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{
"metadata": {
"name": ""
},
"nbformat": 3,
"nbformat_minor": 0,
"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"Chapter 21 : Diffusion of Solids"
]
},
{
"cell_type": "heading",
"level": 3,
"metadata": {},
"source": [
"Example 21.1 pageno : 577"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"# Variables\n",
"c_cu = 2.*10**13;\t\t\t#concentration of copper in /m**3\n",
"c_al = 4.*10**6;\t\t\t#concn of copper on other side of Al in /m**3\n",
"\n",
"# Calculations\n",
"t = 3.*10**-3;\t\t \t#thickness in m\n",
"z = (c_cu-c_al)/t;\t\t\t#z = dm/dx,concentration graient\n",
"jx = 10.**21;\t\t \t#outward flux of copperv atoms in /sq m/sec\n",
"d = -jx/z;\t\t\t #diffusivity in sq m/sec\n",
"\n",
"# Results\n",
"print \"Diffusivity (in sq m/sec) = %.2e m**2/s\"%d\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Diffusivity (in sq m/sec) = -1.50e+05 m**2/s\n"
]
}
],
"prompt_number": 1
},
{
"cell_type": "heading",
"level": 3,
"metadata": {},
"source": [
"Example 21.2 pageno : 583"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"import math \n",
"\n",
"c_n = 12.;\t\t\t#nitrogen concentration in kg/m**3\n",
"t = 6.*10**-3;\t\t\t#thickness in m\n",
"\n",
"# Calculations\n",
"z = (c_n-0)/t;\t\t\t#concentration gradient in kg/m**4\n",
"d0 = 5.*10**-7;\t\t\t#in sqm/sec\n",
"q = 75.*10**3;\t\t\t#in j/mol\n",
"r = 8.314;\t\t\t#in J/mol/K\n",
"t = 400.;\t\t\t#in K\n",
"dx = d0*math.exp(-q/(r*t));\t\t\t#diffusivity in sqm/sec\n",
"jx = dx * 2*10**-3;\t\t\t#rate of flow of nitrogen in kg/sqm/sec\n",
"\n",
"# Results\n",
"print \"concentration gradient (in kg/m4) = %.0e\"%z\n",
"print \"Diffusivity (in sqm/sec) = %.3e m**2/s\"%dx\n",
"print \"Rate at which nitrogen escapes (in kg/sqm/sec) = %.3e kg/m**2/s\"%jx\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"concentration gradient (in kg/m4) = 2e+03\n",
"Diffusivity (in sqm/sec) = 8.028e-17 m**2/s\n",
"Rate at which nitrogen escapes (in kg/sqm/sec) = 1.606e-19 kg/m**2/s\n"
]
}
],
"prompt_number": 7
},
{
"cell_type": "heading",
"level": 3,
"metadata": {},
"source": [
"Example 21.4 pageno : 585"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"import math \n",
"\n",
"# variables\n",
"z = 8.;\t\t\t#ratio of diffusion in silicon at 1350 C and 1100 C\n",
"x = math.log(z);\n",
"\n",
"# calculations\n",
"q = x/(1.35*10**-5);\t\t\t#activation energy for silver diffusion in J/mol\n",
"q1 = q/1000.;\t \t\t#in kJ/mol\n",
"\n",
"# results\n",
"print \"Activation Energy in Silver diffusion (in kJ/mol) = %d kJ/mol\"%q1\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Activation Energy in Silver diffusion (in kJ/mol) = 154 kJ/mol\n"
]
}
],
"prompt_number": 10
}
],
"metadata": {}
}
]
}
|
