materials_1.ipynb
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_17_Composites_Teamwork_and_Synergy_in_Materials_1.ipynb
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_17_Composites_Teamwork_and_Synergy_in_Materials_2.ipynb b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_17_Composites_Teamwork_and_Synergy_in_Materials_2.ipynb
index 90486f14..90486f14 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_17_Composites_Teamwork_and_Synergy_in_Materials_2.ipynb
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_17_Composites_Teamwork_and_Synergy_in_Materials_2.ipynb
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_17_Composites_Teamwork_and_Synergy_in_Materials_3.ipynb b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_17_Composites_Teamwork_and_Synergy_in_Materials_3.ipynb
index 90486f14..90486f14 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_17_Composites_Teamwork_and_Synergy_in_Materials_3.ipynb
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_17_Composites_Teamwork_and_Synergy_in_Materials_3.ipynb
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_2_Atomic_Structure_.ipynb b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_2_Atomic_Structure_.ipynb
index 2aa41b7b..2aa41b7b 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_2_Atomic_Structure_.ipynb
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_2_Atomic_Structure_.ipynb
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_2_Atomic_Structure__1.ipynb b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_2_Atomic_Structure__1.ipynb
index 2aa41b7b..2aa41b7b 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_2_Atomic_Structure__1.ipynb
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_2_Atomic_Structure__1.ipynb
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_2_Atomic_Structure__2.ipynb b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_2_Atomic_Structure__2.ipynb
index 0b6ced02..0b6ced02 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_2_Atomic_Structure__2.ipynb
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_2_Atomic_Structure__2.ipynb
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_2_Atomic_Structure__3.ipynb b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_2_Atomic_Structure__3.ipynb
index 0b6ced02..0b6ced02 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_2_Atomic_Structure__3.ipynb
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_2_Atomic_Structure__3.ipynb
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_3_Atomic_and_Ionic_Arrangements.ipynb b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_3_Atomic_and_Ionic_Arrangements.ipynb
index 274d34f1..274d34f1 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_3_Atomic_and_Ionic_Arrangements.ipynb
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_3_Atomic_and_Ionic_Arrangements.ipynb
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_3_Atomic_and_Ionic_Arrangements_1.ipynb b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_3_Atomic_and_Ionic_Arrangements_1.ipynb
index 274d34f1..274d34f1 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_3_Atomic_and_Ionic_Arrangements_1.ipynb
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_3_Atomic_and_Ionic_Arrangements_1.ipynb
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_3_Atomic_and_Ionic_Arrangements_2.ipynb b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_3_Atomic_and_Ionic_Arrangements_2.ipynb
index abd0fb55..abd0fb55 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_3_Atomic_and_Ionic_Arrangements_2.ipynb
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_3_Atomic_and_Ionic_Arrangements_2.ipynb
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_3_Atomic_and_Ionic_Arrangements_3.ipynb b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_3_Atomic_and_Ionic_Arrangements_3.ipynb
index efb78d3d..efb78d3d 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_3_Atomic_and_Ionic_Arrangements_3.ipynb
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_3_Atomic_and_Ionic_Arrangements_3.ipynb
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_4_Imperfections_in_Atomic_and_Ionic_Arrangements.ipynb b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_4_Imperfections_in_Atomic_and_Ionic_Arrangements.ipynb
index 14b3eaf6..14b3eaf6 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_4_Imperfections_in_Atomic_and_Ionic_Arrangements.ipynb
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_4_Imperfections_in_Atomic_and_Ionic_Arrangements.ipynb
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_4_Imperfections_in_Atomic_and_Ionic_Arrangements_1.ipynb b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_4_Imperfections_in_Atomic_and_Ionic_Arrangements_1.ipynb
index 14b3eaf6..14b3eaf6 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_4_Imperfections_in_Atomic_and_Ionic_Arrangements_1.ipynb
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_4_Imperfections_in_Atomic_and_Ionic_Arrangements_1.ipynb
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_4_Imperfections_in_Atomic_and_Ionic_Arrangements_2.ipynb b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_4_Imperfections_in_Atomic_and_Ionic_Arrangements_2.ipynb
index def0cffe..def0cffe 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_4_Imperfections_in_Atomic_and_Ionic_Arrangements_2.ipynb
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_4_Imperfections_in_Atomic_and_Ionic_Arrangements_2.ipynb
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_4_Imperfections_in_Atomic_and_Ionic_Arrangements_3.ipynb b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_4_Imperfections_in_Atomic_and_Ionic_Arrangements_3.ipynb
index def0cffe..def0cffe 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_4_Imperfections_in_Atomic_and_Ionic_Arrangements_3.ipynb
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_4_Imperfections_in_Atomic_and_Ionic_Arrangements_3.ipynb
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_5_Atoms_and_Ion_Moments_in_Materials.ipynb b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_5_Atoms_and_Ion_Moments_in_Materials.ipynb
index a50ef08f..a50ef08f 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_5_Atoms_and_Ion_Moments_in_Materials.ipynb
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_5_Atoms_and_Ion_Moments_in_Materials.ipynb
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_5_Atoms_and_Ion_Moments_in_Materials_1.ipynb b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_5_Atoms_and_Ion_Moments_in_Materials_1.ipynb
index a50ef08f..a50ef08f 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_5_Atoms_and_Ion_Moments_in_Materials_1.ipynb
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_5_Atoms_and_Ion_Moments_in_Materials_1.ipynb
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_5_Atoms_and_Ion_Moments_in_Materials_2.ipynb b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_5_Atoms_and_Ion_Moments_in_Materials_2.ipynb
index e4f25582..e4f25582 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_5_Atoms_and_Ion_Moments_in_Materials_2.ipynb
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_5_Atoms_and_Ion_Moments_in_Materials_2.ipynb
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_5_Atoms_and_Ion_Moments_in_Materials_3.ipynb b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_5_Atoms_and_Ion_Moments_in_Materials_3.ipynb
index e4f25582..e4f25582 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_5_Atoms_and_Ion_Moments_in_Materials_3.ipynb
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_5_Atoms_and_Ion_Moments_in_Materials_3.ipynb
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_6_Mechanical_Properties_part_one.ipynb b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_6_Mechanical_Properties_part_one.ipynb
index 99ecc7a7..99ecc7a7 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_6_Mechanical_Properties_part_one.ipynb
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_6_Mechanical_Properties_part_one.ipynb
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_6_Mechanical_Properties_part_one_1.ipynb b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_6_Mechanical_Properties_part_one_1.ipynb
index 99ecc7a7..99ecc7a7 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_6_Mechanical_Properties_part_one_1.ipynb
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_6_Mechanical_Properties_part_one_1.ipynb
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_6_Mechanical_Properties_part_one_2.ipynb b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_6_Mechanical_Properties_part_one_2.ipynb
index a9f18f16..a9f18f16 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_6_Mechanical_Properties_part_one_2.ipynb
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_6_Mechanical_Properties_part_one_2.ipynb
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_6_Mechanical_Properties_part_one_3.ipynb b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_6_Mechanical_Properties_part_one_3.ipynb
index a9f18f16..a9f18f16 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_6_Mechanical_Properties_part_one_3.ipynb
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_6_Mechanical_Properties_part_one_3.ipynb
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_7_Mechanical_Properties_part_two.ipynb b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_7_Mechanical_Properties_part_two.ipynb
index d709254e..d709254e 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_7_Mechanical_Properties_part_two.ipynb
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_7_Mechanical_Properties_part_two.ipynb
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_7_Mechanical_Properties_part_two_1.ipynb b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_7_Mechanical_Properties_part_two_1.ipynb
index d709254e..d709254e 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_7_Mechanical_Properties_part_two_1.ipynb
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_7_Mechanical_Properties_part_two_1.ipynb
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_7_Mechanical_Properties_part_two_2.ipynb b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_7_Mechanical_Properties_part_two_2.ipynb
index 481aa53d..481aa53d 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_7_Mechanical_Properties_part_two_2.ipynb
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_7_Mechanical_Properties_part_two_2.ipynb
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_7_Mechanical_Properties_part_two_3.ipynb b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_7_Mechanical_Properties_part_two_3.ipynb
index 481aa53d..481aa53d 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_7_Mechanical_Properties_part_two_3.ipynb
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_7_Mechanical_Properties_part_two_3.ipynb
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_8_Strain_Hardening_and_Annealing_.ipynb b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_8_Strain_Hardening_and_Annealing_.ipynb
index 746aa314..746aa314 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_8_Strain_Hardening_and_Annealing_.ipynb
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_8_Strain_Hardening_and_Annealing_.ipynb
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_8_Strain_Hardening_and_Annealing__1.ipynb b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_8_Strain_Hardening_and_Annealing__1.ipynb
index 746aa314..746aa314 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_8_Strain_Hardening_and_Annealing__1.ipynb
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_8_Strain_Hardening_and_Annealing__1.ipynb
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_8_Strain_Hardening_and_Annealing__2.ipynb b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_8_Strain_Hardening_and_Annealing__2.ipynb
index e78c64e9..e78c64e9 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_8_Strain_Hardening_and_Annealing__2.ipynb
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_8_Strain_Hardening_and_Annealing__2.ipynb
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_8_Strain_Hardening_and_Annealing__3.ipynb b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_8_Strain_Hardening_and_Annealing__3.ipynb
index e78c64e9..e78c64e9 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_8_Strain_Hardening_and_Annealing__3.ipynb
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_8_Strain_Hardening_and_Annealing__3.ipynb
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_9_Principles_of_Solidification.ipynb b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_9_Principles_of_Solidification.ipynb
index f4d5de3a..f4d5de3a 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_9_Principles_of_Solidification.ipynb
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_9_Principles_of_Solidification.ipynb
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_9_Principles_of_Solidification_1.ipynb b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_9_Principles_of_Solidification_1.ipynb
index c5febd67..c5febd67 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_9_Principles_of_Solidification_1.ipynb
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_9_Principles_of_Solidification_1.ipynb
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_9_Principles_of_Solidification_2.ipynb b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_9_Principles_of_Solidification_2.ipynb
index 54ba9da7..54ba9da7 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_9_Principles_of_Solidification_2.ipynb
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_9_Principles_of_Solidification_2.ipynb
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_9_Principles_of_Solidification_3.ipynb b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_9_Principles_of_Solidification_3.ipynb
index 54ba9da7..54ba9da7 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_9_Principles_of_Solidification_3.ipynb
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/Chapter_9_Principles_of_Solidification_3.ipynb
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/README.txt b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/README.txt
index 28f927ec..28f927ec 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/README.txt
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/README.txt
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/screenshots/cha_10.png b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/screenshots/cha_10.png
index 6a791a7f..6a791a7f 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/screenshots/cha_10.png
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/screenshots/cha_10.png
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/screenshots/cha_10_1.png b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/screenshots/cha_10_1.png
index 6a791a7f..6a791a7f 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/screenshots/cha_10_1.png
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/screenshots/cha_10_1.png
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/screenshots/cha_10_2.png b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/screenshots/cha_10_2.png
index 6a791a7f..6a791a7f 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/screenshots/cha_10_2.png
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/screenshots/cha_10_2.png
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/screenshots/cha_10_3.png b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/screenshots/cha_10_3.png
index 6a791a7f..6a791a7f 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/screenshots/cha_10_3.png
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/screenshots/cha_10_3.png
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/screenshots/cha_11.png b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/screenshots/cha_11.png
index dd23786a..dd23786a 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/screenshots/cha_11.png
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/screenshots/cha_11.png
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/screenshots/cha_11_1.png b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/screenshots/cha_11_1.png
index dd23786a..dd23786a 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/screenshots/cha_11_1.png
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/screenshots/cha_11_1.png
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/screenshots/cha_11_2.png b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/screenshots/cha_11_2.png
index dd23786a..dd23786a 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/screenshots/cha_11_2.png
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/screenshots/cha_11_2.png
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/screenshots/cha_11_3.png b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/screenshots/cha_11_3.png
index dd23786a..dd23786a 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/screenshots/cha_11_3.png
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/screenshots/cha_11_3.png
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/screenshots/cha_4.png b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/screenshots/cha_4.png
index 6ee0ef63..6ee0ef63 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/screenshots/cha_4.png
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/screenshots/cha_4.png
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/screenshots/cha_4_1.png b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/screenshots/cha_4_1.png
index 6ee0ef63..6ee0ef63 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/screenshots/cha_4_1.png
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/screenshots/cha_4_1.png
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/screenshots/cha_4_2.png b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/screenshots/cha_4_2.png
index 6ee0ef63..6ee0ef63 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/screenshots/cha_4_2.png
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/screenshots/cha_4_2.png
diff --git a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/screenshots/cha_4_3.png b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/screenshots/cha_4_3.png
index 6ee0ef63..6ee0ef63 100755
--- a/_Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/screenshots/cha_4_3.png
+++ b/Essentials_of_Materials_Science_and_Engineering_by__D._R._Askeland_and_P._P._Phule/screenshots/cha_4_3.png
diff --git a/_Introduction_to_Nuclear_Engineering_by_J._R._Lamarsh_and_A._J._Baratta/Chapter10.ipynb b/Introduction_to_Nuclear_Engineering_by_J._R._Lamarsh_and_A._J._Baratta/Chapter10.ipynb
index f34f7c1f..f34f7c1f 100644
--- a/_Introduction_to_Nuclear_Engineering_by_J._R._Lamarsh_and_A._J._Baratta/Chapter10.ipynb
+++ b/Introduction_to_Nuclear_Engineering_by_J._R._Lamarsh_and_A._J._Baratta/Chapter10.ipynb
diff --git a/_Introduction_to_Nuclear_Engineering_by_J._R._Lamarsh_and_A._J._Baratta/Chapter11.ipynb b/Introduction_to_Nuclear_Engineering_by_J._R._Lamarsh_and_A._J._Baratta/Chapter11.ipynb
index 3707f403..3707f403 100644
--- a/_Introduction_to_Nuclear_Engineering_by_J._R._Lamarsh_and_A._J._Baratta/Chapter11.ipynb
+++ b/Introduction_to_Nuclear_Engineering_by_J._R._Lamarsh_and_A._J._Baratta/Chapter11.ipynb
diff --git a/_Introduction_to_Nuclear_Engineering_by_J._R._Lamarsh_and_A._J._Baratta/Chapter2.ipynb b/Introduction_to_Nuclear_Engineering_by_J._R._Lamarsh_and_A._J._Baratta/Chapter2.ipynb
index 421dbd88..421dbd88 100644
--- a/_Introduction_to_Nuclear_Engineering_by_J._R._Lamarsh_and_A._J._Baratta/Chapter2.ipynb
+++ b/Introduction_to_Nuclear_Engineering_by_J._R._Lamarsh_and_A._J._Baratta/Chapter2.ipynb
diff --git a/_Introduction_to_Nuclear_Engineering_by_J._R._Lamarsh_and_A._J._Baratta/Chapter3.ipynb b/Introduction_to_Nuclear_Engineering_by_J._R._Lamarsh_and_A._J._Baratta/Chapter3.ipynb
index ee6e14f0..ee6e14f0 100644
--- a/_Introduction_to_Nuclear_Engineering_by_J._R._Lamarsh_and_A._J._Baratta/Chapter3.ipynb
+++ b/Introduction_to_Nuclear_Engineering_by_J._R._Lamarsh_and_A._J._Baratta/Chapter3.ipynb
diff --git a/_Introduction_to_Nuclear_Engineering_by_J._R._Lamarsh_and_A._J._Baratta/Chapter4.ipynb b/Introduction_to_Nuclear_Engineering_by_J._R._Lamarsh_and_A._J._Baratta/Chapter4.ipynb
index 8212531f..8212531f 100644
--- a/_Introduction_to_Nuclear_Engineering_by_J._R._Lamarsh_and_A._J._Baratta/Chapter4.ipynb
+++ b/Introduction_to_Nuclear_Engineering_by_J._R._Lamarsh_and_A._J._Baratta/Chapter4.ipynb
diff --git a/_Introduction_to_Nuclear_Engineering_by_J._R._Lamarsh_and_A._J._Baratta/Chapter5.ipynb b/Introduction_to_Nuclear_Engineering_by_J._R._Lamarsh_and_A._J._Baratta/Chapter5.ipynb
index 82525e71..82525e71 100644
--- a/_Introduction_to_Nuclear_Engineering_by_J._R._Lamarsh_and_A._J._Baratta/Chapter5.ipynb
+++ b/Introduction_to_Nuclear_Engineering_by_J._R._Lamarsh_and_A._J._Baratta/Chapter5.ipynb
diff --git a/_Introduction_to_Nuclear_Engineering_by_J._R._Lamarsh_and_A._J._Baratta/Chapter6.ipynb b/Introduction_to_Nuclear_Engineering_by_J._R._Lamarsh_and_A._J._Baratta/Chapter6.ipynb
index 97c98f94..97c98f94 100644
--- a/_Introduction_to_Nuclear_Engineering_by_J._R._Lamarsh_and_A._J._Baratta/Chapter6.ipynb
+++ b/Introduction_to_Nuclear_Engineering_by_J._R._Lamarsh_and_A._J._Baratta/Chapter6.ipynb
diff --git a/_Introduction_to_Nuclear_Engineering_by_J._R._Lamarsh_and_A._J._Baratta/Chapter7.ipynb b/Introduction_to_Nuclear_Engineering_by_J._R._Lamarsh_and_A._J._Baratta/Chapter7.ipynb
index e5f67c9d..e5f67c9d 100644
--- a/_Introduction_to_Nuclear_Engineering_by_J._R._Lamarsh_and_A._J._Baratta/Chapter7.ipynb
+++ b/Introduction_to_Nuclear_Engineering_by_J._R._Lamarsh_and_A._J._Baratta/Chapter7.ipynb
diff --git a/_Introduction_to_Nuclear_Engineering_by_J._R._Lamarsh_and_A._J._Baratta/Chapter8.ipynb b/Introduction_to_Nuclear_Engineering_by_J._R._Lamarsh_and_A._J._Baratta/Chapter8.ipynb
index 1a1ca78a..1a1ca78a 100644
--- a/_Introduction_to_Nuclear_Engineering_by_J._R._Lamarsh_and_A._J._Baratta/Chapter8.ipynb
+++ b/Introduction_to_Nuclear_Engineering_by_J._R._Lamarsh_and_A._J._Baratta/Chapter8.ipynb
diff --git a/_Introduction_to_Nuclear_Engineering_by_J._R._Lamarsh_and_A._J._Baratta/Chapter9.ipynb b/Introduction_to_Nuclear_Engineering_by_J._R._Lamarsh_and_A._J._Baratta/Chapter9.ipynb
index 4779f851..4779f851 100644
--- a/_Introduction_to_Nuclear_Engineering_by_J._R._Lamarsh_and_A._J._Baratta/Chapter9.ipynb
+++ b/Introduction_to_Nuclear_Engineering_by_J._R._Lamarsh_and_A._J._Baratta/Chapter9.ipynb
diff --git a/_Introduction_to_Nuclear_Engineering_by_J._R._Lamarsh_and_A._J._Baratta/screenshots/chapter10.png b/Introduction_to_Nuclear_Engineering_by_J._R._Lamarsh_and_A._J._Baratta/screenshots/chapter10.png
index ca0fe4ce..ca0fe4ce 100644
--- a/_Introduction_to_Nuclear_Engineering_by_J._R._Lamarsh_and_A._J._Baratta/screenshots/chapter10.png
+++ b/Introduction_to_Nuclear_Engineering_by_J._R._Lamarsh_and_A._J._Baratta/screenshots/chapter10.png
diff --git a/_Introduction_to_Nuclear_Engineering_by_J._R._Lamarsh_and_A._J._Baratta/screenshots/chapter11.png b/Introduction_to_Nuclear_Engineering_by_J._R._Lamarsh_and_A._J._Baratta/screenshots/chapter11.png
index 48036db1..48036db1 100644
--- a/_Introduction_to_Nuclear_Engineering_by_J._R._Lamarsh_and_A._J._Baratta/screenshots/chapter11.png
+++ b/Introduction_to_Nuclear_Engineering_by_J._R._Lamarsh_and_A._J._Baratta/screenshots/chapter11.png
diff --git a/_Introduction_to_Nuclear_Engineering_by_J._R._Lamarsh_and_A._J._Baratta/screenshots/chapter2.png b/Introduction_to_Nuclear_Engineering_by_J._R._Lamarsh_and_A._J._Baratta/screenshots/chapter2.png
index 3c50846a..3c50846a 100644
--- a/_Introduction_to_Nuclear_Engineering_by_J._R._Lamarsh_and_A._J._Baratta/screenshots/chapter2.png
+++ b/Introduction_to_Nuclear_Engineering_by_J._R._Lamarsh_and_A._J._Baratta/screenshots/chapter2.png
diff --git a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter10-ClassesAndObjects.ipynb b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter10-ClassesAndObjects.ipynb
index a8a6de1f..a8a6de1f 100755
--- a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter10-ClassesAndObjects.ipynb
+++ b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter10-ClassesAndObjects.ipynb
diff --git a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter10-ClassesAndObjects_1.ipynb b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter10-ClassesAndObjects_1.ipynb
index e0892960..e0892960 100755
--- a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter10-ClassesAndObjects_1.ipynb
+++ b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter10-ClassesAndObjects_1.ipynb
diff --git a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter11-ObjectInitializationAndClean-Up.ipynb b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter11-ObjectInitializationAndClean-Up.ipynb
index e75a9045..e75a9045 100755
--- a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter11-ObjectInitializationAndClean-Up.ipynb
+++ b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter11-ObjectInitializationAndClean-Up.ipynb
diff --git a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter11-ObjectInitializationAndClean-Up_1.ipynb b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter11-ObjectInitializationAndClean-Up_1.ipynb
index e8f510a1..e8f510a1 100755
--- a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter11-ObjectInitializationAndClean-Up_1.ipynb
+++ b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter11-ObjectInitializationAndClean-Up_1.ipynb
diff --git a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter12-DynamicObjects.ipynb b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter12-DynamicObjects.ipynb
index 2c56060d..2c56060d 100755
--- a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter12-DynamicObjects.ipynb
+++ b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter12-DynamicObjects.ipynb
diff --git a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter12-DynamicObjects_1.ipynb b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter12-DynamicObjects_1.ipynb
index 2f8d1022..2f8d1022 100755
--- a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter12-DynamicObjects_1.ipynb
+++ b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter12-DynamicObjects_1.ipynb
diff --git a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter13-OperatorOverloading.ipynb b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter13-OperatorOverloading.ipynb
index 8c7b1cb8..8c7b1cb8 100755
--- a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter13-OperatorOverloading.ipynb
+++ b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter13-OperatorOverloading.ipynb
diff --git a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter13-OperatorOverloading_1.ipynb b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter13-OperatorOverloading_1.ipynb
index b67f9d8d..b67f9d8d 100755
--- a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter13-OperatorOverloading_1.ipynb
+++ b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter13-OperatorOverloading_1.ipynb
diff --git a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter14-Inheritance.ipynb b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter14-Inheritance.ipynb
index a617fa5c..a617fa5c 100755
--- a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter14-Inheritance.ipynb
+++ b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter14-Inheritance.ipynb
diff --git a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter14-Inheritance_1.ipynb b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter14-Inheritance_1.ipynb
index a617fa5c..a617fa5c 100755
--- a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter14-Inheritance_1.ipynb
+++ b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter14-Inheritance_1.ipynb
diff --git a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter15-VirtualFunctions.ipynb b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter15-VirtualFunctions.ipynb
index 885b9dee..885b9dee 100755
--- a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter15-VirtualFunctions.ipynb
+++ b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter15-VirtualFunctions.ipynb
diff --git a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter15-VirtualFunctions_1.ipynb b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter15-VirtualFunctions_1.ipynb
index ab3a16ad..ab3a16ad 100755
--- a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter15-VirtualFunctions_1.ipynb
+++ b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter15-VirtualFunctions_1.ipynb
diff --git a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter16-GenericProgrammingWithTemplates.ipynb b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter16-GenericProgrammingWithTemplates.ipynb
index 88641652..88641652 100755
--- a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter16-GenericProgrammingWithTemplates.ipynb
+++ b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter16-GenericProgrammingWithTemplates.ipynb
diff --git a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter16-GenericProgrammingWithTemplates_1.ipynb b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter16-GenericProgrammingWithTemplates_1.ipynb
index 2c0466e6..2c0466e6 100755
--- a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter16-GenericProgrammingWithTemplates_1.ipynb
+++ b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter16-GenericProgrammingWithTemplates_1.ipynb
diff --git a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter17-StreamsComputationWithConsole.ipynb b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter17-StreamsComputationWithConsole.ipynb
index 12c13cf7..12c13cf7 100755
--- a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter17-StreamsComputationWithConsole.ipynb
+++ b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter17-StreamsComputationWithConsole.ipynb
diff --git a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter17-StreamsComputationWithConsole_1.ipynb b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter17-StreamsComputationWithConsole_1.ipynb
index 12c13cf7..12c13cf7 100755
--- a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter17-StreamsComputationWithConsole_1.ipynb
+++ b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter17-StreamsComputationWithConsole_1.ipynb
diff --git a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter18-StreamsComputationWithFiles.ipynb b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter18-StreamsComputationWithFiles.ipynb
index d5aeb20b..d5aeb20b 100755
--- a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter18-StreamsComputationWithFiles.ipynb
+++ b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter18-StreamsComputationWithFiles.ipynb
diff --git a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter18-StreamsComputationWithFiles_1.ipynb b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter18-StreamsComputationWithFiles_1.ipynb
index c0ab891b..c0ab891b 100755
--- a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter18-StreamsComputationWithFiles_1.ipynb
+++ b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter18-StreamsComputationWithFiles_1.ipynb
diff --git a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter19-ExceptionHandling.ipynb b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter19-ExceptionHandling.ipynb
index 98576807..98576807 100755
--- a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter19-ExceptionHandling.ipynb
+++ b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter19-ExceptionHandling.ipynb
diff --git a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter19-ExceptionHandling_1.ipynb b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter19-ExceptionHandling_1.ipynb
index 98576807..98576807 100755
--- a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter19-ExceptionHandling_1.ipynb
+++ b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter19-ExceptionHandling_1.ipynb
diff --git a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter2-MovingFromCtoC++.ipynb b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter2-MovingFromCtoC++.ipynb
index a2a5c818..a2a5c818 100755
--- a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter2-MovingFromCtoC++.ipynb
+++ b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter2-MovingFromCtoC++.ipynb
diff --git a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter2-MovingfromCtoC++.ipynb b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter2-MovingfromCtoC++.ipynb
index 32b2a8e8..32b2a8e8 100755
--- a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter2-MovingfromCtoC++.ipynb
+++ b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter2-MovingfromCtoC++.ipynb
diff --git a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter3-C++AtAGlance.ipynb b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter3-C++AtAGlance.ipynb
index d81ed22a..d81ed22a 100755
--- a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter3-C++AtAGlance.ipynb
+++ b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter3-C++AtAGlance.ipynb
diff --git a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter3-C++AtAGlance_1.ipynb b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter3-C++AtAGlance_1.ipynb
index d81ed22a..d81ed22a 100755
--- a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter3-C++AtAGlance_1.ipynb
+++ b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter3-C++AtAGlance_1.ipynb
diff --git a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter4-DataTypes,OperatorsAndExpressions.ipynb b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter4-DataTypes,OperatorsAndExpressions.ipynb
index 1b95ba16..1b95ba16 100755
--- a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter4-DataTypes,OperatorsAndExpressions.ipynb
+++ b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter4-DataTypes,OperatorsAndExpressions.ipynb
diff --git a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter4-DataTypes,OperatorsAndExpressions_1.ipynb b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter4-DataTypes,OperatorsAndExpressions_1.ipynb
index 93c9b655..93c9b655 100755
--- a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter4-DataTypes,OperatorsAndExpressions_1.ipynb
+++ b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter4-DataTypes,OperatorsAndExpressions_1.ipynb
diff --git a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter5-ControlFlow.ipynb b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter5-ControlFlow.ipynb
index 9efd46c9..9efd46c9 100755
--- a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter5-ControlFlow.ipynb
+++ b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter5-ControlFlow.ipynb
diff --git a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter5-ControlFlow_1.ipynb b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter5-ControlFlow_1.ipynb
index 9efd46c9..9efd46c9 100755
--- a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter5-ControlFlow_1.ipynb
+++ b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter5-ControlFlow_1.ipynb
diff --git a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter6-ArraysAndStrings.ipynb b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter6-ArraysAndStrings.ipynb
index ce7a4137..ce7a4137 100755
--- a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter6-ArraysAndStrings.ipynb
+++ b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter6-ArraysAndStrings.ipynb
diff --git a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter6-ArraysAndStrings_1.ipynb b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter6-ArraysAndStrings_1.ipynb
index ce7a4137..ce7a4137 100755
--- a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter6-ArraysAndStrings_1.ipynb
+++ b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter6-ArraysAndStrings_1.ipynb
diff --git a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter7-ModularProgrammingWithFunctions.ipynb b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter7-ModularProgrammingWithFunctions.ipynb
index 209d4a32..209d4a32 100755
--- a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter7-ModularProgrammingWithFunctions.ipynb
+++ b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter7-ModularProgrammingWithFunctions.ipynb
diff --git a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter7-ModularProgrammingWithFunctions_1.ipynb b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter7-ModularProgrammingWithFunctions_1.ipynb
index 209d4a32..209d4a32 100755
--- a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter7-ModularProgrammingWithFunctions_1.ipynb
+++ b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter7-ModularProgrammingWithFunctions_1.ipynb
diff --git a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter8-StructuresAndUnions.ipynb b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter8-StructuresAndUnions.ipynb
index 88f0f80d..88f0f80d 100755
--- a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter8-StructuresAndUnions.ipynb
+++ b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter8-StructuresAndUnions.ipynb
diff --git a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter8-StructuresAndUnions_1.ipynb b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter8-StructuresAndUnions_1.ipynb
index 709caeac..709caeac 100755
--- a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter8-StructuresAndUnions_1.ipynb
+++ b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter8-StructuresAndUnions_1.ipynb
diff --git a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter9-PointersAndRuntimeBinding.ipynb b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter9-PointersAndRuntimeBinding.ipynb
index e3624032..e3624032 100755
--- a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter9-PointersAndRuntimeBinding.ipynb
+++ b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter9-PointersAndRuntimeBinding.ipynb
diff --git a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter9-PointersAndRuntimeBinding_1.ipynb b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter9-PointersAndRuntimeBinding_1.ipynb
index 1e90b1ef..1e90b1ef 100755
--- a/_Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter9-PointersAndRuntimeBinding_1.ipynb
+++ b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/Chapter9-PointersAndRuntimeBinding_1.ipynb
diff --git a/_Mastering_C++/README.txt b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/README.txt
index 3c39544d..3c39544d 100755
--- a/_Mastering_C++/README.txt
+++ b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/README.txt
diff --git a/_Mastering_C++/screenshots/1.png b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/screenshots/1.png
index df574903..df574903 100755
--- a/_Mastering_C++/screenshots/1.png
+++ b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/screenshots/1.png
diff --git a/_Mastering_C++/screenshots/2.png b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/screenshots/2.png
index 4a37be2b..4a37be2b 100755
--- a/_Mastering_C++/screenshots/2.png
+++ b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/screenshots/2.png
diff --git a/_Mastering_C++/screenshots/3.png b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/screenshots/3.png
index 8e1713ff..8e1713ff 100755
--- a/_Mastering_C++/screenshots/3.png
+++ b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/screenshots/3.png
diff --git a/_Mastering_C++/screenshots/IMG-20150614-WA0001.png b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/screenshots/IMG-20150614-WA0001.png
index 469c12fc..469c12fc 100755
--- a/_Mastering_C++/screenshots/IMG-20150614-WA0001.png
+++ b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/screenshots/IMG-20150614-WA0001.png
diff --git a/_Mastering_C++/screenshots/IMG-20150614-WA0006.png b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/screenshots/IMG-20150614-WA0006.png
index 00aa17a6..00aa17a6 100755
--- a/_Mastering_C++/screenshots/IMG-20150614-WA0006.png
+++ b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/screenshots/IMG-20150614-WA0006.png
diff --git a/_Mastering_C++/screenshots/IMG-20150619-WA0002.png b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/screenshots/IMG-20150619-WA0002.png
index fc13fe9c..fc13fe9c 100755
--- a/_Mastering_C++/screenshots/IMG-20150619-WA0002.png
+++ b/Mastering_C++_by_K_R_Venugopal_and_Rajkumar_Buyya/screenshots/IMG-20150619-WA0002.png
diff --git a/_Optical_Fiber_Communication_by_V._S._Bagad/Chapter01-Fiber_Optics_Communications_System.ipynb b/Optical_Fiber_Communication_by_V._S._Bagad/Chapter01-Fiber_Optics_Communications_System.ipynb
index ec323da9..ec323da9 100755
--- a/_Optical_Fiber_Communication_by_V._S._Bagad/Chapter01-Fiber_Optics_Communications_System.ipynb
+++ b/Optical_Fiber_Communication_by_V._S._Bagad/Chapter01-Fiber_Optics_Communications_System.ipynb
diff --git a/_Optical_Fiber_Communication_by_V._S._Bagad/Chapter02-Optical_Fiber_for_Telecommunication.ipynb b/Optical_Fiber_Communication_by_V._S._Bagad/Chapter02-Optical_Fiber_for_Telecommunication.ipynb
index 46a8893c..46a8893c 100755
--- a/_Optical_Fiber_Communication_by_V._S._Bagad/Chapter02-Optical_Fiber_for_Telecommunication.ipynb
+++ b/Optical_Fiber_Communication_by_V._S._Bagad/Chapter02-Optical_Fiber_for_Telecommunication.ipynb
diff --git a/_Optical_Fiber_Communication_by_V._S._Bagad/Chapter03-Optical_Sources_and_Transmitters.ipynb b/Optical_Fiber_Communication_by_V._S._Bagad/Chapter03-Optical_Sources_and_Transmitters.ipynb
index 1e7a6431..1e7a6431 100755
--- a/_Optical_Fiber_Communication_by_V._S._Bagad/Chapter03-Optical_Sources_and_Transmitters.ipynb
+++ b/Optical_Fiber_Communication_by_V._S._Bagad/Chapter03-Optical_Sources_and_Transmitters.ipynb
diff --git a/_Optical_Fiber_Communication_by_V._S._Bagad/Chapter04-Optical_Detectors_and_Receivers.ipynb b/Optical_Fiber_Communication_by_V._S._Bagad/Chapter04-Optical_Detectors_and_Receivers.ipynb
index 9dca6b9e..9dca6b9e 100755
--- a/_Optical_Fiber_Communication_by_V._S._Bagad/Chapter04-Optical_Detectors_and_Receivers.ipynb
+++ b/Optical_Fiber_Communication_by_V._S._Bagad/Chapter04-Optical_Detectors_and_Receivers.ipynb
diff --git a/_Optical_Fiber_Communication_by_V._S._Bagad/Chapter05-Design_Considerations_in_Optical_Links.ipynb b/Optical_Fiber_Communication_by_V._S._Bagad/Chapter05-Design_Considerations_in_Optical_Links.ipynb
index 3915a0b4..3915a0b4 100755
--- a/_Optical_Fiber_Communication_by_V._S._Bagad/Chapter05-Design_Considerations_in_Optical_Links.ipynb
+++ b/Optical_Fiber_Communication_by_V._S._Bagad/Chapter05-Design_Considerations_in_Optical_Links.ipynb
diff --git a/_Optical_Fiber_Communication_by_V._S._Bagad/Chapter1.ipynb b/Optical_Fiber_Communication_by_V._S._Bagad/Chapter1.ipynb
index ec323da9..ec323da9 100755
--- a/_Optical_Fiber_Communication_by_V._S._Bagad/Chapter1.ipynb
+++ b/Optical_Fiber_Communication_by_V._S._Bagad/Chapter1.ipynb
diff --git a/_Optical_Fiber_Communication_by_V._S._Bagad/Chapter2.ipynb b/Optical_Fiber_Communication_by_V._S._Bagad/Chapter2.ipynb
index 46a8893c..46a8893c 100755
--- a/_Optical_Fiber_Communication_by_V._S._Bagad/Chapter2.ipynb
+++ b/Optical_Fiber_Communication_by_V._S._Bagad/Chapter2.ipynb
diff --git a/_Optical_Fiber_Communication_by_V._S._Bagad/Chapter3.ipynb b/Optical_Fiber_Communication_by_V._S._Bagad/Chapter3.ipynb
index 1e7a6431..1e7a6431 100755
--- a/_Optical_Fiber_Communication_by_V._S._Bagad/Chapter3.ipynb
+++ b/Optical_Fiber_Communication_by_V._S._Bagad/Chapter3.ipynb
diff --git a/_Optical_Fiber_Communication_by_V._S._Bagad/Chapter4.ipynb b/Optical_Fiber_Communication_by_V._S._Bagad/Chapter4.ipynb
index 9dca6b9e..9dca6b9e 100755
--- a/_Optical_Fiber_Communication_by_V._S._Bagad/Chapter4.ipynb
+++ b/Optical_Fiber_Communication_by_V._S._Bagad/Chapter4.ipynb
diff --git a/_Optical_Fiber_Communication_by_V._S._Bagad/Chapter5.ipynb b/Optical_Fiber_Communication_by_V._S._Bagad/Chapter5.ipynb
index 3915a0b4..3915a0b4 100755
--- a/_Optical_Fiber_Communication_by_V._S._Bagad/Chapter5.ipynb
+++ b/Optical_Fiber_Communication_by_V._S._Bagad/Chapter5.ipynb
diff --git a/_Optical_Fiber_Communication_by_V._S._Bagad/Chapter6-Advanced_Optical_Systems.ipynb b/Optical_Fiber_Communication_by_V._S._Bagad/Chapter6-Advanced_Optical_Systems.ipynb
index b0cb88b7..b0cb88b7 100755
--- a/_Optical_Fiber_Communication_by_V._S._Bagad/Chapter6-Advanced_Optical_Systems.ipynb
+++ b/Optical_Fiber_Communication_by_V._S._Bagad/Chapter6-Advanced_Optical_Systems.ipynb
diff --git a/_Optical_Fiber_Communication_by_V._S._Bagad/Chapter6.ipynb b/Optical_Fiber_Communication_by_V._S._Bagad/Chapter6.ipynb
index b0cb88b7..b0cb88b7 100755
--- a/_Optical_Fiber_Communication_by_V._S._Bagad/Chapter6.ipynb
+++ b/Optical_Fiber_Communication_by_V._S._Bagad/Chapter6.ipynb
diff --git a/_Optical_Fiber_Communication_by_V._S._Bagad/README.txt b/Optical_Fiber_Communication_by_V._S._Bagad/README.txt
index 861c658f..861c658f 100755
--- a/_Optical_Fiber_Communication_by_V._S._Bagad/README.txt
+++ b/Optical_Fiber_Communication_by_V._S._Bagad/README.txt
diff --git a/_Optical_Fiber_Communication/screenshots/Chapter01-Ex1.7.1.png b/Optical_Fiber_Communication_by_V._S._Bagad/screenshots/Chapter01-Ex1.7.1.png
index 4c42636d..4c42636d 100755
--- a/_Optical_Fiber_Communication/screenshots/Chapter01-Ex1.7.1.png
+++ b/Optical_Fiber_Communication_by_V._S._Bagad/screenshots/Chapter01-Ex1.7.1.png
diff --git a/_Optical_Fiber_Communication/screenshots/Chapter02-Ex2.2.1.png b/Optical_Fiber_Communication_by_V._S._Bagad/screenshots/Chapter02-Ex2.2.1.png
index 7f5fd635..7f5fd635 100755
--- a/_Optical_Fiber_Communication/screenshots/Chapter02-Ex2.2.1.png
+++ b/Optical_Fiber_Communication_by_V._S._Bagad/screenshots/Chapter02-Ex2.2.1.png
diff --git a/_Optical_Fiber_Communication/screenshots/Chapter03-Ex3.2.1.png b/Optical_Fiber_Communication_by_V._S._Bagad/screenshots/Chapter03-Ex3.2.1.png
index c1f042e9..c1f042e9 100755
--- a/_Optical_Fiber_Communication/screenshots/Chapter03-Ex3.2.1.png
+++ b/Optical_Fiber_Communication_by_V._S._Bagad/screenshots/Chapter03-Ex3.2.1.png
diff --git a/Optical_Fiber_Communication_by_V._S._Bagad/screenshots/ch3.png b/Optical_Fiber_Communication_by_V._S._Bagad/screenshots/ch3.png
new file mode 100755
index 00000000..9adb53db
--- /dev/null
+++ b/Optical_Fiber_Communication_by_V._S._Bagad/screenshots/ch3.png
diff --git a/Optical_Fiber_Communication_by_V._S._Bagad/screenshots/ch3_1.png b/Optical_Fiber_Communication_by_V._S._Bagad/screenshots/ch3_1.png
new file mode 100755
index 00000000..9adb53db
--- /dev/null
+++ b/Optical_Fiber_Communication_by_V._S._Bagad/screenshots/ch3_1.png
diff --git a/Optical_Fiber_Communication_by_V._S._Bagad/screenshots/ch5.png b/Optical_Fiber_Communication_by_V._S._Bagad/screenshots/ch5.png
new file mode 100755
index 00000000..acf6fcac
--- /dev/null
+++ b/Optical_Fiber_Communication_by_V._S._Bagad/screenshots/ch5.png
diff --git a/Optical_Fiber_Communication_by_V._S._Bagad/screenshots/ch5_1.png b/Optical_Fiber_Communication_by_V._S._Bagad/screenshots/ch5_1.png
new file mode 100755
index 00000000..acf6fcac
--- /dev/null
+++ b/Optical_Fiber_Communication_by_V._S._Bagad/screenshots/ch5_1.png
diff --git a/Optical_Fiber_Communication_by_V._S._Bagad/screenshots/ch7.png b/Optical_Fiber_Communication_by_V._S._Bagad/screenshots/ch7.png
new file mode 100755
index 00000000..302231b6
--- /dev/null
+++ b/Optical_Fiber_Communication_by_V._S._Bagad/screenshots/ch7.png
diff --git a/Optical_Fiber_Communication_by_V._S._Bagad/screenshots/ch7_1.png b/Optical_Fiber_Communication_by_V._S._Bagad/screenshots/ch7_1.png
new file mode 100755
index 00000000..302231b6
--- /dev/null
+++ b/Optical_Fiber_Communication_by_V._S._Bagad/screenshots/ch7_1.png
diff --git a/_Optical_Fiber_Communication/screenshots/chapter2.png b/Optical_Fiber_Communication_by_V._S._Bagad/screenshots/chapter2.png
index e8ee191d..e8ee191d 100755
--- a/_Optical_Fiber_Communication/screenshots/chapter2.png
+++ b/Optical_Fiber_Communication_by_V._S._Bagad/screenshots/chapter2.png
diff --git a/_Optical_Fiber_Communication/screenshots/chapter5.png b/Optical_Fiber_Communication_by_V._S._Bagad/screenshots/chapter5.png
index d6fa34e3..d6fa34e3 100755
--- a/_Optical_Fiber_Communication/screenshots/chapter5.png
+++ b/Optical_Fiber_Communication_by_V._S._Bagad/screenshots/chapter5.png
diff --git a/_Optical_Fiber_Communication/screenshots/chapter6.png b/Optical_Fiber_Communication_by_V._S._Bagad/screenshots/chapter6.png
index ac19fe5b..ac19fe5b 100755
--- a/_Optical_Fiber_Communication/screenshots/chapter6.png
+++ b/Optical_Fiber_Communication_by_V._S._Bagad/screenshots/chapter6.png
diff --git a/Short_Course_by_e/hemla.ipynb b/Short_Course_by_e/hemla.ipynb
deleted file mode 100644
index 5cea9cb6..00000000
--- a/Short_Course_by_e/hemla.ipynb
+++ /dev/null
@@ -1,778 +0,0 @@
-{
- "metadata": {
-  "name": "",
-  "signature": "sha256:9826abe74c775578903ec0e922c705aacf445defe2dc3badb10ce4727f434663"
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter2-Compressible Flow with Friction and Heat: A Review"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Ex1-pg19"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "#what is the gas constant of air and density of air\n",
-      "import math\n",
-      "#intilization variable\n",
-      "p=3*10**6 ; #pressure in Pa\n",
-      "t=298. ; #temperatue in kelvin\n",
-      "mw= 29.; #molecular weight in kg/mol\n",
-      "ru=8314.; #universal constant in J/kmol.K\n",
-      "r=ru/mw ;\n",
-      "#using perfect gas law to get density:\n",
-      "rho=p/(r*t) ;\n",
-      "print'%s %.2f %s'%('Gas constant of air in',r,'J/kg.K')\n",
-      "print'%s %.1f %s'%('Density of air in',rho,'kg/m^3')"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Gas constant of air in 286.69 J/kg.K\n",
-        "Density of air in 35.1 kg/m^3\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Ex2-pg23"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "#find out the exit temperature and exit density by various methods \n",
-      "import math\n",
-      "t1=288.; #inlet temperture in Kelvin\n",
-      "p1=100*10**3; #inlet pressure in Pa\n",
-      "p2=1*10**6 #exit pressure in Pa\n",
-      "gma=1.4; #gamma.\n",
-      "rg=287.; #gas constant in J/kg.K\n",
-      "t2=t1*(p2/p1)**((gma-1)/gma);   #exit temperature \n",
-      "print'%s %.5f %s'%('Exit temperature in',t2,'K')\n",
-      "#first method to find exit density:\n",
-      "#application of perfect gas law at exit\n",
-      "rho=p2/(rg*t2); #rho= exit density.\n",
-      "print'%s %.7f %s'%('exit density at by method 1 in',rho,'kg/m^3')\n",
-      "#method 2: using isentropic relation between inlet and exit density.\n",
-      "rho1=p1/(rg*t1); #inlet density.\n",
-      "rho=rho1*(p2/p1)**(1/gma);\n",
-      "print'%s %.2f %s'%('exit density by method 2 in',rho,'kg/m^3')\n",
-      "\n",
-      "                                                     "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Exit temperature in 556.04095 K\n",
-        "exit density at by method 1 in 6.2663021 kg/m^3\n",
-        "exit density by method 2 in 6.27 kg/m^3\n"
-       ]
-      }
-     ],
-     "prompt_number": 2
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Ex3-pg25"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "#what is the rate of mass flow through exit \n",
-      "import math\n",
-      "d1=1.2 #inlet 1 density in kg/m^3.\n",
-      "u1=25. # inlet 1 veocity in m/s.\n",
-      "a1=0.25 #inlet 1 area in m^2.\n",
-      "d2=0.2 #inlet 2 density in kg/m^3.\n",
-      "u2=225. #inlet 2 velocity in m/s.\n",
-      "a2=0.10 #inlet 2 area in m^2.\n",
-      "m1=d1*a1*u1; #rate of mass flow entering inlet 1.\n",
-      "m2=d2*u2*a2; #rate of mass flow entering inlet 2.\n",
-      "#since total mass in=total mass out,\n",
-      "m3=m1+m2; #m3=rate of mass flow through exit.\n",
-      "print'%s %.f %s'%('Rate of mass flow through exit in',m3,' kg/s')\n",
-      "\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Rate of mass flow through exit in 12  kg/s\n"
-       ]
-      }
-     ],
-     "prompt_number": 4
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Ex4-pg27"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "#what is the axial force needed to support the plate and lateral force needed to support the plate\n",
-      "import math\n",
-      "u1=2 #speed of water going on the plate. X-component in m/s.\n",
-      "v1=0 #speed of water going on the plate. Y-component in m/s.\n",
-      "u2=1 #speed of water going on the plate. X-component in m/s.\n",
-      "v2=1.73 #speed of water going on the plate Y-coponent in m/s.\n",
-      "m=0.1 #rate of flow of mass of the water on the plate in kg/s.\n",
-      "#Using Newton's second law.\n",
-      "Fx=m*(u2-u1); #X-component of force exerted by water\n",
-      "print'%s %.1f %s'%('Axial force needed to support the plate in',Fx,'N')\n",
-      "Fy=m*(v2-v1); #Y-component of force exerted by water.\n",
-      "print'%s %.3f %s'%('Lateral force needed to support the plate in',Fy,'N')\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Axial force needed to support the plate in -0.1 N\n",
-        "Lateral force needed to support the plate in 0.173 N\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Ex5-pg29"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "#calculate the Exit total and static temperature \n",
-      "m=50 #mass flow rate in kg/s.\n",
-      "T1=298 #inlet temperature in K.\n",
-      "u1=150 #inlet velocity in m/s.\n",
-      "cp1=1004 #specific heat at constant pressure of inlet in J/kg.K.\n",
-      "gm=1.4 #gamma.\n",
-      "u2=400 # exit velocity in m/s.\n",
-      "cp2=1243. #specific heat at constant pressure of exit in J/kg.K.\n",
-      "q=42*10**6 #heat transfer rate in control volume in Watt.\n",
-      "me=-100*10**3 #mechanical power in Watt.\n",
-      "#first calculate total enthalpy at the inlet:\n",
-      "ht1=cp1*T1+(u1**2)/2; #ht1=Total inlet enthalpy.\n",
-      "#now applying conservation of energy equation:\n",
-      "ht2=ht1+((q-me)/m) #ht2=Total enthalpy at exit.\n",
-      "Tt2=ht2/cp2; #Tt2=Total exit temperature.\n",
-      "T2=Tt2-((u2**2)/(2*cp2)); #T2=static exit temperature.\n",
-      "print'%s %.5f %s'%('Exit total temperature in',Tt2,'K')\n",
-      "print'%s %.4f %s'%('Exit static temperature in',T2,'K')"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Exit total temperature in 927.14562 K\n",
-        "Exit static temperature in 862.7852 K\n"
-       ]
-      }
-     ],
-     "prompt_number": 6
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Ex6-pg65"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "#intilization variable\n",
-      "import math\n",
-      "d=0.2 #Diameter in meters.\n",
-      "M1=0.2 #inlet Mach no.\n",
-      "p1=100*10**3 #inlet pressure in Pa\n",
-      "Tt1=288. #total inlet temperature in K\n",
-      "q=100*10**3 #rate of heat transfer to fluid in Watt.\n",
-      "rg=287. #Gas constant in J/kg.K.\n",
-      "gm=1.4 #gamma\n",
-      "#(a)inlet mass flow:\n",
-      "m=((gm/rg)**(1./2.))*(p1/(Tt1)**(1./2.))*3.14*(d*d)/4.*(M1/(1.+((gm-1.)/2.)*(M1**2.))**((gm+1.)/(2.*(gm-1.))));\n",
-      "\n",
-      "#(b)\n",
-      "qm=q/m; #Heat per unit mass.\n",
-      "#Tt1/Tcr=0.1736, pt1/Pcr=1.2346, ((Delta(s)/R)1=6.3402,p1/Pcr=2.2727)\n",
-      "Tcr=Tt1/0.1736;\n",
-      "\n",
-      "Pcr=p1/2.2727;\n",
-      "#From energy equation:\n",
-      "cp=(gm/(gm-1.))*rg;\n",
-      "Tt2=Tt1+(q/cp);\n",
-      "q1cr=cp*(Tcr-Tt1)/1000.;\n",
-      "M2=0.22;\n",
-      "#From table : pt2/Pcr=1.2281, (Delta(s)/R)2=5.7395, p2/Pcr=2.2477.\n",
-      "#The percent total pressure drop is (((pt1/Pcr)-(pt2/Pcr))/(pt1/Pcr))*100.\n",
-      "p2=2.2477*Pcr;\n",
-      "dp=((1.2346-1.2281)/1.2346)*100;\n",
-      "#Entropy rise is the difference between (delta(s)/R)1 and (delta(s)/R)2.\n",
-      "ds=6.3402-5.7395;\n",
-      "#Static pressure drop in duct due to heat transfer is\n",
-      "dps=((p1/Pcr)-(p2/Pcr))*Pcr/1000.;\n",
-      "print'%s %.7f %s'%('Mass flow rate through duct in',m,'kg/s')\n",
-      "print'%s %.4f %s'%('Critical heat flux that would choke the duct for the M1 in',q1cr,'kJ/kg')\n",
-      "print'%s %.2f %s'%('The exit Mach No.',M2,'')\n",
-      "print'%s %.7f %s'%('The percent total pressure loss',dp,'%')\n",
-      "print'%s %.4f %s'%('The entropy rise',ds,'')\n",
-      "print'%s %.7f %s'%('The static pressure drop in ',dps,'kPa')"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Mass flow rate through duct in 2.5235091 kg/s\n",
-        "Critical heat flux that would choke the duct for the M1 in 1377.1556 kJ/kg\n",
-        "The exit Mach No. 0.22 \n",
-        "The percent total pressure loss 0.5264863 %\n",
-        "The entropy rise 0.6007 \n",
-        "The static pressure drop in  1.1000132 kPa\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Ex7-pg67"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "#what is total exit temperautre if exit is choked and maximum heat released and fule to air ratio to thermally choke the combustor exit and total pressure loss\n",
-      "#intilization variable\n",
-      "import math\n",
-      "M1=3.0 ##Mach no. at inlet\n",
-      "pt1=45*10**3 ##Total pressure t inlet in Pa\n",
-      "Tt1=1800 ##Total temperature at inlet in K\n",
-      "hv=12000 ##Lower heating value of hydrogen kJ/kg\n",
-      "gm=1.3 ##gamma\n",
-      "R=0.287 ##in kJ/kg.K\n",
-      "##Using RAYLEIGH table for M1=3.0 and gamma=1.3, we get Tt1/Tcr=0.6032, pt1/Pcr=4.0073.\n",
-      "Tcr=Tt1/0.6032\n",
-      "Pcr=pt1/4.0073\n",
-      "##if exit is choked, Tt2=Tcr\n",
-      "Tt2=Tt1/0.6032;\n",
-      "cp=gm*R/(gm-1);\n",
-      "##Energy balance across burner:\n",
-      "Q1cr=cp*(Tcr-Tt1);\n",
-      "f=(Q1cr/120000);\n",
-      "##total pressure loss:\n",
-      "dpt=1-Pcr/pt1;\n",
-      "print'%s %.4f %s'%('Total exit temperature if exit is choked in',Tt2,'K')\n",
-      "print'%s %.4f %s'%('Maximum heat released per unit mass of air in',Q1cr, 'kJ/kg')\n",
-      "print'%s %.7f %s'%('fuel-to-air ratio to thermally choke the combustor exit',f,'')\n",
-      "print'%s %.7f %s'%('Total pressure loss (in fraction)',dpt,'')\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Total exit temperature if exit is choked in 2984.0849 K\n",
-        "Maximum heat released per unit mass of air in 1472.6069 kJ/kg\n",
-        "fuel-to-air ratio to thermally choke the combustor exit 0.0122717 \n",
-        "Total pressure loss (in fraction) 0.7504554 \n"
-       ]
-      }
-     ],
-     "prompt_number": 8
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Ex8-pg67"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "#calculate the new inlet mach no and spilled flow at the inlet\n",
-      "#initilization variable \n",
-      "import math\n",
-      "Tt1=50.+460. ##Converting the inlet temp. to the absolute scale i.e. in degree R\n",
-      "M1=0.5 ##Initial inlet Mach no.\n",
-      "pt1=14.7 ##Units in psia\n",
-      "gm=1.4 ##gamma\n",
-      "R=53.34 ##units in ft.lbf/lbm.degree R\n",
-      "Tcr=Tt1/0.69136 \n",
-      "cp=gm*R/(gm-1)\n",
-      "##using energy equation:\n",
-      "Q1cr=cp*(Tcr-Tt1)\n",
-      "##since heat flux is 1.2(Q1cr).\n",
-      "q=1.2*Q1cr\n",
-      "Tt1cr1=Tt1+(Q1cr/cp) ##new exit total temp.\n",
-      "z=Tt1/Tt1cr1\n",
-      "M2=0.473\n",
-      "\n",
-      "f=M1/(1+((gm-1)/2)*M1**2)**((gm+1)/(2*(gm-1)))\n",
-      "\n",
-      "sm=((f*(M1)-f*(M2))/f*(M1))*100. ##sm=The % spilled flow at the inlet\n",
-      "print'%s %.5f %s'%('The new inlet Mach no.',M2,'')\n",
-      "print'%s %.5f %s'%('The % spilled flow at the inlet',sm,'')\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The new inlet Mach no. 0.47300 \n",
-        "The % spilled flow at the inlet 1.35000 \n"
-       ]
-      }
-     ],
-     "prompt_number": 9
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Ex9-pg76"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "#intilization variable\n",
-      "#calculate choking length abd exit mach no and total pressure loss and the static pressure and impulse due to friction \n",
-      "import math\n",
-      "d=0.2 ##diameter in meters.\n",
-      "l=0.2 ##length in meters.\n",
-      "Cf=0.005 ##average wall friction coefficient.\n",
-      "M1=0.24 ##inlet mach no.\n",
-      "gm=1.4 ##gamma.\n",
-      "##From FANNO tbale\n",
-      "L1cr=(9.3866*d/2)/(4*Cf);\n",
-      "L2cr=L1cr-l;\n",
-      "##from FANNO table\n",
-      "M2=0.3;\n",
-      "x=2.4956;\n",
-      "y=2.0351;\n",
-      "a=4.5383;\n",
-      "b=3.6191;\n",
-      "i1=2.043;\n",
-      "i2=1.698;\n",
-      "##% total pressure drop due to friction:\n",
-      "dpt=(x-y)/(x)*100;\n",
-      "##static pressur drop:\n",
-      "dps=(a-b)/a*100;\n",
-      "##Loss pf fluid:\n",
-      "lf=(i2-i1);\n",
-      "print'%s %.3f %s'%('The choking length of duct in',L1cr,'m')\n",
-      "print'%s %.1f %s'%('The exit Mach no.',M2,'')\n",
-      "print'%s %.6f %s'%('% total pressure loss',dpt,'')\n",
-      "print'%s %.5f %s'%('The static pressure drop in',dps,'%')\n",
-      "print'%s %.3f %s'%('Loss of impulse due to friction(I* times)',lf,'')\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The choking length of duct in 46.933 m\n",
-        "The exit Mach no. 0.3 \n",
-        "% total pressure loss 18.452476 \n",
-        "The static pressure drop in 20.25428 %\n",
-        "Loss of impulse due to friction(I* times) -0.345 \n"
-       ]
-      }
-     ],
-     "prompt_number": 10
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Ex10-pg77"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "#initilization variable\n",
-      "import math \n",
-      "#caluclate maximum length of the duct that will support given in inlet condition and the new inlet condition and flow drop \n",
-      "M1=0.5\n",
-      "a=2. ## area of cross section units in cm^2\n",
-      "Cf=0.005 ##coefficient of skin friction\n",
-      "gm=1.4 ##gamma\n",
-      "##Calculations\n",
-      "c=2.*(2.+1.); ##Parameter of surface.\n",
-      "##From FANNO table: 4*Cf*L1cr/Dh=1.0691;\n",
-      "Dh=4.*a/c; ##Hydrolic diameter.\n",
-      "L1cr=1.069*Dh/(4.*Cf);\n",
-      "##maximum length will be L1cr.\n",
-      "##For new length(i.e. 2.16*L1cr), Mach no. M2 from FANNO table, M2=0.4;.\n",
-      "M2=0.4;\n",
-      "##the inlet total pressue and temp remains the same, therefore the mass flow rate in the duct is proportional to f(M):\n",
-      "\n",
-      "f=0.5/(1.+((gm-1.)/2.)*0.5**2.)**((gm+1.)/(2.*(gm-1.)))\n",
-      "#endfunction\n",
-      "dm=(f*(M1)-f*(M2))/f*(M1)*100.+10;\n",
-      "print'%s %.3f %s'%(\"(a)Maximum length of duct that will support given inlet condition(in cm):\",L1cr,\"\")\n",
-      "print'%s %.3f %s'%(\"(b)The new inlet condition mach no. M2:\",M2,\"\")\n",
-      "print'%s %.3f %s'%(\"(c)% inlet mass flow drop due to the longer length of the duct:\",dm,\"\")\n",
-      "\n",
-      "\n",
-      "\n",
-      "\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "(a)Maximum length of duct that will support given inlet condition(in cm): 71.267 \n",
-        "(b)The new inlet condition mach no. M2: 0.400 \n",
-        "(c)% inlet mass flow drop due to the longer length of the duct: 15.000 \n"
-       ]
-      }
-     ],
-     "prompt_number": 11
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Ex11-pg78"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "import numpy\n",
-      "M1=0.7;\n",
-      "dpt=0.99; ##pt2/pt1=dpt.\n",
-      "gm=1.4; ##gamma\n",
-      "A2=1.237 \n",
-      "a=1/1.237;\n",
-      "import warnings\n",
-      "warnings.filterwarnings('ignore')\n",
-      "##Calculations:\n",
-      "\n",
-      "k=(1./dpt)*(a)*(M1/(1.+(0.2*(M1)**2.))**3.);\n",
-      "po=([k*0.008,0,k*.12,0,k*.6,-1,k])\n",
-      "W=numpy.roots(po)\n",
-      "i=0;\n",
-      "s=1;\n",
-      "M2=W[4]\n",
-      "print -M2,\"(a)The exit Mach no. M2:\"\n",
-      "\n",
-      "\n",
-      "##p=p2/p1 i.e. static pressure ratio\n",
-      "p=dpt*((1.+(gm-1.)*(M1)**2./2.)/(1.+(gm-1.)*(M2)**2./2.))**(gm/(gm-1.))\n",
-      "##disp(p)\n",
-      "Cpr=(2./(gm*(M1)**2.))*(p-1.) ##Cpr is static pressure recovery : (p2-p1)/q1.\n",
-      "print\"%s %.2f %s\"%(\"(b)The static pressure recovery in the diffuser:\",-Cpr,\"\")\n",
-      "##Change in fluid impulse:\n",
-      "##Fxwalls=I2-I1=A1p1(1+gm*M1**2)-A2p2(1+gm*M2**2)\n",
-      "##Let, u=Fxwall/(p1*A1)\n",
-      "u=1.+gm*(M1)**2.-(1.237)*(p)*(1.+(gm*(M2)**2.))\n",
-      "print\"%s %.2f %s\"%(\"(c)The force acting on the diffuser inner wall nondimensionalized by inlet static pressure and area:\",-u,\"\")\n",
-      "\n",
-      "\n",
-      "\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "(-1.70274823568-0j) (a)The exit Mach no. M2:\n",
-        "(b)The static pressure recovery in the diffuser: 2.11 \n",
-        "(c)The force acting on the diffuser inner wall nondimensionalized by inlet static pressure and area: 0.05 \n"
-       ]
-      }
-     ],
-     "prompt_number": 2
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Ex13-pg85"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "print \"Example2.13\"\n",
-      "import numpy\n",
-      "M1=0.5 #inlet mach no.\n",
-      "p=10. #(p=pt1/p0) whaere pt1 is inlet total pressure and p0 is ambient pressure.\n",
-      "dpc=0.01 #dpc=(pt1-Pth)/pt1 i.e. total pressure loss in convergant section\n",
-      "f=0.99 #f=Pth/pt1\n",
-      "dpd=0.02 #dpd=(Pth-pt2)/Pth i.e. total pressure loss in the divergent section\n",
-      "j=1/0.98 #j=Pth/pt2\n",
-      "A=2. #a=A2/Ath. nozzle area expansion ratio.\n",
-      "gm=1.4 # gamma\n",
-      "R=287. #J/kg.K universal gas constant.\n",
-      "#Calculations:\n",
-      "#\"th\"\" subscript denotes throat.\n",
-      "Mth=1. #mach no at thorat is always 1.\n",
-      "\n",
-      "k=(j)*(1./A)*(Mth/(1+(0.2*(Mth)**2))**3)\n",
-      "po=([k*0.008,0,k*.12,0,k*.6,-1,k])\n",
-      "W=numpy.roots(po)\n",
-      "i=0;\n",
-      "s=1;\n",
-      "M2=W[4]\n",
-      "print M2,\"(a)The exit Mach no. M2:\"\n",
-      "#p2/pt2=1/(1+(gm-1)/2*M2**2)**(gm/(gm-1)) \n",
-      "#pt2=(pt2/Pth)*(Pth/pt1)*(pt1/p0)*p0\n",
-      "#let pr=p2/p0\n",
-      "pr=((1/j)*f*p)/(1+(0.2*(M2)**2))**(gm/(gm-1))\n",
-      "\n",
-      "print pr,\"(b)The exit static pressure in terms of ambient pressure p2/p0:\"#Fxwall=-Fxliquid=I1-I2\n",
-      "\n",
-      "#let r=A1/Ath\n",
-      "r=(f)*(1/M1)*(((1+((gm-1)/2)*(M1)**2)/((gm+1)/2))**((gm+1)/(2*(gm-1))))\n",
-      "#disp(r)\n",
-      "#Psth is throat static pressure.\n",
-      "#z1=Psth/pt1=f/((gm+1)/2)**(gm/(gm-1))\n",
-      "z1=f/((gm+1)/2)**(gm/(gm-1))\n",
-      "#disp(z1)\n",
-      "#p1 is static pressure at inlet\n",
-      "#s1=p1/pt1\n",
-      "s1=1/(1+((gm-1)/2)*(M1)**2)**(gm/(gm-1))\n",
-      "#disp(s1)\n",
-      "#let y=Fxcwall/(Ath*pt1), where Fxwall is Fx converging-wall\n",
-      "y=s1*r*(1+(gm*(M1)**2))-(z1*(1+(gm*(Mth)**2)))\n",
-      "print y,\"(c)The nondimensional axial force acting on the convergent nozzle:\"\n",
-      "#similarly finding nondimensional force on the nozzle DIVERGENT section\n",
-      "#y1=Fxdiv-wall/Ath*pt1\n",
-      "#f1=p2/pt1\n",
-      "f1=pr*(1/p)\n",
-      "#disp(f1)\n",
-      "y1=z1*(1+(gm*(Mth)**2))-f1*A*(1+(gm*(M2)**2))\n",
-      "print y1,\"(d)The nondimensional axial force acting on the divergent nozzle:\"\n",
-      "#total axial force acting on nozzle wall: Fsum=y+y1\n",
-      "Fsum=y+y1\n",
-      "print Fsum,\"(e)The total axial force(nondimensional) acting on the nozzle: \""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Example2.13\n",
-        "(2.17433864456+0j) (a)The exit Mach no. M2:\n",
-        "(0.944524245306+0j) (b)The exit static pressure in terms of ambient pressure p2/p0:\n",
-        "0.254397897726 (c)The nondimensional axial force acting on the convergent nozzle:\n",
-        "(-0.184039795857+0j) (d)The nondimensional axial force acting on the divergent nozzle:\n",
-        "(0.070358101869+0j) (e)The total axial force(nondimensional) acting on the nozzle: \n"
-       ]
-      }
-     ],
-     "prompt_number": 13
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Ex14-pg87"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "#calculate non dimensional axial force and negative sign on the axial force experienced by the compressor \n",
-      "p=20. ##p=p2/p1 i.e. compression ratio.\n",
-      "gm=1.4 ## gamma\n",
-      "##Vx1=Vx2 i.e. axial velocity remains same.\n",
-      "##calculations:\n",
-      "d=p**(1/gm) ##d=d2/d1 i.e. density ratio\n",
-      "A=1./d ## A=A2/A1 i.e. area ratio which is related to density ratio as: A2/A1=d1/d2.\n",
-      "##disp(A)\n",
-      "Fx=1.-p*A  ##Fx=Fxwall/p1*A1 i.e nondimensional axial force.\n",
-      "print'%s %.7f %s'%(\"The non-dimensional axial force is :\",Fx,\"\")\n",
-      "print'%s %.f %s'%(\"The negative sign on the axial force experienced by the compressor structure signifies a thrust production by this component.\",Fx,\" \")"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The non-dimensional axial force is : -1.3535469 \n",
-        "The negative sign on the axial force experienced by the compressor structure signifies a thrust production by this component. -1  \n"
-       ]
-      }
-     ],
-     "prompt_number": 14
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Ex15-pg88"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "print(\"Example 2.15\")\n",
-      "t=1.8 ##t=T2/T1\n",
-      "d=1./t ##d=d2/d1 i.e. density ratio\n",
-      "v=1./d ##v=Vx2/Vx1 axial velocity ratio\n",
-      "ndaf=1.-(v) ##nondimensional axial force acting on the combustor walls\n",
-      "print'%s %.1f %s'%(\"The nondimensional axial force acting on the combustor walls:\",ndaf,\"\")\n",
-      "print(\"Negative sign signifies a thrust production by the device\")\n",
-      "\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Example 2.15\n",
-        "The nondimensional axial force acting on the combustor walls: -0.8 \n",
-        "Negative sign signifies a thrust production by the device\n"
-       ]
-      }
-     ],
-     "prompt_number": 15
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Ex16-pg89"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "print(\"Example 2.16\")\n",
-      "t=0.79 ##T2/T1 i.e. turbione expansion\n",
-      "gm=1.4 ##gamma\n",
-      "##calculations:\n",
-      "d=t**(1./(gm-1.))\n",
-      "##print'%s %.1f %s'%(d)\n",
-      "a=1./d ##area ratio\n",
-      "p=d**gm ##pressure ratio\n",
-      "ndaf=1.-p*a\n",
-      "print'%s %.2f %s'%(\"The nondimensional axial force:\",ndaf,\"\")"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Example 2.16\n",
-        "The nondimensional axial force: 0.21 \n"
-       ]
-      }
-     ],
-     "prompt_number": 16
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Short_Course_by_e/hemla_1.ipynb b/Short_Course_by_e/hemla_1.ipynb
deleted file mode 100644
index 5cea9cb6..00000000
--- a/Short_Course_by_e/hemla_1.ipynb
+++ /dev/null
@@ -1,778 +0,0 @@
-{
- "metadata": {
-  "name": "",
-  "signature": "sha256:9826abe74c775578903ec0e922c705aacf445defe2dc3badb10ce4727f434663"
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter2-Compressible Flow with Friction and Heat: A Review"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Ex1-pg19"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "#what is the gas constant of air and density of air\n",
-      "import math\n",
-      "#intilization variable\n",
-      "p=3*10**6 ; #pressure in Pa\n",
-      "t=298. ; #temperatue in kelvin\n",
-      "mw= 29.; #molecular weight in kg/mol\n",
-      "ru=8314.; #universal constant in J/kmol.K\n",
-      "r=ru/mw ;\n",
-      "#using perfect gas law to get density:\n",
-      "rho=p/(r*t) ;\n",
-      "print'%s %.2f %s'%('Gas constant of air in',r,'J/kg.K')\n",
-      "print'%s %.1f %s'%('Density of air in',rho,'kg/m^3')"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Gas constant of air in 286.69 J/kg.K\n",
-        "Density of air in 35.1 kg/m^3\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Ex2-pg23"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "#find out the exit temperature and exit density by various methods \n",
-      "import math\n",
-      "t1=288.; #inlet temperture in Kelvin\n",
-      "p1=100*10**3; #inlet pressure in Pa\n",
-      "p2=1*10**6 #exit pressure in Pa\n",
-      "gma=1.4; #gamma.\n",
-      "rg=287.; #gas constant in J/kg.K\n",
-      "t2=t1*(p2/p1)**((gma-1)/gma);   #exit temperature \n",
-      "print'%s %.5f %s'%('Exit temperature in',t2,'K')\n",
-      "#first method to find exit density:\n",
-      "#application of perfect gas law at exit\n",
-      "rho=p2/(rg*t2); #rho= exit density.\n",
-      "print'%s %.7f %s'%('exit density at by method 1 in',rho,'kg/m^3')\n",
-      "#method 2: using isentropic relation between inlet and exit density.\n",
-      "rho1=p1/(rg*t1); #inlet density.\n",
-      "rho=rho1*(p2/p1)**(1/gma);\n",
-      "print'%s %.2f %s'%('exit density by method 2 in',rho,'kg/m^3')\n",
-      "\n",
-      "                                                     "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Exit temperature in 556.04095 K\n",
-        "exit density at by method 1 in 6.2663021 kg/m^3\n",
-        "exit density by method 2 in 6.27 kg/m^3\n"
-       ]
-      }
-     ],
-     "prompt_number": 2
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Ex3-pg25"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "#what is the rate of mass flow through exit \n",
-      "import math\n",
-      "d1=1.2 #inlet 1 density in kg/m^3.\n",
-      "u1=25. # inlet 1 veocity in m/s.\n",
-      "a1=0.25 #inlet 1 area in m^2.\n",
-      "d2=0.2 #inlet 2 density in kg/m^3.\n",
-      "u2=225. #inlet 2 velocity in m/s.\n",
-      "a2=0.10 #inlet 2 area in m^2.\n",
-      "m1=d1*a1*u1; #rate of mass flow entering inlet 1.\n",
-      "m2=d2*u2*a2; #rate of mass flow entering inlet 2.\n",
-      "#since total mass in=total mass out,\n",
-      "m3=m1+m2; #m3=rate of mass flow through exit.\n",
-      "print'%s %.f %s'%('Rate of mass flow through exit in',m3,' kg/s')\n",
-      "\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Rate of mass flow through exit in 12  kg/s\n"
-       ]
-      }
-     ],
-     "prompt_number": 4
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Ex4-pg27"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "#what is the axial force needed to support the plate and lateral force needed to support the plate\n",
-      "import math\n",
-      "u1=2 #speed of water going on the plate. X-component in m/s.\n",
-      "v1=0 #speed of water going on the plate. Y-component in m/s.\n",
-      "u2=1 #speed of water going on the plate. X-component in m/s.\n",
-      "v2=1.73 #speed of water going on the plate Y-coponent in m/s.\n",
-      "m=0.1 #rate of flow of mass of the water on the plate in kg/s.\n",
-      "#Using Newton's second law.\n",
-      "Fx=m*(u2-u1); #X-component of force exerted by water\n",
-      "print'%s %.1f %s'%('Axial force needed to support the plate in',Fx,'N')\n",
-      "Fy=m*(v2-v1); #Y-component of force exerted by water.\n",
-      "print'%s %.3f %s'%('Lateral force needed to support the plate in',Fy,'N')\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Axial force needed to support the plate in -0.1 N\n",
-        "Lateral force needed to support the plate in 0.173 N\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Ex5-pg29"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "#calculate the Exit total and static temperature \n",
-      "m=50 #mass flow rate in kg/s.\n",
-      "T1=298 #inlet temperature in K.\n",
-      "u1=150 #inlet velocity in m/s.\n",
-      "cp1=1004 #specific heat at constant pressure of inlet in J/kg.K.\n",
-      "gm=1.4 #gamma.\n",
-      "u2=400 # exit velocity in m/s.\n",
-      "cp2=1243. #specific heat at constant pressure of exit in J/kg.K.\n",
-      "q=42*10**6 #heat transfer rate in control volume in Watt.\n",
-      "me=-100*10**3 #mechanical power in Watt.\n",
-      "#first calculate total enthalpy at the inlet:\n",
-      "ht1=cp1*T1+(u1**2)/2; #ht1=Total inlet enthalpy.\n",
-      "#now applying conservation of energy equation:\n",
-      "ht2=ht1+((q-me)/m) #ht2=Total enthalpy at exit.\n",
-      "Tt2=ht2/cp2; #Tt2=Total exit temperature.\n",
-      "T2=Tt2-((u2**2)/(2*cp2)); #T2=static exit temperature.\n",
-      "print'%s %.5f %s'%('Exit total temperature in',Tt2,'K')\n",
-      "print'%s %.4f %s'%('Exit static temperature in',T2,'K')"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Exit total temperature in 927.14562 K\n",
-        "Exit static temperature in 862.7852 K\n"
-       ]
-      }
-     ],
-     "prompt_number": 6
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Ex6-pg65"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "#intilization variable\n",
-      "import math\n",
-      "d=0.2 #Diameter in meters.\n",
-      "M1=0.2 #inlet Mach no.\n",
-      "p1=100*10**3 #inlet pressure in Pa\n",
-      "Tt1=288. #total inlet temperature in K\n",
-      "q=100*10**3 #rate of heat transfer to fluid in Watt.\n",
-      "rg=287. #Gas constant in J/kg.K.\n",
-      "gm=1.4 #gamma\n",
-      "#(a)inlet mass flow:\n",
-      "m=((gm/rg)**(1./2.))*(p1/(Tt1)**(1./2.))*3.14*(d*d)/4.*(M1/(1.+((gm-1.)/2.)*(M1**2.))**((gm+1.)/(2.*(gm-1.))));\n",
-      "\n",
-      "#(b)\n",
-      "qm=q/m; #Heat per unit mass.\n",
-      "#Tt1/Tcr=0.1736, pt1/Pcr=1.2346, ((Delta(s)/R)1=6.3402,p1/Pcr=2.2727)\n",
-      "Tcr=Tt1/0.1736;\n",
-      "\n",
-      "Pcr=p1/2.2727;\n",
-      "#From energy equation:\n",
-      "cp=(gm/(gm-1.))*rg;\n",
-      "Tt2=Tt1+(q/cp);\n",
-      "q1cr=cp*(Tcr-Tt1)/1000.;\n",
-      "M2=0.22;\n",
-      "#From table : pt2/Pcr=1.2281, (Delta(s)/R)2=5.7395, p2/Pcr=2.2477.\n",
-      "#The percent total pressure drop is (((pt1/Pcr)-(pt2/Pcr))/(pt1/Pcr))*100.\n",
-      "p2=2.2477*Pcr;\n",
-      "dp=((1.2346-1.2281)/1.2346)*100;\n",
-      "#Entropy rise is the difference between (delta(s)/R)1 and (delta(s)/R)2.\n",
-      "ds=6.3402-5.7395;\n",
-      "#Static pressure drop in duct due to heat transfer is\n",
-      "dps=((p1/Pcr)-(p2/Pcr))*Pcr/1000.;\n",
-      "print'%s %.7f %s'%('Mass flow rate through duct in',m,'kg/s')\n",
-      "print'%s %.4f %s'%('Critical heat flux that would choke the duct for the M1 in',q1cr,'kJ/kg')\n",
-      "print'%s %.2f %s'%('The exit Mach No.',M2,'')\n",
-      "print'%s %.7f %s'%('The percent total pressure loss',dp,'%')\n",
-      "print'%s %.4f %s'%('The entropy rise',ds,'')\n",
-      "print'%s %.7f %s'%('The static pressure drop in ',dps,'kPa')"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Mass flow rate through duct in 2.5235091 kg/s\n",
-        "Critical heat flux that would choke the duct for the M1 in 1377.1556 kJ/kg\n",
-        "The exit Mach No. 0.22 \n",
-        "The percent total pressure loss 0.5264863 %\n",
-        "The entropy rise 0.6007 \n",
-        "The static pressure drop in  1.1000132 kPa\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Ex7-pg67"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "#what is total exit temperautre if exit is choked and maximum heat released and fule to air ratio to thermally choke the combustor exit and total pressure loss\n",
-      "#intilization variable\n",
-      "import math\n",
-      "M1=3.0 ##Mach no. at inlet\n",
-      "pt1=45*10**3 ##Total pressure t inlet in Pa\n",
-      "Tt1=1800 ##Total temperature at inlet in K\n",
-      "hv=12000 ##Lower heating value of hydrogen kJ/kg\n",
-      "gm=1.3 ##gamma\n",
-      "R=0.287 ##in kJ/kg.K\n",
-      "##Using RAYLEIGH table for M1=3.0 and gamma=1.3, we get Tt1/Tcr=0.6032, pt1/Pcr=4.0073.\n",
-      "Tcr=Tt1/0.6032\n",
-      "Pcr=pt1/4.0073\n",
-      "##if exit is choked, Tt2=Tcr\n",
-      "Tt2=Tt1/0.6032;\n",
-      "cp=gm*R/(gm-1);\n",
-      "##Energy balance across burner:\n",
-      "Q1cr=cp*(Tcr-Tt1);\n",
-      "f=(Q1cr/120000);\n",
-      "##total pressure loss:\n",
-      "dpt=1-Pcr/pt1;\n",
-      "print'%s %.4f %s'%('Total exit temperature if exit is choked in',Tt2,'K')\n",
-      "print'%s %.4f %s'%('Maximum heat released per unit mass of air in',Q1cr, 'kJ/kg')\n",
-      "print'%s %.7f %s'%('fuel-to-air ratio to thermally choke the combustor exit',f,'')\n",
-      "print'%s %.7f %s'%('Total pressure loss (in fraction)',dpt,'')\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Total exit temperature if exit is choked in 2984.0849 K\n",
-        "Maximum heat released per unit mass of air in 1472.6069 kJ/kg\n",
-        "fuel-to-air ratio to thermally choke the combustor exit 0.0122717 \n",
-        "Total pressure loss (in fraction) 0.7504554 \n"
-       ]
-      }
-     ],
-     "prompt_number": 8
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Ex8-pg67"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "#calculate the new inlet mach no and spilled flow at the inlet\n",
-      "#initilization variable \n",
-      "import math\n",
-      "Tt1=50.+460. ##Converting the inlet temp. to the absolute scale i.e. in degree R\n",
-      "M1=0.5 ##Initial inlet Mach no.\n",
-      "pt1=14.7 ##Units in psia\n",
-      "gm=1.4 ##gamma\n",
-      "R=53.34 ##units in ft.lbf/lbm.degree R\n",
-      "Tcr=Tt1/0.69136 \n",
-      "cp=gm*R/(gm-1)\n",
-      "##using energy equation:\n",
-      "Q1cr=cp*(Tcr-Tt1)\n",
-      "##since heat flux is 1.2(Q1cr).\n",
-      "q=1.2*Q1cr\n",
-      "Tt1cr1=Tt1+(Q1cr/cp) ##new exit total temp.\n",
-      "z=Tt1/Tt1cr1\n",
-      "M2=0.473\n",
-      "\n",
-      "f=M1/(1+((gm-1)/2)*M1**2)**((gm+1)/(2*(gm-1)))\n",
-      "\n",
-      "sm=((f*(M1)-f*(M2))/f*(M1))*100. ##sm=The % spilled flow at the inlet\n",
-      "print'%s %.5f %s'%('The new inlet Mach no.',M2,'')\n",
-      "print'%s %.5f %s'%('The % spilled flow at the inlet',sm,'')\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The new inlet Mach no. 0.47300 \n",
-        "The % spilled flow at the inlet 1.35000 \n"
-       ]
-      }
-     ],
-     "prompt_number": 9
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Ex9-pg76"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "#intilization variable\n",
-      "#calculate choking length abd exit mach no and total pressure loss and the static pressure and impulse due to friction \n",
-      "import math\n",
-      "d=0.2 ##diameter in meters.\n",
-      "l=0.2 ##length in meters.\n",
-      "Cf=0.005 ##average wall friction coefficient.\n",
-      "M1=0.24 ##inlet mach no.\n",
-      "gm=1.4 ##gamma.\n",
-      "##From FANNO tbale\n",
-      "L1cr=(9.3866*d/2)/(4*Cf);\n",
-      "L2cr=L1cr-l;\n",
-      "##from FANNO table\n",
-      "M2=0.3;\n",
-      "x=2.4956;\n",
-      "y=2.0351;\n",
-      "a=4.5383;\n",
-      "b=3.6191;\n",
-      "i1=2.043;\n",
-      "i2=1.698;\n",
-      "##% total pressure drop due to friction:\n",
-      "dpt=(x-y)/(x)*100;\n",
-      "##static pressur drop:\n",
-      "dps=(a-b)/a*100;\n",
-      "##Loss pf fluid:\n",
-      "lf=(i2-i1);\n",
-      "print'%s %.3f %s'%('The choking length of duct in',L1cr,'m')\n",
-      "print'%s %.1f %s'%('The exit Mach no.',M2,'')\n",
-      "print'%s %.6f %s'%('% total pressure loss',dpt,'')\n",
-      "print'%s %.5f %s'%('The static pressure drop in',dps,'%')\n",
-      "print'%s %.3f %s'%('Loss of impulse due to friction(I* times)',lf,'')\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The choking length of duct in 46.933 m\n",
-        "The exit Mach no. 0.3 \n",
-        "% total pressure loss 18.452476 \n",
-        "The static pressure drop in 20.25428 %\n",
-        "Loss of impulse due to friction(I* times) -0.345 \n"
-       ]
-      }
-     ],
-     "prompt_number": 10
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Ex10-pg77"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "#initilization variable\n",
-      "import math \n",
-      "#caluclate maximum length of the duct that will support given in inlet condition and the new inlet condition and flow drop \n",
-      "M1=0.5\n",
-      "a=2. ## area of cross section units in cm^2\n",
-      "Cf=0.005 ##coefficient of skin friction\n",
-      "gm=1.4 ##gamma\n",
-      "##Calculations\n",
-      "c=2.*(2.+1.); ##Parameter of surface.\n",
-      "##From FANNO table: 4*Cf*L1cr/Dh=1.0691;\n",
-      "Dh=4.*a/c; ##Hydrolic diameter.\n",
-      "L1cr=1.069*Dh/(4.*Cf);\n",
-      "##maximum length will be L1cr.\n",
-      "##For new length(i.e. 2.16*L1cr), Mach no. M2 from FANNO table, M2=0.4;.\n",
-      "M2=0.4;\n",
-      "##the inlet total pressue and temp remains the same, therefore the mass flow rate in the duct is proportional to f(M):\n",
-      "\n",
-      "f=0.5/(1.+((gm-1.)/2.)*0.5**2.)**((gm+1.)/(2.*(gm-1.)))\n",
-      "#endfunction\n",
-      "dm=(f*(M1)-f*(M2))/f*(M1)*100.+10;\n",
-      "print'%s %.3f %s'%(\"(a)Maximum length of duct that will support given inlet condition(in cm):\",L1cr,\"\")\n",
-      "print'%s %.3f %s'%(\"(b)The new inlet condition mach no. M2:\",M2,\"\")\n",
-      "print'%s %.3f %s'%(\"(c)% inlet mass flow drop due to the longer length of the duct:\",dm,\"\")\n",
-      "\n",
-      "\n",
-      "\n",
-      "\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "(a)Maximum length of duct that will support given inlet condition(in cm): 71.267 \n",
-        "(b)The new inlet condition mach no. M2: 0.400 \n",
-        "(c)% inlet mass flow drop due to the longer length of the duct: 15.000 \n"
-       ]
-      }
-     ],
-     "prompt_number": 11
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Ex11-pg78"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "import numpy\n",
-      "M1=0.7;\n",
-      "dpt=0.99; ##pt2/pt1=dpt.\n",
-      "gm=1.4; ##gamma\n",
-      "A2=1.237 \n",
-      "a=1/1.237;\n",
-      "import warnings\n",
-      "warnings.filterwarnings('ignore')\n",
-      "##Calculations:\n",
-      "\n",
-      "k=(1./dpt)*(a)*(M1/(1.+(0.2*(M1)**2.))**3.);\n",
-      "po=([k*0.008,0,k*.12,0,k*.6,-1,k])\n",
-      "W=numpy.roots(po)\n",
-      "i=0;\n",
-      "s=1;\n",
-      "M2=W[4]\n",
-      "print -M2,\"(a)The exit Mach no. M2:\"\n",
-      "\n",
-      "\n",
-      "##p=p2/p1 i.e. static pressure ratio\n",
-      "p=dpt*((1.+(gm-1.)*(M1)**2./2.)/(1.+(gm-1.)*(M2)**2./2.))**(gm/(gm-1.))\n",
-      "##disp(p)\n",
-      "Cpr=(2./(gm*(M1)**2.))*(p-1.) ##Cpr is static pressure recovery : (p2-p1)/q1.\n",
-      "print\"%s %.2f %s\"%(\"(b)The static pressure recovery in the diffuser:\",-Cpr,\"\")\n",
-      "##Change in fluid impulse:\n",
-      "##Fxwalls=I2-I1=A1p1(1+gm*M1**2)-A2p2(1+gm*M2**2)\n",
-      "##Let, u=Fxwall/(p1*A1)\n",
-      "u=1.+gm*(M1)**2.-(1.237)*(p)*(1.+(gm*(M2)**2.))\n",
-      "print\"%s %.2f %s\"%(\"(c)The force acting on the diffuser inner wall nondimensionalized by inlet static pressure and area:\",-u,\"\")\n",
-      "\n",
-      "\n",
-      "\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "(-1.70274823568-0j) (a)The exit Mach no. M2:\n",
-        "(b)The static pressure recovery in the diffuser: 2.11 \n",
-        "(c)The force acting on the diffuser inner wall nondimensionalized by inlet static pressure and area: 0.05 \n"
-       ]
-      }
-     ],
-     "prompt_number": 2
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Ex13-pg85"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "print \"Example2.13\"\n",
-      "import numpy\n",
-      "M1=0.5 #inlet mach no.\n",
-      "p=10. #(p=pt1/p0) whaere pt1 is inlet total pressure and p0 is ambient pressure.\n",
-      "dpc=0.01 #dpc=(pt1-Pth)/pt1 i.e. total pressure loss in convergant section\n",
-      "f=0.99 #f=Pth/pt1\n",
-      "dpd=0.02 #dpd=(Pth-pt2)/Pth i.e. total pressure loss in the divergent section\n",
-      "j=1/0.98 #j=Pth/pt2\n",
-      "A=2. #a=A2/Ath. nozzle area expansion ratio.\n",
-      "gm=1.4 # gamma\n",
-      "R=287. #J/kg.K universal gas constant.\n",
-      "#Calculations:\n",
-      "#\"th\"\" subscript denotes throat.\n",
-      "Mth=1. #mach no at thorat is always 1.\n",
-      "\n",
-      "k=(j)*(1./A)*(Mth/(1+(0.2*(Mth)**2))**3)\n",
-      "po=([k*0.008,0,k*.12,0,k*.6,-1,k])\n",
-      "W=numpy.roots(po)\n",
-      "i=0;\n",
-      "s=1;\n",
-      "M2=W[4]\n",
-      "print M2,\"(a)The exit Mach no. M2:\"\n",
-      "#p2/pt2=1/(1+(gm-1)/2*M2**2)**(gm/(gm-1)) \n",
-      "#pt2=(pt2/Pth)*(Pth/pt1)*(pt1/p0)*p0\n",
-      "#let pr=p2/p0\n",
-      "pr=((1/j)*f*p)/(1+(0.2*(M2)**2))**(gm/(gm-1))\n",
-      "\n",
-      "print pr,\"(b)The exit static pressure in terms of ambient pressure p2/p0:\"#Fxwall=-Fxliquid=I1-I2\n",
-      "\n",
-      "#let r=A1/Ath\n",
-      "r=(f)*(1/M1)*(((1+((gm-1)/2)*(M1)**2)/((gm+1)/2))**((gm+1)/(2*(gm-1))))\n",
-      "#disp(r)\n",
-      "#Psth is throat static pressure.\n",
-      "#z1=Psth/pt1=f/((gm+1)/2)**(gm/(gm-1))\n",
-      "z1=f/((gm+1)/2)**(gm/(gm-1))\n",
-      "#disp(z1)\n",
-      "#p1 is static pressure at inlet\n",
-      "#s1=p1/pt1\n",
-      "s1=1/(1+((gm-1)/2)*(M1)**2)**(gm/(gm-1))\n",
-      "#disp(s1)\n",
-      "#let y=Fxcwall/(Ath*pt1), where Fxwall is Fx converging-wall\n",
-      "y=s1*r*(1+(gm*(M1)**2))-(z1*(1+(gm*(Mth)**2)))\n",
-      "print y,\"(c)The nondimensional axial force acting on the convergent nozzle:\"\n",
-      "#similarly finding nondimensional force on the nozzle DIVERGENT section\n",
-      "#y1=Fxdiv-wall/Ath*pt1\n",
-      "#f1=p2/pt1\n",
-      "f1=pr*(1/p)\n",
-      "#disp(f1)\n",
-      "y1=z1*(1+(gm*(Mth)**2))-f1*A*(1+(gm*(M2)**2))\n",
-      "print y1,\"(d)The nondimensional axial force acting on the divergent nozzle:\"\n",
-      "#total axial force acting on nozzle wall: Fsum=y+y1\n",
-      "Fsum=y+y1\n",
-      "print Fsum,\"(e)The total axial force(nondimensional) acting on the nozzle: \""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Example2.13\n",
-        "(2.17433864456+0j) (a)The exit Mach no. M2:\n",
-        "(0.944524245306+0j) (b)The exit static pressure in terms of ambient pressure p2/p0:\n",
-        "0.254397897726 (c)The nondimensional axial force acting on the convergent nozzle:\n",
-        "(-0.184039795857+0j) (d)The nondimensional axial force acting on the divergent nozzle:\n",
-        "(0.070358101869+0j) (e)The total axial force(nondimensional) acting on the nozzle: \n"
-       ]
-      }
-     ],
-     "prompt_number": 13
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Ex14-pg87"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "#calculate non dimensional axial force and negative sign on the axial force experienced by the compressor \n",
-      "p=20. ##p=p2/p1 i.e. compression ratio.\n",
-      "gm=1.4 ## gamma\n",
-      "##Vx1=Vx2 i.e. axial velocity remains same.\n",
-      "##calculations:\n",
-      "d=p**(1/gm) ##d=d2/d1 i.e. density ratio\n",
-      "A=1./d ## A=A2/A1 i.e. area ratio which is related to density ratio as: A2/A1=d1/d2.\n",
-      "##disp(A)\n",
-      "Fx=1.-p*A  ##Fx=Fxwall/p1*A1 i.e nondimensional axial force.\n",
-      "print'%s %.7f %s'%(\"The non-dimensional axial force is :\",Fx,\"\")\n",
-      "print'%s %.f %s'%(\"The negative sign on the axial force experienced by the compressor structure signifies a thrust production by this component.\",Fx,\" \")"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The non-dimensional axial force is : -1.3535469 \n",
-        "The negative sign on the axial force experienced by the compressor structure signifies a thrust production by this component. -1  \n"
-       ]
-      }
-     ],
-     "prompt_number": 14
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Ex15-pg88"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "print(\"Example 2.15\")\n",
-      "t=1.8 ##t=T2/T1\n",
-      "d=1./t ##d=d2/d1 i.e. density ratio\n",
-      "v=1./d ##v=Vx2/Vx1 axial velocity ratio\n",
-      "ndaf=1.-(v) ##nondimensional axial force acting on the combustor walls\n",
-      "print'%s %.1f %s'%(\"The nondimensional axial force acting on the combustor walls:\",ndaf,\"\")\n",
-      "print(\"Negative sign signifies a thrust production by the device\")\n",
-      "\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Example 2.15\n",
-        "The nondimensional axial force acting on the combustor walls: -0.8 \n",
-        "Negative sign signifies a thrust production by the device\n"
-       ]
-      }
-     ],
-     "prompt_number": 15
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Ex16-pg89"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "print(\"Example 2.16\")\n",
-      "t=0.79 ##T2/T1 i.e. turbione expansion\n",
-      "gm=1.4 ##gamma\n",
-      "##calculations:\n",
-      "d=t**(1./(gm-1.))\n",
-      "##print'%s %.1f %s'%(d)\n",
-      "a=1./d ##area ratio\n",
-      "p=d**gm ##pressure ratio\n",
-      "ndaf=1.-p*a\n",
-      "print'%s %.2f %s'%(\"The nondimensional axial force:\",ndaf,\"\")"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Example 2.16\n",
-        "The nondimensional axial force: 0.21 \n"
-       ]
-      }
-     ],
-     "prompt_number": 16
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Short_Course_by_e/screenshots/warning.png b/Short_Course_by_e/screenshots/warning.png
deleted file mode 100644
index 81a93724..00000000
--- a/Short_Course_by_e/screenshots/warning.png
+++ /dev/null
diff --git a/Short_Course_by_e/screenshots/warning_1.png b/Short_Course_by_e/screenshots/warning_1.png
deleted file mode 100644
index 81a93724..00000000
--- a/Short_Course_by_e/screenshots/warning_1.png
+++ /dev/null
diff --git a/Short_Course_by_e/screenshots/warning_2.png b/Short_Course_by_e/screenshots/warning_2.png
deleted file mode 100644
index 81a93724..00000000
--- a/Short_Course_by_e/screenshots/warning_2.png
+++ /dev/null
diff --git a/_Solid_State_Devices_by_B._S._Nair_and_S._R._Deepa/Chapter_10_SILICON_CONTROLLED_RECTIFIER.ipynb b/Solid_State_Devices_by_B._S._Nair_and_S._R._Deepa/Chapter_10_SILICON_CONTROLLED_RECTIFIER.ipynb
index 6410798f..6410798f 100755
--- a/_Solid_State_Devices_by_B._S._Nair_and_S._R._Deepa/Chapter_10_SILICON_CONTROLLED_RECTIFIER.ipynb
+++ b/Solid_State_Devices_by_B._S._Nair_and_S._R._Deepa/Chapter_10_SILICON_CONTROLLED_RECTIFIER.ipynb
diff --git a/_Solid_State_Devices_by_B._S._Nair_and_S._R._Deepa/Chapter_1_CRYSTAL_STRUCTURES.ipynb b/Solid_State_Devices_by_B._S._Nair_and_S._R._Deepa/Chapter_1_CRYSTAL_STRUCTURES.ipynb
index cd376de8..cd376de8 100755
--- a/_Solid_State_Devices_by_B._S._Nair_and_S._R._Deepa/Chapter_1_CRYSTAL_STRUCTURES.ipynb
+++ b/Solid_State_Devices_by_B._S._Nair_and_S._R._Deepa/Chapter_1_CRYSTAL_STRUCTURES.ipynb
diff --git a/_Solid_State_Devices_by_B._S._Nair_and_S._R._Deepa/Chapter_6_ELECTRICAL_BREAKDOWN_IN_PN_JUNCTIONS.ipynb b/Solid_State_Devices_by_B._S._Nair_and_S._R._Deepa/Chapter_6_ELECTRICAL_BREAKDOWN_IN_PN_JUNCTIONS.ipynb
index 95315558..95315558 100755
--- a/_Solid_State_Devices_by_B._S._Nair_and_S._R._Deepa/Chapter_6_ELECTRICAL_BREAKDOWN_IN_PN_JUNCTIONS.ipynb
+++ b/Solid_State_Devices_by_B._S._Nair_and_S._R._Deepa/Chapter_6_ELECTRICAL_BREAKDOWN_IN_PN_JUNCTIONS.ipynb
diff --git a/_Solid_State_Devices_by_B._S._Nair_and_S._R._Deepa/chapter_2_ENERGY_BAND_THEORY_OF_SOLIDS.ipynb b/Solid_State_Devices_by_B._S._Nair_and_S._R._Deepa/chapter_2_ENERGY_BAND_THEORY_OF_SOLIDS.ipynb
index 7b0ddd98..7b0ddd98 100755
--- a/_Solid_State_Devices_by_B._S._Nair_and_S._R._Deepa/chapter_2_ENERGY_BAND_THEORY_OF_SOLIDS.ipynb
+++ b/Solid_State_Devices_by_B._S._Nair_and_S._R._Deepa/chapter_2_ENERGY_BAND_THEORY_OF_SOLIDS.ipynb
diff --git a/_Solid_State_Devices_by_B._S._Nair_and_S._R._Deepa/chapter_3_CARRIER_TRANSPORT_IN_SEMICONDUCTOR.ipynb b/Solid_State_Devices_by_B._S._Nair_and_S._R._Deepa/chapter_3_CARRIER_TRANSPORT_IN_SEMICONDUCTOR.ipynb
index 2cc9b53b..2cc9b53b 100755
--- a/_Solid_State_Devices_by_B._S._Nair_and_S._R._Deepa/chapter_3_CARRIER_TRANSPORT_IN_SEMICONDUCTOR.ipynb
+++ b/Solid_State_Devices_by_B._S._Nair_and_S._R._Deepa/chapter_3_CARRIER_TRANSPORT_IN_SEMICONDUCTOR.ipynb
diff --git a/_Solid_State_Devices_by_B._S._Nair_and_S._R._Deepa/chapter_4__EXCESS_CARRIER_IN_SEMICONDUCTOR.ipynb b/Solid_State_Devices_by_B._S._Nair_and_S._R._Deepa/chapter_4__EXCESS_CARRIER_IN_SEMICONDUCTOR.ipynb
index 4b62aae8..4b62aae8 100755
--- a/_Solid_State_Devices_by_B._S._Nair_and_S._R._Deepa/chapter_4__EXCESS_CARRIER_IN_SEMICONDUCTOR.ipynb
+++ b/Solid_State_Devices_by_B._S._Nair_and_S._R._Deepa/chapter_4__EXCESS_CARRIER_IN_SEMICONDUCTOR.ipynb
diff --git a/_Solid_State_Devices_by_B._S._Nair_and_S._R._Deepa/chapter_5_PN_JUNCTION_DIODE.ipynb b/Solid_State_Devices_by_B._S._Nair_and_S._R._Deepa/chapter_5_PN_JUNCTION_DIODE.ipynb
index f92767c3..f92767c3 100755
--- a/_Solid_State_Devices_by_B._S._Nair_and_S._R._Deepa/chapter_5_PN_JUNCTION_DIODE.ipynb
+++ b/Solid_State_Devices_by_B._S._Nair_and_S._R._Deepa/chapter_5_PN_JUNCTION_DIODE.ipynb
diff --git a/_Solid_State_Devices_by_B._S._Nair_and_S._R._Deepa/chapter_7_BIPOLAR_JUNCTION_TRANSISTORB.ipynb b/Solid_State_Devices_by_B._S._Nair_and_S._R._Deepa/chapter_7_BIPOLAR_JUNCTION_TRANSISTORB.ipynb
index bbe984b6..bbe984b6 100755
--- a/_Solid_State_Devices_by_B._S._Nair_and_S._R._Deepa/chapter_7_BIPOLAR_JUNCTION_TRANSISTORB.ipynb
+++ b/Solid_State_Devices_by_B._S._Nair_and_S._R._Deepa/chapter_7_BIPOLAR_JUNCTION_TRANSISTORB.ipynb
diff --git a/_Solid_State_Devices_by_B._S._Nair_and_S._R._Deepa/chapter_8_THE_FIELD_EFFECT_TRANSISTOR.ipynb b/Solid_State_Devices_by_B._S._Nair_and_S._R._Deepa/chapter_8_THE_FIELD_EFFECT_TRANSISTOR.ipynb
index 0c2e0420..0c2e0420 100755
--- a/_Solid_State_Devices_by_B._S._Nair_and_S._R._Deepa/chapter_8_THE_FIELD_EFFECT_TRANSISTOR.ipynb
+++ b/Solid_State_Devices_by_B._S._Nair_and_S._R._Deepa/chapter_8_THE_FIELD_EFFECT_TRANSISTOR.ipynb
diff --git a/_Solid_State_Devices_by_B._S._Nair_and_S._R._Deepa/screenshots/Screen_Shot_2015-11-05_at_11.31.11_pm.png b/Solid_State_Devices_by_B._S._Nair_and_S._R._Deepa/screenshots/Screen_Shot_2015-11-05_at_11.31.11_pm.png
index 35e9d1ad..35e9d1ad 100755
--- a/_Solid_State_Devices_by_B._S._Nair_and_S._R._Deepa/screenshots/Screen_Shot_2015-11-05_at_11.31.11_pm.png
+++ b/Solid_State_Devices_by_B._S._Nair_and_S._R._Deepa/screenshots/Screen_Shot_2015-11-05_at_11.31.11_pm.png
diff --git a/_Solid_State_Devices_by_B._S._Nair_and_S._R._Deepa/screenshots/Screen_Shot_2015-11-05_at_11.32.51_pm.png b/Solid_State_Devices_by_B._S._Nair_and_S._R._Deepa/screenshots/Screen_Shot_2015-11-05_at_11.32.51_pm.png
index aa7eca54..aa7eca54 100755
--- a/_Solid_State_Devices_by_B._S._Nair_and_S._R._Deepa/screenshots/Screen_Shot_2015-11-05_at_11.32.51_pm.png
+++ b/Solid_State_Devices_by_B._S._Nair_and_S._R._Deepa/screenshots/Screen_Shot_2015-11-05_at_11.32.51_pm.png
diff --git a/_Solid_State_Devices_by_B._S._Nair_and_S._R._Deepa/screenshots/Screen_Shot_2015-11-05_at_11.33.45_pm.png b/Solid_State_Devices_by_B._S._Nair_and_S._R._Deepa/screenshots/Screen_Shot_2015-11-05_at_11.33.45_pm.png
index 161d6b04..161d6b04 100755
--- a/_Solid_State_Devices_by_B._S._Nair_and_S._R._Deepa/screenshots/Screen_Shot_2015-11-05_at_11.33.45_pm.png
+++ b/Solid_State_Devices_by_B._S._Nair_and_S._R._Deepa/screenshots/Screen_Shot_2015-11-05_at_11.33.45_pm.png
diff --git a/Test/README.txt b/Test/README.txt
deleted file mode 100755
index b9a36bc6..00000000
--- a/Test/README.txt
+++ /dev/null
@@ -1,10 +0,0 @@
-Contributed By: Hardik Ghaghada
-Course: mca
-College/Institute/Organization: FOSSEE - Indian Institute of Technology
-Department/Designation: Aerospace
-Book Title: Test
-Author: Subramanium & Brij Lal
-Publisher: McGraw Hill Education (India) Private Limited, New Delhi
-Year of publication: 2000
-Isbn: 2548872474
-Edition: 2nd
\ No newline at end of file
diff --git a/Test/chapter1.ipynb b/Test/chapter1.ipynb
deleted file mode 100755
index cf45a409..00000000
--- a/Test/chapter1.ipynb
+++ /dev/null
@@ -1,423 +0,0 @@
-{
- "metadata": {
-  "name": ""
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 1: Tension Comprssion and Shear"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.1, page no. 9"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "Find compressive stress and strain in the post\n",
-      "\"\"\"\n",
-      "\n",
-      "import math\n",
-      "\n",
-      "#initialisation\n",
-      "\n",
-      "d_1 = 4                 # inner diameter (inch)\n",
-      "d_2 = 4.5               #outer diameter (inch)\n",
-      "P = 26000               # pressure in pound\n",
-      "L = 16                  # Length of cylinder (inch)\n",
-      "my_del = 0.012             # shortening of post (inch)\n",
-      "\n",
-      "#calculation\n",
-      "A = (math.pi/4)*((d_2**2)-(d_1**2))     #Area (inch^2)\n",
-      "s = P/A                                 # stress\n",
-      "\n",
-      "print \"compressive stress in the post is \", round(s), \"psi\"\n",
-      "\n",
-      "e = my_del/L                            # strain\n",
-      "\n",
-      "print \"compressive strain in the post is %e\" %e"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "compressive stress in the post is  7789.0 psi\n",
-        "compressive strain in the post is 7.500000e-04\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.2, page no. 10"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "formula for maximum stress & calculating maximum stress\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "W = 1500                    # weight (Newton)\n",
-      "d = 0.008                   #diameter(meter) \n",
-      "g = 77000                   # Weight density of steel\n",
-      "L = 40                      # Length of bar (m)\n",
-      "\n",
-      "#calculation\n",
-      "\n",
-      "A = (math.pi/4)*(d**2)      # Area\n",
-      "s_max = (1500/A) + (g*L)    # maximum stress\n",
-      "\n",
-      "#result\n",
-      "print \"Therefore the maximum stress in the rod is \", round(s_max,1), \"Pa\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Therefore the maximum stress in the rod is  32921551.8 Pa\n"
-       ]
-      }
-     ],
-     "prompt_number": 16
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.3. page no. 26"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculating change in lenght of pipe, strain in pipe, increase in diameter & increase in wall thickness\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "d1 = 4.5                            # diameter in inch\n",
-      "d2 = 6                              # diameter in inch\n",
-      "A = (math.pi/4)*((d2**2)-(d1**2))   # Area\n",
-      "P = 140                             # pressure in K\n",
-      "s = -P/A                            # stress (compression)\n",
-      "E = 30000                           # young's modulus in Ksi\n",
-      "e = s/E                             # strain\n",
-      "\n",
-      "#calculation\n",
-      "\n",
-      "# Part (a)\n",
-      "my_del = e*4*12                        # del = e*L \n",
-      "print \"Change in length of the pipe is\", round(my_del,3), \"inch\"\n",
-      "\n",
-      "# Part (b)\n",
-      "v = 0.30                            # Poissio's ratio\n",
-      "e_ = -(v*e)\n",
-      "print \"Lateral strain in the pipe is %e\" %e_\n",
-      "\n",
-      "# Part (c)\n",
-      "del_d2 = e_*d2 \n",
-      "del_d1 = e_*d1\n",
-      "print \"Increase in the inner diameter is \", round(del_d1,6), \"inch\"\n",
-      "\n",
-      "# Part (d)\n",
-      "t = 0.75\n",
-      "del_t = e_*t\n",
-      "print \"Increase in the wall thicness is %f\" %del_t, \"inch\"\n",
-      "del_t1 = (del_d2-del_d1)/2 \n",
-      "print \"del_t1 = del_t\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Change in length of the pipe is -0.018 inch\n",
-        "Lateral strain in the pipe is 1.131768e-04\n",
-        "Increase in the inner diameter is  0.000509 inch\n",
-        "Increase in the wall thicness is 0.000085 inch\n",
-        "del_t1 = del_t\n"
-       ]
-      }
-     ],
-     "prompt_number": 7
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.4, page no. 35"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculate average shear stress and compressive stress\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "d = 0.02                            # diameter in m\n",
-      "t = 0.008                           # thickness in m\n",
-      "A = math.pi*d*t                     # shear area\n",
-      "P = 110000                          # prassure in Newton\n",
-      "\n",
-      "#calculation\n",
-      "A1 = (math.pi/4)*(d**2)             # Punch area\n",
-      "t_aver = P/A                        # Average shear stress \n",
-      "\n",
-      "\n",
-      "print \"Average shear stress in the plate is \", t_aver, \"Pa\"\n",
-      "s_c = P/A1  # compressive stress\n",
-      "print \"Average compressive stress in the plate is \", s_c, \"Pa\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Average shear stress in the plate is  218838046.751 Pa\n",
-        "Average compressive stress in the plate is  350140874.802 Pa\n"
-       ]
-      }
-     ],
-     "prompt_number": 37
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Eample 1.5, page no. 36"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculate bearing stress, shear stress in pin,\n",
-      "bearing stress between pin and gussets,\n",
-      "shear stress in anchor bolts\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "\n",
-      "P = 12.0                              # Pressure in K\n",
-      "t = 0.375                           # thickness of wall in inch\n",
-      "theta = 40.0                          # angle in degree\n",
-      "d_pin = 0.75                        # diameter of pin in inch\n",
-      "t_G = 0.625                         # thickness of gusset in inch\n",
-      "t_B = 0.375                         #thickness of base plate in inch\n",
-      "d_b = 0.50                          # diameter of bolt in inch\n",
-      "\n",
-      "#calculation\n",
-      "\n",
-      "#Part (a)\n",
-      "s_b1 = P/(2*t*d_pin)                  # bearing stress\n",
-      "print \"Bearing stress between strut and pin\", round(s_b1,1), \"ksi\"\n",
-      "\n",
-      "#Part (b)\n",
-      "t_pin = (4*P)/(2*math.pi*(d_pin**2))  # average shear stress in the \n",
-      "print \"Shear stress in pin is \", round(t_pin,1), \"ksi\"\n",
-      "\n",
-      "# Part (c)\n",
-      "s_b2 = P/(2*t_G*d_pin)                # bearing stress between pin and gusset\n",
-      "print \"Bearing stress between pin and gussets is\", s_b2, \"ksi\"\n",
-      "\n",
-      "# Part (d)\n",
-      "s_b3 = (P*math.cos(math.radians(40))/(4*t_B*d_b)) # bearing stress between anchor bolt and base plate\n",
-      "print \"Bearing stress between anchor bolts & base plate\", round(s_b3,1), \"ksi\"\n",
-      "\n",
-      "# Part (e)\n",
-      "t_bolt = (4*math.cos(math.radians(40))*P)/(4*math.pi*(d_b**2))  # shear stress in anchor bolt\n",
-      "print \"Shear stress in anchor bolts is\", round(t_bolt,1), \"ksi\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Bearing stress between strut and pin 21.3 ksi\n",
-        "Shear stress in pin is  13.6 ksi\n",
-        "Bearing stress between pin and gussets is 12.8 ksi\n",
-        "Bearing stress between anchor bolts & base plate 12.3 ksi\n",
-        "Shear stress in anchor bolts is 11.7 ksi\n"
-       ]
-      }
-     ],
-     "prompt_number": 39
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.7, page no. 42"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "determine stress at various parts\n",
-      "\"\"\"\n",
-      "\n",
-      "import math\n",
-      "\n",
-      "#initialisation\n",
-      "b1 = 1.5                            # width of recmath.tangular crosssection in inch\n",
-      "t = 0.5                             # thickness of recmath.tangular crosssection in inch\n",
-      "b2 = 3.0                            # width  of enlarged recmath.tangular crosssection in inch\n",
-      "d = 1.0                             # diameter in inch\n",
-      "\n",
-      "#calculation\n",
-      "\n",
-      "# Part (a)\n",
-      "s_1 = 16000 # maximum allowable tensile stress in Psi\n",
-      "P_1 = s_1*t*b1 \n",
-      "print \"The allowable load  P1 is\", P_1, \"lb\"\n",
-      "\n",
-      "# Part (b)\n",
-      "s_2 = 11000 # maximum allowable tensile stress in Psi\n",
-      "P_2 = s_2*t*(b2-d) \n",
-      "print \"allowable load P2 at this section is\", P_2, \"lb\"\n",
-      "\n",
-      "#Part (c)\n",
-      "s_3 = 26000 # maximum allowable tensile stress in Psi\n",
-      "P_3 = s_3*t*d \n",
-      "print \"The allowable load based upon bearing between the hanger and the bolt is\", P_3, \"lb\"\n",
-      "\n",
-      "# Part (d)\n",
-      "s_4 = 6500 # maximum allowable tensile stress in Psi\n",
-      "P_4 = (math.pi/4)*(d**2)*2*s_4 \n",
-      "print \"the allowable load  P4 based upon shear in the bolt is\", round(P_4), \"lb\"\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The allowable load  P1 is 12000.0 lb\n",
-        "allowable load P2 at this section is 11000.0 lb\n",
-        "The allowable load based upon bearing between the hanger and the bolt is 13000.0 lb\n",
-        "the allowable load  P4 based upon shear in the bolt is 10210.0 lb\n"
-       ]
-      }
-     ],
-     "prompt_number": 42
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.8, page no. 46"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculating the cross sectional area \n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "R_ah = (2700*0.8 + 2700*2.6)/2                  # Horizontal component at A in N\n",
-      "R_ch = R_ah                                     # Horizontal component at C in N\n",
-      "R_cv = (2700*2.2 + 2700*0.4)/3                  # vertical component at C in N\n",
-      "R_av = 2700 + 2700 - R_cv                       # vertical component at A in N\n",
-      "R_a = math.sqrt((R_ah**2)+(R_av**2))\n",
-      "R_c = math.sqrt((R_ch**2)+(R_cv**2))\n",
-      "Fab = R_a                                       # Tensile force in bar AB\n",
-      "Vc = R_c                                        # Shear force acting on the pin at C\n",
-      "s_allow = 125000000                             # allowable stress in tension \n",
-      "t_allow = 45000000                              # allowable stress in shear\n",
-      "\n",
-      "#calculation\n",
-      "Aab = Fab / s_allow                             # required area of bar \n",
-      "Apin = Vc / (2*t_allow)                         # required area of pin\n",
-      "\n",
-      "\n",
-      "print \"Required area of bar is %f\" %Apin, \"m^2\"\n",
-      "d = math.sqrt((4*Apin)/math.pi)                 # diameter in meter\n",
-      "print \"Required diameter of pin is %f\" %d, \"m\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Required area of bar is 0.000057 m^2\n",
-        "Required diameter of pin is 0.008537 m\n"
-       ]
-      }
-     ],
-     "prompt_number": 9
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [],
-     "language": "python",
-     "metadata": {},
-     "outputs": []
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Test/chapter1_1.ipynb b/Test/chapter1_1.ipynb
deleted file mode 100755
index cf45a409..00000000
--- a/Test/chapter1_1.ipynb
+++ /dev/null
@@ -1,423 +0,0 @@
-{
- "metadata": {
-  "name": ""
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 1: Tension Comprssion and Shear"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.1, page no. 9"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "Find compressive stress and strain in the post\n",
-      "\"\"\"\n",
-      "\n",
-      "import math\n",
-      "\n",
-      "#initialisation\n",
-      "\n",
-      "d_1 = 4                 # inner diameter (inch)\n",
-      "d_2 = 4.5               #outer diameter (inch)\n",
-      "P = 26000               # pressure in pound\n",
-      "L = 16                  # Length of cylinder (inch)\n",
-      "my_del = 0.012             # shortening of post (inch)\n",
-      "\n",
-      "#calculation\n",
-      "A = (math.pi/4)*((d_2**2)-(d_1**2))     #Area (inch^2)\n",
-      "s = P/A                                 # stress\n",
-      "\n",
-      "print \"compressive stress in the post is \", round(s), \"psi\"\n",
-      "\n",
-      "e = my_del/L                            # strain\n",
-      "\n",
-      "print \"compressive strain in the post is %e\" %e"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "compressive stress in the post is  7789.0 psi\n",
-        "compressive strain in the post is 7.500000e-04\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.2, page no. 10"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "formula for maximum stress & calculating maximum stress\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "W = 1500                    # weight (Newton)\n",
-      "d = 0.008                   #diameter(meter) \n",
-      "g = 77000                   # Weight density of steel\n",
-      "L = 40                      # Length of bar (m)\n",
-      "\n",
-      "#calculation\n",
-      "\n",
-      "A = (math.pi/4)*(d**2)      # Area\n",
-      "s_max = (1500/A) + (g*L)    # maximum stress\n",
-      "\n",
-      "#result\n",
-      "print \"Therefore the maximum stress in the rod is \", round(s_max,1), \"Pa\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Therefore the maximum stress in the rod is  32921551.8 Pa\n"
-       ]
-      }
-     ],
-     "prompt_number": 16
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.3. page no. 26"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculating change in lenght of pipe, strain in pipe, increase in diameter & increase in wall thickness\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "d1 = 4.5                            # diameter in inch\n",
-      "d2 = 6                              # diameter in inch\n",
-      "A = (math.pi/4)*((d2**2)-(d1**2))   # Area\n",
-      "P = 140                             # pressure in K\n",
-      "s = -P/A                            # stress (compression)\n",
-      "E = 30000                           # young's modulus in Ksi\n",
-      "e = s/E                             # strain\n",
-      "\n",
-      "#calculation\n",
-      "\n",
-      "# Part (a)\n",
-      "my_del = e*4*12                        # del = e*L \n",
-      "print \"Change in length of the pipe is\", round(my_del,3), \"inch\"\n",
-      "\n",
-      "# Part (b)\n",
-      "v = 0.30                            # Poissio's ratio\n",
-      "e_ = -(v*e)\n",
-      "print \"Lateral strain in the pipe is %e\" %e_\n",
-      "\n",
-      "# Part (c)\n",
-      "del_d2 = e_*d2 \n",
-      "del_d1 = e_*d1\n",
-      "print \"Increase in the inner diameter is \", round(del_d1,6), \"inch\"\n",
-      "\n",
-      "# Part (d)\n",
-      "t = 0.75\n",
-      "del_t = e_*t\n",
-      "print \"Increase in the wall thicness is %f\" %del_t, \"inch\"\n",
-      "del_t1 = (del_d2-del_d1)/2 \n",
-      "print \"del_t1 = del_t\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Change in length of the pipe is -0.018 inch\n",
-        "Lateral strain in the pipe is 1.131768e-04\n",
-        "Increase in the inner diameter is  0.000509 inch\n",
-        "Increase in the wall thicness is 0.000085 inch\n",
-        "del_t1 = del_t\n"
-       ]
-      }
-     ],
-     "prompt_number": 7
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.4, page no. 35"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculate average shear stress and compressive stress\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "d = 0.02                            # diameter in m\n",
-      "t = 0.008                           # thickness in m\n",
-      "A = math.pi*d*t                     # shear area\n",
-      "P = 110000                          # prassure in Newton\n",
-      "\n",
-      "#calculation\n",
-      "A1 = (math.pi/4)*(d**2)             # Punch area\n",
-      "t_aver = P/A                        # Average shear stress \n",
-      "\n",
-      "\n",
-      "print \"Average shear stress in the plate is \", t_aver, \"Pa\"\n",
-      "s_c = P/A1  # compressive stress\n",
-      "print \"Average compressive stress in the plate is \", s_c, \"Pa\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Average shear stress in the plate is  218838046.751 Pa\n",
-        "Average compressive stress in the plate is  350140874.802 Pa\n"
-       ]
-      }
-     ],
-     "prompt_number": 37
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Eample 1.5, page no. 36"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculate bearing stress, shear stress in pin,\n",
-      "bearing stress between pin and gussets,\n",
-      "shear stress in anchor bolts\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "\n",
-      "P = 12.0                              # Pressure in K\n",
-      "t = 0.375                           # thickness of wall in inch\n",
-      "theta = 40.0                          # angle in degree\n",
-      "d_pin = 0.75                        # diameter of pin in inch\n",
-      "t_G = 0.625                         # thickness of gusset in inch\n",
-      "t_B = 0.375                         #thickness of base plate in inch\n",
-      "d_b = 0.50                          # diameter of bolt in inch\n",
-      "\n",
-      "#calculation\n",
-      "\n",
-      "#Part (a)\n",
-      "s_b1 = P/(2*t*d_pin)                  # bearing stress\n",
-      "print \"Bearing stress between strut and pin\", round(s_b1,1), \"ksi\"\n",
-      "\n",
-      "#Part (b)\n",
-      "t_pin = (4*P)/(2*math.pi*(d_pin**2))  # average shear stress in the \n",
-      "print \"Shear stress in pin is \", round(t_pin,1), \"ksi\"\n",
-      "\n",
-      "# Part (c)\n",
-      "s_b2 = P/(2*t_G*d_pin)                # bearing stress between pin and gusset\n",
-      "print \"Bearing stress between pin and gussets is\", s_b2, \"ksi\"\n",
-      "\n",
-      "# Part (d)\n",
-      "s_b3 = (P*math.cos(math.radians(40))/(4*t_B*d_b)) # bearing stress between anchor bolt and base plate\n",
-      "print \"Bearing stress between anchor bolts & base plate\", round(s_b3,1), \"ksi\"\n",
-      "\n",
-      "# Part (e)\n",
-      "t_bolt = (4*math.cos(math.radians(40))*P)/(4*math.pi*(d_b**2))  # shear stress in anchor bolt\n",
-      "print \"Shear stress in anchor bolts is\", round(t_bolt,1), \"ksi\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Bearing stress between strut and pin 21.3 ksi\n",
-        "Shear stress in pin is  13.6 ksi\n",
-        "Bearing stress between pin and gussets is 12.8 ksi\n",
-        "Bearing stress between anchor bolts & base plate 12.3 ksi\n",
-        "Shear stress in anchor bolts is 11.7 ksi\n"
-       ]
-      }
-     ],
-     "prompt_number": 39
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.7, page no. 42"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "determine stress at various parts\n",
-      "\"\"\"\n",
-      "\n",
-      "import math\n",
-      "\n",
-      "#initialisation\n",
-      "b1 = 1.5                            # width of recmath.tangular crosssection in inch\n",
-      "t = 0.5                             # thickness of recmath.tangular crosssection in inch\n",
-      "b2 = 3.0                            # width  of enlarged recmath.tangular crosssection in inch\n",
-      "d = 1.0                             # diameter in inch\n",
-      "\n",
-      "#calculation\n",
-      "\n",
-      "# Part (a)\n",
-      "s_1 = 16000 # maximum allowable tensile stress in Psi\n",
-      "P_1 = s_1*t*b1 \n",
-      "print \"The allowable load  P1 is\", P_1, \"lb\"\n",
-      "\n",
-      "# Part (b)\n",
-      "s_2 = 11000 # maximum allowable tensile stress in Psi\n",
-      "P_2 = s_2*t*(b2-d) \n",
-      "print \"allowable load P2 at this section is\", P_2, \"lb\"\n",
-      "\n",
-      "#Part (c)\n",
-      "s_3 = 26000 # maximum allowable tensile stress in Psi\n",
-      "P_3 = s_3*t*d \n",
-      "print \"The allowable load based upon bearing between the hanger and the bolt is\", P_3, \"lb\"\n",
-      "\n",
-      "# Part (d)\n",
-      "s_4 = 6500 # maximum allowable tensile stress in Psi\n",
-      "P_4 = (math.pi/4)*(d**2)*2*s_4 \n",
-      "print \"the allowable load  P4 based upon shear in the bolt is\", round(P_4), \"lb\"\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The allowable load  P1 is 12000.0 lb\n",
-        "allowable load P2 at this section is 11000.0 lb\n",
-        "The allowable load based upon bearing between the hanger and the bolt is 13000.0 lb\n",
-        "the allowable load  P4 based upon shear in the bolt is 10210.0 lb\n"
-       ]
-      }
-     ],
-     "prompt_number": 42
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.8, page no. 46"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculating the cross sectional area \n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "R_ah = (2700*0.8 + 2700*2.6)/2                  # Horizontal component at A in N\n",
-      "R_ch = R_ah                                     # Horizontal component at C in N\n",
-      "R_cv = (2700*2.2 + 2700*0.4)/3                  # vertical component at C in N\n",
-      "R_av = 2700 + 2700 - R_cv                       # vertical component at A in N\n",
-      "R_a = math.sqrt((R_ah**2)+(R_av**2))\n",
-      "R_c = math.sqrt((R_ch**2)+(R_cv**2))\n",
-      "Fab = R_a                                       # Tensile force in bar AB\n",
-      "Vc = R_c                                        # Shear force acting on the pin at C\n",
-      "s_allow = 125000000                             # allowable stress in tension \n",
-      "t_allow = 45000000                              # allowable stress in shear\n",
-      "\n",
-      "#calculation\n",
-      "Aab = Fab / s_allow                             # required area of bar \n",
-      "Apin = Vc / (2*t_allow)                         # required area of pin\n",
-      "\n",
-      "\n",
-      "print \"Required area of bar is %f\" %Apin, \"m^2\"\n",
-      "d = math.sqrt((4*Apin)/math.pi)                 # diameter in meter\n",
-      "print \"Required diameter of pin is %f\" %d, \"m\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Required area of bar is 0.000057 m^2\n",
-        "Required diameter of pin is 0.008537 m\n"
-       ]
-      }
-     ],
-     "prompt_number": 9
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [],
-     "language": "python",
-     "metadata": {},
-     "outputs": []
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Test/chapter1_2.ipynb b/Test/chapter1_2.ipynb
deleted file mode 100755
index cf45a409..00000000
--- a/Test/chapter1_2.ipynb
+++ /dev/null
@@ -1,423 +0,0 @@
-{
- "metadata": {
-  "name": ""
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 1: Tension Comprssion and Shear"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.1, page no. 9"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "Find compressive stress and strain in the post\n",
-      "\"\"\"\n",
-      "\n",
-      "import math\n",
-      "\n",
-      "#initialisation\n",
-      "\n",
-      "d_1 = 4                 # inner diameter (inch)\n",
-      "d_2 = 4.5               #outer diameter (inch)\n",
-      "P = 26000               # pressure in pound\n",
-      "L = 16                  # Length of cylinder (inch)\n",
-      "my_del = 0.012             # shortening of post (inch)\n",
-      "\n",
-      "#calculation\n",
-      "A = (math.pi/4)*((d_2**2)-(d_1**2))     #Area (inch^2)\n",
-      "s = P/A                                 # stress\n",
-      "\n",
-      "print \"compressive stress in the post is \", round(s), \"psi\"\n",
-      "\n",
-      "e = my_del/L                            # strain\n",
-      "\n",
-      "print \"compressive strain in the post is %e\" %e"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "compressive stress in the post is  7789.0 psi\n",
-        "compressive strain in the post is 7.500000e-04\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.2, page no. 10"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "formula for maximum stress & calculating maximum stress\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "W = 1500                    # weight (Newton)\n",
-      "d = 0.008                   #diameter(meter) \n",
-      "g = 77000                   # Weight density of steel\n",
-      "L = 40                      # Length of bar (m)\n",
-      "\n",
-      "#calculation\n",
-      "\n",
-      "A = (math.pi/4)*(d**2)      # Area\n",
-      "s_max = (1500/A) + (g*L)    # maximum stress\n",
-      "\n",
-      "#result\n",
-      "print \"Therefore the maximum stress in the rod is \", round(s_max,1), \"Pa\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Therefore the maximum stress in the rod is  32921551.8 Pa\n"
-       ]
-      }
-     ],
-     "prompt_number": 16
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.3. page no. 26"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculating change in lenght of pipe, strain in pipe, increase in diameter & increase in wall thickness\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "d1 = 4.5                            # diameter in inch\n",
-      "d2 = 6                              # diameter in inch\n",
-      "A = (math.pi/4)*((d2**2)-(d1**2))   # Area\n",
-      "P = 140                             # pressure in K\n",
-      "s = -P/A                            # stress (compression)\n",
-      "E = 30000                           # young's modulus in Ksi\n",
-      "e = s/E                             # strain\n",
-      "\n",
-      "#calculation\n",
-      "\n",
-      "# Part (a)\n",
-      "my_del = e*4*12                        # del = e*L \n",
-      "print \"Change in length of the pipe is\", round(my_del,3), \"inch\"\n",
-      "\n",
-      "# Part (b)\n",
-      "v = 0.30                            # Poissio's ratio\n",
-      "e_ = -(v*e)\n",
-      "print \"Lateral strain in the pipe is %e\" %e_\n",
-      "\n",
-      "# Part (c)\n",
-      "del_d2 = e_*d2 \n",
-      "del_d1 = e_*d1\n",
-      "print \"Increase in the inner diameter is \", round(del_d1,6), \"inch\"\n",
-      "\n",
-      "# Part (d)\n",
-      "t = 0.75\n",
-      "del_t = e_*t\n",
-      "print \"Increase in the wall thicness is %f\" %del_t, \"inch\"\n",
-      "del_t1 = (del_d2-del_d1)/2 \n",
-      "print \"del_t1 = del_t\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Change in length of the pipe is -0.018 inch\n",
-        "Lateral strain in the pipe is 1.131768e-04\n",
-        "Increase in the inner diameter is  0.000509 inch\n",
-        "Increase in the wall thicness is 0.000085 inch\n",
-        "del_t1 = del_t\n"
-       ]
-      }
-     ],
-     "prompt_number": 7
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.4, page no. 35"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculate average shear stress and compressive stress\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "d = 0.02                            # diameter in m\n",
-      "t = 0.008                           # thickness in m\n",
-      "A = math.pi*d*t                     # shear area\n",
-      "P = 110000                          # prassure in Newton\n",
-      "\n",
-      "#calculation\n",
-      "A1 = (math.pi/4)*(d**2)             # Punch area\n",
-      "t_aver = P/A                        # Average shear stress \n",
-      "\n",
-      "\n",
-      "print \"Average shear stress in the plate is \", t_aver, \"Pa\"\n",
-      "s_c = P/A1  # compressive stress\n",
-      "print \"Average compressive stress in the plate is \", s_c, \"Pa\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Average shear stress in the plate is  218838046.751 Pa\n",
-        "Average compressive stress in the plate is  350140874.802 Pa\n"
-       ]
-      }
-     ],
-     "prompt_number": 37
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Eample 1.5, page no. 36"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculate bearing stress, shear stress in pin,\n",
-      "bearing stress between pin and gussets,\n",
-      "shear stress in anchor bolts\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "\n",
-      "P = 12.0                              # Pressure in K\n",
-      "t = 0.375                           # thickness of wall in inch\n",
-      "theta = 40.0                          # angle in degree\n",
-      "d_pin = 0.75                        # diameter of pin in inch\n",
-      "t_G = 0.625                         # thickness of gusset in inch\n",
-      "t_B = 0.375                         #thickness of base plate in inch\n",
-      "d_b = 0.50                          # diameter of bolt in inch\n",
-      "\n",
-      "#calculation\n",
-      "\n",
-      "#Part (a)\n",
-      "s_b1 = P/(2*t*d_pin)                  # bearing stress\n",
-      "print \"Bearing stress between strut and pin\", round(s_b1,1), \"ksi\"\n",
-      "\n",
-      "#Part (b)\n",
-      "t_pin = (4*P)/(2*math.pi*(d_pin**2))  # average shear stress in the \n",
-      "print \"Shear stress in pin is \", round(t_pin,1), \"ksi\"\n",
-      "\n",
-      "# Part (c)\n",
-      "s_b2 = P/(2*t_G*d_pin)                # bearing stress between pin and gusset\n",
-      "print \"Bearing stress between pin and gussets is\", s_b2, \"ksi\"\n",
-      "\n",
-      "# Part (d)\n",
-      "s_b3 = (P*math.cos(math.radians(40))/(4*t_B*d_b)) # bearing stress between anchor bolt and base plate\n",
-      "print \"Bearing stress between anchor bolts & base plate\", round(s_b3,1), \"ksi\"\n",
-      "\n",
-      "# Part (e)\n",
-      "t_bolt = (4*math.cos(math.radians(40))*P)/(4*math.pi*(d_b**2))  # shear stress in anchor bolt\n",
-      "print \"Shear stress in anchor bolts is\", round(t_bolt,1), \"ksi\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Bearing stress between strut and pin 21.3 ksi\n",
-        "Shear stress in pin is  13.6 ksi\n",
-        "Bearing stress between pin and gussets is 12.8 ksi\n",
-        "Bearing stress between anchor bolts & base plate 12.3 ksi\n",
-        "Shear stress in anchor bolts is 11.7 ksi\n"
-       ]
-      }
-     ],
-     "prompt_number": 39
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.7, page no. 42"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "determine stress at various parts\n",
-      "\"\"\"\n",
-      "\n",
-      "import math\n",
-      "\n",
-      "#initialisation\n",
-      "b1 = 1.5                            # width of recmath.tangular crosssection in inch\n",
-      "t = 0.5                             # thickness of recmath.tangular crosssection in inch\n",
-      "b2 = 3.0                            # width  of enlarged recmath.tangular crosssection in inch\n",
-      "d = 1.0                             # diameter in inch\n",
-      "\n",
-      "#calculation\n",
-      "\n",
-      "# Part (a)\n",
-      "s_1 = 16000 # maximum allowable tensile stress in Psi\n",
-      "P_1 = s_1*t*b1 \n",
-      "print \"The allowable load  P1 is\", P_1, \"lb\"\n",
-      "\n",
-      "# Part (b)\n",
-      "s_2 = 11000 # maximum allowable tensile stress in Psi\n",
-      "P_2 = s_2*t*(b2-d) \n",
-      "print \"allowable load P2 at this section is\", P_2, \"lb\"\n",
-      "\n",
-      "#Part (c)\n",
-      "s_3 = 26000 # maximum allowable tensile stress in Psi\n",
-      "P_3 = s_3*t*d \n",
-      "print \"The allowable load based upon bearing between the hanger and the bolt is\", P_3, \"lb\"\n",
-      "\n",
-      "# Part (d)\n",
-      "s_4 = 6500 # maximum allowable tensile stress in Psi\n",
-      "P_4 = (math.pi/4)*(d**2)*2*s_4 \n",
-      "print \"the allowable load  P4 based upon shear in the bolt is\", round(P_4), \"lb\"\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The allowable load  P1 is 12000.0 lb\n",
-        "allowable load P2 at this section is 11000.0 lb\n",
-        "The allowable load based upon bearing between the hanger and the bolt is 13000.0 lb\n",
-        "the allowable load  P4 based upon shear in the bolt is 10210.0 lb\n"
-       ]
-      }
-     ],
-     "prompt_number": 42
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.8, page no. 46"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculating the cross sectional area \n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "R_ah = (2700*0.8 + 2700*2.6)/2                  # Horizontal component at A in N\n",
-      "R_ch = R_ah                                     # Horizontal component at C in N\n",
-      "R_cv = (2700*2.2 + 2700*0.4)/3                  # vertical component at C in N\n",
-      "R_av = 2700 + 2700 - R_cv                       # vertical component at A in N\n",
-      "R_a = math.sqrt((R_ah**2)+(R_av**2))\n",
-      "R_c = math.sqrt((R_ch**2)+(R_cv**2))\n",
-      "Fab = R_a                                       # Tensile force in bar AB\n",
-      "Vc = R_c                                        # Shear force acting on the pin at C\n",
-      "s_allow = 125000000                             # allowable stress in tension \n",
-      "t_allow = 45000000                              # allowable stress in shear\n",
-      "\n",
-      "#calculation\n",
-      "Aab = Fab / s_allow                             # required area of bar \n",
-      "Apin = Vc / (2*t_allow)                         # required area of pin\n",
-      "\n",
-      "\n",
-      "print \"Required area of bar is %f\" %Apin, \"m^2\"\n",
-      "d = math.sqrt((4*Apin)/math.pi)                 # diameter in meter\n",
-      "print \"Required diameter of pin is %f\" %d, \"m\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Required area of bar is 0.000057 m^2\n",
-        "Required diameter of pin is 0.008537 m\n"
-       ]
-      }
-     ],
-     "prompt_number": 9
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [],
-     "language": "python",
-     "metadata": {},
-     "outputs": []
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Test/chapter2.ipynb b/Test/chapter2.ipynb
deleted file mode 100755
index c4e1ad0f..00000000
--- a/Test/chapter2.ipynb
+++ /dev/null
@@ -1,501 +0,0 @@
-{
- "metadata": {
-  "name": ""
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 2: Axially Loaded Members"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.1, page no. 72"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculating the number of revolutions for the nut\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "\n",
-      "W = 2.0                       #lb\n",
-      "b = 10.5                   #inch\n",
-      "c = 6.4                    #inch\n",
-      "k = 4.2                    #inch\n",
-      "p = 1.0/16.0                   #inch\n",
-      "\n",
-      "#calculation\n",
-      "\n",
-      "n = (W*b)/(c*k*p)          #inch\n",
-      "\n",
-      "#result\n",
-      "\n",
-      "print \" No. of revolution required = \", n, \"revolutions\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " No. of revolution required =  12.5 revolutions\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.2, page no. 74"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "finding maximum allowable load\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "import numpy\n",
-      "\n",
-      "#initialisation\n",
-      "\n",
-      "Fce_ = 2.0                    #dummy variable\n",
-      "Fbd_ = 3.0                    #dummy variable    \n",
-      "Lbd = 480.0                   #mm\n",
-      "Lce = 600.0                  #mm\n",
-      "E = 205e6                   #205Gpa\n",
-      "Abd = 1020.0                  #mm\n",
-      "Ace = 520.0                   #mm\n",
-      "\n",
-      "#calculation\n",
-      "Dbd_ = (Fbd_*Lbd)/(E*Abd)   #dummy variable\n",
-      "Dce_ = (Fce_*Lce)/(E*Ace)   #dummy variable\n",
-      "Da = 1 #limiting value\n",
-      "P = ((((450+225)/225)*(Dbd_ + Dce_) - Dce_ )**(-1)) * Da  \n",
-      "Fce = 2*P # Real value in newton\n",
-      "Fbd = 3*P #real value in newton\n",
-      "Dbd = (Fbd*Lbd)/(E*Abd) #print lacement in mm\n",
-      "Dce = (Fce*Lce)/(E*Ace) # print lacement in mm\n",
-      "a = numpy.degrees(numpy.arctan(((Da+Dce)/675)))  #alpha in degree\n",
-      "\n",
-      "#result\n",
-      "print \"alpha = \", round(a,2), \"degree\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "alpha =  0.11 degree\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.3, page no. 80"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculation if vertical displacement\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "P1 = 2100.0                       #lb\n",
-      "P2 = 5600.0                       #lb\n",
-      "b = 25.0                          #inch\n",
-      "a = 28.0                          #inch\n",
-      "A1 = 0.25                       #inch^2\n",
-      "A2 = 0.15                       #inch^2\n",
-      "L1 = 20.0                         #inch\n",
-      "L2 = 34.8                       #inch\n",
-      "E = 29e6                        #29Gpa\n",
-      "\n",
-      "#Calculations\n",
-      "P3 = (P2*b)/a \n",
-      "Ra = P3-P1\n",
-      "N1 = -Ra \n",
-      "N2 = P1 \n",
-      "D = ((N1*L1)/(E*A1)) + ((N2*L2)/(E*A2))     #print lacement\n",
-      "\n",
-      "#Result\n",
-      "print  \"Downward print lacement is = \", D, \"inch\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Downward print lacement is =  0.0088 inch\n"
-       ]
-      }
-     ],
-     "prompt_number": 4
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.6, page no. 90"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "obtaing formula and calculating allowable load\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#Numerical calculation of allowable load\n",
-      "\n",
-      "d1 = 4.0                      #mm\n",
-      "d2 = 3.0                      #mm\n",
-      "A1 = (math.pi*(d1**2))/4    #area\n",
-      "A2 = (math.pi*(d2**2))/4    #area\n",
-      "L1 = 0.4                    #meter\n",
-      "L2 = 0.3                    #meter\n",
-      "E1 = 72e9                   #Gpa\n",
-      "E2 = 45e9                   #Gpa\n",
-      "f1 = L1/(E1*A1) * 1e6       # To cpmpensate for the mm**2\n",
-      "f2 = L2/(E2*A2) * 1e6 \n",
-      "s1 = 200e6                  #stress\n",
-      "s2 = 175e6                  #stress\n",
-      "\n",
-      "#Calculations\n",
-      "P1 = ( (s1*A1*(4*f1 + f2))/(3*f2) ) * 1e-6      # To cpmpensate for the mm**2\n",
-      "P2 = ( (s2*A2*(4*f1 + f2))/(6*f1) ) * 1e-6 \n",
-      "\n",
-      "#Result\n",
-      "print \"Newton Minimum allowable stress aomong the two P1 and P2 is smaller one, therefore MAS = \", P2"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Newton Minimum allowable stress aomong the two P1 and P2 is smaller one, therefore MAS =  1264.49104307\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.10, page no. 113"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculate stress acting on inclined section &\n",
-      "the complete state of stress\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "P = 90000.0                   #newton\n",
-      "A = 1200e-6                   # meter^2\n",
-      "s_x = -P/A                    #stress\n",
-      "t_1 = 25.0                    #for the stresses on ab and cd plane\n",
-      "\n",
-      "#Calculations\n",
-      "s_1 = s_x*(math.cos(math.radians(t_1))**2)\n",
-      "T_1 = -s_x*math.cos(math.radians(t_1))*math.sin(math.radians(t_1))\n",
-      "t_2 = -65.0                   #for the stresses on ad and bc plane\n",
-      "s_2 = s_x*(math.cos(math.radians(t_2))**2)\n",
-      "T_2 = -s_x*math.cos(math.radians(t_2))*math.sin(math.radians(t_2))\n",
-      "\n",
-      "#Result\n",
-      "print \"The normal and shear stresses on the plane ab and cd are\", round((T_1/1E+6),2), round((s_1/1E+6),2), \"MPa respecively\" \n",
-      "print \"respecively The normal and shear stresses on the plane ad and bc are\", round((T_2/1E+6),2), round((s_2/1E+6),2), \"MPa respecively\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The normal and shear stresses on the plane ab and cd are 28.73 -61.6 MPa respecively\n",
-        "respecively The normal and shear stresses on the plane ad and bc are -28.73 -13.4 MPa respecively\n"
-       ]
-      }
-     ],
-     "prompt_number": 4
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.11, page no. 114"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "Calculate the vertical displacement of the joint\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "# Value of s_x based on allowable stresses on glued joint\n",
-      "\n",
-      "#initialisation\n",
-      "s_t = -750.0                                  #psi\n",
-      "t = -50.0                                     #degree\n",
-      "T_t = -500.0                                  #psi\n",
-      "\n",
-      "sg_x_1 = s_t/(math.cos(math.radians(t))**2)\n",
-      "sg_x_2 = -T_t/(math.cos(math.radians(t))*math.sin(math.radians(t)))\n",
-      "\n",
-      "# Value of s_x based on allowable stresses on plastic\n",
-      "\n",
-      "sp_x_1 = -1100.0                              #psi\n",
-      "T_t_p = 600.0                                  #psi\n",
-      "t_p = 45.0                                    #degree\n",
-      "sp_x_2 = -T_t_p/(math.cos(math.radians(t_p))*math.sin(math.radians(t_p)))\n",
-      "\n",
-      "# Minimum width of bar\n",
-      "\n",
-      "P = 8000.0                                    #lb\n",
-      "A = P/sg_x_2\n",
-      "b_min = math.sqrt(abs(A))                        #inch\n",
-      "print \"The minimum width of the bar is\", round(b_min,2), \"inch\"\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The minimum width of the bar is 2.81 inch\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.15, page no. 126"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "Comparison of energy-absorbing capacity with different type of bolts\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "#Bolt with reduced shank diameter\n",
-      "\n",
-      "#initialisation\n",
-      "g = 1.50                     # inch\n",
-      "d = 0.5                      #inch\n",
-      "t = 0.25                     #inch\n",
-      "d_r = 0.406                  #inch\n",
-      "L = 13.5                     #inch\n",
-      "\n",
-      "#calculation\n",
-      "ratio = ((g*(d**2))/(((g-t)*(d_r**2))+(t*(d**2))))              #U2/U1\n",
-      "\n",
-      "print \"The energy absorbing capacity of the bolts with reduced shank diameter\", round(ratio,2)\n",
-      "ratio_1 = ( (((L-t)*(d_r**2))+(t*(d**2))) / ((2*(g-t)*(d_r**2))+2*(t*(d**2))) )         #U3/2U1\n",
-      "print \"The energy absorbing capacity of the long bolts\", round(ratio_1,2)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The energy absorbing capacity of the bolts with reduced shank diameter 1.4\n",
-        "The energy absorbing capacity of the long bolts 4.18\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "    Example 2.16, page no. 133"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "Determine the maximum elongation and tensile stress\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "# Maximum elongation\n",
-      "M = 20                      #kg\n",
-      "g = 9.81                    #m/s^2\n",
-      "L = 2                       #meter\n",
-      "E = 210e9                   #210Gpa\n",
-      "h = 0.15                    #meter\n",
-      "diameter = 0.015            #milimeter\n",
-      "\n",
-      "#Calculations & Result\n",
-      "A = (math.pi/4)*(diameter**2)               #area\n",
-      "D_st = ((M*g*L)/(E*A)) \n",
-      "D_max = D_st*(1+(1+(2*h/D_st))**0.5) \n",
-      "D_max_1 = math.sqrt(2*h*D_st)                # another approach to find D_max\n",
-      "i = D_max / D_st                             # Impact factor\n",
-      "print \"Maximum elongation is\",round((D_max/1E-3),2), \"mm\"  # Maximum tensile stress\n",
-      "s_max = (E*D_max)/L                          #Maximum tensile stress\n",
-      "s_st = (M*g)/A                               #static stress\n",
-      "i_1 = s_max / s_st                           #Impact factor \n",
-      "print \"Maximum tensile stress is \", round((s_max/1E+6),2), \"MPa\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum elongation is 1.79 mm\n",
-        "Maximum tensile stress is  188.13 MPa\n"
-       ]
-      }
-     ],
-     "prompt_number": 7
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.18, page no. 148"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "determine displacement at the lower end of bar in various conditions\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "\n",
-      "#initialisation\n",
-      "P1 = 108000.0                 #Newton\n",
-      "P2 = 27000.0                  #Newton\n",
-      "L = 2.2                     #meter\n",
-      "A = 480.0                     #mm^2\n",
-      "\n",
-      "\n",
-      "#calculations\n",
-      "\n",
-      "# Displacement due to load P1 acting alone\n",
-      "s = (P1/A)                      #stress in MPa\n",
-      "e = (s/70000) + (1/628.2)*((s/260)**10)         #strain\n",
-      "D_b = e*L*1e3                                   #elongation in mm\n",
-      "print \"elongation when only P1 load acting is = \", round(D_b,2), \" mm\"\n",
-      "\n",
-      "# Displacement due to load P2 acting alone\n",
-      "s_1 = (P2/A) #stress in MPa\n",
-      "e_1 = (s_1/70000) + (1/628.2)*((s_1/260)**10) #strain\n",
-      "D_b_1 = e_1*(L/2)*1e3 #elongation in mm (no elongation in lower half)\n",
-      "print \"elongation when only P2 load acting is = \", round(D_b_1,2), \" mm\"\n",
-      "\n",
-      "# Displacement due to both load acting simonmath.taneously\n",
-      "#upper half\n",
-      "s_2 = (P1/A) #stress in MPa\n",
-      "e_2 = (s_2/70000) + (1/628.2)*((s_2/260)**10) #strain\n",
-      "\n",
-      "#lower half\n",
-      "s_3 = (P1+P2)/A #stress in MPa\n",
-      "e_3 = (s_3/70000) + (1/628.2)*((s_3/260)**10) #strain\n",
-      "D_b_2 = ((e_2*L)/2 + (e_3*L)/2) * 1e3 # elongation in mm\n",
-      "print \"elongation when P1 and P2 both loads are acting is = \", round(D_b_2,2), \" mm\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "elongation when only P1 load acting is =  7.9  mm\n",
-        "elongation when only P2 load acting is =  0.88  mm\n",
-        "elongation when P1 and P2 both loads are acting is =  12.21  mm\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Test/chapter2_1.ipynb b/Test/chapter2_1.ipynb
deleted file mode 100755
index c4e1ad0f..00000000
--- a/Test/chapter2_1.ipynb
+++ /dev/null
@@ -1,501 +0,0 @@
-{
- "metadata": {
-  "name": ""
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 2: Axially Loaded Members"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.1, page no. 72"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculating the number of revolutions for the nut\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "\n",
-      "W = 2.0                       #lb\n",
-      "b = 10.5                   #inch\n",
-      "c = 6.4                    #inch\n",
-      "k = 4.2                    #inch\n",
-      "p = 1.0/16.0                   #inch\n",
-      "\n",
-      "#calculation\n",
-      "\n",
-      "n = (W*b)/(c*k*p)          #inch\n",
-      "\n",
-      "#result\n",
-      "\n",
-      "print \" No. of revolution required = \", n, \"revolutions\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " No. of revolution required =  12.5 revolutions\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.2, page no. 74"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "finding maximum allowable load\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "import numpy\n",
-      "\n",
-      "#initialisation\n",
-      "\n",
-      "Fce_ = 2.0                    #dummy variable\n",
-      "Fbd_ = 3.0                    #dummy variable    \n",
-      "Lbd = 480.0                   #mm\n",
-      "Lce = 600.0                  #mm\n",
-      "E = 205e6                   #205Gpa\n",
-      "Abd = 1020.0                  #mm\n",
-      "Ace = 520.0                   #mm\n",
-      "\n",
-      "#calculation\n",
-      "Dbd_ = (Fbd_*Lbd)/(E*Abd)   #dummy variable\n",
-      "Dce_ = (Fce_*Lce)/(E*Ace)   #dummy variable\n",
-      "Da = 1 #limiting value\n",
-      "P = ((((450+225)/225)*(Dbd_ + Dce_) - Dce_ )**(-1)) * Da  \n",
-      "Fce = 2*P # Real value in newton\n",
-      "Fbd = 3*P #real value in newton\n",
-      "Dbd = (Fbd*Lbd)/(E*Abd) #print lacement in mm\n",
-      "Dce = (Fce*Lce)/(E*Ace) # print lacement in mm\n",
-      "a = numpy.degrees(numpy.arctan(((Da+Dce)/675)))  #alpha in degree\n",
-      "\n",
-      "#result\n",
-      "print \"alpha = \", round(a,2), \"degree\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "alpha =  0.11 degree\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.3, page no. 80"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculation if vertical displacement\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "P1 = 2100.0                       #lb\n",
-      "P2 = 5600.0                       #lb\n",
-      "b = 25.0                          #inch\n",
-      "a = 28.0                          #inch\n",
-      "A1 = 0.25                       #inch^2\n",
-      "A2 = 0.15                       #inch^2\n",
-      "L1 = 20.0                         #inch\n",
-      "L2 = 34.8                       #inch\n",
-      "E = 29e6                        #29Gpa\n",
-      "\n",
-      "#Calculations\n",
-      "P3 = (P2*b)/a \n",
-      "Ra = P3-P1\n",
-      "N1 = -Ra \n",
-      "N2 = P1 \n",
-      "D = ((N1*L1)/(E*A1)) + ((N2*L2)/(E*A2))     #print lacement\n",
-      "\n",
-      "#Result\n",
-      "print  \"Downward print lacement is = \", D, \"inch\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Downward print lacement is =  0.0088 inch\n"
-       ]
-      }
-     ],
-     "prompt_number": 4
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.6, page no. 90"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "obtaing formula and calculating allowable load\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#Numerical calculation of allowable load\n",
-      "\n",
-      "d1 = 4.0                      #mm\n",
-      "d2 = 3.0                      #mm\n",
-      "A1 = (math.pi*(d1**2))/4    #area\n",
-      "A2 = (math.pi*(d2**2))/4    #area\n",
-      "L1 = 0.4                    #meter\n",
-      "L2 = 0.3                    #meter\n",
-      "E1 = 72e9                   #Gpa\n",
-      "E2 = 45e9                   #Gpa\n",
-      "f1 = L1/(E1*A1) * 1e6       # To cpmpensate for the mm**2\n",
-      "f2 = L2/(E2*A2) * 1e6 \n",
-      "s1 = 200e6                  #stress\n",
-      "s2 = 175e6                  #stress\n",
-      "\n",
-      "#Calculations\n",
-      "P1 = ( (s1*A1*(4*f1 + f2))/(3*f2) ) * 1e-6      # To cpmpensate for the mm**2\n",
-      "P2 = ( (s2*A2*(4*f1 + f2))/(6*f1) ) * 1e-6 \n",
-      "\n",
-      "#Result\n",
-      "print \"Newton Minimum allowable stress aomong the two P1 and P2 is smaller one, therefore MAS = \", P2"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Newton Minimum allowable stress aomong the two P1 and P2 is smaller one, therefore MAS =  1264.49104307\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.10, page no. 113"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculate stress acting on inclined section &\n",
-      "the complete state of stress\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "P = 90000.0                   #newton\n",
-      "A = 1200e-6                   # meter^2\n",
-      "s_x = -P/A                    #stress\n",
-      "t_1 = 25.0                    #for the stresses on ab and cd plane\n",
-      "\n",
-      "#Calculations\n",
-      "s_1 = s_x*(math.cos(math.radians(t_1))**2)\n",
-      "T_1 = -s_x*math.cos(math.radians(t_1))*math.sin(math.radians(t_1))\n",
-      "t_2 = -65.0                   #for the stresses on ad and bc plane\n",
-      "s_2 = s_x*(math.cos(math.radians(t_2))**2)\n",
-      "T_2 = -s_x*math.cos(math.radians(t_2))*math.sin(math.radians(t_2))\n",
-      "\n",
-      "#Result\n",
-      "print \"The normal and shear stresses on the plane ab and cd are\", round((T_1/1E+6),2), round((s_1/1E+6),2), \"MPa respecively\" \n",
-      "print \"respecively The normal and shear stresses on the plane ad and bc are\", round((T_2/1E+6),2), round((s_2/1E+6),2), \"MPa respecively\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The normal and shear stresses on the plane ab and cd are 28.73 -61.6 MPa respecively\n",
-        "respecively The normal and shear stresses on the plane ad and bc are -28.73 -13.4 MPa respecively\n"
-       ]
-      }
-     ],
-     "prompt_number": 4
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.11, page no. 114"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "Calculate the vertical displacement of the joint\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "# Value of s_x based on allowable stresses on glued joint\n",
-      "\n",
-      "#initialisation\n",
-      "s_t = -750.0                                  #psi\n",
-      "t = -50.0                                     #degree\n",
-      "T_t = -500.0                                  #psi\n",
-      "\n",
-      "sg_x_1 = s_t/(math.cos(math.radians(t))**2)\n",
-      "sg_x_2 = -T_t/(math.cos(math.radians(t))*math.sin(math.radians(t)))\n",
-      "\n",
-      "# Value of s_x based on allowable stresses on plastic\n",
-      "\n",
-      "sp_x_1 = -1100.0                              #psi\n",
-      "T_t_p = 600.0                                  #psi\n",
-      "t_p = 45.0                                    #degree\n",
-      "sp_x_2 = -T_t_p/(math.cos(math.radians(t_p))*math.sin(math.radians(t_p)))\n",
-      "\n",
-      "# Minimum width of bar\n",
-      "\n",
-      "P = 8000.0                                    #lb\n",
-      "A = P/sg_x_2\n",
-      "b_min = math.sqrt(abs(A))                        #inch\n",
-      "print \"The minimum width of the bar is\", round(b_min,2), \"inch\"\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The minimum width of the bar is 2.81 inch\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.15, page no. 126"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "Comparison of energy-absorbing capacity with different type of bolts\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "#Bolt with reduced shank diameter\n",
-      "\n",
-      "#initialisation\n",
-      "g = 1.50                     # inch\n",
-      "d = 0.5                      #inch\n",
-      "t = 0.25                     #inch\n",
-      "d_r = 0.406                  #inch\n",
-      "L = 13.5                     #inch\n",
-      "\n",
-      "#calculation\n",
-      "ratio = ((g*(d**2))/(((g-t)*(d_r**2))+(t*(d**2))))              #U2/U1\n",
-      "\n",
-      "print \"The energy absorbing capacity of the bolts with reduced shank diameter\", round(ratio,2)\n",
-      "ratio_1 = ( (((L-t)*(d_r**2))+(t*(d**2))) / ((2*(g-t)*(d_r**2))+2*(t*(d**2))) )         #U3/2U1\n",
-      "print \"The energy absorbing capacity of the long bolts\", round(ratio_1,2)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The energy absorbing capacity of the bolts with reduced shank diameter 1.4\n",
-        "The energy absorbing capacity of the long bolts 4.18\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "    Example 2.16, page no. 133"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "Determine the maximum elongation and tensile stress\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "# Maximum elongation\n",
-      "M = 20                      #kg\n",
-      "g = 9.81                    #m/s^2\n",
-      "L = 2                       #meter\n",
-      "E = 210e9                   #210Gpa\n",
-      "h = 0.15                    #meter\n",
-      "diameter = 0.015            #milimeter\n",
-      "\n",
-      "#Calculations & Result\n",
-      "A = (math.pi/4)*(diameter**2)               #area\n",
-      "D_st = ((M*g*L)/(E*A)) \n",
-      "D_max = D_st*(1+(1+(2*h/D_st))**0.5) \n",
-      "D_max_1 = math.sqrt(2*h*D_st)                # another approach to find D_max\n",
-      "i = D_max / D_st                             # Impact factor\n",
-      "print \"Maximum elongation is\",round((D_max/1E-3),2), \"mm\"  # Maximum tensile stress\n",
-      "s_max = (E*D_max)/L                          #Maximum tensile stress\n",
-      "s_st = (M*g)/A                               #static stress\n",
-      "i_1 = s_max / s_st                           #Impact factor \n",
-      "print \"Maximum tensile stress is \", round((s_max/1E+6),2), \"MPa\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum elongation is 1.79 mm\n",
-        "Maximum tensile stress is  188.13 MPa\n"
-       ]
-      }
-     ],
-     "prompt_number": 7
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.18, page no. 148"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "determine displacement at the lower end of bar in various conditions\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "\n",
-      "#initialisation\n",
-      "P1 = 108000.0                 #Newton\n",
-      "P2 = 27000.0                  #Newton\n",
-      "L = 2.2                     #meter\n",
-      "A = 480.0                     #mm^2\n",
-      "\n",
-      "\n",
-      "#calculations\n",
-      "\n",
-      "# Displacement due to load P1 acting alone\n",
-      "s = (P1/A)                      #stress in MPa\n",
-      "e = (s/70000) + (1/628.2)*((s/260)**10)         #strain\n",
-      "D_b = e*L*1e3                                   #elongation in mm\n",
-      "print \"elongation when only P1 load acting is = \", round(D_b,2), \" mm\"\n",
-      "\n",
-      "# Displacement due to load P2 acting alone\n",
-      "s_1 = (P2/A) #stress in MPa\n",
-      "e_1 = (s_1/70000) + (1/628.2)*((s_1/260)**10) #strain\n",
-      "D_b_1 = e_1*(L/2)*1e3 #elongation in mm (no elongation in lower half)\n",
-      "print \"elongation when only P2 load acting is = \", round(D_b_1,2), \" mm\"\n",
-      "\n",
-      "# Displacement due to both load acting simonmath.taneously\n",
-      "#upper half\n",
-      "s_2 = (P1/A) #stress in MPa\n",
-      "e_2 = (s_2/70000) + (1/628.2)*((s_2/260)**10) #strain\n",
-      "\n",
-      "#lower half\n",
-      "s_3 = (P1+P2)/A #stress in MPa\n",
-      "e_3 = (s_3/70000) + (1/628.2)*((s_3/260)**10) #strain\n",
-      "D_b_2 = ((e_2*L)/2 + (e_3*L)/2) * 1e3 # elongation in mm\n",
-      "print \"elongation when P1 and P2 both loads are acting is = \", round(D_b_2,2), \" mm\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "elongation when only P1 load acting is =  7.9  mm\n",
-        "elongation when only P2 load acting is =  0.88  mm\n",
-        "elongation when P1 and P2 both loads are acting is =  12.21  mm\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Test/chapter2_2.ipynb b/Test/chapter2_2.ipynb
deleted file mode 100755
index c4e1ad0f..00000000
--- a/Test/chapter2_2.ipynb
+++ /dev/null
@@ -1,501 +0,0 @@
-{
- "metadata": {
-  "name": ""
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 2: Axially Loaded Members"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.1, page no. 72"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculating the number of revolutions for the nut\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "\n",
-      "W = 2.0                       #lb\n",
-      "b = 10.5                   #inch\n",
-      "c = 6.4                    #inch\n",
-      "k = 4.2                    #inch\n",
-      "p = 1.0/16.0                   #inch\n",
-      "\n",
-      "#calculation\n",
-      "\n",
-      "n = (W*b)/(c*k*p)          #inch\n",
-      "\n",
-      "#result\n",
-      "\n",
-      "print \" No. of revolution required = \", n, \"revolutions\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " No. of revolution required =  12.5 revolutions\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.2, page no. 74"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "finding maximum allowable load\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "import numpy\n",
-      "\n",
-      "#initialisation\n",
-      "\n",
-      "Fce_ = 2.0                    #dummy variable\n",
-      "Fbd_ = 3.0                    #dummy variable    \n",
-      "Lbd = 480.0                   #mm\n",
-      "Lce = 600.0                  #mm\n",
-      "E = 205e6                   #205Gpa\n",
-      "Abd = 1020.0                  #mm\n",
-      "Ace = 520.0                   #mm\n",
-      "\n",
-      "#calculation\n",
-      "Dbd_ = (Fbd_*Lbd)/(E*Abd)   #dummy variable\n",
-      "Dce_ = (Fce_*Lce)/(E*Ace)   #dummy variable\n",
-      "Da = 1 #limiting value\n",
-      "P = ((((450+225)/225)*(Dbd_ + Dce_) - Dce_ )**(-1)) * Da  \n",
-      "Fce = 2*P # Real value in newton\n",
-      "Fbd = 3*P #real value in newton\n",
-      "Dbd = (Fbd*Lbd)/(E*Abd) #print lacement in mm\n",
-      "Dce = (Fce*Lce)/(E*Ace) # print lacement in mm\n",
-      "a = numpy.degrees(numpy.arctan(((Da+Dce)/675)))  #alpha in degree\n",
-      "\n",
-      "#result\n",
-      "print \"alpha = \", round(a,2), \"degree\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "alpha =  0.11 degree\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.3, page no. 80"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculation if vertical displacement\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "P1 = 2100.0                       #lb\n",
-      "P2 = 5600.0                       #lb\n",
-      "b = 25.0                          #inch\n",
-      "a = 28.0                          #inch\n",
-      "A1 = 0.25                       #inch^2\n",
-      "A2 = 0.15                       #inch^2\n",
-      "L1 = 20.0                         #inch\n",
-      "L2 = 34.8                       #inch\n",
-      "E = 29e6                        #29Gpa\n",
-      "\n",
-      "#Calculations\n",
-      "P3 = (P2*b)/a \n",
-      "Ra = P3-P1\n",
-      "N1 = -Ra \n",
-      "N2 = P1 \n",
-      "D = ((N1*L1)/(E*A1)) + ((N2*L2)/(E*A2))     #print lacement\n",
-      "\n",
-      "#Result\n",
-      "print  \"Downward print lacement is = \", D, \"inch\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Downward print lacement is =  0.0088 inch\n"
-       ]
-      }
-     ],
-     "prompt_number": 4
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.6, page no. 90"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "obtaing formula and calculating allowable load\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#Numerical calculation of allowable load\n",
-      "\n",
-      "d1 = 4.0                      #mm\n",
-      "d2 = 3.0                      #mm\n",
-      "A1 = (math.pi*(d1**2))/4    #area\n",
-      "A2 = (math.pi*(d2**2))/4    #area\n",
-      "L1 = 0.4                    #meter\n",
-      "L2 = 0.3                    #meter\n",
-      "E1 = 72e9                   #Gpa\n",
-      "E2 = 45e9                   #Gpa\n",
-      "f1 = L1/(E1*A1) * 1e6       # To cpmpensate for the mm**2\n",
-      "f2 = L2/(E2*A2) * 1e6 \n",
-      "s1 = 200e6                  #stress\n",
-      "s2 = 175e6                  #stress\n",
-      "\n",
-      "#Calculations\n",
-      "P1 = ( (s1*A1*(4*f1 + f2))/(3*f2) ) * 1e-6      # To cpmpensate for the mm**2\n",
-      "P2 = ( (s2*A2*(4*f1 + f2))/(6*f1) ) * 1e-6 \n",
-      "\n",
-      "#Result\n",
-      "print \"Newton Minimum allowable stress aomong the two P1 and P2 is smaller one, therefore MAS = \", P2"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Newton Minimum allowable stress aomong the two P1 and P2 is smaller one, therefore MAS =  1264.49104307\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.10, page no. 113"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculate stress acting on inclined section &\n",
-      "the complete state of stress\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "P = 90000.0                   #newton\n",
-      "A = 1200e-6                   # meter^2\n",
-      "s_x = -P/A                    #stress\n",
-      "t_1 = 25.0                    #for the stresses on ab and cd plane\n",
-      "\n",
-      "#Calculations\n",
-      "s_1 = s_x*(math.cos(math.radians(t_1))**2)\n",
-      "T_1 = -s_x*math.cos(math.radians(t_1))*math.sin(math.radians(t_1))\n",
-      "t_2 = -65.0                   #for the stresses on ad and bc plane\n",
-      "s_2 = s_x*(math.cos(math.radians(t_2))**2)\n",
-      "T_2 = -s_x*math.cos(math.radians(t_2))*math.sin(math.radians(t_2))\n",
-      "\n",
-      "#Result\n",
-      "print \"The normal and shear stresses on the plane ab and cd are\", round((T_1/1E+6),2), round((s_1/1E+6),2), \"MPa respecively\" \n",
-      "print \"respecively The normal and shear stresses on the plane ad and bc are\", round((T_2/1E+6),2), round((s_2/1E+6),2), \"MPa respecively\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The normal and shear stresses on the plane ab and cd are 28.73 -61.6 MPa respecively\n",
-        "respecively The normal and shear stresses on the plane ad and bc are -28.73 -13.4 MPa respecively\n"
-       ]
-      }
-     ],
-     "prompt_number": 4
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.11, page no. 114"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "Calculate the vertical displacement of the joint\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "# Value of s_x based on allowable stresses on glued joint\n",
-      "\n",
-      "#initialisation\n",
-      "s_t = -750.0                                  #psi\n",
-      "t = -50.0                                     #degree\n",
-      "T_t = -500.0                                  #psi\n",
-      "\n",
-      "sg_x_1 = s_t/(math.cos(math.radians(t))**2)\n",
-      "sg_x_2 = -T_t/(math.cos(math.radians(t))*math.sin(math.radians(t)))\n",
-      "\n",
-      "# Value of s_x based on allowable stresses on plastic\n",
-      "\n",
-      "sp_x_1 = -1100.0                              #psi\n",
-      "T_t_p = 600.0                                  #psi\n",
-      "t_p = 45.0                                    #degree\n",
-      "sp_x_2 = -T_t_p/(math.cos(math.radians(t_p))*math.sin(math.radians(t_p)))\n",
-      "\n",
-      "# Minimum width of bar\n",
-      "\n",
-      "P = 8000.0                                    #lb\n",
-      "A = P/sg_x_2\n",
-      "b_min = math.sqrt(abs(A))                        #inch\n",
-      "print \"The minimum width of the bar is\", round(b_min,2), \"inch\"\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The minimum width of the bar is 2.81 inch\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.15, page no. 126"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "Comparison of energy-absorbing capacity with different type of bolts\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "#Bolt with reduced shank diameter\n",
-      "\n",
-      "#initialisation\n",
-      "g = 1.50                     # inch\n",
-      "d = 0.5                      #inch\n",
-      "t = 0.25                     #inch\n",
-      "d_r = 0.406                  #inch\n",
-      "L = 13.5                     #inch\n",
-      "\n",
-      "#calculation\n",
-      "ratio = ((g*(d**2))/(((g-t)*(d_r**2))+(t*(d**2))))              #U2/U1\n",
-      "\n",
-      "print \"The energy absorbing capacity of the bolts with reduced shank diameter\", round(ratio,2)\n",
-      "ratio_1 = ( (((L-t)*(d_r**2))+(t*(d**2))) / ((2*(g-t)*(d_r**2))+2*(t*(d**2))) )         #U3/2U1\n",
-      "print \"The energy absorbing capacity of the long bolts\", round(ratio_1,2)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The energy absorbing capacity of the bolts with reduced shank diameter 1.4\n",
-        "The energy absorbing capacity of the long bolts 4.18\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "    Example 2.16, page no. 133"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "Determine the maximum elongation and tensile stress\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "# Maximum elongation\n",
-      "M = 20                      #kg\n",
-      "g = 9.81                    #m/s^2\n",
-      "L = 2                       #meter\n",
-      "E = 210e9                   #210Gpa\n",
-      "h = 0.15                    #meter\n",
-      "diameter = 0.015            #milimeter\n",
-      "\n",
-      "#Calculations & Result\n",
-      "A = (math.pi/4)*(diameter**2)               #area\n",
-      "D_st = ((M*g*L)/(E*A)) \n",
-      "D_max = D_st*(1+(1+(2*h/D_st))**0.5) \n",
-      "D_max_1 = math.sqrt(2*h*D_st)                # another approach to find D_max\n",
-      "i = D_max / D_st                             # Impact factor\n",
-      "print \"Maximum elongation is\",round((D_max/1E-3),2), \"mm\"  # Maximum tensile stress\n",
-      "s_max = (E*D_max)/L                          #Maximum tensile stress\n",
-      "s_st = (M*g)/A                               #static stress\n",
-      "i_1 = s_max / s_st                           #Impact factor \n",
-      "print \"Maximum tensile stress is \", round((s_max/1E+6),2), \"MPa\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum elongation is 1.79 mm\n",
-        "Maximum tensile stress is  188.13 MPa\n"
-       ]
-      }
-     ],
-     "prompt_number": 7
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.18, page no. 148"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "determine displacement at the lower end of bar in various conditions\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "\n",
-      "#initialisation\n",
-      "P1 = 108000.0                 #Newton\n",
-      "P2 = 27000.0                  #Newton\n",
-      "L = 2.2                     #meter\n",
-      "A = 480.0                     #mm^2\n",
-      "\n",
-      "\n",
-      "#calculations\n",
-      "\n",
-      "# Displacement due to load P1 acting alone\n",
-      "s = (P1/A)                      #stress in MPa\n",
-      "e = (s/70000) + (1/628.2)*((s/260)**10)         #strain\n",
-      "D_b = e*L*1e3                                   #elongation in mm\n",
-      "print \"elongation when only P1 load acting is = \", round(D_b,2), \" mm\"\n",
-      "\n",
-      "# Displacement due to load P2 acting alone\n",
-      "s_1 = (P2/A) #stress in MPa\n",
-      "e_1 = (s_1/70000) + (1/628.2)*((s_1/260)**10) #strain\n",
-      "D_b_1 = e_1*(L/2)*1e3 #elongation in mm (no elongation in lower half)\n",
-      "print \"elongation when only P2 load acting is = \", round(D_b_1,2), \" mm\"\n",
-      "\n",
-      "# Displacement due to both load acting simonmath.taneously\n",
-      "#upper half\n",
-      "s_2 = (P1/A) #stress in MPa\n",
-      "e_2 = (s_2/70000) + (1/628.2)*((s_2/260)**10) #strain\n",
-      "\n",
-      "#lower half\n",
-      "s_3 = (P1+P2)/A #stress in MPa\n",
-      "e_3 = (s_3/70000) + (1/628.2)*((s_3/260)**10) #strain\n",
-      "D_b_2 = ((e_2*L)/2 + (e_3*L)/2) * 1e3 # elongation in mm\n",
-      "print \"elongation when P1 and P2 both loads are acting is = \", round(D_b_2,2), \" mm\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "elongation when only P1 load acting is =  7.9  mm\n",
-        "elongation when only P2 load acting is =  0.88  mm\n",
-        "elongation when P1 and P2 both loads are acting is =  12.21  mm\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Test/screenshots/screen1.png b/Test/screenshots/screen1.png
deleted file mode 100755
index 2e923aea..00000000
--- a/Test/screenshots/screen1.png
+++ /dev/null
diff --git a/Test/screenshots/screen1_1.png b/Test/screenshots/screen1_1.png
deleted file mode 100755
index 2e923aea..00000000
--- a/Test/screenshots/screen1_1.png
+++ /dev/null
diff --git a/Test/screenshots/screen2.png b/Test/screenshots/screen2.png
deleted file mode 100755
index eb6ad8e1..00000000
--- a/Test/screenshots/screen2.png
+++ /dev/null
diff --git a/Test/screenshots/screen2_1.png b/Test/screenshots/screen2_1.png
deleted file mode 100755
index eb6ad8e1..00000000
--- a/Test/screenshots/screen2_1.png
+++ /dev/null
diff --git a/Test/screenshots/screen2_2.png b/Test/screenshots/screen2_2.png
deleted file mode 100755
index eb6ad8e1..00000000
--- a/Test/screenshots/screen2_2.png
+++ /dev/null
diff --git a/Test/screenshots/screen2_3.png b/Test/screenshots/screen2_3.png
deleted file mode 100755
index eb6ad8e1..00000000
--- a/Test/screenshots/screen2_3.png
+++ /dev/null
diff --git a/Test/screenshots/screen3.png b/Test/screenshots/screen3.png
deleted file mode 100755
index ff023b0d..00000000
--- a/Test/screenshots/screen3.png
+++ /dev/null
diff --git a/Test/screenshots/screen3_1.png b/Test/screenshots/screen3_1.png
deleted file mode 100755
index ff023b0d..00000000
--- a/Test/screenshots/screen3_1.png
+++ /dev/null
diff --git a/Test/screenshots/screen3_2.png b/Test/screenshots/screen3_2.png
deleted file mode 100755
index ff023b0d..00000000
--- a/Test/screenshots/screen3_2.png
+++ /dev/null
diff --git a/TestContribution/Chapter2.ipynb b/TestContribution/Chapter2.ipynb
deleted file mode 100755
index f5907f3a..00000000
--- a/TestContribution/Chapter2.ipynb
+++ /dev/null
@@ -1,322 +0,0 @@
-{

- "metadata": {

-  "name": "",

-  "signature": "sha256:d3b8a40a5268a38ad3fc311ebed2078460c9192ee65f2f5e3922c8f65a52bf49"

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 2: Properties of Pure Substances"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex2.1:pg-22"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "# initialization of variables\n",

-      "\n",

-      "m=1;  #mass of saturated water in kg\n",

-      "\n",

-      "    # All the necessary values are taken from table C-2\n",

-      " \n",

-      "# part (a)\n",

-      "\n",

-      "P=0.001; # Pressure in MPa\n",

-      "vf=0.001; #specific volume of saturated liquid at 0.001 Mpa in Kg/m^3\n",

-      "vg=129.2; # specific volume of saturated vapour at 0.001 Mpa in Kg/m^3\n",

-      "deltaV=m*(vg-vf) # by properties of pure substance \n",

-      "# result\n",

-      "print \"The Volume change at pressure \",(P),\" MPa is\",round(deltaV,1),\" m^3/kg \\n\"\n",

-      "\n",

-      "# part (b) \n",

-      "\n",

-      "P=0.10;  # Pressure in MPa\n",

-      "vf=0.001; # specific volume of saturated liquid at 0.26 MPa( it is same from at 0.2 and 0.3 MPa upto 4 decimals)\n",

-      "vg=1.694;  # specific volume of saturated vapour at 0.1 Mpa\n",

-      "deltaV=m*(vg-vf) # by properties of pure substance\n",

-      "# result\n",

-      "print \"The Volume change at pressure \",(P),\" MPa is\",round(deltaV,3),\" m^3/kg \\n\"\n",

-      "\n",

-      "# part (c) \n",

-      "P=10;  # Pressure in MPa\n",

-      "vf=0.00145; # specific volume of saturated liquid at 10 MPa\n",

-      "vg=0.01803; # specific volume of saturated vapour at 10 MPa\n",

-      "deltaV=m*(vg-vf) # by properties of pure substance \n",

-      "# result\n",

-      "print \"The Volume change at pressure \",(P),\" MPa is\",round(deltaV,5),\" m^3/kg \\n\""

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "The Volume change at pressure  0.001  MPa is 129.2  m^3/kg \n",

-        "\n",

-        "The Volume change at pressure  0.1  MPa is 1.693  m^3/kg \n",

-        "\n",

-        "The Volume change at pressure  10  MPa is 0.01658  m^3/kg \n",

-        "\n"

-       ]

-      }

-     ],

-     "prompt_number": 8

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex2.2:pg-23"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "#    initialization of variables\n",

-      "m=4.0 # mass of water in kg\n",

-      "V=1.0 # volume in m^3\n",

-      "T=150 # temperature of water in degree centigrade\n",

-      "\n",

-      "# TABLE C-1 is used for values in wet region\n",

-      "# Part (a)\n",

-      "P=475.8 # pressure in KPa in wet region at temperature of 150 *C\n",

-      "print \" The pressure is\",round(P,1),\" kPa \\n\"\n",

-      "\n",

-      "# Part (b)\n",

-      "#first we determine the dryness fraction\n",

-      "v=V/m # specific volume of water\n",

-      "vg=0.3928 #  specific volume of saturated vapour @150 degree celsius\n",

-      "vf=0.00109 # specific volume of saturated liquid @150 degree celsius\n",

-      "x=(v-vf)/(vg-vf); # dryness fraction\n",

-      "mg=m*x; # mass of vapour\n",

-      "print \" The mass of vapour present is\",round(mg,3),\" kg \\n\"\n",

-      "\n",

-      "# Part(c) \n",

-      "Vg=vg*mg; # volume of vapour\n",

-      "print \" The volume of vapour is\",round(Vg,4),\" m^3\""

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        " The pressure is 475.8  kPa \n",

-        "\n",

-        " The mass of vapour present is 2.542  kg \n",

-        "\n",

-        " The volume of vapour is 0.9984  m^3\n"

-       ]

-      }

-     ],

-     "prompt_number": 12

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex2.3:pg-23"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "#    initialization of variables\n",

-      "m=4 # mass of water in kg\n",

-      "P=220 # pressure in KPa\n",

-      "x=0.8 # quality of steam\n",

-      "\n",

-      "# Table C-2 is used for values\n",

-      "\n",

-      "vg=(P-200)*(0.6058-0.8857)/(300-200)+0.8857 # specific volume of saturated vapour @ given pressure by interpolating\n",

-      "vf=0.0011 # specific volume of saturated liquid at 220 KPa\n",

-      "v=vf+x*(vg-vf)# property of pure substance\n",

-      "V=m*v # total volume\n",

-      "#result\n",

-      "print \"The Total volume of the mixture is \",round(V,3),\" m^3\""

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "The Total volume of the mixture is  2.656  m^3\n"

-       ]

-      }

-     ],

-     "prompt_number": 5

-    },

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Ex2.4:pg-23"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "#   initialization of variables\n",

-      "m=2 # mass of water in lb\n",

-      "P=540 # pressure in psi\n",

-      "T=700 # temperature in degree fahrenheit\n",

-      " # Table C-3E is used for values\n",

-      "v=1.3040+(P-500)*(1.0727-1.3030)/(600-500) # specific volue by interpolatin between 500 and 600 psi\n",

-      "V=m*v # final volume\n",

-      "print \"The Final Volume is\",round(V,3),\" ft^3\"\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "The Final Volume is 2.424  ft^3\n"

-       ]

-      }

-     ],

-     "prompt_number": 9

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex2.5:pg-25"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "#    initialization of variables\n",

-      "V=0.6 # volume of tyre in m^3\n",

-      "Pgauge=200 # gauge pressure in KPa\n",

-      "T=20+273 # temperature converted to kelvin\n",

-      "Patm=100 # atmospheric pressure in KPa\n",

-      "R=287 # gas constant in Nm/kg.K\n",

-      "Pabs=(Pgauge+Patm)*1000 # calculating absolute pressue in Pa \n",

-      "\n",

-      "m=Pabs*V/(R*T)# mass from ideal gas equation\n",

-      "print \"The Mass of air is\",round(m,2),\" Kg\"\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "The Mass of air is 2.14  Kg\n"

-       ]

-      }

-     ],

-     "prompt_number": 10

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex2.6:pg-26"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#    initialization of variables\n",

-      "T=500+273 # temperature of steam in kelvin\n",

-      "rho=24.0 # density in Kg/m^3\n",

-      "R=0.462 # gas constant from Table B-2\n",

-      "v=1/rho # specific volume and density relation\n",

-      "# PART (a)\n",

-      "P=rho*R*T # from Ideal gas equation\n",

-      "print \" PART (a) The Pressure is \",int(P),\" KPa \\n\"\n",

-      "# answer is approximated in textbook\n",

-      "\n",

-      "# PART (b)\n",

-      "a=1.703 #  van der Waal's constant a value from Table B-8\n",

-      "b=0.00169 # van der Waal's constant b value from Table B-8\n",

-      "P=(R*T/(v-b))-(a/v**2) # Pressure from van der Waals equation\n",

-      "print \" PART (b) The Pressure is \",int(P),\" KPa \\n\"\n",

-      "# answer is approximated in textbook\n",

-      "\n",

-      "# PART (c)\n",

-      "a=43.9 # van der Waal's constant a value from Table B-8\n",

-      "b=0.00117 # van der Waal's constant b value from Table B-8\n",

-      "\n",

-      "P=(R*T/(v-b))-(a/(v*(v+b)*math.sqrt(T))) # Redlich-Kwong equation\n",

-      "print \" PART (c) The Pressure is \",int(P),\" KPa \\n\"\n",

-      "# answer is approximated in textbook\n",

-      "\n",

-      "# PART (d)\n",

-      "Tcr=947.4 # compressibilty temperature from table B-3\n",

-      "Pcr=22100 # compressibility pressure from table B-3\n",

-      "\n",

-      "TR=T/Tcr # reduced temperature\n",

-      "PR=P/Pcr # reduced pressure\n",

-      "Z=0.93 # from compressiblility chart\n",

-      "P=Z*R*T/v # Pressure in KPa\n",

-      "print \" PART (d) The Pressure is \",int(P),\" KPa \\n\"\n",

-      "# answer is approximated in textbook\n",

-      "\n",

-      "# PART (e)\n",

-      "P=8000 # pressure from steam table @ 500*c and v= 0.0417 m^3\n",

-      "print \" PART (e) The Pressure is \",int(P),\" KPa \\n\"\n",

-      "# answer is approximated in textbook"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        " PART (a) The Pressure is  8571  KPa \n",

-        "\n",

-        " PART (b) The Pressure is  7952  KPa \n",

-        "\n",

-        " PART (c) The Pressure is  7934  KPa \n",

-        "\n",

-        " PART (d) The Pressure is  7971  KPa \n",

-        "\n",

-        " PART (e) The Pressure is  8000  KPa \n",

-        "\n"

-       ]

-      }

-     ],

-     "prompt_number": 13

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/TestContribution/README.txt b/TestContribution/README.txt
deleted file mode 100755
index e9a60064..00000000
--- a/TestContribution/README.txt
+++ /dev/null
@@ -1,10 +0,0 @@
-Contributed By: Test Contributor
-Course: mtech
-College/Institute/Organization: IIT
-Department/Designation: CS
-Book Title: TestContribution
-Author: TestContribution
-Publisher: TestContribution
-Year of publication: Test
-Isbn: TestContribution
-Edition: TestContributio
\ No newline at end of file
diff --git a/TestContribution/abhisheksharma.ipynb b/TestContribution/abhisheksharma.ipynb
deleted file mode 100755
index e09e86cb..00000000
--- a/TestContribution/abhisheksharma.ipynb
+++ /dev/null
@@ -1,946 +0,0 @@
-{

- "metadata": {

-  "name": "",

-  "signature": "sha256:54ccd26f8e7172369b740037968be286180ddfff5f2fc10ebe6be83fc34647f9"

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "HF,VHF AND UHF ANTENNAS (CHAPTER 6)"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "EXAMPLE 6.1,PAGE NUMBER 278 "

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "from math import pi,sin\n",

-      "\n",

-      "# Variable Declaration\n",

-      "\n",

-      "f = 30        # frequency in MHz\n",

-      "f = 30*10**6  # frequency in Hz\n",

-      "c = 3*10**8   # speed of light in m/s\n",

-      "lamda = c/f   # wavelength in meter\n",

-      "Delta = 30    # angle of elevation in Degrees\n",

-      "\n",

-      "#calculation\n",

-      "\n",

-      "H = lamda/(4 * sin(Delta*pi/180))     # Rhombic height in m\n",

-      "l = lamda/(2 * sin(Delta*pi/180) **2) # wire length in m\n",

-      "phi = 90-Delta # tilt angle in Degrees\n",

-      "\n",

-      "#Results\n",

-      "\n",

-      "print \"Rhombic height is:\",round(H,2),\"meter\"\n",

-      "print \"Tilt angle is:\",round(phi,2),\"degrees\"\n",

-      "print \"length of wire is:\",round(l,2),\"meter\"\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Rhombic height is: 5.0 meter\n",

-        "Tilt angle is: 60.0 degrees\n",

-        "length of wire is: 20.0 meter\n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "EXAMPLE 6.2,PAGE NUMBER 278"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "from math import pi,sin\n",

-      "\n",

-      "\n",

-      "# Variable Declaration\n",

-      "\n",

-      "f = 20        # frequency in MHz\n",

-      "f = 20*10**6  # frequency in Hz\n",

-      "c = 3*10**8   # speed of light in m/s\n",

-      "lamda = c/f   # wavelength in meter\n",

-      "\n",

-      "#calculation\n",

-      "\n",

-      "Delta = 10    # angle of elevation in Degrees\n",

-      "H = lamda/(4 * sin(Delta*pi/180))     # Rhombic height in m\n",

-      "l = lamda/(2 * sin(Delta*pi/180) **2) # wire length in m\n",

-      "phi = 90-Delta # tilt angle in Degrees\n",

-      "\n",

-      "#Results\n",

-      "\n",

-      "print \"Rhombic height is:\",round(H,3),\"meter\"\n",

-      "print \"Tilt angle is:\",round(phi,2),\"degrees\"\n",

-      "print \"length of wire is:\",round(l,3),\"meter\"\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Rhombic height is: 21.595 meter\n",

-        "Tilt angle is: 80.0 degrees\n",

-        "length of wire is: 248.726 meter\n"

-       ]

-      }

-     ],

-     "prompt_number": 2

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "EXAMPLE 6.3,PAGE NUMBER 279-281"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "from math import pi,sin,cos\n",

-      "\n",

-      "\n",

-      "\n",

-      "# Variable Declaration\n",

-      "\n",

-      "f = 30        # frequency in MHz\n",

-      "f = 30*10**6  # frequency in Hz\n",

-      "c = 3*10**8   # speed of light in m/s\n",

-      "lamda = c/f   # wavelength in meter\n",

-      "\n",

-      "#calculation and results:\n",

-      "\n",

-      "\n",

-      "\n",

-      "print \"for Delta = 10 degrees\"\n",

-      "\n",

-      "\n",

-      "Delta1 = 10    # angle of elevation in Degrees\n",

-      "H1 = lamda/(4 * sin(Delta1*pi/180))     # Rhombic height in m\n",

-      "l1 = lamda/(2 * sin(Delta1*pi/180) **2) # wire length in m\n",

-      "phi1 = 90-Delta1 # tilt angle in Degrees\n",

-      "print \"Rhombic height is:\",round(H1,3),\"meter\"\n",

-      "print \"Tilt angle is:\",round(phi1,2),\"degrees\"\n",

-      "print \"length of wire is:\",round(l1,2),\"meter\"\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "print \"for Delta = 15 degrees\"\n",

-      "\n",

-      "\n",

-      "Delta2 = 15    # angle of elevation in Degrees\n",

-      "H2 = lamda/(4 * sin(Delta2*pi/180))     # Rhombic height in m\n",

-      "l2 = lamda/(2 * sin(Delta2*pi/180) **2) # wire length in m\n",

-      "phi2 = 90-Delta2 # tilt angle in Degrees\n",

-      "print \"Rhombic height is:\",round(H2,3),\"meter\"\n",

-      "print \"Tilt angle is:\",round(phi2,2),\"degrees\"\n",

-      "print \"length of wire is:\",round(l2,2),\"meter\"\n",

-      "\n",

-      "\n",

-      "\n",

-      "print \"for Delta = 20 degrees\"\n",

-      "\n",

-      "\n",

-      "Delta3 = 20    # angle of elevation in Degrees\n",

-      "H3 = lamda/(4 * sin(Delta3*pi/180))     # Rhombic height in m\n",

-      "l3 = lamda/(2 * sin(Delta3*pi/180) **2) # wire length in m\n",

-      "phi3 = 90-Delta3 # tilt angle in Degrees\n",

-      "print \"Rhombic height is:\",round(H3,3),\"meter\"\n",

-      "print \"Tilt angle is:\",round(phi3,2),\"degrees\"\n",

-      "print \"length of wire is:\",round(l3,2),\"meter\"\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "print \"for Delta = 25 degrees\"\n",

-      "\n",

-      "\n",

-      "Delta4 = 25    # angle of elevation in Degrees\n",

-      "H4 = lamda/(4 * sin(Delta4*pi/180))     # Rhombic height in m\n",

-      "l4 = lamda/(2 * sin(Delta4*pi/180) **2) # wire length in m\n",

-      "phi4 = 90-Delta4 # tilt angle in Degrees\n",

-      "print \"Rhombic height is:\",round(H4,3),\"meter\"\n",

-      "print \"Tilt angle is:\",round(phi4,2),\"degrees\"\n",

-      "print \"length of wire is:\",round(l4,2),\"meter\"\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "print \"for Delta = 30 degrees\"\n",

-      "\n",

-      "\n",

-      "Delta5 = 30    # angle of elevation in Degrees\n",

-      "H5 = lamda/(4 * sin(Delta5*pi/180))     # Rhombic height in m\n",

-      "l5 = lamda/(2 * sin(Delta5*pi/180) **2) # wire length in m\n",

-      "phi5 = 90-Delta5 # tilt angle in Degrees\n",

-      "print \"Rhombic height is:\",round(H5,3),\"meter\"\n",

-      "print \"Tilt angle is:\",round(phi5,2),\"degrees\"\n",

-      "print \"length of wire is:\",round(l5,2),\"meter\"\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "print \"for Delta = 35 degrees\"\n",

-      "\n",

-      "\n",

-      "Delta6 = 35    # angle of elevation in Degrees\n",

-      "H6 = lamda/(4 * sin(Delta6*pi/180))     # Rhombic height in m\n",

-      "l6 = lamda/(2 * sin(Delta6*pi/180) **2) # wire length in m\n",

-      "phi6 = 90-Delta6 # tilt angle in Degrees\n",

-      "print \"Rhombic height is:\",round(H6,3),\"meter\"\n",

-      "print \"Tilt angle is:\",round(phi6,2),\"degrees\"\n",

-      "print \"length of wire is:\",round(l6,2),\"meter\"\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "print \"for Delta = 40 degrees\"\n",

-      "\n",

-      "\n",

-      "Delta7 = 40    # angle of elevation in Degrees\n",

-      "H7 = lamda/(4 * sin(Delta7*pi/180))     # Rhombic height in m\n",

-      "l7 = lamda/(2 * sin(Delta7*pi/180) **2) # wire length in m\n",

-      "phi7 = 90-Delta7 # tilt angle in Degrees\n",

-      "print \"Rhombic height is:\",round(H7,3),\"meter\"\n",

-      "print \"Tilt angle is:\",round(phi7,2),\"degrees\"\n",

-      "print \"length of wire is:\",round(l7,2),\"meter\"\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for Delta = 10 degrees\n",

-        "Rhombic height is: 14.397 meter\n",

-        "Tilt angle is: 80.0 degrees\n",

-        "length of wire is: 165.82 meter\n",

-        "for Delta = 15 degrees\n",

-        "Rhombic height is: 9.659 meter\n",

-        "Tilt angle is: 75.0 degrees\n",

-        "length of wire is: 74.64 meter\n",

-        "for Delta = 20 degrees\n",

-        "Rhombic height is: 7.31 meter\n",

-        "Tilt angle is: 70.0 degrees\n",

-        "length of wire is: 42.74 meter\n",

-        "for Delta = 25 degrees\n",

-        "Rhombic height is: 5.916 meter\n",

-        "Tilt angle is: 65.0 degrees\n",

-        "length of wire is: 27.99 meter\n",

-        "for Delta = 30 degrees\n",

-        "Rhombic height is: 5.0 meter\n",

-        "Tilt angle is: 60.0 degrees\n",

-        "length of wire is: 20.0 meter\n",

-        "for Delta = 35 degrees\n",

-        "Rhombic height is: 4.359 meter\n",

-        "Tilt angle is: 55.0 degrees\n",

-        "length of wire is: 15.2 meter\n",

-        "for Delta = 40 degrees\n",

-        "Rhombic height is: 3.889 meter\n",

-        "Tilt angle is: 50.0 degrees\n",

-        "length of wire is: 12.1 meter\n"

-       ]

-      }

-     ],

-     "prompt_number": 3

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "EXAMPLE 6.4,PAGE NUMBER 281"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "from math import pi,sin,cos\n",

-      "\n",

-      "\n",

-      "\n",

-      "# Variable Declaration\n",

-      "\n",

-      "f = 30        # frequency in MHz\n",

-      "f = 30*10**6  # frequency in Hz\n",

-      "c = 3*10**8   # speed of light in m/s\n",

-      "lamda = c/f   # wavelength in meter\n",

-      "Delta = 30    # angle of elevation in Degrees\n",

-      "\n",

-      "#calculation\n",

-      "\n",

-      "k = 0.74      # constant\n",

-      "H = lamda/(4 * sin(Delta*pi/180))     # Rhombic height in m\n",

-      "l = lamda/(2 * sin(Delta*pi/180) **2)*k # wire length in m\n",

-      "phi = 90-Delta # tilt angle in Degrees\n",

-      "\n",

-      "#Results\n",

-      "\n",

-      "print \"Rhombic height is:\",round(H,2),\"meter\"\n",

-      "print \"Tilt angle is:\",round(phi,2),\"degrees\"\n",

-      "print \"length of wire is:\",round(l,2),\"meter\"\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Rhombic height is: 5.0 meter\n",

-        "Tilt angle is: 60.0 degrees\n",

-        "length of wire is: 14.8 meter\n"

-       ]

-      }

-     ],

-     "prompt_number": 4

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "EXAMPLE 6.5,PAGE NUMBER 282"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "from math import pi,sin\n",

-      "\n",

-      "\n",

-      "# Variable Declaration\n",

-      "\n",

-      "f = 20        # frequency in MHz\n",

-      "f = 20*10**6  # frequency in Hz\n",

-      "c = 3*10**8   # speed of light in m/s\n",

-      "lamda = c/f   # wavelength in meter\n",

-      "Delta = 20    # angle of elevation in Degrees\n",

-      "k = 0.74      # constant\n",

-      "\n",

-      "#calculation\n",

-      "\n",

-      "H = lamda/(4 * sin(Delta*pi/180))     # Rhombic height in m\n",

-      "l = lamda/(2 * sin(Delta*pi/180) **2)*k # wire length in m\n",

-      "phi = 90-Delta # tilt angle in Degrees\n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "\n",

-      "\n",

-      "print \"Rhombic height is:\",round(H,2),\"meter\"\n",

-      "print \"Tilt angle is:\",round(phi,2),\"degrees\"\n",

-      "print \"length of wire is:\",round(l,2),\"meter\"\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Rhombic height is: 10.96 meter\n",

-        "Tilt angle is: 70.0 degrees\n",

-        "length of wire is: 47.44 meter\n"

-       ]

-      }

-     ],

-     "prompt_number": 5

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "EXAMPLE 6.6,PAGE NUMBER 282"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "from __future__ import division\n",

-      "\n",

-      "\n",

-      "\n",

-      "# Variable Declaration\n",

-      "\n",

-      "\n",

-      "f_MHz = 172        # frequency in MHz\n",

-      "c = 3*10**8        # speed of light in m/s\n",

-      "\n",

-      "#calculation\n",

-      "\n",

-      "lamda = c/f_MHz    # wavelength in m\n",

-      "La = 478/f_MHz     # length of driven element in feet\n",

-      "Lr = 492/f_MHz     # length of reflector in feet\n",

-      "Ld = 461.5/f_MHz   # length of director in feet\n",

-      "S = 142/f_MHz      # element spacing in feet\n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "\n",

-      "\n",

-      "print \"length of driven element is:\", round(La,2),\"feet\"\n",

-      "print \"length of reflector is:\", round(Lr,2),\"feet\"\n",

-      "print \"length of director is:\", round(Ld,3),\"feet\"\n",

-      "print \"element spacing is:\",round(S,3),\"feet\"\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "length of driven element is: 2.78 feet\n",

-        "length of reflector is: 2.86 feet\n",

-        "length of director is: 2.683 feet\n",

-        "element spacing is: 0.826 feet\n"

-       ]

-      }

-     ],

-     "prompt_number": 6

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "EXAMPLE 6.7,PAGE NUMBER 283"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "from __future__ import division\n",

-      "\n",

-      "# Variable Declaration\n",

-      "\n",

-      "\n",

-      "G = 12        # required gain in dB\n",

-      "f = 200       # frequency in MHz \n",

-      "f = 200*10**6  # frequency in Hz\n",

-      "c = 3*10**8    # speed of light in m/s\n",

-      "\n",

-      "#calculations\n",

-      "\n",

-      "\n",

-      "lamda = c/f   # wavelength in m\n",

-      "La = 0.46*lamda   # length of driven element in m    (note: in book La is given 0.416*lamda misprint)\n",

-      "Lr = 0.475*lamda  # length of reflector in m\n",

-      "Ld1 = 0.44*lamda  # length of director1 in m\n",

-      "Ld2 = 0.44*lamda  # length of director2 in m\n",

-      "Ld3 = 0.43*lamda  # length of director3 in m\n",

-      "Ld4 = 0.40*lamda  # length of director4 in m\n",

-      "SL = 0.25*lamda   # spacing between reflector and driver in m\n",

-      "Sd = 0.31*lamda   # spacing director and driving element in m\n",

-      "d = 0.01*lamda    # diameter of elements in m\n",

-      "l = 1.5*lamda     # length of array in m\n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "\n",

-      "\n",

-      "print \"length of driven element is:\" ,round(La,2),\"m\"\n",

-      "print \"length of reflector is:\",round(Lr,4),\"m\"\n",

-      "print \"length of director1 is:\",round(Ld1,2),\"m\"\n",

-      "print \"length of director2 is:\",round(Ld2,2),\"m\"\n",

-      "print \"length of director3 is:\",round(Ld3,3),\"m\"\n",

-      "print \"length of director4 is:\",round(Ld4,2),\"m\"\n",

-      "print \"spacing between reflector and driver is:\",round(SL,3),\"m\"\n",

-      "print \"spacing director and driving element is:\",round(Sd,3),\"m\"\n",

-      "print \"diameter of elements is:\",round(d,3),\"m\"\n",

-      "print \"length of array is:\",round(l,2),\"m\"\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "length of driven element is: 0.69 m\n",

-        "length of reflector is: 0.7125 m\n",

-        "length of director1 is: 0.66 m\n",

-        "length of director2 is: 0.66 m\n",

-        "length of director3 is: 0.645 m\n",

-        "length of director4 is: 0.6 m\n",

-        "spacing between reflector and driver is: 0.375 m\n",

-        "spacing director and driving element is: 0.465 m\n",

-        "diameter of elements is: 0.015 m\n",

-        "length of array is: 2.25 m\n"

-       ]

-      }

-     ],

-     "prompt_number": 7

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "EXAMPLE 6.8,PAGE NUMBER 283"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "from __future__ import division\n",

-      "from math import atan\n",

-      "\n",

-      "\n",

-      "# Variable Declaration\n",

-      "\n",

-      "\n",

-      "G = 9             # required gain in dB\n",

-      "f_l = 125         # lowest frequency in MHz\n",

-      "f_l = 125*10**6   # lowest frequency in Hz\n",

-      "f_h = 500         # highest frequency in MHz\n",

-      "f_h = 500*10**6   # lowest frequency in Hz\n",

-      "c = 3*10**8       # speed of light in m/s\n",

-      "tau = 0.861       # scaling factor\n",

-      "sigma = 0.162     # spacing factor\n",

-      "\n",

-      "\n",

-      "#calculation\n",

-      "\n",

-      "\n",

-      "lamda_l = c/f_l  # longest wavelength in m\n",

-      "lamda_s = c/f_h  # shortest wavelength in m\n",

-      "alpha = 2*atan((1-tau)/(4*sigma))  # wedge angle in Degrees\n",

-      "L1 =  lamda_l/2  # in m\n",

-      "L2 = tau*L1  # in m\n",

-      "L3 = tau*L2  # in m\n",

-      "L4 = tau*L3  # in m\n",

-      "L5 = tau*L4  # in m\n",

-      "L6 = tau*L5  # in m\n",

-      "L7 = tau*L6  # in m\n",

-      "L8 = tau*L7  # in m\n",

-      "L9 = tau*L8  # in m\n",

-      "L10 = tau*L9  # in m\n",

-      "L11 = tau*L10  # in m\n",

-      "\n",

-      "# element spacing relation\n",

-      "#formula : sn = 2*sigma*Ln\n",

-      "\n",

-      "\n",

-      "S1 = 2*sigma*L1  # in m\n",

-      "S2 = 2*sigma*L2  # in m\n",

-      "S3 = 2*sigma*L3  # in m\n",

-      "S4 = 2*sigma*L4  # in m\n",

-      "S5 = 2*sigma*L5  # in m\n",

-      "S6 = 2*sigma*L6  # in m\n",

-      "S7 = 2*sigma*L7  # in m\n",

-      "S8 = 2*sigma*L8  # in m\n",

-      "S9 = 2*sigma*L9  # in m\n",

-      "S10 = 2*sigma*L10  # in m\n",

-      "S11 = 2*sigma*L11  # in m\n",

-      "\n",

-      "\n",

-      "\n",

-      "#results\n",

-      "\n",

-      "\n",

-      "print(\"designing of log-periodic antenna:\")\n",

-      "\n",

-      "print \"L1 is:\",round(L1,4),\"m\"\n",

-      "print \"L2 is:\",round(L2,4),\"m\"\n",

-      "print \"L3 is:\",round(L3,4),\"m\"\n",

-      "print \"L4 is:\",round(L4,4),\"m\"\n",

-      "print \"L5 is:\",round(L5,4),\"m\"\n",

-      "print \"L6 is:\",round(L6,4),\"m\"\n",

-      "print \"L7 is:\",round(L7,4),\"m\"\n",

-      "print \"L8 is:\",round(L8,4),\"m\"\n",

-      "print \"L9 is:\",round(L9,4),\"m\"\n",

-      "print \"L10 is:\",round(L10,4),\"m\"\n",

-      "print \"L11 is:\",round(L11,4),\"m\"\n",

-      "\n",

-      "print \"elements spacing relation:\"\n",

-      "\n",

-      "print \"S1 is:\",round(S1,4),\"m\"\n",

-      "print \"S2 is:\",round(S2,4),\"m\"\n",

-      "print \"S3 is:\",round(S3,4),\"m\"\n",

-      "print \"S4 is:\",round(S4,4),\"m\"\n",

-      "print \"S5 is:\",round(S5,4),\"m\"\n",

-      "print \"S6 is:\",round(S6,4),\"m\"\n",

-      "print \"S7 is:\",round(S7,4),\"m\"\n",

-      "print \"S8 is:\",round(S8,4),\"m\"\n",

-      "print \"S9 is:\",round(S9,4),\"m\"\n",

-      "print \"S10 is:\",round(S10,4),\"m\"\n",

-      "print \"S11 is:\",round(S11,4),\"m\"\n",

-      "\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "designing of log-periodic antenna:\n",

-        "L1 is: 1.2 m\n",

-        "L2 is: 1.0332 m\n",

-        "L3 is: 0.8896 m\n",

-        "L4 is: 0.7659 m\n",

-        "L5 is: 0.6595 m\n",

-        "L6 is: 0.5678 m\n",

-        "L7 is: 0.4889 m\n",

-        "L8 is: 0.4209 m\n",

-        "L9 is: 0.3624 m\n",

-        "L10 is: 0.312 m\n",

-        "L11 is: 0.2687 m\n",

-        "elements spacing relation:\n",

-        "S1 is: 0.3888 m\n",

-        "S2 is: 0.3348 m\n",

-        "S3 is: 0.2882 m\n",

-        "S4 is: 0.2482 m\n",

-        "S5 is: 0.2137 m\n",

-        "S6 is: 0.184 m\n",

-        "S7 is: 0.1584 m\n",

-        "S8 is: 0.1364 m\n",

-        "S9 is: 0.1174 m\n",

-        "S10 is: 0.1011 m\n",

-        "S11 is: 0.087 m\n"

-       ]

-      }

-     ],

-     "prompt_number": 8

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "EXAMPLE 6.9,PAGE NUMBER 285"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "from math import pi,cos,sqrt\n",

-      "\n",

-      "\n",

-      "# Variable Declaration\n",

-      "\n",

-      "E_rms = 10  # electric field in mV/m\n",

-      "E_rms = 10*10 **-3  # electric field in V/m\n",

-      "f = 2  # frequency in MHz\n",

-      "f = 2*10 **6  # frequency in Hz\n",

-      "N = 10  # number of turns\n",

-      "phi = 0  # angle between the plane of loop and direction of incident wave in Degrees\n",

-      "S = 1.4  # area of loop antenna in m **2\n",

-      "c = 3*10 **8  # speed of light in m/s\n",

-      "\n",

-      "#calculation\n",

-      "\n",

-      "lamda = c/f  # wavelength in m\n",

-      "E_max = sqrt(2)*E_rms  # electric field in V/m\n",

-      "V_rms = (2*pi*E_max*S*N/lamda)*cos(phi)  # induced voltage\n",

-      "\n",

-      "#Result\n",

-      "\n",

-      "print \"induced voltage is:\",round(V_rms*1000,2),\"mV\"\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "induced voltage is: 8.29 mV\n"

-       ]

-      }

-     ],

-     "prompt_number": 9

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "EXAMPLE 6.10,PAGE NUMBER 285"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "\n",

-      "# Variable Declaration\n",

-      "\n",

-      "\n",

-      "D = 0.5  # diameter of loop antenna in m\n",

-      "a = D/2  # radius of loop antenna in m\n",

-      "f = 1  # frequency in MHz\n",

-      "f = 1*10**6  # frequency in Hz\n",

-      "c = 3*10**8  # speed of light in m/s\n",

-      "\n",

-      "#calculation\n",

-      "\n",

-      "lamda = c/f  # wavelength in m\n",

-      "Rr = 3720*(a/lamda)  # radiation resistance of loop antenna in ohm\n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "\n",

-      "print \"radiation resistance of loop antenna is:\",Rr,\"ohm\"\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "radiation resistance of loop antenna is: 3.1 ohm\n"

-       ]

-      }

-     ],

-     "prompt_number": 10

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "EXAMPLE 6.11,PAGE NUMBER 285-286"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "from __future__ import division\n",

-      "from math import pi\n",

-      "\n",

-      "# Variable Declaration\n",

-      "\n",

-      "a = 0.5  # radius of loop antenna in m\n",

-      "f = 0.9  # frequency in MHz\n",

-      "f = 0.9*10**6  # frequency in Hz\n",

-      "c = 3*10**8  # speed of light in m/s\n",

-      "\n",

-      "#calculation\n",

-      "\n",

-      "lamda = c/f  # wavelength in m\n",

-      "k = (2*pi*a)/lamda  # constant\n",

-      "\n",

-      "#Results\n",

-      "\n",

-      "print \"the value of k is:\",round(k,2)\n",

-      "print \"since,k<1/3\"\n",

-      "print \"So Directivity of loop antenna is D = 1.5\"\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "the value of k is: 0.01\n",

-        "since,k<1/3\n",

-        "So Directivity of loop antenna is D = 1.5\n"

-       ]

-      }

-     ],

-     "prompt_number": 11

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "EXAMPLE 6.13,PAGE NUMBER 286"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "from sympy import Symbol\n",

-      "\n",

-      "#variable declaration and calculation\n",

-      "\n",

-      "Lm = Symbol('Lm')  # defining Lm as lambda\n",

-      "d = 1.5*Lm  # diameter of antenna in m\n",

-      "a = d/2  # radius of antenna in m\n",

-      "Rr = 3720*(a/Lm)  # radiation resistance of loop antenna in ohm\n",

-      "D = 4.25*(a/Lm) # Directivity of the loop antenna\n",

-      "\n",

-      "#results\n",

-      "\n",

-      "print \"radiation resistance of the loop antenna is:\",round(Rr,0),\"ohm\"\n",

-      "print \"Directivity of the loop antenna is:\",round(D,4)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "radiation resistance of the loop antenna is: 2790.0 ohm\n",

-        "Directivity of the loop antenna is: 3.1875\n"

-       ]

-      }

-     ],

-     "prompt_number": 12

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "EXAMPLE 6.14,PAGE NUMBER 287"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "from math import sqrt,pi\n",

-      "from sympy import Symbol\n",

-      "\n",

-      "#Variable declaration\n",

-      "\n",

-      "Gp = 28  # power gain\n",

-      "\n",

-      "#calculations\n",

-      "\n",

-      "Lm = Symbol('Lm')  # defining Lm as lamda\n",

-      "d = Lm/2           # length of dipole\n",

-      "\n",

-      "#formula : Gp = 4*(L/lamda)\n",

-      "\n",

-      "L = Gp*Lm/4  # array length\n",

-      "N = 7*2      # Number of elements in the array when spaced at lamda/2\n",

-      "\n",

-      "# formula : B.W = 2*sqrt((2*/N)*(lamda/d))\n",

-      "\n",

-      "BW = 2*sqrt(2*Lm/(N*d))  # null-to-null beam width in radians\n",

-      "BW_d = BW*180/pi         # null-to-null beam width in degrees\n",

-      "\n",

-      "#Results\n",

-      "\n",

-      "print \"Number of elements in the array when spaced at lamda/2 are:\",N\n",

-      "print \"array length(where Lm is wavelength in m) is:\",L,\"m\"\n",

-      "print \"null-to-null beam width is:\",round(BW_d,1),\"degrees\"\n",

-      "\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Number of elements in the array when spaced at lamda/2 are: 14\n",

-        "array length(where Lm is wavelength in m) is: 7*Lm m\n",

-        "null-to-null beam width is: 61.3 degrees\n"

-       ]

-      }

-     ],

-     "prompt_number": 13

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "EXAMPLE 6.15,PAGE NUMBER 287"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "from __future__ import division\n",

-      "from math import pi,sqrt\n",

-      "\n",

-      "\n",

-      "# Variable Declaration\n",

-      "\n",

-      "S = 0.05        # spacing in m\n",

-      "Dh = 0.1        # diameter of helical antenna in m\n",

-      "N = 20          # number of turns\n",

-      "f = 1000        # frequency in MHz\n",

-      "f = 1000*10**6  # frequency in MHz\n",

-      "c = 3*10**8     # speed of light in m/s\n",

-      "\n",

-      "\n",

-      "#calculation\n",

-      "\n",

-      "\n",

-      "lamda = c/f     # wavelength in m\n",

-      "C = pi*Dh       # circumfrence of helix in m\n",

-      "La = N*S        # axial legth in m\n",

-      "phi_not = (115*(lamda**(3/2))/(C*sqrt(La)))   # B.W.F.N., null-to-null beamwidth of main beam in Degreess\n",

-      "phi = (52*lamda**(3/2)/(C*sqrt(La)))          # H.P.B.W, half power beamwidth in Degreess\n",

-      "D = (15*N*C**2*S/(lamda)**3)                  # Directivity\n",

-      "\n",

-      "#Results\n",

-      "\n",

-      "print \"B.W.F.N., null-to-null beamwidth of main beam is:\",round(phi_not,1),\"degrees\"\n",

-      "print \"H.P.B.W, half power beamwidth is:\",round(phi,1),\"degrees\"\n",

-      "print \"Directivity is:\",round(D,2)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "B.W.F.N., null-to-null beamwidth of main beam is: 60.1 degrees\n",

-        "H.P.B.W, half power beamwidth is: 27.2 degrees\n",

-        "Directivity is: 54.83\n"

-       ]

-      }

-     ],

-     "prompt_number": 14

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/TestContribution/abhisheksharma_1.ipynb b/TestContribution/abhisheksharma_1.ipynb
deleted file mode 100755
index e09e86cb..00000000
--- a/TestContribution/abhisheksharma_1.ipynb
+++ /dev/null
@@ -1,946 +0,0 @@
-{

- "metadata": {

-  "name": "",

-  "signature": "sha256:54ccd26f8e7172369b740037968be286180ddfff5f2fc10ebe6be83fc34647f9"

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "HF,VHF AND UHF ANTENNAS (CHAPTER 6)"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "EXAMPLE 6.1,PAGE NUMBER 278 "

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "from math import pi,sin\n",

-      "\n",

-      "# Variable Declaration\n",

-      "\n",

-      "f = 30        # frequency in MHz\n",

-      "f = 30*10**6  # frequency in Hz\n",

-      "c = 3*10**8   # speed of light in m/s\n",

-      "lamda = c/f   # wavelength in meter\n",

-      "Delta = 30    # angle of elevation in Degrees\n",

-      "\n",

-      "#calculation\n",

-      "\n",

-      "H = lamda/(4 * sin(Delta*pi/180))     # Rhombic height in m\n",

-      "l = lamda/(2 * sin(Delta*pi/180) **2) # wire length in m\n",

-      "phi = 90-Delta # tilt angle in Degrees\n",

-      "\n",

-      "#Results\n",

-      "\n",

-      "print \"Rhombic height is:\",round(H,2),\"meter\"\n",

-      "print \"Tilt angle is:\",round(phi,2),\"degrees\"\n",

-      "print \"length of wire is:\",round(l,2),\"meter\"\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Rhombic height is: 5.0 meter\n",

-        "Tilt angle is: 60.0 degrees\n",

-        "length of wire is: 20.0 meter\n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "EXAMPLE 6.2,PAGE NUMBER 278"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "from math import pi,sin\n",

-      "\n",

-      "\n",

-      "# Variable Declaration\n",

-      "\n",

-      "f = 20        # frequency in MHz\n",

-      "f = 20*10**6  # frequency in Hz\n",

-      "c = 3*10**8   # speed of light in m/s\n",

-      "lamda = c/f   # wavelength in meter\n",

-      "\n",

-      "#calculation\n",

-      "\n",

-      "Delta = 10    # angle of elevation in Degrees\n",

-      "H = lamda/(4 * sin(Delta*pi/180))     # Rhombic height in m\n",

-      "l = lamda/(2 * sin(Delta*pi/180) **2) # wire length in m\n",

-      "phi = 90-Delta # tilt angle in Degrees\n",

-      "\n",

-      "#Results\n",

-      "\n",

-      "print \"Rhombic height is:\",round(H,3),\"meter\"\n",

-      "print \"Tilt angle is:\",round(phi,2),\"degrees\"\n",

-      "print \"length of wire is:\",round(l,3),\"meter\"\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Rhombic height is: 21.595 meter\n",

-        "Tilt angle is: 80.0 degrees\n",

-        "length of wire is: 248.726 meter\n"

-       ]

-      }

-     ],

-     "prompt_number": 2

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "EXAMPLE 6.3,PAGE NUMBER 279-281"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "from math import pi,sin,cos\n",

-      "\n",

-      "\n",

-      "\n",

-      "# Variable Declaration\n",

-      "\n",

-      "f = 30        # frequency in MHz\n",

-      "f = 30*10**6  # frequency in Hz\n",

-      "c = 3*10**8   # speed of light in m/s\n",

-      "lamda = c/f   # wavelength in meter\n",

-      "\n",

-      "#calculation and results:\n",

-      "\n",

-      "\n",

-      "\n",

-      "print \"for Delta = 10 degrees\"\n",

-      "\n",

-      "\n",

-      "Delta1 = 10    # angle of elevation in Degrees\n",

-      "H1 = lamda/(4 * sin(Delta1*pi/180))     # Rhombic height in m\n",

-      "l1 = lamda/(2 * sin(Delta1*pi/180) **2) # wire length in m\n",

-      "phi1 = 90-Delta1 # tilt angle in Degrees\n",

-      "print \"Rhombic height is:\",round(H1,3),\"meter\"\n",

-      "print \"Tilt angle is:\",round(phi1,2),\"degrees\"\n",

-      "print \"length of wire is:\",round(l1,2),\"meter\"\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "print \"for Delta = 15 degrees\"\n",

-      "\n",

-      "\n",

-      "Delta2 = 15    # angle of elevation in Degrees\n",

-      "H2 = lamda/(4 * sin(Delta2*pi/180))     # Rhombic height in m\n",

-      "l2 = lamda/(2 * sin(Delta2*pi/180) **2) # wire length in m\n",

-      "phi2 = 90-Delta2 # tilt angle in Degrees\n",

-      "print \"Rhombic height is:\",round(H2,3),\"meter\"\n",

-      "print \"Tilt angle is:\",round(phi2,2),\"degrees\"\n",

-      "print \"length of wire is:\",round(l2,2),\"meter\"\n",

-      "\n",

-      "\n",

-      "\n",

-      "print \"for Delta = 20 degrees\"\n",

-      "\n",

-      "\n",

-      "Delta3 = 20    # angle of elevation in Degrees\n",

-      "H3 = lamda/(4 * sin(Delta3*pi/180))     # Rhombic height in m\n",

-      "l3 = lamda/(2 * sin(Delta3*pi/180) **2) # wire length in m\n",

-      "phi3 = 90-Delta3 # tilt angle in Degrees\n",

-      "print \"Rhombic height is:\",round(H3,3),\"meter\"\n",

-      "print \"Tilt angle is:\",round(phi3,2),\"degrees\"\n",

-      "print \"length of wire is:\",round(l3,2),\"meter\"\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "print \"for Delta = 25 degrees\"\n",

-      "\n",

-      "\n",

-      "Delta4 = 25    # angle of elevation in Degrees\n",

-      "H4 = lamda/(4 * sin(Delta4*pi/180))     # Rhombic height in m\n",

-      "l4 = lamda/(2 * sin(Delta4*pi/180) **2) # wire length in m\n",

-      "phi4 = 90-Delta4 # tilt angle in Degrees\n",

-      "print \"Rhombic height is:\",round(H4,3),\"meter\"\n",

-      "print \"Tilt angle is:\",round(phi4,2),\"degrees\"\n",

-      "print \"length of wire is:\",round(l4,2),\"meter\"\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "print \"for Delta = 30 degrees\"\n",

-      "\n",

-      "\n",

-      "Delta5 = 30    # angle of elevation in Degrees\n",

-      "H5 = lamda/(4 * sin(Delta5*pi/180))     # Rhombic height in m\n",

-      "l5 = lamda/(2 * sin(Delta5*pi/180) **2) # wire length in m\n",

-      "phi5 = 90-Delta5 # tilt angle in Degrees\n",

-      "print \"Rhombic height is:\",round(H5,3),\"meter\"\n",

-      "print \"Tilt angle is:\",round(phi5,2),\"degrees\"\n",

-      "print \"length of wire is:\",round(l5,2),\"meter\"\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "print \"for Delta = 35 degrees\"\n",

-      "\n",

-      "\n",

-      "Delta6 = 35    # angle of elevation in Degrees\n",

-      "H6 = lamda/(4 * sin(Delta6*pi/180))     # Rhombic height in m\n",

-      "l6 = lamda/(2 * sin(Delta6*pi/180) **2) # wire length in m\n",

-      "phi6 = 90-Delta6 # tilt angle in Degrees\n",

-      "print \"Rhombic height is:\",round(H6,3),\"meter\"\n",

-      "print \"Tilt angle is:\",round(phi6,2),\"degrees\"\n",

-      "print \"length of wire is:\",round(l6,2),\"meter\"\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "print \"for Delta = 40 degrees\"\n",

-      "\n",

-      "\n",

-      "Delta7 = 40    # angle of elevation in Degrees\n",

-      "H7 = lamda/(4 * sin(Delta7*pi/180))     # Rhombic height in m\n",

-      "l7 = lamda/(2 * sin(Delta7*pi/180) **2) # wire length in m\n",

-      "phi7 = 90-Delta7 # tilt angle in Degrees\n",

-      "print \"Rhombic height is:\",round(H7,3),\"meter\"\n",

-      "print \"Tilt angle is:\",round(phi7,2),\"degrees\"\n",

-      "print \"length of wire is:\",round(l7,2),\"meter\"\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for Delta = 10 degrees\n",

-        "Rhombic height is: 14.397 meter\n",

-        "Tilt angle is: 80.0 degrees\n",

-        "length of wire is: 165.82 meter\n",

-        "for Delta = 15 degrees\n",

-        "Rhombic height is: 9.659 meter\n",

-        "Tilt angle is: 75.0 degrees\n",

-        "length of wire is: 74.64 meter\n",

-        "for Delta = 20 degrees\n",

-        "Rhombic height is: 7.31 meter\n",

-        "Tilt angle is: 70.0 degrees\n",

-        "length of wire is: 42.74 meter\n",

-        "for Delta = 25 degrees\n",

-        "Rhombic height is: 5.916 meter\n",

-        "Tilt angle is: 65.0 degrees\n",

-        "length of wire is: 27.99 meter\n",

-        "for Delta = 30 degrees\n",

-        "Rhombic height is: 5.0 meter\n",

-        "Tilt angle is: 60.0 degrees\n",

-        "length of wire is: 20.0 meter\n",

-        "for Delta = 35 degrees\n",

-        "Rhombic height is: 4.359 meter\n",

-        "Tilt angle is: 55.0 degrees\n",

-        "length of wire is: 15.2 meter\n",

-        "for Delta = 40 degrees\n",

-        "Rhombic height is: 3.889 meter\n",

-        "Tilt angle is: 50.0 degrees\n",

-        "length of wire is: 12.1 meter\n"

-       ]

-      }

-     ],

-     "prompt_number": 3

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "EXAMPLE 6.4,PAGE NUMBER 281"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "from math import pi,sin,cos\n",

-      "\n",

-      "\n",

-      "\n",

-      "# Variable Declaration\n",

-      "\n",

-      "f = 30        # frequency in MHz\n",

-      "f = 30*10**6  # frequency in Hz\n",

-      "c = 3*10**8   # speed of light in m/s\n",

-      "lamda = c/f   # wavelength in meter\n",

-      "Delta = 30    # angle of elevation in Degrees\n",

-      "\n",

-      "#calculation\n",

-      "\n",

-      "k = 0.74      # constant\n",

-      "H = lamda/(4 * sin(Delta*pi/180))     # Rhombic height in m\n",

-      "l = lamda/(2 * sin(Delta*pi/180) **2)*k # wire length in m\n",

-      "phi = 90-Delta # tilt angle in Degrees\n",

-      "\n",

-      "#Results\n",

-      "\n",

-      "print \"Rhombic height is:\",round(H,2),\"meter\"\n",

-      "print \"Tilt angle is:\",round(phi,2),\"degrees\"\n",

-      "print \"length of wire is:\",round(l,2),\"meter\"\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Rhombic height is: 5.0 meter\n",

-        "Tilt angle is: 60.0 degrees\n",

-        "length of wire is: 14.8 meter\n"

-       ]

-      }

-     ],

-     "prompt_number": 4

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "EXAMPLE 6.5,PAGE NUMBER 282"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "from math import pi,sin\n",

-      "\n",

-      "\n",

-      "# Variable Declaration\n",

-      "\n",

-      "f = 20        # frequency in MHz\n",

-      "f = 20*10**6  # frequency in Hz\n",

-      "c = 3*10**8   # speed of light in m/s\n",

-      "lamda = c/f   # wavelength in meter\n",

-      "Delta = 20    # angle of elevation in Degrees\n",

-      "k = 0.74      # constant\n",

-      "\n",

-      "#calculation\n",

-      "\n",

-      "H = lamda/(4 * sin(Delta*pi/180))     # Rhombic height in m\n",

-      "l = lamda/(2 * sin(Delta*pi/180) **2)*k # wire length in m\n",

-      "phi = 90-Delta # tilt angle in Degrees\n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "\n",

-      "\n",

-      "print \"Rhombic height is:\",round(H,2),\"meter\"\n",

-      "print \"Tilt angle is:\",round(phi,2),\"degrees\"\n",

-      "print \"length of wire is:\",round(l,2),\"meter\"\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Rhombic height is: 10.96 meter\n",

-        "Tilt angle is: 70.0 degrees\n",

-        "length of wire is: 47.44 meter\n"

-       ]

-      }

-     ],

-     "prompt_number": 5

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "EXAMPLE 6.6,PAGE NUMBER 282"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "from __future__ import division\n",

-      "\n",

-      "\n",

-      "\n",

-      "# Variable Declaration\n",

-      "\n",

-      "\n",

-      "f_MHz = 172        # frequency in MHz\n",

-      "c = 3*10**8        # speed of light in m/s\n",

-      "\n",

-      "#calculation\n",

-      "\n",

-      "lamda = c/f_MHz    # wavelength in m\n",

-      "La = 478/f_MHz     # length of driven element in feet\n",

-      "Lr = 492/f_MHz     # length of reflector in feet\n",

-      "Ld = 461.5/f_MHz   # length of director in feet\n",

-      "S = 142/f_MHz      # element spacing in feet\n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "\n",

-      "\n",

-      "print \"length of driven element is:\", round(La,2),\"feet\"\n",

-      "print \"length of reflector is:\", round(Lr,2),\"feet\"\n",

-      "print \"length of director is:\", round(Ld,3),\"feet\"\n",

-      "print \"element spacing is:\",round(S,3),\"feet\"\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "length of driven element is: 2.78 feet\n",

-        "length of reflector is: 2.86 feet\n",

-        "length of director is: 2.683 feet\n",

-        "element spacing is: 0.826 feet\n"

-       ]

-      }

-     ],

-     "prompt_number": 6

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "EXAMPLE 6.7,PAGE NUMBER 283"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "from __future__ import division\n",

-      "\n",

-      "# Variable Declaration\n",

-      "\n",

-      "\n",

-      "G = 12        # required gain in dB\n",

-      "f = 200       # frequency in MHz \n",

-      "f = 200*10**6  # frequency in Hz\n",

-      "c = 3*10**8    # speed of light in m/s\n",

-      "\n",

-      "#calculations\n",

-      "\n",

-      "\n",

-      "lamda = c/f   # wavelength in m\n",

-      "La = 0.46*lamda   # length of driven element in m    (note: in book La is given 0.416*lamda misprint)\n",

-      "Lr = 0.475*lamda  # length of reflector in m\n",

-      "Ld1 = 0.44*lamda  # length of director1 in m\n",

-      "Ld2 = 0.44*lamda  # length of director2 in m\n",

-      "Ld3 = 0.43*lamda  # length of director3 in m\n",

-      "Ld4 = 0.40*lamda  # length of director4 in m\n",

-      "SL = 0.25*lamda   # spacing between reflector and driver in m\n",

-      "Sd = 0.31*lamda   # spacing director and driving element in m\n",

-      "d = 0.01*lamda    # diameter of elements in m\n",

-      "l = 1.5*lamda     # length of array in m\n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "\n",

-      "\n",

-      "print \"length of driven element is:\" ,round(La,2),\"m\"\n",

-      "print \"length of reflector is:\",round(Lr,4),\"m\"\n",

-      "print \"length of director1 is:\",round(Ld1,2),\"m\"\n",

-      "print \"length of director2 is:\",round(Ld2,2),\"m\"\n",

-      "print \"length of director3 is:\",round(Ld3,3),\"m\"\n",

-      "print \"length of director4 is:\",round(Ld4,2),\"m\"\n",

-      "print \"spacing between reflector and driver is:\",round(SL,3),\"m\"\n",

-      "print \"spacing director and driving element is:\",round(Sd,3),\"m\"\n",

-      "print \"diameter of elements is:\",round(d,3),\"m\"\n",

-      "print \"length of array is:\",round(l,2),\"m\"\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "length of driven element is: 0.69 m\n",

-        "length of reflector is: 0.7125 m\n",

-        "length of director1 is: 0.66 m\n",

-        "length of director2 is: 0.66 m\n",

-        "length of director3 is: 0.645 m\n",

-        "length of director4 is: 0.6 m\n",

-        "spacing between reflector and driver is: 0.375 m\n",

-        "spacing director and driving element is: 0.465 m\n",

-        "diameter of elements is: 0.015 m\n",

-        "length of array is: 2.25 m\n"

-       ]

-      }

-     ],

-     "prompt_number": 7

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "EXAMPLE 6.8,PAGE NUMBER 283"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "from __future__ import division\n",

-      "from math import atan\n",

-      "\n",

-      "\n",

-      "# Variable Declaration\n",

-      "\n",

-      "\n",

-      "G = 9             # required gain in dB\n",

-      "f_l = 125         # lowest frequency in MHz\n",

-      "f_l = 125*10**6   # lowest frequency in Hz\n",

-      "f_h = 500         # highest frequency in MHz\n",

-      "f_h = 500*10**6   # lowest frequency in Hz\n",

-      "c = 3*10**8       # speed of light in m/s\n",

-      "tau = 0.861       # scaling factor\n",

-      "sigma = 0.162     # spacing factor\n",

-      "\n",

-      "\n",

-      "#calculation\n",

-      "\n",

-      "\n",

-      "lamda_l = c/f_l  # longest wavelength in m\n",

-      "lamda_s = c/f_h  # shortest wavelength in m\n",

-      "alpha = 2*atan((1-tau)/(4*sigma))  # wedge angle in Degrees\n",

-      "L1 =  lamda_l/2  # in m\n",

-      "L2 = tau*L1  # in m\n",

-      "L3 = tau*L2  # in m\n",

-      "L4 = tau*L3  # in m\n",

-      "L5 = tau*L4  # in m\n",

-      "L6 = tau*L5  # in m\n",

-      "L7 = tau*L6  # in m\n",

-      "L8 = tau*L7  # in m\n",

-      "L9 = tau*L8  # in m\n",

-      "L10 = tau*L9  # in m\n",

-      "L11 = tau*L10  # in m\n",

-      "\n",

-      "# element spacing relation\n",

-      "#formula : sn = 2*sigma*Ln\n",

-      "\n",

-      "\n",

-      "S1 = 2*sigma*L1  # in m\n",

-      "S2 = 2*sigma*L2  # in m\n",

-      "S3 = 2*sigma*L3  # in m\n",

-      "S4 = 2*sigma*L4  # in m\n",

-      "S5 = 2*sigma*L5  # in m\n",

-      "S6 = 2*sigma*L6  # in m\n",

-      "S7 = 2*sigma*L7  # in m\n",

-      "S8 = 2*sigma*L8  # in m\n",

-      "S9 = 2*sigma*L9  # in m\n",

-      "S10 = 2*sigma*L10  # in m\n",

-      "S11 = 2*sigma*L11  # in m\n",

-      "\n",

-      "\n",

-      "\n",

-      "#results\n",

-      "\n",

-      "\n",

-      "print(\"designing of log-periodic antenna:\")\n",

-      "\n",

-      "print \"L1 is:\",round(L1,4),\"m\"\n",

-      "print \"L2 is:\",round(L2,4),\"m\"\n",

-      "print \"L3 is:\",round(L3,4),\"m\"\n",

-      "print \"L4 is:\",round(L4,4),\"m\"\n",

-      "print \"L5 is:\",round(L5,4),\"m\"\n",

-      "print \"L6 is:\",round(L6,4),\"m\"\n",

-      "print \"L7 is:\",round(L7,4),\"m\"\n",

-      "print \"L8 is:\",round(L8,4),\"m\"\n",

-      "print \"L9 is:\",round(L9,4),\"m\"\n",

-      "print \"L10 is:\",round(L10,4),\"m\"\n",

-      "print \"L11 is:\",round(L11,4),\"m\"\n",

-      "\n",

-      "print \"elements spacing relation:\"\n",

-      "\n",

-      "print \"S1 is:\",round(S1,4),\"m\"\n",

-      "print \"S2 is:\",round(S2,4),\"m\"\n",

-      "print \"S3 is:\",round(S3,4),\"m\"\n",

-      "print \"S4 is:\",round(S4,4),\"m\"\n",

-      "print \"S5 is:\",round(S5,4),\"m\"\n",

-      "print \"S6 is:\",round(S6,4),\"m\"\n",

-      "print \"S7 is:\",round(S7,4),\"m\"\n",

-      "print \"S8 is:\",round(S8,4),\"m\"\n",

-      "print \"S9 is:\",round(S9,4),\"m\"\n",

-      "print \"S10 is:\",round(S10,4),\"m\"\n",

-      "print \"S11 is:\",round(S11,4),\"m\"\n",

-      "\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "designing of log-periodic antenna:\n",

-        "L1 is: 1.2 m\n",

-        "L2 is: 1.0332 m\n",

-        "L3 is: 0.8896 m\n",

-        "L4 is: 0.7659 m\n",

-        "L5 is: 0.6595 m\n",

-        "L6 is: 0.5678 m\n",

-        "L7 is: 0.4889 m\n",

-        "L8 is: 0.4209 m\n",

-        "L9 is: 0.3624 m\n",

-        "L10 is: 0.312 m\n",

-        "L11 is: 0.2687 m\n",

-        "elements spacing relation:\n",

-        "S1 is: 0.3888 m\n",

-        "S2 is: 0.3348 m\n",

-        "S3 is: 0.2882 m\n",

-        "S4 is: 0.2482 m\n",

-        "S5 is: 0.2137 m\n",

-        "S6 is: 0.184 m\n",

-        "S7 is: 0.1584 m\n",

-        "S8 is: 0.1364 m\n",

-        "S9 is: 0.1174 m\n",

-        "S10 is: 0.1011 m\n",

-        "S11 is: 0.087 m\n"

-       ]

-      }

-     ],

-     "prompt_number": 8

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "EXAMPLE 6.9,PAGE NUMBER 285"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "from math import pi,cos,sqrt\n",

-      "\n",

-      "\n",

-      "# Variable Declaration\n",

-      "\n",

-      "E_rms = 10  # electric field in mV/m\n",

-      "E_rms = 10*10 **-3  # electric field in V/m\n",

-      "f = 2  # frequency in MHz\n",

-      "f = 2*10 **6  # frequency in Hz\n",

-      "N = 10  # number of turns\n",

-      "phi = 0  # angle between the plane of loop and direction of incident wave in Degrees\n",

-      "S = 1.4  # area of loop antenna in m **2\n",

-      "c = 3*10 **8  # speed of light in m/s\n",

-      "\n",

-      "#calculation\n",

-      "\n",

-      "lamda = c/f  # wavelength in m\n",

-      "E_max = sqrt(2)*E_rms  # electric field in V/m\n",

-      "V_rms = (2*pi*E_max*S*N/lamda)*cos(phi)  # induced voltage\n",

-      "\n",

-      "#Result\n",

-      "\n",

-      "print \"induced voltage is:\",round(V_rms*1000,2),\"mV\"\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "induced voltage is: 8.29 mV\n"

-       ]

-      }

-     ],

-     "prompt_number": 9

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "EXAMPLE 6.10,PAGE NUMBER 285"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "\n",

-      "# Variable Declaration\n",

-      "\n",

-      "\n",

-      "D = 0.5  # diameter of loop antenna in m\n",

-      "a = D/2  # radius of loop antenna in m\n",

-      "f = 1  # frequency in MHz\n",

-      "f = 1*10**6  # frequency in Hz\n",

-      "c = 3*10**8  # speed of light in m/s\n",

-      "\n",

-      "#calculation\n",

-      "\n",

-      "lamda = c/f  # wavelength in m\n",

-      "Rr = 3720*(a/lamda)  # radiation resistance of loop antenna in ohm\n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "\n",

-      "print \"radiation resistance of loop antenna is:\",Rr,\"ohm\"\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "radiation resistance of loop antenna is: 3.1 ohm\n"

-       ]

-      }

-     ],

-     "prompt_number": 10

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "EXAMPLE 6.11,PAGE NUMBER 285-286"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "from __future__ import division\n",

-      "from math import pi\n",

-      "\n",

-      "# Variable Declaration\n",

-      "\n",

-      "a = 0.5  # radius of loop antenna in m\n",

-      "f = 0.9  # frequency in MHz\n",

-      "f = 0.9*10**6  # frequency in Hz\n",

-      "c = 3*10**8  # speed of light in m/s\n",

-      "\n",

-      "#calculation\n",

-      "\n",

-      "lamda = c/f  # wavelength in m\n",

-      "k = (2*pi*a)/lamda  # constant\n",

-      "\n",

-      "#Results\n",

-      "\n",

-      "print \"the value of k is:\",round(k,2)\n",

-      "print \"since,k<1/3\"\n",

-      "print \"So Directivity of loop antenna is D = 1.5\"\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "the value of k is: 0.01\n",

-        "since,k<1/3\n",

-        "So Directivity of loop antenna is D = 1.5\n"

-       ]

-      }

-     ],

-     "prompt_number": 11

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "EXAMPLE 6.13,PAGE NUMBER 286"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "from sympy import Symbol\n",

-      "\n",

-      "#variable declaration and calculation\n",

-      "\n",

-      "Lm = Symbol('Lm')  # defining Lm as lambda\n",

-      "d = 1.5*Lm  # diameter of antenna in m\n",

-      "a = d/2  # radius of antenna in m\n",

-      "Rr = 3720*(a/Lm)  # radiation resistance of loop antenna in ohm\n",

-      "D = 4.25*(a/Lm) # Directivity of the loop antenna\n",

-      "\n",

-      "#results\n",

-      "\n",

-      "print \"radiation resistance of the loop antenna is:\",round(Rr,0),\"ohm\"\n",

-      "print \"Directivity of the loop antenna is:\",round(D,4)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "radiation resistance of the loop antenna is: 2790.0 ohm\n",

-        "Directivity of the loop antenna is: 3.1875\n"

-       ]

-      }

-     ],

-     "prompt_number": 12

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "EXAMPLE 6.14,PAGE NUMBER 287"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "from math import sqrt,pi\n",

-      "from sympy import Symbol\n",

-      "\n",

-      "#Variable declaration\n",

-      "\n",

-      "Gp = 28  # power gain\n",

-      "\n",

-      "#calculations\n",

-      "\n",

-      "Lm = Symbol('Lm')  # defining Lm as lamda\n",

-      "d = Lm/2           # length of dipole\n",

-      "\n",

-      "#formula : Gp = 4*(L/lamda)\n",

-      "\n",

-      "L = Gp*Lm/4  # array length\n",

-      "N = 7*2      # Number of elements in the array when spaced at lamda/2\n",

-      "\n",

-      "# formula : B.W = 2*sqrt((2*/N)*(lamda/d))\n",

-      "\n",

-      "BW = 2*sqrt(2*Lm/(N*d))  # null-to-null beam width in radians\n",

-      "BW_d = BW*180/pi         # null-to-null beam width in degrees\n",

-      "\n",

-      "#Results\n",

-      "\n",

-      "print \"Number of elements in the array when spaced at lamda/2 are:\",N\n",

-      "print \"array length(where Lm is wavelength in m) is:\",L,\"m\"\n",

-      "print \"null-to-null beam width is:\",round(BW_d,1),\"degrees\"\n",

-      "\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Number of elements in the array when spaced at lamda/2 are: 14\n",

-        "array length(where Lm is wavelength in m) is: 7*Lm m\n",

-        "null-to-null beam width is: 61.3 degrees\n"

-       ]

-      }

-     ],

-     "prompt_number": 13

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "EXAMPLE 6.15,PAGE NUMBER 287"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "from __future__ import division\n",

-      "from math import pi,sqrt\n",

-      "\n",

-      "\n",

-      "# Variable Declaration\n",

-      "\n",

-      "S = 0.05        # spacing in m\n",

-      "Dh = 0.1        # diameter of helical antenna in m\n",

-      "N = 20          # number of turns\n",

-      "f = 1000        # frequency in MHz\n",

-      "f = 1000*10**6  # frequency in MHz\n",

-      "c = 3*10**8     # speed of light in m/s\n",

-      "\n",

-      "\n",

-      "#calculation\n",

-      "\n",

-      "\n",

-      "lamda = c/f     # wavelength in m\n",

-      "C = pi*Dh       # circumfrence of helix in m\n",

-      "La = N*S        # axial legth in m\n",

-      "phi_not = (115*(lamda**(3/2))/(C*sqrt(La)))   # B.W.F.N., null-to-null beamwidth of main beam in Degreess\n",

-      "phi = (52*lamda**(3/2)/(C*sqrt(La)))          # H.P.B.W, half power beamwidth in Degreess\n",

-      "D = (15*N*C**2*S/(lamda)**3)                  # Directivity\n",

-      "\n",

-      "#Results\n",

-      "\n",

-      "print \"B.W.F.N., null-to-null beamwidth of main beam is:\",round(phi_not,1),\"degrees\"\n",

-      "print \"H.P.B.W, half power beamwidth is:\",round(phi,1),\"degrees\"\n",

-      "print \"Directivity is:\",round(D,2)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "B.W.F.N., null-to-null beamwidth of main beam is: 60.1 degrees\n",

-        "H.P.B.W, half power beamwidth is: 27.2 degrees\n",

-        "Directivity is: 54.83\n"

-       ]

-      }

-     ],

-     "prompt_number": 14

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/TestContribution/abhisheksharma_2.ipynb b/TestContribution/abhisheksharma_2.ipynb
deleted file mode 100755
index e09e86cb..00000000
--- a/TestContribution/abhisheksharma_2.ipynb
+++ /dev/null
@@ -1,946 +0,0 @@
-{

- "metadata": {

-  "name": "",

-  "signature": "sha256:54ccd26f8e7172369b740037968be286180ddfff5f2fc10ebe6be83fc34647f9"

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "HF,VHF AND UHF ANTENNAS (CHAPTER 6)"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "EXAMPLE 6.1,PAGE NUMBER 278 "

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "from math import pi,sin\n",

-      "\n",

-      "# Variable Declaration\n",

-      "\n",

-      "f = 30        # frequency in MHz\n",

-      "f = 30*10**6  # frequency in Hz\n",

-      "c = 3*10**8   # speed of light in m/s\n",

-      "lamda = c/f   # wavelength in meter\n",

-      "Delta = 30    # angle of elevation in Degrees\n",

-      "\n",

-      "#calculation\n",

-      "\n",

-      "H = lamda/(4 * sin(Delta*pi/180))     # Rhombic height in m\n",

-      "l = lamda/(2 * sin(Delta*pi/180) **2) # wire length in m\n",

-      "phi = 90-Delta # tilt angle in Degrees\n",

-      "\n",

-      "#Results\n",

-      "\n",

-      "print \"Rhombic height is:\",round(H,2),\"meter\"\n",

-      "print \"Tilt angle is:\",round(phi,2),\"degrees\"\n",

-      "print \"length of wire is:\",round(l,2),\"meter\"\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Rhombic height is: 5.0 meter\n",

-        "Tilt angle is: 60.0 degrees\n",

-        "length of wire is: 20.0 meter\n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "EXAMPLE 6.2,PAGE NUMBER 278"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "from math import pi,sin\n",

-      "\n",

-      "\n",

-      "# Variable Declaration\n",

-      "\n",

-      "f = 20        # frequency in MHz\n",

-      "f = 20*10**6  # frequency in Hz\n",

-      "c = 3*10**8   # speed of light in m/s\n",

-      "lamda = c/f   # wavelength in meter\n",

-      "\n",

-      "#calculation\n",

-      "\n",

-      "Delta = 10    # angle of elevation in Degrees\n",

-      "H = lamda/(4 * sin(Delta*pi/180))     # Rhombic height in m\n",

-      "l = lamda/(2 * sin(Delta*pi/180) **2) # wire length in m\n",

-      "phi = 90-Delta # tilt angle in Degrees\n",

-      "\n",

-      "#Results\n",

-      "\n",

-      "print \"Rhombic height is:\",round(H,3),\"meter\"\n",

-      "print \"Tilt angle is:\",round(phi,2),\"degrees\"\n",

-      "print \"length of wire is:\",round(l,3),\"meter\"\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Rhombic height is: 21.595 meter\n",

-        "Tilt angle is: 80.0 degrees\n",

-        "length of wire is: 248.726 meter\n"

-       ]

-      }

-     ],

-     "prompt_number": 2

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "EXAMPLE 6.3,PAGE NUMBER 279-281"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "from math import pi,sin,cos\n",

-      "\n",

-      "\n",

-      "\n",

-      "# Variable Declaration\n",

-      "\n",

-      "f = 30        # frequency in MHz\n",

-      "f = 30*10**6  # frequency in Hz\n",

-      "c = 3*10**8   # speed of light in m/s\n",

-      "lamda = c/f   # wavelength in meter\n",

-      "\n",

-      "#calculation and results:\n",

-      "\n",

-      "\n",

-      "\n",

-      "print \"for Delta = 10 degrees\"\n",

-      "\n",

-      "\n",

-      "Delta1 = 10    # angle of elevation in Degrees\n",

-      "H1 = lamda/(4 * sin(Delta1*pi/180))     # Rhombic height in m\n",

-      "l1 = lamda/(2 * sin(Delta1*pi/180) **2) # wire length in m\n",

-      "phi1 = 90-Delta1 # tilt angle in Degrees\n",

-      "print \"Rhombic height is:\",round(H1,3),\"meter\"\n",

-      "print \"Tilt angle is:\",round(phi1,2),\"degrees\"\n",

-      "print \"length of wire is:\",round(l1,2),\"meter\"\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "print \"for Delta = 15 degrees\"\n",

-      "\n",

-      "\n",

-      "Delta2 = 15    # angle of elevation in Degrees\n",

-      "H2 = lamda/(4 * sin(Delta2*pi/180))     # Rhombic height in m\n",

-      "l2 = lamda/(2 * sin(Delta2*pi/180) **2) # wire length in m\n",

-      "phi2 = 90-Delta2 # tilt angle in Degrees\n",

-      "print \"Rhombic height is:\",round(H2,3),\"meter\"\n",

-      "print \"Tilt angle is:\",round(phi2,2),\"degrees\"\n",

-      "print \"length of wire is:\",round(l2,2),\"meter\"\n",

-      "\n",

-      "\n",

-      "\n",

-      "print \"for Delta = 20 degrees\"\n",

-      "\n",

-      "\n",

-      "Delta3 = 20    # angle of elevation in Degrees\n",

-      "H3 = lamda/(4 * sin(Delta3*pi/180))     # Rhombic height in m\n",

-      "l3 = lamda/(2 * sin(Delta3*pi/180) **2) # wire length in m\n",

-      "phi3 = 90-Delta3 # tilt angle in Degrees\n",

-      "print \"Rhombic height is:\",round(H3,3),\"meter\"\n",

-      "print \"Tilt angle is:\",round(phi3,2),\"degrees\"\n",

-      "print \"length of wire is:\",round(l3,2),\"meter\"\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "print \"for Delta = 25 degrees\"\n",

-      "\n",

-      "\n",

-      "Delta4 = 25    # angle of elevation in Degrees\n",

-      "H4 = lamda/(4 * sin(Delta4*pi/180))     # Rhombic height in m\n",

-      "l4 = lamda/(2 * sin(Delta4*pi/180) **2) # wire length in m\n",

-      "phi4 = 90-Delta4 # tilt angle in Degrees\n",

-      "print \"Rhombic height is:\",round(H4,3),\"meter\"\n",

-      "print \"Tilt angle is:\",round(phi4,2),\"degrees\"\n",

-      "print \"length of wire is:\",round(l4,2),\"meter\"\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "print \"for Delta = 30 degrees\"\n",

-      "\n",

-      "\n",

-      "Delta5 = 30    # angle of elevation in Degrees\n",

-      "H5 = lamda/(4 * sin(Delta5*pi/180))     # Rhombic height in m\n",

-      "l5 = lamda/(2 * sin(Delta5*pi/180) **2) # wire length in m\n",

-      "phi5 = 90-Delta5 # tilt angle in Degrees\n",

-      "print \"Rhombic height is:\",round(H5,3),\"meter\"\n",

-      "print \"Tilt angle is:\",round(phi5,2),\"degrees\"\n",

-      "print \"length of wire is:\",round(l5,2),\"meter\"\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "print \"for Delta = 35 degrees\"\n",

-      "\n",

-      "\n",

-      "Delta6 = 35    # angle of elevation in Degrees\n",

-      "H6 = lamda/(4 * sin(Delta6*pi/180))     # Rhombic height in m\n",

-      "l6 = lamda/(2 * sin(Delta6*pi/180) **2) # wire length in m\n",

-      "phi6 = 90-Delta6 # tilt angle in Degrees\n",

-      "print \"Rhombic height is:\",round(H6,3),\"meter\"\n",

-      "print \"Tilt angle is:\",round(phi6,2),\"degrees\"\n",

-      "print \"length of wire is:\",round(l6,2),\"meter\"\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "print \"for Delta = 40 degrees\"\n",

-      "\n",

-      "\n",

-      "Delta7 = 40    # angle of elevation in Degrees\n",

-      "H7 = lamda/(4 * sin(Delta7*pi/180))     # Rhombic height in m\n",

-      "l7 = lamda/(2 * sin(Delta7*pi/180) **2) # wire length in m\n",

-      "phi7 = 90-Delta7 # tilt angle in Degrees\n",

-      "print \"Rhombic height is:\",round(H7,3),\"meter\"\n",

-      "print \"Tilt angle is:\",round(phi7,2),\"degrees\"\n",

-      "print \"length of wire is:\",round(l7,2),\"meter\"\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for Delta = 10 degrees\n",

-        "Rhombic height is: 14.397 meter\n",

-        "Tilt angle is: 80.0 degrees\n",

-        "length of wire is: 165.82 meter\n",

-        "for Delta = 15 degrees\n",

-        "Rhombic height is: 9.659 meter\n",

-        "Tilt angle is: 75.0 degrees\n",

-        "length of wire is: 74.64 meter\n",

-        "for Delta = 20 degrees\n",

-        "Rhombic height is: 7.31 meter\n",

-        "Tilt angle is: 70.0 degrees\n",

-        "length of wire is: 42.74 meter\n",

-        "for Delta = 25 degrees\n",

-        "Rhombic height is: 5.916 meter\n",

-        "Tilt angle is: 65.0 degrees\n",

-        "length of wire is: 27.99 meter\n",

-        "for Delta = 30 degrees\n",

-        "Rhombic height is: 5.0 meter\n",

-        "Tilt angle is: 60.0 degrees\n",

-        "length of wire is: 20.0 meter\n",

-        "for Delta = 35 degrees\n",

-        "Rhombic height is: 4.359 meter\n",

-        "Tilt angle is: 55.0 degrees\n",

-        "length of wire is: 15.2 meter\n",

-        "for Delta = 40 degrees\n",

-        "Rhombic height is: 3.889 meter\n",

-        "Tilt angle is: 50.0 degrees\n",

-        "length of wire is: 12.1 meter\n"

-       ]

-      }

-     ],

-     "prompt_number": 3

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "EXAMPLE 6.4,PAGE NUMBER 281"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "from math import pi,sin,cos\n",

-      "\n",

-      "\n",

-      "\n",

-      "# Variable Declaration\n",

-      "\n",

-      "f = 30        # frequency in MHz\n",

-      "f = 30*10**6  # frequency in Hz\n",

-      "c = 3*10**8   # speed of light in m/s\n",

-      "lamda = c/f   # wavelength in meter\n",

-      "Delta = 30    # angle of elevation in Degrees\n",

-      "\n",

-      "#calculation\n",

-      "\n",

-      "k = 0.74      # constant\n",

-      "H = lamda/(4 * sin(Delta*pi/180))     # Rhombic height in m\n",

-      "l = lamda/(2 * sin(Delta*pi/180) **2)*k # wire length in m\n",

-      "phi = 90-Delta # tilt angle in Degrees\n",

-      "\n",

-      "#Results\n",

-      "\n",

-      "print \"Rhombic height is:\",round(H,2),\"meter\"\n",

-      "print \"Tilt angle is:\",round(phi,2),\"degrees\"\n",

-      "print \"length of wire is:\",round(l,2),\"meter\"\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Rhombic height is: 5.0 meter\n",

-        "Tilt angle is: 60.0 degrees\n",

-        "length of wire is: 14.8 meter\n"

-       ]

-      }

-     ],

-     "prompt_number": 4

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "EXAMPLE 6.5,PAGE NUMBER 282"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "from math import pi,sin\n",

-      "\n",

-      "\n",

-      "# Variable Declaration\n",

-      "\n",

-      "f = 20        # frequency in MHz\n",

-      "f = 20*10**6  # frequency in Hz\n",

-      "c = 3*10**8   # speed of light in m/s\n",

-      "lamda = c/f   # wavelength in meter\n",

-      "Delta = 20    # angle of elevation in Degrees\n",

-      "k = 0.74      # constant\n",

-      "\n",

-      "#calculation\n",

-      "\n",

-      "H = lamda/(4 * sin(Delta*pi/180))     # Rhombic height in m\n",

-      "l = lamda/(2 * sin(Delta*pi/180) **2)*k # wire length in m\n",

-      "phi = 90-Delta # tilt angle in Degrees\n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "\n",

-      "\n",

-      "print \"Rhombic height is:\",round(H,2),\"meter\"\n",

-      "print \"Tilt angle is:\",round(phi,2),\"degrees\"\n",

-      "print \"length of wire is:\",round(l,2),\"meter\"\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Rhombic height is: 10.96 meter\n",

-        "Tilt angle is: 70.0 degrees\n",

-        "length of wire is: 47.44 meter\n"

-       ]

-      }

-     ],

-     "prompt_number": 5

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "EXAMPLE 6.6,PAGE NUMBER 282"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "from __future__ import division\n",

-      "\n",

-      "\n",

-      "\n",

-      "# Variable Declaration\n",

-      "\n",

-      "\n",

-      "f_MHz = 172        # frequency in MHz\n",

-      "c = 3*10**8        # speed of light in m/s\n",

-      "\n",

-      "#calculation\n",

-      "\n",

-      "lamda = c/f_MHz    # wavelength in m\n",

-      "La = 478/f_MHz     # length of driven element in feet\n",

-      "Lr = 492/f_MHz     # length of reflector in feet\n",

-      "Ld = 461.5/f_MHz   # length of director in feet\n",

-      "S = 142/f_MHz      # element spacing in feet\n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "\n",

-      "\n",

-      "print \"length of driven element is:\", round(La,2),\"feet\"\n",

-      "print \"length of reflector is:\", round(Lr,2),\"feet\"\n",

-      "print \"length of director is:\", round(Ld,3),\"feet\"\n",

-      "print \"element spacing is:\",round(S,3),\"feet\"\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "length of driven element is: 2.78 feet\n",

-        "length of reflector is: 2.86 feet\n",

-        "length of director is: 2.683 feet\n",

-        "element spacing is: 0.826 feet\n"

-       ]

-      }

-     ],

-     "prompt_number": 6

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "EXAMPLE 6.7,PAGE NUMBER 283"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "from __future__ import division\n",

-      "\n",

-      "# Variable Declaration\n",

-      "\n",

-      "\n",

-      "G = 12        # required gain in dB\n",

-      "f = 200       # frequency in MHz \n",

-      "f = 200*10**6  # frequency in Hz\n",

-      "c = 3*10**8    # speed of light in m/s\n",

-      "\n",

-      "#calculations\n",

-      "\n",

-      "\n",

-      "lamda = c/f   # wavelength in m\n",

-      "La = 0.46*lamda   # length of driven element in m    (note: in book La is given 0.416*lamda misprint)\n",

-      "Lr = 0.475*lamda  # length of reflector in m\n",

-      "Ld1 = 0.44*lamda  # length of director1 in m\n",

-      "Ld2 = 0.44*lamda  # length of director2 in m\n",

-      "Ld3 = 0.43*lamda  # length of director3 in m\n",

-      "Ld4 = 0.40*lamda  # length of director4 in m\n",

-      "SL = 0.25*lamda   # spacing between reflector and driver in m\n",

-      "Sd = 0.31*lamda   # spacing director and driving element in m\n",

-      "d = 0.01*lamda    # diameter of elements in m\n",

-      "l = 1.5*lamda     # length of array in m\n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "\n",

-      "\n",

-      "print \"length of driven element is:\" ,round(La,2),\"m\"\n",

-      "print \"length of reflector is:\",round(Lr,4),\"m\"\n",

-      "print \"length of director1 is:\",round(Ld1,2),\"m\"\n",

-      "print \"length of director2 is:\",round(Ld2,2),\"m\"\n",

-      "print \"length of director3 is:\",round(Ld3,3),\"m\"\n",

-      "print \"length of director4 is:\",round(Ld4,2),\"m\"\n",

-      "print \"spacing between reflector and driver is:\",round(SL,3),\"m\"\n",

-      "print \"spacing director and driving element is:\",round(Sd,3),\"m\"\n",

-      "print \"diameter of elements is:\",round(d,3),\"m\"\n",

-      "print \"length of array is:\",round(l,2),\"m\"\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "length of driven element is: 0.69 m\n",

-        "length of reflector is: 0.7125 m\n",

-        "length of director1 is: 0.66 m\n",

-        "length of director2 is: 0.66 m\n",

-        "length of director3 is: 0.645 m\n",

-        "length of director4 is: 0.6 m\n",

-        "spacing between reflector and driver is: 0.375 m\n",

-        "spacing director and driving element is: 0.465 m\n",

-        "diameter of elements is: 0.015 m\n",

-        "length of array is: 2.25 m\n"

-       ]

-      }

-     ],

-     "prompt_number": 7

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "EXAMPLE 6.8,PAGE NUMBER 283"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "from __future__ import division\n",

-      "from math import atan\n",

-      "\n",

-      "\n",

-      "# Variable Declaration\n",

-      "\n",

-      "\n",

-      "G = 9             # required gain in dB\n",

-      "f_l = 125         # lowest frequency in MHz\n",

-      "f_l = 125*10**6   # lowest frequency in Hz\n",

-      "f_h = 500         # highest frequency in MHz\n",

-      "f_h = 500*10**6   # lowest frequency in Hz\n",

-      "c = 3*10**8       # speed of light in m/s\n",

-      "tau = 0.861       # scaling factor\n",

-      "sigma = 0.162     # spacing factor\n",

-      "\n",

-      "\n",

-      "#calculation\n",

-      "\n",

-      "\n",

-      "lamda_l = c/f_l  # longest wavelength in m\n",

-      "lamda_s = c/f_h  # shortest wavelength in m\n",

-      "alpha = 2*atan((1-tau)/(4*sigma))  # wedge angle in Degrees\n",

-      "L1 =  lamda_l/2  # in m\n",

-      "L2 = tau*L1  # in m\n",

-      "L3 = tau*L2  # in m\n",

-      "L4 = tau*L3  # in m\n",

-      "L5 = tau*L4  # in m\n",

-      "L6 = tau*L5  # in m\n",

-      "L7 = tau*L6  # in m\n",

-      "L8 = tau*L7  # in m\n",

-      "L9 = tau*L8  # in m\n",

-      "L10 = tau*L9  # in m\n",

-      "L11 = tau*L10  # in m\n",

-      "\n",

-      "# element spacing relation\n",

-      "#formula : sn = 2*sigma*Ln\n",

-      "\n",

-      "\n",

-      "S1 = 2*sigma*L1  # in m\n",

-      "S2 = 2*sigma*L2  # in m\n",

-      "S3 = 2*sigma*L3  # in m\n",

-      "S4 = 2*sigma*L4  # in m\n",

-      "S5 = 2*sigma*L5  # in m\n",

-      "S6 = 2*sigma*L6  # in m\n",

-      "S7 = 2*sigma*L7  # in m\n",

-      "S8 = 2*sigma*L8  # in m\n",

-      "S9 = 2*sigma*L9  # in m\n",

-      "S10 = 2*sigma*L10  # in m\n",

-      "S11 = 2*sigma*L11  # in m\n",

-      "\n",

-      "\n",

-      "\n",

-      "#results\n",

-      "\n",

-      "\n",

-      "print(\"designing of log-periodic antenna:\")\n",

-      "\n",

-      "print \"L1 is:\",round(L1,4),\"m\"\n",

-      "print \"L2 is:\",round(L2,4),\"m\"\n",

-      "print \"L3 is:\",round(L3,4),\"m\"\n",

-      "print \"L4 is:\",round(L4,4),\"m\"\n",

-      "print \"L5 is:\",round(L5,4),\"m\"\n",

-      "print \"L6 is:\",round(L6,4),\"m\"\n",

-      "print \"L7 is:\",round(L7,4),\"m\"\n",

-      "print \"L8 is:\",round(L8,4),\"m\"\n",

-      "print \"L9 is:\",round(L9,4),\"m\"\n",

-      "print \"L10 is:\",round(L10,4),\"m\"\n",

-      "print \"L11 is:\",round(L11,4),\"m\"\n",

-      "\n",

-      "print \"elements spacing relation:\"\n",

-      "\n",

-      "print \"S1 is:\",round(S1,4),\"m\"\n",

-      "print \"S2 is:\",round(S2,4),\"m\"\n",

-      "print \"S3 is:\",round(S3,4),\"m\"\n",

-      "print \"S4 is:\",round(S4,4),\"m\"\n",

-      "print \"S5 is:\",round(S5,4),\"m\"\n",

-      "print \"S6 is:\",round(S6,4),\"m\"\n",

-      "print \"S7 is:\",round(S7,4),\"m\"\n",

-      "print \"S8 is:\",round(S8,4),\"m\"\n",

-      "print \"S9 is:\",round(S9,4),\"m\"\n",

-      "print \"S10 is:\",round(S10,4),\"m\"\n",

-      "print \"S11 is:\",round(S11,4),\"m\"\n",

-      "\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "designing of log-periodic antenna:\n",

-        "L1 is: 1.2 m\n",

-        "L2 is: 1.0332 m\n",

-        "L3 is: 0.8896 m\n",

-        "L4 is: 0.7659 m\n",

-        "L5 is: 0.6595 m\n",

-        "L6 is: 0.5678 m\n",

-        "L7 is: 0.4889 m\n",

-        "L8 is: 0.4209 m\n",

-        "L9 is: 0.3624 m\n",

-        "L10 is: 0.312 m\n",

-        "L11 is: 0.2687 m\n",

-        "elements spacing relation:\n",

-        "S1 is: 0.3888 m\n",

-        "S2 is: 0.3348 m\n",

-        "S3 is: 0.2882 m\n",

-        "S4 is: 0.2482 m\n",

-        "S5 is: 0.2137 m\n",

-        "S6 is: 0.184 m\n",

-        "S7 is: 0.1584 m\n",

-        "S8 is: 0.1364 m\n",

-        "S9 is: 0.1174 m\n",

-        "S10 is: 0.1011 m\n",

-        "S11 is: 0.087 m\n"

-       ]

-      }

-     ],

-     "prompt_number": 8

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "EXAMPLE 6.9,PAGE NUMBER 285"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "from math import pi,cos,sqrt\n",

-      "\n",

-      "\n",

-      "# Variable Declaration\n",

-      "\n",

-      "E_rms = 10  # electric field in mV/m\n",

-      "E_rms = 10*10 **-3  # electric field in V/m\n",

-      "f = 2  # frequency in MHz\n",

-      "f = 2*10 **6  # frequency in Hz\n",

-      "N = 10  # number of turns\n",

-      "phi = 0  # angle between the plane of loop and direction of incident wave in Degrees\n",

-      "S = 1.4  # area of loop antenna in m **2\n",

-      "c = 3*10 **8  # speed of light in m/s\n",

-      "\n",

-      "#calculation\n",

-      "\n",

-      "lamda = c/f  # wavelength in m\n",

-      "E_max = sqrt(2)*E_rms  # electric field in V/m\n",

-      "V_rms = (2*pi*E_max*S*N/lamda)*cos(phi)  # induced voltage\n",

-      "\n",

-      "#Result\n",

-      "\n",

-      "print \"induced voltage is:\",round(V_rms*1000,2),\"mV\"\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "induced voltage is: 8.29 mV\n"

-       ]

-      }

-     ],

-     "prompt_number": 9

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "EXAMPLE 6.10,PAGE NUMBER 285"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "\n",

-      "# Variable Declaration\n",

-      "\n",

-      "\n",

-      "D = 0.5  # diameter of loop antenna in m\n",

-      "a = D/2  # radius of loop antenna in m\n",

-      "f = 1  # frequency in MHz\n",

-      "f = 1*10**6  # frequency in Hz\n",

-      "c = 3*10**8  # speed of light in m/s\n",

-      "\n",

-      "#calculation\n",

-      "\n",

-      "lamda = c/f  # wavelength in m\n",

-      "Rr = 3720*(a/lamda)  # radiation resistance of loop antenna in ohm\n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "\n",

-      "print \"radiation resistance of loop antenna is:\",Rr,\"ohm\"\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "radiation resistance of loop antenna is: 3.1 ohm\n"

-       ]

-      }

-     ],

-     "prompt_number": 10

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "EXAMPLE 6.11,PAGE NUMBER 285-286"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "from __future__ import division\n",

-      "from math import pi\n",

-      "\n",

-      "# Variable Declaration\n",

-      "\n",

-      "a = 0.5  # radius of loop antenna in m\n",

-      "f = 0.9  # frequency in MHz\n",

-      "f = 0.9*10**6  # frequency in Hz\n",

-      "c = 3*10**8  # speed of light in m/s\n",

-      "\n",

-      "#calculation\n",

-      "\n",

-      "lamda = c/f  # wavelength in m\n",

-      "k = (2*pi*a)/lamda  # constant\n",

-      "\n",

-      "#Results\n",

-      "\n",

-      "print \"the value of k is:\",round(k,2)\n",

-      "print \"since,k<1/3\"\n",

-      "print \"So Directivity of loop antenna is D = 1.5\"\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "the value of k is: 0.01\n",

-        "since,k<1/3\n",

-        "So Directivity of loop antenna is D = 1.5\n"

-       ]

-      }

-     ],

-     "prompt_number": 11

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "EXAMPLE 6.13,PAGE NUMBER 286"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "from sympy import Symbol\n",

-      "\n",

-      "#variable declaration and calculation\n",

-      "\n",

-      "Lm = Symbol('Lm')  # defining Lm as lambda\n",

-      "d = 1.5*Lm  # diameter of antenna in m\n",

-      "a = d/2  # radius of antenna in m\n",

-      "Rr = 3720*(a/Lm)  # radiation resistance of loop antenna in ohm\n",

-      "D = 4.25*(a/Lm) # Directivity of the loop antenna\n",

-      "\n",

-      "#results\n",

-      "\n",

-      "print \"radiation resistance of the loop antenna is:\",round(Rr,0),\"ohm\"\n",

-      "print \"Directivity of the loop antenna is:\",round(D,4)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "radiation resistance of the loop antenna is: 2790.0 ohm\n",

-        "Directivity of the loop antenna is: 3.1875\n"

-       ]

-      }

-     ],

-     "prompt_number": 12

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "EXAMPLE 6.14,PAGE NUMBER 287"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "from math import sqrt,pi\n",

-      "from sympy import Symbol\n",

-      "\n",

-      "#Variable declaration\n",

-      "\n",

-      "Gp = 28  # power gain\n",

-      "\n",

-      "#calculations\n",

-      "\n",

-      "Lm = Symbol('Lm')  # defining Lm as lamda\n",

-      "d = Lm/2           # length of dipole\n",

-      "\n",

-      "#formula : Gp = 4*(L/lamda)\n",

-      "\n",

-      "L = Gp*Lm/4  # array length\n",

-      "N = 7*2      # Number of elements in the array when spaced at lamda/2\n",

-      "\n",

-      "# formula : B.W = 2*sqrt((2*/N)*(lamda/d))\n",

-      "\n",

-      "BW = 2*sqrt(2*Lm/(N*d))  # null-to-null beam width in radians\n",

-      "BW_d = BW*180/pi         # null-to-null beam width in degrees\n",

-      "\n",

-      "#Results\n",

-      "\n",

-      "print \"Number of elements in the array when spaced at lamda/2 are:\",N\n",

-      "print \"array length(where Lm is wavelength in m) is:\",L,\"m\"\n",

-      "print \"null-to-null beam width is:\",round(BW_d,1),\"degrees\"\n",

-      "\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Number of elements in the array when spaced at lamda/2 are: 14\n",

-        "array length(where Lm is wavelength in m) is: 7*Lm m\n",

-        "null-to-null beam width is: 61.3 degrees\n"

-       ]

-      }

-     ],

-     "prompt_number": 13

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "EXAMPLE 6.15,PAGE NUMBER 287"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "from __future__ import division\n",

-      "from math import pi,sqrt\n",

-      "\n",

-      "\n",

-      "# Variable Declaration\n",

-      "\n",

-      "S = 0.05        # spacing in m\n",

-      "Dh = 0.1        # diameter of helical antenna in m\n",

-      "N = 20          # number of turns\n",

-      "f = 1000        # frequency in MHz\n",

-      "f = 1000*10**6  # frequency in MHz\n",

-      "c = 3*10**8     # speed of light in m/s\n",

-      "\n",

-      "\n",

-      "#calculation\n",

-      "\n",

-      "\n",

-      "lamda = c/f     # wavelength in m\n",

-      "C = pi*Dh       # circumfrence of helix in m\n",

-      "La = N*S        # axial legth in m\n",

-      "phi_not = (115*(lamda**(3/2))/(C*sqrt(La)))   # B.W.F.N., null-to-null beamwidth of main beam in Degreess\n",

-      "phi = (52*lamda**(3/2)/(C*sqrt(La)))          # H.P.B.W, half power beamwidth in Degreess\n",

-      "D = (15*N*C**2*S/(lamda)**3)                  # Directivity\n",

-      "\n",

-      "#Results\n",

-      "\n",

-      "print \"B.W.F.N., null-to-null beamwidth of main beam is:\",round(phi_not,1),\"degrees\"\n",

-      "print \"H.P.B.W, half power beamwidth is:\",round(phi,1),\"degrees\"\n",

-      "print \"Directivity is:\",round(D,2)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "B.W.F.N., null-to-null beamwidth of main beam is: 60.1 degrees\n",

-        "H.P.B.W, half power beamwidth is: 27.2 degrees\n",

-        "Directivity is: 54.83\n"

-       ]

-      }

-     ],

-     "prompt_number": 14

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/TestContribution/bilal.ipynb b/TestContribution/bilal.ipynb
deleted file mode 100755
index 22d13091..00000000
--- a/TestContribution/bilal.ipynb
+++ /dev/null
@@ -1,406 +0,0 @@
-{

- "metadata": {

-  "name": "",

-  "signature": "sha256:e19af2f3d200c02cdde989919b1864a16727820a7b37667c650dffdfc779957b"

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 25: Resonance"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 25.1, page no. 754"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import numpy as np\n",

-      "\n",

-      "#Variable declaration\n",

-      "L = 8  # Value of Inductor (8-H)\n",

-      "C = 20e-6  #Value of Capacitor (20-uF)\n",

-      "p = 3.142  #Value of pi\n",

-      "\n",

-      "#Calculation\n",

-      "a = np.sqrt(L*C)\n",

-      "fr = 1/(2*p*a)\n",

-      "\n",

-      "#Result\n",

-      "print \"Resonant frequency is\",float(fr), \"Hz i.e 12.6 Hz\""

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Resonant frequency is 12.5806717862 Hz i.e 12.6 Hz\n"

-       ]

-      }

-     ],

-     "prompt_number": 36

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 25.2, page no. 755"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import numpy as np\n",

-      "\n",

-      "#Variable declaration\n",

-      "L = 2e-6  # Value of Inductor (2-uH)\n",

-      "C = 3e-12  #Value of Capacitor (3-pF)\n",

-      "p = 3.142  #Value of pi\n",

-      "\n",

-      "#Calculation\n",

-      "a = np.sqrt(L*C)\n",

-      "fr = 1/(2*p*a)\n",

-      "\n",

-      "#Result\n",

-      "print \"Resonant frequency is\",float(fr), \"Hz i.e 65 MHz\""

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Resonant frequency is 64966309.7492 Hz i.e 65 MHz\n"

-       ]

-      }

-     ],

-     "prompt_number": 35

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 25.3, page no. 756"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "#Variable declaration\n",

-      "L = 239e-6  # Value of Inductor (239-uH)\n",

-      "f = 1000*10^3 #Frequency (1000 KHz)\n",

-      "p = 3.142  #Value of pi\n",

-      "\n",

-      "#Calculation\n",

-      "a = p*p\n",

-      "b = f*f\n",

-      "C = 1/(4*a*b*L)\n",

-      "\n",

-      "#Result\n",

-      "print \"Value of Capacitor is\",float(C), \"F i.e 106 pF\""

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Value of Capacitor is 1.05893477038e-06 F i.e 106 pF\n"

-       ]

-      }

-     ],

-     "prompt_number": 34

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 25.4, page no. 756"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "#Variable declaration\n",

-      "C = 106e-12  # Value of Capacitor (106-pF)\n",

-      "f = 1000000 #Frequency (1 MHz)\n",

-      "p = 3.142  #Value of pi\n",

-      "\n",

-      "#Calculation\n",

-      "a = 4*(p*p)\n",

-      "b = f*f\n",

-      "c = a*b*C\n",

-      "L = 1/(a*C*b)\n",

-      "\n",

-      "#Result\n",

-      "print \"Value of Inductor is\",float(L), \"H i.e 239 uH\""

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Value of Inductor is 0.000238903098251 H i.e 239 uH\n"

-       ]

-      }

-     ],

-     "prompt_number": 25

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 25.5, page no. 759"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "#Variable declaration\n",

-      "Vo = 100e-3  #Output Voltage(100-mV)\n",

-      "Vi = 2e-3 #Input Voltage(2-mV)\n",

-      "\n",

-      "#Calculation\n",

-      "Q = Vo/Vi\n",

-      "\n",

-      "#Result\n",

-      "print \"Value of Q is\",round(Q),"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Value of Q is 50.0\n"

-       ]

-      }

-     ],

-     "prompt_number": 38

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 25.6, page no. 759"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "#Variable declaration\n",

-      "Q = 50  #Quality Factor\n",

-      "L = 250e-6  # Value of Inductor (250-uH)\n",

-      "f = 400000 #Frequency (400 KHz)\n",

-      "p = 3.142  #Value of pi\n",

-      "\n",

-      "#Calculation\n",

-      "x = 2*p*f*L\n",

-      "rs = x/Q\n",

-      "\n",

-      "#Result\n",

-      "print \"Value of AC resistance is\",float(rs),\"Ohms\""

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Value of AC resistance is 12.568\n"

-       ]

-      }

-     ],

-     "prompt_number": 43

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 25.7, page no. 761"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "print \"Because they divide VT equally, ZEQ is 225 kOhms, the same as R1. The amount of input voltage does not matter, as the voltage division determines the relative proportions between R1 and ZEQ. With 225 kOhms for ZEQ and 1.5 kOhms for XL, the Q is 225\u20441.5, or Q = 150.\""

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Because they divide VT equally, ZEQ is 225 kOhms, the same as R1. The amount of input voltage does not matter, as the voltage division determines the relative proportions between R1 and ZEQ. With 225 kOhms for ZEQ and 1.5 kOhms for XL, the Q is 225\u20441.5, or Q = 150.\n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 25.8, page no. 761"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "#Variable declaration\n",

-      "Z = 17600  #Equivalent Impedence\n",

-      "L = 350e-6  # Value of Inductor (350-uH)\n",

-      "f = 200000 #Frequency (200 KHz)\n",

-      "p = 3.142  #Value of pi\n",

-      "\n",

-      "#Calculation\n",

-      "x = 2*p*f*L\n",

-      "Q = Z/x\n",

-      "\n",

-      "#Result\n",

-      "print \"Value of Quality factor is\", round(Q)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Value of Quality factor is 40.0\n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 25.9, page no. 764"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "#Variable declaration\n",

-      "Q = 100  #Quality Factor\n",

-      "fr = 2000000 # Resonant frequency (2000 KHz)\n",

-      "\n",

-      "#Calculation\n",

-      "f = fr/Q\n",

-      "f1 = fr-(f/2)\n",

-      "f2 = fr+(f/2)\n",

-      "\n",

-      "#Result\n",

-      "print \"The total Bandwidth is\",round(f),\"Hz\"\n",

-      "print \"The edge frequency f1 is\",round(f1),\"Hz\"\n",

-      "print \"The edge frequency f2 is\",round(f2),\"Hz\""

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "The total Bandwidth is 20000.0 Hz\n",

-        "The edge frequency f1 is 1990000.0 Hz\n",

-        "The edge frequency f2 is 2010000.0 Hz\n"

-       ]

-      }

-     ],

-     "prompt_number": 3

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 25.10, page no. 764"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "#Variable declaration\n",

-      "Q = 100  #Quality Factor\n",

-      "fr = 6000000 # Resonant frequency (6000 KHz)\n",

-      "\n",

-      "#Calculation\n",

-      "f = fr/Q\n",

-      "f1 = fr-(f/2)\n",

-      "f2 = fr+(f/2)\n",

-      "\n",

-      "#Result\n",

-      "print \"The total Bandwidth is\",round(f),\"Hz\"\n",

-      "print \"The edge frequency f1 is\",round(f1),\"Hz\"\n",

-      "print \"The edge frequency f2 is\",round(f2),\"Hz\""

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "The total Bandwidth is 60000.0 Hz\n",

-        "The edge frequency f1 is 5970000.0 Hz\n",

-        "The edge frequency f2 is 6030000.0 Hz\n"

-       ]

-      }

-     ],

-     "prompt_number": 2

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [],

-     "language": "python",

-     "metadata": {},

-     "outputs": []

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/TestContribution/bilal_1.ipynb b/TestContribution/bilal_1.ipynb
deleted file mode 100755
index 22d13091..00000000
--- a/TestContribution/bilal_1.ipynb
+++ /dev/null
@@ -1,406 +0,0 @@
-{

- "metadata": {

-  "name": "",

-  "signature": "sha256:e19af2f3d200c02cdde989919b1864a16727820a7b37667c650dffdfc779957b"

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 25: Resonance"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 25.1, page no. 754"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import numpy as np\n",

-      "\n",

-      "#Variable declaration\n",

-      "L = 8  # Value of Inductor (8-H)\n",

-      "C = 20e-6  #Value of Capacitor (20-uF)\n",

-      "p = 3.142  #Value of pi\n",

-      "\n",

-      "#Calculation\n",

-      "a = np.sqrt(L*C)\n",

-      "fr = 1/(2*p*a)\n",

-      "\n",

-      "#Result\n",

-      "print \"Resonant frequency is\",float(fr), \"Hz i.e 12.6 Hz\""

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Resonant frequency is 12.5806717862 Hz i.e 12.6 Hz\n"

-       ]

-      }

-     ],

-     "prompt_number": 36

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 25.2, page no. 755"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import numpy as np\n",

-      "\n",

-      "#Variable declaration\n",

-      "L = 2e-6  # Value of Inductor (2-uH)\n",

-      "C = 3e-12  #Value of Capacitor (3-pF)\n",

-      "p = 3.142  #Value of pi\n",

-      "\n",

-      "#Calculation\n",

-      "a = np.sqrt(L*C)\n",

-      "fr = 1/(2*p*a)\n",

-      "\n",

-      "#Result\n",

-      "print \"Resonant frequency is\",float(fr), \"Hz i.e 65 MHz\""

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Resonant frequency is 64966309.7492 Hz i.e 65 MHz\n"

-       ]

-      }

-     ],

-     "prompt_number": 35

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 25.3, page no. 756"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "#Variable declaration\n",

-      "L = 239e-6  # Value of Inductor (239-uH)\n",

-      "f = 1000*10^3 #Frequency (1000 KHz)\n",

-      "p = 3.142  #Value of pi\n",

-      "\n",

-      "#Calculation\n",

-      "a = p*p\n",

-      "b = f*f\n",

-      "C = 1/(4*a*b*L)\n",

-      "\n",

-      "#Result\n",

-      "print \"Value of Capacitor is\",float(C), \"F i.e 106 pF\""

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Value of Capacitor is 1.05893477038e-06 F i.e 106 pF\n"

-       ]

-      }

-     ],

-     "prompt_number": 34

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 25.4, page no. 756"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "#Variable declaration\n",

-      "C = 106e-12  # Value of Capacitor (106-pF)\n",

-      "f = 1000000 #Frequency (1 MHz)\n",

-      "p = 3.142  #Value of pi\n",

-      "\n",

-      "#Calculation\n",

-      "a = 4*(p*p)\n",

-      "b = f*f\n",

-      "c = a*b*C\n",

-      "L = 1/(a*C*b)\n",

-      "\n",

-      "#Result\n",

-      "print \"Value of Inductor is\",float(L), \"H i.e 239 uH\""

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Value of Inductor is 0.000238903098251 H i.e 239 uH\n"

-       ]

-      }

-     ],

-     "prompt_number": 25

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 25.5, page no. 759"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "#Variable declaration\n",

-      "Vo = 100e-3  #Output Voltage(100-mV)\n",

-      "Vi = 2e-3 #Input Voltage(2-mV)\n",

-      "\n",

-      "#Calculation\n",

-      "Q = Vo/Vi\n",

-      "\n",

-      "#Result\n",

-      "print \"Value of Q is\",round(Q),"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Value of Q is 50.0\n"

-       ]

-      }

-     ],

-     "prompt_number": 38

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 25.6, page no. 759"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "#Variable declaration\n",

-      "Q = 50  #Quality Factor\n",

-      "L = 250e-6  # Value of Inductor (250-uH)\n",

-      "f = 400000 #Frequency (400 KHz)\n",

-      "p = 3.142  #Value of pi\n",

-      "\n",

-      "#Calculation\n",

-      "x = 2*p*f*L\n",

-      "rs = x/Q\n",

-      "\n",

-      "#Result\n",

-      "print \"Value of AC resistance is\",float(rs),\"Ohms\""

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Value of AC resistance is 12.568\n"

-       ]

-      }

-     ],

-     "prompt_number": 43

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 25.7, page no. 761"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "print \"Because they divide VT equally, ZEQ is 225 kOhms, the same as R1. The amount of input voltage does not matter, as the voltage division determines the relative proportions between R1 and ZEQ. With 225 kOhms for ZEQ and 1.5 kOhms for XL, the Q is 225\u20441.5, or Q = 150.\""

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Because they divide VT equally, ZEQ is 225 kOhms, the same as R1. The amount of input voltage does not matter, as the voltage division determines the relative proportions between R1 and ZEQ. With 225 kOhms for ZEQ and 1.5 kOhms for XL, the Q is 225\u20441.5, or Q = 150.\n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 25.8, page no. 761"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "#Variable declaration\n",

-      "Z = 17600  #Equivalent Impedence\n",

-      "L = 350e-6  # Value of Inductor (350-uH)\n",

-      "f = 200000 #Frequency (200 KHz)\n",

-      "p = 3.142  #Value of pi\n",

-      "\n",

-      "#Calculation\n",

-      "x = 2*p*f*L\n",

-      "Q = Z/x\n",

-      "\n",

-      "#Result\n",

-      "print \"Value of Quality factor is\", round(Q)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Value of Quality factor is 40.0\n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 25.9, page no. 764"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "#Variable declaration\n",

-      "Q = 100  #Quality Factor\n",

-      "fr = 2000000 # Resonant frequency (2000 KHz)\n",

-      "\n",

-      "#Calculation\n",

-      "f = fr/Q\n",

-      "f1 = fr-(f/2)\n",

-      "f2 = fr+(f/2)\n",

-      "\n",

-      "#Result\n",

-      "print \"The total Bandwidth is\",round(f),\"Hz\"\n",

-      "print \"The edge frequency f1 is\",round(f1),\"Hz\"\n",

-      "print \"The edge frequency f2 is\",round(f2),\"Hz\""

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "The total Bandwidth is 20000.0 Hz\n",

-        "The edge frequency f1 is 1990000.0 Hz\n",

-        "The edge frequency f2 is 2010000.0 Hz\n"

-       ]

-      }

-     ],

-     "prompt_number": 3

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 25.10, page no. 764"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "#Variable declaration\n",

-      "Q = 100  #Quality Factor\n",

-      "fr = 6000000 # Resonant frequency (6000 KHz)\n",

-      "\n",

-      "#Calculation\n",

-      "f = fr/Q\n",

-      "f1 = fr-(f/2)\n",

-      "f2 = fr+(f/2)\n",

-      "\n",

-      "#Result\n",

-      "print \"The total Bandwidth is\",round(f),\"Hz\"\n",

-      "print \"The edge frequency f1 is\",round(f1),\"Hz\"\n",

-      "print \"The edge frequency f2 is\",round(f2),\"Hz\""

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "The total Bandwidth is 60000.0 Hz\n",

-        "The edge frequency f1 is 5970000.0 Hz\n",

-        "The edge frequency f2 is 6030000.0 Hz\n"

-       ]

-      }

-     ],

-     "prompt_number": 2

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [],

-     "language": "python",

-     "metadata": {},

-     "outputs": []

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/TestContribution/bilal_2.ipynb b/TestContribution/bilal_2.ipynb
deleted file mode 100755
index 22d13091..00000000
--- a/TestContribution/bilal_2.ipynb
+++ /dev/null
@@ -1,406 +0,0 @@
-{

- "metadata": {

-  "name": "",

-  "signature": "sha256:e19af2f3d200c02cdde989919b1864a16727820a7b37667c650dffdfc779957b"

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 25: Resonance"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 25.1, page no. 754"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import numpy as np\n",

-      "\n",

-      "#Variable declaration\n",

-      "L = 8  # Value of Inductor (8-H)\n",

-      "C = 20e-6  #Value of Capacitor (20-uF)\n",

-      "p = 3.142  #Value of pi\n",

-      "\n",

-      "#Calculation\n",

-      "a = np.sqrt(L*C)\n",

-      "fr = 1/(2*p*a)\n",

-      "\n",

-      "#Result\n",

-      "print \"Resonant frequency is\",float(fr), \"Hz i.e 12.6 Hz\""

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Resonant frequency is 12.5806717862 Hz i.e 12.6 Hz\n"

-       ]

-      }

-     ],

-     "prompt_number": 36

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 25.2, page no. 755"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import numpy as np\n",

-      "\n",

-      "#Variable declaration\n",

-      "L = 2e-6  # Value of Inductor (2-uH)\n",

-      "C = 3e-12  #Value of Capacitor (3-pF)\n",

-      "p = 3.142  #Value of pi\n",

-      "\n",

-      "#Calculation\n",

-      "a = np.sqrt(L*C)\n",

-      "fr = 1/(2*p*a)\n",

-      "\n",

-      "#Result\n",

-      "print \"Resonant frequency is\",float(fr), \"Hz i.e 65 MHz\""

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Resonant frequency is 64966309.7492 Hz i.e 65 MHz\n"

-       ]

-      }

-     ],

-     "prompt_number": 35

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 25.3, page no. 756"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "#Variable declaration\n",

-      "L = 239e-6  # Value of Inductor (239-uH)\n",

-      "f = 1000*10^3 #Frequency (1000 KHz)\n",

-      "p = 3.142  #Value of pi\n",

-      "\n",

-      "#Calculation\n",

-      "a = p*p\n",

-      "b = f*f\n",

-      "C = 1/(4*a*b*L)\n",

-      "\n",

-      "#Result\n",

-      "print \"Value of Capacitor is\",float(C), \"F i.e 106 pF\""

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Value of Capacitor is 1.05893477038e-06 F i.e 106 pF\n"

-       ]

-      }

-     ],

-     "prompt_number": 34

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 25.4, page no. 756"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "#Variable declaration\n",

-      "C = 106e-12  # Value of Capacitor (106-pF)\n",

-      "f = 1000000 #Frequency (1 MHz)\n",

-      "p = 3.142  #Value of pi\n",

-      "\n",

-      "#Calculation\n",

-      "a = 4*(p*p)\n",

-      "b = f*f\n",

-      "c = a*b*C\n",

-      "L = 1/(a*C*b)\n",

-      "\n",

-      "#Result\n",

-      "print \"Value of Inductor is\",float(L), \"H i.e 239 uH\""

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Value of Inductor is 0.000238903098251 H i.e 239 uH\n"

-       ]

-      }

-     ],

-     "prompt_number": 25

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 25.5, page no. 759"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "#Variable declaration\n",

-      "Vo = 100e-3  #Output Voltage(100-mV)\n",

-      "Vi = 2e-3 #Input Voltage(2-mV)\n",

-      "\n",

-      "#Calculation\n",

-      "Q = Vo/Vi\n",

-      "\n",

-      "#Result\n",

-      "print \"Value of Q is\",round(Q),"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Value of Q is 50.0\n"

-       ]

-      }

-     ],

-     "prompt_number": 38

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 25.6, page no. 759"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "#Variable declaration\n",

-      "Q = 50  #Quality Factor\n",

-      "L = 250e-6  # Value of Inductor (250-uH)\n",

-      "f = 400000 #Frequency (400 KHz)\n",

-      "p = 3.142  #Value of pi\n",

-      "\n",

-      "#Calculation\n",

-      "x = 2*p*f*L\n",

-      "rs = x/Q\n",

-      "\n",

-      "#Result\n",

-      "print \"Value of AC resistance is\",float(rs),\"Ohms\""

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Value of AC resistance is 12.568\n"

-       ]

-      }

-     ],

-     "prompt_number": 43

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 25.7, page no. 761"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "print \"Because they divide VT equally, ZEQ is 225 kOhms, the same as R1. The amount of input voltage does not matter, as the voltage division determines the relative proportions between R1 and ZEQ. With 225 kOhms for ZEQ and 1.5 kOhms for XL, the Q is 225\u20441.5, or Q = 150.\""

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Because they divide VT equally, ZEQ is 225 kOhms, the same as R1. The amount of input voltage does not matter, as the voltage division determines the relative proportions between R1 and ZEQ. With 225 kOhms for ZEQ and 1.5 kOhms for XL, the Q is 225\u20441.5, or Q = 150.\n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 25.8, page no. 761"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "#Variable declaration\n",

-      "Z = 17600  #Equivalent Impedence\n",

-      "L = 350e-6  # Value of Inductor (350-uH)\n",

-      "f = 200000 #Frequency (200 KHz)\n",

-      "p = 3.142  #Value of pi\n",

-      "\n",

-      "#Calculation\n",

-      "x = 2*p*f*L\n",

-      "Q = Z/x\n",

-      "\n",

-      "#Result\n",

-      "print \"Value of Quality factor is\", round(Q)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Value of Quality factor is 40.0\n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 25.9, page no. 764"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "#Variable declaration\n",

-      "Q = 100  #Quality Factor\n",

-      "fr = 2000000 # Resonant frequency (2000 KHz)\n",

-      "\n",

-      "#Calculation\n",

-      "f = fr/Q\n",

-      "f1 = fr-(f/2)\n",

-      "f2 = fr+(f/2)\n",

-      "\n",

-      "#Result\n",

-      "print \"The total Bandwidth is\",round(f),\"Hz\"\n",

-      "print \"The edge frequency f1 is\",round(f1),\"Hz\"\n",

-      "print \"The edge frequency f2 is\",round(f2),\"Hz\""

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "The total Bandwidth is 20000.0 Hz\n",

-        "The edge frequency f1 is 1990000.0 Hz\n",

-        "The edge frequency f2 is 2010000.0 Hz\n"

-       ]

-      }

-     ],

-     "prompt_number": 3

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 25.10, page no. 764"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "#Variable declaration\n",

-      "Q = 100  #Quality Factor\n",

-      "fr = 6000000 # Resonant frequency (6000 KHz)\n",

-      "\n",

-      "#Calculation\n",

-      "f = fr/Q\n",

-      "f1 = fr-(f/2)\n",

-      "f2 = fr+(f/2)\n",

-      "\n",

-      "#Result\n",

-      "print \"The total Bandwidth is\",round(f),\"Hz\"\n",

-      "print \"The edge frequency f1 is\",round(f1),\"Hz\"\n",

-      "print \"The edge frequency f2 is\",round(f2),\"Hz\""

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "The total Bandwidth is 60000.0 Hz\n",

-        "The edge frequency f1 is 5970000.0 Hz\n",

-        "The edge frequency f2 is 6030000.0 Hz\n"

-       ]

-      }

-     ],

-     "prompt_number": 2

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [],

-     "language": "python",

-     "metadata": {},

-     "outputs": []

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/TestContribution/bilal_3.ipynb b/TestContribution/bilal_3.ipynb
deleted file mode 100755
index 22d13091..00000000
--- a/TestContribution/bilal_3.ipynb
+++ /dev/null
@@ -1,406 +0,0 @@
-{

