The paper studies a number of alumina ceramic membrane catalysts of various design and composition for high temperature H₂S decomposition. The design of two types of catalytic membranes used consists of sandwich-like structure including (1) “catalytic layer”/”membrane support”/”membrane layer” and (2) “catalytic layer”/”membrane support”/”intermediate layer”/”membrane layer”. The paper describes: the physical and chemical properties (pore structure, specific surface area and phase composition) of membrane supports and membrane layers calcined at different temperatures; the methods of various composition membrane reactors preparation; the data on membrane permeability on H₂ and H₂S; the test results of prepared membranes in the reaction of H₂S decomposition. The introduction of La₂O₃ modifying additions in a membrane layer is shown to lead to the increase of thermal stability of a membrane. The effective diameter of pores of membrane layer having 5%La₂O₃-γ-Al₂O₃ composition and calcined at 900ºC is three times lower than of the unmodified γ-Al₂O₃. The presence of pure γ-Al₂O₃ phase in the modified membrane layer is observed while the δ-Al₂O₃ phase is formed in the unmodified sample. The pore structure and the thickness of the membrane layer are demonstrated to significantly influence permeability of H₂ and H₂S. There has been observed a significant improvement of the catalytic activity in the H₂S decomposition reaction compared with a granulated catalyst because the separation coefficient of H₂/H₂S is higher than 2.5. It has been determined that the introduction an intermediate layer, which has different effective pore diameter in comparison with the membrane layer, to the membrane composition increases significantly the H₂S conversion. The membrane reactor consisting of the membrane layer (6 m thickness, pore diameter 45 Å) and the intermediate layer (9 m thickness, pore diameter 110 Å) has been found to exhibit maximal efficiency in the H₂S decomposition reaction. The H₂S conversion reaches 65% at 900ºC on the membrane catalyst of optimal composition.

The paper discusses the problem of using the energy of rivers without creating the dams and flooding vast areas and notes that there is a progress in the implementation and development of the ideas of patents in 1925, 1931 (the speed of the workers turbine blades is higher than flow rate). The paper gives the diagrams of the new turbines of this type, for example a balanced 6-tier single-vane turbine, turbine-spiral, a balanced two-bladed turbine. Moreover, the paper deals with the features free-threaded orthogonal turbines in the streams of the limited width and depth. The most important characteristic of a turbine is the turbine's power factor that is equal to the ratio of the energy of the rotating turbine to the kinetic energy of the flow in the current tube passing through the turbine circuit. There is a possibility of a significant increase in the power of the turbine in comparison with the conditions of use unlimited streams. The increase in turbine power in a straitened flow is associated with an increase in the flow velocity in the turbine on the approach to the rear section of the blades’ track. It is set the requirements of the turbine parameters for maximum power at a given water flow and the permissible level rise in the river. These requirements relate to the certain rules for selecting the number of blades (and shading) of the turbine, taking into account the permissible increasing in the water level (backup) in front of the turbine. The paper notes the turbines instability at low speed of rotation, describes a turbine design modification that eliminates this drawback. Modification of the high-speed orthogonal turbines is the use of accelerating blades with a cup-shaped cross-section, placed on the route within a diameter 2 times smaller than the diameter of the main (working) blades of the smoothly streamlined profile. It is concluded that all considered variants of turbines for streams with limited cross-section, the design of the blade system may be made rigid, which eliminates the single central shaft (axle), replacing it with a reference semishafts.

