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The choice of an appropriate method for rare earth element (REE) preconcentration from industrial by-products is a very difficult task. Most of the REE separation reviews focus on liquid extraction methods, whereas sorption processes are usually mentioned in connection with chromatographic individual REE separation. Limited information is currently available on ion exchange methods for REE preconcentration. The REE sorption methods are gradually acquiring great practical significance due to depleting REE sources. The present review deals with the history, recent studies and commercial applications of REE sorption from various complex industrial by-products such as products of apatite treatment, phosphogypsum and uranium ores. It covers an extensive study on the recent research related to use of polymeric ion-exchange sorption materials for REE preconcentration and recovery from various industrial wastes.

The elemental composition of the fragment of one of the biggest meteorites, which entered the Earth's atmosphere over Chelyabinsk, Russia was investigated by instrumental neutron activation analysis at the IBR-2 reactor. A total of 27 major and trace elements Si, Ti, Cr, Al, Fe, Mn, Mg, Ca, Na, K, V, Sc, Co, Ni, Zn, As, Se, Rb, Mo, Ag, Sb, Cs, Sm, Tm, Ir, Au, U was determined in the analyzed fragment. Obtained values were compared with the average composition of LL-chondrites and results reported by other scientific groups.

Activation of a nickel-chromium catalyst for low temperature steam reforming of C2+-alkanes to methane rich gas has been studied by TPR and XRD in situ techniques. The activation procedure has been studied with the following reducing agents: hydrogen, syngas, methanol and the reaction mixture of low-temperature steam reforming. Attempts were made to activate the catalyst at 300, 340 and 420 °C. Activated samples were tested in low-temperature steam reforming of a methane-propane mixture. A passivation process has been proposed and tested for compatibility with following activation in the LTSR reaction mixture.

A series of 11 compounds, including alkali (Li, Na, K, Rb, Cs) and alkaline-earth (Mg, Ca, Sr, Ba) coordination polymers, transition-metal (Cu, Cd) complexes, and the ammonium salt of 3,5-dimethylp...

The component composition of plasma jets generated by a dielectric barrier discharge in helium and air at atmospheric pressure was studied by emission and absorption spectroscopy. The concentration of the main bactericidal component of the air plasma jet (ozone) was determined using both IR and UV absorption spectroscopy to increase the reliability of the measurements. A study of the effects of the plasma jets on Staphylococcus aureus bacteria established that the air jet had a better inactivating effect than the helium jet.

The problem of assessing steels durability, their resistance to brittle fracture in the structures used in various branches of industry, remains relevant at the development of the new equipment and control of the old equipment. Standard strength calculations do not give a complete picture of the ability of steels due to their physical and mechanical properties to resist the formation and further development of defects and cracks under the action of actual stresses. The correct choice of a structural material for technical devices operating at low temperatures, knowledge of its characteristics of resistance to brittle fracture, understanding of brittle fracture mechanism at low temperatures and research in this area are of great importance. Since 1980s, JSC IrkutskNIIkhimmash systematically conducts the research works related to impact strength characteristics. These works are carried out in connection with the need for assessing the resistance to brittle fracture of metal of the equipment for storing oil products, vessels and pipelines, drill pipes and tubing, etc. As a result of many years of research, the authors accumulated significant experimental material in the form of temperature dependences of impact strength - both for the material of various types of blanks (sheets, pipes, forgings) in the state of delivery, and for the metal of technical devices elements after their operation of various duration. The main objective of the article is to assist specialists in establishing the correct choice of steel for the new or old structures in terms of their resistance to brittle fracture without conducting special studies. Specialists can select the closest steel analogue (on chemical composition, mechanical properties, and the type of product without making cuts from the structure or blanks for additional research), and set the numerical value of the impact strength, critical temperature of brittleness and the stress intensity factor for any temperature in the range from –40 to 20° С in order to use them in further calculations.

