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The 2D code developed by the authors for calculating the penetration of neutral particles from the chamber wall to the center of the plasma created and confined in the L-2M stellarator has been verified. In the range of operating plasma densities (1 × 1019 m–3 < ne < 3 × 1019 m–3), good agreement with the results of calculations performed using the ASTRA code has been obtained. The 3D and 4D simulations of the penetration of neutral particles from the chamber wall to the central plasma region have been performed. It has been shown that the 2D simulations overestimate the concentration of neutral particles in the plasma central region, as compared to the 3D and 4D models, which use ion velocity distributions closer to the real one. [ABSTRACT FROM AUTHOR]

The process of depletion of ores accompanied by a permanent increase in the production and consumption of nonferrous metals led to the formation of a continuous shortage of copper rolled products and wire rods in the world economy and trade. To compensate this shortage, secondary raw materials, including, in particular, scrap and wastes of the cable and wire production and civil engineering, are now actively introduced in the commercial production. For this purpose, special equipment and installations were created for cable stripping, i.e., for the separation of cables into metal concentrate and plastic waste. However, the existing technologies of cable cutting, parallel with high levels of dust and noise, are characterized by significant losses of the metal (up to 32%) and low quality of finished products (containing at least 7–8% nonmetallic fraction represented mainly by the protective cable insulation). The indicated protective insulation is based on flexible polyvinyl chloride plastics and special admixtures aimed at increasing the ductility of the cable. In a melting furnace, the insulation ignites and releases into the furnace atmosphere H2, O2, Cl2, HCl, H2O, CO, and CO2, volatile hydrocarbons, and their chlorinated derivatives (chlorides, oxides, tetrahydride, tetramethyltin, etc.), which dissolve in the melt and may increase the concentration of hydrogen and oxygen in it. For this reason, we think that the concentrate obtained as a result of cable stripping is unsuitable for smelting copper and copper-based alloys. It can be used for smelting rough copper ingots, which requires the procedure of repeated refining remelting. In this connection, modern environmentally friendly cable-cutting technologies are developed with an aim to increase the degree of extraction of the main product (metal core) and improve its quality. The present work is devoted to the study of environmentally friendly recycling (firing) of cable scrap with polyvinyl chloride (PVC) insulation by the method of steam gasification. It was experimentally established that the indicated method makes it possible to obtain a concentrate, which is practically free of PVC insulation and suitable for smelting branded alloys. The application of the steam gasification method for recycling cable scrap and PVC-insulated wastes guarantees 100% yield of the volatile fraction at the temperatures of firing of raw materials lower than the temperatures corresponding to the pyrolysis mode. At the same time, the minimum losses of metal caused by its oxidation in the course of gasification are guaranteed. By processing the experimental data, it was established that, within the temperature range 475–600 °C, the process of steam gasification of PVC cable insulation is controlled by its duration, temperature, and the flow rate of the steam-air mixture. An empirical dependence that can be used to describe this process is obtained in the form f(Xi) = 3.74∙(−0.1093τ + 63.356)·(−65.594T + 63.356)·(−2.4626η + 35.577). It is experimentally established that the balance efficiency of copper extraction from the PVC insulation by the steam gasification method is not smaller than 99.92%. [ABSTRACT FROM AUTHOR]

Plasma was heated at the second harmonic of electron cyclotron resonance (ECR) in the L-2M stellarator and the T-10 tokamak. The concept of equivalent tokamak and stellarator discharges was extended to the case of both full and partial absorption of EC power. Comparison of experimental electron temperature profiles with profiles calculated using the canonical profiles transport model allows us to estimate the efficiency of ECR heating in the L-2M discharges without suprathermal electrons, which distort the distribution function, preventing reliable measurements of temperature. The dependence of the ECR heating efficiency on the plasma density was obtained, describing experiments on the L-2M and TJ-II stellarators, and on the T-10 tokamak. The energy characteristics (the stored energy and the confinement time) for L-2M discharges were calculated. Predictions for ECR heating in the T-15MD tokamak are considered. The features of solving the ill-posed transport problem for the L-2M are discussed. [ABSTRACT FROM AUTHOR]

Among the species of the genus Crotalaria L., Crotalaria juncea is the only cover crop cultivated for its fiber. The quality of the latter depends on the nutritional conditions, accumulation of biophilic elements in the biomass, and synthesis of proteinogenic amino acids. Thus, the purpose of this study was a qualitative and quantitative assessment of the green harvest at the active flowering stage, before the bean formation phase, when the entire biochemical cycle of the plant is reconfigured, and the biochemical indicators are maximum. The plants were grown for 140 days (from April 22 to September 9, 2023) in protected soil conditions. The experimental design consisted of two units of 50 plants each: in the first (control) unit, plants were grown in a soil mixture without any additives; in the second one, they were treated three times during the growing season with an organic suspension of humic acids (1000 ppm) obtained from sapropel (Pskov oblast, UDHSS) by applying it when watering at the root. The soil substrate in both cases was typical chernozem (Kamennaya Steppe Nature Reserve, Voronezh oblast, 51°01′41.6″ N, 40°43′39.3″ E) with a 20% addition of volcanic zeolite. Over the course of every 14 days, morphometric trends of the crop growth (height and dry biomass) were systematically recorded with the removal of five cultivars from each unit of options. After 140 days, the remaining five replicates per option were subjected to biochemical analysis by inductively coupled plasma mass spectrometry (ICP-MS) and high-performance liquid chromatography (HPLC) using the 7500 and LC 1200 devices (Agilent Technologies, United States) according to the manufacturer's method. Treatment with UDHSS increased productivity and shoot height by 51.1% and 11.3%, respectively. The microelement concentration order in the dry biomass was as follows: Na > K > Ca > S > P > Mg in the control option and Na > K > Ca > Mg > P > S in the UDHSS option, while the microelement export was observed as Fe > Mn > Zn > Ba > B > Cu > Mo and Fe > Mn > B > Zn > Ba > Cu > Mo. In total, the increase was more evident in the microelement accumulation due to a twofold increase in the concentration of iron ions. As for amino acids, L-lysine, L-glycine, L-glutamine, and L-tyrosine became higher. The first three are structural components of biological tissues indirectly indicative of an increase in the fiber strength of the plant culture. [ABSTRACT FROM AUTHOR]

