Liquid potassium flows in a 1-in ID tube at a mean velocity of 8 ft/sec and a mean temperature of 1200°F. The tube is heated at a constant rate per unit length, but the heat flux varies around the periphery of the tube in a sinusoidal manner, with the maximum heat flux twice the minimum heat flux. If the maximum surface temperature is 1500°F, evaluate the axial mean temperature gradient and plot the temperature around the periphery of the tube. (25)