The effect of γ'- and β-phase particles on the γ–α' thermoelastic martensitic transformation (MT) during heating/cooling and under stress in [001]-oriented single crystals of a Fe – 28% Ni – 17% Co – 11.5% Al – 2.5% Ti (at.%) alloy is studied in tension and compression. The influence of the ageing mode on the Ms temperature is shown. During a simultaneous precipitation of γ'- and β-phase particles following two-step ageing for 4+4 h at 873 K, a 100 K increase in the Ms temperature is observed compared to one-step ageing for 8 h. No differences (asymmetry) in the stresses σcr for the start of the stress-induced γ–α' MT nor in the values of α = dσcr/dT in tension and compression are observed in the crystals with γ'- and γ'+β-phase particles. The absence of asymmetry of σcr and α = dσcr/dT is due to close values of the shape memory effect (SME) and superelasticity (SE) in tension and compression. Upon precipitation of β-phase particles the values of SME and SE decrease.

The article discusses the influence of technological parameters of sulfur electrodes and the concentration composition of the salt-solvation electrolytes TEGDME–LiTFSI on the specific characteristics of Li-S cells obtained under galvanostatic cycling conditions. The dependences of the specific capacity on the composition of the cathode, the charge-discharge current density, as well as capacity retention upon storage are discussed.

The electrochemical properties of LiMn2O4 surface modified with LiNi0.5Mn1.5O4 at different current densities are presented. The electrode with a maximum percentage of covering (14% of LiNi0.5Mn1.5O4) can endure higher current loads compared with the sample consisting 7% of surface layer. The capacity values for these samples at 45° and 30°C are 22 and 31 mAh∙g-1, respectively. This means that the proposed approach can be an effective tool for obtaining electrode materials for high-rate applications.

Experimental and analytical investigations into the synthesis of the ceramic material based on the Ti–Al system with a nanodimensional porous structure are performed. The results of previous studies of the collective of authors show that it is reasonable to produce porous ceramic materials intended to filtrate liquids and gases in the thermal explosion mode (over the entire sample bulk) rather than by the layer-by-layer combustion. Nanoporous ceramic membranes are fabricated by self-propagating high-temperature synthesis (SHS) in one stage with the formation of the TiAl3 compound from a mixture of powders, wt %: 40Ti + 60Al. It is established that the synthesized material consists of the main TiAl3 phase with an insignificant amount of aluminum oxidized into Al2O3 and unreacted. Microstructural analysis of the sample fracture shows that the material has the developed surface and high open porosity. Its empirically determined magnitude reaches 48%, while the pore size ranges from 0.1 to 0.2 μm. The efficiency of fabricated porous material for the Ti–Al-based ceramic SHS filter reaches 99.999%, gas flow resistance is 100 mmHg, and filtration index is 0.062. The gas ultrafiltration capacity reaches 40 L(cm2 h) at a pressure drop across the filter of 2 kPa, while that of water ranges from 2 to 10 L/(cm2 h) at a pressure drop across the filter of 0.1 MPa. Membranes thus fabricated from ceramic materials with the gradient nanoporous structure can be used as filter elements for small installations providing fine water purification with the removal of bacteria, viruses, and dissolved organic carbon and for the fine purification of air and process gases with the removal of dispersed microimpurities and radioactive aerosols. The developed membrane SHS filters can be also demanded for installations operating in aggressive media and/or at high temperatures (up to 1000°C).

The luminescence intensity profiles of Lyman–Birge–Hopfield bands of molecular nitrogen have been calculated for the precipitation into the Earth’s atmosphere of electrons with energies of 10 keV to 10 MeV. With an increase in the energy of electrons penetrating the atmosphere, there is an increase in the contribution of the quenching of the a1Πg N2 state in molecular collisions. This leads to a reduced ratio of the integral luminescence intensities of the Lyman–Birge–Hopfield ultraviolet bands and the second positive system upon an energy increase in high-energy electrons precipitating into the atmosphere.

A porous catalytically active membrane based on α-Al2O3 was synthesized. Powdered additives of the eutectic composition of magnesium oxide and silicon carbide were added to the initial corundum filler to synthesize a membrane framework with high open porosity and physical and mechanical characteristics that was pressed at 40 – 70 MPa followed by sintering in process combustion mode. Additives of Re2O7 andWO2 were added up to 4 mass% to the initial mixture by a simple technological method to impart catalytic properties to the synthesized membrane. Scientific foundations were developed for creating a technology for one-stage production of catalytically active ultraporous membrane converters effective for dehydrogenation of cumene to α-methylstyrene.

