Concept of critical thickness

The first extensive1 study of x-ray excitation (1.17) as a method of producing x-ray spectra for analytical purposes was carried out by Glocker and Schreiber,17 who not only treated absorption effects very thoroughly and introduced the concept of critical thickness, but who... 

Rupture of foams. In [242], the concept of critical thickness is suggested as a criterion of the rupture of foams. This means that polyhedral foam will rupture as soon as the thickness of some films making the faces of the foam polyhedron cells attains a critical value. Adopting the channel model of the foam, i.e., assuming that the liquid completely resides in Plateau borders, and using Eqs. (7.1.21) and (7.1.23), one can represent the volume fraction of the liquid phase, V (the reciprocal of the foam multiplicity K) in the form... 

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