Alloy structures and phase equilibrium diagram of the Hf-Ru-Ir system III. Solidus surface and 1350°C isothermal section of the state diagram in the Hf-HfRu-HfIr region

Translated from Poroshkovaya Metallurgiya, No. 3, pp. 61–67, March, 1992.     

Study of the Polymorphism of Saturated Monoacid Triglycerides II: Polymorphic Behaviour of a 50/50 Mixture of Tripalmitin and Tristearin

The polymorphic behaviour of a 50/50 blend of tripalmitin and tristearin has been investigated in detail using differential scanning calorimetry and X-ray diffraction. The blend is characterized by a greater tendency to β'-crystallization as compared to the pure triglycerides. Tripalmitin and tristearin, when mixed in a 1:1 ratio, are miscible in both the α-form and the β-form. In the β-form, however, demixing occurs, resulting in a 2-phase solid state. The characteristics of the α-form are considerably affected by the crystallization conditions, due to the formation of concentration gradients during crystallization. The β'-form can be obtained from the melt as well as via recrystallization of the α-form, and is characterized by a much higher stability as compared to the pure triglycerides. The X-ray diffraction data of the β'-form of the blend reveal a β₁-crystal structure. The β'-form of the pure triglycerides, however, is characterized by a β'₂-crystal structure. On the basis of the present data, however, no clear structural distinction can be made between β'₂ and β'₁.     

Toxikologie freier Radikale und Antioxidantien unter besonderer Berücksichtigung von Vitamin E

Toxicology of Free Radicals and Antioxidants with Specific Regards to Vitamin E By metabolic activation radicals of xenobiotics can occur in the body which may be toxic by reacting with oxygen. The oxygen radicals formed then react with cellular macromolecules. When reacting with lipids lipid peroxidation occurs. Antioxidants may either inhibit the formation of oxygen radicals or prevent lipid peroxidation. As examples carbon tetrachloride, adriamycin, paraquat and some carcinogens are dealt with. With some toxicity as well as lipid peroxidation are inhibited by vitamin E and other antioxidants. Furthermore, the toxicology of the antioxidants is discussed, because they are themselves transformed into free radicals. Whereas vitamin E has practically no toxic effects, some synthetic antioxidants show carcinogenic effects in animal experiments.     

Thermal/structural dynamic analysis via approximate analytical approach

The present paper uses a classical Galerkin weighted residual formulation to obtain the approximate analytical solution of a thermally loaded beam executing free flexural vibrations. The approach used is one where the time variable is considered in the same manner as the spatial variable, and is included in the basis functions. The basis functions used in the approach are polynomials obtained from the terms of a power series, with the condition of nullity on the boundary. This choice simplifies the algebraic manipulations considerably and yields close form expressions for components of the system matrix. The latter also simplifies the numerical computation of coefficients of the approximating polynomial. The approach provides benefits in terms of increased accuracy and lower computational costs.