Added(A)/Deleted(D) following books

 A  Basic_And_Applied_Thermodynamics_by_P._K._Nag/Chapter1.ipynb
A  Basic_And_Applied_Thermodynamics_by_P._K._Nag/Chapter10_qYi9AAs.ipynb
A  Basic_And_Applied_Thermodynamics_by_P._K._Nag/Chapter11_EZtJ7kK.ipynb
A  Basic_And_Applied_Thermodynamics_by_P._K._Nag/Chapter12_KsTKwv5.ipynb
A  Basic_And_Applied_Thermodynamics_by_P._K._Nag/Chapter13_DZJQwFk.ipynb
A  Basic_And_Applied_Thermodynamics_by_P._K._Nag/Chapter14_GYUnehZ.ipynb
A  Basic_And_Applied_Thermodynamics_by_P._K._Nag/Chapter15_teB3fFs.ipynb
A  Basic_And_Applied_Thermodynamics_by_P._K._Nag/Chapter16_fpjEDzx.ipynb
A  Basic_And_Applied_Thermodynamics_by_P._K._Nag/Chapter17_szOwhWr.ipynb
A  Basic_And_Applied_Thermodynamics_by_P._K._Nag/Chapter18_TVmT3rf.ipynb
A  Basic_And_Applied_Thermodynamics_by_P._K._Nag/Chapter19_5sx3l6T.ipynb
A  Basic_And_Applied_Thermodynamics_by_P._K._Nag/Chapter2.ipynb
A  Basic_And_Applied_Thermodynamics_by_P._K._Nag/Chapter20_6AjJCXE.ipynb
A  Basic_And_Applied_Thermodynamics_by_P._K._Nag/Chapter21_iYkzq89.ipynb
A  Basic_And_Applied_Thermodynamics_by_P._K._Nag/Chapter22_OEH4UuY.ipynb
A  Basic_And_Applied_Thermodynamics_by_P._K._Nag/Chapter3.ipynb
A  Basic_And_Applied_Thermodynamics_by_P._K._Nag/Chapter4.ipynb
A  Basic_And_Applied_Thermodynamics_by_P._K._Nag/Chapter5.ipynb
A  Basic_And_Applied_Thermodynamics_by_P._K._Nag/Chapter6_s6H0KKG.ipynb
A  Basic_And_Applied_Thermodynamics_by_P._K._Nag/Chapter7_dQdnyuw.ipynb
A  Basic_And_Applied_Thermodynamics_by_P._K._Nag/Chapter8_oFmkmxA.ipynb
A  Basic_And_Applied_Thermodynamics_by_P._K._Nag/Chapter9_8b0ahS6.ipynb
A  Basic_And_Applied_Thermodynamics_by_P._K._Nag/screenshots/16.11_yr7v4ev.png
A  Basic_And_Applied_Thermodynamics_by_P._K._Nag/screenshots/3.3_3S1AvbP.png
A  Basic_And_Applied_Thermodynamics_by_P._K._Nag/screenshots/7.10_BFuA7JB.png
A  Digital_Communications_by_S._Haykin/README.txt
A  Modern_Digital_And_Analog_Communication_System_by_B._P._Lathi/README.txt
A  sample_notebooks/SPANDANAARROJU/Chapter4_J3M7PEz.ipynb
A  "sample_notebooks/Sadananda CharyArroju/Chapter2.ipynb"

2 files changed, 530 insertions, 0 deletions

diff --git a/sample_notebooks/SPANDANAARROJU/Chapter4_J3M7PEz.ipynb b/sample_notebooks/SPANDANAARROJU/Chapter4_J3M7PEz.ipynb
new file mode 100644
index 00000000..e9783bbb
--- /dev/null
+++ b/sample_notebooks/SPANDANAARROJU/Chapter4_J3M7PEz.ipynb
@@ -0,0 +1,211 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "# 4: Defects in Crystals"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Example number 1, Page number 4.14"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 36,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "equilibrium concentration of vacancy at 300K is 7.577 *10**5\n",
+      "equilibrium concentration of vacancy at 900K is 6.502 *10**19\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "N=6.023*10**26;  #avagadro number\n",
+    "T1=1/float('inf');     #temperature 0K(K)\n",
+    "T2=300;\n",
+    "T3=900;         #temperature(K)\n",
+    "k=1.38*10**-23; #boltzmann constant \n",
+    "deltaHv=120*10**3*10**3/N;    #enthalpy(J/vacancy)\n",
+    "\n",
+    "#Calculation\n",
+    "#n1=N*math.exp(-deltaHv/(k*T1));    #equilibrium concentration of vacancy at 0K\n",
+    "#value of n1 cant be calculated in python, as the denominator is 0 and it shows float division error\n",
+    "n2=N*math.exp(-deltaHv/(k*T2));    #equilibrium concentration of vacancy at 300K \n",