The paper deals with alternative cooling technologies for cryogenic targets with frozen polarization of hydrogen and deuterium nuclei. These targets are used on particle accelerators in experiments on the matter properties, and the results allow improving the fuel cryogenic targets in the implementation of inertial thermonuclear fusion. An important direction here is generation of spherical deuterium-tritium cryogenic targets. The creation of such cryogenic targets and optimization of their design requires large number of scientific experiments on particle accelerators. In accordance with conditions of the physical experiment two types of targets are used: a passive target (only for generation of secondary particles) and an active target (with built-in detector of secondary particles). An example of the active target may be a cryogenic ionization chamber where the extracted beam is used to study the temperature dependence of muonic catalysis of nuclear fusion in deuterium gas, hydrogen-deuterium and mixtures of deuteriumhydrogen. In order to cool cryogenic targets down to temperatures of 4.2–40 K helium refrigerators are used. However, a number of physical experiments especially for particles with large aperture angles require the usage of targets with frozen nuclear polarization. At the same time, the working temperature of the target is reduced to 100–300 mK. These temperatures are reachable in a continuous mode only in dilution refrigerators 3He- 4He. The discovery of the temperature reduction effect in the structures of the normal metal-insulator-superconductor (NIS) by tunneling of electrons through the junction (electron cooling) have led to active study of these devices in labs across the world not only as the active thermometer to measure the temperature in the region of < 300 mK but also as independent generators of cooling power. The main prospect of this direction is the creation of cooling devices on the basis of NIS matrix. In this paper we propose to use these devices with dilution refrigerators or separately in particle accelerators. It will minimize the size of the installation, reduce financial costs and enhance reliability during experiments. An example of a scheme of the accelerator with unit for the target cooling is provided. The paper in accordance with previously published results proposes the method for evaluative calculation of the number of NIS elements for cooler of targets with frozen nuclear polarization of hydrogen and deuterium.

The article analyzes the results of theoretical and experimental studies of the evaporative cryogenic system for extended temperature control channels of high-temperature superconducting cables and hybrid power lines as well as systems for maintaining the thermal regime of cryogenic fuel components in the tanks of aircraft during long space flights. Experimental data obtained with nitrogen and hydrogen are presented. The importance of such studies for practical use in the development of modern cryostat systems is shown. The design of the experimental hybrid power line for studying the processes of thermostating of superconducting cable lines of high power is considered. The main line consists of three sections with different types of thermal insulation and current inputs which provide the supply of an electric current of high power to superconducting veins with a minimum external heat input. Unique experimental data on heat inflows from the outer surface of the main line at various sites have been obtained. The article shows it is possible to fully compensate external heat input into the cryogenic line, and, if necessary, to lower the temperature of the cryogenic coolant in the section with the evaporative cryostat system. With the help of a mathematical model describing the physical processes in the thermostatic channel with the evaporative cryostat system, the estimates were made using liquid nitrogen and liquid hydrogen as the working fluid for various mass flow rates of the coolant supply in order to determine the possible length of the cryostat working zone of the extended superconducting cable. Calculated data are obtained on the change in temperature, pressure, and cooling capacity of an evaporative cryostat system along the length of an extended cryostat.

The paper deals with the conversion method which leads to the formation of mother liquors as by-products. In some cases, they can be used as commodity products after pre-revision. However, optimization of physical and chemical, and the functional properties of the liquid mixes by empirical way can appear long and inefficient process. The paper employs the physical and chemical analysis of homogeneous systems and a method of mathematical planning of experiment that allows optimizing the liquid mixes both on composition, and on some set functional properties. The paper notes the conversion method of production of potassium nitrate from calcium nitrate and potassium chloride is covered by a number of patents, however, it is not realized in industrial scale so far. The reason for this may be a problem of further use of the mother liquors containing calcium and potassium chlorides and nitrates. In the majority of patents, there are no data on the production of calcium chloride from the mother liquor that testifies to a number of the difficulties connected to crystallization of this salt. The mother liquors of potassium nitrate production can be used as an anti-icing reagent, a coolant, the heat-carrier in power systems, a mineral fertilizer and the heavy liquids in a petroleum industry. However, in each specific case, the certain revision of their composition is required in order to achieve the necessary physical and chemical, and functional properties. The paper analyzes the possibility for using the mother solution in the potassium nitrate production as heavy liquids in the oil industry. Moreover, the paper studies the cuts of the systems CaCl₂ – Ca(NO₃)₂ – М – H₂O where М is the mother solution after the crystallization of potassium nitrate. The density and temperature of the solution freezing are identified in the homogeneous areas of the cuts. It is shown a fundamental possibility for improving the operating characteristics of the mother solutions with the introduction of additional amounts of calcium salts.

