adding books

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diff --git a/Engineering_Physics/Chapter1.ipynb b/Engineering_Physics/Chapter1.ipynb
new file mode 100755
index 00000000..a3614569
--- /dev/null
+++ b/Engineering_Physics/Chapter1.ipynb
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+{
+ "metadata": {
+  "name": "Chapter1",
+  "signature": "sha256:e55f587b2da98ead68f73bb2b4d29bef91aa67eb577c460fb9dcaab92acc4339"
+ },
+ "nbformat": 3,
+ "nbformat_minor": 0,
+ "worksheets": [
+  {
+   "cells": [
+    {
+     "cell_type": "heading",
+     "level": 1,
+     "metadata": {},
+     "source": "1: Ultrasonics"
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 1.1, Page number 20"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#Variable declaration\nv = 1440;         #velocity of ultrasonic waves(m/s)\nt = 0.33;         #time elapsed(s)\n\n#Calculation\nd = v*t;      #distance travelled(m)\nd1 = d/2;     #depth of submarine(m)\n\n#Result\nprint \"depth of the submerged submarine is\",d1, \"m\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "depth of the submerged submarine is 237.6 m\n"
+      }
+     ],
+     "prompt_number": 1
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 1.2, Page number 21"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\nl = 40;     #length of iron rod(mm)\nE = 115*10**9;      #Young's modulus(N/m**2)\nrho = 7.25*10**3;   #density of pure iron(kg/m**3)\n\n#Calculation\nl = l*10**-3;     #length of iron rod(m)\nnew = (1/(2*l))*math.sqrt(E/rho);     #natural frequency of the rod(Hz)\nnew = new*10**-3;             #natural frequency of the rod(kHz)\nnew=math.ceil(new*10**3)/10**3;   #rounding off to 3 decimals\n\n#Result\nprint \"depth of the submerged submarine is\",new, \"kHz\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "depth of the submerged submarine is 49.785 kHz\n"
+      }
+     ],
+     "prompt_number": 2
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 1.3, Page number 21"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\nl = 1;     #length of quartz crystal(mm)\nE = 7.9*10**10;      #Young's modulus(N/m**2)\nrho = 2650;   #density(kg/m**3)\n\n#Calculation\nl = l*10**-3;     #length of iron rod(m)\nnew = (1/(2*l))*math.sqrt(E/rho);     #natural frequency of the rod(Hz)\nnew = new*10**-6;                   \nnew=math.ceil(new*10**2)/10**2;   #rounding off to 2 decimals\n\n#Result\nprint \"fundamental frequency of crystal is\",new, \"*10**6 Hz\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "fundamental frequency of crystal is 2.73 *10**6 Hz\n"
+      }
+     ],
+     "prompt_number": 3
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 1.4, Page number 22"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\nd = 0.55;        #distance between 2 constructive antinodes(mm)\nnew = 1.5;      #frequency of crystal(MHz)\n \n#Calculation\nnew = new*10**6;        #frequency of crystal(Hz)\nd = d*10**-3;     #distance between 2 constructive antinodes(m)\n#distance between 2 antinodes is given by lamda/2\nlamda = 2*d;      #wavelength of ultrasonic waves(m)\nv = new*lamda;       #velocity of waves(m/s)\n\n#Result\nprint \"velocity of waves is\",int(v), \"m/s\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "velocity of waves is 1650 m/s\n"
+      }
+     ],
+     "prompt_number": 4
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 1.5, Page number 22"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\nl = 50;     #length of rod(mm)\nE = 11.5*10**10;      #Young's modulus(N/m**2)\nrho = 7250;   #density(kg/m**3)\n\n#Calculation\nl = l*10**-3;     #length of iron rod(m)\nnew = (1/(2*l))*math.sqrt(E/rho);     #natural frequency of the rod(Hz)\nnew = new*10**-3;       #natural frequency of the rod(kHz)\nnew = math.ceil(new*10**2)/10**2;   #rounding off to 2 decimals\n\n#Result\nprint \"natural frequency of rod is\",new, \"kHz\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "natural frequency of rod is 39.83 kHz\n"
+      }
+     ],
+     "prompt_number": 5
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 1.6, Page number 22"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\nl = 2;     #length of crystal(mm)\nE = 7.9*10**10;      #Young's modulus(N/m**2)\nrho = 2650;   #density(kg/m**3)\n\n#Calculation\nl = l*10**-3;     #length of iron rod(m)\nnew = (1/(2*l))*math.sqrt(E/rho);     #natural frequency of the rod(Hz)\nnew = new*10**-6;         #natural frequency of the rod(MHz)\nnew=math.ceil(new*10**3)/10**3;   #rounding off to 3 decimals\n\n#Result\nprint \"frequency of crystal is\",new, \"MHz\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "frequency of crystal is 1.365 MHz\n"
+      }
+     ],
+     "prompt_number": 6
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 1.7, Page number 23"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\nl = 3;     #length of crystal(mm)\nE = 8*10**10;      #Young's modulus(N/m**2)\nrho = 2500;   #density(kg/m**3)\n\n#Calculation\nl = l*10**-3;     #length of iron rod(m)\nnew = (1/(2*l))*math.sqrt(E/rho);     #natural frequency of the rod(Hz)\nnew = new*10**-3;         #natural frequency of the rod(kHz) \nnew=math.ceil(new*10**2)/10**2;   #rounding off to 2 decimals\n\n#Result\nprint \"frequency of crystal is\",new, \"kHz\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "frequency of crystal is 942.81 kHz\n"
+      }
+     ],
+     "prompt_number": 8
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 1.8, Page number 23"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\nl = 1.5;     #length of crystal(mm)\nE = 7.9*10**10;      #Young's modulus(N/m**2)\nrho = 2650;   #density(kg/m**3)\n\n#Calculation\nl = l*10**-3;     #length of iron rod(m)\nnew = (1/(2*l))*math.sqrt(E/rho);     #natural frequency of the rod(Hz)\nnew = new*10**-6;         #natural frequency of the rod(MHz) \nnew=math.ceil(new*10**2)/10**2;   #rounding off to 2 decimals\n\n#Result\nprint \"frequency of crystal is\",new, \"MHz\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "frequency of crystal is 1.82 MHz\n"
+      }
+     ],
+     "prompt_number": 10
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 1.9, Page number 24"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#Variable declaration\nv = 1440;         #velocity of ultrasonic waves(m/s)\nt = 0.95;         #time elapsed(s)\n\n#Calculation\nd = v*t;      #distance travelled(m)\nd1 = d/2;     #depth of sea(m)\n\n#Result\nprint \"depth of the submerged submarine is\",int(d1), \"m\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "depth of the submerged submarine is 684 m\n"
+      }
+     ],
+     "prompt_number": 11
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 1.10, Page number 24"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#Variable declaration\nv = 1440;         #velocity of ultrasonic waves(m/s)\nt = 0.83;         #time elapsed(s)\n\n#Calculation\nd = v*t;      #distance travelled(m)\nd1 = d/2;     #depth of submarine(m)\n\n#Result\nprint \"depth of the submerged submarine is\",d1, \"m\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "depth of the submerged submarine is 597.6 m\n"
+      }
+     ],
+     "prompt_number": 12
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 1.11, Page number 24"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\naS = 1050;      #total absorption inside hall(Sabine)\nV = 9000;       #volume of cinema hall(m**3)\n\n#Calculation\nT = 0.165*V/aS;     #reverberation time of hall(s)\nT = math.ceil(T*10**4)/10**4;   #rounding off to 4 decimals\n\n#Result\nprint \"reverberation time of the hall is\",T, \"s\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "reverberation time of the hall is 1.4143 s\n"
+      }
+     ],
+     "prompt_number": 13
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 1.12, Page number 25"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\na = 0.65;      #average absorption coefficient(Sabine/m**2)\nV = 13500;       #volume of auditorium(m**3)\nT = 1.2;         #reverberation time of hall(s)\n\n#Calculation\nS = 0.165*V/(a*T);     #reverberation time of hall(s)\nS = math.ceil(S*10)/10;   #rounding off to 1 decimal\n\n#Result\nprint \"total area of interior surface is\",S, \"m**2\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "total area of interior surface is 2855.8 m**2\n"
+      }
+     ],
+     "prompt_number": 14
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 1.13, Page number 25"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\nV = 15000;       #volume of cinema hall(m**3)\nT1 = 1.3;        #initial reverberation time of hall(s)\na1S1 = 300;      #number of chairs placed\n\n#Calculation\naS = 0.165*V/T1;         #total absorption of hall\nT2 = (0.165*V)/(aS+a1S1);      #reverberation time of hall after adding chairs(s)\nT2 = math.ceil(T2*10**4)/10**4;   #rounding off to 4 decimals\n\n#Result\nprint \"reverberation time of the hall after adding chairs is\",T2, \"s\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "reverberation time of the hall after adding chairs is 1.1231 s\n"
+      }
+     ],
+     "prompt_number": 15
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 1.14, Page number 26"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#Variable declaration\nv = 1440;         #velocity of ultrasonic waves(m/s)\nt = 0.5;         #time elapsed(s)\n\n#Calculation\nd = v*t;      #distance travelled(m)\nd1 = d/2;     #depth of submarine(m)\n\n#Result\nprint \"depth of the submerged submarine is\",int(d1), \"m\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "depth of the submerged submarine is 360 m\n"
+      }
+     ],
+     "prompt_number": 16
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 1.15, Page number 26"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\nd = 0.4;        #distance between 2 constructive antinodes(mm)\nnew = 1.5;      #frequency of crystal(MHz)\n \n#Calculation\nnew = new*10**6;        #frequency of crystal(Hz)\nd = d*10**-3;     #distance between 2 constructive antinodes(m)\n#distance between 2 antinodes is given by lamda/2\nlamda = 2*d;      #wavelength of ultrasonic waves(m)\nv = new*lamda;       #velocity of waves(m/s)\n\n#Result\nprint \"velocity of waves is\",int(v), \"m/s\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "velocity of waves is 1200 m/s\n"
+      }
+     ],
+     "prompt_number": 17
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 1.16, Page number 26"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\nl = 40;     #length of iron rod(mm)\nE = 11.5*10**10;      #Young's modulus(N/m**2)\nrho = 7250;   #density of pure iron(kg/m**3)\n\n#Calculation\nl = l*10**-3;     #length of iron rod(m)\nnew = (1/(2*l))*math.sqrt(E/rho);     #natural frequency of the rod(Hz)\nnew = new*10**-3;             #natural frequency of the rod(kHz)\nnew=math.ceil(new*10**3)/10**3;   #rounding off to 3 decimals\n\n#Result\nprint \"depth of the submerged submarine is\",new, \"kHz\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "depth of the submerged submarine is 49.785 kHz\n"
+      }
+     ],
+     "prompt_number": 18
+    }
+   ],
+   "metadata": {}
+  }
+ ]
+}
\ No newline at end of file
diff --git a/Engineering_Physics/Chapter10.ipynb b/Engineering_Physics/Chapter10.ipynb
new file mode 100755
index 00000000..051ee9c1
--- /dev/null
+++ b/Engineering_Physics/Chapter10.ipynb
@@ -0,0 +1,62 @@
+{
+ "metadata": {
+  "name": "Chapter10"
+ },
+ "nbformat": 3,
+ "nbformat_minor": 0,
+ "worksheets": [
+  {
+   "cells": [
+    {
+     "cell_type": "heading",
+     "level": 1,
+     "metadata": {},
+     "source": "10: Dielectric Materials"
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 10.1, Page number 289"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\nepsilon_r = 1.0000684;            #dielectric constant\nN = 2.7*10**25;                   #number of atoms(per m**3)\nepsilon0 = 8.85*10**-12;          #permittivity of free space\n\n#Calculation\nalpha_e = epsilon0*(epsilon_r-1)/N;       #electronic polarizability(Fm**2)\n\n#Result\nprint \"electronic polarizability is\",alpha_e,\"Fm**2\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "electronic polarizability is 2.242e-41 Fm**2\n"
+      }
+     ],
+     "prompt_number": 1
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 10.2, Page number 290"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\nepsilon_r = 1.0024;            #relative permittivity\nN = 2.7*10**25;                   #number of atoms(per m**3)\nepsilon0 = 8.85*10**-12;          #permittivity of free space\n\n#Calculation\nalpha_e = epsilon0*(epsilon_r-1)/N;       #electronic polarizability(Fm**2)\n\n#Result\nprint \"electronic polarizability is\",alpha_e,\"Fm**2\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "electronic polarizability is 7.86666666667e-40 Fm**2\n"
+      }
+     ],
+     "prompt_number": 2
+    }
+   ],
+   "metadata": {}
+  }
+ ]
+}
\ No newline at end of file
diff --git a/Engineering_Physics/Chapter2.ipynb b/Engineering_Physics/Chapter2.ipynb
new file mode 100755
index 00000000..fff10b22
--- /dev/null
+++ b/Engineering_Physics/Chapter2.ipynb
@@ -0,0 +1,84 @@
+{
+ "metadata": {
+  "name": "Chapter2",
+  "signature": "sha256:ac80f9dfe1725f11a5d4ce0fbda5ffed825d99c680f116629e5e3fcb8b69c198"
+ },
+ "nbformat": 3,
+ "nbformat_minor": 0,
+ "worksheets": [
+  {
+   "cells": [
+    {
+     "cell_type": "heading",
+     "level": 1,
+     "metadata": {},
+     "source": "2: Lasers"
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 2.1, Page number 52"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\nlamda = 590;        #wavelength(nm)\nh = 6.625*10**-34;       #planck's constant\nc = 3*10**8;            #velocity of light(m/s)\nk = 1.38*10**-23;       #boltzmann's constant\nT = 523;                #temperature(Kelvin)\n\n#Calculation\nlamda = lamda*10**-9;      #wavelength(m)      \n#n1byn2 = math.exp(-(E2-E1)/(k*T))\n#but E2-E1 = h*new and new = c/lamda\n#therefore n1byn2 = math.exp(-h*c/(lamda*k*T))\nn1byn2 = math.exp(-h*c/(lamda*k*T));\n\n#Result\nprint \"relative population of Na atoms is\",n1byn2",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "relative population of Na atoms is 5.36748316686e-21\n"
+      }
+     ],
+     "prompt_number": 1
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 2.2, Page number 53"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\nlamda = 590;        #wavelength(nm)\nh = 6.625*10**-34;       #planck's constant\nc = 3*10**8;            #velocity of light(m/s)\nk = 1.38*10**-23;       #boltzmann's constant\nT = 523;                #temperature(Kelvin)\n\n#Calculation\nlamda = lamda*10**-9;      #wavelength(m)      \n#n21dashbyn21 = 1/(math.exp(h*new/(k*T))-1)\n#but new = c/lamda\n#therefore n21dashbyn21 = 1/(math.exp(h*c/(lamda*k*T))-1)\nA = math.exp(h*c/(lamda*k*T))-1;\nn21dashbyn21 = 1/A;    \n\n#Result\nprint \"ratio of stimulated to spontaneous emission is\",n21dashbyn21\nprint \"answer given in the book is wrong\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "ratio of stimulated to spontaneous emission is 5.36748316686e-21\nanswer given in the book is wrong\n"
+      }
+     ],
+     "prompt_number": 2
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 2.3, Page number 53"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\nlamda = 632.8;        #wavelength of laser(nm)\nh = 6.625*10**-34;       #planck's constant\nc = 3*10**8;            #velocity of light(m/s)\np = 3.147;              #output power(mW)\n\n#Calculation\np = p*10**-3;          #output power(W)\nlamda = lamda*10**-9;      #wavelength(m)      \nnew = c/lamda;             #frequency(Hz)\nE = h*new;                 #energy of each photon(J)\nEm = p*60;                 #energy emitted per minute(J/min)\nN = Em/E;                  #number of photons emitted per second\n\n#Result\nprint \"number of photons emitted per second is\",N",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "number of photons emitted per second is 6.01183879245e+17\n"
+      }
+     ],
+     "prompt_number": 3
+    }
+   ],
+   "metadata": {}
+  }
+ ]
+}
\ No newline at end of file
diff --git a/Engineering_Physics/Chapter3.ipynb b/Engineering_Physics/Chapter3.ipynb
new file mode 100755
index 00000000..9e2d3109
--- /dev/null
+++ b/Engineering_Physics/Chapter3.ipynb
@@ -0,0 +1,83 @@
+{
+ "metadata": {
+  "name": "Chapter3"
+ },
+ "nbformat": 3,
+ "nbformat_minor": 0,
+ "worksheets": [
+  {
+   "cells": [
+    {
+     "cell_type": "heading",
+     "level": 1,
+     "metadata": {},
+     "source": "3: Fibre Optics and Applications"
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 3.1, Page number 84"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\nn1 = 1.5;          #refractive index of core\nn2 = 1.47;         #refractive index of cladding\nn0 = 1;            #refractive index of air\na = 180/math.pi;        #conversion factor of radian to degree\n\n#Calculation\nNA = math.sqrt((n1**2)-(n2**2));     #numerical aperture\nNA=math.ceil(NA*10)/10;   #rounding off to 1 decimal\nalpha_m = math.asin(NA/n0);         #acceptance angle(radian)\nalpha_m = alpha_m*a;                #acceptance angle(degrees)\nalpha_m=math.ceil(alpha_m*10**2)/10**2;   #rounding off to 2 decimals\nphi_m = math.asin(NA/n1);           #phase angle(radian)\nphi_m = phi_m*a;                    #phase angle(degrees)\nphi_m=math.ceil(phi_m*10**2)/10**2;   #rounding off to 2 decimals\ntheta_c = math.asin(n2/n1);         #critical angle(radian)\ntheta_c = theta_c*a;                #critical angle(degrees)\ntheta_c=math.ceil(theta_c*10**3)/10**3;   #rounding off to 3 decimals\n\n#Result\nprint \"numerical aperture is\",NA\nprint \"acceptance angle is\",alpha_m,\"degrees\"\nprint \"phase angle is\",phi_m,\"degrees\"\nprint \"critical angle is\",theta_c,\"degrees\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "numerical aperture is 0.3\nacceptance angle is 17.46 degrees\nphase angle is 11.54 degrees\ncritical angle is 78.522 degrees\n"
+      }
+     ],
+     "prompt_number": 3
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 3.2, Page number 85"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\nn1 = 1.5;          #refractive index of core\nn2 = 1.47;         #refractive index of cladding\nc = 3*10**8;       #velocity of light(m/sec)\n\n#Calculation\ndeltatbyL = (n1/n2)*((n1-n2)/c);\n\n#Result\nprint \"pulse broadening per unit length is\",deltatbyL,\"s/m\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "pulse broadening per unit length is 1.02040816327e-10 s/m\n"
+      }
+     ],
+     "prompt_number": 2
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 3.3, Page number 85"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\nphi_m = 11.54;       #phase angle(degrees)\na = 0.5*10**-4;\nx = math.pi/180;       #conversion factor from degrees to radians\n\n#Calculation\nphi_m = phi_m*x;      #phase angle(radian)\nL = a/math.tan(phi_m);      #length(m)\nn = 1/(2*L);          #total number of internal reflections(m-1)\n\n#Result\nprint \"alpha = 0 rays have no reflection. hence there are zero reflections for 1 metre.\"\nprint \"alpha = alpha_m rays have\",int(n),\"m-1 internal reflections\"\nprint \"answer given in the book is wrong\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "alpha = 0 rays have no reflection. hence there are zero reflections for 1 metre.\nalpha = alpha_m rays have 2041 m-1 internal reflections\nanswer given in the book is wrong\n"
+      }
+     ],
+     "prompt_number": 7
+    }
+   ],
+   "metadata": {}
+  }
+ ]
+}
\ No newline at end of file
diff --git a/Engineering_Physics/Chapter4.ipynb b/Engineering_Physics/Chapter4.ipynb
new file mode 100755
index 00000000..5651b165
--- /dev/null
+++ b/Engineering_Physics/Chapter4.ipynb
@@ -0,0 +1,209 @@
+{
+ "metadata": {
+  "name": "Chapter4"
+ },
+ "nbformat": 3,
+ "nbformat_minor": 0,
+ "worksheets": [
+  {
+   "cells": [
+    {
+     "cell_type": "heading",
+     "level": 1,
+     "metadata": {},
+     "source": "4: Quantum Physics"
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 4.1, Page number 117"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\nc = 3*10**8;       #velocity of light(m/sec)\nh = 6.62*10**-34;     #planck's constant\nlamda = 1.2;          #wavelength of photon(Angstrom)\ne = 1.6*10**-19;      #conversion factor from J to eV\n\n#Calculation\nlamda = lamda*10**-10;       #wavelength of photon(m)\nE = (h*c)/(lamda*e);         #energy of photon(eV)\nE=math.ceil(E*10)/10;   #rounding off to 1 decimal\np = h/lamda;            #momentum of photon(kg m/s)\n\n#Result\nprint \"energy of the photon is\",E,\"eV\"\nprint \"momentum of the photon is\",p,\"kg m/s\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "energy of the photon is 10343.8 eV\nmomentum of the photon is 5.51666666667e-24 kg m/s\n"
+      }
+     ],
+     "prompt_number": 1
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 4.2, Page number 117"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\nh = 6.625*10**-34;     #planck's constant\nnew = 900;             #frequency(kHz)\nE1 = 10;               #power radiated(kW)\n\n#Calculation\nE1 = E1*10**3;         #power radiated(W)\nnew = new*10**3;       #frequency(Hz)\nE = h*new;         #energy of photon(J)\nN = E1/E;          #number of photons emitted \n\n#Result\nprint \"number of photons emitted per second is\",N",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "number of photons emitted per second is 1.67714884696e+31\n"
+      }
+     ],
+     "prompt_number": 2
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 4.3, Page number 118"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\nc = 3*10**8;       #velocity of light(m/sec)\nh = 6.63*10**-34;     #planck's constant\nlamda = 5893;         #wavelength of photon(Angstrom)\nE1 = 100;             #power of lamp(W) \n\n#Calculation\nlamda = lamda*10**-10;       #wavelength of photon(m)\nE = h*c/lamda;         #energy of photon(J)\nN = E1/E;          #number of photons emitted \n\n#Result\nprint \"number of photons emitted per second is\",N\nprint \"answer given in the book is wrong\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "number of photons emitted per second is 2.96279537456e+20\nanswer given in the book is wrong\n"
+      }
+     ],
+     "prompt_number": 3
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 4.4, Page number 118"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\nc = 3*10**8;       #velocity of light(m/sec)\nh = 6.6*10**-34;     #planck's constant\nm0 = 9.1*10**-31;        #mass of photon(kg)\ntheta = 30;              #viewing angle(degrees)\nlamda = 2.8*10**-10;         #wavelength of photon(m)\n\n#Calculation\nx = math.pi/180;       #conversion factor from degrees to radians\ntheta = theta*x;       #viewing angle(radian) \nlamda_dash = (2*h*(math.sin(theta/2))**2/(m0*c))+lamda;        #wavelength of scattered radiation(m)\nlamda_dash = lamda_dash*10**10;           #wavelength of scattered radiation(Angstrom)\nlamda_dash=math.ceil(lamda_dash*10**5)/10**5;   #rounding off to 5 decimals\n\n#Result\nprint \"wavelength of scattered radiation is\",lamda_dash,\"Angstrom\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "wavelength of scattered radiation is 2.80324 Angstrom\n"
+      }
+     ],
+     "prompt_number": 4
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 4.5, Page number 119"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\nh = 6.6*10**-34;     #planck's constant\nm = 0.040;        #mass of bullet(kg)\nv = 1;            #speed of bullet(km/s)\n\n#Calculation\nv = v*10**3;      #speed of bullet(m/s)\np = m*v;          #momemtun of bullet(kg m/s)\nlamda = h/p;      #deBroglie wavelength(m)\nlamda = lamda*10**10;     #deBroglie wavelength(Angstrom)\n\n#Result\nprint \"deBroglie wavelength is\",lamda,\"Angstrom\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "deBroglie wavelength is 1.65e-25 Angstrom\n"
+      }
+     ],
+     "prompt_number": 5
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 4.6, Page number 119"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\nn = 1;               #lowest energy state\na = 0.1;             #width of box(nm)\nh = 6.625*10**-34;     #planck's constant\ne = 1.602*10**-19;       #conversion factor from J to eV\nm = 9.11*10**-31;        #mass of particle(kg)\n\n#Calculation\na = a*10**-9;        #width of box(m)\nE = (n**2)*(h**2)/(8*m*(a**2));      #energy of particle(J)\nE_eV = E/e;             #energy of particle(eV)\nE_eV=math.ceil(E_eV*10)/10;   #rounding off to 1 decimal\n\n#Result\nprint \"energy of particle is\",E,\"J or\",E_eV,\"eV\" ",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "energy of particle is 6.02231407794e-18 J or 37.6 eV\n"
+      }
+     ],
+     "prompt_number": 6
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 4.7, Page number 120"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\nn = 1;               #lowest energy state\na = 4;             #width of well(nm)\nh = 6.625*10**-34;     #planck's constant\ne = 1.6025*10**-19;       #conversion factor from J to eV\nm = 9.11*10**-31;        #mass of electron(kg)\n\n#Calculation\na = a*10**-9;        #width of box(m)\nE = (n**2)*(h**2)/(8*m*(a**2));      #energy of particle(J)\nE_eV = E/e;             #energy of particle(eV)\nE_eV=math.ceil(E_eV*10**4)/10**4;   #rounding off to 4 decimals\n\n#Result\nprint \"minimum energy of electron is\",E,\"J or\",E_eV,\"eV\" ",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "minimum energy of electron is 3.76394629871e-21 J or 0.0235 eV\n"
+      }
+     ],
+     "prompt_number": 7
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 4.8, Page number 120"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\nn1 = 1;               #lowest energy state\nn2 = 6;               #for 6th excited state\na = 0.1;             #width of box(nm)\nh = 6.625*10**-34;     #planck's constant\ne = 1.602*10**-19;       #conversion factor from J to eV\nm = 9.11*10**-31;        #mass of electron(kg)\n\n#Calculation\na = a*10**-9;        #width of box(m)\nE1 = (n1**2)*(h**2)/(8*m*(a**2));      #energy of electron in ground state(J)\nE6 = (n2**2)*(h**2)/(8*m*(a**2));      #energy of electron in excited state(J)\nE = E6-E1;                          #energy required to excite the electron(J)\nE_eV = E/e;             #energy required to excite the electron(eV)\nE_eV=math.ceil(E_eV*10)/10;   #rounding off to 1 decimal\n\n#Result\nprint \"energy required to excite the electron is\",E,\"J or\",E_eV,\"eV\" \nprint \"answer for energy in eV given in the book is wrong\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "energy required to excite the electron is 2.10780992728e-16 J or 1315.8 eV\nanswer for energy in eV given in the book is wrong\n"
+      }
+     ],
+     "prompt_number": 8
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 4.9, Page number 121"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\nh = 6.625*10**-34;     #planck's constant\nc = 3*10**8;       #velocity of light(m/sec)\nm0 = 9.11*10**-31;        #rest mass of electron(kg)\nphi = 90;              #angle of scattering(degrees)\nx = math.pi/180;       #conversion factor from degrees to radians\n\n#Calculation\nphi = phi*x;           ##angle of scattering(radian)\ndelta_lamda = h*(1-math.cos(phi))/(m0*c);         #change in wavelength(m)\n\n#Result\nprint \"change in wavelength of X-ray photon is\",delta_lamda,\"m\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "change in wavelength of X-ray photon is 2.42407610684e-12 m\n"
+      }
+     ],
+     "prompt_number": 9
+    }
+   ],
+   "metadata": {}
+  }
+ ]
+}
\ No newline at end of file
diff --git a/Engineering_Physics/Chapter5.ipynb b/Engineering_Physics/Chapter5.ipynb
new file mode 100755
index 00000000..ba6e0e69
--- /dev/null
+++ b/Engineering_Physics/Chapter5.ipynb
@@ -0,0 +1,152 @@
+{
+ "metadata": {
+  "name": "Chapter5"
+ },
+ "nbformat": 3,
+ "nbformat_minor": 0,
+ "worksheets": [
+  {
+   "cells": [
+    {
+     "cell_type": "heading",
+     "level": 1,
+     "metadata": {},
+     "source": "5: Crystal Physics"
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 5.1, Page number 149, theoretical"
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 5.2, Page number 150"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\nn = 8;          #number of atoms per cell\na = 5.43*10**-8;       #lattice constant(cm)\nw = 28.1;              #atomic weight(gm)\nN = 6.02*10**23;       #avagadro number\n\n#Calculation\nac = n/(a**3);         #atomic concentration(atoms/cm**3)\nd = ac*w/N;            #density of Si(g/cm**3)\nd=math.ceil(d*10**3)/10**3;   #rounding off to 3 decimals\n\n#Result\nprint \"density of Si is\",d,\"g/cm**3\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "density of Si is 2.333 g/cm**3\n"
+      }
+     ],
+     "prompt_number": 2
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 5.3, Page number 151"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\nfrom __future__ import division\n\n#Variable declaration\na = 5;       #lattice constant(Angstrom)\n\n#Calculation\na = a*10**-10;         #lattice constant(m)\n#to calculate the planar concentration, only equilateral triangular region is considered of length a*math.sqrt(2) and height a*math.sqrt(3/2)\nl = a*math.sqrt(2);           #length of face diagonal(m)\nh = a*math.sqrt(3/2);         #height of triangle(m)\nA = l*h/2;                    #area of shaded portion(m**2)\n#every atom at the corner contributes 1/6 to this area.\nn111 = (3/6)*(1/A);           #planar concentration(atoms/m**2)\n\n#Result\nprint \"surface density of atoms is\",n111,\"atoms/m**2\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "surface density of atoms is 2.30940107676e+18 atoms/m**2\n"
