Reduced phenomenological mobility

From Eqns (6.58) to (6.63), the reduced phenomenological mobilities are obtained as... 

In 1961, Fried (1) demonstrated that aqueous surfactant-stabilized foam could drastically reduce the mobility of gases in porous media. At that time, foam was studied mainly from a phenomenological perspective. In the intervening 30 years, foam has been recognized as a fluid with unique rheological properties within porous media, and the scope of research has expanded to include local pore-scale phenomena and local microstructure. Because of its dispersed nature, foam profoundly affects the flow patterns of nonwetting fluids within porous media. 

Sion under these conditions because the mobility of certain intermediatesized molecules was almost zero. This latter effect increases the absolute separation between the bands because the latter spread over the whole gel, but makes it very difficult to analyze the results as the bands are not in order of molecular size. Since the size of the molecule showing zero-mobility was a function of the pulse duration, these authors used a ramp where the pulse durations increased steadily during the experiment in this way, each molecule was the slowest at one point during the experiment and the effect of band-inversion was somewhat reduced. However, this phenomenological method for obtaining a monotonic mobility-size relationship has been criticized as it is not clear how one can choose a ramp that will work for all distributions of DMA molecules.55... 

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