The operator's actions to control a single-bucket excavator when digging a trench for underground pipeline laying are studied. The angular parameters of the working element of a single-bucket excavator are obtained. The time for a full digging cycle and the main elements of the software and hardware complex for collecting and processing data are determined. The dependence of the time of a technological operation on the angular parameter of the working body of the excavator is obtained. [ABSTRACT FROM AUTHOR]

Human respiratory syncytial virus (RSV) is an RNA virus of the family Pneumoviridae and is a common causative agent of acute respiratory infections. Infection with this virus is often severe and can result in fatalities and chronic complications, particularly in high-risk groups such as children under the age of 5 and elderly individuals over 65 years old. This review presents the latest data on the taxonomy, virion structure, and genome map of RSV, as well as its role in the etiology of acute respiratory diseases. We have analyzed over 100 publications on RSV genotyping in different parts of the world including Russia published between 2015 and 2023. The genetic composition of RSV isolates in Russia is similar to that in other regions of the world, which are predominantly represented by genotypes ON1 and BA9. The development of effective vaccines is crucial for successful disease control. The review summarizes global advances in the development of interventions against RSV, emphasizing promising treatments currently undergoing clinical trials and the ones that have recently been approved. Similar interventions (vaccines) are yet to be developed in Russia, but the similarities in genetic composition of RSV in Russia and worldwide offer hope for the rapid development of domestic vaccines against this infection. [ABSTRACT FROM AUTHOR]

The relevance of the engineering and technical solutions implemented at the Branch of Shemyakin–Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences (IBCh RAS), in the 1980s when designing a laboratory building with a vivarium and a nursery of specific pathogen-free (SPF) laboratory animals was discussed. SPF-status laboratory animals are used when performing non-clinical studies according to the OECD principles of Good Laboratory Practice (GLP). [ABSTRACT FROM AUTHOR]

A technique is proposed for reconstructing the electron temperature profile under conditions when the integral absorption coefficient of electron cyclotron emission (ECE) is less than unity. Numerical simulations of plasma ECE were performed for the L-2M stellarator in the ohmic heating regime. It is shown that the radiation temperature profiles recovered from the ECE diagnostics data in the ohmic heating regime require considerable correction. The profile width turns out to be smaller than the width of the true temperature profile, and the on-axis plasma temperature is underestimated by ~30%. A new method is proposed for the relative calibration of ECE diagnostics channels in the ohmic heating regime. The resulting calibration coefficients can be used to measure the plasma temperature in the electron cyclotron resonance heating regime. [ABSTRACT FROM AUTHOR]

Impact tests of low-alloy martensitic-bainitic steel AB2 showed that the scale of dynamic deformation and the fracture mechanism change in a threshold manner. The change in the mechanism and scale of fracture is triggered by the resonant excitation of large-scale structural elements of the material (grain conglomerates) due to plastic flow oscillations. In this case, the grain-boundary mechanism of dynamic fracture is replaced by a transcrystalline one. Beyond the strain rate threshold, mesoscopic elementary carriers of dynamic deformation are divided into two groups: low-velocity and high-velocity. Accordingly, the velocity distribution of mesoparticles shows two humps. The velocity spread of mesoparticles sharply increases under these conditions, while the mass velocity defect (change in the shock wave amplitude) becomes negative. The latter fact indicates the local acceleration of mesoparticles in discrete regions of the target (the so-called shooting of mesoparticles in the shock wave direction). Transcrystalline cracks are randomly distributed throughout the specimen and have a random orientation. [ABSTRACT FROM AUTHOR]

Information concerning the allometric growth of the bivalve mollusk (Mya arenaria) populations in the intertidal zones of Zelenetskaya and Yarnyshnaya inlets, Barents Sea, is presented. The population density in Zelenetskaya Inlet averages 40 ind./m2 and the biomass is 280 g/m2 versus 62.6 ind./m2 and 142 g/m2 in Yarnyshnaya Inlet, respectively. A detailed analysis of the granulometric composition of bottom sediments of the intertidal zone and the content of organic matter are determined for the first time. The study areas are found to differ in the composition of bottom sediments. The organic matter in Zelenetskaya Inlet averages 0.8% versus 2.2% in Yarnyshnaya Inlet. Shell formation is determined by adaptations to living conditions, also reflecting the different size and age structure of M. arenaria populations. Among the mollusks of older age groups, the shell grows allometrically, following the principle of weak negative allometry versus isometrically among young individuals. [ABSTRACT FROM AUTHOR]