The research is devoted to the development of scientific bases for creating a technology for manufacturing heat-resistant membranes based on a highly porous ceramic material with nanoscale pores (nanoporous), which allows increasing the efficiency of high-temperature purification of liquids from submicron dispersed contaminants by tangential filtration. Membranes based on a mixture of Ti and Al powders (40% by 60% mass ratio) were synthesized in one stage using the SHS method in the thermal explosion mode and used as filter elements in the ultrafiltration unit. Using X-ray and SEM methods, it was found that the synthesized material consists of the main phases TiAl3 and Al2O3. Analysis of the microstructure showed that the resulting ceramic material has a multilevel highly developed web-like nanostructure that forms an open porosity of the membrane, which provides the possibility of ultrafiltration.

A porous, catalytically active membrane based on coarse-fraction silicon carbide was synthesized. Ultrafine additives with an eutectic composition of magnesium oxide and silicon carbide, which during sintering at temperatures from 1100 to 1450°C form a liquid phase in the form of clinoenstatite MgSiO3 that wets the coarse-size SiC particles and forms a strong porous framework of the membrane, were introduced into the initial SiC powder to synthesize the membranes. The pore size of the ceramic material was studied as a function of the pressing pressure, which made it possible to obtain a highly porous ceramic membrane with pore size optimized for dehydrogenation of ethylbenzene into styrene. Modification of the pore surfaces to 10% Re – W by means of active components using the alkoxy method is performed in order to give the synthesized membrane the catalytic properties required for realizing the dehydrogenation process.

In antiferromagnetic (AFM) nanoparticles, an additional ferromagnetic phase forms and leads to the appearance in AFM nanoparticles of a noncompensated magnetic moment and the magnetic properties typical of common FM nanoparticles. In this work, to reveal the regularities and differences of the dynamic magnetization switching in FM and AFM nanoparticles, the typical representatives of such materials are studied: CoFe2O4 and NiO nanoparticles with average sizes 6 and 8 nm, respectively. The high fields of the irreversible behavior of the magnetizations of these samples determine the necessity of using strong pulsed fields (amplitude to 130 kOe) to eliminate the effect of the partial hysteresis loop when studying the dynamic magnetic hysteresis. For both types of the samples, coercive force HC at the dynamic magnetization switching is markedly higher than HC at quasi-static conditions. HC increases as the pulse duration τP decreases and the maximum applied field H0 increases. The dependence of HC on field variation rate dH/dt = H0/2τP is a unambiguous function for CoFe2O4 nanoparticles, and it is precisely such a behavior is expected from a system of single-domain FM nanoparticles. At the same time, for AFM NiO nanoparticles, the coercive force is no longer an unambiguous function of dH/dt, and the value of applied field H0 influences more substantially. Such a difference in the behaviors of FM and AFM nanoparticles is caused by the interaction of the FM subsystem and the AFM “core” inside AFM nanoparticles. This circumstance should be taken into account when developing the theory of dynamic hysteresis of the AFM nanoparticles and also to take into account their practical application.

A thermodynamic analysis is performed of the patterns of steam conversion of natural gas at temperatures of 300–600°C, pressures of 0.1–4 MPa and H2O : C molar ratios of 0.8‒1.2. Under these conditions, the reaction product is methane–hydrogen mixtures with hydrogen concentrations of 10–30 vol %. A rise in temperature, molar ratio Н2О : С, and a decrease in pressure contribute to an increase in the concentration of hydrogen in the reaction products. The thermodynamic boundaries of the process with no carbonization of the catalyst are determined. Experiments are performed to obtain methane–hydrogen mixtures from methane with an output concentration of 15–35 vol % hydrogen on industrial Ni-CrOx-Al2O3 catalyst at 325–425°C, a H2O : C molar ratio of 0.8–1.0, and atmospheric pressure. It is shown that under these conditions, the process proceeds without the formation of carbon on the catalyst.

The effect of γ′-phase dispersed particles on the temperature dependence of the stresses of the start of martensitic transformations σcr(T), the shape memory effect, and the superelasticity is investigated depending on aging conditions in the [001]-oriented crystals of the non-equiatomic Fe – 28% Ni – 17% Co – 1.5% Al – 2.5% Ti (at.%) high-entropy alloy under tension/compression. It is shown that σcr(T) during the γ–α′ stressinduced martensitic transformations is independent of the strain method (tension/compression) for small γ′- phase particles with sizes d ≤ 4–6 nm. The value of the reversible strain at tension is 3.5–4.5%, and it is 1.5% at compression. Reasons for strong dependences of the reversible strain and the mechanical hysteresis on the strain method (tension/compression) and particle sizes are discussed.

