Role of Centrifugal Force

FIGURE 7.13 Foam in cylindrical vessel subject to centrifugal field and in state of mechanical equilibrium. 

However, at equilibrium, the foam should be stable so that the capillary pressure in the Plateau border equals the disjoining pressure Hawa(( ) in the adjacent air-liquid-air (AWA) foam films at the top of the foam column (where h is the film thickness and where we neglect any net curvature of the film). As described in Section 1.3.3, 

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The last group of papers are relative to the computer-simulation study of the rotation-vibration correlations in pure liquids. The main authors are Levesque, Weis and Oxtoby (31,32) who examined liquid and HCl in much detail. A molecular dynamics simulation was carried out using 500 molecules for N2 and 256 for HCl periodic boundary conditions were imposed It was found that, in the isotropic Raman spectrum of liquid N2>intermolecular rotation-vibration interactions are mainly due to short range repulsion and dispersion forces the role of centrifugal forces seems secondary which is an unexpected result. The presence of important interference effects makes any partition illusory. Only intermolecular rotation-vibration correlation effects were examined in the case of infrared and anisotropic Raman spectra of liquid HCl. It results from this calculation that the simple product correlation function is indistinguishable from the total correlation function within the uncertainty of the simulation. This conclusion is similar to that reached by Tarjus and Bratos (12). It should not be forgotten, however, that the latter theory applies to diluted solutions whereas the function determined by Levesque, Weis and Oxtoby is an approximate correlation function of a pure liquid. 

The last method used to prepare GI preforms employs centrifugal force. This method is divided into two categories based on the role of centrifugal force in forming the GI profiles. 

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