Differentiation of induced pluripotent stem cells (iPSCs) from patients and healthy donors allows in vitro study of genetic disorders. The authors have previously reported a clinical case of recurrent pregnancy loss in a patient with skewed X-chromosome inactivation in peripheral blood lymphocytes, endometrium, and buccal epithelium. A 239 kb microdeletion at Xq24 that affected eight genes, including UBE2A, has been found. In this work, an iPSC line iTAF15Xsk4 was produced from the patient's skin fibroblasts using nonintegrating episomal vectors. The iPSC line had a normal karyotype, expressed pluripotency markers, and expressed markers of all three germ layers upon differentiation in embryoid bodies. This cell line could be used for the UBE2A deficiency syndrome study. [ABSTRACT FROM AUTHOR]

For the first time, a fully neural approach has been proposed, capable of solving the optimization problem of routes of extremely large dimensions (~5000 points) with real-world constraints such as cargo capacity, time windows, and delivery sequencing. The proposed solution allows for rapid suboptimal problem solving for small and medium dimensions (<1000 points). Meanwhile, it outperforms heuristic approaches for tasks of extremely large dimensions (>1000 points), thereby representing a state-of-the-art (SotA) solution in the field of route optimization with real-world constraints and extremely large dimensions. [ABSTRACT FROM AUTHOR]

We consider the population of point X-ray sources from the two-year SRG/eROSITA survey in the 1 DESI spectroscopic survey region in the eastern Galactic hemisphere (eROSITA–1 DESI–East). The data under consideration combine a large survey area (compared to the medium-format Stripe82X and XMM-XXL X-ray surveys) and a record high completeness of spectroscopy for the optical counterparts of X-ray sources. We compare the results of the photometric (SRGz) and spectroscopic/astrometric (DESI EDR, SDSS, HELP, GAIA) measurements of the classes and redshifts of objects in three X-ray-flux-limited eROSITA–1 DESI–East samples: erg s cm (bright), erg s cm (medium), and erg s cm (faint) with a total area of 91.4, 91.4, and 16.62 deg , respectively. We propose a new method of postprocessing the probabilistic photo-z predictions based on a two-temperature correction of the probability density function . This approach allows the calibration of the probabilistic predictions and confidence intervals of the photometric redshifts for eROSITA X-ray sources obtained by SRGz to be improved significantly. [ABSTRACT FROM AUTHOR]

We present the results of the optical identification and spectroscopic redshift measurements of 216 galaxy clusters detected in the SRG/eROSITA all-sky X-ray survey. The spectroscopic observations were performed in 2020–2023 with the 6-m BTA telescope at the Special Astrophysical Observatory of the Russian Academy of Sciences, the 2.5-m telescope at the Caucasus Mountain Observatory of the Sternberg Astronomical Institute of the Moscow State University, the 1.6-m AZT-33IK telescope at the Sayan Solar Observatory of the Institute of Solar–Terrestrial Physics of the Siberian Branch of the Russian Academy of Sciences, and the 1.5-m Russian–Turkish telescope (RTT-150) at the TÜBİTAK Observatory. For all of the galaxy clusters presented here the spectroscopic redshift measurements have been obtained for the first time. Of these, 139 galaxy clusters have been detected for the first time in the SRG/eROSITA survey and 22 galaxy clusters are at redshifts , including three at . Deep direct images with the rizJK filters have also been obtained for four distant galaxy clusters at . For these observations we chose the most massive clusters and, therefore, most of the galaxy clusters presented here with the spectroscopic redshifts measured by us will most likely enter in future into the cosmological samples of galaxy clusters from the SRG/eROSITA survey. [ABSTRACT FROM AUTHOR]

The problem of ice accretion modeling of a streamlined body surface is critical for ensuring flight safety in conditions of ice formation. The formation of ice growths on the bearing parts and elements of the power systems of aircraft can significantly affect the flight characteristics. The process of ice formation itself is complex. To obtain a qualitative picture of the ice buildup profile, it is necessary to take into account many physical processes, including gas dynamics, thermal conductivity, the dynamics of drops falling to the surface, and the flow of liquid over the surface. The calculation of the ice cover must be performed iteratively, since the resulting ice significantly affects the gas-dynamic characteristics, which must be recalculated with ice growth. An important part of modeling is the evolution of the ice surface in the process of ice formation. This article discusses various approaches to modeling the evolution of a surface and proposes a new algorithm for constructing a new surface using a common envelope for family of spheres whose centers are located on the original surface. In the process of evolution, various artifacts and anomalies may arise on the surface, due to which further calculations may become impossible. To eliminate these obstacles, the article considers methods for adapting the computational mesh in the process of evolution, as well as eliminating potential self-intersections that impede further calculations. [ABSTRACT FROM AUTHOR]