+      }
+     ],
+     "prompt_number": 3
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 5.4, Page number 152"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\na = 4.049;       #lattice constant(Angstrom)\nh = 2;\nk = 2;\nl = 0;           #miller indices of(2 2 0)\n\n#Calculation\nd = a/math.sqrt(h**2+k**2+l**2);        #spacing of planes(Angstrom)\nd=math.ceil(d*10**3)/10**3;   #rounding off to 3 decimals\n\n#Result\nprint \"spacing of planes is\",d,\"Angstrom\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "spacing of planes is 1.432 Angstrom\n"
+      }
+     ],
+     "prompt_number": 4
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 5.5, Page number 152"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\nd110 = 2.03;       #distance between planes(Angstrom)\nh = 1;\nk = 1;\nl = 0;           #miller indices of(1 1 0)\n\n#Calculation\na = d110*math.sqrt(h**2+k**2+l**2);        #size of unit cell(Angstrom)\na=math.ceil(a*10**3)/10**3;   #rounding off to 3 decimals\n\n#Result\nprint \"size of unit cell is\",a,\"Angstrom\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "size of unit cell is 2.871 Angstrom\n"
+      }
+     ],
+     "prompt_number": 5
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 5.6, Page number 152"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\na = 5.64;       #lattice constant(Angstrom)\nh1 = 1;\nk1 = 0;\nl1 = 0;           #miller indices of(1 0 0)\nh2 = 1;\nk2 = 1;\nl2 = 0;           #miller indices of(1 1 0)\nh3 = 1;\nk3 = 1;\nl3 = 1;           #miller indices of(1 1 1)\n\n#Calculation\nd100 = a/math.sqrt(h1**2+k1**2+l1**2);        #spacing of planes[100](Angstrom)\nd110 = a/math.sqrt(h2**2+k2**2+l2**2);        #spacing of planes[110](Angstrom)\nd111 = a/math.sqrt(h3**2+k3**2+l3**2);        #spacing of planes[111](Angstrom)\nd111=math.ceil(d111*10**2)/10**2;   #rounding off to 2 decimals\n\n#Result\nprint \"spacing of plane [100] is\",d100,\"Angstrom\"\nprint \"spacing of plane [110] is\",round(d110),\"Angstrom\"\nprint \"spacing of plane [111] is\",d111,\"Angstrom\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "spacing of plane [100] is 5.64 Angstrom\nspacing of plane [110] is 4.0 Angstrom\nspacing of plane [111] is 3.26 Angstrom\n"
+      }
+     ],
+     "prompt_number": 6
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 5.7, Page number 153"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\nr = 1.605;         #radius of atom(Angstrom)\n\n\n#Calculation\nr = r*10**-10;      #radius of atom(m)\na = 2*r;        #size of unit cell(m)\nc = a*math.sqrt(8/3);\nV = 3*math.sqrt(3)*a**2*c/2;       #volume of unit cell(m**3)\n\n#Result\nprint \"volume of unit cell is\",V,\"m**3\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "volume of unit cell is 1.40330266432e-28 m**3\n"
+      }
+     ],
+     "prompt_number": 7
+    }
+   ],
+   "metadata": {}
+  }
+ ]
+}
\ No newline at end of file
diff --git a/Engineering_Physics/Chapter6.ipynb b/Engineering_Physics/Chapter6.ipynb
new file mode 100755
index 00000000..768ed817
--- /dev/null
+++ b/Engineering_Physics/Chapter6.ipynb
@@ -0,0 +1,356 @@
+{
+ "metadata": {
+  "name": "Chapter6"
+ },
+ "nbformat": 3,
+ "nbformat_minor": 0,
+ "worksheets": [
+  {
+   "cells": [
+    {
+     "cell_type": "heading",
+     "level": 1,
+     "metadata": {},
+     "source": "6: Conducting Materials"
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 6.1, Page number 170"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\nm = 9.1*10**-31;          #mass of electron\nvf = 1*10**6;             #Fermi velocity(m/s)\ne = 1.6*10**-19;          #conversion factor from J to eV\n\n#Calculation\nEF = m*(vf**2)/(2*e);         #Fermi energy(eV)\nEF=math.ceil(EF*10**2)/10**2;   #rounding off to 2 decimals\n\n#Result\nprint \"Fermi energy is\",EF,\"eV\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "Fermi energy is 2.85 eV\n"
+      }
+     ],
+     "prompt_number": 1
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 6.2, Page number 170"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\nEF0 = 7.04;               #Fermi energy at 0K(eV)\nT = 300;                  #temperature(K)\nk = 1.38*10**-23;         #boltzmann constant\ne = 1.6*10**-19;          #conversion factor from J to eV\n\n#Calculation\nEF = EF0*(1-(((math.pi**2)/12)*(k*T/(EF0*e))**2));            #Fermi energy(eV)\nEF=math.ceil(EF*10**5)/10**5;   #rounding off to 5 decimals\n\n#Result\nprint \"Fermi energy is\",EF,\"eV\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "Fermi energy is 7.03993 eV\n"
+      }
+     ],
+     "prompt_number": 2
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 6.3, Page number 171"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\nd = 2.7*10**3;          #density of Al(kg/m**3)\nMat = 27;               #atomic weight of Al\ntow = 10**-14;          #relaxation time(sec)\nNa = 6.022*10**23;       #avagadro constant\na = 3*10**3;             #number of free electrons per atom\ne = 1.6*10**-19;         #charge of electron\nme = 9.1*10**-31;        #mass of electron\n\n#Calculation\nn = d*Na*a/Mat;          #concentration of atoms(per m**3)\nsigma = n*e**2*tow/me;          #conductivity(ohm m)\nsigma = sigma*10**-7;\nsigma=math.ceil(sigma*10**4)/10**4;   #rounding off to 4 decimals\n\n#Result\nprint \"conductivity of Al is\",sigma,\"*10**7 ohm m\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "conductivity of Al is 5.0824 *10**7 ohm m\n"
+      }
+     ],
+     "prompt_number": 3
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 6.4, Page number 171"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\nsigma = 5.87*10**7;         #electrical conductivity(per ohm m)\nK = 390;                    #thermal conductivity(W/mK)\nT = 20;                    #temperature(C)\n\n#Calculation\nT = T+273;                #temperature(K)\nL = K/(sigma*T);          #Lorentz number(W ohm/K**2)\n\n#Result\nprint \"Lorentz number is\",L,\"W ohm/K**2\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "Lorentz number is 2.26756051189e-08 W ohm/K**2\n"
+      }
+     ],
+     "prompt_number": 4
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 6.5, Page number 172"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\nd = 8900;          #density of Cu(kg/m**3)\nMat = 63.5;               #atomic weight of Cu\ntow = 10**-14;          #relaxation time(sec)\nNa = 6.022*10**23;       #avagadro constant\na = 1*10**3;             #number of free electrons per atom\ne = 1.6*10**-19;         #charge of electron\nme = 9.1*10**-31;        #mass of electron\n\n#Calculation\nn = d*Na*a/Mat;          #concentration of atoms(per m**3)\nsigma = n*e**2*tow/me;          #electrical conductivity(ohm m)\nsigma = sigma*10**-7;\nsigma=math.ceil(sigma*10**4)/10**4;   #rounding off to 4 decimals\n\n#Result\nprint \"electrical conductivity is\",sigma,\"*10**7 ohm m\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "electrical conductivity is 2.3745 *10**7 ohm m\n"
+      }
+     ],
+     "prompt_number": 5
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 6.6, Page number 172"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\nrho = 1.54*10**-8;         #resistivity(ohm m)\nEF = 5.5;                  #fermi energy(eV)\nme = 9.1*10**-31;          #mass of electron\nepsilon = 100;\ne = 1.6*10**-19;           #charge of electron\nn = 5.8*10**28;            #concentration of electrons(per m**3)\n\n#Calculation\ntow = me/(rho*n*e**2);        #relaxation time(sec)\nmew = e*tow/me;               #mobility of electrons(m**2/Vs)\nmew = mew*10**3;\nvd = e*tow*epsilon/me;        #drift velocity(m/s)\nvd=math.ceil(vd*10)/10;   #rounding off to 1 decimal\nEF = EF*e;                    #fermi energy((J)\nvF = math.sqrt(2*EF/me);           #fermi velocity(m/s)\nvf = vF*10**-6;\nvf=math.ceil(vf*10**3)/10**3;   #rounding off to 3 decimals\nlamda_m = vF*tow;                  #mean free path(m)\n\n#Result\nprint \"relaxation time of electrons is\",tow,\"sec\"\nprint \"mobility of electrons is\",mew,\"*10**-3 m**2/Vs\"\nprint \"drift velocity of electrons is\",vd,\"m/s\"\nprint \"drift velocity given in the book is wrong\"\nprint \"fermi velocity of electrons is\",vf,\"*10**6 m/s\"\nprint \"mean free path is\",lamda_m,\"m\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "relaxation time of electrons is 3.97972178683e-14 sec\nmobility of electrons is 6.9973130318 *10**-3 m**2/Vs\ndrift velocity of electrons is 0.7 m/s\ndrift velocity given in the book is wrong\nfermi velocity of electrons is 1.391 *10**6 m/s\nmean free path is 5.53462691011e-08 m\n"
+      }
+     ],
+     "prompt_number": 6
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 6.7, Page number 174"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\nrho = 1.72*10**-8;          #electrical resistivity(ohm m)\nL = 2.26*10**-8;            #Lorentz number(ohm W/K**2)\nT = 27;                     #temperature(C)\n\n#Calculation\nT = T+273;                #temperature(K)\nK = L*T/rho;          #thermal conductivity(W/mK)\n\n#Result\nprint \"thermal conductivity is\",int(K),\"W/mK\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "thermal conductivity is 394 W/mK\n"
+      }
+     ],
+     "prompt_number": 7
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 6.8, Page number 174"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\nsigma = 5.87*10**7;         #electrical conductivity(per ohm m)\nK = 390;                    #thermal conductivity(W/mK)\nT = 20;                    #temperature(C)\n\n#Calculation\nT = T+273;                #temperature(K)\nL = K/(sigma*T);          #Lorentz number(W ohm/K**2)\n\n#Result\nprint \"Lorentz number is\",L,\"W ohm/K**2\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "Lorentz number is 2.26756051189e-08 W ohm/K**2\n"
+      }
+     ],
+     "prompt_number": 8
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 6.9, Page number 174"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\nE_EF = 0.01;               #energy(eV)\ne = 1.6*10**-19;           #conversion factor from eV to J\nT = 200;                    #temperature(K)\nk = 1.38*10**-23;           #boltzmann constant(J/K)\n\n#Calculation\nE_EF = E_EF*e;            #energy(J)\nA = E_EF/(k*T);\nFofE = 1/(1+(math.exp(A)));           #value of F(E)\nFofE=math.ceil(FofE*10**2)/10**2;   #rounding off to 2 decimals\n\n#Result\nprint \"value of F(E) is\",FofE",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "value of F(E) is 0.36\n"
+      }
+     ],
+     "prompt_number": 9
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 6.10, Page number 175"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\nlamda = 4*10**-8;     #mean free path(m)\nn = 8.4*10**28;          #density(per m**3)\nvthbar = 1.6*10**6;        #average thermal velocity(m/s)\ne = 1.6*10**-19;         #charge of electron(c)\nm = 9.11*10**-31;        #mass of electron\n\n#Calculation\nsigma = n*e**2*lamda/(m*vthbar);        #electrical conductivity(ohm-1 m-1)\nsigma = sigma*10**-7;\nsigma=math.ceil(sigma*100)/100;   #rounding off to 2 decimals\n\n#Result\nprint \"electrical conductivity is\",sigma,\"*10**7 ohm-1 m-1\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "electrical conductivity is 5.91 *10**7 ohm-1 m-1\n"
+      }
+     ],
+     "prompt_number": 10
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 6.11, Page number 176"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\ntow = 10**-14;         #relaxation time(sec)\nT = 300;               #temperature(K)\nn = 6*10**28;          #electron concentration(per m**3)\ne = 1.6*10**-19;         #charge of electron(c)\nme = 9.1*10**-31;        #mass of electron\nk = 1.38*10**-23;           #boltzmann constant(J/K)\n\n#Calculation\nsigma = n*e**2*tow/me;        #electrical conductivity(ohm-1 m-1)\nsigmaa = sigma*10**-7;\nsigmaa=math.ceil(sigmaa*100)/100;   #rounding off to 2 decimals\nK = 3*n*(k**2)*tow*T/(2*me);           #thermal conductivity(W/mK)\nK=math.ceil(K*10)/10;   #rounding off to 1 decimal\nL = K/(sigma*T);         #Lorentz number(W ohm/K**2)\n\n#Result\nprint \"electrical conductivity is\",sigmaa,\"*10**7 ohm-1 m-1\"\nprint \"thermal conductivity is\",K,\"W/mK\"\nprint \"Lorentz number is\",L,\"W ohm/K**2\"\nprint \"answer for thermal conductivity and Lorentz number given in the book are wrong\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "electrical conductivity is 1.69 *10**7 ohm-1 m-1\nthermal conductivity is 56.6 W/mK\nLorentz number is 1.11775173611e-08 W ohm/K**2\nanswer for thermal conductivity and Lorentz number given in the book are wrong\n"
+      }
+     ],
+     "prompt_number": 11
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 6.12, Page number 177"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\nn = 5.8*10**28;          #electron concentration(per m**3)\ne = 1.6*10**-19;         #charge of electron(c)\nm = 9.1*10**-31;        #mass of electron\nrho = 1.54*10**-8;       #resistivity of metal(ohm m)\n\n#Calculation\ntow = m/(n*rho*e**2);         #relaxation time(sec)\n\n#Result\nprint \"relaxation time is\",tow,\"sec\"\nprint \"answer given in the book is wrong\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "relaxation time is 3.97972178683e-14 sec\nanswer given in the book is wrong\n"
+      }
+     ],
+     "prompt_number": 12
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 6.13, Page number 177"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\nrho = 1.54*10**-8;         #resistivity(ohm m)\nE = 1;                  #electric field(V/cm)\nme = 9.1*10**-31;          #mass of electron\ne = 1.6*10**-19;           #charge of electron\nn = 5.8*10**28;            #concentration of electrons(per m**3)\n\n#Calculation\nE = E*10**2;            #electric field(V/m)\ntow = me/(rho*n*e**2);        #relaxation time(sec)\nvd = e*E*tow/me;        #drift velocity(m/s)\nvd=math.ceil(vd*10)/10;   #rounding off to 1 decimal\nmew = vd/E;               #mobility of electrons(m**2/Vs)\nmew = mew*10**2;\n\n#Result\nprint \"relaxation time of electrons is\",tow,\"sec\"\nprint \"drift velocity of electrons is\",vd,\"m/s\"\nprint \"mobility of electrons is\",mew,\"*10**-2 m**2/Vs\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "relaxation time of electrons is 3.97972178683e-14 sec\ndrift velocity of electrons is 0.7 m/s\nmobility of electrons is 0.7 *10**-2 m**2/Vs\n"
+      }
+     ],
+     "prompt_number": 13
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 6.14, Page number 178"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\nT = 300;                   #temperature(K)\nl = 2;                     #length of wire(m)\nR = 0.02;                  #resistance(ohm)\nI = 15;                    #current(amp)\nmew = 4.3*10**-3;          #mobility(m**2/Vs)\n\n#Calculation\nV = I*R;                   #voltage drop(V)\nE = V/l;                   #electric field(V/m)\nvd = mew*E;                #drift velocity(m/s)\nvd = vd*10**3;\nvd=math.ceil(vd*100)/100;   #rounding off to 2 decimals\n\n#Result\nprint \"drift velocity of electrons is\",vd,\"*10**-3 m/s\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "drift velocity of electrons is 0.65 *10**-3 m/s\n"
+      }
+     ],
+     "prompt_number": 14
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 6.15, Page number 179"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\nvf = 0.86*10**6;          #fermi velocity(m/s)\nm = 9.1*10**-31;          #mass of electron(kg)\ne = 1.6*10**-19;          #charge of electron(C)\nk = 1.38*10**-23;         #boltzmann constant\n\n#Calculation\nEF = m*vf**2/(2*e);       #fermi energy(eV)\nEF=math.ceil(EF*100)/100;   #rounding off to 2 decimals\nTF = EF*e/k;                  #fermi temperature(K)\n\n#Result\nprint \"Fermi energy is\",EF,\"eV\"\nprint \"Fermi temperature is\",int(TF),\"K\"\nprint \"answer for fermi temperature given in the book is wrong due to rounding off the value of EF\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "Fermi energy is 2.11 eV\nFermi temperature is 24463 K\nanswer for fermi temperature given in the book is wrong due to rounding off the value of EF\n"
+      }
+     ],
+     "prompt_number": 15
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 6.16, Page number 179"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\nTF = 2460;            #fermi temperature(K)\nm = 9.11*10**-31;          #mass of electron(kg)\nk = 1.38*10**-23;         #boltzmann constant\n\n#Calculation\nvF = math.sqrt(2*k*TF/m);          #fermi velocity(m/s)\nvF = vF*10**-5;\nvF=math.ceil(vF*10**3)/10**3;   #rounding off to 3 decimals\n\n#Result\nprint \"Fermi velocity is\",vF,\"*10**5 m/s\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "Fermi velocity is 2.731 *10**5 m/s\n"
+      }
+     ],
+     "prompt_number": 16
+    }
+   ],
+   "metadata": {}
+  }
+ ]
+}
\ No newline at end of file
diff --git a/Engineering_Physics/Chapter7.ipynb b/Engineering_Physics/Chapter7.ipynb
new file mode 100755
index 00000000..d6a7ab3d
--- /dev/null
+++ b/Engineering_Physics/Chapter7.ipynb
@@ -0,0 +1,468 @@
+{
+ "metadata": {
+  "name": "Chapter7",
+  "signature": "sha256:043709ddd748250fcd3232cc251c6d71d665f281189e172a4c8d9b59233bdcee"
+ },
+ "nbformat": 3,
+ "nbformat_minor": 0,
+ "worksheets": [
+  {
+   "cells": [
+    {
+     "cell_type": "heading",
+     "level": 1,
+     "metadata": {},
+     "source": "7: Semiconducting Materials"
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 7.1, Page number 208"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\nme = 9.11*10**-31;          #mass of electron(kg)\nepsilon_r = 13.2;  \nepsilon0 = 8.85*10**-12;\nh = 6.63*10**-34;\ne = 1.6*10**-19;          #charge of electron(C)\n\n#Calculation\nm_nc = 0.067*me;\nE = m_nc*e**4/(8*(epsilon0*epsilon_r*h)**2);       #energy(J)\nE = E/e;                #energy(eV)\nE = math.ceil(E*10**5)/10**5;   #rounding off to 5 decimals\nE_meV = E*10**3;        #energy(meV)\n\n#Result\nprint \"donor binding energy is\",E,\"eV or\",E_meV,\"meV\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "donor binding energy is 0.00521 eV or 5.21 meV\n"
+      }
+     ],
+     "prompt_number": 1
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 7.2, Page number 208"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\nimport numpy as np\n\n#Variable declaration\nNd = 10**16;         #donor concentration(atoms/cm**3)\nni = 1.5*10**10;        #concentration(per cm**3)\nT = 300;                #temperature(K)\nkT = 0.0259;\n\n#Calculation\nn0 = Nd;           #for Nd>>ni, assume n0=Nd\np0 = ni**2/n0;        #equilibrium hole concentration(per cm**3)\np0 = p0*10**-4;\nEF_Ei = kT*np.log(n0/ni);\nEF_Ei = math.ceil(EF_Ei*10**4)/10**4;   #rounding off to 4 decimals\n\n\n#Result\nprint \"equilibrium hole concentration is\",p0,\"*10**4 per cm**3\"\nprint \"value of EF-Ei is\",EF_Ei,\"eV\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "equilibrium hole concentration is 2.25 *10**4 per cm**3\nvalue of EF-Ei is 0.3474 eV\n"
+      }
+     ],
+     "prompt_number": 2
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 7.3, Page number 209"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\ne = 1.6*10**-19;          #charge of electron(C)\nNd = 10**14;              #donor density(atoms/cm**3)\nmew_n = 3900;\n\n#Calculation\nn = Nd;\nsigma = n*e*mew_n;        #conductivity(ohm-1 cm-1)\nrho = 1/sigma;            #resistivity(ohm cm)\nrho = math.ceil(rho*100)/100;   #rounding off to 2 decimals\n\n\n#Result\nprint \"resistivity of sample is\",rho,\"ohm cm\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "resistivity of sample is 16.03 ohm cm\n"
+      }
+     ],
+     "prompt_number": 3
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 7.4, Page number 209"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\ne = 1.6*10**-19;          #charge of electron(C)\nn0 = 5*10**16;              #donor density(atoms/cm**3)\nmew_0 = 800;\nIx = 2;             #current(mA)\nBz = 5*10**-5;\nd = 200;            #thickness(micrometre)\n\n#Calculation\nIx = Ix*10**-3;          #current(A)\nd = d*10**-4;            #thickness(m)\nsigma = e*n0*mew_0;        #conductivity(ohm-1 cm-1)\nrho = 1/sigma;            #resistivity(ohm cm)\nrho = math.ceil(rho*10**4)/10**4;   #rounding off to 4 decimals\nRH = -1/(e*n0);          #Hall coefficient(cm**3/C)\nVH = Ix*Bz*RH/d;         #Hall voltage(V)\nVH = VH*10**5;\n\n\n#Result\nprint \"resistivity of sample is\",rho,\"ohm cm\"\nprint \"Hall coefficient is\",RH,\"cm**3/C\"\nprint \"Hall voltage is\",VH,\"*10**-5 V\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "resistivity of sample is 0.1563 ohm cm\nHall coefficient is -125.0 cm**3/C\nHall voltage is -62.5 *10**-5 V\n"
+      }
+     ],
+     "prompt_number": 4
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 7.5, Page number 210"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\nfrom __future__ import division\n\n#Variable declaration\nT = 300;          #temperature(K)\nmew_n = 0.4;      #electron mobility(m**2/Vs)\nmew_p = 0.2;      #hole mobility(m**2/Vs)\nEg = 0.7;         #band gap(eV)\nme = 9.11*10**-31;       #mass of electron(kg)\nk = 1.38*10**-23;        #boltzmann constant\nT = 300;                 #temperature(K)\nh = 6.625*10**-34;\nkT = 0.0259;\ne = 1.6*10**-19;          #charge of electron(C)\n\n#Calculation\nmn_star = 0.55*me;           #electron effective mass(kg)\nmp_star = 0.37*me;           #hole effective mass(kg)\na = (2*math.pi*k*T/(h**2))**(3/2);\nb = (mn_star*mp_star)**(3/4);\nc = math.exp(-Eg/(2*kT));\nni = 2*a*b*c;     #intrinsic concentration(per m**3)\nsigma = ni*e*(mew_n+mew_p);               #intrinsic conductivity(per ohm m)\nsigma = math.ceil(sigma*10**4)/10**4;   #rounding off to 4 decimals\nrho = 1/sigma;                            #intrinsic resistivity(ohm m)\nrho = math.ceil(rho*10**4)/10**4;   #rounding off to 4 decimals\n\n#Result\nprint \"intrinsic concentration is\",ni,\"per m**3\"\nprint \"intrinsic conductivity is\",sigma,\"per ohm m\"\nprint \"intrinsic resistivity is\",rho,\"ohm m\"\nprint \"answers given in the book are wrong\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "intrinsic concentration is 1.02825111151e+19 per m**3\nintrinsic conductivity is 0.9872 per ohm m\nintrinsic resistivity is 1.013 ohm m\nanswers given in the book are wrong\n"
+      }
+     ],
+     "prompt_number": 5
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 7.6, Page number 211"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\nimport numpy as np\nfrom __future__ import division\n\n#Variable declaration\nNd = 10**16;           #donor concentration(per cm**3)\nni = 1.45*10**10;         #concentration(per cm**3)\nkT = 0.0259;\n\n#Calculation\n#ni = Nc*math.exp(-(Ec-Ei)/kT)\n#Nd = Nc*(math.exp(-(Ec-Efd)/kT)\n#dividing Nd/ni we get \nEFd_Ei = kT*np.log(Nd/ni);\nEFd_Ei = math.ceil(EFd_Ei*10**4)/10**4;   #rounding off to 4 decimals\n\n#Result\nprint \"Fermi energy is\",EFd_Ei,\"eV\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "Fermi energy is 0.3482 eV\n"
+      }
+     ],
+     "prompt_number": 6
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 7.7, Page number 211, theoretical"
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 7.8, Page number 212"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\nimport numpy as np\nfrom __future__ import division\n\n#Variable declaration\nT = 300;          #temperature(K)\nmew_n = 0.36;      #electron mobility(m**2/Vs)\nmew_p = 0.17;      #hole mobility(m**2/Vs)\nrho = 2.12;         #resistivity(ohm m)\nme = 9.11*10**-31;       #mass of electron(kg)\nkT = 0.0259;\nh = 6.625*10**-34;\nk = 1.38*10**-23;        #boltzmann constant\ne = 1.6*10**-19;          #charge of electron(C)\n\n#Calculation\nmn_star = 0.55*me;           #electron effective mass(kg)\nmp_star = 0.37*me;           #hole effective mass(kg)\nsigma = 1/rho;               #conductivity(per ohm m)\nsigma = math.ceil(sigma*10**3)/10**3;   #rounding off to 3 decimals\nni = sigma/(e*(mew_n+mew_p));          #concentration of electrons(per m**3)\na = (2*math.pi*kT/(h**2))**(3/2);\nNc = 2*a*(mn_star**(3/2)); \nNv = 2*a*(mp_star**(3/2)); \nb = (Nc*Nv)**(1/2);\nEg = 2*kT*np.log(b/ni);\n\n#Result\nprint \"forbidden energy gap is\",Eg,\"eV\"\nprint \"answer given in the book is wrong\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "forbidden energy gap is 4.09465494989 eV\nanswer given in the book is wrong\n"
+      }
+     ],
+     "prompt_number": 8
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 7.9, Page number 213"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\nni = 2.4*10**19;       #concentration(per m**3)\nmew_n = 0.39;      #electron mobility(m**2/Vs)\nmew_p = 0.19;      #hole mobility(m**2/Vs)\ne = 1.6*10**-19;          #charge of electron(C)\n\n#Calculation\nsigma = ni*e*(mew_n+mew_p);         #conductivity(per ohm m)\nsigma = math.ceil(sigma*10**3)/10**3;   #rounding off to 3 decimals\n\n#Result\nprint \"conductivity of sample is\",sigma,\"ohm-1 m-1\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "conductivity of sample is 2.228 ohm-1 m-1\n"
+      }
+     ],
+     "prompt_number": 9
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 7.10, Page number 214"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\nfrom __future__ import division\n\n#Variable declaration\nEc = 0.3;          #initial position(eV)\nT1 = 300;           #initial temperature(K)\nT2 = 330;           #increased temperature\n\n#Calculation\n#Ec/T1 = Ec_EF330/T2\nEc_EF330 = Ec*T2/T1;        #new position of Fermi level(eV)\n\n#Result\nprint \"new position of Fermi level is\",Ec_EF330,\"eV\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "new position of Fermi level is 0.33 eV\n"
+      }
+     ],
+     "prompt_number": 10
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 7.11, Page number 214"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\nfrom __future__ import division\n\n#Variable declaration\nk = 1.38*10**-23;         #boltzmann constant\nT = 300;           #temperature(K)\nme = 9.1*10**-31;        #mass of electron(kg)\nh = 6.63*10**-34;        #planck's constant\nEc_Ev = 1.1;             #energy gap(eV)\ne = 1.6*10**-19;         #charge of electron(C)\n\n#Calculation\nme_star = 0.31*me;\nA = (2*math.pi*k*T*me_star/(h**2))**(3/2);\nB = math.exp(-(Ec_Ev*e)/(2*k*T));\nni = A*B;                  #concentration in conduction band(per m**3)\n\n#Result\nprint \"intrinsic electron concentration is\",ni,\"per m**3\"\nprint \"answer given in the book is wrong\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "intrinsic electron concentration is 1.26605935487e+15 per m**3\nanswer given in the book is wrong\n"
+      }
+     ],
+     "prompt_number": 11
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 7.12, Page number 214"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\nRH = 0.55*10**-10;          #Hall coefficient(m**3/As)\nsigma = 5.9*10**7;          #conductivity(ohm-1 m-1)\n\n#Calculation\nmew = RH*sigma;              #drift mobility(m**2/Vs)\nmew = mew*10**3;\nmew = math.ceil(mew*10**2)/10**2;   #rounding off to 2 decimals\n\n#Result\nprint \"drift mobility of electrons is\",mew,\"*10**-3 m**2/Vs\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "drift mobility of electrons is 3.25 *10**-3 m**2/Vs\n"
+      }
+     ],
+     "prompt_number": 12
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 7.13, Page number 215"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\nfrom __future__ import division\n\n#Variable declaration\nA = 6.022*10**23;           #avagadro constant\nd = 8.96*10**-9;            #density(kg/m**3)\nn = 9.932*10**14;           #no. of free electrons per atom\nsigma = 5.9*10**7;          #conductivity(ohm-1 m-1)\ne = 1.6*10**-19;            #electron charge(C)\nmew = 3.2*10**-3;           #drift mobility(m**2/Vs)\nw = 63.5;                   #atomic weight of Cu(kg)\n\n#Calculation\nni = sigma/(mew*e);         #conductivity(per m**3)\nN = A*d*n/w;                #concentration of free electrons in pure Cu\nAN = ni/N;                  #average number of electrons contributed per Cu atom\n\n#Result\nprint \"concentration of free electrons in pure Cu is\",N,\"per m**3\"\nprint \"average number of electrons contributed per Cu atom is\",int(AN)",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "concentration of free electrons in pure Cu is 8.43940339906e+28 per m**3\naverage number of electrons contributed per Cu atom is 1\n"
+      }
+     ],
+     "prompt_number": 13
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 7.14, Page number 215"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\nfrom __future__ import division\n\n#Variable declaration\nRH = 3.66*10**-11;          #hall coefficient(m**3/As)\ne = 1.6*10**-19;            #electron charge(C)\nsigma = 112*10**7;          #conductivity(ohm-1 m-1)\n\n#Calculation\nn = 1/(e*RH);               #charge carrier density(per m**3)\nmew_n = sigma/(n*e);        #electron mobility(m**2/As)\nmew_n = math.ceil(mew_n*10**3)/10**3;   #rounding off to 3 decimals\n\n#Result\nprint \"charge carrier density is\",n,\"per m**3\"\nprint \"electron mobility is\",mew_n,\"m**2/As\"\nprint \"answers given in the book are wrong\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "charge carrier density is 1.70765027322e+29 per m**3\nelectron mobility is 0.041 m**2/As\nanswers given in the book are wrong\n"
