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A silicon metasurface with a symmetry-protected quasi-dark resonant mode is designed and demonstrated as a refractometric sensor and tunable notch filter in the near-infrared spectrum. The resonant mode is excited by perturbing a periodic array of Si cuboids patterned on a glass substrate. Thanks to the delocalized nature of the resonant mode, intense light-matter interaction with the overlayer material is manifested. Such interaction leads to strong dependence of the resonant wavelength on the overlayer refractive index and high achievable quality factors, including the case of lossy materials. High sensitivity and figure of merit is calculated for operation of the metasurface as a refractometric sensor. In a complementary approach, three types of tunable notch filters are demonstrated, based on the use of thermo-optic, electro-optic polymers, and nematic liquid crystals.

Development of a technology for obtaining direct reduction iron from titanium-magnetite ores, which will be the main ore base of the Ural ferrous metallurgy in the future, is one of the urgent tasks of metallurgical science. The world and domestic experience of the development of direct iron reduction processes, which are the most environmentally friendly of all existing methods of obtaining iron from ore considered. It was shown that the technology of metallization of iron ore materials in the Midrex shaft furnace has received the most widespread application. It is noted that the accumulated experience of using Midrex technology in Russian Federation will allow increasing the production of metallurgical raw materials with a reduced carbon footprint. An algorithm and a block diagram for calculating technical and economic indicators of the metallization process for the Midrex process shaft furnace are described. A methodology for calculating material and thermal balance of the Midrex process has been developed, taking into account the use of iron ore raw materials containing vanadium and titanium in the charge. On its basis, an algorithm was developed and a mathematical model of the metallization process was implemented, calculations of the metallization process of titanium-magnetite pellets obtained from the ores of the Kachkanar deposit in the Midrex mine furnace were performed. A comparison of the indicators of the metallization process of titanomagnetite pellets carried out in the shaft furnace of JSC “OEMK named after A.A. Ugarov” and obtained using the created software product showed satisfactory convergence of the results.

We suggest a new graphene-based four-port circulator for THz applications that consists of two parallel graphene waveguides coupled to an elliptical graphene resonator between them. The graphene elements are deposited on a dielectric substrate. An external constant magnetic field is applied normal to the resonator. The frequency response of the circulator obtained from numerical simulations performed with COMSOL Multiphysics software is in good agreement with those obtained from the ad hoc temporal coupled-mode theory. The analysis shows that the bandwidth of the circulator is about 5.7% around the central frequency 5.03 THz with the applied constant magnetic field of 0.8 T.

One of the important tasks in carrying out a computational justification of the reliability and safety of equipment that is part of the projected nuclear power plants today is the modeling of the bubbly regime of the coolant flow. In this regard the aim of this work is the use of extended methods of using matrix conductometric systems which are widespread in research practice for study of gas-liquid flows.The work uses a method of primary processing of experimental data aimed at eliminating of excess conductivity in the cells of the developed wire mesh sensor which makes it possible to obtain the values of the true volumetric gas content in the investigated area.Subsequent analysis of the possibilities to estimate the volumes of registered gas bubbles by the gradient method as well as the size of the interface in the sensor cells which plays a key role in modeling the interfacial heat and mass transfer.Comparison of readings values with the control instruments cues showed a good agreement. The presented work is an adaptation of the use of a conductometric measuring system for the study of multicomponent flows with the aim of further application for the study of two-component flows in the channels of the core simulator using wire mesh sensors.

The features of cracking catalysts produced by aluminosilicate technology are described. Approaches to designing cracking catalysts for processing various types of materials (light, heavy, mixed) are shown. The main methods for modifying components and properties of catalysts prepared on their basis are presented. Methods for reducing catalyst activity in hydrogen transfer reactions (for catalysts prepared by aluminosilicate technology) are shown. The achievable yields of olefins on the described catalysts are 35 and 50 wt.% at processing heavy and light feedstock types respectively. The influence of the feedstock hydrotreating degree on the yield of light olefins is considered.