Understanding the electronic structure of organic/molecular semiconductors and the energetics at their interfaces with metals is critical for organic-based electronics applications. Here we demonst...

The purpose of the work is the application of a non-profiled electrode-brush for mating surfaces machining including that in crossed channels. To achieve the goal set there were problems under solution: the development of essential equipment, electrode-tools, the selection of working environment, the optimization of combined machining modes. To solve the problems set there are used basis regulations of the theory: electric and combined methods of machining, the mathematical apparatus of probability theories and mathematical statistics. In the paper the developed and manufactured plants and electrode-tools are shown. The recommended machining conditions, working environment are shown. The equipment is presented with a small-size plant for high-speed machining with an electrode-brush and a portable plant fixed on a drill rod that with the use of operating fluid recommended allows reducing considerably the terms and cost of metal cutting equipment updating for machining with electric field imposition. In the paper there are considered standard parts: nozzles, ejector bodies, parts of piping hydro-systems. The results of machining parts with crossed channels are shown. The application of processing by an electrode-brush with high circumferential velocities with regard to the work-piece from 35 m/sec and higher allows manufacturing products with the set values. The application of an electrode-brush is efficient for mating surfaces combined machining.

The magnetic structure of the e-Fe2O3 iron oxide polymorphic modification is collinear ferrimagnetic in the range from room temperature to ~150 K. As the temperature decreases, e-Fe2O3 undergoes a magnetic transition accompanied by a significant decrease in the coercivity Hc and, in the low-temperature range, the compound has a complex incommensurate magnetic structure. We experimentally investigated the dynamic magnetization switching of the e-Fe2O3 nanoparticles with an average size of 8 nm in the temperature range of 80–300 K, which covers different types of the magnetic structure of this iron oxide. A bulk material consisting of xerogel SiO2 with the e-Fe2O3 nanoparticles embedded in its pores was examined. The magnetic hysteresis loops under dynamic magnetization switching were measured using pulsed magnetic fields Hmax of up to 130 kOe by discharging a capacitor bank through a solenoid. The coercivity Нс upon the dynamic magnetization switching noticeably exceeds the Нс value under the quasi-static conditions. This is caused by the superparamagnetic relaxation of magnetic moments of particles upon the pulsed magnetization switching. In the range from room temperature to ~ 150 K, the external field variation rate dH/dt is the main parameter that determines the behavior of the coercivity under the dynamic magnetization switching. It is the behavior that is expected for a system of single-domain ferro- and ferrimagnetic particles. Under external conditions (at a temperature of 80 K) when the e-Fe2O3 magnetic structure is incommensurate, the coercivity during the pulsed magnetization switching depends already on the parameter dH/dt and is determined, to a great extent, by the maximum applied field Hmax. Such a behavior atypical of systems of ferrimagnetic particles is caused already by the dynamic spin processes inside the e-Fe2O3 particles during fast magnetization switching.

The paper presents the experimental results of silicon cathodic arc evaporation in a continuous mode with the superimposed external arched magnetic field. Volt-ampere characteristics are obtained for arc discharge and the cathode spot velocity is determined at different external magnetic field. It is shown that the erosion rate of the silicon cathode surface depends on the magnetic field. Silicon coatings obtained by using a continuous mode of cathodic arc deposition, demonstrate the silicon droplet diameter ranging from 30 nm to 5 μm. Experiments show a decrease in the droplet number density and the volume fraction in coatings with increasing magnetic field.

The Fe3O4/CoFe2O4 nanoparticles with a core–shell structure with an average size of 5 nm have been obtained by codeposition from the iron and cobalt chloride solutions. An analysis of the magnetic properties of the obtained system and their comparison with the data for single-phase Fe3O4 (4 nm) and CoFe2O4 (6 nm) nanoparticles has led to the conclusion about a noticeable interaction between the soft magnetic (Fe3O4) and hard magnetic (CoFe2O4) phases forming the core and shell of hybrid particles.

