ABSTRACT
Equations (9.27) - (9.29) are, in general exceedingly complicated. Fortunately, they become much simpler in the limit in which U ( R , T ) $ U(R, T) $ https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315196596/a397f31e-8107-49bb-8694-b978d38168d6/content/inline-math10_1.tif"/> varies slowly in space and time. This is exactly the situation in which simple transport processes occur
