title: Comment on "Dynamically maintained steady-state pressure gradients"
abstract: 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.
authors.affiliation: Center for Science Education, Portland State University, P.O. Box 751, Portland, Oregon 97207, USA.
authors.initials: TL
authors.lastname: Duncan