- "metadata": {

-  "name": "",

-  "signature": "sha256:e19af2f3d200c02cdde989919b1864a16727820a7b37667c650dffdfc779957b"

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 25: Resonance"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 25.1, page no. 754"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import numpy as np\n",

-      "\n",

-      "#Variable declaration\n",

-      "L = 8  # Value of Inductor (8-H)\n",

-      "C = 20e-6  #Value of Capacitor (20-uF)\n",

-      "p = 3.142  #Value of pi\n",

-      "\n",

-      "#Calculation\n",

-      "a = np.sqrt(L*C)\n",

-      "fr = 1/(2*p*a)\n",

-      "\n",

-      "#Result\n",

-      "print \"Resonant frequency is\",float(fr), \"Hz i.e 12.6 Hz\""

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Resonant frequency is 12.5806717862 Hz i.e 12.6 Hz\n"

-       ]

-      }

-     ],

-     "prompt_number": 36

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 25.2, page no. 755"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import numpy as np\n",

-      "\n",

-      "#Variable declaration\n",

-      "L = 2e-6  # Value of Inductor (2-uH)\n",

-      "C = 3e-12  #Value of Capacitor (3-pF)\n",

-      "p = 3.142  #Value of pi\n",

-      "\n",

-      "#Calculation\n",

-      "a = np.sqrt(L*C)\n",

-      "fr = 1/(2*p*a)\n",

-      "\n",

-      "#Result\n",

-      "print \"Resonant frequency is\",float(fr), \"Hz i.e 65 MHz\""

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Resonant frequency is 64966309.7492 Hz i.e 65 MHz\n"

-       ]

-      }

-     ],

-     "prompt_number": 35

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 25.3, page no. 756"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "#Variable declaration\n",

-      "L = 239e-6  # Value of Inductor (239-uH)\n",

-      "f = 1000*10^3 #Frequency (1000 KHz)\n",

-      "p = 3.142  #Value of pi\n",

-      "\n",

-      "#Calculation\n",

-      "a = p*p\n",

-      "b = f*f\n",

-      "C = 1/(4*a*b*L)\n",

-      "\n",

-      "#Result\n",

-      "print \"Value of Capacitor is\",float(C), \"F i.e 106 pF\""

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Value of Capacitor is 1.05893477038e-06 F i.e 106 pF\n"

-       ]

-      }

-     ],

-     "prompt_number": 34

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 25.4, page no. 756"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "#Variable declaration\n",

-      "C = 106e-12  # Value of Capacitor (106-pF)\n",

-      "f = 1000000 #Frequency (1 MHz)\n",

-      "p = 3.142  #Value of pi\n",

-      "\n",

-      "#Calculation\n",

-      "a = 4*(p*p)\n",

-      "b = f*f\n",

-      "c = a*b*C\n",

-      "L = 1/(a*C*b)\n",

-      "\n",

-      "#Result\n",

-      "print \"Value of Inductor is\",float(L), \"H i.e 239 uH\""

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Value of Inductor is 0.000238903098251 H i.e 239 uH\n"

-       ]

-      }

-     ],

-     "prompt_number": 25

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 25.5, page no. 759"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "#Variable declaration\n",

-      "Vo = 100e-3  #Output Voltage(100-mV)\n",

-      "Vi = 2e-3 #Input Voltage(2-mV)\n",

-      "\n",

-      "#Calculation\n",

-      "Q = Vo/Vi\n",

-      "\n",

-      "#Result\n",

-      "print \"Value of Q is\",round(Q),"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Value of Q is 50.0\n"

-       ]

-      }

-     ],

-     "prompt_number": 38

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 25.6, page no. 759"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "#Variable declaration\n",

-      "Q = 50  #Quality Factor\n",

-      "L = 250e-6  # Value of Inductor (250-uH)\n",

-      "f = 400000 #Frequency (400 KHz)\n",

-      "p = 3.142  #Value of pi\n",

-      "\n",

-      "#Calculation\n",

-      "x = 2*p*f*L\n",

-      "rs = x/Q\n",

-      "\n",

-      "#Result\n",

-      "print \"Value of AC resistance is\",float(rs),\"Ohms\""

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Value of AC resistance is 12.568\n"

-       ]

-      }

-     ],

-     "prompt_number": 43

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 25.7, page no. 761"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "print \"Because they divide VT equally, ZEQ is 225 kOhms, the same as R1. The amount of input voltage does not matter, as the voltage division determines the relative proportions between R1 and ZEQ. With 225 kOhms for ZEQ and 1.5 kOhms for XL, the Q is 225\u20441.5, or Q = 150.\""

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Because they divide VT equally, ZEQ is 225 kOhms, the same as R1. The amount of input voltage does not matter, as the voltage division determines the relative proportions between R1 and ZEQ. With 225 kOhms for ZEQ and 1.5 kOhms for XL, the Q is 225\u20441.5, or Q = 150.\n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 25.8, page no. 761"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "#Variable declaration\n",

-      "Z = 17600  #Equivalent Impedence\n",

-      "L = 350e-6  # Value of Inductor (350-uH)\n",

-      "f = 200000 #Frequency (200 KHz)\n",

-      "p = 3.142  #Value of pi\n",

-      "\n",

-      "#Calculation\n",

-      "x = 2*p*f*L\n",

-      "Q = Z/x\n",

-      "\n",

-      "#Result\n",

-      "print \"Value of Quality factor is\", round(Q)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Value of Quality factor is 40.0\n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 25.9, page no. 764"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "#Variable declaration\n",

-      "Q = 100  #Quality Factor\n",

-      "fr = 2000000 # Resonant frequency (2000 KHz)\n",

-      "\n",

-      "#Calculation\n",

-      "f = fr/Q\n",

-      "f1 = fr-(f/2)\n",

-      "f2 = fr+(f/2)\n",

-      "\n",

-      "#Result\n",

-      "print \"The total Bandwidth is\",round(f),\"Hz\"\n",

-      "print \"The edge frequency f1 is\",round(f1),\"Hz\"\n",

-      "print \"The edge frequency f2 is\",round(f2),\"Hz\""

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "The total Bandwidth is 20000.0 Hz\n",

-        "The edge frequency f1 is 1990000.0 Hz\n",

-        "The edge frequency f2 is 2010000.0 Hz\n"

-       ]

-      }

-     ],

-     "prompt_number": 3

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 25.10, page no. 764"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "#Variable declaration\n",

-      "Q = 100  #Quality Factor\n",

-      "fr = 6000000 # Resonant frequency (6000 KHz)\n",

-      "\n",

-      "#Calculation\n",

-      "f = fr/Q\n",

-      "f1 = fr-(f/2)\n",

-      "f2 = fr+(f/2)\n",

-      "\n",

-      "#Result\n",

-      "print \"The total Bandwidth is\",round(f),\"Hz\"\n",

-      "print \"The edge frequency f1 is\",round(f1),\"Hz\"\n",

-      "print \"The edge frequency f2 is\",round(f2),\"Hz\""

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "The total Bandwidth is 60000.0 Hz\n",

-        "The edge frequency f1 is 5970000.0 Hz\n",

-        "The edge frequency f2 is 6030000.0 Hz\n"

-       ]

-      }

-     ],

-     "prompt_number": 2

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [],

-     "language": "python",

-     "metadata": {},

-     "outputs": []

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/TestContribution/ch3.ipynb b/TestContribution/ch3.ipynb
deleted file mode 100755
index 8becd279..00000000
--- a/TestContribution/ch3.ipynb
+++ /dev/null
@@ -1,941 +0,0 @@
-{
- "metadata": {
-  "name": ""
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 3 : The mechanical equivalent of  heat"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.1 pageno : 44"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "# Variables\n",
-      "m = 20;\t\t\t#calorimeter of water equivalent in gm\n",
-      "n = 1030;\t\t\t#weight of water in gm\n",
-      "p = 2;\t\t\t#no.of paddles\n",
-      "a = 10;\t\t\t#weight of each paddle in kg\n",
-      "s = 80;\t\t\t#dismath.tance between paddles in m\n",
-      "g = 980;\t\t\t#accelaration due to gravity in cm/sec**2\n",
-      "\n",
-      "# Calculations\n",
-      "E = (p*a*1000*g*s*100);\t\t\t#potential energy in dyne cm\n",
-      "T = (E)/(1050*4.18*10**7);\t\t\t#rise in temperature in deg.C\n",
-      "\n",
-      "# Result\n",
-      "print 'the rise in temperature of water is %3.2f deg.C'%(T)\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the rise in temperature of water is 3.57 deg.C\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.2 pageno : 45"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "# Variables\n",
-      "cp = 0.1;\t\t\t#specific heat of copper in kj/kg-K\n",
-      "w = 120;\t\t\t#weight of copper calorimeter in gm\n",
-      "a = 1400;\t\t\t#weight of paraffin oil in gm\n",
-      "cp1 = 0.6;\t\t\t#specific of parafin oil in kj/kg-K\n",
-      "b = 10**8;\t\t\t#force to rotate the paddle in dynes\n",
-      "T = 16;\t\t\t#rise in temperature in deg.C\n",
-      "n = 900;\t\t\t#no.of revolutions stirred \n",
-      "pi = 3.14;\t\t\t#value of pi\n",
-      "\n",
-      "# Calculations\n",
-      "c = 2*pi*b;\t\t\t#work done by a rotating paddle per rotation in dyne cm per rotation\n",
-      "d = c*n;\t\t\t#total work done in dyne cm \n",
-      "hc = w*cp*16;\t\t\t#heat gained by calorimeter in calories\n",
-      "hp = a*cp1*16;\t\t\t#heat gaained by paraffin oil in calories \n",
-      "J = d/(hc+hp);\t\t\t#mecanical equivalent of heat in erg/cal\n",
-      "\n",
-      "# Result\n",
-      "print 'mecanical equivalent of heat is %.2e erg/cal'%(J)\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "mecanical equivalent of heat is 4.15e+07 erg/cal\n"
-       ]
-      }
-     ],
-     "prompt_number": 2
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.3 pageno : 45"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "# Variables \n",
-      "cp = 0.12;\t\t\t#specific heat of iron in kj/kg-K\n",
-      "m = 25;\t\t\t#mass of iron in lb\n",
-      "h = 0.4;\t\t\t#horse power developed in 3 min\n",
-      "t = 3;\t\t\t#time taken to develop the horse power in min\n",
-      "T = 17;\t\t\t#raise in temp in deg.C\n",
-      "\n",
-      "# Calculations\n",
-      "w = h*33000*t;\t\t\t#total work done in ft-lb\n",
-      "H = m*cp*T;\t\t\t#aount of heat developed in B.Th.U\n",
-      "J = (w)/H;\t\t\t#the value of mechanical equivalent of heat\n",
-      "\n",
-      "# Result\n",
-      "print 'the mechanical equivalent of water is %3.1f ft-lb/B.Th.U'%(J)\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the mechanical equivalent of water is 776.5 ft-lb/B.Th.U\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.4 pageno : 45"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "# Variables \n",
-      "n = 2.;\t\t\t#no.of lead blocks\n",
-      "m = 210.;\t\t\t#mass of each lead block in gm\n",
-      "v = 20000.;\t\t\t#velocity of block relative to earth in cm/sec\n",
-      "J = 4.2*10**7;\t\t\t#mechanical equivalent of heat in ergs/calorie\n",
-      "cp = 0.03;\t\t\t#specific heat of lead in kj/kg-K\n",
-      "\n",
-      "# Calculations\n",
-      "E = (m*v**2)/2;\t\t\t#kinetic energy of each block in ergs\n",
-      "E2 = n*E;\t\t\t#total kinetic energy in ergs\n",
-      "T = E2/(J*m*n*cp);\t\t\t#mean rise in temperature in T\n",
-      "\n",
-      "# Result\n",
-      "print 'the mean rise in temperature is %3.1f deg.C'%(T)\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the mean rise in temperature is 158.7 deg.C\n"
-       ]
-      }
-     ],
-     "prompt_number": 4
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.5 pageno : 45"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "# Variables \n",
-      "h = 150;\t\t\t#height froom which ball fallen in ft\n",
-      "cp = 0.03;\t\t\t#specific heat of lead in kj/kg-K\n",
-      "J = 778;\t\t\t#mechanical equivalent of heat in ft lb/B.Th.U\n",
-      "\n",
-      "# Calculations\n",
-      "#work done in falling is equal to heat absorbed by the ball\n",
-      "T = 160./(J*cp)*(5./9);\t\t\t#the raise in temperature in T\n",
-      "\n",
-      "# Result\n",
-      "print 'the raise in temperature is %3.1f deg.C'%(T)\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the raise in temperature is 3.8 deg.C\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.6 pageno : 46"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "import math \n",
-      "# Variables \n",
-      "w = 26.6;\t\t\t#work done one horse in to raise the temperature in lb\n",
-      "T1 = 32.;\t\t\t#temperature at initial in deg.F\n",
-      "T2 = 212.;\t\t\t#temperature at final in deg.F\n",
-      "t = 2.5;\t\t\t#time to raise the tmperature in hrs\n",
-      "p = 25.;\t\t\t#percentage of heat lossed \n",
-      "\n",
-      "# Calculations\n",
-      "#only 75% of heat is utillised\n",
-      "x = w*180.*100.*778./((100-p)*150);\t\t\t#the rate at which horse worked\n",
-      "\n",
-      "# Result\n",
-      "print 'the rate at which horse worked is %3.0f ft-lb wt/min'%(x)\n",
-      "print \"Note : Answer in book is rounded off, Please calculate manually. This answer is accurate.\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the rate at which horse worked is 33112 ft-lb wt/min\n",
-        "Note : Answer in book is rounded off, Please calculate manually. This answer is accurate.\n"
-       ]
-      }
-     ],
-     "prompt_number": 7
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.7 pageno : 46"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "# Variables \n",
-      "l = 100.;\t\t\t#length of glass tube in cm\n",
-      "m = 500.;\t\t\t#mass of mercury in glass tube in gm\n",
-      "n = 20.;\t\t\t#number of times inverted i succession\n",
-      "cp = 0.03;\t\t\t#specific heat of mercury in cal/gm/deg.C\n",
-      "J = 4.2;\t\t\t#joule's equivalent in j/cal\n",
-      "g = 981.;\t\t\t#accelaration due to gravity in cm/s**2\n",
-      "\n",
-      "# Calculations\n",
-      "PE = m*g*l;\t\t\t#potential energy for each time in ergs\n",
-      "TE = PE*n;\t\t\t#total loss in ergs\n",
-      "T = TE/(m*cp*J*10**7);\t\t\t#rise in temperature in deg.C\n",
-      "#if T is the rise in temperature,then heat devoloped is m*cp*T\n",
-      "\n",
-      "# Result\n",
-      "print 'the rise in temperature is %3.2f deg.C'%(T)\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the rise in temperature is 1.56 deg.C\n"
-       ]
-      }
-     ],
-     "prompt_number": 8
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.8 page no : 46"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "\n",
-      "# Variables \n",
-      "d = 0.02;\t\t\t#diameter of the copper wire in cm\n",
-      "i = 1;\t\t\t#current in amp\n",
-      "T = 100;\t\t\t#maximum steady temperature in deg.C\n",
-      "r = 2.1;\t\t\t#resistance of the wire in ohm cm\n",
-      "J = 4.2;\t\t\t#mechanical equivalent of heat in j/cal\n",
-      "a = 3.14*d**2/4;\t\t\t#area of the copper wire in sq.cm\n",
-      "a2 = 1;\t\t\t#area of the copper surface in sq.cm\n",
-      "\n",
-      "# Calculations \n",
-      "l = 1/(2*3.14*d/2);\t\t\t#length corresponding to the area in cm\n",
-      "R = r*l/a;\t\t\t#resistance of the copper wire in ohm\n",
-      "w = R*a2**2;\t\t\t#work done in joule\n",
-      "h = w/J;\t\t\t#heat devoleped in cal\n",
-      "\n",
-      "# Result\n",
-      "print 'the heat developed is %.f calories'%(round(h,-1))\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the heat developed is 25360 calories\n"
-       ]
-      }
-     ],
-     "prompt_number": 11
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.9 pageno: 47"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "import math \n",
-      "\n",
-      "# Variables\n",
-      "h = 10000;\t\t\t#vertical height of water fall in cm\n",
-      "v = 5;\t\t\t    #volume disharged per sec in litres\n",
-      "J = 4.18;\t\t\t#joule's constant in j/cal\n",
-      "g = 981;\t\t\t#accelaration due to gravity in cm/sec**2\n",
-      "\n",
-      "# Calculations\n",
-      "m = v*1000;\t\t\t#mass of water disharged per sec in gm\n",
-      "w = m*h*g;\t\t\t#work done in falling through 100m in erg\n",
-      "H = (v*10**7 *g)/(J*10**7);\t#quantity of heat produced in cal\n",
-      "T = H/m;\t\t\t#rise in temperature in deg.C\n",
-      "\n",
-      "# Result\n",
-      "print 'the quantity of heat produced is %3f cal  \\\n",
-      "\\nthe rise in temperature is %3.2f deg.C'%(H,T)\n",
-      "\n",
-      "print \"Note : Answer for part A in book is wrong. Please calculate manually.\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the quantity of heat produced is 1173.444976 cal  \n",
-        "the rise in temperature is 0.23 deg.C\n",
-        "Note : Answer for part A in book is wrong. Please calculate manually.\n"
-       ]
-      }
-     ],
-     "prompt_number": 15
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.10 page no : 47"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "\n",
-      "# Variables \n",
-      "cp = 0.03;\t\t\t#specific heat of lead in kj/kg.k\n",
-      "v = 10000;\t\t\t#initial velocity of bullet in cm/sec\n",
-      "J = 4.2*10**7;\t\t\t#joules constant in ergs/cal\n",
-      "\n",
-      "# Calculations\n",
-      "ke = (v**2)/2;\t\t\t#kinetic energy of the bullet per unit mass in (cm/sec)**2\n",
-      "T = ke*95/(cp*J*100);\t\t\t#rise in temperature in deg.C\n",
-      "\n",
-      "# Result\n",
-      "print 'the rise in temperature is %3.1f deg.C'%(T)\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the rise in temperature is 37.7 deg.C\n"
-       ]
-      }
-     ],
-     "prompt_number": 16
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.11 page no : 47"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "# Variables \n",
-      "h = 5000.;\t\t\t#height of the niagara falls in cm\n",
-      "J = 4.2*10**7;\t\t#joules constant in ergs per cal\n",
-      "g = 981;\t\t\t#accelaration due to gravity in cm/sec**2\n",
-      "\n",
-      "#CALCULATIONS\n",
-      "w = h*g;\t\t\t#work done per unit mass in ergs/gn\n",
-      "T = w/J;\t\t\t#rise in temperature in deg.C\n",
-      "\n",
-      "# Result\n",
-      "print 'the rise in temperature is %3.2f deg.C'%(T)\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the rise in temperature is 0.12 deg.C\n"
-       ]
-      }
-     ],
-     "prompt_number": 17
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.12 page no : 48\n"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "import math \n",
-      "\n",
-      "# Variables \n",
-      "E1 = 3.75;\t\t\t#potential difference in v\n",
-      "E2 = 3.;\t\t\t#potential differnce in v\n",
-      "i1 = 2.5;\t\t\t#current in amp\n",
-      "i2 = 2;\t\t\t    #current in amp\n",
-      "T = 2.7;\t\t\t#the rise in temperature of the water in deg.C\n",
-      "m1 = 48.;\t\t\t#water flow rate at 3 volts in gm/min\n",
-      "m2 = 30.;\t\t\t#water flow rate at 3.75volts in gm/min\n",
-      "s = 1;\t\t\t    #specific heat of the water kj/kg-K\n",
-      "\n",
-      "# Calculations\n",
-      "J = (E1*i1-E2*i2)/(s*T*(m1-m2)/60);\t\t\t#the mechanical equivalent in j/cal\n",
-      "\n",
-      "# Result\n",
-      "print 'the mechanical equivalent is %3.3f j/cal'%(J)\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the mechanical equivalent is 4.167 j/cal\n"
-       ]
-      }
-     ],
-     "prompt_number": 18
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.13 page no : 48"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "\n",
-      "# Variables \n",
-      "R = 64*10**7;\t\t\t#mean radius of the earth in cm\n",
-      "cp = 0.15;\t\t\t#specific heat of earth in kj/kg-K\n",
-      "J = 4.2*10**7;\t\t\t#joules consmath.tant in erg/cal\n",
-      "\n",
-      "# Calculations\n",
-      "i = 2./5*R**2;\t\t\t#moment of inertia of the earth per unit mass in joules\n",
-      "w = (2*3.14)/(24*60*60);\t\t\t#angular velocity of the earth in rad/sec\n",
-      "T = (i*w**2)/(2*J*cp);\t\t\t#rise in temperature in deg.C\n",
-      "\n",
-      "# Result\n",
-      "print 'the rise in the temperature is %.1f deg C'%(T)\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the rise in the temperature is 68.7 deg C\n"
-       ]
-      }
-     ],
-     "prompt_number": 6
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.14 page no : 49"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "# Variables \n",
-      "cp = 1.25;\t\t\t#specific heat of helium inkj/kg-K\n",
-      "v = 1000;\t\t\t#volume of the gas in ml\n",
-      "w = 0.1785;\t\t\t#mass of the gas at N.T.P in gm\n",
-      "p = 76*13.6*981;\t#pressure of the gas at N.T.P in dynes\n",
-      "T = 273;\t\t\t#temperature at N.T.P in K\n",
-      "\n",
-      "# Calculations\n",
-      "V = 1000/w;\t\t\t#volume occupied by the 1gm of helium gas in cc\n",
-      "cv = cp/1.66;\t\t#specific heat at constant volume it is monatomuc gas kj/kg-K\n",
-      "r = p*V/T;\t\t\t#gas constant in cm**3.atm./K.mol\n",
-      "J = r/(cp-cv);\t\t#mechanical equivalent of heat in erg/cal\n",
-      "\n",
-      "# Result\n",
-      "print 'the mechanical equivalent of heat is %.2e ergs/calories'%(J)\n",
-      "print \"Note: answer slightly different because of rounding error.\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the mechanical equivalent of heat is 4.19e+07 ergs/calories\n",
-        "Note: answer slightly different because of rounding error.\n"
-       ]
-      }
-     ],
-     "prompt_number": 20
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "\n",
-      "Example 3.15 pageno : 49"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "# Variables \n",
-      "n = 1./273;     \t\t\t#coefficent of expaaansion of air\n",
-      "a = 0.001293;\t    \t\t#density of air in gm/cc\n",
-      "cp = 0.2389;\t\t    \t#specific heat at consmath.tant pressure in kj/kg.K\n",
-      "p = 76*13.6*981;\t\t\t#pressure at 0 deg.C in dynes\n",
-      "\n",
-      "# Calculations\n",
-      "J = (p*n)/(a*(cp-(cp/1.405)));\t\t\t#mechanical equivalent of heat\n",
-      "\n",
-      "# Result\n",
-      "print 'mechanical equivalent of heat is %.2e ergs/cal'%(J)\n",
-      "print \"Note: answer slightly different because of rounding error.\"\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "mechanical equivalent of heat is 4.17e+07 ergs/cal\n",
-        "Note: answer slightly different because of rounding error.\n"
-       ]
-      }
-     ],
-     "prompt_number": 22
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.16 pageno : 49"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "import math \n",
-      "# Variables \n",
-      "r = 120./60;\t\t\t#rate of flow of water in gm/sec\n",
-      "T1 = 27.30;\t\t\t#temperature at initial in deg.C\n",
-      "T2 = 33.75;\t\t\t#temperature at final in deg.C\n",
-      "v = 12.64;\t\t\t#potential drop in volts\n",
-      "s = 1.; \t\t\t#specific heat of water in kj/kg-K\n",
-      "i = 4.35;\t\t\t#current through the heating element in amp\n",
-      "\n",
-      "# Calculations\n",
-      "J = (v*i)/(r*s*(T2-T1));\t\t\t#the mechanical equivalent of heat in joule/calorie\n",
-      "\n",
-      "# Result\n",
-      "print 'the mechanical equivalent of heat is %3.2f j/cal'%(J)\n",
-      "print \"Note: answer slightly different because of rounding error.\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the mechanical equivalent of heat is 4.26 j/cal\n",
-        "Note: answer slightly different because of rounding error.\n"
-       ]
-      }
-     ],
-     "prompt_number": 24
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.17 page no : 50"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "\n",
-      "# Variables \n",
-      "cp = 6.865;\t\t\t#molar specific heat of hydrogen at consmath.tant pressure in kj/kg-K\n",
-      "cv = 4.880;\t\t\t#molar specific heat of hydrogen at consmath.tant volume in kj/kg-K\n",
-      "p = 1.013*10**6;\t\t\t#atmospheric pressure in dynes/cm**2\n",
-      "v = 22.4*10**3;\t\t\t#gram molar volume in ml\n",
-      "T = 273;\t\t\t#temperature at N.T.P in kelvins\n",
-      "\n",
-      "# Calculations\n",
-      "J = (p*v)/(T*(cp-cv));\t\t\t#mechanical equivalent of heat\n",
-      "\n",
-      "# Result\n",
-      "print 'the mechanical equivalent of heat is %.2e ergs/cal'%(J)\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the mechanical equivalent of heat is 4.19e+07 ergs/cal\n"
-       ]
-      }
-     ],
-     "prompt_number": 26
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.18 page no : 50"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "import math \n",
-      "# Variables\n",
-      "v = 1000.;\t\t\t#volume of hydrogen in ml\n",
-      "t = 273.;\t\t\t#tempature of hydrogen in kelvin\n",
-      "p = 76.;\t\t\t#pressure of hydrogen in mm of hg\n",
-      "w = 0.0896;\t\t\t#weigh of hydrogen in gm\n",
-      "cp = 3.409;\t\t\t#specific heat of hydogen in kj/kg-K\n",
-      "cv = 2.411;\t\t\t#specific heat of hydrogen in kj/kg-K\n",
-      "g = 981.;\t\t\t#accelaration due to gravity in cm/sec**2\n",
-      "a = 13.6;\t\t\t#density of mercury in gm/cm**2\n",
-      "\n",
-      "# Calculations\n",
-      "J = (p*v*g*a)/(w*t*(cp-cv));\t\t\t#mechanical equivalent of heat in ergs/cals\n",
-      "\n",
-      "# Result\n",
-      "print 'mechanical equivalent of heat is %.2e ergs/calorie'%(J)\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "mechanical equivalent of heat is 4.15e+07 ergs/calorie\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.19 page no : 50"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "# Variables\n",
-      "cp = 0.23;\t\t\t#specific heat at constant pressure in kj/kg-K\n",
-      "a = 1.18;\t\t\t#density of air in gm/lit\n",
-      "J = 4.2*10**7;\t\t\t#mechanical equivalent of heat in ergs/cal\n",
-      "t = 300;\t\t\t#temperature of air in kelvin\n",
-      "p = 73*13.6*981;\t\t\t#pressure of air in dynes\n",
-      "\t\t\t#cp-cv = (r/J) = pv/(tj)\n",
-      "\n",
-      "#CALCULATON\n",
-      "cv = cp-(p*1000/(a*t*J));\t\t\t#specific heat at constant volume in calories\n",
-      "\n",
-      "# Result\n",
-      "print 'the specific heat at constant volume is %.4f calories'%(cv)\n",
-      "print \"Note: answer slightly different because of rounding error.\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the specific heat at constant volume is 0.1645 calories\n",
-        "Note: answer slightly different because of rounding error.\n"
-       ]
-      }
-     ],
-     "prompt_number": 29
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.20 pageno : 51"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "# Variables\n",
-      "t1 = 0;\t\t\t#temperature of water in deg.C\n",
-      "t2 = 0;\t\t\t#temperature of ice in deg.C\n",
-      "J = 4.18*10**7;\t\t\t#the joules thomson coefficent in erg/cal\n",
-      "l = 80;\t\t\t#latent heat og fusion kj/kg\n",
-      "g = 981;\t\t\t#accelaration due to gravity in cm/sec**2\n",
-      " \n",
-      "# Calculations\n",
-      "h = l*J/(15*g);\t\t\t#height from which ice has fallen\n",
-      "\n",
-      "# Result\n",
-      "print 'the height from which ice has fallen is %.2e cm'%(h)\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the height from which ice has fallen is 2.27e+05 cm\n"
-       ]
-      }
-     ],
-     "prompt_number": 30
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.21 page no : 51"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "\n",
-      "# Variables\n",
-      "T = 80;\t\t\t#temperature of bullet in deg.C\n",
-      "cp = 0.03;\t\t\t#specific heat of lead in kj/kg-K\n",
-      "J = 4.2;\t\t\t#mechanical equivalent of heat in j/cal\n",
-      "\n",
-      "# Calculations\n",
-      "h = T*cp;\t\t\t#heat developed per unit mass in calorie\n",
-      "v = (J*10**7*h*2/0.9)**0.5;\t\t\t#velocity of bullet in cm/sec\n",
-      "\n",
-      "# Result\n",
-      "print 'the velocity of bullet is %.1e cm/sec'%(v)\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the velocity of bullet is 1.5e+04 cm/sec\n"
-       ]
-      }
-     ],
-     "prompt_number": 31
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.22 pageno : 51"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "# Variables\n",
-      "w = 5.0;\t\t\t#weight of lead ball in lb\n",
-      "cp = 0.032;\t\t\t#specific heat of lead in Btu/lbdeg.F\n",
-      "h = 50;\t\t\t#height at which ball thrown in feets\n",
-      "v = 20;\t\t\t#vertical speed in ft/sec\n",
-      "g = 32;\t\t\t#accelararion due to gravity in ft/sec**2\n",
-      "\n",
-      "# Calculations\n",
-      "u = (v**2)+2*g*h\n",
-      "ke = (w/2*(u));\t\t\t#kinetic energy of the ball at ground\n",
-      "T = ke/(2*32*778*w*cp);\t\t\t#rise of temperature in deg.F\n",
-      "\n",
-      "# Result\n",
-      "print 'the rise in temperature is %.1f deg.F'%(T)\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the rise in temperature is 1.1 deg.F\n"
-       ]
-      }
-     ],
-     "prompt_number": 32
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/TestContribution/ch3_1.ipynb b/TestContribution/ch3_1.ipynb
deleted file mode 100755
index 8becd279..00000000
--- a/TestContribution/ch3_1.ipynb
+++ /dev/null
@@ -1,941 +0,0 @@
-{
- "metadata": {
-  "name": ""
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 3 : The mechanical equivalent of  heat"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.1 pageno : 44"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "# Variables\n",
-      "m = 20;\t\t\t#calorimeter of water equivalent in gm\n",
-      "n = 1030;\t\t\t#weight of water in gm\n",
-      "p = 2;\t\t\t#no.of paddles\n",
-      "a = 10;\t\t\t#weight of each paddle in kg\n",
-      "s = 80;\t\t\t#dismath.tance between paddles in m\n",
-      "g = 980;\t\t\t#accelaration due to gravity in cm/sec**2\n",
-      "\n",
-      "# Calculations\n",
-      "E = (p*a*1000*g*s*100);\t\t\t#potential energy in dyne cm\n",
-      "T = (E)/(1050*4.18*10**7);\t\t\t#rise in temperature in deg.C\n",
-      "\n",
-      "# Result\n",
-      "print 'the rise in temperature of water is %3.2f deg.C'%(T)\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the rise in temperature of water is 3.57 deg.C\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.2 pageno : 45"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "# Variables\n",
-      "cp = 0.1;\t\t\t#specific heat of copper in kj/kg-K\n",
-      "w = 120;\t\t\t#weight of copper calorimeter in gm\n",
-      "a = 1400;\t\t\t#weight of paraffin oil in gm\n",
-      "cp1 = 0.6;\t\t\t#specific of parafin oil in kj/kg-K\n",
-      "b = 10**8;\t\t\t#force to rotate the paddle in dynes\n",
-      "T = 16;\t\t\t#rise in temperature in deg.C\n",
-      "n = 900;\t\t\t#no.of revolutions stirred \n",
-      "pi = 3.14;\t\t\t#value of pi\n",
-      "\n",
-      "# Calculations\n",
-      "c = 2*pi*b;\t\t\t#work done by a rotating paddle per rotation in dyne cm per rotation\n",
-      "d = c*n;\t\t\t#total work done in dyne cm \n",
-      "hc = w*cp*16;\t\t\t#heat gained by calorimeter in calories\n",
-      "hp = a*cp1*16;\t\t\t#heat gaained by paraffin oil in calories \n",
-      "J = d/(hc+hp);\t\t\t#mecanical equivalent of heat in erg/cal\n",
-      "\n",
-      "# Result\n",
-      "print 'mecanical equivalent of heat is %.2e erg/cal'%(J)\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "mecanical equivalent of heat is 4.15e+07 erg/cal\n"
-       ]
-      }
-     ],
-     "prompt_number": 2
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.3 pageno : 45"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "# Variables \n",
-      "cp = 0.12;\t\t\t#specific heat of iron in kj/kg-K\n",
-      "m = 25;\t\t\t#mass of iron in lb\n",
-      "h = 0.4;\t\t\t#horse power developed in 3 min\n",
-      "t = 3;\t\t\t#time taken to develop the horse power in min\n",
-      "T = 17;\t\t\t#raise in temp in deg.C\n",
-      "\n",
-      "# Calculations\n",
-      "w = h*33000*t;\t\t\t#total work done in ft-lb\n",
-      "H = m*cp*T;\t\t\t#aount of heat developed in B.Th.U\n",
-      "J = (w)/H;\t\t\t#the value of mechanical equivalent of heat\n",
-      "\n",
-      "# Result\n",
-      "print 'the mechanical equivalent of water is %3.1f ft-lb/B.Th.U'%(J)\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the mechanical equivalent of water is 776.5 ft-lb/B.Th.U\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.4 pageno : 45"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "# Variables \n",
-      "n = 2.;\t\t\t#no.of lead blocks\n",
-      "m = 210.;\t\t\t#mass of each lead block in gm\n",
-      "v = 20000.;\t\t\t#velocity of block relative to earth in cm/sec\n",
-      "J = 4.2*10**7;\t\t\t#mechanical equivalent of heat in ergs/calorie\n",
-      "cp = 0.03;\t\t\t#specific heat of lead in kj/kg-K\n",
-      "\n",
-      "# Calculations\n",
-      "E = (m*v**2)/2;\t\t\t#kinetic energy of each block in ergs\n",
-      "E2 = n*E;\t\t\t#total kinetic energy in ergs\n",
-      "T = E2/(J*m*n*cp);\t\t\t#mean rise in temperature in T\n",
-      "\n",
-      "# Result\n",
-      "print 'the mean rise in temperature is %3.1f deg.C'%(T)\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the mean rise in temperature is 158.7 deg.C\n"
-       ]
-      }
-     ],
-     "prompt_number": 4
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.5 pageno : 45"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "# Variables \n",
-      "h = 150;\t\t\t#height froom which ball fallen in ft\n",
-      "cp = 0.03;\t\t\t#specific heat of lead in kj/kg-K\n",
-      "J = 778;\t\t\t#mechanical equivalent of heat in ft lb/B.Th.U\n",
-      "\n",
-      "# Calculations\n",
-      "#work done in falling is equal to heat absorbed by the ball\n",
-      "T = 160./(J*cp)*(5./9);\t\t\t#the raise in temperature in T\n",
-      "\n",
-      "# Result\n",
-      "print 'the raise in temperature is %3.1f deg.C'%(T)\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the raise in temperature is 3.8 deg.C\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.6 pageno : 46"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "import math \n",
-      "# Variables \n",
-      "w = 26.6;\t\t\t#work done one horse in to raise the temperature in lb\n",
-      "T1 = 32.;\t\t\t#temperature at initial in deg.F\n",
-      "T2 = 212.;\t\t\t#temperature at final in deg.F\n",
-      "t = 2.5;\t\t\t#time to raise the tmperature in hrs\n",
-      "p = 25.;\t\t\t#percentage of heat lossed \n",
-      "\n",
-      "# Calculations\n",
-      "#only 75% of heat is utillised\n",
-      "x = w*180.*100.*778./((100-p)*150);\t\t\t#the rate at which horse worked\n",
-      "\n",
-      "# Result\n",
-      "print 'the rate at which horse worked is %3.0f ft-lb wt/min'%(x)\n",
-      "print \"Note : Answer in book is rounded off, Please calculate manually. This answer is accurate.\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the rate at which horse worked is 33112 ft-lb wt/min\n",
-        "Note : Answer in book is rounded off, Please calculate manually. This answer is accurate.\n"
-       ]
-      }
-     ],
-     "prompt_number": 7
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.7 pageno : 46"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "# Variables \n",
-      "l = 100.;\t\t\t#length of glass tube in cm\n",
-      "m = 500.;\t\t\t#mass of mercury in glass tube in gm\n",
-      "n = 20.;\t\t\t#number of times inverted i succession\n",
-      "cp = 0.03;\t\t\t#specific heat of mercury in cal/gm/deg.C\n",
-      "J = 4.2;\t\t\t#joule's equivalent in j/cal\n",
-      "g = 981.;\t\t\t#accelaration due to gravity in cm/s**2\n",
-      "\n",
-      "# Calculations\n",
-      "PE = m*g*l;\t\t\t#potential energy for each time in ergs\n",
-      "TE = PE*n;\t\t\t#total loss in ergs\n",
-      "T = TE/(m*cp*J*10**7);\t\t\t#rise in temperature in deg.C\n",
-      "#if T is the rise in temperature,then heat devoloped is m*cp*T\n",
-      "\n",
-      "# Result\n",
-      "print 'the rise in temperature is %3.2f deg.C'%(T)\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the rise in temperature is 1.56 deg.C\n"
-       ]
-      }
-     ],
-     "prompt_number": 8
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.8 page no : 46"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "\n",
-      "# Variables \n",
-      "d = 0.02;\t\t\t#diameter of the copper wire in cm\n",
-      "i = 1;\t\t\t#current in amp\n",
-      "T = 100;\t\t\t#maximum steady temperature in deg.C\n",
-      "r = 2.1;\t\t\t#resistance of the wire in ohm cm\n",
-      "J = 4.2;\t\t\t#mechanical equivalent of heat in j/cal\n",
-      "a = 3.14*d**2/4;\t\t\t#area of the copper wire in sq.cm\n",
-      "a2 = 1;\t\t\t#area of the copper surface in sq.cm\n",
-      "\n",
-      "# Calculations \n",
-      "l = 1/(2*3.14*d/2);\t\t\t#length corresponding to the area in cm\n",
-      "R = r*l/a;\t\t\t#resistance of the copper wire in ohm\n",
-      "w = R*a2**2;\t\t\t#work done in joule\n",
-      "h = w/J;\t\t\t#heat devoleped in cal\n",
-      "\n",
-      "# Result\n",
-      "print 'the heat developed is %.f calories'%(round(h,-1))\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the heat developed is 25360 calories\n"
-       ]
-      }
-     ],
-     "prompt_number": 11
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.9 pageno: 47"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "import math \n",
-      "\n",
-      "# Variables\n",
-      "h = 10000;\t\t\t#vertical height of water fall in cm\n",
-      "v = 5;\t\t\t    #volume disharged per sec in litres\n",
-      "J = 4.18;\t\t\t#joule's constant in j/cal\n",
-      "g = 981;\t\t\t#accelaration due to gravity in cm/sec**2\n",
-      "\n",
-      "# Calculations\n",
-      "m = v*1000;\t\t\t#mass of water disharged per sec in gm\n",
-      "w = m*h*g;\t\t\t#work done in falling through 100m in erg\n",
-      "H = (v*10**7 *g)/(J*10**7);\t#quantity of heat produced in cal\n",
-      "T = H/m;\t\t\t#rise in temperature in deg.C\n",
-      "\n",
-      "# Result\n",
-      "print 'the quantity of heat produced is %3f cal  \\\n",
-      "\\nthe rise in temperature is %3.2f deg.C'%(H,T)\n",
-      "\n",
-      "print \"Note : Answer for part A in book is wrong. Please calculate manually.\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the quantity of heat produced is 1173.444976 cal  \n",
-        "the rise in temperature is 0.23 deg.C\n",
-        "Note : Answer for part A in book is wrong. Please calculate manually.\n"
-       ]
-      }
-     ],
-     "prompt_number": 15
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.10 page no : 47"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "\n",
-      "# Variables \n",
-      "cp = 0.03;\t\t\t#specific heat of lead in kj/kg.k\n",
-      "v = 10000;\t\t\t#initial velocity of bullet in cm/sec\n",
-      "J = 4.2*10**7;\t\t\t#joules constant in ergs/cal\n",
-      "\n",
-      "# Calculations\n",
-      "ke = (v**2)/2;\t\t\t#kinetic energy of the bullet per unit mass in (cm/sec)**2\n",
-      "T = ke*95/(cp*J*100);\t\t\t#rise in temperature in deg.C\n",
-      "\n",
-      "# Result\n",
-      "print 'the rise in temperature is %3.1f deg.C'%(T)\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the rise in temperature is 37.7 deg.C\n"
-       ]
-      }
-     ],
-     "prompt_number": 16
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.11 page no : 47"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "# Variables \n",
-      "h = 5000.;\t\t\t#height of the niagara falls in cm\n",
-      "J = 4.2*10**7;\t\t#joules constant in ergs per cal\n",
-      "g = 981;\t\t\t#accelaration due to gravity in cm/sec**2\n",
-      "\n",
-      "#CALCULATIONS\n",
-      "w = h*g;\t\t\t#work done per unit mass in ergs/gn\n",
-      "T = w/J;\t\t\t#rise in temperature in deg.C\n",
-      "\n",
-      "# Result\n",
-      "print 'the rise in temperature is %3.2f deg.C'%(T)\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the rise in temperature is 0.12 deg.C\n"
-       ]
-      }
-     ],
-     "prompt_number": 17
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.12 page no : 48\n"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "import math \n",
-      "\n",
-      "# Variables \n",
-      "E1 = 3.75;\t\t\t#potential difference in v\n",
-      "E2 = 3.;\t\t\t#potential differnce in v\n",
-      "i1 = 2.5;\t\t\t#current in amp\n",
-      "i2 = 2;\t\t\t    #current in amp\n",
-      "T = 2.7;\t\t\t#the rise in temperature of the water in deg.C\n",
-      "m1 = 48.;\t\t\t#water flow rate at 3 volts in gm/min\n",
-      "m2 = 30.;\t\t\t#water flow rate at 3.75volts in gm/min\n",
-      "s = 1;\t\t\t    #specific heat of the water kj/kg-K\n",
-      "\n",
-      "# Calculations\n",
-      "J = (E1*i1-E2*i2)/(s*T*(m1-m2)/60);\t\t\t#the mechanical equivalent in j/cal\n",
-      "\n",
-      "# Result\n",
-      "print 'the mechanical equivalent is %3.3f j/cal'%(J)\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the mechanical equivalent is 4.167 j/cal\n"
-       ]
-      }
-     ],
-     "prompt_number": 18
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.13 page no : 48"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "\n",
-      "# Variables \n",
-      "R = 64*10**7;\t\t\t#mean radius of the earth in cm\n",
-      "cp = 0.15;\t\t\t#specific heat of earth in kj/kg-K\n",
-      "J = 4.2*10**7;\t\t\t#joules consmath.tant in erg/cal\n",
-      "\n",
-      "# Calculations\n",
-      "i = 2./5*R**2;\t\t\t#moment of inertia of the earth per unit mass in joules\n",
-      "w = (2*3.14)/(24*60*60);\t\t\t#angular velocity of the earth in rad/sec\n",
-      "T = (i*w**2)/(2*J*cp);\t\t\t#rise in temperature in deg.C\n",
-      "\n",
-      "# Result\n",
-      "print 'the rise in the temperature is %.1f deg C'%(T)\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the rise in the temperature is 68.7 deg C\n"
-       ]
-      }
-     ],
-     "prompt_number": 6
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.14 page no : 49"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "# Variables \n",
-      "cp = 1.25;\t\t\t#specific heat of helium inkj/kg-K\n",
-      "v = 1000;\t\t\t#volume of the gas in ml\n",
-      "w = 0.1785;\t\t\t#mass of the gas at N.T.P in gm\n",
-      "p = 76*13.6*981;\t#pressure of the gas at N.T.P in dynes\n",
-      "T = 273;\t\t\t#temperature at N.T.P in K\n",
-      "\n",
-      "# Calculations\n",
-      "V = 1000/w;\t\t\t#volume occupied by the 1gm of helium gas in cc\n",
-      "cv = cp/1.66;\t\t#specific heat at constant volume it is monatomuc gas kj/kg-K\n",
-      "r = p*V/T;\t\t\t#gas constant in cm**3.atm./K.mol\n",
-      "J = r/(cp-cv);\t\t#mechanical equivalent of heat in erg/cal\n",
-      "\n",
-      "# Result\n",
-      "print 'the mechanical equivalent of heat is %.2e ergs/calories'%(J)\n",
-      "print \"Note: answer slightly different because of rounding error.\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the mechanical equivalent of heat is 4.19e+07 ergs/calories\n",
-        "Note: answer slightly different because of rounding error.\n"
-       ]
-      }
-     ],
-     "prompt_number": 20
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "\n",
-      "Example 3.15 pageno : 49"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "# Variables \n",
-      "n = 1./273;     \t\t\t#coefficent of expaaansion of air\n",
-      "a = 0.001293;\t    \t\t#density of air in gm/cc\n",
-      "cp = 0.2389;\t\t    \t#specific heat at consmath.tant pressure in kj/kg.K\n",
-      "p = 76*13.6*981;\t\t\t#pressure at 0 deg.C in dynes\n",
-      "\n",
-      "# Calculations\n",
-      "J = (p*n)/(a*(cp-(cp/1.405)));\t\t\t#mechanical equivalent of heat\n",
-      "\n",
-      "# Result\n",
-      "print 'mechanical equivalent of heat is %.2e ergs/cal'%(J)\n",
-      "print \"Note: answer slightly different because of rounding error.\"\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "mechanical equivalent of heat is 4.17e+07 ergs/cal\n",
-        "Note: answer slightly different because of rounding error.\n"
-       ]
-      }
-     ],
-     "prompt_number": 22
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.16 pageno : 49"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "import math \n",
-      "# Variables \n",
-      "r = 120./60;\t\t\t#rate of flow of water in gm/sec\n",
-      "T1 = 27.30;\t\t\t#temperature at initial in deg.C\n",
-      "T2 = 33.75;\t\t\t#temperature at final in deg.C\n",
-      "v = 12.64;\t\t\t#potential drop in volts\n",
-      "s = 1.; \t\t\t#specific heat of water in kj/kg-K\n",
-      "i = 4.35;\t\t\t#current through the heating element in amp\n",
-      "\n",
-      "# Calculations\n",
-      "J = (v*i)/(r*s*(T2-T1));\t\t\t#the mechanical equivalent of heat in joule/calorie\n",
-      "\n",
-      "# Result\n",
-      "print 'the mechanical equivalent of heat is %3.2f j/cal'%(J)\n",
-      "print \"Note: answer slightly different because of rounding error.\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the mechanical equivalent of heat is 4.26 j/cal\n",
-        "Note: answer slightly different because of rounding error.\n"
-       ]
-      }
-     ],
-     "prompt_number": 24
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.17 page no : 50"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "\n",
-      "# Variables \n",
-      "cp = 6.865;\t\t\t#molar specific heat of hydrogen at consmath.tant pressure in kj/kg-K\n",
-      "cv = 4.880;\t\t\t#molar specific heat of hydrogen at consmath.tant volume in kj/kg-K\n",
-      "p = 1.013*10**6;\t\t\t#atmospheric pressure in dynes/cm**2\n",
-      "v = 22.4*10**3;\t\t\t#gram molar volume in ml\n",
-      "T = 273;\t\t\t#temperature at N.T.P in kelvins\n",
-      "\n",
-      "# Calculations\n",
-      "J = (p*v)/(T*(cp-cv));\t\t\t#mechanical equivalent of heat\n",
-      "\n",
-      "# Result\n",
-      "print 'the mechanical equivalent of heat is %.2e ergs/cal'%(J)\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the mechanical equivalent of heat is 4.19e+07 ergs/cal\n"
-       ]
-      }
-     ],
-     "prompt_number": 26
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.18 page no : 50"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "import math \n",
-      "# Variables\n",
-      "v = 1000.;\t\t\t#volume of hydrogen in ml\n",
-      "t = 273.;\t\t\t#tempature of hydrogen in kelvin\n",
-      "p = 76.;\t\t\t#pressure of hydrogen in mm of hg\n",
-      "w = 0.0896;\t\t\t#weigh of hydrogen in gm\n",
-      "cp = 3.409;\t\t\t#specific heat of hydogen in kj/kg-K\n",
-      "cv = 2.411;\t\t\t#specific heat of hydrogen in kj/kg-K\n",
-      "g = 981.;\t\t\t#accelaration due to gravity in cm/sec**2\n",
-      "a = 13.6;\t\t\t#density of mercury in gm/cm**2\n",
-      "\n",
-      "# Calculations\n",
-      "J = (p*v*g*a)/(w*t*(cp-cv));\t\t\t#mechanical equivalent of heat in ergs/cals\n",
-      "\n",
-      "# Result\n",
-      "print 'mechanical equivalent of heat is %.2e ergs/calorie'%(J)\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "mechanical equivalent of heat is 4.15e+07 ergs/calorie\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.19 page no : 50"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "# Variables\n",
-      "cp = 0.23;\t\t\t#specific heat at constant pressure in kj/kg-K\n",
-      "a = 1.18;\t\t\t#density of air in gm/lit\n",
-      "J = 4.2*10**7;\t\t\t#mechanical equivalent of heat in ergs/cal\n",
-      "t = 300;\t\t\t#temperature of air in kelvin\n",
-      "p = 73*13.6*981;\t\t\t#pressure of air in dynes\n",
-      "\t\t\t#cp-cv = (r/J) = pv/(tj)\n",
-      "\n",
-      "#CALCULATON\n",
-      "cv = cp-(p*1000/(a*t*J));\t\t\t#specific heat at constant volume in calories\n",
-      "\n",
-      "# Result\n",
-      "print 'the specific heat at constant volume is %.4f calories'%(cv)\n",
-      "print \"Note: answer slightly different because of rounding error.\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the specific heat at constant volume is 0.1645 calories\n",
-        "Note: answer slightly different because of rounding error.\n"
-       ]
-      }
-     ],
-     "prompt_number": 29
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.20 pageno : 51"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "# Variables\n",
-      "t1 = 0;\t\t\t#temperature of water in deg.C\n",
-      "t2 = 0;\t\t\t#temperature of ice in deg.C\n",
-      "J = 4.18*10**7;\t\t\t#the joules thomson coefficent in erg/cal\n",
-      "l = 80;\t\t\t#latent heat og fusion kj/kg\n",
-      "g = 981;\t\t\t#accelaration due to gravity in cm/sec**2\n",
-      " \n",
-      "# Calculations\n",
-      "h = l*J/(15*g);\t\t\t#height from which ice has fallen\n",
-      "\n",
-      "# Result\n",
-      "print 'the height from which ice has fallen is %.2e cm'%(h)\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the height from which ice has fallen is 2.27e+05 cm\n"
-       ]
-      }
-     ],
-     "prompt_number": 30
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.21 page no : 51"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "\n",
-      "# Variables\n",
-      "T = 80;\t\t\t#temperature of bullet in deg.C\n",
-      "cp = 0.03;\t\t\t#specific heat of lead in kj/kg-K\n",
-      "J = 4.2;\t\t\t#mechanical equivalent of heat in j/cal\n",
-      "\n",
-      "# Calculations\n",
-      "h = T*cp;\t\t\t#heat developed per unit mass in calorie\n",
-      "v = (J*10**7*h*2/0.9)**0.5;\t\t\t#velocity of bullet in cm/sec\n",
-      "\n",
-      "# Result\n",
-      "print 'the velocity of bullet is %.1e cm/sec'%(v)\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the velocity of bullet is 1.5e+04 cm/sec\n"
-       ]
-      }
-     ],
-     "prompt_number": 31
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.22 pageno : 51"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "# Variables\n",
-      "w = 5.0;\t\t\t#weight of lead ball in lb\n",
-      "cp = 0.032;\t\t\t#specific heat of lead in Btu/lbdeg.F\n",
-      "h = 50;\t\t\t#height at which ball thrown in feets\n",
-      "v = 20;\t\t\t#vertical speed in ft/sec\n",
-      "g = 32;\t\t\t#accelararion due to gravity in ft/sec**2\n",
-      "\n",
-      "# Calculations\n",
-      "u = (v**2)+2*g*h\n",
-      "ke = (w/2*(u));\t\t\t#kinetic energy of the ball at ground\n",
-      "T = ke/(2*32*778*w*cp);\t\t\t#rise of temperature in deg.F\n",
-      "\n",
-      "# Result\n",
-      "print 'the rise in temperature is %.1f deg.F'%(T)\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the rise in temperature is 1.1 deg.F\n"
-       ]
-      }
-     ],
-     "prompt_number": 32
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/TestContribution/ch3_2.ipynb b/TestContribution/ch3_2.ipynb
deleted file mode 100755
index 8becd279..00000000
--- a/TestContribution/ch3_2.ipynb
+++ /dev/null
@@ -1,941 +0,0 @@
-{
- "metadata": {
-  "name": ""
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 3 : The mechanical equivalent of  heat"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.1 pageno : 44"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "# Variables\n",
-      "m = 20;\t\t\t#calorimeter of water equivalent in gm\n",
-      "n = 1030;\t\t\t#weight of water in gm\n",
-      "p = 2;\t\t\t#no.of paddles\n",
-      "a = 10;\t\t\t#weight of each paddle in kg\n",
-      "s = 80;\t\t\t#dismath.tance between paddles in m\n",
-      "g = 980;\t\t\t#accelaration due to gravity in cm/sec**2\n",
-      "\n",
-      "# Calculations\n",
-      "E = (p*a*1000*g*s*100);\t\t\t#potential energy in dyne cm\n",
-      "T = (E)/(1050*4.18*10**7);\t\t\t#rise in temperature in deg.C\n",
-      "\n",
-      "# Result\n",
-      "print 'the rise in temperature of water is %3.2f deg.C'%(T)\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the rise in temperature of water is 3.57 deg.C\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.2 pageno : 45"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "# Variables\n",
-      "cp = 0.1;\t\t\t#specific heat of copper in kj/kg-K\n",
-      "w = 120;\t\t\t#weight of copper calorimeter in gm\n",
-      "a = 1400;\t\t\t#weight of paraffin oil in gm\n",
-      "cp1 = 0.6;\t\t\t#specific of parafin oil in kj/kg-K\n",
-      "b = 10**8;\t\t\t#force to rotate the paddle in dynes\n",
-      "T = 16;\t\t\t#rise in temperature in deg.C\n",
-      "n = 900;\t\t\t#no.of revolutions stirred \n",
-      "pi = 3.14;\t\t\t#value of pi\n",
-      "\n",
-      "# Calculations\n",
-      "c = 2*pi*b;\t\t\t#work done by a rotating paddle per rotation in dyne cm per rotation\n",
-      "d = c*n;\t\t\t#total work done in dyne cm \n",
-      "hc = w*cp*16;\t\t\t#heat gained by calorimeter in calories\n",
-      "hp = a*cp1*16;\t\t\t#heat gaained by paraffin oil in calories \n",
-      "J = d/(hc+hp);\t\t\t#mecanical equivalent of heat in erg/cal\n",
-      "\n",
-      "# Result\n",
-      "print 'mecanical equivalent of heat is %.2e erg/cal'%(J)\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "mecanical equivalent of heat is 4.15e+07 erg/cal\n"
-       ]
-      }
-     ],
-     "prompt_number": 2
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.3 pageno : 45"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "# Variables \n",
-      "cp = 0.12;\t\t\t#specific heat of iron in kj/kg-K\n",
-      "m = 25;\t\t\t#mass of iron in lb\n",
-      "h = 0.4;\t\t\t#horse power developed in 3 min\n",
-      "t = 3;\t\t\t#time taken to develop the horse power in min\n",
-      "T = 17;\t\t\t#raise in temp in deg.C\n",
-      "\n",
-      "# Calculations\n",
-      "w = h*33000*t;\t\t\t#total work done in ft-lb\n",
-      "H = m*cp*T;\t\t\t#aount of heat developed in B.Th.U\n",
-      "J = (w)/H;\t\t\t#the value of mechanical equivalent of heat\n",
-      "\n",
-      "# Result\n",
-      "print 'the mechanical equivalent of water is %3.1f ft-lb/B.Th.U'%(J)\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the mechanical equivalent of water is 776.5 ft-lb/B.Th.U\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.4 pageno : 45"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "# Variables \n",
-      "n = 2.;\t\t\t#no.of lead blocks\n",
-      "m = 210.;\t\t\t#mass of each lead block in gm\n",
-      "v = 20000.;\t\t\t#velocity of block relative to earth in cm/sec\n",
-      "J = 4.2*10**7;\t\t\t#mechanical equivalent of heat in ergs/calorie\n",
-      "cp = 0.03;\t\t\t#specific heat of lead in kj/kg-K\n",
-      "\n",
-      "# Calculations\n",
-      "E = (m*v**2)/2;\t\t\t#kinetic energy of each block in ergs\n",
-      "E2 = n*E;\t\t\t#total kinetic energy in ergs\n",
-      "T = E2/(J*m*n*cp);\t\t\t#mean rise in temperature in T\n",
-      "\n",
-      "# Result\n",
-      "print 'the mean rise in temperature is %3.1f deg.C'%(T)\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the mean rise in temperature is 158.7 deg.C\n"
-       ]
-      }
-     ],
-     "prompt_number": 4
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.5 pageno : 45"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "# Variables \n",
-      "h = 150;\t\t\t#height froom which ball fallen in ft\n",
-      "cp = 0.03;\t\t\t#specific heat of lead in kj/kg-K\n",
-      "J = 778;\t\t\t#mechanical equivalent of heat in ft lb/B.Th.U\n",
-      "\n",
-      "# Calculations\n",
-      "#work done in falling is equal to heat absorbed by the ball\n",
-      "T = 160./(J*cp)*(5./9);\t\t\t#the raise in temperature in T\n",
-      "\n",
-      "# Result\n",
-      "print 'the raise in temperature is %3.1f deg.C'%(T)\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the raise in temperature is 3.8 deg.C\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.6 pageno : 46"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "import math \n",
-      "# Variables \n",
-      "w = 26.6;\t\t\t#work done one horse in to raise the temperature in lb\n",
-      "T1 = 32.;\t\t\t#temperature at initial in deg.F\n",
-      "T2 = 212.;\t\t\t#temperature at final in deg.F\n",
-      "t = 2.5;\t\t\t#time to raise the tmperature in hrs\n",
-      "p = 25.;\t\t\t#percentage of heat lossed \n",
-      "\n",
-      "# Calculations\n",
-      "#only 75% of heat is utillised\n",
-      "x = w*180.*100.*778./((100-p)*150);\t\t\t#the rate at which horse worked\n",
-      "\n",
-      "# Result\n",
-      "print 'the rate at which horse worked is %3.0f ft-lb wt/min'%(x)\n",
-      "print \"Note : Answer in book is rounded off, Please calculate manually. This answer is accurate.\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the rate at which horse worked is 33112 ft-lb wt/min\n",
-        "Note : Answer in book is rounded off, Please calculate manually. This answer is accurate.\n"
-       ]
-      }
-     ],
-     "prompt_number": 7
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.7 pageno : 46"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "# Variables \n",
-      "l = 100.;\t\t\t#length of glass tube in cm\n",
-      "m = 500.;\t\t\t#mass of mercury in glass tube in gm\n",
-      "n = 20.;\t\t\t#number of times inverted i succession\n",
-      "cp = 0.03;\t\t\t#specific heat of mercury in cal/gm/deg.C\n",
-      "J = 4.2;\t\t\t#joule's equivalent in j/cal\n",
-      "g = 981.;\t\t\t#accelaration due to gravity in cm/s**2\n",
-      "\n",
-      "# Calculations\n",
-      "PE = m*g*l;\t\t\t#potential energy for each time in ergs\n",
-      "TE = PE*n;\t\t\t#total loss in ergs\n",
-      "T = TE/(m*cp*J*10**7);\t\t\t#rise in temperature in deg.C\n",
-      "#if T is the rise in temperature,then heat devoloped is m*cp*T\n",
-      "\n",
-      "# Result\n",
-      "print 'the rise in temperature is %3.2f deg.C'%(T)\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the rise in temperature is 1.56 deg.C\n"
-       ]
-      }
-     ],
-     "prompt_number": 8
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.8 page no : 46"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "\n",
-      "# Variables \n",
-      "d = 0.02;\t\t\t#diameter of the copper wire in cm\n",
-      "i = 1;\t\t\t#current in amp\n",
-      "T = 100;\t\t\t#maximum steady temperature in deg.C\n",
-      "r = 2.1;\t\t\t#resistance of the wire in ohm cm\n",
-      "J = 4.2;\t\t\t#mechanical equivalent of heat in j/cal\n",
-      "a = 3.14*d**2/4;\t\t\t#area of the copper wire in sq.cm\n",
-      "a2 = 1;\t\t\t#area of the copper surface in sq.cm\n",
-      "\n",
-      "# Calculations \n",
-      "l = 1/(2*3.14*d/2);\t\t\t#length corresponding to the area in cm\n",
-      "R = r*l/a;\t\t\t#resistance of the copper wire in ohm\n",
-      "w = R*a2**2;\t\t\t#work done in joule\n",
-      "h = w/J;\t\t\t#heat devoleped in cal\n",
-      "\n",
-      "# Result\n",
-      "print 'the heat developed is %.f calories'%(round(h,-1))\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the heat developed is 25360 calories\n"
-       ]
-      }
-     ],
-     "prompt_number": 11
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.9 pageno: 47"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "import math \n",
-      "\n",
-      "# Variables\n",
-      "h = 10000;\t\t\t#vertical height of water fall in cm\n",
-      "v = 5;\t\t\t    #volume disharged per sec in litres\n",
-      "J = 4.18;\t\t\t#joule's constant in j/cal\n",
-      "g = 981;\t\t\t#accelaration due to gravity in cm/sec**2\n",
-      "\n",
-      "# Calculations\n",
-      "m = v*1000;\t\t\t#mass of water disharged per sec in gm\n",
-      "w = m*h*g;\t\t\t#work done in falling through 100m in erg\n",
-      "H = (v*10**7 *g)/(J*10**7);\t#quantity of heat produced in cal\n",
-      "T = H/m;\t\t\t#rise in temperature in deg.C\n",
-      "\n",
-      "# Result\n",
-      "print 'the quantity of heat produced is %3f cal  \\\n",
-      "\\nthe rise in temperature is %3.2f deg.C'%(H,T)\n",
-      "\n",
-      "print \"Note : Answer for part A in book is wrong. Please calculate manually.\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the quantity of heat produced is 1173.444976 cal  \n",
-        "the rise in temperature is 0.23 deg.C\n",
-        "Note : Answer for part A in book is wrong. Please calculate manually.\n"
-       ]
-      }
-     ],
-     "prompt_number": 15
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.10 page no : 47"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "\n",
-      "# Variables \n",
-      "cp = 0.03;\t\t\t#specific heat of lead in kj/kg.k\n",
-      "v = 10000;\t\t\t#initial velocity of bullet in cm/sec\n",
-      "J = 4.2*10**7;\t\t\t#joules constant in ergs/cal\n",
-      "\n",
-      "# Calculations\n",
-      "ke = (v**2)/2;\t\t\t#kinetic energy of the bullet per unit mass in (cm/sec)**2\n",
-      "T = ke*95/(cp*J*100);\t\t\t#rise in temperature in deg.C\n",
-      "\n",
-      "# Result\n",
-      "print 'the rise in temperature is %3.1f deg.C'%(T)\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the rise in temperature is 37.7 deg.C\n"
-       ]
-      }
-     ],
-     "prompt_number": 16
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.11 page no : 47"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "# Variables \n",
-      "h = 5000.;\t\t\t#height of the niagara falls in cm\n",
-      "J = 4.2*10**7;\t\t#joules constant in ergs per cal\n",
-      "g = 981;\t\t\t#accelaration due to gravity in cm/sec**2\n",
-      "\n",
-      "#CALCULATIONS\n",
-      "w = h*g;\t\t\t#work done per unit mass in ergs/gn\n",
-      "T = w/J;\t\t\t#rise in temperature in deg.C\n",
-      "\n",
-      "# Result\n",
-      "print 'the rise in temperature is %3.2f deg.C'%(T)\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the rise in temperature is 0.12 deg.C\n"
-       ]
-      }
-     ],
-     "prompt_number": 17
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.12 page no : 48\n"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "import math \n",
-      "\n",
-      "# Variables \n",
-      "E1 = 3.75;\t\t\t#potential difference in v\n",
-      "E2 = 3.;\t\t\t#potential differnce in v\n",
-      "i1 = 2.5;\t\t\t#current in amp\n",
-      "i2 = 2;\t\t\t    #current in amp\n",
-      "T = 2.7;\t\t\t#the rise in temperature of the water in deg.C\n",
-      "m1 = 48.;\t\t\t#water flow rate at 3 volts in gm/min\n",
-      "m2 = 30.;\t\t\t#water flow rate at 3.75volts in gm/min\n",
-      "s = 1;\t\t\t    #specific heat of the water kj/kg-K\n",
-      "\n",
-      "# Calculations\n",
-      "J = (E1*i1-E2*i2)/(s*T*(m1-m2)/60);\t\t\t#the mechanical equivalent in j/cal\n",
-      "\n",
-      "# Result\n",
-      "print 'the mechanical equivalent is %3.3f j/cal'%(J)\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the mechanical equivalent is 4.167 j/cal\n"
-       ]
-      }
-     ],
-     "prompt_number": 18
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.13 page no : 48"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "\n",
-      "# Variables \n",
-      "R = 64*10**7;\t\t\t#mean radius of the earth in cm\n",
-      "cp = 0.15;\t\t\t#specific heat of earth in kj/kg-K\n",
-      "J = 4.2*10**7;\t\t\t#joules consmath.tant in erg/cal\n",
-      "\n",
-      "# Calculations\n",
-      "i = 2./5*R**2;\t\t\t#moment of inertia of the earth per unit mass in joules\n",
-      "w = (2*3.14)/(24*60*60);\t\t\t#angular velocity of the earth in rad/sec\n",
-      "T = (i*w**2)/(2*J*cp);\t\t\t#rise in temperature in deg.C\n",
-      "\n",
-      "# Result\n",
-      "print 'the rise in the temperature is %.1f deg C'%(T)\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the rise in the temperature is 68.7 deg C\n"
-       ]
-      }
-     ],
-     "prompt_number": 6
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.14 page no : 49"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "# Variables \n",
-      "cp = 1.25;\t\t\t#specific heat of helium inkj/kg-K\n",
-      "v = 1000;\t\t\t#volume of the gas in ml\n",
-      "w = 0.1785;\t\t\t#mass of the gas at N.T.P in gm\n",
-      "p = 76*13.6*981;\t#pressure of the gas at N.T.P in dynes\n",
-      "T = 273;\t\t\t#temperature at N.T.P in K\n",
-      "\n",
-      "# Calculations\n",
-      "V = 1000/w;\t\t\t#volume occupied by the 1gm of helium gas in cc\n",
-      "cv = cp/1.66;\t\t#specific heat at constant volume it is monatomuc gas kj/kg-K\n",
-      "r = p*V/T;\t\t\t#gas constant in cm**3.atm./K.mol\n",
-      "J = r/(cp-cv);\t\t#mechanical equivalent of heat in erg/cal\n",
-      "\n",
-      "# Result\n",
-      "print 'the mechanical equivalent of heat is %.2e ergs/calories'%(J)\n",
-      "print \"Note: answer slightly different because of rounding error.\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the mechanical equivalent of heat is 4.19e+07 ergs/calories\n",
-        "Note: answer slightly different because of rounding error.\n"
-       ]
-      }
-     ],
-     "prompt_number": 20
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "\n",
-      "Example 3.15 pageno : 49"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "# Variables \n",
-      "n = 1./273;     \t\t\t#coefficent of expaaansion of air\n",
-      "a = 0.001293;\t    \t\t#density of air in gm/cc\n",
-      "cp = 0.2389;\t\t    \t#specific heat at consmath.tant pressure in kj/kg.K\n",
-      "p = 76*13.6*981;\t\t\t#pressure at 0 deg.C in dynes\n",
-      "\n",
-      "# Calculations\n",
-      "J = (p*n)/(a*(cp-(cp/1.405)));\t\t\t#mechanical equivalent of heat\n",
-      "\n",
-      "# Result\n",
-      "print 'mechanical equivalent of heat is %.2e ergs/cal'%(J)\n",
-      "print \"Note: answer slightly different because of rounding error.\"\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "mechanical equivalent of heat is 4.17e+07 ergs/cal\n",
-        "Note: answer slightly different because of rounding error.\n"
-       ]
-      }
-     ],
-     "prompt_number": 22
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.16 pageno : 49"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "import math \n",
-      "# Variables \n",
-      "r = 120./60;\t\t\t#rate of flow of water in gm/sec\n",
-      "T1 = 27.30;\t\t\t#temperature at initial in deg.C\n",
-      "T2 = 33.75;\t\t\t#temperature at final in deg.C\n",
-      "v = 12.64;\t\t\t#potential drop in volts\n",
-      "s = 1.; \t\t\t#specific heat of water in kj/kg-K\n",
-      "i = 4.35;\t\t\t#current through the heating element in amp\n",
-      "\n",
-      "# Calculations\n",
-      "J = (v*i)/(r*s*(T2-T1));\t\t\t#the mechanical equivalent of heat in joule/calorie\n",
-      "\n",
-      "# Result\n",
-      "print 'the mechanical equivalent of heat is %3.2f j/cal'%(J)\n",
-      "print \"Note: answer slightly different because of rounding error.\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the mechanical equivalent of heat is 4.26 j/cal\n",
-        "Note: answer slightly different because of rounding error.\n"
-       ]
-      }
-     ],
-     "prompt_number": 24
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.17 page no : 50"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "\n",
-      "# Variables \n",
-      "cp = 6.865;\t\t\t#molar specific heat of hydrogen at consmath.tant pressure in kj/kg-K\n",
-      "cv = 4.880;\t\t\t#molar specific heat of hydrogen at consmath.tant volume in kj/kg-K\n",
-      "p = 1.013*10**6;\t\t\t#atmospheric pressure in dynes/cm**2\n",
-      "v = 22.4*10**3;\t\t\t#gram molar volume in ml\n",
-      "T = 273;\t\t\t#temperature at N.T.P in kelvins\n",
-      "\n",
-      "# Calculations\n",
-      "J = (p*v)/(T*(cp-cv));\t\t\t#mechanical equivalent of heat\n",
-      "\n",
-      "# Result\n",
-      "print 'the mechanical equivalent of heat is %.2e ergs/cal'%(J)\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the mechanical equivalent of heat is 4.19e+07 ergs/cal\n"
-       ]
-      }
-     ],
-     "prompt_number": 26
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.18 page no : 50"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "import math \n",
-      "# Variables\n",
-      "v = 1000.;\t\t\t#volume of hydrogen in ml\n",
-      "t = 273.;\t\t\t#tempature of hydrogen in kelvin\n",
-      "p = 76.;\t\t\t#pressure of hydrogen in mm of hg\n",
-      "w = 0.0896;\t\t\t#weigh of hydrogen in gm\n",
-      "cp = 3.409;\t\t\t#specific heat of hydogen in kj/kg-K\n",
-      "cv = 2.411;\t\t\t#specific heat of hydrogen in kj/kg-K\n",
-      "g = 981.;\t\t\t#accelaration due to gravity in cm/sec**2\n",
-      "a = 13.6;\t\t\t#density of mercury in gm/cm**2\n",
-      "\n",
-      "# Calculations\n",
-      "J = (p*v*g*a)/(w*t*(cp-cv));\t\t\t#mechanical equivalent of heat in ergs/cals\n",
-      "\n",
-      "# Result\n",
-      "print 'mechanical equivalent of heat is %.2e ergs/calorie'%(J)\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "mechanical equivalent of heat is 4.15e+07 ergs/calorie\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.19 page no : 50"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "# Variables\n",
-      "cp = 0.23;\t\t\t#specific heat at constant pressure in kj/kg-K\n",
-      "a = 1.18;\t\t\t#density of air in gm/lit\n",
-      "J = 4.2*10**7;\t\t\t#mechanical equivalent of heat in ergs/cal\n",
-      "t = 300;\t\t\t#temperature of air in kelvin\n",
-      "p = 73*13.6*981;\t\t\t#pressure of air in dynes\n",
-      "\t\t\t#cp-cv = (r/J) = pv/(tj)\n",
-      "\n",
-      "#CALCULATON\n",
-      "cv = cp-(p*1000/(a*t*J));\t\t\t#specific heat at constant volume in calories\n",
-      "\n",
-      "# Result\n",
-      "print 'the specific heat at constant volume is %.4f calories'%(cv)\n",
-      "print \"Note: answer slightly different because of rounding error.\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the specific heat at constant volume is 0.1645 calories\n",
-        "Note: answer slightly different because of rounding error.\n"
-       ]
-      }
-     ],
-     "prompt_number": 29
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.20 pageno : 51"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "# Variables\n",
-      "t1 = 0;\t\t\t#temperature of water in deg.C\n",
-      "t2 = 0;\t\t\t#temperature of ice in deg.C\n",
-      "J = 4.18*10**7;\t\t\t#the joules thomson coefficent in erg/cal\n",
-      "l = 80;\t\t\t#latent heat og fusion kj/kg\n",
-      "g = 981;\t\t\t#accelaration due to gravity in cm/sec**2\n",
-      " \n",
-      "# Calculations\n",
-      "h = l*J/(15*g);\t\t\t#height from which ice has fallen\n",
-      "\n",
-      "# Result\n",
-      "print 'the height from which ice has fallen is %.2e cm'%(h)\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the height from which ice has fallen is 2.27e+05 cm\n"
-       ]
-      }
-     ],
-     "prompt_number": 30
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.21 page no : 51"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "\n",
-      "# Variables\n",
-      "T = 80;\t\t\t#temperature of bullet in deg.C\n",
-      "cp = 0.03;\t\t\t#specific heat of lead in kj/kg-K\n",
-      "J = 4.2;\t\t\t#mechanical equivalent of heat in j/cal\n",
-      "\n",
-      "# Calculations\n",
-      "h = T*cp;\t\t\t#heat developed per unit mass in calorie\n",
-      "v = (J*10**7*h*2/0.9)**0.5;\t\t\t#velocity of bullet in cm/sec\n",
-      "\n",
-      "# Result\n",
-      "print 'the velocity of bullet is %.1e cm/sec'%(v)\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the velocity of bullet is 1.5e+04 cm/sec\n"
-       ]
-      }
-     ],
-     "prompt_number": 31
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.22 pageno : 51"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "# Variables\n",
-      "w = 5.0;\t\t\t#weight of lead ball in lb\n",
-      "cp = 0.032;\t\t\t#specific heat of lead in Btu/lbdeg.F\n",
-      "h = 50;\t\t\t#height at which ball thrown in feets\n",
-      "v = 20;\t\t\t#vertical speed in ft/sec\n",
-      "g = 32;\t\t\t#accelararion due to gravity in ft/sec**2\n",
-      "\n",
-      "# Calculations\n",
-      "u = (v**2)+2*g*h\n",
-      "ke = (w/2*(u));\t\t\t#kinetic energy of the ball at ground\n",
-      "T = ke/(2*32*778*w*cp);\t\t\t#rise of temperature in deg.F\n",
-      "\n",
-      "# Result\n",
-      "print 'the rise in temperature is %.1f deg.F'%(T)\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the rise in temperature is 1.1 deg.F\n"
-       ]
-      }
-     ],
-     "prompt_number": 32
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/TestContribution/chapterno1.ipynb b/TestContribution/chapterno1.ipynb
deleted file mode 100755
index 5ff2285e..00000000
--- a/TestContribution/chapterno1.ipynb
+++ /dev/null
@@ -1,126 +0,0 @@
-{


- "metadata": {


-  "name": "",


-  "signature": "sha256:a1ed470be69235951f179c73fc3f7daca02bf5e071f528ddce3fb4f1444cb8ef"


- },


- "nbformat": 3,


- "nbformat_minor": 0,


- "worksheets": [


-  {


-   "cells": [


-    {


-     "cell_type": "heading",


-     "level": 1,


-     "metadata": {},


-     "source": [


-      "Chapter 1: INTRODUCTORY DIGITAL CONCEPTS"


-     ]


-    },


-    {


-     "cell_type": "heading",


-     "level": 2,


-     "metadata": {},


-     "source": [


-      "Example 1-1,Page No-6"


-     ]


-    },


-    {


-     "cell_type": "code",


-     "collapsed": false,


-     "input": [


-      "#Variable Declaration\n",


-      "T=10*10**-3\n",


-      "tw=1*10**-3\n",


-      "\n",


-      "#Calculations\n",


-      "#Part A\n",


-      "f=1/T\n",


-      "\n",


-      "#Part C\n",


-      "Duty_Cycle=(tw/T)*100\n",


-      "\n",


-      "\n",


-      "#Results\n",


-      "print\"The Period is measured from the edge of the next pulse. In this case T is measured from leading edge to leading edge,as indicated.T equals 10*10^-3\"\n",


-      "print\"f=\",f,\"Hz\"\n",


-      "print\"Duty Cycle=\",Duty_Cycle,\"%\""


-     ],


-     "language": "python",


-     "metadata": {},


-     "outputs": [


-      {


-       "output_type": "stream",


-       "stream": "stdout",


-       "text": [


-        "The Period is measured from the edge of the next pulse. In this case T is measured from leading edge to leading edge,as indicated.T equals 10*10^-3\n",


-        "f= 100.0 Hz\n",


-        "Duty Cycle= 10.0 %\n"


-       ]


-      }


-     ],


-     "prompt_number": 5


-    },


-    {


-     "cell_type": "heading",


-     "level": 2,


-     "metadata": {},


-     "source": [


-      "Example 1-2, Page No-8"


-     ]


-    },


-    {


-     "cell_type": "code",


-     "collapsed": false,


-     "input": [


-      "#Variable Declaration\n",


-      "f=100*10**-3\n",


-      "time=8\n",


-      "T=1/f\n",


-      "print\"Since the frequency of the clock is 100kHz,the period is\",T,\"usec\"\n",


-      "print\"It takes 10*10**-6to transfer each bit in the waveform.The total transfer time for 8 bits is time\"\n",


-      "print\"Time is\",time,\"usec\"\n",


-      "\n",


-      "print\"To detrmine the sequence of bits,examine the waveform during each bit time.If waveform A is HIGH during the bit time, a 1 is transferred. If waveform A is LOW during the bit time,a0 is transferred. The bit sequence is illustrated .The left mosst bit is the first to be transferred.\"\n",


-      "\n",


-      "print\"A parallel transfer would take 10*10**-6 for all eight bits.\"\n",


-      "    \n"


-     ],


-     "language": "python",


-     "metadata": {},


-     "outputs": [


-      {


-       "output_type": "stream",


-       "stream": "stdout",


-       "text": [


-        "Since the frequency of the clock is 100kHz,the period is 10.0 usec\n",


-        "It takes 10*10**-6to transfer each bit in the waveform.The total transfer time for 8 bits is time\n",


-        "Time is 8 usec\n",


-        "To detrmine the sequence of bits,examine the waveform during each bit time.If waveform A is HIGH during the bit time, a 1 is transferred. If waveform A is LOW during the bit time,a0 is transferred. The bit sequence is illustrated .The left mosst bit is the first to be transferred.\n",


-        "A parallel transfer would take 10*10**-6 for all eight bits.\n"


-       ]


-      }


-     ],


-     "prompt_number": 14


-    },


-    {


-     "cell_type": "code",


-     "collapsed": false,


-     "input": [],


-     "language": "python",


-     "metadata": {},


-     "outputs": [],


-     "prompt_number": 8


-    },


-    {


-     "cell_type": "code",


-     "collapsed": false,


-     "input": [],


-     "language": "python",


-     "metadata": {},


-     "outputs": []


-    }


-   ],


-   "metadata": {}


-  }


- ]


