The main trends in the field of improving thermal spraying processes for ceramic coatings formation is, along with enhancement of coating properties, also the reducing the energy consumption for the process. In this regard, one of the important directions for improving these technologies with plasma is the development of their new versions, using the principle of adding inexpensive fuel-oxidizing mixtures based on hydrocarbons (natural gas, liquefied gas) with air. This type of plasma-fuel type of spraying will be promising for application at the present time, first of all, in order to obtain refractory functional coatings. For this purpose, the opportunity for upgrading an industrial unit/system for plasma spraying of powder materials with arc plasma torch of 25–40 kW power was investigated with the use of experimental variant of a fuel gas-vortex intensifier. Herewith the thermal engineering assessment for possible parameters of the generated high-temperature flow from the torch with this intensifier was carried out to compare these with established thermodynamic characteristics on the applicability range of this system for optimization of the oxide and carbide coating spraying process (using the examples of Al₂O₃, Cr₃C₂ and other powders); and gas dynamic and heat transfer calculations of the intensifier operating regimes in this model unit was also performed. New regimes, which were analyzed in our research as the simulants of Al₂O₃ spraying, have the advantage over the N₂-plasma regimes from the point of view of such kinetic parameter of powder processing as ability of heating factor of hot gas medium. Taking into account the calculated data, the experimental system was developed based on the standard spraying unit UPU-3D with a fuel intensifier of the selected design and the preliminary testing of its operation was carried out at the power of 30±2 kW under the following combination of gases in the torch: nitrogen and mixture of liquefied petroleum gas with air. This system has shown the stable operation in certain range of parameters and, according to the zonal calorimetrical measurement and photo-registration of jets, it provides 30–35 % more energy emission from torch generated jet (with attached fuel vortex chamber) in atmospheric conditions, in a comparison with the torch regime with pure N₂-plasma with the same power on the arc of plasma heater. Use of the system creates an opportunity to spray carbide powders as well as oxide ones at improved intensity of coating producing in a comparison with standard regimes of commercial spraying units with N₂ or Ar plasmas.

The possibility of using dynamic indentation method for measurement the elastic and strength properties of polymer products obtained by additive synthesis using the SLA-technology is considered. The sensitivity of the method to changes in hardness, tensile strength, and elastic modulus of products obtained by different printing modes with a thickness of the cured layer of photopolymer resin of 100, 50, and 25 microns has been estimated. A comparison is made of two main methods for calculating the physical and mechanical characteristics of a material according to the data of its impact loading diagram: an adapted classical method of mechanics of contact interaction, considering the geometric parameters of the deformed region of the material, and a method based on the energy characteristics of shock interaction. It was found that the highest sensitivity of the dynamic indentation method to changes in the properties of the additive polymer, depending on the thickness of its hardened layer, is provided when using an energy computational model for evaluating the properties of the material. The results obtained are the basis for the methods of non-destructive testing of polymer products of additive manufacturing by the method of dynamic indentation. The implementation of these techniques in portable measuring equipment is an alternative to standard destructive tests and will allow obtaining reliable data on the properties of the controlled material without the need to manufacture special witness samples.

The paper presents the results of studies of the effect of heat treatment regimes on changes in the structure and properties of steel-copper alloy pseudo-alloys obtained by infiltration. It is shown that, depending on the composition and initial density of the steel skeleton, the strength of the material increases by 1.3–1.8 times, the hardening effect is realized when the carbon content in the steel skeleton is 0.3–1.5 % and is achieved due to changes in the structure and phase composition of the steel base and copper phase. It has been established that during heating for quenching and during tempering, redistribution of carbon occurs in the iron phase, which is more pronounced in the frame of the pseudo-alloy made of medium-carbon steel. The formation of a “crust” structure in the grains of the skeleton is noted, while in the skeleton made of medium-carbon steel this occurs at a tempering temperature of 200 °C, in low-carbon steel – at a temperature of 500–650 °C. In a high-carbon steel skeleton, carbon stratification in the grain body is less pronounced. An increase in the strength of pseudo-alloys at tempering temperatures of 500–650 °C is associated with the formation of the α′-phase, the precipitation of the Fe₃C carbide phase and the metastable Fe₂C phase in the iron phase, as well as the precipitation of dispersed phases Fe₄Cu₃, Fe₄Cu₃, η-Cu6Sn5 and δ-Cu₃Sn₈ in the copper phase. Due to the precipitation of phases, the microhardness of the infiltrate in the form of copper in pseudo-alloys after tempering at 550 °C increased from 820–880 to 950–980 MPa, in the form of tin bronze – from 1450 to 1750 MPa. The use of heat treatment leads to an increase not only in the strength, but also in the tribotechnical properties of the pseudo-alloy: the friction coefficient of the pseudo-alloy with a frame of 80 % density made of FeC0.8 steel decreases to 0.008–0.009, the seizure pressure doubles and the wear resistance increases by more than 2.5 times.

