The tube in a heat exchanger has a 2-in. inner diameter and a 3-in. outer diameter. the thermal conductivity of the tube material is 0.52 btu/h∙ft∙℉, while the inner surface heat transfer coefficient is 50 btu/h∙ft2∙℉ and the outer surface heat transfer coefficient is 10 btu/h∙ft2∙℉. determine the overall heat transfer coefficients based on the outer and inner surfaces.

Air inially occupying a volume of 1 m2 at 100 kpa, 27 c undergoes three internally reversible processes in series. process 1-2 compression to 500 kpa during which pv constant process 2-3 adiabatic expanslon to 100 kpa process 3-1: constant-pressure expansion to 100 kpa (a) calculate the change of entropy for each of the three processes. (b) calculate the heat and work involved in each process. (c) is this cycle a power cycle or refrigeration cycle?