-}
\ No newline at end of file
diff --git a/TestContribution/exampleCount.py b/TestContribution/exampleCount.py
deleted file mode 100755
index f9c17511..00000000
--- a/TestContribution/exampleCount.py
+++ /dev/null
@@ -1,27 +0,0 @@
-import json
-import os
-import re
-
-class info:
-    notebook = ''
-    examples = []
-notebooks = os.listdir('.')
-notebooks = sorted(notebooks)
-print notebooks
-
-total = 0
-
-for i in range(len(notebooks)):
-    ch_examples = 0
-    if notebooks[i].endswith(".ipynb"):
-        f = open(notebooks[i],'r')
-        data = json.load(f)
-        for dic in data["worksheets"][0]["cells"][0:]:
-            if "level" in dic and dic["level"] == 2:
-                ch_examples += 1
-        total += ch_examples
-        print i, " :  " , ch_examples
-        
-                
-
-print "Total Examples : " , total
diff --git a/TestContribution/screenshots/State_Direction.png b/TestContribution/screenshots/State_Direction.png
deleted file mode 100755
index 145f4da6..00000000
--- a/TestContribution/screenshots/State_Direction.png
+++ /dev/null
diff --git a/TestContribution/screenshots/State_Direction_1.png b/TestContribution/screenshots/State_Direction_1.png
deleted file mode 100755
index 145f4da6..00000000
--- a/TestContribution/screenshots/State_Direction_1.png
+++ /dev/null
diff --git a/TestContribution/screenshots/State_Direction_10.png b/TestContribution/screenshots/State_Direction_10.png
deleted file mode 100755
index 145f4da6..00000000
--- a/TestContribution/screenshots/State_Direction_10.png
+++ /dev/null
diff --git a/TestContribution/screenshots/State_Direction_11.png b/TestContribution/screenshots/State_Direction_11.png
deleted file mode 100755
index 145f4da6..00000000
--- a/TestContribution/screenshots/State_Direction_11.png
+++ /dev/null
diff --git a/TestContribution/screenshots/State_Direction_12.png b/TestContribution/screenshots/State_Direction_12.png
deleted file mode 100755
index 145f4da6..00000000
--- a/TestContribution/screenshots/State_Direction_12.png
+++ /dev/null
diff --git a/TestContribution/screenshots/State_Direction_13.png b/TestContribution/screenshots/State_Direction_13.png
deleted file mode 100755
index 145f4da6..00000000
--- a/TestContribution/screenshots/State_Direction_13.png
+++ /dev/null
diff --git a/TestContribution/screenshots/State_Direction_14.png b/TestContribution/screenshots/State_Direction_14.png
deleted file mode 100755
index 145f4da6..00000000
--- a/TestContribution/screenshots/State_Direction_14.png
+++ /dev/null
diff --git a/TestContribution/screenshots/State_Direction_15.png b/TestContribution/screenshots/State_Direction_15.png
deleted file mode 100755
index 145f4da6..00000000
--- a/TestContribution/screenshots/State_Direction_15.png
+++ /dev/null
diff --git a/TestContribution/screenshots/State_Direction_16.png b/TestContribution/screenshots/State_Direction_16.png
deleted file mode 100755
index 145f4da6..00000000
--- a/TestContribution/screenshots/State_Direction_16.png
+++ /dev/null
diff --git a/TestContribution/screenshots/State_Direction_17.png b/TestContribution/screenshots/State_Direction_17.png
deleted file mode 100755
index 145f4da6..00000000
--- a/TestContribution/screenshots/State_Direction_17.png
+++ /dev/null
diff --git a/TestContribution/screenshots/State_Direction_18.png b/TestContribution/screenshots/State_Direction_18.png
deleted file mode 100755
index 145f4da6..00000000
--- a/TestContribution/screenshots/State_Direction_18.png
+++ /dev/null
diff --git a/TestContribution/screenshots/State_Direction_19.png b/TestContribution/screenshots/State_Direction_19.png
deleted file mode 100755
index 145f4da6..00000000
--- a/TestContribution/screenshots/State_Direction_19.png
+++ /dev/null
diff --git a/TestContribution/screenshots/State_Direction_2.png b/TestContribution/screenshots/State_Direction_2.png
deleted file mode 100755
index 145f4da6..00000000
--- a/TestContribution/screenshots/State_Direction_2.png
+++ /dev/null
diff --git a/TestContribution/screenshots/State_Direction_20.png b/TestContribution/screenshots/State_Direction_20.png
deleted file mode 100755
index 145f4da6..00000000
--- a/TestContribution/screenshots/State_Direction_20.png
+++ /dev/null
diff --git a/TestContribution/screenshots/State_Direction_3.png b/TestContribution/screenshots/State_Direction_3.png
deleted file mode 100755
index 145f4da6..00000000
--- a/TestContribution/screenshots/State_Direction_3.png
+++ /dev/null
diff --git a/TestContribution/screenshots/State_Direction_4.png b/TestContribution/screenshots/State_Direction_4.png
deleted file mode 100755
index 145f4da6..00000000
--- a/TestContribution/screenshots/State_Direction_4.png
+++ /dev/null
diff --git a/TestContribution/screenshots/State_Direction_5.png b/TestContribution/screenshots/State_Direction_5.png
deleted file mode 100755
index 145f4da6..00000000
--- a/TestContribution/screenshots/State_Direction_5.png
+++ /dev/null
diff --git a/TestContribution/screenshots/State_Direction_6.png b/TestContribution/screenshots/State_Direction_6.png
deleted file mode 100755
index 145f4da6..00000000
--- a/TestContribution/screenshots/State_Direction_6.png
+++ /dev/null
diff --git a/TestContribution/screenshots/State_Direction_7.png b/TestContribution/screenshots/State_Direction_7.png
deleted file mode 100755
index 145f4da6..00000000
--- a/TestContribution/screenshots/State_Direction_7.png
+++ /dev/null
diff --git a/TestContribution/screenshots/State_Direction_8.png b/TestContribution/screenshots/State_Direction_8.png
deleted file mode 100755
index 145f4da6..00000000
--- a/TestContribution/screenshots/State_Direction_8.png
+++ /dev/null
diff --git a/TestContribution/screenshots/State_Direction_9.png b/TestContribution/screenshots/State_Direction_9.png
deleted file mode 100755
index 145f4da6..00000000
--- a/TestContribution/screenshots/State_Direction_9.png
+++ /dev/null
diff --git a/Testing_Textbook_Companion_Directory/chapter2.ipynb b/Testing_Textbook_Companion_Directory/chapter2.ipynb
deleted file mode 100755
index 33489895..00000000
--- a/Testing_Textbook_Companion_Directory/chapter2.ipynb
+++ /dev/null
@@ -1,285 +0,0 @@
-{
- "metadata": {
-  "name": "",
-  "signature": "sha256:4b491165aaa84eef66101894e30c202e368215710941e1135ee996c3417298e7"
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 2: Types of Energy"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.1, page no. 19"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "import scipy.integrate\n",
-      "\n",
-      "#initialization\n",
-      "k = 20                        #lb/in\n",
-      "x = 3                         #in\n",
-      "\n",
-      "#calculation\n",
-      "def fun(x):\n",
-      "    y = k*x\n",
-      "    return y\n",
-      "\n",
-      "w = scipy.integrate.quadrature(fun, 0.0, 3.0)\n",
-      "\n",
-      "#result\n",
-      "print \"Work done = %d in-lb\" %(round(w[0]))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Work done = 90 in-lb\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.2, page no. 22"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "import scipy.integrate\n",
-      "\n",
-      "#initialization\n",
-      "w   =   0.1                           #lbm\n",
-      "Pv   =   30000                        #ft-lb/lbm\n",
-      "v1   =   14.0                         #ft^3 /lbm\n",
-      "v2   =   3.0                          #ft^3/lbm\n",
-      "\n",
-      "#calculation\n",
-      "def func(v):\n",
-      "    W   =   Pv/v\n",
-      "    return W\n",
-      "\n",
-      "temp   =   scipy.integrate.quadrature(func, v1, v2,)\n",
-      "Work   =   w * temp[0]\n",
-      "\n",
-      "#result\n",
-      "#Answer varies a bit from the text due to rounding off of log value\n",
-      "print \"Work done   =   %d ft-lb\" %Work"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Work done   =   -4621 ft-lb\n"
-       ]
-      }
-     ],
-     "prompt_number": 2
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.3, page no. 27"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "import scipy.integrate\n",
-      "\n",
-      "#initialization of variables\n",
-      "T1 = 500.0                          #R\n",
-      "T2 = 1000.0                         #R\n",
-      "w = 2.0                             #lbm\n",
-      "\n",
-      "#calculations\n",
-      "def c(T):\n",
-      "    cp=0.282+0.00046*T\n",
-      "    return cp\n",
-      "\n",
-      "Q = scipy.integrate.quadrature(c, T1, T2,)[0]\n",
-      "Heat = Q*w\n",
-      "\n",
-      "#results\n",
-      "print \"Heat flow = %d B\" %(Heat)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Heat flow = 626 B\n"
-       ]
-      }
-     ],
-     "prompt_number": 9
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.4, page no. 29"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "import scipy.integrate\n",
-      "\n",
-      "#initialization\n",
-      "T1 = 500.0                      #R\n",
-      "T2 = 1060.0                     #R\n",
-      "w = 1                           #lbm\n",
-      "\n",
-      "#calculation\n",
-      "def v(T):\n",
-      "    cv = 0.258-120/T +40000/T**2\n",
-      "    return cv\n",
-      "\n",
-      "Q = scipy.integrate.quadrature(v, T1, T2,)[0]\n",
-      "cvm=Q/(T2-T1)\n",
-      "\n",
-      "#result\n",
-      "print \"The amount of heat: \", round(Q,1), \"B/lbm\"\n",
-      "print \"Mean specific heat = %.3f B/lbm F\" %cvm"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The amount of heat:  96.6 B/lbm\n",
-        "Mean specific heat = 0.172 B/lbm F\n"
-       ]
-      }
-     ],
-     "prompt_number": 12
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.5, page no. 31"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "#initialization\n",
-      "w=1                         #lbm\n",
-      "Sw=0.3120                   #B/lbm R\n",
-      "Ss=1.7566                   #B/lb R\n",
-      "T=672                       #R\n",
-      "\n",
-      "#calculation\n",
-      "Q=T*(Ss-Sw)\n",
-      "\n",
-      "\n",
-      "#result\n",
-      "print \"Latent heat of water = %d B/lbm\" %Q"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Latent heat of water = 970 B/lbm\n"
-       ]
-      }
-     ],
-     "prompt_number": 13
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.6, page no. 31"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "import scipy.integrate\n",
-      "\n",
-      "#initialization\n",
-      "w=1                         #lbm\n",
-      "T1=492                      #R\n",
-      "T2=672                      #R\n",
-      "cp=1                        #B/lbm F\n",
-      "\n",
-      "#calculation\n",
-      "dQ=cp*(T2-T1)\n",
-      "def ds(T):\n",
-      "    s=1/T\n",
-      "    return s\n",
-      "\n",
-      "entropy = scipy.integrate.quadrature(ds, T1, T2,)[0]\n",
-      "\n",
-      "#results\n",
-      "print \"Entropy change = \", round(entropy, 3), \"B/lbm R\" "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Entropy change =  0.312 B/lbm R\n"
-       ]
-      }
-     ],
-     "prompt_number": 15
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Testing_Textbook_Companion_Directory/chapter5.ipynb b/Testing_Textbook_Companion_Directory/chapter5.ipynb
deleted file mode 100755
index bf944c6e..00000000
--- a/Testing_Textbook_Companion_Directory/chapter5.ipynb
+++ /dev/null
@@ -1,171 +0,0 @@
-{
- "metadata": {
-  "name": "",
-  "signature": "sha256:080ddee320ed2e8325a1bba2bf7e96e362906d7bc4b7f00bae6953ceccc830a0"
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 5: The Second Law of Thermodynamics"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.1, page no. 87"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "#initilisation\n",
-      "Tr = 540.0                      #R\n",
-      "Te = 2000.0                     #R\n",
-      "m = 200.0                       #B/lbm\n",
-      "\n",
-      "#calculation\n",
-      "eta = 1-(Tr/Te)\n",
-      "Qr = m*(1-eta)\n",
-      "\n",
-      "\n",
-      "#result\n",
-      "print \"Thermal efficiency is \", eta*100, \"%\"\n",
-      "print \"Heat rejected = %d B/lbm\" %Qr"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Thermal efficiency is  73.0 %\n",
-        "Heat rejected = 54 B/lbm\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.2, page no. 90"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "import scipy.integrate\n",
-      "\n",
-      "#initilisation\n",
-      "cv=0.171                    #B/lbm F\n",
-      "T2=580                      #F\n",
-      "T1=520                      #F\n",
-      "\n",
-      "#calculation\n",
-      "def fun(T):\n",
-      "    cp=cv/T\n",
-      "    return cp\n",
-      "\n",
-      "ds = scipy.integrate.quadrature(fun, T1, T2)[0]\n",
-      "\n",
-      "#result\n",
-      "print \"Change in entropy = %.4f B/lbm R\" %ds"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Change in entropy = 0.0187 B/lbm R\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.3, page no. 95"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "import scipy.integrate\n",
-      "\n",
-      "#initilisation\n",
-      "\n",
-      "Q = 100.0                         #B/lbm\n",
-      "Cp = 0.24                         #B/lbm F\n",
-      "T1 = 70.0+460.0                   #R\n",
-      "T2 = 550.0+460.0                  #R\n",
-      "Ts = 50.0+460.0                   #R\n",
-      "\n",
-      "#calculation\n",
-      "def fun(T):\n",
-      "    cp = Cp/T\n",
-      "    return cp\n",
-      "    \n",
-      "ds1 = scipy.integrate.quadrature(fun, T1, T2)[0]\n",
-      "Tf  = Q/Cp + T1\n",
-      "ds2 = scipy.integrate.quadrature(fun, T1, Tf)[0]\n",
-      "Qr = Ts*(ds2)\n",
-      "Qa = Q-Qr\n",
-      "Qun = Ts*(ds1)\n",
-      "Qa2 = Q-Qun\n",
-      "\n",
-      "#result\n",
-      "print \"Case 1\"\n",
-      "print \"Change in entropy = %.4f B/lbm R\" %ds1\n",
-      "print \"case 2\"\n",
-      "print \"Entropy change = %.4f B/lbm R\" %ds2\n",
-      "print \"Available energy = %.1f B/lbm\" %Qa\n",
-      "print \"case 3\"\n",
-      "print \"Available energy = %.1f B/lbm\" %Qa2"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Case 1\n",
-        "Change in entropy = 0.1548 B/lbm R\n",
-        "case 2\n",
-        "Entropy change = 0.1392 B/lbm R\n",
-        "Available energy = 29.0 B/lbm\n",
-        "case 3\n",
-        "Available energy = 21.1 B/lbm\n"
-       ]
-      }
-     ],
-     "prompt_number": 6
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Testing_Textbook_Companion_Directory/screenshots/energy.png b/Testing_Textbook_Companion_Directory/screenshots/energy.png
deleted file mode 100755
index 67a7242e..00000000
--- a/Testing_Textbook_Companion_Directory/screenshots/energy.png
+++ /dev/null
diff --git a/Testing_Textbook_Companion_Directory/screenshots/internal-energy.png b/Testing_Textbook_Companion_Directory/screenshots/internal-energy.png
deleted file mode 100755
index e2055783..00000000
--- a/Testing_Textbook_Companion_Directory/screenshots/internal-energy.png
+++ /dev/null
diff --git a/Testing_Textbook_Companion_Directory/screenshots/temprature.png b/Testing_Textbook_Companion_Directory/screenshots/temprature.png
deleted file mode 100755
index 24557a42..00000000
--- a/Testing_Textbook_Companion_Directory/screenshots/temprature.png
+++ /dev/null
diff --git a/Testing_the_interface/README.txt b/Testing_the_interface/README.txt
deleted file mode 100755
index 110efe0b..00000000
--- a/Testing_the_interface/README.txt
+++ /dev/null
@@ -1,10 +0,0 @@
-Contributed By: Test User
-Course: mca
-College/Institute/Organization: Indian Institute of Technology
-Department/Designation: Aerospace Engineering
-Book Title: Testing the interface
-Author: Myself
-Publisher: Don't Know
-Year of publication: 2020
-Isbn: 2233445566
-Edition: 2nd
\ No newline at end of file
diff --git a/Testing_the_interface/chapter1.ipynb b/Testing_the_interface/chapter1.ipynb
deleted file mode 100755
index cf45a409..00000000
--- a/Testing_the_interface/chapter1.ipynb
+++ /dev/null
@@ -1,423 +0,0 @@
-{
- "metadata": {
-  "name": ""
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 1: Tension Comprssion and Shear"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.1, page no. 9"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "Find compressive stress and strain in the post\n",
-      "\"\"\"\n",
-      "\n",
-      "import math\n",
-      "\n",
-      "#initialisation\n",
-      "\n",
-      "d_1 = 4                 # inner diameter (inch)\n",
-      "d_2 = 4.5               #outer diameter (inch)\n",
-      "P = 26000               # pressure in pound\n",
-      "L = 16                  # Length of cylinder (inch)\n",
-      "my_del = 0.012             # shortening of post (inch)\n",
-      "\n",
-      "#calculation\n",
-      "A = (math.pi/4)*((d_2**2)-(d_1**2))     #Area (inch^2)\n",
-      "s = P/A                                 # stress\n",
-      "\n",
-      "print \"compressive stress in the post is \", round(s), \"psi\"\n",
-      "\n",
-      "e = my_del/L                            # strain\n",
-      "\n",
-      "print \"compressive strain in the post is %e\" %e"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "compressive stress in the post is  7789.0 psi\n",
-        "compressive strain in the post is 7.500000e-04\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.2, page no. 10"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "formula for maximum stress & calculating maximum stress\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "W = 1500                    # weight (Newton)\n",
-      "d = 0.008                   #diameter(meter) \n",
-      "g = 77000                   # Weight density of steel\n",
-      "L = 40                      # Length of bar (m)\n",
-      "\n",
-      "#calculation\n",
-      "\n",
-      "A = (math.pi/4)*(d**2)      # Area\n",
-      "s_max = (1500/A) + (g*L)    # maximum stress\n",
-      "\n",
-      "#result\n",
-      "print \"Therefore the maximum stress in the rod is \", round(s_max,1), \"Pa\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Therefore the maximum stress in the rod is  32921551.8 Pa\n"
-       ]
-      }
-     ],
-     "prompt_number": 16
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.3. page no. 26"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculating change in lenght of pipe, strain in pipe, increase in diameter & increase in wall thickness\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "d1 = 4.5                            # diameter in inch\n",
-      "d2 = 6                              # diameter in inch\n",
-      "A = (math.pi/4)*((d2**2)-(d1**2))   # Area\n",
-      "P = 140                             # pressure in K\n",
-      "s = -P/A                            # stress (compression)\n",
-      "E = 30000                           # young's modulus in Ksi\n",
-      "e = s/E                             # strain\n",
-      "\n",
-      "#calculation\n",
-      "\n",
-      "# Part (a)\n",
-      "my_del = e*4*12                        # del = e*L \n",
-      "print \"Change in length of the pipe is\", round(my_del,3), \"inch\"\n",
-      "\n",
-      "# Part (b)\n",
-      "v = 0.30                            # Poissio's ratio\n",
-      "e_ = -(v*e)\n",
-      "print \"Lateral strain in the pipe is %e\" %e_\n",
-      "\n",
-      "# Part (c)\n",
-      "del_d2 = e_*d2 \n",
-      "del_d1 = e_*d1\n",
-      "print \"Increase in the inner diameter is \", round(del_d1,6), \"inch\"\n",
-      "\n",
-      "# Part (d)\n",
-      "t = 0.75\n",
-      "del_t = e_*t\n",
-      "print \"Increase in the wall thicness is %f\" %del_t, \"inch\"\n",
-      "del_t1 = (del_d2-del_d1)/2 \n",
-      "print \"del_t1 = del_t\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Change in length of the pipe is -0.018 inch\n",
-        "Lateral strain in the pipe is 1.131768e-04\n",
-        "Increase in the inner diameter is  0.000509 inch\n",
-        "Increase in the wall thicness is 0.000085 inch\n",
-        "del_t1 = del_t\n"
-       ]
-      }
-     ],
-     "prompt_number": 7
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.4, page no. 35"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculate average shear stress and compressive stress\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "d = 0.02                            # diameter in m\n",
-      "t = 0.008                           # thickness in m\n",
-      "A = math.pi*d*t                     # shear area\n",
-      "P = 110000                          # prassure in Newton\n",
-      "\n",
-      "#calculation\n",
-      "A1 = (math.pi/4)*(d**2)             # Punch area\n",
-      "t_aver = P/A                        # Average shear stress \n",
-      "\n",
-      "\n",
-      "print \"Average shear stress in the plate is \", t_aver, \"Pa\"\n",
-      "s_c = P/A1  # compressive stress\n",
-      "print \"Average compressive stress in the plate is \", s_c, \"Pa\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Average shear stress in the plate is  218838046.751 Pa\n",
-        "Average compressive stress in the plate is  350140874.802 Pa\n"
-       ]
-      }
-     ],
-     "prompt_number": 37
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Eample 1.5, page no. 36"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculate bearing stress, shear stress in pin,\n",
-      "bearing stress between pin and gussets,\n",
-      "shear stress in anchor bolts\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "\n",
-      "P = 12.0                              # Pressure in K\n",
-      "t = 0.375                           # thickness of wall in inch\n",
-      "theta = 40.0                          # angle in degree\n",
-      "d_pin = 0.75                        # diameter of pin in inch\n",
-      "t_G = 0.625                         # thickness of gusset in inch\n",
-      "t_B = 0.375                         #thickness of base plate in inch\n",
-      "d_b = 0.50                          # diameter of bolt in inch\n",
-      "\n",
-      "#calculation\n",
-      "\n",
-      "#Part (a)\n",
-      "s_b1 = P/(2*t*d_pin)                  # bearing stress\n",
-      "print \"Bearing stress between strut and pin\", round(s_b1,1), \"ksi\"\n",
-      "\n",
-      "#Part (b)\n",
-      "t_pin = (4*P)/(2*math.pi*(d_pin**2))  # average shear stress in the \n",
-      "print \"Shear stress in pin is \", round(t_pin,1), \"ksi\"\n",
-      "\n",
-      "# Part (c)\n",
-      "s_b2 = P/(2*t_G*d_pin)                # bearing stress between pin and gusset\n",
-      "print \"Bearing stress between pin and gussets is\", s_b2, \"ksi\"\n",
-      "\n",
-      "# Part (d)\n",
-      "s_b3 = (P*math.cos(math.radians(40))/(4*t_B*d_b)) # bearing stress between anchor bolt and base plate\n",
-      "print \"Bearing stress between anchor bolts & base plate\", round(s_b3,1), \"ksi\"\n",
-      "\n",
-      "# Part (e)\n",
-      "t_bolt = (4*math.cos(math.radians(40))*P)/(4*math.pi*(d_b**2))  # shear stress in anchor bolt\n",
-      "print \"Shear stress in anchor bolts is\", round(t_bolt,1), \"ksi\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Bearing stress between strut and pin 21.3 ksi\n",
-        "Shear stress in pin is  13.6 ksi\n",
-        "Bearing stress between pin and gussets is 12.8 ksi\n",
-        "Bearing stress between anchor bolts & base plate 12.3 ksi\n",
-        "Shear stress in anchor bolts is 11.7 ksi\n"
-       ]
-      }
-     ],
-     "prompt_number": 39
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.7, page no. 42"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "determine stress at various parts\n",
-      "\"\"\"\n",
-      "\n",
-      "import math\n",
-      "\n",
-      "#initialisation\n",
-      "b1 = 1.5                            # width of recmath.tangular crosssection in inch\n",
-      "t = 0.5                             # thickness of recmath.tangular crosssection in inch\n",
-      "b2 = 3.0                            # width  of enlarged recmath.tangular crosssection in inch\n",
-      "d = 1.0                             # diameter in inch\n",
-      "\n",
-      "#calculation\n",
-      "\n",
-      "# Part (a)\n",
-      "s_1 = 16000 # maximum allowable tensile stress in Psi\n",
-      "P_1 = s_1*t*b1 \n",
-      "print \"The allowable load  P1 is\", P_1, \"lb\"\n",
-      "\n",
-      "# Part (b)\n",
-      "s_2 = 11000 # maximum allowable tensile stress in Psi\n",
-      "P_2 = s_2*t*(b2-d) \n",
-      "print \"allowable load P2 at this section is\", P_2, \"lb\"\n",
-      "\n",
-      "#Part (c)\n",
-      "s_3 = 26000 # maximum allowable tensile stress in Psi\n",
-      "P_3 = s_3*t*d \n",
-      "print \"The allowable load based upon bearing between the hanger and the bolt is\", P_3, \"lb\"\n",
-      "\n",
-      "# Part (d)\n",
-      "s_4 = 6500 # maximum allowable tensile stress in Psi\n",
-      "P_4 = (math.pi/4)*(d**2)*2*s_4 \n",
-      "print \"the allowable load  P4 based upon shear in the bolt is\", round(P_4), \"lb\"\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The allowable load  P1 is 12000.0 lb\n",
-        "allowable load P2 at this section is 11000.0 lb\n",
-        "The allowable load based upon bearing between the hanger and the bolt is 13000.0 lb\n",
-        "the allowable load  P4 based upon shear in the bolt is 10210.0 lb\n"
-       ]
-      }
-     ],
-     "prompt_number": 42
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.8, page no. 46"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculating the cross sectional area \n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "R_ah = (2700*0.8 + 2700*2.6)/2                  # Horizontal component at A in N\n",
-      "R_ch = R_ah                                     # Horizontal component at C in N\n",
-      "R_cv = (2700*2.2 + 2700*0.4)/3                  # vertical component at C in N\n",
-      "R_av = 2700 + 2700 - R_cv                       # vertical component at A in N\n",
-      "R_a = math.sqrt((R_ah**2)+(R_av**2))\n",
-      "R_c = math.sqrt((R_ch**2)+(R_cv**2))\n",
-      "Fab = R_a                                       # Tensile force in bar AB\n",
-      "Vc = R_c                                        # Shear force acting on the pin at C\n",
-      "s_allow = 125000000                             # allowable stress in tension \n",
-      "t_allow = 45000000                              # allowable stress in shear\n",
-      "\n",
-      "#calculation\n",
-      "Aab = Fab / s_allow                             # required area of bar \n",
-      "Apin = Vc / (2*t_allow)                         # required area of pin\n",
-      "\n",
-      "\n",
-      "print \"Required area of bar is %f\" %Apin, \"m^2\"\n",
-      "d = math.sqrt((4*Apin)/math.pi)                 # diameter in meter\n",
-      "print \"Required diameter of pin is %f\" %d, \"m\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Required area of bar is 0.000057 m^2\n",
-        "Required diameter of pin is 0.008537 m\n"
-       ]
-      }
-     ],
-     "prompt_number": 9
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [],
-     "language": "python",
-     "metadata": {},
-     "outputs": []
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Testing_the_interface/chapter11.ipynb b/Testing_the_interface/chapter11.ipynb
deleted file mode 100755
index b7650778..00000000
--- a/Testing_the_interface/chapter11.ipynb
+++ /dev/null
@@ -1,516 +0,0 @@
-{
- "metadata": {
-  "name": ""
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 11: Columns"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11.1, page no. 763"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "allowable load Pallow using a factor of safety & with respect to Euler buckling of the column\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "E = 29000                   # Modulus of elasticity in ksi\n",
-      "spl = 42                    # Proportional limit in ksi\n",
-      "L = 25                      # Total length of coloum in ft\n",
-      "n = 2.5                     # factor of safety\n",
-      "I1 = 98                     # Moment of inertia on horizontal axis\n",
-      "I2 = 21.7                   # Moment of inertia on vertical axis\n",
-      "A = 8.25                    # Area of the cross section\n",
-      "\n",
-      "#calculation\n",
-      "Pcr2 = (4*math.pi**2*E*I2)/((L*12)**2)          # Criticle load if column buckles in the plane of paper\n",
-      "Pcr1 = (math.pi**2*E*I1)/((L*12)**2)            # Criticle load if column buckles in the plane of paper\n",
-      "Pcr = min(Pcr1,Pcr2)                            # Minimum pressure would govern the design\n",
-      "scr = Pcr/A                                     # Criticle stress\n",
-      "Pa = Pcr/n                                      # Allowable load in k\n",
-      "print \"The allowable load is \", round(Pa), \"k\"\n",
-      " "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The allowable load is  110.0 k\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11.2, page no. 774"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculate minimum required thickness t of the columns\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "L = 3.25                        # Length of alluminium pipe in m\n",
-      "d = 0.1                         # Outer diameter of alluminium pipe\n",
-      "P = 100000                      # Allowable compressive load in N\n",
-      "n =3                            # Safety factor for eular buckling\n",
-      "E = 72e09                       # Modulus of elasticity in Pa\n",
-      "l = 480e06                      # Proportional limit\n",
-      "\n",
-      "#calculation\n",
-      "Pcr = n*P                                   # Critice load\n",
-      "t = (0.1-(55.6e-06)**(1.0/4.0) )/2.0        # Required thickness\n",
-      "\n",
-      "tmin = t \n",
-      "print \"The minimum required thickness of the coloumn is\", round(tmin*1000,2), \"mm\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The minimum required thickness of the coloumn is 6.82 mm\n"
-       ]
-      }
-     ],
-     "prompt_number": 2
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11.3, page no. 780"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "evaluate the longest permissible length of the bar\n",
-      "\"\"\"\n",
-      "\n",
-      "from sympy import *\n",
-      "\n",
-      "#initialisation\n",
-      "P = 1500                    # Load in lb\n",
-      "e = 0.45                    # ecentricity in inch\n",
-      "h = 1.2                     # Height of cross section in inch\n",
-      "b = 0.6                     # Width of cross section in inch\n",
-      "E = 16e06                   # Modulus of elasticity \n",
-      "my_del = 0.12               # Allowable deflection in inch\n",
-      "\n",
-      "#calculation\n",
-      "L = mpmath.asec(1.2667)/0.06588        # Maximum allowable length possible\n",
-      "\n",
-      "#Result\n",
-      "print \"The longest permissible length of the bar is\", round(L), \"inch\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The longest permissible length of the bar is 10.0 inch\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11.4, page no. 785"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "maximum compressive stress in the column & the factor of safety\n",
-      "\"\"\"\n",
-      "\n",
-      "from sympy import *\n",
-      "import math\n",
-      "\n",
-      "#initialisation\n",
-      "L = 25                      # Length of coloum in ft\n",
-      "P1 = 320                    # Load in K\n",
-      "P2 = 40                     # Load in K\n",
-      "E = 30000                   # Modulus of elasticity of steel in Ksi\n",
-      "P = 360                     # Euivalent load\n",
-      "e = 1.5                     # Ecentricity of compressive load\n",
-      "A = 24.1                    # Area of the Cross section\n",
-      "r = 6.05                    # in inch\n",
-      "c = 7.155                   # in inch\n",
-      "sy = 42                     # Yeild stress of steel in Ksi\n",
-      "\n",
-      "#calculation\n",
-      "\n",
-      "smax = (P/A)*(1+(((e*c)/r**2)*mpmath.sec((L/(2*r))*math.sqrt(P/(E*A)))))           # Maximum compressive stress\n",
-      "print \"The Maximum compressive stress in the column \", round(smax,2), \"ksi\"\n",
-      "# Bisection method method to solve for yeilding\n",
-      "def stress(a,b,f):\n",
-      "    N = 100\n",
-      "    eps = 1e-5\n",
-      "    if((f(a)*f(b))>0):\n",
-      "        print 'no root possible f(a)*f(b)>0'\n",
-      "        sys.exit()\n",
-      "    if(abs(f(a))<eps):\n",
-      "        print 'solution at a'\n",
-      "        sys.exit()\n",
-      "    if(abs(f(b))<eps):\n",
-      "        print 'solution at b'\n",
-      "    while(N>0):\n",
-      "        c = (a+b)/2.0\n",
-      "        if(abs(f(c))<eps):\n",
-      "            x = c \n",
-      "            return x\n",
-      "        if((f(a)*f(c))<0 ):\n",
-      "            b = c \n",
-      "        else:\n",
-      "          a = c \n",
-      "        N = N-1\n",
-      "    print 'no convergence'\n",
-      "    sys.exit()\n",
-      "\n",
-      "def p(x): \n",
-      "\t return  x + (0.2939*x*sec(0.02916*sqrt(x))) - 1012 \n",
-      "x = stress(710,750,p)\n",
-      "Py = x                  # Yeilding load in K\n",
-      "n = Py/P                # Factor of safety against yeilding\n",
-      "print \"The factor of safety against yeilding is\", round(n)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The Maximum compressive stress in the column  19.32 ksi\n",
-        "The factor of safety against yeilding is 2.0\n"
-       ]
-      }
-     ],
-     "prompt_number": 7
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11.5, page no. 804"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "the allowable axial load & max. permissible length\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "import numpy\n",
-      "\n",
-      "#initialisation\n",
-      "E = 29000                       # Modulus of elasticity in ksi\n",
-      "sy = 36                         # Yeilding stress in ksi\n",
-      "L = 20                          # Length of coloumn in ft\n",
-      "r = 2.57                        # radius of gyration of coloumn\n",
-      "K = 1                           # Effetive Length factor\n",
-      "\n",
-      "#calculation\n",
-      "s = math.sqrt((2*math.pi**2*E)/sy)          # Criticle slenderness ratio (K*L)/r\n",
-      "s_ = (L*12)/r                               # Slenderness ratio\n",
-      "\n",
-      "# Part(a)\n",
-      "n1 = (5.0/3.0)+((3.0/8.0)*(s_/s))-((1.0/8.0)*((s_**3)/(s**3)))  # Factor of safety \n",
-      "sallow = (sy/n1)*(1-((1.0/2.0)*((s_**2)/(s**2))))               # Allowable axial load\n",
-      "A = 17.6                                                        # Cross sectional area from table E1\n",
-      "Pallow = sallow*A                                               # Allowable axial load\n",
-      "print \"Allowable axial load is\", round(Pallow,2), \"k\"\n",
-      "\n",
-      "# Part (b)\n",
-      "Pe = 200                        # Permissible load in K\n",
-      "L_ = 25                         # Assumed length in ft\n",
-      "s__ = (L_*12)/r                 # Slenderness ratio\n",
-      "n1_ = (5.0/3.0)+((3.0/8.0)*(s__/s))-((1.0/8.0)*((s__**3)/(s**3)))   # Factor of safety \n",
-      "sallow_ = (sy/n1_)*(1-((1.0/2.0)*((s__**2)/(s**2))))                # Allowable axial load\n",
-      "A = 17.6                                                            # Area of the cross section in**2\n",
-      "Pallow = sallow_*A                                                  # Allowable load\n",
-      "L1 = [24, 24.4, 25]\n",
-      "P1 = [201, 194, 190]\n",
-      "L_max = numpy.interp(200.0, P1, L1)\n",
-      "print \"The maximum permissible length is\", L_max, \"ft\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Allowable axial load is 242.84 k\n",
-        "The maximum permissible length is 25.0 ft\n"
-       ]
-      }
-     ],
-     "prompt_number": 8
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11.6, page no. 806"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math \n",
-      "import numpy\n",
-      "\n",
-      "#initialisation\n",
-      "L = 3.6                         # Length of steel pipe coloumn\n",
-      "d = 0.16                        # Outer diameter in m\n",
-      "P = 240e03                      # Load in N\n",
-      "E = 200e09                      # Modulus of elasticity in Pa\n",
-      "sy = 259e06                     # yeilding stress in Pa\n",
-      "K = 2.0\n",
-      "Le = K*L                        # As it in fixed-free condition\n",
-      "\n",
-      "#calculation\n",
-      "sc = math.sqrt((2*math.pi**2*E)/sy) # Critical slenderness ratio\n",
-      "\n",
-      "# First trial\n",
-      "t = 0.007                               # Assumed thick ness in m\n",
-      "I = (math.pi/64)*(d**4-(d-2*t)**4)      # Moment of inertia\n",
-      "A = (math.pi/4)*(d**2-(d-2*t)**2)       # Area of cross section\n",
-      "r = math.sqrt(I/A)                      # Radius of gyration\n",
-      "sc_ = round((K*L)/r)                           # Slender ness ratio\n",
-      "n2 = 1.92                               # From equation 11.80\n",
-      "sa = (sy/(2*n2))*(sc**2/sc_**2)         # Allowable stress\n",
-      "Pa = round((sa*A)/1000)                 # Allowable axial load in N\n",
-      "\n",
-      "# Interpolation\n",
-      "t = [7, 8, 9]\n",
-      "Pa = [196, 220, 243]\n",
-      "t_min = numpy.interp(240.0, Pa, t)\n",
-      "print \"The minimum required thickness of the steel pipe is\", round(t_min,1), \"mm\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "196.0\n",
-        "The minimum required thickness of the steel pipe is 8.9 mm\n"
-       ]
-      }
-     ],
-     "prompt_number": 17
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11.7, page no. 808"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "max. require outer diameter\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "\n",
-      "L = 16                          # Effective length in inch\n",
-      "P = 5                           # axial load in K\n",
-      "\n",
-      "#calculation\n",
-      "# Bisection method for solvong the quaderatic\n",
-      "def stress(a,b,f):\n",
-      "    N = 100\n",
-      "    eps = 1e-5\n",
-      "    if((f(a)*f(b))>0):\n",
-      "        print 'no root possible f(a)*f(b)>0'\n",
-      "        sys.exit()\n",
-      "    if(abs(f(a))<eps):\n",
-      "        print 'solution at a'\n",
-      "        sys.exit()\n",
-      "    if(abs(f(b))<eps):\n",
-      "        print 'solution at b'\n",
-      "    while(N>0):\n",
-      "        c = (a+b)/2.0\n",
-      "        if(abs(f(c))<eps):\n",
-      "            x = c \n",
-      "            return x\n",
-      "        if((f(a)*f(c))<0 ):\n",
-      "            b = c \n",
-      "        else:\n",
-      "          a = c \n",
-      "        N = N-1\n",
-      "    print 'no convergence'\n",
-      "    sys.exit()\n",
-      "def p(x): \n",
-      "\t return  30.7*x**2 - 11.49*x -17.69 \n",
-      "x = stress(0.9,1.1,p)\n",
-      "d = x                               # Diameter in inch\n",
-      "sl = 49.97/d                        # Slenderness ration L/r\n",
-      "dmin = d                            # Minimum diameter\n",
-      "print \"The minimum required outer diameter of the tube is\", round(dmin,2), \"inch\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The minimum required outer diameter of the tube is 0.97 inch\n"
-       ]
-      }
-     ],
-     "prompt_number": 11
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11.8, page no. 810"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculate various quantities\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "Fc = 11e06                          # Compressive demath.sing stress in Pa\n",
-      "E = 13e09                           # Modulus of elasticity in Pa\n",
-      "\n",
-      "#calculation\n",
-      "# Part (a)\n",
-      "Kce = 0.3  \n",
-      "c = 0.8 \n",
-      "A = 0.12*0.16                           # Area of cross section\n",
-      "Sl = 1.8/0.12                           # Slenderness ratio\n",
-      "fi = (Kce*E)/(Fc*Sl**2)                 # ratio of stresses\n",
-      "Cp = ((1+fi)/(2*c)) - math.sqrt(((1+fi)/(2*c))**2-(fi/c)) # Coloumn stability factor \n",
-      "Pa = Fc*Cp*A\n",
-      "print \"The allowable axial load is\", Pa, \"N\"\n",
-      "\n",
-      "# Part (b)\n",
-      "P = 100000                              # Allowable Axial load\n",
-      "Cp_ = P/(Fc*A)                          # Coloumn stability factor\n",
-      "\n",
-      "# Bisection method method to solve for fi\n",
-      "def stress(a,b,f):\n",
-      "    N = 100\n",
-      "    eps = 1e-5\n",
-      "    if((f(a)*f(b))>0):\n",
-      "        print 'no root possible f(a)*f(b)>0'\n",
-      "        sys.exit()\n",
-      "    if(abs(f(a))<eps):\n",
-      "        print 'solution at a'\n",
-      "        sys.exit()\n",
-      "    if(abs(f(b))<eps):\n",
-      "        print 'solution at b'\n",
-      "    while(N>0):\n",
-      "        c = (a+b)/2.0\n",
-      "        if(abs(f(c))<eps):\n",
-      "            x = c \n",
-      "            return x\n",
-      "        if((f(a)*f(c))<0 ):\n",
-      "            b = c \n",
-      "        else:\n",
-      "          a = c \n",
-      "        N = N-1\n",
-      "    print 'no convergence'\n",
-      "    sys.exit()\n",
-      "def p(x): \n",
-      "    return  ((1+x)/(2.0*c)) - math.sqrt(((1+x)/(2.0*c))**2-(x/c)) - Cp_ \n",
-      "x = stress(0.1,1.0,p) \n",
-      "fi_ = x\n",
-      "d_ = 0.12                               # Diameter in m\n",
-      "L_max = d_*math.sqrt((Kce*E)/(fi_*Fc))  # Maximum length in m\n",
-      "print \"The minimum allowable length is\", round(L_max,2), \"m\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The allowable axial load is 173444.30361 N\n",
-        "The minimum allowable length is 3.02 m\n"
-       ]
-      }
-     ],
-     "prompt_number": 12
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Testing_the_interface/chapter11_1.ipynb b/Testing_the_interface/chapter11_1.ipynb
deleted file mode 100755
index b7650778..00000000
--- a/Testing_the_interface/chapter11_1.ipynb
+++ /dev/null
@@ -1,516 +0,0 @@
-{
- "metadata": {
-  "name": ""
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 11: Columns"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11.1, page no. 763"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "allowable load Pallow using a factor of safety & with respect to Euler buckling of the column\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "E = 29000                   # Modulus of elasticity in ksi\n",
-      "spl = 42                    # Proportional limit in ksi\n",
-      "L = 25                      # Total length of coloum in ft\n",
-      "n = 2.5                     # factor of safety\n",
-      "I1 = 98                     # Moment of inertia on horizontal axis\n",
-      "I2 = 21.7                   # Moment of inertia on vertical axis\n",
-      "A = 8.25                    # Area of the cross section\n",
-      "\n",
-      "#calculation\n",
-      "Pcr2 = (4*math.pi**2*E*I2)/((L*12)**2)          # Criticle load if column buckles in the plane of paper\n",
-      "Pcr1 = (math.pi**2*E*I1)/((L*12)**2)            # Criticle load if column buckles in the plane of paper\n",
-      "Pcr = min(Pcr1,Pcr2)                            # Minimum pressure would govern the design\n",
-      "scr = Pcr/A                                     # Criticle stress\n",
-      "Pa = Pcr/n                                      # Allowable load in k\n",
-      "print \"The allowable load is \", round(Pa), \"k\"\n",
-      " "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The allowable load is  110.0 k\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11.2, page no. 774"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculate minimum required thickness t of the columns\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "L = 3.25                        # Length of alluminium pipe in m\n",
-      "d = 0.1                         # Outer diameter of alluminium pipe\n",
-      "P = 100000                      # Allowable compressive load in N\n",
-      "n =3                            # Safety factor for eular buckling\n",
-      "E = 72e09                       # Modulus of elasticity in Pa\n",
-      "l = 480e06                      # Proportional limit\n",
-      "\n",
-      "#calculation\n",
-      "Pcr = n*P                                   # Critice load\n",
-      "t = (0.1-(55.6e-06)**(1.0/4.0) )/2.0        # Required thickness\n",
-      "\n",
-      "tmin = t \n",
-      "print \"The minimum required thickness of the coloumn is\", round(tmin*1000,2), \"mm\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The minimum required thickness of the coloumn is 6.82 mm\n"
-       ]
-      }
-     ],
-     "prompt_number": 2
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11.3, page no. 780"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "evaluate the longest permissible length of the bar\n",
-      "\"\"\"\n",
-      "\n",
-      "from sympy import *\n",
-      "\n",
-      "#initialisation\n",
-      "P = 1500                    # Load in lb\n",
-      "e = 0.45                    # ecentricity in inch\n",
-      "h = 1.2                     # Height of cross section in inch\n",
-      "b = 0.6                     # Width of cross section in inch\n",
-      "E = 16e06                   # Modulus of elasticity \n",
-      "my_del = 0.12               # Allowable deflection in inch\n",
-      "\n",
-      "#calculation\n",
-      "L = mpmath.asec(1.2667)/0.06588        # Maximum allowable length possible\n",
-      "\n",
-      "#Result\n",
-      "print \"The longest permissible length of the bar is\", round(L), \"inch\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The longest permissible length of the bar is 10.0 inch\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11.4, page no. 785"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "maximum compressive stress in the column & the factor of safety\n",
-      "\"\"\"\n",
-      "\n",
-      "from sympy import *\n",
-      "import math\n",
-      "\n",
-      "#initialisation\n",
-      "L = 25                      # Length of coloum in ft\n",
-      "P1 = 320                    # Load in K\n",
-      "P2 = 40                     # Load in K\n",
-      "E = 30000                   # Modulus of elasticity of steel in Ksi\n",
-      "P = 360                     # Euivalent load\n",
-      "e = 1.5                     # Ecentricity of compressive load\n",
-      "A = 24.1                    # Area of the Cross section\n",
-      "r = 6.05                    # in inch\n",
-      "c = 7.155                   # in inch\n",
-      "sy = 42                     # Yeild stress of steel in Ksi\n",
-      "\n",
-      "#calculation\n",
-      "\n",
-      "smax = (P/A)*(1+(((e*c)/r**2)*mpmath.sec((L/(2*r))*math.sqrt(P/(E*A)))))           # Maximum compressive stress\n",
-      "print \"The Maximum compressive stress in the column \", round(smax,2), \"ksi\"\n",
-      "# Bisection method method to solve for yeilding\n",
-      "def stress(a,b,f):\n",
-      "    N = 100\n",
-      "    eps = 1e-5\n",
-      "    if((f(a)*f(b))>0):\n",
-      "        print 'no root possible f(a)*f(b)>0'\n",
-      "        sys.exit()\n",
-      "    if(abs(f(a))<eps):\n",
-      "        print 'solution at a'\n",
-      "        sys.exit()\n",
-      "    if(abs(f(b))<eps):\n",
-      "        print 'solution at b'\n",
-      "    while(N>0):\n",
-      "        c = (a+b)/2.0\n",
-      "        if(abs(f(c))<eps):\n",
-      "            x = c \n",
-      "            return x\n",
-      "        if((f(a)*f(c))<0 ):\n",
-      "            b = c \n",
-      "        else:\n",
-      "          a = c \n",
-      "        N = N-1\n",
-      "    print 'no convergence'\n",
-      "    sys.exit()\n",
-      "\n",
-      "def p(x): \n",
-      "\t return  x + (0.2939*x*sec(0.02916*sqrt(x))) - 1012 \n",
-      "x = stress(710,750,p)\n",
-      "Py = x                  # Yeilding load in K\n",
-      "n = Py/P                # Factor of safety against yeilding\n",
-      "print \"The factor of safety against yeilding is\", round(n)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The Maximum compressive stress in the column  19.32 ksi\n",
-        "The factor of safety against yeilding is 2.0\n"
-       ]
-      }
-     ],
-     "prompt_number": 7
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11.5, page no. 804"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "the allowable axial load & max. permissible length\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "import numpy\n",
-      "\n",
-      "#initialisation\n",
-      "E = 29000                       # Modulus of elasticity in ksi\n",
-      "sy = 36                         # Yeilding stress in ksi\n",
-      "L = 20                          # Length of coloumn in ft\n",
-      "r = 2.57                        # radius of gyration of coloumn\n",
-      "K = 1                           # Effetive Length factor\n",
-      "\n",
-      "#calculation\n",
-      "s = math.sqrt((2*math.pi**2*E)/sy)          # Criticle slenderness ratio (K*L)/r\n",
-      "s_ = (L*12)/r                               # Slenderness ratio\n",
-      "\n",
-      "# Part(a)\n",
-      "n1 = (5.0/3.0)+((3.0/8.0)*(s_/s))-((1.0/8.0)*((s_**3)/(s**3)))  # Factor of safety \n",
-      "sallow = (sy/n1)*(1-((1.0/2.0)*((s_**2)/(s**2))))               # Allowable axial load\n",
-      "A = 17.6                                                        # Cross sectional area from table E1\n",
-      "Pallow = sallow*A                                               # Allowable axial load\n",
-      "print \"Allowable axial load is\", round(Pallow,2), \"k\"\n",
-      "\n",
-      "# Part (b)\n",
-      "Pe = 200                        # Permissible load in K\n",
-      "L_ = 25                         # Assumed length in ft\n",
-      "s__ = (L_*12)/r                 # Slenderness ratio\n",
-      "n1_ = (5.0/3.0)+((3.0/8.0)*(s__/s))-((1.0/8.0)*((s__**3)/(s**3)))   # Factor of safety \n",
-      "sallow_ = (sy/n1_)*(1-((1.0/2.0)*((s__**2)/(s**2))))                # Allowable axial load\n",
-      "A = 17.6                                                            # Area of the cross section in**2\n",
-      "Pallow = sallow_*A                                                  # Allowable load\n",
-      "L1 = [24, 24.4, 25]\n",
-      "P1 = [201, 194, 190]\n",
-      "L_max = numpy.interp(200.0, P1, L1)\n",
-      "print \"The maximum permissible length is\", L_max, \"ft\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Allowable axial load is 242.84 k\n",
-        "The maximum permissible length is 25.0 ft\n"
-       ]
-      }
-     ],
-     "prompt_number": 8
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11.6, page no. 806"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math \n",
-      "import numpy\n",
-      "\n",
-      "#initialisation\n",
-      "L = 3.6                         # Length of steel pipe coloumn\n",
-      "d = 0.16                        # Outer diameter in m\n",
-      "P = 240e03                      # Load in N\n",
-      "E = 200e09                      # Modulus of elasticity in Pa\n",
-      "sy = 259e06                     # yeilding stress in Pa\n",
-      "K = 2.0\n",
-      "Le = K*L                        # As it in fixed-free condition\n",
-      "\n",
-      "#calculation\n",
-      "sc = math.sqrt((2*math.pi**2*E)/sy) # Critical slenderness ratio\n",
-      "\n",
-      "# First trial\n",
-      "t = 0.007                               # Assumed thick ness in m\n",
-      "I = (math.pi/64)*(d**4-(d-2*t)**4)      # Moment of inertia\n",
-      "A = (math.pi/4)*(d**2-(d-2*t)**2)       # Area of cross section\n",
-      "r = math.sqrt(I/A)                      # Radius of gyration\n",
-      "sc_ = round((K*L)/r)                           # Slender ness ratio\n",
-      "n2 = 1.92                               # From equation 11.80\n",
-      "sa = (sy/(2*n2))*(sc**2/sc_**2)         # Allowable stress\n",
-      "Pa = round((sa*A)/1000)                 # Allowable axial load in N\n",
-      "\n",
-      "# Interpolation\n",
-      "t = [7, 8, 9]\n",
-      "Pa = [196, 220, 243]\n",
-      "t_min = numpy.interp(240.0, Pa, t)\n",
-      "print \"The minimum required thickness of the steel pipe is\", round(t_min,1), \"mm\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "196.0\n",
-        "The minimum required thickness of the steel pipe is 8.9 mm\n"
-       ]
-      }
-     ],
-     "prompt_number": 17
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11.7, page no. 808"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "max. require outer diameter\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "\n",
-      "L = 16                          # Effective length in inch\n",
-      "P = 5                           # axial load in K\n",
-      "\n",
-      "#calculation\n",
-      "# Bisection method for solvong the quaderatic\n",
-      "def stress(a,b,f):\n",
-      "    N = 100\n",
-      "    eps = 1e-5\n",
-      "    if((f(a)*f(b))>0):\n",
-      "        print 'no root possible f(a)*f(b)>0'\n",
-      "        sys.exit()\n",
-      "    if(abs(f(a))<eps):\n",
-      "        print 'solution at a'\n",
-      "        sys.exit()\n",
-      "    if(abs(f(b))<eps):\n",
-      "        print 'solution at b'\n",
-      "    while(N>0):\n",
-      "        c = (a+b)/2.0\n",
-      "        if(abs(f(c))<eps):\n",
-      "            x = c \n",
-      "            return x\n",
-      "        if((f(a)*f(c))<0 ):\n",
-      "            b = c \n",
-      "        else:\n",
-      "          a = c \n",
-      "        N = N-1\n",
-      "    print 'no convergence'\n",
-      "    sys.exit()\n",
-      "def p(x): \n",
-      "\t return  30.7*x**2 - 11.49*x -17.69 \n",
-      "x = stress(0.9,1.1,p)\n",
-      "d = x                               # Diameter in inch\n",
-      "sl = 49.97/d                        # Slenderness ration L/r\n",
-      "dmin = d                            # Minimum diameter\n",
-      "print \"The minimum required outer diameter of the tube is\", round(dmin,2), \"inch\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The minimum required outer diameter of the tube is 0.97 inch\n"
-       ]
-      }
-     ],
-     "prompt_number": 11
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11.8, page no. 810"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculate various quantities\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "Fc = 11e06                          # Compressive demath.sing stress in Pa\n",
-      "E = 13e09                           # Modulus of elasticity in Pa\n",
-      "\n",
-      "#calculation\n",
-      "# Part (a)\n",
-      "Kce = 0.3  \n",
-      "c = 0.8 \n",
-      "A = 0.12*0.16                           # Area of cross section\n",
-      "Sl = 1.8/0.12                           # Slenderness ratio\n",
-      "fi = (Kce*E)/(Fc*Sl**2)                 # ratio of stresses\n",
-      "Cp = ((1+fi)/(2*c)) - math.sqrt(((1+fi)/(2*c))**2-(fi/c)) # Coloumn stability factor \n",
-      "Pa = Fc*Cp*A\n",
-      "print \"The allowable axial load is\", Pa, \"N\"\n",
-      "\n",
-      "# Part (b)\n",
-      "P = 100000                              # Allowable Axial load\n",
-      "Cp_ = P/(Fc*A)                          # Coloumn stability factor\n",
-      "\n",
-      "# Bisection method method to solve for fi\n",
-      "def stress(a,b,f):\n",
-      "    N = 100\n",
-      "    eps = 1e-5\n",
-      "    if((f(a)*f(b))>0):\n",
-      "        print 'no root possible f(a)*f(b)>0'\n",
-      "        sys.exit()\n",
-      "    if(abs(f(a))<eps):\n",
-      "        print 'solution at a'\n",
-      "        sys.exit()\n",
-      "    if(abs(f(b))<eps):\n",
-      "        print 'solution at b'\n",
-      "    while(N>0):\n",
-      "        c = (a+b)/2.0\n",
-      "        if(abs(f(c))<eps):\n",
-      "            x = c \n",
-      "            return x\n",
-      "        if((f(a)*f(c))<0 ):\n",
-      "            b = c \n",
-      "        else:\n",
-      "          a = c \n",
-      "        N = N-1\n",
-      "    print 'no convergence'\n",
-      "    sys.exit()\n",
-      "def p(x): \n",
-      "    return  ((1+x)/(2.0*c)) - math.sqrt(((1+x)/(2.0*c))**2-(x/c)) - Cp_ \n",
-      "x = stress(0.1,1.0,p) \n",
-      "fi_ = x\n",
-      "d_ = 0.12                               # Diameter in m\n",
-      "L_max = d_*math.sqrt((Kce*E)/(fi_*Fc))  # Maximum length in m\n",
-      "print \"The minimum allowable length is\", round(L_max,2), \"m\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The allowable axial load is 173444.30361 N\n",
-        "The minimum allowable length is 3.02 m\n"
-       ]
-      }
-     ],
-     "prompt_number": 12
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Testing_the_interface/chapter11_2.ipynb b/Testing_the_interface/chapter11_2.ipynb
deleted file mode 100755
index b7650778..00000000
--- a/Testing_the_interface/chapter11_2.ipynb
+++ /dev/null
@@ -1,516 +0,0 @@
-{
- "metadata": {
-  "name": ""
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 11: Columns"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11.1, page no. 763"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "allowable load Pallow using a factor of safety & with respect to Euler buckling of the column\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "E = 29000                   # Modulus of elasticity in ksi\n",
-      "spl = 42                    # Proportional limit in ksi\n",
-      "L = 25                      # Total length of coloum in ft\n",
-      "n = 2.5                     # factor of safety\n",
-      "I1 = 98                     # Moment of inertia on horizontal axis\n",
-      "I2 = 21.7                   # Moment of inertia on vertical axis\n",
-      "A = 8.25                    # Area of the cross section\n",
-      "\n",
-      "#calculation\n",
-      "Pcr2 = (4*math.pi**2*E*I2)/((L*12)**2)          # Criticle load if column buckles in the plane of paper\n",
-      "Pcr1 = (math.pi**2*E*I1)/((L*12)**2)            # Criticle load if column buckles in the plane of paper\n",
-      "Pcr = min(Pcr1,Pcr2)                            # Minimum pressure would govern the design\n",
-      "scr = Pcr/A                                     # Criticle stress\n",
-      "Pa = Pcr/n                                      # Allowable load in k\n",
-      "print \"The allowable load is \", round(Pa), \"k\"\n",
-      " "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The allowable load is  110.0 k\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11.2, page no. 774"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculate minimum required thickness t of the columns\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "L = 3.25                        # Length of alluminium pipe in m\n",
-      "d = 0.1                         # Outer diameter of alluminium pipe\n",
-      "P = 100000                      # Allowable compressive load in N\n",
-      "n =3                            # Safety factor for eular buckling\n",
-      "E = 72e09                       # Modulus of elasticity in Pa\n",
-      "l = 480e06                      # Proportional limit\n",
-      "\n",
-      "#calculation\n",
-      "Pcr = n*P                                   # Critice load\n",
-      "t = (0.1-(55.6e-06)**(1.0/4.0) )/2.0        # Required thickness\n",
-      "\n",
-      "tmin = t \n",
-      "print \"The minimum required thickness of the coloumn is\", round(tmin*1000,2), \"mm\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The minimum required thickness of the coloumn is 6.82 mm\n"
-       ]
-      }
-     ],
-     "prompt_number": 2
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11.3, page no. 780"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "evaluate the longest permissible length of the bar\n",
-      "\"\"\"\n",
-      "\n",
-      "from sympy import *\n",
-      "\n",
-      "#initialisation\n",
-      "P = 1500                    # Load in lb\n",
-      "e = 0.45                    # ecentricity in inch\n",
-      "h = 1.2                     # Height of cross section in inch\n",
-      "b = 0.6                     # Width of cross section in inch\n",
-      "E = 16e06                   # Modulus of elasticity \n",
-      "my_del = 0.12               # Allowable deflection in inch\n",
-      "\n",
-      "#calculation\n",
-      "L = mpmath.asec(1.2667)/0.06588        # Maximum allowable length possible\n",
-      "\n",
-      "#Result\n",
-      "print \"The longest permissible length of the bar is\", round(L), \"inch\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The longest permissible length of the bar is 10.0 inch\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11.4, page no. 785"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "maximum compressive stress in the column & the factor of safety\n",
-      "\"\"\"\n",
-      "\n",
-      "from sympy import *\n",
-      "import math\n",
-      "\n",
-      "#initialisation\n",
-      "L = 25                      # Length of coloum in ft\n",
-      "P1 = 320                    # Load in K\n",
-      "P2 = 40                     # Load in K\n",
-      "E = 30000                   # Modulus of elasticity of steel in Ksi\n",
-      "P = 360                     # Euivalent load\n",
-      "e = 1.5                     # Ecentricity of compressive load\n",
-      "A = 24.1                    # Area of the Cross section\n",
-      "r = 6.05                    # in inch\n",
-      "c = 7.155                   # in inch\n",
-      "sy = 42                     # Yeild stress of steel in Ksi\n",
-      "\n",
-      "#calculation\n",
-      "\n",
-      "smax = (P/A)*(1+(((e*c)/r**2)*mpmath.sec((L/(2*r))*math.sqrt(P/(E*A)))))           # Maximum compressive stress\n",
-      "print \"The Maximum compressive stress in the column \", round(smax,2), \"ksi\"\n",
-      "# Bisection method method to solve for yeilding\n",
-      "def stress(a,b,f):\n",
-      "    N = 100\n",
-      "    eps = 1e-5\n",
-      "    if((f(a)*f(b))>0):\n",
-      "        print 'no root possible f(a)*f(b)>0'\n",
-      "        sys.exit()\n",
-      "    if(abs(f(a))<eps):\n",
-      "        print 'solution at a'\n",
-      "        sys.exit()\n",
-      "    if(abs(f(b))<eps):\n",
-      "        print 'solution at b'\n",
-      "    while(N>0):\n",
-      "        c = (a+b)/2.0\n",
-      "        if(abs(f(c))<eps):\n",
-      "            x = c \n",
-      "            return x\n",
-      "        if((f(a)*f(c))<0 ):\n",
-      "            b = c \n",
-      "        else:\n",
-      "          a = c \n",
-      "        N = N-1\n",
-      "    print 'no convergence'\n",
-      "    sys.exit()\n",
-      "\n",
-      "def p(x): \n",
-      "\t return  x + (0.2939*x*sec(0.02916*sqrt(x))) - 1012 \n",
-      "x = stress(710,750,p)\n",
-      "Py = x                  # Yeilding load in K\n",
-      "n = Py/P                # Factor of safety against yeilding\n",
-      "print \"The factor of safety against yeilding is\", round(n)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The Maximum compressive stress in the column  19.32 ksi\n",
-        "The factor of safety against yeilding is 2.0\n"
-       ]
-      }
-     ],
-     "prompt_number": 7
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11.5, page no. 804"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "the allowable axial load & max. permissible length\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "import numpy\n",
-      "\n",
-      "#initialisation\n",
-      "E = 29000                       # Modulus of elasticity in ksi\n",
-      "sy = 36                         # Yeilding stress in ksi\n",
-      "L = 20                          # Length of coloumn in ft\n",
-      "r = 2.57                        # radius of gyration of coloumn\n",
-      "K = 1                           # Effetive Length factor\n",
-      "\n",
-      "#calculation\n",
-      "s = math.sqrt((2*math.pi**2*E)/sy)          # Criticle slenderness ratio (K*L)/r\n",
-      "s_ = (L*12)/r                               # Slenderness ratio\n",
-      "\n",
-      "# Part(a)\n",
-      "n1 = (5.0/3.0)+((3.0/8.0)*(s_/s))-((1.0/8.0)*((s_**3)/(s**3)))  # Factor of safety \n",
-      "sallow = (sy/n1)*(1-((1.0/2.0)*((s_**2)/(s**2))))               # Allowable axial load\n",
-      "A = 17.6                                                        # Cross sectional area from table E1\n",
-      "Pallow = sallow*A                                               # Allowable axial load\n",
-      "print \"Allowable axial load is\", round(Pallow,2), \"k\"\n",
-      "\n",
-      "# Part (b)\n",
-      "Pe = 200                        # Permissible load in K\n",
-      "L_ = 25                         # Assumed length in ft\n",
-      "s__ = (L_*12)/r                 # Slenderness ratio\n",
-      "n1_ = (5.0/3.0)+((3.0/8.0)*(s__/s))-((1.0/8.0)*((s__**3)/(s**3)))   # Factor of safety \n",
-      "sallow_ = (sy/n1_)*(1-((1.0/2.0)*((s__**2)/(s**2))))                # Allowable axial load\n",
-      "A = 17.6                                                            # Area of the cross section in**2\n",
-      "Pallow = sallow_*A                                                  # Allowable load\n",
-      "L1 = [24, 24.4, 25]\n",
-      "P1 = [201, 194, 190]\n",
-      "L_max = numpy.interp(200.0, P1, L1)\n",
-      "print \"The maximum permissible length is\", L_max, \"ft\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Allowable axial load is 242.84 k\n",
-        "The maximum permissible length is 25.0 ft\n"
-       ]
-      }
-     ],
-     "prompt_number": 8
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11.6, page no. 806"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math \n",
-      "import numpy\n",
-      "\n",
-      "#initialisation\n",
-      "L = 3.6                         # Length of steel pipe coloumn\n",
-      "d = 0.16                        # Outer diameter in m\n",
-      "P = 240e03                      # Load in N\n",
-      "E = 200e09                      # Modulus of elasticity in Pa\n",
-      "sy = 259e06                     # yeilding stress in Pa\n",
-      "K = 2.0\n",
-      "Le = K*L                        # As it in fixed-free condition\n",
-      "\n",
-      "#calculation\n",
-      "sc = math.sqrt((2*math.pi**2*E)/sy) # Critical slenderness ratio\n",
-      "\n",
-      "# First trial\n",
-      "t = 0.007                               # Assumed thick ness in m\n",
-      "I = (math.pi/64)*(d**4-(d-2*t)**4)      # Moment of inertia\n",
-      "A = (math.pi/4)*(d**2-(d-2*t)**2)       # Area of cross section\n",
-      "r = math.sqrt(I/A)                      # Radius of gyration\n",
-      "sc_ = round((K*L)/r)                           # Slender ness ratio\n",
-      "n2 = 1.92                               # From equation 11.80\n",
-      "sa = (sy/(2*n2))*(sc**2/sc_**2)         # Allowable stress\n",
-      "Pa = round((sa*A)/1000)                 # Allowable axial load in N\n",
-      "\n",
-      "# Interpolation\n",
-      "t = [7, 8, 9]\n",
-      "Pa = [196, 220, 243]\n",
-      "t_min = numpy.interp(240.0, Pa, t)\n",
-      "print \"The minimum required thickness of the steel pipe is\", round(t_min,1), \"mm\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "196.0\n",
-        "The minimum required thickness of the steel pipe is 8.9 mm\n"
-       ]
-      }
-     ],
-     "prompt_number": 17
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11.7, page no. 808"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "max. require outer diameter\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "\n",
-      "L = 16                          # Effective length in inch\n",
-      "P = 5                           # axial load in K\n",
-      "\n",
-      "#calculation\n",
-      "# Bisection method for solvong the quaderatic\n",
-      "def stress(a,b,f):\n",
-      "    N = 100\n",
-      "    eps = 1e-5\n",
-      "    if((f(a)*f(b))>0):\n",
-      "        print 'no root possible f(a)*f(b)>0'\n",
-      "        sys.exit()\n",
-      "    if(abs(f(a))<eps):\n",
-      "        print 'solution at a'\n",
-      "        sys.exit()\n",
-      "    if(abs(f(b))<eps):\n",
-      "        print 'solution at b'\n",
-      "    while(N>0):\n",
-      "        c = (a+b)/2.0\n",
-      "        if(abs(f(c))<eps):\n",
-      "            x = c \n",
-      "            return x\n",
-      "        if((f(a)*f(c))<0 ):\n",
-      "            b = c \n",
-      "        else:\n",
-      "          a = c \n",
-      "        N = N-1\n",
-      "    print 'no convergence'\n",
-      "    sys.exit()\n",
-      "def p(x): \n",
-      "\t return  30.7*x**2 - 11.49*x -17.69 \n",
-      "x = stress(0.9,1.1,p)\n",
-      "d = x                               # Diameter in inch\n",
-      "sl = 49.97/d                        # Slenderness ration L/r\n",
-      "dmin = d                            # Minimum diameter\n",
-      "print \"The minimum required outer diameter of the tube is\", round(dmin,2), \"inch\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The minimum required outer diameter of the tube is 0.97 inch\n"
-       ]
-      }
-     ],
-     "prompt_number": 11
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11.8, page no. 810"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculate various quantities\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "Fc = 11e06                          # Compressive demath.sing stress in Pa\n",
-      "E = 13e09                           # Modulus of elasticity in Pa\n",
-      "\n",
-      "#calculation\n",
-      "# Part (a)\n",
-      "Kce = 0.3  \n",
-      "c = 0.8 \n",
-      "A = 0.12*0.16                           # Area of cross section\n",
-      "Sl = 1.8/0.12                           # Slenderness ratio\n",
-      "fi = (Kce*E)/(Fc*Sl**2)                 # ratio of stresses\n",
-      "Cp = ((1+fi)/(2*c)) - math.sqrt(((1+fi)/(2*c))**2-(fi/c)) # Coloumn stability factor \n",
-      "Pa = Fc*Cp*A\n",
-      "print \"The allowable axial load is\", Pa, \"N\"\n",
-      "\n",
-      "# Part (b)\n",
-      "P = 100000                              # Allowable Axial load\n",
-      "Cp_ = P/(Fc*A)                          # Coloumn stability factor\n",
-      "\n",
-      "# Bisection method method to solve for fi\n",
-      "def stress(a,b,f):\n",
-      "    N = 100\n",
-      "    eps = 1e-5\n",
-      "    if((f(a)*f(b))>0):\n",
-      "        print 'no root possible f(a)*f(b)>0'\n",
-      "        sys.exit()\n",
-      "    if(abs(f(a))<eps):\n",
-      "        print 'solution at a'\n",
-      "        sys.exit()\n",
-      "    if(abs(f(b))<eps):\n",
-      "        print 'solution at b'\n",
-      "    while(N>0):\n",
-      "        c = (a+b)/2.0\n",
-      "        if(abs(f(c))<eps):\n",
-      "            x = c \n",
-      "            return x\n",
-      "        if((f(a)*f(c))<0 ):\n",
-      "            b = c \n",
-      "        else:\n",
-      "          a = c \n",
-      "        N = N-1\n",
-      "    print 'no convergence'\n",
-      "    sys.exit()\n",
-      "def p(x): \n",
-      "    return  ((1+x)/(2.0*c)) - math.sqrt(((1+x)/(2.0*c))**2-(x/c)) - Cp_ \n",
-      "x = stress(0.1,1.0,p) \n",
-      "fi_ = x\n",
-      "d_ = 0.12                               # Diameter in m\n",
-      "L_max = d_*math.sqrt((Kce*E)/(fi_*Fc))  # Maximum length in m\n",
-      "print \"The minimum allowable length is\", round(L_max,2), \"m\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The allowable axial load is 173444.30361 N\n",
-        "The minimum allowable length is 3.02 m\n"
-       ]
-      }
-     ],
-     "prompt_number": 12
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Testing_the_interface/chapter11_3.ipynb b/Testing_the_interface/chapter11_3.ipynb
deleted file mode 100755
index b7650778..00000000
--- a/Testing_the_interface/chapter11_3.ipynb
+++ /dev/null
@@ -1,516 +0,0 @@
-{
- "metadata": {
-  "name": ""
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 11: Columns"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11.1, page no. 763"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "allowable load Pallow using a factor of safety & with respect to Euler buckling of the column\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "E = 29000                   # Modulus of elasticity in ksi\n",
-      "spl = 42                    # Proportional limit in ksi\n",
-      "L = 25                      # Total length of coloum in ft\n",
-      "n = 2.5                     # factor of safety\n",
-      "I1 = 98                     # Moment of inertia on horizontal axis\n",
-      "I2 = 21.7                   # Moment of inertia on vertical axis\n",
-      "A = 8.25                    # Area of the cross section\n",
-      "\n",
-      "#calculation\n",
-      "Pcr2 = (4*math.pi**2*E*I2)/((L*12)**2)          # Criticle load if column buckles in the plane of paper\n",
-      "Pcr1 = (math.pi**2*E*I1)/((L*12)**2)            # Criticle load if column buckles in the plane of paper\n",
-      "Pcr = min(Pcr1,Pcr2)                            # Minimum pressure would govern the design\n",
-      "scr = Pcr/A                                     # Criticle stress\n",
-      "Pa = Pcr/n                                      # Allowable load in k\n",
-      "print \"The allowable load is \", round(Pa), \"k\"\n",
-      " "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The allowable load is  110.0 k\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11.2, page no. 774"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculate minimum required thickness t of the columns\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "L = 3.25                        # Length of alluminium pipe in m\n",
-      "d = 0.1                         # Outer diameter of alluminium pipe\n",
-      "P = 100000                      # Allowable compressive load in N\n",
-      "n =3                            # Safety factor for eular buckling\n",
-      "E = 72e09                       # Modulus of elasticity in Pa\n",
-      "l = 480e06                      # Proportional limit\n",
-      "\n",
-      "#calculation\n",
-      "Pcr = n*P                                   # Critice load\n",
-      "t = (0.1-(55.6e-06)**(1.0/4.0) )/2.0        # Required thickness\n",
-      "\n",
-      "tmin = t \n",
-      "print \"The minimum required thickness of the coloumn is\", round(tmin*1000,2), \"mm\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The minimum required thickness of the coloumn is 6.82 mm\n"
-       ]
-      }
-     ],
-     "prompt_number": 2
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11.3, page no. 780"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "evaluate the longest permissible length of the bar\n",
-      "\"\"\"\n",
-      "\n",
-      "from sympy import *\n",
-      "\n",
-      "#initialisation\n",
-      "P = 1500                    # Load in lb\n",
-      "e = 0.45                    # ecentricity in inch\n",
-      "h = 1.2                     # Height of cross section in inch\n",
-      "b = 0.6                     # Width of cross section in inch\n",
-      "E = 16e06                   # Modulus of elasticity \n",
-      "my_del = 0.12               # Allowable deflection in inch\n",
-      "\n",
-      "#calculation\n",
-      "L = mpmath.asec(1.2667)/0.06588        # Maximum allowable length possible\n",
-      "\n",
-      "#Result\n",
-      "print \"The longest permissible length of the bar is\", round(L), \"inch\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The longest permissible length of the bar is 10.0 inch\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11.4, page no. 785"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "maximum compressive stress in the column & the factor of safety\n",
-      "\"\"\"\n",
-      "\n",
-      "from sympy import *\n",
-      "import math\n",
-      "\n",
-      "#initialisation\n",
-      "L = 25                      # Length of coloum in ft\n",
-      "P1 = 320                    # Load in K\n",
-      "P2 = 40                     # Load in K\n",
-      "E = 30000                   # Modulus of elasticity of steel in Ksi\n",
-      "P = 360                     # Euivalent load\n",
-      "e = 1.5                     # Ecentricity of compressive load\n",
-      "A = 24.1                    # Area of the Cross section\n",
-      "r = 6.05                    # in inch\n",
-      "c = 7.155                   # in inch\n",
-      "sy = 42                     # Yeild stress of steel in Ksi\n",
-      "\n",
-      "#calculation\n",
-      "\n",
-      "smax = (P/A)*(1+(((e*c)/r**2)*mpmath.sec((L/(2*r))*math.sqrt(P/(E*A)))))           # Maximum compressive stress\n",
-      "print \"The Maximum compressive stress in the column \", round(smax,2), \"ksi\"\n",
-      "# Bisection method method to solve for yeilding\n",
-      "def stress(a,b,f):\n",
-      "    N = 100\n",
-      "    eps = 1e-5\n",
-      "    if((f(a)*f(b))>0):\n",
-      "        print 'no root possible f(a)*f(b)>0'\n",
-      "        sys.exit()\n",
-      "    if(abs(f(a))<eps):\n",
-      "        print 'solution at a'\n",
-      "        sys.exit()\n",
-      "    if(abs(f(b))<eps):\n",
-      "        print 'solution at b'\n",
-      "    while(N>0):\n",
-      "        c = (a+b)/2.0\n",
-      "        if(abs(f(c))<eps):\n",
-      "            x = c \n",
-      "            return x\n",
-      "        if((f(a)*f(c))<0 ):\n",
-      "            b = c \n",
-      "        else:\n",
-      "          a = c \n",
-      "        N = N-1\n",
-      "    print 'no convergence'\n",
-      "    sys.exit()\n",
-      "\n",
-      "def p(x): \n",
-      "\t return  x + (0.2939*x*sec(0.02916*sqrt(x))) - 1012 \n",
-      "x = stress(710,750,p)\n",
-      "Py = x                  # Yeilding load in K\n",
-      "n = Py/P                # Factor of safety against yeilding\n",
-      "print \"The factor of safety against yeilding is\", round(n)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The Maximum compressive stress in the column  19.32 ksi\n",
-        "The factor of safety against yeilding is 2.0\n"
-       ]
-      }
-     ],
-     "prompt_number": 7
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11.5, page no. 804"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "the allowable axial load & max. permissible length\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "import numpy\n",
-      "\n",
-      "#initialisation\n",
-      "E = 29000                       # Modulus of elasticity in ksi\n",
-      "sy = 36                         # Yeilding stress in ksi\n",
-      "L = 20                          # Length of coloumn in ft\n",
-      "r = 2.57                        # radius of gyration of coloumn\n",
-      "K = 1                           # Effetive Length factor\n",
-      "\n",
-      "#calculation\n",
-      "s = math.sqrt((2*math.pi**2*E)/sy)          # Criticle slenderness ratio (K*L)/r\n",
-      "s_ = (L*12)/r                               # Slenderness ratio\n",
-      "\n",
-      "# Part(a)\n",
-      "n1 = (5.0/3.0)+((3.0/8.0)*(s_/s))-((1.0/8.0)*((s_**3)/(s**3)))  # Factor of safety \n",
-      "sallow = (sy/n1)*(1-((1.0/2.0)*((s_**2)/(s**2))))               # Allowable axial load\n",
-      "A = 17.6                                                        # Cross sectional area from table E1\n",
-      "Pallow = sallow*A                                               # Allowable axial load\n",
-      "print \"Allowable axial load is\", round(Pallow,2), \"k\"\n",
-      "\n",
-      "# Part (b)\n",
-      "Pe = 200                        # Permissible load in K\n",
-      "L_ = 25                         # Assumed length in ft\n",
-      "s__ = (L_*12)/r                 # Slenderness ratio\n",
-      "n1_ = (5.0/3.0)+((3.0/8.0)*(s__/s))-((1.0/8.0)*((s__**3)/(s**3)))   # Factor of safety \n",
-      "sallow_ = (sy/n1_)*(1-((1.0/2.0)*((s__**2)/(s**2))))                # Allowable axial load\n",
-      "A = 17.6                                                            # Area of the cross section in**2\n",
-      "Pallow = sallow_*A                                                  # Allowable load\n",
-      "L1 = [24, 24.4, 25]\n",
-      "P1 = [201, 194, 190]\n",
-      "L_max = numpy.interp(200.0, P1, L1)\n",
-      "print \"The maximum permissible length is\", L_max, \"ft\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Allowable axial load is 242.84 k\n",
-        "The maximum permissible length is 25.0 ft\n"
-       ]
-      }
-     ],
-     "prompt_number": 8
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11.6, page no. 806"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math \n",
-      "import numpy\n",
-      "\n",
-      "#initialisation\n",
-      "L = 3.6                         # Length of steel pipe coloumn\n",
-      "d = 0.16                        # Outer diameter in m\n",
-      "P = 240e03                      # Load in N\n",
-      "E = 200e09                      # Modulus of elasticity in Pa\n",
-      "sy = 259e06                     # yeilding stress in Pa\n",
-      "K = 2.0\n",
-      "Le = K*L                        # As it in fixed-free condition\n",
-      "\n",
-      "#calculation\n",
-      "sc = math.sqrt((2*math.pi**2*E)/sy) # Critical slenderness ratio\n",
-      "\n",
-      "# First trial\n",
-      "t = 0.007                               # Assumed thick ness in m\n",
-      "I = (math.pi/64)*(d**4-(d-2*t)**4)      # Moment of inertia\n",
-      "A = (math.pi/4)*(d**2-(d-2*t)**2)       # Area of cross section\n",
-      "r = math.sqrt(I/A)                      # Radius of gyration\n",
-      "sc_ = round((K*L)/r)                           # Slender ness ratio\n",
-      "n2 = 1.92                               # From equation 11.80\n",
-      "sa = (sy/(2*n2))*(sc**2/sc_**2)         # Allowable stress\n",
-      "Pa = round((sa*A)/1000)                 # Allowable axial load in N\n",
-      "\n",
-      "# Interpolation\n",
-      "t = [7, 8, 9]\n",
-      "Pa = [196, 220, 243]\n",
-      "t_min = numpy.interp(240.0, Pa, t)\n",
-      "print \"The minimum required thickness of the steel pipe is\", round(t_min,1), \"mm\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "196.0\n",
-        "The minimum required thickness of the steel pipe is 8.9 mm\n"
-       ]
-      }
-     ],
-     "prompt_number": 17
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11.7, page no. 808"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "max. require outer diameter\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "\n",
-      "L = 16                          # Effective length in inch\n",
-      "P = 5                           # axial load in K\n",
-      "\n",
-      "#calculation\n",
-      "# Bisection method for solvong the quaderatic\n",
-      "def stress(a,b,f):\n",
-      "    N = 100\n",
-      "    eps = 1e-5\n",
-      "    if((f(a)*f(b))>0):\n",
-      "        print 'no root possible f(a)*f(b)>0'\n",
-      "        sys.exit()\n",
-      "    if(abs(f(a))<eps):\n",
-      "        print 'solution at a'\n",
-      "        sys.exit()\n",
-      "    if(abs(f(b))<eps):\n",
-      "        print 'solution at b'\n",
-      "    while(N>0):\n",
-      "        c = (a+b)/2.0\n",
-      "        if(abs(f(c))<eps):\n",
-      "            x = c \n",
-      "            return x\n",
-      "        if((f(a)*f(c))<0 ):\n",
-      "            b = c \n",
-      "        else:\n",
-      "          a = c \n",
-      "        N = N-1\n",
-      "    print 'no convergence'\n",
-      "    sys.exit()\n",
-      "def p(x): \n",
-      "\t return  30.7*x**2 - 11.49*x -17.69 \n",
-      "x = stress(0.9,1.1,p)\n",
-      "d = x                               # Diameter in inch\n",
-      "sl = 49.97/d                        # Slenderness ration L/r\n",
-      "dmin = d                            # Minimum diameter\n",
-      "print \"The minimum required outer diameter of the tube is\", round(dmin,2), \"inch\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The minimum required outer diameter of the tube is 0.97 inch\n"
-       ]
-      }
-     ],
-     "prompt_number": 11
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11.8, page no. 810"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculate various quantities\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "Fc = 11e06                          # Compressive demath.sing stress in Pa\n",
-      "E = 13e09                           # Modulus of elasticity in Pa\n",
-      "\n",
-      "#calculation\n",
-      "# Part (a)\n",
-      "Kce = 0.3  \n",
-      "c = 0.8 \n",
-      "A = 0.12*0.16                           # Area of cross section\n",
-      "Sl = 1.8/0.12                           # Slenderness ratio\n",
-      "fi = (Kce*E)/(Fc*Sl**2)                 # ratio of stresses\n",
-      "Cp = ((1+fi)/(2*c)) - math.sqrt(((1+fi)/(2*c))**2-(fi/c)) # Coloumn stability factor \n",
-      "Pa = Fc*Cp*A\n",
-      "print \"The allowable axial load is\", Pa, \"N\"\n",
-      "\n",
-      "# Part (b)\n",
-      "P = 100000                              # Allowable Axial load\n",
-      "Cp_ = P/(Fc*A)                          # Coloumn stability factor\n",
-      "\n",
-      "# Bisection method method to solve for fi\n",
-      "def stress(a,b,f):\n",
-      "    N = 100\n",
-      "    eps = 1e-5\n",
-      "    if((f(a)*f(b))>0):\n",
-      "        print 'no root possible f(a)*f(b)>0'\n",
-      "        sys.exit()\n",
-      "    if(abs(f(a))<eps):\n",
-      "        print 'solution at a'\n",
-      "        sys.exit()\n",
-      "    if(abs(f(b))<eps):\n",
-      "        print 'solution at b'\n",
-      "    while(N>0):\n",
-      "        c = (a+b)/2.0\n",
-      "        if(abs(f(c))<eps):\n",
-      "            x = c \n",
-      "            return x\n",
-      "        if((f(a)*f(c))<0 ):\n",
-      "            b = c \n",
-      "        else:\n",
-      "          a = c \n",
-      "        N = N-1\n",
-      "    print 'no convergence'\n",
-      "    sys.exit()\n",
-      "def p(x): \n",
-      "    return  ((1+x)/(2.0*c)) - math.sqrt(((1+x)/(2.0*c))**2-(x/c)) - Cp_ \n",
-      "x = stress(0.1,1.0,p) \n",
-      "fi_ = x\n",
-      "d_ = 0.12                               # Diameter in m\n",
-      "L_max = d_*math.sqrt((Kce*E)/(fi_*Fc))  # Maximum length in m\n",
-      "print \"The minimum allowable length is\", round(L_max,2), \"m\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The allowable axial load is 173444.30361 N\n",
-        "The minimum allowable length is 3.02 m\n"
-       ]
-      }
-     ],
-     "prompt_number": 12
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Testing_the_interface/chapter1_1.ipynb b/Testing_the_interface/chapter1_1.ipynb
deleted file mode 100755
index cf45a409..00000000
--- a/Testing_the_interface/chapter1_1.ipynb
+++ /dev/null
@@ -1,423 +0,0 @@
-{
- "metadata": {
-  "name": ""
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 1: Tension Comprssion and Shear"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.1, page no. 9"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "Find compressive stress and strain in the post\n",
-      "\"\"\"\n",
-      "\n",
-      "import math\n",
-      "\n",
-      "#initialisation\n",
-      "\n",
-      "d_1 = 4                 # inner diameter (inch)\n",
-      "d_2 = 4.5               #outer diameter (inch)\n",
-      "P = 26000               # pressure in pound\n",
-      "L = 16                  # Length of cylinder (inch)\n",
-      "my_del = 0.012             # shortening of post (inch)\n",
-      "\n",
-      "#calculation\n",
-      "A = (math.pi/4)*((d_2**2)-(d_1**2))     #Area (inch^2)\n",
-      "s = P/A                                 # stress\n",
-      "\n",
-      "print \"compressive stress in the post is \", round(s), \"psi\"\n",
-      "\n",
-      "e = my_del/L                            # strain\n",
-      "\n",
-      "print \"compressive strain in the post is %e\" %e"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "compressive stress in the post is  7789.0 psi\n",
-        "compressive strain in the post is 7.500000e-04\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.2, page no. 10"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "formula for maximum stress & calculating maximum stress\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "W = 1500                    # weight (Newton)\n",
-      "d = 0.008                   #diameter(meter) \n",
-      "g = 77000                   # Weight density of steel\n",
-      "L = 40                      # Length of bar (m)\n",
-      "\n",
-      "#calculation\n",
-      "\n",
-      "A = (math.pi/4)*(d**2)      # Area\n",
-      "s_max = (1500/A) + (g*L)    # maximum stress\n",
-      "\n",
-      "#result\n",
-      "print \"Therefore the maximum stress in the rod is \", round(s_max,1), \"Pa\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Therefore the maximum stress in the rod is  32921551.8 Pa\n"
-       ]
-      }
-     ],
-     "prompt_number": 16
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.3. page no. 26"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculating change in lenght of pipe, strain in pipe, increase in diameter & increase in wall thickness\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "d1 = 4.5                            # diameter in inch\n",
-      "d2 = 6                              # diameter in inch\n",
-      "A = (math.pi/4)*((d2**2)-(d1**2))   # Area\n",
-      "P = 140                             # pressure in K\n",
-      "s = -P/A                            # stress (compression)\n",
-      "E = 30000                           # young's modulus in Ksi\n",
-      "e = s/E                             # strain\n",
-      "\n",
-      "#calculation\n",
-      "\n",
-      "# Part (a)\n",
-      "my_del = e*4*12                        # del = e*L \n",
-      "print \"Change in length of the pipe is\", round(my_del,3), \"inch\"\n",
-      "\n",
-      "# Part (b)\n",
-      "v = 0.30                            # Poissio's ratio\n",
-      "e_ = -(v*e)\n",
-      "print \"Lateral strain in the pipe is %e\" %e_\n",
-      "\n",
-      "# Part (c)\n",
-      "del_d2 = e_*d2 \n",
-      "del_d1 = e_*d1\n",
-      "print \"Increase in the inner diameter is \", round(del_d1,6), \"inch\"\n",
-      "\n",
-      "# Part (d)\n",
-      "t = 0.75\n",
-      "del_t = e_*t\n",
-      "print \"Increase in the wall thicness is %f\" %del_t, \"inch\"\n",
-      "del_t1 = (del_d2-del_d1)/2 \n",
-      "print \"del_t1 = del_t\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Change in length of the pipe is -0.018 inch\n",
-        "Lateral strain in the pipe is 1.131768e-04\n",
-        "Increase in the inner diameter is  0.000509 inch\n",
-        "Increase in the wall thicness is 0.000085 inch\n",
-        "del_t1 = del_t\n"
-       ]
-      }
-     ],
-     "prompt_number": 7
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.4, page no. 35"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculate average shear stress and compressive stress\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "d = 0.02                            # diameter in m\n",
-      "t = 0.008                           # thickness in m\n",
-      "A = math.pi*d*t                     # shear area\n",
-      "P = 110000                          # prassure in Newton\n",
-      "\n",
-      "#calculation\n",
-      "A1 = (math.pi/4)*(d**2)             # Punch area\n",
-      "t_aver = P/A                        # Average shear stress \n",
-      "\n",
-      "\n",
-      "print \"Average shear stress in the plate is \", t_aver, \"Pa\"\n",
-      "s_c = P/A1  # compressive stress\n",
-      "print \"Average compressive stress in the plate is \", s_c, \"Pa\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Average shear stress in the plate is  218838046.751 Pa\n",
-        "Average compressive stress in the plate is  350140874.802 Pa\n"
-       ]
-      }
-     ],
-     "prompt_number": 37
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Eample 1.5, page no. 36"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculate bearing stress, shear stress in pin,\n",
-      "bearing stress between pin and gussets,\n",
-      "shear stress in anchor bolts\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "\n",
-      "P = 12.0                              # Pressure in K\n",
-      "t = 0.375                           # thickness of wall in inch\n",
-      "theta = 40.0                          # angle in degree\n",
-      "d_pin = 0.75                        # diameter of pin in inch\n",
-      "t_G = 0.625                         # thickness of gusset in inch\n",
-      "t_B = 0.375                         #thickness of base plate in inch\n",
-      "d_b = 0.50                          # diameter of bolt in inch\n",
-      "\n",
-      "#calculation\n",
-      "\n",
-      "#Part (a)\n",
-      "s_b1 = P/(2*t*d_pin)                  # bearing stress\n",
-      "print \"Bearing stress between strut and pin\", round(s_b1,1), \"ksi\"\n",
-      "\n",
-      "#Part (b)\n",
-      "t_pin = (4*P)/(2*math.pi*(d_pin**2))  # average shear stress in the \n",
-      "print \"Shear stress in pin is \", round(t_pin,1), \"ksi\"\n",
-      "\n",
-      "# Part (c)\n",
-      "s_b2 = P/(2*t_G*d_pin)                # bearing stress between pin and gusset\n",
-      "print \"Bearing stress between pin and gussets is\", s_b2, \"ksi\"\n",
-      "\n",
-      "# Part (d)\n",
-      "s_b3 = (P*math.cos(math.radians(40))/(4*t_B*d_b)) # bearing stress between anchor bolt and base plate\n",
-      "print \"Bearing stress between anchor bolts & base plate\", round(s_b3,1), \"ksi\"\n",
-      "\n",
-      "# Part (e)\n",
-      "t_bolt = (4*math.cos(math.radians(40))*P)/(4*math.pi*(d_b**2))  # shear stress in anchor bolt\n",
-      "print \"Shear stress in anchor bolts is\", round(t_bolt,1), \"ksi\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Bearing stress between strut and pin 21.3 ksi\n",
-        "Shear stress in pin is  13.6 ksi\n",
-        "Bearing stress between pin and gussets is 12.8 ksi\n",
-        "Bearing stress between anchor bolts & base plate 12.3 ksi\n",
-        "Shear stress in anchor bolts is 11.7 ksi\n"
-       ]
-      }
-     ],
-     "prompt_number": 39
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.7, page no. 42"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "determine stress at various parts\n",
-      "\"\"\"\n",
-      "\n",
-      "import math\n",
-      "\n",
-      "#initialisation\n",
-      "b1 = 1.5                            # width of recmath.tangular crosssection in inch\n",
-      "t = 0.5                             # thickness of recmath.tangular crosssection in inch\n",
-      "b2 = 3.0                            # width  of enlarged recmath.tangular crosssection in inch\n",
-      "d = 1.0                             # diameter in inch\n",
-      "\n",
-      "#calculation\n",
-      "\n",
-      "# Part (a)\n",
-      "s_1 = 16000 # maximum allowable tensile stress in Psi\n",
-      "P_1 = s_1*t*b1 \n",
-      "print \"The allowable load  P1 is\", P_1, \"lb\"\n",
-      "\n",
-      "# Part (b)\n",
-      "s_2 = 11000 # maximum allowable tensile stress in Psi\n",
-      "P_2 = s_2*t*(b2-d) \n",
-      "print \"allowable load P2 at this section is\", P_2, \"lb\"\n",
-      "\n",
-      "#Part (c)\n",
-      "s_3 = 26000 # maximum allowable tensile stress in Psi\n",
-      "P_3 = s_3*t*d \n",
-      "print \"The allowable load based upon bearing between the hanger and the bolt is\", P_3, \"lb\"\n",
-      "\n",
-      "# Part (d)\n",
-      "s_4 = 6500 # maximum allowable tensile stress in Psi\n",
-      "P_4 = (math.pi/4)*(d**2)*2*s_4 \n",
-      "print \"the allowable load  P4 based upon shear in the bolt is\", round(P_4), \"lb\"\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The allowable load  P1 is 12000.0 lb\n",
-        "allowable load P2 at this section is 11000.0 lb\n",
-        "The allowable load based upon bearing between the hanger and the bolt is 13000.0 lb\n",
-        "the allowable load  P4 based upon shear in the bolt is 10210.0 lb\n"
-       ]
-      }
-     ],
-     "prompt_number": 42
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.8, page no. 46"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculating the cross sectional area \n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "R_ah = (2700*0.8 + 2700*2.6)/2                  # Horizontal component at A in N\n",
-      "R_ch = R_ah                                     # Horizontal component at C in N\n",
-      "R_cv = (2700*2.2 + 2700*0.4)/3                  # vertical component at C in N\n",
-      "R_av = 2700 + 2700 - R_cv                       # vertical component at A in N\n",
-      "R_a = math.sqrt((R_ah**2)+(R_av**2))\n",
-      "R_c = math.sqrt((R_ch**2)+(R_cv**2))\n",
-      "Fab = R_a                                       # Tensile force in bar AB\n",
-      "Vc = R_c                                        # Shear force acting on the pin at C\n",
-      "s_allow = 125000000                             # allowable stress in tension \n",
-      "t_allow = 45000000                              # allowable stress in shear\n",
-      "\n",
-      "#calculation\n",
-      "Aab = Fab / s_allow                             # required area of bar \n",
-      "Apin = Vc / (2*t_allow)                         # required area of pin\n",
-      "\n",
-      "\n",
-      "print \"Required area of bar is %f\" %Apin, \"m^2\"\n",
-      "d = math.sqrt((4*Apin)/math.pi)                 # diameter in meter\n",
-      "print \"Required diameter of pin is %f\" %d, \"m\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Required area of bar is 0.000057 m^2\n",
-        "Required diameter of pin is 0.008537 m\n"
-       ]
-      }
-     ],
-     "prompt_number": 9
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [],
-     "language": "python",
-     "metadata": {},
-     "outputs": []
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Testing_the_interface/chapter1_2.ipynb b/Testing_the_interface/chapter1_2.ipynb
deleted file mode 100755
index cf45a409..00000000
--- a/Testing_the_interface/chapter1_2.ipynb
+++ /dev/null
@@ -1,423 +0,0 @@
-{
- "metadata": {
-  "name": ""
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 1: Tension Comprssion and Shear"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.1, page no. 9"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "Find compressive stress and strain in the post\n",
-      "\"\"\"\n",
-      "\n",
-      "import math\n",
-      "\n",
-      "#initialisation\n",
-      "\n",
-      "d_1 = 4                 # inner diameter (inch)\n",
-      "d_2 = 4.5               #outer diameter (inch)\n",
-      "P = 26000               # pressure in pound\n",
-      "L = 16                  # Length of cylinder (inch)\n",
-      "my_del = 0.012             # shortening of post (inch)\n",
-      "\n",
-      "#calculation\n",
-      "A = (math.pi/4)*((d_2**2)-(d_1**2))     #Area (inch^2)\n",
-      "s = P/A                                 # stress\n",
-      "\n",
-      "print \"compressive stress in the post is \", round(s), \"psi\"\n",
-      "\n",
-      "e = my_del/L                            # strain\n",
-      "\n",
-      "print \"compressive strain in the post is %e\" %e"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "compressive stress in the post is  7789.0 psi\n",
-        "compressive strain in the post is 7.500000e-04\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.2, page no. 10"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "formula for maximum stress & calculating maximum stress\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "W = 1500                    # weight (Newton)\n",
-      "d = 0.008                   #diameter(meter) \n",
-      "g = 77000                   # Weight density of steel\n",
-      "L = 40                      # Length of bar (m)\n",
-      "\n",
-      "#calculation\n",
-      "\n",
-      "A = (math.pi/4)*(d**2)      # Area\n",
-      "s_max = (1500/A) + (g*L)    # maximum stress\n",
-      "\n",
-      "#result\n",
-      "print \"Therefore the maximum stress in the rod is \", round(s_max,1), \"Pa\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Therefore the maximum stress in the rod is  32921551.8 Pa\n"
-       ]
-      }
-     ],
-     "prompt_number": 16
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.3. page no. 26"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculating change in lenght of pipe, strain in pipe, increase in diameter & increase in wall thickness\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "d1 = 4.5                            # diameter in inch\n",
-      "d2 = 6                              # diameter in inch\n",
-      "A = (math.pi/4)*((d2**2)-(d1**2))   # Area\n",
-      "P = 140                             # pressure in K\n",
-      "s = -P/A                            # stress (compression)\n",
-      "E = 30000                           # young's modulus in Ksi\n",
-      "e = s/E                             # strain\n",
-      "\n",
-      "#calculation\n",
-      "\n",
-      "# Part (a)\n",
-      "my_del = e*4*12                        # del = e*L \n",
-      "print \"Change in length of the pipe is\", round(my_del,3), \"inch\"\n",
-      "\n",
-      "# Part (b)\n",
-      "v = 0.30                            # Poissio's ratio\n",
-      "e_ = -(v*e)\n",
-      "print \"Lateral strain in the pipe is %e\" %e_\n",
-      "\n",
-      "# Part (c)\n",
-      "del_d2 = e_*d2 \n",
-      "del_d1 = e_*d1\n",
-      "print \"Increase in the inner diameter is \", round(del_d1,6), \"inch\"\n",
-      "\n",
-      "# Part (d)\n",
-      "t = 0.75\n",
-      "del_t = e_*t\n",
-      "print \"Increase in the wall thicness is %f\" %del_t, \"inch\"\n",
-      "del_t1 = (del_d2-del_d1)/2 \n",
-      "print \"del_t1 = del_t\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Change in length of the pipe is -0.018 inch\n",
-        "Lateral strain in the pipe is 1.131768e-04\n",
-        "Increase in the inner diameter is  0.000509 inch\n",
-        "Increase in the wall thicness is 0.000085 inch\n",
-        "del_t1 = del_t\n"
-       ]
-      }
-     ],
-     "prompt_number": 7
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.4, page no. 35"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculate average shear stress and compressive stress\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "d = 0.02                            # diameter in m\n",
-      "t = 0.008                           # thickness in m\n",
-      "A = math.pi*d*t                     # shear area\n",
-      "P = 110000                          # prassure in Newton\n",
-      "\n",
-      "#calculation\n",
-      "A1 = (math.pi/4)*(d**2)             # Punch area\n",
-      "t_aver = P/A                        # Average shear stress \n",
-      "\n",
-      "\n",
-      "print \"Average shear stress in the plate is \", t_aver, \"Pa\"\n",
-      "s_c = P/A1  # compressive stress\n",
-      "print \"Average compressive stress in the plate is \", s_c, \"Pa\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Average shear stress in the plate is  218838046.751 Pa\n",
-        "Average compressive stress in the plate is  350140874.802 Pa\n"
-       ]
-      }
-     ],
-     "prompt_number": 37
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Eample 1.5, page no. 36"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculate bearing stress, shear stress in pin,\n",
-      "bearing stress between pin and gussets,\n",
-      "shear stress in anchor bolts\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "\n",
-      "P = 12.0                              # Pressure in K\n",
-      "t = 0.375                           # thickness of wall in inch\n",
-      "theta = 40.0                          # angle in degree\n",
-      "d_pin = 0.75                        # diameter of pin in inch\n",
-      "t_G = 0.625                         # thickness of gusset in inch\n",
-      "t_B = 0.375                         #thickness of base plate in inch\n",
-      "d_b = 0.50                          # diameter of bolt in inch\n",
-      "\n",
-      "#calculation\n",
-      "\n",
-      "#Part (a)\n",
-      "s_b1 = P/(2*t*d_pin)                  # bearing stress\n",
-      "print \"Bearing stress between strut and pin\", round(s_b1,1), \"ksi\"\n",
-      "\n",
-      "#Part (b)\n",
-      "t_pin = (4*P)/(2*math.pi*(d_pin**2))  # average shear stress in the \n",
-      "print \"Shear stress in pin is \", round(t_pin,1), \"ksi\"\n",
-      "\n",
-      "# Part (c)\n",
-      "s_b2 = P/(2*t_G*d_pin)                # bearing stress between pin and gusset\n",
-      "print \"Bearing stress between pin and gussets is\", s_b2, \"ksi\"\n",
-      "\n",
-      "# Part (d)\n",
-      "s_b3 = (P*math.cos(math.radians(40))/(4*t_B*d_b)) # bearing stress between anchor bolt and base plate\n",
-      "print \"Bearing stress between anchor bolts & base plate\", round(s_b3,1), \"ksi\"\n",
-      "\n",
-      "# Part (e)\n",
-      "t_bolt = (4*math.cos(math.radians(40))*P)/(4*math.pi*(d_b**2))  # shear stress in anchor bolt\n",
-      "print \"Shear stress in anchor bolts is\", round(t_bolt,1), \"ksi\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Bearing stress between strut and pin 21.3 ksi\n",
-        "Shear stress in pin is  13.6 ksi\n",
-        "Bearing stress between pin and gussets is 12.8 ksi\n",
-        "Bearing stress between anchor bolts & base plate 12.3 ksi\n",
-        "Shear stress in anchor bolts is 11.7 ksi\n"
-       ]
-      }
-     ],
-     "prompt_number": 39
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.7, page no. 42"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "determine stress at various parts\n",
-      "\"\"\"\n",
-      "\n",
-      "import math\n",
-      "\n",
-      "#initialisation\n",
-      "b1 = 1.5                            # width of recmath.tangular crosssection in inch\n",
-      "t = 0.5                             # thickness of recmath.tangular crosssection in inch\n",
-      "b2 = 3.0                            # width  of enlarged recmath.tangular crosssection in inch\n",
-      "d = 1.0                             # diameter in inch\n",
-      "\n",
-      "#calculation\n",
-      "\n",
-      "# Part (a)\n",
-      "s_1 = 16000 # maximum allowable tensile stress in Psi\n",
-      "P_1 = s_1*t*b1 \n",
-      "print \"The allowable load  P1 is\", P_1, \"lb\"\n",
-      "\n",
-      "# Part (b)\n",
-      "s_2 = 11000 # maximum allowable tensile stress in Psi\n",
-      "P_2 = s_2*t*(b2-d) \n",
-      "print \"allowable load P2 at this section is\", P_2, \"lb\"\n",
-      "\n",
-      "#Part (c)\n",
-      "s_3 = 26000 # maximum allowable tensile stress in Psi\n",
-      "P_3 = s_3*t*d \n",
-      "print \"The allowable load based upon bearing between the hanger and the bolt is\", P_3, \"lb\"\n",
-      "\n",
-      "# Part (d)\n",
-      "s_4 = 6500 # maximum allowable tensile stress in Psi\n",
-      "P_4 = (math.pi/4)*(d**2)*2*s_4 \n",
-      "print \"the allowable load  P4 based upon shear in the bolt is\", round(P_4), \"lb\"\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The allowable load  P1 is 12000.0 lb\n",
-        "allowable load P2 at this section is 11000.0 lb\n",
-        "The allowable load based upon bearing between the hanger and the bolt is 13000.0 lb\n",
-        "the allowable load  P4 based upon shear in the bolt is 10210.0 lb\n"
-       ]
-      }
-     ],
-     "prompt_number": 42
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.8, page no. 46"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculating the cross sectional area \n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "R_ah = (2700*0.8 + 2700*2.6)/2                  # Horizontal component at A in N\n",
-      "R_ch = R_ah                                     # Horizontal component at C in N\n",
-      "R_cv = (2700*2.2 + 2700*0.4)/3                  # vertical component at C in N\n",
-      "R_av = 2700 + 2700 - R_cv                       # vertical component at A in N\n",
-      "R_a = math.sqrt((R_ah**2)+(R_av**2))\n",
-      "R_c = math.sqrt((R_ch**2)+(R_cv**2))\n",
-      "Fab = R_a                                       # Tensile force in bar AB\n",
-      "Vc = R_c                                        # Shear force acting on the pin at C\n",
-      "s_allow = 125000000                             # allowable stress in tension \n",
-      "t_allow = 45000000                              # allowable stress in shear\n",
-      "\n",
-      "#calculation\n",
-      "Aab = Fab / s_allow                             # required area of bar \n",
-      "Apin = Vc / (2*t_allow)                         # required area of pin\n",
-      "\n",
-      "\n",
-      "print \"Required area of bar is %f\" %Apin, \"m^2\"\n",
-      "d = math.sqrt((4*Apin)/math.pi)                 # diameter in meter\n",
-      "print \"Required diameter of pin is %f\" %d, \"m\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Required area of bar is 0.000057 m^2\n",
-        "Required diameter of pin is 0.008537 m\n"
-       ]
-      }
-     ],
-     "prompt_number": 9
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [],
-     "language": "python",
-     "metadata": {},
-     "outputs": []
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Testing_the_interface/chapter1_3.ipynb b/Testing_the_interface/chapter1_3.ipynb
deleted file mode 100755
index cf45a409..00000000
--- a/Testing_the_interface/chapter1_3.ipynb
+++ /dev/null
@@ -1,423 +0,0 @@
-{
- "metadata": {
-  "name": ""
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 1: Tension Comprssion and Shear"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.1, page no. 9"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "Find compressive stress and strain in the post\n",
-      "\"\"\"\n",
-      "\n",
-      "import math\n",
-      "\n",
-      "#initialisation\n",
-      "\n",
-      "d_1 = 4                 # inner diameter (inch)\n",
-      "d_2 = 4.5               #outer diameter (inch)\n",
-      "P = 26000               # pressure in pound\n",
-      "L = 16                  # Length of cylinder (inch)\n",
-      "my_del = 0.012             # shortening of post (inch)\n",
-      "\n",
-      "#calculation\n",
-      "A = (math.pi/4)*((d_2**2)-(d_1**2))     #Area (inch^2)\n",
-      "s = P/A                                 # stress\n",
-      "\n",
-      "print \"compressive stress in the post is \", round(s), \"psi\"\n",
-      "\n",
-      "e = my_del/L                            # strain\n",
-      "\n",
-      "print \"compressive strain in the post is %e\" %e"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "compressive stress in the post is  7789.0 psi\n",
-        "compressive strain in the post is 7.500000e-04\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.2, page no. 10"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "formula for maximum stress & calculating maximum stress\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "W = 1500                    # weight (Newton)\n",
-      "d = 0.008                   #diameter(meter) \n",
-      "g = 77000                   # Weight density of steel\n",
-      "L = 40                      # Length of bar (m)\n",
-      "\n",
-      "#calculation\n",
-      "\n",
-      "A = (math.pi/4)*(d**2)      # Area\n",
-      "s_max = (1500/A) + (g*L)    # maximum stress\n",
-      "\n",
-      "#result\n",
-      "print \"Therefore the maximum stress in the rod is \", round(s_max,1), \"Pa\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Therefore the maximum stress in the rod is  32921551.8 Pa\n"
-       ]
-      }
-     ],
-     "prompt_number": 16
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.3. page no. 26"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculating change in lenght of pipe, strain in pipe, increase in diameter & increase in wall thickness\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "d1 = 4.5                            # diameter in inch\n",
-      "d2 = 6                              # diameter in inch\n",
-      "A = (math.pi/4)*((d2**2)-(d1**2))   # Area\n",
-      "P = 140                             # pressure in K\n",
-      "s = -P/A                            # stress (compression)\n",
-      "E = 30000                           # young's modulus in Ksi\n",
-      "e = s/E                             # strain\n",
-      "\n",
-      "#calculation\n",
-      "\n",
-      "# Part (a)\n",
-      "my_del = e*4*12                        # del = e*L \n",
-      "print \"Change in length of the pipe is\", round(my_del,3), \"inch\"\n",
-      "\n",
-      "# Part (b)\n",
-      "v = 0.30                            # Poissio's ratio\n",
-      "e_ = -(v*e)\n",
-      "print \"Lateral strain in the pipe is %e\" %e_\n",
-      "\n",
-      "# Part (c)\n",
-      "del_d2 = e_*d2 \n",
-      "del_d1 = e_*d1\n",
-      "print \"Increase in the inner diameter is \", round(del_d1,6), \"inch\"\n",
-      "\n",
-      "# Part (d)\n",
-      "t = 0.75\n",
-      "del_t = e_*t\n",
-      "print \"Increase in the wall thicness is %f\" %del_t, \"inch\"\n",
-      "del_t1 = (del_d2-del_d1)/2 \n",
-      "print \"del_t1 = del_t\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Change in length of the pipe is -0.018 inch\n",
-        "Lateral strain in the pipe is 1.131768e-04\n",
-        "Increase in the inner diameter is  0.000509 inch\n",
-        "Increase in the wall thicness is 0.000085 inch\n",
-        "del_t1 = del_t\n"
-       ]
-      }
-     ],
-     "prompt_number": 7
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.4, page no. 35"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculate average shear stress and compressive stress\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "d = 0.02                            # diameter in m\n",
-      "t = 0.008                           # thickness in m\n",
-      "A = math.pi*d*t                     # shear area\n",
-      "P = 110000                          # prassure in Newton\n",
-      "\n",
-      "#calculation\n",
-      "A1 = (math.pi/4)*(d**2)             # Punch area\n",
-      "t_aver = P/A                        # Average shear stress \n",
-      "\n",
-      "\n",
-      "print \"Average shear stress in the plate is \", t_aver, \"Pa\"\n",
-      "s_c = P/A1  # compressive stress\n",
-      "print \"Average compressive stress in the plate is \", s_c, \"Pa\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Average shear stress in the plate is  218838046.751 Pa\n",
-        "Average compressive stress in the plate is  350140874.802 Pa\n"
-       ]
-      }
-     ],
-     "prompt_number": 37
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Eample 1.5, page no. 36"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculate bearing stress, shear stress in pin,\n",
-      "bearing stress between pin and gussets,\n",
-      "shear stress in anchor bolts\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "\n",
-      "P = 12.0                              # Pressure in K\n",
-      "t = 0.375                           # thickness of wall in inch\n",
-      "theta = 40.0                          # angle in degree\n",
-      "d_pin = 0.75                        # diameter of pin in inch\n",
-      "t_G = 0.625                         # thickness of gusset in inch\n",
-      "t_B = 0.375                         #thickness of base plate in inch\n",
-      "d_b = 0.50                          # diameter of bolt in inch\n",
-      "\n",
-      "#calculation\n",
-      "\n",
-      "#Part (a)\n",
-      "s_b1 = P/(2*t*d_pin)                  # bearing stress\n",
-      "print \"Bearing stress between strut and pin\", round(s_b1,1), \"ksi\"\n",
-      "\n",
-      "#Part (b)\n",
-      "t_pin = (4*P)/(2*math.pi*(d_pin**2))  # average shear stress in the \n",
-      "print \"Shear stress in pin is \", round(t_pin,1), \"ksi\"\n",
-      "\n",
-      "# Part (c)\n",
-      "s_b2 = P/(2*t_G*d_pin)                # bearing stress between pin and gusset\n",
-      "print \"Bearing stress between pin and gussets is\", s_b2, \"ksi\"\n",
-      "\n",
-      "# Part (d)\n",
-      "s_b3 = (P*math.cos(math.radians(40))/(4*t_B*d_b)) # bearing stress between anchor bolt and base plate\n",
-      "print \"Bearing stress between anchor bolts & base plate\", round(s_b3,1), \"ksi\"\n",
-      "\n",
-      "# Part (e)\n",
-      "t_bolt = (4*math.cos(math.radians(40))*P)/(4*math.pi*(d_b**2))  # shear stress in anchor bolt\n",
-      "print \"Shear stress in anchor bolts is\", round(t_bolt,1), \"ksi\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Bearing stress between strut and pin 21.3 ksi\n",
-        "Shear stress in pin is  13.6 ksi\n",
-        "Bearing stress between pin and gussets is 12.8 ksi\n",
-        "Bearing stress between anchor bolts & base plate 12.3 ksi\n",
-        "Shear stress in anchor bolts is 11.7 ksi\n"
-       ]
-      }
-     ],
-     "prompt_number": 39
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.7, page no. 42"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "determine stress at various parts\n",
-      "\"\"\"\n",
-      "\n",
-      "import math\n",
-      "\n",
-      "#initialisation\n",
-      "b1 = 1.5                            # width of recmath.tangular crosssection in inch\n",
-      "t = 0.5                             # thickness of recmath.tangular crosssection in inch\n",
-      "b2 = 3.0                            # width  of enlarged recmath.tangular crosssection in inch\n",
-      "d = 1.0                             # diameter in inch\n",
-      "\n",
-      "#calculation\n",
-      "\n",
-      "# Part (a)\n",
-      "s_1 = 16000 # maximum allowable tensile stress in Psi\n",
-      "P_1 = s_1*t*b1 \n",
-      "print \"The allowable load  P1 is\", P_1, \"lb\"\n",
-      "\n",
-      "# Part (b)\n",
-      "s_2 = 11000 # maximum allowable tensile stress in Psi\n",
-      "P_2 = s_2*t*(b2-d) \n",
-      "print \"allowable load P2 at this section is\", P_2, \"lb\"\n",
-      "\n",
-      "#Part (c)\n",
-      "s_3 = 26000 # maximum allowable tensile stress in Psi\n",
-      "P_3 = s_3*t*d \n",
-      "print \"The allowable load based upon bearing between the hanger and the bolt is\", P_3, \"lb\"\n",
-      "\n",
-      "# Part (d)\n",
-      "s_4 = 6500 # maximum allowable tensile stress in Psi\n",
-      "P_4 = (math.pi/4)*(d**2)*2*s_4 \n",
-      "print \"the allowable load  P4 based upon shear in the bolt is\", round(P_4), \"lb\"\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The allowable load  P1 is 12000.0 lb\n",
-        "allowable load P2 at this section is 11000.0 lb\n",
-        "The allowable load based upon bearing between the hanger and the bolt is 13000.0 lb\n",
-        "the allowable load  P4 based upon shear in the bolt is 10210.0 lb\n"
-       ]
-      }
-     ],
-     "prompt_number": 42
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.8, page no. 46"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculating the cross sectional area \n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "R_ah = (2700*0.8 + 2700*2.6)/2                  # Horizontal component at A in N\n",
-      "R_ch = R_ah                                     # Horizontal component at C in N\n",
-      "R_cv = (2700*2.2 + 2700*0.4)/3                  # vertical component at C in N\n",
-      "R_av = 2700 + 2700 - R_cv                       # vertical component at A in N\n",
-      "R_a = math.sqrt((R_ah**2)+(R_av**2))\n",
-      "R_c = math.sqrt((R_ch**2)+(R_cv**2))\n",
-      "Fab = R_a                                       # Tensile force in bar AB\n",
-      "Vc = R_c                                        # Shear force acting on the pin at C\n",
-      "s_allow = 125000000                             # allowable stress in tension \n",
-      "t_allow = 45000000                              # allowable stress in shear\n",
-      "\n",
-      "#calculation\n",
-      "Aab = Fab / s_allow                             # required area of bar \n",
-      "Apin = Vc / (2*t_allow)                         # required area of pin\n",
-      "\n",
-      "\n",
-      "print \"Required area of bar is %f\" %Apin, \"m^2\"\n",
-      "d = math.sqrt((4*Apin)/math.pi)                 # diameter in meter\n",
-      "print \"Required diameter of pin is %f\" %d, \"m\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Required area of bar is 0.000057 m^2\n",
-        "Required diameter of pin is 0.008537 m\n"
-       ]
-      }
-     ],
-     "prompt_number": 9
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [],
-     "language": "python",
-     "metadata": {},
-     "outputs": []
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Testing_the_interface/chapter2.ipynb b/Testing_the_interface/chapter2.ipynb
deleted file mode 100755
index c4e1ad0f..00000000
--- a/Testing_the_interface/chapter2.ipynb
+++ /dev/null
@@ -1,501 +0,0 @@
-{
- "metadata": {
-  "name": ""
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 2: Axially Loaded Members"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.1, page no. 72"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculating the number of revolutions for the nut\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "\n",
-      "W = 2.0                       #lb\n",
-      "b = 10.5                   #inch\n",
-      "c = 6.4                    #inch\n",
-      "k = 4.2                    #inch\n",
-      "p = 1.0/16.0                   #inch\n",
-      "\n",
-      "#calculation\n",
-      "\n",
-      "n = (W*b)/(c*k*p)          #inch\n",
-      "\n",
-      "#result\n",
-      "\n",
-      "print \" No. of revolution required = \", n, \"revolutions\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " No. of revolution required =  12.5 revolutions\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.2, page no. 74"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "finding maximum allowable load\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "import numpy\n",
-      "\n",
-      "#initialisation\n",
-      "\n",
-      "Fce_ = 2.0                    #dummy variable\n",
-      "Fbd_ = 3.0                    #dummy variable    \n",
-      "Lbd = 480.0                   #mm\n",
-      "Lce = 600.0                  #mm\n",
-      "E = 205e6                   #205Gpa\n",
-      "Abd = 1020.0                  #mm\n",
-      "Ace = 520.0                   #mm\n",
-      "\n",
-      "#calculation\n",
-      "Dbd_ = (Fbd_*Lbd)/(E*Abd)   #dummy variable\n",
-      "Dce_ = (Fce_*Lce)/(E*Ace)   #dummy variable\n",
-      "Da = 1 #limiting value\n",
-      "P = ((((450+225)/225)*(Dbd_ + Dce_) - Dce_ )**(-1)) * Da  \n",
-      "Fce = 2*P # Real value in newton\n",
-      "Fbd = 3*P #real value in newton\n",
-      "Dbd = (Fbd*Lbd)/(E*Abd) #print lacement in mm\n",
-      "Dce = (Fce*Lce)/(E*Ace) # print lacement in mm\n",
-      "a = numpy.degrees(numpy.arctan(((Da+Dce)/675)))  #alpha in degree\n",
-      "\n",
-      "#result\n",
-      "print \"alpha = \", round(a,2), \"degree\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "alpha =  0.11 degree\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.3, page no. 80"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculation if vertical displacement\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "P1 = 2100.0                       #lb\n",
-      "P2 = 5600.0                       #lb\n",
-      "b = 25.0                          #inch\n",
-      "a = 28.0                          #inch\n",
-      "A1 = 0.25                       #inch^2\n",
-      "A2 = 0.15                       #inch^2\n",
-      "L1 = 20.0                         #inch\n",
-      "L2 = 34.8                       #inch\n",
-      "E = 29e6                        #29Gpa\n",
-      "\n",
-      "#Calculations\n",
-      "P3 = (P2*b)/a \n",
-      "Ra = P3-P1\n",
-      "N1 = -Ra \n",
-      "N2 = P1 \n",
-      "D = ((N1*L1)/(E*A1)) + ((N2*L2)/(E*A2))     #print lacement\n",
-      "\n",
-      "#Result\n",
-      "print  \"Downward print lacement is = \", D, \"inch\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Downward print lacement is =  0.0088 inch\n"
-       ]
-      }
-     ],
-     "prompt_number": 4
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.6, page no. 90"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "obtaing formula and calculating allowable load\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#Numerical calculation of allowable load\n",
-      "\n",
-      "d1 = 4.0                      #mm\n",
-      "d2 = 3.0                      #mm\n",
-      "A1 = (math.pi*(d1**2))/4    #area\n",
-      "A2 = (math.pi*(d2**2))/4    #area\n",
-      "L1 = 0.4                    #meter\n",
-      "L2 = 0.3                    #meter\n",
-      "E1 = 72e9                   #Gpa\n",
-      "E2 = 45e9                   #Gpa\n",
-      "f1 = L1/(E1*A1) * 1e6       # To cpmpensate for the mm**2\n",
-      "f2 = L2/(E2*A2) * 1e6 \n",
-      "s1 = 200e6                  #stress\n",
-      "s2 = 175e6                  #stress\n",
-      "\n",
-      "#Calculations\n",
-      "P1 = ( (s1*A1*(4*f1 + f2))/(3*f2) ) * 1e-6      # To cpmpensate for the mm**2\n",
-      "P2 = ( (s2*A2*(4*f1 + f2))/(6*f1) ) * 1e-6 \n",
-      "\n",
-      "#Result\n",
-      "print \"Newton Minimum allowable stress aomong the two P1 and P2 is smaller one, therefore MAS = \", P2"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Newton Minimum allowable stress aomong the two P1 and P2 is smaller one, therefore MAS =  1264.49104307\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.10, page no. 113"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculate stress acting on inclined section &\n",
-      "the complete state of stress\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "P = 90000.0                   #newton\n",
-      "A = 1200e-6                   # meter^2\n",
-      "s_x = -P/A                    #stress\n",
-      "t_1 = 25.0                    #for the stresses on ab and cd plane\n",
-      "\n",
-      "#Calculations\n",
-      "s_1 = s_x*(math.cos(math.radians(t_1))**2)\n",
-      "T_1 = -s_x*math.cos(math.radians(t_1))*math.sin(math.radians(t_1))\n",
-      "t_2 = -65.0                   #for the stresses on ad and bc plane\n",
-      "s_2 = s_x*(math.cos(math.radians(t_2))**2)\n",
-      "T_2 = -s_x*math.cos(math.radians(t_2))*math.sin(math.radians(t_2))\n",
-      "\n",
-      "#Result\n",
-      "print \"The normal and shear stresses on the plane ab and cd are\", round((T_1/1E+6),2), round((s_1/1E+6),2), \"MPa respecively\" \n",
-      "print \"respecively The normal and shear stresses on the plane ad and bc are\", round((T_2/1E+6),2), round((s_2/1E+6),2), \"MPa respecively\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The normal and shear stresses on the plane ab and cd are 28.73 -61.6 MPa respecively\n",
-        "respecively The normal and shear stresses on the plane ad and bc are -28.73 -13.4 MPa respecively\n"
-       ]
-      }
-     ],
-     "prompt_number": 4
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.11, page no. 114"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "Calculate the vertical displacement of the joint\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "# Value of s_x based on allowable stresses on glued joint\n",
-      "\n",
-      "#initialisation\n",
-      "s_t = -750.0                                  #psi\n",
-      "t = -50.0                                     #degree\n",
-      "T_t = -500.0                                  #psi\n",
-      "\n",
-      "sg_x_1 = s_t/(math.cos(math.radians(t))**2)\n",
-      "sg_x_2 = -T_t/(math.cos(math.radians(t))*math.sin(math.radians(t)))\n",
-      "\n",
-      "# Value of s_x based on allowable stresses on plastic\n",
-      "\n",
-      "sp_x_1 = -1100.0                              #psi\n",
-      "T_t_p = 600.0                                  #psi\n",
-      "t_p = 45.0                                    #degree\n",
-      "sp_x_2 = -T_t_p/(math.cos(math.radians(t_p))*math.sin(math.radians(t_p)))\n",
-      "\n",
-      "# Minimum width of bar\n",
-      "\n",
-      "P = 8000.0                                    #lb\n",
-      "A = P/sg_x_2\n",
-      "b_min = math.sqrt(abs(A))                        #inch\n",
-      "print \"The minimum width of the bar is\", round(b_min,2), \"inch\"\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The minimum width of the bar is 2.81 inch\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.15, page no. 126"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "Comparison of energy-absorbing capacity with different type of bolts\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "#Bolt with reduced shank diameter\n",
-      "\n",
-      "#initialisation\n",
-      "g = 1.50                     # inch\n",
-      "d = 0.5                      #inch\n",
-      "t = 0.25                     #inch\n",
-      "d_r = 0.406                  #inch\n",
-      "L = 13.5                     #inch\n",
-      "\n",
-      "#calculation\n",
-      "ratio = ((g*(d**2))/(((g-t)*(d_r**2))+(t*(d**2))))              #U2/U1\n",
-      "\n",
-      "print \"The energy absorbing capacity of the bolts with reduced shank diameter\", round(ratio,2)\n",
-      "ratio_1 = ( (((L-t)*(d_r**2))+(t*(d**2))) / ((2*(g-t)*(d_r**2))+2*(t*(d**2))) )         #U3/2U1\n",
-      "print \"The energy absorbing capacity of the long bolts\", round(ratio_1,2)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The energy absorbing capacity of the bolts with reduced shank diameter 1.4\n",
-        "The energy absorbing capacity of the long bolts 4.18\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "    Example 2.16, page no. 133"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "Determine the maximum elongation and tensile stress\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "# Maximum elongation\n",
-      "M = 20                      #kg\n",
-      "g = 9.81                    #m/s^2\n",
-      "L = 2                       #meter\n",
-      "E = 210e9                   #210Gpa\n",
-      "h = 0.15                    #meter\n",
-      "diameter = 0.015            #milimeter\n",
-      "\n",
-      "#Calculations & Result\n",
-      "A = (math.pi/4)*(diameter**2)               #area\n",
-      "D_st = ((M*g*L)/(E*A)) \n",
-      "D_max = D_st*(1+(1+(2*h/D_st))**0.5) \n",
-      "D_max_1 = math.sqrt(2*h*D_st)                # another approach to find D_max\n",
-      "i = D_max / D_st                             # Impact factor\n",
-      "print \"Maximum elongation is\",round((D_max/1E-3),2), \"mm\"  # Maximum tensile stress\n",
-      "s_max = (E*D_max)/L                          #Maximum tensile stress\n",
-      "s_st = (M*g)/A                               #static stress\n",
-      "i_1 = s_max / s_st                           #Impact factor \n",
-      "print \"Maximum tensile stress is \", round((s_max/1E+6),2), \"MPa\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum elongation is 1.79 mm\n",
-        "Maximum tensile stress is  188.13 MPa\n"
-       ]
-      }
-     ],
-     "prompt_number": 7
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.18, page no. 148"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "determine displacement at the lower end of bar in various conditions\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "\n",
-      "#initialisation\n",
-      "P1 = 108000.0                 #Newton\n",
-      "P2 = 27000.0                  #Newton\n",
-      "L = 2.2                     #meter\n",
-      "A = 480.0                     #mm^2\n",
-      "\n",
-      "\n",
-      "#calculations\n",
-      "\n",
-      "# Displacement due to load P1 acting alone\n",
-      "s = (P1/A)                      #stress in MPa\n",
-      "e = (s/70000) + (1/628.2)*((s/260)**10)         #strain\n",
-      "D_b = e*L*1e3                                   #elongation in mm\n",
-      "print \"elongation when only P1 load acting is = \", round(D_b,2), \" mm\"\n",
-      "\n",
-      "# Displacement due to load P2 acting alone\n",
-      "s_1 = (P2/A) #stress in MPa\n",
-      "e_1 = (s_1/70000) + (1/628.2)*((s_1/260)**10) #strain\n",
-      "D_b_1 = e_1*(L/2)*1e3 #elongation in mm (no elongation in lower half)\n",
-      "print \"elongation when only P2 load acting is = \", round(D_b_1,2), \" mm\"\n",
-      "\n",
-      "# Displacement due to both load acting simonmath.taneously\n",
-      "#upper half\n",
-      "s_2 = (P1/A) #stress in MPa\n",
-      "e_2 = (s_2/70000) + (1/628.2)*((s_2/260)**10) #strain\n",
-      "\n",
-      "#lower half\n",
-      "s_3 = (P1+P2)/A #stress in MPa\n",
-      "e_3 = (s_3/70000) + (1/628.2)*((s_3/260)**10) #strain\n",
-      "D_b_2 = ((e_2*L)/2 + (e_3*L)/2) * 1e3 # elongation in mm\n",
-      "print \"elongation when P1 and P2 both loads are acting is = \", round(D_b_2,2), \" mm\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "elongation when only P1 load acting is =  7.9  mm\n",
-        "elongation when only P2 load acting is =  0.88  mm\n",
-        "elongation when P1 and P2 both loads are acting is =  12.21  mm\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Testing_the_interface/chapter2_1.ipynb b/Testing_the_interface/chapter2_1.ipynb
deleted file mode 100755
index c4e1ad0f..00000000
--- a/Testing_the_interface/chapter2_1.ipynb
+++ /dev/null
@@ -1,501 +0,0 @@
-{
- "metadata": {
-  "name": ""
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 2: Axially Loaded Members"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.1, page no. 72"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculating the number of revolutions for the nut\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "\n",
-      "W = 2.0                       #lb\n",
-      "b = 10.5                   #inch\n",
-      "c = 6.4                    #inch\n",
-      "k = 4.2                    #inch\n",
-      "p = 1.0/16.0                   #inch\n",
-      "\n",
-      "#calculation\n",
-      "\n",
-      "n = (W*b)/(c*k*p)          #inch\n",
-      "\n",
-      "#result\n",
-      "\n",
-      "print \" No. of revolution required = \", n, \"revolutions\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " No. of revolution required =  12.5 revolutions\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.2, page no. 74"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "finding maximum allowable load\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "import numpy\n",
-      "\n",
-      "#initialisation\n",
-      "\n",
-      "Fce_ = 2.0                    #dummy variable\n",
-      "Fbd_ = 3.0                    #dummy variable    \n",
-      "Lbd = 480.0                   #mm\n",
-      "Lce = 600.0                  #mm\n",
-      "E = 205e6                   #205Gpa\n",
-      "Abd = 1020.0                  #mm\n",
-      "Ace = 520.0                   #mm\n",
-      "\n",
-      "#calculation\n",
-      "Dbd_ = (Fbd_*Lbd)/(E*Abd)   #dummy variable\n",
-      "Dce_ = (Fce_*Lce)/(E*Ace)   #dummy variable\n",
-      "Da = 1 #limiting value\n",
-      "P = ((((450+225)/225)*(Dbd_ + Dce_) - Dce_ )**(-1)) * Da  \n",
-      "Fce = 2*P # Real value in newton\n",
-      "Fbd = 3*P #real value in newton\n",
-      "Dbd = (Fbd*Lbd)/(E*Abd) #print lacement in mm\n",
-      "Dce = (Fce*Lce)/(E*Ace) # print lacement in mm\n",
-      "a = numpy.degrees(numpy.arctan(((Da+Dce)/675)))  #alpha in degree\n",
-      "\n",
-      "#result\n",
-      "print \"alpha = \", round(a,2), \"degree\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "alpha =  0.11 degree\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.3, page no. 80"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculation if vertical displacement\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "P1 = 2100.0                       #lb\n",
-      "P2 = 5600.0                       #lb\n",
-      "b = 25.0                          #inch\n",
-      "a = 28.0                          #inch\n",
-      "A1 = 0.25                       #inch^2\n",
-      "A2 = 0.15                       #inch^2\n",
-      "L1 = 20.0                         #inch\n",
-      "L2 = 34.8                       #inch\n",
-      "E = 29e6                        #29Gpa\n",
-      "\n",
-      "#Calculations\n",
-      "P3 = (P2*b)/a \n",
-      "Ra = P3-P1\n",
-      "N1 = -Ra \n",
-      "N2 = P1 \n",
-      "D = ((N1*L1)/(E*A1)) + ((N2*L2)/(E*A2))     #print lacement\n",
-      "\n",
-      "#Result\n",
-      "print  \"Downward print lacement is = \", D, \"inch\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Downward print lacement is =  0.0088 inch\n"
-       ]
-      }
-     ],
-     "prompt_number": 4
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.6, page no. 90"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "obtaing formula and calculating allowable load\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#Numerical calculation of allowable load\n",
-      "\n",
-      "d1 = 4.0                      #mm\n",
-      "d2 = 3.0                      #mm\n",
-      "A1 = (math.pi*(d1**2))/4    #area\n",
-      "A2 = (math.pi*(d2**2))/4    #area\n",
-      "L1 = 0.4                    #meter\n",
-      "L2 = 0.3                    #meter\n",
-      "E1 = 72e9                   #Gpa\n",
-      "E2 = 45e9                   #Gpa\n",
-      "f1 = L1/(E1*A1) * 1e6       # To cpmpensate for the mm**2\n",
-      "f2 = L2/(E2*A2) * 1e6 \n",
-      "s1 = 200e6                  #stress\n",
-      "s2 = 175e6                  #stress\n",
-      "\n",
-      "#Calculations\n",
-      "P1 = ( (s1*A1*(4*f1 + f2))/(3*f2) ) * 1e-6      # To cpmpensate for the mm**2\n",
-      "P2 = ( (s2*A2*(4*f1 + f2))/(6*f1) ) * 1e-6 \n",
-      "\n",
-      "#Result\n",
-      "print \"Newton Minimum allowable stress aomong the two P1 and P2 is smaller one, therefore MAS = \", P2"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Newton Minimum allowable stress aomong the two P1 and P2 is smaller one, therefore MAS =  1264.49104307\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.10, page no. 113"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculate stress acting on inclined section &\n",
-      "the complete state of stress\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "P = 90000.0                   #newton\n",
-      "A = 1200e-6                   # meter^2\n",
-      "s_x = -P/A                    #stress\n",
-      "t_1 = 25.0                    #for the stresses on ab and cd plane\n",
-      "\n",
-      "#Calculations\n",
-      "s_1 = s_x*(math.cos(math.radians(t_1))**2)\n",
-      "T_1 = -s_x*math.cos(math.radians(t_1))*math.sin(math.radians(t_1))\n",
-      "t_2 = -65.0                   #for the stresses on ad and bc plane\n",
-      "s_2 = s_x*(math.cos(math.radians(t_2))**2)\n",
-      "T_2 = -s_x*math.cos(math.radians(t_2))*math.sin(math.radians(t_2))\n",
-      "\n",
-      "#Result\n",
-      "print \"The normal and shear stresses on the plane ab and cd are\", round((T_1/1E+6),2), round((s_1/1E+6),2), \"MPa respecively\" \n",
-      "print \"respecively The normal and shear stresses on the plane ad and bc are\", round((T_2/1E+6),2), round((s_2/1E+6),2), \"MPa respecively\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The normal and shear stresses on the plane ab and cd are 28.73 -61.6 MPa respecively\n",
-        "respecively The normal and shear stresses on the plane ad and bc are -28.73 -13.4 MPa respecively\n"
-       ]
-      }
-     ],
-     "prompt_number": 4
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.11, page no. 114"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "Calculate the vertical displacement of the joint\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "# Value of s_x based on allowable stresses on glued joint\n",
-      "\n",
-      "#initialisation\n",
-      "s_t = -750.0                                  #psi\n",
-      "t = -50.0                                     #degree\n",
-      "T_t = -500.0                                  #psi\n",
-      "\n",
-      "sg_x_1 = s_t/(math.cos(math.radians(t))**2)\n",
-      "sg_x_2 = -T_t/(math.cos(math.radians(t))*math.sin(math.radians(t)))\n",
-      "\n",
-      "# Value of s_x based on allowable stresses on plastic\n",
-      "\n",
-      "sp_x_1 = -1100.0                              #psi\n",
-      "T_t_p = 600.0                                  #psi\n",
-      "t_p = 45.0                                    #degree\n",
-      "sp_x_2 = -T_t_p/(math.cos(math.radians(t_p))*math.sin(math.radians(t_p)))\n",
-      "\n",
-      "# Minimum width of bar\n",
-      "\n",
-      "P = 8000.0                                    #lb\n",
-      "A = P/sg_x_2\n",
-      "b_min = math.sqrt(abs(A))                        #inch\n",
-      "print \"The minimum width of the bar is\", round(b_min,2), \"inch\"\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The minimum width of the bar is 2.81 inch\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.15, page no. 126"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "Comparison of energy-absorbing capacity with different type of bolts\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "#Bolt with reduced shank diameter\n",
-      "\n",
-      "#initialisation\n",
-      "g = 1.50                     # inch\n",
-      "d = 0.5                      #inch\n",
-      "t = 0.25                     #inch\n",
-      "d_r = 0.406                  #inch\n",
-      "L = 13.5                     #inch\n",
-      "\n",
-      "#calculation\n",
-      "ratio = ((g*(d**2))/(((g-t)*(d_r**2))+(t*(d**2))))              #U2/U1\n",
-      "\n",
-      "print \"The energy absorbing capacity of the bolts with reduced shank diameter\", round(ratio,2)\n",
-      "ratio_1 = ( (((L-t)*(d_r**2))+(t*(d**2))) / ((2*(g-t)*(d_r**2))+2*(t*(d**2))) )         #U3/2U1\n",
-      "print \"The energy absorbing capacity of the long bolts\", round(ratio_1,2)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The energy absorbing capacity of the bolts with reduced shank diameter 1.4\n",
-        "The energy absorbing capacity of the long bolts 4.18\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "    Example 2.16, page no. 133"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "Determine the maximum elongation and tensile stress\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "# Maximum elongation\n",
-      "M = 20                      #kg\n",
-      "g = 9.81                    #m/s^2\n",
-      "L = 2                       #meter\n",
-      "E = 210e9                   #210Gpa\n",
-      "h = 0.15                    #meter\n",
-      "diameter = 0.015            #milimeter\n",
-      "\n",
-      "#Calculations & Result\n",
-      "A = (math.pi/4)*(diameter**2)               #area\n",
-      "D_st = ((M*g*L)/(E*A)) \n",
-      "D_max = D_st*(1+(1+(2*h/D_st))**0.5) \n",
-      "D_max_1 = math.sqrt(2*h*D_st)                # another approach to find D_max\n",
-      "i = D_max / D_st                             # Impact factor\n",
-      "print \"Maximum elongation is\",round((D_max/1E-3),2), \"mm\"  # Maximum tensile stress\n",
-      "s_max = (E*D_max)/L                          #Maximum tensile stress\n",
-      "s_st = (M*g)/A                               #static stress\n",
-      "i_1 = s_max / s_st                           #Impact factor \n",
-      "print \"Maximum tensile stress is \", round((s_max/1E+6),2), \"MPa\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum elongation is 1.79 mm\n",
-        "Maximum tensile stress is  188.13 MPa\n"
-       ]
-      }
-     ],
-     "prompt_number": 7
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.18, page no. 148"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "determine displacement at the lower end of bar in various conditions\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "\n",
-      "#initialisation\n",
-      "P1 = 108000.0                 #Newton\n",
-      "P2 = 27000.0                  #Newton\n",
-      "L = 2.2                     #meter\n",
-      "A = 480.0                     #mm^2\n",
-      "\n",
-      "\n",
-      "#calculations\n",
-      "\n",
-      "# Displacement due to load P1 acting alone\n",
-      "s = (P1/A)                      #stress in MPa\n",
-      "e = (s/70000) + (1/628.2)*((s/260)**10)         #strain\n",
-      "D_b = e*L*1e3                                   #elongation in mm\n",
-      "print \"elongation when only P1 load acting is = \", round(D_b,2), \" mm\"\n",
-      "\n",
-      "# Displacement due to load P2 acting alone\n",
-      "s_1 = (P2/A) #stress in MPa\n",
-      "e_1 = (s_1/70000) + (1/628.2)*((s_1/260)**10) #strain\n",
-      "D_b_1 = e_1*(L/2)*1e3 #elongation in mm (no elongation in lower half)\n",
-      "print \"elongation when only P2 load acting is = \", round(D_b_1,2), \" mm\"\n",
-      "\n",
-      "# Displacement due to both load acting simonmath.taneously\n",
-      "#upper half\n",
-      "s_2 = (P1/A) #stress in MPa\n",
-      "e_2 = (s_2/70000) + (1/628.2)*((s_2/260)**10) #strain\n",
-      "\n",
-      "#lower half\n",
-      "s_3 = (P1+P2)/A #stress in MPa\n",
-      "e_3 = (s_3/70000) + (1/628.2)*((s_3/260)**10) #strain\n",
-      "D_b_2 = ((e_2*L)/2 + (e_3*L)/2) * 1e3 # elongation in mm\n",
-      "print \"elongation when P1 and P2 both loads are acting is = \", round(D_b_2,2), \" mm\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "elongation when only P1 load acting is =  7.9  mm\n",
-        "elongation when only P2 load acting is =  0.88  mm\n",
-        "elongation when P1 and P2 both loads are acting is =  12.21  mm\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Testing_the_interface/chapter2_2.ipynb b/Testing_the_interface/chapter2_2.ipynb
deleted file mode 100755
index c4e1ad0f..00000000
--- a/Testing_the_interface/chapter2_2.ipynb
+++ /dev/null
@@ -1,501 +0,0 @@
-{
- "metadata": {
-  "name": ""
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 2: Axially Loaded Members"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.1, page no. 72"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculating the number of revolutions for the nut\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "\n",
-      "W = 2.0                       #lb\n",
-      "b = 10.5                   #inch\n",
-      "c = 6.4                    #inch\n",
-      "k = 4.2                    #inch\n",
-      "p = 1.0/16.0                   #inch\n",
-      "\n",
-      "#calculation\n",
-      "\n",
-      "n = (W*b)/(c*k*p)          #inch\n",
-      "\n",
-      "#result\n",
-      "\n",
-      "print \" No. of revolution required = \", n, \"revolutions\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " No. of revolution required =  12.5 revolutions\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.2, page no. 74"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "finding maximum allowable load\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "import numpy\n",
-      "\n",
-      "#initialisation\n",
-      "\n",
-      "Fce_ = 2.0                    #dummy variable\n",
-      "Fbd_ = 3.0                    #dummy variable    \n",
-      "Lbd = 480.0                   #mm\n",
-      "Lce = 600.0                  #mm\n",
-      "E = 205e6                   #205Gpa\n",
-      "Abd = 1020.0                  #mm\n",
-      "Ace = 520.0                   #mm\n",
-      "\n",
-      "#calculation\n",
-      "Dbd_ = (Fbd_*Lbd)/(E*Abd)   #dummy variable\n",
-      "Dce_ = (Fce_*Lce)/(E*Ace)   #dummy variable\n",
-      "Da = 1 #limiting value\n",
-      "P = ((((450+225)/225)*(Dbd_ + Dce_) - Dce_ )**(-1)) * Da  \n",
-      "Fce = 2*P # Real value in newton\n",
-      "Fbd = 3*P #real value in newton\n",
-      "Dbd = (Fbd*Lbd)/(E*Abd) #print lacement in mm\n",
-      "Dce = (Fce*Lce)/(E*Ace) # print lacement in mm\n",
-      "a = numpy.degrees(numpy.arctan(((Da+Dce)/675)))  #alpha in degree\n",
-      "\n",
-      "#result\n",
-      "print \"alpha = \", round(a,2), \"degree\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "alpha =  0.11 degree\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.3, page no. 80"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculation if vertical displacement\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "P1 = 2100.0                       #lb\n",
-      "P2 = 5600.0                       #lb\n",
-      "b = 25.0                          #inch\n",
-      "a = 28.0                          #inch\n",
-      "A1 = 0.25                       #inch^2\n",
-      "A2 = 0.15                       #inch^2\n",
-      "L1 = 20.0                         #inch\n",
-      "L2 = 34.8                       #inch\n",
-      "E = 29e6                        #29Gpa\n",
-      "\n",
-      "#Calculations\n",
-      "P3 = (P2*b)/a \n",
-      "Ra = P3-P1\n",
-      "N1 = -Ra \n",
-      "N2 = P1 \n",
-      "D = ((N1*L1)/(E*A1)) + ((N2*L2)/(E*A2))     #print lacement\n",
-      "\n",
-      "#Result\n",
-      "print  \"Downward print lacement is = \", D, \"inch\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Downward print lacement is =  0.0088 inch\n"
-       ]
-      }
-     ],
-     "prompt_number": 4
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.6, page no. 90"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "obtaing formula and calculating allowable load\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#Numerical calculation of allowable load\n",
-      "\n",
-      "d1 = 4.0                      #mm\n",
-      "d2 = 3.0                      #mm\n",
-      "A1 = (math.pi*(d1**2))/4    #area\n",
-      "A2 = (math.pi*(d2**2))/4    #area\n",
-      "L1 = 0.4                    #meter\n",
-      "L2 = 0.3                    #meter\n",
-      "E1 = 72e9                   #Gpa\n",
-      "E2 = 45e9                   #Gpa\n",
-      "f1 = L1/(E1*A1) * 1e6       # To cpmpensate for the mm**2\n",
-      "f2 = L2/(E2*A2) * 1e6 \n",
-      "s1 = 200e6                  #stress\n",
-      "s2 = 175e6                  #stress\n",
-      "\n",
-      "#Calculations\n",
-      "P1 = ( (s1*A1*(4*f1 + f2))/(3*f2) ) * 1e-6      # To cpmpensate for the mm**2\n",
-      "P2 = ( (s2*A2*(4*f1 + f2))/(6*f1) ) * 1e-6 \n",
-      "\n",
-      "#Result\n",
-      "print \"Newton Minimum allowable stress aomong the two P1 and P2 is smaller one, therefore MAS = \", P2"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Newton Minimum allowable stress aomong the two P1 and P2 is smaller one, therefore MAS =  1264.49104307\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.10, page no. 113"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculate stress acting on inclined section &\n",
-      "the complete state of stress\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "P = 90000.0                   #newton\n",
-      "A = 1200e-6                   # meter^2\n",
-      "s_x = -P/A                    #stress\n",
-      "t_1 = 25.0                    #for the stresses on ab and cd plane\n",
-      "\n",
-      "#Calculations\n",
-      "s_1 = s_x*(math.cos(math.radians(t_1))**2)\n",
-      "T_1 = -s_x*math.cos(math.radians(t_1))*math.sin(math.radians(t_1))\n",
-      "t_2 = -65.0                   #for the stresses on ad and bc plane\n",
-      "s_2 = s_x*(math.cos(math.radians(t_2))**2)\n",
-      "T_2 = -s_x*math.cos(math.radians(t_2))*math.sin(math.radians(t_2))\n",
-      "\n",
-      "#Result\n",
-      "print \"The normal and shear stresses on the plane ab and cd are\", round((T_1/1E+6),2), round((s_1/1E+6),2), \"MPa respecively\" \n",
-      "print \"respecively The normal and shear stresses on the plane ad and bc are\", round((T_2/1E+6),2), round((s_2/1E+6),2), \"MPa respecively\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The normal and shear stresses on the plane ab and cd are 28.73 -61.6 MPa respecively\n",
-        "respecively The normal and shear stresses on the plane ad and bc are -28.73 -13.4 MPa respecively\n"
-       ]
-      }
-     ],
-     "prompt_number": 4
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.11, page no. 114"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "Calculate the vertical displacement of the joint\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "# Value of s_x based on allowable stresses on glued joint\n",
-      "\n",
-      "#initialisation\n",
-      "s_t = -750.0                                  #psi\n",
-      "t = -50.0                                     #degree\n",
-      "T_t = -500.0                                  #psi\n",
-      "\n",
-      "sg_x_1 = s_t/(math.cos(math.radians(t))**2)\n",
-      "sg_x_2 = -T_t/(math.cos(math.radians(t))*math.sin(math.radians(t)))\n",
-      "\n",
-      "# Value of s_x based on allowable stresses on plastic\n",
-      "\n",
-      "sp_x_1 = -1100.0                              #psi\n",
-      "T_t_p = 600.0                                  #psi\n",
-      "t_p = 45.0                                    #degree\n",
-      "sp_x_2 = -T_t_p/(math.cos(math.radians(t_p))*math.sin(math.radians(t_p)))\n",
-      "\n",
-      "# Minimum width of bar\n",
-      "\n",
-      "P = 8000.0                                    #lb\n",
-      "A = P/sg_x_2\n",
-      "b_min = math.sqrt(abs(A))                        #inch\n",
-      "print \"The minimum width of the bar is\", round(b_min,2), \"inch\"\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The minimum width of the bar is 2.81 inch\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.15, page no. 126"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "Comparison of energy-absorbing capacity with different type of bolts\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "#Bolt with reduced shank diameter\n",
-      "\n",
-      "#initialisation\n",
-      "g = 1.50                     # inch\n",
-      "d = 0.5                      #inch\n",
-      "t = 0.25                     #inch\n",
-      "d_r = 0.406                  #inch\n",
-      "L = 13.5                     #inch\n",
-      "\n",
-      "#calculation\n",
-      "ratio = ((g*(d**2))/(((g-t)*(d_r**2))+(t*(d**2))))              #U2/U1\n",
-      "\n",
-      "print \"The energy absorbing capacity of the bolts with reduced shank diameter\", round(ratio,2)\n",
-      "ratio_1 = ( (((L-t)*(d_r**2))+(t*(d**2))) / ((2*(g-t)*(d_r**2))+2*(t*(d**2))) )         #U3/2U1\n",
-      "print \"The energy absorbing capacity of the long bolts\", round(ratio_1,2)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The energy absorbing capacity of the bolts with reduced shank diameter 1.4\n",
-        "The energy absorbing capacity of the long bolts 4.18\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "    Example 2.16, page no. 133"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "Determine the maximum elongation and tensile stress\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "# Maximum elongation\n",
-      "M = 20                      #kg\n",
-      "g = 9.81                    #m/s^2\n",
-      "L = 2                       #meter\n",
-      "E = 210e9                   #210Gpa\n",
-      "h = 0.15                    #meter\n",
-      "diameter = 0.015            #milimeter\n",
-      "\n",
-      "#Calculations & Result\n",
-      "A = (math.pi/4)*(diameter**2)               #area\n",
-      "D_st = ((M*g*L)/(E*A)) \n",
-      "D_max = D_st*(1+(1+(2*h/D_st))**0.5) \n",
-      "D_max_1 = math.sqrt(2*h*D_st)                # another approach to find D_max\n",
-      "i = D_max / D_st                             # Impact factor\n",
-      "print \"Maximum elongation is\",round((D_max/1E-3),2), \"mm\"  # Maximum tensile stress\n",
-      "s_max = (E*D_max)/L                          #Maximum tensile stress\n",
-      "s_st = (M*g)/A                               #static stress\n",
-      "i_1 = s_max / s_st                           #Impact factor \n",
-      "print \"Maximum tensile stress is \", round((s_max/1E+6),2), \"MPa\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum elongation is 1.79 mm\n",
-        "Maximum tensile stress is  188.13 MPa\n"
-       ]
-      }
-     ],
-     "prompt_number": 7
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.18, page no. 148"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "determine displacement at the lower end of bar in various conditions\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "\n",
-      "#initialisation\n",
-      "P1 = 108000.0                 #Newton\n",
-      "P2 = 27000.0                  #Newton\n",
-      "L = 2.2                     #meter\n",
-      "A = 480.0                     #mm^2\n",
-      "\n",
-      "\n",
-      "#calculations\n",
-      "\n",
-      "# Displacement due to load P1 acting alone\n",
-      "s = (P1/A)                      #stress in MPa\n",
-      "e = (s/70000) + (1/628.2)*((s/260)**10)         #strain\n",
-      "D_b = e*L*1e3                                   #elongation in mm\n",
-      "print \"elongation when only P1 load acting is = \", round(D_b,2), \" mm\"\n",
-      "\n",
-      "# Displacement due to load P2 acting alone\n",
-      "s_1 = (P2/A) #stress in MPa\n",
-      "e_1 = (s_1/70000) + (1/628.2)*((s_1/260)**10) #strain\n",
-      "D_b_1 = e_1*(L/2)*1e3 #elongation in mm (no elongation in lower half)\n",
-      "print \"elongation when only P2 load acting is = \", round(D_b_1,2), \" mm\"\n",
-      "\n",
-      "# Displacement due to both load acting simonmath.taneously\n",
-      "#upper half\n",
-      "s_2 = (P1/A) #stress in MPa\n",
-      "e_2 = (s_2/70000) + (1/628.2)*((s_2/260)**10) #strain\n",
-      "\n",
-      "#lower half\n",
-      "s_3 = (P1+P2)/A #stress in MPa\n",
-      "e_3 = (s_3/70000) + (1/628.2)*((s_3/260)**10) #strain\n",
-      "D_b_2 = ((e_2*L)/2 + (e_3*L)/2) * 1e3 # elongation in mm\n",
-      "print \"elongation when P1 and P2 both loads are acting is = \", round(D_b_2,2), \" mm\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "elongation when only P1 load acting is =  7.9  mm\n",
-        "elongation when only P2 load acting is =  0.88  mm\n",
-        "elongation when P1 and P2 both loads are acting is =  12.21  mm\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Testing_the_interface/chapter2_3.ipynb b/Testing_the_interface/chapter2_3.ipynb
deleted file mode 100755
index c4e1ad0f..00000000
--- a/Testing_the_interface/chapter2_3.ipynb
+++ /dev/null
@@ -1,501 +0,0 @@
-{
- "metadata": {
-  "name": ""
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 2: Axially Loaded Members"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.1, page no. 72"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculating the number of revolutions for the nut\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "\n",
-      "W = 2.0                       #lb\n",
-      "b = 10.5                   #inch\n",
-      "c = 6.4                    #inch\n",
-      "k = 4.2                    #inch\n",
-      "p = 1.0/16.0                   #inch\n",
-      "\n",
-      "#calculation\n",
-      "\n",
-      "n = (W*b)/(c*k*p)          #inch\n",
-      "\n",
-      "#result\n",
-      "\n",
-      "print \" No. of revolution required = \", n, \"revolutions\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " No. of revolution required =  12.5 revolutions\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.2, page no. 74"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "finding maximum allowable load\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "import numpy\n",
-      "\n",
-      "#initialisation\n",
-      "\n",
-      "Fce_ = 2.0                    #dummy variable\n",
-      "Fbd_ = 3.0                    #dummy variable    \n",
-      "Lbd = 480.0                   #mm\n",
-      "Lce = 600.0                  #mm\n",
-      "E = 205e6                   #205Gpa\n",
-      "Abd = 1020.0                  #mm\n",
-      "Ace = 520.0                   #mm\n",
-      "\n",
-      "#calculation\n",
-      "Dbd_ = (Fbd_*Lbd)/(E*Abd)   #dummy variable\n",
-      "Dce_ = (Fce_*Lce)/(E*Ace)   #dummy variable\n",
-      "Da = 1 #limiting value\n",
-      "P = ((((450+225)/225)*(Dbd_ + Dce_) - Dce_ )**(-1)) * Da  \n",
-      "Fce = 2*P # Real value in newton\n",
-      "Fbd = 3*P #real value in newton\n",
-      "Dbd = (Fbd*Lbd)/(E*Abd) #print lacement in mm\n",
-      "Dce = (Fce*Lce)/(E*Ace) # print lacement in mm\n",
-      "a = numpy.degrees(numpy.arctan(((Da+Dce)/675)))  #alpha in degree\n",
-      "\n",
-      "#result\n",
-      "print \"alpha = \", round(a,2), \"degree\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "alpha =  0.11 degree\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.3, page no. 80"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculation if vertical displacement\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "P1 = 2100.0                       #lb\n",
-      "P2 = 5600.0                       #lb\n",
-      "b = 25.0                          #inch\n",
-      "a = 28.0                          #inch\n",
-      "A1 = 0.25                       #inch^2\n",
-      "A2 = 0.15                       #inch^2\n",
-      "L1 = 20.0                         #inch\n",
-      "L2 = 34.8                       #inch\n",
-      "E = 29e6                        #29Gpa\n",
-      "\n",
-      "#Calculations\n",
-      "P3 = (P2*b)/a \n",
-      "Ra = P3-P1\n",
-      "N1 = -Ra \n",
-      "N2 = P1 \n",
-      "D = ((N1*L1)/(E*A1)) + ((N2*L2)/(E*A2))     #print lacement\n",
-      "\n",
-      "#Result\n",
-      "print  \"Downward print lacement is = \", D, \"inch\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Downward print lacement is =  0.0088 inch\n"
-       ]
-      }
-     ],
-     "prompt_number": 4
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.6, page no. 90"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "obtaing formula and calculating allowable load\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#Numerical calculation of allowable load\n",
-      "\n",
-      "d1 = 4.0                      #mm\n",
-      "d2 = 3.0                      #mm\n",
-      "A1 = (math.pi*(d1**2))/4    #area\n",
-      "A2 = (math.pi*(d2**2))/4    #area\n",
-      "L1 = 0.4                    #meter\n",
-      "L2 = 0.3                    #meter\n",
-      "E1 = 72e9                   #Gpa\n",
-      "E2 = 45e9                   #Gpa\n",
-      "f1 = L1/(E1*A1) * 1e6       # To cpmpensate for the mm**2\n",
-      "f2 = L2/(E2*A2) * 1e6 \n",
-      "s1 = 200e6                  #stress\n",
-      "s2 = 175e6                  #stress\n",
-      "\n",
-      "#Calculations\n",
-      "P1 = ( (s1*A1*(4*f1 + f2))/(3*f2) ) * 1e-6      # To cpmpensate for the mm**2\n",
-      "P2 = ( (s2*A2*(4*f1 + f2))/(6*f1) ) * 1e-6 \n",
-      "\n",
-      "#Result\n",
-      "print \"Newton Minimum allowable stress aomong the two P1 and P2 is smaller one, therefore MAS = \", P2"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Newton Minimum allowable stress aomong the two P1 and P2 is smaller one, therefore MAS =  1264.49104307\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.10, page no. 113"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculate stress acting on inclined section &\n",
-      "the complete state of stress\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "P = 90000.0                   #newton\n",
-      "A = 1200e-6                   # meter^2\n",
-      "s_x = -P/A                    #stress\n",
-      "t_1 = 25.0                    #for the stresses on ab and cd plane\n",
-      "\n",
-      "#Calculations\n",
-      "s_1 = s_x*(math.cos(math.radians(t_1))**2)\n",
-      "T_1 = -s_x*math.cos(math.radians(t_1))*math.sin(math.radians(t_1))\n",
-      "t_2 = -65.0                   #for the stresses on ad and bc plane\n",
-      "s_2 = s_x*(math.cos(math.radians(t_2))**2)\n",
-      "T_2 = -s_x*math.cos(math.radians(t_2))*math.sin(math.radians(t_2))\n",
-      "\n",
-      "#Result\n",
-      "print \"The normal and shear stresses on the plane ab and cd are\", round((T_1/1E+6),2), round((s_1/1E+6),2), \"MPa respecively\" \n",
-      "print \"respecively The normal and shear stresses on the plane ad and bc are\", round((T_2/1E+6),2), round((s_2/1E+6),2), \"MPa respecively\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The normal and shear stresses on the plane ab and cd are 28.73 -61.6 MPa respecively\n",
-        "respecively The normal and shear stresses on the plane ad and bc are -28.73 -13.4 MPa respecively\n"
-       ]
-      }
-     ],
-     "prompt_number": 4
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.11, page no. 114"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "Calculate the vertical displacement of the joint\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "# Value of s_x based on allowable stresses on glued joint\n",
-      "\n",
-      "#initialisation\n",
-      "s_t = -750.0                                  #psi\n",
-      "t = -50.0                                     #degree\n",
-      "T_t = -500.0                                  #psi\n",
-      "\n",
-      "sg_x_1 = s_t/(math.cos(math.radians(t))**2)\n",
-      "sg_x_2 = -T_t/(math.cos(math.radians(t))*math.sin(math.radians(t)))\n",
-      "\n",
-      "# Value of s_x based on allowable stresses on plastic\n",
-      "\n",
-      "sp_x_1 = -1100.0                              #psi\n",
-      "T_t_p = 600.0                                  #psi\n",
-      "t_p = 45.0                                    #degree\n",
-      "sp_x_2 = -T_t_p/(math.cos(math.radians(t_p))*math.sin(math.radians(t_p)))\n",
-      "\n",
-      "# Minimum width of bar\n",
-      "\n",
-      "P = 8000.0                                    #lb\n",
-      "A = P/sg_x_2\n",
-      "b_min = math.sqrt(abs(A))                        #inch\n",
-      "print \"The minimum width of the bar is\", round(b_min,2), \"inch\"\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The minimum width of the bar is 2.81 inch\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.15, page no. 126"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "Comparison of energy-absorbing capacity with different type of bolts\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "#Bolt with reduced shank diameter\n",
-      "\n",
-      "#initialisation\n",
-      "g = 1.50                     # inch\n",
-      "d = 0.5                      #inch\n",
-      "t = 0.25                     #inch\n",
-      "d_r = 0.406                  #inch\n",
-      "L = 13.5                     #inch\n",
-      "\n",
-      "#calculation\n",
-      "ratio = ((g*(d**2))/(((g-t)*(d_r**2))+(t*(d**2))))              #U2/U1\n",
-      "\n",
-      "print \"The energy absorbing capacity of the bolts with reduced shank diameter\", round(ratio,2)\n",
-      "ratio_1 = ( (((L-t)*(d_r**2))+(t*(d**2))) / ((2*(g-t)*(d_r**2))+2*(t*(d**2))) )         #U3/2U1\n",
-      "print \"The energy absorbing capacity of the long bolts\", round(ratio_1,2)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The energy absorbing capacity of the bolts with reduced shank diameter 1.4\n",
-        "The energy absorbing capacity of the long bolts 4.18\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "    Example 2.16, page no. 133"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "Determine the maximum elongation and tensile stress\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "# Maximum elongation\n",
-      "M = 20                      #kg\n",
-      "g = 9.81                    #m/s^2\n",
-      "L = 2                       #meter\n",
-      "E = 210e9                   #210Gpa\n",
-      "h = 0.15                    #meter\n",
-      "diameter = 0.015            #milimeter\n",
-      "\n",
-      "#Calculations & Result\n",
-      "A = (math.pi/4)*(diameter**2)               #area\n",
-      "D_st = ((M*g*L)/(E*A)) \n",
-      "D_max = D_st*(1+(1+(2*h/D_st))**0.5) \n",
-      "D_max_1 = math.sqrt(2*h*D_st)                # another approach to find D_max\n",
-      "i = D_max / D_st                             # Impact factor\n",
-      "print \"Maximum elongation is\",round((D_max/1E-3),2), \"mm\"  # Maximum tensile stress\n",
-      "s_max = (E*D_max)/L                          #Maximum tensile stress\n",
-      "s_st = (M*g)/A                               #static stress\n",
-      "i_1 = s_max / s_st                           #Impact factor \n",
-      "print \"Maximum tensile stress is \", round((s_max/1E+6),2), \"MPa\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum elongation is 1.79 mm\n",
-        "Maximum tensile stress is  188.13 MPa\n"
-       ]
-      }
-     ],
-     "prompt_number": 7
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.18, page no. 148"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "determine displacement at the lower end of bar in various conditions\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "\n",
-      "#initialisation\n",
-      "P1 = 108000.0                 #Newton\n",
-      "P2 = 27000.0                  #Newton\n",
-      "L = 2.2                     #meter\n",
-      "A = 480.0                     #mm^2\n",
-      "\n",
-      "\n",
-      "#calculations\n",
-      "\n",
-      "# Displacement due to load P1 acting alone\n",
-      "s = (P1/A)                      #stress in MPa\n",
-      "e = (s/70000) + (1/628.2)*((s/260)**10)         #strain\n",
-      "D_b = e*L*1e3                                   #elongation in mm\n",
-      "print \"elongation when only P1 load acting is = \", round(D_b,2), \" mm\"\n",
-      "\n",
-      "# Displacement due to load P2 acting alone\n",
-      "s_1 = (P2/A) #stress in MPa\n",
-      "e_1 = (s_1/70000) + (1/628.2)*((s_1/260)**10) #strain\n",
-      "D_b_1 = e_1*(L/2)*1e3 #elongation in mm (no elongation in lower half)\n",
-      "print \"elongation when only P2 load acting is = \", round(D_b_1,2), \" mm\"\n",
-      "\n",
-      "# Displacement due to both load acting simonmath.taneously\n",
-      "#upper half\n",
-      "s_2 = (P1/A) #stress in MPa\n",
-      "e_2 = (s_2/70000) + (1/628.2)*((s_2/260)**10) #strain\n",
-      "\n",
-      "#lower half\n",
-      "s_3 = (P1+P2)/A #stress in MPa\n",
-      "e_3 = (s_3/70000) + (1/628.2)*((s_3/260)**10) #strain\n",
-      "D_b_2 = ((e_2*L)/2 + (e_3*L)/2) * 1e3 # elongation in mm\n",
-      "print \"elongation when P1 and P2 both loads are acting is = \", round(D_b_2,2), \" mm\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "elongation when only P1 load acting is =  7.9  mm\n",
-        "elongation when only P2 load acting is =  0.88  mm\n",
-        "elongation when P1 and P2 both loads are acting is =  12.21  mm\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Testing_the_interface/chapter3.ipynb b/Testing_the_interface/chapter3.ipynb
deleted file mode 100755
index 8a396811..00000000
--- a/Testing_the_interface/chapter3.ipynb
+++ /dev/null
@@ -1,495 +0,0 @@
-{
- "metadata": {
-  "name": ""
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 3: Torsion"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.1, page no. 196"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculating maximum shear stress & torque\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "d = 1.5                         # diameter of bar in inch\n",
-      "L = 54.0                        # Length of bar in inch\n",
-      "G = 11.5e06                     # modulus of elasticity in psi \n",
-      "\n",
-      "#calculation\n",
-      "\n",
-      "# Part (a)\n",
-      "T = 250.0                           # torque\n",
-      "t_max = (16*T*12)/(math.pi*(d**3))  # maximum shear stress in bar\n",
-      "Ip = (math.pi*(d**4))/32            # polar miment of inertia \n",
-      "f = (T*12*L)/(G*Ip)                 # twist in radian\n",
-      "f_ = (f*180)/math.pi                # twist in degree\n",
-      "print \"Maximum shear stress in the bar is \", round(t_max), \" psi\"\n",
-      "print \"Angle of twist is\", round(f_,2), \" degree\"\n",
-      "\n",
-      "#Part (b)\n",
-      "t_allow = 6000                          # allowable shear stress\n",
-      "T1 = (math.pi*(d**3)*t_allow)/16        #allowable permissible torque in lb-in\n",
-      "T1_ = T1*0.0831658                      #allowable permissible torque in lb-ft\n",
-      "f_allow = (2.5*math.pi)/180             # allowable twist in radian\n",
-      "T2 = (G*Ip*f_allow)/L                   # allowable stress via a another method\n",
-      "T2_ = T2*0.0831658                      #allowable permissible torque in lb-ft\n",
-      "T_max = min(T1_,T2_)                    # minimum of the two\n",
-      "print \"Maximum permissible torque in the bar is\", round(T_max), \" lb-ft\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum shear stress in the bar is  4527.0  psi\n",
-        "Angle of twist is 1.62  degree\n",
-        "Maximum permissible torque in the bar is 331.0  lb-ft\n"
-       ]
-      }
-     ],
-     "prompt_number": 2
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.2, page no. 197"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "Calculation of required diameter, outer diameter & ratio of diameteres\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "T = 1200.0                                # allowable torque in N-m\n",
-      "t = 40e06                               # allowable shear stress in Pa\n",
-      "f = (0.75*math.pi)/180.0                # allowable rate of twist in rad/meter\n",
-      "G = 78e09                               # modulus of elasticity\n",
-      "\n",
-      "#calculation\n",
-      "\n",
-      "# Part (a) : Solid shaft\n",
-      "d0 = ((16.0*T)/(math.pi*t))**(1.0/3.0)\n",
-      "Ip = T/(G*f)                            # polar moment of inertia\n",
-      "d01 = ((32.0*Ip)/(math.pi))**(1.0/4.0)        # from rate of twist definition\n",
-      "print \"The required diameter of the solid shaft is \", round(d0,5), \"m\"\n",
-      "\n",
-      "# Part (b) : hollow shaft\n",
-      "d2 = (T/(0.1159*t))**(1.0/3.0)              # Diamater of hollow shaft in meter\n",
-      "d2_ = (T/(0.05796*G*f))**(1.0/4.0)          # Another value of d2 by definition of theta(allow), f = T/(G*Ip)\n",
-      "d1 = 0.8*d2_                                # because rate of twist governs the design\n",
-      "print \"The required diameter of the hollow shaft is \", round(d2,5), \"m\"\n",
-      "\n",
-      "# Part (c) : Ratio of diameter and weight\n",
-      "r1 = d2_/d01                            # diameter ratio\n",
-      "r2 = ((d2_**2.0)-(d1**2.0))/(d01**2.0)        # Weight Ratio\n",
-      "print \"Ratio of the diameter of the hollow and solid shaft is\", round(r1,2)\n",
-      "print \"Ratio of the weight of the hollow and solid shaft is\", round(r2,2)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The required diameter of the solid shaft is  0.05346 m\n",
-        "The required diameter of the hollow shaft is  0.06373 m\n",
-        "Ratio of the diameter of the hollow and solid shaft is 1.14\n",
-        "Ratio of the weight of the hollow and solid shaft is 0.47\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.4, page no. 205"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "determining maximum shear stress in various parts of the shaft\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "d = 0.03                                # diameter of the shaft in meter\n",
-      "T2 = 450.0                                # Torque in N-m\n",
-      "T1 = 275.0  \n",
-      "T3 = 175.0  \n",
-      "Lbc = 0.5                               # Length of shaft in meter\n",
-      "Lcd = 0.4                               # Length of shaft in meter\n",
-      "G = 80e09                               # Modulus of elasticity\n",
-      "\n",
-      "#calculation\n",
-      "Tcd = T2-T1                             # torque in segment CD\n",
-      "Tbc = -T1                               # torque in segment BC\n",
-      "tcd = (16.0*Tcd)/(math.pi*(d**3))         # shear stress in cd segment\n",
-      "\n",
-      "print \"Shear stress in segment cd is\", round(tcd/1000000,1), \" MPa\"\n",
-      "tbc = (16.0*Tbc)/(math.pi*(d**3))         # shear stress in bc segment\n",
-      "\n",
-      "#answer given in the textbook for tbc is wrong\n",
-      "print \"Shear stress in segment bc is\", round(tbc/1000000,1), \" MPa\"\n",
-      "Ip = (math.pi/32)*(d**4)                # Polar monent of inertia\n",
-      "fbc = (Tbc*Lbc)/(G*Ip)                  # angle of twist in radian\n",
-      "fcd = (Tcd*Lcd)/(G*Ip)                  # angle of twist in radian\n",
-      "fbd = fbc + fcd                         # angle of twist in radian\n",
-      "print \"Angles of twist in section BD\", round(fbd,3), \" radian\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Shear stress in segment cd is 33.0  MPa\n",
-        "Shear stress in segment bc is -51.9  MPa\n",
-        "Angles of twist in section BD -0.011  radian\n"
-       ]
-      }
-     ],
-     "prompt_number": 6
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.6, page no. 214"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "Calculate maximum shear, tensile & compressive stress in the tube.\n",
-      "Also, calculate coressponding strains in the tube\n",
-      "\"\"\"\n",
-      "\n",
-      "import math\n",
-      "\n",
-      "#initialisation \n",
-      "d1 = 0.06                             # Inner diameter in meter\n",
-      "d2 = 0.08                             # Outer diameter in meter\n",
-      "r = d2/2.0                            # Outer radius\n",
-      "G = 27e09                             # Modulus of elasticity\n",
-      "T = 4000.0                            # Torque in N-m\n",
-      "\n",
-      "#calculation\n",
-      "Ip = (math.pi/32)*((d2**4)-(d1**4))         # Polar moment of inertia\n",
-      "t_max = (T*r)/Ip                            # maximum shear stress\n",
-      "print \"Maximum shear stress in tube is \", t_max, \" Pa\"\n",
-      "s_t = t_max                                 # Maximum tensile stress\n",
-      "print \"Maximum tensile stress in tube is \", s_t, \" Pa\"\n",
-      "s_c = -(t_max)                              # Maximum compressive stress\n",
-      "print \"Maximum compressive stress in tube is \", s_c, \" Pa\"\n",
-      "g_max = t_max / G                           # Maximum shear strain in radian\n",
-      "print \"Maximum shear strain in tube is \", round(g_max,4), \" radian\"\n",
-      "e_t = g_max/2.0                               # Maximum tensile strain in radian\n",
-      "print \"radian\",e_t,\"Maximum tensile strain in tube is \", round(e_t,4), \" radian\"\n",
-      "e_c = -g_max/2.0                              # Maximum compressive strain in radian\n",
-      "print \"Maximum compressive strain in tube is \", round(e_c,4), \" radian\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum shear stress in tube is  58205236.3308  Pa\n",
-        "Maximum tensile stress in tube is  58205236.3308  Pa\n",
-        "Maximum compressive stress in tube is  -58205236.3308  Pa\n",
-        "Maximum shear strain in tube is  0.0022  radian\n",
-        "radian 0.00107787474687 Maximum tensile strain in tube is  0.0011  radian\n",
-        "Maximum compressive strain in tube is  -0.0011  radian\n"
-       ]
-      }
-     ],
-     "prompt_number": 7
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.7, page no. 219"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "Required diameters of the shaft at various rpm\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "H = 40.0                          # Power in hp\n",
-      "s = 6000.0                        # allowable shear stress in steel in psi\n",
-      "\n",
-      "#calculation\n",
-      "# Part (a)\n",
-      "n = 500.0                                     # rpm\n",
-      "T = ((33000.0*H)/(2*math.pi*n))*(5042.0/420.0)    # Torque in lb-in\n",
-      "d = ((16.0*T)/(math.pi*s))**(1.0/3.0)             # diameter in inch\n",
-      "print \"Diameter of the shaft at 500 rpm\", round(d,2), \" inch\"\n",
-      "\n",
-      "# Part (b)\n",
-      "n1 = 3000.0                                    # rpm\n",
-      "T1 = ((33000.0*H)/(2*math.pi*n1))*(5042.0/420.0)   # Torque in lb-in\n",
-      "d1 = ((16*T1)/(math.pi*s))**(1.0/3.0)            # diameter in inch\n",
-      "print \"Diameter of the shaft at 3000 rpm\", round(d1,2), \" inch\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Diameter of the shaft at 500 rpm 1.62  inch\n",
-        "Diameter of the shaft at 3000 rpm 0.89  inch\n"
-       ]
-      }
-     ],
-     "prompt_number": 8
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.8, page no. 221"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "Find the maximum shear stress & angle of twist in the shaft\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "\n",
-      "d = 0.05                        # diameter of the shaft\n",
-      "Lab = 1.0                         # Length of shaft ab in meter\n",
-      "Lbc = 1.2                       # Length of shaft bc in meter\n",
-      "Pa = 50000.0                      # Power in Watt at A\n",
-      "Pb = 35000.0                      # Power in Watt at B\n",
-      "Ip = (math.pi/32)*(d**4)        # Polar moment of inertia\n",
-      "Pc = 15000.0                      # Power in Watt at C\n",
-      "G = 80e09                       # Modulus of elasticity\n",
-      "f = 10.0                          # frequency in Hz \n",
-      "\n",
-      "#Calculations\n",
-      "Ta = Pa/(2*math.pi*f)           # Torque in N-m at A\n",
-      "Tb = Pb/(2*math.pi*f)           # Torque in N-m at B\n",
-      "Tc = Pc/(2*math.pi*f)           # Torque in N-m at B\n",
-      "Tab = Ta                        # Torque in N-m in shaft ab\n",
-      "Tbc = Tc                        # Torque in N-m in shaft bc\n",
-      "tab = (16*Tab)/(math.pi*(d**3))         # shear stress in ab segment\n",
-      "fab = (Tab*Lab)/(G*Ip)                  # angle of twist in radian\n",
-      "tbc = (16*Tbc)/(math.pi*(d**3))         # shear stress in ab segment\n",
-      "fbc = (Tbc*Lbc)/(G*Ip)                  # angle of twist in radian\n",
-      "fac = (fab+fbc)*(180.0/math.pi)           # angle of twist in degree in segment ac\n",
-      "tmax = Tab                              # Maximum shear stress\n",
-      "\n",
-      "#Result\n",
-      "print \"The maximum shear stress tmax in the shaft\", round(tmax), \" Nm\"\n",
-      "print \"Angle of twist in segment AC\", round(fac,2), \" degree\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The maximum shear stress tmax in the shaft 796.0  Nm\n",
-        "Angle of twist in segment AC 1.26  degree\n"
-       ]
-      }
-     ],
-     "prompt_number": 9
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.10, page no. 230"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "for various loading cases, obtain formulae and calculate strain energy\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "Ta = 100.0                          # Torque in N-m at A\n",
-      "Tb = 150.0                          # Torque in N-m at B\n",
-      "L = 1.6                             # Length of shaft in meter\n",
-      "G = 80e09                           # Modulus of elasticity\n",
-      "Ip = 79.52e-09                      # polar moment of inertia in m4\n",
-      "\n",
-      "#calculation\n",
-      "\n",
-      "Ua = ((Ta**2)*L)/(2*G*Ip)           # Strain energy at A\n",
-      "print \"Torque acting at free end\", round(Ua,2), \" joule\"\n",
-      "Ub = ((Tb**2)*L)/(4*G*Ip)           # Strain energy at B\n",
-      "print \"Torque acting at mid point\", round(Ub,2), \" joule\"\n",
-      "a = (Ta*Tb*L)/(2*G*Ip)              # dummy variabble\n",
-      "Uc = Ua+a+Ub                        # Strain energy at C\n",
-      "print \"Total torque\", round(Uc,2), \"joule\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Torque acting at free end 1.26  joule\n",
-        "Torque acting at mid point 1.41  joule\n",
-        "Total torque 4.56 joule\n"
-       ]
-      }
-     ],
-     "prompt_number": 7
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.11, page no. 231"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculate the strain energy for hollow shaft\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "t = 480.0                             # Torque of consmath.tant intensity\n",
-      "L = 144.0                             # Length of bar\n",
-      "G = 11.5e06                           # Modulus of elasticity in Psi\n",
-      "Ip = 17.18                            # Polar moment of inertia\n",
-      "\n",
-      "#Calculation\n",
-      "U = ((t**2)*(L**3))/(G*Ip*6)          # strain energy in in-lb\n",
-      "\n",
-      "#Result\n",
-      "print \"The strain energy for the hollow shaft is\", round(U), \"in-lb\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The strain energy for the hollow shaft is 580.0 in-lb\n"
-       ]
-      }
-     ],
-     "prompt_number": 11
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "example 3.14, page no. 242"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "Ratio of Shear stress and angle of twist for circular & square tube\n",
-      "\"\"\"\n",
-      "import math\n",
-      "\n",
-      "r_s = (math.pi/4)              #Ratio of shear stress\n",
-      "print \"Ratio of shear stress is \", round(r_s,2)\n",
-      "r_t = (math.pi**2/16)          #Ratio of angle of twit\n",
-      "print \"Ratio of angle of twist is \", round(r_t, 2)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Ratio of shear stress is  0.79\n",
-        "Ratio of angle of twist is  0.62\n"
-       ]
-      }
-     ],
-     "prompt_number": 4
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Testing_the_interface/chapter3_1.ipynb b/Testing_the_interface/chapter3_1.ipynb
deleted file mode 100755
index 8a396811..00000000
--- a/Testing_the_interface/chapter3_1.ipynb
+++ /dev/null
@@ -1,495 +0,0 @@
-{
- "metadata": {
-  "name": ""
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 3: Torsion"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.1, page no. 196"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculating maximum shear stress & torque\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "d = 1.5                         # diameter of bar in inch\n",
-      "L = 54.0                        # Length of bar in inch\n",
-      "G = 11.5e06                     # modulus of elasticity in psi \n",
-      "\n",
-      "#calculation\n",
-      "\n",
-      "# Part (a)\n",
-      "T = 250.0                           # torque\n",
-      "t_max = (16*T*12)/(math.pi*(d**3))  # maximum shear stress in bar\n",
-      "Ip = (math.pi*(d**4))/32            # polar miment of inertia \n",
-      "f = (T*12*L)/(G*Ip)                 # twist in radian\n",
-      "f_ = (f*180)/math.pi                # twist in degree\n",
-      "print \"Maximum shear stress in the bar is \", round(t_max), \" psi\"\n",
-      "print \"Angle of twist is\", round(f_,2), \" degree\"\n",
-      "\n",
-      "#Part (b)\n",
-      "t_allow = 6000                          # allowable shear stress\n",
-      "T1 = (math.pi*(d**3)*t_allow)/16        #allowable permissible torque in lb-in\n",
-      "T1_ = T1*0.0831658                      #allowable permissible torque in lb-ft\n",
-      "f_allow = (2.5*math.pi)/180             # allowable twist in radian\n",
-      "T2 = (G*Ip*f_allow)/L                   # allowable stress via a another method\n",
-      "T2_ = T2*0.0831658                      #allowable permissible torque in lb-ft\n",
-      "T_max = min(T1_,T2_)                    # minimum of the two\n",
-      "print \"Maximum permissible torque in the bar is\", round(T_max), \" lb-ft\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum shear stress in the bar is  4527.0  psi\n",
-        "Angle of twist is 1.62  degree\n",
-        "Maximum permissible torque in the bar is 331.0  lb-ft\n"
-       ]
-      }
-     ],
-     "prompt_number": 2
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.2, page no. 197"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "Calculation of required diameter, outer diameter & ratio of diameteres\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "T = 1200.0                                # allowable torque in N-m\n",
-      "t = 40e06                               # allowable shear stress in Pa\n",
-      "f = (0.75*math.pi)/180.0                # allowable rate of twist in rad/meter\n",
-      "G = 78e09                               # modulus of elasticity\n",
-      "\n",
-      "#calculation\n",
-      "\n",
-      "# Part (a) : Solid shaft\n",
-      "d0 = ((16.0*T)/(math.pi*t))**(1.0/3.0)\n",
-      "Ip = T/(G*f)                            # polar moment of inertia\n",
-      "d01 = ((32.0*Ip)/(math.pi))**(1.0/4.0)        # from rate of twist definition\n",
-      "print \"The required diameter of the solid shaft is \", round(d0,5), \"m\"\n",
-      "\n",
-      "# Part (b) : hollow shaft\n",
-      "d2 = (T/(0.1159*t))**(1.0/3.0)              # Diamater of hollow shaft in meter\n",
-      "d2_ = (T/(0.05796*G*f))**(1.0/4.0)          # Another value of d2 by definition of theta(allow), f = T/(G*Ip)\n",
-      "d1 = 0.8*d2_                                # because rate of twist governs the design\n",
-      "print \"The required diameter of the hollow shaft is \", round(d2,5), \"m\"\n",
-      "\n",
-      "# Part (c) : Ratio of diameter and weight\n",
-      "r1 = d2_/d01                            # diameter ratio\n",
-      "r2 = ((d2_**2.0)-(d1**2.0))/(d01**2.0)        # Weight Ratio\n",
-      "print \"Ratio of the diameter of the hollow and solid shaft is\", round(r1,2)\n",
-      "print \"Ratio of the weight of the hollow and solid shaft is\", round(r2,2)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The required diameter of the solid shaft is  0.05346 m\n",
-        "The required diameter of the hollow shaft is  0.06373 m\n",
-        "Ratio of the diameter of the hollow and solid shaft is 1.14\n",
-        "Ratio of the weight of the hollow and solid shaft is 0.47\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.4, page no. 205"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "determining maximum shear stress in various parts of the shaft\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "d = 0.03                                # diameter of the shaft in meter\n",
-      "T2 = 450.0                                # Torque in N-m\n",
-      "T1 = 275.0  \n",
-      "T3 = 175.0  \n",
-      "Lbc = 0.5                               # Length of shaft in meter\n",
-      "Lcd = 0.4                               # Length of shaft in meter\n",
-      "G = 80e09                               # Modulus of elasticity\n",
-      "\n",
-      "#calculation\n",
-      "Tcd = T2-T1                             # torque in segment CD\n",
-      "Tbc = -T1                               # torque in segment BC\n",
-      "tcd = (16.0*Tcd)/(math.pi*(d**3))         # shear stress in cd segment\n",
-      "\n",
-      "print \"Shear stress in segment cd is\", round(tcd/1000000,1), \" MPa\"\n",
-      "tbc = (16.0*Tbc)/(math.pi*(d**3))         # shear stress in bc segment\n",
-      "\n",
-      "#answer given in the textbook for tbc is wrong\n",
-      "print \"Shear stress in segment bc is\", round(tbc/1000000,1), \" MPa\"\n",
-      "Ip = (math.pi/32)*(d**4)                # Polar monent of inertia\n",
-      "fbc = (Tbc*Lbc)/(G*Ip)                  # angle of twist in radian\n",
-      "fcd = (Tcd*Lcd)/(G*Ip)                  # angle of twist in radian\n",
-      "fbd = fbc + fcd                         # angle of twist in radian\n",
-      "print \"Angles of twist in section BD\", round(fbd,3), \" radian\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Shear stress in segment cd is 33.0  MPa\n",
-        "Shear stress in segment bc is -51.9  MPa\n",
-        "Angles of twist in section BD -0.011  radian\n"
-       ]
-      }
-     ],
-     "prompt_number": 6
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.6, page no. 214"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "Calculate maximum shear, tensile & compressive stress in the tube.\n",
-      "Also, calculate coressponding strains in the tube\n",
-      "\"\"\"\n",
-      "\n",
-      "import math\n",
-      "\n",
-      "#initialisation \n",
-      "d1 = 0.06                             # Inner diameter in meter\n",
-      "d2 = 0.08                             # Outer diameter in meter\n",
-      "r = d2/2.0                            # Outer radius\n",
-      "G = 27e09                             # Modulus of elasticity\n",
-      "T = 4000.0                            # Torque in N-m\n",
-      "\n",
-      "#calculation\n",
-      "Ip = (math.pi/32)*((d2**4)-(d1**4))         # Polar moment of inertia\n",
-      "t_max = (T*r)/Ip                            # maximum shear stress\n",
-      "print \"Maximum shear stress in tube is \", t_max, \" Pa\"\n",
-      "s_t = t_max                                 # Maximum tensile stress\n",
-      "print \"Maximum tensile stress in tube is \", s_t, \" Pa\"\n",
-      "s_c = -(t_max)                              # Maximum compressive stress\n",
-      "print \"Maximum compressive stress in tube is \", s_c, \" Pa\"\n",
-      "g_max = t_max / G                           # Maximum shear strain in radian\n",
-      "print \"Maximum shear strain in tube is \", round(g_max,4), \" radian\"\n",
-      "e_t = g_max/2.0                               # Maximum tensile strain in radian\n",
-      "print \"radian\",e_t,\"Maximum tensile strain in tube is \", round(e_t,4), \" radian\"\n",
-      "e_c = -g_max/2.0                              # Maximum compressive strain in radian\n",
-      "print \"Maximum compressive strain in tube is \", round(e_c,4), \" radian\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum shear stress in tube is  58205236.3308  Pa\n",
-        "Maximum tensile stress in tube is  58205236.3308  Pa\n",
-        "Maximum compressive stress in tube is  -58205236.3308  Pa\n",
-        "Maximum shear strain in tube is  0.0022  radian\n",
-        "radian 0.00107787474687 Maximum tensile strain in tube is  0.0011  radian\n",
-        "Maximum compressive strain in tube is  -0.0011  radian\n"
-       ]
-      }
-     ],
-     "prompt_number": 7
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.7, page no. 219"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "Required diameters of the shaft at various rpm\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "H = 40.0                          # Power in hp\n",
-      "s = 6000.0                        # allowable shear stress in steel in psi\n",
-      "\n",
-      "#calculation\n",
-      "# Part (a)\n",
-      "n = 500.0                                     # rpm\n",
-      "T = ((33000.0*H)/(2*math.pi*n))*(5042.0/420.0)    # Torque in lb-in\n",
-      "d = ((16.0*T)/(math.pi*s))**(1.0/3.0)             # diameter in inch\n",
-      "print \"Diameter of the shaft at 500 rpm\", round(d,2), \" inch\"\n",
-      "\n",
-      "# Part (b)\n",
-      "n1 = 3000.0                                    # rpm\n",
-      "T1 = ((33000.0*H)/(2*math.pi*n1))*(5042.0/420.0)   # Torque in lb-in\n",
-      "d1 = ((16*T1)/(math.pi*s))**(1.0/3.0)            # diameter in inch\n",
-      "print \"Diameter of the shaft at 3000 rpm\", round(d1,2), \" inch\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Diameter of the shaft at 500 rpm 1.62  inch\n",
-        "Diameter of the shaft at 3000 rpm 0.89  inch\n"
-       ]
-      }
-     ],
-     "prompt_number": 8
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.8, page no. 221"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "Find the maximum shear stress & angle of twist in the shaft\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "\n",
-      "d = 0.05                        # diameter of the shaft\n",
-      "Lab = 1.0                         # Length of shaft ab in meter\n",
-      "Lbc = 1.2                       # Length of shaft bc in meter\n",
-      "Pa = 50000.0                      # Power in Watt at A\n",
-      "Pb = 35000.0                      # Power in Watt at B\n",
-      "Ip = (math.pi/32)*(d**4)        # Polar moment of inertia\n",
-      "Pc = 15000.0                      # Power in Watt at C\n",
-      "G = 80e09                       # Modulus of elasticity\n",
-      "f = 10.0                          # frequency in Hz \n",
-      "\n",
-      "#Calculations\n",
-      "Ta = Pa/(2*math.pi*f)           # Torque in N-m at A\n",
-      "Tb = Pb/(2*math.pi*f)           # Torque in N-m at B\n",
-      "Tc = Pc/(2*math.pi*f)           # Torque in N-m at B\n",
-      "Tab = Ta                        # Torque in N-m in shaft ab\n",
-      "Tbc = Tc                        # Torque in N-m in shaft bc\n",
-      "tab = (16*Tab)/(math.pi*(d**3))         # shear stress in ab segment\n",
-      "fab = (Tab*Lab)/(G*Ip)                  # angle of twist in radian\n",
-      "tbc = (16*Tbc)/(math.pi*(d**3))         # shear stress in ab segment\n",
-      "fbc = (Tbc*Lbc)/(G*Ip)                  # angle of twist in radian\n",
-      "fac = (fab+fbc)*(180.0/math.pi)           # angle of twist in degree in segment ac\n",
-      "tmax = Tab                              # Maximum shear stress\n",
-      "\n",
-      "#Result\n",
-      "print \"The maximum shear stress tmax in the shaft\", round(tmax), \" Nm\"\n",
-      "print \"Angle of twist in segment AC\", round(fac,2), \" degree\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The maximum shear stress tmax in the shaft 796.0  Nm\n",
-        "Angle of twist in segment AC 1.26  degree\n"
-       ]
-      }
-     ],
-     "prompt_number": 9
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.10, page no. 230"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "for various loading cases, obtain formulae and calculate strain energy\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "Ta = 100.0                          # Torque in N-m at A\n",
-      "Tb = 150.0                          # Torque in N-m at B\n",
-      "L = 1.6                             # Length of shaft in meter\n",
-      "G = 80e09                           # Modulus of elasticity\n",
-      "Ip = 79.52e-09                      # polar moment of inertia in m4\n",
-      "\n",
-      "#calculation\n",
-      "\n",
-      "Ua = ((Ta**2)*L)/(2*G*Ip)           # Strain energy at A\n",
-      "print \"Torque acting at free end\", round(Ua,2), \" joule\"\n",
-      "Ub = ((Tb**2)*L)/(4*G*Ip)           # Strain energy at B\n",
-      "print \"Torque acting at mid point\", round(Ub,2), \" joule\"\n",
-      "a = (Ta*Tb*L)/(2*G*Ip)              # dummy variabble\n",
-      "Uc = Ua+a+Ub                        # Strain energy at C\n",
-      "print \"Total torque\", round(Uc,2), \"joule\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Torque acting at free end 1.26  joule\n",
-        "Torque acting at mid point 1.41  joule\n",
-        "Total torque 4.56 joule\n"
-       ]
-      }
-     ],
-     "prompt_number": 7
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.11, page no. 231"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculate the strain energy for hollow shaft\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "t = 480.0                             # Torque of consmath.tant intensity\n",
-      "L = 144.0                             # Length of bar\n",
-      "G = 11.5e06                           # Modulus of elasticity in Psi\n",
-      "Ip = 17.18                            # Polar moment of inertia\n",
-      "\n",
-      "#Calculation\n",
-      "U = ((t**2)*(L**3))/(G*Ip*6)          # strain energy in in-lb\n",
-      "\n",
-      "#Result\n",
-      "print \"The strain energy for the hollow shaft is\", round(U), \"in-lb\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The strain energy for the hollow shaft is 580.0 in-lb\n"
-       ]
-      }
-     ],
-     "prompt_number": 11
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "example 3.14, page no. 242"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "Ratio of Shear stress and angle of twist for circular & square tube\n",
-      "\"\"\"\n",
-      "import math\n",
-      "\n",
-      "r_s = (math.pi/4)              #Ratio of shear stress\n",
-      "print \"Ratio of shear stress is \", round(r_s,2)\n",
-      "r_t = (math.pi**2/16)          #Ratio of angle of twit\n",
-      "print \"Ratio of angle of twist is \", round(r_t, 2)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Ratio of shear stress is  0.79\n",
-        "Ratio of angle of twist is  0.62\n"
-       ]
-      }
-     ],
-     "prompt_number": 4
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Testing_the_interface/chapter3_2.ipynb b/Testing_the_interface/chapter3_2.ipynb
deleted file mode 100755
index 8a396811..00000000
--- a/Testing_the_interface/chapter3_2.ipynb
+++ /dev/null
@@ -1,495 +0,0 @@
-{
- "metadata": {
-  "name": ""
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 3: Torsion"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.1, page no. 196"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculating maximum shear stress & torque\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "d = 1.5                         # diameter of bar in inch\n",
-      "L = 54.0                        # Length of bar in inch\n",
-      "G = 11.5e06                     # modulus of elasticity in psi \n",
-      "\n",
-      "#calculation\n",
-      "\n",
-      "# Part (a)\n",
-      "T = 250.0                           # torque\n",
-      "t_max = (16*T*12)/(math.pi*(d**3))  # maximum shear stress in bar\n",
-      "Ip = (math.pi*(d**4))/32            # polar miment of inertia \n",
-      "f = (T*12*L)/(G*Ip)                 # twist in radian\n",
-      "f_ = (f*180)/math.pi                # twist in degree\n",
-      "print \"Maximum shear stress in the bar is \", round(t_max), \" psi\"\n",
-      "print \"Angle of twist is\", round(f_,2), \" degree\"\n",
-      "\n",
-      "#Part (b)\n",
-      "t_allow = 6000                          # allowable shear stress\n",
-      "T1 = (math.pi*(d**3)*t_allow)/16        #allowable permissible torque in lb-in\n",
-      "T1_ = T1*0.0831658                      #allowable permissible torque in lb-ft\n",
-      "f_allow = (2.5*math.pi)/180             # allowable twist in radian\n",
-      "T2 = (G*Ip*f_allow)/L                   # allowable stress via a another method\n",
-      "T2_ = T2*0.0831658                      #allowable permissible torque in lb-ft\n",
-      "T_max = min(T1_,T2_)                    # minimum of the two\n",
-      "print \"Maximum permissible torque in the bar is\", round(T_max), \" lb-ft\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum shear stress in the bar is  4527.0  psi\n",
-        "Angle of twist is 1.62  degree\n",
-        "Maximum permissible torque in the bar is 331.0  lb-ft\n"
-       ]
-      }
-     ],
-     "prompt_number": 2
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.2, page no. 197"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "Calculation of required diameter, outer diameter & ratio of diameteres\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "T = 1200.0                                # allowable torque in N-m\n",
-      "t = 40e06                               # allowable shear stress in Pa\n",
-      "f = (0.75*math.pi)/180.0                # allowable rate of twist in rad/meter\n",
-      "G = 78e09                               # modulus of elasticity\n",
-      "\n",
-      "#calculation\n",
-      "\n",
-      "# Part (a) : Solid shaft\n",
-      "d0 = ((16.0*T)/(math.pi*t))**(1.0/3.0)\n",
-      "Ip = T/(G*f)                            # polar moment of inertia\n",
-      "d01 = ((32.0*Ip)/(math.pi))**(1.0/4.0)        # from rate of twist definition\n",
-      "print \"The required diameter of the solid shaft is \", round(d0,5), \"m\"\n",
-      "\n",
-      "# Part (b) : hollow shaft\n",
-      "d2 = (T/(0.1159*t))**(1.0/3.0)              # Diamater of hollow shaft in meter\n",
-      "d2_ = (T/(0.05796*G*f))**(1.0/4.0)          # Another value of d2 by definition of theta(allow), f = T/(G*Ip)\n",
-      "d1 = 0.8*d2_                                # because rate of twist governs the design\n",
-      "print \"The required diameter of the hollow shaft is \", round(d2,5), \"m\"\n",
-      "\n",
-      "# Part (c) : Ratio of diameter and weight\n",
-      "r1 = d2_/d01                            # diameter ratio\n",
-      "r2 = ((d2_**2.0)-(d1**2.0))/(d01**2.0)        # Weight Ratio\n",
-      "print \"Ratio of the diameter of the hollow and solid shaft is\", round(r1,2)\n",
-      "print \"Ratio of the weight of the hollow and solid shaft is\", round(r2,2)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The required diameter of the solid shaft is  0.05346 m\n",
-        "The required diameter of the hollow shaft is  0.06373 m\n",
-        "Ratio of the diameter of the hollow and solid shaft is 1.14\n",
-        "Ratio of the weight of the hollow and solid shaft is 0.47\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.4, page no. 205"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "determining maximum shear stress in various parts of the shaft\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "d = 0.03                                # diameter of the shaft in meter\n",
-      "T2 = 450.0                                # Torque in N-m\n",
-      "T1 = 275.0  \n",
-      "T3 = 175.0  \n",
-      "Lbc = 0.5                               # Length of shaft in meter\n",
-      "Lcd = 0.4                               # Length of shaft in meter\n",
-      "G = 80e09                               # Modulus of elasticity\n",
-      "\n",
-      "#calculation\n",
-      "Tcd = T2-T1                             # torque in segment CD\n",
-      "Tbc = -T1                               # torque in segment BC\n",
-      "tcd = (16.0*Tcd)/(math.pi*(d**3))         # shear stress in cd segment\n",
-      "\n",
-      "print \"Shear stress in segment cd is\", round(tcd/1000000,1), \" MPa\"\n",
-      "tbc = (16.0*Tbc)/(math.pi*(d**3))         # shear stress in bc segment\n",
-      "\n",
-      "#answer given in the textbook for tbc is wrong\n",
-      "print \"Shear stress in segment bc is\", round(tbc/1000000,1), \" MPa\"\n",
-      "Ip = (math.pi/32)*(d**4)                # Polar monent of inertia\n",
-      "fbc = (Tbc*Lbc)/(G*Ip)                  # angle of twist in radian\n",
-      "fcd = (Tcd*Lcd)/(G*Ip)                  # angle of twist in radian\n",
-      "fbd = fbc + fcd                         # angle of twist in radian\n",
-      "print \"Angles of twist in section BD\", round(fbd,3), \" radian\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Shear stress in segment cd is 33.0  MPa\n",
-        "Shear stress in segment bc is -51.9  MPa\n",
-        "Angles of twist in section BD -0.011  radian\n"
-       ]
-      }
-     ],
-     "prompt_number": 6
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.6, page no. 214"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "Calculate maximum shear, tensile & compressive stress in the tube.\n",
-      "Also, calculate coressponding strains in the tube\n",
-      "\"\"\"\n",
-      "\n",
-      "import math\n",
-      "\n",
-      "#initialisation \n",
-      "d1 = 0.06                             # Inner diameter in meter\n",
-      "d2 = 0.08                             # Outer diameter in meter\n",
-      "r = d2/2.0                            # Outer radius\n",
-      "G = 27e09                             # Modulus of elasticity\n",
-      "T = 4000.0                            # Torque in N-m\n",
-      "\n",
-      "#calculation\n",
-      "Ip = (math.pi/32)*((d2**4)-(d1**4))         # Polar moment of inertia\n",
-      "t_max = (T*r)/Ip                            # maximum shear stress\n",
-      "print \"Maximum shear stress in tube is \", t_max, \" Pa\"\n",
-      "s_t = t_max                                 # Maximum tensile stress\n",
-      "print \"Maximum tensile stress in tube is \", s_t, \" Pa\"\n",
-      "s_c = -(t_max)                              # Maximum compressive stress\n",
-      "print \"Maximum compressive stress in tube is \", s_c, \" Pa\"\n",
-      "g_max = t_max / G                           # Maximum shear strain in radian\n",
-      "print \"Maximum shear strain in tube is \", round(g_max,4), \" radian\"\n",
-      "e_t = g_max/2.0                               # Maximum tensile strain in radian\n",
-      "print \"radian\",e_t,\"Maximum tensile strain in tube is \", round(e_t,4), \" radian\"\n",
-      "e_c = -g_max/2.0                              # Maximum compressive strain in radian\n",
-      "print \"Maximum compressive strain in tube is \", round(e_c,4), \" radian\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum shear stress in tube is  58205236.3308  Pa\n",
-        "Maximum tensile stress in tube is  58205236.3308  Pa\n",
-        "Maximum compressive stress in tube is  -58205236.3308  Pa\n",
-        "Maximum shear strain in tube is  0.0022  radian\n",
-        "radian 0.00107787474687 Maximum tensile strain in tube is  0.0011  radian\n",
-        "Maximum compressive strain in tube is  -0.0011  radian\n"
-       ]
-      }
-     ],
-     "prompt_number": 7
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.7, page no. 219"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "Required diameters of the shaft at various rpm\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "H = 40.0                          # Power in hp\n",
-      "s = 6000.0                        # allowable shear stress in steel in psi\n",
-      "\n",
-      "#calculation\n",
-      "# Part (a)\n",
-      "n = 500.0                                     # rpm\n",
-      "T = ((33000.0*H)/(2*math.pi*n))*(5042.0/420.0)    # Torque in lb-in\n",
-      "d = ((16.0*T)/(math.pi*s))**(1.0/3.0)             # diameter in inch\n",
-      "print \"Diameter of the shaft at 500 rpm\", round(d,2), \" inch\"\n",
-      "\n",
-      "# Part (b)\n",
-      "n1 = 3000.0                                    # rpm\n",
-      "T1 = ((33000.0*H)/(2*math.pi*n1))*(5042.0/420.0)   # Torque in lb-in\n",
-      "d1 = ((16*T1)/(math.pi*s))**(1.0/3.0)            # diameter in inch\n",
-      "print \"Diameter of the shaft at 3000 rpm\", round(d1,2), \" inch\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Diameter of the shaft at 500 rpm 1.62  inch\n",
-        "Diameter of the shaft at 3000 rpm 0.89  inch\n"
-       ]
-      }
-     ],
-     "prompt_number": 8
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.8, page no. 221"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "Find the maximum shear stress & angle of twist in the shaft\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "\n",
-      "d = 0.05                        # diameter of the shaft\n",
-      "Lab = 1.0                         # Length of shaft ab in meter\n",
-      "Lbc = 1.2                       # Length of shaft bc in meter\n",
-      "Pa = 50000.0                      # Power in Watt at A\n",
-      "Pb = 35000.0                      # Power in Watt at B\n",
-      "Ip = (math.pi/32)*(d**4)        # Polar moment of inertia\n",
-      "Pc = 15000.0                      # Power in Watt at C\n",
-      "G = 80e09                       # Modulus of elasticity\n",
-      "f = 10.0                          # frequency in Hz \n",
-      "\n",
-      "#Calculations\n",
-      "Ta = Pa/(2*math.pi*f)           # Torque in N-m at A\n",
-      "Tb = Pb/(2*math.pi*f)           # Torque in N-m at B\n",
-      "Tc = Pc/(2*math.pi*f)           # Torque in N-m at B\n",
-      "Tab = Ta                        # Torque in N-m in shaft ab\n",
-      "Tbc = Tc                        # Torque in N-m in shaft bc\n",
-      "tab = (16*Tab)/(math.pi*(d**3))         # shear stress in ab segment\n",
-      "fab = (Tab*Lab)/(G*Ip)                  # angle of twist in radian\n",
-      "tbc = (16*Tbc)/(math.pi*(d**3))         # shear stress in ab segment\n",
-      "fbc = (Tbc*Lbc)/(G*Ip)                  # angle of twist in radian\n",
-      "fac = (fab+fbc)*(180.0/math.pi)           # angle of twist in degree in segment ac\n",
-      "tmax = Tab                              # Maximum shear stress\n",
-      "\n",
-      "#Result\n",
-      "print \"The maximum shear stress tmax in the shaft\", round(tmax), \" Nm\"\n",
-      "print \"Angle of twist in segment AC\", round(fac,2), \" degree\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The maximum shear stress tmax in the shaft 796.0  Nm\n",
-        "Angle of twist in segment AC 1.26  degree\n"
-       ]
-      }
-     ],
-     "prompt_number": 9
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.10, page no. 230"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "for various loading cases, obtain formulae and calculate strain energy\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "Ta = 100.0                          # Torque in N-m at A\n",
-      "Tb = 150.0                          # Torque in N-m at B\n",
-      "L = 1.6                             # Length of shaft in meter\n",
-      "G = 80e09                           # Modulus of elasticity\n",
-      "Ip = 79.52e-09                      # polar moment of inertia in m4\n",
-      "\n",
-      "#calculation\n",
-      "\n",
-      "Ua = ((Ta**2)*L)/(2*G*Ip)           # Strain energy at A\n",
-      "print \"Torque acting at free end\", round(Ua,2), \" joule\"\n",
-      "Ub = ((Tb**2)*L)/(4*G*Ip)           # Strain energy at B\n",
-      "print \"Torque acting at mid point\", round(Ub,2), \" joule\"\n",
-      "a = (Ta*Tb*L)/(2*G*Ip)              # dummy variabble\n",
-      "Uc = Ua+a+Ub                        # Strain energy at C\n",
-      "print \"Total torque\", round(Uc,2), \"joule\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Torque acting at free end 1.26  joule\n",
-        "Torque acting at mid point 1.41  joule\n",
-        "Total torque 4.56 joule\n"
-       ]
-      }
-     ],
-     "prompt_number": 7
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.11, page no. 231"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculate the strain energy for hollow shaft\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "t = 480.0                             # Torque of consmath.tant intensity\n",
-      "L = 144.0                             # Length of bar\n",
-      "G = 11.5e06                           # Modulus of elasticity in Psi\n",
-      "Ip = 17.18                            # Polar moment of inertia\n",
-      "\n",
-      "#Calculation\n",
-      "U = ((t**2)*(L**3))/(G*Ip*6)          # strain energy in in-lb\n",
-      "\n",
-      "#Result\n",
-      "print \"The strain energy for the hollow shaft is\", round(U), \"in-lb\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The strain energy for the hollow shaft is 580.0 in-lb\n"
-       ]
-      }
-     ],
-     "prompt_number": 11
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "example 3.14, page no. 242"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "Ratio of Shear stress and angle of twist for circular & square tube\n",
-      "\"\"\"\n",
-      "import math\n",
-      "\n",
-      "r_s = (math.pi/4)              #Ratio of shear stress\n",
-      "print \"Ratio of shear stress is \", round(r_s,2)\n",
-      "r_t = (math.pi**2/16)          #Ratio of angle of twit\n",
-      "print \"Ratio of angle of twist is \", round(r_t, 2)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Ratio of shear stress is  0.79\n",
-        "Ratio of angle of twist is  0.62\n"
-       ]
-      }
-     ],
-     "prompt_number": 4
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Testing_the_interface/chapter3_3.ipynb b/Testing_the_interface/chapter3_3.ipynb
deleted file mode 100755
index 8a396811..00000000
--- a/Testing_the_interface/chapter3_3.ipynb
+++ /dev/null
@@ -1,495 +0,0 @@
-{
- "metadata": {
-  "name": ""
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 3: Torsion"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.1, page no. 196"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculating maximum shear stress & torque\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "d = 1.5                         # diameter of bar in inch\n",
-      "L = 54.0                        # Length of bar in inch\n",
-      "G = 11.5e06                     # modulus of elasticity in psi \n",
-      "\n",
-      "#calculation\n",
-      "\n",
-      "# Part (a)\n",
-      "T = 250.0                           # torque\n",
-      "t_max = (16*T*12)/(math.pi*(d**3))  # maximum shear stress in bar\n",
-      "Ip = (math.pi*(d**4))/32            # polar miment of inertia \n",
-      "f = (T*12*L)/(G*Ip)                 # twist in radian\n",
-      "f_ = (f*180)/math.pi                # twist in degree\n",
-      "print \"Maximum shear stress in the bar is \", round(t_max), \" psi\"\n",
-      "print \"Angle of twist is\", round(f_,2), \" degree\"\n",
-      "\n",
-      "#Part (b)\n",
-      "t_allow = 6000                          # allowable shear stress\n",
-      "T1 = (math.pi*(d**3)*t_allow)/16        #allowable permissible torque in lb-in\n",
-      "T1_ = T1*0.0831658                      #allowable permissible torque in lb-ft\n",
-      "f_allow = (2.5*math.pi)/180             # allowable twist in radian\n",
-      "T2 = (G*Ip*f_allow)/L                   # allowable stress via a another method\n",
-      "T2_ = T2*0.0831658                      #allowable permissible torque in lb-ft\n",
-      "T_max = min(T1_,T2_)                    # minimum of the two\n",
-      "print \"Maximum permissible torque in the bar is\", round(T_max), \" lb-ft\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum shear stress in the bar is  4527.0  psi\n",
-        "Angle of twist is 1.62  degree\n",
-        "Maximum permissible torque in the bar is 331.0  lb-ft\n"
-       ]
-      }
-     ],
-     "prompt_number": 2
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.2, page no. 197"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "Calculation of required diameter, outer diameter & ratio of diameteres\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "T = 1200.0                                # allowable torque in N-m\n",
-      "t = 40e06                               # allowable shear stress in Pa\n",
-      "f = (0.75*math.pi)/180.0                # allowable rate of twist in rad/meter\n",
-      "G = 78e09                               # modulus of elasticity\n",
-      "\n",
-      "#calculation\n",
-      "\n",
-      "# Part (a) : Solid shaft\n",
-      "d0 = ((16.0*T)/(math.pi*t))**(1.0/3.0)\n",
-      "Ip = T/(G*f)                            # polar moment of inertia\n",
-      "d01 = ((32.0*Ip)/(math.pi))**(1.0/4.0)        # from rate of twist definition\n",
-      "print \"The required diameter of the solid shaft is \", round(d0,5), \"m\"\n",
-      "\n",
-      "# Part (b) : hollow shaft\n",
-      "d2 = (T/(0.1159*t))**(1.0/3.0)              # Diamater of hollow shaft in meter\n",
-      "d2_ = (T/(0.05796*G*f))**(1.0/4.0)          # Another value of d2 by definition of theta(allow), f = T/(G*Ip)\n",
-      "d1 = 0.8*d2_                                # because rate of twist governs the design\n",
-      "print \"The required diameter of the hollow shaft is \", round(d2,5), \"m\"\n",
-      "\n",
-      "# Part (c) : Ratio of diameter and weight\n",
-      "r1 = d2_/d01                            # diameter ratio\n",
-      "r2 = ((d2_**2.0)-(d1**2.0))/(d01**2.0)        # Weight Ratio\n",
-      "print \"Ratio of the diameter of the hollow and solid shaft is\", round(r1,2)\n",
-      "print \"Ratio of the weight of the hollow and solid shaft is\", round(r2,2)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The required diameter of the solid shaft is  0.05346 m\n",
-        "The required diameter of the hollow shaft is  0.06373 m\n",
-        "Ratio of the diameter of the hollow and solid shaft is 1.14\n",
-        "Ratio of the weight of the hollow and solid shaft is 0.47\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.4, page no. 205"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "determining maximum shear stress in various parts of the shaft\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "d = 0.03                                # diameter of the shaft in meter\n",
-      "T2 = 450.0                                # Torque in N-m\n",
-      "T1 = 275.0  \n",
-      "T3 = 175.0  \n",
-      "Lbc = 0.5                               # Length of shaft in meter\n",
-      "Lcd = 0.4                               # Length of shaft in meter\n",
-      "G = 80e09                               # Modulus of elasticity\n",
-      "\n",
-      "#calculation\n",
-      "Tcd = T2-T1                             # torque in segment CD\n",
-      "Tbc = -T1                               # torque in segment BC\n",
-      "tcd = (16.0*Tcd)/(math.pi*(d**3))         # shear stress in cd segment\n",
-      "\n",
-      "print \"Shear stress in segment cd is\", round(tcd/1000000,1), \" MPa\"\n",
-      "tbc = (16.0*Tbc)/(math.pi*(d**3))         # shear stress in bc segment\n",
-      "\n",
-      "#answer given in the textbook for tbc is wrong\n",
-      "print \"Shear stress in segment bc is\", round(tbc/1000000,1), \" MPa\"\n",
-      "Ip = (math.pi/32)*(d**4)                # Polar monent of inertia\n",
-      "fbc = (Tbc*Lbc)/(G*Ip)                  # angle of twist in radian\n",
-      "fcd = (Tcd*Lcd)/(G*Ip)                  # angle of twist in radian\n",
-      "fbd = fbc + fcd                         # angle of twist in radian\n",
-      "print \"Angles of twist in section BD\", round(fbd,3), \" radian\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Shear stress in segment cd is 33.0  MPa\n",
-        "Shear stress in segment bc is -51.9  MPa\n",
-        "Angles of twist in section BD -0.011  radian\n"
-       ]
-      }
-     ],
-     "prompt_number": 6
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.6, page no. 214"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "Calculate maximum shear, tensile & compressive stress in the tube.\n",
-      "Also, calculate coressponding strains in the tube\n",
-      "\"\"\"\n",
-      "\n",
-      "import math\n",
-      "\n",
-      "#initialisation \n",
-      "d1 = 0.06                             # Inner diameter in meter\n",
-      "d2 = 0.08                             # Outer diameter in meter\n",
-      "r = d2/2.0                            # Outer radius\n",
-      "G = 27e09                             # Modulus of elasticity\n",
-      "T = 4000.0                            # Torque in N-m\n",
-      "\n",
-      "#calculation\n",
-      "Ip = (math.pi/32)*((d2**4)-(d1**4))         # Polar moment of inertia\n",
-      "t_max = (T*r)/Ip                            # maximum shear stress\n",
-      "print \"Maximum shear stress in tube is \", t_max, \" Pa\"\n",
-      "s_t = t_max                                 # Maximum tensile stress\n",
-      "print \"Maximum tensile stress in tube is \", s_t, \" Pa\"\n",
-      "s_c = -(t_max)                              # Maximum compressive stress\n",
-      "print \"Maximum compressive stress in tube is \", s_c, \" Pa\"\n",
-      "g_max = t_max / G                           # Maximum shear strain in radian\n",
-      "print \"Maximum shear strain in tube is \", round(g_max,4), \" radian\"\n",
-      "e_t = g_max/2.0                               # Maximum tensile strain in radian\n",
-      "print \"radian\",e_t,\"Maximum tensile strain in tube is \", round(e_t,4), \" radian\"\n",
-      "e_c = -g_max/2.0                              # Maximum compressive strain in radian\n",
-      "print \"Maximum compressive strain in tube is \", round(e_c,4), \" radian\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum shear stress in tube is  58205236.3308  Pa\n",
-        "Maximum tensile stress in tube is  58205236.3308  Pa\n",
-        "Maximum compressive stress in tube is  -58205236.3308  Pa\n",
-        "Maximum shear strain in tube is  0.0022  radian\n",
-        "radian 0.00107787474687 Maximum tensile strain in tube is  0.0011  radian\n",
-        "Maximum compressive strain in tube is  -0.0011  radian\n"
-       ]
-      }
-     ],
-     "prompt_number": 7
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.7, page no. 219"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "Required diameters of the shaft at various rpm\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "H = 40.0                          # Power in hp\n",
-      "s = 6000.0                        # allowable shear stress in steel in psi\n",
-      "\n",
-      "#calculation\n",
-      "# Part (a)\n",
-      "n = 500.0                                     # rpm\n",
-      "T = ((33000.0*H)/(2*math.pi*n))*(5042.0/420.0)    # Torque in lb-in\n",
-      "d = ((16.0*T)/(math.pi*s))**(1.0/3.0)             # diameter in inch\n",
-      "print \"Diameter of the shaft at 500 rpm\", round(d,2), \" inch\"\n",
-      "\n",
-      "# Part (b)\n",
-      "n1 = 3000.0                                    # rpm\n",
-      "T1 = ((33000.0*H)/(2*math.pi*n1))*(5042.0/420.0)   # Torque in lb-in\n",
-      "d1 = ((16*T1)/(math.pi*s))**(1.0/3.0)            # diameter in inch\n",
-      "print \"Diameter of the shaft at 3000 rpm\", round(d1,2), \" inch\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Diameter of the shaft at 500 rpm 1.62  inch\n",
-        "Diameter of the shaft at 3000 rpm 0.89  inch\n"
-       ]
-      }
-     ],
-     "prompt_number": 8
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.8, page no. 221"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "Find the maximum shear stress & angle of twist in the shaft\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "\n",
-      "d = 0.05                        # diameter of the shaft\n",
-      "Lab = 1.0                         # Length of shaft ab in meter\n",
-      "Lbc = 1.2                       # Length of shaft bc in meter\n",
-      "Pa = 50000.0                      # Power in Watt at A\n",
-      "Pb = 35000.0                      # Power in Watt at B\n",
-      "Ip = (math.pi/32)*(d**4)        # Polar moment of inertia\n",
-      "Pc = 15000.0                      # Power in Watt at C\n",
-      "G = 80e09                       # Modulus of elasticity\n",
-      "f = 10.0                          # frequency in Hz \n",
-      "\n",
-      "#Calculations\n",
-      "Ta = Pa/(2*math.pi*f)           # Torque in N-m at A\n",
-      "Tb = Pb/(2*math.pi*f)           # Torque in N-m at B\n",
-      "Tc = Pc/(2*math.pi*f)           # Torque in N-m at B\n",
-      "Tab = Ta                        # Torque in N-m in shaft ab\n",
-      "Tbc = Tc                        # Torque in N-m in shaft bc\n",
-      "tab = (16*Tab)/(math.pi*(d**3))         # shear stress in ab segment\n",
-      "fab = (Tab*Lab)/(G*Ip)                  # angle of twist in radian\n",
-      "tbc = (16*Tbc)/(math.pi*(d**3))         # shear stress in ab segment\n",
-      "fbc = (Tbc*Lbc)/(G*Ip)                  # angle of twist in radian\n",
-      "fac = (fab+fbc)*(180.0/math.pi)           # angle of twist in degree in segment ac\n",
-      "tmax = Tab                              # Maximum shear stress\n",
-      "\n",
-      "#Result\n",
-      "print \"The maximum shear stress tmax in the shaft\", round(tmax), \" Nm\"\n",
-      "print \"Angle of twist in segment AC\", round(fac,2), \" degree\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The maximum shear stress tmax in the shaft 796.0  Nm\n",
-        "Angle of twist in segment AC 1.26  degree\n"
-       ]
-      }
-     ],
-     "prompt_number": 9
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.10, page no. 230"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "for various loading cases, obtain formulae and calculate strain energy\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "Ta = 100.0                          # Torque in N-m at A\n",
-      "Tb = 150.0                          # Torque in N-m at B\n",
-      "L = 1.6                             # Length of shaft in meter\n",
-      "G = 80e09                           # Modulus of elasticity\n",
-      "Ip = 79.52e-09                      # polar moment of inertia in m4\n",
-      "\n",
-      "#calculation\n",
-      "\n",
-      "Ua = ((Ta**2)*L)/(2*G*Ip)           # Strain energy at A\n",
-      "print \"Torque acting at free end\", round(Ua,2), \" joule\"\n",
-      "Ub = ((Tb**2)*L)/(4*G*Ip)           # Strain energy at B\n",
-      "print \"Torque acting at mid point\", round(Ub,2), \" joule\"\n",
-      "a = (Ta*Tb*L)/(2*G*Ip)              # dummy variabble\n",
-      "Uc = Ua+a+Ub                        # Strain energy at C\n",
-      "print \"Total torque\", round(Uc,2), \"joule\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Torque acting at free end 1.26  joule\n",
-        "Torque acting at mid point 1.41  joule\n",
-        "Total torque 4.56 joule\n"
-       ]
-      }
-     ],
-     "prompt_number": 7
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.11, page no. 231"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculate the strain energy for hollow shaft\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "t = 480.0                             # Torque of consmath.tant intensity\n",
-      "L = 144.0                             # Length of bar\n",
-      "G = 11.5e06                           # Modulus of elasticity in Psi\n",
-      "Ip = 17.18                            # Polar moment of inertia\n",
-      "\n",
-      "#Calculation\n",
-      "U = ((t**2)*(L**3))/(G*Ip*6)          # strain energy in in-lb\n",
-      "\n",
-      "#Result\n",
-      "print \"The strain energy for the hollow shaft is\", round(U), \"in-lb\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The strain energy for the hollow shaft is 580.0 in-lb\n"
-       ]
-      }
-     ],
-     "prompt_number": 11
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "example 3.14, page no. 242"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "Ratio of Shear stress and angle of twist for circular & square tube\n",
-      "\"\"\"\n",
-      "import math\n",
-      "\n",
-      "r_s = (math.pi/4)              #Ratio of shear stress\n",
-      "print \"Ratio of shear stress is \", round(r_s,2)\n",
-      "r_t = (math.pi**2/16)          #Ratio of angle of twit\n",
-      "print \"Ratio of angle of twist is \", round(r_t, 2)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Ratio of shear stress is  0.79\n",
-        "Ratio of angle of twist is  0.62\n"
-       ]
-      }
-     ],
-     "prompt_number": 4
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Testing_the_interface/chapter4.ipynb b/Testing_the_interface/chapter4.ipynb
deleted file mode 100755
index e9b7e3e0..00000000
--- a/Testing_the_interface/chapter4.ipynb
+++ /dev/null
@@ -1,116 +0,0 @@
-{
- "metadata": {
-  "name": ""
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 4: Shear Forces and Bending Moments"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 4.3, page no. 275"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "Finding shear force V and bending movement M at cross section D located 115 ft from left-hand behind support\n",
-      "\"\"\"\n",
-      "\n",
-      "import math\n",
-      "\n",
-      "#initialisation\n",
-      "\n",
-      "q = 0.2                     # Uniform load intensity in K/ft\n",
-      "P = 14                      # Concentrated load in k\n",
-      "Ra = 11                     # Reaction at A from wquation of equilibrium\n",
-      "Rb = 9                      # Reaction at B from wquation of equilibrium\n",
-      "\n",
-      "#calculation\n",
-      "V = 11 - 14 - (0.2*15)      # shear force in k\n",
-      "\n",
-      "print \"Shear force at section D\", V, \"k\"\n",
-      "M = (11*15)-(14*6)-(0.2*15*7.5)             # Bending moment in K-ft\n",
-      "print \"Bending moment at section D\", M, \"k-ft\"\n",
-      "V1 = -9+(0.2*15)                            # Shear firce from alternative method in k\n",
-      "M1 = (9*9)-(0.2*7.5*15)                     # Bending moment from alternative method in k-ft"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Shear force at section D -6.0 k\n",
-        "Bending moment at section D 58.5 k-ft\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 4.7"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "Shear force and bending moments\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "\n",
-      "q = 1                   # Uniform load intensity in k/ft\n",
-      "M0 = 12                 # Couple in k-ft\n",
-      "Rb = 5.25               # Reaction at B in k\n",
-      "Rc = 1.25               # Reaction at C in k\n",
-      "b = 4                   # Length of section AB in ft\n",
-      "\n",
-      "#calculation\n",
-      "\n",
-      "Mb = -(q*(b**2))/2      # Moment acting at B\n",
-      "\n",
-      "#Result\n",
-      "print \"Bending moment at B\", Mb, \"k-ft\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Bending moment at B -8 k-ft\n"
-       ]
-      }
-     ],
-     "prompt_number": 2
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Testing_the_interface/chapter4_1.ipynb b/Testing_the_interface/chapter4_1.ipynb
deleted file mode 100755
index e9b7e3e0..00000000
--- a/Testing_the_interface/chapter4_1.ipynb
+++ /dev/null
@@ -1,116 +0,0 @@
-{
- "metadata": {
-  "name": ""
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 4: Shear Forces and Bending Moments"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 4.3, page no. 275"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "Finding shear force V and bending movement M at cross section D located 115 ft from left-hand behind support\n",
-      "\"\"\"\n",
-      "\n",
-      "import math\n",
-      "\n",
-      "#initialisation\n",
-      "\n",
-      "q = 0.2                     # Uniform load intensity in K/ft\n",
-      "P = 14                      # Concentrated load in k\n",
-      "Ra = 11                     # Reaction at A from wquation of equilibrium\n",
-      "Rb = 9                      # Reaction at B from wquation of equilibrium\n",
-      "\n",
-      "#calculation\n",
-      "V = 11 - 14 - (0.2*15)      # shear force in k\n",
-      "\n",
-      "print \"Shear force at section D\", V, \"k\"\n",
-      "M = (11*15)-(14*6)-(0.2*15*7.5)             # Bending moment in K-ft\n",
-      "print \"Bending moment at section D\", M, \"k-ft\"\n",
-      "V1 = -9+(0.2*15)                            # Shear firce from alternative method in k\n",
-      "M1 = (9*9)-(0.2*7.5*15)                     # Bending moment from alternative method in k-ft"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Shear force at section D -6.0 k\n",
-        "Bending moment at section D 58.5 k-ft\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 4.7"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "Shear force and bending moments\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "\n",
-      "q = 1                   # Uniform load intensity in k/ft\n",
-      "M0 = 12                 # Couple in k-ft\n",
-      "Rb = 5.25               # Reaction at B in k\n",
-      "Rc = 1.25               # Reaction at C in k\n",
-      "b = 4                   # Length of section AB in ft\n",
-      "\n",
-      "#calculation\n",
-      "\n",
-      "Mb = -(q*(b**2))/2      # Moment acting at B\n",
-      "\n",
-      "#Result\n",
-      "print \"Bending moment at B\", Mb, \"k-ft\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Bending moment at B -8 k-ft\n"
-       ]
-      }
-     ],
-     "prompt_number": 2
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Testing_the_interface/chapter4_2.ipynb b/Testing_the_interface/chapter4_2.ipynb
deleted file mode 100755
index e9b7e3e0..00000000
--- a/Testing_the_interface/chapter4_2.ipynb
+++ /dev/null
@@ -1,116 +0,0 @@
-{
- "metadata": {
-  "name": ""
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 4: Shear Forces and Bending Moments"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 4.3, page no. 275"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "Finding shear force V and bending movement M at cross section D located 115 ft from left-hand behind support\n",
-      "\"\"\"\n",
-      "\n",
-      "import math\n",
-      "\n",
-      "#initialisation\n",
-      "\n",
-      "q = 0.2                     # Uniform load intensity in K/ft\n",
-      "P = 14                      # Concentrated load in k\n",
-      "Ra = 11                     # Reaction at A from wquation of equilibrium\n",
-      "Rb = 9                      # Reaction at B from wquation of equilibrium\n",
-      "\n",
-      "#calculation\n",
-      "V = 11 - 14 - (0.2*15)      # shear force in k\n",
-      "\n",
-      "print \"Shear force at section D\", V, \"k\"\n",
-      "M = (11*15)-(14*6)-(0.2*15*7.5)             # Bending moment in K-ft\n",
-      "print \"Bending moment at section D\", M, \"k-ft\"\n",
-      "V1 = -9+(0.2*15)                            # Shear firce from alternative method in k\n",
-      "M1 = (9*9)-(0.2*7.5*15)                     # Bending moment from alternative method in k-ft"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Shear force at section D -6.0 k\n",
-        "Bending moment at section D 58.5 k-ft\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 4.7"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "Shear force and bending moments\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "\n",
-      "q = 1                   # Uniform load intensity in k/ft\n",
-      "M0 = 12                 # Couple in k-ft\n",
-      "Rb = 5.25               # Reaction at B in k\n",
-      "Rc = 1.25               # Reaction at C in k\n",
-      "b = 4                   # Length of section AB in ft\n",
-      "\n",
-      "#calculation\n",
-      "\n",
-      "Mb = -(q*(b**2))/2      # Moment acting at B\n",
-      "\n",
-      "#Result\n",
-      "print \"Bending moment at B\", Mb, \"k-ft\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Bending moment at B -8 k-ft\n"
-       ]
-      }
-     ],
-     "prompt_number": 2
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Testing_the_interface/chapter4_3.ipynb b/Testing_the_interface/chapter4_3.ipynb
deleted file mode 100755
index e9b7e3e0..00000000
--- a/Testing_the_interface/chapter4_3.ipynb
+++ /dev/null
@@ -1,116 +0,0 @@
-{
- "metadata": {
-  "name": ""
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 4: Shear Forces and Bending Moments"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 4.3, page no. 275"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "Finding shear force V and bending movement M at cross section D located 115 ft from left-hand behind support\n",
-      "\"\"\"\n",
-      "\n",
-      "import math\n",
-      "\n",
-      "#initialisation\n",
-      "\n",
-      "q = 0.2                     # Uniform load intensity in K/ft\n",
-      "P = 14                      # Concentrated load in k\n",
-      "Ra = 11                     # Reaction at A from wquation of equilibrium\n",
-      "Rb = 9                      # Reaction at B from wquation of equilibrium\n",
-      "\n",
-      "#calculation\n",
-      "V = 11 - 14 - (0.2*15)      # shear force in k\n",
-      "\n",
-      "print \"Shear force at section D\", V, \"k\"\n",
-      "M = (11*15)-(14*6)-(0.2*15*7.5)             # Bending moment in K-ft\n",
-      "print \"Bending moment at section D\", M, \"k-ft\"\n",
-      "V1 = -9+(0.2*15)                            # Shear firce from alternative method in k\n",
-      "M1 = (9*9)-(0.2*7.5*15)                     # Bending moment from alternative method in k-ft"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Shear force at section D -6.0 k\n",
-        "Bending moment at section D 58.5 k-ft\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 4.7"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "Shear force and bending moments\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "\n",
-      "q = 1                   # Uniform load intensity in k/ft\n",
-      "M0 = 12                 # Couple in k-ft\n",
-      "Rb = 5.25               # Reaction at B in k\n",
-      "Rc = 1.25               # Reaction at C in k\n",
-      "b = 4                   # Length of section AB in ft\n",
-      "\n",
-      "#calculation\n",
-      "\n",
-      "Mb = -(q*(b**2))/2      # Moment acting at B\n",
-      "\n",
-      "#Result\n",
-      "print \"Bending moment at B\", Mb, \"k-ft\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Bending moment at B -8 k-ft\n"
-       ]
-      }
-     ],
-     "prompt_number": 2
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Testing_the_interface/chapter5.ipynb b/Testing_the_interface/chapter5.ipynb
deleted file mode 100755
index 9042fcb6..00000000
--- a/Testing_the_interface/chapter5.ipynb
+++ /dev/null
@@ -1,800 +0,0 @@
-{
- "metadata": {
-  "name": ""
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 5: Stresses in Beams Basic Topics"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.1, page no. 307"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculate radius of curvature, curvature & deflection of beam\n",
-      "\"\"\"\n",
-      "\n",
-      "import math\n",
-      "import numpy\n",
-      "\n",
-      "#initialisation\n",
-      "\n",
-      "L = 8.0                       # length of beam in ft\n",
-      "h = 6.0                       # Height of beam in inch\n",
-      "e = 0.00125                   # elongation on the bottom surface of the beam\n",
-      "y = -3.0                      # Dismath.tance of the bottom surface to the neutral surface of the beam in inch\n",
-      "\n",
-      "#Calculations\n",
-      "r = -(y/e)                    # Radius of curvature\n",
-      "print \"radius of curvature is\", round(r), \"inch\"\n",
-      "k = 1/r                     # curvature in in-1\n",
-      "print \"curvature\", round(k,5), \"ft-1\"\n",
-      "theta = numpy.degrees(numpy.arcsin(((L*12.0)/(2.0*r))))         # angle in degree\n",
-      "print \"Angle of twist\", round(theta,3), \"degree\"\n",
-      "my_del = r*(1-math.cos(math.radians(theta)))       #Deflection in inch\n",
-      "print \"Deflection in the beam is \", round(my_del,4), \"inch\" "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "radius of curvature is 2400.0 inch\n",
-        "curvature 0.00042 ft-1\n",
-        "Angle of twist 1.146 degree\n",
-        "Deflection in the beam is  0.48 inch\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.2, page no. 315"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "Evaluate bending moment & maximum bending stress in the wire\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "d = 0.004                       # thickness of wire in m\n",
-      "R0 = 0.5                        # radius of cylinder in m\n",
-      "E = 200e09                      # Modulus of elasticity of steel\n",
-      "s = 1200e06                     # proportional limit of steel\n",
-      "\n",
-      "#calculation\n",
-      "\n",
-      "M = (math.pi*E*d**4)/(32*(2*R0+d))      # Bending moment in wire in N-m\n",
-      "print \"Bending moment in the wire is \", round(M,2), \"N-m\"\n",
-      "s_max = (E*d)/(2*R0+d)                  # Maximum bending stress in wire in Pa\n",
-      "print \"Maximum bending stress in the wire is %e\" %(s_max), \"Pa\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Bending moment in the wire is  5.01 N-m\n",
-        "Maximum bending stress in the wire is 7.968127e+08 Pa\n"
-       ]
-      }
-     ],
-     "prompt_number": 10
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.3, page no. 316"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "find maximum tensile and compressive stress in the beam\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "L = 22                          # Span of beam in ft\n",
-      "q = 1.5                         # Uniform load intensity in k/ft\n",
-      "P = 12                          # Concentrated in k\n",
-      "b = 8.75                        # width of cross section of beam in inch\n",
-      "h = 27                          # height of cross section of beam in inch\n",
-      "Ra = 23.59                      # Reaction at point A\n",
-      "Rb = 21.41                      # Reacyion at point B\n",
-      "Mmax = 151.6                    # Maximum bending moment\n",
-      "\n",
-      "#calculation\n",
-      "\n",
-      "S = (b*h**2)/6                  # Section modulus\n",
-      "s = (Mmax*12)/S                 # stress in k\n",
-      "st = s*1000                     # Tensile stress\n",
-      "print \"Maximum tensile stress in the beam\", round(st), \"psi\"\n",
-      "sc = -s*1000                    # Compressive stress\n",
-      "print \"Maximum compressive stress in the beam\", round(sc), \"psi\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum tensile stress in the beam 1711.0 psi\n",
-        "Maximum compressive stress in the beam -1711.0 psi\n"
-       ]
-      }
-     ],
-     "prompt_number": 11
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.4, page no. 318"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "because of uniform load in the beam, calculate maximum tensile & compressive stress\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "q = 3200.0                        # Uniform load intensity in N/m\n",
-      "b = 0.3                           # width of beam in m\n",
-      "h = 0.08                          # Height of the beam in m\n",
-      "t = 0.012                         # thickness of beam in m\n",
-      "Ra = 3600.0                       # Reaction at A in N\n",
-      "Rb = 10800.0                      # Reaction at B in N\n",
-      "Mpos = 2025.0                     # Moment in Nm\n",
-      "Mneg = -3600.0                    # Moment in Nm\n",
-      "\n",
-      "#calculation\n",
-      "y1 = t/2.0\n",
-      "A1 = (b-2*t)*t  \n",
-      "y2 = h/2\n",
-      "A2 = h*t  \n",
-      "A3 = A2  \n",
-      "c1 = ((y1*A1)+(2*y2*A2))/((A1)+(2*A2))\n",
-      "c2 = h - c1 \n",
-      "Ic1 = (b-2*t)*(t**3)*(1.0/12.0)\n",
-      "d1 = c1-(t/2.0)\n",
-      "Iz1 = (Ic1)+(A1*(d1**2))\n",
-      "Iz2 = 956600e-12\n",
-      "Iz3 = Iz2 \n",
-      "Iz = Iz1 + Iz2 + Iz3                # Moment of inertia of the beam cross section\n",
-      "\n",
-      "# Section Modulli\n",
-      "S1 = Iz / c1                        # for the top surface\n",
-      "S2 = Iz / c2                        # for the bottom surface\n",
-      "\n",
-      "# Maximum stresses for the positive section\n",
-      "st = Mpos / S2 \n",
-      "print \"Maximum tensile stress in the beam in positive section is\", st, \"Pa\"\n",
-      "sc = -Mpos / S1 \n",
-      "print \"Maximum compressive stress in the beam in positive section is\", sc, \"Pa\"\n",
-      "\n",
-      "# Maximum stresses for the negative section\n",
-      "snt = -Mneg / S1 \n",
-      "print \"Maximum tensile stress in the beam in negative section is\", snt, \"Pa\"\n",
-      "snc = Mneg / S2 \n",
-      "print \"Maximum compressive stress in the beam in negative section is\", snc, \"Pa\"\n",
-      "\n",
-      "# Conclusion\n",
-      "st_max = st\n",
-      "sc_max = snc"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum tensile stress in the beam in positive section is 50468539.6422 Pa\n",
-        "Maximum compressive stress in the beam in positive section is -15157118.8248 Pa\n",
-        "Maximum tensile stress in the beam in negative section is 26945989.0219 Pa\n",
-        "Maximum compressive stress in the beam in negative section is -89721848.2528 Pa\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Exampe 5.5, page no. 325"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "choose a suitable size for the beam\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "L = 12                      # Length of beam in ft\n",
-      "q = 420                     # Uniform load intensity in lb/ft\n",
-      "s = 1800                    # Allowable bending stress in psi\n",
-      "w = 35                      # weight of wood in lb/ft3\n",
-      "\n",
-      "#calculation\n",
-      "M = (q*L**2*12)/8           # Bending moment in lb-in\n",
-      "S = M/s                     # Section Modulli in in3\n",
-      "\n",
-      "# From Appendix F\n",
-      "q1 = 426.8                  # New uniform load intensity in lb/ft\n",
-      "S1 = S*(q1/q)               # New section modulli in in3\n",
-      "\n",
-      "# From reference to appendix F, a beam of cross section 3*12 inch is selected\n",
-      "print (\"Beam of crosssection 3*12 is sufficient\")"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Beam of crosssection 3*12 is sufficient\n"
-       ]
-      }
-     ],
-     "prompt_number": 6
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.6, page no. 326"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "find min. req. diameter of the woodpost & req. outer diameter of aluminum tube\n",
-      "\"\"\"\n",
-      "\n",
-      "import math\n",
-      "\n",
-      "#initialisation\n",
-      "P = 12000                           # Lataeral load at the upper end in N\n",
-      "h = 2.5                             # Height of post in m\n",
-      "Mmax = P*h                          # Maximum bending moment in Nm\n",
-      "\n",
-      "#calculation\n",
-      "# Part (a) : Wood Post\n",
-      "s1 = 15e06                          # Maximum allowable stress in Pa\n",
-      "S1 = Mmax/s1                        # Section Modulli in m3\n",
-      "d1 = ((32.0*S1)/math.pi)**(1.0/3.0)       # diameter in m\n",
-      "print \"the minimum required diameter d1 of the wood post is\", round(d1,3), \"m\"\n",
-      "\n",
-      "# Part (b) : Alluminium tube\n",
-      "s2 = 50e06                          # Maximum allowable stress in Pa\n",
-      "S2 = Mmax/s2                        # Section Modulli in m3\n",
-      "d2 = (S2/0.06712)**(1.0/3.0)            # diameter in meter.....(1) \n",
-      "print \"minimum required outer diameter d2 of the aluminum tube is\", round(d2,3),\"m\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the minimum required diameter d1 of the wood post is 0.273 m\n",
-        "minimum required outer diameter d2 of the aluminum tube is 0.208 m\n"
-       ]
-      }
-     ],
-     "prompt_number": 18
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.7, page no. 326"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "evaluate and select a structural steel beam of wide-flange shape to support the loads\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "q = 2000.0                        # Uniform load intensity in lb/ft\n",
-      "s = 18000.0                       # Maximum allowable load in Psi\n",
-      "Ra = 18860.0                      # Reaction at point  A\n",
-      "Rb = 17140.0                      # Reaction at point  B\n",
-      "\n",
-      "#calculation\n",
-      "x1 = Ra/q                         # Distance in ft from left end to the point of zero shear\n",
-      "Mmax = (Ra*x1)-((q*(x1**2))/2.0)  # Maximum bending moment in lb-ft\n",
-      "S = (Mmax*12.0)/s                 # Section Modulli in in3\n",
-      "\n",
-      "# Trial Beam\n",
-      "Ra_t = 19380.0                            # Reaction at point  A\n",
-      "Rb_t = 17670.0                            # Reaction at point  B\n",
-      "\n",
-      "#in Python the value for x1 differes by some points and hence the subsequent results differ\n",
-      "x1_t = Ra_t/q                             # Distance in ft from left end to the point of zero shear\n",
-      "Mmax_t = (Ra_t*x1_t)-((q*(x1_t**2))/2.0)  # Maximum bending moment in lb-ft\n",
-      "S_t = (Mmax_t*12.0)/s                     # Section Modulli in in3\n",
-      "# From table E beam 12*50 is selected \n",
-      "print \"Beam of crosssection 12*50 is selected with section modulli\", round(S_t,1), \"in^3\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Beam of crosssection 12*50 is selected with section modulli 62.6 in^3\n"
-       ]
-      }
-     ],
-     "prompt_number": 8
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.8, page 329"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "find min. req. dimension of the posts\n",
-      "\"\"\"\n",
-      "\n",
-      "import math\n",
-      "\n",
-      "#initialisation \n",
-      "g = 9810                        # Specific weight of water in N/m3\n",
-      "h = 2                           # Height of dam in m\n",
-      "s = 0.8                         # Dismath.tance between square cross section in m\n",
-      "sa = 8e06                       # Maximum allowable stress in Pa\n",
-      "\n",
-      "#Calculations\n",
-      "b = ((g*(h**3)*s)/sa)**(1.0/3.0)    # Dimension of croossection in m\n",
-      "\n",
-      "#Result\n",
-      "print \"the minimum required dimension b of the posts\", round(b,3), \"m\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the minimum required dimension b of the posts 0.199 m\n"
-       ]
-      }
-     ],
-     "prompt_number": 15
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.11, page no. 341"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "find normal & shear stress at point C\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "L = 3                       # Span of beam in ft\n",
-      "q = 160                     # Uniform load intensity in lb/in\n",
-      "b = 1                       # Width of cross section\n",
-      "h = 4                       # Height of cross section\n",
-      "\n",
-      "# Calculations from chapter 4\n",
-      "Mc = 17920                  # Bending moment in ld-in\n",
-      "Vc = -1600                  # Loading in lb\n",
-      "I = (b*(h**3))/12.0           # Moment of inertia in in4\n",
-      "sc = -(Mc*1)/I              # Compressive stress at point C in psi\n",
-      "Ac = 1*1                    # Area of section C in inch2\n",
-      "yc = 1.5                    # dismath.tance between midlayers od section C and cross section of beam\n",
-      "Qc = Ac*yc                  # First moment of C cross section in inch3\n",
-      "tc = (Vc*Qc)/(I*b)          # Shear stress in Psi\n",
-      "print \"Normal stress at C\", sc, \"psi\"\n",
-      "print \"Shear stress at C\", tc, \"psi\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Normal stress at C -3360.0 psi\n",
-        "Shear stress at C -450.0 psi\n"
-       ]
-      }
-     ],
-     "prompt_number": 10
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.12, page no. 342"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculate max. permissible value\n",
-      "\"\"\"\n",
-      "\n",
-      "import math\n",
-      "\n",
-      "#initialisation\n",
-      "s = 11e06                       # allowable tensile stress in pa\n",
-      "t = 1.2e06                      # allowable shear stress in pa\n",
-      "b = 0.1                         # Width of cross section in m\n",
-      "h = 0.15                        # Height of cross section in m\n",
-      "a = 0.5                         # in m\n",
-      "\n",
-      "#Calculations\n",
-      "P_bending = (s*b*h**2)/(6.0*a)    # Bending stress in N\n",
-      "P_shear = (2*t*b*h)/3.0           # shear stress in N\n",
-      "Pmax = P_bending                # Because bending stress governs the design\n",
-      "\n",
-      "#Result\n",
-      "print \"the maximum permissible value Pmax of the loads\", Pmax, \"N\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the maximum permissible value Pmax of the loads 8250.0 N\n"
-       ]
-      }
-     ],
-     "prompt_number": 11
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.13, page no. 345"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "evaluate max. shear stress in the pole & diameter of solid pole\n",
-      "\"\"\"\n",
-      "\n",
-      "import math\n",
-      "\n",
-      "#initialisation\n",
-      "d2 = 4                      # Outer diameter in inch\n",
-      "d1 = 3.2                    # Inner diameter in inch\n",
-      "r2 = d2/2                   # Outer radius in inch\n",
-      "r1 = d1/2                   # inner radius in inch\n",
-      "P = 1500                    # Horizontal force in lb\n",
-      "\n",
-      "#calculation\n",
-      "# Part (a)\n",
-      "t_max = ((r2**2+(r2*r1)+r1**2)*4*P)/(3*math.pi*((r2**4)-(r1**4)))  # Mximum shear stress in Psi\n",
-      "print \"Maximum shear stress in the pole is\", round(t_max), \"psi\"\n",
-      "\n",
-      "# Part (b)\n",
-      "d0 = math.sqrt((16*P)/(3*math.pi*t_max))  # Diameter of solid circular cross section in meter\n",
-      "print \"Diameter of solid circular cross section is \", round(d0,2), \"m\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum shear stress in the pole is 658.0 psi\n",
-        "Diameter of solid circular cross section is  1.97 m\n"
-       ]
-      }
-     ],
-     "prompt_number": 20
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.14, page no. 351"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "maximum shear stress, minimum shear stress, and total shear force in the web.\n",
-      "\"\"\"\n",
-      "\n",
-      "import math\n",
-      "\n",
-      "#initialisation\n",
-      "b = 0.165                   # in m\n",
-      "h = 0.320                   # in m\n",
-      "h1 = 0.290                  # in m\n",
-      "t = 0.0075                  #  in m\n",
-      "V = 45000.0                   # Vertical force in N\n",
-      "\n",
-      "#calculation\n",
-      "I = (1.0/12.0)*((b*(h**3))-(b*(h1**3))+(t*(h1**3))) # Moment of inertia of the cros section\n",
-      "t_max = (V/(8.0*I*t))*((b*(h**2))-(b*(h1**2))+(t*(h1**2))) # Maximum shear stress in Pa\n",
-      "t_min = ((V*b)/(8*I*t))*(h**2-h1**2) # Minimum shear stress in Pa\n",
-      "T = ((t*h1)/3.0)*(2*t_max + t_min) # Total shear force in Pa\n",
-      "t_avg = V/(t*h1)  # Average shear stress in Pa\n",
-      "\n",
-      "#Result\n",
-      "print \"Maximum shear stress in the web is\", round(t_max,2), \"Pa\"\n",
-      "print \"Minimum shear stress in the web is\", round(t_min,2), \"Pa\"\n",
-      "print \"Total shear stress in the web is\", round(T,2), \"N\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum shear stress in the web is 20985785.26 Pa\n",
-        "Minimum shear stress in the web is 17359517.46 Pa\n",
-        "Total shear stress in the web is 43015.04 N\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.15, page no. 352"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "find shear stress at top of the web\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "V = 10000                   # Vertical shear force in lb\n",
-      "b = 4                       # in inch\n",
-      "t = 1                       # in inch\n",
-      "h = 8                       # in inch\n",
-      "h1 = 7                      # in inch\n",
-      "\n",
-      "#calculation\n",
-      "A = b*(h-h1) + t*h1                             # Area of cross section \n",
-      "Qaa = ((h+h1)/2.0)*b*(h-h1) + (h1/2.0)*(t*h1)       # First moment of cross section\n",
-      "c2 = Qaa/A                                      # Position of neutral axis in inch\n",
-      "c1 = h-c2                                       # Position of neutral axis in inch\n",
-      "Iaa = (b*h**3)/3.0 - ((b-t)*h1**3)/3.0              # Moment of inertia about the line aa\n",
-      "I = Iaa - A*c2**2                               # Moment of inertia of crosssection\n",
-      "Q1 = b*(h-h1)*(c1-((h-h1)/2.0))                   # First moment of area above the line nn\n",
-      "t1 = (V*Q1)/(I*t)                               # Shear stress at the top of web in Psi\n",
-      "Qmax = (t*c2)*(c2/2.0)                            # Maximum first moment of inertia below neutral axis\n",
-      "t_max = (V*Qmax)/(I*t)                          # Maximum Shear stress in Psi\n",
-      "\n",
-      "#Result\n",
-      "print \"Shear stress at the top of the web is\", round(t1), \"psi\"\n",
-      "print \"Maximum Shear stress in the web is\", round(t_max), \"Psi\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Shear stress at the top of the web is 1462.0 psi\n",
-        "Maximum Shear stress in the web is 1762.0 Psi\n"
-       ]
-      }
-     ],
-     "prompt_number": 24
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.16, page no. 357"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "maximum permissible longitudinal spacing of the screws\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "\n",
-      "Af = 40*180                     # Area of flange in mm2\n",
-      "V = 10500                       # Shear force acting on cross section\n",
-      "F = 800                         # Allowable load in shear\n",
-      "df = 120                        # Dismath.tance between centroid of flange and neutral axis in mm\n",
-      "\n",
-      "#calculation\n",
-      "Q = Af*df                       # First moment of cross section of flange\n",
-      "I = (1.0/12.0)*(210*280**3) - (1.0/12.0)*(180*200**3)  # Moment of inertia of entire cross section in mm4\n",
-      "f = (V*Q)/I                     # Shear flow\n",
-      "s = (2*F)/f                     # Spacing between the screw\n",
-      "\n",
-      "#Result\n",
-      "print \"The maximum permissible longitudinal spacing s of the screws is\", round(s,1), \"mm\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The maximum permissible longitudinal spacing s of the screws is 46.6 mm\n"
-       ]
-      }
-     ],
-     "prompt_number": 25
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.17, page no. 362"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "maximum tensile and compressive stress in the beam\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "L = 60                           # Length of beam in inch\n",
-      "d = 5.5                          # dismath.tance from the point of application of the load P to the longitudinal axis of the tube in inch\n",
-      "b = 6                            # Outer dimension of tube in inch\n",
-      "A = 20                           # Area of cross section of tube in inch\n",
-      "I = 86.67                        # Moment of inertia in in4\n",
-      "P = 1000                         # in lb\n",
-      "theta = 60                       # in degree\n",
-      "Ph = P*math.sin(math.radians(60)) # Horizontal component\n",
-      "Pv = P*math.cos(math.radians(60)) # Vertical component\n",
-      "\n",
-      "#Calculations\n",
-      "M0 = Ph*d                        # Moment in lb-in\n",
-      "y = -3                           # Point at which maximum tensile stress occur in inch\n",
-      "N = Ph                           # Axial force\n",
-      "M = 9870                         # Moment in lb-in\n",
-      "st_max = (N/A)-((M*y)/I)         # Maximum tensile stress in Psi\n",
-      "yc = 3                           # in inch\n",
-      "M1 = 5110                        # moment in lb-in\n",
-      "sc_left = (N/A)-((M*yc)/I)       # Stress at the left of point C in Psi\n",
-      "sc_right = -(M1*yc)/I            # Stress at the right of point C in Psi\n",
-      "sc_max = min(sc_left,sc_right)   # Because both are negative quantities\n",
-      "\n",
-      "#Result\n",
-      "print \"The maximum compressive stress in the beam is\", round(sc_max), \"psi\"\n",
-      "print \"The maximum tensile stress in the beam is\", round(st_max), \"psi\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The maximum compressive stress in the beam is -298.0 psi\n",
-        "The maximum tensile stress in the beam is 385.0 psi\n"
-       ]
-      }
-     ],
-     "prompt_number": 26
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Testing_the_interface/chapter5_1.ipynb b/Testing_the_interface/chapter5_1.ipynb
deleted file mode 100755
index 9042fcb6..00000000
--- a/Testing_the_interface/chapter5_1.ipynb
+++ /dev/null
@@ -1,800 +0,0 @@
-{
- "metadata": {
-  "name": ""
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 5: Stresses in Beams Basic Topics"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.1, page no. 307"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculate radius of curvature, curvature & deflection of beam\n",
-      "\"\"\"\n",
-      "\n",
-      "import math\n",
-      "import numpy\n",
-      "\n",
-      "#initialisation\n",
-      "\n",
-      "L = 8.0                       # length of beam in ft\n",
-      "h = 6.0                       # Height of beam in inch\n",
-      "e = 0.00125                   # elongation on the bottom surface of the beam\n",
-      "y = -3.0                      # Dismath.tance of the bottom surface to the neutral surface of the beam in inch\n",
-      "\n",
-      "#Calculations\n",
-      "r = -(y/e)                    # Radius of curvature\n",
-      "print \"radius of curvature is\", round(r), \"inch\"\n",
-      "k = 1/r                     # curvature in in-1\n",
-      "print \"curvature\", round(k,5), \"ft-1\"\n",
-      "theta = numpy.degrees(numpy.arcsin(((L*12.0)/(2.0*r))))         # angle in degree\n",
-      "print \"Angle of twist\", round(theta,3), \"degree\"\n",
-      "my_del = r*(1-math.cos(math.radians(theta)))       #Deflection in inch\n",
-      "print \"Deflection in the beam is \", round(my_del,4), \"inch\" "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "radius of curvature is 2400.0 inch\n",
-        "curvature 0.00042 ft-1\n",
-        "Angle of twist 1.146 degree\n",
-        "Deflection in the beam is  0.48 inch\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.2, page no. 315"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "Evaluate bending moment & maximum bending stress in the wire\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "d = 0.004                       # thickness of wire in m\n",
-      "R0 = 0.5                        # radius of cylinder in m\n",
-      "E = 200e09                      # Modulus of elasticity of steel\n",
-      "s = 1200e06                     # proportional limit of steel\n",
-      "\n",
-      "#calculation\n",
-      "\n",
-      "M = (math.pi*E*d**4)/(32*(2*R0+d))      # Bending moment in wire in N-m\n",
-      "print \"Bending moment in the wire is \", round(M,2), \"N-m\"\n",
-      "s_max = (E*d)/(2*R0+d)                  # Maximum bending stress in wire in Pa\n",
-      "print \"Maximum bending stress in the wire is %e\" %(s_max), \"Pa\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Bending moment in the wire is  5.01 N-m\n",
-        "Maximum bending stress in the wire is 7.968127e+08 Pa\n"
-       ]
-      }
-     ],
-     "prompt_number": 10
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.3, page no. 316"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "find maximum tensile and compressive stress in the beam\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "L = 22                          # Span of beam in ft\n",
-      "q = 1.5                         # Uniform load intensity in k/ft\n",
-      "P = 12                          # Concentrated in k\n",
-      "b = 8.75                        # width of cross section of beam in inch\n",
-      "h = 27                          # height of cross section of beam in inch\n",
-      "Ra = 23.59                      # Reaction at point A\n",
-      "Rb = 21.41                      # Reacyion at point B\n",
-      "Mmax = 151.6                    # Maximum bending moment\n",
-      "\n",
-      "#calculation\n",
-      "\n",
-      "S = (b*h**2)/6                  # Section modulus\n",
-      "s = (Mmax*12)/S                 # stress in k\n",
-      "st = s*1000                     # Tensile stress\n",
-      "print \"Maximum tensile stress in the beam\", round(st), \"psi\"\n",
-      "sc = -s*1000                    # Compressive stress\n",
-      "print \"Maximum compressive stress in the beam\", round(sc), \"psi\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum tensile stress in the beam 1711.0 psi\n",
-        "Maximum compressive stress in the beam -1711.0 psi\n"
-       ]
-      }
-     ],
-     "prompt_number": 11
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.4, page no. 318"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "because of uniform load in the beam, calculate maximum tensile & compressive stress\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "q = 3200.0                        # Uniform load intensity in N/m\n",
-      "b = 0.3                           # width of beam in m\n",
-      "h = 0.08                          # Height of the beam in m\n",
-      "t = 0.012                         # thickness of beam in m\n",
-      "Ra = 3600.0                       # Reaction at A in N\n",
-      "Rb = 10800.0                      # Reaction at B in N\n",
-      "Mpos = 2025.0                     # Moment in Nm\n",
-      "Mneg = -3600.0                    # Moment in Nm\n",
-      "\n",
-      "#calculation\n",
-      "y1 = t/2.0\n",
-      "A1 = (b-2*t)*t  \n",
-      "y2 = h/2\n",
-      "A2 = h*t  \n",
-      "A3 = A2  \n",
-      "c1 = ((y1*A1)+(2*y2*A2))/((A1)+(2*A2))\n",
-      "c2 = h - c1 \n",
-      "Ic1 = (b-2*t)*(t**3)*(1.0/12.0)\n",
-      "d1 = c1-(t/2.0)\n",
-      "Iz1 = (Ic1)+(A1*(d1**2))\n",
-      "Iz2 = 956600e-12\n",
-      "Iz3 = Iz2 \n",
-      "Iz = Iz1 + Iz2 + Iz3                # Moment of inertia of the beam cross section\n",
-      "\n",
-      "# Section Modulli\n",
-      "S1 = Iz / c1                        # for the top surface\n",
-      "S2 = Iz / c2                        # for the bottom surface\n",
-      "\n",
-      "# Maximum stresses for the positive section\n",
-      "st = Mpos / S2 \n",
-      "print \"Maximum tensile stress in the beam in positive section is\", st, \"Pa\"\n",
-      "sc = -Mpos / S1 \n",
-      "print \"Maximum compressive stress in the beam in positive section is\", sc, \"Pa\"\n",
-      "\n",
-      "# Maximum stresses for the negative section\n",
-      "snt = -Mneg / S1 \n",
-      "print \"Maximum tensile stress in the beam in negative section is\", snt, \"Pa\"\n",
-      "snc = Mneg / S2 \n",
-      "print \"Maximum compressive stress in the beam in negative section is\", snc, \"Pa\"\n",
-      "\n",
-      "# Conclusion\n",
-      "st_max = st\n",
-      "sc_max = snc"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum tensile stress in the beam in positive section is 50468539.6422 Pa\n",
-        "Maximum compressive stress in the beam in positive section is -15157118.8248 Pa\n",
-        "Maximum tensile stress in the beam in negative section is 26945989.0219 Pa\n",
-        "Maximum compressive stress in the beam in negative section is -89721848.2528 Pa\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Exampe 5.5, page no. 325"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "choose a suitable size for the beam\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "L = 12                      # Length of beam in ft\n",
-      "q = 420                     # Uniform load intensity in lb/ft\n",
-      "s = 1800                    # Allowable bending stress in psi\n",
-      "w = 35                      # weight of wood in lb/ft3\n",
-      "\n",
-      "#calculation\n",
-      "M = (q*L**2*12)/8           # Bending moment in lb-in\n",
-      "S = M/s                     # Section Modulli in in3\n",
-      "\n",
-      "# From Appendix F\n",
-      "q1 = 426.8                  # New uniform load intensity in lb/ft\n",
-      "S1 = S*(q1/q)               # New section modulli in in3\n",
-      "\n",
-      "# From reference to appendix F, a beam of cross section 3*12 inch is selected\n",
-      "print (\"Beam of crosssection 3*12 is sufficient\")"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Beam of crosssection 3*12 is sufficient\n"
-       ]
-      }
-     ],
-     "prompt_number": 6
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.6, page no. 326"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "find min. req. diameter of the woodpost & req. outer diameter of aluminum tube\n",
-      "\"\"\"\n",
-      "\n",
-      "import math\n",
-      "\n",
-      "#initialisation\n",
-      "P = 12000                           # Lataeral load at the upper end in N\n",
-      "h = 2.5                             # Height of post in m\n",
-      "Mmax = P*h                          # Maximum bending moment in Nm\n",
-      "\n",
-      "#calculation\n",
-      "# Part (a) : Wood Post\n",
-      "s1 = 15e06                          # Maximum allowable stress in Pa\n",
-      "S1 = Mmax/s1                        # Section Modulli in m3\n",
-      "d1 = ((32.0*S1)/math.pi)**(1.0/3.0)       # diameter in m\n",
-      "print \"the minimum required diameter d1 of the wood post is\", round(d1,3), \"m\"\n",
-      "\n",
-      "# Part (b) : Alluminium tube\n",
-      "s2 = 50e06                          # Maximum allowable stress in Pa\n",
-      "S2 = Mmax/s2                        # Section Modulli in m3\n",
-      "d2 = (S2/0.06712)**(1.0/3.0)            # diameter in meter.....(1) \n",
-      "print \"minimum required outer diameter d2 of the aluminum tube is\", round(d2,3),\"m\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the minimum required diameter d1 of the wood post is 0.273 m\n",
-        "minimum required outer diameter d2 of the aluminum tube is 0.208 m\n"
-       ]
-      }
-     ],
-     "prompt_number": 18
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.7, page no. 326"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "evaluate and select a structural steel beam of wide-flange shape to support the loads\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "q = 2000.0                        # Uniform load intensity in lb/ft\n",
-      "s = 18000.0                       # Maximum allowable load in Psi\n",
-      "Ra = 18860.0                      # Reaction at point  A\n",
-      "Rb = 17140.0                      # Reaction at point  B\n",
-      "\n",
-      "#calculation\n",
-      "x1 = Ra/q                         # Distance in ft from left end to the point of zero shear\n",
-      "Mmax = (Ra*x1)-((q*(x1**2))/2.0)  # Maximum bending moment in lb-ft\n",
-      "S = (Mmax*12.0)/s                 # Section Modulli in in3\n",
-      "\n",
-      "# Trial Beam\n",
-      "Ra_t = 19380.0                            # Reaction at point  A\n",
-      "Rb_t = 17670.0                            # Reaction at point  B\n",
-      "\n",
-      "#in Python the value for x1 differes by some points and hence the subsequent results differ\n",
-      "x1_t = Ra_t/q                             # Distance in ft from left end to the point of zero shear\n",
-      "Mmax_t = (Ra_t*x1_t)-((q*(x1_t**2))/2.0)  # Maximum bending moment in lb-ft\n",
-      "S_t = (Mmax_t*12.0)/s                     # Section Modulli in in3\n",
-      "# From table E beam 12*50 is selected \n",
-      "print \"Beam of crosssection 12*50 is selected with section modulli\", round(S_t,1), \"in^3\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Beam of crosssection 12*50 is selected with section modulli 62.6 in^3\n"
-       ]
-      }
-     ],
-     "prompt_number": 8
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.8, page 329"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "find min. req. dimension of the posts\n",
-      "\"\"\"\n",
-      "\n",
-      "import math\n",
-      "\n",
-      "#initialisation \n",
-      "g = 9810                        # Specific weight of water in N/m3\n",
-      "h = 2                           # Height of dam in m\n",
-      "s = 0.8                         # Dismath.tance between square cross section in m\n",
-      "sa = 8e06                       # Maximum allowable stress in Pa\n",
-      "\n",
-      "#Calculations\n",
-      "b = ((g*(h**3)*s)/sa)**(1.0/3.0)    # Dimension of croossection in m\n",
-      "\n",
-      "#Result\n",
-      "print \"the minimum required dimension b of the posts\", round(b,3), \"m\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the minimum required dimension b of the posts 0.199 m\n"
-       ]
-      }
-     ],
-     "prompt_number": 15
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.11, page no. 341"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "find normal & shear stress at point C\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "L = 3                       # Span of beam in ft\n",
-      "q = 160                     # Uniform load intensity in lb/in\n",
-      "b = 1                       # Width of cross section\n",
-      "h = 4                       # Height of cross section\n",
-      "\n",
-      "# Calculations from chapter 4\n",
-      "Mc = 17920                  # Bending moment in ld-in\n",
-      "Vc = -1600                  # Loading in lb\n",
-      "I = (b*(h**3))/12.0           # Moment of inertia in in4\n",
-      "sc = -(Mc*1)/I              # Compressive stress at point C in psi\n",
-      "Ac = 1*1                    # Area of section C in inch2\n",
-      "yc = 1.5                    # dismath.tance between midlayers od section C and cross section of beam\n",
-      "Qc = Ac*yc                  # First moment of C cross section in inch3\n",
-      "tc = (Vc*Qc)/(I*b)          # Shear stress in Psi\n",
-      "print \"Normal stress at C\", sc, \"psi\"\n",
-      "print \"Shear stress at C\", tc, \"psi\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Normal stress at C -3360.0 psi\n",
-        "Shear stress at C -450.0 psi\n"
-       ]
-      }
-     ],
-     "prompt_number": 10
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.12, page no. 342"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculate max. permissible value\n",
-      "\"\"\"\n",
-      "\n",
-      "import math\n",
-      "\n",
-      "#initialisation\n",
-      "s = 11e06                       # allowable tensile stress in pa\n",
-      "t = 1.2e06                      # allowable shear stress in pa\n",
-      "b = 0.1                         # Width of cross section in m\n",
-      "h = 0.15                        # Height of cross section in m\n",
-      "a = 0.5                         # in m\n",
-      "\n",
-      "#Calculations\n",
-      "P_bending = (s*b*h**2)/(6.0*a)    # Bending stress in N\n",
-      "P_shear = (2*t*b*h)/3.0           # shear stress in N\n",
-      "Pmax = P_bending                # Because bending stress governs the design\n",
-      "\n",
-      "#Result\n",
-      "print \"the maximum permissible value Pmax of the loads\", Pmax, \"N\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the maximum permissible value Pmax of the loads 8250.0 N\n"
-       ]
-      }
-     ],
-     "prompt_number": 11
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.13, page no. 345"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "evaluate max. shear stress in the pole & diameter of solid pole\n",
-      "\"\"\"\n",
-      "\n",
-      "import math\n",
-      "\n",
-      "#initialisation\n",
-      "d2 = 4                      # Outer diameter in inch\n",
-      "d1 = 3.2                    # Inner diameter in inch\n",
-      "r2 = d2/2                   # Outer radius in inch\n",
-      "r1 = d1/2                   # inner radius in inch\n",
-      "P = 1500                    # Horizontal force in lb\n",
-      "\n",
-      "#calculation\n",
-      "# Part (a)\n",
-      "t_max = ((r2**2+(r2*r1)+r1**2)*4*P)/(3*math.pi*((r2**4)-(r1**4)))  # Mximum shear stress in Psi\n",
-      "print \"Maximum shear stress in the pole is\", round(t_max), \"psi\"\n",
-      "\n",
-      "# Part (b)\n",
-      "d0 = math.sqrt((16*P)/(3*math.pi*t_max))  # Diameter of solid circular cross section in meter\n",
-      "print \"Diameter of solid circular cross section is \", round(d0,2), \"m\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum shear stress in the pole is 658.0 psi\n",
-        "Diameter of solid circular cross section is  1.97 m\n"
-       ]
-      }
-     ],
-     "prompt_number": 20
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.14, page no. 351"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "maximum shear stress, minimum shear stress, and total shear force in the web.\n",
-      "\"\"\"\n",
-      "\n",
-      "import math\n",
-      "\n",
-      "#initialisation\n",
-      "b = 0.165                   # in m\n",
-      "h = 0.320                   # in m\n",
-      "h1 = 0.290                  # in m\n",
-      "t = 0.0075                  #  in m\n",
-      "V = 45000.0                   # Vertical force in N\n",
-      "\n",
-      "#calculation\n",
-      "I = (1.0/12.0)*((b*(h**3))-(b*(h1**3))+(t*(h1**3))) # Moment of inertia of the cros section\n",
-      "t_max = (V/(8.0*I*t))*((b*(h**2))-(b*(h1**2))+(t*(h1**2))) # Maximum shear stress in Pa\n",
-      "t_min = ((V*b)/(8*I*t))*(h**2-h1**2) # Minimum shear stress in Pa\n",
-      "T = ((t*h1)/3.0)*(2*t_max + t_min) # Total shear force in Pa\n",
-      "t_avg = V/(t*h1)  # Average shear stress in Pa\n",
-      "\n",
-      "#Result\n",
-      "print \"Maximum shear stress in the web is\", round(t_max,2), \"Pa\"\n",
-      "print \"Minimum shear stress in the web is\", round(t_min,2), \"Pa\"\n",
-      "print \"Total shear stress in the web is\", round(T,2), \"N\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum shear stress in the web is 20985785.26 Pa\n",
-        "Minimum shear stress in the web is 17359517.46 Pa\n",
-        "Total shear stress in the web is 43015.04 N\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.15, page no. 352"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "find shear stress at top of the web\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "V = 10000                   # Vertical shear force in lb\n",
-      "b = 4                       # in inch\n",
-      "t = 1                       # in inch\n",
-      "h = 8                       # in inch\n",
-      "h1 = 7                      # in inch\n",
-      "\n",
-      "#calculation\n",
-      "A = b*(h-h1) + t*h1                             # Area of cross section \n",
-      "Qaa = ((h+h1)/2.0)*b*(h-h1) + (h1/2.0)*(t*h1)       # First moment of cross section\n",
-      "c2 = Qaa/A                                      # Position of neutral axis in inch\n",
-      "c1 = h-c2                                       # Position of neutral axis in inch\n",
-      "Iaa = (b*h**3)/3.0 - ((b-t)*h1**3)/3.0              # Moment of inertia about the line aa\n",
-      "I = Iaa - A*c2**2                               # Moment of inertia of crosssection\n",
-      "Q1 = b*(h-h1)*(c1-((h-h1)/2.0))                   # First moment of area above the line nn\n",
-      "t1 = (V*Q1)/(I*t)                               # Shear stress at the top of web in Psi\n",
-      "Qmax = (t*c2)*(c2/2.0)                            # Maximum first moment of inertia below neutral axis\n",
-      "t_max = (V*Qmax)/(I*t)                          # Maximum Shear stress in Psi\n",
-      "\n",
-      "#Result\n",
-      "print \"Shear stress at the top of the web is\", round(t1), \"psi\"\n",
-      "print \"Maximum Shear stress in the web is\", round(t_max), \"Psi\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Shear stress at the top of the web is 1462.0 psi\n",
-        "Maximum Shear stress in the web is 1762.0 Psi\n"
-       ]
-      }
-     ],
-     "prompt_number": 24
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.16, page no. 357"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "maximum permissible longitudinal spacing of the screws\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "\n",
-      "Af = 40*180                     # Area of flange in mm2\n",
-      "V = 10500                       # Shear force acting on cross section\n",
-      "F = 800                         # Allowable load in shear\n",
-      "df = 120                        # Dismath.tance between centroid of flange and neutral axis in mm\n",
-      "\n",
-      "#calculation\n",
-      "Q = Af*df                       # First moment of cross section of flange\n",
-      "I = (1.0/12.0)*(210*280**3) - (1.0/12.0)*(180*200**3)  # Moment of inertia of entire cross section in mm4\n",
-      "f = (V*Q)/I                     # Shear flow\n",
-      "s = (2*F)/f                     # Spacing between the screw\n",
-      "\n",
-      "#Result\n",
-      "print \"The maximum permissible longitudinal spacing s of the screws is\", round(s,1), \"mm\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The maximum permissible longitudinal spacing s of the screws is 46.6 mm\n"
-       ]
-      }
-     ],
-     "prompt_number": 25
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.17, page no. 362"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "maximum tensile and compressive stress in the beam\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "L = 60                           # Length of beam in inch\n",
-      "d = 5.5                          # dismath.tance from the point of application of the load P to the longitudinal axis of the tube in inch\n",
-      "b = 6                            # Outer dimension of tube in inch\n",
-      "A = 20                           # Area of cross section of tube in inch\n",
-      "I = 86.67                        # Moment of inertia in in4\n",
-      "P = 1000                         # in lb\n",
-      "theta = 60                       # in degree\n",
-      "Ph = P*math.sin(math.radians(60)) # Horizontal component\n",
-      "Pv = P*math.cos(math.radians(60)) # Vertical component\n",
-      "\n",
-      "#Calculations\n",
-      "M0 = Ph*d                        # Moment in lb-in\n",
-      "y = -3                           # Point at which maximum tensile stress occur in inch\n",
-      "N = Ph                           # Axial force\n",
-      "M = 9870                         # Moment in lb-in\n",
-      "st_max = (N/A)-((M*y)/I)         # Maximum tensile stress in Psi\n",
-      "yc = 3                           # in inch\n",
-      "M1 = 5110                        # moment in lb-in\n",
-      "sc_left = (N/A)-((M*yc)/I)       # Stress at the left of point C in Psi\n",
-      "sc_right = -(M1*yc)/I            # Stress at the right of point C in Psi\n",
-      "sc_max = min(sc_left,sc_right)   # Because both are negative quantities\n",
-      "\n",
-      "#Result\n",
-      "print \"The maximum compressive stress in the beam is\", round(sc_max), \"psi\"\n",
-      "print \"The maximum tensile stress in the beam is\", round(st_max), \"psi\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The maximum compressive stress in the beam is -298.0 psi\n",
-        "The maximum tensile stress in the beam is 385.0 psi\n"
-       ]
-      }
-     ],
-     "prompt_number": 26
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Testing_the_interface/chapter5_2.ipynb b/Testing_the_interface/chapter5_2.ipynb
deleted file mode 100755
index 9042fcb6..00000000
--- a/Testing_the_interface/chapter5_2.ipynb
+++ /dev/null
@@ -1,800 +0,0 @@
-{
- "metadata": {
-  "name": ""
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 5: Stresses in Beams Basic Topics"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.1, page no. 307"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculate radius of curvature, curvature & deflection of beam\n",
-      "\"\"\"\n",
-      "\n",
-      "import math\n",
-      "import numpy\n",
-      "\n",
-      "#initialisation\n",
-      "\n",
-      "L = 8.0                       # length of beam in ft\n",
-      "h = 6.0                       # Height of beam in inch\n",
-      "e = 0.00125                   # elongation on the bottom surface of the beam\n",
-      "y = -3.0                      # Dismath.tance of the bottom surface to the neutral surface of the beam in inch\n",
-      "\n",
-      "#Calculations\n",
-      "r = -(y/e)                    # Radius of curvature\n",
-      "print \"radius of curvature is\", round(r), \"inch\"\n",
-      "k = 1/r                     # curvature in in-1\n",
-      "print \"curvature\", round(k,5), \"ft-1\"\n",
-      "theta = numpy.degrees(numpy.arcsin(((L*12.0)/(2.0*r))))         # angle in degree\n",
-      "print \"Angle of twist\", round(theta,3), \"degree\"\n",
-      "my_del = r*(1-math.cos(math.radians(theta)))       #Deflection in inch\n",
-      "print \"Deflection in the beam is \", round(my_del,4), \"inch\" "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "radius of curvature is 2400.0 inch\n",
-        "curvature 0.00042 ft-1\n",
-        "Angle of twist 1.146 degree\n",
-        "Deflection in the beam is  0.48 inch\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.2, page no. 315"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "Evaluate bending moment & maximum bending stress in the wire\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "d = 0.004                       # thickness of wire in m\n",
-      "R0 = 0.5                        # radius of cylinder in m\n",
-      "E = 200e09                      # Modulus of elasticity of steel\n",
-      "s = 1200e06                     # proportional limit of steel\n",
-      "\n",
-      "#calculation\n",
-      "\n",
-      "M = (math.pi*E*d**4)/(32*(2*R0+d))      # Bending moment in wire in N-m\n",
-      "print \"Bending moment in the wire is \", round(M,2), \"N-m\"\n",
-      "s_max = (E*d)/(2*R0+d)                  # Maximum bending stress in wire in Pa\n",
-      "print \"Maximum bending stress in the wire is %e\" %(s_max), \"Pa\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Bending moment in the wire is  5.01 N-m\n",
-        "Maximum bending stress in the wire is 7.968127e+08 Pa\n"
-       ]
-      }
-     ],
-     "prompt_number": 10
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.3, page no. 316"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "find maximum tensile and compressive stress in the beam\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "L = 22                          # Span of beam in ft\n",
-      "q = 1.5                         # Uniform load intensity in k/ft\n",
-      "P = 12                          # Concentrated in k\n",
-      "b = 8.75                        # width of cross section of beam in inch\n",
-      "h = 27                          # height of cross section of beam in inch\n",
-      "Ra = 23.59                      # Reaction at point A\n",
-      "Rb = 21.41                      # Reacyion at point B\n",
-      "Mmax = 151.6                    # Maximum bending moment\n",
-      "\n",
-      "#calculation\n",
-      "\n",
-      "S = (b*h**2)/6                  # Section modulus\n",
-      "s = (Mmax*12)/S                 # stress in k\n",
-      "st = s*1000                     # Tensile stress\n",
-      "print \"Maximum tensile stress in the beam\", round(st), \"psi\"\n",
-      "sc = -s*1000                    # Compressive stress\n",
-      "print \"Maximum compressive stress in the beam\", round(sc), \"psi\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum tensile stress in the beam 1711.0 psi\n",
-        "Maximum compressive stress in the beam -1711.0 psi\n"
-       ]
-      }
-     ],
-     "prompt_number": 11
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.4, page no. 318"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "because of uniform load in the beam, calculate maximum tensile & compressive stress\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "q = 3200.0                        # Uniform load intensity in N/m\n",
-      "b = 0.3                           # width of beam in m\n",
-      "h = 0.08                          # Height of the beam in m\n",
-      "t = 0.012                         # thickness of beam in m\n",
-      "Ra = 3600.0                       # Reaction at A in N\n",
-      "Rb = 10800.0                      # Reaction at B in N\n",
-      "Mpos = 2025.0                     # Moment in Nm\n",
-      "Mneg = -3600.0                    # Moment in Nm\n",
-      "\n",
-      "#calculation\n",
-      "y1 = t/2.0\n",
-      "A1 = (b-2*t)*t  \n",
-      "y2 = h/2\n",
-      "A2 = h*t  \n",
-      "A3 = A2  \n",
-      "c1 = ((y1*A1)+(2*y2*A2))/((A1)+(2*A2))\n",
-      "c2 = h - c1 \n",
-      "Ic1 = (b-2*t)*(t**3)*(1.0/12.0)\n",
-      "d1 = c1-(t/2.0)\n",
-      "Iz1 = (Ic1)+(A1*(d1**2))\n",
-      "Iz2 = 956600e-12\n",
-      "Iz3 = Iz2 \n",
-      "Iz = Iz1 + Iz2 + Iz3                # Moment of inertia of the beam cross section\n",
-      "\n",
-      "# Section Modulli\n",
-      "S1 = Iz / c1                        # for the top surface\n",
-      "S2 = Iz / c2                        # for the bottom surface\n",
-      "\n",
-      "# Maximum stresses for the positive section\n",
-      "st = Mpos / S2 \n",
-      "print \"Maximum tensile stress in the beam in positive section is\", st, \"Pa\"\n",
-      "sc = -Mpos / S1 \n",
-      "print \"Maximum compressive stress in the beam in positive section is\", sc, \"Pa\"\n",
-      "\n",
-      "# Maximum stresses for the negative section\n",
-      "snt = -Mneg / S1 \n",
-      "print \"Maximum tensile stress in the beam in negative section is\", snt, \"Pa\"\n",
-      "snc = Mneg / S2 \n",
-      "print \"Maximum compressive stress in the beam in negative section is\", snc, \"Pa\"\n",
-      "\n",
-      "# Conclusion\n",
-      "st_max = st\n",
-      "sc_max = snc"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum tensile stress in the beam in positive section is 50468539.6422 Pa\n",
-        "Maximum compressive stress in the beam in positive section is -15157118.8248 Pa\n",
-        "Maximum tensile stress in the beam in negative section is 26945989.0219 Pa\n",
-        "Maximum compressive stress in the beam in negative section is -89721848.2528 Pa\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Exampe 5.5, page no. 325"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "choose a suitable size for the beam\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "L = 12                      # Length of beam in ft\n",
-      "q = 420                     # Uniform load intensity in lb/ft\n",
-      "s = 1800                    # Allowable bending stress in psi\n",
-      "w = 35                      # weight of wood in lb/ft3\n",
-      "\n",
-      "#calculation\n",
-      "M = (q*L**2*12)/8           # Bending moment in lb-in\n",
-      "S = M/s                     # Section Modulli in in3\n",
-      "\n",
-      "# From Appendix F\n",
-      "q1 = 426.8                  # New uniform load intensity in lb/ft\n",
-      "S1 = S*(q1/q)               # New section modulli in in3\n",
-      "\n",
-      "# From reference to appendix F, a beam of cross section 3*12 inch is selected\n",
-      "print (\"Beam of crosssection 3*12 is sufficient\")"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Beam of crosssection 3*12 is sufficient\n"
-       ]
-      }
-     ],
-     "prompt_number": 6
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.6, page no. 326"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "find min. req. diameter of the woodpost & req. outer diameter of aluminum tube\n",
-      "\"\"\"\n",
-      "\n",
-      "import math\n",
-      "\n",
-      "#initialisation\n",
-      "P = 12000                           # Lataeral load at the upper end in N\n",
-      "h = 2.5                             # Height of post in m\n",
-      "Mmax = P*h                          # Maximum bending moment in Nm\n",
-      "\n",
-      "#calculation\n",
-      "# Part (a) : Wood Post\n",
-      "s1 = 15e06                          # Maximum allowable stress in Pa\n",
-      "S1 = Mmax/s1                        # Section Modulli in m3\n",
-      "d1 = ((32.0*S1)/math.pi)**(1.0/3.0)       # diameter in m\n",
-      "print \"the minimum required diameter d1 of the wood post is\", round(d1,3), \"m\"\n",
-      "\n",
-      "# Part (b) : Alluminium tube\n",
-      "s2 = 50e06                          # Maximum allowable stress in Pa\n",
-      "S2 = Mmax/s2                        # Section Modulli in m3\n",
-      "d2 = (S2/0.06712)**(1.0/3.0)            # diameter in meter.....(1) \n",
-      "print \"minimum required outer diameter d2 of the aluminum tube is\", round(d2,3),\"m\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the minimum required diameter d1 of the wood post is 0.273 m\n",
-        "minimum required outer diameter d2 of the aluminum tube is 0.208 m\n"
-       ]
-      }
-     ],
-     "prompt_number": 18
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.7, page no. 326"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "evaluate and select a structural steel beam of wide-flange shape to support the loads\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "q = 2000.0                        # Uniform load intensity in lb/ft\n",
-      "s = 18000.0                       # Maximum allowable load in Psi\n",
-      "Ra = 18860.0                      # Reaction at point  A\n",
-      "Rb = 17140.0                      # Reaction at point  B\n",
-      "\n",
-      "#calculation\n",
-      "x1 = Ra/q                         # Distance in ft from left end to the point of zero shear\n",
-      "Mmax = (Ra*x1)-((q*(x1**2))/2.0)  # Maximum bending moment in lb-ft\n",
-      "S = (Mmax*12.0)/s                 # Section Modulli in in3\n",
-      "\n",
-      "# Trial Beam\n",
-      "Ra_t = 19380.0                            # Reaction at point  A\n",
-      "Rb_t = 17670.0                            # Reaction at point  B\n",
-      "\n",
-      "#in Python the value for x1 differes by some points and hence the subsequent results differ\n",
-      "x1_t = Ra_t/q                             # Distance in ft from left end to the point of zero shear\n",
-      "Mmax_t = (Ra_t*x1_t)-((q*(x1_t**2))/2.0)  # Maximum bending moment in lb-ft\n",
-      "S_t = (Mmax_t*12.0)/s                     # Section Modulli in in3\n",
-      "# From table E beam 12*50 is selected \n",
-      "print \"Beam of crosssection 12*50 is selected with section modulli\", round(S_t,1), \"in^3\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Beam of crosssection 12*50 is selected with section modulli 62.6 in^3\n"
-       ]
-      }
-     ],
-     "prompt_number": 8
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.8, page 329"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "find min. req. dimension of the posts\n",
-      "\"\"\"\n",
-      "\n",
-      "import math\n",
-      "\n",
-      "#initialisation \n",
-      "g = 9810                        # Specific weight of water in N/m3\n",
-      "h = 2                           # Height of dam in m\n",
-      "s = 0.8                         # Dismath.tance between square cross section in m\n",
-      "sa = 8e06                       # Maximum allowable stress in Pa\n",
-      "\n",
-      "#Calculations\n",
-      "b = ((g*(h**3)*s)/sa)**(1.0/3.0)    # Dimension of croossection in m\n",
-      "\n",
-      "#Result\n",
-      "print \"the minimum required dimension b of the posts\", round(b,3), \"m\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the minimum required dimension b of the posts 0.199 m\n"
-       ]
-      }
-     ],
-     "prompt_number": 15
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.11, page no. 341"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "find normal & shear stress at point C\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "L = 3                       # Span of beam in ft\n",
-      "q = 160                     # Uniform load intensity in lb/in\n",
-      "b = 1                       # Width of cross section\n",
-      "h = 4                       # Height of cross section\n",
-      "\n",
-      "# Calculations from chapter 4\n",
-      "Mc = 17920                  # Bending moment in ld-in\n",
-      "Vc = -1600                  # Loading in lb\n",
-      "I = (b*(h**3))/12.0           # Moment of inertia in in4\n",
-      "sc = -(Mc*1)/I              # Compressive stress at point C in psi\n",
-      "Ac = 1*1                    # Area of section C in inch2\n",
-      "yc = 1.5                    # dismath.tance between midlayers od section C and cross section of beam\n",
-      "Qc = Ac*yc                  # First moment of C cross section in inch3\n",
-      "tc = (Vc*Qc)/(I*b)          # Shear stress in Psi\n",
-      "print \"Normal stress at C\", sc, \"psi\"\n",
-      "print \"Shear stress at C\", tc, \"psi\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Normal stress at C -3360.0 psi\n",
-        "Shear stress at C -450.0 psi\n"
-       ]
-      }
-     ],
-     "prompt_number": 10
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.12, page no. 342"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculate max. permissible value\n",
-      "\"\"\"\n",
-      "\n",
-      "import math\n",
-      "\n",
-      "#initialisation\n",
-      "s = 11e06                       # allowable tensile stress in pa\n",
-      "t = 1.2e06                      # allowable shear stress in pa\n",
-      "b = 0.1                         # Width of cross section in m\n",
-      "h = 0.15                        # Height of cross section in m\n",
-      "a = 0.5                         # in m\n",
-      "\n",
-      "#Calculations\n",
-      "P_bending = (s*b*h**2)/(6.0*a)    # Bending stress in N\n",
-      "P_shear = (2*t*b*h)/3.0           # shear stress in N\n",
-      "Pmax = P_bending                # Because bending stress governs the design\n",
-      "\n",
-      "#Result\n",
-      "print \"the maximum permissible value Pmax of the loads\", Pmax, \"N\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the maximum permissible value Pmax of the loads 8250.0 N\n"
-       ]
-      }
-     ],
-     "prompt_number": 11
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.13, page no. 345"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "evaluate max. shear stress in the pole & diameter of solid pole\n",
-      "\"\"\"\n",
-      "\n",
-      "import math\n",
-      "\n",
-      "#initialisation\n",
-      "d2 = 4                      # Outer diameter in inch\n",
-      "d1 = 3.2                    # Inner diameter in inch\n",
-      "r2 = d2/2                   # Outer radius in inch\n",
-      "r1 = d1/2                   # inner radius in inch\n",
-      "P = 1500                    # Horizontal force in lb\n",
-      "\n",
-      "#calculation\n",
-      "# Part (a)\n",
-      "t_max = ((r2**2+(r2*r1)+r1**2)*4*P)/(3*math.pi*((r2**4)-(r1**4)))  # Mximum shear stress in Psi\n",
-      "print \"Maximum shear stress in the pole is\", round(t_max), \"psi\"\n",
-      "\n",
-      "# Part (b)\n",
-      "d0 = math.sqrt((16*P)/(3*math.pi*t_max))  # Diameter of solid circular cross section in meter\n",
-      "print \"Diameter of solid circular cross section is \", round(d0,2), \"m\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum shear stress in the pole is 658.0 psi\n",
-        "Diameter of solid circular cross section is  1.97 m\n"
-       ]
-      }
-     ],
-     "prompt_number": 20
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.14, page no. 351"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "maximum shear stress, minimum shear stress, and total shear force in the web.\n",
-      "\"\"\"\n",
-      "\n",
-      "import math\n",
-      "\n",
-      "#initialisation\n",
-      "b = 0.165                   # in m\n",
-      "h = 0.320                   # in m\n",
-      "h1 = 0.290                  # in m\n",
-      "t = 0.0075                  #  in m\n",
-      "V = 45000.0                   # Vertical force in N\n",
-      "\n",
-      "#calculation\n",
-      "I = (1.0/12.0)*((b*(h**3))-(b*(h1**3))+(t*(h1**3))) # Moment of inertia of the cros section\n",
-      "t_max = (V/(8.0*I*t))*((b*(h**2))-(b*(h1**2))+(t*(h1**2))) # Maximum shear stress in Pa\n",
-      "t_min = ((V*b)/(8*I*t))*(h**2-h1**2) # Minimum shear stress in Pa\n",
-      "T = ((t*h1)/3.0)*(2*t_max + t_min) # Total shear force in Pa\n",
-      "t_avg = V/(t*h1)  # Average shear stress in Pa\n",
-      "\n",
-      "#Result\n",
-      "print \"Maximum shear stress in the web is\", round(t_max,2), \"Pa\"\n",
-      "print \"Minimum shear stress in the web is\", round(t_min,2), \"Pa\"\n",
-      "print \"Total shear stress in the web is\", round(T,2), \"N\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum shear stress in the web is 20985785.26 Pa\n",
-        "Minimum shear stress in the web is 17359517.46 Pa\n",
-        "Total shear stress in the web is 43015.04 N\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.15, page no. 352"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "find shear stress at top of the web\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "V = 10000                   # Vertical shear force in lb\n",
-      "b = 4                       # in inch\n",
-      "t = 1                       # in inch\n",
-      "h = 8                       # in inch\n",
-      "h1 = 7                      # in inch\n",
-      "\n",
-      "#calculation\n",
-      "A = b*(h-h1) + t*h1                             # Area of cross section \n",
-      "Qaa = ((h+h1)/2.0)*b*(h-h1) + (h1/2.0)*(t*h1)       # First moment of cross section\n",
-      "c2 = Qaa/A                                      # Position of neutral axis in inch\n",
-      "c1 = h-c2                                       # Position of neutral axis in inch\n",
-      "Iaa = (b*h**3)/3.0 - ((b-t)*h1**3)/3.0              # Moment of inertia about the line aa\n",
-      "I = Iaa - A*c2**2                               # Moment of inertia of crosssection\n",
-      "Q1 = b*(h-h1)*(c1-((h-h1)/2.0))                   # First moment of area above the line nn\n",
-      "t1 = (V*Q1)/(I*t)                               # Shear stress at the top of web in Psi\n",
-      "Qmax = (t*c2)*(c2/2.0)                            # Maximum first moment of inertia below neutral axis\n",
-      "t_max = (V*Qmax)/(I*t)                          # Maximum Shear stress in Psi\n",
-      "\n",
-      "#Result\n",
-      "print \"Shear stress at the top of the web is\", round(t1), \"psi\"\n",
-      "print \"Maximum Shear stress in the web is\", round(t_max), \"Psi\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Shear stress at the top of the web is 1462.0 psi\n",
-        "Maximum Shear stress in the web is 1762.0 Psi\n"
-       ]
-      }
-     ],
-     "prompt_number": 24
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.16, page no. 357"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "maximum permissible longitudinal spacing of the screws\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "\n",
-      "Af = 40*180                     # Area of flange in mm2\n",
-      "V = 10500                       # Shear force acting on cross section\n",
-      "F = 800                         # Allowable load in shear\n",
-      "df = 120                        # Dismath.tance between centroid of flange and neutral axis in mm\n",
-      "\n",
-      "#calculation\n",
-      "Q = Af*df                       # First moment of cross section of flange\n",
-      "I = (1.0/12.0)*(210*280**3) - (1.0/12.0)*(180*200**3)  # Moment of inertia of entire cross section in mm4\n",
-      "f = (V*Q)/I                     # Shear flow\n",
-      "s = (2*F)/f                     # Spacing between the screw\n",
-      "\n",
-      "#Result\n",
-      "print \"The maximum permissible longitudinal spacing s of the screws is\", round(s,1), \"mm\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The maximum permissible longitudinal spacing s of the screws is 46.6 mm\n"
-       ]
-      }
-     ],
-     "prompt_number": 25
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.17, page no. 362"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "maximum tensile and compressive stress in the beam\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "L = 60                           # Length of beam in inch\n",
-      "d = 5.5                          # dismath.tance from the point of application of the load P to the longitudinal axis of the tube in inch\n",
-      "b = 6                            # Outer dimension of tube in inch\n",
-      "A = 20                           # Area of cross section of tube in inch\n",
-      "I = 86.67                        # Moment of inertia in in4\n",
-      "P = 1000                         # in lb\n",
-      "theta = 60                       # in degree\n",
-      "Ph = P*math.sin(math.radians(60)) # Horizontal component\n",
-      "Pv = P*math.cos(math.radians(60)) # Vertical component\n",
-      "\n",
-      "#Calculations\n",
-      "M0 = Ph*d                        # Moment in lb-in\n",
-      "y = -3                           # Point at which maximum tensile stress occur in inch\n",
-      "N = Ph                           # Axial force\n",
-      "M = 9870                         # Moment in lb-in\n",
-      "st_max = (N/A)-((M*y)/I)         # Maximum tensile stress in Psi\n",
-      "yc = 3                           # in inch\n",
-      "M1 = 5110                        # moment in lb-in\n",
-      "sc_left = (N/A)-((M*yc)/I)       # Stress at the left of point C in Psi\n",
-      "sc_right = -(M1*yc)/I            # Stress at the right of point C in Psi\n",
-      "sc_max = min(sc_left,sc_right)   # Because both are negative quantities\n",
-      "\n",
-      "#Result\n",
-      "print \"The maximum compressive stress in the beam is\", round(sc_max), \"psi\"\n",
-      "print \"The maximum tensile stress in the beam is\", round(st_max), \"psi\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The maximum compressive stress in the beam is -298.0 psi\n",
-        "The maximum tensile stress in the beam is 385.0 psi\n"
-       ]
-      }
-     ],
-     "prompt_number": 26
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Testing_the_interface/chapter5_3.ipynb b/Testing_the_interface/chapter5_3.ipynb
deleted file mode 100755
index 9042fcb6..00000000
--- a/Testing_the_interface/chapter5_3.ipynb
+++ /dev/null
@@ -1,800 +0,0 @@
-{
- "metadata": {
-  "name": ""
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 5: Stresses in Beams Basic Topics"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.1, page no. 307"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculate radius of curvature, curvature & deflection of beam\n",
-      "\"\"\"\n",
-      "\n",
-      "import math\n",
-      "import numpy\n",
-      "\n",
-      "#initialisation\n",
-      "\n",
-      "L = 8.0                       # length of beam in ft\n",
-      "h = 6.0                       # Height of beam in inch\n",
-      "e = 0.00125                   # elongation on the bottom surface of the beam\n",
-      "y = -3.0                      # Dismath.tance of the bottom surface to the neutral surface of the beam in inch\n",
-      "\n",
-      "#Calculations\n",
-      "r = -(y/e)                    # Radius of curvature\n",
-      "print \"radius of curvature is\", round(r), \"inch\"\n",
-      "k = 1/r                     # curvature in in-1\n",
-      "print \"curvature\", round(k,5), \"ft-1\"\n",
-      "theta = numpy.degrees(numpy.arcsin(((L*12.0)/(2.0*r))))         # angle in degree\n",
-      "print \"Angle of twist\", round(theta,3), \"degree\"\n",
-      "my_del = r*(1-math.cos(math.radians(theta)))       #Deflection in inch\n",
-      "print \"Deflection in the beam is \", round(my_del,4), \"inch\" "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "radius of curvature is 2400.0 inch\n",
-        "curvature 0.00042 ft-1\n",
-        "Angle of twist 1.146 degree\n",
-        "Deflection in the beam is  0.48 inch\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.2, page no. 315"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "Evaluate bending moment & maximum bending stress in the wire\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "d = 0.004                       # thickness of wire in m\n",
-      "R0 = 0.5                        # radius of cylinder in m\n",
-      "E = 200e09                      # Modulus of elasticity of steel\n",
-      "s = 1200e06                     # proportional limit of steel\n",
-      "\n",
-      "#calculation\n",
-      "\n",
-      "M = (math.pi*E*d**4)/(32*(2*R0+d))      # Bending moment in wire in N-m\n",
-      "print \"Bending moment in the wire is \", round(M,2), \"N-m\"\n",
-      "s_max = (E*d)/(2*R0+d)                  # Maximum bending stress in wire in Pa\n",
-      "print \"Maximum bending stress in the wire is %e\" %(s_max), \"Pa\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Bending moment in the wire is  5.01 N-m\n",
-        "Maximum bending stress in the wire is 7.968127e+08 Pa\n"
-       ]
-      }
-     ],
-     "prompt_number": 10
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.3, page no. 316"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "find maximum tensile and compressive stress in the beam\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "L = 22                          # Span of beam in ft\n",
-      "q = 1.5                         # Uniform load intensity in k/ft\n",
-      "P = 12                          # Concentrated in k\n",
-      "b = 8.75                        # width of cross section of beam in inch\n",
-      "h = 27                          # height of cross section of beam in inch\n",
-      "Ra = 23.59                      # Reaction at point A\n",
-      "Rb = 21.41                      # Reacyion at point B\n",
-      "Mmax = 151.6                    # Maximum bending moment\n",
-      "\n",
-      "#calculation\n",
-      "\n",
-      "S = (b*h**2)/6                  # Section modulus\n",
-      "s = (Mmax*12)/S                 # stress in k\n",
-      "st = s*1000                     # Tensile stress\n",
-      "print \"Maximum tensile stress in the beam\", round(st), \"psi\"\n",
-      "sc = -s*1000                    # Compressive stress\n",
-      "print \"Maximum compressive stress in the beam\", round(sc), \"psi\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum tensile stress in the beam 1711.0 psi\n",
-        "Maximum compressive stress in the beam -1711.0 psi\n"
-       ]
-      }
-     ],
-     "prompt_number": 11
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.4, page no. 318"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "because of uniform load in the beam, calculate maximum tensile & compressive stress\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "q = 3200.0                        # Uniform load intensity in N/m\n",
-      "b = 0.3                           # width of beam in m\n",
-      "h = 0.08                          # Height of the beam in m\n",
-      "t = 0.012                         # thickness of beam in m\n",
-      "Ra = 3600.0                       # Reaction at A in N\n",
-      "Rb = 10800.0                      # Reaction at B in N\n",
-      "Mpos = 2025.0                     # Moment in Nm\n",
-      "Mneg = -3600.0                    # Moment in Nm\n",
-      "\n",
-      "#calculation\n",
-      "y1 = t/2.0\n",
-      "A1 = (b-2*t)*t  \n",
-      "y2 = h/2\n",
-      "A2 = h*t  \n",
-      "A3 = A2  \n",
-      "c1 = ((y1*A1)+(2*y2*A2))/((A1)+(2*A2))\n",
-      "c2 = h - c1 \n",
-      "Ic1 = (b-2*t)*(t**3)*(1.0/12.0)\n",
-      "d1 = c1-(t/2.0)\n",
-      "Iz1 = (Ic1)+(A1*(d1**2))\n",
-      "Iz2 = 956600e-12\n",
-      "Iz3 = Iz2 \n",
-      "Iz = Iz1 + Iz2 + Iz3                # Moment of inertia of the beam cross section\n",
-      "\n",
-      "# Section Modulli\n",
-      "S1 = Iz / c1                        # for the top surface\n",
-      "S2 = Iz / c2                        # for the bottom surface\n",
-      "\n",
-      "# Maximum stresses for the positive section\n",
-      "st = Mpos / S2 \n",
-      "print \"Maximum tensile stress in the beam in positive section is\", st, \"Pa\"\n",
-      "sc = -Mpos / S1 \n",
-      "print \"Maximum compressive stress in the beam in positive section is\", sc, \"Pa\"\n",
-      "\n",
-      "# Maximum stresses for the negative section\n",
-      "snt = -Mneg / S1 \n",
-      "print \"Maximum tensile stress in the beam in negative section is\", snt, \"Pa\"\n",
-      "snc = Mneg / S2 \n",
-      "print \"Maximum compressive stress in the beam in negative section is\", snc, \"Pa\"\n",
-      "\n",
-      "# Conclusion\n",
-      "st_max = st\n",
-      "sc_max = snc"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum tensile stress in the beam in positive section is 50468539.6422 Pa\n",
-        "Maximum compressive stress in the beam in positive section is -15157118.8248 Pa\n",
-        "Maximum tensile stress in the beam in negative section is 26945989.0219 Pa\n",
-        "Maximum compressive stress in the beam in negative section is -89721848.2528 Pa\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Exampe 5.5, page no. 325"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "choose a suitable size for the beam\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "L = 12                      # Length of beam in ft\n",
-      "q = 420                     # Uniform load intensity in lb/ft\n",
-      "s = 1800                    # Allowable bending stress in psi\n",
-      "w = 35                      # weight of wood in lb/ft3\n",
-      "\n",
-      "#calculation\n",
-      "M = (q*L**2*12)/8           # Bending moment in lb-in\n",
-      "S = M/s                     # Section Modulli in in3\n",
-      "\n",
-      "# From Appendix F\n",
-      "q1 = 426.8                  # New uniform load intensity in lb/ft\n",
-      "S1 = S*(q1/q)               # New section modulli in in3\n",
-      "\n",
-      "# From reference to appendix F, a beam of cross section 3*12 inch is selected\n",
-      "print (\"Beam of crosssection 3*12 is sufficient\")"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Beam of crosssection 3*12 is sufficient\n"
-       ]
-      }
-     ],
-     "prompt_number": 6
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.6, page no. 326"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "find min. req. diameter of the woodpost & req. outer diameter of aluminum tube\n",
-      "\"\"\"\n",
-      "\n",
-      "import math\n",
-      "\n",
-      "#initialisation\n",
-      "P = 12000                           # Lataeral load at the upper end in N\n",
-      "h = 2.5                             # Height of post in m\n",
-      "Mmax = P*h                          # Maximum bending moment in Nm\n",
-      "\n",
-      "#calculation\n",
-      "# Part (a) : Wood Post\n",
-      "s1 = 15e06                          # Maximum allowable stress in Pa\n",
-      "S1 = Mmax/s1                        # Section Modulli in m3\n",
-      "d1 = ((32.0*S1)/math.pi)**(1.0/3.0)       # diameter in m\n",
-      "print \"the minimum required diameter d1 of the wood post is\", round(d1,3), \"m\"\n",
-      "\n",
-      "# Part (b) : Alluminium tube\n",
-      "s2 = 50e06                          # Maximum allowable stress in Pa\n",
-      "S2 = Mmax/s2                        # Section Modulli in m3\n",
-      "d2 = (S2/0.06712)**(1.0/3.0)            # diameter in meter.....(1) \n",
-      "print \"minimum required outer diameter d2 of the aluminum tube is\", round(d2,3),\"m\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the minimum required diameter d1 of the wood post is 0.273 m\n",
-        "minimum required outer diameter d2 of the aluminum tube is 0.208 m\n"
-       ]
-      }
-     ],
-     "prompt_number": 18
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.7, page no. 326"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "evaluate and select a structural steel beam of wide-flange shape to support the loads\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "q = 2000.0                        # Uniform load intensity in lb/ft\n",
-      "s = 18000.0                       # Maximum allowable load in Psi\n",
-      "Ra = 18860.0                      # Reaction at point  A\n",
-      "Rb = 17140.0                      # Reaction at point  B\n",
-      "\n",
-      "#calculation\n",
-      "x1 = Ra/q                         # Distance in ft from left end to the point of zero shear\n",
-      "Mmax = (Ra*x1)-((q*(x1**2))/2.0)  # Maximum bending moment in lb-ft\n",
-      "S = (Mmax*12.0)/s                 # Section Modulli in in3\n",
-      "\n",
-      "# Trial Beam\n",
-      "Ra_t = 19380.0                            # Reaction at point  A\n",
-      "Rb_t = 17670.0                            # Reaction at point  B\n",
-      "\n",
-      "#in Python the value for x1 differes by some points and hence the subsequent results differ\n",
-      "x1_t = Ra_t/q                             # Distance in ft from left end to the point of zero shear\n",
-      "Mmax_t = (Ra_t*x1_t)-((q*(x1_t**2))/2.0)  # Maximum bending moment in lb-ft\n",
-      "S_t = (Mmax_t*12.0)/s                     # Section Modulli in in3\n",
-      "# From table E beam 12*50 is selected \n",
-      "print \"Beam of crosssection 12*50 is selected with section modulli\", round(S_t,1), \"in^3\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Beam of crosssection 12*50 is selected with section modulli 62.6 in^3\n"
-       ]
-      }
-     ],
-     "prompt_number": 8
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.8, page 329"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "find min. req. dimension of the posts\n",
-      "\"\"\"\n",
-      "\n",
-      "import math\n",
-      "\n",
-      "#initialisation \n",
-      "g = 9810                        # Specific weight of water in N/m3\n",
-      "h = 2                           # Height of dam in m\n",
-      "s = 0.8                         # Dismath.tance between square cross section in m\n",
-      "sa = 8e06                       # Maximum allowable stress in Pa\n",
-      "\n",
-      "#Calculations\n",
-      "b = ((g*(h**3)*s)/sa)**(1.0/3.0)    # Dimension of croossection in m\n",
-      "\n",
-      "#Result\n",
-      "print \"the minimum required dimension b of the posts\", round(b,3), \"m\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the minimum required dimension b of the posts 0.199 m\n"
-       ]
-      }
-     ],
-     "prompt_number": 15
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.11, page no. 341"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "find normal & shear stress at point C\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "L = 3                       # Span of beam in ft\n",
-      "q = 160                     # Uniform load intensity in lb/in\n",
-      "b = 1                       # Width of cross section\n",
-      "h = 4                       # Height of cross section\n",
-      "\n",
-      "# Calculations from chapter 4\n",
-      "Mc = 17920                  # Bending moment in ld-in\n",
-      "Vc = -1600                  # Loading in lb\n",
-      "I = (b*(h**3))/12.0           # Moment of inertia in in4\n",
-      "sc = -(Mc*1)/I              # Compressive stress at point C in psi\n",
-      "Ac = 1*1                    # Area of section C in inch2\n",
-      "yc = 1.5                    # dismath.tance between midlayers od section C and cross section of beam\n",
-      "Qc = Ac*yc                  # First moment of C cross section in inch3\n",
-      "tc = (Vc*Qc)/(I*b)          # Shear stress in Psi\n",
-      "print \"Normal stress at C\", sc, \"psi\"\n",
-      "print \"Shear stress at C\", tc, \"psi\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Normal stress at C -3360.0 psi\n",
-        "Shear stress at C -450.0 psi\n"
-       ]
-      }
-     ],
-     "prompt_number": 10
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.12, page no. 342"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculate max. permissible value\n",
-      "\"\"\"\n",
-      "\n",
-      "import math\n",
-      "\n",
-      "#initialisation\n",
-      "s = 11e06                       # allowable tensile stress in pa\n",
-      "t = 1.2e06                      # allowable shear stress in pa\n",
-      "b = 0.1                         # Width of cross section in m\n",
-      "h = 0.15                        # Height of cross section in m\n",
-      "a = 0.5                         # in m\n",
-      "\n",
-      "#Calculations\n",
-      "P_bending = (s*b*h**2)/(6.0*a)    # Bending stress in N\n",
-      "P_shear = (2*t*b*h)/3.0           # shear stress in N\n",
-      "Pmax = P_bending                # Because bending stress governs the design\n",
-      "\n",
-      "#Result\n",
-      "print \"the maximum permissible value Pmax of the loads\", Pmax, \"N\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the maximum permissible value Pmax of the loads 8250.0 N\n"
-       ]
-      }
-     ],
-     "prompt_number": 11
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.13, page no. 345"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "evaluate max. shear stress in the pole & diameter of solid pole\n",
-      "\"\"\"\n",
-      "\n",
-      "import math\n",
-      "\n",
-      "#initialisation\n",
-      "d2 = 4                      # Outer diameter in inch\n",
-      "d1 = 3.2                    # Inner diameter in inch\n",
-      "r2 = d2/2                   # Outer radius in inch\n",
-      "r1 = d1/2                   # inner radius in inch\n",
-      "P = 1500                    # Horizontal force in lb\n",
-      "\n",
-      "#calculation\n",
-      "# Part (a)\n",
-      "t_max = ((r2**2+(r2*r1)+r1**2)*4*P)/(3*math.pi*((r2**4)-(r1**4)))  # Mximum shear stress in Psi\n",
-      "print \"Maximum shear stress in the pole is\", round(t_max), \"psi\"\n",
-      "\n",
-      "# Part (b)\n",
-      "d0 = math.sqrt((16*P)/(3*math.pi*t_max))  # Diameter of solid circular cross section in meter\n",
-      "print \"Diameter of solid circular cross section is \", round(d0,2), \"m\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum shear stress in the pole is 658.0 psi\n",
-        "Diameter of solid circular cross section is  1.97 m\n"
-       ]
-      }
-     ],
-     "prompt_number": 20
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.14, page no. 351"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "maximum shear stress, minimum shear stress, and total shear force in the web.\n",
-      "\"\"\"\n",
-      "\n",
-      "import math\n",
-      "\n",
-      "#initialisation\n",
-      "b = 0.165                   # in m\n",
-      "h = 0.320                   # in m\n",
-      "h1 = 0.290                  # in m\n",
-      "t = 0.0075                  #  in m\n",
-      "V = 45000.0                   # Vertical force in N\n",
-      "\n",
-      "#calculation\n",
-      "I = (1.0/12.0)*((b*(h**3))-(b*(h1**3))+(t*(h1**3))) # Moment of inertia of the cros section\n",
-      "t_max = (V/(8.0*I*t))*((b*(h**2))-(b*(h1**2))+(t*(h1**2))) # Maximum shear stress in Pa\n",
-      "t_min = ((V*b)/(8*I*t))*(h**2-h1**2) # Minimum shear stress in Pa\n",
-      "T = ((t*h1)/3.0)*(2*t_max + t_min) # Total shear force in Pa\n",
-      "t_avg = V/(t*h1)  # Average shear stress in Pa\n",
-      "\n",
-      "#Result\n",
-      "print \"Maximum shear stress in the web is\", round(t_max,2), \"Pa\"\n",
-      "print \"Minimum shear stress in the web is\", round(t_min,2), \"Pa\"\n",
-      "print \"Total shear stress in the web is\", round(T,2), \"N\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum shear stress in the web is 20985785.26 Pa\n",
-        "Minimum shear stress in the web is 17359517.46 Pa\n",
-        "Total shear stress in the web is 43015.04 N\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.15, page no. 352"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "find shear stress at top of the web\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "V = 10000                   # Vertical shear force in lb\n",
-      "b = 4                       # in inch\n",
-      "t = 1                       # in inch\n",
-      "h = 8                       # in inch\n",
-      "h1 = 7                      # in inch\n",
-      "\n",
-      "#calculation\n",
-      "A = b*(h-h1) + t*h1                             # Area of cross section \n",
-      "Qaa = ((h+h1)/2.0)*b*(h-h1) + (h1/2.0)*(t*h1)       # First moment of cross section\n",
-      "c2 = Qaa/A                                      # Position of neutral axis in inch\n",
-      "c1 = h-c2                                       # Position of neutral axis in inch\n",
-      "Iaa = (b*h**3)/3.0 - ((b-t)*h1**3)/3.0              # Moment of inertia about the line aa\n",
-      "I = Iaa - A*c2**2                               # Moment of inertia of crosssection\n",
-      "Q1 = b*(h-h1)*(c1-((h-h1)/2.0))                   # First moment of area above the line nn\n",
-      "t1 = (V*Q1)/(I*t)                               # Shear stress at the top of web in Psi\n",
-      "Qmax = (t*c2)*(c2/2.0)                            # Maximum first moment of inertia below neutral axis\n",
-      "t_max = (V*Qmax)/(I*t)                          # Maximum Shear stress in Psi\n",
-      "\n",
-      "#Result\n",
-      "print \"Shear stress at the top of the web is\", round(t1), \"psi\"\n",
-      "print \"Maximum Shear stress in the web is\", round(t_max), \"Psi\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Shear stress at the top of the web is 1462.0 psi\n",
-        "Maximum Shear stress in the web is 1762.0 Psi\n"
-       ]
-      }
-     ],
-     "prompt_number": 24
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.16, page no. 357"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "maximum permissible longitudinal spacing of the screws\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "\n",
-      "Af = 40*180                     # Area of flange in mm2\n",
-      "V = 10500                       # Shear force acting on cross section\n",
-      "F = 800                         # Allowable load in shear\n",
-      "df = 120                        # Dismath.tance between centroid of flange and neutral axis in mm\n",
-      "\n",
-      "#calculation\n",
-      "Q = Af*df                       # First moment of cross section of flange\n",
-      "I = (1.0/12.0)*(210*280**3) - (1.0/12.0)*(180*200**3)  # Moment of inertia of entire cross section in mm4\n",
-      "f = (V*Q)/I                     # Shear flow\n",
-      "s = (2*F)/f                     # Spacing between the screw\n",
-      "\n",
-      "#Result\n",
-      "print \"The maximum permissible longitudinal spacing s of the screws is\", round(s,1), \"mm\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The maximum permissible longitudinal spacing s of the screws is 46.6 mm\n"
-       ]
-      }
-     ],
-     "prompt_number": 25
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.17, page no. 362"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "maximum tensile and compressive stress in the beam\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "L = 60                           # Length of beam in inch\n",
-      "d = 5.5                          # dismath.tance from the point of application of the load P to the longitudinal axis of the tube in inch\n",
-      "b = 6                            # Outer dimension of tube in inch\n",
-      "A = 20                           # Area of cross section of tube in inch\n",
-      "I = 86.67                        # Moment of inertia in in4\n",
-      "P = 1000                         # in lb\n",
-      "theta = 60                       # in degree\n",
-      "Ph = P*math.sin(math.radians(60)) # Horizontal component\n",
-      "Pv = P*math.cos(math.radians(60)) # Vertical component\n",
-      "\n",
-      "#Calculations\n",
-      "M0 = Ph*d                        # Moment in lb-in\n",
-      "y = -3                           # Point at which maximum tensile stress occur in inch\n",
-      "N = Ph                           # Axial force\n",
-      "M = 9870                         # Moment in lb-in\n",
-      "st_max = (N/A)-((M*y)/I)         # Maximum tensile stress in Psi\n",
-      "yc = 3                           # in inch\n",
-      "M1 = 5110                        # moment in lb-in\n",
-      "sc_left = (N/A)-((M*yc)/I)       # Stress at the left of point C in Psi\n",
-      "sc_right = -(M1*yc)/I            # Stress at the right of point C in Psi\n",
-      "sc_max = min(sc_left,sc_right)   # Because both are negative quantities\n",
-      "\n",
-      "#Result\n",
-      "print \"The maximum compressive stress in the beam is\", round(sc_max), \"psi\"\n",
-      "print \"The maximum tensile stress in the beam is\", round(st_max), \"psi\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The maximum compressive stress in the beam is -298.0 psi\n",
-        "The maximum tensile stress in the beam is 385.0 psi\n"
-       ]
-      }
-     ],
-     "prompt_number": 26
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Testing_the_interface/chapter6.ipynb b/Testing_the_interface/chapter6.ipynb
deleted file mode 100755
index 344830c9..00000000
--- a/Testing_the_interface/chapter6.ipynb
+++ /dev/null
@@ -1,444 +0,0 @@
-{
- "metadata": {
-  "name": ""
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 6: Stresses in Beams Advanced Topics"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 6.1, page no. 400"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "largest tensile and compressive stresses in the wood & the max. and min. tensile stresses in the steel\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "# 4*6 inch wood beam dimension\n",
-      "# 4*0.5 inch steel beam dimension\n",
-      "M = 60.0                          # Moment in k-in\n",
-      "E1 = 1500.                       # in Ksi\n",
-      "E2 = 30000.0                      # in Ksi\n",
-      "h1 = 5.031                      # Distance between top surface and neutral axis of the beam in inch by solving 1500*(h1-3)*24 + 30000*(h1-6.25)*2 = 0\n",
-      "\n",
-      "#calculation\n",
-      "h2 = 6.5 - h1 \n",
-      "I1 = (1.0/12.0)*(4*6**3) + (4*6)*(h1-3)**2              # Momeny of inertia of the wooden cross section\n",
-      "I2 = (1.0/12.0)*(4*0.5**3) + (4*0.5)*(h2-0.25)**2       # Momeny of inertia of the steel cross section\n",
-      "I = I1 + I2                                             # Moment of inertia of whole cross section\n",
-      "\n",
-      "# Material 1\n",
-      "s1a = -(M*h1*E1)/((E1*I1)+(E2*I2))                      # Maximum compressive stress in ksi where y = h1\n",
-      "s1c = -(M*(-(h2-0.5))*E1)/((E1*I1)+(E2*I2))             # Maximum tensile stress in ksi where y = -(h2-0.5)\n",
-      "print \"Maximum compressive stress in wood is\", round(s1a,3)*1000, \"psi\"\n",
-      "print \"Maximum tensile stress in wood is\", round(s1c,3)*1000, \"psi\"\n",
-      "\n",
-      "# Material 2\n",
-      "s2a = -(M*(-h2)*E2)/((E1*I1)+(E2*I2))                   # Maximum tensile stress in ksi where y = -h2\n",
-      "s2c = -(M*(-(h2-0.5))*E2)/((E1*I1)+(E2*I2))             # Minimum tensile stress in ksi where y = -(h2-0.5)\n",
-      "print \"Maximum tensile stress in steel is\", round(s2a,3)*1000, \"psi\"\n",
-      "print \"Minimum tensile stress in steel is\", round(s2c,3)*1000, \"psi\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum compressive stress in wood is -1305.0 psi\n",
-        "Maximum tensile stress in wood is 251.0 psi\n",
-        "Maximum tensile stress in steel is 7622.0 psi\n",
-        "Minimum tensile stress in steel is 5028.0 psi\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 6.2, page no. 402"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "maximum tensile and compressive stresses in the faces and the core using: general theory for composite beams and \n",
-      "approximate theory for sandwich beams\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "\n",
-      "M = 3000                        # moment in N-m\n",
-      "t = 0.005                       # thickness of alluminiun in m\n",
-      "E1 = 72e09                      # Modulus of elasticity of alluminium in Pa\n",
-      "E2 = 800e06                     # Modulus of elasticity of Plastic core in Pa\n",
-      "b = 0.2                         # Width of cross section in m\n",
-      "h = 0.160                       # Height of cross section in m\n",
-      "hc = 0.150                      # Height of Plastic core cross section in m\n",
-      "\n",
-      "#calculation\n",
-      "I1 = (b/12.0)*(h**3 - hc**3)    # Moment of inertia of alluminium cross section\n",
-      "I2 = (b/12.0)*(hc**3)           # Moment of inertia of Plastic core cross section\n",
-      "f = (E1*I1) + (E2*I2)           # Flexural rigidity of the cross section\n",
-      "s1_max = (M*(h/2.0)*E1)/f \n",
-      "s1c = -s1_max                   # Maximum compressive stress in alluminium core in Pa\n",
-      "s1t = s1_max                    # Maximum tensile stress in alluminium core in Pa\n",
-      "print \"Maximum compressive stress on alluminium face by the general theory for composite beams is\", s1c, \"Pa\"\n",
-      "print \"Maximum tensile stress on alluminium face by the general theory for composite beams is\", s1t, \"Pa\"\n",
-      "s2_max = (M*(hc/2.0)*E2)/f \n",
-      "s2c = -s2_max                   # Maximum compressive stress in Plastic core in Pa\n",
-      "s2t = s2_max                    # Maximum tensile stress in Plastic core in Pa\n",
-      "print \"Maximum compressive stress in plastic core by the general theory for composite beams is\", s2c, \"Pa\"\n",
-      "print \"Maximum tensile stress in plastic core by the general theory for composite beams is\", s2t, \"Pa\"\n",
-      "\n",
-      "# Part (b) : Calculation from approximate theory of sandwitch\n",
-      "s1_max1 = (M*h)/(2*I1) \n",
-      "s1c1 = -s1_max1                 # Maximum compressive stress in alluminium core in Pa\n",
-      "s1t1 = s1_max1                  # Maximum tensile stress in alluminium core in Pa\n",
-      "print \"Maximum compressive stress on alluminium core by approximate theory of sandwitch is\", s1c1, \"Pa\"\n",
-      "print \"Maximum tensile stress on alluminium core by approximate theory of sandwitch is\", s1t1, \"Pa\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum compressive stress on alluminium face by the general theory for composite beams is -18984838.497 Pa\n",
-        "Maximum tensile stress on alluminium face by the general theory for composite beams is 18984838.497 Pa\n",
-        "Maximum compressive stress in plastic core by the general theory for composite beams is -197758.734344 Pa\n",
-        "Maximum tensile stress in plastic core by the general theory for composite beams is 197758.734344 Pa\n",
-        "Maximum compressive stress on alluminium core by approximate theory of sandwitch is -19972260.749 Pa\n",
-        "Maximum tensile stress on alluminium core by approximate theory of sandwitch is 19972260.749 Pa\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 6.3, page no. 407"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculate largest tensile & compressive stresses in the wood\n",
-      "also, the maximum and minimum tensile stresses in the steel\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "# 4*6 inch wood beam dimension\n",
-      "# 4*0.5 inch steel beam dimension\n",
-      "M = 60.0                      # Moment in k-in\n",
-      "E1 = 1500.0                   # in Ksi\n",
-      "E2 = 30000.0                  # in Ksi\n",
-      "b = 4.0                       # width of crosssection in inch\n",
-      "\n",
-      "#calculation\n",
-      "# Transformed Section\n",
-      "n = E2/E1                   # Modular ratio\n",
-      "b1 = n*4                    # Increased width of transformed cross section\n",
-      "\n",
-      "# Neutral axis\n",
-      "h1 = ((3*4*6)+(80*0.5*6.25))/((4*6)+(80*0.5)) # Dismath.tance between top surface and neutral axis of the beam in inch\n",
-      "h2 = 6.5 - h1  # in inch\n",
-      "\n",
-      "# Moment of inertia\n",
-      "It = (1.0/12.0)*(4*6**3) + (4*6)*(h1-3)**2 + (1.0/12.0)*(80*0.5**3) + (80*0.5)*(h2-0.25)**2  # Moment of inertia of transformed cross section\n",
-      "\n",
-      "# Material 1\n",
-      "s1a = -(M*h1)/It  # Maximum tensile stress in ksi where y = h1\n",
-      "s1c = -(M*(-(h2-0.5)))/It  # Maximum compressive stress in ksi where y = -(h2-0.5)\n",
-      "print \"Maximum tensile stress in wood is\", s1a*1000, \"psi\"\n",
-      "print \"Maximum compressive stress in wood is\", s1c*1000, \"psi\"\n",
-      "\n",
-      "# Material 2\n",
-      "s2a = -(M*(-h2)*n)/It  # Maximum tensile stress in ksi where y = -h2\n",
-      "s2c = -(M*(-(h2-0.5)*n))/It  # Minimum tensile stress in ksi where y = -(h2-0.5)\n",
-      "print \"Maximum tensile stress in steel\", s2a*1000, \"psi\"\n",
-      "print \"Minimum tensile stress in steel\", s2c*1000, \"psi\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum tensile stress in wood is -1305.28781191 psi\n",
-        "Maximum compressive stress in wood is 251.328709125 psi\n",
-        "Maximum tensile stress in steel 7620.9350509 psi\n",
-        "Minimum tensile stress in steel 5026.57418251 psi\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 6.4,page no. 412"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "maximum tensile and compressive stresses in the beam\n",
-      "\"\"\"\n",
-      "\n",
-      "import math\n",
-      "import numpy\n",
-      "\n",
-      "#initialisation\n",
-      "\n",
-      "q = 3000.0                    # Uniform load intensity in N/m\n",
-      "a = 26.57                   # tilt of the beam in degree\n",
-      "b = 0.1                     # width of the beam\n",
-      "h = 0.15                    # height of the beam\n",
-      "L = 1.6                     # Span of the beam\n",
-      "\n",
-      "#calculation\n",
-      "qy = q*math.cos(math.radians(a))  # Component of q in y direction\n",
-      "qz = q*math.sin(math.radians(a))  # Component of q in z direction\n",
-      "My = (qz*L**2.0)/8.0                      # Maximum bending moment in y direction\n",
-      "Mz = (qy*L**2.0)/8.0                      # Maximum bending moment in z direction\n",
-      "Iy = (h*b**3.0)/12.0                      # Moment of inertia along y\n",
-      "Iz = (b*h**3.0)/12.0                      # Moment of inertia alon z\n",
-      "s = ((3*q*L**2)/(4*b*h))*((math.sin(math.radians(a))/b)+(math.cos(math.radians(a))/h))\n",
-      "sc = -s  # Maximum compressive stress\n",
-      "st = s # Maximum tensile stress\n",
-      "print \"Maximum compressive stress in the beam is\", sc, \"Pa\"\n",
-      "print \"Maximum tensile stress in the beam is\", st, \"Pa\"\n",
-      "\n",
-      "# Neutral axis\n",
-      "l = (h/b)**2\n",
-      "t = math.sin(math.radians(a)/math.cos(math.radians(a)))\n",
-      "j = l*(math.sin(math.radians(a)/math.cos(math.radians(a))))\n",
-      "be = math.degrees((numpy.arctan((j))))  # Inclination of Neutral axis to z axis\n",
-      "print \"Inclination of Neutral axis to z axis is\", round(be,2), \"degree\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum compressive stress in the beam is -4007231.57248 Pa\n",
-        "Maximum tensile stress in the beam is 4007231.57248 Pa\n",
-        "Inclination of Neutral axis to z axis is 48.11 degree\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 6.5, page no. 414"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "maximum bending stresses in the beam for various conditions\n",
-      "\"\"\"\n",
-      "\n",
-      "import math\n",
-      "import numpy \n",
-      "\n",
-      "#initialisation\n",
-      "L = 12.0                          # Length of the beam in ft\n",
-      "P = 10.0                          # Load in k acting in vertical direction\n",
-      "\n",
-      "#Part (a)\n",
-      "h = 24.0                          # Height of beam in inch\n",
-      "Iz = 2100                         # Moment of inertia along z axis in in4\n",
-      "Iy = 42.2                         # Moment of inertia along y axis in in4\n",
-      "\n",
-      "#calculation\n",
-      "s_max = (P*(h/2.0)*L*12)/Iz       # Maximum stress in Ksi\n",
-      "print \"Maximum tensile stress in the beam at the top of the beam\", round(s_max*1000), \"psi\"\n",
-      "print \"Maximum compressive stress in the beam at the bottom of the beam\", round(-s_max*1000), \"psi\"\n",
-      "\n",
-      "#Part (b)\n",
-      "a = 1                                     # Angle between y axis and the load\n",
-      "My = -(P*math.sin(math.radians(a)))*L*12  # Moment along y-axis in K-in\n",
-      "Mz = -(P*math.cos(math.radians(a)))*L*12  # Moment along z-axis in K-in\n",
-      "ba = math.radians(numpy.arctan(((My*Iz)/(Mz*Iy)))) # Orientation of neutral axis\n",
-      "z = -3.5\n",
-      "y = 12.0                                  # Coordinates of the point A and B where maximum stress occur\n",
-      "s = ((My*z)/Iy)-((Mz*y)/Iz)               # Stress in Ksi\n",
-      "sa = s                                    # Tensile stress at A\n",
-      "sb = -s                                   # Compressive stress in B\n",
-      "print \"The tensile stress at A is\", round(sa*1000), \"psi\"\n",
-      "print \"The compressive stress at B is\", round(sb*1000), \"psi\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum tensile stress in the beam at the top of the beam 8229.0 psi\n",
-        "Maximum compressive stress in the beam at the bottom of the beam -8229.0 psi\n",
-        "The tensile stress at A is 10312.0 psi\n",
-        "The compressive stress at B is -10312.0 psi\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 6.6, page no. 420"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "the bending stresses at points A and B\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "import numpy\n",
-      "\n",
-      "#initialisation\n",
-      "M = 15                              # Bending moment in k-in\n",
-      "t = 10                              # Angle between line of action of moment and z-axis\n",
-      "\n",
-      "# Properties of cross section\n",
-      "c = 0.634                            # Location of centroid on the axis of symmetry\n",
-      "Iy = 2.28                            # Moment of inertia in y-direction in in4\n",
-      "Iz = 67.4                            # Moment of inertia in z-direction in in4\n",
-      "ya = 5\n",
-      "za = -2.6+0.634              # Coordinates of point A\n",
-      "yb = -5\n",
-      "zb = 0.634                  # Coordinates of point B\n",
-      "My = M*math.sin(math.radians(t))     # Moment along y-axis\n",
-      "Mz = M*math.cos(math.radians(t))     # Moment along z-axis\n",
-      "sa = ((My*za)/Iy)-((Mz*ya)/Iz)       # Bending stress at point A in ksi\n",
-      "sb = ((My*zb)/Iy)-((Mz*yb)/Iz)       # Bending stress at point B in ksi\n",
-      "print \"The bending stress at point A is\", round(sa*1000), \"psi\"\n",
-      "print \"The bending stress at point B is\", round(sb*1000), \"psi\"\n",
-      "\n",
-      "# Neutral axis\n",
-      "j = (Iz/Iy)*(math.sin(math.radians(t)/math.cos(math.radians(t))))\n",
-      "be = numpy.degrees(numpy.arctan((j)))        # Inclination of neutral axis to z-axis in degree\n",
-      "print \"Inclination of neutral axis to z-axis is\", round(be,1), \"degree\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The bending stress at point A is -3342.0 psi\n",
-        "The bending stress at point B is 1820.0 psi\n",
-        "Inclination of neutral axis to z-axis is 79.1 degree\n"
-       ]
-      }
-     ],
-     "prompt_number": 16
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 6.9, page no. 448"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculate magnitude of the moment M\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialization\n",
-      "b = 5                   # in inch\n",
-      "b1 = 4                  # in inch\n",
-      "h = 9                   # in inch\n",
-      "h1 = 7.5                # in inch\n",
-      "sy = 33                 # stress along y axis in ksi\n",
-      "\n",
-      "#Calculations\n",
-      "M = (sy/12.0)*((3*b*h**2)-(b+(2*b1))*(h1**2))  # Bending moment acting in k-in\n",
-      "\n",
-      "#Result\n",
-      "print \"the magnitude of the moment M is\", round(M), \"k-in\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the magnitude of the moment M is 1330.0 k-in\n"
-       ]
-      }
-     ],
-     "prompt_number": 7
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Testing_the_interface/chapter6_1.ipynb b/Testing_the_interface/chapter6_1.ipynb
deleted file mode 100755
index 344830c9..00000000
--- a/Testing_the_interface/chapter6_1.ipynb
+++ /dev/null
@@ -1,444 +0,0 @@
-{
- "metadata": {
-  "name": ""
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 6: Stresses in Beams Advanced Topics"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 6.1, page no. 400"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "largest tensile and compressive stresses in the wood & the max. and min. tensile stresses in the steel\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "# 4*6 inch wood beam dimension\n",
-      "# 4*0.5 inch steel beam dimension\n",
-      "M = 60.0                          # Moment in k-in\n",
-      "E1 = 1500.                       # in Ksi\n",
-      "E2 = 30000.0                      # in Ksi\n",
-      "h1 = 5.031                      # Distance between top surface and neutral axis of the beam in inch by solving 1500*(h1-3)*24 + 30000*(h1-6.25)*2 = 0\n",
-      "\n",
-      "#calculation\n",
-      "h2 = 6.5 - h1 \n",
-      "I1 = (1.0/12.0)*(4*6**3) + (4*6)*(h1-3)**2              # Momeny of inertia of the wooden cross section\n",
-      "I2 = (1.0/12.0)*(4*0.5**3) + (4*0.5)*(h2-0.25)**2       # Momeny of inertia of the steel cross section\n",
-      "I = I1 + I2                                             # Moment of inertia of whole cross section\n",
-      "\n",
-      "# Material 1\n",
-      "s1a = -(M*h1*E1)/((E1*I1)+(E2*I2))                      # Maximum compressive stress in ksi where y = h1\n",
-      "s1c = -(M*(-(h2-0.5))*E1)/((E1*I1)+(E2*I2))             # Maximum tensile stress in ksi where y = -(h2-0.5)\n",
-      "print \"Maximum compressive stress in wood is\", round(s1a,3)*1000, \"psi\"\n",
-      "print \"Maximum tensile stress in wood is\", round(s1c,3)*1000, \"psi\"\n",
-      "\n",
-      "# Material 2\n",
-      "s2a = -(M*(-h2)*E2)/((E1*I1)+(E2*I2))                   # Maximum tensile stress in ksi where y = -h2\n",
-      "s2c = -(M*(-(h2-0.5))*E2)/((E1*I1)+(E2*I2))             # Minimum tensile stress in ksi where y = -(h2-0.5)\n",
-      "print \"Maximum tensile stress in steel is\", round(s2a,3)*1000, \"psi\"\n",
-      "print \"Minimum tensile stress in steel is\", round(s2c,3)*1000, \"psi\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum compressive stress in wood is -1305.0 psi\n",
-        "Maximum tensile stress in wood is 251.0 psi\n",
-        "Maximum tensile stress in steel is 7622.0 psi\n",
-        "Minimum tensile stress in steel is 5028.0 psi\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 6.2, page no. 402"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "maximum tensile and compressive stresses in the faces and the core using: general theory for composite beams and \n",
-      "approximate theory for sandwich beams\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "\n",
-      "M = 3000                        # moment in N-m\n",
-      "t = 0.005                       # thickness of alluminiun in m\n",
-      "E1 = 72e09                      # Modulus of elasticity of alluminium in Pa\n",
-      "E2 = 800e06                     # Modulus of elasticity of Plastic core in Pa\n",
-      "b = 0.2                         # Width of cross section in m\n",
-      "h = 0.160                       # Height of cross section in m\n",
-      "hc = 0.150                      # Height of Plastic core cross section in m\n",
-      "\n",
-      "#calculation\n",
-      "I1 = (b/12.0)*(h**3 - hc**3)    # Moment of inertia of alluminium cross section\n",
-      "I2 = (b/12.0)*(hc**3)           # Moment of inertia of Plastic core cross section\n",
-      "f = (E1*I1) + (E2*I2)           # Flexural rigidity of the cross section\n",
-      "s1_max = (M*(h/2.0)*E1)/f \n",
-      "s1c = -s1_max                   # Maximum compressive stress in alluminium core in Pa\n",
-      "s1t = s1_max                    # Maximum tensile stress in alluminium core in Pa\n",
-      "print \"Maximum compressive stress on alluminium face by the general theory for composite beams is\", s1c, \"Pa\"\n",
-      "print \"Maximum tensile stress on alluminium face by the general theory for composite beams is\", s1t, \"Pa\"\n",
-      "s2_max = (M*(hc/2.0)*E2)/f \n",
-      "s2c = -s2_max                   # Maximum compressive stress in Plastic core in Pa\n",
-      "s2t = s2_max                    # Maximum tensile stress in Plastic core in Pa\n",
-      "print \"Maximum compressive stress in plastic core by the general theory for composite beams is\", s2c, \"Pa\"\n",
-      "print \"Maximum tensile stress in plastic core by the general theory for composite beams is\", s2t, \"Pa\"\n",
-      "\n",
-      "# Part (b) : Calculation from approximate theory of sandwitch\n",
-      "s1_max1 = (M*h)/(2*I1) \n",
-      "s1c1 = -s1_max1                 # Maximum compressive stress in alluminium core in Pa\n",
-      "s1t1 = s1_max1                  # Maximum tensile stress in alluminium core in Pa\n",
-      "print \"Maximum compressive stress on alluminium core by approximate theory of sandwitch is\", s1c1, \"Pa\"\n",
-      "print \"Maximum tensile stress on alluminium core by approximate theory of sandwitch is\", s1t1, \"Pa\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum compressive stress on alluminium face by the general theory for composite beams is -18984838.497 Pa\n",
-        "Maximum tensile stress on alluminium face by the general theory for composite beams is 18984838.497 Pa\n",
-        "Maximum compressive stress in plastic core by the general theory for composite beams is -197758.734344 Pa\n",
-        "Maximum tensile stress in plastic core by the general theory for composite beams is 197758.734344 Pa\n",
-        "Maximum compressive stress on alluminium core by approximate theory of sandwitch is -19972260.749 Pa\n",
-        "Maximum tensile stress on alluminium core by approximate theory of sandwitch is 19972260.749 Pa\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 6.3, page no. 407"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculate largest tensile & compressive stresses in the wood\n",
-      "also, the maximum and minimum tensile stresses in the steel\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "# 4*6 inch wood beam dimension\n",
-      "# 4*0.5 inch steel beam dimension\n",
-      "M = 60.0                      # Moment in k-in\n",
-      "E1 = 1500.0                   # in Ksi\n",
-      "E2 = 30000.0                  # in Ksi\n",
-      "b = 4.0                       # width of crosssection in inch\n",
-      "\n",
-      "#calculation\n",
-      "# Transformed Section\n",
-      "n = E2/E1                   # Modular ratio\n",
-      "b1 = n*4                    # Increased width of transformed cross section\n",
-      "\n",
-      "# Neutral axis\n",
-      "h1 = ((3*4*6)+(80*0.5*6.25))/((4*6)+(80*0.5)) # Dismath.tance between top surface and neutral axis of the beam in inch\n",
-      "h2 = 6.5 - h1  # in inch\n",
-      "\n",
-      "# Moment of inertia\n",
-      "It = (1.0/12.0)*(4*6**3) + (4*6)*(h1-3)**2 + (1.0/12.0)*(80*0.5**3) + (80*0.5)*(h2-0.25)**2  # Moment of inertia of transformed cross section\n",
-      "\n",
-      "# Material 1\n",
-      "s1a = -(M*h1)/It  # Maximum tensile stress in ksi where y = h1\n",
-      "s1c = -(M*(-(h2-0.5)))/It  # Maximum compressive stress in ksi where y = -(h2-0.5)\n",
-      "print \"Maximum tensile stress in wood is\", s1a*1000, \"psi\"\n",
-      "print \"Maximum compressive stress in wood is\", s1c*1000, \"psi\"\n",
-      "\n",
-      "# Material 2\n",
-      "s2a = -(M*(-h2)*n)/It  # Maximum tensile stress in ksi where y = -h2\n",
-      "s2c = -(M*(-(h2-0.5)*n))/It  # Minimum tensile stress in ksi where y = -(h2-0.5)\n",
-      "print \"Maximum tensile stress in steel\", s2a*1000, \"psi\"\n",
-      "print \"Minimum tensile stress in steel\", s2c*1000, \"psi\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum tensile stress in wood is -1305.28781191 psi\n",
-        "Maximum compressive stress in wood is 251.328709125 psi\n",
-        "Maximum tensile stress in steel 7620.9350509 psi\n",
-        "Minimum tensile stress in steel 5026.57418251 psi\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 6.4,page no. 412"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "maximum tensile and compressive stresses in the beam\n",
-      "\"\"\"\n",
-      "\n",
-      "import math\n",
-      "import numpy\n",
-      "\n",
-      "#initialisation\n",
-      "\n",
-      "q = 3000.0                    # Uniform load intensity in N/m\n",
-      "a = 26.57                   # tilt of the beam in degree\n",
-      "b = 0.1                     # width of the beam\n",
-      "h = 0.15                    # height of the beam\n",
-      "L = 1.6                     # Span of the beam\n",
-      "\n",
-      "#calculation\n",
-      "qy = q*math.cos(math.radians(a))  # Component of q in y direction\n",
-      "qz = q*math.sin(math.radians(a))  # Component of q in z direction\n",
-      "My = (qz*L**2.0)/8.0                      # Maximum bending moment in y direction\n",
-      "Mz = (qy*L**2.0)/8.0                      # Maximum bending moment in z direction\n",
-      "Iy = (h*b**3.0)/12.0                      # Moment of inertia along y\n",
-      "Iz = (b*h**3.0)/12.0                      # Moment of inertia alon z\n",
-      "s = ((3*q*L**2)/(4*b*h))*((math.sin(math.radians(a))/b)+(math.cos(math.radians(a))/h))\n",
-      "sc = -s  # Maximum compressive stress\n",
-      "st = s # Maximum tensile stress\n",
-      "print \"Maximum compressive stress in the beam is\", sc, \"Pa\"\n",
-      "print \"Maximum tensile stress in the beam is\", st, \"Pa\"\n",
-      "\n",
-      "# Neutral axis\n",
-      "l = (h/b)**2\n",
-      "t = math.sin(math.radians(a)/math.cos(math.radians(a)))\n",
-      "j = l*(math.sin(math.radians(a)/math.cos(math.radians(a))))\n",
-      "be = math.degrees((numpy.arctan((j))))  # Inclination of Neutral axis to z axis\n",
-      "print \"Inclination of Neutral axis to z axis is\", round(be,2), \"degree\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum compressive stress in the beam is -4007231.57248 Pa\n",
-        "Maximum tensile stress in the beam is 4007231.57248 Pa\n",
-        "Inclination of Neutral axis to z axis is 48.11 degree\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 6.5, page no. 414"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "maximum bending stresses in the beam for various conditions\n",
-      "\"\"\"\n",
-      "\n",
-      "import math\n",
-      "import numpy \n",
-      "\n",
-      "#initialisation\n",
-      "L = 12.0                          # Length of the beam in ft\n",
-      "P = 10.0                          # Load in k acting in vertical direction\n",
-      "\n",
-      "#Part (a)\n",
-      "h = 24.0                          # Height of beam in inch\n",
-      "Iz = 2100                         # Moment of inertia along z axis in in4\n",
-      "Iy = 42.2                         # Moment of inertia along y axis in in4\n",
-      "\n",
-      "#calculation\n",
-      "s_max = (P*(h/2.0)*L*12)/Iz       # Maximum stress in Ksi\n",
-      "print \"Maximum tensile stress in the beam at the top of the beam\", round(s_max*1000), \"psi\"\n",
-      "print \"Maximum compressive stress in the beam at the bottom of the beam\", round(-s_max*1000), \"psi\"\n",
-      "\n",
-      "#Part (b)\n",
-      "a = 1                                     # Angle between y axis and the load\n",
-      "My = -(P*math.sin(math.radians(a)))*L*12  # Moment along y-axis in K-in\n",
-      "Mz = -(P*math.cos(math.radians(a)))*L*12  # Moment along z-axis in K-in\n",
-      "ba = math.radians(numpy.arctan(((My*Iz)/(Mz*Iy)))) # Orientation of neutral axis\n",
-      "z = -3.5\n",
-      "y = 12.0                                  # Coordinates of the point A and B where maximum stress occur\n",
-      "s = ((My*z)/Iy)-((Mz*y)/Iz)               # Stress in Ksi\n",
-      "sa = s                                    # Tensile stress at A\n",
-      "sb = -s                                   # Compressive stress in B\n",
-      "print \"The tensile stress at A is\", round(sa*1000), \"psi\"\n",
-      "print \"The compressive stress at B is\", round(sb*1000), \"psi\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum tensile stress in the beam at the top of the beam 8229.0 psi\n",
-        "Maximum compressive stress in the beam at the bottom of the beam -8229.0 psi\n",
-        "The tensile stress at A is 10312.0 psi\n",
-        "The compressive stress at B is -10312.0 psi\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 6.6, page no. 420"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "the bending stresses at points A and B\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "import numpy\n",
-      "\n",
-      "#initialisation\n",
-      "M = 15                              # Bending moment in k-in\n",
-      "t = 10                              # Angle between line of action of moment and z-axis\n",
-      "\n",
-      "# Properties of cross section\n",
-      "c = 0.634                            # Location of centroid on the axis of symmetry\n",
-      "Iy = 2.28                            # Moment of inertia in y-direction in in4\n",
-      "Iz = 67.4                            # Moment of inertia in z-direction in in4\n",
-      "ya = 5\n",
-      "za = -2.6+0.634              # Coordinates of point A\n",
-      "yb = -5\n",
-      "zb = 0.634                  # Coordinates of point B\n",
-      "My = M*math.sin(math.radians(t))     # Moment along y-axis\n",
-      "Mz = M*math.cos(math.radians(t))     # Moment along z-axis\n",
-      "sa = ((My*za)/Iy)-((Mz*ya)/Iz)       # Bending stress at point A in ksi\n",
-      "sb = ((My*zb)/Iy)-((Mz*yb)/Iz)       # Bending stress at point B in ksi\n",
-      "print \"The bending stress at point A is\", round(sa*1000), \"psi\"\n",
-      "print \"The bending stress at point B is\", round(sb*1000), \"psi\"\n",
-      "\n",
-      "# Neutral axis\n",
-      "j = (Iz/Iy)*(math.sin(math.radians(t)/math.cos(math.radians(t))))\n",
-      "be = numpy.degrees(numpy.arctan((j)))        # Inclination of neutral axis to z-axis in degree\n",
-      "print \"Inclination of neutral axis to z-axis is\", round(be,1), \"degree\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The bending stress at point A is -3342.0 psi\n",
-        "The bending stress at point B is 1820.0 psi\n",
-        "Inclination of neutral axis to z-axis is 79.1 degree\n"
-       ]
-      }
-     ],
-     "prompt_number": 16
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 6.9, page no. 448"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculate magnitude of the moment M\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialization\n",
-      "b = 5                   # in inch\n",
-      "b1 = 4                  # in inch\n",
-      "h = 9                   # in inch\n",
-      "h1 = 7.5                # in inch\n",
-      "sy = 33                 # stress along y axis in ksi\n",
-      "\n",
-      "#Calculations\n",
-      "M = (sy/12.0)*((3*b*h**2)-(b+(2*b1))*(h1**2))  # Bending moment acting in k-in\n",
-      "\n",
-      "#Result\n",
-      "print \"the magnitude of the moment M is\", round(M), \"k-in\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the magnitude of the moment M is 1330.0 k-in\n"
-       ]
-      }
-     ],
-     "prompt_number": 7
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Testing_the_interface/chapter6_2.ipynb b/Testing_the_interface/chapter6_2.ipynb
deleted file mode 100755
index 344830c9..00000000
--- a/Testing_the_interface/chapter6_2.ipynb
+++ /dev/null
@@ -1,444 +0,0 @@
-{
- "metadata": {
-  "name": ""
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 6: Stresses in Beams Advanced Topics"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 6.1, page no. 400"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "largest tensile and compressive stresses in the wood & the max. and min. tensile stresses in the steel\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "# 4*6 inch wood beam dimension\n",
-      "# 4*0.5 inch steel beam dimension\n",
-      "M = 60.0                          # Moment in k-in\n",
-      "E1 = 1500.                       # in Ksi\n",
-      "E2 = 30000.0                      # in Ksi\n",
-      "h1 = 5.031                      # Distance between top surface and neutral axis of the beam in inch by solving 1500*(h1-3)*24 + 30000*(h1-6.25)*2 = 0\n",
-      "\n",
-      "#calculation\n",
-      "h2 = 6.5 - h1 \n",
-      "I1 = (1.0/12.0)*(4*6**3) + (4*6)*(h1-3)**2              # Momeny of inertia of the wooden cross section\n",
-      "I2 = (1.0/12.0)*(4*0.5**3) + (4*0.5)*(h2-0.25)**2       # Momeny of inertia of the steel cross section\n",
-      "I = I1 + I2                                             # Moment of inertia of whole cross section\n",
-      "\n",
-      "# Material 1\n",
-      "s1a = -(M*h1*E1)/((E1*I1)+(E2*I2))                      # Maximum compressive stress in ksi where y = h1\n",
-      "s1c = -(M*(-(h2-0.5))*E1)/((E1*I1)+(E2*I2))             # Maximum tensile stress in ksi where y = -(h2-0.5)\n",
-      "print \"Maximum compressive stress in wood is\", round(s1a,3)*1000, \"psi\"\n",
-      "print \"Maximum tensile stress in wood is\", round(s1c,3)*1000, \"psi\"\n",
-      "\n",
-      "# Material 2\n",
-      "s2a = -(M*(-h2)*E2)/((E1*I1)+(E2*I2))                   # Maximum tensile stress in ksi where y = -h2\n",
-      "s2c = -(M*(-(h2-0.5))*E2)/((E1*I1)+(E2*I2))             # Minimum tensile stress in ksi where y = -(h2-0.5)\n",
-      "print \"Maximum tensile stress in steel is\", round(s2a,3)*1000, \"psi\"\n",
-      "print \"Minimum tensile stress in steel is\", round(s2c,3)*1000, \"psi\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum compressive stress in wood is -1305.0 psi\n",
-        "Maximum tensile stress in wood is 251.0 psi\n",
-        "Maximum tensile stress in steel is 7622.0 psi\n",
-        "Minimum tensile stress in steel is 5028.0 psi\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 6.2, page no. 402"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "maximum tensile and compressive stresses in the faces and the core using: general theory for composite beams and \n",
-      "approximate theory for sandwich beams\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "\n",
-      "M = 3000                        # moment in N-m\n",
-      "t = 0.005                       # thickness of alluminiun in m\n",
-      "E1 = 72e09                      # Modulus of elasticity of alluminium in Pa\n",
-      "E2 = 800e06                     # Modulus of elasticity of Plastic core in Pa\n",
-      "b = 0.2                         # Width of cross section in m\n",
-      "h = 0.160                       # Height of cross section in m\n",
-      "hc = 0.150                      # Height of Plastic core cross section in m\n",
-      "\n",
-      "#calculation\n",
-      "I1 = (b/12.0)*(h**3 - hc**3)    # Moment of inertia of alluminium cross section\n",
-      "I2 = (b/12.0)*(hc**3)           # Moment of inertia of Plastic core cross section\n",
-      "f = (E1*I1) + (E2*I2)           # Flexural rigidity of the cross section\n",
-      "s1_max = (M*(h/2.0)*E1)/f \n",
-      "s1c = -s1_max                   # Maximum compressive stress in alluminium core in Pa\n",
-      "s1t = s1_max                    # Maximum tensile stress in alluminium core in Pa\n",
-      "print \"Maximum compressive stress on alluminium face by the general theory for composite beams is\", s1c, \"Pa\"\n",
-      "print \"Maximum tensile stress on alluminium face by the general theory for composite beams is\", s1t, \"Pa\"\n",
-      "s2_max = (M*(hc/2.0)*E2)/f \n",
-      "s2c = -s2_max                   # Maximum compressive stress in Plastic core in Pa\n",
-      "s2t = s2_max                    # Maximum tensile stress in Plastic core in Pa\n",
-      "print \"Maximum compressive stress in plastic core by the general theory for composite beams is\", s2c, \"Pa\"\n",
-      "print \"Maximum tensile stress in plastic core by the general theory for composite beams is\", s2t, \"Pa\"\n",
-      "\n",
-      "# Part (b) : Calculation from approximate theory of sandwitch\n",
-      "s1_max1 = (M*h)/(2*I1) \n",
-      "s1c1 = -s1_max1                 # Maximum compressive stress in alluminium core in Pa\n",
-      "s1t1 = s1_max1                  # Maximum tensile stress in alluminium core in Pa\n",
-      "print \"Maximum compressive stress on alluminium core by approximate theory of sandwitch is\", s1c1, \"Pa\"\n",
-      "print \"Maximum tensile stress on alluminium core by approximate theory of sandwitch is\", s1t1, \"Pa\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum compressive stress on alluminium face by the general theory for composite beams is -18984838.497 Pa\n",
-        "Maximum tensile stress on alluminium face by the general theory for composite beams is 18984838.497 Pa\n",
-        "Maximum compressive stress in plastic core by the general theory for composite beams is -197758.734344 Pa\n",
-        "Maximum tensile stress in plastic core by the general theory for composite beams is 197758.734344 Pa\n",
-        "Maximum compressive stress on alluminium core by approximate theory of sandwitch is -19972260.749 Pa\n",
-        "Maximum tensile stress on alluminium core by approximate theory of sandwitch is 19972260.749 Pa\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 6.3, page no. 407"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculate largest tensile & compressive stresses in the wood\n",
-      "also, the maximum and minimum tensile stresses in the steel\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "# 4*6 inch wood beam dimension\n",
-      "# 4*0.5 inch steel beam dimension\n",
-      "M = 60.0                      # Moment in k-in\n",
-      "E1 = 1500.0                   # in Ksi\n",
-      "E2 = 30000.0                  # in Ksi\n",
-      "b = 4.0                       # width of crosssection in inch\n",
-      "\n",
-      "#calculation\n",
-      "# Transformed Section\n",
-      "n = E2/E1                   # Modular ratio\n",
-      "b1 = n*4                    # Increased width of transformed cross section\n",
-      "\n",
-      "# Neutral axis\n",
-      "h1 = ((3*4*6)+(80*0.5*6.25))/((4*6)+(80*0.5)) # Dismath.tance between top surface and neutral axis of the beam in inch\n",
-      "h2 = 6.5 - h1  # in inch\n",
-      "\n",
-      "# Moment of inertia\n",
-      "It = (1.0/12.0)*(4*6**3) + (4*6)*(h1-3)**2 + (1.0/12.0)*(80*0.5**3) + (80*0.5)*(h2-0.25)**2  # Moment of inertia of transformed cross section\n",
-      "\n",
-      "# Material 1\n",
-      "s1a = -(M*h1)/It  # Maximum tensile stress in ksi where y = h1\n",
-      "s1c = -(M*(-(h2-0.5)))/It  # Maximum compressive stress in ksi where y = -(h2-0.5)\n",
-      "print \"Maximum tensile stress in wood is\", s1a*1000, \"psi\"\n",
-      "print \"Maximum compressive stress in wood is\", s1c*1000, \"psi\"\n",
-      "\n",
-      "# Material 2\n",
-      "s2a = -(M*(-h2)*n)/It  # Maximum tensile stress in ksi where y = -h2\n",
-      "s2c = -(M*(-(h2-0.5)*n))/It  # Minimum tensile stress in ksi where y = -(h2-0.5)\n",
-      "print \"Maximum tensile stress in steel\", s2a*1000, \"psi\"\n",
-      "print \"Minimum tensile stress in steel\", s2c*1000, \"psi\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum tensile stress in wood is -1305.28781191 psi\n",
-        "Maximum compressive stress in wood is 251.328709125 psi\n",
-        "Maximum tensile stress in steel 7620.9350509 psi\n",
-        "Minimum tensile stress in steel 5026.57418251 psi\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 6.4,page no. 412"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "maximum tensile and compressive stresses in the beam\n",
-      "\"\"\"\n",
-      "\n",
-      "import math\n",
-      "import numpy\n",
-      "\n",
-      "#initialisation\n",
-      "\n",
-      "q = 3000.0                    # Uniform load intensity in N/m\n",
-      "a = 26.57                   # tilt of the beam in degree\n",
-      "b = 0.1                     # width of the beam\n",
-      "h = 0.15                    # height of the beam\n",
-      "L = 1.6                     # Span of the beam\n",
-      "\n",
-      "#calculation\n",
-      "qy = q*math.cos(math.radians(a))  # Component of q in y direction\n",
-      "qz = q*math.sin(math.radians(a))  # Component of q in z direction\n",
-      "My = (qz*L**2.0)/8.0                      # Maximum bending moment in y direction\n",
-      "Mz = (qy*L**2.0)/8.0                      # Maximum bending moment in z direction\n",
-      "Iy = (h*b**3.0)/12.0                      # Moment of inertia along y\n",
-      "Iz = (b*h**3.0)/12.0                      # Moment of inertia alon z\n",
-      "s = ((3*q*L**2)/(4*b*h))*((math.sin(math.radians(a))/b)+(math.cos(math.radians(a))/h))\n",
-      "sc = -s  # Maximum compressive stress\n",
-      "st = s # Maximum tensile stress\n",
-      "print \"Maximum compressive stress in the beam is\", sc, \"Pa\"\n",
-      "print \"Maximum tensile stress in the beam is\", st, \"Pa\"\n",
-      "\n",
-      "# Neutral axis\n",
-      "l = (h/b)**2\n",
-      "t = math.sin(math.radians(a)/math.cos(math.radians(a)))\n",
-      "j = l*(math.sin(math.radians(a)/math.cos(math.radians(a))))\n",
-      "be = math.degrees((numpy.arctan((j))))  # Inclination of Neutral axis to z axis\n",
-      "print \"Inclination of Neutral axis to z axis is\", round(be,2), \"degree\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum compressive stress in the beam is -4007231.57248 Pa\n",
-        "Maximum tensile stress in the beam is 4007231.57248 Pa\n",
-        "Inclination of Neutral axis to z axis is 48.11 degree\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 6.5, page no. 414"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "maximum bending stresses in the beam for various conditions\n",
-      "\"\"\"\n",
-      "\n",
-      "import math\n",
-      "import numpy \n",
-      "\n",
-      "#initialisation\n",
-      "L = 12.0                          # Length of the beam in ft\n",
-      "P = 10.0                          # Load in k acting in vertical direction\n",
-      "\n",
-      "#Part (a)\n",
-      "h = 24.0                          # Height of beam in inch\n",
-      "Iz = 2100                         # Moment of inertia along z axis in in4\n",
-      "Iy = 42.2                         # Moment of inertia along y axis in in4\n",
-      "\n",
-      "#calculation\n",
-      "s_max = (P*(h/2.0)*L*12)/Iz       # Maximum stress in Ksi\n",
-      "print \"Maximum tensile stress in the beam at the top of the beam\", round(s_max*1000), \"psi\"\n",
-      "print \"Maximum compressive stress in the beam at the bottom of the beam\", round(-s_max*1000), \"psi\"\n",
-      "\n",
-      "#Part (b)\n",
-      "a = 1                                     # Angle between y axis and the load\n",
-      "My = -(P*math.sin(math.radians(a)))*L*12  # Moment along y-axis in K-in\n",
-      "Mz = -(P*math.cos(math.radians(a)))*L*12  # Moment along z-axis in K-in\n",
-      "ba = math.radians(numpy.arctan(((My*Iz)/(Mz*Iy)))) # Orientation of neutral axis\n",
-      "z = -3.5\n",
-      "y = 12.0                                  # Coordinates of the point A and B where maximum stress occur\n",
-      "s = ((My*z)/Iy)-((Mz*y)/Iz)               # Stress in Ksi\n",
-      "sa = s                                    # Tensile stress at A\n",
-      "sb = -s                                   # Compressive stress in B\n",
-      "print \"The tensile stress at A is\", round(sa*1000), \"psi\"\n",
-      "print \"The compressive stress at B is\", round(sb*1000), \"psi\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum tensile stress in the beam at the top of the beam 8229.0 psi\n",
-        "Maximum compressive stress in the beam at the bottom of the beam -8229.0 psi\n",
-        "The tensile stress at A is 10312.0 psi\n",
-        "The compressive stress at B is -10312.0 psi\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 6.6, page no. 420"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "the bending stresses at points A and B\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "import numpy\n",
-      "\n",
-      "#initialisation\n",
-      "M = 15                              # Bending moment in k-in\n",
-      "t = 10                              # Angle between line of action of moment and z-axis\n",
-      "\n",
-      "# Properties of cross section\n",
-      "c = 0.634                            # Location of centroid on the axis of symmetry\n",
-      "Iy = 2.28                            # Moment of inertia in y-direction in in4\n",
-      "Iz = 67.4                            # Moment of inertia in z-direction in in4\n",
-      "ya = 5\n",
-      "za = -2.6+0.634              # Coordinates of point A\n",
-      "yb = -5\n",
-      "zb = 0.634                  # Coordinates of point B\n",
-      "My = M*math.sin(math.radians(t))     # Moment along y-axis\n",
-      "Mz = M*math.cos(math.radians(t))     # Moment along z-axis\n",
-      "sa = ((My*za)/Iy)-((Mz*ya)/Iz)       # Bending stress at point A in ksi\n",
-      "sb = ((My*zb)/Iy)-((Mz*yb)/Iz)       # Bending stress at point B in ksi\n",
-      "print \"The bending stress at point A is\", round(sa*1000), \"psi\"\n",
-      "print \"The bending stress at point B is\", round(sb*1000), \"psi\"\n",
-      "\n",
-      "# Neutral axis\n",
-      "j = (Iz/Iy)*(math.sin(math.radians(t)/math.cos(math.radians(t))))\n",
-      "be = numpy.degrees(numpy.arctan((j)))        # Inclination of neutral axis to z-axis in degree\n",
-      "print \"Inclination of neutral axis to z-axis is\", round(be,1), \"degree\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The bending stress at point A is -3342.0 psi\n",
-        "The bending stress at point B is 1820.0 psi\n",
-        "Inclination of neutral axis to z-axis is 79.1 degree\n"
-       ]
-      }
-     ],
-     "prompt_number": 16
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 6.9, page no. 448"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculate magnitude of the moment M\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialization\n",
-      "b = 5                   # in inch\n",
-      "b1 = 4                  # in inch\n",
-      "h = 9                   # in inch\n",
-      "h1 = 7.5                # in inch\n",
-      "sy = 33                 # stress along y axis in ksi\n",
-      "\n",
-      "#Calculations\n",
-      "M = (sy/12.0)*((3*b*h**2)-(b+(2*b1))*(h1**2))  # Bending moment acting in k-in\n",
-      "\n",
-      "#Result\n",
-      "print \"the magnitude of the moment M is\", round(M), \"k-in\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the magnitude of the moment M is 1330.0 k-in\n"
-       ]
-      }
-     ],
-     "prompt_number": 7
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Testing_the_interface/chapter6_3.ipynb b/Testing_the_interface/chapter6_3.ipynb
deleted file mode 100755
index 344830c9..00000000
--- a/Testing_the_interface/chapter6_3.ipynb
+++ /dev/null
@@ -1,444 +0,0 @@
-{
- "metadata": {
-  "name": ""
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 6: Stresses in Beams Advanced Topics"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 6.1, page no. 400"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "largest tensile and compressive stresses in the wood & the max. and min. tensile stresses in the steel\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "# 4*6 inch wood beam dimension\n",
-      "# 4*0.5 inch steel beam dimension\n",
-      "M = 60.0                          # Moment in k-in\n",
-      "E1 = 1500.                       # in Ksi\n",
-      "E2 = 30000.0                      # in Ksi\n",
-      "h1 = 5.031                      # Distance between top surface and neutral axis of the beam in inch by solving 1500*(h1-3)*24 + 30000*(h1-6.25)*2 = 0\n",
-      "\n",
-      "#calculation\n",
-      "h2 = 6.5 - h1 \n",
-      "I1 = (1.0/12.0)*(4*6**3) + (4*6)*(h1-3)**2              # Momeny of inertia of the wooden cross section\n",
-      "I2 = (1.0/12.0)*(4*0.5**3) + (4*0.5)*(h2-0.25)**2       # Momeny of inertia of the steel cross section\n",
-      "I = I1 + I2                                             # Moment of inertia of whole cross section\n",
-      "\n",
-      "# Material 1\n",
-      "s1a = -(M*h1*E1)/((E1*I1)+(E2*I2))                      # Maximum compressive stress in ksi where y = h1\n",
-      "s1c = -(M*(-(h2-0.5))*E1)/((E1*I1)+(E2*I2))             # Maximum tensile stress in ksi where y = -(h2-0.5)\n",
-      "print \"Maximum compressive stress in wood is\", round(s1a,3)*1000, \"psi\"\n",
-      "print \"Maximum tensile stress in wood is\", round(s1c,3)*1000, \"psi\"\n",
-      "\n",
-      "# Material 2\n",
-      "s2a = -(M*(-h2)*E2)/((E1*I1)+(E2*I2))                   # Maximum tensile stress in ksi where y = -h2\n",
-      "s2c = -(M*(-(h2-0.5))*E2)/((E1*I1)+(E2*I2))             # Minimum tensile stress in ksi where y = -(h2-0.5)\n",
-      "print \"Maximum tensile stress in steel is\", round(s2a,3)*1000, \"psi\"\n",
-      "print \"Minimum tensile stress in steel is\", round(s2c,3)*1000, \"psi\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum compressive stress in wood is -1305.0 psi\n",
-        "Maximum tensile stress in wood is 251.0 psi\n",
-        "Maximum tensile stress in steel is 7622.0 psi\n",
-        "Minimum tensile stress in steel is 5028.0 psi\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 6.2, page no. 402"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "maximum tensile and compressive stresses in the faces and the core using: general theory for composite beams and \n",
-      "approximate theory for sandwich beams\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "\n",
-      "M = 3000                        # moment in N-m\n",
-      "t = 0.005                       # thickness of alluminiun in m\n",
-      "E1 = 72e09                      # Modulus of elasticity of alluminium in Pa\n",
-      "E2 = 800e06                     # Modulus of elasticity of Plastic core in Pa\n",
-      "b = 0.2                         # Width of cross section in m\n",
-      "h = 0.160                       # Height of cross section in m\n",
-      "hc = 0.150                      # Height of Plastic core cross section in m\n",
-      "\n",
-      "#calculation\n",
-      "I1 = (b/12.0)*(h**3 - hc**3)    # Moment of inertia of alluminium cross section\n",
-      "I2 = (b/12.0)*(hc**3)           # Moment of inertia of Plastic core cross section\n",
-      "f = (E1*I1) + (E2*I2)           # Flexural rigidity of the cross section\n",
-      "s1_max = (M*(h/2.0)*E1)/f \n",
-      "s1c = -s1_max                   # Maximum compressive stress in alluminium core in Pa\n",
-      "s1t = s1_max                    # Maximum tensile stress in alluminium core in Pa\n",
-      "print \"Maximum compressive stress on alluminium face by the general theory for composite beams is\", s1c, \"Pa\"\n",
-      "print \"Maximum tensile stress on alluminium face by the general theory for composite beams is\", s1t, \"Pa\"\n",
-      "s2_max = (M*(hc/2.0)*E2)/f \n",
-      "s2c = -s2_max                   # Maximum compressive stress in Plastic core in Pa\n",
-      "s2t = s2_max                    # Maximum tensile stress in Plastic core in Pa\n",
-      "print \"Maximum compressive stress in plastic core by the general theory for composite beams is\", s2c, \"Pa\"\n",
-      "print \"Maximum tensile stress in plastic core by the general theory for composite beams is\", s2t, \"Pa\"\n",
-      "\n",
-      "# Part (b) : Calculation from approximate theory of sandwitch\n",
-      "s1_max1 = (M*h)/(2*I1) \n",
-      "s1c1 = -s1_max1                 # Maximum compressive stress in alluminium core in Pa\n",
-      "s1t1 = s1_max1                  # Maximum tensile stress in alluminium core in Pa\n",
-      "print \"Maximum compressive stress on alluminium core by approximate theory of sandwitch is\", s1c1, \"Pa\"\n",
-      "print \"Maximum tensile stress on alluminium core by approximate theory of sandwitch is\", s1t1, \"Pa\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum compressive stress on alluminium face by the general theory for composite beams is -18984838.497 Pa\n",
-        "Maximum tensile stress on alluminium face by the general theory for composite beams is 18984838.497 Pa\n",
-        "Maximum compressive stress in plastic core by the general theory for composite beams is -197758.734344 Pa\n",
-        "Maximum tensile stress in plastic core by the general theory for composite beams is 197758.734344 Pa\n",
-        "Maximum compressive stress on alluminium core by approximate theory of sandwitch is -19972260.749 Pa\n",
-        "Maximum tensile stress on alluminium core by approximate theory of sandwitch is 19972260.749 Pa\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 6.3, page no. 407"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculate largest tensile & compressive stresses in the wood\n",
-      "also, the maximum and minimum tensile stresses in the steel\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "# 4*6 inch wood beam dimension\n",
-      "# 4*0.5 inch steel beam dimension\n",
-      "M = 60.0                      # Moment in k-in\n",
-      "E1 = 1500.0                   # in Ksi\n",
-      "E2 = 30000.0                  # in Ksi\n",
-      "b = 4.0                       # width of crosssection in inch\n",
-      "\n",
-      "#calculation\n",
-      "# Transformed Section\n",
-      "n = E2/E1                   # Modular ratio\n",
-      "b1 = n*4                    # Increased width of transformed cross section\n",
-      "\n",
-      "# Neutral axis\n",
-      "h1 = ((3*4*6)+(80*0.5*6.25))/((4*6)+(80*0.5)) # Dismath.tance between top surface and neutral axis of the beam in inch\n",
-      "h2 = 6.5 - h1  # in inch\n",
-      "\n",
-      "# Moment of inertia\n",
-      "It = (1.0/12.0)*(4*6**3) + (4*6)*(h1-3)**2 + (1.0/12.0)*(80*0.5**3) + (80*0.5)*(h2-0.25)**2  # Moment of inertia of transformed cross section\n",
-      "\n",
-      "# Material 1\n",
-      "s1a = -(M*h1)/It  # Maximum tensile stress in ksi where y = h1\n",
-      "s1c = -(M*(-(h2-0.5)))/It  # Maximum compressive stress in ksi where y = -(h2-0.5)\n",
-      "print \"Maximum tensile stress in wood is\", s1a*1000, \"psi\"\n",
-      "print \"Maximum compressive stress in wood is\", s1c*1000, \"psi\"\n",
-      "\n",
-      "# Material 2\n",
-      "s2a = -(M*(-h2)*n)/It  # Maximum tensile stress in ksi where y = -h2\n",
-      "s2c = -(M*(-(h2-0.5)*n))/It  # Minimum tensile stress in ksi where y = -(h2-0.5)\n",
-      "print \"Maximum tensile stress in steel\", s2a*1000, \"psi\"\n",
-      "print \"Minimum tensile stress in steel\", s2c*1000, \"psi\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum tensile stress in wood is -1305.28781191 psi\n",
-        "Maximum compressive stress in wood is 251.328709125 psi\n",
-        "Maximum tensile stress in steel 7620.9350509 psi\n",
-        "Minimum tensile stress in steel 5026.57418251 psi\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 6.4,page no. 412"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "maximum tensile and compressive stresses in the beam\n",
-      "\"\"\"\n",
-      "\n",
-      "import math\n",
-      "import numpy\n",
-      "\n",
-      "#initialisation\n",
-      "\n",
-      "q = 3000.0                    # Uniform load intensity in N/m\n",
-      "a = 26.57                   # tilt of the beam in degree\n",
-      "b = 0.1                     # width of the beam\n",
-      "h = 0.15                    # height of the beam\n",
-      "L = 1.6                     # Span of the beam\n",
-      "\n",
-      "#calculation\n",
-      "qy = q*math.cos(math.radians(a))  # Component of q in y direction\n",
-      "qz = q*math.sin(math.radians(a))  # Component of q in z direction\n",
-      "My = (qz*L**2.0)/8.0                      # Maximum bending moment in y direction\n",
-      "Mz = (qy*L**2.0)/8.0                      # Maximum bending moment in z direction\n",
-      "Iy = (h*b**3.0)/12.0                      # Moment of inertia along y\n",
-      "Iz = (b*h**3.0)/12.0                      # Moment of inertia alon z\n",
-      "s = ((3*q*L**2)/(4*b*h))*((math.sin(math.radians(a))/b)+(math.cos(math.radians(a))/h))\n",
-      "sc = -s  # Maximum compressive stress\n",
-      "st = s # Maximum tensile stress\n",
-      "print \"Maximum compressive stress in the beam is\", sc, \"Pa\"\n",
-      "print \"Maximum tensile stress in the beam is\", st, \"Pa\"\n",
-      "\n",
-      "# Neutral axis\n",
-      "l = (h/b)**2\n",
-      "t = math.sin(math.radians(a)/math.cos(math.radians(a)))\n",
-      "j = l*(math.sin(math.radians(a)/math.cos(math.radians(a))))\n",
-      "be = math.degrees((numpy.arctan((j))))  # Inclination of Neutral axis to z axis\n",
-      "print \"Inclination of Neutral axis to z axis is\", round(be,2), \"degree\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum compressive stress in the beam is -4007231.57248 Pa\n",
-        "Maximum tensile stress in the beam is 4007231.57248 Pa\n",
-        "Inclination of Neutral axis to z axis is 48.11 degree\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 6.5, page no. 414"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "maximum bending stresses in the beam for various conditions\n",
-      "\"\"\"\n",
-      "\n",
-      "import math\n",
-      "import numpy \n",
-      "\n",
-      "#initialisation\n",
-      "L = 12.0                          # Length of the beam in ft\n",
-      "P = 10.0                          # Load in k acting in vertical direction\n",
-      "\n",
-      "#Part (a)\n",
-      "h = 24.0                          # Height of beam in inch\n",
-      "Iz = 2100                         # Moment of inertia along z axis in in4\n",
-      "Iy = 42.2                         # Moment of inertia along y axis in in4\n",
-      "\n",
-      "#calculation\n",
-      "s_max = (P*(h/2.0)*L*12)/Iz       # Maximum stress in Ksi\n",
-      "print \"Maximum tensile stress in the beam at the top of the beam\", round(s_max*1000), \"psi\"\n",
-      "print \"Maximum compressive stress in the beam at the bottom of the beam\", round(-s_max*1000), \"psi\"\n",
-      "\n",
-      "#Part (b)\n",
-      "a = 1                                     # Angle between y axis and the load\n",
-      "My = -(P*math.sin(math.radians(a)))*L*12  # Moment along y-axis in K-in\n",
-      "Mz = -(P*math.cos(math.radians(a)))*L*12  # Moment along z-axis in K-in\n",
-      "ba = math.radians(numpy.arctan(((My*Iz)/(Mz*Iy)))) # Orientation of neutral axis\n",
-      "z = -3.5\n",
-      "y = 12.0                                  # Coordinates of the point A and B where maximum stress occur\n",
-      "s = ((My*z)/Iy)-((Mz*y)/Iz)               # Stress in Ksi\n",
-      "sa = s                                    # Tensile stress at A\n",
-      "sb = -s                                   # Compressive stress in B\n",
-      "print \"The tensile stress at A is\", round(sa*1000), \"psi\"\n",
-      "print \"The compressive stress at B is\", round(sb*1000), \"psi\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum tensile stress in the beam at the top of the beam 8229.0 psi\n",
-        "Maximum compressive stress in the beam at the bottom of the beam -8229.0 psi\n",
-        "The tensile stress at A is 10312.0 psi\n",
-        "The compressive stress at B is -10312.0 psi\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 6.6, page no. 420"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "the bending stresses at points A and B\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "import numpy\n",
-      "\n",
-      "#initialisation\n",
-      "M = 15                              # Bending moment in k-in\n",
-      "t = 10                              # Angle between line of action of moment and z-axis\n",
-      "\n",
-      "# Properties of cross section\n",
-      "c = 0.634                            # Location of centroid on the axis of symmetry\n",
-      "Iy = 2.28                            # Moment of inertia in y-direction in in4\n",
-      "Iz = 67.4                            # Moment of inertia in z-direction in in4\n",
-      "ya = 5\n",
-      "za = -2.6+0.634              # Coordinates of point A\n",
-      "yb = -5\n",
-      "zb = 0.634                  # Coordinates of point B\n",
-      "My = M*math.sin(math.radians(t))     # Moment along y-axis\n",
-      "Mz = M*math.cos(math.radians(t))     # Moment along z-axis\n",
-      "sa = ((My*za)/Iy)-((Mz*ya)/Iz)       # Bending stress at point A in ksi\n",
-      "sb = ((My*zb)/Iy)-((Mz*yb)/Iz)       # Bending stress at point B in ksi\n",
-      "print \"The bending stress at point A is\", round(sa*1000), \"psi\"\n",
-      "print \"The bending stress at point B is\", round(sb*1000), \"psi\"\n",
-      "\n",
-      "# Neutral axis\n",
-      "j = (Iz/Iy)*(math.sin(math.radians(t)/math.cos(math.radians(t))))\n",
-      "be = numpy.degrees(numpy.arctan((j)))        # Inclination of neutral axis to z-axis in degree\n",
-      "print \"Inclination of neutral axis to z-axis is\", round(be,1), \"degree\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The bending stress at point A is -3342.0 psi\n",
-        "The bending stress at point B is 1820.0 psi\n",
-        "Inclination of neutral axis to z-axis is 79.1 degree\n"
-       ]
-      }
-     ],
-     "prompt_number": 16
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 6.9, page no. 448"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculate magnitude of the moment M\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialization\n",
-      "b = 5                   # in inch\n",
-      "b1 = 4                  # in inch\n",
-      "h = 9                   # in inch\n",
-      "h1 = 7.5                # in inch\n",
-      "sy = 33                 # stress along y axis in ksi\n",
-      "\n",
-      "#Calculations\n",
-      "M = (sy/12.0)*((3*b*h**2)-(b+(2*b1))*(h1**2))  # Bending moment acting in k-in\n",
-      "\n",
-      "#Result\n",
-      "print \"the magnitude of the moment M is\", round(M), \"k-in\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "the magnitude of the moment M is 1330.0 k-in\n"
-       ]
-      }
-     ],
-     "prompt_number": 7
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Testing_the_interface/chapter7.ipynb b/Testing_the_interface/chapter7.ipynb
deleted file mode 100755
index 7c80c103..00000000
--- a/Testing_the_interface/chapter7.ipynb
+++ /dev/null
@@ -1,465 +0,0 @@
-{
- "metadata": {
-  "name": ""
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 7: Analysis of Stress and Strain"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 7.1, page no. 472"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculate stresses acting on an element inclined at 45\u00b0\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "# Let x1, y1 be the transformed direction inclined at 45 deegree to the original\n",
-      "sx = 16000                          # Direct stress in x-direction in psi\n",
-      "sy = 6000                           # Direct stress in y-direction \"\"\n",
-      "txy = 4000                          # Shear stress in y-direction \"\"\n",
-      "tyx = txy                           # Shear stress in x-direction \"\"\n",
-      "t = 45                              # Inclination pf plane in degree \n",
-      "\n",
-      "#calculation\n",
-      "sx1 = (sx+sy)/2 + ((sx-sy)*(math.cos(math.radians(2*t))/2.0)) + txy*math.sin(math.radians(2*t))       # Direct stress in x1-direction in psi\n",
-      "sy1 = (sx+sy)/2 - ((sx-sy)*(math.cos(math.radians(2*t))/2.0)) - txy*math.sin(math.radians(2*t))       # Direct stress in y1-direction in psi\n",
-      "tx1y1 =  - ((sx-sy)*(math.sin(math.radians(2*t))/2.0)) + txy*math.cos(math.radians(2*t))    # Shear stress in psi\n",
-      "\n",
-      "print \"The direct stress on the element in x1-direction is\", sx1, \"psi\"\n",
-      "print \"The direct stress on the element in y1-direction is\", sy1, \"psi\"\n",
-      "print \"The shear stress on the element\", tx1y1, \"psi\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The direct stress on the element in x1-direction is 15000.0 psi\n",
-        "The direct stress on the element in y1-direction is 7000.0 psi\n",
-        "The shear stress on the element -5000.0 psi\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 7.2, page no. 473"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "stresses acting on an element that is oriented at a clockwise 15\u00b0 \n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "# Let x1, y1 be the transformed direction inclined at 15 deegree to the original\n",
-      "sx = -46e06                     # Direct stress in x-direction in Pa\n",
-      "sy = 12e06                      # Direct stress in y-direction \"\"\n",
-      "txy = -19e06                    # Shear stress in y-direction \"\"\n",
-      "t = -15                         # Inclination of plane in degree \n",
-      "\n",
-      "#calculation\n",
-      "sx1 = (sx+sy)/2.0 + ((sx-sy)*(math.cos(math.radians(2*t))/2.0)) + txy*math.sin(math.radians(2*t))   # Direct stress in x1-direction in Pa\n",
-      "sy1 = (sx+sy)/2.0 - ((sx-sy)*(math.cos(math.radians(2*t))/2.0)) - txy*math.sin(math.radians(2*t))   # Direct stress in y1-direction in Pa\n",
-      "tx1y1 = -((sx-sy)*(math.sin(math.radians(2*t))/2.0)) + txy*math.cos(math.radians(2*t))             # Shear stress in Pa\n",
-      "\n",
-      "\n",
-      "print \"The direct stress on the element in x1-direction is\", sx1, \"Pa\"\n",
-      "print \"The direct stress on the element in y1-direction is\", sy1, \"Pa\"\n",
-      "print \"The shear stress on the element\", tx1y1, \"Pa\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The direct stress on the element in x1-direction is -32614736.7097 Pa\n",
-        "The direct stress on the element in y1-direction is -1385263.29025 Pa\n",
-        "The shear stress on the element -30954482.6719 Pa\n"
-       ]
-      }
-     ],
-     "prompt_number": 2
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "example 7.3, page no. 481"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "Calculate shear stress and principal stress\n",
-      "\"\"\"\n",
-      "\n",
-      "import math\n",
-      "\n",
-      "ax = 12300.0\n",
-      "ay = -4200.0\n",
-      "txy = -4700.0\n",
-      "\n",
-      "tan_2p = round((2*txy)/(ax-ay), 4)\n",
-      "\n",
-      "theta_p1 = 150.3\n",
-      "theta_p2 = 330.3\n",
-      "\n",
-      "stress1 = (ax+ay)/2.0\n",
-      "stress2 = (ax-ay)/2.0\n",
-      "a1 = stress1 + math.sqrt((stress2**2.0)+(txy**2.0))\n",
-      "a2 = stress1 - math.sqrt((stress2**2.0)+(txy**2.0))\n",
-      "\n",
-      "#python calculations differ a bit. hence, differences in the answer\n",
-      "print \"Principal stesses are \", round(a1), \"psi and \", round(a2), \" psi\"\n",
-      "\n",
-      "tmax = math.sqrt((stress2**2.0)+(txy**2.0))\n",
-      "print \"Maximum shear stress is \", round(tmax), \" psi\"\n",
-      "\n",
-      "a_aver = (ax+ay)/2.0\n",
-      "\n",
-      "print \"Normal stress acting at maximum shear stress = \", round(a_aver), \"psi\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Principal stesses are  13545.0 psi and  -5445.0  psi\n",
-        "Maximum shear stress is  9495.0  psi\n",
-        "Normal stress acting at maximum shear stress =  4050.0 psi\n"
-       ]
-      }
-     ],
-     "prompt_number": 53
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 7.4, page no. 492"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "stresses acting on an element inclined at 30\u00b0 \n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "sx = 90e06                      # Direct stress in x-direction in Pa\n",
-      "sy = 20e06                      # Direct stress in y-direction in Pa\n",
-      "t = 30                          # Inclination of element in degree\n",
-      "\n",
-      "#calculation\n",
-      "savg = (sx+sy)/2.0                                  # Average in-plane direct stress\n",
-      "txy = 0 \n",
-      "R = math.sqrt(((sx-sy)/2)**2+(txy)**2)              # Radius of mohr circle\n",
-      "\n",
-      "# Point D  at 2t = 60\n",
-      "sx1 = savg + R*math.cos(math.radians(2*t))          # Direct stress at point D \n",
-      "tx1y1 = -R*math.sin(math.radians(2*t))              # shear stress at point D\n",
-      "print \"The direct stress at point D is\", sx1, \"Pa\"\n",
-      "print \"The shear stress at point D is\", tx1y1, \"Pa\"\n",
-      "\n",
-      "# Point D  at 2t = 240\n",
-      "sx2 = savg + R*math.cos(math.radians(90 + t))       # Direct stress at point D \n",
-      "tx2y2 = R*math.sin(math.radians(90 + t))            # shear stress at point D\n",
-      "print \"The direct stress at point D_desh is\", sx2, \"Pa\"\n",
-      "print \"The shear stress at point D_desh is\", tx2y2, \"Pa\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The direct stress at point D is 72500000.0 Pa\n",
-        "The shear stress at point D is -30310889.1325 Pa\n",
-        "The direct stress at point D_desh is 37500000.0 Pa\n",
-        "The shear stress at point D_desh is 30310889.1325 Pa\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 7.5, page no. 494"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "stresses acting on an element, principal stress, max. shear stress\n",
-      "\"\"\"\n",
-      "\n",
-      "import math\n",
-      "import numpy\n",
-      "\n",
-      "#initialisation \n",
-      "sx = 15000                              # Direct stress in x-direction in psi\n",
-      "sy = 5000                               # Direct stress in y-direction \"\"\n",
-      "txy = 4000                              # Shear stress in y-direction \"\"\n",
-      "savg = (sx+sy)/2.0                        # Average in-plane direct stress\n",
-      "sx1 = 15000                             # Stress acting on face at theta = 0 degree\n",
-      "tx1y1 = 4000                            # Stress acting on face at theta = 0 degree\n",
-      "sx1_ = 5000                             \n",
-      "tx1y1_ = -4000                          \n",
-      "\n",
-      "#calculation\n",
-      "R = math.sqrt(((sx-sy)/2)**2+(txy)**2)              # Radius of mohr circle\n",
-      "\n",
-      "# Part (a)\n",
-      "t = 40                                              # Inclination of the plane in degree\n",
-      "f1 = numpy.degrees(numpy.arctan((4000.0/5000.0)))     # Angle between line CD and x1-axis\n",
-      "f2 = 80 - f1                                        # Angle between line CA and x1-axis\n",
-      "\n",
-      "# Point D  \n",
-      "sx1 = savg + R*math.cos(math.radians(f2))       # Direct stress at point D \n",
-      "tx1y1 = -R*math.sin(math.radians(f2))           # shear stress at point D\n",
-      "print \"The shear stress at point D\", round(tx1y1), \"psi\"\n",
-      "\n",
-      "# Point D'  \n",
-      "sx2 = savg - R*math.cos(math.radians(f2))       # Direct stress at point D' \n",
-      "tx2y2 = R*math.sin(math.radians(f2))            # shear stress at point D'\n",
-      "print \"The direct stres at point D_desh\", round(sx2), \"psi\"\n",
-      "\n",
-      "#Part (b)\n",
-      "sp1 = savg + R                                      # Maximum direct stress in mohe circle (at point P1)\n",
-      "tp1 = f1/2                                          # Inclination of plane of maximum direct stress\n",
-      "print \"with angle\", sp1, \"psi The maximum direct stress at P1 is \", round(tp1,2), \"degree\"\n",
-      "sp2 =  savg - R  # Minimum direct stress in mohe circle (at point P2)\n",
-      "tp2 = (f1+180)/2  # Inclination of plane of minimum direct stress\n",
-      "print \"with angle\", sp2, \"psi The maximum direct stress at P2 is \", round(tp2,2), \"degree\"\n",
-      "\n",
-      "# Part (c)\n",
-      "tmax = R                                            # Maximum shear stress in mohe circle\n",
-      "ts1 = -(90 - f1)/2.0                                # Inclination of plane of maximum shear stress\n",
-      "print \"with plane incilation of\", tmax, \"psi The Maximum shear stress is \", round(ts1,2), \"deegree\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The shear stress at point D -4229.0 psi\n",
-        "The direct stres at point D_desh 5193.0 psi\n",
-        "with angle 16403.1242374 psi The maximum direct stress at P1 is  19.33 degree\n",
-        "with angle 3596.87576257 psi The maximum direct stress at P2 is  109.33 degree\n",
-        "with plane incilation of 6403.12423743 psi The Maximum shear stress is  -25.67 deegree\n"
-       ]
-      }
-     ],
-     "prompt_number": 6
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 7.6"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "use Mohr\u2019s circle, to calculate various quantities\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "import numpy\n",
-      "\n",
-      "\n",
-      "sx = -50e06                                 # Direct stress in x-direction in psi\n",
-      "sy = 10e06                                  # Direct stress in y-direction \"\"\n",
-      "txy = -40e06                                # Shear stress in y-direction \"\"\n",
-      "savg = (sx+sy)/2                            # Average in-plane direct stress\n",
-      "sx1 = -50e06\n",
-      "tx1y1 = -40e06                              # Stress acting on face at theta = 0 degree\n",
-      "sx1_ = 10e06\n",
-      "tx1y1_ = 40e06                              # Stress acting on face at theta = 0 degree\n",
-      "\n",
-      "#calculation\n",
-      "R = math.sqrt(((sx-sy)/2)**2+(txy)**2)      # Radius of mohr circle\n",
-      "\n",
-      "# Part (a)\n",
-      "t = 45                                                  # Inclination of the plane in degree\n",
-      "f1 = numpy.degrees(numpy.arctan((40e06/30e06)))       # Angle between line CD and x1-axis\n",
-      "f2 = 90 - f1  # Angle between line CA and x1-axis\n",
-      "\n",
-      "# Point D  \n",
-      "sx1 = savg - R*math.cos(math.radians(f2))           # Direct stress at point D \n",
-      "tx1y1 = R*math.sin(math.radians(f2))                # shear stress at point D\n",
-      "print \"The direct stres at point D\", sx1, \"Pa\"\n",
-      "print \"The shear stress at point D\", tx1y1, \"Pa\"\n",
-      "\n",
-      "# Point D'  \n",
-      "sx2 = savg + R*math.cos(math.radians(f2))           # Direct stress at point D' \n",
-      "tx2y2 = -R*math.sin(math.radians(f2))               # shear stress at point D'\n",
-      "print \"The direct stres at point D_desh\", sx2, \"Pa\"\n",
-      "print \"The shear stress at point D_desh\", tx2y2, \"Pa\"\n",
-      "\n",
-      "#Part (b)\n",
-      "sp1 =  savg + R                                         # Maximum direct stress in mohe circle (at point P1)\n",
-      "tp1 =(f1+180)/2                                         # Inclination of plane of maximum direct stress\n",
-      "print \"with angle\", round(tp1,2), \"degree\", \"The maximum direct stress at P1 is \",  sp1, \"Pa\" \n",
-      "sp2 =  savg - R                                         # Minimum direct stress in mohe circle (at point P2)\n",
-      "tp2 = f1/2                                              # Inclination of plane of minimum direct stress\n",
-      "print \"with angle\", round(tp2,2), \"degree\", \"The maximum direct stress at P2 is \", sp2, \"Pa\"\n",
-      "\n",
-      "# Part (c)\n",
-      "tmax = R                                                # Maximum shear stress in mohe circle\n",
-      "ts1 = (90 + f1)/2                                       # Inclination of plane of maximum shear stress\n",
-      "print \"with plane incilation of\", round(ts1,2), \"degree\", \"The Maximum shear stress is \", tmax, \"Pa\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The direct stres at point D -60000000.0 Pa\n",
-        "The shear stress at point D 30000000.0 Pa\n",
-        "The direct stres at point D_desh 20000000.0 Pa\n",
-        "The shear stress at point D_desh -30000000.0 Pa\n",
-        "with angle 116.57 degree The maximum direct stress at P1 is  30000000.0 Pa\n",
-        "with angle 26.57 degree The maximum direct stress at P2 is  -70000000.0 Pa\n",
-        "with plane incilation of 71.57 degree The Maximum shear stress is  50000000.0 Pa\n"
-       ]
-      }
-     ],
-     "prompt_number": 11
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 7.7, page no. 520"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculate various quantities\n",
-      "\"\"\"\n",
-      "\n",
-      "import math\n",
-      "import numpy\n",
-      "\n",
-      "#initialisation\n",
-      "\n",
-      "ex = 340e-06                            # Strain in x-direction\n",
-      "ey = 110e-06                            # Strain in y-direction\n",
-      "txy = 180e-06                           # shear strain\n",
-      "\n",
-      "\n",
-      "# Part (a)\n",
-      "t = 30                                      # Inclination of the element in degree\n",
-      "ex1 = (ex+ey)/2.0 + ((ex-ey)/2.0)*math.cos(math.radians(2*t)) + (txy/2.0)*(math.sin(math.radians(2*t)))         # Strain in x1 direction (located at 30 degree)\n",
-      "tx1y1 = 2*(-((ex-ey)/2.0)*math.sin(math.radians(2*t)) + (txy/2.0)*(math.cos(math.radians(2*t))))                # Shear starin\n",
-      "ey1 = ex+ey-ex1                             # Strain in y1 direction (located at 30 degree)\n",
-      "print \"Strain in x1 direction (located at 30 degree) is\", round((ex1/1E-6),2),\"* 10^-6\"\n",
-      "print \"shear strain is\", round((tx1y1/1E-6),2),\"* 10^-6\"\n",
-      "print \"Strain in y1 direction (located at 30 degree) is\", ey1\n",
-      "\n",
-      "# Part (b)\n",
-      "e1 = (ex+ey)/2.0 + math.sqrt(((ex-ey)/2.0)**2 + (txy/2.0)**2) # Principle stress\n",
-      "e2 = (ex+ey)/2.0 - math.sqrt(((ex-ey)/2.0)**2 + (txy/2.0)**2) # Principle stress\n",
-      "tp1 = (0.5)*numpy.degrees(numpy.arctan((txy/(ex-ey)))) # Angle to principle stress direction\n",
-      "tp2 = 90 + tp1  # Angle to principle stress direction\n",
-      "e1 = (ex+ey)/2.0 + ((ex-ey)/2.0)*math.cos(math.radians(2*tp1)) + (txy/2.0)*(math.sin(math.radians(2*tp1)))      # Principle stress via another method\n",
-      "e2 = (ex+ey)/2.0 + ((ex-ey)/2.0)*math.cos(math.radians(2*tp2)) + (txy/2.0)*(math.sin(math.radians(2*tp2)))      # Principle stress via another method\n",
-      "print \"with angle\", tp1, \"degree\",\"The Principle stress is \", e1\n",
-      "print \"with angle\",tp2, \"degree\",\"The Principle stress is \",e2\n",
-      "\n",
-      "# Part (c)\n",
-      "tmax = 2*math.sqrt(((ex-ey)/2.0)**2 + (txy/2.0)**2)         # Maxmum shear strain\n",
-      "ts = tp1 + 45                                               # Orientation of element having maximum shear stress \n",
-      "tx1y1_ =  2*( -((ex-ey)/2)*math.sin(math.radians(2*ts)) + (txy/2)*(math.cos(math.radians(2*ts))))  # Shear starin assosiated with ts direction\n",
-      "print \"with angle\",round(ts,2), \"degree\",\"The Maximum shear strain is \",tx1y1_tx1y1_,\n",
-      "eavg = (e1+e2)/2.0                                          # Average atrain\n",
-      "print \"The average strain is\", eavg"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Strain in x1 direction (located at 30 degree) is 360.44 * 10^-6\n",
-        "shear strain is -109.19 * 10^-6\n",
-        "Strain in y1 direction (located at 30 degree) is 8.95577136594e-05\n",
-        "with angle 19.0235212659 degree The Principle stress is  0.000371030818665\n",
-        "with angle 109.023521266 degree The Principle stress is  7.89691813349e-05\n",
-        "with angle 64.02 degree The Maximum shear strain is  -0.00029206163733\n",
-        "The average strain is 0.000225\n"
-       ]
-      }
-     ],
-     "prompt_number": 12
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Testing_the_interface/chapter7_1.ipynb b/Testing_the_interface/chapter7_1.ipynb
deleted file mode 100755
index 7c80c103..00000000
--- a/Testing_the_interface/chapter7_1.ipynb
+++ /dev/null
@@ -1,465 +0,0 @@
-{
- "metadata": {
-  "name": ""
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 7: Analysis of Stress and Strain"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 7.1, page no. 472"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculate stresses acting on an element inclined at 45\u00b0\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "# Let x1, y1 be the transformed direction inclined at 45 deegree to the original\n",
-      "sx = 16000                          # Direct stress in x-direction in psi\n",
-      "sy = 6000                           # Direct stress in y-direction \"\"\n",
-      "txy = 4000                          # Shear stress in y-direction \"\"\n",
-      "tyx = txy                           # Shear stress in x-direction \"\"\n",
-      "t = 45                              # Inclination pf plane in degree \n",
-      "\n",
-      "#calculation\n",
-      "sx1 = (sx+sy)/2 + ((sx-sy)*(math.cos(math.radians(2*t))/2.0)) + txy*math.sin(math.radians(2*t))       # Direct stress in x1-direction in psi\n",
-      "sy1 = (sx+sy)/2 - ((sx-sy)*(math.cos(math.radians(2*t))/2.0)) - txy*math.sin(math.radians(2*t))       # Direct stress in y1-direction in psi\n",
-      "tx1y1 =  - ((sx-sy)*(math.sin(math.radians(2*t))/2.0)) + txy*math.cos(math.radians(2*t))    # Shear stress in psi\n",
-      "\n",
-      "print \"The direct stress on the element in x1-direction is\", sx1, \"psi\"\n",
-      "print \"The direct stress on the element in y1-direction is\", sy1, \"psi\"\n",
-      "print \"The shear stress on the element\", tx1y1, \"psi\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The direct stress on the element in x1-direction is 15000.0 psi\n",
-        "The direct stress on the element in y1-direction is 7000.0 psi\n",
-        "The shear stress on the element -5000.0 psi\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 7.2, page no. 473"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "stresses acting on an element that is oriented at a clockwise 15\u00b0 \n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "# Let x1, y1 be the transformed direction inclined at 15 deegree to the original\n",
-      "sx = -46e06                     # Direct stress in x-direction in Pa\n",
-      "sy = 12e06                      # Direct stress in y-direction \"\"\n",
-      "txy = -19e06                    # Shear stress in y-direction \"\"\n",
-      "t = -15                         # Inclination of plane in degree \n",
-      "\n",
-      "#calculation\n",
-      "sx1 = (sx+sy)/2.0 + ((sx-sy)*(math.cos(math.radians(2*t))/2.0)) + txy*math.sin(math.radians(2*t))   # Direct stress in x1-direction in Pa\n",
-      "sy1 = (sx+sy)/2.0 - ((sx-sy)*(math.cos(math.radians(2*t))/2.0)) - txy*math.sin(math.radians(2*t))   # Direct stress in y1-direction in Pa\n",
-      "tx1y1 = -((sx-sy)*(math.sin(math.radians(2*t))/2.0)) + txy*math.cos(math.radians(2*t))             # Shear stress in Pa\n",
-      "\n",
-      "\n",
-      "print \"The direct stress on the element in x1-direction is\", sx1, \"Pa\"\n",
-      "print \"The direct stress on the element in y1-direction is\", sy1, \"Pa\"\n",
-      "print \"The shear stress on the element\", tx1y1, \"Pa\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The direct stress on the element in x1-direction is -32614736.7097 Pa\n",
-        "The direct stress on the element in y1-direction is -1385263.29025 Pa\n",
-        "The shear stress on the element -30954482.6719 Pa\n"
-       ]
-      }
-     ],
-     "prompt_number": 2
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "example 7.3, page no. 481"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "Calculate shear stress and principal stress\n",
-      "\"\"\"\n",
-      "\n",
-      "import math\n",
-      "\n",
-      "ax = 12300.0\n",
-      "ay = -4200.0\n",
-      "txy = -4700.0\n",
-      "\n",
-      "tan_2p = round((2*txy)/(ax-ay), 4)\n",
-      "\n",
-      "theta_p1 = 150.3\n",
-      "theta_p2 = 330.3\n",
-      "\n",
-      "stress1 = (ax+ay)/2.0\n",
-      "stress2 = (ax-ay)/2.0\n",
-      "a1 = stress1 + math.sqrt((stress2**2.0)+(txy**2.0))\n",
-      "a2 = stress1 - math.sqrt((stress2**2.0)+(txy**2.0))\n",
-      "\n",
-      "#python calculations differ a bit. hence, differences in the answer\n",
-      "print \"Principal stesses are \", round(a1), \"psi and \", round(a2), \" psi\"\n",
-      "\n",
-      "tmax = math.sqrt((stress2**2.0)+(txy**2.0))\n",
-      "print \"Maximum shear stress is \", round(tmax), \" psi\"\n",
-      "\n",
-      "a_aver = (ax+ay)/2.0\n",
-      "\n",
-      "print \"Normal stress acting at maximum shear stress = \", round(a_aver), \"psi\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Principal stesses are  13545.0 psi and  -5445.0  psi\n",
-        "Maximum shear stress is  9495.0  psi\n",
-        "Normal stress acting at maximum shear stress =  4050.0 psi\n"
-       ]
-      }
-     ],
-     "prompt_number": 53
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 7.4, page no. 492"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "stresses acting on an element inclined at 30\u00b0 \n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "sx = 90e06                      # Direct stress in x-direction in Pa\n",
-      "sy = 20e06                      # Direct stress in y-direction in Pa\n",
-      "t = 30                          # Inclination of element in degree\n",
-      "\n",
-      "#calculation\n",
-      "savg = (sx+sy)/2.0                                  # Average in-plane direct stress\n",
-      "txy = 0 \n",
-      "R = math.sqrt(((sx-sy)/2)**2+(txy)**2)              # Radius of mohr circle\n",
-      "\n",
-      "# Point D  at 2t = 60\n",
-      "sx1 = savg + R*math.cos(math.radians(2*t))          # Direct stress at point D \n",
-      "tx1y1 = -R*math.sin(math.radians(2*t))              # shear stress at point D\n",
-      "print \"The direct stress at point D is\", sx1, \"Pa\"\n",
-      "print \"The shear stress at point D is\", tx1y1, \"Pa\"\n",
-      "\n",
-      "# Point D  at 2t = 240\n",
-      "sx2 = savg + R*math.cos(math.radians(90 + t))       # Direct stress at point D \n",
-      "tx2y2 = R*math.sin(math.radians(90 + t))            # shear stress at point D\n",
-      "print \"The direct stress at point D_desh is\", sx2, \"Pa\"\n",
-      "print \"The shear stress at point D_desh is\", tx2y2, \"Pa\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The direct stress at point D is 72500000.0 Pa\n",
-        "The shear stress at point D is -30310889.1325 Pa\n",
-        "The direct stress at point D_desh is 37500000.0 Pa\n",
-        "The shear stress at point D_desh is 30310889.1325 Pa\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 7.5, page no. 494"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "stresses acting on an element, principal stress, max. shear stress\n",
-      "\"\"\"\n",
-      "\n",
-      "import math\n",
-      "import numpy\n",
-      "\n",
-      "#initialisation \n",
-      "sx = 15000                              # Direct stress in x-direction in psi\n",
-      "sy = 5000                               # Direct stress in y-direction \"\"\n",
-      "txy = 4000                              # Shear stress in y-direction \"\"\n",
-      "savg = (sx+sy)/2.0                        # Average in-plane direct stress\n",
-      "sx1 = 15000                             # Stress acting on face at theta = 0 degree\n",
-      "tx1y1 = 4000                            # Stress acting on face at theta = 0 degree\n",
-      "sx1_ = 5000                             \n",
-      "tx1y1_ = -4000                          \n",
-      "\n",
-      "#calculation\n",
-      "R = math.sqrt(((sx-sy)/2)**2+(txy)**2)              # Radius of mohr circle\n",
-      "\n",
-      "# Part (a)\n",
-      "t = 40                                              # Inclination of the plane in degree\n",
-      "f1 = numpy.degrees(numpy.arctan((4000.0/5000.0)))     # Angle between line CD and x1-axis\n",
-      "f2 = 80 - f1                                        # Angle between line CA and x1-axis\n",
-      "\n",
-      "# Point D  \n",
-      "sx1 = savg + R*math.cos(math.radians(f2))       # Direct stress at point D \n",
-      "tx1y1 = -R*math.sin(math.radians(f2))           # shear stress at point D\n",
-      "print \"The shear stress at point D\", round(tx1y1), \"psi\"\n",
-      "\n",
-      "# Point D'  \n",
-      "sx2 = savg - R*math.cos(math.radians(f2))       # Direct stress at point D' \n",
-      "tx2y2 = R*math.sin(math.radians(f2))            # shear stress at point D'\n",
-      "print \"The direct stres at point D_desh\", round(sx2), \"psi\"\n",
-      "\n",
-      "#Part (b)\n",
-      "sp1 = savg + R                                      # Maximum direct stress in mohe circle (at point P1)\n",
-      "tp1 = f1/2                                          # Inclination of plane of maximum direct stress\n",
-      "print \"with angle\", sp1, \"psi The maximum direct stress at P1 is \", round(tp1,2), \"degree\"\n",
-      "sp2 =  savg - R  # Minimum direct stress in mohe circle (at point P2)\n",
-      "tp2 = (f1+180)/2  # Inclination of plane of minimum direct stress\n",
-      "print \"with angle\", sp2, \"psi The maximum direct stress at P2 is \", round(tp2,2), \"degree\"\n",
-      "\n",
-      "# Part (c)\n",
-      "tmax = R                                            # Maximum shear stress in mohe circle\n",
-      "ts1 = -(90 - f1)/2.0                                # Inclination of plane of maximum shear stress\n",
-      "print \"with plane incilation of\", tmax, \"psi The Maximum shear stress is \", round(ts1,2), \"deegree\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The shear stress at point D -4229.0 psi\n",
-        "The direct stres at point D_desh 5193.0 psi\n",
-        "with angle 16403.1242374 psi The maximum direct stress at P1 is  19.33 degree\n",
-        "with angle 3596.87576257 psi The maximum direct stress at P2 is  109.33 degree\n",
-        "with plane incilation of 6403.12423743 psi The Maximum shear stress is  -25.67 deegree\n"
-       ]
-      }
-     ],
-     "prompt_number": 6
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 7.6"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "use Mohr\u2019s circle, to calculate various quantities\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "import numpy\n",
-      "\n",
-      "\n",
-      "sx = -50e06                                 # Direct stress in x-direction in psi\n",
-      "sy = 10e06                                  # Direct stress in y-direction \"\"\n",
-      "txy = -40e06                                # Shear stress in y-direction \"\"\n",
-      "savg = (sx+sy)/2                            # Average in-plane direct stress\n",
-      "sx1 = -50e06\n",
-      "tx1y1 = -40e06                              # Stress acting on face at theta = 0 degree\n",
-      "sx1_ = 10e06\n",
-      "tx1y1_ = 40e06                              # Stress acting on face at theta = 0 degree\n",
-      "\n",
-      "#calculation\n",
-      "R = math.sqrt(((sx-sy)/2)**2+(txy)**2)      # Radius of mohr circle\n",
-      "\n",
-      "# Part (a)\n",
-      "t = 45                                                  # Inclination of the plane in degree\n",
-      "f1 = numpy.degrees(numpy.arctan((40e06/30e06)))       # Angle between line CD and x1-axis\n",
-      "f2 = 90 - f1  # Angle between line CA and x1-axis\n",
-      "\n",
-      "# Point D  \n",
-      "sx1 = savg - R*math.cos(math.radians(f2))           # Direct stress at point D \n",
-      "tx1y1 = R*math.sin(math.radians(f2))                # shear stress at point D\n",
-      "print \"The direct stres at point D\", sx1, \"Pa\"\n",
-      "print \"The shear stress at point D\", tx1y1, \"Pa\"\n",
-      "\n",
-      "# Point D'  \n",
-      "sx2 = savg + R*math.cos(math.radians(f2))           # Direct stress at point D' \n",
-      "tx2y2 = -R*math.sin(math.radians(f2))               # shear stress at point D'\n",
-      "print \"The direct stres at point D_desh\", sx2, \"Pa\"\n",
-      "print \"The shear stress at point D_desh\", tx2y2, \"Pa\"\n",
-      "\n",
-      "#Part (b)\n",
-      "sp1 =  savg + R                                         # Maximum direct stress in mohe circle (at point P1)\n",
-      "tp1 =(f1+180)/2                                         # Inclination of plane of maximum direct stress\n",
-      "print \"with angle\", round(tp1,2), \"degree\", \"The maximum direct stress at P1 is \",  sp1, \"Pa\" \n",
-      "sp2 =  savg - R                                         # Minimum direct stress in mohe circle (at point P2)\n",
-      "tp2 = f1/2                                              # Inclination of plane of minimum direct stress\n",
-      "print \"with angle\", round(tp2,2), \"degree\", \"The maximum direct stress at P2 is \", sp2, \"Pa\"\n",
-      "\n",
-      "# Part (c)\n",
-      "tmax = R                                                # Maximum shear stress in mohe circle\n",
-      "ts1 = (90 + f1)/2                                       # Inclination of plane of maximum shear stress\n",
-      "print \"with plane incilation of\", round(ts1,2), \"degree\", \"The Maximum shear stress is \", tmax, \"Pa\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The direct stres at point D -60000000.0 Pa\n",
-        "The shear stress at point D 30000000.0 Pa\n",
-        "The direct stres at point D_desh 20000000.0 Pa\n",
-        "The shear stress at point D_desh -30000000.0 Pa\n",
-        "with angle 116.57 degree The maximum direct stress at P1 is  30000000.0 Pa\n",
-        "with angle 26.57 degree The maximum direct stress at P2 is  -70000000.0 Pa\n",
-        "with plane incilation of 71.57 degree The Maximum shear stress is  50000000.0 Pa\n"
-       ]
-      }
-     ],
-     "prompt_number": 11
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 7.7, page no. 520"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculate various quantities\n",
-      "\"\"\"\n",
-      "\n",
-      "import math\n",
-      "import numpy\n",
-      "\n",
-      "#initialisation\n",
-      "\n",
-      "ex = 340e-06                            # Strain in x-direction\n",
-      "ey = 110e-06                            # Strain in y-direction\n",
-      "txy = 180e-06                           # shear strain\n",
-      "\n",
-      "\n",
-      "# Part (a)\n",
-      "t = 30                                      # Inclination of the element in degree\n",
-      "ex1 = (ex+ey)/2.0 + ((ex-ey)/2.0)*math.cos(math.radians(2*t)) + (txy/2.0)*(math.sin(math.radians(2*t)))         # Strain in x1 direction (located at 30 degree)\n",
-      "tx1y1 = 2*(-((ex-ey)/2.0)*math.sin(math.radians(2*t)) + (txy/2.0)*(math.cos(math.radians(2*t))))                # Shear starin\n",
-      "ey1 = ex+ey-ex1                             # Strain in y1 direction (located at 30 degree)\n",
-      "print \"Strain in x1 direction (located at 30 degree) is\", round((ex1/1E-6),2),\"* 10^-6\"\n",
-      "print \"shear strain is\", round((tx1y1/1E-6),2),\"* 10^-6\"\n",
-      "print \"Strain in y1 direction (located at 30 degree) is\", ey1\n",
-      "\n",
-      "# Part (b)\n",
-      "e1 = (ex+ey)/2.0 + math.sqrt(((ex-ey)/2.0)**2 + (txy/2.0)**2) # Principle stress\n",
-      "e2 = (ex+ey)/2.0 - math.sqrt(((ex-ey)/2.0)**2 + (txy/2.0)**2) # Principle stress\n",
-      "tp1 = (0.5)*numpy.degrees(numpy.arctan((txy/(ex-ey)))) # Angle to principle stress direction\n",
-      "tp2 = 90 + tp1  # Angle to principle stress direction\n",
-      "e1 = (ex+ey)/2.0 + ((ex-ey)/2.0)*math.cos(math.radians(2*tp1)) + (txy/2.0)*(math.sin(math.radians(2*tp1)))      # Principle stress via another method\n",
-      "e2 = (ex+ey)/2.0 + ((ex-ey)/2.0)*math.cos(math.radians(2*tp2)) + (txy/2.0)*(math.sin(math.radians(2*tp2)))      # Principle stress via another method\n",
-      "print \"with angle\", tp1, \"degree\",\"The Principle stress is \", e1\n",
-      "print \"with angle\",tp2, \"degree\",\"The Principle stress is \",e2\n",
-      "\n",
-      "# Part (c)\n",
-      "tmax = 2*math.sqrt(((ex-ey)/2.0)**2 + (txy/2.0)**2)         # Maxmum shear strain\n",
-      "ts = tp1 + 45                                               # Orientation of element having maximum shear stress \n",
-      "tx1y1_ =  2*( -((ex-ey)/2)*math.sin(math.radians(2*ts)) + (txy/2)*(math.cos(math.radians(2*ts))))  # Shear starin assosiated with ts direction\n",
-      "print \"with angle\",round(ts,2), \"degree\",\"The Maximum shear strain is \",tx1y1_tx1y1_,\n",
-      "eavg = (e1+e2)/2.0                                          # Average atrain\n",
-      "print \"The average strain is\", eavg"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Strain in x1 direction (located at 30 degree) is 360.44 * 10^-6\n",
-        "shear strain is -109.19 * 10^-6\n",
-        "Strain in y1 direction (located at 30 degree) is 8.95577136594e-05\n",
-        "with angle 19.0235212659 degree The Principle stress is  0.000371030818665\n",
-        "with angle 109.023521266 degree The Principle stress is  7.89691813349e-05\n",
-        "with angle 64.02 degree The Maximum shear strain is  -0.00029206163733\n",
-        "The average strain is 0.000225\n"
-       ]
-      }
-     ],
-     "prompt_number": 12
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Testing_the_interface/chapter8.ipynb b/Testing_the_interface/chapter8.ipynb
deleted file mode 100755
index 2e7289e4..00000000
--- a/Testing_the_interface/chapter8.ipynb
+++ /dev/null
@@ -1,524 +0,0 @@
-{
- "metadata": {
-  "name": ""
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 8: Applications of Plane Stress Pressure Vessels Beams and Combined Loadings"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 8.1, page no. 546"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "finding max. permissible pressures at various conditions\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "d = 18                                  # inner idameter of the hemisphere in inch\n",
-      "t = 1.0/4.0                                 # thickness of the hemisphere in inch\n",
-      "\n",
-      "\n",
-      "#calculation\n",
-      "# Part (a)\n",
-      "sa = 14000                                # Allowable tensile stress in Psi\n",
-      "Pa = (2*t*sa)/(d/2.0)                     # Maximum permissible air pressure in Psi\n",
-      "print \"Maximum permissible air pressure in the tank (Part(a)) is\", round(Pa,1), \"psi\"\n",
-      "\n",
-      "# Part (b)\n",
-      "sb = 6000                                  # Allowable shear stress in Psi\n",
-      "Pb = (4*t*sb)/(d/2.0)                      # Maximum permissible air pressure in Psi\n",
-      "print \"Maximum permissible air pressure in the tank (Part(b)) is\", round(Pb,1), \"psi\"\n",
-      "\n",
-      "# Part (c)\n",
-      "e = 0.0003                                # Allowable Strain in Outer sufrface of the hemisphere\n",
-      "E = 29e06                                 # Modulus of epasticity of the steel in Psi\n",
-      "v = 0.28                                  # Poissions's ratio of the steel\n",
-      "Pc = (2*t*E*e)/((d/2.0)*(1-v))            # Maximum permissible air pressure in Psi\n",
-      "print \"Maximum permissible air pressure in the tank (Part(c)) is\", round(Pc,1), \"psi\"\n",
-      "\n",
-      "# Part (d)\n",
-      "Tf = 8100                                 # failure tensile load in lb/in \n",
-      "n = 2.5                                   # Required factor of safetty against failure of the weld\n",
-      "Ta = Tf / n                               # Allowable load in ld/in \n",
-      "sd = (Ta*(1))/(t*(1))                     # Allowable tensile stress in Psi\n",
-      "Pd = (2*t*sd)/(d/2.0)                       # Maximum permissible air pressure in Psi\n",
-      "print \"Maximum permissible air pressure in the tank (Part(d)) is\", round(Pd,1), \"psi\"\n",
-      "\n",
-      "# Part (e)\n",
-      "Pallow = Pb  \n",
-      "print \"Maximum permissible air pressure in the tank (Part(e)) is\", round(Pb,1) ,\"psi\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum permissible air pressure in the tank (Part(a)) is 777.8 psi\n",
-        "Maximum permissible air pressure in the tank (Part(b)) is 666.7 psi\n",
-        "Maximum permissible air pressure in the tank (Part(c)) is 671.3 psi\n",
-        "Maximum permissible air pressure in the tank (Part(d)) is 720.0 psi\n",
-        "Maximum permissible air pressure in the tank (Part(e)) is 666.7 psi\n"
-       ]
-      }
-     ],
-     "prompt_number": 2
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 8.2, page no. 552"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculating various quantities for cylindrical part of vessel\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "a = 55                              # Angle made by helix with longitudinal axis in degree\n",
-      "r = 1.8                             # Inner radius of vessel in m\n",
-      "t = 0.02                            # thickness of vessel in m\n",
-      "E = 200e09                          # Modulus of ealsticity of steel in Pa\n",
-      "v = 0.3                             # Poission's ratio of steel \n",
-      "P = 800e03                          # Pressure inside the tank in Pa\n",
-      "\n",
-      "\n",
-      "#calculation\n",
-      "# Part (a)\n",
-      "s1 = (P*r)/t                        # Circumferential stress in Pa\n",
-      "s2 = (P*r)/(2*t)                    # Longitudinal stress in Pa\n",
-      "\n",
-      "print \"Circumferential stress is \", s1, \"Pa\"\n",
-      "print \"Longitudinal stress is \", s2, \"Pa\"\n",
-      "\n",
-      "# Part (b)\n",
-      "t_max_z = (s1-s2)/2.0               # Maximum inplane shear stress in Pa\n",
-      "t_max = s1/2.0                      # Maximum out of plane shear stress in Pa\n",
-      "\n",
-      "print \"Maximum inplane shear stress is \", t_max_z, \"Pa\"\n",
-      "print \"Maximum inplane shear stress is \", t_max, \"Pa\"\n",
-      "\n",
-      "# Part (c)\n",
-      "e1 = (s1/(2*E))*(2-v)               # Strain in circumferential direction \n",
-      "e2 = (s2/E)*(1-(2*v))               # Strain in longitudinal direction\n",
-      "\n",
-      "print \"Strain in circumferential direction is %e\"%(e1)\n",
-      "print \"Strain in longitudinal direction is \", e2\n",
-      "\n",
-      "# Part (d)\n",
-      "# x1 is the direction along the helix\n",
-      "theta = 90 - a  \n",
-      "sx1 = ((P*r)/(4*t))*(3-math.cos(math.radians(2*theta))) # Stress along x1 direction\n",
-      "tx1y1 = ((P*r)/(4*t))*(math.sin(math.radians(2*theta))) # Shear stress in x1y1 plane\n",
-      "sy1 = s1+s2-sx1  # Stress along y1 direction\n",
-      "\n",
-      "print \"Stress along y1 direction is \", sy1\n",
-      "\n",
-      "# Mohr Circle Method\n",
-      "savg = (s1+s2)/2.0                    # Average stress in Pa\n",
-      "R = (s1 - s2 )/2.0                    # Radius of Mohr's Circle in Pa\n",
-      "sx1_ = savg - R*math.cos(math.radians(2*theta))             # Stress along x1 direction\n",
-      "tx1y1_ = R*math.sin(math.radians(2*theta))                  # Shear stress in x1y1 plane\n",
-      "print \"Stress along x1 direction is \", sx1_, \"Pa\"\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Circumferential stress is  72000000.0 Pa\n",
-        "Longitudinal stress is  36000000.0 Pa\n",
-        "Maximum inplane shear stress is  18000000.0 Pa\n",
-        "Maximum inplane shear stress is  36000000.0 Pa\n",
-        "Strain in circumferential direction is 3.060000e-04\n",
-        "Strain in longitudinal direction is  7.2e-05\n",
-        "Stress along y1 direction is  60156362.5799\n",
-        "Stress along x1 direction is  47843637.4201 Pa\n"
-       ]
-      }
-     ],
-     "prompt_number": 13
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 8.3, page no. 562"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "principal stresses and maximum shear stresses at cross section\n",
-      "\"\"\"\n",
-      "\n",
-      "%pylab inline\n",
-      "from matplotlib import *\n",
-      "from pylab import *\n",
-      "import numpy\n",
-      "\n",
-      "#initialisation\n",
-      "L = 6.0                               # Span of the beam in ft\n",
-      "P = 10800                             # Pressure acting in lb\n",
-      "c = 2.0                               # in ft\n",
-      "b = 2.0                               # Width of cross section of the beam in inch\n",
-      "h = 6.0                               # Height of the cross section of the beam in inch\n",
-      "x = 9.0                               # in inch\n",
-      "\n",
-      "#calculation\n",
-      "Ra = P/3.0                                          # Reaction at point at A\n",
-      "V = Ra                                              # Shear force at section mn \n",
-      "M = Ra*x                                            # Bending moment at the section mn\n",
-      "I = (b*h**3)/12.0                                   # Moment of inertia in in4\n",
-      "y = linspace(-3, 3, 61)\n",
-      "sx = -(M/I)*y                                       # Normal stress on  crossection  mn\n",
-      "Q = (b*(h/2-y))*(y+((((h/2.0)-y)/2.0)))               # First moment of recmath.tangular cross section\n",
-      "txy = (V*Q)/(I*b)                                   # Shear stress acting on x face of the stress element\n",
-      "s1 = (sx/2.0)+numpy.sqrt((sx/2.0)**2+(txy)**2)       # Principal Tesile stress on the cross section\n",
-      "s2 = (sx/2.0)-numpy.sqrt((sx/2.0)**2+(txy)**2)       # Principal Compressive stress on the cross section\n",
-      "tmax = numpy.sqrt((sx/2)**2+(txy)**2)                # Maximum shear stress on the cross section\n",
-      "plot(sx,y,'o',color='c')\n",
-      "plot(txy,y,'+',color='m')\n",
-      "plot(s1,y,'--',color='y')\n",
-      "plot(s2,y,'<',color='k')\n",
-      "plot(tmax,y,label=\"Maximum shear stress on cross section\")\n",
-      "legend()\n",
-      "show()\n",
-      "#print \"Principal Tesile stress on the cross section\", s1, \"psi\"\n",
-      "#print \"Principal Compressive stress on the cross section\", s2, \"psi\"\n",
-      "\n",
-      "# Conclusions \n",
-      "s1_max = 14400.0                            # Maximum tensile stress in Psi\n",
-      "txy_max = 900.0                             # Maximum shear stress in Psi\n",
-      "t_max = 14400.0/2.0                         # Largest shear stress at 45 degree plane"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Populating the interactive namespace from numpy and matplotlib\n"
-       ]
-      },
-      {
-       "output_type": "stream",
-       "stream": "stderr",
-       "text": [
-        "WARNING: pylab import has clobbered these variables: ['power', 'random', 'fft', 'load', 'save', 'linalg', 'info']\n",
-        "`%pylab --no-import-all` prevents importing * from pylab and numpy\n"
-       ]
-      },
-      {
-       "metadata": {},
-       "output_type": "display_data",
-       "png": 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vXMmiMWPq7US/Z88AQkKm0qzZ0Fq/NzUulZjkmDodt7AQ2rXT3uEaHV2nXQgX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\n",
-       "text": [
-        "<matplotlib.figure.Figure at 0x4171710>"
-       ]
-      }
-     ],
-     "prompt_number": 26
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 8.4, page no. 570"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "maximum tensile stress, maximum compressive stress, and maximum shear stress in the shaft.\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "d = 0.05                                # Diameter of shaft in m\n",
-      "T = 2400                                # Torque transmitted by the shaft in N-m\n",
-      "P = 125000                              # Tensile force\n",
-      "\n",
-      "#calculation\n",
-      "s0 = (4*P)/(math.pi*d**2)               # Tensile stress in\n",
-      "t0 = (16*T)/(math.pi*d**3)              # Shear force \n",
-      "# Stresses along x and y direction\n",
-      "sx = 0 \n",
-      "sy = s0 \n",
-      "txy = -t0  \n",
-      "s1 = (sx+sy)/2.0 + math.sqrt(((sx-sy)/2.0)**2 + (txy)**2)   # Maximum tensile stress \n",
-      "s2 = (sx+sy)/2.0 - math.sqrt(((sx-sy)/2.0)**2 + (txy)**2)   # Maximum compressive stress \n",
-      "tmax =  math.sqrt(((sx-sy)/2)**2 + (txy)**2)            # Maximum in plane shear stress \n",
-      "print \"Maximum tensile stress %e\" %s1, \"Pa\"\n",
-      "print \"Maximum compressive stress %e\" %s2, \"Pa\"\n",
-      "print \"Maximum in plane shear stress %e \" %tmax, \"Pa\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum tensile stress 1.346662e+08 Pa\n",
-        "Maximum compressive stress -7.100421e+07 Pa\n",
-        "Maximum in plane shear stress 1.028352e+08  Pa\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 8.5, page no. 573"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculate maximum allowable internal pressure\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "\n",
-      "#initialisation\n",
-      "P = 12                              # Axial load in K\n",
-      "r = 2.1                             # Inner radius of the cylinder in inch\n",
-      "t = 0.15                            # Thickness of the cylinder in inch\n",
-      "ta = 6500                           # Allowable shear stress in Psi\n",
-      "\n",
-      "#calculation\n",
-      "p1 = (ta - 3032)/3.5                # allowable internal pressure\n",
-      "p2 = (ta + 3032)/3.5                # allowable internal pressure\n",
-      "p3 = 6500/7.0                       # allowable internal pressure\n",
-      "\n",
-      "prs_allowable = min(p1,p2,p3)              # Minimum pressure would govern the design\n",
-      "print \"Maximum allowable internal pressure \", round(prs_allowable), \"psi\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum allowable internal pressure  929.0 psi\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 8.6, page no. 574"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "principal stresses and maximum shear stresses\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "d1 = 0.18                                   # Inner diameter of circular pole in m\n",
-      "d2 = 0.22                                   # Outer diameter of circular pole in m\n",
-      "P = 2000                                    # Pressure of wind in Pa\n",
-      "b = 1.5                                     # Distance between centre line of pole and board in m\n",
-      "h = 6.6                                     # Distance between centre line of board and bottom of the ploe in m\n",
-      "\n",
-      "#calculation\n",
-      "W = P*(2*1.2)                               # Force at the midpoint of sign \n",
-      "V = W                                       # Load\n",
-      "T = W*b                                     # Torque acting on the pole\n",
-      "M = W*h                                     # Moment at the bottom of the pole\n",
-      "I = (math.pi/64.0)*(d2**4-d1**4)            # Momet of inertia of cross section of the pole\n",
-      "sa = (M*d2)/(2*I)                           # Tensile stress at A \n",
-      "Ip = (math.pi/32.0)*(d2**4-d1**4)           # Polar momet of inertia of cross section of the pole\n",
-      "t1 = (T*d2)/(2*Ip)                          # Shear stress at A and B\n",
-      "r1 = d1/2.0                                 # Inner radius of circular pole in m\n",
-      "r2 = d2/2.0                                 # Outer radius of circular pole in m\n",
-      "A = math.pi*(r2**2-r1**2)                   # Area of the cross section\n",
-      "t2 = ((4*V)/(3*A))*((r2**2 + r1*r2 +r1**2)/(r2**2+r1**2))  # Shear stress at point B \n",
-      "\n",
-      "# Principle stresses \n",
-      "sxa = 0\n",
-      "sya = sa\n",
-      "txya = t1\n",
-      "sxb = 0\n",
-      "syb = 0\n",
-      "txyb = t1+t2 \n",
-      "\n",
-      "# Stresses at A\n",
-      "s1a = (sxa+sya)/2.0 + math.sqrt(((sxa-sya)/2)**2 + (txya)**2)                 # Maximum tensile stress \n",
-      "s2a = (sxa+sya)/2.0 - math.sqrt(((sxa-sya)/2)**2 + (txya)**2)                 # Maximum compressive stress \n",
-      "tmaxa =  math.sqrt(((sxa-sya)/2)**2 + (txya)**2)                            # Maximum in plane shear stress\n",
-      "\n",
-      "print \"Maximum tensile stress at point A is\", s1a, \"Pa\"\n",
-      "print \"Maximum compressive stress at point A is\", s2a, \"Pa\"\n",
-      "print \"Maximum in plane shear stress at point A is\", tmaxa, \"Pa\"\n",
-      "\n",
-      "# Stress at B \n",
-      "s1b = (sxb+syb)/2.0 + math.sqrt(((sxb-syb)/2)**2 + (txyb)**2)                 # Maximum tensile stress \n",
-      "s2b = (sxb+syb)/2.0 - math.sqrt(((sxb-syb)/2)**2 + (txyb)**2)                 # Maximum compressive stress \n",
-      "tmaxb =  math.sqrt(((sxb-syb)/2.0)**2 + (txyb)**2)                            # Maximum in plane shear stress \n",
-      "print \"Maximum tensile stress at point B is\", s1b, \"Pa\"\n",
-      "print \"Maximum compressive stress at point B is\", s2b, \"Pa\"\n",
-      "print \"Maximum in plane shear stress at point B is\", tmaxb, \"Pa\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum tensile stress at point A is 55613361.197 Pa\n",
-        "Maximum compressive stress at point A is -700178.455718 Pa\n",
-        "Maximum in plane shear stress at point A is 28156769.8263 Pa\n",
-        "Maximum tensile stress at point B is 6999035.59641 Pa\n",
-        "Maximum compressive stress at point B is -6999035.59641 Pa\n",
-        "Maximum in plane shear stress at point B is 6999035.59641 Pa\n"
-       ]
-      }
-     ],
-     "prompt_number": 8
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 8.7, page no. 578"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "principal stresses and maximum shear stresses at points & at the base of the post\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "b = 6                           # Outer dimension of the pole in inch\n",
-      "t = 0.5                         # thickness of the pole\n",
-      "P1 = 20*(6.75*24)               # Load acting at the midpoint of the platform\n",
-      "d = 9                           # Distance between longitudinal axis of the post and midpoint of platform\n",
-      "P2 = 800                        # Load in lb\n",
-      "h = 52                          # Distance between base and point of action of P2\n",
-      "\n",
-      "#calculation\n",
-      "M1 = P1*d                       # Moment due to P1\n",
-      "M2 = P2*h                       # Moment due to P2\n",
-      "A = b**2 - (b-2*t)**2           # Area of the cross section\n",
-      "sp1 = P1/A                      # Comoressive stress due to P1 at A and B\n",
-      "I = (1.0/12.0)*(b**4 - (b-2*t)**4)  # Moment of inertia of the cross section\n",
-      "sm1 = (M1*b)/(2*I)              # Comoressive stress due to M1 at A and B\n",
-      "Aweb = (2*t)*(b-(2*t))          # Area of the web\n",
-      "tp2 = P2/Aweb                   # Shear stress at point B by lpad P2\n",
-      "sm2 = (M2*b)/(2*I)              # Comoressive stress due to M2 at A \n",
-      "sa = sp1+sm1+sm2                # Total Compressive stress at point A\n",
-      "sb = sp1+sm1                    # Total compressive at point B \n",
-      "tb = tp2                        # Shear stress at point B\n",
-      "\n",
-      "# Principle stresses \n",
-      "sxa = 0\n",
-      "sya = -sa\n",
-      "txya = 0\n",
-      "sxb = 0\n",
-      "syb = -sb\n",
-      "txyb = tp2 \n",
-      "\n",
-      "# Stresses at A\n",
-      "s1a = (sxa+sya)/2 + math.sqrt(((sxa-sya)/2)**2 + (txya)**2)             # Maximum tensile stress \n",
-      "s2a = (sxa+sya)/2 - math.sqrt(((sxa-sya)/2)**2 + (txya)**2)             # Maximum compressive stress \n",
-      "tmaxa =  math.sqrt(((sxa-sya)/2)**2 + (txya)**2)                        # Maximum in plane shear stress\n",
-      "print \"Maximum tensile stress at point A is\", s1a,\"Psi\"\n",
-      "print \"Maximum compressive stress at point A is\", round(s2a,2), \"Psi\"\n",
-      "print \"Maximum in plane shear stress at point A is\", round(tmaxa,2), \"Psi\"\n",
-      "\n",
-      "# Stress at B \n",
-      "s1b = (sxb+syb)/2 + math.sqrt(((sxb-syb)/2)**2 + (txyb)**2)             # Maximum tensile stress \n",
-      "s2b = (sxb+syb)/2 - math.sqrt(((sxb-syb)/2)**2 + (txyb)**2)             # Maximum compressive stress \n",
-      "tmaxb =  math.sqrt(((sxb-syb)/2)**2 + (txyb)**2)                        # Maximum in plane shear stress\n",
-      "print \"Maximum tensile stress at point B is\", round(s1b,2), \"Psi\"\n",
-      "print \"Maximum compressive stress at point B is\", round(s2b,2), \"Psi\"\n",
-      "print \"Maximum in plane shear stress at point B is\", round(tmaxb,2), \"Psi\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum tensile stress at point A is 0.0 Psi\n",
-        "Maximum compressive stress at point A is -4090.91 Psi\n",
-        "Maximum in plane shear stress at point A is 2045.45 Psi\n",
-        "Maximum tensile stress at point B is 13.67 Psi\n",
-        "Maximum compressive stress at point B is -1872.69 Psi\n",
-        "Maximum in plane shear stress at point B is 943.18 Psi\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Testing_the_interface/chapter8_1.ipynb b/Testing_the_interface/chapter8_1.ipynb
deleted file mode 100755
index 2e7289e4..00000000
--- a/Testing_the_interface/chapter8_1.ipynb
+++ /dev/null
@@ -1,524 +0,0 @@
-{
- "metadata": {
-  "name": ""
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 8: Applications of Plane Stress Pressure Vessels Beams and Combined Loadings"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 8.1, page no. 546"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "finding max. permissible pressures at various conditions\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "d = 18                                  # inner idameter of the hemisphere in inch\n",
-      "t = 1.0/4.0                                 # thickness of the hemisphere in inch\n",
-      "\n",
-      "\n",
-      "#calculation\n",
-      "# Part (a)\n",
-      "sa = 14000                                # Allowable tensile stress in Psi\n",
-      "Pa = (2*t*sa)/(d/2.0)                     # Maximum permissible air pressure in Psi\n",
-      "print \"Maximum permissible air pressure in the tank (Part(a)) is\", round(Pa,1), \"psi\"\n",
-      "\n",
-      "# Part (b)\n",
-      "sb = 6000                                  # Allowable shear stress in Psi\n",
-      "Pb = (4*t*sb)/(d/2.0)                      # Maximum permissible air pressure in Psi\n",
-      "print \"Maximum permissible air pressure in the tank (Part(b)) is\", round(Pb,1), \"psi\"\n",
-      "\n",
-      "# Part (c)\n",
-      "e = 0.0003                                # Allowable Strain in Outer sufrface of the hemisphere\n",
-      "E = 29e06                                 # Modulus of epasticity of the steel in Psi\n",
-      "v = 0.28                                  # Poissions's ratio of the steel\n",
-      "Pc = (2*t*E*e)/((d/2.0)*(1-v))            # Maximum permissible air pressure in Psi\n",
-      "print \"Maximum permissible air pressure in the tank (Part(c)) is\", round(Pc,1), \"psi\"\n",
-      "\n",
-      "# Part (d)\n",
-      "Tf = 8100                                 # failure tensile load in lb/in \n",
-      "n = 2.5                                   # Required factor of safetty against failure of the weld\n",
-      "Ta = Tf / n                               # Allowable load in ld/in \n",
-      "sd = (Ta*(1))/(t*(1))                     # Allowable tensile stress in Psi\n",
-      "Pd = (2*t*sd)/(d/2.0)                       # Maximum permissible air pressure in Psi\n",
-      "print \"Maximum permissible air pressure in the tank (Part(d)) is\", round(Pd,1), \"psi\"\n",
-      "\n",
-      "# Part (e)\n",
-      "Pallow = Pb  \n",
-      "print \"Maximum permissible air pressure in the tank (Part(e)) is\", round(Pb,1) ,\"psi\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum permissible air pressure in the tank (Part(a)) is 777.8 psi\n",
-        "Maximum permissible air pressure in the tank (Part(b)) is 666.7 psi\n",
-        "Maximum permissible air pressure in the tank (Part(c)) is 671.3 psi\n",
-        "Maximum permissible air pressure in the tank (Part(d)) is 720.0 psi\n",
-        "Maximum permissible air pressure in the tank (Part(e)) is 666.7 psi\n"
-       ]
-      }
-     ],
-     "prompt_number": 2
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 8.2, page no. 552"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculating various quantities for cylindrical part of vessel\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "a = 55                              # Angle made by helix with longitudinal axis in degree\n",
-      "r = 1.8                             # Inner radius of vessel in m\n",
-      "t = 0.02                            # thickness of vessel in m\n",
-      "E = 200e09                          # Modulus of ealsticity of steel in Pa\n",
-      "v = 0.3                             # Poission's ratio of steel \n",
-      "P = 800e03                          # Pressure inside the tank in Pa\n",
-      "\n",
-      "\n",
-      "#calculation\n",
-      "# Part (a)\n",
-      "s1 = (P*r)/t                        # Circumferential stress in Pa\n",
-      "s2 = (P*r)/(2*t)                    # Longitudinal stress in Pa\n",
-      "\n",
-      "print \"Circumferential stress is \", s1, \"Pa\"\n",
-      "print \"Longitudinal stress is \", s2, \"Pa\"\n",
-      "\n",
-      "# Part (b)\n",
-      "t_max_z = (s1-s2)/2.0               # Maximum inplane shear stress in Pa\n",
-      "t_max = s1/2.0                      # Maximum out of plane shear stress in Pa\n",
-      "\n",
-      "print \"Maximum inplane shear stress is \", t_max_z, \"Pa\"\n",
-      "print \"Maximum inplane shear stress is \", t_max, \"Pa\"\n",
-      "\n",
-      "# Part (c)\n",
-      "e1 = (s1/(2*E))*(2-v)               # Strain in circumferential direction \n",
-      "e2 = (s2/E)*(1-(2*v))               # Strain in longitudinal direction\n",
-      "\n",
-      "print \"Strain in circumferential direction is %e\"%(e1)\n",
-      "print \"Strain in longitudinal direction is \", e2\n",
-      "\n",
-      "# Part (d)\n",
-      "# x1 is the direction along the helix\n",
-      "theta = 90 - a  \n",
-      "sx1 = ((P*r)/(4*t))*(3-math.cos(math.radians(2*theta))) # Stress along x1 direction\n",
-      "tx1y1 = ((P*r)/(4*t))*(math.sin(math.radians(2*theta))) # Shear stress in x1y1 plane\n",
-      "sy1 = s1+s2-sx1  # Stress along y1 direction\n",
-      "\n",
-      "print \"Stress along y1 direction is \", sy1\n",
-      "\n",
-      "# Mohr Circle Method\n",
-      "savg = (s1+s2)/2.0                    # Average stress in Pa\n",
-      "R = (s1 - s2 )/2.0                    # Radius of Mohr's Circle in Pa\n",
-      "sx1_ = savg - R*math.cos(math.radians(2*theta))             # Stress along x1 direction\n",
-      "tx1y1_ = R*math.sin(math.radians(2*theta))                  # Shear stress in x1y1 plane\n",
-      "print \"Stress along x1 direction is \", sx1_, \"Pa\"\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Circumferential stress is  72000000.0 Pa\n",
-        "Longitudinal stress is  36000000.0 Pa\n",
-        "Maximum inplane shear stress is  18000000.0 Pa\n",
-        "Maximum inplane shear stress is  36000000.0 Pa\n",
-        "Strain in circumferential direction is 3.060000e-04\n",
-        "Strain in longitudinal direction is  7.2e-05\n",
-        "Stress along y1 direction is  60156362.5799\n",
-        "Stress along x1 direction is  47843637.4201 Pa\n"
-       ]
-      }
-     ],
-     "prompt_number": 13
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 8.3, page no. 562"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "principal stresses and maximum shear stresses at cross section\n",
-      "\"\"\"\n",
-      "\n",
-      "%pylab inline\n",
-      "from matplotlib import *\n",
-      "from pylab import *\n",
-      "import numpy\n",
-      "\n",
-      "#initialisation\n",
-      "L = 6.0                               # Span of the beam in ft\n",
-      "P = 10800                             # Pressure acting in lb\n",
-      "c = 2.0                               # in ft\n",
-      "b = 2.0                               # Width of cross section of the beam in inch\n",
-      "h = 6.0                               # Height of the cross section of the beam in inch\n",
-      "x = 9.0                               # in inch\n",
-      "\n",
-      "#calculation\n",
-      "Ra = P/3.0                                          # Reaction at point at A\n",
-      "V = Ra                                              # Shear force at section mn \n",
-      "M = Ra*x                                            # Bending moment at the section mn\n",
-      "I = (b*h**3)/12.0                                   # Moment of inertia in in4\n",
-      "y = linspace(-3, 3, 61)\n",
-      "sx = -(M/I)*y                                       # Normal stress on  crossection  mn\n",
-      "Q = (b*(h/2-y))*(y+((((h/2.0)-y)/2.0)))               # First moment of recmath.tangular cross section\n",
-      "txy = (V*Q)/(I*b)                                   # Shear stress acting on x face of the stress element\n",
-      "s1 = (sx/2.0)+numpy.sqrt((sx/2.0)**2+(txy)**2)       # Principal Tesile stress on the cross section\n",
-      "s2 = (sx/2.0)-numpy.sqrt((sx/2.0)**2+(txy)**2)       # Principal Compressive stress on the cross section\n",
-      "tmax = numpy.sqrt((sx/2)**2+(txy)**2)                # Maximum shear stress on the cross section\n",
-      "plot(sx,y,'o',color='c')\n",
-      "plot(txy,y,'+',color='m')\n",
-      "plot(s1,y,'--',color='y')\n",
-      "plot(s2,y,'<',color='k')\n",
-      "plot(tmax,y,label=\"Maximum shear stress on cross section\")\n",
-      "legend()\n",
-      "show()\n",
-      "#print \"Principal Tesile stress on the cross section\", s1, \"psi\"\n",
-      "#print \"Principal Compressive stress on the cross section\", s2, \"psi\"\n",
-      "\n",
-      "# Conclusions \n",
-      "s1_max = 14400.0                            # Maximum tensile stress in Psi\n",
-      "txy_max = 900.0                             # Maximum shear stress in Psi\n",
-      "t_max = 14400.0/2.0                         # Largest shear stress at 45 degree plane"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Populating the interactive namespace from numpy and matplotlib\n"
-       ]
-      },
-      {
-       "output_type": "stream",
-       "stream": "stderr",
-       "text": [
-        "WARNING: pylab import has clobbered these variables: ['power', 'random', 'fft', 'load', 'save', 'linalg', 'info']\n",
-        "`%pylab --no-import-all` prevents importing * from pylab and numpy\n"
-       ]
-      },
-      {
-       "metadata": {},
-       "output_type": "display_data",
-       "png": 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vXMmiMWPq7US/Z88AQkKm0qzZ0Fq/NzUulZjkmDodt7AQ2rXT3uEaHV2nXQgX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\n",
-       "text": [
-        "<matplotlib.figure.Figure at 0x4171710>"
-       ]
-      }
-     ],
-     "prompt_number": 26
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 8.4, page no. 570"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "maximum tensile stress, maximum compressive stress, and maximum shear stress in the shaft.\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "d = 0.05                                # Diameter of shaft in m\n",
-      "T = 2400                                # Torque transmitted by the shaft in N-m\n",
-      "P = 125000                              # Tensile force\n",
-      "\n",
-      "#calculation\n",
-      "s0 = (4*P)/(math.pi*d**2)               # Tensile stress in\n",
-      "t0 = (16*T)/(math.pi*d**3)              # Shear force \n",
-      "# Stresses along x and y direction\n",
-      "sx = 0 \n",
-      "sy = s0 \n",
-      "txy = -t0  \n",
-      "s1 = (sx+sy)/2.0 + math.sqrt(((sx-sy)/2.0)**2 + (txy)**2)   # Maximum tensile stress \n",
-      "s2 = (sx+sy)/2.0 - math.sqrt(((sx-sy)/2.0)**2 + (txy)**2)   # Maximum compressive stress \n",
-      "tmax =  math.sqrt(((sx-sy)/2)**2 + (txy)**2)            # Maximum in plane shear stress \n",
-      "print \"Maximum tensile stress %e\" %s1, \"Pa\"\n",
-      "print \"Maximum compressive stress %e\" %s2, \"Pa\"\n",
-      "print \"Maximum in plane shear stress %e \" %tmax, \"Pa\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum tensile stress 1.346662e+08 Pa\n",
-        "Maximum compressive stress -7.100421e+07 Pa\n",
-        "Maximum in plane shear stress 1.028352e+08  Pa\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 8.5, page no. 573"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculate maximum allowable internal pressure\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "\n",
-      "#initialisation\n",
-      "P = 12                              # Axial load in K\n",
-      "r = 2.1                             # Inner radius of the cylinder in inch\n",
-      "t = 0.15                            # Thickness of the cylinder in inch\n",
-      "ta = 6500                           # Allowable shear stress in Psi\n",
-      "\n",
-      "#calculation\n",
-      "p1 = (ta - 3032)/3.5                # allowable internal pressure\n",
-      "p2 = (ta + 3032)/3.5                # allowable internal pressure\n",
-      "p3 = 6500/7.0                       # allowable internal pressure\n",
-      "\n",
-      "prs_allowable = min(p1,p2,p3)              # Minimum pressure would govern the design\n",
-      "print \"Maximum allowable internal pressure \", round(prs_allowable), \"psi\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum allowable internal pressure  929.0 psi\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 8.6, page no. 574"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "principal stresses and maximum shear stresses\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "d1 = 0.18                                   # Inner diameter of circular pole in m\n",
-      "d2 = 0.22                                   # Outer diameter of circular pole in m\n",
-      "P = 2000                                    # Pressure of wind in Pa\n",
-      "b = 1.5                                     # Distance between centre line of pole and board in m\n",
-      "h = 6.6                                     # Distance between centre line of board and bottom of the ploe in m\n",
-      "\n",
-      "#calculation\n",
-      "W = P*(2*1.2)                               # Force at the midpoint of sign \n",
-      "V = W                                       # Load\n",
-      "T = W*b                                     # Torque acting on the pole\n",
-      "M = W*h                                     # Moment at the bottom of the pole\n",
-      "I = (math.pi/64.0)*(d2**4-d1**4)            # Momet of inertia of cross section of the pole\n",
-      "sa = (M*d2)/(2*I)                           # Tensile stress at A \n",
-      "Ip = (math.pi/32.0)*(d2**4-d1**4)           # Polar momet of inertia of cross section of the pole\n",
-      "t1 = (T*d2)/(2*Ip)                          # Shear stress at A and B\n",
-      "r1 = d1/2.0                                 # Inner radius of circular pole in m\n",
-      "r2 = d2/2.0                                 # Outer radius of circular pole in m\n",
-      "A = math.pi*(r2**2-r1**2)                   # Area of the cross section\n",
-      "t2 = ((4*V)/(3*A))*((r2**2 + r1*r2 +r1**2)/(r2**2+r1**2))  # Shear stress at point B \n",
-      "\n",
-      "# Principle stresses \n",
-      "sxa = 0\n",
-      "sya = sa\n",
-      "txya = t1\n",
-      "sxb = 0\n",
-      "syb = 0\n",
-      "txyb = t1+t2 \n",
-      "\n",
-      "# Stresses at A\n",
-      "s1a = (sxa+sya)/2.0 + math.sqrt(((sxa-sya)/2)**2 + (txya)**2)                 # Maximum tensile stress \n",
-      "s2a = (sxa+sya)/2.0 - math.sqrt(((sxa-sya)/2)**2 + (txya)**2)                 # Maximum compressive stress \n",
-      "tmaxa =  math.sqrt(((sxa-sya)/2)**2 + (txya)**2)                            # Maximum in plane shear stress\n",
-      "\n",
-      "print \"Maximum tensile stress at point A is\", s1a, \"Pa\"\n",
-      "print \"Maximum compressive stress at point A is\", s2a, \"Pa\"\n",
-      "print \"Maximum in plane shear stress at point A is\", tmaxa, \"Pa\"\n",
-      "\n",
-      "# Stress at B \n",
-      "s1b = (sxb+syb)/2.0 + math.sqrt(((sxb-syb)/2)**2 + (txyb)**2)                 # Maximum tensile stress \n",
-      "s2b = (sxb+syb)/2.0 - math.sqrt(((sxb-syb)/2)**2 + (txyb)**2)                 # Maximum compressive stress \n",
-      "tmaxb =  math.sqrt(((sxb-syb)/2.0)**2 + (txyb)**2)                            # Maximum in plane shear stress \n",
-      "print \"Maximum tensile stress at point B is\", s1b, \"Pa\"\n",
-      "print \"Maximum compressive stress at point B is\", s2b, \"Pa\"\n",
-      "print \"Maximum in plane shear stress at point B is\", tmaxb, \"Pa\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum tensile stress at point A is 55613361.197 Pa\n",
-        "Maximum compressive stress at point A is -700178.455718 Pa\n",
-        "Maximum in plane shear stress at point A is 28156769.8263 Pa\n",
-        "Maximum tensile stress at point B is 6999035.59641 Pa\n",
-        "Maximum compressive stress at point B is -6999035.59641 Pa\n",
-        "Maximum in plane shear stress at point B is 6999035.59641 Pa\n"
-       ]
-      }
-     ],
-     "prompt_number": 8
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 8.7, page no. 578"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "principal stresses and maximum shear stresses at points & at the base of the post\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "b = 6                           # Outer dimension of the pole in inch\n",
-      "t = 0.5                         # thickness of the pole\n",
-      "P1 = 20*(6.75*24)               # Load acting at the midpoint of the platform\n",
-      "d = 9                           # Distance between longitudinal axis of the post and midpoint of platform\n",
-      "P2 = 800                        # Load in lb\n",
-      "h = 52                          # Distance between base and point of action of P2\n",
-      "\n",
-      "#calculation\n",
-      "M1 = P1*d                       # Moment due to P1\n",
-      "M2 = P2*h                       # Moment due to P2\n",
-      "A = b**2 - (b-2*t)**2           # Area of the cross section\n",
-      "sp1 = P1/A                      # Comoressive stress due to P1 at A and B\n",
-      "I = (1.0/12.0)*(b**4 - (b-2*t)**4)  # Moment of inertia of the cross section\n",
-      "sm1 = (M1*b)/(2*I)              # Comoressive stress due to M1 at A and B\n",
-      "Aweb = (2*t)*(b-(2*t))          # Area of the web\n",
-      "tp2 = P2/Aweb                   # Shear stress at point B by lpad P2\n",
-      "sm2 = (M2*b)/(2*I)              # Comoressive stress due to M2 at A \n",
-      "sa = sp1+sm1+sm2                # Total Compressive stress at point A\n",
-      "sb = sp1+sm1                    # Total compressive at point B \n",
-      "tb = tp2                        # Shear stress at point B\n",
-      "\n",
-      "# Principle stresses \n",
-      "sxa = 0\n",
-      "sya = -sa\n",
-      "txya = 0\n",
-      "sxb = 0\n",
-      "syb = -sb\n",
-      "txyb = tp2 \n",
-      "\n",
-      "# Stresses at A\n",
-      "s1a = (sxa+sya)/2 + math.sqrt(((sxa-sya)/2)**2 + (txya)**2)             # Maximum tensile stress \n",
-      "s2a = (sxa+sya)/2 - math.sqrt(((sxa-sya)/2)**2 + (txya)**2)             # Maximum compressive stress \n",
-      "tmaxa =  math.sqrt(((sxa-sya)/2)**2 + (txya)**2)                        # Maximum in plane shear stress\n",
-      "print \"Maximum tensile stress at point A is\", s1a,\"Psi\"\n",
-      "print \"Maximum compressive stress at point A is\", round(s2a,2), \"Psi\"\n",
-      "print \"Maximum in plane shear stress at point A is\", round(tmaxa,2), \"Psi\"\n",
-      "\n",
-      "# Stress at B \n",
-      "s1b = (sxb+syb)/2 + math.sqrt(((sxb-syb)/2)**2 + (txyb)**2)             # Maximum tensile stress \n",
-      "s2b = (sxb+syb)/2 - math.sqrt(((sxb-syb)/2)**2 + (txyb)**2)             # Maximum compressive stress \n",
-      "tmaxb =  math.sqrt(((sxb-syb)/2)**2 + (txyb)**2)                        # Maximum in plane shear stress\n",
-      "print \"Maximum tensile stress at point B is\", round(s1b,2), \"Psi\"\n",
-      "print \"Maximum compressive stress at point B is\", round(s2b,2), \"Psi\"\n",
-      "print \"Maximum in plane shear stress at point B is\", round(tmaxb,2), \"Psi\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum tensile stress at point A is 0.0 Psi\n",
-        "Maximum compressive stress at point A is -4090.91 Psi\n",
-        "Maximum in plane shear stress at point A is 2045.45 Psi\n",
-        "Maximum tensile stress at point B is 13.67 Psi\n",
-        "Maximum compressive stress at point B is -1872.69 Psi\n",
-        "Maximum in plane shear stress at point B is 943.18 Psi\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Testing_the_interface/chapter8_2.ipynb b/Testing_the_interface/chapter8_2.ipynb
deleted file mode 100755
index 2e7289e4..00000000
--- a/Testing_the_interface/chapter8_2.ipynb
+++ /dev/null
@@ -1,524 +0,0 @@
-{
- "metadata": {
-  "name": ""
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 8: Applications of Plane Stress Pressure Vessels Beams and Combined Loadings"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 8.1, page no. 546"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "finding max. permissible pressures at various conditions\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "d = 18                                  # inner idameter of the hemisphere in inch\n",
-      "t = 1.0/4.0                                 # thickness of the hemisphere in inch\n",
-      "\n",
-      "\n",
-      "#calculation\n",
-      "# Part (a)\n",
-      "sa = 14000                                # Allowable tensile stress in Psi\n",
-      "Pa = (2*t*sa)/(d/2.0)                     # Maximum permissible air pressure in Psi\n",
-      "print \"Maximum permissible air pressure in the tank (Part(a)) is\", round(Pa,1), \"psi\"\n",
-      "\n",
-      "# Part (b)\n",
-      "sb = 6000                                  # Allowable shear stress in Psi\n",
-      "Pb = (4*t*sb)/(d/2.0)                      # Maximum permissible air pressure in Psi\n",
-      "print \"Maximum permissible air pressure in the tank (Part(b)) is\", round(Pb,1), \"psi\"\n",
-      "\n",
-      "# Part (c)\n",
-      "e = 0.0003                                # Allowable Strain in Outer sufrface of the hemisphere\n",
-      "E = 29e06                                 # Modulus of epasticity of the steel in Psi\n",
-      "v = 0.28                                  # Poissions's ratio of the steel\n",
-      "Pc = (2*t*E*e)/((d/2.0)*(1-v))            # Maximum permissible air pressure in Psi\n",
-      "print \"Maximum permissible air pressure in the tank (Part(c)) is\", round(Pc,1), \"psi\"\n",
-      "\n",
-      "# Part (d)\n",
-      "Tf = 8100                                 # failure tensile load in lb/in \n",
-      "n = 2.5                                   # Required factor of safetty against failure of the weld\n",
-      "Ta = Tf / n                               # Allowable load in ld/in \n",
-      "sd = (Ta*(1))/(t*(1))                     # Allowable tensile stress in Psi\n",
-      "Pd = (2*t*sd)/(d/2.0)                       # Maximum permissible air pressure in Psi\n",
-      "print \"Maximum permissible air pressure in the tank (Part(d)) is\", round(Pd,1), \"psi\"\n",
-      "\n",
-      "# Part (e)\n",
-      "Pallow = Pb  \n",
-      "print \"Maximum permissible air pressure in the tank (Part(e)) is\", round(Pb,1) ,\"psi\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum permissible air pressure in the tank (Part(a)) is 777.8 psi\n",
-        "Maximum permissible air pressure in the tank (Part(b)) is 666.7 psi\n",
-        "Maximum permissible air pressure in the tank (Part(c)) is 671.3 psi\n",
-        "Maximum permissible air pressure in the tank (Part(d)) is 720.0 psi\n",
-        "Maximum permissible air pressure in the tank (Part(e)) is 666.7 psi\n"
-       ]
-      }
-     ],
-     "prompt_number": 2
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 8.2, page no. 552"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculating various quantities for cylindrical part of vessel\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "a = 55                              # Angle made by helix with longitudinal axis in degree\n",
-      "r = 1.8                             # Inner radius of vessel in m\n",
-      "t = 0.02                            # thickness of vessel in m\n",
-      "E = 200e09                          # Modulus of ealsticity of steel in Pa\n",
-      "v = 0.3                             # Poission's ratio of steel \n",
-      "P = 800e03                          # Pressure inside the tank in Pa\n",
-      "\n",
-      "\n",
-      "#calculation\n",
-      "# Part (a)\n",
-      "s1 = (P*r)/t                        # Circumferential stress in Pa\n",
-      "s2 = (P*r)/(2*t)                    # Longitudinal stress in Pa\n",
-      "\n",
-      "print \"Circumferential stress is \", s1, \"Pa\"\n",
-      "print \"Longitudinal stress is \", s2, \"Pa\"\n",
-      "\n",
-      "# Part (b)\n",
-      "t_max_z = (s1-s2)/2.0               # Maximum inplane shear stress in Pa\n",
-      "t_max = s1/2.0                      # Maximum out of plane shear stress in Pa\n",
-      "\n",
-      "print \"Maximum inplane shear stress is \", t_max_z, \"Pa\"\n",
-      "print \"Maximum inplane shear stress is \", t_max, \"Pa\"\n",
-      "\n",
-      "# Part (c)\n",
-      "e1 = (s1/(2*E))*(2-v)               # Strain in circumferential direction \n",
-      "e2 = (s2/E)*(1-(2*v))               # Strain in longitudinal direction\n",
-      "\n",
-      "print \"Strain in circumferential direction is %e\"%(e1)\n",
-      "print \"Strain in longitudinal direction is \", e2\n",
-      "\n",
-      "# Part (d)\n",
-      "# x1 is the direction along the helix\n",
-      "theta = 90 - a  \n",
-      "sx1 = ((P*r)/(4*t))*(3-math.cos(math.radians(2*theta))) # Stress along x1 direction\n",
-      "tx1y1 = ((P*r)/(4*t))*(math.sin(math.radians(2*theta))) # Shear stress in x1y1 plane\n",
-      "sy1 = s1+s2-sx1  # Stress along y1 direction\n",
-      "\n",
-      "print \"Stress along y1 direction is \", sy1\n",
-      "\n",
-      "# Mohr Circle Method\n",
-      "savg = (s1+s2)/2.0                    # Average stress in Pa\n",
-      "R = (s1 - s2 )/2.0                    # Radius of Mohr's Circle in Pa\n",
-      "sx1_ = savg - R*math.cos(math.radians(2*theta))             # Stress along x1 direction\n",
-      "tx1y1_ = R*math.sin(math.radians(2*theta))                  # Shear stress in x1y1 plane\n",
-      "print \"Stress along x1 direction is \", sx1_, \"Pa\"\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Circumferential stress is  72000000.0 Pa\n",
-        "Longitudinal stress is  36000000.0 Pa\n",
-        "Maximum inplane shear stress is  18000000.0 Pa\n",
-        "Maximum inplane shear stress is  36000000.0 Pa\n",
-        "Strain in circumferential direction is 3.060000e-04\n",
-        "Strain in longitudinal direction is  7.2e-05\n",
-        "Stress along y1 direction is  60156362.5799\n",
-        "Stress along x1 direction is  47843637.4201 Pa\n"
-       ]
-      }
-     ],
-     "prompt_number": 13
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 8.3, page no. 562"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "principal stresses and maximum shear stresses at cross section\n",
-      "\"\"\"\n",
-      "\n",
-      "%pylab inline\n",
-      "from matplotlib import *\n",
-      "from pylab import *\n",
-      "import numpy\n",
-      "\n",
-      "#initialisation\n",
-      "L = 6.0                               # Span of the beam in ft\n",
-      "P = 10800                             # Pressure acting in lb\n",
-      "c = 2.0                               # in ft\n",
-      "b = 2.0                               # Width of cross section of the beam in inch\n",
-      "h = 6.0                               # Height of the cross section of the beam in inch\n",
-      "x = 9.0                               # in inch\n",
-      "\n",
-      "#calculation\n",
-      "Ra = P/3.0                                          # Reaction at point at A\n",
-      "V = Ra                                              # Shear force at section mn \n",
-      "M = Ra*x                                            # Bending moment at the section mn\n",
-      "I = (b*h**3)/12.0                                   # Moment of inertia in in4\n",
-      "y = linspace(-3, 3, 61)\n",
-      "sx = -(M/I)*y                                       # Normal stress on  crossection  mn\n",
-      "Q = (b*(h/2-y))*(y+((((h/2.0)-y)/2.0)))               # First moment of recmath.tangular cross section\n",
-      "txy = (V*Q)/(I*b)                                   # Shear stress acting on x face of the stress element\n",
-      "s1 = (sx/2.0)+numpy.sqrt((sx/2.0)**2+(txy)**2)       # Principal Tesile stress on the cross section\n",
-      "s2 = (sx/2.0)-numpy.sqrt((sx/2.0)**2+(txy)**2)       # Principal Compressive stress on the cross section\n",
-      "tmax = numpy.sqrt((sx/2)**2+(txy)**2)                # Maximum shear stress on the cross section\n",
-      "plot(sx,y,'o',color='c')\n",
-      "plot(txy,y,'+',color='m')\n",
-      "plot(s1,y,'--',color='y')\n",
-      "plot(s2,y,'<',color='k')\n",
-      "plot(tmax,y,label=\"Maximum shear stress on cross section\")\n",
-      "legend()\n",
-      "show()\n",
-      "#print \"Principal Tesile stress on the cross section\", s1, \"psi\"\n",
-      "#print \"Principal Compressive stress on the cross section\", s2, \"psi\"\n",
-      "\n",
-      "# Conclusions \n",
-      "s1_max = 14400.0                            # Maximum tensile stress in Psi\n",
-      "txy_max = 900.0                             # Maximum shear stress in Psi\n",
-      "t_max = 14400.0/2.0                         # Largest shear stress at 45 degree plane"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Populating the interactive namespace from numpy and matplotlib\n"
-       ]
-      },
-      {
-       "output_type": "stream",
-       "stream": "stderr",
-       "text": [
-        "WARNING: pylab import has clobbered these variables: ['power', 'random', 'fft', 'load', 'save', 'linalg', 'info']\n",
-        "`%pylab --no-import-all` prevents importing * from pylab and numpy\n"
-       ]
-      },
-      {
-       "metadata": {},
-       "output_type": "display_data",
-       "png": 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vXMmiMWPq7US/Z88AQkKm0qzZ0Fq/NzUulZjkmDodt7AQ2rXT3uEaHV2nXQgX\nImu8imoZZvSTJk3iXGYm2T/+qM/oAy5epFVJieT0Ffj69iAn5+c6vdc7zLvOx121Cjp1kgleWJbE\nNS7OVEZ/S0QEtGql27BchHM2O7veRjgBAQPIyfm+xtsbZvK6Hja1bXOglPYD13/9q/bjFcIUmeRd\nXHXtij1LS/9ohXAjwgE4evo0+2b+sVJSfSq19Pe/A3//O2q+vQXaDn/zDRQXw8CBtXqbENWSTL4e\nqZjRh4WFUaqUtu+Nbi3Z6GgahoWR37dvpdwgPjGRLQsX2mHkziMjIQOo/SR/990wdCg89pjlxySc\nk9wMJWrNsF1x//79+eGHHyipsFB4wMWLtI6MZL+RYFhKLatmTtvhY8fgp59g9Wprj1LUR2ZP8o88\n8ggbN26kZcuW7Nu3zxJjElbm5uZGUlKS0VYIt0RE4NWyJfsrZPSAlFqaYE7b4ffegwkTwMfHigMU\n9ZbZ1TUPP/wwW7ZsscRYhA1VXHEqNjYWnxuzTLemTfEaPVq76lRmJgBBS5ZwNi+PrSNG8O3w4Wwd\nMYKpq1axMSnJnqfhsHQfxFYnPx+WL4dJk6w7HlF/mT3J9+7dm4CAAEuMRdhBxTLLAwcO8Nbrr1N4\n/jwUFuJ38SLxiYn1stTywoW1XLv2e63fV5u7XP/zH+jeHcLDa30YIWrEJpl8QkKC/uu4uDji4uJs\ncVhRQ6bKLGMiItiycCFx06YZfa8r5/S5ubvIy9vDTTd1rtH2dWlvsHgxPPec2UMVLiA5OZnk5GSL\n79ci1TUZGRkMGzbMaCYv1TXOoap2xX369CE5OZmBkyezrXnzchk9QLePPnLZ1sXZ2d+Snv5/3Hrr\nr7V+b9qENCKXR5rcZv9+GDAATp6EBlICISqQ6hphUcbaFev+p7127VpObt+O5sgRVKc/FrkOWrKE\ns9evu2zrYl/fnuTnH6Go6Dyeni1r9d6CjOr/xvnwQ3j4YZnghXVJWwNRjrGMfvz48Rw6eBBVUkLA\nxYv0SUysFzm9m5sH/v79uHz5f7V+b3XtDQoLYcUKeOSRuo5OiJox+xpizJgxfPvtt1y6dIk2bdrw\n8ssv8/DDD1tibMJOqmuF8M2bb7Ju3TqenjXL6PtdqSVCs2bDuHRpA0FB46rdtjbtDTZtgqgo+cBV\nWJ/Zk/yqVassMQ7hQEy1Qrhw4QI9e/Zk7969eFWxwrQrtURo3nw4Pj7ta7RtbdobfPopPPSQuaMT\nonoS1wg0Zcj4AAAgAElEQVSjKtbRt2/fHjc3N9LS0vjll1+4fv06IS1aEH5jAtdpuHAh+cOGlXvO\nmSMcD48A/Px6WXSfly7B9u1w330W3a0QRslHPqJamzZtIjMzk7KysnLPN/X3Z96YMbydmEgB4A2c\n9vau1y0RatLeYO1aiI8HPz97jVLUJ9KgTFSruvJK3eubNm3iTOPGbB0xotI+XLnUsipVlVH27w9P\nPQVGvk1C6MmiIcJmTLVAWLt2LT179mT8+PEcO3aMKcOHV4pw6mtLBGNllOfPw2+/aZf4E8IW5Epe\n1FpZWRn/+Mc/+OSTT7h27VqlK/uNSUm8vWGDPsI5n5nJbiPNWZytdXFJyVUaNPCt8fbGruQXL4bk\nZO0qUEKYIjdDCbswVV6pM6Rfv3JRjCu0RCguvsKOHRH86U8ncXdvVOV2FcsodfXyukz+iy/g0Udt\nMmQhAJnkRS1Vt9IUUC6jX7p0KV4VPrDVcabWxdoqmz9x4cI6goKqrn00/IC1IKOgXAllbq62b/x/\n/mPt0QrxB8nkRa3VJqMHXCanDwqaQFbW8hpvXzGT//pr6NEDfGue+AhhNsnkhdmqy+gBl8jpy8oK\n+fnnYLp1+5WGDW+qdvuKmfwjj0DXrjB5sjVHKVyFZPLCIdQkowfXyOnd3LwIDBxHZuYS2rWba3Sb\nqjJ5vz7+bN3qL22Fhc3JJC/MUl1GXzGf13HWnL5160lcuPB5la9XbG2ge3zoEGg00L5mHRKEsBjJ\n5IXZqsrodX1uDPN5HWfN6X18OtC27Qs13l53Vb99u/YmKI3GWiMTwji5khcWo9FoGDlyJEopXnjh\nBQ4dOkRpaanRbXVX54YtEc6XlLDbWOvixESHupqvKf84f/0k/803cPfddh6QqJdkkhcWo5Ri4sSJ\nJvP5ivFNTXJ6Z2tdXHEZQKXguy0hvHDvdUBKa4RtySQvLKa6fH7t2rUsWLCAvXv30r1790rvryqn\nd7bWxYa5fHZyNu4Tw+B9iB4jE7ywPcnkhUUZy+e9vLxISUlh/Pjx+jbFxhjL6R29dXFZWVG12/z8\ns7Y+XvJ4YQ9yJS+sQpfPb9y4kT179pgsr9QxltM7cuviM2feIy9vNzff/EG55w3jmuxvs9lelEOH\nhmVkJ2sqLSoihLXJzVDCqky1Kf7mm2+Mllcaip8yxWFbFxcXX2LHjg7cdlsK3t5tjW6TNiGNqZmR\nTJ4MQ4fadHjCyUmrYeEU6lJeaciRSy09PJrRuvXjnDw5r8ptCjIK2LcPunSx4cCEMCBxjbCJ2pRX\nGnL0Uss2bf7Ojh03Exo6w+jVfEGQD9d2Q2ioTYclhJ5M8sImalJeWRVHbong4dGc4OAnyciYRWTk\ncqB8Jr9rTR43BRdyYnam0YW+hbA2meSFTdS1/YExjtYSoU2b6eW6U5ZrN5zkSWRrr3Ith4WwJZnk\nhc3o8vmRI0eW+zBWl89XVT9f0ZThw0lfuZL0Bx7QPxe0ZAlnr18nZeJE/XO2qqdv0MCXkJApRl/L\nOKXhpj9b9fBCmCSTvLC5uubzOo6e0xs659GQLmF2O7wQMskL26sun69JdFPTnN4eLREMM/mzRxrj\nnnyOjMx8yeSFXcgkL2zOVD5f2+hGx5FaIhhO5nlvXiNqciPCelrtcEKYJHXywi4q1s+3b98eNzc3\n0tLSTLY+qIojtUQ4f/5zCgtPA5Bd7E6zZlY9nBAmyZW8sLtNmzaRmZlJWRVX4zXhSC0RLh3YScaF\npbTc/x7Z+cHkfXiSjEZlEtcIuzC7rcGWLVuYNm0apaWlPProozz77LPlDyBtDUQ1TLU+ePrpp2tU\nVmmMvVoilJUV8Ouv0bRrN5e2re/l/BU3Gje22O5FPWGpudOsSb60tJSbb76Zr7/+muDgYLp3786q\nVavo2LGjxQcqXJ/hZJ+amoqnpyelpaV0795dvyB4bWxMSmLqqlWVSi25fp0sg0qc8JUrWTRmjEUn\n+pycH9i//3769DrN9UI3PDwstmtRTzjEQt47d+4kIiKCsLAwAEaPHs369evLTfJC1IVSqtZ3xlZk\nz1JLP79eNGs2klKggYSiwo7M+vU7c+YMbdq00T8OCQlhx44dlbZLSEjQfx0XF0dcXJw5hxUuyJy2\nB6bYoyWCroRSw+NoUBx/5XfcShtLJi9MSk5OrtNfrNUxa5LX1HAVBMNJXghjLNn2wBRbtETQTeZK\ngZqtaPt8Z9zd6zxkUU9UvACePXu2RfZr1iQfHBzMqVOn9I9PnTpFSEiI2YMS9ZOl2h6YYsuWCBoN\neLopioo0NGxY9zELYQ6zJvnbbruNI0eOkJGRQevWrVmzZg2rVq2y1NhEPWVu2wNTbJ3Te7grCguR\nSV7YjVmTfIMGDfj3v/9NfHw8paWlTJw4UT50FWazVj6vY+2c3rCtgU9xEL8nnCXEv1QyeWEXsvyf\ncEjWqp03xpr19FHNClixzZtu3UCpUo4ff5HQ0Bk0aNDEImMXrkuW/xMuzdiygV5eXqSkpFS7ZGBt\nWXOJQT9VxMWL2q81GneKiy9y+PBjcuEjbEYqeIXTsETtvDHWzOmb+SvOn//jcUTEInbv/hNnz75L\ncPBTFhi9EKbJJC8cVnXZ/Nq1ay0W21iydbFhJu973I09y8rodTRHn8l36rSOlJSeNGrUBX//O8we\nuxCmyCQvHJap2vndu3czfvx4s0sqq2JO62LDD1jbfXaKc+0CCEsI0L/esGE4HTt+woEDo7n11p14\neUnZsbAeyeSFQ9Nl8z/99BOTJk2i8Y1OX1evXq11O+LasFTr4tbeRRw/Xvn5pk3j6dBhMQ0aBFR+\nUQgLkit54fCUUjz66KOsXbuWvLw8mxzTnNbFhnGN376LpPm1JSPhdKUSyubNhyGEtUkJpXAKtiyp\nrEpdSi33P5TG7esiycwEX1+rDk+4GCmhFPWKLUsqq1KXUsvikwVERcHvv1t9eEIYJXGNcFrWKqms\nSl1KLb3DvOniBvv2Qc9q1nktLb1Gfn46jRvfYp0TEPWSTPLCaVi73UFN1KTUMjoVevwSSUZCBlkf\nZ9H2rhYkf+DJX24uNdnWIDc3hf377yMm5hsaNYqyyvhF/SNxjXAaupLKpUuXEhsbi4+Pj/61Cxcu\n8Mgjj9h8TMZKLffEwJftf+Txy2+Q2vEkm32X8csVTbV9a/z9exMe/jp79w6isPCMtYYs6hmZ5IVT\nqZjNt2/fHjc3N9LS0mySy1dUXU6PZyg7Hu3OiVMN+PzLb6vdX1DQQwQHP8nevYMoKcm21rBFPSJx\njXA6ukqbBQsWcPr0acqquHHJFqrL6bOCAA+FiizkX8v2M2pYn2r32abNPygsPMO+ffdwyy1bcHeX\nPsWi7mSSF07FEXL5iirm9BPue4Vblmu/vut/2ok+RZNN4YGafaCq0WiIiFjI2bPvo9HIP1FhHolr\nhFMxlcuDtp+NPbJ5Q5mtz/PxBEiNgeXj4eMJsG/CFdIvBRE/ZQpx06YRP2WKyY6WGo0bwcFP4ubm\nYbNxC9ckN0MJp2V4g1Rqaiqenp6UlpbSvXt3qyyIXFMbk5KYumoVvYq1Swx+PAEC31/O+XXvob7Y\nBY21q1yFr1zJojFjzF59SrgmuRlKCAO6mnlr9rOpqSH9+rFozBgi0tIg7wfiExNprfJR0fmQ+kev\nmur63ghhCRL4CadkKpvXlVNau82BMbq+NZ1oR6Mdbjx4VxgACadXsLvHZfilKfS6qN++AO2V/1uJ\nidWuQFVSksP58/+hdeu/2uhshCuQSV44JVNtiNPS0mjRooVdxmXYhCw7OZuwhDAAMqech9hLsKoN\nlKH/Gzr30iWmrlpF+gMP6PdhrH0xQFlZEadPL6SoKIuwsBetfi7CNUhcI5yWRqNh5MiRPPPMMwQH\nB+Pmpv11tmdJZVWmDB9OePKH0LgEDmvXdw1fsQJVVFRugoeqYxxPzxbExGzn3LkVnDz5mk3GLZyf\nXMkLp+WI5ZSGbYazv80mIyEDgD/HdWPRGJi8+xdKl5bSsecmJo8dy+tVZPIV2xfreHoGEROTRGpq\nH0BDaOg/LH8SwqVIdY1wao7QgrgqaRPSiFweWe65Xbtg7Fg4dAg0mrq1LwYoLDxNamo/wsMXSF96\nF2WpuVMmeeESHLGcMjUulZjkmArjhHbt4IsvICbmj3JLw8gmaMkSuH6dLIPulsbKLYuKLuDh0RSN\nxt36JyNszlJzp8Q1wuXYugVxVbzDvCs9p9HA/ffDf/6jneTr0r5Yx9PTPh8uC+cik7xweo6UzRtm\n8lkfZ+knesOqm9GjYcQIeOUVcHOrWftiqDqnF8IUmeSF0zNVTmnrmnndZJ6dnE0YYfoSSkMxMdCo\nEfzwA9xxR+V9GGtfDNpyy/gpU0zW05eU5OLu3hiNRmOJ0xEuQEoohUtwtBbEuqt5YzQaeOgh+PRT\n46/XZZlBnfT0Zzhy5EmUcrwyUmEfciUvXIYjtSAGTC4S8sAD0KULvPUWNKzQSdicnD48fD779g0l\nLe1hIiM/ki6Wou7VNZ9//jkJCQmkpaXx66+/0q1bN+MHkOoaYQOmcvmoqChiY2OtHtkY5vEZszMI\nmxUGlM/jDQ0apC2nHDeu+n3HTZvGt8OHV3q+y/LltPL1LRfh3NWnB/v3j8DNrSFRUatwc6v8AbBw\nfHavrunSpQtffPEFjz/+uNmDEMJcjtDmoKqWBlX5619h0aKaTfJV5fRHT59m38yZ+sfpK1eyCBgU\nt4GDBx9k376hdO78pSw8Uo/VOZOPjIykQ4cOlhyLEGZxpjYHAEOHam+KOny4+m2N5fQNFy4kf1j5\nG6F0LRHc3DyJilpFYOCDuLl5WXLYwsnYJLBLSEjQfx0XF0dcXJwtDivqGXuXUlbV0qCquMbTE8aP\nhw8+gPnzTe/bWE5/2tub/dHRlbbVlVpqNO4EBU2o28kIm0tOTrbKjXsmM/kBAwaQlZVV6fm5c+cy\n7MYVRN++fVmwYIFk8sIhVNXmwFa5PPwx2VcX1wAcOwaxsXDyZOUPYKtT15YIwjnYJJPftm2b2QcQ\nwpZ0pZQjR45k3bp1PP/886Snp9u0/bCp8smK2rWD22+H1avh4Ydrd5wpw4eTvnJlpZYIZ69fJ2Xi\nRP1zFVsXK6Wkjr4esUhcI1fqwpE4QimlqfLJip58EmbNggkTtDX0NVWXUkulytizZwBt284kIKBv\nzQ8mnFadJ/kvvviCKVOmcPHiRYYMGULXrl3ZvHmzJccmRK3ZK5evVD5JGNnJ2VXm8YbuugumTIGf\nf4aePWt33Nq2RNBo3GjbdiYHDvyF9u3/TcuW99fugMLpSBdK4XLsmcvXJo83tGgR/PijtnGZOWqa\n008b3gX/hrNp0+ZZQkImm3dQYRWykLcQVbBni4Pa5PGGHnkEtm+HEyfMO35NWyJMXrWTK/n/4uzZ\ndzh27Dm5EHNhcs+zcEn2zOVrk8frNGmizeT//W94/fW6H7s2Of1biYl8+foPZGVV0URHuASZ5IXL\nsXUub04eb2jKFOjWDWbOBD+/uo+nNjm9h0dz2rT5W90PJhyeZPLCJdkrlze25F9tPPCAthXx9OmW\nG5PU0zsnyeSFMMFeuXxBhnlLe0yfDgsXQmGhhQZE3VoXy4WZ65C4Rrgse+Tyxpb8q42YGOjUCVau\n1H4Yawm1racf3PcOdu/uw003/ZOAALmyd3YS1wiXZCqXDwoKIjMz02LH0mXyBRkFZH2cVW2L4ep8\n8w08/jgcPAjuVlqju7rWxa1anmXUbZto4DmZ+H6vWWcQwiSJa4QwQdd6eOnSpcTGxuLl9Ucnxvz8\nfIseyz/On7CEMLzDvAmbpV3yLywhrE4TPEBcHDRvDuvWWXSY5ZhqXbx1xAg+7vU0T3q/x9Vr77H1\nm/FyoebEZJIX9YIzTVIaDTz/PMydC9Yadk1aF5+kLY83Wc7F7P+RljZelhR0UpLJC5dkKq7x9rbc\nSkkVyyeDxgeRkZBR56hGZ8gQbSnll1/C3XdbarQG+69h6+IrNGXZDyPp96ceaDRyTeiMJJMXLsuW\nZZR1bWdgyrp1MG8e/Ppr7RqX1ZWUWjoWyeSFqIYtyyjr2s7AlHvv1ZZSbtpk8V0bVZdSS+H4JK4R\nLs2WZZTmxDPGuLnBSy/B7NkweLD1r+ZrW2oZf8etNGhgxq25wiZkkhcuy9rtDSzVzsCUkSPh5Ze1\nV/NDhlhklybVvCWCYt++Yfj7xxEWliB5vQOTn4xwWRXLKH18fPSvXbhwgUfMvNtIVzrpH+dvkdJJ\nY9zctFfyL71kvUobU6oqtcy9dJmXP+vA9ykf8v7Km9mYZKNMSdSaTPLCpdkil7dGHm/o3nu1E3xi\nolUPY5SpnD5xyIM82mw5p0PCOH95ApuSPrf9AEW1JK4RLs8Wubyl83hDGo32av755+Gee7RX97ZS\nXU5fjCdzeZ4Hm6/gvusTKSm5iwYNmthugKJaUkIpXJq12htYupVBdZTSLg04eTKMHWvx3ddKVS0R\n7vxiIW4qVEotLcRSc6dcyQuXpsvlBw8ezPz580lNTaXwRotHc9ob6CbzjIQMfR5vTRqN9g7Yv/4V\nRo0CDw+rHs6kqnL6H/fnkT/zjzr79Bsxj0z09iWZvKhXnPmvyr594aabwIpL1NZITVoiwI1Syw0b\nbDk0YYRcyQuXZo32BtZqZVATc+dqP4gdNw4MioVsqqYtEQAC/M5RWJiJl1cr2w5S6EkmL1yetdob\nWKOVQU2MGgW33grPPWfTw5pUVUuEqT9Pp190Gqt3DuXS5RaS09eCtDUQooasVUZp7dLJqsyZAwsW\nwOXLdjm8UVWVWq7ZGcJ8n+ncH7eZ4hH+0hLBDiSuEfWCtcoorR3PGNOhA9x3nza6mT/f5oc3ylSp\nZRZwltb8kxfZ/kB/3k5cL1fzNiSTvHB5lmxvYItWBjUxa5Z2mcCnn4awMJsd1iRTLRHSieBJ3mUW\ns8kPqPtC56L2JJMX9UJVuXxda+Xtlccbmj0bDh/WrgfriIzn9IpuHy2V1sU1IJm8ELWgy+V/+ukn\nJk2aROPGjYG618rbK4839MwzkJwMu3bZeyTGGc/pP5TWxTYmcY2oFwwz+b179+qv5M1ZJcoeebyh\nxo0hIQH+7/+0i3/bYmGR2qht62K5mreOOk/y06dP56uvvsLT05Pw8HCWLVuGn5/0lhaOx1QmHxlZ\n83zYUfJ4Qw8/DG+9BevXg5FOA3ZXk9bFndlHfNdtlJbm4+7e0JbDqxfqnMlv27aN/v374+bmxnM3\nCnZfffXVygeQTF44AEtm8o6QxxvauhWeegr27wdPT3uPxjRjOb03+cxNn0Rg03xW7xxK4bVGktPj\nAJn8gAEDcLvRDi82NpbTp0+bPRghrMWSmbwj5PGGBg6E9u3hnXfsPZLqGcvp/Zes4F9fxfBlwHAe\nil/P2RHtJae3IItk8kuXLmXMmDGW2JUQVmHpTN7eeXxF8+dDnz7adgfNm9t7NFWrOqefxmognXBm\nM4sPHniMtxM31PureUswGdcMGDCArKysSs/PnTuXYTeaEc2ZM4eUlBTWrVtn/AAaDbNmzdI/jouL\nIy4uzsxhC1FzpjL5mrY2sHVr4bp4+mltS2JnuKI3VLF1cWvO0IxLsDyFVr6+9abUMjk5meTkZP3j\n2bNnWySuMatOfvny5SxZsoTt27dXeUUkmbxwBFVl8m5ubvTu3bvcPy5TMhIyABwmjzd06RJ07Ajb\nt0OXLvYeTc1V1fem4SuvkD9zpv5x+MqVLBozxqUnekN2z+S3bNnC66+/zvr1680qQxPCFjQaDSNH\njuSZZ54hODhY/3mSNVaJspdmzeDFF+Fvf7PPerB1Ja2LravOmfzkyZMpKipiwIABAPzpT3/i3Xff\ntdjAhLAkc1ob2LO1cG098QS8/752Pdh777X3aGqmpq2L23OYApzo/14OQtoaiHrD3DJKRyudrMrX\nX8Njj2lLKhs6adl5xQinAcW8y5NkHy4j+UA81/B0+Zze7nGNEM7G3DJKRyudrMqdd0LXro7TobIu\nKkY4JXgwZ1k3ilQhdw/fTtrwHtISoYakrYGoNyxRRulo8UxVFizQLiwyfjyEhtp7NLVntNSyAGbe\n/Cmj+Jx3eZJXmMluaYlQLZnkRb1Q19YGjtjKoCbCwmDyZG0Ts88/t/do6sZ4SwQNn3M/R4lgEu/x\nNP+mwH5DdAqSyYt6w5xM3lnyeEP5+dqe84sXw436CKdWMafXUIbCjW4ffeSSrYslkxeilszJ5J0l\njzfUsCEsXKi9Saqw0N6jMV/FnF7hRtCSJdK6uBpyJS/qjaoy+cDAQKN3dhty1JLJ6igFw4ZBr16O\ntfB3XW1MSuLtDRv+yOkzM9k9aZLBFgrQEJ+YyJaFC+0zSAux1Nwpk7yoF+rS2iA7OZus5Vl4h3lr\n83gHbGVQE+npEBsLv/0GbdvaezSWVbElwij+Q1Mu88vHngQ28XfqCMdSc6d88CrqBY1Gw0cffcTg\nwYMrZfJpaWm0aNGi0nv84/zL5fDOlMcbCg+HqVNh2jT44gt7j8ayvCrcsfw/4nmBOUTFHSGh7Udc\noSkA6TdiHmeb6C1BMnlRb9SH1gZVmT5de3PUxo32HollVczpr+LHy4tasdsrlsU8Tmf2AfW7JYJc\nyYt6o6atDSqWTQIUZBToSyedkbc3/Pvf2rYHffuCj4+9R2QZRlsieDVkedDfOMgvzGYWC5nG99xR\nb0stJZMX9UptyiidsWyyOqNHQ7t2MHeuvUdiPYallkFkUogXV2jqdKWWUkIpRB3UpozSGcsmq/Pm\nm7BkiTa6cVWGEU4WrbhC03pdailxjahXatvawFnjmaq0agUJCTBpEiQng5sLXuZVvfrU1HLbpdeT\nlggyyYt6oyatDZy1jUFtPPEEfPIJLFsGEyfaezTWYbwlgpYbpdzDer5iaL3I6SWTF/VKTTN5V8zj\nDe3Zo2118Pvv0LKlvUdjfYY5vTf5PM9cmnGJ/66+GXfPNg6Z00smL0Qd1DSTd8U83lB0NEyYoF1F\nqj4wzOkLaMhLvEzKL948PWwzV0aEuHROL3GNqFdqk8m7SjxTlVmztGvB/u9/EB9v79FYl7GcPiWz\nPTt7TOBF/slmBvEx410yp5dJXtQb1WXy9SGPN9SoEbz3njaj//137WNXZiyn/5ZbeJzFjGSd/nlX\ny+klkxf1SnWZvG5Sz0jIcNk8vqJx47S5/IIF9h6JbVVsXazjKPX0kskLUQfVZfKunsUb8+absHIl\n/PqrvUdiWxVbIgAuWU8vcY2oV2qaybtiPFOV5s21V/ETJ8KuXeDpae8R2UZ19fQBXKYUd6fP6SWu\nEfWGqUy+ReMWfDfyO7I+znLalsLmUAqGDIGePWHmTHuPxn4MWxcP4SseZAUv8xINlu+kla+vTSMc\naTUsRC1VbDecmppK4Y0lk4rci/AO8yZsVli9yeINaTTaZQK7dYMRIyAqyt4jsg/D1sUbGcoVApjD\nC3zeugWrBi4GNIBztS6WTF7UW/IXZnlt2sDLL2tjm9JSe4/GPirm9D/xZ/6+9DZ69yrkZV6iMdq/\nAJ2pdbFM8qLe0MU1jzzyCDt27KCoqEj/mkeJBxmzMyjIKCAjIaNefgAL8Pjj2kz+rbfsPRL7GNKv\nH4vGjCE+MZE+iYnEJybSqKgZU32WcJ6WDGKzfltnKbWUTF7UK6ZKKH9+/Od6GdVUdPQo9OgBv/wC\nERH2Ho39lS+11K4hC9YvtZQSSiHqoDathuuriAh44QVtbFMPFs2qVvkIRzvBO1OppVzJi3qlqhLK\nwMBA0lan1ZtqmuqUlkLv3jB2LDz9tL1HY38bk5J4e8OGP0otMzPZPWkSAJ4UUoQXAPGJiWxZuNAi\nx7T7lfyLL75IdHQ0MTEx9O/fn1OnTpk9GGeUnJxs7yFYlSudn2Em/8svv+gneIAw77BybQ1cgTk/\nO3d3WLpU23v+2DGLDcmibPm7OaRfP7YsXEjywoVsWbgQ31atANBQxjs8xX18DiiHzOnrPMn/4x//\nYM+ePaSmpjJ8+HBmz55tyXE5DVeaBI1xpfPTlVAuXbqU2NhYPNw99K+dKDxBWEKYS13Jm/uzi4yE\nGTPg4YcdM7ax5++mrtRS4cZMXqEv3zCHFyjNO0v8lCnETZtG/JQpDhHf1HmSb9Kkif7rvLw8mjdv\nbpEBCWFNhpl8l1ZdJJOvxrRpUFIC77xj75E4FsOc/hxBTGURl/deYerdX3F2RHuHyunNuhnqhRde\n4NNPP8XHx4dffvnFUmMSwmrKZfJn91JSVgJUvfxffefurl1BqmdPGDwYwsPtPSLHYKwlQlLmLfx4\ny0PMYjZP8i4XaOkQLRFMfvA6YMAAsrKyKj0/d+5chg0bpn/86quvcujQIZYtW1b5ABqNhYYqhBD1\niyU+eLVIdc3JkycZPHgwv//+u9kDEkIIYTl1zuSPHDmi/3r9+vV07drVIgMSQghhOXW+kr/vvvs4\ndOgQ7u7uhIeH895779GyPqwILIQQTqTOV/Jr165l+PDhKKVIT09nzJgx5Wrl582bR/v27YmMjGTr\n1q3653/77Te6dOlC+/btmXqjbzNAYWEhf/nLX2jfvj09evTgxIkTdR2axUyfPp2OHTsSHR3NiBEj\nyMnJ0b/mCuf3+eef06lTJ9zd3UlJSSn3miucnylbtmwhMjKS9u3b89prr9l7ODXyyCOPEBgYSJcu\nXfTPXb58mQEDBtChQwcGDhxIdvYfdf61/Rna26lTp+jbty+dOnWic+fOvHWjgY6rnGNBQQGxsbHE\nxMQQFRXFjBkzABucnzLD1atX9V+/9dZbauLEiUoppfbv36+io6NVUVGROn78uAoPD1dlZWVKKaW6\nd++uduzYoZRSatCgQWrz5s1KKaXeeecdNWnSJKWUUqtXr1Z/+ctfzBmaRWzdulWVlpYqpZR69tln\n1bPPPquUcp3zO3jwoDp06JCKi4tTv/32m/55Vzm/qpSUlKjw8HB1/PhxVVRUpKKjo9WBAwfsPaxq\nfbAuLEcAAARPSURBVPfddyolJUV17txZ/9z06dPVa6+9ppRS6tVXXzXrd9TeMjMz1e7du5VSSuXm\n5qoOHTqoAwcOuNQ5Xrt2TSmlVHFxsYqNjVXff/+91c/PrN41VdXKr1+/njFjxuDh4UFYWBgRERHs\n2LGDzMxMcnNzuf322wF46KGHSExMBGDDhg2MHz8egJEjR7J9+3ZzhmYRAwYMwM1N+y2KjY3l9OnT\ngOucX2RkJB06dKj0vKucX1V27txJREQEYWFheHh4MHr0aNavX2/vYVWrd+/eBAQElHvO8Ps+fvx4\n/c+jLj9DewsKCiImJgaAxo0b07FjR86cOeNS5+jj4wNAUVERpaWlBAQEWP38zG5Q9sILLxAaGsry\n5cv1f36cPXuWkJAQ/TYhISGcOXOm0vPBwcGcOXMGgDNnztCmTRsAGjRogJ+fH5cvXzZ3eBazdOlS\nBg8eDLjm+Rly9fMzHCv8cX7O6Ny5cwQGBgLa/jvnzp0D6vYzdCQZGRns3r2b2NhYlzrHsrIyYmJi\nCAwM1EdT1j6/am+Gqq5Wfs6cOcyZM4dXX32VadOmGa2Vd2Q1uRdgzpw5eHp6MnbsWFsPz2w1vdeh\nPnHVezc0Go1LnFteXh4jR45k0aJF5dICcP5zdHNzIzU1lZycHOLj4/nmm2/KvW6N86t2kt+2bVuN\ndjR27Fj9lW5wcHC5D2FPnz5NSEgIwcHB+sjD8Hnde06ePEnr1q0pKSkhJyeHpk2b1upk6qK681u+\nfDmbNm0qFz+40vkZ40znVxcVz+/UqVPlroycSWBgIFlZWQQFBZGZmamvcKvNzzA4ONjm465KcXEx\nI0eOZNy4cQy/sdaqq50jgJ+fH0OGDOG3336z+vmZFddUVSt/9913s3r1aoqKijh+/DhHjhzh9ttv\nJygoCF9fX3bs2IFSik8//ZR77rlH/56PP/4Y0Fbu9O/f35yhWcSWLVt4/fXXWb9+fbnb3l3l/Awp\ng0paVzw/Q7fddhtHjhwhIyODoqIi1qxZw913323vYdWJ4ff9448/1k+MtfkZ6t5jb+pGl9CoqCim\nTZumf95VzvHixYv6ypn8/Hy2bdtG165drX9+5nxSPHLkSNW5c2cVHR2tRowYoc6dO6d/bc6cOSo8\nPFzdfPPNasuWLfrnd+3apTp37qzCw8PV5MmT9c8XFBSoUaNGqYiICBUbG6uOHz9uztAsIiIiQoWG\nhqqYmBgVExOjrx5RyjXO77///a8KCQlR3t7eKjAwUN11113611zh/EzZtGmT6tChgwoPD1dz5861\n93BqZPTo0apVq1bKw8NDhYSEqKVLl6pLly6p/v37q/bt26sBAwaoK1eu6Lev7c/Q3r7//nul0WhU\ndHS0/t/c5s2bXeYc9+7dq7p27aqio6NVly5d1L/+9S+llLL6+Vl90RAhhBD2I8v/CSGEC5NJXggh\nXJhM8kII4cJkkhdCCBcmk7wQQrgwmeSFEMKF/T+EGvw6HyMN5gAAAABJRU5ErkJggg==\n",
-       "text": [
-        "<matplotlib.figure.Figure at 0x4171710>"
-       ]
-      }
-     ],
-     "prompt_number": 26
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 8.4, page no. 570"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "maximum tensile stress, maximum compressive stress, and maximum shear stress in the shaft.\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "d = 0.05                                # Diameter of shaft in m\n",
-      "T = 2400                                # Torque transmitted by the shaft in N-m\n",
-      "P = 125000                              # Tensile force\n",
-      "\n",
-      "#calculation\n",
-      "s0 = (4*P)/(math.pi*d**2)               # Tensile stress in\n",
-      "t0 = (16*T)/(math.pi*d**3)              # Shear force \n",
-      "# Stresses along x and y direction\n",
-      "sx = 0 \n",
-      "sy = s0 \n",
-      "txy = -t0  \n",
-      "s1 = (sx+sy)/2.0 + math.sqrt(((sx-sy)/2.0)**2 + (txy)**2)   # Maximum tensile stress \n",
-      "s2 = (sx+sy)/2.0 - math.sqrt(((sx-sy)/2.0)**2 + (txy)**2)   # Maximum compressive stress \n",
-      "tmax =  math.sqrt(((sx-sy)/2)**2 + (txy)**2)            # Maximum in plane shear stress \n",
-      "print \"Maximum tensile stress %e\" %s1, \"Pa\"\n",
-      "print \"Maximum compressive stress %e\" %s2, \"Pa\"\n",
-      "print \"Maximum in plane shear stress %e \" %tmax, \"Pa\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum tensile stress 1.346662e+08 Pa\n",
-        "Maximum compressive stress -7.100421e+07 Pa\n",
-        "Maximum in plane shear stress 1.028352e+08  Pa\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 8.5, page no. 573"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculate maximum allowable internal pressure\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "\n",
-      "#initialisation\n",
-      "P = 12                              # Axial load in K\n",
-      "r = 2.1                             # Inner radius of the cylinder in inch\n",
-      "t = 0.15                            # Thickness of the cylinder in inch\n",
-      "ta = 6500                           # Allowable shear stress in Psi\n",
-      "\n",
-      "#calculation\n",
-      "p1 = (ta - 3032)/3.5                # allowable internal pressure\n",
-      "p2 = (ta + 3032)/3.5                # allowable internal pressure\n",
-      "p3 = 6500/7.0                       # allowable internal pressure\n",
-      "\n",
-      "prs_allowable = min(p1,p2,p3)              # Minimum pressure would govern the design\n",
-      "print \"Maximum allowable internal pressure \", round(prs_allowable), \"psi\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum allowable internal pressure  929.0 psi\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 8.6, page no. 574"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "principal stresses and maximum shear stresses\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "d1 = 0.18                                   # Inner diameter of circular pole in m\n",
-      "d2 = 0.22                                   # Outer diameter of circular pole in m\n",
-      "P = 2000                                    # Pressure of wind in Pa\n",
-      "b = 1.5                                     # Distance between centre line of pole and board in m\n",
-      "h = 6.6                                     # Distance between centre line of board and bottom of the ploe in m\n",
-      "\n",
-      "#calculation\n",
-      "W = P*(2*1.2)                               # Force at the midpoint of sign \n",
-      "V = W                                       # Load\n",
-      "T = W*b                                     # Torque acting on the pole\n",
-      "M = W*h                                     # Moment at the bottom of the pole\n",
-      "I = (math.pi/64.0)*(d2**4-d1**4)            # Momet of inertia of cross section of the pole\n",
-      "sa = (M*d2)/(2*I)                           # Tensile stress at A \n",
-      "Ip = (math.pi/32.0)*(d2**4-d1**4)           # Polar momet of inertia of cross section of the pole\n",
-      "t1 = (T*d2)/(2*Ip)                          # Shear stress at A and B\n",
-      "r1 = d1/2.0                                 # Inner radius of circular pole in m\n",
-      "r2 = d2/2.0                                 # Outer radius of circular pole in m\n",
-      "A = math.pi*(r2**2-r1**2)                   # Area of the cross section\n",
-      "t2 = ((4*V)/(3*A))*((r2**2 + r1*r2 +r1**2)/(r2**2+r1**2))  # Shear stress at point B \n",
-      "\n",
-      "# Principle stresses \n",
-      "sxa = 0\n",
-      "sya = sa\n",
-      "txya = t1\n",
-      "sxb = 0\n",
-      "syb = 0\n",
-      "txyb = t1+t2 \n",
-      "\n",
-      "# Stresses at A\n",
-      "s1a = (sxa+sya)/2.0 + math.sqrt(((sxa-sya)/2)**2 + (txya)**2)                 # Maximum tensile stress \n",
-      "s2a = (sxa+sya)/2.0 - math.sqrt(((sxa-sya)/2)**2 + (txya)**2)                 # Maximum compressive stress \n",
-      "tmaxa =  math.sqrt(((sxa-sya)/2)**2 + (txya)**2)                            # Maximum in plane shear stress\n",
-      "\n",
-      "print \"Maximum tensile stress at point A is\", s1a, \"Pa\"\n",
-      "print \"Maximum compressive stress at point A is\", s2a, \"Pa\"\n",
-      "print \"Maximum in plane shear stress at point A is\", tmaxa, \"Pa\"\n",
-      "\n",
-      "# Stress at B \n",
-      "s1b = (sxb+syb)/2.0 + math.sqrt(((sxb-syb)/2)**2 + (txyb)**2)                 # Maximum tensile stress \n",
-      "s2b = (sxb+syb)/2.0 - math.sqrt(((sxb-syb)/2)**2 + (txyb)**2)                 # Maximum compressive stress \n",
-      "tmaxb =  math.sqrt(((sxb-syb)/2.0)**2 + (txyb)**2)                            # Maximum in plane shear stress \n",
-      "print \"Maximum tensile stress at point B is\", s1b, \"Pa\"\n",
-      "print \"Maximum compressive stress at point B is\", s2b, \"Pa\"\n",
-      "print \"Maximum in plane shear stress at point B is\", tmaxb, \"Pa\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum tensile stress at point A is 55613361.197 Pa\n",
-        "Maximum compressive stress at point A is -700178.455718 Pa\n",
-        "Maximum in plane shear stress at point A is 28156769.8263 Pa\n",
-        "Maximum tensile stress at point B is 6999035.59641 Pa\n",
-        "Maximum compressive stress at point B is -6999035.59641 Pa\n",
-        "Maximum in plane shear stress at point B is 6999035.59641 Pa\n"
-       ]
-      }
-     ],
-     "prompt_number": 8
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 8.7, page no. 578"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "principal stresses and maximum shear stresses at points & at the base of the post\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "b = 6                           # Outer dimension of the pole in inch\n",
-      "t = 0.5                         # thickness of the pole\n",
-      "P1 = 20*(6.75*24)               # Load acting at the midpoint of the platform\n",
-      "d = 9                           # Distance between longitudinal axis of the post and midpoint of platform\n",
-      "P2 = 800                        # Load in lb\n",
-      "h = 52                          # Distance between base and point of action of P2\n",
-      "\n",
-      "#calculation\n",
-      "M1 = P1*d                       # Moment due to P1\n",
-      "M2 = P2*h                       # Moment due to P2\n",
-      "A = b**2 - (b-2*t)**2           # Area of the cross section\n",
-      "sp1 = P1/A                      # Comoressive stress due to P1 at A and B\n",
-      "I = (1.0/12.0)*(b**4 - (b-2*t)**4)  # Moment of inertia of the cross section\n",
-      "sm1 = (M1*b)/(2*I)              # Comoressive stress due to M1 at A and B\n",
-      "Aweb = (2*t)*(b-(2*t))          # Area of the web\n",
-      "tp2 = P2/Aweb                   # Shear stress at point B by lpad P2\n",
-      "sm2 = (M2*b)/(2*I)              # Comoressive stress due to M2 at A \n",
-      "sa = sp1+sm1+sm2                # Total Compressive stress at point A\n",
-      "sb = sp1+sm1                    # Total compressive at point B \n",
-      "tb = tp2                        # Shear stress at point B\n",
-      "\n",
-      "# Principle stresses \n",
-      "sxa = 0\n",
-      "sya = -sa\n",
-      "txya = 0\n",
-      "sxb = 0\n",
-      "syb = -sb\n",
-      "txyb = tp2 \n",
-      "\n",
-      "# Stresses at A\n",
-      "s1a = (sxa+sya)/2 + math.sqrt(((sxa-sya)/2)**2 + (txya)**2)             # Maximum tensile stress \n",
-      "s2a = (sxa+sya)/2 - math.sqrt(((sxa-sya)/2)**2 + (txya)**2)             # Maximum compressive stress \n",
-      "tmaxa =  math.sqrt(((sxa-sya)/2)**2 + (txya)**2)                        # Maximum in plane shear stress\n",
-      "print \"Maximum tensile stress at point A is\", s1a,\"Psi\"\n",
-      "print \"Maximum compressive stress at point A is\", round(s2a,2), \"Psi\"\n",
-      "print \"Maximum in plane shear stress at point A is\", round(tmaxa,2), \"Psi\"\n",
-      "\n",
-      "# Stress at B \n",
-      "s1b = (sxb+syb)/2 + math.sqrt(((sxb-syb)/2)**2 + (txyb)**2)             # Maximum tensile stress \n",
-      "s2b = (sxb+syb)/2 - math.sqrt(((sxb-syb)/2)**2 + (txyb)**2)             # Maximum compressive stress \n",
-      "tmaxb =  math.sqrt(((sxb-syb)/2)**2 + (txyb)**2)                        # Maximum in plane shear stress\n",
-      "print \"Maximum tensile stress at point B is\", round(s1b,2), \"Psi\"\n",
-      "print \"Maximum compressive stress at point B is\", round(s2b,2), \"Psi\"\n",
-      "print \"Maximum in plane shear stress at point B is\", round(tmaxb,2), \"Psi\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum tensile stress at point A is 0.0 Psi\n",
-        "Maximum compressive stress at point A is -4090.91 Psi\n",
-        "Maximum in plane shear stress at point A is 2045.45 Psi\n",
-        "Maximum tensile stress at point B is 13.67 Psi\n",
-        "Maximum compressive stress at point B is -1872.69 Psi\n",
-        "Maximum in plane shear stress at point B is 943.18 Psi\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Testing_the_interface/chapter8_3.ipynb b/Testing_the_interface/chapter8_3.ipynb
deleted file mode 100755
index 2e7289e4..00000000
--- a/Testing_the_interface/chapter8_3.ipynb
+++ /dev/null
@@ -1,524 +0,0 @@
-{
- "metadata": {
-  "name": ""
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 8: Applications of Plane Stress Pressure Vessels Beams and Combined Loadings"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 8.1, page no. 546"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "finding max. permissible pressures at various conditions\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "d = 18                                  # inner idameter of the hemisphere in inch\n",
-      "t = 1.0/4.0                                 # thickness of the hemisphere in inch\n",
-      "\n",
-      "\n",
-      "#calculation\n",
-      "# Part (a)\n",
-      "sa = 14000                                # Allowable tensile stress in Psi\n",
-      "Pa = (2*t*sa)/(d/2.0)                     # Maximum permissible air pressure in Psi\n",
-      "print \"Maximum permissible air pressure in the tank (Part(a)) is\", round(Pa,1), \"psi\"\n",
-      "\n",
-      "# Part (b)\n",
-      "sb = 6000                                  # Allowable shear stress in Psi\n",
-      "Pb = (4*t*sb)/(d/2.0)                      # Maximum permissible air pressure in Psi\n",
-      "print \"Maximum permissible air pressure in the tank (Part(b)) is\", round(Pb,1), \"psi\"\n",
-      "\n",
-      "# Part (c)\n",
-      "e = 0.0003                                # Allowable Strain in Outer sufrface of the hemisphere\n",
-      "E = 29e06                                 # Modulus of epasticity of the steel in Psi\n",
-      "v = 0.28                                  # Poissions's ratio of the steel\n",
-      "Pc = (2*t*E*e)/((d/2.0)*(1-v))            # Maximum permissible air pressure in Psi\n",
-      "print \"Maximum permissible air pressure in the tank (Part(c)) is\", round(Pc,1), \"psi\"\n",
-      "\n",
-      "# Part (d)\n",
-      "Tf = 8100                                 # failure tensile load in lb/in \n",
-      "n = 2.5                                   # Required factor of safetty against failure of the weld\n",
-      "Ta = Tf / n                               # Allowable load in ld/in \n",
-      "sd = (Ta*(1))/(t*(1))                     # Allowable tensile stress in Psi\n",
-      "Pd = (2*t*sd)/(d/2.0)                       # Maximum permissible air pressure in Psi\n",
-      "print \"Maximum permissible air pressure in the tank (Part(d)) is\", round(Pd,1), \"psi\"\n",
-      "\n",
-      "# Part (e)\n",
-      "Pallow = Pb  \n",
-      "print \"Maximum permissible air pressure in the tank (Part(e)) is\", round(Pb,1) ,\"psi\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum permissible air pressure in the tank (Part(a)) is 777.8 psi\n",
-        "Maximum permissible air pressure in the tank (Part(b)) is 666.7 psi\n",
-        "Maximum permissible air pressure in the tank (Part(c)) is 671.3 psi\n",
-        "Maximum permissible air pressure in the tank (Part(d)) is 720.0 psi\n",
-        "Maximum permissible air pressure in the tank (Part(e)) is 666.7 psi\n"
-       ]
-      }
-     ],
-     "prompt_number": 2
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 8.2, page no. 552"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculating various quantities for cylindrical part of vessel\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "a = 55                              # Angle made by helix with longitudinal axis in degree\n",
-      "r = 1.8                             # Inner radius of vessel in m\n",
-      "t = 0.02                            # thickness of vessel in m\n",
-      "E = 200e09                          # Modulus of ealsticity of steel in Pa\n",
-      "v = 0.3                             # Poission's ratio of steel \n",
-      "P = 800e03                          # Pressure inside the tank in Pa\n",
-      "\n",
-      "\n",
-      "#calculation\n",
-      "# Part (a)\n",
-      "s1 = (P*r)/t                        # Circumferential stress in Pa\n",
-      "s2 = (P*r)/(2*t)                    # Longitudinal stress in Pa\n",
-      "\n",
-      "print \"Circumferential stress is \", s1, \"Pa\"\n",
-      "print \"Longitudinal stress is \", s2, \"Pa\"\n",
-      "\n",
-      "# Part (b)\n",
-      "t_max_z = (s1-s2)/2.0               # Maximum inplane shear stress in Pa\n",
-      "t_max = s1/2.0                      # Maximum out of plane shear stress in Pa\n",
-      "\n",
-      "print \"Maximum inplane shear stress is \", t_max_z, \"Pa\"\n",
-      "print \"Maximum inplane shear stress is \", t_max, \"Pa\"\n",
-      "\n",
-      "# Part (c)\n",
-      "e1 = (s1/(2*E))*(2-v)               # Strain in circumferential direction \n",
-      "e2 = (s2/E)*(1-(2*v))               # Strain in longitudinal direction\n",
-      "\n",
-      "print \"Strain in circumferential direction is %e\"%(e1)\n",
-      "print \"Strain in longitudinal direction is \", e2\n",
-      "\n",
-      "# Part (d)\n",
-      "# x1 is the direction along the helix\n",
-      "theta = 90 - a  \n",
-      "sx1 = ((P*r)/(4*t))*(3-math.cos(math.radians(2*theta))) # Stress along x1 direction\n",
-      "tx1y1 = ((P*r)/(4*t))*(math.sin(math.radians(2*theta))) # Shear stress in x1y1 plane\n",
-      "sy1 = s1+s2-sx1  # Stress along y1 direction\n",
-      "\n",
-      "print \"Stress along y1 direction is \", sy1\n",
-      "\n",
-      "# Mohr Circle Method\n",
-      "savg = (s1+s2)/2.0                    # Average stress in Pa\n",
-      "R = (s1 - s2 )/2.0                    # Radius of Mohr's Circle in Pa\n",
-      "sx1_ = savg - R*math.cos(math.radians(2*theta))             # Stress along x1 direction\n",
-      "tx1y1_ = R*math.sin(math.radians(2*theta))                  # Shear stress in x1y1 plane\n",
-      "print \"Stress along x1 direction is \", sx1_, \"Pa\"\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Circumferential stress is  72000000.0 Pa\n",
-        "Longitudinal stress is  36000000.0 Pa\n",
-        "Maximum inplane shear stress is  18000000.0 Pa\n",
-        "Maximum inplane shear stress is  36000000.0 Pa\n",
-        "Strain in circumferential direction is 3.060000e-04\n",
-        "Strain in longitudinal direction is  7.2e-05\n",
-        "Stress along y1 direction is  60156362.5799\n",
-        "Stress along x1 direction is  47843637.4201 Pa\n"
-       ]
-      }
-     ],
-     "prompt_number": 13
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 8.3, page no. 562"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "principal stresses and maximum shear stresses at cross section\n",
-      "\"\"\"\n",
-      "\n",
-      "%pylab inline\n",
-      "from matplotlib import *\n",
-      "from pylab import *\n",
-      "import numpy\n",
-      "\n",
-      "#initialisation\n",
-      "L = 6.0                               # Span of the beam in ft\n",
-      "P = 10800                             # Pressure acting in lb\n",
-      "c = 2.0                               # in ft\n",
-      "b = 2.0                               # Width of cross section of the beam in inch\n",
-      "h = 6.0                               # Height of the cross section of the beam in inch\n",
-      "x = 9.0                               # in inch\n",
-      "\n",
-      "#calculation\n",
-      "Ra = P/3.0                                          # Reaction at point at A\n",
-      "V = Ra                                              # Shear force at section mn \n",
-      "M = Ra*x                                            # Bending moment at the section mn\n",
-      "I = (b*h**3)/12.0                                   # Moment of inertia in in4\n",
-      "y = linspace(-3, 3, 61)\n",
-      "sx = -(M/I)*y                                       # Normal stress on  crossection  mn\n",
-      "Q = (b*(h/2-y))*(y+((((h/2.0)-y)/2.0)))               # First moment of recmath.tangular cross section\n",
-      "txy = (V*Q)/(I*b)                                   # Shear stress acting on x face of the stress element\n",
-      "s1 = (sx/2.0)+numpy.sqrt((sx/2.0)**2+(txy)**2)       # Principal Tesile stress on the cross section\n",
-      "s2 = (sx/2.0)-numpy.sqrt((sx/2.0)**2+(txy)**2)       # Principal Compressive stress on the cross section\n",
-      "tmax = numpy.sqrt((sx/2)**2+(txy)**2)                # Maximum shear stress on the cross section\n",
-      "plot(sx,y,'o',color='c')\n",
-      "plot(txy,y,'+',color='m')\n",
-      "plot(s1,y,'--',color='y')\n",
-      "plot(s2,y,'<',color='k')\n",
-      "plot(tmax,y,label=\"Maximum shear stress on cross section\")\n",
-      "legend()\n",
-      "show()\n",
-      "#print \"Principal Tesile stress on the cross section\", s1, \"psi\"\n",
-      "#print \"Principal Compressive stress on the cross section\", s2, \"psi\"\n",
-      "\n",
-      "# Conclusions \n",
-      "s1_max = 14400.0                            # Maximum tensile stress in Psi\n",
-      "txy_max = 900.0                             # Maximum shear stress in Psi\n",
-      "t_max = 14400.0/2.0                         # Largest shear stress at 45 degree plane"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Populating the interactive namespace from numpy and matplotlib\n"
-       ]
-      },
-      {
-       "output_type": "stream",
-       "stream": "stderr",
-       "text": [
-        "WARNING: pylab import has clobbered these variables: ['power', 'random', 'fft', 'load', 'save', 'linalg', 'info']\n",
-        "`%pylab --no-import-all` prevents importing * from pylab and numpy\n"
-       ]
-      },
-      {
-       "metadata": {},
-       "output_type": "display_data",
-       "png": 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vXMmiMWPq7US/Z88AQkKm0qzZ0Fq/NzUulZjkmDodt7AQ2rXT3uEaHV2nXQgX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\n",
-       "text": [
-        "<matplotlib.figure.Figure at 0x4171710>"
-       ]
-      }
-     ],
-     "prompt_number": 26
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 8.4, page no. 570"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "maximum tensile stress, maximum compressive stress, and maximum shear stress in the shaft.\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "d = 0.05                                # Diameter of shaft in m\n",
-      "T = 2400                                # Torque transmitted by the shaft in N-m\n",
-      "P = 125000                              # Tensile force\n",
-      "\n",
-      "#calculation\n",
-      "s0 = (4*P)/(math.pi*d**2)               # Tensile stress in\n",
-      "t0 = (16*T)/(math.pi*d**3)              # Shear force \n",
-      "# Stresses along x and y direction\n",
-      "sx = 0 \n",
-      "sy = s0 \n",
-      "txy = -t0  \n",
-      "s1 = (sx+sy)/2.0 + math.sqrt(((sx-sy)/2.0)**2 + (txy)**2)   # Maximum tensile stress \n",
-      "s2 = (sx+sy)/2.0 - math.sqrt(((sx-sy)/2.0)**2 + (txy)**2)   # Maximum compressive stress \n",
-      "tmax =  math.sqrt(((sx-sy)/2)**2 + (txy)**2)            # Maximum in plane shear stress \n",
-      "print \"Maximum tensile stress %e\" %s1, \"Pa\"\n",
-      "print \"Maximum compressive stress %e\" %s2, \"Pa\"\n",
-      "print \"Maximum in plane shear stress %e \" %tmax, \"Pa\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum tensile stress 1.346662e+08 Pa\n",
-        "Maximum compressive stress -7.100421e+07 Pa\n",
-        "Maximum in plane shear stress 1.028352e+08  Pa\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 8.5, page no. 573"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "calculate maximum allowable internal pressure\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "\n",
-      "#initialisation\n",
-      "P = 12                              # Axial load in K\n",
-      "r = 2.1                             # Inner radius of the cylinder in inch\n",
-      "t = 0.15                            # Thickness of the cylinder in inch\n",
-      "ta = 6500                           # Allowable shear stress in Psi\n",
-      "\n",
-      "#calculation\n",
-      "p1 = (ta - 3032)/3.5                # allowable internal pressure\n",
-      "p2 = (ta + 3032)/3.5                # allowable internal pressure\n",
-      "p3 = 6500/7.0                       # allowable internal pressure\n",
-      "\n",
-      "prs_allowable = min(p1,p2,p3)              # Minimum pressure would govern the design\n",
-      "print \"Maximum allowable internal pressure \", round(prs_allowable), \"psi\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum allowable internal pressure  929.0 psi\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 8.6, page no. 574"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "principal stresses and maximum shear stresses\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "d1 = 0.18                                   # Inner diameter of circular pole in m\n",
-      "d2 = 0.22                                   # Outer diameter of circular pole in m\n",
-      "P = 2000                                    # Pressure of wind in Pa\n",
-      "b = 1.5                                     # Distance between centre line of pole and board in m\n",
-      "h = 6.6                                     # Distance between centre line of board and bottom of the ploe in m\n",
-      "\n",
-      "#calculation\n",
-      "W = P*(2*1.2)                               # Force at the midpoint of sign \n",
-      "V = W                                       # Load\n",
-      "T = W*b                                     # Torque acting on the pole\n",
-      "M = W*h                                     # Moment at the bottom of the pole\n",
-      "I = (math.pi/64.0)*(d2**4-d1**4)            # Momet of inertia of cross section of the pole\n",
-      "sa = (M*d2)/(2*I)                           # Tensile stress at A \n",
-      "Ip = (math.pi/32.0)*(d2**4-d1**4)           # Polar momet of inertia of cross section of the pole\n",
-      "t1 = (T*d2)/(2*Ip)                          # Shear stress at A and B\n",
-      "r1 = d1/2.0                                 # Inner radius of circular pole in m\n",
-      "r2 = d2/2.0                                 # Outer radius of circular pole in m\n",
-      "A = math.pi*(r2**2-r1**2)                   # Area of the cross section\n",
-      "t2 = ((4*V)/(3*A))*((r2**2 + r1*r2 +r1**2)/(r2**2+r1**2))  # Shear stress at point B \n",
-      "\n",
-      "# Principle stresses \n",
-      "sxa = 0\n",
-      "sya = sa\n",
-      "txya = t1\n",
-      "sxb = 0\n",
-      "syb = 0\n",
-      "txyb = t1+t2 \n",
-      "\n",
-      "# Stresses at A\n",
-      "s1a = (sxa+sya)/2.0 + math.sqrt(((sxa-sya)/2)**2 + (txya)**2)                 # Maximum tensile stress \n",
-      "s2a = (sxa+sya)/2.0 - math.sqrt(((sxa-sya)/2)**2 + (txya)**2)                 # Maximum compressive stress \n",
-      "tmaxa =  math.sqrt(((sxa-sya)/2)**2 + (txya)**2)                            # Maximum in plane shear stress\n",
-      "\n",
-      "print \"Maximum tensile stress at point A is\", s1a, \"Pa\"\n",
-      "print \"Maximum compressive stress at point A is\", s2a, \"Pa\"\n",
-      "print \"Maximum in plane shear stress at point A is\", tmaxa, \"Pa\"\n",
-      "\n",
-      "# Stress at B \n",
-      "s1b = (sxb+syb)/2.0 + math.sqrt(((sxb-syb)/2)**2 + (txyb)**2)                 # Maximum tensile stress \n",
-      "s2b = (sxb+syb)/2.0 - math.sqrt(((sxb-syb)/2)**2 + (txyb)**2)                 # Maximum compressive stress \n",
-      "tmaxb =  math.sqrt(((sxb-syb)/2.0)**2 + (txyb)**2)                            # Maximum in plane shear stress \n",
-      "print \"Maximum tensile stress at point B is\", s1b, \"Pa\"\n",
-      "print \"Maximum compressive stress at point B is\", s2b, \"Pa\"\n",
-      "print \"Maximum in plane shear stress at point B is\", tmaxb, \"Pa\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum tensile stress at point A is 55613361.197 Pa\n",
-        "Maximum compressive stress at point A is -700178.455718 Pa\n",
-        "Maximum in plane shear stress at point A is 28156769.8263 Pa\n",
-        "Maximum tensile stress at point B is 6999035.59641 Pa\n",
-        "Maximum compressive stress at point B is -6999035.59641 Pa\n",
-        "Maximum in plane shear stress at point B is 6999035.59641 Pa\n"
-       ]
-      }
-     ],
-     "prompt_number": 8
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 8.7, page no. 578"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\"\"\"\n",
-      "principal stresses and maximum shear stresses at points & at the base of the post\n",
-      "\"\"\"\n",
-      "\n",
-      "import math \n",
-      "\n",
-      "#initialisation\n",
-      "b = 6                           # Outer dimension of the pole in inch\n",
-      "t = 0.5                         # thickness of the pole\n",
-      "P1 = 20*(6.75*24)               # Load acting at the midpoint of the platform\n",
-      "d = 9                           # Distance between longitudinal axis of the post and midpoint of platform\n",
-      "P2 = 800                        # Load in lb\n",
-      "h = 52                          # Distance between base and point of action of P2\n",
-      "\n",
-      "#calculation\n",
-      "M1 = P1*d                       # Moment due to P1\n",
-      "M2 = P2*h                       # Moment due to P2\n",
-      "A = b**2 - (b-2*t)**2           # Area of the cross section\n",
-      "sp1 = P1/A                      # Comoressive stress due to P1 at A and B\n",
-      "I = (1.0/12.0)*(b**4 - (b-2*t)**4)  # Moment of inertia of the cross section\n",
-      "sm1 = (M1*b)/(2*I)              # Comoressive stress due to M1 at A and B\n",
-      "Aweb = (2*t)*(b-(2*t))          # Area of the web\n",
-      "tp2 = P2/Aweb                   # Shear stress at point B by lpad P2\n",
-      "sm2 = (M2*b)/(2*I)              # Comoressive stress due to M2 at A \n",
-      "sa = sp1+sm1+sm2                # Total Compressive stress at point A\n",
-      "sb = sp1+sm1                    # Total compressive at point B \n",
-      "tb = tp2                        # Shear stress at point B\n",
-      "\n",
-      "# Principle stresses \n",
-      "sxa = 0\n",
-      "sya = -sa\n",
-      "txya = 0\n",
-      "sxb = 0\n",
-      "syb = -sb\n",
-      "txyb = tp2 \n",
-      "\n",
-      "# Stresses at A\n",
-      "s1a = (sxa+sya)/2 + math.sqrt(((sxa-sya)/2)**2 + (txya)**2)             # Maximum tensile stress \n",
-      "s2a = (sxa+sya)/2 - math.sqrt(((sxa-sya)/2)**2 + (txya)**2)             # Maximum compressive stress \n",
-      "tmaxa =  math.sqrt(((sxa-sya)/2)**2 + (txya)**2)                        # Maximum in plane shear stress\n",
-      "print \"Maximum tensile stress at point A is\", s1a,\"Psi\"\n",
-      "print \"Maximum compressive stress at point A is\", round(s2a,2), \"Psi\"\n",
-      "print \"Maximum in plane shear stress at point A is\", round(tmaxa,2), \"Psi\"\n",
-      "\n",
-      "# Stress at B \n",
-      "s1b = (sxb+syb)/2 + math.sqrt(((sxb-syb)/2)**2 + (txyb)**2)             # Maximum tensile stress \n",
-      "s2b = (sxb+syb)/2 - math.sqrt(((sxb-syb)/2)**2 + (txyb)**2)             # Maximum compressive stress \n",
-      "tmaxb =  math.sqrt(((sxb-syb)/2)**2 + (txyb)**2)                        # Maximum in plane shear stress\n",
-      "print \"Maximum tensile stress at point B is\", round(s1b,2), \"Psi\"\n",
-      "print \"Maximum compressive stress at point B is\", round(s2b,2), \"Psi\"\n",
-      "print \"Maximum in plane shear stress at point B is\", round(tmaxb,2), \"Psi\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum tensile stress at point A is 0.0 Psi\n",
-        "Maximum compressive stress at point A is -4090.91 Psi\n",
-        "Maximum in plane shear stress at point A is 2045.45 Psi\n",
-        "Maximum tensile stress at point B is 13.67 Psi\n",
-        "Maximum compressive stress at point B is -1872.69 Psi\n",
-        "Maximum in plane shear stress at point B is 943.18 Psi\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Testing_the_interface/screenshots/screen1.png b/Testing_the_interface/screenshots/screen1.png
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diff --git a/_Theory_Of_Machines_by__B._K._Sarkar/README.txt b/Theory_Of_Machines_by__B._K._Sarkar/README.txt
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index 1892548f..1892548f 100755
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diff --git a/_Theory_Of_Machines_by__B._K._Sarkar/screenshots/chapter3.png b/Theory_Of_Machines_by__B._K._Sarkar/screenshots/chapter3.png
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deleted file mode 100755
index cb655050..00000000
--- a/_Diffusion:_Mass_Transfer_In_Fluid_Systems_by__E._L._Cussler/screenshots/CH5.png
+++ /dev/null
diff --git a/_Engineering_Thermodynamics_by__O._Singh/screenshots/Screenshot_(49).png b/_Engineering_Thermodynamics_by__O._Singh/screenshots/Screenshot_(49).png
deleted file mode 100755
index 69b43e33..00000000
--- a/_Engineering_Thermodynamics_by__O._Singh/screenshots/Screenshot_(49).png
+++ /dev/null
diff --git a/_Engineering_Thermodynamics_by__O._Singh/screenshots/Screenshot_(50).png b/_Engineering_Thermodynamics_by__O._Singh/screenshots/Screenshot_(50).png
deleted file mode 100755
index b8c7aad6..00000000
--- a/_Engineering_Thermodynamics_by__O._Singh/screenshots/Screenshot_(50).png
+++ /dev/null
diff --git a/_Engineering_Thermodynamics_by__O._Singh/screenshots/Screenshot_(51).png b/_Engineering_Thermodynamics_by__O._Singh/screenshots/Screenshot_(51).png
deleted file mode 100755
index f3bb8ad5..00000000
--- a/_Engineering_Thermodynamics_by__O._Singh/screenshots/Screenshot_(51).png
+++ /dev/null
diff --git a/_Power_Electronics/Chapter10.ipynb b/_Power_Electronics/Chapter10.ipynb
deleted file mode 100755
index cbc3cb90..00000000
--- a/_Power_Electronics/Chapter10.ipynb
+++ /dev/null
@@ -1,228 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 10 : Cycloconverters"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 10.2, Page No 594"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "R=10.0\n",