The paper proposes a method for processing acoustic emission signals for calculating informative signal parameters characterizing the stages of plastic deformation and fractures in a loaded titanium alloy. The proposed method has a complex structure that includes digital signal processing algorithms and multivariate data analysis methods. The acoustic emission signals are processed using the mathematical apparatus of the multilevel discrete wavelet transform to obtain the approximation coefficients of the 10-level decomposition. These coefficients characterize the low-frequency features of acoustic emission at various stages of samples loading. The approximation coefficients are further used as informative parameters of acoustic emission signals. Principal components analysis is used to investigate the informative parameters and establish their quantitative relationship with the stages of plastic deformation of titanium by clustering the processed results. Differences in the informative parameters at different stages of plastic deformation of the material are revealed by the following analysis of the clustered results. The obtained results can be used to develop a new generation of diagnostic devices for acoustic emission measurements., Предлагается метод обработки сигналов акустической эмиссии для вычисления информативных параметров сигнала, характеризующих стадии пластической деформации и разрушения в нагруженном титановом сплаве. Представленный метод имеет комплексную структуру, включающую применение алгоритмов цифровой обработки сигналов и методов многомерного анализа данных. В основе предлагаемого подхода к обработке акустической эмиссии лежит применение математического аппарата многоуровневого дискретного вейвлет-преобразования сигналов. С помощью вейвлет-преобразования получены коэффициенты аппроксимации 10-уровня разложения, которые характеризовали низкочастотные особенности акустической эмиссии на различных этапах нагружения материала. Коэффициенты аппроксимации использовались в качестве информативных параметров сигнала. Для анализа информативных параметров и установления их количественной связи со стадиями пластической деформации титана привлечен метод главных компонент. На основе результатов кластеризации выявлены различия в информативных параметрах на разных стадиях пластической деформации материала. Полученные результаты могут быть использованы при разработке нового поколения устройств диагностики, использующих акустико-эмиссионные измерения.

The evolution of the stress state of shell forms by the smelted models under a nonstationary external thermal action, mainly when pouring liquid metal into cold casting shell molds, is studied.

In plasma devices, in which plasma–wall interaction and material migration are significant, the diagnostic-window transmission may decrease due to the contamination of plasma-cleaning components by sputtered materials. We discuss the cleaning of KU-1 fused silica, which simulates the diagnostic window, from aluminum films in RF plasma generated in pure H2(D2) and Ne and in H2(D2)–0.23Ne mixtures. Aluminum is used as a chemical analogue of Be, which is the main material of the International Thermonuclear Experimental Reactor (ITER) first wall. The morphology of the plasma-treated surface is investigated by atomic force microscopy, the chemical composition is analyzed by X-ray photoelectron spectroscopy, and the transmission spectra in the range 400−1000 nm shows that plasma cleaning is accompanied by the slight reduction of quartz to suboxides and a simultaneous decrease in roughness Rq from 1.3 up to 1.0 nm. After plasma treatment of the quartz surface, a decrease in light transmission by 1.5–2% in the wavelength range 400–750 nm is observed. Further sputtering of the purified quartz surface with the removal of a layer with a thickness of more than 300 nm is accompanied by gradual smoothing of the surface and a decrease in Rq to 1 nm, but with the retention of reduced light transmission. All investigated gases, hydrogen isotopes, neon and D2(H2)–Ne mixtures, are suitable for removing Al films from the quartz surface at a RF power of several W/cm2 and temperatures of 20–100°C.

An algorithm is proposed for constructing curves of thermal cooling and ordering kinetics with a monotonic decrease in temperature for alloys to stoichiometric composition. Modeling is carried out by the Monte Carlo method in the model of a rigid crystal lattice and pair interatomic interactions. The application of the algorithm is illustrated by the example to a square lattice, taking into account interatomic interactions in the first two coordination spheres for alloys with the composition AB, A3B, and A3B5. The proposed model makes it possible to calculate individual sections of the phase diagrams to the state for binary alloys.

The papers devoted to the purification of aquatic environments from industrial contaminants with the use of ZnO based nanosized photocatalysts in the period of 2018–2020 are analyzed. The data published in these papers have made it possible to determine the dye (V) destruction rate used further as a photocatalytic activity criterion. As shown by the comparative analysis of the photocatalytic activity of the studies structures, the highest rates of water purification from industrial azodye contaminants are demonstrated by hybrid ZnO/Au structures. At a destruction rate of V = 10%/min, the ZnO/Au structures are much better than all the other considered types of catalysts due to their morphology, low recombination rate of photogenerated electron-hole pairs, and nanoparticles with an absorption spectrum close to the solar spectrum. The review of literature data shows that the greatest attention of researchers in the considered time period is focused on the problem of the purification of water sources from industrial contaminants and, first of all, azodyes. Essential attention is also paid to the technological approaches applied by the authors to increase the photocatalytic activity of ZnO based nanostructures.