+      }
+     ],
+     "prompt_number": 14
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 7.15, Page number 216"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\nfrom __future__ import division\n\n#Variable declaration\ne = 1.6*10**-19;            #electron charge(C)\nB = 1.5;                    #magnetic field(T)\nI = 50;                     #current(Amp)\nn = 8.4*10**28;             #free electron concentration(per m**3)\nd = 0.2;                    #thickness of slab(cm)\n\n#Calculation\nd = d*10**-2;               #thickness of slab(m)\nVH = B*I/(n*e*d);           #hall voltage(V)\n\n#Result\nprint \"magnitude of Hall voltage is\",VH,\"V\"\nprint \"answer given in the book is wrong\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "magnitude of Hall voltage is 2.79017857143e-06 V\nanswer given in the book is wrong\n"
+      }
+     ],
+     "prompt_number": 15
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 7.16, Page number 216"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\nfrom __future__ import division\n\n#Variable declaration\ne = 1.6*10**-19;            #electron charge(C)\nn = 2.5*10**19;             #free electron concentration(per m**3)\nmew_n = 0.39;               #electron mobility(m**2/Vs)\nmew_p = 0.19;               #hole mobility(m**2/Vs)\nL = 1;                      #length(cm)\nw = 1;                      #width(mm)\nt = 1;                      #thickness(mm)\n\n#Calculation\nL = L*10**-2;               #length(m)\nw = w*10**-3;               #width(m)\nt = t*10**-3;               #thickness(m)\nA = w*t;                    #area(m**2)\nsigma = n*e*(mew_n+mew_p);         #conductivity(ohm-1 m-1)\nR = L/(sigma*A);                   #resistance(ohm)\n\n#Result\nprint \"resistance of intrinsic Ge rod is\",int(R),\"ohm\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "resistance of intrinsic Ge rod is 4310 ohm\n"
+      }
+     ],
+     "prompt_number": 16
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 7.17, Page number 216"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\nimport numpy as np\nfrom __future__ import division\n\n#Variable declaration\ne = 1.6*10**-19;            #electron charge(C)\nEg = 1.12;                  #band gap(eV)\nme = 1;\nmn_star = 0.12*me;               #electron mobility(m**2/Vs)\nmp_star = 0.28*me;               #hole mobility(m**2/Vs)\nk = 1.38*10**-23;                #boltzmann constant\nT = 300;                         #temperature\n\n#Calculation\na = mp_star/mn_star;\nEF = (Eg/2)+((3*k*T/(4*e))*np.log(a));\nEF = math.ceil(EF*10**3)/10**3;   #rounding off to 3 decimals\n\n#Result\nprint \"position of Fermi level is\",EF,\"eV\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "position of Fermi level is 0.577 eV\n"
+      }
+     ],
+     "prompt_number": 17
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 7.18, Page number 217"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\ne = 1.6*10**-19;            #electron charge(C)\nni = 1.5*10**16;            #intrinsic carrier density(per m**3)\nmew_n = 0.13;               #electron mobility(m**2/Vs)\nmew_p = 0.05;               #hole mobility(m**2/Vs)\n\n#Calculation\nsigma = ni*e*(mew_n+mew_p);        #electrical conductivity\nsigma = sigma*10**4;\n\n#Result\nprint \"electrical conductivity is\",sigma,\"*10**-4 ohm-1 m-1\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "electrical conductivity is 4.32 *10**-4 ohm-1 m-1\n"
+      }
+     ],
+     "prompt_number": 18
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 7.19, Page number 217"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\nfrom __future__ import division\n\n#Variable declaration\ne = 1.6*10**-19;            #electron charge(C)\nni = 2.15*10**-13;            #intrinsic carrier density(per cm**3)\nmew_n = 3900;               #electron mobility(cm**2/Vs)\nmew_p = 1900;               #hole mobility(cm**2/Vs)\n\n#Calculation\nsigmai = ni*e*(mew_n+mew_p);        #electrical conductivity(ohm-1 cm-1)\nrhoi = 1/sigmai;                    #intrinsic resistivity(ohm cm)\n\n#Result\nprint \"intrinsic resistivity is\",rhoi,\"ohm cm\"\nprint \"answer given in the book is wrong\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "intrinsic resistivity is 5.01202886929e+27 ohm cm\nanswer given in the book is wrong\n"
+      }
+     ],
+     "prompt_number": 19
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 7.20, Page number 217"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\ne = 1.6*10**-19;            #electron charge(C)\nni = 2.1*10**19;            #intrinsic carrier density(per m**3)\nmew_n = 0.4;               #electron mobility(m**2/Vs)\nmew_p = 0.2;               #hole mobility(m**2/Vs)\n\n#Calculation\nsigma = ni*e*(mew_n+mew_p);        #electrical conductivity\n\n#Result\nprint \"intrinsic resistivity is\",sigma,\"ohm-1 m-1\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "intrinsic resistivity is 2.016 ohm-1 m-1\n"
+      }
+     ],
+     "prompt_number": 20
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 7.21, Page number 218"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\ne = 1.6*10**-19;            #electron charge(C)\nV = 1.35;                   #voltage supply(V)\nI = 5;               #current(mA)\nb = 5;               #breadth(mm)\nd = 1;               #thickness(mm)\nL = 1;               #length(cm)\nH = 0.45;            #magnetic field(Wb/m**2)\nVy =20;              #Hall voltage(mV)\n\n#Calculation\nVy = Vy*10**-3;       #Hall voltage(V)\nL = L*10**-2;         #length(m)\nd = d*10**-3;         #thickness(m)\nb = b*10**-3;         #breadth(m)\nI = I*10**-3;         #current(A)\nR = V/I;              #resistance(ohm)\nA = b*d;              #area(m**2)\nrho = R*A/L;          #resistivity(ohm m)\nEy = Vy/d;            #Hall field(V/m)\nJx = I/A;           \na = Ey/(H*Jx);         #current density(m**3/C).Here a is 1/ne \nRH = a;               #Hall coefficient(m**3/C)\nRH = math.ceil(RH*10**4)/10**4;   #rounding off to 4 decimals\nmew_n = RH/rho;       #electron mobility(m**2/Vs)\nmew_n = math.ceil(mew_n*10**2)/10**2;   #rounding off to 2 decimals\n\n#Result\nprint \"Hall coefficient is\",RH,\"m**3/C\"\nprint \"electron mobility is\",mew_n,\"m**2/Vs\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "Hall coefficient is 0.0445 m**3/C\nelectron mobility is 0.33 m**2/Vs\n"
+      }
+     ],
+     "prompt_number": 21
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 7.22, Page number 219"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\ne = 1.6*10**-19;            #electron charge(C)\nIx = 200;               #current(A)\nBz = 1.5;               #magnetic field(Wb/m**2)\np = 8.4*10**28;         #electron concentration(per m**3)\nd = 1;               #thickness(mm)\n\n#Calculation\nd = d*10**-3;         #thickness(m)\nVH = Ix*Bz/(e*p*d);         #Hall potential(V)\nVH = VH*10**6;              #Hall potential(micro V)\n\n#Result\nprint \"Hall potential is\",int(VH),\"micro V\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "Hall potential is 22 micro V\n"
+      }
+     ],
+     "prompt_number": 22
+    }
+   ],
+   "metadata": {}
+  }
+ ]
+}
\ No newline at end of file
diff --git a/Engineering_Physics/Chapter8.ipynb b/Engineering_Physics/Chapter8.ipynb
new file mode 100755
index 00000000..54d83b1d
--- /dev/null
+++ b/Engineering_Physics/Chapter8.ipynb
@@ -0,0 +1,125 @@
+{
+ "metadata": {
+  "name": "Chapter8"
+ },
+ "nbformat": 3,
+ "nbformat_minor": 0,
+ "worksheets": [
+  {
+   "cells": [
+    {
+     "cell_type": "heading",
+     "level": 1,
+     "metadata": {},
+     "source": "8: Magnetic Materials"
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 8.1, Page number 238"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\nI = 12;          #current(Ampere)\nA = 7.5*10**-4       #area of loop(m**2)\n\n#Calculation\nM = I*A;         #magnetic moment(Am**2)\nM = M*10**3;\n\n#Result\nprint \"magnetic moment is\",M,\"*10**-3 Am**2\"\nprint \"magnetic moment is in opposite direction from the observer\"\nprint \"M is perpendicular to the plane\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "magnetic moment is 9.0 *10**-3 Am**2\nmagnetic moment is in opposite direction from the observer\nM is perpendicular to the plane\n"
+      }
+     ],
+     "prompt_number": 1
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 8.2, Page number 238"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\nr = 0.5;         #radius of orbit(Angstrom)\ne = 1.6*10**-19;       #charge of electron(C)\nnew = 10**16;          #frequency(rps)\n\n#Calculation\nr = r*10**-10;         #radius of orbit(m)\nI = e*new;             #current(Ampere)\nA = math.pi*r**2;      #area enclosed(m**2)\nM = I*A;               #magnetic moment(Am**2)\n\n#Result\nprint \"magnetic moment is\",M,\"Am**2\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "magnetic moment is 1.25663706144e-23 Am**2\n"
+      }
+     ],
+     "prompt_number": 2
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 8.3, Page number 239"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\nmew_r = 5000;       #relative permeability\n\n#Calculation\nchi_m = mew_r-1;       #magnetic susceptibility\n\n#Result\nprint \"magnetic susceptibility is\",chi_m",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "magnetic susceptibility is 4999\n"
+      }
+     ],
+     "prompt_number": 3
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 8.4, Page number 239"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\nH = 1800;       #magnetic field(A/m)\nphi = 3*10**-5;         #magnetic flux(Wb)\nA = 0.2;           #cross sectional area(cm**2)\n\n#Calculation\nA = A*10**-4;      #cross sectional area(m**2)\nB = phi/A;         #magnetic flux density(Wb/m**2)\nmew = B/H;         #permeability(H/m)\nmew = mew*10**4;\nmew=math.ceil(mew*100)/100;   #rounding off to 2 decimals\n\n#Result\nprint \"permeability is\",mew,\"*10**-4 H/m\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "permeability is 8.34 *10**-4 H/m\n"
+      }
+     ],
+     "prompt_number": 4
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 8.5, Page number 239"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\nB = 0.65;      #magnetic induction(Wb/m**2)\nrho = 8906;       #density(kg/m**3)\nM = 58.7;         #atomic weight\nmew0 = 4*math.pi*10**-7;\nmb = 9.27*10**-24;\nNa = 6.023*10**26;      #avagadro constant\n\n#Calculation\nN = rho*Na/M;         #number of atoms per unit volume(atoms/m**3)\nmew_r = B/(N*mew0);         #relative permeability(A/m**2)\nM = mew_r/mb;               #magnetic moment in mew_B \nM=math.ceil(M*10**3)/10**3;   #rounding off to 3 decimals\n\n#Result\nprint \"magnetic moment is\",M,\"mew_B\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "magnetic moment is 0.611 mew_B\n"
+      }
+     ],
+     "prompt_number": 5
+    }
+   ],
+   "metadata": {}
+  }
+ ]
+}
\ No newline at end of file
diff --git a/Engineering_Physics/Chapter9.ipynb b/Engineering_Physics/Chapter9.ipynb
new file mode 100755
index 00000000..ff53dd34
--- /dev/null
+++ b/Engineering_Physics/Chapter9.ipynb
@@ -0,0 +1,62 @@
+{
+ "metadata": {
+  "name": "Chapter9"
+ },
+ "nbformat": 3,
+ "nbformat_minor": 0,
+ "worksheets": [
+  {
+   "cells": [
+    {
+     "cell_type": "heading",
+     "level": 1,
+     "metadata": {},
+     "source": "9: Superconducting Materials"
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 9.1, Page number 255"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\nH0 = 6.5*10**4;         #magnetic field intensity(A/m)\nT = 4.2;                #temperature(K)\nTc = 7.18;              #critical temperature(K)\n\n#Calculation\nHc = H0*(1-((T**2)/(Tc**2)));        #critical magnetic field intensity(A/m)\nHc = Hc*10**-4;\nHc=math.ceil(Hc*10**3)/10**3;   #rounding off to 3 decimals\n\n#Result\nprint \"critical magnetic field intensity is\",Hc,\"*10**4 A/m\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "critical magnetic field intensity is 4.276 *10**4 A/m\n"
+      }
+     ],
+     "prompt_number": 1
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example number 9.2, Page number 255"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#importing modules\nimport math\n\n#Variable declaration\nTc1 = 4.185;                #critical temperature for M1(K)\nTc2 = 4.133;                #critical temperature for M2(K)\nM1 = 199.5;                 #isotopic mass\nalpha = 0.5;\n\n#Calculation\nA = math.pow(M1,alpha)*Tc1/Tc2;\nM2 = math.pow(A,1/alpha);       #isotopic mass\nM2=math.ceil(M2*10**3)/10**3;   #rounding off to 3 decimals\n\n#Result\nprint \"isotopic mass is\",M2\nprint \"answer given in the book is wrong\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "isotopic mass is 204.552\nanswer given in the book is wrong\n"
+      }
+     ],
+     "prompt_number": 2
+    }
+   ],
+   "metadata": {}
+  }
+ ]
+}
\ No newline at end of file
diff --git a/Engineering_Physics/README.txt b/Engineering_Physics/README.txt
new file mode 100755
index 00000000..bd7c4bfa
--- /dev/null
+++ b/Engineering_Physics/README.txt
@@ -0,0 +1,10 @@
+Contributed By: KRISHNA CHAITANYA
+Course: btech
+College/Institute/Organization: JNTUH
+Department/Designation: Computer Science
+Book Title: Engineering Physics
+Author: D. K. Bhattacharya & A. Bhaskaran
+Publisher: Oxford University Press, New Delhi
+Year of publication: 2013
+Isbn: 9780198065425
+Edition: 1
\ No newline at end of file
diff --git a/Engineering_Physics/screenshots/Untitled1.png b/Engineering_Physics/screenshots/Untitled1.png
new file mode 100755
index 00000000..2584f5af
--- /dev/null
+++ b/Engineering_Physics/screenshots/Untitled1.png
diff --git a/Engineering_Physics/screenshots/Untitled1_1.png b/Engineering_Physics/screenshots/Untitled1_1.png
new file mode 100755
index 00000000..6c937ec4
--- /dev/null
+++ b/Engineering_Physics/screenshots/Untitled1_1.png
diff --git a/Engineering_Physics/screenshots/Untitled2.png b/Engineering_Physics/screenshots/Untitled2.png
new file mode 100755
index 00000000..7461d551
--- /dev/null
+++ b/Engineering_Physics/screenshots/Untitled2.png
diff --git a/Engineering_Physics/screenshots/Untitled2_1.png b/Engineering_Physics/screenshots/Untitled2_1.png
new file mode 100755
index 00000000..a47a6ec9
--- /dev/null
+++ b/Engineering_Physics/screenshots/Untitled2_1.png
diff --git a/Engineering_Physics/screenshots/Untitled3.png b/Engineering_Physics/screenshots/Untitled3.png
new file mode 100755
index 00000000..492ad660
--- /dev/null
+++ b/Engineering_Physics/screenshots/Untitled3.png
diff --git a/Engineering_Physics/screenshots/Untitled3_1.png b/Engineering_Physics/screenshots/Untitled3_1.png
new file mode 100755
index 00000000..cdbc1a6f
--- /dev/null
+++ b/Engineering_Physics/screenshots/Untitled3_1.png
diff --git a/Surveying_Volume_3/Chapter1.ipynb b/Surveying_Volume_3/Chapter1.ipynb
new file mode 100755
index 00000000..015050ae
--- /dev/null
+++ b/Surveying_Volume_3/Chapter1.ipynb
@@ -0,0 +1,83 @@
+{
+ "metadata": {
+  "name": "S3-C1"
+ },
+ "nbformat": 3,
+ "nbformat_minor": 0,
+ "worksheets": [
+  {
+   "cells": [
+    {
+     "cell_type": "heading",
+     "level": 1,
+     "metadata": {},
+     "source": "Electronic Distance Measurement"
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 1.1,Page 22"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nT=273+25.0#temperature \np=752.0;#pressure mm Hg\nNo=294.0e-6;\nns=1.000284;\nD1=1438.254;#recorded distance in m\nh=263.42-243.25;#height difference in m\nR=6370e3;#radius of earth in m\n\n#calculation\nn=1+No*(273/T)*(p/760);\nD=D1*ns/n;\ncg=-h**2/2/D;\nHm=263.42/2+243.25/2;\nD=D+cg;\nch=-D*Hm/R\nEL=D+ch;\n\n#result\nprint \"equivalent length in m\",round(EL,3)",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "equivalent length in m 1438.081\n"
+      }
+     ],
+     "prompt_number": 2
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 1.2,Page 22"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nT=273+18.8;#temperature\np=713;\ne=3;\nc=299792.5e3;#speed of light in km/s\nf=11e6;#frequency in Hz\n\n#calculation\nn=1+(103.49/T*(p-e)+86.26/T*(1+5748.0/T)*e)/1e6;\nV=c/n;\nl=V/f;\n\n#result\nprint \"wavelenght of light in m\",round(l,3)",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "27.247 wavelenght of light in m\n"
+      }
+     ],
+     "prompt_number": 4
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 1.3,Page 23"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nT=273.0+30.0;#temperature\nl=0.85;#wavelength in m\np=752.4;\nc=299792.5e3;#speed of light in km/s\nf=24e6;#frequency in Hz\n\n#calculation\nno=1+(287.604+4.8864/l**2+0.068/l**4)/1e6;\nns=1+(no-1)*273/T*p/760;\nV=c/ns;\nl=V/f;\n\n#result\nprint \"wavelength of light in m\",round(l,3)",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "wavelenght of light in m 12.488\n"
+      }
+     ],
+     "prompt_number": 1
+    }
+   ],
+   "metadata": {}
+  }
+ ]
+}
\ No newline at end of file
diff --git a/Surveying_Volume_3/Chapter3.ipynb b/Surveying_Volume_3/Chapter3.ipynb
new file mode 100755
index 00000000..4c4c37ac
--- /dev/null
+++ b/Surveying_Volume_3/Chapter3.ipynb
@@ -0,0 +1,104 @@
+{
+ "metadata": {
+  "name": "S3-C3"
+ },
+ "nbformat": 3,
+ "nbformat_minor": 0,
+ "worksheets": [
+  {
+   "cells": [
+    {
+     "cell_type": "heading",
+     "level": 1,
+     "metadata": {},
+     "source": "Trilateration"
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 3.1,Page 47"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,tan,sqrt,sin,cos\nAB=25145.32;\nR=6370.0e3;#radius of earth\nha=325.14;\n\n#calculation\ntheta=AB*cos(3+9.0/60+40.0/3600)/R;\nAB_dash=AB/sin(pi/2+theta/2)*sin(pi/2-theta/2-(3+9.0/60+40.0/3600)*pi/180);\nCD=AB_dash-AB_dash*ha/R;\nS=CD+CD**3/24.0/R**2;\n\n#result\nprint \"sea level length in m\",round(S,3)",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "sea level length in m 25108.53\n"
+      }
+     ],
+     "prompt_number": 2
+    },
+    {
+     "cell_type": "heading",
+     "level": 3,
+     "metadata": {},
+     "source": "Example 3.2,Page 50"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,tan,sqrt,sin,asin\nAB=31325.14\nR=6370.0e3;#radius of earth\nha=1582.15;\nh=2669.17\n\n#calculation\nAB_dash=AB-h**2/2/AB;\ntheta=2*asin(AB_dash/2/R);\nAB_dash=AB-(h*sin(theta/2)+h**2/AB/2)\nCD=AB_dash-AB_dash*ha/R;\nS=CD+CD**3/24.0/R**2;\n\n#result\nprint \"sea level length in m\",round(S,3)",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "sea level length in m 31197.163\n"
+      }
+     ],
+     "prompt_number": 9
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 3.3,Page 53"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,tan,sqrt,sin, acos\nAB=1525.456;\nBC=2176.945;\nCD=1697.435;\nAD=2401.435;\nAC=3073.845;\nBD=2483.115;\n\n#calculation\n#alpha=A and beta=B and those are angles\nA1=acos((CD**2+AC**2-AD**2)/(2*CD*AC));\nA1=A1*180/pi;\nA2=acos((AD**2+BD**2-AB**2)/(2*AD*BD));\nA2=A2*180/pi;\nA3=acos((AB**2+AC**2-BC**2)/(2*AB*AC));\nA3=A3*180/pi;\nA4=acos((BC**2+BD**2-CD**2)/(2*BC*BD));\nA4=A4*180/pi;\nB1=acos((CD**2+BD**2-BC**2)/(2*CD*BD));\nB1=B1*180/pi;\nB2=acos((AD**2+AC**2-CD**2)/(2*AD*AC));\nB2=B2*180/pi;\nB3=acos((AB**2+BD**2-AD**2)/(2*AB*BD));\nB3=B3*180/pi;\nB4=acos((AC**2+BC**2-AB**2)/(2*AC*BC));\nB4=B4*180/pi;\ne1=360-A1-A2-A3-A4-B1-B2-B3-B4;#error\ne2=A1+B1-A3-B3;#error\ne3=A2+B2-A4-B4;#error\n#angle update\nA1=A1+e1/8-e2/4;\nA3=A3+e1/8+e2/4;\nB1=B1+e1/8-e2/4;\nB3=B3+e1/8+e2/4;\nA2=A2+e1/8-e3/4;\nB2=B2+e1/8-e3/4;\nA4=A4+e1/8+e3/4;\nB4=B4+e1/8+e3/4;\n#updating sides\nAD=1525.456*sin(B3*pi/180)/sin(A2*pi/180);\nBD=1525.456*sin(A3*pi/180+B3*pi/180)/sin(A2*pi/180);\nAC=1525.456*sin(A4*pi/180+B3*pi/180)/sin(B4*pi/180);\nBC=1525.456*sin(A3*pi/180)/sin(B4*pi/180);\nCD=BC*sin(A4*pi/180)/sin(B1*pi/180)\n\n#result\n\nprint \"equation for B2 is wrong\"\nprint \"corrected length of AD in m \",round(AD,3)\nprint \"corrected length of AC in m \",round(AC,3)\nprint \"corrected length of BD in m \",round(BD,3)\nprint \"corrected length of BC in m \",round(BC,3)\nprint \"corrected length of CD in m \",round(CD,3)\n",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "27.5965629411\nequation for B2 is wrong\ncorrected length of AD in m  2401.251\ncorrected length of AC in m  3073.446\ncorrected length of BD in m  2413.581\ncorrected length of BC in m  2176.758\ncorrected length of CD in m  1697.416\n"
+      }
+     ],
+     "prompt_number": 25
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 3.4,Page 59"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,tan,sqrt,log,sin\n#angles found by cosine law\n#alpha=A and beta=B and those are angles\nA1=45.801596;\nA2=40.605250;\nA3=50.143258;\nA4=43.077646;\nB1=48.779868;\nB2=44.141587;\nB3=49.733152;\nB4=37.737035;\n\n#calculation\ne1=360-A1-A2-A3-A4-B1-B2-B3-B4;#error\n#angle update\nA1=A1+e1/8;\nA3=A3+e1/8;\nB1=B1+e1/8;\nB3=B3+e1/8;\nA2=A2+e1/8;\nB2=B2+e1/8;\nA4=A4+e1/8;\nB4=B4+e1/8;\nE2=log(sin(A1*pi/180),10)*log(sin(A2*pi/180),10)*log(sin(A3*pi/180),10)*log(sin(A4*pi/180),10)-log(sin(B1*pi/180),10)*log(sin(B2*pi/180),10)*log(sin(B3*pi/180),10)*log(sin(B4*pi/180),10);\nc3=E2/17.1;\nc4=E2/17.0;\nA1=A1-c3;\nB1=B1+c3;\n\n#result\nprint \"corrected angle A1 in degrees\",A1,\"corrected angle B1 in degrees\",B1",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "corrected angle A1 in degrees 45.7991704812 corrected angle B1 in degrees 48.7774455188\n"
+      }
+     ],
+     "prompt_number": 2
+    }
+   ],
+   "metadata": {}
+  }
+ ]
+}
\ No newline at end of file
diff --git a/Surveying_Volume_3/Chapter4.ipynb b/Surveying_Volume_3/Chapter4.ipynb
new file mode 100755
index 00000000..f2b5c7ec
--- /dev/null
+++ b/Surveying_Volume_3/Chapter4.ipynb
@@ -0,0 +1,970 @@
+{
+ "metadata": {
+  "name": "S3-C4"
+ },
+ "nbformat": 3,
+ "nbformat_minor": 0,
+ "worksheets": [
+  {
+   "cells": [
+    {
+     "cell_type": "heading",
+     "level": 1,
+     "metadata": {},
+     "source": "Principles of Field Astronomy"
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 4.1,Page 81"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    sd=round(sd,2)\n    return [d, m, sd]\ntheta=25+14.0/60;\nR=6370.0;\n\n#calculation\nAB=cos(theta*pi/180)*(16+10.0/60)\ndis=2*pi*R*AB/360.0;\n\n#result\nprint \"distance of AB in m \",round(dis,3)",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "distance of AB in m  1625.863\n"
+      }
+     ],
+     "prompt_number": 2
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 4.2,Page 81"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nimport numpy as np\nfrom scipy import linalg\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    sd=round(sd,2)\n    return [d, m, sd]\nLongA=52+24.0/60;\nLongB=55+30.0/60;\nlatA=18+10.0/60;\nlatB=15.0;\nR=6370.0;#radius of earth\n\n#calculation\nP=LongB-LongA;\nPA=90-latA;\nPB=90-latB;\nAB=acos(cos(PB*pi/180)*cos(PA*pi/180)+sin(PB*pi/180)*sin(PA*pi/180)*cos(P*pi/180));\ndis=AB*R;\n#solving for A\na = np.array([[0.5,0.5], [0.5,-0.5]])\nb = np.array([atan(cos((PB/2-PA/2)*pi/180)/tan(P*pi/180)/cos((PB/2+PA/2)*pi/180))*180/pi,atan(sin((PB/2-PA/2)*pi/180)/tan(P*pi/180)/sin((PB/2+PA/2)*pi/180))*180/pi])\nx = np.linalg.solve(a, b)\nA=x[0];\nA=deg_to_dms(A);\n\n#result\nprint \"distance of AB in km \",round(dis,2)\nprint \"direction of B to A in deg min sec\",A",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "distance of AB in km  482.72\ndirection of B to A in deg min sec [117, 8, 30.72]\n"
+      }
+     ],
+     "prompt_number": 2
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 4.3,Page 83"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    sd=round(sd,2)\n    return [d, m, sd]\nb=40.0;\np=6.0;\n\n#calculation\na=pi/2-asin(cos(b*pi/180)*cos(p*pi/180));\nBC=a*180/pi-b;\nBC=BC*1.853*60;\nB=asin(sin(b*pi/180)/sin(a))\nB=deg_to_dms(B*180/pi);\n\n#result\nprint \"distance BC in km\",round(BC,2)\nprint \"angle of B deg min sec\",B",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "distance BC in km 41.43\nangle of B deg min sec [82, 53, 56.83]\n"
+      }
+     ],
+     "prompt_number": 12
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 4.4,Page 105"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    sd=round(sd,2)\n    return [d, m, sd]\ncoal=90.0-28.0-24.0/60;#coaltitude\ncola=90.0-48.0-30.0/60;#colatitude\n\n\n#calculation\ndelta=pi/2-acos((cos(coal*pi/180)*cos(cola*pi/180)+sin(coal*pi/180)*sin(cola*pi/180)*cos(50*pi/180)));\nH=acos(cos(coal*pi/180)/(sin(cola*pi/180)*cos(delta))-tan(delta)/tan(cola*pi/180));\nH=deg_to_dms(H*180/pi);       \ndelta=deg_to_dms(delta*180/pi);  \n\n#result\nprint \"H in deg min sec\",H\nprint \"declination in deg mi sec\",delta",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "H in deg min sec [99, 7, 55.94]\ndelta in deg mi sec [46, 57, 38.26]\n"
+      }
+     ],
+     "prompt_number": 25
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 4.5,Page 107"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    sd=round(sd,2)\n    return [d, m, sd]\ndelta=22+45.0/60;\ntheta=55.0;\nH=45+15.0/60;\n\n#calculation\nalpha=asin((cos(H*pi/180)+tan(theta*pi/180)*tan(delta*pi/180))*cos(theta*pi/180)*cos(delta*pi/180));\nalpha=alpha*180/pi;\nA=acos(sin(delta*pi/180)/(cos(theta*pi/180)*cos(alpha*pi/180))-tan(alpha*pi/180)*tan(theta*pi/180));\nA=deg_to_dms(360-A*180/pi);\n\n#result\nprint \"azimuth in deg mi sec\",A",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "azimuth in deg mi sec [244, 40, 8.11]\n"
+      }
+     ],
+     "prompt_number": 17
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 4.6,Page 109"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    sd=round(sd,2)\n    return [d, m, sd]\ncoal=42.0;\ncode=100+40.0/60;#co-declination\n\n#calculation\nalpha=pi/2-acos((cos(coal*pi/180)*cos(code*pi/180)+sin(coal*pi/180)*sin(code*pi/180)*cos(35*pi/180)));\nA=acos((cos(code*pi/180)-cos(coal*pi/180)*cos(pi/2-alpha))/(sin(coal*pi/180)*sin(pi/2-alpha)));\nA=deg_to_dms(A*180/pi);\nalpha=deg_to_dms(alpha*180/pi);\n\n#result\nprint \"azimuth in deg min sec\",A\nprint \"alpha in deg min sec\",alpha",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "azimuth in deg mi sec [142, 1, 26.46]\nalpha in deg min sec [23, 38, 48.21]\n"
+      }
+     ],
+     "prompt_number": 33
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 4.7,Page 113"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    sd=round(sd,2)\n    return [d, m, sd]\ntheta=33+42.0/60+34.0/3600;\ndelta=81+55.0/60+14.0/3600;\n\n#calculation\nH1=acos(tan(theta*pi/180)/tan(delta*pi/180));\nH1=deg_to_dms(360-H1*180/pi);\nalpha=asin(sin(theta*pi/180)/sin(delta*pi/180));\nalpha=deg_to_dms(alpha*180/pi);\nA=asin(cos(delta*pi/180)/cos(theta*pi/180));\nA=deg_to_dms(A*180/pi);\n\n\n#result\nprint \"azimuth in deg min sec\",A\nprint \"alpha in deg min sec\",alpha\nprint \"hour angle in deg min sec\",H1",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "azimuth in deg min sec [9, 43, 37.11]\nalpha in deg min sec [34, 5, 36.7]\nhour angle in deg min sec [275, 26, 3.85]\n"
+      }
+     ],
+     "prompt_number": 41
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 4.8,Page 114"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    sd=round(sd,2)\n    return [d, m, sd]\nalpha=0.0;\ntheta=25+45.0/60;\n\n#calculation\ndelta=asin(sin(alpha)/sin(theta*pi/180));\n\n#result\nprint \"declination in degrees\",delta",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "declination in degrees 0.0\n"
+      }
+     ],
+     "prompt_number": 42
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 4.9,Page 116"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    sd=round(sd,2)\n    return [d, m, sd]\ncola=90.0-49.0;#colatitude\ncode=90.0+19.0;#codeclination\n\n#calculation\nA1=acos((cos(code*pi/180)-cos(cola*pi/180)*cos(pi/2))/sin(cola*pi/180)/sin(pi/2));\nA1=deg_to_dms(360-A1*180/pi);\nH=acos((0-cos(cola*pi/180)*cos(code*pi/180))/sin(cola*pi/180)*sin(code*pi/180));\nH=deg_to_dms(H*180/pi)\n\n#result\nprint \"azimuth in deg min sec\",A1\nprint \"hour angle in deg min sec\",H",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "azimuth in deg min sec [240, 14, 52.45]\nhour angle in deg min sec [69, 15, 38.0]\n"
+      }
+     ],
+     "prompt_number": 18
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 4.10,Page 120"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    sd=round(sd,2)\n    return [d, m, sd]\n#part1\ndelta=38+15.0/60;\ntheta=25+10.0/60;\n\n#calculation\nz=delta-theta;\nalpha=90-z;\nz=deg_to_dms(z);\nalpha=deg_to_dms(alpha);\n\n#result\nprint \"zenith distance in deg min sec\",z\nprint \"altitude in deg min sec\",alpha\n\n#part2\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    if sd==60:\n        m=m+1;\n        sd=0;\n       \n    sd=round(sd,2)\n    return [d, m, sd]\ndelta=22+40.0/60;\ntheta=25+10.0/60;\n\n#calculation\nz=-delta+theta;\nalpha=90-z;\nz=deg_to_dms(z);\nalpha=deg_to_dms(alpha);\n\n#result\nprint \"zenith distance in deg min sec\",z\nprint \"altitude in deg min sec\",alpha\n\n#part3\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md+1)\n    sd = (md - m) * 60\n    sd=round(sd,2)\n    return [d, m, sd]\ndelta=70+20.0/60;\ntheta=25+10.0/60;\n\n#calculation\nz=delta-theta;\nz=deg_to_dms(z);\n\n\n#result\nprint \"zenith distance in deg min sec\",z\n\n",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "zenith distance in deg min sec [13, 4, 60.0]\naltitude in deg min sec [76, 55, 0.0]\nzenith distance in deg min sec [2, 30, 0.0]\naltitude in deg min sec [87, 30, 0.0]\nzenith distance in deg min sec [45, 10, -0.0]\n"