-      "a=30.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_or=(V_m/math.sqrt(2))*math.sqrt((1/math.pi)*(math.pi-a*math.pi/180+math.sin(math.radians(2*a))/2))\n",

-      "I_or=V_or/R    \n",

-      "I_s=I_or\n",

-      "pf=(I_or**2*R)/(V_s*I_s)    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"rms value of o/p current=%.2f A\" %I_or)\n",

-      "print(\"rms value of o/p current for each convertor=%.2f A\" %(I_or/math.sqrt(2)))\n",

-      "print(\"rms value of o/p current for each thyristor=%.3f A\" %(I_or/2))\n",

-      "print(\"i/p pf=%.4f\" %pf)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rms value of o/p current=22.67 A\n",

-        "rms value of o/p current for each convertor=16.03 A\n",

-        "rms value of o/p current for each thyristor=11.333 A\n",

-        "i/p pf=0.9855\n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 10.4, Page No 604"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=400.0\n",

-      "V_ph=V_s/2\n",

-      "a=160.0\n",

-      "\n",

-      "#Calculations\n",

-      "r=math.cos(math.radians(180-a))\n",

-      "m=3\n",

-      "V_or=r*(V_ph*(m/math.pi)*math.sin(math.pi/m)) \n",

-      "R=2\n",

-      "X_L=1.5\n",

-      "th=math.degrees(math.atan(X_L/R))\n",

-      "Z=math.sqrt(R**2+X_L**2)\n",

-      "I_or=V_or/Z    \n",

-      "P=I_or**2*R      \n",

-      "\n",

-      "#Results\n",

-      "print(\"rms o/p voltage=%.3f V\" %V_or)\n",

-      "print(\"rms o/p current=%.2f A\" %I_or)\n",

-      "print(\"phase angle of o/p current=%.2f deg\" %-th)\n",

-      "print(\"o/p power=%.2f W\" %P)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rms o/p voltage=155.424 V\n",

-        "rms o/p current=62.17 A\n",

-        "phase angle of o/p current=-36.87 deg\n",

-        "o/p power=7730.11 W\n"

-       ]

-      }

-     ],

-     "prompt_number": 2

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 10.5 Page No 604"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=400.0\n",

-      "V_ph=V_s/2\n",

-      "V_l=V_ph*math.sqrt(3)\n",

-      "a=160.0\n",

-      "\n",

-      "#Calculations\n",

-      "r=math.cos(math.radians(180-a))\n",

-      "m=6\n",

-      "V_or=r*(V_l*(m/math.pi)*math.sin(math.pi/m))    \n",

-      "R=2\n",

-      "X_L=1.5\n",

-      "th=math.degrees(math.atan(X_L/R))\n",

-      "Z=math.sqrt(R**2+X_L**2)\n",

-      "I_or=V_or/Z    \n",

-      "P=I_or**2*R    \n",

-      "\n",

-      "#Results\n",

-      "print(\"rms o/p voltage=%.2f V\" %V_or)\n",

-      "print(\"rms o/p current=%.2f A\" %I_or)\n",

-      "print(\"phase angle of o/p current=%.2f deg\" %-th)\n",

-      "print(\"o/p power=%.2f W\" %P)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rms o/p voltage=310.85 V\n",

-        "rms o/p current=124.34 A\n",

-        "phase angle of o/p current=-36.87 deg\n",

-        "o/p power=30920.44 W\n"

-       ]

-      }

-     ],

-     "prompt_number": 3

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 10.7, Page No 605"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_l=400.0\n",

-      "V_ml=math.sqrt(2)*V_l\n",

-      "m=6\n",

-      "f=50.0\n",

-      "w=2*math.pi*f\n",

-      "L=.0012\n",

-      "I=40.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_or1=(V_ml*(m/math.pi)*math.sin(math.pi/m))*math.cos(math.radians(a))\n",

-      "V_omx1=V_or1-3*w*L*I/math.pi\n",

-      "V_rms1=V_omx1/math.sqrt(2)    \n",

-      "a2=30.0\n",

-      "V_or2=(V_ml*(m/math.pi)*math.sin(math.pi/m))*math.cos(math.radians(a))\n",

-      "V_omx2=V_or2-3*w*L*I/math.pi\n",

-      "V_rms2=V_omx2/math.sqrt(2)    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"for firing angle=0deg\")\n",

-      "a1=0\n",

-      "print(\"rms value of load voltage=%.2f V\" %V_rms2)\n",

-      "print(\"for firing angle=30deg\")\n",

-      "print(\"rms value of load voltage=%.2f V\" %V_rms2)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for firing angle=0deg\n",

-        "rms value of load voltage=-369.12 V\n",

-        "for firing angle=30deg\n",

-        "rms value of load voltage=-369.12 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 4

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Power_Electronics/Chapter10_1.ipynb b/_Power_Electronics/Chapter10_1.ipynb
deleted file mode 100755
index cbc3cb90..00000000
--- a/_Power_Electronics/Chapter10_1.ipynb
+++ /dev/null
@@ -1,228 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 10 : Cycloconverters"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 10.2, Page No 594"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "R=10.0\n",

-      "a=30.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_or=(V_m/math.sqrt(2))*math.sqrt((1/math.pi)*(math.pi-a*math.pi/180+math.sin(math.radians(2*a))/2))\n",

-      "I_or=V_or/R    \n",

-      "I_s=I_or\n",

-      "pf=(I_or**2*R)/(V_s*I_s)    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"rms value of o/p current=%.2f A\" %I_or)\n",

-      "print(\"rms value of o/p current for each convertor=%.2f A\" %(I_or/math.sqrt(2)))\n",

-      "print(\"rms value of o/p current for each thyristor=%.3f A\" %(I_or/2))\n",

-      "print(\"i/p pf=%.4f\" %pf)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rms value of o/p current=22.67 A\n",

-        "rms value of o/p current for each convertor=16.03 A\n",

-        "rms value of o/p current for each thyristor=11.333 A\n",

-        "i/p pf=0.9855\n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 10.4, Page No 604"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=400.0\n",

-      "V_ph=V_s/2\n",

-      "a=160.0\n",

-      "\n",

-      "#Calculations\n",

-      "r=math.cos(math.radians(180-a))\n",

-      "m=3\n",

-      "V_or=r*(V_ph*(m/math.pi)*math.sin(math.pi/m)) \n",

-      "R=2\n",

-      "X_L=1.5\n",

-      "th=math.degrees(math.atan(X_L/R))\n",

-      "Z=math.sqrt(R**2+X_L**2)\n",

-      "I_or=V_or/Z    \n",

-      "P=I_or**2*R      \n",

-      "\n",

-      "#Results\n",

-      "print(\"rms o/p voltage=%.3f V\" %V_or)\n",

-      "print(\"rms o/p current=%.2f A\" %I_or)\n",

-      "print(\"phase angle of o/p current=%.2f deg\" %-th)\n",

-      "print(\"o/p power=%.2f W\" %P)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rms o/p voltage=155.424 V\n",

-        "rms o/p current=62.17 A\n",

-        "phase angle of o/p current=-36.87 deg\n",

-        "o/p power=7730.11 W\n"

-       ]

-      }

-     ],

-     "prompt_number": 2

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 10.5 Page No 604"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=400.0\n",

-      "V_ph=V_s/2\n",

-      "V_l=V_ph*math.sqrt(3)\n",

-      "a=160.0\n",

-      "\n",

-      "#Calculations\n",

-      "r=math.cos(math.radians(180-a))\n",

-      "m=6\n",

-      "V_or=r*(V_l*(m/math.pi)*math.sin(math.pi/m))    \n",

-      "R=2\n",

-      "X_L=1.5\n",

-      "th=math.degrees(math.atan(X_L/R))\n",

-      "Z=math.sqrt(R**2+X_L**2)\n",

-      "I_or=V_or/Z    \n",

-      "P=I_or**2*R    \n",

-      "\n",

-      "#Results\n",

-      "print(\"rms o/p voltage=%.2f V\" %V_or)\n",

-      "print(\"rms o/p current=%.2f A\" %I_or)\n",

-      "print(\"phase angle of o/p current=%.2f deg\" %-th)\n",

-      "print(\"o/p power=%.2f W\" %P)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rms o/p voltage=310.85 V\n",

-        "rms o/p current=124.34 A\n",

-        "phase angle of o/p current=-36.87 deg\n",

-        "o/p power=30920.44 W\n"

-       ]

-      }

-     ],

-     "prompt_number": 3

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 10.7, Page No 605"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_l=400.0\n",

-      "V_ml=math.sqrt(2)*V_l\n",

-      "m=6\n",

-      "f=50.0\n",

-      "w=2*math.pi*f\n",

-      "L=.0012\n",

-      "I=40.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_or1=(V_ml*(m/math.pi)*math.sin(math.pi/m))*math.cos(math.radians(a))\n",

-      "V_omx1=V_or1-3*w*L*I/math.pi\n",

-      "V_rms1=V_omx1/math.sqrt(2)    \n",

-      "a2=30.0\n",

-      "V_or2=(V_ml*(m/math.pi)*math.sin(math.pi/m))*math.cos(math.radians(a))\n",

-      "V_omx2=V_or2-3*w*L*I/math.pi\n",

-      "V_rms2=V_omx2/math.sqrt(2)    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"for firing angle=0deg\")\n",

-      "a1=0\n",

-      "print(\"rms value of load voltage=%.2f V\" %V_rms2)\n",

-      "print(\"for firing angle=30deg\")\n",

-      "print(\"rms value of load voltage=%.2f V\" %V_rms2)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for firing angle=0deg\n",

-        "rms value of load voltage=-369.12 V\n",

-        "for firing angle=30deg\n",

-        "rms value of load voltage=-369.12 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 4

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Power_Electronics/Chapter10_2.ipynb b/_Power_Electronics/Chapter10_2.ipynb
deleted file mode 100755
index cbc3cb90..00000000
--- a/_Power_Electronics/Chapter10_2.ipynb
+++ /dev/null
@@ -1,228 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 10 : Cycloconverters"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 10.2, Page No 594"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "R=10.0\n",

-      "a=30.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_or=(V_m/math.sqrt(2))*math.sqrt((1/math.pi)*(math.pi-a*math.pi/180+math.sin(math.radians(2*a))/2))\n",

-      "I_or=V_or/R    \n",

-      "I_s=I_or\n",

-      "pf=(I_or**2*R)/(V_s*I_s)    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"rms value of o/p current=%.2f A\" %I_or)\n",

-      "print(\"rms value of o/p current for each convertor=%.2f A\" %(I_or/math.sqrt(2)))\n",

-      "print(\"rms value of o/p current for each thyristor=%.3f A\" %(I_or/2))\n",

-      "print(\"i/p pf=%.4f\" %pf)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rms value of o/p current=22.67 A\n",

-        "rms value of o/p current for each convertor=16.03 A\n",

-        "rms value of o/p current for each thyristor=11.333 A\n",

-        "i/p pf=0.9855\n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 10.4, Page No 604"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=400.0\n",

-      "V_ph=V_s/2\n",

-      "a=160.0\n",

-      "\n",

-      "#Calculations\n",

-      "r=math.cos(math.radians(180-a))\n",

-      "m=3\n",

-      "V_or=r*(V_ph*(m/math.pi)*math.sin(math.pi/m)) \n",

-      "R=2\n",

-      "X_L=1.5\n",

-      "th=math.degrees(math.atan(X_L/R))\n",

-      "Z=math.sqrt(R**2+X_L**2)\n",

-      "I_or=V_or/Z    \n",

-      "P=I_or**2*R      \n",

-      "\n",

-      "#Results\n",

-      "print(\"rms o/p voltage=%.3f V\" %V_or)\n",

-      "print(\"rms o/p current=%.2f A\" %I_or)\n",

-      "print(\"phase angle of o/p current=%.2f deg\" %-th)\n",

-      "print(\"o/p power=%.2f W\" %P)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rms o/p voltage=155.424 V\n",

-        "rms o/p current=62.17 A\n",

-        "phase angle of o/p current=-36.87 deg\n",

-        "o/p power=7730.11 W\n"

-       ]

-      }

-     ],

-     "prompt_number": 2

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 10.5 Page No 604"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=400.0\n",

-      "V_ph=V_s/2\n",

-      "V_l=V_ph*math.sqrt(3)\n",

-      "a=160.0\n",

-      "\n",

-      "#Calculations\n",

-      "r=math.cos(math.radians(180-a))\n",

-      "m=6\n",

-      "V_or=r*(V_l*(m/math.pi)*math.sin(math.pi/m))    \n",

-      "R=2\n",

-      "X_L=1.5\n",

-      "th=math.degrees(math.atan(X_L/R))\n",

-      "Z=math.sqrt(R**2+X_L**2)\n",

-      "I_or=V_or/Z    \n",

-      "P=I_or**2*R    \n",

-      "\n",

-      "#Results\n",

-      "print(\"rms o/p voltage=%.2f V\" %V_or)\n",

-      "print(\"rms o/p current=%.2f A\" %I_or)\n",

-      "print(\"phase angle of o/p current=%.2f deg\" %-th)\n",

-      "print(\"o/p power=%.2f W\" %P)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rms o/p voltage=310.85 V\n",

-        "rms o/p current=124.34 A\n",

-        "phase angle of o/p current=-36.87 deg\n",

-        "o/p power=30920.44 W\n"

-       ]

-      }

-     ],

-     "prompt_number": 3

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 10.7, Page No 605"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_l=400.0\n",

-      "V_ml=math.sqrt(2)*V_l\n",

-      "m=6\n",

-      "f=50.0\n",

-      "w=2*math.pi*f\n",

-      "L=.0012\n",

-      "I=40.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_or1=(V_ml*(m/math.pi)*math.sin(math.pi/m))*math.cos(math.radians(a))\n",

-      "V_omx1=V_or1-3*w*L*I/math.pi\n",

-      "V_rms1=V_omx1/math.sqrt(2)    \n",

-      "a2=30.0\n",

-      "V_or2=(V_ml*(m/math.pi)*math.sin(math.pi/m))*math.cos(math.radians(a))\n",

-      "V_omx2=V_or2-3*w*L*I/math.pi\n",

-      "V_rms2=V_omx2/math.sqrt(2)    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"for firing angle=0deg\")\n",

-      "a1=0\n",

-      "print(\"rms value of load voltage=%.2f V\" %V_rms2)\n",

-      "print(\"for firing angle=30deg\")\n",

-      "print(\"rms value of load voltage=%.2f V\" %V_rms2)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for firing angle=0deg\n",

-        "rms value of load voltage=-369.12 V\n",

-        "for firing angle=30deg\n",

-        "rms value of load voltage=-369.12 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 4

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Power_Electronics/Chapter10_3.ipynb b/_Power_Electronics/Chapter10_3.ipynb
deleted file mode 100755
index cbc3cb90..00000000
--- a/_Power_Electronics/Chapter10_3.ipynb
+++ /dev/null
@@ -1,228 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 10 : Cycloconverters"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 10.2, Page No 594"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "R=10.0\n",

-      "a=30.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_or=(V_m/math.sqrt(2))*math.sqrt((1/math.pi)*(math.pi-a*math.pi/180+math.sin(math.radians(2*a))/2))\n",

-      "I_or=V_or/R    \n",

-      "I_s=I_or\n",

-      "pf=(I_or**2*R)/(V_s*I_s)    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"rms value of o/p current=%.2f A\" %I_or)\n",

-      "print(\"rms value of o/p current for each convertor=%.2f A\" %(I_or/math.sqrt(2)))\n",

-      "print(\"rms value of o/p current for each thyristor=%.3f A\" %(I_or/2))\n",

-      "print(\"i/p pf=%.4f\" %pf)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rms value of o/p current=22.67 A\n",

-        "rms value of o/p current for each convertor=16.03 A\n",

-        "rms value of o/p current for each thyristor=11.333 A\n",

-        "i/p pf=0.9855\n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 10.4, Page No 604"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=400.0\n",

-      "V_ph=V_s/2\n",

-      "a=160.0\n",

-      "\n",

-      "#Calculations\n",

-      "r=math.cos(math.radians(180-a))\n",

-      "m=3\n",

-      "V_or=r*(V_ph*(m/math.pi)*math.sin(math.pi/m)) \n",

-      "R=2\n",

-      "X_L=1.5\n",

-      "th=math.degrees(math.atan(X_L/R))\n",

-      "Z=math.sqrt(R**2+X_L**2)\n",

-      "I_or=V_or/Z    \n",

-      "P=I_or**2*R      \n",

-      "\n",

-      "#Results\n",

-      "print(\"rms o/p voltage=%.3f V\" %V_or)\n",

-      "print(\"rms o/p current=%.2f A\" %I_or)\n",

-      "print(\"phase angle of o/p current=%.2f deg\" %-th)\n",

-      "print(\"o/p power=%.2f W\" %P)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rms o/p voltage=155.424 V\n",

-        "rms o/p current=62.17 A\n",

-        "phase angle of o/p current=-36.87 deg\n",

-        "o/p power=7730.11 W\n"

-       ]

-      }

-     ],

-     "prompt_number": 2

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 10.5 Page No 604"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=400.0\n",

-      "V_ph=V_s/2\n",

-      "V_l=V_ph*math.sqrt(3)\n",

-      "a=160.0\n",

-      "\n",

-      "#Calculations\n",

-      "r=math.cos(math.radians(180-a))\n",

-      "m=6\n",

-      "V_or=r*(V_l*(m/math.pi)*math.sin(math.pi/m))    \n",

-      "R=2\n",

-      "X_L=1.5\n",

-      "th=math.degrees(math.atan(X_L/R))\n",

-      "Z=math.sqrt(R**2+X_L**2)\n",

-      "I_or=V_or/Z    \n",

-      "P=I_or**2*R    \n",

-      "\n",

-      "#Results\n",

-      "print(\"rms o/p voltage=%.2f V\" %V_or)\n",

-      "print(\"rms o/p current=%.2f A\" %I_or)\n",

-      "print(\"phase angle of o/p current=%.2f deg\" %-th)\n",

-      "print(\"o/p power=%.2f W\" %P)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rms o/p voltage=310.85 V\n",

-        "rms o/p current=124.34 A\n",

-        "phase angle of o/p current=-36.87 deg\n",

-        "o/p power=30920.44 W\n"

-       ]

-      }

-     ],

-     "prompt_number": 3

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 10.7, Page No 605"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_l=400.0\n",

-      "V_ml=math.sqrt(2)*V_l\n",

-      "m=6\n",

-      "f=50.0\n",

-      "w=2*math.pi*f\n",

-      "L=.0012\n",

-      "I=40.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_or1=(V_ml*(m/math.pi)*math.sin(math.pi/m))*math.cos(math.radians(a))\n",

-      "V_omx1=V_or1-3*w*L*I/math.pi\n",

-      "V_rms1=V_omx1/math.sqrt(2)    \n",

-      "a2=30.0\n",

-      "V_or2=(V_ml*(m/math.pi)*math.sin(math.pi/m))*math.cos(math.radians(a))\n",

-      "V_omx2=V_or2-3*w*L*I/math.pi\n",

-      "V_rms2=V_omx2/math.sqrt(2)    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"for firing angle=0deg\")\n",

-      "a1=0\n",

-      "print(\"rms value of load voltage=%.2f V\" %V_rms2)\n",

-      "print(\"for firing angle=30deg\")\n",

-      "print(\"rms value of load voltage=%.2f V\" %V_rms2)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for firing angle=0deg\n",

-        "rms value of load voltage=-369.12 V\n",

-        "for firing angle=30deg\n",

-        "rms value of load voltage=-369.12 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 4

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Power_Electronics/Chapter10_4.ipynb b/_Power_Electronics/Chapter10_4.ipynb
deleted file mode 100755
index cbc3cb90..00000000
--- a/_Power_Electronics/Chapter10_4.ipynb
+++ /dev/null
@@ -1,228 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 10 : Cycloconverters"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 10.2, Page No 594"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "R=10.0\n",

-      "a=30.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_or=(V_m/math.sqrt(2))*math.sqrt((1/math.pi)*(math.pi-a*math.pi/180+math.sin(math.radians(2*a))/2))\n",

-      "I_or=V_or/R    \n",

-      "I_s=I_or\n",

-      "pf=(I_or**2*R)/(V_s*I_s)    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"rms value of o/p current=%.2f A\" %I_or)\n",

-      "print(\"rms value of o/p current for each convertor=%.2f A\" %(I_or/math.sqrt(2)))\n",

-      "print(\"rms value of o/p current for each thyristor=%.3f A\" %(I_or/2))\n",

-      "print(\"i/p pf=%.4f\" %pf)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rms value of o/p current=22.67 A\n",

-        "rms value of o/p current for each convertor=16.03 A\n",

-        "rms value of o/p current for each thyristor=11.333 A\n",

-        "i/p pf=0.9855\n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 10.4, Page No 604"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=400.0\n",

-      "V_ph=V_s/2\n",

-      "a=160.0\n",

-      "\n",

-      "#Calculations\n",

-      "r=math.cos(math.radians(180-a))\n",

-      "m=3\n",

-      "V_or=r*(V_ph*(m/math.pi)*math.sin(math.pi/m)) \n",

-      "R=2\n",

-      "X_L=1.5\n",

-      "th=math.degrees(math.atan(X_L/R))\n",

-      "Z=math.sqrt(R**2+X_L**2)\n",

-      "I_or=V_or/Z    \n",

-      "P=I_or**2*R      \n",

-      "\n",

-      "#Results\n",

-      "print(\"rms o/p voltage=%.3f V\" %V_or)\n",

-      "print(\"rms o/p current=%.2f A\" %I_or)\n",

-      "print(\"phase angle of o/p current=%.2f deg\" %-th)\n",

-      "print(\"o/p power=%.2f W\" %P)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rms o/p voltage=155.424 V\n",

-        "rms o/p current=62.17 A\n",

-        "phase angle of o/p current=-36.87 deg\n",

-        "o/p power=7730.11 W\n"

-       ]

-      }

-     ],

-     "prompt_number": 2

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 10.5 Page No 604"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=400.0\n",

-      "V_ph=V_s/2\n",

-      "V_l=V_ph*math.sqrt(3)\n",

-      "a=160.0\n",

-      "\n",

-      "#Calculations\n",

-      "r=math.cos(math.radians(180-a))\n",

-      "m=6\n",

-      "V_or=r*(V_l*(m/math.pi)*math.sin(math.pi/m))    \n",

-      "R=2\n",

-      "X_L=1.5\n",

-      "th=math.degrees(math.atan(X_L/R))\n",

-      "Z=math.sqrt(R**2+X_L**2)\n",

-      "I_or=V_or/Z    \n",

-      "P=I_or**2*R    \n",

-      "\n",

-      "#Results\n",

-      "print(\"rms o/p voltage=%.2f V\" %V_or)\n",

-      "print(\"rms o/p current=%.2f A\" %I_or)\n",

-      "print(\"phase angle of o/p current=%.2f deg\" %-th)\n",

-      "print(\"o/p power=%.2f W\" %P)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rms o/p voltage=310.85 V\n",

-        "rms o/p current=124.34 A\n",

-        "phase angle of o/p current=-36.87 deg\n",

-        "o/p power=30920.44 W\n"

-       ]

-      }

-     ],

-     "prompt_number": 3

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 10.7, Page No 605"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_l=400.0\n",

-      "V_ml=math.sqrt(2)*V_l\n",

-      "m=6\n",

-      "f=50.0\n",

-      "w=2*math.pi*f\n",

-      "L=.0012\n",

-      "I=40.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_or1=(V_ml*(m/math.pi)*math.sin(math.pi/m))*math.cos(math.radians(a))\n",

-      "V_omx1=V_or1-3*w*L*I/math.pi\n",

-      "V_rms1=V_omx1/math.sqrt(2)    \n",

-      "a2=30.0\n",

-      "V_or2=(V_ml*(m/math.pi)*math.sin(math.pi/m))*math.cos(math.radians(a))\n",

-      "V_omx2=V_or2-3*w*L*I/math.pi\n",

-      "V_rms2=V_omx2/math.sqrt(2)    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"for firing angle=0deg\")\n",

-      "a1=0\n",

-      "print(\"rms value of load voltage=%.2f V\" %V_rms2)\n",

-      "print(\"for firing angle=30deg\")\n",

-      "print(\"rms value of load voltage=%.2f V\" %V_rms2)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for firing angle=0deg\n",

-        "rms value of load voltage=-369.12 V\n",

-        "for firing angle=30deg\n",

-        "rms value of load voltage=-369.12 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 4

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Power_Electronics/Chapter11.ipynb b/_Power_Electronics/Chapter11.ipynb
deleted file mode 100755
index d2317d28..00000000
--- a/_Power_Electronics/Chapter11.ipynb
+++ /dev/null
@@ -1,299 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 11 : Some Applications"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 11.1, Page No 622"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=11000.0\n",

-      "V_ml=math.sqrt(2)*V_s\n",

-      "f=50.0\n",

-      "\n",

-      "#Calculations\n",

-      "w=2*math.pi*f\n",

-      "I_d=300\n",

-      "R_d=1\n",

-      "g=20 #g=gamma\n",

-      "a=math.degrees(math.acos(math.cos(math.radians(g))+math.pi/(3*V_ml)*I_d*R_d))    \n",

-      "L_s=.01\n",

-      "V_d=(3/math.pi)*((V_ml*math.cos(math.radians(a)))-w*L_s*I_d)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"firing angle=%.3f deg\" %a)\n",

-      "print(\"rectifier o/p voltage=%.1f V\" %V_d)\n",

-      "print(\"dc link voltage=%.3f V\" %(2*V_d/1000))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "firing angle=16.283 deg\n",

-        "rectifier o/p voltage=13359.3 V\n",

-        "dc link voltage=26.719 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 11.2, Page No 623"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_d=(200.0+200)*10**3\n",

-      "P=1000.0*10**6\n",

-      "\n",

-      "#Calculations\n",

-      "I_d=P/V_d\n",

-      " #each thristor conducts for 120deg for a periodicity of 360deg\n",

-      "a=0\n",

-      "V_d=200.0*10**3\n",

-      "V_ml=V_d*math.pi/(3*math.cos(math.radians(a)))\n",

-      "\n",

-      "#Results\n",

-      "print(\"rms current rating of thyristor=%.2f A\" %(I_d*math.sqrt(120/360)))\n",

-      "print(\"peak reverse voltage across each thyristor=%.2f kV\" %(V_ml/2/1000))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rms current rating of thyristor=0.00 A\n",

-        "peak reverse voltage across each thyristor=104.72 kV\n"

-       ]

-      }

-     ],

-     "prompt_number": 2

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 11.3 Page No 627"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_m=230.0\n",

-      "V_s=230/math.sqrt(2)\n",

-      "pf=0.8\n",

-      "P=2000.0\n",

-      "\n",

-      "#Calculations\n",

-      "I_m=P/(V_s*pf)\n",

-      "I_Tr=I_m/math.sqrt(2)\n",

-      "I_TA=2*I_m/math.pi\n",

-      "fos=2 #factor of safety\n",

-      "PIV=V_m*math.sqrt(2)\n",

-      "I_Tr=I_m/(2)\n",

-      "I_TA=I_m/math.pi\n",

-      "\n",

-      "#Results\n",

-      "print(\"rms value of thyristor current=%.2f A\" %(fos*I_Tr))\n",

-      "print(\"avg value of thyristor current=%.3f A\" %(fos*I_TA))\n",

-      "print(\"voltage rating of thyristor=%.2f V\" %PIV)\n",

-      "print(\"rms value of diode current=%.3f A\" %(fos*I_Tr))\n",

-      "print(\"avg value of diode current=%.3f A\" %(fos*I_TA))\n",

-      "print(\"voltage rating of diode=%.2f V\" %PIV)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rms value of thyristor current=15.37 A\n",

-        "avg value of thyristor current=9.786 A\n",

-        "voltage rating of thyristor=325.27 V\n",

-        "rms value of diode current=15.372 A\n",

-        "avg value of diode current=9.786 A\n",

-        "voltage rating of diode=325.27 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 3

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 11.4, Page No 629"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=200.0\n",

-      "I=10.0\n",

-      "\n",

-      "#Calculations\n",

-      "R_L=V/I    \n",

-      "I_h=.005     #holding current\n",

-      "R2=V/I_h    \n",

-      "t_c=20*10**-6\n",

-      "fos=2 #factor of safety\n",

-      "C=t_c*fos/(R_L*math.log(2))    \n",

-      "\n",

-      "#Results\n",

-      "print(\"value of load resistance=%.0f ohm\" %R_L)\n",

-      "print(\"value of R2=%.0f kilo-ohm\" %(R2/1000))\n",

-      "print(\"value of C=%.3f uF\" %(C*10**6))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "value of load resistance=20 ohm\n",

-        "value of R2=40 kilo-ohm\n",

-        "value of C=2.885 uF\n"

-       ]

-      }

-     ],

-     "prompt_number": 4

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 11.5 Page No 646"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "u_r=10\n",

-      "f=10000.0 #Hz\n",

-      "p=4.0*10**-8 #ohm-m\n",

-      "\n",

-      "#Calculations\n",

-      "dl=(1/(2*math.pi))*math.sqrt(p*10**7/(u_r*f))    \n",

-      "l=0.12 #length of cylinder\n",

-      "t=20.0 #no of turns\n",

-      "I=100.0\n",

-      "H=t*I/l\n",

-      "P_s=2*math.pi*H**2*math.sqrt(u_r*f*p*10**-7)    \n",

-      "d=.02 #diameter\n",

-      "P_v=4*H**2*p/(d*dl)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"depth of heat of penetration=%.5f mm\" %(dl*1000))\n",

-      "print(\"heat generated per unit cylinder surface area=%.3f W/m**2\" %P_s)\n",

-      "print(\"heat generated per unit cylinder volume=%.0f W/m**3\" %P_v)\n",

-      " #answer of P_v varies as given in book as value of d is not taken as in formulae. "

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "depth of heat of penetration=0.31831 mm\n",

-        "heat generated per unit cylinder surface area=34906.585 W/m**2\n",

-        "heat generated per unit cylinder volume=6981317 W/m**3\n"

-       ]

-      }

-     ],

-     "prompt_number": 5

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 11.6 Page No 646"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "f=3000.0\n",

-      "\n",

-      "#Calculations\n",

-      "t_qmin=30.0*10**-6\n",

-      "f_r=f/(1-2*t_qmin*f)\n",

-      "R=0.06\n",

-      "L=20.0*10**-6\n",

-      "C=1/(L*((2*math.pi*f_r)**2+(R/(2*L))**2))    \n",

-      "\n",

-      "#Results\n",

-      "print(\"required capacitor size=%.4f F\" %(C*10**6))\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "required capacitor size=94.2215 F\n"

-       ]

-      }

-     ],

-     "prompt_number": 6

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Power_Electronics/Chapter11_1.ipynb b/_Power_Electronics/Chapter11_1.ipynb
deleted file mode 100755
index d2317d28..00000000
--- a/_Power_Electronics/Chapter11_1.ipynb
+++ /dev/null
@@ -1,299 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 11 : Some Applications"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 11.1, Page No 622"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=11000.0\n",

-      "V_ml=math.sqrt(2)*V_s\n",

-      "f=50.0\n",

-      "\n",

-      "#Calculations\n",

-      "w=2*math.pi*f\n",

-      "I_d=300\n",

-      "R_d=1\n",

-      "g=20 #g=gamma\n",

-      "a=math.degrees(math.acos(math.cos(math.radians(g))+math.pi/(3*V_ml)*I_d*R_d))    \n",

-      "L_s=.01\n",

-      "V_d=(3/math.pi)*((V_ml*math.cos(math.radians(a)))-w*L_s*I_d)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"firing angle=%.3f deg\" %a)\n",

-      "print(\"rectifier o/p voltage=%.1f V\" %V_d)\n",

-      "print(\"dc link voltage=%.3f V\" %(2*V_d/1000))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "firing angle=16.283 deg\n",

-        "rectifier o/p voltage=13359.3 V\n",

-        "dc link voltage=26.719 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 11.2, Page No 623"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_d=(200.0+200)*10**3\n",

-      "P=1000.0*10**6\n",

-      "\n",

-      "#Calculations\n",

-      "I_d=P/V_d\n",

-      " #each thristor conducts for 120deg for a periodicity of 360deg\n",

-      "a=0\n",

-      "V_d=200.0*10**3\n",

-      "V_ml=V_d*math.pi/(3*math.cos(math.radians(a)))\n",

-      "\n",

-      "#Results\n",

-      "print(\"rms current rating of thyristor=%.2f A\" %(I_d*math.sqrt(120/360)))\n",

-      "print(\"peak reverse voltage across each thyristor=%.2f kV\" %(V_ml/2/1000))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rms current rating of thyristor=0.00 A\n",

-        "peak reverse voltage across each thyristor=104.72 kV\n"

-       ]

-      }

-     ],

-     "prompt_number": 2

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 11.3 Page No 627"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_m=230.0\n",

-      "V_s=230/math.sqrt(2)\n",

-      "pf=0.8\n",

-      "P=2000.0\n",

-      "\n",

-      "#Calculations\n",

-      "I_m=P/(V_s*pf)\n",

-      "I_Tr=I_m/math.sqrt(2)\n",

-      "I_TA=2*I_m/math.pi\n",

-      "fos=2 #factor of safety\n",

-      "PIV=V_m*math.sqrt(2)\n",

-      "I_Tr=I_m/(2)\n",

-      "I_TA=I_m/math.pi\n",

-      "\n",

-      "#Results\n",

-      "print(\"rms value of thyristor current=%.2f A\" %(fos*I_Tr))\n",

-      "print(\"avg value of thyristor current=%.3f A\" %(fos*I_TA))\n",

-      "print(\"voltage rating of thyristor=%.2f V\" %PIV)\n",

-      "print(\"rms value of diode current=%.3f A\" %(fos*I_Tr))\n",

-      "print(\"avg value of diode current=%.3f A\" %(fos*I_TA))\n",

-      "print(\"voltage rating of diode=%.2f V\" %PIV)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rms value of thyristor current=15.37 A\n",

-        "avg value of thyristor current=9.786 A\n",

-        "voltage rating of thyristor=325.27 V\n",

-        "rms value of diode current=15.372 A\n",

-        "avg value of diode current=9.786 A\n",

-        "voltage rating of diode=325.27 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 3

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 11.4, Page No 629"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=200.0\n",

-      "I=10.0\n",

-      "\n",

-      "#Calculations\n",

-      "R_L=V/I    \n",

-      "I_h=.005     #holding current\n",

-      "R2=V/I_h    \n",

-      "t_c=20*10**-6\n",

-      "fos=2 #factor of safety\n",

-      "C=t_c*fos/(R_L*math.log(2))    \n",

-      "\n",

-      "#Results\n",

-      "print(\"value of load resistance=%.0f ohm\" %R_L)\n",

-      "print(\"value of R2=%.0f kilo-ohm\" %(R2/1000))\n",

-      "print(\"value of C=%.3f uF\" %(C*10**6))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "value of load resistance=20 ohm\n",

-        "value of R2=40 kilo-ohm\n",

-        "value of C=2.885 uF\n"

-       ]

-      }

-     ],

-     "prompt_number": 4

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 11.5 Page No 646"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "u_r=10\n",

-      "f=10000.0 #Hz\n",

-      "p=4.0*10**-8 #ohm-m\n",

-      "\n",

-      "#Calculations\n",

-      "dl=(1/(2*math.pi))*math.sqrt(p*10**7/(u_r*f))    \n",

-      "l=0.12 #length of cylinder\n",

-      "t=20.0 #no of turns\n",

-      "I=100.0\n",

-      "H=t*I/l\n",

-      "P_s=2*math.pi*H**2*math.sqrt(u_r*f*p*10**-7)    \n",

-      "d=.02 #diameter\n",

-      "P_v=4*H**2*p/(d*dl)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"depth of heat of penetration=%.5f mm\" %(dl*1000))\n",

-      "print(\"heat generated per unit cylinder surface area=%.3f W/m**2\" %P_s)\n",

-      "print(\"heat generated per unit cylinder volume=%.0f W/m**3\" %P_v)\n",

-      " #answer of P_v varies as given in book as value of d is not taken as in formulae. "

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "depth of heat of penetration=0.31831 mm\n",

-        "heat generated per unit cylinder surface area=34906.585 W/m**2\n",

-        "heat generated per unit cylinder volume=6981317 W/m**3\n"

-       ]

-      }

-     ],

-     "prompt_number": 5

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 11.6 Page No 646"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "f=3000.0\n",

-      "\n",

-      "#Calculations\n",

-      "t_qmin=30.0*10**-6\n",

-      "f_r=f/(1-2*t_qmin*f)\n",

-      "R=0.06\n",

-      "L=20.0*10**-6\n",

-      "C=1/(L*((2*math.pi*f_r)**2+(R/(2*L))**2))    \n",

-      "\n",

-      "#Results\n",

-      "print(\"required capacitor size=%.4f F\" %(C*10**6))\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "required capacitor size=94.2215 F\n"

-       ]

-      }

-     ],

-     "prompt_number": 6

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Power_Electronics/Chapter11_2.ipynb b/_Power_Electronics/Chapter11_2.ipynb
deleted file mode 100755
index d2317d28..00000000
--- a/_Power_Electronics/Chapter11_2.ipynb
+++ /dev/null
@@ -1,299 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 11 : Some Applications"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 11.1, Page No 622"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=11000.0\n",

-      "V_ml=math.sqrt(2)*V_s\n",

-      "f=50.0\n",

-      "\n",

-      "#Calculations\n",

-      "w=2*math.pi*f\n",

-      "I_d=300\n",

-      "R_d=1\n",

-      "g=20 #g=gamma\n",

-      "a=math.degrees(math.acos(math.cos(math.radians(g))+math.pi/(3*V_ml)*I_d*R_d))    \n",

-      "L_s=.01\n",

-      "V_d=(3/math.pi)*((V_ml*math.cos(math.radians(a)))-w*L_s*I_d)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"firing angle=%.3f deg\" %a)\n",

-      "print(\"rectifier o/p voltage=%.1f V\" %V_d)\n",

-      "print(\"dc link voltage=%.3f V\" %(2*V_d/1000))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "firing angle=16.283 deg\n",

-        "rectifier o/p voltage=13359.3 V\n",

-        "dc link voltage=26.719 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 11.2, Page No 623"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_d=(200.0+200)*10**3\n",

-      "P=1000.0*10**6\n",

-      "\n",

-      "#Calculations\n",

-      "I_d=P/V_d\n",

-      " #each thristor conducts for 120deg for a periodicity of 360deg\n",

-      "a=0\n",

-      "V_d=200.0*10**3\n",

-      "V_ml=V_d*math.pi/(3*math.cos(math.radians(a)))\n",

-      "\n",

-      "#Results\n",

-      "print(\"rms current rating of thyristor=%.2f A\" %(I_d*math.sqrt(120/360)))\n",

-      "print(\"peak reverse voltage across each thyristor=%.2f kV\" %(V_ml/2/1000))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rms current rating of thyristor=0.00 A\n",

-        "peak reverse voltage across each thyristor=104.72 kV\n"

-       ]

-      }

-     ],

-     "prompt_number": 2

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 11.3 Page No 627"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_m=230.0\n",

-      "V_s=230/math.sqrt(2)\n",

-      "pf=0.8\n",

-      "P=2000.0\n",

-      "\n",

-      "#Calculations\n",

-      "I_m=P/(V_s*pf)\n",

-      "I_Tr=I_m/math.sqrt(2)\n",

-      "I_TA=2*I_m/math.pi\n",

-      "fos=2 #factor of safety\n",

-      "PIV=V_m*math.sqrt(2)\n",

-      "I_Tr=I_m/(2)\n",

-      "I_TA=I_m/math.pi\n",

-      "\n",

-      "#Results\n",

-      "print(\"rms value of thyristor current=%.2f A\" %(fos*I_Tr))\n",

-      "print(\"avg value of thyristor current=%.3f A\" %(fos*I_TA))\n",

-      "print(\"voltage rating of thyristor=%.2f V\" %PIV)\n",

-      "print(\"rms value of diode current=%.3f A\" %(fos*I_Tr))\n",

-      "print(\"avg value of diode current=%.3f A\" %(fos*I_TA))\n",

-      "print(\"voltage rating of diode=%.2f V\" %PIV)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rms value of thyristor current=15.37 A\n",

-        "avg value of thyristor current=9.786 A\n",

-        "voltage rating of thyristor=325.27 V\n",

-        "rms value of diode current=15.372 A\n",

-        "avg value of diode current=9.786 A\n",

-        "voltage rating of diode=325.27 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 3

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 11.4, Page No 629"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=200.0\n",

-      "I=10.0\n",

-      "\n",

-      "#Calculations\n",

-      "R_L=V/I    \n",

-      "I_h=.005     #holding current\n",

-      "R2=V/I_h    \n",

-      "t_c=20*10**-6\n",

-      "fos=2 #factor of safety\n",

-      "C=t_c*fos/(R_L*math.log(2))    \n",

-      "\n",

-      "#Results\n",

-      "print(\"value of load resistance=%.0f ohm\" %R_L)\n",

-      "print(\"value of R2=%.0f kilo-ohm\" %(R2/1000))\n",

-      "print(\"value of C=%.3f uF\" %(C*10**6))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "value of load resistance=20 ohm\n",

-        "value of R2=40 kilo-ohm\n",

-        "value of C=2.885 uF\n"

-       ]

-      }

-     ],

-     "prompt_number": 4

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 11.5 Page No 646"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "u_r=10\n",

-      "f=10000.0 #Hz\n",

-      "p=4.0*10**-8 #ohm-m\n",

-      "\n",

-      "#Calculations\n",

-      "dl=(1/(2*math.pi))*math.sqrt(p*10**7/(u_r*f))    \n",

-      "l=0.12 #length of cylinder\n",

-      "t=20.0 #no of turns\n",

-      "I=100.0\n",

-      "H=t*I/l\n",

-      "P_s=2*math.pi*H**2*math.sqrt(u_r*f*p*10**-7)    \n",

-      "d=.02 #diameter\n",

-      "P_v=4*H**2*p/(d*dl)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"depth of heat of penetration=%.5f mm\" %(dl*1000))\n",

-      "print(\"heat generated per unit cylinder surface area=%.3f W/m**2\" %P_s)\n",

-      "print(\"heat generated per unit cylinder volume=%.0f W/m**3\" %P_v)\n",

-      " #answer of P_v varies as given in book as value of d is not taken as in formulae. "

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "depth of heat of penetration=0.31831 mm\n",

-        "heat generated per unit cylinder surface area=34906.585 W/m**2\n",

-        "heat generated per unit cylinder volume=6981317 W/m**3\n"

-       ]

-      }

-     ],

-     "prompt_number": 5

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 11.6 Page No 646"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "f=3000.0\n",

-      "\n",

-      "#Calculations\n",

-      "t_qmin=30.0*10**-6\n",

-      "f_r=f/(1-2*t_qmin*f)\n",

-      "R=0.06\n",

-      "L=20.0*10**-6\n",

-      "C=1/(L*((2*math.pi*f_r)**2+(R/(2*L))**2))    \n",

-      "\n",

-      "#Results\n",

-      "print(\"required capacitor size=%.4f F\" %(C*10**6))\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "required capacitor size=94.2215 F\n"

-       ]

-      }

-     ],

-     "prompt_number": 6

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Power_Electronics/Chapter11_3.ipynb b/_Power_Electronics/Chapter11_3.ipynb
deleted file mode 100755
index d2317d28..00000000
--- a/_Power_Electronics/Chapter11_3.ipynb
+++ /dev/null
@@ -1,299 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 11 : Some Applications"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 11.1, Page No 622"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=11000.0\n",

-      "V_ml=math.sqrt(2)*V_s\n",

-      "f=50.0\n",

-      "\n",

-      "#Calculations\n",

-      "w=2*math.pi*f\n",

-      "I_d=300\n",

-      "R_d=1\n",

-      "g=20 #g=gamma\n",

-      "a=math.degrees(math.acos(math.cos(math.radians(g))+math.pi/(3*V_ml)*I_d*R_d))    \n",

-      "L_s=.01\n",

-      "V_d=(3/math.pi)*((V_ml*math.cos(math.radians(a)))-w*L_s*I_d)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"firing angle=%.3f deg\" %a)\n",

-      "print(\"rectifier o/p voltage=%.1f V\" %V_d)\n",

-      "print(\"dc link voltage=%.3f V\" %(2*V_d/1000))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "firing angle=16.283 deg\n",

-        "rectifier o/p voltage=13359.3 V\n",

-        "dc link voltage=26.719 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 11.2, Page No 623"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_d=(200.0+200)*10**3\n",

-      "P=1000.0*10**6\n",

-      "\n",

-      "#Calculations\n",

-      "I_d=P/V_d\n",

-      " #each thristor conducts for 120deg for a periodicity of 360deg\n",

-      "a=0\n",

-      "V_d=200.0*10**3\n",

-      "V_ml=V_d*math.pi/(3*math.cos(math.radians(a)))\n",

-      "\n",

-      "#Results\n",

-      "print(\"rms current rating of thyristor=%.2f A\" %(I_d*math.sqrt(120/360)))\n",

-      "print(\"peak reverse voltage across each thyristor=%.2f kV\" %(V_ml/2/1000))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rms current rating of thyristor=0.00 A\n",

-        "peak reverse voltage across each thyristor=104.72 kV\n"

-       ]

-      }

-     ],

-     "prompt_number": 2

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 11.3 Page No 627"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_m=230.0\n",

-      "V_s=230/math.sqrt(2)\n",

-      "pf=0.8\n",

-      "P=2000.0\n",

-      "\n",

-      "#Calculations\n",

-      "I_m=P/(V_s*pf)\n",

-      "I_Tr=I_m/math.sqrt(2)\n",

-      "I_TA=2*I_m/math.pi\n",

-      "fos=2 #factor of safety\n",

-      "PIV=V_m*math.sqrt(2)\n",

-      "I_Tr=I_m/(2)\n",

-      "I_TA=I_m/math.pi\n",

-      "\n",

-      "#Results\n",

-      "print(\"rms value of thyristor current=%.2f A\" %(fos*I_Tr))\n",

-      "print(\"avg value of thyristor current=%.3f A\" %(fos*I_TA))\n",

-      "print(\"voltage rating of thyristor=%.2f V\" %PIV)\n",

-      "print(\"rms value of diode current=%.3f A\" %(fos*I_Tr))\n",

-      "print(\"avg value of diode current=%.3f A\" %(fos*I_TA))\n",

-      "print(\"voltage rating of diode=%.2f V\" %PIV)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rms value of thyristor current=15.37 A\n",

-        "avg value of thyristor current=9.786 A\n",

-        "voltage rating of thyristor=325.27 V\n",

-        "rms value of diode current=15.372 A\n",

-        "avg value of diode current=9.786 A\n",

-        "voltage rating of diode=325.27 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 3

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 11.4, Page No 629"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=200.0\n",

-      "I=10.0\n",

-      "\n",

-      "#Calculations\n",

-      "R_L=V/I    \n",

-      "I_h=.005     #holding current\n",

-      "R2=V/I_h    \n",

-      "t_c=20*10**-6\n",

-      "fos=2 #factor of safety\n",

-      "C=t_c*fos/(R_L*math.log(2))    \n",

-      "\n",

-      "#Results\n",

-      "print(\"value of load resistance=%.0f ohm\" %R_L)\n",

-      "print(\"value of R2=%.0f kilo-ohm\" %(R2/1000))\n",

-      "print(\"value of C=%.3f uF\" %(C*10**6))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "value of load resistance=20 ohm\n",

-        "value of R2=40 kilo-ohm\n",

-        "value of C=2.885 uF\n"

-       ]

-      }

-     ],

-     "prompt_number": 4

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 11.5 Page No 646"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "u_r=10\n",

-      "f=10000.0 #Hz\n",

-      "p=4.0*10**-8 #ohm-m\n",

-      "\n",

-      "#Calculations\n",

-      "dl=(1/(2*math.pi))*math.sqrt(p*10**7/(u_r*f))    \n",

-      "l=0.12 #length of cylinder\n",

-      "t=20.0 #no of turns\n",

-      "I=100.0\n",

-      "H=t*I/l\n",

-      "P_s=2*math.pi*H**2*math.sqrt(u_r*f*p*10**-7)    \n",

-      "d=.02 #diameter\n",

-      "P_v=4*H**2*p/(d*dl)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"depth of heat of penetration=%.5f mm\" %(dl*1000))\n",

-      "print(\"heat generated per unit cylinder surface area=%.3f W/m**2\" %P_s)\n",

-      "print(\"heat generated per unit cylinder volume=%.0f W/m**3\" %P_v)\n",

-      " #answer of P_v varies as given in book as value of d is not taken as in formulae. "

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "depth of heat of penetration=0.31831 mm\n",

-        "heat generated per unit cylinder surface area=34906.585 W/m**2\n",

-        "heat generated per unit cylinder volume=6981317 W/m**3\n"

-       ]

-      }

-     ],

-     "prompt_number": 5

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 11.6 Page No 646"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "f=3000.0\n",

-      "\n",

-      "#Calculations\n",

-      "t_qmin=30.0*10**-6\n",

-      "f_r=f/(1-2*t_qmin*f)\n",

-      "R=0.06\n",

-      "L=20.0*10**-6\n",

-      "C=1/(L*((2*math.pi*f_r)**2+(R/(2*L))**2))    \n",

-      "\n",

-      "#Results\n",

-      "print(\"required capacitor size=%.4f F\" %(C*10**6))\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "required capacitor size=94.2215 F\n"

-       ]

-      }

-     ],

-     "prompt_number": 6

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Power_Electronics/Chapter11_4.ipynb b/_Power_Electronics/Chapter11_4.ipynb
deleted file mode 100755
index d2317d28..00000000
--- a/_Power_Electronics/Chapter11_4.ipynb
+++ /dev/null
@@ -1,299 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 11 : Some Applications"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 11.1, Page No 622"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=11000.0\n",

-      "V_ml=math.sqrt(2)*V_s\n",

-      "f=50.0\n",

-      "\n",

-      "#Calculations\n",

-      "w=2*math.pi*f\n",

-      "I_d=300\n",

-      "R_d=1\n",

-      "g=20 #g=gamma\n",

-      "a=math.degrees(math.acos(math.cos(math.radians(g))+math.pi/(3*V_ml)*I_d*R_d))    \n",

-      "L_s=.01\n",

-      "V_d=(3/math.pi)*((V_ml*math.cos(math.radians(a)))-w*L_s*I_d)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"firing angle=%.3f deg\" %a)\n",

-      "print(\"rectifier o/p voltage=%.1f V\" %V_d)\n",

-      "print(\"dc link voltage=%.3f V\" %(2*V_d/1000))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "firing angle=16.283 deg\n",

-        "rectifier o/p voltage=13359.3 V\n",

-        "dc link voltage=26.719 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 11.2, Page No 623"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_d=(200.0+200)*10**3\n",

-      "P=1000.0*10**6\n",

-      "\n",

-      "#Calculations\n",

-      "I_d=P/V_d\n",

-      " #each thristor conducts for 120deg for a periodicity of 360deg\n",

-      "a=0\n",

-      "V_d=200.0*10**3\n",

-      "V_ml=V_d*math.pi/(3*math.cos(math.radians(a)))\n",

-      "\n",

-      "#Results\n",

-      "print(\"rms current rating of thyristor=%.2f A\" %(I_d*math.sqrt(120/360)))\n",

-      "print(\"peak reverse voltage across each thyristor=%.2f kV\" %(V_ml/2/1000))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rms current rating of thyristor=0.00 A\n",

-        "peak reverse voltage across each thyristor=104.72 kV\n"

-       ]

-      }

-     ],

-     "prompt_number": 2

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 11.3 Page No 627"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_m=230.0\n",

-      "V_s=230/math.sqrt(2)\n",

-      "pf=0.8\n",

-      "P=2000.0\n",

-      "\n",

-      "#Calculations\n",

-      "I_m=P/(V_s*pf)\n",

-      "I_Tr=I_m/math.sqrt(2)\n",

-      "I_TA=2*I_m/math.pi\n",

-      "fos=2 #factor of safety\n",

-      "PIV=V_m*math.sqrt(2)\n",

-      "I_Tr=I_m/(2)\n",

-      "I_TA=I_m/math.pi\n",

-      "\n",

-      "#Results\n",

-      "print(\"rms value of thyristor current=%.2f A\" %(fos*I_Tr))\n",

-      "print(\"avg value of thyristor current=%.3f A\" %(fos*I_TA))\n",

-      "print(\"voltage rating of thyristor=%.2f V\" %PIV)\n",

-      "print(\"rms value of diode current=%.3f A\" %(fos*I_Tr))\n",

-      "print(\"avg value of diode current=%.3f A\" %(fos*I_TA))\n",

-      "print(\"voltage rating of diode=%.2f V\" %PIV)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rms value of thyristor current=15.37 A\n",

-        "avg value of thyristor current=9.786 A\n",

-        "voltage rating of thyristor=325.27 V\n",

-        "rms value of diode current=15.372 A\n",

-        "avg value of diode current=9.786 A\n",

-        "voltage rating of diode=325.27 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 3

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 11.4, Page No 629"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=200.0\n",

-      "I=10.0\n",

-      "\n",

-      "#Calculations\n",

-      "R_L=V/I    \n",

-      "I_h=.005     #holding current\n",

-      "R2=V/I_h    \n",

-      "t_c=20*10**-6\n",

-      "fos=2 #factor of safety\n",

-      "C=t_c*fos/(R_L*math.log(2))    \n",

-      "\n",

-      "#Results\n",

-      "print(\"value of load resistance=%.0f ohm\" %R_L)\n",

-      "print(\"value of R2=%.0f kilo-ohm\" %(R2/1000))\n",

-      "print(\"value of C=%.3f uF\" %(C*10**6))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "value of load resistance=20 ohm\n",

-        "value of R2=40 kilo-ohm\n",

-        "value of C=2.885 uF\n"

-       ]

-      }

-     ],

-     "prompt_number": 4

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 11.5 Page No 646"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "u_r=10\n",

-      "f=10000.0 #Hz\n",

-      "p=4.0*10**-8 #ohm-m\n",

-      "\n",

-      "#Calculations\n",

-      "dl=(1/(2*math.pi))*math.sqrt(p*10**7/(u_r*f))    \n",

-      "l=0.12 #length of cylinder\n",

-      "t=20.0 #no of turns\n",

-      "I=100.0\n",

-      "H=t*I/l\n",

-      "P_s=2*math.pi*H**2*math.sqrt(u_r*f*p*10**-7)    \n",

-      "d=.02 #diameter\n",

-      "P_v=4*H**2*p/(d*dl)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"depth of heat of penetration=%.5f mm\" %(dl*1000))\n",

-      "print(\"heat generated per unit cylinder surface area=%.3f W/m**2\" %P_s)\n",

-      "print(\"heat generated per unit cylinder volume=%.0f W/m**3\" %P_v)\n",

-      " #answer of P_v varies as given in book as value of d is not taken as in formulae. "

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "depth of heat of penetration=0.31831 mm\n",

-        "heat generated per unit cylinder surface area=34906.585 W/m**2\n",

-        "heat generated per unit cylinder volume=6981317 W/m**3\n"

-       ]

-      }

-     ],

-     "prompt_number": 5

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 11.6 Page No 646"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "f=3000.0\n",

-      "\n",

-      "#Calculations\n",

-      "t_qmin=30.0*10**-6\n",

-      "f_r=f/(1-2*t_qmin*f)\n",

-      "R=0.06\n",

-      "L=20.0*10**-6\n",

-      "C=1/(L*((2*math.pi*f_r)**2+(R/(2*L))**2))    \n",

-      "\n",

-      "#Results\n",

-      "print(\"required capacitor size=%.4f F\" %(C*10**6))\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "required capacitor size=94.2215 F\n"

-       ]

-      }

-     ],

-     "prompt_number": 6

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Power_Electronics/Chapter12.ipynb b/_Power_Electronics/Chapter12.ipynb
deleted file mode 100755
index f8605d69..00000000
--- a/_Power_Electronics/Chapter12.ipynb
+++ /dev/null
@@ -1,1997 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 12 : Electic Drives"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.1, Page No 658"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "T_e=15.0 #Nm\n",

-      "K_m=0.5 #V-s/rad\n",

-      "I_a=T_e/K_m\n",

-      "n_m=1000.0\n",

-      "\n",

-      "#Calculations\n",

-      "w_m=2*math.pi*n_m/60\n",

-      "E_a=K_m*w_m\n",

-      "r_a=0.7\n",

-      "V_t=E_a+I_a*r_a\n",

-      "V_s=230.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "a=math.degrees(math.acos(2*math.pi*V_t/V_m-1))\n",

-      "print(\"firing angle delay=%.3f deg\" %a)\n",

-      "I_Tr=I_a*math.sqrt((180-a)/360)    \n",

-      "print(\"rms value of thyristor current=%.3f A\" %I_Tr)\n",

-      "I_fdr=I_a*math.sqrt((180+a)/360)    \n",

-      "print(\"rms value of freewheeling diode current=%.3f A\" %I_fdr)\n",

-      "pf=V_t*I_a/(V_s*I_Tr)  \n",

-      "\n",

-      "#Results  \n",

-      "print(\"input power factor=%.4f\" %pf)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "firing angle delay=65.349 deg\n",

-        "rms value of thyristor current=16.930 A\n",

-        "rms value of freewheeling diode current=24.766 A\n",

-        "input power factor=0.5652\n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.2, Page No 660"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=230.0\n",

-      "E=150.0\n",

-      "R=8.0\n",

-      "\n",

-      "#Calculations\n",

-      "th1=math.sin(math.radians(E/(math.sqrt(2)*V)))\n",

-      "I_o=(1/(2*math.pi*R))*(2*math.sqrt(2)*230*math.cos(math.radians(th1))-E*(math.pi-2*th1*math.pi/180))    \n",

-      "P=E*I_o    \n",

-      "I_or=math.sqrt((1/(2*math.pi*R**2))*((V**2+E**2)*(math.pi-2*th1*math.pi/180)+V**2*math.sin(math.radians(2*th1))-4*math.sqrt(2)*V*E*math.cos(math.radians(th1))))\n",

-      "P_r=I_or**2*R    \n",

-      "pf=(P+P_r)/(V*I_or)\n",

-      "\n",

-      "#Results\n",

-      "print(\"avg charging curent=%.4f A\" %I_o)\n",

-      "print(\"power supplied to the battery=%.2f W\" %P)\n",

-      "print(\"power dissipated by the resistor=%.3f W\" %P_r)    \n",

-      "print(\"supply pf=%.3f\" %pf)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "avg charging curent=3.5679 A\n",

-        "power supplied to the battery=535.18 W\n",

-        "power dissipated by the resistor=829.760 W\n",

-        "supply pf=0.583\n"

-       ]

-      }

-     ],

-     "prompt_number": 2

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.3 Page No 661"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variablesV_s=250\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "a=30.0\n",

-      "k=0.03 #Nm/A**2\n",

-      "n_m=1000.0\n",

-      "\n",

-      "#Calculations\n",

-      "w_m=2*math.pi*n_m/60\n",

-      "r=.2 #r_a+r_s\n",

-      "V_t=V_m/math.pi*(1+math.cos(math.radians(a)))\n",

-      "I_a=V_t/(k*w_m+r)   \n",

-      "print(\"motor armature current=%.2f A\" %I_a)\n",

-      "T_e=k*I_a**2    \n",

-      "print(\"motor torque=%.3f Nm\" %T_e)\n",

-      "I_sr=I_a*math.sqrt((180-a)/180)\n",

-      "pf=(V_t*I_a)/(V_s*I_sr)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"input power factor=%.2f\" %pf)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "motor armature current=57.82 A\n",

-        "motor torque=100.285 Nm\n",

-        "input power factor=0.92\n"

-       ]

-      }

-     ],

-     "prompt_number": 3

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.4, Page No 663"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=400.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "V_f=2*V_m/math.pi\n",

-      "r_f=200.0\n",

-      "I_f=V_f/r_f\n",

-      "T_e=85.0\n",

-      "K_a=0.8\n",

-      "\n",

-      "#Calculations\n",

-      "I_a=T_e/(I_f*K_a)    \n",

-      "print(\"rated armature current=%.2f A\" %I_a)\n",

-      "n_m=1200.0\n",

-      "w_m=2*math.pi*n_m/60\n",

-      "r_a=0.2\n",

-      "V_t=K_a*I_f*w_m+I_a*r_a\n",

-      "a=math.degrees(math.acos(V_t*math.pi/(2*V_m)))\n",

-      "print(\"firing angle delay=%.2f deg\" %a)\n",

-      "E_a=V_t\n",

-      "w_mo=E_a/(K_a*I_f)\n",

-      "N=60*w_mo/(2*math.pi)\n",

-      "reg=((N-n_m)/n_m)*100    \n",

-      "print(\"speed regulation at full load=%.2f\" %reg)\n",

-      "I_ar=I_a\n",

-      "pf=(V_t*I_a)/(V_s*I_ar)    \n",

-      "print(\"input power factor of armature convertor=%.4f\" %pf)\n",

-      "I_fr=I_f\n",

-      "I_sr=math.sqrt(I_fr**2+I_ar**2)\n",

-      "VA=I_sr*V_s\n",

-      "P=V_t*I_a+V_f*I_f\n",

-      "\n",

-      "#Results\n",

-      "print(\"input power factor of drive=%.4f\" %(P/VA))\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rated armature current=59.01 A\n",

-        "firing angle delay=57.63 deg\n",

-        "speed regulation at full load=6.52\n",

-        "input power factor of armature convertor=0.4821\n",

-        "input power factor of drive=0.5093\n"

-       ]

-      }

-     ],

-     "prompt_number": 4

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.5 Page No 664"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=400.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "V_f=2*V_m/math.pi\n",

-      "\n",

-      "#Calculations\n",

-      "a1=math.degrees(math.acos(V_t*math.pi/(2*V_m))) \n",

-      "print(\"delay angle of field converter=%.0f deg\" %a1)\n",

-      "r_f=200.0\n",

-      "I_f=V_f/r_f\n",

-      "T_e=85.0\n",

-      "K_a=0.8\n",

-      "I_a=T_e/(I_f*K_a)\n",

-      "n_m=1200.0\n",

-      "w_m=2*math.pi*n_m/60\n",

-      "r_a=0.1\n",

-      "I_a=50.0\n",

-      "V_t=-K_a*I_f*w_m+I_a*r_a\n",

-      "a=math.degrees(math.acos(V_t*math.pi/(2*V_m)))\n",

-      "\n",

-      "#Results\n",

-      "print(\"firing angle delay of armature converter=%.3f deg\" %a)\n",

-      "print(\"power fed back to ac supply=%.0f W\" %(-V_t*I_a))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "delay angle of field converter=58 deg\n",

-        "firing angle delay of armature converter=119.260 deg\n",

-        "power fed back to ac supply=8801 W\n"

-       ]

-      }

-     ],

-     "prompt_number": 5

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.6 Page No 665"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_t=220.0\n",

-      "n_m=1500.0\n",

-      "w_m=2*math.pi*n_m/60\n",

-      "I_a=10.0\n",

-      "r_a=1.0\n",

-      "\n",

-      "#Calculations\n",

-      "K_m=(V_t-I_a*r_a)/(w_m)\n",

-      "T=5.0\n",

-      "I_a=T/K_m\n",

-      "V_s=230.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "a=30.0\n",

-      "V_t=2*V_m*math.cos(math.radians(a))/math.pi\n",

-      "w_m=(V_t-I_a*r_a)/K_m\n",

-      "N=w_m*60/(2*math.pi)    \n",

-      "\n",

-      "print(\"motor speed=%.2f rpm\" %N)\n",

-      "a=45\n",

-      "n_m=1000\n",

-      "w_m=2*math.pi*n_m/60\n",

-      "V_t=2*V_m*math.cos(math.radians(a))/math.pi\n",

-      "I_a=(V_t-K_m*w_m)/r_a\n",

-      "T_e=K_m*I_a    \n",

-      "\n",

-      "#Results\n",

-      "print(\"torque developed=%.3f Nm\" %T_e)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "motor speed=1254.22 rpm\n",

-        "torque developed=8.586 Nm\n"

-       ]

-      }

-     ],

-     "prompt_number": 6

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.7, Page No 666"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_t=220.0\n",

-      "n_m=1000.0\n",

-      "w_m=2*math.pi*n_m/60\n",

-      "I_a=60.0\n",

-      "r_a=.1\n",

-      "\n",

-      "#Calculations\n",

-      "K_m=(V_t-I_a*r_a)/(w_m)\n",

-      "V_s=230\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "print(\"for 600rpm speed\")\n",

-      "n_m=600.0\n",

-      "w_m=2*math.pi*n_m/60\n",

-      "a=math.degrees(math.acos((K_m*w_m+I_a*r_a)*math.pi/(2*V_m))) \n",

-      "print(\"firing angle=%.3f deg\" %a)\n",

-      "print(\"for -500rpm speed\")\n",

-      "n_m=-500.0\n",

-      "w_m=2*math.pi*n_m/60\n",

-      "a=math.degrees(math.acos((K_m*w_m+I_a*r_a)*math.pi/(2*V_m)))\n",

-      "print(\"firing angle=%.2f deg\" %a)\n",

-      "I_a=I_a/2\n",

-      "a=150\n",

-      "V_t=2*V_m*math.cos(math.radians(a))/math.pi\n",

-      "w_m=(V_t-I_a*r_a)/K_m\n",

-      "N=w_m*60/(2*math.pi)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"motor speed=%.3f rpm\" %N)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for 600rpm speed\n",

-        "firing angle=49.530 deg\n",

-        "for -500rpm speed\n",

-        "firing angle=119.19 deg\n",

-        "motor speed=-852.011 rpm\n"

-       ]

-      }

-     ],

-     "prompt_number": 7

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.8 Page No 672"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "K_m=1.5\n",

-      "T_e=50.0\n",

-      "I_a=T_e/K_m\n",

-      "r_a=0.9\n",

-      "a=45.0\n",

-      "V_s=415.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_ml=math.sqrt(2)*V_s\n",

-      "w_m=((3*V_ml*(1+math.cos(math.radians(a)))/(2*math.pi))-I_a*r_a)/K_m\n",

-      "N=w_m*60/(2*math.pi)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"motor speed=%.2f rpm\" %N)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "motor speed=2854.42 rpm\n"

-       ]

-      }

-     ],

-     "prompt_number": 8

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.9 Page No 672"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variablesV_t=600\n",

-      "n_m=1500.0\n",

-      "w_m=2*math.pi*n_m/60\n",

-      "I_a=80.0\n",

-      "r_a=1.0\n",

-      "\n",

-      "#Calculations\n",

-      "K_m=(V_t-I_a*r_a)/(w_m)\n",

-      "V_s=400.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "print(\"for firing angle=45deg and speed=1200rpm\")\n",

-      "a=45.0\n",

-      "n_m=1200.0\n",

-      "w_m=2*math.pi*n_m/60\n",

-      "I_a=(3*V_m*(1+math.cos(math.radians(a)))/(2*math.pi)-K_m*w_m)/r_a\n",

-      "I_sr=I_a*math.sqrt(2/3)    \n",

-      "print(\"rms value of source current=%.3f A\" %I_sr)\n",

-      "print(\"rms value of thyristor current=%.3f A\" %(I_a*math.sqrt(1/3)))\n",

-      "print(\"avg value of thyristor current=%.2f A\" %I_a*(1/3))\n",

-      "pf=(3/(2*math.pi)*(1+math.cos(math.radians(a))))    \n",

-      "print(\"input power factor=%.3f\" %pf)\n",

-      "\n",

-      "print(\"for firing angle=90deg and speed=700rpm\")\n",

-      "a=90\n",

-      "n_m=700\n",

-      "w_m=2*math.pi*n_m/60\n",

-      "I_a=(3*V_m*(1+math.cos(math.radians(a)))/(2*math.pi)-K_m*w_m)/r_a\n",

-      "I_sr=I_a*math.sqrt(90/180)    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"rms value of source current=%.3f A\" %I_sr)\n",

-      "print(\"rms value of thyristor current=%.3f A\" %(I_a*math.sqrt(90.0/360)))\n",

-      "print(\"avg value of thyristor current=%.3f A\" %I_a*(1/3))\n",

-      "pf=(math.sqrt(6)/(2*math.pi)*(1+math.cos(math.radians(a))))*math.sqrt(180/(180-a))    \n",

-      "print(\"input power factor=%.4f\" %pf)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for firing angle=45deg and speed=1200rpm\n",

-        "rms value of source current=0.000 A\n",

-        "rms value of thyristor current=0.000 A\n",

-        "\n",

-        "input power factor=0.815\n",

-        "for firing angle=90deg and speed=700rpm\n",

-        "rms value of source current=0.000 A\n",

-        "rms value of thyristor current=195.558 A\n",

-        "\n",

-        "input power factor=0.5513\n"

-       ]

-      }

-     ],

-     "prompt_number": 9

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.10 Page No 676"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=400.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "a=30\n",

-      "V_t=3*V_m*math.cos(math.radians(a))/math.pi\n",

-      "I_a=21.0\n",

-      "r_a=.1\n",

-      "V_d=2.0\n",

-      "K_m=1.6\n",

-      "\n",

-      "#Calculations\n",

-      "w_m=(V_t-I_a*r_a-V_d)/K_m\n",

-      "N=w_m*60/(2*math.pi)    \n",

-      "print(\"speed of motor=%.1f rpm\" %N)\n",

-      "\n",

-      "N=2000\n",

-      "w_m=2*math.pi*N/60\n",

-      "I_a=210\n",

-      "V_t=K_m*w_m+I_a*r_a+V_d\n",

-      "a=math.degrees(math.acos(V_t*math.pi/(3*V_m)))\n",

-      "print(\"firing angle=%.2f deg\" %a)\n",

-      "I_sr=I_a*math.sqrt(2.0/3.0)\n",

-      "pf=V_t*I_a/(math.sqrt(3)*V_s*I_sr)    \n",

-      "print(\"supply power factor=%.3f\" %pf)\n",

-      "\n",

-      "I_a=21\n",

-      "w_m=(V_t-I_a*r_a-V_d)/K_m\n",

-      "n=w_m*60/(2*math.pi)\n",

-      "reg=(n-N)/N*100    \n",

-      "\n",

-      "#Results\n",

-      "print(\"speed regulation(percent)=%.2f\" %reg)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "speed of motor=2767.6 rpm\n",

-        "firing angle=48.48 deg\n",

-        "supply power factor=0.633\n",

-        "speed regulation(percent)=5.64\n"

-       ]

-      }

-     ],

-     "prompt_number": 10

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.11, Page No 677"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_t=230.0\n",

-      "V_l=V_t*math.pi/(3*math.sqrt(2))\n",

-      "V_ph=V_l/math.sqrt(3)\n",

-      "V_in=400     #per phase voltage input\n",

-      "\n",

-      "#Calculations\n",

-      "N1=1500.0\n",

-      "I_a1=20.0\n",

-      "r_a1=.6\n",

-      "E_a1=V_t-I_a1*r_a1\n",

-      "n1=1000.0\n",

-      "E_a2=E_a1/1500.0*1000.0\n",

-      "V_t1=E_a1+I_a1*r_a1\n",

-      "a1=math.degrees(math.acos(V_t1*math.pi/(3*math.sqrt(2.0)*V_l)))\n",

-      "I_a2=.5*I_a1\n",

-      "n2=-900.0\n",

-      "V_t2=n2*E_a2/N1+I_a2*r_a1\n",

-      "a2=math.degrees(math.acos(V_t2*math.pi/(3*math.sqrt(2)*V_l))) \n",

-      "\n",

-      "#Results\n",

-      "print(\"transformer phase turns ratio=%.3f\" %(V_in/V_ph))\n",

-      "print(\"for motor running at 1000rpm at rated torque\")\n",

-      "print(\"firing angle delay=%.2f deg\" %a1)\n",

-      "print(\"for motor running at -900rpm at half of rated torque\")\n",

-      "print(\"firing angle delay=%.3f deg\" %a2)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "transformer phase turns ratio=4.068\n",

-        "for motor running at 1000rpm at rated torque\n",

-        "firing angle delay=0.00 deg\n",

-        "for motor running at -900rpm at half of rated torque\n",

-        "firing angle delay=110.674 deg\n"

-       ]

-      }

-     ],

-     "prompt_number": 11

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.12, Page No 678"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variablesV_s=400\n",

-      "V_ml=math.sqrt(2)*V_s\n",

-      "V_f=3*V_ml/math.pi\n",

-      "R_f=300.0\n",

-      "I_f=V_f/R_f\n",

-      "T_e=60.0\n",

-      "k=1.1\n",

-      "\n",

-      "#Calculations\n",

-      "I_a=T_e/(k*I_f)\n",

-      "N1=1000.0\n",

-      "w_m1=2*math.pi*N1/60\n",

-      "r_a1=.3\n",

-      "V_t1=k*I_f*w_m1+I_a*r_a1\n",

-      "a1=math.degrees(math.acos(V_f*math.pi/(3*V_ml)))\n",

-      "N2=3000\n",

-      "w_m2=2*math.pi*N/60\n",

-      "a2=0\n",

-      "V_t2=3*V_ml*math.cos(math.radians(a))/math.pi\n",

-      "I_f2=(V_t2-I_a*r_a)/(w_m2*k)\n",

-      "V_f2=I_f2*R_f\n",

-      "a2=math.degrees(math.acos(V_f2*math.pi/(3*V_ml)))\n",

-      "\n",

-      "#Results\n",

-      "print(\"firing angle=%.3f deg\" %a)\n",

-      "print(\"firing angle=%.3f deg\" %a)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "firing angle=48.477 deg\n",

-        "firing angle=48.477 deg\n"

-       ]

-      }

-     ],

-     "prompt_number": 12

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.13, Page No 679"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      " #after calculating\n",

-      " #t=w_m/6000-math.pi/360\n",

-      "\n",

-      "N=1000.0\n",

-      "\n",

-      "#Calculations\n",

-      "w_m=2*math.pi*N/60\n",

-      "t=w_m/6000-math.pi/360    \n",

-      "\n",

-      "#Results\n",

-      "print(\"time reqd=%.2f s\" %t)\n",

-      " #printing mistake in the answer in book"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "time reqd=0.01 s\n"

-       ]

-      }

-     ],

-     "prompt_number": 13

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.14, Page No 679"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "I_a=1.0 #supposition\n",

-      "a=60.0\n",

-      "\n",

-      "#Calculations\n",

-      "I_s1=2*math.sqrt(2)/math.pi*I_a*math.sin(math.radians(a))\n",

-      "I_s3=2*math.sqrt(2)/(3*math.pi)*I_a*math.sin(math.radians(3*a))\n",

-      "I_s5=2*math.sqrt(2)/(5*math.pi)*I_a*math.sin(math.radians(5*a))\n",

-      "per3=I_s3/I_s1*100    \n",

-      "print(\"percent of 3rd harmonic current in fundamental=%.2f\" %per3)\n",

-      "per5=I_s5/I_s1*100    \n",

-      "\n",

-      "#Results\n",

-      "print(\"percent of 5th harmonic current in fundamental=%.2f\" %per5)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "percent of 3rd harmonic current in fundamental=0.00\n",

-        "percent of 5th harmonic current in fundamental=-20.00\n"

-       ]

-      }

-     ],

-     "prompt_number": 14

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.15, Page No 680"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "I_a=60.0\n",

-      "I_TA=I_a/3    \n",

-      "\n",

-      "#Calculations\n",

-      "print(\"avg thyristor current=%.0f A\" %I_TA)\n",

-      "I_Tr=I_a/math.sqrt(3)    \n",

-      "print(\"rms thyristor current=%.3f A\" %I_Tr)\n",

-      "V_s=400\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "I_sr=I_a*math.sqrt(2.0/3)\n",

-      "a=150\n",

-      "V_t=3*V_m*math.cos(math.radians(a))/math.pi\n",

-      "pf=V_t*I_a/(math.sqrt(3)*V_s*I_sr)    \n",

-      "print(\"power factor of ac source=%.3f\" %pf)\n",

-      "\n",

-      "r_a=0.5\n",

-      "K_m=2.4\n",

-      "w_m=(V_t-I_a*r_a)/K_m\n",

-      "N=w_m*60/(2*math.pi)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"Speed of motor=%.2f rpm\" %N)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "avg thyristor current=20 A\n",

-        "rms thyristor current=34.641 A\n",

-        "power factor of ac source=-0.827\n",

-        "Speed of motor=-1980.76 rpm\n"

-       ]

-      }

-     ],

-     "prompt_number": 15

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.16, Page No 685"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "I_a=300.0\n",

-      "V_s=600.0\n",

-      "a=0.6\n",

-      "V_t=a*V_s\n",

-      "P=V_t*I_a    \n",

-      "\n",

-      "#Calculations\n",

-      "print(\"input power from source=%.0f kW\" %(P/1000))\n",

-      "R_eq=V_s/(a*I_a)    \n",

-      "print(\"equivalent input resistance=%.3f ohm\" %R_eq)\n",

-      "k=.004\n",

-      "R=.04+.06\n",

-      "w_m=(a*V_s-I_a*R)/(k*I_a)\n",

-      "N=w_m*60/(2*math.pi)    \n",

-      "print(\"motor speed=%.1f rpm\" %N)\n",

-      "T_e=k*I_a**2    \n",

-      "\n",

-      "#Results\n",

-      "print(\"motor torque=%.0f Nm\" %T_e)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "input power from source=108 kW\n",

-        "equivalent input resistance=3.333 ohm\n",

-        "motor speed=2626.1 rpm\n",

-        "motor torque=360 Nm\n"

-       ]

-      }

-     ],

-     "prompt_number": 16

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.17, Page No 686"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "T_on=10.0\n",

-      "T_off=15.0\n",

-      "\n",

-      "#Calculations\n",

-      "a=T_on/(T_on+T_off)\n",

-      "V_s=230.0\n",

-      "V_t=a*V_s\n",

-      "r_a=3\n",

-      "K_m=.5\n",

-      "N=1500\n",

-      "w_m=2*math.pi*N/60\n",

-      "I_a=(V_t-K_m*w_m)/r_a    \n",

-      "\n",

-      "#Results\n",

-      "print(\"motor load current=%.3f A\" %I_a)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "motor load current=4.487 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 17

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.18, Page No 686"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "w_m=0    \n",

-      "print(\"lower limit of speed control=%.0f rpm\" %w_m)\n",

-      "I_a=25.0\n",

-      "r_a=.2\n",

-      "V_s=220\n",

-      "K_m=0.08\n",

-      "\n",

-      "#Calculations\n",

-      "a=(K_m*w_m+I_a*r_a)/V_s    \n",

-      "print(\"lower limit of duty cycle=%.3f\" %a)\n",

-      "a=1    \n",

-      "print(\"upper limit of duty cycle=%.0f\" %a)\n",

-      "w_m=(a*V_s-I_a*r_a)/K_m    \n",

-      "\n",

-      "#Results\n",

-      "print(\"upper limit of speed control=%.1f rpm\" %w_m)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "lower limit of speed control=0 rpm\n",

-        "lower limit of duty cycle=0.023\n",

-        "upper limit of duty cycle=1\n",

-        "upper limit of speed control=2687.5 rpm\n"

-       ]

-      }

-     ],

-     "prompt_number": 18

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.21, Page No 691"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "a=0.6\n",

-      "V_s=400.0\n",

-      "V_t=(1-a)*V_s\n",

-      "I_a=300.0\n",

-      "P=V_t*I_a  \n",

-      "\n",

-      "#Calculations  \n",

-      "print(\"power returned=%.0f kW\" %(P/1000))\n",

-      "r_a=.2\n",

-      "K_m=1.2\n",

-      "R_eq=(1-a)*V_s/I_a+r_a    \n",

-      "print(\"equivalent load resistance=%.4f ohm\" %R_eq)\n",

-      "w_mn=I_a*r_a/K_m\n",

-      "N=w_mn*60/(2*math.pi)    \n",

-      "print(\"min braking speed=%.2f rpm\" %N)\n",

-      "w_mx=(V_s+I_a*r_a)/K_m\n",

-      "N=w_mx*60/(2*math.pi)    \n",

-      "print(\"max braking speed=%.1f rpm\" %N)\n",

-      "w_m=(V_t+I_a*r_a)/K_m\n",

-      "N=w_m*60/(2*math.pi)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"max braking speed=%.1f rpm\" %N)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "power returned=48 kW\n",

-        "equivalent load resistance=0.7333 ohm\n",

-        "min braking speed=477.46 rpm\n",

-        "max braking speed=3660.6 rpm\n",

-        "max braking speed=1750.7 rpm\n"

-       ]

-      }

-     ],

-     "prompt_number": 19

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.22, Page No 699"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "N=1500.0\n",

-      "\n",

-      "#Calculations\n",

-      "print(\"when speed=1455rpm\")\n",

-      "n=1455.0\n",

-      "s1=(N-n)/N\n",

-      "r=math.sqrt(1/3)*(2/3)/(math.sqrt(s1)*(1-s1))    \n",

-      "print(\"I_2mx/I_2r=%.3f\" %r)\n",

-      "print(\"when speed=1350rpm\")\n",

-      "n=1350\n",

-      "s1=(N-n)/N\n",

-      "r=math.sqrt(1/3)*(2/3)/(math.sqrt(s1)*(1-s1))    \n",

-      "\n",

-      "#Results\n",

-      "print(\"I_2mx/I_2r=%.3f\" %r)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "when speed=1455rpm\n",

-        "I_2mx/I_2r=0.000\n",

-        "when speed=1350rpm\n",

-        "I_2mx/I_2r=0.000\n"

-       ]

-      }

-     ],

-     "prompt_number": 20

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.24, Page No 705"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V1=400.0\n",

-      "r1=0.6\n",

-      "r2=0.4\n",

-      "s=1.0\n",

-      "x1=1.6\n",

-      "x2=1.6\n",

-      "\n",

-      "#Calculations\n",

-      "print(\"at starting in normal conditions\")\n",

-      "I_n=V1/math.sqrt((r1+r2/s)**2+(x1+x2)**2)    \n",

-      "print(\"current=%.2f A\" %I_n)\n",

-      "pf=(r1+r2)/math.sqrt((r1+r2/s)**2+(x1+x2)**2)    \n",

-      "print(\"pf=%.4f\" %pf)\n",

-      "f1=50\n",

-      "w_s=4*math.pi*f1/4\n",

-      "T_en=(3/w_s)*I_n**2*(r2/s)    \n",

-      "print(\"\\nTorque developed=%.2f Nm\" %T_en)\n",

-      "print(\"motor is operated with DOL starting\")\n",

-      "I_d=V1/2/math.sqrt((r1+r2/s)**2+((x1+x2)/2)**2)    \n",

-      "print(\"current=%.0f A\" %I_d)\n",

-      "pf=(r1+r2)/math.sqrt((r1+r2/s)**2+((x1+x2)/2)**2)    \n",

-      "print(\"pf=%.2f\" %pf)\n",

-      "f1=25\n",

-      "w_s=4*math.pi*f1/4\n",

-      "T_ed=(3/w_s)*I_d**2*(r2/s)    \n",

-      "print(\"Torque developed=%.3f Nm\" %T_ed)\n",

-      "print(\"at max torque conditions\")\n",

-      "s_mn=r2/math.sqrt((r1)**2+((x1+x2))**2)\n",

-      "I_n=V1/math.sqrt((r1+r2/s_mn)**2+(x1+x2)**2)    \n",

-      "print(\"current=%.3f A\" %I_n)\n",

-      "pf=(r1+r2/s_mn)/math.sqrt((r1+r2/s_mn)**2+(x1+x2)**2)    \n",

-      "print(\"pf=%.4f\" %pf)\n",

-      "f1=50\n",

-      "w_s=4*math.pi*f1/4\n",

-      "T_en=(3/w_s)*I_n**2*(r2/s_mn)    \n",

-      "print(\"Torque developed=%.2f Nm\" %T_en)\n",

-      "print(\"motor is operated with DOL starting\")\n",

-      "s_mn=r2/math.sqrt((r1)**2+((x1+x2)/2)**2)\n",

-      "I_d=V1/2/math.sqrt((r1+r2/s_mn)**2+((x1+x2)/2)**2)    \n",

-      "print(\"current=%.3f A\" %I_d)\n",

-      "pf=(r1+r2/s_mn)/math.sqrt((r1+r2/s_mn)**2+((x1+x2)/2)**2)    \n",

-      "print(\"\\npf=%.3f\" %pf)\n",

-      "f1=25\n",

-      "w_s=4*math.pi*f1/4\n",

-      "T_en=(3/w_s)*I_d**2*(r2/s_mn)  \n",

-      "\n",

-      "\n",

-      "#Results  \n",

-      "print(\"Torque developed=%.3f Nm\" %T_en)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "at starting in normal conditions\n",

-        "current=119.31 A\n",

-        "pf=0.2983\n",

-        "\n",

-        "Torque developed=108.75 Nm\n",

-        "motor is operated with DOL starting\n",

-        "current=106 A\n",

-        "pf=0.53\n",

-        "Torque developed=171.673 Nm\n",

-        "at max torque conditions\n",

-        "current=79.829 A\n",

-        "pf=0.7695\n",

-        "Torque developed=396.26 Nm\n",

-        "motor is operated with DOL starting\n",

-        "current=71.199 A\n",

-        "\n",

-        "pf=0.822\n",

-        "Torque developed=330.883 Nm\n"

-       ]

-      }

-     ],

-     "prompt_number": 21

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.25, Page No 709"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "x1=1.0\n",

-      "X_m=50.0\n",

-      "X_e=x1*X_m/(x1+X_m)\n",

-      "V=231.0\n",

-      "V_e=V*X_m/(x1+X_m)\n",

-      "x2=1.0\n",

-      "r2=.4\n",

-      "r1=0\n",

-      "\n",

-      "#Calculations\n",

-      "s_m=r2/(x2+X_e)    \n",

-      "print(\"slip at max torque=%.2f\" %s_m)\n",

-      "s_mT=r2/(x2+X_m)    \n",

-      "print(\"slip at max torque=%.5f\" %s_mT)\n",

-      "f1=50.0\n",

-      "w_s=4*math.pi*f1/4\n",

-      "print(\"for constant voltage input\")\n",

-      "T_est=(3/w_s)*(V_e/math.sqrt(r2**2+(x2+X_e)**2))**2*(r2)    \n",

-      "print(\"starting torque=%.3f Nm\" %T_est)\n",

-      "T_em=(3/w_s)*V_e**2/(2*(x2+X_e))    \n",

-      "print(\"maximum torque developed=%.2f Nm\" %T_em)\n",

-      "print(\"for constant current input\")\n",

-      "I1=28\n",

-      "T_est=(3/w_s)*(I1*X_m)**2/(r2**2+(x2+X_m)**2)*r2    \n",

-      "print(\"starting torque=%.3f Nm\" %T_est)\n",

-      "T_em=(3/w_s)*(I1*X_m)**2/(2*(x2+X_m))   \n",

-      "print(\"maximum torque developed=%.3f Nm\" %T_em)\n",

-      "s=s_mT\n",

-      "i=1\n",

-      "I_m=I1*(r2/s+i*x2)/(r2/s+i*(x2+X_m))\n",

-      "I_m=math.fabs(I_m)\n",

-      "V1=math.sqrt(3)*I_m*X_m    \n",

-      "\n",

-      "#Results\n",

-      "print(\"supply voltage reqd=%.1f V\" %V1)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "slip at max torque=0.20\n",

-        "slip at max torque=0.00784\n",

-        "for constant voltage input\n",

-        "starting torque=95.988 Nm\n",

-        "maximum torque developed=247.31 Nm\n",

-        "for constant current input\n",

-        "starting torque=5.756 Nm\n",

-        "maximum torque developed=366.993 Nm\n",

-        "supply voltage reqd=1236.2 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 22

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.27, Page No 718"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=420.0\n",

-      "V1=V/math.sqrt(3)\n",

-      "T_e=450.0\n",

-      "N=1440.0\n",

-      "n=1000.0\n",

-      "T_L=T_e*(n/N)**2\n",

-      "n1=1500.0\n",

-      "\n",

-      "#Calculations\n",

-      "w_s=2*math.pi*n1/60\n",

-      "w_m=2*math.pi*n/60\n",

-      "a=.8\n",

-      "I_d=T_L*w_s/(2.339*a*V1)\n",

-      "k=0\n",

-      "R=(1-w_m/w_s)*(2.339*a*V1)/(I_d*(1-k))    \n",

-      "print(\"value of chopper resistance=%.4f ohm\" %R)\n",

-      "n=1320.0\n",

-      "T_L=T_e*(n/N)**2\n",

-      "I_d=T_L*w_s/(2.339*a*V1)    \n",

-      "print(\"Inductor current=%.3f A\" %I_d)\n",

-      "w_m=2*math.pi*n/60\n",

-      "k=1-((1-w_m/w_s)*(2.339*a*V1)/(I_d*R))    \n",

-      "print(\"value of duty cycle=%.4f\" %k)\n",

-      "s=(n1-n)/n1\n",

-      "V_d=2.339*s*a*V1    \n",

-      "print(\"Rectifed o/p voltage=%.3f V\" %V_d)\n",

-      "P=V_d*I_d\n",

-      "I2=math.sqrt(2/3)*I_d\n",

-      "r2=0.02\n",

-      "Pr=3*I2**2*r2\n",

-      "I1=a*I2\n",

-      "r1=0.015\n",

-      "Ps=3*I1**2*r1\n",

-      "Po=T_L*w_m\n",

-      "Pi=Po+Ps+Pr+P\n",

-      "eff=Po/Pi*100   \n",

-      "\n",

-      "#Results\n",

-      "print(\"Efficiency(in percent)=%.2f\" %eff)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "value of chopper resistance=2.0132 ohm\n",

-        "Inductor current=130.902 A\n",

-        "value of duty cycle=0.7934\n",

-        "Rectifed o/p voltage=54.449 V\n",

-        "Efficiency(in percent)=88.00\n"

-       ]

-      }

-     ],

-     "prompt_number": 23

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.28, Page No 720"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=400.0\n",

-      "V_ph=V/math.sqrt(3)\n",

-      "N_s=1000.0\n",

-      "N=800.0\n",

-      "a=.7\n",

-      "I_d=110\n",

-      "R=2.0\n",

-      "\n",

-      "#Calculations\n",

-      "k=1-((1-N/N_s)*(2.339*a*V_ph)/(I_d*R))    \n",

-      "print(\"value of duty cycle=%.3f\" %k)\n",

-      "P=I_d**2*R*(1-k)\n",

-      "I1=a*I_d*math.sqrt(2/3)\n",

-      "r1=0.1\n",

-      "r2=0.08\n",

-      "Pr=3*I1**2*(r1+r2)\n",

-      "P_o=20000\n",

-      "P_i=P_o+Pr+P\n",

-      "eff=P_o/P_i*100    \n",

-      "print(\"Efficiency=%.2f\" %eff)\n",

-      "I11=math.sqrt(6)/math.pi*a*I_d\n",

-      "th=43\n",

-      "P_ip=math.sqrt(3)*V*I11*math.cos(math.radians(th))\n",

-      "pf=P_ip/(math.sqrt(3)*V*I11)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"Input power factor=%.4f\" %pf)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "value of duty cycle=0.656\n",

-        "Efficiency=70.62\n",

-        "Input power factor=0.7314\n"

-       ]

-      }

-     ],

-     "prompt_number": 24

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.29, Page No 724"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=420.0\n",

-      "V1=V/math.sqrt(3)\n",

-      "N=1000.0\n",

-      "w_m=2*math.pi*N/60\n",

-      "N_s=1500.0\n",

-      "\n",

-      "#Calculations\n",

-      "s=(N_s-N)/N_s\n",

-      "a=0.8\n",

-      "V_d=2.339*a*s*V1    \n",

-      "print(\"rectified voltage=%.2f V\" %V_d)\n",

-      "T=450.0\n",

-      "N1=1200.0\n",

-      "T_L=T*(N/N1)**2\n",

-      "f1=50\n",

-      "w_s=4*math.pi*f1/4\n",

-      "I_d=w_s*T_L/(2.339*a*V1)    \n",

-      "print(\"inductor current=%.2f A\" %I_d)\n",

-      "a_T=-.4\n",

-      "a1=math.degrees(math.acos(s*a/a_T))\n",

-      "print(\"delay angle of inverter=%.2f deg\" %a1)\n",

-      "\n",

-      "P_s=V_d*I_d\n",

-      "P_o=T_L*w_m\n",

-      "R_d=0.01\n",

-      "P_i=I_d**2*R_d\n",

-      "I2=math.sqrt(2/3)*I_d\n",

-      "r2=0.02\n",

-      "r1=0.015\n",

-      "P_rol=3*I2**2*r2\n",

-      "I1=a*I2\n",

-      "P_sol=3*I1**2*r1\n",

-      "P_i=P_o+P_rol+P_sol+P_i\n",

-      "eff=P_o/P_i*100    \n",

-      "print(\"\\nefficiency=%.2f\" %eff)\n",

-      "w_m=w_s*(1+(-a_T/a)*math.cos(math.radians(a1))-w_s*R_d*T_L/(2.339*a*V1)**2)\n",

-      "N=w_m*60/(2*math.pi) \n",

-      "\n",

-      "#Results   \n",

-      "print(\"motor speed=%.1f rpm\" %N)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rectified voltage=151.25 V\n",

-        "inductor current=108.18 A\n",

-        "delay angle of inverter=131.81 deg\n",

-        "\n",

-        "efficiency=99.64\n",

-        "motor speed=996.4 rpm\n"

-       ]

-      }

-     ],

-     "prompt_number": 25

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.30, Page No 726"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=700.0\n",

-      "E2=V/math.sqrt(3)\n",

-      "N_s=1500.0\n",

-      "N=1200.0\n",

-      "\n",

-      "#Calculations\n",

-      "s=(N_s-N)/N_s\n",

-      "V_dd=0.7\n",

-      "V_dt=1.5\n",

-      "V_d=3*math.sqrt(6)*s*E2/math.pi-2*V_dd\n",

-      "V1=415.0\n",

-      "a=math.degrees(math.acos((3*math.sqrt(2)*E2/math.pi)**-1*(-V_d+2*V_dt)))\n",

-      "\n",

-      "#Results\n",

-      "print(\"firing angle advance=%.2f deg\" %(180-a))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "firing angle advance=70.22 deg\n"

-       ]

-      }

-     ],

-     "prompt_number": 26

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.31, Page No 726"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=700.0\n",

-      "E2=V/math.sqrt(3)\n",

-      "N_s=1500.0\n",

-      "N=1200.0\n",

-      "\n",

-      "#Calculations\n",

-      "s=(N_s-N)/N_s\n",

-      "V_dd=.7\n",

-      "V_dt=1.5\n",

-      "a=0\n",

-      "u=18 #overlap angle in case of rectifier\n",

-      "V_d=3*math.sqrt(6)*s*E2*(math.cos(math.radians(a))+math.cos(math.radians(a+u)))/(2*math.pi)-2*V_dd\n",

-      "V1=415\n",

-      "V_ml=math.sqrt(2)*V1\n",

-      "u=4 #overlap anglein the inverter\n",

-      " #V_dc=-(3*V_ml*(math.cos(math.radians(a))+math.cos(math.radians(a+u)))/(2*math.pi)-2*V_dt)\n",

-      " #V_dc=V_d\n",

-      " #after solving %  (1+math.cos(math.radians(u)))*math.cos(math.radians(a))-math.sin(math.radians(u))*math.sin(math.radians(a))=-.6425\n",

-      "a=math.degrees(math.acos(-.6425/(math.sqrt((1+math.cos(math.radians(u)))**2+math.sin(math.radians(u))**2))))-math.degrees(math.asin(math.sin(math.radians(a))/(1+math.cos(math.radians(u)))))\n",

-      "\n",

-      "#Results\n",

-      "print(\"firing angle advance=%.2f deg\" %(180-a))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "firing angle advance=71.25 deg\n"

-       ]

-      }

-     ],

-     "prompt_number": 27

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.32, Page No 727"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=700.0\n",

-      "E2=V\n",

-      "N_s=1500.0\n",

-      "N=1200.0\n",

-      "\n",

-      "#Calculations\n",

-      "s=(N_s-N)/N_s\n",

-      "V1=415.0\n",

-      "a_T=s*E2/V1    \n",

-      "\n",

-      "#Results\n",

-      "print(\"voltage ratio of the transformer=%.2f\" %a_T)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "voltage ratio of the transformer=0.34\n"

-       ]

-      }

-     ],

-     "prompt_number": 28

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.33, Page No 733"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "P=6.0\n",

-      "N_s=600.0\n",

-      "f1=P*N_s/120.0\n",

-      "V=400.0\n",

-      "f=50.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_t=f1*V/f    \n",

-      "print(\"supply freq=%.0f Hz\" %V_t)\n",

-      "T=340.0\n",

-      "N=1000.0\n",

-      "T_L=T*(N_s/N)**2\n",

-      "w_s=2*math.pi*N_s/60\n",

-      "P=T_L*w_s\n",

-      "I_a=P/(math.sqrt(3)*V_t)    \n",

-      "print(\"armature current=%.2f A\" %I_a)\n",

-      "Z_s=2\n",

-      "X_s=f1/f*math.fabs(Z_s)\n",

-      "V_t=V_t/math.sqrt(3)\n",

-      "Ef=math.sqrt(V_t**2+(I_a*X_s)**2)\n",

-      "print(\"excitation voltage=%.2f V\" %(math.sqrt(3)*Ef))\n",

-      "dl=math.degrees(math.atan(I_a*X_s/V_t))\n",

-      "print(\"load angle=%.2f deg\" %dl)\n",

-      "T_em=(3/w_s)*(Ef*V_t/X_s)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"pull out torque=%.2f Nm\" %T_em)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "supply freq=240 Hz\n",

-        "armature current=18.50 A\n",

-        "excitation voltage=243.06 V\n",

-        "load angle=9.10 deg\n",

-        "pull out torque=773.69 Nm\n"

-       ]

-      }

-     ],

-     "prompt_number": 29

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.34, Page No 736"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "P=4.0\n",

-      "f=50.0\n",

-      "w_s=4*math.pi*f/P\n",

-      "X_d=8.0\n",

-      "X_q=2.0\n",

-      "T_e=80.0\n",

-      "V=400.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_t=V/math.sqrt(3)\n",

-      "dl=(1/2)*math.degrees(math.asin(T_e*w_s/((3/2)*(V_t)**2*(1/X_q-1/X_d))))    \n",

-      "print(\"load angle=%.3f deg\" %dl)\n",

-      "I_d=V_t*math.cos(math.radians(dl))/X_d\n",

-      "I_q=V_t*math.sin(math.radians(dl))/X_q\n",

-      "I_a=math.sqrt(I_d**2+I_q**2)    \n",

-      "print(\"armature current=%.2f A\" %I_a)\n",

-      "pf=T_e*w_s/(math.sqrt(3)*V*I_a)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"input power factor=%.4f\" %pf)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "load angle=0.000 deg\n",

-        "armature current=28.87 A\n",

-        "input power factor=0.6283\n"

-       ]

-      }

-     ],

-     "prompt_number": 30

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.35, Page No 737"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "T_e=3.0\n",

-      "K_m=1.2\n",

-      "I_a=T_e/K_m\n",

-      "r_a=2.0\n",

-      "V=230.0\n",

-      "\n",

-      "#Calculations\n",

-      "E_a=(0.263*math.sqrt(2)*V-I_a*r_a)/(1-55/180)\n",

-      "w_m=E_a/K_m\n",

-      "N=w_m*60/(2*math.pi)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"motor speed=%.2f rpm\" %N)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "motor speed=640.96 rpm\n"

-       ]

-      }

-     ],

-     "prompt_number": 31

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.36, Page No 738"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "K_m=1.0\n",

-      "N=1360.0\n",

-      "\n",

-      "#Calculations\n",

-      "w_m=2*math.pi*N/60\n",

-      "E_a=K_m*w_m\n",

-      " #after calculations V_t % calculated\n",

-      "V_t=163.45\n",

-      "r_a=4\n",

-      "I_a=(V_t-E_a)/r_a\n",

-      "T_e=K_m*I_a    \n",

-      "\n",

-      "#Results\n",

-      "print(\"motor torque=%.4f Nm\" %T_e)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "motor torque=5.2578 Nm\n"

-       ]

-      }

-     ],

-     "prompt_number": 32

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.37, Page No 740"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "K_m=1.0\n",

-      "N=2100.0\n",

-      "\n",

-      "#Calculations\n",

-      "w_m=2*math.pi*N/60\n",

-      "E_a=K_m*w_m\n",

-      " #after calculations V_t % calculated\n",

-      "V_t=227.66\n",

-      "r_a=4\n",

-      "I_a=(V_t-E_a)/r_a\n",

-      "T_e=K_m*I_a    \n",

-      "\n",

-      "#Results\n",

-      "print(\"motor torque=%.2f Nm\" %T_e)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "motor torque=1.94 Nm\n"

-       ]

-      }

-     ],

-     "prompt_number": 33

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.38, Page No 742"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "K_m=1.0\n",

-      "N=840.0\n",

-      "\n",

-      "#Calculations\n",

-      "w_m=2*math.pi*N/60\n",

-      "E_a=K_m*w_m\n",

-      "V=230.0\n",

-      "a=75.0\n",

-      "V_t=math.sqrt(2)*V/math.pi*(1+math.cos(math.radians(a)))\n",

-      "r_a=4\n",

-      "I_a=(V_t-E_a)/r_a\n",

-      "T_e=K_m*I_a    \n",

-      "\n",

-      "#Results\n",

-      "print(\"motor torque=%.4f Nm\" %T_e)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits.\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "motor torque=10.5922 Nm\n"

-       ]

-      }

-     ],

-     "prompt_number": 34

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.39, Page No 743"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "K_m=1.0\n",

-      "N=1400.0\n",

-      "\n",

-      "#Calculations\n",

-      "w_m=2*math.pi*N/60\n",

-      "E_a=K_m*w_m\n",

-      "V=230.0\n",

-      "a=60.0\n",

-      "a1=212\n",

-      "V_t=math.sqrt(2)*V/math.pi*(math.cos(math.radians(a))-math.cos(math.radians(a1)))+E_a*(180+a-a1)/180\n",

-      "r_a=3\n",

-      "I_a=(V_t-E_a)/r_a\n",

-      "T_e=K_m*I_a   \n",

-      "\n",

-      "#Results\n",

-      "print(\"motor torque=%.3f Nm\" %T_e)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "motor torque=5.257 Nm\n"

-       ]

-      }

-     ],

-     "prompt_number": 35

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.40, Page No 745"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "K_m=1.0\n",

-      "N=600.0\n",

-      "w_m=2*math.pi*N/60\n",

-      "E_a=K_m*w_m\n",

-      "V=230.0\n",

-      "a=60.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_t=2*math.sqrt(2)*V/math.pi*(math.cos(math.radians(a)))\n",

-      "r_a=3\n",

-      "I_a=(V_t-E_a)/r_a\n",

-      "T_e=K_m*I_a    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"motor torque=%.3f Nm\" %T_e)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "motor torque=13.568 Nm\n"

-       ]

-      }

-     ],

-     "prompt_number": 36

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.41, Page No 745"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "r1=.6\n",

-      "r2=.4\n",

-      "s=0.04\n",

-      "x1=1.6\n",

-      "x2=1.6\n",

-      "Z=(r1+r2/s)+(x1+x2)\n",

-      "V=400.0\n",

-      "I1=V/Z    \n",

-      "print(\"source current=%.3f A \" %math.degrees(math.atan(I1.imag/I1.real)))\n",

-      "print(\"and with %.1f deg phase\" %math.fabs(I1))\n",

-      "I2=V/Z\n",

-      "N=1500\n",

-      "w_s=2*math.pi*N/60\n",

-      "T_e=(3/w_s)*abs(I2)**2*r2/s    \n",

-      "print(\"motor torque=%.2f Nm\" %T_e)\n",

-      "N_r=N*(1-s)\n",

-      "\n",

-      "f=45\n",

-      "N_s1=120*f/4\n",

-      "w_s=2*math.pi*N_s1/60\n",

-      "s1=(N_s1-N_r)/N_s1\n",

-      "Z=(r1+r2/s1)+(x1+x2)*f/50.0\n",

-      "V=360\n",

-      "I1=V/Z    \n",

-      "print(\"source current=%.3f A \" %math.degrees(math.atan(I1.imag/I1.real)))\n",

-      "print(\"and with %.1f deg phase\" %math.fabs(I1))\n",

-      "I2=V/Z\n",

-      "T_e=(3/w_s)*abs(I2)**2*r2/s1    \n",

-      "print(\"motor torque=%.2f Nm\" %T_e)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "source current=0.000 A \n",

-        "and with 29.0 deg phase\n",

-        "motor torque=160.46 Nm\n",

-        "source current=-0.000 A \n",

-        "and with 142.9 deg phase\n",

-        "motor torque=-2598.45 Nm\n"

-       ]

-      }

-     ],

-     "prompt_number": 37

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Power_Electronics/Chapter12_1.ipynb b/_Power_Electronics/Chapter12_1.ipynb
deleted file mode 100755
index f8605d69..00000000
--- a/_Power_Electronics/Chapter12_1.ipynb
+++ /dev/null
@@ -1,1997 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 12 : Electic Drives"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.1, Page No 658"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "T_e=15.0 #Nm\n",

-      "K_m=0.5 #V-s/rad\n",

-      "I_a=T_e/K_m\n",

-      "n_m=1000.0\n",

-      "\n",

-      "#Calculations\n",

-      "w_m=2*math.pi*n_m/60\n",

-      "E_a=K_m*w_m\n",

-      "r_a=0.7\n",

-      "V_t=E_a+I_a*r_a\n",

-      "V_s=230.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "a=math.degrees(math.acos(2*math.pi*V_t/V_m-1))\n",

-      "print(\"firing angle delay=%.3f deg\" %a)\n",

-      "I_Tr=I_a*math.sqrt((180-a)/360)    \n",

-      "print(\"rms value of thyristor current=%.3f A\" %I_Tr)\n",

-      "I_fdr=I_a*math.sqrt((180+a)/360)    \n",

-      "print(\"rms value of freewheeling diode current=%.3f A\" %I_fdr)\n",

-      "pf=V_t*I_a/(V_s*I_Tr)  \n",

-      "\n",

-      "#Results  \n",

-      "print(\"input power factor=%.4f\" %pf)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "firing angle delay=65.349 deg\n",

-        "rms value of thyristor current=16.930 A\n",

-        "rms value of freewheeling diode current=24.766 A\n",

-        "input power factor=0.5652\n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.2, Page No 660"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=230.0\n",

-      "E=150.0\n",

-      "R=8.0\n",

-      "\n",

-      "#Calculations\n",

-      "th1=math.sin(math.radians(E/(math.sqrt(2)*V)))\n",

-      "I_o=(1/(2*math.pi*R))*(2*math.sqrt(2)*230*math.cos(math.radians(th1))-E*(math.pi-2*th1*math.pi/180))    \n",

-      "P=E*I_o    \n",

-      "I_or=math.sqrt((1/(2*math.pi*R**2))*((V**2+E**2)*(math.pi-2*th1*math.pi/180)+V**2*math.sin(math.radians(2*th1))-4*math.sqrt(2)*V*E*math.cos(math.radians(th1))))\n",

-      "P_r=I_or**2*R    \n",

-      "pf=(P+P_r)/(V*I_or)\n",

-      "\n",

-      "#Results\n",

-      "print(\"avg charging curent=%.4f A\" %I_o)\n",

-      "print(\"power supplied to the battery=%.2f W\" %P)\n",

-      "print(\"power dissipated by the resistor=%.3f W\" %P_r)    \n",

-      "print(\"supply pf=%.3f\" %pf)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "avg charging curent=3.5679 A\n",

-        "power supplied to the battery=535.18 W\n",

-        "power dissipated by the resistor=829.760 W\n",

-        "supply pf=0.583\n"

-       ]

-      }

-     ],

-     "prompt_number": 2

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.3 Page No 661"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variablesV_s=250\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "a=30.0\n",

-      "k=0.03 #Nm/A**2\n",

-      "n_m=1000.0\n",

-      "\n",

-      "#Calculations\n",

-      "w_m=2*math.pi*n_m/60\n",

-      "r=.2 #r_a+r_s\n",

-      "V_t=V_m/math.pi*(1+math.cos(math.radians(a)))\n",

-      "I_a=V_t/(k*w_m+r)   \n",

-      "print(\"motor armature current=%.2f A\" %I_a)\n",

-      "T_e=k*I_a**2    \n",

-      "print(\"motor torque=%.3f Nm\" %T_e)\n",

-      "I_sr=I_a*math.sqrt((180-a)/180)\n",

-      "pf=(V_t*I_a)/(V_s*I_sr)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"input power factor=%.2f\" %pf)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "motor armature current=57.82 A\n",

-        "motor torque=100.285 Nm\n",

-        "input power factor=0.92\n"

-       ]

-      }

-     ],

-     "prompt_number": 3

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.4, Page No 663"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=400.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "V_f=2*V_m/math.pi\n",

-      "r_f=200.0\n",

-      "I_f=V_f/r_f\n",

-      "T_e=85.0\n",

-      "K_a=0.8\n",

-      "\n",

-      "#Calculations\n",

-      "I_a=T_e/(I_f*K_a)    \n",

-      "print(\"rated armature current=%.2f A\" %I_a)\n",

-      "n_m=1200.0\n",

-      "w_m=2*math.pi*n_m/60\n",

-      "r_a=0.2\n",

-      "V_t=K_a*I_f*w_m+I_a*r_a\n",

-      "a=math.degrees(math.acos(V_t*math.pi/(2*V_m)))\n",

-      "print(\"firing angle delay=%.2f deg\" %a)\n",

-      "E_a=V_t\n",

-      "w_mo=E_a/(K_a*I_f)\n",

-      "N=60*w_mo/(2*math.pi)\n",

-      "reg=((N-n_m)/n_m)*100    \n",

-      "print(\"speed regulation at full load=%.2f\" %reg)\n",

-      "I_ar=I_a\n",

-      "pf=(V_t*I_a)/(V_s*I_ar)    \n",

-      "print(\"input power factor of armature convertor=%.4f\" %pf)\n",

-      "I_fr=I_f\n",

-      "I_sr=math.sqrt(I_fr**2+I_ar**2)\n",

-      "VA=I_sr*V_s\n",

-      "P=V_t*I_a+V_f*I_f\n",

-      "\n",

-      "#Results\n",

-      "print(\"input power factor of drive=%.4f\" %(P/VA))\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rated armature current=59.01 A\n",

-        "firing angle delay=57.63 deg\n",

-        "speed regulation at full load=6.52\n",

-        "input power factor of armature convertor=0.4821\n",

-        "input power factor of drive=0.5093\n"

-       ]

-      }

-     ],

-     "prompt_number": 4

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.5 Page No 664"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=400.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "V_f=2*V_m/math.pi\n",

-      "\n",

-      "#Calculations\n",

-      "a1=math.degrees(math.acos(V_t*math.pi/(2*V_m))) \n",

-      "print(\"delay angle of field converter=%.0f deg\" %a1)\n",

-      "r_f=200.0\n",

-      "I_f=V_f/r_f\n",

-      "T_e=85.0\n",

-      "K_a=0.8\n",

-      "I_a=T_e/(I_f*K_a)\n",

-      "n_m=1200.0\n",

-      "w_m=2*math.pi*n_m/60\n",

-      "r_a=0.1\n",

-      "I_a=50.0\n",

-      "V_t=-K_a*I_f*w_m+I_a*r_a\n",

-      "a=math.degrees(math.acos(V_t*math.pi/(2*V_m)))\n",

-      "\n",

-      "#Results\n",

-      "print(\"firing angle delay of armature converter=%.3f deg\" %a)\n",

-      "print(\"power fed back to ac supply=%.0f W\" %(-V_t*I_a))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "delay angle of field converter=58 deg\n",

-        "firing angle delay of armature converter=119.260 deg\n",

-        "power fed back to ac supply=8801 W\n"

-       ]

-      }

-     ],

-     "prompt_number": 5

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.6 Page No 665"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_t=220.0\n",

-      "n_m=1500.0\n",

-      "w_m=2*math.pi*n_m/60\n",

-      "I_a=10.0\n",

-      "r_a=1.0\n",

-      "\n",

-      "#Calculations\n",

-      "K_m=(V_t-I_a*r_a)/(w_m)\n",

-      "T=5.0\n",

-      "I_a=T/K_m\n",

-      "V_s=230.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "a=30.0\n",

-      "V_t=2*V_m*math.cos(math.radians(a))/math.pi\n",

-      "w_m=(V_t-I_a*r_a)/K_m\n",

-      "N=w_m*60/(2*math.pi)    \n",

-      "\n",

-      "print(\"motor speed=%.2f rpm\" %N)\n",

-      "a=45\n",

-      "n_m=1000\n",

-      "w_m=2*math.pi*n_m/60\n",

-      "V_t=2*V_m*math.cos(math.radians(a))/math.pi\n",

-      "I_a=(V_t-K_m*w_m)/r_a\n",

-      "T_e=K_m*I_a    \n",

-      "\n",

-      "#Results\n",

-      "print(\"torque developed=%.3f Nm\" %T_e)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "motor speed=1254.22 rpm\n",

-        "torque developed=8.586 Nm\n"

-       ]

-      }

-     ],

-     "prompt_number": 6

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.7, Page No 666"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_t=220.0\n",

-      "n_m=1000.0\n",

-      "w_m=2*math.pi*n_m/60\n",

-      "I_a=60.0\n",

-      "r_a=.1\n",

-      "\n",

-      "#Calculations\n",

-      "K_m=(V_t-I_a*r_a)/(w_m)\n",

-      "V_s=230\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "print(\"for 600rpm speed\")\n",

-      "n_m=600.0\n",

-      "w_m=2*math.pi*n_m/60\n",

-      "a=math.degrees(math.acos((K_m*w_m+I_a*r_a)*math.pi/(2*V_m))) \n",

-      "print(\"firing angle=%.3f deg\" %a)\n",

-      "print(\"for -500rpm speed\")\n",

-      "n_m=-500.0\n",

-      "w_m=2*math.pi*n_m/60\n",

-      "a=math.degrees(math.acos((K_m*w_m+I_a*r_a)*math.pi/(2*V_m)))\n",

-      "print(\"firing angle=%.2f deg\" %a)\n",

-      "I_a=I_a/2\n",

-      "a=150\n",

-      "V_t=2*V_m*math.cos(math.radians(a))/math.pi\n",

-      "w_m=(V_t-I_a*r_a)/K_m\n",

-      "N=w_m*60/(2*math.pi)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"motor speed=%.3f rpm\" %N)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for 600rpm speed\n",

-        "firing angle=49.530 deg\n",

-        "for -500rpm speed\n",

-        "firing angle=119.19 deg\n",

-        "motor speed=-852.011 rpm\n"

-       ]

-      }

-     ],

-     "prompt_number": 7

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.8 Page No 672"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "K_m=1.5\n",

-      "T_e=50.0\n",

-      "I_a=T_e/K_m\n",

-      "r_a=0.9\n",

-      "a=45.0\n",

-      "V_s=415.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_ml=math.sqrt(2)*V_s\n",

-      "w_m=((3*V_ml*(1+math.cos(math.radians(a)))/(2*math.pi))-I_a*r_a)/K_m\n",

-      "N=w_m*60/(2*math.pi)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"motor speed=%.2f rpm\" %N)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "motor speed=2854.42 rpm\n"

-       ]

-      }

-     ],

-     "prompt_number": 8

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.9 Page No 672"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variablesV_t=600\n",

-      "n_m=1500.0\n",

-      "w_m=2*math.pi*n_m/60\n",

-      "I_a=80.0\n",

-      "r_a=1.0\n",

-      "\n",

-      "#Calculations\n",

-      "K_m=(V_t-I_a*r_a)/(w_m)\n",

-      "V_s=400.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "print(\"for firing angle=45deg and speed=1200rpm\")\n",

-      "a=45.0\n",

-      "n_m=1200.0\n",

-      "w_m=2*math.pi*n_m/60\n",

-      "I_a=(3*V_m*(1+math.cos(math.radians(a)))/(2*math.pi)-K_m*w_m)/r_a\n",

-      "I_sr=I_a*math.sqrt(2/3)    \n",

-      "print(\"rms value of source current=%.3f A\" %I_sr)\n",

-      "print(\"rms value of thyristor current=%.3f A\" %(I_a*math.sqrt(1/3)))\n",

-      "print(\"avg value of thyristor current=%.2f A\" %I_a*(1/3))\n",

-      "pf=(3/(2*math.pi)*(1+math.cos(math.radians(a))))    \n",

-      "print(\"input power factor=%.3f\" %pf)\n",

-      "\n",

-      "print(\"for firing angle=90deg and speed=700rpm\")\n",

-      "a=90\n",

-      "n_m=700\n",

-      "w_m=2*math.pi*n_m/60\n",

-      "I_a=(3*V_m*(1+math.cos(math.radians(a)))/(2*math.pi)-K_m*w_m)/r_a\n",

-      "I_sr=I_a*math.sqrt(90/180)    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"rms value of source current=%.3f A\" %I_sr)\n",

-      "print(\"rms value of thyristor current=%.3f A\" %(I_a*math.sqrt(90.0/360)))\n",

-      "print(\"avg value of thyristor current=%.3f A\" %I_a*(1/3))\n",

-      "pf=(math.sqrt(6)/(2*math.pi)*(1+math.cos(math.radians(a))))*math.sqrt(180/(180-a))    \n",

-      "print(\"input power factor=%.4f\" %pf)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for firing angle=45deg and speed=1200rpm\n",

-        "rms value of source current=0.000 A\n",

-        "rms value of thyristor current=0.000 A\n",

-        "\n",

-        "input power factor=0.815\n",

-        "for firing angle=90deg and speed=700rpm\n",

-        "rms value of source current=0.000 A\n",

-        "rms value of thyristor current=195.558 A\n",

-        "\n",

-        "input power factor=0.5513\n"

-       ]

-      }

-     ],

-     "prompt_number": 9

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.10 Page No 676"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=400.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "a=30\n",

-      "V_t=3*V_m*math.cos(math.radians(a))/math.pi\n",

-      "I_a=21.0\n",

-      "r_a=.1\n",

-      "V_d=2.0\n",

-      "K_m=1.6\n",

-      "\n",

-      "#Calculations\n",

-      "w_m=(V_t-I_a*r_a-V_d)/K_m\n",

-      "N=w_m*60/(2*math.pi)    \n",

-      "print(\"speed of motor=%.1f rpm\" %N)\n",

-      "\n",

-      "N=2000\n",

-      "w_m=2*math.pi*N/60\n",

-      "I_a=210\n",

-      "V_t=K_m*w_m+I_a*r_a+V_d\n",

-      "a=math.degrees(math.acos(V_t*math.pi/(3*V_m)))\n",

-      "print(\"firing angle=%.2f deg\" %a)\n",

-      "I_sr=I_a*math.sqrt(2.0/3.0)\n",

-      "pf=V_t*I_a/(math.sqrt(3)*V_s*I_sr)    \n",

-      "print(\"supply power factor=%.3f\" %pf)\n",

-      "\n",

-      "I_a=21\n",

-      "w_m=(V_t-I_a*r_a-V_d)/K_m\n",

-      "n=w_m*60/(2*math.pi)\n",

-      "reg=(n-N)/N*100    \n",

-      "\n",

-      "#Results\n",

-      "print(\"speed regulation(percent)=%.2f\" %reg)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "speed of motor=2767.6 rpm\n",

-        "firing angle=48.48 deg\n",

-        "supply power factor=0.633\n",

-        "speed regulation(percent)=5.64\n"

-       ]

-      }

-     ],

-     "prompt_number": 10

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.11, Page No 677"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_t=230.0\n",

-      "V_l=V_t*math.pi/(3*math.sqrt(2))\n",

-      "V_ph=V_l/math.sqrt(3)\n",

-      "V_in=400     #per phase voltage input\n",

-      "\n",

-      "#Calculations\n",

-      "N1=1500.0\n",

-      "I_a1=20.0\n",

-      "r_a1=.6\n",

-      "E_a1=V_t-I_a1*r_a1\n",

-      "n1=1000.0\n",

-      "E_a2=E_a1/1500.0*1000.0\n",

-      "V_t1=E_a1+I_a1*r_a1\n",

-      "a1=math.degrees(math.acos(V_t1*math.pi/(3*math.sqrt(2.0)*V_l)))\n",

-      "I_a2=.5*I_a1\n",

-      "n2=-900.0\n",

-      "V_t2=n2*E_a2/N1+I_a2*r_a1\n",

-      "a2=math.degrees(math.acos(V_t2*math.pi/(3*math.sqrt(2)*V_l))) \n",

-      "\n",

-      "#Results\n",

-      "print(\"transformer phase turns ratio=%.3f\" %(V_in/V_ph))\n",

-      "print(\"for motor running at 1000rpm at rated torque\")\n",

-      "print(\"firing angle delay=%.2f deg\" %a1)\n",

-      "print(\"for motor running at -900rpm at half of rated torque\")\n",

-      "print(\"firing angle delay=%.3f deg\" %a2)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "transformer phase turns ratio=4.068\n",

-        "for motor running at 1000rpm at rated torque\n",

-        "firing angle delay=0.00 deg\n",

-        "for motor running at -900rpm at half of rated torque\n",

-        "firing angle delay=110.674 deg\n"

-       ]

-      }

-     ],

-     "prompt_number": 11

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.12, Page No 678"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variablesV_s=400\n",

-      "V_ml=math.sqrt(2)*V_s\n",

-      "V_f=3*V_ml/math.pi\n",

-      "R_f=300.0\n",

-      "I_f=V_f/R_f\n",

-      "T_e=60.0\n",

-      "k=1.1\n",

-      "\n",

-      "#Calculations\n",

-      "I_a=T_e/(k*I_f)\n",

-      "N1=1000.0\n",

-      "w_m1=2*math.pi*N1/60\n",

-      "r_a1=.3\n",

-      "V_t1=k*I_f*w_m1+I_a*r_a1\n",

-      "a1=math.degrees(math.acos(V_f*math.pi/(3*V_ml)))\n",

-      "N2=3000\n",

-      "w_m2=2*math.pi*N/60\n",

-      "a2=0\n",

-      "V_t2=3*V_ml*math.cos(math.radians(a))/math.pi\n",

-      "I_f2=(V_t2-I_a*r_a)/(w_m2*k)\n",

-      "V_f2=I_f2*R_f\n",

-      "a2=math.degrees(math.acos(V_f2*math.pi/(3*V_ml)))\n",

-      "\n",

-      "#Results\n",

-      "print(\"firing angle=%.3f deg\" %a)\n",

-      "print(\"firing angle=%.3f deg\" %a)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "firing angle=48.477 deg\n",

-        "firing angle=48.477 deg\n"

-       ]

-      }

-     ],

-     "prompt_number": 12

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.13, Page No 679"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      " #after calculating\n",

-      " #t=w_m/6000-math.pi/360\n",

-      "\n",

-      "N=1000.0\n",

-      "\n",

-      "#Calculations\n",

-      "w_m=2*math.pi*N/60\n",

-      "t=w_m/6000-math.pi/360    \n",

-      "\n",

-      "#Results\n",

-      "print(\"time reqd=%.2f s\" %t)\n",

-      " #printing mistake in the answer in book"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "time reqd=0.01 s\n"

-       ]

-      }

-     ],

-     "prompt_number": 13

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.14, Page No 679"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "I_a=1.0 #supposition\n",

-      "a=60.0\n",

-      "\n",

-      "#Calculations\n",

-      "I_s1=2*math.sqrt(2)/math.pi*I_a*math.sin(math.radians(a))\n",

-      "I_s3=2*math.sqrt(2)/(3*math.pi)*I_a*math.sin(math.radians(3*a))\n",

-      "I_s5=2*math.sqrt(2)/(5*math.pi)*I_a*math.sin(math.radians(5*a))\n",

-      "per3=I_s3/I_s1*100    \n",

-      "print(\"percent of 3rd harmonic current in fundamental=%.2f\" %per3)\n",

-      "per5=I_s5/I_s1*100    \n",

-      "\n",

-      "#Results\n",

-      "print(\"percent of 5th harmonic current in fundamental=%.2f\" %per5)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "percent of 3rd harmonic current in fundamental=0.00\n",

-        "percent of 5th harmonic current in fundamental=-20.00\n"

-       ]

-      }

-     ],

-     "prompt_number": 14

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.15, Page No 680"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "I_a=60.0\n",

-      "I_TA=I_a/3    \n",

-      "\n",

-      "#Calculations\n",

-      "print(\"avg thyristor current=%.0f A\" %I_TA)\n",

-      "I_Tr=I_a/math.sqrt(3)    \n",

-      "print(\"rms thyristor current=%.3f A\" %I_Tr)\n",

-      "V_s=400\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "I_sr=I_a*math.sqrt(2.0/3)\n",

-      "a=150\n",

-      "V_t=3*V_m*math.cos(math.radians(a))/math.pi\n",

-      "pf=V_t*I_a/(math.sqrt(3)*V_s*I_sr)    \n",

-      "print(\"power factor of ac source=%.3f\" %pf)\n",

-      "\n",

-      "r_a=0.5\n",

-      "K_m=2.4\n",

-      "w_m=(V_t-I_a*r_a)/K_m\n",

-      "N=w_m*60/(2*math.pi)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"Speed of motor=%.2f rpm\" %N)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "avg thyristor current=20 A\n",

-        "rms thyristor current=34.641 A\n",

-        "power factor of ac source=-0.827\n",

-        "Speed of motor=-1980.76 rpm\n"

-       ]

-      }

-     ],

-     "prompt_number": 15

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.16, Page No 685"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "I_a=300.0\n",

-      "V_s=600.0\n",

-      "a=0.6\n",

-      "V_t=a*V_s\n",

-      "P=V_t*I_a    \n",

-      "\n",

-      "#Calculations\n",

-      "print(\"input power from source=%.0f kW\" %(P/1000))\n",

-      "R_eq=V_s/(a*I_a)    \n",

-      "print(\"equivalent input resistance=%.3f ohm\" %R_eq)\n",

-      "k=.004\n",

-      "R=.04+.06\n",

-      "w_m=(a*V_s-I_a*R)/(k*I_a)\n",

-      "N=w_m*60/(2*math.pi)    \n",

-      "print(\"motor speed=%.1f rpm\" %N)\n",

-      "T_e=k*I_a**2    \n",

-      "\n",

-      "#Results\n",

-      "print(\"motor torque=%.0f Nm\" %T_e)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "input power from source=108 kW\n",

-        "equivalent input resistance=3.333 ohm\n",

-        "motor speed=2626.1 rpm\n",

-        "motor torque=360 Nm\n"

-       ]

-      }

-     ],

-     "prompt_number": 16

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.17, Page No 686"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "T_on=10.0\n",

-      "T_off=15.0\n",

-      "\n",

-      "#Calculations\n",

-      "a=T_on/(T_on+T_off)\n",

-      "V_s=230.0\n",

-      "V_t=a*V_s\n",

-      "r_a=3\n",

-      "K_m=.5\n",

-      "N=1500\n",

-      "w_m=2*math.pi*N/60\n",

-      "I_a=(V_t-K_m*w_m)/r_a    \n",

-      "\n",

-      "#Results\n",

-      "print(\"motor load current=%.3f A\" %I_a)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "motor load current=4.487 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 17

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.18, Page No 686"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "w_m=0    \n",

-      "print(\"lower limit of speed control=%.0f rpm\" %w_m)\n",

-      "I_a=25.0\n",

-      "r_a=.2\n",

-      "V_s=220\n",

-      "K_m=0.08\n",

-      "\n",

-      "#Calculations\n",

-      "a=(K_m*w_m+I_a*r_a)/V_s    \n",

-      "print(\"lower limit of duty cycle=%.3f\" %a)\n",

-      "a=1    \n",

-      "print(\"upper limit of duty cycle=%.0f\" %a)\n",

-      "w_m=(a*V_s-I_a*r_a)/K_m    \n",

-      "\n",

-      "#Results\n",

-      "print(\"upper limit of speed control=%.1f rpm\" %w_m)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "lower limit of speed control=0 rpm\n",

-        "lower limit of duty cycle=0.023\n",

-        "upper limit of duty cycle=1\n",

-        "upper limit of speed control=2687.5 rpm\n"

-       ]

-      }

-     ],

-     "prompt_number": 18

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.21, Page No 691"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "a=0.6\n",

-      "V_s=400.0\n",

-      "V_t=(1-a)*V_s\n",

-      "I_a=300.0\n",

-      "P=V_t*I_a  \n",

-      "\n",

-      "#Calculations  \n",

-      "print(\"power returned=%.0f kW\" %(P/1000))\n",

-      "r_a=.2\n",

-      "K_m=1.2\n",

-      "R_eq=(1-a)*V_s/I_a+r_a    \n",

-      "print(\"equivalent load resistance=%.4f ohm\" %R_eq)\n",

-      "w_mn=I_a*r_a/K_m\n",

-      "N=w_mn*60/(2*math.pi)    \n",

-      "print(\"min braking speed=%.2f rpm\" %N)\n",

-      "w_mx=(V_s+I_a*r_a)/K_m\n",

-      "N=w_mx*60/(2*math.pi)    \n",

-      "print(\"max braking speed=%.1f rpm\" %N)\n",

-      "w_m=(V_t+I_a*r_a)/K_m\n",

-      "N=w_m*60/(2*math.pi)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"max braking speed=%.1f rpm\" %N)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "power returned=48 kW\n",

-        "equivalent load resistance=0.7333 ohm\n",

-        "min braking speed=477.46 rpm\n",

-        "max braking speed=3660.6 rpm\n",

-        "max braking speed=1750.7 rpm\n"

-       ]

-      }

-     ],

-     "prompt_number": 19

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.22, Page No 699"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "N=1500.0\n",

-      "\n",

-      "#Calculations\n",

-      "print(\"when speed=1455rpm\")\n",

-      "n=1455.0\n",

-      "s1=(N-n)/N\n",

-      "r=math.sqrt(1/3)*(2/3)/(math.sqrt(s1)*(1-s1))    \n",

-      "print(\"I_2mx/I_2r=%.3f\" %r)\n",

-      "print(\"when speed=1350rpm\")\n",

-      "n=1350\n",

-      "s1=(N-n)/N\n",

-      "r=math.sqrt(1/3)*(2/3)/(math.sqrt(s1)*(1-s1))    \n",

-      "\n",

-      "#Results\n",

-      "print(\"I_2mx/I_2r=%.3f\" %r)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "when speed=1455rpm\n",

-        "I_2mx/I_2r=0.000\n",

-        "when speed=1350rpm\n",

-        "I_2mx/I_2r=0.000\n"

-       ]

-      }

-     ],

-     "prompt_number": 20

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.24, Page No 705"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V1=400.0\n",

-      "r1=0.6\n",

-      "r2=0.4\n",

-      "s=1.0\n",

-      "x1=1.6\n",

-      "x2=1.6\n",

-      "\n",

-      "#Calculations\n",

-      "print(\"at starting in normal conditions\")\n",

-      "I_n=V1/math.sqrt((r1+r2/s)**2+(x1+x2)**2)    \n",

-      "print(\"current=%.2f A\" %I_n)\n",

-      "pf=(r1+r2)/math.sqrt((r1+r2/s)**2+(x1+x2)**2)    \n",

-      "print(\"pf=%.4f\" %pf)\n",

-      "f1=50\n",

-      "w_s=4*math.pi*f1/4\n",

-      "T_en=(3/w_s)*I_n**2*(r2/s)    \n",

-      "print(\"\\nTorque developed=%.2f Nm\" %T_en)\n",

-      "print(\"motor is operated with DOL starting\")\n",

-      "I_d=V1/2/math.sqrt((r1+r2/s)**2+((x1+x2)/2)**2)    \n",

-      "print(\"current=%.0f A\" %I_d)\n",

-      "pf=(r1+r2)/math.sqrt((r1+r2/s)**2+((x1+x2)/2)**2)    \n",

-      "print(\"pf=%.2f\" %pf)\n",

-      "f1=25\n",

-      "w_s=4*math.pi*f1/4\n",

-      "T_ed=(3/w_s)*I_d**2*(r2/s)    \n",

-      "print(\"Torque developed=%.3f Nm\" %T_ed)\n",

-      "print(\"at max torque conditions\")\n",

-      "s_mn=r2/math.sqrt((r1)**2+((x1+x2))**2)\n",

-      "I_n=V1/math.sqrt((r1+r2/s_mn)**2+(x1+x2)**2)    \n",

-      "print(\"current=%.3f A\" %I_n)\n",

-      "pf=(r1+r2/s_mn)/math.sqrt((r1+r2/s_mn)**2+(x1+x2)**2)    \n",

-      "print(\"pf=%.4f\" %pf)\n",

-      "f1=50\n",

-      "w_s=4*math.pi*f1/4\n",

-      "T_en=(3/w_s)*I_n**2*(r2/s_mn)    \n",

-      "print(\"Torque developed=%.2f Nm\" %T_en)\n",

-      "print(\"motor is operated with DOL starting\")\n",

-      "s_mn=r2/math.sqrt((r1)**2+((x1+x2)/2)**2)\n",

-      "I_d=V1/2/math.sqrt((r1+r2/s_mn)**2+((x1+x2)/2)**2)    \n",

-      "print(\"current=%.3f A\" %I_d)\n",

-      "pf=(r1+r2/s_mn)/math.sqrt((r1+r2/s_mn)**2+((x1+x2)/2)**2)    \n",

-      "print(\"\\npf=%.3f\" %pf)\n",

-      "f1=25\n",

-      "w_s=4*math.pi*f1/4\n",

-      "T_en=(3/w_s)*I_d**2*(r2/s_mn)  \n",

-      "\n",

-      "\n",

-      "#Results  \n",

-      "print(\"Torque developed=%.3f Nm\" %T_en)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "at starting in normal conditions\n",

-        "current=119.31 A\n",

-        "pf=0.2983\n",

-        "\n",

-        "Torque developed=108.75 Nm\n",

-        "motor is operated with DOL starting\n",

-        "current=106 A\n",

-        "pf=0.53\n",

-        "Torque developed=171.673 Nm\n",

-        "at max torque conditions\n",

-        "current=79.829 A\n",

-        "pf=0.7695\n",

-        "Torque developed=396.26 Nm\n",

-        "motor is operated with DOL starting\n",

-        "current=71.199 A\n",

-        "\n",

-        "pf=0.822\n",

-        "Torque developed=330.883 Nm\n"

-       ]

-      }

-     ],

-     "prompt_number": 21

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.25, Page No 709"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "x1=1.0\n",

-      "X_m=50.0\n",

-      "X_e=x1*X_m/(x1+X_m)\n",

-      "V=231.0\n",

-      "V_e=V*X_m/(x1+X_m)\n",

-      "x2=1.0\n",

-      "r2=.4\n",

-      "r1=0\n",

-      "\n",

-      "#Calculations\n",

-      "s_m=r2/(x2+X_e)    \n",

-      "print(\"slip at max torque=%.2f\" %s_m)\n",

-      "s_mT=r2/(x2+X_m)    \n",

-      "print(\"slip at max torque=%.5f\" %s_mT)\n",

-      "f1=50.0\n",

-      "w_s=4*math.pi*f1/4\n",

-      "print(\"for constant voltage input\")\n",

-      "T_est=(3/w_s)*(V_e/math.sqrt(r2**2+(x2+X_e)**2))**2*(r2)    \n",

-      "print(\"starting torque=%.3f Nm\" %T_est)\n",

-      "T_em=(3/w_s)*V_e**2/(2*(x2+X_e))    \n",

-      "print(\"maximum torque developed=%.2f Nm\" %T_em)\n",

-      "print(\"for constant current input\")\n",

-      "I1=28\n",

-      "T_est=(3/w_s)*(I1*X_m)**2/(r2**2+(x2+X_m)**2)*r2    \n",

-      "print(\"starting torque=%.3f Nm\" %T_est)\n",

-      "T_em=(3/w_s)*(I1*X_m)**2/(2*(x2+X_m))   \n",

-      "print(\"maximum torque developed=%.3f Nm\" %T_em)\n",

-      "s=s_mT\n",

-      "i=1\n",

-      "I_m=I1*(r2/s+i*x2)/(r2/s+i*(x2+X_m))\n",

-      "I_m=math.fabs(I_m)\n",

-      "V1=math.sqrt(3)*I_m*X_m    \n",

-      "\n",

-      "#Results\n",

-      "print(\"supply voltage reqd=%.1f V\" %V1)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "slip at max torque=0.20\n",

-        "slip at max torque=0.00784\n",

-        "for constant voltage input\n",

-        "starting torque=95.988 Nm\n",

-        "maximum torque developed=247.31 Nm\n",

-        "for constant current input\n",

-        "starting torque=5.756 Nm\n",

-        "maximum torque developed=366.993 Nm\n",

-        "supply voltage reqd=1236.2 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 22

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.27, Page No 718"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=420.0\n",

-      "V1=V/math.sqrt(3)\n",

-      "T_e=450.0\n",

-      "N=1440.0\n",

-      "n=1000.0\n",

-      "T_L=T_e*(n/N)**2\n",

-      "n1=1500.0\n",

-      "\n",

-      "#Calculations\n",

-      "w_s=2*math.pi*n1/60\n",

-      "w_m=2*math.pi*n/60\n",

-      "a=.8\n",

-      "I_d=T_L*w_s/(2.339*a*V1)\n",

-      "k=0\n",

-      "R=(1-w_m/w_s)*(2.339*a*V1)/(I_d*(1-k))    \n",

-      "print(\"value of chopper resistance=%.4f ohm\" %R)\n",

-      "n=1320.0\n",

-      "T_L=T_e*(n/N)**2\n",

-      "I_d=T_L*w_s/(2.339*a*V1)    \n",

-      "print(\"Inductor current=%.3f A\" %I_d)\n",

-      "w_m=2*math.pi*n/60\n",

-      "k=1-((1-w_m/w_s)*(2.339*a*V1)/(I_d*R))    \n",

-      "print(\"value of duty cycle=%.4f\" %k)\n",

-      "s=(n1-n)/n1\n",

-      "V_d=2.339*s*a*V1    \n",

-      "print(\"Rectifed o/p voltage=%.3f V\" %V_d)\n",

-      "P=V_d*I_d\n",

-      "I2=math.sqrt(2/3)*I_d\n",

-      "r2=0.02\n",

-      "Pr=3*I2**2*r2\n",

-      "I1=a*I2\n",

-      "r1=0.015\n",

-      "Ps=3*I1**2*r1\n",

-      "Po=T_L*w_m\n",

-      "Pi=Po+Ps+Pr+P\n",

-      "eff=Po/Pi*100   \n",

-      "\n",

-      "#Results\n",

-      "print(\"Efficiency(in percent)=%.2f\" %eff)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "value of chopper resistance=2.0132 ohm\n",

-        "Inductor current=130.902 A\n",

-        "value of duty cycle=0.7934\n",

-        "Rectifed o/p voltage=54.449 V\n",

-        "Efficiency(in percent)=88.00\n"

-       ]

-      }

-     ],

-     "prompt_number": 23

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.28, Page No 720"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=400.0\n",

-      "V_ph=V/math.sqrt(3)\n",

-      "N_s=1000.0\n",

-      "N=800.0\n",

-      "a=.7\n",

-      "I_d=110\n",

-      "R=2.0\n",

-      "\n",

-      "#Calculations\n",

-      "k=1-((1-N/N_s)*(2.339*a*V_ph)/(I_d*R))    \n",

-      "print(\"value of duty cycle=%.3f\" %k)\n",

-      "P=I_d**2*R*(1-k)\n",

-      "I1=a*I_d*math.sqrt(2/3)\n",

-      "r1=0.1\n",

-      "r2=0.08\n",

-      "Pr=3*I1**2*(r1+r2)\n",

-      "P_o=20000\n",

-      "P_i=P_o+Pr+P\n",

-      "eff=P_o/P_i*100    \n",

-      "print(\"Efficiency=%.2f\" %eff)\n",

-      "I11=math.sqrt(6)/math.pi*a*I_d\n",

-      "th=43\n",

-      "P_ip=math.sqrt(3)*V*I11*math.cos(math.radians(th))\n",

-      "pf=P_ip/(math.sqrt(3)*V*I11)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"Input power factor=%.4f\" %pf)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "value of duty cycle=0.656\n",

-        "Efficiency=70.62\n",

-        "Input power factor=0.7314\n"

-       ]

-      }

-     ],

-     "prompt_number": 24

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.29, Page No 724"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=420.0\n",

-      "V1=V/math.sqrt(3)\n",

-      "N=1000.0\n",

-      "w_m=2*math.pi*N/60\n",

-      "N_s=1500.0\n",

-      "\n",

-      "#Calculations\n",

-      "s=(N_s-N)/N_s\n",

-      "a=0.8\n",

-      "V_d=2.339*a*s*V1    \n",

-      "print(\"rectified voltage=%.2f V\" %V_d)\n",

-      "T=450.0\n",

-      "N1=1200.0\n",

-      "T_L=T*(N/N1)**2\n",

-      "f1=50\n",

-      "w_s=4*math.pi*f1/4\n",

-      "I_d=w_s*T_L/(2.339*a*V1)    \n",

-      "print(\"inductor current=%.2f A\" %I_d)\n",

-      "a_T=-.4\n",

-      "a1=math.degrees(math.acos(s*a/a_T))\n",

-      "print(\"delay angle of inverter=%.2f deg\" %a1)\n",

-      "\n",

-      "P_s=V_d*I_d\n",

-      "P_o=T_L*w_m\n",

-      "R_d=0.01\n",

-      "P_i=I_d**2*R_d\n",

-      "I2=math.sqrt(2/3)*I_d\n",

-      "r2=0.02\n",

-      "r1=0.015\n",

-      "P_rol=3*I2**2*r2\n",

-      "I1=a*I2\n",

-      "P_sol=3*I1**2*r1\n",

-      "P_i=P_o+P_rol+P_sol+P_i\n",

-      "eff=P_o/P_i*100    \n",

-      "print(\"\\nefficiency=%.2f\" %eff)\n",

-      "w_m=w_s*(1+(-a_T/a)*math.cos(math.radians(a1))-w_s*R_d*T_L/(2.339*a*V1)**2)\n",

-      "N=w_m*60/(2*math.pi) \n",

-      "\n",

-      "#Results   \n",

-      "print(\"motor speed=%.1f rpm\" %N)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rectified voltage=151.25 V\n",

-        "inductor current=108.18 A\n",

-        "delay angle of inverter=131.81 deg\n",

-        "\n",

-        "efficiency=99.64\n",

-        "motor speed=996.4 rpm\n"

-       ]

-      }

-     ],

-     "prompt_number": 25

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.30, Page No 726"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=700.0\n",

-      "E2=V/math.sqrt(3)\n",

-      "N_s=1500.0\n",

-      "N=1200.0\n",

-      "\n",

-      "#Calculations\n",

-      "s=(N_s-N)/N_s\n",

-      "V_dd=0.7\n",

-      "V_dt=1.5\n",

-      "V_d=3*math.sqrt(6)*s*E2/math.pi-2*V_dd\n",

-      "V1=415.0\n",

-      "a=math.degrees(math.acos((3*math.sqrt(2)*E2/math.pi)**-1*(-V_d+2*V_dt)))\n",

-      "\n",

-      "#Results\n",

-      "print(\"firing angle advance=%.2f deg\" %(180-a))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "firing angle advance=70.22 deg\n"

-       ]

-      }

-     ],

-     "prompt_number": 26

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.31, Page No 726"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=700.0\n",

-      "E2=V/math.sqrt(3)\n",

-      "N_s=1500.0\n",

-      "N=1200.0\n",

-      "\n",

-      "#Calculations\n",

-      "s=(N_s-N)/N_s\n",

-      "V_dd=.7\n",

-      "V_dt=1.5\n",

-      "a=0\n",

-      "u=18 #overlap angle in case of rectifier\n",

-      "V_d=3*math.sqrt(6)*s*E2*(math.cos(math.radians(a))+math.cos(math.radians(a+u)))/(2*math.pi)-2*V_dd\n",

-      "V1=415\n",

-      "V_ml=math.sqrt(2)*V1\n",

-      "u=4 #overlap anglein the inverter\n",

-      " #V_dc=-(3*V_ml*(math.cos(math.radians(a))+math.cos(math.radians(a+u)))/(2*math.pi)-2*V_dt)\n",

-      " #V_dc=V_d\n",

-      " #after solving %  (1+math.cos(math.radians(u)))*math.cos(math.radians(a))-math.sin(math.radians(u))*math.sin(math.radians(a))=-.6425\n",

-      "a=math.degrees(math.acos(-.6425/(math.sqrt((1+math.cos(math.radians(u)))**2+math.sin(math.radians(u))**2))))-math.degrees(math.asin(math.sin(math.radians(a))/(1+math.cos(math.radians(u)))))\n",

-      "\n",

-      "#Results\n",

-      "print(\"firing angle advance=%.2f deg\" %(180-a))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "firing angle advance=71.25 deg\n"

-       ]

-      }

-     ],

-     "prompt_number": 27

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.32, Page No 727"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=700.0\n",

-      "E2=V\n",

-      "N_s=1500.0\n",

-      "N=1200.0\n",

-      "\n",

-      "#Calculations\n",

-      "s=(N_s-N)/N_s\n",

-      "V1=415.0\n",

-      "a_T=s*E2/V1    \n",

-      "\n",

-      "#Results\n",

-      "print(\"voltage ratio of the transformer=%.2f\" %a_T)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "voltage ratio of the transformer=0.34\n"

-       ]

-      }

-     ],

-     "prompt_number": 28

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.33, Page No 733"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "P=6.0\n",

-      "N_s=600.0\n",

-      "f1=P*N_s/120.0\n",

-      "V=400.0\n",

-      "f=50.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_t=f1*V/f    \n",

-      "print(\"supply freq=%.0f Hz\" %V_t)\n",

-      "T=340.0\n",

-      "N=1000.0\n",

-      "T_L=T*(N_s/N)**2\n",

-      "w_s=2*math.pi*N_s/60\n",

-      "P=T_L*w_s\n",

-      "I_a=P/(math.sqrt(3)*V_t)    \n",

-      "print(\"armature current=%.2f A\" %I_a)\n",

-      "Z_s=2\n",

-      "X_s=f1/f*math.fabs(Z_s)\n",

-      "V_t=V_t/math.sqrt(3)\n",

-      "Ef=math.sqrt(V_t**2+(I_a*X_s)**2)\n",

-      "print(\"excitation voltage=%.2f V\" %(math.sqrt(3)*Ef))\n",

-      "dl=math.degrees(math.atan(I_a*X_s/V_t))\n",

-      "print(\"load angle=%.2f deg\" %dl)\n",

-      "T_em=(3/w_s)*(Ef*V_t/X_s)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"pull out torque=%.2f Nm\" %T_em)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "supply freq=240 Hz\n",

-        "armature current=18.50 A\n",

-        "excitation voltage=243.06 V\n",

-        "load angle=9.10 deg\n",

-        "pull out torque=773.69 Nm\n"

-       ]

-      }

-     ],

-     "prompt_number": 29

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.34, Page No 736"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "P=4.0\n",

-      "f=50.0\n",

-      "w_s=4*math.pi*f/P\n",

-      "X_d=8.0\n",

-      "X_q=2.0\n",

-      "T_e=80.0\n",

-      "V=400.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_t=V/math.sqrt(3)\n",

-      "dl=(1/2)*math.degrees(math.asin(T_e*w_s/((3/2)*(V_t)**2*(1/X_q-1/X_d))))    \n",

-      "print(\"load angle=%.3f deg\" %dl)\n",

-      "I_d=V_t*math.cos(math.radians(dl))/X_d\n",

-      "I_q=V_t*math.sin(math.radians(dl))/X_q\n",

-      "I_a=math.sqrt(I_d**2+I_q**2)    \n",

-      "print(\"armature current=%.2f A\" %I_a)\n",

-      "pf=T_e*w_s/(math.sqrt(3)*V*I_a)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"input power factor=%.4f\" %pf)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "load angle=0.000 deg\n",

-        "armature current=28.87 A\n",

-        "input power factor=0.6283\n"

-       ]

-      }

-     ],

-     "prompt_number": 30

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.35, Page No 737"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "T_e=3.0\n",

-      "K_m=1.2\n",

-      "I_a=T_e/K_m\n",

-      "r_a=2.0\n",

-      "V=230.0\n",

-      "\n",

-      "#Calculations\n",

-      "E_a=(0.263*math.sqrt(2)*V-I_a*r_a)/(1-55/180)\n",

-      "w_m=E_a/K_m\n",

-      "N=w_m*60/(2*math.pi)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"motor speed=%.2f rpm\" %N)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "motor speed=640.96 rpm\n"

-       ]

-      }

-     ],

-     "prompt_number": 31

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.36, Page No 738"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "K_m=1.0\n",

-      "N=1360.0\n",

-      "\n",

-      "#Calculations\n",

-      "w_m=2*math.pi*N/60\n",

-      "E_a=K_m*w_m\n",

-      " #after calculations V_t % calculated\n",

-      "V_t=163.45\n",

-      "r_a=4\n",

-      "I_a=(V_t-E_a)/r_a\n",

-      "T_e=K_m*I_a    \n",

-      "\n",

-      "#Results\n",

-      "print(\"motor torque=%.4f Nm\" %T_e)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "motor torque=5.2578 Nm\n"

-       ]

-      }

-     ],

-     "prompt_number": 32

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.37, Page No 740"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "K_m=1.0\n",

-      "N=2100.0\n",

-      "\n",

-      "#Calculations\n",

-      "w_m=2*math.pi*N/60\n",

-      "E_a=K_m*w_m\n",

-      " #after calculations V_t % calculated\n",

-      "V_t=227.66\n",

-      "r_a=4\n",

-      "I_a=(V_t-E_a)/r_a\n",

-      "T_e=K_m*I_a    \n",

-      "\n",

-      "#Results\n",

-      "print(\"motor torque=%.2f Nm\" %T_e)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "motor torque=1.94 Nm\n"

-       ]

-      }

-     ],

-     "prompt_number": 33

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.38, Page No 742"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "K_m=1.0\n",

-      "N=840.0\n",

-      "\n",

-      "#Calculations\n",

-      "w_m=2*math.pi*N/60\n",

-      "E_a=K_m*w_m\n",

-      "V=230.0\n",

-      "a=75.0\n",

-      "V_t=math.sqrt(2)*V/math.pi*(1+math.cos(math.radians(a)))\n",

-      "r_a=4\n",

-      "I_a=(V_t-E_a)/r_a\n",

-      "T_e=K_m*I_a    \n",

-      "\n",

-      "#Results\n",

-      "print(\"motor torque=%.4f Nm\" %T_e)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits.\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "motor torque=10.5922 Nm\n"

-       ]

-      }

-     ],

-     "prompt_number": 34

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.39, Page No 743"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "K_m=1.0\n",

-      "N=1400.0\n",

-      "\n",

-      "#Calculations\n",

-      "w_m=2*math.pi*N/60\n",

-      "E_a=K_m*w_m\n",

-      "V=230.0\n",

-      "a=60.0\n",

-      "a1=212\n",

-      "V_t=math.sqrt(2)*V/math.pi*(math.cos(math.radians(a))-math.cos(math.radians(a1)))+E_a*(180+a-a1)/180\n",

-      "r_a=3\n",

-      "I_a=(V_t-E_a)/r_a\n",

-      "T_e=K_m*I_a   \n",

-      "\n",

-      "#Results\n",

-      "print(\"motor torque=%.3f Nm\" %T_e)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "motor torque=5.257 Nm\n"

-       ]

-      }

-     ],

-     "prompt_number": 35

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.40, Page No 745"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "K_m=1.0\n",

-      "N=600.0\n",

-      "w_m=2*math.pi*N/60\n",

-      "E_a=K_m*w_m\n",

-      "V=230.0\n",

-      "a=60.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_t=2*math.sqrt(2)*V/math.pi*(math.cos(math.radians(a)))\n",

-      "r_a=3\n",

-      "I_a=(V_t-E_a)/r_a\n",

-      "T_e=K_m*I_a    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"motor torque=%.3f Nm\" %T_e)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "motor torque=13.568 Nm\n"

-       ]

-      }

-     ],

-     "prompt_number": 36

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.41, Page No 745"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "r1=.6\n",

-      "r2=.4\n",

-      "s=0.04\n",

-      "x1=1.6\n",

-      "x2=1.6\n",

-      "Z=(r1+r2/s)+(x1+x2)\n",

-      "V=400.0\n",

-      "I1=V/Z    \n",

-      "print(\"source current=%.3f A \" %math.degrees(math.atan(I1.imag/I1.real)))\n",

-      "print(\"and with %.1f deg phase\" %math.fabs(I1))\n",

-      "I2=V/Z\n",

-      "N=1500\n",

-      "w_s=2*math.pi*N/60\n",

-      "T_e=(3/w_s)*abs(I2)**2*r2/s    \n",

-      "print(\"motor torque=%.2f Nm\" %T_e)\n",

-      "N_r=N*(1-s)\n",

-      "\n",

-      "f=45\n",

-      "N_s1=120*f/4\n",

-      "w_s=2*math.pi*N_s1/60\n",

-      "s1=(N_s1-N_r)/N_s1\n",

-      "Z=(r1+r2/s1)+(x1+x2)*f/50.0\n",

-      "V=360\n",

-      "I1=V/Z    \n",

-      "print(\"source current=%.3f A \" %math.degrees(math.atan(I1.imag/I1.real)))\n",

-      "print(\"and with %.1f deg phase\" %math.fabs(I1))\n",

-      "I2=V/Z\n",

-      "T_e=(3/w_s)*abs(I2)**2*r2/s1    \n",

-      "print(\"motor torque=%.2f Nm\" %T_e)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "source current=0.000 A \n",

-        "and with 29.0 deg phase\n",

-        "motor torque=160.46 Nm\n",

-        "source current=-0.000 A \n",

-        "and with 142.9 deg phase\n",

-        "motor torque=-2598.45 Nm\n"

-       ]

-      }

-     ],

-     "prompt_number": 37

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Power_Electronics/Chapter12_2.ipynb b/_Power_Electronics/Chapter12_2.ipynb
deleted file mode 100755
index f8605d69..00000000
--- a/_Power_Electronics/Chapter12_2.ipynb
+++ /dev/null
@@ -1,1997 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 12 : Electic Drives"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.1, Page No 658"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "T_e=15.0 #Nm\n",

-      "K_m=0.5 #V-s/rad\n",

-      "I_a=T_e/K_m\n",

-      "n_m=1000.0\n",

-      "\n",

-      "#Calculations\n",

-      "w_m=2*math.pi*n_m/60\n",

-      "E_a=K_m*w_m\n",

-      "r_a=0.7\n",

-      "V_t=E_a+I_a*r_a\n",

-      "V_s=230.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "a=math.degrees(math.acos(2*math.pi*V_t/V_m-1))\n",

-      "print(\"firing angle delay=%.3f deg\" %a)\n",

-      "I_Tr=I_a*math.sqrt((180-a)/360)    \n",

-      "print(\"rms value of thyristor current=%.3f A\" %I_Tr)\n",

-      "I_fdr=I_a*math.sqrt((180+a)/360)    \n",

-      "print(\"rms value of freewheeling diode current=%.3f A\" %I_fdr)\n",

-      "pf=V_t*I_a/(V_s*I_Tr)  \n",

-      "\n",

-      "#Results  \n",

-      "print(\"input power factor=%.4f\" %pf)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "firing angle delay=65.349 deg\n",

-        "rms value of thyristor current=16.930 A\n",

-        "rms value of freewheeling diode current=24.766 A\n",

-        "input power factor=0.5652\n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.2, Page No 660"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=230.0\n",

-      "E=150.0\n",

-      "R=8.0\n",

-      "\n",

-      "#Calculations\n",

-      "th1=math.sin(math.radians(E/(math.sqrt(2)*V)))\n",

-      "I_o=(1/(2*math.pi*R))*(2*math.sqrt(2)*230*math.cos(math.radians(th1))-E*(math.pi-2*th1*math.pi/180))    \n",

-      "P=E*I_o    \n",

-      "I_or=math.sqrt((1/(2*math.pi*R**2))*((V**2+E**2)*(math.pi-2*th1*math.pi/180)+V**2*math.sin(math.radians(2*th1))-4*math.sqrt(2)*V*E*math.cos(math.radians(th1))))\n",

-      "P_r=I_or**2*R    \n",

-      "pf=(P+P_r)/(V*I_or)\n",

-      "\n",

-      "#Results\n",

-      "print(\"avg charging curent=%.4f A\" %I_o)\n",

-      "print(\"power supplied to the battery=%.2f W\" %P)\n",

-      "print(\"power dissipated by the resistor=%.3f W\" %P_r)    \n",

-      "print(\"supply pf=%.3f\" %pf)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "avg charging curent=3.5679 A\n",

-        "power supplied to the battery=535.18 W\n",

-        "power dissipated by the resistor=829.760 W\n",

-        "supply pf=0.583\n"

-       ]

-      }

-     ],

-     "prompt_number": 2

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.3 Page No 661"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variablesV_s=250\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "a=30.0\n",

-      "k=0.03 #Nm/A**2\n",

-      "n_m=1000.0\n",

-      "\n",

-      "#Calculations\n",

-      "w_m=2*math.pi*n_m/60\n",

-      "r=.2 #r_a+r_s\n",

-      "V_t=V_m/math.pi*(1+math.cos(math.radians(a)))\n",

-      "I_a=V_t/(k*w_m+r)   \n",

-      "print(\"motor armature current=%.2f A\" %I_a)\n",

-      "T_e=k*I_a**2    \n",

-      "print(\"motor torque=%.3f Nm\" %T_e)\n",

-      "I_sr=I_a*math.sqrt((180-a)/180)\n",

-      "pf=(V_t*I_a)/(V_s*I_sr)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"input power factor=%.2f\" %pf)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "motor armature current=57.82 A\n",

-        "motor torque=100.285 Nm\n",

-        "input power factor=0.92\n"

-       ]

-      }

-     ],

-     "prompt_number": 3

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.4, Page No 663"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=400.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "V_f=2*V_m/math.pi\n",

-      "r_f=200.0\n",

-      "I_f=V_f/r_f\n",

-      "T_e=85.0\n",

-      "K_a=0.8\n",

-      "\n",

-      "#Calculations\n",

-      "I_a=T_e/(I_f*K_a)    \n",

-      "print(\"rated armature current=%.2f A\" %I_a)\n",

-      "n_m=1200.0\n",

-      "w_m=2*math.pi*n_m/60\n",

-      "r_a=0.2\n",

-      "V_t=K_a*I_f*w_m+I_a*r_a\n",

-      "a=math.degrees(math.acos(V_t*math.pi/(2*V_m)))\n",

-      "print(\"firing angle delay=%.2f deg\" %a)\n",

-      "E_a=V_t\n",

-      "w_mo=E_a/(K_a*I_f)\n",

-      "N=60*w_mo/(2*math.pi)\n",

-      "reg=((N-n_m)/n_m)*100    \n",

-      "print(\"speed regulation at full load=%.2f\" %reg)\n",

-      "I_ar=I_a\n",

-      "pf=(V_t*I_a)/(V_s*I_ar)    \n",

-      "print(\"input power factor of armature convertor=%.4f\" %pf)\n",

-      "I_fr=I_f\n",

-      "I_sr=math.sqrt(I_fr**2+I_ar**2)\n",

-      "VA=I_sr*V_s\n",

-      "P=V_t*I_a+V_f*I_f\n",

-      "\n",

-      "#Results\n",

-      "print(\"input power factor of drive=%.4f\" %(P/VA))\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rated armature current=59.01 A\n",

-        "firing angle delay=57.63 deg\n",

-        "speed regulation at full load=6.52\n",

-        "input power factor of armature convertor=0.4821\n",

-        "input power factor of drive=0.5093\n"

-       ]

-      }

-     ],

-     "prompt_number": 4

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.5 Page No 664"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=400.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "V_f=2*V_m/math.pi\n",

-      "\n",

-      "#Calculations\n",

-      "a1=math.degrees(math.acos(V_t*math.pi/(2*V_m))) \n",

-      "print(\"delay angle of field converter=%.0f deg\" %a1)\n",

-      "r_f=200.0\n",

-      "I_f=V_f/r_f\n",

-      "T_e=85.0\n",

-      "K_a=0.8\n",

-      "I_a=T_e/(I_f*K_a)\n",

-      "n_m=1200.0\n",

-      "w_m=2*math.pi*n_m/60\n",

-      "r_a=0.1\n",

-      "I_a=50.0\n",

-      "V_t=-K_a*I_f*w_m+I_a*r_a\n",

-      "a=math.degrees(math.acos(V_t*math.pi/(2*V_m)))\n",

-      "\n",

-      "#Results\n",

-      "print(\"firing angle delay of armature converter=%.3f deg\" %a)\n",

-      "print(\"power fed back to ac supply=%.0f W\" %(-V_t*I_a))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "delay angle of field converter=58 deg\n",

-        "firing angle delay of armature converter=119.260 deg\n",

-        "power fed back to ac supply=8801 W\n"

-       ]

-      }

-     ],

-     "prompt_number": 5

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.6 Page No 665"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_t=220.0\n",

-      "n_m=1500.0\n",

-      "w_m=2*math.pi*n_m/60\n",

-      "I_a=10.0\n",

-      "r_a=1.0\n",

-      "\n",

-      "#Calculations\n",

-      "K_m=(V_t-I_a*r_a)/(w_m)\n",

-      "T=5.0\n",

-      "I_a=T/K_m\n",

-      "V_s=230.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "a=30.0\n",

-      "V_t=2*V_m*math.cos(math.radians(a))/math.pi\n",

-      "w_m=(V_t-I_a*r_a)/K_m\n",

-      "N=w_m*60/(2*math.pi)    \n",

-      "\n",

-      "print(\"motor speed=%.2f rpm\" %N)\n",

-      "a=45\n",

-      "n_m=1000\n",

-      "w_m=2*math.pi*n_m/60\n",

-      "V_t=2*V_m*math.cos(math.radians(a))/math.pi\n",

-      "I_a=(V_t-K_m*w_m)/r_a\n",

-      "T_e=K_m*I_a    \n",

-      "\n",

-      "#Results\n",

-      "print(\"torque developed=%.3f Nm\" %T_e)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "motor speed=1254.22 rpm\n",

-        "torque developed=8.586 Nm\n"

-       ]

-      }

-     ],

-     "prompt_number": 6

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.7, Page No 666"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_t=220.0\n",

-      "n_m=1000.0\n",

-      "w_m=2*math.pi*n_m/60\n",

-      "I_a=60.0\n",

-      "r_a=.1\n",

-      "\n",

-      "#Calculations\n",

-      "K_m=(V_t-I_a*r_a)/(w_m)\n",

-      "V_s=230\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "print(\"for 600rpm speed\")\n",

-      "n_m=600.0\n",

-      "w_m=2*math.pi*n_m/60\n",

-      "a=math.degrees(math.acos((K_m*w_m+I_a*r_a)*math.pi/(2*V_m))) \n",

-      "print(\"firing angle=%.3f deg\" %a)\n",

-      "print(\"for -500rpm speed\")\n",

-      "n_m=-500.0\n",

-      "w_m=2*math.pi*n_m/60\n",

-      "a=math.degrees(math.acos((K_m*w_m+I_a*r_a)*math.pi/(2*V_m)))\n",

-      "print(\"firing angle=%.2f deg\" %a)\n",

-      "I_a=I_a/2\n",

-      "a=150\n",

-      "V_t=2*V_m*math.cos(math.radians(a))/math.pi\n",

-      "w_m=(V_t-I_a*r_a)/K_m\n",

-      "N=w_m*60/(2*math.pi)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"motor speed=%.3f rpm\" %N)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for 600rpm speed\n",

-        "firing angle=49.530 deg\n",

-        "for -500rpm speed\n",

-        "firing angle=119.19 deg\n",

-        "motor speed=-852.011 rpm\n"

-       ]

-      }

-     ],

-     "prompt_number": 7

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.8 Page No 672"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "K_m=1.5\n",

-      "T_e=50.0\n",

-      "I_a=T_e/K_m\n",

-      "r_a=0.9\n",

-      "a=45.0\n",

-      "V_s=415.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_ml=math.sqrt(2)*V_s\n",

-      "w_m=((3*V_ml*(1+math.cos(math.radians(a)))/(2*math.pi))-I_a*r_a)/K_m\n",

-      "N=w_m*60/(2*math.pi)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"motor speed=%.2f rpm\" %N)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "motor speed=2854.42 rpm\n"

-       ]

-      }

-     ],

-     "prompt_number": 8

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.9 Page No 672"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variablesV_t=600\n",

-      "n_m=1500.0\n",

-      "w_m=2*math.pi*n_m/60\n",

-      "I_a=80.0\n",

-      "r_a=1.0\n",

-      "\n",

-      "#Calculations\n",

-      "K_m=(V_t-I_a*r_a)/(w_m)\n",

-      "V_s=400.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "print(\"for firing angle=45deg and speed=1200rpm\")\n",

-      "a=45.0\n",

-      "n_m=1200.0\n",

-      "w_m=2*math.pi*n_m/60\n",

-      "I_a=(3*V_m*(1+math.cos(math.radians(a)))/(2*math.pi)-K_m*w_m)/r_a\n",

-      "I_sr=I_a*math.sqrt(2/3)    \n",

-      "print(\"rms value of source current=%.3f A\" %I_sr)\n",

-      "print(\"rms value of thyristor current=%.3f A\" %(I_a*math.sqrt(1/3)))\n",

-      "print(\"avg value of thyristor current=%.2f A\" %I_a*(1/3))\n",

-      "pf=(3/(2*math.pi)*(1+math.cos(math.radians(a))))    \n",

-      "print(\"input power factor=%.3f\" %pf)\n",

-      "\n",

-      "print(\"for firing angle=90deg and speed=700rpm\")\n",

-      "a=90\n",

-      "n_m=700\n",

-      "w_m=2*math.pi*n_m/60\n",

-      "I_a=(3*V_m*(1+math.cos(math.radians(a)))/(2*math.pi)-K_m*w_m)/r_a\n",

-      "I_sr=I_a*math.sqrt(90/180)    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"rms value of source current=%.3f A\" %I_sr)\n",

-      "print(\"rms value of thyristor current=%.3f A\" %(I_a*math.sqrt(90.0/360)))\n",

-      "print(\"avg value of thyristor current=%.3f A\" %I_a*(1/3))\n",

-      "pf=(math.sqrt(6)/(2*math.pi)*(1+math.cos(math.radians(a))))*math.sqrt(180/(180-a))    \n",

-      "print(\"input power factor=%.4f\" %pf)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for firing angle=45deg and speed=1200rpm\n",

-        "rms value of source current=0.000 A\n",

-        "rms value of thyristor current=0.000 A\n",

-        "\n",

-        "input power factor=0.815\n",

-        "for firing angle=90deg and speed=700rpm\n",

-        "rms value of source current=0.000 A\n",

-        "rms value of thyristor current=195.558 A\n",

-        "\n",

-        "input power factor=0.5513\n"

-       ]

-      }

-     ],

-     "prompt_number": 9

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.10 Page No 676"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=400.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "a=30\n",

-      "V_t=3*V_m*math.cos(math.radians(a))/math.pi\n",

-      "I_a=21.0\n",

-      "r_a=.1\n",

-      "V_d=2.0\n",

-      "K_m=1.6\n",

-      "\n",

-      "#Calculations\n",

-      "w_m=(V_t-I_a*r_a-V_d)/K_m\n",

-      "N=w_m*60/(2*math.pi)    \n",

-      "print(\"speed of motor=%.1f rpm\" %N)\n",

-      "\n",

-      "N=2000\n",

-      "w_m=2*math.pi*N/60\n",

-      "I_a=210\n",

-      "V_t=K_m*w_m+I_a*r_a+V_d\n",

-      "a=math.degrees(math.acos(V_t*math.pi/(3*V_m)))\n",

-      "print(\"firing angle=%.2f deg\" %a)\n",

-      "I_sr=I_a*math.sqrt(2.0/3.0)\n",

-      "pf=V_t*I_a/(math.sqrt(3)*V_s*I_sr)    \n",

-      "print(\"supply power factor=%.3f\" %pf)\n",

-      "\n",

-      "I_a=21\n",

-      "w_m=(V_t-I_a*r_a-V_d)/K_m\n",

-      "n=w_m*60/(2*math.pi)\n",

-      "reg=(n-N)/N*100    \n",

-      "\n",

-      "#Results\n",

-      "print(\"speed regulation(percent)=%.2f\" %reg)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "speed of motor=2767.6 rpm\n",

-        "firing angle=48.48 deg\n",

-        "supply power factor=0.633\n",

-        "speed regulation(percent)=5.64\n"

-       ]

-      }

-     ],

-     "prompt_number": 10

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.11, Page No 677"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_t=230.0\n",

-      "V_l=V_t*math.pi/(3*math.sqrt(2))\n",

-      "V_ph=V_l/math.sqrt(3)\n",

-      "V_in=400     #per phase voltage input\n",

-      "\n",

-      "#Calculations\n",

-      "N1=1500.0\n",

-      "I_a1=20.0\n",

-      "r_a1=.6\n",

-      "E_a1=V_t-I_a1*r_a1\n",

-      "n1=1000.0\n",

-      "E_a2=E_a1/1500.0*1000.0\n",

-      "V_t1=E_a1+I_a1*r_a1\n",

-      "a1=math.degrees(math.acos(V_t1*math.pi/(3*math.sqrt(2.0)*V_l)))\n",

-      "I_a2=.5*I_a1\n",

-      "n2=-900.0\n",

-      "V_t2=n2*E_a2/N1+I_a2*r_a1\n",

-      "a2=math.degrees(math.acos(V_t2*math.pi/(3*math.sqrt(2)*V_l))) \n",

-      "\n",

-      "#Results\n",

-      "print(\"transformer phase turns ratio=%.3f\" %(V_in/V_ph))\n",

-      "print(\"for motor running at 1000rpm at rated torque\")\n",

-      "print(\"firing angle delay=%.2f deg\" %a1)\n",

-      "print(\"for motor running at -900rpm at half of rated torque\")\n",

-      "print(\"firing angle delay=%.3f deg\" %a2)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "transformer phase turns ratio=4.068\n",

-        "for motor running at 1000rpm at rated torque\n",

-        "firing angle delay=0.00 deg\n",

-        "for motor running at -900rpm at half of rated torque\n",

-        "firing angle delay=110.674 deg\n"

-       ]

-      }

-     ],

-     "prompt_number": 11

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.12, Page No 678"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variablesV_s=400\n",

-      "V_ml=math.sqrt(2)*V_s\n",

-      "V_f=3*V_ml/math.pi\n",

-      "R_f=300.0\n",

-      "I_f=V_f/R_f\n",

-      "T_e=60.0\n",

-      "k=1.1\n",

-      "\n",

-      "#Calculations\n",

-      "I_a=T_e/(k*I_f)\n",

-      "N1=1000.0\n",

-      "w_m1=2*math.pi*N1/60\n",

-      "r_a1=.3\n",

-      "V_t1=k*I_f*w_m1+I_a*r_a1\n",

-      "a1=math.degrees(math.acos(V_f*math.pi/(3*V_ml)))\n",

-      "N2=3000\n",

-      "w_m2=2*math.pi*N/60\n",

-      "a2=0\n",

-      "V_t2=3*V_ml*math.cos(math.radians(a))/math.pi\n",

-      "I_f2=(V_t2-I_a*r_a)/(w_m2*k)\n",

-      "V_f2=I_f2*R_f\n",

-      "a2=math.degrees(math.acos(V_f2*math.pi/(3*V_ml)))\n",

-      "\n",

-      "#Results\n",

-      "print(\"firing angle=%.3f deg\" %a)\n",

-      "print(\"firing angle=%.3f deg\" %a)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "firing angle=48.477 deg\n",

-        "firing angle=48.477 deg\n"

-       ]

-      }

-     ],

-     "prompt_number": 12

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.13, Page No 679"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      " #after calculating\n",

-      " #t=w_m/6000-math.pi/360\n",

-      "\n",

-      "N=1000.0\n",

-      "\n",

-      "#Calculations\n",

-      "w_m=2*math.pi*N/60\n",

-      "t=w_m/6000-math.pi/360    \n",

-      "\n",

-      "#Results\n",

-      "print(\"time reqd=%.2f s\" %t)\n",

-      " #printing mistake in the answer in book"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "time reqd=0.01 s\n"

-       ]

-      }

-     ],

-     "prompt_number": 13

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.14, Page No 679"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "I_a=1.0 #supposition\n",

-      "a=60.0\n",

-      "\n",

-      "#Calculations\n",

-      "I_s1=2*math.sqrt(2)/math.pi*I_a*math.sin(math.radians(a))\n",

-      "I_s3=2*math.sqrt(2)/(3*math.pi)*I_a*math.sin(math.radians(3*a))\n",

-      "I_s5=2*math.sqrt(2)/(5*math.pi)*I_a*math.sin(math.radians(5*a))\n",

-      "per3=I_s3/I_s1*100    \n",

-      "print(\"percent of 3rd harmonic current in fundamental=%.2f\" %per3)\n",

-      "per5=I_s5/I_s1*100    \n",

-      "\n",

-      "#Results\n",

-      "print(\"percent of 5th harmonic current in fundamental=%.2f\" %per5)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "percent of 3rd harmonic current in fundamental=0.00\n",

-        "percent of 5th harmonic current in fundamental=-20.00\n"

-       ]

-      }

-     ],

-     "prompt_number": 14

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.15, Page No 680"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "I_a=60.0\n",

-      "I_TA=I_a/3    \n",

-      "\n",

-      "#Calculations\n",

-      "print(\"avg thyristor current=%.0f A\" %I_TA)\n",

-      "I_Tr=I_a/math.sqrt(3)    \n",

-      "print(\"rms thyristor current=%.3f A\" %I_Tr)\n",

-      "V_s=400\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "I_sr=I_a*math.sqrt(2.0/3)\n",

-      "a=150\n",

-      "V_t=3*V_m*math.cos(math.radians(a))/math.pi\n",

-      "pf=V_t*I_a/(math.sqrt(3)*V_s*I_sr)    \n",

-      "print(\"power factor of ac source=%.3f\" %pf)\n",

-      "\n",

-      "r_a=0.5\n",

-      "K_m=2.4\n",

-      "w_m=(V_t-I_a*r_a)/K_m\n",

-      "N=w_m*60/(2*math.pi)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"Speed of motor=%.2f rpm\" %N)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "avg thyristor current=20 A\n",

-        "rms thyristor current=34.641 A\n",

-        "power factor of ac source=-0.827\n",

-        "Speed of motor=-1980.76 rpm\n"

-       ]

-      }

-     ],

-     "prompt_number": 15

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.16, Page No 685"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "I_a=300.0\n",

-      "V_s=600.0\n",

-      "a=0.6\n",

-      "V_t=a*V_s\n",

-      "P=V_t*I_a    \n",

-      "\n",

-      "#Calculations\n",

-      "print(\"input power from source=%.0f kW\" %(P/1000))\n",

-      "R_eq=V_s/(a*I_a)    \n",

-      "print(\"equivalent input resistance=%.3f ohm\" %R_eq)\n",

-      "k=.004\n",

-      "R=.04+.06\n",

-      "w_m=(a*V_s-I_a*R)/(k*I_a)\n",

-      "N=w_m*60/(2*math.pi)    \n",

-      "print(\"motor speed=%.1f rpm\" %N)\n",

-      "T_e=k*I_a**2    \n",

-      "\n",

-      "#Results\n",

-      "print(\"motor torque=%.0f Nm\" %T_e)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "input power from source=108 kW\n",

-        "equivalent input resistance=3.333 ohm\n",

-        "motor speed=2626.1 rpm\n",

-        "motor torque=360 Nm\n"

-       ]

-      }

-     ],

-     "prompt_number": 16

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.17, Page No 686"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "T_on=10.0\n",

-      "T_off=15.0\n",

-      "\n",

-      "#Calculations\n",

-      "a=T_on/(T_on+T_off)\n",

-      "V_s=230.0\n",

-      "V_t=a*V_s\n",

-      "r_a=3\n",

-      "K_m=.5\n",

-      "N=1500\n",

-      "w_m=2*math.pi*N/60\n",

-      "I_a=(V_t-K_m*w_m)/r_a    \n",

-      "\n",

-      "#Results\n",

-      "print(\"motor load current=%.3f A\" %I_a)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "motor load current=4.487 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 17

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.18, Page No 686"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "w_m=0    \n",

-      "print(\"lower limit of speed control=%.0f rpm\" %w_m)\n",

-      "I_a=25.0\n",

-      "r_a=.2\n",

-      "V_s=220\n",

-      "K_m=0.08\n",

-      "\n",

-      "#Calculations\n",

-      "a=(K_m*w_m+I_a*r_a)/V_s    \n",

-      "print(\"lower limit of duty cycle=%.3f\" %a)\n",

-      "a=1    \n",

-      "print(\"upper limit of duty cycle=%.0f\" %a)\n",

-      "w_m=(a*V_s-I_a*r_a)/K_m    \n",

-      "\n",

-      "#Results\n",

-      "print(\"upper limit of speed control=%.1f rpm\" %w_m)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "lower limit of speed control=0 rpm\n",

-        "lower limit of duty cycle=0.023\n",

-        "upper limit of duty cycle=1\n",

-        "upper limit of speed control=2687.5 rpm\n"

-       ]

-      }

-     ],

-     "prompt_number": 18

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.21, Page No 691"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "a=0.6\n",

-      "V_s=400.0\n",

-      "V_t=(1-a)*V_s\n",

-      "I_a=300.0\n",

-      "P=V_t*I_a  \n",

-      "\n",

-      "#Calculations  \n",

-      "print(\"power returned=%.0f kW\" %(P/1000))\n",

-      "r_a=.2\n",

-      "K_m=1.2\n",

-      "R_eq=(1-a)*V_s/I_a+r_a    \n",

-      "print(\"equivalent load resistance=%.4f ohm\" %R_eq)\n",

-      "w_mn=I_a*r_a/K_m\n",

-      "N=w_mn*60/(2*math.pi)    \n",

-      "print(\"min braking speed=%.2f rpm\" %N)\n",

-      "w_mx=(V_s+I_a*r_a)/K_m\n",

-      "N=w_mx*60/(2*math.pi)    \n",

-      "print(\"max braking speed=%.1f rpm\" %N)\n",

-      "w_m=(V_t+I_a*r_a)/K_m\n",

-      "N=w_m*60/(2*math.pi)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"max braking speed=%.1f rpm\" %N)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "power returned=48 kW\n",

-        "equivalent load resistance=0.7333 ohm\n",

-        "min braking speed=477.46 rpm\n",

-        "max braking speed=3660.6 rpm\n",

-        "max braking speed=1750.7 rpm\n"

-       ]

-      }

-     ],

-     "prompt_number": 19

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.22, Page No 699"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "N=1500.0\n",

-      "\n",

-      "#Calculations\n",

-      "print(\"when speed=1455rpm\")\n",

-      "n=1455.0\n",

-      "s1=(N-n)/N\n",

-      "r=math.sqrt(1/3)*(2/3)/(math.sqrt(s1)*(1-s1))    \n",

-      "print(\"I_2mx/I_2r=%.3f\" %r)\n",

-      "print(\"when speed=1350rpm\")\n",

-      "n=1350\n",

-      "s1=(N-n)/N\n",

-      "r=math.sqrt(1/3)*(2/3)/(math.sqrt(s1)*(1-s1))    \n",

-      "\n",

-      "#Results\n",

-      "print(\"I_2mx/I_2r=%.3f\" %r)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "when speed=1455rpm\n",

-        "I_2mx/I_2r=0.000\n",

-        "when speed=1350rpm\n",

-        "I_2mx/I_2r=0.000\n"

-       ]

-      }

-     ],

-     "prompt_number": 20

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.24, Page No 705"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V1=400.0\n",

-      "r1=0.6\n",

-      "r2=0.4\n",

-      "s=1.0\n",

-      "x1=1.6\n",

-      "x2=1.6\n",

-      "\n",

-      "#Calculations\n",

-      "print(\"at starting in normal conditions\")\n",

-      "I_n=V1/math.sqrt((r1+r2/s)**2+(x1+x2)**2)    \n",

-      "print(\"current=%.2f A\" %I_n)\n",

-      "pf=(r1+r2)/math.sqrt((r1+r2/s)**2+(x1+x2)**2)    \n",

-      "print(\"pf=%.4f\" %pf)\n",

-      "f1=50\n",

-      "w_s=4*math.pi*f1/4\n",

-      "T_en=(3/w_s)*I_n**2*(r2/s)    \n",

-      "print(\"\\nTorque developed=%.2f Nm\" %T_en)\n",

-      "print(\"motor is operated with DOL starting\")\n",

-      "I_d=V1/2/math.sqrt((r1+r2/s)**2+((x1+x2)/2)**2)    \n",

-      "print(\"current=%.0f A\" %I_d)\n",

-      "pf=(r1+r2)/math.sqrt((r1+r2/s)**2+((x1+x2)/2)**2)    \n",

-      "print(\"pf=%.2f\" %pf)\n",

-      "f1=25\n",

-      "w_s=4*math.pi*f1/4\n",

-      "T_ed=(3/w_s)*I_d**2*(r2/s)    \n",

-      "print(\"Torque developed=%.3f Nm\" %T_ed)\n",

-      "print(\"at max torque conditions\")\n",

-      "s_mn=r2/math.sqrt((r1)**2+((x1+x2))**2)\n",

-      "I_n=V1/math.sqrt((r1+r2/s_mn)**2+(x1+x2)**2)    \n",

-      "print(\"current=%.3f A\" %I_n)\n",

-      "pf=(r1+r2/s_mn)/math.sqrt((r1+r2/s_mn)**2+(x1+x2)**2)    \n",

-      "print(\"pf=%.4f\" %pf)\n",

-      "f1=50\n",

-      "w_s=4*math.pi*f1/4\n",

-      "T_en=(3/w_s)*I_n**2*(r2/s_mn)    \n",

-      "print(\"Torque developed=%.2f Nm\" %T_en)\n",

-      "print(\"motor is operated with DOL starting\")\n",

-      "s_mn=r2/math.sqrt((r1)**2+((x1+x2)/2)**2)\n",

-      "I_d=V1/2/math.sqrt((r1+r2/s_mn)**2+((x1+x2)/2)**2)    \n",

-      "print(\"current=%.3f A\" %I_d)\n",

-      "pf=(r1+r2/s_mn)/math.sqrt((r1+r2/s_mn)**2+((x1+x2)/2)**2)    \n",

-      "print(\"\\npf=%.3f\" %pf)\n",

-      "f1=25\n",

-      "w_s=4*math.pi*f1/4\n",

-      "T_en=(3/w_s)*I_d**2*(r2/s_mn)  \n",

-      "\n",

-      "\n",

-      "#Results  \n",

-      "print(\"Torque developed=%.3f Nm\" %T_en)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "at starting in normal conditions\n",

-        "current=119.31 A\n",

-        "pf=0.2983\n",

-        "\n",

-        "Torque developed=108.75 Nm\n",

-        "motor is operated with DOL starting\n",

-        "current=106 A\n",

-        "pf=0.53\n",

-        "Torque developed=171.673 Nm\n",

-        "at max torque conditions\n",

-        "current=79.829 A\n",

-        "pf=0.7695\n",

-        "Torque developed=396.26 Nm\n",

-        "motor is operated with DOL starting\n",

-        "current=71.199 A\n",

-        "\n",

-        "pf=0.822\n",

-        "Torque developed=330.883 Nm\n"

-       ]

-      }

-     ],

-     "prompt_number": 21

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.25, Page No 709"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "x1=1.0\n",

-      "X_m=50.0\n",

-      "X_e=x1*X_m/(x1+X_m)\n",

-      "V=231.0\n",

-      "V_e=V*X_m/(x1+X_m)\n",

-      "x2=1.0\n",

-      "r2=.4\n",

-      "r1=0\n",

-      "\n",

-      "#Calculations\n",

-      "s_m=r2/(x2+X_e)    \n",

-      "print(\"slip at max torque=%.2f\" %s_m)\n",

-      "s_mT=r2/(x2+X_m)    \n",

-      "print(\"slip at max torque=%.5f\" %s_mT)\n",

-      "f1=50.0\n",

-      "w_s=4*math.pi*f1/4\n",

-      "print(\"for constant voltage input\")\n",

-      "T_est=(3/w_s)*(V_e/math.sqrt(r2**2+(x2+X_e)**2))**2*(r2)    \n",

-      "print(\"starting torque=%.3f Nm\" %T_est)\n",

-      "T_em=(3/w_s)*V_e**2/(2*(x2+X_e))    \n",

-      "print(\"maximum torque developed=%.2f Nm\" %T_em)\n",

-      "print(\"for constant current input\")\n",

-      "I1=28\n",

-      "T_est=(3/w_s)*(I1*X_m)**2/(r2**2+(x2+X_m)**2)*r2    \n",

-      "print(\"starting torque=%.3f Nm\" %T_est)\n",

-      "T_em=(3/w_s)*(I1*X_m)**2/(2*(x2+X_m))   \n",

-      "print(\"maximum torque developed=%.3f Nm\" %T_em)\n",

-      "s=s_mT\n",

-      "i=1\n",

-      "I_m=I1*(r2/s+i*x2)/(r2/s+i*(x2+X_m))\n",

-      "I_m=math.fabs(I_m)\n",

-      "V1=math.sqrt(3)*I_m*X_m    \n",

-      "\n",

-      "#Results\n",

-      "print(\"supply voltage reqd=%.1f V\" %V1)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "slip at max torque=0.20\n",

-        "slip at max torque=0.00784\n",

-        "for constant voltage input\n",

-        "starting torque=95.988 Nm\n",

-        "maximum torque developed=247.31 Nm\n",

-        "for constant current input\n",

-        "starting torque=5.756 Nm\n",

-        "maximum torque developed=366.993 Nm\n",

-        "supply voltage reqd=1236.2 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 22

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.27, Page No 718"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=420.0\n",

-      "V1=V/math.sqrt(3)\n",

-      "T_e=450.0\n",

-      "N=1440.0\n",

-      "n=1000.0\n",

-      "T_L=T_e*(n/N)**2\n",

-      "n1=1500.0\n",

-      "\n",

-      "#Calculations\n",

-      "w_s=2*math.pi*n1/60\n",

-      "w_m=2*math.pi*n/60\n",

-      "a=.8\n",

-      "I_d=T_L*w_s/(2.339*a*V1)\n",

-      "k=0\n",

-      "R=(1-w_m/w_s)*(2.339*a*V1)/(I_d*(1-k))    \n",

-      "print(\"value of chopper resistance=%.4f ohm\" %R)\n",

-      "n=1320.0\n",

-      "T_L=T_e*(n/N)**2\n",

-      "I_d=T_L*w_s/(2.339*a*V1)    \n",

-      "print(\"Inductor current=%.3f A\" %I_d)\n",

-      "w_m=2*math.pi*n/60\n",

-      "k=1-((1-w_m/w_s)*(2.339*a*V1)/(I_d*R))    \n",

-      "print(\"value of duty cycle=%.4f\" %k)\n",

-      "s=(n1-n)/n1\n",

-      "V_d=2.339*s*a*V1    \n",

-      "print(\"Rectifed o/p voltage=%.3f V\" %V_d)\n",

-      "P=V_d*I_d\n",

-      "I2=math.sqrt(2/3)*I_d\n",

-      "r2=0.02\n",

-      "Pr=3*I2**2*r2\n",

-      "I1=a*I2\n",

-      "r1=0.015\n",

-      "Ps=3*I1**2*r1\n",

-      "Po=T_L*w_m\n",

-      "Pi=Po+Ps+Pr+P\n",

-      "eff=Po/Pi*100   \n",

-      "\n",

-      "#Results\n",

-      "print(\"Efficiency(in percent)=%.2f\" %eff)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "value of chopper resistance=2.0132 ohm\n",

-        "Inductor current=130.902 A\n",

-        "value of duty cycle=0.7934\n",

-        "Rectifed o/p voltage=54.449 V\n",

-        "Efficiency(in percent)=88.00\n"

-       ]

-      }

-     ],

-     "prompt_number": 23

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.28, Page No 720"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=400.0\n",

-      "V_ph=V/math.sqrt(3)\n",

-      "N_s=1000.0\n",

-      "N=800.0\n",

-      "a=.7\n",

-      "I_d=110\n",

-      "R=2.0\n",

-      "\n",

-      "#Calculations\n",

-      "k=1-((1-N/N_s)*(2.339*a*V_ph)/(I_d*R))    \n",

-      "print(\"value of duty cycle=%.3f\" %k)\n",

-      "P=I_d**2*R*(1-k)\n",

-      "I1=a*I_d*math.sqrt(2/3)\n",

-      "r1=0.1\n",

-      "r2=0.08\n",

-      "Pr=3*I1**2*(r1+r2)\n",

-      "P_o=20000\n",

-      "P_i=P_o+Pr+P\n",

-      "eff=P_o/P_i*100    \n",

-      "print(\"Efficiency=%.2f\" %eff)\n",

-      "I11=math.sqrt(6)/math.pi*a*I_d\n",

-      "th=43\n",

-      "P_ip=math.sqrt(3)*V*I11*math.cos(math.radians(th))\n",

-      "pf=P_ip/(math.sqrt(3)*V*I11)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"Input power factor=%.4f\" %pf)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "value of duty cycle=0.656\n",

-        "Efficiency=70.62\n",

-        "Input power factor=0.7314\n"

-       ]

-      }

-     ],

-     "prompt_number": 24

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.29, Page No 724"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=420.0\n",

-      "V1=V/math.sqrt(3)\n",

-      "N=1000.0\n",

-      "w_m=2*math.pi*N/60\n",

-      "N_s=1500.0\n",

-      "\n",

-      "#Calculations\n",

-      "s=(N_s-N)/N_s\n",

-      "a=0.8\n",

-      "V_d=2.339*a*s*V1    \n",

-      "print(\"rectified voltage=%.2f V\" %V_d)\n",

-      "T=450.0\n",

-      "N1=1200.0\n",

-      "T_L=T*(N/N1)**2\n",

-      "f1=50\n",

-      "w_s=4*math.pi*f1/4\n",

-      "I_d=w_s*T_L/(2.339*a*V1)    \n",

-      "print(\"inductor current=%.2f A\" %I_d)\n",

-      "a_T=-.4\n",

-      "a1=math.degrees(math.acos(s*a/a_T))\n",

-      "print(\"delay angle of inverter=%.2f deg\" %a1)\n",

-      "\n",

-      "P_s=V_d*I_d\n",

-      "P_o=T_L*w_m\n",

-      "R_d=0.01\n",

-      "P_i=I_d**2*R_d\n",

-      "I2=math.sqrt(2/3)*I_d\n",

-      "r2=0.02\n",

-      "r1=0.015\n",

-      "P_rol=3*I2**2*r2\n",

-      "I1=a*I2\n",

-      "P_sol=3*I1**2*r1\n",

-      "P_i=P_o+P_rol+P_sol+P_i\n",

-      "eff=P_o/P_i*100    \n",

-      "print(\"\\nefficiency=%.2f\" %eff)\n",

-      "w_m=w_s*(1+(-a_T/a)*math.cos(math.radians(a1))-w_s*R_d*T_L/(2.339*a*V1)**2)\n",

-      "N=w_m*60/(2*math.pi) \n",

-      "\n",

-      "#Results   \n",

-      "print(\"motor speed=%.1f rpm\" %N)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rectified voltage=151.25 V\n",

-        "inductor current=108.18 A\n",

-        "delay angle of inverter=131.81 deg\n",

-        "\n",

-        "efficiency=99.64\n",

-        "motor speed=996.4 rpm\n"

-       ]

-      }

-     ],

-     "prompt_number": 25

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.30, Page No 726"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=700.0\n",

-      "E2=V/math.sqrt(3)\n",

-      "N_s=1500.0\n",

-      "N=1200.0\n",

-      "\n",

-      "#Calculations\n",

-      "s=(N_s-N)/N_s\n",

-      "V_dd=0.7\n",

-      "V_dt=1.5\n",

-      "V_d=3*math.sqrt(6)*s*E2/math.pi-2*V_dd\n",

-      "V1=415.0\n",

-      "a=math.degrees(math.acos((3*math.sqrt(2)*E2/math.pi)**-1*(-V_d+2*V_dt)))\n",

-      "\n",

-      "#Results\n",

-      "print(\"firing angle advance=%.2f deg\" %(180-a))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "firing angle advance=70.22 deg\n"

-       ]

-      }

-     ],

-     "prompt_number": 26

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.31, Page No 726"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=700.0\n",

-      "E2=V/math.sqrt(3)\n",

-      "N_s=1500.0\n",

-      "N=1200.0\n",

-      "\n",

-      "#Calculations\n",

-      "s=(N_s-N)/N_s\n",

-      "V_dd=.7\n",

-      "V_dt=1.5\n",

-      "a=0\n",

-      "u=18 #overlap angle in case of rectifier\n",

-      "V_d=3*math.sqrt(6)*s*E2*(math.cos(math.radians(a))+math.cos(math.radians(a+u)))/(2*math.pi)-2*V_dd\n",

-      "V1=415\n",

-      "V_ml=math.sqrt(2)*V1\n",

-      "u=4 #overlap anglein the inverter\n",

-      " #V_dc=-(3*V_ml*(math.cos(math.radians(a))+math.cos(math.radians(a+u)))/(2*math.pi)-2*V_dt)\n",

-      " #V_dc=V_d\n",

-      " #after solving %  (1+math.cos(math.radians(u)))*math.cos(math.radians(a))-math.sin(math.radians(u))*math.sin(math.radians(a))=-.6425\n",

-      "a=math.degrees(math.acos(-.6425/(math.sqrt((1+math.cos(math.radians(u)))**2+math.sin(math.radians(u))**2))))-math.degrees(math.asin(math.sin(math.radians(a))/(1+math.cos(math.radians(u)))))\n",

-      "\n",

-      "#Results\n",

-      "print(\"firing angle advance=%.2f deg\" %(180-a))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "firing angle advance=71.25 deg\n"

-       ]

-      }

-     ],

-     "prompt_number": 27

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.32, Page No 727"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=700.0\n",

-      "E2=V\n",

-      "N_s=1500.0\n",

-      "N=1200.0\n",

-      "\n",

-      "#Calculations\n",

-      "s=(N_s-N)/N_s\n",

-      "V1=415.0\n",

-      "a_T=s*E2/V1    \n",

-      "\n",

-      "#Results\n",

-      "print(\"voltage ratio of the transformer=%.2f\" %a_T)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "voltage ratio of the transformer=0.34\n"

-       ]

-      }

-     ],

-     "prompt_number": 28

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.33, Page No 733"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "P=6.0\n",

-      "N_s=600.0\n",

-      "f1=P*N_s/120.0\n",

-      "V=400.0\n",

-      "f=50.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_t=f1*V/f    \n",

-      "print(\"supply freq=%.0f Hz\" %V_t)\n",

-      "T=340.0\n",

-      "N=1000.0\n",

-      "T_L=T*(N_s/N)**2\n",

-      "w_s=2*math.pi*N_s/60\n",

-      "P=T_L*w_s\n",

-      "I_a=P/(math.sqrt(3)*V_t)    \n",

-      "print(\"armature current=%.2f A\" %I_a)\n",

-      "Z_s=2\n",

-      "X_s=f1/f*math.fabs(Z_s)\n",

-      "V_t=V_t/math.sqrt(3)\n",

-      "Ef=math.sqrt(V_t**2+(I_a*X_s)**2)\n",

-      "print(\"excitation voltage=%.2f V\" %(math.sqrt(3)*Ef))\n",

-      "dl=math.degrees(math.atan(I_a*X_s/V_t))\n",

-      "print(\"load angle=%.2f deg\" %dl)\n",

-      "T_em=(3/w_s)*(Ef*V_t/X_s)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"pull out torque=%.2f Nm\" %T_em)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "supply freq=240 Hz\n",

-        "armature current=18.50 A\n",

-        "excitation voltage=243.06 V\n",

-        "load angle=9.10 deg\n",

-        "pull out torque=773.69 Nm\n"

-       ]

-      }

-     ],

-     "prompt_number": 29

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.34, Page No 736"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "P=4.0\n",

-      "f=50.0\n",

-      "w_s=4*math.pi*f/P\n",

-      "X_d=8.0\n",

-      "X_q=2.0\n",

-      "T_e=80.0\n",

-      "V=400.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_t=V/math.sqrt(3)\n",

-      "dl=(1/2)*math.degrees(math.asin(T_e*w_s/((3/2)*(V_t)**2*(1/X_q-1/X_d))))    \n",

-      "print(\"load angle=%.3f deg\" %dl)\n",

-      "I_d=V_t*math.cos(math.radians(dl))/X_d\n",

-      "I_q=V_t*math.sin(math.radians(dl))/X_q\n",

-      "I_a=math.sqrt(I_d**2+I_q**2)    \n",

-      "print(\"armature current=%.2f A\" %I_a)\n",

-      "pf=T_e*w_s/(math.sqrt(3)*V*I_a)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"input power factor=%.4f\" %pf)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "load angle=0.000 deg\n",

-        "armature current=28.87 A\n",

-        "input power factor=0.6283\n"

-       ]

-      }

-     ],

-     "prompt_number": 30

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.35, Page No 737"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "T_e=3.0\n",

-      "K_m=1.2\n",

-      "I_a=T_e/K_m\n",

-      "r_a=2.0\n",

-      "V=230.0\n",

-      "\n",

-      "#Calculations\n",

-      "E_a=(0.263*math.sqrt(2)*V-I_a*r_a)/(1-55/180)\n",

-      "w_m=E_a/K_m\n",

-      "N=w_m*60/(2*math.pi)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"motor speed=%.2f rpm\" %N)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "motor speed=640.96 rpm\n"

-       ]

-      }

-     ],

-     "prompt_number": 31

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.36, Page No 738"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "K_m=1.0\n",

-      "N=1360.0\n",

-      "\n",

-      "#Calculations\n",

-      "w_m=2*math.pi*N/60\n",

-      "E_a=K_m*w_m\n",

-      " #after calculations V_t % calculated\n",

-      "V_t=163.45\n",

-      "r_a=4\n",

-      "I_a=(V_t-E_a)/r_a\n",

-      "T_e=K_m*I_a    \n",

-      "\n",

-      "#Results\n",

-      "print(\"motor torque=%.4f Nm\" %T_e)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "motor torque=5.2578 Nm\n"

-       ]

-      }

-     ],

-     "prompt_number": 32

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.37, Page No 740"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "K_m=1.0\n",

-      "N=2100.0\n",

-      "\n",

-      "#Calculations\n",

-      "w_m=2*math.pi*N/60\n",

-      "E_a=K_m*w_m\n",

-      " #after calculations V_t % calculated\n",

-      "V_t=227.66\n",

-      "r_a=4\n",

-      "I_a=(V_t-E_a)/r_a\n",

-      "T_e=K_m*I_a    \n",

-      "\n",

-      "#Results\n",

-      "print(\"motor torque=%.2f Nm\" %T_e)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "motor torque=1.94 Nm\n"

-       ]

-      }

-     ],

-     "prompt_number": 33

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.38, Page No 742"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "K_m=1.0\n",

-      "N=840.0\n",

-      "\n",

-      "#Calculations\n",

-      "w_m=2*math.pi*N/60\n",

-      "E_a=K_m*w_m\n",

-      "V=230.0\n",

-      "a=75.0\n",

-      "V_t=math.sqrt(2)*V/math.pi*(1+math.cos(math.radians(a)))\n",

-      "r_a=4\n",

-      "I_a=(V_t-E_a)/r_a\n",

-      "T_e=K_m*I_a    \n",

-      "\n",

-      "#Results\n",

-      "print(\"motor torque=%.4f Nm\" %T_e)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits.\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "motor torque=10.5922 Nm\n"

-       ]

-      }

-     ],

-     "prompt_number": 34

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.39, Page No 743"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "K_m=1.0\n",

-      "N=1400.0\n",

-      "\n",

-      "#Calculations\n",

-      "w_m=2*math.pi*N/60\n",

-      "E_a=K_m*w_m\n",

-      "V=230.0\n",

-      "a=60.0\n",

-      "a1=212\n",

-      "V_t=math.sqrt(2)*V/math.pi*(math.cos(math.radians(a))-math.cos(math.radians(a1)))+E_a*(180+a-a1)/180\n",

-      "r_a=3\n",

-      "I_a=(V_t-E_a)/r_a\n",

-      "T_e=K_m*I_a   \n",

-      "\n",

-      "#Results\n",

-      "print(\"motor torque=%.3f Nm\" %T_e)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "motor torque=5.257 Nm\n"

-       ]

-      }

-     ],

-     "prompt_number": 35

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.40, Page No 745"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "K_m=1.0\n",

-      "N=600.0\n",

-      "w_m=2*math.pi*N/60\n",

-      "E_a=K_m*w_m\n",

-      "V=230.0\n",

-      "a=60.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_t=2*math.sqrt(2)*V/math.pi*(math.cos(math.radians(a)))\n",

-      "r_a=3\n",

-      "I_a=(V_t-E_a)/r_a\n",

-      "T_e=K_m*I_a    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"motor torque=%.3f Nm\" %T_e)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "motor torque=13.568 Nm\n"

-       ]

-      }

-     ],

-     "prompt_number": 36

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.41, Page No 745"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "r1=.6\n",

-      "r2=.4\n",

-      "s=0.04\n",

-      "x1=1.6\n",

-      "x2=1.6\n",

-      "Z=(r1+r2/s)+(x1+x2)\n",

-      "V=400.0\n",

-      "I1=V/Z    \n",

-      "print(\"source current=%.3f A \" %math.degrees(math.atan(I1.imag/I1.real)))\n",

-      "print(\"and with %.1f deg phase\" %math.fabs(I1))\n",

-      "I2=V/Z\n",

-      "N=1500\n",

-      "w_s=2*math.pi*N/60\n",

-      "T_e=(3/w_s)*abs(I2)**2*r2/s    \n",

-      "print(\"motor torque=%.2f Nm\" %T_e)\n",

-      "N_r=N*(1-s)\n",

-      "\n",

-      "f=45\n",

-      "N_s1=120*f/4\n",

-      "w_s=2*math.pi*N_s1/60\n",

-      "s1=(N_s1-N_r)/N_s1\n",

-      "Z=(r1+r2/s1)+(x1+x2)*f/50.0\n",

-      "V=360\n",

-      "I1=V/Z    \n",

-      "print(\"source current=%.3f A \" %math.degrees(math.atan(I1.imag/I1.real)))\n",

-      "print(\"and with %.1f deg phase\" %math.fabs(I1))\n",

-      "I2=V/Z\n",

-      "T_e=(3/w_s)*abs(I2)**2*r2/s1    \n",

-      "print(\"motor torque=%.2f Nm\" %T_e)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "source current=0.000 A \n",

-        "and with 29.0 deg phase\n",

-        "motor torque=160.46 Nm\n",

-        "source current=-0.000 A \n",

-        "and with 142.9 deg phase\n",

-        "motor torque=-2598.45 Nm\n"

-       ]

-      }

-     ],

-     "prompt_number": 37

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Power_Electronics/Chapter12_3.ipynb b/_Power_Electronics/Chapter12_3.ipynb
deleted file mode 100755
index f8605d69..00000000
--- a/_Power_Electronics/Chapter12_3.ipynb
+++ /dev/null
@@ -1,1997 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 12 : Electic Drives"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.1, Page No 658"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "T_e=15.0 #Nm\n",

-      "K_m=0.5 #V-s/rad\n",

-      "I_a=T_e/K_m\n",

-      "n_m=1000.0\n",

-      "\n",

-      "#Calculations\n",

-      "w_m=2*math.pi*n_m/60\n",

-      "E_a=K_m*w_m\n",

-      "r_a=0.7\n",

-      "V_t=E_a+I_a*r_a\n",

-      "V_s=230.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "a=math.degrees(math.acos(2*math.pi*V_t/V_m-1))\n",

-      "print(\"firing angle delay=%.3f deg\" %a)\n",

-      "I_Tr=I_a*math.sqrt((180-a)/360)    \n",

-      "print(\"rms value of thyristor current=%.3f A\" %I_Tr)\n",

-      "I_fdr=I_a*math.sqrt((180+a)/360)    \n",

-      "print(\"rms value of freewheeling diode current=%.3f A\" %I_fdr)\n",

-      "pf=V_t*I_a/(V_s*I_Tr)  \n",

-      "\n",

-      "#Results  \n",

-      "print(\"input power factor=%.4f\" %pf)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "firing angle delay=65.349 deg\n",

-        "rms value of thyristor current=16.930 A\n",

-        "rms value of freewheeling diode current=24.766 A\n",

-        "input power factor=0.5652\n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.2, Page No 660"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=230.0\n",

-      "E=150.0\n",

-      "R=8.0\n",

-      "\n",

-      "#Calculations\n",

-      "th1=math.sin(math.radians(E/(math.sqrt(2)*V)))\n",

-      "I_o=(1/(2*math.pi*R))*(2*math.sqrt(2)*230*math.cos(math.radians(th1))-E*(math.pi-2*th1*math.pi/180))    \n",

-      "P=E*I_o    \n",

-      "I_or=math.sqrt((1/(2*math.pi*R**2))*((V**2+E**2)*(math.pi-2*th1*math.pi/180)+V**2*math.sin(math.radians(2*th1))-4*math.sqrt(2)*V*E*math.cos(math.radians(th1))))\n",

-      "P_r=I_or**2*R    \n",

-      "pf=(P+P_r)/(V*I_or)\n",

-      "\n",

-      "#Results\n",

-      "print(\"avg charging curent=%.4f A\" %I_o)\n",

-      "print(\"power supplied to the battery=%.2f W\" %P)\n",

-      "print(\"power dissipated by the resistor=%.3f W\" %P_r)    \n",

-      "print(\"supply pf=%.3f\" %pf)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "avg charging curent=3.5679 A\n",

-        "power supplied to the battery=535.18 W\n",

-        "power dissipated by the resistor=829.760 W\n",

-        "supply pf=0.583\n"

-       ]

-      }

-     ],

-     "prompt_number": 2

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.3 Page No 661"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variablesV_s=250\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "a=30.0\n",

-      "k=0.03 #Nm/A**2\n",

-      "n_m=1000.0\n",

-      "\n",

-      "#Calculations\n",

-      "w_m=2*math.pi*n_m/60\n",

-      "r=.2 #r_a+r_s\n",

-      "V_t=V_m/math.pi*(1+math.cos(math.radians(a)))\n",

-      "I_a=V_t/(k*w_m+r)   \n",

-      "print(\"motor armature current=%.2f A\" %I_a)\n",

-      "T_e=k*I_a**2    \n",

-      "print(\"motor torque=%.3f Nm\" %T_e)\n",

-      "I_sr=I_a*math.sqrt((180-a)/180)\n",

-      "pf=(V_t*I_a)/(V_s*I_sr)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"input power factor=%.2f\" %pf)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "motor armature current=57.82 A\n",

-        "motor torque=100.285 Nm\n",

-        "input power factor=0.92\n"

-       ]

-      }

-     ],

-     "prompt_number": 3

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.4, Page No 663"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=400.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "V_f=2*V_m/math.pi\n",

-      "r_f=200.0\n",

-      "I_f=V_f/r_f\n",

-      "T_e=85.0\n",

-      "K_a=0.8\n",

-      "\n",

-      "#Calculations\n",

-      "I_a=T_e/(I_f*K_a)    \n",

-      "print(\"rated armature current=%.2f A\" %I_a)\n",

-      "n_m=1200.0\n",

-      "w_m=2*math.pi*n_m/60\n",

-      "r_a=0.2\n",

-      "V_t=K_a*I_f*w_m+I_a*r_a\n",

-      "a=math.degrees(math.acos(V_t*math.pi/(2*V_m)))\n",

-      "print(\"firing angle delay=%.2f deg\" %a)\n",

-      "E_a=V_t\n",

-      "w_mo=E_a/(K_a*I_f)\n",

-      "N=60*w_mo/(2*math.pi)\n",

-      "reg=((N-n_m)/n_m)*100    \n",

-      "print(\"speed regulation at full load=%.2f\" %reg)\n",

-      "I_ar=I_a\n",

-      "pf=(V_t*I_a)/(V_s*I_ar)    \n",

-      "print(\"input power factor of armature convertor=%.4f\" %pf)\n",

-      "I_fr=I_f\n",

-      "I_sr=math.sqrt(I_fr**2+I_ar**2)\n",

-      "VA=I_sr*V_s\n",

-      "P=V_t*I_a+V_f*I_f\n",

-      "\n",

-      "#Results\n",

-      "print(\"input power factor of drive=%.4f\" %(P/VA))\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rated armature current=59.01 A\n",

-        "firing angle delay=57.63 deg\n",

-        "speed regulation at full load=6.52\n",

-        "input power factor of armature convertor=0.4821\n",

-        "input power factor of drive=0.5093\n"

-       ]

-      }

-     ],

-     "prompt_number": 4

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.5 Page No 664"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=400.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "V_f=2*V_m/math.pi\n",

-      "\n",

-      "#Calculations\n",

-      "a1=math.degrees(math.acos(V_t*math.pi/(2*V_m))) \n",

-      "print(\"delay angle of field converter=%.0f deg\" %a1)\n",

-      "r_f=200.0\n",

-      "I_f=V_f/r_f\n",

-      "T_e=85.0\n",

-      "K_a=0.8\n",

-      "I_a=T_e/(I_f*K_a)\n",

-      "n_m=1200.0\n",

-      "w_m=2*math.pi*n_m/60\n",

-      "r_a=0.1\n",

-      "I_a=50.0\n",

-      "V_t=-K_a*I_f*w_m+I_a*r_a\n",

-      "a=math.degrees(math.acos(V_t*math.pi/(2*V_m)))\n",

-      "\n",

-      "#Results\n",

-      "print(\"firing angle delay of armature converter=%.3f deg\" %a)\n",

-      "print(\"power fed back to ac supply=%.0f W\" %(-V_t*I_a))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "delay angle of field converter=58 deg\n",

-        "firing angle delay of armature converter=119.260 deg\n",

-        "power fed back to ac supply=8801 W\n"

-       ]

-      }

-     ],

-     "prompt_number": 5

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.6 Page No 665"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_t=220.0\n",

-      "n_m=1500.0\n",

-      "w_m=2*math.pi*n_m/60\n",

-      "I_a=10.0\n",

-      "r_a=1.0\n",

-      "\n",

-      "#Calculations\n",

-      "K_m=(V_t-I_a*r_a)/(w_m)\n",

-      "T=5.0\n",

-      "I_a=T/K_m\n",

-      "V_s=230.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "a=30.0\n",

-      "V_t=2*V_m*math.cos(math.radians(a))/math.pi\n",

-      "w_m=(V_t-I_a*r_a)/K_m\n",

-      "N=w_m*60/(2*math.pi)    \n",

-      "\n",

-      "print(\"motor speed=%.2f rpm\" %N)\n",

-      "a=45\n",

-      "n_m=1000\n",

-      "w_m=2*math.pi*n_m/60\n",

-      "V_t=2*V_m*math.cos(math.radians(a))/math.pi\n",

-      "I_a=(V_t-K_m*w_m)/r_a\n",

-      "T_e=K_m*I_a    \n",

-      "\n",

-      "#Results\n",

-      "print(\"torque developed=%.3f Nm\" %T_e)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "motor speed=1254.22 rpm\n",

-        "torque developed=8.586 Nm\n"

-       ]

-      }

-     ],

-     "prompt_number": 6

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.7, Page No 666"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_t=220.0\n",

-      "n_m=1000.0\n",

-      "w_m=2*math.pi*n_m/60\n",

-      "I_a=60.0\n",

-      "r_a=.1\n",

-      "\n",

-      "#Calculations\n",

-      "K_m=(V_t-I_a*r_a)/(w_m)\n",

-      "V_s=230\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "print(\"for 600rpm speed\")\n",

-      "n_m=600.0\n",

-      "w_m=2*math.pi*n_m/60\n",

-      "a=math.degrees(math.acos((K_m*w_m+I_a*r_a)*math.pi/(2*V_m))) \n",

-      "print(\"firing angle=%.3f deg\" %a)\n",

-      "print(\"for -500rpm speed\")\n",

-      "n_m=-500.0\n",

-      "w_m=2*math.pi*n_m/60\n",

-      "a=math.degrees(math.acos((K_m*w_m+I_a*r_a)*math.pi/(2*V_m)))\n",

-      "print(\"firing angle=%.2f deg\" %a)\n",

-      "I_a=I_a/2\n",

-      "a=150\n",

-      "V_t=2*V_m*math.cos(math.radians(a))/math.pi\n",

-      "w_m=(V_t-I_a*r_a)/K_m\n",

-      "N=w_m*60/(2*math.pi)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"motor speed=%.3f rpm\" %N)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for 600rpm speed\n",

-        "firing angle=49.530 deg\n",

-        "for -500rpm speed\n",

-        "firing angle=119.19 deg\n",

-        "motor speed=-852.011 rpm\n"

-       ]

-      }

-     ],

-     "prompt_number": 7

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.8 Page No 672"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "K_m=1.5\n",

-      "T_e=50.0\n",

-      "I_a=T_e/K_m\n",

-      "r_a=0.9\n",

-      "a=45.0\n",

-      "V_s=415.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_ml=math.sqrt(2)*V_s\n",

-      "w_m=((3*V_ml*(1+math.cos(math.radians(a)))/(2*math.pi))-I_a*r_a)/K_m\n",

-      "N=w_m*60/(2*math.pi)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"motor speed=%.2f rpm\" %N)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "motor speed=2854.42 rpm\n"

-       ]

-      }

-     ],

-     "prompt_number": 8

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.9 Page No 672"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variablesV_t=600\n",

-      "n_m=1500.0\n",

-      "w_m=2*math.pi*n_m/60\n",

-      "I_a=80.0\n",

-      "r_a=1.0\n",

-      "\n",

-      "#Calculations\n",

-      "K_m=(V_t-I_a*r_a)/(w_m)\n",

-      "V_s=400.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "print(\"for firing angle=45deg and speed=1200rpm\")\n",

-      "a=45.0\n",

-      "n_m=1200.0\n",

-      "w_m=2*math.pi*n_m/60\n",

-      "I_a=(3*V_m*(1+math.cos(math.radians(a)))/(2*math.pi)-K_m*w_m)/r_a\n",

-      "I_sr=I_a*math.sqrt(2/3)    \n",

-      "print(\"rms value of source current=%.3f A\" %I_sr)\n",

-      "print(\"rms value of thyristor current=%.3f A\" %(I_a*math.sqrt(1/3)))\n",

-      "print(\"avg value of thyristor current=%.2f A\" %I_a*(1/3))\n",

-      "pf=(3/(2*math.pi)*(1+math.cos(math.radians(a))))    \n",

-      "print(\"input power factor=%.3f\" %pf)\n",

-      "\n",

-      "print(\"for firing angle=90deg and speed=700rpm\")\n",

-      "a=90\n",

-      "n_m=700\n",

-      "w_m=2*math.pi*n_m/60\n",

-      "I_a=(3*V_m*(1+math.cos(math.radians(a)))/(2*math.pi)-K_m*w_m)/r_a\n",

-      "I_sr=I_a*math.sqrt(90/180)    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"rms value of source current=%.3f A\" %I_sr)\n",

-      "print(\"rms value of thyristor current=%.3f A\" %(I_a*math.sqrt(90.0/360)))\n",

-      "print(\"avg value of thyristor current=%.3f A\" %I_a*(1/3))\n",

-      "pf=(math.sqrt(6)/(2*math.pi)*(1+math.cos(math.radians(a))))*math.sqrt(180/(180-a))    \n",

-      "print(\"input power factor=%.4f\" %pf)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for firing angle=45deg and speed=1200rpm\n",

-        "rms value of source current=0.000 A\n",

-        "rms value of thyristor current=0.000 A\n",

-        "\n",

-        "input power factor=0.815\n",

-        "for firing angle=90deg and speed=700rpm\n",

-        "rms value of source current=0.000 A\n",

-        "rms value of thyristor current=195.558 A\n",

-        "\n",

-        "input power factor=0.5513\n"

-       ]

-      }

-     ],

-     "prompt_number": 9

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.10 Page No 676"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=400.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "a=30\n",

-      "V_t=3*V_m*math.cos(math.radians(a))/math.pi\n",

-      "I_a=21.0\n",

-      "r_a=.1\n",

-      "V_d=2.0\n",

-      "K_m=1.6\n",

-      "\n",

-      "#Calculations\n",

-      "w_m=(V_t-I_a*r_a-V_d)/K_m\n",

-      "N=w_m*60/(2*math.pi)    \n",

-      "print(\"speed of motor=%.1f rpm\" %N)\n",

-      "\n",

-      "N=2000\n",

-      "w_m=2*math.pi*N/60\n",

-      "I_a=210\n",

-      "V_t=K_m*w_m+I_a*r_a+V_d\n",

-      "a=math.degrees(math.acos(V_t*math.pi/(3*V_m)))\n",

-      "print(\"firing angle=%.2f deg\" %a)\n",

-      "I_sr=I_a*math.sqrt(2.0/3.0)\n",

-      "pf=V_t*I_a/(math.sqrt(3)*V_s*I_sr)    \n",

-      "print(\"supply power factor=%.3f\" %pf)\n",

-      "\n",

-      "I_a=21\n",

-      "w_m=(V_t-I_a*r_a-V_d)/K_m\n",

-      "n=w_m*60/(2*math.pi)\n",

-      "reg=(n-N)/N*100    \n",

-      "\n",

-      "#Results\n",

-      "print(\"speed regulation(percent)=%.2f\" %reg)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "speed of motor=2767.6 rpm\n",

-        "firing angle=48.48 deg\n",

-        "supply power factor=0.633\n",

-        "speed regulation(percent)=5.64\n"

-       ]

-      }

-     ],

-     "prompt_number": 10

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.11, Page No 677"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_t=230.0\n",

-      "V_l=V_t*math.pi/(3*math.sqrt(2))\n",

-      "V_ph=V_l/math.sqrt(3)\n",

-      "V_in=400     #per phase voltage input\n",

-      "\n",

-      "#Calculations\n",

-      "N1=1500.0\n",

-      "I_a1=20.0\n",

-      "r_a1=.6\n",

-      "E_a1=V_t-I_a1*r_a1\n",

-      "n1=1000.0\n",

-      "E_a2=E_a1/1500.0*1000.0\n",

-      "V_t1=E_a1+I_a1*r_a1\n",

-      "a1=math.degrees(math.acos(V_t1*math.pi/(3*math.sqrt(2.0)*V_l)))\n",

-      "I_a2=.5*I_a1\n",

-      "n2=-900.0\n",

-      "V_t2=n2*E_a2/N1+I_a2*r_a1\n",

-      "a2=math.degrees(math.acos(V_t2*math.pi/(3*math.sqrt(2)*V_l))) \n",

-      "\n",

-      "#Results\n",

-      "print(\"transformer phase turns ratio=%.3f\" %(V_in/V_ph))\n",

-      "print(\"for motor running at 1000rpm at rated torque\")\n",

-      "print(\"firing angle delay=%.2f deg\" %a1)\n",

-      "print(\"for motor running at -900rpm at half of rated torque\")\n",

-      "print(\"firing angle delay=%.3f deg\" %a2)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "transformer phase turns ratio=4.068\n",

-        "for motor running at 1000rpm at rated torque\n",

-        "firing angle delay=0.00 deg\n",

-        "for motor running at -900rpm at half of rated torque\n",

-        "firing angle delay=110.674 deg\n"

-       ]

-      }

-     ],

-     "prompt_number": 11

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.12, Page No 678"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variablesV_s=400\n",

-      "V_ml=math.sqrt(2)*V_s\n",

-      "V_f=3*V_ml/math.pi\n",

-      "R_f=300.0\n",

-      "I_f=V_f/R_f\n",

-      "T_e=60.0\n",

-      "k=1.1\n",

-      "\n",

-      "#Calculations\n",

-      "I_a=T_e/(k*I_f)\n",

-      "N1=1000.0\n",

-      "w_m1=2*math.pi*N1/60\n",

-      "r_a1=.3\n",

-      "V_t1=k*I_f*w_m1+I_a*r_a1\n",

-      "a1=math.degrees(math.acos(V_f*math.pi/(3*V_ml)))\n",

-      "N2=3000\n",

-      "w_m2=2*math.pi*N/60\n",

-      "a2=0\n",

-      "V_t2=3*V_ml*math.cos(math.radians(a))/math.pi\n",

-      "I_f2=(V_t2-I_a*r_a)/(w_m2*k)\n",

-      "V_f2=I_f2*R_f\n",

-      "a2=math.degrees(math.acos(V_f2*math.pi/(3*V_ml)))\n",

-      "\n",

-      "#Results\n",

-      "print(\"firing angle=%.3f deg\" %a)\n",

-      "print(\"firing angle=%.3f deg\" %a)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "firing angle=48.477 deg\n",

-        "firing angle=48.477 deg\n"

-       ]

-      }

-     ],

-     "prompt_number": 12

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.13, Page No 679"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      " #after calculating\n",

-      " #t=w_m/6000-math.pi/360\n",

-      "\n",

-      "N=1000.0\n",

-      "\n",

-      "#Calculations\n",

-      "w_m=2*math.pi*N/60\n",

-      "t=w_m/6000-math.pi/360    \n",

-      "\n",

-      "#Results\n",

-      "print(\"time reqd=%.2f s\" %t)\n",

-      " #printing mistake in the answer in book"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "time reqd=0.01 s\n"

-       ]

-      }

-     ],

-     "prompt_number": 13

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.14, Page No 679"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "I_a=1.0 #supposition\n",

-      "a=60.0\n",

-      "\n",

-      "#Calculations\n",

-      "I_s1=2*math.sqrt(2)/math.pi*I_a*math.sin(math.radians(a))\n",

-      "I_s3=2*math.sqrt(2)/(3*math.pi)*I_a*math.sin(math.radians(3*a))\n",

-      "I_s5=2*math.sqrt(2)/(5*math.pi)*I_a*math.sin(math.radians(5*a))\n",

-      "per3=I_s3/I_s1*100    \n",

-      "print(\"percent of 3rd harmonic current in fundamental=%.2f\" %per3)\n",

-      "per5=I_s5/I_s1*100    \n",

-      "\n",

-      "#Results\n",

-      "print(\"percent of 5th harmonic current in fundamental=%.2f\" %per5)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "percent of 3rd harmonic current in fundamental=0.00\n",

-        "percent of 5th harmonic current in fundamental=-20.00\n"

-       ]

-      }

-     ],

-     "prompt_number": 14

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.15, Page No 680"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "I_a=60.0\n",

-      "I_TA=I_a/3    \n",

-      "\n",

-      "#Calculations\n",

-      "print(\"avg thyristor current=%.0f A\" %I_TA)\n",

-      "I_Tr=I_a/math.sqrt(3)    \n",

-      "print(\"rms thyristor current=%.3f A\" %I_Tr)\n",

-      "V_s=400\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "I_sr=I_a*math.sqrt(2.0/3)\n",

-      "a=150\n",

-      "V_t=3*V_m*math.cos(math.radians(a))/math.pi\n",

-      "pf=V_t*I_a/(math.sqrt(3)*V_s*I_sr)    \n",

-      "print(\"power factor of ac source=%.3f\" %pf)\n",

-      "\n",

-      "r_a=0.5\n",

-      "K_m=2.4\n",

-      "w_m=(V_t-I_a*r_a)/K_m\n",

-      "N=w_m*60/(2*math.pi)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"Speed of motor=%.2f rpm\" %N)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "avg thyristor current=20 A\n",

-        "rms thyristor current=34.641 A\n",

-        "power factor of ac source=-0.827\n",

-        "Speed of motor=-1980.76 rpm\n"

-       ]

-      }

-     ],

-     "prompt_number": 15

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.16, Page No 685"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "I_a=300.0\n",

-      "V_s=600.0\n",

-      "a=0.6\n",

-      "V_t=a*V_s\n",

-      "P=V_t*I_a    \n",

-      "\n",

-      "#Calculations\n",

-      "print(\"input power from source=%.0f kW\" %(P/1000))\n",

-      "R_eq=V_s/(a*I_a)    \n",

-      "print(\"equivalent input resistance=%.3f ohm\" %R_eq)\n",

-      "k=.004\n",

-      "R=.04+.06\n",

-      "w_m=(a*V_s-I_a*R)/(k*I_a)\n",

-      "N=w_m*60/(2*math.pi)    \n",

-      "print(\"motor speed=%.1f rpm\" %N)\n",

-      "T_e=k*I_a**2    \n",

-      "\n",

-      "#Results\n",

-      "print(\"motor torque=%.0f Nm\" %T_e)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "input power from source=108 kW\n",

-        "equivalent input resistance=3.333 ohm\n",

-        "motor speed=2626.1 rpm\n",

-        "motor torque=360 Nm\n"

-       ]

-      }

-     ],

-     "prompt_number": 16

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.17, Page No 686"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "T_on=10.0\n",

-      "T_off=15.0\n",

-      "\n",

-      "#Calculations\n",

-      "a=T_on/(T_on+T_off)\n",

-      "V_s=230.0\n",

-      "V_t=a*V_s\n",

-      "r_a=3\n",

-      "K_m=.5\n",

-      "N=1500\n",

-      "w_m=2*math.pi*N/60\n",

-      "I_a=(V_t-K_m*w_m)/r_a    \n",

-      "\n",

-      "#Results\n",

-      "print(\"motor load current=%.3f A\" %I_a)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "motor load current=4.487 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 17

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.18, Page No 686"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "w_m=0    \n",

-      "print(\"lower limit of speed control=%.0f rpm\" %w_m)\n",

-      "I_a=25.0\n",

-      "r_a=.2\n",

-      "V_s=220\n",

-      "K_m=0.08\n",

-      "\n",

-      "#Calculations\n",

-      "a=(K_m*w_m+I_a*r_a)/V_s    \n",

-      "print(\"lower limit of duty cycle=%.3f\" %a)\n",

-      "a=1    \n",

-      "print(\"upper limit of duty cycle=%.0f\" %a)\n",

-      "w_m=(a*V_s-I_a*r_a)/K_m    \n",

-      "\n",

-      "#Results\n",

-      "print(\"upper limit of speed control=%.1f rpm\" %w_m)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "lower limit of speed control=0 rpm\n",

-        "lower limit of duty cycle=0.023\n",

-        "upper limit of duty cycle=1\n",

-        "upper limit of speed control=2687.5 rpm\n"

-       ]

-      }

-     ],

-     "prompt_number": 18

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.21, Page No 691"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "a=0.6\n",

-      "V_s=400.0\n",

-      "V_t=(1-a)*V_s\n",

-      "I_a=300.0\n",

-      "P=V_t*I_a  \n",

-      "\n",

-      "#Calculations  \n",

-      "print(\"power returned=%.0f kW\" %(P/1000))\n",

-      "r_a=.2\n",

-      "K_m=1.2\n",

-      "R_eq=(1-a)*V_s/I_a+r_a    \n",

-      "print(\"equivalent load resistance=%.4f ohm\" %R_eq)\n",

-      "w_mn=I_a*r_a/K_m\n",

-      "N=w_mn*60/(2*math.pi)    \n",

-      "print(\"min braking speed=%.2f rpm\" %N)\n",

-      "w_mx=(V_s+I_a*r_a)/K_m\n",

-      "N=w_mx*60/(2*math.pi)    \n",

-      "print(\"max braking speed=%.1f rpm\" %N)\n",

-      "w_m=(V_t+I_a*r_a)/K_m\n",

-      "N=w_m*60/(2*math.pi)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"max braking speed=%.1f rpm\" %N)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "power returned=48 kW\n",

-        "equivalent load resistance=0.7333 ohm\n",

-        "min braking speed=477.46 rpm\n",

-        "max braking speed=3660.6 rpm\n",

-        "max braking speed=1750.7 rpm\n"

-       ]

-      }

-     ],

-     "prompt_number": 19

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.22, Page No 699"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "N=1500.0\n",

-      "\n",

-      "#Calculations\n",

-      "print(\"when speed=1455rpm\")\n",

-      "n=1455.0\n",

-      "s1=(N-n)/N\n",

-      "r=math.sqrt(1/3)*(2/3)/(math.sqrt(s1)*(1-s1))    \n",

-      "print(\"I_2mx/I_2r=%.3f\" %r)\n",

-      "print(\"when speed=1350rpm\")\n",

-      "n=1350\n",

-      "s1=(N-n)/N\n",

-      "r=math.sqrt(1/3)*(2/3)/(math.sqrt(s1)*(1-s1))    \n",

-      "\n",

-      "#Results\n",

-      "print(\"I_2mx/I_2r=%.3f\" %r)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "when speed=1455rpm\n",

-        "I_2mx/I_2r=0.000\n",

-        "when speed=1350rpm\n",

-        "I_2mx/I_2r=0.000\n"

-       ]

-      }

-     ],

-     "prompt_number": 20

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.24, Page No 705"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V1=400.0\n",

-      "r1=0.6\n",

-      "r2=0.4\n",

-      "s=1.0\n",

-      "x1=1.6\n",

-      "x2=1.6\n",

-      "\n",

-      "#Calculations\n",

-      "print(\"at starting in normal conditions\")\n",

-      "I_n=V1/math.sqrt((r1+r2/s)**2+(x1+x2)**2)    \n",

-      "print(\"current=%.2f A\" %I_n)\n",

-      "pf=(r1+r2)/math.sqrt((r1+r2/s)**2+(x1+x2)**2)    \n",

-      "print(\"pf=%.4f\" %pf)\n",

-      "f1=50\n",

-      "w_s=4*math.pi*f1/4\n",

-      "T_en=(3/w_s)*I_n**2*(r2/s)    \n",

-      "print(\"\\nTorque developed=%.2f Nm\" %T_en)\n",

-      "print(\"motor is operated with DOL starting\")\n",

-      "I_d=V1/2/math.sqrt((r1+r2/s)**2+((x1+x2)/2)**2)    \n",

-      "print(\"current=%.0f A\" %I_d)\n",

-      "pf=(r1+r2)/math.sqrt((r1+r2/s)**2+((x1+x2)/2)**2)    \n",

-      "print(\"pf=%.2f\" %pf)\n",

-      "f1=25\n",

-      "w_s=4*math.pi*f1/4\n",

-      "T_ed=(3/w_s)*I_d**2*(r2/s)    \n",

-      "print(\"Torque developed=%.3f Nm\" %T_ed)\n",

-      "print(\"at max torque conditions\")\n",

-      "s_mn=r2/math.sqrt((r1)**2+((x1+x2))**2)\n",

-      "I_n=V1/math.sqrt((r1+r2/s_mn)**2+(x1+x2)**2)    \n",

-      "print(\"current=%.3f A\" %I_n)\n",

-      "pf=(r1+r2/s_mn)/math.sqrt((r1+r2/s_mn)**2+(x1+x2)**2)    \n",

-      "print(\"pf=%.4f\" %pf)\n",

-      "f1=50\n",

-      "w_s=4*math.pi*f1/4\n",

-      "T_en=(3/w_s)*I_n**2*(r2/s_mn)    \n",

-      "print(\"Torque developed=%.2f Nm\" %T_en)\n",

-      "print(\"motor is operated with DOL starting\")\n",

-      "s_mn=r2/math.sqrt((r1)**2+((x1+x2)/2)**2)\n",

-      "I_d=V1/2/math.sqrt((r1+r2/s_mn)**2+((x1+x2)/2)**2)    \n",

-      "print(\"current=%.3f A\" %I_d)\n",

-      "pf=(r1+r2/s_mn)/math.sqrt((r1+r2/s_mn)**2+((x1+x2)/2)**2)    \n",

-      "print(\"\\npf=%.3f\" %pf)\n",

-      "f1=25\n",

-      "w_s=4*math.pi*f1/4\n",

-      "T_en=(3/w_s)*I_d**2*(r2/s_mn)  \n",

-      "\n",

-      "\n",

-      "#Results  \n",

-      "print(\"Torque developed=%.3f Nm\" %T_en)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "at starting in normal conditions\n",

-        "current=119.31 A\n",

-        "pf=0.2983\n",

-        "\n",

-        "Torque developed=108.75 Nm\n",

-        "motor is operated with DOL starting\n",

-        "current=106 A\n",

-        "pf=0.53\n",

-        "Torque developed=171.673 Nm\n",

-        "at max torque conditions\n",

-        "current=79.829 A\n",

-        "pf=0.7695\n",

-        "Torque developed=396.26 Nm\n",

-        "motor is operated with DOL starting\n",

-        "current=71.199 A\n",

-        "\n",

-        "pf=0.822\n",

-        "Torque developed=330.883 Nm\n"

-       ]

-      }

-     ],

-     "prompt_number": 21

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.25, Page No 709"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "x1=1.0\n",

-      "X_m=50.0\n",

-      "X_e=x1*X_m/(x1+X_m)\n",

-      "V=231.0\n",

-      "V_e=V*X_m/(x1+X_m)\n",

-      "x2=1.0\n",

-      "r2=.4\n",

-      "r1=0\n",

-      "\n",

-      "#Calculations\n",

-      "s_m=r2/(x2+X_e)    \n",

-      "print(\"slip at max torque=%.2f\" %s_m)\n",

-      "s_mT=r2/(x2+X_m)    \n",

-      "print(\"slip at max torque=%.5f\" %s_mT)\n",

-      "f1=50.0\n",

-      "w_s=4*math.pi*f1/4\n",

-      "print(\"for constant voltage input\")\n",

-      "T_est=(3/w_s)*(V_e/math.sqrt(r2**2+(x2+X_e)**2))**2*(r2)    \n",

-      "print(\"starting torque=%.3f Nm\" %T_est)\n",

-      "T_em=(3/w_s)*V_e**2/(2*(x2+X_e))    \n",

-      "print(\"maximum torque developed=%.2f Nm\" %T_em)\n",

-      "print(\"for constant current input\")\n",

-      "I1=28\n",

-      "T_est=(3/w_s)*(I1*X_m)**2/(r2**2+(x2+X_m)**2)*r2    \n",

-      "print(\"starting torque=%.3f Nm\" %T_est)\n",

-      "T_em=(3/w_s)*(I1*X_m)**2/(2*(x2+X_m))   \n",

-      "print(\"maximum torque developed=%.3f Nm\" %T_em)\n",

-      "s=s_mT\n",

-      "i=1\n",

-      "I_m=I1*(r2/s+i*x2)/(r2/s+i*(x2+X_m))\n",

-      "I_m=math.fabs(I_m)\n",

-      "V1=math.sqrt(3)*I_m*X_m    \n",

-      "\n",

-      "#Results\n",

-      "print(\"supply voltage reqd=%.1f V\" %V1)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "slip at max torque=0.20\n",

-        "slip at max torque=0.00784\n",

-        "for constant voltage input\n",

-        "starting torque=95.988 Nm\n",

-        "maximum torque developed=247.31 Nm\n",

-        "for constant current input\n",

-        "starting torque=5.756 Nm\n",

-        "maximum torque developed=366.993 Nm\n",

-        "supply voltage reqd=1236.2 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 22

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.27, Page No 718"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=420.0\n",

-      "V1=V/math.sqrt(3)\n",

-      "T_e=450.0\n",

-      "N=1440.0\n",

-      "n=1000.0\n",

-      "T_L=T_e*(n/N)**2\n",

-      "n1=1500.0\n",

-      "\n",

-      "#Calculations\n",

-      "w_s=2*math.pi*n1/60\n",

-      "w_m=2*math.pi*n/60\n",

-      "a=.8\n",

-      "I_d=T_L*w_s/(2.339*a*V1)\n",

-      "k=0\n",

-      "R=(1-w_m/w_s)*(2.339*a*V1)/(I_d*(1-k))    \n",

-      "print(\"value of chopper resistance=%.4f ohm\" %R)\n",

-      "n=1320.0\n",

-      "T_L=T_e*(n/N)**2\n",

-      "I_d=T_L*w_s/(2.339*a*V1)    \n",

-      "print(\"Inductor current=%.3f A\" %I_d)\n",

-      "w_m=2*math.pi*n/60\n",

-      "k=1-((1-w_m/w_s)*(2.339*a*V1)/(I_d*R))    \n",

-      "print(\"value of duty cycle=%.4f\" %k)\n",

-      "s=(n1-n)/n1\n",

-      "V_d=2.339*s*a*V1    \n",

-      "print(\"Rectifed o/p voltage=%.3f V\" %V_d)\n",

-      "P=V_d*I_d\n",

-      "I2=math.sqrt(2/3)*I_d\n",

-      "r2=0.02\n",

-      "Pr=3*I2**2*r2\n",

-      "I1=a*I2\n",

-      "r1=0.015\n",

-      "Ps=3*I1**2*r1\n",

-      "Po=T_L*w_m\n",

-      "Pi=Po+Ps+Pr+P\n",

-      "eff=Po/Pi*100   \n",

-      "\n",

-      "#Results\n",

-      "print(\"Efficiency(in percent)=%.2f\" %eff)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "value of chopper resistance=2.0132 ohm\n",

-        "Inductor current=130.902 A\n",

-        "value of duty cycle=0.7934\n",

-        "Rectifed o/p voltage=54.449 V\n",

-        "Efficiency(in percent)=88.00\n"

-       ]

-      }

-     ],

-     "prompt_number": 23

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.28, Page No 720"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=400.0\n",

-      "V_ph=V/math.sqrt(3)\n",

-      "N_s=1000.0\n",

-      "N=800.0\n",

-      "a=.7\n",

-      "I_d=110\n",

-      "R=2.0\n",

-      "\n",

-      "#Calculations\n",

-      "k=1-((1-N/N_s)*(2.339*a*V_ph)/(I_d*R))    \n",

-      "print(\"value of duty cycle=%.3f\" %k)\n",

-      "P=I_d**2*R*(1-k)\n",

-      "I1=a*I_d*math.sqrt(2/3)\n",

-      "r1=0.1\n",

-      "r2=0.08\n",

-      "Pr=3*I1**2*(r1+r2)\n",

-      "P_o=20000\n",

-      "P_i=P_o+Pr+P\n",

-      "eff=P_o/P_i*100    \n",

-      "print(\"Efficiency=%.2f\" %eff)\n",

-      "I11=math.sqrt(6)/math.pi*a*I_d\n",

-      "th=43\n",

-      "P_ip=math.sqrt(3)*V*I11*math.cos(math.radians(th))\n",

-      "pf=P_ip/(math.sqrt(3)*V*I11)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"Input power factor=%.4f\" %pf)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "value of duty cycle=0.656\n",

-        "Efficiency=70.62\n",

-        "Input power factor=0.7314\n"

-       ]

-      }

-     ],

-     "prompt_number": 24

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.29, Page No 724"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=420.0\n",

-      "V1=V/math.sqrt(3)\n",

-      "N=1000.0\n",

-      "w_m=2*math.pi*N/60\n",

-      "N_s=1500.0\n",

-      "\n",

-      "#Calculations\n",

-      "s=(N_s-N)/N_s\n",

-      "a=0.8\n",

-      "V_d=2.339*a*s*V1    \n",

-      "print(\"rectified voltage=%.2f V\" %V_d)\n",

-      "T=450.0\n",

-      "N1=1200.0\n",

-      "T_L=T*(N/N1)**2\n",

-      "f1=50\n",

-      "w_s=4*math.pi*f1/4\n",

-      "I_d=w_s*T_L/(2.339*a*V1)    \n",

-      "print(\"inductor current=%.2f A\" %I_d)\n",

-      "a_T=-.4\n",

-      "a1=math.degrees(math.acos(s*a/a_T))\n",

-      "print(\"delay angle of inverter=%.2f deg\" %a1)\n",

-      "\n",

-      "P_s=V_d*I_d\n",

-      "P_o=T_L*w_m\n",

-      "R_d=0.01\n",

-      "P_i=I_d**2*R_d\n",

-      "I2=math.sqrt(2/3)*I_d\n",

-      "r2=0.02\n",

-      "r1=0.015\n",

-      "P_rol=3*I2**2*r2\n",

-      "I1=a*I2\n",

-      "P_sol=3*I1**2*r1\n",

-      "P_i=P_o+P_rol+P_sol+P_i\n",

-      "eff=P_o/P_i*100    \n",

-      "print(\"\\nefficiency=%.2f\" %eff)\n",

-      "w_m=w_s*(1+(-a_T/a)*math.cos(math.radians(a1))-w_s*R_d*T_L/(2.339*a*V1)**2)\n",

-      "N=w_m*60/(2*math.pi) \n",

-      "\n",

-      "#Results   \n",

-      "print(\"motor speed=%.1f rpm\" %N)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rectified voltage=151.25 V\n",

-        "inductor current=108.18 A\n",

-        "delay angle of inverter=131.81 deg\n",

-        "\n",

-        "efficiency=99.64\n",

-        "motor speed=996.4 rpm\n"

-       ]

-      }

-     ],

-     "prompt_number": 25

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.30, Page No 726"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=700.0\n",

-      "E2=V/math.sqrt(3)\n",

-      "N_s=1500.0\n",

-      "N=1200.0\n",

-      "\n",

-      "#Calculations\n",

-      "s=(N_s-N)/N_s\n",

-      "V_dd=0.7\n",

-      "V_dt=1.5\n",

-      "V_d=3*math.sqrt(6)*s*E2/math.pi-2*V_dd\n",

-      "V1=415.0\n",

-      "a=math.degrees(math.acos((3*math.sqrt(2)*E2/math.pi)**-1*(-V_d+2*V_dt)))\n",

-      "\n",

-      "#Results\n",

-      "print(\"firing angle advance=%.2f deg\" %(180-a))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "firing angle advance=70.22 deg\n"

-       ]

-      }

-     ],

-     "prompt_number": 26

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.31, Page No 726"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=700.0\n",

-      "E2=V/math.sqrt(3)\n",

-      "N_s=1500.0\n",

-      "N=1200.0\n",

-      "\n",

-      "#Calculations\n",

-      "s=(N_s-N)/N_s\n",

-      "V_dd=.7\n",

-      "V_dt=1.5\n",

-      "a=0\n",

-      "u=18 #overlap angle in case of rectifier\n",

-      "V_d=3*math.sqrt(6)*s*E2*(math.cos(math.radians(a))+math.cos(math.radians(a+u)))/(2*math.pi)-2*V_dd\n",

-      "V1=415\n",

-      "V_ml=math.sqrt(2)*V1\n",

-      "u=4 #overlap anglein the inverter\n",

-      " #V_dc=-(3*V_ml*(math.cos(math.radians(a))+math.cos(math.radians(a+u)))/(2*math.pi)-2*V_dt)\n",

-      " #V_dc=V_d\n",

-      " #after solving %  (1+math.cos(math.radians(u)))*math.cos(math.radians(a))-math.sin(math.radians(u))*math.sin(math.radians(a))=-.6425\n",

-      "a=math.degrees(math.acos(-.6425/(math.sqrt((1+math.cos(math.radians(u)))**2+math.sin(math.radians(u))**2))))-math.degrees(math.asin(math.sin(math.radians(a))/(1+math.cos(math.radians(u)))))\n",

-      "\n",

-      "#Results\n",

-      "print(\"firing angle advance=%.2f deg\" %(180-a))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "firing angle advance=71.25 deg\n"

-       ]

-      }

-     ],

-     "prompt_number": 27

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.32, Page No 727"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=700.0\n",

-      "E2=V\n",

-      "N_s=1500.0\n",

-      "N=1200.0\n",

-      "\n",

-      "#Calculations\n",

-      "s=(N_s-N)/N_s\n",

-      "V1=415.0\n",

-      "a_T=s*E2/V1    \n",

-      "\n",

-      "#Results\n",

-      "print(\"voltage ratio of the transformer=%.2f\" %a_T)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "voltage ratio of the transformer=0.34\n"

-       ]

-      }

-     ],

-     "prompt_number": 28

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.33, Page No 733"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "P=6.0\n",

-      "N_s=600.0\n",

-      "f1=P*N_s/120.0\n",

-      "V=400.0\n",

-      "f=50.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_t=f1*V/f    \n",

-      "print(\"supply freq=%.0f Hz\" %V_t)\n",

-      "T=340.0\n",

-      "N=1000.0\n",

-      "T_L=T*(N_s/N)**2\n",

-      "w_s=2*math.pi*N_s/60\n",

-      "P=T_L*w_s\n",

-      "I_a=P/(math.sqrt(3)*V_t)    \n",

-      "print(\"armature current=%.2f A\" %I_a)\n",

-      "Z_s=2\n",

-      "X_s=f1/f*math.fabs(Z_s)\n",

-      "V_t=V_t/math.sqrt(3)\n",

-      "Ef=math.sqrt(V_t**2+(I_a*X_s)**2)\n",

-      "print(\"excitation voltage=%.2f V\" %(math.sqrt(3)*Ef))\n",

-      "dl=math.degrees(math.atan(I_a*X_s/V_t))\n",

-      "print(\"load angle=%.2f deg\" %dl)\n",

-      "T_em=(3/w_s)*(Ef*V_t/X_s)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"pull out torque=%.2f Nm\" %T_em)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "supply freq=240 Hz\n",

-        "armature current=18.50 A\n",

-        "excitation voltage=243.06 V\n",

-        "load angle=9.10 deg\n",

-        "pull out torque=773.69 Nm\n"

-       ]

-      }

-     ],

-     "prompt_number": 29

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.34, Page No 736"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "P=4.0\n",

-      "f=50.0\n",

-      "w_s=4*math.pi*f/P\n",

-      "X_d=8.0\n",

-      "X_q=2.0\n",

-      "T_e=80.0\n",

-      "V=400.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_t=V/math.sqrt(3)\n",

-      "dl=(1/2)*math.degrees(math.asin(T_e*w_s/((3/2)*(V_t)**2*(1/X_q-1/X_d))))    \n",

-      "print(\"load angle=%.3f deg\" %dl)\n",

-      "I_d=V_t*math.cos(math.radians(dl))/X_d\n",

-      "I_q=V_t*math.sin(math.radians(dl))/X_q\n",

-      "I_a=math.sqrt(I_d**2+I_q**2)    \n",

-      "print(\"armature current=%.2f A\" %I_a)\n",

-      "pf=T_e*w_s/(math.sqrt(3)*V*I_a)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"input power factor=%.4f\" %pf)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "load angle=0.000 deg\n",

-        "armature current=28.87 A\n",

-        "input power factor=0.6283\n"

-       ]

-      }

-     ],

-     "prompt_number": 30

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.35, Page No 737"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "T_e=3.0\n",

-      "K_m=1.2\n",

-      "I_a=T_e/K_m\n",

-      "r_a=2.0\n",

-      "V=230.0\n",

-      "\n",

-      "#Calculations\n",

-      "E_a=(0.263*math.sqrt(2)*V-I_a*r_a)/(1-55/180)\n",

-      "w_m=E_a/K_m\n",

-      "N=w_m*60/(2*math.pi)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"motor speed=%.2f rpm\" %N)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "motor speed=640.96 rpm\n"

-       ]

-      }

-     ],

-     "prompt_number": 31

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.36, Page No 738"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "K_m=1.0\n",

-      "N=1360.0\n",

-      "\n",

-      "#Calculations\n",

-      "w_m=2*math.pi*N/60\n",

-      "E_a=K_m*w_m\n",

-      " #after calculations V_t % calculated\n",

-      "V_t=163.45\n",

-      "r_a=4\n",

-      "I_a=(V_t-E_a)/r_a\n",

-      "T_e=K_m*I_a    \n",

-      "\n",

-      "#Results\n",

-      "print(\"motor torque=%.4f Nm\" %T_e)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "motor torque=5.2578 Nm\n"

-       ]

-      }

-     ],

-     "prompt_number": 32

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.37, Page No 740"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "K_m=1.0\n",

-      "N=2100.0\n",

-      "\n",

-      "#Calculations\n",

-      "w_m=2*math.pi*N/60\n",

-      "E_a=K_m*w_m\n",

-      " #after calculations V_t % calculated\n",

-      "V_t=227.66\n",

-      "r_a=4\n",

-      "I_a=(V_t-E_a)/r_a\n",

-      "T_e=K_m*I_a    \n",

-      "\n",

-      "#Results\n",

-      "print(\"motor torque=%.2f Nm\" %T_e)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "motor torque=1.94 Nm\n"

-       ]

-      }

-     ],

-     "prompt_number": 33

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.38, Page No 742"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "K_m=1.0\n",

-      "N=840.0\n",

-      "\n",

-      "#Calculations\n",

-      "w_m=2*math.pi*N/60\n",

-      "E_a=K_m*w_m\n",

-      "V=230.0\n",

-      "a=75.0\n",

-      "V_t=math.sqrt(2)*V/math.pi*(1+math.cos(math.radians(a)))\n",

-      "r_a=4\n",

-      "I_a=(V_t-E_a)/r_a\n",

-      "T_e=K_m*I_a    \n",

-      "\n",

-      "#Results\n",

-      "print(\"motor torque=%.4f Nm\" %T_e)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits.\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "motor torque=10.5922 Nm\n"

-       ]

-      }

-     ],

-     "prompt_number": 34

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.39, Page No 743"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "K_m=1.0\n",

-      "N=1400.0\n",

-      "\n",

-      "#Calculations\n",

-      "w_m=2*math.pi*N/60\n",

-      "E_a=K_m*w_m\n",

-      "V=230.0\n",

-      "a=60.0\n",

-      "a1=212\n",

-      "V_t=math.sqrt(2)*V/math.pi*(math.cos(math.radians(a))-math.cos(math.radians(a1)))+E_a*(180+a-a1)/180\n",

-      "r_a=3\n",

-      "I_a=(V_t-E_a)/r_a\n",

-      "T_e=K_m*I_a   \n",

-      "\n",

-      "#Results\n",

-      "print(\"motor torque=%.3f Nm\" %T_e)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "motor torque=5.257 Nm\n"

-       ]

-      }

-     ],

-     "prompt_number": 35

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.40, Page No 745"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "K_m=1.0\n",

-      "N=600.0\n",

-      "w_m=2*math.pi*N/60\n",

-      "E_a=K_m*w_m\n",

-      "V=230.0\n",

-      "a=60.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_t=2*math.sqrt(2)*V/math.pi*(math.cos(math.radians(a)))\n",

-      "r_a=3\n",

-      "I_a=(V_t-E_a)/r_a\n",

-      "T_e=K_m*I_a    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"motor torque=%.3f Nm\" %T_e)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "motor torque=13.568 Nm\n"

-       ]

-      }

-     ],

-     "prompt_number": 36

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.41, Page No 745"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "r1=.6\n",

-      "r2=.4\n",

-      "s=0.04\n",

-      "x1=1.6\n",

-      "x2=1.6\n",

-      "Z=(r1+r2/s)+(x1+x2)\n",

-      "V=400.0\n",

-      "I1=V/Z    \n",

-      "print(\"source current=%.3f A \" %math.degrees(math.atan(I1.imag/I1.real)))\n",

-      "print(\"and with %.1f deg phase\" %math.fabs(I1))\n",

-      "I2=V/Z\n",

-      "N=1500\n",

-      "w_s=2*math.pi*N/60\n",

-      "T_e=(3/w_s)*abs(I2)**2*r2/s    \n",

-      "print(\"motor torque=%.2f Nm\" %T_e)\n",

-      "N_r=N*(1-s)\n",

-      "\n",

-      "f=45\n",

-      "N_s1=120*f/4\n",

-      "w_s=2*math.pi*N_s1/60\n",

-      "s1=(N_s1-N_r)/N_s1\n",

-      "Z=(r1+r2/s1)+(x1+x2)*f/50.0\n",

-      "V=360\n",

-      "I1=V/Z    \n",

-      "print(\"source current=%.3f A \" %math.degrees(math.atan(I1.imag/I1.real)))\n",

-      "print(\"and with %.1f deg phase\" %math.fabs(I1))\n",

-      "I2=V/Z\n",

-      "T_e=(3/w_s)*abs(I2)**2*r2/s1    \n",

-      "print(\"motor torque=%.2f Nm\" %T_e)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "source current=0.000 A \n",

-        "and with 29.0 deg phase\n",

-        "motor torque=160.46 Nm\n",

-        "source current=-0.000 A \n",

-        "and with 142.9 deg phase\n",

-        "motor torque=-2598.45 Nm\n"

-       ]

-      }

-     ],

-     "prompt_number": 37

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Power_Electronics/Chapter12_4.ipynb b/_Power_Electronics/Chapter12_4.ipynb
deleted file mode 100755
index f8605d69..00000000
--- a/_Power_Electronics/Chapter12_4.ipynb
+++ /dev/null
@@ -1,1997 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 12 : Electic Drives"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.1, Page No 658"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "T_e=15.0 #Nm\n",

-      "K_m=0.5 #V-s/rad\n",

-      "I_a=T_e/K_m\n",

-      "n_m=1000.0\n",

-      "\n",

-      "#Calculations\n",

-      "w_m=2*math.pi*n_m/60\n",

-      "E_a=K_m*w_m\n",

-      "r_a=0.7\n",

-      "V_t=E_a+I_a*r_a\n",

-      "V_s=230.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "a=math.degrees(math.acos(2*math.pi*V_t/V_m-1))\n",

-      "print(\"firing angle delay=%.3f deg\" %a)\n",

-      "I_Tr=I_a*math.sqrt((180-a)/360)    \n",

-      "print(\"rms value of thyristor current=%.3f A\" %I_Tr)\n",

-      "I_fdr=I_a*math.sqrt((180+a)/360)    \n",

-      "print(\"rms value of freewheeling diode current=%.3f A\" %I_fdr)\n",

-      "pf=V_t*I_a/(V_s*I_Tr)  \n",

-      "\n",

-      "#Results  \n",

-      "print(\"input power factor=%.4f\" %pf)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "firing angle delay=65.349 deg\n",

-        "rms value of thyristor current=16.930 A\n",

-        "rms value of freewheeling diode current=24.766 A\n",

-        "input power factor=0.5652\n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.2, Page No 660"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=230.0\n",

-      "E=150.0\n",

-      "R=8.0\n",

-      "\n",

-      "#Calculations\n",

-      "th1=math.sin(math.radians(E/(math.sqrt(2)*V)))\n",

-      "I_o=(1/(2*math.pi*R))*(2*math.sqrt(2)*230*math.cos(math.radians(th1))-E*(math.pi-2*th1*math.pi/180))    \n",

-      "P=E*I_o    \n",

-      "I_or=math.sqrt((1/(2*math.pi*R**2))*((V**2+E**2)*(math.pi-2*th1*math.pi/180)+V**2*math.sin(math.radians(2*th1))-4*math.sqrt(2)*V*E*math.cos(math.radians(th1))))\n",

-      "P_r=I_or**2*R    \n",

-      "pf=(P+P_r)/(V*I_or)\n",

-      "\n",

-      "#Results\n",

-      "print(\"avg charging curent=%.4f A\" %I_o)\n",

-      "print(\"power supplied to the battery=%.2f W\" %P)\n",

-      "print(\"power dissipated by the resistor=%.3f W\" %P_r)    \n",

-      "print(\"supply pf=%.3f\" %pf)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "avg charging curent=3.5679 A\n",

-        "power supplied to the battery=535.18 W\n",

-        "power dissipated by the resistor=829.760 W\n",

-        "supply pf=0.583\n"

-       ]

-      }

-     ],

-     "prompt_number": 2

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.3 Page No 661"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variablesV_s=250\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "a=30.0\n",

-      "k=0.03 #Nm/A**2\n",

-      "n_m=1000.0\n",

-      "\n",

-      "#Calculations\n",

-      "w_m=2*math.pi*n_m/60\n",

-      "r=.2 #r_a+r_s\n",

-      "V_t=V_m/math.pi*(1+math.cos(math.radians(a)))\n",

-      "I_a=V_t/(k*w_m+r)   \n",

-      "print(\"motor armature current=%.2f A\" %I_a)\n",

-      "T_e=k*I_a**2    \n",

-      "print(\"motor torque=%.3f Nm\" %T_e)\n",

-      "I_sr=I_a*math.sqrt((180-a)/180)\n",

-      "pf=(V_t*I_a)/(V_s*I_sr)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"input power factor=%.2f\" %pf)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "motor armature current=57.82 A\n",

-        "motor torque=100.285 Nm\n",

-        "input power factor=0.92\n"

-       ]

-      }

-     ],

-     "prompt_number": 3

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.4, Page No 663"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=400.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "V_f=2*V_m/math.pi\n",

-      "r_f=200.0\n",

-      "I_f=V_f/r_f\n",

-      "T_e=85.0\n",

-      "K_a=0.8\n",

-      "\n",

-      "#Calculations\n",

-      "I_a=T_e/(I_f*K_a)    \n",

-      "print(\"rated armature current=%.2f A\" %I_a)\n",

-      "n_m=1200.0\n",

-      "w_m=2*math.pi*n_m/60\n",

-      "r_a=0.2\n",

-      "V_t=K_a*I_f*w_m+I_a*r_a\n",

-      "a=math.degrees(math.acos(V_t*math.pi/(2*V_m)))\n",

-      "print(\"firing angle delay=%.2f deg\" %a)\n",

-      "E_a=V_t\n",

-      "w_mo=E_a/(K_a*I_f)\n",

-      "N=60*w_mo/(2*math.pi)\n",

-      "reg=((N-n_m)/n_m)*100    \n",

-      "print(\"speed regulation at full load=%.2f\" %reg)\n",

-      "I_ar=I_a\n",

-      "pf=(V_t*I_a)/(V_s*I_ar)    \n",

-      "print(\"input power factor of armature convertor=%.4f\" %pf)\n",

-      "I_fr=I_f\n",

-      "I_sr=math.sqrt(I_fr**2+I_ar**2)\n",

-      "VA=I_sr*V_s\n",

-      "P=V_t*I_a+V_f*I_f\n",

-      "\n",

-      "#Results\n",

-      "print(\"input power factor of drive=%.4f\" %(P/VA))\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rated armature current=59.01 A\n",

-        "firing angle delay=57.63 deg\n",

-        "speed regulation at full load=6.52\n",

-        "input power factor of armature convertor=0.4821\n",

-        "input power factor of drive=0.5093\n"

-       ]

-      }

-     ],

-     "prompt_number": 4

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.5 Page No 664"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=400.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "V_f=2*V_m/math.pi\n",

-      "\n",

-      "#Calculations\n",

-      "a1=math.degrees(math.acos(V_t*math.pi/(2*V_m))) \n",

-      "print(\"delay angle of field converter=%.0f deg\" %a1)\n",

-      "r_f=200.0\n",

-      "I_f=V_f/r_f\n",

-      "T_e=85.0\n",

-      "K_a=0.8\n",

-      "I_a=T_e/(I_f*K_a)\n",

-      "n_m=1200.0\n",

-      "w_m=2*math.pi*n_m/60\n",

-      "r_a=0.1\n",

-      "I_a=50.0\n",

-      "V_t=-K_a*I_f*w_m+I_a*r_a\n",

-      "a=math.degrees(math.acos(V_t*math.pi/(2*V_m)))\n",

-      "\n",

-      "#Results\n",

-      "print(\"firing angle delay of armature converter=%.3f deg\" %a)\n",

-      "print(\"power fed back to ac supply=%.0f W\" %(-V_t*I_a))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "delay angle of field converter=58 deg\n",

-        "firing angle delay of armature converter=119.260 deg\n",

-        "power fed back to ac supply=8801 W\n"

-       ]

-      }

-     ],

-     "prompt_number": 5

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.6 Page No 665"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_t=220.0\n",

-      "n_m=1500.0\n",

-      "w_m=2*math.pi*n_m/60\n",

-      "I_a=10.0\n",

-      "r_a=1.0\n",

-      "\n",

-      "#Calculations\n",

-      "K_m=(V_t-I_a*r_a)/(w_m)\n",

-      "T=5.0\n",

-      "I_a=T/K_m\n",

-      "V_s=230.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "a=30.0\n",

-      "V_t=2*V_m*math.cos(math.radians(a))/math.pi\n",

-      "w_m=(V_t-I_a*r_a)/K_m\n",

-      "N=w_m*60/(2*math.pi)    \n",

-      "\n",

-      "print(\"motor speed=%.2f rpm\" %N)\n",

-      "a=45\n",

-      "n_m=1000\n",

-      "w_m=2*math.pi*n_m/60\n",

-      "V_t=2*V_m*math.cos(math.radians(a))/math.pi\n",

-      "I_a=(V_t-K_m*w_m)/r_a\n",

-      "T_e=K_m*I_a    \n",

-      "\n",

-      "#Results\n",

-      "print(\"torque developed=%.3f Nm\" %T_e)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "motor speed=1254.22 rpm\n",

-        "torque developed=8.586 Nm\n"

-       ]

-      }

-     ],

-     "prompt_number": 6

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.7, Page No 666"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_t=220.0\n",

-      "n_m=1000.0\n",

-      "w_m=2*math.pi*n_m/60\n",

-      "I_a=60.0\n",

-      "r_a=.1\n",

-      "\n",

-      "#Calculations\n",

-      "K_m=(V_t-I_a*r_a)/(w_m)\n",

-      "V_s=230\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "print(\"for 600rpm speed\")\n",

-      "n_m=600.0\n",

-      "w_m=2*math.pi*n_m/60\n",

-      "a=math.degrees(math.acos((K_m*w_m+I_a*r_a)*math.pi/(2*V_m))) \n",

-      "print(\"firing angle=%.3f deg\" %a)\n",

-      "print(\"for -500rpm speed\")\n",

-      "n_m=-500.0\n",

-      "w_m=2*math.pi*n_m/60\n",

-      "a=math.degrees(math.acos((K_m*w_m+I_a*r_a)*math.pi/(2*V_m)))\n",

-      "print(\"firing angle=%.2f deg\" %a)\n",

-      "I_a=I_a/2\n",

-      "a=150\n",

-      "V_t=2*V_m*math.cos(math.radians(a))/math.pi\n",

-      "w_m=(V_t-I_a*r_a)/K_m\n",

-      "N=w_m*60/(2*math.pi)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"motor speed=%.3f rpm\" %N)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for 600rpm speed\n",

-        "firing angle=49.530 deg\n",

-        "for -500rpm speed\n",

-        "firing angle=119.19 deg\n",

-        "motor speed=-852.011 rpm\n"

-       ]

-      }

-     ],

-     "prompt_number": 7

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.8 Page No 672"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "K_m=1.5\n",

-      "T_e=50.0\n",

-      "I_a=T_e/K_m\n",

-      "r_a=0.9\n",

-      "a=45.0\n",

-      "V_s=415.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_ml=math.sqrt(2)*V_s\n",

-      "w_m=((3*V_ml*(1+math.cos(math.radians(a)))/(2*math.pi))-I_a*r_a)/K_m\n",

-      "N=w_m*60/(2*math.pi)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"motor speed=%.2f rpm\" %N)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "motor speed=2854.42 rpm\n"

-       ]

-      }

-     ],

-     "prompt_number": 8

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.9 Page No 672"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variablesV_t=600\n",

-      "n_m=1500.0\n",

-      "w_m=2*math.pi*n_m/60\n",

-      "I_a=80.0\n",

-      "r_a=1.0\n",

-      "\n",

-      "#Calculations\n",

-      "K_m=(V_t-I_a*r_a)/(w_m)\n",

-      "V_s=400.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "print(\"for firing angle=45deg and speed=1200rpm\")\n",

-      "a=45.0\n",

-      "n_m=1200.0\n",

-      "w_m=2*math.pi*n_m/60\n",

-      "I_a=(3*V_m*(1+math.cos(math.radians(a)))/(2*math.pi)-K_m*w_m)/r_a\n",

-      "I_sr=I_a*math.sqrt(2/3)    \n",

-      "print(\"rms value of source current=%.3f A\" %I_sr)\n",

-      "print(\"rms value of thyristor current=%.3f A\" %(I_a*math.sqrt(1/3)))\n",

-      "print(\"avg value of thyristor current=%.2f A\" %I_a*(1/3))\n",

-      "pf=(3/(2*math.pi)*(1+math.cos(math.radians(a))))    \n",

-      "print(\"input power factor=%.3f\" %pf)\n",

-      "\n",

-      "print(\"for firing angle=90deg and speed=700rpm\")\n",

-      "a=90\n",

-      "n_m=700\n",

-      "w_m=2*math.pi*n_m/60\n",

-      "I_a=(3*V_m*(1+math.cos(math.radians(a)))/(2*math.pi)-K_m*w_m)/r_a\n",

-      "I_sr=I_a*math.sqrt(90/180)    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"rms value of source current=%.3f A\" %I_sr)\n",

-      "print(\"rms value of thyristor current=%.3f A\" %(I_a*math.sqrt(90.0/360)))\n",

-      "print(\"avg value of thyristor current=%.3f A\" %I_a*(1/3))\n",

-      "pf=(math.sqrt(6)/(2*math.pi)*(1+math.cos(math.radians(a))))*math.sqrt(180/(180-a))    \n",

-      "print(\"input power factor=%.4f\" %pf)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for firing angle=45deg and speed=1200rpm\n",

-        "rms value of source current=0.000 A\n",

-        "rms value of thyristor current=0.000 A\n",

-        "\n",

-        "input power factor=0.815\n",

-        "for firing angle=90deg and speed=700rpm\n",

-        "rms value of source current=0.000 A\n",

-        "rms value of thyristor current=195.558 A\n",

-        "\n",

-        "input power factor=0.5513\n"

-       ]

-      }

-     ],

-     "prompt_number": 9

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.10 Page No 676"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=400.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "a=30\n",

-      "V_t=3*V_m*math.cos(math.radians(a))/math.pi\n",

-      "I_a=21.0\n",

-      "r_a=.1\n",

-      "V_d=2.0\n",

-      "K_m=1.6\n",

-      "\n",

-      "#Calculations\n",

-      "w_m=(V_t-I_a*r_a-V_d)/K_m\n",

-      "N=w_m*60/(2*math.pi)    \n",

-      "print(\"speed of motor=%.1f rpm\" %N)\n",

-      "\n",

-      "N=2000\n",

-      "w_m=2*math.pi*N/60\n",

-      "I_a=210\n",

-      "V_t=K_m*w_m+I_a*r_a+V_d\n",

-      "a=math.degrees(math.acos(V_t*math.pi/(3*V_m)))\n",

-      "print(\"firing angle=%.2f deg\" %a)\n",

-      "I_sr=I_a*math.sqrt(2.0/3.0)\n",

-      "pf=V_t*I_a/(math.sqrt(3)*V_s*I_sr)    \n",

-      "print(\"supply power factor=%.3f\" %pf)\n",

-      "\n",

-      "I_a=21\n",

-      "w_m=(V_t-I_a*r_a-V_d)/K_m\n",

-      "n=w_m*60/(2*math.pi)\n",

-      "reg=(n-N)/N*100    \n",

-      "\n",

-      "#Results\n",

-      "print(\"speed regulation(percent)=%.2f\" %reg)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "speed of motor=2767.6 rpm\n",

-        "firing angle=48.48 deg\n",

-        "supply power factor=0.633\n",

-        "speed regulation(percent)=5.64\n"

-       ]

-      }

-     ],

-     "prompt_number": 10

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.11, Page No 677"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_t=230.0\n",

-      "V_l=V_t*math.pi/(3*math.sqrt(2))\n",

-      "V_ph=V_l/math.sqrt(3)\n",

-      "V_in=400     #per phase voltage input\n",

-      "\n",

-      "#Calculations\n",

-      "N1=1500.0\n",

-      "I_a1=20.0\n",

-      "r_a1=.6\n",

-      "E_a1=V_t-I_a1*r_a1\n",

-      "n1=1000.0\n",

-      "E_a2=E_a1/1500.0*1000.0\n",

-      "V_t1=E_a1+I_a1*r_a1\n",

-      "a1=math.degrees(math.acos(V_t1*math.pi/(3*math.sqrt(2.0)*V_l)))\n",

-      "I_a2=.5*I_a1\n",

-      "n2=-900.0\n",

-      "V_t2=n2*E_a2/N1+I_a2*r_a1\n",

-      "a2=math.degrees(math.acos(V_t2*math.pi/(3*math.sqrt(2)*V_l))) \n",

-      "\n",

-      "#Results\n",

-      "print(\"transformer phase turns ratio=%.3f\" %(V_in/V_ph))\n",

-      "print(\"for motor running at 1000rpm at rated torque\")\n",

-      "print(\"firing angle delay=%.2f deg\" %a1)\n",

-      "print(\"for motor running at -900rpm at half of rated torque\")\n",

-      "print(\"firing angle delay=%.3f deg\" %a2)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "transformer phase turns ratio=4.068\n",

-        "for motor running at 1000rpm at rated torque\n",

-        "firing angle delay=0.00 deg\n",

-        "for motor running at -900rpm at half of rated torque\n",

-        "firing angle delay=110.674 deg\n"

-       ]

-      }

-     ],

-     "prompt_number": 11

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.12, Page No 678"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variablesV_s=400\n",

-      "V_ml=math.sqrt(2)*V_s\n",

-      "V_f=3*V_ml/math.pi\n",

-      "R_f=300.0\n",

-      "I_f=V_f/R_f\n",

-      "T_e=60.0\n",

-      "k=1.1\n",

-      "\n",

-      "#Calculations\n",

-      "I_a=T_e/(k*I_f)\n",

-      "N1=1000.0\n",

-      "w_m1=2*math.pi*N1/60\n",

-      "r_a1=.3\n",

-      "V_t1=k*I_f*w_m1+I_a*r_a1\n",

-      "a1=math.degrees(math.acos(V_f*math.pi/(3*V_ml)))\n",

-      "N2=3000\n",

-      "w_m2=2*math.pi*N/60\n",

-      "a2=0\n",

-      "V_t2=3*V_ml*math.cos(math.radians(a))/math.pi\n",

-      "I_f2=(V_t2-I_a*r_a)/(w_m2*k)\n",

-      "V_f2=I_f2*R_f\n",

-      "a2=math.degrees(math.acos(V_f2*math.pi/(3*V_ml)))\n",

-      "\n",

-      "#Results\n",

-      "print(\"firing angle=%.3f deg\" %a)\n",

-      "print(\"firing angle=%.3f deg\" %a)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "firing angle=48.477 deg\n",

-        "firing angle=48.477 deg\n"

-       ]

-      }

-     ],

-     "prompt_number": 12

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.13, Page No 679"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      " #after calculating\n",

-      " #t=w_m/6000-math.pi/360\n",

-      "\n",

-      "N=1000.0\n",

-      "\n",

-      "#Calculations\n",

-      "w_m=2*math.pi*N/60\n",

-      "t=w_m/6000-math.pi/360    \n",

-      "\n",

-      "#Results\n",

-      "print(\"time reqd=%.2f s\" %t)\n",

-      " #printing mistake in the answer in book"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "time reqd=0.01 s\n"

-       ]

-      }

-     ],

-     "prompt_number": 13

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.14, Page No 679"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "I_a=1.0 #supposition\n",

-      "a=60.0\n",

-      "\n",

-      "#Calculations\n",

-      "I_s1=2*math.sqrt(2)/math.pi*I_a*math.sin(math.radians(a))\n",

-      "I_s3=2*math.sqrt(2)/(3*math.pi)*I_a*math.sin(math.radians(3*a))\n",

-      "I_s5=2*math.sqrt(2)/(5*math.pi)*I_a*math.sin(math.radians(5*a))\n",

-      "per3=I_s3/I_s1*100    \n",

-      "print(\"percent of 3rd harmonic current in fundamental=%.2f\" %per3)\n",

-      "per5=I_s5/I_s1*100    \n",

-      "\n",

-      "#Results\n",

-      "print(\"percent of 5th harmonic current in fundamental=%.2f\" %per5)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "percent of 3rd harmonic current in fundamental=0.00\n",

-        "percent of 5th harmonic current in fundamental=-20.00\n"

-       ]

-      }

-     ],

-     "prompt_number": 14

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.15, Page No 680"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "I_a=60.0\n",

-      "I_TA=I_a/3    \n",

-      "\n",

-      "#Calculations\n",

-      "print(\"avg thyristor current=%.0f A\" %I_TA)\n",

-      "I_Tr=I_a/math.sqrt(3)    \n",

-      "print(\"rms thyristor current=%.3f A\" %I_Tr)\n",

-      "V_s=400\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "I_sr=I_a*math.sqrt(2.0/3)\n",

-      "a=150\n",

-      "V_t=3*V_m*math.cos(math.radians(a))/math.pi\n",

-      "pf=V_t*I_a/(math.sqrt(3)*V_s*I_sr)    \n",

-      "print(\"power factor of ac source=%.3f\" %pf)\n",

-      "\n",

-      "r_a=0.5\n",

-      "K_m=2.4\n",

-      "w_m=(V_t-I_a*r_a)/K_m\n",

-      "N=w_m*60/(2*math.pi)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"Speed of motor=%.2f rpm\" %N)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "avg thyristor current=20 A\n",

-        "rms thyristor current=34.641 A\n",

-        "power factor of ac source=-0.827\n",

-        "Speed of motor=-1980.76 rpm\n"

-       ]

-      }

-     ],

-     "prompt_number": 15

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.16, Page No 685"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "I_a=300.0\n",

-      "V_s=600.0\n",

-      "a=0.6\n",

-      "V_t=a*V_s\n",

-      "P=V_t*I_a    \n",

-      "\n",

-      "#Calculations\n",

-      "print(\"input power from source=%.0f kW\" %(P/1000))\n",

-      "R_eq=V_s/(a*I_a)    \n",

-      "print(\"equivalent input resistance=%.3f ohm\" %R_eq)\n",

-      "k=.004\n",

-      "R=.04+.06\n",

-      "w_m=(a*V_s-I_a*R)/(k*I_a)\n",

-      "N=w_m*60/(2*math.pi)    \n",

-      "print(\"motor speed=%.1f rpm\" %N)\n",

-      "T_e=k*I_a**2    \n",

-      "\n",

-      "#Results\n",

-      "print(\"motor torque=%.0f Nm\" %T_e)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "input power from source=108 kW\n",

-        "equivalent input resistance=3.333 ohm\n",

-        "motor speed=2626.1 rpm\n",

-        "motor torque=360 Nm\n"

-       ]

-      }

-     ],

-     "prompt_number": 16

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.17, Page No 686"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "T_on=10.0\n",

-      "T_off=15.0\n",

-      "\n",

-      "#Calculations\n",

-      "a=T_on/(T_on+T_off)\n",

-      "V_s=230.0\n",

-      "V_t=a*V_s\n",

-      "r_a=3\n",

-      "K_m=.5\n",

-      "N=1500\n",

-      "w_m=2*math.pi*N/60\n",

-      "I_a=(V_t-K_m*w_m)/r_a    \n",

-      "\n",

-      "#Results\n",

-      "print(\"motor load current=%.3f A\" %I_a)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "motor load current=4.487 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 17

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.18, Page No 686"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "w_m=0    \n",

-      "print(\"lower limit of speed control=%.0f rpm\" %w_m)\n",

-      "I_a=25.0\n",

-      "r_a=.2\n",

-      "V_s=220\n",

-      "K_m=0.08\n",

-      "\n",

-      "#Calculations\n",

-      "a=(K_m*w_m+I_a*r_a)/V_s    \n",

-      "print(\"lower limit of duty cycle=%.3f\" %a)\n",

-      "a=1    \n",

-      "print(\"upper limit of duty cycle=%.0f\" %a)\n",

-      "w_m=(a*V_s-I_a*r_a)/K_m    \n",

-      "\n",

-      "#Results\n",

-      "print(\"upper limit of speed control=%.1f rpm\" %w_m)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "lower limit of speed control=0 rpm\n",

