consider the right-circular cylinder of diameter d, length l, and the areas a1, a2, and a 3 representing the base, inner, and top surfaces, respectively. calculate the net radiation heat transfer, in watt, from a1 to a3 if f12 = 0.36 (a fraction of radiation heat transfer from surface 1 to surface 2), A_1 = 0.05 m^2, T_1 = 1000 K, and T_3 = 500 K.