The paper presents the results of investigations into the hydrodynamics of a three-dimensional coolant flow motion in the mixed core of a VVER (a.k.a. WWER or PWR) reactor. The experiments were conducted on an aerodynamic research facility test bench with scaled models of core fragments. An investigation has been made into the patterns of the coolant flow motion by experimental finding of the velocity vector. Measurement of the flow pressure field was conducted with a five-channel pneumometric (pressure-tube) probe and was then recalculated and converted into the direction and value of the velocity. To obtain a detailed pattern of a three-dimensional coolant flow motion, the most representative region of the models′ cross section including the space between the fuel (fuel rod bundles) and four rows of fuel elements of each of the adjacent fuel assemblies was identified and investigated. The general pattern of the coolant flow is represented by plots of transverse velocity distribution as a function of a relative coordinate and by cartograms of axial velocity distribution. An analysis of the spatial distribution of the flow velocity projections in characteristic regions of the model made it possible to identify the patterns of the coolant flow around hydraulically nonidentical intensifier grids.

We analyze disadvantages of the available designs of devices aimed at filling the crystallizers with liquid metal and their elements. In order to increase the intensity of mixing of the metal and, hence, to get homogeneous structures of the crystallized metal and guarantee the conditions of safe operation of the personnel, we propose to use an absolutely new design of the device used for the delivery and mixing steel in the crystallizer. The proposed design of a device in the form of a submersible nozzle with reflector placed on a bracket is much simpler and less costly in manufacturing and operation than the well-known complex analog in the form of a deep-flow submersible nozzle with outlet holes.

Solution-combustion synthesis of NixCo3 – xO4 (x 0.9) led to an increase in reaction temperature and the formation (after annealing at 400°C) of non-stoichiometric spinels NixCo3 – xO4 (x < 1) with an admixture of double oxides NiyCo1 – yO (y = 0.71–0.77).

In this work, a nanoscale structure consisting of contacting layers of a metal of the iron subgroup and a rare earth metal oxide (REM) is considered. Such nanostructures have an interesting feature, which is that as a result of the contact of these layers, an increase in the galvanomagnetic, magneto-optical and kinetic properties of ferromagnetic metals are observed. Presumably, the enhancement is due to an increase in the magnetization of these metals, caused by the exchange f - d interaction between the unfilled f- and d-electron shells of the atoms that make up the contacting layers. The aim of this work is to find the possibility of such f - d exchange interaction by the EPR method. To compose the studied nanostructure, Fe used as it has the strongest magnetic properties in its subgroup. Gd2O3 was used as an REM oxide as one of the few oxides giving a significant signal in the EPR region. The Gd2O3/Fe nanostructure created by sequential electron-beam deposition of Gd2O3 and Fe layers on a sitall substrate. The thickness of the oxide and metal layers was 68 and 112 nm, respectively. EPR spectra were recorded at room temperature on a computerized spectrometer Radiopan 2547 SE / X at the frequency of 9.3 GHz. The set of the obtained spectra was processed using the OriginPro and MatLab programs, which confirmed their compliance with the Lorentz model. From the experimentally obtained EPR linewidth, the parameter of the exchange f - d interaction is determined under the condition of a number of assumptions. The value of the g-factor is also found. Comparison of the EPR parameters of the spectra of individual layers of Gd2O3 and Fe with the spectra of the Gd2O3/Fe nanostructure composed of them, including the value of the g factor and the exchange interaction parameter, suggests that the presence of an iron layer affects the EPR spectrum of the REM oxide layer Gd2O3. The exchange interaction parameter increases from 985 to 4685 (rel. units), the g-factor decreases from 3.5 to 2.4. The most probable reason for the change in the spectrum is the exchange f - d interaction between atoms with unfilled f- and d-electron shells that are parts of the contacting layers.

The paper contains a review of the main technologies used for producing metal powders for 3D printing. The prospects are shown for the development of an energy-saving technology for mechanical spheroidization of metal powders using metal processing waste and vibration effects. The results of respective experiments are presented.

A model of the processes in a galvanic bath during heating is based on the finite element method. The processes of heating the air chamber and directly the reagent solution are simulated. Based on the constructed model, an automatic control system for heating elements is being developed, which provides a sufficient heating rate, a stable temperature and protects the heating elements from burnout. An application program has been created that allows performing the calculations without studying complex modeling systems.

