Structure Formation in Densely Sintered Household Ceramics

The formation specifics of the structure and phase composition of densely sintered ceramics based on a low-melting argillaceous material from Belarus together with a combined flux and a grog additive are investigated. The correlation between the physicochemical properties, structure, phase composition, and the time-temperature firing schedules of the developed materials are investigated. Electron probe microanalysis makes it possible to monitor variations in the chemical composition at various local sites and compare it with the estimated composition of the mixture. The optimum regimes for the heat treatment of articles are determined. __________ Translated from Steklo i Keramika, No. 6, pp. 32 – 36, June, 2005.     

Prediction of Final Product Properties After Cocurrent Spray Drying

The effect of drying and atomization conditions on the physical properties of powders for agglomerate-like materials and skin-forming material are studied in this article. A neural model is used for powder bulk and tapped density predictions.     

The Effect of Nucleators on the Quality of the Surface of Glass-Ceramic Denture Coatings

The effect of nucleator additives on the surface relief and the degree of crystallization of material intended for the dentine and enamel layers of artificial denture is considered. It is established that hydroxyapatite additive is optimal for producing the required relief in the prime and dentine layers.     

Film Formation in Binary Sol-Gel Systems

The film-forming capacity of binary systems containing Sb₂O₃, SnO₂, CeO₂, Y₂O₃, Nd₂O₃, Bi₂O₃, V₂O₅, ZnO, CuO, CdO, and Al₂O₃ are investigated. The best film-formers are Sb₂O₃ and SnO₂, whereas ZnO, CuO, CdO, and Al₂O₃ cannot produce films of optical quality. The rest of considered oxides do not impair the clarity of coatings when their molding content is 20 – 50%. A proportional dependence is established between the refractive index and the reflection coefficient of a film and the refractive indexes of oxides making parts of this film, as well as between the concentration of deposited FFS, the film-forming capacity of oxides, and the film thickness.     

A New Generation of Steels for Metallic Structures

Metal Science and Heat Treatment -     

Neutron and capture γ-ray accumulation factors in engineering calculations of reactor shielding

Translated from Atomnaya Énergiya, Vol. 66, No. 5, pp. 321–324, May, 1989.     

Analog regulators of the energy-liberation distribution in nuclear reactors

Translated from Atomnaya Énergiya, Vol. 66, No. 2, pp. 81–85, February, 1989.     

Antimutagenic activity of natural phenolic compounds present in the common bean ( Phaseolus vulgaris ) against aflatoxin B 1

Polyphenols with antimutagenic and anticarcinogenic properties are present in fruits, vegetables and legumes. In this study, the Salmonella typhimurium tester strains TA98 and TA100 were used in the microsuspension assay to examine the antimutagenic effect of phenolic compounds extracted from the common bean (Phaseolus vulgaris) against mutagenicity induced by aflatoxin B 1 (AFB 1 ). A dose-response curve was constructed for AFB 1 ; from which a level of 40ng AFB 1 /tube was selected for all antimutagenicity assays. The AFB 1 and phenolic extract (PE) were not toxic to the bacteria at concentrations tested. In the case of PE, results were similar to the number of spontaneous revertants for TA98 and TA100. The inhibitory effect of PE against AFB 1 mutagenicity was dose-dependent at the lower concentrations tested (2.5, 5, 10, 12.5, 15 and 25 μg-equivalent ( + )-catechin/tube for TA98; 0.5, 1, 1.5, 2.5, 5, 10 and 25 μg-equivalent ( + )-catechin/ tube for TA100). Further, a two-stage incubation procedure was used to investigate the potential interaction between PE and AFB 1 . The greatest inhibitory effect of the PE on AFB 1 mutagenicity occurred when PE and AFB 1 were incubated together. When the bacteria were first incubated with PE followed by a second incubation with AFB 1 , lower inhibition was observed. Lower inhibition was also observed when the bacteria were first incubated with AFB 1 followed by a second incubation with PE. The results suggest that the mechanism of inhibition could involve the formation of a chemical complex between of PE and AFB 1 .     

Pulse-Frequency Characteristics in Bifurcation Problems

Generation of self-oscillations under unstable stationary states of nonlinear control systems, which may contain delay of complicated nature (the Andronov–Hopf bifurcation), and approximate design of self-oscillating states and their asymptotes are studied with the help of pulse-frequency characteristics of the linear component of a system.