9.41 A long, uninsulated steam line with a diameter of 100 mm and a surface emissivity of 0.8 transports steam at 150°C and is exposed to atmospheric air and large surroundings at an equivalent temperature of 20°C. a. Calculate the rate of heat loss per unit length for a calm day. b. Calculate the rate of heat loss on a breezy day when the wind speed is 8 m/s. C. . For the conditions of part (a), calculate the rate of heat loss with a 20-mm-thick layer of insulation (k = 0.08 W/m K).