The processing technique for microwave p–i–n diodes based on SiC (silicon carbide) has been developed. Based on these diodes, switches in the 3-cm range have been fabricated. It has been shown that the working power of the developed switches is about 10 times higher than that based on Si diodes at the same base thickness, which is equal to 5 μm. The ways of further improvement of the processing technique of these devices have been suggested.

It was clear from the outset of work on nuclear power that liquid metals are attractive coolants (small neutron absorption cross section, high thermal conductivity, etc.). The measurements of temperature fields in flows of liquid metals form the basis for obtaining reliable calculated dependences on the intensity of heat transfer. This article calls attention to the necessity of preserving this data.

The hardness of heat-resistant chromium alloy may be decreased by heat treatment. The influence of the hardness on the wear rate of alloy tools in turning is investigated.

The technology of heat treatment of a heat-resistant alloy based on chromium is developed, which reduces its hardness. The influence of hardness on the wear rate of a carbide cutting tool during turning is determined. Keywords heat-resistant alloy, turning, hardness, wear rate. akkirillov@yandex.ru

White light-emitting diodes (WLEDs) have aroused great attention due to their potential technological applications. In this work, we present two new Zn(ii) anthracene-linker-driven coordination polymers that exhibit intrinsic white-light emission. The emission covers the whole visible spectrum at room temperature. The chromaticity coordinates of the broadband emission can be tuned under external stimuli, including thermal and mechanical grinding. The obtained coordination polymer materials emit a "warm" white light at room temperature suitable for indoor lighting applications as well as a "cold" white light at the cryogenic temperature. Hence, the well-defined structures and mechanically tunable emission provide an excellent opportunity for realizing their potential as white emitters in optoelectronics.

The luminescence-intensity profiles of the bands of the first and second positive systems of molecular nitrogen were calculated for the case of the precipitation of high-energy electrons with energies from 10 keV to 10 MeV into the atmosphere. The calculations showed that the contribution of the quenching of state B3Πg N2 increases during molecular collisions with an increase in the energy of electrons intruding into the atmosphere. This leads to a decrease in the ratio of the integrated intensities of the bands of the first and second positive systems with an increase in the energy of electrons that precipitate into the atmosphere.

The effect of the γ'- and β-phase particles on the thermoelastic γ-α' martensitic transformation (MT) during cooling/heating and under stress was studied under tension and compression on the [001]-oriented single crystals of Fe-28%Ni-17%Co-11.5%Al-2.5%Ti (at.%) alloy. The effect of the aging regime on the Ms temperature was shown. Maximum increase in the Ms temperature by 100 K was found with the simultaneous precipitation of the γ'- and β-phase particles after two-stage aging of 4+4h at 873 K, in comparison with single-stage aging for 8h. In crystals with γ' and γ'+β-phases particles the difference (asymmetry) of the stresses for the stress-induced γ-α' MT σcr and value α = d σcr/ dT under tension and compression were not observed. The absence of asymmetry of the σ cr and value α = d σcr/ dT are due to close values of the shape memory effect (SME) and superelasticity (SE) under tension and compression. The values of SME and SE were decreased when β-phase particles are precipitated.

The article considers the local stability of hinged supported beams with a flexible wall, supported by paired stiffeners on the supports and loaded with a concentrated force in the middle of the span. To prevent the loss of stability of the wall from compression, another edge was installed in the area of ​​application of force. The materials considered as beams were steel, aluminum, and stainless steel. In this work, the beam material is steel C345. The study was conducted by analyzing the requirements of the Code of Practice for beams with a flexible wall in terms of the stability loss caused by the two types of deformations - shear and bending. By means of small simplifications, the requirements of the Code of Practice have been transformed into empirical dependencies convenient for practical calculations for estimating the critical loads on the beam. The finite element method with ANSYS software was used as an effective analysis tool. It has been established that in some cases the cause of loss of stability is a shift, and in others - a bend. A criterion for changing the forms of buckling was also obtained. The calculation results for the obtained dependences are in satisfactory agreement with the FEM and experimental data.

