nIn the process 3 > 4, the gas is placed in thermal contact with a heat reservoirand is compressed isothermally. During this time, the gas expels heat to the reservoir, and work is done on gas.
nIn the final stage, 4
> 1, the gas is compressed adiabatically
the temperature of the gas increases and
work is done on the gas.
nPath quantities( i.e., heat and work) were able to effect a change in state properties.