VOL 85, No. 2 (2012)

The concept of constructing a mathematical model of a gas-electric glass-melting furnace is formulated. A system of calculated equations for external heat transfer is presented. The boundary conditions of the calculation are considered. Il. 2, bibliography: 3 titles.

Glasses were studied in the Al ₂ O ₃ - P ₂ O ₅ - SiO _{2 suitable for producing green light filters used as traffic signal lights. The following requirements were imposed on glasses: maximum bandwidth at ? max = 500 nm, high temperature resistance and low LTEC - (41-49) * middot; 10 ^-7 K ^-1. The dyes were transition elements, which were introduced into the charge in the form of oxides TiO 2, V 2 O 5, CuO, MoO 3 in the amount of 1% (mass fraction), as well as their pairs in various combinations. EPR and optical spectra were studied. It is shown that the glass composition (mass fraction,%): 55 P 2 O 5; 17,1 Al 2 O 3; 20 SiO 2; 1,5 La 2 O 3; 2 ZrO 2; 2.5 B 2 O 3; 1.5 MoO 3; 0.5 CuO can be recommended for use as heat-resistant green light filters. Il. 7, bibliography: 5 titles.}

Within the framework of the model, which takes into account the different degree of interaction with each other of the structural elements that make up two-component glasses, methods are proposed for calculating the uniform compression modulus for glasses with homogeneous and heterogeneous structures. Lead-silicate and lead-borate glasses are considered as an example of the application of these calculation methods. Tab. 1, ill. 2, bibliography: 5 titles.

The results of studying the creep of polycrystalline ceramics based on metal oxides at temperatures up to 1600 ° C and high loads are presented. These temperatures are in the vicinity of the transition from the brittle behavior of the ceramic to the plastic one. The loads are close to the ultimate strength of materials at a given temperature. It is shown that the elementary deformation mechanism in the entire plasticity range of the samples is the diffusion-viscous (vacancy or interstitial) flow with its varieties - the diffusion displacement of dislocations and crystal boundaries. The data obtained agree with the assumption that the transition from brittle fracture of ceramics to plastic in it requires the appearance of a certain critical concentration of vacancies. These vacancies are formed due to thermal activation and determine the deformation of materials. Tab. 1, ill. 3, bibliography: 7 titles.

The classification of grinding equipment and conditions affecting the process of mechanical processing of raw materials for the production of oxide ceramics is presented. Based on the analysis of grinding (dispersing) processes and mechanochemical activation of alumina, it is recommended to use mills with impact (pressure) - shear loading (drum, vibration, planetary, etc.). Optimal for achieving high values ??of specific surface area and degree of mechanochemical activation are mills with an average energy intensity of 3-10 kW / kg. Tab. 1, ill. 2, bibliography: 25 titles.

Within the framework of a quasi-static uncoupled problem of thermoelasticity, one-sided heating of a glass or ceramic plate freely clamped along the contour by a surface source is considered. An analytical relationship, which is a criterion for the thermal strength of a plate for the case of a linear dependence of Young's modulus and the temperature coefficient of linear expansion of the plate material on temperature, is refined. Il. 1, bibliography: 8 titles.

Yttrium aluminosilicate (YAS) glasses with an yttrium oxide content of up to 23% (molar content) have been obtained, and their properties have been studied. Microspheres with a diameter of 20 - 32 microns have been manufactured for use in brachytherapy. Microspheres are characterized by a completely amorphous structure without the presence of any crystalline inclusions, high shape isometry (particle asphericity less than 5%) and high chemical resistance. Tab. 2, ill. 9, bibliography: 19 titles.

The results of experimental studies of the physicochemical parameters of basalt glasses synthesized by the reduction melting method of dolerite and limestone, differing in the total content of oxides of ferric and ferric iron, are presented. It is shown that with a decrease in the concentration of iron oxides in the melt, its ability to continuously fiberize due to the violation of the glass structure decreases, and the fibers lose strength. Tab. 3, ill. 2, bibliography: 6 titles.