Lithium-manganese-rich–lithiated nickel-manganese-cobalt oxides are advantageous for using in lithium-ion batteries due to low toxicity and high specific capacity but suffer from low high-rate capability. In this paper, characterization and electrochemical testing of 0.5Li2MnO3·0.5LiNi0.5Mn0.3Co0.2O2 (Li1.2Ni0.2Mn0.52Co0.08O2) obtained by means of a citric acid–aided route is described. It demonstrates excellent electrochemical performance possessing specific capacity equal to the theoretical value (280 mAh g−1), being able to be discharged with currents of 2240 mA g−1 (8 C), having high coulombic efficiency (~ 99%) even after high-rate tests, and manifesting low capacity fade after high current loads and upon further cycling by 0.1 C currents (0.144 mAh g−1 per cycle).

This paper presents a mathematical model for the ultrapurification of substances via distillation in a closed vaporization–condensation system, where vapor condenses on a flowing down liquid film. We jointly analyze the mechanisms behind vaporization, vapor transport, condensation, condensate motion, and impurity diffusion in vaporizing liquid. Examining the removal of cobalt impurities from iron pentacarbonyl as an example, we assess the degree of purification as a function of vaporization and condensation temperatures, vaporization area, the fraction of liquid vaporized, and the radius and height of the condensation tube. Using experimentally determined temperature-dependent effective separation coefficients and the mathematical model, we find diffusion coefficients and equilibrium separation coefficients of cobalt, tungsten, and chromium impurities in iron pentacarbonyl.

Nuclear γ-resonance experiments with energy and time resolved detection are carried out with ϵ-F2O3 nanoparticles and a 57Co(Rh) laboratory Mossbauer source of γ radiation and a 14.4125 keV synchrotron radiation source on the ID18 beamline (ESRF) in the temperature range of 4–300 K. Both methods show a tremendous increase in the hyperfine field in tetrahedrally coordinated iron positions during the magnetic transition in the range of 80–150 K. As a result, the splitting of the quantum beat peaks in the nuclear scattering spectra is observed in the time interval of 20–170 ns with a periodicity of ∼ 30 ns. In addition, the first quantum beat is slightly shifted to shorter times. A correlation between the quadrupole shift and the orbital angular momentum of iron in ϵ-F2O3 nanoparticles is found. The magnetic transition leads to the rotation of the magnetic moment in the tetrahedral positions of iron around the axis of the electric field gradient by an angle of 44°.

It is well-known that the fraction of surface atoms and the number of defects in an antiferromagnetic particle increase with a decrease in the particle size to tens of nanometers, which qualitatively changes the properties of the particle. Specifically, in antiferromagnetic nanoparticles, spins in the ferromagnetically ordered planes can partially decompensate; as a result, an antiferromagnetic particle acquires a magnetic moment. As a rule, uncompensated chemical bonds of the surface atoms significantly weaken the exchange coupling with the antiferromagnetic particle core, which can lead to the formation of an additional magnetic subsystem paramagnetic at high temperatures and spin-glass-like in the low-temperature region. The existence of several magnetic subsystems makes it difficult to interpret the magnetic properties of antiferromagnetic nanoparticles. It is shown by the example of NiO nanoparticles with an average size of 8 nm that the correct determination of the contributions of the magnetic subsystems forming in antiferromagnetic nanoparticles requires magnetic measurements in much stronger external magnetic fields than those commonly used in standard experiments (up to 60–90 kOe). An analysis of the magnetization curves obtained in pulsed magnetic fields up to 250 kOe allows one to establish the contributions of the uncompensated particle magnetic moment μun, paramagnetic subsystem, and antiferromagnetic particle core. The μun value obtained for the investigated NiO particles is consistent with the Neel model, in which μun ∼ N1/2 (N is the number of magnetically active atoms in a particle), and thereby points out the existence of defects on the surface and in the bulk of a particle. It is demonstrated that the anomalous behavior of the high-field susceptibility dM/dH of antiferromagnetic NiO nanoparticles, which was observed by many authors, is caused by the existence of a paramagnetic subsystem, rather than by the superantiferromagnetism effect.