Experimental studies of the flow of liquid metal in CCM mold are long, complex and labor consuming process. Therefore, mathematical modeling by numerical methods is increasingly used for this purpose. The article considers a new technology for liquid metal supply into a mold. The authors present original patented design of the device, consisting of direct-flow and rotating bottom nozzles. The main results of investigations of the melt flow in the mold are considered. The objects of research were hydrodynamic and heat flows of liquid metal at new process of steel casting into a CCM mold of rectangular section. The result is spatial mathematical model describing flows and temperatures of liquid metal in the mold. To simulate the processes occurring during metal flow in the mold, special software was designed. Theoretical calculations are based on fundamental equations of hydrodynamics, equations of mathematical physics (equation of heat conduction taking into account mass transfer) and proven numerical method. The area under study was divided into elements of finite dimensions; for each element, resulting system of equations was written in difference form. The results are fields of velocities and temperatures of metal flow in the mold volume. A calculation program was compiled based on developed numerical schemes and algorithms. An example of calculation of steel casting into a mold of rectangular cross-section, and flow diagrams of liquid metal along various sections of the mold are given. Vector flows of liquid metal in different sections of the mold are clearly presented at different angles of rotation of the deep-bottom nozzle. The authors have identified the areas of intense turbulence. Metal flows of the described technological process were compared with traditional metal supply through a fixed bottom nozzle.

Basing on the analysis of the physical features of the operation of the microphone on electrokinetic phenomena, it has been experimentally confirmed that this microphone works on a functional principle different from the principle of operation of a condenser microphone. It is shown that a microphone based on electrokinetic phenomena can increase its sensitivity by up to about 40 dB due to pumping. Comparison of two experimental studies shows that the sensitivity of an electrokinetic microphone can strongly depend on the size of the porosity of the dielectric placed between the electrodes of the microphone.

In the approximation of a thin double layer, simple dependences of the acoustic fields excited in an electrokinetic electroacoustic transducer on the velocity of the Helmholtz—Smolukhovsky osmotic movement are obtained. From the dependencies it follows that in the absence of losses, when the nonlinearity of the fluid motion equation does not yet affect and there is no turbulent mode of fluid motion in the transducer body, the magnitudes of the amplitudes of the acoustic velocity and pressure linearly depend on the magnitude of the Helmholtz—Smolukhovsky electroosmotic motion velocity.

This work is an experimental study into the hydrodynamics of the coolant flow in the in-vessel pressure duct of a pressurized water reactor. In the article, an experimental testbench and a nuclear reactor model under investigation are described, the measurement methods are set forth, and the operating variables at which the study was conducted and the obtained results are provided. In the experiments, the mixing of the loop coolant flows inside the model of the nuclear reactor downcomer was simulated. The study was conducted on the high-pressure aerodynamic testbench of Alekseev State Technical University in Nizhny Novgorod. The scale model of the nuclear reactor had the structural components characteristic of loop-type reactor units, such as the annular downcomer and the bottom pressure vessel. The experiments were conducted at Reynolds numbers within the 20 000–50 000 range measured in the annular gap of the downcomer of the model. The axial velocity field at the inlet to the reactor core simulator was investigated using a pneumometric probe. The temperature field was recorded in the experiment by the impurity diffusion method, i.e., by introducing of a contrast tracer into one of the loops of the model. The degree of mixing the flows was estimated by the admixture (tracer) concentration at the inlet to the core simulator. Propane was used as the contrast admixture. The study has yielded the spatial distribution of the tracer in the coolant flow in the annular downcomer and in the bottom pressure vessel. The data on the distribution of the contrast admixture are presented in the form of charts. The swirling of the coolant flow in the in-vessel pressure duct has been analyzed. It has been shown that the mixing intensity in the bottom pressure vessel is affected by the central vortex with the central axis. The parameters of mixing the admixture in the model of the in-vessel pressure duct have been estimated.

Variable-pitch multifinned seals (VPMS) have not hitherto found wide use in the steam turbines produced in Russia, although they are quite often used outside of Russia. In modernizing the existing and designing new steam turbines, rotor blades with an integrally machined shroud are used, which opens the possibility to manufacture multirow peripheral seals. In this connection, the question about selecting the optimal VPMS configuration becomes of important practical significance. The results obtained in this study made it possible to experimentally estimate the extent to which different combination of fin pitches on the rotor and stator influence the VPMS discharge characteristics and to elaborate practical recommendations on using them. The minimal leak flow was recorded for the VPMS models with a 2-mm-wide pitch on the rotor. Comparative experimental investigations of VPMS models with 3- and 4-mm-wide spacers on the rotor and 4- and 5-mm-wide spacers on the stator were carried out as applied to the shroud seals of large-capacity steam turbines. The model pair with the 4- and 5-mm-wide spacers on the rotor and stator, i.e., with the pitches equal to 4.8 and 5.8 mm on the rotor and stator, respectively, can be regarded as the most optimal of those investigated in this work. It has been shown experimentally that, with all other things being equal, the leak in VPMSs is by 22–25% smaller than it is in straight-flow seals. By using VPMS, it becomes possible to avoid rubbing of the rotor against the stator under the conditions of relative radial and axial rotor displacements in transient modes of operation. In addition, the aerodynamic forces in VPMS able to excite a low-frequency shaft line self-oscillation are approximately equal to 60% of the similar forces occurring in the conventional radial clearance seals. In view of this circumstance, VPMS can be recommended for use instead of the standard tip shroud seals in the high- and intermediate-pressure cylinders in new and modernized steam turbines.

