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A numerical analysis of the long-range interaction energies between neutral multilamellar lecithin systems has been conducted. The analysis was made in order to verify if the long-range swelling behavior that occurs between the two undulating lipid bilayer are really due to undulation repulsion. The results, which include a long-range van der Waals interaction that continues to be more than 1 order of magnitude greater than the measured undulation repulsion, suggest a different cause for the swelling.

The mechanism of the partial oxidation of methane was studied by combining an isotopic pulse with a gas chromatography-mass spectrum. Large quantities of CHD3, CH2D2 and CH3D, besides CH4 and CD4, were found in the exit gas for a pulse reaction of CH4/CD4/O2 (1/1/1) at 600 deg C over a reduced NiO/SiO2 catalyst. Thus, CH, CH2 and CH3 species are produced during the reaction or that CH4 is activated through its dissociation before its oxidation. The dissociation of methane was found not to be rate determining.

The relation between the degree of aggregation and thermodynamic properties has been investigated. An equation based on the fluctuation theory of Kirkwood and Buff has been derived. The equation related the aggregation of solutes in infinitely dilute aqueous solutions to the slope of the solute activity coefficient and partial molar volume of infinite dilution. The results showed that the aggregation number passes through a maximum with increasing temperature and increases as the pressure increases.

A theoretical model has been developed to analyze the liquid-expanded-liquid-condensed phase transition. The model treats the monolayer as a two-dimensional mixture composed of liquid-condensed domains, disordered molecules in the liquid-expanded state, and free sites. The new equation minimizes the Helmholtz free energy of the monolayer to obtain the equilibrium radius and the equilibrium area fraction of the domains as a function of the average molecular surface area.