Kinetic investigations in heterogeneous reaction systems by wavefront analysis

In this paper the previously introduced wavefront analysis is extended to heterogeneous reaction systems, which consist of several reaction steps. It is shown how three mainly informations obtained at the wavefront, namely the damping of the wavefront, the time-gradients at the wavefront and the propagation velocity of the wavefront, can be used for kinetic investigations of a reaction step under consideration.     

Ertragsleistung sowie Gehalte und Zusammensetzung der Fette und Proteine einiger Senfarten und -sorten auf ökologisch stark differenzierten Standorten

Yield as well as Contents and Composition of Fats and Proteins in Several Varieties and Types of Mustard at Distinctly Different Ecological Locations In a cultivation experiment extending over two years the yield of different varieties of Brassica juncea, Brassica nigra and Sinapis alba was examined. Fat content and protein content were determined and the correlations with different characteristics were calculated. Fatty acid composition of the oil showed that erucic acid content was distinctly influenced by the location and the year of cultivation. In all samples, whose erucic acid content showed large difference from average values for the variety, electrophoretic patterns of the proteins were found to be distinctly different, both with respect to number and distribution of the bands.     

Ion exchange kinetics of the protonation of weak acid ion exchange resins

A mathematical model to describe the protonation of weak acid ion-exchange resins with various acids has been developed. The charge profiles calculated using the theory are demonstrated by photographs. Interdiffusion coefficients in the resin phase have been determined and it is shown how they depend on the system parameters and on the properties of the resin.     

Über den Effekt der Einarbeitung von Diolen in Alkydharze auf Basis verzweigter Carbonsäuren

The Effect of the Use of Dihydric Alcohols in the Alkyd Resins Based on Branched Chain Fatty Acids By the modification of alkyd resins, based on the branched chain fatty acids with dihydric alcohols, the properties of the resins are strongly influenced. Not only the length but also the structure of the chain between two hydroxyl groups of the dihydroxy alcohol exert a considerable influence on the mechanical properties of the lacquer film. In addition, the structure of this chain is also important for the chemical resistance. The influence of the dihydroxy alcohol on the mechanical properties of the hardened lacquer films is partly due to the greater flexibility of the cross-linked system and partly due to the better plasticizing effect of the unbound alkyd part.     

The Systems BaO-SrO-TiO2, BaO-CaO-TiO2, and SrO-CaO-TiO2

The solid phases formed at 1400°C. in air in the three-component systems BaO-SrO-TiO₂, BaO-CaO-TiO₂, and SrO-CaO-TiO₂ are described. Besides solid solutions of components with known structures, some new ternary compounds have been studied. The dielectric constants and loss factors of a number of specimens are given. Crystallographic data of the compounds BaCaTiO₄, Ba₃Ca₂Ti₂O₉, and Ca₃Ti₂O₇ and of the solid solution series (Ba, Sr), TiO₄ are presented. The preparation of the new compounds is described in detail.     

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.     

Selective hydrogenation of soybean oil: IV. Fatty acid isomers formed with copper catalysts

Two samples of soybean oil hydrogenated with copper-containing catalysts at 170 and 200 C were analyzed for their natural and isomeric fatty acids. Methyl esters of the hydrogenated oils were separated into saturates, monoenes, dienes and trienes by countercurrent distribution between acetonitrile and pentane-hexane. Monoenes were further separated intocis- andtrans-isomers on a silver-saturated resin column. Double bond location in these fractions was determined by a microozonolysis-pyrolysis technique. The diene fraction was separated with an argentation countercurrent distribution method, and linoleate was identified by infrared, ozonolysis and alkaliisomerization data. The double bonds in thecis-monoenes were located in the 9-position almost exclusively. However, the double bonds in thetrans-monoene were quite scattered with 10- and 11-isomers predominating. About 86% to 92% of the dienes consisted of linoleate as measured by alkali isomerization. Other isomers identified as minor components includecis,trans andtrans, trans conjugated dienes and dienes whose double bonds are separated by more than one methylene group. No. Utiliz. Res. Dev. Div., ARS, USDA.     

Substrate-mediated interactions and intermolecular forces between molecules adsorbed on surfaces

Adsorbate interactions and reactions on metal surfaces have been investigated using scanning tunneling microscopy. The manners in which adsorbates perturb the surface electronic structure in their vicinity are discussed. The effects these perturbations have on other molecules are shown to be important in overlayer growth. Interactions of molecules with surface steps are addressed, and each molecule's electron affinity is shown to dictate its adsorption sites at step edges. Standing waves emanating from steps are demonstrated to effect transient molecular adsorption up to 40 A away from the step edge. Halobenzene derivatives are used to demonstrate how the surface is important in aligning reactive intermediates.