Questions about the oxidative roasting of iron ore raw materials (agglomerates and pellets) are studied. Features of the phase structure of the iron ore raw materials containing titan and vanadium are discussed. Reducibility, durability, and the softening and melting temperatures of metallurgical iron ore raw materials are studied in vitro. The objects of the research are titaniferous ores containing different amounts of titan dioxide. The behaviors of agglomerates and pellets in a blast furnace are studied, and the influence of their physical and chemical properties on heat and mass transfer processes are researched by means of a mathematical model. The main indices of blast furnace smelting—productivity, coke consumption, composition of top gas, cast iron, and slag—are shown. It is established that the increase in titanium dioxide content in pellets, as the amount of concentrate with increased TiO2 content increases, does not cause deterioration in the quality of iron ore raw materials being prepared for blast furnace smelting. At the same time, as the hot strength of raw materials increases, the temperature at which softening begins increases and the temperature interval of softening of materials decreases.

Fundamental new features and physical nature of possibilities for purposeful influence of interrelated variations in different experimental conditions on changes of the selectivity of sensitivity of azimuthal dependence of the total integrated intensity dynamical diffraction to various types of defects in single crystals have been determined. As a result, the efficiency of the previously developed phase-variation principles of diagnostics has been improved. The proposed approach enabled us to demonstrate the presence of additional types of defects in the single crystals under study and to determine the defects parameters (sizes and concentrations). It makes it possible to obtain additional sensitivity and informativeness for phase-variation structure multiparametrical non-destructive diagnostics of monocrystalline systems with defects of various types.

The results of studies of thin Ni–Al films obtained by the resistive thermal evaporation method and having characteristic island sizes of 700–1000 nm with a film thickness of ~500 nm are described. A brief description of the method for producing a film using an installation for creating a high vacuum and subsequent film deposition is presented. The obtained film sample was studied with an optical microscope, a scanning probe microscope, and a Fourier analyzer. The kinetic characteristics of the film, its film, and the characteristic sizes of the islands have been established; regularities in the island structure of the films were sought, and its electrical conductivity has been determined.

The metallurgical characteristics of pellets (reducibility, strength after reaction, softening start and end temperatures), phase composition (X-ray phase analysis), and porosity were studied. Blast furnace smelting parameters were calculated using laboratory pellets with different basicities and degrees of metallization. Pellets were obtained from complex titanium-magnetite ores. The vanadium extraction of this ore into metal did not exceed 10 % during smelting of metallized pellets in an arc steelmaking furnace, but special techniques could raise this to 85 %. According to calculations from the Institute of Metallurgy of the Ural Branch of the Russian Academy of Sciences (IMET UB RAS), vanadium extraction up to 80–90 % can be achieved by using high-base and partially metallized pellets. The influence of changes in the composition and metallurgical characteristics of titanomagnetite pellets with increasing basicity (especially relative to strength after reduction) should be taken into account.

The results from studying the coolant flow in fuel assemblies downstream of mixing spacer grids of a PWR reactor are presented. The aim of the study is to estimate the effect from using different designs of mixing grids. For this purpose, experimental investigations were carried out on an aerodynamic test facility with scaled models of fuel assembly fragments containing mixing spacer grids of different designs. Two adjacent cells of the guiding channel zone were selected as the representative study area. The specific structural feature of these cells is that the turbulizers installed on the intensifying grids have different spatial orientation. The general flow pattern is represented by the vector fields of tangential velocities and by the distribution of relative velocities in the gaps between the fuel rods and the guiding channel. For estimating the effect from using the grid designs with respect to coolant flow mixing, the intracell vortex formation coefficients and intercell mixing coefficients were analyzed. It has been shown from the performed analysis that, owing to the use of the alternative design with a pair of cell deflectors oriented in a changed direction, the intercell transfer coefficient and the intracell vortex formation coefficient were increased by a factor of 1.13 and 2.2, respectively, in comparison with those in the basic design. Hence, the use of the grid of the alternative design is more preferable for obtaining better mixing of the coolant flow. The accumulated database on coolant flow in the Square FA serves for engineering substantiation of the PWR reactor cores. The results from experimental studies are used for verification of CFD codes developed both in Russia and abroad and of programs for detailed cell-wise analysis of the cores for reducing the conservatism in substantiating their thermal reliability.