-        "lower limit of duty cycle=0.023\n",

-        "upper limit of duty cycle=1\n",

-        "upper limit of speed control=2687.5 rpm\n"

-       ]

-      }

-     ],

-     "prompt_number": 18

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.21, Page No 691"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "a=0.6\n",

-      "V_s=400.0\n",

-      "V_t=(1-a)*V_s\n",

-      "I_a=300.0\n",

-      "P=V_t*I_a  \n",

-      "\n",

-      "#Calculations  \n",

-      "print(\"power returned=%.0f kW\" %(P/1000))\n",

-      "r_a=.2\n",

-      "K_m=1.2\n",

-      "R_eq=(1-a)*V_s/I_a+r_a    \n",

-      "print(\"equivalent load resistance=%.4f ohm\" %R_eq)\n",

-      "w_mn=I_a*r_a/K_m\n",

-      "N=w_mn*60/(2*math.pi)    \n",

-      "print(\"min braking speed=%.2f rpm\" %N)\n",

-      "w_mx=(V_s+I_a*r_a)/K_m\n",

-      "N=w_mx*60/(2*math.pi)    \n",

-      "print(\"max braking speed=%.1f rpm\" %N)\n",

-      "w_m=(V_t+I_a*r_a)/K_m\n",

-      "N=w_m*60/(2*math.pi)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"max braking speed=%.1f rpm\" %N)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "power returned=48 kW\n",

-        "equivalent load resistance=0.7333 ohm\n",

-        "min braking speed=477.46 rpm\n",

-        "max braking speed=3660.6 rpm\n",

-        "max braking speed=1750.7 rpm\n"

-       ]

-      }

-     ],

-     "prompt_number": 19

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.22, Page No 699"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "N=1500.0\n",

-      "\n",

-      "#Calculations\n",

-      "print(\"when speed=1455rpm\")\n",

-      "n=1455.0\n",

-      "s1=(N-n)/N\n",

-      "r=math.sqrt(1/3)*(2/3)/(math.sqrt(s1)*(1-s1))    \n",

-      "print(\"I_2mx/I_2r=%.3f\" %r)\n",

-      "print(\"when speed=1350rpm\")\n",

-      "n=1350\n",

-      "s1=(N-n)/N\n",

-      "r=math.sqrt(1/3)*(2/3)/(math.sqrt(s1)*(1-s1))    \n",

-      "\n",

-      "#Results\n",

-      "print(\"I_2mx/I_2r=%.3f\" %r)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "when speed=1455rpm\n",

-        "I_2mx/I_2r=0.000\n",

-        "when speed=1350rpm\n",

-        "I_2mx/I_2r=0.000\n"

-       ]

-      }

-     ],

-     "prompt_number": 20

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.24, Page No 705"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V1=400.0\n",

-      "r1=0.6\n",

-      "r2=0.4\n",

-      "s=1.0\n",

-      "x1=1.6\n",

-      "x2=1.6\n",

-      "\n",

-      "#Calculations\n",

-      "print(\"at starting in normal conditions\")\n",

-      "I_n=V1/math.sqrt((r1+r2/s)**2+(x1+x2)**2)    \n",

-      "print(\"current=%.2f A\" %I_n)\n",

-      "pf=(r1+r2)/math.sqrt((r1+r2/s)**2+(x1+x2)**2)    \n",

-      "print(\"pf=%.4f\" %pf)\n",

-      "f1=50\n",

-      "w_s=4*math.pi*f1/4\n",

-      "T_en=(3/w_s)*I_n**2*(r2/s)    \n",

-      "print(\"\\nTorque developed=%.2f Nm\" %T_en)\n",

-      "print(\"motor is operated with DOL starting\")\n",

-      "I_d=V1/2/math.sqrt((r1+r2/s)**2+((x1+x2)/2)**2)    \n",

-      "print(\"current=%.0f A\" %I_d)\n",

-      "pf=(r1+r2)/math.sqrt((r1+r2/s)**2+((x1+x2)/2)**2)    \n",

-      "print(\"pf=%.2f\" %pf)\n",

-      "f1=25\n",

-      "w_s=4*math.pi*f1/4\n",

-      "T_ed=(3/w_s)*I_d**2*(r2/s)    \n",

-      "print(\"Torque developed=%.3f Nm\" %T_ed)\n",

-      "print(\"at max torque conditions\")\n",

-      "s_mn=r2/math.sqrt((r1)**2+((x1+x2))**2)\n",

-      "I_n=V1/math.sqrt((r1+r2/s_mn)**2+(x1+x2)**2)    \n",

-      "print(\"current=%.3f A\" %I_n)\n",

-      "pf=(r1+r2/s_mn)/math.sqrt((r1+r2/s_mn)**2+(x1+x2)**2)    \n",

-      "print(\"pf=%.4f\" %pf)\n",

-      "f1=50\n",

-      "w_s=4*math.pi*f1/4\n",

-      "T_en=(3/w_s)*I_n**2*(r2/s_mn)    \n",

-      "print(\"Torque developed=%.2f Nm\" %T_en)\n",

-      "print(\"motor is operated with DOL starting\")\n",

-      "s_mn=r2/math.sqrt((r1)**2+((x1+x2)/2)**2)\n",

-      "I_d=V1/2/math.sqrt((r1+r2/s_mn)**2+((x1+x2)/2)**2)    \n",

-      "print(\"current=%.3f A\" %I_d)\n",

-      "pf=(r1+r2/s_mn)/math.sqrt((r1+r2/s_mn)**2+((x1+x2)/2)**2)    \n",

-      "print(\"\\npf=%.3f\" %pf)\n",

-      "f1=25\n",

-      "w_s=4*math.pi*f1/4\n",

-      "T_en=(3/w_s)*I_d**2*(r2/s_mn)  \n",

-      "\n",

-      "\n",

-      "#Results  \n",

-      "print(\"Torque developed=%.3f Nm\" %T_en)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "at starting in normal conditions\n",

-        "current=119.31 A\n",

-        "pf=0.2983\n",

-        "\n",

-        "Torque developed=108.75 Nm\n",

-        "motor is operated with DOL starting\n",

-        "current=106 A\n",

-        "pf=0.53\n",

-        "Torque developed=171.673 Nm\n",

-        "at max torque conditions\n",

-        "current=79.829 A\n",

-        "pf=0.7695\n",

-        "Torque developed=396.26 Nm\n",

-        "motor is operated with DOL starting\n",

-        "current=71.199 A\n",

-        "\n",

-        "pf=0.822\n",

-        "Torque developed=330.883 Nm\n"

-       ]

-      }

-     ],

-     "prompt_number": 21

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.25, Page No 709"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "x1=1.0\n",

-      "X_m=50.0\n",

-      "X_e=x1*X_m/(x1+X_m)\n",

-      "V=231.0\n",

-      "V_e=V*X_m/(x1+X_m)\n",

-      "x2=1.0\n",

-      "r2=.4\n",

-      "r1=0\n",

-      "\n",

-      "#Calculations\n",

-      "s_m=r2/(x2+X_e)    \n",

-      "print(\"slip at max torque=%.2f\" %s_m)\n",

-      "s_mT=r2/(x2+X_m)    \n",

-      "print(\"slip at max torque=%.5f\" %s_mT)\n",

-      "f1=50.0\n",

-      "w_s=4*math.pi*f1/4\n",

-      "print(\"for constant voltage input\")\n",

-      "T_est=(3/w_s)*(V_e/math.sqrt(r2**2+(x2+X_e)**2))**2*(r2)    \n",

-      "print(\"starting torque=%.3f Nm\" %T_est)\n",

-      "T_em=(3/w_s)*V_e**2/(2*(x2+X_e))    \n",

-      "print(\"maximum torque developed=%.2f Nm\" %T_em)\n",

-      "print(\"for constant current input\")\n",

-      "I1=28\n",

-      "T_est=(3/w_s)*(I1*X_m)**2/(r2**2+(x2+X_m)**2)*r2    \n",

-      "print(\"starting torque=%.3f Nm\" %T_est)\n",

-      "T_em=(3/w_s)*(I1*X_m)**2/(2*(x2+X_m))   \n",

-      "print(\"maximum torque developed=%.3f Nm\" %T_em)\n",

-      "s=s_mT\n",

-      "i=1\n",

-      "I_m=I1*(r2/s+i*x2)/(r2/s+i*(x2+X_m))\n",

-      "I_m=math.fabs(I_m)\n",

-      "V1=math.sqrt(3)*I_m*X_m    \n",

-      "\n",

-      "#Results\n",

-      "print(\"supply voltage reqd=%.1f V\" %V1)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "slip at max torque=0.20\n",

-        "slip at max torque=0.00784\n",

-        "for constant voltage input\n",

-        "starting torque=95.988 Nm\n",

-        "maximum torque developed=247.31 Nm\n",

-        "for constant current input\n",

-        "starting torque=5.756 Nm\n",

-        "maximum torque developed=366.993 Nm\n",

-        "supply voltage reqd=1236.2 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 22

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.27, Page No 718"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=420.0\n",

-      "V1=V/math.sqrt(3)\n",

-      "T_e=450.0\n",

-      "N=1440.0\n",

-      "n=1000.0\n",

-      "T_L=T_e*(n/N)**2\n",

-      "n1=1500.0\n",

-      "\n",

-      "#Calculations\n",

-      "w_s=2*math.pi*n1/60\n",

-      "w_m=2*math.pi*n/60\n",

-      "a=.8\n",

-      "I_d=T_L*w_s/(2.339*a*V1)\n",

-      "k=0\n",

-      "R=(1-w_m/w_s)*(2.339*a*V1)/(I_d*(1-k))    \n",

-      "print(\"value of chopper resistance=%.4f ohm\" %R)\n",

-      "n=1320.0\n",

-      "T_L=T_e*(n/N)**2\n",

-      "I_d=T_L*w_s/(2.339*a*V1)    \n",

-      "print(\"Inductor current=%.3f A\" %I_d)\n",

-      "w_m=2*math.pi*n/60\n",

-      "k=1-((1-w_m/w_s)*(2.339*a*V1)/(I_d*R))    \n",

-      "print(\"value of duty cycle=%.4f\" %k)\n",

-      "s=(n1-n)/n1\n",

-      "V_d=2.339*s*a*V1    \n",

-      "print(\"Rectifed o/p voltage=%.3f V\" %V_d)\n",

-      "P=V_d*I_d\n",

-      "I2=math.sqrt(2/3)*I_d\n",

-      "r2=0.02\n",

-      "Pr=3*I2**2*r2\n",

-      "I1=a*I2\n",

-      "r1=0.015\n",

-      "Ps=3*I1**2*r1\n",

-      "Po=T_L*w_m\n",

-      "Pi=Po+Ps+Pr+P\n",

-      "eff=Po/Pi*100   \n",

-      "\n",

-      "#Results\n",

-      "print(\"Efficiency(in percent)=%.2f\" %eff)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "value of chopper resistance=2.0132 ohm\n",

-        "Inductor current=130.902 A\n",

-        "value of duty cycle=0.7934\n",

-        "Rectifed o/p voltage=54.449 V\n",

-        "Efficiency(in percent)=88.00\n"

-       ]

-      }

-     ],

-     "prompt_number": 23

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.28, Page No 720"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=400.0\n",

-      "V_ph=V/math.sqrt(3)\n",

-      "N_s=1000.0\n",

-      "N=800.0\n",

-      "a=.7\n",

-      "I_d=110\n",

-      "R=2.0\n",

-      "\n",

-      "#Calculations\n",

-      "k=1-((1-N/N_s)*(2.339*a*V_ph)/(I_d*R))    \n",

-      "print(\"value of duty cycle=%.3f\" %k)\n",

-      "P=I_d**2*R*(1-k)\n",

-      "I1=a*I_d*math.sqrt(2/3)\n",

-      "r1=0.1\n",

-      "r2=0.08\n",

-      "Pr=3*I1**2*(r1+r2)\n",

-      "P_o=20000\n",

-      "P_i=P_o+Pr+P\n",

-      "eff=P_o/P_i*100    \n",

-      "print(\"Efficiency=%.2f\" %eff)\n",

-      "I11=math.sqrt(6)/math.pi*a*I_d\n",

-      "th=43\n",

-      "P_ip=math.sqrt(3)*V*I11*math.cos(math.radians(th))\n",

-      "pf=P_ip/(math.sqrt(3)*V*I11)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"Input power factor=%.4f\" %pf)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "value of duty cycle=0.656\n",

-        "Efficiency=70.62\n",

-        "Input power factor=0.7314\n"

-       ]

-      }

-     ],

-     "prompt_number": 24

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.29, Page No 724"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=420.0\n",

-      "V1=V/math.sqrt(3)\n",

-      "N=1000.0\n",

-      "w_m=2*math.pi*N/60\n",

-      "N_s=1500.0\n",

-      "\n",

-      "#Calculations\n",

-      "s=(N_s-N)/N_s\n",

-      "a=0.8\n",

-      "V_d=2.339*a*s*V1    \n",

-      "print(\"rectified voltage=%.2f V\" %V_d)\n",

-      "T=450.0\n",

-      "N1=1200.0\n",

-      "T_L=T*(N/N1)**2\n",

-      "f1=50\n",

-      "w_s=4*math.pi*f1/4\n",

-      "I_d=w_s*T_L/(2.339*a*V1)    \n",

-      "print(\"inductor current=%.2f A\" %I_d)\n",

-      "a_T=-.4\n",

-      "a1=math.degrees(math.acos(s*a/a_T))\n",

-      "print(\"delay angle of inverter=%.2f deg\" %a1)\n",

-      "\n",

-      "P_s=V_d*I_d\n",

-      "P_o=T_L*w_m\n",

-      "R_d=0.01\n",

-      "P_i=I_d**2*R_d\n",

-      "I2=math.sqrt(2/3)*I_d\n",

-      "r2=0.02\n",

-      "r1=0.015\n",

-      "P_rol=3*I2**2*r2\n",

-      "I1=a*I2\n",

-      "P_sol=3*I1**2*r1\n",

-      "P_i=P_o+P_rol+P_sol+P_i\n",

-      "eff=P_o/P_i*100    \n",

-      "print(\"\\nefficiency=%.2f\" %eff)\n",

-      "w_m=w_s*(1+(-a_T/a)*math.cos(math.radians(a1))-w_s*R_d*T_L/(2.339*a*V1)**2)\n",

-      "N=w_m*60/(2*math.pi) \n",

-      "\n",

-      "#Results   \n",

-      "print(\"motor speed=%.1f rpm\" %N)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rectified voltage=151.25 V\n",

-        "inductor current=108.18 A\n",

-        "delay angle of inverter=131.81 deg\n",

-        "\n",

-        "efficiency=99.64\n",

-        "motor speed=996.4 rpm\n"

-       ]

-      }

-     ],

-     "prompt_number": 25

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.30, Page No 726"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=700.0\n",

-      "E2=V/math.sqrt(3)\n",

-      "N_s=1500.0\n",

-      "N=1200.0\n",

-      "\n",

-      "#Calculations\n",

-      "s=(N_s-N)/N_s\n",

-      "V_dd=0.7\n",

-      "V_dt=1.5\n",

-      "V_d=3*math.sqrt(6)*s*E2/math.pi-2*V_dd\n",

-      "V1=415.0\n",

-      "a=math.degrees(math.acos((3*math.sqrt(2)*E2/math.pi)**-1*(-V_d+2*V_dt)))\n",

-      "\n",

-      "#Results\n",

-      "print(\"firing angle advance=%.2f deg\" %(180-a))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "firing angle advance=70.22 deg\n"

-       ]

-      }

-     ],

-     "prompt_number": 26

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.31, Page No 726"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=700.0\n",

-      "E2=V/math.sqrt(3)\n",

-      "N_s=1500.0\n",

-      "N=1200.0\n",

-      "\n",

-      "#Calculations\n",

-      "s=(N_s-N)/N_s\n",

-      "V_dd=.7\n",

-      "V_dt=1.5\n",

-      "a=0\n",

-      "u=18 #overlap angle in case of rectifier\n",

-      "V_d=3*math.sqrt(6)*s*E2*(math.cos(math.radians(a))+math.cos(math.radians(a+u)))/(2*math.pi)-2*V_dd\n",

-      "V1=415\n",

-      "V_ml=math.sqrt(2)*V1\n",

-      "u=4 #overlap anglein the inverter\n",

-      " #V_dc=-(3*V_ml*(math.cos(math.radians(a))+math.cos(math.radians(a+u)))/(2*math.pi)-2*V_dt)\n",

-      " #V_dc=V_d\n",

-      " #after solving %  (1+math.cos(math.radians(u)))*math.cos(math.radians(a))-math.sin(math.radians(u))*math.sin(math.radians(a))=-.6425\n",

-      "a=math.degrees(math.acos(-.6425/(math.sqrt((1+math.cos(math.radians(u)))**2+math.sin(math.radians(u))**2))))-math.degrees(math.asin(math.sin(math.radians(a))/(1+math.cos(math.radians(u)))))\n",

-      "\n",

-      "#Results\n",

-      "print(\"firing angle advance=%.2f deg\" %(180-a))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "firing angle advance=71.25 deg\n"

-       ]

-      }

-     ],

-     "prompt_number": 27

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.32, Page No 727"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=700.0\n",

-      "E2=V\n",

-      "N_s=1500.0\n",

-      "N=1200.0\n",

-      "\n",

-      "#Calculations\n",

-      "s=(N_s-N)/N_s\n",

-      "V1=415.0\n",

-      "a_T=s*E2/V1    \n",

-      "\n",

-      "#Results\n",

-      "print(\"voltage ratio of the transformer=%.2f\" %a_T)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "voltage ratio of the transformer=0.34\n"

-       ]

-      }

-     ],

-     "prompt_number": 28

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.33, Page No 733"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "P=6.0\n",

-      "N_s=600.0\n",

-      "f1=P*N_s/120.0\n",

-      "V=400.0\n",

-      "f=50.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_t=f1*V/f    \n",

-      "print(\"supply freq=%.0f Hz\" %V_t)\n",

-      "T=340.0\n",

-      "N=1000.0\n",

-      "T_L=T*(N_s/N)**2\n",

-      "w_s=2*math.pi*N_s/60\n",

-      "P=T_L*w_s\n",

-      "I_a=P/(math.sqrt(3)*V_t)    \n",

-      "print(\"armature current=%.2f A\" %I_a)\n",

-      "Z_s=2\n",

-      "X_s=f1/f*math.fabs(Z_s)\n",

-      "V_t=V_t/math.sqrt(3)\n",

-      "Ef=math.sqrt(V_t**2+(I_a*X_s)**2)\n",

-      "print(\"excitation voltage=%.2f V\" %(math.sqrt(3)*Ef))\n",

-      "dl=math.degrees(math.atan(I_a*X_s/V_t))\n",

-      "print(\"load angle=%.2f deg\" %dl)\n",

-      "T_em=(3/w_s)*(Ef*V_t/X_s)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"pull out torque=%.2f Nm\" %T_em)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "supply freq=240 Hz\n",

-        "armature current=18.50 A\n",

-        "excitation voltage=243.06 V\n",

-        "load angle=9.10 deg\n",

-        "pull out torque=773.69 Nm\n"

-       ]

-      }

-     ],

-     "prompt_number": 29

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.34, Page No 736"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "P=4.0\n",

-      "f=50.0\n",

-      "w_s=4*math.pi*f/P\n",

-      "X_d=8.0\n",

-      "X_q=2.0\n",

-      "T_e=80.0\n",

-      "V=400.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_t=V/math.sqrt(3)\n",

-      "dl=(1/2)*math.degrees(math.asin(T_e*w_s/((3/2)*(V_t)**2*(1/X_q-1/X_d))))    \n",

-      "print(\"load angle=%.3f deg\" %dl)\n",

-      "I_d=V_t*math.cos(math.radians(dl))/X_d\n",

-      "I_q=V_t*math.sin(math.radians(dl))/X_q\n",

-      "I_a=math.sqrt(I_d**2+I_q**2)    \n",

-      "print(\"armature current=%.2f A\" %I_a)\n",

-      "pf=T_e*w_s/(math.sqrt(3)*V*I_a)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"input power factor=%.4f\" %pf)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "load angle=0.000 deg\n",

-        "armature current=28.87 A\n",

-        "input power factor=0.6283\n"

-       ]

-      }

-     ],

-     "prompt_number": 30

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.35, Page No 737"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "T_e=3.0\n",

-      "K_m=1.2\n",

-      "I_a=T_e/K_m\n",

-      "r_a=2.0\n",

-      "V=230.0\n",

-      "\n",

-      "#Calculations\n",

-      "E_a=(0.263*math.sqrt(2)*V-I_a*r_a)/(1-55/180)\n",

-      "w_m=E_a/K_m\n",

-      "N=w_m*60/(2*math.pi)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"motor speed=%.2f rpm\" %N)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "motor speed=640.96 rpm\n"

-       ]

-      }

-     ],

-     "prompt_number": 31

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.36, Page No 738"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "K_m=1.0\n",

-      "N=1360.0\n",

-      "\n",

-      "#Calculations\n",

-      "w_m=2*math.pi*N/60\n",

-      "E_a=K_m*w_m\n",

-      " #after calculations V_t % calculated\n",

-      "V_t=163.45\n",

-      "r_a=4\n",

-      "I_a=(V_t-E_a)/r_a\n",

-      "T_e=K_m*I_a    \n",

-      "\n",

-      "#Results\n",

-      "print(\"motor torque=%.4f Nm\" %T_e)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "motor torque=5.2578 Nm\n"

-       ]

-      }

-     ],

-     "prompt_number": 32

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.37, Page No 740"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "K_m=1.0\n",

-      "N=2100.0\n",

-      "\n",

-      "#Calculations\n",

-      "w_m=2*math.pi*N/60\n",

-      "E_a=K_m*w_m\n",

-      " #after calculations V_t % calculated\n",

-      "V_t=227.66\n",

-      "r_a=4\n",

-      "I_a=(V_t-E_a)/r_a\n",

-      "T_e=K_m*I_a    \n",

-      "\n",

-      "#Results\n",

-      "print(\"motor torque=%.2f Nm\" %T_e)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "motor torque=1.94 Nm\n"

-       ]

-      }

-     ],

-     "prompt_number": 33

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.38, Page No 742"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "K_m=1.0\n",

-      "N=840.0\n",

-      "\n",

-      "#Calculations\n",

-      "w_m=2*math.pi*N/60\n",

-      "E_a=K_m*w_m\n",

-      "V=230.0\n",

-      "a=75.0\n",

-      "V_t=math.sqrt(2)*V/math.pi*(1+math.cos(math.radians(a)))\n",

-      "r_a=4\n",

-      "I_a=(V_t-E_a)/r_a\n",

-      "T_e=K_m*I_a    \n",

-      "\n",

-      "#Results\n",

-      "print(\"motor torque=%.4f Nm\" %T_e)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits.\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "motor torque=10.5922 Nm\n"

-       ]

-      }

-     ],

-     "prompt_number": 34

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.39, Page No 743"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "K_m=1.0\n",

-      "N=1400.0\n",

-      "\n",

-      "#Calculations\n",

-      "w_m=2*math.pi*N/60\n",

-      "E_a=K_m*w_m\n",

-      "V=230.0\n",

-      "a=60.0\n",

-      "a1=212\n",

-      "V_t=math.sqrt(2)*V/math.pi*(math.cos(math.radians(a))-math.cos(math.radians(a1)))+E_a*(180+a-a1)/180\n",

-      "r_a=3\n",

-      "I_a=(V_t-E_a)/r_a\n",

-      "T_e=K_m*I_a   \n",

-      "\n",

-      "#Results\n",

-      "print(\"motor torque=%.3f Nm\" %T_e)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "motor torque=5.257 Nm\n"

-       ]

-      }

-     ],

-     "prompt_number": 35

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.40, Page No 745"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "K_m=1.0\n",

-      "N=600.0\n",

-      "w_m=2*math.pi*N/60\n",

-      "E_a=K_m*w_m\n",

-      "V=230.0\n",

-      "a=60.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_t=2*math.sqrt(2)*V/math.pi*(math.cos(math.radians(a)))\n",

-      "r_a=3\n",

-      "I_a=(V_t-E_a)/r_a\n",

-      "T_e=K_m*I_a    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"motor torque=%.3f Nm\" %T_e)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "motor torque=13.568 Nm\n"

-       ]

-      }

-     ],

-     "prompt_number": 36

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 12.41, Page No 745"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "r1=.6\n",

-      "r2=.4\n",

-      "s=0.04\n",

-      "x1=1.6\n",

-      "x2=1.6\n",

-      "Z=(r1+r2/s)+(x1+x2)\n",

-      "V=400.0\n",

-      "I1=V/Z    \n",

-      "print(\"source current=%.3f A \" %math.degrees(math.atan(I1.imag/I1.real)))\n",

-      "print(\"and with %.1f deg phase\" %math.fabs(I1))\n",

-      "I2=V/Z\n",

-      "N=1500\n",

-      "w_s=2*math.pi*N/60\n",

-      "T_e=(3/w_s)*abs(I2)**2*r2/s    \n",

-      "print(\"motor torque=%.2f Nm\" %T_e)\n",

-      "N_r=N*(1-s)\n",

-      "\n",

-      "f=45\n",

-      "N_s1=120*f/4\n",

-      "w_s=2*math.pi*N_s1/60\n",

-      "s1=(N_s1-N_r)/N_s1\n",

-      "Z=(r1+r2/s1)+(x1+x2)*f/50.0\n",

-      "V=360\n",

-      "I1=V/Z    \n",

-      "print(\"source current=%.3f A \" %math.degrees(math.atan(I1.imag/I1.real)))\n",

-      "print(\"and with %.1f deg phase\" %math.fabs(I1))\n",

-      "I2=V/Z\n",

-      "T_e=(3/w_s)*abs(I2)**2*r2/s1    \n",

-      "print(\"motor torque=%.2f Nm\" %T_e)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "source current=0.000 A \n",

-        "and with 29.0 deg phase\n",

-        "motor torque=160.46 Nm\n",

-        "source current=-0.000 A \n",

-        "and with 142.9 deg phase\n",

-        "motor torque=-2598.45 Nm\n"

-       ]

-      }

-     ],

-     "prompt_number": 37

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Power_Electronics/Chapter13.ipynb b/_Power_Electronics/Chapter13.ipynb
deleted file mode 100755
index 62d2a926..00000000
--- a/_Power_Electronics/Chapter13.ipynb
+++ /dev/null
@@ -1,342 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 13 : Power Factor Improvement"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 13.1, Page No 754"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=250.0\n",

-      "R_l=5.0\n",

-      "I_l=20.0\n",

-      "V_l1=math.sqrt(V_s**2-(R_l*I_l)**2)\n",

-      "reg2=(V_s-V_l1)/V_s*100    \n",

-      "pf1=1.0\n",

-      "\n",

-      "#Calculations\n",

-      "P_l1=V_l1*I_l*pf1     #load power\n",

-      "P_r1=V_s*I_l*pf1     #max powwible system rating\n",

-      "utf1=P_l1*100/P_r1  \n",

-      "pf2=0.5\n",

-      " #(.5*V_l)**2+(.866*V_l+R_l*I_l)**2=V_s**2\n",

-      " #after solving\n",

-      "V_l2=158.35    \n",

-      "reg2=(V_s-V_l2)/V_s*100    \n",

-      "P_l2=V_l2*I_l*pf2   #load power\n",

-      "P_r2=V_s*I_l     #max powwible system rating\n",

-      "utf2=P_l2*100/P_r2    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"for pf=1\")\n",

-      "print(\"load voltage=%.2f V\" %V_l1)\n",

-      "print(\"voltage regulation=%.2f\" %reg1)\n",

-      "print(\"system utilisation factor=%.3f\" %utf1)\n",

-      "print(\"energy consumed(in units)=%.1f\" %(P_l1/1000))\n",

-      "print(\"for pf=.5\")\n",

-      "print(\"load voltage=%.2f V\" %V_l2)\n",

-      "print(\"voltage regulation=%.2f\" %reg2)\n",

-      "print(\"system utilisation factor=%.3f\" %utf2)\n",

-      "print(\"energy consumed(in units)=%.2f\" %(P_l2/1000))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "ename": "NameError",

-       "evalue": "name 'reg1' is not defined",

-       "output_type": "pyerr",

-       "traceback": [

-        "\u001b[1;31m---------------------------------------------------------------------------\u001b[0m\n\u001b[1;31mNameError\u001b[0m                                 Traceback (most recent call last)",

-        "\u001b[1;32m<ipython-input-2-ffdbe43fd921>\u001b[0m in \u001b[0;36m<module>\u001b[1;34m()\u001b[0m\n\u001b[0;32m     25\u001b[0m \u001b[1;32mprint\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;34m\"for pf=1\"\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0;32m     26\u001b[0m \u001b[1;32mprint\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;34m\"load voltage=%.2f V\"\u001b[0m \u001b[1;33m%\u001b[0m\u001b[0mV_l1\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[1;32m---> 27\u001b[1;33m \u001b[1;32mprint\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;34m\"voltage regulation=%.2f\"\u001b[0m \u001b[1;33m%\u001b[0m\u001b[0mreg1\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0m\u001b[0;32m     28\u001b[0m \u001b[1;32mprint\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;34m\"system utilisation factor=%.3f\"\u001b[0m \u001b[1;33m%\u001b[0m\u001b[0mutf1\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0;32m     29\u001b[0m \u001b[1;32mprint\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;34m\"energy consumed(in units)=%.1f\"\u001b[0m \u001b[1;33m%\u001b[0m\u001b[1;33m(\u001b[0m\u001b[0mP_l1\u001b[0m\u001b[1;33m/\u001b[0m\u001b[1;36m1000\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n",

-        "\u001b[1;31mNameError\u001b[0m: name 'reg1' is not defined"

-       ]

-      },

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for pf=1\n",

-        "load voltage=229.13 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 2

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 13.2, Page No 756"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "f=50.0\n",

-      "V_s=230.0\n",

-      "I_m1=2\n",

-      "pf1=.3\n",

-      "\n",

-      "#Calculations\n",

-      "I_c1=I_m1*math.sin(math.radians(math.degrees(math.acos(pf1))))\n",

-      "C1=I_c1/(2*math.pi*f*V_s)    \n",

-      "I_m2=5\n",

-      "pf2=.5\n",

-      "I_c2=I_m2*math.sin(math.radians(math.degrees(math.acos(pf2))))\n",

-      "C2=I_c2/(2*math.pi*f*V_s)    \n",

-      "I_m3=10\n",

-      "pf3=.7\n",

-      "I_c3=I_m3*math.sin(math.radians(math.degrees(math.acos(pf3))))\n",

-      "C3=I_c3/(2*math.pi*f*V_s)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"at no load\")\n",

-      "print(\"value of capacitance=%.3f uF\" %(C1*10**6))\n",

-      "print(\"at half full load\")\n",

-      "print(\"value of capacitance=%.3f uF\" %(C2*10**6))\n",

-      "print(\"at full load\")\n",

-      "print(\"value of capacitance=%.3f uF\" %(C3*10**6))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "at no load\n",

-        "value of capacitance=26.404 uF\n",

-        "at half full load\n",

-        "value of capacitance=59.927 uF\n",

-        "at full load\n",

-        "value of capacitance=98.834 uF\n"

-       ]

-      }

-     ],

-     "prompt_number": 3

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 13.3 Page No 764"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "I_c=10.0\n",

-      "f=50.0\n",

-      "V_s=230.0\n",

-      "\n",

-      "#Calculations\n",

-      "C=I_c/(2*math.pi*f*V_s)    \n",

-      "I_l=10\n",

-      "L=V_s/(2*math.pi*f*I_l)   \n",

-      "\n",

-      "#Results\n",

-      "print(\"value of capacitance=%.3f uF\" %(C*10**6))\n",

-      "print(\"value of inductor=%.3f mH\" %(L*1000))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "value of capacitance=138.396 uF\n",

-        "value of inductor=73.211 mH\n"

-       ]

-      }

-     ],

-     "prompt_number": 4

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 13.4, Page No 765"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "I_L=10.0\n",

-      "X_L=V_s/I_L\n",

-      "I_f1=6.0\n",

-      " #B=2*a-math.sin(2*a)\n",

-      "B=2*math.pi-I_f1*math.pi*X_L/V_s\n",

-      "a=0\n",

-      "i=1.0\n",

-      "for a in range(1,360):\n",

-      "    b=2*a*math.pi/180-math.sin(math.radians(2*a))   \n",

-      "    if math.fabs(B-b)<=0.001  :      #by hit and trial\n",

-      "        i=2\n",

-      "        break\n",

-      "print(\"firing angle of TCR = %.1f deg\" %a)\n",

-      " #(a-.01)*180/math.pi)\n",

-      " \n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "firing angle of TCR = 359.0 deg\n"

-       ]

-      }

-     ],

-     "prompt_number": 5

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 13.5 Page No 766"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "L=.01\n",

-      "\n",

-      "\n",

-      "#Calculations\n",

-      "print(\"for firing angle=90deg\")\n",

-      "a=90*math.pi/180\n",

-      "L_eff=math.pi*L/(2*math.pi-2*a+math.sin(2*a))    \n",

-      "print(\"effective inductance=%.0f mH\" %(L_eff*1000))\n",

-      "print(\"for firing angle=120deg\")\n",

-      "a=120*math.pi/180\n",

-      "L_eff=math.pi*L/(2*math.pi-2*a+math.sin(2*a))    \n",

-      "print(\"effective inductance=%.3f mH\" %(L_eff*1000))\n",

-      "print(\"for firing angle=150deg\")\n",

-      "a=150*math.pi/180\n",

-      "L_eff=math.pi*L/(2*math.pi-2*a+math.sin(2*a))    \n",

-      "print(\"effective inductance=%.2f mH\" %(L_eff*1000))\n",

-      "print(\"for firing angle=170deg\")\n",

-      "a=170*math.pi/180\n",

-      "L_eff=math.pi*L/(2*math.pi-2*a+math.sin(2*a))    \n",

-      "print(\"effective inductance=%.3f H\" %L_eff)\n",

-      "print(\"for firing angle=175deg\")\n",

-      "a=175*math.pi/180\n",

-      "L_eff=math.pi*L/(2*math.pi-2*a+math.sin(2*a))  \n",

-      "\n",

-      "#Results\n",

-      "print(\"effective inductance=%.2f H\" %L_eff)\n",

-      "print(\"for firing angle=180deg\")\n",

-      "a=180*math.pi/180\n",

-      "L_eff=math.pi*L/(2*math.pi-2*a+math.sin(2*a))    \n",

-      "print(\"effective inductance=%.3f H\" %L_eff)\n",

-      " #random value at firing angle =180 is equivalent to infinity as in answer in book\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for firing angle=90deg\n",

-        "effective inductance=10 mH\n",

-        "for firing angle=120deg\n",

-        "effective inductance=25.575 mH\n",

-        "for firing angle=150deg\n",

-        "effective inductance=173.40 mH\n",

-        "for firing angle=170deg\n",

-        "effective inductance=4.459 H\n",

-        "for firing angle=175deg\n",

-        "effective inductance=35.51 H\n",

-        "for firing angle=180deg\n",

-        "effective inductance=-128265253940037.750 H\n"

-       ]

-      }

-     ],

-     "prompt_number": 6

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 13.6 Page No 766"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "Q=100.0*10**3\n",

-      "V_s=11.0*10**3\n",

-      "\n",

-      "#Calculations\n",

-      "f=50.0\n",

-      "L=V_s**2/(2*math.pi*f*Q)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"effective inductance=%.4f H\" %L)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "effective inductance=3.8515 H\n"

-       ]

-      }

-     ],

-     "prompt_number": 7

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Power_Electronics/Chapter13_1.ipynb b/_Power_Electronics/Chapter13_1.ipynb
deleted file mode 100755
index 62d2a926..00000000
--- a/_Power_Electronics/Chapter13_1.ipynb
+++ /dev/null
@@ -1,342 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 13 : Power Factor Improvement"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 13.1, Page No 754"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=250.0\n",

-      "R_l=5.0\n",

-      "I_l=20.0\n",

-      "V_l1=math.sqrt(V_s**2-(R_l*I_l)**2)\n",

-      "reg2=(V_s-V_l1)/V_s*100    \n",

-      "pf1=1.0\n",

-      "\n",

-      "#Calculations\n",

-      "P_l1=V_l1*I_l*pf1     #load power\n",

-      "P_r1=V_s*I_l*pf1     #max powwible system rating\n",

-      "utf1=P_l1*100/P_r1  \n",

-      "pf2=0.5\n",

-      " #(.5*V_l)**2+(.866*V_l+R_l*I_l)**2=V_s**2\n",

-      " #after solving\n",

-      "V_l2=158.35    \n",

-      "reg2=(V_s-V_l2)/V_s*100    \n",

-      "P_l2=V_l2*I_l*pf2   #load power\n",

-      "P_r2=V_s*I_l     #max powwible system rating\n",

-      "utf2=P_l2*100/P_r2    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"for pf=1\")\n",

-      "print(\"load voltage=%.2f V\" %V_l1)\n",

-      "print(\"voltage regulation=%.2f\" %reg1)\n",

-      "print(\"system utilisation factor=%.3f\" %utf1)\n",

-      "print(\"energy consumed(in units)=%.1f\" %(P_l1/1000))\n",

-      "print(\"for pf=.5\")\n",

-      "print(\"load voltage=%.2f V\" %V_l2)\n",

-      "print(\"voltage regulation=%.2f\" %reg2)\n",

-      "print(\"system utilisation factor=%.3f\" %utf2)\n",

-      "print(\"energy consumed(in units)=%.2f\" %(P_l2/1000))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "ename": "NameError",

-       "evalue": "name 'reg1' is not defined",

-       "output_type": "pyerr",

-       "traceback": [

-        "\u001b[1;31m---------------------------------------------------------------------------\u001b[0m\n\u001b[1;31mNameError\u001b[0m                                 Traceback (most recent call last)",

-        "\u001b[1;32m<ipython-input-2-ffdbe43fd921>\u001b[0m in \u001b[0;36m<module>\u001b[1;34m()\u001b[0m\n\u001b[0;32m     25\u001b[0m \u001b[1;32mprint\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;34m\"for pf=1\"\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0;32m     26\u001b[0m \u001b[1;32mprint\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;34m\"load voltage=%.2f V\"\u001b[0m \u001b[1;33m%\u001b[0m\u001b[0mV_l1\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[1;32m---> 27\u001b[1;33m \u001b[1;32mprint\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;34m\"voltage regulation=%.2f\"\u001b[0m \u001b[1;33m%\u001b[0m\u001b[0mreg1\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0m\u001b[0;32m     28\u001b[0m \u001b[1;32mprint\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;34m\"system utilisation factor=%.3f\"\u001b[0m \u001b[1;33m%\u001b[0m\u001b[0mutf1\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0;32m     29\u001b[0m \u001b[1;32mprint\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;34m\"energy consumed(in units)=%.1f\"\u001b[0m \u001b[1;33m%\u001b[0m\u001b[1;33m(\u001b[0m\u001b[0mP_l1\u001b[0m\u001b[1;33m/\u001b[0m\u001b[1;36m1000\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n",

-        "\u001b[1;31mNameError\u001b[0m: name 'reg1' is not defined"

-       ]

-      },

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for pf=1\n",

-        "load voltage=229.13 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 2

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 13.2, Page No 756"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "f=50.0\n",

-      "V_s=230.0\n",

-      "I_m1=2\n",

-      "pf1=.3\n",

-      "\n",

-      "#Calculations\n",

-      "I_c1=I_m1*math.sin(math.radians(math.degrees(math.acos(pf1))))\n",

-      "C1=I_c1/(2*math.pi*f*V_s)    \n",

-      "I_m2=5\n",

-      "pf2=.5\n",

-      "I_c2=I_m2*math.sin(math.radians(math.degrees(math.acos(pf2))))\n",

-      "C2=I_c2/(2*math.pi*f*V_s)    \n",

-      "I_m3=10\n",

-      "pf3=.7\n",

-      "I_c3=I_m3*math.sin(math.radians(math.degrees(math.acos(pf3))))\n",

-      "C3=I_c3/(2*math.pi*f*V_s)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"at no load\")\n",

-      "print(\"value of capacitance=%.3f uF\" %(C1*10**6))\n",

-      "print(\"at half full load\")\n",

-      "print(\"value of capacitance=%.3f uF\" %(C2*10**6))\n",

-      "print(\"at full load\")\n",

-      "print(\"value of capacitance=%.3f uF\" %(C3*10**6))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "at no load\n",

-        "value of capacitance=26.404 uF\n",

-        "at half full load\n",

-        "value of capacitance=59.927 uF\n",

-        "at full load\n",

-        "value of capacitance=98.834 uF\n"

-       ]

-      }

-     ],

-     "prompt_number": 3

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 13.3 Page No 764"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "I_c=10.0\n",

-      "f=50.0\n",

-      "V_s=230.0\n",

-      "\n",

-      "#Calculations\n",

-      "C=I_c/(2*math.pi*f*V_s)    \n",

-      "I_l=10\n",

-      "L=V_s/(2*math.pi*f*I_l)   \n",

-      "\n",

-      "#Results\n",

-      "print(\"value of capacitance=%.3f uF\" %(C*10**6))\n",

-      "print(\"value of inductor=%.3f mH\" %(L*1000))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "value of capacitance=138.396 uF\n",

-        "value of inductor=73.211 mH\n"

-       ]

-      }

-     ],

-     "prompt_number": 4

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 13.4, Page No 765"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "I_L=10.0\n",

-      "X_L=V_s/I_L\n",

-      "I_f1=6.0\n",

-      " #B=2*a-math.sin(2*a)\n",

-      "B=2*math.pi-I_f1*math.pi*X_L/V_s\n",

-      "a=0\n",

-      "i=1.0\n",

-      "for a in range(1,360):\n",

-      "    b=2*a*math.pi/180-math.sin(math.radians(2*a))   \n",

-      "    if math.fabs(B-b)<=0.001  :      #by hit and trial\n",

-      "        i=2\n",

-      "        break\n",

-      "print(\"firing angle of TCR = %.1f deg\" %a)\n",

-      " #(a-.01)*180/math.pi)\n",

-      " \n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "firing angle of TCR = 359.0 deg\n"

-       ]

-      }

-     ],

-     "prompt_number": 5

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 13.5 Page No 766"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "L=.01\n",

-      "\n",

-      "\n",

-      "#Calculations\n",

-      "print(\"for firing angle=90deg\")\n",

-      "a=90*math.pi/180\n",

-      "L_eff=math.pi*L/(2*math.pi-2*a+math.sin(2*a))    \n",

-      "print(\"effective inductance=%.0f mH\" %(L_eff*1000))\n",

-      "print(\"for firing angle=120deg\")\n",

-      "a=120*math.pi/180\n",

-      "L_eff=math.pi*L/(2*math.pi-2*a+math.sin(2*a))    \n",

-      "print(\"effective inductance=%.3f mH\" %(L_eff*1000))\n",

-      "print(\"for firing angle=150deg\")\n",

-      "a=150*math.pi/180\n",

-      "L_eff=math.pi*L/(2*math.pi-2*a+math.sin(2*a))    \n",

-      "print(\"effective inductance=%.2f mH\" %(L_eff*1000))\n",

-      "print(\"for firing angle=170deg\")\n",

-      "a=170*math.pi/180\n",

-      "L_eff=math.pi*L/(2*math.pi-2*a+math.sin(2*a))    \n",

-      "print(\"effective inductance=%.3f H\" %L_eff)\n",

-      "print(\"for firing angle=175deg\")\n",

-      "a=175*math.pi/180\n",

-      "L_eff=math.pi*L/(2*math.pi-2*a+math.sin(2*a))  \n",

-      "\n",

-      "#Results\n",

-      "print(\"effective inductance=%.2f H\" %L_eff)\n",

-      "print(\"for firing angle=180deg\")\n",

-      "a=180*math.pi/180\n",

-      "L_eff=math.pi*L/(2*math.pi-2*a+math.sin(2*a))    \n",

-      "print(\"effective inductance=%.3f H\" %L_eff)\n",

-      " #random value at firing angle =180 is equivalent to infinity as in answer in book\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for firing angle=90deg\n",

-        "effective inductance=10 mH\n",

-        "for firing angle=120deg\n",

-        "effective inductance=25.575 mH\n",

-        "for firing angle=150deg\n",

-        "effective inductance=173.40 mH\n",

-        "for firing angle=170deg\n",

-        "effective inductance=4.459 H\n",

-        "for firing angle=175deg\n",

-        "effective inductance=35.51 H\n",

-        "for firing angle=180deg\n",

-        "effective inductance=-128265253940037.750 H\n"

-       ]

-      }

-     ],

-     "prompt_number": 6

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 13.6 Page No 766"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "Q=100.0*10**3\n",

-      "V_s=11.0*10**3\n",

-      "\n",

-      "#Calculations\n",

-      "f=50.0\n",

-      "L=V_s**2/(2*math.pi*f*Q)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"effective inductance=%.4f H\" %L)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "effective inductance=3.8515 H\n"

-       ]

-      }

-     ],

-     "prompt_number": 7

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Power_Electronics/Chapter13_2.ipynb b/_Power_Electronics/Chapter13_2.ipynb
deleted file mode 100755
index 62d2a926..00000000
--- a/_Power_Electronics/Chapter13_2.ipynb
+++ /dev/null
@@ -1,342 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 13 : Power Factor Improvement"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 13.1, Page No 754"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=250.0\n",

-      "R_l=5.0\n",

-      "I_l=20.0\n",

-      "V_l1=math.sqrt(V_s**2-(R_l*I_l)**2)\n",

-      "reg2=(V_s-V_l1)/V_s*100    \n",

-      "pf1=1.0\n",

-      "\n",

-      "#Calculations\n",

-      "P_l1=V_l1*I_l*pf1     #load power\n",

-      "P_r1=V_s*I_l*pf1     #max powwible system rating\n",

-      "utf1=P_l1*100/P_r1  \n",

-      "pf2=0.5\n",

-      " #(.5*V_l)**2+(.866*V_l+R_l*I_l)**2=V_s**2\n",

-      " #after solving\n",

-      "V_l2=158.35    \n",

-      "reg2=(V_s-V_l2)/V_s*100    \n",

-      "P_l2=V_l2*I_l*pf2   #load power\n",

-      "P_r2=V_s*I_l     #max powwible system rating\n",

-      "utf2=P_l2*100/P_r2    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"for pf=1\")\n",

-      "print(\"load voltage=%.2f V\" %V_l1)\n",

-      "print(\"voltage regulation=%.2f\" %reg1)\n",

-      "print(\"system utilisation factor=%.3f\" %utf1)\n",

-      "print(\"energy consumed(in units)=%.1f\" %(P_l1/1000))\n",

-      "print(\"for pf=.5\")\n",

-      "print(\"load voltage=%.2f V\" %V_l2)\n",

-      "print(\"voltage regulation=%.2f\" %reg2)\n",

-      "print(\"system utilisation factor=%.3f\" %utf2)\n",

-      "print(\"energy consumed(in units)=%.2f\" %(P_l2/1000))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "ename": "NameError",

-       "evalue": "name 'reg1' is not defined",

-       "output_type": "pyerr",

-       "traceback": [

-        "\u001b[1;31m---------------------------------------------------------------------------\u001b[0m\n\u001b[1;31mNameError\u001b[0m                                 Traceback (most recent call last)",

-        "\u001b[1;32m<ipython-input-2-ffdbe43fd921>\u001b[0m in \u001b[0;36m<module>\u001b[1;34m()\u001b[0m\n\u001b[0;32m     25\u001b[0m \u001b[1;32mprint\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;34m\"for pf=1\"\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0;32m     26\u001b[0m \u001b[1;32mprint\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;34m\"load voltage=%.2f V\"\u001b[0m \u001b[1;33m%\u001b[0m\u001b[0mV_l1\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[1;32m---> 27\u001b[1;33m \u001b[1;32mprint\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;34m\"voltage regulation=%.2f\"\u001b[0m \u001b[1;33m%\u001b[0m\u001b[0mreg1\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0m\u001b[0;32m     28\u001b[0m \u001b[1;32mprint\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;34m\"system utilisation factor=%.3f\"\u001b[0m \u001b[1;33m%\u001b[0m\u001b[0mutf1\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0;32m     29\u001b[0m \u001b[1;32mprint\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;34m\"energy consumed(in units)=%.1f\"\u001b[0m \u001b[1;33m%\u001b[0m\u001b[1;33m(\u001b[0m\u001b[0mP_l1\u001b[0m\u001b[1;33m/\u001b[0m\u001b[1;36m1000\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n",

-        "\u001b[1;31mNameError\u001b[0m: name 'reg1' is not defined"

-       ]

-      },

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for pf=1\n",

-        "load voltage=229.13 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 2

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 13.2, Page No 756"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "f=50.0\n",

-      "V_s=230.0\n",

-      "I_m1=2\n",

-      "pf1=.3\n",

-      "\n",

-      "#Calculations\n",

-      "I_c1=I_m1*math.sin(math.radians(math.degrees(math.acos(pf1))))\n",

-      "C1=I_c1/(2*math.pi*f*V_s)    \n",

-      "I_m2=5\n",

-      "pf2=.5\n",

-      "I_c2=I_m2*math.sin(math.radians(math.degrees(math.acos(pf2))))\n",

-      "C2=I_c2/(2*math.pi*f*V_s)    \n",

-      "I_m3=10\n",

-      "pf3=.7\n",

-      "I_c3=I_m3*math.sin(math.radians(math.degrees(math.acos(pf3))))\n",

-      "C3=I_c3/(2*math.pi*f*V_s)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"at no load\")\n",

-      "print(\"value of capacitance=%.3f uF\" %(C1*10**6))\n",

-      "print(\"at half full load\")\n",

-      "print(\"value of capacitance=%.3f uF\" %(C2*10**6))\n",

-      "print(\"at full load\")\n",

-      "print(\"value of capacitance=%.3f uF\" %(C3*10**6))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "at no load\n",

-        "value of capacitance=26.404 uF\n",

-        "at half full load\n",

-        "value of capacitance=59.927 uF\n",

-        "at full load\n",

-        "value of capacitance=98.834 uF\n"

-       ]

-      }

-     ],

-     "prompt_number": 3

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 13.3 Page No 764"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "I_c=10.0\n",

-      "f=50.0\n",

-      "V_s=230.0\n",

-      "\n",

-      "#Calculations\n",

-      "C=I_c/(2*math.pi*f*V_s)    \n",

-      "I_l=10\n",

-      "L=V_s/(2*math.pi*f*I_l)   \n",

-      "\n",

-      "#Results\n",

-      "print(\"value of capacitance=%.3f uF\" %(C*10**6))\n",

-      "print(\"value of inductor=%.3f mH\" %(L*1000))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "value of capacitance=138.396 uF\n",

-        "value of inductor=73.211 mH\n"

-       ]

-      }

-     ],

-     "prompt_number": 4

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 13.4, Page No 765"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "I_L=10.0\n",

-      "X_L=V_s/I_L\n",

-      "I_f1=6.0\n",

-      " #B=2*a-math.sin(2*a)\n",

-      "B=2*math.pi-I_f1*math.pi*X_L/V_s\n",

-      "a=0\n",

-      "i=1.0\n",

-      "for a in range(1,360):\n",

-      "    b=2*a*math.pi/180-math.sin(math.radians(2*a))   \n",

-      "    if math.fabs(B-b)<=0.001  :      #by hit and trial\n",

-      "        i=2\n",

-      "        break\n",

-      "print(\"firing angle of TCR = %.1f deg\" %a)\n",

-      " #(a-.01)*180/math.pi)\n",

-      " \n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "firing angle of TCR = 359.0 deg\n"

-       ]

-      }

-     ],

-     "prompt_number": 5

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 13.5 Page No 766"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "L=.01\n",

-      "\n",

-      "\n",

-      "#Calculations\n",

-      "print(\"for firing angle=90deg\")\n",

-      "a=90*math.pi/180\n",

-      "L_eff=math.pi*L/(2*math.pi-2*a+math.sin(2*a))    \n",

-      "print(\"effective inductance=%.0f mH\" %(L_eff*1000))\n",

-      "print(\"for firing angle=120deg\")\n",

-      "a=120*math.pi/180\n",

-      "L_eff=math.pi*L/(2*math.pi-2*a+math.sin(2*a))    \n",

-      "print(\"effective inductance=%.3f mH\" %(L_eff*1000))\n",

-      "print(\"for firing angle=150deg\")\n",

-      "a=150*math.pi/180\n",

-      "L_eff=math.pi*L/(2*math.pi-2*a+math.sin(2*a))    \n",

-      "print(\"effective inductance=%.2f mH\" %(L_eff*1000))\n",

-      "print(\"for firing angle=170deg\")\n",

-      "a=170*math.pi/180\n",

-      "L_eff=math.pi*L/(2*math.pi-2*a+math.sin(2*a))    \n",

-      "print(\"effective inductance=%.3f H\" %L_eff)\n",

-      "print(\"for firing angle=175deg\")\n",

-      "a=175*math.pi/180\n",

-      "L_eff=math.pi*L/(2*math.pi-2*a+math.sin(2*a))  \n",

-      "\n",

-      "#Results\n",

-      "print(\"effective inductance=%.2f H\" %L_eff)\n",

-      "print(\"for firing angle=180deg\")\n",

-      "a=180*math.pi/180\n",

-      "L_eff=math.pi*L/(2*math.pi-2*a+math.sin(2*a))    \n",

-      "print(\"effective inductance=%.3f H\" %L_eff)\n",

-      " #random value at firing angle =180 is equivalent to infinity as in answer in book\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for firing angle=90deg\n",

-        "effective inductance=10 mH\n",

-        "for firing angle=120deg\n",

-        "effective inductance=25.575 mH\n",

-        "for firing angle=150deg\n",

-        "effective inductance=173.40 mH\n",

-        "for firing angle=170deg\n",

-        "effective inductance=4.459 H\n",

-        "for firing angle=175deg\n",

-        "effective inductance=35.51 H\n",

-        "for firing angle=180deg\n",

-        "effective inductance=-128265253940037.750 H\n"

-       ]

-      }

-     ],

-     "prompt_number": 6

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 13.6 Page No 766"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "Q=100.0*10**3\n",

-      "V_s=11.0*10**3\n",

-      "\n",

-      "#Calculations\n",

-      "f=50.0\n",

-      "L=V_s**2/(2*math.pi*f*Q)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"effective inductance=%.4f H\" %L)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "effective inductance=3.8515 H\n"

-       ]

-      }

-     ],

-     "prompt_number": 7

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Power_Electronics/Chapter13_3.ipynb b/_Power_Electronics/Chapter13_3.ipynb
deleted file mode 100755
index 62d2a926..00000000
--- a/_Power_Electronics/Chapter13_3.ipynb
+++ /dev/null
@@ -1,342 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 13 : Power Factor Improvement"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 13.1, Page No 754"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=250.0\n",

-      "R_l=5.0\n",

-      "I_l=20.0\n",

-      "V_l1=math.sqrt(V_s**2-(R_l*I_l)**2)\n",

-      "reg2=(V_s-V_l1)/V_s*100    \n",

-      "pf1=1.0\n",

-      "\n",

-      "#Calculations\n",

-      "P_l1=V_l1*I_l*pf1     #load power\n",

-      "P_r1=V_s*I_l*pf1     #max powwible system rating\n",

-      "utf1=P_l1*100/P_r1  \n",

-      "pf2=0.5\n",

-      " #(.5*V_l)**2+(.866*V_l+R_l*I_l)**2=V_s**2\n",

-      " #after solving\n",

-      "V_l2=158.35    \n",

-      "reg2=(V_s-V_l2)/V_s*100    \n",

-      "P_l2=V_l2*I_l*pf2   #load power\n",

-      "P_r2=V_s*I_l     #max powwible system rating\n",

-      "utf2=P_l2*100/P_r2    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"for pf=1\")\n",

-      "print(\"load voltage=%.2f V\" %V_l1)\n",

-      "print(\"voltage regulation=%.2f\" %reg1)\n",

-      "print(\"system utilisation factor=%.3f\" %utf1)\n",

-      "print(\"energy consumed(in units)=%.1f\" %(P_l1/1000))\n",

-      "print(\"for pf=.5\")\n",

-      "print(\"load voltage=%.2f V\" %V_l2)\n",

-      "print(\"voltage regulation=%.2f\" %reg2)\n",

-      "print(\"system utilisation factor=%.3f\" %utf2)\n",

-      "print(\"energy consumed(in units)=%.2f\" %(P_l2/1000))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "ename": "NameError",

-       "evalue": "name 'reg1' is not defined",

-       "output_type": "pyerr",

-       "traceback": [

-        "\u001b[1;31m---------------------------------------------------------------------------\u001b[0m\n\u001b[1;31mNameError\u001b[0m                                 Traceback (most recent call last)",

-        "\u001b[1;32m<ipython-input-2-ffdbe43fd921>\u001b[0m in \u001b[0;36m<module>\u001b[1;34m()\u001b[0m\n\u001b[0;32m     25\u001b[0m \u001b[1;32mprint\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;34m\"for pf=1\"\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0;32m     26\u001b[0m \u001b[1;32mprint\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;34m\"load voltage=%.2f V\"\u001b[0m \u001b[1;33m%\u001b[0m\u001b[0mV_l1\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[1;32m---> 27\u001b[1;33m \u001b[1;32mprint\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;34m\"voltage regulation=%.2f\"\u001b[0m \u001b[1;33m%\u001b[0m\u001b[0mreg1\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0m\u001b[0;32m     28\u001b[0m \u001b[1;32mprint\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;34m\"system utilisation factor=%.3f\"\u001b[0m \u001b[1;33m%\u001b[0m\u001b[0mutf1\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0;32m     29\u001b[0m \u001b[1;32mprint\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;34m\"energy consumed(in units)=%.1f\"\u001b[0m \u001b[1;33m%\u001b[0m\u001b[1;33m(\u001b[0m\u001b[0mP_l1\u001b[0m\u001b[1;33m/\u001b[0m\u001b[1;36m1000\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n",

-        "\u001b[1;31mNameError\u001b[0m: name 'reg1' is not defined"

-       ]

-      },

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for pf=1\n",

-        "load voltage=229.13 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 2

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 13.2, Page No 756"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "f=50.0\n",

-      "V_s=230.0\n",

-      "I_m1=2\n",

-      "pf1=.3\n",

-      "\n",

-      "#Calculations\n",

-      "I_c1=I_m1*math.sin(math.radians(math.degrees(math.acos(pf1))))\n",

-      "C1=I_c1/(2*math.pi*f*V_s)    \n",

-      "I_m2=5\n",

-      "pf2=.5\n",

-      "I_c2=I_m2*math.sin(math.radians(math.degrees(math.acos(pf2))))\n",

-      "C2=I_c2/(2*math.pi*f*V_s)    \n",

-      "I_m3=10\n",

-      "pf3=.7\n",

-      "I_c3=I_m3*math.sin(math.radians(math.degrees(math.acos(pf3))))\n",

-      "C3=I_c3/(2*math.pi*f*V_s)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"at no load\")\n",

-      "print(\"value of capacitance=%.3f uF\" %(C1*10**6))\n",

-      "print(\"at half full load\")\n",

-      "print(\"value of capacitance=%.3f uF\" %(C2*10**6))\n",

-      "print(\"at full load\")\n",

-      "print(\"value of capacitance=%.3f uF\" %(C3*10**6))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "at no load\n",

-        "value of capacitance=26.404 uF\n",

-        "at half full load\n",

-        "value of capacitance=59.927 uF\n",

-        "at full load\n",

-        "value of capacitance=98.834 uF\n"

-       ]

-      }

-     ],

-     "prompt_number": 3

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 13.3 Page No 764"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "I_c=10.0\n",

-      "f=50.0\n",

-      "V_s=230.0\n",

-      "\n",

-      "#Calculations\n",

-      "C=I_c/(2*math.pi*f*V_s)    \n",

-      "I_l=10\n",

-      "L=V_s/(2*math.pi*f*I_l)   \n",

-      "\n",

-      "#Results\n",

-      "print(\"value of capacitance=%.3f uF\" %(C*10**6))\n",

-      "print(\"value of inductor=%.3f mH\" %(L*1000))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "value of capacitance=138.396 uF\n",

-        "value of inductor=73.211 mH\n"

-       ]

-      }

-     ],

-     "prompt_number": 4

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 13.4, Page No 765"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "I_L=10.0\n",

-      "X_L=V_s/I_L\n",

-      "I_f1=6.0\n",

-      " #B=2*a-math.sin(2*a)\n",

-      "B=2*math.pi-I_f1*math.pi*X_L/V_s\n",

-      "a=0\n",

-      "i=1.0\n",

-      "for a in range(1,360):\n",

-      "    b=2*a*math.pi/180-math.sin(math.radians(2*a))   \n",

-      "    if math.fabs(B-b)<=0.001  :      #by hit and trial\n",

-      "        i=2\n",

-      "        break\n",

-      "print(\"firing angle of TCR = %.1f deg\" %a)\n",

-      " #(a-.01)*180/math.pi)\n",

-      " \n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "firing angle of TCR = 359.0 deg\n"

-       ]

-      }

-     ],

-     "prompt_number": 5

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 13.5 Page No 766"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "L=.01\n",

-      "\n",

-      "\n",

-      "#Calculations\n",

-      "print(\"for firing angle=90deg\")\n",

-      "a=90*math.pi/180\n",

-      "L_eff=math.pi*L/(2*math.pi-2*a+math.sin(2*a))    \n",

-      "print(\"effective inductance=%.0f mH\" %(L_eff*1000))\n",

-      "print(\"for firing angle=120deg\")\n",

-      "a=120*math.pi/180\n",

-      "L_eff=math.pi*L/(2*math.pi-2*a+math.sin(2*a))    \n",

-      "print(\"effective inductance=%.3f mH\" %(L_eff*1000))\n",

-      "print(\"for firing angle=150deg\")\n",

-      "a=150*math.pi/180\n",

-      "L_eff=math.pi*L/(2*math.pi-2*a+math.sin(2*a))    \n",

-      "print(\"effective inductance=%.2f mH\" %(L_eff*1000))\n",

-      "print(\"for firing angle=170deg\")\n",

-      "a=170*math.pi/180\n",

-      "L_eff=math.pi*L/(2*math.pi-2*a+math.sin(2*a))    \n",

-      "print(\"effective inductance=%.3f H\" %L_eff)\n",

-      "print(\"for firing angle=175deg\")\n",

-      "a=175*math.pi/180\n",

-      "L_eff=math.pi*L/(2*math.pi-2*a+math.sin(2*a))  \n",

-      "\n",

-      "#Results\n",

-      "print(\"effective inductance=%.2f H\" %L_eff)\n",

-      "print(\"for firing angle=180deg\")\n",

-      "a=180*math.pi/180\n",

-      "L_eff=math.pi*L/(2*math.pi-2*a+math.sin(2*a))    \n",

-      "print(\"effective inductance=%.3f H\" %L_eff)\n",

-      " #random value at firing angle =180 is equivalent to infinity as in answer in book\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for firing angle=90deg\n",

-        "effective inductance=10 mH\n",

-        "for firing angle=120deg\n",

-        "effective inductance=25.575 mH\n",

-        "for firing angle=150deg\n",

-        "effective inductance=173.40 mH\n",

-        "for firing angle=170deg\n",

-        "effective inductance=4.459 H\n",

-        "for firing angle=175deg\n",

-        "effective inductance=35.51 H\n",

-        "for firing angle=180deg\n",

-        "effective inductance=-128265253940037.750 H\n"

-       ]

-      }

-     ],

-     "prompt_number": 6

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 13.6 Page No 766"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "Q=100.0*10**3\n",

-      "V_s=11.0*10**3\n",

-      "\n",

-      "#Calculations\n",

-      "f=50.0\n",

-      "L=V_s**2/(2*math.pi*f*Q)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"effective inductance=%.4f H\" %L)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "effective inductance=3.8515 H\n"

-       ]

-      }

-     ],

-     "prompt_number": 7

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Power_Electronics/Chapter13_4.ipynb b/_Power_Electronics/Chapter13_4.ipynb
deleted file mode 100755
index 62d2a926..00000000
--- a/_Power_Electronics/Chapter13_4.ipynb
+++ /dev/null
@@ -1,342 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 13 : Power Factor Improvement"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 13.1, Page No 754"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=250.0\n",

-      "R_l=5.0\n",

-      "I_l=20.0\n",

-      "V_l1=math.sqrt(V_s**2-(R_l*I_l)**2)\n",

-      "reg2=(V_s-V_l1)/V_s*100    \n",

-      "pf1=1.0\n",

-      "\n",

-      "#Calculations\n",

-      "P_l1=V_l1*I_l*pf1     #load power\n",

-      "P_r1=V_s*I_l*pf1     #max powwible system rating\n",

-      "utf1=P_l1*100/P_r1  \n",

-      "pf2=0.5\n",

-      " #(.5*V_l)**2+(.866*V_l+R_l*I_l)**2=V_s**2\n",

-      " #after solving\n",

-      "V_l2=158.35    \n",

-      "reg2=(V_s-V_l2)/V_s*100    \n",

-      "P_l2=V_l2*I_l*pf2   #load power\n",

-      "P_r2=V_s*I_l     #max powwible system rating\n",

-      "utf2=P_l2*100/P_r2    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"for pf=1\")\n",

-      "print(\"load voltage=%.2f V\" %V_l1)\n",

-      "print(\"voltage regulation=%.2f\" %reg1)\n",

-      "print(\"system utilisation factor=%.3f\" %utf1)\n",

-      "print(\"energy consumed(in units)=%.1f\" %(P_l1/1000))\n",

-      "print(\"for pf=.5\")\n",

-      "print(\"load voltage=%.2f V\" %V_l2)\n",

-      "print(\"voltage regulation=%.2f\" %reg2)\n",

-      "print(\"system utilisation factor=%.3f\" %utf2)\n",

-      "print(\"energy consumed(in units)=%.2f\" %(P_l2/1000))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "ename": "NameError",

-       "evalue": "name 'reg1' is not defined",

-       "output_type": "pyerr",

-       "traceback": [

-        "\u001b[1;31m---------------------------------------------------------------------------\u001b[0m\n\u001b[1;31mNameError\u001b[0m                                 Traceback (most recent call last)",

-        "\u001b[1;32m<ipython-input-2-ffdbe43fd921>\u001b[0m in \u001b[0;36m<module>\u001b[1;34m()\u001b[0m\n\u001b[0;32m     25\u001b[0m \u001b[1;32mprint\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;34m\"for pf=1\"\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0;32m     26\u001b[0m \u001b[1;32mprint\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;34m\"load voltage=%.2f V\"\u001b[0m \u001b[1;33m%\u001b[0m\u001b[0mV_l1\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[1;32m---> 27\u001b[1;33m \u001b[1;32mprint\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;34m\"voltage regulation=%.2f\"\u001b[0m \u001b[1;33m%\u001b[0m\u001b[0mreg1\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0m\u001b[0;32m     28\u001b[0m \u001b[1;32mprint\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;34m\"system utilisation factor=%.3f\"\u001b[0m \u001b[1;33m%\u001b[0m\u001b[0mutf1\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0;32m     29\u001b[0m \u001b[1;32mprint\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;34m\"energy consumed(in units)=%.1f\"\u001b[0m \u001b[1;33m%\u001b[0m\u001b[1;33m(\u001b[0m\u001b[0mP_l1\u001b[0m\u001b[1;33m/\u001b[0m\u001b[1;36m1000\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n",

-        "\u001b[1;31mNameError\u001b[0m: name 'reg1' is not defined"

-       ]

-      },

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for pf=1\n",

-        "load voltage=229.13 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 2

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 13.2, Page No 756"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "f=50.0\n",

-      "V_s=230.0\n",

-      "I_m1=2\n",

-      "pf1=.3\n",

-      "\n",

-      "#Calculations\n",

-      "I_c1=I_m1*math.sin(math.radians(math.degrees(math.acos(pf1))))\n",

-      "C1=I_c1/(2*math.pi*f*V_s)    \n",

-      "I_m2=5\n",

-      "pf2=.5\n",

-      "I_c2=I_m2*math.sin(math.radians(math.degrees(math.acos(pf2))))\n",

-      "C2=I_c2/(2*math.pi*f*V_s)    \n",

-      "I_m3=10\n",

-      "pf3=.7\n",

-      "I_c3=I_m3*math.sin(math.radians(math.degrees(math.acos(pf3))))\n",

-      "C3=I_c3/(2*math.pi*f*V_s)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"at no load\")\n",

-      "print(\"value of capacitance=%.3f uF\" %(C1*10**6))\n",

-      "print(\"at half full load\")\n",

-      "print(\"value of capacitance=%.3f uF\" %(C2*10**6))\n",

-      "print(\"at full load\")\n",

-      "print(\"value of capacitance=%.3f uF\" %(C3*10**6))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "at no load\n",

-        "value of capacitance=26.404 uF\n",

-        "at half full load\n",

-        "value of capacitance=59.927 uF\n",

-        "at full load\n",

-        "value of capacitance=98.834 uF\n"

-       ]

-      }

-     ],

-     "prompt_number": 3

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 13.3 Page No 764"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "I_c=10.0\n",

-      "f=50.0\n",

-      "V_s=230.0\n",

-      "\n",

-      "#Calculations\n",

-      "C=I_c/(2*math.pi*f*V_s)    \n",

-      "I_l=10\n",

-      "L=V_s/(2*math.pi*f*I_l)   \n",

-      "\n",

-      "#Results\n",

-      "print(\"value of capacitance=%.3f uF\" %(C*10**6))\n",

-      "print(\"value of inductor=%.3f mH\" %(L*1000))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "value of capacitance=138.396 uF\n",

-        "value of inductor=73.211 mH\n"

-       ]

-      }

-     ],

-     "prompt_number": 4

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 13.4, Page No 765"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "I_L=10.0\n",

-      "X_L=V_s/I_L\n",

-      "I_f1=6.0\n",

-      " #B=2*a-math.sin(2*a)\n",

-      "B=2*math.pi-I_f1*math.pi*X_L/V_s\n",

-      "a=0\n",

-      "i=1.0\n",

-      "for a in range(1,360):\n",

-      "    b=2*a*math.pi/180-math.sin(math.radians(2*a))   \n",

-      "    if math.fabs(B-b)<=0.001  :      #by hit and trial\n",

-      "        i=2\n",

-      "        break\n",

-      "print(\"firing angle of TCR = %.1f deg\" %a)\n",

-      " #(a-.01)*180/math.pi)\n",

-      " \n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "firing angle of TCR = 359.0 deg\n"

-       ]

-      }

-     ],

-     "prompt_number": 5

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 13.5 Page No 766"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "L=.01\n",

-      "\n",

-      "\n",

-      "#Calculations\n",

-      "print(\"for firing angle=90deg\")\n",

-      "a=90*math.pi/180\n",

-      "L_eff=math.pi*L/(2*math.pi-2*a+math.sin(2*a))    \n",

-      "print(\"effective inductance=%.0f mH\" %(L_eff*1000))\n",

-      "print(\"for firing angle=120deg\")\n",

-      "a=120*math.pi/180\n",

-      "L_eff=math.pi*L/(2*math.pi-2*a+math.sin(2*a))    \n",

-      "print(\"effective inductance=%.3f mH\" %(L_eff*1000))\n",

-      "print(\"for firing angle=150deg\")\n",

-      "a=150*math.pi/180\n",

-      "L_eff=math.pi*L/(2*math.pi-2*a+math.sin(2*a))    \n",

-      "print(\"effective inductance=%.2f mH\" %(L_eff*1000))\n",

-      "print(\"for firing angle=170deg\")\n",

-      "a=170*math.pi/180\n",

-      "L_eff=math.pi*L/(2*math.pi-2*a+math.sin(2*a))    \n",

-      "print(\"effective inductance=%.3f H\" %L_eff)\n",

-      "print(\"for firing angle=175deg\")\n",

-      "a=175*math.pi/180\n",

-      "L_eff=math.pi*L/(2*math.pi-2*a+math.sin(2*a))  \n",

-      "\n",

-      "#Results\n",

-      "print(\"effective inductance=%.2f H\" %L_eff)\n",

-      "print(\"for firing angle=180deg\")\n",

-      "a=180*math.pi/180\n",

-      "L_eff=math.pi*L/(2*math.pi-2*a+math.sin(2*a))    \n",

-      "print(\"effective inductance=%.3f H\" %L_eff)\n",

-      " #random value at firing angle =180 is equivalent to infinity as in answer in book\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for firing angle=90deg\n",

-        "effective inductance=10 mH\n",

-        "for firing angle=120deg\n",

-        "effective inductance=25.575 mH\n",

-        "for firing angle=150deg\n",

-        "effective inductance=173.40 mH\n",

-        "for firing angle=170deg\n",

-        "effective inductance=4.459 H\n",

-        "for firing angle=175deg\n",

-        "effective inductance=35.51 H\n",

-        "for firing angle=180deg\n",

-        "effective inductance=-128265253940037.750 H\n"

-       ]

-      }

-     ],

-     "prompt_number": 6

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 13.6 Page No 766"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "Q=100.0*10**3\n",

-      "V_s=11.0*10**3\n",

-      "\n",

-      "#Calculations\n",

-      "f=50.0\n",

-      "L=V_s**2/(2*math.pi*f*Q)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"effective inductance=%.4f H\" %L)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "effective inductance=3.8515 H\n"

-       ]

-      }

-     ],

-     "prompt_number": 7

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Power_Electronics/Chapter14.ipynb b/_Power_Electronics/Chapter14.ipynb
deleted file mode 100755
index a9c3a3f1..00000000
--- a/_Power_Electronics/Chapter14.ipynb
+++ /dev/null
@@ -1,93 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 14 : Miscellaneous Topics"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 14.1, Page No 777"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "a1=0\n",

-      "a2=45.0\n",

-      "\n",

-      "#Calculations\n",

-      "print(\"for two single phase series semiconvertors\")\n",

-      "V_0=V_m/math.pi*(2+math.cos(math.radians(a1))+math.cos(math.radians(a2)))    \n",

-      "print(\"avg o/p voltage=%.2f V\" %V_0)\n",

-      "V_or=V_s*math.sqrt((1/math.pi)*(4*math.pi-3*a2*math.pi/180+(3/2)*math.sin(math.radians(2*a2))))    \n",

-      "print(\"rms value of o/p voltage=%.2f V\" %V_or)\n",

-      "DF=(3+math.cos(math.radians(a2)))/(math.sqrt(2)*math.sqrt(5+3*math.cos(math.radians(a2))))    \n",

-      "print(\"DF=%.2f\" %DF)\n",

-      "PF=math.sqrt(2/math.pi)*(3+math.cos(math.radians(a2)))/math.sqrt(4*math.pi-3*a2*math.pi/180)    \n",

-      "print(\"PF=%.2f\" %PF)\n",

-      "HF=math.sqrt((math.pi*(math.pi-(3/4)*a2*math.pi/180)/(5+3*math.cos(math.radians(a2))))-1)    \n",

-      "print(\"HF=%.2f\" %HF)\n",

-      "print(\"for two single phase series full convertors\")\n",

-      "a=45.0\n",

-      "V_0=2*V_m/math.pi*(1+math.cos(math.radians(a)))    \n",

-      "print(\"avg o/p voltage=%.2f V\" %V_0)\n",

-      "V_or=2*V_s*math.sqrt((1/math.pi)*(math.pi-a2*math.pi/180+(1/2)*math.sin(math.radians(2*a2))))    \n",

-      "print(\"rms value of o/p voltage=%.2f V\" %V_or)\n",

-      "DF=math.cos(math.radians(a2/2)) \n",

-      "\n",

-      "\n",

-      "#Results   \n",

-      "print(\"DF=%.2f\" %DF)\n",

-      "PF=math.sqrt(2/(math.pi*(math.pi-a2*math.pi/180)))*(1+math.cos(math.radians(a2)))    \n",

-      "print(\"PF=%.2f\" %PF)\n",

-      "HF=math.sqrt((math.pi*(math.pi-a2*math.pi/180)/(4+4*math.cos(math.radians(a2))))-1)    \n",

-      "print(\"HF=%.2f\" %HF)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for two single phase series semiconvertors\n",

-        "avg o/p voltage=383.82 V\n",

-        "rms value of o/p voltage=434.47 V\n",

-        "DF=0.98\n",

-        "PF=0.93\n",

-        "HF=0.62\n",

-        "for two single phase series full convertors\n",

-        "avg o/p voltage=353.50 V\n",

-        "rms value of o/p voltage=398.37 V\n",

-        "DF=0.92\n",

-        "PF=0.89\n",

-        "HF=0.29\n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Power_Electronics/Chapter14_1.ipynb b/_Power_Electronics/Chapter14_1.ipynb
deleted file mode 100755
index a9c3a3f1..00000000
--- a/_Power_Electronics/Chapter14_1.ipynb
+++ /dev/null
@@ -1,93 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 14 : Miscellaneous Topics"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 14.1, Page No 777"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "a1=0\n",

-      "a2=45.0\n",

-      "\n",

-      "#Calculations\n",

-      "print(\"for two single phase series semiconvertors\")\n",

-      "V_0=V_m/math.pi*(2+math.cos(math.radians(a1))+math.cos(math.radians(a2)))    \n",

-      "print(\"avg o/p voltage=%.2f V\" %V_0)\n",

-      "V_or=V_s*math.sqrt((1/math.pi)*(4*math.pi-3*a2*math.pi/180+(3/2)*math.sin(math.radians(2*a2))))    \n",

-      "print(\"rms value of o/p voltage=%.2f V\" %V_or)\n",

-      "DF=(3+math.cos(math.radians(a2)))/(math.sqrt(2)*math.sqrt(5+3*math.cos(math.radians(a2))))    \n",

-      "print(\"DF=%.2f\" %DF)\n",

-      "PF=math.sqrt(2/math.pi)*(3+math.cos(math.radians(a2)))/math.sqrt(4*math.pi-3*a2*math.pi/180)    \n",

-      "print(\"PF=%.2f\" %PF)\n",

-      "HF=math.sqrt((math.pi*(math.pi-(3/4)*a2*math.pi/180)/(5+3*math.cos(math.radians(a2))))-1)    \n",

-      "print(\"HF=%.2f\" %HF)\n",

-      "print(\"for two single phase series full convertors\")\n",

-      "a=45.0\n",

-      "V_0=2*V_m/math.pi*(1+math.cos(math.radians(a)))    \n",

-      "print(\"avg o/p voltage=%.2f V\" %V_0)\n",

-      "V_or=2*V_s*math.sqrt((1/math.pi)*(math.pi-a2*math.pi/180+(1/2)*math.sin(math.radians(2*a2))))    \n",

-      "print(\"rms value of o/p voltage=%.2f V\" %V_or)\n",

-      "DF=math.cos(math.radians(a2/2)) \n",

-      "\n",

-      "\n",

-      "#Results   \n",

-      "print(\"DF=%.2f\" %DF)\n",

-      "PF=math.sqrt(2/(math.pi*(math.pi-a2*math.pi/180)))*(1+math.cos(math.radians(a2)))    \n",

-      "print(\"PF=%.2f\" %PF)\n",

-      "HF=math.sqrt((math.pi*(math.pi-a2*math.pi/180)/(4+4*math.cos(math.radians(a2))))-1)    \n",

-      "print(\"HF=%.2f\" %HF)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for two single phase series semiconvertors\n",

-        "avg o/p voltage=383.82 V\n",

-        "rms value of o/p voltage=434.47 V\n",

-        "DF=0.98\n",

-        "PF=0.93\n",

-        "HF=0.62\n",

-        "for two single phase series full convertors\n",

-        "avg o/p voltage=353.50 V\n",

-        "rms value of o/p voltage=398.37 V\n",

-        "DF=0.92\n",

-        "PF=0.89\n",

-        "HF=0.29\n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Power_Electronics/Chapter14_2.ipynb b/_Power_Electronics/Chapter14_2.ipynb
deleted file mode 100755
index a9c3a3f1..00000000
--- a/_Power_Electronics/Chapter14_2.ipynb
+++ /dev/null
@@ -1,93 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 14 : Miscellaneous Topics"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 14.1, Page No 777"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "a1=0\n",

-      "a2=45.0\n",

-      "\n",

-      "#Calculations\n",

-      "print(\"for two single phase series semiconvertors\")\n",

-      "V_0=V_m/math.pi*(2+math.cos(math.radians(a1))+math.cos(math.radians(a2)))    \n",

-      "print(\"avg o/p voltage=%.2f V\" %V_0)\n",

-      "V_or=V_s*math.sqrt((1/math.pi)*(4*math.pi-3*a2*math.pi/180+(3/2)*math.sin(math.radians(2*a2))))    \n",

-      "print(\"rms value of o/p voltage=%.2f V\" %V_or)\n",

-      "DF=(3+math.cos(math.radians(a2)))/(math.sqrt(2)*math.sqrt(5+3*math.cos(math.radians(a2))))    \n",

-      "print(\"DF=%.2f\" %DF)\n",

-      "PF=math.sqrt(2/math.pi)*(3+math.cos(math.radians(a2)))/math.sqrt(4*math.pi-3*a2*math.pi/180)    \n",

-      "print(\"PF=%.2f\" %PF)\n",

-      "HF=math.sqrt((math.pi*(math.pi-(3/4)*a2*math.pi/180)/(5+3*math.cos(math.radians(a2))))-1)    \n",

-      "print(\"HF=%.2f\" %HF)\n",

-      "print(\"for two single phase series full convertors\")\n",

-      "a=45.0\n",

-      "V_0=2*V_m/math.pi*(1+math.cos(math.radians(a)))    \n",

-      "print(\"avg o/p voltage=%.2f V\" %V_0)\n",

-      "V_or=2*V_s*math.sqrt((1/math.pi)*(math.pi-a2*math.pi/180+(1/2)*math.sin(math.radians(2*a2))))    \n",

-      "print(\"rms value of o/p voltage=%.2f V\" %V_or)\n",

-      "DF=math.cos(math.radians(a2/2)) \n",

-      "\n",

-      "\n",

-      "#Results   \n",

-      "print(\"DF=%.2f\" %DF)\n",

-      "PF=math.sqrt(2/(math.pi*(math.pi-a2*math.pi/180)))*(1+math.cos(math.radians(a2)))    \n",

-      "print(\"PF=%.2f\" %PF)\n",

-      "HF=math.sqrt((math.pi*(math.pi-a2*math.pi/180)/(4+4*math.cos(math.radians(a2))))-1)    \n",

-      "print(\"HF=%.2f\" %HF)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for two single phase series semiconvertors\n",

-        "avg o/p voltage=383.82 V\n",

-        "rms value of o/p voltage=434.47 V\n",

-        "DF=0.98\n",

-        "PF=0.93\n",

-        "HF=0.62\n",

-        "for two single phase series full convertors\n",

-        "avg o/p voltage=353.50 V\n",

-        "rms value of o/p voltage=398.37 V\n",

-        "DF=0.92\n",

-        "PF=0.89\n",

-        "HF=0.29\n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Power_Electronics/Chapter14_3.ipynb b/_Power_Electronics/Chapter14_3.ipynb
deleted file mode 100755
index a9c3a3f1..00000000
--- a/_Power_Electronics/Chapter14_3.ipynb
+++ /dev/null
@@ -1,93 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 14 : Miscellaneous Topics"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 14.1, Page No 777"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "a1=0\n",

-      "a2=45.0\n",

-      "\n",

-      "#Calculations\n",

-      "print(\"for two single phase series semiconvertors\")\n",

-      "V_0=V_m/math.pi*(2+math.cos(math.radians(a1))+math.cos(math.radians(a2)))    \n",

-      "print(\"avg o/p voltage=%.2f V\" %V_0)\n",

-      "V_or=V_s*math.sqrt((1/math.pi)*(4*math.pi-3*a2*math.pi/180+(3/2)*math.sin(math.radians(2*a2))))    \n",

-      "print(\"rms value of o/p voltage=%.2f V\" %V_or)\n",

-      "DF=(3+math.cos(math.radians(a2)))/(math.sqrt(2)*math.sqrt(5+3*math.cos(math.radians(a2))))    \n",

-      "print(\"DF=%.2f\" %DF)\n",

-      "PF=math.sqrt(2/math.pi)*(3+math.cos(math.radians(a2)))/math.sqrt(4*math.pi-3*a2*math.pi/180)    \n",

-      "print(\"PF=%.2f\" %PF)\n",

-      "HF=math.sqrt((math.pi*(math.pi-(3/4)*a2*math.pi/180)/(5+3*math.cos(math.radians(a2))))-1)    \n",

-      "print(\"HF=%.2f\" %HF)\n",

-      "print(\"for two single phase series full convertors\")\n",

-      "a=45.0\n",

-      "V_0=2*V_m/math.pi*(1+math.cos(math.radians(a)))    \n",

-      "print(\"avg o/p voltage=%.2f V\" %V_0)\n",

-      "V_or=2*V_s*math.sqrt((1/math.pi)*(math.pi-a2*math.pi/180+(1/2)*math.sin(math.radians(2*a2))))    \n",

-      "print(\"rms value of o/p voltage=%.2f V\" %V_or)\n",

-      "DF=math.cos(math.radians(a2/2)) \n",

-      "\n",

-      "\n",

-      "#Results   \n",

-      "print(\"DF=%.2f\" %DF)\n",

-      "PF=math.sqrt(2/(math.pi*(math.pi-a2*math.pi/180)))*(1+math.cos(math.radians(a2)))    \n",

-      "print(\"PF=%.2f\" %PF)\n",

-      "HF=math.sqrt((math.pi*(math.pi-a2*math.pi/180)/(4+4*math.cos(math.radians(a2))))-1)    \n",

-      "print(\"HF=%.2f\" %HF)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for two single phase series semiconvertors\n",

-        "avg o/p voltage=383.82 V\n",

-        "rms value of o/p voltage=434.47 V\n",

-        "DF=0.98\n",

-        "PF=0.93\n",

-        "HF=0.62\n",

-        "for two single phase series full convertors\n",

-        "avg o/p voltage=353.50 V\n",

-        "rms value of o/p voltage=398.37 V\n",

-        "DF=0.92\n",

-        "PF=0.89\n",

-        "HF=0.29\n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Power_Electronics/Chapter14_4.ipynb b/_Power_Electronics/Chapter14_4.ipynb
deleted file mode 100755
index a9c3a3f1..00000000
--- a/_Power_Electronics/Chapter14_4.ipynb
+++ /dev/null
@@ -1,93 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 14 : Miscellaneous Topics"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 14.1, Page No 777"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "a1=0\n",

-      "a2=45.0\n",

-      "\n",

-      "#Calculations\n",

-      "print(\"for two single phase series semiconvertors\")\n",

-      "V_0=V_m/math.pi*(2+math.cos(math.radians(a1))+math.cos(math.radians(a2)))    \n",

-      "print(\"avg o/p voltage=%.2f V\" %V_0)\n",

-      "V_or=V_s*math.sqrt((1/math.pi)*(4*math.pi-3*a2*math.pi/180+(3/2)*math.sin(math.radians(2*a2))))    \n",

-      "print(\"rms value of o/p voltage=%.2f V\" %V_or)\n",

-      "DF=(3+math.cos(math.radians(a2)))/(math.sqrt(2)*math.sqrt(5+3*math.cos(math.radians(a2))))    \n",

-      "print(\"DF=%.2f\" %DF)\n",

-      "PF=math.sqrt(2/math.pi)*(3+math.cos(math.radians(a2)))/math.sqrt(4*math.pi-3*a2*math.pi/180)    \n",

-      "print(\"PF=%.2f\" %PF)\n",

-      "HF=math.sqrt((math.pi*(math.pi-(3/4)*a2*math.pi/180)/(5+3*math.cos(math.radians(a2))))-1)    \n",

-      "print(\"HF=%.2f\" %HF)\n",

-      "print(\"for two single phase series full convertors\")\n",

-      "a=45.0\n",

-      "V_0=2*V_m/math.pi*(1+math.cos(math.radians(a)))    \n",

-      "print(\"avg o/p voltage=%.2f V\" %V_0)\n",

-      "V_or=2*V_s*math.sqrt((1/math.pi)*(math.pi-a2*math.pi/180+(1/2)*math.sin(math.radians(2*a2))))    \n",

-      "print(\"rms value of o/p voltage=%.2f V\" %V_or)\n",

-      "DF=math.cos(math.radians(a2/2)) \n",

-      "\n",

-      "\n",

-      "#Results   \n",

-      "print(\"DF=%.2f\" %DF)\n",

-      "PF=math.sqrt(2/(math.pi*(math.pi-a2*math.pi/180)))*(1+math.cos(math.radians(a2)))    \n",

-      "print(\"PF=%.2f\" %PF)\n",

-      "HF=math.sqrt((math.pi*(math.pi-a2*math.pi/180)/(4+4*math.cos(math.radians(a2))))-1)    \n",

-      "print(\"HF=%.2f\" %HF)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for two single phase series semiconvertors\n",

-        "avg o/p voltage=383.82 V\n",

-        "rms value of o/p voltage=434.47 V\n",

-        "DF=0.98\n",

-        "PF=0.93\n",

-        "HF=0.62\n",

-        "for two single phase series full convertors\n",

-        "avg o/p voltage=353.50 V\n",

-        "rms value of o/p voltage=398.37 V\n",

-        "DF=0.92\n",

-        "PF=0.89\n",

-        "HF=0.29\n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Power_Electronics/Chapter2.ipynb b/_Power_Electronics/Chapter2.ipynb
deleted file mode 100755
index 1872c9f4..00000000
--- a/_Power_Electronics/Chapter2.ipynb
+++ /dev/null
@@ -1,233 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 02 : Power Semiconductor Diodes and Transistors"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 2.1, Page No 21"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "B=40.0\n",

-      "R_c=10                    #ohm\n",

-      "V_cc=130.0                #V\n",

-      "V_B=10.0                  #V\n",

-      "V_CES=1.0                 #V\n",

-      "V_BES=1.5                 #V\n",

-      "\n",

-      "#Calculations\n",

-      "I_CS=(V_cc-V_CES)/R_c     #A\n",

-      "I_BS=I_CS/B                #A\n",

-      "R_B1=(V_B-V_BES)/I_BS\n",

-      "P_T1=V_BES*I_BS+V_CES*I_CS\n",

-      "ODF=5\n",

-      "I_B=ODF*I_BS\n",

-      "R_B2=(V_B-V_BES)/I_B\n",

-      "P_T2=V_BES*I_B+V_CES*I_CS\n",

-      "B_f=I_CS/I_B\n",

-      "\n",

-      "#Results\n",

-      "print(\"value of R_B in saturated state= %.2f ohm\" %R_B1)\n",

-      "print(\"Power loss in transistor=%.2f W\" %P_T1)\n",

-      "print(\"Value of R_B for an overdrive factor 5 = %.2f ohm\" %R_B2)\n",

-      "print(\"Power loss in transistor = %.2f W\" %P_T2)\n",

-      "print(\"Forced current gain=%.0f\" %B_f)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "value of R_B in saturated state= 26.36 ohm\n",

-        "Power loss in transistor=13.38 W\n",

-        "Value of R_B for an overdrive factor 5 = 5.27 ohm\n",

-        "Power loss in transistor = 15.32 W\n",

-        "Forced current gain=8\n"

-       ]

-      }

-     ],

-     "prompt_number": 5

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 2.2, Page No 24"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "I_CEO=2*10**-3            #A\n",

-      "V_CC=220.0                #V\n",

-      "P_dt=I_CEO*V_CC           #instant. power loss during delay time\n",

-      "t_d=.4*10**-6            #s\n",

-      "f=5000\n",

-      "P_d=f*I_CEO*V_CC*t_d      #avg power loss during delay time\n",

-      "V_CES=2                     #V\n",

-      "t_r=1*10**-6               #s\n",

-      "I_CS=80                    #A\n",

-      "\n",

-      "#Calculations\n",

-      "P_r=f*I_CS*t_r*(V_CC/2-(V_CC-V_CES)/3)            #avg power loss during rise time\n",

-      "t_m=V_CC*t_r/(2*(V_CC-V_CES))\n",

-      "P_rm=I_CS*V_CC**2/(4*(V_CC-V_CES))           #instant. power loss during rise time\n",

-      "\n",

-      "#Results\n",

-      "P_on=P_d+P_r                \n",

-      "print(\"Avg power loss during turn on = %.2f W\" %P_on)\n",

-      "P_nt=I_CS*V_CES \n",

-      "print(\"Instantaneous power loss during turn on = %.0f W\" %P_nt)\n",

-      "t_n=50*10**-6\n",

-      "P_n=f*I_CS*V_CES*t_n\n",

-      "print(\"Avg power loss during conduction period = %.0f W\" %P_n)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Avg power loss during turn on = 14.93 W\n",

-        "Instantaneous power loss during turn on = 160 W\n",

-        "Avg power loss during conduction period = 40 W\n"

-       ]

-      }

-     ],

-     "prompt_number": 7

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 2.3 Page No 26"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "I_CEO=2*10**-3         #A\n",

-      "V_CC=220          #V\n",

-      "t_d=.4*10**-6   #s\n",

-      "f=5000\n",

-      "V_CES=2         #V\n",

-      "t_r=1*10**-6    #s\n",

-      "I_CS=80         #A\n",

-      "t_n=50*10**-6   #s\n",

-      "t_0=40*10**-6   #s\n",

-      "t_f=3*10**-6    #s\n",

-      "\n",

-      "#Calculations\n",

-      "P_st=I_CS*V_CES  # instant. power loss during t_s\n",

-      "P_s=f*I_CS*V_CES*t_f   #avg power loss during t_s\n",

-      "P_f=f*t_f*(I_CS/6)*(V_CC-V_CES)        #avg power loss during fall time\n",

-      "P_fm=(I_CS/4)*(V_CC-V_CES)          #peak instant power dissipation\n",

-      "P_off=P_s+P_f\n",

-      "\n",

-      "#Results\n",

-      "print(\"Total avg power loss during turn off = %.2f W\" %P_off)\n",

-      "P_0t=I_CEO*V_CC\n",

-      "print(\"Instantaneous power loss during t_0 = %.2f W\" %P_0t)\n",

-      "P_0=f*I_CEO*V_CC*t_0              #avg power loss during t_s\n",

-      "P_on=14.9339              #W    from previous eg\n",

-      "P_n=40                    #W    from previous eg\n",

-      "P_T=P_on+P_n+P_off+P_0     \n",

-      "print(\"Total power loss = %.2f W\" %P_T)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Total avg power loss during turn off = 44.91 W\n",

-        "Instantaneous power loss during t_0 = 0.44 W\n",

-        "Total power loss = 99.93 W\n"

-       ]

-      }

-     ],

-     "prompt_number": 8

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 2.4, Page No 28"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "I_CS=100.0 \n",

-      "V_CC=200.0 \n",

-      "t_on=40*10**-6\n",

-      "\n",

-      "#Calculations\n",

-      "P_on=(I_CS/50)*10**6*t_on*(V_CC*t_on/2-(V_CC*10**6*t_on**2/(40*3)))       #energy during turn on\n",

-      "t_off=60*10**-6\n",

-      "P_off=(I_CS*t_off/2-(I_CS/60)*10**6*(t_off**2)/3)*((V_CC/75)*10**6*t_off)  #energy during turn off\n",

-      "P_t=P_on+P_off           #total energy\n",

-      "P_avg=300.0\n",

-      "f=P_avg/P_t\n",

-      "\n",

-      "#Results\n",

-      "print(\"Allowable switching frequency = %.2f Hz\" %f)\n",

-      "#in book ans is: f=1123.6 Hz. The difference in results due to difference in rounding of of digits"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Allowable switching frequency = 1125.00 Hz\n"

-       ]

-      }

-     ],

-     "prompt_number": 10

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Power_Electronics/Chapter2_1.ipynb b/_Power_Electronics/Chapter2_1.ipynb
deleted file mode 100755
index 1872c9f4..00000000
--- a/_Power_Electronics/Chapter2_1.ipynb
+++ /dev/null
@@ -1,233 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 02 : Power Semiconductor Diodes and Transistors"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 2.1, Page No 21"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "B=40.0\n",

-      "R_c=10                    #ohm\n",

-      "V_cc=130.0                #V\n",

-      "V_B=10.0                  #V\n",

-      "V_CES=1.0                 #V\n",

-      "V_BES=1.5                 #V\n",

-      "\n",

-      "#Calculations\n",

-      "I_CS=(V_cc-V_CES)/R_c     #A\n",

-      "I_BS=I_CS/B                #A\n",

-      "R_B1=(V_B-V_BES)/I_BS\n",

-      "P_T1=V_BES*I_BS+V_CES*I_CS\n",

-      "ODF=5\n",

-      "I_B=ODF*I_BS\n",

-      "R_B2=(V_B-V_BES)/I_B\n",

-      "P_T2=V_BES*I_B+V_CES*I_CS\n",

-      "B_f=I_CS/I_B\n",

-      "\n",

-      "#Results\n",

-      "print(\"value of R_B in saturated state= %.2f ohm\" %R_B1)\n",

-      "print(\"Power loss in transistor=%.2f W\" %P_T1)\n",

-      "print(\"Value of R_B for an overdrive factor 5 = %.2f ohm\" %R_B2)\n",

-      "print(\"Power loss in transistor = %.2f W\" %P_T2)\n",

-      "print(\"Forced current gain=%.0f\" %B_f)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "value of R_B in saturated state= 26.36 ohm\n",

-        "Power loss in transistor=13.38 W\n",

-        "Value of R_B for an overdrive factor 5 = 5.27 ohm\n",

-        "Power loss in transistor = 15.32 W\n",

-        "Forced current gain=8\n"

-       ]

-      }

-     ],

-     "prompt_number": 5

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 2.2, Page No 24"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "I_CEO=2*10**-3            #A\n",

-      "V_CC=220.0                #V\n",

-      "P_dt=I_CEO*V_CC           #instant. power loss during delay time\n",

-      "t_d=.4*10**-6            #s\n",

-      "f=5000\n",

-      "P_d=f*I_CEO*V_CC*t_d      #avg power loss during delay time\n",

-      "V_CES=2                     #V\n",

-      "t_r=1*10**-6               #s\n",

-      "I_CS=80                    #A\n",

-      "\n",

-      "#Calculations\n",

-      "P_r=f*I_CS*t_r*(V_CC/2-(V_CC-V_CES)/3)            #avg power loss during rise time\n",

-      "t_m=V_CC*t_r/(2*(V_CC-V_CES))\n",

-      "P_rm=I_CS*V_CC**2/(4*(V_CC-V_CES))           #instant. power loss during rise time\n",

-      "\n",

-      "#Results\n",

-      "P_on=P_d+P_r                \n",

-      "print(\"Avg power loss during turn on = %.2f W\" %P_on)\n",

-      "P_nt=I_CS*V_CES \n",

-      "print(\"Instantaneous power loss during turn on = %.0f W\" %P_nt)\n",

-      "t_n=50*10**-6\n",

-      "P_n=f*I_CS*V_CES*t_n\n",

-      "print(\"Avg power loss during conduction period = %.0f W\" %P_n)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Avg power loss during turn on = 14.93 W\n",

-        "Instantaneous power loss during turn on = 160 W\n",

-        "Avg power loss during conduction period = 40 W\n"

-       ]

-      }

-     ],

-     "prompt_number": 7

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 2.3 Page No 26"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "I_CEO=2*10**-3         #A\n",

-      "V_CC=220          #V\n",

-      "t_d=.4*10**-6   #s\n",

-      "f=5000\n",

-      "V_CES=2         #V\n",

-      "t_r=1*10**-6    #s\n",

-      "I_CS=80         #A\n",

-      "t_n=50*10**-6   #s\n",

-      "t_0=40*10**-6   #s\n",

-      "t_f=3*10**-6    #s\n",

-      "\n",

-      "#Calculations\n",

-      "P_st=I_CS*V_CES  # instant. power loss during t_s\n",

-      "P_s=f*I_CS*V_CES*t_f   #avg power loss during t_s\n",

-      "P_f=f*t_f*(I_CS/6)*(V_CC-V_CES)        #avg power loss during fall time\n",

-      "P_fm=(I_CS/4)*(V_CC-V_CES)          #peak instant power dissipation\n",

-      "P_off=P_s+P_f\n",

-      "\n",

-      "#Results\n",

-      "print(\"Total avg power loss during turn off = %.2f W\" %P_off)\n",

-      "P_0t=I_CEO*V_CC\n",

-      "print(\"Instantaneous power loss during t_0 = %.2f W\" %P_0t)\n",

-      "P_0=f*I_CEO*V_CC*t_0              #avg power loss during t_s\n",

-      "P_on=14.9339              #W    from previous eg\n",

-      "P_n=40                    #W    from previous eg\n",

-      "P_T=P_on+P_n+P_off+P_0     \n",

-      "print(\"Total power loss = %.2f W\" %P_T)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Total avg power loss during turn off = 44.91 W\n",

-        "Instantaneous power loss during t_0 = 0.44 W\n",

-        "Total power loss = 99.93 W\n"

-       ]

-      }

-     ],

-     "prompt_number": 8

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 2.4, Page No 28"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "I_CS=100.0 \n",

-      "V_CC=200.0 \n",

-      "t_on=40*10**-6\n",

-      "\n",

-      "#Calculations\n",

-      "P_on=(I_CS/50)*10**6*t_on*(V_CC*t_on/2-(V_CC*10**6*t_on**2/(40*3)))       #energy during turn on\n",

-      "t_off=60*10**-6\n",

-      "P_off=(I_CS*t_off/2-(I_CS/60)*10**6*(t_off**2)/3)*((V_CC/75)*10**6*t_off)  #energy during turn off\n",

-      "P_t=P_on+P_off           #total energy\n",

-      "P_avg=300.0\n",

-      "f=P_avg/P_t\n",

-      "\n",

-      "#Results\n",

-      "print(\"Allowable switching frequency = %.2f Hz\" %f)\n",

-      "#in book ans is: f=1123.6 Hz. The difference in results due to difference in rounding of of digits"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Allowable switching frequency = 1125.00 Hz\n"

-       ]

-      }

-     ],

-     "prompt_number": 10

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Power_Electronics/Chapter2_2.ipynb b/_Power_Electronics/Chapter2_2.ipynb
deleted file mode 100755
index 1872c9f4..00000000
--- a/_Power_Electronics/Chapter2_2.ipynb
+++ /dev/null
@@ -1,233 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 02 : Power Semiconductor Diodes and Transistors"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 2.1, Page No 21"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "B=40.0\n",

-      "R_c=10                    #ohm\n",

-      "V_cc=130.0                #V\n",

-      "V_B=10.0                  #V\n",

-      "V_CES=1.0                 #V\n",

-      "V_BES=1.5                 #V\n",

-      "\n",

-      "#Calculations\n",

-      "I_CS=(V_cc-V_CES)/R_c     #A\n",

-      "I_BS=I_CS/B                #A\n",

-      "R_B1=(V_B-V_BES)/I_BS\n",

-      "P_T1=V_BES*I_BS+V_CES*I_CS\n",

-      "ODF=5\n",

-      "I_B=ODF*I_BS\n",

-      "R_B2=(V_B-V_BES)/I_B\n",

-      "P_T2=V_BES*I_B+V_CES*I_CS\n",

-      "B_f=I_CS/I_B\n",

-      "\n",

-      "#Results\n",

-      "print(\"value of R_B in saturated state= %.2f ohm\" %R_B1)\n",

-      "print(\"Power loss in transistor=%.2f W\" %P_T1)\n",

-      "print(\"Value of R_B for an overdrive factor 5 = %.2f ohm\" %R_B2)\n",

-      "print(\"Power loss in transistor = %.2f W\" %P_T2)\n",

-      "print(\"Forced current gain=%.0f\" %B_f)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "value of R_B in saturated state= 26.36 ohm\n",

-        "Power loss in transistor=13.38 W\n",

-        "Value of R_B for an overdrive factor 5 = 5.27 ohm\n",

-        "Power loss in transistor = 15.32 W\n",

-        "Forced current gain=8\n"

-       ]

-      }

-     ],

-     "prompt_number": 5

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 2.2, Page No 24"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "I_CEO=2*10**-3            #A\n",

-      "V_CC=220.0                #V\n",

-      "P_dt=I_CEO*V_CC           #instant. power loss during delay time\n",

-      "t_d=.4*10**-6            #s\n",

-      "f=5000\n",

-      "P_d=f*I_CEO*V_CC*t_d      #avg power loss during delay time\n",

-      "V_CES=2                     #V\n",

-      "t_r=1*10**-6               #s\n",

-      "I_CS=80                    #A\n",

-      "\n",

-      "#Calculations\n",

-      "P_r=f*I_CS*t_r*(V_CC/2-(V_CC-V_CES)/3)            #avg power loss during rise time\n",

-      "t_m=V_CC*t_r/(2*(V_CC-V_CES))\n",

-      "P_rm=I_CS*V_CC**2/(4*(V_CC-V_CES))           #instant. power loss during rise time\n",

-      "\n",

-      "#Results\n",

-      "P_on=P_d+P_r                \n",

-      "print(\"Avg power loss during turn on = %.2f W\" %P_on)\n",

-      "P_nt=I_CS*V_CES \n",

-      "print(\"Instantaneous power loss during turn on = %.0f W\" %P_nt)\n",

-      "t_n=50*10**-6\n",

-      "P_n=f*I_CS*V_CES*t_n\n",

-      "print(\"Avg power loss during conduction period = %.0f W\" %P_n)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Avg power loss during turn on = 14.93 W\n",

-        "Instantaneous power loss during turn on = 160 W\n",

-        "Avg power loss during conduction period = 40 W\n"

-       ]

-      }

-     ],

-     "prompt_number": 7

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 2.3 Page No 26"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "I_CEO=2*10**-3         #A\n",

-      "V_CC=220          #V\n",

-      "t_d=.4*10**-6   #s\n",

-      "f=5000\n",

-      "V_CES=2         #V\n",

-      "t_r=1*10**-6    #s\n",

-      "I_CS=80         #A\n",

-      "t_n=50*10**-6   #s\n",

-      "t_0=40*10**-6   #s\n",

-      "t_f=3*10**-6    #s\n",

-      "\n",

-      "#Calculations\n",

-      "P_st=I_CS*V_CES  # instant. power loss during t_s\n",

-      "P_s=f*I_CS*V_CES*t_f   #avg power loss during t_s\n",

-      "P_f=f*t_f*(I_CS/6)*(V_CC-V_CES)        #avg power loss during fall time\n",

-      "P_fm=(I_CS/4)*(V_CC-V_CES)          #peak instant power dissipation\n",

-      "P_off=P_s+P_f\n",

-      "\n",

-      "#Results\n",

-      "print(\"Total avg power loss during turn off = %.2f W\" %P_off)\n",

-      "P_0t=I_CEO*V_CC\n",

-      "print(\"Instantaneous power loss during t_0 = %.2f W\" %P_0t)\n",

-      "P_0=f*I_CEO*V_CC*t_0              #avg power loss during t_s\n",

-      "P_on=14.9339              #W    from previous eg\n",

-      "P_n=40                    #W    from previous eg\n",

-      "P_T=P_on+P_n+P_off+P_0     \n",

-      "print(\"Total power loss = %.2f W\" %P_T)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Total avg power loss during turn off = 44.91 W\n",

-        "Instantaneous power loss during t_0 = 0.44 W\n",

-        "Total power loss = 99.93 W\n"

-       ]

-      }

-     ],

-     "prompt_number": 8

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 2.4, Page No 28"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "I_CS=100.0 \n",

-      "V_CC=200.0 \n",

-      "t_on=40*10**-6\n",

-      "\n",

-      "#Calculations\n",

-      "P_on=(I_CS/50)*10**6*t_on*(V_CC*t_on/2-(V_CC*10**6*t_on**2/(40*3)))       #energy during turn on\n",

-      "t_off=60*10**-6\n",

-      "P_off=(I_CS*t_off/2-(I_CS/60)*10**6*(t_off**2)/3)*((V_CC/75)*10**6*t_off)  #energy during turn off\n",

-      "P_t=P_on+P_off           #total energy\n",

-      "P_avg=300.0\n",

-      "f=P_avg/P_t\n",

-      "\n",

-      "#Results\n",

-      "print(\"Allowable switching frequency = %.2f Hz\" %f)\n",

-      "#in book ans is: f=1123.6 Hz. The difference in results due to difference in rounding of of digits"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Allowable switching frequency = 1125.00 Hz\n"

-       ]

-      }

-     ],

-     "prompt_number": 10

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Power_Electronics/Chapter2_3.ipynb b/_Power_Electronics/Chapter2_3.ipynb
deleted file mode 100755
index 1872c9f4..00000000
--- a/_Power_Electronics/Chapter2_3.ipynb
+++ /dev/null
@@ -1,233 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 02 : Power Semiconductor Diodes and Transistors"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 2.1, Page No 21"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "B=40.0\n",

-      "R_c=10                    #ohm\n",

-      "V_cc=130.0                #V\n",

-      "V_B=10.0                  #V\n",

-      "V_CES=1.0                 #V\n",

-      "V_BES=1.5                 #V\n",

-      "\n",

-      "#Calculations\n",

-      "I_CS=(V_cc-V_CES)/R_c     #A\n",

-      "I_BS=I_CS/B                #A\n",

-      "R_B1=(V_B-V_BES)/I_BS\n",

-      "P_T1=V_BES*I_BS+V_CES*I_CS\n",

-      "ODF=5\n",

-      "I_B=ODF*I_BS\n",

-      "R_B2=(V_B-V_BES)/I_B\n",

-      "P_T2=V_BES*I_B+V_CES*I_CS\n",

-      "B_f=I_CS/I_B\n",

-      "\n",

-      "#Results\n",

-      "print(\"value of R_B in saturated state= %.2f ohm\" %R_B1)\n",

-      "print(\"Power loss in transistor=%.2f W\" %P_T1)\n",

-      "print(\"Value of R_B for an overdrive factor 5 = %.2f ohm\" %R_B2)\n",

-      "print(\"Power loss in transistor = %.2f W\" %P_T2)\n",

-      "print(\"Forced current gain=%.0f\" %B_f)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "value of R_B in saturated state= 26.36 ohm\n",

-        "Power loss in transistor=13.38 W\n",

-        "Value of R_B for an overdrive factor 5 = 5.27 ohm\n",

-        "Power loss in transistor = 15.32 W\n",

-        "Forced current gain=8\n"

-       ]

-      }

-     ],

-     "prompt_number": 5

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 2.2, Page No 24"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "I_CEO=2*10**-3            #A\n",

-      "V_CC=220.0                #V\n",

-      "P_dt=I_CEO*V_CC           #instant. power loss during delay time\n",

-      "t_d=.4*10**-6            #s\n",

-      "f=5000\n",

-      "P_d=f*I_CEO*V_CC*t_d      #avg power loss during delay time\n",

-      "V_CES=2                     #V\n",

-      "t_r=1*10**-6               #s\n",

-      "I_CS=80                    #A\n",

-      "\n",

-      "#Calculations\n",

-      "P_r=f*I_CS*t_r*(V_CC/2-(V_CC-V_CES)/3)            #avg power loss during rise time\n",

-      "t_m=V_CC*t_r/(2*(V_CC-V_CES))\n",

-      "P_rm=I_CS*V_CC**2/(4*(V_CC-V_CES))           #instant. power loss during rise time\n",

-      "\n",

-      "#Results\n",

-      "P_on=P_d+P_r                \n",

-      "print(\"Avg power loss during turn on = %.2f W\" %P_on)\n",

-      "P_nt=I_CS*V_CES \n",

-      "print(\"Instantaneous power loss during turn on = %.0f W\" %P_nt)\n",

-      "t_n=50*10**-6\n",

-      "P_n=f*I_CS*V_CES*t_n\n",

-      "print(\"Avg power loss during conduction period = %.0f W\" %P_n)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Avg power loss during turn on = 14.93 W\n",

-        "Instantaneous power loss during turn on = 160 W\n",

-        "Avg power loss during conduction period = 40 W\n"

-       ]

-      }

-     ],

-     "prompt_number": 7

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 2.3 Page No 26"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "I_CEO=2*10**-3         #A\n",

-      "V_CC=220          #V\n",

-      "t_d=.4*10**-6   #s\n",

-      "f=5000\n",

-      "V_CES=2         #V\n",

-      "t_r=1*10**-6    #s\n",

-      "I_CS=80         #A\n",

-      "t_n=50*10**-6   #s\n",

-      "t_0=40*10**-6   #s\n",

-      "t_f=3*10**-6    #s\n",

-      "\n",

-      "#Calculations\n",

-      "P_st=I_CS*V_CES  # instant. power loss during t_s\n",

-      "P_s=f*I_CS*V_CES*t_f   #avg power loss during t_s\n",

-      "P_f=f*t_f*(I_CS/6)*(V_CC-V_CES)        #avg power loss during fall time\n",

-      "P_fm=(I_CS/4)*(V_CC-V_CES)          #peak instant power dissipation\n",

-      "P_off=P_s+P_f\n",

-      "\n",

-      "#Results\n",

-      "print(\"Total avg power loss during turn off = %.2f W\" %P_off)\n",

-      "P_0t=I_CEO*V_CC\n",

-      "print(\"Instantaneous power loss during t_0 = %.2f W\" %P_0t)\n",

-      "P_0=f*I_CEO*V_CC*t_0              #avg power loss during t_s\n",

-      "P_on=14.9339              #W    from previous eg\n",

-      "P_n=40                    #W    from previous eg\n",

-      "P_T=P_on+P_n+P_off+P_0     \n",

-      "print(\"Total power loss = %.2f W\" %P_T)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Total avg power loss during turn off = 44.91 W\n",

-        "Instantaneous power loss during t_0 = 0.44 W\n",

-        "Total power loss = 99.93 W\n"

-       ]

-      }

-     ],

-     "prompt_number": 8

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 2.4, Page No 28"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "I_CS=100.0 \n",

-      "V_CC=200.0 \n",

-      "t_on=40*10**-6\n",

-      "\n",

-      "#Calculations\n",

-      "P_on=(I_CS/50)*10**6*t_on*(V_CC*t_on/2-(V_CC*10**6*t_on**2/(40*3)))       #energy during turn on\n",

-      "t_off=60*10**-6\n",

-      "P_off=(I_CS*t_off/2-(I_CS/60)*10**6*(t_off**2)/3)*((V_CC/75)*10**6*t_off)  #energy during turn off\n",

-      "P_t=P_on+P_off           #total energy\n",

-      "P_avg=300.0\n",

-      "f=P_avg/P_t\n",

-      "\n",

-      "#Results\n",

-      "print(\"Allowable switching frequency = %.2f Hz\" %f)\n",

-      "#in book ans is: f=1123.6 Hz. The difference in results due to difference in rounding of of digits"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Allowable switching frequency = 1125.00 Hz\n"

-       ]

-      }

-     ],

-     "prompt_number": 10

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Power_Electronics/Chapter2_4.ipynb b/_Power_Electronics/Chapter2_4.ipynb
deleted file mode 100755
index 1872c9f4..00000000
--- a/_Power_Electronics/Chapter2_4.ipynb
+++ /dev/null
@@ -1,233 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 02 : Power Semiconductor Diodes and Transistors"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 2.1, Page No 21"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "B=40.0\n",

-      "R_c=10                    #ohm\n",

-      "V_cc=130.0                #V\n",

-      "V_B=10.0                  #V\n",

-      "V_CES=1.0                 #V\n",

-      "V_BES=1.5                 #V\n",

-      "\n",

-      "#Calculations\n",

-      "I_CS=(V_cc-V_CES)/R_c     #A\n",

-      "I_BS=I_CS/B                #A\n",

-      "R_B1=(V_B-V_BES)/I_BS\n",

-      "P_T1=V_BES*I_BS+V_CES*I_CS\n",

-      "ODF=5\n",

-      "I_B=ODF*I_BS\n",

-      "R_B2=(V_B-V_BES)/I_B\n",

-      "P_T2=V_BES*I_B+V_CES*I_CS\n",

-      "B_f=I_CS/I_B\n",

-      "\n",

-      "#Results\n",

-      "print(\"value of R_B in saturated state= %.2f ohm\" %R_B1)\n",

-      "print(\"Power loss in transistor=%.2f W\" %P_T1)\n",

-      "print(\"Value of R_B for an overdrive factor 5 = %.2f ohm\" %R_B2)\n",

-      "print(\"Power loss in transistor = %.2f W\" %P_T2)\n",

-      "print(\"Forced current gain=%.0f\" %B_f)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "value of R_B in saturated state= 26.36 ohm\n",

-        "Power loss in transistor=13.38 W\n",

-        "Value of R_B for an overdrive factor 5 = 5.27 ohm\n",

-        "Power loss in transistor = 15.32 W\n",

-        "Forced current gain=8\n"

-       ]

-      }

-     ],

-     "prompt_number": 5

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 2.2, Page No 24"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "I_CEO=2*10**-3            #A\n",

-      "V_CC=220.0                #V\n",

-      "P_dt=I_CEO*V_CC           #instant. power loss during delay time\n",

-      "t_d=.4*10**-6            #s\n",

-      "f=5000\n",

-      "P_d=f*I_CEO*V_CC*t_d      #avg power loss during delay time\n",

-      "V_CES=2                     #V\n",

-      "t_r=1*10**-6               #s\n",

-      "I_CS=80                    #A\n",

-      "\n",

-      "#Calculations\n",

-      "P_r=f*I_CS*t_r*(V_CC/2-(V_CC-V_CES)/3)            #avg power loss during rise time\n",

-      "t_m=V_CC*t_r/(2*(V_CC-V_CES))\n",

-      "P_rm=I_CS*V_CC**2/(4*(V_CC-V_CES))           #instant. power loss during rise time\n",

-      "\n",

-      "#Results\n",

-      "P_on=P_d+P_r                \n",

-      "print(\"Avg power loss during turn on = %.2f W\" %P_on)\n",

-      "P_nt=I_CS*V_CES \n",

-      "print(\"Instantaneous power loss during turn on = %.0f W\" %P_nt)\n",

-      "t_n=50*10**-6\n",

-      "P_n=f*I_CS*V_CES*t_n\n",

-      "print(\"Avg power loss during conduction period = %.0f W\" %P_n)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Avg power loss during turn on = 14.93 W\n",

-        "Instantaneous power loss during turn on = 160 W\n",

-        "Avg power loss during conduction period = 40 W\n"

-       ]

-      }

-     ],

-     "prompt_number": 7

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 2.3 Page No 26"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "I_CEO=2*10**-3         #A\n",

-      "V_CC=220          #V\n",

-      "t_d=.4*10**-6   #s\n",

-      "f=5000\n",

-      "V_CES=2         #V\n",

-      "t_r=1*10**-6    #s\n",

-      "I_CS=80         #A\n",

-      "t_n=50*10**-6   #s\n",

-      "t_0=40*10**-6   #s\n",

-      "t_f=3*10**-6    #s\n",

-      "\n",

-      "#Calculations\n",

-      "P_st=I_CS*V_CES  # instant. power loss during t_s\n",

-      "P_s=f*I_CS*V_CES*t_f   #avg power loss during t_s\n",

-      "P_f=f*t_f*(I_CS/6)*(V_CC-V_CES)        #avg power loss during fall time\n",

-      "P_fm=(I_CS/4)*(V_CC-V_CES)          #peak instant power dissipation\n",

-      "P_off=P_s+P_f\n",

-      "\n",

-      "#Results\n",

-      "print(\"Total avg power loss during turn off = %.2f W\" %P_off)\n",

-      "P_0t=I_CEO*V_CC\n",

-      "print(\"Instantaneous power loss during t_0 = %.2f W\" %P_0t)\n",

-      "P_0=f*I_CEO*V_CC*t_0              #avg power loss during t_s\n",

-      "P_on=14.9339              #W    from previous eg\n",

-      "P_n=40                    #W    from previous eg\n",

-      "P_T=P_on+P_n+P_off+P_0     \n",

-      "print(\"Total power loss = %.2f W\" %P_T)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Total avg power loss during turn off = 44.91 W\n",

-        "Instantaneous power loss during t_0 = 0.44 W\n",

-        "Total power loss = 99.93 W\n"

-       ]

-      }

-     ],

-     "prompt_number": 8

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 2.4, Page No 28"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "I_CS=100.0 \n",

-      "V_CC=200.0 \n",

-      "t_on=40*10**-6\n",

-      "\n",

-      "#Calculations\n",

-      "P_on=(I_CS/50)*10**6*t_on*(V_CC*t_on/2-(V_CC*10**6*t_on**2/(40*3)))       #energy during turn on\n",

-      "t_off=60*10**-6\n",

-      "P_off=(I_CS*t_off/2-(I_CS/60)*10**6*(t_off**2)/3)*((V_CC/75)*10**6*t_off)  #energy during turn off\n",

-      "P_t=P_on+P_off           #total energy\n",

-      "P_avg=300.0\n",

-      "f=P_avg/P_t\n",

-      "\n",

-      "#Results\n",

-      "print(\"Allowable switching frequency = %.2f Hz\" %f)\n",

-      "#in book ans is: f=1123.6 Hz. The difference in results due to difference in rounding of of digits"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Allowable switching frequency = 1125.00 Hz\n"

-       ]

-      }

-     ],

-     "prompt_number": 10

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Power_Electronics/Chapter3.ipynb b/_Power_Electronics/Chapter3.ipynb
deleted file mode 100755
index 2e53ef9d..00000000
--- a/_Power_Electronics/Chapter3.ipynb
+++ /dev/null
@@ -1,1001 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 03 : Diode Circuits and Rectifiers"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.2, Page No 55"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=400.0  #V\n",

-      "V_o=100.0    #V\n",

-      "L=100.0      #uH\n",

-      "C=30.0       #uF\n",

-      "\n",

-      "#Calculations\n",

-      "t_o=math.pi*math.sqrt(L*C)\n",

-      "print(\"conduction time of diode = %.2f us\" %t_o)\n",

-      "#in book solution is t_o=54.77 us. The ans is incorrect as %pi is not muliplied in ans. Formulae mentioned in correct.\n",

-      "I_p=(V_s-V_o)*math.sqrt(C/L)\n",

-      "\n",

-      "#Results\n",

-      "print(\"Peak current through diode=%.2f A\" %I_p)\n",

-      "v_D=-V_s+V_o \n",

-      "print(\"Voltage across diode = %.2f V\" %v_D)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "conduction time of diode = 172.07 us\n",

-        "Peak current through diode=164.32 A\n",

-        "Voltage across diode = -300.00 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 26

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.6, Page No 61"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "\n",

-      "R=10             #ohm\n",

-      "L=0.001           #H\n",

-      "C=5*10**-6       #F\n",

-      "V_s=230          #V\n",

-      "xi=R/(2*L)\n",

-      "\n",

-      "#Calculations\n",

-      "w_o=1/math.sqrt(L*C)\n",

-      "w_r=math.sqrt((1/(L*C))-(R/(2*L))**2)\n",

-      "t=math.pi/w_r \n",

-      "\n",

-      "#Results\n",

-      "print('Conduction time of diode=%.3f us'%(t*10**6))\n",

-      "t=0\n",

-      "di=V_s/L\n",

-      "print('Rate of change of current at t=0 is %.2f A/s' %di)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Conduction time of diode=237.482 us\n",

-        "Rate of change of current at t=0 is 230000.00 A/s\n"

-       ]

-      }

-     ],

-     "prompt_number": 27

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.7 Page No 69"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "I_or=100             #A\n",

-      "R=1.0       #assumption\n",

-      "\n",

-      "#Calculations\n",

-      "V_m=I_or*2*R\n",

-      "I_o=V_m/(math.pi*R)\n",

-      "q=200       #Ah\n",

-      "t=q/I_o\n",

-      "\n",

-      "#Results\n",

-      "print(\"time required to deliver charge=%.02f hrs\" %t)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "time required to deliver charge=3.14 hrs\n"

-       ]

-      }

-     ],

-     "prompt_number": 28

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.8, Page No 70"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0    #V\n",

-      "P=1000       #W\n",

-      "R=V_s**2/P\n",

-      "\n",

-      "#Calculations\n",

-      "V_or=math.sqrt(2)*V_s/2\n",

-      "P_h=V_or**2/R    \n",

-      "print(\"Power delivered to the heater = %.2f W\" %P_h)\n",

-      "V_m=math.sqrt(2)*230\n",

-      "I_m=V_m/R\n",

-      "\n",

-      "#Results\n",

-      "print(\"Peak value of diode current = %.2f A\" %I_m)\n",

-      "pf=V_or/V_s\n",

-      "print(\"Input power factor=%.2f\" %pf)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Power delivered to the heater = 500.00 W\n",

-        "Peak value of diode current = 6.15 A\n",

-        "Input power factor=0.71\n"

-       ]

-      }

-     ],

-     "prompt_number": 29

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.9 Page No 71"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230        #V\n",

-      "V_m=V_s*math.sqrt(2)\n",

-      "E=150          #V\n",

-      "\n",

-      "#Calculations\n",

-      "theta1=math.degrees(E/(math.sqrt(2)*V_s))\n",

-      "R=8        #ohm\n",

-      "f=50    #Hz\n",

-      "I_o=(1/(2*math.pi*R))*((2*math.sqrt(2)*V_s*math.cos(math.radians(theta1)))-E*(math.pi-2*theta1*math.pi/180))\n",

-      "\n",

-      "#Results\n",

-      "print(\"avg value of charging current=%.2f A\" %I_o)\n",

-      "P_d=E*I_o\n",

-      "print(\"\\npower delivered to battery=%.2f W\" %P_d)\n",

-      "I_or=math.sqrt((1/(2*math.pi*R**2))*((V_s**2+E**2)*(math.pi-2*theta1*math.pi/180)+V_s**2*math.sin(math.radians(2*theta1))-4*V_m*E*math.cos(math.radians(theta1))))\n",

-      "print(\"\\nrms value of the load current=%.2f A\" %I_or)\n",

-      "pf=(E*I_o+I_or**2*R)/(V_s*I_or)\n",

-      "print(\"\\nsupply pf=%.3f\" %pf)\n",

-      "P_dd=I_or**2*R\n",

-      "print(\"\\npower dissipated in the resistor=%.2f W\" %P_dd)\n",

-      "q=1000.00         #Wh\n",

-      "t=q/P_d    \n",

-      "print(\"\\ncharging time=%.2f hr\" %t)\n",

-      "n=P_d*100/(P_d+P_dd)\n",

-      "print(\"rectifier efficiency =%.2f  \" %n)\n",

-      "PIV=math.sqrt(2)*V_s+E\n",

-      "print(\"PIV of diode=%.2f V\" %PIV)\n",

-      "#solutions have small variations due to difference in rounding off of digits"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "avg value of charging current=4.97 A\n",

-        "\n",

-        "power delivered to battery=745.11 W\n",

-        "\n",

-        "rms value of the load current=9.29 A\n",

-        "\n",

-        "supply pf=0.672\n",

-        "\n",

-        "power dissipated in the resistor=690.74 W\n",

-        "\n",

-        "charging time=1.34 hr\n",

-        "rectifier efficiency =51.89  \n",

-        "PIV of diode=475.27 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 30

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.10 Page No 78"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "V_s=230            #V\n",

-      "t_rr=40*10**-6    #s reverde recovery time\n",

-      "\n",

-      "#Calculations\n",

-      "V_o=2*math.sqrt(2)*V_s/math.pi\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "f=50\n",

-      "V_r1=(V_m/math.pi)*(1-math.cos(math.radians(2*math.pi*f*t_rr*180/math.pi)))\n",

-      "v_avg1=V_r1*100/V_o*10**3\n",

-      "f=2500\n",

-      "V_r2=(V_m/math.pi)*(1-math.cos(math.radians(2*math.pi*f*t_rr*180/math.pi)))\n",

-      "v_avg2=V_r2*100/V_o\n",

-      "\n",

-      "#Results\n",

-      "print(\"when f=50Hz\")\n",

-      "print(\"Percentage reduction in avg o/p voltage=%.2f x 10^-3\" %v_avg1)\n",

-      "print(\"when f=2500Hz\")\n",

-      "print(\"Percentage reduction in avg o/p voltage = %.3f\" %v_avg2)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "when f=50Hz\n",

-        "Percentage reduction in avg o/p voltage=3.95 x 10^-3\n",

-        "when f=2500Hz\n",

-        "Percentage reduction in avg o/p voltage = 9.549\n"

-       ]

-      }

-     ],

-     "prompt_number": 31

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.11, Page No 79 "

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230         #V\n",

-      "R=10.0        #ohm\n",

-      "\n",

-      "#Calculations\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "V_o=2*V_m/math.pi\n",

-      "print(\"Avg value of o/p voltage = %.2f V\" %V_o)\n",

-      "I_o=V_o/R\n",

-      "print(\"Avg value of o/p current = %.2f A\" %I_o)\n",

-      "I_DA=I_o/2\n",

-      "print(\"Avg value of diode current=%.2f A\" %I_DA)\n",

-      "I_Dr=I_o/math.sqrt(2)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"rms value of diode current=%.2f A\" %I_Dr)\n",

-      "print(\"rms value of o/p current = %.2f A\" %I_o)\n",

-      "print(\"rms value of i/p current = %.2f A\" %I_o)\n",

-      "pf=(V_o/V_s)\n",

-      "print(\"supply pf = %.2f\" %pf)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Avg value of o/p voltage = 207.07 V\n",

-        "Avg value of o/p current = 20.71 A\n",

-        "Avg value of diode current=10.35 A\n",

-        "rms value of diode current=14.64 A\n",

-        "rms value of o/p current = 20.71 A\n",

-        "rms value of i/p current = 20.71 A\n",

-        "supply pf = 0.90\n"

-       ]

-      }

-     ],

-     "prompt_number": 32

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.12 Page No 80"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math \n",

-      "\n",

-      "#initialisation of variables\n",

-      "V_s=230.0    #V\n",

-      "R=1000.0      #ohm\n",

-      "R_D=20.0    #ohm\n",

-      "\n",

-      "#Calculations\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "I_om=V_m/(R+R_D)          \n",

-      "\n",

-      "#Results\n",

-      "print(\"Peak load current = %.2f A\" %I_om)\n",

-      "I_o=I_om/math.pi\n",

-      "print(\"dc load current = %.2f A\" %I_o)\n",

-      "V_D=I_o*R_D-V_m/math.pi\n",

-      "print(\"dc diode voltage = %.2f V\" %V_D)\n",

-      "V_on=V_m/math.pi\n",

-      "print(\"at no load, load voltage = %.2f V\" %V_on)\n",

-      "V_o1=I_o*R    \n",

-      "print(\"at given load, load voltage = %.2f V\" %V_o1)\n",

-      "vr=(V_on-V_o1)*100/V_on    \n",

-      "print(\"Voltage regulation(in percent)=%.2f\" %vr)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Peak load current = 0.32 A\n",

-        "dc load current = 0.10 A\n",

-        "dc diode voltage = -101.51 V\n",

-        "at no load, load voltage = 103.54 V\n",

-        "at given load, load voltage = 101.51 V\n",

-        "Voltage regulation(in percent)=1.96\n"

-       ]

-      }

-     ],

-     "prompt_number": 33

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.13 Page No 82"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_L=6.8   #V\n",

-      "V_smax=20*1.2    #V\n",

-      "V_smin=20*.8     #V\n",

-      "I_Lmax=30*1.5   #mA\n",

-      "I_Lmin=30*0.5  #mA\n",

-      "I_z=1          #mA\n",

-      "\n",

-      "#Calculations\n",

-      "R_smax=(V_smax-V_L)/((I_Lmin+I_z)*10**-3)\n",

-      "print(\"max source resistance = %.2f ohm\" %R_smax)\n",

-      "R_smin=(V_smin-V_L)/((I_Lmax+I_z)*10**-3)    \n",

-      "print(\"Min source resistance = %.2f ohm\" %R_smin)  #in book solution, error is committed in putting the values in formulea(printing error) but solution is correct\n",

-      "R_Lmax=V_L*1000/I_Lmin\n",

-      "print(\"Max load resistance = %.2f ohm\" %R_Lmax)\n",

-      "R_Lmin=V_L*1000/I_Lmax    \n",

-      "V_d=0.6      #V\n",

-      "V_r=V_L-V_d\n",

-      "\n",

-      "#Results\n",

-      "print(\"Min load resistance=%.2f ohm\" %R_Lmin)\n",

-      "print(\"Voltage rating of zener diode=%.2f V\" %V_r)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "max source resistance = 1075.00 ohm\n",

-        "Min source resistance = 200.00 ohm\n",

-        "Max load resistance = 453.33 ohm\n",

-        "Min load resistance=151.11 ohm\n",

-        "Voltage rating of zener diode=6.20 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 34

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.14 Page No 83"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "I2=200*10**-6      #A\n",

-      "V_z=20       #V\n",

-      "R_G=500.0   #hm\n",

-      "\n",

-      "#Calculations\n",

-      "R2=(V_z/I2)-R_G\n",

-      "print(\"R2=%.2f kilo-ohm\" %(R2/1000))\n",

-      "\n",

-      "V_v=25      #V\n",

-      "I1=I2\n",

-      "R1=(V_v-V_z)/I1\n",

-      "\n",

-      "#Results\n",

-      "print(\"R1=%.0f kilo-ohm\"%(R1/1000))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "R2=99.50 kilo-ohm\n",

-        "R1=25 kilo-ohm\n"

-       ]

-      }

-     ],

-     "prompt_number": 35

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.15, Page No 92"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "V_s=2*230          #V\n",

-      "\n",

-      "#Calculations\n",

-      "V_o=(math.sqrt(2)*V_s)/math.pi\n",

-      "R=60                #ohm\n",

-      "P_dc=(V_o)**2/R\n",

-      "TUF=0.2865\n",

-      "VA=P_dc/TUF\n",

-      "\n",

-      "#RESULTS\n",

-      "print(\"kVA rating of the transformer = %.2f kVA\" %(VA/1000));\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "kVA rating of the transformer = 2.49 kVA\n"

-       ]

-      }

-     ],

-     "prompt_number": 36

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.16, Page No 92"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "tr=0.5       #turns ratio\n",

-      "I_o=10.0\n",

-      "V=230.0\n",

-      "V_s=V/tr\n",

-      "\n",

-      "#Calculations\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "V_o=2*V_m/math.pi\n",

-      "phi1=0\n",

-      "#displacemnt angle=0 as fundamnetal component of i/p source current in phase with source voltage\n",

-      "DF=math.cos(math.radians(phi1))\n",

-      "I_s1=4*I_o/(math.sqrt(2)*math.pi)\n",

-      "I_s=math.sqrt(I_o**2*math.pi/math.pi)\n",

-      "CDF=I_s1/I_o\n",

-      "pf=CDF*DF\n",

-      "HF=math.sqrt((I_s/I_s1)**2-1)\n",

-      "CF=I_o/I_s\n",

-      "\n",

-      "#Results\n",

-      "print(\"o/p voltage = %.2f V\" %V_o)\n",

-      "print(\"distortion factor = %.2f\" %DF)\n",

-      "print(\"i/p pf=%.2f\" %pf)\n",

-      "print(\"Current displacent factor=%.2f\" %CDF)\n",

-      "print(\"Harmonic factor = %.2f\" %HF)\n",

-      "print(\"Creast factor = %.2f\" %CF)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "o/p voltage = 414.15 V\n",

-        "distortion factor = 1.00\n",

-        "i/p pf=0.90\n",

-        "Current displacent factor=0.90\n",

-        "Harmonic factor = 0.48\n",

-        "Creast factor = 1.00\n"

-       ]

-      }

-     ],

-     "prompt_number": 37

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.17, Page No 94"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_o=230.0\n",

-      "R=10.0\n",

-      "V_s=V_o*math.pi/(2*math.sqrt(2))\n",

-      "I_o=V_o/R\n",

-      "I_m=math.sqrt(2)*V_s/R\n",

-      "I_DAV=I_m/math.pi\n",

-      "\n",

-      "#Calculations\n",

-      "#avg value of diode current\n",

-      "I_Dr=I_m/2\n",

-      "PIV=math.sqrt(2)*V_s\n",

-      "I_s=I_m/math.sqrt(2)\n",

-      "TF=V_s*I_s\n",

-      "\n",

-      "#Results\n",

-      "print(\"peak diode current=%.2f A\" %I_m)\n",

-      "print(\"I_DAV=%.2f A\" %I_DAV)\n",

-      "print(\"I_Dr=%.2f A\" %I_Dr)   #rms value of diode current\n",

-      "print(\"PIV=%.1f V\" %PIV)\n",

-      "print(\"Transformer rating = %.2f kVA\" %(TF/1000))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "peak diode current=36.13 A\n",

-        "I_DAV=11.50 A\n",

-        "I_Dr=18.06 A\n",

-        "PIV=361.3 V\n",

-        "Transformer rating = 6.53 kVA\n"

-       ]

-      }

-     ],

-     "prompt_number": 38

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.18, Page No 103"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "tr=5\n",

-      "V=1100.0\n",

-      "R=10.0\n",

-      "\n",

-      "\n",

-      "#Calculations\n",

-      "print(\"In case of 3ph-3pulse type\")\n",

-      "V_ph=V/tr\n",

-      "V_mp=math.sqrt(2)*V_ph\n",

-      "V_o=3*math.sqrt(3)*V_mp/(2*math.pi)\n",

-      "print(\"avg o/p voltage=%.1f V\" %V_o)\n",

-      "I_mp=V_mp/R\n",

-      "I_D=(I_mp/math.pi)*math.sin(math.pi/3)    \n",

-      "print(\"\\navg value of diode current=%.3f A\" %I_D)\n",

-      "I_Dr=I_mp*math.sqrt((1/(2*math.pi))*(math.pi/3+.5*math.sin(2*math.pi/3)))    \n",

-      "print(\"\\nrms value of diode current=%.2f A\" %I_Dr)\n",

-      "V_or=V_mp*math.sqrt((3/(2*math.pi))*(math.pi/3+.5*math.sin(2*math.pi/3)))\n",

-      "P=(V_or**2)/R   \n",

-      "print(\"\\npower delivered=%.1f W\" %P)\n",

-      "print(\"in case of 3ph-M6 type\")\n",

-      "V_ph=V_ph/2\n",

-      "V_mp=math.sqrt(2)*V_ph\n",

-      "V_o=3*V_mp/(math.pi)  \n",

-      "I_mp=V_mp/R\n",

-      "I_D=(I_mp/math.pi)*math.sin(math.pi/6)    \n",

-      "I_Dr=I_mp*math.sqrt((1/(2*math.pi))*(math.pi/6+.5*math.sin(2*math.pi/6)))  \n",

-      "V_or=V_mp*math.sqrt((6/(2*math.pi))*(math.pi/6+.5*math.sin(2*math.pi/6)))\n",

-      "P=(V_or**2)/R   \n",

-      "\n",

-      "#Results\n",

-      "print(\"avg o/p voltage=%.2f V\" %V_o)\n",

-      "print(\"\\navg value of diode current=%.2f A\" %I_D)\n",

-      "print(\"\\nrms value of diode current=%.2f A\" %I_Dr)\n",

-      "print(\"\\npower delivered=%.0f W\" %P)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "In case of 3ph-3pulse type\n",

-        "avg o/p voltage=257.3 V\n",

-        "\n",

-        "avg value of diode current=8.577 A\n",

-        "\n",

-        "rms value of diode current=15.10 A\n",

-        "\n",

-        "power delivered=6841.3 W\n",

-        "in case of 3ph-M6 type\n",

-        "avg o/p voltage=148.55 V\n",

-        "\n",

-        "avg value of diode current=2.48 A\n",

-        "\n",

-        "rms value of diode current=6.07 A\n",

-        "\n",

-        "power delivered=2211 W\n"

-       ]

-      }

-     ],

-     "prompt_number": 39

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.19, Page No 115"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_o=400\n",

-      "R=10\n",

-      "\n",

-      "#Calculations\n",

-      "V_ml=V_o*math.pi/3\n",

-      "V_s=V_ml/(math.sqrt(2)*math.sqrt(3))\n",

-      "I_m=V_ml/R\n",

-      "I_s=.7804*I_m\n",

-      "tr=3*V_s*I_s   \n",

-      "\n",

-      "#Results\n",

-      "print(\"transformer rating=%.1f VA\" %tr)\n",

-      "I_Dr=.5518*I_m   \n",

-      "print(\"\\nrms value of diode current=%.3f A\" %I_Dr)\n",

-      "I_D=I_m/math.pi   \n",

-      "print(\"\\navg value of diode current=%.3f A\" %I_D)\n",

-      "print(\"\\npeak diode current=%.2f A\" %I_m)\n",

-      "PIV=V_ml \n",

-      "print(\"\\nPIV=%.2f V\" %PIV)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "transformer rating=16770.3 VA\n",

-        "\n",

-        "rms value of diode current=23.114 A\n",

-        "\n",

-        "avg value of diode current=13.333 A\n",

-        "\n",

-        "peak diode current=41.89 A\n",

-        "\n",

-        "PIV=418.88 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 40

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.20, Page No 116"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_l=230\n",

-      "E=240\n",

-      "R=8\n",

-      "\n",

-      "#Calculations\n",

-      "V_ml=math.sqrt(2)*V_l\n",

-      "V_o=3*V_ml/math.pi\n",

-      "I_o=(V_o-E)/R\n",

-      "P_b=E*I_o    \n",

-      "P_d=E*I_o+I_o**2*R   \n",

-      "phi1=0\n",

-      "math.cos(math.radians(phi1))\n",

-      "I_s1=2*math.sqrt(3)*I_o/(math.sqrt(2)*math.pi)\n",

-      "I_s=math.sqrt(I_o**2*2*math.pi/(3*math.pi))\n",

-      "CDF=I_s1/I_s    \n",

-      "pf=DF*CDF    \n",

-      "HF=math.sqrt(CDF**-2-1)   \n",

-      "tr=math.sqrt(3)*V_l*I_o*math.sqrt(2/3)\n",

-      "\n",

-      "#Results\n",

-      "print(\"Power delivered to battery=%.1f W\" %P_b)\n",

-      "print(\"Power delivered to load=%.2f W\" %P_d)\n",

-      "print(\"Displacement factor=%.2f\" %DF)\n",

-      "print(\"Current distortion factor=%.3f\" %CDF)\n",

-      "print(\"i/p pf=%.3f\"%pf)\n",

-      "print(\"Harmonic factor=%.2f\" %HF)\n",

-      "print(\"Tranformer rating=%.2f VA\" %tr)\n",

-      "#answers have small variations from the book due to difference in rounding off of digits"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Power delivered to battery=2118.3 W\n",

-        "Power delivered to load=2741.48 W\n",

-        "Displacement factor=1.00\n",

-        "Current distortion factor=0.955\n",

-        "i/p pf=0.955\n",

-        "Harmonic factor=0.31\n",

-        "Tranformer rating=0.00 VA\n"

-       ]

-      }

-     ],

-     "prompt_number": 41

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.21, Page No 122"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "f=50  #Hz\n",

-      "V=230.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_m=math.sqrt(2)*V\n",

-      "R=400.0\n",

-      "RF=0.05\n",

-      "C=(1/(4*f*R))*(1+(1/(math.sqrt(2)*RF)))\n",

-      "\n",

-      "#Results\n",

-      "print(\"capacitor value=%.2f uF\" %(C/10**-6))\n",

-      "V_o=V_m*(1-1/(4*f*R*C))\n",

-      "print(\"o/p voltage with filter=%.2f V\" %V_o)\n",

-      "V_o=2*V_m/math.pi   \n",

-      "print(\"o/p voltage without filter=%.2f V\" %V_o)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "capacitor value=189.28 uF\n",

-        "o/p voltage with filter=303.79 V\n",

-        "o/p voltage without filter=207.07 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 42

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.22, Page No 122"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "f=50\n",

-      "CRF=0.05\n",

-      "R=300\n",

-      "\n",

-      "#Calculations\n",

-      "L=math.sqrt((CRF/(.4715*R))**-2-R**2)/(2*2*math.pi*f)    \n",

-      "print(\"L=%.2f H\" %L)\n",

-      "R=30\n",

-      "L=math.sqrt((CRF/(.4715*R))**-2-R**2)/(2*2*math.pi*f)    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"\\nL=%.2f H\" %L)\n",

-      "L=0\n",

-      "CRF=.4715*R/math.sqrt(R**2+(2*2*math.pi*f*L)**2)   \n",

-      "print(\"\\nCRF=%.2f\" %CRF)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "L=4.48 H\n",

-        "\n",

-        "L=0.45 H\n",

-        "\n",

-        "CRF=0.47\n"

-       ]

-      }

-     ],

-     "prompt_number": 43

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.23, Page No 127"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "R=50\n",

-      "L_L=10*10**-3\n",

-      "f=50.0\n",

-      "w=2*math.pi*f\n",

-      "\n",

-      "#Calculations\n",

-      "C=10/(2*w*math.sqrt(R**2+(2*w*L_L)**2))\n",

-      "\n",

-      "#Results\n",

-      "print(\"C=%.2f uF\" %(C*10**6))\n",

-      "VRF=0.1\n",

-      "L=(1/(4*w**2*C))*((math.sqrt(2)/(3*VRF))+1)\n",

-      "print(\"\\nL=%.2f mH\" %(L*10**3))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "C=315.83 uF\n",

-        "\n",

-        "L=45.83 mH\n"

-       ]

-      }

-     ],

-     "prompt_number": 44

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Power_Electronics/Chapter3_1.ipynb b/_Power_Electronics/Chapter3_1.ipynb
deleted file mode 100755
index 2e53ef9d..00000000
--- a/_Power_Electronics/Chapter3_1.ipynb
+++ /dev/null
@@ -1,1001 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 03 : Diode Circuits and Rectifiers"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.2, Page No 55"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=400.0  #V\n",

-      "V_o=100.0    #V\n",

-      "L=100.0      #uH\n",

-      "C=30.0       #uF\n",

-      "\n",

-      "#Calculations\n",

-      "t_o=math.pi*math.sqrt(L*C)\n",

-      "print(\"conduction time of diode = %.2f us\" %t_o)\n",

-      "#in book solution is t_o=54.77 us. The ans is incorrect as %pi is not muliplied in ans. Formulae mentioned in correct.\n",

-      "I_p=(V_s-V_o)*math.sqrt(C/L)\n",

-      "\n",

-      "#Results\n",

-      "print(\"Peak current through diode=%.2f A\" %I_p)\n",

-      "v_D=-V_s+V_o \n",

-      "print(\"Voltage across diode = %.2f V\" %v_D)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "conduction time of diode = 172.07 us\n",

-        "Peak current through diode=164.32 A\n",

-        "Voltage across diode = -300.00 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 26

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.6, Page No 61"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "\n",

-      "R=10             #ohm\n",

-      "L=0.001           #H\n",

-      "C=5*10**-6       #F\n",

-      "V_s=230          #V\n",

-      "xi=R/(2*L)\n",

-      "\n",

-      "#Calculations\n",

-      "w_o=1/math.sqrt(L*C)\n",

-      "w_r=math.sqrt((1/(L*C))-(R/(2*L))**2)\n",

-      "t=math.pi/w_r \n",

-      "\n",

-      "#Results\n",

-      "print('Conduction time of diode=%.3f us'%(t*10**6))\n",

-      "t=0\n",

-      "di=V_s/L\n",

-      "print('Rate of change of current at t=0 is %.2f A/s' %di)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Conduction time of diode=237.482 us\n",

-        "Rate of change of current at t=0 is 230000.00 A/s\n"

-       ]

-      }

-     ],

-     "prompt_number": 27

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.7 Page No 69"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "I_or=100             #A\n",

-      "R=1.0       #assumption\n",

-      "\n",

-      "#Calculations\n",

-      "V_m=I_or*2*R\n",

-      "I_o=V_m/(math.pi*R)\n",

-      "q=200       #Ah\n",

-      "t=q/I_o\n",

-      "\n",

-      "#Results\n",

-      "print(\"time required to deliver charge=%.02f hrs\" %t)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "time required to deliver charge=3.14 hrs\n"

-       ]

-      }

-     ],

-     "prompt_number": 28

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.8, Page No 70"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0    #V\n",

-      "P=1000       #W\n",

-      "R=V_s**2/P\n",

-      "\n",

-      "#Calculations\n",

-      "V_or=math.sqrt(2)*V_s/2\n",

-      "P_h=V_or**2/R    \n",

-      "print(\"Power delivered to the heater = %.2f W\" %P_h)\n",

-      "V_m=math.sqrt(2)*230\n",

-      "I_m=V_m/R\n",

-      "\n",

-      "#Results\n",

-      "print(\"Peak value of diode current = %.2f A\" %I_m)\n",

-      "pf=V_or/V_s\n",

-      "print(\"Input power factor=%.2f\" %pf)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Power delivered to the heater = 500.00 W\n",

-        "Peak value of diode current = 6.15 A\n",

-        "Input power factor=0.71\n"

-       ]

-      }

-     ],

-     "prompt_number": 29

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.9 Page No 71"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230        #V\n",

-      "V_m=V_s*math.sqrt(2)\n",

-      "E=150          #V\n",

-      "\n",

-      "#Calculations\n",

-      "theta1=math.degrees(E/(math.sqrt(2)*V_s))\n",

-      "R=8        #ohm\n",

-      "f=50    #Hz\n",

-      "I_o=(1/(2*math.pi*R))*((2*math.sqrt(2)*V_s*math.cos(math.radians(theta1)))-E*(math.pi-2*theta1*math.pi/180))\n",

-      "\n",

-      "#Results\n",

-      "print(\"avg value of charging current=%.2f A\" %I_o)\n",

-      "P_d=E*I_o\n",

-      "print(\"\\npower delivered to battery=%.2f W\" %P_d)\n",

-      "I_or=math.sqrt((1/(2*math.pi*R**2))*((V_s**2+E**2)*(math.pi-2*theta1*math.pi/180)+V_s**2*math.sin(math.radians(2*theta1))-4*V_m*E*math.cos(math.radians(theta1))))\n",

-      "print(\"\\nrms value of the load current=%.2f A\" %I_or)\n",

-      "pf=(E*I_o+I_or**2*R)/(V_s*I_or)\n",

-      "print(\"\\nsupply pf=%.3f\" %pf)\n",

-      "P_dd=I_or**2*R\n",

-      "print(\"\\npower dissipated in the resistor=%.2f W\" %P_dd)\n",

-      "q=1000.00         #Wh\n",

-      "t=q/P_d    \n",

-      "print(\"\\ncharging time=%.2f hr\" %t)\n",

-      "n=P_d*100/(P_d+P_dd)\n",

-      "print(\"rectifier efficiency =%.2f  \" %n)\n",

-      "PIV=math.sqrt(2)*V_s+E\n",

-      "print(\"PIV of diode=%.2f V\" %PIV)\n",

-      "#solutions have small variations due to difference in rounding off of digits"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "avg value of charging current=4.97 A\n",

-        "\n",

-        "power delivered to battery=745.11 W\n",

-        "\n",

-        "rms value of the load current=9.29 A\n",

-        "\n",

-        "supply pf=0.672\n",

-        "\n",

-        "power dissipated in the resistor=690.74 W\n",

-        "\n",

-        "charging time=1.34 hr\n",

-        "rectifier efficiency =51.89  \n",

-        "PIV of diode=475.27 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 30

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.10 Page No 78"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "V_s=230            #V\n",

-      "t_rr=40*10**-6    #s reverde recovery time\n",

-      "\n",

-      "#Calculations\n",

-      "V_o=2*math.sqrt(2)*V_s/math.pi\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "f=50\n",

-      "V_r1=(V_m/math.pi)*(1-math.cos(math.radians(2*math.pi*f*t_rr*180/math.pi)))\n",

-      "v_avg1=V_r1*100/V_o*10**3\n",

-      "f=2500\n",

-      "V_r2=(V_m/math.pi)*(1-math.cos(math.radians(2*math.pi*f*t_rr*180/math.pi)))\n",

-      "v_avg2=V_r2*100/V_o\n",

-      "\n",

-      "#Results\n",

-      "print(\"when f=50Hz\")\n",

-      "print(\"Percentage reduction in avg o/p voltage=%.2f x 10^-3\" %v_avg1)\n",

-      "print(\"when f=2500Hz\")\n",

-      "print(\"Percentage reduction in avg o/p voltage = %.3f\" %v_avg2)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "when f=50Hz\n",

-        "Percentage reduction in avg o/p voltage=3.95 x 10^-3\n",

-        "when f=2500Hz\n",

-        "Percentage reduction in avg o/p voltage = 9.549\n"

-       ]

-      }

-     ],

-     "prompt_number": 31

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.11, Page No 79 "

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230         #V\n",

-      "R=10.0        #ohm\n",

-      "\n",

-      "#Calculations\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "V_o=2*V_m/math.pi\n",

-      "print(\"Avg value of o/p voltage = %.2f V\" %V_o)\n",

-      "I_o=V_o/R\n",

-      "print(\"Avg value of o/p current = %.2f A\" %I_o)\n",

-      "I_DA=I_o/2\n",

-      "print(\"Avg value of diode current=%.2f A\" %I_DA)\n",

-      "I_Dr=I_o/math.sqrt(2)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"rms value of diode current=%.2f A\" %I_Dr)\n",

-      "print(\"rms value of o/p current = %.2f A\" %I_o)\n",

-      "print(\"rms value of i/p current = %.2f A\" %I_o)\n",

-      "pf=(V_o/V_s)\n",

-      "print(\"supply pf = %.2f\" %pf)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Avg value of o/p voltage = 207.07 V\n",

-        "Avg value of o/p current = 20.71 A\n",

-        "Avg value of diode current=10.35 A\n",

-        "rms value of diode current=14.64 A\n",

-        "rms value of o/p current = 20.71 A\n",

-        "rms value of i/p current = 20.71 A\n",

-        "supply pf = 0.90\n"

-       ]

-      }

-     ],

-     "prompt_number": 32

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.12 Page No 80"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math \n",

-      "\n",

-      "#initialisation of variables\n",

-      "V_s=230.0    #V\n",

-      "R=1000.0      #ohm\n",

-      "R_D=20.0    #ohm\n",

-      "\n",

-      "#Calculations\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "I_om=V_m/(R+R_D)          \n",

-      "\n",

-      "#Results\n",

-      "print(\"Peak load current = %.2f A\" %I_om)\n",

-      "I_o=I_om/math.pi\n",

-      "print(\"dc load current = %.2f A\" %I_o)\n",

-      "V_D=I_o*R_D-V_m/math.pi\n",

-      "print(\"dc diode voltage = %.2f V\" %V_D)\n",

-      "V_on=V_m/math.pi\n",

-      "print(\"at no load, load voltage = %.2f V\" %V_on)\n",

-      "V_o1=I_o*R    \n",

-      "print(\"at given load, load voltage = %.2f V\" %V_o1)\n",

-      "vr=(V_on-V_o1)*100/V_on    \n",

-      "print(\"Voltage regulation(in percent)=%.2f\" %vr)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Peak load current = 0.32 A\n",

-        "dc load current = 0.10 A\n",

-        "dc diode voltage = -101.51 V\n",

-        "at no load, load voltage = 103.54 V\n",

-        "at given load, load voltage = 101.51 V\n",

-        "Voltage regulation(in percent)=1.96\n"

-       ]

-      }

-     ],

-     "prompt_number": 33

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.13 Page No 82"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_L=6.8   #V\n",

-      "V_smax=20*1.2    #V\n",

-      "V_smin=20*.8     #V\n",

-      "I_Lmax=30*1.5   #mA\n",

-      "I_Lmin=30*0.5  #mA\n",

-      "I_z=1          #mA\n",

-      "\n",

-      "#Calculations\n",

-      "R_smax=(V_smax-V_L)/((I_Lmin+I_z)*10**-3)\n",

-      "print(\"max source resistance = %.2f ohm\" %R_smax)\n",

-      "R_smin=(V_smin-V_L)/((I_Lmax+I_z)*10**-3)    \n",

-      "print(\"Min source resistance = %.2f ohm\" %R_smin)  #in book solution, error is committed in putting the values in formulea(printing error) but solution is correct\n",

-      "R_Lmax=V_L*1000/I_Lmin\n",

-      "print(\"Max load resistance = %.2f ohm\" %R_Lmax)\n",

-      "R_Lmin=V_L*1000/I_Lmax    \n",

-      "V_d=0.6      #V\n",

-      "V_r=V_L-V_d\n",

-      "\n",

-      "#Results\n",

-      "print(\"Min load resistance=%.2f ohm\" %R_Lmin)\n",

-      "print(\"Voltage rating of zener diode=%.2f V\" %V_r)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "max source resistance = 1075.00 ohm\n",

-        "Min source resistance = 200.00 ohm\n",

-        "Max load resistance = 453.33 ohm\n",

-        "Min load resistance=151.11 ohm\n",

-        "Voltage rating of zener diode=6.20 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 34

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.14 Page No 83"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "I2=200*10**-6      #A\n",

-      "V_z=20       #V\n",

-      "R_G=500.0   #hm\n",

-      "\n",

-      "#Calculations\n",

-      "R2=(V_z/I2)-R_G\n",

-      "print(\"R2=%.2f kilo-ohm\" %(R2/1000))\n",

-      "\n",

-      "V_v=25      #V\n",

-      "I1=I2\n",

-      "R1=(V_v-V_z)/I1\n",

-      "\n",

-      "#Results\n",

-      "print(\"R1=%.0f kilo-ohm\"%(R1/1000))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "R2=99.50 kilo-ohm\n",

-        "R1=25 kilo-ohm\n"

-       ]

-      }

-     ],

-     "prompt_number": 35

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.15, Page No 92"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "V_s=2*230          #V\n",

-      "\n",

-      "#Calculations\n",

-      "V_o=(math.sqrt(2)*V_s)/math.pi\n",

-      "R=60                #ohm\n",

-      "P_dc=(V_o)**2/R\n",

-      "TUF=0.2865\n",

-      "VA=P_dc/TUF\n",

-      "\n",

-      "#RESULTS\n",

-      "print(\"kVA rating of the transformer = %.2f kVA\" %(VA/1000));\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "kVA rating of the transformer = 2.49 kVA\n"

-       ]

-      }

-     ],

-     "prompt_number": 36

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.16, Page No 92"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "tr=0.5       #turns ratio\n",

-      "I_o=10.0\n",

-      "V=230.0\n",

-      "V_s=V/tr\n",

-      "\n",

-      "#Calculations\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "V_o=2*V_m/math.pi\n",

-      "phi1=0\n",

-      "#displacemnt angle=0 as fundamnetal component of i/p source current in phase with source voltage\n",

-      "DF=math.cos(math.radians(phi1))\n",

-      "I_s1=4*I_o/(math.sqrt(2)*math.pi)\n",

-      "I_s=math.sqrt(I_o**2*math.pi/math.pi)\n",

-      "CDF=I_s1/I_o\n",

-      "pf=CDF*DF\n",

-      "HF=math.sqrt((I_s/I_s1)**2-1)\n",

-      "CF=I_o/I_s\n",

-      "\n",

-      "#Results\n",

-      "print(\"o/p voltage = %.2f V\" %V_o)\n",

-      "print(\"distortion factor = %.2f\" %DF)\n",

-      "print(\"i/p pf=%.2f\" %pf)\n",

-      "print(\"Current displacent factor=%.2f\" %CDF)\n",

-      "print(\"Harmonic factor = %.2f\" %HF)\n",

-      "print(\"Creast factor = %.2f\" %CF)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "o/p voltage = 414.15 V\n",

-        "distortion factor = 1.00\n",

-        "i/p pf=0.90\n",

-        "Current displacent factor=0.90\n",

-        "Harmonic factor = 0.48\n",

-        "Creast factor = 1.00\n"

-       ]

-      }

-     ],

-     "prompt_number": 37

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.17, Page No 94"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_o=230.0\n",

-      "R=10.0\n",

-      "V_s=V_o*math.pi/(2*math.sqrt(2))\n",

-      "I_o=V_o/R\n",

-      "I_m=math.sqrt(2)*V_s/R\n",

-      "I_DAV=I_m/math.pi\n",

-      "\n",

-      "#Calculations\n",

-      "#avg value of diode current\n",

-      "I_Dr=I_m/2\n",

-      "PIV=math.sqrt(2)*V_s\n",

-      "I_s=I_m/math.sqrt(2)\n",

-      "TF=V_s*I_s\n",

-      "\n",

-      "#Results\n",

-      "print(\"peak diode current=%.2f A\" %I_m)\n",

-      "print(\"I_DAV=%.2f A\" %I_DAV)\n",

-      "print(\"I_Dr=%.2f A\" %I_Dr)   #rms value of diode current\n",

-      "print(\"PIV=%.1f V\" %PIV)\n",

-      "print(\"Transformer rating = %.2f kVA\" %(TF/1000))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "peak diode current=36.13 A\n",

-        "I_DAV=11.50 A\n",

-        "I_Dr=18.06 A\n",

-        "PIV=361.3 V\n",

-        "Transformer rating = 6.53 kVA\n"

-       ]

-      }

-     ],

-     "prompt_number": 38

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.18, Page No 103"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "tr=5\n",

-      "V=1100.0\n",

-      "R=10.0\n",

-      "\n",

-      "\n",

-      "#Calculations\n",

-      "print(\"In case of 3ph-3pulse type\")\n",

-      "V_ph=V/tr\n",

-      "V_mp=math.sqrt(2)*V_ph\n",

-      "V_o=3*math.sqrt(3)*V_mp/(2*math.pi)\n",

-      "print(\"avg o/p voltage=%.1f V\" %V_o)\n",

-      "I_mp=V_mp/R\n",

-      "I_D=(I_mp/math.pi)*math.sin(math.pi/3)    \n",

-      "print(\"\\navg value of diode current=%.3f A\" %I_D)\n",

-      "I_Dr=I_mp*math.sqrt((1/(2*math.pi))*(math.pi/3+.5*math.sin(2*math.pi/3)))    \n",

-      "print(\"\\nrms value of diode current=%.2f A\" %I_Dr)\n",

-      "V_or=V_mp*math.sqrt((3/(2*math.pi))*(math.pi/3+.5*math.sin(2*math.pi/3)))\n",

-      "P=(V_or**2)/R   \n",

-      "print(\"\\npower delivered=%.1f W\" %P)\n",

-      "print(\"in case of 3ph-M6 type\")\n",

-      "V_ph=V_ph/2\n",

-      "V_mp=math.sqrt(2)*V_ph\n",

-      "V_o=3*V_mp/(math.pi)  \n",

-      "I_mp=V_mp/R\n",

-      "I_D=(I_mp/math.pi)*math.sin(math.pi/6)    \n",

-      "I_Dr=I_mp*math.sqrt((1/(2*math.pi))*(math.pi/6+.5*math.sin(2*math.pi/6)))  \n",

-      "V_or=V_mp*math.sqrt((6/(2*math.pi))*(math.pi/6+.5*math.sin(2*math.pi/6)))\n",

-      "P=(V_or**2)/R   \n",

-      "\n",

-      "#Results\n",

-      "print(\"avg o/p voltage=%.2f V\" %V_o)\n",

-      "print(\"\\navg value of diode current=%.2f A\" %I_D)\n",

-      "print(\"\\nrms value of diode current=%.2f A\" %I_Dr)\n",

-      "print(\"\\npower delivered=%.0f W\" %P)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "In case of 3ph-3pulse type\n",

-        "avg o/p voltage=257.3 V\n",

-        "\n",

-        "avg value of diode current=8.577 A\n",

-        "\n",

-        "rms value of diode current=15.10 A\n",

-        "\n",

-        "power delivered=6841.3 W\n",

-        "in case of 3ph-M6 type\n",

-        "avg o/p voltage=148.55 V\n",

-        "\n",

-        "avg value of diode current=2.48 A\n",

-        "\n",

-        "rms value of diode current=6.07 A\n",

-        "\n",

-        "power delivered=2211 W\n"

-       ]

-      }

-     ],

-     "prompt_number": 39

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.19, Page No 115"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_o=400\n",

-      "R=10\n",

-      "\n",

-      "#Calculations\n",

-      "V_ml=V_o*math.pi/3\n",

-      "V_s=V_ml/(math.sqrt(2)*math.sqrt(3))\n",

-      "I_m=V_ml/R\n",

-      "I_s=.7804*I_m\n",

-      "tr=3*V_s*I_s   \n",

-      "\n",

-      "#Results\n",

-      "print(\"transformer rating=%.1f VA\" %tr)\n",

-      "I_Dr=.5518*I_m   \n",

-      "print(\"\\nrms value of diode current=%.3f A\" %I_Dr)\n",

-      "I_D=I_m/math.pi   \n",

-      "print(\"\\navg value of diode current=%.3f A\" %I_D)\n",

-      "print(\"\\npeak diode current=%.2f A\" %I_m)\n",

-      "PIV=V_ml \n",

-      "print(\"\\nPIV=%.2f V\" %PIV)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "transformer rating=16770.3 VA\n",

-        "\n",

-        "rms value of diode current=23.114 A\n",

-        "\n",

-        "avg value of diode current=13.333 A\n",

-        "\n",

-        "peak diode current=41.89 A\n",

-        "\n",

-        "PIV=418.88 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 40

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.20, Page No 116"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_l=230\n",

-      "E=240\n",

-      "R=8\n",

-      "\n",

-      "#Calculations\n",

-      "V_ml=math.sqrt(2)*V_l\n",

-      "V_o=3*V_ml/math.pi\n",

-      "I_o=(V_o-E)/R\n",

-      "P_b=E*I_o    \n",

-      "P_d=E*I_o+I_o**2*R   \n",

-      "phi1=0\n",

-      "math.cos(math.radians(phi1))\n",

-      "I_s1=2*math.sqrt(3)*I_o/(math.sqrt(2)*math.pi)\n",

-      "I_s=math.sqrt(I_o**2*2*math.pi/(3*math.pi))\n",

-      "CDF=I_s1/I_s    \n",

-      "pf=DF*CDF    \n",

-      "HF=math.sqrt(CDF**-2-1)   \n",

-      "tr=math.sqrt(3)*V_l*I_o*math.sqrt(2/3)\n",

-      "\n",

-      "#Results\n",

-      "print(\"Power delivered to battery=%.1f W\" %P_b)\n",

-      "print(\"Power delivered to load=%.2f W\" %P_d)\n",

-      "print(\"Displacement factor=%.2f\" %DF)\n",

-      "print(\"Current distortion factor=%.3f\" %CDF)\n",

-      "print(\"i/p pf=%.3f\"%pf)\n",

-      "print(\"Harmonic factor=%.2f\" %HF)\n",

-      "print(\"Tranformer rating=%.2f VA\" %tr)\n",

-      "#answers have small variations from the book due to difference in rounding off of digits"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Power delivered to battery=2118.3 W\n",

-        "Power delivered to load=2741.48 W\n",

-        "Displacement factor=1.00\n",

-        "Current distortion factor=0.955\n",

-        "i/p pf=0.955\n",

-        "Harmonic factor=0.31\n",

-        "Tranformer rating=0.00 VA\n"

-       ]

-      }

-     ],

-     "prompt_number": 41

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.21, Page No 122"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "f=50  #Hz\n",

-      "V=230.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_m=math.sqrt(2)*V\n",

-      "R=400.0\n",

-      "RF=0.05\n",

-      "C=(1/(4*f*R))*(1+(1/(math.sqrt(2)*RF)))\n",

-      "\n",

-      "#Results\n",

-      "print(\"capacitor value=%.2f uF\" %(C/10**-6))\n",

-      "V_o=V_m*(1-1/(4*f*R*C))\n",

-      "print(\"o/p voltage with filter=%.2f V\" %V_o)\n",

-      "V_o=2*V_m/math.pi   \n",

-      "print(\"o/p voltage without filter=%.2f V\" %V_o)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "capacitor value=189.28 uF\n",

-        "o/p voltage with filter=303.79 V\n",

-        "o/p voltage without filter=207.07 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 42

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.22, Page No 122"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "f=50\n",

-      "CRF=0.05\n",

-      "R=300\n",

-      "\n",

-      "#Calculations\n",

-      "L=math.sqrt((CRF/(.4715*R))**-2-R**2)/(2*2*math.pi*f)    \n",

-      "print(\"L=%.2f H\" %L)\n",

-      "R=30\n",

-      "L=math.sqrt((CRF/(.4715*R))**-2-R**2)/(2*2*math.pi*f)    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"\\nL=%.2f H\" %L)\n",

-      "L=0\n",

-      "CRF=.4715*R/math.sqrt(R**2+(2*2*math.pi*f*L)**2)   \n",

-      "print(\"\\nCRF=%.2f\" %CRF)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "L=4.48 H\n",

-        "\n",

-        "L=0.45 H\n",

-        "\n",

-        "CRF=0.47\n"

-       ]

-      }

-     ],

-     "prompt_number": 43

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.23, Page No 127"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "R=50\n",

-      "L_L=10*10**-3\n",

-      "f=50.0\n",

-      "w=2*math.pi*f\n",

-      "\n",

-      "#Calculations\n",

-      "C=10/(2*w*math.sqrt(R**2+(2*w*L_L)**2))\n",

-      "\n",

-      "#Results\n",

-      "print(\"C=%.2f uF\" %(C*10**6))\n",

-      "VRF=0.1\n",

-      "L=(1/(4*w**2*C))*((math.sqrt(2)/(3*VRF))+1)\n",

-      "print(\"\\nL=%.2f mH\" %(L*10**3))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "C=315.83 uF\n",

-        "\n",

-        "L=45.83 mH\n"

-       ]

-      }

-     ],

-     "prompt_number": 44

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Power_Electronics/Chapter3_2.ipynb b/_Power_Electronics/Chapter3_2.ipynb
deleted file mode 100755
index 2e53ef9d..00000000
--- a/_Power_Electronics/Chapter3_2.ipynb
+++ /dev/null
@@ -1,1001 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 03 : Diode Circuits and Rectifiers"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.2, Page No 55"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=400.0  #V\n",

-      "V_o=100.0    #V\n",

-      "L=100.0      #uH\n",

-      "C=30.0       #uF\n",

-      "\n",

-      "#Calculations\n",

-      "t_o=math.pi*math.sqrt(L*C)\n",

-      "print(\"conduction time of diode = %.2f us\" %t_o)\n",

-      "#in book solution is t_o=54.77 us. The ans is incorrect as %pi is not muliplied in ans. Formulae mentioned in correct.\n",

-      "I_p=(V_s-V_o)*math.sqrt(C/L)\n",

-      "\n",

-      "#Results\n",

-      "print(\"Peak current through diode=%.2f A\" %I_p)\n",

-      "v_D=-V_s+V_o \n",

-      "print(\"Voltage across diode = %.2f V\" %v_D)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "conduction time of diode = 172.07 us\n",

-        "Peak current through diode=164.32 A\n",

-        "Voltage across diode = -300.00 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 26

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.6, Page No 61"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "\n",

-      "R=10             #ohm\n",

-      "L=0.001           #H\n",

-      "C=5*10**-6       #F\n",

-      "V_s=230          #V\n",

-      "xi=R/(2*L)\n",

-      "\n",

-      "#Calculations\n",

-      "w_o=1/math.sqrt(L*C)\n",

-      "w_r=math.sqrt((1/(L*C))-(R/(2*L))**2)\n",

-      "t=math.pi/w_r \n",

-      "\n",

-      "#Results\n",

-      "print('Conduction time of diode=%.3f us'%(t*10**6))\n",

-      "t=0\n",

-      "di=V_s/L\n",

-      "print('Rate of change of current at t=0 is %.2f A/s' %di)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Conduction time of diode=237.482 us\n",

-        "Rate of change of current at t=0 is 230000.00 A/s\n"

-       ]

-      }

-     ],

-     "prompt_number": 27

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.7 Page No 69"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "I_or=100             #A\n",

-      "R=1.0       #assumption\n",

-      "\n",

-      "#Calculations\n",

-      "V_m=I_or*2*R\n",

-      "I_o=V_m/(math.pi*R)\n",

-      "q=200       #Ah\n",

-      "t=q/I_o\n",

-      "\n",

-      "#Results\n",

-      "print(\"time required to deliver charge=%.02f hrs\" %t)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "time required to deliver charge=3.14 hrs\n"

-       ]

-      }

-     ],

-     "prompt_number": 28

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.8, Page No 70"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0    #V\n",

-      "P=1000       #W\n",

-      "R=V_s**2/P\n",

-      "\n",

-      "#Calculations\n",

-      "V_or=math.sqrt(2)*V_s/2\n",

-      "P_h=V_or**2/R    \n",

-      "print(\"Power delivered to the heater = %.2f W\" %P_h)\n",

-      "V_m=math.sqrt(2)*230\n",

-      "I_m=V_m/R\n",

-      "\n",

-      "#Results\n",

-      "print(\"Peak value of diode current = %.2f A\" %I_m)\n",

-      "pf=V_or/V_s\n",

-      "print(\"Input power factor=%.2f\" %pf)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Power delivered to the heater = 500.00 W\n",

-        "Peak value of diode current = 6.15 A\n",

-        "Input power factor=0.71\n"

-       ]

-      }

-     ],

-     "prompt_number": 29

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.9 Page No 71"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230        #V\n",

-      "V_m=V_s*math.sqrt(2)\n",

-      "E=150          #V\n",

-      "\n",

-      "#Calculations\n",

-      "theta1=math.degrees(E/(math.sqrt(2)*V_s))\n",

-      "R=8        #ohm\n",

-      "f=50    #Hz\n",

-      "I_o=(1/(2*math.pi*R))*((2*math.sqrt(2)*V_s*math.cos(math.radians(theta1)))-E*(math.pi-2*theta1*math.pi/180))\n",

-      "\n",

-      "#Results\n",

-      "print(\"avg value of charging current=%.2f A\" %I_o)\n",

-      "P_d=E*I_o\n",

-      "print(\"\\npower delivered to battery=%.2f W\" %P_d)\n",

-      "I_or=math.sqrt((1/(2*math.pi*R**2))*((V_s**2+E**2)*(math.pi-2*theta1*math.pi/180)+V_s**2*math.sin(math.radians(2*theta1))-4*V_m*E*math.cos(math.radians(theta1))))\n",

-      "print(\"\\nrms value of the load current=%.2f A\" %I_or)\n",

-      "pf=(E*I_o+I_or**2*R)/(V_s*I_or)\n",

-      "print(\"\\nsupply pf=%.3f\" %pf)\n",

-      "P_dd=I_or**2*R\n",

-      "print(\"\\npower dissipated in the resistor=%.2f W\" %P_dd)\n",

-      "q=1000.00         #Wh\n",

-      "t=q/P_d    \n",

-      "print(\"\\ncharging time=%.2f hr\" %t)\n",

-      "n=P_d*100/(P_d+P_dd)\n",

-      "print(\"rectifier efficiency =%.2f  \" %n)\n",

-      "PIV=math.sqrt(2)*V_s+E\n",

-      "print(\"PIV of diode=%.2f V\" %PIV)\n",

-      "#solutions have small variations due to difference in rounding off of digits"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "avg value of charging current=4.97 A\n",

-        "\n",

-        "power delivered to battery=745.11 W\n",

-        "\n",

-        "rms value of the load current=9.29 A\n",

-        "\n",

-        "supply pf=0.672\n",

-        "\n",

-        "power dissipated in the resistor=690.74 W\n",

-        "\n",

-        "charging time=1.34 hr\n",

-        "rectifier efficiency =51.89  \n",

-        "PIV of diode=475.27 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 30

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.10 Page No 78"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "V_s=230            #V\n",

-      "t_rr=40*10**-6    #s reverde recovery time\n",

-      "\n",

-      "#Calculations\n",

-      "V_o=2*math.sqrt(2)*V_s/math.pi\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "f=50\n",

-      "V_r1=(V_m/math.pi)*(1-math.cos(math.radians(2*math.pi*f*t_rr*180/math.pi)))\n",

-      "v_avg1=V_r1*100/V_o*10**3\n",

-      "f=2500\n",

-      "V_r2=(V_m/math.pi)*(1-math.cos(math.radians(2*math.pi*f*t_rr*180/math.pi)))\n",

-      "v_avg2=V_r2*100/V_o\n",

-      "\n",

-      "#Results\n",

-      "print(\"when f=50Hz\")\n",

-      "print(\"Percentage reduction in avg o/p voltage=%.2f x 10^-3\" %v_avg1)\n",

-      "print(\"when f=2500Hz\")\n",

-      "print(\"Percentage reduction in avg o/p voltage = %.3f\" %v_avg2)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "when f=50Hz\n",

-        "Percentage reduction in avg o/p voltage=3.95 x 10^-3\n",

-        "when f=2500Hz\n",

-        "Percentage reduction in avg o/p voltage = 9.549\n"

-       ]

-      }

-     ],

-     "prompt_number": 31

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.11, Page No 79 "

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230         #V\n",

-      "R=10.0        #ohm\n",

-      "\n",

-      "#Calculations\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "V_o=2*V_m/math.pi\n",

-      "print(\"Avg value of o/p voltage = %.2f V\" %V_o)\n",

-      "I_o=V_o/R\n",

-      "print(\"Avg value of o/p current = %.2f A\" %I_o)\n",

-      "I_DA=I_o/2\n",

-      "print(\"Avg value of diode current=%.2f A\" %I_DA)\n",

-      "I_Dr=I_o/math.sqrt(2)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"rms value of diode current=%.2f A\" %I_Dr)\n",

-      "print(\"rms value of o/p current = %.2f A\" %I_o)\n",

-      "print(\"rms value of i/p current = %.2f A\" %I_o)\n",

-      "pf=(V_o/V_s)\n",

-      "print(\"supply pf = %.2f\" %pf)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Avg value of o/p voltage = 207.07 V\n",

-        "Avg value of o/p current = 20.71 A\n",

-        "Avg value of diode current=10.35 A\n",

-        "rms value of diode current=14.64 A\n",

-        "rms value of o/p current = 20.71 A\n",

-        "rms value of i/p current = 20.71 A\n",

-        "supply pf = 0.90\n"

-       ]

-      }

-     ],

-     "prompt_number": 32

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.12 Page No 80"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math \n",

-      "\n",

-      "#initialisation of variables\n",

-      "V_s=230.0    #V\n",

-      "R=1000.0      #ohm\n",

-      "R_D=20.0    #ohm\n",

-      "\n",

-      "#Calculations\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "I_om=V_m/(R+R_D)          \n",

-      "\n",

-      "#Results\n",

-      "print(\"Peak load current = %.2f A\" %I_om)\n",

-      "I_o=I_om/math.pi\n",

-      "print(\"dc load current = %.2f A\" %I_o)\n",

-      "V_D=I_o*R_D-V_m/math.pi\n",

-      "print(\"dc diode voltage = %.2f V\" %V_D)\n",

-      "V_on=V_m/math.pi\n",

-      "print(\"at no load, load voltage = %.2f V\" %V_on)\n",

-      "V_o1=I_o*R    \n",

-      "print(\"at given load, load voltage = %.2f V\" %V_o1)\n",

-      "vr=(V_on-V_o1)*100/V_on    \n",

-      "print(\"Voltage regulation(in percent)=%.2f\" %vr)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Peak load current = 0.32 A\n",

-        "dc load current = 0.10 A\n",

-        "dc diode voltage = -101.51 V\n",

-        "at no load, load voltage = 103.54 V\n",

-        "at given load, load voltage = 101.51 V\n",

-        "Voltage regulation(in percent)=1.96\n"

-       ]

-      }

-     ],

-     "prompt_number": 33

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.13 Page No 82"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_L=6.8   #V\n",

-      "V_smax=20*1.2    #V\n",

-      "V_smin=20*.8     #V\n",

-      "I_Lmax=30*1.5   #mA\n",

-      "I_Lmin=30*0.5  #mA\n",

-      "I_z=1          #mA\n",

-      "\n",

-      "#Calculations\n",

-      "R_smax=(V_smax-V_L)/((I_Lmin+I_z)*10**-3)\n",

-      "print(\"max source resistance = %.2f ohm\" %R_smax)\n",

-      "R_smin=(V_smin-V_L)/((I_Lmax+I_z)*10**-3)    \n",

-      "print(\"Min source resistance = %.2f ohm\" %R_smin)  #in book solution, error is committed in putting the values in formulea(printing error) but solution is correct\n",

-      "R_Lmax=V_L*1000/I_Lmin\n",

-      "print(\"Max load resistance = %.2f ohm\" %R_Lmax)\n",

-      "R_Lmin=V_L*1000/I_Lmax    \n",

-      "V_d=0.6      #V\n",

-      "V_r=V_L-V_d\n",

-      "\n",

-      "#Results\n",

-      "print(\"Min load resistance=%.2f ohm\" %R_Lmin)\n",

-      "print(\"Voltage rating of zener diode=%.2f V\" %V_r)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "max source resistance = 1075.00 ohm\n",

-        "Min source resistance = 200.00 ohm\n",

-        "Max load resistance = 453.33 ohm\n",

-        "Min load resistance=151.11 ohm\n",

-        "Voltage rating of zener diode=6.20 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 34

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.14 Page No 83"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "I2=200*10**-6      #A\n",

-      "V_z=20       #V\n",

-      "R_G=500.0   #hm\n",

-      "\n",

-      "#Calculations\n",

-      "R2=(V_z/I2)-R_G\n",

-      "print(\"R2=%.2f kilo-ohm\" %(R2/1000))\n",

-      "\n",

-      "V_v=25      #V\n",

-      "I1=I2\n",

-      "R1=(V_v-V_z)/I1\n",

-      "\n",

-      "#Results\n",

-      "print(\"R1=%.0f kilo-ohm\"%(R1/1000))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "R2=99.50 kilo-ohm\n",

-        "R1=25 kilo-ohm\n"

-       ]

-      }

-     ],

-     "prompt_number": 35

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.15, Page No 92"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "V_s=2*230          #V\n",

-      "\n",

-      "#Calculations\n",

-      "V_o=(math.sqrt(2)*V_s)/math.pi\n",

-      "R=60                #ohm\n",

-      "P_dc=(V_o)**2/R\n",

-      "TUF=0.2865\n",

-      "VA=P_dc/TUF\n",

-      "\n",

-      "#RESULTS\n",

-      "print(\"kVA rating of the transformer = %.2f kVA\" %(VA/1000));\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "kVA rating of the transformer = 2.49 kVA\n"

-       ]

-      }

-     ],

-     "prompt_number": 36

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.16, Page No 92"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "tr=0.5       #turns ratio\n",

-      "I_o=10.0\n",

-      "V=230.0\n",

-      "V_s=V/tr\n",

-      "\n",

-      "#Calculations\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "V_o=2*V_m/math.pi\n",

-      "phi1=0\n",

-      "#displacemnt angle=0 as fundamnetal component of i/p source current in phase with source voltage\n",

-      "DF=math.cos(math.radians(phi1))\n",

-      "I_s1=4*I_o/(math.sqrt(2)*math.pi)\n",

-      "I_s=math.sqrt(I_o**2*math.pi/math.pi)\n",

-      "CDF=I_s1/I_o\n",

-      "pf=CDF*DF\n",

-      "HF=math.sqrt((I_s/I_s1)**2-1)\n",

-      "CF=I_o/I_s\n",

-      "\n",

-      "#Results\n",

-      "print(\"o/p voltage = %.2f V\" %V_o)\n",

-      "print(\"distortion factor = %.2f\" %DF)\n",

-      "print(\"i/p pf=%.2f\" %pf)\n",

-      "print(\"Current displacent factor=%.2f\" %CDF)\n",

-      "print(\"Harmonic factor = %.2f\" %HF)\n",

-      "print(\"Creast factor = %.2f\" %CF)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "o/p voltage = 414.15 V\n",

-        "distortion factor = 1.00\n",

-        "i/p pf=0.90\n",

-        "Current displacent factor=0.90\n",

-        "Harmonic factor = 0.48\n",

-        "Creast factor = 1.00\n"

-       ]

-      }

-     ],

-     "prompt_number": 37

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.17, Page No 94"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_o=230.0\n",

-      "R=10.0\n",

-      "V_s=V_o*math.pi/(2*math.sqrt(2))\n",

-      "I_o=V_o/R\n",

-      "I_m=math.sqrt(2)*V_s/R\n",

-      "I_DAV=I_m/math.pi\n",

-      "\n",

-      "#Calculations\n",

-      "#avg value of diode current\n",

-      "I_Dr=I_m/2\n",

-      "PIV=math.sqrt(2)*V_s\n",

-      "I_s=I_m/math.sqrt(2)\n",

-      "TF=V_s*I_s\n",

-      "\n",

-      "#Results\n",

-      "print(\"peak diode current=%.2f A\" %I_m)\n",

-      "print(\"I_DAV=%.2f A\" %I_DAV)\n",

-      "print(\"I_Dr=%.2f A\" %I_Dr)   #rms value of diode current\n",

-      "print(\"PIV=%.1f V\" %PIV)\n",

-      "print(\"Transformer rating = %.2f kVA\" %(TF/1000))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "peak diode current=36.13 A\n",

-        "I_DAV=11.50 A\n",

-        "I_Dr=18.06 A\n",

-        "PIV=361.3 V\n",

-        "Transformer rating = 6.53 kVA\n"

-       ]

-      }

-     ],

-     "prompt_number": 38

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.18, Page No 103"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "tr=5\n",

-      "V=1100.0\n",

-      "R=10.0\n",

-      "\n",

-      "\n",

-      "#Calculations\n",

-      "print(\"In case of 3ph-3pulse type\")\n",

-      "V_ph=V/tr\n",

-      "V_mp=math.sqrt(2)*V_ph\n",

-      "V_o=3*math.sqrt(3)*V_mp/(2*math.pi)\n",

-      "print(\"avg o/p voltage=%.1f V\" %V_o)\n",

-      "I_mp=V_mp/R\n",

-      "I_D=(I_mp/math.pi)*math.sin(math.pi/3)    \n",

-      "print(\"\\navg value of diode current=%.3f A\" %I_D)\n",

-      "I_Dr=I_mp*math.sqrt((1/(2*math.pi))*(math.pi/3+.5*math.sin(2*math.pi/3)))    \n",

-      "print(\"\\nrms value of diode current=%.2f A\" %I_Dr)\n",

-      "V_or=V_mp*math.sqrt((3/(2*math.pi))*(math.pi/3+.5*math.sin(2*math.pi/3)))\n",

-      "P=(V_or**2)/R   \n",

-      "print(\"\\npower delivered=%.1f W\" %P)\n",

-      "print(\"in case of 3ph-M6 type\")\n",

-      "V_ph=V_ph/2\n",

-      "V_mp=math.sqrt(2)*V_ph\n",

-      "V_o=3*V_mp/(math.pi)  \n",

-      "I_mp=V_mp/R\n",

-      "I_D=(I_mp/math.pi)*math.sin(math.pi/6)    \n",

-      "I_Dr=I_mp*math.sqrt((1/(2*math.pi))*(math.pi/6+.5*math.sin(2*math.pi/6)))  \n",

-      "V_or=V_mp*math.sqrt((6/(2*math.pi))*(math.pi/6+.5*math.sin(2*math.pi/6)))\n",

-      "P=(V_or**2)/R   \n",

-      "\n",

-      "#Results\n",

-      "print(\"avg o/p voltage=%.2f V\" %V_o)\n",

-      "print(\"\\navg value of diode current=%.2f A\" %I_D)\n",

-      "print(\"\\nrms value of diode current=%.2f A\" %I_Dr)\n",

-      "print(\"\\npower delivered=%.0f W\" %P)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "In case of 3ph-3pulse type\n",

-        "avg o/p voltage=257.3 V\n",

-        "\n",

-        "avg value of diode current=8.577 A\n",

-        "\n",

-        "rms value of diode current=15.10 A\n",

-        "\n",

-        "power delivered=6841.3 W\n",

-        "in case of 3ph-M6 type\n",

-        "avg o/p voltage=148.55 V\n",

-        "\n",

-        "avg value of diode current=2.48 A\n",

-        "\n",

-        "rms value of diode current=6.07 A\n",

-        "\n",

-        "power delivered=2211 W\n"

-       ]

-      }

-     ],

-     "prompt_number": 39

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.19, Page No 115"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_o=400\n",

-      "R=10\n",

-      "\n",

-      "#Calculations\n",

-      "V_ml=V_o*math.pi/3\n",

-      "V_s=V_ml/(math.sqrt(2)*math.sqrt(3))\n",

-      "I_m=V_ml/R\n",

-      "I_s=.7804*I_m\n",

-      "tr=3*V_s*I_s   \n",

-      "\n",

-      "#Results\n",

-      "print(\"transformer rating=%.1f VA\" %tr)\n",

-      "I_Dr=.5518*I_m   \n",

-      "print(\"\\nrms value of diode current=%.3f A\" %I_Dr)\n",

-      "I_D=I_m/math.pi   \n",

-      "print(\"\\navg value of diode current=%.3f A\" %I_D)\n",

-      "print(\"\\npeak diode current=%.2f A\" %I_m)\n",

-      "PIV=V_ml \n",

-      "print(\"\\nPIV=%.2f V\" %PIV)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "transformer rating=16770.3 VA\n",

-        "\n",

-        "rms value of diode current=23.114 A\n",

-        "\n",

-        "avg value of diode current=13.333 A\n",

-        "\n",

-        "peak diode current=41.89 A\n",

-        "\n",

-        "PIV=418.88 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 40

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.20, Page No 116"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_l=230\n",

-      "E=240\n",

-      "R=8\n",

-      "\n",

-      "#Calculations\n",

-      "V_ml=math.sqrt(2)*V_l\n",

-      "V_o=3*V_ml/math.pi\n",

-      "I_o=(V_o-E)/R\n",

-      "P_b=E*I_o    \n",

-      "P_d=E*I_o+I_o**2*R   \n",

-      "phi1=0\n",

-      "math.cos(math.radians(phi1))\n",

-      "I_s1=2*math.sqrt(3)*I_o/(math.sqrt(2)*math.pi)\n",

-      "I_s=math.sqrt(I_o**2*2*math.pi/(3*math.pi))\n",

-      "CDF=I_s1/I_s    \n",

-      "pf=DF*CDF    \n",

-      "HF=math.sqrt(CDF**-2-1)   \n",

-      "tr=math.sqrt(3)*V_l*I_o*math.sqrt(2/3)\n",

-      "\n",

-      "#Results\n",

-      "print(\"Power delivered to battery=%.1f W\" %P_b)\n",

-      "print(\"Power delivered to load=%.2f W\" %P_d)\n",

-      "print(\"Displacement factor=%.2f\" %DF)\n",

-      "print(\"Current distortion factor=%.3f\" %CDF)\n",

-      "print(\"i/p pf=%.3f\"%pf)\n",

-      "print(\"Harmonic factor=%.2f\" %HF)\n",

-      "print(\"Tranformer rating=%.2f VA\" %tr)\n",

-      "#answers have small variations from the book due to difference in rounding off of digits"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Power delivered to battery=2118.3 W\n",

-        "Power delivered to load=2741.48 W\n",

-        "Displacement factor=1.00\n",

-        "Current distortion factor=0.955\n",

-        "i/p pf=0.955\n",

-        "Harmonic factor=0.31\n",

-        "Tranformer rating=0.00 VA\n"

-       ]

-      }

-     ],

-     "prompt_number": 41

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.21, Page No 122"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "f=50  #Hz\n",

-      "V=230.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_m=math.sqrt(2)*V\n",

-      "R=400.0\n",

-      "RF=0.05\n",

-      "C=(1/(4*f*R))*(1+(1/(math.sqrt(2)*RF)))\n",

-      "\n",

-      "#Results\n",

-      "print(\"capacitor value=%.2f uF\" %(C/10**-6))\n",

-      "V_o=V_m*(1-1/(4*f*R*C))\n",

-      "print(\"o/p voltage with filter=%.2f V\" %V_o)\n",

-      "V_o=2*V_m/math.pi   \n",

-      "print(\"o/p voltage without filter=%.2f V\" %V_o)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "capacitor value=189.28 uF\n",

-        "o/p voltage with filter=303.79 V\n",

-        "o/p voltage without filter=207.07 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 42

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.22, Page No 122"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "f=50\n",

-      "CRF=0.05\n",

-      "R=300\n",

-      "\n",

-      "#Calculations\n",

-      "L=math.sqrt((CRF/(.4715*R))**-2-R**2)/(2*2*math.pi*f)    \n",

-      "print(\"L=%.2f H\" %L)\n",

-      "R=30\n",

-      "L=math.sqrt((CRF/(.4715*R))**-2-R**2)/(2*2*math.pi*f)    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"\\nL=%.2f H\" %L)\n",

-      "L=0\n",

-      "CRF=.4715*R/math.sqrt(R**2+(2*2*math.pi*f*L)**2)   \n",

-      "print(\"\\nCRF=%.2f\" %CRF)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "L=4.48 H\n",

-        "\n",

-        "L=0.45 H\n",

-        "\n",

-        "CRF=0.47\n"

-       ]

-      }

-     ],

-     "prompt_number": 43

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.23, Page No 127"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "R=50\n",

-      "L_L=10*10**-3\n",

-      "f=50.0\n",

-      "w=2*math.pi*f\n",

-      "\n",

-      "#Calculations\n",

-      "C=10/(2*w*math.sqrt(R**2+(2*w*L_L)**2))\n",

-      "\n",

-      "#Results\n",

-      "print(\"C=%.2f uF\" %(C*10**6))\n",

-      "VRF=0.1\n",

-      "L=(1/(4*w**2*C))*((math.sqrt(2)/(3*VRF))+1)\n",

-      "print(\"\\nL=%.2f mH\" %(L*10**3))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "C=315.83 uF\n",

-        "\n",

-        "L=45.83 mH\n"

-       ]

-      }

-     ],

-     "prompt_number": 44

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Power_Electronics/Chapter3_3.ipynb b/_Power_Electronics/Chapter3_3.ipynb
deleted file mode 100755
index 2e53ef9d..00000000
--- a/_Power_Electronics/Chapter3_3.ipynb
+++ /dev/null
@@ -1,1001 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 03 : Diode Circuits and Rectifiers"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.2, Page No 55"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=400.0  #V\n",

-      "V_o=100.0    #V\n",

-      "L=100.0      #uH\n",

-      "C=30.0       #uF\n",

-      "\n",

-      "#Calculations\n",

-      "t_o=math.pi*math.sqrt(L*C)\n",

-      "print(\"conduction time of diode = %.2f us\" %t_o)\n",

-      "#in book solution is t_o=54.77 us. The ans is incorrect as %pi is not muliplied in ans. Formulae mentioned in correct.\n",

-      "I_p=(V_s-V_o)*math.sqrt(C/L)\n",

-      "\n",

-      "#Results\n",

-      "print(\"Peak current through diode=%.2f A\" %I_p)\n",

-      "v_D=-V_s+V_o \n",

-      "print(\"Voltage across diode = %.2f V\" %v_D)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "conduction time of diode = 172.07 us\n",

-        "Peak current through diode=164.32 A\n",

-        "Voltage across diode = -300.00 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 26

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.6, Page No 61"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "\n",

-      "R=10             #ohm\n",

-      "L=0.001           #H\n",

-      "C=5*10**-6       #F\n",

-      "V_s=230          #V\n",

-      "xi=R/(2*L)\n",

-      "\n",

-      "#Calculations\n",

-      "w_o=1/math.sqrt(L*C)\n",

-      "w_r=math.sqrt((1/(L*C))-(R/(2*L))**2)\n",

-      "t=math.pi/w_r \n",

-      "\n",

-      "#Results\n",

-      "print('Conduction time of diode=%.3f us'%(t*10**6))\n",

-      "t=0\n",

-      "di=V_s/L\n",

-      "print('Rate of change of current at t=0 is %.2f A/s' %di)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Conduction time of diode=237.482 us\n",

-        "Rate of change of current at t=0 is 230000.00 A/s\n"

-       ]

-      }

-     ],

-     "prompt_number": 27

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.7 Page No 69"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "I_or=100             #A\n",

-      "R=1.0       #assumption\n",

-      "\n",

-      "#Calculations\n",

-      "V_m=I_or*2*R\n",

-      "I_o=V_m/(math.pi*R)\n",

-      "q=200       #Ah\n",

-      "t=q/I_o\n",

-      "\n",

-      "#Results\n",

-      "print(\"time required to deliver charge=%.02f hrs\" %t)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "time required to deliver charge=3.14 hrs\n"

-       ]

-      }

-     ],

-     "prompt_number": 28

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.8, Page No 70"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0    #V\n",

-      "P=1000       #W\n",

-      "R=V_s**2/P\n",

-      "\n",

-      "#Calculations\n",

-      "V_or=math.sqrt(2)*V_s/2\n",

-      "P_h=V_or**2/R    \n",

-      "print(\"Power delivered to the heater = %.2f W\" %P_h)\n",

-      "V_m=math.sqrt(2)*230\n",

-      "I_m=V_m/R\n",

-      "\n",

-      "#Results\n",

-      "print(\"Peak value of diode current = %.2f A\" %I_m)\n",

-      "pf=V_or/V_s\n",

-      "print(\"Input power factor=%.2f\" %pf)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Power delivered to the heater = 500.00 W\n",

-        "Peak value of diode current = 6.15 A\n",

-        "Input power factor=0.71\n"

-       ]

-      }

-     ],

-     "prompt_number": 29

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.9 Page No 71"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230        #V\n",

-      "V_m=V_s*math.sqrt(2)\n",

-      "E=150          #V\n",

-      "\n",

-      "#Calculations\n",

-      "theta1=math.degrees(E/(math.sqrt(2)*V_s))\n",

-      "R=8        #ohm\n",

-      "f=50    #Hz\n",

-      "I_o=(1/(2*math.pi*R))*((2*math.sqrt(2)*V_s*math.cos(math.radians(theta1)))-E*(math.pi-2*theta1*math.pi/180))\n",

-      "\n",

-      "#Results\n",

-      "print(\"avg value of charging current=%.2f A\" %I_o)\n",

-      "P_d=E*I_o\n",

-      "print(\"\\npower delivered to battery=%.2f W\" %P_d)\n",

-      "I_or=math.sqrt((1/(2*math.pi*R**2))*((V_s**2+E**2)*(math.pi-2*theta1*math.pi/180)+V_s**2*math.sin(math.radians(2*theta1))-4*V_m*E*math.cos(math.radians(theta1))))\n",

-      "print(\"\\nrms value of the load current=%.2f A\" %I_or)\n",

-      "pf=(E*I_o+I_or**2*R)/(V_s*I_or)\n",

-      "print(\"\\nsupply pf=%.3f\" %pf)\n",

-      "P_dd=I_or**2*R\n",

-      "print(\"\\npower dissipated in the resistor=%.2f W\" %P_dd)\n",

-      "q=1000.00         #Wh\n",

-      "t=q/P_d    \n",

-      "print(\"\\ncharging time=%.2f hr\" %t)\n",

-      "n=P_d*100/(P_d+P_dd)\n",

-      "print(\"rectifier efficiency =%.2f  \" %n)\n",

-      "PIV=math.sqrt(2)*V_s+E\n",

-      "print(\"PIV of diode=%.2f V\" %PIV)\n",

-      "#solutions have small variations due to difference in rounding off of digits"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "avg value of charging current=4.97 A\n",

-        "\n",

-        "power delivered to battery=745.11 W\n",

-        "\n",

-        "rms value of the load current=9.29 A\n",

-        "\n",

-        "supply pf=0.672\n",

-        "\n",

-        "power dissipated in the resistor=690.74 W\n",

-        "\n",

-        "charging time=1.34 hr\n",

-        "rectifier efficiency =51.89  \n",

-        "PIV of diode=475.27 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 30

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.10 Page No 78"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "V_s=230            #V\n",

-      "t_rr=40*10**-6    #s reverde recovery time\n",

-      "\n",

-      "#Calculations\n",

-      "V_o=2*math.sqrt(2)*V_s/math.pi\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "f=50\n",

-      "V_r1=(V_m/math.pi)*(1-math.cos(math.radians(2*math.pi*f*t_rr*180/math.pi)))\n",

-      "v_avg1=V_r1*100/V_o*10**3\n",

-      "f=2500\n",

-      "V_r2=(V_m/math.pi)*(1-math.cos(math.radians(2*math.pi*f*t_rr*180/math.pi)))\n",

-      "v_avg2=V_r2*100/V_o\n",

-      "\n",

-      "#Results\n",

-      "print(\"when f=50Hz\")\n",

-      "print(\"Percentage reduction in avg o/p voltage=%.2f x 10^-3\" %v_avg1)\n",

-      "print(\"when f=2500Hz\")\n",

-      "print(\"Percentage reduction in avg o/p voltage = %.3f\" %v_avg2)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "when f=50Hz\n",

-        "Percentage reduction in avg o/p voltage=3.95 x 10^-3\n",

-        "when f=2500Hz\n",

-        "Percentage reduction in avg o/p voltage = 9.549\n"

-       ]

-      }

-     ],

-     "prompt_number": 31

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.11, Page No 79 "

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230         #V\n",

-      "R=10.0        #ohm\n",

-      "\n",

-      "#Calculations\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "V_o=2*V_m/math.pi\n",

-      "print(\"Avg value of o/p voltage = %.2f V\" %V_o)\n",

-      "I_o=V_o/R\n",

-      "print(\"Avg value of o/p current = %.2f A\" %I_o)\n",

-      "I_DA=I_o/2\n",

-      "print(\"Avg value of diode current=%.2f A\" %I_DA)\n",

-      "I_Dr=I_o/math.sqrt(2)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"rms value of diode current=%.2f A\" %I_Dr)\n",

-      "print(\"rms value of o/p current = %.2f A\" %I_o)\n",

-      "print(\"rms value of i/p current = %.2f A\" %I_o)\n",

-      "pf=(V_o/V_s)\n",

-      "print(\"supply pf = %.2f\" %pf)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Avg value of o/p voltage = 207.07 V\n",

-        "Avg value of o/p current = 20.71 A\n",

-        "Avg value of diode current=10.35 A\n",

-        "rms value of diode current=14.64 A\n",

-        "rms value of o/p current = 20.71 A\n",

-        "rms value of i/p current = 20.71 A\n",

-        "supply pf = 0.90\n"

-       ]

-      }

-     ],

-     "prompt_number": 32

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.12 Page No 80"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math \n",

-      "\n",

-      "#initialisation of variables\n",

-      "V_s=230.0    #V\n",

-      "R=1000.0      #ohm\n",

-      "R_D=20.0    #ohm\n",

-      "\n",

-      "#Calculations\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "I_om=V_m/(R+R_D)          \n",

-      "\n",

-      "#Results\n",

-      "print(\"Peak load current = %.2f A\" %I_om)\n",

-      "I_o=I_om/math.pi\n",

-      "print(\"dc load current = %.2f A\" %I_o)\n",

-      "V_D=I_o*R_D-V_m/math.pi\n",

-      "print(\"dc diode voltage = %.2f V\" %V_D)\n",

-      "V_on=V_m/math.pi\n",

-      "print(\"at no load, load voltage = %.2f V\" %V_on)\n",

-      "V_o1=I_o*R    \n",

-      "print(\"at given load, load voltage = %.2f V\" %V_o1)\n",

-      "vr=(V_on-V_o1)*100/V_on    \n",

-      "print(\"Voltage regulation(in percent)=%.2f\" %vr)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Peak load current = 0.32 A\n",

-        "dc load current = 0.10 A\n",

-        "dc diode voltage = -101.51 V\n",

-        "at no load, load voltage = 103.54 V\n",

-        "at given load, load voltage = 101.51 V\n",

-        "Voltage regulation(in percent)=1.96\n"

-       ]

-      }

-     ],

-     "prompt_number": 33

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.13 Page No 82"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_L=6.8   #V\n",

-      "V_smax=20*1.2    #V\n",

-      "V_smin=20*.8     #V\n",

-      "I_Lmax=30*1.5   #mA\n",

-      "I_Lmin=30*0.5  #mA\n",

-      "I_z=1          #mA\n",

-      "\n",

-      "#Calculations\n",

-      "R_smax=(V_smax-V_L)/((I_Lmin+I_z)*10**-3)\n",

-      "print(\"max source resistance = %.2f ohm\" %R_smax)\n",

-      "R_smin=(V_smin-V_L)/((I_Lmax+I_z)*10**-3)    \n",

-      "print(\"Min source resistance = %.2f ohm\" %R_smin)  #in book solution, error is committed in putting the values in formulea(printing error) but solution is correct\n",

-      "R_Lmax=V_L*1000/I_Lmin\n",

-      "print(\"Max load resistance = %.2f ohm\" %R_Lmax)\n",

-      "R_Lmin=V_L*1000/I_Lmax    \n",

-      "V_d=0.6      #V\n",

-      "V_r=V_L-V_d\n",

-      "\n",

-      "#Results\n",

-      "print(\"Min load resistance=%.2f ohm\" %R_Lmin)\n",

-      "print(\"Voltage rating of zener diode=%.2f V\" %V_r)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "max source resistance = 1075.00 ohm\n",

-        "Min source resistance = 200.00 ohm\n",

-        "Max load resistance = 453.33 ohm\n",

-        "Min load resistance=151.11 ohm\n",

-        "Voltage rating of zener diode=6.20 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 34

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.14 Page No 83"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "I2=200*10**-6      #A\n",

-      "V_z=20       #V\n",

-      "R_G=500.0   #hm\n",

-      "\n",

-      "#Calculations\n",

-      "R2=(V_z/I2)-R_G\n",

-      "print(\"R2=%.2f kilo-ohm\" %(R2/1000))\n",

-      "\n",

-      "V_v=25      #V\n",

-      "I1=I2\n",

-      "R1=(V_v-V_z)/I1\n",

-      "\n",

-      "#Results\n",

-      "print(\"R1=%.0f kilo-ohm\"%(R1/1000))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "R2=99.50 kilo-ohm\n",

-        "R1=25 kilo-ohm\n"

-       ]

-      }

-     ],

-     "prompt_number": 35

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.15, Page No 92"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "V_s=2*230          #V\n",

-      "\n",

-      "#Calculations\n",

-      "V_o=(math.sqrt(2)*V_s)/math.pi\n",

-      "R=60                #ohm\n",

-      "P_dc=(V_o)**2/R\n",

-      "TUF=0.2865\n",

-      "VA=P_dc/TUF\n",

-      "\n",

-      "#RESULTS\n",

-      "print(\"kVA rating of the transformer = %.2f kVA\" %(VA/1000));\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "kVA rating of the transformer = 2.49 kVA\n"

-       ]

-      }

-     ],

-     "prompt_number": 36

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.16, Page No 92"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "tr=0.5       #turns ratio\n",

-      "I_o=10.0\n",

-      "V=230.0\n",

-      "V_s=V/tr\n",

-      "\n",

-      "#Calculations\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "V_o=2*V_m/math.pi\n",

-      "phi1=0\n",

-      "#displacemnt angle=0 as fundamnetal component of i/p source current in phase with source voltage\n",

-      "DF=math.cos(math.radians(phi1))\n",

-      "I_s1=4*I_o/(math.sqrt(2)*math.pi)\n",

-      "I_s=math.sqrt(I_o**2*math.pi/math.pi)\n",

-      "CDF=I_s1/I_o\n",

-      "pf=CDF*DF\n",

-      "HF=math.sqrt((I_s/I_s1)**2-1)\n",

-      "CF=I_o/I_s\n",

-      "\n",

-      "#Results\n",

-      "print(\"o/p voltage = %.2f V\" %V_o)\n",

-      "print(\"distortion factor = %.2f\" %DF)\n",

-      "print(\"i/p pf=%.2f\" %pf)\n",

-      "print(\"Current displacent factor=%.2f\" %CDF)\n",

-      "print(\"Harmonic factor = %.2f\" %HF)\n",

-      "print(\"Creast factor = %.2f\" %CF)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "o/p voltage = 414.15 V\n",

-        "distortion factor = 1.00\n",

-        "i/p pf=0.90\n",

-        "Current displacent factor=0.90\n",

-        "Harmonic factor = 0.48\n",

-        "Creast factor = 1.00\n"

-       ]

-      }

-     ],

-     "prompt_number": 37

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.17, Page No 94"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_o=230.0\n",

-      "R=10.0\n",

-      "V_s=V_o*math.pi/(2*math.sqrt(2))\n",

-      "I_o=V_o/R\n",

-      "I_m=math.sqrt(2)*V_s/R\n",

-      "I_DAV=I_m/math.pi\n",

-      "\n",

-      "#Calculations\n",

-      "#avg value of diode current\n",

-      "I_Dr=I_m/2\n",

-      "PIV=math.sqrt(2)*V_s\n",

-      "I_s=I_m/math.sqrt(2)\n",

-      "TF=V_s*I_s\n",

-      "\n",

-      "#Results\n",

-      "print(\"peak diode current=%.2f A\" %I_m)\n",

-      "print(\"I_DAV=%.2f A\" %I_DAV)\n",

-      "print(\"I_Dr=%.2f A\" %I_Dr)   #rms value of diode current\n",

-      "print(\"PIV=%.1f V\" %PIV)\n",

-      "print(\"Transformer rating = %.2f kVA\" %(TF/1000))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "peak diode current=36.13 A\n",

-        "I_DAV=11.50 A\n",

-        "I_Dr=18.06 A\n",

-        "PIV=361.3 V\n",

-        "Transformer rating = 6.53 kVA\n"

-       ]

-      }

-     ],

-     "prompt_number": 38

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.18, Page No 103"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "tr=5\n",

-      "V=1100.0\n",

-      "R=10.0\n",

-      "\n",

-      "\n",

-      "#Calculations\n",

-      "print(\"In case of 3ph-3pulse type\")\n",

-      "V_ph=V/tr\n",

-      "V_mp=math.sqrt(2)*V_ph\n",

-      "V_o=3*math.sqrt(3)*V_mp/(2*math.pi)\n",

-      "print(\"avg o/p voltage=%.1f V\" %V_o)\n",

-      "I_mp=V_mp/R\n",

-      "I_D=(I_mp/math.pi)*math.sin(math.pi/3)    \n",

-      "print(\"\\navg value of diode current=%.3f A\" %I_D)\n",

-      "I_Dr=I_mp*math.sqrt((1/(2*math.pi))*(math.pi/3+.5*math.sin(2*math.pi/3)))    \n",

-      "print(\"\\nrms value of diode current=%.2f A\" %I_Dr)\n",

-      "V_or=V_mp*math.sqrt((3/(2*math.pi))*(math.pi/3+.5*math.sin(2*math.pi/3)))\n",

-      "P=(V_or**2)/R   \n",

-      "print(\"\\npower delivered=%.1f W\" %P)\n",

-      "print(\"in case of 3ph-M6 type\")\n",

-      "V_ph=V_ph/2\n",

-      "V_mp=math.sqrt(2)*V_ph\n",

-      "V_o=3*V_mp/(math.pi)  \n",

-      "I_mp=V_mp/R\n",

-      "I_D=(I_mp/math.pi)*math.sin(math.pi/6)    \n",

-      "I_Dr=I_mp*math.sqrt((1/(2*math.pi))*(math.pi/6+.5*math.sin(2*math.pi/6)))  \n",

-      "V_or=V_mp*math.sqrt((6/(2*math.pi))*(math.pi/6+.5*math.sin(2*math.pi/6)))\n",

-      "P=(V_or**2)/R   \n",

-      "\n",

-      "#Results\n",

-      "print(\"avg o/p voltage=%.2f V\" %V_o)\n",

-      "print(\"\\navg value of diode current=%.2f A\" %I_D)\n",

-      "print(\"\\nrms value of diode current=%.2f A\" %I_Dr)\n",

-      "print(\"\\npower delivered=%.0f W\" %P)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "In case of 3ph-3pulse type\n",

-        "avg o/p voltage=257.3 V\n",

-        "\n",

-        "avg value of diode current=8.577 A\n",

-        "\n",

-        "rms value of diode current=15.10 A\n",

-        "\n",

-        "power delivered=6841.3 W\n",

-        "in case of 3ph-M6 type\n",

-        "avg o/p voltage=148.55 V\n",

-        "\n",

-        "avg value of diode current=2.48 A\n",

-        "\n",

-        "rms value of diode current=6.07 A\n",

-        "\n",

-        "power delivered=2211 W\n"

-       ]

-      }

-     ],

-     "prompt_number": 39

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.19, Page No 115"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_o=400\n",

-      "R=10\n",

-      "\n",

-      "#Calculations\n",

-      "V_ml=V_o*math.pi/3\n",

-      "V_s=V_ml/(math.sqrt(2)*math.sqrt(3))\n",

-      "I_m=V_ml/R\n",

-      "I_s=.7804*I_m\n",

-      "tr=3*V_s*I_s   \n",

-      "\n",

-      "#Results\n",

-      "print(\"transformer rating=%.1f VA\" %tr)\n",

-      "I_Dr=.5518*I_m   \n",

-      "print(\"\\nrms value of diode current=%.3f A\" %I_Dr)\n",

-      "I_D=I_m/math.pi   \n",

-      "print(\"\\navg value of diode current=%.3f A\" %I_D)\n",

-      "print(\"\\npeak diode current=%.2f A\" %I_m)\n",

-      "PIV=V_ml \n",

-      "print(\"\\nPIV=%.2f V\" %PIV)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "transformer rating=16770.3 VA\n",

-        "\n",

-        "rms value of diode current=23.114 A\n",

-        "\n",

-        "avg value of diode current=13.333 A\n",

-        "\n",

-        "peak diode current=41.89 A\n",

-        "\n",

-        "PIV=418.88 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 40

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.20, Page No 116"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_l=230\n",

-      "E=240\n",

-      "R=8\n",

-      "\n",

-      "#Calculations\n",

-      "V_ml=math.sqrt(2)*V_l\n",

-      "V_o=3*V_ml/math.pi\n",

-      "I_o=(V_o-E)/R\n",

-      "P_b=E*I_o    \n",

-      "P_d=E*I_o+I_o**2*R   \n",

-      "phi1=0\n",

-      "math.cos(math.radians(phi1))\n",

-      "I_s1=2*math.sqrt(3)*I_o/(math.sqrt(2)*math.pi)\n",

-      "I_s=math.sqrt(I_o**2*2*math.pi/(3*math.pi))\n",

-      "CDF=I_s1/I_s    \n",

-      "pf=DF*CDF    \n",

-      "HF=math.sqrt(CDF**-2-1)   \n",

-      "tr=math.sqrt(3)*V_l*I_o*math.sqrt(2/3)\n",

-      "\n",

-      "#Results\n",

-      "print(\"Power delivered to battery=%.1f W\" %P_b)\n",

-      "print(\"Power delivered to load=%.2f W\" %P_d)\n",

-      "print(\"Displacement factor=%.2f\" %DF)\n",

-      "print(\"Current distortion factor=%.3f\" %CDF)\n",

-      "print(\"i/p pf=%.3f\"%pf)\n",

-      "print(\"Harmonic factor=%.2f\" %HF)\n",

-      "print(\"Tranformer rating=%.2f VA\" %tr)\n",

-      "#answers have small variations from the book due to difference in rounding off of digits"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Power delivered to battery=2118.3 W\n",

-        "Power delivered to load=2741.48 W\n",

-        "Displacement factor=1.00\n",

-        "Current distortion factor=0.955\n",

-        "i/p pf=0.955\n",

-        "Harmonic factor=0.31\n",

-        "Tranformer rating=0.00 VA\n"

-       ]

-      }

-     ],

-     "prompt_number": 41

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.21, Page No 122"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "f=50  #Hz\n",

-      "V=230.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_m=math.sqrt(2)*V\n",

-      "R=400.0\n",

-      "RF=0.05\n",

-      "C=(1/(4*f*R))*(1+(1/(math.sqrt(2)*RF)))\n",

-      "\n",

-      "#Results\n",

-      "print(\"capacitor value=%.2f uF\" %(C/10**-6))\n",

-      "V_o=V_m*(1-1/(4*f*R*C))\n",

-      "print(\"o/p voltage with filter=%.2f V\" %V_o)\n",

-      "V_o=2*V_m/math.pi   \n",

-      "print(\"o/p voltage without filter=%.2f V\" %V_o)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "capacitor value=189.28 uF\n",

-        "o/p voltage with filter=303.79 V\n",

-        "o/p voltage without filter=207.07 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 42

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.22, Page No 122"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "f=50\n",

-      "CRF=0.05\n",

-      "R=300\n",

-      "\n",

-      "#Calculations\n",

-      "L=math.sqrt((CRF/(.4715*R))**-2-R**2)/(2*2*math.pi*f)    \n",

-      "print(\"L=%.2f H\" %L)\n",

-      "R=30\n",

-      "L=math.sqrt((CRF/(.4715*R))**-2-R**2)/(2*2*math.pi*f)    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"\\nL=%.2f H\" %L)\n",

-      "L=0\n",

-      "CRF=.4715*R/math.sqrt(R**2+(2*2*math.pi*f*L)**2)   \n",

-      "print(\"\\nCRF=%.2f\" %CRF)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "L=4.48 H\n",

-        "\n",

-        "L=0.45 H\n",

-        "\n",

-        "CRF=0.47\n"

-       ]

-      }

-     ],

-     "prompt_number": 43

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.23, Page No 127"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "R=50\n",

-      "L_L=10*10**-3\n",

-      "f=50.0\n",

-      "w=2*math.pi*f\n",

-      "\n",

-      "#Calculations\n",

-      "C=10/(2*w*math.sqrt(R**2+(2*w*L_L)**2))\n",

-      "\n",

-      "#Results\n",

-      "print(\"C=%.2f uF\" %(C*10**6))\n",

-      "VRF=0.1\n",

-      "L=(1/(4*w**2*C))*((math.sqrt(2)/(3*VRF))+1)\n",

-      "print(\"\\nL=%.2f mH\" %(L*10**3))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "C=315.83 uF\n",

-        "\n",

-        "L=45.83 mH\n"

-       ]

-      }

-     ],

-     "prompt_number": 44

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Power_Electronics/Chapter3_4.ipynb b/_Power_Electronics/Chapter3_4.ipynb
deleted file mode 100755
index 2e53ef9d..00000000
--- a/_Power_Electronics/Chapter3_4.ipynb
+++ /dev/null
@@ -1,1001 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 03 : Diode Circuits and Rectifiers"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.2, Page No 55"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=400.0  #V\n",

-      "V_o=100.0    #V\n",

-      "L=100.0      #uH\n",

-      "C=30.0       #uF\n",

-      "\n",

-      "#Calculations\n",

-      "t_o=math.pi*math.sqrt(L*C)\n",

-      "print(\"conduction time of diode = %.2f us\" %t_o)\n",

-      "#in book solution is t_o=54.77 us. The ans is incorrect as %pi is not muliplied in ans. Formulae mentioned in correct.\n",

-      "I_p=(V_s-V_o)*math.sqrt(C/L)\n",

-      "\n",

-      "#Results\n",

-      "print(\"Peak current through diode=%.2f A\" %I_p)\n",

-      "v_D=-V_s+V_o \n",

-      "print(\"Voltage across diode = %.2f V\" %v_D)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "conduction time of diode = 172.07 us\n",

-        "Peak current through diode=164.32 A\n",

-        "Voltage across diode = -300.00 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 26

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.6, Page No 61"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "\n",

-      "R=10             #ohm\n",

-      "L=0.001           #H\n",

-      "C=5*10**-6       #F\n",

-      "V_s=230          #V\n",

-      "xi=R/(2*L)\n",

-      "\n",

-      "#Calculations\n",

-      "w_o=1/math.sqrt(L*C)\n",

-      "w_r=math.sqrt((1/(L*C))-(R/(2*L))**2)\n",

-      "t=math.pi/w_r \n",

-      "\n",

-      "#Results\n",

-      "print('Conduction time of diode=%.3f us'%(t*10**6))\n",

-      "t=0\n",

-      "di=V_s/L\n",

-      "print('Rate of change of current at t=0 is %.2f A/s' %di)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Conduction time of diode=237.482 us\n",

-        "Rate of change of current at t=0 is 230000.00 A/s\n"

-       ]

-      }

-     ],

-     "prompt_number": 27

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.7 Page No 69"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "I_or=100             #A\n",

-      "R=1.0       #assumption\n",

-      "\n",

-      "#Calculations\n",

-      "V_m=I_or*2*R\n",

-      "I_o=V_m/(math.pi*R)\n",

-      "q=200       #Ah\n",

-      "t=q/I_o\n",

-      "\n",

-      "#Results\n",

-      "print(\"time required to deliver charge=%.02f hrs\" %t)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "time required to deliver charge=3.14 hrs\n"

-       ]

-      }

-     ],

-     "prompt_number": 28

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.8, Page No 70"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0    #V\n",

-      "P=1000       #W\n",

-      "R=V_s**2/P\n",

-      "\n",

-      "#Calculations\n",

-      "V_or=math.sqrt(2)*V_s/2\n",

-      "P_h=V_or**2/R    \n",

-      "print(\"Power delivered to the heater = %.2f W\" %P_h)\n",

-      "V_m=math.sqrt(2)*230\n",

-      "I_m=V_m/R\n",

-      "\n",

-      "#Results\n",

-      "print(\"Peak value of diode current = %.2f A\" %I_m)\n",

-      "pf=V_or/V_s\n",

-      "print(\"Input power factor=%.2f\" %pf)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Power delivered to the heater = 500.00 W\n",

-        "Peak value of diode current = 6.15 A\n",

-        "Input power factor=0.71\n"

-       ]

-      }

-     ],

-     "prompt_number": 29

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.9 Page No 71"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230        #V\n",

-      "V_m=V_s*math.sqrt(2)\n",

-      "E=150          #V\n",

-      "\n",

-      "#Calculations\n",

-      "theta1=math.degrees(E/(math.sqrt(2)*V_s))\n",

-      "R=8        #ohm\n",

-      "f=50    #Hz\n",

-      "I_o=(1/(2*math.pi*R))*((2*math.sqrt(2)*V_s*math.cos(math.radians(theta1)))-E*(math.pi-2*theta1*math.pi/180))\n",

-      "\n",

-      "#Results\n",

-      "print(\"avg value of charging current=%.2f A\" %I_o)\n",

-      "P_d=E*I_o\n",

-      "print(\"\\npower delivered to battery=%.2f W\" %P_d)\n",

-      "I_or=math.sqrt((1/(2*math.pi*R**2))*((V_s**2+E**2)*(math.pi-2*theta1*math.pi/180)+V_s**2*math.sin(math.radians(2*theta1))-4*V_m*E*math.cos(math.radians(theta1))))\n",

-      "print(\"\\nrms value of the load current=%.2f A\" %I_or)\n",

-      "pf=(E*I_o+I_or**2*R)/(V_s*I_or)\n",

-      "print(\"\\nsupply pf=%.3f\" %pf)\n",

-      "P_dd=I_or**2*R\n",

-      "print(\"\\npower dissipated in the resistor=%.2f W\" %P_dd)\n",

-      "q=1000.00         #Wh\n",

-      "t=q/P_d    \n",

-      "print(\"\\ncharging time=%.2f hr\" %t)\n",

-      "n=P_d*100/(P_d+P_dd)\n",

-      "print(\"rectifier efficiency =%.2f  \" %n)\n",

-      "PIV=math.sqrt(2)*V_s+E\n",

-      "print(\"PIV of diode=%.2f V\" %PIV)\n",

-      "#solutions have small variations due to difference in rounding off of digits"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "avg value of charging current=4.97 A\n",

-        "\n",

-        "power delivered to battery=745.11 W\n",

-        "\n",

-        "rms value of the load current=9.29 A\n",

-        "\n",

-        "supply pf=0.672\n",

-        "\n",

-        "power dissipated in the resistor=690.74 W\n",

-        "\n",

-        "charging time=1.34 hr\n",

-        "rectifier efficiency =51.89  \n",

-        "PIV of diode=475.27 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 30

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.10 Page No 78"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "V_s=230            #V\n",

-      "t_rr=40*10**-6    #s reverde recovery time\n",

-      "\n",

-      "#Calculations\n",

-      "V_o=2*math.sqrt(2)*V_s/math.pi\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "f=50\n",

-      "V_r1=(V_m/math.pi)*(1-math.cos(math.radians(2*math.pi*f*t_rr*180/math.pi)))\n",

-      "v_avg1=V_r1*100/V_o*10**3\n",

-      "f=2500\n",

-      "V_r2=(V_m/math.pi)*(1-math.cos(math.radians(2*math.pi*f*t_rr*180/math.pi)))\n",

-      "v_avg2=V_r2*100/V_o\n",

-      "\n",

-      "#Results\n",

-      "print(\"when f=50Hz\")\n",

-      "print(\"Percentage reduction in avg o/p voltage=%.2f x 10^-3\" %v_avg1)\n",

-      "print(\"when f=2500Hz\")\n",

-      "print(\"Percentage reduction in avg o/p voltage = %.3f\" %v_avg2)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "when f=50Hz\n",

-        "Percentage reduction in avg o/p voltage=3.95 x 10^-3\n",

-        "when f=2500Hz\n",

-        "Percentage reduction in avg o/p voltage = 9.549\n"

-       ]

-      }

-     ],

-     "prompt_number": 31

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.11, Page No 79 "

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230         #V\n",

-      "R=10.0        #ohm\n",

-      "\n",

-      "#Calculations\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "V_o=2*V_m/math.pi\n",

-      "print(\"Avg value of o/p voltage = %.2f V\" %V_o)\n",

-      "I_o=V_o/R\n",

-      "print(\"Avg value of o/p current = %.2f A\" %I_o)\n",

-      "I_DA=I_o/2\n",

-      "print(\"Avg value of diode current=%.2f A\" %I_DA)\n",

-      "I_Dr=I_o/math.sqrt(2)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"rms value of diode current=%.2f A\" %I_Dr)\n",

-      "print(\"rms value of o/p current = %.2f A\" %I_o)\n",

-      "print(\"rms value of i/p current = %.2f A\" %I_o)\n",

-      "pf=(V_o/V_s)\n",

-      "print(\"supply pf = %.2f\" %pf)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Avg value of o/p voltage = 207.07 V\n",

-        "Avg value of o/p current = 20.71 A\n",

-        "Avg value of diode current=10.35 A\n",

-        "rms value of diode current=14.64 A\n",

-        "rms value of o/p current = 20.71 A\n",

-        "rms value of i/p current = 20.71 A\n",

-        "supply pf = 0.90\n"

-       ]

-      }

-     ],

-     "prompt_number": 32

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.12 Page No 80"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math \n",

-      "\n",

-      "#initialisation of variables\n",

-      "V_s=230.0    #V\n",

-      "R=1000.0      #ohm\n",

-      "R_D=20.0    #ohm\n",

-      "\n",

-      "#Calculations\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "I_om=V_m/(R+R_D)          \n",

-      "\n",

-      "#Results\n",

-      "print(\"Peak load current = %.2f A\" %I_om)\n",

-      "I_o=I_om/math.pi\n",

-      "print(\"dc load current = %.2f A\" %I_o)\n",

-      "V_D=I_o*R_D-V_m/math.pi\n",

-      "print(\"dc diode voltage = %.2f V\" %V_D)\n",

-      "V_on=V_m/math.pi\n",

-      "print(\"at no load, load voltage = %.2f V\" %V_on)\n",

-      "V_o1=I_o*R    \n",

-      "print(\"at given load, load voltage = %.2f V\" %V_o1)\n",

-      "vr=(V_on-V_o1)*100/V_on    \n",

-      "print(\"Voltage regulation(in percent)=%.2f\" %vr)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Peak load current = 0.32 A\n",

-        "dc load current = 0.10 A\n",

-        "dc diode voltage = -101.51 V\n",

-        "at no load, load voltage = 103.54 V\n",

-        "at given load, load voltage = 101.51 V\n",

-        "Voltage regulation(in percent)=1.96\n"

-       ]

-      }

-     ],

-     "prompt_number": 33

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.13 Page No 82"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_L=6.8   #V\n",

-      "V_smax=20*1.2    #V\n",

-      "V_smin=20*.8     #V\n",

-      "I_Lmax=30*1.5   #mA\n",

-      "I_Lmin=30*0.5  #mA\n",

-      "I_z=1          #mA\n",

-      "\n",

-      "#Calculations\n",

-      "R_smax=(V_smax-V_L)/((I_Lmin+I_z)*10**-3)\n",

-      "print(\"max source resistance = %.2f ohm\" %R_smax)\n",

-      "R_smin=(V_smin-V_L)/((I_Lmax+I_z)*10**-3)    \n",

-      "print(\"Min source resistance = %.2f ohm\" %R_smin)  #in book solution, error is committed in putting the values in formulea(printing error) but solution is correct\n",

-      "R_Lmax=V_L*1000/I_Lmin\n",

-      "print(\"Max load resistance = %.2f ohm\" %R_Lmax)\n",

-      "R_Lmin=V_L*1000/I_Lmax    \n",

-      "V_d=0.6      #V\n",

-      "V_r=V_L-V_d\n",

-      "\n",

-      "#Results\n",

-      "print(\"Min load resistance=%.2f ohm\" %R_Lmin)\n",

-      "print(\"Voltage rating of zener diode=%.2f V\" %V_r)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "max source resistance = 1075.00 ohm\n",

-        "Min source resistance = 200.00 ohm\n",

-        "Max load resistance = 453.33 ohm\n",

-        "Min load resistance=151.11 ohm\n",

-        "Voltage rating of zener diode=6.20 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 34

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.14 Page No 83"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "I2=200*10**-6      #A\n",

-      "V_z=20       #V\n",

-      "R_G=500.0   #hm\n",

-      "\n",

-      "#Calculations\n",

-      "R2=(V_z/I2)-R_G\n",

-      "print(\"R2=%.2f kilo-ohm\" %(R2/1000))\n",

-      "\n",

-      "V_v=25      #V\n",

-      "I1=I2\n",

-      "R1=(V_v-V_z)/I1\n",

-      "\n",

-      "#Results\n",

-      "print(\"R1=%.0f kilo-ohm\"%(R1/1000))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "R2=99.50 kilo-ohm\n",

-        "R1=25 kilo-ohm\n"

-       ]

-      }

-     ],

-     "prompt_number": 35

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.15, Page No 92"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "V_s=2*230          #V\n",

-      "\n",

-      "#Calculations\n",

-      "V_o=(math.sqrt(2)*V_s)/math.pi\n",

-      "R=60                #ohm\n",

-      "P_dc=(V_o)**2/R\n",

-      "TUF=0.2865\n",

-      "VA=P_dc/TUF\n",

-      "\n",

-      "#RESULTS\n",

-      "print(\"kVA rating of the transformer = %.2f kVA\" %(VA/1000));\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "kVA rating of the transformer = 2.49 kVA\n"

-       ]

-      }

-     ],

-     "prompt_number": 36

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.16, Page No 92"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "tr=0.5       #turns ratio\n",

-      "I_o=10.0\n",

-      "V=230.0\n",

-      "V_s=V/tr\n",

-      "\n",

-      "#Calculations\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "V_o=2*V_m/math.pi\n",

-      "phi1=0\n",

-      "#displacemnt angle=0 as fundamnetal component of i/p source current in phase with source voltage\n",

-      "DF=math.cos(math.radians(phi1))\n",

-      "I_s1=4*I_o/(math.sqrt(2)*math.pi)\n",

-      "I_s=math.sqrt(I_o**2*math.pi/math.pi)\n",

-      "CDF=I_s1/I_o\n",

-      "pf=CDF*DF\n",

-      "HF=math.sqrt((I_s/I_s1)**2-1)\n",

-      "CF=I_o/I_s\n",

-      "\n",

-      "#Results\n",

-      "print(\"o/p voltage = %.2f V\" %V_o)\n",

-      "print(\"distortion factor = %.2f\" %DF)\n",

-      "print(\"i/p pf=%.2f\" %pf)\n",

-      "print(\"Current displacent factor=%.2f\" %CDF)\n",

-      "print(\"Harmonic factor = %.2f\" %HF)\n",

-      "print(\"Creast factor = %.2f\" %CF)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "o/p voltage = 414.15 V\n",

-        "distortion factor = 1.00\n",

-        "i/p pf=0.90\n",

-        "Current displacent factor=0.90\n",

-        "Harmonic factor = 0.48\n",

-        "Creast factor = 1.00\n"

-       ]

-      }

-     ],

-     "prompt_number": 37

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.17, Page No 94"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_o=230.0\n",

-      "R=10.0\n",

-      "V_s=V_o*math.pi/(2*math.sqrt(2))\n",

-      "I_o=V_o/R\n",

-      "I_m=math.sqrt(2)*V_s/R\n",

-      "I_DAV=I_m/math.pi\n",

-      "\n",

-      "#Calculations\n",

-      "#avg value of diode current\n",

-      "I_Dr=I_m/2\n",

-      "PIV=math.sqrt(2)*V_s\n",

-      "I_s=I_m/math.sqrt(2)\n",

-      "TF=V_s*I_s\n",

-      "\n",

-      "#Results\n",

-      "print(\"peak diode current=%.2f A\" %I_m)\n",

-      "print(\"I_DAV=%.2f A\" %I_DAV)\n",

-      "print(\"I_Dr=%.2f A\" %I_Dr)   #rms value of diode current\n",

-      "print(\"PIV=%.1f V\" %PIV)\n",

-      "print(\"Transformer rating = %.2f kVA\" %(TF/1000))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "peak diode current=36.13 A\n",

-        "I_DAV=11.50 A\n",

-        "I_Dr=18.06 A\n",

-        "PIV=361.3 V\n",

-        "Transformer rating = 6.53 kVA\n"

-       ]

-      }

-     ],

-     "prompt_number": 38

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.18, Page No 103"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "tr=5\n",

-      "V=1100.0\n",

-      "R=10.0\n",

-      "\n",

-      "\n",

-      "#Calculations\n",

-      "print(\"In case of 3ph-3pulse type\")\n",

-      "V_ph=V/tr\n",

-      "V_mp=math.sqrt(2)*V_ph\n",

-      "V_o=3*math.sqrt(3)*V_mp/(2*math.pi)\n",

-      "print(\"avg o/p voltage=%.1f V\" %V_o)\n",

-      "I_mp=V_mp/R\n",

-      "I_D=(I_mp/math.pi)*math.sin(math.pi/3)    \n",

-      "print(\"\\navg value of diode current=%.3f A\" %I_D)\n",

-      "I_Dr=I_mp*math.sqrt((1/(2*math.pi))*(math.pi/3+.5*math.sin(2*math.pi/3)))    \n",

-      "print(\"\\nrms value of diode current=%.2f A\" %I_Dr)\n",

-      "V_or=V_mp*math.sqrt((3/(2*math.pi))*(math.pi/3+.5*math.sin(2*math.pi/3)))\n",

-      "P=(V_or**2)/R   \n",

-      "print(\"\\npower delivered=%.1f W\" %P)\n",

-      "print(\"in case of 3ph-M6 type\")\n",

-      "V_ph=V_ph/2\n",

-      "V_mp=math.sqrt(2)*V_ph\n",

-      "V_o=3*V_mp/(math.pi)  \n",

-      "I_mp=V_mp/R\n",

-      "I_D=(I_mp/math.pi)*math.sin(math.pi/6)    \n",

-      "I_Dr=I_mp*math.sqrt((1/(2*math.pi))*(math.pi/6+.5*math.sin(2*math.pi/6)))  \n",

-      "V_or=V_mp*math.sqrt((6/(2*math.pi))*(math.pi/6+.5*math.sin(2*math.pi/6)))\n",

-      "P=(V_or**2)/R   \n",

-      "\n",

-      "#Results\n",

-      "print(\"avg o/p voltage=%.2f V\" %V_o)\n",

-      "print(\"\\navg value of diode current=%.2f A\" %I_D)\n",

-      "print(\"\\nrms value of diode current=%.2f A\" %I_Dr)\n",

-      "print(\"\\npower delivered=%.0f W\" %P)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "In case of 3ph-3pulse type\n",

-        "avg o/p voltage=257.3 V\n",

-        "\n",

-        "avg value of diode current=8.577 A\n",

-        "\n",

-        "rms value of diode current=15.10 A\n",

-        "\n",

-        "power delivered=6841.3 W\n",

-        "in case of 3ph-M6 type\n",

-        "avg o/p voltage=148.55 V\n",

-        "\n",

-        "avg value of diode current=2.48 A\n",

-        "\n",

-        "rms value of diode current=6.07 A\n",

-        "\n",

-        "power delivered=2211 W\n"

-       ]

-      }

-     ],

-     "prompt_number": 39

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.19, Page No 115"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_o=400\n",

-      "R=10\n",

-      "\n",

-      "#Calculations\n",

-      "V_ml=V_o*math.pi/3\n",

-      "V_s=V_ml/(math.sqrt(2)*math.sqrt(3))\n",

-      "I_m=V_ml/R\n",

-      "I_s=.7804*I_m\n",

-      "tr=3*V_s*I_s   \n",

-      "\n",

-      "#Results\n",

-      "print(\"transformer rating=%.1f VA\" %tr)\n",

-      "I_Dr=.5518*I_m   \n",

-      "print(\"\\nrms value of diode current=%.3f A\" %I_Dr)\n",

-      "I_D=I_m/math.pi   \n",

-      "print(\"\\navg value of diode current=%.3f A\" %I_D)\n",

-      "print(\"\\npeak diode current=%.2f A\" %I_m)\n",

-      "PIV=V_ml \n",

-      "print(\"\\nPIV=%.2f V\" %PIV)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "transformer rating=16770.3 VA\n",

-        "\n",

-        "rms value of diode current=23.114 A\n",

-        "\n",

-        "avg value of diode current=13.333 A\n",

-        "\n",

-        "peak diode current=41.89 A\n",

-        "\n",

-        "PIV=418.88 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 40

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.20, Page No 116"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_l=230\n",

-      "E=240\n",

-      "R=8\n",

-      "\n",

-      "#Calculations\n",

-      "V_ml=math.sqrt(2)*V_l\n",

-      "V_o=3*V_ml/math.pi\n",

-      "I_o=(V_o-E)/R\n",

-      "P_b=E*I_o    \n",

-      "P_d=E*I_o+I_o**2*R   \n",

-      "phi1=0\n",

-      "math.cos(math.radians(phi1))\n",

-      "I_s1=2*math.sqrt(3)*I_o/(math.sqrt(2)*math.pi)\n",

-      "I_s=math.sqrt(I_o**2*2*math.pi/(3*math.pi))\n",

-      "CDF=I_s1/I_s    \n",

-      "pf=DF*CDF    \n",

-      "HF=math.sqrt(CDF**-2-1)   \n",

-      "tr=math.sqrt(3)*V_l*I_o*math.sqrt(2/3)\n",

-      "\n",

-      "#Results\n",

-      "print(\"Power delivered to battery=%.1f W\" %P_b)\n",

-      "print(\"Power delivered to load=%.2f W\" %P_d)\n",

-      "print(\"Displacement factor=%.2f\" %DF)\n",

-      "print(\"Current distortion factor=%.3f\" %CDF)\n",

-      "print(\"i/p pf=%.3f\"%pf)\n",

-      "print(\"Harmonic factor=%.2f\" %HF)\n",

-      "print(\"Tranformer rating=%.2f VA\" %tr)\n",

-      "#answers have small variations from the book due to difference in rounding off of digits"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Power delivered to battery=2118.3 W\n",

-        "Power delivered to load=2741.48 W\n",

-        "Displacement factor=1.00\n",

-        "Current distortion factor=0.955\n",

-        "i/p pf=0.955\n",

-        "Harmonic factor=0.31\n",

-        "Tranformer rating=0.00 VA\n"

-       ]

-      }

-     ],

-     "prompt_number": 41

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.21, Page No 122"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "f=50  #Hz\n",

-      "V=230.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_m=math.sqrt(2)*V\n",

-      "R=400.0\n",

-      "RF=0.05\n",

-      "C=(1/(4*f*R))*(1+(1/(math.sqrt(2)*RF)))\n",

-      "\n",

-      "#Results\n",

-      "print(\"capacitor value=%.2f uF\" %(C/10**-6))\n",

-      "V_o=V_m*(1-1/(4*f*R*C))\n",

-      "print(\"o/p voltage with filter=%.2f V\" %V_o)\n",

-      "V_o=2*V_m/math.pi   \n",

-      "print(\"o/p voltage without filter=%.2f V\" %V_o)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "capacitor value=189.28 uF\n",

-        "o/p voltage with filter=303.79 V\n",

-        "o/p voltage without filter=207.07 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 42

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.22, Page No 122"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "f=50\n",

-      "CRF=0.05\n",

-      "R=300\n",

-      "\n",

-      "#Calculations\n",

-      "L=math.sqrt((CRF/(.4715*R))**-2-R**2)/(2*2*math.pi*f)    \n",

-      "print(\"L=%.2f H\" %L)\n",

-      "R=30\n",

-      "L=math.sqrt((CRF/(.4715*R))**-2-R**2)/(2*2*math.pi*f)    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"\\nL=%.2f H\" %L)\n",

-      "L=0\n",

-      "CRF=.4715*R/math.sqrt(R**2+(2*2*math.pi*f*L)**2)   \n",

-      "print(\"\\nCRF=%.2f\" %CRF)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "L=4.48 H\n",

-        "\n",

-        "L=0.45 H\n",

-        "\n",

-        "CRF=0.47\n"

-       ]

-      }

-     ],

-     "prompt_number": 43

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 3.23, Page No 127"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "R=50\n",

-      "L_L=10*10**-3\n",

-      "f=50.0\n",

-      "w=2*math.pi*f\n",

-      "\n",

-      "#Calculations\n",

-      "C=10/(2*w*math.sqrt(R**2+(2*w*L_L)**2))\n",

-      "\n",

-      "#Results\n",

-      "print(\"C=%.2f uF\" %(C*10**6))\n",

-      "VRF=0.1\n",

-      "L=(1/(4*w**2*C))*((math.sqrt(2)/(3*VRF))+1)\n",

-      "print(\"\\nL=%.2f mH\" %(L*10**3))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "C=315.83 uF\n",

-        "\n",

-        "L=45.83 mH\n"

-       ]

-      }

-     ],

-     "prompt_number": 44

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Power_Electronics/Chapter4.ipynb b/_Power_Electronics/Chapter4.ipynb
deleted file mode 100755
index 22311574..00000000
--- a/_Power_Electronics/Chapter4.ipynb
+++ /dev/null
@@ -1,946 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 04 : Thyristors"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.3, Page No 149"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "P=.5    #P=V_g*I_g\n",

-      "s=130    #s=V_g/I_g\n",

-      "\n",

-      "#Calculations\n",

-      "I_g=math.sqrt(P/s)\n",

-      "V_g=s*I_g\n",

-      "E=15\n",

-      "R_s=(E-V_g)/I_g    \n",

-      "\n",

-      "#Results\n",

-      "print(\"Gate source resistance=%.2f ohm\" %R_s)\n",

-      "#Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Gate source resistance=111.87 ohm\n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.4, Page No 149"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "\n",

-      "R_s=120     #slope of load line is -120V/A. This gives gate source resistance\n",

-      "print(\"gate source resistance=%.0f ohm\" %R_s)\n",

-      "\n",

-      "P=.4     #P=V_g*I_g\n",

-      "E_s=15\n",

-      "\n",

-      "#Calculations\n",

-      " #E_s=I_g*R_s+V_g %    after solving this\n",

-      " #120*I_g**2-15*I_g+0.4=0    so\n",

-      "a=120   \n",

-      "b=-15\n",

-      "c=0.4\n",

-      "D=math.sqrt((b**2)-4*a*c)\n",

-      "I_g=(-b+D)/(2*a)   \n",

-      "V_g=P/I_g\n",

-      "\n",

-      "#Results\n",

-      "print(\"\\ntrigger current=%.2f mA\" %(I_g*10**3))    \n",

-      "print(\"\\nthen trigger voltage=%.3f V\" %V_g)\n",

-      "I_g=(-b-D)/(2*a)   \n",

-      "V_g=P/I_g\n",

-      "print(\"\\ntrigger current=%.2f mA\" %(I_g*10**3))    \n",

-      "print(\"\\nthen trigger voltage=%.2f V\" %V_g)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "gate source resistance=120 ohm\n",

-        "\n",

-        "trigger current=86.44 mA\n",

-        "\n",

-        "then trigger voltage=4.628 V\n",

-        "\n",

-        "trigger current=38.56 mA\n",

-        "\n",

-        "then trigger voltage=10.37 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 2

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.5 Page No 150"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "\n",

-      "#V_g=1+10*I_g\n",

-      "P_gm=5     #P_gm=V_g*I_g\n",

-      "#after solving % eqn becomes 10*I_g**2+I_g-5=0\n",

-      "a=10.0    \n",

-      "b=1.0    \n",

-      "c=-5\n",

-      "\n",

-      "#Calculations\n",

-      "I_g=(-b+math.sqrt(b**2-4*a*c))/(2*a)\n",

-      "E_s=15\n",

-      "#using E_s=R_s*I_g+V_g\n",

-      "R_s=(E_s-1)/I_g-10   \n",

-      "P_gav=.3     #W\n",

-      "T=20*10**-6\n",

-      "f=P_gav/(P_gm*T)\n",

-      "dl=f*T\n",

-      "\n",

-      "#Results\n",

-      "print(\"Reistance=%.3f ohm\" %R_s)\n",

-      "print(\"Triggering freq=%.0f kHz\" %(f/1000))\n",

-      "print(\"Tduty cycle=%.2f\" %dl)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Reistance=11.248 ohm\n",

-        "Triggering freq=3 kHz\n",

-        "Tduty cycle=0.06\n"

-       ]

-      }

-     ],

-     "prompt_number": 3

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.6, Page No 151"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "I=.1\n",

-      "E=200.0\n",

-      "L=0.2\n",

-      "\n",

-      "#Calculations\n",

-      "t=I*L/E   \n",

-      "R=20.0\n",

-      "t1=(-L/R)*math.log(1-(R*I/E))    \n",

-      "L=2.0\n",

-      "t2=(-L/R)*math.log(1-(R*I/E))   \n",

-      "\n",

-      "#Results\n",

-      "print(\"in case load consists of (a)L=.2H\")\n",

-      "print(\"min gate pulse width=%.0f us\" %(t*10**6))\n",

-      "print(\"(b)R=20ohm in series with L=.2H\")\n",

-      "print(\"min gate pulse width=%.3f us\" %(t1*10**6))\n",

-      "print(\"(c)R=20ohm in series with L=2H\")\n",

-      "print(\"min gate pulse width=%.2f us\" %(t2*10**6))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "in case load consists of (a)L=.2H\n",

-        "min gate pulse width=100 us\n",

-        "(b)R=20ohm in series with L=.2H\n",

-        "min gate pulse width=100.503 us\n",

-        "(c)R=20ohm in series with L=2H\n",

-        "min gate pulse width=1005.03 us\n"

-       ]

-      }

-     ],

-     "prompt_number": 4

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.9 Page No 163"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "\n",

-      "def theta(th):\n",

-      "    I_m=1     #supposition\n",

-      "    I_av=(I_m/(2*math.pi))*(1+math.cos(math.radians(th)))\n",

-      "    I_rms=math.sqrt((I_m/(2*math.pi))*((180-th)*math.pi/360+.25*math.sin(math.radians(2*th))))\n",

-      "    FF=I_rms/I_av\n",

-      "    I_rms=35\n",

-      "    I_TAV=I_rms/FF\n",

-      "    return I_TAV\n",

-      "\n",

-      "#Calculations\n",

-      "print(\"when conduction angle=180\")\n",

-      "th=0\n",

-      "I_TAV=theta(th)\n",

-      "print(\"avg on current rating=%.3f A\" %I_TAV)\n",

-      "print(\"when conduction angle=90\")\n",

-      "th=90\n",

-      "I_TAV=theta(th)\n",

-      "\n",

-      "#Results\n",

-      "print(\"avg on current rating=%.3f A\" %I_TAV)\n",

-      "print(\"when conduction angle=30\")\n",

-      "th=150\n",

-      "I_TAV=theta(th)\n",

-      "print(\"avg on current rating=%.3f A\" %I_TAV)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "when conduction angle=180\n",

-        "avg on current rating=22.282 A\n",

-        "when conduction angle=90\n",

-        "avg on current rating=15.756 A\n",

-        "when conduction angle=30\n",

-        "avg on current rating=8.790 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 5

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.10, Page No 164"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "\n",

-      "def theta(th):\n",

-      "    n=360.0/th\n",

-      "    I=1.0     #supposition\n",

-      "    I_av=I/n\n",

-      "    I_rms=I/math.sqrt(n)\n",

-      "    FF=I_rms/I_av\n",

-      "    I_rms=35\n",

-      "    I_TAV=I_rms/FF\n",

-      "    return I_TAV\n",

-      "\n",

-      "#Calculations\n",

-      "th=180.0\n",

-      "I_TAV1=theta(th)\n",

-      "th=90.0\n",

-      "I_TAV2=theta(th)\n",

-      "th=30.0\n",

-      "I_TAV3=theta(th)\n",

-      "\n",

-      "#Results\n",

-      "print(\"when conduction angle=180\")\n",

-      "print(\"avg on current rating=%.3f A\" %I_TAV)\n",

-      "print(\"when conduction angle=90\")\n",

-      "print(\"avg on current rating=%.1f A\" %I_TAV2)\n",

-      "print(\"when conduction angle=30\")\n",

-      "print(\"avg on current rating=%.4f A\" %I_TAV3)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "when conduction angle=180\n",

-        "avg on current rating=8.790 A\n",

-        "when conduction angle=90\n",

-        "avg on current rating=17.5 A\n",

-        "when conduction angle=30\n",

-        "avg on current rating=10.1036 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 6

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.11 Page No 165"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math \n",

-      "\n",

-      "#initialisation of variables\n",

-      "f=50.0     #Hz\n",

-      "\n",

-      "#Calculations\n",

-      "I_sb=3000.0\n",

-      "t=1/(4*f)\n",

-      "T=1/(2*f)\n",

-      "I=math.sqrt(I_sb**2*t/T)    \n",

-      "r=(I_sb/math.sqrt(2))**2*T   \n",

-      "\n",

-      "#Results\n",

-      "print(\"surge current rating=%.2f A\" %I)\n",

-      "print(\"\\nI**2*t rating=%.0f A^2.s\" %r)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "surge current rating=2121.32 A\n",

-        "\n",

-        "I**2*t rating=45000 A^2.s\n"

-       ]

-      }

-     ],

-     "prompt_number": 7

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.12 Page No 165"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "\n",

-      "V_s=300.0 #V\n",

-      "R=60.0 #ohm\n",

-      "L=2.0 #H\n",

-      "\n",

-      "#Calculations\n",

-      "t=40*10**-6 #s\n",

-      "i_T=(V_s/R)*(1-math.exp(-R*t/L))\n",

-      "i=.036 #A\n",

-      "R1=V_s/(i-i_T)\n",

-      "\n",

-      "#Results\n",

-      "print(\"maximum value of remedial parameter=%.3f kilo-ohm\" %(R1/1000))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "maximum value of remedial parameter=9.999 kilo-ohm\n"

-       ]

-      }

-     ],

-     "prompt_number": 8

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.16 Page No 172"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "V_p=230.0*math.sqrt(2)\n",

-      "\n",

-      "#Calculations\n",

-      "R=1+((1)**-1+(10)**-1)**-1\n",

-      "A=V_p/R\n",

-      "s=1     #s\n",

-      "t_c=20*A**-2*s\n",

-      "\n",

-      "#Results\n",

-      "print(\"fault clearance time=%.4f ms\" %(t_c*10**3))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "fault clearance time=0.6890 ms\n"

-       ]

-      }

-     ],

-     "prompt_number": 9

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.17, Page No 176"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "\n",

-      "V_s=math.sqrt(2)*230     #V\n",

-      "L=15*10**-6     #H\n",

-      "I=V_s/L     #I=(di/dt)_max\n",

-      "R_s=10   #ohm\n",

-      "v=I*R_s     #v=(dv/dt)_max\n",

-      "\n",

-      "#Calculations\n",

-      "f=50     #Hz\n",

-      "X_L=L*2*math.pi*f\n",

-      "R=2\n",

-      "I_max=V_s/(R+X_L)    \n",

-      "FF=math.pi/math.sqrt(2)\n",

-      "I_TAV1=I_max/FF    \n",

-      "FF=3.98184\n",

-      "I_TAV2=I_max/FF    \n",

-      "\n",

-      "\n",

-      "#RESULTS\n",

-      "print(\"(di/dt)_max=%.3f A/usec\" %(I/10**6))\n",

-      "print(\"\\n(dv/dt)_max=%.2f V/usec\" %(v/10**6))\n",

-      "print(\"\\nI_rms=%.3f A\" %I_max)\n",

-      "print(\"when conduction angle=90\")\n",

-      "print(\"I_TAV=%.3f A\" %I_TAV1)\n",

-      "print(\"when conduction angle=30\")\n",

-      "print(\"I_TAV=%.3f A\" %I_TAV2)\n",

-      "print(\"\\nvoltage rating=%.3f V\" %(2.75*V_s)) #rating is taken 2.75 times of peak working voltage unlike 2.5 to 3 times as mentioned int book."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "(di/dt)_max=21.685 A/usec\n",

-        "\n",

-        "(dv/dt)_max=216.85 V/usec\n",

-        "\n",

-        "I_rms=162.252 A\n",

-        "when conduction angle=90\n",

-        "I_TAV=73.039 A\n",

-        "when conduction angle=30\n",

-        "I_TAV=40.748 A\n",

-        "\n",

-        "voltage rating=894.490 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 10

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.19, Page No 186"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "\n",

-      "T_jm=125\n",

-      "th_jc=.15     #degC/W\n",

-      "th_cs=0.075     #degC/W\n",

-      "\n",

-      "\n",

-      "#Calculations\n",

-      "dT=54     #dT=T_s-T_a\n",

-      "P_av=120\n",

-      "th_sa=dT/P_av\n",

-      "T_a=40     #ambient temp\n",

-      "P_av=(T_jm-T_a)/(th_sa+th_jc+th_cs)\n",

-      "if (P_av-120)<1 :\n",

-      "    print(\"selection of heat sink is satisfactory\")\n",

-      "\n",

-      "dT=58     #dT=T_s-T_a\n",

-      "P_av=120\n",

-      "th_sa=dT/P_av\n",

-      "T_a=40     #ambient temp\n",

-      "P_av=(T_jm-T_a)/(th_sa+th_jc+th_cs)\n",

-      "if (P_av-120)<1 :\n",

-      "    print(\"selection of heat sink is satisfactory\")\n",

-      "\n",

-      "V_m=math.sqrt(2)*230\n",

-      "R=2\n",

-      "I_TAV=V_m/(R*math.pi)\n",

-      "P_av=90\n",

-      "th_sa=(T_jm-T_a)/P_av-(th_jc+th_cs)\n",

-      "dT=P_av*th_sa\n",

-      "print(\"for heat sink\")    \n",

-      "print(\"T_s-T_a=%.2f degC\" %dT)   \n",

-      "print(\"\\nP_av=%.0f W\" %P_av)\n",

-      "P=(V_m/2)**2/R\n",

-      "eff=P/(P+P_av)   \n",

-      "print(\"\\nckt efficiency=%.3f pu\" %eff)\n",

-      "a=60     #delay angle\n",

-      "I_TAV=(V_m/(2*math.pi*R))*(1+math.cos(math.radians(a)))\n",

-      "print(\"\\nI_TAV=%.2f A\" %I_TAV)\n",

-      "dT=46\n",

-      "T_s=dT+T_a\n",

-      "T_c=T_s+P_av*th_cs    \n",

-      "T_j=T_c+P_av*th_jc    \n",

-      "\n",

-      "#Results\n",

-      "print(\"\\ncase temp=%.2f degC\" %T_c)\n",

-      "print(\"\\njunction temp=%.2f degC\" %T_j)\n",

-      "\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for heat sink\n",

-        "T_s-T_a=-20.25 degC\n",

-        "\n",

-        "P_av=90 W\n",

-        "\n",

-        "ckt efficiency=0.993 pu\n",

-        "\n",

-        "I_TAV=38.83 A\n",

-        "\n",

-        "case temp=92.75 degC\n",

-        "\n",

-        "junction temp=106.25 degC\n"

-       ]

-      }

-     ],

-     "prompt_number": 11

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.20, Page No 187"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "T_j=125.0     #degC\n",

-      "T_s=70.0     #degC\n",

-      "th_jc=.16     #degC/W\n",

-      "th_cs=.08     #degC/W\n",

-      "\n",

-      "#Calculations\n",

-      "P_av1=(T_j-T_s)/(th_jc+th_cs)    \n",

-      "\n",

-      "T_s=60     #degC\n",

-      "P_av2=(T_j-T_s)/(th_jc+th_cs)    \n",

-      "inc=(math.sqrt(P_av2)-math.sqrt(P_av1))*100/math.sqrt(P_av1)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"Total avg power loss in thristor sink combination=%.2f W\" %P_av1)\n",

-      "print(\"Percentage inc in rating=%.2f\" %inc)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Total avg power loss in thristor sink combination=229.17 W\n",

-        "Percentage inc in rating=8.71\n"

-       ]

-      }

-     ],

-     "prompt_number": 12

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.21, Page No 197"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "\n",

-      "R=25000.0\n",

-      "I_l1=.021     #I_l=leakage current\n",

-      "I_l2=.025\n",

-      "I_l3=.018\n",

-      "I_l4=.016\n",

-      " #V1=(I-I_l1)*R\n",

-      " #V2=(I-I_l2)*R\n",

-      " #V3=(I-I_l3)*R\n",

-      " #V4=(I-I_l4)*R\n",

-      " #V=V1+V2+V3+V4\n",

-      "    \n",

-      "#Calculations\n",

-      "V=10000.0\n",

-      "I_l=I_l1+I_l2+I_l3+I_l4\n",

-      " #after solving\n",

-      "I=((V/R)+I_l)/4\n",

-      "R_c=40.0\n",

-      "V1=(I-I_l1)*R    \n",

-      "\n",

-      "#Resluts\n",

-      "print(\"voltage across SCR1=%.0f V\" %V1)\n",

-      "V2=(I-I_l2)*R    \n",

-      "print(\"\\nvoltage across SCR2=%.0f V\" %V2)\n",

-      "V3=(I-I_l3)*R    \n",

-      "print(\"\\nvoltage across SCR3=%.0f V\" %V3)\n",

-      "V4=(I-I_l4)*R    \n",

-      "print(\"\\nvoltage across SCR4=%.0f V\" %V4)\n",

-      "\n",

-      "I1=V1/R_c    \n",

-      "print(\"\\ndischarge current through SCR1=%.3f A\" %I1)\n",

-      "I2=V2/R_c   \n",

-      "print(\"\\ndischarge current through SCR2=%.3f A\" %I2)\n",

-      "I3=V3/R_c    \n",

-      "print(\"\\ndischarge current through SCR3=%.3f A\" %I3)\n",

-      "I4=V4/R_c    \n",

-      "print(\"\\ndischarge current through SCR4=%.3f A\" %I4)\n",

-      "\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "voltage across SCR1=2475 V\n",

-        "\n",

-        "voltage across SCR2=2375 V\n",

-        "\n",

-        "voltage across SCR3=2550 V\n",

-        "\n",

-        "voltage across SCR4=2600 V\n",

-        "\n",

-        "discharge current through SCR1=61.875 A\n",

-        "\n",

-        "discharge current through SCR2=59.375 A\n",

-        "\n",

-        "discharge current through SCR3=63.750 A\n",

-        "\n",

-        "discharge current through SCR4=65.000 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 13

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.22, Page No 198"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_r=1000     #rating of SCR\n",

-      "I_r=200     #rating of SCR\n",

-      "V_s=6000     #rating of String\n",

-      "I_s=1000     #rating of String\n",

-      "\n",

-      "#Calculations\n",

-      "print(\"when DRF=.1\")\n",

-      "DRF=.1\n",

-      "n_s=V_s/(V_r*(1-DRF))    \n",

-      "print(\"number of series units=%.0f\" %math.ceil(n_s))\n",

-      "n_p=I_s/(I_r*(1-DRF))    \n",

-      "print(\"\\nnumber of parrallel units=%.0f\" %math.ceil(n_p))\n",

-      "print(\"when DRF=.2\")\n",

-      "DRF=.2\n",

-      "\n",

-      "#Results\n",

-      "n_s=V_s/(V_r*(1-DRF))   \n",

-      "print(\"number of series units=%.0f\" %math.ceil(n_s))\n",

-      "n_p=I_s/(I_r*(1-DRF))    \n",

-      "print(\"\\nnumber of parrallel units=%.0f\" %math.ceil(n_p))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "when DRF=.1\n",

-        "number of series units=7\n",

-        "\n",

-        "number of parrallel units=6\n",

-        "when DRF=.2\n",

-        "number of series units=8\n",

-        "\n",

-        "number of parrallel units=7\n"

-       ]

-      }

-     ],

-     "prompt_number": 14

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.23, Page No 198"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V1=1.6     #on state voltage drop of SCR1\n",

-      "V2=1.2     #on state voltage drop of SCR2\n",

-      "I1=250.0     #current rating of SCR1\n",

-      "I2=350.0     #current rating of SCR2\n",

-      "\n",

-      "#Calculations\n",

-      "R1=V1/I1\n",

-      "R2=V2/I2\n",

-      "I=600.0     #current to be shared\n",

-      " #for SCR1 %     I*(R1+R)/(total resistance)=k*I1                    (1)\n",

-      " #for SCR2 %     I*(R2+R)/(total resistance)=k*I2                    (2)\n",

-      " #(1)/(2)\n",

-      "R=(R2*I2-R1*I1)/(I1-I2)\n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"RSequired value of resistance=%.3f ohm\" %R)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "RSequired value of resistance=0.004 ohm\n"

-       ]

-      }

-     ],

-     "prompt_number": 15

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.25, Page No 223"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "f=2000.0     #Hz\n",

-      "C=0.04*10**-6\n",

-      "n=.72\n",

-      "\n",

-      "#Calculations\n",

-      "R=1/(f*C*math.log(1/(1-n)))    \n",

-      "V_p=18\n",

-      "V_BB=V_p/n\n",

-      "R2=10**4/(n*V_BB)    \n",

-      "I=4.2*10**-3     #leakage current\n",

-      "R_BB=5000\n",

-      "R1=(V_BB/I)-R2-R_BB\n",

-      "\n",

-      "#Results\n",

-      "print(\"R=%.2f kilo-ohm\" %(R/1000))\n",

-      "print(\"\\nR2=%.2f ohm\" %R2)\n",

-      "print(\"\\nR1=%.0f ohm\" %R1)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "R=9.82 kilo-ohm\n",

-        "\n",

-        "R2=555.56 ohm\n",

-        "\n",

-        "R1=397 ohm\n"

-       ]

-      }

-     ],

-     "prompt_number": 16

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.26, Page No 223"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "\n",

-      "V_p=18.0\n",

-      "n=.72\n",

-      "V_BB=V_p/n\n",

-      "I_p=.6*10**-3\n",

-      "I_v=2.5*10**-3\n",

-      "V_v=1\n",

-      "\n",

-      "#Calculations\n",

-      "R_max=V_BB*(1-n)/I_p    \n",

-      "print(\"R_max=%.2f kilo-ohm\" %(R_max/1000))\n",

-      "R_min=(V_BB-V_v)/I_v    \n",

-      "print(\"\\nR_min=%.2f kilo-ohm\" %(R_min/1000))\n",

-      "\n",

-      "C=.04*10**-6\n",

-      "f_min=1/(R_max*C*math.log(1/(1-n)))    \n",

-      "print(\"\\nf_min=%.3f kHz\" %(f_min/1000))\n",

-      "f_max=1/(R_min*C*math.log(1/(1-n)))    \n",

-      "print(\"\\nf_max=%.2f kHz\" %(f_max/1000))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "R_max=11.67 kilo-ohm\n",

-        "\n",

-        "R_min=9.60 kilo-ohm\n",

-        "\n",

-        "f_min=1.683 kHz\n",

-        "\n",

-        "f_max=2.05 kHz\n"

-       ]

-      }

-     ],

-     "prompt_number": 17

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Power_Electronics/Chapter4_1.ipynb b/_Power_Electronics/Chapter4_1.ipynb
deleted file mode 100755
index 22311574..00000000
--- a/_Power_Electronics/Chapter4_1.ipynb
+++ /dev/null
@@ -1,946 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 04 : Thyristors"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.3, Page No 149"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "P=.5    #P=V_g*I_g\n",

-      "s=130    #s=V_g/I_g\n",

-      "\n",

-      "#Calculations\n",

-      "I_g=math.sqrt(P/s)\n",

-      "V_g=s*I_g\n",

-      "E=15\n",

-      "R_s=(E-V_g)/I_g    \n",

-      "\n",

-      "#Results\n",

-      "print(\"Gate source resistance=%.2f ohm\" %R_s)\n",

-      "#Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Gate source resistance=111.87 ohm\n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.4, Page No 149"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "\n",

-      "R_s=120     #slope of load line is -120V/A. This gives gate source resistance\n",

-      "print(\"gate source resistance=%.0f ohm\" %R_s)\n",

-      "\n",

-      "P=.4     #P=V_g*I_g\n",

-      "E_s=15\n",

-      "\n",

-      "#Calculations\n",

-      " #E_s=I_g*R_s+V_g %    after solving this\n",

-      " #120*I_g**2-15*I_g+0.4=0    so\n",

-      "a=120   \n",

-      "b=-15\n",

-      "c=0.4\n",

-      "D=math.sqrt((b**2)-4*a*c)\n",

-      "I_g=(-b+D)/(2*a)   \n",

-      "V_g=P/I_g\n",

-      "\n",

-      "#Results\n",

-      "print(\"\\ntrigger current=%.2f mA\" %(I_g*10**3))    \n",

-      "print(\"\\nthen trigger voltage=%.3f V\" %V_g)\n",

-      "I_g=(-b-D)/(2*a)   \n",

-      "V_g=P/I_g\n",

-      "print(\"\\ntrigger current=%.2f mA\" %(I_g*10**3))    \n",

-      "print(\"\\nthen trigger voltage=%.2f V\" %V_g)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "gate source resistance=120 ohm\n",

-        "\n",

-        "trigger current=86.44 mA\n",

-        "\n",

-        "then trigger voltage=4.628 V\n",

-        "\n",

-        "trigger current=38.56 mA\n",

-        "\n",

-        "then trigger voltage=10.37 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 2

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.5 Page No 150"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "\n",

-      "#V_g=1+10*I_g\n",

-      "P_gm=5     #P_gm=V_g*I_g\n",

-      "#after solving % eqn becomes 10*I_g**2+I_g-5=0\n",

-      "a=10.0    \n",

-      "b=1.0    \n",

-      "c=-5\n",

-      "\n",

-      "#Calculations\n",

-      "I_g=(-b+math.sqrt(b**2-4*a*c))/(2*a)\n",

-      "E_s=15\n",

-      "#using E_s=R_s*I_g+V_g\n",

-      "R_s=(E_s-1)/I_g-10   \n",

-      "P_gav=.3     #W\n",

-      "T=20*10**-6\n",

-      "f=P_gav/(P_gm*T)\n",

-      "dl=f*T\n",

-      "\n",

-      "#Results\n",

-      "print(\"Reistance=%.3f ohm\" %R_s)\n",

-      "print(\"Triggering freq=%.0f kHz\" %(f/1000))\n",

-      "print(\"Tduty cycle=%.2f\" %dl)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Reistance=11.248 ohm\n",

-        "Triggering freq=3 kHz\n",

-        "Tduty cycle=0.06\n"

-       ]

-      }

-     ],

-     "prompt_number": 3

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.6, Page No 151"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "I=.1\n",

-      "E=200.0\n",

-      "L=0.2\n",

-      "\n",

-      "#Calculations\n",

-      "t=I*L/E   \n",

-      "R=20.0\n",

-      "t1=(-L/R)*math.log(1-(R*I/E))    \n",

-      "L=2.0\n",

-      "t2=(-L/R)*math.log(1-(R*I/E))   \n",

-      "\n",

-      "#Results\n",

-      "print(\"in case load consists of (a)L=.2H\")\n",

-      "print(\"min gate pulse width=%.0f us\" %(t*10**6))\n",

-      "print(\"(b)R=20ohm in series with L=.2H\")\n",

-      "print(\"min gate pulse width=%.3f us\" %(t1*10**6))\n",

-      "print(\"(c)R=20ohm in series with L=2H\")\n",

-      "print(\"min gate pulse width=%.2f us\" %(t2*10**6))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "in case load consists of (a)L=.2H\n",

-        "min gate pulse width=100 us\n",

-        "(b)R=20ohm in series with L=.2H\n",

-        "min gate pulse width=100.503 us\n",

-        "(c)R=20ohm in series with L=2H\n",

-        "min gate pulse width=1005.03 us\n"

-       ]

-      }

-     ],

-     "prompt_number": 4

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.9 Page No 163"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "\n",

-      "def theta(th):\n",

-      "    I_m=1     #supposition\n",

-      "    I_av=(I_m/(2*math.pi))*(1+math.cos(math.radians(th)))\n",

-      "    I_rms=math.sqrt((I_m/(2*math.pi))*((180-th)*math.pi/360+.25*math.sin(math.radians(2*th))))\n",

-      "    FF=I_rms/I_av\n",

-      "    I_rms=35\n",

-      "    I_TAV=I_rms/FF\n",

-      "    return I_TAV\n",

-      "\n",

-      "#Calculations\n",

-      "print(\"when conduction angle=180\")\n",

-      "th=0\n",

-      "I_TAV=theta(th)\n",

-      "print(\"avg on current rating=%.3f A\" %I_TAV)\n",

-      "print(\"when conduction angle=90\")\n",

-      "th=90\n",

-      "I_TAV=theta(th)\n",

-      "\n",

-      "#Results\n",

-      "print(\"avg on current rating=%.3f A\" %I_TAV)\n",

-      "print(\"when conduction angle=30\")\n",

-      "th=150\n",

-      "I_TAV=theta(th)\n",

-      "print(\"avg on current rating=%.3f A\" %I_TAV)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "when conduction angle=180\n",

-        "avg on current rating=22.282 A\n",

-        "when conduction angle=90\n",

-        "avg on current rating=15.756 A\n",

-        "when conduction angle=30\n",

-        "avg on current rating=8.790 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 5

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.10, Page No 164"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "\n",

-      "def theta(th):\n",

-      "    n=360.0/th\n",

-      "    I=1.0     #supposition\n",

-      "    I_av=I/n\n",

-      "    I_rms=I/math.sqrt(n)\n",

-      "    FF=I_rms/I_av\n",

-      "    I_rms=35\n",

-      "    I_TAV=I_rms/FF\n",

-      "    return I_TAV\n",

-      "\n",

-      "#Calculations\n",

-      "th=180.0\n",

-      "I_TAV1=theta(th)\n",

-      "th=90.0\n",

-      "I_TAV2=theta(th)\n",

-      "th=30.0\n",

-      "I_TAV3=theta(th)\n",

-      "\n",

-      "#Results\n",

-      "print(\"when conduction angle=180\")\n",

-      "print(\"avg on current rating=%.3f A\" %I_TAV)\n",

-      "print(\"when conduction angle=90\")\n",

-      "print(\"avg on current rating=%.1f A\" %I_TAV2)\n",

-      "print(\"when conduction angle=30\")\n",

-      "print(\"avg on current rating=%.4f A\" %I_TAV3)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "when conduction angle=180\n",

-        "avg on current rating=8.790 A\n",

-        "when conduction angle=90\n",

-        "avg on current rating=17.5 A\n",

-        "when conduction angle=30\n",

-        "avg on current rating=10.1036 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 6

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.11 Page No 165"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math \n",

-      "\n",

-      "#initialisation of variables\n",

-      "f=50.0     #Hz\n",

-      "\n",

-      "#Calculations\n",

-      "I_sb=3000.0\n",

-      "t=1/(4*f)\n",

-      "T=1/(2*f)\n",

-      "I=math.sqrt(I_sb**2*t/T)    \n",

-      "r=(I_sb/math.sqrt(2))**2*T   \n",

-      "\n",

-      "#Results\n",

-      "print(\"surge current rating=%.2f A\" %I)\n",

-      "print(\"\\nI**2*t rating=%.0f A^2.s\" %r)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "surge current rating=2121.32 A\n",

-        "\n",

-        "I**2*t rating=45000 A^2.s\n"

-       ]

-      }

-     ],

-     "prompt_number": 7

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.12 Page No 165"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "\n",

-      "V_s=300.0 #V\n",

-      "R=60.0 #ohm\n",

-      "L=2.0 #H\n",

-      "\n",

-      "#Calculations\n",

-      "t=40*10**-6 #s\n",

-      "i_T=(V_s/R)*(1-math.exp(-R*t/L))\n",

-      "i=.036 #A\n",

-      "R1=V_s/(i-i_T)\n",

-      "\n",

-      "#Results\n",

-      "print(\"maximum value of remedial parameter=%.3f kilo-ohm\" %(R1/1000))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "maximum value of remedial parameter=9.999 kilo-ohm\n"

-       ]

-      }

-     ],

-     "prompt_number": 8

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.16 Page No 172"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "V_p=230.0*math.sqrt(2)\n",

-      "\n",

-      "#Calculations\n",

-      "R=1+((1)**-1+(10)**-1)**-1\n",

-      "A=V_p/R\n",

-      "s=1     #s\n",

-      "t_c=20*A**-2*s\n",

-      "\n",

-      "#Results\n",

-      "print(\"fault clearance time=%.4f ms\" %(t_c*10**3))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "fault clearance time=0.6890 ms\n"

-       ]

-      }

-     ],

-     "prompt_number": 9

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.17, Page No 176"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "\n",

-      "V_s=math.sqrt(2)*230     #V\n",

-      "L=15*10**-6     #H\n",

-      "I=V_s/L     #I=(di/dt)_max\n",

-      "R_s=10   #ohm\n",

-      "v=I*R_s     #v=(dv/dt)_max\n",

-      "\n",

-      "#Calculations\n",

-      "f=50     #Hz\n",

-      "X_L=L*2*math.pi*f\n",

-      "R=2\n",

-      "I_max=V_s/(R+X_L)    \n",

-      "FF=math.pi/math.sqrt(2)\n",

-      "I_TAV1=I_max/FF    \n",

-      "FF=3.98184\n",

-      "I_TAV2=I_max/FF    \n",

-      "\n",

-      "\n",

-      "#RESULTS\n",

-      "print(\"(di/dt)_max=%.3f A/usec\" %(I/10**6))\n",

-      "print(\"\\n(dv/dt)_max=%.2f V/usec\" %(v/10**6))\n",

-      "print(\"\\nI_rms=%.3f A\" %I_max)\n",

-      "print(\"when conduction angle=90\")\n",

-      "print(\"I_TAV=%.3f A\" %I_TAV1)\n",

-      "print(\"when conduction angle=30\")\n",

-      "print(\"I_TAV=%.3f A\" %I_TAV2)\n",

-      "print(\"\\nvoltage rating=%.3f V\" %(2.75*V_s)) #rating is taken 2.75 times of peak working voltage unlike 2.5 to 3 times as mentioned int book."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "(di/dt)_max=21.685 A/usec\n",

-        "\n",

-        "(dv/dt)_max=216.85 V/usec\n",

-        "\n",

-        "I_rms=162.252 A\n",

-        "when conduction angle=90\n",

-        "I_TAV=73.039 A\n",

-        "when conduction angle=30\n",

-        "I_TAV=40.748 A\n",

-        "\n",

-        "voltage rating=894.490 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 10

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.19, Page No 186"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "\n",

-      "T_jm=125\n",

-      "th_jc=.15     #degC/W\n",

-      "th_cs=0.075     #degC/W\n",

-      "\n",

-      "\n",

-      "#Calculations\n",

-      "dT=54     #dT=T_s-T_a\n",

-      "P_av=120\n",

-      "th_sa=dT/P_av\n",

-      "T_a=40     #ambient temp\n",

-      "P_av=(T_jm-T_a)/(th_sa+th_jc+th_cs)\n",

-      "if (P_av-120)<1 :\n",

-      "    print(\"selection of heat sink is satisfactory\")\n",

-      "\n",

-      "dT=58     #dT=T_s-T_a\n",

-      "P_av=120\n",

-      "th_sa=dT/P_av\n",

-      "T_a=40     #ambient temp\n",

-      "P_av=(T_jm-T_a)/(th_sa+th_jc+th_cs)\n",

-      "if (P_av-120)<1 :\n",

-      "    print(\"selection of heat sink is satisfactory\")\n",

-      "\n",

-      "V_m=math.sqrt(2)*230\n",

-      "R=2\n",

-      "I_TAV=V_m/(R*math.pi)\n",

-      "P_av=90\n",

-      "th_sa=(T_jm-T_a)/P_av-(th_jc+th_cs)\n",

-      "dT=P_av*th_sa\n",

-      "print(\"for heat sink\")    \n",

-      "print(\"T_s-T_a=%.2f degC\" %dT)   \n",

-      "print(\"\\nP_av=%.0f W\" %P_av)\n",

-      "P=(V_m/2)**2/R\n",

-      "eff=P/(P+P_av)   \n",

-      "print(\"\\nckt efficiency=%.3f pu\" %eff)\n",

-      "a=60     #delay angle\n",

-      "I_TAV=(V_m/(2*math.pi*R))*(1+math.cos(math.radians(a)))\n",

-      "print(\"\\nI_TAV=%.2f A\" %I_TAV)\n",

-      "dT=46\n",

-      "T_s=dT+T_a\n",

-      "T_c=T_s+P_av*th_cs    \n",

-      "T_j=T_c+P_av*th_jc    \n",

-      "\n",

-      "#Results\n",

-      "print(\"\\ncase temp=%.2f degC\" %T_c)\n",

-      "print(\"\\njunction temp=%.2f degC\" %T_j)\n",

-      "\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for heat sink\n",

-        "T_s-T_a=-20.25 degC\n",

-        "\n",

-        "P_av=90 W\n",

-        "\n",

-        "ckt efficiency=0.993 pu\n",

-        "\n",

-        "I_TAV=38.83 A\n",

-        "\n",

-        "case temp=92.75 degC\n",

-        "\n",

-        "junction temp=106.25 degC\n"

-       ]

-      }

-     ],

-     "prompt_number": 11

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.20, Page No 187"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "T_j=125.0     #degC\n",

-      "T_s=70.0     #degC\n",

-      "th_jc=.16     #degC/W\n",

-      "th_cs=.08     #degC/W\n",

-      "\n",

-      "#Calculations\n",

-      "P_av1=(T_j-T_s)/(th_jc+th_cs)    \n",

-      "\n",

-      "T_s=60     #degC\n",

-      "P_av2=(T_j-T_s)/(th_jc+th_cs)    \n",

-      "inc=(math.sqrt(P_av2)-math.sqrt(P_av1))*100/math.sqrt(P_av1)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"Total avg power loss in thristor sink combination=%.2f W\" %P_av1)\n",

-      "print(\"Percentage inc in rating=%.2f\" %inc)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Total avg power loss in thristor sink combination=229.17 W\n",

-        "Percentage inc in rating=8.71\n"

-       ]

-      }

-     ],

-     "prompt_number": 12

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.21, Page No 197"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "\n",

-      "R=25000.0\n",

-      "I_l1=.021     #I_l=leakage current\n",

-      "I_l2=.025\n",

-      "I_l3=.018\n",

-      "I_l4=.016\n",

-      " #V1=(I-I_l1)*R\n",

-      " #V2=(I-I_l2)*R\n",

-      " #V3=(I-I_l3)*R\n",

-      " #V4=(I-I_l4)*R\n",

-      " #V=V1+V2+V3+V4\n",

-      "    \n",

-      "#Calculations\n",

-      "V=10000.0\n",

-      "I_l=I_l1+I_l2+I_l3+I_l4\n",

-      " #after solving\n",

-      "I=((V/R)+I_l)/4\n",

-      "R_c=40.0\n",

-      "V1=(I-I_l1)*R    \n",

-      "\n",

-      "#Resluts\n",

-      "print(\"voltage across SCR1=%.0f V\" %V1)\n",

-      "V2=(I-I_l2)*R    \n",

-      "print(\"\\nvoltage across SCR2=%.0f V\" %V2)\n",

-      "V3=(I-I_l3)*R    \n",

-      "print(\"\\nvoltage across SCR3=%.0f V\" %V3)\n",

-      "V4=(I-I_l4)*R    \n",

-      "print(\"\\nvoltage across SCR4=%.0f V\" %V4)\n",

-      "\n",

-      "I1=V1/R_c    \n",

-      "print(\"\\ndischarge current through SCR1=%.3f A\" %I1)\n",

-      "I2=V2/R_c   \n",

-      "print(\"\\ndischarge current through SCR2=%.3f A\" %I2)\n",

-      "I3=V3/R_c    \n",

-      "print(\"\\ndischarge current through SCR3=%.3f A\" %I3)\n",

-      "I4=V4/R_c    \n",

-      "print(\"\\ndischarge current through SCR4=%.3f A\" %I4)\n",

-      "\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "voltage across SCR1=2475 V\n",

-        "\n",

-        "voltage across SCR2=2375 V\n",

-        "\n",

-        "voltage across SCR3=2550 V\n",

-        "\n",

-        "voltage across SCR4=2600 V\n",

-        "\n",

-        "discharge current through SCR1=61.875 A\n",

-        "\n",

-        "discharge current through SCR2=59.375 A\n",

-        "\n",

-        "discharge current through SCR3=63.750 A\n",

-        "\n",

-        "discharge current through SCR4=65.000 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 13

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.22, Page No 198"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_r=1000     #rating of SCR\n",

-      "I_r=200     #rating of SCR\n",

-      "V_s=6000     #rating of String\n",

-      "I_s=1000     #rating of String\n",

-      "\n",

-      "#Calculations\n",

-      "print(\"when DRF=.1\")\n",

-      "DRF=.1\n",

-      "n_s=V_s/(V_r*(1-DRF))    \n",

-      "print(\"number of series units=%.0f\" %math.ceil(n_s))\n",

-      "n_p=I_s/(I_r*(1-DRF))    \n",

-      "print(\"\\nnumber of parrallel units=%.0f\" %math.ceil(n_p))\n",

-      "print(\"when DRF=.2\")\n",

-      "DRF=.2\n",

-      "\n",

-      "#Results\n",

-      "n_s=V_s/(V_r*(1-DRF))   \n",

-      "print(\"number of series units=%.0f\" %math.ceil(n_s))\n",

-      "n_p=I_s/(I_r*(1-DRF))    \n",

-      "print(\"\\nnumber of parrallel units=%.0f\" %math.ceil(n_p))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "when DRF=.1\n",

-        "number of series units=7\n",

-        "\n",

-        "number of parrallel units=6\n",

-        "when DRF=.2\n",

-        "number of series units=8\n",

-        "\n",

-        "number of parrallel units=7\n"

-       ]

-      }

-     ],

-     "prompt_number": 14

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.23, Page No 198"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V1=1.6     #on state voltage drop of SCR1\n",

-      "V2=1.2     #on state voltage drop of SCR2\n",

-      "I1=250.0     #current rating of SCR1\n",

-      "I2=350.0     #current rating of SCR2\n",

-      "\n",

-      "#Calculations\n",

-      "R1=V1/I1\n",

-      "R2=V2/I2\n",

-      "I=600.0     #current to be shared\n",

-      " #for SCR1 %     I*(R1+R)/(total resistance)=k*I1                    (1)\n",

-      " #for SCR2 %     I*(R2+R)/(total resistance)=k*I2                    (2)\n",

-      " #(1)/(2)\n",

-      "R=(R2*I2-R1*I1)/(I1-I2)\n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"RSequired value of resistance=%.3f ohm\" %R)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "RSequired value of resistance=0.004 ohm\n"

-       ]

-      }

-     ],

-     "prompt_number": 15

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.25, Page No 223"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "f=2000.0     #Hz\n",

-      "C=0.04*10**-6\n",

-      "n=.72\n",

-      "\n",

-      "#Calculations\n",

-      "R=1/(f*C*math.log(1/(1-n)))    \n",

-      "V_p=18\n",

-      "V_BB=V_p/n\n",

-      "R2=10**4/(n*V_BB)    \n",

-      "I=4.2*10**-3     #leakage current\n",

-      "R_BB=5000\n",

-      "R1=(V_BB/I)-R2-R_BB\n",

-      "\n",

-      "#Results\n",

-      "print(\"R=%.2f kilo-ohm\" %(R/1000))\n",

-      "print(\"\\nR2=%.2f ohm\" %R2)\n",

-      "print(\"\\nR1=%.0f ohm\" %R1)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "R=9.82 kilo-ohm\n",

-        "\n",

-        "R2=555.56 ohm\n",

-        "\n",

-        "R1=397 ohm\n"

-       ]

-      }

-     ],

-     "prompt_number": 16

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.26, Page No 223"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "\n",

-      "V_p=18.0\n",

-      "n=.72\n",

-      "V_BB=V_p/n\n",

-      "I_p=.6*10**-3\n",

-      "I_v=2.5*10**-3\n",

-      "V_v=1\n",

-      "\n",

-      "#Calculations\n",

-      "R_max=V_BB*(1-n)/I_p    \n",

-      "print(\"R_max=%.2f kilo-ohm\" %(R_max/1000))\n",

-      "R_min=(V_BB-V_v)/I_v    \n",

-      "print(\"\\nR_min=%.2f kilo-ohm\" %(R_min/1000))\n",

-      "\n",

-      "C=.04*10**-6\n",

-      "f_min=1/(R_max*C*math.log(1/(1-n)))    \n",

-      "print(\"\\nf_min=%.3f kHz\" %(f_min/1000))\n",

-      "f_max=1/(R_min*C*math.log(1/(1-n)))    \n",

-      "print(\"\\nf_max=%.2f kHz\" %(f_max/1000))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "R_max=11.67 kilo-ohm\n",

-        "\n",

-        "R_min=9.60 kilo-ohm\n",

-        "\n",

-        "f_min=1.683 kHz\n",

-        "\n",

-        "f_max=2.05 kHz\n"

-       ]

-      }

-     ],

-     "prompt_number": 17

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Power_Electronics/Chapter4_2.ipynb b/_Power_Electronics/Chapter4_2.ipynb
deleted file mode 100755
index 22311574..00000000
--- a/_Power_Electronics/Chapter4_2.ipynb
+++ /dev/null
@@ -1,946 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 04 : Thyristors"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.3, Page No 149"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "P=.5    #P=V_g*I_g\n",

-      "s=130    #s=V_g/I_g\n",

-      "\n",

-      "#Calculations\n",

-      "I_g=math.sqrt(P/s)\n",

-      "V_g=s*I_g\n",

-      "E=15\n",

-      "R_s=(E-V_g)/I_g    \n",

-      "\n",

-      "#Results\n",

-      "print(\"Gate source resistance=%.2f ohm\" %R_s)\n",

-      "#Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Gate source resistance=111.87 ohm\n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.4, Page No 149"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "\n",

-      "R_s=120     #slope of load line is -120V/A. This gives gate source resistance\n",

-      "print(\"gate source resistance=%.0f ohm\" %R_s)\n",

-      "\n",

-      "P=.4     #P=V_g*I_g\n",

-      "E_s=15\n",

-      "\n",

-      "#Calculations\n",

-      " #E_s=I_g*R_s+V_g %    after solving this\n",

-      " #120*I_g**2-15*I_g+0.4=0    so\n",

-      "a=120   \n",

-      "b=-15\n",

-      "c=0.4\n",

-      "D=math.sqrt((b**2)-4*a*c)\n",

-      "I_g=(-b+D)/(2*a)   \n",

-      "V_g=P/I_g\n",

-      "\n",

-      "#Results\n",

-      "print(\"\\ntrigger current=%.2f mA\" %(I_g*10**3))    \n",

-      "print(\"\\nthen trigger voltage=%.3f V\" %V_g)\n",

-      "I_g=(-b-D)/(2*a)   \n",

-      "V_g=P/I_g\n",

-      "print(\"\\ntrigger current=%.2f mA\" %(I_g*10**3))    \n",

-      "print(\"\\nthen trigger voltage=%.2f V\" %V_g)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "gate source resistance=120 ohm\n",

-        "\n",

-        "trigger current=86.44 mA\n",

-        "\n",

-        "then trigger voltage=4.628 V\n",

-        "\n",

-        "trigger current=38.56 mA\n",

-        "\n",

-        "then trigger voltage=10.37 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 2

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.5 Page No 150"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "\n",

-      "#V_g=1+10*I_g\n",

-      "P_gm=5     #P_gm=V_g*I_g\n",

-      "#after solving % eqn becomes 10*I_g**2+I_g-5=0\n",

-      "a=10.0    \n",

-      "b=1.0    \n",

-      "c=-5\n",

-      "\n",

-      "#Calculations\n",

-      "I_g=(-b+math.sqrt(b**2-4*a*c))/(2*a)\n",

-      "E_s=15\n",

-      "#using E_s=R_s*I_g+V_g\n",

-      "R_s=(E_s-1)/I_g-10   \n",

-      "P_gav=.3     #W\n",

-      "T=20*10**-6\n",

-      "f=P_gav/(P_gm*T)\n",

-      "dl=f*T\n",

-      "\n",

-      "#Results\n",

-      "print(\"Reistance=%.3f ohm\" %R_s)\n",

-      "print(\"Triggering freq=%.0f kHz\" %(f/1000))\n",

-      "print(\"Tduty cycle=%.2f\" %dl)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Reistance=11.248 ohm\n",

-        "Triggering freq=3 kHz\n",

-        "Tduty cycle=0.06\n"

-       ]

-      }

-     ],

-     "prompt_number": 3

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.6, Page No 151"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "I=.1\n",

-      "E=200.0\n",

-      "L=0.2\n",

-      "\n",

-      "#Calculations\n",

-      "t=I*L/E   \n",

-      "R=20.0\n",

-      "t1=(-L/R)*math.log(1-(R*I/E))    \n",

-      "L=2.0\n",

-      "t2=(-L/R)*math.log(1-(R*I/E))   \n",

-      "\n",

-      "#Results\n",

-      "print(\"in case load consists of (a)L=.2H\")\n",

-      "print(\"min gate pulse width=%.0f us\" %(t*10**6))\n",

-      "print(\"(b)R=20ohm in series with L=.2H\")\n",

-      "print(\"min gate pulse width=%.3f us\" %(t1*10**6))\n",

-      "print(\"(c)R=20ohm in series with L=2H\")\n",

-      "print(\"min gate pulse width=%.2f us\" %(t2*10**6))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "in case load consists of (a)L=.2H\n",

-        "min gate pulse width=100 us\n",

-        "(b)R=20ohm in series with L=.2H\n",

-        "min gate pulse width=100.503 us\n",

-        "(c)R=20ohm in series with L=2H\n",

-        "min gate pulse width=1005.03 us\n"

-       ]

-      }

-     ],

-     "prompt_number": 4

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.9 Page No 163"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "\n",

-      "def theta(th):\n",

-      "    I_m=1     #supposition\n",

-      "    I_av=(I_m/(2*math.pi))*(1+math.cos(math.radians(th)))\n",

-      "    I_rms=math.sqrt((I_m/(2*math.pi))*((180-th)*math.pi/360+.25*math.sin(math.radians(2*th))))\n",

-      "    FF=I_rms/I_av\n",

-      "    I_rms=35\n",

-      "    I_TAV=I_rms/FF\n",

-      "    return I_TAV\n",

-      "\n",

-      "#Calculations\n",

-      "print(\"when conduction angle=180\")\n",

-      "th=0\n",

-      "I_TAV=theta(th)\n",

-      "print(\"avg on current rating=%.3f A\" %I_TAV)\n",

-      "print(\"when conduction angle=90\")\n",

-      "th=90\n",

-      "I_TAV=theta(th)\n",

-      "\n",

-      "#Results\n",

-      "print(\"avg on current rating=%.3f A\" %I_TAV)\n",

-      "print(\"when conduction angle=30\")\n",

-      "th=150\n",

-      "I_TAV=theta(th)\n",

-      "print(\"avg on current rating=%.3f A\" %I_TAV)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "when conduction angle=180\n",

-        "avg on current rating=22.282 A\n",

-        "when conduction angle=90\n",

-        "avg on current rating=15.756 A\n",

-        "when conduction angle=30\n",

-        "avg on current rating=8.790 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 5

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.10, Page No 164"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "\n",

-      "def theta(th):\n",

-      "    n=360.0/th\n",

-      "    I=1.0     #supposition\n",

-      "    I_av=I/n\n",

-      "    I_rms=I/math.sqrt(n)\n",

-      "    FF=I_rms/I_av\n",

-      "    I_rms=35\n",

-      "    I_TAV=I_rms/FF\n",

-      "    return I_TAV\n",

-      "\n",

-      "#Calculations\n",

-      "th=180.0\n",

-      "I_TAV1=theta(th)\n",

-      "th=90.0\n",

-      "I_TAV2=theta(th)\n",

-      "th=30.0\n",

-      "I_TAV3=theta(th)\n",

-      "\n",

-      "#Results\n",

-      "print(\"when conduction angle=180\")\n",

-      "print(\"avg on current rating=%.3f A\" %I_TAV)\n",

-      "print(\"when conduction angle=90\")\n",

-      "print(\"avg on current rating=%.1f A\" %I_TAV2)\n",

-      "print(\"when conduction angle=30\")\n",

-      "print(\"avg on current rating=%.4f A\" %I_TAV3)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "when conduction angle=180\n",

-        "avg on current rating=8.790 A\n",

-        "when conduction angle=90\n",

-        "avg on current rating=17.5 A\n",

-        "when conduction angle=30\n",

-        "avg on current rating=10.1036 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 6

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.11 Page No 165"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math \n",

-      "\n",

-      "#initialisation of variables\n",

-      "f=50.0     #Hz\n",

-      "\n",

-      "#Calculations\n",

-      "I_sb=3000.0\n",

-      "t=1/(4*f)\n",

-      "T=1/(2*f)\n",

-      "I=math.sqrt(I_sb**2*t/T)    \n",

-      "r=(I_sb/math.sqrt(2))**2*T   \n",

-      "\n",

-      "#Results\n",

-      "print(\"surge current rating=%.2f A\" %I)\n",

-      "print(\"\\nI**2*t rating=%.0f A^2.s\" %r)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "surge current rating=2121.32 A\n",