2D and 3D simulations of the penetration of neutral particles into the plasma with parameters corresponding to the ohmic heating regime in the L-2M stellarator were performed, and the simulation results were compared. Radial distributions of neutrals density in plasma and model energy spectra of fluxes of charge-exchange atoms escaping from the plasma were obtained. For the conditions of the ohmic heating regime in the L-2M stellarator, the limiting plasma densities were determined, above which it is necessary to take into account the recombination processes when performing simulations. Comparison of the model energy spectra of fluxes of charge-exchange atoms escaping from the plasma with experimental data made it possible to construct the radial distributions of the neutrals density in absolute units. In this case, the calculated density of neutrals at the plasma axis turned out to be ~1015 m–3, which is four orders of magnitude less than the density of charged particles 1019 m–3. [ABSTRACT FROM AUTHOR]

The paper discusses the development of a technological scheme for the comprehensive processing of copper cable conductors with a contact surface coating containing lead. A hydrometallurgical method for removing (leaching) lead from the surface of copper conductors of the cable scrap by using solutions consisting of a mixture of acetic acid and hydrogen peroxide at various process parameters has been investigated. The optimization of the controlled parameters of the process was performed. It has been established that the highest rates of the lead dissolution process are achieved at a ratio of CH3COOH:H2O2 = 2:1. An equation is proposed to describe the dependence of the lead dissolution process on the controlled parameters, such as duration of sample processing, solution temperature, and pH level. The kinetics of lead dissolution in the mixture of acetic acid and hydrogen peroxide has been studied. The equation describing the lead dissolution process at an atmospheric pressure and temperature range of 20–96°C is obtained. A modernized technological scheme for cable scrap processing has been developed and proposed. The scheme includes process operations related to mechanical separation and sorting of the raw materials with subsequent hydro- and electrometallurgical treatment of the resulting product. Moreover, each material recovered according to the proposed scheme represents a finished commercial product. [ABSTRACT FROM AUTHOR]

We report the results of optical spectroscopy of eight highly variable X-ray sources—AGN candidates from all-sky survey of the eROSITA telescope of the Spectrum-Roentgen-Gamma Space Observatory—performed with the TDS spectrograph (3600–7500 Å, ) attached to the 2.5-m telescope of the Caucasian Mountain Observatory of Sternberg Astronomical Institute of M.V. Lomonosov Moscow State University. We determined the redshifts of the sources from the emission and absorption lines in their spectra. At least five objects can be classified as Seyfert galaxies. We performed pilot infrared photometry of three distant quasars with using the ASTRONIRCAM camera and show that on the " " diagram the distant quasars studied can be confidently distinguished from Galactic red and brown dwarfs. This result proves the possibility of preliminary classification of distant X-ray quasar candidates by their IR colors for further detailed spectroscopic study on large telescopes. [ABSTRACT FROM AUTHOR]

Designs of navigation group radio-optical reflectors of circular action have been developed. The results of experimental studies of their scattering characteristics as part of a floating buoy are presented. Comparative estimates of the visibility range of floating buoys equipped with group radio-optical reflectors in the optical and radar wavelength ranges are obtained. Experimental studies were carried out in the Ob basin of inland waterways, on the Ob and Tom rivers. [ABSTRACT FROM AUTHOR]

We discuss an algorithm whereby the massive galaxy clusters detected in the SRG/eROSITA all-sky survey are identified and their photometric redshifts are estimated. For this purpose, we use photometric redshift estimates for galaxies and WISE forced photometry. To estimate the algorithm operation quality, we used a sample of 634 massive galaxy clusters from the Planck survey with known spectroscopic redshifts in the range . The accuracy of the photometric redshift estimates for this sample is , the fraction of large deviations is 1.3 . We show that these large deviations arise mainly from the projections of galaxy clusters or other large-scale structures at different redshifts in the X-ray source field. Measuring the infrared (IR) luminosities of galaxy clusters allows one to estimate the reliability of the optical identification of the clusters detected in the SRG/eROSITA survey and to obtain an additional independent measurement of their total gravitational masses, . We show that the masses of the galaxy clusters estimated from their IR luminosity measurements have an accuracy , comparable to the accuracy of the mass estimation for the galaxy clusters from their X-ray luminosities. [ABSTRACT FROM AUTHOR]

We describe the methods of the SRGz system for the physical identification of eROSITA point X-ray sources from photometric data in the DESI Legacy Imaging Surveys footprint. We consider the models included in the SRGz system (version 2.1) that have allowed us to obtain accurate measurements of the cosmological redshift and class of an X-ray object (quasar/galaxy/star) from multiwavelength photometric sky surveys (DESI LIS, SDSS, Pan-STARRS, WISE, eROSITA) for 87 of the entire eastern extragalactic region ( , ). An important feature of the SRGz system is that its data handling model (identification, classification, photo-z algorithms) is based entirely on heuristic machine learning approaches. For a standard choice of SRGz parameters the optical counterpart identification completeness (recall) in the DESI LIS footprint is (with an optical counterpart selection precision of ); the classification completeness (recall) of X-ray sources without optical counterparts in DESI LIS is ( precision). A high quality of the photometric classification of X-ray source optical counterparts is achieved in SRGz: photometric classification completeness (recall) for extragalactic objects (a quasar or a galaxy) and stars on a test sample of sources with SDSS spectra and GAIA astrometric stars. We present an analysis of the importance of various photometric features for the optical identification and classification of eROSITA X-ray sources. We have shown that the infrared (IR) magnitude , the X-ray/optical(IR) ratios, the optical colors (for example, ), and the IR color () as well as the color distances introduced by us play a significant role in separating the classes of X-ray objects. We use the most important photometric features to interpret the SRGz predictions in this paper. The accuracy of the SRGz photometric redshifts (from DESI LIS, SDSS, Pan-STARRS, and WISE photometric data) has been tested in the Stripe82X field on a sample of 3/4 of the optical counterparts of eROSITA point X-ray sources (for which spectroscopic measurements are available in Stripe82X): (the normalized median absolute deviation of the prediction) and (the fraction of catastrophic outliers). The presented photo-z results for eROSITA X-ray sources in the Stripe82X field are more than a factor of 2 better in both metrics ( and ) than the photo-z results of other groups published in the Stripe82X catalog. [ABSTRACT FROM AUTHOR]