The effect of a high-frequency discharge on the change in the topography of the surface of KU-1 optical quartz and transmission of visible light (400–1000 nm) is studied. The working gases of the discharge are D2 and a D2/N2 mixture, in which the fraction of N2 is 25 mol %. The addition of nitrogen increases the rate of sputtering from 60 to 300 nm/h without changing the stoichiometry of the surface layers. After the exposure in plasma, the root-mean-square roughness of the surface decreases from 1.3 to 0.6 nm. The transparence of quartz remains unchanged. The analysis of the roughness and calculation of the diffuse light scattering with a wavelength of 400 nm after passing through quartz are executed using the power spectral density functions.

A model of a thermal vacuum system (thermostat) for regulation and stabilization of temperature of the primary mirror of a cooled optical collimator for carrying out tests of optoelectronic equipment operating in the infrared region is designed. An original method for solving the system of nonlinear equations of radiative heat transfer in a thermostat is developed, and the uniformity of the temperature distribution over the primary mirror surface is analyzed.

The results from experiments for studying the effect of rotor rotation on the leakage through different types of seals are presented. It is shown from a comparative study of models involving a stalled rotor and rotor rotating with a 50 Hz frequency that the rotor rotation has hardly any effect on the leakage flowrate, so that the rotation may not be taken into account in calculations of leakage flowrate through the steam turbine end and diaphragm seals. The article presents results from experiments for studying the dependence of leakage flowrate on the flow parameters, namely, the change of the velocity vector axial and circumferential components in the annular inlet channel upstream of a single annular throttle orifice. During the experiments, the velocity axial and circumferential components were varied independently and in a very significant range. The accomplished studies have shown that the change of both the axial and circumferential velocity components has hardly any effect on the leakage flowrate. It can be concluded from an analysis of the obtained results that the influence of flow parameters upstream of the seal on the leakage flowrate is so insignificant that its neglect in the previously developed calculation procedures for determining the leakage flowrate in the steam turbine seals, which are still in use at present, is quite substantiated and justified. At present, studies are being carried out that allow the flow structure in different places of turbine machinery flow paths, including the turbine seals, to be analyzed by calculation. It should be noted that it is possible by using the modern calculation methods not only to determine the vortex structure in the seal neighborhood but also to estimate the leakage flowrate, leakage losses, and even the stage efficiency for different configurations of the chamber upstream of the seal. Nonetheless, care should be taken in dealing with practical recommendations on changing the seal configurations that are based solely on the calculation results. The soundness of such recommendations must be confirmed by the relevant experimental investigations.

The fracture behavior of Ti0.45Al0.55N coatings under uniaxial tension was investigated at different scale levels. The coatings were deposited on 12Cr18Ni9Ti steel substrates by direct current reactive magnetron sputtering. According to molecular dynamics simulation, the nonuniform distribution of aluminum in the coatings affects the initiation and growth of cracks in them. It was found experimentally that the macroscopic fracture of Ti0.45Al0.55N coatings on a metal substrate under uniaxial tension occurs in four stages, whose duration is determined by the competition between different stress relaxation mechanisms. The effect of the coating thickness on the development of competing deformation and fracture mechanisms in the coatings is demonstrated.

The purpose of the study is to conduct experimental studies of oil -water emulsion separation in a rectangular separator in the range of velocities along the device working area from 1.43 to 2.5 m/s. The efficiency of emulsion separation is determined by an experimental method based on measuring the density of a two-phase liquid, provided that the density of each component of the mixture is previously determined. The authors propose to use a device with U-shaped elements to increase its performance when separating oil-water emulsions. The device under study including two rows of U-shaped elements consists of one complete separation stage. The authors have conducted experimental studies of the device with U-shaped elements on the "oil-water" system, during which the efficiency of emulsion separation was evaluated. It was detemined that the proposed device provides the highest efficiency of emulsion separation of 68% when the diameter of the holes intended for the exit of the heavy phase equals to 2.5 mm in the range of emulsion velocities from 1.43 to 2.5 m/s. The conducted experimental studies will allow to use a turbulence model for calculation in the programs like Ansys Fluent or FlowVision, which will most adequately describe the separation process of similar emulsions. The experiments have proved the possibility of obtaining high values of efficiency. Therefore, the correct selection of technological parameters (average flow rate, concentration) and the size of the characteristic elements of the proposed device will allow to specify the design of a rectangular separator, for example, to calculate the number of stages to achieve the required separation efficiency or to determine the size of the separation elements.

