mean interstitial velocity of the carrier gas

in chromatography
https://doi.org/10.1351/goldbook.M03779
The @I03121@, \(u\) of the @C00863@ multiplied by the @P04821@, \(j\): \[\bar{u} = u\ j\] \[\bar{u} = \frac{F\ j}{\varepsilon_{\text{I}}}\] where \(F\) is the @N04177@, \(\varepsilon_{\text{I}}\) is the @I03120@.
Source:
Orange Book, 2nd ed., p. 103 [Terms]