+      }
+     ],
+     "prompt_number": 20
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 4.11,Page 122"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    if sd==60:\n        m=m+1;\n        sd=0;\n       \n    sd=round(sd,2)\n    return [d, m, sd]\ntheta=42+50.0/60;\ndelta=83+40.0/60;\n\n#calculation\nz=180-delta-theta;\nalpha=90-z;\nz=deg_to_dms(z);\nalpha=deg_to_dms(alpha);\n\n#result\nprint \"zenith distance in deg min sec\",z\nprint \"altitude in deg min sec\",alpha",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "zenith distance in deg min sec [53, 29, 60.0]\naltitude in deg min sec [36, 30, 0.0]\n"
+      }
+     ],
+     "prompt_number": 21
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 4.12,Page 133"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    if sd==60:\n        m=m+1;\n        sd=0;\n       \n    sd=round(sd,2)\n    return [d, m, sd]\n#part1\ndol=110-82-30.0/60; #differnce in longitude\nST=18+35.0/60+10.0/3600;#standard time\n\n#calculation\nLMT=ST+dol/15.0;\nLMT=deg_to_dms(LMT);\n\n#result\nprint \"LMT in hr min sec\",LMT\n\n#part2\ndol=82+30.0/60+30; #differnce in longitude\nST=18+35.0/60+10.0/3600;#standard time\n\n#calculation\nLMT=ST-dol/15.0;\nLMT=deg_to_dms(LMT);\n\n#result\nprint \"LMT in hr min sec\",LMT\n\n#part1\ndol=82+30.0/60-30; #differnce in longitude\nST=18+35.0/60+10.0/3600;#standard time\n\n#calculation\nLMT=ST-dol/15.0;\nLMT=deg_to_dms(LMT);\n\n#result\nprint \"LMT in hr min sec\",LMT",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "LMT in hr min sec [20, 25, 10.0]\nLMT in hr min sec [11, 5, 10.0]\nLMT in hr min sec [15, 5, 10.0]\n"
+      }
+     ],
+     "prompt_number": 66
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 4.13,Page 134"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    if sd==60:\n        m=m+1;\n        sd=0;\n       \n    sd=round(sd,2)\n    return [d, m, sd]\n#part1\nLMT=8+30.0/60+15.0/3600;\nLong=45+30.0/60;\n\n#calculation\nGMT=LMT+Long/15.0;\nGMT=deg_to_dms(GMT)\n\n#result\nprint \"GMT in hr min sec (AM)\",GMT\n\n\n#part2\nLMT=6+40.0/60+10.0/3600;\nLong=55+30.0/60;\n\n#calculation\nGMT=LMT-Long/15.0;\nGMT=deg_to_dms(GMT)\n\n#result\nprint \"GMT in hr min sec (PM)\",GMT",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "GMT in hr min sec (AM) [11, 32, 15.0]\nGMT in hr min sec (PM) [2, 58, 10.0]\n"
+      }
+     ],
+     "prompt_number": 71
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 4.14,Page 134"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    if sd==60:\n        m=m+1;\n        sd=0;\n       \n    sd=round(sd,2)\n    return [d, m, sd]\n#part1\nGMT=20+30.0/60+15.0/3600;\nLong=82+30.0/60;\n\n#calculation\nLMT=GMT+Long/15.0-24;\nLMT=deg_to_dms(LMT);\n\n#result\nprint \"LMT in hr min sec (next day)\",LMT\n\n#part1\nGMT=20+30.0/60+15.0/3600;\nLong=120.0;\n\n#calculation\nLMT=GMT-Long/15.0;\nLMT=deg_to_dms(LMT);\n\n#result\nprint \"LMT in hr min sec (same day)\",LMT",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "LMT in hr min sec (next day) [2, 0, 15.0]\nLMT in hr min sec (same day) [12, 30, 15.0]\n"
+      }
+     ],
+     "prompt_number": 74
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 4.15,Page 135"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    if sd==60:\n        m=m+1;\n        sd=0;\n       \n    sd=round(sd,2)\n    return [d, m, sd]\n#part1\nRA=6+15.0/60+20.0/3600;\nHA=8+10.0/60+30.0/3600;\n\n#calculation\nLST=RA+HA;\nLST=deg_to_dms(LST);\n\n#result\nprint \"LST in hr min sec\",LST\n\n#part2\nRA=8+40.0/60+15.0/3600;\nHA=3+50.0/60+20.0/3600;\n\n#calculation\nLST=RA-HA;\nLST=deg_to_dms(LST);\n\n#result\nprint \"LST in hr min sec\",LST\n",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "LST in hr min sec [14, 25, 50.0]\nLST in hr min sec [4, 49, 55.0]\n"
+      }
+     ],
+     "prompt_number": 76
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 4.16,Page 135"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    if sd==60:\n        m=m+1;\n        sd=0;\n       \n    sd=round(sd,2)\n    return [d, m, sd]\n#part1\nLHA=6+30.0/60+10.0/3600;\n\n#calculation\nLAT=LHA+12;\nLAT=deg_to_dms(LAT);\n\n#result\nprint \"LAT in hr min sec\",LAT;\n\n#part2\nLHA=18+40.0/60+20.0/3600;\n\n#calculation\nLAT=LHA+12-24;\nLAT=deg_to_dms(LAT);\n\n#result\nprint \"LAT in hr min sec\",LAT;",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "LAT in hr min sec [18, 30, 10.0]\nLAT in hr min sec [6, 40, 20.0]\n"
+      }
+     ],
+     "prompt_number": 78
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 4.17,Page 136"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    if sd==60:\n        m=m+1;\n        sd=0;\n       \n    sd=round(sd,2)\n    return [d, m, sd]\nLong=60.0;\nLHA=5+30.0/60+20.0/3600;\n\n#calculation\nGMT=LHA+12-Long/15.0;\nGMT=deg_to_dms(GMT);\n\n#result\nprint \"GMT in hr min sec\",GMT\n",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "GMT in hr min sec [13, 30, 20.0]\n"
+      }
+     ],
+     "prompt_number": 79
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 4.18,Page 138"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    if sd==60:\n        m=m+1;\n        sd=0;\n       \n    sd=round(sd,2)\n    return [d, m, sd]\n#parta\nGMT=0;\nET=10.0/60+1.8/3600;\n\n#calculaion\nGAT=GMT+ET;\nGAT=deg_to_dms(GAT);\n\n#result\nprint \"GAT in hr min sec\",GAT\n\n#partb\nGMT=0;\nET=-13.0/60-28.5/3600;\n\n#calculaion\nGAT=GMT+ET+24;\nGAT=deg_to_dms(GAT);\n\n#result\nprint \"GAT in hr min sec\",GAT",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "GAT in hr min sec [0, 10, 1.8]\nGAT in hr min sec [23, 46, 31.5]\n"
+      }
+     ],
+     "prompt_number": 81
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 4.19,Page 138"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    if sd==60:\n        m=m+1;\n        sd=0;\n       \n    sd=round(sd,2)\n    return [d, m, sd]\nET1=-3.0/60-51.4/3600; #ET at april 2\nET2=-3.0/60-33.5/3600; #ET at april 3\n\n#calculation\ndET=(ET2-ET1)*18.0/24; #change in ET\nET=ET1+dET;\nET=deg_to_dms(ET);\n\n#result\nprint \"ET (-ve) in hr min s\",ET",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "ET in hr min s [0, 3, 37.97]\n"
+      }
+     ],
+     "prompt_number": 83
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 4.20,Page 138"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    if sd==60:\n        m=m+1;\n        sd=0;\n       \n    sd=round(sd,2)\n    return [d, m, sd]\nLAT=15+12.0/60+40.0/3600;\nLong=20+3.0/60;\nGMN=5.0/60+10.65/3600;\n\n#calculation\nGAT=LAT+Long/15.0;\ne1=(GAT-12)*0.22/3600+GMN;\nLAT=GAT+e1-Long/15.0;\nLAT=deg_to_dms(LAT);\n\n#result\nprint \"LAT in hr min sec\",LAT\n",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "LAT in hr min sec [15, 17, 51.65]\n"
+      }
+     ],
+     "prompt_number": 84
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 4.21,Page 139"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    if sd==60:\n        m=m+1;\n        sd=0;\n       \n    sd=round(sd,2)\n    return [d, m, sd]\nLong=56+35.0/60;\nLMT=7+15.0/60+25.0/3600;\nGMN=3.0/60+54.0/3600;\n\n#calculation\nGMT=LMT-Long/15.0;\ne1=GMN+(12-GMN)*0.25/3600;\nLAT=GMT+Long/15.0+e1;\nLAT=deg_to_dms(LAT);\n\n#result\nprint \"LAT in hr min sec\",LAT\n",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "LAT in hr min sec [7, 19, 21.98]\n"
+      }
+     ],
+     "prompt_number": 86
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 4.22,Page 142"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    if sd==60:\n        m=m+1;\n        sd=0;\n       \n    sd=round(sd,2)\n    return [d, m, sd]\nST=7+15.0/60+30.0/3600;\n\n#calculation\ntr=9.8296/3600*ST;\nST=ST-tr;\nST=deg_to_dms(ST);\n\n#result\nprint \"solar mean time in hr min sec\",ST",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "solar mean time in hr min sec [7, 14, 18.65]\n"
+      }
+     ],
+     "prompt_number": 87
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 4.23,Page 142"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    if sd==60:\n        m=m+1;\n        sd=0;\n       \n    sd=round(sd,2)\n    return [d, m, sd]\nST=7+45.0/60+50.0/3600;\n\n#calculation\ntr=9.8565/3600*ST;\nST=ST+tr;\nST=deg_to_dms(ST);\n\n#result\nprint \"solar mean time in hr min sec\",ST",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "solar mean time in hr min sec [7, 47, 6.52]\n"
+      }
+     ],
+     "prompt_number": 90
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 4.24,Page 143"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#finding LST\n\n#initialisation of variable\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    if sd==60:\n        m=m+1;\n        sd=0;\n       \n    sd=round(sd,2)\n    return [d, m, sd]\nLong=140+35.0/60+20.0/3600;\nGST=13+15.0/60+30.0/3600;\n\n#calculation\nLST=GST+9.8565/3600*Long/15.0;\nLST=deg_to_dms(LST);\n\n#result\nprint \"LST in deg min sec\",LST\n\n#part2\nLong=160+45.0/60+30.0/3600;\nGST=13+15.0/60+30.0/3600;\n\n#calculation\nLST=GST-9.8565/3600*Long/15.0;\nLST=deg_to_dms(LST);\n\n#result\nprint \"LST in deg min sec\",LST",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "LST in deg min sec [13, 17, 2.38]\nLST in deg min sec [13, 13, 44.37]\n"
+      }
+     ],
+     "prompt_number": 93
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 4.25,Page 145"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    if sd==60:\n        m=m+1;\n        sd=0;\n       \n    sd=round(sd,2)\n    return [d, m, sd]\nLong=75.0;\nGST=15+55.0/60+13.0/3600;\nLMT=11.0;\n\n#calculation\nLST=GST+Long/15.0*9.8565/3600+LMT+9.8565/3600*LMT;\nLST=LST-24;\nLST=deg_to_dms(LST);\n\n#result\nprint \"LST of next day in deg min sec\",LST",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "LST of next day in deg min sec [2, 57, 50.7]\n"
+      }
+     ],
+     "prompt_number": 95
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 4.26,Page 145"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    if sd==60:\n        m=m+1;\n        sd=0;\n       \n    sd=round(sd,2)\n    return [d, m, sd]\nLong=75.0;\nGST=5+25.0/60+15.0/3600;\nLMT=5.0+40.0/60;\n\n#calculation\nLST=GST-Long/15.0*9.8565/3600+LMT+9.8565/3600*(LMT);\nLST=deg_to_dms(LST);\n\n#result\nprint \"LST of next day in deg min sec\",LST",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "LST of next day in deg min sec [11, 5, 21.57]\n"
+      }
+     ],
+     "prompt_number": 96
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 4.27,Page 146"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    if sd==60:\n        m=m+1;\n        sd=0;\n       \n    sd=round(sd,2)\n    return [d, m, sd]\nLong=75.0;\nGST=11+45.0/60+10.0/3600;\nLST=26+35.0/60+42.0/3600;\n\n#calculation\nLMM=GST+Long/15*9.8565/3600;\nLMT=LST-LMM-(LST-LMM)*9.8296/3600;\nLMT=deg_to_dms(LMT-12)\n\n#result\nprint \"LMT in hr min sec (PM)\",LMT \n\n",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "LMT in hr min sec (PM) [2, 47, 16.96]\n"
+      }
+     ],
+     "prompt_number": 97
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 4.28,Page 147"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    if sd==60:\n        m=m+1;\n        sd=0;\n       \n    sd=round(sd,2)\n    return [d, m, sd]\nLong=90.0;\nGST=9+15.0/60+14.0/3600;\nLST=31+35.0/60+12.0/3600;\n\n#calculation\nLMM=GST-Long/15*9.8565/3600;\nLMT=LST-LMM-(LST-LMM)*9.8296/3600;\nLMT=deg_to_dms(LMT-12)\n\n#result\nprint \"LMT in hr min sec (PM)\",LMT",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "LMT in hr min sec (PM) [10, 17, 17.46]\n"
+      }
+     ],
+     "prompt_number": 100
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 4.29,Page 149"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    if sd==60:\n        m=m+1;\n        sd=0;\n       \n    sd=round(sd,2)\n    return [d, m, sd]\nLong=150.0;\nGST=12+25.0/60+15.0/3600;\nLST=30+15.0/60+10.0/3600;\nLMN=18+15.0/60+10.0/3600;\n\n#calculation\nLMM=GST+Long/15*9.8565/3600;\nLMT=LMN-LMM-(LMN-LMM)*9.8296/3600;\nLMT=deg_to_dms(LMT)\n\n#result\nprint \"LMT in hr min sec (PM)\",LMT\n\n#part2\nLMM=GST+Long/15*9.8565/3600;\nLMT=LST-LMM-(LST-LMM)*9.8296/3600;\nLMT=deg_to_dms(LMT-12)\n\n#result\nprint \"LMT in hr min sec (AM)\",LMT",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "LMT in hr min sec (PM) [5, 47, 19.38]\nLMT in hr min sec (AM) [5, 45, 21.42]\n"
+      }
+     ],
+     "prompt_number": 102
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 4.30,Page 150 "
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    if sd==60:\n        m=m+1;\n        sd=0;\n       \n    sd=round(sd,2)\n    return [d, m, sd]\ntheta=35+15.0/60+20.0/3600;\ndelta=88+15.0/60+45.0/3600;\nRA=1+45.0/60+15.0/3600;\n\n#calculation\nH=acos(tan(theta*pi/180)/tan(delta*pi/180));\nH=H*180/pi/15;\nLST=RA+H;\nLST=deg_to_dms(LST);\n\n#result\nprint \"LST in hr min sec\",LST",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "LST in hr min sec [7, 40, 20.12]\n"
+      }
+     ],
+     "prompt_number": 103
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 4.31,Page 151"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    if sd==60:\n        m=m+1;\n        sd=0;\n       \n    sd=round(sd,2)\n    return [d, m, sd]\nRA=22+25.0/60+10.0/3600;\nST=14+45.0/60;#sidereal time\nLong=90.0;\nGMT=27+15.0/60;\nLMN=15+21.0/60+15.0/3600;\n\n#calculation\nMT=12+24-GMT+Long/15;#mean time interval\nacc=9.8565/3600*MT;\nHA=LMN-acc-MT;\nLST=HA+24-RA;\nLST=deg_to_dms(LST);\n\n#result\nprint \"LST in hr min sec\",LST\n",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "LST in hr min sec [2, 8, 39.62]\n"
+      }
+     ],
+     "prompt_number": 105
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 4.32,Page 152"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    if sd==60:\n        m=m+1;\n        sd=0;\n       \n    sd=round(sd,2)\n    return [d, m, sd]\nLong=60;\nGMT=11+15.0/60+20.0/3600;\n\n#calculation\nLMT=GMT-Long/15*9.8296/3600;\nLMT=deg_to_dms(LMT);\n\n#result\nprint \"LMT in hr min sec \",LMT\n\n#part2\nLong=45;\nGMT=11+15.0/60+20.0/3600;\n\n#calculation\nLMT=GMT+Long/15*9.8296/3600;\nLMT=deg_to_dms(LMT);\n\n#result\nprint \"LMT in hr min sec \",LMT\n",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "LMT in hr min sec  [11, 14, 40.68]\nLMT in hr min sec  [11, 15, 49.49]\n"
+      }
+     ],
+     "prompt_number": 107
+    },
+    {
+     "cell_type": "heading",
+     "level": 3,
+     "metadata": {},
+     "source": "Example 4.33,Page 153"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#finding LMT\n\n#initialisation of variable\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    if sd==60:\n        m=m+1;\n        sd=0;\n       \n    sd=round(sd,2)\n    return [d, m, sd]\nLong=75;\nGMT=6+18.0/60+20.0/3600;\nLST=10+25.0/60+15.0/3600;\n\n#calculation\nLMT=GMT+Long/15*9.8296/3600;\nLST=LST-9.8296/3600*LST;\nLMT=LMT+LST;\nLMT=deg_to_dms(LMT);\n\n#result\nprint \"LMT in hr min sec \",LMT",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "LMT in hr min sec  [16, 42, 41.72]\n"
+      }
+     ],
+     "prompt_number": 111
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 4.34,Page 154"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    if sd==60:\n        m=m+1;\n        sd=0;\n       \n    sd=round(sd,2)\n    return [d, m, sd]\nGST=7+35.0/60+40.0/3600;\n\n#calculation\nGMT=24-GST-(24-GST)*9.8296/3600;\nGMT=deg_to_dms(GMT);\n\n#result\nprint \"GMT in hr min sec\",GMT",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "GMT in hr min sec [16, 21, 38.74]\n"
+      }
+     ],
+     "prompt_number": 112
+    },
+    {
+     "cell_type": "heading",
+     "level": 3,
+     "metadata": {},
+     "source": "Example 4.34,Page 154"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#finding LMT\n\n#initialisation of variable\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    if sd==60:\n        m=m+1;\n        sd=0;\n       \n    sd=round(sd,2)\n    return [d, m, sd]\nLong=120.0;\nGMT=12+3.0/60+24.6/3600;\n\n#calculation\nLMT=GMT-17.8/24*Long/15.0/3600;\nLMT=deg_to_dms(LMT);\n\n#result\nprint \"LMT of LAN in hr min sec\",LMT\n\n#part2\nLong=45;\nGMT=12+3.0/60+24.6/3600;\n\n#calculation\nLMT=GMT+17.8/24*Long/15.0/3600;\nLMT=deg_to_dms(LMT);\n\n#result\nprint \"LMT of LAN in hr min sec\",LMT",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "LMT of LAN in hr min sec [12, 3, 18.67]\nLMT of LAN in hr min sec [12, 3, 26.83]\n"
+      }
+     ],
+     "prompt_number": 114
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 4.35,Page 156"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    if sd==60:\n        m=m+1;\n        sd=0;\n       \n    sd=round(sd,2)\n    return [d, m, sd]\n#one of the 2 solution\nf0=5+1.9/60;\nn=0.25;\ndel0=0;\ndel1=-0.1;\nd2=23.0;#del1/2\n\n#calculation\nfn=f0+n*d2/60+n*(n-1)/2*(del1+del0)/60;\nfn=deg_to_dms(fn)\n\n#result\nprint \"sun declination in deg min sec\",fn",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "sun declination in deg min sec [5, 7, 39.56]\n"
+      }
+     ],
+     "prompt_number": 117
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 4.36,Page 157"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    if sd==60:\n        m=m+1;\n        sd=0;\n       \n    sd=round(sd,2)\n    return [d, m, sd]\nalt=23+40.0/60;\nazi=145.0;\nlat=50.0;\n\n#calculation\ndelta=pi/2-acos(cos(pi/2-lat*pi/180)*cos(pi/2-alt*pi/180)+sin(pi/2-lat*pi/180)*sin(pi/2-alt*pi/180)*cos(azi*pi/180));\nH=acos((cos(pi/2-alt*pi/180)-cos(pi/2-lat*pi/180)*cos(pi/2-delta))/sin(pi/2-lat*pi/180)*sin(pi/2-delta))\nH=deg_to_dms(360-H*180/pi);\ndelta=deg_to_dms(delta*180/pi);\n\n#result\nprint \"there is a calculation mistake in calculating H in the book\"\nprint \"declination in deg min sec\",delta\nprint \"hour angle in deg min sec\",H",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "declination in deg min sec [-10, 3, 51.85]\nhour angle in deg min sec [325, 4, 44.11]\n"
+      }
+     ],
+     "prompt_number": 1
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 4.37,Page 158"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    if sd==60:\n        m=m+1;\n        sd=0;\n       \n    sd=round(sd,2)\n    return [d, m, sd]\nalt=25+30.0/60;\nazi=45.0;\nlat=42.0;\n\n#calculation\ndelta=pi/2-acos(cos(pi/2-lat*pi/180)*cos(pi/2-alt*pi/180)+sin(pi/2-lat*pi/180)*sin(pi/2-alt*pi/180)*cos(azi*pi/180));\nH=acos((cos(pi/2-alt*pi/180)-cos(pi/2-lat*pi/180)*cos(pi/2-delta))/sin(pi/2-lat*pi/180)*sin(pi/2-delta))\nH=deg_to_dms(H*180/pi);\ndelta=deg_to_dms(delta*180/pi);\n\n#result\nprint \"declination in deg min sec\",delta\nprint \"hour angle in deg min sec\",H",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "declination in deg min sec [49, 40, 22.06]\nhour angle in deg min sec [93, 58, 30.79]\n"
+      }
+     ],
+     "prompt_number": 122
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 4.38,Page 158"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#finding hour angle,azimuth\n\n#initialisation of variable\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    if sd==60:\n        m=m+1;\n        sd=0;\n       \n    sd=round(sd,2)\n    return [d, m, sd]\ndelta=21.0*pi/180+25.0/60*pi/180;\nlat=25+40.0/60;\n\n#calculation\nH=acos((0-cos(pi/2-lat*pi/180)*cos(pi/2-delta))/sin(pi/2-lat*pi/180)*sin(pi/2-delta));\nA=acos(cos(pi/2-delta)/sin(pi/2-lat*pi/180));\nH=deg_to_dms(360-H*180/pi);\nA=deg_to_dms(A*180/pi);\n\n#result\nprint \"hour angle in deg min sec\",H\nprint \"azimuth in deg min sec\",A",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "hour angle in deg min sec [260, 35, 53.78]\nazimuth in deg min sec [66, 6, 4.59]\n"
+      }
+     ],
+     "prompt_number": 130
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 4.39,Page 161"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#finding latitude\n\n#initialisation of variable\nimport numpy as np\nfrom scipy import linalg\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    if sd==60:\n        m=m+1;\n        sd=0;\n       \n    sd=round(sd,2)\n    return [d, m, sd]\n#calculation\nA=np.array([[1,1],[1,-1]]);\nb=np.array([[90],[0]]);\nx=np.linalg.solve(A,b);\n\n#result\nprint \"latitude in degrees\",x[0]",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "latitude in degrees [ 45.]"
+      },
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "\n"
+      }
+     ],
+     "prompt_number": 131
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 4.40,Page 161"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#finding altitude\n\n#initialisation of variable\nimport numpy as np\nfrom scipy import linalg\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    if sd==60:\n        m=m+1;\n        sd=0;\n       \n    sd=round(sd,2)\n    return [d, m, sd]\ntheta=53+20.0/60;\ndelta=53+20.0/60;\n\n#calculation\nalpha=theta+delta-90;\nalpha=deg_to_dms(alpha);\n\n#result\nprint \"altitude in deg min sec\",alpha",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "altitude in deg min sec [16, 40, 0.0]\n"
+      }
+     ],
+     "prompt_number": 132
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 4.41,Page 162"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#finding GAT\n\n#initialisation of variable\nimport numpy as np\nfrom scipy import linalg\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    if sd==60:\n        m=m+1;\n        sd=0;\n       \n    sd=round(sd,2)\n    return [d, m, sd]\nGMT=18+30.0/60;\nET=1.0/60+25.4/3600-0.67*6.5/3600;\n\n#calculation\nGAT=GMT+ET;\nGAT=deg_to_dms(GAT)\n\n#result\nprint \"GAT in hr min sec\",GAT",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "GAT in hr min sec [18, 31, 21.05]\n"
+      }
+     ],
+     "prompt_number": 133
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 4.42,Page 163"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#finding LMT\n\n#initialisation of variable\nimport numpy as np\nfrom scipy import linalg\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    if sd==60:\n        m=m+1;\n        sd=0;\n       \n    sd=round(sd,2)\n    return [d, m, sd]\nLong=30.0;\nGAT=13+15.0/60+10.0/3600;\nET=6.0/60+15.35/3600+0.3/3600*1.25278;\n\n#calculation\nLMT=GAT+ET-Long/15.0;\nLMT=deg_to_dms(LMT);\n\n#result\nprint \"LMT in hr min sec\",LMT",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "LMT in hr min sec [11, 21, 25.73]\n"
+      }
+     ],
+     "prompt_number": 134
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 4.43,Page 163"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#finding LHA\n\n#initialisation of variable\nimport numpy as np\nfrom scipy import linalg\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    if sd==60:\n        m=m+1;\n        sd=0;\n       \n    sd=round(sd,2)\n    return [d, m, sd]\nLong=45.0;\nE=11+55.0/60+5.0/3600-1.5/6*17.0/3/3600;\n\n#calculation\nGMT=14+40.0/60+Long/15.0;\nGHA=GMT+E;\nLHA=GHA-24-Long/15;\nLHA=deg_to_dms(LHA);\n\n#result\nprint \"LHA of the sun in hr min sec\",LHA\n",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "LHA of the sun in hr min sec [2, 35, 3.58]\n"
+      }
+     ],
+     "prompt_number": 135
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 4.44,Page 164"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#finding GMT\n\n#initialisation of variable\nimport numpy as np\nfrom scipy import linalg\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    if sd==60:\n        m=m+1;\n        sd=0;\n       \n    sd=round(sd,2)\n    return [d, m, sd]\nE=11+55.0/60+24.0/3600+0.5/3600*(2+40.0/60+21.2/3600);\nGHA=8+35.0/60+45.2/3600;\n\n#calculation\nGMT=GHA+24-E;\nGMT=deg_to_dms(GMT);\n\n#result\nprint \"GMT in hr min sec\",GMT",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "GMT in hr min sec [20, 40, 19.86]\n"
+      }
+     ],
+     "prompt_number": 136
+    }
+   ],
+   "metadata": {}
+  }
+ ]
+}
\ No newline at end of file
diff --git a/Surveying_Volume_3/Chapter5.ipynb b/Surveying_Volume_3/Chapter5.ipynb
new file mode 100755
index 00000000..4d4ee9e6
--- /dev/null
+++ b/Surveying_Volume_3/Chapter5.ipynb
@@ -0,0 +1,398 @@
+{
+ "metadata": {
+  "name": "S3-C5"
+ },
+ "nbformat": 3,
+ "nbformat_minor": 0,
+ "worksheets": [
+  {
+   "cells": [
+    {
+     "cell_type": "heading",
+     "level": 1,
+     "metadata": {},
+     "source": "Uses Of Field Astronomy in surveying"
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 5.1,Page 174"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    sd=round(sd,2)\n    return [d, m, sd]\n#printing result in degree minute and seconds respectively\nl1=11.5;\nl2=13.5;\nr1=8.5;\nr2=6.5;\nalpha=3+15.0/60+28.0/3600;\nOB=121+45.0/60+18.0/3600;\nOA=43+25.0/60+20.51/3600;\n\n#calculation\ngamma=(l1+l2)/4-(r1+r2)/4;\ne=gamma*tan(alpha*pi/180)/3600; #correction\nCH=OB-OA-e;\nCH=deg_to_dms(CH);\n\n#result\nprint \"corrected horizontal angle in deg,min,sec respectively\",CH",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "corrected horizontal angle in deg,min,sec respectively [78, 19, 57.35]\n"
+      }
+     ],
+     "prompt_number": 1
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 5.2,Page 184"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    sd=round(sd,2)\n    return [d, m, sd]\nalpha=30+32.0/60+18.0/3600;#latitude\nd=16.0/60+2.85/3600; #diameter of sun\n\n#calculation\nC1=-58.0/3600/tan(alpha*pi/180); \nC2=8.8/3600*cos(alpha*pi/180);   \nC3=d;      \nCL=alpha+C1+C2+C3;\nCL=deg_to_dms(CL);\n\n#result\nprint \"corrected latutude in deg,min,sec respectively\",CL",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "corrected latutude in deg,min,sec respectively [30, 46, 50.12]\n"
+      }
+     ],
+     "prompt_number": 1
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 5.3,Page 184"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    sd=round(sd,2)\n    return [d, m, sd]\nalpha=40+52.0/60+10.0/3600;#latitude\n\n#calculation\nC1=-58.0/3600/tan(alpha*pi/180);\nCL=alpha+C1;\nCL=deg_to_dms(CL);\n\n#result\nprint \"corrected latutude in deg,min,sec respectively\",CL",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "corrected latutude in deg,min,sec respectively [40, 51, 2.97]\n"
+      }
+     ],
+     "prompt_number": 2
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 5.4,Page 197"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    sd=round(sd,2)\n    return [d, m, sd]\nLMT=21+23.0/60+05.0/3600; #local chronometer time\nLong=65.0+19.0/60; #longitude\nGST=13+15.0/60+20.0/3600;\nRA=9+32.0/60+15.0/3600;\nLong2=82.0+30.0/60; #longitude of India\n\n#calculation\ne1=Long/15*9.8565/3600;  #error\nSIT=RA+24-GST+e1; #sidereal time interval after LMM\ne2=SIT*9.8296/3600; #error\nMI=SIT-e2; #mean interval after LMM\nLMT=LMT-(Long2-Long)/15.0;\nCE=MI-LMT;\nCE=deg_to_dms(CE);\n\n#result\nprint \"chronometer error in hours,min,sec respectively\",CE",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "chronometer error in hours,min,sec respectively [0, 0, 2.56]\n"
+      }
+     ],
+     "prompt_number": 3
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 5.5,Page 198"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    sd=round(sd,2)\n    return [d, m, sd]\nMST=12+32.0/60+15.0/3600; #mean sidereal time\nRA=15+45.0/60+10.0/3600;\ntheta=55+14.0/60+20.0/3600;#latitude\ndelta=15+24.0/60+30.0/3600;#declination\nalpha=35+44.0/60+10.0/3600;#zenith deistance\n\n#calculation\nc=90-theta;\np=90-delta;\nz=90-alpha;\nH=acos(cos(z*pi/180)/sin(c*pi/180)/sin(p*pi/180)-1/(tan(p*pi/180)*tan(c*pi/180)))\nH=H/15*180/pi;\nLST=RA-H;\nCE=MST-LST;\nCE=deg_to_dms(CE);\n\n#result\nprint \"chronometer error in hours,min,sec respectively\",CE",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "chronometer error in hours,min,sec respectively [0, 0, 12.94]\n"
+      }
+     ],
+     "prompt_number": 1
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 5.6,Page 199"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    sd=round(sd,2)\n    return [d, m, sd]\nLMTe=6+34.0/60+18.0/3600;#  LMT east\nLMTw=8+58.0/60+2.0/3600; # LMT west\nRA=16+11.0/60+25.0/3600;\nLong=125+33.0/60;\nGST=8+25.0/60+14.0/3600;\n\n#calculation\ne1=Long/15*9.8565/3600; #error\nSIT=RA-GST+e1; #sidereal time interval after LMM\ne2=SIT*9.8296/3600;\nMI=SIT-e2; #mean time interval after LMM\nLMTav=(LMTe+LMTw)/2; #mean LMT\nCE=LMTav-MI;\nCE=deg_to_dms(CE);\n\n#result\nprint \"chronometer error in slower side in hours,min,sec respectively\",CE",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "chronometer error in slower side in hours,min,sec respectively [0, 0, 6.9]\n"
+      }
+     ],
+     "prompt_number": 4
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 5.7,Page 204"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    sd=round(sd,2)\n    return [d, m, sd]\nLMM=15+9.0/60+5.21/3600;# mean LMT\nGMT=10+9.0/60+3.76/3600;\nLong=75.0;#longitude\nalpha=42+30.0/60+42.0/3600;\ntheta=34+48.0/60+12.0/3600;\ndelta=15+36.0/60+48.0/3600;\n\n#calculation\nH=acos(sin(alpha*pi/180)/cos(theta*pi/180)/cos(delta*pi/180)-(tan(delta*pi/180)*tan(theta*pi/180)))\nH=H/15*180/pi;\nGAT=12+H-Long/15;\nLMT=GAT+Long/15-5.0/60-40.0/3600;\nCE=LMM-LMT;\nCE=deg_to_dms(CE);\n\n#result\nprint \"chronometer error in slower side in hours,min,sec respectively\",CE",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "[0, 0, 1.45] chronometer error in slower side in hours,min,sec respectively\n"