The distribution of microhardness in cylindrical samples formed from industrial iron-based powders and not subjected to sintering is experimentally studied. This distribution is described by a simple mathematical model. It is shown that the measured hardness has a significant correlation with the strength. Microhardness is correlated with the local strength. Because, during the subsequent sintering and heat treatment of the powder sample, phase transformations occur within the individual grains, the microhardness distribution that occurs before the sample is sintered will remain after sintering. The technology of microhardness equalization in the sample at the stage of its forming, before sintering, is described.

A comparative study of the application of membrane, electromembrane and electrobaromembrane technologies for various industries in the field of wastewater treatment and technological solutions is presented. The principle of classification of membrane separation processes is formulated. The characteristic periods of the solvent transfer stimulation were determined. Based on the experimental data obtained on the permeability of the solvent through the MGA-80P and MGA-95 membranes, empirical dependences are proposed that describe the kinetic characteristics of the dependence from transmembrane pressure and temperature effects.

A method for obtaining a wholly polymeric piezoactive material based on porous poly(vinylidene fluoride) films and a conducting polymer polypyrrole is developed. Polypyrrole layers on the surface of porous substrates are formed by in situ oxidative polymerization from a pyrrole solution. It is shown that the relief structure of the surface of porous poly(vinylidene fluoride) films provides a high adhesion of polypyrrole layers to the substrate. It is found that the content of polypyrrole in the composite increases with an increase in the porosity of the substrate. Using electron microscopy, it is demonstrated that the surfaces of the composite samples are coated with a polypyrrole layer and have a globular morphology characteristic of this polymer. It is shown that the highest values of conductivity (σs = 101 S/cm and σv = 10–7 S/cm) are achieved when a methanol–water mixture is used as a solvent in pyrrole polymerization. The mechanical characteristics of poly(vinylidene fluoride)–polypyrrole composites remain almost the same as the corresponding values of the initial poly(vinylidene fluoride) substrate. Polypyrrole layers deposited on a porous substrate are used as electrodes for polarizing composites in a constant electric field and for measuring the piezoelectric modulus. The achieved values of the piezoelectric modulus d31 are about 20 pC/N.

The paper presents a mathematical model for optimizing shell mold (SM) material selection process to ensure the greatest crack resistance during liquid metal pouring. Minor elastoplastic deformation theory and heat conductivity equations as well as approved numerical methods are used to solve this problem. Objective function “min–max” has been developed based on control variables characterizing shell mold material properties. The paper considers axially symmetrical SM heating process during liquid metal pouring. SM resistance is evaluated based on occurring stress. An algorythm for solving this problem has been developed.

The design of specialized press applicable to extrude parts such as deep cups and bushings in which creating actively directed contact friction stresses at the boundary of the workpiece with the matrix, which reduces the pressure on the punch and increases its fatigue resistance is presented. The role of the non-uniformity of contact friction, which leads to different thickness of the products wall, is explained. It is experimentally proved that there is no difference of wall thicknesses when the two-channel flow of the extruded metal is happens. The results of the study of specific forces and product shaping during two-channel extrusion of parts in the form of coaxial double bushings are presented. For such parts, extrusion with actively directed contact friction stresses between the workpiece and the tool is studied. The rational combination of two bushings of different sizes into single stamped part, carried out in order to increase the productivity of stamping, is considered.

The achievable density of the workpieces under all-round static compression of the compacting iron powder is analyzed. The schemes of forming billets with a shift of powder particles are described, including during magnetic-pulse processing of the powder and the billet being formed. A mathematical model of the orientation of iron powder particles in cylindrical billets molded with intense shears between the particles is presented. Rational angles of orientation of particles are recommended in the manufacture of cylindrical parts with uniformly distributed properties in the cross section or with the greatest strength near the outer surface.

The limited use of cold volume stamping for the production of parts only for narrow traditional range of such parts in mass and large-scale productions is shown. Original technological techniques that improve the quality of products and the punches fatigue resistance are developed to expand the application of this technology to new types of parts. Such techniques used at various stages of the production process by cold forging of deep steel glasses are described. The value of rational design of stamps and the example of design of well-proven production stamp are shown.

