1. An air-standard Diesel cycle has a compression ratio of 20 and the temperature and pressure at the beginning of the compression stroke are 60F and 14.2 lbf/in', respectively. The mass of air is 0.0015 lbm. The heat addition is 0.9 Btu. Assume variable specific heats (use u, h, s, do not use cp, cv. k) Determine: a) The maximum temperature in "R b) The maximum pressure in lb/in c) The thermal efficiency. d) To investigate the effects of varying compression ratio, plot each of the quantities calculated in parts (a) through (c) for compression ratios ranging from 10 to 30.