Recycled scrap and waste are used in the production of copper and copper alloys. Cable scrap containing impurities of non-ferrous and ferrous metals is often used as copper scrap. Herein, we propose a novel steam-air oxidation method for the purification of copper alloys. In this method, the melt surface was blown with a steam-air mixture supplied to the melting furnace using a specially manufactured device. Technological parameters ensuring the effective removal of iron, tin, lead, and zinc impurities from the copper melt were determined experimentally. The melt oxidation degree, oxidizer consumption, and duration of the transition of impurities into slag and the gas phase were found to be the key parameters affecting the remelting refining of copper scrap. The technological parameters for the oxidation refining of the melt were optimized using the evolutionary solution search method in order to improve the efficiency of the process and reduce the deoxidizer consumption. It was found that to achieve the maximum efficiency of copper refining, it is necessary to ensure the optimal steam-air oxidation of the melt with oxygen dissolved in it. The results demonstrated the applicability of steam-air oxidation in the refining of copper scrap containing more than 1.6% impurities (including iron, tin, lead, and zinc) to obtain copper melts with chemical compositions corresponding to grades M0 and M1. [ABSTRACT FROM AUTHOR]

The vehicle routing problem with pickup and delivery is one of the most important problems in the context of global urban population growth. Although these kinds of small-size problems can be solved using various classical approaches, a fast (or real-time) route optimizer under real-world constraints (such as throughput and time window constraints) for medium- and large-size problems is still a challenge. In this work, we first successfully applied a deep reinforcement learning approach (a modified JAMPR model) to solve the capacitated pickup and delivery problem with time windows (CPDPTW). We obtained a robust model that gives a fast optimal solution for small- to medium-size problems and gives a fast suboptimal solution for large-size (>200) problems. [ABSTRACT FROM AUTHOR]

We present the results of our search for massive galaxy clusters among extended X-ray sources from the SRG/eROSITA survey using data from the Planck survey and data from optical and infrared sky surveys. Optical observations of these clusters are carried out with the 6-m telescope at the Special Astrophysical Observatory of the Russian Academy of Sciences (BTA), the 2.5-m telescope at the Caucasus Mountain Observatory of the Sternberg Astronomical Institute of the Moscow State University (AZT-33IK), and the 1.5-m Russian–Turkish telescope (RTT-150). We provide data on the optical identifications and spectroscopic redshift measurements for 11 massive galaxy clusters with masses higher than located at redshifts – . Such clusters are very rare objects; most of the clusters with such a high mass in the observable Universe have already been detected previously by the Sunyaev–Zeldovich effect in the Planck all-sky survey. Being anomalous, they can be sensitive indicators of possible deviations of the cosmology from the standard model with a quasi-flat spectrum of initial Gaussian perturbations. [ABSTRACT FROM AUTHOR]

The properties are analyzed of plasma confinement in the L-2M stellarator immediately after switching off the ECR heating pulse. For this stage of plasma confinement, the experimental dependence was obtained of the total power loss on the plasma energy content, which characterizes the properties of the self-consistent state of plasma in the L-2M stellarator and plasma confinement in the magnetic system of this facility. The scaling law was obtained for the energy lifetime in the L-2M stellarator in the stage after switching off the ECR heating pulse. It was shown that this scaling law is very close to the scaling law for the L-2M stellarator in the quasi-stationary stage of the discharge. [ABSTRACT FROM AUTHOR]

The first experiments were performed at the L-2M stellarator on testing the quadrupole antenna in the regime of electron cyclotron resonance plasma heating. Test measurements of the antenna radiation resistance showed that the new antenna excites both fast and slow magnetosonic waves in plasma. The ra-diation resistance of the antenna was measured, and studied as a function of the energy content and plasma density. [ABSTRACT FROM AUTHOR]

A quadrupole antenna has been designed and produced at the L-2M stellarator for experiments on ion cyclotron plasma heating and current drive. Using a power meter of the incident and reflected waves, the first measurements of the radiation resistance of the antenna have been performed in the ohmic heating regime. The radiation resistance of the antenna has been measured as a function of the mean plasma density. It is shown that the fraction of absorbed power ensured by the coaxial modes is 25%. The created quadrupole antenna can also be used for current drive. The proposed method is based on the conversion of fast magnetosonic waves to slow magnetosonic waves with their subsequent absorption by plasma electrons, which is accompanied by current drive processes. [ABSTRACT FROM AUTHOR]

