The purpose of this work was to solve the problem of increasing the wear resistance of car transmission differential parts by implanting them with subsequent treatment by surface plastic deformation.
Methods. To achieve the goal set in the work, the following methods of processing the studied parts were used: correcting the geometry of the spike of a crosspiece that was in use by turning on a rotary-screw machine; applying graphite-tungsten coating to surfaces prepared for implantation and drying it; directly implanting on an installation specially designed for this process; hardening the implanted surface by running in with a two-roller head; fine grinding of the hardened surface of the crosspiece spike; investigation of the wear resistance of hardened surfaces according to the standard methodology; evaluation of the resource of restored and hardened parts.
Results. Based on the conducted studies aimed at increasing the wear resistance of the differential transmission parts of the car, it was found that the properties of the restored and hardened surfaces of the differential crosspiece depend on the composition and structure of the formed surface layer by implanting tungsten-containing materials and subsequent running-in with a two-roller head. In particular, it was found that the wear resistance of the working surfaces of parts repaired and hardened using the new combined technology increases by 2.07 times compared with the new ones with a comparable increase in service life.
Conclusion. Thus, the goal has been achieved, namely, the problem of increasing the wear resistance of the differential transmission parts of the car by implanting them with subsequent treatment by surface plastic deformation has been solved. The results obtained in this work can find practical application in the organization of resource-saving and importsubstituting technologies, which in turn will contribute to the creation of high-tech industries.

Purpose. Optimization the sintering process of an electroerosion charge obtained by the method of electroerosion dispersion of tungsten-free hard alloy waste in an carbon-containing working fluid.
Methods. Tungsten-free carbide waste was selected as the starting material for the study. The dispersion process was carried out in a carbon-containing working fluid—methanol. A setup whose design is protected by Russian Federation Patent No. 2449859 was used for electrical discharge dispersion. The electro-erosion particles were consolidated using the Spark Plasma Sintering system Model 25-10 (SPS 25-10) manufactured by Thermal Technology. The consolidation modes (temperature, pressure, and exposure time) for the new alloy were selected based on the criterion of achieving the maximum microhardness of the sintered samples using the 2³ full factorial experiment method.
Results. The measurements carried out showed that the microhardness of samples sintered by the SPS method from powder dispersed in a methyl alcohol medium is on average 1415 HV.
Conclusion. The determination of optimal parameters of the process of obtaining tungsten-free hard alloy by spark plasma sintering of particles according to the microhardness of sintered samples by conducting a full factor experiment of type 23  has been carried out. The following parameters of the spark plasma sintering unit have been selected as factors: temperature, pressure and holding time. Optimal parameters of the unit operation have been determined for the electroerosion material previously obtained from TFHA waste in carbon-containing medium - distilled water. Based on the results of a series of experiments, the optimal sintering conditions were determined to achieve the maximum microhardness values. The maximum microhardness of the composite with electro-eroded particles obtained in a methanol environment reached 1427 HV, which is 17% higher than that of the base industrial alloy. This maximum was achieved after sintering at 1200 °C under a pressure of 40 MPa with a 5-minute exposure. 

Purpose. This work is focused on a comparative analysis of the chemical structure of two types of materials: metal waste generated when using drilling tools, and a powdered product obtained as a result of electroerosion destruction and dispersion of these wastes.
Methods. As part of the experimental part of the study, metal waste generated during intensive wear of drilling tools without an established marking was used as an object of analysis. The quantitative content of chemical elements and their fractional distribution in the material were determined using a portable Niton Goldd X-ray fluorescence analyzer manufactured in the USA. The measurement procedure was based on irradiating the sample with an X-ray beam, followed by recording the spectral response and interpreting the parameters of the induced fluorescent radiation. When the material was irradiated with X-ray quanta, electromagnetic vibrations were excited in its atomic structure, resulting in secondary radiation. The spectrum of this radiation contained a set of characteristic peaks, individual for the atoms of each chemical element. The elemental composition was identified by the position of these spectral lines, while the mass fraction of the components was determined based on their intensity.
Results. The use of a portable Niton Goldd spectrometer made it possible to establish that the metal waste from the drills belongs to the alloy grade P6M5K5. The results obtained made it possible to uniquely identify the waste under study, intended for subsequent processing using the electroerosion method, which results in the formation of powdery particles of a predominantly spherical shape. The obtained materials have high application potential and can be effectively used in additive manufacturing technologies. A comparative study of the specific content of chemical components in metal waste from drills and the resulting electroerosion powder revealed small changes: an increase in the content of Iron, Cobalt, Nickel and Tin, as well as a decrease in the concentration of Tungsten, Molybdenum, Chromium and Vanadium.
Conclusion. Recycling of metal waste, including waste from high-speed steels, is important for: rational use of resources, reducing dependence on imports, and strengthening the technological sovereignty of the Russian Federation.