-        "\n",

-        "I**2*t rating=45000 A^2.s\n"

-       ]

-      }

-     ],

-     "prompt_number": 7

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.12 Page No 165"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "\n",

-      "V_s=300.0 #V\n",

-      "R=60.0 #ohm\n",

-      "L=2.0 #H\n",

-      "\n",

-      "#Calculations\n",

-      "t=40*10**-6 #s\n",

-      "i_T=(V_s/R)*(1-math.exp(-R*t/L))\n",

-      "i=.036 #A\n",

-      "R1=V_s/(i-i_T)\n",

-      "\n",

-      "#Results\n",

-      "print(\"maximum value of remedial parameter=%.3f kilo-ohm\" %(R1/1000))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "maximum value of remedial parameter=9.999 kilo-ohm\n"

-       ]

-      }

-     ],

-     "prompt_number": 8

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.16 Page No 172"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "V_p=230.0*math.sqrt(2)\n",

-      "\n",

-      "#Calculations\n",

-      "R=1+((1)**-1+(10)**-1)**-1\n",

-      "A=V_p/R\n",

-      "s=1     #s\n",

-      "t_c=20*A**-2*s\n",

-      "\n",

-      "#Results\n",

-      "print(\"fault clearance time=%.4f ms\" %(t_c*10**3))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "fault clearance time=0.6890 ms\n"

-       ]

-      }

-     ],

-     "prompt_number": 9

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.17, Page No 176"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "\n",

-      "V_s=math.sqrt(2)*230     #V\n",

-      "L=15*10**-6     #H\n",

-      "I=V_s/L     #I=(di/dt)_max\n",

-      "R_s=10   #ohm\n",

-      "v=I*R_s     #v=(dv/dt)_max\n",

-      "\n",

-      "#Calculations\n",

-      "f=50     #Hz\n",

-      "X_L=L*2*math.pi*f\n",

-      "R=2\n",

-      "I_max=V_s/(R+X_L)    \n",

-      "FF=math.pi/math.sqrt(2)\n",

-      "I_TAV1=I_max/FF    \n",

-      "FF=3.98184\n",

-      "I_TAV2=I_max/FF    \n",

-      "\n",

-      "\n",

-      "#RESULTS\n",

-      "print(\"(di/dt)_max=%.3f A/usec\" %(I/10**6))\n",

-      "print(\"\\n(dv/dt)_max=%.2f V/usec\" %(v/10**6))\n",

-      "print(\"\\nI_rms=%.3f A\" %I_max)\n",

-      "print(\"when conduction angle=90\")\n",

-      "print(\"I_TAV=%.3f A\" %I_TAV1)\n",

-      "print(\"when conduction angle=30\")\n",

-      "print(\"I_TAV=%.3f A\" %I_TAV2)\n",

-      "print(\"\\nvoltage rating=%.3f V\" %(2.75*V_s)) #rating is taken 2.75 times of peak working voltage unlike 2.5 to 3 times as mentioned int book."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "(di/dt)_max=21.685 A/usec\n",

-        "\n",

-        "(dv/dt)_max=216.85 V/usec\n",

-        "\n",

-        "I_rms=162.252 A\n",

-        "when conduction angle=90\n",

-        "I_TAV=73.039 A\n",

-        "when conduction angle=30\n",

-        "I_TAV=40.748 A\n",

-        "\n",

-        "voltage rating=894.490 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 10

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.19, Page No 186"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "\n",

-      "T_jm=125\n",

-      "th_jc=.15     #degC/W\n",

-      "th_cs=0.075     #degC/W\n",

-      "\n",

-      "\n",

-      "#Calculations\n",

-      "dT=54     #dT=T_s-T_a\n",

-      "P_av=120\n",

-      "th_sa=dT/P_av\n",

-      "T_a=40     #ambient temp\n",

-      "P_av=(T_jm-T_a)/(th_sa+th_jc+th_cs)\n",

-      "if (P_av-120)<1 :\n",

-      "    print(\"selection of heat sink is satisfactory\")\n",

-      "\n",

-      "dT=58     #dT=T_s-T_a\n",

-      "P_av=120\n",

-      "th_sa=dT/P_av\n",

-      "T_a=40     #ambient temp\n",

-      "P_av=(T_jm-T_a)/(th_sa+th_jc+th_cs)\n",

-      "if (P_av-120)<1 :\n",

-      "    print(\"selection of heat sink is satisfactory\")\n",

-      "\n",

-      "V_m=math.sqrt(2)*230\n",

-      "R=2\n",

-      "I_TAV=V_m/(R*math.pi)\n",

-      "P_av=90\n",

-      "th_sa=(T_jm-T_a)/P_av-(th_jc+th_cs)\n",

-      "dT=P_av*th_sa\n",

-      "print(\"for heat sink\")    \n",

-      "print(\"T_s-T_a=%.2f degC\" %dT)   \n",

-      "print(\"\\nP_av=%.0f W\" %P_av)\n",

-      "P=(V_m/2)**2/R\n",

-      "eff=P/(P+P_av)   \n",

-      "print(\"\\nckt efficiency=%.3f pu\" %eff)\n",

-      "a=60     #delay angle\n",

-      "I_TAV=(V_m/(2*math.pi*R))*(1+math.cos(math.radians(a)))\n",

-      "print(\"\\nI_TAV=%.2f A\" %I_TAV)\n",

-      "dT=46\n",

-      "T_s=dT+T_a\n",

-      "T_c=T_s+P_av*th_cs    \n",

-      "T_j=T_c+P_av*th_jc    \n",

-      "\n",

-      "#Results\n",

-      "print(\"\\ncase temp=%.2f degC\" %T_c)\n",

-      "print(\"\\njunction temp=%.2f degC\" %T_j)\n",

-      "\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for heat sink\n",

-        "T_s-T_a=-20.25 degC\n",

-        "\n",

-        "P_av=90 W\n",

-        "\n",

-        "ckt efficiency=0.993 pu\n",

-        "\n",

-        "I_TAV=38.83 A\n",

-        "\n",

-        "case temp=92.75 degC\n",

-        "\n",

-        "junction temp=106.25 degC\n"

-       ]

-      }

-     ],

-     "prompt_number": 11

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.20, Page No 187"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "T_j=125.0     #degC\n",

-      "T_s=70.0     #degC\n",

-      "th_jc=.16     #degC/W\n",

-      "th_cs=.08     #degC/W\n",

-      "\n",

-      "#Calculations\n",

-      "P_av1=(T_j-T_s)/(th_jc+th_cs)    \n",

-      "\n",

-      "T_s=60     #degC\n",

-      "P_av2=(T_j-T_s)/(th_jc+th_cs)    \n",

-      "inc=(math.sqrt(P_av2)-math.sqrt(P_av1))*100/math.sqrt(P_av1)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"Total avg power loss in thristor sink combination=%.2f W\" %P_av1)\n",

-      "print(\"Percentage inc in rating=%.2f\" %inc)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Total avg power loss in thristor sink combination=229.17 W\n",

-        "Percentage inc in rating=8.71\n"

-       ]

-      }

-     ],

-     "prompt_number": 12

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.21, Page No 197"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "\n",

-      "R=25000.0\n",

-      "I_l1=.021     #I_l=leakage current\n",

-      "I_l2=.025\n",

-      "I_l3=.018\n",

-      "I_l4=.016\n",

-      " #V1=(I-I_l1)*R\n",

-      " #V2=(I-I_l2)*R\n",

-      " #V3=(I-I_l3)*R\n",

-      " #V4=(I-I_l4)*R\n",

-      " #V=V1+V2+V3+V4\n",

-      "    \n",

-      "#Calculations\n",

-      "V=10000.0\n",

-      "I_l=I_l1+I_l2+I_l3+I_l4\n",

-      " #after solving\n",

-      "I=((V/R)+I_l)/4\n",

-      "R_c=40.0\n",

-      "V1=(I-I_l1)*R    \n",

-      "\n",

-      "#Resluts\n",

-      "print(\"voltage across SCR1=%.0f V\" %V1)\n",

-      "V2=(I-I_l2)*R    \n",

-      "print(\"\\nvoltage across SCR2=%.0f V\" %V2)\n",

-      "V3=(I-I_l3)*R    \n",

-      "print(\"\\nvoltage across SCR3=%.0f V\" %V3)\n",

-      "V4=(I-I_l4)*R    \n",

-      "print(\"\\nvoltage across SCR4=%.0f V\" %V4)\n",

-      "\n",

-      "I1=V1/R_c    \n",

-      "print(\"\\ndischarge current through SCR1=%.3f A\" %I1)\n",

-      "I2=V2/R_c   \n",

-      "print(\"\\ndischarge current through SCR2=%.3f A\" %I2)\n",

-      "I3=V3/R_c    \n",

-      "print(\"\\ndischarge current through SCR3=%.3f A\" %I3)\n",

-      "I4=V4/R_c    \n",

-      "print(\"\\ndischarge current through SCR4=%.3f A\" %I4)\n",

-      "\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "voltage across SCR1=2475 V\n",

-        "\n",

-        "voltage across SCR2=2375 V\n",

-        "\n",

-        "voltage across SCR3=2550 V\n",

-        "\n",

-        "voltage across SCR4=2600 V\n",

-        "\n",

-        "discharge current through SCR1=61.875 A\n",

-        "\n",

-        "discharge current through SCR2=59.375 A\n",

-        "\n",

-        "discharge current through SCR3=63.750 A\n",

-        "\n",

-        "discharge current through SCR4=65.000 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 13

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.22, Page No 198"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_r=1000     #rating of SCR\n",

-      "I_r=200     #rating of SCR\n",

-      "V_s=6000     #rating of String\n",

-      "I_s=1000     #rating of String\n",

-      "\n",

-      "#Calculations\n",

-      "print(\"when DRF=.1\")\n",

-      "DRF=.1\n",

-      "n_s=V_s/(V_r*(1-DRF))    \n",

-      "print(\"number of series units=%.0f\" %math.ceil(n_s))\n",

-      "n_p=I_s/(I_r*(1-DRF))    \n",

-      "print(\"\\nnumber of parrallel units=%.0f\" %math.ceil(n_p))\n",

-      "print(\"when DRF=.2\")\n",

-      "DRF=.2\n",

-      "\n",

-      "#Results\n",

-      "n_s=V_s/(V_r*(1-DRF))   \n",

-      "print(\"number of series units=%.0f\" %math.ceil(n_s))\n",

-      "n_p=I_s/(I_r*(1-DRF))    \n",

-      "print(\"\\nnumber of parrallel units=%.0f\" %math.ceil(n_p))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "when DRF=.1\n",

-        "number of series units=7\n",

-        "\n",

-        "number of parrallel units=6\n",

-        "when DRF=.2\n",

-        "number of series units=8\n",

-        "\n",

-        "number of parrallel units=7\n"

-       ]

-      }

-     ],

-     "prompt_number": 14

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.23, Page No 198"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V1=1.6     #on state voltage drop of SCR1\n",

-      "V2=1.2     #on state voltage drop of SCR2\n",

-      "I1=250.0     #current rating of SCR1\n",

-      "I2=350.0     #current rating of SCR2\n",

-      "\n",

-      "#Calculations\n",

-      "R1=V1/I1\n",

-      "R2=V2/I2\n",

-      "I=600.0     #current to be shared\n",

-      " #for SCR1 %     I*(R1+R)/(total resistance)=k*I1                    (1)\n",

-      " #for SCR2 %     I*(R2+R)/(total resistance)=k*I2                    (2)\n",

-      " #(1)/(2)\n",

-      "R=(R2*I2-R1*I1)/(I1-I2)\n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"RSequired value of resistance=%.3f ohm\" %R)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "RSequired value of resistance=0.004 ohm\n"

-       ]

-      }

-     ],

-     "prompt_number": 15

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.25, Page No 223"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "f=2000.0     #Hz\n",

-      "C=0.04*10**-6\n",

-      "n=.72\n",

-      "\n",

-      "#Calculations\n",

-      "R=1/(f*C*math.log(1/(1-n)))    \n",

-      "V_p=18\n",

-      "V_BB=V_p/n\n",

-      "R2=10**4/(n*V_BB)    \n",

-      "I=4.2*10**-3     #leakage current\n",

-      "R_BB=5000\n",

-      "R1=(V_BB/I)-R2-R_BB\n",

-      "\n",

-      "#Results\n",

-      "print(\"R=%.2f kilo-ohm\" %(R/1000))\n",

-      "print(\"\\nR2=%.2f ohm\" %R2)\n",

-      "print(\"\\nR1=%.0f ohm\" %R1)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "R=9.82 kilo-ohm\n",

-        "\n",

-        "R2=555.56 ohm\n",

-        "\n",

-        "R1=397 ohm\n"

-       ]

-      }

-     ],

-     "prompt_number": 16

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.26, Page No 223"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "\n",

-      "V_p=18.0\n",

-      "n=.72\n",

-      "V_BB=V_p/n\n",

-      "I_p=.6*10**-3\n",

-      "I_v=2.5*10**-3\n",

-      "V_v=1\n",

-      "\n",

-      "#Calculations\n",

-      "R_max=V_BB*(1-n)/I_p    \n",

-      "print(\"R_max=%.2f kilo-ohm\" %(R_max/1000))\n",

-      "R_min=(V_BB-V_v)/I_v    \n",

-      "print(\"\\nR_min=%.2f kilo-ohm\" %(R_min/1000))\n",

-      "\n",

-      "C=.04*10**-6\n",

-      "f_min=1/(R_max*C*math.log(1/(1-n)))    \n",

-      "print(\"\\nf_min=%.3f kHz\" %(f_min/1000))\n",

-      "f_max=1/(R_min*C*math.log(1/(1-n)))    \n",

-      "print(\"\\nf_max=%.2f kHz\" %(f_max/1000))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "R_max=11.67 kilo-ohm\n",

-        "\n",

-        "R_min=9.60 kilo-ohm\n",

-        "\n",

-        "f_min=1.683 kHz\n",

-        "\n",

-        "f_max=2.05 kHz\n"

-       ]

-      }

-     ],

-     "prompt_number": 17

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Power_Electronics/Chapter4_3.ipynb b/_Power_Electronics/Chapter4_3.ipynb
deleted file mode 100755
index 22311574..00000000
--- a/_Power_Electronics/Chapter4_3.ipynb
+++ /dev/null
@@ -1,946 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 04 : Thyristors"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.3, Page No 149"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "P=.5    #P=V_g*I_g\n",

-      "s=130    #s=V_g/I_g\n",

-      "\n",

-      "#Calculations\n",

-      "I_g=math.sqrt(P/s)\n",

-      "V_g=s*I_g\n",

-      "E=15\n",

-      "R_s=(E-V_g)/I_g    \n",

-      "\n",

-      "#Results\n",

-      "print(\"Gate source resistance=%.2f ohm\" %R_s)\n",

-      "#Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Gate source resistance=111.87 ohm\n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.4, Page No 149"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "\n",

-      "R_s=120     #slope of load line is -120V/A. This gives gate source resistance\n",

-      "print(\"gate source resistance=%.0f ohm\" %R_s)\n",

-      "\n",

-      "P=.4     #P=V_g*I_g\n",

-      "E_s=15\n",

-      "\n",

-      "#Calculations\n",

-      " #E_s=I_g*R_s+V_g %    after solving this\n",

-      " #120*I_g**2-15*I_g+0.4=0    so\n",

-      "a=120   \n",

-      "b=-15\n",

-      "c=0.4\n",

-      "D=math.sqrt((b**2)-4*a*c)\n",

-      "I_g=(-b+D)/(2*a)   \n",

-      "V_g=P/I_g\n",

-      "\n",

-      "#Results\n",

-      "print(\"\\ntrigger current=%.2f mA\" %(I_g*10**3))    \n",

-      "print(\"\\nthen trigger voltage=%.3f V\" %V_g)\n",

-      "I_g=(-b-D)/(2*a)   \n",

-      "V_g=P/I_g\n",

-      "print(\"\\ntrigger current=%.2f mA\" %(I_g*10**3))    \n",

-      "print(\"\\nthen trigger voltage=%.2f V\" %V_g)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "gate source resistance=120 ohm\n",

-        "\n",

-        "trigger current=86.44 mA\n",

-        "\n",

-        "then trigger voltage=4.628 V\n",

-        "\n",

-        "trigger current=38.56 mA\n",

-        "\n",

-        "then trigger voltage=10.37 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 2

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.5 Page No 150"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "\n",

-      "#V_g=1+10*I_g\n",

-      "P_gm=5     #P_gm=V_g*I_g\n",

-      "#after solving % eqn becomes 10*I_g**2+I_g-5=0\n",

-      "a=10.0    \n",

-      "b=1.0    \n",

-      "c=-5\n",

-      "\n",

-      "#Calculations\n",

-      "I_g=(-b+math.sqrt(b**2-4*a*c))/(2*a)\n",

-      "E_s=15\n",

-      "#using E_s=R_s*I_g+V_g\n",

-      "R_s=(E_s-1)/I_g-10   \n",

-      "P_gav=.3     #W\n",

-      "T=20*10**-6\n",

-      "f=P_gav/(P_gm*T)\n",

-      "dl=f*T\n",

-      "\n",

-      "#Results\n",

-      "print(\"Reistance=%.3f ohm\" %R_s)\n",

-      "print(\"Triggering freq=%.0f kHz\" %(f/1000))\n",

-      "print(\"Tduty cycle=%.2f\" %dl)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Reistance=11.248 ohm\n",

-        "Triggering freq=3 kHz\n",

-        "Tduty cycle=0.06\n"

-       ]

-      }

-     ],

-     "prompt_number": 3

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.6, Page No 151"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "I=.1\n",

-      "E=200.0\n",

-      "L=0.2\n",

-      "\n",

-      "#Calculations\n",

-      "t=I*L/E   \n",

-      "R=20.0\n",

-      "t1=(-L/R)*math.log(1-(R*I/E))    \n",

-      "L=2.0\n",

-      "t2=(-L/R)*math.log(1-(R*I/E))   \n",

-      "\n",

-      "#Results\n",

-      "print(\"in case load consists of (a)L=.2H\")\n",

-      "print(\"min gate pulse width=%.0f us\" %(t*10**6))\n",

-      "print(\"(b)R=20ohm in series with L=.2H\")\n",

-      "print(\"min gate pulse width=%.3f us\" %(t1*10**6))\n",

-      "print(\"(c)R=20ohm in series with L=2H\")\n",

-      "print(\"min gate pulse width=%.2f us\" %(t2*10**6))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "in case load consists of (a)L=.2H\n",

-        "min gate pulse width=100 us\n",

-        "(b)R=20ohm in series with L=.2H\n",

-        "min gate pulse width=100.503 us\n",

-        "(c)R=20ohm in series with L=2H\n",

-        "min gate pulse width=1005.03 us\n"

-       ]

-      }

-     ],

-     "prompt_number": 4

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.9 Page No 163"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "\n",

-      "def theta(th):\n",

-      "    I_m=1     #supposition\n",

-      "    I_av=(I_m/(2*math.pi))*(1+math.cos(math.radians(th)))\n",

-      "    I_rms=math.sqrt((I_m/(2*math.pi))*((180-th)*math.pi/360+.25*math.sin(math.radians(2*th))))\n",

-      "    FF=I_rms/I_av\n",

-      "    I_rms=35\n",

-      "    I_TAV=I_rms/FF\n",

-      "    return I_TAV\n",

-      "\n",

-      "#Calculations\n",

-      "print(\"when conduction angle=180\")\n",

-      "th=0\n",

-      "I_TAV=theta(th)\n",

-      "print(\"avg on current rating=%.3f A\" %I_TAV)\n",

-      "print(\"when conduction angle=90\")\n",

-      "th=90\n",

-      "I_TAV=theta(th)\n",

-      "\n",

-      "#Results\n",

-      "print(\"avg on current rating=%.3f A\" %I_TAV)\n",

-      "print(\"when conduction angle=30\")\n",

-      "th=150\n",

-      "I_TAV=theta(th)\n",

-      "print(\"avg on current rating=%.3f A\" %I_TAV)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "when conduction angle=180\n",

-        "avg on current rating=22.282 A\n",

-        "when conduction angle=90\n",

-        "avg on current rating=15.756 A\n",

-        "when conduction angle=30\n",

-        "avg on current rating=8.790 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 5

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.10, Page No 164"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "\n",

-      "def theta(th):\n",

-      "    n=360.0/th\n",

-      "    I=1.0     #supposition\n",

-      "    I_av=I/n\n",

-      "    I_rms=I/math.sqrt(n)\n",

-      "    FF=I_rms/I_av\n",

-      "    I_rms=35\n",

-      "    I_TAV=I_rms/FF\n",

-      "    return I_TAV\n",

-      "\n",

-      "#Calculations\n",

-      "th=180.0\n",

-      "I_TAV1=theta(th)\n",

-      "th=90.0\n",

-      "I_TAV2=theta(th)\n",

-      "th=30.0\n",

-      "I_TAV3=theta(th)\n",

-      "\n",

-      "#Results\n",

-      "print(\"when conduction angle=180\")\n",

-      "print(\"avg on current rating=%.3f A\" %I_TAV)\n",

-      "print(\"when conduction angle=90\")\n",

-      "print(\"avg on current rating=%.1f A\" %I_TAV2)\n",

-      "print(\"when conduction angle=30\")\n",

-      "print(\"avg on current rating=%.4f A\" %I_TAV3)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "when conduction angle=180\n",

-        "avg on current rating=8.790 A\n",

-        "when conduction angle=90\n",

-        "avg on current rating=17.5 A\n",

-        "when conduction angle=30\n",

-        "avg on current rating=10.1036 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 6

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.11 Page No 165"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math \n",

-      "\n",

-      "#initialisation of variables\n",

-      "f=50.0     #Hz\n",

-      "\n",

-      "#Calculations\n",

-      "I_sb=3000.0\n",

-      "t=1/(4*f)\n",

-      "T=1/(2*f)\n",

-      "I=math.sqrt(I_sb**2*t/T)    \n",

-      "r=(I_sb/math.sqrt(2))**2*T   \n",

-      "\n",

-      "#Results\n",

-      "print(\"surge current rating=%.2f A\" %I)\n",

-      "print(\"\\nI**2*t rating=%.0f A^2.s\" %r)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "surge current rating=2121.32 A\n",

-        "\n",

-        "I**2*t rating=45000 A^2.s\n"

-       ]

-      }

-     ],

-     "prompt_number": 7

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.12 Page No 165"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "\n",

-      "V_s=300.0 #V\n",

-      "R=60.0 #ohm\n",

-      "L=2.0 #H\n",

-      "\n",

-      "#Calculations\n",

-      "t=40*10**-6 #s\n",

-      "i_T=(V_s/R)*(1-math.exp(-R*t/L))\n",

-      "i=.036 #A\n",

-      "R1=V_s/(i-i_T)\n",

-      "\n",

-      "#Results\n",

-      "print(\"maximum value of remedial parameter=%.3f kilo-ohm\" %(R1/1000))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "maximum value of remedial parameter=9.999 kilo-ohm\n"

-       ]

-      }

-     ],

-     "prompt_number": 8

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.16 Page No 172"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "V_p=230.0*math.sqrt(2)\n",

-      "\n",

-      "#Calculations\n",

-      "R=1+((1)**-1+(10)**-1)**-1\n",

-      "A=V_p/R\n",

-      "s=1     #s\n",

-      "t_c=20*A**-2*s\n",

-      "\n",

-      "#Results\n",

-      "print(\"fault clearance time=%.4f ms\" %(t_c*10**3))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "fault clearance time=0.6890 ms\n"

-       ]

-      }

-     ],

-     "prompt_number": 9

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.17, Page No 176"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "\n",

-      "V_s=math.sqrt(2)*230     #V\n",

-      "L=15*10**-6     #H\n",

-      "I=V_s/L     #I=(di/dt)_max\n",

-      "R_s=10   #ohm\n",

-      "v=I*R_s     #v=(dv/dt)_max\n",

-      "\n",

-      "#Calculations\n",

-      "f=50     #Hz\n",

-      "X_L=L*2*math.pi*f\n",

-      "R=2\n",

-      "I_max=V_s/(R+X_L)    \n",

-      "FF=math.pi/math.sqrt(2)\n",

-      "I_TAV1=I_max/FF    \n",

-      "FF=3.98184\n",

-      "I_TAV2=I_max/FF    \n",

-      "\n",

-      "\n",

-      "#RESULTS\n",

-      "print(\"(di/dt)_max=%.3f A/usec\" %(I/10**6))\n",

-      "print(\"\\n(dv/dt)_max=%.2f V/usec\" %(v/10**6))\n",

-      "print(\"\\nI_rms=%.3f A\" %I_max)\n",

-      "print(\"when conduction angle=90\")\n",

-      "print(\"I_TAV=%.3f A\" %I_TAV1)\n",

-      "print(\"when conduction angle=30\")\n",

-      "print(\"I_TAV=%.3f A\" %I_TAV2)\n",

-      "print(\"\\nvoltage rating=%.3f V\" %(2.75*V_s)) #rating is taken 2.75 times of peak working voltage unlike 2.5 to 3 times as mentioned int book."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "(di/dt)_max=21.685 A/usec\n",

-        "\n",

-        "(dv/dt)_max=216.85 V/usec\n",

-        "\n",

-        "I_rms=162.252 A\n",

-        "when conduction angle=90\n",

-        "I_TAV=73.039 A\n",

-        "when conduction angle=30\n",

-        "I_TAV=40.748 A\n",

-        "\n",

-        "voltage rating=894.490 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 10

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.19, Page No 186"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "\n",

-      "T_jm=125\n",

-      "th_jc=.15     #degC/W\n",

-      "th_cs=0.075     #degC/W\n",

-      "\n",

-      "\n",

-      "#Calculations\n",

-      "dT=54     #dT=T_s-T_a\n",

-      "P_av=120\n",

-      "th_sa=dT/P_av\n",

-      "T_a=40     #ambient temp\n",

-      "P_av=(T_jm-T_a)/(th_sa+th_jc+th_cs)\n",

-      "if (P_av-120)<1 :\n",

-      "    print(\"selection of heat sink is satisfactory\")\n",

-      "\n",

-      "dT=58     #dT=T_s-T_a\n",

-      "P_av=120\n",

-      "th_sa=dT/P_av\n",

-      "T_a=40     #ambient temp\n",

-      "P_av=(T_jm-T_a)/(th_sa+th_jc+th_cs)\n",

-      "if (P_av-120)<1 :\n",

-      "    print(\"selection of heat sink is satisfactory\")\n",

-      "\n",

-      "V_m=math.sqrt(2)*230\n",

-      "R=2\n",

-      "I_TAV=V_m/(R*math.pi)\n",

-      "P_av=90\n",

-      "th_sa=(T_jm-T_a)/P_av-(th_jc+th_cs)\n",

-      "dT=P_av*th_sa\n",

-      "print(\"for heat sink\")    \n",

-      "print(\"T_s-T_a=%.2f degC\" %dT)   \n",

-      "print(\"\\nP_av=%.0f W\" %P_av)\n",

-      "P=(V_m/2)**2/R\n",

-      "eff=P/(P+P_av)   \n",

-      "print(\"\\nckt efficiency=%.3f pu\" %eff)\n",

-      "a=60     #delay angle\n",

-      "I_TAV=(V_m/(2*math.pi*R))*(1+math.cos(math.radians(a)))\n",

-      "print(\"\\nI_TAV=%.2f A\" %I_TAV)\n",

-      "dT=46\n",

-      "T_s=dT+T_a\n",

-      "T_c=T_s+P_av*th_cs    \n",

-      "T_j=T_c+P_av*th_jc    \n",

-      "\n",

-      "#Results\n",

-      "print(\"\\ncase temp=%.2f degC\" %T_c)\n",

-      "print(\"\\njunction temp=%.2f degC\" %T_j)\n",

-      "\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for heat sink\n",

-        "T_s-T_a=-20.25 degC\n",

-        "\n",

-        "P_av=90 W\n",

-        "\n",

-        "ckt efficiency=0.993 pu\n",

-        "\n",

-        "I_TAV=38.83 A\n",

-        "\n",

-        "case temp=92.75 degC\n",

-        "\n",

-        "junction temp=106.25 degC\n"

-       ]

-      }

-     ],

-     "prompt_number": 11

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.20, Page No 187"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "T_j=125.0     #degC\n",

-      "T_s=70.0     #degC\n",

-      "th_jc=.16     #degC/W\n",

-      "th_cs=.08     #degC/W\n",

-      "\n",

-      "#Calculations\n",

-      "P_av1=(T_j-T_s)/(th_jc+th_cs)    \n",

-      "\n",

-      "T_s=60     #degC\n",

-      "P_av2=(T_j-T_s)/(th_jc+th_cs)    \n",

-      "inc=(math.sqrt(P_av2)-math.sqrt(P_av1))*100/math.sqrt(P_av1)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"Total avg power loss in thristor sink combination=%.2f W\" %P_av1)\n",

-      "print(\"Percentage inc in rating=%.2f\" %inc)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Total avg power loss in thristor sink combination=229.17 W\n",

-        "Percentage inc in rating=8.71\n"

-       ]

-      }

-     ],

-     "prompt_number": 12

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.21, Page No 197"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "\n",

-      "R=25000.0\n",

-      "I_l1=.021     #I_l=leakage current\n",

-      "I_l2=.025\n",

-      "I_l3=.018\n",

-      "I_l4=.016\n",

-      " #V1=(I-I_l1)*R\n",

-      " #V2=(I-I_l2)*R\n",

-      " #V3=(I-I_l3)*R\n",

-      " #V4=(I-I_l4)*R\n",

-      " #V=V1+V2+V3+V4\n",

-      "    \n",

-      "#Calculations\n",

-      "V=10000.0\n",

-      "I_l=I_l1+I_l2+I_l3+I_l4\n",

-      " #after solving\n",

-      "I=((V/R)+I_l)/4\n",

-      "R_c=40.0\n",

-      "V1=(I-I_l1)*R    \n",

-      "\n",

-      "#Resluts\n",

-      "print(\"voltage across SCR1=%.0f V\" %V1)\n",

-      "V2=(I-I_l2)*R    \n",

-      "print(\"\\nvoltage across SCR2=%.0f V\" %V2)\n",

-      "V3=(I-I_l3)*R    \n",

-      "print(\"\\nvoltage across SCR3=%.0f V\" %V3)\n",

-      "V4=(I-I_l4)*R    \n",

-      "print(\"\\nvoltage across SCR4=%.0f V\" %V4)\n",

-      "\n",

-      "I1=V1/R_c    \n",

-      "print(\"\\ndischarge current through SCR1=%.3f A\" %I1)\n",

-      "I2=V2/R_c   \n",

-      "print(\"\\ndischarge current through SCR2=%.3f A\" %I2)\n",

-      "I3=V3/R_c    \n",

-      "print(\"\\ndischarge current through SCR3=%.3f A\" %I3)\n",

-      "I4=V4/R_c    \n",

-      "print(\"\\ndischarge current through SCR4=%.3f A\" %I4)\n",

-      "\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "voltage across SCR1=2475 V\n",

-        "\n",

-        "voltage across SCR2=2375 V\n",

-        "\n",

-        "voltage across SCR3=2550 V\n",

-        "\n",

-        "voltage across SCR4=2600 V\n",

-        "\n",

-        "discharge current through SCR1=61.875 A\n",

-        "\n",

-        "discharge current through SCR2=59.375 A\n",

-        "\n",

-        "discharge current through SCR3=63.750 A\n",

-        "\n",

-        "discharge current through SCR4=65.000 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 13

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.22, Page No 198"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_r=1000     #rating of SCR\n",

-      "I_r=200     #rating of SCR\n",

-      "V_s=6000     #rating of String\n",

-      "I_s=1000     #rating of String\n",

-      "\n",

-      "#Calculations\n",

-      "print(\"when DRF=.1\")\n",

-      "DRF=.1\n",

-      "n_s=V_s/(V_r*(1-DRF))    \n",

-      "print(\"number of series units=%.0f\" %math.ceil(n_s))\n",

-      "n_p=I_s/(I_r*(1-DRF))    \n",

-      "print(\"\\nnumber of parrallel units=%.0f\" %math.ceil(n_p))\n",

-      "print(\"when DRF=.2\")\n",

-      "DRF=.2\n",

-      "\n",

-      "#Results\n",

-      "n_s=V_s/(V_r*(1-DRF))   \n",

-      "print(\"number of series units=%.0f\" %math.ceil(n_s))\n",

-      "n_p=I_s/(I_r*(1-DRF))    \n",

-      "print(\"\\nnumber of parrallel units=%.0f\" %math.ceil(n_p))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "when DRF=.1\n",

-        "number of series units=7\n",

-        "\n",

-        "number of parrallel units=6\n",

-        "when DRF=.2\n",

-        "number of series units=8\n",

-        "\n",

-        "number of parrallel units=7\n"

-       ]

-      }

-     ],

-     "prompt_number": 14

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.23, Page No 198"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V1=1.6     #on state voltage drop of SCR1\n",

-      "V2=1.2     #on state voltage drop of SCR2\n",

-      "I1=250.0     #current rating of SCR1\n",

-      "I2=350.0     #current rating of SCR2\n",

-      "\n",

-      "#Calculations\n",

-      "R1=V1/I1\n",

-      "R2=V2/I2\n",

-      "I=600.0     #current to be shared\n",

-      " #for SCR1 %     I*(R1+R)/(total resistance)=k*I1                    (1)\n",

-      " #for SCR2 %     I*(R2+R)/(total resistance)=k*I2                    (2)\n",

-      " #(1)/(2)\n",

-      "R=(R2*I2-R1*I1)/(I1-I2)\n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"RSequired value of resistance=%.3f ohm\" %R)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "RSequired value of resistance=0.004 ohm\n"

-       ]

-      }

-     ],

-     "prompt_number": 15

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.25, Page No 223"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "f=2000.0     #Hz\n",

-      "C=0.04*10**-6\n",

-      "n=.72\n",

-      "\n",

-      "#Calculations\n",

-      "R=1/(f*C*math.log(1/(1-n)))    \n",

-      "V_p=18\n",

-      "V_BB=V_p/n\n",

-      "R2=10**4/(n*V_BB)    \n",

-      "I=4.2*10**-3     #leakage current\n",

-      "R_BB=5000\n",

-      "R1=(V_BB/I)-R2-R_BB\n",

-      "\n",

-      "#Results\n",

-      "print(\"R=%.2f kilo-ohm\" %(R/1000))\n",

-      "print(\"\\nR2=%.2f ohm\" %R2)\n",

-      "print(\"\\nR1=%.0f ohm\" %R1)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "R=9.82 kilo-ohm\n",

-        "\n",

-        "R2=555.56 ohm\n",

-        "\n",

-        "R1=397 ohm\n"

-       ]

-      }

-     ],

-     "prompt_number": 16

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.26, Page No 223"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "\n",

-      "V_p=18.0\n",

-      "n=.72\n",

-      "V_BB=V_p/n\n",

-      "I_p=.6*10**-3\n",

-      "I_v=2.5*10**-3\n",

-      "V_v=1\n",

-      "\n",

-      "#Calculations\n",

-      "R_max=V_BB*(1-n)/I_p    \n",

-      "print(\"R_max=%.2f kilo-ohm\" %(R_max/1000))\n",

-      "R_min=(V_BB-V_v)/I_v    \n",

-      "print(\"\\nR_min=%.2f kilo-ohm\" %(R_min/1000))\n",

-      "\n",

-      "C=.04*10**-6\n",

-      "f_min=1/(R_max*C*math.log(1/(1-n)))    \n",

-      "print(\"\\nf_min=%.3f kHz\" %(f_min/1000))\n",

-      "f_max=1/(R_min*C*math.log(1/(1-n)))    \n",

-      "print(\"\\nf_max=%.2f kHz\" %(f_max/1000))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "R_max=11.67 kilo-ohm\n",

-        "\n",

-        "R_min=9.60 kilo-ohm\n",

-        "\n",

-        "f_min=1.683 kHz\n",

-        "\n",

-        "f_max=2.05 kHz\n"

-       ]

-      }

-     ],

-     "prompt_number": 17

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Power_Electronics/Chapter4_4.ipynb b/_Power_Electronics/Chapter4_4.ipynb
deleted file mode 100755
index 22311574..00000000
--- a/_Power_Electronics/Chapter4_4.ipynb
+++ /dev/null
@@ -1,946 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 04 : Thyristors"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.3, Page No 149"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "P=.5    #P=V_g*I_g\n",

-      "s=130    #s=V_g/I_g\n",

-      "\n",

-      "#Calculations\n",

-      "I_g=math.sqrt(P/s)\n",

-      "V_g=s*I_g\n",

-      "E=15\n",

-      "R_s=(E-V_g)/I_g    \n",

-      "\n",

-      "#Results\n",

-      "print(\"Gate source resistance=%.2f ohm\" %R_s)\n",

-      "#Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Gate source resistance=111.87 ohm\n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.4, Page No 149"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "\n",

-      "R_s=120     #slope of load line is -120V/A. This gives gate source resistance\n",

-      "print(\"gate source resistance=%.0f ohm\" %R_s)\n",

-      "\n",

-      "P=.4     #P=V_g*I_g\n",

-      "E_s=15\n",

-      "\n",

-      "#Calculations\n",

-      " #E_s=I_g*R_s+V_g %    after solving this\n",

-      " #120*I_g**2-15*I_g+0.4=0    so\n",

-      "a=120   \n",

-      "b=-15\n",

-      "c=0.4\n",

-      "D=math.sqrt((b**2)-4*a*c)\n",

-      "I_g=(-b+D)/(2*a)   \n",

-      "V_g=P/I_g\n",

-      "\n",

-      "#Results\n",

-      "print(\"\\ntrigger current=%.2f mA\" %(I_g*10**3))    \n",

-      "print(\"\\nthen trigger voltage=%.3f V\" %V_g)\n",

-      "I_g=(-b-D)/(2*a)   \n",

-      "V_g=P/I_g\n",

-      "print(\"\\ntrigger current=%.2f mA\" %(I_g*10**3))    \n",

-      "print(\"\\nthen trigger voltage=%.2f V\" %V_g)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "gate source resistance=120 ohm\n",

-        "\n",

-        "trigger current=86.44 mA\n",

-        "\n",

-        "then trigger voltage=4.628 V\n",

-        "\n",

-        "trigger current=38.56 mA\n",

-        "\n",

-        "then trigger voltage=10.37 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 2

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.5 Page No 150"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "\n",

-      "#V_g=1+10*I_g\n",

-      "P_gm=5     #P_gm=V_g*I_g\n",

-      "#after solving % eqn becomes 10*I_g**2+I_g-5=0\n",

-      "a=10.0    \n",

-      "b=1.0    \n",

-      "c=-5\n",

-      "\n",

-      "#Calculations\n",

-      "I_g=(-b+math.sqrt(b**2-4*a*c))/(2*a)\n",

-      "E_s=15\n",

-      "#using E_s=R_s*I_g+V_g\n",

-      "R_s=(E_s-1)/I_g-10   \n",

-      "P_gav=.3     #W\n",

-      "T=20*10**-6\n",

-      "f=P_gav/(P_gm*T)\n",

-      "dl=f*T\n",

-      "\n",

-      "#Results\n",

-      "print(\"Reistance=%.3f ohm\" %R_s)\n",

-      "print(\"Triggering freq=%.0f kHz\" %(f/1000))\n",

-      "print(\"Tduty cycle=%.2f\" %dl)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Reistance=11.248 ohm\n",

-        "Triggering freq=3 kHz\n",

-        "Tduty cycle=0.06\n"

-       ]

-      }

-     ],

-     "prompt_number": 3

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.6, Page No 151"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "I=.1\n",

-      "E=200.0\n",

-      "L=0.2\n",

-      "\n",

-      "#Calculations\n",

-      "t=I*L/E   \n",

-      "R=20.0\n",

-      "t1=(-L/R)*math.log(1-(R*I/E))    \n",

-      "L=2.0\n",

-      "t2=(-L/R)*math.log(1-(R*I/E))   \n",

-      "\n",

-      "#Results\n",

-      "print(\"in case load consists of (a)L=.2H\")\n",

-      "print(\"min gate pulse width=%.0f us\" %(t*10**6))\n",

-      "print(\"(b)R=20ohm in series with L=.2H\")\n",

-      "print(\"min gate pulse width=%.3f us\" %(t1*10**6))\n",

-      "print(\"(c)R=20ohm in series with L=2H\")\n",

-      "print(\"min gate pulse width=%.2f us\" %(t2*10**6))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "in case load consists of (a)L=.2H\n",

-        "min gate pulse width=100 us\n",

-        "(b)R=20ohm in series with L=.2H\n",

-        "min gate pulse width=100.503 us\n",

-        "(c)R=20ohm in series with L=2H\n",

-        "min gate pulse width=1005.03 us\n"

-       ]

-      }

-     ],

-     "prompt_number": 4

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.9 Page No 163"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "\n",

-      "def theta(th):\n",

-      "    I_m=1     #supposition\n",

-      "    I_av=(I_m/(2*math.pi))*(1+math.cos(math.radians(th)))\n",

-      "    I_rms=math.sqrt((I_m/(2*math.pi))*((180-th)*math.pi/360+.25*math.sin(math.radians(2*th))))\n",

-      "    FF=I_rms/I_av\n",

-      "    I_rms=35\n",

-      "    I_TAV=I_rms/FF\n",

-      "    return I_TAV\n",

-      "\n",

-      "#Calculations\n",

-      "print(\"when conduction angle=180\")\n",

-      "th=0\n",

-      "I_TAV=theta(th)\n",

-      "print(\"avg on current rating=%.3f A\" %I_TAV)\n",

-      "print(\"when conduction angle=90\")\n",

-      "th=90\n",

-      "I_TAV=theta(th)\n",

-      "\n",

-      "#Results\n",

-      "print(\"avg on current rating=%.3f A\" %I_TAV)\n",

-      "print(\"when conduction angle=30\")\n",

-      "th=150\n",

-      "I_TAV=theta(th)\n",

-      "print(\"avg on current rating=%.3f A\" %I_TAV)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "when conduction angle=180\n",

-        "avg on current rating=22.282 A\n",

-        "when conduction angle=90\n",

-        "avg on current rating=15.756 A\n",

-        "when conduction angle=30\n",

-        "avg on current rating=8.790 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 5

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.10, Page No 164"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "\n",

-      "def theta(th):\n",

-      "    n=360.0/th\n",

-      "    I=1.0     #supposition\n",

-      "    I_av=I/n\n",

-      "    I_rms=I/math.sqrt(n)\n",

-      "    FF=I_rms/I_av\n",

-      "    I_rms=35\n",

-      "    I_TAV=I_rms/FF\n",

-      "    return I_TAV\n",

-      "\n",

-      "#Calculations\n",

-      "th=180.0\n",

-      "I_TAV1=theta(th)\n",

-      "th=90.0\n",

-      "I_TAV2=theta(th)\n",

-      "th=30.0\n",

-      "I_TAV3=theta(th)\n",

-      "\n",

-      "#Results\n",

-      "print(\"when conduction angle=180\")\n",

-      "print(\"avg on current rating=%.3f A\" %I_TAV)\n",

-      "print(\"when conduction angle=90\")\n",

-      "print(\"avg on current rating=%.1f A\" %I_TAV2)\n",

-      "print(\"when conduction angle=30\")\n",

-      "print(\"avg on current rating=%.4f A\" %I_TAV3)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "when conduction angle=180\n",

-        "avg on current rating=8.790 A\n",

-        "when conduction angle=90\n",

-        "avg on current rating=17.5 A\n",

-        "when conduction angle=30\n",

-        "avg on current rating=10.1036 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 6

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.11 Page No 165"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math \n",

-      "\n",

-      "#initialisation of variables\n",

-      "f=50.0     #Hz\n",

-      "\n",

-      "#Calculations\n",

-      "I_sb=3000.0\n",

-      "t=1/(4*f)\n",

-      "T=1/(2*f)\n",

-      "I=math.sqrt(I_sb**2*t/T)    \n",

-      "r=(I_sb/math.sqrt(2))**2*T   \n",

-      "\n",

-      "#Results\n",

-      "print(\"surge current rating=%.2f A\" %I)\n",

-      "print(\"\\nI**2*t rating=%.0f A^2.s\" %r)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "surge current rating=2121.32 A\n",

-        "\n",

-        "I**2*t rating=45000 A^2.s\n"

-       ]

-      }

-     ],

-     "prompt_number": 7

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.12 Page No 165"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "\n",

-      "V_s=300.0 #V\n",

-      "R=60.0 #ohm\n",

-      "L=2.0 #H\n",

-      "\n",

-      "#Calculations\n",

-      "t=40*10**-6 #s\n",

-      "i_T=(V_s/R)*(1-math.exp(-R*t/L))\n",

-      "i=.036 #A\n",

-      "R1=V_s/(i-i_T)\n",

-      "\n",

-      "#Results\n",

-      "print(\"maximum value of remedial parameter=%.3f kilo-ohm\" %(R1/1000))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "maximum value of remedial parameter=9.999 kilo-ohm\n"

-       ]

-      }

-     ],

-     "prompt_number": 8

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.16 Page No 172"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "V_p=230.0*math.sqrt(2)\n",

-      "\n",

-      "#Calculations\n",

-      "R=1+((1)**-1+(10)**-1)**-1\n",

-      "A=V_p/R\n",

-      "s=1     #s\n",

-      "t_c=20*A**-2*s\n",

-      "\n",

-      "#Results\n",

-      "print(\"fault clearance time=%.4f ms\" %(t_c*10**3))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "fault clearance time=0.6890 ms\n"

-       ]

-      }

-     ],

-     "prompt_number": 9

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.17, Page No 176"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "\n",

-      "V_s=math.sqrt(2)*230     #V\n",

-      "L=15*10**-6     #H\n",

-      "I=V_s/L     #I=(di/dt)_max\n",

-      "R_s=10   #ohm\n",

-      "v=I*R_s     #v=(dv/dt)_max\n",

-      "\n",

-      "#Calculations\n",

-      "f=50     #Hz\n",

-      "X_L=L*2*math.pi*f\n",

-      "R=2\n",

-      "I_max=V_s/(R+X_L)    \n",

-      "FF=math.pi/math.sqrt(2)\n",

-      "I_TAV1=I_max/FF    \n",

-      "FF=3.98184\n",

-      "I_TAV2=I_max/FF    \n",

-      "\n",

-      "\n",

-      "#RESULTS\n",

-      "print(\"(di/dt)_max=%.3f A/usec\" %(I/10**6))\n",

-      "print(\"\\n(dv/dt)_max=%.2f V/usec\" %(v/10**6))\n",

-      "print(\"\\nI_rms=%.3f A\" %I_max)\n",

-      "print(\"when conduction angle=90\")\n",

-      "print(\"I_TAV=%.3f A\" %I_TAV1)\n",

-      "print(\"when conduction angle=30\")\n",

-      "print(\"I_TAV=%.3f A\" %I_TAV2)\n",

-      "print(\"\\nvoltage rating=%.3f V\" %(2.75*V_s)) #rating is taken 2.75 times of peak working voltage unlike 2.5 to 3 times as mentioned int book."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "(di/dt)_max=21.685 A/usec\n",

-        "\n",

-        "(dv/dt)_max=216.85 V/usec\n",

-        "\n",

-        "I_rms=162.252 A\n",

-        "when conduction angle=90\n",

-        "I_TAV=73.039 A\n",

-        "when conduction angle=30\n",

-        "I_TAV=40.748 A\n",

-        "\n",

-        "voltage rating=894.490 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 10

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.19, Page No 186"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "\n",

-      "T_jm=125\n",

-      "th_jc=.15     #degC/W\n",

-      "th_cs=0.075     #degC/W\n",

-      "\n",

-      "\n",

-      "#Calculations\n",

-      "dT=54     #dT=T_s-T_a\n",

-      "P_av=120\n",

-      "th_sa=dT/P_av\n",

-      "T_a=40     #ambient temp\n",

-      "P_av=(T_jm-T_a)/(th_sa+th_jc+th_cs)\n",

-      "if (P_av-120)<1 :\n",

-      "    print(\"selection of heat sink is satisfactory\")\n",

-      "\n",

-      "dT=58     #dT=T_s-T_a\n",

-      "P_av=120\n",

-      "th_sa=dT/P_av\n",

-      "T_a=40     #ambient temp\n",

-      "P_av=(T_jm-T_a)/(th_sa+th_jc+th_cs)\n",

-      "if (P_av-120)<1 :\n",

-      "    print(\"selection of heat sink is satisfactory\")\n",

-      "\n",

-      "V_m=math.sqrt(2)*230\n",

-      "R=2\n",

-      "I_TAV=V_m/(R*math.pi)\n",

-      "P_av=90\n",

-      "th_sa=(T_jm-T_a)/P_av-(th_jc+th_cs)\n",

-      "dT=P_av*th_sa\n",

-      "print(\"for heat sink\")    \n",

-      "print(\"T_s-T_a=%.2f degC\" %dT)   \n",

-      "print(\"\\nP_av=%.0f W\" %P_av)\n",

-      "P=(V_m/2)**2/R\n",

-      "eff=P/(P+P_av)   \n",

-      "print(\"\\nckt efficiency=%.3f pu\" %eff)\n",

-      "a=60     #delay angle\n",

-      "I_TAV=(V_m/(2*math.pi*R))*(1+math.cos(math.radians(a)))\n",

-      "print(\"\\nI_TAV=%.2f A\" %I_TAV)\n",

-      "dT=46\n",

-      "T_s=dT+T_a\n",

-      "T_c=T_s+P_av*th_cs    \n",

-      "T_j=T_c+P_av*th_jc    \n",

-      "\n",

-      "#Results\n",

-      "print(\"\\ncase temp=%.2f degC\" %T_c)\n",

-      "print(\"\\njunction temp=%.2f degC\" %T_j)\n",

-      "\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for heat sink\n",

-        "T_s-T_a=-20.25 degC\n",

-        "\n",

-        "P_av=90 W\n",

-        "\n",

-        "ckt efficiency=0.993 pu\n",

-        "\n",

-        "I_TAV=38.83 A\n",

-        "\n",

-        "case temp=92.75 degC\n",

-        "\n",

-        "junction temp=106.25 degC\n"

-       ]

-      }

-     ],

-     "prompt_number": 11

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.20, Page No 187"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "T_j=125.0     #degC\n",

-      "T_s=70.0     #degC\n",

-      "th_jc=.16     #degC/W\n",

-      "th_cs=.08     #degC/W\n",

-      "\n",

-      "#Calculations\n",

-      "P_av1=(T_j-T_s)/(th_jc+th_cs)    \n",

-      "\n",

-      "T_s=60     #degC\n",

-      "P_av2=(T_j-T_s)/(th_jc+th_cs)    \n",

-      "inc=(math.sqrt(P_av2)-math.sqrt(P_av1))*100/math.sqrt(P_av1)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"Total avg power loss in thristor sink combination=%.2f W\" %P_av1)\n",

-      "print(\"Percentage inc in rating=%.2f\" %inc)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Total avg power loss in thristor sink combination=229.17 W\n",

-        "Percentage inc in rating=8.71\n"

-       ]

-      }

-     ],

-     "prompt_number": 12

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.21, Page No 197"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "\n",

-      "R=25000.0\n",

-      "I_l1=.021     #I_l=leakage current\n",

-      "I_l2=.025\n",

-      "I_l3=.018\n",

-      "I_l4=.016\n",

-      " #V1=(I-I_l1)*R\n",

-      " #V2=(I-I_l2)*R\n",

-      " #V3=(I-I_l3)*R\n",

-      " #V4=(I-I_l4)*R\n",

-      " #V=V1+V2+V3+V4\n",

-      "    \n",

-      "#Calculations\n",

-      "V=10000.0\n",

-      "I_l=I_l1+I_l2+I_l3+I_l4\n",

-      " #after solving\n",

-      "I=((V/R)+I_l)/4\n",

-      "R_c=40.0\n",

-      "V1=(I-I_l1)*R    \n",

-      "\n",

-      "#Resluts\n",

-      "print(\"voltage across SCR1=%.0f V\" %V1)\n",

-      "V2=(I-I_l2)*R    \n",

-      "print(\"\\nvoltage across SCR2=%.0f V\" %V2)\n",

-      "V3=(I-I_l3)*R    \n",

-      "print(\"\\nvoltage across SCR3=%.0f V\" %V3)\n",

-      "V4=(I-I_l4)*R    \n",

-      "print(\"\\nvoltage across SCR4=%.0f V\" %V4)\n",

-      "\n",

-      "I1=V1/R_c    \n",

-      "print(\"\\ndischarge current through SCR1=%.3f A\" %I1)\n",

-      "I2=V2/R_c   \n",

-      "print(\"\\ndischarge current through SCR2=%.3f A\" %I2)\n",

-      "I3=V3/R_c    \n",

-      "print(\"\\ndischarge current through SCR3=%.3f A\" %I3)\n",

-      "I4=V4/R_c    \n",

-      "print(\"\\ndischarge current through SCR4=%.3f A\" %I4)\n",

-      "\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "voltage across SCR1=2475 V\n",

-        "\n",

-        "voltage across SCR2=2375 V\n",

-        "\n",

-        "voltage across SCR3=2550 V\n",

-        "\n",

-        "voltage across SCR4=2600 V\n",

-        "\n",

-        "discharge current through SCR1=61.875 A\n",

-        "\n",

-        "discharge current through SCR2=59.375 A\n",

-        "\n",

-        "discharge current through SCR3=63.750 A\n",

-        "\n",

-        "discharge current through SCR4=65.000 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 13

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.22, Page No 198"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_r=1000     #rating of SCR\n",

-      "I_r=200     #rating of SCR\n",

-      "V_s=6000     #rating of String\n",

-      "I_s=1000     #rating of String\n",

-      "\n",

-      "#Calculations\n",

-      "print(\"when DRF=.1\")\n",

-      "DRF=.1\n",

-      "n_s=V_s/(V_r*(1-DRF))    \n",

-      "print(\"number of series units=%.0f\" %math.ceil(n_s))\n",

-      "n_p=I_s/(I_r*(1-DRF))    \n",

-      "print(\"\\nnumber of parrallel units=%.0f\" %math.ceil(n_p))\n",

-      "print(\"when DRF=.2\")\n",

-      "DRF=.2\n",

-      "\n",

-      "#Results\n",

-      "n_s=V_s/(V_r*(1-DRF))   \n",

-      "print(\"number of series units=%.0f\" %math.ceil(n_s))\n",

-      "n_p=I_s/(I_r*(1-DRF))    \n",

-      "print(\"\\nnumber of parrallel units=%.0f\" %math.ceil(n_p))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "when DRF=.1\n",

-        "number of series units=7\n",

-        "\n",

-        "number of parrallel units=6\n",

-        "when DRF=.2\n",

-        "number of series units=8\n",

-        "\n",

-        "number of parrallel units=7\n"

-       ]

-      }

-     ],

-     "prompt_number": 14

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.23, Page No 198"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V1=1.6     #on state voltage drop of SCR1\n",

-      "V2=1.2     #on state voltage drop of SCR2\n",

-      "I1=250.0     #current rating of SCR1\n",

-      "I2=350.0     #current rating of SCR2\n",

-      "\n",

-      "#Calculations\n",

-      "R1=V1/I1\n",

-      "R2=V2/I2\n",

-      "I=600.0     #current to be shared\n",

-      " #for SCR1 %     I*(R1+R)/(total resistance)=k*I1                    (1)\n",

-      " #for SCR2 %     I*(R2+R)/(total resistance)=k*I2                    (2)\n",

-      " #(1)/(2)\n",

-      "R=(R2*I2-R1*I1)/(I1-I2)\n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"RSequired value of resistance=%.3f ohm\" %R)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "RSequired value of resistance=0.004 ohm\n"

-       ]

-      }

-     ],

-     "prompt_number": 15

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.25, Page No 223"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "f=2000.0     #Hz\n",

-      "C=0.04*10**-6\n",

-      "n=.72\n",

-      "\n",

-      "#Calculations\n",

-      "R=1/(f*C*math.log(1/(1-n)))    \n",

-      "V_p=18\n",

-      "V_BB=V_p/n\n",

-      "R2=10**4/(n*V_BB)    \n",

-      "I=4.2*10**-3     #leakage current\n",

-      "R_BB=5000\n",

-      "R1=(V_BB/I)-R2-R_BB\n",

-      "\n",

-      "#Results\n",

-      "print(\"R=%.2f kilo-ohm\" %(R/1000))\n",

-      "print(\"\\nR2=%.2f ohm\" %R2)\n",

-      "print(\"\\nR1=%.0f ohm\" %R1)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "R=9.82 kilo-ohm\n",

-        "\n",

-        "R2=555.56 ohm\n",

-        "\n",

-        "R1=397 ohm\n"

-       ]

-      }

-     ],

-     "prompt_number": 16

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 4.26, Page No 223"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "\n",

-      "V_p=18.0\n",

-      "n=.72\n",

-      "V_BB=V_p/n\n",

-      "I_p=.6*10**-3\n",

-      "I_v=2.5*10**-3\n",

-      "V_v=1\n",

-      "\n",

-      "#Calculations\n",

-      "R_max=V_BB*(1-n)/I_p    \n",

-      "print(\"R_max=%.2f kilo-ohm\" %(R_max/1000))\n",

-      "R_min=(V_BB-V_v)/I_v    \n",

-      "print(\"\\nR_min=%.2f kilo-ohm\" %(R_min/1000))\n",

-      "\n",

-      "C=.04*10**-6\n",

-      "f_min=1/(R_max*C*math.log(1/(1-n)))    \n",

-      "print(\"\\nf_min=%.3f kHz\" %(f_min/1000))\n",

-      "f_max=1/(R_min*C*math.log(1/(1-n)))    \n",

-      "print(\"\\nf_max=%.2f kHz\" %(f_max/1000))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "R_max=11.67 kilo-ohm\n",

-        "\n",

-        "R_min=9.60 kilo-ohm\n",

-        "\n",

-        "f_min=1.683 kHz\n",

-        "\n",

-        "f_max=2.05 kHz\n"

-       ]

-      }

-     ],

-     "prompt_number": 17

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Power_Electronics/Chapter5.ipynb b/_Power_Electronics/Chapter5.ipynb
deleted file mode 100755
index 1d261f20..00000000
--- a/_Power_Electronics/Chapter5.ipynb
+++ /dev/null
@@ -1,511 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 05 : Thyristor Commutation Techniques"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 5.1, Page No 252"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "L=5.0*10**-3            #mH\n",

-      "C=20.0*10**-6           #\u00b5F\n",

-      "V_s=200                 #V\n",

-      "\n",

-      "#Calculations\n",

-      "w_o=math.sqrt(1/(L*C))    #rad/s\n",

-      "t_o=math.pi/w_o           #ms\n",

-      "\n",

-      "#Results\n",

-      "print('conduction time of thyristor = %.2f ms' %(t_o*1000))\n",

-      "print('voltage across thyristor=%.0f V' %V_s)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "conduction time of thyristor = 0.99 ms\n",

-        "voltage across thyristor=200 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 12

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 5.2, Page No 255"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "C=20.0*10**-6         #\u00b5F\n",

-      "L=5.0*10**-6          #\u00b5H\n",

-      "V_s=230.0             #V\n",

-      "\n",

-      "#Calculations\n",

-      "I_p=V_s*math.sqrt(C/L)      #A\n",

-      "w_o=math.sqrt(1/(L*C))      #rad/sec\n",

-      "t_o=math.pi/w_o             #\u00b5S\n",

-      "I_o=300               \n",

-      "a = math.degrees(math.asin(I_o/(2*V_s)))   \n",

-      "V_ab = V_s*math.cos(math.radians(a))      #V \n",

-      "t_c=C*V_ab/I_o     #\u00b5s\n",

-      "\n",

-      "#Calculations\n",

-      "print(\"conduction time of auxillery thyristor=%.2f us\" %(t_o*10**6))\n",

-      "print(\"voltage across main thyristor=%.2f V\" %V_ab)\n",

-      "print(\"ckt turn off time=%.2f us\" %(t_c*10**6))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "conduction time of auxillery thyristor=31.42 us\n",

-        "voltage across main thyristor=174.36 V\n",

-        "ckt turn off time=11.62 us\n"

-       ]

-      }

-     ],

-     "prompt_number": 13

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 5.3 Page No 258"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "V_s=200.0           #V\n",

-      "R1=10.0             #\u2126\n",

-      "R2=100.0            #\u2126\n",

-      "C=0                 #  value of capacitor\n",

-      "\n",

-      "#Calculations\n",

-      "I1=V_s*(1/R1+2/R2)    #A\n",

-      "I2=V_s*(2/R1+1/R2)    #A\n",

-      "t_c1=40*10**-6\n",

-      "fos=2    #factor of safety\n",

-      "C1=t_c1*fos/(R1*math.log(2))\n",

-      "C2=t_c1*fos/(R2*math.log(2))\n",

-      "if C1 > C2 :\n",

-      "    C = C1*10**6\n",

-      "else :\n",

-      "    C = C2*10**6\n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"peak value of current through SCR1=%.2f A\" %I1); \n",

-      "print(\"Peak value of current through SCR2=%.2f A\" %I2);\n",

-      "print(\"Value of capacitor=%.2f uF\" %C);"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "peak value of current through SCR1=24.00 A\n",

-        "Peak value of current through SCR2=42.00 A\n",

-        "Value of capacitor=11.54 uF\n"

-       ]

-      }

-     ],

-     "prompt_number": 14

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 5.4, Page No 260"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0             #V\n",

-      "L=20*10**-6           #\u00b5H\n",

-      "C=40*10**-6           #\u00b5F\n",

-      "I_o=120.0             #A\n",

-      "\n",

-      "#Calculations\n",

-      "I_p=V_s*math.sqrt(C/L)   #A\n",

-      "t_c=C*V_s/I_o            #\u00b5s\n",

-      "w_o=math.sqrt(1/(L*C))  \n",

-      "t_c1=math.pi/(2*w_o)     #\u00b5s\n",

-      "\n",

-      "#Results\n",

-      "print(\"current through main thyristor=%.2f A\"  %(I_o+I_p))\n",

-      "print(\"Current through auxillery thyristor=%.2f A\" %I_o)\n",

-      "print(\"Circuit turn off time for main thyristor=%.2f us\" %(t_c*10**6))\n",

-      "print(\"Circuit turn off time for auxillery thyristor=%.2f us\" %(t_c1*10**6))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "current through main thyristor=445.27 A\n",

-        "Current through auxillery thyristor=120.00 A\n",

-        "Circuit turn off time for main thyristor=76.67 us\n",

-        "Circuit turn off time for auxillery thyristor=44.43 us\n"

-       ]

-      }

-     ],

-     "prompt_number": 15

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 5.5 Page No 263"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "C_j=25*10**-12      #pF\n",

-      "I_c=5*10**-3        #charging current\n",

-      "V_s=200.0           #V\n",

-      "R=50.0              #\u2126\n",

-      "\n",

-      "#Calculations\n",

-      "C=(C_j*V_s)/(I_c*R)\n",

-      "\n",

-      "\n",

-      "#RESULTS\n",

-      "print(\"Value of C=%.2f  \u00b5F\" %(C*10**6))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Value of C=0.02  \u00b5F\n"

-       ]

-      }

-     ],

-     "prompt_number": 16

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 5.6 Page No 263"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "V_s=200.0         #V\n",

-      "R=5.0             #\u2126\n",

-      "\n",

-      "#Calculations\n",

-      "C=10.0*10**-6\n",

-      "#for turn off V_s*(1-2*exp(-t/(R*C)))=0,    so after solving\n",

-      "t_c=R*C*math.log(2.0)\n",

-      "\n",

-      "#Results\n",

-      "print(\"circuit turn off time=%.2f us\" %(t_c*10**6))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "circuit turn off time=34.66 us\n"

-       ]

-      }

-     ],

-     "prompt_number": 17

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 5.7, Page No 264 "

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "R=1.0                   #\u2126\n",

-      "L=20*10**-6             #\u00b5H\n",

-      "C=40*10**-6             #\u00b5F\n",

-      "\n",

-      "#Calculations\n",

-      "w_r=math.sqrt((1/(L*C))-(R/(2*L))**2)\n",

-      "t_1=math.pi/w_r\n",

-      "\n",

-      "#Results\n",

-      "print(\"conduction time of thyristor=%.3f us\" %(t_1*10**6))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "conduction time of thyristor=125.664 us\n"

-       ]

-      }

-     ],

-     "prompt_number": 18

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 5.8 Page No 265"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math \n",

-      "\n",

-      "#initialisation of variables\n",

-      "dv=400*10.0**-6       #dv=dv_T/dt(V/s)\n",

-      "V_s=200.0             #v\n",

-      "R=20.0                #\u2126\n",

-      "\n",

-      "#Calculations\n",

-      "C=V_s/(R*dv)         \n",

-      "C_j=.025*10**-12\n",

-      "C_s=C-C_j\n",

-      "I_T=40;\n",

-      "R_s=1/((I_T/V_s)-(1/R)) \n",

-      "#value of R_s in book is wrongly calculated\n",

-      "\n",

-      "#Results\n",

-      "print(\"R_s=%.2f ohm\" %R_s)\n",

-      "print(\"C_s=%.3f uF\" %(C_s/10**6))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "R_s=6.67 ohm\n",

-        "C_s=0.025 uF\n"

-       ]

-      }

-     ],

-     "prompt_number": 19

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 5.9 Page No 265"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=200.0          #V\n",

-      "C=20.0*10**-6      #\u00b5H   \n",

-      "L=0.2*10**-3       #\u00b5F\n",

-      "i_c=10.0\n",

-      "\n",

-      "#Calculations\n",

-      "i=V_s*math.sqrt(C/L)\n",

-      "w_o=1.0/math.sqrt(L*C)\n",

-      "t_1 = (1/w_o)*math.degrees(math.asin(i_c/i))\n",

-      "t_o=math.pi/w_o\n",

-      "t_c=t_o-2*t_1    \n",

-      "\n",

-      "#Results\n",

-      "print(\"reqd time=%.2f us\" %(t_1*10**6))\n",

-      "print(\"ckt turn off time=%.2f us\" %(t_c*10**6))\n",

-      "print(\"ckt turn off time=%.5f us\" %t_1)\n",

-      "#solution in book wrong, as wrong values are selected while filling the formuleas"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "reqd time=575.37 us\n",

-        "ckt turn off time=-952.05 us\n",

-        "ckt turn off time=0.00058 us\n"

-       ]

-      }

-     ],

-     "prompt_number": 20

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 5.11 Page No 268 "

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "L=1.0              #\u00b5H\n",

-      "R=50.0             #\u2126\n",

-      "V_s=200.0          #V\n",

-      "t=0.01             #sec\n",

-      "Vd=0.7\n",

-      "\n",

-      "#Calculations\n",

-      "tau=L/R\n",

-      "i=(V_s/R)*(1-math.exp(-t/tau))\n",

-      "t=8*10**-3\n",

-      "i1=i-t*Vd  \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"current through L = %.2f A\" %i1)\n",

-      "i_R=0                  #current in R at t=.008s\n",

-      "print(\"Current through R = %.2f A\" %i_R)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "current through L = 1.57 A\n",

-        "Current through R = 0.00 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 21

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 5.12, Page No 269"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "\n",

-      "#initialisation of variables\n",

-      "L=1.0                      #H\n",

-      "R=50.0                   #ohm\n",

-      "V_s=200.0                #V\n",

-      "\n",

-      "#Calculations\n",

-      "tau=L/R\n",

-      "t=0.01                 #s\n",

-      "i=(V_s/R)*(1-math.exp(-t/tau))\n",

-      "C=1*10**-6            #F\n",

-      "V_c=math.sqrt(L/C)*i\n",

-      "\n",

-      "#Results\n",

-      "print(\"current in R,L=%.2f A\" %i)\n",

-      "print(\"voltage across C=%.2f kV\" %(V_c/1000))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "current in R,L=1.57 A\n",

-        "voltage across C=1.57 kV\n"

-       ]

-      }

-     ],

-     "prompt_number": 22

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Power_Electronics/Chapter5_1.ipynb b/_Power_Electronics/Chapter5_1.ipynb
deleted file mode 100755
index 1d261f20..00000000
--- a/_Power_Electronics/Chapter5_1.ipynb
+++ /dev/null
@@ -1,511 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 05 : Thyristor Commutation Techniques"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 5.1, Page No 252"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "L=5.0*10**-3            #mH\n",

-      "C=20.0*10**-6           #\u00b5F\n",

-      "V_s=200                 #V\n",

-      "\n",

-      "#Calculations\n",

-      "w_o=math.sqrt(1/(L*C))    #rad/s\n",

-      "t_o=math.pi/w_o           #ms\n",

-      "\n",

-      "#Results\n",

-      "print('conduction time of thyristor = %.2f ms' %(t_o*1000))\n",

-      "print('voltage across thyristor=%.0f V' %V_s)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "conduction time of thyristor = 0.99 ms\n",

-        "voltage across thyristor=200 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 12

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 5.2, Page No 255"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "C=20.0*10**-6         #\u00b5F\n",

-      "L=5.0*10**-6          #\u00b5H\n",

-      "V_s=230.0             #V\n",

-      "\n",

-      "#Calculations\n",

-      "I_p=V_s*math.sqrt(C/L)      #A\n",

-      "w_o=math.sqrt(1/(L*C))      #rad/sec\n",

-      "t_o=math.pi/w_o             #\u00b5S\n",

-      "I_o=300               \n",

-      "a = math.degrees(math.asin(I_o/(2*V_s)))   \n",

-      "V_ab = V_s*math.cos(math.radians(a))      #V \n",

-      "t_c=C*V_ab/I_o     #\u00b5s\n",

-      "\n",

-      "#Calculations\n",

-      "print(\"conduction time of auxillery thyristor=%.2f us\" %(t_o*10**6))\n",

-      "print(\"voltage across main thyristor=%.2f V\" %V_ab)\n",

-      "print(\"ckt turn off time=%.2f us\" %(t_c*10**6))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "conduction time of auxillery thyristor=31.42 us\n",

-        "voltage across main thyristor=174.36 V\n",

-        "ckt turn off time=11.62 us\n"

-       ]

-      }

-     ],

-     "prompt_number": 13

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 5.3 Page No 258"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "V_s=200.0           #V\n",

-      "R1=10.0             #\u2126\n",

-      "R2=100.0            #\u2126\n",

-      "C=0                 #  value of capacitor\n",

-      "\n",

-      "#Calculations\n",

-      "I1=V_s*(1/R1+2/R2)    #A\n",

-      "I2=V_s*(2/R1+1/R2)    #A\n",

-      "t_c1=40*10**-6\n",

-      "fos=2    #factor of safety\n",

-      "C1=t_c1*fos/(R1*math.log(2))\n",

-      "C2=t_c1*fos/(R2*math.log(2))\n",

-      "if C1 > C2 :\n",

-      "    C = C1*10**6\n",

-      "else :\n",

-      "    C = C2*10**6\n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"peak value of current through SCR1=%.2f A\" %I1); \n",

-      "print(\"Peak value of current through SCR2=%.2f A\" %I2);\n",

-      "print(\"Value of capacitor=%.2f uF\" %C);"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "peak value of current through SCR1=24.00 A\n",

-        "Peak value of current through SCR2=42.00 A\n",

-        "Value of capacitor=11.54 uF\n"

-       ]

-      }

-     ],

-     "prompt_number": 14

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 5.4, Page No 260"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0             #V\n",

-      "L=20*10**-6           #\u00b5H\n",

-      "C=40*10**-6           #\u00b5F\n",

-      "I_o=120.0             #A\n",

-      "\n",

-      "#Calculations\n",

-      "I_p=V_s*math.sqrt(C/L)   #A\n",

-      "t_c=C*V_s/I_o            #\u00b5s\n",

-      "w_o=math.sqrt(1/(L*C))  \n",

-      "t_c1=math.pi/(2*w_o)     #\u00b5s\n",

-      "\n",

-      "#Results\n",

-      "print(\"current through main thyristor=%.2f A\"  %(I_o+I_p))\n",

-      "print(\"Current through auxillery thyristor=%.2f A\" %I_o)\n",

-      "print(\"Circuit turn off time for main thyristor=%.2f us\" %(t_c*10**6))\n",

-      "print(\"Circuit turn off time for auxillery thyristor=%.2f us\" %(t_c1*10**6))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "current through main thyristor=445.27 A\n",

-        "Current through auxillery thyristor=120.00 A\n",

-        "Circuit turn off time for main thyristor=76.67 us\n",

-        "Circuit turn off time for auxillery thyristor=44.43 us\n"

-       ]

-      }

-     ],

-     "prompt_number": 15

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 5.5 Page No 263"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "C_j=25*10**-12      #pF\n",

-      "I_c=5*10**-3        #charging current\n",

-      "V_s=200.0           #V\n",

-      "R=50.0              #\u2126\n",

-      "\n",

-      "#Calculations\n",

-      "C=(C_j*V_s)/(I_c*R)\n",

-      "\n",

-      "\n",

-      "#RESULTS\n",

-      "print(\"Value of C=%.2f  \u00b5F\" %(C*10**6))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Value of C=0.02  \u00b5F\n"

-       ]

-      }

-     ],

-     "prompt_number": 16

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 5.6 Page No 263"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "V_s=200.0         #V\n",

-      "R=5.0             #\u2126\n",

-      "\n",

-      "#Calculations\n",

-      "C=10.0*10**-6\n",

-      "#for turn off V_s*(1-2*exp(-t/(R*C)))=0,    so after solving\n",

-      "t_c=R*C*math.log(2.0)\n",

-      "\n",

-      "#Results\n",

-      "print(\"circuit turn off time=%.2f us\" %(t_c*10**6))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "circuit turn off time=34.66 us\n"

-       ]

-      }

-     ],

-     "prompt_number": 17

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 5.7, Page No 264 "

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "R=1.0                   #\u2126\n",

-      "L=20*10**-6             #\u00b5H\n",

-      "C=40*10**-6             #\u00b5F\n",

-      "\n",

-      "#Calculations\n",

-      "w_r=math.sqrt((1/(L*C))-(R/(2*L))**2)\n",

-      "t_1=math.pi/w_r\n",

-      "\n",

-      "#Results\n",

-      "print(\"conduction time of thyristor=%.3f us\" %(t_1*10**6))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "conduction time of thyristor=125.664 us\n"

-       ]

-      }

-     ],

-     "prompt_number": 18

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 5.8 Page No 265"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math \n",

-      "\n",

-      "#initialisation of variables\n",

-      "dv=400*10.0**-6       #dv=dv_T/dt(V/s)\n",

-      "V_s=200.0             #v\n",

-      "R=20.0                #\u2126\n",

-      "\n",

-      "#Calculations\n",

-      "C=V_s/(R*dv)         \n",

-      "C_j=.025*10**-12\n",

-      "C_s=C-C_j\n",

-      "I_T=40;\n",

-      "R_s=1/((I_T/V_s)-(1/R)) \n",

-      "#value of R_s in book is wrongly calculated\n",

-      "\n",

-      "#Results\n",

-      "print(\"R_s=%.2f ohm\" %R_s)\n",

-      "print(\"C_s=%.3f uF\" %(C_s/10**6))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "R_s=6.67 ohm\n",

-        "C_s=0.025 uF\n"

-       ]

-      }

-     ],

-     "prompt_number": 19

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 5.9 Page No 265"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=200.0          #V\n",

-      "C=20.0*10**-6      #\u00b5H   \n",

-      "L=0.2*10**-3       #\u00b5F\n",

-      "i_c=10.0\n",

-      "\n",

-      "#Calculations\n",

-      "i=V_s*math.sqrt(C/L)\n",

-      "w_o=1.0/math.sqrt(L*C)\n",

-      "t_1 = (1/w_o)*math.degrees(math.asin(i_c/i))\n",

-      "t_o=math.pi/w_o\n",

-      "t_c=t_o-2*t_1    \n",

-      "\n",

-      "#Results\n",

-      "print(\"reqd time=%.2f us\" %(t_1*10**6))\n",

-      "print(\"ckt turn off time=%.2f us\" %(t_c*10**6))\n",

-      "print(\"ckt turn off time=%.5f us\" %t_1)\n",

-      "#solution in book wrong, as wrong values are selected while filling the formuleas"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "reqd time=575.37 us\n",

-        "ckt turn off time=-952.05 us\n",

-        "ckt turn off time=0.00058 us\n"

-       ]

-      }

-     ],

-     "prompt_number": 20

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 5.11 Page No 268 "

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "L=1.0              #\u00b5H\n",

-      "R=50.0             #\u2126\n",

-      "V_s=200.0          #V\n",

-      "t=0.01             #sec\n",

-      "Vd=0.7\n",

-      "\n",

-      "#Calculations\n",

-      "tau=L/R\n",

-      "i=(V_s/R)*(1-math.exp(-t/tau))\n",

-      "t=8*10**-3\n",

-      "i1=i-t*Vd  \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"current through L = %.2f A\" %i1)\n",

-      "i_R=0                  #current in R at t=.008s\n",

-      "print(\"Current through R = %.2f A\" %i_R)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "current through L = 1.57 A\n",

-        "Current through R = 0.00 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 21

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 5.12, Page No 269"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "\n",

-      "#initialisation of variables\n",

-      "L=1.0                      #H\n",

-      "R=50.0                   #ohm\n",

-      "V_s=200.0                #V\n",

-      "\n",

-      "#Calculations\n",

-      "tau=L/R\n",

-      "t=0.01                 #s\n",

-      "i=(V_s/R)*(1-math.exp(-t/tau))\n",

-      "C=1*10**-6            #F\n",

-      "V_c=math.sqrt(L/C)*i\n",

-      "\n",

-      "#Results\n",

-      "print(\"current in R,L=%.2f A\" %i)\n",

-      "print(\"voltage across C=%.2f kV\" %(V_c/1000))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "current in R,L=1.57 A\n",

-        "voltage across C=1.57 kV\n"

-       ]

-      }

-     ],

-     "prompt_number": 22

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Power_Electronics/Chapter5_2.ipynb b/_Power_Electronics/Chapter5_2.ipynb
deleted file mode 100755
index 1d261f20..00000000
--- a/_Power_Electronics/Chapter5_2.ipynb
+++ /dev/null
@@ -1,511 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 05 : Thyristor Commutation Techniques"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 5.1, Page No 252"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "L=5.0*10**-3            #mH\n",

-      "C=20.0*10**-6           #\u00b5F\n",

-      "V_s=200                 #V\n",

-      "\n",

-      "#Calculations\n",

-      "w_o=math.sqrt(1/(L*C))    #rad/s\n",

-      "t_o=math.pi/w_o           #ms\n",

-      "\n",

-      "#Results\n",

-      "print('conduction time of thyristor = %.2f ms' %(t_o*1000))\n",

-      "print('voltage across thyristor=%.0f V' %V_s)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "conduction time of thyristor = 0.99 ms\n",

-        "voltage across thyristor=200 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 12

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 5.2, Page No 255"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "C=20.0*10**-6         #\u00b5F\n",

-      "L=5.0*10**-6          #\u00b5H\n",

-      "V_s=230.0             #V\n",

-      "\n",

-      "#Calculations\n",

-      "I_p=V_s*math.sqrt(C/L)      #A\n",

-      "w_o=math.sqrt(1/(L*C))      #rad/sec\n",

-      "t_o=math.pi/w_o             #\u00b5S\n",

-      "I_o=300               \n",

-      "a = math.degrees(math.asin(I_o/(2*V_s)))   \n",

-      "V_ab = V_s*math.cos(math.radians(a))      #V \n",

-      "t_c=C*V_ab/I_o     #\u00b5s\n",

-      "\n",

-      "#Calculations\n",

-      "print(\"conduction time of auxillery thyristor=%.2f us\" %(t_o*10**6))\n",

-      "print(\"voltage across main thyristor=%.2f V\" %V_ab)\n",

-      "print(\"ckt turn off time=%.2f us\" %(t_c*10**6))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "conduction time of auxillery thyristor=31.42 us\n",

-        "voltage across main thyristor=174.36 V\n",

-        "ckt turn off time=11.62 us\n"

-       ]

-      }

-     ],

-     "prompt_number": 13

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 5.3 Page No 258"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "V_s=200.0           #V\n",

-      "R1=10.0             #\u2126\n",

-      "R2=100.0            #\u2126\n",

-      "C=0                 #  value of capacitor\n",

-      "\n",

-      "#Calculations\n",

-      "I1=V_s*(1/R1+2/R2)    #A\n",

-      "I2=V_s*(2/R1+1/R2)    #A\n",

-      "t_c1=40*10**-6\n",

-      "fos=2    #factor of safety\n",

-      "C1=t_c1*fos/(R1*math.log(2))\n",

-      "C2=t_c1*fos/(R2*math.log(2))\n",

-      "if C1 > C2 :\n",

-      "    C = C1*10**6\n",

-      "else :\n",

-      "    C = C2*10**6\n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"peak value of current through SCR1=%.2f A\" %I1); \n",

-      "print(\"Peak value of current through SCR2=%.2f A\" %I2);\n",

-      "print(\"Value of capacitor=%.2f uF\" %C);"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "peak value of current through SCR1=24.00 A\n",

-        "Peak value of current through SCR2=42.00 A\n",

-        "Value of capacitor=11.54 uF\n"

-       ]

-      }

-     ],

-     "prompt_number": 14

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 5.4, Page No 260"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0             #V\n",

-      "L=20*10**-6           #\u00b5H\n",

-      "C=40*10**-6           #\u00b5F\n",

-      "I_o=120.0             #A\n",

-      "\n",

-      "#Calculations\n",

-      "I_p=V_s*math.sqrt(C/L)   #A\n",

-      "t_c=C*V_s/I_o            #\u00b5s\n",

-      "w_o=math.sqrt(1/(L*C))  \n",

-      "t_c1=math.pi/(2*w_o)     #\u00b5s\n",

-      "\n",

-      "#Results\n",

-      "print(\"current through main thyristor=%.2f A\"  %(I_o+I_p))\n",

-      "print(\"Current through auxillery thyristor=%.2f A\" %I_o)\n",

-      "print(\"Circuit turn off time for main thyristor=%.2f us\" %(t_c*10**6))\n",

-      "print(\"Circuit turn off time for auxillery thyristor=%.2f us\" %(t_c1*10**6))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "current through main thyristor=445.27 A\n",

-        "Current through auxillery thyristor=120.00 A\n",

-        "Circuit turn off time for main thyristor=76.67 us\n",

-        "Circuit turn off time for auxillery thyristor=44.43 us\n"

-       ]

-      }

-     ],

-     "prompt_number": 15

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 5.5 Page No 263"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "C_j=25*10**-12      #pF\n",

-      "I_c=5*10**-3        #charging current\n",

-      "V_s=200.0           #V\n",

-      "R=50.0              #\u2126\n",

-      "\n",

-      "#Calculations\n",

-      "C=(C_j*V_s)/(I_c*R)\n",

-      "\n",

-      "\n",

-      "#RESULTS\n",

-      "print(\"Value of C=%.2f  \u00b5F\" %(C*10**6))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Value of C=0.02  \u00b5F\n"

-       ]

-      }

-     ],

-     "prompt_number": 16

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 5.6 Page No 263"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "V_s=200.0         #V\n",

-      "R=5.0             #\u2126\n",

-      "\n",

-      "#Calculations\n",

-      "C=10.0*10**-6\n",

-      "#for turn off V_s*(1-2*exp(-t/(R*C)))=0,    so after solving\n",

-      "t_c=R*C*math.log(2.0)\n",

-      "\n",

-      "#Results\n",

-      "print(\"circuit turn off time=%.2f us\" %(t_c*10**6))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "circuit turn off time=34.66 us\n"

-       ]

-      }

-     ],

-     "prompt_number": 17

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 5.7, Page No 264 "

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "R=1.0                   #\u2126\n",

-      "L=20*10**-6             #\u00b5H\n",

-      "C=40*10**-6             #\u00b5F\n",

-      "\n",

-      "#Calculations\n",

-      "w_r=math.sqrt((1/(L*C))-(R/(2*L))**2)\n",

-      "t_1=math.pi/w_r\n",

-      "\n",

-      "#Results\n",

-      "print(\"conduction time of thyristor=%.3f us\" %(t_1*10**6))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "conduction time of thyristor=125.664 us\n"

-       ]

-      }

-     ],

-     "prompt_number": 18

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 5.8 Page No 265"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math \n",

-      "\n",

-      "#initialisation of variables\n",

-      "dv=400*10.0**-6       #dv=dv_T/dt(V/s)\n",

-      "V_s=200.0             #v\n",

-      "R=20.0                #\u2126\n",

-      "\n",

-      "#Calculations\n",

-      "C=V_s/(R*dv)         \n",

-      "C_j=.025*10**-12\n",

-      "C_s=C-C_j\n",

-      "I_T=40;\n",

-      "R_s=1/((I_T/V_s)-(1/R)) \n",

-      "#value of R_s in book is wrongly calculated\n",

-      "\n",

-      "#Results\n",

-      "print(\"R_s=%.2f ohm\" %R_s)\n",

-      "print(\"C_s=%.3f uF\" %(C_s/10**6))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "R_s=6.67 ohm\n",

-        "C_s=0.025 uF\n"

-       ]

-      }

-     ],

-     "prompt_number": 19

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 5.9 Page No 265"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=200.0          #V\n",

-      "C=20.0*10**-6      #\u00b5H   \n",

-      "L=0.2*10**-3       #\u00b5F\n",

-      "i_c=10.0\n",

-      "\n",

-      "#Calculations\n",

-      "i=V_s*math.sqrt(C/L)\n",

-      "w_o=1.0/math.sqrt(L*C)\n",

-      "t_1 = (1/w_o)*math.degrees(math.asin(i_c/i))\n",

-      "t_o=math.pi/w_o\n",

-      "t_c=t_o-2*t_1    \n",

-      "\n",

-      "#Results\n",

-      "print(\"reqd time=%.2f us\" %(t_1*10**6))\n",

-      "print(\"ckt turn off time=%.2f us\" %(t_c*10**6))\n",

-      "print(\"ckt turn off time=%.5f us\" %t_1)\n",

-      "#solution in book wrong, as wrong values are selected while filling the formuleas"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "reqd time=575.37 us\n",

-        "ckt turn off time=-952.05 us\n",

-        "ckt turn off time=0.00058 us\n"

-       ]

-      }

-     ],

-     "prompt_number": 20

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 5.11 Page No 268 "

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "L=1.0              #\u00b5H\n",

-      "R=50.0             #\u2126\n",

-      "V_s=200.0          #V\n",

-      "t=0.01             #sec\n",

-      "Vd=0.7\n",

-      "\n",

-      "#Calculations\n",

-      "tau=L/R\n",

-      "i=(V_s/R)*(1-math.exp(-t/tau))\n",

-      "t=8*10**-3\n",

-      "i1=i-t*Vd  \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"current through L = %.2f A\" %i1)\n",

-      "i_R=0                  #current in R at t=.008s\n",

-      "print(\"Current through R = %.2f A\" %i_R)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "current through L = 1.57 A\n",

-        "Current through R = 0.00 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 21

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 5.12, Page No 269"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "\n",

-      "#initialisation of variables\n",

-      "L=1.0                      #H\n",

-      "R=50.0                   #ohm\n",

-      "V_s=200.0                #V\n",

-      "\n",

-      "#Calculations\n",

-      "tau=L/R\n",

-      "t=0.01                 #s\n",

-      "i=(V_s/R)*(1-math.exp(-t/tau))\n",

-      "C=1*10**-6            #F\n",

-      "V_c=math.sqrt(L/C)*i\n",

-      "\n",

-      "#Results\n",

-      "print(\"current in R,L=%.2f A\" %i)\n",

-      "print(\"voltage across C=%.2f kV\" %(V_c/1000))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "current in R,L=1.57 A\n",

-        "voltage across C=1.57 kV\n"

-       ]

-      }

-     ],

-     "prompt_number": 22

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Power_Electronics/Chapter5_3.ipynb b/_Power_Electronics/Chapter5_3.ipynb
deleted file mode 100755
index 1d261f20..00000000
--- a/_Power_Electronics/Chapter5_3.ipynb
+++ /dev/null
@@ -1,511 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 05 : Thyristor Commutation Techniques"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 5.1, Page No 252"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "L=5.0*10**-3            #mH\n",

-      "C=20.0*10**-6           #\u00b5F\n",

-      "V_s=200                 #V\n",

-      "\n",

-      "#Calculations\n",

-      "w_o=math.sqrt(1/(L*C))    #rad/s\n",

-      "t_o=math.pi/w_o           #ms\n",

-      "\n",

-      "#Results\n",

-      "print('conduction time of thyristor = %.2f ms' %(t_o*1000))\n",

-      "print('voltage across thyristor=%.0f V' %V_s)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "conduction time of thyristor = 0.99 ms\n",

-        "voltage across thyristor=200 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 12

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 5.2, Page No 255"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "C=20.0*10**-6         #\u00b5F\n",

-      "L=5.0*10**-6          #\u00b5H\n",

-      "V_s=230.0             #V\n",

-      "\n",

-      "#Calculations\n",

-      "I_p=V_s*math.sqrt(C/L)      #A\n",

-      "w_o=math.sqrt(1/(L*C))      #rad/sec\n",

-      "t_o=math.pi/w_o             #\u00b5S\n",

-      "I_o=300               \n",

-      "a = math.degrees(math.asin(I_o/(2*V_s)))   \n",

-      "V_ab = V_s*math.cos(math.radians(a))      #V \n",

-      "t_c=C*V_ab/I_o     #\u00b5s\n",

-      "\n",

-      "#Calculations\n",

-      "print(\"conduction time of auxillery thyristor=%.2f us\" %(t_o*10**6))\n",

-      "print(\"voltage across main thyristor=%.2f V\" %V_ab)\n",

-      "print(\"ckt turn off time=%.2f us\" %(t_c*10**6))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "conduction time of auxillery thyristor=31.42 us\n",

-        "voltage across main thyristor=174.36 V\n",

-        "ckt turn off time=11.62 us\n"

-       ]

-      }

-     ],

-     "prompt_number": 13

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 5.3 Page No 258"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "V_s=200.0           #V\n",

-      "R1=10.0             #\u2126\n",

-      "R2=100.0            #\u2126\n",

-      "C=0                 #  value of capacitor\n",

-      "\n",

-      "#Calculations\n",

-      "I1=V_s*(1/R1+2/R2)    #A\n",

-      "I2=V_s*(2/R1+1/R2)    #A\n",

-      "t_c1=40*10**-6\n",

-      "fos=2    #factor of safety\n",

-      "C1=t_c1*fos/(R1*math.log(2))\n",

-      "C2=t_c1*fos/(R2*math.log(2))\n",

-      "if C1 > C2 :\n",

-      "    C = C1*10**6\n",

-      "else :\n",

-      "    C = C2*10**6\n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"peak value of current through SCR1=%.2f A\" %I1); \n",

-      "print(\"Peak value of current through SCR2=%.2f A\" %I2);\n",

-      "print(\"Value of capacitor=%.2f uF\" %C);"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "peak value of current through SCR1=24.00 A\n",

-        "Peak value of current through SCR2=42.00 A\n",

-        "Value of capacitor=11.54 uF\n"

-       ]

-      }

-     ],

-     "prompt_number": 14

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 5.4, Page No 260"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0             #V\n",

-      "L=20*10**-6           #\u00b5H\n",

-      "C=40*10**-6           #\u00b5F\n",

-      "I_o=120.0             #A\n",

-      "\n",

-      "#Calculations\n",

-      "I_p=V_s*math.sqrt(C/L)   #A\n",

-      "t_c=C*V_s/I_o            #\u00b5s\n",

-      "w_o=math.sqrt(1/(L*C))  \n",

-      "t_c1=math.pi/(2*w_o)     #\u00b5s\n",

-      "\n",

-      "#Results\n",

-      "print(\"current through main thyristor=%.2f A\"  %(I_o+I_p))\n",

-      "print(\"Current through auxillery thyristor=%.2f A\" %I_o)\n",

-      "print(\"Circuit turn off time for main thyristor=%.2f us\" %(t_c*10**6))\n",

-      "print(\"Circuit turn off time for auxillery thyristor=%.2f us\" %(t_c1*10**6))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "current through main thyristor=445.27 A\n",

-        "Current through auxillery thyristor=120.00 A\n",

-        "Circuit turn off time for main thyristor=76.67 us\n",

-        "Circuit turn off time for auxillery thyristor=44.43 us\n"

-       ]

-      }

-     ],

-     "prompt_number": 15

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 5.5 Page No 263"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "C_j=25*10**-12      #pF\n",

-      "I_c=5*10**-3        #charging current\n",

-      "V_s=200.0           #V\n",

-      "R=50.0              #\u2126\n",

-      "\n",

-      "#Calculations\n",

-      "C=(C_j*V_s)/(I_c*R)\n",

-      "\n",

-      "\n",

-      "#RESULTS\n",

-      "print(\"Value of C=%.2f  \u00b5F\" %(C*10**6))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Value of C=0.02  \u00b5F\n"

-       ]

-      }

-     ],

-     "prompt_number": 16

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 5.6 Page No 263"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "V_s=200.0         #V\n",

-      "R=5.0             #\u2126\n",

-      "\n",

-      "#Calculations\n",

-      "C=10.0*10**-6\n",

-      "#for turn off V_s*(1-2*exp(-t/(R*C)))=0,    so after solving\n",

-      "t_c=R*C*math.log(2.0)\n",

-      "\n",

-      "#Results\n",

-      "print(\"circuit turn off time=%.2f us\" %(t_c*10**6))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "circuit turn off time=34.66 us\n"

-       ]

-      }

-     ],

-     "prompt_number": 17

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 5.7, Page No 264 "

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "R=1.0                   #\u2126\n",

-      "L=20*10**-6             #\u00b5H\n",

-      "C=40*10**-6             #\u00b5F\n",

-      "\n",

-      "#Calculations\n",

-      "w_r=math.sqrt((1/(L*C))-(R/(2*L))**2)\n",

-      "t_1=math.pi/w_r\n",

-      "\n",

-      "#Results\n",

-      "print(\"conduction time of thyristor=%.3f us\" %(t_1*10**6))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "conduction time of thyristor=125.664 us\n"

-       ]

-      }

-     ],

-     "prompt_number": 18

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 5.8 Page No 265"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math \n",

-      "\n",

-      "#initialisation of variables\n",

-      "dv=400*10.0**-6       #dv=dv_T/dt(V/s)\n",

-      "V_s=200.0             #v\n",

-      "R=20.0                #\u2126\n",

-      "\n",

-      "#Calculations\n",

-      "C=V_s/(R*dv)         \n",

-      "C_j=.025*10**-12\n",

-      "C_s=C-C_j\n",

-      "I_T=40;\n",

-      "R_s=1/((I_T/V_s)-(1/R)) \n",

-      "#value of R_s in book is wrongly calculated\n",

-      "\n",

-      "#Results\n",

-      "print(\"R_s=%.2f ohm\" %R_s)\n",

-      "print(\"C_s=%.3f uF\" %(C_s/10**6))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "R_s=6.67 ohm\n",

-        "C_s=0.025 uF\n"

-       ]

-      }

-     ],

-     "prompt_number": 19

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 5.9 Page No 265"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=200.0          #V\n",

-      "C=20.0*10**-6      #\u00b5H   \n",

-      "L=0.2*10**-3       #\u00b5F\n",

-      "i_c=10.0\n",

-      "\n",

-      "#Calculations\n",

-      "i=V_s*math.sqrt(C/L)\n",

-      "w_o=1.0/math.sqrt(L*C)\n",

-      "t_1 = (1/w_o)*math.degrees(math.asin(i_c/i))\n",

-      "t_o=math.pi/w_o\n",

-      "t_c=t_o-2*t_1    \n",

-      "\n",

-      "#Results\n",

-      "print(\"reqd time=%.2f us\" %(t_1*10**6))\n",

-      "print(\"ckt turn off time=%.2f us\" %(t_c*10**6))\n",

-      "print(\"ckt turn off time=%.5f us\" %t_1)\n",

-      "#solution in book wrong, as wrong values are selected while filling the formuleas"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "reqd time=575.37 us\n",

-        "ckt turn off time=-952.05 us\n",

-        "ckt turn off time=0.00058 us\n"

-       ]

-      }

-     ],

-     "prompt_number": 20

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 5.11 Page No 268 "

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "L=1.0              #\u00b5H\n",

-      "R=50.0             #\u2126\n",

-      "V_s=200.0          #V\n",

-      "t=0.01             #sec\n",

-      "Vd=0.7\n",

-      "\n",

-      "#Calculations\n",

-      "tau=L/R\n",

-      "i=(V_s/R)*(1-math.exp(-t/tau))\n",

-      "t=8*10**-3\n",

-      "i1=i-t*Vd  \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"current through L = %.2f A\" %i1)\n",

-      "i_R=0                  #current in R at t=.008s\n",

-      "print(\"Current through R = %.2f A\" %i_R)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "current through L = 1.57 A\n",

-        "Current through R = 0.00 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 21

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 5.12, Page No 269"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "\n",

-      "#initialisation of variables\n",

-      "L=1.0                      #H\n",

-      "R=50.0                   #ohm\n",

-      "V_s=200.0                #V\n",

-      "\n",

-      "#Calculations\n",

-      "tau=L/R\n",

-      "t=0.01                 #s\n",

-      "i=(V_s/R)*(1-math.exp(-t/tau))\n",

-      "C=1*10**-6            #F\n",

-      "V_c=math.sqrt(L/C)*i\n",

-      "\n",

-      "#Results\n",

-      "print(\"current in R,L=%.2f A\" %i)\n",

-      "print(\"voltage across C=%.2f kV\" %(V_c/1000))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "current in R,L=1.57 A\n",

-        "voltage across C=1.57 kV\n"

-       ]

-      }

-     ],

-     "prompt_number": 22

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Power_Electronics/Chapter5_4.ipynb b/_Power_Electronics/Chapter5_4.ipynb
deleted file mode 100755
index 1d261f20..00000000
--- a/_Power_Electronics/Chapter5_4.ipynb
+++ /dev/null
@@ -1,511 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 05 : Thyristor Commutation Techniques"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 5.1, Page No 252"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "L=5.0*10**-3            #mH\n",

-      "C=20.0*10**-6           #\u00b5F\n",

-      "V_s=200                 #V\n",

-      "\n",

-      "#Calculations\n",

-      "w_o=math.sqrt(1/(L*C))    #rad/s\n",

-      "t_o=math.pi/w_o           #ms\n",

-      "\n",

-      "#Results\n",

-      "print('conduction time of thyristor = %.2f ms' %(t_o*1000))\n",

-      "print('voltage across thyristor=%.0f V' %V_s)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "conduction time of thyristor = 0.99 ms\n",

-        "voltage across thyristor=200 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 12

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 5.2, Page No 255"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "C=20.0*10**-6         #\u00b5F\n",

-      "L=5.0*10**-6          #\u00b5H\n",

-      "V_s=230.0             #V\n",

-      "\n",

-      "#Calculations\n",

-      "I_p=V_s*math.sqrt(C/L)      #A\n",

-      "w_o=math.sqrt(1/(L*C))      #rad/sec\n",

-      "t_o=math.pi/w_o             #\u00b5S\n",

-      "I_o=300               \n",

-      "a = math.degrees(math.asin(I_o/(2*V_s)))   \n",

-      "V_ab = V_s*math.cos(math.radians(a))      #V \n",

-      "t_c=C*V_ab/I_o     #\u00b5s\n",

-      "\n",

-      "#Calculations\n",

-      "print(\"conduction time of auxillery thyristor=%.2f us\" %(t_o*10**6))\n",

-      "print(\"voltage across main thyristor=%.2f V\" %V_ab)\n",

-      "print(\"ckt turn off time=%.2f us\" %(t_c*10**6))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "conduction time of auxillery thyristor=31.42 us\n",

-        "voltage across main thyristor=174.36 V\n",

-        "ckt turn off time=11.62 us\n"

-       ]

-      }

-     ],

-     "prompt_number": 13

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 5.3 Page No 258"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "V_s=200.0           #V\n",

-      "R1=10.0             #\u2126\n",

-      "R2=100.0            #\u2126\n",

-      "C=0                 #  value of capacitor\n",

-      "\n",

-      "#Calculations\n",

-      "I1=V_s*(1/R1+2/R2)    #A\n",

-      "I2=V_s*(2/R1+1/R2)    #A\n",

-      "t_c1=40*10**-6\n",

-      "fos=2    #factor of safety\n",

-      "C1=t_c1*fos/(R1*math.log(2))\n",

-      "C2=t_c1*fos/(R2*math.log(2))\n",

-      "if C1 > C2 :\n",

-      "    C = C1*10**6\n",

-      "else :\n",

-      "    C = C2*10**6\n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"peak value of current through SCR1=%.2f A\" %I1); \n",

-      "print(\"Peak value of current through SCR2=%.2f A\" %I2);\n",

-      "print(\"Value of capacitor=%.2f uF\" %C);"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "peak value of current through SCR1=24.00 A\n",

-        "Peak value of current through SCR2=42.00 A\n",

-        "Value of capacitor=11.54 uF\n"

-       ]

-      }

-     ],

-     "prompt_number": 14

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 5.4, Page No 260"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0             #V\n",

-      "L=20*10**-6           #\u00b5H\n",

-      "C=40*10**-6           #\u00b5F\n",

-      "I_o=120.0             #A\n",

-      "\n",

-      "#Calculations\n",

-      "I_p=V_s*math.sqrt(C/L)   #A\n",

-      "t_c=C*V_s/I_o            #\u00b5s\n",

-      "w_o=math.sqrt(1/(L*C))  \n",

-      "t_c1=math.pi/(2*w_o)     #\u00b5s\n",

-      "\n",

-      "#Results\n",

-      "print(\"current through main thyristor=%.2f A\"  %(I_o+I_p))\n",

-      "print(\"Current through auxillery thyristor=%.2f A\" %I_o)\n",

-      "print(\"Circuit turn off time for main thyristor=%.2f us\" %(t_c*10**6))\n",

-      "print(\"Circuit turn off time for auxillery thyristor=%.2f us\" %(t_c1*10**6))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "current through main thyristor=445.27 A\n",

-        "Current through auxillery thyristor=120.00 A\n",

-        "Circuit turn off time for main thyristor=76.67 us\n",

-        "Circuit turn off time for auxillery thyristor=44.43 us\n"

-       ]

-      }

-     ],

-     "prompt_number": 15

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 5.5 Page No 263"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "C_j=25*10**-12      #pF\n",

-      "I_c=5*10**-3        #charging current\n",

-      "V_s=200.0           #V\n",

-      "R=50.0              #\u2126\n",

-      "\n",

-      "#Calculations\n",

-      "C=(C_j*V_s)/(I_c*R)\n",

-      "\n",

-      "\n",

-      "#RESULTS\n",

-      "print(\"Value of C=%.2f  \u00b5F\" %(C*10**6))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Value of C=0.02  \u00b5F\n"

-       ]

-      }

-     ],

-     "prompt_number": 16

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 5.6 Page No 263"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "V_s=200.0         #V\n",

-      "R=5.0             #\u2126\n",

-      "\n",

-      "#Calculations\n",

-      "C=10.0*10**-6\n",

-      "#for turn off V_s*(1-2*exp(-t/(R*C)))=0,    so after solving\n",

-      "t_c=R*C*math.log(2.0)\n",

-      "\n",

-      "#Results\n",

-      "print(\"circuit turn off time=%.2f us\" %(t_c*10**6))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "circuit turn off time=34.66 us\n"

-       ]

-      }

-     ],

-     "prompt_number": 17

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 5.7, Page No 264 "

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "R=1.0                   #\u2126\n",

-      "L=20*10**-6             #\u00b5H\n",

-      "C=40*10**-6             #\u00b5F\n",

-      "\n",

-      "#Calculations\n",

-      "w_r=math.sqrt((1/(L*C))-(R/(2*L))**2)\n",

-      "t_1=math.pi/w_r\n",

-      "\n",

-      "#Results\n",

-      "print(\"conduction time of thyristor=%.3f us\" %(t_1*10**6))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "conduction time of thyristor=125.664 us\n"

-       ]

-      }

-     ],

-     "prompt_number": 18

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 5.8 Page No 265"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math \n",

-      "\n",

-      "#initialisation of variables\n",

-      "dv=400*10.0**-6       #dv=dv_T/dt(V/s)\n",

-      "V_s=200.0             #v\n",

-      "R=20.0                #\u2126\n",

-      "\n",

-      "#Calculations\n",

-      "C=V_s/(R*dv)         \n",

-      "C_j=.025*10**-12\n",

-      "C_s=C-C_j\n",

-      "I_T=40;\n",

-      "R_s=1/((I_T/V_s)-(1/R)) \n",

-      "#value of R_s in book is wrongly calculated\n",

-      "\n",

-      "#Results\n",

-      "print(\"R_s=%.2f ohm\" %R_s)\n",

-      "print(\"C_s=%.3f uF\" %(C_s/10**6))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "R_s=6.67 ohm\n",

-        "C_s=0.025 uF\n"

-       ]

-      }

-     ],

-     "prompt_number": 19

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 5.9 Page No 265"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=200.0          #V\n",

-      "C=20.0*10**-6      #\u00b5H   \n",

-      "L=0.2*10**-3       #\u00b5F\n",

-      "i_c=10.0\n",

-      "\n",

-      "#Calculations\n",

-      "i=V_s*math.sqrt(C/L)\n",

-      "w_o=1.0/math.sqrt(L*C)\n",

-      "t_1 = (1/w_o)*math.degrees(math.asin(i_c/i))\n",

-      "t_o=math.pi/w_o\n",

-      "t_c=t_o-2*t_1    \n",

-      "\n",

-      "#Results\n",

-      "print(\"reqd time=%.2f us\" %(t_1*10**6))\n",

-      "print(\"ckt turn off time=%.2f us\" %(t_c*10**6))\n",

-      "print(\"ckt turn off time=%.5f us\" %t_1)\n",

-      "#solution in book wrong, as wrong values are selected while filling the formuleas"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "reqd time=575.37 us\n",

-        "ckt turn off time=-952.05 us\n",

-        "ckt turn off time=0.00058 us\n"

-       ]

-      }

-     ],

-     "prompt_number": 20

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 5.11 Page No 268 "

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "L=1.0              #\u00b5H\n",

-      "R=50.0             #\u2126\n",

-      "V_s=200.0          #V\n",

-      "t=0.01             #sec\n",

-      "Vd=0.7\n",

-      "\n",

-      "#Calculations\n",

-      "tau=L/R\n",

-      "i=(V_s/R)*(1-math.exp(-t/tau))\n",

-      "t=8*10**-3\n",

-      "i1=i-t*Vd  \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"current through L = %.2f A\" %i1)\n",

-      "i_R=0                  #current in R at t=.008s\n",

-      "print(\"Current through R = %.2f A\" %i_R)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "current through L = 1.57 A\n",

-        "Current through R = 0.00 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 21

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 5.12, Page No 269"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "\n",

-      "#initialisation of variables\n",

-      "\n",

-      "#initialisation of variables\n",

-      "L=1.0                      #H\n",

-      "R=50.0                   #ohm\n",

-      "V_s=200.0                #V\n",

-      "\n",

-      "#Calculations\n",

-      "tau=L/R\n",

-      "t=0.01                 #s\n",

-      "i=(V_s/R)*(1-math.exp(-t/tau))\n",

-      "C=1*10**-6            #F\n",

-      "V_c=math.sqrt(L/C)*i\n",

-      "\n",

-      "#Results\n",

-      "print(\"current in R,L=%.2f A\" %i)\n",

-      "print(\"voltage across C=%.2f kV\" %(V_c/1000))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "current in R,L=1.57 A\n",

-        "voltage across C=1.57 kV\n"

-       ]

-      }

-     ],

-     "prompt_number": 22

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Power_Electronics/Chapter6.ipynb b/_Power_Electronics/Chapter6.ipynb
deleted file mode 100755
index dff6564b..00000000
--- a/_Power_Electronics/Chapter6.ipynb
+++ /dev/null
@@ -1,1761 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 06 : Phase Controlled Rectifiers"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.1, Page No 283"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=230.0\n",

-      "P=1000.0\n",

-      "R=V**2/P\n",

-      "\n",

-      "#Calculations\n",

-      "a=math.pi/4\n",

-      "V_or1=(math.sqrt(2)*V/(2*math.sqrt(math.pi)))*math.sqrt((math.pi-a)+.5*math.sin(2*a))\n",

-      "P1=V_or1**2/R    \n",

-      "a=math.pi/2\n",

-      "V_or2=(math.sqrt(2)*V/(2*math.sqrt(math.pi)))*math.sqrt((math.pi-a)+.5*math.sin(2*a))\n",

-      "P2=V_or2**2/R   \n",

-      "\n",

-      "#Results\n",

-      "print(\"when firing angle delay is of 45deg\")\n",

-      "print(\"power absorbed=%.2f W\" %P1)\n",

-      "print(\"when firing angle delay is of 90deg\")\n",

-      "print(\"power absorbed=%.2f W\" %P2)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "when firing angle delay is of 45deg\n",

-        "power absorbed=454.58 W\n",

-        "when firing angle delay is of 90deg\n",

-        "power absorbed=250.00 W\n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.2, Page No 283"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=230.0\n",

-      "E=150.0\n",

-      "R=8.0\n",

-      "\n",

-      "#Calculations\n",

-      "th1=math.sin(math.radians(E/(math.sqrt(2)*V)))\n",

-      "I_o=(1/(2*math.pi*R))*(2*math.sqrt(2)*230*math.cos(math.radians(th1))-E*(math.pi-2*th1*math.pi/180))    \n",

-      "P=E*I_o    \n",

-      "I_or=math.sqrt((1/(2*math.pi*R**2))*((V**2+E**2)*(math.pi-2*th1*math.pi/180)+V**2*math.sin(math.radians(2*th1))-4*math.sqrt(2)*V*E*math.cos(math.radians(th1))))\n",

-      "P_r=I_or**2*R    \n",

-      "pf=(P+P_r)/(V*I_or)\n",

-      "\n",

-      "#Results\n",

-      "print(\"avg charging curent=%.4f A\" %I_o)\n",

-      "print(\"power supplied to the battery=%.2f W\" %P)\n",

-      "print(\"power dissipated by the resistor=%.3f W\" %P_r)    \n",

-      "print(\"supply pf=%.3f\" %pf)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "avg charging curent=3.5679 A\n",

-        "power supplied to the battery=535.18 W\n",

-        "power dissipated by the resistor=829.760 W\n",

-        "supply pf=0.583\n"

-       ]

-      }

-     ],

-     "prompt_number": 2

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.3 Page No 284"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=230.0\n",

-      "E=150.0\n",

-      "R=8.0\n",

-      "a=35.0\n",

-      "\n",

-      "#Calculations\n",

-      "th1=math.degrees(math.asin(E/(math.sqrt(2)*V)))\n",

-      "th2=180-th1\n",

-      "I_o=(1/(2*math.pi*R))*(math.sqrt(2)*230*(math.cos(math.radians(a))-math.cos(math.radians(th2)))-E*((th2-a)*math.pi/180))    \n",

-      "P=E*I_o    \n",

-      "I_or=math.sqrt((1/(2*math.pi*R**2))*((V**2+E**2)*((th2-a)*math.pi/180)-(V**2/2)*(math.sin(math.radians(2*th2))-math.sin(math.radians(2*a)))-2*math.sqrt(2)*V*E*(math.cos(math.radians(a))-math.cos(math.radians(th2)))))\n",

-      "P_r=I_or**2*R    \n",

-      "pf=(P+P_r)/(V*I_or)    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"avg charging curent=%.4f A\" %I_o)\n",

-      "print(\"power supplied to the battery=%.2f W\" %P)\n",

-      "print(\"power dissipated by the resistor=%.2f W\" %P_r)\n",

-      "print(\"supply pf=%.4f\" %pf)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "avg charging curent=4.9208 A\n",

-        "power supplied to the battery=738.12 W\n",

-        "power dissipated by the resistor=689.54 W\n",

-        "supply pf=0.6686\n"

-       ]

-      }

-     ],

-     "prompt_number": 3

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.4, Page No 285"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "B=210\n",

-      "f=50.0     #Hz\n",

-      "w=2*math.pi*f\n",

-      "a=40.0     #firing angle\n",

-      "V=230.0\n",

-      "R=5.0\n",

-      "L=2*10**-3\n",

-      "\n",

-      "#Calculations\n",

-      "t_c1=(360-B)*math.pi/(180*w)   \n",

-      "V_o1=(math.sqrt(2)*230/(2*math.pi))*(math.cos(math.radians(a))-math.cos(math.radians(B)))    \n",

-      "I_o1=V_o1/R    \n",

-      "E=110\n",

-      "R=5\n",

-      "L=2*10**-3\n",

-      "th1=math.degrees(math.asin(E/(math.sqrt(2)*V)))\n",

-      "t_c2=(360-B+th1)*math.pi/(180*w)    \n",

-      "V_o2=(math.sqrt(2)*230/(2*math.pi))*(math.cos(math.radians(a))-math.cos(math.radians(B)))    \n",

-      "I_o2=(1/(2*math.pi*R))*(math.sqrt(2)*230*(math.cos(math.radians(a))-math.cos(math.radians(B)))-E*((B-a)*math.pi/180))   \n",

-      "V_o2=R*I_o2+E    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"for R=5ohm and L=2mH\")\n",

-      "print(\"ckt turn off time=%.3f msec\" %(t_c1*1000))\n",

-      "print(\"avg output voltage=%.3f V\" %V_o1)\n",

-      "print(\"avg output current=%.4f A\" %I_o1)\n",

-      "print(\"for R=5ohm % L=2mH and E=110V\")\n",

-      "print(\"ckt turn off time=%.3f msec\" %(t_c2*1000))\n",

-      "print(\"avg output current=%.4f A\" %I_o2)\n",

-      "print(\"avg output voltage=%.3f V\" %V_o2)   "

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for R=5ohm and L=2mH\n",

-        "ckt turn off time=8.333 msec\n",

-        "avg output voltage=84.489 V\n",

-        "avg output current=16.8979 A\n",

-        "for R=5ohm % L=2mH and E=110V\n",

-        "ckt turn off time=9.431 msec\n",

-        "avg output current=6.5090 A\n",

-        "avg output voltage=142.545 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 4

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.5 Page No 286"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "f=50.0\n",

-      "R=10.0\n",

-      "a=60.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_m=(math.sqrt(2)*V_s)\n",

-      "V_o=V_m/(2*math.pi)*(1+math.cos(math.radians(a)))\n",

-      "I_o=V_o/R\n",

-      "V_or=(V_m/(2*math.sqrt(math.pi)))*math.sqrt((math.pi-a*math.pi/180)+.5*math.sin(math.radians(2*a)))\n",

-      "I_or=V_or/R\n",

-      "P_dc=V_o*I_o\n",

-      "P_ac=V_or*I_or\n",

-      "RE=P_dc/P_ac    \n",

-      "FF=V_or/V_o    \n",

-      "VRF=math.sqrt(FF**2-1)    \n",

-      "TUF=P_dc/(V_s*I_or)    \n",

-      "PIV=V_m    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"rectification efficiency=%.4f\" %RE)\n",

-      "print(\"form factor=%.3f\" %FF)\n",

-      "print(\"voltage ripple factor=%.4f\" %VRF)\n",

-      "print(\"t/f utilisation factor=%.4f\" %TUF)\n",

-      "print(\"PIV of thyristor=%.2f V\" %PIV)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rectification efficiency=0.2834\n",

-        "form factor=1.879\n",

-        "voltage ripple factor=1.5903\n",

-        "t/f utilisation factor=0.1797\n",

-        "PIV of thyristor=325.27 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 5

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.6 Page No 294"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=1000.0\n",

-      "fos=2.5     #factor of safety\n",

-      "I_TAV=40.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_m1=V/(2*fos)\n",

-      "P1=(2*V_m1/math.pi)*I_TAV    \n",

-      "V_m2=V/(fos)\n",

-      "P2=(2*V_m2/math.pi)*I_TAV    \n",

-      "\n",

-      "#Results\n",

-      "print(\"for mid pt convertor\")\n",

-      "print(\"power handled=%.3f kW\" %(P1/1000))\n",

-      "print(\"for bridge convertor\")\n",

-      "print(\"power handled=%.3f kW\" %(P2/1000))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for mid pt convertor\n",

-        "power handled=5.093 kW\n",

-        "for bridge convertor\n",

-        "power handled=10.186 kW\n"

-       ]

-      }

-     ],

-     "prompt_number": 6

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.7, Page No 297"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "R=.4\n",

-      "I_o=10\n",

-      "I_or=I_o\n",

-      "E=120.0\n",

-      "\n",

-      "#Calculations\n",

-      "a1=math.degrees(math.acos((E+I_o*R)*math.pi/(2*V_m)))\n",

-      "pf1=(E*I_o+I_or**2*R)/(V_s*I_or)    \n",

-      "E=-120.0\n",

-      "a2=math.degrees(math.acos((E+I_o*R)*math.pi/(2*V_m))) \n",

-      "pf2=(-E*I_o-I_or**2*R)/(V_s*I_or)   \n",

-      "\n",

-      "#Results\n",

-      "print(\"firing angle delay=%.2f deg\" %a1)\n",

-      "print(\"pf=%.4f\" %pf1)\n",

-      "print(\"firing angle delay=%.2f deg\" %a2)\n",

-      "print(\"pf=%.4f\" %pf2)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "firing angle delay=53.21 deg\n",

-        "pf=0.5391\n",

-        "firing angle delay=124.07 deg\n",

-        "pf=0.5043\n"

-       ]

-      }

-     ],

-     "prompt_number": 7

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.9 Page No 299"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "f=50.0\n",

-      "a=45.0\n",

-      "R=5.0\n",

-      "E=100.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_o=((math.sqrt(2)*V_s)/(2*math.pi))*(3+math.cos(math.radians(a)))\n",

-      "I_o=(V_o-E)/R    \n",

-      "P=E*I_o    \n",

-      "\n",

-      "#Results\n",

-      "print(\"avg o/p current=%.3f A\" %I_o)\n",

-      "print(\"power delivered to battery=%.4f kW\" %(P/1000))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "avg o/p current=18.382 A\n",

-        "power delivered to battery=1.8382 kW\n"

-       ]

-      }

-     ],

-     "prompt_number": 8

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.10 Page No 300"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variablesV_s=230\n",

-      "f=50.0\n",

-      "a=50.0\n",

-      "R=6.0\n",

-      "E=60.0\n",

-      "V_o1=((math.sqrt(2)*2*V_s)/(math.pi))*math.cos(math.radians(a))\n",

-      "I_o1=(V_o1-E)/R    \n",

-      "\n",

-      "#ATQ after applying the conditions\n",

-      "V_o2=((math.sqrt(2)*V_s)/(math.pi))*math.cos(math.radians(a))\n",

-      "I_o2=(V_o2-E)/R    \n",

-      "\n",

-      "print(\"avg o/p current=%.3f A\" %I_o1)\n",

-      "print(\"avg o/p current after change=%.2f A\" %I_o2)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "avg o/p current=12.184 A\n",

-        "avg o/p current after change=1.09 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 9

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.11 Page No 309"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "a=45.0\n",

-      "R=10.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_o=(2*V_m/math.pi)*math.cos(math.radians(a))\n",

-      "I_o=V_o/R\n",

-      "V_or=V_m/math.sqrt(2)\n",

-      "I_or=I_o\n",

-      "P_dc=V_o*I_o\n",

-      "P_ac=V_or*I_or\n",

-      "RE=P_dc/P_ac    \n",

-      "FF=V_or/V_o    \n",

-      "VRF=math.sqrt(FF**2-1)    \n",

-      "I_s1=2*math.sqrt(2)*I_o/math.pi\n",

-      "DF=math.cos(math.radians(a))\n",

-      "CDF=.90032\n",

-      "pf=CDF*DF    \n",

-      "HF=math.sqrt((1/CDF**2)-1)    \n",

-      "Q=2*V_m*I_o*math.sin(math.radians(a))/math.pi \n",

-      "\n",

-      "#Results\n",

-      "print(\"rectification efficiency=%.4f\" %RE)\n",

-      "print(\"form factor=%.4f\" %FF)\n",

-      "print(\"voltage ripple factor=%.4f\" %VRF)\n",

-      "print(\"pf=%.5f\" %pf)\n",

-      "print(\"HF=%.5f\" %HF)\n",

-      "print(\"active power=%.2f W\" %P_dc)   \n",

-      "print(\"reactive power=%.3f Var\" %Q)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rectification efficiency=0.6366\n",

-        "form factor=1.5708\n",

-        "voltage ripple factor=1.2114\n",

-        "pf=0.63662\n",

-        "HF=0.48342\n",

-        "active power=2143.96 W\n",

-        "reactive power=2143.956 Var\n"

-       ]

-      }

-     ],

-     "prompt_number": 10

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.12, Page No 310"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "a=45.0\n",

-      "R=10.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_o=(V_m/math.pi)*(1+math.cos(math.radians(a)))\n",

-      "I_o=V_o/R\n",

-      "V_or=V_s*math.sqrt((1/math.pi)*((math.pi-a*math.pi/180)+math.sin(math.radians(2*a))/2))\n",

-      "I_or=I_o\n",

-      "P_dc=V_o*I_o\n",

-      "P_ac=V_or*I_or\n",

-      "RE=P_dc/P_ac    \n",

-      "FF=V_or/V_o    \n",

-      "VRF=math.sqrt(FF**2-1)    \n",

-      "I_s1=2*math.sqrt(2)*I_o*math.cos(math.radians(a/2))/math.pi\n",

-      "DF=math.cos(math.radians(a/2))   \n",

-      "CDF=2*math.sqrt(2)*math.cos(math.radians(a/2))/math.sqrt(math.pi*(math.pi-a*math.pi/180))    \n",

-      "pf=CDF*DF    \n",

-      "HF=math.sqrt((1/CDF**2)-1)    \n",

-      "Q=V_m*I_o*math.sin(math.radians(a))/math.pi\n",

-      "\n",

-      "#Results\n",

-      "print(\"form factor=%.3f\" %FF)\n",

-      "print(\"rectification efficiency=%.4f\" %RE)\n",

-      "print(\"voltage ripple factor=%.3f\" %VRF)    \n",

-      "print(\"DF=%.4f\" %DF)\n",

-      "print(\"CDF=%.4f\" %CDF)\n",

-      "print(\"pf=%.4f\" %pf)\n",

-      "print(\"HF=%.4f\" %HF)\n",

-      "print(\"active power=%.3f W\" %P_dc)\n",

-      "print(\"reactive power=%.2f Var\" %Q)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "form factor=1.241\n",

-        "rectification efficiency=0.8059\n",

-        "voltage ripple factor=0.735\n",

-        "DF=0.9239\n",

-        "CDF=0.9605\n",

-        "pf=0.8874\n",

-        "HF=0.2899\n",

-        "active power=3123.973 W\n",

-        "reactive power=1293.99 Var\n"

-       ]

-      }

-     ],

-     "prompt_number": 11

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.13, Page No 319"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "R=10.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_ml=math.sqrt(2)*V_s\n",

-      "V_om=3*V_ml/(2*math.pi)\n",

-      "V_o=V_om/2\n",

-      "th=30\n",

-      "a=math.degrees(math.acos((2*math.pi*math.sqrt(3)*V_o/(3*V_ml)-1)))-th    \n",

-      "I_o=V_o/R    \n",

-      "V_or=V_ml/(2*math.sqrt(math.pi))*math.sqrt((5*math.pi/6-a*math.pi/180)+.5*math.sin(math.radians(2*a+2*th)))\n",

-      "I_or=V_or/R    \n",

-      "RE=V_o*I_o/(V_or*I_or)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"delay angle=%.1f deg\" %a)\n",

-      "print(\"avg load current=%.3f A\" %I_o)\n",

-      "print(\"rms load current=%.3f A\" %I_or)\n",

-      "print(\"rectification efficiency=%.4f\" %RE)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "delay angle=67.7 deg\n",

-        "avg load current=7.765 A\n",

-        "rms load current=10.477 A\n",

-        "rectification efficiency=0.5494\n"

-       ]

-      }

-     ],

-     "prompt_number": 12

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.15, Page No 321"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=400.0\n",

-      "V_ml=math.sqrt(2)*V\n",

-      "v_T=1.4\n",

-      "a1=30.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_o1=3*V_ml/(2*math.pi)*math.cos(math.radians(a1))-v_T   \n",

-      "a2=60.0\n",

-      "V_o2=3*V_ml/(2*math.pi)*math.cos(math.radians(a2))-v_T  \n",

-      "I_o=36\n",

-      "I_TA=I_o/3    \n",

-      "I_Tr=I_o/math.sqrt(3)    \n",

-      "P=I_TA*v_T       \n",

-      "\n",

-      "#Results\n",

-      "print(\"for firing angle = 30deg\")\n",

-      "print(\"avg output voltage=%.3f V\" %V_o1)\n",

-      "print(\"for firing angle = 60deg\")\n",

-      "print(\"avg output voltage=%.2f V\" %V_o2)\n",

-      "print(\"avg current rating=%.0f A\" %I_TA)\n",

-      "print(\"rms current rating=%.3f A\" %I_Tr)\n",

-      "print(\"PIV of SCR=%.1f V\" %V_ml)\n",

-      "print(\"power dissipated=%.1f W\" %P)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for firing angle = 30deg\n",

-        "avg output voltage=232.509 V\n",

-        "for firing angle = 60deg\n",

-        "avg output voltage=133.65 V\n",

-        "avg current rating=12 A\n",

-        "rms current rating=20.785 A\n",

-        "PIV of SCR=565.7 V\n",

-        "power dissipated=16.8 W\n"

-       ]

-      }

-     ],

-     "prompt_number": 13

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.17, Page No 331"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "E=200\n",

-      "I_o=20\n",

-      "R=.5\n",

-      "\n",

-      "#Calculations\n",

-      "V_o1=E+I_o*R\n",

-      "V_s=230\n",

-      "V_ml=math.sqrt(2)*V_s\n",

-      "a1=math.degrees(math.acos(V_o1*math.pi/(3*V_ml)))\n",

-      "th=120\n",

-      "I_s=math.sqrt((1/math.pi)*I_o**2*th*math.pi/180)\n",

-      "P=E*I_o+I_o**2*R\n",

-      "pf=P/(math.sqrt(3)*V_s*I_s)    \n",

-      "V_o2=E-I_o*R\n",

-      "a2=math.degrees(math.acos(-V_o2*math.pi/(3*V_ml))) \n",

-      "\n",

-      "#Results\n",

-      "print(\"firing angle delay=%.3f deg\" %a1)\n",

-      "print(\"pf=%.3f\" %pf)\n",

-      "print(\"firing angle delay=%.2f deg\" %a2)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "firing angle delay=47.461 deg\n",

-        "pf=0.646\n",

-        "firing angle delay=127.71 deg\n"

-       ]

-      }

-     ],

-     "prompt_number": 14

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.18, Page No 332"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=230.0\n",

-      "f=50.0\n",

-      "\n",

-      "#Calculations\n",

-      "w=2*math.pi*f\n",

-      "a1=0\n",

-      "t_c1=(4*math.pi/3-a1*math.pi/180)/w    \n",

-      "a2=30\n",

-      "t_c2=(4*math.pi/3-a2*math.pi/180)/w    \n",

-      "\n",

-      "#Results\n",

-      "print(\"for firing angle delay=0deg\")\n",

-      "print(\"commutation time=%.2f ms\" %(t_c1*1000))\n",

-      "print(\"peak reverse voltage=%.2f V\" %(math.sqrt(2)*V))\n",

-      "print(\"for firing angle delay=30deg\")\n",

-      "print(\"commutation time=%.2f ms\" %(t_c2*1000))\n",

-      "print(\"peak reverse voltage=%.2f V\" %(math.sqrt(2)*V))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for firing angle delay=0deg\n",

-        "commutation time=13.33 ms\n",

-        "peak reverse voltage=325.27 V\n",

-        "for firing angle delay=30deg\n",

-        "commutation time=11.67 ms\n",

-        "peak reverse voltage=325.27 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 15

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.19, Page No 333"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "a=30.0\n",

-      "R=10.0\n",

-      "P=5000.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_s=math.sqrt(P*R*2*math.pi/(2*3)/(math.pi/3+math.sqrt(3)*math.cos(math.radians(2*a))/2))\n",

-      "V_ph=V_s/math.sqrt(3)    \n",

-      "I_or=math.sqrt(P*R)\n",

-      "V_s=I_or*math.pi/(math.sqrt(2)*3*math.cos(math.radians(a)))\n",

-      "V_ph=V_s/math.sqrt(3) \n",

-      "\n",

-      "#Results\n",

-      "print(\"per phase voltage percent V_ph=%.3f V\" %V_ph)   \n",

-      "print(\"for constant load current\")\n",

-      "print(\"V_ph=%.2f V\" %V_ph)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "per phase voltage percent V_ph=110.384 V\n",

-        "for constant load current\n",

-        "V_ph=110.38 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 16

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.20, Page No 334"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "a=30.0\n",

-      "R=10.0\n",

-      "P=5000.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_s=math.sqrt(P*R*4*math.pi/(2*3)/(2*math.pi/3+math.sqrt(3)*(1+math.cos(math.radians(2*a)))/2))\n",

-      "V_ph=V_s/math.sqrt(3)    \n",

-      "I_or=math.sqrt(P*R)\n",

-      "V_s=I_or*2*math.pi/(math.sqrt(2)*3*(1+math.cos(math.radians(a))))\n",

-      "V_ph=V_s/math.sqrt(3)   \n",

-      "\n",

-      "#Results\n",

-      "print(\"per phase voltage percent V_ph=%.3f V\" %V_ph) \n",

-      "print(\"for constant load current\")\n",

-      "print(\"V_ph=%.2f V\" %V_ph)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "per phase voltage percent V_ph=102.459 V\n",

-        "for constant load current\n",

-        "V_ph=102.46 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 17

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.21, Page No 334"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "a=90.0\n",

-      "R=10.0\n",

-      "P=5000.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_s=math.sqrt(P*R*4*math.pi/(2*3)/((math.pi-math.pi/2)+(math.sin(math.radians(2*a)))/2))\n",

-      "V_ph=V_s/math.sqrt(3)    \n",

-      "I_or=math.sqrt(P*R)\n",

-      "V_s=I_or*2*math.pi/(math.sqrt(2)*3*(1+math.cos(math.radians(a))))\n",

-      "V_ph=V_s/math.sqrt(3)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"per phase voltage percent V_ph=%.2f V\" %V_ph)\n",

-      "print(\"for constant load current\")\n",

-      "print(\"V_ph=%.1f V\" %V_ph)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "per phase voltage percent V_ph=191.19 V\n",

-        "for constant load current\n",

-        "V_ph=191.2 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 18

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.22 Page No 334"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "E=200.0\n",

-      "I_o=20.0\n",

-      "R=.5\n",

-      "\n",

-      "#Calculations\n",

-      "V_o=E+I_o*R\n",

-      "V_s=230\n",

-      "V_ml=math.sqrt(2)*V_s\n",

-      "a=math.degrees(math.acos(V_o*2*math.pi/(3*V_ml)-1))  \n",

-      "a1=180-a\n",

-      "I_sr=math.sqrt((1/math.pi)*I_o**2*(a1*math.pi/180))\n",

-      "P=V_o*I_o\n",

-      "pf=P/(math.sqrt(3)*V_s*I_sr)   \n",

-      "\n",

-      "#Results\n",

-      "print(\"firing angle delay=%.2f deg\" %a)\n",

-      "print(\"pf=%.2f\" %pf)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "firing angle delay=69.38 deg\n",

-        "pf=0.67\n"

-       ]

-      }

-     ],

-     "prompt_number": 19

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.23, Page No 335"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=400.0\n",

-      "f=50.0\n",

-      "I_o=15.0\n",

-      "a=45.0\n",

-      "\n",

-      "#Calculations\n",

-      "I_TA=I_o*120.0/360.0\n",

-      "I_Tr=math.sqrt(I_o**2*120/360)\n",

-      "I_sr=math.sqrt(I_o**2*120/180)\n",

-      "V_ml=math.sqrt(2)*V_s\n",

-      "V_o=3*V_ml*math.cos(math.radians(a))/math.pi\n",

-      "V_or=V_ml*math.sqrt((3/(2*math.pi))*(math.pi/3+math.sqrt(3/2)*math.cos(math.radians(2*a))))\n",

-      "I_or=I_o\n",

-      "P_dc=V_o*I_o\n",

-      "P_ac=V_or*I_or\n",

-      "RE=P_dc/P_ac    \n",

-      "VA=3*V_s/math.sqrt(3)*I_sr\n",

-      "TUF=P_dc/VA    \n",

-      "pf=P_ac/VA    \n",

-      "\n",

-      "#Results\n",

-      "print(\"rectification efficiency=%.5f\" %RE)\n",

-      "print(\"TUF=%.4f\" %TUF)\n",

-      "print(\"Input pf=%.3f\" %pf)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rectification efficiency=0.95493\n",

-        "TUF=0.6752\n",

-        "Input pf=0.707\n"

-       ]

-      }

-     ],

-     "prompt_number": 20

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.24, Page No 341"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "I=10.0\n",

-      "a=45.0\n",

-      "V=400.0\n",

-      "f=50.0\n",

-      "\n",

-      "#Calculations\n",

-      "DF=math.cos(math.radians(a))\n",

-      "I_o=10\n",

-      "I_s1=4*I_o/(math.sqrt(2)*math.pi)*math.sin(math.pi/3)\n",

-      "I_sr=I_o*math.sqrt(2.0/3.0)\n",

-      "I_o=1     #suppose\n",

-      "CDF=I_s1/I_sr    \n",

-      "THD=math.sqrt(1/CDF**2-1)    \n",

-      "pf=CDF*DF    \n",

-      "P=(3*math.sqrt(2)*V*math.cos(math.radians(a))/math.pi)*I\n",

-      "Q=(3*math.sqrt(2)*V*math.sin(math.radians(a))/math.pi)*I  \n",

-      "   \n",

-      "#Results\n",

-      "print(\"DF=%.3f\" %DF)\n",

-      "print(\"CDF=%.3f\" %CDF)\n",

-      "print(\"THD=%.5f\" %THD)\n",

-      "print(\"PF=%.4f\" %pf)\n",

-      "print(\"active power=%.2f W\" %P)  \n",

-      "print(\"reactive power=%.2f Var\" %Q)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "DF=0.707\n",

-        "CDF=0.955\n",

-        "THD=0.31084\n",

-        "PF=0.6752\n",

-        "active power=3819.72 W\n",

-        "reactive power=3819.72 Var\n"

-       ]

-      }

-     ],

-     "prompt_number": 21

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.25, Page No 342"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "print(\"for firing angle=30deg\")\n",

-      "a=30.0\n",

-      "V=400.0\n",

-      "V_ml=math.sqrt(2)*V\n",

-      "V_o=3*V_ml*math.cos(math.radians(a))/math.pi\n",

-      "E=350\n",

-      "R=10\n",

-      "\n",

-      "#Calculations\n",

-      "I_o=(V_o-E)/R\n",

-      "I_or=I_o\n",

-      "P1=V_o*I_o    \n",

-      "I_sr=I_o*math.sqrt(2.0/3.0)\n",

-      "VA=3*V/math.sqrt(3)*I_sr\n",

-      "pf=P1/VA \n",

-      "a=180-60\n",

-      "V=400\n",

-      "V_ml=math.sqrt(2)*V\n",

-      "V_o=3*V_ml*math.cos(math.radians(a))/math.pi\n",

-      "E=-350\n",

-      "R=10\n",

-      "I_o=(V_o-E)/R\n",

-      "I_or=I_o\n",

-      "P2=-V_o*I_o    \n",

-      "I_sr=I_o*math.sqrt(2.0/3.0)\n",

-      "VA=3*V/math.sqrt(3)*I_sr\n",

-      "pf=P2/VA       \n",

-      "\n",

-      "print(\"power delivered to load=%.2f W\" %P1)\n",

-      "print(\"pf=%.4f\" %pf)\n",

-      "print(\"for firing advance angle=60deg\")\n",

-      "print(\"power delivered to load=%.2f W\" %P2)\n",

-      "print(\"pf=%.4f\" %pf)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits.\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for firing angle=30deg\n",

-        "power delivered to load=5511.74 W\n",

-        "pf=0.4775\n",

-        "for firing advance angle=60deg\n",

-        "power delivered to load=2158.20 W\n",

-        "pf=0.4775\n"

-       ]

-      }

-     ],

-     "prompt_number": 22

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.26, Page No 347"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "a=0\n",

-      "u=15.0\n",

-      "\n",

-      "#Calculations\n",

-      "i=math.cos(math.radians(a))-math.cos(math.radians(a+u))\n",

-      "a=30\n",

-      "u=math.degrees(math.acos(math.cos(math.radians(a))-i))-a  \n",

-      "a=45\n",

-      "u=math.degrees(math.acos(math.cos(math.radians(a))-i))-a    \n",

-      "a=60\n",

-      "u=math.degrees(math.acos(math.cos(math.radians(a))-i))-a  \n",

-      "\n",

-      "#Results\n",

-      "print(\"for firing angle=30deg\") \n",

-      "print(\"overlap angle=%.1f deg\" %u)\n",

-      "print(\"for firing angle=45deg\")  \n",

-      "print(\"overlap angle=%.1f deg\" %u)\n",

-      "print(\"for firing angle=60deg\") \n",

-      "print(\"overlap angle=%.2f deg\" %u)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for firing angle=30deg\n",

-        "overlap angle=2.2 deg\n",

-        "for firing angle=45deg\n",

-        "overlap angle=2.2 deg\n",

-        "for firing angle=60deg\n",

-        "overlap angle=2.23 deg\n"

-       ]

-      }

-     ],

-     "prompt_number": 23

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.28, Page No 352"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "E=400.0\n",

-      "I_o=20.0\n",

-      "R=1\n",

-      "\n",

-      "#Calculations\n",

-      "V_o=E+I_o*R\n",

-      "f=50.0\n",

-      "w=2*math.pi*f\n",

-      "L=.004\n",

-      "V=230 #per phase voltage\n",

-      "V_ml=math.sqrt(6)*V\n",

-      "a=math.degrees(math.acos(math.pi/(3*V_ml)*(V_o+3*w*L*I_o/math.pi)))   \n",

-      "print(\"firing angle delay=%.3f deg\" %a)\n",

-      "u=math.degrees(math.acos(math.pi/(3*V_ml)*(V_o-3*w*L*I_o/math.pi)))-a    \n",

-      "\n",

-      "#Results\n",

-      "print(\"overlap angle=%.2f deg\" %u)\n",

-      "#Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "firing angle delay=34.382 deg\n",

-        "overlap angle=8.22 deg\n"

-       ]

-      }

-     ],

-     "prompt_number": 24

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.29, Page No 352"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=400.0\n",

-      "f=50.0\n",

-      "w=2*math.pi*f\n",

-      "R=1\n",

-      "E=230\n",

-      "I=15.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_o=-E+I*R\n",

-      "V_ml=math.sqrt(2)*V\n",

-      "a=math.degrees(math.acos(V_o*2*math.pi/(3*V_ml)))  \n",

-      "L=0.004\n",

-      "a=math.degrees(math.acos((2*math.pi)/(3*V_ml)*(V_o+3*w*L*I/(2*math.pi))))  \n",

-      "u=math.degrees(math.acos(math.cos(math.radians(a))-3*f*L*I/V_ml))-a    \n",

-      "\n",

-      "#Results\n",

-      "print(\"firing angle=%.3f deg\" %a)\n",

-      "print(\"firing angle delay=%.3f deg\" %a)\n",

-      "print(\"overlap angle=%.3f deg\" %u)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits.\n",

-      " \n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "firing angle=139.702 deg\n",

-        "firing angle delay=139.702 deg\n",

-        "overlap angle=1.431 deg\n"

-       ]

-      }

-     ],

-     "prompt_number": 25

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.31, Page No 361"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=230.0 #per phase\n",

-      "f=50.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_ml=math.sqrt(3.0)*math.sqrt(2)*V\n",

-      "w=2*math.pi*f\n",

-      "a1=60.0\n",

-      "L=0.015\n",

-      "i_cp=(math.sqrt(3)*V_ml/(w*L))*(1-math.sin(math.radians(a1)))    \n",

-      "\n",

-      "#Results\n",

-      "print(\"circulating current=%.4f A\" %i_cp)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "circulating current=27.7425 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 26

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.32, Page No 362"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=230.0\n",

-      "V_m=math.sqrt(2)*V\n",

-      "a=30.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_o=2*V_m* math.cos(math.radians(a))/math.pi    \n",

-      "R=10\n",

-      "I_o=V_o/R    \n",

-      "I_TA=I_o*math.pi/(2*math.pi)    \n",

-      "I_Tr=math.sqrt(I_o**2*math.pi/(2*math.pi))    \n",

-      "I_s=math.sqrt(I_o**2*math.pi/(math.pi)) \n",

-      "I_o=I_s\n",

-      "pf=(V_o*I_o/(V*I_s))    \n",

-      "\n",

-      "#Results\n",

-      "print(\"avg o/p voltage=%.3f V\" %V_o)\n",

-      "print(\"avg o/p current=%.2f A\" %I_o)\n",

-      "print(\"avg value of thyristor current=%.3f A\" %I_TA)\n",

-      "print(\"rms value of thyristor current=%.2f A\" %I_Tr)\n",

-      "print(\"pf=%.4f\" %pf)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits.\n",

-      " \n",

-      " \n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "avg o/p voltage=179.330 V\n",

-        "avg o/p current=17.93 A\n",

-        "avg value of thyristor current=8.967 A\n",

-        "rms value of thyristor current=12.68 A\n",

-        "pf=0.7797\n"

-       ]

-      }

-     ],

-     "prompt_number": 27

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.33, Page No 363"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=230.0\n",

-      "V_m=math.sqrt(2)*V\n",

-      "a=30.0\n",

-      "L=.0015\n",

-      "\n",

-      "#Calculations\n",

-      "V_o=2*V_m* math.cos(math.radians(a))/math.pi  \n",

-      "R=10\n",

-      "I_o=V_o/R  \n",

-      "f=50\n",

-      "w=2*math.pi*f\n",

-      "V_ox=2*V_m*math.cos(math.radians(a))/math.pi-w*L*I_o/math.pi    \n",

-      "u=math.degrees(math.acos(math.cos(math.radians(a))-I_o*w*L/V_m))-a    \n",

-      "I=I_o\n",

-      "pf=V_o*I_o/(V*I)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"avg o/p voltage=%.3f V\" %V_ox)\n",

-      "print(\"angle of overlap=%.3f deg\" %u)\n",

-      "print(\"pf=%.4f\" %pf)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "avg o/p voltage=176.640 V\n",

-        "angle of overlap=2.855 deg\n",

-        "pf=0.7797\n"

-       ]

-      }

-     ],

-     "prompt_number": 28

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.34, Page No 364"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=415.0\n",

-      "V_ml=math.sqrt(2)*V\n",

-      "a1=35.0 #firing angle advance\n",

-      "\n",

-      "#Calculations\n",

-      "a=180-a1\n",

-      "I_o=80.0\n",

-      "r_s=0.04\n",

-      "v_T=1.5\n",

-      "X_l=.25 #reactance=w*L\n",

-      "E=-3*V_ml*math.cos(math.radians(a))/math.pi+2*I_o*r_s+2*v_T+3*X_l*I_o/math.pi    \n",

-      "\n",

-      "#Results\n",

-      "print(\"mean generator voltage=%.3f V\" %E)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "mean generator voltage=487.590 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 29

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.35, Page No 364"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=415.0\n",

-      "V_ml=math.sqrt(2)*V\n",

-      "R=0.2\n",

-      "I_o=80\n",

-      "r_s=0.04\n",

-      "v_T=1.5\n",

-      "\n",

-      "#Calculations\n",

-      "X_l=.25 #reactance=w*L\n",

-      "a=35\n",

-      "E=-(-3*V_ml*math.cos(math.radians(a))/math.pi+I_o*R+2*I_o*r_s+2*v_T+3*X_l*I_o/math.pi)    \n",

-      "a1=35\n",

-      "a=180-a1\n",

-      "E=(-3*V_ml*math.cos(math.radians(a))/math.pi+I_o*R+2*I_o*r_s+2*v_T+3*X_l*I_o/math.pi) \n",

-      "\n",

-      "#Results\n",

-      "print(\"when firing angle=35deg\")   \n",

-      "print(\"mean generator voltage=%.3f V\" %E)\n",

-      "print(\"when firing angle advance=35deg\")\n",

-      "print(\"mean generator voltage=%.3f V\" %E)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "when firing angle=35deg\n",

-        "mean generator voltage=503.590 V\n",

-        "when firing angle advance=35deg\n",

-        "mean generator voltage=503.590 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 30

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.36, Page No 365"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "R=5.0\n",

-      "V=230.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_mp=math.sqrt(2)*V\n",

-      "a=30.0\n",

-      "E=150.0\n",

-      "B=180-math.degrees(math.asin(E/V_mp))\n",

-      "I_o=(3/(2*math.pi*R))*(V_mp*(math.cos(math.radians(a+30))-math.cos(math.radians(B)))-E*((B-a-30)*math.pi/180))\n",

-      "\n",

-      "#Results\n",

-      "print(\"avg current flowing=%.2f A\" %I_o)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "avg current flowing=19.96 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 31

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.37, Page No 366"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "a=30.0\n",

-      "V=230.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_m=math.sqrt(2)*V\n",

-      "V_o=V_m*(1+math.cos(math.radians(a)))/math.pi    \n",

-      "E=100\n",

-      "R=10\n",

-      "I_o=(V_o-E)/R    \n",

-      "I_TA=I_o*math.pi/(2*math.pi)    \n",

-      "I_Tr=math.sqrt(I_o**2*math.pi/(2*math.pi))    \n",

-      "I_s=math.sqrt(I_o**2*(1-a/180)*math.pi/(math.pi))\n",

-      "I_or=I_o\n",

-      "P=E*I_o+I_or**2*R\n",

-      "pf=(P/(V*I_s))   \n",

-      "f=50\n",

-      "w=2*math.pi*f\n",

-      "t_c=(1-a/180)*math.pi/w    \n",

-      "\n",

-      "#Results\n",

-      "print(\"\\navg o/p current=%.2f A\" %I_o)\n",

-      "print(\"avg o/p voltage=%.3f V\" %V_o)\n",

-      "print(\"avg value of thyristor current=%.2f A\" %I_TA)\n",

-      "print(\"rms value of thyristor current=%.3f A\" %I_Tr)\n",

-      "print(\"avg value of diode current=%.2f A\" %I_TA)\n",

-      "print(\"rms value of diode current=%.3f A\" %I_Tr)\n",

-      "print(\"pf=%.4f\" %pf)\n",

-      "print(\"circuit turn off time=%.2f ms\" %(t_c*1000))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "\n",

-        "avg o/p current=9.32 A\n",

-        "avg o/p voltage=193.202 V\n",

-        "avg value of thyristor current=4.66 A\n",

-        "rms value of thyristor current=6.590 A\n",

-        "avg value of diode current=4.66 A\n",

-        "rms value of diode current=6.590 A\n",

-        "pf=0.9202\n",

-        "circuit turn off time=8.33 ms\n"

-       ]

-      }

-     ],

-     "prompt_number": 32

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.38, Page No 368"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=230.0\n",

-      "V_m=math.sqrt(2)*V\n",

-      "L=0.05\n",

-      "f=50.0\n",

-      "\n",

-      "#Calculations\n",

-      "w=2*math.pi*f\n",

-      "a=30\n",

-      "i_cp=2*V_m*(1-math.cos(math.radians(a)))/(w*L)    \n",

-      "R=30.0\n",

-      "i_l=V_m/R\n",

-      "i1=i_cp+i_l    \n",

-      "i2=i_cp    \n",

-      "\n",

-      "#Results\n",

-      "print(\"peak value of circulating current=%.3f A\" %i_cp)\n",

-      "print(\"peak value of current in convertor 1=%.3f A\" %i1)\n",

-      "print(\"peak value of current in convertor 2=%.3f A\" %i2)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "peak value of circulating current=5.548 A\n",

-        "peak value of current in convertor 1=16.391 A\n",

-        "peak value of current in convertor 2=5.548 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 33

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.39, Page No 370"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "f=50.0\n",

-      "w=2*math.pi*f\n",

-      "R=5.0\n",

-      "L=0.05\n",

-      "\n",

-      "#Calculations\n",

-      "phi=math.degrees(math.atan(w*L/R))  \n",

-      "phi=90+math.degrees(math.atan(w*L/R))   \n",

-      "\n",

-      "#Results\n",

-      "print(\"for no current transients\")\n",

-      "print(\"triggering angle=%.2f deg\" %phi)\n",

-      "print(\"for worst transients\")\n",

-      "print(\"triggering angle=%.2f deg\" %phi)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for no current transients\n",

-        "triggering angle=162.34 deg\n",

-        "for worst transients\n",

-        "triggering angle=162.34 deg\n"

-       ]

-      }

-     ],

-     "prompt_number": 34

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Power_Electronics/Chapter6_1.ipynb b/_Power_Electronics/Chapter6_1.ipynb
deleted file mode 100755
index dff6564b..00000000
--- a/_Power_Electronics/Chapter6_1.ipynb
+++ /dev/null
@@ -1,1761 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 06 : Phase Controlled Rectifiers"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.1, Page No 283"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=230.0\n",

-      "P=1000.0\n",

-      "R=V**2/P\n",

-      "\n",

-      "#Calculations\n",

-      "a=math.pi/4\n",

-      "V_or1=(math.sqrt(2)*V/(2*math.sqrt(math.pi)))*math.sqrt((math.pi-a)+.5*math.sin(2*a))\n",

-      "P1=V_or1**2/R    \n",

-      "a=math.pi/2\n",

-      "V_or2=(math.sqrt(2)*V/(2*math.sqrt(math.pi)))*math.sqrt((math.pi-a)+.5*math.sin(2*a))\n",

-      "P2=V_or2**2/R   \n",

-      "\n",

-      "#Results\n",

-      "print(\"when firing angle delay is of 45deg\")\n",

-      "print(\"power absorbed=%.2f W\" %P1)\n",

-      "print(\"when firing angle delay is of 90deg\")\n",

-      "print(\"power absorbed=%.2f W\" %P2)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "when firing angle delay is of 45deg\n",

-        "power absorbed=454.58 W\n",

-        "when firing angle delay is of 90deg\n",

-        "power absorbed=250.00 W\n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.2, Page No 283"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=230.0\n",

-      "E=150.0\n",

-      "R=8.0\n",

-      "\n",

-      "#Calculations\n",

-      "th1=math.sin(math.radians(E/(math.sqrt(2)*V)))\n",

-      "I_o=(1/(2*math.pi*R))*(2*math.sqrt(2)*230*math.cos(math.radians(th1))-E*(math.pi-2*th1*math.pi/180))    \n",

-      "P=E*I_o    \n",

-      "I_or=math.sqrt((1/(2*math.pi*R**2))*((V**2+E**2)*(math.pi-2*th1*math.pi/180)+V**2*math.sin(math.radians(2*th1))-4*math.sqrt(2)*V*E*math.cos(math.radians(th1))))\n",

-      "P_r=I_or**2*R    \n",

-      "pf=(P+P_r)/(V*I_or)\n",

-      "\n",

-      "#Results\n",

-      "print(\"avg charging curent=%.4f A\" %I_o)\n",

-      "print(\"power supplied to the battery=%.2f W\" %P)\n",

-      "print(\"power dissipated by the resistor=%.3f W\" %P_r)    \n",

-      "print(\"supply pf=%.3f\" %pf)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "avg charging curent=3.5679 A\n",

-        "power supplied to the battery=535.18 W\n",

-        "power dissipated by the resistor=829.760 W\n",

-        "supply pf=0.583\n"

-       ]

-      }

-     ],

-     "prompt_number": 2

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.3 Page No 284"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=230.0\n",

-      "E=150.0\n",

-      "R=8.0\n",

-      "a=35.0\n",

-      "\n",

-      "#Calculations\n",

-      "th1=math.degrees(math.asin(E/(math.sqrt(2)*V)))\n",

-      "th2=180-th1\n",

-      "I_o=(1/(2*math.pi*R))*(math.sqrt(2)*230*(math.cos(math.radians(a))-math.cos(math.radians(th2)))-E*((th2-a)*math.pi/180))    \n",

-      "P=E*I_o    \n",

-      "I_or=math.sqrt((1/(2*math.pi*R**2))*((V**2+E**2)*((th2-a)*math.pi/180)-(V**2/2)*(math.sin(math.radians(2*th2))-math.sin(math.radians(2*a)))-2*math.sqrt(2)*V*E*(math.cos(math.radians(a))-math.cos(math.radians(th2)))))\n",

-      "P_r=I_or**2*R    \n",

-      "pf=(P+P_r)/(V*I_or)    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"avg charging curent=%.4f A\" %I_o)\n",

-      "print(\"power supplied to the battery=%.2f W\" %P)\n",

-      "print(\"power dissipated by the resistor=%.2f W\" %P_r)\n",

-      "print(\"supply pf=%.4f\" %pf)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "avg charging curent=4.9208 A\n",

-        "power supplied to the battery=738.12 W\n",

-        "power dissipated by the resistor=689.54 W\n",

-        "supply pf=0.6686\n"

-       ]

-      }

-     ],

-     "prompt_number": 3

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.4, Page No 285"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "B=210\n",

-      "f=50.0     #Hz\n",

-      "w=2*math.pi*f\n",

-      "a=40.0     #firing angle\n",

-      "V=230.0\n",

-      "R=5.0\n",

-      "L=2*10**-3\n",

-      "\n",

-      "#Calculations\n",

-      "t_c1=(360-B)*math.pi/(180*w)   \n",

-      "V_o1=(math.sqrt(2)*230/(2*math.pi))*(math.cos(math.radians(a))-math.cos(math.radians(B)))    \n",

-      "I_o1=V_o1/R    \n",

-      "E=110\n",

-      "R=5\n",

-      "L=2*10**-3\n",

-      "th1=math.degrees(math.asin(E/(math.sqrt(2)*V)))\n",

-      "t_c2=(360-B+th1)*math.pi/(180*w)    \n",

-      "V_o2=(math.sqrt(2)*230/(2*math.pi))*(math.cos(math.radians(a))-math.cos(math.radians(B)))    \n",

-      "I_o2=(1/(2*math.pi*R))*(math.sqrt(2)*230*(math.cos(math.radians(a))-math.cos(math.radians(B)))-E*((B-a)*math.pi/180))   \n",

-      "V_o2=R*I_o2+E    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"for R=5ohm and L=2mH\")\n",

-      "print(\"ckt turn off time=%.3f msec\" %(t_c1*1000))\n",

-      "print(\"avg output voltage=%.3f V\" %V_o1)\n",

-      "print(\"avg output current=%.4f A\" %I_o1)\n",

-      "print(\"for R=5ohm % L=2mH and E=110V\")\n",

-      "print(\"ckt turn off time=%.3f msec\" %(t_c2*1000))\n",

-      "print(\"avg output current=%.4f A\" %I_o2)\n",

-      "print(\"avg output voltage=%.3f V\" %V_o2)   "

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for R=5ohm and L=2mH\n",

-        "ckt turn off time=8.333 msec\n",

-        "avg output voltage=84.489 V\n",

-        "avg output current=16.8979 A\n",

-        "for R=5ohm % L=2mH and E=110V\n",

-        "ckt turn off time=9.431 msec\n",

-        "avg output current=6.5090 A\n",

-        "avg output voltage=142.545 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 4

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.5 Page No 286"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "f=50.0\n",

-      "R=10.0\n",

-      "a=60.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_m=(math.sqrt(2)*V_s)\n",

-      "V_o=V_m/(2*math.pi)*(1+math.cos(math.radians(a)))\n",

-      "I_o=V_o/R\n",

-      "V_or=(V_m/(2*math.sqrt(math.pi)))*math.sqrt((math.pi-a*math.pi/180)+.5*math.sin(math.radians(2*a)))\n",

-      "I_or=V_or/R\n",

-      "P_dc=V_o*I_o\n",

-      "P_ac=V_or*I_or\n",

-      "RE=P_dc/P_ac    \n",

-      "FF=V_or/V_o    \n",

-      "VRF=math.sqrt(FF**2-1)    \n",

-      "TUF=P_dc/(V_s*I_or)    \n",

-      "PIV=V_m    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"rectification efficiency=%.4f\" %RE)\n",

-      "print(\"form factor=%.3f\" %FF)\n",

-      "print(\"voltage ripple factor=%.4f\" %VRF)\n",

-      "print(\"t/f utilisation factor=%.4f\" %TUF)\n",

-      "print(\"PIV of thyristor=%.2f V\" %PIV)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rectification efficiency=0.2834\n",

-        "form factor=1.879\n",

-        "voltage ripple factor=1.5903\n",

-        "t/f utilisation factor=0.1797\n",

-        "PIV of thyristor=325.27 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 5

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.6 Page No 294"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=1000.0\n",

-      "fos=2.5     #factor of safety\n",

-      "I_TAV=40.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_m1=V/(2*fos)\n",

-      "P1=(2*V_m1/math.pi)*I_TAV    \n",

-      "V_m2=V/(fos)\n",

-      "P2=(2*V_m2/math.pi)*I_TAV    \n",

-      "\n",

-      "#Results\n",

-      "print(\"for mid pt convertor\")\n",

-      "print(\"power handled=%.3f kW\" %(P1/1000))\n",

-      "print(\"for bridge convertor\")\n",

-      "print(\"power handled=%.3f kW\" %(P2/1000))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for mid pt convertor\n",

-        "power handled=5.093 kW\n",

-        "for bridge convertor\n",

-        "power handled=10.186 kW\n"

-       ]

-      }

-     ],

-     "prompt_number": 6

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.7, Page No 297"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "R=.4\n",

-      "I_o=10\n",

-      "I_or=I_o\n",

-      "E=120.0\n",

-      "\n",

-      "#Calculations\n",

-      "a1=math.degrees(math.acos((E+I_o*R)*math.pi/(2*V_m)))\n",

-      "pf1=(E*I_o+I_or**2*R)/(V_s*I_or)    \n",

-      "E=-120.0\n",

-      "a2=math.degrees(math.acos((E+I_o*R)*math.pi/(2*V_m))) \n",

-      "pf2=(-E*I_o-I_or**2*R)/(V_s*I_or)   \n",

-      "\n",

-      "#Results\n",

-      "print(\"firing angle delay=%.2f deg\" %a1)\n",

-      "print(\"pf=%.4f\" %pf1)\n",

-      "print(\"firing angle delay=%.2f deg\" %a2)\n",

-      "print(\"pf=%.4f\" %pf2)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "firing angle delay=53.21 deg\n",

-        "pf=0.5391\n",

-        "firing angle delay=124.07 deg\n",

-        "pf=0.5043\n"

-       ]

-      }

-     ],

-     "prompt_number": 7

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.9 Page No 299"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "f=50.0\n",

-      "a=45.0\n",

-      "R=5.0\n",

-      "E=100.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_o=((math.sqrt(2)*V_s)/(2*math.pi))*(3+math.cos(math.radians(a)))\n",

-      "I_o=(V_o-E)/R    \n",

-      "P=E*I_o    \n",

-      "\n",

-      "#Results\n",

-      "print(\"avg o/p current=%.3f A\" %I_o)\n",

-      "print(\"power delivered to battery=%.4f kW\" %(P/1000))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "avg o/p current=18.382 A\n",

-        "power delivered to battery=1.8382 kW\n"

-       ]

-      }

-     ],

-     "prompt_number": 8

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.10 Page No 300"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variablesV_s=230\n",

-      "f=50.0\n",

-      "a=50.0\n",

-      "R=6.0\n",

-      "E=60.0\n",

-      "V_o1=((math.sqrt(2)*2*V_s)/(math.pi))*math.cos(math.radians(a))\n",

-      "I_o1=(V_o1-E)/R    \n",

-      "\n",

-      "#ATQ after applying the conditions\n",

-      "V_o2=((math.sqrt(2)*V_s)/(math.pi))*math.cos(math.radians(a))\n",

-      "I_o2=(V_o2-E)/R    \n",

-      "\n",

-      "print(\"avg o/p current=%.3f A\" %I_o1)\n",

-      "print(\"avg o/p current after change=%.2f A\" %I_o2)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "avg o/p current=12.184 A\n",

-        "avg o/p current after change=1.09 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 9

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.11 Page No 309"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "a=45.0\n",

-      "R=10.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_o=(2*V_m/math.pi)*math.cos(math.radians(a))\n",

-      "I_o=V_o/R\n",

-      "V_or=V_m/math.sqrt(2)\n",

-      "I_or=I_o\n",

-      "P_dc=V_o*I_o\n",

-      "P_ac=V_or*I_or\n",

-      "RE=P_dc/P_ac    \n",

-      "FF=V_or/V_o    \n",

-      "VRF=math.sqrt(FF**2-1)    \n",

-      "I_s1=2*math.sqrt(2)*I_o/math.pi\n",

-      "DF=math.cos(math.radians(a))\n",

-      "CDF=.90032\n",

-      "pf=CDF*DF    \n",

-      "HF=math.sqrt((1/CDF**2)-1)    \n",

-      "Q=2*V_m*I_o*math.sin(math.radians(a))/math.pi \n",

-      "\n",

-      "#Results\n",

-      "print(\"rectification efficiency=%.4f\" %RE)\n",

-      "print(\"form factor=%.4f\" %FF)\n",

-      "print(\"voltage ripple factor=%.4f\" %VRF)\n",

-      "print(\"pf=%.5f\" %pf)\n",

-      "print(\"HF=%.5f\" %HF)\n",

-      "print(\"active power=%.2f W\" %P_dc)   \n",

-      "print(\"reactive power=%.3f Var\" %Q)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rectification efficiency=0.6366\n",

-        "form factor=1.5708\n",

-        "voltage ripple factor=1.2114\n",

-        "pf=0.63662\n",

-        "HF=0.48342\n",

-        "active power=2143.96 W\n",

-        "reactive power=2143.956 Var\n"

-       ]

-      }

-     ],

-     "prompt_number": 10

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.12, Page No 310"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "a=45.0\n",

-      "R=10.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_o=(V_m/math.pi)*(1+math.cos(math.radians(a)))\n",

-      "I_o=V_o/R\n",

-      "V_or=V_s*math.sqrt((1/math.pi)*((math.pi-a*math.pi/180)+math.sin(math.radians(2*a))/2))\n",

-      "I_or=I_o\n",

-      "P_dc=V_o*I_o\n",

-      "P_ac=V_or*I_or\n",

-      "RE=P_dc/P_ac    \n",

-      "FF=V_or/V_o    \n",

-      "VRF=math.sqrt(FF**2-1)    \n",

-      "I_s1=2*math.sqrt(2)*I_o*math.cos(math.radians(a/2))/math.pi\n",

-      "DF=math.cos(math.radians(a/2))   \n",

-      "CDF=2*math.sqrt(2)*math.cos(math.radians(a/2))/math.sqrt(math.pi*(math.pi-a*math.pi/180))    \n",

-      "pf=CDF*DF    \n",

-      "HF=math.sqrt((1/CDF**2)-1)    \n",

-      "Q=V_m*I_o*math.sin(math.radians(a))/math.pi\n",

-      "\n",

-      "#Results\n",

-      "print(\"form factor=%.3f\" %FF)\n",

-      "print(\"rectification efficiency=%.4f\" %RE)\n",

-      "print(\"voltage ripple factor=%.3f\" %VRF)    \n",

-      "print(\"DF=%.4f\" %DF)\n",

-      "print(\"CDF=%.4f\" %CDF)\n",

-      "print(\"pf=%.4f\" %pf)\n",

-      "print(\"HF=%.4f\" %HF)\n",

-      "print(\"active power=%.3f W\" %P_dc)\n",

-      "print(\"reactive power=%.2f Var\" %Q)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "form factor=1.241\n",

-        "rectification efficiency=0.8059\n",

-        "voltage ripple factor=0.735\n",

-        "DF=0.9239\n",

-        "CDF=0.9605\n",

-        "pf=0.8874\n",

-        "HF=0.2899\n",

-        "active power=3123.973 W\n",

-        "reactive power=1293.99 Var\n"

-       ]

-      }

-     ],

-     "prompt_number": 11

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.13, Page No 319"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "R=10.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_ml=math.sqrt(2)*V_s\n",

-      "V_om=3*V_ml/(2*math.pi)\n",

-      "V_o=V_om/2\n",

-      "th=30\n",

-      "a=math.degrees(math.acos((2*math.pi*math.sqrt(3)*V_o/(3*V_ml)-1)))-th    \n",

-      "I_o=V_o/R    \n",

-      "V_or=V_ml/(2*math.sqrt(math.pi))*math.sqrt((5*math.pi/6-a*math.pi/180)+.5*math.sin(math.radians(2*a+2*th)))\n",

-      "I_or=V_or/R    \n",

-      "RE=V_o*I_o/(V_or*I_or)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"delay angle=%.1f deg\" %a)\n",

-      "print(\"avg load current=%.3f A\" %I_o)\n",

-      "print(\"rms load current=%.3f A\" %I_or)\n",

-      "print(\"rectification efficiency=%.4f\" %RE)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "delay angle=67.7 deg\n",

-        "avg load current=7.765 A\n",

-        "rms load current=10.477 A\n",

-        "rectification efficiency=0.5494\n"

-       ]

-      }

-     ],

-     "prompt_number": 12

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.15, Page No 321"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=400.0\n",

-      "V_ml=math.sqrt(2)*V\n",

-      "v_T=1.4\n",

-      "a1=30.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_o1=3*V_ml/(2*math.pi)*math.cos(math.radians(a1))-v_T   \n",

-      "a2=60.0\n",

-      "V_o2=3*V_ml/(2*math.pi)*math.cos(math.radians(a2))-v_T  \n",

-      "I_o=36\n",

-      "I_TA=I_o/3    \n",

-      "I_Tr=I_o/math.sqrt(3)    \n",

-      "P=I_TA*v_T       \n",

-      "\n",

-      "#Results\n",

-      "print(\"for firing angle = 30deg\")\n",

-      "print(\"avg output voltage=%.3f V\" %V_o1)\n",

-      "print(\"for firing angle = 60deg\")\n",

-      "print(\"avg output voltage=%.2f V\" %V_o2)\n",

-      "print(\"avg current rating=%.0f A\" %I_TA)\n",

-      "print(\"rms current rating=%.3f A\" %I_Tr)\n",

-      "print(\"PIV of SCR=%.1f V\" %V_ml)\n",

-      "print(\"power dissipated=%.1f W\" %P)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for firing angle = 30deg\n",

-        "avg output voltage=232.509 V\n",

-        "for firing angle = 60deg\n",

-        "avg output voltage=133.65 V\n",

-        "avg current rating=12 A\n",

-        "rms current rating=20.785 A\n",

-        "PIV of SCR=565.7 V\n",

-        "power dissipated=16.8 W\n"

-       ]

-      }

-     ],

-     "prompt_number": 13

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.17, Page No 331"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "E=200\n",

-      "I_o=20\n",

-      "R=.5\n",

-      "\n",

-      "#Calculations\n",

-      "V_o1=E+I_o*R\n",

-      "V_s=230\n",

-      "V_ml=math.sqrt(2)*V_s\n",

-      "a1=math.degrees(math.acos(V_o1*math.pi/(3*V_ml)))\n",

-      "th=120\n",

-      "I_s=math.sqrt((1/math.pi)*I_o**2*th*math.pi/180)\n",

-      "P=E*I_o+I_o**2*R\n",

-      "pf=P/(math.sqrt(3)*V_s*I_s)    \n",

-      "V_o2=E-I_o*R\n",

-      "a2=math.degrees(math.acos(-V_o2*math.pi/(3*V_ml))) \n",

-      "\n",

-      "#Results\n",

-      "print(\"firing angle delay=%.3f deg\" %a1)\n",

-      "print(\"pf=%.3f\" %pf)\n",

-      "print(\"firing angle delay=%.2f deg\" %a2)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "firing angle delay=47.461 deg\n",

-        "pf=0.646\n",

-        "firing angle delay=127.71 deg\n"

-       ]

-      }

-     ],

-     "prompt_number": 14

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.18, Page No 332"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=230.0\n",

-      "f=50.0\n",

-      "\n",

-      "#Calculations\n",

-      "w=2*math.pi*f\n",

-      "a1=0\n",

-      "t_c1=(4*math.pi/3-a1*math.pi/180)/w    \n",

-      "a2=30\n",

-      "t_c2=(4*math.pi/3-a2*math.pi/180)/w    \n",

-      "\n",

-      "#Results\n",

-      "print(\"for firing angle delay=0deg\")\n",

-      "print(\"commutation time=%.2f ms\" %(t_c1*1000))\n",

-      "print(\"peak reverse voltage=%.2f V\" %(math.sqrt(2)*V))\n",

-      "print(\"for firing angle delay=30deg\")\n",

-      "print(\"commutation time=%.2f ms\" %(t_c2*1000))\n",

-      "print(\"peak reverse voltage=%.2f V\" %(math.sqrt(2)*V))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for firing angle delay=0deg\n",

-        "commutation time=13.33 ms\n",

-        "peak reverse voltage=325.27 V\n",

-        "for firing angle delay=30deg\n",

-        "commutation time=11.67 ms\n",

-        "peak reverse voltage=325.27 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 15

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.19, Page No 333"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "a=30.0\n",

-      "R=10.0\n",

-      "P=5000.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_s=math.sqrt(P*R*2*math.pi/(2*3)/(math.pi/3+math.sqrt(3)*math.cos(math.radians(2*a))/2))\n",

-      "V_ph=V_s/math.sqrt(3)    \n",

-      "I_or=math.sqrt(P*R)\n",

-      "V_s=I_or*math.pi/(math.sqrt(2)*3*math.cos(math.radians(a)))\n",

-      "V_ph=V_s/math.sqrt(3) \n",

-      "\n",

-      "#Results\n",

-      "print(\"per phase voltage percent V_ph=%.3f V\" %V_ph)   \n",

-      "print(\"for constant load current\")\n",

-      "print(\"V_ph=%.2f V\" %V_ph)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "per phase voltage percent V_ph=110.384 V\n",

-        "for constant load current\n",

-        "V_ph=110.38 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 16

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.20, Page No 334"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "a=30.0\n",

-      "R=10.0\n",

-      "P=5000.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_s=math.sqrt(P*R*4*math.pi/(2*3)/(2*math.pi/3+math.sqrt(3)*(1+math.cos(math.radians(2*a)))/2))\n",

-      "V_ph=V_s/math.sqrt(3)    \n",

-      "I_or=math.sqrt(P*R)\n",

-      "V_s=I_or*2*math.pi/(math.sqrt(2)*3*(1+math.cos(math.radians(a))))\n",

-      "V_ph=V_s/math.sqrt(3)   \n",

-      "\n",

-      "#Results\n",

-      "print(\"per phase voltage percent V_ph=%.3f V\" %V_ph) \n",

-      "print(\"for constant load current\")\n",

-      "print(\"V_ph=%.2f V\" %V_ph)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "per phase voltage percent V_ph=102.459 V\n",

-        "for constant load current\n",

-        "V_ph=102.46 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 17

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.21, Page No 334"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "a=90.0\n",

-      "R=10.0\n",

-      "P=5000.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_s=math.sqrt(P*R*4*math.pi/(2*3)/((math.pi-math.pi/2)+(math.sin(math.radians(2*a)))/2))\n",

-      "V_ph=V_s/math.sqrt(3)    \n",

-      "I_or=math.sqrt(P*R)\n",

-      "V_s=I_or*2*math.pi/(math.sqrt(2)*3*(1+math.cos(math.radians(a))))\n",

-      "V_ph=V_s/math.sqrt(3)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"per phase voltage percent V_ph=%.2f V\" %V_ph)\n",

-      "print(\"for constant load current\")\n",

-      "print(\"V_ph=%.1f V\" %V_ph)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "per phase voltage percent V_ph=191.19 V\n",

-        "for constant load current\n",

-        "V_ph=191.2 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 18

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.22 Page No 334"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "E=200.0\n",

-      "I_o=20.0\n",

-      "R=.5\n",

-      "\n",

-      "#Calculations\n",

-      "V_o=E+I_o*R\n",

-      "V_s=230\n",

-      "V_ml=math.sqrt(2)*V_s\n",

-      "a=math.degrees(math.acos(V_o*2*math.pi/(3*V_ml)-1))  \n",

-      "a1=180-a\n",

-      "I_sr=math.sqrt((1/math.pi)*I_o**2*(a1*math.pi/180))\n",

-      "P=V_o*I_o\n",

-      "pf=P/(math.sqrt(3)*V_s*I_sr)   \n",

-      "\n",

-      "#Results\n",

-      "print(\"firing angle delay=%.2f deg\" %a)\n",

-      "print(\"pf=%.2f\" %pf)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "firing angle delay=69.38 deg\n",

-        "pf=0.67\n"

-       ]

-      }

-     ],

-     "prompt_number": 19

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.23, Page No 335"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=400.0\n",

-      "f=50.0\n",

-      "I_o=15.0\n",

-      "a=45.0\n",

-      "\n",

-      "#Calculations\n",

-      "I_TA=I_o*120.0/360.0\n",

-      "I_Tr=math.sqrt(I_o**2*120/360)\n",

-      "I_sr=math.sqrt(I_o**2*120/180)\n",

-      "V_ml=math.sqrt(2)*V_s\n",

-      "V_o=3*V_ml*math.cos(math.radians(a))/math.pi\n",

-      "V_or=V_ml*math.sqrt((3/(2*math.pi))*(math.pi/3+math.sqrt(3/2)*math.cos(math.radians(2*a))))\n",

-      "I_or=I_o\n",

-      "P_dc=V_o*I_o\n",

-      "P_ac=V_or*I_or\n",

-      "RE=P_dc/P_ac    \n",

-      "VA=3*V_s/math.sqrt(3)*I_sr\n",

-      "TUF=P_dc/VA    \n",

-      "pf=P_ac/VA    \n",

-      "\n",

-      "#Results\n",

-      "print(\"rectification efficiency=%.5f\" %RE)\n",

-      "print(\"TUF=%.4f\" %TUF)\n",

-      "print(\"Input pf=%.3f\" %pf)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rectification efficiency=0.95493\n",

-        "TUF=0.6752\n",

-        "Input pf=0.707\n"

-       ]

-      }

-     ],

-     "prompt_number": 20

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.24, Page No 341"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "I=10.0\n",

-      "a=45.0\n",

-      "V=400.0\n",

-      "f=50.0\n",

-      "\n",

-      "#Calculations\n",

-      "DF=math.cos(math.radians(a))\n",

-      "I_o=10\n",

-      "I_s1=4*I_o/(math.sqrt(2)*math.pi)*math.sin(math.pi/3)\n",

-      "I_sr=I_o*math.sqrt(2.0/3.0)\n",

-      "I_o=1     #suppose\n",

-      "CDF=I_s1/I_sr    \n",

-      "THD=math.sqrt(1/CDF**2-1)    \n",

-      "pf=CDF*DF    \n",

-      "P=(3*math.sqrt(2)*V*math.cos(math.radians(a))/math.pi)*I\n",

-      "Q=(3*math.sqrt(2)*V*math.sin(math.radians(a))/math.pi)*I  \n",

-      "   \n",

-      "#Results\n",

-      "print(\"DF=%.3f\" %DF)\n",

-      "print(\"CDF=%.3f\" %CDF)\n",

-      "print(\"THD=%.5f\" %THD)\n",

-      "print(\"PF=%.4f\" %pf)\n",

-      "print(\"active power=%.2f W\" %P)  \n",

-      "print(\"reactive power=%.2f Var\" %Q)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "DF=0.707\n",

-        "CDF=0.955\n",

-        "THD=0.31084\n",

-        "PF=0.6752\n",

-        "active power=3819.72 W\n",

-        "reactive power=3819.72 Var\n"

-       ]

-      }

-     ],

-     "prompt_number": 21

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.25, Page No 342"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "print(\"for firing angle=30deg\")\n",

-      "a=30.0\n",

-      "V=400.0\n",

-      "V_ml=math.sqrt(2)*V\n",

-      "V_o=3*V_ml*math.cos(math.radians(a))/math.pi\n",

-      "E=350\n",

-      "R=10\n",

-      "\n",

-      "#Calculations\n",

-      "I_o=(V_o-E)/R\n",

-      "I_or=I_o\n",

-      "P1=V_o*I_o    \n",

-      "I_sr=I_o*math.sqrt(2.0/3.0)\n",

-      "VA=3*V/math.sqrt(3)*I_sr\n",

-      "pf=P1/VA \n",

-      "a=180-60\n",

-      "V=400\n",

-      "V_ml=math.sqrt(2)*V\n",

-      "V_o=3*V_ml*math.cos(math.radians(a))/math.pi\n",

-      "E=-350\n",

-      "R=10\n",

-      "I_o=(V_o-E)/R\n",

-      "I_or=I_o\n",

-      "P2=-V_o*I_o    \n",

-      "I_sr=I_o*math.sqrt(2.0/3.0)\n",

-      "VA=3*V/math.sqrt(3)*I_sr\n",

-      "pf=P2/VA       \n",

-      "\n",

-      "print(\"power delivered to load=%.2f W\" %P1)\n",

-      "print(\"pf=%.4f\" %pf)\n",

-      "print(\"for firing advance angle=60deg\")\n",

-      "print(\"power delivered to load=%.2f W\" %P2)\n",

-      "print(\"pf=%.4f\" %pf)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits.\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for firing angle=30deg\n",

-        "power delivered to load=5511.74 W\n",

-        "pf=0.4775\n",

-        "for firing advance angle=60deg\n",

-        "power delivered to load=2158.20 W\n",

-        "pf=0.4775\n"

-       ]

-      }

-     ],

-     "prompt_number": 22

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.26, Page No 347"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "a=0\n",

-      "u=15.0\n",

-      "\n",

-      "#Calculations\n",

-      "i=math.cos(math.radians(a))-math.cos(math.radians(a+u))\n",

-      "a=30\n",

-      "u=math.degrees(math.acos(math.cos(math.radians(a))-i))-a  \n",

-      "a=45\n",

-      "u=math.degrees(math.acos(math.cos(math.radians(a))-i))-a    \n",

-      "a=60\n",

-      "u=math.degrees(math.acos(math.cos(math.radians(a))-i))-a  \n",

-      "\n",

-      "#Results\n",

-      "print(\"for firing angle=30deg\") \n",

-      "print(\"overlap angle=%.1f deg\" %u)\n",

-      "print(\"for firing angle=45deg\")  \n",

-      "print(\"overlap angle=%.1f deg\" %u)\n",

-      "print(\"for firing angle=60deg\") \n",

-      "print(\"overlap angle=%.2f deg\" %u)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for firing angle=30deg\n",

-        "overlap angle=2.2 deg\n",

-        "for firing angle=45deg\n",

-        "overlap angle=2.2 deg\n",

-        "for firing angle=60deg\n",

-        "overlap angle=2.23 deg\n"

-       ]

-      }

-     ],

-     "prompt_number": 23

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.28, Page No 352"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "E=400.0\n",

-      "I_o=20.0\n",

-      "R=1\n",

-      "\n",

-      "#Calculations\n",

-      "V_o=E+I_o*R\n",

-      "f=50.0\n",

-      "w=2*math.pi*f\n",

-      "L=.004\n",

-      "V=230 #per phase voltage\n",

-      "V_ml=math.sqrt(6)*V\n",

-      "a=math.degrees(math.acos(math.pi/(3*V_ml)*(V_o+3*w*L*I_o/math.pi)))   \n",

-      "print(\"firing angle delay=%.3f deg\" %a)\n",

-      "u=math.degrees(math.acos(math.pi/(3*V_ml)*(V_o-3*w*L*I_o/math.pi)))-a    \n",

-      "\n",

-      "#Results\n",

-      "print(\"overlap angle=%.2f deg\" %u)\n",

-      "#Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "firing angle delay=34.382 deg\n",

-        "overlap angle=8.22 deg\n"

-       ]

-      }

-     ],

-     "prompt_number": 24

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.29, Page No 352"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=400.0\n",

-      "f=50.0\n",

-      "w=2*math.pi*f\n",

-      "R=1\n",

-      "E=230\n",

-      "I=15.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_o=-E+I*R\n",

-      "V_ml=math.sqrt(2)*V\n",

-      "a=math.degrees(math.acos(V_o*2*math.pi/(3*V_ml)))  \n",

-      "L=0.004\n",

-      "a=math.degrees(math.acos((2*math.pi)/(3*V_ml)*(V_o+3*w*L*I/(2*math.pi))))  \n",

-      "u=math.degrees(math.acos(math.cos(math.radians(a))-3*f*L*I/V_ml))-a    \n",

-      "\n",

-      "#Results\n",

-      "print(\"firing angle=%.3f deg\" %a)\n",

-      "print(\"firing angle delay=%.3f deg\" %a)\n",

-      "print(\"overlap angle=%.3f deg\" %u)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits.\n",

-      " \n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "firing angle=139.702 deg\n",

-        "firing angle delay=139.702 deg\n",

-        "overlap angle=1.431 deg\n"

-       ]

-      }

-     ],

-     "prompt_number": 25

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.31, Page No 361"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=230.0 #per phase\n",

-      "f=50.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_ml=math.sqrt(3.0)*math.sqrt(2)*V\n",

-      "w=2*math.pi*f\n",

-      "a1=60.0\n",

-      "L=0.015\n",

-      "i_cp=(math.sqrt(3)*V_ml/(w*L))*(1-math.sin(math.radians(a1)))    \n",

-      "\n",

-      "#Results\n",

-      "print(\"circulating current=%.4f A\" %i_cp)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "circulating current=27.7425 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 26

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.32, Page No 362"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=230.0\n",

-      "V_m=math.sqrt(2)*V\n",

-      "a=30.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_o=2*V_m* math.cos(math.radians(a))/math.pi    \n",

-      "R=10\n",

-      "I_o=V_o/R    \n",

-      "I_TA=I_o*math.pi/(2*math.pi)    \n",

-      "I_Tr=math.sqrt(I_o**2*math.pi/(2*math.pi))    \n",

-      "I_s=math.sqrt(I_o**2*math.pi/(math.pi)) \n",

-      "I_o=I_s\n",

-      "pf=(V_o*I_o/(V*I_s))    \n",

-      "\n",

-      "#Results\n",

-      "print(\"avg o/p voltage=%.3f V\" %V_o)\n",

-      "print(\"avg o/p current=%.2f A\" %I_o)\n",

-      "print(\"avg value of thyristor current=%.3f A\" %I_TA)\n",

-      "print(\"rms value of thyristor current=%.2f A\" %I_Tr)\n",

-      "print(\"pf=%.4f\" %pf)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits.\n",

-      " \n",

-      " \n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "avg o/p voltage=179.330 V\n",

-        "avg o/p current=17.93 A\n",

-        "avg value of thyristor current=8.967 A\n",

-        "rms value of thyristor current=12.68 A\n",

-        "pf=0.7797\n"

-       ]

-      }

-     ],

-     "prompt_number": 27

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.33, Page No 363"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=230.0\n",

-      "V_m=math.sqrt(2)*V\n",

-      "a=30.0\n",

-      "L=.0015\n",

-      "\n",

-      "#Calculations\n",

-      "V_o=2*V_m* math.cos(math.radians(a))/math.pi  \n",

-      "R=10\n",

-      "I_o=V_o/R  \n",

-      "f=50\n",

-      "w=2*math.pi*f\n",

-      "V_ox=2*V_m*math.cos(math.radians(a))/math.pi-w*L*I_o/math.pi    \n",

-      "u=math.degrees(math.acos(math.cos(math.radians(a))-I_o*w*L/V_m))-a    \n",

-      "I=I_o\n",

-      "pf=V_o*I_o/(V*I)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"avg o/p voltage=%.3f V\" %V_ox)\n",

-      "print(\"angle of overlap=%.3f deg\" %u)\n",

-      "print(\"pf=%.4f\" %pf)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "avg o/p voltage=176.640 V\n",

-        "angle of overlap=2.855 deg\n",

-        "pf=0.7797\n"

-       ]

-      }

-     ],

-     "prompt_number": 28

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.34, Page No 364"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=415.0\n",

-      "V_ml=math.sqrt(2)*V\n",

-      "a1=35.0 #firing angle advance\n",

-      "\n",

-      "#Calculations\n",

-      "a=180-a1\n",

-      "I_o=80.0\n",

-      "r_s=0.04\n",

-      "v_T=1.5\n",

-      "X_l=.25 #reactance=w*L\n",

-      "E=-3*V_ml*math.cos(math.radians(a))/math.pi+2*I_o*r_s+2*v_T+3*X_l*I_o/math.pi    \n",

-      "\n",

-      "#Results\n",

-      "print(\"mean generator voltage=%.3f V\" %E)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "mean generator voltage=487.590 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 29

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.35, Page No 364"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=415.0\n",

-      "V_ml=math.sqrt(2)*V\n",

-      "R=0.2\n",

-      "I_o=80\n",

-      "r_s=0.04\n",

-      "v_T=1.5\n",

-      "\n",

-      "#Calculations\n",

-      "X_l=.25 #reactance=w*L\n",

-      "a=35\n",

-      "E=-(-3*V_ml*math.cos(math.radians(a))/math.pi+I_o*R+2*I_o*r_s+2*v_T+3*X_l*I_o/math.pi)    \n",

-      "a1=35\n",

-      "a=180-a1\n",

-      "E=(-3*V_ml*math.cos(math.radians(a))/math.pi+I_o*R+2*I_o*r_s+2*v_T+3*X_l*I_o/math.pi) \n",

-      "\n",

-      "#Results\n",

-      "print(\"when firing angle=35deg\")   \n",

-      "print(\"mean generator voltage=%.3f V\" %E)\n",

-      "print(\"when firing angle advance=35deg\")\n",

-      "print(\"mean generator voltage=%.3f V\" %E)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "when firing angle=35deg\n",

-        "mean generator voltage=503.590 V\n",

-        "when firing angle advance=35deg\n",

-        "mean generator voltage=503.590 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 30

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.36, Page No 365"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "R=5.0\n",

-      "V=230.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_mp=math.sqrt(2)*V\n",

-      "a=30.0\n",

-      "E=150.0\n",

-      "B=180-math.degrees(math.asin(E/V_mp))\n",

-      "I_o=(3/(2*math.pi*R))*(V_mp*(math.cos(math.radians(a+30))-math.cos(math.radians(B)))-E*((B-a-30)*math.pi/180))\n",

-      "\n",

-      "#Results\n",

-      "print(\"avg current flowing=%.2f A\" %I_o)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "avg current flowing=19.96 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 31

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.37, Page No 366"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "a=30.0\n",

-      "V=230.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_m=math.sqrt(2)*V\n",

-      "V_o=V_m*(1+math.cos(math.radians(a)))/math.pi    \n",

-      "E=100\n",

-      "R=10\n",

-      "I_o=(V_o-E)/R    \n",

-      "I_TA=I_o*math.pi/(2*math.pi)    \n",

-      "I_Tr=math.sqrt(I_o**2*math.pi/(2*math.pi))    \n",

-      "I_s=math.sqrt(I_o**2*(1-a/180)*math.pi/(math.pi))\n",

-      "I_or=I_o\n",

-      "P=E*I_o+I_or**2*R\n",

-      "pf=(P/(V*I_s))   \n",

-      "f=50\n",

-      "w=2*math.pi*f\n",

-      "t_c=(1-a/180)*math.pi/w    \n",

-      "\n",

-      "#Results\n",

-      "print(\"\\navg o/p current=%.2f A\" %I_o)\n",

-      "print(\"avg o/p voltage=%.3f V\" %V_o)\n",

-      "print(\"avg value of thyristor current=%.2f A\" %I_TA)\n",

-      "print(\"rms value of thyristor current=%.3f A\" %I_Tr)\n",

-      "print(\"avg value of diode current=%.2f A\" %I_TA)\n",

-      "print(\"rms value of diode current=%.3f A\" %I_Tr)\n",

-      "print(\"pf=%.4f\" %pf)\n",

-      "print(\"circuit turn off time=%.2f ms\" %(t_c*1000))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "\n",

-        "avg o/p current=9.32 A\n",

-        "avg o/p voltage=193.202 V\n",

-        "avg value of thyristor current=4.66 A\n",

-        "rms value of thyristor current=6.590 A\n",

-        "avg value of diode current=4.66 A\n",

-        "rms value of diode current=6.590 A\n",

-        "pf=0.9202\n",

-        "circuit turn off time=8.33 ms\n"

-       ]

-      }

-     ],

-     "prompt_number": 32

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.38, Page No 368"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=230.0\n",

-      "V_m=math.sqrt(2)*V\n",

-      "L=0.05\n",

-      "f=50.0\n",

-      "\n",

-      "#Calculations\n",

-      "w=2*math.pi*f\n",

-      "a=30\n",

-      "i_cp=2*V_m*(1-math.cos(math.radians(a)))/(w*L)    \n",

-      "R=30.0\n",

-      "i_l=V_m/R\n",

-      "i1=i_cp+i_l    \n",

-      "i2=i_cp    \n",

-      "\n",

-      "#Results\n",

-      "print(\"peak value of circulating current=%.3f A\" %i_cp)\n",

-      "print(\"peak value of current in convertor 1=%.3f A\" %i1)\n",

-      "print(\"peak value of current in convertor 2=%.3f A\" %i2)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "peak value of circulating current=5.548 A\n",

-        "peak value of current in convertor 1=16.391 A\n",

-        "peak value of current in convertor 2=5.548 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 33

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.39, Page No 370"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "f=50.0\n",

-      "w=2*math.pi*f\n",

-      "R=5.0\n",

-      "L=0.05\n",

-      "\n",

-      "#Calculations\n",

-      "phi=math.degrees(math.atan(w*L/R))  \n",

-      "phi=90+math.degrees(math.atan(w*L/R))   \n",

-      "\n",

-      "#Results\n",

-      "print(\"for no current transients\")\n",

-      "print(\"triggering angle=%.2f deg\" %phi)\n",

-      "print(\"for worst transients\")\n",

-      "print(\"triggering angle=%.2f deg\" %phi)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for no current transients\n",

-        "triggering angle=162.34 deg\n",

-        "for worst transients\n",

-        "triggering angle=162.34 deg\n"

-       ]

-      }

-     ],

-     "prompt_number": 34

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Power_Electronics/Chapter6_2.ipynb b/_Power_Electronics/Chapter6_2.ipynb
deleted file mode 100755
index dff6564b..00000000
--- a/_Power_Electronics/Chapter6_2.ipynb
+++ /dev/null
@@ -1,1761 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 06 : Phase Controlled Rectifiers"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.1, Page No 283"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=230.0\n",

-      "P=1000.0\n",

-      "R=V**2/P\n",

-      "\n",

-      "#Calculations\n",

-      "a=math.pi/4\n",

-      "V_or1=(math.sqrt(2)*V/(2*math.sqrt(math.pi)))*math.sqrt((math.pi-a)+.5*math.sin(2*a))\n",

-      "P1=V_or1**2/R    \n",

-      "a=math.pi/2\n",

-      "V_or2=(math.sqrt(2)*V/(2*math.sqrt(math.pi)))*math.sqrt((math.pi-a)+.5*math.sin(2*a))\n",

-      "P2=V_or2**2/R   \n",

-      "\n",

-      "#Results\n",

-      "print(\"when firing angle delay is of 45deg\")\n",

-      "print(\"power absorbed=%.2f W\" %P1)\n",

-      "print(\"when firing angle delay is of 90deg\")\n",

-      "print(\"power absorbed=%.2f W\" %P2)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "when firing angle delay is of 45deg\n",

-        "power absorbed=454.58 W\n",

-        "when firing angle delay is of 90deg\n",

-        "power absorbed=250.00 W\n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.2, Page No 283"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=230.0\n",

-      "E=150.0\n",

-      "R=8.0\n",

-      "\n",

-      "#Calculations\n",

-      "th1=math.sin(math.radians(E/(math.sqrt(2)*V)))\n",

-      "I_o=(1/(2*math.pi*R))*(2*math.sqrt(2)*230*math.cos(math.radians(th1))-E*(math.pi-2*th1*math.pi/180))    \n",

-      "P=E*I_o    \n",

-      "I_or=math.sqrt((1/(2*math.pi*R**2))*((V**2+E**2)*(math.pi-2*th1*math.pi/180)+V**2*math.sin(math.radians(2*th1))-4*math.sqrt(2)*V*E*math.cos(math.radians(th1))))\n",

-      "P_r=I_or**2*R    \n",

-      "pf=(P+P_r)/(V*I_or)\n",

-      "\n",

-      "#Results\n",

-      "print(\"avg charging curent=%.4f A\" %I_o)\n",

-      "print(\"power supplied to the battery=%.2f W\" %P)\n",

-      "print(\"power dissipated by the resistor=%.3f W\" %P_r)    \n",

-      "print(\"supply pf=%.3f\" %pf)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "avg charging curent=3.5679 A\n",

-        "power supplied to the battery=535.18 W\n",

-        "power dissipated by the resistor=829.760 W\n",

-        "supply pf=0.583\n"

-       ]

-      }

-     ],

-     "prompt_number": 2

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.3 Page No 284"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=230.0\n",

-      "E=150.0\n",

-      "R=8.0\n",

-      "a=35.0\n",

-      "\n",

-      "#Calculations\n",

-      "th1=math.degrees(math.asin(E/(math.sqrt(2)*V)))\n",

-      "th2=180-th1\n",

-      "I_o=(1/(2*math.pi*R))*(math.sqrt(2)*230*(math.cos(math.radians(a))-math.cos(math.radians(th2)))-E*((th2-a)*math.pi/180))    \n",

-      "P=E*I_o    \n",

-      "I_or=math.sqrt((1/(2*math.pi*R**2))*((V**2+E**2)*((th2-a)*math.pi/180)-(V**2/2)*(math.sin(math.radians(2*th2))-math.sin(math.radians(2*a)))-2*math.sqrt(2)*V*E*(math.cos(math.radians(a))-math.cos(math.radians(th2)))))\n",

-      "P_r=I_or**2*R    \n",

-      "pf=(P+P_r)/(V*I_or)    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"avg charging curent=%.4f A\" %I_o)\n",

-      "print(\"power supplied to the battery=%.2f W\" %P)\n",

-      "print(\"power dissipated by the resistor=%.2f W\" %P_r)\n",

-      "print(\"supply pf=%.4f\" %pf)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "avg charging curent=4.9208 A\n",

-        "power supplied to the battery=738.12 W\n",

-        "power dissipated by the resistor=689.54 W\n",

-        "supply pf=0.6686\n"

-       ]

-      }

-     ],

-     "prompt_number": 3

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.4, Page No 285"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "B=210\n",

-      "f=50.0     #Hz\n",

-      "w=2*math.pi*f\n",

-      "a=40.0     #firing angle\n",

-      "V=230.0\n",

-      "R=5.0\n",

-      "L=2*10**-3\n",

-      "\n",

-      "#Calculations\n",

-      "t_c1=(360-B)*math.pi/(180*w)   \n",

-      "V_o1=(math.sqrt(2)*230/(2*math.pi))*(math.cos(math.radians(a))-math.cos(math.radians(B)))    \n",

-      "I_o1=V_o1/R    \n",

-      "E=110\n",

-      "R=5\n",

-      "L=2*10**-3\n",

-      "th1=math.degrees(math.asin(E/(math.sqrt(2)*V)))\n",

-      "t_c2=(360-B+th1)*math.pi/(180*w)    \n",

-      "V_o2=(math.sqrt(2)*230/(2*math.pi))*(math.cos(math.radians(a))-math.cos(math.radians(B)))    \n",

-      "I_o2=(1/(2*math.pi*R))*(math.sqrt(2)*230*(math.cos(math.radians(a))-math.cos(math.radians(B)))-E*((B-a)*math.pi/180))   \n",

-      "V_o2=R*I_o2+E    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"for R=5ohm and L=2mH\")\n",

-      "print(\"ckt turn off time=%.3f msec\" %(t_c1*1000))\n",

-      "print(\"avg output voltage=%.3f V\" %V_o1)\n",

-      "print(\"avg output current=%.4f A\" %I_o1)\n",

-      "print(\"for R=5ohm % L=2mH and E=110V\")\n",

-      "print(\"ckt turn off time=%.3f msec\" %(t_c2*1000))\n",

-      "print(\"avg output current=%.4f A\" %I_o2)\n",

-      "print(\"avg output voltage=%.3f V\" %V_o2)   "

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for R=5ohm and L=2mH\n",

-        "ckt turn off time=8.333 msec\n",

-        "avg output voltage=84.489 V\n",

-        "avg output current=16.8979 A\n",

-        "for R=5ohm % L=2mH and E=110V\n",

-        "ckt turn off time=9.431 msec\n",

-        "avg output current=6.5090 A\n",

-        "avg output voltage=142.545 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 4

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.5 Page No 286"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "f=50.0\n",

-      "R=10.0\n",

-      "a=60.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_m=(math.sqrt(2)*V_s)\n",

-      "V_o=V_m/(2*math.pi)*(1+math.cos(math.radians(a)))\n",

-      "I_o=V_o/R\n",

-      "V_or=(V_m/(2*math.sqrt(math.pi)))*math.sqrt((math.pi-a*math.pi/180)+.5*math.sin(math.radians(2*a)))\n",

-      "I_or=V_or/R\n",

-      "P_dc=V_o*I_o\n",

-      "P_ac=V_or*I_or\n",

-      "RE=P_dc/P_ac    \n",

-      "FF=V_or/V_o    \n",

-      "VRF=math.sqrt(FF**2-1)    \n",

-      "TUF=P_dc/(V_s*I_or)    \n",

-      "PIV=V_m    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"rectification efficiency=%.4f\" %RE)\n",

-      "print(\"form factor=%.3f\" %FF)\n",

-      "print(\"voltage ripple factor=%.4f\" %VRF)\n",

-      "print(\"t/f utilisation factor=%.4f\" %TUF)\n",

-      "print(\"PIV of thyristor=%.2f V\" %PIV)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rectification efficiency=0.2834\n",

-        "form factor=1.879\n",

-        "voltage ripple factor=1.5903\n",

-        "t/f utilisation factor=0.1797\n",

-        "PIV of thyristor=325.27 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 5

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.6 Page No 294"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=1000.0\n",

-      "fos=2.5     #factor of safety\n",

-      "I_TAV=40.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_m1=V/(2*fos)\n",

-      "P1=(2*V_m1/math.pi)*I_TAV    \n",

-      "V_m2=V/(fos)\n",

-      "P2=(2*V_m2/math.pi)*I_TAV    \n",

-      "\n",

-      "#Results\n",

-      "print(\"for mid pt convertor\")\n",

-      "print(\"power handled=%.3f kW\" %(P1/1000))\n",

-      "print(\"for bridge convertor\")\n",

-      "print(\"power handled=%.3f kW\" %(P2/1000))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for mid pt convertor\n",

-        "power handled=5.093 kW\n",

-        "for bridge convertor\n",

-        "power handled=10.186 kW\n"

-       ]

-      }

-     ],

-     "prompt_number": 6

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.7, Page No 297"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "R=.4\n",

-      "I_o=10\n",

-      "I_or=I_o\n",

-      "E=120.0\n",

-      "\n",

-      "#Calculations\n",

-      "a1=math.degrees(math.acos((E+I_o*R)*math.pi/(2*V_m)))\n",

-      "pf1=(E*I_o+I_or**2*R)/(V_s*I_or)    \n",

-      "E=-120.0\n",

-      "a2=math.degrees(math.acos((E+I_o*R)*math.pi/(2*V_m))) \n",

-      "pf2=(-E*I_o-I_or**2*R)/(V_s*I_or)   \n",

-      "\n",

-      "#Results\n",

-      "print(\"firing angle delay=%.2f deg\" %a1)\n",

-      "print(\"pf=%.4f\" %pf1)\n",

-      "print(\"firing angle delay=%.2f deg\" %a2)\n",

-      "print(\"pf=%.4f\" %pf2)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "firing angle delay=53.21 deg\n",

-        "pf=0.5391\n",

-        "firing angle delay=124.07 deg\n",

-        "pf=0.5043\n"

-       ]

-      }

-     ],

-     "prompt_number": 7

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.9 Page No 299"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "f=50.0\n",

-      "a=45.0\n",

-      "R=5.0\n",

-      "E=100.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_o=((math.sqrt(2)*V_s)/(2*math.pi))*(3+math.cos(math.radians(a)))\n",

-      "I_o=(V_o-E)/R    \n",

-      "P=E*I_o    \n",

-      "\n",

-      "#Results\n",

-      "print(\"avg o/p current=%.3f A\" %I_o)\n",

-      "print(\"power delivered to battery=%.4f kW\" %(P/1000))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "avg o/p current=18.382 A\n",

-        "power delivered to battery=1.8382 kW\n"

-       ]

-      }

-     ],

-     "prompt_number": 8

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.10 Page No 300"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variablesV_s=230\n",

-      "f=50.0\n",

-      "a=50.0\n",

-      "R=6.0\n",

-      "E=60.0\n",

-      "V_o1=((math.sqrt(2)*2*V_s)/(math.pi))*math.cos(math.radians(a))\n",

-      "I_o1=(V_o1-E)/R    \n",

-      "\n",

-      "#ATQ after applying the conditions\n",

-      "V_o2=((math.sqrt(2)*V_s)/(math.pi))*math.cos(math.radians(a))\n",

-      "I_o2=(V_o2-E)/R    \n",

-      "\n",

-      "print(\"avg o/p current=%.3f A\" %I_o1)\n",

-      "print(\"avg o/p current after change=%.2f A\" %I_o2)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "avg o/p current=12.184 A\n",

-        "avg o/p current after change=1.09 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 9

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.11 Page No 309"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "a=45.0\n",

-      "R=10.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_o=(2*V_m/math.pi)*math.cos(math.radians(a))\n",

-      "I_o=V_o/R\n",

-      "V_or=V_m/math.sqrt(2)\n",

-      "I_or=I_o\n",

-      "P_dc=V_o*I_o\n",

-      "P_ac=V_or*I_or\n",

-      "RE=P_dc/P_ac    \n",

-      "FF=V_or/V_o    \n",

-      "VRF=math.sqrt(FF**2-1)    \n",

-      "I_s1=2*math.sqrt(2)*I_o/math.pi\n",

-      "DF=math.cos(math.radians(a))\n",

-      "CDF=.90032\n",

-      "pf=CDF*DF    \n",

-      "HF=math.sqrt((1/CDF**2)-1)    \n",

-      "Q=2*V_m*I_o*math.sin(math.radians(a))/math.pi \n",

-      "\n",

-      "#Results\n",

-      "print(\"rectification efficiency=%.4f\" %RE)\n",

-      "print(\"form factor=%.4f\" %FF)\n",

-      "print(\"voltage ripple factor=%.4f\" %VRF)\n",

-      "print(\"pf=%.5f\" %pf)\n",

-      "print(\"HF=%.5f\" %HF)\n",

-      "print(\"active power=%.2f W\" %P_dc)   \n",

-      "print(\"reactive power=%.3f Var\" %Q)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rectification efficiency=0.6366\n",

-        "form factor=1.5708\n",

-        "voltage ripple factor=1.2114\n",

-        "pf=0.63662\n",

-        "HF=0.48342\n",

-        "active power=2143.96 W\n",

-        "reactive power=2143.956 Var\n"

-       ]

-      }

-     ],

-     "prompt_number": 10

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.12, Page No 310"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "a=45.0\n",

-      "R=10.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_o=(V_m/math.pi)*(1+math.cos(math.radians(a)))\n",

-      "I_o=V_o/R\n",

-      "V_or=V_s*math.sqrt((1/math.pi)*((math.pi-a*math.pi/180)+math.sin(math.radians(2*a))/2))\n",

-      "I_or=I_o\n",

-      "P_dc=V_o*I_o\n",

-      "P_ac=V_or*I_or\n",

-      "RE=P_dc/P_ac    \n",

-      "FF=V_or/V_o    \n",

-      "VRF=math.sqrt(FF**2-1)    \n",

-      "I_s1=2*math.sqrt(2)*I_o*math.cos(math.radians(a/2))/math.pi\n",

-      "DF=math.cos(math.radians(a/2))   \n",

-      "CDF=2*math.sqrt(2)*math.cos(math.radians(a/2))/math.sqrt(math.pi*(math.pi-a*math.pi/180))    \n",

-      "pf=CDF*DF    \n",

-      "HF=math.sqrt((1/CDF**2)-1)    \n",

-      "Q=V_m*I_o*math.sin(math.radians(a))/math.pi\n",

-      "\n",

-      "#Results\n",

-      "print(\"form factor=%.3f\" %FF)\n",

-      "print(\"rectification efficiency=%.4f\" %RE)\n",

-      "print(\"voltage ripple factor=%.3f\" %VRF)    \n",

-      "print(\"DF=%.4f\" %DF)\n",

-      "print(\"CDF=%.4f\" %CDF)\n",

-      "print(\"pf=%.4f\" %pf)\n",

-      "print(\"HF=%.4f\" %HF)\n",

-      "print(\"active power=%.3f W\" %P_dc)\n",

-      "print(\"reactive power=%.2f Var\" %Q)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "form factor=1.241\n",

-        "rectification efficiency=0.8059\n",

-        "voltage ripple factor=0.735\n",

-        "DF=0.9239\n",

-        "CDF=0.9605\n",

-        "pf=0.8874\n",

-        "HF=0.2899\n",

-        "active power=3123.973 W\n",

-        "reactive power=1293.99 Var\n"

-       ]

-      }

-     ],

-     "prompt_number": 11

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.13, Page No 319"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "R=10.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_ml=math.sqrt(2)*V_s\n",

-      "V_om=3*V_ml/(2*math.pi)\n",

-      "V_o=V_om/2\n",

-      "th=30\n",

-      "a=math.degrees(math.acos((2*math.pi*math.sqrt(3)*V_o/(3*V_ml)-1)))-th    \n",

-      "I_o=V_o/R    \n",

-      "V_or=V_ml/(2*math.sqrt(math.pi))*math.sqrt((5*math.pi/6-a*math.pi/180)+.5*math.sin(math.radians(2*a+2*th)))\n",

-      "I_or=V_or/R    \n",

-      "RE=V_o*I_o/(V_or*I_or)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"delay angle=%.1f deg\" %a)\n",

-      "print(\"avg load current=%.3f A\" %I_o)\n",

-      "print(\"rms load current=%.3f A\" %I_or)\n",

-      "print(\"rectification efficiency=%.4f\" %RE)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "delay angle=67.7 deg\n",

-        "avg load current=7.765 A\n",

-        "rms load current=10.477 A\n",

-        "rectification efficiency=0.5494\n"

-       ]

-      }

-     ],

-     "prompt_number": 12

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.15, Page No 321"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=400.0\n",

-      "V_ml=math.sqrt(2)*V\n",

-      "v_T=1.4\n",

-      "a1=30.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_o1=3*V_ml/(2*math.pi)*math.cos(math.radians(a1))-v_T   \n",

-      "a2=60.0\n",

-      "V_o2=3*V_ml/(2*math.pi)*math.cos(math.radians(a2))-v_T  \n",

-      "I_o=36\n",

-      "I_TA=I_o/3    \n",

-      "I_Tr=I_o/math.sqrt(3)    \n",

-      "P=I_TA*v_T       \n",

-      "\n",

-      "#Results\n",

-      "print(\"for firing angle = 30deg\")\n",

-      "print(\"avg output voltage=%.3f V\" %V_o1)\n",

-      "print(\"for firing angle = 60deg\")\n",

-      "print(\"avg output voltage=%.2f V\" %V_o2)\n",

-      "print(\"avg current rating=%.0f A\" %I_TA)\n",

-      "print(\"rms current rating=%.3f A\" %I_Tr)\n",

-      "print(\"PIV of SCR=%.1f V\" %V_ml)\n",

-      "print(\"power dissipated=%.1f W\" %P)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for firing angle = 30deg\n",

-        "avg output voltage=232.509 V\n",

-        "for firing angle = 60deg\n",

-        "avg output voltage=133.65 V\n",

-        "avg current rating=12 A\n",

-        "rms current rating=20.785 A\n",

-        "PIV of SCR=565.7 V\n",

-        "power dissipated=16.8 W\n"

-       ]

-      }

-     ],

-     "prompt_number": 13

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.17, Page No 331"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "E=200\n",

-      "I_o=20\n",

-      "R=.5\n",

-      "\n",

-      "#Calculations\n",

-      "V_o1=E+I_o*R\n",

-      "V_s=230\n",

-      "V_ml=math.sqrt(2)*V_s\n",

-      "a1=math.degrees(math.acos(V_o1*math.pi/(3*V_ml)))\n",

-      "th=120\n",

-      "I_s=math.sqrt((1/math.pi)*I_o**2*th*math.pi/180)\n",

-      "P=E*I_o+I_o**2*R\n",

-      "pf=P/(math.sqrt(3)*V_s*I_s)    \n",

-      "V_o2=E-I_o*R\n",

-      "a2=math.degrees(math.acos(-V_o2*math.pi/(3*V_ml))) \n",

-      "\n",

-      "#Results\n",

-      "print(\"firing angle delay=%.3f deg\" %a1)\n",

-      "print(\"pf=%.3f\" %pf)\n",

-      "print(\"firing angle delay=%.2f deg\" %a2)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "firing angle delay=47.461 deg\n",

-        "pf=0.646\n",

-        "firing angle delay=127.71 deg\n"

-       ]

-      }

-     ],

-     "prompt_number": 14

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.18, Page No 332"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=230.0\n",

-      "f=50.0\n",

-      "\n",

-      "#Calculations\n",

-      "w=2*math.pi*f\n",

-      "a1=0\n",

-      "t_c1=(4*math.pi/3-a1*math.pi/180)/w    \n",

-      "a2=30\n",

-      "t_c2=(4*math.pi/3-a2*math.pi/180)/w    \n",

-      "\n",

-      "#Results\n",

-      "print(\"for firing angle delay=0deg\")\n",

-      "print(\"commutation time=%.2f ms\" %(t_c1*1000))\n",

-      "print(\"peak reverse voltage=%.2f V\" %(math.sqrt(2)*V))\n",

-      "print(\"for firing angle delay=30deg\")\n",

-      "print(\"commutation time=%.2f ms\" %(t_c2*1000))\n",

-      "print(\"peak reverse voltage=%.2f V\" %(math.sqrt(2)*V))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for firing angle delay=0deg\n",

-        "commutation time=13.33 ms\n",

-        "peak reverse voltage=325.27 V\n",

-        "for firing angle delay=30deg\n",

-        "commutation time=11.67 ms\n",

-        "peak reverse voltage=325.27 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 15

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.19, Page No 333"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "a=30.0\n",

-      "R=10.0\n",

-      "P=5000.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_s=math.sqrt(P*R*2*math.pi/(2*3)/(math.pi/3+math.sqrt(3)*math.cos(math.radians(2*a))/2))\n",

-      "V_ph=V_s/math.sqrt(3)    \n",

-      "I_or=math.sqrt(P*R)\n",

-      "V_s=I_or*math.pi/(math.sqrt(2)*3*math.cos(math.radians(a)))\n",

-      "V_ph=V_s/math.sqrt(3) \n",

-      "\n",

-      "#Results\n",

-      "print(\"per phase voltage percent V_ph=%.3f V\" %V_ph)   \n",

-      "print(\"for constant load current\")\n",

-      "print(\"V_ph=%.2f V\" %V_ph)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "per phase voltage percent V_ph=110.384 V\n",

-        "for constant load current\n",

-        "V_ph=110.38 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 16

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.20, Page No 334"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "a=30.0\n",

-      "R=10.0\n",

-      "P=5000.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_s=math.sqrt(P*R*4*math.pi/(2*3)/(2*math.pi/3+math.sqrt(3)*(1+math.cos(math.radians(2*a)))/2))\n",

-      "V_ph=V_s/math.sqrt(3)    \n",

-      "I_or=math.sqrt(P*R)\n",

-      "V_s=I_or*2*math.pi/(math.sqrt(2)*3*(1+math.cos(math.radians(a))))\n",

-      "V_ph=V_s/math.sqrt(3)   \n",

-      "\n",

-      "#Results\n",

-      "print(\"per phase voltage percent V_ph=%.3f V\" %V_ph) \n",

-      "print(\"for constant load current\")\n",

-      "print(\"V_ph=%.2f V\" %V_ph)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "per phase voltage percent V_ph=102.459 V\n",

-        "for constant load current\n",

-        "V_ph=102.46 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 17

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.21, Page No 334"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "a=90.0\n",

-      "R=10.0\n",

-      "P=5000.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_s=math.sqrt(P*R*4*math.pi/(2*3)/((math.pi-math.pi/2)+(math.sin(math.radians(2*a)))/2))\n",

-      "V_ph=V_s/math.sqrt(3)    \n",

-      "I_or=math.sqrt(P*R)\n",

-      "V_s=I_or*2*math.pi/(math.sqrt(2)*3*(1+math.cos(math.radians(a))))\n",

-      "V_ph=V_s/math.sqrt(3)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"per phase voltage percent V_ph=%.2f V\" %V_ph)\n",

-      "print(\"for constant load current\")\n",

-      "print(\"V_ph=%.1f V\" %V_ph)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "per phase voltage percent V_ph=191.19 V\n",

-        "for constant load current\n",

-        "V_ph=191.2 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 18

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.22 Page No 334"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "E=200.0\n",

-      "I_o=20.0\n",

-      "R=.5\n",

-      "\n",

-      "#Calculations\n",

-      "V_o=E+I_o*R\n",

-      "V_s=230\n",

-      "V_ml=math.sqrt(2)*V_s\n",

-      "a=math.degrees(math.acos(V_o*2*math.pi/(3*V_ml)-1))  \n",

-      "a1=180-a\n",

-      "I_sr=math.sqrt((1/math.pi)*I_o**2*(a1*math.pi/180))\n",

-      "P=V_o*I_o\n",

-      "pf=P/(math.sqrt(3)*V_s*I_sr)   \n",

-      "\n",

-      "#Results\n",

-      "print(\"firing angle delay=%.2f deg\" %a)\n",

-      "print(\"pf=%.2f\" %pf)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "firing angle delay=69.38 deg\n",

-        "pf=0.67\n"

-       ]

-      }

-     ],

-     "prompt_number": 19

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.23, Page No 335"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=400.0\n",

-      "f=50.0\n",

-      "I_o=15.0\n",

-      "a=45.0\n",

-      "\n",

-      "#Calculations\n",

-      "I_TA=I_o*120.0/360.0\n",

-      "I_Tr=math.sqrt(I_o**2*120/360)\n",

-      "I_sr=math.sqrt(I_o**2*120/180)\n",

-      "V_ml=math.sqrt(2)*V_s\n",

-      "V_o=3*V_ml*math.cos(math.radians(a))/math.pi\n",

-      "V_or=V_ml*math.sqrt((3/(2*math.pi))*(math.pi/3+math.sqrt(3/2)*math.cos(math.radians(2*a))))\n",

-      "I_or=I_o\n",

-      "P_dc=V_o*I_o\n",

-      "P_ac=V_or*I_or\n",

-      "RE=P_dc/P_ac    \n",

-      "VA=3*V_s/math.sqrt(3)*I_sr\n",

-      "TUF=P_dc/VA    \n",

-      "pf=P_ac/VA    \n",

-      "\n",

-      "#Results\n",

-      "print(\"rectification efficiency=%.5f\" %RE)\n",

-      "print(\"TUF=%.4f\" %TUF)\n",

-      "print(\"Input pf=%.3f\" %pf)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rectification efficiency=0.95493\n",

-        "TUF=0.6752\n",

-        "Input pf=0.707\n"

-       ]

-      }

-     ],

-     "prompt_number": 20

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.24, Page No 341"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "I=10.0\n",

-      "a=45.0\n",

-      "V=400.0\n",

-      "f=50.0\n",

-      "\n",

-      "#Calculations\n",

-      "DF=math.cos(math.radians(a))\n",

-      "I_o=10\n",

-      "I_s1=4*I_o/(math.sqrt(2)*math.pi)*math.sin(math.pi/3)\n",

-      "I_sr=I_o*math.sqrt(2.0/3.0)\n",

-      "I_o=1     #suppose\n",

-      "CDF=I_s1/I_sr    \n",

-      "THD=math.sqrt(1/CDF**2-1)    \n",

-      "pf=CDF*DF    \n",

-      "P=(3*math.sqrt(2)*V*math.cos(math.radians(a))/math.pi)*I\n",

-      "Q=(3*math.sqrt(2)*V*math.sin(math.radians(a))/math.pi)*I  \n",

-      "   \n",

-      "#Results\n",

-      "print(\"DF=%.3f\" %DF)\n",

-      "print(\"CDF=%.3f\" %CDF)\n",

-      "print(\"THD=%.5f\" %THD)\n",

-      "print(\"PF=%.4f\" %pf)\n",

-      "print(\"active power=%.2f W\" %P)  \n",

-      "print(\"reactive power=%.2f Var\" %Q)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "DF=0.707\n",

-        "CDF=0.955\n",

-        "THD=0.31084\n",

-        "PF=0.6752\n",

-        "active power=3819.72 W\n",

-        "reactive power=3819.72 Var\n"

-       ]

-      }

-     ],

-     "prompt_number": 21

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.25, Page No 342"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "print(\"for firing angle=30deg\")\n",

-      "a=30.0\n",

-      "V=400.0\n",

-      "V_ml=math.sqrt(2)*V\n",

-      "V_o=3*V_ml*math.cos(math.radians(a))/math.pi\n",

-      "E=350\n",

-      "R=10\n",

-      "\n",

-      "#Calculations\n",

-      "I_o=(V_o-E)/R\n",

-      "I_or=I_o\n",

-      "P1=V_o*I_o    \n",

-      "I_sr=I_o*math.sqrt(2.0/3.0)\n",

-      "VA=3*V/math.sqrt(3)*I_sr\n",

-      "pf=P1/VA \n",

-      "a=180-60\n",

-      "V=400\n",

-      "V_ml=math.sqrt(2)*V\n",

-      "V_o=3*V_ml*math.cos(math.radians(a))/math.pi\n",

-      "E=-350\n",

-      "R=10\n",

-      "I_o=(V_o-E)/R\n",

-      "I_or=I_o\n",

-      "P2=-V_o*I_o    \n",

-      "I_sr=I_o*math.sqrt(2.0/3.0)\n",

-      "VA=3*V/math.sqrt(3)*I_sr\n",

-      "pf=P2/VA       \n",

-      "\n",

-      "print(\"power delivered to load=%.2f W\" %P1)\n",

-      "print(\"pf=%.4f\" %pf)\n",

-      "print(\"for firing advance angle=60deg\")\n",

-      "print(\"power delivered to load=%.2f W\" %P2)\n",

-      "print(\"pf=%.4f\" %pf)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits.\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for firing angle=30deg\n",

-        "power delivered to load=5511.74 W\n",

-        "pf=0.4775\n",

-        "for firing advance angle=60deg\n",

-        "power delivered to load=2158.20 W\n",

-        "pf=0.4775\n"

-       ]

-      }

-     ],

-     "prompt_number": 22

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.26, Page No 347"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "a=0\n",

-      "u=15.0\n",

-      "\n",

-      "#Calculations\n",

-      "i=math.cos(math.radians(a))-math.cos(math.radians(a+u))\n",

-      "a=30\n",

-      "u=math.degrees(math.acos(math.cos(math.radians(a))-i))-a  \n",

-      "a=45\n",

-      "u=math.degrees(math.acos(math.cos(math.radians(a))-i))-a    \n",

-      "a=60\n",

-      "u=math.degrees(math.acos(math.cos(math.radians(a))-i))-a  \n",

-      "\n",

-      "#Results\n",

-      "print(\"for firing angle=30deg\") \n",

-      "print(\"overlap angle=%.1f deg\" %u)\n",

-      "print(\"for firing angle=45deg\")  \n",

-      "print(\"overlap angle=%.1f deg\" %u)\n",

-      "print(\"for firing angle=60deg\") \n",

-      "print(\"overlap angle=%.2f deg\" %u)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for firing angle=30deg\n",

-        "overlap angle=2.2 deg\n",

-        "for firing angle=45deg\n",

-        "overlap angle=2.2 deg\n",

-        "for firing angle=60deg\n",

-        "overlap angle=2.23 deg\n"

-       ]

-      }

-     ],

-     "prompt_number": 23

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.28, Page No 352"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "E=400.0\n",

-      "I_o=20.0\n",

-      "R=1\n",

-      "\n",

-      "#Calculations\n",

-      "V_o=E+I_o*R\n",

-      "f=50.0\n",

-      "w=2*math.pi*f\n",

-      "L=.004\n",

-      "V=230 #per phase voltage\n",

-      "V_ml=math.sqrt(6)*V\n",

-      "a=math.degrees(math.acos(math.pi/(3*V_ml)*(V_o+3*w*L*I_o/math.pi)))   \n",

-      "print(\"firing angle delay=%.3f deg\" %a)\n",

-      "u=math.degrees(math.acos(math.pi/(3*V_ml)*(V_o-3*w*L*I_o/math.pi)))-a    \n",

-      "\n",

-      "#Results\n",

-      "print(\"overlap angle=%.2f deg\" %u)\n",

-      "#Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "firing angle delay=34.382 deg\n",

-        "overlap angle=8.22 deg\n"

-       ]

-      }

-     ],

-     "prompt_number": 24

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.29, Page No 352"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=400.0\n",

-      "f=50.0\n",

-      "w=2*math.pi*f\n",

-      "R=1\n",

-      "E=230\n",

-      "I=15.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_o=-E+I*R\n",

-      "V_ml=math.sqrt(2)*V\n",

-      "a=math.degrees(math.acos(V_o*2*math.pi/(3*V_ml)))  \n",

-      "L=0.004\n",

-      "a=math.degrees(math.acos((2*math.pi)/(3*V_ml)*(V_o+3*w*L*I/(2*math.pi))))  \n",

-      "u=math.degrees(math.acos(math.cos(math.radians(a))-3*f*L*I/V_ml))-a    \n",

-      "\n",

-      "#Results\n",

-      "print(\"firing angle=%.3f deg\" %a)\n",

-      "print(\"firing angle delay=%.3f deg\" %a)\n",

-      "print(\"overlap angle=%.3f deg\" %u)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits.\n",

-      " \n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "firing angle=139.702 deg\n",

-        "firing angle delay=139.702 deg\n",

-        "overlap angle=1.431 deg\n"

-       ]

-      }

-     ],

-     "prompt_number": 25

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.31, Page No 361"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=230.0 #per phase\n",

-      "f=50.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_ml=math.sqrt(3.0)*math.sqrt(2)*V\n",

-      "w=2*math.pi*f\n",

-      "a1=60.0\n",

-      "L=0.015\n",

-      "i_cp=(math.sqrt(3)*V_ml/(w*L))*(1-math.sin(math.radians(a1)))    \n",

-      "\n",

-      "#Results\n",

-      "print(\"circulating current=%.4f A\" %i_cp)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "circulating current=27.7425 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 26

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.32, Page No 362"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=230.0\n",

-      "V_m=math.sqrt(2)*V\n",

-      "a=30.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_o=2*V_m* math.cos(math.radians(a))/math.pi    \n",

-      "R=10\n",

-      "I_o=V_o/R    \n",

-      "I_TA=I_o*math.pi/(2*math.pi)    \n",

-      "I_Tr=math.sqrt(I_o**2*math.pi/(2*math.pi))    \n",

-      "I_s=math.sqrt(I_o**2*math.pi/(math.pi)) \n",

-      "I_o=I_s\n",

-      "pf=(V_o*I_o/(V*I_s))    \n",

-      "\n",

-      "#Results\n",

-      "print(\"avg o/p voltage=%.3f V\" %V_o)\n",

-      "print(\"avg o/p current=%.2f A\" %I_o)\n",

-      "print(\"avg value of thyristor current=%.3f A\" %I_TA)\n",

-      "print(\"rms value of thyristor current=%.2f A\" %I_Tr)\n",

-      "print(\"pf=%.4f\" %pf)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits.\n",

-      " \n",

-      " \n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "avg o/p voltage=179.330 V\n",

-        "avg o/p current=17.93 A\n",

-        "avg value of thyristor current=8.967 A\n",

-        "rms value of thyristor current=12.68 A\n",

-        "pf=0.7797\n"

-       ]

-      }

-     ],

-     "prompt_number": 27

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.33, Page No 363"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=230.0\n",

-      "V_m=math.sqrt(2)*V\n",

-      "a=30.0\n",

-      "L=.0015\n",

-      "\n",

-      "#Calculations\n",

-      "V_o=2*V_m* math.cos(math.radians(a))/math.pi  \n",

-      "R=10\n",

-      "I_o=V_o/R  \n",

-      "f=50\n",

-      "w=2*math.pi*f\n",

-      "V_ox=2*V_m*math.cos(math.radians(a))/math.pi-w*L*I_o/math.pi    \n",

-      "u=math.degrees(math.acos(math.cos(math.radians(a))-I_o*w*L/V_m))-a    \n",

-      "I=I_o\n",

-      "pf=V_o*I_o/(V*I)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"avg o/p voltage=%.3f V\" %V_ox)\n",

-      "print(\"angle of overlap=%.3f deg\" %u)\n",

-      "print(\"pf=%.4f\" %pf)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "avg o/p voltage=176.640 V\n",

-        "angle of overlap=2.855 deg\n",

-        "pf=0.7797\n"

-       ]

-      }

-     ],

-     "prompt_number": 28

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.34, Page No 364"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=415.0\n",

-      "V_ml=math.sqrt(2)*V\n",

-      "a1=35.0 #firing angle advance\n",

-      "\n",

-      "#Calculations\n",

-      "a=180-a1\n",

-      "I_o=80.0\n",

-      "r_s=0.04\n",

-      "v_T=1.5\n",

-      "X_l=.25 #reactance=w*L\n",

-      "E=-3*V_ml*math.cos(math.radians(a))/math.pi+2*I_o*r_s+2*v_T+3*X_l*I_o/math.pi    \n",

-      "\n",

-      "#Results\n",

-      "print(\"mean generator voltage=%.3f V\" %E)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "mean generator voltage=487.590 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 29

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.35, Page No 364"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=415.0\n",

-      "V_ml=math.sqrt(2)*V\n",

-      "R=0.2\n",

-      "I_o=80\n",

-      "r_s=0.04\n",

-      "v_T=1.5\n",

-      "\n",

-      "#Calculations\n",

-      "X_l=.25 #reactance=w*L\n",

-      "a=35\n",

-      "E=-(-3*V_ml*math.cos(math.radians(a))/math.pi+I_o*R+2*I_o*r_s+2*v_T+3*X_l*I_o/math.pi)    \n",

-      "a1=35\n",

-      "a=180-a1\n",

-      "E=(-3*V_ml*math.cos(math.radians(a))/math.pi+I_o*R+2*I_o*r_s+2*v_T+3*X_l*I_o/math.pi) \n",

-      "\n",

-      "#Results\n",

-      "print(\"when firing angle=35deg\")   \n",

-      "print(\"mean generator voltage=%.3f V\" %E)\n",

-      "print(\"when firing angle advance=35deg\")\n",

-      "print(\"mean generator voltage=%.3f V\" %E)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "when firing angle=35deg\n",

-        "mean generator voltage=503.590 V\n",

-        "when firing angle advance=35deg\n",

-        "mean generator voltage=503.590 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 30

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.36, Page No 365"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "R=5.0\n",

-      "V=230.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_mp=math.sqrt(2)*V\n",

-      "a=30.0\n",

-      "E=150.0\n",

-      "B=180-math.degrees(math.asin(E/V_mp))\n",

-      "I_o=(3/(2*math.pi*R))*(V_mp*(math.cos(math.radians(a+30))-math.cos(math.radians(B)))-E*((B-a-30)*math.pi/180))\n",

-      "\n",

-      "#Results\n",

-      "print(\"avg current flowing=%.2f A\" %I_o)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "avg current flowing=19.96 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 31

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.37, Page No 366"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "a=30.0\n",

-      "V=230.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_m=math.sqrt(2)*V\n",

-      "V_o=V_m*(1+math.cos(math.radians(a)))/math.pi    \n",

-      "E=100\n",

-      "R=10\n",

-      "I_o=(V_o-E)/R    \n",

-      "I_TA=I_o*math.pi/(2*math.pi)    \n",

-      "I_Tr=math.sqrt(I_o**2*math.pi/(2*math.pi))    \n",

-      "I_s=math.sqrt(I_o**2*(1-a/180)*math.pi/(math.pi))\n",

-      "I_or=I_o\n",

-      "P=E*I_o+I_or**2*R\n",

-      "pf=(P/(V*I_s))   \n",

-      "f=50\n",

-      "w=2*math.pi*f\n",

-      "t_c=(1-a/180)*math.pi/w    \n",

-      "\n",

-      "#Results\n",

-      "print(\"\\navg o/p current=%.2f A\" %I_o)\n",

-      "print(\"avg o/p voltage=%.3f V\" %V_o)\n",

-      "print(\"avg value of thyristor current=%.2f A\" %I_TA)\n",

-      "print(\"rms value of thyristor current=%.3f A\" %I_Tr)\n",

-      "print(\"avg value of diode current=%.2f A\" %I_TA)\n",

-      "print(\"rms value of diode current=%.3f A\" %I_Tr)\n",

-      "print(\"pf=%.4f\" %pf)\n",

-      "print(\"circuit turn off time=%.2f ms\" %(t_c*1000))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "\n",

-        "avg o/p current=9.32 A\n",

-        "avg o/p voltage=193.202 V\n",

-        "avg value of thyristor current=4.66 A\n",

-        "rms value of thyristor current=6.590 A\n",

-        "avg value of diode current=4.66 A\n",

-        "rms value of diode current=6.590 A\n",

-        "pf=0.9202\n",

-        "circuit turn off time=8.33 ms\n"

-       ]

-      }

-     ],

-     "prompt_number": 32

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.38, Page No 368"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=230.0\n",

-      "V_m=math.sqrt(2)*V\n",

-      "L=0.05\n",

-      "f=50.0\n",

-      "\n",

-      "#Calculations\n",

-      "w=2*math.pi*f\n",

-      "a=30\n",

-      "i_cp=2*V_m*(1-math.cos(math.radians(a)))/(w*L)    \n",

-      "R=30.0\n",

-      "i_l=V_m/R\n",

-      "i1=i_cp+i_l    \n",

-      "i2=i_cp    \n",

-      "\n",

-      "#Results\n",

-      "print(\"peak value of circulating current=%.3f A\" %i_cp)\n",

-      "print(\"peak value of current in convertor 1=%.3f A\" %i1)\n",

-      "print(\"peak value of current in convertor 2=%.3f A\" %i2)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "peak value of circulating current=5.548 A\n",

-        "peak value of current in convertor 1=16.391 A\n",

-        "peak value of current in convertor 2=5.548 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 33

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.39, Page No 370"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "f=50.0\n",

-      "w=2*math.pi*f\n",

-      "R=5.0\n",

-      "L=0.05\n",

-      "\n",

-      "#Calculations\n",

-      "phi=math.degrees(math.atan(w*L/R))  \n",

-      "phi=90+math.degrees(math.atan(w*L/R))   \n",

-      "\n",

-      "#Results\n",

-      "print(\"for no current transients\")\n",

-      "print(\"triggering angle=%.2f deg\" %phi)\n",

-      "print(\"for worst transients\")\n",

-      "print(\"triggering angle=%.2f deg\" %phi)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for no current transients\n",

-        "triggering angle=162.34 deg\n",

-        "for worst transients\n",

-        "triggering angle=162.34 deg\n"

-       ]

-      }

-     ],

-     "prompt_number": 34

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Power_Electronics/Chapter6_3.ipynb b/_Power_Electronics/Chapter6_3.ipynb
deleted file mode 100755
index dff6564b..00000000
--- a/_Power_Electronics/Chapter6_3.ipynb
+++ /dev/null
@@ -1,1761 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 06 : Phase Controlled Rectifiers"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.1, Page No 283"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=230.0\n",

-      "P=1000.0\n",

-      "R=V**2/P\n",

-      "\n",

-      "#Calculations\n",

-      "a=math.pi/4\n",

-      "V_or1=(math.sqrt(2)*V/(2*math.sqrt(math.pi)))*math.sqrt((math.pi-a)+.5*math.sin(2*a))\n",

-      "P1=V_or1**2/R    \n",

-      "a=math.pi/2\n",

-      "V_or2=(math.sqrt(2)*V/(2*math.sqrt(math.pi)))*math.sqrt((math.pi-a)+.5*math.sin(2*a))\n",

-      "P2=V_or2**2/R   \n",

-      "\n",

-      "#Results\n",

-      "print(\"when firing angle delay is of 45deg\")\n",

-      "print(\"power absorbed=%.2f W\" %P1)\n",

-      "print(\"when firing angle delay is of 90deg\")\n",

-      "print(\"power absorbed=%.2f W\" %P2)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "when firing angle delay is of 45deg\n",

-        "power absorbed=454.58 W\n",

-        "when firing angle delay is of 90deg\n",

-        "power absorbed=250.00 W\n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.2, Page No 283"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=230.0\n",

-      "E=150.0\n",

-      "R=8.0\n",

-      "\n",

-      "#Calculations\n",

-      "th1=math.sin(math.radians(E/(math.sqrt(2)*V)))\n",

-      "I_o=(1/(2*math.pi*R))*(2*math.sqrt(2)*230*math.cos(math.radians(th1))-E*(math.pi-2*th1*math.pi/180))    \n",

-      "P=E*I_o    \n",

-      "I_or=math.sqrt((1/(2*math.pi*R**2))*((V**2+E**2)*(math.pi-2*th1*math.pi/180)+V**2*math.sin(math.radians(2*th1))-4*math.sqrt(2)*V*E*math.cos(math.radians(th1))))\n",

-      "P_r=I_or**2*R    \n",

-      "pf=(P+P_r)/(V*I_or)\n",

-      "\n",

-      "#Results\n",

-      "print(\"avg charging curent=%.4f A\" %I_o)\n",

-      "print(\"power supplied to the battery=%.2f W\" %P)\n",

-      "print(\"power dissipated by the resistor=%.3f W\" %P_r)    \n",

-      "print(\"supply pf=%.3f\" %pf)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "avg charging curent=3.5679 A\n",

-        "power supplied to the battery=535.18 W\n",

-        "power dissipated by the resistor=829.760 W\n",

-        "supply pf=0.583\n"

-       ]

-      }

-     ],

-     "prompt_number": 2

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.3 Page No 284"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=230.0\n",

-      "E=150.0\n",

-      "R=8.0\n",

-      "a=35.0\n",

-      "\n",

-      "#Calculations\n",

-      "th1=math.degrees(math.asin(E/(math.sqrt(2)*V)))\n",

-      "th2=180-th1\n",

-      "I_o=(1/(2*math.pi*R))*(math.sqrt(2)*230*(math.cos(math.radians(a))-math.cos(math.radians(th2)))-E*((th2-a)*math.pi/180))    \n",

-      "P=E*I_o    \n",

-      "I_or=math.sqrt((1/(2*math.pi*R**2))*((V**2+E**2)*((th2-a)*math.pi/180)-(V**2/2)*(math.sin(math.radians(2*th2))-math.sin(math.radians(2*a)))-2*math.sqrt(2)*V*E*(math.cos(math.radians(a))-math.cos(math.radians(th2)))))\n",

-      "P_r=I_or**2*R    \n",

-      "pf=(P+P_r)/(V*I_or)    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"avg charging curent=%.4f A\" %I_o)\n",

-      "print(\"power supplied to the battery=%.2f W\" %P)\n",

-      "print(\"power dissipated by the resistor=%.2f W\" %P_r)\n",

-      "print(\"supply pf=%.4f\" %pf)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "avg charging curent=4.9208 A\n",

-        "power supplied to the battery=738.12 W\n",

-        "power dissipated by the resistor=689.54 W\n",

-        "supply pf=0.6686\n"

-       ]

-      }

-     ],

-     "prompt_number": 3

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.4, Page No 285"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "B=210\n",

-      "f=50.0     #Hz\n",

-      "w=2*math.pi*f\n",

-      "a=40.0     #firing angle\n",

-      "V=230.0\n",

-      "R=5.0\n",

-      "L=2*10**-3\n",

-      "\n",

-      "#Calculations\n",

-      "t_c1=(360-B)*math.pi/(180*w)   \n",

-      "V_o1=(math.sqrt(2)*230/(2*math.pi))*(math.cos(math.radians(a))-math.cos(math.radians(B)))    \n",

-      "I_o1=V_o1/R    \n",

-      "E=110\n",

-      "R=5\n",

-      "L=2*10**-3\n",

-      "th1=math.degrees(math.asin(E/(math.sqrt(2)*V)))\n",

-      "t_c2=(360-B+th1)*math.pi/(180*w)    \n",

-      "V_o2=(math.sqrt(2)*230/(2*math.pi))*(math.cos(math.radians(a))-math.cos(math.radians(B)))    \n",

-      "I_o2=(1/(2*math.pi*R))*(math.sqrt(2)*230*(math.cos(math.radians(a))-math.cos(math.radians(B)))-E*((B-a)*math.pi/180))   \n",

-      "V_o2=R*I_o2+E    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"for R=5ohm and L=2mH\")\n",

-      "print(\"ckt turn off time=%.3f msec\" %(t_c1*1000))\n",

-      "print(\"avg output voltage=%.3f V\" %V_o1)\n",

-      "print(\"avg output current=%.4f A\" %I_o1)\n",

-      "print(\"for R=5ohm % L=2mH and E=110V\")\n",

-      "print(\"ckt turn off time=%.3f msec\" %(t_c2*1000))\n",

-      "print(\"avg output current=%.4f A\" %I_o2)\n",

-      "print(\"avg output voltage=%.3f V\" %V_o2)   "

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for R=5ohm and L=2mH\n",

-        "ckt turn off time=8.333 msec\n",

-        "avg output voltage=84.489 V\n",

-        "avg output current=16.8979 A\n",

-        "for R=5ohm % L=2mH and E=110V\n",

-        "ckt turn off time=9.431 msec\n",

-        "avg output current=6.5090 A\n",

-        "avg output voltage=142.545 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 4

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.5 Page No 286"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "f=50.0\n",

-      "R=10.0\n",

-      "a=60.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_m=(math.sqrt(2)*V_s)\n",

-      "V_o=V_m/(2*math.pi)*(1+math.cos(math.radians(a)))\n",

-      "I_o=V_o/R\n",

-      "V_or=(V_m/(2*math.sqrt(math.pi)))*math.sqrt((math.pi-a*math.pi/180)+.5*math.sin(math.radians(2*a)))\n",

-      "I_or=V_or/R\n",

-      "P_dc=V_o*I_o\n",

-      "P_ac=V_or*I_or\n",

-      "RE=P_dc/P_ac    \n",

-      "FF=V_or/V_o    \n",

-      "VRF=math.sqrt(FF**2-1)    \n",

-      "TUF=P_dc/(V_s*I_or)    \n",

-      "PIV=V_m    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"rectification efficiency=%.4f\" %RE)\n",

-      "print(\"form factor=%.3f\" %FF)\n",

-      "print(\"voltage ripple factor=%.4f\" %VRF)\n",

-      "print(\"t/f utilisation factor=%.4f\" %TUF)\n",

-      "print(\"PIV of thyristor=%.2f V\" %PIV)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rectification efficiency=0.2834\n",

-        "form factor=1.879\n",

-        "voltage ripple factor=1.5903\n",

-        "t/f utilisation factor=0.1797\n",

-        "PIV of thyristor=325.27 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 5

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.6 Page No 294"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=1000.0\n",

-      "fos=2.5     #factor of safety\n",

-      "I_TAV=40.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_m1=V/(2*fos)\n",

-      "P1=(2*V_m1/math.pi)*I_TAV    \n",

-      "V_m2=V/(fos)\n",

-      "P2=(2*V_m2/math.pi)*I_TAV    \n",

-      "\n",

-      "#Results\n",

-      "print(\"for mid pt convertor\")\n",

-      "print(\"power handled=%.3f kW\" %(P1/1000))\n",

-      "print(\"for bridge convertor\")\n",

-      "print(\"power handled=%.3f kW\" %(P2/1000))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for mid pt convertor\n",

-        "power handled=5.093 kW\n",

-        "for bridge convertor\n",

-        "power handled=10.186 kW\n"

-       ]

-      }

-     ],

-     "prompt_number": 6

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.7, Page No 297"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "R=.4\n",

-      "I_o=10\n",

-      "I_or=I_o\n",

-      "E=120.0\n",

-      "\n",

-      "#Calculations\n",

-      "a1=math.degrees(math.acos((E+I_o*R)*math.pi/(2*V_m)))\n",

-      "pf1=(E*I_o+I_or**2*R)/(V_s*I_or)    \n",

-      "E=-120.0\n",

-      "a2=math.degrees(math.acos((E+I_o*R)*math.pi/(2*V_m))) \n",

-      "pf2=(-E*I_o-I_or**2*R)/(V_s*I_or)   \n",

-      "\n",

-      "#Results\n",

-      "print(\"firing angle delay=%.2f deg\" %a1)\n",

-      "print(\"pf=%.4f\" %pf1)\n",

-      "print(\"firing angle delay=%.2f deg\" %a2)\n",

-      "print(\"pf=%.4f\" %pf2)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "firing angle delay=53.21 deg\n",

-        "pf=0.5391\n",

-        "firing angle delay=124.07 deg\n",

-        "pf=0.5043\n"

-       ]

-      }

-     ],

-     "prompt_number": 7

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.9 Page No 299"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "f=50.0\n",

-      "a=45.0\n",

-      "R=5.0\n",

-      "E=100.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_o=((math.sqrt(2)*V_s)/(2*math.pi))*(3+math.cos(math.radians(a)))\n",

-      "I_o=(V_o-E)/R    \n",

-      "P=E*I_o    \n",

-      "\n",

-      "#Results\n",

-      "print(\"avg o/p current=%.3f A\" %I_o)\n",

-      "print(\"power delivered to battery=%.4f kW\" %(P/1000))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "avg o/p current=18.382 A\n",

-        "power delivered to battery=1.8382 kW\n"

-       ]

-      }

-     ],

-     "prompt_number": 8

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.10 Page No 300"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variablesV_s=230\n",

-      "f=50.0\n",

-      "a=50.0\n",

-      "R=6.0\n",

-      "E=60.0\n",

-      "V_o1=((math.sqrt(2)*2*V_s)/(math.pi))*math.cos(math.radians(a))\n",

-      "I_o1=(V_o1-E)/R    \n",

-      "\n",

-      "#ATQ after applying the conditions\n",

-      "V_o2=((math.sqrt(2)*V_s)/(math.pi))*math.cos(math.radians(a))\n",

-      "I_o2=(V_o2-E)/R    \n",

-      "\n",

-      "print(\"avg o/p current=%.3f A\" %I_o1)\n",

-      "print(\"avg o/p current after change=%.2f A\" %I_o2)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "avg o/p current=12.184 A\n",

-        "avg o/p current after change=1.09 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 9

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.11 Page No 309"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "a=45.0\n",

-      "R=10.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_o=(2*V_m/math.pi)*math.cos(math.radians(a))\n",

-      "I_o=V_o/R\n",

-      "V_or=V_m/math.sqrt(2)\n",

-      "I_or=I_o\n",

-      "P_dc=V_o*I_o\n",

-      "P_ac=V_or*I_or\n",

-      "RE=P_dc/P_ac    \n",

-      "FF=V_or/V_o    \n",

-      "VRF=math.sqrt(FF**2-1)    \n",

-      "I_s1=2*math.sqrt(2)*I_o/math.pi\n",

-      "DF=math.cos(math.radians(a))\n",

-      "CDF=.90032\n",

-      "pf=CDF*DF    \n",

-      "HF=math.sqrt((1/CDF**2)-1)    \n",

-      "Q=2*V_m*I_o*math.sin(math.radians(a))/math.pi \n",

-      "\n",

-      "#Results\n",

-      "print(\"rectification efficiency=%.4f\" %RE)\n",

-      "print(\"form factor=%.4f\" %FF)\n",

-      "print(\"voltage ripple factor=%.4f\" %VRF)\n",

-      "print(\"pf=%.5f\" %pf)\n",

-      "print(\"HF=%.5f\" %HF)\n",

-      "print(\"active power=%.2f W\" %P_dc)   \n",

-      "print(\"reactive power=%.3f Var\" %Q)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rectification efficiency=0.6366\n",

-        "form factor=1.5708\n",

-        "voltage ripple factor=1.2114\n",

-        "pf=0.63662\n",

-        "HF=0.48342\n",

-        "active power=2143.96 W\n",

-        "reactive power=2143.956 Var\n"

-       ]

-      }

-     ],

-     "prompt_number": 10

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.12, Page No 310"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "a=45.0\n",

-      "R=10.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_o=(V_m/math.pi)*(1+math.cos(math.radians(a)))\n",

-      "I_o=V_o/R\n",

-      "V_or=V_s*math.sqrt((1/math.pi)*((math.pi-a*math.pi/180)+math.sin(math.radians(2*a))/2))\n",

-      "I_or=I_o\n",

-      "P_dc=V_o*I_o\n",

-      "P_ac=V_or*I_or\n",

-      "RE=P_dc/P_ac    \n",

-      "FF=V_or/V_o    \n",

-      "VRF=math.sqrt(FF**2-1)    \n",

-      "I_s1=2*math.sqrt(2)*I_o*math.cos(math.radians(a/2))/math.pi\n",

-      "DF=math.cos(math.radians(a/2))   \n",

-      "CDF=2*math.sqrt(2)*math.cos(math.radians(a/2))/math.sqrt(math.pi*(math.pi-a*math.pi/180))    \n",

-      "pf=CDF*DF    \n",

-      "HF=math.sqrt((1/CDF**2)-1)    \n",

-      "Q=V_m*I_o*math.sin(math.radians(a))/math.pi\n",

-      "\n",

-      "#Results\n",

-      "print(\"form factor=%.3f\" %FF)\n",

-      "print(\"rectification efficiency=%.4f\" %RE)\n",

-      "print(\"voltage ripple factor=%.3f\" %VRF)    \n",

-      "print(\"DF=%.4f\" %DF)\n",

-      "print(\"CDF=%.4f\" %CDF)\n",

-      "print(\"pf=%.4f\" %pf)\n",

-      "print(\"HF=%.4f\" %HF)\n",

-      "print(\"active power=%.3f W\" %P_dc)\n",

-      "print(\"reactive power=%.2f Var\" %Q)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "form factor=1.241\n",

-        "rectification efficiency=0.8059\n",

-        "voltage ripple factor=0.735\n",

-        "DF=0.9239\n",

-        "CDF=0.9605\n",

-        "pf=0.8874\n",

-        "HF=0.2899\n",

-        "active power=3123.973 W\n",

-        "reactive power=1293.99 Var\n"

-       ]

-      }

-     ],

-     "prompt_number": 11

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.13, Page No 319"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "R=10.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_ml=math.sqrt(2)*V_s\n",

-      "V_om=3*V_ml/(2*math.pi)\n",

-      "V_o=V_om/2\n",

-      "th=30\n",

-      "a=math.degrees(math.acos((2*math.pi*math.sqrt(3)*V_o/(3*V_ml)-1)))-th    \n",

-      "I_o=V_o/R    \n",

-      "V_or=V_ml/(2*math.sqrt(math.pi))*math.sqrt((5*math.pi/6-a*math.pi/180)+.5*math.sin(math.radians(2*a+2*th)))\n",

-      "I_or=V_or/R    \n",

-      "RE=V_o*I_o/(V_or*I_or)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"delay angle=%.1f deg\" %a)\n",

-      "print(\"avg load current=%.3f A\" %I_o)\n",

-      "print(\"rms load current=%.3f A\" %I_or)\n",

-      "print(\"rectification efficiency=%.4f\" %RE)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "delay angle=67.7 deg\n",

-        "avg load current=7.765 A\n",

-        "rms load current=10.477 A\n",

-        "rectification efficiency=0.5494\n"

-       ]

-      }

-     ],

-     "prompt_number": 12

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.15, Page No 321"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=400.0\n",

-      "V_ml=math.sqrt(2)*V\n",

-      "v_T=1.4\n",

-      "a1=30.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_o1=3*V_ml/(2*math.pi)*math.cos(math.radians(a1))-v_T   \n",

-      "a2=60.0\n",

-      "V_o2=3*V_ml/(2*math.pi)*math.cos(math.radians(a2))-v_T  \n",

-      "I_o=36\n",

-      "I_TA=I_o/3    \n",

-      "I_Tr=I_o/math.sqrt(3)    \n",

-      "P=I_TA*v_T       \n",

-      "\n",

-      "#Results\n",

-      "print(\"for firing angle = 30deg\")\n",

-      "print(\"avg output voltage=%.3f V\" %V_o1)\n",

-      "print(\"for firing angle = 60deg\")\n",

-      "print(\"avg output voltage=%.2f V\" %V_o2)\n",

-      "print(\"avg current rating=%.0f A\" %I_TA)\n",

-      "print(\"rms current rating=%.3f A\" %I_Tr)\n",

-      "print(\"PIV of SCR=%.1f V\" %V_ml)\n",

-      "print(\"power dissipated=%.1f W\" %P)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for firing angle = 30deg\n",

-        "avg output voltage=232.509 V\n",

-        "for firing angle = 60deg\n",

-        "avg output voltage=133.65 V\n",

-        "avg current rating=12 A\n",

-        "rms current rating=20.785 A\n",

-        "PIV of SCR=565.7 V\n",

-        "power dissipated=16.8 W\n"

-       ]

-      }

-     ],

-     "prompt_number": 13

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.17, Page No 331"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "E=200\n",

-      "I_o=20\n",

-      "R=.5\n",

-      "\n",

-      "#Calculations\n",

-      "V_o1=E+I_o*R\n",

-      "V_s=230\n",

-      "V_ml=math.sqrt(2)*V_s\n",

-      "a1=math.degrees(math.acos(V_o1*math.pi/(3*V_ml)))\n",

-      "th=120\n",

-      "I_s=math.sqrt((1/math.pi)*I_o**2*th*math.pi/180)\n",

-      "P=E*I_o+I_o**2*R\n",

-      "pf=P/(math.sqrt(3)*V_s*I_s)    \n",

-      "V_o2=E-I_o*R\n",

-      "a2=math.degrees(math.acos(-V_o2*math.pi/(3*V_ml))) \n",

-      "\n",

-      "#Results\n",

-      "print(\"firing angle delay=%.3f deg\" %a1)\n",

-      "print(\"pf=%.3f\" %pf)\n",

-      "print(\"firing angle delay=%.2f deg\" %a2)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "firing angle delay=47.461 deg\n",

-        "pf=0.646\n",

-        "firing angle delay=127.71 deg\n"

-       ]

-      }

-     ],

-     "prompt_number": 14

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.18, Page No 332"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=230.0\n",

-      "f=50.0\n",

-      "\n",

-      "#Calculations\n",

-      "w=2*math.pi*f\n",

-      "a1=0\n",

-      "t_c1=(4*math.pi/3-a1*math.pi/180)/w    \n",

-      "a2=30\n",

-      "t_c2=(4*math.pi/3-a2*math.pi/180)/w    \n",

-      "\n",

-      "#Results\n",

-      "print(\"for firing angle delay=0deg\")\n",

-      "print(\"commutation time=%.2f ms\" %(t_c1*1000))\n",

-      "print(\"peak reverse voltage=%.2f V\" %(math.sqrt(2)*V))\n",

-      "print(\"for firing angle delay=30deg\")\n",

-      "print(\"commutation time=%.2f ms\" %(t_c2*1000))\n",

-      "print(\"peak reverse voltage=%.2f V\" %(math.sqrt(2)*V))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for firing angle delay=0deg\n",

-        "commutation time=13.33 ms\n",

-        "peak reverse voltage=325.27 V\n",

-        "for firing angle delay=30deg\n",

-        "commutation time=11.67 ms\n",

-        "peak reverse voltage=325.27 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 15

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.19, Page No 333"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "a=30.0\n",

-      "R=10.0\n",

-      "P=5000.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_s=math.sqrt(P*R*2*math.pi/(2*3)/(math.pi/3+math.sqrt(3)*math.cos(math.radians(2*a))/2))\n",

-      "V_ph=V_s/math.sqrt(3)    \n",

-      "I_or=math.sqrt(P*R)\n",

-      "V_s=I_or*math.pi/(math.sqrt(2)*3*math.cos(math.radians(a)))\n",

-      "V_ph=V_s/math.sqrt(3) \n",

-      "\n",

-      "#Results\n",

-      "print(\"per phase voltage percent V_ph=%.3f V\" %V_ph)   \n",

-      "print(\"for constant load current\")\n",

-      "print(\"V_ph=%.2f V\" %V_ph)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "per phase voltage percent V_ph=110.384 V\n",

-        "for constant load current\n",

-        "V_ph=110.38 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 16

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.20, Page No 334"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "a=30.0\n",

-      "R=10.0\n",

-      "P=5000.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_s=math.sqrt(P*R*4*math.pi/(2*3)/(2*math.pi/3+math.sqrt(3)*(1+math.cos(math.radians(2*a)))/2))\n",

-      "V_ph=V_s/math.sqrt(3)    \n",

-      "I_or=math.sqrt(P*R)\n",

-      "V_s=I_or*2*math.pi/(math.sqrt(2)*3*(1+math.cos(math.radians(a))))\n",

-      "V_ph=V_s/math.sqrt(3)   \n",

-      "\n",

-      "#Results\n",

-      "print(\"per phase voltage percent V_ph=%.3f V\" %V_ph) \n",

-      "print(\"for constant load current\")\n",

-      "print(\"V_ph=%.2f V\" %V_ph)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "per phase voltage percent V_ph=102.459 V\n",

-        "for constant load current\n",

-        "V_ph=102.46 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 17

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.21, Page No 334"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "a=90.0\n",

-      "R=10.0\n",

-      "P=5000.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_s=math.sqrt(P*R*4*math.pi/(2*3)/((math.pi-math.pi/2)+(math.sin(math.radians(2*a)))/2))\n",

-      "V_ph=V_s/math.sqrt(3)    \n",

-      "I_or=math.sqrt(P*R)\n",

-      "V_s=I_or*2*math.pi/(math.sqrt(2)*3*(1+math.cos(math.radians(a))))\n",

-      "V_ph=V_s/math.sqrt(3)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"per phase voltage percent V_ph=%.2f V\" %V_ph)\n",

-      "print(\"for constant load current\")\n",

-      "print(\"V_ph=%.1f V\" %V_ph)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "per phase voltage percent V_ph=191.19 V\n",

-        "for constant load current\n",

-        "V_ph=191.2 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 18

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.22 Page No 334"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "E=200.0\n",

-      "I_o=20.0\n",

-      "R=.5\n",

-      "\n",

-      "#Calculations\n",

-      "V_o=E+I_o*R\n",

-      "V_s=230\n",

-      "V_ml=math.sqrt(2)*V_s\n",

-      "a=math.degrees(math.acos(V_o*2*math.pi/(3*V_ml)-1))  \n",

-      "a1=180-a\n",

-      "I_sr=math.sqrt((1/math.pi)*I_o**2*(a1*math.pi/180))\n",

-      "P=V_o*I_o\n",

-      "pf=P/(math.sqrt(3)*V_s*I_sr)   \n",

-      "\n",

-      "#Results\n",

-      "print(\"firing angle delay=%.2f deg\" %a)\n",

-      "print(\"pf=%.2f\" %pf)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "firing angle delay=69.38 deg\n",

-        "pf=0.67\n"

-       ]

-      }

-     ],

-     "prompt_number": 19

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.23, Page No 335"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=400.0\n",

-      "f=50.0\n",

-      "I_o=15.0\n",

-      "a=45.0\n",

-      "\n",

-      "#Calculations\n",

-      "I_TA=I_o*120.0/360.0\n",

-      "I_Tr=math.sqrt(I_o**2*120/360)\n",

-      "I_sr=math.sqrt(I_o**2*120/180)\n",

-      "V_ml=math.sqrt(2)*V_s\n",

-      "V_o=3*V_ml*math.cos(math.radians(a))/math.pi\n",

-      "V_or=V_ml*math.sqrt((3/(2*math.pi))*(math.pi/3+math.sqrt(3/2)*math.cos(math.radians(2*a))))\n",

-      "I_or=I_o\n",

-      "P_dc=V_o*I_o\n",

-      "P_ac=V_or*I_or\n",

-      "RE=P_dc/P_ac    \n",

-      "VA=3*V_s/math.sqrt(3)*I_sr\n",

-      "TUF=P_dc/VA    \n",

-      "pf=P_ac/VA    \n",

-      "\n",

-      "#Results\n",

-      "print(\"rectification efficiency=%.5f\" %RE)\n",

-      "print(\"TUF=%.4f\" %TUF)\n",

-      "print(\"Input pf=%.3f\" %pf)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rectification efficiency=0.95493\n",

-        "TUF=0.6752\n",

-        "Input pf=0.707\n"

-       ]

-      }

-     ],

-     "prompt_number": 20

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.24, Page No 341"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "I=10.0\n",

-      "a=45.0\n",

-      "V=400.0\n",

-      "f=50.0\n",

-      "\n",

-      "#Calculations\n",

-      "DF=math.cos(math.radians(a))\n",

-      "I_o=10\n",

-      "I_s1=4*I_o/(math.sqrt(2)*math.pi)*math.sin(math.pi/3)\n",

-      "I_sr=I_o*math.sqrt(2.0/3.0)\n",

-      "I_o=1     #suppose\n",

-      "CDF=I_s1/I_sr    \n",

-      "THD=math.sqrt(1/CDF**2-1)    \n",

-      "pf=CDF*DF    \n",

-      "P=(3*math.sqrt(2)*V*math.cos(math.radians(a))/math.pi)*I\n",

-      "Q=(3*math.sqrt(2)*V*math.sin(math.radians(a))/math.pi)*I  \n",

-      "   \n",

-      "#Results\n",

-      "print(\"DF=%.3f\" %DF)\n",

-      "print(\"CDF=%.3f\" %CDF)\n",

-      "print(\"THD=%.5f\" %THD)\n",

-      "print(\"PF=%.4f\" %pf)\n",

-      "print(\"active power=%.2f W\" %P)  \n",

-      "print(\"reactive power=%.2f Var\" %Q)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "DF=0.707\n",

-        "CDF=0.955\n",

-        "THD=0.31084\n",

-        "PF=0.6752\n",

-        "active power=3819.72 W\n",

-        "reactive power=3819.72 Var\n"

-       ]

-      }

-     ],

-     "prompt_number": 21

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.25, Page No 342"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "print(\"for firing angle=30deg\")\n",

-      "a=30.0\n",

-      "V=400.0\n",

-      "V_ml=math.sqrt(2)*V\n",

-      "V_o=3*V_ml*math.cos(math.radians(a))/math.pi\n",

-      "E=350\n",

-      "R=10\n",

-      "\n",

-      "#Calculations\n",

-      "I_o=(V_o-E)/R\n",

-      "I_or=I_o\n",

-      "P1=V_o*I_o    \n",

-      "I_sr=I_o*math.sqrt(2.0/3.0)\n",

-      "VA=3*V/math.sqrt(3)*I_sr\n",

-      "pf=P1/VA \n",

-      "a=180-60\n",

-      "V=400\n",

-      "V_ml=math.sqrt(2)*V\n",

-      "V_o=3*V_ml*math.cos(math.radians(a))/math.pi\n",

-      "E=-350\n",

-      "R=10\n",

-      "I_o=(V_o-E)/R\n",

-      "I_or=I_o\n",

-      "P2=-V_o*I_o    \n",

-      "I_sr=I_o*math.sqrt(2.0/3.0)\n",

-      "VA=3*V/math.sqrt(3)*I_sr\n",

-      "pf=P2/VA       \n",

-      "\n",

-      "print(\"power delivered to load=%.2f W\" %P1)\n",

-      "print(\"pf=%.4f\" %pf)\n",

-      "print(\"for firing advance angle=60deg\")\n",

-      "print(\"power delivered to load=%.2f W\" %P2)\n",

-      "print(\"pf=%.4f\" %pf)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits.\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for firing angle=30deg\n",

-        "power delivered to load=5511.74 W\n",

-        "pf=0.4775\n",

-        "for firing advance angle=60deg\n",

-        "power delivered to load=2158.20 W\n",

-        "pf=0.4775\n"

-       ]

-      }

-     ],

-     "prompt_number": 22

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.26, Page No 347"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "a=0\n",

-      "u=15.0\n",

-      "\n",

-      "#Calculations\n",

-      "i=math.cos(math.radians(a))-math.cos(math.radians(a+u))\n",

-      "a=30\n",

-      "u=math.degrees(math.acos(math.cos(math.radians(a))-i))-a  \n",

-      "a=45\n",

-      "u=math.degrees(math.acos(math.cos(math.radians(a))-i))-a    \n",

-      "a=60\n",

-      "u=math.degrees(math.acos(math.cos(math.radians(a))-i))-a  \n",

-      "\n",

-      "#Results\n",

-      "print(\"for firing angle=30deg\") \n",

-      "print(\"overlap angle=%.1f deg\" %u)\n",

-      "print(\"for firing angle=45deg\")  \n",

-      "print(\"overlap angle=%.1f deg\" %u)\n",

-      "print(\"for firing angle=60deg\") \n",

-      "print(\"overlap angle=%.2f deg\" %u)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for firing angle=30deg\n",

-        "overlap angle=2.2 deg\n",

-        "for firing angle=45deg\n",

-        "overlap angle=2.2 deg\n",

-        "for firing angle=60deg\n",

-        "overlap angle=2.23 deg\n"

-       ]

-      }

-     ],

-     "prompt_number": 23

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.28, Page No 352"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "E=400.0\n",

-      "I_o=20.0\n",

-      "R=1\n",

-      "\n",

-      "#Calculations\n",

-      "V_o=E+I_o*R\n",

-      "f=50.0\n",

-      "w=2*math.pi*f\n",

-      "L=.004\n",

-      "V=230 #per phase voltage\n",

-      "V_ml=math.sqrt(6)*V\n",

-      "a=math.degrees(math.acos(math.pi/(3*V_ml)*(V_o+3*w*L*I_o/math.pi)))   \n",

-      "print(\"firing angle delay=%.3f deg\" %a)\n",

-      "u=math.degrees(math.acos(math.pi/(3*V_ml)*(V_o-3*w*L*I_o/math.pi)))-a    \n",

-      "\n",

-      "#Results\n",

-      "print(\"overlap angle=%.2f deg\" %u)\n",

-      "#Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "firing angle delay=34.382 deg\n",

-        "overlap angle=8.22 deg\n"

-       ]

-      }

-     ],

-     "prompt_number": 24

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.29, Page No 352"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=400.0\n",

-      "f=50.0\n",

-      "w=2*math.pi*f\n",

-      "R=1\n",

-      "E=230\n",

-      "I=15.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_o=-E+I*R\n",

-      "V_ml=math.sqrt(2)*V\n",

-      "a=math.degrees(math.acos(V_o*2*math.pi/(3*V_ml)))  \n",

-      "L=0.004\n",

-      "a=math.degrees(math.acos((2*math.pi)/(3*V_ml)*(V_o+3*w*L*I/(2*math.pi))))  \n",

-      "u=math.degrees(math.acos(math.cos(math.radians(a))-3*f*L*I/V_ml))-a    \n",

-      "\n",

-      "#Results\n",

-      "print(\"firing angle=%.3f deg\" %a)\n",

-      "print(\"firing angle delay=%.3f deg\" %a)\n",

-      "print(\"overlap angle=%.3f deg\" %u)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits.\n",

-      " \n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "firing angle=139.702 deg\n",

-        "firing angle delay=139.702 deg\n",

-        "overlap angle=1.431 deg\n"

-       ]

-      }

-     ],

-     "prompt_number": 25

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.31, Page No 361"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=230.0 #per phase\n",

-      "f=50.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_ml=math.sqrt(3.0)*math.sqrt(2)*V\n",

-      "w=2*math.pi*f\n",

-      "a1=60.0\n",

-      "L=0.015\n",

-      "i_cp=(math.sqrt(3)*V_ml/(w*L))*(1-math.sin(math.radians(a1)))    \n",

-      "\n",

-      "#Results\n",

-      "print(\"circulating current=%.4f A\" %i_cp)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "circulating current=27.7425 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 26

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.32, Page No 362"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=230.0\n",

-      "V_m=math.sqrt(2)*V\n",

-      "a=30.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_o=2*V_m* math.cos(math.radians(a))/math.pi    \n",

-      "R=10\n",

-      "I_o=V_o/R    \n",

-      "I_TA=I_o*math.pi/(2*math.pi)    \n",

-      "I_Tr=math.sqrt(I_o**2*math.pi/(2*math.pi))    \n",

-      "I_s=math.sqrt(I_o**2*math.pi/(math.pi)) \n",

-      "I_o=I_s\n",

-      "pf=(V_o*I_o/(V*I_s))    \n",

-      "\n",

-      "#Results\n",

-      "print(\"avg o/p voltage=%.3f V\" %V_o)\n",

-      "print(\"avg o/p current=%.2f A\" %I_o)\n",

-      "print(\"avg value of thyristor current=%.3f A\" %I_TA)\n",

-      "print(\"rms value of thyristor current=%.2f A\" %I_Tr)\n",

-      "print(\"pf=%.4f\" %pf)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits.\n",

-      " \n",

-      " \n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "avg o/p voltage=179.330 V\n",

-        "avg o/p current=17.93 A\n",

-        "avg value of thyristor current=8.967 A\n",

-        "rms value of thyristor current=12.68 A\n",

-        "pf=0.7797\n"

-       ]

-      }

-     ],

-     "prompt_number": 27

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.33, Page No 363"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=230.0\n",

-      "V_m=math.sqrt(2)*V\n",

-      "a=30.0\n",

-      "L=.0015\n",

-      "\n",

-      "#Calculations\n",

-      "V_o=2*V_m* math.cos(math.radians(a))/math.pi  \n",

-      "R=10\n",

-      "I_o=V_o/R  \n",

-      "f=50\n",

-      "w=2*math.pi*f\n",

-      "V_ox=2*V_m*math.cos(math.radians(a))/math.pi-w*L*I_o/math.pi    \n",

-      "u=math.degrees(math.acos(math.cos(math.radians(a))-I_o*w*L/V_m))-a    \n",

-      "I=I_o\n",

-      "pf=V_o*I_o/(V*I)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"avg o/p voltage=%.3f V\" %V_ox)\n",

-      "print(\"angle of overlap=%.3f deg\" %u)\n",

-      "print(\"pf=%.4f\" %pf)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "avg o/p voltage=176.640 V\n",

-        "angle of overlap=2.855 deg\n",

-        "pf=0.7797\n"

-       ]

-      }

-     ],

-     "prompt_number": 28

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.34, Page No 364"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=415.0\n",

-      "V_ml=math.sqrt(2)*V\n",

-      "a1=35.0 #firing angle advance\n",

-      "\n",

-      "#Calculations\n",

-      "a=180-a1\n",

-      "I_o=80.0\n",

-      "r_s=0.04\n",

-      "v_T=1.5\n",

-      "X_l=.25 #reactance=w*L\n",

-      "E=-3*V_ml*math.cos(math.radians(a))/math.pi+2*I_o*r_s+2*v_T+3*X_l*I_o/math.pi    \n",

-      "\n",

-      "#Results\n",

-      "print(\"mean generator voltage=%.3f V\" %E)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "mean generator voltage=487.590 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 29

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.35, Page No 364"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=415.0\n",

-      "V_ml=math.sqrt(2)*V\n",

-      "R=0.2\n",

-      "I_o=80\n",

-      "r_s=0.04\n",

-      "v_T=1.5\n",

-      "\n",

-      "#Calculations\n",

-      "X_l=.25 #reactance=w*L\n",

-      "a=35\n",

-      "E=-(-3*V_ml*math.cos(math.radians(a))/math.pi+I_o*R+2*I_o*r_s+2*v_T+3*X_l*I_o/math.pi)    \n",

-      "a1=35\n",

-      "a=180-a1\n",

-      "E=(-3*V_ml*math.cos(math.radians(a))/math.pi+I_o*R+2*I_o*r_s+2*v_T+3*X_l*I_o/math.pi) \n",

-      "\n",

-      "#Results\n",

-      "print(\"when firing angle=35deg\")   \n",

-      "print(\"mean generator voltage=%.3f V\" %E)\n",

-      "print(\"when firing angle advance=35deg\")\n",

-      "print(\"mean generator voltage=%.3f V\" %E)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "when firing angle=35deg\n",

-        "mean generator voltage=503.590 V\n",

-        "when firing angle advance=35deg\n",

-        "mean generator voltage=503.590 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 30

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.36, Page No 365"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "R=5.0\n",

-      "V=230.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_mp=math.sqrt(2)*V\n",

-      "a=30.0\n",

-      "E=150.0\n",

-      "B=180-math.degrees(math.asin(E/V_mp))\n",

-      "I_o=(3/(2*math.pi*R))*(V_mp*(math.cos(math.radians(a+30))-math.cos(math.radians(B)))-E*((B-a-30)*math.pi/180))\n",

-      "\n",

-      "#Results\n",

-      "print(\"avg current flowing=%.2f A\" %I_o)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "avg current flowing=19.96 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 31

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.37, Page No 366"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "a=30.0\n",

-      "V=230.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_m=math.sqrt(2)*V\n",

-      "V_o=V_m*(1+math.cos(math.radians(a)))/math.pi    \n",

-      "E=100\n",

-      "R=10\n",

-      "I_o=(V_o-E)/R    \n",

-      "I_TA=I_o*math.pi/(2*math.pi)    \n",

-      "I_Tr=math.sqrt(I_o**2*math.pi/(2*math.pi))    \n",

-      "I_s=math.sqrt(I_o**2*(1-a/180)*math.pi/(math.pi))\n",

-      "I_or=I_o\n",

-      "P=E*I_o+I_or**2*R\n",

-      "pf=(P/(V*I_s))   \n",

-      "f=50\n",

-      "w=2*math.pi*f\n",

-      "t_c=(1-a/180)*math.pi/w    \n",

-      "\n",

-      "#Results\n",

-      "print(\"\\navg o/p current=%.2f A\" %I_o)\n",

-      "print(\"avg o/p voltage=%.3f V\" %V_o)\n",

-      "print(\"avg value of thyristor current=%.2f A\" %I_TA)\n",

-      "print(\"rms value of thyristor current=%.3f A\" %I_Tr)\n",

-      "print(\"avg value of diode current=%.2f A\" %I_TA)\n",

-      "print(\"rms value of diode current=%.3f A\" %I_Tr)\n",

-      "print(\"pf=%.4f\" %pf)\n",

-      "print(\"circuit turn off time=%.2f ms\" %(t_c*1000))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "\n",

-        "avg o/p current=9.32 A\n",

-        "avg o/p voltage=193.202 V\n",

-        "avg value of thyristor current=4.66 A\n",

-        "rms value of thyristor current=6.590 A\n",

-        "avg value of diode current=4.66 A\n",

-        "rms value of diode current=6.590 A\n",

-        "pf=0.9202\n",

-        "circuit turn off time=8.33 ms\n"

-       ]

-      }

-     ],

-     "prompt_number": 32

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.38, Page No 368"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=230.0\n",

-      "V_m=math.sqrt(2)*V\n",

-      "L=0.05\n",

-      "f=50.0\n",

-      "\n",

-      "#Calculations\n",

-      "w=2*math.pi*f\n",

-      "a=30\n",

-      "i_cp=2*V_m*(1-math.cos(math.radians(a)))/(w*L)    \n",

-      "R=30.0\n",

-      "i_l=V_m/R\n",

-      "i1=i_cp+i_l    \n",

-      "i2=i_cp    \n",

-      "\n",

-      "#Results\n",

-      "print(\"peak value of circulating current=%.3f A\" %i_cp)\n",

-      "print(\"peak value of current in convertor 1=%.3f A\" %i1)\n",

-      "print(\"peak value of current in convertor 2=%.3f A\" %i2)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "peak value of circulating current=5.548 A\n",

-        "peak value of current in convertor 1=16.391 A\n",

-        "peak value of current in convertor 2=5.548 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 33

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.39, Page No 370"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "f=50.0\n",

-      "w=2*math.pi*f\n",

-      "R=5.0\n",

-      "L=0.05\n",

-      "\n",

-      "#Calculations\n",

-      "phi=math.degrees(math.atan(w*L/R))  \n",

-      "phi=90+math.degrees(math.atan(w*L/R))   \n",

-      "\n",

-      "#Results\n",

-      "print(\"for no current transients\")\n",

-      "print(\"triggering angle=%.2f deg\" %phi)\n",

-      "print(\"for worst transients\")\n",

-      "print(\"triggering angle=%.2f deg\" %phi)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for no current transients\n",

-        "triggering angle=162.34 deg\n",

-        "for worst transients\n",

-        "triggering angle=162.34 deg\n"

-       ]

-      }

-     ],

-     "prompt_number": 34

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Power_Electronics/Chapter6_4.ipynb b/_Power_Electronics/Chapter6_4.ipynb
deleted file mode 100755
index dff6564b..00000000
--- a/_Power_Electronics/Chapter6_4.ipynb
+++ /dev/null
@@ -1,1761 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 06 : Phase Controlled Rectifiers"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.1, Page No 283"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=230.0\n",

-      "P=1000.0\n",

-      "R=V**2/P\n",

-      "\n",

-      "#Calculations\n",

-      "a=math.pi/4\n",

-      "V_or1=(math.sqrt(2)*V/(2*math.sqrt(math.pi)))*math.sqrt((math.pi-a)+.5*math.sin(2*a))\n",

-      "P1=V_or1**2/R    \n",

-      "a=math.pi/2\n",

-      "V_or2=(math.sqrt(2)*V/(2*math.sqrt(math.pi)))*math.sqrt((math.pi-a)+.5*math.sin(2*a))\n",

-      "P2=V_or2**2/R   \n",

-      "\n",

-      "#Results\n",

-      "print(\"when firing angle delay is of 45deg\")\n",

-      "print(\"power absorbed=%.2f W\" %P1)\n",

-      "print(\"when firing angle delay is of 90deg\")\n",

-      "print(\"power absorbed=%.2f W\" %P2)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "when firing angle delay is of 45deg\n",

-        "power absorbed=454.58 W\n",

-        "when firing angle delay is of 90deg\n",

-        "power absorbed=250.00 W\n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.2, Page No 283"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=230.0\n",

-      "E=150.0\n",

-      "R=8.0\n",

-      "\n",

-      "#Calculations\n",

-      "th1=math.sin(math.radians(E/(math.sqrt(2)*V)))\n",

-      "I_o=(1/(2*math.pi*R))*(2*math.sqrt(2)*230*math.cos(math.radians(th1))-E*(math.pi-2*th1*math.pi/180))    \n",

-      "P=E*I_o    \n",

-      "I_or=math.sqrt((1/(2*math.pi*R**2))*((V**2+E**2)*(math.pi-2*th1*math.pi/180)+V**2*math.sin(math.radians(2*th1))-4*math.sqrt(2)*V*E*math.cos(math.radians(th1))))\n",

-      "P_r=I_or**2*R    \n",

-      "pf=(P+P_r)/(V*I_or)\n",

-      "\n",

-      "#Results\n",

-      "print(\"avg charging curent=%.4f A\" %I_o)\n",

-      "print(\"power supplied to the battery=%.2f W\" %P)\n",

-      "print(\"power dissipated by the resistor=%.3f W\" %P_r)    \n",

-      "print(\"supply pf=%.3f\" %pf)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "avg charging curent=3.5679 A\n",

-        "power supplied to the battery=535.18 W\n",

-        "power dissipated by the resistor=829.760 W\n",

-        "supply pf=0.583\n"

-       ]

-      }

-     ],

-     "prompt_number": 2

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.3 Page No 284"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=230.0\n",

-      "E=150.0\n",

-      "R=8.0\n",

-      "a=35.0\n",

-      "\n",

-      "#Calculations\n",

-      "th1=math.degrees(math.asin(E/(math.sqrt(2)*V)))\n",

-      "th2=180-th1\n",

-      "I_o=(1/(2*math.pi*R))*(math.sqrt(2)*230*(math.cos(math.radians(a))-math.cos(math.radians(th2)))-E*((th2-a)*math.pi/180))    \n",

-      "P=E*I_o    \n",

-      "I_or=math.sqrt((1/(2*math.pi*R**2))*((V**2+E**2)*((th2-a)*math.pi/180)-(V**2/2)*(math.sin(math.radians(2*th2))-math.sin(math.radians(2*a)))-2*math.sqrt(2)*V*E*(math.cos(math.radians(a))-math.cos(math.radians(th2)))))\n",

-      "P_r=I_or**2*R    \n",

-      "pf=(P+P_r)/(V*I_or)    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"avg charging curent=%.4f A\" %I_o)\n",

-      "print(\"power supplied to the battery=%.2f W\" %P)\n",

-      "print(\"power dissipated by the resistor=%.2f W\" %P_r)\n",

-      "print(\"supply pf=%.4f\" %pf)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "avg charging curent=4.9208 A\n",

-        "power supplied to the battery=738.12 W\n",

-        "power dissipated by the resistor=689.54 W\n",

-        "supply pf=0.6686\n"

-       ]

-      }

-     ],

-     "prompt_number": 3

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.4, Page No 285"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "B=210\n",

-      "f=50.0     #Hz\n",

-      "w=2*math.pi*f\n",

-      "a=40.0     #firing angle\n",

-      "V=230.0\n",

-      "R=5.0\n",

-      "L=2*10**-3\n",

-      "\n",

-      "#Calculations\n",

-      "t_c1=(360-B)*math.pi/(180*w)   \n",

-      "V_o1=(math.sqrt(2)*230/(2*math.pi))*(math.cos(math.radians(a))-math.cos(math.radians(B)))    \n",

-      "I_o1=V_o1/R    \n",

-      "E=110\n",

-      "R=5\n",

-      "L=2*10**-3\n",

-      "th1=math.degrees(math.asin(E/(math.sqrt(2)*V)))\n",

-      "t_c2=(360-B+th1)*math.pi/(180*w)    \n",

-      "V_o2=(math.sqrt(2)*230/(2*math.pi))*(math.cos(math.radians(a))-math.cos(math.radians(B)))    \n",

-      "I_o2=(1/(2*math.pi*R))*(math.sqrt(2)*230*(math.cos(math.radians(a))-math.cos(math.radians(B)))-E*((B-a)*math.pi/180))   \n",

-      "V_o2=R*I_o2+E    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"for R=5ohm and L=2mH\")\n",

-      "print(\"ckt turn off time=%.3f msec\" %(t_c1*1000))\n",

-      "print(\"avg output voltage=%.3f V\" %V_o1)\n",

-      "print(\"avg output current=%.4f A\" %I_o1)\n",

-      "print(\"for R=5ohm % L=2mH and E=110V\")\n",

-      "print(\"ckt turn off time=%.3f msec\" %(t_c2*1000))\n",

-      "print(\"avg output current=%.4f A\" %I_o2)\n",

-      "print(\"avg output voltage=%.3f V\" %V_o2)   "

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for R=5ohm and L=2mH\n",

-        "ckt turn off time=8.333 msec\n",

-        "avg output voltage=84.489 V\n",

-        "avg output current=16.8979 A\n",

-        "for R=5ohm % L=2mH and E=110V\n",

-        "ckt turn off time=9.431 msec\n",

-        "avg output current=6.5090 A\n",

-        "avg output voltage=142.545 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 4

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.5 Page No 286"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "f=50.0\n",

-      "R=10.0\n",

-      "a=60.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_m=(math.sqrt(2)*V_s)\n",

-      "V_o=V_m/(2*math.pi)*(1+math.cos(math.radians(a)))\n",

-      "I_o=V_o/R\n",

-      "V_or=(V_m/(2*math.sqrt(math.pi)))*math.sqrt((math.pi-a*math.pi/180)+.5*math.sin(math.radians(2*a)))\n",

-      "I_or=V_or/R\n",

-      "P_dc=V_o*I_o\n",

-      "P_ac=V_or*I_or\n",

-      "RE=P_dc/P_ac    \n",

-      "FF=V_or/V_o    \n",

-      "VRF=math.sqrt(FF**2-1)    \n",

-      "TUF=P_dc/(V_s*I_or)    \n",

-      "PIV=V_m    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"rectification efficiency=%.4f\" %RE)\n",

-      "print(\"form factor=%.3f\" %FF)\n",

-      "print(\"voltage ripple factor=%.4f\" %VRF)\n",

-      "print(\"t/f utilisation factor=%.4f\" %TUF)\n",

-      "print(\"PIV of thyristor=%.2f V\" %PIV)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rectification efficiency=0.2834\n",

-        "form factor=1.879\n",

-        "voltage ripple factor=1.5903\n",

-        "t/f utilisation factor=0.1797\n",

-        "PIV of thyristor=325.27 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 5

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.6 Page No 294"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=1000.0\n",

-      "fos=2.5     #factor of safety\n",

-      "I_TAV=40.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_m1=V/(2*fos)\n",

-      "P1=(2*V_m1/math.pi)*I_TAV    \n",

-      "V_m2=V/(fos)\n",

-      "P2=(2*V_m2/math.pi)*I_TAV    \n",

-      "\n",

-      "#Results\n",

-      "print(\"for mid pt convertor\")\n",

-      "print(\"power handled=%.3f kW\" %(P1/1000))\n",

-      "print(\"for bridge convertor\")\n",

-      "print(\"power handled=%.3f kW\" %(P2/1000))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for mid pt convertor\n",

-        "power handled=5.093 kW\n",

-        "for bridge convertor\n",

-        "power handled=10.186 kW\n"

-       ]

-      }

-     ],

-     "prompt_number": 6

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.7, Page No 297"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "R=.4\n",

-      "I_o=10\n",

-      "I_or=I_o\n",

-      "E=120.0\n",

-      "\n",

-      "#Calculations\n",

-      "a1=math.degrees(math.acos((E+I_o*R)*math.pi/(2*V_m)))\n",

-      "pf1=(E*I_o+I_or**2*R)/(V_s*I_or)    \n",

-      "E=-120.0\n",

-      "a2=math.degrees(math.acos((E+I_o*R)*math.pi/(2*V_m))) \n",

-      "pf2=(-E*I_o-I_or**2*R)/(V_s*I_or)   \n",

-      "\n",

-      "#Results\n",

-      "print(\"firing angle delay=%.2f deg\" %a1)\n",

-      "print(\"pf=%.4f\" %pf1)\n",

-      "print(\"firing angle delay=%.2f deg\" %a2)\n",

-      "print(\"pf=%.4f\" %pf2)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "firing angle delay=53.21 deg\n",

-        "pf=0.5391\n",

-        "firing angle delay=124.07 deg\n",

-        "pf=0.5043\n"

-       ]

-      }

-     ],

-     "prompt_number": 7

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.9 Page No 299"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "f=50.0\n",

-      "a=45.0\n",

-      "R=5.0\n",

-      "E=100.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_o=((math.sqrt(2)*V_s)/(2*math.pi))*(3+math.cos(math.radians(a)))\n",

-      "I_o=(V_o-E)/R    \n",

-      "P=E*I_o    \n",

-      "\n",

-      "#Results\n",

-      "print(\"avg o/p current=%.3f A\" %I_o)\n",

-      "print(\"power delivered to battery=%.4f kW\" %(P/1000))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "avg o/p current=18.382 A\n",

-        "power delivered to battery=1.8382 kW\n"

-       ]

-      }

-     ],

-     "prompt_number": 8

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.10 Page No 300"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variablesV_s=230\n",

-      "f=50.0\n",

-      "a=50.0\n",

-      "R=6.0\n",

-      "E=60.0\n",

-      "V_o1=((math.sqrt(2)*2*V_s)/(math.pi))*math.cos(math.radians(a))\n",

-      "I_o1=(V_o1-E)/R    \n",

-      "\n",

-      "#ATQ after applying the conditions\n",

-      "V_o2=((math.sqrt(2)*V_s)/(math.pi))*math.cos(math.radians(a))\n",

-      "I_o2=(V_o2-E)/R    \n",

-      "\n",

-      "print(\"avg o/p current=%.3f A\" %I_o1)\n",

-      "print(\"avg o/p current after change=%.2f A\" %I_o2)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "avg o/p current=12.184 A\n",

-        "avg o/p current after change=1.09 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 9

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.11 Page No 309"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "a=45.0\n",

-      "R=10.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_o=(2*V_m/math.pi)*math.cos(math.radians(a))\n",

-      "I_o=V_o/R\n",

-      "V_or=V_m/math.sqrt(2)\n",

-      "I_or=I_o\n",

-      "P_dc=V_o*I_o\n",

-      "P_ac=V_or*I_or\n",

-      "RE=P_dc/P_ac    \n",

-      "FF=V_or/V_o    \n",

-      "VRF=math.sqrt(FF**2-1)    \n",

-      "I_s1=2*math.sqrt(2)*I_o/math.pi\n",

-      "DF=math.cos(math.radians(a))\n",

-      "CDF=.90032\n",

-      "pf=CDF*DF    \n",

-      "HF=math.sqrt((1/CDF**2)-1)    \n",

-      "Q=2*V_m*I_o*math.sin(math.radians(a))/math.pi \n",

-      "\n",

-      "#Results\n",

-      "print(\"rectification efficiency=%.4f\" %RE)\n",

-      "print(\"form factor=%.4f\" %FF)\n",

-      "print(\"voltage ripple factor=%.4f\" %VRF)\n",

-      "print(\"pf=%.5f\" %pf)\n",

-      "print(\"HF=%.5f\" %HF)\n",

-      "print(\"active power=%.2f W\" %P_dc)   \n",

-      "print(\"reactive power=%.3f Var\" %Q)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rectification efficiency=0.6366\n",

-        "form factor=1.5708\n",

-        "voltage ripple factor=1.2114\n",

-        "pf=0.63662\n",

-        "HF=0.48342\n",

-        "active power=2143.96 W\n",

-        "reactive power=2143.956 Var\n"

-       ]

-      }

-     ],

-     "prompt_number": 10

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.12, Page No 310"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "a=45.0\n",

-      "R=10.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_o=(V_m/math.pi)*(1+math.cos(math.radians(a)))\n",

-      "I_o=V_o/R\n",

-      "V_or=V_s*math.sqrt((1/math.pi)*((math.pi-a*math.pi/180)+math.sin(math.radians(2*a))/2))\n",

-      "I_or=I_o\n",

-      "P_dc=V_o*I_o\n",

-      "P_ac=V_or*I_or\n",

-      "RE=P_dc/P_ac    \n",

-      "FF=V_or/V_o    \n",

-      "VRF=math.sqrt(FF**2-1)    \n",

-      "I_s1=2*math.sqrt(2)*I_o*math.cos(math.radians(a/2))/math.pi\n",

-      "DF=math.cos(math.radians(a/2))   \n",

-      "CDF=2*math.sqrt(2)*math.cos(math.radians(a/2))/math.sqrt(math.pi*(math.pi-a*math.pi/180))    \n",

-      "pf=CDF*DF    \n",

-      "HF=math.sqrt((1/CDF**2)-1)    \n",

-      "Q=V_m*I_o*math.sin(math.radians(a))/math.pi\n",

-      "\n",

-      "#Results\n",

-      "print(\"form factor=%.3f\" %FF)\n",

-      "print(\"rectification efficiency=%.4f\" %RE)\n",

-      "print(\"voltage ripple factor=%.3f\" %VRF)    \n",

-      "print(\"DF=%.4f\" %DF)\n",

-      "print(\"CDF=%.4f\" %CDF)\n",

-      "print(\"pf=%.4f\" %pf)\n",

-      "print(\"HF=%.4f\" %HF)\n",

-      "print(\"active power=%.3f W\" %P_dc)\n",

-      "print(\"reactive power=%.2f Var\" %Q)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "form factor=1.241\n",

-        "rectification efficiency=0.8059\n",

-        "voltage ripple factor=0.735\n",

-        "DF=0.9239\n",

-        "CDF=0.9605\n",

-        "pf=0.8874\n",

-        "HF=0.2899\n",

-        "active power=3123.973 W\n",

-        "reactive power=1293.99 Var\n"

-       ]

-      }

-     ],

-     "prompt_number": 11

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.13, Page No 319"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "R=10.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_ml=math.sqrt(2)*V_s\n",

-      "V_om=3*V_ml/(2*math.pi)\n",

-      "V_o=V_om/2\n",

-      "th=30\n",

-      "a=math.degrees(math.acos((2*math.pi*math.sqrt(3)*V_o/(3*V_ml)-1)))-th    \n",

-      "I_o=V_o/R    \n",

-      "V_or=V_ml/(2*math.sqrt(math.pi))*math.sqrt((5*math.pi/6-a*math.pi/180)+.5*math.sin(math.radians(2*a+2*th)))\n",

-      "I_or=V_or/R    \n",

-      "RE=V_o*I_o/(V_or*I_or)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"delay angle=%.1f deg\" %a)\n",

-      "print(\"avg load current=%.3f A\" %I_o)\n",

-      "print(\"rms load current=%.3f A\" %I_or)\n",

-      "print(\"rectification efficiency=%.4f\" %RE)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "delay angle=67.7 deg\n",

-        "avg load current=7.765 A\n",

-        "rms load current=10.477 A\n",

-        "rectification efficiency=0.5494\n"

-       ]

-      }

-     ],

-     "prompt_number": 12

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.15, Page No 321"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=400.0\n",

-      "V_ml=math.sqrt(2)*V\n",

-      "v_T=1.4\n",

-      "a1=30.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_o1=3*V_ml/(2*math.pi)*math.cos(math.radians(a1))-v_T   \n",

-      "a2=60.0\n",

-      "V_o2=3*V_ml/(2*math.pi)*math.cos(math.radians(a2))-v_T  \n",

-      "I_o=36\n",

-      "I_TA=I_o/3    \n",

-      "I_Tr=I_o/math.sqrt(3)    \n",

-      "P=I_TA*v_T       \n",

-      "\n",

-      "#Results\n",

-      "print(\"for firing angle = 30deg\")\n",

-      "print(\"avg output voltage=%.3f V\" %V_o1)\n",

-      "print(\"for firing angle = 60deg\")\n",

-      "print(\"avg output voltage=%.2f V\" %V_o2)\n",

-      "print(\"avg current rating=%.0f A\" %I_TA)\n",

-      "print(\"rms current rating=%.3f A\" %I_Tr)\n",

-      "print(\"PIV of SCR=%.1f V\" %V_ml)\n",

-      "print(\"power dissipated=%.1f W\" %P)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for firing angle = 30deg\n",

-        "avg output voltage=232.509 V\n",

-        "for firing angle = 60deg\n",

-        "avg output voltage=133.65 V\n",

-        "avg current rating=12 A\n",

-        "rms current rating=20.785 A\n",

-        "PIV of SCR=565.7 V\n",

-        "power dissipated=16.8 W\n"

-       ]

-      }

-     ],

-     "prompt_number": 13

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.17, Page No 331"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "E=200\n",

-      "I_o=20\n",

-      "R=.5\n",

-      "\n",

-      "#Calculations\n",

-      "V_o1=E+I_o*R\n",

-      "V_s=230\n",

-      "V_ml=math.sqrt(2)*V_s\n",

-      "a1=math.degrees(math.acos(V_o1*math.pi/(3*V_ml)))\n",

-      "th=120\n",

-      "I_s=math.sqrt((1/math.pi)*I_o**2*th*math.pi/180)\n",

-      "P=E*I_o+I_o**2*R\n",

-      "pf=P/(math.sqrt(3)*V_s*I_s)    \n",

-      "V_o2=E-I_o*R\n",

-      "a2=math.degrees(math.acos(-V_o2*math.pi/(3*V_ml))) \n",

-      "\n",

-      "#Results\n",

-      "print(\"firing angle delay=%.3f deg\" %a1)\n",

-      "print(\"pf=%.3f\" %pf)\n",

-      "print(\"firing angle delay=%.2f deg\" %a2)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "firing angle delay=47.461 deg\n",

-        "pf=0.646\n",

-        "firing angle delay=127.71 deg\n"

-       ]

-      }

-     ],

-     "prompt_number": 14

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.18, Page No 332"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=230.0\n",

-      "f=50.0\n",

-      "\n",

-      "#Calculations\n",

-      "w=2*math.pi*f\n",

-      "a1=0\n",

-      "t_c1=(4*math.pi/3-a1*math.pi/180)/w    \n",

-      "a2=30\n",

-      "t_c2=(4*math.pi/3-a2*math.pi/180)/w    \n",

-      "\n",

-      "#Results\n",

-      "print(\"for firing angle delay=0deg\")\n",

-      "print(\"commutation time=%.2f ms\" %(t_c1*1000))\n",

-      "print(\"peak reverse voltage=%.2f V\" %(math.sqrt(2)*V))\n",

-      "print(\"for firing angle delay=30deg\")\n",

-      "print(\"commutation time=%.2f ms\" %(t_c2*1000))\n",

-      "print(\"peak reverse voltage=%.2f V\" %(math.sqrt(2)*V))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for firing angle delay=0deg\n",

-        "commutation time=13.33 ms\n",

-        "peak reverse voltage=325.27 V\n",

-        "for firing angle delay=30deg\n",

-        "commutation time=11.67 ms\n",

-        "peak reverse voltage=325.27 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 15

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.19, Page No 333"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "a=30.0\n",

-      "R=10.0\n",

-      "P=5000.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_s=math.sqrt(P*R*2*math.pi/(2*3)/(math.pi/3+math.sqrt(3)*math.cos(math.radians(2*a))/2))\n",

