Physical Review E
Laws of thermodynamics
Sheehan [Phys. Rev. E 57, 6660 (1998)] recently discussed the possibility of establishing a dynamically maintained, steady-state pressure gradient in a gas filling a cavity. In this Comment it is pointed out that the pressure gradients in such a system, if attainable in the laboratory, could be used to violate the second law of thermodynamics.
Duncan, Todd L., Comment on “Dynamically maintained steady-state pressure gradients” Physical Review E. 61(4)