+      }
+     ],
+     "prompt_number": 23
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 5.8,Page 219"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    sd=round(sd,2)\n    return [d, m, sd]\nd=5+1.0/60+50.0/3600;\ndel1=75+14.0/60+20.0/3600;\ndel2=70+12.0/60+30.0/3600;\n\n#calculation\nk=cos(del1*pi/180)/cos(del2*pi/180);\nA2=pi/2-atan((cos(d*pi/180)-k)/sin(d*pi/180));\nA2=A2*180/pi;\nA2=120+15.0/60+10.0/3600-A2;\nCR=360-A2;\nA2=deg_to_dms(A2);\nCR=deg_to_dms(CR);\n\n#result\nprint \"azimuth of angle R in degree,minites,seconds respectively\",A2\nprint \"true bearing of CR in degree,minites,seconds respectively\",CR",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "azimuth of angle R in degree,minites,seconds respectively [100, 27, 40.0]\ntrue bearing of CR in degree,minites,seconds respectively [259, 32, 20.0]\n"
+      }
+     ],
+     "prompt_number": 5
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 5.9,Page 223"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    sd=round(sd,2)\n    return [d, m, sd]\na=26.0/60+51.0/3600;\np=56.0/60+5.1/3600;#polar distance\n\n#calculation\nH=acos(a/p);\nA=p*sin(H)/cos(30.75694*pi/180);\nCR=25+35.0/60+40.0/3600-A;\nCR=deg_to_dms(CR);\n\n#result\nprint \"azimuth of angle CR in degree,minites,seconds respectively\",CR",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "azimuth of angle CR in degree,minites,seconds respectively [24, 38, 22.01]\n"
+      }
+     ],
+     "prompt_number": 6
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 5.10,Page 227 "
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    sd=round(sd,2)\n    return [d, m, sd]\nLong=75.0;#longitude\nGST=11+40.0/60+32.4/3600;\nRA=12+25.0/60+18.35/3600;\nGMT=15+45.0/60+25.3/3600;\ndelta=22+6.0/60+32.5/3600;\n\n#calculation\ne1=Long/15*9.8565/3600;\nLSTofLMM=GST-e1;\nLMT=GMT+Long/15;\nSIT=LMT+LMT*9.8565/3600;#sidereal time interval\nLHA=SIT+LSTofLMM;\nH=RA+24-LHA;\nH=H*15;\nB=atan(tan(delta*pi/180)*tan(H*pi/180));\nB=B*180/pi;\nA=atan(tan(H*pi/180)*cos(B*pi/180)/sin((B-32-15.0/60)*pi/180))\nA=A*180/pi;\nTB=360+A-135-15.0/60-20.0/3600;\nTB=deg_to_dms(TB);\n\n#result\nprint \"true bearing TB in degree,minites,seconds respectively\",TB\nprint \"there is slight difference in the answers due to rounding off error in the book\"",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "true bearing TB in degree,minites,seconds respectively [313, 17, 36.07]\nthere is slight difference in the answers due to rounding off error in the book\n"
+      }
+     ],
+     "prompt_number": 1
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 5.11,Page 237"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    sd=round(sd,2)\n    return [d, m, sd]\nz=51+47.0/60+18.0/3600;#zenith distance\np=88+57.0/60+57.0/3600;#polar distance\nc=61+27.0/60+55.0/3600;#co-latitude\n\n#calculation\ns=(z+p+c)/2;\nA=2*atan(sqrt(sin((s-z)*pi/180)/sin(s*pi/180)*sin((s-c)*pi/180)/sin((s-p)*pi/180)));\nA=A*180/pi;\nTB=360-A-165-18.0/60-20.0/3600;\nTB=deg_to_dms(TB);\n\n#result\nprint \"true bearing TB in degree,minites,seconds respectively\",TB",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "true bearing TB in degree,minites,seconds respectively [80, 59, 47.52]\n"
+      }
+     ],
+     "prompt_number": 8
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 5.12,Page 241"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#finding latitude\n\n#initialisation of variable\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    sd=round(sd,2)\n    return [d, m, sd]\nz2=90-40-13.0/60-15.0/3600;\ndel2=12+15.0/60+30.0/3600;#declination of star\n\n#calculation\ntheta=z2+del2;\ntheta=deg_to_dms(theta);\n\n#result\nprint \"altitude in degree,minites,seconds respectively\",theta",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "altitude in degree,minites,seconds respectively [62, 2, 15.0]\n"
+      }
+     ],
+     "prompt_number": 9
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 5.13,Page 244"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    sd=round(sd,2)\n    return [d, m, sd]\nalpha1=30+45.0/60+25.0/3600;\nalpha2=40+48.0/60+30.0/3600;\n\n#calculation\ne1=-58/3600/tan(alpha1*pi/180); #error 1\ne2=-58/3600/tan(alpha2*pi/180); #error 2\ntheta=(alpha1+alpha2+e1+e2)/2;\ntheta=deg_to_dms(theta)\n\n#result\nprint \"latitude in degree,minites,seconds respectively\",theta",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "latitude in degree,minites,seconds respectively [34, 21, 48.1]\n"
+      }
+     ],
+     "prompt_number": 10
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 5.14,Page 258"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    sd=round(sd,2)\n    return [d, m, sd]\nZP=37+29.0/60+40.0/3600;#colatitde\nZM=56+24.0/60+50.0/3600;#coaltitude\nPM=67+54.0/60+24.0/3600;#codeclination\n\n#calculation\nA1=acos((cos(PM*pi/180)-cos(ZP*pi/180)*cos(ZM*pi/180))/(sin(ZP*pi/180)*sin(ZM*pi/180)));\nA1=A1*180/pi;\nA=360-A1;\nA=deg_to_dms(A);\n\n#result\nprint \"azimuth of sun in degree,minites,seconds respectively\",A",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "azimuth of sun in degree,minites,seconds respectively [262, 53, 12.16]\n"
+      }
+     ],
+     "prompt_number": 11
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 5.15,Page 259"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    sd=round(sd,2)\n    return [d, m, sd]\ntheta=54+30.0/60;#latitude\ndelta=62+12.0/60+21.0/3600;#declination\n\n#calculation\nalpha=asin(sin(theta*pi/180)/sin(delta*pi/180));\nA1=acos(tan(theta*pi/180)/tan(alpha));\nA1=A1*180/pi;\nTB=360-A1-65-18.0/60-42.0/3600;\nTB=deg_to_dms(TB);\nalpha=deg_to_dms(alpha*180/pi);\nH=atan(tan(theta*pi/180)/tan(delta*pi/180));\nH=deg_to_dms(H*180/pi);\n\n#result\nprint \"true bearing in degree,minites,seconds respectively\",TB\nprint \"altitude in degree,minites,seconds respectively\",alpha\nprint \"hour angle in degree,minites,seconds respectively\",H",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "true bearing in degree,minites,seconds respectively [241, 16, 19.55]\naltitude in degree,minites,seconds respectively [66, 58, 7.13]\nhour angle in degree,minites,seconds respectively [36, 27, 49.32]\n"
+      }
+     ],
+     "prompt_number": 12
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 5.16,Page 261"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    sd=round(sd,2)\n    return [d, m, sd]\nalpha=44+12.0/60+30.0/3600;\nd=15.0/60+45.86/3600;#diameter correction\nLong=7+20.0/60+15.0/3600;#longitude\n\n#calculation\nalpha=alpha+d-58/3600/tan(alpha)+8.8/3600*cos(alpha);\nGAT=Long/15;\ne2=6.82/3600*GAT;\ndelta=22+18.0/60+12.8/3600+e2;\ntheta=delta+90-alpha;\ntheta=deg_to_dms(theta);\n\n#result\nprint \"altitude in degree,minites,seconds respectively\",theta",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "[67, 49, 51.7] altitude in degree,minites,seconds respectively\n"
+      }
+     ],
+     "prompt_number": 47
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 5.17,Page 262"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    sd=round(sd,2)\n    return [d, m, sd]\nGMT=16+22.0/60+55.0/3600;\nET=3.0/60+43.0/3600;\nc=90-42-20.0/60;\np=90-18-45.0/60-50.0/60;\nz=90-43-38.0/60;\n\n#calculation\nH=acos(cos(z*pi/180)/sin(c*pi/180)/sin(p*pi/180)-1/tan(c*pi/180)*1/tan(p*pi/180));\nH=H*180/pi;\nLAT=12-H/15;\nLMT=LAT-ET;\nLong=GMT-LMT;\nLong=Long*15;\nLong=deg_to_dms(Long);\n\n#result\nprint \"Longitude in degree,minites,seconds respectively\",Long",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "Longitude in degree,minites,seconds respectively [114, 50, 53.21]\n"
+      }
+     ],
+     "prompt_number": 4
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 5.18,Page 263"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,tan,sqrt,sin,cos,acos,atan,asin\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    sd=round(sd,2)\n    return [d, m, sd]\nalpha=21+35.0/60+30.0/3600;#mean observed altitude\nC=(4.5+5.5-3.5-2.5)/4*15.0/3600;\nc=44+30.0/60;#colatitude\nz=68+26.0/60+34.0/3600;#coaltitude\np=94+4.0/60+15.0/3600;#codeclination\ns=(c+p+z)/2;\n\n#calculation\ncr=-58/3600/tan(alpha);#correction refraction\ncp=8.8/3600*cos(alpha);#correction parallax\nalpha=alpha+C+cr+cp;  #corrected altitude\nA=2*atan(sqrt(sin((s-z)*pi/180)/sin(s*pi/180)*sin((s-c)*pi/180)/sin((s-p)*pi/180)));\nA=A*180/pi;\nMh=(121+45.0/60+20.0/3600+122+47.0/60)/2;#mean horizontal angle\nAZ=360-Mh-A;\nAZ=deg_to_dms(AZ);\n\n#result\nprint \"Azimuth from north(clockwise) in degree,minites,seconds respectively\",AZ",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "[117, 0, 19.45] Azimuth from north(clockwise) in degree,minites,seconds respectively\n"
+      }
+     ],
+     "prompt_number": 55
+    }
+   ],
+   "metadata": {}
+  }
+ ]
+}
\ No newline at end of file
diff --git a/Surveying_Volume_3/Chapter6.ipynb b/Surveying_Volume_3/Chapter6.ipynb
new file mode 100755
index 00000000..3fb19c9c
--- /dev/null
+++ b/Surveying_Volume_3/Chapter6.ipynb
@@ -0,0 +1,629 @@
+{
+ "metadata": {
+  "name": "S3-C6"
+ },
+ "nbformat": 3,
+ "nbformat_minor": 0,
+ "worksheets": [
+  {
+   "cells": [
+    {
+     "cell_type": "heading",
+     "level": 1,
+     "metadata": {},
+     "source": "Photogrammetry"
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 6.1,Page 281"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,sqrt,acos,asin,atan,cos,sin,tan\nDa=184.32;\nDb=95.84;\nAx=-115.0\nBy=-115.0;\n\n#calculation\nphi=atan(Ax/By);\nAB=sqrt(Ax**2+By**2);\ntheta=acos((Da**2+AB**2-Db**2)/2/Da/AB);\nalpha=phi-theta;\nxc=Da*cos(alpha)-115.0;\nyc=-Da*sin(alpha);\n\n#result\nprint \"the coordiantes in mm x is\",round(xc),\"y is\",round(yc,2)",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "the coordiantes in mm x is 64.0 y is -43.72\n"
+      }
+     ],
+     "prompt_number": 1
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 6.2,Page 290"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,sqrt,acos,asin,atan,cos,sin,tan\nf=0.152;\nH=1800;#elevation of topmost point\nh=300;#elevation of ground\n\n#calculation\nS=f/(H-h);\n\n#result\nprint  \"scale of photograph in 1 in\",round(1/S)",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "scale of photograph in 1 in 9868.0\n"
+      }
+     ],
+     "prompt_number": 8
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 6.3,Page 290"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,sqrt,acos,asin,atan,cos,sin,tan\nf=0.150 #focal length\nh1=1500.0;#elevation A\nh2=1200.0;#elevation B\nh3=1000.0;#elevation C\nH=3000.0;#height\n\n#calculation\nhav=1.0/3*(h1+h2+h3);\nS1=f/(H-h1);\nS2=f/(H-h2);\nS3=f/(H-h3);\nSav=f/(H-hav);\n\n#result\nprint  \"scale of point 1 in 1 in\",round(1/S1);\nprint  \"scale of point 2 in 1 in\",round(1/S2);\nprint  \"scale of point 3 in 1 in\",round(1/S3);\nprint  \"average scale  in 1 in\",round(1/Sav);",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "scale of point 1 in 1 in 10000.0\nscale of point 2 in 1 in 12000.0\nscale of point 3 in 1 in 13333.0\naverage scale  in 1 in 11778.0\n"
+      }
+     ],
+     "prompt_number": 13
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 6.4,Page 292"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,sqrt,acos,asin,atan,cos,sin,tan\nab=188.0;\nAB=120;\nSm=1.0/20000;\n\n#calculation\nS=ab/AB*Sm;\n\n#result\nprint  \"scale of photograph in 1 in\",round(1/S)",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "scale of photograph in 1 in 12766.0\n"
+      }
+     ],
+     "prompt_number": 15
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 6.5,Page 295"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,sqrt,acos,asin,atan,cos,sin,tan\nxa=45.35;\nxb=-40.16;\nf=152.4;#focal length\nH=1500.0;#actual height\nha=200.0;#height A\nhb=150.0;#height B\nya=38.41;\nyb=-45.65;\n\n#calculation\nXa=xa*(H-ha)/f;\nYa=ya*(H-hb)/f;\nXb=xb*(H-ha)/f;\nYb=yb*(H-hb)/f;\nAB=sqrt((Xb-Xa)**2+(Yb-Ya)**2);\n\n#result\nprint \"distance of AB in m\",round(AB,3)",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "distance of AB in m 1042.361\n"
+      }
+     ],
+     "prompt_number": 1
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 6.6,Page298"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,sqrt,acos,asin,atan,cos,sin,tan\nd=62.4;#displacement\nH=250.0;#height of datum\nr=115.4;#image distance\n\n#calculation\nh=H*d/r;\n\n#result\nprint \"height of chimney in m\",round(h,3)",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "height of chimney in m 135.182\n"
+      }
+     ],
+     "prompt_number": 2
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 6.7,Page 299"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,sqrt,acos,asin,atan,cos,sin,tan\nra=88.25;#image distance of A\nrb=81.23;#image distance of B\nrc=68.14;#image distance of C\nH=2000.0;\nha=255;\nhb=200;\nhc=145;\nf=0.1524;\n\n#calculation\naa=ra*ha/H;\nbb=rb*hb/H;\ncc=rc*hc/H;\nS=f/H;\n\n#result\nprint \"relief distance of A in mm\",round(aa,2)\nprint \"relief distance of B in mm\",round(bb,2)\nprint \"relief distance of C in mm\",round(cc,2)\nprint  \"scale of photograph in 1 in\",round(1/S)",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "relief distance of A in mm 11.25\nrelief distance of B in mm 8.12\nrelief distance of C in mm 4.94\nscale of photograph in 1 in 13123.0\n"
+      }
+     ],
+     "prompt_number": 3
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 6.8,Page 300"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,sqrt,acos,asin,atan,cos,sin,tan\nf=0.1524;#focal length\nS=0.08251/1000;#scale\n\n#calculation\nH=f/S;\n\n#result\nprint \"flying height in m\",round(H,3)",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "flying height in m 1847.049\n"
+      }
+     ],
+     "prompt_number": 4
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 6.9,Page 300"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,sqrt,acos,asin,atan,cos,sin,tan\nimport numpy as np\n\n#solving the quadratic polynomial in H\n#0=0.4064-365.929H-289685.07\ncoeff=[0.4064, -365.929,-289685.926];\nH=np.roots(coeff);\n\n#result\nprint \"height required in m\",round(H[0],2)",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "height required in m 1407.02\n"
+      }
+     ],
+     "prompt_number": 5
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 6.10,Page 309"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,sqrt,acos,asin,atan,cos,sin,tan\nS=1.0/10000;#scale\nA=500.0;#area\npw=0.3;\nl=0.23;\nw=0.23;\n\n#calculation\na=(1-0.6)*(1-pw)*l*w/S**2/1000/1000;\nN=A/a;\n\n#result\nprint \"no. of photographs taken\",round(N)",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "no. of photographs taken 338.0\n"
+      }
+     ],
+     "prompt_number": 2
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 6.11,Page 310"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,sqrt,acos,asin,atan,cos,sin,tan\nL=25.0e3;\nk=0.23e4;#l/s=w/s;\npl=0.6;\npw=0.3;\nW=20.0e3;\n\n#calculation\nN=((L/((1-pl)*k)+1))*((W/((1-pw)*k)+1)+1);\n\n#result\nprint \"no. of photographs taken\",round(N)",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "no. of photographs taken 406.0\n"
+      }
+     ],
+     "prompt_number": 7
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 6.12,Page 310"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,sqrt,acos,asin,atan,cos,sin,tan\nf=0.1524;#focal length\nS=1.0/10000;#scale\npw=0.3;#side lap\nw=0.23;#format width\npl=0.6;\nl=0.23;\n\n#calculation\nW=(1-pw)/S*w;\nH=f/S+300;\nN2=30/W+1;\nN2=round(N2)\nL=(1-pl)*1/S*l/1000;\nT=3600*L/240.0;\nAd=T*240e3/60.0/60.0;#adjusted ground distance\nN1=40.0e3/Ad+1;\nN1=round(N1)\nN=N1*N2;\n\n#result\nprint \"height over datum in m\",H\nprint \"no. of flight strips\",round(N2-1)\nprint \"length of each photograph cover in km\",round(L,3)\nprint \"exposure time in s\",round(T)\nprint \"no. of photographs taken\",round(N)",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "height over datum in m 1824.0\nno. of flight strips 0.0\nlength of each photograph cover in km 0.92\nexposure time in s 14.0\nno. of photographs taken 44.0\n"
+      }
+     ],
+     "prompt_number": 3
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 6.12b,Page 317"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,sqrt,acos,asin,atan,cos,sin,tan\nt=3.0/180*pi;\nya=82.25;\nxa=-62.45;\ns=220;\nf=152.4;#focal length\nH=2500.0e3;\nh=500.0e3;\n\n#calculation\ntheta=s-180;\nya_dash=xa*sin(theta*pi/180)+ya*cos(theta*pi/180)+f*tan(t)\nS=(f/cos(t)-ya_dash*sin(t))/(H-h);\n\n#result\nprint  \"scale of photograph in 1 in\",round(1/S)",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "scale of photograph in 1 in 13246.0\n"
+      }
+     ],
+     "prompt_number": 4
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 6.13,Page 319"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,sqrt,acos,asin,atan,cos,sin,tan\nt=3*pi/180;\nxa=-62.45;\nxb=78.25;\nf=152.4;#focal length\nH=2500.0;#actual height\nhb=800#height B\nha=500.0;#height A\nya=82.25;\nyb=-41.15;\ns=220.0;\n\n#calculation\ntheta=s-180;\nya1=xa*sin(theta*pi/180)+ya*cos(theta*pi/180)+f*tan(t); # ya'\nxa1=xa*cos(theta*pi/180)-ya*sin(theta*pi/180); #xa'\nxb1=xb*cos(theta*pi/180)-yb*sin(theta*pi/180); #xb'\nyb1=xb*sin(theta*pi/180)+yb*cos(theta*pi/180)+f*tan(t); # yb'\nXa=xa1*(H-ha)/(f/cos(t)-ya1*sin(t));\nXb=xb1*(H-hb)/(f/cos(t)-yb1*sin(t));\nYa=ya1*cos(t)*(H-ha)/(f/cos(t)-ya1*sin(t));\nYb=yb1*cos(t)*(H-hb)/(f/cos(t)-yb1*sin(t));\nAB=sqrt((Xb-Xa)**2+(Yb-Ya)**2);\n\n#result\nprint \"distance of AB in m\",round(AB,3)\n",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "distance of AB in m 2307.753\n -100.708756369  78.25  82.25  -41.15  0.642787609687\n"
+      }
+     ],
+     "prompt_number": 12
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 6.14,Page 324"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,sqrt,acos,asin,atan,cos,sin,tan\nri=95.0;\nf=152.4;\nt=3*pi/180;\nl=50*pi/180;\n\n#calculation\ndt=ri**2*sin(t)*cos(l)**2/(f-ri*sin(t)*cos(l));\n                           \n#result\nprint \"tilt displacement of the image in mm\",round(dt,2)",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "tilt displacement of the image in mm 1.31\n"
+      }
+     ],
+     "prompt_number": 10
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 6.15,Page 351"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,sqrt,acos,asin,atan,cos,sin,tan\nd=230.0;#square side\nf=152.4#focal length\npl=0.6;\n\n#calculation\nk=(1-pl)*d/f;\nV=k/0.15;\n\n#result\nprint \"vertical exaggeration is\",round(V,2)",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "vertical exaggeration is 4.02\n"
+      }
+     ],
+     "prompt_number": 1
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 6.16,Page 360"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,sqrt,acos,asin,atan,cos,sin,tan\nxa=51.23;\nxb=91.48;\nya=48.33;\nyb=-51.63;\nf=152.4;#focal length\nB=425.0;#actual height\nhb=842.86#height B\nha=820.97;#height A\nr1=10.42;\nr2=9.67;\nb1=89.12;#b'\nb=89.43;\nra=11.62;\nrb=14.53;\n\n#calculation\nC=0.5*((b1-r1)+(b-r2))\npa=C+ra;\npb=C+rb;\nXa=B*xa/pa;\nXb=xb*B/pb;\nYa=ya*B/pa;\nYb=yb*B/pb;\nAB=sqrt((Xb-Xa)**2+(Yb-Ya)**2);\n\n#result\nprint \"distance of AB in m\",round(AB,3)",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "distance of AB in m 492.28\n"
+      }
+     ],
+     "prompt_number": 13
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 6.17,Page 363"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,sqrt,acos,asin,atan,cos,sin,tan\nC=79.0;\nra=11.42;#elevarion in image\nrb=15.65;#elevarion in image\nhb=651;#height of B\nH=1500;#height\n\n#calculation\ndelp=ra-rb;#pa=ra+c and pb=rb+c so ra-rb=pa-pb\npa=ra+C;\nha=hb+delp/pa*(H-hb);\n\n#result\nprint \"height of A in m\",round(ha,3)",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "height of A in m 611.282\n"
+      }
+     ],
+     "prompt_number": 11
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 6.18,Page 364"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,sqrt,acos,asin,atan,cos,sin,tan\nB=741.0;\nf=152.4;\npa=94.32;\nha=325;\n\n#calculation\nH=ha+B*f/pa;\n\n#result\nprint \"height in m\",round(H,3)",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "height in m 1522.29\n"
+      }
+     ],
+     "prompt_number": 12
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 6.19,Page 364"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,sqrt,acos,asin,atan,cos,sin,tan\nH=1632.0;\nf=152.4;#focal length\npa=82.75;\nha=283;\n\n#calculation\nB=pa/f*(H-ha);\n\n#result\nprint \"width of air base in m\",round(B,3)",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "width of air base in m 732.479\n"
+      }
+     ],
+     "prompt_number": 13
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 6.20,Page 377"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,sqrt,acos,asin,atan,cos,sin,tan\nalpha=50.0;\nbeta=46.0;\nf=300.0;\nxa=24.0;\nxb=30.0;\nbeta=46.0;\n\n#calculation\ndela=xa/f;\ndelb=xb/f;\nA=alpha+dela*180/pi; #angle A\nB=beta-delb*180/pi; #angle B\nD=180-A-B;\nAD=1300.0*sin(B*pi/180)/sin(D*pi/180);\nY=6/(sqrt(xa**2+f**2))*AD;\nRD=60.12+Y;\n\n#result\nprint \"distance of AD in m\",round(AD,2)\nprint \"RL of D in m\",round(RD,2)",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "distance of AD in m 843.34\nRL of D in m 76.93\n"
+      }
+     ],
+     "prompt_number": 14
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 6.21,Page 378"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,sqrt,acos,asin,atan,cos,sin,tan\nf=152.4;\nL=120;#length\nx1=40.0;\nx2=-90.0;\n\n#calculation\nX=f*L/(x1-x2);\nY=L*x1/(x1-x2);\nh=X*(30-20)/f;\n\n#result\nprint \"the coordinates of D in m is X=\",round(X,2),\"Y =\",round(Y,2);\nprint \"elevation of D in m\",round(h,2)",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "the coordinates of D in m is X= 140.68 Y = 36.92\nelevation of D in m 9.23\n"
+      }
+     ],
+     "prompt_number": 15
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 6.22,Page 380"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,sqrt,acos,asin,atan,cos,sin,tan\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    sd=round(sd,2)\n    return [d, m, sd]\nf=150.4;\nxc=-32.43;\nxd=9.52;\n\n#calculation\nthc=atan(xc/f);\nthd=atan(xd/f);\nth=thd-thc;\nth=th*180/pi;\nAz=325+15.0/60+th;\nAz=deg_to_dms(Az);\n\n#result\nprint \"Azimuth of D in deg,min,sec respectively\",Az",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "Azimuth of D in deg,min,sec respectively [341, 2, 23.9]\n"
+      }
+     ],
+     "prompt_number": 16
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 6.23,Page 382"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,sqrt,acos,asin,atan,cos,sin,tan\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    sd=round(sd,2)\n    return [d, m, sd]\nBC=66.0;\nAC=81.6;\nxb=3.0;\nya=1.25;\nxa=3.3;\ntheta=23+43.0/60;\n\n#calcualtions\nf=(xa+xb)/2/tan(theta*pi/180)+sqrt((xa+xb)**2/4/(tan(theta*pi/180))**2+xa*xb);\naa=atan(ya/sqrt(xa**2+f**2))\nVa=AC*tan(aa);\nab=atan(-1.87/sqrt(xa**2+f**2));\nVb=-BC*tan(ab);\n\n#result\nprint \"focal length in cm\",round(f,2)\nprint \"horizontal distance in m\",round(Vb+Va,2)\n",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "focal length in cm 15.0\nhorizontal distance in m 14.68\n"
+      }
+     ],
+     "prompt_number": 2
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 6.24,Page 383"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,sqrt,acos,asin,atan,cos,sin,tan\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    sd=round(sd,2)\n    return [d, m, sd]\nEab=300.0;#average elevation\nf=152.4;\nxa=28.4;\nxb=-22.5;\nya=24.5;\nyb=38.4;\nHa=2322.0;\nha=400.0;\nhb=200.0;\nab=61.05;\nAB=810;\n\n#calculation\nHa=300+AB/ab*f;\nXa=round((Ha-ha)/f*xa,2);\nXb=round((Ha-ha)/f*xb,2);\nYa=round((Ha-hb)/f*ya,2);\nYb=round((Ha-hb)/f*yb,2);\nAB=sqrt((Xa-Xb)**2+(Ya-Yb)**2);\nH=300+810/AB*(Ha-Eab);\nXa=(H-ha)/f*xa;\nXb=(H-ha)/f*xb;\nYa=(H-hb)/f*ya;\nYb=(H-hb)/f*yb;\nAB1=sqrt((Xa-Xb)**2+(Ya-Yb)**2);\n\n#result\nprint \"Xb is calculated wrong in the book that resulted in the error\"\nprint \"length AB in m\", round(AB,2)\nprint \"corrected length AB in m\", round(AB1,2)\nprint \"flying height in m\",round(H,3)\n\n",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "length AB in m 670.47\ncorrected length AB in m 816.12\nflying height in m 2742.807\n"
+      }
+     ],
+     "prompt_number": 3
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 6.25,Page 386"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,sqrt,acos,asin,atan,cos,sin,tan\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    sd=round(sd,2)\n    return [d, m, sd]\nAB=300.0;\nab=102.4;\nf=152.4;#focal length\nhab=320.0;\nd=7.8;\nr=75.4;\n\nH=hab+AB/ab*f;\nh=d*H/r;\n\n#result\nprint \"height difference in m\",round(h,2)",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "height difference in m 79.29\n"
+      }
+     ],
+     "prompt_number": 12
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 6.26,Page 386"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,sqrt,acos,asin,atan,cos,sin,tan\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    sd=round(sd,2)\n    return [d, m, sd]\nf=152.4;\nb=74.25;\nht=100.0;\nH=700.0;#flying height\n\n#calculation\nB=b*H/f;\npb=f*B/H;\npt=f*B/(H-ht);\ndelp=pt-pb;\nht=delp/pt*(H);\n\n#result\nprint \"error due to parallax in mm\",round(delp,2)\nprint \"height of chimney in m\",round(ht,2)",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "error due to parallax in mm 12.38\nheight of chimney in m 100.0\n"
+      }
+     ],
+     "prompt_number": 14
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 6.27,Page 387"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,sqrt,acos,asin,atan,cos,sin,tan\ndef deg_to_dms(deg):\n    d = int(deg)\n    md = abs(deg - d) * 60\n    m = int(md)\n    sd = (md - m) * 60\n    sd=round(sd,2)\n    return [d, m, sd]\nB=180.0;\nf=120.0;\npa=54.32\npb=46.35;\n\n#calculation\ndelH=B*f/pa/pb*(pa-pb);\n\n#result\nprint \"height difference in m\",round(delH,2)",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "height difference in m 68.38\n"
+      }
+     ],
+     "prompt_number": 17
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": "Example 6.28,Page 387"
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": "#initialisation of variable\nfrom math import pi,sqrt,acos,asin,atan,cos,sin,tan\nL1=30000.0;\npl=0.6;\nk=12000.0*0.2;#=l/S and w/S\npw=0.3;\nW1=24000;\n\n#calculation\nN=round(((L1/((1-pl)*k)+1)+1))*round(((W1/((1-pw)*k)+1)+1));\nNf=N/33-1;#flight strips\ngd=(1-pl)*k;#grounf distance\nI=gd/(200e3)*60.0*60.0;#exposure interval\nad=round(I)/60.0/60*200e3;#actual distance\n\n#result\nprint \"no. of photographs taken\",round(N)\nprint \"no. of flight strips\",Nf\nprint \"ground distance in m\",round(gd,2)\nprint \"exposure interval in s\", round(I)\nprint \"actual distance in m\",round(ad,2)",
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": "no. of photographs taken 528.0\nno. of flight strips 15.0\nground distance in m 960.0\nexposure interval in s 17.0\nactual distance in m 944.44\n"
+      }
+     ],
+     "prompt_number": 35
+    }
+   ],
+   "metadata": {}
+  }
+ ]
+}
\ No newline at end of file
diff --git a/Surveying_Volume_3/README.txt b/Surveying_Volume_3/README.txt
new file mode 100755
index 00000000..2c27e6c8
--- /dev/null
+++ b/Surveying_Volume_3/README.txt
@@ -0,0 +1,10 @@
+Contributed By: Tarun Kumar Das
+Course: btech
+College/Institute/Organization: College of Engineering
+Department/Designation: Industrial Engineering
+Book Title: Surveying Volume 3
+Author: A K Arora
+Publisher: Lakshmi Publications, Chennai
+Year of publication: 2011
+Isbn: 9788189401276
+Edition: 1
\ No newline at end of file
diff --git a/Surveying_Volume_3/screenshots/chapter1.png b/Surveying_Volume_3/screenshots/chapter1.png
new file mode 100755
index 00000000..14135a76
--- /dev/null
+++ b/Surveying_Volume_3/screenshots/chapter1.png
diff --git a/Surveying_Volume_3/screenshots/chapter4.png b/Surveying_Volume_3/screenshots/chapter4.png
new file mode 100755
index 00000000..ad0a4bc9
--- /dev/null
+++ b/Surveying_Volume_3/screenshots/chapter4.png
diff --git a/Surveying_Volume_3/screenshots/chapter5.png b/Surveying_Volume_3/screenshots/chapter5.png
new file mode 100755
index 00000000..bd0c856e
--- /dev/null
+++ b/Surveying_Volume_3/screenshots/chapter5.png
diff --git a/Thermodynamics_by_F_P_Durham/README.txt b/Thermodynamics_by_F_P_Durham/README.txt
new file mode 100755
index 00000000..f88f2e55
--- /dev/null
+++ b/Thermodynamics_by_F_P_Durham/README.txt
@@ -0,0 +1,10 @@
+Contributed By: Pratik Tanna
+Course: bca
+College/Institute/Organization: CZMG BCA, Jamnagar
+Department/Designation: BCA
+Book Title: Thermodynamics by F P Durham
+Author: F. P. Durham
+Publisher: Prentice Hall
+Year of publication: 1959
+Isbn: 1105809269
+Edition: 2nd
\ No newline at end of file
diff --git a/Thermodynamics_by_F_P_Durham/chapter10.ipynb b/Thermodynamics_by_F_P_Durham/chapter10.ipynb
new file mode 100755
index 00000000..c9d863da
--- /dev/null
+++ b/Thermodynamics_by_F_P_Durham/chapter10.ipynb
@@ -0,0 +1,164 @@
+{
+ "metadata": {
+  "name": "",
+  "signature": "sha256:290fc441b8b16bf79982880c80bb6a81fed30d12de1c6a3c7f5a66a567e435bd"
+ },
+ "nbformat": 3,
+ "nbformat_minor": 0,
+ "worksheets": [
+  {
+   "cells": [
+    {
+     "cell_type": "heading",
+     "level": 1,