The work deals with the development of methods for the synthesis of nanosized materials and proposes a novel approach to the synthesis of nano-dispersed LaCrO₃ (crystallite size 350 Å, specific surface area 27 m² /g) with a small content of impurities by one-step combustion without the stage of high-temperature calcinations. The method involves preparation of solid-state glycine-nitrate precursor, its pelletization and subsequent decomposition during self-propagating high-temperature synthesis. Based on the results of elemental analysis and infrared spectroscopy, the main types of the components’ interactions in Cr- and LaCr-containing precursors have been established depending on the method of their preparation. For the first time, the results of the influence of the addition of ammonia water solution to the composition of the precursors have been presented. These results have allowed for an interpretation of their thermal analysis data. The obtained products of the combustion have been analyzed by a series of physicochemical methods: X-ray diffraction, attenuated total reflection infrared spectroscopy, high-resolution transmission electron spectroscopy, thermal analysis, measurements of the specific surface area. It is established that the precursors composition, the conditions and rate of combustion determine the dispersion and purity of the forming oxide phase. Under the conditions of the self-propagating high-temperature synthesis the product forms at a higher temperature which ensures a high yield of a well-crystallized phase of the perovskite as compared with the volume combustion synthesis. It has been demonstrated a negative influence of the addition of an ammonia solution to the Cr-containing precursors on the phase composition of the combustion product which leads to formation of compounds with a higher onset temperature of their thermolysis. The obtained results may be useful in the synthesis of materials for solid-oxide fuel cells, a new generation of photocatalysts and photoelectrodes for the production of hydrogen under visible light, of membranes and of catalysts for a wide range of various processes.

The paper deals with the corrosion resistant electrodes production by the environmentally friendly magnetron sputtering for use in the acid electrochemical systems with solid polymer electrolyte, in particular, fuel cells, electrolyzers, and oxygen pumps. A technique was found for obtaining electrodes with electrochemical stability that was close to the stability of platinum, but with a sharply reduced content, which would reduce the cost of the corresponding installation. As the basis for the electrodes, titanium was chosen. Both smooth titanium foil and porous titanium were used. Applied coatings consisted of palladium, platinum or platinum with carbon. The coatings thickness and microstructure were tested using Rutherford backscattering and electron microscopy. The stability tests were carried out in 1 M sulphuric acid at 25oC and current density of 50 mA/cm² . The application of these coatings is shown to increase sharply the stability of electrodes and current collectors of titanium foils and porous titanium. The coatings obtained at a direct current sputtering and a negative bias voltage on the titanium substrate have the most dense structure and high stability. In the pulsed mode, the stability was worse and decreased with increasing pulse frequency when obtaining a more porous structure. Comparison of the coatings with different compositions shows that stability of the coating with platinum is higher than stability of the coating with palladium and platinum with carbon. The resulting materials are expected to be used in fuel cells and electrochemical oxygen pumps.

The article analyzes the properties and characteristics of the different types of shaft generator installations on ships with a propeller of both regulated and fixed pitch, and on this basis proposes the technical solutions for their modernization. The main attention is paid to the implementation of the engine mode of the shaft generator to ensure emergency operation of the ship. As a shaft generator it is proposed to use a synchronized asynchronous machine with direct and quadrature excitation. The engine mode of the shaft generator is realized by transferring the synchronized asynchronous machine to the mode of an asynchronous motor with a phase rotor, which allows, under appropriate control, to obtain optimum starting characteristics, namely the minimum starting current at the maximum initial starting moment. The properties of a synchronized asynchronous machine with direct and quadrature excitation for efficient damping of oscillations are suggested to be used in the generator mode of the shaft-generator installation. In order to fully take advantage of the direct and quadrature excitation capabilities of this machine, it is proposed to increase the air gap and the magnetomotive force of the rotor winding. At the same time, an increase in the air gap of the machine will positively affect the reliability of the plant. Two technical solutions for the modernization of the shaft-generator plants were noted to be developed. The firstbase machine, which uses an asynchronous machine with a phase rotor, has a standard design. It is a simple and easily implemented solution. However, this solution has limited possibilities for damping the oscillations. The second one is a base machine also made with an increased air gap and an increased value of the magnetomotive force of the rotor. It has the properties of a synchronized asynchronous machine with direct and quadrature excitation in full. Finally, the article draws attention to the possibility of resonance phenomena appearing in the shaft generator installations, which must be prevented in order to avoid dangerous consequences. This task, as shown in the article, can be effectively solved by using a synchronized asynchronous machine with direct and quadrature excitation in the shaft-plant installation.