An overhead 25-m-long, uninsulated industrial steam pipe of 100-mm diameter is routed through a building whose walls and air are at 25°c. pressurized steam maintains a pipe surface temperature of 150°c, and the coefficient associated with natural convection is h = 10 w/m2 ⋅ k. the surface emissivity is ε = 0.8. (a) what is the rate of heat loss from the steam line? (b) if the steam is generated in a gas-fired boiler operating at an efficiency of ηf = 0.90 and natural gas is priced at cg = $0.02 per mj, what is the annual cost of heat loss from the line?