The quest to improve the density, speed and energy efficiency of magnetic memory storage has led to the exploration of new ways of optically manipulating magnetism at the ultrafast time scale, in particular in ferrimagnetic alloys. While all-optical magnetization switching is well-established on the femtosecond timescale, lateral nanoscale confinement and thus the potential significant reduction of the size of the magnetic element remains an outstanding challenge. Here we employ resonant electromagnetic energy funneling through plasmon nanoantennas to influence the demagnetization dynamics of a ferrimagnetic TbCo alloy thin film. We demonstrate how Ag nanoring-shaped antennas under resonant optical femtosecond pumping reduce the overall demagnetization in the underlying films up to three times compared to non-resonant illumination. We attribute such a substantial reduction to the nanoscale confinement of the demagnetization process. This is qualitatively supported by the electromagnetic simulations that strongly evidence the resonant optical energy-funneling to the nanoscale from the nanoantennas into the ferrimagnetic film. This observation is an important step for reaching deterministic ultrafast all-optical magnetization switching at the nanoscale in such systems, opening a route to develop nanoscale ultrafast magneto-optics., Bottom-up produced optical ring-shaped Ag nanoantennas efficiently funnel electromagnetic field of a femtosecond-pulsed laser light into a ferrimagnetic TbCo nanofilm at plasmon resonance. This leads to the TbCo demagnetization at the nanoscale.

An exact solution of the problem on the dynamics of separation of a gas mixture in membrane separators of different designs has been obtained. A procedure for interpreting the time dependence of the pressures on different sides of a selectively permeable membrane for determining the coeffi cients of its permeability is proposed. The direct and inverse problems on determination of the parameters of membrane separators were posed and solved. It was established that the accuracy of determining the permeability coefficients of a selectively permeable membrane depends on the duration of an experiment.

This article deals with the problem of heat energy transfer from a steam-gas mixture with a constant temperature of 220 °C. An experimental study of the transfer of heat energy from a steam-gas mixture by a recuperative heat exchanger with a ribbed surface at the industrial enterprise “PULP Invest”, located at the production site of the industrial park Technopolis “Khimgrad” in Kazan, is presented. The design of a heat exchanger with a ribbed surface is described. The finned surface of the recuperative heat exchanger allowed intensifying the transfer of heat flow, due to the appearance of turbulent vortices of the vapor-gas medium when it moves between the transversely arranged fins. For a heated heat carrier, water was used, which in the future is planned to be used for technological and economic needs. This paper presents the experimental method and measuring instruments. During the experiments, the initial temperature of the cold coolant (water) varied from 28.8 to 31.9 °C. The series of experiments included 7 experiments with a different volume flow of water from 60 to 120 liters/hour. The initial volume flow rate was 60 l/h, the flow rate change step was 10 l/h. The results of the studies showed that the time of the output of the studied parameters: temperature head, heat flow and heat transfer coefficient to the stationary mode was 265 s. When entering the stationary mode with a volume flow rate of cold coolant in the range from 60 to 120 l/h, the temperature head varied from 32.2 to 63 °C, the heat flow varied from 4.1 to 4.5 kW, the heat transfer coefficient varied in the range of 24.4-27.9 W/(m2 · K). The obtained results allowed establishing that the heat transfer coefficient is inversely proportional to the thermal resistance of the vapor-gas phase.

The article describes the location where the Early Bronze Age ceramics was discovered during the study of the Petrovka Culture mound-enclosure in the Singkibay-2 burial ground in Central Saryarka. Based on analogies and a series of radiocarbon dates from the sites of the region, the analysed pottery can be attributed to the Elunino archaeological culture, and dated to the second half of the 3rd mil. BC. At the present state of the source base, the question of the nature of the location still remains open. Perhaps, it represents the evidence of the funeral-commemorative activities of the pre-Andronovo “population”, or a part of the destroyed cultural layer of the settlement. Only further field work will could address this issue. In general, this find significantly expands the distribution of the Elunino Culture to the south, which over time will possibly be extended further all the way to the northern coast of the Lake Balkhash. The recorded joint positioning of the Elunino and Petrovka materials provides the additional topographical information for the area of the pre-Andronovo complexes and puts forward the issue of the relationship between these two cultural formations. Keywords: Central Saryarka, Taldy River, early Bronze Age, Elunino Culture, location, ceramics, migrations

The article considers the possibility of modeling the kinetic characteristics of the curing process of polymer composites (for example, carbon fiber reinforced plastic) based on the use of artificial neural networks. Using neural network modeling, the dependence of the change in the kinetic function of the polymer composite on the degree of cure has been obtained. The performance of the neural network is compared with experimental data using classical approximation methods.