We present an extended catalog of Sunyaev–Zeldovich (SZ) sources from Planck data based on a combination of the samples obtained by two independent approaches to the detection of objects in microwave data: the segmentation of sources by a deep learning (U-net) model on the intensity maps in the 100–850 GHz HFI channels is supplemented by the search for SZ sources on the prepared (NILC) Compton -parameter maps. By comparing our sample of Planck SZ objects with the most complete catalogs of galaxy clusters obtained from microwave (PSZ2, ACT) and X-ray (the preliminary 1-year SRG/eROSITA catalog of clusters in the eastern Galactic sky; MCXC from ROSAT observations) sky surveys, we have analyzed the galaxy cluster mass (), redshift (), and X-ray flux () selection functions. We see two scenarios for using our extended catalogs of SZ sources from Planck data: (i) the sample of only reliable SZ objects from the catalog of candidates can be used directly, for example, to search for unique objects in it or to investigate the population of clusters and (ii) the entire catalog of SZ objects contains a considerable number of spurious sources, but, at the same time, has almost all of the possible detected galaxy clusters in the Planck data (it can be used in combination with other catalogs of candidates for galaxy clusters obtained independently from data in other ranges or with other instruments). [ABSTRACT FROM AUTHOR]

We present the results of the optical identification, classification, and analysis of our photometric and spectroscopic observations of the X-ray transient SRGe J214919.3+673634 discovered by the eROSITA telescope onboard the Spectrum–Roentgen–Gamma orbital observatory in the summer of 2021 during the fourth sky survey. The photometric observations of the optical counterpart of SRGe J214919.3+673634 performed at the 6-m BTA telescope of SAO RAS, the 1.5-m Russian–Turkish telescope RTT-150, and the 2.5-m telescope of CMO SAI MSU as well the archival data from the 48-inch ZTF telescope have shown that the source is a cataclysmic variable with an orbital period min and exhibits a long-term photometric variability from (low state) to (high state). We show that the light curves in the high state are consistent with the model of an accreting magnetized white dwarf and suggest that SRGe J214919.3+673634 belongs to the AM Her variables. The spectra of the optical counterpart taken in the low state at BTA are consistent with the spectral energy distribution of a white dwarf with a temperature K. [ABSTRACT FROM AUTHOR]

We consider the architectures of convolutional neural networks used to assess the emotional state of a person by their speech. The problem of increasing the efficiency of emotion recognition by reducing the computational complexity of this process is solved. To this end, we propose a method transforming the input data into a form suitable for machine learning algorithms. [ABSTRACT FROM AUTHOR]

The paper presents the simulation results of the mode propagation parameters in a circular waveguide consisting of two layers of right- and left-handed materials (Veselago media). The model tests allow to conclude that there are many magnetic modes with a significant deceleration of the phase velocity. [ABSTRACT FROM AUTHOR]

We present a probabilistic model built for the optical cross-match between the SRG/eROSITA X-ray sources and photometric data from the DESI Legacy Imaging Surveys. The model relies both on positional and photometric information on optical objects nearby X-ray sources and allows performing selection with precision and recall (for erg s cm ). With this model, we calibrated positional error of the SRG/eROSITA sources detected in the Lockman Hole: . The model will become a part of the SRGz system for data analysis of the X-ray data obtained from the all-sky SRG/eROSITA survey. [ABSTRACT FROM AUTHOR]

We discuss the results of our spectroscopy for 17 candidates for distant quasars selected by the SRGz classification system based on data from the first and second sky surveys with the eROSITA telescope onboard the SRG X-ray observatory. Most of the quasar candidates were selected within the DaLeQo observing program, whose goal is a search for the most X-ray luminous quasars with luminosities erg s at redshifts . Our spectroscopic observations were carried out at the 6-m BTA telescope with the SCORPIO-2 spectrograph. We have managed to confirm eight new X-ray quasars at , including the quasar SRGe J020142.8-015347 at . Owing to the large diameter of the BTA mirror and the high quantum efficiency of the SCORPIO-2 spectrograph in the range 6000–9000 Å, we have managed to measure the С IV (1549 Å) line parameters and to estimate the supermassive black hole masses and accretion rates for seven quasars. [ABSTRACT FROM AUTHOR]

Methods for increasing energy efficiency in the electrical-power-supply systems of arc plasma treatment facilities, as well as general characteristics characteristic of the arc process that affect electric-power quality, are considered. The structure and general principle of operation of an experimental electric-arc unit are described. Data on changes in such characteristics as active, reactive, and full power; total harmonic voltage and current distortion; and voltage deviation, as well as the level of higher-harmonic current distortion, are systematized and analyzed. Each of the experimental unit characteristics depending on the arc operating current are established on an empirical level. The main relationships are presented by means of which, based on empirical dependences, an energy-efficient unit-control system could determine the active energy loss in the power-supply lines of the unit originating from decreasing electric-power quality. [ABSTRACT FROM AUTHOR]

Explosion chamber modification is proposed. It is intended for studying detonation and shock-wave processes using synchrotron radiation. Examples of explosive chamber designs that meet the necessary conditions are given. Numerical simulation is used to obtain a dependence between the degree of inhomogeneity of the stress state of an explosion chamber shell and the ratio of the shell radius to its thickness. [ABSTRACT FROM AUTHOR]