+    "n3=N*math.exp(-deltaHv/(k*T3));    #equilibrium concentration of vacancy at 900K \n",
+    "\n",
+    "#Result\n",
+    "#print \"equilibrium concentration of vacancy at 0K is\",n1\n",
+    "print \"equilibrium concentration of vacancy at 300K is\",round(n2/10**5,3),\"*10**5\"\n",
+    "print \"equilibrium concentration of vacancy at 900K is\",round(n3/10**19,3),\"*10**19\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Example number 2, Page number 4.15"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "fraction of vacancies at 1000 is 8.5 *10**-7\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "nbyN1=1*10**-10;      #fraction of vacancies\n",
+    "T1=500+273;\n",
+    "T2=1000+273;\n",
+    "\n",
+    "#Calculation\n",
+    "lnx=T1*math.log(nbyN1)/T2;\n",
+    "x=math.exp(lnx);      #fraction of vacancies at 1000\n",
+    "\n",
+    "#Result\n",
+    "print \"fraction of vacancies at 1000 is\",round(x*10**7,1),\"*10**-7\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Example number 3, Page number 4.16"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 5,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "concentration of schottky defects is 6.42 *10**11 per m**3\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "d=2.82*10**-10;    #interionic distance(m)\n",
+    "T=300;             #temperature(K)\n",
+    "k=1.38*10**-23;    #boltzmann constant \n",
+    "e=1.6*10**-19;     #charge(coulomb)\n",
+    "n=4;               #number of molecules\n",
+    "deltaHs=1.971*e;   #enthalpy(J)\n",
+    "\n",
+    "#Calculation\n",
+    "V=(2*d)**3;        #volume of unit cell(m**3)\n",
+    "N=n/V;             #number of ion pairs\n",
+    "x=deltaHs/(2*k*T);\n",
+    "n=N*math.exp(-x);    #concentration of schottky defects(per m**3)\n",
+    "\n",
+    "#Result\n",
+    "print \"concentration of schottky defects is\",round(n*10**-11,2),\"*10**11 per m**3\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Example number 4, Page number 4.17"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 16,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "concentration of schottky defects is 9.23 *10**12 per cm**3\n",
+      "amount of climb down by the dislocations is 0.1846 step or 0.3692 *10**-8 cm\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "N=6.026*10**23;    #avagadro number \n",
+    "T=500;             #temperature(K)\n",
+    "k=1.38*10**-23;    #boltzmann constant \n",
+    "deltaHv=1.6*10**-19;     #charge(coulomb)\n",
+    "V=5.55;            #molar volume(cm**3)\n",
+    "nv=5*10**7*10**6;  #number of vacancies\n",
+    "\n",
+    "#Calculation\n",
+    "n=N*math.exp(-deltaHv/(k*T))/V;    #concentration of schottky defects(per m**3)\n",
+    "x=round(n/nv,4);            #amount of climb down by the dislocations(step)\n",
+    "xcm=2*x*10**-8;             #amount of climb down by the dislocations(cm)\n",
+    "\n",
+    "#Result\n",
+    "print \"concentration of schottky defects is\",round(n/10**12,2),\"*10**12 per cm**3\"\n",
+    "print \"amount of climb down by the dislocations is\",x,\"step or\",xcm*10**8,\"*10**-8 cm\" "
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 2",
+   "language": "python",
+   "name": "python2"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 2
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython2",
+   "version": "2.7.11"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 0
+}
