The work describes the production of investment material on the basis of β cristobalite obtained from β quartz at 1100°C in the presence of mineralizers. The obtained mixture is characterized by beginning of solidification of 9 min and compressive strength of 6.1 mPa; it provides a smooth surface and easy extraction from the mold of chromium nickel alloys.
Reactions in the Na2MoO4–ZrOCl2–ErCl3–H2O system at 20°C were studied by the method of residual concentrations. The insoluble substance formed in this system was investigated by physicochemical methods (XRD, IR spectroscopy, thermal analysis).
To optimize the processes of obtaining high-purity arsine and elemental arsenic by the electrochemical method, the dynamic viscosity is calculated and the kinematic viscosity is measured in solutions of arsenic acid formed by the electrolysis of a solution of hydrolytic sodium arsenite, the main product of the destruction of lewisite, in a temperature range of 20–80°C and a wide concentration range of 20–74 wt %.
Phase equilibria are studied in sections of the systems NaCl–CO(NH2)2–H2O, CaCl2–CO(NH2)2–H2O, and NaCl–CaCl2–CO(NH2)2–H2O at temperatures from 0 to –57°C. The features of the mutual influence of the components on the temperatures of the eutectics in the systems and on the deicing ability of urea–salt mixtures are determined. It is found that the introduction of urea into the systems CaCl2–H2O and NaCl–CaCl2–H2O gives rise to low-temperature eutectics with crystallization temperatures of –54 and –57°C, which are promising for the development of low-temperature deicing agents on their basis.
A short review of the literature data on extraction with hydrophobic bifunctionalized ionic liquids and binary extractants is given to show that these compounds are identical in their compositions and properties. It is noted that the papers on binary extractants were published earlier than the first papers on extraction with bifunctionalized ionic liquids. In contrast to the extraction systems with ionic liquids, extraction processes in the systems with binary extractants are studied in greater detail and grouped into a special class, i.e., binary extraction. It is shown that the main regularities of the distribution of the components in the extraction systems with binary extractants depend on the type of chemical reaction and the character of the interphase distribution.
To predict and evaluate the carbon footprint in the gas phase, furnace fuel oil oxidation in excess air (alpha factor 1.3) was studied over a wide temperature (T = 298–3000 K, P = 0.1 MPa). Equilibrium thermodynamic parameters (entropy, enthalpy, and internal energy) and the concentration distributions of C-, S-, N-, O-, and H-containing components and active particles in the gas phase were determined. Based on the total concentration distribution of C-, S-, N-, O-, and H-containing components and active particles in the gas phase, the weight content of carbon was calculated. Taking into account the chemical matrix of the furnace fuel oil–air system and the weight content of carbon, the man-made load of carbon in the gas phase was found. The results of the work made it possible to evaluate the carbon footprint in the gas phase because of the combustion of fuel, in particular, furnace fuel oil in air. Reduction of the man-made load of carbon oxides (CO, CO2) in the gas phase was achieved by modifying and burning furnace fuel oil in the form of oil-in-water (reverse) emulsions in E-1/9M industrial boilers.
The article discusses the main methods and technologies of three-dimensional printing. The basic principles are presented for technologies that are implemented in powder, polymerization, and extrusion methods of additive manufacturing. The main applications of additive technologies in medicine, pharmacy, and chemical engineering are considered. Based on the review made, conclusions were drawn about the existing problems and limitations that do not allow the integration of additive processes into industry. In addition, the prospects for the development of additive technologies in these applications are considered.
The article presents new details of an algorithm and compares the results of calculating the heat and mass transfer of water and air in spray apparatus for the regimes of cocurrent and countercurrent of phases, taking into account the early crisis of drops drag and the accompanying crisis of heat and mass transfer. The mathematical model used is based on nonstationary differential equations for the flow of a compressible medium, supplemented with the equations of heat and mass transfer from drops to the gas. The known explicit Lax–Wendroff scheme is used in difference analogs of the equations of continuity and phases flow. The distributions of phases velocities and temperatures, and densities of water vapor in air and saturated vapor near the surface of drops in the two-phase flow are calculated to compare the co- and countercurrent flows of phases through the cylindrical apparatus. In particular, the calculations determined the dependences of the average temperatures of the gas and the liquid over the outlet section of the apparatus for each phase on the gas flow through it.
The coagulation ability of organic and inorganic quaternary ammonium salts is assessed comparatively. It is found that the replacement of a hydrogen atom in ammonium chloride with an alkyl radical decreases the consumption of the coagulation agent. The best results are achieved when tetraethylammonium chloride is used as a coagulant. The resulting rubbers and vulcanizates meet the requirements according to their main indicators.
The data on the main (Arsent’evskii, Orongoiskii, Kizirskii, Chineiskii, Patynskii, and Kharlovskii) massifs of stratiform anorthosite deposits in Russia and their location data are given. The problems of classification, petrography, petrochemistry, and mineralogy of these anorthosites are considered.
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：