The paper investigates the effects of an additional mesoporous structure on the physicochemical, textural, and catalytic properties of a Mo/HZSM-5 catalyst for methane dehydroaromatization. The mesoporous structure was generated by adding carbon black P354 during the synthesis of a ZSM-5 zeolite; this carbon was removed during the subsequent calcination of the sample. The catalyst consisted of 0.5–1.0 mm pellets that were prepared by molding a zeolite powder into tablets followed by their grinding and sifting through sieves. The paper describes the results of an investigation into the methane dehydroaromatization kinetics, as well as relevant data obtained by X-ray fluorescence, IR spectroscopy, X-ray diffraction, low-temperature nitrogen adsorption, transmission electron microscopy, and X-ray photoelectron spectroscopy. The addition of carbon black during the zeolite synthesis was demonstrated to improve the catalytic activity, with respect to aromatic production, and performance stability in non-oxidative methane conversion. [ABSTRACT FROM AUTHOR]

Based on observations with the transient double-beam spectrograph (TDS) at the 2.5-m telescope of the Caucasus Mountain Observatory of SAI MSU, we have determined the redshifts for 15 new quasars detected in X-rays by the eROSITA telescope of the SRG orbital observatory during the first three all-sky surveys. The redshifts of the sources lie in the range 0.5–4.156. We have estimated the masses of the central supermassive black holes and the bolometric luminosities for eight quasars from the width of the C IV 1549 Å emission line and the continuum flux at 1350 Å. For these objects we have also estimated the ratio of the X-ray luminosity to the Eddington limit to be a few percent. At the same time, the bolometric-to-Eddington luminosity ratio for them has turned out to be in a fairly narrow range, 30–40 . A large ratio points to an active growth of the mass of the central black holes in these objects. [ABSTRACT FROM AUTHOR]

This paper presents the results of experiments on the methane-hydrogen mixture combustion in a test bench model of a dual-mode wide-range ramjet combustion chamber with a variable geometry flow path, obtained as part of a work under the LEA program. [ABSTRACT FROM AUTHOR]

An attempt to detect the soft X-ray pit (SXR-pit) phenomenon at the L-2M stellarator has been made in different plasma heating regimes using direct spectral measurements. The abnormally strong absorption of soft X-ray plasma radiation in its passing through beryllium foils with thicknesses of 90 μm or more is called the SXR-pit phenomenon; it has been observed at the T-11M tokamak and a number of other tokamaks. A scanning spectrometer and multichord diagnostics of soft X-rays were used in the experiment. It is shown that the SXR-pit phenomenon was not observed at the L-2M stellarator with the plasma parameters similar to those at the T-11M tokamak either in the ohmic heating regime or in the regime of electron-cyclotron-resonance plasma heating. [ABSTRACT FROM AUTHOR]

The results of multiwavelength observations of the very massive galaxy cluster SRGe CL2305.2–2248 detected in X-rays during the first SRG/eROSITA all-sky survey are discussed. This galaxy cluster has also been detected previously in the millimeter band in the South Pole Telescope (SPT-CL J2305–2248) and Atacama Cosmology Telescope (ACT-CL J2305.1–2248) surveys through the observation of the Sunyaev–Zeldovich effect. The spectroscopic redshift has been measured at the 6-m BTA telescope, . In addition, deep photometric measurements of galaxies have been performed at the Russian–Turkish 1.5-m telescope (RTT-150). The mass of the cluster is estimated from the eROSITA data to be . We show that this cluster is among several tens of the most massive clusters in the observable Universe and among only a few most massive galaxy clusters at . [ABSTRACT FROM AUTHOR]

The electron temperature profiles and the pressure profiles of the plasma electron component are analyzed in the ECRH regime at the L-2M stellarator. It is shown that at low ECRH powers (PECRH <250 kW), the electron temperature profiles have the same shape. At higher heating powers, the shape of the temperature profiles changes. They became flat in the core region of the plasma column. It is also shown that at low ECRH powers (PECRH < 250 kW), the pressure profiles of the plasma electron component have the shape that can be approximated by the canonical pressure profile for stellarators, that is, they are self-consistent. At ECRH powers higher than 250 kW, it is impossible to unambiguously conclude whether the pressure profiles at the L-2M stellarator are self-consistent. [ABSTRACT FROM AUTHOR]

Structural equation modeling (SEM) is a technique for analysis of linear relations represented as the causal and correlational relationships between observed and latent variables. SEM is a popular tool in a wide range of fields, from the humanities to the natural sciences. Over the past decade, this method has become especially interesting in areas that are at the interface with biology. However, the common assumption that observations are independent is often violated in biological data, which should be taken into account when constructing a mathematical model. In addition, in genome-wide association studies, the time of optimization of model parameters is a critical factor. In this paper, we propose a new SEM model, as well as a fast way to estimate its parameters. [ABSTRACT FROM AUTHOR]

Results of the spectroscopic observations at the 1.5-m Russian–Turkish telescope for another group of 12 X-ray sources discovered by the eROSITA telescope onboard the SRG space observatory and identified by the SRGz machine learning system as candidates for distant X-ray quasars are presented. Ten objects have been confirmed as quasars at redshifts and two sources have turned out to be active galactic nuclei (AGNs) at and . [ABSTRACT FROM AUTHOR]

