Pressurized steam at \(400 \mathrm{~K}\) flows through a long, thinwalled pipe of \(0.6-\mathrm{m}\) diameter. The pipe is enclosed in a concrete casing that is of square cross section and \(1.75 \mathrm{~m}\) on a side. The axis of the pipe is centered in the casing, and the outer surfaces of the casing are maintained at \(300 \mathrm{~K}\). What is the rate of heat loss per unit length of pipe?