The results of experimental studies of the surface roughness parameters of ball bearing treadmills made of steel SHX-15 and the performance of the magnetic abrasive treatment process depending on the properties of the components of the working process medium are presented. The research used methods of mathematical modeling of the technological process of magnetic abrasive processing, subsequent analysis of the obtained multivariate regression equations to identify the most significant technological factors according to the criteria of their interaction and relative influence on surface roughness and processing performance. The relative total contribution to the change in the roughness of the treated surface (Ra, microns) and processing performance (ΔG, mg/min) was established: single control technological factors affect 29,1 % and 48,2 %, respectively; interacting control technological factors 46.8 % and 45.9 %, respectively. The controlling technological factors in descending order of the degree of influence by generalized significance are arranged in the sequence: hydrogen pH, gradient of magnetic induction B (T/mm), microhardness of abrasive HV (GPa), coolant viscosity γ (cSt), processing time t (s) and magnetic permeability µ (mH/m). The interpretation of the physical mechanisms of interaction of controlling technological factors is given. The obtained results of a quantitative assessment of the relative total contribution of single control technological factors can be used in assigning modes of magnetic abrasive treatment of bearing rings, and their interaction – in studies of the synergism of the parameters of the working technological environment, which allows obtaining a much greater effect than using each parameter separately.

In present paper the influence of the boiling surface treatment types of thermosyphon evaporator on the heat transfer coefficient was studied. An experimental setup «Loop thermosyphon with replacing lower part of the evaporator» has been developed and assembled. This feature makes it easy to replace samples with various surface modifications as the lower part of the evaporator. The description of the experimental setup, equipment and research methods is given. Heat transfer coefficients for the samples at various applied thermal loads (from 5 to 200 W) were calculated. In case of flat aluminum plate (boiling surface) concentric grooves and uneven coating of aluminum oxide particles, an increase of the heat transfer coefficient from h₁ = 5760 W/(m²·K) to h₂ = 28339 W/(m²·K) at the supplied heat flux density q = 250 kW/m² was observed. The heat transfer coefficient for a sample without concentric grooves, but with an uneven coating of aluminum oxide particles was h₃ = 16952 W/(m²·K) at q = 250 kW/m². Results of the study can be used for further increase of thermosyphon evaporator efficiency.

The transition from conventional uranium to regenerated fuel, which uses reprocessed spent fuel and enriched natural uranium, improves fuel efficiency and reduces the amount of spent nuclear fuel (SNF). Based on the analysis of published materials concerning mainly the fuel cycles of the VVER-1000 reactor, it was concluded that the most suitable in the conditions of the Republic of Belarus is the use of REMIX fuel. To confirm this conclusion in relation to the VVER-1200 reactors of the Belarusian NPP, computational studies were carried out within the framework of the State program “Scienceintensive technologies and equipment” for 2021–2025, subprogram 3 “Scientific support for the effective and safe operation of the Belarusian nuclear power plant and promising directions for the development of nuclear energy”. The characteristics of a 12-month fuel cycle with multiple recycling (reuse of fuel) according to the REMIX technology with 19.75 % enrichment of added uranium and maintaining the design capacity and duration of the campaign have been obtained. The share of SNF that is not returned to the reactor is 12.8 % (for a cycle with uranium fuel – 100 %); the fraction of waste intended for disposal or long-term storage, respectively, decreases by 8 times, and the specific consumption of natural uranium is reduced from 202 g/(MW·day) for uranium fuel to 159 g/(MW·day) for REMIX fuel. The results obtained can be taken into account when developing a fuel use strategy at the Belarusian NPP.

The most representative accident scenario is determined and a physical and mathematical model is developed for studying the mixing of non-isothermal coolant flows in the structural elements of the V-491 reactor facility (VVER-1200), in which the motion of the medium is described in a three-dimensional non-stationary formulation. Based on the analytical estimates of the list of initiating events, a scenario was chosen with the connection of an idle loop of the main circulation pipeline to three operating ones without a preliminary power reduction. A computational algorithm and a numerical method have been developed for the computational analysis of the selected accident scenario and the justification of the safety of operation of the V-491 reactor facility (VVER-1200). During the numerical simulation, the RANS method was used, which consists in solving the Reynolds-averaged Navier–Stokes equations, the continuity equation and the energy equation. The SST k–ω model of turbulence by Florian Menter is used to close the equations. The verification of the developed physical and mathematical model and calculation procedure was carried out by modeling thermohydraulic processes in models with both a relatively simple geometric design (tee connection) and in a scale model of the reactor vessel (ROCOM experiment), including a lowering section and a pressure mixing chamber. The qualitative agreement of the numerical simulation results with the available data of physical experiments is shown. The results of numerical simulation of the mixing process of non-isothermal coolant flows in the section from the branch pipe of the “cold” thread of the main circulation pipeline to the lower boundary of the fuel of the VVER-1200 core (V-491) are presented. It is shown that the heterogeneity in the temperature distribution at the entrance to the core manifests itself up to 15.5 s of the calculated accident scenario. For calculations the following code coupling were used: Ansys Fluent/Rainbow-TPP.