The present work aims at studying low-temperature steam conversion of model flare gas mixtures containing C2H6-C5H12 in methane excess over industrial Ni-based catalyst. It is shown that at 250–350 °C and H2O/CC2+ molar ratio of 0.7–1.0, steam conversion can be applied to convert C2+-hydrocarbons into CH4, CO2 and H2, which results in the lowering net calorific value, the Wobbe index and dew point temperature of the gas obtained. However, complete conversion is not necessary for certain applications. In these cases, kinetically controlled partial conversion of ethane and propane enables one to obtain methane-rich mixtures with desired calorific properties for various applications. This idea has been experimentally verified. Kinetic study of C2H6-C5H12 low-temperature steam conversion has been performed. A simple macrokinetic model, which included irreversible first-order kinetics for C2H6-C5H12 steam conversion and quasi-equilibrium mode for CO2 methanation, has been suggested. The model adequately describes the experimental data on the conversion of model flare gas mixtures at various temperatures and flow rates and has been applied to predict the reaction conditions which would allow one to obtain methane-rich mixtures with the desired properties for various applications.

Electron spin resonance in situ was applied to study the initial stages of ferrofluid formation in combination with the X-ray diffraction, high-resolution transmission electron microscopy and Fourier transform infrared spectroscopy studies data. The ultrafine (d = 4 nm) magnetite in dimethylsulfoxide ferrofluid with a narrow size nanoparticles distribution was obtained in a single step at room temperature by admixing butylene oxide to a solution of iron (II) and (III) chlorides in dimethylsulfoxide. It has been shown that at the first step of the ferrofluid synthesis antiferromagnetically ordered iron containing phase is formed, which can be correlated with iron hydroxides.

—The results of friction-wear tests of rolled friction-polymer materials (FPM) of two types using the operating modes of the friction brake of a centrifugal type roller are presented in this work. The tests were performed on the Nanovea T50 tribometer according to the pin-on-disk scheme. Experimental dependences of temperature, coefficient of friction and wear on the pressure on the friction lining have been obtained. The stability of the coefficient of friction of the FPM/Steel friction pair was evaluated. Comparison and analysis of the results have been performed and recommendations on the application are presented.

Existing conditions make possible obtaining information that being discussed openly by wide scientific community could help outlining or even establishing the expediency of a particular area of present and future research. Use link http://www.sciencedirect.com to learn about the topics or areas that most attract researchers from different countries. The Generation IV International Forum (GIF-IV) established in January 2000 has set a goal to improve the new generation of nuclear technologies in the following areas: stability, safety and reliability, economic competitiveness, proliferation resistance and physical protection. The purpose of the present publication is to prepare a discussion of one of the directions of development of fourth-generation NPPs, the groundwork for which has already been laid in thermal power engineering in various countries. The number of papers published annually on this topic is the largest among other similar topics dedicated to nuclear power plants of the fourth generation. Judging from the operating experience of existing nuclear power plants using water as a coolant, it can be ascertained that the tendency of building water-cooled nuclear power plants will remain during the next 30 to 50 years. During the present stage the task in the development of alternative types of reactors will be limited to demonstration of their performance and acceptability for future power engineering and the society. The project of supercritical water-cooled reactor is based on the operating experience of VVER, PWR, BWR reactors (more than 14,000 reactor-years); many years of experience accumulated in operating fossil thermal power plants (more than 400 power units; 20,000 years of operation of power units) using supercritical (25 MPa, 540°C) and super-supercritical (35–37 MPa, 620–700°C) water steam. In Russia more than 140 supercritical pressure units are currently in operation. Numerical calculation and design of supercritical water-cooled reactor (similarly to BR-10 reactor) will allow not only training personnel for future development of this technology, but will also help revealing the most difficult points requiring experimental confirmation with application of independent test facilities, as well as formulating the plan of first priority experimental studies. Knowledge accumulated over the last 10 years in the world allows the following: further specifying the already developed concept; developing a plan of specific priority studies; compiling task order for designing small-power pilot VVER SKP-30 reactor (30 MW-th). The scope of problems that are to be solved to substantiate VVER-SCP reactor and commence designing an experimental reactor with thermal capacity of 30 MW is the same as that in developing any type of nuclear reactor: physics of the reactor core; material related matters (primarily concerned with the reactor pressure vessel, fuel, and fuel rod cladding); thermal hydraulics of rod bundles in the near- and supercritical areas; water chemistry at supercritical pressure; corrosion of materials, development of safety systems. Research must be carried out both in static conditions and under irradiation. The absence in Russia during the extended time period of approved program with allocation of appropriate funding and preservation of the existing status during the coming two or three years will lead to the situation when Russia will be hopelessly lagging behind in the development of SCWR technology.

