The preparation of a modern highly porous insulating material based on silicon dioxide is shown. Using factor analysis, the most significant parameters influencing the formation of the porous structure of gels obtained from alkoxides by the sol-gel method were determined.
On the example of ordered packages of bulk media? balls considered a model of their structure? with cells in the form of conditionally cut (quasi-faceted) parallelepipeds, the vertices of which are located in the centers of eight adjacent granule-balls. Power-law and exponential dependences of the coordination number of a granule-sphere on the packing density of the medium are given. and its porosity?. For relatively narrow, typical for backfill environments, ranges? and ? more accurate linear and non-linear dependencies are presented
The possibility of obtaining crystals of lithium molybdate Li 2 MoO 4 from aqueous solutions activated by low-frequency oscillations of a chemically inert body is considered. It was shown that the activation of the solution leads to an increase in the equilibrium solubility of Li 2 MoO 4 in an aqueous solution in the temperature range 25 28 ° C. The effect of the activation of the solution on the faceting shapes of the grown crystals and the morphology of the facet surface has been established. It is shown that the activation of the solution leads to a decrease in the inclusion of water in crystals and an improvement in the surface quality of the growing crystal.
The composition of the elements of a compact fluorescent lamp is described. The functions and requirements for the bulb, phosphor layer, electrodes and other parts of the lamp are given. Improved technologies for the production of elements of a compact fluorescent lamp are proposed, which can significantly improve the quality of manufactured lamps, increase their service life and significantly expand their practical application.
Gas transport reactions are widely used in the chemistry of solids, since the direct interaction of solid phases with each other is difficult. The developed process of enrichment of kyanite concentrate, supporting the rational direction of the gas transport reactions, made it possible to obtain a product with a high content of aluminum oxide (99%) and a low content of silicon, iron and titanium oxides.
Changes in the phase composition and microstructure of an aluminosilicate refractory material destroyed during its operation in a solid biofuel combustion unit have been investigated. Based on the results of studies carried out using modern methods and their analysis in comparison with the literature data on the chemical composition of volatile combustion products of biofuel and their physicochemical properties, the main reasons for the destruction of the material are revealed.
A description of a mathematical model based on Darcy's law for determining the pressure in the inlet part of the die in the manufacture of large-size composite rods obtained by pultrusion based on glass fibers is given. Is the effect of preheating the glass fiber system shown? binder on the distribution and magnitude of pressure inside the inlet section of the die, the maximum possible pultrusion rates are determined at different preheating temperatures
The results of treatment with a microwave field of silicates (bentonite clay and quartz sand), the effect of the field on the structure and technological characteristics of aqueous suspensions of silicates, physical and mechanical characteristics of ceramic material obtained on their basis are considered. The role of additives (hydrosol of aluminum oxide and aluminum-containing galvanic sludge) on the technological characteristics of aqueous suspensions of silicates and the physical and mechanical properties of ceramic material based on them has been investigated.
The possibilities of using concentrated solar energy to create a light-emitting technology for producing art items with glass enamel are considered. Calculations have been carried out to select the optimal modes of the art enameling process on specially prepared wire frames
The paper presents the results of determining the points of zero charge pH0 and isoelectric potentials (& # 950; -potential) in aqueous solutions for some oxides and hydroxides used in the production of ceramics and glass, as well as various composite materials. A mechanism for the formation of the charge of metal oxides and hydroxides depending on the pH of the medium has been proposed. The influence of the pH of the medium on the dispersed characteristics of hydroxides is shown using the example of Ni (II), Cu (II) and Mn (II) hydroxides.
