At the beginning of the compression process of an air-standard dual cycle with a compression ratio of 18, the temperature is 300 Kelvin and the pressure is 0.1MPa. The pressure ratio for the constant-volume part of the heating process is 1.5:1. The volume ratio for the constant pressure part of the heating process is 1.2:1. Determine:
a.) The thermal efficiency of the cycle.
b.) The mean effective pressure, in MPa.