  Correlations in fluids in nonequilibrium steady states are long ranged.
Hence, finite-size effects have important consequences in the nonequilibrium
thermodynamics of fluids. One consequence is that nonequilibrium temperature
fluctuations induce nonequilibrium Casimir-like pressures proportional to the
square of the temperature gradient. Hence, fluctuations cause a breakdown of
the concept of local thermal equilibrium. Furthermore, transport coefficients
become dependent on boundary conditions and on gravity. Thus nonequilibrium
fluctuations affect some traditional concepts in nonequilibrium thermodynamics.