-      "V_ph=V_s/math.sqrt(3)    \n",

-      "I_or=math.sqrt(P*R)\n",

-      "V_s=I_or*math.pi/(math.sqrt(2)*3*math.cos(math.radians(a)))\n",

-      "V_ph=V_s/math.sqrt(3) \n",

-      "\n",

-      "#Results\n",

-      "print(\"per phase voltage percent V_ph=%.3f V\" %V_ph)   \n",

-      "print(\"for constant load current\")\n",

-      "print(\"V_ph=%.2f V\" %V_ph)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "per phase voltage percent V_ph=110.384 V\n",

-        "for constant load current\n",

-        "V_ph=110.38 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 16

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.20, Page No 334"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "a=30.0\n",

-      "R=10.0\n",

-      "P=5000.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_s=math.sqrt(P*R*4*math.pi/(2*3)/(2*math.pi/3+math.sqrt(3)*(1+math.cos(math.radians(2*a)))/2))\n",

-      "V_ph=V_s/math.sqrt(3)    \n",

-      "I_or=math.sqrt(P*R)\n",

-      "V_s=I_or*2*math.pi/(math.sqrt(2)*3*(1+math.cos(math.radians(a))))\n",

-      "V_ph=V_s/math.sqrt(3)   \n",

-      "\n",

-      "#Results\n",

-      "print(\"per phase voltage percent V_ph=%.3f V\" %V_ph) \n",

-      "print(\"for constant load current\")\n",

-      "print(\"V_ph=%.2f V\" %V_ph)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "per phase voltage percent V_ph=102.459 V\n",

-        "for constant load current\n",

-        "V_ph=102.46 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 17

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.21, Page No 334"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "a=90.0\n",

-      "R=10.0\n",

-      "P=5000.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_s=math.sqrt(P*R*4*math.pi/(2*3)/((math.pi-math.pi/2)+(math.sin(math.radians(2*a)))/2))\n",

-      "V_ph=V_s/math.sqrt(3)    \n",

-      "I_or=math.sqrt(P*R)\n",

-      "V_s=I_or*2*math.pi/(math.sqrt(2)*3*(1+math.cos(math.radians(a))))\n",

-      "V_ph=V_s/math.sqrt(3)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"per phase voltage percent V_ph=%.2f V\" %V_ph)\n",

-      "print(\"for constant load current\")\n",

-      "print(\"V_ph=%.1f V\" %V_ph)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "per phase voltage percent V_ph=191.19 V\n",

-        "for constant load current\n",

-        "V_ph=191.2 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 18

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.22 Page No 334"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "E=200.0\n",

-      "I_o=20.0\n",

-      "R=.5\n",

-      "\n",

-      "#Calculations\n",

-      "V_o=E+I_o*R\n",

-      "V_s=230\n",

-      "V_ml=math.sqrt(2)*V_s\n",

-      "a=math.degrees(math.acos(V_o*2*math.pi/(3*V_ml)-1))  \n",

-      "a1=180-a\n",

-      "I_sr=math.sqrt((1/math.pi)*I_o**2*(a1*math.pi/180))\n",

-      "P=V_o*I_o\n",

-      "pf=P/(math.sqrt(3)*V_s*I_sr)   \n",

-      "\n",

-      "#Results\n",

-      "print(\"firing angle delay=%.2f deg\" %a)\n",

-      "print(\"pf=%.2f\" %pf)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "firing angle delay=69.38 deg\n",

-        "pf=0.67\n"

-       ]

-      }

-     ],

-     "prompt_number": 19

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.23, Page No 335"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=400.0\n",

-      "f=50.0\n",

-      "I_o=15.0\n",

-      "a=45.0\n",

-      "\n",

-      "#Calculations\n",

-      "I_TA=I_o*120.0/360.0\n",

-      "I_Tr=math.sqrt(I_o**2*120/360)\n",

-      "I_sr=math.sqrt(I_o**2*120/180)\n",

-      "V_ml=math.sqrt(2)*V_s\n",

-      "V_o=3*V_ml*math.cos(math.radians(a))/math.pi\n",

-      "V_or=V_ml*math.sqrt((3/(2*math.pi))*(math.pi/3+math.sqrt(3/2)*math.cos(math.radians(2*a))))\n",

-      "I_or=I_o\n",

-      "P_dc=V_o*I_o\n",

-      "P_ac=V_or*I_or\n",

-      "RE=P_dc/P_ac    \n",

-      "VA=3*V_s/math.sqrt(3)*I_sr\n",

-      "TUF=P_dc/VA    \n",

-      "pf=P_ac/VA    \n",

-      "\n",

-      "#Results\n",

-      "print(\"rectification efficiency=%.5f\" %RE)\n",

-      "print(\"TUF=%.4f\" %TUF)\n",

-      "print(\"Input pf=%.3f\" %pf)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rectification efficiency=0.95493\n",

-        "TUF=0.6752\n",

-        "Input pf=0.707\n"

-       ]

-      }

-     ],

-     "prompt_number": 20

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.24, Page No 341"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "I=10.0\n",

-      "a=45.0\n",

-      "V=400.0\n",

-      "f=50.0\n",

-      "\n",

-      "#Calculations\n",

-      "DF=math.cos(math.radians(a))\n",

-      "I_o=10\n",

-      "I_s1=4*I_o/(math.sqrt(2)*math.pi)*math.sin(math.pi/3)\n",

-      "I_sr=I_o*math.sqrt(2.0/3.0)\n",

-      "I_o=1     #suppose\n",

-      "CDF=I_s1/I_sr    \n",

-      "THD=math.sqrt(1/CDF**2-1)    \n",

-      "pf=CDF*DF    \n",

-      "P=(3*math.sqrt(2)*V*math.cos(math.radians(a))/math.pi)*I\n",

-      "Q=(3*math.sqrt(2)*V*math.sin(math.radians(a))/math.pi)*I  \n",

-      "   \n",

-      "#Results\n",

-      "print(\"DF=%.3f\" %DF)\n",

-      "print(\"CDF=%.3f\" %CDF)\n",

-      "print(\"THD=%.5f\" %THD)\n",

-      "print(\"PF=%.4f\" %pf)\n",

-      "print(\"active power=%.2f W\" %P)  \n",

-      "print(\"reactive power=%.2f Var\" %Q)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "DF=0.707\n",

-        "CDF=0.955\n",

-        "THD=0.31084\n",

-        "PF=0.6752\n",

-        "active power=3819.72 W\n",

-        "reactive power=3819.72 Var\n"

-       ]

-      }

-     ],

-     "prompt_number": 21

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.25, Page No 342"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "print(\"for firing angle=30deg\")\n",

-      "a=30.0\n",

-      "V=400.0\n",

-      "V_ml=math.sqrt(2)*V\n",

-      "V_o=3*V_ml*math.cos(math.radians(a))/math.pi\n",

-      "E=350\n",

-      "R=10\n",

-      "\n",

-      "#Calculations\n",

-      "I_o=(V_o-E)/R\n",

-      "I_or=I_o\n",

-      "P1=V_o*I_o    \n",

-      "I_sr=I_o*math.sqrt(2.0/3.0)\n",

-      "VA=3*V/math.sqrt(3)*I_sr\n",

-      "pf=P1/VA \n",

-      "a=180-60\n",

-      "V=400\n",

-      "V_ml=math.sqrt(2)*V\n",

-      "V_o=3*V_ml*math.cos(math.radians(a))/math.pi\n",

-      "E=-350\n",

-      "R=10\n",

-      "I_o=(V_o-E)/R\n",

-      "I_or=I_o\n",

-      "P2=-V_o*I_o    \n",

-      "I_sr=I_o*math.sqrt(2.0/3.0)\n",

-      "VA=3*V/math.sqrt(3)*I_sr\n",

-      "pf=P2/VA       \n",

-      "\n",

-      "print(\"power delivered to load=%.2f W\" %P1)\n",

-      "print(\"pf=%.4f\" %pf)\n",

-      "print(\"for firing advance angle=60deg\")\n",

-      "print(\"power delivered to load=%.2f W\" %P2)\n",

-      "print(\"pf=%.4f\" %pf)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits.\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for firing angle=30deg\n",

-        "power delivered to load=5511.74 W\n",

-        "pf=0.4775\n",

-        "for firing advance angle=60deg\n",

-        "power delivered to load=2158.20 W\n",

-        "pf=0.4775\n"

-       ]

-      }

-     ],

-     "prompt_number": 22

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.26, Page No 347"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "a=0\n",

-      "u=15.0\n",

-      "\n",

-      "#Calculations\n",

-      "i=math.cos(math.radians(a))-math.cos(math.radians(a+u))\n",

-      "a=30\n",

-      "u=math.degrees(math.acos(math.cos(math.radians(a))-i))-a  \n",

-      "a=45\n",

-      "u=math.degrees(math.acos(math.cos(math.radians(a))-i))-a    \n",

-      "a=60\n",

-      "u=math.degrees(math.acos(math.cos(math.radians(a))-i))-a  \n",

-      "\n",

-      "#Results\n",

-      "print(\"for firing angle=30deg\") \n",

-      "print(\"overlap angle=%.1f deg\" %u)\n",

-      "print(\"for firing angle=45deg\")  \n",

-      "print(\"overlap angle=%.1f deg\" %u)\n",

-      "print(\"for firing angle=60deg\") \n",

-      "print(\"overlap angle=%.2f deg\" %u)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for firing angle=30deg\n",

-        "overlap angle=2.2 deg\n",

-        "for firing angle=45deg\n",

-        "overlap angle=2.2 deg\n",

-        "for firing angle=60deg\n",

-        "overlap angle=2.23 deg\n"

-       ]

-      }

-     ],

-     "prompt_number": 23

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.28, Page No 352"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "E=400.0\n",

-      "I_o=20.0\n",

-      "R=1\n",

-      "\n",

-      "#Calculations\n",

-      "V_o=E+I_o*R\n",

-      "f=50.0\n",

-      "w=2*math.pi*f\n",

-      "L=.004\n",

-      "V=230 #per phase voltage\n",

-      "V_ml=math.sqrt(6)*V\n",

-      "a=math.degrees(math.acos(math.pi/(3*V_ml)*(V_o+3*w*L*I_o/math.pi)))   \n",

-      "print(\"firing angle delay=%.3f deg\" %a)\n",

-      "u=math.degrees(math.acos(math.pi/(3*V_ml)*(V_o-3*w*L*I_o/math.pi)))-a    \n",

-      "\n",

-      "#Results\n",

-      "print(\"overlap angle=%.2f deg\" %u)\n",

-      "#Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "firing angle delay=34.382 deg\n",

-        "overlap angle=8.22 deg\n"

-       ]

-      }

-     ],

-     "prompt_number": 24

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.29, Page No 352"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=400.0\n",

-      "f=50.0\n",

-      "w=2*math.pi*f\n",

-      "R=1\n",

-      "E=230\n",

-      "I=15.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_o=-E+I*R\n",

-      "V_ml=math.sqrt(2)*V\n",

-      "a=math.degrees(math.acos(V_o*2*math.pi/(3*V_ml)))  \n",

-      "L=0.004\n",

-      "a=math.degrees(math.acos((2*math.pi)/(3*V_ml)*(V_o+3*w*L*I/(2*math.pi))))  \n",

-      "u=math.degrees(math.acos(math.cos(math.radians(a))-3*f*L*I/V_ml))-a    \n",

-      "\n",

-      "#Results\n",

-      "print(\"firing angle=%.3f deg\" %a)\n",

-      "print(\"firing angle delay=%.3f deg\" %a)\n",

-      "print(\"overlap angle=%.3f deg\" %u)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits.\n",

-      " \n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "firing angle=139.702 deg\n",

-        "firing angle delay=139.702 deg\n",

-        "overlap angle=1.431 deg\n"

-       ]

-      }

-     ],

-     "prompt_number": 25

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.31, Page No 361"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=230.0 #per phase\n",

-      "f=50.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_ml=math.sqrt(3.0)*math.sqrt(2)*V\n",

-      "w=2*math.pi*f\n",

-      "a1=60.0\n",

-      "L=0.015\n",

-      "i_cp=(math.sqrt(3)*V_ml/(w*L))*(1-math.sin(math.radians(a1)))    \n",

-      "\n",

-      "#Results\n",

-      "print(\"circulating current=%.4f A\" %i_cp)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "circulating current=27.7425 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 26

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.32, Page No 362"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=230.0\n",

-      "V_m=math.sqrt(2)*V\n",

-      "a=30.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_o=2*V_m* math.cos(math.radians(a))/math.pi    \n",

-      "R=10\n",

-      "I_o=V_o/R    \n",

-      "I_TA=I_o*math.pi/(2*math.pi)    \n",

-      "I_Tr=math.sqrt(I_o**2*math.pi/(2*math.pi))    \n",

-      "I_s=math.sqrt(I_o**2*math.pi/(math.pi)) \n",

-      "I_o=I_s\n",

-      "pf=(V_o*I_o/(V*I_s))    \n",

-      "\n",

-      "#Results\n",

-      "print(\"avg o/p voltage=%.3f V\" %V_o)\n",

-      "print(\"avg o/p current=%.2f A\" %I_o)\n",

-      "print(\"avg value of thyristor current=%.3f A\" %I_TA)\n",

-      "print(\"rms value of thyristor current=%.2f A\" %I_Tr)\n",

-      "print(\"pf=%.4f\" %pf)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits.\n",

-      " \n",

-      " \n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "avg o/p voltage=179.330 V\n",

-        "avg o/p current=17.93 A\n",

-        "avg value of thyristor current=8.967 A\n",

-        "rms value of thyristor current=12.68 A\n",

-        "pf=0.7797\n"

-       ]

-      }

-     ],

-     "prompt_number": 27

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.33, Page No 363"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=230.0\n",

-      "V_m=math.sqrt(2)*V\n",

-      "a=30.0\n",

-      "L=.0015\n",

-      "\n",

-      "#Calculations\n",

-      "V_o=2*V_m* math.cos(math.radians(a))/math.pi  \n",

-      "R=10\n",

-      "I_o=V_o/R  \n",

-      "f=50\n",

-      "w=2*math.pi*f\n",

-      "V_ox=2*V_m*math.cos(math.radians(a))/math.pi-w*L*I_o/math.pi    \n",

-      "u=math.degrees(math.acos(math.cos(math.radians(a))-I_o*w*L/V_m))-a    \n",

-      "I=I_o\n",

-      "pf=V_o*I_o/(V*I)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"avg o/p voltage=%.3f V\" %V_ox)\n",

-      "print(\"angle of overlap=%.3f deg\" %u)\n",

-      "print(\"pf=%.4f\" %pf)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "avg o/p voltage=176.640 V\n",

-        "angle of overlap=2.855 deg\n",

-        "pf=0.7797\n"

-       ]

-      }

-     ],

-     "prompt_number": 28

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.34, Page No 364"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=415.0\n",

-      "V_ml=math.sqrt(2)*V\n",

-      "a1=35.0 #firing angle advance\n",

-      "\n",

-      "#Calculations\n",

-      "a=180-a1\n",

-      "I_o=80.0\n",

-      "r_s=0.04\n",

-      "v_T=1.5\n",

-      "X_l=.25 #reactance=w*L\n",

-      "E=-3*V_ml*math.cos(math.radians(a))/math.pi+2*I_o*r_s+2*v_T+3*X_l*I_o/math.pi    \n",

-      "\n",

-      "#Results\n",

-      "print(\"mean generator voltage=%.3f V\" %E)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "mean generator voltage=487.590 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 29

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.35, Page No 364"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=415.0\n",

-      "V_ml=math.sqrt(2)*V\n",

-      "R=0.2\n",

-      "I_o=80\n",

-      "r_s=0.04\n",

-      "v_T=1.5\n",

-      "\n",

-      "#Calculations\n",

-      "X_l=.25 #reactance=w*L\n",

-      "a=35\n",

-      "E=-(-3*V_ml*math.cos(math.radians(a))/math.pi+I_o*R+2*I_o*r_s+2*v_T+3*X_l*I_o/math.pi)    \n",

-      "a1=35\n",

-      "a=180-a1\n",

-      "E=(-3*V_ml*math.cos(math.radians(a))/math.pi+I_o*R+2*I_o*r_s+2*v_T+3*X_l*I_o/math.pi) \n",

-      "\n",

-      "#Results\n",

-      "print(\"when firing angle=35deg\")   \n",

-      "print(\"mean generator voltage=%.3f V\" %E)\n",

-      "print(\"when firing angle advance=35deg\")\n",

-      "print(\"mean generator voltage=%.3f V\" %E)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "when firing angle=35deg\n",

-        "mean generator voltage=503.590 V\n",

-        "when firing angle advance=35deg\n",

-        "mean generator voltage=503.590 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 30

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.36, Page No 365"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "R=5.0\n",

-      "V=230.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_mp=math.sqrt(2)*V\n",

-      "a=30.0\n",

-      "E=150.0\n",

-      "B=180-math.degrees(math.asin(E/V_mp))\n",

-      "I_o=(3/(2*math.pi*R))*(V_mp*(math.cos(math.radians(a+30))-math.cos(math.radians(B)))-E*((B-a-30)*math.pi/180))\n",

-      "\n",

-      "#Results\n",

-      "print(\"avg current flowing=%.2f A\" %I_o)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "avg current flowing=19.96 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 31

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.37, Page No 366"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "a=30.0\n",

-      "V=230.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_m=math.sqrt(2)*V\n",

-      "V_o=V_m*(1+math.cos(math.radians(a)))/math.pi    \n",

-      "E=100\n",

-      "R=10\n",

-      "I_o=(V_o-E)/R    \n",

-      "I_TA=I_o*math.pi/(2*math.pi)    \n",

-      "I_Tr=math.sqrt(I_o**2*math.pi/(2*math.pi))    \n",

-      "I_s=math.sqrt(I_o**2*(1-a/180)*math.pi/(math.pi))\n",

-      "I_or=I_o\n",

-      "P=E*I_o+I_or**2*R\n",

-      "pf=(P/(V*I_s))   \n",

-      "f=50\n",

-      "w=2*math.pi*f\n",

-      "t_c=(1-a/180)*math.pi/w    \n",

-      "\n",

-      "#Results\n",

-      "print(\"\\navg o/p current=%.2f A\" %I_o)\n",

-      "print(\"avg o/p voltage=%.3f V\" %V_o)\n",

-      "print(\"avg value of thyristor current=%.2f A\" %I_TA)\n",

-      "print(\"rms value of thyristor current=%.3f A\" %I_Tr)\n",

-      "print(\"avg value of diode current=%.2f A\" %I_TA)\n",

-      "print(\"rms value of diode current=%.3f A\" %I_Tr)\n",

-      "print(\"pf=%.4f\" %pf)\n",

-      "print(\"circuit turn off time=%.2f ms\" %(t_c*1000))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "\n",

-        "avg o/p current=9.32 A\n",

-        "avg o/p voltage=193.202 V\n",

-        "avg value of thyristor current=4.66 A\n",

-        "rms value of thyristor current=6.590 A\n",

-        "avg value of diode current=4.66 A\n",

-        "rms value of diode current=6.590 A\n",

-        "pf=0.9202\n",

-        "circuit turn off time=8.33 ms\n"

-       ]

-      }

-     ],

-     "prompt_number": 32

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.38, Page No 368"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=230.0\n",

-      "V_m=math.sqrt(2)*V\n",

-      "L=0.05\n",

-      "f=50.0\n",

-      "\n",

-      "#Calculations\n",

-      "w=2*math.pi*f\n",

-      "a=30\n",

-      "i_cp=2*V_m*(1-math.cos(math.radians(a)))/(w*L)    \n",

-      "R=30.0\n",

-      "i_l=V_m/R\n",

-      "i1=i_cp+i_l    \n",

-      "i2=i_cp    \n",

-      "\n",

-      "#Results\n",

-      "print(\"peak value of circulating current=%.3f A\" %i_cp)\n",

-      "print(\"peak value of current in convertor 1=%.3f A\" %i1)\n",

-      "print(\"peak value of current in convertor 2=%.3f A\" %i2)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "peak value of circulating current=5.548 A\n",

-        "peak value of current in convertor 1=16.391 A\n",

-        "peak value of current in convertor 2=5.548 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 33

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 6.39, Page No 370"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "f=50.0\n",

-      "w=2*math.pi*f\n",

-      "R=5.0\n",

-      "L=0.05\n",

-      "\n",

-      "#Calculations\n",

-      "phi=math.degrees(math.atan(w*L/R))  \n",

-      "phi=90+math.degrees(math.atan(w*L/R))   \n",

-      "\n",

-      "#Results\n",

-      "print(\"for no current transients\")\n",

-      "print(\"triggering angle=%.2f deg\" %phi)\n",

-      "print(\"for worst transients\")\n",

-      "print(\"triggering angle=%.2f deg\" %phi)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for no current transients\n",

-        "triggering angle=162.34 deg\n",

-        "for worst transients\n",

-        "triggering angle=162.34 deg\n"

-       ]

-      }

-     ],

-     "prompt_number": 34

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Power_Electronics/Chapter7.ipynb b/_Power_Electronics/Chapter7.ipynb
deleted file mode 100755
index 726160c8..00000000
--- a/_Power_Electronics/Chapter7.ipynb
+++ /dev/null
@@ -1,1036 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 07 : Choppers"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.2, Page No 387"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "a=0.4     #duty cycle %a=T_on/T\n",

-      "V_s=230.0\n",

-      "R=10.0\n",

-      "\n",

-      "#Calculations\n",

-      "V=a*(V_s-2)    \n",

-      "V_or=math.sqrt(a*(V_s-2)**2)    \n",

-      "P_o=V_or**2/R\n",

-      "P_i=V_s*V/R\n",

-      "n=P_o*100/P_i    \n",

-      "\n",

-      "#Results\n",

-      "print(\"avg o/p voltage=%.1f V\" %V)\n",

-      "print(\"rms value of o/p voltage=%.1f V\" %V_or)\n",

-      "print(\"chopper efficiency in percentage=%.2f\" %n)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "avg o/p voltage=91.2 V\n",

-        "rms value of o/p voltage=144.2 V\n",

-        "chopper efficiency in percentage=99.13\n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.3, Page No 388"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_i=220.0\n",

-      "V_o=660.0\n",

-      "\n",

-      "#Calculations\n",

-      "a=1-V_i/V_o\n",

-      "T_on=100.0     #microsecond\n",

-      "T=T_on/a\n",

-      "T_off=T-T_on    \n",

-      "T_off=T_off/2\n",

-      "T_on=T-T_off\n",

-      "a=T_on/T\n",

-      "V_o=V_i/(1-a)\n",

-      "\n",

-      "#Results    \n",

-      "print(\"pulse width of o/p voltage=%.0f us\" %T_off)\n",

-      "print(\"\\nnew o/p voltage=%.0f V\" %V_o)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "pulse width of o/p voltage=25 us\n",

-        "\n",

-        "new o/p voltage=1320 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 2

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.4 Page No 288"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "I_1=12.0\n",

-      "I_2=16.0\n",

-      "\n",

-      "#Calculations\n",

-      "I_0=(I_1+I_2)/2\n",

-      "R=10.0\n",

-      "V_0=I_0*R\n",

-      "V_s=200.0\n",

-      "a=V_0/V_s\n",

-      "r=a/(1-a)\n",

-      "\n",

-      "#Results\n",

-      "print(\"time ratio(T_on/T_off)=%.3f\" %r)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "time ratio(T_on/T_off)=2.333\n"

-       ]

-      }

-     ],

-     "prompt_number": 3

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.5, Page No 390"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_o=660.0\n",

-      "V_s=220.0\n",

-      "\n",

-      "#Calculations\n",

-      "a=(V_o/V_s)/(1+(V_o/V_s))\n",

-      "T_on=120\n",

-      "T=T_on/a\n",

-      "T_off=T-T_on \n",

-      "T_off=3*T_off\n",

-      "T_on=T-T_off\n",

-      "a=T_on/(T_on+T_off)\n",

-      "V_o=V_s*(a/(1-a))   \n",

-      "\n",

-      "#Results\n",

-      "print(\"pulse width o/p voltage=%.0f us\" %T_off)\n",

-      "print(\"\\nnew o/p voltage=%.2f V\" %V_o)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "pulse width o/p voltage=120 us\n",

-        "\n",

-        "new o/p voltage=73.33 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 4

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.11 Page No 408"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "R=1.0\n",

-      "L=.005\n",

-      "T_a=L/R\n",

-      "T=2000*10**-6\n",

-      "E=24.0\n",

-      "V_s=220\n",

-      "T_on=600*10**-6\n",

-      "a=T_on/T\n",

-      "\n",

-      "#Calculations\n",

-      "a1=(T_a/T)*math.log(1+(E/V_s)*((math.exp(T/T_a))-1))\n",

-      "if a1<a :\n",

-      "    print(\"load current in continuous\")\n",

-      "else:\n",

-      "    print(\"load current in discont.\")\n",

-      "\n",

-      "I_o=(a*V_s-E)/R    \n",

-      "I_mx=(V_s/R)*((1-math.exp(-T_on/T_a))/(1-math.exp(-T/T_a)))-E/R    \n",

-      "I_mn=(V_s/R)*((math.exp(T_on/T_a)-1)/(math.exp(T/T_a)-1))-E/R    \n",

-      "f=1/T\n",

-      "w=2*math.pi*f\n",

-      "I1=(2*V_s/(math.sqrt(2)*math.pi)*math.sin(math.radians(180*a)))/(math.sqrt(R**2+(w*L)**2))    \n",

-      "I2=(2*V_s/(2*math.sqrt(2)*math.pi)*math.sin(math.radians(2*180*a)))/(math.sqrt(R**2+(w*L*2)**2))    \n",

-      "I3=(2*V_s/(3*math.sqrt(2)*math.pi)*math.sin(math.radians(3*180*a)))/(math.sqrt(R**2+(w*L*3)**2))    \n",

-      "I_TAV=a*(V_s-E)/R-L*(I_mx-I_mn)/(R*T)   \n",

-      "P1=I_TAV*V_s\n",

-      "P2=E*I_o\n",

-      "I_or=math.sqrt(I_o**2+I1**2+I2**2+I3**2)\n",

-      "\n",

-      "#Results\n",

-      "print(\"avg o/p current=%.2f A\" %I_o)\n",

-      "print(\"max value of steady current=%.2f A\" %I_mx)\n",

-      "print(\"min value of steady current=%.2f A\" %I_mn)\n",

-      "print(\"first harmonic current=%.4f A\" %I1)\n",

-      "print(\"second harmonic current=%.4f A\" %I2)\n",

-      "print(\"third harmonic current=%.5f A\" %I3)\n",

-      "print(\"avg supply current=%.4f A\" %I_TAV)\n",

-      "print(\"i/p power=%.2f W\" %P1)\n",

-      "print(\"power absorbed by load emf=%.0f W\" %P2)\n",

-      "print(\"power loss in resistor=%.2f W\" %(P1-P2))\n",

-      "print(\"rms value of load current=%.3f A\" %I_or)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "load current in continuous\n",

-        "avg o/p current=42.00 A\n",

-        "max value of steady current=51.46 A\n",

-        "min value of steady current=33.03 A\n",

-        "first harmonic current=5.0903 A\n",

-        "second harmonic current=1.4983 A\n",

-        "third harmonic current=0.21643 A\n",

-        "avg supply current=12.7289 A\n",

-        "i/p power=2800.35 W\n",

-        "power absorbed by load emf=1008 W\n",

-        "power loss in resistor=1792.35 W\n",

-        "rms value of load current=42.334 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 7

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.12 Page No 411"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "R=1\n",

-      "L=.001\n",

-      "V_s=220\n",

-      "E=72.0\n",

-      "f=500.0\n",

-      "T_on=800*10**-6\n",

-      "T_a=L/R\n",

-      "T=1.0/f\n",

-      "m=E/V_s\n",

-      "a=T_on/T\n",

-      "\n",

-      "#Calculations\n",

-      "a1=(T_a/T)*math.log(1+m*(math.exp(-T/T_a)-1))\n",

-      "if a1>a :\n",

-      "    print(\"load current is continuous\")\n",

-      "else:\n",

-      "    print(\"load current is discontinuous\")\n",

-      "\n",

-      "t_x=T_on+L*math.log(1+((V_s-E)/272)*(1-math.exp(-T_on/T_a)))\n",

-      " #Value of t_x wrongly calculated in the book so ans of V_o and I_o varies\n",

-      "V_o=a*V_s+(1-t_x/T)*E    \n",

-      "I_o=(V_o-E)/R    \n",

-      "I_mx=(V_s-E)/R*(1-math.exp(-T_on/T_a)) \n",

-      "\n",

-      "#Results  \n",

-      "print(\"avg o/p voltage=%.2f V\" %V_o)\n",

-      "print(\"avg o/p current=%.2f A\" %I_o) \n",

-      "print(\"max value of load current=%.1f A\" %I_mx)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "load current is discontinuous\n",

-        "avg o/p voltage=121.77 V\n",

-        "avg o/p current=49.77 A\n",

-        "max value of load current=81.5 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 10

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.13, Page No 412"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "a=0.2\n",

-      "V_s=500\n",

-      "E=a*V_s\n",

-      "L=0.06\n",

-      "I=10\n",

-      "\n",

-      "#Calculations\n",

-      "T_on=(L*I)/(V_s-E)\n",

-      "f=a/T_on    \n",

-      "\n",

-      "#Results\n",

-      "print(\"chopping freq=%.2f Hz\" %f)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "chopping freq=133.33 Hz\n"

-       ]

-      }

-     ],

-     "prompt_number": 11

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.14 Page No 412"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "a=0.5\n",

-      "pu=0.1 #pu ripple\n",

-      "\n",

-      "#Calculations\n",

-      " #x=T/T_a\n",

-      " #y=exp(-a*x)\n",

-      "y=(1-pu)/(1+pu)\n",

-      " #after solving\n",

-      "x=math.log(1/y)/a\n",

-      "f=1000\n",

-      "T=1/f\n",

-      "T_a=T/x\n",

-      "R=2\n",

-      "L=R*T_a\n",

-      "Li=0.002\n",

-      "Le=L-Li    \n",

-      "\n",

-      "#Results\n",

-      "print(\"external inductance=%.3f mH\" %(Le*1000))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "external inductance=-2.000 mH\n"

-       ]

-      }

-     ],

-     "prompt_number": 12

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.15 Page No 414"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "R=10.0\n",

-      "L=0.015\n",

-      "T_a=L/R\n",

-      "f=1250.0\n",

-      "T=1.0/f\n",

-      "a=0.5\n",

-      "T_on=a*T\n",

-      "V_s=220.0\n",

-      "\n",

-      "#Calculations\n",

-      "I_mx=(V_s/R)*((1-math.exp(-T_on/T_a))/(1-math.exp(-T/T_a)))   \n",

-      "I_mn=(V_s/R)*((math.exp(T_on/T_a)-1)/(math.exp(T/T_a)-1))    \n",

-      "dI=I_mx-I_mn    \n",

-      "V_o=a*V_s\n",

-      "I_o=V_o/R    \n",

-      "I_or=math.sqrt(I_mx**2+dI**2/3+I_mx*dI)    \n",

-      "I_chr=math.sqrt(a)*I_or \n",

-      "\n",

-      "#Results\n",

-      "print(\"Max value of ripple current=%.2f A\" %dI)\n",

-      "print(\"Max value of load current=%.3f A\" %I_mx)\n",

-      "print(\"Min value of load current=%.2f A\" %I_mn)\n",

-      "print(\"Avg value of load current=%.2f A\" %I_o)   \n",

-      "print(\"rms value of load current=%.2f A\" %I_or)\n",

-      "print(\"rms value of chopper current=%.2f A\" %I_chr)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Max value of ripple current=2.92 A\n",

-        "Max value of load current=12.458 A\n",

-        "Min value of load current=9.54 A\n",

-        "Avg value of load current=11.00 A\n",

-        "rms value of load current=13.94 A\n",

-        "rms value of chopper current=9.86 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 14

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.17 Page No 417"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "L=0.0016\n",

-      "C=4*10**-6\n",

-      "\n",

-      "#Calculations\n",

-      "w=1/math.sqrt(L*C)\n",

-      "t=math.pi/w    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"time for which current flows=%.2f us\" %(t*10**6))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "time for which current flows=251.33 us\n"

-       ]

-      }

-     ],

-     "prompt_number": 15

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.18, Page No 424"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "t_q=20.0*10**-6\n",

-      "dt=20.0*10**-6\n",

-      "\n",

-      "#Calculations\n",

-      "t_c=t_q+dt\n",

-      "I_0=60.0\n",

-      "V_s=60.0\n",

-      "C=t_c*I_0/V_s \n",

-      "\n",

-      "#Results   \n",

-      "print(\"value of commutating capacitor=%.0f uF\" %(C*10**6))\n",

-      "\n",

-      "L1=(V_s/I_0)**2*C\n",

-      "L2=(2*t_c/math.pi)**2/C\n",

-      "if L1>L2 :\n",

-      "    print(\"value of commutating inductor=%.0f uH\" %(L1*10**6))\n",

-      "else:\n",

-      "    print(\"value of commutating inductor=%.0f uH\" %(L2*10**6))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "value of commutating capacitor=40 uF\n",

-        "value of commutating inductor=40 uH\n"

-       ]

-      }

-     ],

-     "prompt_number": 19

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.19, Page No 424"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "t=100.0*10**-6\n",

-      "R=10.0\n",

-      "\n",

-      "#Calculations\n",

-      " #V_s*(1-2*math.exp(-t/(R*C)))=0\n",

-      "C=-t/(R*math.log(1.0/2))    \n",

-      "L=(4/9.0)*C*R**2    \n",

-      "L=(1.0/4)*C*R**2    \n",

-      "\n",

-      "#Results\n",

-      "print(\"Value of comutating component C=%.3f uF\" %(C*10**6))\n",

-      "print(\"max permissible current through SCR is 2.5 times load current\")\n",

-      "print(\"value of comutating component L=%.1f uH\" %(L*10**6))\n",

-      "print(\"max permissible current through SCR is 1.5 times peak diode current\")\n",

-      "print(\"value of comutating component L=%.2f uH\" %(L*10**6))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Value of comutating component C=14.427 uF\n",

-        "max permissible current through SCR is 2.5 times load current\n",

-        "value of comutating component L=360.7 uH\n",

-        "max permissible current through SCR is 1.5 times peak diode current\n",

-        "value of comutating component L=360.67 uH\n"

-       ]

-      }

-     ],

-     "prompt_number": 20

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.20, Page No 426"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "T_on=800.0*10**-6\n",

-      "V_s=220.0\n",

-      "I_o=80.0\n",

-      "C=50*10**-6\n",

-      "\n",

-      "#Calculations\n",

-      "T=T_on+2*V_s*C/I_o    \n",

-      "L=20*10**-6\n",

-      "C=50*10**-6\n",

-      "i_T1=I_o+V_s*math.sqrt(C/L)    \n",

-      "i_TA=I_o    \n",

-      "t_c=C*V_s/I_o    \n",

-      "t_c1=(math.pi/2)*math.sqrt(L*C)    \n",

-      "t=150*10**-6\n",

-      "v_c=I_o*t/C-V_s  \n",

-      "\n",

-      "#Results  \n",

-      "print(\"effective on period=%.0f us\" %(T*10**6))\n",

-      "print(\"peak current through main thyristor=%.2f A\" %i_T1)\n",

-      "print(\"peak current through auxillery thyristor=%.0f A\" %i_TA)\n",

-      "print(\"turn off time for main thyristor=%.1f us\" %(t_c*10**6))\n",

-      "print(\"turn off time for auxillery thyristor=%.3f us\" %(t_c1*10**6))\n",

-      "print(\"total commutation interval=%.0f us\" %(2*t_c*10**6))\n",

-      "print(\"capacitor voltage=%.0f V\" %v_c)\n",

-      "print(\"time nedded to recharge the capacitor=%.0f us\" %(2*V_s*C/I_o*10**6))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for firing angle = 30deg\n",

-        "avg output voltage=232.509 V\n",

-        "for firing angle = 60deg\n",

-        "avg output voltage=133.65 V\n",

-        "avg current rating=12 A\n",

-        "rms current rating=20.785 A\n",

-        "PIV of SCR=565.7 V\n",

-        "power dissipated=16.8 W\n"

-       ]

-      }

-     ],

-     "prompt_number": 122

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.21, Page No 427"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "I_o=260.0\n",

-      "V_s=220.0\n",

-      "fos=2 #factor of safety\n",

-      "\n",

-      "#Calculations\n",

-      "t_off=18*10**-6\n",

-      "t_c=2*t_off\n",

-      "C=t_c*I_o/V_s    \n",

-      "L=(V_s/(0.8*I_o))**2*C    \n",

-      "f=400\n",

-      "a_mn=math.pi*f*math.sqrt(L*C)\n",

-      "V_omn=V_s*(a_mn+2*f*t_c)    \n",

-      "V_omx=V_s    \n",

-      "\n",

-      "#Results\n",

-      "print(\"Value of C=%.3f uF\" %(C*10**6))\n",

-      "print(\"value of L=%.3f uH\" %(L*10**6))\n",

-      "print(\"min value of o/p voltage=%.3f V\" %V_omn)\n",

-      "print(\"max value of o/p voltage=%.0f V\" %V_omx)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "firing angle delay=47.461 deg\n",

-        "pf=0.646\n",

-        "firing angle delay=127.71 deg\n"

-       ]

-      }

-     ],

-     "prompt_number": "*"

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.22, Page No 434"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "x=2.0\n",

-      "t_q=30*10**-6\n",

-      "dt=30*10**-6\n",

-      "t_c=t_q+dt\n",

-      "V_s=230.0\n",

-      "I_o=200.0\n",

-      "\n",

-      "#Calculations\n",

-      "L=V_s*t_c/(x*I_o*(math.pi-2*math.asin(1/x)))    \n",

-      "C=x*I_o*t_c/(V_s*(math.pi-2*math.asin(1/x)))    \n",

-      "V_cp=V_s+I_o*math.sqrt(L/C)    \n",

-      "I_cp=x*I_o    \n",

-      "x=3\n",

-      "L=V_s*t_c/(x*I_o*(math.pi-2*math.asin(1/x)))   \n",

-      "C=x*I_o*t_c/(V_s*(math.pi-2*math.asin(1/x)))    \n",

-      "V_cp=V_s+I_o*math.sqrt(L/C)    \n",

-      "I_cp=x*I_o    \n",

-      "\n",

-      "#Results\n",

-      "print(\"value of commutating inductor=%.3f uH\" %(L*10**6))\n",

-      "print(\"value of commutating capacitor=%.3f uF\" %(C*10**6))\n",

-      "print(\"peak capacitor voltage=%.0f V\" %V_cp)\n",

-      "print(\"peak commutataing current=%.0f A\" %I_cp)\n",

-      "print(\"value of commutating inductor=%.3f uH\" %(L*10**6))\n",

-      "print(\"value of commutating capacitor=%.3f uF\" %(C*10**6))\n",

-      "print(\"peak capacitor voltage=%.2f V\" %V_cp)\n",

-      "print(\"peak commutataing current=%.0f A\" %I_cp)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "value of commutating inductor=7.321 uH\n",

-        "value of commutating capacitor=49.822 uF\n",

-        "peak capacitor voltage=307 V\n",

-        "peak commutataing current=600 A\n",

-        "value of commutating inductor=7.321 uH\n",

-        "value of commutating capacitor=49.822 uF\n",

-        "peak capacitor voltage=306.67 V\n",

-        "peak commutataing current=600 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 25

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.23, Page No 434"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variablesV_s=230\n",

-      "C=50*10**-6\n",

-      "L=20*10**-6\n",

-      "I_cp=V_s*math.sqrt(C/L)\n",

-      "I_o=200\n",

-      "x=I_cp/I_o\n",

-      "\n",

-      "#Calculations\n",

-      "t_c=(math.pi-2*math.asin(1/x))*math.sqrt(C*L)   \n",

-      "th1=math.degrees(math.asin(1.0/x))\n",

-      "t=(5*math.pi/2-th1*math.pi/180)*math.sqrt(L*C)+C*V_s*(1-math.cos(math.radians(th1)))/I_o    \n",

-      "t=(math.pi-th1*math.pi/180)*math.sqrt(L*C)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"turn off time of main thyristor=%.2f us\" %(t_c*10**6))\n",

-      "print(\"total commutation interval=%.3f us\" %(t*10**6))\n",

-      "print(\"turn off time of auxillery thyristor=%.3f us\" %(t*10**6))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "turn off time of main thyristor=62.52 us\n",

-        "total commutation interval=80.931 us\n",

-        "turn off time of auxillery thyristor=80.931 us\n"

-       ]

-      }

-     ],

-     "prompt_number": 27

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.24, Page No 440"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "tc=0.006\n",

-      "R=10.0\n",

-      "L=R*tc\n",

-      "f=2000.0\n",

-      "\n",

-      "#Calculations\n",

-      "T=1/f\n",

-      "V_o=50.0\n",

-      "V_s=100.0\n",

-      "a=V_o/V_s\n",

-      "T_on=a*T\n",

-      "T_off=T-T_on\n",

-      "dI=V_o*T_off/L\n",

-      "I_o=V_o/R\n",

-      "I2=I_o+dI/2    \n",

-      "I1=I_o-dI/2    \n",

-      "\n",

-      "#Results\n",

-      "print(\"max value of load current=%.3f A\" %I2)\n",

-      "print(\"min value of load current=%.3f A\" %I1)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "max value of load current=5.104 A\n",

-        "min value of load current=4.896 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 28

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.27, Page No 443"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "I_a=30.0\n",

-      "r_a=.5\n",

-      "V_s=220.0\n",

-      "\n",

-      "#Calculations\n",

-      "a=I_a*r_a/V_s    \n",

-      "a=1\n",

-      "k=.1 #V/rpm\n",

-      "N=(a*V_s-I_a*r_a)/k    \n",

-      "\n",

-      "#Results\n",

-      "print(\"min value of duty cycle=%.3f\" %a)\n",

-      "print(\"min Value of speed control=%.0f rpm\" %0)\n",

-      "print(\"max value of duty cycle=%.0f\" %a)\n",

-      "print(\"max value of speed control=%.0f rpm\" %N)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "min value of duty cycle=1.000\n",

-        "min Value of speed control=0 rpm\n",

-        "max value of duty cycle=1\n",

-        "max value of speed control=2050 rpm\n"

-       ]

-      }

-     ],

-     "prompt_number": 29

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.28, Page No 444"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_t=72.0\n",

-      "I_a=200.0\n",

-      "r_a=0.045\n",

-      "N=2500.0\n",

-      "\n",

-      "#Calculations\n",

-      "k=(V_t-I_a*r_a)/N\n",

-      "E_a=k*1000\n",

-      "L=.007\n",

-      "Rm=.045\n",

-      "Rb=0.065\n",

-      "R=Rm+Rb\n",

-      "T_a=L/R\n",

-      "I_mx=230\n",

-      "I_mn=180\n",

-      "T_on=-T_a*math.log(-((V_t-E_a)/R-I_mx)/((I_mn)-(V_t-E_a)/R))\n",

-      "R=Rm\n",

-      "T_a=L/R\n",

-      "T_off=-T_a*math.log(-((-E_a)/R-I_mn)/((I_mx)-(-E_a)/R))\n",

-      "T=T_on+T_off\n",

-      "f=1/T    \n",

-      "a=T_on/T \n",

-      "\n",

-      "#Results\n",

-      "print(\"chopping freq=%.1f Hz\" %f)  \n",

-      "print(\"duty cycle ratio=%.3f\" %a)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "chopping freq=40.5 Hz\n",

-        "\n",

-        "duty cycle ratio=0.588\n"

-       ]

-      }

-     ],

-     "prompt_number": 30

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.29, Page No 445"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variablesI_mx=425\n",

-      "I_lt=180.0     #lower limit of current pulsation\n",

-      "I_mn=I_mx-I_lt\n",

-      "T_on=0.014\n",

-      "T_off=0.011\n",

-      "\n",

-      "#Calculations\n",

-      "T=T_on+T_off\n",

-      "T_a=.0635\n",

-      "a=T_on/T\n",

-      "V=(I_mx-I_mn*math.exp(-T_on/T_a))/(1-math.exp(-T_on/T_a))\n",

-      "a=.5\n",

-      "I_mn=(I_mx-V*(1-math.exp(-T_on/T_a)))/(math.exp(-T_on/T_a))\n",

-      "T=I_mx-I_mn    \n",

-      "T=T_on/a\n",

-      "f=1/T    \n",

-      "\n",

-      "#Results\n",

-      "print(\"higher limit of current pulsation=%.0f A\" %T)\n",

-      "print(\"chopping freq=%.3f Hz\" %f)\n",

-      "print(\"duty cycle ratio=%.2f\" %a)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "higher limit of current pulsation=0 A\n",

-        "chopping freq=35.714 Hz\n",

-        "duty cycle ratio=0.50\n"

-       ]

-      }

-     ],

-     "prompt_number": 32

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Power_Electronics/Chapter7_1.ipynb b/_Power_Electronics/Chapter7_1.ipynb
deleted file mode 100755
index 726160c8..00000000
--- a/_Power_Electronics/Chapter7_1.ipynb
+++ /dev/null
@@ -1,1036 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 07 : Choppers"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.2, Page No 387"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "a=0.4     #duty cycle %a=T_on/T\n",

-      "V_s=230.0\n",

-      "R=10.0\n",

-      "\n",

-      "#Calculations\n",

-      "V=a*(V_s-2)    \n",

-      "V_or=math.sqrt(a*(V_s-2)**2)    \n",

-      "P_o=V_or**2/R\n",

-      "P_i=V_s*V/R\n",

-      "n=P_o*100/P_i    \n",

-      "\n",

-      "#Results\n",

-      "print(\"avg o/p voltage=%.1f V\" %V)\n",

-      "print(\"rms value of o/p voltage=%.1f V\" %V_or)\n",

-      "print(\"chopper efficiency in percentage=%.2f\" %n)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "avg o/p voltage=91.2 V\n",

-        "rms value of o/p voltage=144.2 V\n",

-        "chopper efficiency in percentage=99.13\n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.3, Page No 388"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_i=220.0\n",

-      "V_o=660.0\n",

-      "\n",

-      "#Calculations\n",

-      "a=1-V_i/V_o\n",

-      "T_on=100.0     #microsecond\n",

-      "T=T_on/a\n",

-      "T_off=T-T_on    \n",

-      "T_off=T_off/2\n",

-      "T_on=T-T_off\n",

-      "a=T_on/T\n",

-      "V_o=V_i/(1-a)\n",

-      "\n",

-      "#Results    \n",

-      "print(\"pulse width of o/p voltage=%.0f us\" %T_off)\n",

-      "print(\"\\nnew o/p voltage=%.0f V\" %V_o)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "pulse width of o/p voltage=25 us\n",

-        "\n",

-        "new o/p voltage=1320 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 2

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.4 Page No 288"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "I_1=12.0\n",

-      "I_2=16.0\n",

-      "\n",

-      "#Calculations\n",

-      "I_0=(I_1+I_2)/2\n",

-      "R=10.0\n",

-      "V_0=I_0*R\n",

-      "V_s=200.0\n",

-      "a=V_0/V_s\n",

-      "r=a/(1-a)\n",

-      "\n",

-      "#Results\n",

-      "print(\"time ratio(T_on/T_off)=%.3f\" %r)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "time ratio(T_on/T_off)=2.333\n"

-       ]

-      }

-     ],

-     "prompt_number": 3

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.5, Page No 390"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_o=660.0\n",

-      "V_s=220.0\n",

-      "\n",

-      "#Calculations\n",

-      "a=(V_o/V_s)/(1+(V_o/V_s))\n",

-      "T_on=120\n",

-      "T=T_on/a\n",

-      "T_off=T-T_on \n",

-      "T_off=3*T_off\n",

-      "T_on=T-T_off\n",

-      "a=T_on/(T_on+T_off)\n",

-      "V_o=V_s*(a/(1-a))   \n",

-      "\n",

-      "#Results\n",

-      "print(\"pulse width o/p voltage=%.0f us\" %T_off)\n",

-      "print(\"\\nnew o/p voltage=%.2f V\" %V_o)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "pulse width o/p voltage=120 us\n",

-        "\n",

-        "new o/p voltage=73.33 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 4

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.11 Page No 408"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "R=1.0\n",

-      "L=.005\n",

-      "T_a=L/R\n",

-      "T=2000*10**-6\n",

-      "E=24.0\n",

-      "V_s=220\n",

-      "T_on=600*10**-6\n",

-      "a=T_on/T\n",

-      "\n",

-      "#Calculations\n",

-      "a1=(T_a/T)*math.log(1+(E/V_s)*((math.exp(T/T_a))-1))\n",

-      "if a1<a :\n",

-      "    print(\"load current in continuous\")\n",

-      "else:\n",

-      "    print(\"load current in discont.\")\n",

-      "\n",

-      "I_o=(a*V_s-E)/R    \n",

-      "I_mx=(V_s/R)*((1-math.exp(-T_on/T_a))/(1-math.exp(-T/T_a)))-E/R    \n",

-      "I_mn=(V_s/R)*((math.exp(T_on/T_a)-1)/(math.exp(T/T_a)-1))-E/R    \n",

-      "f=1/T\n",

-      "w=2*math.pi*f\n",

-      "I1=(2*V_s/(math.sqrt(2)*math.pi)*math.sin(math.radians(180*a)))/(math.sqrt(R**2+(w*L)**2))    \n",

-      "I2=(2*V_s/(2*math.sqrt(2)*math.pi)*math.sin(math.radians(2*180*a)))/(math.sqrt(R**2+(w*L*2)**2))    \n",

-      "I3=(2*V_s/(3*math.sqrt(2)*math.pi)*math.sin(math.radians(3*180*a)))/(math.sqrt(R**2+(w*L*3)**2))    \n",

-      "I_TAV=a*(V_s-E)/R-L*(I_mx-I_mn)/(R*T)   \n",

-      "P1=I_TAV*V_s\n",

-      "P2=E*I_o\n",

-      "I_or=math.sqrt(I_o**2+I1**2+I2**2+I3**2)\n",

-      "\n",

-      "#Results\n",

-      "print(\"avg o/p current=%.2f A\" %I_o)\n",

-      "print(\"max value of steady current=%.2f A\" %I_mx)\n",

-      "print(\"min value of steady current=%.2f A\" %I_mn)\n",

-      "print(\"first harmonic current=%.4f A\" %I1)\n",

-      "print(\"second harmonic current=%.4f A\" %I2)\n",

-      "print(\"third harmonic current=%.5f A\" %I3)\n",

-      "print(\"avg supply current=%.4f A\" %I_TAV)\n",

-      "print(\"i/p power=%.2f W\" %P1)\n",

-      "print(\"power absorbed by load emf=%.0f W\" %P2)\n",

-      "print(\"power loss in resistor=%.2f W\" %(P1-P2))\n",

-      "print(\"rms value of load current=%.3f A\" %I_or)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "load current in continuous\n",

-        "avg o/p current=42.00 A\n",

-        "max value of steady current=51.46 A\n",

-        "min value of steady current=33.03 A\n",

-        "first harmonic current=5.0903 A\n",

-        "second harmonic current=1.4983 A\n",

-        "third harmonic current=0.21643 A\n",

-        "avg supply current=12.7289 A\n",

-        "i/p power=2800.35 W\n",

-        "power absorbed by load emf=1008 W\n",

-        "power loss in resistor=1792.35 W\n",

-        "rms value of load current=42.334 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 7

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.12 Page No 411"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "R=1\n",

-      "L=.001\n",

-      "V_s=220\n",

-      "E=72.0\n",

-      "f=500.0\n",

-      "T_on=800*10**-6\n",

-      "T_a=L/R\n",

-      "T=1.0/f\n",

-      "m=E/V_s\n",

-      "a=T_on/T\n",

-      "\n",

-      "#Calculations\n",

-      "a1=(T_a/T)*math.log(1+m*(math.exp(-T/T_a)-1))\n",

-      "if a1>a :\n",

-      "    print(\"load current is continuous\")\n",

-      "else:\n",

-      "    print(\"load current is discontinuous\")\n",

-      "\n",

-      "t_x=T_on+L*math.log(1+((V_s-E)/272)*(1-math.exp(-T_on/T_a)))\n",

-      " #Value of t_x wrongly calculated in the book so ans of V_o and I_o varies\n",

-      "V_o=a*V_s+(1-t_x/T)*E    \n",

-      "I_o=(V_o-E)/R    \n",

-      "I_mx=(V_s-E)/R*(1-math.exp(-T_on/T_a)) \n",

-      "\n",

-      "#Results  \n",

-      "print(\"avg o/p voltage=%.2f V\" %V_o)\n",

-      "print(\"avg o/p current=%.2f A\" %I_o) \n",

-      "print(\"max value of load current=%.1f A\" %I_mx)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "load current is discontinuous\n",

-        "avg o/p voltage=121.77 V\n",

-        "avg o/p current=49.77 A\n",

-        "max value of load current=81.5 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 10

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.13, Page No 412"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "a=0.2\n",

-      "V_s=500\n",

-      "E=a*V_s\n",

-      "L=0.06\n",

-      "I=10\n",

-      "\n",

-      "#Calculations\n",

-      "T_on=(L*I)/(V_s-E)\n",

-      "f=a/T_on    \n",

-      "\n",

-      "#Results\n",

-      "print(\"chopping freq=%.2f Hz\" %f)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "chopping freq=133.33 Hz\n"

-       ]

-      }

-     ],

-     "prompt_number": 11

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.14 Page No 412"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "a=0.5\n",

-      "pu=0.1 #pu ripple\n",

-      "\n",

-      "#Calculations\n",

-      " #x=T/T_a\n",

-      " #y=exp(-a*x)\n",

-      "y=(1-pu)/(1+pu)\n",

-      " #after solving\n",

-      "x=math.log(1/y)/a\n",

-      "f=1000\n",

-      "T=1/f\n",

-      "T_a=T/x\n",

-      "R=2\n",

-      "L=R*T_a\n",

-      "Li=0.002\n",

-      "Le=L-Li    \n",

-      "\n",

-      "#Results\n",

-      "print(\"external inductance=%.3f mH\" %(Le*1000))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "external inductance=-2.000 mH\n"

-       ]

-      }

-     ],

-     "prompt_number": 12

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.15 Page No 414"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "R=10.0\n",

-      "L=0.015\n",

-      "T_a=L/R\n",

-      "f=1250.0\n",

-      "T=1.0/f\n",

-      "a=0.5\n",

-      "T_on=a*T\n",

-      "V_s=220.0\n",

-      "\n",

-      "#Calculations\n",

-      "I_mx=(V_s/R)*((1-math.exp(-T_on/T_a))/(1-math.exp(-T/T_a)))   \n",

-      "I_mn=(V_s/R)*((math.exp(T_on/T_a)-1)/(math.exp(T/T_a)-1))    \n",

-      "dI=I_mx-I_mn    \n",

-      "V_o=a*V_s\n",

-      "I_o=V_o/R    \n",

-      "I_or=math.sqrt(I_mx**2+dI**2/3+I_mx*dI)    \n",

-      "I_chr=math.sqrt(a)*I_or \n",

-      "\n",

-      "#Results\n",

-      "print(\"Max value of ripple current=%.2f A\" %dI)\n",

-      "print(\"Max value of load current=%.3f A\" %I_mx)\n",

-      "print(\"Min value of load current=%.2f A\" %I_mn)\n",

-      "print(\"Avg value of load current=%.2f A\" %I_o)   \n",

-      "print(\"rms value of load current=%.2f A\" %I_or)\n",

-      "print(\"rms value of chopper current=%.2f A\" %I_chr)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Max value of ripple current=2.92 A\n",

-        "Max value of load current=12.458 A\n",

-        "Min value of load current=9.54 A\n",

-        "Avg value of load current=11.00 A\n",

-        "rms value of load current=13.94 A\n",

-        "rms value of chopper current=9.86 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 14

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.17 Page No 417"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "L=0.0016\n",

-      "C=4*10**-6\n",

-      "\n",

-      "#Calculations\n",

-      "w=1/math.sqrt(L*C)\n",

-      "t=math.pi/w    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"time for which current flows=%.2f us\" %(t*10**6))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "time for which current flows=251.33 us\n"

-       ]

-      }

-     ],

-     "prompt_number": 15

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.18, Page No 424"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "t_q=20.0*10**-6\n",

-      "dt=20.0*10**-6\n",

-      "\n",

-      "#Calculations\n",

-      "t_c=t_q+dt\n",

-      "I_0=60.0\n",

-      "V_s=60.0\n",

-      "C=t_c*I_0/V_s \n",

-      "\n",

-      "#Results   \n",

-      "print(\"value of commutating capacitor=%.0f uF\" %(C*10**6))\n",

-      "\n",

-      "L1=(V_s/I_0)**2*C\n",

-      "L2=(2*t_c/math.pi)**2/C\n",

-      "if L1>L2 :\n",

-      "    print(\"value of commutating inductor=%.0f uH\" %(L1*10**6))\n",

-      "else:\n",

-      "    print(\"value of commutating inductor=%.0f uH\" %(L2*10**6))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "value of commutating capacitor=40 uF\n",

-        "value of commutating inductor=40 uH\n"

-       ]

-      }

-     ],

-     "prompt_number": 19

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.19, Page No 424"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "t=100.0*10**-6\n",

-      "R=10.0\n",

-      "\n",

-      "#Calculations\n",

-      " #V_s*(1-2*math.exp(-t/(R*C)))=0\n",

-      "C=-t/(R*math.log(1.0/2))    \n",

-      "L=(4/9.0)*C*R**2    \n",

-      "L=(1.0/4)*C*R**2    \n",

-      "\n",

-      "#Results\n",

-      "print(\"Value of comutating component C=%.3f uF\" %(C*10**6))\n",

-      "print(\"max permissible current through SCR is 2.5 times load current\")\n",

-      "print(\"value of comutating component L=%.1f uH\" %(L*10**6))\n",

-      "print(\"max permissible current through SCR is 1.5 times peak diode current\")\n",

-      "print(\"value of comutating component L=%.2f uH\" %(L*10**6))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Value of comutating component C=14.427 uF\n",

-        "max permissible current through SCR is 2.5 times load current\n",

-        "value of comutating component L=360.7 uH\n",

-        "max permissible current through SCR is 1.5 times peak diode current\n",

-        "value of comutating component L=360.67 uH\n"

-       ]

-      }

-     ],

-     "prompt_number": 20

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.20, Page No 426"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "T_on=800.0*10**-6\n",

-      "V_s=220.0\n",

-      "I_o=80.0\n",

-      "C=50*10**-6\n",

-      "\n",

-      "#Calculations\n",

-      "T=T_on+2*V_s*C/I_o    \n",

-      "L=20*10**-6\n",

-      "C=50*10**-6\n",

-      "i_T1=I_o+V_s*math.sqrt(C/L)    \n",

-      "i_TA=I_o    \n",

-      "t_c=C*V_s/I_o    \n",

-      "t_c1=(math.pi/2)*math.sqrt(L*C)    \n",

-      "t=150*10**-6\n",

-      "v_c=I_o*t/C-V_s  \n",

-      "\n",

-      "#Results  \n",

-      "print(\"effective on period=%.0f us\" %(T*10**6))\n",

-      "print(\"peak current through main thyristor=%.2f A\" %i_T1)\n",

-      "print(\"peak current through auxillery thyristor=%.0f A\" %i_TA)\n",

-      "print(\"turn off time for main thyristor=%.1f us\" %(t_c*10**6))\n",

-      "print(\"turn off time for auxillery thyristor=%.3f us\" %(t_c1*10**6))\n",

-      "print(\"total commutation interval=%.0f us\" %(2*t_c*10**6))\n",

-      "print(\"capacitor voltage=%.0f V\" %v_c)\n",

-      "print(\"time nedded to recharge the capacitor=%.0f us\" %(2*V_s*C/I_o*10**6))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for firing angle = 30deg\n",

-        "avg output voltage=232.509 V\n",

-        "for firing angle = 60deg\n",

-        "avg output voltage=133.65 V\n",

-        "avg current rating=12 A\n",

-        "rms current rating=20.785 A\n",

-        "PIV of SCR=565.7 V\n",

-        "power dissipated=16.8 W\n"

-       ]

-      }

-     ],

-     "prompt_number": 122

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.21, Page No 427"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "I_o=260.0\n",

-      "V_s=220.0\n",

-      "fos=2 #factor of safety\n",

-      "\n",

-      "#Calculations\n",

-      "t_off=18*10**-6\n",

-      "t_c=2*t_off\n",

-      "C=t_c*I_o/V_s    \n",

-      "L=(V_s/(0.8*I_o))**2*C    \n",

-      "f=400\n",

-      "a_mn=math.pi*f*math.sqrt(L*C)\n",

-      "V_omn=V_s*(a_mn+2*f*t_c)    \n",

-      "V_omx=V_s    \n",

-      "\n",

-      "#Results\n",

-      "print(\"Value of C=%.3f uF\" %(C*10**6))\n",

-      "print(\"value of L=%.3f uH\" %(L*10**6))\n",

-      "print(\"min value of o/p voltage=%.3f V\" %V_omn)\n",

-      "print(\"max value of o/p voltage=%.0f V\" %V_omx)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "firing angle delay=47.461 deg\n",

-        "pf=0.646\n",

-        "firing angle delay=127.71 deg\n"

-       ]

-      }

-     ],

-     "prompt_number": "*"

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.22, Page No 434"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "x=2.0\n",

-      "t_q=30*10**-6\n",

-      "dt=30*10**-6\n",

-      "t_c=t_q+dt\n",

-      "V_s=230.0\n",

-      "I_o=200.0\n",

-      "\n",

-      "#Calculations\n",

-      "L=V_s*t_c/(x*I_o*(math.pi-2*math.asin(1/x)))    \n",

-      "C=x*I_o*t_c/(V_s*(math.pi-2*math.asin(1/x)))    \n",

-      "V_cp=V_s+I_o*math.sqrt(L/C)    \n",

-      "I_cp=x*I_o    \n",

-      "x=3\n",

-      "L=V_s*t_c/(x*I_o*(math.pi-2*math.asin(1/x)))   \n",

-      "C=x*I_o*t_c/(V_s*(math.pi-2*math.asin(1/x)))    \n",

-      "V_cp=V_s+I_o*math.sqrt(L/C)    \n",

-      "I_cp=x*I_o    \n",

-      "\n",

-      "#Results\n",

-      "print(\"value of commutating inductor=%.3f uH\" %(L*10**6))\n",

-      "print(\"value of commutating capacitor=%.3f uF\" %(C*10**6))\n",

-      "print(\"peak capacitor voltage=%.0f V\" %V_cp)\n",

-      "print(\"peak commutataing current=%.0f A\" %I_cp)\n",

-      "print(\"value of commutating inductor=%.3f uH\" %(L*10**6))\n",

-      "print(\"value of commutating capacitor=%.3f uF\" %(C*10**6))\n",

-      "print(\"peak capacitor voltage=%.2f V\" %V_cp)\n",

-      "print(\"peak commutataing current=%.0f A\" %I_cp)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "value of commutating inductor=7.321 uH\n",

-        "value of commutating capacitor=49.822 uF\n",

-        "peak capacitor voltage=307 V\n",

-        "peak commutataing current=600 A\n",

-        "value of commutating inductor=7.321 uH\n",

-        "value of commutating capacitor=49.822 uF\n",

-        "peak capacitor voltage=306.67 V\n",

-        "peak commutataing current=600 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 25

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.23, Page No 434"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variablesV_s=230\n",

-      "C=50*10**-6\n",

-      "L=20*10**-6\n",

-      "I_cp=V_s*math.sqrt(C/L)\n",

-      "I_o=200\n",

-      "x=I_cp/I_o\n",

-      "\n",

-      "#Calculations\n",

-      "t_c=(math.pi-2*math.asin(1/x))*math.sqrt(C*L)   \n",

-      "th1=math.degrees(math.asin(1.0/x))\n",

-      "t=(5*math.pi/2-th1*math.pi/180)*math.sqrt(L*C)+C*V_s*(1-math.cos(math.radians(th1)))/I_o    \n",

-      "t=(math.pi-th1*math.pi/180)*math.sqrt(L*C)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"turn off time of main thyristor=%.2f us\" %(t_c*10**6))\n",

-      "print(\"total commutation interval=%.3f us\" %(t*10**6))\n",

-      "print(\"turn off time of auxillery thyristor=%.3f us\" %(t*10**6))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "turn off time of main thyristor=62.52 us\n",

-        "total commutation interval=80.931 us\n",

-        "turn off time of auxillery thyristor=80.931 us\n"

-       ]

-      }

-     ],

-     "prompt_number": 27

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.24, Page No 440"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "tc=0.006\n",

-      "R=10.0\n",

-      "L=R*tc\n",

-      "f=2000.0\n",

-      "\n",

-      "#Calculations\n",

-      "T=1/f\n",

-      "V_o=50.0\n",

-      "V_s=100.0\n",

-      "a=V_o/V_s\n",

-      "T_on=a*T\n",

-      "T_off=T-T_on\n",

-      "dI=V_o*T_off/L\n",

-      "I_o=V_o/R\n",

-      "I2=I_o+dI/2    \n",

-      "I1=I_o-dI/2    \n",

-      "\n",

-      "#Results\n",

-      "print(\"max value of load current=%.3f A\" %I2)\n",

-      "print(\"min value of load current=%.3f A\" %I1)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "max value of load current=5.104 A\n",

-        "min value of load current=4.896 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 28

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.27, Page No 443"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "I_a=30.0\n",

-      "r_a=.5\n",

-      "V_s=220.0\n",

-      "\n",

-      "#Calculations\n",

-      "a=I_a*r_a/V_s    \n",

-      "a=1\n",

-      "k=.1 #V/rpm\n",

-      "N=(a*V_s-I_a*r_a)/k    \n",

-      "\n",

-      "#Results\n",

-      "print(\"min value of duty cycle=%.3f\" %a)\n",

-      "print(\"min Value of speed control=%.0f rpm\" %0)\n",

-      "print(\"max value of duty cycle=%.0f\" %a)\n",

-      "print(\"max value of speed control=%.0f rpm\" %N)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "min value of duty cycle=1.000\n",

-        "min Value of speed control=0 rpm\n",

-        "max value of duty cycle=1\n",

-        "max value of speed control=2050 rpm\n"

-       ]

-      }

-     ],

-     "prompt_number": 29

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.28, Page No 444"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_t=72.0\n",

-      "I_a=200.0\n",

-      "r_a=0.045\n",

-      "N=2500.0\n",

-      "\n",

-      "#Calculations\n",

-      "k=(V_t-I_a*r_a)/N\n",

-      "E_a=k*1000\n",

-      "L=.007\n",

-      "Rm=.045\n",

-      "Rb=0.065\n",

-      "R=Rm+Rb\n",

-      "T_a=L/R\n",

-      "I_mx=230\n",

-      "I_mn=180\n",

-      "T_on=-T_a*math.log(-((V_t-E_a)/R-I_mx)/((I_mn)-(V_t-E_a)/R))\n",

-      "R=Rm\n",

-      "T_a=L/R\n",

-      "T_off=-T_a*math.log(-((-E_a)/R-I_mn)/((I_mx)-(-E_a)/R))\n",

-      "T=T_on+T_off\n",

-      "f=1/T    \n",

-      "a=T_on/T \n",

-      "\n",

-      "#Results\n",

-      "print(\"chopping freq=%.1f Hz\" %f)  \n",

-      "print(\"duty cycle ratio=%.3f\" %a)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "chopping freq=40.5 Hz\n",

-        "\n",

-        "duty cycle ratio=0.588\n"

-       ]

-      }

-     ],

-     "prompt_number": 30

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.29, Page No 445"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variablesI_mx=425\n",

-      "I_lt=180.0     #lower limit of current pulsation\n",

-      "I_mn=I_mx-I_lt\n",

-      "T_on=0.014\n",

-      "T_off=0.011\n",

-      "\n",

-      "#Calculations\n",

-      "T=T_on+T_off\n",

-      "T_a=.0635\n",

-      "a=T_on/T\n",

-      "V=(I_mx-I_mn*math.exp(-T_on/T_a))/(1-math.exp(-T_on/T_a))\n",

-      "a=.5\n",

-      "I_mn=(I_mx-V*(1-math.exp(-T_on/T_a)))/(math.exp(-T_on/T_a))\n",

-      "T=I_mx-I_mn    \n",

-      "T=T_on/a\n",

-      "f=1/T    \n",

-      "\n",

-      "#Results\n",

-      "print(\"higher limit of current pulsation=%.0f A\" %T)\n",

-      "print(\"chopping freq=%.3f Hz\" %f)\n",

-      "print(\"duty cycle ratio=%.2f\" %a)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "higher limit of current pulsation=0 A\n",

-        "chopping freq=35.714 Hz\n",

-        "duty cycle ratio=0.50\n"

-       ]

-      }

-     ],

-     "prompt_number": 32

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Power_Electronics/Chapter7_2.ipynb b/_Power_Electronics/Chapter7_2.ipynb
deleted file mode 100755
index 726160c8..00000000
--- a/_Power_Electronics/Chapter7_2.ipynb
+++ /dev/null
@@ -1,1036 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 07 : Choppers"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.2, Page No 387"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "a=0.4     #duty cycle %a=T_on/T\n",

-      "V_s=230.0\n",

-      "R=10.0\n",

-      "\n",

-      "#Calculations\n",

-      "V=a*(V_s-2)    \n",

-      "V_or=math.sqrt(a*(V_s-2)**2)    \n",

-      "P_o=V_or**2/R\n",

-      "P_i=V_s*V/R\n",

-      "n=P_o*100/P_i    \n",

-      "\n",

-      "#Results\n",

-      "print(\"avg o/p voltage=%.1f V\" %V)\n",

-      "print(\"rms value of o/p voltage=%.1f V\" %V_or)\n",

-      "print(\"chopper efficiency in percentage=%.2f\" %n)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "avg o/p voltage=91.2 V\n",

-        "rms value of o/p voltage=144.2 V\n",

-        "chopper efficiency in percentage=99.13\n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.3, Page No 388"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_i=220.0\n",

-      "V_o=660.0\n",

-      "\n",

-      "#Calculations\n",

-      "a=1-V_i/V_o\n",

-      "T_on=100.0     #microsecond\n",

-      "T=T_on/a\n",

-      "T_off=T-T_on    \n",

-      "T_off=T_off/2\n",

-      "T_on=T-T_off\n",

-      "a=T_on/T\n",

-      "V_o=V_i/(1-a)\n",

-      "\n",

-      "#Results    \n",

-      "print(\"pulse width of o/p voltage=%.0f us\" %T_off)\n",

-      "print(\"\\nnew o/p voltage=%.0f V\" %V_o)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "pulse width of o/p voltage=25 us\n",

-        "\n",

-        "new o/p voltage=1320 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 2

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.4 Page No 288"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "I_1=12.0\n",

-      "I_2=16.0\n",

-      "\n",

-      "#Calculations\n",

-      "I_0=(I_1+I_2)/2\n",

-      "R=10.0\n",

-      "V_0=I_0*R\n",

-      "V_s=200.0\n",

-      "a=V_0/V_s\n",

-      "r=a/(1-a)\n",

-      "\n",

-      "#Results\n",

-      "print(\"time ratio(T_on/T_off)=%.3f\" %r)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "time ratio(T_on/T_off)=2.333\n"

-       ]

-      }

-     ],

-     "prompt_number": 3

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.5, Page No 390"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_o=660.0\n",

-      "V_s=220.0\n",

-      "\n",

-      "#Calculations\n",

-      "a=(V_o/V_s)/(1+(V_o/V_s))\n",

-      "T_on=120\n",

-      "T=T_on/a\n",

-      "T_off=T-T_on \n",

-      "T_off=3*T_off\n",

-      "T_on=T-T_off\n",

-      "a=T_on/(T_on+T_off)\n",

-      "V_o=V_s*(a/(1-a))   \n",

-      "\n",

-      "#Results\n",

-      "print(\"pulse width o/p voltage=%.0f us\" %T_off)\n",

-      "print(\"\\nnew o/p voltage=%.2f V\" %V_o)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "pulse width o/p voltage=120 us\n",

-        "\n",

-        "new o/p voltage=73.33 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 4

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.11 Page No 408"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "R=1.0\n",

-      "L=.005\n",

-      "T_a=L/R\n",

-      "T=2000*10**-6\n",

-      "E=24.0\n",

-      "V_s=220\n",

-      "T_on=600*10**-6\n",

-      "a=T_on/T\n",

-      "\n",

-      "#Calculations\n",

-      "a1=(T_a/T)*math.log(1+(E/V_s)*((math.exp(T/T_a))-1))\n",

-      "if a1<a :\n",

-      "    print(\"load current in continuous\")\n",

-      "else:\n",

-      "    print(\"load current in discont.\")\n",

-      "\n",

-      "I_o=(a*V_s-E)/R    \n",

-      "I_mx=(V_s/R)*((1-math.exp(-T_on/T_a))/(1-math.exp(-T/T_a)))-E/R    \n",

-      "I_mn=(V_s/R)*((math.exp(T_on/T_a)-1)/(math.exp(T/T_a)-1))-E/R    \n",

-      "f=1/T\n",

-      "w=2*math.pi*f\n",

-      "I1=(2*V_s/(math.sqrt(2)*math.pi)*math.sin(math.radians(180*a)))/(math.sqrt(R**2+(w*L)**2))    \n",

-      "I2=(2*V_s/(2*math.sqrt(2)*math.pi)*math.sin(math.radians(2*180*a)))/(math.sqrt(R**2+(w*L*2)**2))    \n",

-      "I3=(2*V_s/(3*math.sqrt(2)*math.pi)*math.sin(math.radians(3*180*a)))/(math.sqrt(R**2+(w*L*3)**2))    \n",

-      "I_TAV=a*(V_s-E)/R-L*(I_mx-I_mn)/(R*T)   \n",

-      "P1=I_TAV*V_s\n",

-      "P2=E*I_o\n",

-      "I_or=math.sqrt(I_o**2+I1**2+I2**2+I3**2)\n",

-      "\n",

-      "#Results\n",

-      "print(\"avg o/p current=%.2f A\" %I_o)\n",

-      "print(\"max value of steady current=%.2f A\" %I_mx)\n",

-      "print(\"min value of steady current=%.2f A\" %I_mn)\n",

-      "print(\"first harmonic current=%.4f A\" %I1)\n",

-      "print(\"second harmonic current=%.4f A\" %I2)\n",

-      "print(\"third harmonic current=%.5f A\" %I3)\n",

-      "print(\"avg supply current=%.4f A\" %I_TAV)\n",

-      "print(\"i/p power=%.2f W\" %P1)\n",

-      "print(\"power absorbed by load emf=%.0f W\" %P2)\n",

-      "print(\"power loss in resistor=%.2f W\" %(P1-P2))\n",

-      "print(\"rms value of load current=%.3f A\" %I_or)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "load current in continuous\n",

-        "avg o/p current=42.00 A\n",

-        "max value of steady current=51.46 A\n",

-        "min value of steady current=33.03 A\n",

-        "first harmonic current=5.0903 A\n",

-        "second harmonic current=1.4983 A\n",

-        "third harmonic current=0.21643 A\n",

-        "avg supply current=12.7289 A\n",

-        "i/p power=2800.35 W\n",

-        "power absorbed by load emf=1008 W\n",

-        "power loss in resistor=1792.35 W\n",

-        "rms value of load current=42.334 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 7

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.12 Page No 411"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "R=1\n",

-      "L=.001\n",

-      "V_s=220\n",

-      "E=72.0\n",

-      "f=500.0\n",

-      "T_on=800*10**-6\n",

-      "T_a=L/R\n",

-      "T=1.0/f\n",

-      "m=E/V_s\n",

-      "a=T_on/T\n",

-      "\n",

-      "#Calculations\n",

-      "a1=(T_a/T)*math.log(1+m*(math.exp(-T/T_a)-1))\n",

-      "if a1>a :\n",

-      "    print(\"load current is continuous\")\n",

-      "else:\n",

-      "    print(\"load current is discontinuous\")\n",

-      "\n",

-      "t_x=T_on+L*math.log(1+((V_s-E)/272)*(1-math.exp(-T_on/T_a)))\n",

-      " #Value of t_x wrongly calculated in the book so ans of V_o and I_o varies\n",

-      "V_o=a*V_s+(1-t_x/T)*E    \n",

-      "I_o=(V_o-E)/R    \n",

-      "I_mx=(V_s-E)/R*(1-math.exp(-T_on/T_a)) \n",

-      "\n",

-      "#Results  \n",

-      "print(\"avg o/p voltage=%.2f V\" %V_o)\n",

-      "print(\"avg o/p current=%.2f A\" %I_o) \n",

-      "print(\"max value of load current=%.1f A\" %I_mx)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "load current is discontinuous\n",

-        "avg o/p voltage=121.77 V\n",

-        "avg o/p current=49.77 A\n",

-        "max value of load current=81.5 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 10

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.13, Page No 412"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "a=0.2\n",

-      "V_s=500\n",

-      "E=a*V_s\n",

-      "L=0.06\n",

-      "I=10\n",

-      "\n",

-      "#Calculations\n",

-      "T_on=(L*I)/(V_s-E)\n",

-      "f=a/T_on    \n",

-      "\n",

-      "#Results\n",

-      "print(\"chopping freq=%.2f Hz\" %f)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "chopping freq=133.33 Hz\n"

-       ]

-      }

-     ],

-     "prompt_number": 11

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.14 Page No 412"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "a=0.5\n",

-      "pu=0.1 #pu ripple\n",

-      "\n",

-      "#Calculations\n",

-      " #x=T/T_a\n",

-      " #y=exp(-a*x)\n",

-      "y=(1-pu)/(1+pu)\n",

-      " #after solving\n",

-      "x=math.log(1/y)/a\n",

-      "f=1000\n",

-      "T=1/f\n",

-      "T_a=T/x\n",

-      "R=2\n",

-      "L=R*T_a\n",

-      "Li=0.002\n",

-      "Le=L-Li    \n",

-      "\n",

-      "#Results\n",

-      "print(\"external inductance=%.3f mH\" %(Le*1000))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "external inductance=-2.000 mH\n"

-       ]

-      }

-     ],

-     "prompt_number": 12

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.15 Page No 414"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "R=10.0\n",

-      "L=0.015\n",

-      "T_a=L/R\n",

-      "f=1250.0\n",

-      "T=1.0/f\n",

-      "a=0.5\n",

-      "T_on=a*T\n",

-      "V_s=220.0\n",

-      "\n",

-      "#Calculations\n",

-      "I_mx=(V_s/R)*((1-math.exp(-T_on/T_a))/(1-math.exp(-T/T_a)))   \n",

-      "I_mn=(V_s/R)*((math.exp(T_on/T_a)-1)/(math.exp(T/T_a)-1))    \n",

-      "dI=I_mx-I_mn    \n",

-      "V_o=a*V_s\n",

-      "I_o=V_o/R    \n",

-      "I_or=math.sqrt(I_mx**2+dI**2/3+I_mx*dI)    \n",

-      "I_chr=math.sqrt(a)*I_or \n",

-      "\n",

-      "#Results\n",

-      "print(\"Max value of ripple current=%.2f A\" %dI)\n",

-      "print(\"Max value of load current=%.3f A\" %I_mx)\n",

-      "print(\"Min value of load current=%.2f A\" %I_mn)\n",

-      "print(\"Avg value of load current=%.2f A\" %I_o)   \n",

-      "print(\"rms value of load current=%.2f A\" %I_or)\n",

-      "print(\"rms value of chopper current=%.2f A\" %I_chr)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Max value of ripple current=2.92 A\n",

-        "Max value of load current=12.458 A\n",

-        "Min value of load current=9.54 A\n",

-        "Avg value of load current=11.00 A\n",

-        "rms value of load current=13.94 A\n",

-        "rms value of chopper current=9.86 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 14

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.17 Page No 417"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "L=0.0016\n",

-      "C=4*10**-6\n",

-      "\n",

-      "#Calculations\n",

-      "w=1/math.sqrt(L*C)\n",

-      "t=math.pi/w    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"time for which current flows=%.2f us\" %(t*10**6))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "time for which current flows=251.33 us\n"

-       ]

-      }

-     ],

-     "prompt_number": 15

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.18, Page No 424"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "t_q=20.0*10**-6\n",

-      "dt=20.0*10**-6\n",

-      "\n",

-      "#Calculations\n",

-      "t_c=t_q+dt\n",

-      "I_0=60.0\n",

-      "V_s=60.0\n",

-      "C=t_c*I_0/V_s \n",

-      "\n",

-      "#Results   \n",

-      "print(\"value of commutating capacitor=%.0f uF\" %(C*10**6))\n",

-      "\n",

-      "L1=(V_s/I_0)**2*C\n",

-      "L2=(2*t_c/math.pi)**2/C\n",

-      "if L1>L2 :\n",

-      "    print(\"value of commutating inductor=%.0f uH\" %(L1*10**6))\n",

-      "else:\n",

-      "    print(\"value of commutating inductor=%.0f uH\" %(L2*10**6))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "value of commutating capacitor=40 uF\n",

-        "value of commutating inductor=40 uH\n"

-       ]

-      }

-     ],

-     "prompt_number": 19

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.19, Page No 424"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "t=100.0*10**-6\n",

-      "R=10.0\n",

-      "\n",

-      "#Calculations\n",

-      " #V_s*(1-2*math.exp(-t/(R*C)))=0\n",

-      "C=-t/(R*math.log(1.0/2))    \n",

-      "L=(4/9.0)*C*R**2    \n",

-      "L=(1.0/4)*C*R**2    \n",

-      "\n",

-      "#Results\n",

-      "print(\"Value of comutating component C=%.3f uF\" %(C*10**6))\n",

-      "print(\"max permissible current through SCR is 2.5 times load current\")\n",

-      "print(\"value of comutating component L=%.1f uH\" %(L*10**6))\n",

-      "print(\"max permissible current through SCR is 1.5 times peak diode current\")\n",

-      "print(\"value of comutating component L=%.2f uH\" %(L*10**6))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Value of comutating component C=14.427 uF\n",

-        "max permissible current through SCR is 2.5 times load current\n",

-        "value of comutating component L=360.7 uH\n",

-        "max permissible current through SCR is 1.5 times peak diode current\n",

-        "value of comutating component L=360.67 uH\n"

-       ]

-      }

-     ],

-     "prompt_number": 20

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.20, Page No 426"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "T_on=800.0*10**-6\n",

-      "V_s=220.0\n",

-      "I_o=80.0\n",

-      "C=50*10**-6\n",

-      "\n",

-      "#Calculations\n",

-      "T=T_on+2*V_s*C/I_o    \n",

-      "L=20*10**-6\n",

-      "C=50*10**-6\n",

-      "i_T1=I_o+V_s*math.sqrt(C/L)    \n",

-      "i_TA=I_o    \n",

-      "t_c=C*V_s/I_o    \n",

-      "t_c1=(math.pi/2)*math.sqrt(L*C)    \n",

-      "t=150*10**-6\n",

-      "v_c=I_o*t/C-V_s  \n",

-      "\n",

-      "#Results  \n",

-      "print(\"effective on period=%.0f us\" %(T*10**6))\n",

-      "print(\"peak current through main thyristor=%.2f A\" %i_T1)\n",

-      "print(\"peak current through auxillery thyristor=%.0f A\" %i_TA)\n",

-      "print(\"turn off time for main thyristor=%.1f us\" %(t_c*10**6))\n",

-      "print(\"turn off time for auxillery thyristor=%.3f us\" %(t_c1*10**6))\n",

-      "print(\"total commutation interval=%.0f us\" %(2*t_c*10**6))\n",

-      "print(\"capacitor voltage=%.0f V\" %v_c)\n",

-      "print(\"time nedded to recharge the capacitor=%.0f us\" %(2*V_s*C/I_o*10**6))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for firing angle = 30deg\n",

-        "avg output voltage=232.509 V\n",

-        "for firing angle = 60deg\n",

-        "avg output voltage=133.65 V\n",

-        "avg current rating=12 A\n",

-        "rms current rating=20.785 A\n",

-        "PIV of SCR=565.7 V\n",

-        "power dissipated=16.8 W\n"

-       ]

-      }

-     ],

-     "prompt_number": 122

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.21, Page No 427"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "I_o=260.0\n",

-      "V_s=220.0\n",

-      "fos=2 #factor of safety\n",

-      "\n",

-      "#Calculations\n",

-      "t_off=18*10**-6\n",

-      "t_c=2*t_off\n",

-      "C=t_c*I_o/V_s    \n",

-      "L=(V_s/(0.8*I_o))**2*C    \n",

-      "f=400\n",

-      "a_mn=math.pi*f*math.sqrt(L*C)\n",

-      "V_omn=V_s*(a_mn+2*f*t_c)    \n",

-      "V_omx=V_s    \n",

-      "\n",

-      "#Results\n",

-      "print(\"Value of C=%.3f uF\" %(C*10**6))\n",

-      "print(\"value of L=%.3f uH\" %(L*10**6))\n",

-      "print(\"min value of o/p voltage=%.3f V\" %V_omn)\n",

-      "print(\"max value of o/p voltage=%.0f V\" %V_omx)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "firing angle delay=47.461 deg\n",

-        "pf=0.646\n",

-        "firing angle delay=127.71 deg\n"

-       ]

-      }

-     ],

-     "prompt_number": "*"

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.22, Page No 434"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "x=2.0\n",

-      "t_q=30*10**-6\n",

-      "dt=30*10**-6\n",

-      "t_c=t_q+dt\n",

-      "V_s=230.0\n",

-      "I_o=200.0\n",

-      "\n",

-      "#Calculations\n",

-      "L=V_s*t_c/(x*I_o*(math.pi-2*math.asin(1/x)))    \n",

-      "C=x*I_o*t_c/(V_s*(math.pi-2*math.asin(1/x)))    \n",

-      "V_cp=V_s+I_o*math.sqrt(L/C)    \n",

-      "I_cp=x*I_o    \n",

-      "x=3\n",

-      "L=V_s*t_c/(x*I_o*(math.pi-2*math.asin(1/x)))   \n",

-      "C=x*I_o*t_c/(V_s*(math.pi-2*math.asin(1/x)))    \n",

-      "V_cp=V_s+I_o*math.sqrt(L/C)    \n",

-      "I_cp=x*I_o    \n",

-      "\n",

-      "#Results\n",

-      "print(\"value of commutating inductor=%.3f uH\" %(L*10**6))\n",

-      "print(\"value of commutating capacitor=%.3f uF\" %(C*10**6))\n",

-      "print(\"peak capacitor voltage=%.0f V\" %V_cp)\n",

-      "print(\"peak commutataing current=%.0f A\" %I_cp)\n",

-      "print(\"value of commutating inductor=%.3f uH\" %(L*10**6))\n",

-      "print(\"value of commutating capacitor=%.3f uF\" %(C*10**6))\n",

-      "print(\"peak capacitor voltage=%.2f V\" %V_cp)\n",

-      "print(\"peak commutataing current=%.0f A\" %I_cp)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "value of commutating inductor=7.321 uH\n",

-        "value of commutating capacitor=49.822 uF\n",

-        "peak capacitor voltage=307 V\n",

-        "peak commutataing current=600 A\n",

-        "value of commutating inductor=7.321 uH\n",

-        "value of commutating capacitor=49.822 uF\n",

-        "peak capacitor voltage=306.67 V\n",

-        "peak commutataing current=600 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 25

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.23, Page No 434"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variablesV_s=230\n",

-      "C=50*10**-6\n",

-      "L=20*10**-6\n",

-      "I_cp=V_s*math.sqrt(C/L)\n",

-      "I_o=200\n",

-      "x=I_cp/I_o\n",

-      "\n",

-      "#Calculations\n",

-      "t_c=(math.pi-2*math.asin(1/x))*math.sqrt(C*L)   \n",

-      "th1=math.degrees(math.asin(1.0/x))\n",

-      "t=(5*math.pi/2-th1*math.pi/180)*math.sqrt(L*C)+C*V_s*(1-math.cos(math.radians(th1)))/I_o    \n",

-      "t=(math.pi-th1*math.pi/180)*math.sqrt(L*C)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"turn off time of main thyristor=%.2f us\" %(t_c*10**6))\n",

-      "print(\"total commutation interval=%.3f us\" %(t*10**6))\n",

-      "print(\"turn off time of auxillery thyristor=%.3f us\" %(t*10**6))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "turn off time of main thyristor=62.52 us\n",

-        "total commutation interval=80.931 us\n",

-        "turn off time of auxillery thyristor=80.931 us\n"

-       ]

-      }

-     ],

-     "prompt_number": 27

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.24, Page No 440"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "tc=0.006\n",

-      "R=10.0\n",

-      "L=R*tc\n",

-      "f=2000.0\n",

-      "\n",

-      "#Calculations\n",

-      "T=1/f\n",

-      "V_o=50.0\n",

-      "V_s=100.0\n",

-      "a=V_o/V_s\n",

-      "T_on=a*T\n",

-      "T_off=T-T_on\n",

-      "dI=V_o*T_off/L\n",

-      "I_o=V_o/R\n",

-      "I2=I_o+dI/2    \n",

-      "I1=I_o-dI/2    \n",

-      "\n",

-      "#Results\n",

-      "print(\"max value of load current=%.3f A\" %I2)\n",

-      "print(\"min value of load current=%.3f A\" %I1)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "max value of load current=5.104 A\n",

-        "min value of load current=4.896 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 28

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.27, Page No 443"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "I_a=30.0\n",

-      "r_a=.5\n",

-      "V_s=220.0\n",

-      "\n",

-      "#Calculations\n",

-      "a=I_a*r_a/V_s    \n",

-      "a=1\n",

-      "k=.1 #V/rpm\n",

-      "N=(a*V_s-I_a*r_a)/k    \n",

-      "\n",

-      "#Results\n",

-      "print(\"min value of duty cycle=%.3f\" %a)\n",

-      "print(\"min Value of speed control=%.0f rpm\" %0)\n",

-      "print(\"max value of duty cycle=%.0f\" %a)\n",

-      "print(\"max value of speed control=%.0f rpm\" %N)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "min value of duty cycle=1.000\n",

-        "min Value of speed control=0 rpm\n",

-        "max value of duty cycle=1\n",

-        "max value of speed control=2050 rpm\n"

-       ]

-      }

-     ],

-     "prompt_number": 29

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.28, Page No 444"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_t=72.0\n",

-      "I_a=200.0\n",

-      "r_a=0.045\n",

-      "N=2500.0\n",

-      "\n",

-      "#Calculations\n",

-      "k=(V_t-I_a*r_a)/N\n",

-      "E_a=k*1000\n",

-      "L=.007\n",

-      "Rm=.045\n",

-      "Rb=0.065\n",

-      "R=Rm+Rb\n",

-      "T_a=L/R\n",

-      "I_mx=230\n",

-      "I_mn=180\n",

-      "T_on=-T_a*math.log(-((V_t-E_a)/R-I_mx)/((I_mn)-(V_t-E_a)/R))\n",

-      "R=Rm\n",

-      "T_a=L/R\n",

-      "T_off=-T_a*math.log(-((-E_a)/R-I_mn)/((I_mx)-(-E_a)/R))\n",

-      "T=T_on+T_off\n",

-      "f=1/T    \n",

-      "a=T_on/T \n",

-      "\n",

-      "#Results\n",

-      "print(\"chopping freq=%.1f Hz\" %f)  \n",

-      "print(\"duty cycle ratio=%.3f\" %a)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "chopping freq=40.5 Hz\n",

-        "\n",

-        "duty cycle ratio=0.588\n"

-       ]

-      }

-     ],

-     "prompt_number": 30

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.29, Page No 445"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variablesI_mx=425\n",

-      "I_lt=180.0     #lower limit of current pulsation\n",

-      "I_mn=I_mx-I_lt\n",

-      "T_on=0.014\n",

-      "T_off=0.011\n",

-      "\n",

-      "#Calculations\n",

-      "T=T_on+T_off\n",

-      "T_a=.0635\n",

-      "a=T_on/T\n",

-      "V=(I_mx-I_mn*math.exp(-T_on/T_a))/(1-math.exp(-T_on/T_a))\n",

-      "a=.5\n",

-      "I_mn=(I_mx-V*(1-math.exp(-T_on/T_a)))/(math.exp(-T_on/T_a))\n",

-      "T=I_mx-I_mn    \n",

-      "T=T_on/a\n",

-      "f=1/T    \n",

-      "\n",

-      "#Results\n",

-      "print(\"higher limit of current pulsation=%.0f A\" %T)\n",

-      "print(\"chopping freq=%.3f Hz\" %f)\n",

-      "print(\"duty cycle ratio=%.2f\" %a)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "higher limit of current pulsation=0 A\n",

-        "chopping freq=35.714 Hz\n",

-        "duty cycle ratio=0.50\n"

-       ]

-      }

-     ],

-     "prompt_number": 32

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Power_Electronics/Chapter7_3.ipynb b/_Power_Electronics/Chapter7_3.ipynb
deleted file mode 100755
index 726160c8..00000000
--- a/_Power_Electronics/Chapter7_3.ipynb
+++ /dev/null
@@ -1,1036 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 07 : Choppers"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.2, Page No 387"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "a=0.4     #duty cycle %a=T_on/T\n",

-      "V_s=230.0\n",

-      "R=10.0\n",

-      "\n",

-      "#Calculations\n",

-      "V=a*(V_s-2)    \n",

-      "V_or=math.sqrt(a*(V_s-2)**2)    \n",

-      "P_o=V_or**2/R\n",

-      "P_i=V_s*V/R\n",

-      "n=P_o*100/P_i    \n",

-      "\n",

-      "#Results\n",

-      "print(\"avg o/p voltage=%.1f V\" %V)\n",

-      "print(\"rms value of o/p voltage=%.1f V\" %V_or)\n",

-      "print(\"chopper efficiency in percentage=%.2f\" %n)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "avg o/p voltage=91.2 V\n",

-        "rms value of o/p voltage=144.2 V\n",

-        "chopper efficiency in percentage=99.13\n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.3, Page No 388"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_i=220.0\n",

-      "V_o=660.0\n",

-      "\n",

-      "#Calculations\n",

-      "a=1-V_i/V_o\n",

-      "T_on=100.0     #microsecond\n",

-      "T=T_on/a\n",

-      "T_off=T-T_on    \n",

-      "T_off=T_off/2\n",

-      "T_on=T-T_off\n",

-      "a=T_on/T\n",

-      "V_o=V_i/(1-a)\n",

-      "\n",

-      "#Results    \n",

-      "print(\"pulse width of o/p voltage=%.0f us\" %T_off)\n",

-      "print(\"\\nnew o/p voltage=%.0f V\" %V_o)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "pulse width of o/p voltage=25 us\n",

-        "\n",

-        "new o/p voltage=1320 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 2

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.4 Page No 288"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "I_1=12.0\n",

-      "I_2=16.0\n",

-      "\n",

-      "#Calculations\n",

-      "I_0=(I_1+I_2)/2\n",

-      "R=10.0\n",

-      "V_0=I_0*R\n",

-      "V_s=200.0\n",

-      "a=V_0/V_s\n",

-      "r=a/(1-a)\n",

-      "\n",

-      "#Results\n",

-      "print(\"time ratio(T_on/T_off)=%.3f\" %r)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "time ratio(T_on/T_off)=2.333\n"

-       ]

-      }

-     ],

-     "prompt_number": 3

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.5, Page No 390"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_o=660.0\n",

-      "V_s=220.0\n",

-      "\n",

-      "#Calculations\n",

-      "a=(V_o/V_s)/(1+(V_o/V_s))\n",

-      "T_on=120\n",

-      "T=T_on/a\n",

-      "T_off=T-T_on \n",

-      "T_off=3*T_off\n",

-      "T_on=T-T_off\n",

-      "a=T_on/(T_on+T_off)\n",

-      "V_o=V_s*(a/(1-a))   \n",

-      "\n",

-      "#Results\n",

-      "print(\"pulse width o/p voltage=%.0f us\" %T_off)\n",

-      "print(\"\\nnew o/p voltage=%.2f V\" %V_o)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "pulse width o/p voltage=120 us\n",

-        "\n",

-        "new o/p voltage=73.33 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 4

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.11 Page No 408"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "R=1.0\n",

-      "L=.005\n",

-      "T_a=L/R\n",

-      "T=2000*10**-6\n",

-      "E=24.0\n",

-      "V_s=220\n",

-      "T_on=600*10**-6\n",

-      "a=T_on/T\n",

-      "\n",

-      "#Calculations\n",

-      "a1=(T_a/T)*math.log(1+(E/V_s)*((math.exp(T/T_a))-1))\n",

-      "if a1<a :\n",

-      "    print(\"load current in continuous\")\n",

-      "else:\n",

-      "    print(\"load current in discont.\")\n",

-      "\n",

-      "I_o=(a*V_s-E)/R    \n",

-      "I_mx=(V_s/R)*((1-math.exp(-T_on/T_a))/(1-math.exp(-T/T_a)))-E/R    \n",

-      "I_mn=(V_s/R)*((math.exp(T_on/T_a)-1)/(math.exp(T/T_a)-1))-E/R    \n",

-      "f=1/T\n",

-      "w=2*math.pi*f\n",

-      "I1=(2*V_s/(math.sqrt(2)*math.pi)*math.sin(math.radians(180*a)))/(math.sqrt(R**2+(w*L)**2))    \n",

-      "I2=(2*V_s/(2*math.sqrt(2)*math.pi)*math.sin(math.radians(2*180*a)))/(math.sqrt(R**2+(w*L*2)**2))    \n",

-      "I3=(2*V_s/(3*math.sqrt(2)*math.pi)*math.sin(math.radians(3*180*a)))/(math.sqrt(R**2+(w*L*3)**2))    \n",

-      "I_TAV=a*(V_s-E)/R-L*(I_mx-I_mn)/(R*T)   \n",

-      "P1=I_TAV*V_s\n",

-      "P2=E*I_o\n",

-      "I_or=math.sqrt(I_o**2+I1**2+I2**2+I3**2)\n",

-      "\n",

-      "#Results\n",

-      "print(\"avg o/p current=%.2f A\" %I_o)\n",

-      "print(\"max value of steady current=%.2f A\" %I_mx)\n",

-      "print(\"min value of steady current=%.2f A\" %I_mn)\n",

-      "print(\"first harmonic current=%.4f A\" %I1)\n",

-      "print(\"second harmonic current=%.4f A\" %I2)\n",

-      "print(\"third harmonic current=%.5f A\" %I3)\n",

-      "print(\"avg supply current=%.4f A\" %I_TAV)\n",

-      "print(\"i/p power=%.2f W\" %P1)\n",

-      "print(\"power absorbed by load emf=%.0f W\" %P2)\n",

-      "print(\"power loss in resistor=%.2f W\" %(P1-P2))\n",

-      "print(\"rms value of load current=%.3f A\" %I_or)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "load current in continuous\n",

-        "avg o/p current=42.00 A\n",

-        "max value of steady current=51.46 A\n",

-        "min value of steady current=33.03 A\n",

-        "first harmonic current=5.0903 A\n",

-        "second harmonic current=1.4983 A\n",

-        "third harmonic current=0.21643 A\n",

-        "avg supply current=12.7289 A\n",

-        "i/p power=2800.35 W\n",

-        "power absorbed by load emf=1008 W\n",

-        "power loss in resistor=1792.35 W\n",

-        "rms value of load current=42.334 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 7

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.12 Page No 411"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "R=1\n",

-      "L=.001\n",

-      "V_s=220\n",

-      "E=72.0\n",

-      "f=500.0\n",

-      "T_on=800*10**-6\n",

-      "T_a=L/R\n",

-      "T=1.0/f\n",

-      "m=E/V_s\n",

-      "a=T_on/T\n",

-      "\n",

-      "#Calculations\n",

-      "a1=(T_a/T)*math.log(1+m*(math.exp(-T/T_a)-1))\n",

-      "if a1>a :\n",

-      "    print(\"load current is continuous\")\n",

-      "else:\n",

-      "    print(\"load current is discontinuous\")\n",

-      "\n",

-      "t_x=T_on+L*math.log(1+((V_s-E)/272)*(1-math.exp(-T_on/T_a)))\n",

-      " #Value of t_x wrongly calculated in the book so ans of V_o and I_o varies\n",

-      "V_o=a*V_s+(1-t_x/T)*E    \n",

-      "I_o=(V_o-E)/R    \n",

-      "I_mx=(V_s-E)/R*(1-math.exp(-T_on/T_a)) \n",

-      "\n",

-      "#Results  \n",

-      "print(\"avg o/p voltage=%.2f V\" %V_o)\n",

-      "print(\"avg o/p current=%.2f A\" %I_o) \n",

-      "print(\"max value of load current=%.1f A\" %I_mx)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "load current is discontinuous\n",

-        "avg o/p voltage=121.77 V\n",

-        "avg o/p current=49.77 A\n",

-        "max value of load current=81.5 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 10

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.13, Page No 412"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "a=0.2\n",

-      "V_s=500\n",

-      "E=a*V_s\n",

-      "L=0.06\n",

-      "I=10\n",

-      "\n",

-      "#Calculations\n",

-      "T_on=(L*I)/(V_s-E)\n",

-      "f=a/T_on    \n",

-      "\n",

-      "#Results\n",

-      "print(\"chopping freq=%.2f Hz\" %f)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "chopping freq=133.33 Hz\n"

-       ]

-      }

-     ],

-     "prompt_number": 11

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.14 Page No 412"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "a=0.5\n",

-      "pu=0.1 #pu ripple\n",

-      "\n",

-      "#Calculations\n",

-      " #x=T/T_a\n",

-      " #y=exp(-a*x)\n",

-      "y=(1-pu)/(1+pu)\n",

-      " #after solving\n",

-      "x=math.log(1/y)/a\n",

-      "f=1000\n",

-      "T=1/f\n",

-      "T_a=T/x\n",

-      "R=2\n",

-      "L=R*T_a\n",

-      "Li=0.002\n",

-      "Le=L-Li    \n",

-      "\n",

-      "#Results\n",

-      "print(\"external inductance=%.3f mH\" %(Le*1000))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "external inductance=-2.000 mH\n"

-       ]

-      }

-     ],

-     "prompt_number": 12

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.15 Page No 414"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "R=10.0\n",

-      "L=0.015\n",

-      "T_a=L/R\n",

-      "f=1250.0\n",

-      "T=1.0/f\n",

-      "a=0.5\n",

-      "T_on=a*T\n",

-      "V_s=220.0\n",

-      "\n",

-      "#Calculations\n",

-      "I_mx=(V_s/R)*((1-math.exp(-T_on/T_a))/(1-math.exp(-T/T_a)))   \n",

-      "I_mn=(V_s/R)*((math.exp(T_on/T_a)-1)/(math.exp(T/T_a)-1))    \n",

-      "dI=I_mx-I_mn    \n",

-      "V_o=a*V_s\n",

-      "I_o=V_o/R    \n",

-      "I_or=math.sqrt(I_mx**2+dI**2/3+I_mx*dI)    \n",

-      "I_chr=math.sqrt(a)*I_or \n",

-      "\n",

-      "#Results\n",

-      "print(\"Max value of ripple current=%.2f A\" %dI)\n",

-      "print(\"Max value of load current=%.3f A\" %I_mx)\n",

-      "print(\"Min value of load current=%.2f A\" %I_mn)\n",

-      "print(\"Avg value of load current=%.2f A\" %I_o)   \n",

-      "print(\"rms value of load current=%.2f A\" %I_or)\n",

-      "print(\"rms value of chopper current=%.2f A\" %I_chr)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Max value of ripple current=2.92 A\n",

-        "Max value of load current=12.458 A\n",

-        "Min value of load current=9.54 A\n",

-        "Avg value of load current=11.00 A\n",

-        "rms value of load current=13.94 A\n",

-        "rms value of chopper current=9.86 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 14

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.17 Page No 417"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "L=0.0016\n",

-      "C=4*10**-6\n",

-      "\n",

-      "#Calculations\n",

-      "w=1/math.sqrt(L*C)\n",

-      "t=math.pi/w    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"time for which current flows=%.2f us\" %(t*10**6))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "time for which current flows=251.33 us\n"

-       ]

-      }

-     ],

-     "prompt_number": 15

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.18, Page No 424"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "t_q=20.0*10**-6\n",

-      "dt=20.0*10**-6\n",

-      "\n",

-      "#Calculations\n",

-      "t_c=t_q+dt\n",

-      "I_0=60.0\n",

-      "V_s=60.0\n",

-      "C=t_c*I_0/V_s \n",

-      "\n",

-      "#Results   \n",

-      "print(\"value of commutating capacitor=%.0f uF\" %(C*10**6))\n",

-      "\n",

-      "L1=(V_s/I_0)**2*C\n",

-      "L2=(2*t_c/math.pi)**2/C\n",

-      "if L1>L2 :\n",

-      "    print(\"value of commutating inductor=%.0f uH\" %(L1*10**6))\n",

-      "else:\n",

-      "    print(\"value of commutating inductor=%.0f uH\" %(L2*10**6))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "value of commutating capacitor=40 uF\n",

-        "value of commutating inductor=40 uH\n"

-       ]

-      }

-     ],

-     "prompt_number": 19

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.19, Page No 424"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "t=100.0*10**-6\n",

-      "R=10.0\n",

-      "\n",

-      "#Calculations\n",

-      " #V_s*(1-2*math.exp(-t/(R*C)))=0\n",

-      "C=-t/(R*math.log(1.0/2))    \n",

-      "L=(4/9.0)*C*R**2    \n",

-      "L=(1.0/4)*C*R**2    \n",

-      "\n",

-      "#Results\n",

-      "print(\"Value of comutating component C=%.3f uF\" %(C*10**6))\n",

-      "print(\"max permissible current through SCR is 2.5 times load current\")\n",

-      "print(\"value of comutating component L=%.1f uH\" %(L*10**6))\n",

-      "print(\"max permissible current through SCR is 1.5 times peak diode current\")\n",

-      "print(\"value of comutating component L=%.2f uH\" %(L*10**6))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Value of comutating component C=14.427 uF\n",

-        "max permissible current through SCR is 2.5 times load current\n",

-        "value of comutating component L=360.7 uH\n",

-        "max permissible current through SCR is 1.5 times peak diode current\n",

-        "value of comutating component L=360.67 uH\n"

-       ]

-      }

-     ],

-     "prompt_number": 20

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.20, Page No 426"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "T_on=800.0*10**-6\n",

-      "V_s=220.0\n",

-      "I_o=80.0\n",

-      "C=50*10**-6\n",

-      "\n",

-      "#Calculations\n",

-      "T=T_on+2*V_s*C/I_o    \n",

-      "L=20*10**-6\n",

-      "C=50*10**-6\n",

-      "i_T1=I_o+V_s*math.sqrt(C/L)    \n",

-      "i_TA=I_o    \n",

-      "t_c=C*V_s/I_o    \n",

-      "t_c1=(math.pi/2)*math.sqrt(L*C)    \n",

-      "t=150*10**-6\n",

-      "v_c=I_o*t/C-V_s  \n",

-      "\n",

-      "#Results  \n",

-      "print(\"effective on period=%.0f us\" %(T*10**6))\n",

-      "print(\"peak current through main thyristor=%.2f A\" %i_T1)\n",

-      "print(\"peak current through auxillery thyristor=%.0f A\" %i_TA)\n",

-      "print(\"turn off time for main thyristor=%.1f us\" %(t_c*10**6))\n",

-      "print(\"turn off time for auxillery thyristor=%.3f us\" %(t_c1*10**6))\n",

-      "print(\"total commutation interval=%.0f us\" %(2*t_c*10**6))\n",

-      "print(\"capacitor voltage=%.0f V\" %v_c)\n",

-      "print(\"time nedded to recharge the capacitor=%.0f us\" %(2*V_s*C/I_o*10**6))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for firing angle = 30deg\n",

-        "avg output voltage=232.509 V\n",

-        "for firing angle = 60deg\n",

-        "avg output voltage=133.65 V\n",

-        "avg current rating=12 A\n",

-        "rms current rating=20.785 A\n",

-        "PIV of SCR=565.7 V\n",

-        "power dissipated=16.8 W\n"

-       ]

-      }

-     ],

-     "prompt_number": 122

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.21, Page No 427"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "I_o=260.0\n",

-      "V_s=220.0\n",

-      "fos=2 #factor of safety\n",

-      "\n",

-      "#Calculations\n",

-      "t_off=18*10**-6\n",

-      "t_c=2*t_off\n",

-      "C=t_c*I_o/V_s    \n",

-      "L=(V_s/(0.8*I_o))**2*C    \n",

-      "f=400\n",

-      "a_mn=math.pi*f*math.sqrt(L*C)\n",

-      "V_omn=V_s*(a_mn+2*f*t_c)    \n",

-      "V_omx=V_s    \n",

-      "\n",

-      "#Results\n",

-      "print(\"Value of C=%.3f uF\" %(C*10**6))\n",

-      "print(\"value of L=%.3f uH\" %(L*10**6))\n",

-      "print(\"min value of o/p voltage=%.3f V\" %V_omn)\n",

-      "print(\"max value of o/p voltage=%.0f V\" %V_omx)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "firing angle delay=47.461 deg\n",

-        "pf=0.646\n",

-        "firing angle delay=127.71 deg\n"

-       ]

-      }

-     ],

-     "prompt_number": "*"

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.22, Page No 434"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "x=2.0\n",

-      "t_q=30*10**-6\n",

-      "dt=30*10**-6\n",

-      "t_c=t_q+dt\n",

-      "V_s=230.0\n",

-      "I_o=200.0\n",

-      "\n",

-      "#Calculations\n",

-      "L=V_s*t_c/(x*I_o*(math.pi-2*math.asin(1/x)))    \n",

-      "C=x*I_o*t_c/(V_s*(math.pi-2*math.asin(1/x)))    \n",

-      "V_cp=V_s+I_o*math.sqrt(L/C)    \n",

-      "I_cp=x*I_o    \n",

-      "x=3\n",

-      "L=V_s*t_c/(x*I_o*(math.pi-2*math.asin(1/x)))   \n",

-      "C=x*I_o*t_c/(V_s*(math.pi-2*math.asin(1/x)))    \n",

-      "V_cp=V_s+I_o*math.sqrt(L/C)    \n",

-      "I_cp=x*I_o    \n",

-      "\n",

-      "#Results\n",

-      "print(\"value of commutating inductor=%.3f uH\" %(L*10**6))\n",

-      "print(\"value of commutating capacitor=%.3f uF\" %(C*10**6))\n",

-      "print(\"peak capacitor voltage=%.0f V\" %V_cp)\n",

-      "print(\"peak commutataing current=%.0f A\" %I_cp)\n",

-      "print(\"value of commutating inductor=%.3f uH\" %(L*10**6))\n",

-      "print(\"value of commutating capacitor=%.3f uF\" %(C*10**6))\n",

-      "print(\"peak capacitor voltage=%.2f V\" %V_cp)\n",

-      "print(\"peak commutataing current=%.0f A\" %I_cp)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "value of commutating inductor=7.321 uH\n",

-        "value of commutating capacitor=49.822 uF\n",

-        "peak capacitor voltage=307 V\n",

-        "peak commutataing current=600 A\n",

-        "value of commutating inductor=7.321 uH\n",

-        "value of commutating capacitor=49.822 uF\n",

-        "peak capacitor voltage=306.67 V\n",

-        "peak commutataing current=600 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 25

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.23, Page No 434"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variablesV_s=230\n",

-      "C=50*10**-6\n",

-      "L=20*10**-6\n",

-      "I_cp=V_s*math.sqrt(C/L)\n",

-      "I_o=200\n",

-      "x=I_cp/I_o\n",

-      "\n",

-      "#Calculations\n",

-      "t_c=(math.pi-2*math.asin(1/x))*math.sqrt(C*L)   \n",

-      "th1=math.degrees(math.asin(1.0/x))\n",

-      "t=(5*math.pi/2-th1*math.pi/180)*math.sqrt(L*C)+C*V_s*(1-math.cos(math.radians(th1)))/I_o    \n",

-      "t=(math.pi-th1*math.pi/180)*math.sqrt(L*C)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"turn off time of main thyristor=%.2f us\" %(t_c*10**6))\n",

-      "print(\"total commutation interval=%.3f us\" %(t*10**6))\n",

-      "print(\"turn off time of auxillery thyristor=%.3f us\" %(t*10**6))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "turn off time of main thyristor=62.52 us\n",

-        "total commutation interval=80.931 us\n",

-        "turn off time of auxillery thyristor=80.931 us\n"

-       ]

-      }

-     ],

-     "prompt_number": 27

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.24, Page No 440"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "tc=0.006\n",

-      "R=10.0\n",

-      "L=R*tc\n",

-      "f=2000.0\n",

-      "\n",

-      "#Calculations\n",

-      "T=1/f\n",

-      "V_o=50.0\n",

-      "V_s=100.0\n",

-      "a=V_o/V_s\n",

-      "T_on=a*T\n",

-      "T_off=T-T_on\n",

-      "dI=V_o*T_off/L\n",

-      "I_o=V_o/R\n",

-      "I2=I_o+dI/2    \n",

-      "I1=I_o-dI/2    \n",

-      "\n",

-      "#Results\n",

-      "print(\"max value of load current=%.3f A\" %I2)\n",

-      "print(\"min value of load current=%.3f A\" %I1)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "max value of load current=5.104 A\n",

-        "min value of load current=4.896 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 28

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.27, Page No 443"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "I_a=30.0\n",

-      "r_a=.5\n",

-      "V_s=220.0\n",

-      "\n",

-      "#Calculations\n",

-      "a=I_a*r_a/V_s    \n",

-      "a=1\n",

-      "k=.1 #V/rpm\n",

-      "N=(a*V_s-I_a*r_a)/k    \n",

-      "\n",

-      "#Results\n",

-      "print(\"min value of duty cycle=%.3f\" %a)\n",

-      "print(\"min Value of speed control=%.0f rpm\" %0)\n",

-      "print(\"max value of duty cycle=%.0f\" %a)\n",

-      "print(\"max value of speed control=%.0f rpm\" %N)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "min value of duty cycle=1.000\n",

-        "min Value of speed control=0 rpm\n",

-        "max value of duty cycle=1\n",

-        "max value of speed control=2050 rpm\n"

-       ]

-      }

-     ],

-     "prompt_number": 29

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.28, Page No 444"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_t=72.0\n",

-      "I_a=200.0\n",

-      "r_a=0.045\n",

-      "N=2500.0\n",

-      "\n",

-      "#Calculations\n",

-      "k=(V_t-I_a*r_a)/N\n",

-      "E_a=k*1000\n",

-      "L=.007\n",

-      "Rm=.045\n",

-      "Rb=0.065\n",

-      "R=Rm+Rb\n",

-      "T_a=L/R\n",

-      "I_mx=230\n",

-      "I_mn=180\n",

-      "T_on=-T_a*math.log(-((V_t-E_a)/R-I_mx)/((I_mn)-(V_t-E_a)/R))\n",

-      "R=Rm\n",

-      "T_a=L/R\n",

-      "T_off=-T_a*math.log(-((-E_a)/R-I_mn)/((I_mx)-(-E_a)/R))\n",

-      "T=T_on+T_off\n",

-      "f=1/T    \n",

-      "a=T_on/T \n",

-      "\n",

-      "#Results\n",

-      "print(\"chopping freq=%.1f Hz\" %f)  \n",

-      "print(\"duty cycle ratio=%.3f\" %a)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "chopping freq=40.5 Hz\n",

-        "\n",

-        "duty cycle ratio=0.588\n"

-       ]

-      }

-     ],

-     "prompt_number": 30

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.29, Page No 445"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variablesI_mx=425\n",

-      "I_lt=180.0     #lower limit of current pulsation\n",

-      "I_mn=I_mx-I_lt\n",

-      "T_on=0.014\n",

-      "T_off=0.011\n",

-      "\n",

-      "#Calculations\n",

-      "T=T_on+T_off\n",

-      "T_a=.0635\n",

-      "a=T_on/T\n",

-      "V=(I_mx-I_mn*math.exp(-T_on/T_a))/(1-math.exp(-T_on/T_a))\n",

-      "a=.5\n",

-      "I_mn=(I_mx-V*(1-math.exp(-T_on/T_a)))/(math.exp(-T_on/T_a))\n",

-      "T=I_mx-I_mn    \n",

-      "T=T_on/a\n",

-      "f=1/T    \n",

-      "\n",

-      "#Results\n",

-      "print(\"higher limit of current pulsation=%.0f A\" %T)\n",

-      "print(\"chopping freq=%.3f Hz\" %f)\n",

-      "print(\"duty cycle ratio=%.2f\" %a)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "higher limit of current pulsation=0 A\n",

-        "chopping freq=35.714 Hz\n",

-        "duty cycle ratio=0.50\n"

-       ]

-      }

-     ],

-     "prompt_number": 32

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Power_Electronics/Chapter7_4.ipynb b/_Power_Electronics/Chapter7_4.ipynb
deleted file mode 100755
index 726160c8..00000000
--- a/_Power_Electronics/Chapter7_4.ipynb
+++ /dev/null
@@ -1,1036 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 07 : Choppers"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.2, Page No 387"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "a=0.4     #duty cycle %a=T_on/T\n",

-      "V_s=230.0\n",

-      "R=10.0\n",

-      "\n",

-      "#Calculations\n",

-      "V=a*(V_s-2)    \n",

-      "V_or=math.sqrt(a*(V_s-2)**2)    \n",

-      "P_o=V_or**2/R\n",

-      "P_i=V_s*V/R\n",

-      "n=P_o*100/P_i    \n",

-      "\n",

-      "#Results\n",

-      "print(\"avg o/p voltage=%.1f V\" %V)\n",

-      "print(\"rms value of o/p voltage=%.1f V\" %V_or)\n",

-      "print(\"chopper efficiency in percentage=%.2f\" %n)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "avg o/p voltage=91.2 V\n",

-        "rms value of o/p voltage=144.2 V\n",

-        "chopper efficiency in percentage=99.13\n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.3, Page No 388"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_i=220.0\n",

-      "V_o=660.0\n",

-      "\n",

-      "#Calculations\n",

-      "a=1-V_i/V_o\n",

-      "T_on=100.0     #microsecond\n",

-      "T=T_on/a\n",

-      "T_off=T-T_on    \n",

-      "T_off=T_off/2\n",

-      "T_on=T-T_off\n",

-      "a=T_on/T\n",

-      "V_o=V_i/(1-a)\n",

-      "\n",

-      "#Results    \n",

-      "print(\"pulse width of o/p voltage=%.0f us\" %T_off)\n",

-      "print(\"\\nnew o/p voltage=%.0f V\" %V_o)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "pulse width of o/p voltage=25 us\n",

-        "\n",

-        "new o/p voltage=1320 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 2

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.4 Page No 288"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "I_1=12.0\n",

-      "I_2=16.0\n",

-      "\n",

-      "#Calculations\n",

-      "I_0=(I_1+I_2)/2\n",

-      "R=10.0\n",

-      "V_0=I_0*R\n",

-      "V_s=200.0\n",

-      "a=V_0/V_s\n",

-      "r=a/(1-a)\n",

-      "\n",

-      "#Results\n",

-      "print(\"time ratio(T_on/T_off)=%.3f\" %r)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "time ratio(T_on/T_off)=2.333\n"

-       ]

-      }

-     ],

-     "prompt_number": 3

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.5, Page No 390"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_o=660.0\n",

-      "V_s=220.0\n",

-      "\n",

-      "#Calculations\n",

-      "a=(V_o/V_s)/(1+(V_o/V_s))\n",

-      "T_on=120\n",

-      "T=T_on/a\n",

-      "T_off=T-T_on \n",

-      "T_off=3*T_off\n",

-      "T_on=T-T_off\n",

-      "a=T_on/(T_on+T_off)\n",

-      "V_o=V_s*(a/(1-a))   \n",

-      "\n",

-      "#Results\n",

-      "print(\"pulse width o/p voltage=%.0f us\" %T_off)\n",

-      "print(\"\\nnew o/p voltage=%.2f V\" %V_o)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "pulse width o/p voltage=120 us\n",

-        "\n",

-        "new o/p voltage=73.33 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 4

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.11 Page No 408"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "R=1.0\n",

-      "L=.005\n",

-      "T_a=L/R\n",

-      "T=2000*10**-6\n",

-      "E=24.0\n",

-      "V_s=220\n",

-      "T_on=600*10**-6\n",

-      "a=T_on/T\n",

-      "\n",

-      "#Calculations\n",

-      "a1=(T_a/T)*math.log(1+(E/V_s)*((math.exp(T/T_a))-1))\n",

-      "if a1<a :\n",

-      "    print(\"load current in continuous\")\n",

-      "else:\n",

-      "    print(\"load current in discont.\")\n",

-      "\n",

-      "I_o=(a*V_s-E)/R    \n",

-      "I_mx=(V_s/R)*((1-math.exp(-T_on/T_a))/(1-math.exp(-T/T_a)))-E/R    \n",

-      "I_mn=(V_s/R)*((math.exp(T_on/T_a)-1)/(math.exp(T/T_a)-1))-E/R    \n",

-      "f=1/T\n",

-      "w=2*math.pi*f\n",

-      "I1=(2*V_s/(math.sqrt(2)*math.pi)*math.sin(math.radians(180*a)))/(math.sqrt(R**2+(w*L)**2))    \n",

-      "I2=(2*V_s/(2*math.sqrt(2)*math.pi)*math.sin(math.radians(2*180*a)))/(math.sqrt(R**2+(w*L*2)**2))    \n",

-      "I3=(2*V_s/(3*math.sqrt(2)*math.pi)*math.sin(math.radians(3*180*a)))/(math.sqrt(R**2+(w*L*3)**2))    \n",

-      "I_TAV=a*(V_s-E)/R-L*(I_mx-I_mn)/(R*T)   \n",

-      "P1=I_TAV*V_s\n",

-      "P2=E*I_o\n",

-      "I_or=math.sqrt(I_o**2+I1**2+I2**2+I3**2)\n",

-      "\n",

-      "#Results\n",

-      "print(\"avg o/p current=%.2f A\" %I_o)\n",

-      "print(\"max value of steady current=%.2f A\" %I_mx)\n",

-      "print(\"min value of steady current=%.2f A\" %I_mn)\n",

-      "print(\"first harmonic current=%.4f A\" %I1)\n",

-      "print(\"second harmonic current=%.4f A\" %I2)\n",

-      "print(\"third harmonic current=%.5f A\" %I3)\n",

-      "print(\"avg supply current=%.4f A\" %I_TAV)\n",

-      "print(\"i/p power=%.2f W\" %P1)\n",

-      "print(\"power absorbed by load emf=%.0f W\" %P2)\n",

-      "print(\"power loss in resistor=%.2f W\" %(P1-P2))\n",

-      "print(\"rms value of load current=%.3f A\" %I_or)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "load current in continuous\n",

-        "avg o/p current=42.00 A\n",

-        "max value of steady current=51.46 A\n",

-        "min value of steady current=33.03 A\n",

-        "first harmonic current=5.0903 A\n",

-        "second harmonic current=1.4983 A\n",

-        "third harmonic current=0.21643 A\n",

-        "avg supply current=12.7289 A\n",

-        "i/p power=2800.35 W\n",

-        "power absorbed by load emf=1008 W\n",

-        "power loss in resistor=1792.35 W\n",

-        "rms value of load current=42.334 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 7

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.12 Page No 411"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "R=1\n",

-      "L=.001\n",

-      "V_s=220\n",

-      "E=72.0\n",

-      "f=500.0\n",

-      "T_on=800*10**-6\n",

-      "T_a=L/R\n",

-      "T=1.0/f\n",

-      "m=E/V_s\n",

-      "a=T_on/T\n",

-      "\n",

-      "#Calculations\n",

-      "a1=(T_a/T)*math.log(1+m*(math.exp(-T/T_a)-1))\n",

-      "if a1>a :\n",

-      "    print(\"load current is continuous\")\n",

-      "else:\n",

-      "    print(\"load current is discontinuous\")\n",

-      "\n",

-      "t_x=T_on+L*math.log(1+((V_s-E)/272)*(1-math.exp(-T_on/T_a)))\n",

-      " #Value of t_x wrongly calculated in the book so ans of V_o and I_o varies\n",

-      "V_o=a*V_s+(1-t_x/T)*E    \n",

-      "I_o=(V_o-E)/R    \n",

-      "I_mx=(V_s-E)/R*(1-math.exp(-T_on/T_a)) \n",

-      "\n",

-      "#Results  \n",

-      "print(\"avg o/p voltage=%.2f V\" %V_o)\n",

-      "print(\"avg o/p current=%.2f A\" %I_o) \n",

-      "print(\"max value of load current=%.1f A\" %I_mx)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "load current is discontinuous\n",

-        "avg o/p voltage=121.77 V\n",

-        "avg o/p current=49.77 A\n",

-        "max value of load current=81.5 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 10

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.13, Page No 412"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "a=0.2\n",

-      "V_s=500\n",

-      "E=a*V_s\n",

-      "L=0.06\n",

-      "I=10\n",

-      "\n",

-      "#Calculations\n",

-      "T_on=(L*I)/(V_s-E)\n",

-      "f=a/T_on    \n",

-      "\n",

-      "#Results\n",

-      "print(\"chopping freq=%.2f Hz\" %f)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "chopping freq=133.33 Hz\n"

-       ]

-      }

-     ],

-     "prompt_number": 11

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.14 Page No 412"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "a=0.5\n",

-      "pu=0.1 #pu ripple\n",

-      "\n",

-      "#Calculations\n",

-      " #x=T/T_a\n",

-      " #y=exp(-a*x)\n",

-      "y=(1-pu)/(1+pu)\n",

-      " #after solving\n",

-      "x=math.log(1/y)/a\n",

-      "f=1000\n",

-      "T=1/f\n",

-      "T_a=T/x\n",

-      "R=2\n",

-      "L=R*T_a\n",

-      "Li=0.002\n",

-      "Le=L-Li    \n",

-      "\n",

-      "#Results\n",

-      "print(\"external inductance=%.3f mH\" %(Le*1000))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "external inductance=-2.000 mH\n"

-       ]

-      }

-     ],

-     "prompt_number": 12

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.15 Page No 414"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "R=10.0\n",

-      "L=0.015\n",

-      "T_a=L/R\n",

-      "f=1250.0\n",

-      "T=1.0/f\n",

-      "a=0.5\n",

-      "T_on=a*T\n",

-      "V_s=220.0\n",

-      "\n",

-      "#Calculations\n",

-      "I_mx=(V_s/R)*((1-math.exp(-T_on/T_a))/(1-math.exp(-T/T_a)))   \n",

-      "I_mn=(V_s/R)*((math.exp(T_on/T_a)-1)/(math.exp(T/T_a)-1))    \n",

-      "dI=I_mx-I_mn    \n",

-      "V_o=a*V_s\n",

-      "I_o=V_o/R    \n",

-      "I_or=math.sqrt(I_mx**2+dI**2/3+I_mx*dI)    \n",

-      "I_chr=math.sqrt(a)*I_or \n",

-      "\n",

-      "#Results\n",

-      "print(\"Max value of ripple current=%.2f A\" %dI)\n",

-      "print(\"Max value of load current=%.3f A\" %I_mx)\n",

-      "print(\"Min value of load current=%.2f A\" %I_mn)\n",

-      "print(\"Avg value of load current=%.2f A\" %I_o)   \n",

-      "print(\"rms value of load current=%.2f A\" %I_or)\n",

-      "print(\"rms value of chopper current=%.2f A\" %I_chr)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Max value of ripple current=2.92 A\n",

-        "Max value of load current=12.458 A\n",

-        "Min value of load current=9.54 A\n",

-        "Avg value of load current=11.00 A\n",

-        "rms value of load current=13.94 A\n",

-        "rms value of chopper current=9.86 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 14

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.17 Page No 417"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "L=0.0016\n",

-      "C=4*10**-6\n",

-      "\n",

-      "#Calculations\n",

-      "w=1/math.sqrt(L*C)\n",

-      "t=math.pi/w    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"time for which current flows=%.2f us\" %(t*10**6))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "time for which current flows=251.33 us\n"

-       ]

-      }

-     ],

-     "prompt_number": 15

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.18, Page No 424"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "t_q=20.0*10**-6\n",

-      "dt=20.0*10**-6\n",

-      "\n",

-      "#Calculations\n",

-      "t_c=t_q+dt\n",

-      "I_0=60.0\n",

-      "V_s=60.0\n",

-      "C=t_c*I_0/V_s \n",

-      "\n",

-      "#Results   \n",

-      "print(\"value of commutating capacitor=%.0f uF\" %(C*10**6))\n",

-      "\n",

-      "L1=(V_s/I_0)**2*C\n",

-      "L2=(2*t_c/math.pi)**2/C\n",

-      "if L1>L2 :\n",

-      "    print(\"value of commutating inductor=%.0f uH\" %(L1*10**6))\n",

-      "else:\n",

-      "    print(\"value of commutating inductor=%.0f uH\" %(L2*10**6))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "value of commutating capacitor=40 uF\n",

-        "value of commutating inductor=40 uH\n"

-       ]

-      }

-     ],

-     "prompt_number": 19

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.19, Page No 424"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "t=100.0*10**-6\n",

-      "R=10.0\n",

-      "\n",

-      "#Calculations\n",

-      " #V_s*(1-2*math.exp(-t/(R*C)))=0\n",

-      "C=-t/(R*math.log(1.0/2))    \n",

-      "L=(4/9.0)*C*R**2    \n",

-      "L=(1.0/4)*C*R**2    \n",

-      "\n",

-      "#Results\n",

-      "print(\"Value of comutating component C=%.3f uF\" %(C*10**6))\n",

-      "print(\"max permissible current through SCR is 2.5 times load current\")\n",

-      "print(\"value of comutating component L=%.1f uH\" %(L*10**6))\n",

-      "print(\"max permissible current through SCR is 1.5 times peak diode current\")\n",

-      "print(\"value of comutating component L=%.2f uH\" %(L*10**6))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Value of comutating component C=14.427 uF\n",

-        "max permissible current through SCR is 2.5 times load current\n",

-        "value of comutating component L=360.7 uH\n",

-        "max permissible current through SCR is 1.5 times peak diode current\n",

-        "value of comutating component L=360.67 uH\n"

-       ]

-      }

-     ],

-     "prompt_number": 20

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.20, Page No 426"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "T_on=800.0*10**-6\n",

-      "V_s=220.0\n",

-      "I_o=80.0\n",

-      "C=50*10**-6\n",

-      "\n",

-      "#Calculations\n",

-      "T=T_on+2*V_s*C/I_o    \n",

-      "L=20*10**-6\n",

-      "C=50*10**-6\n",

-      "i_T1=I_o+V_s*math.sqrt(C/L)    \n",

-      "i_TA=I_o    \n",

-      "t_c=C*V_s/I_o    \n",

-      "t_c1=(math.pi/2)*math.sqrt(L*C)    \n",

-      "t=150*10**-6\n",

-      "v_c=I_o*t/C-V_s  \n",

-      "\n",

-      "#Results  \n",

-      "print(\"effective on period=%.0f us\" %(T*10**6))\n",

-      "print(\"peak current through main thyristor=%.2f A\" %i_T1)\n",

-      "print(\"peak current through auxillery thyristor=%.0f A\" %i_TA)\n",

-      "print(\"turn off time for main thyristor=%.1f us\" %(t_c*10**6))\n",

-      "print(\"turn off time for auxillery thyristor=%.3f us\" %(t_c1*10**6))\n",

-      "print(\"total commutation interval=%.0f us\" %(2*t_c*10**6))\n",

-      "print(\"capacitor voltage=%.0f V\" %v_c)\n",

-      "print(\"time nedded to recharge the capacitor=%.0f us\" %(2*V_s*C/I_o*10**6))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for firing angle = 30deg\n",

-        "avg output voltage=232.509 V\n",

-        "for firing angle = 60deg\n",

-        "avg output voltage=133.65 V\n",

-        "avg current rating=12 A\n",

-        "rms current rating=20.785 A\n",

-        "PIV of SCR=565.7 V\n",

-        "power dissipated=16.8 W\n"

-       ]

-      }

-     ],

-     "prompt_number": 122

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.21, Page No 427"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "I_o=260.0\n",

-      "V_s=220.0\n",

-      "fos=2 #factor of safety\n",

-      "\n",

-      "#Calculations\n",

-      "t_off=18*10**-6\n",

-      "t_c=2*t_off\n",

-      "C=t_c*I_o/V_s    \n",

-      "L=(V_s/(0.8*I_o))**2*C    \n",

-      "f=400\n",

-      "a_mn=math.pi*f*math.sqrt(L*C)\n",

-      "V_omn=V_s*(a_mn+2*f*t_c)    \n",

-      "V_omx=V_s    \n",

-      "\n",

-      "#Results\n",

-      "print(\"Value of C=%.3f uF\" %(C*10**6))\n",

-      "print(\"value of L=%.3f uH\" %(L*10**6))\n",

-      "print(\"min value of o/p voltage=%.3f V\" %V_omn)\n",

-      "print(\"max value of o/p voltage=%.0f V\" %V_omx)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "firing angle delay=47.461 deg\n",

-        "pf=0.646\n",

-        "firing angle delay=127.71 deg\n"

-       ]

-      }

-     ],

-     "prompt_number": "*"

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.22, Page No 434"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "x=2.0\n",

-      "t_q=30*10**-6\n",

-      "dt=30*10**-6\n",

-      "t_c=t_q+dt\n",

-      "V_s=230.0\n",

-      "I_o=200.0\n",

-      "\n",

-      "#Calculations\n",

-      "L=V_s*t_c/(x*I_o*(math.pi-2*math.asin(1/x)))    \n",

-      "C=x*I_o*t_c/(V_s*(math.pi-2*math.asin(1/x)))    \n",

-      "V_cp=V_s+I_o*math.sqrt(L/C)    \n",

-      "I_cp=x*I_o    \n",

-      "x=3\n",

-      "L=V_s*t_c/(x*I_o*(math.pi-2*math.asin(1/x)))   \n",

-      "C=x*I_o*t_c/(V_s*(math.pi-2*math.asin(1/x)))    \n",

-      "V_cp=V_s+I_o*math.sqrt(L/C)    \n",

-      "I_cp=x*I_o    \n",

-      "\n",

-      "#Results\n",

-      "print(\"value of commutating inductor=%.3f uH\" %(L*10**6))\n",

-      "print(\"value of commutating capacitor=%.3f uF\" %(C*10**6))\n",

-      "print(\"peak capacitor voltage=%.0f V\" %V_cp)\n",

-      "print(\"peak commutataing current=%.0f A\" %I_cp)\n",

-      "print(\"value of commutating inductor=%.3f uH\" %(L*10**6))\n",

-      "print(\"value of commutating capacitor=%.3f uF\" %(C*10**6))\n",

-      "print(\"peak capacitor voltage=%.2f V\" %V_cp)\n",

-      "print(\"peak commutataing current=%.0f A\" %I_cp)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "value of commutating inductor=7.321 uH\n",

-        "value of commutating capacitor=49.822 uF\n",

-        "peak capacitor voltage=307 V\n",

-        "peak commutataing current=600 A\n",

-        "value of commutating inductor=7.321 uH\n",

-        "value of commutating capacitor=49.822 uF\n",

-        "peak capacitor voltage=306.67 V\n",

-        "peak commutataing current=600 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 25

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.23, Page No 434"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variablesV_s=230\n",

-      "C=50*10**-6\n",

-      "L=20*10**-6\n",

-      "I_cp=V_s*math.sqrt(C/L)\n",

-      "I_o=200\n",

-      "x=I_cp/I_o\n",

-      "\n",

-      "#Calculations\n",

-      "t_c=(math.pi-2*math.asin(1/x))*math.sqrt(C*L)   \n",

-      "th1=math.degrees(math.asin(1.0/x))\n",

-      "t=(5*math.pi/2-th1*math.pi/180)*math.sqrt(L*C)+C*V_s*(1-math.cos(math.radians(th1)))/I_o    \n",

-      "t=(math.pi-th1*math.pi/180)*math.sqrt(L*C)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"turn off time of main thyristor=%.2f us\" %(t_c*10**6))\n",

-      "print(\"total commutation interval=%.3f us\" %(t*10**6))\n",

-      "print(\"turn off time of auxillery thyristor=%.3f us\" %(t*10**6))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "turn off time of main thyristor=62.52 us\n",

-        "total commutation interval=80.931 us\n",

-        "turn off time of auxillery thyristor=80.931 us\n"

-       ]

-      }

-     ],

-     "prompt_number": 27

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.24, Page No 440"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "tc=0.006\n",

-      "R=10.0\n",

-      "L=R*tc\n",

-      "f=2000.0\n",

-      "\n",

-      "#Calculations\n",

-      "T=1/f\n",

-      "V_o=50.0\n",

-      "V_s=100.0\n",

-      "a=V_o/V_s\n",

-      "T_on=a*T\n",

-      "T_off=T-T_on\n",

-      "dI=V_o*T_off/L\n",

-      "I_o=V_o/R\n",

-      "I2=I_o+dI/2    \n",

-      "I1=I_o-dI/2    \n",

-      "\n",

-      "#Results\n",

-      "print(\"max value of load current=%.3f A\" %I2)\n",

-      "print(\"min value of load current=%.3f A\" %I1)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "max value of load current=5.104 A\n",

-        "min value of load current=4.896 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 28

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.27, Page No 443"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "I_a=30.0\n",

-      "r_a=.5\n",

-      "V_s=220.0\n",

-      "\n",

-      "#Calculations\n",

-      "a=I_a*r_a/V_s    \n",

-      "a=1\n",

-      "k=.1 #V/rpm\n",

-      "N=(a*V_s-I_a*r_a)/k    \n",

-      "\n",

-      "#Results\n",

-      "print(\"min value of duty cycle=%.3f\" %a)\n",

-      "print(\"min Value of speed control=%.0f rpm\" %0)\n",

-      "print(\"max value of duty cycle=%.0f\" %a)\n",

-      "print(\"max value of speed control=%.0f rpm\" %N)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "min value of duty cycle=1.000\n",

-        "min Value of speed control=0 rpm\n",

-        "max value of duty cycle=1\n",

-        "max value of speed control=2050 rpm\n"

-       ]

-      }

-     ],

-     "prompt_number": 29

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.28, Page No 444"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_t=72.0\n",

-      "I_a=200.0\n",

-      "r_a=0.045\n",

-      "N=2500.0\n",

-      "\n",

-      "#Calculations\n",

-      "k=(V_t-I_a*r_a)/N\n",

-      "E_a=k*1000\n",

-      "L=.007\n",

-      "Rm=.045\n",

-      "Rb=0.065\n",

-      "R=Rm+Rb\n",

-      "T_a=L/R\n",

-      "I_mx=230\n",

-      "I_mn=180\n",

-      "T_on=-T_a*math.log(-((V_t-E_a)/R-I_mx)/((I_mn)-(V_t-E_a)/R))\n",

-      "R=Rm\n",

-      "T_a=L/R\n",

-      "T_off=-T_a*math.log(-((-E_a)/R-I_mn)/((I_mx)-(-E_a)/R))\n",

-      "T=T_on+T_off\n",

-      "f=1/T    \n",

-      "a=T_on/T \n",

-      "\n",

-      "#Results\n",

-      "print(\"chopping freq=%.1f Hz\" %f)  \n",

-      "print(\"duty cycle ratio=%.3f\" %a)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "chopping freq=40.5 Hz\n",

-        "\n",

-        "duty cycle ratio=0.588\n"

-       ]

-      }

-     ],

-     "prompt_number": 30

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 7.29, Page No 445"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variablesI_mx=425\n",

-      "I_lt=180.0     #lower limit of current pulsation\n",

-      "I_mn=I_mx-I_lt\n",

-      "T_on=0.014\n",

-      "T_off=0.011\n",

-      "\n",

-      "#Calculations\n",

-      "T=T_on+T_off\n",

-      "T_a=.0635\n",

-      "a=T_on/T\n",

-      "V=(I_mx-I_mn*math.exp(-T_on/T_a))/(1-math.exp(-T_on/T_a))\n",

-      "a=.5\n",

-      "I_mn=(I_mx-V*(1-math.exp(-T_on/T_a)))/(math.exp(-T_on/T_a))\n",

-      "T=I_mx-I_mn    \n",

-      "T=T_on/a\n",

-      "f=1/T    \n",

-      "\n",

-      "#Results\n",

-      "print(\"higher limit of current pulsation=%.0f A\" %T)\n",

-      "print(\"chopping freq=%.3f Hz\" %f)\n",

-      "print(\"duty cycle ratio=%.2f\" %a)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "higher limit of current pulsation=0 A\n",

-        "chopping freq=35.714 Hz\n",

-        "duty cycle ratio=0.50\n"

-       ]

-      }

-     ],

-     "prompt_number": 32

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Power_Electronics/Chapter8.ipynb b/_Power_Electronics/Chapter8.ipynb
deleted file mode 100755
index 721a9faf..00000000
--- a/_Power_Electronics/Chapter8.ipynb
+++ /dev/null
@@ -1,984 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 08 : Inverters"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.3, Page No 465"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "T=0.1*10**-3\n",

-      "f=1.0/T\n",

-      "k=15*10**-6 #k=th/w\n",

-      "\n",

-      "#Calculations\n",

-      "th=2*math.pi*f*k\n",

-      "X_l=10.0\n",

-      "R=2.0\n",

-      "X_c=R*math.tan(th)+X_l\n",

-      "C=1/(2*math.pi*f*X_c)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"value of C=%.3f uF\" %(C*10**6))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "value of C=1.248 uF\n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.4 Page No 466"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_01=2*V_s/(math.sqrt(2)*math.pi)\n",

-      "R=2.0\n",

-      "I_01=V_01/R\n",

-      "P_d=I_01**2*R    \n",

-      "V=V_s/2\n",

-      "I_s=math.sqrt(2)*I_01/math.pi\n",

-      "P_s=V*I_s\n",

-      "\n",

-      "#Results\n",

-      "print(\"power delivered to load=%.1f W\" %P_d)\n",

-      "print(\"power delivered by both sources=%.1f W\" %(2*P_s))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "power delivered to load=5359.9 W\n",

-        "power delivered by both sources=5359.9 W\n"

-       ]

-      }

-     ],

-     "prompt_number": 2

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.5, Page No 468"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "V_01=4*V_s/(math.pi*math.sqrt(2))\n",

-      "R=1.0\n",

-      "X_L=6.0\n",

-      "X_c=7.0\n",

-      "\n",

-      "#Calculations\n",

-      "I_01=V_01/math.sqrt(R**2+(X_L-X_c)**2)\n",

-      "P=I_01**2*R    \n",

-      "I_s=math.sqrt(2)*I_01*(2*math.cos(math.radians(45)))/math.pi\n",

-      "P_s=V_s*I_s    \n",

-      "\n",

-      "#Results\n",

-      "print(\"power delivered to the source=%.3f kW\" %(P/1000))\n",

-      "print(\"\\npower from the source=%.3f kW\" %(P_s/1000))\n",

-      "   "

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "power delivered to the source=21.440 kW\n",

-        "\n",

-        "power from the source=21.440 kW\n"

-       ]

-      }

-     ],

-     "prompt_number": 3

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.6 Page No 469"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_01=230.0\n",

-      "R=2.0\n",

-      "I_01=V_01/R\n",

-      "I_m=I_01*math.sqrt(2)\n",

-      "I_T1=I_m/2    \n",

-      "I_D1=0    \n",

-      "X_L=8.0\n",

-      "X_C=6.0\n",

-      "\n",

-      "#Calculations\n",

-      "I_01=V_01/math.sqrt(R**2+(X_L-X_C)**2)\n",

-      "phi1=math.degrees(math.atan((X_L-X_C)/R))\n",

-      "I_T1=I_T1*math.sqrt(2)*0.47675    \n",

-      "I_D1=.1507025*I_m/math.sqrt(2)    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"when load R=2 ohm\")\n",

-      "print(\"rms value of thyristor current=%.2f A\" %I_T1)\n",

-      "print(\"rms value of diode current=%.0f A\" %I_D1)\n",

-      "print(\"when load R=2ohm % X_L=8ohm and X_C=6ohm\")\n",

-      "print(\"rms value of thyristor current=%.3f A\" %I_T1)\n",

-      "print(\"rms value of diode current=%.3f A\" %I_D1)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "when load R=2 ohm\n",

-        "rms value of thyristor current=54.83 A\n",

-        "rms value of diode current=17 A\n",

-        "when load R=2ohm % X_L=8ohm and X_C=6ohm\n",

-        "rms value of thyristor current=54.826 A\n",

-        "rms value of diode current=17.331 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 4

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.7 Page No 470"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "R=4.0\n",

-      "f=50.0\n",

-      "w=2*math.pi*f\n",

-      "L=0.035\n",

-      "\n",

-      "#Calculations\n",

-      "C=155*10**-6\n",

-      "X_L=w*L\n",

-      "X_C=1/(w*C)\n",

-      "Z1=math.sqrt(R**2+(X_L-X_C)**2)\n",

-      "phi1=-math.degrees(math.atan((X_L-X_C)/R))\n",

-      "Z3=math.sqrt(R**2+(X_L*3-X_C/3)**2)\n",

-      "phi3=math.degrees(math.atan((X_L*3-X_C/3)/R))\n",

-      "Z5=math.sqrt(R**2+(X_L*5-X_C/5)**2)\n",

-      "phi5=math.degrees(math.atan((X_L*5-X_C/5)/R))\n",

-      "I_m1=4*V_s/(Z1*math.pi)\n",

-      "I_01=I_m1/math.sqrt(2)    \n",

-      "I_m3=4*V_s/(3*Z3*math.pi)\n",

-      "I_m5=4*V_s/(5*Z5*math.pi)\n",

-      "I_m=math.sqrt(I_m1**2+I_m3**2+I_m5**2)\n",

-      "I_0=I_m/math.sqrt(2)\n",

-      "P_0=(I_0)**2*R    \n",

-      "P_01=(I_01)**2*R    \n",

-      "t1=(180-phi1)*math.pi/(180*w)    \n",

-      "t1=(phi1)*math.pi/(180*w)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"rms value of fundamental load current=%.2f A\" %I_01)\n",

-      "print(\"load power=%.1f W\" %P_0)\n",

-      "print(\"fundamental load power=%.1f W\" %P_01)\n",

-      "print(\"rms value of thyristor current=%.3f A\" %(I_m/2))\n",

-      "print(\"conduction time for thyristor=%.3f ms\" %(t1*1000))\n",

-      "print(\"Conduction time for diodes=%.3f ms\" %(t1*1000))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rms value of fundamental load current=20.02 A\n",

-        "load power=1632.5 W\n",

-        "fundamental load power=1602.6 W\n",

-        "rms value of thyristor current=14.285 A\n",

-        "conduction time for thyristor=3.736 ms\n",

-        "Conduction time for diodes=3.736 ms\n"

-       ]

-      }

-     ],

-     "prompt_number": 5

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.8, Page No 473"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "V_01=2*V_s/(math.sqrt(2)*math.pi)    \n",

-      "R=10.0\n",

-      "\n",

-      "#Calculations\n",

-      "I_01=V_01/R\n",

-      "P=I_01**2*R    \n",

-      "V_or=math.sqrt((V_s/2)**2)\n",

-      "P=V_or**2/R    \n",

-      "I_TP=V_s/(2*R)\n",

-      "I_or=I_TP\n",

-      "pf=I_01**2*R/(V_or*I_or)  \n",

-      "DF=V_01/V_or  \n",

-      "V_oh=math.sqrt(V_or**2-V_01**2)\n",

-      "THD=V_oh/V_01 \n",

-      "V_03=V_01/3\n",

-      "HF=V_03/V_01\n",

-      "\n",

-      "#Results\n",

-      "print(\"fundamental rms o/p voltage=%.3f V\" %V_01)\n",

-      "print(\"fundamental power to load=%.1f W\" %P)\n",

-      "print(\"total o/p power to load=%.1f W\" %P)\n",

-      "print(\"avg SCR current=%.2f A\" %(I_TP*180/360))\n",

-      "print(\"i/p pf=%.3f\" %pf)  \n",

-      "print(\"distortion factor=%.1f\" %DF)\n",

-      "print(\"THD=%.3f\" %THD)    \n",

-      "print(\"harmonic factor=%.4f\" %HF)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "fundamental rms o/p voltage=103.536 V\n",

-        "fundamental power to load=1322.5 W\n",

-        "total o/p power to load=1322.5 W\n",

-        "avg SCR current=5.75 A\n",

-        "i/p pf=0.811\n",

-        "distortion factor=0.9\n",

-        "THD=0.483\n",

-        "harmonic factor=0.3333\n"

-       ]

-      }

-     ],

-     "prompt_number": 6

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.9 Page No 474"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=60\n",

-      "R=3.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_or=math.sqrt(V_s**2*math.pi/math.pi)    \n",

-      "V_01=4*V_s/(math.sqrt(2)*math.pi)    \n",

-      "P_o=V_or**2/R    \n",

-      "P_01=V_01**2/R    \n",

-      "I_s=V_s/R    \n",

-      "I_avg=I_s*math.pi/(2*math.pi)    \n",

-      "V_03=V_01/3\n",

-      "HF=V_03/V_01    \n",

-      "V_oh=math.sqrt(V_or**2-V_01**2)\n",

-      "THD=V_oh/V_01   \n",

-      "\n",

-      "#Results\n",

-      "print(\"rms value of o/p voltage=%.0f V\" %V_or)\n",

-      "print(\"o/p power=%.0f W\" %P_o)\n",

-      "print(\"fundamental component of rms voltage=%.2f V\" %V_01)\n",

-      "print(\"fundamental freq o/p power=%.2f W\" %P_01) \n",

-      "print(\"peak current=%.0f A\" %I_s)\n",

-      "print(\"avg current of each transistor=%.0f A\" %I_avg)\n",

-      "print(\"peak reverse blocking voltage=%.0f V\" %V_s)\n",

-      "print(\"harmonic factor=%.4f\" %HF)\n",

-      "print(\"THD=%.4f\" %THD)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rms value of o/p voltage=60 V\n",

-        "o/p power=1200 W\n",

-        "fundamental component of rms voltage=54.02 V\n",

-        "fundamental freq o/p power=972.68 W\n",

-        "peak current=20 A\n",

-        "avg current of each transistor=10 A\n",

-        "peak reverse blocking voltage=60 V\n",

-        "harmonic factor=0.3333\n",

-        "THD=0.4834\n"

-       ]

-      }

-     ],

-     "prompt_number": 7

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.10 Page No 475"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=220.0\n",

-      "R=6.0\n",

-      "f=50.0\n",

-      "w=2*math.pi*f\n",

-      "L=0.03\n",

-      "C=180*10**-6\n",

-      "X_L=w*L\n",

-      "X_C=1/(w*C)\n",

-      "\n",

-      "#Calculations\n",

-      "V_or=math.sqrt(V_s**2*math.pi/math.pi)\n",

-      "V_01=4*V_s/(math.sqrt(2)*math.pi)\n",

-      "V_oh=math.sqrt(V_or**2-V_01**2)\n",

-      "THD=V_oh/V_01    \n",

-      "print(\"THD of voltage=%.4f\" %THD)\n",

-      "DF=V_01/V_or    \n",

-      "Z1=math.sqrt(R**2+(X_L-X_C)**2)\n",

-      "phi1=-math.degrees(math.atan((X_L-X_C)/R))\n",

-      "Z3=math.sqrt(R**2+(X_L*3-X_C/3)**2)\n",

-      "phi3=math.degrees(math.atan((X_L*3-X_C/3)/R))\n",

-      "Z5=math.sqrt(R**2+(X_L*5-X_C/5)**2)\n",

-      "phi5=math.degrees(math.atan((X_L*5-X_C/5)/R))\n",

-      "Z7=math.sqrt(R**2+(X_L*7-X_C/7)**2)\n",

-      "phi7=math.degrees(math.atan((X_L*7-X_C/7)/R))\n",

-      "I_01=19.403\n",

-      "I_m1=4*V_s/(Z1*math.pi)\n",

-      "I_m3=4*V_s/(3*Z3*math.pi)\n",

-      "I_m5=4*V_s/(5*Z5*math.pi)\n",

-      "I_m7=4*V_s/(7*Z7*math.pi)\n",

-      "I_m=math.sqrt(I_m1**2+I_m3**2+I_m5**2+I_m7**2)\n",

-      "I_or=I_m/math.sqrt(2)\n",

-      "I_oh=math.sqrt((I_m**2-I_m1**2)/2)\n",

-      "THD=I_oh/I_01    \n",

-      "DF=I_01/I_or    \n",

-      "P_o=I_or**2*R    \n",

-      "I_avg=P_o/V_s    \n",

-      "t1=(180-phi1)*math.pi/(180*w)    \n",

-      "t1=1/(2*f)-t1    \n",

-      "I_p=I_m1    \n",

-      "I_t1=.46135*I_p \n",

-      "\n",

-      "#Results\n",

-      "print(\"\\nDF=%.1f\" %DF)\n",

-      "print(\"THD of current=%.4f\" %THD)   \n",

-      "print(\"DF=%.3f\" %DF)\n",

-      "print(\"load power=%.1f W\" %P_o)\n",

-      "print(\"avg value of load current=%.2f A\" %I_avg)\n",

-      "print(\"conduction time for thyristor=%.0f ms\" %(t1*1000))\n",

-      "print(\"conduction time for diodes=%.0f ms\" %(t1*1000))\n",

-      "print(\"peak transistor current=%.2f A\" %I_p)\n",

-      "print(\"rms transistor current=%.2f A\" %I_t1)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "THD of voltage=0.4834\n",

-        "\n",

-        "DF=1.0\n",

-        "THD of current=0.1557\n",

-        "DF=0.988\n",

-        "load power=2313.5 W\n",

-        "avg value of load current=10.52 A\n",

-        "conduction time for thyristor=3 ms\n",

-        "conduction time for diodes=3 ms\n",

-        "peak transistor current=27.44 A\n",

-        "rms transistor current=12.66 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 8

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.11 Page No 497"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=450.0\n",

-      "R=10.0\n",

-      "\n",

-      "#Calculations\n",

-      "I_or=math.sqrt((V_s/(3*R))**2*2/3+(2*V_s/(3*R))**2*1/3)    \n",

-      "I_T1=math.sqrt((1/(2*math.pi))*((V_s/(3*R))**2*2*math.pi/3+(2*V_s/(3*R))**2*math.pi/3))   \n",

-      "P=3*I_or**2*R    \n",

-      "I_or=math.sqrt((1/(math.pi))*((V_s/(2*R))**2*2*math.pi/3))    \n",

-      "I_T1=math.sqrt((1/(2*math.pi))*((V_s/(2*R))**2*2*math.pi/3))    \n",

-      "P=3*I_or**2*R    \n",

-      "\n",

-      "#Results\n",

-      "print(\"for 180deg mode\")\n",

-      "print(\"rms value of load current=%.3f A\" %I_or)\n",

-      "print(\"power delivered to load=%.1f kW\" %(P/1000))\n",

-      "print(\"rms value of load current=%.0f A\" %I_T1)\n",

-      "print(\"for 120deg mode\")\n",

-      "print(\"rms value of load current=%.3f A\" %I_or)\n",

-      "print(\"rms value of load current=%.2f A\" %I_T1)\n",

-      "print(\"power delivered to load=%.3f kW\" %(P/1000))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for 180deg mode\n",

-        "rms value of load current=18.371 A\n",

-        "power delivered to load=10.1 kW\n",

-        "rms value of load current=13 A\n",

-        "for 120deg mode\n",

-        "rms value of load current=18.371 A\n",

-        "rms value of load current=12.99 A\n",

-        "power delivered to load=10.125 kW\n"

-       ]

-      }

-     ],

-     "prompt_number": 9

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.12, Page No 510"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "R=10.0\n",

-      "f=50.0\n",

-      "w=2*math.pi*f\n",

-      "L=0.03\n",

-      "\n",

-      "#Calculations\n",

-      "X_L=w*L\n",

-      "V_or=math.sqrt(V_s**2*math.pi/math.pi)\n",

-      "V_01=4*V_s/(math.sqrt(2)*math.pi)\n",

-      "Z1=math.sqrt(R**2+(X_L)**2)\n",

-      "phi1=-math.degrees(math.atan((X_L)/R))\n",

-      "Z3=math.sqrt(R**2+(X_L*3)**2)\n",

-      "phi3=math.degrees(math.atan((X_L*3)/R))\n",

-      "Z5=math.sqrt(R**2+(X_L*5)**2)\n",

-      "phi5=math.degrees(math.atan((X_L*5)/R))\n",

-      "Z7=math.sqrt(R**2+(X_L*7)**2)\n",

-      "phi7=math.degrees(math.atan((X_L*7)/R))\n",

-      "I_m1=4*V_s/(math.sqrt(2)*Z1*math.pi)\n",

-      "I_m3=4*V_s/(math.sqrt(2)*3*Z3*math.pi)\n",

-      "I_m5=4*V_s/(math.sqrt(2)*5*Z5*math.pi)\n",

-      "I_m7=4*V_s/(math.sqrt(2)*7*Z7*math.pi)\n",

-      "I_m=math.sqrt(I_m1**2+I_m3**2+I_m5**2+I_m7**2)\n",

-      "P=I_m**2*R    \n",

-      "I_01=I_m1*math.sin(math.radians(45))\n",

-      "I_03=I_m3*math.sin(math.radians(3*45))\n",

-      "I_05=I_m5*math.sin(math.radians(5*45))\n",

-      "I_07=I_m7*math.sin(math.radians(7*45))\n",

-      "I_0=(I_01**2+I_03**2+I_05**2+I_07**2)\n",

-      "P=I_0*R    \n",

-      "g=(180-90)/3+45/2\n",

-      "I_01=2*I_m1*math.sin(math.radians(g))*math.sin(math.radians(45/2))\n",

-      "I_03=2*I_m3*math.sin(math.radians(g*3))*math.sin(math.radians(3*45/2))\n",

-      "I_05=2*I_m5*math.sin(math.radians(g*5))*math.sin(math.radians(5*45/2))\n",

-      "I_07=2*I_m7*math.sin(math.radians(g*7))*math.sin(math.radians(7*45/2))\n",

-      "I_0=(I_01**2+I_03**2+I_05**2+I_07**2)\n",

-      "P=I_0*R    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"using square wave o/p\")\n",

-      "print(\"power delivered=%.2f W\" %P)\n",

-      "print(\"using quasi-square wave o/p\")\n",

-      "print(\"power delivered=%.2f W\" %P)\n",

-      "print(\"using two symmitrical spaced pulses\")\n",

-      "print(\"power delivered=%.2f W\" %P)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "using square wave o/p\n",

-        "power delivered=845.87 W\n",

-        "using quasi-square wave o/p\n",

-        "power delivered=845.87 W\n",

-        "using two symmitrical spaced pulses\n",

-        "power delivered=845.87 W\n"

-       ]

-      }

-     ],

-     "prompt_number": 10

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.14, Page No 520"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "f=50.0\n",

-      "T=1/f\n",

-      "I=0.5\n",

-      "\n",

-      "#Calculations\n",

-      "di=I/T     #di=di/dt\n",

-      "V_s=220.0\n",

-      "L=V_s/di    \n",

-      "t=20*10**-6\n",

-      "fos=2     #factor of safety\n",

-      "t_c=t*fos\n",

-      "R=10\n",

-      "C=t_c/(R*math.log(2))\n",

-      "\n",

-      "#Results    \n",

-      "print(\"source inductance=%.1f H\" %L)\n",

-      "print(\"commutating capacitor=%.2f uF\" %(C*10**6))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "source inductance=8.8 H\n",

-        "commutating capacitor=5.77 uF\n"

-       ]

-      }

-     ],

-     "prompt_number": 11

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.15, Page No 539"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "R=10.0\n",

-      "L=.01\n",

-      "C=10*10**-6\n",

-      "#Calculations\n",

-      "if (R**2)<(4*L/C) :\n",

-      "    print(\"ckt will commutate on its own\")\n",

-      "else:\n",

-      "    print(\"ckt will not commutate on its own\")\n",

-      "\n",

-      "xie=R/(2*L)\n",

-      "w_o=1/math.sqrt(L*C)\n",

-      "w_r=math.sqrt(w_o**2-xie**2)\n",

-      "phi=math.degrees(math.atan(xie/w_r))\n",

-      "t=math.pi/w_r\n",

-      "V_s=1\n",

-      "v_L=V_s*(w_o/w_r)*math.exp(-xie*t)*math.cos(math.radians(180+phi))\n",

-      "v_c=V_s*(1-(w_o/w_r)*math.exp(-xie*t)*math.cos(math.radians(180-phi)))   \n",

-      "di=V_s/L    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"voltage across inductor(*V_s)=%.5f V\" %v_L) \n",

-      "print(\"voltage across capacitor(*V_s)=%.5f V\" %v_c)\n",

-      "print(\"di/dt*V_s (for t=0)=%.0f A/s\" %di)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "ckt will commutate on its own\n",

-        "voltage across inductor(*V_s)=-0.60468 V\n",

-        "voltage across capacitor(*V_s)=1.60468 V\n",

-        "di/dt*V_s (for t=0)=100 A/s\n"

-       ]

-      }

-     ],

-     "prompt_number": 12

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.16, Page No 540"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "L=0.006\n",

-      "C=1.2*10**-6\n",

-      "R=100.0\n",

-      "\n",

-      "#Calculations\n",

-      "T=math.pi/math.sqrt(1/(L*C)-(R/(2*L))**2)\n",

-      "T_off=0.2*10**-3\n",

-      "f=1/(2*(T+T_off))    \n",

-      "R=40\n",

-      "T=math.pi/math.sqrt(1/(L*C)-(R/(2*L))**2)\n",

-      "T_off=.2*10**-3\n",

-      "f=1/(2*(T+T_off))    \n",

-      "R=140\n",

-      "T=math.pi/math.sqrt(1/(L*C)-(R/(2*L))**2)\n",

-      "T_off=.2*10**-3\n",

-      "f=1/(2*(T+T_off)) \n",

-      "\n",

-      "#Results\n",

-      "print(\"o/p freq=%.2f Hz\" %f)\n",

-      "print(\"for R=40ohm\")\n",

-      "print(\"upper limit o/p freq=%.1f Hz\" %f)\n",

-      "print(\"for R=140ohm\")\n",

-      "print(\"lower limit o/p freq=%.1f Hz\" %f)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "o/p freq=239.81 Hz\n",

-        "for R=40ohm\n",

-        "upper limit o/p freq=239.8 Hz\n",

-        "for R=140ohm\n",

-        "lower limit o/p freq=239.8 Hz\n"

-       ]

-      }

-     ],

-     "prompt_number": 13

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.17, Page No 540"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "f=5000.0\n",

-      "w=2*math.pi*f\n",

-      "R=3.0\n",

-      "\n",

-      "#Calculations\n",

-      "L=60*10**-6\n",

-      "xie=R/(2*L)\n",

-      "C=7.5*10**-6\n",

-      "w_o=1/math.sqrt(L*C)\n",

-      "w_r=math.sqrt(w_o**2-xie**2)\n",

-      "t_c=math.pi*(1/w-1/w_r)    \n",

-      "fos=1.5\n",

-      "t_q=10*10**-6\n",

-      "f_max=1/(2*math.pi*(t_q*fos/math.pi+1/w_r))    \n",

-      "\n",

-      "#Results\n",

-      "print(\"ckt turn off time=%.2f us\" %(t_c*10**6))\n",

-      "print(\"max possible operating freq=%.1f Hz\" %f_max)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "ckt turn off time=21.39 us\n",

-        "max possible operating freq=5341.4 Hz\n"

-       ]

-      }

-     ],

-     "prompt_number": 14

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.18, Page No 541"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "a=30.0\n",

-      "R=10.0\n",

-      "P=5000.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_s=math.sqrt(P*R*2*math.pi/(2*3)/(math.pi/3+math.sqrt(3)*math.cos(math.radians(2*a))/2))\n",

-      "V_ph=V_s/math.sqrt(3)    \n",

-      "I_or=math.sqrt(P*R)\n",

-      "V_s=I_or*math.pi/(math.sqrt(2)*3*math.cos(math.radians(a)))\n",

-      "V_ph=V_s/math.sqrt(3) \n",

-      "\n",

-      "#Results\n",

-      "print(\"per phase voltage  V_ph=%.3f V\" %V_ph)   \n",

-      "print(\"for constant load current\")\n",

-      "print(\"V_ph=%.2f V\" %V_ph)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "per phase voltage  V_ph=110.384 V\n",

-        "for constant load current\n",

-        "V_ph=110.38 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 15

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.19, Page No 547"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "t=20.0\n",

-      "fos=2.0     #factor of safety\n",

-      "\n",

-      "#Calculations\n",

-      "t_c=t*fos\n",

-      "n=1.0/3\n",

-      "R=20.0\n",

-      "C=n**2*t_c/(4*R*math.log(2)) \n",

-      "\n",

-      "#Results   \n",

-      "print(\"value of capacitor=%.2f uF\" %C)\n",

-      " #printing mistake in the answer in book."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "value of capacitor=0.08 uF\n"

-       ]

-      }

-     ],

-     "prompt_number": 16

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.20, Page No 547"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=220.0\n",

-      "V_p=math.sqrt(2)*V_s/3    \n",

-      "V_L=math.sqrt(3)*V_p    \n",

-      "V_p1=math.sqrt(2)*V_s/math.pi    \n",

-      "V_L1=math.sqrt(3)*V_p1    \n",

-      "V_oh=math.sqrt(V_L**2-V_L1**2)\n",

-      "\n",

-      "#Calculations\n",

-      "THD=V_oh/V_L1    \n",

-      "V_a1=2*V_s/math.pi\n",

-      "V_a5=2*V_s/(5*math.pi)\n",

-      "V_a7=2*V_s/(7*math.pi)\n",

-      "V_a11=2*V_s/(11*math.pi)\n",

-      "R=4.0\n",

-      "L=0.02\n",

-      "f=50\n",

-      "w=2*math.pi*f\n",

-      "Z1=math.sqrt(R**2+(w*L)**2)\n",

-      "Z5=math.sqrt(R**2+(5*w*L)**2)\n",

-      "Z7=math.sqrt(R**2+(7*w*L)**2)\n",

-      "Z11=math.sqrt(R**2+(11*w*L)**2)\n",

-      "I_a1=V_a1/Z1\n",

-      "I_a5=V_a5/Z5\n",

-      "I_a7=V_a7/Z7\n",

-      "I_a11=V_a11/Z11\n",

-      "I_or=math.sqrt((I_a1**2+I_a5**2+I_a7**2+I_a11**2)/2)\n",

-      "P=3*I_or**2*R    \n",

-      "I_s=P/V_s    \n",

-      "I_TA=I_s/3   \n",

-      " \n",

-      "#Results\n",

-      "print(\"rms value of phasor voltages=%.2f V\" %V_p)\n",

-      "print(\"rms value of line voltages=%.2f V\" %V_L)\n",

-      "print(\"fundamental component of phase voltage=%.3f V\" %V_p1)\n",

-      "print(\"fundamental component of line voltages=%.3f V\" %V_L1)\n",

-      "print(\"THD=%.7f\" %THD)\n",

-      "print(\"load power=%.1f W\" %P)\n",

-      "print(\"avg value of source current=%.3f A\" %I_s)\n",

-      "print(\"avg value of thyristor current=%.3f A\" %I_TA)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rms value of phasor voltages=103.71 V\n",

-        "rms value of line voltages=179.63 V\n",

-        "fundamental component of phase voltage=99.035 V\n",

-        "fundamental component of line voltages=171.533 V\n",

-        "THD=0.3108419\n",

-        "load power=2127.6 W\n",

-        "avg value of source current=9.671 A\n",

-        "avg value of thyristor current=3.224 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 17

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Power_Electronics/Chapter8_1.ipynb b/_Power_Electronics/Chapter8_1.ipynb
deleted file mode 100755
index 721a9faf..00000000
--- a/_Power_Electronics/Chapter8_1.ipynb
+++ /dev/null
@@ -1,984 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 08 : Inverters"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.3, Page No 465"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "T=0.1*10**-3\n",

-      "f=1.0/T\n",

-      "k=15*10**-6 #k=th/w\n",

-      "\n",

-      "#Calculations\n",

-      "th=2*math.pi*f*k\n",

-      "X_l=10.0\n",

-      "R=2.0\n",

-      "X_c=R*math.tan(th)+X_l\n",

-      "C=1/(2*math.pi*f*X_c)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"value of C=%.3f uF\" %(C*10**6))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "value of C=1.248 uF\n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.4 Page No 466"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_01=2*V_s/(math.sqrt(2)*math.pi)\n",

-      "R=2.0\n",

-      "I_01=V_01/R\n",

-      "P_d=I_01**2*R    \n",

-      "V=V_s/2\n",

-      "I_s=math.sqrt(2)*I_01/math.pi\n",

-      "P_s=V*I_s\n",

-      "\n",

-      "#Results\n",

-      "print(\"power delivered to load=%.1f W\" %P_d)\n",

-      "print(\"power delivered by both sources=%.1f W\" %(2*P_s))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "power delivered to load=5359.9 W\n",

-        "power delivered by both sources=5359.9 W\n"

-       ]

-      }

-     ],

-     "prompt_number": 2

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.5, Page No 468"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "V_01=4*V_s/(math.pi*math.sqrt(2))\n",

-      "R=1.0\n",

-      "X_L=6.0\n",

-      "X_c=7.0\n",

-      "\n",

-      "#Calculations\n",

-      "I_01=V_01/math.sqrt(R**2+(X_L-X_c)**2)\n",

-      "P=I_01**2*R    \n",

-      "I_s=math.sqrt(2)*I_01*(2*math.cos(math.radians(45)))/math.pi\n",

-      "P_s=V_s*I_s    \n",

-      "\n",

-      "#Results\n",

-      "print(\"power delivered to the source=%.3f kW\" %(P/1000))\n",

-      "print(\"\\npower from the source=%.3f kW\" %(P_s/1000))\n",

-      "   "

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "power delivered to the source=21.440 kW\n",

-        "\n",

-        "power from the source=21.440 kW\n"

-       ]

-      }

-     ],

-     "prompt_number": 3

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.6 Page No 469"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_01=230.0\n",

-      "R=2.0\n",

-      "I_01=V_01/R\n",

-      "I_m=I_01*math.sqrt(2)\n",

-      "I_T1=I_m/2    \n",

-      "I_D1=0    \n",

-      "X_L=8.0\n",

-      "X_C=6.0\n",

-      "\n",

-      "#Calculations\n",

-      "I_01=V_01/math.sqrt(R**2+(X_L-X_C)**2)\n",

-      "phi1=math.degrees(math.atan((X_L-X_C)/R))\n",

-      "I_T1=I_T1*math.sqrt(2)*0.47675    \n",

-      "I_D1=.1507025*I_m/math.sqrt(2)    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"when load R=2 ohm\")\n",

-      "print(\"rms value of thyristor current=%.2f A\" %I_T1)\n",

-      "print(\"rms value of diode current=%.0f A\" %I_D1)\n",

-      "print(\"when load R=2ohm % X_L=8ohm and X_C=6ohm\")\n",

-      "print(\"rms value of thyristor current=%.3f A\" %I_T1)\n",

-      "print(\"rms value of diode current=%.3f A\" %I_D1)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "when load R=2 ohm\n",

-        "rms value of thyristor current=54.83 A\n",

-        "rms value of diode current=17 A\n",

-        "when load R=2ohm % X_L=8ohm and X_C=6ohm\n",

-        "rms value of thyristor current=54.826 A\n",

-        "rms value of diode current=17.331 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 4

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.7 Page No 470"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "R=4.0\n",

-      "f=50.0\n",

-      "w=2*math.pi*f\n",

-      "L=0.035\n",

-      "\n",

-      "#Calculations\n",

-      "C=155*10**-6\n",

-      "X_L=w*L\n",

-      "X_C=1/(w*C)\n",

-      "Z1=math.sqrt(R**2+(X_L-X_C)**2)\n",

-      "phi1=-math.degrees(math.atan((X_L-X_C)/R))\n",

-      "Z3=math.sqrt(R**2+(X_L*3-X_C/3)**2)\n",

-      "phi3=math.degrees(math.atan((X_L*3-X_C/3)/R))\n",

-      "Z5=math.sqrt(R**2+(X_L*5-X_C/5)**2)\n",

-      "phi5=math.degrees(math.atan((X_L*5-X_C/5)/R))\n",

-      "I_m1=4*V_s/(Z1*math.pi)\n",

-      "I_01=I_m1/math.sqrt(2)    \n",

-      "I_m3=4*V_s/(3*Z3*math.pi)\n",

-      "I_m5=4*V_s/(5*Z5*math.pi)\n",

-      "I_m=math.sqrt(I_m1**2+I_m3**2+I_m5**2)\n",

-      "I_0=I_m/math.sqrt(2)\n",

-      "P_0=(I_0)**2*R    \n",

-      "P_01=(I_01)**2*R    \n",

-      "t1=(180-phi1)*math.pi/(180*w)    \n",

-      "t1=(phi1)*math.pi/(180*w)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"rms value of fundamental load current=%.2f A\" %I_01)\n",

-      "print(\"load power=%.1f W\" %P_0)\n",

-      "print(\"fundamental load power=%.1f W\" %P_01)\n",

-      "print(\"rms value of thyristor current=%.3f A\" %(I_m/2))\n",

-      "print(\"conduction time for thyristor=%.3f ms\" %(t1*1000))\n",

-      "print(\"Conduction time for diodes=%.3f ms\" %(t1*1000))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rms value of fundamental load current=20.02 A\n",

-        "load power=1632.5 W\n",

-        "fundamental load power=1602.6 W\n",

-        "rms value of thyristor current=14.285 A\n",

-        "conduction time for thyristor=3.736 ms\n",

-        "Conduction time for diodes=3.736 ms\n"

-       ]

-      }

-     ],

-     "prompt_number": 5

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.8, Page No 473"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "V_01=2*V_s/(math.sqrt(2)*math.pi)    \n",

-      "R=10.0\n",

-      "\n",

-      "#Calculations\n",

-      "I_01=V_01/R\n",

-      "P=I_01**2*R    \n",

-      "V_or=math.sqrt((V_s/2)**2)\n",

-      "P=V_or**2/R    \n",

-      "I_TP=V_s/(2*R)\n",

-      "I_or=I_TP\n",

-      "pf=I_01**2*R/(V_or*I_or)  \n",

-      "DF=V_01/V_or  \n",

-      "V_oh=math.sqrt(V_or**2-V_01**2)\n",

-      "THD=V_oh/V_01 \n",

-      "V_03=V_01/3\n",

-      "HF=V_03/V_01\n",

-      "\n",

-      "#Results\n",

-      "print(\"fundamental rms o/p voltage=%.3f V\" %V_01)\n",

-      "print(\"fundamental power to load=%.1f W\" %P)\n",

-      "print(\"total o/p power to load=%.1f W\" %P)\n",

-      "print(\"avg SCR current=%.2f A\" %(I_TP*180/360))\n",

-      "print(\"i/p pf=%.3f\" %pf)  \n",

-      "print(\"distortion factor=%.1f\" %DF)\n",

-      "print(\"THD=%.3f\" %THD)    \n",

-      "print(\"harmonic factor=%.4f\" %HF)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "fundamental rms o/p voltage=103.536 V\n",

-        "fundamental power to load=1322.5 W\n",

-        "total o/p power to load=1322.5 W\n",

-        "avg SCR current=5.75 A\n",

-        "i/p pf=0.811\n",

-        "distortion factor=0.9\n",

-        "THD=0.483\n",

-        "harmonic factor=0.3333\n"

-       ]

-      }

-     ],

-     "prompt_number": 6

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.9 Page No 474"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=60\n",

-      "R=3.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_or=math.sqrt(V_s**2*math.pi/math.pi)    \n",

-      "V_01=4*V_s/(math.sqrt(2)*math.pi)    \n",

-      "P_o=V_or**2/R    \n",

-      "P_01=V_01**2/R    \n",

-      "I_s=V_s/R    \n",

-      "I_avg=I_s*math.pi/(2*math.pi)    \n",

-      "V_03=V_01/3\n",

-      "HF=V_03/V_01    \n",

-      "V_oh=math.sqrt(V_or**2-V_01**2)\n",

-      "THD=V_oh/V_01   \n",

-      "\n",

-      "#Results\n",

-      "print(\"rms value of o/p voltage=%.0f V\" %V_or)\n",

-      "print(\"o/p power=%.0f W\" %P_o)\n",

-      "print(\"fundamental component of rms voltage=%.2f V\" %V_01)\n",

-      "print(\"fundamental freq o/p power=%.2f W\" %P_01) \n",

-      "print(\"peak current=%.0f A\" %I_s)\n",

-      "print(\"avg current of each transistor=%.0f A\" %I_avg)\n",

-      "print(\"peak reverse blocking voltage=%.0f V\" %V_s)\n",

-      "print(\"harmonic factor=%.4f\" %HF)\n",

-      "print(\"THD=%.4f\" %THD)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rms value of o/p voltage=60 V\n",

-        "o/p power=1200 W\n",

-        "fundamental component of rms voltage=54.02 V\n",

-        "fundamental freq o/p power=972.68 W\n",

-        "peak current=20 A\n",

-        "avg current of each transistor=10 A\n",

-        "peak reverse blocking voltage=60 V\n",

-        "harmonic factor=0.3333\n",

-        "THD=0.4834\n"

-       ]

-      }

-     ],

-     "prompt_number": 7

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.10 Page No 475"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=220.0\n",

-      "R=6.0\n",

-      "f=50.0\n",

-      "w=2*math.pi*f\n",

-      "L=0.03\n",

-      "C=180*10**-6\n",

-      "X_L=w*L\n",

-      "X_C=1/(w*C)\n",

-      "\n",

-      "#Calculations\n",

-      "V_or=math.sqrt(V_s**2*math.pi/math.pi)\n",

-      "V_01=4*V_s/(math.sqrt(2)*math.pi)\n",

-      "V_oh=math.sqrt(V_or**2-V_01**2)\n",

-      "THD=V_oh/V_01    \n",

-      "print(\"THD of voltage=%.4f\" %THD)\n",

-      "DF=V_01/V_or    \n",

-      "Z1=math.sqrt(R**2+(X_L-X_C)**2)\n",

-      "phi1=-math.degrees(math.atan((X_L-X_C)/R))\n",

-      "Z3=math.sqrt(R**2+(X_L*3-X_C/3)**2)\n",

-      "phi3=math.degrees(math.atan((X_L*3-X_C/3)/R))\n",

-      "Z5=math.sqrt(R**2+(X_L*5-X_C/5)**2)\n",

-      "phi5=math.degrees(math.atan((X_L*5-X_C/5)/R))\n",

-      "Z7=math.sqrt(R**2+(X_L*7-X_C/7)**2)\n",

-      "phi7=math.degrees(math.atan((X_L*7-X_C/7)/R))\n",

-      "I_01=19.403\n",

-      "I_m1=4*V_s/(Z1*math.pi)\n",

-      "I_m3=4*V_s/(3*Z3*math.pi)\n",

-      "I_m5=4*V_s/(5*Z5*math.pi)\n",

-      "I_m7=4*V_s/(7*Z7*math.pi)\n",

-      "I_m=math.sqrt(I_m1**2+I_m3**2+I_m5**2+I_m7**2)\n",

-      "I_or=I_m/math.sqrt(2)\n",

-      "I_oh=math.sqrt((I_m**2-I_m1**2)/2)\n",

-      "THD=I_oh/I_01    \n",

-      "DF=I_01/I_or    \n",

-      "P_o=I_or**2*R    \n",

-      "I_avg=P_o/V_s    \n",

-      "t1=(180-phi1)*math.pi/(180*w)    \n",

-      "t1=1/(2*f)-t1    \n",

-      "I_p=I_m1    \n",

-      "I_t1=.46135*I_p \n",

-      "\n",

-      "#Results\n",

-      "print(\"\\nDF=%.1f\" %DF)\n",

-      "print(\"THD of current=%.4f\" %THD)   \n",

-      "print(\"DF=%.3f\" %DF)\n",

-      "print(\"load power=%.1f W\" %P_o)\n",

-      "print(\"avg value of load current=%.2f A\" %I_avg)\n",

-      "print(\"conduction time for thyristor=%.0f ms\" %(t1*1000))\n",

-      "print(\"conduction time for diodes=%.0f ms\" %(t1*1000))\n",

-      "print(\"peak transistor current=%.2f A\" %I_p)\n",

-      "print(\"rms transistor current=%.2f A\" %I_t1)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "THD of voltage=0.4834\n",

-        "\n",

-        "DF=1.0\n",

-        "THD of current=0.1557\n",

-        "DF=0.988\n",

-        "load power=2313.5 W\n",

-        "avg value of load current=10.52 A\n",

-        "conduction time for thyristor=3 ms\n",

-        "conduction time for diodes=3 ms\n",

-        "peak transistor current=27.44 A\n",

-        "rms transistor current=12.66 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 8

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.11 Page No 497"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=450.0\n",

-      "R=10.0\n",

-      "\n",

-      "#Calculations\n",

-      "I_or=math.sqrt((V_s/(3*R))**2*2/3+(2*V_s/(3*R))**2*1/3)    \n",

-      "I_T1=math.sqrt((1/(2*math.pi))*((V_s/(3*R))**2*2*math.pi/3+(2*V_s/(3*R))**2*math.pi/3))   \n",

-      "P=3*I_or**2*R    \n",

-      "I_or=math.sqrt((1/(math.pi))*((V_s/(2*R))**2*2*math.pi/3))    \n",

-      "I_T1=math.sqrt((1/(2*math.pi))*((V_s/(2*R))**2*2*math.pi/3))    \n",

-      "P=3*I_or**2*R    \n",

-      "\n",

-      "#Results\n",

-      "print(\"for 180deg mode\")\n",

-      "print(\"rms value of load current=%.3f A\" %I_or)\n",

-      "print(\"power delivered to load=%.1f kW\" %(P/1000))\n",

-      "print(\"rms value of load current=%.0f A\" %I_T1)\n",

-      "print(\"for 120deg mode\")\n",

-      "print(\"rms value of load current=%.3f A\" %I_or)\n",

-      "print(\"rms value of load current=%.2f A\" %I_T1)\n",

-      "print(\"power delivered to load=%.3f kW\" %(P/1000))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for 180deg mode\n",

-        "rms value of load current=18.371 A\n",

-        "power delivered to load=10.1 kW\n",

-        "rms value of load current=13 A\n",

-        "for 120deg mode\n",

-        "rms value of load current=18.371 A\n",

-        "rms value of load current=12.99 A\n",

-        "power delivered to load=10.125 kW\n"

-       ]

-      }

-     ],

-     "prompt_number": 9

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.12, Page No 510"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "R=10.0\n",

-      "f=50.0\n",

-      "w=2*math.pi*f\n",

-      "L=0.03\n",

-      "\n",

-      "#Calculations\n",

-      "X_L=w*L\n",

-      "V_or=math.sqrt(V_s**2*math.pi/math.pi)\n",

-      "V_01=4*V_s/(math.sqrt(2)*math.pi)\n",

-      "Z1=math.sqrt(R**2+(X_L)**2)\n",

-      "phi1=-math.degrees(math.atan((X_L)/R))\n",

-      "Z3=math.sqrt(R**2+(X_L*3)**2)\n",

-      "phi3=math.degrees(math.atan((X_L*3)/R))\n",

-      "Z5=math.sqrt(R**2+(X_L*5)**2)\n",

-      "phi5=math.degrees(math.atan((X_L*5)/R))\n",

-      "Z7=math.sqrt(R**2+(X_L*7)**2)\n",

-      "phi7=math.degrees(math.atan((X_L*7)/R))\n",

-      "I_m1=4*V_s/(math.sqrt(2)*Z1*math.pi)\n",

-      "I_m3=4*V_s/(math.sqrt(2)*3*Z3*math.pi)\n",

-      "I_m5=4*V_s/(math.sqrt(2)*5*Z5*math.pi)\n",

-      "I_m7=4*V_s/(math.sqrt(2)*7*Z7*math.pi)\n",

-      "I_m=math.sqrt(I_m1**2+I_m3**2+I_m5**2+I_m7**2)\n",

-      "P=I_m**2*R    \n",

-      "I_01=I_m1*math.sin(math.radians(45))\n",

-      "I_03=I_m3*math.sin(math.radians(3*45))\n",

-      "I_05=I_m5*math.sin(math.radians(5*45))\n",

-      "I_07=I_m7*math.sin(math.radians(7*45))\n",

-      "I_0=(I_01**2+I_03**2+I_05**2+I_07**2)\n",

-      "P=I_0*R    \n",

-      "g=(180-90)/3+45/2\n",

-      "I_01=2*I_m1*math.sin(math.radians(g))*math.sin(math.radians(45/2))\n",

-      "I_03=2*I_m3*math.sin(math.radians(g*3))*math.sin(math.radians(3*45/2))\n",

-      "I_05=2*I_m5*math.sin(math.radians(g*5))*math.sin(math.radians(5*45/2))\n",

-      "I_07=2*I_m7*math.sin(math.radians(g*7))*math.sin(math.radians(7*45/2))\n",

-      "I_0=(I_01**2+I_03**2+I_05**2+I_07**2)\n",

-      "P=I_0*R    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"using square wave o/p\")\n",

-      "print(\"power delivered=%.2f W\" %P)\n",

-      "print(\"using quasi-square wave o/p\")\n",

-      "print(\"power delivered=%.2f W\" %P)\n",

-      "print(\"using two symmitrical spaced pulses\")\n",

-      "print(\"power delivered=%.2f W\" %P)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "using square wave o/p\n",

-        "power delivered=845.87 W\n",

-        "using quasi-square wave o/p\n",

-        "power delivered=845.87 W\n",

-        "using two symmitrical spaced pulses\n",

-        "power delivered=845.87 W\n"

-       ]

-      }

-     ],

-     "prompt_number": 10

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.14, Page No 520"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "f=50.0\n",

-      "T=1/f\n",

-      "I=0.5\n",

-      "\n",

-      "#Calculations\n",

-      "di=I/T     #di=di/dt\n",

-      "V_s=220.0\n",

-      "L=V_s/di    \n",

-      "t=20*10**-6\n",

-      "fos=2     #factor of safety\n",

-      "t_c=t*fos\n",

-      "R=10\n",

-      "C=t_c/(R*math.log(2))\n",

-      "\n",

-      "#Results    \n",

-      "print(\"source inductance=%.1f H\" %L)\n",

-      "print(\"commutating capacitor=%.2f uF\" %(C*10**6))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "source inductance=8.8 H\n",

-        "commutating capacitor=5.77 uF\n"

-       ]

-      }

-     ],

-     "prompt_number": 11

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.15, Page No 539"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "R=10.0\n",

-      "L=.01\n",

-      "C=10*10**-6\n",

-      "#Calculations\n",

-      "if (R**2)<(4*L/C) :\n",

-      "    print(\"ckt will commutate on its own\")\n",

-      "else:\n",

-      "    print(\"ckt will not commutate on its own\")\n",

-      "\n",

-      "xie=R/(2*L)\n",

-      "w_o=1/math.sqrt(L*C)\n",

-      "w_r=math.sqrt(w_o**2-xie**2)\n",

-      "phi=math.degrees(math.atan(xie/w_r))\n",

-      "t=math.pi/w_r\n",

-      "V_s=1\n",

-      "v_L=V_s*(w_o/w_r)*math.exp(-xie*t)*math.cos(math.radians(180+phi))\n",

-      "v_c=V_s*(1-(w_o/w_r)*math.exp(-xie*t)*math.cos(math.radians(180-phi)))   \n",

-      "di=V_s/L    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"voltage across inductor(*V_s)=%.5f V\" %v_L) \n",

-      "print(\"voltage across capacitor(*V_s)=%.5f V\" %v_c)\n",

-      "print(\"di/dt*V_s (for t=0)=%.0f A/s\" %di)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "ckt will commutate on its own\n",

-        "voltage across inductor(*V_s)=-0.60468 V\n",

-        "voltage across capacitor(*V_s)=1.60468 V\n",

-        "di/dt*V_s (for t=0)=100 A/s\n"

-       ]

-      }

-     ],

-     "prompt_number": 12

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.16, Page No 540"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "L=0.006\n",

-      "C=1.2*10**-6\n",

-      "R=100.0\n",

-      "\n",

-      "#Calculations\n",

-      "T=math.pi/math.sqrt(1/(L*C)-(R/(2*L))**2)\n",

-      "T_off=0.2*10**-3\n",

-      "f=1/(2*(T+T_off))    \n",

-      "R=40\n",

-      "T=math.pi/math.sqrt(1/(L*C)-(R/(2*L))**2)\n",

-      "T_off=.2*10**-3\n",

-      "f=1/(2*(T+T_off))    \n",

-      "R=140\n",

-      "T=math.pi/math.sqrt(1/(L*C)-(R/(2*L))**2)\n",

-      "T_off=.2*10**-3\n",

-      "f=1/(2*(T+T_off)) \n",

-      "\n",

-      "#Results\n",

-      "print(\"o/p freq=%.2f Hz\" %f)\n",

-      "print(\"for R=40ohm\")\n",

-      "print(\"upper limit o/p freq=%.1f Hz\" %f)\n",

-      "print(\"for R=140ohm\")\n",

-      "print(\"lower limit o/p freq=%.1f Hz\" %f)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "o/p freq=239.81 Hz\n",

-        "for R=40ohm\n",

-        "upper limit o/p freq=239.8 Hz\n",

-        "for R=140ohm\n",

-        "lower limit o/p freq=239.8 Hz\n"

-       ]

-      }

-     ],

-     "prompt_number": 13

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.17, Page No 540"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "f=5000.0\n",

-      "w=2*math.pi*f\n",

-      "R=3.0\n",

-      "\n",

-      "#Calculations\n",

-      "L=60*10**-6\n",

-      "xie=R/(2*L)\n",

-      "C=7.5*10**-6\n",

-      "w_o=1/math.sqrt(L*C)\n",

-      "w_r=math.sqrt(w_o**2-xie**2)\n",

-      "t_c=math.pi*(1/w-1/w_r)    \n",

-      "fos=1.5\n",

-      "t_q=10*10**-6\n",

-      "f_max=1/(2*math.pi*(t_q*fos/math.pi+1/w_r))    \n",

-      "\n",

-      "#Results\n",

-      "print(\"ckt turn off time=%.2f us\" %(t_c*10**6))\n",

-      "print(\"max possible operating freq=%.1f Hz\" %f_max)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "ckt turn off time=21.39 us\n",

-        "max possible operating freq=5341.4 Hz\n"

-       ]

-      }

-     ],

-     "prompt_number": 14

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.18, Page No 541"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "a=30.0\n",

-      "R=10.0\n",

-      "P=5000.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_s=math.sqrt(P*R*2*math.pi/(2*3)/(math.pi/3+math.sqrt(3)*math.cos(math.radians(2*a))/2))\n",

-      "V_ph=V_s/math.sqrt(3)    \n",

-      "I_or=math.sqrt(P*R)\n",

-      "V_s=I_or*math.pi/(math.sqrt(2)*3*math.cos(math.radians(a)))\n",

-      "V_ph=V_s/math.sqrt(3) \n",

-      "\n",

-      "#Results\n",

-      "print(\"per phase voltage  V_ph=%.3f V\" %V_ph)   \n",

-      "print(\"for constant load current\")\n",

-      "print(\"V_ph=%.2f V\" %V_ph)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "per phase voltage  V_ph=110.384 V\n",

-        "for constant load current\n",

-        "V_ph=110.38 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 15

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.19, Page No 547"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "t=20.0\n",

-      "fos=2.0     #factor of safety\n",

-      "\n",

-      "#Calculations\n",

-      "t_c=t*fos\n",

-      "n=1.0/3\n",

-      "R=20.0\n",

-      "C=n**2*t_c/(4*R*math.log(2)) \n",

-      "\n",

-      "#Results   \n",

-      "print(\"value of capacitor=%.2f uF\" %C)\n",

-      " #printing mistake in the answer in book."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "value of capacitor=0.08 uF\n"

-       ]

-      }

-     ],

-     "prompt_number": 16

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.20, Page No 547"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=220.0\n",

-      "V_p=math.sqrt(2)*V_s/3    \n",

-      "V_L=math.sqrt(3)*V_p    \n",

-      "V_p1=math.sqrt(2)*V_s/math.pi    \n",

-      "V_L1=math.sqrt(3)*V_p1    \n",

-      "V_oh=math.sqrt(V_L**2-V_L1**2)\n",

-      "\n",

-      "#Calculations\n",

-      "THD=V_oh/V_L1    \n",

-      "V_a1=2*V_s/math.pi\n",

-      "V_a5=2*V_s/(5*math.pi)\n",

-      "V_a7=2*V_s/(7*math.pi)\n",

-      "V_a11=2*V_s/(11*math.pi)\n",

-      "R=4.0\n",

-      "L=0.02\n",

-      "f=50\n",

-      "w=2*math.pi*f\n",

-      "Z1=math.sqrt(R**2+(w*L)**2)\n",

-      "Z5=math.sqrt(R**2+(5*w*L)**2)\n",

-      "Z7=math.sqrt(R**2+(7*w*L)**2)\n",

-      "Z11=math.sqrt(R**2+(11*w*L)**2)\n",

-      "I_a1=V_a1/Z1\n",

-      "I_a5=V_a5/Z5\n",

-      "I_a7=V_a7/Z7\n",

-      "I_a11=V_a11/Z11\n",

-      "I_or=math.sqrt((I_a1**2+I_a5**2+I_a7**2+I_a11**2)/2)\n",

-      "P=3*I_or**2*R    \n",

-      "I_s=P/V_s    \n",

-      "I_TA=I_s/3   \n",

-      " \n",

-      "#Results\n",

-      "print(\"rms value of phasor voltages=%.2f V\" %V_p)\n",

-      "print(\"rms value of line voltages=%.2f V\" %V_L)\n",

-      "print(\"fundamental component of phase voltage=%.3f V\" %V_p1)\n",

-      "print(\"fundamental component of line voltages=%.3f V\" %V_L1)\n",

-      "print(\"THD=%.7f\" %THD)\n",

-      "print(\"load power=%.1f W\" %P)\n",

-      "print(\"avg value of source current=%.3f A\" %I_s)\n",

-      "print(\"avg value of thyristor current=%.3f A\" %I_TA)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rms value of phasor voltages=103.71 V\n",

-        "rms value of line voltages=179.63 V\n",

-        "fundamental component of phase voltage=99.035 V\n",

-        "fundamental component of line voltages=171.533 V\n",

-        "THD=0.3108419\n",

-        "load power=2127.6 W\n",

-        "avg value of source current=9.671 A\n",

-        "avg value of thyristor current=3.224 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 17

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Power_Electronics/Chapter8_2.ipynb b/_Power_Electronics/Chapter8_2.ipynb
deleted file mode 100755
index 721a9faf..00000000
--- a/_Power_Electronics/Chapter8_2.ipynb
+++ /dev/null
@@ -1,984 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 08 : Inverters"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.3, Page No 465"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "T=0.1*10**-3\n",

-      "f=1.0/T\n",

-      "k=15*10**-6 #k=th/w\n",

-      "\n",

-      "#Calculations\n",

-      "th=2*math.pi*f*k\n",

-      "X_l=10.0\n",

-      "R=2.0\n",

-      "X_c=R*math.tan(th)+X_l\n",

-      "C=1/(2*math.pi*f*X_c)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"value of C=%.3f uF\" %(C*10**6))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "value of C=1.248 uF\n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.4 Page No 466"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_01=2*V_s/(math.sqrt(2)*math.pi)\n",

-      "R=2.0\n",

-      "I_01=V_01/R\n",

-      "P_d=I_01**2*R    \n",

-      "V=V_s/2\n",

-      "I_s=math.sqrt(2)*I_01/math.pi\n",

-      "P_s=V*I_s\n",

-      "\n",

-      "#Results\n",

-      "print(\"power delivered to load=%.1f W\" %P_d)\n",

-      "print(\"power delivered by both sources=%.1f W\" %(2*P_s))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "power delivered to load=5359.9 W\n",

-        "power delivered by both sources=5359.9 W\n"

-       ]

-      }

-     ],

-     "prompt_number": 2

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.5, Page No 468"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "V_01=4*V_s/(math.pi*math.sqrt(2))\n",

-      "R=1.0\n",

-      "X_L=6.0\n",

-      "X_c=7.0\n",

-      "\n",

-      "#Calculations\n",

-      "I_01=V_01/math.sqrt(R**2+(X_L-X_c)**2)\n",

-      "P=I_01**2*R    \n",

-      "I_s=math.sqrt(2)*I_01*(2*math.cos(math.radians(45)))/math.pi\n",

-      "P_s=V_s*I_s    \n",

-      "\n",

-      "#Results\n",

-      "print(\"power delivered to the source=%.3f kW\" %(P/1000))\n",

-      "print(\"\\npower from the source=%.3f kW\" %(P_s/1000))\n",

-      "   "

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "power delivered to the source=21.440 kW\n",

-        "\n",

-        "power from the source=21.440 kW\n"

-       ]

-      }

-     ],

-     "prompt_number": 3

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.6 Page No 469"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_01=230.0\n",

-      "R=2.0\n",

-      "I_01=V_01/R\n",

-      "I_m=I_01*math.sqrt(2)\n",

-      "I_T1=I_m/2    \n",

-      "I_D1=0    \n",

-      "X_L=8.0\n",

-      "X_C=6.0\n",

-      "\n",

-      "#Calculations\n",

-      "I_01=V_01/math.sqrt(R**2+(X_L-X_C)**2)\n",

-      "phi1=math.degrees(math.atan((X_L-X_C)/R))\n",

-      "I_T1=I_T1*math.sqrt(2)*0.47675    \n",

-      "I_D1=.1507025*I_m/math.sqrt(2)    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"when load R=2 ohm\")\n",

-      "print(\"rms value of thyristor current=%.2f A\" %I_T1)\n",

-      "print(\"rms value of diode current=%.0f A\" %I_D1)\n",

-      "print(\"when load R=2ohm % X_L=8ohm and X_C=6ohm\")\n",

-      "print(\"rms value of thyristor current=%.3f A\" %I_T1)\n",

-      "print(\"rms value of diode current=%.3f A\" %I_D1)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "when load R=2 ohm\n",

-        "rms value of thyristor current=54.83 A\n",

-        "rms value of diode current=17 A\n",

-        "when load R=2ohm % X_L=8ohm and X_C=6ohm\n",

-        "rms value of thyristor current=54.826 A\n",

-        "rms value of diode current=17.331 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 4

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.7 Page No 470"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "R=4.0\n",

-      "f=50.0\n",

-      "w=2*math.pi*f\n",

-      "L=0.035\n",

-      "\n",

-      "#Calculations\n",

-      "C=155*10**-6\n",

-      "X_L=w*L\n",

-      "X_C=1/(w*C)\n",

-      "Z1=math.sqrt(R**2+(X_L-X_C)**2)\n",

-      "phi1=-math.degrees(math.atan((X_L-X_C)/R))\n",

-      "Z3=math.sqrt(R**2+(X_L*3-X_C/3)**2)\n",

-      "phi3=math.degrees(math.atan((X_L*3-X_C/3)/R))\n",

-      "Z5=math.sqrt(R**2+(X_L*5-X_C/5)**2)\n",

-      "phi5=math.degrees(math.atan((X_L*5-X_C/5)/R))\n",

-      "I_m1=4*V_s/(Z1*math.pi)\n",

-      "I_01=I_m1/math.sqrt(2)    \n",

-      "I_m3=4*V_s/(3*Z3*math.pi)\n",

-      "I_m5=4*V_s/(5*Z5*math.pi)\n",

-      "I_m=math.sqrt(I_m1**2+I_m3**2+I_m5**2)\n",

-      "I_0=I_m/math.sqrt(2)\n",

-      "P_0=(I_0)**2*R    \n",

-      "P_01=(I_01)**2*R    \n",

-      "t1=(180-phi1)*math.pi/(180*w)    \n",

-      "t1=(phi1)*math.pi/(180*w)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"rms value of fundamental load current=%.2f A\" %I_01)\n",

-      "print(\"load power=%.1f W\" %P_0)\n",

-      "print(\"fundamental load power=%.1f W\" %P_01)\n",

-      "print(\"rms value of thyristor current=%.3f A\" %(I_m/2))\n",

-      "print(\"conduction time for thyristor=%.3f ms\" %(t1*1000))\n",

-      "print(\"Conduction time for diodes=%.3f ms\" %(t1*1000))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rms value of fundamental load current=20.02 A\n",

-        "load power=1632.5 W\n",

-        "fundamental load power=1602.6 W\n",

-        "rms value of thyristor current=14.285 A\n",

-        "conduction time for thyristor=3.736 ms\n",

-        "Conduction time for diodes=3.736 ms\n"

-       ]

-      }

-     ],

-     "prompt_number": 5

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.8, Page No 473"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "V_01=2*V_s/(math.sqrt(2)*math.pi)    \n",

-      "R=10.0\n",

-      "\n",

-      "#Calculations\n",

-      "I_01=V_01/R\n",

-      "P=I_01**2*R    \n",

-      "V_or=math.sqrt((V_s/2)**2)\n",

-      "P=V_or**2/R    \n",

-      "I_TP=V_s/(2*R)\n",

-      "I_or=I_TP\n",

-      "pf=I_01**2*R/(V_or*I_or)  \n",

-      "DF=V_01/V_or  \n",

-      "V_oh=math.sqrt(V_or**2-V_01**2)\n",

-      "THD=V_oh/V_01 \n",

-      "V_03=V_01/3\n",

-      "HF=V_03/V_01\n",

-      "\n",

-      "#Results\n",

-      "print(\"fundamental rms o/p voltage=%.3f V\" %V_01)\n",

-      "print(\"fundamental power to load=%.1f W\" %P)\n",

-      "print(\"total o/p power to load=%.1f W\" %P)\n",

-      "print(\"avg SCR current=%.2f A\" %(I_TP*180/360))\n",

-      "print(\"i/p pf=%.3f\" %pf)  \n",

-      "print(\"distortion factor=%.1f\" %DF)\n",

-      "print(\"THD=%.3f\" %THD)    \n",

-      "print(\"harmonic factor=%.4f\" %HF)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "fundamental rms o/p voltage=103.536 V\n",

-        "fundamental power to load=1322.5 W\n",

-        "total o/p power to load=1322.5 W\n",

-        "avg SCR current=5.75 A\n",

-        "i/p pf=0.811\n",

-        "distortion factor=0.9\n",

-        "THD=0.483\n",

-        "harmonic factor=0.3333\n"

-       ]

-      }

-     ],

-     "prompt_number": 6

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.9 Page No 474"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=60\n",

-      "R=3.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_or=math.sqrt(V_s**2*math.pi/math.pi)    \n",

-      "V_01=4*V_s/(math.sqrt(2)*math.pi)    \n",

-      "P_o=V_or**2/R    \n",

-      "P_01=V_01**2/R    \n",

-      "I_s=V_s/R    \n",

-      "I_avg=I_s*math.pi/(2*math.pi)    \n",

-      "V_03=V_01/3\n",

-      "HF=V_03/V_01    \n",

-      "V_oh=math.sqrt(V_or**2-V_01**2)\n",

-      "THD=V_oh/V_01   \n",

-      "\n",

-      "#Results\n",

-      "print(\"rms value of o/p voltage=%.0f V\" %V_or)\n",

-      "print(\"o/p power=%.0f W\" %P_o)\n",

-      "print(\"fundamental component of rms voltage=%.2f V\" %V_01)\n",

-      "print(\"fundamental freq o/p power=%.2f W\" %P_01) \n",

-      "print(\"peak current=%.0f A\" %I_s)\n",

-      "print(\"avg current of each transistor=%.0f A\" %I_avg)\n",

-      "print(\"peak reverse blocking voltage=%.0f V\" %V_s)\n",

-      "print(\"harmonic factor=%.4f\" %HF)\n",

-      "print(\"THD=%.4f\" %THD)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rms value of o/p voltage=60 V\n",

-        "o/p power=1200 W\n",

-        "fundamental component of rms voltage=54.02 V\n",

-        "fundamental freq o/p power=972.68 W\n",

-        "peak current=20 A\n",

-        "avg current of each transistor=10 A\n",

-        "peak reverse blocking voltage=60 V\n",

-        "harmonic factor=0.3333\n",

-        "THD=0.4834\n"

-       ]

-      }

-     ],

-     "prompt_number": 7

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.10 Page No 475"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=220.0\n",

-      "R=6.0\n",

-      "f=50.0\n",

-      "w=2*math.pi*f\n",

-      "L=0.03\n",

-      "C=180*10**-6\n",

-      "X_L=w*L\n",

-      "X_C=1/(w*C)\n",

-      "\n",

-      "#Calculations\n",

-      "V_or=math.sqrt(V_s**2*math.pi/math.pi)\n",

-      "V_01=4*V_s/(math.sqrt(2)*math.pi)\n",

-      "V_oh=math.sqrt(V_or**2-V_01**2)\n",

-      "THD=V_oh/V_01    \n",

-      "print(\"THD of voltage=%.4f\" %THD)\n",

-      "DF=V_01/V_or    \n",

-      "Z1=math.sqrt(R**2+(X_L-X_C)**2)\n",

-      "phi1=-math.degrees(math.atan((X_L-X_C)/R))\n",

-      "Z3=math.sqrt(R**2+(X_L*3-X_C/3)**2)\n",

-      "phi3=math.degrees(math.atan((X_L*3-X_C/3)/R))\n",

-      "Z5=math.sqrt(R**2+(X_L*5-X_C/5)**2)\n",

-      "phi5=math.degrees(math.atan((X_L*5-X_C/5)/R))\n",

-      "Z7=math.sqrt(R**2+(X_L*7-X_C/7)**2)\n",

-      "phi7=math.degrees(math.atan((X_L*7-X_C/7)/R))\n",

-      "I_01=19.403\n",

-      "I_m1=4*V_s/(Z1*math.pi)\n",

-      "I_m3=4*V_s/(3*Z3*math.pi)\n",

-      "I_m5=4*V_s/(5*Z5*math.pi)\n",

-      "I_m7=4*V_s/(7*Z7*math.pi)\n",

-      "I_m=math.sqrt(I_m1**2+I_m3**2+I_m5**2+I_m7**2)\n",

-      "I_or=I_m/math.sqrt(2)\n",

-      "I_oh=math.sqrt((I_m**2-I_m1**2)/2)\n",

-      "THD=I_oh/I_01    \n",

-      "DF=I_01/I_or    \n",

-      "P_o=I_or**2*R    \n",

-      "I_avg=P_o/V_s    \n",

-      "t1=(180-phi1)*math.pi/(180*w)    \n",

-      "t1=1/(2*f)-t1    \n",

-      "I_p=I_m1    \n",

-      "I_t1=.46135*I_p \n",

-      "\n",

-      "#Results\n",

-      "print(\"\\nDF=%.1f\" %DF)\n",

-      "print(\"THD of current=%.4f\" %THD)   \n",

-      "print(\"DF=%.3f\" %DF)\n",

-      "print(\"load power=%.1f W\" %P_o)\n",

-      "print(\"avg value of load current=%.2f A\" %I_avg)\n",

-      "print(\"conduction time for thyristor=%.0f ms\" %(t1*1000))\n",

-      "print(\"conduction time for diodes=%.0f ms\" %(t1*1000))\n",

-      "print(\"peak transistor current=%.2f A\" %I_p)\n",

-      "print(\"rms transistor current=%.2f A\" %I_t1)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "THD of voltage=0.4834\n",

-        "\n",

-        "DF=1.0\n",

-        "THD of current=0.1557\n",

-        "DF=0.988\n",

-        "load power=2313.5 W\n",

-        "avg value of load current=10.52 A\n",

-        "conduction time for thyristor=3 ms\n",

-        "conduction time for diodes=3 ms\n",

-        "peak transistor current=27.44 A\n",

-        "rms transistor current=12.66 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 8

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.11 Page No 497"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=450.0\n",

-      "R=10.0\n",

-      "\n",

-      "#Calculations\n",

-      "I_or=math.sqrt((V_s/(3*R))**2*2/3+(2*V_s/(3*R))**2*1/3)    \n",

-      "I_T1=math.sqrt((1/(2*math.pi))*((V_s/(3*R))**2*2*math.pi/3+(2*V_s/(3*R))**2*math.pi/3))   \n",

-      "P=3*I_or**2*R    \n",

-      "I_or=math.sqrt((1/(math.pi))*((V_s/(2*R))**2*2*math.pi/3))    \n",

-      "I_T1=math.sqrt((1/(2*math.pi))*((V_s/(2*R))**2*2*math.pi/3))    \n",

-      "P=3*I_or**2*R    \n",

-      "\n",

-      "#Results\n",

-      "print(\"for 180deg mode\")\n",

-      "print(\"rms value of load current=%.3f A\" %I_or)\n",

-      "print(\"power delivered to load=%.1f kW\" %(P/1000))\n",

-      "print(\"rms value of load current=%.0f A\" %I_T1)\n",

-      "print(\"for 120deg mode\")\n",

-      "print(\"rms value of load current=%.3f A\" %I_or)\n",

-      "print(\"rms value of load current=%.2f A\" %I_T1)\n",

-      "print(\"power delivered to load=%.3f kW\" %(P/1000))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for 180deg mode\n",

-        "rms value of load current=18.371 A\n",

-        "power delivered to load=10.1 kW\n",

-        "rms value of load current=13 A\n",

-        "for 120deg mode\n",

-        "rms value of load current=18.371 A\n",

-        "rms value of load current=12.99 A\n",

-        "power delivered to load=10.125 kW\n"

-       ]

-      }

-     ],

-     "prompt_number": 9

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.12, Page No 510"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "R=10.0\n",

-      "f=50.0\n",

-      "w=2*math.pi*f\n",

-      "L=0.03\n",

-      "\n",

-      "#Calculations\n",

-      "X_L=w*L\n",

-      "V_or=math.sqrt(V_s**2*math.pi/math.pi)\n",

-      "V_01=4*V_s/(math.sqrt(2)*math.pi)\n",

-      "Z1=math.sqrt(R**2+(X_L)**2)\n",

-      "phi1=-math.degrees(math.atan((X_L)/R))\n",

-      "Z3=math.sqrt(R**2+(X_L*3)**2)\n",

-      "phi3=math.degrees(math.atan((X_L*3)/R))\n",

-      "Z5=math.sqrt(R**2+(X_L*5)**2)\n",

-      "phi5=math.degrees(math.atan((X_L*5)/R))\n",

-      "Z7=math.sqrt(R**2+(X_L*7)**2)\n",

-      "phi7=math.degrees(math.atan((X_L*7)/R))\n",

-      "I_m1=4*V_s/(math.sqrt(2)*Z1*math.pi)\n",

-      "I_m3=4*V_s/(math.sqrt(2)*3*Z3*math.pi)\n",

-      "I_m5=4*V_s/(math.sqrt(2)*5*Z5*math.pi)\n",

-      "I_m7=4*V_s/(math.sqrt(2)*7*Z7*math.pi)\n",

-      "I_m=math.sqrt(I_m1**2+I_m3**2+I_m5**2+I_m7**2)\n",

-      "P=I_m**2*R    \n",

-      "I_01=I_m1*math.sin(math.radians(45))\n",

-      "I_03=I_m3*math.sin(math.radians(3*45))\n",

-      "I_05=I_m5*math.sin(math.radians(5*45))\n",

-      "I_07=I_m7*math.sin(math.radians(7*45))\n",

-      "I_0=(I_01**2+I_03**2+I_05**2+I_07**2)\n",

-      "P=I_0*R    \n",

-      "g=(180-90)/3+45/2\n",

-      "I_01=2*I_m1*math.sin(math.radians(g))*math.sin(math.radians(45/2))\n",

-      "I_03=2*I_m3*math.sin(math.radians(g*3))*math.sin(math.radians(3*45/2))\n",

-      "I_05=2*I_m5*math.sin(math.radians(g*5))*math.sin(math.radians(5*45/2))\n",

-      "I_07=2*I_m7*math.sin(math.radians(g*7))*math.sin(math.radians(7*45/2))\n",

-      "I_0=(I_01**2+I_03**2+I_05**2+I_07**2)\n",

-      "P=I_0*R    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"using square wave o/p\")\n",

-      "print(\"power delivered=%.2f W\" %P)\n",

-      "print(\"using quasi-square wave o/p\")\n",

-      "print(\"power delivered=%.2f W\" %P)\n",

-      "print(\"using two symmitrical spaced pulses\")\n",

-      "print(\"power delivered=%.2f W\" %P)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "using square wave o/p\n",

-        "power delivered=845.87 W\n",

-        "using quasi-square wave o/p\n",

-        "power delivered=845.87 W\n",

-        "using two symmitrical spaced pulses\n",

-        "power delivered=845.87 W\n"

-       ]

-      }

-     ],

-     "prompt_number": 10

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.14, Page No 520"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "f=50.0\n",

-      "T=1/f\n",

-      "I=0.5\n",

-      "\n",

-      "#Calculations\n",

-      "di=I/T     #di=di/dt\n",

-      "V_s=220.0\n",

-      "L=V_s/di    \n",

-      "t=20*10**-6\n",

-      "fos=2     #factor of safety\n",

-      "t_c=t*fos\n",

-      "R=10\n",

-      "C=t_c/(R*math.log(2))\n",

-      "\n",

-      "#Results    \n",

-      "print(\"source inductance=%.1f H\" %L)\n",

-      "print(\"commutating capacitor=%.2f uF\" %(C*10**6))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "source inductance=8.8 H\n",

-        "commutating capacitor=5.77 uF\n"

-       ]

-      }

-     ],

-     "prompt_number": 11

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.15, Page No 539"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "R=10.0\n",

-      "L=.01\n",

-      "C=10*10**-6\n",

-      "#Calculations\n",

-      "if (R**2)<(4*L/C) :\n",

-      "    print(\"ckt will commutate on its own\")\n",

-      "else:\n",

-      "    print(\"ckt will not commutate on its own\")\n",

-      "\n",

-      "xie=R/(2*L)\n",

-      "w_o=1/math.sqrt(L*C)\n",

-      "w_r=math.sqrt(w_o**2-xie**2)\n",

-      "phi=math.degrees(math.atan(xie/w_r))\n",

-      "t=math.pi/w_r\n",

-      "V_s=1\n",

-      "v_L=V_s*(w_o/w_r)*math.exp(-xie*t)*math.cos(math.radians(180+phi))\n",

-      "v_c=V_s*(1-(w_o/w_r)*math.exp(-xie*t)*math.cos(math.radians(180-phi)))   \n",

-      "di=V_s/L    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"voltage across inductor(*V_s)=%.5f V\" %v_L) \n",

-      "print(\"voltage across capacitor(*V_s)=%.5f V\" %v_c)\n",

-      "print(\"di/dt*V_s (for t=0)=%.0f A/s\" %di)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "ckt will commutate on its own\n",

-        "voltage across inductor(*V_s)=-0.60468 V\n",

-        "voltage across capacitor(*V_s)=1.60468 V\n",

-        "di/dt*V_s (for t=0)=100 A/s\n"

-       ]

-      }

-     ],

-     "prompt_number": 12

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.16, Page No 540"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "L=0.006\n",

-      "C=1.2*10**-6\n",

-      "R=100.0\n",

-      "\n",

-      "#Calculations\n",

-      "T=math.pi/math.sqrt(1/(L*C)-(R/(2*L))**2)\n",

-      "T_off=0.2*10**-3\n",

-      "f=1/(2*(T+T_off))    \n",

-      "R=40\n",

-      "T=math.pi/math.sqrt(1/(L*C)-(R/(2*L))**2)\n",

-      "T_off=.2*10**-3\n",

-      "f=1/(2*(T+T_off))    \n",

-      "R=140\n",

-      "T=math.pi/math.sqrt(1/(L*C)-(R/(2*L))**2)\n",

-      "T_off=.2*10**-3\n",

-      "f=1/(2*(T+T_off)) \n",

-      "\n",

-      "#Results\n",

-      "print(\"o/p freq=%.2f Hz\" %f)\n",

-      "print(\"for R=40ohm\")\n",

-      "print(\"upper limit o/p freq=%.1f Hz\" %f)\n",

-      "print(\"for R=140ohm\")\n",

-      "print(\"lower limit o/p freq=%.1f Hz\" %f)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "o/p freq=239.81 Hz\n",

-        "for R=40ohm\n",

-        "upper limit o/p freq=239.8 Hz\n",

-        "for R=140ohm\n",

-        "lower limit o/p freq=239.8 Hz\n"

-       ]

-      }

-     ],

-     "prompt_number": 13

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.17, Page No 540"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "f=5000.0\n",

-      "w=2*math.pi*f\n",

-      "R=3.0\n",

-      "\n",

-      "#Calculations\n",

-      "L=60*10**-6\n",

-      "xie=R/(2*L)\n",

-      "C=7.5*10**-6\n",

-      "w_o=1/math.sqrt(L*C)\n",

-      "w_r=math.sqrt(w_o**2-xie**2)\n",

-      "t_c=math.pi*(1/w-1/w_r)    \n",

-      "fos=1.5\n",

-      "t_q=10*10**-6\n",

-      "f_max=1/(2*math.pi*(t_q*fos/math.pi+1/w_r))    \n",

-      "\n",

-      "#Results\n",

-      "print(\"ckt turn off time=%.2f us\" %(t_c*10**6))\n",

-      "print(\"max possible operating freq=%.1f Hz\" %f_max)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "ckt turn off time=21.39 us\n",

-        "max possible operating freq=5341.4 Hz\n"

-       ]

-      }

-     ],

-     "prompt_number": 14

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.18, Page No 541"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "a=30.0\n",

-      "R=10.0\n",

-      "P=5000.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_s=math.sqrt(P*R*2*math.pi/(2*3)/(math.pi/3+math.sqrt(3)*math.cos(math.radians(2*a))/2))\n",

-      "V_ph=V_s/math.sqrt(3)    \n",

-      "I_or=math.sqrt(P*R)\n",

-      "V_s=I_or*math.pi/(math.sqrt(2)*3*math.cos(math.radians(a)))\n",

-      "V_ph=V_s/math.sqrt(3) \n",

-      "\n",

-      "#Results\n",

-      "print(\"per phase voltage  V_ph=%.3f V\" %V_ph)   \n",

-      "print(\"for constant load current\")\n",

-      "print(\"V_ph=%.2f V\" %V_ph)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "per phase voltage  V_ph=110.384 V\n",

-        "for constant load current\n",

-        "V_ph=110.38 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 15

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.19, Page No 547"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "t=20.0\n",

-      "fos=2.0     #factor of safety\n",

-      "\n",

-      "#Calculations\n",

-      "t_c=t*fos\n",

-      "n=1.0/3\n",

-      "R=20.0\n",

-      "C=n**2*t_c/(4*R*math.log(2)) \n",

-      "\n",

-      "#Results   \n",

-      "print(\"value of capacitor=%.2f uF\" %C)\n",

-      " #printing mistake in the answer in book."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "value of capacitor=0.08 uF\n"

-       ]

-      }

-     ],

-     "prompt_number": 16

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.20, Page No 547"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=220.0\n",

-      "V_p=math.sqrt(2)*V_s/3    \n",

-      "V_L=math.sqrt(3)*V_p    \n",

-      "V_p1=math.sqrt(2)*V_s/math.pi    \n",

-      "V_L1=math.sqrt(3)*V_p1    \n",

-      "V_oh=math.sqrt(V_L**2-V_L1**2)\n",

-      "\n",

-      "#Calculations\n",

-      "THD=V_oh/V_L1    \n",

-      "V_a1=2*V_s/math.pi\n",

-      "V_a5=2*V_s/(5*math.pi)\n",

-      "V_a7=2*V_s/(7*math.pi)\n",

-      "V_a11=2*V_s/(11*math.pi)\n",

-      "R=4.0\n",

-      "L=0.02\n",

-      "f=50\n",

-      "w=2*math.pi*f\n",

-      "Z1=math.sqrt(R**2+(w*L)**2)\n",

-      "Z5=math.sqrt(R**2+(5*w*L)**2)\n",

-      "Z7=math.sqrt(R**2+(7*w*L)**2)\n",

-      "Z11=math.sqrt(R**2+(11*w*L)**2)\n",

-      "I_a1=V_a1/Z1\n",

-      "I_a5=V_a5/Z5\n",

-      "I_a7=V_a7/Z7\n",

-      "I_a11=V_a11/Z11\n",

-      "I_or=math.sqrt((I_a1**2+I_a5**2+I_a7**2+I_a11**2)/2)\n",

-      "P=3*I_or**2*R    \n",

-      "I_s=P/V_s    \n",

-      "I_TA=I_s/3   \n",

-      " \n",

-      "#Results\n",

-      "print(\"rms value of phasor voltages=%.2f V\" %V_p)\n",

-      "print(\"rms value of line voltages=%.2f V\" %V_L)\n",

-      "print(\"fundamental component of phase voltage=%.3f V\" %V_p1)\n",

-      "print(\"fundamental component of line voltages=%.3f V\" %V_L1)\n",

-      "print(\"THD=%.7f\" %THD)\n",

-      "print(\"load power=%.1f W\" %P)\n",

-      "print(\"avg value of source current=%.3f A\" %I_s)\n",

-      "print(\"avg value of thyristor current=%.3f A\" %I_TA)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rms value of phasor voltages=103.71 V\n",

-        "rms value of line voltages=179.63 V\n",

-        "fundamental component of phase voltage=99.035 V\n",

-        "fundamental component of line voltages=171.533 V\n",

-        "THD=0.3108419\n",

-        "load power=2127.6 W\n",

-        "avg value of source current=9.671 A\n",

-        "avg value of thyristor current=3.224 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 17

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Power_Electronics/Chapter8_3.ipynb b/_Power_Electronics/Chapter8_3.ipynb
deleted file mode 100755
index 721a9faf..00000000
--- a/_Power_Electronics/Chapter8_3.ipynb
+++ /dev/null
@@ -1,984 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 08 : Inverters"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.3, Page No 465"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "T=0.1*10**-3\n",

-      "f=1.0/T\n",

-      "k=15*10**-6 #k=th/w\n",

-      "\n",

-      "#Calculations\n",

-      "th=2*math.pi*f*k\n",

-      "X_l=10.0\n",

-      "R=2.0\n",

-      "X_c=R*math.tan(th)+X_l\n",

-      "C=1/(2*math.pi*f*X_c)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"value of C=%.3f uF\" %(C*10**6))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "value of C=1.248 uF\n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.4 Page No 466"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_01=2*V_s/(math.sqrt(2)*math.pi)\n",

-      "R=2.0\n",

-      "I_01=V_01/R\n",

-      "P_d=I_01**2*R    \n",

-      "V=V_s/2\n",

-      "I_s=math.sqrt(2)*I_01/math.pi\n",

-      "P_s=V*I_s\n",

-      "\n",

-      "#Results\n",

-      "print(\"power delivered to load=%.1f W\" %P_d)\n",

-      "print(\"power delivered by both sources=%.1f W\" %(2*P_s))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "power delivered to load=5359.9 W\n",

-        "power delivered by both sources=5359.9 W\n"

-       ]

-      }

-     ],

-     "prompt_number": 2

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.5, Page No 468"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "V_01=4*V_s/(math.pi*math.sqrt(2))\n",

-      "R=1.0\n",

-      "X_L=6.0\n",

-      "X_c=7.0\n",

-      "\n",

-      "#Calculations\n",

-      "I_01=V_01/math.sqrt(R**2+(X_L-X_c)**2)\n",

-      "P=I_01**2*R    \n",

-      "I_s=math.sqrt(2)*I_01*(2*math.cos(math.radians(45)))/math.pi\n",

-      "P_s=V_s*I_s    \n",

-      "\n",

-      "#Results\n",

-      "print(\"power delivered to the source=%.3f kW\" %(P/1000))\n",

-      "print(\"\\npower from the source=%.3f kW\" %(P_s/1000))\n",

-      "   "

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "power delivered to the source=21.440 kW\n",

-        "\n",

-        "power from the source=21.440 kW\n"

-       ]

-      }

-     ],

-     "prompt_number": 3

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.6 Page No 469"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_01=230.0\n",

-      "R=2.0\n",

-      "I_01=V_01/R\n",

-      "I_m=I_01*math.sqrt(2)\n",

-      "I_T1=I_m/2    \n",

-      "I_D1=0    \n",

-      "X_L=8.0\n",

-      "X_C=6.0\n",

-      "\n",

-      "#Calculations\n",

-      "I_01=V_01/math.sqrt(R**2+(X_L-X_C)**2)\n",

-      "phi1=math.degrees(math.atan((X_L-X_C)/R))\n",

-      "I_T1=I_T1*math.sqrt(2)*0.47675    \n",

-      "I_D1=.1507025*I_m/math.sqrt(2)    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"when load R=2 ohm\")\n",

-      "print(\"rms value of thyristor current=%.2f A\" %I_T1)\n",

-      "print(\"rms value of diode current=%.0f A\" %I_D1)\n",

-      "print(\"when load R=2ohm % X_L=8ohm and X_C=6ohm\")\n",

-      "print(\"rms value of thyristor current=%.3f A\" %I_T1)\n",

-      "print(\"rms value of diode current=%.3f A\" %I_D1)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "when load R=2 ohm\n",

-        "rms value of thyristor current=54.83 A\n",

-        "rms value of diode current=17 A\n",

-        "when load R=2ohm % X_L=8ohm and X_C=6ohm\n",

-        "rms value of thyristor current=54.826 A\n",

-        "rms value of diode current=17.331 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 4

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.7 Page No 470"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "R=4.0\n",

-      "f=50.0\n",

-      "w=2*math.pi*f\n",

-      "L=0.035\n",

-      "\n",

-      "#Calculations\n",

-      "C=155*10**-6\n",

-      "X_L=w*L\n",

-      "X_C=1/(w*C)\n",

-      "Z1=math.sqrt(R**2+(X_L-X_C)**2)\n",

-      "phi1=-math.degrees(math.atan((X_L-X_C)/R))\n",

-      "Z3=math.sqrt(R**2+(X_L*3-X_C/3)**2)\n",

-      "phi3=math.degrees(math.atan((X_L*3-X_C/3)/R))\n",

-      "Z5=math.sqrt(R**2+(X_L*5-X_C/5)**2)\n",

-      "phi5=math.degrees(math.atan((X_L*5-X_C/5)/R))\n",

-      "I_m1=4*V_s/(Z1*math.pi)\n",

-      "I_01=I_m1/math.sqrt(2)    \n",

-      "I_m3=4*V_s/(3*Z3*math.pi)\n",

-      "I_m5=4*V_s/(5*Z5*math.pi)\n",

-      "I_m=math.sqrt(I_m1**2+I_m3**2+I_m5**2)\n",

-      "I_0=I_m/math.sqrt(2)\n",

-      "P_0=(I_0)**2*R    \n",

-      "P_01=(I_01)**2*R    \n",

-      "t1=(180-phi1)*math.pi/(180*w)    \n",

-      "t1=(phi1)*math.pi/(180*w)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"rms value of fundamental load current=%.2f A\" %I_01)\n",

-      "print(\"load power=%.1f W\" %P_0)\n",

-      "print(\"fundamental load power=%.1f W\" %P_01)\n",

-      "print(\"rms value of thyristor current=%.3f A\" %(I_m/2))\n",

-      "print(\"conduction time for thyristor=%.3f ms\" %(t1*1000))\n",

-      "print(\"Conduction time for diodes=%.3f ms\" %(t1*1000))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rms value of fundamental load current=20.02 A\n",

-        "load power=1632.5 W\n",

-        "fundamental load power=1602.6 W\n",

-        "rms value of thyristor current=14.285 A\n",

-        "conduction time for thyristor=3.736 ms\n",

-        "Conduction time for diodes=3.736 ms\n"

-       ]

-      }

-     ],

-     "prompt_number": 5

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.8, Page No 473"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "V_01=2*V_s/(math.sqrt(2)*math.pi)    \n",

-      "R=10.0\n",

-      "\n",

-      "#Calculations\n",

-      "I_01=V_01/R\n",

-      "P=I_01**2*R    \n",

-      "V_or=math.sqrt((V_s/2)**2)\n",

-      "P=V_or**2/R    \n",

-      "I_TP=V_s/(2*R)\n",

-      "I_or=I_TP\n",

-      "pf=I_01**2*R/(V_or*I_or)  \n",

-      "DF=V_01/V_or  \n",

-      "V_oh=math.sqrt(V_or**2-V_01**2)\n",

-      "THD=V_oh/V_01 \n",

-      "V_03=V_01/3\n",

-      "HF=V_03/V_01\n",

-      "\n",

-      "#Results\n",

-      "print(\"fundamental rms o/p voltage=%.3f V\" %V_01)\n",

-      "print(\"fundamental power to load=%.1f W\" %P)\n",

-      "print(\"total o/p power to load=%.1f W\" %P)\n",

-      "print(\"avg SCR current=%.2f A\" %(I_TP*180/360))\n",

-      "print(\"i/p pf=%.3f\" %pf)  \n",

-      "print(\"distortion factor=%.1f\" %DF)\n",

-      "print(\"THD=%.3f\" %THD)    \n",

-      "print(\"harmonic factor=%.4f\" %HF)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "fundamental rms o/p voltage=103.536 V\n",

-        "fundamental power to load=1322.5 W\n",

-        "total o/p power to load=1322.5 W\n",

-        "avg SCR current=5.75 A\n",

-        "i/p pf=0.811\n",

-        "distortion factor=0.9\n",

-        "THD=0.483\n",

-        "harmonic factor=0.3333\n"

-       ]

-      }

-     ],

-     "prompt_number": 6

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.9 Page No 474"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=60\n",

-      "R=3.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_or=math.sqrt(V_s**2*math.pi/math.pi)    \n",

-      "V_01=4*V_s/(math.sqrt(2)*math.pi)    \n",

-      "P_o=V_or**2/R    \n",

-      "P_01=V_01**2/R    \n",

-      "I_s=V_s/R    \n",

-      "I_avg=I_s*math.pi/(2*math.pi)    \n",

-      "V_03=V_01/3\n",

-      "HF=V_03/V_01    \n",

-      "V_oh=math.sqrt(V_or**2-V_01**2)\n",

-      "THD=V_oh/V_01   \n",

-      "\n",

-      "#Results\n",

-      "print(\"rms value of o/p voltage=%.0f V\" %V_or)\n",

-      "print(\"o/p power=%.0f W\" %P_o)\n",

-      "print(\"fundamental component of rms voltage=%.2f V\" %V_01)\n",

-      "print(\"fundamental freq o/p power=%.2f W\" %P_01) \n",

-      "print(\"peak current=%.0f A\" %I_s)\n",

-      "print(\"avg current of each transistor=%.0f A\" %I_avg)\n",

-      "print(\"peak reverse blocking voltage=%.0f V\" %V_s)\n",

-      "print(\"harmonic factor=%.4f\" %HF)\n",

-      "print(\"THD=%.4f\" %THD)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rms value of o/p voltage=60 V\n",

-        "o/p power=1200 W\n",

-        "fundamental component of rms voltage=54.02 V\n",

-        "fundamental freq o/p power=972.68 W\n",

-        "peak current=20 A\n",

-        "avg current of each transistor=10 A\n",

-        "peak reverse blocking voltage=60 V\n",

-        "harmonic factor=0.3333\n",

-        "THD=0.4834\n"

-       ]

-      }

-     ],

-     "prompt_number": 7

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.10 Page No 475"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=220.0\n",

-      "R=6.0\n",

-      "f=50.0\n",

-      "w=2*math.pi*f\n",

-      "L=0.03\n",

-      "C=180*10**-6\n",

-      "X_L=w*L\n",

-      "X_C=1/(w*C)\n",

-      "\n",

-      "#Calculations\n",

-      "V_or=math.sqrt(V_s**2*math.pi/math.pi)\n",

-      "V_01=4*V_s/(math.sqrt(2)*math.pi)\n",

-      "V_oh=math.sqrt(V_or**2-V_01**2)\n",

-      "THD=V_oh/V_01    \n",

-      "print(\"THD of voltage=%.4f\" %THD)\n",

-      "DF=V_01/V_or    \n",

-      "Z1=math.sqrt(R**2+(X_L-X_C)**2)\n",

-      "phi1=-math.degrees(math.atan((X_L-X_C)/R))\n",

-      "Z3=math.sqrt(R**2+(X_L*3-X_C/3)**2)\n",

-      "phi3=math.degrees(math.atan((X_L*3-X_C/3)/R))\n",

-      "Z5=math.sqrt(R**2+(X_L*5-X_C/5)**2)\n",

-      "phi5=math.degrees(math.atan((X_L*5-X_C/5)/R))\n",

-      "Z7=math.sqrt(R**2+(X_L*7-X_C/7)**2)\n",

-      "phi7=math.degrees(math.atan((X_L*7-X_C/7)/R))\n",

-      "I_01=19.403\n",

-      "I_m1=4*V_s/(Z1*math.pi)\n",

-      "I_m3=4*V_s/(3*Z3*math.pi)\n",

-      "I_m5=4*V_s/(5*Z5*math.pi)\n",

-      "I_m7=4*V_s/(7*Z7*math.pi)\n",

-      "I_m=math.sqrt(I_m1**2+I_m3**2+I_m5**2+I_m7**2)\n",

-      "I_or=I_m/math.sqrt(2)\n",

-      "I_oh=math.sqrt((I_m**2-I_m1**2)/2)\n",

-      "THD=I_oh/I_01    \n",

-      "DF=I_01/I_or    \n",

-      "P_o=I_or**2*R    \n",

-      "I_avg=P_o/V_s    \n",

-      "t1=(180-phi1)*math.pi/(180*w)    \n",

-      "t1=1/(2*f)-t1    \n",

-      "I_p=I_m1    \n",

-      "I_t1=.46135*I_p \n",

-      "\n",

-      "#Results\n",

-      "print(\"\\nDF=%.1f\" %DF)\n",

-      "print(\"THD of current=%.4f\" %THD)   \n",

-      "print(\"DF=%.3f\" %DF)\n",

-      "print(\"load power=%.1f W\" %P_o)\n",

-      "print(\"avg value of load current=%.2f A\" %I_avg)\n",

-      "print(\"conduction time for thyristor=%.0f ms\" %(t1*1000))\n",

-      "print(\"conduction time for diodes=%.0f ms\" %(t1*1000))\n",

-      "print(\"peak transistor current=%.2f A\" %I_p)\n",

-      "print(\"rms transistor current=%.2f A\" %I_t1)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "THD of voltage=0.4834\n",

-        "\n",

-        "DF=1.0\n",

-        "THD of current=0.1557\n",

-        "DF=0.988\n",

-        "load power=2313.5 W\n",

-        "avg value of load current=10.52 A\n",

-        "conduction time for thyristor=3 ms\n",

-        "conduction time for diodes=3 ms\n",

-        "peak transistor current=27.44 A\n",

-        "rms transistor current=12.66 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 8

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.11 Page No 497"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=450.0\n",

-      "R=10.0\n",

-      "\n",

-      "#Calculations\n",

-      "I_or=math.sqrt((V_s/(3*R))**2*2/3+(2*V_s/(3*R))**2*1/3)    \n",

-      "I_T1=math.sqrt((1/(2*math.pi))*((V_s/(3*R))**2*2*math.pi/3+(2*V_s/(3*R))**2*math.pi/3))   \n",

-      "P=3*I_or**2*R    \n",

-      "I_or=math.sqrt((1/(math.pi))*((V_s/(2*R))**2*2*math.pi/3))    \n",

-      "I_T1=math.sqrt((1/(2*math.pi))*((V_s/(2*R))**2*2*math.pi/3))    \n",

-      "P=3*I_or**2*R    \n",

-      "\n",

-      "#Results\n",

-      "print(\"for 180deg mode\")\n",

-      "print(\"rms value of load current=%.3f A\" %I_or)\n",

-      "print(\"power delivered to load=%.1f kW\" %(P/1000))\n",

-      "print(\"rms value of load current=%.0f A\" %I_T1)\n",

-      "print(\"for 120deg mode\")\n",

-      "print(\"rms value of load current=%.3f A\" %I_or)\n",

-      "print(\"rms value of load current=%.2f A\" %I_T1)\n",

-      "print(\"power delivered to load=%.3f kW\" %(P/1000))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for 180deg mode\n",

-        "rms value of load current=18.371 A\n",

-        "power delivered to load=10.1 kW\n",

-        "rms value of load current=13 A\n",

-        "for 120deg mode\n",

-        "rms value of load current=18.371 A\n",

-        "rms value of load current=12.99 A\n",

-        "power delivered to load=10.125 kW\n"

-       ]

-      }

-     ],

-     "prompt_number": 9

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.12, Page No 510"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "R=10.0\n",

-      "f=50.0\n",

-      "w=2*math.pi*f\n",

-      "L=0.03\n",

-      "\n",

-      "#Calculations\n",

-      "X_L=w*L\n",

-      "V_or=math.sqrt(V_s**2*math.pi/math.pi)\n",

-      "V_01=4*V_s/(math.sqrt(2)*math.pi)\n",

-      "Z1=math.sqrt(R**2+(X_L)**2)\n",

-      "phi1=-math.degrees(math.atan((X_L)/R))\n",

-      "Z3=math.sqrt(R**2+(X_L*3)**2)\n",

-      "phi3=math.degrees(math.atan((X_L*3)/R))\n",

-      "Z5=math.sqrt(R**2+(X_L*5)**2)\n",

-      "phi5=math.degrees(math.atan((X_L*5)/R))\n",

-      "Z7=math.sqrt(R**2+(X_L*7)**2)\n",

-      "phi7=math.degrees(math.atan((X_L*7)/R))\n",

-      "I_m1=4*V_s/(math.sqrt(2)*Z1*math.pi)\n",

-      "I_m3=4*V_s/(math.sqrt(2)*3*Z3*math.pi)\n",

-      "I_m5=4*V_s/(math.sqrt(2)*5*Z5*math.pi)\n",

-      "I_m7=4*V_s/(math.sqrt(2)*7*Z7*math.pi)\n",

-      "I_m=math.sqrt(I_m1**2+I_m3**2+I_m5**2+I_m7**2)\n",

-      "P=I_m**2*R    \n",

-      "I_01=I_m1*math.sin(math.radians(45))\n",

-      "I_03=I_m3*math.sin(math.radians(3*45))\n",

-      "I_05=I_m5*math.sin(math.radians(5*45))\n",

-      "I_07=I_m7*math.sin(math.radians(7*45))\n",

-      "I_0=(I_01**2+I_03**2+I_05**2+I_07**2)\n",

-      "P=I_0*R    \n",

-      "g=(180-90)/3+45/2\n",

-      "I_01=2*I_m1*math.sin(math.radians(g))*math.sin(math.radians(45/2))\n",

-      "I_03=2*I_m3*math.sin(math.radians(g*3))*math.sin(math.radians(3*45/2))\n",

-      "I_05=2*I_m5*math.sin(math.radians(g*5))*math.sin(math.radians(5*45/2))\n",

-      "I_07=2*I_m7*math.sin(math.radians(g*7))*math.sin(math.radians(7*45/2))\n",

-      "I_0=(I_01**2+I_03**2+I_05**2+I_07**2)\n",

-      "P=I_0*R    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"using square wave o/p\")\n",

-      "print(\"power delivered=%.2f W\" %P)\n",

-      "print(\"using quasi-square wave o/p\")\n",

-      "print(\"power delivered=%.2f W\" %P)\n",

-      "print(\"using two symmitrical spaced pulses\")\n",

-      "print(\"power delivered=%.2f W\" %P)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "using square wave o/p\n",

-        "power delivered=845.87 W\n",

-        "using quasi-square wave o/p\n",

-        "power delivered=845.87 W\n",

-        "using two symmitrical spaced pulses\n",

-        "power delivered=845.87 W\n"

-       ]

-      }

-     ],

-     "prompt_number": 10

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.14, Page No 520"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "f=50.0\n",

-      "T=1/f\n",

-      "I=0.5\n",

-      "\n",

-      "#Calculations\n",

-      "di=I/T     #di=di/dt\n",

-      "V_s=220.0\n",

-      "L=V_s/di    \n",

-      "t=20*10**-6\n",

-      "fos=2     #factor of safety\n",

-      "t_c=t*fos\n",

-      "R=10\n",

-      "C=t_c/(R*math.log(2))\n",

-      "\n",

-      "#Results    \n",

-      "print(\"source inductance=%.1f H\" %L)\n",

-      "print(\"commutating capacitor=%.2f uF\" %(C*10**6))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "source inductance=8.8 H\n",

-        "commutating capacitor=5.77 uF\n"

-       ]

-      }

-     ],

-     "prompt_number": 11

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.15, Page No 539"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "R=10.0\n",

-      "L=.01\n",

-      "C=10*10**-6\n",

-      "#Calculations\n",

-      "if (R**2)<(4*L/C) :\n",

-      "    print(\"ckt will commutate on its own\")\n",

-      "else:\n",

-      "    print(\"ckt will not commutate on its own\")\n",

-      "\n",

-      "xie=R/(2*L)\n",

-      "w_o=1/math.sqrt(L*C)\n",

-      "w_r=math.sqrt(w_o**2-xie**2)\n",

-      "phi=math.degrees(math.atan(xie/w_r))\n",

-      "t=math.pi/w_r\n",

-      "V_s=1\n",

-      "v_L=V_s*(w_o/w_r)*math.exp(-xie*t)*math.cos(math.radians(180+phi))\n",

-      "v_c=V_s*(1-(w_o/w_r)*math.exp(-xie*t)*math.cos(math.radians(180-phi)))   \n",

-      "di=V_s/L    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"voltage across inductor(*V_s)=%.5f V\" %v_L) \n",

-      "print(\"voltage across capacitor(*V_s)=%.5f V\" %v_c)\n",

-      "print(\"di/dt*V_s (for t=0)=%.0f A/s\" %di)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "ckt will commutate on its own\n",

-        "voltage across inductor(*V_s)=-0.60468 V\n",

-        "voltage across capacitor(*V_s)=1.60468 V\n",

-        "di/dt*V_s (for t=0)=100 A/s\n"

-       ]

-      }

-     ],

-     "prompt_number": 12

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.16, Page No 540"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "L=0.006\n",

-      "C=1.2*10**-6\n",

-      "R=100.0\n",

-      "\n",

-      "#Calculations\n",

-      "T=math.pi/math.sqrt(1/(L*C)-(R/(2*L))**2)\n",

-      "T_off=0.2*10**-3\n",

-      "f=1/(2*(T+T_off))    \n",

-      "R=40\n",

-      "T=math.pi/math.sqrt(1/(L*C)-(R/(2*L))**2)\n",

-      "T_off=.2*10**-3\n",

-      "f=1/(2*(T+T_off))    \n",

-      "R=140\n",

-      "T=math.pi/math.sqrt(1/(L*C)-(R/(2*L))**2)\n",

-      "T_off=.2*10**-3\n",

-      "f=1/(2*(T+T_off)) \n",

-      "\n",

-      "#Results\n",

-      "print(\"o/p freq=%.2f Hz\" %f)\n",

-      "print(\"for R=40ohm\")\n",

-      "print(\"upper limit o/p freq=%.1f Hz\" %f)\n",

-      "print(\"for R=140ohm\")\n",

-      "print(\"lower limit o/p freq=%.1f Hz\" %f)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "o/p freq=239.81 Hz\n",

-        "for R=40ohm\n",

-        "upper limit o/p freq=239.8 Hz\n",

-        "for R=140ohm\n",

-        "lower limit o/p freq=239.8 Hz\n"

-       ]

-      }

-     ],

-     "prompt_number": 13

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.17, Page No 540"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "f=5000.0\n",

-      "w=2*math.pi*f\n",

-      "R=3.0\n",

-      "\n",

-      "#Calculations\n",

-      "L=60*10**-6\n",

-      "xie=R/(2*L)\n",

-      "C=7.5*10**-6\n",

-      "w_o=1/math.sqrt(L*C)\n",

-      "w_r=math.sqrt(w_o**2-xie**2)\n",

-      "t_c=math.pi*(1/w-1/w_r)    \n",

-      "fos=1.5\n",

-      "t_q=10*10**-6\n",

-      "f_max=1/(2*math.pi*(t_q*fos/math.pi+1/w_r))    \n",

-      "\n",

-      "#Results\n",

-      "print(\"ckt turn off time=%.2f us\" %(t_c*10**6))\n",

-      "print(\"max possible operating freq=%.1f Hz\" %f_max)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "ckt turn off time=21.39 us\n",

-        "max possible operating freq=5341.4 Hz\n"

-       ]

-      }

-     ],

-     "prompt_number": 14

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.18, Page No 541"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "a=30.0\n",

-      "R=10.0\n",

-      "P=5000.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_s=math.sqrt(P*R*2*math.pi/(2*3)/(math.pi/3+math.sqrt(3)*math.cos(math.radians(2*a))/2))\n",

-      "V_ph=V_s/math.sqrt(3)    \n",

-      "I_or=math.sqrt(P*R)\n",

-      "V_s=I_or*math.pi/(math.sqrt(2)*3*math.cos(math.radians(a)))\n",

-      "V_ph=V_s/math.sqrt(3) \n",

-      "\n",

-      "#Results\n",

-      "print(\"per phase voltage  V_ph=%.3f V\" %V_ph)   \n",

-      "print(\"for constant load current\")\n",

-      "print(\"V_ph=%.2f V\" %V_ph)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "per phase voltage  V_ph=110.384 V\n",

-        "for constant load current\n",

-        "V_ph=110.38 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 15

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.19, Page No 547"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "t=20.0\n",

-      "fos=2.0     #factor of safety\n",

-      "\n",

-      "#Calculations\n",

-      "t_c=t*fos\n",

-      "n=1.0/3\n",

-      "R=20.0\n",

-      "C=n**2*t_c/(4*R*math.log(2)) \n",

-      "\n",

-      "#Results   \n",

-      "print(\"value of capacitor=%.2f uF\" %C)\n",

-      " #printing mistake in the answer in book."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "value of capacitor=0.08 uF\n"

-       ]

-      }

-     ],

-     "prompt_number": 16

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.20, Page No 547"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=220.0\n",

-      "V_p=math.sqrt(2)*V_s/3    \n",

-      "V_L=math.sqrt(3)*V_p    \n",

-      "V_p1=math.sqrt(2)*V_s/math.pi    \n",

-      "V_L1=math.sqrt(3)*V_p1    \n",

-      "V_oh=math.sqrt(V_L**2-V_L1**2)\n",

-      "\n",

-      "#Calculations\n",

-      "THD=V_oh/V_L1    \n",

-      "V_a1=2*V_s/math.pi\n",

-      "V_a5=2*V_s/(5*math.pi)\n",

-      "V_a7=2*V_s/(7*math.pi)\n",

-      "V_a11=2*V_s/(11*math.pi)\n",

-      "R=4.0\n",

-      "L=0.02\n",

-      "f=50\n",

-      "w=2*math.pi*f\n",

-      "Z1=math.sqrt(R**2+(w*L)**2)\n",

-      "Z5=math.sqrt(R**2+(5*w*L)**2)\n",

-      "Z7=math.sqrt(R**2+(7*w*L)**2)\n",

-      "Z11=math.sqrt(R**2+(11*w*L)**2)\n",

-      "I_a1=V_a1/Z1\n",

-      "I_a5=V_a5/Z5\n",

-      "I_a7=V_a7/Z7\n",

-      "I_a11=V_a11/Z11\n",

-      "I_or=math.sqrt((I_a1**2+I_a5**2+I_a7**2+I_a11**2)/2)\n",

-      "P=3*I_or**2*R    \n",

-      "I_s=P/V_s    \n",

-      "I_TA=I_s/3   \n",

-      " \n",

-      "#Results\n",

-      "print(\"rms value of phasor voltages=%.2f V\" %V_p)\n",

-      "print(\"rms value of line voltages=%.2f V\" %V_L)\n",

-      "print(\"fundamental component of phase voltage=%.3f V\" %V_p1)\n",

-      "print(\"fundamental component of line voltages=%.3f V\" %V_L1)\n",

-      "print(\"THD=%.7f\" %THD)\n",

-      "print(\"load power=%.1f W\" %P)\n",

-      "print(\"avg value of source current=%.3f A\" %I_s)\n",

-      "print(\"avg value of thyristor current=%.3f A\" %I_TA)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rms value of phasor voltages=103.71 V\n",

-        "rms value of line voltages=179.63 V\n",

-        "fundamental component of phase voltage=99.035 V\n",

-        "fundamental component of line voltages=171.533 V\n",

-        "THD=0.3108419\n",

-        "load power=2127.6 W\n",

-        "avg value of source current=9.671 A\n",

-        "avg value of thyristor current=3.224 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 17

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Power_Electronics/Chapter8_4.ipynb b/_Power_Electronics/Chapter8_4.ipynb
deleted file mode 100755
index 721a9faf..00000000
--- a/_Power_Electronics/Chapter8_4.ipynb
+++ /dev/null
@@ -1,984 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 08 : Inverters"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.3, Page No 465"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "T=0.1*10**-3\n",

-      "f=1.0/T\n",

-      "k=15*10**-6 #k=th/w\n",

-      "\n",

-      "#Calculations\n",

-      "th=2*math.pi*f*k\n",

-      "X_l=10.0\n",

-      "R=2.0\n",

-      "X_c=R*math.tan(th)+X_l\n",

-      "C=1/(2*math.pi*f*X_c)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"value of C=%.3f uF\" %(C*10**6))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "value of C=1.248 uF\n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.4 Page No 466"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_01=2*V_s/(math.sqrt(2)*math.pi)\n",

-      "R=2.0\n",

-      "I_01=V_01/R\n",

-      "P_d=I_01**2*R    \n",

-      "V=V_s/2\n",

-      "I_s=math.sqrt(2)*I_01/math.pi\n",

-      "P_s=V*I_s\n",

-      "\n",

-      "#Results\n",

-      "print(\"power delivered to load=%.1f W\" %P_d)\n",

-      "print(\"power delivered by both sources=%.1f W\" %(2*P_s))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "power delivered to load=5359.9 W\n",

-        "power delivered by both sources=5359.9 W\n"

-       ]

-      }

-     ],

-     "prompt_number": 2

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.5, Page No 468"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "V_01=4*V_s/(math.pi*math.sqrt(2))\n",

-      "R=1.0\n",

-      "X_L=6.0\n",

-      "X_c=7.0\n",

-      "\n",

-      "#Calculations\n",

-      "I_01=V_01/math.sqrt(R**2+(X_L-X_c)**2)\n",

-      "P=I_01**2*R    \n",

-      "I_s=math.sqrt(2)*I_01*(2*math.cos(math.radians(45)))/math.pi\n",

-      "P_s=V_s*I_s    \n",

-      "\n",

-      "#Results\n",

-      "print(\"power delivered to the source=%.3f kW\" %(P/1000))\n",

-      "print(\"\\npower from the source=%.3f kW\" %(P_s/1000))\n",

-      "   "

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "power delivered to the source=21.440 kW\n",

-        "\n",

-        "power from the source=21.440 kW\n"

-       ]

-      }

-     ],

-     "prompt_number": 3

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.6 Page No 469"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_01=230.0\n",

-      "R=2.0\n",

-      "I_01=V_01/R\n",

-      "I_m=I_01*math.sqrt(2)\n",

-      "I_T1=I_m/2    \n",

-      "I_D1=0    \n",

-      "X_L=8.0\n",

-      "X_C=6.0\n",

-      "\n",

-      "#Calculations\n",

-      "I_01=V_01/math.sqrt(R**2+(X_L-X_C)**2)\n",

-      "phi1=math.degrees(math.atan((X_L-X_C)/R))\n",

-      "I_T1=I_T1*math.sqrt(2)*0.47675    \n",

-      "I_D1=.1507025*I_m/math.sqrt(2)    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"when load R=2 ohm\")\n",

-      "print(\"rms value of thyristor current=%.2f A\" %I_T1)\n",

-      "print(\"rms value of diode current=%.0f A\" %I_D1)\n",

-      "print(\"when load R=2ohm % X_L=8ohm and X_C=6ohm\")\n",

-      "print(\"rms value of thyristor current=%.3f A\" %I_T1)\n",

-      "print(\"rms value of diode current=%.3f A\" %I_D1)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "when load R=2 ohm\n",

-        "rms value of thyristor current=54.83 A\n",

-        "rms value of diode current=17 A\n",

-        "when load R=2ohm % X_L=8ohm and X_C=6ohm\n",

-        "rms value of thyristor current=54.826 A\n",

-        "rms value of diode current=17.331 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 4

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.7 Page No 470"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "R=4.0\n",

-      "f=50.0\n",

-      "w=2*math.pi*f\n",

-      "L=0.035\n",

-      "\n",

-      "#Calculations\n",

-      "C=155*10**-6\n",

-      "X_L=w*L\n",

-      "X_C=1/(w*C)\n",

-      "Z1=math.sqrt(R**2+(X_L-X_C)**2)\n",

-      "phi1=-math.degrees(math.atan((X_L-X_C)/R))\n",

-      "Z3=math.sqrt(R**2+(X_L*3-X_C/3)**2)\n",

-      "phi3=math.degrees(math.atan((X_L*3-X_C/3)/R))\n",

-      "Z5=math.sqrt(R**2+(X_L*5-X_C/5)**2)\n",

-      "phi5=math.degrees(math.atan((X_L*5-X_C/5)/R))\n",

-      "I_m1=4*V_s/(Z1*math.pi)\n",

-      "I_01=I_m1/math.sqrt(2)    \n",

-      "I_m3=4*V_s/(3*Z3*math.pi)\n",

-      "I_m5=4*V_s/(5*Z5*math.pi)\n",

-      "I_m=math.sqrt(I_m1**2+I_m3**2+I_m5**2)\n",

-      "I_0=I_m/math.sqrt(2)\n",

-      "P_0=(I_0)**2*R    \n",

-      "P_01=(I_01)**2*R    \n",

-      "t1=(180-phi1)*math.pi/(180*w)    \n",

-      "t1=(phi1)*math.pi/(180*w)    \n",

-      "\n",

-      "#Results\n",

-      "print(\"rms value of fundamental load current=%.2f A\" %I_01)\n",

-      "print(\"load power=%.1f W\" %P_0)\n",

-      "print(\"fundamental load power=%.1f W\" %P_01)\n",

-      "print(\"rms value of thyristor current=%.3f A\" %(I_m/2))\n",

-      "print(\"conduction time for thyristor=%.3f ms\" %(t1*1000))\n",

-      "print(\"Conduction time for diodes=%.3f ms\" %(t1*1000))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rms value of fundamental load current=20.02 A\n",

-        "load power=1632.5 W\n",

-        "fundamental load power=1602.6 W\n",

-        "rms value of thyristor current=14.285 A\n",

-        "conduction time for thyristor=3.736 ms\n",

-        "Conduction time for diodes=3.736 ms\n"

-       ]

-      }

-     ],

-     "prompt_number": 5

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.8, Page No 473"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "V_01=2*V_s/(math.sqrt(2)*math.pi)    \n",

-      "R=10.0\n",

-      "\n",

-      "#Calculations\n",

-      "I_01=V_01/R\n",

-      "P=I_01**2*R    \n",

-      "V_or=math.sqrt((V_s/2)**2)\n",

-      "P=V_or**2/R    \n",

-      "I_TP=V_s/(2*R)\n",

-      "I_or=I_TP\n",

-      "pf=I_01**2*R/(V_or*I_or)  \n",

-      "DF=V_01/V_or  \n",

-      "V_oh=math.sqrt(V_or**2-V_01**2)\n",

-      "THD=V_oh/V_01 \n",

-      "V_03=V_01/3\n",

-      "HF=V_03/V_01\n",

-      "\n",

-      "#Results\n",

-      "print(\"fundamental rms o/p voltage=%.3f V\" %V_01)\n",

-      "print(\"fundamental power to load=%.1f W\" %P)\n",

-      "print(\"total o/p power to load=%.1f W\" %P)\n",

-      "print(\"avg SCR current=%.2f A\" %(I_TP*180/360))\n",

-      "print(\"i/p pf=%.3f\" %pf)  \n",

-      "print(\"distortion factor=%.1f\" %DF)\n",

-      "print(\"THD=%.3f\" %THD)    \n",

-      "print(\"harmonic factor=%.4f\" %HF)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "fundamental rms o/p voltage=103.536 V\n",

-        "fundamental power to load=1322.5 W\n",

-        "total o/p power to load=1322.5 W\n",

-        "avg SCR current=5.75 A\n",

-        "i/p pf=0.811\n",

-        "distortion factor=0.9\n",

-        "THD=0.483\n",

-        "harmonic factor=0.3333\n"

-       ]

-      }

-     ],

-     "prompt_number": 6

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.9 Page No 474"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=60\n",

-      "R=3.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_or=math.sqrt(V_s**2*math.pi/math.pi)    \n",

-      "V_01=4*V_s/(math.sqrt(2)*math.pi)    \n",

-      "P_o=V_or**2/R    \n",

-      "P_01=V_01**2/R    \n",

-      "I_s=V_s/R    \n",

-      "I_avg=I_s*math.pi/(2*math.pi)    \n",

-      "V_03=V_01/3\n",

-      "HF=V_03/V_01    \n",

-      "V_oh=math.sqrt(V_or**2-V_01**2)\n",

-      "THD=V_oh/V_01   \n",

-      "\n",

-      "#Results\n",

-      "print(\"rms value of o/p voltage=%.0f V\" %V_or)\n",

-      "print(\"o/p power=%.0f W\" %P_o)\n",

-      "print(\"fundamental component of rms voltage=%.2f V\" %V_01)\n",

-      "print(\"fundamental freq o/p power=%.2f W\" %P_01) \n",

-      "print(\"peak current=%.0f A\" %I_s)\n",

-      "print(\"avg current of each transistor=%.0f A\" %I_avg)\n",

-      "print(\"peak reverse blocking voltage=%.0f V\" %V_s)\n",

-      "print(\"harmonic factor=%.4f\" %HF)\n",

-      "print(\"THD=%.4f\" %THD)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rms value of o/p voltage=60 V\n",

-        "o/p power=1200 W\n",

-        "fundamental component of rms voltage=54.02 V\n",

-        "fundamental freq o/p power=972.68 W\n",

-        "peak current=20 A\n",

-        "avg current of each transistor=10 A\n",

-        "peak reverse blocking voltage=60 V\n",

-        "harmonic factor=0.3333\n",

-        "THD=0.4834\n"

-       ]

-      }

-     ],

-     "prompt_number": 7

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.10 Page No 475"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=220.0\n",

-      "R=6.0\n",

-      "f=50.0\n",

-      "w=2*math.pi*f\n",

-      "L=0.03\n",

-      "C=180*10**-6\n",

-      "X_L=w*L\n",

-      "X_C=1/(w*C)\n",

-      "\n",

-      "#Calculations\n",

-      "V_or=math.sqrt(V_s**2*math.pi/math.pi)\n",

-      "V_01=4*V_s/(math.sqrt(2)*math.pi)\n",

-      "V_oh=math.sqrt(V_or**2-V_01**2)\n",

-      "THD=V_oh/V_01    \n",

-      "print(\"THD of voltage=%.4f\" %THD)\n",

-      "DF=V_01/V_or    \n",

-      "Z1=math.sqrt(R**2+(X_L-X_C)**2)\n",

-      "phi1=-math.degrees(math.atan((X_L-X_C)/R))\n",

-      "Z3=math.sqrt(R**2+(X_L*3-X_C/3)**2)\n",

-      "phi3=math.degrees(math.atan((X_L*3-X_C/3)/R))\n",

-      "Z5=math.sqrt(R**2+(X_L*5-X_C/5)**2)\n",

-      "phi5=math.degrees(math.atan((X_L*5-X_C/5)/R))\n",

-      "Z7=math.sqrt(R**2+(X_L*7-X_C/7)**2)\n",

-      "phi7=math.degrees(math.atan((X_L*7-X_C/7)/R))\n",

-      "I_01=19.403\n",

-      "I_m1=4*V_s/(Z1*math.pi)\n",

-      "I_m3=4*V_s/(3*Z3*math.pi)\n",

-      "I_m5=4*V_s/(5*Z5*math.pi)\n",

-      "I_m7=4*V_s/(7*Z7*math.pi)\n",

-      "I_m=math.sqrt(I_m1**2+I_m3**2+I_m5**2+I_m7**2)\n",

-      "I_or=I_m/math.sqrt(2)\n",

-      "I_oh=math.sqrt((I_m**2-I_m1**2)/2)\n",

-      "THD=I_oh/I_01    \n",

-      "DF=I_01/I_or    \n",

-      "P_o=I_or**2*R    \n",

-      "I_avg=P_o/V_s    \n",

-      "t1=(180-phi1)*math.pi/(180*w)    \n",

-      "t1=1/(2*f)-t1    \n",

-      "I_p=I_m1    \n",

-      "I_t1=.46135*I_p \n",

-      "\n",

-      "#Results\n",

-      "print(\"\\nDF=%.1f\" %DF)\n",

-      "print(\"THD of current=%.4f\" %THD)   \n",

-      "print(\"DF=%.3f\" %DF)\n",

-      "print(\"load power=%.1f W\" %P_o)\n",

-      "print(\"avg value of load current=%.2f A\" %I_avg)\n",

-      "print(\"conduction time for thyristor=%.0f ms\" %(t1*1000))\n",

-      "print(\"conduction time for diodes=%.0f ms\" %(t1*1000))\n",

-      "print(\"peak transistor current=%.2f A\" %I_p)\n",

-      "print(\"rms transistor current=%.2f A\" %I_t1)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "THD of voltage=0.4834\n",

-        "\n",

-        "DF=1.0\n",

-        "THD of current=0.1557\n",

-        "DF=0.988\n",

-        "load power=2313.5 W\n",

-        "avg value of load current=10.52 A\n",

-        "conduction time for thyristor=3 ms\n",

-        "conduction time for diodes=3 ms\n",

-        "peak transistor current=27.44 A\n",

-        "rms transistor current=12.66 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 8

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.11 Page No 497"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=450.0\n",

-      "R=10.0\n",

-      "\n",

-      "#Calculations\n",

-      "I_or=math.sqrt((V_s/(3*R))**2*2/3+(2*V_s/(3*R))**2*1/3)    \n",

-      "I_T1=math.sqrt((1/(2*math.pi))*((V_s/(3*R))**2*2*math.pi/3+(2*V_s/(3*R))**2*math.pi/3))   \n",

-      "P=3*I_or**2*R    \n",

-      "I_or=math.sqrt((1/(math.pi))*((V_s/(2*R))**2*2*math.pi/3))    \n",

-      "I_T1=math.sqrt((1/(2*math.pi))*((V_s/(2*R))**2*2*math.pi/3))    \n",

-      "P=3*I_or**2*R    \n",

-      "\n",

-      "#Results\n",

-      "print(\"for 180deg mode\")\n",

-      "print(\"rms value of load current=%.3f A\" %I_or)\n",

-      "print(\"power delivered to load=%.1f kW\" %(P/1000))\n",

-      "print(\"rms value of load current=%.0f A\" %I_T1)\n",

-      "print(\"for 120deg mode\")\n",

-      "print(\"rms value of load current=%.3f A\" %I_or)\n",

-      "print(\"rms value of load current=%.2f A\" %I_T1)\n",

-      "print(\"power delivered to load=%.3f kW\" %(P/1000))\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for 180deg mode\n",

-        "rms value of load current=18.371 A\n",

-        "power delivered to load=10.1 kW\n",

-        "rms value of load current=13 A\n",

-        "for 120deg mode\n",

-        "rms value of load current=18.371 A\n",

-        "rms value of load current=12.99 A\n",

-        "power delivered to load=10.125 kW\n"

-       ]

-      }

-     ],

-     "prompt_number": 9

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.12, Page No 510"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "R=10.0\n",

-      "f=50.0\n",

-      "w=2*math.pi*f\n",

-      "L=0.03\n",

-      "\n",

-      "#Calculations\n",

-      "X_L=w*L\n",

-      "V_or=math.sqrt(V_s**2*math.pi/math.pi)\n",

-      "V_01=4*V_s/(math.sqrt(2)*math.pi)\n",

-      "Z1=math.sqrt(R**2+(X_L)**2)\n",

-      "phi1=-math.degrees(math.atan((X_L)/R))\n",

-      "Z3=math.sqrt(R**2+(X_L*3)**2)\n",

-      "phi3=math.degrees(math.atan((X_L*3)/R))\n",

-      "Z5=math.sqrt(R**2+(X_L*5)**2)\n",

-      "phi5=math.degrees(math.atan((X_L*5)/R))\n",

-      "Z7=math.sqrt(R**2+(X_L*7)**2)\n",

-      "phi7=math.degrees(math.atan((X_L*7)/R))\n",

-      "I_m1=4*V_s/(math.sqrt(2)*Z1*math.pi)\n",

-      "I_m3=4*V_s/(math.sqrt(2)*3*Z3*math.pi)\n",

-      "I_m5=4*V_s/(math.sqrt(2)*5*Z5*math.pi)\n",

-      "I_m7=4*V_s/(math.sqrt(2)*7*Z7*math.pi)\n",

-      "I_m=math.sqrt(I_m1**2+I_m3**2+I_m5**2+I_m7**2)\n",

-      "P=I_m**2*R    \n",

-      "I_01=I_m1*math.sin(math.radians(45))\n",

-      "I_03=I_m3*math.sin(math.radians(3*45))\n",

-      "I_05=I_m5*math.sin(math.radians(5*45))\n",

-      "I_07=I_m7*math.sin(math.radians(7*45))\n",

-      "I_0=(I_01**2+I_03**2+I_05**2+I_07**2)\n",

-      "P=I_0*R    \n",

-      "g=(180-90)/3+45/2\n",

-      "I_01=2*I_m1*math.sin(math.radians(g))*math.sin(math.radians(45/2))\n",

-      "I_03=2*I_m3*math.sin(math.radians(g*3))*math.sin(math.radians(3*45/2))\n",

-      "I_05=2*I_m5*math.sin(math.radians(g*5))*math.sin(math.radians(5*45/2))\n",

-      "I_07=2*I_m7*math.sin(math.radians(g*7))*math.sin(math.radians(7*45/2))\n",

-      "I_0=(I_01**2+I_03**2+I_05**2+I_07**2)\n",

-      "P=I_0*R    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"using square wave o/p\")\n",

-      "print(\"power delivered=%.2f W\" %P)\n",

-      "print(\"using quasi-square wave o/p\")\n",

-      "print(\"power delivered=%.2f W\" %P)\n",

-      "print(\"using two symmitrical spaced pulses\")\n",

-      "print(\"power delivered=%.2f W\" %P)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "using square wave o/p\n",

-        "power delivered=845.87 W\n",

-        "using quasi-square wave o/p\n",

-        "power delivered=845.87 W\n",

-        "using two symmitrical spaced pulses\n",

-        "power delivered=845.87 W\n"

-       ]

-      }

-     ],

-     "prompt_number": 10

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.14, Page No 520"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "f=50.0\n",

-      "T=1/f\n",

-      "I=0.5\n",

-      "\n",

-      "#Calculations\n",

-      "di=I/T     #di=di/dt\n",

-      "V_s=220.0\n",

-      "L=V_s/di    \n",

-      "t=20*10**-6\n",

-      "fos=2     #factor of safety\n",

-      "t_c=t*fos\n",

-      "R=10\n",

-      "C=t_c/(R*math.log(2))\n",

-      "\n",

-      "#Results    \n",

-      "print(\"source inductance=%.1f H\" %L)\n",

-      "print(\"commutating capacitor=%.2f uF\" %(C*10**6))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "source inductance=8.8 H\n",

-        "commutating capacitor=5.77 uF\n"

-       ]

-      }

-     ],

-     "prompt_number": 11

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.15, Page No 539"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "R=10.0\n",

-      "L=.01\n",

-      "C=10*10**-6\n",

-      "#Calculations\n",

-      "if (R**2)<(4*L/C) :\n",

-      "    print(\"ckt will commutate on its own\")\n",

-      "else:\n",

-      "    print(\"ckt will not commutate on its own\")\n",

-      "\n",

-      "xie=R/(2*L)\n",

-      "w_o=1/math.sqrt(L*C)\n",

-      "w_r=math.sqrt(w_o**2-xie**2)\n",

-      "phi=math.degrees(math.atan(xie/w_r))\n",

-      "t=math.pi/w_r\n",

-      "V_s=1\n",

-      "v_L=V_s*(w_o/w_r)*math.exp(-xie*t)*math.cos(math.radians(180+phi))\n",

-      "v_c=V_s*(1-(w_o/w_r)*math.exp(-xie*t)*math.cos(math.radians(180-phi)))   \n",

-      "di=V_s/L    \n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"voltage across inductor(*V_s)=%.5f V\" %v_L) \n",

-      "print(\"voltage across capacitor(*V_s)=%.5f V\" %v_c)\n",

-      "print(\"di/dt*V_s (for t=0)=%.0f A/s\" %di)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "ckt will commutate on its own\n",

-        "voltage across inductor(*V_s)=-0.60468 V\n",

-        "voltage across capacitor(*V_s)=1.60468 V\n",

-        "di/dt*V_s (for t=0)=100 A/s\n"

-       ]

-      }

-     ],

-     "prompt_number": 12

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.16, Page No 540"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "L=0.006\n",

-      "C=1.2*10**-6\n",

-      "R=100.0\n",

-      "\n",

-      "#Calculations\n",

-      "T=math.pi/math.sqrt(1/(L*C)-(R/(2*L))**2)\n",

-      "T_off=0.2*10**-3\n",

-      "f=1/(2*(T+T_off))    \n",

-      "R=40\n",

-      "T=math.pi/math.sqrt(1/(L*C)-(R/(2*L))**2)\n",

-      "T_off=.2*10**-3\n",

-      "f=1/(2*(T+T_off))    \n",

-      "R=140\n",

-      "T=math.pi/math.sqrt(1/(L*C)-(R/(2*L))**2)\n",

-      "T_off=.2*10**-3\n",

-      "f=1/(2*(T+T_off)) \n",

-      "\n",

-      "#Results\n",

-      "print(\"o/p freq=%.2f Hz\" %f)\n",

-      "print(\"for R=40ohm\")\n",

-      "print(\"upper limit o/p freq=%.1f Hz\" %f)\n",

-      "print(\"for R=140ohm\")\n",

-      "print(\"lower limit o/p freq=%.1f Hz\" %f)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "o/p freq=239.81 Hz\n",

-        "for R=40ohm\n",

-        "upper limit o/p freq=239.8 Hz\n",

-        "for R=140ohm\n",

-        "lower limit o/p freq=239.8 Hz\n"

-       ]

-      }

-     ],

-     "prompt_number": 13

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.17, Page No 540"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "f=5000.0\n",

-      "w=2*math.pi*f\n",

-      "R=3.0\n",

-      "\n",

-      "#Calculations\n",

-      "L=60*10**-6\n",

-      "xie=R/(2*L)\n",

-      "C=7.5*10**-6\n",

-      "w_o=1/math.sqrt(L*C)\n",

-      "w_r=math.sqrt(w_o**2-xie**2)\n",

-      "t_c=math.pi*(1/w-1/w_r)    \n",

-      "fos=1.5\n",

-      "t_q=10*10**-6\n",

-      "f_max=1/(2*math.pi*(t_q*fos/math.pi+1/w_r))    \n",

-      "\n",

-      "#Results\n",

-      "print(\"ckt turn off time=%.2f us\" %(t_c*10**6))\n",

-      "print(\"max possible operating freq=%.1f Hz\" %f_max)\n",

-      " #Answers have small variations from that in the book due to difference in the rounding off of digits."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "ckt turn off time=21.39 us\n",

-        "max possible operating freq=5341.4 Hz\n"

-       ]

-      }

-     ],

-     "prompt_number": 14

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.18, Page No 541"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "a=30.0\n",

-      "R=10.0\n",

-      "P=5000.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_s=math.sqrt(P*R*2*math.pi/(2*3)/(math.pi/3+math.sqrt(3)*math.cos(math.radians(2*a))/2))\n",

-      "V_ph=V_s/math.sqrt(3)    \n",

-      "I_or=math.sqrt(P*R)\n",

-      "V_s=I_or*math.pi/(math.sqrt(2)*3*math.cos(math.radians(a)))\n",

-      "V_ph=V_s/math.sqrt(3) \n",

-      "\n",

-      "#Results\n",

-      "print(\"per phase voltage  V_ph=%.3f V\" %V_ph)   \n",

-      "print(\"for constant load current\")\n",

-      "print(\"V_ph=%.2f V\" %V_ph)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "per phase voltage  V_ph=110.384 V\n",

-        "for constant load current\n",

-        "V_ph=110.38 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 15

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.19, Page No 547"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "t=20.0\n",

-      "fos=2.0     #factor of safety\n",

-      "\n",

-      "#Calculations\n",

-      "t_c=t*fos\n",

-      "n=1.0/3\n",

-      "R=20.0\n",

-      "C=n**2*t_c/(4*R*math.log(2)) \n",

-      "\n",

-      "#Results   \n",

-      "print(\"value of capacitor=%.2f uF\" %C)\n",

-      " #printing mistake in the answer in book."

