Brownian Ratchet in a Thermal Bath Driven by Coulomb Friction
A Brownian Ratchet is a small engine which is conceived to extract work from molecular fluctuations. Examples of Brownian Ratchets occur in the cell, see for instance this nice movie about kinesin.
As well explained by Richard Feynmann, a Brownian Ratchet cannot perform its own task in an equilibrium environment, i.e. the fluctuations feeding energy to the ratchet cannot originate from a single thermal bath, in accordance with the second principle of thermodynamics.… Read the rest