Effects of spatial variations in extended irreversible thermodynamics

A generalization of extended irreversible thermodynamics is obtained by including the gradients of conserved and nonconserved variables in the space of thermodynamical states. The relaxation equations for these additional state variables are derived systematically from the basic postulates of the theory, for the special case of a rigid heat conductor. Finally, the physical implications of our method are discussed and compared with those of other work on the subject.