Answer is:
non-heat transfer process
Explanation:
Adiabatic process or Isentropic process:
A process, in which the work substance neither receives nor gives out heat to its surroundings, during its expansion or compression is called an adiabatic process. This will happen when the working substance remains thermally insulated, so that no heat enters or leaves it during the process. It is thus obvious, that in an adiabatic process no heat leaves or enters the gas, the temperature of the gas changes, as the work is done at the cost of internal energy and the change in internal energy is equal to the work done.
An adiabatic process is one in which
* No heat enters or leaves the gas
* The temperature of the gas changes
* The change in internal energy is equal to the mechanical work done