Air in an ideal Diesel cycle is compressed from 4L to .25L, and then it expands during the constant pressure heat addition process to 0.50L. Under cold air conditions, how much is the thermal efficiency of this cycle? To prevent gaseous ammonia from leaking out, ammonia is transported in its liquid state through a pipe ( k = 25 W/m*k, D i, pipe = 2.5 cm, D o, pipe = 4cm, and L = 10 m). Since liquid ammonia has a normal boiling point of -33.3 C, the pipe needs to be properly insulated to prevent the surrounding heat from causing the ammonia to boil. The pipe is situated in a laboratory, where air at 20 C is blowing across it with a velocity of 7 m/s. The convection heat transfer coefficient of the liquid ammonia is 100 W/m^2*K. Calculate the minimum insulation thickness for the pipe using a material with k = .75 W/m*K to keep the liquid ammonia flowing at an average temperature of -35 C, while maintaining the pipe outer surface temperature at 10 C