A single phase model of mechanisms effecting miscible surfactant oil recovery

The concept of volume averaging is used to theoretically study the mechanisms of mass dispersion, adsorption, and dead-space volume. These mechanisms are important to the understanding of miscible surfactant flooding. After simpiffication based on order-of-magnitude scaling, a linear core model is solved using state variable finite-difference techniques. Mass dispersion and adsorption are shown to be important model parameters while dead-space volume is a rather insensitive model parameter.     

Effects of estrogen-induced hyperlipidemia on the erythrocyte membrane in chicks

The effects of estrogen-induced hyperlipidemia on plasma lipid peroxidation, fatty acid composition and osmotic fragility of erythrocytes in chickens were studied. Young male chickens implanted with estrogen for three wk developed a marked hyperlipidemia. Plasma levels of triglyceride, cholesterol and phospholipid were elevated 68-, four- and 24-fold, respectively, over controls. There was also a two-fold increase in plasma lipid peroxidation measured by the thiobarbituric acid test. Vitamin E supplement (1,000 IU/kg diet) reduced the plasma lipid peroxidation to the control level, but had no effect on the plasma lipid content. Estrogen-induced hyperlipidemia resulted in changes in the fatty acid composition of membrane lipids of erythrocytes. The major changes were an increase in oleic acid from 10.0% to 14.2% and a decrease in linoleic acid from 31.3% to 26.0%. The erytrocytes with an altered membrane fatty acid composition were found to have an increased osmotic fragility. It was apparent that there was a direct correlation between the oleic acid content and the osmotic fragility of erythrocytes.     

Solubilization—A micellar phenomenon

Summary The ability of dilute surfactant solutions to solubilize water-insoluble substances to form stable systems is termed solubilization. Reviewed are the mechanism, methods for measurement, and temperature effect. Discussed in detail are surfactant structure and solubilizates, and the principles of solubilization involved. The application of solubilization to detergency operations is discussed broadly. It is concluded that solubilization is a minor, difficultly measurable factor in the large majority of aqueous cleaning operations.     

Mechanical Behavior of Several Hybrid Ceramic-Matrix-Composite Laminates

Several different hybrid laminated composites comprised of alternating layers of dense ceramic sheets (either SiC or Si₃N₄) and fiber-reinforced ceramic-matrix-composite (CMC) layers (Nicalon fibers with either glass or glass-ceramic matrices) have been fabricated and characterized. The effects of the reinforcement architecture (unidirectional vs cross-ply) and the relative volume fractions of the phases on the tensile and flexural properties have been examined. Comparisons have been made with the properties of the constituent layers. Rudimentary models have been developed to describe the onset of cracking and for the minimum volume fraction of CMC required to develop multiple cracks and thus obtain a high failure strain.     

Solving multicolumn equilibrium stage operations by total linearization

An efficient, reliable and easily programmed method for solving systems of equilibrium stage separation devices is described. The method is an extension of an algorithm developed by Ishii and Otto⁽⁹⁾ for single columns. It solves all equations simultaneously, takes advantage of the basic tridiagonal matrix form form of the linearized steady state equations and can handle configurations which include distillation columns, absorbers and reboiled absorbers. The solution for a thermally coupled distillation system is presented.