Consider a Brayton cycle using air under the following conditions: TA = 298 K, P1 = P4 = 0.1 MPa, P2/P1 = 6, T3 = 973 K, T4 = 563 K. The efficiency of the turbine and compressor are to be 85%. Consider air as an ideal gas stream with CP = 0.79·CP,N2 + 0.21·CP,O2, and assume the molar flows of streams 2 and 4 are equal. Determine the thermal efficiency, heat required, and net work output per mole of air, assuming (a) The heat capacities are temperature-independent at the values at 298 K.