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "value of capacitor=0.08 uF\n"

-       ]

-      }

-     ],

-     "prompt_number": 16

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 8.20, Page No 547"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=220.0\n",

-      "V_p=math.sqrt(2)*V_s/3    \n",

-      "V_L=math.sqrt(3)*V_p    \n",

-      "V_p1=math.sqrt(2)*V_s/math.pi    \n",

-      "V_L1=math.sqrt(3)*V_p1    \n",

-      "V_oh=math.sqrt(V_L**2-V_L1**2)\n",

-      "\n",

-      "#Calculations\n",

-      "THD=V_oh/V_L1    \n",

-      "V_a1=2*V_s/math.pi\n",

-      "V_a5=2*V_s/(5*math.pi)\n",

-      "V_a7=2*V_s/(7*math.pi)\n",

-      "V_a11=2*V_s/(11*math.pi)\n",

-      "R=4.0\n",

-      "L=0.02\n",

-      "f=50\n",

-      "w=2*math.pi*f\n",

-      "Z1=math.sqrt(R**2+(w*L)**2)\n",

-      "Z5=math.sqrt(R**2+(5*w*L)**2)\n",

-      "Z7=math.sqrt(R**2+(7*w*L)**2)\n",

-      "Z11=math.sqrt(R**2+(11*w*L)**2)\n",

-      "I_a1=V_a1/Z1\n",

-      "I_a5=V_a5/Z5\n",

-      "I_a7=V_a7/Z7\n",

-      "I_a11=V_a11/Z11\n",

-      "I_or=math.sqrt((I_a1**2+I_a5**2+I_a7**2+I_a11**2)/2)\n",

-      "P=3*I_or**2*R    \n",

-      "I_s=P/V_s    \n",

-      "I_TA=I_s/3   \n",

-      " \n",

-      "#Results\n",

-      "print(\"rms value of phasor voltages=%.2f V\" %V_p)\n",

-      "print(\"rms value of line voltages=%.2f V\" %V_L)\n",

-      "print(\"fundamental component of phase voltage=%.3f V\" %V_p1)\n",

-      "print(\"fundamental component of line voltages=%.3f V\" %V_L1)\n",

-      "print(\"THD=%.7f\" %THD)\n",

-      "print(\"load power=%.1f W\" %P)\n",

-      "print(\"avg value of source current=%.3f A\" %I_s)\n",

-      "print(\"avg value of thyristor current=%.3f A\" %I_TA)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rms value of phasor voltages=103.71 V\n",

-        "rms value of line voltages=179.63 V\n",

-        "fundamental component of phase voltage=99.035 V\n",

-        "fundamental component of line voltages=171.533 V\n",

-        "THD=0.3108419\n",

-        "load power=2127.6 W\n",

-        "avg value of source current=9.671 A\n",

-        "avg value of thyristor current=3.224 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 17

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Power_Electronics/Chapter9.ipynb b/_Power_Electronics/Chapter9.ipynb
deleted file mode 100755
index 052c4736..00000000
--- a/_Power_Electronics/Chapter9.ipynb
+++ /dev/null
@@ -1,388 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 09 : AC Voltage Controllers"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 9.1, Page No 560"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "a=45.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_or=(V_m/2)*math.sqrt(1/math.pi*((2*math.pi-a*math.pi/180)+math.sin(math.radians(2*a))/2))    \n",

-      "R=20\n",

-      "I_or=V_or/R\n",

-      "P_o=I_or**2*R    \n",

-      "I_s=I_or\n",

-      "VA=V_s*I_s\n",

-      "pf=P_o/VA    \n",

-      "V_o=math.sqrt(2)*V_s/(2*math.pi)*(math.cos(math.radians(a))-1)\n",

-      "I_ON=V_o/R  \n",

-      "\n",

-      "#Results\n",

-      "print(\"rms value of o/p voltage=%.3f V\" %V_or)\n",

-      "print(\"load power=%.1f W\" %P_o)\n",

-      "print(\"i/p pf=%.4f\" %pf)\n",

-      "print(\"avg i/p current=%.4f A\" %I_ON)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rms value of o/p voltage=224.716 V\n",

-        "load power=2524.9 W\n",

-        "i/p pf=0.9770\n",

-        "avg i/p current=-0.7581 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 9.2, Page No 560"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "a=45.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_or=(V_s)*math.sqrt(1/math.pi*((math.pi-a*math.pi/180)+math.sin(math.radians(2*a))/2))    \n",

-      "R=20\n",

-      "I_or=V_or/R\n",

-      "P_o=I_or**2*R    \n",

-      "I_s=I_or\n",

-      "VA=V_s*I_s\n",

-      "pf=P_o/VA    \n",

-      "I_TA=math.sqrt(2)*V_s/(2*math.pi*R)*(math.cos(math.radians(a))+1)   \n",

-      "I_Tr=math.sqrt(2)*V_s/(2*R)*math.sqrt(1/math.pi*((math.pi-a*math.pi/180)+math.sin(math.radians(2*a))/2)) \n",

-      "\n",

-      "#Results\n",

-      "print(\"rms value of o/p voltage=%.3f V\" %V_or)\n",

-      "print(\"load power=%.2f W\" %P_o)\n",

-      "print(\"i/p pf=%.2f\" %pf)\n",

-      "print(\"avg thyristor current=%.2f A\" %I_TA)   \n",

-      "print(\"rms value of thyristor current=%.2f A\" %I_Tr)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rms value of o/p voltage=219.304 V\n",

-        "load power=2404.71 W\n",

-        "i/p pf=0.95\n",

-        "avg thyristor current=4.42 A\n",

-        "rms value of thyristor current=7.75 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 2

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 9.3 Page No 564"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "n=6.0 #on cycles\n",

-      "m=4.0 #off cycles\n",

-      "\n",

-      "#Calculations\n",

-      "k=n/(n+m)\n",

-      "V_or=V_s*math.sqrt(k)    \n",

-      "pf=math.sqrt(k)    \n",

-      "R=15\n",

-      "I_m=V_s*math.sqrt(2)/R\n",

-      "I_TA=k*I_m/math.pi\n",

-      "I_TR=I_m*math.sqrt(k)/2  \n",

-      "   \n",

-      "#Results\n",

-      "print(\"rms value of o/ voltage=%.2f V\" %V_or)\n",

-      "print(\"i/p pf=%.2f\" %pf)\n",

-      "print(\"avg thyristor current=%.2f A\" %I_TA)  \n",

-      "print(\"rms value of thyristor current=%.2f A\" %I_TR)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rms value of o/ voltage=178.16 V\n",

-        "i/p pf=0.77\n",

-        "avg thyristor current=4.14 A\n",

-        "rms value of thyristor current=8.40 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 3

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 9.4, Page No 569"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "R=3.0\n",

-      "\n",

-      "#Calculations\n",

-      "I_TAM1=2*V_m/(2*math.pi*R)  \n",

-      "I_TRM2=V_m/(2*R)    \n",

-      "f=50\n",

-      "w=2*math.pi*f\n",

-      "t_c=math.pi/w    \n",

-      " \n",

-      "#Results\n",

-      "print(\"max value of avg thyristor current=%.3f A\" %I_TAM1)\n",

-      "print(\"max value of avg thyristor current=%.3f A\" %I_TRM2)\n",

-      "print(\"ckt turn off time=%.0f ms\" %(t_c*1000))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "max value of avg thyristor current=34.512 A\n",

-        "max value of avg thyristor current=54.212 A\n",

-        "ckt turn off time=10 ms\n"

-       ]

-      }

-     ],

-     "prompt_number": 4

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 9.5 Page No 575"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "R=3.0\n",

-      "X_L=4.0\n",

-      "\n",

-      "#Calculations\n",

-      "phi=math.degrees(math.atan(X_L/R))    \n",

-      "V_s=230\n",

-      "Z=math.sqrt(R**2+X_L**2)\n",

-      "I_or=V_s/Z    \n",

-      "P=I_or**2*R    \n",

-      "I_s=I_or\n",

-      "pf=P/(V_s*I_s)    \n",

-      "I_TAM=math.sqrt(2)*V_s/(math.pi*Z)    \n",

-      "I_Tm=math.sqrt(2)*V_s/(2*Z)    \n",

-      "f=50\n",

-      "w=2*math.pi*f\n",

-      "di=math.sqrt(2)*V_s*w/Z    \n",

-      "\n",

-      "#Results\n",

-      "print(\"min firing angle=%.2f deg\" %phi)\n",

-      "print(\"\\nmax firing angle=%.0f deg\" %180)\n",

-      "print(\"i/p pf=%.1f\" %pf)\n",

-      "print(\"max value of rms load current=%.0f A\" %I_or)\n",

-      "print(\"max power=%.0f W\" %P)\n",

-      "print(\"max value of avg thyristor current=%.3f A\" %I_TAM)\n",

-      "print(\"max value of rms thyristor current=%.3f A\" %I_Tm)\n",

-      "print(\"di/dt=%.0f A/s\" %di)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "min firing angle=53.13 deg\n",

-        "\n",

-        "max firing angle=180 deg\n",

-        "i/p pf=0.6\n",

-        "max value of rms load current=46 A\n",

-        "max power=6348 W\n",

-        "max value of avg thyristor current=20.707 A\n",

-        "max value of rms thyristor current=32.527 A\n",

-        "di/dt=20437 A/s\n"

-       ]

-      }

-     ],

-     "prompt_number": 5

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 9.6 Page No 576"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=230.0\n",

-      "R=3.0 #ohm\n",

-      "X_L=5.0 #ohm\n",

-      "a=120.0 #firing angle delay\n",

-      "\n",

-      "#Calculations\n",

-      "phi=math.degrees(math.atan(X_L/R))\n",

-      "b=0\n",

-      "i=1\n",

-      "while (i>0) :\n",

-      "    LHS=math.sin(math.radians(b-a))\n",

-      "    RHS=math.sin(math.radians(a-phi))*math.exp(-(R/X_L)*(b-a)*math.pi/180)\n",

-      "    if math.fabs(LHS-RHS)<= 0.01 :\n",

-      "        B=b\n",

-      "        i=2\n",

-      "        break\n",

-      "   \n",

-      "    b=b+.1   \n",

-      "V_or=math.sqrt(2)*V*math.sqrt((1/(2*math.pi))*((B-a)*math.pi/180+(math.sin(math.radians(2*a))-math.sin(math.radians(2*B)))/2))\n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"Extinction angle=%.1f deg\" %B) #answer in the book is wrong as formulae for RHS is wrongly employed\n",

-      "print(\"rms value of output voltage=%.2f V\" %V_or) #answer do not match due to wrong B in book\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Extinction angle=156.1 deg\n",

-        "rms value of output voltage=97.75 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 6

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 9.8, Page No 581"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "a=60.0\n",

-      "R=20.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_or=math.sqrt((V_m**2/(2*math.pi))*(a*math.pi/180-math.sin(math.radians(2*a))/2)+(2*V_m**2/(math.pi))*(math.pi-a*math.pi/180+math.sin(math.radians(2*a))/2))    \n",

-      "I_T1r=(V_m/R)*math.sqrt(1/math.pi*((math.pi-a*math.pi/180)+math.sin(math.radians(2*a))/2))    \n",

-      "I_T3r=(V_m/(2*R))*math.sqrt(1/math.pi*((a*math.pi/180)-math.sin(math.radians(2*a))/2))    \n",

-      "I1=math.sqrt(2)*I_T1r\n",

-      "I3=math.sqrt((math.sqrt(2)*I_T1r)**2+(math.sqrt(2)*I_T3r)**2)\n",

-      "r=V_s*(I1+I3)    \n",

-      "P_o=V_or**2/R\n",

-      "pf=P_o/r    \n",

-      "\n",

-      "#Results\n",

-      "print(\"rms value of o/p voltage=%.2f V\" %V_or)\n",

-      "print(\"rms value of current for upper thyristors=%.2f A\" %I_T1r)\n",

-      "print(\"rms value of current for lower thyristors=%.2f A\" %I_T3r)\n",

-      "print(\"t/f VA rating=%.2f VA\" %r)\n",

-      "print(\"i/p pf=%.2f\" %pf)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rms value of o/p voltage=424.94 V\n",

-        "rms value of current for upper thyristors=14.59 A\n",

-        "rms value of current for lower thyristors=3.60 A\n",

-        "t/f VA rating=9631.61 VA\n",

-        "i/p pf=0.94\n"

-       ]

-      }

-     ],

-     "prompt_number": 7

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Power_Electronics/Chapter9_1.ipynb b/_Power_Electronics/Chapter9_1.ipynb
deleted file mode 100755
index 052c4736..00000000
--- a/_Power_Electronics/Chapter9_1.ipynb
+++ /dev/null
@@ -1,388 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 09 : AC Voltage Controllers"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 9.1, Page No 560"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "a=45.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_or=(V_m/2)*math.sqrt(1/math.pi*((2*math.pi-a*math.pi/180)+math.sin(math.radians(2*a))/2))    \n",

-      "R=20\n",

-      "I_or=V_or/R\n",

-      "P_o=I_or**2*R    \n",

-      "I_s=I_or\n",

-      "VA=V_s*I_s\n",

-      "pf=P_o/VA    \n",

-      "V_o=math.sqrt(2)*V_s/(2*math.pi)*(math.cos(math.radians(a))-1)\n",

-      "I_ON=V_o/R  \n",

-      "\n",

-      "#Results\n",

-      "print(\"rms value of o/p voltage=%.3f V\" %V_or)\n",

-      "print(\"load power=%.1f W\" %P_o)\n",

-      "print(\"i/p pf=%.4f\" %pf)\n",

-      "print(\"avg i/p current=%.4f A\" %I_ON)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rms value of o/p voltage=224.716 V\n",

-        "load power=2524.9 W\n",

-        "i/p pf=0.9770\n",

-        "avg i/p current=-0.7581 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 9.2, Page No 560"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "a=45.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_or=(V_s)*math.sqrt(1/math.pi*((math.pi-a*math.pi/180)+math.sin(math.radians(2*a))/2))    \n",

-      "R=20\n",

-      "I_or=V_or/R\n",

-      "P_o=I_or**2*R    \n",

-      "I_s=I_or\n",

-      "VA=V_s*I_s\n",

-      "pf=P_o/VA    \n",

-      "I_TA=math.sqrt(2)*V_s/(2*math.pi*R)*(math.cos(math.radians(a))+1)   \n",

-      "I_Tr=math.sqrt(2)*V_s/(2*R)*math.sqrt(1/math.pi*((math.pi-a*math.pi/180)+math.sin(math.radians(2*a))/2)) \n",

-      "\n",

-      "#Results\n",

-      "print(\"rms value of o/p voltage=%.3f V\" %V_or)\n",

-      "print(\"load power=%.2f W\" %P_o)\n",

-      "print(\"i/p pf=%.2f\" %pf)\n",

-      "print(\"avg thyristor current=%.2f A\" %I_TA)   \n",

-      "print(\"rms value of thyristor current=%.2f A\" %I_Tr)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rms value of o/p voltage=219.304 V\n",

-        "load power=2404.71 W\n",

-        "i/p pf=0.95\n",

-        "avg thyristor current=4.42 A\n",

-        "rms value of thyristor current=7.75 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 2

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 9.3 Page No 564"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "n=6.0 #on cycles\n",

-      "m=4.0 #off cycles\n",

-      "\n",

-      "#Calculations\n",

-      "k=n/(n+m)\n",

-      "V_or=V_s*math.sqrt(k)    \n",

-      "pf=math.sqrt(k)    \n",

-      "R=15\n",

-      "I_m=V_s*math.sqrt(2)/R\n",

-      "I_TA=k*I_m/math.pi\n",

-      "I_TR=I_m*math.sqrt(k)/2  \n",

-      "   \n",

-      "#Results\n",

-      "print(\"rms value of o/ voltage=%.2f V\" %V_or)\n",

-      "print(\"i/p pf=%.2f\" %pf)\n",

-      "print(\"avg thyristor current=%.2f A\" %I_TA)  \n",

-      "print(\"rms value of thyristor current=%.2f A\" %I_TR)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rms value of o/ voltage=178.16 V\n",

-        "i/p pf=0.77\n",

-        "avg thyristor current=4.14 A\n",

-        "rms value of thyristor current=8.40 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 3

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 9.4, Page No 569"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "R=3.0\n",

-      "\n",

-      "#Calculations\n",

-      "I_TAM1=2*V_m/(2*math.pi*R)  \n",

-      "I_TRM2=V_m/(2*R)    \n",

-      "f=50\n",

-      "w=2*math.pi*f\n",

-      "t_c=math.pi/w    \n",

-      " \n",

-      "#Results\n",

-      "print(\"max value of avg thyristor current=%.3f A\" %I_TAM1)\n",

-      "print(\"max value of avg thyristor current=%.3f A\" %I_TRM2)\n",

-      "print(\"ckt turn off time=%.0f ms\" %(t_c*1000))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "max value of avg thyristor current=34.512 A\n",

-        "max value of avg thyristor current=54.212 A\n",

-        "ckt turn off time=10 ms\n"

-       ]

-      }

-     ],

-     "prompt_number": 4

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 9.5 Page No 575"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "R=3.0\n",

-      "X_L=4.0\n",

-      "\n",

-      "#Calculations\n",

-      "phi=math.degrees(math.atan(X_L/R))    \n",

-      "V_s=230\n",

-      "Z=math.sqrt(R**2+X_L**2)\n",

-      "I_or=V_s/Z    \n",

-      "P=I_or**2*R    \n",

-      "I_s=I_or\n",

-      "pf=P/(V_s*I_s)    \n",

-      "I_TAM=math.sqrt(2)*V_s/(math.pi*Z)    \n",

-      "I_Tm=math.sqrt(2)*V_s/(2*Z)    \n",

-      "f=50\n",

-      "w=2*math.pi*f\n",

-      "di=math.sqrt(2)*V_s*w/Z    \n",

-      "\n",

-      "#Results\n",

-      "print(\"min firing angle=%.2f deg\" %phi)\n",

-      "print(\"\\nmax firing angle=%.0f deg\" %180)\n",

-      "print(\"i/p pf=%.1f\" %pf)\n",

-      "print(\"max value of rms load current=%.0f A\" %I_or)\n",

-      "print(\"max power=%.0f W\" %P)\n",

-      "print(\"max value of avg thyristor current=%.3f A\" %I_TAM)\n",

-      "print(\"max value of rms thyristor current=%.3f A\" %I_Tm)\n",

-      "print(\"di/dt=%.0f A/s\" %di)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "min firing angle=53.13 deg\n",

-        "\n",

-        "max firing angle=180 deg\n",

-        "i/p pf=0.6\n",

-        "max value of rms load current=46 A\n",

-        "max power=6348 W\n",

-        "max value of avg thyristor current=20.707 A\n",

-        "max value of rms thyristor current=32.527 A\n",

-        "di/dt=20437 A/s\n"

-       ]

-      }

-     ],

-     "prompt_number": 5

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 9.6 Page No 576"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=230.0\n",

-      "R=3.0 #ohm\n",

-      "X_L=5.0 #ohm\n",

-      "a=120.0 #firing angle delay\n",

-      "\n",

-      "#Calculations\n",

-      "phi=math.degrees(math.atan(X_L/R))\n",

-      "b=0\n",

-      "i=1\n",

-      "while (i>0) :\n",

-      "    LHS=math.sin(math.radians(b-a))\n",

-      "    RHS=math.sin(math.radians(a-phi))*math.exp(-(R/X_L)*(b-a)*math.pi/180)\n",

-      "    if math.fabs(LHS-RHS)<= 0.01 :\n",

-      "        B=b\n",

-      "        i=2\n",

-      "        break\n",

-      "   \n",

-      "    b=b+.1   \n",

-      "V_or=math.sqrt(2)*V*math.sqrt((1/(2*math.pi))*((B-a)*math.pi/180+(math.sin(math.radians(2*a))-math.sin(math.radians(2*B)))/2))\n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"Extinction angle=%.1f deg\" %B) #answer in the book is wrong as formulae for RHS is wrongly employed\n",

-      "print(\"rms value of output voltage=%.2f V\" %V_or) #answer do not match due to wrong B in book\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Extinction angle=156.1 deg\n",

-        "rms value of output voltage=97.75 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 6

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 9.8, Page No 581"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "a=60.0\n",

-      "R=20.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_or=math.sqrt((V_m**2/(2*math.pi))*(a*math.pi/180-math.sin(math.radians(2*a))/2)+(2*V_m**2/(math.pi))*(math.pi-a*math.pi/180+math.sin(math.radians(2*a))/2))    \n",

-      "I_T1r=(V_m/R)*math.sqrt(1/math.pi*((math.pi-a*math.pi/180)+math.sin(math.radians(2*a))/2))    \n",

-      "I_T3r=(V_m/(2*R))*math.sqrt(1/math.pi*((a*math.pi/180)-math.sin(math.radians(2*a))/2))    \n",

-      "I1=math.sqrt(2)*I_T1r\n",

-      "I3=math.sqrt((math.sqrt(2)*I_T1r)**2+(math.sqrt(2)*I_T3r)**2)\n",

-      "r=V_s*(I1+I3)    \n",

-      "P_o=V_or**2/R\n",

-      "pf=P_o/r    \n",

-      "\n",

-      "#Results\n",

-      "print(\"rms value of o/p voltage=%.2f V\" %V_or)\n",

-      "print(\"rms value of current for upper thyristors=%.2f A\" %I_T1r)\n",

-      "print(\"rms value of current for lower thyristors=%.2f A\" %I_T3r)\n",

-      "print(\"t/f VA rating=%.2f VA\" %r)\n",

-      "print(\"i/p pf=%.2f\" %pf)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rms value of o/p voltage=424.94 V\n",

-        "rms value of current for upper thyristors=14.59 A\n",

-        "rms value of current for lower thyristors=3.60 A\n",

-        "t/f VA rating=9631.61 VA\n",

-        "i/p pf=0.94\n"

-       ]

-      }

-     ],

-     "prompt_number": 7

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Power_Electronics/Chapter9_2.ipynb b/_Power_Electronics/Chapter9_2.ipynb
deleted file mode 100755
index 052c4736..00000000
--- a/_Power_Electronics/Chapter9_2.ipynb
+++ /dev/null
@@ -1,388 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 09 : AC Voltage Controllers"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 9.1, Page No 560"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "a=45.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_or=(V_m/2)*math.sqrt(1/math.pi*((2*math.pi-a*math.pi/180)+math.sin(math.radians(2*a))/2))    \n",

-      "R=20\n",

-      "I_or=V_or/R\n",

-      "P_o=I_or**2*R    \n",

-      "I_s=I_or\n",

-      "VA=V_s*I_s\n",

-      "pf=P_o/VA    \n",

-      "V_o=math.sqrt(2)*V_s/(2*math.pi)*(math.cos(math.radians(a))-1)\n",

-      "I_ON=V_o/R  \n",

-      "\n",

-      "#Results\n",

-      "print(\"rms value of o/p voltage=%.3f V\" %V_or)\n",

-      "print(\"load power=%.1f W\" %P_o)\n",

-      "print(\"i/p pf=%.4f\" %pf)\n",

-      "print(\"avg i/p current=%.4f A\" %I_ON)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rms value of o/p voltage=224.716 V\n",

-        "load power=2524.9 W\n",

-        "i/p pf=0.9770\n",

-        "avg i/p current=-0.7581 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 9.2, Page No 560"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "a=45.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_or=(V_s)*math.sqrt(1/math.pi*((math.pi-a*math.pi/180)+math.sin(math.radians(2*a))/2))    \n",

-      "R=20\n",

-      "I_or=V_or/R\n",

-      "P_o=I_or**2*R    \n",

-      "I_s=I_or\n",

-      "VA=V_s*I_s\n",

-      "pf=P_o/VA    \n",

-      "I_TA=math.sqrt(2)*V_s/(2*math.pi*R)*(math.cos(math.radians(a))+1)   \n",

-      "I_Tr=math.sqrt(2)*V_s/(2*R)*math.sqrt(1/math.pi*((math.pi-a*math.pi/180)+math.sin(math.radians(2*a))/2)) \n",

-      "\n",

-      "#Results\n",

-      "print(\"rms value of o/p voltage=%.3f V\" %V_or)\n",

-      "print(\"load power=%.2f W\" %P_o)\n",

-      "print(\"i/p pf=%.2f\" %pf)\n",

-      "print(\"avg thyristor current=%.2f A\" %I_TA)   \n",

-      "print(\"rms value of thyristor current=%.2f A\" %I_Tr)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rms value of o/p voltage=219.304 V\n",

-        "load power=2404.71 W\n",

-        "i/p pf=0.95\n",

-        "avg thyristor current=4.42 A\n",

-        "rms value of thyristor current=7.75 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 2

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 9.3 Page No 564"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "n=6.0 #on cycles\n",

-      "m=4.0 #off cycles\n",

-      "\n",

-      "#Calculations\n",

-      "k=n/(n+m)\n",

-      "V_or=V_s*math.sqrt(k)    \n",

-      "pf=math.sqrt(k)    \n",

-      "R=15\n",

-      "I_m=V_s*math.sqrt(2)/R\n",

-      "I_TA=k*I_m/math.pi\n",

-      "I_TR=I_m*math.sqrt(k)/2  \n",

-      "   \n",

-      "#Results\n",

-      "print(\"rms value of o/ voltage=%.2f V\" %V_or)\n",

-      "print(\"i/p pf=%.2f\" %pf)\n",

-      "print(\"avg thyristor current=%.2f A\" %I_TA)  \n",

-      "print(\"rms value of thyristor current=%.2f A\" %I_TR)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rms value of o/ voltage=178.16 V\n",

-        "i/p pf=0.77\n",

-        "avg thyristor current=4.14 A\n",

-        "rms value of thyristor current=8.40 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 3

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 9.4, Page No 569"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "R=3.0\n",

-      "\n",

-      "#Calculations\n",

-      "I_TAM1=2*V_m/(2*math.pi*R)  \n",

-      "I_TRM2=V_m/(2*R)    \n",

-      "f=50\n",

-      "w=2*math.pi*f\n",

-      "t_c=math.pi/w    \n",

-      " \n",

-      "#Results\n",

-      "print(\"max value of avg thyristor current=%.3f A\" %I_TAM1)\n",

-      "print(\"max value of avg thyristor current=%.3f A\" %I_TRM2)\n",

-      "print(\"ckt turn off time=%.0f ms\" %(t_c*1000))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "max value of avg thyristor current=34.512 A\n",

-        "max value of avg thyristor current=54.212 A\n",

-        "ckt turn off time=10 ms\n"

-       ]

-      }

-     ],

-     "prompt_number": 4

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 9.5 Page No 575"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "R=3.0\n",

-      "X_L=4.0\n",

-      "\n",

-      "#Calculations\n",

-      "phi=math.degrees(math.atan(X_L/R))    \n",

-      "V_s=230\n",

-      "Z=math.sqrt(R**2+X_L**2)\n",

-      "I_or=V_s/Z    \n",

-      "P=I_or**2*R    \n",

-      "I_s=I_or\n",

-      "pf=P/(V_s*I_s)    \n",

-      "I_TAM=math.sqrt(2)*V_s/(math.pi*Z)    \n",

-      "I_Tm=math.sqrt(2)*V_s/(2*Z)    \n",

-      "f=50\n",

-      "w=2*math.pi*f\n",

-      "di=math.sqrt(2)*V_s*w/Z    \n",

-      "\n",

-      "#Results\n",

-      "print(\"min firing angle=%.2f deg\" %phi)\n",

-      "print(\"\\nmax firing angle=%.0f deg\" %180)\n",

-      "print(\"i/p pf=%.1f\" %pf)\n",

-      "print(\"max value of rms load current=%.0f A\" %I_or)\n",

-      "print(\"max power=%.0f W\" %P)\n",

-      "print(\"max value of avg thyristor current=%.3f A\" %I_TAM)\n",

-      "print(\"max value of rms thyristor current=%.3f A\" %I_Tm)\n",

-      "print(\"di/dt=%.0f A/s\" %di)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "min firing angle=53.13 deg\n",

-        "\n",

-        "max firing angle=180 deg\n",

-        "i/p pf=0.6\n",

-        "max value of rms load current=46 A\n",

-        "max power=6348 W\n",

-        "max value of avg thyristor current=20.707 A\n",

-        "max value of rms thyristor current=32.527 A\n",

-        "di/dt=20437 A/s\n"

-       ]

-      }

-     ],

-     "prompt_number": 5

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 9.6 Page No 576"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=230.0\n",

-      "R=3.0 #ohm\n",

-      "X_L=5.0 #ohm\n",

-      "a=120.0 #firing angle delay\n",

-      "\n",

-      "#Calculations\n",

-      "phi=math.degrees(math.atan(X_L/R))\n",

-      "b=0\n",

-      "i=1\n",

-      "while (i>0) :\n",

-      "    LHS=math.sin(math.radians(b-a))\n",

-      "    RHS=math.sin(math.radians(a-phi))*math.exp(-(R/X_L)*(b-a)*math.pi/180)\n",

-      "    if math.fabs(LHS-RHS)<= 0.01 :\n",

-      "        B=b\n",

-      "        i=2\n",

-      "        break\n",

-      "   \n",

-      "    b=b+.1   \n",

-      "V_or=math.sqrt(2)*V*math.sqrt((1/(2*math.pi))*((B-a)*math.pi/180+(math.sin(math.radians(2*a))-math.sin(math.radians(2*B)))/2))\n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"Extinction angle=%.1f deg\" %B) #answer in the book is wrong as formulae for RHS is wrongly employed\n",

-      "print(\"rms value of output voltage=%.2f V\" %V_or) #answer do not match due to wrong B in book\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Extinction angle=156.1 deg\n",

-        "rms value of output voltage=97.75 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 6

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 9.8, Page No 581"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "a=60.0\n",

-      "R=20.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_or=math.sqrt((V_m**2/(2*math.pi))*(a*math.pi/180-math.sin(math.radians(2*a))/2)+(2*V_m**2/(math.pi))*(math.pi-a*math.pi/180+math.sin(math.radians(2*a))/2))    \n",

-      "I_T1r=(V_m/R)*math.sqrt(1/math.pi*((math.pi-a*math.pi/180)+math.sin(math.radians(2*a))/2))    \n",

-      "I_T3r=(V_m/(2*R))*math.sqrt(1/math.pi*((a*math.pi/180)-math.sin(math.radians(2*a))/2))    \n",

-      "I1=math.sqrt(2)*I_T1r\n",

-      "I3=math.sqrt((math.sqrt(2)*I_T1r)**2+(math.sqrt(2)*I_T3r)**2)\n",

-      "r=V_s*(I1+I3)    \n",

-      "P_o=V_or**2/R\n",

-      "pf=P_o/r    \n",

-      "\n",

-      "#Results\n",

-      "print(\"rms value of o/p voltage=%.2f V\" %V_or)\n",

-      "print(\"rms value of current for upper thyristors=%.2f A\" %I_T1r)\n",

-      "print(\"rms value of current for lower thyristors=%.2f A\" %I_T3r)\n",

-      "print(\"t/f VA rating=%.2f VA\" %r)\n",

-      "print(\"i/p pf=%.2f\" %pf)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rms value of o/p voltage=424.94 V\n",

-        "rms value of current for upper thyristors=14.59 A\n",

-        "rms value of current for lower thyristors=3.60 A\n",

-        "t/f VA rating=9631.61 VA\n",

-        "i/p pf=0.94\n"

-       ]

-      }

-     ],

-     "prompt_number": 7

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Power_Electronics/Chapter9_3.ipynb b/_Power_Electronics/Chapter9_3.ipynb
deleted file mode 100755
index 052c4736..00000000
--- a/_Power_Electronics/Chapter9_3.ipynb
+++ /dev/null
@@ -1,388 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 09 : AC Voltage Controllers"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 9.1, Page No 560"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "a=45.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_or=(V_m/2)*math.sqrt(1/math.pi*((2*math.pi-a*math.pi/180)+math.sin(math.radians(2*a))/2))    \n",

-      "R=20\n",

-      "I_or=V_or/R\n",

-      "P_o=I_or**2*R    \n",

-      "I_s=I_or\n",

-      "VA=V_s*I_s\n",

-      "pf=P_o/VA    \n",

-      "V_o=math.sqrt(2)*V_s/(2*math.pi)*(math.cos(math.radians(a))-1)\n",

-      "I_ON=V_o/R  \n",

-      "\n",

-      "#Results\n",

-      "print(\"rms value of o/p voltage=%.3f V\" %V_or)\n",

-      "print(\"load power=%.1f W\" %P_o)\n",

-      "print(\"i/p pf=%.4f\" %pf)\n",

-      "print(\"avg i/p current=%.4f A\" %I_ON)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rms value of o/p voltage=224.716 V\n",

-        "load power=2524.9 W\n",

-        "i/p pf=0.9770\n",

-        "avg i/p current=-0.7581 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 9.2, Page No 560"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "a=45.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_or=(V_s)*math.sqrt(1/math.pi*((math.pi-a*math.pi/180)+math.sin(math.radians(2*a))/2))    \n",

-      "R=20\n",

-      "I_or=V_or/R\n",

-      "P_o=I_or**2*R    \n",

-      "I_s=I_or\n",

-      "VA=V_s*I_s\n",

-      "pf=P_o/VA    \n",

-      "I_TA=math.sqrt(2)*V_s/(2*math.pi*R)*(math.cos(math.radians(a))+1)   \n",

-      "I_Tr=math.sqrt(2)*V_s/(2*R)*math.sqrt(1/math.pi*((math.pi-a*math.pi/180)+math.sin(math.radians(2*a))/2)) \n",

-      "\n",

-      "#Results\n",

-      "print(\"rms value of o/p voltage=%.3f V\" %V_or)\n",

-      "print(\"load power=%.2f W\" %P_o)\n",

-      "print(\"i/p pf=%.2f\" %pf)\n",

-      "print(\"avg thyristor current=%.2f A\" %I_TA)   \n",

-      "print(\"rms value of thyristor current=%.2f A\" %I_Tr)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rms value of o/p voltage=219.304 V\n",

-        "load power=2404.71 W\n",

-        "i/p pf=0.95\n",

-        "avg thyristor current=4.42 A\n",

-        "rms value of thyristor current=7.75 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 2

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 9.3 Page No 564"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "n=6.0 #on cycles\n",

-      "m=4.0 #off cycles\n",

-      "\n",

-      "#Calculations\n",

-      "k=n/(n+m)\n",

-      "V_or=V_s*math.sqrt(k)    \n",

-      "pf=math.sqrt(k)    \n",

-      "R=15\n",

-      "I_m=V_s*math.sqrt(2)/R\n",

-      "I_TA=k*I_m/math.pi\n",

-      "I_TR=I_m*math.sqrt(k)/2  \n",

-      "   \n",

-      "#Results\n",

-      "print(\"rms value of o/ voltage=%.2f V\" %V_or)\n",

-      "print(\"i/p pf=%.2f\" %pf)\n",

-      "print(\"avg thyristor current=%.2f A\" %I_TA)  \n",

-      "print(\"rms value of thyristor current=%.2f A\" %I_TR)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rms value of o/ voltage=178.16 V\n",

-        "i/p pf=0.77\n",

-        "avg thyristor current=4.14 A\n",

-        "rms value of thyristor current=8.40 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 3

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 9.4, Page No 569"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "R=3.0\n",

-      "\n",

-      "#Calculations\n",

-      "I_TAM1=2*V_m/(2*math.pi*R)  \n",

-      "I_TRM2=V_m/(2*R)    \n",

-      "f=50\n",

-      "w=2*math.pi*f\n",

-      "t_c=math.pi/w    \n",

-      " \n",

-      "#Results\n",

-      "print(\"max value of avg thyristor current=%.3f A\" %I_TAM1)\n",

-      "print(\"max value of avg thyristor current=%.3f A\" %I_TRM2)\n",

-      "print(\"ckt turn off time=%.0f ms\" %(t_c*1000))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "max value of avg thyristor current=34.512 A\n",

-        "max value of avg thyristor current=54.212 A\n",

-        "ckt turn off time=10 ms\n"

-       ]

-      }

-     ],

-     "prompt_number": 4

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 9.5 Page No 575"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "R=3.0\n",

-      "X_L=4.0\n",

-      "\n",

-      "#Calculations\n",

-      "phi=math.degrees(math.atan(X_L/R))    \n",

-      "V_s=230\n",

-      "Z=math.sqrt(R**2+X_L**2)\n",

-      "I_or=V_s/Z    \n",

-      "P=I_or**2*R    \n",

-      "I_s=I_or\n",

-      "pf=P/(V_s*I_s)    \n",

-      "I_TAM=math.sqrt(2)*V_s/(math.pi*Z)    \n",

-      "I_Tm=math.sqrt(2)*V_s/(2*Z)    \n",

-      "f=50\n",

-      "w=2*math.pi*f\n",

-      "di=math.sqrt(2)*V_s*w/Z    \n",

-      "\n",

-      "#Results\n",

-      "print(\"min firing angle=%.2f deg\" %phi)\n",

-      "print(\"\\nmax firing angle=%.0f deg\" %180)\n",

-      "print(\"i/p pf=%.1f\" %pf)\n",

-      "print(\"max value of rms load current=%.0f A\" %I_or)\n",

-      "print(\"max power=%.0f W\" %P)\n",

-      "print(\"max value of avg thyristor current=%.3f A\" %I_TAM)\n",

-      "print(\"max value of rms thyristor current=%.3f A\" %I_Tm)\n",

-      "print(\"di/dt=%.0f A/s\" %di)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "min firing angle=53.13 deg\n",

-        "\n",

-        "max firing angle=180 deg\n",

-        "i/p pf=0.6\n",

-        "max value of rms load current=46 A\n",

-        "max power=6348 W\n",

-        "max value of avg thyristor current=20.707 A\n",

-        "max value of rms thyristor current=32.527 A\n",

-        "di/dt=20437 A/s\n"

-       ]

-      }

-     ],

-     "prompt_number": 5

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 9.6 Page No 576"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=230.0\n",

-      "R=3.0 #ohm\n",

-      "X_L=5.0 #ohm\n",

-      "a=120.0 #firing angle delay\n",

-      "\n",

-      "#Calculations\n",

-      "phi=math.degrees(math.atan(X_L/R))\n",

-      "b=0\n",

-      "i=1\n",

-      "while (i>0) :\n",

-      "    LHS=math.sin(math.radians(b-a))\n",

-      "    RHS=math.sin(math.radians(a-phi))*math.exp(-(R/X_L)*(b-a)*math.pi/180)\n",

-      "    if math.fabs(LHS-RHS)<= 0.01 :\n",

-      "        B=b\n",

-      "        i=2\n",

-      "        break\n",

-      "   \n",

-      "    b=b+.1   \n",

-      "V_or=math.sqrt(2)*V*math.sqrt((1/(2*math.pi))*((B-a)*math.pi/180+(math.sin(math.radians(2*a))-math.sin(math.radians(2*B)))/2))\n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"Extinction angle=%.1f deg\" %B) #answer in the book is wrong as formulae for RHS is wrongly employed\n",

-      "print(\"rms value of output voltage=%.2f V\" %V_or) #answer do not match due to wrong B in book\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Extinction angle=156.1 deg\n",

-        "rms value of output voltage=97.75 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 6

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 9.8, Page No 581"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "a=60.0\n",

-      "R=20.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_or=math.sqrt((V_m**2/(2*math.pi))*(a*math.pi/180-math.sin(math.radians(2*a))/2)+(2*V_m**2/(math.pi))*(math.pi-a*math.pi/180+math.sin(math.radians(2*a))/2))    \n",

-      "I_T1r=(V_m/R)*math.sqrt(1/math.pi*((math.pi-a*math.pi/180)+math.sin(math.radians(2*a))/2))    \n",

-      "I_T3r=(V_m/(2*R))*math.sqrt(1/math.pi*((a*math.pi/180)-math.sin(math.radians(2*a))/2))    \n",

-      "I1=math.sqrt(2)*I_T1r\n",

-      "I3=math.sqrt((math.sqrt(2)*I_T1r)**2+(math.sqrt(2)*I_T3r)**2)\n",

-      "r=V_s*(I1+I3)    \n",

-      "P_o=V_or**2/R\n",

-      "pf=P_o/r    \n",

-      "\n",

-      "#Results\n",

-      "print(\"rms value of o/p voltage=%.2f V\" %V_or)\n",

-      "print(\"rms value of current for upper thyristors=%.2f A\" %I_T1r)\n",

-      "print(\"rms value of current for lower thyristors=%.2f A\" %I_T3r)\n",

-      "print(\"t/f VA rating=%.2f VA\" %r)\n",

-      "print(\"i/p pf=%.2f\" %pf)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rms value of o/p voltage=424.94 V\n",

-        "rms value of current for upper thyristors=14.59 A\n",

-        "rms value of current for lower thyristors=3.60 A\n",

-        "t/f VA rating=9631.61 VA\n",

-        "i/p pf=0.94\n"

-       ]

-      }

-     ],

-     "prompt_number": 7

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Power_Electronics/Chapter9_4.ipynb b/_Power_Electronics/Chapter9_4.ipynb
deleted file mode 100755
index 052c4736..00000000
--- a/_Power_Electronics/Chapter9_4.ipynb
+++ /dev/null
@@ -1,388 +0,0 @@
-{

- "metadata": {

-  "name": ""

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter 09 : AC Voltage Controllers"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 9.1, Page No 560"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "a=45.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_or=(V_m/2)*math.sqrt(1/math.pi*((2*math.pi-a*math.pi/180)+math.sin(math.radians(2*a))/2))    \n",

-      "R=20\n",

-      "I_or=V_or/R\n",

-      "P_o=I_or**2*R    \n",

-      "I_s=I_or\n",

-      "VA=V_s*I_s\n",

-      "pf=P_o/VA    \n",

-      "V_o=math.sqrt(2)*V_s/(2*math.pi)*(math.cos(math.radians(a))-1)\n",

-      "I_ON=V_o/R  \n",

-      "\n",

-      "#Results\n",

-      "print(\"rms value of o/p voltage=%.3f V\" %V_or)\n",

-      "print(\"load power=%.1f W\" %P_o)\n",

-      "print(\"i/p pf=%.4f\" %pf)\n",

-      "print(\"avg i/p current=%.4f A\" %I_ON)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rms value of o/p voltage=224.716 V\n",

-        "load power=2524.9 W\n",

-        "i/p pf=0.9770\n",

-        "avg i/p current=-0.7581 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 9.2, Page No 560"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "a=45.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_or=(V_s)*math.sqrt(1/math.pi*((math.pi-a*math.pi/180)+math.sin(math.radians(2*a))/2))    \n",

-      "R=20\n",

-      "I_or=V_or/R\n",

-      "P_o=I_or**2*R    \n",

-      "I_s=I_or\n",

-      "VA=V_s*I_s\n",

-      "pf=P_o/VA    \n",

-      "I_TA=math.sqrt(2)*V_s/(2*math.pi*R)*(math.cos(math.radians(a))+1)   \n",

-      "I_Tr=math.sqrt(2)*V_s/(2*R)*math.sqrt(1/math.pi*((math.pi-a*math.pi/180)+math.sin(math.radians(2*a))/2)) \n",

-      "\n",

-      "#Results\n",

-      "print(\"rms value of o/p voltage=%.3f V\" %V_or)\n",

-      "print(\"load power=%.2f W\" %P_o)\n",

-      "print(\"i/p pf=%.2f\" %pf)\n",

-      "print(\"avg thyristor current=%.2f A\" %I_TA)   \n",

-      "print(\"rms value of thyristor current=%.2f A\" %I_Tr)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rms value of o/p voltage=219.304 V\n",

-        "load power=2404.71 W\n",

-        "i/p pf=0.95\n",

-        "avg thyristor current=4.42 A\n",

-        "rms value of thyristor current=7.75 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 2

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 9.3 Page No 564"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "n=6.0 #on cycles\n",

-      "m=4.0 #off cycles\n",

-      "\n",

-      "#Calculations\n",

-      "k=n/(n+m)\n",

-      "V_or=V_s*math.sqrt(k)    \n",

-      "pf=math.sqrt(k)    \n",

-      "R=15\n",

-      "I_m=V_s*math.sqrt(2)/R\n",

-      "I_TA=k*I_m/math.pi\n",

-      "I_TR=I_m*math.sqrt(k)/2  \n",

-      "   \n",

-      "#Results\n",

-      "print(\"rms value of o/ voltage=%.2f V\" %V_or)\n",

-      "print(\"i/p pf=%.2f\" %pf)\n",

-      "print(\"avg thyristor current=%.2f A\" %I_TA)  \n",

-      "print(\"rms value of thyristor current=%.2f A\" %I_TR)\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rms value of o/ voltage=178.16 V\n",

-        "i/p pf=0.77\n",

-        "avg thyristor current=4.14 A\n",

-        "rms value of thyristor current=8.40 A\n"

-       ]

-      }

-     ],

-     "prompt_number": 3

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 9.4, Page No 569"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "R=3.0\n",

-      "\n",

-      "#Calculations\n",

-      "I_TAM1=2*V_m/(2*math.pi*R)  \n",

-      "I_TRM2=V_m/(2*R)    \n",

-      "f=50\n",

-      "w=2*math.pi*f\n",

-      "t_c=math.pi/w    \n",

-      " \n",

-      "#Results\n",

-      "print(\"max value of avg thyristor current=%.3f A\" %I_TAM1)\n",

-      "print(\"max value of avg thyristor current=%.3f A\" %I_TRM2)\n",

-      "print(\"ckt turn off time=%.0f ms\" %(t_c*1000))"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "max value of avg thyristor current=34.512 A\n",

-        "max value of avg thyristor current=54.212 A\n",

-        "ckt turn off time=10 ms\n"

-       ]

-      }

-     ],

-     "prompt_number": 4

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 9.5 Page No 575"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "R=3.0\n",

-      "X_L=4.0\n",

-      "\n",

-      "#Calculations\n",

-      "phi=math.degrees(math.atan(X_L/R))    \n",

-      "V_s=230\n",

-      "Z=math.sqrt(R**2+X_L**2)\n",

-      "I_or=V_s/Z    \n",

-      "P=I_or**2*R    \n",

-      "I_s=I_or\n",

-      "pf=P/(V_s*I_s)    \n",

-      "I_TAM=math.sqrt(2)*V_s/(math.pi*Z)    \n",

-      "I_Tm=math.sqrt(2)*V_s/(2*Z)    \n",

-      "f=50\n",

-      "w=2*math.pi*f\n",

-      "di=math.sqrt(2)*V_s*w/Z    \n",

-      "\n",

-      "#Results\n",

-      "print(\"min firing angle=%.2f deg\" %phi)\n",

-      "print(\"\\nmax firing angle=%.0f deg\" %180)\n",

-      "print(\"i/p pf=%.1f\" %pf)\n",

-      "print(\"max value of rms load current=%.0f A\" %I_or)\n",

-      "print(\"max power=%.0f W\" %P)\n",

-      "print(\"max value of avg thyristor current=%.3f A\" %I_TAM)\n",

-      "print(\"max value of rms thyristor current=%.3f A\" %I_Tm)\n",

-      "print(\"di/dt=%.0f A/s\" %di)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "min firing angle=53.13 deg\n",

-        "\n",

-        "max firing angle=180 deg\n",

-        "i/p pf=0.6\n",

-        "max value of rms load current=46 A\n",

-        "max power=6348 W\n",

-        "max value of avg thyristor current=20.707 A\n",

-        "max value of rms thyristor current=32.527 A\n",

-        "di/dt=20437 A/s\n"

-       ]

-      }

-     ],

-     "prompt_number": 5

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 9.6 Page No 576"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V=230.0\n",

-      "R=3.0 #ohm\n",

-      "X_L=5.0 #ohm\n",

-      "a=120.0 #firing angle delay\n",

-      "\n",

-      "#Calculations\n",

-      "phi=math.degrees(math.atan(X_L/R))\n",

-      "b=0\n",

-      "i=1\n",

-      "while (i>0) :\n",

-      "    LHS=math.sin(math.radians(b-a))\n",

-      "    RHS=math.sin(math.radians(a-phi))*math.exp(-(R/X_L)*(b-a)*math.pi/180)\n",

-      "    if math.fabs(LHS-RHS)<= 0.01 :\n",

-      "        B=b\n",

-      "        i=2\n",

-      "        break\n",

-      "   \n",

-      "    b=b+.1   \n",

-      "V_or=math.sqrt(2)*V*math.sqrt((1/(2*math.pi))*((B-a)*math.pi/180+(math.sin(math.radians(2*a))-math.sin(math.radians(2*B)))/2))\n",

-      "\n",

-      "\n",

-      "#Results\n",

-      "print(\"Extinction angle=%.1f deg\" %B) #answer in the book is wrong as formulae for RHS is wrongly employed\n",

-      "print(\"rms value of output voltage=%.2f V\" %V_or) #answer do not match due to wrong B in book\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Extinction angle=156.1 deg\n",

-        "rms value of output voltage=97.75 V\n"

-       ]

-      }

-     ],

-     "prompt_number": 6

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Example 9.8, Page No 581"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "import math\n",

-      "#initialisation of variables\n",

-      "V_s=230.0\n",

-      "V_m=math.sqrt(2)*V_s\n",

-      "a=60.0\n",

-      "R=20.0\n",

-      "\n",

-      "#Calculations\n",

-      "V_or=math.sqrt((V_m**2/(2*math.pi))*(a*math.pi/180-math.sin(math.radians(2*a))/2)+(2*V_m**2/(math.pi))*(math.pi-a*math.pi/180+math.sin(math.radians(2*a))/2))    \n",

-      "I_T1r=(V_m/R)*math.sqrt(1/math.pi*((math.pi-a*math.pi/180)+math.sin(math.radians(2*a))/2))    \n",

-      "I_T3r=(V_m/(2*R))*math.sqrt(1/math.pi*((a*math.pi/180)-math.sin(math.radians(2*a))/2))    \n",

-      "I1=math.sqrt(2)*I_T1r\n",

-      "I3=math.sqrt((math.sqrt(2)*I_T1r)**2+(math.sqrt(2)*I_T3r)**2)\n",

-      "r=V_s*(I1+I3)    \n",

-      "P_o=V_or**2/R\n",

-      "pf=P_o/r    \n",

-      "\n",

-      "#Results\n",

-      "print(\"rms value of o/p voltage=%.2f V\" %V_or)\n",

-      "print(\"rms value of current for upper thyristors=%.2f A\" %I_T1r)\n",

-      "print(\"rms value of current for lower thyristors=%.2f A\" %I_T3r)\n",

-      "print(\"t/f VA rating=%.2f VA\" %r)\n",

-      "print(\"i/p pf=%.2f\" %pf)"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "rms value of o/p voltage=424.94 V\n",

-        "rms value of current for upper thyristors=14.59 A\n",

-        "rms value of current for lower thyristors=3.60 A\n",

-        "t/f VA rating=9631.61 VA\n",

-        "i/p pf=0.94\n"

-       ]

-      }

-     ],

-     "prompt_number": 7

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
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diff --git a/_Theory_Of_Machines/Chapter1.ipynb b/_Theory_Of_Machines/Chapter1.ipynb
deleted file mode 100755
index 1c82cdeb..00000000
--- a/_Theory_Of_Machines/Chapter1.ipynb
+++ /dev/null
@@ -1,663 +0,0 @@
-{

- "metadata": {

-  "name": "",

-  "signature": "sha256:33bb604c38fad316310d35481ce37e53ae0ade845d03c72c1ef523c0dcf5fe56"

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter1-Basic Kinematics"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex1-pg15"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 1 ILLUSRTATION 1 PAGE NO 15\n",

-      "#calculate inclination of slotted bar with vertical \n",

-      "##TITLE:Basic kinematics\n",

-      "##Figure 1.14\n",

-      "import math\n",

-      "pi=3.141\n",

-      "AO=200.##                 distance between fixed centres in mm\n",

-      "OB1=100.##                length of driving crank in mm\n",

-      "AP=400.##                 length of slotter bar in mm\n",

-      "##====================================\n",

-      "OAB1=math.asin(OB1/AO)*57.3##              inclination of slotted bar with vertical in degrees\n",

-      "beeta=(90-OAB1)*2.##               angle through which crank turns inreturn stroke in degrees\n",

-      "A=(360.-beeta)/beeta##             ratio of time of cutting stroke to the time of return stroke \n",

-      "L=2.*AP*math.sin(90.-beeta/2.)/57.3##       length of the stroke in mm\n",

-      "print'%s %.2f %s %.3f %s'%('Inclination of slotted bar with vertical= ',OAB1,' degrees' 'Length of the stroke=',L,' mm')\n",

-      "\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Inclination of slotted bar with vertical=  30.00  degreesLength of the stroke= -13.790  mm\n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex2-pg16"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 1 ILLUSRTATION 2 PAGE NO 16\n",

-      "#calculate ratio of time taken on the cutting to the return\n",

-      "##TITLE:Basic kinematics\n",

-      "##Figure 1.15\n",

-      "import math\n",

-      "OA=300.##               distance between the fixed centres in mm\n",

-      "OB=150.##                 length of driving crank in mm\n",

-      "##================================\n",

-      "OAB=math.asin(OB/OA)##              inclination of slotted bar with vertical in degrees\n",

-      "beeta=(90/57.3-OAB)*2.##               angle through which crank turns inreturn stroke in degrees\n",

-      "A=(360/57.3-beeta)/beeta##             ratio of time of cutting stroke to the time of return stroke \n",

-      "print'%s %.1f %s'%('Ratio of time taken on the cutting to the return stroke= ',A,'')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Ratio of time taken on the cutting to the return stroke=  2.0 \n"

-       ]

-      }

-     ],

-     "prompt_number": 2

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex3-pg16"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 1 ILLUSRTATION 3 PAGE NO 16\n",

-      "#calculate ratio of time taken on the cutting to the return stroke \n",

-      "##TITLE:Basic kinematics\n",

-      "##Figure 1.16\n",

-      "import math\n",

-      "OB=54.6/57.3##               distance between the fixed centres in mm\n",

-      "OA=85./57.3##                 length of driving crank in mm\n",

-      "OA2=OA\n",

-      "CA=160.##                length of slotted lever in mm\n",

-      "CD=144.##                length of connectin rod in mm\n",

-      "##================================\n",

-      "beeta=2.*(math.cos(OB/OA2))##        angle through which crank turns inreturn stroke in degrees\n",

-      "A=(360/57.3-beeta)/beeta##             ratio of time of cutting stroke to the time of return stroke \n",

-      "print'%s %.1f %s'%('Ratio of time taken on the cutting to the return stroke= ',A,'')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Ratio of time taken on the cutting to the return stroke=  2.9 \n"

-       ]

-      }

-     ],

-     "prompt_number": 3

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex4-pg 17"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 1 ILLUSRTATION 4 PAGE NO 17\n",

-      "#calculate velocity position and Angular velocity connection\n",

-      "##TITLE:Basic kinematics\n",

-      "##Figure 1.18,1.19\n",

-      "import math\n",

-      "pi=3.141\n",

-      "Nao=180.##     speed of the crank in rpm\n",

-      "wAO=2.*pi*Nao/60.##  angular speed of the crank in rad/s\n",

-      "AO=.5##          crank length in m\n",

-      "AE=.5\n",

-      "Vao=wAO*AO##      velocity of A in m/s\n",

-      "##================================\n",

-      "Vb1=8.15##    velocity of piston B in m/s by measurment from figure 1.19\n",

-      "Vba=6.8##    velocity of B with respect to A in m/s\n",

-      "AB=2##       length of connecting rod in m\n",

-      "wBA=Vba/AB##      angular velocity of the connecting rod BA in rad/s\n",

-      "ae=AE*Vba/AB##     velocity of point e on the connecting rod\n",

-      "oe=8.5##           by measurement velocity of point E\n",

-      "Do=.05##           diameter of crank shaft in m\n",

-      "Da=.06##           diameter of crank pin in m\n",

-      "Db=.03##           diameter of cross head pin B m\n",

-      "V1=wAO*Do/2.##            velocity of rubbing at the pin of the crankshaft in m/s\n",

-      "V2=wBA*Da/2.##            velocity of rubbing at the pin of the crank in m/s\n",

-      "Vb=(wAO+wBA)*Db/2.##      velocity of rubbing at the pin of cross head in m/s\n",

-      "ag=5.1##                by measurement\n",

-      "AG=AB*ag/Vba##      position and linear velocity of point G on the connecting rod in m\n",

-      "##===============================\n",

-      "print'%s %.3f %s %.3f %s %.3f %s %.3f %s %.3f %s %.3f %s %.3f %s'%('Velocity of piston B=',Vb1,' m/s''Angular velocity of connecting rod= ',wBA,' rad/s''velocity of point E=',oe,' m/s'' velocity of rubbing at the pin of the crankshaft=',V1,' m/s' 'velocity of rubbing at the pin of the crank =',V2,' m/s''velocity of rubbing at the pin of cross head =',Vb,' m/s''position and linear velocity of point G on the connecting rod=',AG,' m')\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      " \n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Velocity of piston B= 8.150  m/sAngular velocity of connecting rod=  3.400  rad/svelocity of point E= 8.500  m/s velocity of rubbing at the pin of the crankshaft= 0.471  m/svelocity of rubbing at the pin of the crank = 0.102  m/svelocity of rubbing at the pin of cross head = 0.334  m/sposition and linear velocity of point G on the connecting rod= 1.500  m\n"

-       ]

-      }

-     ],

-     "prompt_number": 4

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex5-pg 19"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 1 ILLUSRTATION 5 PAGE NO 19\n",

-      "#calculate linear velocity at various point\n",

-      "##TITLE:Basic kinematics\n",

-      "##Figure 1.20,1.21\n",

-      "import math\n",

-      "pi=3.141\n",

-      "N=120.##      speed of crank in rpm\n",

-      "OA=10.##      length of crank in cm\n",

-      "BP=48.##      from figure 1.20 in cm\n",

-      "BA=40.##      from figure 1.20 in cm\n",

-      "##==============\n",

-      "w=2.*pi*N/60.##       angular velocity of the crank OA in rad/s\n",

-      "Vao=w*OA##          velocity of ao in cm/s\n",

-      "ba=4.5##            by measurement from 1.21 in cm\n",

-      "Bp=BP*ba/BA\n",

-      "op=6.8##           by measurement in cm from figure 1.21\n",

-      "s=20.##              scale of velocity diagram 1cm=20cm/s\n",

-      "Vp=op*s##           linear velocity of P in m/s\n",

-      "ob=5.1##            by measurement in cm from figure 1.21\n",

-      "Vb=ob*s##           linear velocity of slider B\n",

-      "print'%s %.2f %s %.2f %s'%('Linear velocity of slider B= ',Vb,' cm/s''Linear velocity of point P= ',Vp,' cm/s')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Linear velocity of slider B=  102.00  cm/sLinear velocity of point P=  136.00  cm/s\n"

-       ]

-      }

-     ],

-     "prompt_number": 13

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex6-pg20"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "#calculate angular velocity at various points\n",

-      "##CHAPTER 1 ILLUSRTATION 6 PAGE NO 20\n",

-      "##TITLE:Basic kinematics\n",

-      "##Figure 1.22,1.23\n",

-      "import math\n",

-      "pi=3.141\n",

-      "AB=6.25##     length of link AB in cm\n",

-      "BC=17.5##     length of link BC in cm\n",

-      "CD=11.25##    length of link CD in cm\n",

-      "DA=20.##       length of link DA in cm\n",

-      "CE=10.\n",

-      "N=100.##       speed of crank in rpm\n",

-      "##========================\n",

-      "wAB=2.*pi*N/60.##      angular velocity of AB in rad/s\n",

-      "Vb=wAB*AB##          linear velocity of B with respect to A\n",

-      "s=15.##      scale for velocity diagram 1 cm= 15 cm/s\n",

-      "dc=3.##      by measurement in cm\n",

-      "Vcd=dc*s\n",

-      "wCD=Vcd/CD##       angular velocity of link CD in rad/s\n",

-      "bc=2.5##    by measurement in cm\n",

-      "Vbc=bc*s\n",

-      "wBC=Vbc/BC##     angular velocity of link BC in rad/s\n",

-      "ce=bc*CE/BC\n",

-      "ae=3.66##       by measurement in cm\n",

-      "Ve=ae*s##         velocity of point E 10 from c on the link BC\n",

-      "af=2.94##       by measurement in cm\n",

-      "Vf=af*s##       velocity of point F\n",

-      "print'%s %.3f %s %.3f %s %.3f %s %.3f %s'%('The angular velocity of link CD= ',wCD,' rad/s'' The angular velocity of link BC= ',wBC,'rad/s'' velocity of point E 10 from c on the link BC= ',Ve,' cm/s' ' velocity of point F= ',Vf,' cm/s')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "The angular velocity of link CD=  4.000  rad/s The angular velocity of link BC=  2.143 rad/s velocity of point E 10 from c on the link BC=  54.900  cm/s velocity of point F=  44.100  cm/s\n"

-       ]

-      }

-     ],

-     "prompt_number": 12

-    },

-    {

-     "cell_type": "heading",

-     "level": 3,

-     "metadata": {},

-     "source": [

-      "Ex7-pg21"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 1 ILLUSRTATION 7 PAGE NO 21\n",

-      "##TITLE:Basic kinematics\n",

-      "#calculate Linear velocity slider and angular velocity of link\n",

-      "##Figure 1.24,1.25\n",

-      "import math\n",

-      "pi=3.141\n",

-      "Noa=600##      speed of the crank in rpm\n",

-      "OA=2.8##       length of link OA in cm\n",

-      "AB=4.4##       length of link AB in cm\n",

-      "BC=4.9##       length of link BC in cm\n",

-      "BD=4.6##       length of link BD in cm\n",

-      "##=================\n",

-      "wOA=2.*pi*Noa/60.##        angular velocity of crank in rad/s\n",

-      "Vao=wOA*OA##             The linear velocity of point A with respect to oin m/s\n",

-      "s=50.##                   scale of velocity diagram in cm\n",

-      "od=2.95##              by measurement in cm from figure\n",

-      "Vd=od*s/100.##             linear velocity slider in m/s\n",

-      "bd=3.2##              by measurement in cm from figure\n",

-      "Vbd=bd*s\n",

-      "wBD=Vbd/BD##     angular velocity of link BD\n",

-      "print'%s %.1f %s %.1f %s '%('linear velocity slider D= ',Vd,' m/s' 'angular velocity of link BD= ',wBD,' rad/s')\n",

-      "\n",

-      "\n",

-      "\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "linear velocity slider D=  1.5  m/sangular velocity of link BD=  34.8  rad/s \n"

-       ]

-      }

-     ],

-     "prompt_number": 11

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex8-pg22"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 1 ILLUSRTATION 8 PAGE NO 22\n",

-      "#calculate Angular velocity of link CD\n",

-      "##TITLE:Basic kinematics\n",

-      "import math\n",

-      "pi=3.141\n",

-      "Noa=60.##        speed of crank in rpm\n",

-      "OA=30.##     length of link OA in cm\n",

-      "AB=100.##       length of link AB in cm\n",

-      "CD=80.##         length of link CD in cm\n",

-      "##AC=CB\n",

-      "##================\n",

-      "wOA=2.*pi*Noa/60.##     angular velocity of crank in rad/s\n",

-      "Vao=wOA*OA/100.##      linear velocity of point A with respect to O\n",

-      "s=50.##          scale for velocity diagram 1 cm= 50 cm/s\n",

-      "ob=3.4##        by measurement in cm from figure 1.27\n",

-      "od=.9##         by measurement in cm from figure 1.27\n",

-      "Vcd=160.##       by measurement in cm/s from figure 1.27\n",

-      "wCD=Vcd/CD##    angular velocity of link in rad/s\n",

-      "print'%s %.d %s'%('Angular velocity of link CD= ',wCD,' rad/s')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Angular velocity of link CD=  2  rad/s\n"

-       ]

-      }

-     ],

-     "prompt_number": 10

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex9-pg23"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 1 ILLUSRTATION 9 PAGE NO 23\n",

-      "#calculate velcity of Ram and anugular velocity of link and velocity of slidingof the block\n",

-      "##TITLE:Basic kinematics\n",

-      "##Figure 1.28,1.29\n",

-      "import math\n",

-      "pi=3.141\n",

-      "Nao=120.##            speed of the crank in rpm\n",

-      "OQ=10.##              length of link OQ in cm\n",

-      "OA=20.##              length of link OA in cm\n",

-      "QC=15.##              length of link QC in cm\n",

-      "CD=50.##              length oflink CD in cm\n",

-      "##=============\n",

-      "wOA=2.*pi*Nao/60.##      angular speed of crank in rad/s\n",

-      "Vad=wOA*OA/100.##         velocity of pin A in m/s\n",

-      "BQ=41.##               from figure 1.29 \n",

-      "BC=26.##               from firure 1.29 \n",

-      "bq=4.7##               from figure 1.29\n",

-      "bc=bq*BC/BQ##          from figure 1.29 in cm\n",

-      "s=50.##                 scale for velocity diagram in cm/s\n",

-      "od=1.525##             velocity vector od in cm from figure 1.29\n",

-      "Vd=od*s##              velocity of ram D in cm/s\n",

-      "dc=1.925##             velocity vector dc in cm from figure 1.29\n",

-      "Vdc=dc*s##             velocity of link CD in cm/s\n",

-      "wCD=Vdc/CD##           angular velocity of link CD in cm/s\n",

-      "ba=1.8##               velocity vector of sliding of the block in cm\n",

-      "Vab=ba*s##             velocity of sliding of the block in cm/s\n",

-      "print'%s %.3f %s %.2f %s %.1f %s '%('Velocity of RAM D= ',Vd,' cm/s''angular velocity of link CD= ',wCD,' rad/s'' velocity of sliding of the block= ',Vab,' cm/s')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Velocity of RAM D=  76.250  cm/sangular velocity of link CD=  1.93  rad/s velocity of sliding of the block=  90.0  cm/s \n"

-       ]

-      }

-     ],

-     "prompt_number": 9

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex10-pg24"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 1 ILLUSRTATION 10 PAGE NO 24\n",

-      "##TITLE:Basic kinematics\n",

-      "#calculate linear velocity abd radial component of accerlation and anugular velocity of connecting rod and anugular accerlation of connecting rod\n",

-      "##Figure 1.30(a),1.30(b),1.30(c)\n",

-      "import math\n",

-      "pi=3.141\n",

-      "Nao=300.##         speed of crank in rpm\n",

-      "AO=.15##          length of crank in m\n",

-      "BA=.6##           length of connecting rod in m\n",

-      "##===================\n",

-      "wAO=2.*pi*Nao/60.##        angular velocity of link in rad/s\n",

-      "Vao=wAO*AO##             linear velocity of A with respect to 'o'\n",

-      "ab=3.4##        length of vector ab by measurement in m/s\n",

-      "Vba=ab\n",

-      "ob=4.##        length of vector ob by measurement in m/s\n",

-      "oc=4.1##         length of vector oc by measurement in m/s\n",

-      "fRao=Vao**2./AO##    radial component of acceleration of A with respect to O\n",

-      "fRba=Vba**2./BA##     radial component of acceleration of B with respect to A\n",

-      "wBA=Vba/BA##        angular velocity of connecting rod BA\n",

-      "fTba=103.##         by measurement in m/s**2\n",

-      "alphaBA=fTba/BA##    angular acceleration of connecting rod BA\n",

-      "print'%s %.1f %s %.1f %s %.1f %s %.1f %s %.1f %s  '%('linear velocity of A with respect to O= ',Vao,' m/s''radial component of acceleration of A with respect to O= ',fRao,' m/s**2'' radial component of acceleration of B with respect to A=',fRba,' m/s**2'' angular velocity of connecting rod B= ',wBA,' rad/s'' angular acceleration of connecting rod BA= ',alphaBA,' rad/s**2')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "linear velocity of A with respect to O=  4.7  m/sradial component of acceleration of A with respect to O=  148.0  m/s**2 radial component of acceleration of B with respect to A= 19.3  m/s**2 angular velocity of connecting rod B=  5.7  rad/s angular acceleration of connecting rod BA=  171.7  rad/s**2  \n"

-       ]

-      }

-     ],

-     "prompt_number": 8

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex11-pg26"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 1 ILLUSRTATION 11 PAGE NO 26\n",

-      "#calcualte Angular accerlation at various point\n",

-      "##TITLE:Basic kinematics\n",

-      "##Figure 1.31(a),1.31(b),1.31(c)\n",

-      "import math\n",

-      "pi=3.141\n",

-      "wAP=10.##            angular velocity of crank in rad/s\n",

-      "P1A=30.##            length of link P1A in cm\n",

-      "P2B=36.##            length of link P2B in cm\n",

-      "AB=36.##             length of link AB in cm\n",

-      "P1P2=60.##           length of link P1P2 in cm\n",

-      "AP1P2=60.##          crank inclination in degrees \n",

-      "alphaP1A=30.##       angulare acceleration of crank P1A in rad/s**2\n",

-      "##=====================================\n",

-      "Vap1=wAP*P1A/100.##    linear velocity of A with respect to P1 in m/s\n",

-      "Vbp2=2.2##            velocity of B with respect to P2 in m/s(measured from figure )\n",

-      "Vba=2.06##            velocity of B with respect to A in m/s(measured from figure )\n",

-      "wBP2=Vbp2/(P2B*100.)##   angular velocity of P2B in rad/s\n",

-      "wAB=Vba/(AB*100.)##      angular velocity of AB in rad/s\n",

-      "fAB1=alphaP1A*P1A/100.##  tangential component of the acceleration of A with respect to P1 in m/s**2\n",

-      "frAB1=Vap1**2./(P1A/100.)##  radial component of the acceleration of A with respect to P1 in m/s**2\n",

-      "frBA=Vba**2./(AB/100.)##     radial component of the acceleration of B with respect to B in m/s**2\n",

-      "frBP2=Vbp2**2./(P2B/100.)##    radial component of the acceleration of B with respect to P2 in m/s**2\n",

-      "ftBA=13.62##             tangential component of B with respect to A in m/s**2(measured from figure)\n",

-      "ftBP2=26.62##            tangential component of B with respect to P2 in m/s**2(measured from figure)\n",

-      "alphaBP2=ftBP2/(P2B/100.)##   angular acceleration of P2B in m/s**2\n",

-      "alphaBA=ftBA/(AB/100.)##      angular acceleration of AB in m/s**2\n",

-      "##==========================\n",

-      "print'%s %.1f %s %.1f %s'%('Angular acceleration of P2B=',alphaBP2,' rad/s**2''angular acceleration of AB =',alphaBA,' rad/s**2')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Angular acceleration of P2B= 73.9  rad/s**2angular acceleration of AB = 37.8  rad/s**2\n"

-       ]

-      }

-     ],

-     "prompt_number": 6

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex12-pg28"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 1 ILLUSRTATION 12 PAGE NO 28\n",

-      "#calculate velocities at various point\n",

-      "##TITLE:Basic kinematics\n",

-      "##Figure 1.32(a),1.32(b),1.32(c)\n",

-      "import math\n",

-      "PI=3.141\n",

-      "AB=12.##    length of link AB in cm\n",

-      "BC=48.##    length of link BC in cm\n",

-      "CD=18.##    length of link CD in cm\n",

-      "DE=36.##    length of link DE in cm\n",

-      "EF=12.##    length of link EF in cm\n",

-      "FP=36.##    length of link FP in cm\n",

-      "Nba=200.##   roating speed of link BA IN rpm\n",

-      "wBA=2*PI*200./60.##    Angular velocity of BA in rad/s\n",

-      "Vba=wBA*AB/100.##    linear velocity of B with respect to A in m/s\n",

-      "Vc=2.428##   velocity of c in m/s from diagram 1.32(b)\n",

-      "Vd=2.36##     velocity of D in m/s from diagram 1.32(b)\n",

-      "Ve=1##    velocity of e in m/s from diagram 1.32(b)\n",

-      "Vf=1.42##    velocity of f in m/s from diagram 1.32(b)\n",

-      "Vcb=1.3##    velocity of c with respect to b in m/s from figure\n",

-      "fBA=Vba**2.*100./AB##   radial component of acceleration of B with respect to A in m/s**2\n",

-      "fCB=Vcb**2*100./BC##   radial component of acceleration of C with respect to B in m/s**2\n",

-      "fcb=3.52##          radial component of acceleration of C with respect to B in m/s**2 from figure\n",

-      "fC=19.##              acceleration of slider in m/s**2 from figure\n",

-      "print'%s %.1f %s %.1f %s %.1f %s %.2f %s %.2f %s'%('velocity of c=',Vc,' m/s''velocity of d=',Vd,' m/s''velocity of e=',Ve,' m/s'' velocity of f=',Vf,' m/s''Acceleration of slider=',Vc,' m/s**2')\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "velocity of c= 2.4  m/svelocity of d= 2.4  m/svelocity of e= 1.0  m/s velocity of f= 1.42  m/sAcceleration of slider= 2.43  m/s**2\n"

-       ]

-      }

-     ],

-     "prompt_number": 5

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex13-pg30"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 1 ILLUSRTATION 13 PAGE NO 30\n",

-      "#caculate angular acceleration at varoius points\n",

-      "##TITLE:Basic kinematics\n",

-      "##Figure 1.33(a),1.33(b),1.33(c)\n",

-      "import math\n",

-      "PI=3.141\n",

-      "N=120.##        speed of the crank OC in rpm\n",

-      "OC=5.##         length of link OC in cm\n",

-      "cp=20.##        length of link CP in cm\n",

-      "qa=10.##        length of link QA in cm\n",

-      "pa=5.##         length of link PA in cm\n",

-      "CP=46.9##        velocity of link CP in cm/s\n",

-      "QA=58.3##        velocity of link QA in cm/s\n",

-      "Pa=18.3##        velocity of link PA in cm/s\n",

-      "Vc=2.*PI*N*OC/60.##    velocity of C in m/s\n",

-      "Cco=Vc**2./OC##        centripetal acceleration of C relative to O in cm/s**2\n",

-      "Cpc=CP**2./cp##         centripetal acceleration of P relative to C in cm/s**2\n",

-      "Caq=QA**2./qa##          centripetal acceleration of A relative to Q in cm/s**2\n",

-      "Cap=Pa**2./pa##           centripetal acceleration of A relative to P in cm/s**2\n",

-      "pp1=530.\n",

-      "a1a=323.\n",

-      "a2a=207.5\n",

-      "ACP=pp1/cp##        angular acceleration of link CP in rad/s**2\n",

-      "APA=a1a/qa##        angular acceleration of link PA in rad/s**2\n",

-      "AAQ=a2a/pa##        angular acceleration of link AQ in rad/s**2\n",

-      "print'%s %.3f %s  %.3f %s  %.3f %s'%('angular acceleration of link CP =',ACP,' rad/s**2'' angular acceleration of link CP=',APA,' rad/s**2''angular acceleration of link CP=',AAQ,' rad/s**2')\n",

-      "\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "angular acceleration of link CP = 26.500  rad/s**2 angular acceleration of link CP=  32.300  rad/s**2angular acceleration of link CP=  41.500  rad/s**2\n"

-       ]

-      }

-     ],

-     "prompt_number": 4

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Theory_Of_Machines/Chapter5.ipynb b/_Theory_Of_Machines/Chapter5.ipynb
deleted file mode 100755
index f5d72d04..00000000
--- a/_Theory_Of_Machines/Chapter5.ipynb
+++ /dev/null
@@ -1,413 +0,0 @@
-{

- "metadata": {

-  "name": "",

-  "signature": "sha256:a109b0284cb0a4fc44bb60197ec78d6f24860fb5b5091b8f3432975ce1e08de6"

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Chapter5-Inertia Force Analysis in Machines"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Ex1-pg160"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 5 ILLUSRTATION 1 PAGE NO 160\n",

-      "##TITLE:Inertia Force Analysis in Machines\n",

-      "import math\n",

-      "pi=3.141\n",

-      "r=.3##          radius of crank in m\n",

-      "l=1.##           length of connecting rod in m\n",

-      "N=200.##         speed of the engine in rpm\n",

-      "n=l/r\n",

-      "##===================\n",

-      "w=2.*pi*N/60.##             angular speed in rad/s\n",

-      "\n",

-      "teeta=math.acos((-n+((n**2)+4*2*1)**.5)/(2*2))*57.3##         angle of inclination of crank in degrees\n",

-      "Vp=w*r*(math.sin(teeta/57.3)+(math.sin((2*teeta)/57.3)/n))##           maximum velocity of the piston in m/s\n",

-      "print'%s %.1f %s'%('Maximum velocity of the piston = ',Vp,' m/s')\n",

-      "print'%s %.2f %s'%('teeta',teeta,'')"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Maximum velocity of the piston =  7.0  m/s\n",

-        "teeta 74.96 \n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex2-pg161"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 5 ILLUSRTATION 2 PAGE NO 161\n",

-      "##TITLE:Inertia Force Analysis in Machines\n",

-      "import math\n",

-      "PI=3.141\n",

-      "r=.3##                 length of crank in metres\n",

-      "l=1.5##                length of connecting rod in metres\n",

-      "N=180.##                speed of rotation in rpm\n",

-      "teeta=40.##             angle of inclination of crank in degrees\n",

-      "##============================\n",

-      "n=l/r\n",

-      "w=2.*PI*N/60##        angular speed in rad/s\n",

-      "Vp=w*r*(math.sin(teeta/57.3)+math.sin((2.*teeta/57.3)/(2.*n)))##               velocity of piston in m/s\n",

-      "fp=w**2.*r*(math.cos(teeta/57.3)+math.cos(2.*teeta/57.3)/(2.*n))##            acceleration of piston in m/s**2\n",

-      "costeeta1=(-n+(n**2.+4.*2.*1.)**.5)/4.\n",

-      "teeta1=math.acos(costeeta1)*(57.3)##  position of crank from inner dead centre position for zero acceleration of piston\n",

-      "##===========================\n",

-      "print'%s %.1f %s %.1f %s %.1f %s'%('Velocity of Piston = ',Vp,' m/s'' Acceleration of piston =',fp,' m/s**2'' position of crank from inner dead centre position for zero acceleration of piston=',teeta1,' degrees')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Velocity of Piston =  4.4  m/s Acceleration of piston = 83.5  m/s**2 position of crank from inner dead centre position for zero acceleration of piston= 79.3  degrees\n"

-       ]

-      }

-     ],

-     "prompt_number": 2

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex3-pg161"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 5 ILLUSRTATION 3 PAGE NO 161\n",

-      "##TITLE:Inertia Force Analysis in Machines\n",

-      "import math\n",

-      "pi=3.141\n",

-      "D=.3##          Diameter of steam engine in m\n",

-      "L=.5##          length of stroke in m\n",

-      "r=L/2.\n",

-      "mR=100.##        equivalent of mass of reciprocating parts in kg\n",

-      "N=200.##         speed of engine in rpm\n",

-      "teeta=45##       angle of inclination of crank in degrees\n",

-      "p1=1.*10**6##        gas pressure in N/m**2\n",

-      "p2=35.*10**3##       back pressure in N/m**2\n",

-      "n=4.##              ratio of crank radius to the length of stroke\n",

-      "##=================================\n",

-      "w=2.*pi*N/60##           angular speed in rad/s\n",

-      "Fl=pi/4.*D**2.*(p1-p2)##     Net load on piston in N\n",

-      "Fi=mR*w**2*r*(math.cos(teeta/57.3)+math.cos((2*teeta)/57.3)/(2*n))##   inertia force due to reciprocating parts\n",

-      "Fp=Fl-Fi##              Piston effort\n",

-      "T=Fp*r*(math.sin(teeta/57.3)+(math.sin((2*teeta)/57.3))/(2.*(n**2-(math.sin(teeta/57.3))**2)**.5))\n",

-      "print'%s %.1f %s %.1f %s '%('Piston effort = ',Fp,' N' 'Turning moment on the crank shaft = ',T,' N-m')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Piston effort =  60447.0  NTurning moment on the crank shaft =  12604.2  N-m \n"

-       ]

-      }

-     ],

-     "prompt_number": 3

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex4-pg162"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 5 ILLUSRTATION 4 PAGE NO 162\n",

-      "##TITLE:Inertia Force Analysis in Machines\n",

-      "import math\n",

-      "pi=3.141\n",

-      "D=.10##            Diameter of petrol engine in m\n",

-      "L=.12##            Stroke length in m\n",

-      "l=.25##            length of connecting in m\n",

-      "r=L/2.\n",

-      "mR=1.2##          mass of piston in kg\n",

-      "N=1800.##           speed in rpm\n",

-      "teeta=25.##             angle of inclination of crank in degrees\n",

-      "p=680.*10**3##       gas pressure in N/m**2\n",

-      "n=l/r\n",

-      "g=9.81##           acceleration due to gravity\n",

-      "##=======================================\n",

-      "w=2.*pi*N/60.##                    angular speed in rpm\n",

-      "Fl=pi/4.*D**2.*p##          force due to gas pressure in N\n",

-      "Fi=mR*w**2.*r*(math.cos(teeta/57.3)+math.cos((2*teeta)/57.3)/(n))##   inertia force due to reciprocating parts in N\n",

-      "Fp=Fl-Fi+mR*g##            net force on piston in N\n",

-      "Fq=n*Fp/((n**2-(math.sin(teeta/57.3))**2.)**.5)##      resultant load on gudgeon pin in N\n",

-      "Fn=Fp*math.sin(teeta/57.3)/((n**2-(math.sin(teeta/57.3))**2.)**.5)##   thrust on cylinder walls in N\n",

-      "fi=Fl+mR*g##         inertia force of the reciprocating parts before the gudgeon pin load is reversed in N\n",

-      "w1=(fi/mR/r/(math.cos(teeta/57.3)+math.cos((2*teeta)/57.3)/(n)))**.5\n",

-      "N1=60.*w1/(2.*pi)\n",

-      "print'%s %.1f %s %.1f %s %.1f %s %.1f %s '%('Net force on piston = ',Fp,' N'' Resultant load on gudgeon pin = ',Fq,' N'' Thrust on cylinder walls = ',Fn,' N'' speed at which other things remining same,the gudgeon pin load would be reversed in directionm= ',N1,' rpm')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Net force on piston =  2639.3  N Resultant load on gudgeon pin =  2652.9  N Thrust on cylinder walls =  269.1  N speed at which other things remining same,the gudgeon pin load would be reversed in directionm=  2528.4  rpm \n"

-       ]

-      }

-     ],

-     "prompt_number": 4

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex5-pg163"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 5 ILLUSRTATION 5 PAGE NO 163\n",

-      "##TITLE:Inertia Force Analysis in Machines\n",

-      "##Figure 5.3\n",

-      "import math\n",

-      "pi=3.141\n",

-      "N=1800.##         speed of the petrol engine in rpm\n",

-      "r=.06##          radius of crank in m\n",

-      "l=.240##         length of connecting rod in m\n",

-      "D=.1##           diameter of the piston in m\n",

-      "mR=1##          mass of piston in kg\n",

-      "p=.8*10**6##       gas pressure in N/m**2\n",

-      "x=.012##          distance moved by piston in m\n",

-      "##===============================================\n",

-      "w=2.*pi*N/60.##              angular velocity of the engine in rad/s\n",

-      "n=l/r\n",

-      "Fl=pi/4.*D**2.*p##          load on the piston in N\n",

-      "teeta=32.##               by mearument from the figure 5.3\n",

-      "Fi=mR*w**2.*r*(math.cos(teeta/57.3)+math.cos((2*teeta)/57.3)/n)##   inertia force due to reciprocating parts in N\n",

-      "Fp=Fl-Fi##            net load on the gudgeon pin in N\n",

-      "Fq=n*Fp/((n**2.-(math.sin(teeta/57.3))**2.)**.5)##      thrust in the connecting rod in N\n",

-      "Fn=Fp*math.sin(teeta/57.3)/((n**2-(math.sin(teeta/57.3))**2)**.5)##   reaction between the piston and cylinder in N\n",

-      "w1=(Fl/mR/r/(math.cos(teeta/57.3)+math.cos((2*teeta)/57.3)/(n)))**.5\n",

-      "N1=60.*w1/(2.*pi)##                            \n",

-      "print'%s %.1f %s %.1f %s %.1f %s %.1f %s'%('Net load on the gudgeon pin= ',Fp,' N''Thrust in the connecting rod= ',Fq,' N'' Reaction between the cylinder and piston= ',Fn,' N'' The engine speed at which the above values become zero= ',N1,' rpm')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Net load on the gudgeon pin=  4241.2  NThrust in the connecting rod=  4278.9  N Reaction between the cylinder and piston=  566.8  N The engine speed at which the above values become zero=  3158.0  rpm\n"

-       ]

-      }

-     ],

-     "prompt_number": 5

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex6-pg165"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 5 ILLUSRTATION 6 PAGE NO 165\n",

-      "##TITLE:Inertia Force Analysis in Machines\n",

-      "import math\n",

-      "pi=3.141\n",

-      "D=.25##             diameter of horizontal steam engine in m\n",

-      "N=180.##             speed of the engine in rpm\n",

-      "d=.05##             diameter of piston in m\n",

-      "P=36000.##            power of the engine in watts\n",

-      "n=3.##                ration of length of connecting rod to the crank radius\n",

-      "p1=5.8*10**5##         pressure on cover end side in N/m**2\n",

-      "p2=0.5*10**5##          pressure on crank end side in N/m**2\n",

-      "teeta=40.##            angle of inclination of crank in degrees\n",

-      "m=45.##                mass of flywheel in kg\n",

-      "k=.65##               radius of gyration in m\n",

-      "##==============================\n",

-      "Fl=(pi/4.*D**2.*p1)-(pi/4.*(D**2.-d**2.)*p2)##          load on the piston in N\n",

-      "ph=(math.sin(teeta/57.3)/n)\n",

-      "phi=math.asin(ph)*57.3##                      angle of inclination of the connecting rod to the line of stroke in degrees\n",

-      "r=1.6*D/2.\n",

-      "T=Fl*math.sin((teeta+phi)/57.3)/math.cos(phi/57.3)*r##              torque exerted on crank shaft in N-m\n",

-      "Fb=Fl*math.cos((teeta+phi)/57.3)/math.cos(phi/57.3)##              thrust on the crank shaft bearing in N\n",

-      "TR=P*60./(2.*pi*N)##                              steady resisting torque in N-m\n",

-      "Ts=T-TR##                                       surplus torque available in N-m\n",

-      "a=Ts/(m*k**2)##                                   acceleration of the flywheel in rad/s**2\n",

-      "print'%s %.1f %s %.1f %s  %.1f %s  '%('Torque exerted on the crank shaft= ',T,' N-m'' Thrust on the crank shaft bearing= ',Fb,'N''Acceleration of the flywheel= ',a,' rad/s**2')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Torque exerted on the crank shaft=  4233.8  N-m Thrust on the crank shaft bearing=  16321.0 NAcceleration of the flywheel=   122.2  rad/s**2  \n"

-       ]

-      }

-     ],

-     "prompt_number": 6

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex7-pg166"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 5 ILLUSRTATION 7 PAGE NO 166\n",

-      "##TITLE:Inertia Force Analysis in Machines\n",

-      "import math\n",

-      "pi=3.141\n",

-      "D=.25##              diameter of vertical cylinder of steam engine in m\n",

-      "L=.45##              stroke length in m\n",

-      "r=L/2.\n",

-      "n=4.\n",

-      "N=360.##               speed of the engine in rpm\n",

-      "teeta=45.##            angle of inclination of crank in degrees\n",

-      "p=1050000.##              net pressure in N/m**2\n",

-      "mR=180.##               mass of reciprocating parts in kg\n",

-      "g=9.81##               acceleration due to gravity\n",

-      "##========================\n",

-      "Fl=p*pi*D**2./4.##               force on piston due to steam pressure in N\n",

-      "w=2.*pi*N/60.##                 angular speed in rad/s\n",

-      "Fi=mR*w**2.*r*(math.cos(teeta/57.3)+math.cos((2*teeta)/57.3)/(n))##   inertia force due to reciprocating parts in N\n",

-      "Fp=Fl-Fi+mR*g##              piston effort in N\n",

-      "phi=math.asin((math.sin(teeta/57.3)/n))*57.3##     angle of inclination of the connecting rod to the line of stroke in degrees\n",

-      "T=Fp*math.sin((teeta+phi)/57.3)/math.cos(phi/57.3)*r##              torque exerted on crank shaft in N-m\n",

-      "print'%s %.1f %s'%('Effective turning moment on the crank shaft= ',T,' N-m')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Effective turning moment on the crank shaft=  2366.2  N-m\n"

-       ]

-      }

-     ],

-     "prompt_number": 7

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex8-pg166"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 5 ILLUSRTATION 8 PAGE NO 166\n",

-      "##TITLE:Inertia Force Analysis in Machines\n",

-      "##figure 5.4\n",

-      "import math\n",

-      "pi=3.141\n",

-      "D=.25##              diameter of vertical cylinder of diesel engine in m\n",

-      "L=.40##              stroke length in m\n",

-      "r=L/2.\n",

-      "n=4.\n",

-      "N=300.##               speed of the engine in rpm\n",

-      "teeta=60.##            angle of inclination of crank in degrees\n",

-      "mR=200.##               mass of reciprocating parts in kg\n",

-      "g=9.81##               acceleration due to gravity\n",

-      "l=.8##                 length of connecting rod in m\n",

-      "c=14.##             compression ratio=v1/v2\n",

-      "p1=.1*10**6.##           suction pressure in n/m**2\n",

-      "i=1.35##               index of the law of expansion and compression \n",

-      "##==============================================================\n",

-      "Vs=pi/4.*D**2.*L##            swept volume in m**3\n",

-      "w=2.*pi*N/60.##                 angular speed in rad/s\n",

-      "Vc=Vs/(c-1.)\n",

-      "V3=Vc+Vs/10.##            volume at the end of injection of fuel in m**3\n",

-      "p2=p1*c**i##              final pressure in N/m**2\n",

-      "p3=p2##                  from figure\n",

-      "x=r*((1.-math.cos(teeta/57.3)+(math.sin(teeta/57.3))**2/(2.*n)))##          the displacement of the piston when the crank makes an angle 60 degrees with T.D.C\n",

-      "Va=Vc+pi*D**2.*x/4.\n",

-      "pa=p3*(V3/Va)**i\n",

-      "p=pa-p1##          difference of pressues on 2 sides of piston in N/m**2\n",

-      "Fl=p*pi*D**2./4.##     net load on piston in N\n",

-      "Fi=mR*w**2.*r*(math.cos(teeta/57.3)+math.cos(2.*teeta/57.3)/(n))##       inertia force due to reciprocating parts in N\n",

-      "Fp=Fl-Fi+mR*g##              piston effort in N\n",

-      "phi=math.asin((math.sin(teeta/57.3)/n))*57.3##     angle of inclination of the connecting rod to the line of stroke in degrees\n",

-      "T=Fp*math.sin((teeta+phi)/57.3)/math.cos(phi/57.3)*r##              torque exerted on crank shaft in N-m\n",

-      "print'%s %.1f %s'%('Effective turning moment on the crank shaft= ',T,' N-m')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Effective turning moment on the crank shaft=  8850.3  N-m\n"

-       ]

-      }

-     ],

-     "prompt_number": 8

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Theory_Of_Machines/screenshots/Chapter1.png b/_Theory_Of_Machines/screenshots/Chapter1.png
deleted file mode 100755
index eef4ed79..00000000
--- a/_Theory_Of_Machines/screenshots/Chapter1.png
+++ /dev/null
diff --git a/_Theory_Of_Machines/screenshots/Chapter2.png b/_Theory_Of_Machines/screenshots/Chapter2.png
deleted file mode 100755
index 82e1d651..00000000
--- a/_Theory_Of_Machines/screenshots/Chapter2.png
+++ /dev/null
diff --git a/_Theory_Of_Machines/screenshots/Chapter3.png b/_Theory_Of_Machines/screenshots/Chapter3.png
deleted file mode 100755
index a9869d84..00000000
--- a/_Theory_Of_Machines/screenshots/Chapter3.png
+++ /dev/null
diff --git a/_Theory_Of_Machines_by__B._K._Sarkar/Chapter10.ipynb b/_Theory_Of_Machines_by__B._K._Sarkar/Chapter10.ipynb
deleted file mode 100755
index 5ae48acb..00000000
--- a/_Theory_Of_Machines_by__B._K._Sarkar/Chapter10.ipynb
+++ /dev/null
@@ -1,507 +0,0 @@
-{

- "metadata": {

-  "name": "",

-  "signature": "sha256:5f892b8e3ed0a74f24a745bdf0e14528cdf96fe8388a860fc7931df67549db87"

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter10-Brakes and Dynamometers"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex1-pg268"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 10 ILLUSRTATION 1 PAGE NO 268\n",

-      "##TITLE:Brakes and Dynamometers\n",

-      "import math\n",

-      "#calculate torque transmitted by the block brake\n",

-      "##===========================================================================================\n",

-      "##INPUT DATA\n",

-      "d=0.32;##Diameter of the drum in m\n",

-      "qq=90.;##Angle of contact in degree\n",

-      "P=820.;##Force applied in N\n",

-      "U=0.35;##Coefficient of friction\n",

-      "\n",

-      "\n",

-      "U1=((4.*U*math.sin(45/57.3))/((qq*(3.14/180.))+math.sin(90./57.3)));##Equivalent coefficient of friction\n",

-      "F=((P*0.66)/((0.3/U1)-0.06));##Force value in N taking moments\n",

-      "TB=(F*(d/2.));##Torque transmitted in N.m\n",

-      "\n",

-      "print'%s %.4f %s'%('Torque transmitted by the block brake is ',TB,' N.m')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Torque transmitted by the block brake is  120.4553  N.m\n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex2-pg269"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 10 ILLUSRTATION 2 PAGE NO 269\n",

-      "##TITLE:Brakes and Dynamometers\n",

-      "import math\n",

-      "#calculate The bicycle travels a distance and makes  turns before it comes to rest\n",

-      "##===========================================================================================\n",

-      "##INPUT DATA\n",

-      "m=120.;##Mass of rider in kg\n",

-      "v=16.2;##Speed of rider in km/hr\n",

-      "d=0.9;##Diameter of the wheel in m\n",

-      "P=120.;##Pressure applied on the brake in N\n",

-      "U=0.06;##Coefficient of friction\n",

-      "\n",

-      "F=(U*P);##Frictional force in N\n",

-      "KE=((m*(v*(5./18.))**2.)/2.);##Kinematic Energy in N.m\n",

-      "S=(KE/F);##Distance travelled by the bicycle before it comes to rest in m\n",

-      "N=(S/(d*3.14));##Required number of revolutions\n",

-      "\n",

-      "print'%s %.1f %s %.1f %s'%('The bicycle travels a distance of ',S,' m'and'',N,'turns before it comes to rest')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "The bicycle travels a distance of  168.8  59.7 turns before it comes to rest\n"

-       ]

-      }

-     ],

-     "prompt_number": 2

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex3-pg270"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 10 ILLUSRTATION 3 PAGE NO 270\n",

-      "##TITLE:Brakes and Dynamometers\n",

-      "import math\n",

-      "#evaluvate maximum torque absorbed\n",

-      "##===========================================================================================\n",

-      "##INPUT DATA\n",

-      "S=3500.;##Force on each arm in N\n",

-      "d=0.36;##Diamter of the wheel in m\n",

-      "U=0.4;##Coefficient of friction \n",

-      "qq=100.;##Contact angle in degree\n",

-      "\n",

-      "qqr=(qq*(3.14/180));##Contact angle in radians\n",

-      "UU=((4*U*math.sin(50/57.3))/(qqr+(math.sin(100./57.3))));##Equivalent coefficient of friction\n",

-      "F1=(S*0.45)/((0.2/UU)+((d/2.)-0.04));##Force on fulcrum in N\n",

-      "F2=(S*0.45)/((0.2/UU)-((d/2.)-0.04));##Force on fulcrum in N\n",

-      "TB=(F1+F2)*(d/2.);##Maximum torque absorbed in N.m\n",

-      "\n",

-      "print'%s %.2f %s'%('Maximum torque absorbed is ',TB,' N.m')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Maximum torque absorbed is  1412.67  N.m\n"

-       ]

-      }

-     ],

-     "prompt_number": 3

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex4-pg271"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 10 ILLUSRTATION 4 PAGE NO 271\n",

-      "##TITLE:Brakes and Dynamometers\n",

-      "import math\n",

-      "#calculate The maximum braking torque on the drum\n",

-      "##===========================================================================================\n",

-      "##INPUT DATA\n",

-      "a=0.5;##Length of lever in m\n",

-      "d=0.5;##Diameter of brake drum in m\n",

-      "q=(5/8.)*(2*3.14);##Angle made in radians\n",

-      "b=0.1;##Distance between pin and fulcrum in m\n",

-      "P=2000.;##Effort applied in N\n",

-      "U=0.25;##Coefficient of friction\n",

-      "\n",

-      "T=math.exp(U*q);##Ratios of tension\n",

-      "T2=((P*a)/b);##Tension in N\n",

-      "T1=(T*T2);##Tension in N\n",

-      "TB=((T1-T2)*(d/2.))/1000.;##Maximum braking torque in kNm\n",

-      "\n",

-      "print'%s %.2f %s'%('The maximum braking torque on the drum is',TB,' kNm')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "The maximum braking torque on the drum is 4.17  kNm\n"

-       ]

-      }

-     ],

-     "prompt_number": 4

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex5-pg271"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 10 ILLUSRTATION 5 PAGE NO 271\n",

-      "##TITLE:Brakes and Dynamometers\n",

-      "import math\n",

-      "#caculate the brake is self -locking and tension in the side \n",

-      "##===========================================================================================\n",

-      "##INPUT DATA\n",

-      "q=220.;##Angle of contact in degree\n",

-      "T=340.;##Torque in Nm\n",

-      "d=0.32;##Diameter of drum in m\n",

-      "U=0.3;##Coefficient of friction\n",

-      "\n",

-      "Td=(T/(d/2.));##Difference in tensions in N\n",

-      "Tr=math.exp(U*(q*(3.14/180.)));##Ratio of tensions\n",

-      "T2=(Td/(Tr-1.));##Tension in N\n",

-      "T1=(Tr*T2);##Tension in N\n",

-      "P=((T2*(d/2.))-(T1*0.04))/0.5;##Force applied in N\n",

-      "b=(T1/T2)*4.;##Value of b in cm when the brake is self-locking\n",

-      "\n",

-      "print'%s %.2f %s  %.2f %s  %.2f %s '%('The value of b is ',b,' cm' 'when the brake is self-locking ' 'Tensions in the sides are ',T1,' N and',T2,' N')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "The value of b is  12.65  cmwhen the brake is self-locking Tensions in the sides are   3107.70  N and  982.70  N \n"

-       ]

-      }

-     ],

-     "prompt_number": 5

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex6-pg272"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 10 ILLUSRTATION 6 PAGE NO 272\n",

-      "##TITLE:Brakes and Dynamometers\n",

-      "import math\n",

-      "#calculate torque required and thickness necessary to limit the tensile stress to 70 and secton of the lever taking stress to 60 mpa\n",

-      "##===========================================================================================\n",

-      "##INPUT DATA\n",

-      "d=0.5;##Drum diamter in m\n",

-      "U=0.3;##Coefficient of friction\n",

-      "q=250;##Angle of contact in degree\n",

-      "P=750;##Force in N\n",

-      "a=0.1;##Band width in m\n",

-      "b=0.8;##Distance in m\n",

-      "ft=(70*10**6);##Tensile stress in Pa\n",

-      "f=(60*10**6);##Stress in Pa\n",

-      "b1=0.1;##Distance in m\n",

-      "\n",

-      "T=math.exp(U*(q*(3.14/180.)));##Tensions ratio\n",

-      "T2=(P*b*10.)/(T+1.);##Tension in N\n",

-      "T1=(T*T2);##Tension in N\n",

-      "TB=(T1-T2)*(d/2.);##Torque in N.m\n",

-      "t=(max(T1,T2)/(ft*a))*1000.;##Thickness in mm\n",

-      "M=(P*b);##bending moment at fulcrum in Nm\n",

-      "X=(M/((1/6.)*f));##Value of th**2\n",

-      "##t varies from 10mm to 15 mm. Taking t=15mm,\n",

-      "h=math.sqrt(X/(0.015))*1000.;##Section of the lever in m\n",

-      "\n",

-      "print'%s %.1f %s %.1f %s %.1f %s'%('Torque required is ',TB,' N.m' 'Thickness necessary to limit the tensile stress to 70 MPa is ',t,' mm ''Section of the lever taking stress to 60 MPa is ',h,' mm')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Torque required is  861.7  N.mThickness necessary to limit the tensile stress to 70 MPa is  0.7  mm Section of the lever taking stress to 60 MPa is  63.2  mm\n"

-       ]

-      }

-     ],

-     "prompt_number": 6

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex7-pg273"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 10 ILLUSRTATION 7 PAGE NO 273\n",

-      "##TITLE:Brakes and Dynamometers\n",

-      "#calculate value of x and value of power/bd ratio \n",

-      "import math\n",

-      "##===========================================================================================\n",

-      "##INPUT DATA\n",

-      "P1=30.;##Power in kW\n",

-      "N=1250.;##Speed in r.p.m\n",

-      "P=60.;##Applied force in N\n",

-      "d=0.8;##Drum diameter in m\n",

-      "q=310.;##Contact angle in degree\n",

-      "a=0.03;##Length of a in m\n",

-      "b=0.12;##Length of b in m\n",

-      "U=0.2;##Coefficient of friction\n",

-      "B=10.;##Band width in cm\n",

-      "D=80.;##Diameter in cm\n",

-      "\n",

-      "T=(P1*60000.)/(2.*3.14*N);##Torque in N.m\n",

-      "Td=(T/(d/2.));##Tension difference in N\n",

-      "Tr=math.exp(U*(q*(3.14/180.)));##Tensions ratio\n",

-      "T2=(Td/(Tr-1.));##Tension in N\n",

-      "T1=(Tr*T2);##Tension in N\n",

-      "x=((T2*b)-(T1*a))/P;##Distance in m;\n",

-      "X=(P1/(B*D));##Ratio\n",

-      "\n",

-      "print'%s %.3f %s %.3f %s'%('Value of x is ',x,' m '' Value of (Power/bD) ratio is ',X,'')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Value of x is  0.155  m  Value of (Power/bD) ratio is  0.037 \n"

-       ]

-      }

-     ],

-     "prompt_number": 7

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex8-pg274"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 10 ILLUSRTATION 8 PAGE NO 274\n",

-      "##TITLE:Brakes and Dynamometers\n",

-      "import math\n",

-      "#calculate time required to bring the shaft to the rest from its running condition\n",

-      "##===========================================================================================\n",

-      "##INPUT DATA\n",

-      "m=80.;##Mass of flywheel in kg\n",

-      "k=0.5;##Radius of gyration in m\n",

-      "N=250;##Speed in r.p.m\n",

-      "d=0.32;##Diamter of the drum in m\n",

-      "b=0.05;##Distance of pin in m\n",

-      "q=260.;##Angle of contact in degree\n",

-      "U=0.23;##Coefficient of friction\n",

-      "P=20;##Force in N\n",

-      "a=0.35;##Distance at which force is applied in m\n",

-      "\n",

-      "Tr=math.exp(U*q*(3.14/180.));##Tensions ratio\n",

-      "T2=(P*a)/b;##Tension in N\n",

-      "T1=(Tr*T2);##Tension in N\n",

-      "TB=(T1-T2)*(d/2.);##Torque in N.m\n",

-      "KE=((1/2.)*(m*k**2)*((2.*3.14*N)/60.)**2);##Kinematic energy of the rotating drum in Nm\n",

-      "N1=(KE/(TB*2.*3.14));##Speed in rpm\n",

-      "aa=((2*3.14*N)/60.)**2/(4.*3.14*N1);##Angular acceleration in rad/s**2\n",

-      "t=((2.*3.14*N)/60.)/aa;##Time in seconds\n",

-      "\n",

-      "print'%s %.1f %s'%('Time required to bring the shaft to the rest from its running condition is ',t,' seconds')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Time required to bring the shaft to the rest from its running condition is  12.7  seconds\n"

-       ]

-      }

-     ],

-     "prompt_number": 8

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex9-pg275"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 10 ILLUSRTATION 9 PAGE NO 275\n",

-      "##TITLE:Brakes and Dynamometers\n",

-      "import math\n",

-      "#calculate Minimum force required  and Time taken to bring to rest \n",

-      "##===========================================================================================\n",

-      "##INPUT DATA\n",

-      "n=12.;##Number of blocks\n",

-      "q=15.;##Angle subtended in degree\n",

-      "P=185.;##Power in kW\n",

-      "N=300.;##Speed in r.p.m\n",

-      "U=0.25;##Coefficient of friction\n",

-      "d=1.25;##Diamter in m\n",

-      "b1=0.04;##Distance in m\n",

-      "b2=0.14;##Distance in m\n",

-      "a=1.;##Diatance in m\n",

-      "m=2400.;##Mass of rotor in kg\n",

-      "k=0.5;##Radius of gyration in m\n",

-      "\n",

-      "Td=(P*60000.)/(2.*3.14*N*(d/2.));##Tension difference in N\n",

-      "T=Td*(d/2.);##Torque in Nm\n",

-      "Tr=((1+(U*math.tan(7.5/57.3)))/(1.-(U*math.tan(7.5/57.3))))**n;##Tension ratio\n",

-      "To=(Td/(Tr-1.));##Tension in N\n",

-      "Tn=(Tr*To);##Tension in N\n",

-      "P=((To*b2)-(Tn*b1))/a;##Force in N\n",

-      "aa=(T/(m*k**2));##Angular acceleration in rad/s**2\n",

-      "t=((2*3.14*N)/60.)/aa;##Time in seconds\n",

-      "\n",

-      "print'%s %.1f %s %.1f %s'%('Minimum force required is ',P,' N' 'Time taken to bring to rest is ',t,' seconds')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Minimum force required is  406.1  NTime taken to bring to rest is  3.2  seconds\n"

-       ]

-      }

-     ],

-     "prompt_number": 9

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex10-pg275"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 10 ILLUSRTATION 10 PAGE NO 275\n",

-      "##TITLE:Brakes and Dynamometers\n",

-      "import math\n",

-      "#calculate Maximum braking torque and Angular retardation of the drum and Time taken by the system to come to rest \n",

-      "##===========================================================================================\n",

-      "##INPUT DATA\n",

-      "n=12.;## Number of blocks\n",

-      "q=16.;##Angle subtended in degrees\n",

-      "d=0.9;##Effective diameter in m\n",

-      "m=2000.;##Mass in kg\n",

-      "k=0.5;##Radius of gyration in m\n",

-      "b1=0.7;##Distance in m\n",

-      "b2=0.03;##Distance in m\n",

-      "a=0.1;##Distance in m\n",

-      "P=180.;##Force in N\n",

-      "N=360.;##Speed in r.p.m\n",

-      "U=0.25;##Coefficient of friction\n",

-      "\n",

-      "Tr=((1.+(U*math.tan(8/57.3)))/(1.-(U*math.tan(8/57.3))))**n;##Tensions ratio\n",

-      "T2=(P*b1)/(a-(b2*Tr));##Tension in N\n",

-      "T1=(Tr*T2);##Tension in N\n",

-      "TB=(T1-T2)*(d/2.);##Torque in N.m\n",

-      "aa=(TB/(m*k**2.));##Angular acceleration in rad/s**2\n",

-      "t=((2.*3.14*N)/60.)/aa;##Time in seconds\n",

-      "\n",

-      "print'%s %.2f %s %.2f %s %.2f %s '%('(i) Maximum braking torque is ',TB,'Nm ''(ii) Angular retardation of the drum is ',aa,' rad/s**2''(iii) Time taken by the system to come to rest is ',t,' s')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "(i) Maximum braking torque is  2481.63 Nm (ii) Angular retardation of the drum is  4.96  rad/s**2(iii) Time taken by the system to come to rest is  7.59  s \n"

-       ]

-      }

-     ],

-     "prompt_number": 10

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Theory_Of_Machines_by__B._K._Sarkar/Chapter11.ipynb b/_Theory_Of_Machines_by__B._K._Sarkar/Chapter11.ipynb
deleted file mode 100755
index ec8d5927..00000000
--- a/_Theory_Of_Machines_by__B._K._Sarkar/Chapter11.ipynb
+++ /dev/null
@@ -1,450 +0,0 @@
-{

- "metadata": {

-  "name": "",

-  "signature": "sha256:ebcd9b3d07a8d6768db168aed38e578ce5aca1ce1a2df85108f9e88506949f89"

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter11-VIBRATIONS"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex1-pg290"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 11 ILLUSRTATION 1 PAGE NO 290\n",

-      "##TITLE:VIBRATIONS\n",

-      "import math\n",

-      "#calculate frequency of longitudinal vibration and transversve vibaration\n",

-      "##===========================================================================================\n",

-      "##INPUT DATA\n",

-      "PI=3.147\n",

-      "D=.1##                           DIAMETER OF SHAFT IN m\n",

-      "L=1.10##                          LENGTH OF SHAFT IN m\n",

-      "W=450##                          WEIGHT ON THE OTHER END OF SHAFT IN NEWTONS\n",

-      "E=200*10**9##                     YOUNGS MODUKUS OF SHAFT MATERIAL IN Pascals\n",

-      "##   =========================================================================================\n",

-      "A=PI*D**2./4.##                    AREA OF SHAFT IN mm**2\n",

-      "I=PI*D**4./64.##                   MOMENT OF INERTIA \n",

-      "delta=W*L/(A*E)##               STATIC DEFLECTION IN LONGITUDINAL VIBRATION OF SHAFT IN m\n",

-      "Fn=0.4985/(delta)**.5##         FREQUENCY OF LONGITUDINAL VIBRATION IN Hz\n",

-      "delta1=W*L**3./(3.*E*I)##           STATIC DEFLECTION IN TRANSVERSE VIBRATION IN m\n",

-      "Fn1=0.4985/(delta1)**.5##        FREQUENCY OF TRANSVERSE VIBRATION  IN Hz\n",

-      "##============================================================================================\n",

-      "##OUTPUT\n",

-      "print'%s %.2f %s %.2f %s '%('FREQUENCY OF LONGITUDINAL VIBRATION =',Fn,' Hz' 'FREQUENCY OF TRANSVERSE VIBRATION =',Fn1,'Hz')\n",

-      "\n",

-      "\n",

-      "\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "FREQUENCY OF LONGITUDINAL VIBRATION = 888.78  HzFREQUENCY OF TRANSVERSE VIBRATION = 34.99 Hz \n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex2-pg290"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 11 ILLUSRTATION 2 PAGE NO 290\n",

-      "##TITLE:VIBRATIONS\n",

-      "##FIGURE 11.10\n",

-      "#calculate natural frequency of transverse vibration\n",

-      "#import math\n",

-      "##===========================================================================================\n",

-      "##INPUT DATA\n",

-      "PI=3.147\n",

-      "L=.9##                          LENGTH OF THE SHAFT IN m\n",

-      "m=100##                         MASS OF THE BODY IN Kg\n",

-      "L2=.3##                         LENGTH WHERE THE WEIGHT IS ACTING IN m\n",

-      "L1=L-L2##                       DISTANCE FROM THE OTHER END\n",

-      "D=.06##                         DIAMETER OF SHAFT IN m\n",

-      "W=9.81*m##                      WEGHT IN NEWTON\n",

-      "E=200.*10**9.##                     YOUNGS MODUKUS OF SHAFT MATERIAL IN Pascals\n",

-      "##==========================================================================================\n",

-      "##CALCULATION\n",

-      "I=PI*D**4./64.##                   MOMENT OF INERTIA IN m**4\n",

-      "delta=W*L1**2*L2**2./(3.*E*I*L)##  STATIC DEFLECTION\n",

-      "Fn=.4985/(delta)**.5##           NATURAL FREQUENCY OF TRANSVERSE VIBRATION\n",

-      "##=========================================================================================\n",

-      "##OUTPUT\n",

-      "print'%s %.1f %s'%('NATURAL FREQUENCY OF TRANSVERSE VIBRATION=',Fn,' Hz')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "NATURAL FREQUENCY OF TRANSVERSE VIBRATION= 51.9  Hz\n"

-       ]

-      }

-     ],

-     "prompt_number": 2

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex3-pg291"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 11 ILLUSRTATION 3 PAGE NO 291 ##TITLE:VIBRATIONS\n",

-      "##FIGURE 11.11\n",

-      "import math\n",

-      "#calculate frequency of longitudnial vibration and frequency of transverse vibration and torisional vibration\n",

-      "##===========================================================================================\n",

-      "##INPUT DATA\n",

-      "PI=3.147\n",

-      "g=9.81##                                      ACCELERATION DUE TO GRAVITY IN N /m**2\n",

-      "D=.050##                                       DIAMETER OF SHAFT IN m\n",

-      "m=450##                                      WEIGHT OF FLY WHEEL IN IN Kg\n",

-      "K=.5##                                       RADIUS OF GYRATION IN m\n",

-      "L2=.6##                                     FROM FIGURE IN m\n",

-      "L1=.9##                                     FROM FIGURE IN m\n",

-      "L=L1+L2\n",

-      "E=200.*10**9##                     YOUNGS MODUKUS OF SHAFT MATERIAL IN Pascals\n",

-      "C=84.*10**9##                      MODUKUS OF RIDITY OF SHAFT MATERIAL IN Pascals\n",

-      "##=========================================================================================\n",

-      "A=PI*D**2./4.##                               AREA OF SHAFT IN mm**2\n",

-      "I=PI*D**4./64.##                     \n",

-      "m1=m*L2/(L1+L2)##                           MASS OF THE FLYWHEEL CARRIED BY THE LENGTH L1 IN Kg\n",

-      "DELTA=m1*g*L1/(A*E)##                       EXTENSION OF LENGTH L1 IN m\n",

-      "Fn=0.4985/(DELTA)**.5##                      FREQUENCY OF LONGITUDINAL VIBRATION IN Hz\n",

-      "DELTA1=(m*g*L1**3*L2**3)/(3*E*I*L**3)##        STATIC DEFLECTION IN TRANSVERSE VIBRATION IN m\n",

-      "Fn1=0.4985/(DELTA1)**.5##                    FREQUENCY OF TRANSVERSE VIBRATION  IN Hz\n",

-      "J=PI*D**4./32.##                               POLAR MOMENT OF INERTIA IN m**4\n",

-      "Q1=C*J/L1##                                 TORSIONAL STIFFNESS OF SHAFT DUE TO L1 IN N-m\n",

-      "Q2=C*J/L2##                                  TORSIONAL STIFFNESS OF SHAFT DUE TO L2 IN N-m\n",

-      "Q=Q1+Q2##                                    TORSIONAL STIFFNESS OF SHAFT IN Nm\n",

-      "Fn2=(Q/(m*K**2))**.5/(2.*PI)##                  FREQUENCY OF TORSIONAL VIBRATION  IN Hz\n",

-      "##=======================================================================================\n",

-      "print'%s %.3f %s %.3f %s %.3f %s '%('FREQUENCY OF LONGITUDINAL VIBRATION = ',Fn,' Hz''FREQUENCY OF TRANSVERSE VIBRATION = ',Fn1,' Hz'' FREQUENCY OF TORSIONAL VIBRATION = ',Fn2,' Hz')\n",

-      "\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "FREQUENCY OF LONGITUDINAL VIBRATION =  248.014  HzFREQUENCY OF TRANSVERSE VIBRATION =  14.916  Hz FREQUENCY OF TORSIONAL VIBRATION =  5.673  Hz \n"

-       ]

-      }

-     ],

-     "prompt_number": 3

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex6-pg294"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 11 ILLUSRTATION 6 PAGE NO 294\n",

-      "##TITLE:VIBRATIONS\n",

-      "##FIGURE 11.14\n",

-      "import math\n",

-      "#calculate frequency of transverse vibration\n",

-      "##===========================================================================================\n",

-      "##INPUT DATA\n",

-      "PI=3.147\n",

-      "g=9.81##                                      ACCELERATION DUE TO GRAVITY IN N /m**2\n",

-      "D=.06##                                       DIAMETER OF SHAFT IN m\n",

-      "L=3.##                                         LENGTH OF SHAFT IN m\n",

-      "W1=1500.##                                     WEIGHT ACTING AT C IN N\n",

-      "W2=2000.##                                     WEIGHT ACTING AT D IN N\n",

-      "W3=1000.##                                     WEIGHT ACTING AT E IN N\n",

-      "L1=1.##                                        LENGTH FROM A TO C IN m\n",

-      "L2=2.##                                        LENGTH FROM A TO D IN m\n",

-      "L3=2.5##                                        LENGTH FROM A TO E IN m\n",

-      "I=PI*D**4./64.\n",

-      "E=200.*10**9.##                     YOUNGS MODUKUS OF SHAFT MATERIAL IN Pascals\n",

-      "##===========================================================================================\n",

-      "DELTA1=W1*L1**2.*(L-L1)**2./(3.*E*I*L)##           STATIC DEFLECTION DUE TO W1\n",

-      "DELTA2=W2*L2**2.*(L-L2)**2./(3.*E*I*L)##           STATIC DEFLECTION DUE TO W2\n",

-      "DELTA3=W2*L3**2.*(L-L3)**2./(3.*E*I*L)##           STATIC DEFLECTION DUE TO W2\n",

-      "Fn=.4985/(DELTA1+DELTA2+DELTA3)**.5##          FREQUENCY OF TRANSVERSE VIBRATION  IN Hz\n",

-      "##==========================================================================================\n",

-      "print'%s %.3f %s'%('FREQUENCY OF TRANSVERSE VIBRATION = ',Fn,' Hz')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "FREQUENCY OF TRANSVERSE VIBRATION =  4.080  Hz\n"

-       ]

-      }

-     ],

-     "prompt_number": 4

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex10-pg296"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 11 ILLUSRTATION 10 PAGE NO 296\n",

-      "##TITLE:VIBRATIONS\n",

-      "##FIGURE 11.18\n",

-      "import math\n",

-      "#calculate FREQUENCY OF TRANSVERSE VIBRATION\n",

-      "##===========================================================================================\n",

-      "##INPUT DATA\n",

-      "PI=3.147\n",

-      "g=9.81##                                      ACCELERATION DUE TO GRAVITY IN N /m**2\n",

-      "E=200.*10**9##                                  YOUNGS MODUKUS OF SHAFT MATERIAL IN Pascals\n",

-      "D=.03##                                       DIAMETER OF SHAFT IN m\n",

-      "L=.8##                                        LENGTH OF SHAFT IN m\n",

-      "r=40000.##                                     DENSITY OF SHAFT MATERIAL IN Kg/m**3\n",

-      "W=10.##                                        WEIGHT ACTING AT CENTRE IN N\n",

-      "##===========================================================================================\n",

-      "I=PI*D**4./64.##                                 MOMENT OF INERTIA OF SHAFT IN m**4\n",

-      "m=PI*D**2./4.*r##                                MASS PER UNIT LENGTH IN Kg/m\n",

-      "w=m*g\n",

-      "DELTA=W*L**3./(48.*E*I)##                       STATIC DEFLECTION DUE TO W\n",

-      "DELTA1=5.*w*L**4./(384.*E*I)##                   STATIC DEFLECTION DUE TO WEIGHT OF SHAFT \n",

-      "Fn=.4985/(DELTA+DELTA1/1.27)**.5\n",

-      "##==========================================================================================\n",

-      "print'%s %.3f %s'%('FREQUENCY OF TRANSVERSE VIBRATION = ',Fn,' Hz')\n",

-      "\n",

-      "\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "FREQUENCY OF TRANSVERSE VIBRATION =  39.426  Hz\n"

-       ]

-      }

-     ],

-     "prompt_number": 5

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex11-pg297"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 11 ILLUSRTATION 11 PAGE NO 297\n",

-      "##TITLE:VIBRATIONS\n",

-      "##FIGURE 11.19\n",

-      "import math\n",

-      "#evaluvate CRITICAL SPEED OF SHAFT\n",

-      "##===========================================================================================\n",

-      "##INPUT DATA\n",

-      "PI=3.147\n",

-      "g=9.81##                                      ACCELERATION DUE TO GRAVITY IN N /m**2\n",

-      "E=210.*10**9.##                                  YOUNGS MODUKUS OF SHAFT MATERIAL IN Pascals\n",

-      "D=.18##                                       DIAMETER OF SHAFT IN m\n",

-      "L=2.5##                                       LENGTH OF SHAFT IN m\n",

-      "M1=25.##                                       MASS ACTING AT E IN Kg\n",

-      "M2=50.##                                       MASS ACTING AT D IN Kg\n",

-      "M3=20.##                                       MASS ACTING AT C IN Kg\n",

-      "W1=M1*g\n",

-      "W2=M2*g\n",

-      "W3=M3*g\n",

-      "L1=.6##                                       LENGTH FROM A TO E IN m\n",

-      "L2=1.5##                                      LENGTH FROM A TO D IN m\n",

-      "L3=2.##                                        LENGTH FROM A TO C IN m\n",

-      "w=1962.##                                      SELF WEIGHT OF SHAFT IN N\n",

-      "##==========================================================================================\n",

-      "I=PI*D**4./64.##                                 MOMENT OF INERTIA OF SHAFT IN m**4\n",

-      "DELTA1=W1*L1**2.*(L-L1)**2./(3.*E*I*L)##           STATIC DEFLECTION DUE TO W1\n",

-      "DELTA2=W2*L2**2.*(L-L2)**2./(3.*E*I*L)##           STATIC DEFLECTION DUE TO W2\n",

-      "DELTA3=W3*L3**2.*(L-L3)**2./(3.*E*I*L)##           STATIC DEFLECTION DUE TO W3\n",

-      "DELTA4=5.*w*L**4./(384.*E*I)##                    STATIC DEFLECTION DUE TO w\n",

-      "Fn=.4985/(DELTA1+DELTA2+DELTA3+DELTA4/1.27)**.5\n",

-      "Nc=Fn*60##                                   CRITICAL SPEED OF SHAFT IN rpm\n",

-      "##========================================================================================\n",

-      "print'%s %.3f %s'%('CRITICAL SPEED OF SHAFT = ',Nc,' rpm')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "CRITICAL SPEED OF SHAFT =  3111.629  rpm\n"

-       ]

-      }

-     ],

-     "prompt_number": 6

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex12-pg298"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 11 ILLUSRTATION 12 PAGE NO 298\n",

-      "##TITLE:VIBRATIONS\n",

-      "##FIGURE 11.20\n",

-      "import math\n",

-      "#calculate  FREQUENCY OF FREE TORSIONAL VIBRATION\n",

-      "##===========================================================================================\n",

-      "##INPUT DATA\n",

-      "PI=3.147\n",

-      "g=9.81##                                      ACCELERATION DUE TO GRAVITY IN N /m**2\n",

-      "Na=1500.##                                     SPEED OF SHAFT A IN rpm\n",

-      "Nb=500.##                                      SPEED OF SHAFT B IN rpm\n",

-      "G=Na/Nb##                                     GERA RATIO\n",

-      "L1=.18##                                       LENGTH OF SHAFT 1 IN m\n",

-      "L2=.45##                                       LENGTH OF SHAFT 2 IN m\n",

-      "D1=.045##                                      DIAMETER OF SHAFT 1 IN m\n",

-      "D2=.09##                                       DIAMETER OF SHAFT 2 IN m\n",

-      "C=84.*10**9##                      MODUKUS OF RIDITY OF SHAFT MATERIAL IN Pascals\n",

-      "Ib=1400.##                        MOMENT OF INERTIA OF PUMP IN Kg-m**2\n",

-      "Ia=400.##                         MOMENT OF INERTIA OF MOTOR IN Kg-m**2\n",

-      "\n",

-      "##======================================================================================\n",

-      "J=PI*D1**4./32.##                               POLAR MOMENT OF INERTIA IN m**4\n",

-      "Ib1=Ib/G**2.##                     MASS MOMENT OF INERTIA OF EQUIVALENT ROTOR IN m**2\n",

-      "L3=G**2.*L2*(D1/D2)**4.##            ADDITIONAL LENGTH OF THE EQUIVALENT SHAFT\n",

-      "L=L1+L3##                         TOTAL LENGTH OF EQUIVALENT SHAFT\n",

-      "La=L*Ib1/(Ia+Ib1)\n",

-      "Fn=(C*J/(La*Ia))**.5/(2.*PI)##      FREQUENCY OF FREE TORSIONAL VIBRATION IN Hz\n",

-      "##===================================================================================\n",

-      "print'%s %.2f %s'%('FREQUENCY OF FREE TORSIONAL VIBRATION = ',Fn,' Hz')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "FREQUENCY OF FREE TORSIONAL VIBRATION =  4.20  Hz\n"

-       ]

-      }

-     ],

-     "prompt_number": 7

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex13-pg300"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 11 ILLUSRTATION 13 PAGE NO 300\n",

-      "##TITLE:VIBRATIONS\n",

-      "##FIGURE 11.21\n",

-      "import math\n",

-      "#calculate critical speed of shaft and the range of speed \n",

-      "##===========================================================================================\n",

-      "##INPUT DATA\n",

-      "PI=3.147\n",

-      "g=9.81##                                      ACCELERATION DUE TO GRAVITY IN N /m**2\n",

-      "D=.015##                                        DIAMETER OF SHAFT IN m\n",

-      "L=1.00##                                         LENGTH OF SHAFT IN m\n",

-      "M=15.##                                           MASS OF SHAFT IN Kg\n",

-      "W=M*g\n",

-      "e=.0003##                                        ECCENTRICITY IN m\n",

-      "E=200.*10**9.##                                  YOUNGS MODUKUS OF SHAFT MATERIAL IN Pascals\n",

-      "f=70.*10**6.##                                        PERMISSIBLE STRESS IN N/m**2\n",

-      "##============================================================================================\n",

-      "I=PI*D**4./64.##                MOMENT OF INERTIA OF SHAFT IN m**4\n",

-      "DELTA=W*L**3./(192.*E*I)##      STATIC DEFLECTION IN m\n",

-      "Fn=.4985/(DELTA)**.5##           NATURAL FREQUENCY OF TRANSVERSE VIBRATION\n",

-      "Nc=Fn*60.##                   CRITICAL SPEED OF SHAFT IN rpm\n",

-      "M1=16.*f*I/(D*g*L)\n",

-      "W1=M1*g##                    ADDITIONAL LOAD ACTING\n",

-      "y=W1/W*DELTA##               ADDITIONAL DEFLECTION DUE TO W1\n",

-      "N1=Nc/(1.+e/y)**.5##              MIN SPEED IN rpm\n",

-      "N2=Nc/(1.-e/y)**.5##              MAX SPEED IN rpm\n",

-      "##===========================================================================================\n",

-      "print'%s %.3f %s %.3f %s %.3f %s '%('CRITICAL SPEED OF SHAFT = ',Nc,' rpm''THE RANGE OF SPEED IS FROM',N1,'rpm TO ',N2,' rpm')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "CRITICAL SPEED OF SHAFT =  762.330  rpmTHE RANGE OF SPEED IS FROM 709.555 rpm TO  828.955  rpm \n"

-       ]

-      }

-     ],

-     "prompt_number": 8

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Theory_Of_Machines_by__B._K._Sarkar/Chapter12.ipynb b/_Theory_Of_Machines_by__B._K._Sarkar/Chapter12.ipynb
deleted file mode 100755
index 6706c05c..00000000
--- a/_Theory_Of_Machines_by__B._K._Sarkar/Chapter12.ipynb
+++ /dev/null
@@ -1,380 +0,0 @@
-{

- "metadata": {

-  "name": "",

-  "signature": "sha256:2fbbfd8e1fae5de695230b7f28341e3abac22cade207682955694bcaba6d0716"

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter12-Balancing of reciprocating of masses"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex1-pg310"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 12 ILLUSRTATION 1 PAGE NO 310\n",

-      "##TITLE:Balancing of reciprocating of masses\n",

-      "import math\n",

-      "#calculate the magnitude of balance mass required and residual balance error\n",

-      "pi=3.141\n",

-      "N=250.##               speed of the reciprocating engine in rpm\n",

-      "s=18.##              length of stroke in mm\n",

-      "mR=120.##             mass of reciprocating parts in kg\n",

-      "m=70.##               mass of revolving parts in kg\n",

-      "r=.09##                radius of revolution of revolving parts in m\n",

-      "b=.15##               distance at which balancing mass located in m\n",

-      "c=2./3.##              portion of reciprocating mass balanced \n",

-      "teeta=30.##           crank angle from inner dead centre in degrees\n",

-      "##===============================\n",

-      "B=r*(m+c*mR)/b##             balance mass required in kg\n",

-      "w=2.*math.pi*N/60.##     angular speed in rad/s\n",

-      "F=mR*w**2.*r*(((1.-c)**2.*(math.cos(teeta/57.3))**2.)+(c**2.*(math.sin(teeta/57.3))**2.))**.5##      residual unbalanced forces in N\n",

-      "print'%s %.1f %s %.3f %s'%('Magnitude of balance mass required= ',B,'kg' and 'Residual unbalanced forces= ',F,' N')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Magnitude of balance mass required=  90.0 Residual unbalanced forces=  3263.971  N\n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex2-pg310"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 12 ILLUSRTATION 2 PAGE NO 310\n",

-      "##TITLE:Balancing of reciprocating of masses\n",

-      "#calculate speed and swaying couples \n",

-      "pi=3.141\n",

-      "g=10.##    acceleration due to gravity approximately in m/s**2\n",

-      "mR=240.##    mass of reciprocating parts per cylinder in kg\n",

-      "m=300.##     mass of rotating parts per cylinder in kg\n",

-      "a=1.8##distance between cylinder centres in m\n",

-      "c=.67##   portion of reciprocating mass to be balanced\n",

-      "b=.60##       radius of balance masses in m\n",

-      "r=24.##       crank radius in cm\n",

-      "R=.8##radius of thread of wheels in m\n",

-      "M=40.\n",

-      "##=======================================\n",

-      "Ma=m+c*mR##            total mass to be balanced in kg\n",

-      "mD=211.9##      mass of wheel D from figure in kg\n",

-      "mC=211.9##..... mass of wheel C from figure in kg\n",

-      "theta=171.##     angular position of balancing mass C in degrees\n",

-      "Br=c*mR/Ma*mC##       balancing mass for reciprocating parts in kg\n",

-      "w=(M*g**3./Br/b)**.5##   angular speed in rad/s\n",

-      "v=w*R*3600./1000.## speed in km/h\n",

-      "S=a*(1.-c)*mR*w**2*r/2.**.5/100./1000.##   swaying couple in kNm\n",

-      "print'%s %.3f %s %.3f %s'%('speed=',v,' kmph'and ' swaying couple=',S,' kNm')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "speed= 86.476  swaying couple= 21.812  kNm\n"

-       ]

-      }

-     ],

-     "prompt_number": 2

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex3-pg313"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 12 ILLUSRTATION 3 PAGE NO 313\n",

-      "##TITLE:Balancing of reciprocating of masses\n",

-      "#calculate hammer blow and tractive effort and swaying couple\n",

-      "import math\n",

-      "pi=3.141\n",

-      "g=10.##    acceleration due to gravity approximately in m/s**2\n",

-      "a=.70##distance between cylinder centres in m\n",

-      "r=60.## crank radius in cm\n",

-      "m=130.##mass of rotating parts per cylinder in kg\n",

-      "mR=210.## mass of reciprocating parts per cylinder in kg\n",

-      "c=.67## portion of reciprocating mass to be balanced\n",

-      "N=300.##e2engine speed in rpm\n",

-      "b=.64##       radius of balance masses in m\n",

-      "##============================\n",

-      "Ma=m+c*mR##            total mass to be balanced in kg\n",

-      "mA=100.44##         mass of wheel A from figure in kg\n",

-      "Br=c*mR/Ma*mA##       balancing mass for reciprocating parts in kg\n",

-      "H=Br*(2.*math.pi*N/60.)**2*b##   hammer blow in N\n",

-      "w=(2.*math.pi*N/60.)##    angular speed\n",

-      "T=2**.5*(1.-c)*mR*w**2.*r/2./100.##tractive effort in N\n",

-      "S=a*(1.-c)*mR*w**2.*r/2./2.**.5/100.##   swaying couple in Nm\n",

-      "\n",

-      "print'%s %.3f %s %.3f %s %.3f %s'%('Hammer blow=',H,' in N' 'tractive effort= ',T,' in N' 'swaying couple= ',S,' in Nm')\n",

-      "print '%s'%(\"The answer is a bit different due to rounding off error in textbook\")"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Hammer blow= 32975.566  in Ntractive effort=  29018.117  in Nswaying couple=  10156.341  in Nm\n",

-        "The answer is a bit different due to rounding off error in textbook\n"

-       ]

-      }

-     ],

-     "prompt_number": 3

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex4-pg314"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 12 ILLUSRTATION 4 PAGE NO 314\n",

-      "##TITLE:Balancing of reciprocating of masses\n",

-      "import math\n",

-      "#calculate maximum unbalanced primary couples\n",

-      "pi=3.141\n",

-      "mR=900.##   mass of reciprocating parts in kg\n",

-      "N=90.##     speed of the engine in rpm\n",

-      "r=.45##crank radius in m\n",

-      "cP=.9*mR*(2.*math.pi*N/60.)**2.*r*2.**.5/1000.##    maximum unbalanced primary couple in kNm\n",

-      "print'%s %.3f %s'%('maximum unbalanced primary couple=',cP,'  k Nm')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "maximum unbalanced primary couple= 45.788   k Nm\n"

-       ]

-      }

-     ],

-     "prompt_number": 4

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex5-pg315"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 12 ILLUSRTATION 5 PAGE NO 315\n",

-      "##TITLE:Balancing of reciprocating of masses\n",

-      "import math\n",

-      "#calculate maximum unbalanced secondary force and with reasons\n",

-      "pi=3.141\n",

-      "mRA=160.##   mass of reciprocating cylinder A in kg\n",

-      "mRD=160.##   mass of reciprocating cylinder D in kg\n",

-      "r=.05## stroke lenght in m\n",

-      "l=.2##  connecting rod length in m\n",

-      "N=450.##   engine speed in rpm\n",

-      "##===========================\n",

-      "theta2=78.69##           crank angle between A & B  cylinders in degrees\n",

-      "mRB=576.88##  mass of cylinder B in kg\n",

-      "n=l/r##    ratio between connecting rod length and stroke length\n",

-      "w=2.*math.pi*N/60.##   angular speed in rad/s\n",

-      "F=mRB*2.*w**2.*r*math.cos((2.*theta2)/57.3)/n\n",

-      "print'%s %.3f %s'%('Maximum unbalanced secondary force=',F,' N in anticlockwise direction thats why - sign')\n",

-      "print '%s'%(\"The answer is a bit different due to rounding off error in textbook\")"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Maximum unbalanced secondary force= -29560.284  N in anticlockwise direction thats why - sign\n",

-        "The answer is a bit different due to rounding off error in textbook\n"

-       ]

-      }

-     ],

-     "prompt_number": 5

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex6-pg316"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 12 ILLUSRTATION 6 PAGE NO 316\n",

-      "##TITLE:Balancing of reciprocating of masses\n",

-      "import math\n",

-      "pi=3.141\n",

-      "rA=.25##     stroke length of A piston  in m\n",

-      "rB=.25##    stroke length of B piston  in m\n",

-      "rC=.25## stroke length C piston  in m\n",

-      "N=300.## engine speed in rpm\n",

-      "mRL=280.## mass of reciprocating parts in inside cylinder kg\n",

-      "mRO=240.##   mass of reciprocating parts in outside cylinder kg\n",

-      "c=.5##  portion ofreciprocating masses to be balanced \n",

-      "b1=.5##  radius at which masses to be balanced in m\n",

-      "##======================\n",

-      "mA=c*mRO##    mass of the reciprocating parts to be balanced foreach outside cylinder in kg\n",

-      "mB=c*mRL##    mass of the reciprocating parts to be balanced foreach inside cylinder in kg\n",

-      "B1=79.4##         balancing mass for reciprocating parts in kg\n",

-      "w=2.*math.pi*N/60.##   angular speed in rad/s\n",

-      "H=B1*w**2*b1##   hammer blow per wheel in N\n",

-      "print'%s %.1f %s'%('Hammer blow per wheel= ',H,' N')\n",

-      "print '%s'%(\"The answer is a bit different due to rounding off error in textbook\")"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Hammer blow per wheel=  39182.3  N\n",

-        "The answer is a bit different due to rounding off error in textbook\n"

-       ]

-      }

-     ],

-     "prompt_number": 6

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex7-pg318"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 12 ILLUSRTATION 7 PAGE NO 318\n",

-      "##TITLE:Balancing of reciprocating of masses\n",

-      "import math\n",

-      "\n",

-      "pi=3.141\n",

-      "mR=300.##    reciprocating mass per cylinder in kg\n",

-      "r=.3##   crank radius in m\n",

-      "D=1.7##  driving wheel diameter in m\n",

-      "a=.7##  distance between cylinder centre lines in m\n",

-      "H=40.##  hammer blow in kN\n",

-      "v=90.##   speed in kmph\n",

-      "##=======================================\n",

-      "R=D/2.##     radius of driving wheel in m\n",

-      "w=90.*1000./3600./R##        angular velocity in rad/s\n",

-      "##Br*b=69.625*c  by mearument from diagram\n",

-      "c=H*1000./(w**2.)/69.625##   portion of reciprocating mass to be balanced\n",

-      "T=2.**.5*(1-c)*mR*w**2.*r##   variation in tractive effort in N\n",

-      "M=a*(1.-c)*mR*w**2.*r/2.**.5##     maximum swaying couple in N-m\n",

-      "print'%s %.3f %s %.3f %s %.3f %s'%('portion of reciprocating mass to be balanced=',c,' ''variation in tractive effort=',T,' N'' maximum swaying couple=',M,' N-m')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "portion of reciprocating mass to be balanced= 0.664  variation in tractive effort= 36980.420  N maximum swaying couple= 12943.147  N-m\n"

-       ]

-      }

-     ],

-     "prompt_number": 7

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex8-pg320"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 12 ILLUSRTATION 8 PAGE NO 320\n",

-      "##TITLE:Balancing of reciprocating of masses\n",

-      "import math\n",

-      "pi=3.141\n",

-      "N=1800.##       speed of the engine in rpm\n",

-      "r=6.##     length of crank in cm\n",

-      "l=24.##    length of connecting rod in cm\n",

-      "m=1.5##   mass of reciprocating cylinder in kg\n",

-      "##====================\n",

-      "w=2.*math.pi*N/60.##        angular speed in rad/s\n",

-      "UPC=.019*w**2.##      unbalanced primary couple in N-m\n",

-      "n=l/r##   ratio of length of crank to the connecting rod \n",

-      "USC=.054*w**2./n##    unbalanced secondary couple in N-m\n",

-      "print'%s %.f %s %.3f %s '%('unbalanced primary couple=',UPC,'N-m' 'unbalanced secondary couple=',USC,' N-m')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "unbalanced primary couple= 675 N-munbalanced secondary couple= 479.663  N-m \n"

-       ]

-      }

-     ],

-     "prompt_number": 8

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Theory_Of_Machines_by__B._K._Sarkar/Chapter2.ipynb b/_Theory_Of_Machines_by__B._K._Sarkar/Chapter2.ipynb
deleted file mode 100755
index 0ed80f3b..00000000
--- a/_Theory_Of_Machines_by__B._K._Sarkar/Chapter2.ipynb
+++ /dev/null
@@ -1,824 +0,0 @@
-{

- "metadata": {

-  "name": "",

-  "signature": "sha256:1b022ca97a90c946dcce72b014fa00f7dd7b26ac917f0b5fe9fdd6cabd6dcdfd"

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter2-TRANSMISSION OF MOTION AND POWER BY BELTS AND PULLEYS"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex1-pg57"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 2 ILLUSRTATION 1 PAGE NO 57\n",

-      "##TITLE:TRANSMISSION OF MOTION AND POWER BY BELTS AND PULLEYS\n",

-      "import math\n",

-      "##===========================================================================================\n",

-      "##INPUT DATA\n",

-      "Na=300.;##driving shaft running speed in rpm\n",

-      "Nb=400.;##driven shaft running speed in rpm\n",

-      "Da=60.;##diameter of driving shaft in mm\n",

-      "t=.8;##belt thickness in mm\n",

-      "s=.05;##slip in percentage(5%)\n",

-      "##==========================================================================================\n",

-      "##calculation\n",

-      "Db=(Da*Na)/Nb;##finding out the diameter of driven shaft without considering the thickness of belt\n",

-      "Db1=(((Da+t)*Na)/Nb)-t##/considering the thickness\n",

-      "Db2=(1.-s)*(Da+t)*(Na/Nb)-t##considering slip also\n",

-      "##=========================================================================================\n",

-      "##output\n",

-      "print'%s %.1f %s'%('the value of Db is',Db,' cm')\n",

-      "print'%s %.1f %s'%('the value of Db1 is',Db1,' cm')\n",

-      "print'%s %.1f %s'%('the value of Db2 is',Db2,' cm')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "the value of Db is 45.0  cm\n",

-        "the value of Db1 is 44.8  cm\n",

-        "the value of Db2 is 42.5  cm\n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex2-pg57"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 2,ILLUSRTATION 2 PAGE NO 57\n",

-      "##TITLE:TRANSMISSION OF MOTION AND POWER BY BELTS AND PULLEYS\n",

-      "\n",

-      "##====================================================================================\n",

-      "##input\n",

-      "n1=1200##rpm of motor shaft\n",

-      "d1=40##diameter of motor pulley in cm\n",

-      "d2=70##diameter of 1st pulley on the shaft in cm\n",

-      "s=.03##percentage slip(3%)\n",

-      "d3=45##diameter of 2nd pulley\n",

-      "d4=65##diameter of the pulley on the counnter shaft\n",

-      "##=========================================================================================\n",

-      "##calculation\n",

-      "n2=n1*d1*(1-s)/d2##rpm of driven shaft\n",

-      "n3=n2##both the pulleys are mounted on the same shaft\n",

-      "n4=n3*(1-s)*d3/d4##rpm of counter shaft\n",

-      "\n",

-      "##output\n",

-      "print'%s %.1f %s %.1f %s '%('the speed of driven shaft is',n2,' rpm''the speed of counter shaft is ',n4,' rpm')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "the speed of driven shaft is 665.1  rpmthe speed of counter shaft is  446.7  rpm \n"

-       ]

-      }

-     ],

-     "prompt_number": 2

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex3-pg58"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 2 ILLUSTRATION 3 PAGE NO:58\n",

-      "##TITLE:TRANSMISSION OF MOTION AND POWER BY BELTS AND PULLEYS\n",

-      "import math\n",

-      "##==============================================================================\n",

-      "##input\n",

-      "d1=30.##diameter of 1st shaft in cm\n",

-      "d2=50.##diameter 2nd shaft in cm\n",

-      "pi=3.141\n",

-      "c=500.##centre distance between the shafts in cm\n",

-      "##==============================================================================\n",

-      "##calculation\n",

-      "L1=((d1+d2)*pi/2.)+(2.*c)+((d1+d2)**2.)/(4.*c)##lenth of cross belt\n",

-      "L2=((d1+d2)*pi/2.)+(2.*c)+((d1-d2)**2.)/(4.*c)##lenth of open belt\n",

-      "r=L1-L2##remedy\n",

-      "##==============================================================================\n",

-      "##OUTPUT\n",

-      "print'%s %.1f %s %.1f %s %.1f %s '%('length of cross belt is ',L1,'cm '' length of open belt is ',L2,'cm''the length of the belt to be shortened is ',r,' cm')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "length of cross belt is  1128.8 cm  length of open belt is  1125.8 cmthe length of the belt to be shortened is  3.0  cm \n"

-       ]

-      }

-     ],

-     "prompt_number": 3

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex4-pg59"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "\n",

-      "##CHAPTER 2,ILLUSTRATION 4 PAGE 59\n",

-      "##TITLE:TRANSMISSION OF MOTION AND POWER BY BELTS AND PULLEYS\n",

-      "import math\n",

-      "##====================================================================================\n",

-      "##INPUT\n",

-      "D1=.5##            DIAMETER OF 1ST SHAFT IN m\n",

-      "D2=.25##           DIAMETER OF 2nd SHAFT IN m\n",

-      "C=2.##              CENTRE DISTANCE IN m\n",

-      "N1=220.##           SPEED OF 1st SHAFT\n",

-      "T1=1250.##          TENSION ON TIGHT SIDE IN N\n",

-      "U=.25##            COEFFICIENT OF FRICTION\n",

-      "PI=3.141\n",

-      "e=2.71\n",

-      "##====================================================================================\n",

-      "##CALCULATION\n",

-      "L=(D1+D2)*PI/2.+((D1+D2)**2./(4.*C))+2.*C\n",

-      "F=(D1+D2)/(2.*C)\n",

-      "ALPHA=math.asin(F/57.3)\n",

-      "THETA=(180.+(2.*ALPHA))*PI/180.##   ANGLE OF CONTACT IN radians\n",

-      "T2=T1/(e**(U*THETA))##            TENSION ON SLACK SIDE IN N\n",

-      "V=PI*D1*N1/60.##                   VELOCITY IN m/s\n",

-      "P=(T1-T2)*V/1000.##                POWER IN kW\n",

-      "##====================================================================================\n",

-      "##OUTPUT\n",

-      "print'%s %.1f %s'%('LENGTH OF BELT REQUIRED =',L,' m')\n",

-      "print'%s %.1f %s'%('ANGLE OF CONTACT =',THETA,' radians')\n",

-      "print'%s %.1f %s'%('POWER CAN BE TRANSMITTED=',P,' kW')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "LENGTH OF BELT REQUIRED = 5.2  m\n",

-        "ANGLE OF CONTACT = 3.1  radians\n",

-        "POWER CAN BE TRANSMITTED= 3.9  kW\n"

-       ]

-      }

-     ],

-     "prompt_number": 4

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex5-pg59"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 2,ILLUSTRATION 5 PAGE 5\n",

-      "##TITLE:TRANSMISSION OF MOTION AND POWER BY BELTS AND PULLEYS\n",

-      "import math\n",

-      "##=====================================================================================================\n",

-      "##input\n",

-      "n1=100.## of driving shaft\n",

-      "n2=240.##speed of driven shaft\n",

-      "p=11000.##power to be transmitted in watts\n",

-      "c=250.##centre distance in cm\n",

-      "d2=60.##diameter in cm\n",

-      "b=11.5*10**-2##width of belt in metres\n",

-      "t=1.2*10**-2##thickness in metres\n",

-      "u=.25##co-efficient of friction \n",

-      "pi=3.141\n",

-      "e=2.71\n",

-      "##===================================================================================================\n",

-      "##calculation for open bely drive\n",

-      "d1=n2*d2/n1\n",

-      "f=(d1-d2)/(2.*c)##sin(alpha) for open bely drive\n",

-      "##angle of arc of contact for open belt drive is,theta=180-2*alpha\n",

-      "alpha=math.asin(f)*57.3\n",

-      "teta=(180.-(2*alpha))*3.147/180.##pi/180 is used to convert into radians\n",

-      "x=(e**(u*teta))##finding out the value of t1/t2\n",

-      "v=pi*d2*10.*n2/60.##finding out the value of t1-t2\n",

-      "y=p*1000./(v)\n",

-      "t1=(y*x)/(x-1.)\n",

-      "Fb=t1/(t*b)/1000.\n",

-      "##=======================================================================================================\n",

-      "##calculation for cross belt drive bely drive\n",

-      "F=(d1+d2)/(2.*c)##for cross belt drive bely drive\n",

-      "ALPHA=math.asin(F)*57.3\n",

-      "THETA=(180.+(2.*ALPHA))*pi/180.##pi/180 is used to convert into radians\n",

-      "X=(e**(u*THETA))##finding out the value of t1/t2\n",

-      "V=pi*d2*10.*n2/60.##finding out the value of t1-t2\n",

-      "Y=p*1000./(V)\n",

-      "T1=(Y*X)/(X-1.)\n",

-      "Fb2=T1/(t*b)/1000.\n",

-      "##========================================================================================================\n",

-      "##output\n",

-      "print('for a open belt drive:')\n",

-      "print'%s %.1f %s %.1f %s'%('the tension in  belt is ',t1,'N'     'stress induced is ',Fb,' kN/m**2')\n",

-      "print('for a cross belt drive:')\n",

-      "print'%s %.1f %s %.1f %s '%('the tension in belt is ',T1,'N'     'stress induced is ',Fb2,' kN/m**2')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "for a open belt drive:\n",

-        "the tension in  belt is  2898.4 Nstress induced is  2100.3  kN/m**2\n",

-        "for a cross belt drive:\n",

-        "the tension in belt is  2318.8 Nstress induced is  1680.3  kN/m**2 \n"

-       ]

-      }

-     ],

-     "prompt_number": 5

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex6-pg61"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 2,ILLUSTRATION 6 PAGE 61\n",

-      "##TITLE:TRANSMISSION OF MOTION AND POWER BY BELTS AND PULLEYS\n",

-      "import math\n",

-      "##========================================================================================\n",

-      "##INPUT\n",

-      "D1=80.##DIAMETER OF SHAFT IN cm\n",

-      "N1=160.##SPEED OF 1ST SHAFT IN rpm\n",

-      "N2=320.##SPEED OF 2ND SHAFT IN rpm\n",

-      "C=250.##CENTRE DISTANCE IN CM\n",

-      "U=.3##COEFFICIENT OF FRICTION\n",

-      "P=4.##POWER IN KILO WATTS\n",

-      "e=2.71\n",

-      "PI=3.141\n",

-      "f=110.##STRESS PER cm WIDTH OF BELT\n",

-      "##========================================================================================\n",

-      "##CALCULATION\n",

-      "V=PI*D1*math.pow(10,-2)*N1/60.##VELOCITY IN m/s\n",

-      "Y=P*1000./V##Y=T1-T2\n",

-      "D2=D1*(N1/N2)##DIAMETER OF DRIVEN SHAFT\n",

-      "F=(D1-D2)/(2.*C)\n",

-      "ALPHA=math.asin(F/57.3)\n",

-      "THETA=(180.-(2.*ALPHA))*PI/180.##ANGLE OF CONTACT IN radians\n",

-      "X=e**(U*THETA)##VALUE OF T1/T2\n",

-      "T1=X*Y/(X-1.)\n",

-      "b=T1/f##WIDTH OF THE BELT REQUIRED \n",

-      "##=======================================================================================\n",

-      "##OUTPUT\n",

-      "print'%s %.1f %s'%('THE WIDTH OF THE BELT IS ',b,' cm')\n",

-      "#apporximate ans is correct "

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "THE WIDTH OF THE BELT IS  8.9  cm\n"

-       ]

-      }

-     ],

-     "prompt_number": 6

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex7-pg62"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 2 ILLUSRTATION 7 PAGE NO 62\n",

-      "##TITLE:TRANSMISSION OF MOTION AND POWER BY BELTS AND PULLEYS\n",

-      "\n",

-      "##===========================================================================================\n",

-      "##INPUT DATA\n",

-      "m=1000.##                             MASS OF THE CASTING IN kg\n",

-      "PI=3.141\n",

-      "THETA=2.75*2*PI##                    ANGLE OF CONTACT IN radians\n",

-      "D=.26##                               DIAMETER OF DRUM IN m\n",

-      "N=24.##                                SPEED OF THE DRUM IN rpm\n",

-      "U=.25##                               COEFFICIENT OF FRICTION\n",

-      "e=2.71\n",

-      "T1=9810##                             TENSION ON TIGHTSIDE IN N\n",

-      "##=============================================================================================\n",

-      "##CALCULATION\n",

-      "T2=T1/(e**(U*THETA))##                 tension on slack side of belt in N\n",

-      "W=m*9.81##                            WEIGHT OF CASTING IN N\n",

-      "R=D/2.##                               RADIUS OF DRUM IN m\n",

-      "P=2*PI*N*W*R/60000.##                  POWER REQUIRED IN kW\n",

-      "P2=(T1-T2)*PI*D*N/60000.##                  POWER SUPPLIED BY DRUM IN kW\n",

-      "##============================================================================================\n",

-      "##OUTPUT\n",

-      "print'%s %.1f %s %.1f %s %.1f %s '%('FORCE REQUIRED BY MAN=',T2,' N'and 'POWER REQUIRED TO RAISE CASTING=',P,' kW' 'POWER SUPPLIED BY DRUM=',P2,' kW')\n",

-      "\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "FORCE REQUIRED BY MAN= 132.4 POWER REQUIRED TO RAISE CASTING= 3.2  kWPOWER SUPPLIED BY DRUM= 3.2  kW \n"

-       ]

-      }

-     ],

-     "prompt_number": 7

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex8-pg62"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 2,ILLUSTRATION 8 PAGE 62\n",

-      "##TITLE:TRANSMISSION OF MOTION AND POWER BY BELTS AND PULLEYS\n",

-      "import math\n",

-      "##INPUT\n",

-      "t=9.##THICKNESS IN mm\n",

-      "b=250.##WIDTH IN mm\n",

-      "D=90.##DIAMETER OF PULLEY IN cm\n",

-      "N=336.##SPEED IN rpm\n",

-      "PI=3.141\n",

-      "U=.35##COEFFICIENT FRICTION\n",

-      "e=2.71\n",

-      "THETA=120.*PI/180.\n",

-      "Fb=2.##STRESS IN MPa\n",

-      "d=1000.##DENSITY IN KG/M**3\n",

-      "\n",

-      "##CALCULATION\n",

-      "M=b*10**-3.*t*10**-3.*d##MASS IN KG\n",

-      "V=PI*D*10**-2.*N/60.##VELOCITY IN m/s\n",

-      "Tc=M*V**2##CENTRIFUGAL TENSION\n",

-      "Tmax=b*t*Fb##MAX TENSION IN N\n",

-      "T1=Tmax-Tc\n",

-      "T2=T1/(e**(U*THETA))\n",

-      "P=(T1-T2)*V/1000.\n",

-      "\n",

-      "##OUTPUT\n",

-      "print'%s %.1f %s'%('THE TENSION ON TIGHT SIDE OF THE BELT IS',T1,' N')\n",

-      "print'%s %.1f %s'%('THE TENSION ON SLACK SIDE OF THE BELT IS ',T2,' N')\n",

-      "print'%s %.1f %s'%('CENTRIFUGAL TENSION =',Tc,'N')\n",

-      "print'%s %.1f %s'%('THE POWER CAPACITY OF BELT IS ',P,' KW')\n",

-      "\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "THE TENSION ON TIGHT SIDE OF THE BELT IS 3936.1  N\n",

-        "THE TENSION ON SLACK SIDE OF THE BELT IS  1895.6  N\n",

-        "CENTRIFUGAL TENSION = 563.9 N\n",

-        "THE POWER CAPACITY OF BELT IS  32.3  KW\n"

-       ]

-      }

-     ],

-     "prompt_number": 9

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex9-pg63"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 2,ILLUSTRATION 9 PAGE 63\n",

-      "##TITLE:TRANSMISSION OF MOTION AND POWER BY BELTS AND PULLEYS\n",

-      "import math\n",

-      "##INPUT\n",

-      "P=35000.##POWER TO BE TRANSMITTED IN WATTS\n",

-      "D=1.5##EFFECTIVE DIAMETER OF PULLEY IN METRES\n",

-      "N=300.##SPEED IN rpm\n",

-      "e=2.71\n",

-      "U=.3##COEFFICIENT OF FRICTION\n",

-      "PI=3.141\n",

-      "THETA=(11/24.)*360.*PI/180.##ANGLE OF CONTACT\n",

-      "density=1.1##density of belt material in Mg/m**3\n",

-      "L=1.##in metre\n",

-      "t=9.5##THICKNESS OF BELT IN mm\n",

-      "Fb=2.5##PERMISSIBLE WORK STRESS IN N/mm**2\n",

-      "\n",

-      "##CALCULATION\n",

-      "V=PI*D*N/60.##VELOCITY IN m/s\n",

-      "X=P/V##X=T1-T2\n",

-      "Y=e**(U*THETA)##Y=T1/T2\n",

-      "T1=X*Y/(Y-1)\n",

-      "Mb=t*density*L/10**3.##value of m/b\n",

-      "Tc=Mb*V**2.##centrifugal tension/b\n",

-      "Tmaxb=t*Fb##max tension/b\n",

-      "b=T1/(Tmaxb-Tc)##thickness in mm\n",

-      "##output\n",

-      "print'%s %.1f %s'%('TENSION IN TIGHT SIDE OF THE BELT =',T1,' N')\n",

-      "print'%s %.1f %s'%('THICKNESS OF THE BELT IS =',b,' mm')\n",

-      "\n",

-      "\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "TENSION IN TIGHT SIDE OF THE BELT = 2573.5  N\n",

-        "THICKNESS OF THE BELT IS = 143.4  mm\n"

-       ]

-      }

-     ],

-     "prompt_number": 10

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex10-pg64"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 2,ILLUSTRATION 10 PAGE 64\n",

-      "##TITLE:TRANSMISSION OF MOTION AND POWER BY BELTS AND PULLEYS\n",

-      "import math\n",

-      "##INPUT\n",

-      "t=5.##THICKNESS OF BELT IN m\n",

-      "PI=3.141\n",

-      "U=.3\n",

-      "e=2.71\n",

-      "THETA=155.*PI/180.##ANGLE OF CONTACT IN radians\n",

-      "V=30.##VELOCITY IN m/s\n",

-      "density=1.##in m/cm**3\n",

-      "L=1.##LENGTH\n",

-      "\n",

-      "##calculation\n",

-      "Xb=80.##           (T1-T2)=80b;so let (T1-T2)/b=Xb\n",

-      "Y=e**(U*THETA)##    LET Y=T1/T2\n",

-      "Zb=80.*Y/(Y-1.)##   LET  T1/b=Zb;BY SOLVING THE ABOVE 2 EQUATIONS WE WILL GET THIS EXPRESSION\n",

-      "Mb=t*L*density*10**-2.## m/b in N\n",

-      "Tcb=Mb*V**2.##          centrifugal tension/b\n",

-      "Tmaxb=Zb+Tcb##         MAX TENSION/b\n",

-      "Fb=Tmaxb/t##STRESS INDUCED IN TIGHT BELT\n",

-      "\n",

-      "##OUTPUT\n",

-      "print'%s %.1f %s'%('THE STRESS DEVELOPED ON THE TIGHT SIDE OF BELT=',Fb,' N/cm**2')\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "THE STRESS DEVELOPED ON THE TIGHT SIDE OF BELT= 37.8  N/cm**2\n"

-       ]

-      }

-     ],

-     "prompt_number": 11

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex11-pg65"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 2,ILLUSTRATION 11 PAGE 65\n",

-      "##TITLE:TRANSMISSION OF MOTION AND POWER BY BELTS AND PULLEYS\n",

-      "import math\n",

-      "##INPUT\n",

-      "C=4.5##      CENTRE DISTANCE IN metres\n",

-      "D1=1.35##    DIAMETER OF LARGER PULLEY IN metres\n",

-      "D2=.9##      DIAMETER OF SMALLER PULLEY IN metres\n",

-      "To=2100.##    INITIAL TENSION IN newtons\n",

-      "b=12.##       WIDTH OF BELT IN cm\n",

-      "t=12.##       THICKNESS OF BELT IN mm\n",

-      "d=1.##        DENSITY IN gm/cm**3\n",

-      "U=.3##       COEFFICIENT OF FRICTION\n",

-      "L=1.##        length in metres\n",

-      "PI=3.141\n",

-      "e=2.71\n",

-      "\n",

-      "##CALCULATION\n",

-      "M=b*t*d*L*10**-2.##               mass of belt per metre length in KG\n",

-      "V=(To/3./M)**.5##                 VELOCITY OF FOR MAX POWER TO BE TRANSMITTED IN m/s\n",

-      "Tc=M*V**2.##                      CENTRIFUGAL TENSION IN newtons\n",

-      "##                              LET (T1+T2)=X\n",

-      "X=2.*To-2.*Tc   ##                THE VALUE OF (T1+T2)\n",

-      "F=(D1-D2)/(2.*C)\n",

-      "ALPHA=math.asin(F/57.3)\n",

-      "THETA=(180.-(2.*ALPHA))*PI/180.##   ANGLE OF CONTACT IN radians\n",

-      "##                               LET T1/T2=Y\n",

-      "Y=e**(U*THETA)##                  THE VALUE OF T1/T2\n",

-      "T1=X*Y/(Y+1.)##                   BY SOLVING X AND Y WE WILL GET THIS EQN\n",

-      "T2=X-T1\n",

-      "P=(T1-T2)*V/1000.##                 MAX POWER TRANSMITTED IN kilowatts\n",

-      "N1=V*60./(PI*D1)##                   SPEED OF LARGER PULLEY IN rpm\n",

-      "N2=V*60./(PI*D2)##                   SPEED OF SMALLER PULLEY IN rpm\n",

-      "##OUTPUT\n",

-      "print'%s %.1f %s'%(' MAX POWER TO BE TRANSMITTED =',P,' KW')\n",

-      "print'%s %.1f %s'%(' SPEED OF THE LARGER PULLEY =',N1,' rpm')\n",

-      "print'%s %.1f %s'%(' SPEED OF THE SMALLER PULLEY =',N2,' rpm')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        " MAX POWER TO BE TRANSMITTED = 27.0  KW\n",

-        " SPEED OF THE LARGER PULLEY = 312.0  rpm\n",

-        " SPEED OF THE SMALLER PULLEY = 468.0  rpm\n"

-       ]

-      }

-     ],

-     "prompt_number": 12

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex12-pg66"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 2,ILLUSTRATION 12 PAGE 66\n",

-      "##TITLE:TRANSMISSION OF MOTION AND POWER BY BELTS AND PULLEYS\n",

-      "import math\n",

-      "##============================================================================================================================\n",

-      "##INPUT\n",

-      "PI=3.141\n",

-      "e=2.71\n",

-      "D1=1.20##               DIAMETER OF DRIVING SHAFT IN m\n",

-      "D2=.50##                DIAMETER OF DRIVEN SHAFT IN m\n",

-      "C=4.##                   CENTRE DISTANCE BETWEEN THE SHAFTS IN m\n",

-      "M=.9##                  MASS OF BELT PER METRE LENGTH IN kg\n",

-      "Tmax=2000##             MAX TENSION IN N\n",

-      "U=.3##                  COEFFICIENT OF FRICTION\n",

-      "N1=200.##                SPEED  OF DRIVING SHAFT IN rpm\n",

-      "N2=450.##                SPEED OF DRIVEN SHAFT IN rpm\n",

-      "##==============================================================================================================================\n",

-      "##CALCULATION\n",

-      "V=PI*D1*N1/60.##         VELOCITY OF BELT IN m/s\n",

-      "Tc=M*V**2.##              CENTRIFUGAL TENSION IN N\n",

-      "T1=Tmax-Tc##            TENSION ON TIGHTSIDE IN N\n",

-      "F=(D1-D2)/(2.*C)\n",

-      "ALPHA=math.asin(F/57.3)\n",

-      "THETA=(180.-(2.*ALPHA))*PI/180.##   ANGLE OF CONTACT IN radians\n",

-      "T2=T1/(e**(U*THETA))##            TENSION ON SLACK SIDE IN N\n",

-      "TL=(T1-T2)*D1/2.##                TORQUE ON THE SHAFT OF LARGER PULLEY IN N-m\n",

-      "TS=(T1-T2)*D2/2.##                TORQUE ON THE SHAFT OF SMALLER PULLEY IN N-m\n",

-      "P=(T1-T2)*V/1000.##               POWER TRANSMITTED IN kW\n",

-      "Pi=2.*PI*N1*TL/60000.##            INPUT POWER\n",

-      "Po=2.*PI*N2*TS/60000.##            OUTPUT POWER\n",

-      "Pl=Pi-Po##                       POWER LOST DUE TO FRICTION IN kW\n",

-      "n=Po/Pi*100.##                    EFFICIENCY OF DRIVE IN %\n",

-      "##==================================================================================================================================\n",

-      "##OUTPUT\n",

-      "print'%s %.1f %s'%('TORQUE ON LARGER SHAFT =',TL,'N-m')\n",

-      "print'%s %.1f %s'%('TORQUE ON SMALLER SHAFT =',TS,' N-m')\n",

-      "print'%s %.1f %s'%('POWER TRANSMITTED =',P,' kW')\n",

-      "print'%s %.1f %s'%('POWER LOST DUE TO FRICTION =',Pl,' kW')\n",

-      "print'%s %.1f %s'%('EFFICIENCY OF DRINE =',n,' percentage')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "TORQUE ON LARGER SHAFT = 679.0 N-m\n",

-        "TORQUE ON SMALLER SHAFT = 282.9  N-m\n",

-        "POWER TRANSMITTED = 14.2  kW\n",

-        "POWER LOST DUE TO FRICTION = 0.9  kW\n",

-        "EFFICIENCY OF DRINE = 93.8  percentage\n"

-       ]

-      }

-     ],

-     "prompt_number": 14

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex13-pg67"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 2,ILLUSTRATION 13 PAGE 67\n",

-      "##TITLE:TRANSMISSION OF MOTION AND POWER BY BELTS AND PULLEYS\n",

-      "import math\n",

-      "##============================================================================================================================\n",

-      "##INPUT\n",

-      "PI=3.141\n",

-      "e=2.71\n",

-      "P=90##                      POWER OF A COMPRESSOR IN kW\n",

-      "N2=250.##                   SPEED OF DRIVEN SHAFT IN rpm\n",

-      "N1=750.##                   SPEED OF DRIVER SHAFT IN rpm\n",

-      "D2=1.##                     DIAMETER OF DRIVEN SHAFT IN m\n",

-      "C=1.75##                    CENTRE DISTANCE IN m\n",

-      "V=1600./60.##                 VELOCITY IN m/s\n",

-      "a=375.##                     CROSECTIONAL AREA IN mm**2\n",

-      "density=1000.##              BELT DENSITY IN kg/m**3\n",

-      "L=1##                       length to be considered\n",

-      "Fb=2.5##                    STRESSS INDUCED IN MPa\n",

-      "beeta=35./2.##                THE GROOVE ANGLE OF PULLEY\n",

-      "U=.25##                     COEFFICIENT OF FRICTION\n",

-      "##=================================================================================================================================\n",

-      "##CALCULATION\n",

-      "D1=N2*D2/N1##               DIAMETER OF DRIVING SHAFT IN m\n",

-      "m=a*density*10**-6.*L##       MASS OF THE BELT IN kg\n",

-      "Tmax=a*Fb##                 MAX TENSION IN N\n",

-      "Tc=m*V**2.##                  CENTRIFUGAL TENSION IN N\n",

-      "T1=Tmax-Tc##                TENSION ON TIGHTSIDE OF BELT IN N\n",

-      "F=(D2-D1)/(2.*C)\n",

-      "ALPHA=math.asin(F/57.3)\n",

-      "THETA=(180.-(2.*ALPHA))*PI/180.##   ANGLE OF CONTACT IN radians\n",

-      "T2=T1/(e**(U*THETA/math.sin(beeta/57.3)))##TENSION ON SLACKSIDE IN N\n",

-      "P2=(T1-T2)*V/1000.##              POWER TRANSMITTED PER BELT kW\n",

-      "N=P/P2##                          NO OF V-BELTS\n",

-      "N3=N+1.\n",

-      "##======================================================================================================================================\n",

-      "##OUTPUT\n",

-      "print'%s %.1f %s %.1f %s '%('NO OF BELTS REQUIRED TO TRANSMIT POWER=',N,' APPROXIMATELY=',N3,'')\n",

-      "\n",

-      "\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "NO OF BELTS REQUIRED TO TRANSMIT POWER= 5.4  APPROXIMATELY= 6.4  \n"

-       ]

-      }

-     ],

-     "prompt_number": 15

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex14-pg68"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 2,ILLUSTRATION 14 PAGE 68\n",

-      "##TITLE:TRANSMISSION OF MOTION AND POWER BY BELTS AND PULLEYS\n",

-      "import math\n",

-      "##============================================================================================================================\n",

-      "##INPUT\n",

-      "PI=3.141\n",

-      "e=2.71\n",

-      "P=75.##             POWER IN kW\n",

-      "D=1.5##            DIAMETER OF PULLEY IN m\n",

-      "U=.3##             COEFFICIENT OF FRICTION\n",

-      "beeta=45./2.##       GROOVE ANGLE\n",

-      "THETA=160.*PI/180.## ANGLE OF CONTACT IN radians\n",

-      "m=.6##             MASS OF BELT IN kg/m\n",

-      "Tmax=800.##         MAX TENSION IN N\n",

-      "N=200.##            SPEED OF SHAFT IN rpm\n",

-      "##=============================================================================================================================\n",

-      "##calculation\n",

-      "V=PI*D*N/60.##               VELOCITY OF ROPE IN m/s\n",

-      "Tc=m*V**2.##                  CENTRIFUGAL TENSION IN N\n",

-      "T1=Tmax-Tc##                     TENSION ON TIGHT SIDE IN N\n",

-      "T2=T1/(e**(U*THETA/math.sin(beeta/57.3)))##TENSION ON SLACKSIDE IN N\n",

-      "P2=(T1-T2)*V/1000.##              POWER TRANSMITTED PER BELT kW\n",

-      "No=P/P2##                          NO OF V-BELTS\n",

-      "N3=No+1.##                           ROUNDING OFF\n",

-      "To=(T1+T2+Tc*2.)/2.##                 INITIAL TENSION\n",

-      "##================================================================================================================================\n",

-      "##OUTPUT\n",

-      "print'%s %.1f %s %.1f %s '%('NO OF BELTS REQUIRED TO TRANSMIT POWER=',No,'' 'APPROXIMATELY=',N3,'')\n",

-      "print'%s %.1f %s'%('INITIAL ROPE TENSION=',To,' N')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "NO OF BELTS REQUIRED TO TRANSMIT POWER= 8.3 APPROXIMATELY= 9.3  \n",

-        "INITIAL ROPE TENSION= 510.8  N\n"

-       ]

-      }

-     ],

-     "prompt_number": 16

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Theory_Of_Machines_by__B._K._Sarkar/Chapter3.ipynb b/_Theory_Of_Machines_by__B._K._Sarkar/Chapter3.ipynb
deleted file mode 100755
index 74818ab4..00000000
--- a/_Theory_Of_Machines_by__B._K._Sarkar/Chapter3.ipynb
+++ /dev/null
@@ -1,782 +0,0 @@
-{

- "metadata": {

-  "name": "",

-  "signature": "sha256:9f3aa65b257e3f2aa586660a443f5f27bf555a236ce21a3b4fb7b3ab1cf26f12"

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter3-FRICTION"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex1-pg102"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 3 ILLUSRTATION 1 PAGE NO 102\n",

-      "##TITLE:FRICTION\n",

-      "##FIRURE 3.16(a),3.16(b)\n",

-      "import math\n",

-      "##===========================================================================================\n",

-      "##INPUT DATA\n",

-      "P1=180.##                        PULL APPLIED TO THE BODY IN NEWTONS\n",

-      "theta=30.##                      ANGLE AT WHICH P IS ACTING IN DEGREES\n",

-      "P2=220.##                        PUSH APPLIED TO THE BODY IN NEWTONS\n",

-      "##Rn=                           NORMAL REACTION\n",

-      "##F=                            FORCE OF FRICTION IN NEWTONS\n",

-      "##U=                            COEFFICIENT OF FRICTION\n",

-      "##W=                            WEIGHT OF THE BODY IN NEWTON\n",

-      "##==========================================================================================\n",

-      "##CALCULATION\n",

-      "F1=P1*math.cos(theta/57.3)##              RESOLVING FORCES HORIZONTALLY FROM 3.16(a)\n",

-      "F2=P2*math.cos(theta/57.3)##              RESOLVING FORCES HORIZONTALLY FROM 3.16(b)\n",

-      "##                               RESOLVING FORCES VERTICALLY  Rn1=W-P1*sind(theta) from 3.16(a)\n",

-      "##                               RESOLVING FORCES VERTICALLY  Rn2=W+P1*sind(theta) from 3.16(b)\n",

-      "##                               USING THE RELATION F1=U*Rn1    &     F2=U*Rn2  AND SOLVING FOR W BY DIVIDING THESE TWO EQUATIONS\n",

-      "X=F1/F2##                        THIS IS THE VALUE OF   Rn1/Rn2\n",

-      "Y1=P1*math.sin(theta/57.3)\n",

-      "Y2=P2*math.sin(theta/57.3)\n",

-      "W=(Y2*X+Y1)/(1-X)##                BY SOLVING ABOVE 3 EQUATIONS\n",

-      "U=F1/(W-P1*math.sin(theta/57.3))##          COEFFICIENT OF FRICTION\n",

-      "##=============================================================================================\n",

-      "##OUTPUT\n",

-      "print'%s %.1f %s %.1f %s '%('WEIGHT OF THE BODY =',W,'N''THE COEFFICIENT OF FRICTION =',U,'')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "WEIGHT OF THE BODY = 989.9 NTHE COEFFICIENT OF FRICTION = 0.2  \n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex2-pg103"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 3 ILLUSRTATION 2 PAGE NO 103\n",

-      "##TITLE:FRICTION\n",

-      "##FIRURE 3.17\n",

-      "import math\n",

-      "##===========================================================================================\n",

-      "##INPUT DATA\n",

-      "THETA=45##                ANGLE OF INCLINATION IN DEGREES\n",

-      "g=9.81##                   ACCELERATION DUE TO GRAVITY IN N/mm**2\n",

-      "U=.1##                     COEFFICIENT FRICTION\n",

-      "##Rn=NORMAL REACTION\n",

-      "##M=MASS IN NEWTONS\n",

-      "##f=ACCELERATION OF THE BODY\n",

-      "u=0.##                      INITIAL VELOCITY\n",

-      "V=10.##                     FINAL VELOCITY IN m/s**2\n",

-      "##===========================================================================================\n",

-      "##CALCULATION\n",

-      "##CONSIDER THE EQUILIBRIUM OF FORCES PERPENDICULAR TO THE PLANE\n",

-      "##Rn=Mgcos(THETA)\n",

-      "##CONSIDER THE EQUILIBRIUM OF FORCES ALONG THE PLANE\n",

-      "##Mgsin(THETA)-U*Rn=M*f.............BY SOLVING THESE 2 EQUATIONS \n",

-      "f=g*math.sin(THETA/57.3)-U*g*math.cos(THETA/57.3)\n",

-      "s=(V**2-u**2)/(2*f)##                  DISTANCE ALONG THE PLANE IN metres\n",

-      "##==============================================================================================\n",

-      "##OUTPUT\n",

-      "print'%s %.1f %s'%('DISTANCE ALONG THE INCLINED PLANE=',s,' m')\n",

-      "\n",

-      "\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "DISTANCE ALONG THE INCLINED PLANE= 8.0  m\n"

-       ]

-      }

-     ],

-     "prompt_number": 2

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex3-pg104"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 3 ILLUSRTATION 3 PAGE NO 104\n",

-      "##TITLE:FRICTION\n",

-      "##FIRURE 3.18\n",

-      "import math\n",

-      "##===========================================================================================\n",

-      "##INPUT DATA\n",

-      "W=500.##                  WEGHT IN NEWTONS\n",

-      "THETA=30.##               ANGLE OF INCLINATION IN DEGRESS\n",

-      "U=0.2##                  COEFFICIENT FRICTION\n",

-      "S=15.##                   DISTANCE IN metres\n",

-      "##============================================================================================\n",

-      "Rn=W*math.cos(THETA/57.3)##       NORMAL REACTION IN NEWTONS\n",

-      "P=W*math.sin(THETA/57.3)+U*Rn##   PUSHING FORCE ALONG THE DIRECTION OF MOTION\n",

-      "w=P*S\n",

-      "##============================================================================================\n",

-      "##OUTPUT\n",

-      "print'%s %.1f %s'%('WORK DONE BY THE FORCE=',w,' N-m')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "WORK DONE BY THE FORCE= 5048.8  N-m\n"

-       ]

-      }

-     ],

-     "prompt_number": 3

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex4-pg104"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 3 ILLUSRTATION 4 PAGE NO 104\n",

-      "##TITLE:FRICTION\n",

-      "##FIRURE 3.19(a)  &  3.19(b)\n",

-      "import math\n",

-      "##===========================================================================================\n",

-      "##INPUT DATA\n",

-      "P1=2000.##           FORCE ACTING UPWARDS WHEN ANGLE=15 degrees IN NEWTONS\n",

-      "P2=2300.##           FORCE ACTING UPWARDS WHEN ANGLE=20 degrees IN NEWTONS\n",

-      "THETA1=15.##         ANGLE OF INCLINATION IN 3.19(a)\n",

-      "THETA2=20.##         ANGLE OF INCLINATION IN 3.19(b)\n",

-      "##F1=               FORCE OF FRICTION IN 3.19(a)\n",

-      "##Rn1=              NORMAL REACTION IN 3.19(a)\n",

-      "##F2=               FORCE OF FRICTION IN 3.19(b)\n",

-      "##Rn2=              NORMAL REACTION IN 3.19(b)\n",

-      "##U=                 COEFFICIENT OF FRICTION\n",

-      "##===========================================================================================\n",

-      "##CALCULATION\n",

-      "##P1=F1+Rn1             RESOLVING THE FORCES ALONG THE PLANE\n",

-      "##Rn1=W*cosd(THETA1)....NORMAL REACTION IN 3.19(a)\n",

-      "##F1=U*Rn1\n",

-      "##BY SOLVING ABOVE EQUATIONS P1=W(U*cosd(THETA1)+sind(THETA1))---------------------1\n",

-      "##P2=F2+Rn2             RESOLVING THE FORCES PERPENDICULAR TO THE PLANE\n",

-      "##Rn2=W*cosd(THETA2)....NORMAL REACTION IN 3.19(b)\n",

-      "##F2=U*Rn2\n",

-      "##BY SOLVING ABOVE EQUATIONS P2=W(U*cosd(THETA2)+sind(THETA2))----------------------2\n",

-      "##BY SOLVING EQUATIONS 1 AND 2\n",

-      "X=P2/P1\n",

-      "U=(math.sin(THETA2/57.3)-(X*math.sin(THETA1/57.3)))/((X*math.cos(THETA1/57.3)-math.cos(THETA2/57.3)))##        COEFFICIENT OF FRICTION\n",

-      "W=P1/(U*math.cos(THETA1/57.3)+math.sin(THETA1/57.3))\n",

-      "##=============================================================================================\n",

-      "##OUTPUT\n",

-      "##print'%s %.1f %s'%('%f',X)\n",

-      "print'%s %.1f %s  %.1f %s '%('COEFFICIENT OF FRICTION=',U,'' 'WEIGHT OF THE BODY=',W,' N')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "COEFFICIENT OF FRICTION= 0.3 WEIGHT OF THE BODY=  3927.0  N \n"

-       ]

-      }

-     ],

-     "prompt_number": 4

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex5-pg105"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 3 ILLUSRTATION 5 PAGE NO 105\n",

-      "##TITLE:FRICTION\n",

-      "import math\n",

-      "##===========================================================================================\n",

-      "##INPUT DATA\n",

-      "d=5.##                     DIAMETER OF SCREW JACK IN cm\n",

-      "p=1.25##                  PITCH IN cm\n",

-      "l=50.##                    LENGTH IN cm\n",

-      "U=.1##                    COEFFICIENT OF FRICTION\n",

-      "W=20000.##                 LOAD IN NEWTONS\n",

-      "PI=3.147\n",

-      "##=============================================================================================\n",

-      "##CALCULATION\n",

-      "ALPHA=math.atan((p/(PI*d)/57.3))\n",

-      "PY=math.atan(U/57.3)\n",

-      "P=W*math.tan((ALPHA+PY)*57.)\n",

-      "P1=P*d/(2.*l)\n",

-      "##=============================================================================================\n",

-      "##OUTPUT\n",

-      "print'%s %.1f %s '%('THE AMOUNT OF EFFORT NEED TO APPLY =',P1,' N')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "THE AMOUNT OF EFFORT NEED TO APPLY = 180.4  N \n"

-       ]

-      }

-     ],

-     "prompt_number": 5

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex6-pg106"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 3 ILLUSRTATION 6 PAGE NO 106\n",

-      "##TITLE:FRICTION\n",

-      "import math\n",

-      "##===========================================================================================\n",

-      "##INPUT DATA\n",

-      "d=50.##                 DIAMETER OF SCREW IN mm\n",

-      "p=12.5##               PITCH IN mm\n",

-      "U=0.13##               COEFFICIENT OF FRICTION\n",

-      "W=25000.##              LOAD IN mm\n",

-      "PI=3.147\n",

-      "##===========================================================================================\n",

-      "##CALCULATION\n",

-      "ALPHA=math.atan((p/(PI*d))/57.3)\n",

-      "PY=math.atan(U/57.3)\n",

-      "P=W*math.tan((ALPHA+PY)/57.3)##         FORCE REQUIRED TO RAISE THE LOAD IN N\n",

-      "T1=P*d/2.##                   TORQUE REQUIRED IN Nm\n",

-      "P1=W*math.tan((PY-ALPHA)/57.3)##        FORCE REQUIRED TO LOWER THE SCREW IN N\n",

-      "T2=P1*d/2.##                  TORQUE IN N\n",

-      "X=T1/T2##                     RATIOS REQUIRED\n",

-      "n=math.tan((ALPHA/(ALPHA+PY))/57.3)##    EFFICIENCY\n",

-      "##============================================================================================\n",

-      "print'%s %.1f %s'%('RATIO OF THE TORQUE REQUIRED TO RAISE THE LOAD,TO THE TORQUE REQUIRED TO LOWER THE LOAD =',X,'')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "RATIO OF THE TORQUE REQUIRED TO RAISE THE LOAD,TO THE TORQUE REQUIRED TO LOWER THE LOAD = 4.1 \n"

-       ]

-      }

-     ],

-     "prompt_number": 6

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex7-pg107"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 3 ILLUSRTATION 7 PAGE NO 107\n",

-      "##TITLE:FRICTION\n",

-      "import math\n",

-      "##===========================================================================================\n",

-      "##INPUT DATA\n",

-      "d=39.##                 DIAMETER OF THREAD IN mm\n",

-      "p=13.##                 PITCH IN mm\n",

-      "U=0.1##                COEFFICIENT OF FRICTION\n",

-      "W=2500.##               LOAD IN mm\n",

-      "PI=3.147\n",

-      "##===========================================================================================\n",

-      "##CALCULATION\n",

-      "ALPHA=math.atan((p/(PI*d))/57.3)\n",

-      "PY=math.atan(U/57.3)\n",

-      "P=W*math.tan((ALPHA+PY)*57.3)##         FORCE IN N\n",

-      "T1=P*d/2.##                   TORQUE REQUIRED IN Nm\n",

-      "T=2.*T1##                      TORQUE REQUIRED ON THE COUPLING ROD IN Nm\n",

-      "K=2.*p##                      DISTANCE TRAVELLED FOR ONE REVOLUTION\n",

-      "N=20.8/K##                   NO OF REVOLUTIONS REQUIRED\n",

-      "w=2.*PI*N*T/100.##                 WORKDONE BY TORQUE\n",

-      "w1=w*(7500.-2500.)/2500.##      WORKDONE TO INCREASE THE LOAD FROM 2500N TO 7500N\n",

-      "n=math.tan(ALPHA/57.3)/math.tan((ALPHA+PY)/57.3)##    EFFICIENCY\n",

-      "##============================================================================================\n",

-      "##OUTPUT\n",

-      "print'%s %.1f %s %.1f %s %.1f %s '%('workdone against a steady load of 2500N=',w,' N' 'workdone if the load is increased from 2500N to 7500N=',w1,' N' 'efficiency=',n,'')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "workdone against a steady load of 2500N= 1025.5  Nworkdone if the load is increased from 2500N to 7500N= 2050.9  Nefficiency= 0.5  \n"

-       ]

-      }

-     ],

-     "prompt_number": 7

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex8-pg107"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 3 ILLUSRTATION 8 PAGE NO 107\n",

-      "##TITLE:FRICTION\n",

-      "import math\n",

-      "##===========================================================================================\n",

-      "##INPUT DATA\n",

-      "W=50000.##                        WEIGHT OF THE SLUICE GATE IN NEWTON\n",

-      "P=40000.##                        POWER IN WATTS\n",

-      "N=580.##                          MAX MOTOR RUNNING SPEEED IN rpm\n",

-      "d=12.5##                         DIAMETER OF THE SCREW IN cm\n",

-      "p=2.5##                          PITCH IN cm\n",

-      "PI=3.147\n",

-      "U1=.08##                          COEFFICIENT OF FRICTION for SCREW\n",

-      "U2=.1##                           C.O.F BETWEEN GATES AND SCREW\n",

-      "Np=2000000.##                     NORMAL PRESSURE IN NEWTON\n",

-      "Fl=.15##                       FRICTION LOSS\n",

-      "n=1.-Fl##                       EFFICIENCY\n",

-      "ng=80.##                        NO OF TEETH ON GEAR\n",

-      "##===========================================================================================\n",

-      "##CALCULATION\n",

-      "TV=W+U2*Np##                     TOTAL VERTICAL HEAD IN NEWTON\n",

-      "ALPHA=math.atan((p/(PI*d))/57.3)##         \n",

-      "PY=math.atan(U1/57.3)##                 \n",

-      "P1=TV*math.tan((ALPHA+PY)*57.3)##            FORCE IN N\n",

-      "T=P1*d/2./100.##                    TORQUE IN N-m\n",

-      "Ng=60000.*n*P*10**-3./(2.*PI*T)##              SPEED OF GEAR IN rpm\n",

-      "np=Ng*ng/N##                       NO OF TEETH ON PINION\n",

-      "##=========================================================================================\n",

-      "##OUTPUT\n",

-      "print'%s %.1f %s %.1f %s '%('NO OF TEETH ON PINION =',np,' say ',np+1,'')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "NO OF TEETH ON PINION = 19.8  say  20.8  \n"

-       ]

-      }

-     ],

-     "prompt_number": 8

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex9-pg108"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 3 ILLUSRTATION 9 PAGE NO 108\n",

-      "##TITLE:FRICTION\n",

-      "import math\n",

-      "##===========================================================================================\n",

-      "##INPUT DATA\n",

-      "d=5.##                         MEAN DIAMETER OF SCREW IN cm\n",

-      "p=1.25##                      PITCH IN cm\n",

-      "W=10000.##                     LOAD AVAILABLE IN NEWTONS\n",

-      "dc=6.##                        MEAN DIAMETER OF COLLAR IN cm\n",

-      "U=.15##                       COEFFICIENT OF FRICTION OF SCREW\n",

-      "Uc=.18##                      COEFFICIENT OF FRICTION OF COLLAR\n",

-      "P1=100.##                      TANGENTIAL FORCE APPLIED IN NEWTON\n",

-      "PI=3.147\n",

-      "##============================================================================================\n",

-      "##CALCULATION\n",

-      "ALPHA=math.atan((p/(PI*d))/57.3)##         \n",

-      "PY=math.atan(U/57.3)##                 \n",

-      "T1=W*d/2*math.tan((ALPHA+PY)/100)*57.3##         TORQUE ON SCREW IN NEWTON\n",

-      "Tc=Uc*W*dc/2./100.##                      TORQUE ON COLLAR IN NEWTON\n",

-      "T=T1+Tc##                          TOTAL TORQUE\n",

-      "D=2.*T/P1/2.*100.##                       DIAMETER OF HAND WHEEL IN cm\n",

-      "##============================================================================================\n",

-      "##OUTPUT\n",

-      "print'%s %.1f %s'%('SUITABLE DIAMETER OF HAND WHEEL =',D,' cm')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "SUITABLE DIAMETER OF HAND WHEEL = 111.4  cm\n"

-       ]

-      }

-     ],

-     "prompt_number": 9

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex10-pg108"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 3 ILLUSRTATION 10 PAGE NO 108\n",

-      "##TITLE:FRICTION\n",

-      "import math\n",

-      "##===========================================================================================\n",

-      "##INPUT DATA\n",

-      "PI=3.147\n",

-      "d=2.5##                    MEAN DIA OF BOLT IN cm\n",

-      "p=.6##                     PITCH IN cm\n",

-      "beeta=55/2.##               VEE ANGLE\n",

-      "dc=4.##                     DIA OF COLLAR IN cm\n",

-      "U=.1##                       COEFFICIENT OF FRICTION OF BOLT\n",

-      "Uc=.18##                      COEFFICIENT OF FRICTION OF COLLAR\n",

-      "W=6500.##                     LOAD ON BOLT IN NEWTONS\n",

-      "L=38.##                       LENGTH OF SPANNER\n",

-      "##=============================================================================================\n",

-      "##CALCULATION\n",

-      "##LET X=tan(py)/tan(beeta)\n",

-      "##y=tan(ALPHA)*X\n",

-      "PY=math.atan(U)*57.3\n",

-      "ALPHA=math.atan((p/(PI*d)))*57.3\n",

-      "X=math.tan(PY/57.3)/math.cos(beeta/57.3)\n",

-      "Y=math.tan(ALPHA/57.3)\n",

-      "T1=W*d/2.*10**-2*(X+Y)/(1.-(X*Y))##             TORQUE IN SCREW IN N-m\n",

-      "Tc=Uc*W*dc/2.*10**-2##                         TORQUE ON BEARING SERVICES IN N-m\n",

-      "T=T1+Tc##                                     TOTAL TORQUE \n",

-      "P1=T/L*100.##                                      FORCE REQUIRED BY @ THE END OF SPANNER\n",

-      "##=============================================================================================\n",

-      "##OUTPUT\n",

-      "print'%s %.1f %s'%('FORCE REQUIRED @ THE END OF SPANNER=',P1,' N')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "FORCE REQUIRED @ THE END OF SPANNER= 102.3  N\n"

-       ]

-      }

-     ],

-     "prompt_number": 10

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex11-pg109"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 3 ILLUSRTATION 11 PAGE NO 109\n",

-      "##TITLE:FRICTION\n",

-      "import math\n",

-      "##===========================================================================================\n",

-      "##INPUT DATA\n",

-      "d1=15.##                                 DIAMETER OF VERTICAL SHAFT IN cm\n",

-      "N=100.##                                 SPEED OF THE MOTOR rpm\n",

-      "W=20000.##                                LOAD AVILABLE IN N\n",

-      "U=.05##                                  COEFFICIENT OF FRICTION\n",

-      "PI=3.147\n",

-      "##==================================================================================\n",

-      "T=2./3.*U*W*d1/2.##                         FRICTIONAL TORQUE IN N-m\n",

-      "PL=2.*PI*N*T/100./60.##                         POWER LOST IN FRICTION IN WATTS\n",

-      "##==================================================================================\n",

-      "##OUTPUT\n",

-      "print'%s %.1f %s'%('POWER LOST IN FRICTION=',PL,' watts')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "POWER LOST IN FRICTION= 524.5  watts\n"

-       ]

-      }

-     ],

-     "prompt_number": 11

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex12-pg109"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 3 ILLUSRTATION 12 PAGE NO 109\n",

-      "##TITLE:FRICTION\n",

-      "import math\n",

-      "##===================================================================================\n",

-      "##INPUT DATA\n",

-      "PI=3.147\n",

-      "d2=.30##                             DIAMETER OF SHAFT IN m \n",

-      "W=200000.##                           LOAD AVAILABLE IN NEWTONS\n",

-      "N=75.##                              SPEED IN rpm\n",

-      "U=.05##                             COEFFICIENT OF FRICTION\n",

-      "p=300000.##                          PRESSURE AVAILABLE IN N/m**2\n",

-      "P=16200.##                           POWER LOST DUE TO FRICTION IN WATTS\n",

-      "##====================================================================================\n",

-      "##CaLCULATION\n",

-      "T=P*60./2./PI/N##                      TORQUE INDUCED IN THE SHFT IN N-m\n",

-      "##LET X=(r1**3-r2**3)/(r1**2-r2**2)\n",

-      "X=(3./2.*T/U/W)\n",

-      "r2=.15##                             SINCE d2=.30 m\n",

-      "c=r2**2.-(X*r2)\n",

-      "b= r2-X\n",

-      "a= 1.\n",

-      "r1=( -b+ math.sqrt (b**2. -4.*a*c ))/(2.* a);##     VALUE OF r1 IN m\n",

-      "d1=2*r1*100.##                               d1 IN cm\n",

-      "n=W/(PI*p*(r1**2.-r2**2.))\n",

-      "##================================================================================\n",

-      "##OUTPUT\n",

-      "print'%s %.1f %s %.1f %s %.1f %s'%('EXTERNAL DIAMETER OF SHAFT =',d1,' cm''NO OF COLLARS REQUIRED =',n,'' '0 or ',n+1,'')\n",

-      "\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "EXTERNAL DIAMETER OF SHAFT = 50.6  cmNO OF COLLARS REQUIRED = 5.1 0 or  6.1 \n"

-       ]

-      }

-     ],

-     "prompt_number": 12

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex13-pg111"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 3 ILLUSRTATION 13 PAGE NO 111\n",

-      "##TITLE:FRICTION\n",

-      "import math\n",

-      "##===================================================================================\n",

-      "##INPUT DATA\n",

-      "PI=3.147\n",

-      "W=20000.##                                LOAD IN NEWTONS\n",

-      "ALPHA=120./2.##                               CONE ANGLE IN DEGREES\n",

-      "p=350000.##                                INTENSITY OF PRESSURE\n",

-      "U=.06\n",

-      "N=120.##                                    SPEED OF THE SHAFT IN rpm\n",

-      "##d1=3d2\n",

-      "##r1=3r2\n",

-      "##===================================================================================\n",

-      "##CALCULATION\n",

-      "##LET K=d1/d2\n",

-      "k=3.\n",

-      "Z=W/((k**2.-1.)*PI*p)\n",

-      "r2=Z**.5##                                  INTERNAL RADIUS IN m\n",

-      "r1=3.*r2\n",

-      "T=2.*U*W*(r1**3.-r2**3.)/(3.*math.sin(60/57.3)*(r1**2.-r2**2.))##     total frictional torque in N\n",

-      "P=2.*PI*N*T/60000.##                            power absorbed in friction in kW\n",

-      "##================================================================================\n",

-      "print'%s %.1f %s %.1f %s %.1f %s'%('THE INTERNAL DIAMETER OF SHAFT =',r2*100,' cm' 'THE EXTERNAL DIAMETER OF SHAFT =',r1*100,' cm' 'POWER ABSORBED IN FRICTION =',P,' kW')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "THE INTERNAL DIAMETER OF SHAFT = 4.8  cmTHE EXTERNAL DIAMETER OF SHAFT = 14.3  cmPOWER ABSORBED IN FRICTION = 1.8  kW\n"

-       ]

-      }

-     ],

-     "prompt_number": 13

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex14-pg111"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 3 ILLUSRTATION 14 PAGE NO 111\n",

-      "##TITLE:FRICTION\n",

-      "import math\n",

-      "##===========================================================================================\n",

-      "##INPUT DATA\n",

-      "PI=3.147\n",

-      "P=10000.##                               POWER TRRANSMITTED BY CLUTCH IN WATTS\n",

-      "N=3000.##                                SPEED IN rpm\n",

-      "p=.09##                                 AXIAL PRESSURE IN N/mm**2\n",

-      "##d1=1.4d2                              RELATION BETWEEN DIAMETERS \n",

-      "K=1.4##                                 D1/D2\n",

-      "n=2.\n",

-      "U=.3##                                  COEFFICIENT OF FRICTION\n",

-      "##==========================================================================================\n",

-      "T=P*60000./1000./(2.*PI*N)##                     ASSUMING UNIFORM WEAR            TORQUE IN N-m\n",

-      "r2=(T*2./(n*U*2.*PI*p*10**6.*(K-1.)*(K+1.)))**(1./3.)##            INTERNAL RADIUS\n",

-      "\n",

-      "##===========================================================================================\n",

-      "print'%s %.1f %s %.1f %s '%('THE INTERNAL RADIUS =',r2*100,' cm' 'THE EXTERNAL RADIUS =',K*r2*100,' cm')\n",

-      " \n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "THE INTERNAL RADIUS = 5.8  cmTHE EXTERNAL RADIUS = 8.1  cm \n"

-       ]

-      }

-     ],

-     "prompt_number": 14

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex15-pg111"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 3 ILLUSRTATION 14 PAGE NO 111\n",

-      "##TITLE:FRICTION\n",

-      "\n",

-      "\n",

-      "\n",

-      "##===========================================================================================\n",

-      "##INPUT DATA\n",

-      "PI=3.147\n",

-      "n1=3.##                          NO OF DICS ON DRIVING SHAFTS\n",

-      "n2=2.##                          NO OF DICS ON DRIVEN SHAFTS\n",

-      "d1=30.##                         DIAMETER OF DRIVING SHAFT IN cm\n",

-      "d2=15.##                         DIAMETER OF DRIVEN SHAFT IN cm\n",

-      "r1=d1/2.\n",

-      "r2=d2/2.\n",

-      "U=.3##                          COEFFICIENT FRICTION\n",

-      "P=30000.##                       TANSMITTING POWER IN WATTS\n",

-      "N=1800.##                        SPEED IN rpm\n",

-      "##===========================================================================================\n",

-      "##CALCULATION\n",

-      "n=n1+n2-1.##                     NO OF PAIRS OF CONTACT SURFACES\n",

-      "T=P*60000./(2.*PI*N)##            TORQUE IN N-m\n",

-      "W=2.*T/(n*U*(r1+r2)*10.)##           LOAD IN N\n",

-      "k=W/(2.*PI*(r1-r2))\n",

-      "p=k/r2/100.##                        MAX AXIAL INTENSITY OF PRESSURE IN N/mm**2\n",

-      "##===========================================================================================\n",

-      "## OUTPUT\n",

-      "print'%s %.3f %s'%('MAX AXIAL INTENSITY OF PRESSURE =',p,' N/mm^2')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "MAX AXIAL INTENSITY OF PRESSURE = 0.033  N/mm**2\n"

-       ]

-      }

-     ],

-     "prompt_number": 15

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Theory_Of_Machines_by__B._K._Sarkar/Chapter4.ipynb b/_Theory_Of_Machines_by__B._K._Sarkar/Chapter4.ipynb
deleted file mode 100755
index de08c088..00000000
--- a/_Theory_Of_Machines_by__B._K._Sarkar/Chapter4.ipynb
+++ /dev/null
@@ -1,946 +0,0 @@
-{

- "metadata": {

-  "name": "",

-  "signature": "sha256:fdf50666cfa70019db7241b6e1fb1e819c70fb9987ea0caadb1e777e93e7d898"

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter4-Gears and Gear Drivers"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex1-pg133"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##Chapter-4, Illustration 1, Page 133\n",

-      "##Title: Gears and Gear Drivers\n",

-      "##=============================================================================\n",

-      "import math\n",

-      "\n",

-      "##INPUT DATA\n",

-      "TA=48.;##Wheel A teeth\n",

-      "TB=30.;##Wheel B teeth\n",

-      "m=5.;##Module pitch in mm\n",

-      "phi=20.;##Pressure angle in degrees\n",

-      "add=m;##Addendum in mm\n",

-      "\n",

-      "##CALCULATIONS\n",

-      "R=(m*TA)/2.;##Pitch circle radius of wheel A in mm\n",

-      "RA=R+add;##Radius of addendum circle of wheel A in mm\n",

-      "r=(m*TB)/2.;##Pitch circle radius of wheel B in mm\n",

-      "rA=r+add;##Radius of addendum circle of wheel B in mm\n",

-      "lp=(math.sqrt((RA**2.)-((R**2.)*(math.cos(phi/57.3)**2.))))+(math.sqrt((rA**2.)-((r**2.)*(math.cos(phi/57.3)**2.))))-((R+r)*math.sin(phi/57.3));##Length of path of contact in mm\n",

-      "la=lp/math.cos(phi/57.3);##Length of arc of contact in mm\n",

-      "\n",

-      "##OUTPUT\n",

-      "print'%s %.1f %s'%('Length of arc of contact is ',la,' mm')\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "##================================END OF PROGRAM=============================================\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Length of arc of contact is  26.7  mm\n"

-       ]

-      }

-     ],

-     "prompt_number": 2

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex2-pg133"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##Chapter-4, Illustration 2, Page 133\n",

-      "##Title: Gears and Gear Drivers\n",

-      "##=============================================================================\n",

-      "import math\n",

-      "\n",

-      "##INPUT DATA\n",

-      "TA=40.;##Wheel A teeth\n",

-      "TB=TA;##Wheel B teeth\n",

-      "m=6.;##Module pitch in mm\n",

-      "phi=20.;##Pressure angle in degrees\n",

-      "pi=3.141\n",

-      "x=1.75;##Ratio of length of arc of contact to circular pitch\n",

-      "\n",

-      "##CALCULATIONS\n",

-      "Cp=m*pi;##Circular pitch in mm\n",

-      "R=(m*TA)/2.;##Pitch circle radius of wheel A in mm\n",

-      "r=R;##Pitch circle radius of wheel B in mm\n",

-      "la=x*Cp;##Length of arc of contact in mm\n",

-      "lp=la*math.cos(phi/57.3);##Length of path of contact in mm\n",

-      "RA=math.sqrt((((lp/2.)+(R*math.sin(phi/57.3)))**2.)+((R**2.)*(math.cos(phi/57.3))**2.));##Radius of addendum circle of each wheel in mm\n",

-      "add=RA-R;##Addendum in mm\n",

-      "\n",

-      "##OUTPUT\n",

-      "print'%s %.1f %s'%('Addendum of wheel is ',add,' mm')\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "##================================END OF PROGRAM=============================================\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Addendum of wheel is  6.1  mm\n"

-       ]

-      }

-     ],

-     "prompt_number": 4

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex3-pg134"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##Chapter-4, Illustration 3, Page 134\n",

-      "##Title: Gears and Gear Drivers\n",

-      "##=============================================================================\n",

-      "import math\n",

-      "\n",

-      "##INPUT DATA\n",

-      "TA=48.;##Gear teeth\n",

-      "TB=24.;##Pinion teeth\n",

-      "m=6.;##Module in mm\n",

-      "phi=20.;##Pressure angle in degrees\n",

-      "\n",

-      "##CALCULATIONS\n",

-      "r=(m*TB)/2.;##Pitch circle radius of pinion in mm\n",

-      "R=(m*TA)/2.;##Pitch circle radius of gear in mm\n",

-      "RA=math.sqrt(((((r*math.sin(phi/57.3))/2.)+(R*math.sin(phi/57.3)))**2.)+((R**2)*(math.cos(phi/57.3))**2));##Radius of addendum circle of gear in mm\n",

-      "rA=math.sqrt(((((R*math.sin(phi/57.3))/2.)+(r*math.sin(phi/57.3)))**2.)+((r**2)*(math.cos(phi/57.3))**2));##Radius of addendum circle of pinion in mm\n",

-      "addp=rA-r;##Addendum for pinion in mm\n",

-      "addg=RA-R;##Addendum for gear in mm\n",

-      "lp=((R+r)*math.sin(phi/57.3))/2.;##Length of path of contact in mm\n",

-      "la=lp/math.cos(phi/57.3);##Length of arc of contact in mm\n",

-      "\n",

-      "##OUTPUT\n",

-      "print'%s %.1f %s  %.1f %s   %.1f %s '%('Addendum for pinion is',addp,' mm' ' Addendum for gear is ',addg,' mm' ' Length of arc of contact is ',la,' mm')\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "##================================END OF PROGRAM=============================================\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Addendum for pinion is 11.7  mm Addendum for gear is   4.7  mm Length of arc of contact is    39.3  mm \n"

-       ]

-      }

-     ],

-     "prompt_number": 5

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex4-pg135"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##Chapter-4, Illustration 4, Page 135\n",

-      "##Title: Gears and Gear Drivers\n",

-      "##=============================================================================\n",

-      "import math\n",

-      "\n",

-      "##INPUT DATA\n",

-      "x=3.5;##Ratio of teeth of wheels\n",

-      "C=1.2;##Centre distance between axes in m\n",

-      "DP=4.4;##Diametrical pitch in cm\n",

-      "\n",

-      "##CALCULATIONS\n",

-      "D=2*C*100.;##Sum of diameters of wheels in cm\n",

-      "T=D*DP;##Sum of teeth of wheels\n",

-      "TB1=T/(x+1);##Teeth of wheel B\n",

-      "TB=math.floor(TB1);##Teeth of whhel B\n",

-      "TA=x*TB;##Teeth of wheel A\n",

-      "DA=TA/DP;##Diametral pitch of gear A in cm\n",

-      "DB=TB/DP;##Diametral pitch of gear B in cm\n",

-      "Ce=(DA+DB)/2.;##Exact centre distance between shafts in cm\n",

-      "TB2=math.ceil(TB1);##Teeth of wheel B\n",

-      "TA2=T-TB2;##Teeth of wheel A\n",

-      "VR=TA2/TB2;##Velocity ratio\n",

-      "\n",

-      "##OUTPUT\n",

-      "print'%s %.1f %s %.1f %s %.1f %s%.1f %s%.1f %s'%('Number of teeth on wheel A is ',TA,''  'Number of teeth on wheel B is ',TB,''  '  Exact centre distance is ',Ce,' cm '  'If centre distance is ',C,' m' 'then  Velocity ratio is',VR,'')\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "##================================END OF PROGRAM=============================================\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Number of teeth on wheel A is  819.0 Number of teeth on wheel B is  234.0   Exact centre distance is  119.7  cm If centre distance is 1.2  mthen  Velocity ratio is3.5 \n"

-       ]

-      }

-     ],

-     "prompt_number": 6

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex5-pg136"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##Chapter-4, Illustration 5, Page 136\n",

-      "##Title: Gears and Gear Drivers\n",

-      "##=============================================================================\n",

-      "import math\n",

-      "\n",

-      "##INPUT DATA\n",

-      "C=600;##Distance between shafts in mm\n",

-      "Cp=30;##Circular pitch in mm\n",

-      "NA=200;##Speed of wheel A in rpm\n",

-      "NB=600;##Speed of wheel B in rpm\n",

-      "F=18;##Tangential pressure in kN\n",

-      "pi=3.141\n",

-      "\n",

-      "##CALCULATIONS\n",

-      "a=Cp/(pi*10.);##Ratio of pitch diameter of wheel A to teeth of wheel A in cm\n",

-      "b=Cp/(pi*10.);##Ratio of pitch diameter of wheel B to teeth of wheel B in cm\n",

-      "T=(2*C)/(a*10.);##Sum of teeth of wheels\n",

-      "r=NB/NA;##Ratio of teeth of wheels\n",

-      "TB=T/(r+1);##Teeth of wheel B\n",

-      "TB1=math.ceil(TB);##Teeth of wheel B\n",

-      "TA=TB1*r;##Teeth of wheel A\n",

-      "DA=a*TA;##Pitch diameter of wheel A in cm\n",

-      "DB=b*TB1;##Pitch diameter of wheel B in cm\n",

-      "CPA=(pi*DA)/TA;##Circular pitch of gear A in cm\n",

-      "CPB=(pi*DB)/TB1;##Circular pitch of gear B in cm\n",

-      "C1=(DA+DB)*10/2.;##Exact centre distance in mm\n",

-      "P=(F*1000.*pi*DA*NA)/(60.*1000.*100.);##Power transmitted in kW\n",

-      "\n",

-      "##OUTPUT\n",

-      "print'%s %.1f %s %.1f %s %.1f %s %.1f %s %.1f %s %.1f %s %.1f %s %.1f %s '%('Number of teeth on wheel A is ',TA,' '' Number of teeth on wheel B is ',TB1,' '' Pitch diameter of wheel A is ',DA,' cm'' Pitch diameter of wheel B is ',DB,' cm'' Circular pitch of wheel A is',CPA,'cm ' 'Circular pitch of wheel B is ',CPB,' cm '' Exact centre distance between shafts is ',C1,' mm'' Power transmitted is',P,' kW')\n",

-      "##================================END OF PROGRAM=============================================\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Number of teeth on wheel A is  96.0   Number of teeth on wheel B is  32.0   Pitch diameter of wheel A is  91.7  cm Pitch diameter of wheel B is  30.6  cm Circular pitch of wheel A is 3.0 cm Circular pitch of wheel B is  3.0  cm  Exact centre distance between shafts is  611.3  mm Power transmitted is 172.8  kW \n"

-       ]

-      }

-     ],

-     "prompt_number": 7

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex6-pg137"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##Chapter-4, Illustration 6, Page 137\n",

-      "##Title: Gears and Gear Drivers\n",

-      "##=============================================================================\n",

-      "import math\n",

-      "\n",

-      "##INPUT DATA\n",

-      "r=16.;##Speed ratio\n",

-      "mA=4.;##Module of gear A in mm\n",

-      "mB=mA;##Module of gear B in mm\n",

-      "mC=2.5;##Mosule of gear C in mm\n",

-      "mD=mC;##Module of gear D in mm\n",

-      "C=150.;##Distance between shafts in mm\n",

-      "\n",

-      "##CALCULATIONS\n",

-      "t=math.sqrt(r);##Ratio of teeth\n",

-      "T1=(C*2.)/mA;##Sum of teeth of wheels A and B\n",

-      "T2=(C*2.)/mC;##Sum of teeth of wheels C and D\n",

-      "TA=T1/(t+1.);##Teeth of gear A\n",

-      "TB=T1-TA;##Teeth of gear B\n",

-      "TC=T2/(t+1.);##Teeth of gear C\n",

-      "TD=T2-TC;##Teeth of gear D\n",

-      "\n",

-      "##OUTPUT\n",

-      "print'%s %.1f %s %.1f %s %.1f %s %.1f %s '%('Number of teeth on gear A is ',TA,' '' Number of teeth on gear B is ',TB,'' 'Number of teeth on gear C is ',TC,'' ' Number of teeth on gear D is ',TD,'')\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "##================================END OF PROGRAM=============================================\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Number of teeth on gear A is  15.0   Number of teeth on gear B is  60.0 Number of teeth on gear C is  24.0  Number of teeth on gear D is  96.0  \n"

-       ]

-      }

-     ],

-     "prompt_number": 8

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex7-pg138"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##Chapter-4, Illustration 7, Page 138\n",

-      "##Title: Gears and Gear Drivers\n",

-      "##=============================================================================\n",

-      "import math\n",

-      "\n",

-      "##INPUT DATA\n",

-      "N=4.5;##No. of turns\n",

-      "\n",

-      "##CALCULATIONS\n",

-      "Vh=N/2.;##Velocity ratio of main spring spindle to hour hand spindle\n",

-      "Vm=12.;##Velocity ratio of minute hand spindle to hour hand spindle\n",

-      "T1=8.##     assumed no of teeth on gear 1\n",

-      "T2=32.##    assumed no of teeth on gear 2\n",

-      "T3=(T1+T2)/4.##       no of teeth on gear 3\n",

-      "T4=(T1+T2)-T3## no of teeth on gear 4\n",

-      "print'%s %.1f %s %.1f %s %.1f %s %.1f %s '%('no of teeth on gear 1=',T1,'' 'no of teeth on gear 2=',T2,' ''no of teeth on gear 3=',T3,' ''no of teeth on gear 4=',T4,'')\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "no of teeth on gear 1= 8.0 no of teeth on gear 2= 32.0  no of teeth on gear 3= 10.0  no of teeth on gear 4= 30.0  \n"

-       ]

-      }

-     ],

-     "prompt_number": 9

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex8-pg139"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##Chapter-4, Illustration 8, Page 139\n",

-      "##Title: Gears and Gear Drivers\n",

-      "##=============================================================================\n",

-      "import math\n",

-      "\n",

-      "##Input data\n",

-      "Tb=70.;##Teeth of wheel B\n",

-      "Tc=25.;##Teeth of wheel C\n",

-      "Td=80.;##Teeth of wheel D\n",

-      "Na=-100.;##Speed of arm A in clockwise in rpm\n",

-      "y=-100.##Arm A rotates at 100 rpm clockwise\n",

-      "\n",

-      "##Calculations\n",

-      "Te=(Tc+Td-Tb);##Teeth of wheel E\n",

-      "x=(y/0.5)\n",

-      "Nc=(y-(Td*x)/Tc);##Speed of wheel C in rpm\n",

-      "\n",

-      "##Output\n",

-      "print'%s %.1f %s'%('Speed of wheel C is ',Nc,' rpm ''Direction of wheel C is anti-clockwise')\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "##================================END OF PROGRAM=============================================\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Speed of wheel C is  540.0  rpm Direction of wheel C is anti-clockwise\n"

-       ]

-      }

-     ],

-     "prompt_number": 10

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex9-pg140"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##Chapter-4, Illustration 9, Page 140\n",

-      "##Title: Gears and Gear Drivers\n",

-      "##=============================================================================\n",

-      "import math\n",

-      "\n",

-      "##Input data\n",

-      "Tb=25.;##Teeth of wheel B\n",

-      "Tc=40.;##Teeth of wheel C\n",

-      "Td=10.;##Teeth of wheel D\n",

-      "Te=25.;##Teeth of wheel E\n",

-      "Tf=30.;##Teeth of wheel F\n",

-      "y=-120.;##Speed of arm A in clockwise in rpm\n",

-      "\n",

-      "##Calculations\n",

-      "x=(-y/4.)\n",

-      "Nb=x+y;##Speed of wheel B in rpm\n",

-      "Nf=(-10/3.)*x+y;##Speed of wheel F in rpm\n",

-      "\n",

-      "##Output\n",

-      "print'%s %.1f %s %.1f %s'%('Speed of wheel B is',Nb,' rpm  Direction of wheel B is clockwise' ' Speed of wheel F is ',Nf,' rpm Direction of wheel F is clockwise')\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "##================================END OF PROGRAM=============================================\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Speed of wheel B is -90.0  rpm  Direction of wheel B is clockwise Speed of wheel F is  -220.0  rpm Direction of wheel F is clockwise\n"

-       ]

-      }

-     ],

-     "prompt_number": 12

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex10-pg141"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##Chapter-4, Illustration 10, Page 141\n",

-      "##Title: Gears and Gear Drivers\n",

-      "##=============================================================================\n",

-      "import math\n",

-      "\n",

-      "##Input data\n",

-      "Ta=96.;##Teeth of wheel A\n",

-      "Tc=48.;##Teeth of wheel C\n",

-      "y=-20.;##Speed of arm C in rpm in clockwise\n",

-      "\n",

-      "##Calculations\n",

-      "x=(y*Ta)/Tc\n",

-      "Tb=(Ta-Tc)/2.;##Teeth of wheel B\n",

-      "Nb=(-Tc/Tb)*x+y;##Speed of wheel B in rpm\n",

-      "Nc=x+y;##Speed of wheel C in rpm\n",

-      "\n",

-      "##Output\n",

-      "print'%s %.1f %s %.1f %s'%('Speed of wheel B is ',Nb,' rpm' 'Speed of wheel C is ',Nc,' rpm')\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "\n",

-      "##================================END OF PROGRAM=============================================\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Speed of wheel B is  60.0  rpmSpeed of wheel C is  -60.0  rpm\n"

-       ]

-      }

-     ],

-     "prompt_number": 13

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex11-pg142"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##Chapter-4, Illustration 11, Page 142\n",

-      "##Title: Gears and Gear Drivers\n",

-      "##=============================================================================\n",

-      "import math\n",

-      "import numpy\n",

-      "from numpy.linalg import inv\n",

-      "##Input data\n",

-      "Ta=40.##       no of teeth on gear A\n",

-      "Td=90.##       no of teeth on gear D\n",

-      "\n",

-      "##Calculations\n",

-      "Tb=(Td-Ta)/2.##      no of teeth on gear B\n",

-      "Tc=Tb##           no of teeth on gear C\n",

-      "##\n",

-      "##x+y=-1\n",

-      "##-40x+90y=45\n",

-      "\n",

-      "A=([[1, 1],[-Ta, Td]])##Coefficient matrix\n",

-      "\n",

-      "B=([[-1],[Td/2]])##Constant matrix\n",

-      "   \n",

-      "X=numpy.dot(inv(A) ,B)##Variable matrix\n",

-      "##\n",

-      "##x+y=-1\n",

-      "##-40x+90y=0\n",

-      "A1=([[1, 1],[-Ta, Td]])##Coefficient matrix\n",

-      "B1=([[-1],[0]])##Constant matrix\n",

-      "X1=numpy.dot(inv(A1) ,B1)##Variable matrix\n",

-      "b=X1[1]  \n",

-      "print(X[1]) \n",

-      "print'%s %.4f %s'%('speed of the arm =',b,' revolution clockwise')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "[ 0.03846154]\n",

-        "speed of the arm = -0.3077  revolution clockwise\n"

-       ]

-      }

-     ],

-     "prompt_number": 14

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex12-pg144"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##Chapter-4, Illustration 12, Page 144\n",

-      "##Title: Gears and Gear Drivers\n",

-      "##=============================================================================\n",

-      "\n",

-      "\n",

-      "##Input data\n",

-      "Te=30.;##Teeth of wheel E\n",

-      "Tb=24.;##Teeth of wheel B\n",

-      "Tc=22.;##Teeth of wheel C\n",

-      "Td=70.;##Teeth of wheel D\n",

-      "Th=15.;##Teeth of wheel H\n",

-      "Nv=100.;##Speed of shaft V in rpm\n",

-      "Nx=300.;##Speed of spindle X in rpm\n",

-      "\n",

-      "##Calculations\n",

-      "Nh=Nv;##Speed of wheel H in rpm\n",

-      "Ne=(-Th/Te)*Nv;##Speed of wheel E in rpm\n",

-      "Ta=(Tc+Td-Tb);##Teeth of wheel A\n",

-      "##x+y=-50\n",

-      "##y=300\n",

-      "x=(Ne-Nx)\n",

-      "Nz=(187/210.)*x+Nx;##;##Speed of wheel Z in rpm\n",

-      "\n",

-      "##Output\n",

-      "print'%s %.1f %s'%('Speed of wheel Z is ',Nz,' rpm  Direction of wheel Z is opposite to that of X')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Speed of wheel Z is  -11.7  rpm  Direction of wheel Z is opposite to that of X\n"

-       ]

-      }

-     ],

-     "prompt_number": 15

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex13-pg145"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##Chapter-4, Illustration 13, Page 145\n",

-      "##Title: Gears and Gear Drivers\n",

-      "##=============================================================================\n",

-      "\n",

-      "\n",

-      "##Input data\n",

-      "Tp=20.;##Teeth of wheel P\n",

-      "Tq=30.;##Teeth of wheel Q\n",

-      "Tr=10.;##Teeth of wheel R\n",

-      "Nx=50.;##Speed of shaft X in rpm\n",

-      "Na=100.;##Speed of arm A in rpm\n",

-      "\n",

-      "##Calculations\n",

-      "##x+y=-50\n",

-      "##y=100\n",

-      "x=(-Nx-Na)\n",

-      "y=(-2.*x+Na);##Speed of Y in rpm\n",

-      "\n",

-      "##Output\n",

-      "print'%s %.1f %s'%('Speed of driven shaft Y is ',y,' rpm  Direction of driven shaft Y is anti-clockwise')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Speed of driven shaft Y is  400.0  rpm  Direction of driven shaft Y is anti-clockwise\n"

-       ]

-      }

-     ],

-     "prompt_number": 16

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex4-pg146"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##Chapter-4, Illustration 14, Page 146\n",

-      "##Title: Gears and Gear Drivers\n",

-      "##=============================================================================\n",

-      "import math\n",

-      "\n",

-      "##Input data\n",

-      "d=216.;##Ring diameter in mm\n",

-      "m=4.;##Module in mm\n",

-      "\n",

-      "##Calculations\n",

-      "Td=(d/m);##Teeth of wheel D\n",

-      "Tb=Td/4.;##Teeth of wheel B\n",

-      "Tb1=math.ceil(Tb);##Teeth of wheel B\n",

-      "Td1=4.*Tb1;##Teeth of wheel D\n",

-      "Tc1=(Td1-Tb1)/2.;##Teeth of wheel C\n",

-      "d1=m*Td1;##Pitch circle diameter in mm\n",

-      "\n",

-      "##Output\n",

-      "print'%s %.1f %s %.1f %s %.1f %s%.1f %s '%('Teeth of wheel B is ',Tb1,' ' 'Teeth of wheel C is ',Tc1,' ' 'Teeth of wheel D is ',Td1,' '' Exact pitch circle diameter is ',d1,' mm')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Teeth of wheel B is  14.0  Teeth of wheel C is  21.0  Teeth of wheel D is  56.0   Exact pitch circle diameter is 224.0  mm \n"

-       ]

-      }

-     ],

-     "prompt_number": 17

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex15-pg147"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##Chapter-4, Illustration 15, Page 147\n",

-      "##Title: Gears and Gear Drivers\n",

-      "##=============================================================================\n",

-      "import math\n",

-      "\n",

-      "##Input data\n",

-      "Ta=100.##       no of teeth on gear A\n",

-      "Tc=101.##       no of teeth on gear C\n",

-      "Td=99.##        no of teeth on gear D\n",

-      "Tp=20.##        no of teeth on planet gear\n",

-      "y=1.##          from table 4.9(arm B makes one revolution)\n",

-      "x=-y##         as gear is fixed\n",

-      "\n",

-      "##Calculations\n",

-      "Nc=(Ta*x)/Tc+y##            Revolution of gear C \n",

-      "Nd=(Ta*x)/Td+y##            Revolution of gear D\n",

-      "\n",

-      "##Output\n",

-      "print'%s %.4f %s %.4f %s  '%('Revolution of gear C =',Nc,'' ' Revolution of gear D = ',Nd,'')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Revolution of gear C = 0.0099  Revolution of gear D =  -0.0101   \n"

-       ]

-      }

-     ],

-     "prompt_number": 18

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex16-pg148"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##Chapter-4, Illustration 16, Page 148\n",

-      "##Title: Gears and Gear Drivers\n",

-      "##=============================================================================\n",

-      "import math\n",

-      "\n",

-      "##Input data\n",

-      "Ta=12.##       no of teeth on gear A\n",

-      "Tb=60.##       no of teeth on gear B\n",

-      "N=1000.##      speed of propeller shaft in rpm\n",

-      "Nc=210.##      speed of gear C in rpm\n",

-      "\n",

-      "##Calculations\n",

-      "Nb=(Ta*N)/Tb##     speed of gear B in rpm\n",

-      "x=(Nb-Nc)\n",

-      "Nd=Nb+x##          speed of road wheel driven by D\n",

-      "\n",

-      "##Output\n",

-      "print'%s %.1f %s'%('speed of road wheel driven by D= ',Nd,' rpm')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "speed of road wheel driven by D=  190.0  rpm\n"

-       ]

-      }

-     ],

-     "prompt_number": 19

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex17-pg148"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##Chapter-4, Illustration 17, Page 148\n",

-      "##Title: Gears and Gear Drivers\n",

-      "##=============================================================================\n",

-      "import math\n",

-      "import numpy\n",

-      "from numpy.linalg import inv\n",

-      "##Input data\n",

-      "Ta=20.##   no of teeth on pinion A\n",

-      "Tb=25.##   no of teeth on wheel B\n",

-      "Tc=50.##   no of teeth on gear C\n",

-      "Td=60.##   no of teeth on gear D\n",

-      "Te=60.##  no of teeth on gear E\n",

-      "Na=200.##   SPEED of the gear A\n",

-      "Nd=100.##   speed of the gear D\n",

-      "\n",

-      "##calculations\n",

-      "##(i)\n",

-      "##(5/6)x+y=0\n",

-      "##(5/4)x+y=200\n",

-      "A1=([[Tc/Td, 1],[Tb/Ta, 1]])##Coefficient matrix\n",

-      "B1=([[0],[Na]]) ##Constant matrix\n",

-      "X1=numpy.dot(inv(A1),B1)##Variable matrix\n",

-      "Ne1=X1[1]-(Tc/Td)*X1[0]##    \n",

-      "T1=(-Ne1/Na)##     ratio of torques when D is fixed\n",

-      "##(ii)\n",

-      "##(5/4)x+y=200\n",

-      "##(5/6)x+y=100\n",

-      "A2=([[Tc/Td, 1],[Tb/Ta, 1]])##Coefficient matrix\n",

-      "B2=([[Nd],[Na]])##Constant matrix\n",

-      "X2=numpy.dot(inv(A2),B2)##Variable matrix\n",

-      "Ne2=X2[1]-(Tc/Td)*X2[0]\n",

-      "T2=(-Ne2/Na)##      ratio of torques when D ratates at 100 rpm\n",

-      "\n",

-      "##Output\n",

-      "print'%s %.2f %s %.2f %s %.2f %s %.2f %s'%('speed of E= ',Ne1,' rpm in clockwise direction' and  'speed of E in 2nd case(when D rotates at 100 rpm)= ',Ne2,' rpm in clockwise direction' and 'ratio of torques when D is fixed= ',T1,' ' 'ratio of torques when D ratates at 100 rpm= ',T2,'')\n",

-      "\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "speed of E=  -800.00 speed of E in 2nd case(when D rotates at 100 rpm)=  -300.00 ratio of torques when D is fixed=  4.00  ratio of torques when D ratates at 100 rpm=  1.50 \n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Theory_Of_Machines_by__B._K._Sarkar/Chapter6.ipynb b/_Theory_Of_Machines_by__B._K._Sarkar/Chapter6.ipynb
deleted file mode 100755
index 895e2c68..00000000
--- a/_Theory_Of_Machines_by__B._K._Sarkar/Chapter6.ipynb
+++ /dev/null
@@ -1,486 +0,0 @@
-{

- "metadata": {

-  "name": "",

-  "signature": "sha256:a0a25762305b1c74ca417d46a7390eaac10578c3f22cb04bddc542c61d85667c"

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter6-Turning Moment Diagram and Flywheel"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex1-pg175"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 6 ILLUSRTATION 1 PAGE NO 175\n",

-      "##TITLE:Turning Moment Diagram and Flywheel\n",

-      "\n",

-      "k=1.##         radius of gyration of flywheel in m\n",

-      "m=2000.##       mass of the flywheel in kg\n",

-      "T=1000.##      torque of the engine in Nm\n",

-      "w1=0.##        speedin the begining\n",

-      "t=10.##        time duration\n",

-      "##==============================\n",

-      "I=m*k**2.##         mass moment of inertia in kg-m**2\n",

-      "a=T/I##           angular acceleration of flywheel in rad/s**2\n",

-      "w2=w1+a*t##       angular speed after time t in rad/s\n",

-      "K=I*w2**2/2.##     kinetic energy of flywheel in Nm\n",

-      "##==============================\n",

-      "print'%s %.1f %s %.1f %s '%('Angular acceleration of the flywheel=',a,' rad/s**2'' Kinetic energy of flywheel= ',K,' N-m')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Angular acceleration of the flywheel= 0.5  rad/s**2 Kinetic energy of flywheel=  25000.0  N-m \n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex2-pg176"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 6 ILLUSRTATION 2 PAGE NO 176\n",

-      "##TITLE:Turning Moment Diagram and Flywheel\n",

-      "import math\n",

-      "pi=3.141\n",

-      "N1=225.##              maximum speed of flywheel in rpm\n",

-      "k=.5##                radius of gyration of flywheel in m\n",

-      "n=720.##               no of holes punched per hour\n",

-      "E1=15000.##            energy required by flywheel in Nm\n",

-      "N2=200.##              mimimum speedof flywheel in rpm\n",

-      "t=2.##                 time taking for punching a hole\n",

-      "##==========================\n",

-      "P=E1*n/3600.##              power required by motor per sec in watts\n",

-      "E2=P*t##                   energy supplied by motor to punch a hole in N-m\n",

-      "E=E1-E2##                  maximum fluctuation of energy in N-m\n",

-      "N=(N1+N2)/2.##              mean speed of the flywheel in rpm\n",

-      "m=E/(pi**2./900.*k**2.*N*(N1-N2))\n",

-      "print'%s %.1f %s %.1f %s'%('Power of the motor= ',P,' watts''Mass of the flywheel required= ',m,' kg')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Power of the motor=  3000.0  wattsMass of the flywheel required=  618.2  kg\n"

-       ]

-      }

-     ],

-     "prompt_number": 3

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex3-pg176"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 6 ILLUSRTATION 3 PAGE NO 176\n",

-      "##TITLE:Turning Moment Diagram and Flywheel\n",

-      "import math\n",

-      "pi=3.141\n",

-      "d=38.##              diameter of hole in cm\n",

-      "t=32.##              thickness of hole in cm\n",

-      "e1=7.##                energy required to punch one square mm\n",

-      "V=25.##                mean speed of the flywheel in m/s\n",

-      "S=100.##                stroke of the punch in cm\n",

-      "T=10.##                time required to punch a hole in s\n",

-      "Cs=.03##                coefficient of fluctuation of speed\n",

-      "##===================\n",

-      "A=pi*d*t##                sheared area in mm**2\n",

-      "E1=e1*A##                 energy required to punch entire area in Nm\n",

-      "P=E1/T##                 power of motor required in watts\n",

-      "T1=T/(2.*S)*t##           time required to punch a hole in 32 mm thick plate\n",

-      "E2=P*T1##               energy supplied by motor in T1 seconds\n",

-      "E=E1-E2##                maximum fluctuation of energy in Nm\n",

-      "m=E/(V**2.*Cs)##           mass of the flywheel required\n",

-      "print'%s %.1f %s'%('Mass of the flywheel required= ',m,' kg')\n",

-      "\n",

-      "\t\t"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Mass of the flywheel required=  1197.8  kg\n"

-       ]

-      }

-     ],

-     "prompt_number": 4

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex4-pg177"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 6 ILLUSRTATION 4 PAGE NO 177\n",

-      "##TITLE:Turning Moment Diagram and Flywheel\n",

-      "##figure 6.4\n",

-      "import math\n",

-      "##===================\n",

-      "pi=3.141\n",

-      "N=480.##             speed of the engine in rpm\n",

-      "k=.6##            radius of gyration in m\n",

-      "Cs=.03##           coefficient of fluctuaion of speed \n",

-      "Ts=6000.##          turning moment scale in Nm per one cm\n",

-      "C=30.##             crank angle scale in degrees per cm\n",

-      "a=[0.5,-1.22,.9,-1.38,.83,-.7,1.07]##      areas between the output torque and mean resistance line in sq.cm\n",

-      "##======================\n",

-      "w=2.*pi*N/60.##            angular speed in rad/s\n",

-      "A=Ts*C*pi/180.##            1 cm**2 of turning moment diagram in Nm\n",

-      "E1=a[0]##                max energy at B refer figure\n",

-      "E2=a[0]+a[1]+a[2]+a[3]\n",

-      "E=(E1-E2)*A##            fluctuation of energy in Nm\n",

-      "m=E/(k**2.*w**2*Cs)##        mass of the flywheel in kg\n",

-      "print'%s %.1f %s'%('Mass of the flywheel= ',m,' kg')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Mass of the flywheel=  195.8  kg\n"

-       ]

-      }

-     ],

-     "prompt_number": 5

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex5-pg178"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 6 ILLUSRTATION 5 PAGE NO 178\n",

-      "##TITLE:Turning Moment Diagram and Flywheel\n",

-      "##==============\n",

-      "pi=3.141\n",

-      "P=500.*10**3.##        power of the motor in N\n",

-      "k=.6##            radius of gyration in m\n",

-      "Cs=.03##          coefficient of fluctuation of spped \n",

-      "OA=750.##           REFER FIGURE\n",

-      "OF=6.*pi##          REFER FIGURE\n",

-      "AG=pi## REFER FIGURE\n",

-      "BG=3000.-750.## REFER FIGURE\n",

-      "GH=2.*pi## REFER FIGURE\n",

-      "CH=3000.-750.## REFER FIGURE\n",

-      "HD=pi## REFER FIGURE\n",

-      "LM=2.*pi## REFER FIGURE\n",

-      "T=OA*OF+1./2.*AG*BG+BG*GH+1./2.*CH*HD##    Torque required for one complete cycle in Nm\n",

-      "Tmean=T/(6.*pi)##                 mean torque in Nm\n",

-      "w=P/Tmean##                    angular velocity required in rad/s\n",

-      "BL=3000.-1875.## refer figure\n",

-      "KL=BL*AG/BG##   From similar trangles\n",

-      "CM=3000.-1875.## refer figure\n",

-      "MN=CM*HD/CH##from similar triangles\n",

-      "E=1./2.*KL*BL+BL*LM+1./2.*CM*MN##         Maximum fluctuaion of energy in Nm\n",

-      "m=E*100./(k**2*w**2.*Cs)##   mass of flywheel in kg\n",

-      "print'%s %.1f %s'%('Mass of the flywheel= ',m,' kg')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Mass of the flywheel=  1150.3  kg\n"

-       ]

-      }

-     ],

-     "prompt_number": 6

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex6-pg179"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 6 ILLUSRTATION 6 PAGE NO 179\n",

-      "##TITLE:Turning Moment Diagram and Flywheel\n",

-      "import math\n",

-      "pi=3.141\n",

-      "PI=180.##in degrees\n",

-      "theta1=0.\n",

-      "theta2=PI\n",

-      "m=400.##      mass of the flywheel in kg\n",

-      "N=250.##      speed in rpm\n",

-      "k=.4##       radius of gyration in m\n",

-      "n=2.*250./60000.##          no of working strokes per minute\n",

-      "W=1000.*pi-150.*math.cos((2*theta2)/57.3)-250.*math.sin((2*theta2)/57.3)-(1000.*theta1-150.*math.cos((2*theta1)/57.3)-250.*math.sin((2*theta1)/57.3))##     workdone per stroke in Nm\n",

-      "P=W*n##        power in KW\n",

-      "Tmean=W/pi##         mean torque in Nm\n",

-      "twotheta=math.atan((500/300)/57.3)##       angle at which T-Tmean becomes zero\n",

-      "THETA1=twotheta/2.\n",

-      "THETA2=(180.+twotheta)/2.\n",

-      "E=-150.*math.cos((2.*THETA2)/57.3)-250.*math.sin((2.*THETA2)/57.3)-(-150*math.cos((2.*THETA1)/57.3)-250.*math.sin((2*THETA1)/57.3))##    FLUCTUATION OF ENERGY IN Nm\n",

-      "w=2.*pi*N/60.##      angular speed in rad/s\n",

-      "Cs1=E*100./(k**2.*w**2.*m)##   fluctuation range\n",

-      "Cs=Cs1/2.##         tatal percentage of fluctuation of speed\n",

-      "Theta=60.\n",

-      "T1=300.*math.sin((2*Theta)/57.3)-500.*math.cos((2*Theta)/57.3)##        Accelerating torque in Nm(T-Tmean)\n",

-      "alpha=T1/(m*k**2.)##                              angular acceleration in rad/s**2\n",

-      "print'%s %.1f %s  %.3f %s  %.3f %s '%('Power delivered=',P,' kw''Total percentage of fluctuation speed=',Cs,' ''Angular acceleration=',alpha,'rad/s**2')\n",

-      "#in book ans is given wrong \n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Power delivered= 26.2  kwTotal percentage of fluctuation speed=  0.342  Angular acceleration=  7.965 rad/s**2 \n"

-       ]

-      }

-     ],

-     "prompt_number": 7

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex7-pg181"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 6 ILLUSRTATION 7 PAGE NO 181\n",

-      "##TITLE:Turning Moment Diagram and Flywheel\n",

-      "\n",

-      "pi=3.141\n",

-      "m=200.##      mass of the flywheel in kg\n",

-      "k=.5##       radius of gyration in m\n",

-      "N1=360.##      upper limit of speed in rpm\n",

-      "N2=240.##       lower limit of speed in rpm\n",

-      "##==========\n",

-      "I=m*k**2.##        mass moment of inertia in kg m**2\n",

-      "w1=2.*pi*N1/60.\n",

-      "w2=2.*pi*N2/60.\n",

-      "E=1./2.*I*(w1**2.-w2**2.)##    fluctuation of energy in Nm\n",

-      "Pmin=E/(4.*1000.)##       power in kw\n",

-      "Eex=Pmin*12.*1000.##  Energy expended in performing each operation in N-m\n",

-      "print'%s %.1f %s %.1f %s '%('Mimimum power required= ',Pmin,' kw' ' Energy expended in performing each operation= ',Eex,' N-m')\n",

-      "\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Mimimum power required=  4.9  kw Energy expended in performing each operation=  59195.3  N-m \n"

-       ]

-      }

-     ],

-     "prompt_number": 8

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex8-pg182"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 6 ILLUSRTATION 8 PAGE NO 182\n",

-      "##TITLE:Turning Moment Diagram and Flywheel\n",

-      "import math\n",

-      "pi=3.141\n",

-      "b=8.##    width of the strip in cm\n",

-      "t=2.##    thickness of the strip in cm\n",

-      "w=1.2*10**3.##          work required per square cm cut\n",

-      "N1=200.##                maximum speed of the flywheel in rpm\n",

-      "k=.80##                 radius of gyration in m\n",

-      "N2=(1.-.15)*N1##         minimum speed of the flywheel in rpm\n",

-      "T=3.##                   time required to punch a hole\n",

-      "##=======================\n",

-      "A=b*t##           area cut of each stroke in cm**2\n",

-      "W=w*A##            work required to cut a strip in Nm\n",

-      "w1=2.*pi*N1/60.##        speed before cut in rpm\n",

-      "w2=2.*pi*N2/60.##        speed after cut in rpm\n",

-      "m=2.*W/(k**2.*(w1**2.-w2**2.))##       mass of the flywheel required in kg\n",

-      "a=(w1-w2)/T##           angular acceleration in rad/s**2\n",

-      "Ta=m*k**2.*a##             torque required in Nm\n",

-      "print'%s %.1f %s %.1f %s '%('Mass of the flywheel= ',m,' kg'' Amount of Torque required=',Ta,'Nm')\n",

-      "\n",

-      "\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Mass of the flywheel=  493.1  kg Amount of Torque required= 330.4 Nm \n"

-       ]

-      }

-     ],

-     "prompt_number": 9

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex9-pg182"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 6 ILLUSRTATION 9 PAGE NO 182\n",

-      "##TITLE:Turning Moment Diagram and Flywheel\n",

-      "\n",

-      "pi=3.141\n",

-      "P=5.*10**3.##            power delivered by motor in watts\n",

-      "N1=360.##               speed of the flywheel in rpm\n",

-      "I=60.##                mass moment of inertia in kg m**2\n",

-      "E1=7500.##             energy required by pressing machine for 1 second in Nm\n",

-      "##========================\n",

-      "Ehr=P*60.*60.##      energy sipplied per hour in Nm\n",

-      "n=Ehr/E1\n",

-      "E=E1-P##           total fluctuation of energy in Nm\n",

-      "w1=2.*pi*N1/60.##     angular speed before pressing in rpm \n",

-      "w2=((2.*pi*N1/60.)**2.-(2.*E/I))**.5##       angular speed after pressing in rpm \n",

-      "N2=w2*60./(2.*pi)\n",

-      "R=N1-N2##              reduction in speed in rpm\n",

-      "print'%s %.1f %s %.1f %s '%('No of pressings that can be made per hour= ',n,' Reduction in speed after the pressing is over= ',R,' rpm ')\n",

-      "\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "No of pressings that can be made per hour=  2400.0  Reduction in speed after the pressing is over=  10.7  rpm  \n"

-       ]

-      }

-     ],

-     "prompt_number": 10

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex10-pg183"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 6 ILLUSRTATION 10 PAGE NO 183\n",

-      "##TITLE:Turning Moment Diagram and Flywheel\n",

-      "import math\n",

-      "pi=3.141\n",

-      "Cs=.02##     coefficient of fluctuation of speed \n",

-      "N=200.##      speed of the engine in rpm\n",

-      "\n",

-      "theta1=math.acos(0/57.3)\n",

-      "theta2=math.asin((-6000/16000)/57.3)\n",

-      "theta2=180.-theta2\n",

-      "##===============================================\n",

-      "##largest area,representing fluctuation of energy lies between theta1 and theta2\n",

-      "E=6000.*math.sin(theta2/57.3)-8000./2.*math.cos((2*theta2)/57.3)-(6000.*math.sin((theta1)/57.3)-8000./2.*math.cos((2*theta1)/57.3))##      total fluctuation of energy in Nm\n",

-      "Theta=180##    angle with which cycle will be repeated in degrees\n",

-      "Theta1=0\n",

-      "Tmean=1/pi*((15000*pi+(-8000*math.cos((2*Theta)/57.3))/2.)-((15000*Theta1+(-8000*math.cos((2*Theta1)/57.3))/2.)))##     mean torque of engine in Nm\n",

-      "P=2*pi*N*Tmean/60000.##      power of the engine in kw\n",

-      "w=2*pi*N/60.##           angular speed of the engine in rad/s\n",

-      "I=E/(w**2.*Cs)##          mass moment of inertia of flywheel in kg-m**2\n",

-      "print'%s %.1f %s %.1f %s '%('Power of the engine= ',P,' kw'' minimum mass moment of inertia of flywheel=',-I,' kg-m**2'' E value calculated in the textbook is wrong. Its value is -15,124. In textbook it is given as -1370.28')\n",

-      "\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Power of the engine=  314.1  kw minimum mass moment of inertia of flywheel= 19.5  kg-m**2 E value calculated in the textbook is wrong. Its value is -15,124. In textbook it is given as -1370.28 \n"

-       ]

-      }

-     ],

-     "prompt_number": 11

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Theory_Of_Machines_by__B._K._Sarkar/Chapter7.ipynb b/_Theory_Of_Machines_by__B._K._Sarkar/Chapter7.ipynb
deleted file mode 100755
index 064e91a6..00000000
--- a/_Theory_Of_Machines_by__B._K._Sarkar/Chapter7.ipynb
+++ /dev/null
@@ -1,638 +0,0 @@
-{

- "metadata": {

-  "name": "",

-  "signature": "sha256:e7c45b9f9a74c2d06cff538ea39937b4592b2eb0de2281e1b9530b19c7e61df9"

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter7-GOVERNORS"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex1-pg196"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 7 ILLUSRTATION 1 PAGE NO 196\n",

-      "##TITLE:GOVERNORS\n",

-      "import math\n",

-      "##===========================================================================================\n",

-      "##INPUT DATA\n",

-      "L=.4##                     LENGTH OF UPPER ARM IN m\n",

-      "THETA=30.##                 INCLINATION TO THE VERTICAL IN degrees\n",

-      "K=.02##                    RISED LENGTH IN m\n",

-      "##============================================================================================\n",

-      "h2=L*math.cos(THETA/57.3)##         GOVERNOR HEIGHT IN m\n",

-      "N2=(895./h2)**.5##           SPEED AT h2 IN rpm\n",

-      "h1=h2-K##                  LENGTH WHEN IT IS RAISED BY 2 cm\n",

-      "N1=(895./h1)**.5##           SPEED AT h1 IN rpm\n",

-      "n=(N1-N2)/N2*100.##         PERCENTAGE CHANGE IN SPEED\n",

-      "##==========================================================================================\n",

-      "print'%s %.1f %s'%('PERCENTAGE CHANGE IN SPEED=',n,' PERCENTAGE')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "PERCENTAGE CHANGE IN SPEED= 3.0  PERCENTAGE\n"

-       ]

-      }

-     ],

-     "prompt_number": 2

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex2-pg197"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 7 ILLUSRTATION 2 PAGE NO 197\n",

-      "##TITLE:GOVERNORS\n",

-      "##FIGURE 7.5(A),7.5(B)\n",

-      "import math\n",

-      "##===========================================================================================\n",

-      "##INPUT DATA\n",

-      "OA=.3##                          LENGTH OF UPPER ARM IN m\n",

-      "m=6.##                            MASS OF EACH BALL IN Kg\n",

-      "M=18.##                           MASS OF SLEEVE IN Kg\n",

-      "r2=.2##                          RADIUS OF ROTATION AT BEGINING IN m\n",

-      "r1=.25##                         RADIUS OF ROTATION AT MAX SPEED IN m\n",

-      "##===========================================================================================\n",

-      "h1=(OA**2.-r1**2.)**.5##             HIEGHT OF GOVERNOR AT MAX SPEED IN m\n",

-      "N1=(895.*(m+M)/(h1*m))**.5##      MAX SPEED IN rpm\n",

-      "h2=(OA**2.-r2**2.)**.5##             HEIGHT OF GONERNOR AT BEGINING IN m\n",

-      "N2=(895.*(m+M)/(h2*m))**.5##      MIN SPEED IN rpm\n",

-      "##===========================================================================================\n",

-      "print'%s %.1f %s %.1f %s %.1f %s'%('MAX SPEED = ',N1,' rpm'' MIN SPEED = ',N2,' rpm''RANGE OF SPEED = ',N1-N2,' rpm')\n",

-      "\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "MAX SPEED =  146.9  rpm MIN SPEED =  126.5  rpmRANGE OF SPEED =  20.4  rpm\n"

-       ]

-      }

-     ],

-     "prompt_number": 3

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex3-pg197"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 7 ILLUSRTATION 3 PAGE NO 197\n",

-      "##TITLE:GOVERNORS\n",

-      "##FIGURE 7.6\n",

-      "import math\n",

-      "##===========================================================================================\n",

-      "##INPUT DATA\n",

-      "OA=.25##                                 LENGHT OF UPPER ARM IN m\n",

-      "CD=.03##                                 DISTANCE BETWEEN LEEVE AND LOWER ARM IN m\n",

-      "m=6.##                                    MASS OF BALL IN Kg\n",

-      "M=48.##                                   MASS OF SLEEVE IN Kg\n",

-      "AE=.17##                                  FROM FIGURE 7.6\n",

-      "AE1=.12##                                 FROM FIGURE 7.6\n",

-      "r1=.2##                                  RADIUS OF ROTATION AT MAX SPEED IN m\n",

-      "r2=.15##                                 RADIUS OF ROTATION AT MIN SPEED IN m\n",

-      "##============================================================================================\n",

-      "h1=(OA**2-r1**2)**.5##                     HIEGHT OF GOVERNOR AT MIN SPEED IN m\n",

-      "TANalpha=r1/h1\n",

-      "TANbeeta=AE/(OA**2-AE**2)**.5\n",

-      "k=TANbeeta/TANalpha\n",

-      "N1=(895.*(m+(M*(1.+k)/2.))/(h1*m))**.5##    MIN SPEED IN rpm\n",

-      "h2=(OA**2-r2**2)**.5##                    HIEGHT OF GOVERNOR AT MAX SPEED IN m\n",

-      "CE=(OA**2-AE1**2)**.5\n",

-      "TANalpha1=r2/h2\n",

-      "TANbeeta1=(r2-CD)/CE\n",

-      "k=TANbeeta1/TANalpha1\n",

-      "N2=(895.*(m+(M*(1.+k)/2.))/(h2*m))**.5##    MIN SPEED IN rpm\n",

-      "##========================================================================================================\n",

-      "print'%s %.1f %s %.1f %s %.1f %s'%('MAX SPEED = ',N1,' rpm'' MIN SPEED = ',N2,' rpm''RANGE OF SPEED = ',N1-N2,' rpm')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "MAX SPEED =  215.5  rpm MIN SPEED =  188.2  rpmRANGE OF SPEED =  27.2  rpm\n"

-       ]

-      }

-     ],

-     "prompt_number": 4

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex4-pg199"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 7 ILLUSRTATION 4 PAGE NO 199\n",

-      "##TITLE:GOVERNORS\n",

-      "##FIGURE 7.7\n",

-      "import math\n",

-      "##===========================================================================================\n",

-      "##INPUT DATA\n",

-      "g=9.81##                   ACCELERATION DUE TO GRAVITY \n",

-      "OA=.20##                  LENGHT OF UPPER ARM IN m\n",

-      "AC=.20##                  LENGTH OF LOWER ARM IN m\n",

-      "CD=.025##                 DISTANCE BETWEEN AXIS AND LOWER ARM IN m\n",

-      "AB=.1##                   RADIUS OF ROTATION OF BALLS IN m\n",

-      "N2=250##                  SPEED OF THE GOVERNOR IN rpm\n",

-      "X=.05##                   SLEEVE LIFT IN m\n",

-      "m=5.##                     MASS OF BALL IN Kg\n",

-      "M=20.##                    MASS OF SLEEVE IN Kg\n",

-      "##===========================================================\n",

-      "h2=(OA**2.-AB**2.)**.5##               OB DISTANCE IN m IN FIGURE\n",

-      "h21=(AC**2.-(AB-CD)**2.)**.5##         BD DISTANCE IN m IN FIGURE\n",

-      "TANbeeta=(AB-CD)/h21##            TAN OF ANGLE OF INCLINATION OF THE LINK TO THE VERTICAL\n",

-      "TANalpha=AB/h2##                  TAN OF ANGLE OF INCLINATION OF THE ARM TO THE VERTICAL\n",

-      "k=TANbeeta/TANalpha\n",

-      "c=X/(2.*(h2*(1.+k)-X))##            PERCENTAGE INCREASE IN SPEED \n",

-      "n=c*N2##                          INCREASE IN SPEED IN rpm\n",

-      "N1=N2+n##                          SPEED AFTER LIFT OF SLEEVE\n",

-      "E=c*g*((2.*m/(1.+k))+M)##            GOVERNOR EFFORT IN N\n",

-      "P=E*X##                            GOVERNOR POWER IN N-m\n",

-      "\n",

-      "print'%s %.1f %s  %.2f %s  %.1f %s '%('SPEED OF THE GOVERNOR WHEN SLEEVE IS LIFT BY 5 cm = ',N1,' rpm'' GOVERNOR EFFORT = ',E,' N' 'GOVERNOR POWER = ',P,' N-m')\n",

-      "\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "SPEED OF THE GOVERNOR WHEN SLEEVE IS LIFT BY 5 cm =  275.6  rpm GOVERNOR EFFORT =   25.95  NGOVERNOR POWER =   1.3  N-m \n"

-       ]

-      }

-     ],

-     "prompt_number": 5

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex5-pg200"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 7 ILLUSRTATION 5 PAGE NO 200\n",

-      "##TITLE:GOVERNORS\n",

-      "##FIGURE 7.8\n",

-      "import math\n",

-      "##===========================================================================================\n",

-      "##INPUT DATA\n",

-      "g=9.81##                   ACCELERATION DUE TO GRAVITY \n",

-      "OA=.30##                  LENGHT OF UPPER ARM IN m\n",

-      "AC=.30##                  LENGTH OF LOWER ARM IN m\n",

-      "m=10.##                     MASS OF BALL IN Kg\n",

-      "M=50.##                    MASS OF SLEEVE IN Kg\n",

-      "r=.2##                    RADIUS OF ROTATION IN m\n",

-      "CD=.04##                  DISTANCE BETWEEN AXIS AND LOWER ARM IN m\n",

-      "F=15.##                    FRICTIONAL LOAD ACTING IN N\n",

-      "##============================================================\n",

-      "h=(OA**2-r**2)**.5##           HIEGTH OF THE GOVERNOR IN m\n",

-      "AE=r-CD##                   AE VALUE IN m\n",

-      "CE=(AC**2-AE**2)**.5##         BD DISTANCE IN m\n",

-      "TANalpha=r/h##              TAN OF ANGLE OF INCLINATION OF THE ARM TO THE VERTICAL\n",

-      "TANbeeta=AE/CE##            TAN OF ANGLE OF INCLINATION OF THE LINK TO THE VERTICAL\n",

-      "k=TANbeeta/TANalpha\n",

-      "N=((895./h)*(m+(M*(1.+k)/2.))/m)**.5##      EQULIBRIUM SPEED IN rpm\n",

-      "N1=((895./h)*((m*g)+(M*g+F)/2.)*(1.+k)/(m*g))**.5##        MAX SPEED IN rpm\n",

-      "N2=((895./h)*((m*g)+(M*g-F)/2.)*(1.+k)/(m*g))**.5##        MIN SPEED IN rpm\n",

-      "R=N1-N2##                                   RANGE OF SPEED\n",

-      "print'%s %.1f %s %.1f %s '%('EQUILIBRIUM SPEED OF GOVERNOR = ',N,' rpm'' RANGE OF SPEED OF GOVERNOR= ',R,' rpm')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "EQUILIBRIUM SPEED OF GOVERNOR =  145.1  rpm RANGE OF SPEED OF GOVERNOR=  3.4  rpm \n"

-       ]

-      }

-     ],

-     "prompt_number": 6

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex6-pg202"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 7 ILLUSRTATION 6 PAGE NO 202\n",

-      "##TITLE:GOVERNORS\n",

-      "##FIGURE 7.9\n",

-      "import math\n",

-      "##===========================================================================================\n",

-      "##INPUT DATA\n",

-      "g=9.81##                   ACCELERATION DUE TO GRAVITY \n",

-      "OA=.30##                  LENGHT OF UPPER ARM IN m\n",

-      "AC=.30##                  LENGTH OF LOWER ARM IN m\n",

-      "m=5.##                     MASS OF BALL IN Kg\n",

-      "M=25.##                    MASS OF SLEEVE IN Kg\n",

-      "X=.05##                   LIFT OF THE SLEEVE\n",

-      "alpha=30.##                ANGLE OF INCLINATION OF THE ARM TO THE VERTICAL\n",

-      "##==============================================\n",

-      "h2=OA*math.cos(alpha/57.3)##        HEIGHT OF THE GOVERNOR AT LOWEST POSITION OF SLEEVE\n",

-      "h1=h2-X/2.##                HEIGHT OF THE GOVERNOR AT HEIGHT POSITION OF SLEEVE\n",

-      "F=((h2/h1)*(m*g+M*g)-(m*g+M*g))/(1.+h2/h1)##      FRICTION AT SLEEVE IN N\n",

-      "N1=((m*g+M*g+F)*895./(h1*m*g))**.5##          MAX SPEEED OF THE GOVVERNOR IN rpm\n",

-      "N2=((m*g+M*g-F)*895./(h2*m*g))**.5##          MIN SPEEED OF THE GOVVERNOR IN rpm\n",

-      "R=N1-N2##                                   RANGE OF SPEED IN rpm\n",

-      "\n",

-      "print'%s %.1f %s %.1f %s'%('THE VALUE OF FRICTIONAL FORCE= ',F,' F'' RANGE OF SPEED OF THE GOVERNOR = ',R,' rpm')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "THE VALUE OF FRICTIONAL FORCE=  14.9  F RANGE OF SPEED OF THE GOVERNOR =  14.9  rpm\n"

-       ]

-      }

-     ],

-     "prompt_number": 7

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex7-pg203"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 7 ILLUSRTATION 7 PAGE NO 203\n",

-      "##TITLE:GOVERNORS\n",

-      "import math\n",

-      "##===========================================================================================\n",

-      "##INPUT DATA\n",

-      "PI=3.147\n",

-      "m=3##                 MASS OF EACH BALL IN Kg\n",

-      "a=.12##               LENGTH OF VERTICAL ARM OF BELL CRANK LEVER IN m\n",

-      "b=.08##               LENGTH OF HORIZONTAL ARM OF BELL CRANK LEVER IN m\n",

-      "r2=.12##              RADIUS OF ROTATION OF THE BALL FOR LOWEST POSITION IN m\n",

-      "N2=320.##               SPEED OF GOVERNOR AT THE BEGINING IN rpm\n",

-      "S=20000.##                 STIFFNESS OF THE SPRING IN N/m\n",

-      "h=.015##                  SLEEVE LIFT IN m\n",

-      "##==================================================\n",

-      "Fc2=m*(2.*PI*N2/60.)**2*r2##               CENTRIFUGAL FORCE ACTING AT MIN SPEED OF ROTATION IN N\n",

-      "L=2*a*Fc2/b##                           INITIAL LOAD ON SPRING IN N\n",

-      "r1=a/b*h+r2##                           MAX RADIUS OF ROTATION IN m\n",

-      "Fc1=(S*(r1-r2)*(b/a)**2/2)+Fc2##         CENTRIFUGAL FORCE ACTING AT MAX SPEED OF ROTATION IN N\n",

-      "N1=(Fc1/(m*r1)*(60./2./PI)**2)**.5\n",

-      "print'%s %.1f %s %.1f %s '%('INITIAL LOAD ON SPRING =',L,' N'' EQUILIBRIUM SPEED CORRESPONDING TO LIFT OF 15 cm =',N1,' rpm')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "INITIAL LOAD ON SPRING = 1217.0  N EQUILIBRIUM SPEED CORRESPONDING TO LIFT OF 15 cm = 327.9  rpm \n"

-       ]

-      }

-     ],

-     "prompt_number": 8

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex7-pg204"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 7 ILLUSRTATION 8 PAGE NO 204\n",

-      "##TITLE:GOVERNORS\n",

-      "\n",

-      "##===========================================================================================\n",

-      "##INPUT DATA\n",

-      "PI=3.147\n",

-      "m=3##                           MASS OF BALL IN Kg\n",

-      "r2=.2##                         INITIAL RADIUS OF ROTATION IN m\n",

-      "a=.11##               LENGTH OF VERTICAL ARM OF BELL CRANK LEVER IN m\n",

-      "b=.15##               LENGTH OF HORIZONTAL ARM OF BELL CRANK LEVER IN m\n",

-      "h=.004##                  SLEEVE LIFT IN m\n",

-      "N2=240.##                INITIAL SPEED IN rpm\n",

-      "n=7.5##                    FLUCTUATION OF SPEED IN %\n",

-      "##===================================\n",

-      "w2=2.*PI*N2/60.##                  INITIAL ANGULAR SPEED IN rad/s\n",

-      "w1=(100.+n)*w2/100.##              FINAL ANGULAR SPEED IN rad/s\n",

-      "F=2.*a/b*m*w2**2.*r2##              INITIAL COMPRESSIVE FORCE IN N\n",

-      "r1=r2+a/b*h##                    MAX RDIUS OF ROTATION IN m\n",

-      "S=2.*((m*w1**2.*r1)-(m*w2**2.*r2))/(r1-r2)*(a/b)**2.\n",

-      "print'%s %.1f %s %.1f %s'%('INITIAL COMPRESSIVE FPRCE = ',F,' N'' STIFFNESS OF THE SPRING = ',S/1000,' N/m')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "INITIAL COMPRESSIVE FPRCE =  557.8  N STIFFNESS OF THE SPRING =  24.1  N/m\n"

-       ]

-      }

-     ],

-     "prompt_number": 9

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex9-pg204"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 7 ILLUSRTATION 9 PAGE NO 204\n",

-      "##TITLE:GOVERNORS\n",

-      "##FIGURE 7.3(C)\n",

-      "\n",

-      "##===========================================================================================\n",

-      "##INPUT DATA\n",

-      "g=9.81##                   ACCELERATION DUE TO GRAVITY \n",

-      "PI=3.147\n",

-      "r=.14##                          DISTANCE BETWEEN THE CENTRE OF PIVOT OF BELL CRANK LEVER AND AXIS OF GOVERNOR SPINDLE IN m\n",

-      "r2=.11##                         INITIAL RADIUS OF ROTATION IN m\n",

-      "a=.12##                          LENGTH OF VERTICAL ARM OF BELL CRANK LEVER IN m\n",

-      "b=.10##                          LENGTH OF HORIZONTAL ARM OF BELL CRANK LEVER IN m\n",

-      "h=.05##                         SLEEVE LIFT IN m\n",

-      "N2=240##                         INITIAL SPEED IN rpm\n",

-      "F=30##                           FRICTIONAL FORCE ACTING IN N\n",

-      "m=5##                            MASS OF EACH BALL IN Kg\n",

-      "##==========================================\n",

-      "r1=r2+a/b*h##                    MAX RADIUS OF ROTATION IN m\n",

-      "N1=41.*N2/39.##                 MAX SPEED OF ROTATION IN rpm\n",

-      "N=(N1+N2)/2.##                 MEAN SPEED IN rpm\n",

-      "Fc1=m*(2.*PI*N1/60.)**2.*r1##     CENTRIFUGAL FORCE ACTING AT MAX SPEED OF ROTATION IN N\n",

-      "Fc2=m*(2.*PI*N2/60.)**2.*r2##     CENTRIFUGAL FORCE ACTING AT MIN SPEED OF ROTATION IN N\n",

-      "c1=r1-r##                     FROM FIGURE 7.3(C) IN m\n",

-      "a1=(a**2.-c1**2.)**.5##            FROM FIGURE 7.3(C) IN m\n",

-      "b1=(b**2.-(h/2.)**2.)**.5##             FROM FIGURE 7.3(C) IN m\n",

-      "c2=r-r2##                     FROM FIGURE 7.3(C) IN m\n",

-      "a2=a1##                       FROM FIGURE 7.3(C) IN m\n",

-      "b2=b1##                       FROM FIGURE 7.3(C) IN m\n",

-      "S1=2.*((Fc1*a1)-(m*g*c1))/b1##          SPRING FORCE EXERTED ON THE SLEEVE AT MAXIMUM SPEED IN NEWTONS\n",

-      "S2=2.*((Fc2*a2)-(m*g*c2))/b2##          SPRING FORCE EXERTED ON THE SLEEVE AT MAXIMUM SPEED IN NEWTONS\n",

-      "S=(S1-S2)/h##                   STIFFNESS OF THE SPRING IN N/m\n",

-      "Is=S2/S##                       INITIAL COMPRESSION OF SPRING IN m\n",

-      "P=S2+(h/2.*S)##                  SPRING FORCE OF MID PORTION IN N\n",

-      "n1=N*((P+F)/P)**.5##             SPEED,WHEN THE SLEEVE BEGINS TO MOVE UPWARDS FROM MID POSITION IN rpm\n",

-      "n2=N*((P-F)/P)**.5##             SPEED,WHEN THE SLEEVE BEGINS TO MOVE DOWNWARDS FROM MID POSITION IN rpm\n",

-      "A=n1-n2##                        ALTERATION IN SPEED IN rpm\n",

-      "print'%s %.1f %s %.1f %s '%('INTIAL COMPRESSION OF SPRING= ',Is*100,' cm''ALTERATION IN SPEED = ',A,' rpm')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "INTIAL COMPRESSION OF SPRING=  6.8  cmALTERATION IN SPEED =  6.7  rpm \n"

-       ]

-      }

-     ],

-     "prompt_number": 10

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex10-pg206"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 7 ILLUSRTATION 10 PAGE NO 206\n",

-      "##TITLE:GOVERNORS\n",

-      "##FIGURE 7.10\n",

-      "import math\n",

-      "##===========================================================================================\n",

-      "##INPUT DATA\n",

-      "PI=3.147\n",

-      "AE=.25##                  LENGTH OF UPPER ARM IN m\n",

-      "CE=.25##                  LENGTH OF LOWER ARM IN m\n",

-      "EH=.1##                   LENGTH OF EXTENDED ARM IN m\n",

-      "EF=.15##                  RADIUS OF BALL PATH IN m\n",

-      "m=5.##                     MASS OF EACH BALL IN Kg\n",

-      "M=40.##                    MASS OF EACH BALL IN Kg\n",

-      "##===================================================================\n",

-      "h=(AE**2.-EF**2.)**.5##           HEIGHT OF THE GOVERNOR IN m\n",

-      "EM=h\n",

-      "HM=EH+EM##                   FROM FIGURE 7.10\n",

-      "N=((895./h)*(EM/HM)*((m+M)/m))**.5\n",

-      "print'%s %.1f %s'%('EQUILIBRIUM SPEED OF GOVERNOR =',N,' rpm')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "EQUILIBRIUM SPEED OF GOVERNOR = 163.9  rpm\n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex11-pg207"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 7 ILLUSRTATION 11 PAGE NO 207\n",

-      "##TITLE:GOVERNORS\n",

-      "##FIGURE 7.11\n",

-      "import math\n",

-      "##===========================================================================================\n",

-      "##INPUT DATA\n",

-      "PI=3.147\n",

-      "g=9.81##                  ACCELERATION DUE TO GRAVITY IN N/mm**2\n",

-      "AE=.25##                  LENGTH OF UPPER ARM IN m\n",

-      "CE=.25##                  LENGTH OF LOWER ARM IN m\n",

-      "ER=.175##                 FROM FIGURE 7.11\n",

-      "AP=.025##                 FROM FIGURE 7.11\n",

-      "FR=AP##                   FROM FIGURE 7.11\n",

-      "CQ=FR##                   FROM FIGURE 7.11\n",

-      "m=3.2##                     MASS OF BALL IN Kg\n",

-      "M=25.##                    MASS OF SLEEVE IN Kg\n",

-      "h=.2##                    VERTICAL HEIGHT OF GOVERNOR IN m\n",

-      "EM=h##                    FROM FIGURE 7.11\n",

-      "AF=h##                    FROM FIGURE 7.11\n",

-      "N=160.##                   SPEED OF THE GOVERNOR IN rpm\n",

-      "HM=(895.*EM*(m+M)/(h*N**2.*m))\n",

-      "x=HM-EM##                LENGTH OF EXTENDED LINK IN m\n",

-      "T1=g*(m+M/2.)*AE/AF##     TENSION IN UPPER ARM IN N\n",

-      "print'%s %.3f %s %.1f %s'%('LENGTH OF EXTENDED LINK = ',x,' m''TENSION IN UPPER ARM =',T1,' N')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "LENGTH OF EXTENDED LINK =  0.108  mTENSION IN UPPER ARM = 192.5  N\n"

-       ]

-      }

-     ],

-     "prompt_number": 2

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex12-pg208"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 7 ILLUSRTATION 12 PAGE NO 208\n",

-      "##TITLE:GOVERNORS\n",

-      "##FIGURE 7.12,7.13\n",

-      "import math\n",

-      "##===========================================================================================\n",

-      "##INPUT DATA\n",

-      "PI=3.147\n",

-      "EF=.20##               MINIMUM RADIUS OF ROTATION IN m\n",

-      "AE=.30##               LENGTH OF EACH ARM IN m\n",

-      "A1E1=AE##              COMPARING FIRUES 7.12&7.13\n",

-      "EC=.30##               LENGTH OF EACH ARM IN m\n",

-      "E1C1=EC##              LENGTH OF EACH ARM IN m\n",

-      "ED=.165##              FROM FIGURE 7.12 IN m\n",

-      "MC=ED##                FROM FIGURE 7.12\n",

-      "EH=.10##                FROM FIGURE 7.12 IN m\n",

-      "m=8.##                  MASS OF BALL IN Kg \n",

-      "M=60.##                 MASS OF SLEEVE IN Kg\n",

-      "DF=.035##              SLEEVE DISTANCE FROM AXIS IN m\n",

-      "E1F1=.25##             MAX RADIUS OF ROTATION IN m\n",

-      "g=9.81\n",

-      "##=========================================================\n",

-      "alpha=math.asin((EF/AE))*57.3##     ANGLE OF INCLINATION OF THE ARM TO THE VERTICAL IN DEGREES\n",

-      "beeta=math.asin((ED/EC))*57.3##     ANGLE OF INCLINATION OF THE ARM TO THE HORIZONTAL IN DEGREES\n",

-      "k=math.tan(beeta/57.3)/math.tan(alpha/57.3)\n",

-      "h=(AE**2.-EF**2.)**.5##        HEIGHT OF GOVERNOR IN m\n",

-      "EM=(EC**2.-MC**2.)**.5##       FROM FIGURE 7.12 IN m\n",

-      "HM=EM+EH\n",

-      "N2=(895.*EM*(m+(M/2.*(1.+k)))/(h*HM*m))**.5##      EQUILIBRIUM SPEED AT MAX RADIUS\n",

-      "HC=(HM**2.+MC**2.)**.5##                      FROM FIGURE 7.13 IN m\n",

-      "H1C1=HC\n",

-      "gama=math.atan((MC/HM))*57.3\n",

-      "alpha1=math.asin((E1F1/A1E1))*57.3\n",

-      "E1D1=E1F1-DF##                             FROM FIGURE 7.13 IN m\n",

-      "beeta1=math.asin((E1D1/E1C1))*57.3\n",

-      "gama1=gama-beeta+beeta1\n",

-      "r=H1C1*math.sin(gama1/57.3)+DF##                      RADIUS OF ROTATION IN m\n",

-      "H1M1=H1C1*math.cos((gama1/57.3))\n",

-      "I1C1=E1C1*math.cos(beeta1/57.3)*(math.tan(alpha1/57.3)+math.tan(beeta1/57.3))## FROM FIGURE IN m\n",

-      "M1C1=H1C1*math.sin(gama1/57.3)\n",

-      "w1=(((m*g*(I1C1-M1C1))+(M*g*I1C1)/2.)/(m*r*H1M1))**.5##   ANGULAR SPEED IN rad/s\n",

-      "N1=w1*60./(2.*PI)##                         ##SPEED IN m/s\n",

-      "print'%s %.1f %s %.1f %s '%('MINIMUM SPEED OF ROTATION =',N2,' rpm'' MAXIMUM SPEED OF ROTATION = ',N1,' rpm')\n",

-      "\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "MINIMUM SPEED OF ROTATION = 146.6  rpm MAXIMUM SPEED OF ROTATION =  156.3  rpm \n"

-       ]

-      }

-     ],

-     "prompt_number": 3

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Theory_Of_Machines_by__B._K._Sarkar/Chapter8.ipynb b/_Theory_Of_Machines_by__B._K._Sarkar/Chapter8.ipynb
deleted file mode 100755
index 9bd9a862..00000000
--- a/_Theory_Of_Machines_by__B._K._Sarkar/Chapter8.ipynb
+++ /dev/null
@@ -1,334 +0,0 @@
-{

- "metadata": {

-  "name": "",

-  "signature": "sha256:1cb0ae5332b03066df5ce763bd8fad0da93c877f86bbb84639588cca0d91016e"

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Chapter8-BALANCING OF ROTATING MASSES"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex1-pg221"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 8 ILLUSRTATION 1 PAGE NO 221\n",

-      "##TITLE:BALANCING OF ROTATING MASSES\n",

-      "pi=3.141\n",

-      "import math\n",

-      "mA=12.##       mass of A in kg\n",

-      "mB=10.##       mass of B in kg\n",

-      "mC=18.##       mass of C in kg\n",

-      "mD=15.##       mass of D in kg\n",

-      "rA=40.##       radius of A in mm\n",

-      "rB=50.##       radius of B in mm\n",

-      "rC=60.##       radius of C in mm\n",

-      "rD=30.##       radius of D in mm\n",

-      "theta1=0.##    angle between A-A in degrees\n",

-      "theta2=60.##   angle between A-B in degrees\n",

-      "theta3=130.##  angle between A-C in degrees\n",

-      "theta4=270.##  angle between A-D in degrees\n",

-      "R=100.##  radius at which mass to be determined in mm\n",

-      "##====================================================\n",

-      "Fh=(mA*rA*math.cos(theta1/57.3)+mB*rB*math.cos(theta2/57.3)+mC*rC*math.cos(theta3/57.3)+mD*rD*math.cos(theta4/57.3))/10.##    vertical component value in kg cm\n",

-      "Fv=(mA*rA*math.sin(theta1/57.3)+mB*rB*math.sin(theta2/57.3)+mC*rC*math.sin(theta3/57.3)+mD*rD*math.sin(theta4/57.3))/10.##   horizontal component value in kg cm\n",

-      "mb=(Fh**2.+Fv**2.)**.5/R*10.##     unbalanced mass in kg\n",

-      "theta=math.atan(Fv/Fh)*57.3##   position in degrees \n",

-      "THETA=180.+theta##       angle with mA\n",

-      "print'%s %.1f %s %.1f %s'%('magnitude of unbalaced mass=',mb,' kg'' angle with mA=',THETA,'degrees')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "magnitude of unbalaced mass= 8.1  kg angle with mA= 267.5 degrees\n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex2-pg222"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 8 ILLUSRTATION 2 PAGE NO 222\n",

-      "##TITLE:BALANCING OF ROTATING MASSES\n",

-      "pi=3.141\n",

-      "\n",

-      "mA=5.##   mass of A in kg\n",

-      "mB=10.##   mass of B in kg\n",

-      "mC=8.##     mass of C in kg\n",

-      "rA=10.##   radius of A in cm\n",

-      "rB=15.##   radius of B in cm\n",

-      "rC=10.##    radius of C in cm\n",

-      "rD=10.##   radius of D in cm\n",

-      "rE=15.##   radius of E in cm\n",

-      "##============================\n",

-      "mD=182./rD##    mass of D in kg by mearument\n",

-      "mE=80./rE##     mass of E in kg  by mearument\n",

-      "print'%s %.1f %s %.1f %s '%('mass of D= ',mD,' kg''mass of E= ',mE,' kg')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "mass of D=  18.2  kgmass of E=  5.3  kg \n"

-       ]

-      }

-     ],

-     "prompt_number": 2

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex3-pg223"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 8 ILLUSRTATION 3 PAGE NO 223\n",

-      "##TITLE:BALANCING OF ROTATING MASSES\n",

-      "pi=3.141\n",

-      "\n",

-      "mA=200.##       mass of A in kg\n",

-      "mB=300.##       mass of B in kg\n",

-      "mC=400.##       mass of C in kg\n",

-      "mD=200.##       mass of D in kg\n",

-      "rA=80.##       radius of A in mm\n",

-      "rB=70.##       radius of B in mm\n",

-      "rC=60.##       radius of C in mm\n",

-      "rD=80.##       radius of D in mm\n",

-      "rX=100.##      radius of X in mm\n",

-      "rY=100.##     radius of Y in mm\n",

-      "##=====================\n",

-      "mY=7.3/.04##    mass of Y in kg by mearurement\n",

-      "mX=35./.1##      mass of X in kg by mearurement\n",

-      "thetaX=146.##   in degrees by mesurement\n",

-      "print'%s %.1f %s %.1f %s %.1f %s'%('mass of X=',mX,' kg'' mass of Y=',mY,' kg''angle with mA=',thetaX,' degrees')\n",

-      "\t"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "mass of X= 350.0  kg mass of Y= 182.5  kgangle with mA= 146.0  degrees\n"

-       ]

-      }

-     ],

-     "prompt_number": 3

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex4-pg225"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 8 ILLUSRTATION 4 PAGE NO 225\n",

-      "##TITLE:BALANCING OF ROTATING MASSES\n",

-      "pi=3.141\n",

-      "\n",

-      "mB=30##       mass of B in kg\n",

-      "mC=50##       mass of C in kg\n",

-      "mD=40##       mass of D in kg\n",

-      "rA=18##       radius of A in cm\n",

-      "rB=24##       radius of B in cm\n",

-      "rC=12##       radius of C in cm\n",

-      "rD=15##       radius of D in cm\n",

-      "##=============================\n",

-      "mA=3.6/.18##         mass of A by measurement in kg\n",

-      "theta=124.##          angle with mass B in degrees by measurement in degrees\n",

-      "y=3.6/(.18*20)##     position of A from B\n",

-      "print'%s %.1f %s %.1f %s %.1f %s'%('mass of A=',mA,' kg'' angle with mass B=',theta,' degrees'' position of A from B=',y,' m towards right of plane B')"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "mass of A= 20.0  kg angle with mass B= 124.0  degrees position of A from B= 1.0  m towards right of plane B\n"

-       ]

-      }

-     ],

-     "prompt_number": 4

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex5-pg226"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 8 ILLUSRTATION 5 PAGE NO 226\n",

-      "##TITLE:BALANCING OF ROTATING MASSES\n",

-      "pi=3.141\n",

-      "\n",

-      "mB=10.##       mass of B in kg\n",

-      "mC=5.##       mass of C in kg\n",

-      "mD=4.##       mass of D in kg\n",

-      "rA=10.##       radius of A in cm\n",

-      "rB=12.5##       radius of B in cm\n",

-      "rC=20.##       radius of C in cm\n",

-      "rD=15.##       radius of D in cm\n",

-      "##=====================================\n",

-      "mA=7.##      mass of A in kg by mesurement\n",

-      "BC=118.##     angle between B and C in degrees by mesurement\n",

-      "BA=203.5##   angle between B and A in degrees by mesurement\n",

-      "BD=260.##     angle between B and D in degrees by mesurement\n",

-      "print'%s %.1f %s %.1f %s %.1f %s %.1f %s '%('Mass of A=',mA,' kg'' angle between B and C=',BC,' degrees''angle between B and A= ',BA,' degrees'' angle between B and D=',BD,' degrees')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Mass of A= 7.0  kg angle between B and C= 118.0  degreesangle between B and A=  203.5  degrees angle between B and D= 260.0  degrees \n"

-       ]

-      }

-     ],

-     "prompt_number": 5

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex6-pg228"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 8 ILLUSRTATION 6 PAGE NO 228\n",

-      "##TITLE:BALANCING OF ROTATING MASSES\n",

-      "pi=3.141\n",

-      "\n",

-      "mB=36.##       mass of B in kg\n",

-      "mC=25.##       mass of C in kg\n",

-      "rA=20.##       radius of A in cm\n",

-      "rB=15.##       radius of B in cm\n",

-      "rC=15.##       radius of C in cm\n",

-      "rD=20.##       radius of D in cm\n",

-      "##==================================\n",

-      "mA=3.9/.2##       mass of A in kg by measurement\n",

-      "mD=16.5##        mass of D in kg by measurement\n",

-      "theta=252.##      angular position of D from B by measurement in degrees\n",

-      "print'%s %.1f %s %.1f %s %.1f %s'%('Mass of A= ',mA,' kg'' Mass od D= ',mD,' kg''  Angular position of D from B= ',theta,' degrees')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Mass of A=  19.5  kg Mass od D=  16.5  kg  Angular position of D from B=  252.0  degrees\n"

-       ]

-      }

-     ],

-     "prompt_number": 6

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex7-pg229"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 8 ILLUSRTATION 7 PAGE NO 229\n",

-      "##TITLE:BALANCING OF ROTATING MASSES\n",

-      "\n",

-      "\n",

-      "pi=3.141\n",

-      "mA=48.##     mass of A in kg\n",

-      "mB=56.##       mass of B in kg\n",

-      "mC=20.##       mass of C in kg\n",

-      "rA=1.5##       radius of A in cm\n",

-      "rB=1.5##       radius of B in cm\n",

-      "rC=1.25##       radius of C in cm\n",

-      "N=300.##   speed in rpm\n",

-      "d=1.8##   distance between bearing in cm\n",

-      "##================================\n",

-      "w=2.*pi*N/60.##        angular speed in rad/s\n",

-      "BA=164.##    angle between pulleys B&A in degrees by measurement\n",

-      "BC=129.##    angle between pulleys B&C in degrees by measurement\n",

-      "AC=67.##     angle between pulleys A&C in degrees by measurement\n",

-      "C=.88*w**2.##    out of balance couple in N\n",

-      "L=C/d##    load on each bearing in N\n",

-      "print'%s %.1f %s  %.1f %s  %.1f %s  %.1f %s  %.1f %s '%('angle between pulleys B&A=',BA,' degrees'' angle between pulleys B&C= ',BC,' degrees'' angle between pulleys A&C=',AC,' degrees'' out of balance couple= ',C,' N'' load on each bearing=',L,' N')"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "angle between pulleys B&A= 164.0  degrees angle between pulleys B&C=   129.0  degrees angle between pulleys A&C=  67.0  degrees out of balance couple=   868.2  N load on each bearing=  482.3  N \n"

-       ]

-      }

-     ],

-     "prompt_number": 7

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/_Theory_Of_Machines_by__B._K._Sarkar/Chapter9.ipynb b/_Theory_Of_Machines_by__B._K._Sarkar/Chapter9.ipynb
deleted file mode 100755
index 0fbeb89f..00000000
--- a/_Theory_Of_Machines_by__B._K._Sarkar/Chapter9.ipynb
+++ /dev/null
@@ -1,151 +0,0 @@
-{

- "metadata": {

-  "name": "",

-  "signature": "sha256:dda7459eb606339995d5ed2e2c12f6be43bc2a1b7dc283fd0394011879a85b71"

- },

- "nbformat": 3,

- "nbformat_minor": 0,

- "worksheets": [

-  {

-   "cells": [

-    {

-     "cell_type": "heading",

-     "level": 1,

-     "metadata": {},

-     "source": [

-      "Chapter9-CAMS AND FOLLOWERS"

-     ]

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex2-pg247"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 9 ILLUSRTATION 2 PAGE NO 247\n",

-      "##TITLE:CAMS AND FOLLOWERS\n",

-      "import math\n",

-      "pi=3.141\n",

-      "s=4.##         follower movement in cm\n",

-      "theta=60.##    cam rotation in degrees\n",

-      "THETA=60.*pi/180##   cam rotation in rad\n",

-      "thetaD=45.##    after outstroke in degrees\n",

-      "thetaR=90.##....angle with which it reaches its original position in degrees\n",

-      "THETAR=90.*pi/180##   angle with which it reaches its original position in rad\n",

-      "THETAd=360.-theta-thetaD-thetaR##      angle after return stroke in degrees\n",

-      "N=300.##   speed in rpm\n",

-      "w=2.*pi*N/60.##   speed in rad/s\n",

-      "Vo=pi*w*s/2./THETA##   Maximum velocity of follower during outstroke in cm/s\n",

-      "Vr=pi*w*s/2./THETAR## Maximum velocity of follower during return stroke in cm/s\n",

-      "Fo=pi**2.*w**2.*s/2./THETA**2./100.##Maximum acceleration of follower during outstroke in m/s**2 \n",

-      "Fr=pi**2.*w**2.*s/2./THETAR**2/100.##Maximum acceleration of follower during return stroke in m/s**2\n",

-      "print'%s %.1f %s %.1f %s '%('Maximum acceleration of follower during outstroke =',Fo,' m/s**2''Maximum acceleration of follower during return stroke= ',Fr,' m/s**2')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Maximum acceleration of follower during outstroke = 177.6  m/s**2Maximum acceleration of follower during return stroke=  78.9  m/s**2 \n"

-       ]

-      }

-     ],

-     "prompt_number": 3

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex3-pg249"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 9 ILLUSRTATION 3 PAGE NO 249\n",

-      "##TITLE:CAMS AND FOLLOWERS\n",

-      "import math\n",

-      "pi=3.141\n",

-      "s=5.##         follower movement in cm\n",

-      "theta=120.##    cam rotation in degrees\n",

-      "THETA=theta*pi/180.##   cam rotation in rad\n",

-      "thetaD=30.##    after outstroke in degrees\n",

-      "thetaR=60.##....angle with which it reaches its original position in degrees\n",

-      "THETAR=60.*pi/180.##   angle with which it reaches its original position in rad\n",

-      "THETAd=360.-theta-thetaD-thetaR##      angle after return stroke in degrees\n",

-      "N=100.##   speed in rpm\n",

-      "w=2.*pi*N/60.##   speed in rad/s\n",

-      "Vo=pi*w*s/2./THETA##   Maximum velocity of follower during outstroke in cm/s\n",

-      "Vr=pi*w*s/2./THETAR## Maximum velocity of follower during return stroke in cm/s\n",

-      "Fo=pi**2.*w**2.*s/2./THETA**2./100.##Maximum acceleration of follower during outstroke in m/s**2\n",

-      "Fr=pi**2*w**2.*s/2./THETAR**2/100.##Maximum acceleration of follower during return stroke in m/s**2\n",

-      "print'%s %.1f %s %.1f %s '%('Maximum acceleration of follower during outstroke =',Fo,' m/s**2''Maximum acceleration of follower during return stroke= ',Fr,' m/s**2')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Maximum acceleration of follower during outstroke = 6.2  m/s**2Maximum acceleration of follower during return stroke=  24.7  m/s**2 \n"

-       ]

-      }

-     ],

-     "prompt_number": 2

-    },

-    {

-     "cell_type": "heading",

-     "level": 2,

-     "metadata": {},

-     "source": [

-      "Ex5-pg252"

-     ]

-    },

-    {

-     "cell_type": "code",

-     "collapsed": false,

-     "input": [

-      "##CHAPTER 9 ILLUSRTATION 5 PAGE NO 252\n",

-      "##TITLE:CAMS AND FOLLOWERS\n",

-      "import math\n",

-      "pi=3.141\n",

-      "N=1000.##    speed of cam in rpm\n",

-      "w=2.*pi*N/60.##  angular speed in rad/s\n",

-      "s=2.5##   stroke of the follower in cm\n",

-      "THETA=120.*pi/180.##  ANGULAR DISPLACEMENT OF CAM DURING OUTSTROKE IN RAD\n",

-      "THETAR=90.*pi/180.##ANGULAR DISPLACEMENT OF CAM DURING DWELL IN RAD\n",

-      "Vo=2.*w*s/THETA##   Maximum velocity of follower during outstroke in cm/s\n",

-      "Vr=2.*w*s/THETAR##Maximum velocity of follower during return stroke in cm/s\n",

-      "Fo=4.*w**2.*s/THETA**2.##Maximum acceleration of follower during outstroke in m/s**2\n",

-      "Fr=4.*w**2.*s/THETAR**2.##Maximum acceleration of follower during return stroke in m/s**2\n",

-      "print'%s %.1f %s %.1f %s '%('Maximum acceleration of follower during outstroke =',Fo,' m/s**2''Maximum acceleration of follower during return stroke= ',Fr,' m/s**2')\n"

-     ],

-     "language": "python",

-     "metadata": {},

-     "outputs": [

-      {

-       "output_type": "stream",

-       "stream": "stdout",

-       "text": [

-        "Maximum acceleration of follower during outstroke = 25000.0  m/s**2Maximum acceleration of follower during return stroke=  44444.4  m/s**2 \n"

-       ]

-      }

-     ],

-     "prompt_number": 1

-    }

-   ],

-   "metadata": {}

-  }

- ]

-}
\ No newline at end of file
diff --git a/abcd_by_cbvbv/Chapter1.ipynb b/abcd_by_cbvbv/Chapter1.ipynb
deleted file mode 100755
index 1cb4536f..00000000
--- a/abcd_by_cbvbv/Chapter1.ipynb
+++ /dev/null
@@ -1,504 +0,0 @@
-{
- "metadata": {
-  "name": "",
-  "signature": "sha256:b9d3600de62f2e313ebd68d87880d0cad19ed95bdfc9a86e635db985c6359259"
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "UNIT-1:Waves & Vibrations"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example no:1.1,Page no:11"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "\n",
-      "#Variable declaration\n",
-      "n=512   #frequency in Hz\n",
-      "l=67    #wavelength in cm\n",
-      "\n",
-      "#Calculation\n",
-      "v=n*l    #calculating velocity\n",
-      "\n",
-      "#Result\n",
-      "print\"Velocity = \",v,\" cm/sec\"    \n",
-      "print\"NOTE:Calculation mistake in book\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Velocity =  34304  cm/sec\n",
-        "NOTE:Calculation mistake in book\n"
-       ]
-      }
-     ],
-     "prompt_number": 6
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example no:1.2,Page no:11"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "  \n",
-      "\n",
-      "#Variable declaration\n",
-      "v=340   #velocity in m/sec\n",
-      "l=0.68    #wavelength in m\n",
-      "\n",
-      "#Calculation\n",
-      "n=v/l    #calculating frequency\n",
-      "\n",
-      "#Result\n",
-      "print\"Frequency\",n,\"Hz\"    "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Frequency 500.0 Hz\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example no:1.3,Page no:12"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "  \n",
-      "\n",
-      "#Variable declaration\n",
-      "v=3*10**8   #velocity in m/sec\n",
-      "n=500*10**3    #frequency in Hz\n",
-      "\n",
-      "#Calculation\n",
-      "l=v/n    #calculating wavelength\n",
-      "\n",
-      "#Result\n",
-      "print\"Wavelength=\",l,\"m\"    "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Wavelength= 600 m\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example no:1.4,Page no:12"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "  \n",
-      "\n",
-      "#Variable declaration\n",
-      "v=330   #velocity in m/sec\n",
-      "n=560.0    #frequency in Hz\n",
-      "\n",
-      "#Calculation\n",
-      "lamda=v/n    #calculating wavelength\n",
-      "\n",
-      "#Result\n",
-      "print\"lambda=\",round(lamda,3),\"m\"\n",
-      "print\"Distance travelled in 30 vibrations in m = \",round(lamda*30,2),\"m\"    "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "lambda= 0.589 m\n",
-        "Distance travelled in 30 vibrations in m =  17.68 m\n"
-       ]
-      }
-     ],
-     "prompt_number": 7
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example no:1.5,Page no:12"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "import math  \n",
-      "\n",
-      "#Variable declaration\n",
-      "s=90.0      #distance in m\n",
-      "u=0       #initial velocity in m/sec\n",
-      "\n",
-      "#Calculation\n",
-      "t=math.sqrt(90/4.9)     #calculating time using kinematical equation\n",
-      "later=4.56        #Time after which sound is heard\n",
-      "t1=later-t       #calculating time taken by sound to travel\n",
-      "t1=round(t1,2)\n",
-      "v=s/t1       #calculating velocity\n",
-      "\n",
-      "#Result\n",
-      "print\"Velocity in m/sec = \",round(v,2),\"m/s\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Velocity in m/sec =  333.33 m/s\n"
-       ]
-      }
-     ],
-     "prompt_number": 4
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example no:1.6,Page no:13"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "  \n",
-      "\n",
-      "#Variable declaration\n",
-      "l1=1.5    #wavelength in m\n",
-      "l2=2    #wavelength in m\n",
-      "v1=120   #velocity in m/sec\n",
-      "\n",
-      "#Calculation\n",
-      "n=v1/l1     #calculating frequency\n",
-      "v2=n*l2    #calculating velocity\n",
-      "\n",
-      "#Result\n",
-      "print\"Velocity in m/sec = \",v2,\"m/sec\"   "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Velocity in m/sec =  160.0 m/sec\n"
-       ]
-      }
-     ],
-     "prompt_number": 16
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example no:1.7,Page no:14"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "  \n",
-      "\n",
-      "#Variable declaration\n",
-      "l=5641*10**-10    #wavelength in m\n",
-      "c=3*10**8         #velocity in m/sec\n",
-      "u=1.58        #refractive index of glass\n",
-      "\n",
-      "#Calculation\n",
-      "n=c/l          #calculating frequency\n",
-      "cg=c/u         #calculating velocity of light in glass\n",
-      "l1=cg/n       #calculating wavelegth in glass\n",
-      "\n",
-      "#Result\n",
-      "print\"Wavelength in glass in Angstrom =\",l1*10**10,\"Angstrom\"   \n",
-      "print\"\\n\\nNOTE:Calculation ambiguity in book,value of cg is taken as 1.9*10**8 ,Therefore final answer is changed\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Wavelength in glass in Angstrom = 3570.25316456 Angstrom\n",
-        "\n",
-        "\n",
-        "NOTE:Calculation ambiguity in book,value of cg is taken as 1.9*10**8 ,Therefore final answer is changed\n"
-       ]
-      }
-     ],
-     "prompt_number": 4
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example no:1.8,Page no:15"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "  \n",
-      "\n",
-      "#Variable declaration\n",
-      "n=12*10**6         #frequency in Hz\n",
-      "v=3*10**8         #velocity in m/sec\n",
-      "\n",
-      "#Calculation\n",
-      "l=v/n            #calculating wavelength\n",
-      "\n",
-      "#Result\n",
-      "print\"Wavelength in m = \",l,\"m\"   "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Wavelength in m =  25 m\n"
-       ]
-      }
-     ],
-     "prompt_number": 18
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example no:1.9,Page no:15"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "\n",
-      "#Variable declaration\n",
-      "n=400        #frequency in Hz\n",
-      "v=300.0      #velocity in m/sec\n",
-      "\n",
-      "#Calculation\n",
-      "l=v/n            #calculating wavelength\n",
-      "\n",
-      "#Result\n",
-      "print\"Wavelength=\",l,\"m\"   "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Wavelength= 0.75 m\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example no:1.10,Page no:22"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "import math  \n",
-      "\n",
-      "#Variable declaration\n",
-      "a=20       #amplitude in cm\n",
-      "n=6       #frequency per second\n",
-      "\n",
-      "#Calculation\n",
-      "w=2*(math.pi)*n    #omega in radians/sec\n",
-      "\n",
-      "#Result\n",
-      "print\"Omega in radians/sec = \",round(w,1),\"rad/sec\"    \n",
-      "print\"y=\",a,\"sin\",round(w,1),\"t\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Omega in radians/sec =  37.7 rad/sec\n",
-        "y= 20 sin 37.7 t\n"
-       ]
-      }
-     ],
-     "prompt_number": 7
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example no:1.11,Page no:23"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "  \n",
-      "\n",
-      "#Variable declaration\n",
-      "a=6      #amplitude in cm\n",
-      "n=9      #frequency in Hz.\n",
-      "\n",
-      "#Calculation\n",
-      "vmax=2*(math.pi)*n*6   #calculating velocity in cm/sec\n",
-      "acc=-((18*(math.pi))**2)*6   #calculating acc. in m/sec square\n",
-      "\n",
-      "#Result\n",
-      "print\"Maximum velocity in cm/sec = \",round(vmax,2),\"cm/sec\"   \n",
-      "print\"Velocity at extreme position = 0\"    \n",
-      "print\"Accelaration at mean position = 0\"   \n",
-      "print\"Accelaration at extreme position  = \",round(acc,1),\"m/sec^2\"   \n",
-      "print\"\\n\\nNOTE:Calculation mistake in book\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum velocity in cm/sec =  339.29 cm/sec\n",
-        "Velocity at extreme position = 0\n",
-        "Accelaration at mean position = 0\n",
-        "Accelaration at extreme position  =  -19186.5 m/sec^2\n",
-        "\n",
-        "\n",
-        "NOTE:Calculation mistake in book\n"
-       ]
-      }
-     ],
-     "prompt_number": 8
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example no:1.12,Page no:26"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "\n",
-      "#Variable declaration\n",
-      "g=9.8    #gravitational constant\n",
-      "m=50    #mass in kg\n",
-      "l=0.2    #length in m\n",
-      "T=0.6     #time period\n",
-      "\n",
-      "#Calculation\n",
-      "k=(m*g)/l    #calculating constant\n",
-      "m=2450*((T/(2*(math.pi)))**2)   #calcualting mass using given time period\n",
-      "\n",
-      "#Result\n",
-      "print\"Mass of body= \",round(m,2),\"kg\"  \n",
-      "print\"Weight of suspended body=\",round(m,2)*g,\"N\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Mass of body=  22.34 kg\n",
-        "Weight of suspended body= 218.932 N\n"
-       ]
-      }
-     ],
-     "prompt_number": 12
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/abcd_by_cbvbv/Chapter1_1.ipynb b/abcd_by_cbvbv/Chapter1_1.ipynb
deleted file mode 100755
index 1cb4536f..00000000
--- a/abcd_by_cbvbv/Chapter1_1.ipynb
+++ /dev/null
@@ -1,504 +0,0 @@
-{
- "metadata": {
-  "name": "",
-  "signature": "sha256:b9d3600de62f2e313ebd68d87880d0cad19ed95bdfc9a86e635db985c6359259"
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "UNIT-1:Waves & Vibrations"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example no:1.1,Page no:11"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "\n",
-      "#Variable declaration\n",
-      "n=512   #frequency in Hz\n",
-      "l=67    #wavelength in cm\n",
-      "\n",
-      "#Calculation\n",
-      "v=n*l    #calculating velocity\n",
-      "\n",
-      "#Result\n",
-      "print\"Velocity = \",v,\" cm/sec\"    \n",
-      "print\"NOTE:Calculation mistake in book\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Velocity =  34304  cm/sec\n",
-        "NOTE:Calculation mistake in book\n"
-       ]
-      }
-     ],
-     "prompt_number": 6
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example no:1.2,Page no:11"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "  \n",
-      "\n",
-      "#Variable declaration\n",
-      "v=340   #velocity in m/sec\n",
-      "l=0.68    #wavelength in m\n",
-      "\n",
-      "#Calculation\n",
-      "n=v/l    #calculating frequency\n",
-      "\n",
-      "#Result\n",
-      "print\"Frequency\",n,\"Hz\"    "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Frequency 500.0 Hz\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example no:1.3,Page no:12"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "  \n",
-      "\n",
-      "#Variable declaration\n",
-      "v=3*10**8   #velocity in m/sec\n",
-      "n=500*10**3    #frequency in Hz\n",
-      "\n",
-      "#Calculation\n",
-      "l=v/n    #calculating wavelength\n",
-      "\n",
-      "#Result\n",
-      "print\"Wavelength=\",l,\"m\"    "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Wavelength= 600 m\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example no:1.4,Page no:12"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "  \n",
-      "\n",
-      "#Variable declaration\n",
-      "v=330   #velocity in m/sec\n",
-      "n=560.0    #frequency in Hz\n",
-      "\n",
-      "#Calculation\n",
-      "lamda=v/n    #calculating wavelength\n",
-      "\n",
-      "#Result\n",
-      "print\"lambda=\",round(lamda,3),\"m\"\n",
-      "print\"Distance travelled in 30 vibrations in m = \",round(lamda*30,2),\"m\"    "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "lambda= 0.589 m\n",
-        "Distance travelled in 30 vibrations in m =  17.68 m\n"
-       ]
-      }
-     ],
-     "prompt_number": 7
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example no:1.5,Page no:12"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "import math  \n",
-      "\n",
-      "#Variable declaration\n",
-      "s=90.0      #distance in m\n",
-      "u=0       #initial velocity in m/sec\n",
-      "\n",
-      "#Calculation\n",
-      "t=math.sqrt(90/4.9)     #calculating time using kinematical equation\n",
-      "later=4.56        #Time after which sound is heard\n",
-      "t1=later-t       #calculating time taken by sound to travel\n",
-      "t1=round(t1,2)\n",
-      "v=s/t1       #calculating velocity\n",
-      "\n",
-      "#Result\n",
-      "print\"Velocity in m/sec = \",round(v,2),\"m/s\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Velocity in m/sec =  333.33 m/s\n"
-       ]
-      }
-     ],
-     "prompt_number": 4
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example no:1.6,Page no:13"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "  \n",
-      "\n",
-      "#Variable declaration\n",
-      "l1=1.5    #wavelength in m\n",
-      "l2=2    #wavelength in m\n",
-      "v1=120   #velocity in m/sec\n",
-      "\n",
-      "#Calculation\n",
-      "n=v1/l1     #calculating frequency\n",
-      "v2=n*l2    #calculating velocity\n",
-      "\n",
-      "#Result\n",
-      "print\"Velocity in m/sec = \",v2,\"m/sec\"   "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Velocity in m/sec =  160.0 m/sec\n"
-       ]
-      }
-     ],
-     "prompt_number": 16
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example no:1.7,Page no:14"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "  \n",
-      "\n",
-      "#Variable declaration\n",
-      "l=5641*10**-10    #wavelength in m\n",
-      "c=3*10**8         #velocity in m/sec\n",
-      "u=1.58        #refractive index of glass\n",
-      "\n",
-      "#Calculation\n",
-      "n=c/l          #calculating frequency\n",
-      "cg=c/u         #calculating velocity of light in glass\n",
-      "l1=cg/n       #calculating wavelegth in glass\n",
-      "\n",
-      "#Result\n",
-      "print\"Wavelength in glass in Angstrom =\",l1*10**10,\"Angstrom\"   \n",
-      "print\"\\n\\nNOTE:Calculation ambiguity in book,value of cg is taken as 1.9*10**8 ,Therefore final answer is changed\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Wavelength in glass in Angstrom = 3570.25316456 Angstrom\n",
-        "\n",
-        "\n",
-        "NOTE:Calculation ambiguity in book,value of cg is taken as 1.9*10**8 ,Therefore final answer is changed\n"
-       ]
-      }
-     ],
-     "prompt_number": 4
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example no:1.8,Page no:15"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "  \n",
-      "\n",
-      "#Variable declaration\n",
-      "n=12*10**6         #frequency in Hz\n",
-      "v=3*10**8         #velocity in m/sec\n",
-      "\n",
-      "#Calculation\n",
-      "l=v/n            #calculating wavelength\n",
-      "\n",
-      "#Result\n",
-      "print\"Wavelength in m = \",l,\"m\"   "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Wavelength in m =  25 m\n"
-       ]
-      }
-     ],
-     "prompt_number": 18
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example no:1.9,Page no:15"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "\n",
-      "#Variable declaration\n",
-      "n=400        #frequency in Hz\n",
-      "v=300.0      #velocity in m/sec\n",
-      "\n",
-      "#Calculation\n",
-      "l=v/n            #calculating wavelength\n",
-      "\n",
-      "#Result\n",
-      "print\"Wavelength=\",l,\"m\"   "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Wavelength= 0.75 m\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example no:1.10,Page no:22"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "import math  \n",
-      "\n",
-      "#Variable declaration\n",
-      "a=20       #amplitude in cm\n",
-      "n=6       #frequency per second\n",
-      "\n",
-      "#Calculation\n",
-      "w=2*(math.pi)*n    #omega in radians/sec\n",
-      "\n",
-      "#Result\n",
-      "print\"Omega in radians/sec = \",round(w,1),\"rad/sec\"    \n",
-      "print\"y=\",a,\"sin\",round(w,1),\"t\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Omega in radians/sec =  37.7 rad/sec\n",
-        "y= 20 sin 37.7 t\n"
-       ]
-      }
-     ],
-     "prompt_number": 7
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example no:1.11,Page no:23"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "  \n",
-      "\n",
-      "#Variable declaration\n",
-      "a=6      #amplitude in cm\n",
-      "n=9      #frequency in Hz.\n",
-      "\n",
-      "#Calculation\n",
-      "vmax=2*(math.pi)*n*6   #calculating velocity in cm/sec\n",
-      "acc=-((18*(math.pi))**2)*6   #calculating acc. in m/sec square\n",
-      "\n",
-      "#Result\n",
-      "print\"Maximum velocity in cm/sec = \",round(vmax,2),\"cm/sec\"   \n",
-      "print\"Velocity at extreme position = 0\"    \n",
-      "print\"Accelaration at mean position = 0\"   \n",
-      "print\"Accelaration at extreme position  = \",round(acc,1),\"m/sec^2\"   \n",
-      "print\"\\n\\nNOTE:Calculation mistake in book\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum velocity in cm/sec =  339.29 cm/sec\n",
-        "Velocity at extreme position = 0\n",
-        "Accelaration at mean position = 0\n",
-        "Accelaration at extreme position  =  -19186.5 m/sec^2\n",
-        "\n",
-        "\n",
-        "NOTE:Calculation mistake in book\n"
-       ]
-      }
-     ],
-     "prompt_number": 8
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example no:1.12,Page no:26"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "\n",
-      "#Variable declaration\n",
-      "g=9.8    #gravitational constant\n",
-      "m=50    #mass in kg\n",
-      "l=0.2    #length in m\n",
-      "T=0.6     #time period\n",
-      "\n",
-      "#Calculation\n",
-      "k=(m*g)/l    #calculating constant\n",
-      "m=2450*((T/(2*(math.pi)))**2)   #calcualting mass using given time period\n",
-      "\n",
-      "#Result\n",
-      "print\"Mass of body= \",round(m,2),\"kg\"  \n",
-      "print\"Weight of suspended body=\",round(m,2)*g,\"N\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Mass of body=  22.34 kg\n",
-        "Weight of suspended body= 218.932 N\n"
-       ]
-      }
-     ],
-     "prompt_number": 12
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/abcd_by_cbvbv/screenshots/k1.png b/abcd_by_cbvbv/screenshots/k1.png
deleted file mode 100755
index 995e3ebf..00000000
--- a/abcd_by_cbvbv/screenshots/k1.png
+++ /dev/null
diff --git a/abcd_by_cbvbv/screenshots/k2.png b/abcd_by_cbvbv/screenshots/k2.png
deleted file mode 100755
index f0b1ec67..00000000
--- a/abcd_by_cbvbv/screenshots/k2.png
+++ /dev/null
diff --git a/abcd_by_cbvbv/screenshots/k2_1.png b/abcd_by_cbvbv/screenshots/k2_1.png
deleted file mode 100755
index f0b1ec67..00000000
--- a/abcd_by_cbvbv/screenshots/k2_1.png
+++ /dev/null
diff --git a/abcd_by_cbvbv/screenshots/k3.png b/abcd_by_cbvbv/screenshots/k3.png
deleted file mode 100755
index 90f96617..00000000
--- a/abcd_by_cbvbv/screenshots/k3.png
+++ /dev/null
diff --git a/abcd_by_cbvbv/screenshots/k3_1.png b/abcd_by_cbvbv/screenshots/k3_1.png
deleted file mode 100755
index 90f96617..00000000
--- a/abcd_by_cbvbv/screenshots/k3_1.png
+++ /dev/null
diff --git a/abcd_by_cbvbv/screenshots/k3_2.png b/abcd_by_cbvbv/screenshots/k3_2.png
deleted file mode 100755
index 90f96617..00000000
--- a/abcd_by_cbvbv/screenshots/k3_2.png
+++ /dev/null
diff --git a/t_by_t/README.txt b/t_by_t/README.txt
deleted file mode 100755
index ac59ae1b..00000000
--- a/t_by_t/README.txt
+++ /dev/null
@@ -1,10 +0,0 @@
-Contributed By: t t
-Course: mtech
-College/Institute/Organization: t
-Department/Designation: t
-Book Title: t
-Author: t
-Publisher: t
-Year of publication: 1
-Isbn: 4
-Edition: 1
\ No newline at end of file
diff --git a/t_by_t/anubhav.ipynb b/t_by_t/anubhav.ipynb
deleted file mode 100755
index 61f4f2a7..00000000
--- a/t_by_t/anubhav.ipynb
+++ /dev/null
@@ -1,335 +0,0 @@
-{


- "metadata": {


-  "name": "",


-  "signature": "sha256:695be6f5d590e853c0078224291d8b06e5e832ca7707f21f65e700432eacc419"


- },


- "nbformat": 3,


- "nbformat_minor": 0,


- "worksheets": [


-  {


-   "cells": [


-    {


-     "cell_type": "heading",


-     "level": 1,


-     "metadata": {},


-     "source": [


-      "Chapter15:POWER SYSTEMS"


-     ]


-    },


-    {


-     "cell_type": "heading",


-     "level": 2,


-     "metadata": {},


-     "source": [


-      "Ex15.1:pg-696"


-     ]


-    },


-    {


-     "cell_type": "code",


-     "collapsed": false,


-     "input": [


-      "V1=250\n",


-      "V2=480\n",


-      "Vol2_by_Vol1=V1/V2\n",


-      "\n",


-      "sav=(1-Vol2_by_Vol1)*100\n",


-      "print(sav)\n"


-     ],


-     "language": "python",


-     "metadata": {},


-     "outputs": [


-      {


-       "output_type": "stream",


-       "stream": "stdout",


-       "text": [


-        "100\n"


-       ]


-      }


-     ],


-     "prompt_number": 2


-    },


-    {


-     "cell_type": "heading",


-     "level": 2,


-     "metadata": {},


-     "source": [


-      "Ex15.2:pg-697"


-     ]


-    },


-    {


-     "cell_type": "code",


-     "collapsed": false,


-     "input": [


-      "P=5E6\n",


-      "pf=0.85\n",


-      "V=33000\n",


-      "l=50000\n",


-      "rho=3E-8\n",


-      "Pt=P*pf\n",


-      "Pl=Pt*0.1\n",


-      "I=P/V\n",


-      "A1=2*I*I*rho*l/Pl\n",


-      "Vol1=2*l*A1\n",


-      "print(Vol1)\n",


-      "Il=P/sqrt(3)/V\n",


-      "A2=3*Il*Il*rho*l/Pl\n",


-      "Vol2=3*l*A2\n",


-      "print(Vol2)\n"


-     ],


-     "language": "python",


-     "metadata": {},


-     "outputs": [


-      {


-       "output_type": "stream",


-       "stream": "stdout",


-       "text": [


-        "16.2048290391\n",


-        "12.1536217793"


-       ]


-      },


-      {


-       "output_type": "stream",


-       "stream": "stdout",


-       "text": [


-        "\n"


-       ]


-      }


-     ],


-     "prompt_number": 1


-    },


-    {


-     "cell_type": "heading",


-     "level": 2,


-     "metadata": {},


-     "source": [


-      "Ex15.3:pg-698"


-     ]


-    },


-    {


-     "cell_type": "code",


-     "collapsed": false,


-     "input": [


-      "import math\n",


-      "f=50\n",


-      "w=2*math.pi*f\n",


-      "I=0.8\n",


-      "V=220\n",


-      "P=75\n",


-      "phi=math.acos(P/V/I)\n",


-      "\n",


-      "phi_new=math.acos(0.9)\n",


-      "Ic=I*cos(phi)*(tan(phi)-tan(phi_new))\n",


-      "C=Ic/V/w\n",


-      "print\"C=\",round(C,8)\n",


-      "\n",


-      "phi_new=math.acos(1)\n",


-      "Ic=I*cos(phi)*(tan(phi)-tan(phi_new))\n",


-      "C=Ic/V/w\n",


-      "print\"C=\",round(C,8)\n"


-     ],


-     "language": "python",


-     "metadata": {},


-     "outputs": [


-      {


-       "output_type": "stream",


-       "stream": "stdout",


-       "text": [


-        "C= 1.157e-05\n",


-        "C= 1.157e-05\n"


-       ]


-      }


-     ],


-     "prompt_number": 7


-    },


-    {


-     "cell_type": "heading",


-     "level": 2,


-     "metadata": {},


-     "source": [


-      "Ex15.4:pg-698"


-     ]


-    },


-    {


-     "cell_type": "code",


-     "collapsed": false,


-     "input": [


-      "import math\n",


-      "Cond_cost=100\n",


-      "charge=60\n",


-      "phi2=math.asin(0.1*Cond_cost/charge)\n",


-      "pf=cos(phi2)\n",


-      "print(pf)\n"


-     ],


-     "language": "python",


-     "metadata": {},


-     "outputs": [


-      {


-       "output_type": "stream",


-       "stream": "stdout",


-       "text": [


-        "0.986013297183\n"


-       ]


-      }


-     ],


-     "prompt_number": 8


-    },


-    {


-     "cell_type": "heading",


-     "level": 2,


-     "metadata": {},


-     "source": [


-      "Ex15.5:pg-699"


-     ]


-    },


-    {


-     "cell_type": "code",


-     "collapsed": false,


-     "input": [


-      "\n",


-      "Oc=400000\n",


-      "pf1=0.8\n",


-      "phi1=math.acos(pf1)\n",


-      "ab=Oc/cos(phi1)*sin(phi1)\n",


-      "pf2=0.25\n",


-      "phi3=math.acos(pf2)\n",


-      "pf2=0.484\n",


-      "\n",


-      "gammaa=(ab-pf2*Oc)/(pf2*cos(phi3)+sin(phi3))\n",


-      "print(gammaa)\n"


-     ],


-     "language": "python",


-     "metadata": {},


-     "outputs": [


-      {


-       "output_type": "stream",


-       "stream": "stdout",


-       "text": [


-        "97682.2645812\n"


-       ]


-      }


-     ],


-     "prompt_number": 9


-    },


-    {


-     "cell_type": "heading",


-     "level": 2,


-     "metadata": {},


-     "source": [


-      "Ex15.6:pg-700"


-     ]


-    },


-    {


-     "cell_type": "code",


-     "collapsed": false,


-     "input": [


-      "f=50\n",


-      "w=2*math.pi*f\n",


-      "P=2E6\n",


-      "V=11000\n",


-      "pf=0.8\n",


-      "phi=math.acos(pf)\n",


-      "Xl=10\n",


-      "IR=P/sqrt(3)/V/pf\n",


-      "Vr=V/sqrt(3)\n",


-      "Vs=Vr+IR*Xl*sin(phi)\n",


-      "Vsll=Vs*sqrt(3)\n",


-      "print(Vsll)\n",


-      "VR=Vsll/V-1\n",


-      "print(VR)\n",


-      "\n",


-      "pf=1\n",


-      "print(pf)\n",


-      "Qc=P*tan(phi)\n",


-      "C=Qc/V/V/w\n",


-      "print(C)\n"


-     ],


-     "language": "python",


-     "metadata": {},


-     "outputs": [


-      {


-       "output_type": "stream",


-       "stream": "stdout",


-       "text": [


-        "12363.6363636\n",


-        "0.123966942149\n",


-        "1\n",


-        "3.94599032459e-05\n"


-       ]


-      }


-     ],


-     "prompt_number": 10


-    },


-    {


-     "cell_type": "heading",


-     "level": 2,


-     "metadata": {},


-     "source": [


-      "Ex15.7:pg-701"


-     ]


-    },


-    {


-     "cell_type": "code",


-     "collapsed": false,


-     "input": [


-      "f=50\n",


-      "w=2*math.pi*f\n",


-      "V=33000\n",


-      "Vr=V/sqrt(3)\n",


-      "P=24E6/3\n",


-      "pf=0.8\n",


-      "phi=math.acos(pf)\n",


-      "Ia=P/Vr/pf\n",


-      "Rl=4.0\n",


-      "Xl=20\n",


-      "Vs=Vr+Ia*(Xl*sin(phi)+Rl*cos(phi))\n",


-      "Vsll=sqrt(3)*Vs\n",


-      "VR=Vsll/V-1\n",


-      "print(Vsll)\n",


-      "Ia=Ia*exp(-1j*phi)\n",


-      "print(norm(Ia))\n",


-      "\n",


-      "phi1=math.atan(-Rl/Xl)\n",


-      "pf=cos(phi1)\n",


-      "Ia1=P/Vr/pf\n",


-      "Ia1=Ia1*exp(-1j*phi1)   #calculation mistake in the book at this step\n",


-      "\n",


-      "Ic=Ia1-Ia\n",


-      "C=norm(Ic/w/Vr)\n",


-      "print(C)\n",


-      "\n",


-      "LL1=norm(Ia*Ia*Rl)\n",


-      "effi1=P/(P+LL1)\n",


-      "LL2=norm(Ia1*Ia1*Rl)\n",


-      "effi2=P/(P+LL2)\n",


-      "print(effi1)\n",


-      "print(effi2)\n"


-     ],


-     "language": "python",


-     "metadata": {},


-     "outputs": [


-      {


-       "output_type": "stream",


-       "stream": "stdout",


-       "text": [


-        "46818.1818182\n",


-        "524.863881081"


-       ]


-      },


-      {


-       "output_type": "stream",


-       "stream": "stdout",


-       "text": [


-        "\n",


-        "6.66433921487e-05\n",


-        "0.878934624697\n",


-        "0.916018976481\n"


-       ]


-      }


-     ],


-     "prompt_number": 11


-    }


-   ],


-   "metadata": {}


-  }


- ]


-}
\ No newline at end of file
diff --git a/t_by_t/screenshots/blank1.png b/t_by_t/screenshots/blank1.png
deleted file mode 100755
index e69de29b..00000000
--- a/t_by_t/screenshots/blank1.png
+++ /dev/null
diff --git a/t_by_t/screenshots/blank1_(another_copy).png b/t_by_t/screenshots/blank1_(another_copy).png
deleted file mode 100755
index e69de29b..00000000
--- a/t_by_t/screenshots/blank1_(another_copy).png
+++ /dev/null
diff --git a/t_by_t/screenshots/blank1_(copy).png b/t_by_t/screenshots/blank1_(copy).png
deleted file mode 100755
index e69de29b..00000000
--- a/t_by_t/screenshots/blank1_(copy).png
+++ /dev/null