Purpose. Determination and study of the composition, structure, and properties of a powdered Cobalt material obtained by electroerosive dispersion of K1Au Cobalt metal waste in a working environment of TS-1 aviation kerosene.
Methods. In order to study the composition, structural features, and characteristics of the cobalt charge, samples of powdered metallic cobalt were obtained. This was achieved through the use of electro-discharge dispersion of K1Au cobalt waste in a carbon-containing working environment. The microstructure of the powder particles was examined using scanning electron microscopy, and the particle size distribution of the charge was assessed using a particle size analyzer. The elemental composition was determined by energy-dispersive X-ray analysis, implemented on the basis of a scanning electron microscope. The phase composition of the charge was determined by a diffractometer using Xray diffraction.
Results. It has been established that the formed fine-grained cobalt powder consists of predominantly spherical and ellipsoidal particles, as well as their agglomerates. No carbon impurities were detected in the powder. Phase analysis showed the presence of a pure Cobalt crystal phase without the formation of carbide compounds. According to the granulometric analysis, the particle sizes are distributed in the range of 0.9 to 63.77 μm, with an average volume diameter of 12.06 μm.
Conclusion. The obtained experimental data create a scientific and practical basis for the development of fundamentally new hard alloys, which may include cobalt powder obtained from metal waste by the method of electro-erosion dispersion. The presented results open up the prospect of further improvement of the composition and regulation of the structure of newly formed alloys. 

The purpose of this work was to conduct X-ray fluorescence analysis of the elemental composition of a sample of metal waste and determine the alloy grade, primarily titanium, planned for processing by electrical discharge dispersion to produce powder suitable for additive manufacturing.
Methods. To determine the elemental composition of a titanium-containing alloy of unknown grade, a metal plate sample measuring 530 mm in length, 144 mm in width, and 4 mm in thickness was collected. Analysis was performed using a Niton XL3t portable X-ray fluorescence spectrometer. Before measurements, the sample surface was cleaned, and each point was analyzed at least three times to enhance reliability. X-ray fluorescence analysis provides rapid and nondestructive determination of the elemental composition of complex materials without the use of reference samples, enabling localized spot analysis with high accuracy and speed (up to 10 seconds), which is especially important when studying potentially heterogeneous objects. The design features of the Niton XL3t instrument enable localized spot analysis of the surface of the test objects, which is crucial when working with materials potentially characterized by structural or chemical heterogeneity. To determine whether the actual chemical composition complies with the regulatory requirements specified in the steel grade list and GOST 19807–91, a comparison was made between the experimentally determined concentrations of elements and the theoretical composition of the alloy.
Results. X-ray fluorescence analysis of the elemental composition of titanium-containing metal waste using a Niton XL3t portable spectrometer reliably established that the sample corresponds to the VT1-2 alloy grade.
Conclusion. The obtained results form the scientific and methodological basis for subsequent research on the processing of these metal wastes using electrical discharge dispersion to produce spherical powders applicable in additive manufacturing. 

Purpose of research. Nanostructuring in magnetron nanofilms of Tantalum nitride by high-frequency magnetron sputtering.
Methods. High–frequency magnetron sputtering on a silicon substrate was carried out depending on the change in the time control parameter t = 1800 - 3600 C. A Tantalum target sprayed at a fixed T = 140°C, P = 300 W, pressure Ar 1.0 Pa was used. The surfaces of the substrates were ion-cleaned for 120 s with a current of 60 mA. The increase in film thickness was achieved by changing the time control parameter t. Nanoscale characterization of the obtained tantalum nitride nanofilms was carried out using atomic force microscopy, digital holographic microscopy, and X-ray phase analysis. Based on the results of statistical AFM image processing, the analysis of autocorrelation functions and changes in fractal dimensions determined by the cube method was performed.
Results. The nanofilm thicknesses were measured and the growth rates of nanofilms were calculated using the precision step method on AFM and CGM images, and their linear increase as a function of time t was proved. According to the XRD data, the formation of the hexagonal hex-Ta2N phase in thin layers and the transition to the dominance of cubic fcc-TaN with increasing thickness have been established. Evolutionary processes of surface morphology were observed with the transition from an isotropic fine-grained structure to a pronounced columnar one, which was confirmed by a decrease in fractal dimension and an increase in the lengths of the autocorrelation function.
Conclusion. In magnetron nanofilms of tantalum nitride deposited by the high-frequency method, a phase transition from the hexagonal hex-Ta2N phase in thin layers to the cubic fcc-TaN phase, starting from a critical thickness, was detected. A decrease in the fractal dimension and an increase in the lengths of the autocorrelation function indicated the evolution of the surface morphology from isotropically fine-grained to pronounced columnar. 