+     "metadata": {},
+     "source": [
+      "Chapter 10: Refrigeration"
+     ]
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 10.1, page no. 193"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "#initialization\n",
+      "capacity = 5.0                 #tons\n",
+      "hp = 10.0                       #hp\n",
+      "\n",
+      "#calculation\n",
+      "beta = (778*3.33*capacity)/(hp*550)\n",
+      "\n",
+      "#result\n",
+      "print \"Coefficient of performance  = \", round(beta, 2)"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Coefficient of performance  =  2.36\n"
+       ]
+      }
+     ],
+     "prompt_number": 6
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 10.2, page no. 197"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "#initialization\n",
+      "P1 = 30.0                   #lb/in^2\n",
+      "P2 = 200.0                  #lb/in^2\n",
+      "capacity = 3.0              #tons\n",
+      "\n",
+      "#calculation\n",
+      "#From the pressure enthalpy chart\n",
+      "Tt1 =  -1                   #F\n",
+      "st1 = 1.34\n",
+      "ht1 = 612.0\n",
+      "ht2 = 733.0\n",
+      "ht3 = 141.0\n",
+      "ht4 = 141.0\n",
+      "WbyJ = ht2-ht1\n",
+      "Q = ht1-ht3\n",
+      "beta = Q/WbyJ\n",
+      "Qdot = capacity*3.33\n",
+      "wdot = Qdot/Q\n",
+      "Power = wdot*778*WbyJ\n",
+      "Power = Power/550.0\n",
+      "\n",
+      "#result\n",
+      "print \"Coefficient of performance  =  \", round(beta, 2)\n",
+      "print \"Evarator temperature  =  %d F\" %Tt1\n",
+      "print \"Power required  =  %.2f hp\" %Power\n"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Coefficient of performance  =   3.89\n",
+        "Evarator temperature  =  -1 F\n",
+        "Power required  =  3.63 hp\n"
+       ]
+      }
+     ],
+     "prompt_number": 13
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 10.3, page no. 200"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "#initialization\n",
+      "P1 = 14.0                   #lb/in^2\n",
+      "P2 = 60.0                   #lb/in^2\n",
+      "Tt1 = 80+460.0              #R\n",
+      "Tt4 = -20+460.0             #R\n",
+      "m = 30.0                    #lbm/sec\n",
+      "cp = 0.24\n",
+      "\n",
+      "#calculation\n",
+      "Tt2 = round(Tt1*(P2/P1)**(0.286))\n",
+      "Tt3 = round(Tt4*(P2/P1)**(0.286))\n",
+      "WbyJ1 = cp*(Tt2-Tt1)\n",
+      "WbyJ2 = cp*(Tt3-Tt4)\n",
+      "Q = cp*(Tt1-Tt4)\n",
+      "beta = Q/(WbyJ1-WbyJ2)\n",
+      "Power = (m*778)*(WbyJ1-WbyJ2)\n",
+      "Wdot = Power/550.0\n",
+      "\n",
+      "#result\n",
+      "print \"Coefficient of performance  =  %.3f\" %beta\n",
+      "print \"Net power  =  %d hp\" %Wdot\n",
+      "\n",
+      "#difference in answer due to rounding of in Python"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Coefficient of performance  =  1.923\n",
+        "Net power  =  529 hp\n"
+       ]
+      }
+     ],
+     "prompt_number": 24
+    }
+   ],
+   "metadata": {}
+  }
+ ]
+}
\ No newline at end of file
diff --git a/Thermodynamics_by_F_P_Durham/chapter11.ipynb b/Thermodynamics_by_F_P_Durham/chapter11.ipynb
new file mode 100755
index 00000000..ddbbdc4c
--- /dev/null
+++ b/Thermodynamics_by_F_P_Durham/chapter11.ipynb
@@ -0,0 +1,484 @@
+{
+ "metadata": {
+  "name": "",
+  "signature": "sha256:1bc460ef0aed5b06b0770ef04462064cc24e898eb90d5d0126bc2216d06cd7e0"
+ },
+ "nbformat": 3,
+ "nbformat_minor": 0,
+ "worksheets": [
+  {
+   "cells": [
+    {
+     "cell_type": "heading",
+     "level": 1,
+     "metadata": {},
+     "source": [
+      "Chapter 11: Nozzels & Jet Propulsion"
+     ]
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 11.1, page no. 207"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "import math\n",
+      "\n",
+      "\n",
+      "#initialization\n",
+      "P1 = 100.0                  #lb/in^2\n",
+      "P2 = 14.7                   #lb/in^2\n",
+      "T1 = 600+460.0              #R\n",
+      "T2 = 300+460.0              #R\n",
+      "area = 1.0                  #in^2\n",
+      "\n",
+      "#calculation\n",
+      "#From steam tables\n",
+      "ht1 = 1329.1 \n",
+      "h2 = 1192.8\n",
+      "v2 = 30.53\n",
+      "Vel = math.sqrt(2*32.2*778.0*(ht1-h2))\n",
+      "\n",
+      "wdot = area*Vel/(144*v2)\n",
+      "\n",
+      "\n",
+      "#result\n",
+      "print \"Exit velocity  =  %d ft/sec\" %Vel\n",
+      "print \"Mass flow rate  =  %.3f lbm/sec\" %wdot\n",
+      "#difference in exit velocity due to rounding off in Python"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Exit velocity  =  2613 ft/sec\n",
+        "Mass flow rate  =  0.594 lbm/sec\n"
+       ]
+      }
+     ],
+     "prompt_number": 7
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 11.2, page no. 210"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "import math\n",
+      "\n",
+      "#initialization\n",
+      "Pt1 = 100.0                 #lb/in^2\n",
+      "P2 = 15.0                   #lb/in^2\n",
+      "A = 1.0                     #in^2\n",
+      "T = 500+460.0               #F\n",
+      "gamma = 1.4\n",
+      "\n",
+      "#calculation\n",
+      "Pratio = P2/Pt1\n",
+      "r1 = (P2/Pt1)**((gamma-1)/gamma)\n",
+      "r2 = (P2/Pt1)**(2/gamma)\n",
+      "r3 = (P2/Pt1)**((gamma+1)/gamma)\n",
+      "V2 = math.sqrt(2*gamma*32.2*53.3*T*(1-r1)/(gamma-1))\n",
+      "wdot = A*Pt1*math.sqrt(2*gamma*(r2-r3)/(gamma-1)) /(math.sqrt(53.3*T/32.2))\n",
+      "\n",
+      "#result\n",
+      "print \"Exit velocity  =  %d ft/sec\" %V2\n",
+      "print \"Mass flow rate  = \", round(wdot, 3), \"lbm/sec\"\n"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Exit velocity  =  2196 ft/sec\n",
+        "Mass flow rate  =  1.107 lbm/sec\n"
+       ]
+      }
+     ],
+     "prompt_number": 2
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 11.3, page no. 212"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "import math\n",
+      "\n",
+      "#initialization\n",
+      "Pt1 = 100.0                     #lb/in^2\n",
+      "Tt1 = 960.0                     #RP2 = 15 #lb/in^2\n",
+      "wdot = 1.13                     #lbm/sec\n",
+      "gamma = 1.4\n",
+      "\n",
+      "#calculation\n",
+      "Pstar = Pt1*(2/(1+gamma))**(gamma/(gamma-1))\n",
+      "Tstar = Tt1*(2/(1+gamma))\n",
+      "Vstar = math.sqrt(gamma*32.2*53.3*Tstar)\n",
+      "vstar = 53.3*Tstar/(144*Pstar)\n",
+      "Astar = wdot*vstar*144/Vstar\n",
+      "\n",
+      "#result\n",
+      "print \"Ideal throat area  =  \", round(Astar,3), \"in^2\"\n",
+      "print \"Ideal pressure  =  \", round(Pstar, 1), \"lb/in^2\"\n",
+      "print \"Ideal temperature  =  %d R\" %Tstar\n",
+      "print \"Ideal throat specific volume  =  \", round(vstar, 1), \"ft^3/lbm\"\n"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Ideal throat area  =   0.658 in^2\n",
+        "Ideal pressure  =   52.8 lb/in^2\n",
+        "Ideal temperature  =  800 R\n",
+        "Ideal throat specific volume  =   5.6 ft^3/lbm\n"
+       ]
+      }
+     ],
+     "prompt_number": 7
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 11.4, page no. 215"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "import math\n",
+      "\n",
+      "\n",
+      "#initialization\n",
+      "ht1 = 1329.1\n",
+      "st1 = 1.7581\n",
+      "h2s = 1151.4\n",
+      "s2s = 1.7581\n",
+      "\n",
+      "#calculation\n",
+      "eta = math.sqrt((ht1-1192.8)/(ht1-h2s))\n",
+      "\n",
+      "#result\n",
+      "print \"efficiency  = \", round(eta, 2)\n"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "efficiency  =  0.88\n"
+       ]
+      }
+     ],
+     "prompt_number": 10
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 11.5, page no. 216"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "#initializaiton\n",
+      "v = 2200.0                      #exit velocity from ex. 11.2\n",
+      "p = 15.0                        #exit pressure\n",
+      "n_eta = 0.95                    #nozzle efficiency 95%\n",
+      "t2 = 598.0\n",
+      "\n",
+      "#calculations\n",
+      "V2 = n_eta*v\n",
+      "v = (53.3*t2)/(144.0*p)\n",
+      "w = (1.0*V2)/(144.0*v)\n",
+      "\n",
+      "print \"Volume at exit \", round(v, 1), \"ft^3/lbm\"\n",
+      "print \"The mass flow is \", round(w, 3), \"lbm/sec\"\n",
+      "#difference in answers due to rounding off in Python, check manually"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Volume at exit  14.8 ft^3/lbm\n",
+        "The mass flow is  0.984 lbm/sec\n"
+       ]
+      }
+     ],
+     "prompt_number": 10
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 11.6, page no. 219"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "#initialization\n",
+      "v = 500.0                       #ft/sec\n",
+      "P = 14.7                        #lb/in^2\n",
+      "T = 60+460.0                    #R\n",
+      "eta = 0.85\n",
+      "cp = 0.24\n",
+      "gamma = 1.4\n",
+      "\n",
+      "#calculation\n",
+      "Pt2 = eta*P*(1+ (gamma-1)*v**2 /(2*gamma*32.2*53.3*T))**(gamma/(gamma-1))\n",
+      "Tratio = 1+(gamma-1)*v*v/(2*gamma*32.2*53.3*T)\n",
+      "Tt2 = T*Tratio\n",
+      "\n",
+      "#result\n",
+      "print \"Exit stagnation temperature   =  %d R\" %(Tt2+1)\n"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Exit stagnation temperature   =  541 R\n"
+       ]
+      }
+     ],
+     "prompt_number": 19
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 11.7, page no. 222"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "import math\n",
+      "\n",
+      "#initialization\n",
+      "P = 30.0                        #lb/in^2\n",
+      "T = 1000+460.0                  #R\n",
+      "Pd = 14.7                       #lb/in^2\n",
+      "w = 60.0                        #lbm/sec\n",
+      "eta = 0.95                      #percent\n",
+      "R = 53.3\n",
+      "gamma = 1.35\n",
+      "cp = 0.264\n",
+      "\n",
+      "#calculation\n",
+      "V2s = math.sqrt(2*gamma*32.2*53.3*T*(1-(Pd/P)**(0.259))/(gamma-1))\n",
+      "V2 = eta*V2s\n",
+      "Fn = w*(V2)/32.2\n",
+      "\n",
+      "#result\n",
+      "print \"Thrust of the engine  =  %d ft/sec\" %Fn\n",
+      "\n",
+      "#difference due to +5 in V2s calculation while sqrt"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Thrust of the engine  =  3196 ft/sec\n"
+       ]
+      }
+     ],
+     "prompt_number": 1
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 11.8, page no. 226"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "import math\n",
+      "\n",
+      "#initialization\n",
+      "v = 600.0                       #ft/sec\n",
+      "T = 60+460.0                    #R\n",
+      "P = 14.7                        #lb/in^2\n",
+      "Pratio = 6.0\n",
+      "Tin = 1540+460.0                #R\n",
+      "cp = 0.264\n",
+      "cpratio = 1.35\n",
+      "\n",
+      "#calculation\n",
+      "Pt2byP1 = (1+(cpratio-1)*v**2/(cpratio*2*32.2*53.3*T))**(3.86)\n",
+      "Pt3byP1 = Pt2byP1*Pratio\n",
+      "eta = 1-1/(Pt3byP1)**0.259\n",
+      "Tt3 = T*(Pt3byP1)**((cpratio-1)/cpratio)\n",
+      "Q = cp*(Tin-Tt3)\n",
+      "V6 = math.sqrt(eta*2*32.2*778*Q + v**2)\n",
+      "Fn = (V6-v)/32.2\n",
+      "\n",
+      "#resullts\n",
+      "print \"Thermal efficiency  = \", round(eta, 3)\n",
+      "print \"thrust per pound of air per sec  =  \", round(Fn, 1), \"lb-sec/lbm\""
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Thermal efficiency  =  0.403\n",
+        "thrust per pound of air per sec  =   59.8 lb-sec/lbm\n"
+       ]
+      }
+     ],
+     "prompt_number": 27
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 11.9, page no. 229"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "#initialization\n",
+      "V = 1000.0                      #mph\n",
+      "P = 14.7                        #lb/in^2\n",
+      "T = 60.0                        #F\n",
+      "g = 1.4\n",
+      "\n",
+      "#calculation\n",
+      "\n",
+      "V1 = V*(88/T)\n",
+      "Pratio = (1+ (g-1)*V1**2 /(2*g*32.2*53.3*(T+460)))**(g/(g-1))\n",
+      "eta = 1-1/(Pratio)**0.286\n",
+      "\n",
+      "#result\n",
+      "print \"Theoretical cycle efficiency  =  \", round(eta, 3)"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Theoretical cycle efficiency  =   0.256\n"
+       ]
+      }
+     ],
+     "prompt_number": 29
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 11.10, page no. 230"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "import math\n",
+      "\n",
+      "#initialization\n",
+      "P = 300.0                           #lb/in^2\n",
+      "P2 = 14.7                           #lb/in^2\n",
+      "T = 4540+460.0                      #R\n",
+      "w = 100.0                           #lbm/sec\n",
+      "g = 1.25\n",
+      "MW = 30.0\n",
+      "R = 1544.0\n",
+      "\n",
+      "#calculation\n",
+      "R = R/MW\n",
+      "Pratio = P2/P\n",
+      "V4 = math.sqrt(2*g*32.2*51.5*T*(1-(Pratio)**((g-1)/g))/(g-1)) \n",
+      "Fn = w*V4/32.2\n",
+      "\n",
+      "#result\n",
+      "print \"Thrust  =  %d lb\" %Fn"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Thrust  =  19031 lb\n"
+       ]
+      }
+     ],
+     "prompt_number": 30
+    }
+   ],
+   "metadata": {}
+  }
+ ]
+}
\ No newline at end of file
diff --git a/Thermodynamics_by_F_P_Durham/chapter12.ipynb b/Thermodynamics_by_F_P_Durham/chapter12.ipynb
new file mode 100755
index 00000000..466838d2
--- /dev/null
+++ b/Thermodynamics_by_F_P_Durham/chapter12.ipynb
@@ -0,0 +1,543 @@
+{
+ "metadata": {
+  "name": "",
+  "signature": "sha256:369d727c64e74475d8c5bb63540cbc246cbdecc5bfe067dfd2c4f31c8ec059a2"
+ },
+ "nbformat": 3,
+ "nbformat_minor": 0,
+ "worksheets": [
+  {
+   "cells": [
+    {
+     "cell_type": "heading",
+     "level": 1,
+     "metadata": {},
+     "source": [
+      "Chapter 12: Mixtures"
+     ]
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 12.1, page no 235"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "#initialization\n",
+      "w1 = 2 #lbm\n",
+      "w2 = 1 #lbm\n",
+      "P = 30 #lbm/in^2\n",
+      "T = 60+460 #R\n",
+      "\n",
+      "#calculation\n",
+      "R1 = 35.1\n",
+      "R2 = 55.1\n",
+      "Rm = (w1*R1+w2*R2)/(w1+w2)\n",
+      "vm = (w1+w2)*Rm*T/(144*P)\n",
+      "p1 = w1*R1*T/(144*vm)\n",
+      "p2 = w2*R2*T/(144*vm)\n",
+      "\n",
+      "#result\n",
+      "print \"Gas constant of the mixture  = \", round(Rm, 1), \"lb/in^2\"\n",
+      "print \"Volume of the mixture  =  \", round(vm, 1), \"ft^3\"\n",
+      "print \"Partial pressure of CO2  =  \", round(p1, 1), \"lb/in^2\"\n",
+      "print \"Partial pressure of N2  =  \", round(p2, 1), \"lb/in^2\""
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Gas constant of the mixture  =  41.8 lb/in^2\n",
+        "Volume of the mixture  =   15.1 ft^3\n",
+        "Partial pressure of CO2  =   16.8 lb/in^2\n",
+        "Partial pressure of N2  =   13.2 lb/in^2\n"
+       ]
+      }
+     ],
+     "prompt_number": 6
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 12.3, page no. 238"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "import scipy.integrate\n",
+      "\n",
+      "#initialization\n",
+      "cpm = 0.2523\n",
+      "Rm = 54.7\n",
+      "T1 = 60+460.0                           #R\n",
+      "T2 = 400+460.0                          #R\n",
+      "\n",
+      "#calculation\n",
+      "cvm = cpm-Rm/778.0\n",
+      "Q = cpm*(T2-T1)\n",
+      "W = Rm*(T2-T1)\n",
+      "#Rm is divided and multiplied by 778.!\n",
+      "def s(T):\n",
+      "    cp = cpm/T\n",
+      "    return cp\n",
+      "ds = scipy.integrate.quadrature(s, T1, T2)[0]\n",
+      "\n",
+      "#result\n",
+      "print \"Entropy change  = \", round(ds, 3), \"B/lbm\"\n",
+      "print \"specific work  = \", W, \"ft-lb/lbm\"\n",
+      "print \"Heat added per pound of mixture  = \", round(Q, 1), \"B/lbm\""
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Entropy change  =  0.127 B/lbm\n",
+        "specific work  =  18598.0 ft-lb/lbm\n",
+        "Heat added per pound of mixture  =  85.8 B/lbm\n"
+       ]
+      }
+     ],
+     "prompt_number": 10
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 12.4, page no. 239"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "#initialization\n",
+      "P = 14.7                        #lb/in^2\n",
+      "T = 80+460.0                    #R\n",
+      "\n",
+      "#calculation\n",
+      "#From steam tables\n",
+      "Ps = 0.5069                     #lb/in^2\n",
+      "v = 633.1                       #ft^3/lbm\n",
+      "Pair = P-Ps\n",
+      "vair = 53.3*T/(144*Pair)\n",
+      "wair = 1/(1+vair/v)\n",
+      "wwater = vair/v/(1+vair/v)\n",
+      "\n",
+      "#result\n",
+      "print \"Partial pressure of air  =  \", round(Pair, 1), \"ft^3/lbm\"\n",
+      "print \"Partial pressure of water vapor  =  \", Ps, \"ft^3/lbm\"\n",
+      "print \"Gravimetric analysis of air  =  \", round(wair, 4)\n",
+      "print \"Gravimetric analysis of water  = \", round(wwater, 4)"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Partial pressure of air  =   14.2 ft^3/lbm\n",
+        "Partial pressure of water vapor  =   0.5069 ft^3/lbm\n",
+        "Gravimetric analysis of air  =   0.9782\n",
+        "Gravimetric analysis of water  =  0.0218\n"
+       ]
+      }
+     ],
+     "prompt_number": 13
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 12.5, page no. 240"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "#initialization\n",
+      "P = 14.7                            #lb/in^2\n",
+      "T = 80+460.0                        #R\n",
+      "M = 18\n",
+      "Ps = 0.5069                         #lb/in^2\n",
+      "\n",
+      "#calculation\n",
+      "Pair = P-Ps\n",
+      "R = 1544/M\n",
+      "v = R*T/(144*Ps)\n",
+      "vair = 53.3*T/(144*Pair)\n",
+      "wair = 1/(1+vair/v)\n",
+      "wwater = vair/v/(1+vair/v)\n",
+      "\n",
+      "#result\n",
+      "print \"Partial pressure of air  =  \", round(Pair, 2), \"ft^3/lbm\"\n",
+      "print \"Specific volume = \", round(v), \"ft^3/lbm\"\n",
+      "print \"Gravimetric analysis of air  = \", round(wair, 4)\n",
+      "print \"Gravimetric analysis of water  =  \", round(wwater, 4)"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Partial pressure of air  =   14.19 ft^3/lbm\n",
+        "Specific volume =  629.0 ft^3/lbm\n",
+        "Gravimetric analysis of air  =  0.9781\n",
+        "Gravimetric analysis of water  =   0.0219\n"
+       ]
+      }
+     ],
+     "prompt_number": 17
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 12.6, page no. 242"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "#initialization\n",
+      "RH = 0.62\n",
+      "T = 80+460.0                        #R\n",
+      "\n",
+      "#calculation\n",
+      "#From stram tables\n",
+      "P = RH*0.5069\n",
+      "\n",
+      "#result\n",
+      "print \"Partial pressure of water vapor  = \", round(P, 4), \"lb/in^2\""
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Partial pressure of water vapor  =  0.3143 lb/in^2\n"
+       ]
+      }
+     ],
+     "prompt_number": 18
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exmaple 12.7, page no. 243"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "#initialization\n",
+      "P = 14.5                        #lb/in^2\n",
+      "T = 70+460.0                    #R\n",
+      "rh = 0.34\n",
+      "\n",
+      "#calculation\n",
+      "#From steam tables\n",
+      "Pg = 0.3631                     #lb/in^2\n",
+      "Pair = P-Pg\n",
+      "wratio = rh*0.622*Pg/Pair\n",
+      "\n",
+      "#result\n",
+      "print \"Specific humidity  =  %.5f lbm/lbm\" %wratio"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Specific humidity  =  0.00543 lbm/lbm\n"
+       ]
+      }
+     ],
+     "prompt_number": 6
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exmaple 12.8, page no. 244"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "#initialization\n",
+      "T = 100+460.0                       #R\n",
+      "rh = 0.6\n",
+      "\n",
+      "#calculation\n",
+      "#From steam tables\n",
+      "Pg = 0.9492                         #lb/in^2\n",
+      "Pwv = rh*Pg\n",
+      "T = 83                              #F\n",
+      "\n",
+      "#result\n",
+      "print \"Dew point is obtained from saturation pressure table and is equal to %d F\" %T"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Dew point is obtained from saturation pressure table and is equal to 83 F\n"
+       ]
+      }
+     ],
+     "prompt_number": 19
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 12.9, page no. 246"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "#initialization\n",
+      "T1 = 80+460.0                       #R\n",
+      "T2 = 90+460.0                       #R\n",
+      "P = 14.5                            #lb/in^2\n",
+      "cp = 0.24\n",
+      "\n",
+      "#calculation\n",
+      "#From steam tables\n",
+      "hg2 = 1096.6\n",
+      "hf3 = 48.02\n",
+      "Pg2 = 0.5069\n",
+      "hf2 = hf3\n",
+      "Pair = P-Pg2\n",
+      "wg2 = 0.622*Pg2/Pair\n",
+      "hgv1 = 1100.9\n",
+      "wwv1 = (cp*(T1-T2)+wg2*(hg2-hf3))/(hgv1-hf3)\n",
+      "Pg = 0.6982\n",
+      "xi = wwv1*(P-Pg)/(Pg*0.622)\n",
+      "\n",
+      "#result\n",
+      "print \"Specific humidity  =  \", round(wwv1, 4), \"lbm/lbm\"\n",
+      "print \"relative humidity  =  \", round(xi, 3)"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Specific humidity  =   0.0202 lbm/lbm\n",
+        "relative humidity  =   0.641\n"
+       ]
+      }
+     ],
+     "prompt_number": 20
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 12.10, page no. 247"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "#initialization\n",
+      "T1 = 69.0                           #F\n",
+      "T2 = 84.0                           #F\n",
+      "P = 14.7                            #lb/in^2\n",
+      "\n",
+      "#calculation\n",
+      "# from wet bulb n dry bulb temperature charts\n",
+      "sh = 82.0/7000.0\n",
+      "rh = 47.0\n",
+      "Pwv = 0.27\n",
+      "T = 62.0                            #F\n",
+      "h = 33.3\n",
+      "\n",
+      "#result\n",
+      "print \"Specific humidity  =  \", round(sh, 4), \"lbm/lbm\"\n",
+      "print \"Relative  humidity  = \" , rh, \"%\"\n",
+      "print \"Partial pressure  =  \", round(Pwv, 2), \"lb/in^2\"\n",
+      "print \"Dew point  = \", T, \"F\"\n",
+      "print \"Enthalpy per pound of air  = \", round(h, 1), \"V/lbm dry air\""
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Specific humidity  =   0.0117 lbm/lbm\n",
+        "Relative  humidity  =  47.0 %\n",
+        "Partial pressure  =   0.27 lb/in^2\n",
+        "Dew point  =  62.0 F\n",
+        "Enthalpy per pound of air  =  33.3 V/lbm dry air\n"
+       ]
+      }
+     ],
+     "prompt_number": 24
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 12.11, page no. 250"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "import math\n",
+      "\n",
+      "#initialization\n",
+      "g1 = [0.489, 100, 700, 35.1, 0.154]\n",
+      "g2 = [0.483, 15, 600, 55.2, 0.177]\n",
+      "g3 = [0.028, 30, 500, 386, 0.754]\n",
+      "\n",
+      "#calculation\n",
+      "v1 = g1[0] *g1[3] *g1[2] /(144*g1[1])\n",
+      "v2 = g2[0] *g2[3] *g2[2] /(144*g2[1])\n",
+      "v3 = g3[0] *g3[3] *g3[2] /(144*g3[1])\n",
+      "vm = v1+v2+v3\n",
+      "Tm = (g1[0] *g1[4] *g1[2] +g2[0] *g2[4] *g2[2] +g3[0] *g3[4] *g3[2])/(g1[0] *g1[4] +g2[0] *g2[4] +g3[0] *g3[4])\n",
+      "Pm = (g1[0] *g1[3] +g2[0] *g2[3] +g3[0] *g3[3]) *Tm/(vm*144)\n",
+      "ds1 = g1[0] *(g1[4] *math.log(Tm/g1[2]) +g1[3] /778.0 *math.log(vm/v1))\n",
+      "ds2 = g2[0] *(g2[4] *math.log(Tm/g2[2]) +g2[3] /778.0 *math.log(vm/v2))\n",
+      "ds3 = g3[0] *(g3[4] *math.log(Tm/g3[2]) +g3[3] /778.0 *math.log(vm/v3))\n",
+      "ds = ds1+ds2+ds3\n",
+      "\n",
+      "#result\n",
+      "print \"Pressure  =  \", round(Pm, 1), \"lb/in^2\"\n",
+      "print \"Temperature  =  \", round(Tm), \"R\"\n",
+      "print \"Entropy change  =  \", round(ds, 4), \"B/R\""
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Pressure  =   25.2 lb/in^2\n",
+        "Temperature  =   630.0 R\n",
+        "Entropy change  =   0.0914 B/R\n"
+       ]
+      }
+     ],
+     "prompt_number": 26
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 12.13, page no. 254"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "vdot1 = 8500.0         #cfm of air\n",
+      "v1 = 12.775            #from chart\n",
+      "wdot = vdot1/v1\n",
+      "\n",
+      "h2 = 20.3              #from chart\n",
+      "h1 = 13.85             #from chart\n",
+      "h4 = 29.0              #from chart\n",
+      "h3 = 20.3              #from chart\n",
+      "\n",
+      "#Part a\n",
+      "Q12 = h2 - h1\n",
+      "Q12 = wdot*Q12\n",
+      "print \"Capacity of preheater: \", round(Q12, 2), \"B/min\"\n",
+      "\n",
+      "#Part b\n",
+      "Q34 = h4 - h3\n",
+      "Q34 = wdot*Q34\n",
+      "print \"Capacity of reheater: \", round(Q34, 2), \"B/min\"\n",
+      "\n",
+      "#Part c\n",
+      "\n",
+      "w2 = 20.0/7000.0     #from chart\n",
+      "w3 = 54.0/7000.0     #from chart\n",
+      "W = w3 - w2\n",
+      "W = wdot*W\n",
+      "print \"Rate of water addition: \", round(W, 2), \"lbm/min\""
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Capacity of preheater:  4291.59 B/min\n",
+        "Capacity of reheater:  5788.65 B/min\n",
+        "Rate of water addition:  3.23 lbm/min\n"
+       ]
+      }
+     ],
+     "prompt_number": 3
+    }
+   ],
+   "metadata": {}
+  }
+ ]
+}
\ No newline at end of file
diff --git a/Thermodynamics_by_F_P_Durham/chapter13.ipynb b/Thermodynamics_by_F_P_Durham/chapter13.ipynb
new file mode 100755
index 00000000..134029ab
--- /dev/null
+++ b/Thermodynamics_by_F_P_Durham/chapter13.ipynb
@@ -0,0 +1,302 @@
+{
+ "metadata": {
+  "name": "",
+  "signature": "sha256:9400ac9019314c4e9a568a522343f0bdbb2a3d098bb24add69a9bd20d9589ad0"
+ },
+ "nbformat": 3,
+ "nbformat_minor": 0,
+ "worksheets": [
+  {
+   "cells": [
+    {
+     "cell_type": "heading",
+     "level": 1,
+     "metadata": {},
+     "source": [
+      "Chapter 13: Gas Dynamics"
+     ]
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 13.1, page no. 259"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "import math\n",
+      "\n",
+      "#initialization\n",
+      "v = 2000.0                      #ft/sec\n",
+      "P = 14.7                        #lb/in^2\n",
+      "g = 1.4\n",
+      "T = 10+460.0                    #R\n",
+      "\n",
+      "#calculation\n",
+      "c = math.sqrt(g*32.2*53.3*T)\n",
+      "Nm = v/c\n",
+      "Tratio = 1+ (g-1)/2 *Nm**2\n",
+      "Tt = Tratio*T\n",
+      "Pratio = (Tratio)**(g/(g-1))\n",
+      "Pt = Pratio*P\n",
+      "\n",
+      "#result\n",
+      "print \"Stagnation temperature  =  %d R\" %Tt\n",
+      "print \"Stagnation pressure  =  \", round(Pt, 1), \"lb/in^2\""
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Stagnation temperature  =  802 R\n",
+        "Stagnation pressure  =   95.8 lb/in^2\n"
+       ]
+      }
+     ],
+     "prompt_number": 2
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 13.2, page no. 261"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "import math\n",
+      "\n",
+      "#initialization\n",
+      "A = 0.3                         #ft^2\n",
+      "P = 30.0                        #lb/in^2\n",
+      "T = 160+460.0                   #R\n",
+      "Mn = 0.82\n",
+      "g = 1.4\n",
+      "\n",
+      "#calculation\n",
+      "w = A*144*P*math.sqrt(g*32.2) *Mn*(1+ (g-1)/2.0 *(Mn)**2)**(-3)/math.sqrt(53.3*T)\n",
+      "\n",
+      "#result\n",
+      "print \"Mass flow  = \", round(w, 1), \"lbm/sec\""
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Mass flow  =  26.9 lbm/sec\n"
+       ]
+      }
+     ],
+     "prompt_number": 3
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 13.3, page no. 263"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "import math\n",
+      "\n",
+      "#initialization\n",
+      "Mn = 3.0\n",
+      "Mni = 0.2\n",
+      "w = 10.0                        #lbm/sec\n",
+      "g = 1.4\n",
+      "P = 200.0                       #lb/in^2\n",
+      "T = 400+460.0                   #R\n",
+      "\n",
+      "#calculation\n",
+      "Astar = w*math.sqrt(53.3*T) *((g+1)/2)**3 /(P*math.sqrt(g*32.2))\n",
+      "A1ratio = (2.0/(g+1) + (g-1)*Mni**2 /(g+1))**3 /Mni\n",
+      "A1 = A1ratio*Astar\n",
+      "A2ratio = (2.0/(g+1) + (g-1)*Mn**2 /(g+1))**3 /Mn\n",
+      "A2 = A2ratio*Astar\n",
+      "Pexit = P/(1+ Mni*Mn**2)**(g/(g-1))\n",
+      "\n",
+      "#result\n",
+      "print \"Throat Area  =  \", round(Astar, 2), \"in^2\"\n",
+      "print \"Inlet Area  = \", round(A1, 2), \"in^2\"\n",
+      "print \"Exit Area  = \", round(A2, 2), \"in^2\"\n",
+      "print \"Exit pressure  = \", round(Pexit, 2), \"lb/in^2\""
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Throat Area  =   2.76 in^2\n",
+        "Inlet Area  =  8.16 in^2\n",
+        "Exit Area  =  11.67 in^2\n",
+        "Exit pressure  =  5.44 lb/in^2\n"
+       ]
+      }
+     ],
+     "prompt_number": 4
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 13.4, page no. 266"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "import math\n",
+      "\n",
+      "#initialization\n",
+      "Pi = 750.0                  #lb/in^2\n",
