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diff --git a/1309/CH11/EX11.3/ch11_3.sce b/1309/CH11/EX11.3/ch11_3.sce
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+clc;
+clear;
+printf("\t\t\tChapter11_example3\n\n\n");
+// (a) Calculation of the emissivity of the hole.(b) the rate of radiant emission from the hole
+D=2.5/12; // diameter in ft
+L=4.5/12; // length in ft
+A=(2*%pi*D^2/4)+(%pi*D*L);
+printf("\nThe inside surface area is %.3f sq.ft ",A);
+A_hole=%pi*(1/(8*12))^2/4;
+printf("\nThe area of a 1/8 inch hole is %.3e sq.ft",A_hole);
+f=A_hole/A; // fraction of area removed
+printf("\nThe fraction of area removed is %.3e ",f);
+printf("\n\n\t\t\tSolution to Part (a)\n");
+// for rolled and polished aluminum, that emissivity = 0.039 from appendix table E1
+emissivity=0.039;
+emissivity_hole=emissivity/(emissivity+(1-emissivity)*f);
+printf("\nThe emissivity of the hole is %.4f",emissivity_hole);
+printf("\n\n\t\t\tSolution to Part (b)\n");
+sigma=0.1714e-8; // stefan Boltzmann constant in BTU/(hr~ft^2 degree R)
+T=150+460; // temperature in degree R
+qe=emissivity_hole*sigma*T^4;
+printf("\nThe heat lost per unit area of the hole is %d BTU/hr",qe);
+Qe=A_hole*qe;
+printf("\nThe heat lost by the hole is %.2e BTU/hr",Qe);