clc; clear; printf("\n Example 9.5\n"); T=295; //initial temperature of surfaces T2f=375; //Final temperature of far surface dT1=900; //Temperature of near face raised DH=4.2e-7; //Thermal diffusivity //The development of the temperature profile is shown in Figure 9.12 //The problem will be solved by taking relatively large intervals for dx. //Choosing dx = 50 mm, the construction shown in Figure 9.12 dx=50e-3; //Because the second face is perfectly insulated, the temperature gradient must // be zero at this point. //It is seen that the temperature is //less than 375 K after time 23dt and greater than 375 K after time 25dt //Thus: //t=24*dt //from equation 9.43 dt=dx^2/(2*DH); t=24*dt; printf("\n The time taken to rise from 295 to 375 K = %.1f h",t/3600);