+      "g = 1.25\n",
+      "TA = 2.0                    #in^2\n",
+      "r = 3.0\n",
+      "\n",
+      "#calculation\n",
+      "Fstar = round(((g+1)*(2.0/(g+1))**5 *TA*750))\n",
+      "Me = 2.45\n",
+      "Fratio = round(((1+g*Me**2)/(Me*(math.sqrt(4.5+ (g**2 -1)*Me**2)))), 3)\n",
+      "F2 = Fratio*Fstar\n",
+      "Pratio = (1+ 0.2*Me**2)**5\n",
+      "Fnstar = Fratio-((g+1)/2.0)**5 *r/(Pratio*2.25)\n",
+      "Fn = Fnstar*Fstar\n",
+      "\n",
+      "#result\n",
+      "print \"Internal rocket thrust  =  %d lb\" %F2 #answer in textbook is wrong\n",
+      "print \"External thrust  =  %d lb\" %Fn #answer in textbook is wrong"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Internal rocket thrust  =  2316 lb\n",
+        "External thrust  =  2229 lb\n"
+       ]
+      }
+     ],
+     "prompt_number": 13
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 13.5, page no. 270"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "#initialization\n",
+      "Tt2 = 1620+460 #R\n",
+      "Tt1 = 60+460 #R\n",
+      "Mi = 0.2\n",
+      "P = 40 #lb/in^2\n",
+      "g = 1.35\n",
+      "\n",
+      "#calculation\n",
+      "Tratio = Tt2/Tt1\n",
+      "#From figure\n",
+      "fM = 4*0.036\n",
+      "NM2 = 0.49\n",
+      "Pratio = 0.98/0.885\n",
+      "Pt2 = P/Pratio\n",
+      "\n",
+      "#result\n",
+      "print \"Final stagnation pressure  =  \", round(Pt2, 1), \"lb/in^2\"\n",
+      "print \"Final mach number  = \", round(fM, 3)"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Final stagnation pressure  =   36.1 lb/in^2\n",
+        "Final mach number  =  0.144\n"
+       ]
+      }
+     ],
+     "prompt_number": 16
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 13.6, page no. 273"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "#initialization\n",
+      "M = 0.4\n",
+      "l = 10.0                            #ft\n",
+      "dia =  3.0                          #in\n",
+      "P = 50.0                            #lb/in^2\n",
+      "ff = 0.008\n",
+      "T = 100+460.0                       #R\n",
+      "\n",
+      "#calculation\n",
+      "constant =  4*ff*l/dia\n",
+      "exitM = 2.9-constant\n",
+      "Nm2 = 0.5\n",
+      "Ptratio = 2.73/2.3\n",
+      "Pt2 = P/Ptratio\n",
+      "\n",
+      "#result\n",
+      "print \"Exit total pressure  =  \", round(Pt2, 1), \"lb/in^2\""
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Exit total pressure  =   42.1 lb/in^2\n"
+       ]
+      }
+     ],
+     "prompt_number": 17
+    }
+   ],
+   "metadata": {}
+  }
+ ]
+}
\ No newline at end of file
diff --git a/Thermodynamics_by_F_P_Durham/chapter14.ipynb b/Thermodynamics_by_F_P_Durham/chapter14.ipynb
new file mode 100755
index 00000000..e037e77a
--- /dev/null
+++ b/Thermodynamics_by_F_P_Durham/chapter14.ipynb
@@ -0,0 +1,383 @@
+{
+ "metadata": {
+  "name": "",
+  "signature": "sha256:e1f2ab4731e8126f69d8554acbb321ab940bce50cce33579f99b691416bd49a5"
+ },
+ "nbformat": 3,
+ "nbformat_minor": 0,
+ "worksheets": [
+  {
+   "cells": [
+    {
+     "cell_type": "heading",
+     "level": 1,
+     "metadata": {},
+     "source": [
+      "Chapter 14: Heat Transfer"
+     ]
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 14.1, page no. 279"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "#initialization\n",
+      "T = 50.0                        #F\n",
+      "Q = 3.9                         #B/hr-ft^2\n",
+      "\n",
+      "#calculation\n",
+      "#From table 14.1\n",
+      "k = 0.026                       #B/hr-ft-F\n",
+      "dx = k*T/Q\n",
+      "\n",
+      "#result\n",
+      "print \"Required thickness  =  ft\", round(dx, 3), \"lb/in^2\""
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Required thickness  =  ft 0.333 lb/in^2\n"
+       ]
+      }
+     ],
+     "prompt_number": 2
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 14.2, page no. 281"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "#initialization\n",
+      "x1 = 1.0                        #in\n",
+      "x2 = 4.0                        #in\n",
+      "T1 = 85.0                       #F\n",
+      "T2 = 30.0                       #F\n",
+      "\n",
+      "#calculation\n",
+      "QbyA = 12*(T1-T2)/(x1/0.3 + x2/0.026)\n",
+      "\n",
+      "#result\n",
+      "print \"Rate of heat flow  = \", round(QbyA, 1), \"B/r-ft^2-F\""
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Rate of heat flow  =  4.2 B/r-ft^2-F\n"
+       ]
+      }
+     ],
+     "prompt_number": 3
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 14.3, page no. 283"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "import math\n",
+      "\n",
+      "#initialization\n",
+      "L = 6.5                         #in\n",
+      "thick = 1.0                     #in\n",
+      "k = 0.06                        #B/hr-ft-F\n",
+      "T1 = 350.0                      #F\n",
+      "T2 = 110.0                      #F\n",
+      "\n",
+      "#calculation\n",
+      "QbyL = 2*math.pi*k*(T1-T2)/math.log(1+2/L)\n",
+      "\n",
+      "#result\n",
+      "print \"heat flow  =  %d B/hr-ft\" %QbyL"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "heat flow  =  337 B/hr-ft\n"
+       ]
+      }
+     ],
+     "prompt_number": 4
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 14.4, page no. 283"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "import math\n",
+      "\n",
+      "#initialization\n",
+      "t = 0.25                        #in\n",
+      "dia = 5.5                       #in\n",
+      "t2 = 0.6                        #in\n",
+      "To = 100.0                      #F\n",
+      "kp = 34.5                       #B/hr-ft-F\n",
+      "ki = 0.05                       #B/hr-ft-F\n",
+      "l = 10.0                        #ft\n",
+      "Q = 2000.0                      #B/hr\n",
+      "\n",
+      "#calculation\n",
+      "dT = Q*(1/kp *math.log(1+ 2*t/dia) + 1/ki *math.log(1 + 4*t/(dia+2*t)))/(2*math.pi*l)\n",
+      "T1 = dT+To\n",
+      "\n",
+      "#result\n",
+      "print \"Inner surface temperature of the pipe  = \", round(T1, 1), \"F\""
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Inner surface temperature of the pipe  =  198.2 F\n"
+       ]
+      }
+     ],
+     "prompt_number": 6
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 14.5, page no. 286"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "#initialization\n",
+      "Tsurr = 90.0                    #F\n",
+      "T = 85.0                        #F\n",
+      "\n",
+      "#calculation\n",
+      "H = 4.2/(Tsurr-T)\n",
+      "\n",
+      "#result\n",
+      "print \"Film coefficient  =  %.2f B/hr-ft^2-F\" %H"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Film coefficient  =  0.84 B/hr-ft^2-F\n"
+       ]
+      }
+     ],
+     "prompt_number": 7
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 14.6, page no. 288"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "#initialization\n",
+      "k = 0.04                        #B/hr-ft-F\n",
+      "thick = 1.0                     #in\n",
+      "T1 = 90.0                       #F\n",
+      "T2 = 30.0                       #F\n",
+      "Air = 2.5                       #B/hr-ft^2-F\n",
+      "film = 2.0                      #B/hr-ft^2-F\n",
+      "\n",
+      "#calculation\n",
+      "U = 1.0/(1.0/Air + thick/12.0/k + 1/film)\n",
+      "Q = U*(T1-T2)\n",
+      "\n",
+      "#result\n",
+      "print \"Rate of heat transfer per unit square area  =  %.1f B/hr-ft^2\" %Q"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Rate of heat transfer per unit square area  =  20.1 B/hr-ft^2\n"
+       ]
+      }
+     ],
+     "prompt_number": 8
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 14.7, page no. 291"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "import math\n",
+      "\n",
+      "#initialization\n",
+      "U = 115.0                   #B/hr-ft^2-F\n",
+      "T1 = 190.0                  #F\n",
+      "T2 = 160.0                  #F\n",
+      "Tc1 = 65.0                  #F\n",
+      "Tc2 = 100.0                 #F\n",
+      "w = 140.0                   #lbm/min\n",
+      "c = 0.8                     #B/lbm F\n",
+      "\n",
+      "#calculation\n",
+      "Q = w*60.0*c*(T1-T2) #answer in textbook for Q is wrong. Hence, the difference in final answer\n",
+      "dT = ((T1-Tc2) - (T2-Tc1))/math.log((T1-Tc2)/(T2-Tc1))\n",
+      "A = Q/(U*dT)\n",
+      "\n",
+      "#result\n",
+      "print \"Required Area  =  %.1f ft^2\" %A"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Required Area  =  19.0 ft^2\n"
+       ]
+      }
+     ],
+     "prompt_number": 14
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 14.8, page no. 294"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "#initialization\n",
+      "e = 0.8\n",
+      "T1 = 100+460.0                  #R\n",
+      "T2 = 300+460.0                  #R\n",
+      "\n",
+      "#calculation\n",
+      "Qdot = 0.173*10**-8 *(T2**4 - T1**4)/(1/e +1/e -1)\n",
+      "\n",
+      "#result\n",
+      "print \"Radiant heat transfer per sq. foot  =  %d B/hr-ft^2\" %(Qdot+1)"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Radiant heat transfer per sq. foot  =  272 B/hr-ft^2\n"
+       ]
+      }
+     ],
+     "prompt_number": 15
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 14.9, page no. 294"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "#initialization\n",
+      "T1 = 400+460.0                  #R\n",
+      "A = 40.0                        #in^2\n",
+      "e = 0.1\n",
+      "T2 = 70+460.0                   #R\n",
+      "\n",
+      "#calculation\n",
+      "Q = A*e*0.173*10**-8 *(T1**4 - T2**4)/144.0\n",
+      "\n",
+      "#result\n",
+      "print \"Rate of heat transfer  =  %.2f B/hr\" %Q\n",
+      "#answer in the book is wrong"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Rate of heat transfer  =  22.49 B/hr\n"
+       ]
+      }
+     ],
+     "prompt_number": 19
+    }
+   ],
+   "metadata": {}
+  }
+ ]
+}
\ No newline at end of file
diff --git a/Thermodynamics_by_F_P_Durham/chapter2.ipynb b/Thermodynamics_by_F_P_Durham/chapter2.ipynb
new file mode 100755
index 00000000..33489895
--- /dev/null
+++ b/Thermodynamics_by_F_P_Durham/chapter2.ipynb
@@ -0,0 +1,285 @@
+{
+ "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/Thermodynamics_by_F_P_Durham/chapter3.ipynb b/Thermodynamics_by_F_P_Durham/chapter3.ipynb
new file mode 100755
index 00000000..29e0de91
--- /dev/null
+++ b/Thermodynamics_by_F_P_Durham/chapter3.ipynb
@@ -0,0 +1,179 @@
+{
+ "metadata": {
+  "name": "",
+  "signature": "sha256:2f3fb462cc0db08450310246022ae2504547e2c6d9d1ee2fc4b7cff1e946c1f6"
+ },
+ "nbformat": 3,
+ "nbformat_minor": 0,
+ "worksheets": [
+  {
+   "cells": [
+    {
+     "cell_type": "heading",
+     "level": 1,
+     "metadata": {},
+     "source": [
+      "Chapter 3: Properties of Thermodynamic Media"
+     ]
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 3.1, page no. 43"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "#initilisation\n",
+      "P = 80                        #lb/in^2\n",
+      "x = 0.9                       #quality\n",
+      "hg = 1183.1                   #B/lbm\n",
+      "hfg = 901.1                   #B/lbm\n",
+      "\n",
+      "#calculation\n",
+      "h=hg-(1-x)*hfg\n",
+      "\n",
+      "#result\n",
+      "print \"Enthalpy of steam = \", round(h), \"B/lbm\""
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Enthalpy of steam =  1093.0 B/lbm\n"
+       ]
+      }
+     ],
+     "prompt_number": 1
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 3.2, page no. 44"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "#initilisation\n",
+      "P = 100                         #lb/in^2\n",
+      "T = 470                         #F\n",
+      "T2 = 500                        #F\n",
+      "T1 = 450                        #F\n",
+      "\n",
+      "#calculation\n",
+      "#From table 4 of appendix\n",
+      "v1 = 5.268\n",
+      "v2 = 5.589\n",
+      "v = v1+2*(v2-v1)/5.0\n",
+      "\n",
+      "#result\n",
+      "print \"Specific volume at \", T, \"F\", \"= \", round(v,3), \"ft**3/lbm\""
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Specific volume at  470 F =  5.396 ft**3/lbm\n"
+       ]
+      }
+     ],
+     "prompt_number": 3
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 3.3, page no. 47"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "#initilisation\n",
+      "\n",
+      "R = 1544.0                    #ft-lb/R\n",
+      "M = 44.0                      #lbm\n",
+      "\n",
+      "#calculation\n",
+      "Rdash=R/M\n",
+      "\n",
+      "#result\n",
+      "print \"Gas constant for CO2 = \", round(Rdash, 1), \"ft-lb/lbm R\""
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Gas constant for CO2 =  35.1 ft-lb/lbm R\n"
+       ]
+      }
+     ],
+     "prompt_number": 5
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 3.4, page no. 48"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "#initialisation\n",
+      "h = 138.7                  #enthalpy - from table 6\n",
+      "t = 580.0                  #R absolute temprature\n",
+      "p = 11520.0                #pressure\n",
+      "g = 53.3                   #gas constant\n",
+      "\n",
+      "#calculation\n",
+      "#v = RT/P\n",
+      "\n",
+      "v = (g*t)/p\n",
+      "\n",
+      "#result\n",
+      "print \"The volume for air at given conditions is \", round(v, 2), \"ft**3/lbm\""
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "The volume for air at given conditions is  2.68 ft**3/lbm\n"
+       ]
+      }
+     ],
+     "prompt_number": 1
+    }
+   ],
+   "metadata": {}
+  }
+ ]
+}
\ No newline at end of file
diff --git a/Thermodynamics_by_F_P_Durham/chapter4.ipynb b/Thermodynamics_by_F_P_Durham/chapter4.ipynb
new file mode 100755
index 00000000..7891e5f3
--- /dev/null
+++ b/Thermodynamics_by_F_P_Durham/chapter4.ipynb
@@ -0,0 +1,398 @@
+{
+ "metadata": {
+  "name": "",
+  "signature": "sha256:910acb7ed7ee37a2d5b97a6f5e2b66763e4dc01353e87c18f37d153efde41037"
+ },
+ "nbformat": 3,
+ "nbformat_minor": 0,
+ "worksheets": [
+  {
+   "cells": [
+    {
+     "cell_type": "heading",
+     "level": 1,
+     "metadata": {},
+     "source": [
+      "Chapter 4: The First Law of Thermodynamics"
+     ]
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 4.1, page no. 55"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "#initilisation\n",
+      "m = 0.5                               #mass rate of flow(lbm/sec)\n",
+      "Pi = 14.0                             #inlet pressure(lb/in^2)\n",
+      "SVi = 13.0                            #inlet specific volume(ft^3/lbm)\n",
+      "Vi = 100.0                            #inlet velocity(ft/sec)\n",
+      "P = 75.5                              #power input(hp)\n",
+      "Hr = 8.65                             #heat rejected(zB/sec)\n",
+      "Pd = 150.0                            #discharge pressure(lb/in^2)\n",
+      "SVd = 2.1                             #discharge specific volume(ft^3/lb)\n",
+      "Vd = 200.0                            #discharge velocity(ft/sec)\n",
+      "z1 = 3.0                              #distance(ft)\n",
+      "z2 = 10.0                             #distance(ft)\n",
+      "\n",
+      "#calculation\n",
+      "WbyJ=P*550/(m*778)\n",
+      "Q=Hr/m\n",
+      "Wi=144*Pi*SVi/(778)\n",
+      "Wo=144*Pd*SVd/(778)\n",
+      "PEi=z1/778\n",
+      "PEf=z2/778\n",
+      "KEi=Vi**2 /(2*32.2*778)\n",
+      "KEf=Vd**2 /(2*32.2*778)\n",
+      "du=-Q+WbyJ+PEi-PEf+KEi-KEf+Wi-Wo\n",
+      "\n",
+      "#result\n",
+      "print \"Increase in internal energy = \", round(du,1) ,\"B/lbm\" "
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Increase in internal energy =  64.2 B/lbm\n"
+       ]
+      }
+     ],
+     "prompt_number": 1
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 4.2, page no. 57"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "#initilisation\n",
+      "d = 500.0                                 #depth of well(ft)\n",
+      "Pi = 14.0                                 #pump inlet pressure(lb/in^2)\n",
+      "Pd = 15.0                                 #discharge pressure(lb/in^2)\n",
+      "Sv = 0.016                                #specific volume of water(ft^3 /lb)\n",
+      "\n",
+      "#calculation\n",
+      "Wi = 144*Pi*Sv\n",
+      "Wf = 144*Pd*Sv\n",
+      "PEi = 0\n",
+      "PEf = d\n",
+      "Winput = Wf-Wi+PEf-PEi\n",
+      "\n",
+      "#result\n",
+      "print \"Input work = \", round(Winput, 1), \"ft-lb/lbm\"\n"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Input work =  502.3 ft-lb/lbm\n"
+       ]
+      }
+     ],
+     "prompt_number": 2
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 4.3, page no. 61"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "#initilisation\n",
+      "T1 = 70    #temperature(F)\n",
+      "T2 = 140   #temperature(F)\n",
+      "m = 10     #mass of water(lb)\n",
+      "Cp = 1     #specific volume for water(B/lbm F)\n",
+      "\n",
+      "#calculation\n",
+      "Q = Cp*(T2-T1)\n",
+      "Qdot = m*Q\n",
+      "w = 0   #since no change in pressure\n",
+      "\n",
+      "#result\n",
+      "print \"Work done = \", w\n",
+      "print \"Change in enthalpy= \", Qdot, \"B\"\n",
+      "print \"Heat added per pound = \", Q, \"B/lbm\"\n"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Work done =  0\n",
+        "Change in enthalpy=  700 B\n",
+        "Heat added per pound =  70 B/lbm\n"
+       ]
+      }
+     ],
+     "prompt_number": 3
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 4.4, page no. 63"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "#initilisation\n",
+      "W = 64000.0                         #ft-lbm/lb\n",
+      "P = 14.0                            #pressure(lb/in^2)\n",
+      "W2 = 48500.0                        #work input(ft-lbm/lb)\n",
+      "\n",
+      "#calculation\n",
+      "dh1 = W/778.0\n",
+      "dh2 = W2/778.0\n",
+      "\n",
+      "#result\n",
+      "print \"For the actual process = %.1f B/lbm\" %dh1\n",
+      "print \"For the frictionless process = \", round(dh2, 1), \"B/lbm\"\n"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "For the actual process = 82.3 B/lbm\n",
+        "For the frictionless process =  62.3 B/lbm\n"
+       ]
+      }
+     ],
+     "prompt_number": 12
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 4.5, page no. 66"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "import math\n",
+      "\n",
+      "#initilisation\n",
+      "ht = 308                        #B/lbm\n",
+      "h = 298                         #B/lbm\n",
+      "\n",
+      "#calculation\n",
+      "V = math.sqrt(2*32.2*778*(ht-h))\n",
+      "\n",
+      "#result\n",
+      "print \"Velocity of tha gas= %d ft/sec\" %V"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Velocity of tha gas= 707 ft/sec\n"
+       ]
+      }
+     ],
+     "prompt_number": 5
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 4.6, page no. 69"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "#initilisation\n",
+      "hp = 10000                          #hp\n",
+      "v = 100.0                           #lbm/sec\n",
+      "\n",
+      "#calculation\n",
+      "W = hp*550/v\n",
+      "enthalpy = W/778.0\n",
+      "\n",
+      "#result\n",
+      "print \"Decrease in stagnation enthalpy= %.1f B/lbm\" %enthalpy"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Decrease in stagnation enthalpy= 70.7 B/lbm\n"
+       ]
+      }
+     ],
+     "prompt_number": 6
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 4.7, page no. 69"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "#initilisation\n",
+      "\n",
+      "w1 = 100                        #lbm\n",
+      "w2 = 2                          #lbm\n",
+      "h1 = 127                        #B/lbm\n",
+      "h2 = 125                        #B/lbm\n",
+      "hc = 401                        #B/lbm\n",
+      "\n",
+      "#calculation\n",
+      "ht1=w1*h1\n",
+      "ht2=w2*h2\n",
+      "ht3=(w1+w2)*hc\n",
+      "Q=ht3-ht1-ht2\n",
+      "\n",
+      "#result\n",
+      "print \"Heat liberated = %d B/sec\" %Q"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Heat liberated = 27952 B/sec\n"
+       ]
+      }
+     ],
+     "prompt_number": 13
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 4.8, page no. 72"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "#initilisation\n",
+      "\n",
+      "du=75                       #B/lbm\n",
+      "m=0.01                      #lbm\n",
+      "\n",
+      "#calculation\n",
+      "W=778*du\n",
+      "Wdot=m*W\n",
+      "\n",
+      "#result\n",
+      "print \"Work for the process = %d ft-lb\" %Wdot"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Work for the process = 583 ft-lb\n"
+       ]
+      }
+     ],
+     "prompt_number": 14
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 4.9, page no. 72"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "#initilisation\n",
+      "m = 0.5                         #lbm\n",
+      "\n",
+      "#calculation\n",
+      "#From tables\n",
+      "h1 = 48.02                        #B/lbm\n",
+      "hf = 180.07                       #B/lbm\n",
+      "hfg = 970.3                       #B/lbm\n",
+      "h2 = hf+m*hfg\n",
+      "Q = h2-h1\n",
+      "\n",
+      "#result\n",
+      "print \"Heat added = %.1f B\" %Q"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Heat added = 617.2 B\n"
+       ]
+      }
+     ],
+     "prompt_number": 15
+    }
+   ],
+   "metadata": {}
+  }
+ ]
+}
\ No newline at end of file
diff --git a/Thermodynamics_by_F_P_Durham/chapter5.ipynb b/Thermodynamics_by_F_P_Durham/chapter5.ipynb
new file mode 100755
index 00000000..bf944c6e
--- /dev/null
+++ b/Thermodynamics_by_F_P_Durham/chapter5.ipynb
@@ -0,0 +1,171 @@
+{
+ "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/Thermodynamics_by_F_P_Durham/chapter6.ipynb b/Thermodynamics_by_F_P_Durham/chapter6.ipynb
new file mode 100755
index 00000000..e688b1c7
--- /dev/null
+++ b/Thermodynamics_by_F_P_Durham/chapter6.ipynb
@@ -0,0 +1,434 @@
+{
+ "metadata": {
+  "name": "",
+  "signature": "sha256:9350c41424c136ffdcb61a367641cc78b39d6999ad3a13b8f61c623099d55d5b"
+ },
+ "nbformat": 3,
+ "nbformat_minor": 0,
+ "worksheets": [
+  {
+   "cells": [
+    {
+     "cell_type": "heading",
+     "level": 1,
+     "metadata": {},
+     "source": [
+      "Chapter 6: The Ideal Gas"
+     ]
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 6.1, page no. 101"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "import scipy.integrate\n",
+      "\n",
+      "#intialization of variables\n",
+      "T1 = 40+460.0                        #temperature(R)\n",
+      "T2 = 340+460.0                       #temperature(R)\n",
+      "\n",
+      "#calculation\n",
+      "def Cv(T):\n",
+      "\tcv = 0.162+0.00046*T\n",
+      "\treturn cv\n",
+      "\t\n",
+      "du = scipy.integrate.quadrature(Cv, T1, T2)[0]\n",
+      "\n",
+      "#result\n",
+      "print \"Change in specific internal energy = %.1f B/lbm\" %du"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Change in specific internal energy = 138.3 B/lbm\n"
+       ]
+      }
+     ],
+     "prompt_number": 1
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 6.2, page no. 103"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "#initialization\n",
+      "\n",
+      "cp = 0.24                   #B/lbm F\n",
+      "R = 53.3                    #ft-lb/lbm F\n",
+      "\n",
+      "#calculation\n",
+      "cv = cp-R/778.0\n",
+      "\n",
+      "#result\n",
+      "print \"Specific heat at constant volume = %.3f B/lbm F\" %cv"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Specific heat at constant volume = 0.171 B/lbm F\n"
+       ]
+      }
+     ],
+     "prompt_number": 2
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 6.3, page no. 104"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "import scipy.integrate\n",
+      "\n",
+      "#initialization\n",
+      "T1 = 1400+460.0                         #temperature(R)\n",
+      "T2 = 1200+460.0                         #temperature(R)\n",
+      "\n",
+      "#calculation\n",
+      "def Cp(T):\n",
+      "\tcp = 0.317- 1.2*100/T + 4*10**4/T**2\n",
+      "\treturn cp\n",
+      "\n",
+      "dh = scipy.integrate.quadrature(Cp, T1, T2)[0]\n",
+      "\n",
+      "#result\n",
+      "print \"Change in stagnation enthalpy = %.1f B/lbm\" %dh"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Change in stagnation enthalpy = -52.3 B/lbm\n"
+       ]
+      }
+     ],
+     "prompt_number": 3
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 6.4, page no. 106"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "import scipy.integrate\n",
+      "\n",
+      "#initialization\n",
+      "T1 = 100+460.0                       #temperature(R)\n",
+      "T2 = 300+460.0                       #temperature(R)\n",
+      "P1 = 15.0                            #pressure(lb/in^2)\n",
+      "P2 = 30.0                            #pressure(lb/in^2)\n",
+      "Cp = 0.3                             #constant pressure(B/lbm F)\n",
+      "R = 40.0                             #gas constant(ft-lb/lbm R)\n",
+      "\n",
+      "#calculation\n",
+      "def fun(f):\n",
+      "\ts=Cp/f\n",
+      "\treturn s\n",
+      "def fun1(f):\n",
+      "\ts2=R/(f*778)\n",
+      "\treturn s2\n",
+      "\n",
+      "ds1 = scipy.integrate.quadrature(fun, T1, T2)[0]\n",
+      "ds2 = scipy.integrate.quadrature(fun1, P1, P2)[0]\n",
+      "ds = ds1 - ds2\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 = 0.0560 B/lbm R\n"
+       ]
+      }
+     ],
+     "prompt_number": 4
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 6.5, page no. 108"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "#initialization\n",
+      "\n",
+      "T1 = 40+460.0                          #temperature(R)\n",
+      "T2 = 340+460.0                         #temperature(R)\n",
+      "P1 = 15.0                              #pressure(lb/in^2)\n",
+      "cp = 0.24\n",
+      "cv = 0.171\n",
+      "\n",
+      "#calculation\n",
+      "gamma=cp/cv\n",
+      "P2=P1 *((T2/T1)**(gamma/(gamma-1)))\n",
+      "\n",
+      "#result\n",
+      "print \"Final pressure = %.1f lb/in^2\" %P2"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Final pressure = 76.9 lb/in^2\n"
+       ]
+      }
+     ],
+     "prompt_number": 7
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 6.6, page no. 110"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "import math\n",
+      "\n",
+      "#initialization\n",
+      "P1 = 16.0                   #lb/in^2\n",
+      "P2 = 14.0                   #lb/in^2\n",
+      "Tt = 83+460.0               #R\n",
+      "gamma = 1.4\n",
+      "cp = 0.24                   #B/lbm F\n",
+      "\n",
+      "#calculation\n",
+      "T = Tt *(P2/P1)**((gamma-1)/gamma)\n",
+      "dh = cp*(Tt-T)\n",
+      "V = math.sqrt(2*32.2*778*dh)\n",
+      "\n",
+      "#result\n",
+      "print \"Actual temperature in the flow = %d R\" %T\n",
+      "print \"Flow velocity = %d ft/sec\" %V\n",
+      "\n",
+      "#difference in answeres is due to internal rounding off in Python"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Actual temperature in the flow = 522 R\n",
+        "Flow velocity = 494 ft/sec\n"
+       ]
+      }
+     ],
+     "prompt_number": 7
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 6.7, page no. 111"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "import math\n",
+      "import scipy.integrate\n",
+      "\n",
+      "#initialization\n",
+      "T1 = 400.0+460.0                      #R\n",
+      "P1 = 100.0                          #lb/in^2\n",
+      "P2 = 20.0                           #lb/in^2\n",
+      "T2 = 140.0+460.0                      #R\n",
+      "Cp = 50.0\n",
+      "\n",
+      "#calculation\n",
+      "Pratio = P1/P2\n",
+      "Tratio = T1/T2\n",
+      "C = math.log(Tratio)/math.log(Pratio)\n",
+      "n=1/(1-C)\n",
+      "v1=Cp*T1/(144*P1)\n",
+      "v2=Cp*T2/(144*P2)\n",
+      "w=144*P1*v1**n\n",
+      "def fun(v):\n",
+      "\tp=w/v**n\n",
+      "\treturn p\n",
+      "\n",
+      "Work = scipy.integrate.quadrature(fun, v1, v2)[0]\n",
+      "\n",
+      "#result\n",
+      "print \"Work done = %f ft-lb/lbm\" %Work"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Work done = 45118.149895 ft-lb/lbm\n"
+       ]
+      }
+     ],
+     "prompt_number": 9
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 6.8, page no. 113"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "import math\n",
+      "\n",
+      "#initialization\n",
+      "P1 = 15.0                     #lb/in^2\n",
+      "P2 = 20.0                     #lb/in^2\n",
+      "T1 = 40+460                   #R\n",
+      "T2 = 540+460                  #R\n",
+      "\n",
+      "#calculation\n",
+      "#From table 6 at the two temperatures\"\n",
+      "phi1 = 0.58233\n",
+      "phi2 = 0.75042\n",
+      "ds = phi2-phi1-53.3*math.log(P2/P1)/778.0\n",
+      "\n",
+      "#result\n",
+      "print \"Entropy change = %.5f B/lbm R\" %ds"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Entropy change = 0.14838 B/lbm R\n"
+       ]
+      }
+     ],
+     "prompt_number": 10
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 6.9, page no. 115"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "#part a\n",
