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 },
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  {
   "cells": [
    {
     "cell_type": "heading",
     "level": 1,
     "metadata": {},
     "source": [
      "Chapter 2: Acoustics of Buildings"
     ]
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "Example 2.1, Page 52"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "from math import log10\n",
      "\n",
      "#Variable Declaration\n",
      "#delta_L=L2-L1\n",
      "\n",
      "#Calculation\n",
      "#I proportional to square of amplitude so when amplitude is doubled intensity will becomes 4 times \n",
      "#L1=10*l0g10(I1/I0)\n",
      "#L2=10*log10(I2/I0)\n",
      "#delta_L=L2-L1\n",
      "#delta_L=10*log(I1/I0)-10*log(I2/I0)=10*log(I2/I1)\n",
      "I21=4;#I2/I1=4 because intensity=amp^2\n",
      "delta_L=10*log10(I21);#increase in intensity level\n",
      "\n",
      "#Result\n",
      "print 'Increase in intensity level =',round(delta_L,2),'dB'\n"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "Increase in intensity level = 6.02 dB\n"
       ]
      }
     ],
     "prompt_number": 1
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "Example 2.2, Page 52"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "from math import sqrt\n",
      "\n",
      "#Variable Declaration\n",
      "#L2-L1=10*log10(I2/I1)\n",
      "#so , we can write that \n",
      "L2=40  #i dB\n",
      "L1=10 #in dB \n",
      "#where L1 and L2 are intensity level of two waves of same frequency\n",
      "\n",
      "#Calculation\n",
      "L=L2-L1;\n",
      "#let I2/I1=I\n",
      "I=10**(L/10);\n",
      "#let a2/a1=a\n",
      "a=sqrt(I);#Ratio of their amplitudes \n",
      "\n",
      "#Result\n",
      "print 'Ratio of their amplitudes =',round(a,3)"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "Ratio of their amplitudes = 31.623\n"
       ]
      }
     ],
     "prompt_number": 4
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "Example 2.3, Page 53"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "from math import log10\n",
      "\n",
      "#Variable Declaration\n",
      "I1=25.2 #in Wm^-2\n",
      "I2=0.90 #in Wm^-2\n",
      "\n",
      "#Calculation\n",
      "B=10*log10(I1/I2) #Relative loudness of sound in dB\n",
      "\n",
      "#Result\n",
      "print 'Relative loudness of sound = ',round(B,2),'dB'\n"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "Relative loudness of sound =  14.47 dB\n"
       ]
      }
     ],
     "prompt_number": 5
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "Example 2.4, Page 53"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "from math import log10\n",
      "\n",
      "#Variable Declaration\n",
      "I=1e4 #in W/(m*m)\n",
      "I0=1e-12 #in W/(m*m)\n",
      "\n",
      "#Calculation\n",
      "B=10*log10(I/I0);#intensity level\n",
      "\n",
      "#Result\n",
      "print \"intensity level = \",B,'dB'\n"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "intensity level =  160.0 dB\n"
       ]
      }
     ],
     "prompt_number": 6
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "Example 2.5, Page 54"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "#Variable Declaration\n",
      "B=5 # in dB\n",
      "\n",
      "#Calculation\n",
      "#B=10*log(I2/I1)\n",
      "#let I2/I1=x\n",
      "#10*log(x)=5\n",
      "x=10**(5./10);\n",
      "\n",
      "#Result\n",
      "print 'Amplified sound is',round(x,3),'times more intense than the unamplified sound'\n"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "Amplified sound is 3.162 times more intense than the unamplified sound\n"
       ]
      }
     ],
     "prompt_number": 7
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "Example 2.6, Page 57"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "#Variable Declaration\n",
      "d=198; #in meter\n",
      "t=1.2;#in second\n",
      "\n",
      "#Calculation\n",
      "#velocity=distance/time\n",
      "v=2*d/t;#velocity\n",
      "\n",
      "#Result\n",
      "print 'velocity =',v,'m/s'\n"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "velocity = 330.0 m/s\n"
       ]
      }
     ],
     "prompt_number": 16
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "Example 2.7, Page 64"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "#Variable Declaration\n",
      "V=5600  #in  m^3\n",
      "T=2     #in second\n",
      "s=700   #in m^2\n",
      "\n",
      "#Calculation\n",
      "a=0.16*V/(s*T)\n",
      "\n",
      "#Result\n",
      "print \"absorption coefficient =\",a\n"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "absorption coefficient = 0.64\n"
       ]
      }
     ],
     "prompt_number": 8
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "Example 2.8, Page 65"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "#Variable Declaration\n",
      "absorp1=92.90; #in m^^2\n",
      "absorp2=92.90;#in m^2\n",
      "V=2265.6;#in m^3\n",
      "\n",
      "#Calculations\n",
      "T1=0.16*V/(absorp1);\n",
      "T2=0.16*V/(absorp1+absorp2);\n",
      "ans=T2/T1;#effect on Reverberation time\n",
      "\n",
      "#Result\n",
      "print \"Reverberation time reduced to \",ans,\"of original value\"\n"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "Reverberation time reduced to  0.5 of original value\n"
       ]
      }
     ],
     "prompt_number": 10
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "Example 2.9, Page 65"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "#Variable Declaration\n",
      "v=25.2*20.3*8.04 ;#in m^3\n",
      "T=0.75; #in second\n",
      "\n",
      "#Calculations\n",
      "absorp1=500*0.3176 ;#in m^2\n",
      "absorp2=(0.16*v)/T;\n",
      "T1=(0.16*v)/(absorp1+absorp2);#reverbaration time\n",
      "\n",
      "#Result\n",
      "print \"reverbaration time =\",round(T1,3),'sec'\n"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "reverbaration time = 0.635 sec\n"
       ]
      }
     ],
     "prompt_number": 11
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "Example 2.10, Page 66"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "#Variable Declaration\n",
      "v=45*100*17.78;#in m^3\n",
      "\n",
      "#Calculations\n",
      "absorp1=(700*0.03)+(600*0.06)+(400*0.025)+(600*0.3);\n",
      "absorp_p=600*4.3;\n",
      "T1=(0.16*v)/(absorp1);#Reverbaration time (empty hall) \n",
      "T2=(0.16*v)/(absorp_p+absorp1);#Reverbaration time with full capacity\n",
      "\n",
      "#Results\n",
      "print 'Reverbaration time (empty hall) =',round(T1,2),'sec' #printing mistake at the end in the textbook\n",
      "print 'Reverbaration time with full capacity =',round(T2,2),'sec'"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "Reverbaration time (empty hall) = 51.83 sec\n",
        "Reverbaration time with full capacity = 4.53 sec\n"
       ]
      }
     ],
     "prompt_number": 12
    }
   ],
   "metadata": {}
  }
 ]
}