The electron energy distribution functions that form in the plasma heating region were recovered from data on the soft X-ray spectra in the energy range of 2−20 keV. The spectra were measured at the L-2M stellarator in the regime of electron cyclotron resonance (ECR) heating in two experiments: on the axial ECR heating (the heating power was PECRH = 250 kW, the electron density was ne = 1.9 × 1019 m–3, and the electron temperature was Te = 0.74 keV) and the off-axial ECR heating (PECRH = 350 kW, ne = 2.5 × 1019 m–3, and Te = 0.7 keV). It was shown that in both experiments the electron energy distribution functions are not Maxwellian and that considerable ensembles of suprathermal electrons form in the heating regions. [ABSTRACT FROM AUTHOR]

During the first all-sky survey of the SRG orbital observatory, the X-ray source SRGE J170245.3+130104 was discovered with the eROSITA telescope on March 13–15, 2020. Its optical counterpart was identified by photometric attributes as a candidate for distant quasars at . The spectroscopic observations of the object carried out in August and September 2020 at the 6-m BTA telescope with the SCORPIO-II instrument confirmed that SRGE J170245.3+130104 is a quasar at redshift . According to the eROSITA data obtained during the first sky survey, the X-ray luminosity of the quasar is erg s in the 2–10 keV energy band, while its X-ray spectrum can be approximately fitted by a power law with a slope . The quasar was detected again with the eROSITA telescope half a year later (on September 13–14, 2020) during the second sky survey, with its X-ray luminosity, probably, having decreased approximately by a factor of 2 at a confidence level . SRGE J170245.3+130104 has turned out to be the most X-ray luminous quasar among all of the known quasars at redshifts . At the same time, it is also one of the radio loudest distant quasars (radio loudness ), which may imply that this is a blazar. We present a catalog of all the quasars at detected in X-rays to date. [ABSTRACT FROM AUTHOR]

The effect of the induced longitudinal (along the toroidal magnetic field) electric field on the shape of soft X-ray spectra in the regime of electron cyclotron resonance (ECR) heating of plasma in the L-2M stellarator is considered. Causes of the appearance of non-Maxwellian two-slope spectra of soft X-rays measured in the axial ECR plasma heating regimes at the introduced microwave powers of 200–400 kW are analyzed. In the authors' opinion, the two-temperature spectral shape arises due to the fact that radiation coming from two plasma regions falls in the field of view of the spectrometer when measuring the spectra along the central chord. A radiation fraction comes from the axial plasma region; another fraction comes from the heating region which in the high-power ECRH regime is approximately at half the plasma radius, rather than at the plasma center. [ABSTRACT FROM AUTHOR]

The shape is analyzed of the electron temperature profiles measured in experiments on the axial ECR heating at the L-2M stellarator at different densities and heating powers. It is ascertained that when the reduced ECR heating power exceeds some threshold value, the electron temperature profiles become broadened and flat in the core region of the plasma column. The correlation is revealed between the appearances of the flat temperature profiles and the density profiles with a dip in the axial region (the dip-shaped profiles) occurring as a result of the density pump-out effect. It is concluded that the appearance of the dip-shaped density profiles in the plasma results in a change in the mechanism of microwave radiation absorption. Hypothetically, the cyclotron absorption of the electron Bernstein waves becomes the dominant mechanism for the microwave radiation absorption that, in turn, results in the formation of the broad and flat (in the core region) electron temperature profiles. [ABSTRACT FROM AUTHOR]

A method for determining the longitudinal electric field from the spectrum of soft X-ray radiation is used to measure the radial distribution of the longitudinal electric field. In the ohmic heating regime, statistically reliable spectra of soft X-ray radiation were measured at the L-2M stellarator. It was obtained that the longitudinal field is distributed approximately uniformly over the radius. Comparison of the measured soft X‑ray radiation (SXR) spectra with the model bremsstrahlung spectrum of magnetized plasma in the longitudinal electric field has shown that at energies W > 3 keV, the measured spectrum deviates markedly not only from the Maxwellian one but also from the model spectrum of magnetized plasma in an electric field. Using SXR spectra that were measured in the regime of electron cyclotron resonance (ECR) plasma heating (without the ohmic-heating current), estimates are made of the longitudinal electric field that may occur in plasma due to drag currents, which are created during ECR heating. The dependence of the electric field on the plasma density was measured and it was shown that it agrees with the dependence of the difference current flowing through the plasma on the density. [ABSTRACT FROM AUTHOR]

Results of the first spectroscopic observations at the 1.5-m Russian–Turkish telescope for the X-ray sources discovered by the eROSITA telescope onboard the SRG space observatory and identified by the SRGz machine learning system as candidates for distant X-ray quasars are presented. Seven objects have been confirmed as quasars at redshifts and two sources, which were included in the program of optical observations aimed at testing and adjusting SRGz and had a significant uncertainty in the photometric redshift, have turned out to be Seyfert galaxies at . [ABSTRACT FROM AUTHOR]

Experimental and theoretical results demonstrating that the fractal nature of a surface periphery destroyed under the impact of dynamic loading can be attributed to velocity dispersion of particles (elementary deformation carriers) at various scale and structure levels of deformation and fracture are presented. [ABSTRACT FROM AUTHOR]