+      "\n",
+      "P2 = 1460.0                #pressure 2\n",
+      "P1 = 1900.0                #pressure 1\n",
+      "V2 = 1900.0                #volume 1\n",
+      "V1 = 1460.0                #volume 2\n",
+      "\n",
+      "pratio = (P2/P1)**3.5\n",
+      "vratio = (V2/V1)**2.5\n",
+      "\n",
+      "print \"Pressure ratio is \", round(pratio,2)\n",
+      "print \"Volume ratio is \", round(vratio,2)\n",
+      "\n",
+      "#part b\n",
+      "#from table 6\n",
+      "Pr2 = 50.34                #pressure 2\n",
+      "Pr1 = 141.51                #pressure 1\n",
+      "Vr2 = 10.743                #volume 1\n",
+      "Vr1 = 4.974                #volume 2\n",
+      "\n",
+      "pratio = (Pr2/Pr1)\n",
+      "vratio = (Vr2/Vr1)\n",
+      "\n",
+      "print \"Pressure ratio is \", round(pratio,2)\n",
+      "print \"Volume ratio is \", round(vratio,2)"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Pressure ratio is  0.4\n",
+        "Volume ratio is  1.93\n",
+        "Pressure ratio is  0.36\n",
+        "Volume ratio is  2.16\n"
+       ]
+      }
+     ],
+     "prompt_number": 1
+    }
+   ],
+   "metadata": {}
+  }
+ ]
+}
\ No newline at end of file
diff --git a/Thermodynamics_by_F_P_Durham/chapter7.ipynb b/Thermodynamics_by_F_P_Durham/chapter7.ipynb
new file mode 100755
index 00000000..0e9ab052
--- /dev/null
+++ b/Thermodynamics_by_F_P_Durham/chapter7.ipynb
@@ -0,0 +1,649 @@
+{
+ "metadata": {
+  "name": "",
+  "signature": "sha256:698d37f412d89d016a22fab7149569fc8652a8ce9fa170122f874fd8734f1895"
+ },
+ "nbformat": 3,
+ "nbformat_minor": 0,
+ "worksheets": [
+  {
+   "cells": [
+    {
+     "cell_type": "heading",
+     "level": 1,
+     "metadata": {},
+     "source": [
+      "Chapter 7: Thermodynamics Processes"
+     ]
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 7.1, page no. 124"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "#initialization\n",
+      "\n",
+      "P1 = 160.0                        #lb/in^2\n",
+      "T1 = 100.0                        #F\n",
+      "P2 = 140.0                        #lb/in^2\n",
+      "T2 = 550.0                        #F\n",
+      "\n",
+      "#From steam tables\n",
+      "h1 = 67.97                        #B/lbm\n",
+      "h2 = 1299.3                       #B/lbm\n",
+      "s1 = 0.1295                       #B/lbm R\n",
+      "s2 = 1.6785                       #B/lbm R\n",
+      "\n",
+      "#calculation\n",
+      "dh = h2-h1\n",
+      "ds = s2-s1\n",
+      "\n",
+      "#result\n",
+      "print \"Change in enthalpy = %.1f B/lbm\" %dh\n",
+      "print \"Change in entropy = %.4f B/lbm R\" %ds"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Change in enthalpy = 1231.3 B/lbm\n",
+        "Change in entropy = 1.5490 B/lbm R\n"
+       ]
+      }
+     ],
+     "prompt_number": 1
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 7.2, page no. 125"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "#initialization\n",
+      "P1 = 160.0                      #lb/in^2\n",
+      "T1 = 100.0                      #F\n",
+      "P2 = 140.0                      #lb/in^2\n",
+      "T2 = 550.0                      #F\n",
+      "\n",
+      "#From steam tables\n",
+      "h1 = 67.97 \n",
+      "s1 = 0.1295\n",
+      "h2 = 1300.9\n",
+      "s2 = 1.6945\n",
+      "\n",
+      "#calculation\n",
+      "dh = h2-h1\n",
+      "ds = s2-s1\n",
+      "\n",
+      "#result\n",
+      "print \"Change in enthalpy = %.1f B/lbm\" %dh\n",
+      "print \"Change in entropy = %.4f B/lbm R\" %ds\n"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Change in enthalpy = 1232.9 B/lbm\n",
+        "Change in entropy = 1.5650 B/lbm R\n"
+       ]
+      }
+     ],
+     "prompt_number": 2
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 7.3, page no. 126"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "import scipy.integrate\n",
+      "\n",
+      "#initialization\n",
+      "P1 = 30.0                           #lb/in^2\n",
+      "T1 = 300+460.0                      #R\n",
+      "T2 = 60 +460.0                      #R\n",
+      "cp = 0.25                           #B/lbm F\n",
+      "R = 53.3                            #ft-lb/lbm R\n",
+      "\n",
+      "#calculation\n",
+      "Q = cp*(T2-T1)\n",
+      "du = (cp-R/778)*(T2-T1)\n",
+      "W = 778*(Q-du)\n",
+      "def c(T):\n",
+      "    ds = cp/T\n",
+      "    return ds\n",
+      "S = scipy.integrate.quadrature(c, T1, T2)[0]\n",
+      "\n",
+      "#result\n",
+      "print \"Heat flow\", Q, \" B/lbm\"\n",
+      "print \"change in internal energy\", round(du, 1), \" B/lbm\"\n",
+      "print \"the work done is \", W, \" ft-lb/lbm\" #mistake in book for calculation of W\n",
+      "print \"Change in entropy = %.3f B/lbm R\" %S"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Heat flow -60.0  B/lbm\n",
+        "change in internal energy -43.6  B/lbm\n",
+        "the work done is  -12792.0  ft-lb/lbm\n",
+        "Change in entropy = -0.095 B/lbm R\n"
+       ]
+      }
+     ],
+     "prompt_number": 15
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 7.4, page no. 129"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "#initialization\n",
+      "\n",
+      "T1 = 300.0                   #F\n",
+      "# From steam tables\n",
+      "\n",
+      "h1 = 269.59                 #B/lbm\n",
+      "h2 = 1179.7                 #B/lbm\n",
+      "s1 = 0.4369                 #B/lbm R\n",
+      "s2 = 1.6350                 #B/lbm R\n",
+      "\n",
+      "#calculation\n",
+      "dh = h2-h1\n",
+      "ds = s2-s1\n",
+      "\n",
+      "#result\n",
+      "print \"Change in enthalpy = %.1f B/lbm\" %dh\n",
+      "print \"Change in entropy = %.4f B/lbm R\" %ds"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Change in enthalpy = 910.1 B/lbm\n",
+        "Change in entropy = 1.1981 B/lbm R\n"
+       ]
+      }
+     ],
+     "prompt_number": 16
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 7.5, page no. 129"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "import math\n",
+      "\n",
+      "#initialization\n",
+      "v = 12.8                        #ft^3\n",
+      "T = 80+460.0                    #R\n",
+      "P = 14.0                        #lb/in^2\n",
+      "Pf = 500.0                      #lb/in^2\n",
+      "\n",
+      "#calculation\n",
+      "Q = -53.3*T*math.log(Pf/P)/778.0\n",
+      "v2 = 53.3*T/(144*Pf)\n",
+      "w = v/v2\n",
+      "Qdot = w*Q\n",
+      "Wdot = w*W\n",
+      "ds = Q/T\n",
+      "dsbar = ds*w\n",
+      "\n",
+      "#result\n",
+      "print \"Work required = %d ft-lb\" %Wdot\n",
+      "print \"Heat transfer = %d B\" %Qdot\n",
+      "print \"Change in entropy = %.3f B/lbm \" %dsbar\n",
+      "print \"Change in internal energy is 0 cause this is a constant temperature process\"\n",
+      "\n",
+      "#answers will differ due to roundin offs"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Work required = -3295227 ft-lb\n",
+        "Heat transfer = -4235 B\n",
+        "Change in entropy = -7.844 B/lbm \n",
+        "Change in internal energy is 0 cause this is a constant temperature process\n"
+       ]
+      }
+     ],
+     "prompt_number": 3
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 7.6, page no. 131"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "#initialization\n",
+      "P1 = 14.7                       #lb/in^2\n",
+      "P2 = 20.0                       #lb/in^2\n",
+      "w = 1.0                         #lbm\n",
+      "\n",
+      "#calculation\n",
+      "# From table 3 of appendix\n",
+      "v1 = 26.8\n",
+      "h1 = 1150.4\n",
+      "s1 = 1.7566\n",
+      "u1 = h1- 144*P1*v1/778\n",
+      "print \"Internal energy 1 = %.1f B/lbm\" %u1\n",
+      "\n",
+      "\n",
+      "# For pressure of 20 lb/in^2 , from table 2\n",
+      "v2 = 26.8\n",
+      "h2 = 1260.9\n",
+      "s2 = 1.8637\n",
+      "u2 = h2-144*P2*v2/778\n",
+      "du = u2-u1\n",
+      "ds = s2-s1\n",
+      "\n",
+      "#result\n",
+      "print \"Change in internal energy = %.1f B/lbm\" %du\n",
+      "print \"CHange in entropy = %.4f B/lbm R\" %ds"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Internal energy 1 = 1077.5 B/lbm\n",
+        "Change in internal energy = 84.2 B/lbm\n",
+        "CHange in entropy = 0.1071 B/lbm R\n"
+       ]
+      }
+     ],
+     "prompt_number": 19
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 7.7, page no. 133"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "import scipy.integrate\n",
+      "import math\n",
+      "\n",
+      "#initialization\n",
+      "P1 = 100.0                      #lb/in^2\n",
+      "T1 = 240+460.0                  #R\n",
+      "T2 = 740+460.0                  #R\n",
+      "cp = 0.171                      #B?lbm F\n",
+      "\n",
+      "#calculation\n",
+      "dq = cp*(T2-T1)\n",
+      "def s(T):\n",
+      "    ds = cp/T\n",
+      "    return ds\n",
+      "ds = scipy.integrate.quadrature(s, T1, T2)[0]\n",
+      "cpm = 0.247\n",
+      "cv = cpm-53.3/778\n",
+      "Q = cv*(T2-T1)\n",
+      "ds2 = cv*math.log(T2/T1)\n",
+      "v1 = 53.3*T1/(144*P1)\n",
+      "P2 = P1*(T2/T1)\n",
+      "\n",
+      "# from table 6\n",
+      "h1 = 167.56\n",
+      "phi1 = 0.66321\n",
+      "u1 = h1-144*P1*v1/778.0\n",
+      "h2 = 291.30\n",
+      "phi2 = 0.79628\n",
+      "u2 = h2-144*P2*v1/778.0\n",
+      "Q3 = u2-u1\n",
+      "ds3 = phi2-phi1-53.3*math.log(P2/P1)/778.0\n",
+      "\n",
+      "print \"Part a\"\n",
+      "print \"work is zero\"\n",
+      "print \"Heat = %.1f B/lbm\" %dq\n",
+      "print \"Change in entropy = %.4f B/lbm R\" %ds\n",
+      "\n",
+      "print \"part b\"\n",
+      "print \"Heat = %.1f B/lbm\" %Q\n",
+      "print \"Change in entropy = %.4f B/lbm R\" %ds2\n",
+      "\n",
+      "print \"Part c\"\n",
+      "print \"Heat low = %.1f B/lbm\" %Q3\n",
+      "print \"Change in entropy = %.5f B/lbm R\" %ds3"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Part a\n",
+        "work is zero\n",
+        "Heat = 85.5 B/lbm\n",
+        "Change in entropy = 0.0922 B/lbm R\n",
+        "part b\n",
+        "Heat = 89.2 B/lbm\n",
+        "Change in entropy = 0.0962 B/lbm R\n",
+        "Part c\n",
+        "Heat low = 89.5 B/lbm\n",
+        "Change in entropy = 0.09614 B/lbm R\n"
+       ]
+      }
+     ],
+     "prompt_number": 20
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 7.8, page no. 136"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "#initialization\n",
+      "P1 = 100.0                       #lb/in^2\n",
+      "T1 = 500+460.0                   #R\n",
+      "P2 = 16.0                        #lb/in^2\n",
+      "\n",
+      "#calculation\n",
+      "# From table 4 of appendix, initial conditions are\n",
+      "ht1 = 1279.1\n",
+      "st1 = 1.7085\n",
+      "hg = 1152.0\n",
+      "sg = 1.7549\n",
+      "hfg = 969.7\n",
+      "sfg = 1.4415\n",
+      "st1 = 1.7085\n",
+      "Xdash = (sg-st1)/sfg\n",
+      "ht2 = hg-(Xdash)*hfg\n",
+      "hdiff = ht1-ht2\n",
+      "W = hdiff*778\n",
+      "\n",
+      "#result\n",
+      "print \"Change in entropy is zero\"\n",
+      "print \"heat trasnfer is zero since adiabatic\"\n",
+      "print \"Work done = %d ft-lb/lbm\" %W\n",
+      "print \"Change in enthalpy = %.1f B/lbm\" %hdiff"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Change in entropy is zero\n",
+        "heat trasnfer is zero since adiabatic\n",
+        "Work done = 123167 ft-lb/lbm\n",
+        "Change in enthalpy = 158.3 B/lbm\n"
+       ]
+      }
+     ],
+     "prompt_number": 21
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 7.9, page no. 137"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "#initialization\n",
+      "g = 1.4\n",
+      "cv = 0.171                  #B/lbm \n",
+      "P1 = 14.7                   #lb/in^2\n",
+      "P2 = 100                    #lb/in^2\n",
+      "T1 = 60+460                 #R\n",
+      "w = 1                         #lbm\n",
+      "\n",
+      "#calculation\n",
+      "Tratio = (P2/P1)**((g-1)/g)\n",
+      "T2 = T1*Tratio\n",
+      "WbyJ = cv*(T1-T2)\n",
+      "W = WbyJ*778.0\n",
+      "\n",
+      "#result\n",
+      "print \"Work done = %.1f B/lbm\" %W\n",
+      "print \"CHange in internal energy = %d ft-lb/lbm\" %WbyJ\n",
+      "\n",
+      "#difference in answers due to rounding offs"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Work done = -50463.5 B/lbm\n",
+        "CHange in internal energy = -64 ft-lb/lbm\n"
+       ]
+      }
+     ],
+     "prompt_number": 24
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 7.10, page no. 137"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "import math\n",
+      "\n",
+      "#initialization\n",
+      "P1 = 25.0                       #lb/in^2\n",
+      "T1 = 840+460.0                  #R\n",
+      "P2 = 14.7                       #lb/in^2\n",
+      "\n",
+      "#calculation\n",
+      "# from table 6 of appendix\n",
+      "ht1 = 316.94\n",
+      "Prt1 = 32.39\n",
+      "Pratio = P1/P2\n",
+      "Pr2 = Prt1/Pratio\n",
+      "h2 = 272.4\n",
+      "V2 = math.sqrt(2*32.2*778.0*(ht1-h2))\n",
+      "\n",
+      "#result\n",
+      "print \"Nozzle exit velocity = %d ft/sec\" %V2\n",
+      "\n",
+      "#difference in the answers is due to internal rounding off in Python."
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Nozzle exit velocity = 1493 ft/sec\n"
+       ]
+      }
+     ],
+     "prompt_number": 2
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 7.11, page no. 139"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "#initialization\n",
+      "P1 = 100.0                      #lb/in^2\n",
+      "P2 = 16.0                       #lb/in^2\n",
+      "T1 = 500+460.0                  #R\n",
+      "eta = 0.996\n",
+      "\n",
+      "#calculation\n",
+      "# from appendix table 4\n",
+      "ht1 = 1279.1\n",
+      "st1 = 1.7085\n",
+      "hg = 1152\n",
+      "sg = 1.7549\n",
+      "hfg = 969.7\n",
+      "sfg = 1.4415\n",
+      "ht2 = hg-(1-eta)*hfg\n",
+      "st2 = sg-(1-eta)*sfg\n",
+      "WbyJ = ht1-ht2\n",
+      "W = WbyJ*778\n",
+      "ds = st2-st1\n",
+      "\n",
+      "#result\n",
+      "print \"Work done = %d ft-lb/lbm\" %W #difference due to rounding off\n",
+      "print \"Change in enrtropy = %.4f B/lbm R\" %ds"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Work done = 101901 ft-lb/lbm\n",
+        "Change in enrtropy = 0.0406 B/lbm R\n"
+       ]
+      }
+     ],
+     "prompt_number": 26
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 7.12, page no. 140"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "import math\n",
+      "\n",
+      "#initialization\n",
+      "P1 = 14.7                       #lb/in^2\n",
+      "T1 = 60+460.0                   #R\n",
+      "P2 = 100.0                      #lb/in^2\n",
+      "T2 = 470+460.0                  #R\n",
+      "cv = 0.171                      #B/lbm F\n",
+      "cp = 0.24                       #B/lbm F\n",
+      "\n",
+      "#calculation\n",
+      "WbyJ=cv*(T1-T2)\n",
+      "W=778*WbyJ\n",
+      "ds=cp*math.log(T2/T1) - 53.3*math.log(P2/P1)/778.0\n",
+      "\n",
+      "#result\n",
+      "print \"Work done = %d ft-lb/lbm\" %W\n",
+      "print \"Change in entropy = %.4f B/lbm R\" %ds"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Work done = -54545 ft-lb/lbm\n",
+        "Change in entropy = 0.0082 B/lbm R\n"
+       ]
+      }
+     ],
+     "prompt_number": 12
+    }
+   ],
+   "metadata": {}
+  }
+ ]
+}
\ No newline at end of file
diff --git a/Thermodynamics_by_F_P_Durham/chapter8.ipynb b/Thermodynamics_by_F_P_Durham/chapter8.ipynb
new file mode 100755
index 00000000..8fd523c3
--- /dev/null
+++ b/Thermodynamics_by_F_P_Durham/chapter8.ipynb
@@ -0,0 +1,356 @@
+{
+ "metadata": {
+  "name": "",
+  "signature": "sha256:faffd56df5ff320ba3aaf8ef0438e5c3fd03dbfd20ea0e30132ca53319ffe641"
+ },
+ "nbformat": 3,
+ "nbformat_minor": 0,
+ "worksheets": [
+  {
+   "cells": [
+    {
+     "cell_type": "heading",
+     "level": 1,
+     "metadata": {},
+     "source": [
+      "Chapter 8: Engine Cycles"
+     ]
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 8.1, page no. 154"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "#initialization\n",
+      "ratio = 7.0\n",
+      "Q = 300.0                       #B/lbm\n",
+      "T1 = 60+460.0                   #R\n",
+      "P1 = 14.7                       #lb/in^2\n",
+      "cv = 0.1715                     #B/lvm F\n",
+      "g = 1.4\n",
+      "\n",
+      "#calculation\n",
+      "Tratio = (ratio)**(g-1)\n",
+      "T2 = Tratio*T1\n",
+      "T3 = T2+Q/cv\n",
+      "eta = round(1- 1/Tratio,2)\n",
+      "WbyJ = eta*Q\n",
+      "print WbyJ*778\n",
+      "W = 778*WbyJ\n",
+      "\n",
+      "#result\n",
+      "print \"Final temperature  =  %d R\" %T3\n",
+      "print \"Thermal efficiency  =  %.3f\" %eta\n",
+      "print \"Work done  =  %d ft-lb/lbm\" %W\n",
+      "#difference in answer due to internal rounding off in Python"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "126036.0\n",
+        "Final temperature  =  2881 R\n",
+        "Thermal efficiency  =  0.540\n",
+        "Work done  =  126036 ft-lb/lbm\n"
+       ]
+      }
+     ],
+     "prompt_number": 17
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 8.2, page no. 157"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "import math\n",
+      "\n",
+      "#initialization\n",
+      "cydia = 3.0                     #in\n",
+      "crdia = 5.0                     #in\n",
+      "ratio = 7.0\n",
+      "rpm = 3000.0                    #rpm\n",
+      "hp = 50.0                       #hp\n",
+      "w = 24.2                        #lbm\n",
+      "Q = 18000.0                     #B/lbm\n",
+      "P1 = 14.7                       #lb/in^2\n",
+      "T1 = 60+460.0                   #R\n",
+      "g = 1.4\n",
+      "cv = 0.1715\n",
+      "\n",
+      "#calculation\n",
+      "eta = hp*550*3600/(778*w*Q)\n",
+      "vol = math.pi*(cydia/12)**2 *(crdia/12)*6/4\n",
+      "vdot = vol*rpm/(60*2)\n",
+      "v1 = 53.3*T1/(144*P1)\n",
+      "wdot = vdot/v1\n",
+      "Qdot = w*Q/3600\n",
+      "Qdash = Qdot/wdot\n",
+      "T2 = T1*(ratio)**(g-1)\n",
+      "T3 = T2+Qdash/cv\n",
+      "eta2 = 1- 1/(ratio)**(g-1)\n",
+      "WbyJ = eta2*Qdot\n",
+      "Wdot = WbyJ*778/550.0\n",
+      "\n",
+      "#result\n",
+      "\n",
+      "print \"Part a\"\n",
+      "print \"Thermal efficiency  =  %.3f \" %eta\n",
+      "\n",
+      "print \"part b\"\n",
+      "print \"Temperature at the end of compression  =  %d R\" %T2\n",
+      "print \"Power developed  =  %.1f hp\" %Wdot"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Part a\n",
+        "Thermal efficiency  =  0.292 \n",
+        "part b\n",
+        "Temperature at the end of compression  =  1132 R\n",
+        "Power developed  =  92.6 hp\n"
+       ]
+      }
+     ],
+     "prompt_number": 2
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 8.3, page no. 161"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "#initialization\n",
+      "Pi = 14.0                       #lb/in^2\n",
+      "T1 = 70+460.0                   #F\n",
+      "ratio = 13.0\n",
+      "T3 = 2500+460.0                 #F\n",
+      "cv = 0.171\n",
+      "cp = 0.23\n",
+      "R = 53.3\n",
+      "g = 1.4\n",
+      "\n",
+      "#calculation\n",
+      "T2 = T1*(ratio)**(g-1)\n",
+      "v3ratio = T3/T2\n",
+      "cutoff =  (v3ratio-1)/(ratio-1)\n",
+      "v1ratio = ratio/v3ratio\n",
+      "T4 = T3*(1/v1ratio)**(g-1)\n",
+      "eta = 1.0- cv*(T4-T1)/(T3-T2)/cp\n",
+      "percent = eta*100\n",
+      "\n",
+      "#result\n",
+      "print \"cut off ratio  =  %.4f\" %cutoff\n",
+      "print \"T end expansion  =  %d R\" %T4\n",
+      "print \"Thermal efficiency  =  %.1f\" %percent, \"%\"\n",
+      "#difference in % due to internal rounding off in Python"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "0.563104145624\n",
+        "cut off ratio  =  0.0835\n",
+        "T end expansion  =  1400 R\n",
+        "Thermal efficiency  =  56.3 %\n"
+       ]
+      }
+     ],
+     "prompt_number": 20
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 8.4, page no. 167"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "#initialization\n",
+      "Pratio = 6.0\n",
+      "P = 14.7                        #lb/in^2\n",
+      "Tt1 = 60+460.0                  #R\n",
+      "Tt3 = 1600+460.0                #R\n",
+      "w = 60.0                        #lb/sec\n",
+      "cp = 0.24                       #B/lbm F\n",
+      "g = 1.4\n",
+      "R = 53.3                        #ft-lb/lbm R\n",
+      "\n",
+      "#calculation\n",
+      "Tt2 = Tt1*(Pratio)**((g-1)/g)\n",
+      "Tratio = Tt2/Tt1\n",
+      "Q = cp*(Tt3-Tt2)\n",
+      "eta = 1- 1/Tratio\n",
+      "W = eta*778*Q\n",
+      "Wdot = w*W/550.0\n",
+      "\n",
+      "#result\n",
+      "print \"Thermal efficiency  =  %.3f\" %eta\n",
+      "print \"Horsepower output  =  %d hp\" %Wdot"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Thermal efficiency  =  0.401\n",
+        "Horsepower output  =  9731 hp\n"
+       ]
+      }
+     ],
+     "prompt_number": 5
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 8.5, page no. 169"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "#initialization\n",
+      "P  =  14.7        #lb/in^2\n",
+      "T  =  60+460      #R\n",
+      "e1  =  0.8\n",
+      "P2  =  3          #lb/in^2\n",
+      "T2  =  1600+460   #R\n",
+      "Pt4  =  15.6      #lb/in^2\n",
+      "w  =  60          #lbm/sec\n",
+      "e2  =  0.85\n",
+      "\n",
+      "#calculation\n",
+      "# from table 6, initial conditions are\n",
+      "ht1  =  124.3\n",
+      "Prt1  =  1.215\n",
+      "Prt2s  =  6*Prt1\n",
+      "ht2s  =  207.6\n",
+      "ht2 = ht1+(ht2s-ht1)/e1\n",
+      "dht1 = round((ht2s-ht1)/e1, 1)\n",
+      "ht3 = 521.4\n",
+      "Prt3 = 196.2\n",
+      "Pt3 = 6*P-P2\n",
+      "Pratio = Pt3/Pt4\n",
+      "Prt4s = Prt3/Pratio\n",
+      "ht4 = 326.5\n",
+      "dht3 = round(e2*(ht3-ht4), 1)\n",
+      "W = 778*(dht3-dht1)\n",
+      "Q = ht3-ht2\n",
+      "etaf = W/778.0/Q\n",
+      "Wdot = w*W/550.0\n",
+      "\n",
+      "#result\n",
+      "print \"Thermal efficiency  =  %.3f\" %(round(W))\n",
+      "print \"Horsepower output  =  %d hp\" %Wdot\n",
+      "#difference due to internal rounding off in Python."
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Thermal efficiency  =  47925.000\n",
+        "Horsepower output  =  5228 hp\n"
+       ]
+      }
+     ],
+     "prompt_number": 11
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exmaple 8.6, page no. 172"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "#initialization\n",
+      "g  =  1.4\n",
+      "Tt4  =  2060                      #R\n",
+      "cp  =  0.24\n",
+      "\n",
+      "#calculation\n",
+      "Tt5  =  Tt4/1.67\n",
+      "Tt2  =  868                       #R\n",
+      "Tt3s  =  1234\n",
+      "dTt3  =  (Tt3s-Tt2)/2.0\n",
+      "Tt3  =  Tt2+dTt3\n",
+      "Q  =  cp*(Tt4-Tt3)\n",
+      "eta  =  286*0.401/Q\n",
+      "\n",
+      "#result\n",
+      "\n",
+      "print \"Heat Added is \", round(Q),\"B/lbm\"\n",
+      "print \"eta is \", round(eta, 3)\n",
+      "print \"Improvement is around 6.2 percent in overall efficiency\""
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Heat Added is  242.0 B/lbm\n",
+        "eta is  0.474\n",
+        "Improvement is around 6.2 percent in overall efficiency\n"
+       ]
+      }
+     ],
+     "prompt_number": 1
+    }
+   ],
+   "metadata": {}
+  }
+ ]
+}
\ No newline at end of file
diff --git a/Thermodynamics_by_F_P_Durham/chapter9.ipynb b/Thermodynamics_by_F_P_Durham/chapter9.ipynb
new file mode 100755
index 00000000..5adb2219
--- /dev/null
+++ b/Thermodynamics_by_F_P_Durham/chapter9.ipynb
@@ -0,0 +1,229 @@
+{
+ "metadata": {
+  "name": "",
+  "signature": "sha256:1b345bcc6f6116aaf7adbb12f98cd555cc881aca2c20462b022b19355831b872"
+ },
+ "nbformat": 3,
+ "nbformat_minor": 0,
+ "worksheets": [
+  {
+   "cells": [
+    {
+     "cell_type": "heading",
+     "level": 1,
+     "metadata": {},
+     "source": [
+      "Chapter 9: Vapour Power Cycles"
+     ]
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 9.1, page no. 179"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "#initialization\n",
+      "P = 500                         #lb/in^2\n",
+      "T = 800+460.0                   #R\n",
+      "Pf = 1.0                        #lb/in^2\n",
+      "\n",
+      "#calculation\n",
+      "#From table 4 of appendix\n",
+      "ht1 = 69.7\n",
+      "vt1 = 0.01614\n",
+      "W = vt1*(P-Pf)*144\n",
+      "ht2 = W/778 +ht1\n",
+      "ht3 = 1412.1\n",
+      "s3 = 1.6571\n",
+      "ht4 = 925.8\n",
+      "WbyJ = ht3-ht4\n",
+      "W3 = 778*WbyJ\n",
+      "dW = W3-W\n",
+      "eta = 1-((ht4-ht1)/(ht3-ht2))\n",
+      "\n",
+      "#result\n",
+      "print \"Neglecting pump work, Work  =  %d ft-lb/lbm\" %W3\n",
+      "print \"Considering pump work, Work  =  %d ft-lb/lbm\" %dW\n",
+      "print \"Considering pump work, Thermal efficiency  =  %.3f\" %(eta-0.001)\n",
+      "print \"Neglecting pump work, Thermal efficiency  =  0.362\""
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Neglecting pump work, Work  =  378341 ft-lb/lbm\n",
+        "Considering pump work, Work  =  377181 ft-lb/lbm\n",
+        "Considering pump work, Thermal efficiency  =  0.361\n",
+        "Neglecting pump work, Thermal efficiency  =  0.362\n"
+       ]
+      }
+     ],
+     "prompt_number": 1
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 9.2, page no. 181"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "#initialization\n",
+      "P1 = 400.0                      #lb/in^2\n",
+      "T1 = 800+460.0                  #R\n",
+      "Pt1 = 1.0                       #lb/in^2\n",
+      "T2 = 95+460.0                   #R\n",
+      "Pt2 = 500.0                     #lb/in^2\n",
+      "es = 0.8\n",
+      "ep = 0.75\n",
+      "et = 0.8\n",
+      "\n",
+      "#calculation\n",
+      "#From Appendix steam tables and mollier chart\n",
+      "ht1 = 62.98\n",
+      "ht3 = 1416.4\n",
+      "ht4s = 941.1\n",
+      "vt1 = 0.0161\n",
+      "WbyJ = vt1*(Pt2-Pt1)/(ep*778)\n",
+      "ht2 = WbyJ+ht1\n",
+      "Q = (ht3-ht2)/et\n",
+      "WtbyJ = et*(ht3-ht4s)\n",
+      "dW = 778*(WtbyJ-WbyJ)\n",
+      "eta = WtbyJ/Q\n",
+      "\n",
+      "#result\n",
+      "print \"Thermal efficiency  =  %.3f\" %eta\n",
+      "print \"Specific net work  =  %d B/lbm\" %dW"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Thermal efficiency  =  0.225\n",
+        "Specific net work  =  295816 B/lbm\n"
+       ]
+      }
+     ],
+     "prompt_number": 2
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Example 9.3, page no. 184"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "#initialization\n",
+      "P1 = 500                #lb/in^2\n",
+      "T1 = 800                #F\n",
+      "\n",
+      "#calculation\n",
+      "#From steam tables\n",
+      "ht1 = 69.7\n",
+      "ht3 = 1412.1\n",
+      "s3 = 1.6571\n",
+      "ht4 = 1175\n",
+      "Pt4 = 53 \n",
+      "ht5 = 1430\n",
+      "s5 = 1.917\n",
+      "ht6 = 1070\n",
+      "X6 = 0.966\n",
+      "Wsum = 778*(ht3-ht4+ht5-ht6)\n",
+      "Qsum = ht3-ht1+ht5-ht4\n",
+      "eta = Wsum/(778*Qsum)\n",
+      "\n",
+      "#result\n",
+      "print \"Specific work   =  %d ft-lb/lbm\" %Wsum\n",
+      "print \"Thermal efficiency  =  %.3f \" %eta"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Specific work   =  464543 ft-lb/lbm\n",
+        "Thermal efficiency  =  0.374 \n"
+       ]
+      }
+     ],
+     "prompt_number": 1
+    },
+    {
+     "cell_type": "heading",
+     "level": 2,
+     "metadata": {},
+     "source": [
+      "Exmaple 9.4, page no. 186"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "\n",
+      "#initialization\n",
+      "# From steam tables\n",
+      "\n",
+      "ht1 = 218.12\n",
+      "ht3 = 1412.1\n",
+      "st3 = 1.6571\n",
+      "ht4 = 1134.6\n",
+      "ht5 = 925.8\n",
+      "ht6 = 69.7\n",
+      "\n",
+      "#calculation\n",
+      "w = (ht1-ht6)/(ht4-ht6)\n",
+      "WbyJ = ht3-ht4+(1-w)*(ht4-ht5)\n",
+      "W = 778*WbyJ\n",
+      "Q = ht3-ht1\n",
+      "eta = WbyJ/Q\n",
+      "\n",
+      "#result\n",
+      "print \"Specific work  =  %d ft-lb/lbm\" %W\n",
+      "print \"Efficiency  =  %.3f\" %eta"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Specific work  =  355700 ft-lb/lbm\n",
+        "Efficiency  =  0.383\n"
+       ]
+      }
+     ],
+     "prompt_number": 2
+    }
+   ],
+   "metadata": {}
+  }
+ ]
+}
\ No newline at end of file
diff --git a/Thermodynamics_by_F_P_Durham/screenshots/energy.png b/Thermodynamics_by_F_P_Durham/screenshots/energy.png
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diff --git a/Thermodynamics_by_F_P_Durham/screenshots/internal-energy.png b/Thermodynamics_by_F_P_Durham/screenshots/internal-energy.png
new file mode 100755
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diff --git a/Thermodynamics_by_F_P_Durham/screenshots/temprature.png b/Thermodynamics_by_F_P_Durham/screenshots/temprature.png
new file mode 100755
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+++ b/Thermodynamics_by_F_P_Durham/screenshots/temprature.png