diff --git a/sample_notebooks/Sadananda CharyArroju/Chapter2.ipynb b/sample_notebooks/Sadananda CharyArroju/Chapter2.ipynb
new file mode 100644
index 00000000..51d55e0b
--- /dev/null
+++ b/sample_notebooks/Sadananda CharyArroju/Chapter2.ipynb
@@ -0,0 +1,319 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "# 2: Crystallography and Crystal Structures"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Example number 2, Page number 2.21"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 3,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "spacing between (100) plane is 5.64 angstrom\n",
+      "spacing between (110) plane is 3.99 angstrom\n",
+      "answer for spacing between (110) plane given in the book is wrong\n",
+      "spacing between (111) plane is 3.26 angstrom\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "a=5.64;      #lattice constant(angstrom)\n",
+    "h1=1;\n",
+    "k1=0;\n",
+    "l1=0;\n",
+    "h2=1;\n",
+    "k2=1;\n",
+    "l2=0;\n",
+    "h3=1;\n",
+    "k3=1;\n",
+    "l3=1;\n",
+    "\n",
+    "#Calculation\n",
+    "d100=a/math.sqrt(h1**2+k1**2+l1**2);     #spacing between (100) plane\n",
+    "d110=a/math.sqrt(h2**2+k2**2+l2**2);     #spacing between (110) plane\n",
+    "d111=a/math.sqrt(h3**2+k3**2+l3**2);     #spacing between (111) plane\n",
+    "\n",
+    "#Result\n",
+    "print \"spacing between (100) plane is\",d100,\"angstrom\"\n",
+    "print \"spacing between (110) plane is\",round(d110,2),\"angstrom\"\n",
+    "print \"answer for spacing between (110) plane given in the book is wrong\"\n",
+    "print \"spacing between (111) plane is\",round(d111,2),\"angstrom\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Example number 3, Page number 2.22"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 8,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "number of atoms in (100) is 1.535 *10**13 atoms/mm**2\n",
+      "number of atoms in (110) is 1.085 *10**13 atoms/mm**2\n",
+      "number of atoms in (111) is 1.772 *10**13 atoms/mm**2\n",
+      "answers given in the book vary due to rounding off errors\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "a=3.61*10**-7;        #lattice constant(mm)\n",
+    "\n",
+    "#Calculation\n",
+    "A100=a**2;     #surface area(mm**2)\n",
+    "n=1+(4*(1/4));\n",
+    "N1=n/A100;      #number of atoms in (100)(per mm**2)\n",
+    "A110=math.sqrt(2)*a**2;      #surface area(mm**2)\n",
+    "N2=n/A110;      #number of atoms in (110)(per mm**2)\n",
+    "A111=math.sqrt(3)*a**2/2;    #surface area(mm**2)\n",
+    "N3=n/A111;     #number of atoms in (110)(per mm**2)\n",
+    "\n",
+    "#Result\n",
+    "print \"number of atoms in (100) is\",round(N1/10**13,3),\"*10**13 atoms/mm**2\"\n",
+    "print \"number of atoms in (110) is\",round(N2/10**13,3),\"*10**13 atoms/mm**2\"\n",
+    "print \"number of atoms in (111) is\",round(N3/10**13,3),\"*10**13 atoms/mm**2\"\n",
+    "print \"answers given in the book vary due to rounding off errors\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Example number 4, Page number 2.23"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 12,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "wavelength of x rays is 1.552 angstrom\n",
+      "answer varies due to rounding off errors\n",
+      "energy of x rays is 8 *10**3 eV\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "n=4;      \n",
+    "A=107.87;    #atomic weight\n",
