A stainless steel (AISI 304) tube used to transport a chilled pharmaceutical has an inner diameter of 36 mm and a wall thickness of 2 mm. the pharmaceutical and ambient air are at temperatures of 6degree C and 23 degree C, respectively, while the corresponding inner and outer convection coefficients are 400 W/m^2 middot K and 6 W/m^2 middot K, respectively. a. What is the heat gain per unit tube length? b. What is the heat gain per unit length if a 10-mm-thick layer of calcium silicate insulation (k_ins = 0.050 W/m middot K) is applied to the tube?