The ultrafine (d = 4 nm) magnetite ferrofluid with a narrow nanoparticle size distribution has been synthesized in one stage at room temperature from a solution of iron(II) and (III) chlorides in dimethylsulfoxide (DMSO) with the propylene epoxide admixture. This is the first example of obtaining a stable concentrated ultrafine magnetite/DMSO ferrofluid at room temperature. X-ray diffraction, transmission electron microscopy, ferromagnetic resonance, Mossbauer spectroscopy, and magnetostatic study have been used to elucidate the role of DMSO and the H2O/DMSO ratio in the formation of a stable colloid with a desired nanoparticle size. The initial stages of the magnetite nanoparticles formation have been investigated by the ferromagnetic resonance technique.

This paper provides the investigation of the liquid cooling system of power-electronic high-voltage assembly. There is one of the most important tasks in electrical engineering to provide the efficient cooling of different devices. In this way, the cooling of power electronic devices is very important too. The cooling system in question was designed to dissipate about 10 kW of thermal energy. Meanwhile, the electrical power rectifier in question in this paper emits near the 9 kW of thermal energy. The thermal dissipation in the cooling system much depends on the type of cool agent. The mercury was taken as a cool agent.

In this paper, the authors investigate the design features of compact high-selective microstrip filters based on structures with a significantly limited number of folded half-wave hairpin resonators. A significant number of the working attenuation poles, which is several times greater than the number of resonators in the filter, is formed in these structures with increased frequency selectivity under certain conditions. In this case, the order of this type filters transfer characteristic is determined in the passband by the number of resonators in the structure and in the stopband - by the number of working attenuation poles. This filter order feature provided a combination of low loss in the filter's passband and increased frequency selectivity over a wide stopband.

Two coordination polymers, [Co(µ4-L)(H2O)2]n (1) and [Ni(µ-L)(H2O)4]n (2), were solvothermally assembled from the corresponding metal(II) chlorides and biphenyl-4,4-dioxydiacetic acid (H2L) as a flexible dicarboxylate linker. The cobalt(II) compound 1 featured a layer-pillared 3D metal-organic network with a cds topology, while the nickel(II) derivative 2 represented a linear chain 1D coordination polymer with a 2C1 topology. The µ4− and µ-L2− linkers exhibited different denticity and coordination modes in the synthesized compounds, thus contributing to their structural diversity. The dimensionality of 1 and 2 had an influence on their thermal stability and decomposition processes, which were investigated in detail by TG-DSC and TG-FTIR methods. Thermal decomposition products of coordination polymers were also analyzed by PXRD, confirming the formation of Co3O4/CoO and NiO as final materials. The obtained compounds broaden a family of coordination polymers assembled from flexible dicarboxylate linkers.

The integration of metal-organic frameworks (MOF) into organic polymers represents a direct and effective strategy for developing innovative composite materials that combine the exceptional properties of MOFs with the robustness of organic polymers. However, the preparation of MOF@polymer hybrid composites requires an efficient dispersion and interaction of MOF particles with polymer matrices, which remains a significant challenge. In this work, a new simple and direct approach was applied for the development of Ln-MOF@polymer materials. A series of Ln-MOF@TGIC composites {Ln-MOF = [Ln(μ3-BTC)(H2O)6]n (Ln-BTC), where Ln = Eu, Tb, Eu0.05Tb0.95; H3BTC = 1,3,5-benzenetricarboxylic acid; TGIC = triglycidyl isocyanurate} were successfully obtained by applying a grinding method via the chemical bonding between uncoordinated carboxylate groups in Ln-BTC and epoxy groups in TGIC. The Ln-BTC@TGIC materials possess significant fluorescence characteristics with superior emission lifetimes and quantum yields if compared to parent Ln-MOFs. Interestingly, under the UV irradiation, a considerable color change from yellow in Eu0.05Tb0.95-BTC to red in Eu0.05Tb0.95-BTC@TGIC was observed. The energy-transfer mechanism was also rationalized by the density functional theory (DFT) calculations. The developed Ln-BTC@TGIC composites were further applied as functional fluorescent coatings for the fabrication, via a simple spraying method, of the flexible polyimide (PI) films, Ln-BTC@TGIC@PI. Thus, the present work unveils a new methodology and expands its applicability for the design and assembly of stable, multicomponent, and soft polymer materials with remarkable fluorescence properties.