+    "rho=10500;     #density(kg/m**3)\n",
+    "N=6.02*10**26;    #number of molecules\n",
+    "theta=19+(12/60);   #angle(degrees)\n",
+    "h=1;\n",
+    "k=1;\n",
+    "l=1;\n",
+    "h0=6.625*10**-34;     #planck constant\n",
+    "c=3*10**8;     #velocity of light(m/s)\n",
+    "e=1.6*10**-19;   #charge(coulomb)\n",
+    "\n",
+    "#Calculation\n",
+    "theta=theta*math.pi/180;     #angle(radian)\n",
+    "a=(n*A/(N*rho))**(1/3);\n",
+    "d=a*10**10/math.sqrt(h**2+k**2+l**2);      \n",
+    "lamda=2*d*math.sin(theta);     #wavelength of x rays(angstrom)\n",
+    "E=h0*c/(lamda*10**-10*e);      #energy of x rays(eV)\n",
+    "\n",
+    "#Result\n",
+    "print \"wavelength of x rays is\",round(lamda,3),\"angstrom\"\n",
+    "print \"answer varies due to rounding off errors\"\n",
+    "print \"energy of x rays is\",int(E/10**3),\"*10**3 eV\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Example number 5, Page number 2.23"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 13,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "density is 2332 kg/m**3\n",
+      "answer varies due to rounding off errors\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "n=8;    #number of atoms\n",
+    "r=2.351*10**-10;     #bond length(angstrom)\n",
+    "A=28.09;                #Atomic wt. of NaCl\n",
+    "N=6.02*10**26           #Avagadro number\n",
+    "\n",
+    "#Calculation\n",
+    "a=4*r/math.sqrt(3);     \n",
+    "rho=n*A/(N*a**3);     #density(kg/m**3)\n",
+    "\n",
+    "#Result\n",
+    "print \"density is\",int(rho),\"kg/m**3\"\n",
+    "print \"answer varies due to rounding off errors\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Example number 6, Page number 2.24"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 14,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "radius of largest sphere is 0.1547 r\n",
+      "maximum radius of sphere is 0.414 r\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "from sympy import Symbol\n",
+    "\n",
+    "#Variable declaration\n",
+    "r=Symbol('r')\n",
+    "\n",
+    "#Calculation\n",
+    "a1=4*r/math.sqrt(3);\n",
+    "R1=(a1/2)-r;           #radius of largest sphere\n",
+    "a2=4*r/math.sqrt(2);\n",
+    "R2=(a2/2)-r;       #maximum radius of sphere\n",
+    "\n",
+    "#Result\n",
+    "print \"radius of largest sphere is\",round(R1/r,4),\"r\"\n",
+    "print \"maximum radius of sphere is\",round(R2/r,3),\"r\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Example number 7, Page number 2.25"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 15,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "percent volume change is 0.5 %\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "r1=1.258*10**-10;     #radius(m)\n",
+    "r2=1.292*10**-10;     #radius(m)\n",
+    "\n",
+    "#Calculation\n",
+    "a_bcc=4*r1/math.sqrt(3);\n",
+    "v=a_bcc**3;\n",
+    "V1=v/2;\n",
+    "a_fcc=2*math.sqrt(2)*r2;\n",
+    "V2=a_fcc**3/4;\n",
+    "V=(V1-V2)*100/V1;           #percent volume change is\",V,\"%\"\n",
+    "\n",
+    "#Result\n",
+    "print \"percent volume change is\",round(V,1),\"%\""
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 2",
+   "language": "python",
+   "name": "python2"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 2
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython2",
+   "version": "2.7.11"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 0
+}