Some considerations on molecular machines and Loschmidt paradox

Molecular machines don’t apparently satisfy the second law of thermodynamics. This holds to the Loschmidt paradox. Boltzmann introduced the irreversible evolution of any system towards a state of mechanical and thermal equilibrium. He expressed this result in his H-theorem. Loschmidt objected that the Boltzmann's result was inconsistent because it was obtained by using a time-symmetric dynamics, in contrast with the time asymmetry of the result. In this paper we show how these two problems can be related to the Gouy-Stodola theorem and to the interactions between open systems or open subsystems in the case of closed or isolated systems.