Question: A stainless steel spherical tank, with an inner diameter of 3 m and a wall thickness of 10 mm, is used for containing a solution undergoing an exothermic reaction that generates 450 W/m3 of heat. The tank is located in a surrounding with air at 15°C. To prevent thermal burns on the skin of people working near the vicinity of the tank, the outer surface temperature should be at 45°C or lower. Determine whether the outer surface of the tank should be polished (ε = 0.2) or painted in black (ε = 0.88). Evaluate the air properties at 30°C and 1 atm pressure. Is this a good assumption?