As a result of the study of a two-dimensional finite element model of the magnetic field of a synchronous electric machine with fractional tooth windings, typical magnetic fluxes (fundamental, edge effect, scattering) in its magnetic system have been identified. The analysis of the degree of influence of magnetic fluxes of the edge effect and scattering on the magnitude of the main magnetic flux is carried out and equivalent circuits of the magnetic circuit of the studied synchronous electric machine with fractional tooth windings are constructed for different positions of the stator teeth relative to the rotor poles. An analytical model has been developed to determine the main magnetic flux through the coil of the working winding of a synchronous electric machine with fractional toothed windings. A feature of the proposed model is taking into account the dependence of the main magnetic flux through the coil of the working winding on the coordinate of the rotor position, the magnetic fluxes of the edge effect and scattering. The developed model allows solving the problem of quantitative determination of the value of the main magnetic flux through the coil of the working winding with high accuracy. In addition, the proposed model makes it possible to determine the influence of the main geometrical parameters of the magnetic circuit on the nature of the change in the main magnetic flux through the coil of the working winding with the least amount of time. The developed analytical model can be applied in the process of optimizing a synchronous electric machine with fractional tooth windings.

The paper describes the principle of measuring linear dimensions using a nano-measuring machine (NMM), which implements the method of measuring three coordinate axes in the range of 25X25X5 mm³. Sources of non-excluded systematic measurement errors are identified, which are conventionally divided into factors associated with the method of measuring length using an interferometer and factors determined by the design and technological features of the nano-measuring machine. Statistical estimates of the measurement result have been determined and the error in transferring the size – meter length in the nanometer range of measurements has been calculated. The results obtained assert that the nano-measuring machine is a unique tool that allows one to carry out measurements of millimeter dimensions with nanometer accuracy. The results obtained can be used for metrological assessment of the step height and step width, when calibrating measuring instruments in the nanometer range, roughness measures in a large range when calibrating profilometers and contourographs, as well as templates and micrometer objects for measuring high-precision microscopes.

A method has been developed for extracting informational spectral components from the signal under study with a minimum error arising from uncorrelated changes in the parameters of this signal by creating sequences of double pulses. A method for synthesizing a test signal is proposed, in which the spectral components used in the analysis of the parameters of this signal predominate and the spectral components adjacent to the informative one are maximally suppressed. The procedure for constructing structures from combinations of double pulse sequences is considered, equations for the amplitudes of their spectral components are obtained, and in accordance with this, the basic requirements and rules for calculating the main temporal parameters of the resulting pulse sequences are determined. The analysis of the areas of sensitivity to changes in the main parameters of the pulse sequence has been carried out. An example of obtaining a test signal with the selection of the 13th spectral component against the background of the suppression of five neighboring ones is considered, and an analysis of the measurement error associated with the instability of the main parameters of the generated pulse sequence is performed. The presented method makes it possible to organize the selection of an informative spectral component with a maximum quality factor by excluding neighboring ones and, at the same time, to increase the accuracy of measuring signal parameters by reducing the influence of the instability of its parameters, which is unattainable using modern approaches, including digital signal processing. The method can be used in the power industry when analyzing the state of operability of electrical machines, for measuring speed and distance in radar, etc.

The paper briefly presents the principal technical solutions for radioactive waste disposal facilities (RWDF), as well as for auxiliary buildings, structures and engineering systems for this RWDF, which ensure safe and economically feasible disposal of radioactive waste (RW) generated from two units of the Belarusian NPP during 60 years of operation and during decommissioning. The suggested conceptual RWDF design includes an assessment of its radiation safety during operation and long-term post-closure safety. It is shown that the suggested RWDF concept ensures safe RW disposal in the period of potential danger of RW taking into account possible external impacts of natural and man-made origin. The aggregate technical and economic parameters of the suggested RWDF project were evaluated both in general and for the first stage of construction. The RW total activity that can be placed in a RWDF, provided the long-term safety of the RWDF is ensured, is 9.0·1014 Bq, including α-emitters – 6.8·109 Bq, transuranium radionuclides – 6.8·109 Bq; for very low-level waste – 4.1·109 Bq. Taking into account the achieved level of detailing of technical solutions in the conceptual design, it can be used at the stage of object design.

A typical process for verification of treatment plans in intensity-modulated radiation therapy is described. The main errors and uncertainties that arise in the course of planning dose distribution and in the process of dose delivery are listed. Methods for comparing dose distributions are considered: the distance to agreement (DTA) and the test for the algebraic dose difference. Formulas for calculating the shift of points of dose distributions, as well as the minimum value of the shift of points, are provided. The influences of global and local normalization and spatial resolution on the interpretation of the results obtained are defined. A methodology for determining reasonable criteria for gamma-analysis of individual dose distributions when verifying plans for irradiation of cancer patients using high-tech radiation therapy methods has been developed. Using the procedure proposed by the authors to establish action limits and tolerances will make it possible to assess the quality of medical care provided in healthcare institutions when using high-tech radiotherapy methods