States of a thermodynamic system can be changed by interacting with its surrounding through work and heat. When this change occurs in a system, it is said that the system is undergoing a process.
A thermodynamic cycle is a sequence of different processes that begins and ends at the same thermodynamic state.
Some sample processes:
- Isothermal process: temperature is constant T=C
- Isobaric process: pressure is constant, P=C
- Isentropic process: entropy is constant, s=C
- Constant-volume process, v=C
- Adiabatic process: no heat transfer, Q=0