The purpose of this study is to determine the direct contribution of magnetic wave oscillations of magnetization during domain wall motion to the generation of longitudinal acoustic waves and their feedback effect on magnetization reversal processes in yttrium orthoferrite.
Methods. The object of this study is the solution of a system of dynamic equations describing the interaction of magnetic and acoustic subsystems excited by a moving domain wall in yttrium orthoferrite. The equations are solved using perturbation theory, slowly varying amplitude theory, and Lagrangian methods.
Results. For the first time, an explicit solution was obtained for the displacement of a longitudinal acoustic wave generated by a magnetic subsystem accompanying a moving domain wall in yttrium orthoferrite, taking into account the feedback effect of the acoustic wave. Using known values of the parameters included in the system of dynamic equations describing the interactions between the longitudinal acoustic wave and the magnetic subsystem during domain wall motion in yttrium orthoferrite, numerical calculations were performed based on the obtained solution. It is shown that the maximum contribution to a moving domain wall in yttrium orthoferrite due to the feedback effect of a longitudinal acoustic wave reaches about 10-12 m far from the wave velocity and increases by a factor of 104  (to about 10-8 m) at a domain wall velocity close to the wave velocity, i.e., it becomes comparable to its theoretical Landau thickness of ≈ 10-8 m.
Conclusion. An explicit solution is obtained that takes into account the mutual influence of quasiparticle excitations accompanying transonic domain wall motion in yttrium orthoferrite on the interaction mechanisms of the magnetic and acoustic subsystems. This solution allows for meeting modern requirements for memory and logic devices in terms of quality and speed of information processing. Practically significant estimates of the contributions of such interactions are obtained for improving the component base of such devices. 

Purpose. Development of a mathematical model that adequately describes the non-stationary process of cooling long cryogenic pipelines with liquid hydrogen and makes it possible to determine optimal operating parameters that ensure minimal refrigerant consumption in preparation for firing tests of liquid rocket engines.
Methods. A vacuum-insulated pipe made of cryogenic steel with a total length of 272.5 m, with a bore diameter of 96 mm and a wall thickness of 2 mm was used as the modeling object. The total weight of the shut-off equipment located on the main line is 246 kg. Liquid supercooled hydrogen with an inlet temperature of 19 K is supplied to the pipeline under an excess pressure of 0.2 MPa. The ambient temperature is 293 K.
Results. In this paper, we propose a model for cooling long insulated pipelines when liquid water flows through them, which makes it possible to determine the flow parameters at various points in time and estimate the time when the main line enters operating mode. Based on the proposed model, an automated algorithm was developed for calculating the cooling process of a long pipeline with cryogenic components, which makes it possible to obtain data for constructing the temperature fields of the pipeline walls and the flow of transported cryoproducts at various time points, as well as to determine the time when the main line enters operation and the moment of the onset of a stationary single-phase flow. The results of the calculation are in good agreement with the experimental data.
Conclusion. Using this model under various initial and boundary conditions, it is possible to work out the optimal mode of real physical processes and achieve minimal losses of cryogenic components with minimal time spent in preparing bench systems for fire tests, as one of the stages of the production cycle of liquid propellants in mechanical engineering. 

Purpose of research. To study the conditions of separation and determination of mono- and disaccharides in biological samples and food samples by reverse-phase high-performance liquid chromatography with UV detection.
Methods. The studies were carried out using an LC-20AD liquid chromatograph (Shimadzu, Japan) with a spectrophotometric detector, a Supelco LC-18-T column (4.6×250 mm, 5 microns) and LC solution software. An alternative analysis was performed on a KFK-3 spectrophotometer (Russia).
Results. The composition of the mobile phase acetonitrile has been experimentally determined for individual and joint determination of glucose, lactose, sucrose and fructose by high-performance chromatography:water is 80:20 and its flow rate is 0.6 ml/min, at which the highest sensitivity of analyte detection is achieved. Calibration functions for the individual determination of carbohydrates and mixtures are constructed, with the individual determination of glucose, lactose, sucrose and fructose, the linear ranges and detection limits  (с_min) are 0.5–30.0 mg/ml, с_min = 0.15 mg/ml; 25–45 mcg/ml, с_min = 9 mcg/ml; 4–16 mg/ml, с_min = 1.03 mg/ml; 5–40 mg/ml, с_min = 2.35 mg/ml, respectively. When combined: 0.5–15.0 mg/ml, с_min = 0.18 mg/ml for glucose; 30–45 mcg/ml, с_min = 2 mcg/ml for lactose; 4–32 mg/ml, с_min = 2.18 mg/ml for sucrose; 5–30 mg/ml, с_min = 3.34 mg/ml for fructose. The greatest sensitivity was recorded in the determination of lactose. The results of the chromatographic analysis were compared with the data of the spectrophotometric determination of carbohydrates, no significant discrepancies were found.
Conclusion. Analysis of urine and food samples (milk, syrup, and cookies for diabetics) showed compliance with the analyte content stated by the manufacturer and confirmed the diagnosis of the patient who provided the biological fluid. This allows us to recommend the proposed methods for monitoring the content of mono- and disaccharides in samples with complex matrices.