VOL 79, No. 7 (2006)

The results of a study of the features of heat transfer processes in porous thermal insulation at high temperatures are presented. The effect of pore size on the methods of heat transfer in porous materials based on glass is considered, and recommendations are given on methods for calculating heat transfer in materials with closed porosity. Il. 1, bibliography: 3 titles.

Using a numerical model, the influence of the height and location of the overflow threshold on the hydrodynamics of the melt and heat transfer in the melting basin of a glass-making furnace is investigated. The differentiated effect of the overflow threshold on the formation of convection flows and heat and mass transfer in different parts of the brewing basin has been established. It is shown that the studied parameters of the threshold have practically no effect on the intensity of the bulk convection cycle of the melt. At the same time, they significantly affect the hydrodynamics of the melt beyond the threshold. The quantitative relationships between the design parameters of the threshold and individual characteristics of heat and mass transfer in the furnace basin are revealed. Tab. 2, ill. 6, bibliography: 9 titles.

To calculate the compositions of glasses with predicted hydrogen permeability, it is necessary to apply criteria that determine the structure of a substance, such as a silicate modulus, a connectivity factor, and a structure filling factor, as well as a glass comparison factor for a connectivity factor. A graphical method for optimizing the numerical values ??of these criteria has been developed. The compositions of glasses that are promising for the manufacture of hydrogen microballoons are presented. Tab. 2, ill. 1, bibliography: 22 titles.

The possibility of obtaining foam glass-crystalline material from zeolite-containing rocks is considered. It was found that grinding the zeolite-containing raw material to a particle size of less than 0.50 mm and the addition of 13.8% alkali provides the material at a firing temperature of 850 ° C with a bulk density of 340 kg / m ³, strength 1.6 MPa and water absorption 13%. Granular foam zeolite with the addition of alkali is a glass-crystalline material with a higher strength compared to foam glass. Tab. 1, ill. 4, bibliography: 5 titles.

The results of a study of transparent glaze coatings synthesized in the system Na ₂ O - K ₂ O - B ₂ O ₃ - Al ₂ O ₃ - SiO ₂, with a mass content of 12.8% B ₂ O ₃ and 3.9% Al ₂ O ₃. The effect of doubly charged modifier cations SrO, MgO, CaO and their combinations on the physicochemical properties and structure of glasses and coatings based on them has been established. The optimal range of compositions of glaze coatings that meet the requirements of standards for the migration of boron and aluminum into food media has been determined. Il. 2, bibliography: 3 titles.

The ceramic sphero-cones of the Bulgarian settlement (XIV century) have been investigated. Comparison of strength characteristics is carried out. The features of the mineral composition of the samples have been studied. Tab. 1, ill. 2, bibliography: 6 titles.

The structure of PTS polishing cloth with a 30% content of synthetic fibers is described. The results of its testing for the processing of optical materials in pure form and with a specially developed impregnation are presented. The structure and performance of the twisted polishing pad are considered. Tab. 1, bibliography: 8 titles.

Within the framework of an uncoupled quasi-static problem of thermoelasticity, an analytical relationship is obtained, which is a criterion for the thermal strength of nonmetallic materials during pulsed laser annealing. The use of this ratio makes it possible to determine non-destructive modes of laser processing and calculate the required thermal strength of the processed materials, both existing and developed. An experimental verification of the adequacy of the computational model has been carried out. Il. 2, bibliography: 10 titles.