Just like in the case of the standing-wave system the machine "spontaneously" produces sound if the temperature T is high enough.

The temperature T arises from the fact that the system is in thermal equilibrium with its environment.

Heating the gas up to the initial temperature T increases the entropy by:

The same principle can be applied to a refrigerator working between a low temperature T and ambient temperature.

The reservoir has a constant temperature T, and a chemical potential μ.

At the moment it enters the tube it has the temperature T .

The heat bath remains in thermal equilibrium at temperature T no matter what the system does.

As one varies the temperature T, the probability distribution varies.

Chemical species can have various excitation levels depending on the absolute temperature T, which is a measure of the thermal agitation.

If the temperature T does not vary too much, a linear approximation is typically used: