The results of studies of the structure and microhardness of foil alloys of the lead–tin system obtained by high-speed cooling from the liquid phase are presented. The foil sample had the following dimensions: length – up to 10 cm, width – up to 1 cm, and thickness – 30–80 microns. Melt cooling rate was not less than 105 K/s. A rapidly cooled foil is chara cterized by a dispersed structure. The size of the discharge of tin and lead does not exceed 5 μm. The specific surface of the interfacial boundaries achieve 1.7 μm–1. Due to supercooling, a microcrystalline structure forms in the foil. The average lengths of chords of random secants on lead and tin grain sections in the Pb–73 at.% Sn alloy foil are 0.8 and 1.8 μm respectively. The texture of (111) lead and (100) tin is formed in the foil of alloys of the lead – tin system under certain conditions. The formation of the structure of lead alloys containing from 20 to 95 at.% tin is due to the occurrence of spinodal decomposition of a supersaturated liquid solution, and, in other alloys, due to decay by the mechanism of formation and growth of nuclei of crystalline phases. The stratification of the liquid solution leads to the formation of areas enriched in lead and tin, which contribute to the formation of crystallization centers that are equally distributed in the volume of the foil. The microhardness of the foil alloys, whose compositions are close to eutectic, is less than the microhardness of massive alloys of the same composition, which is associated with the softening effect of grain boundaries and interphase boundaries. Exposure of these alloys at room temperature causes an increase in microhardness due to a decrease in slippage at the boundaries. The decomposition of supersaturated solid solutions of Pb–5 at.% Sn and Sn–1 at.% Pb alloys leads to a decrease in microhardness due to the weakening of the effect of the solid solution hardening mechanism. The results of the study can be used to create fusible solders, bearing alloys, alloys for cable sheaths with improved physicochemical properties.

To detect deviations of required heat treatment temperature of tool carbon steel U8A is one of the important tasks of manufactured products quality assurance. By analyzing researchings, held earlier, it was found that most of instrumental carbon steels standard magnetic characteristics have ambiguous dependence from the heat treatment temperature and cannot be used for purposes of nondestructive testing. Results of researching magnetic parameters of high-quality tool carbon steel U8A, which are good for heat treatment quality testing, are considered. The parameters were defined on steel cylindrical samples by the instrument IMI–I, suited for measuring the ferromagnetic rods magnetic induction during pulsed magnetization in open magnetic circuit. Applicability of the difference δBmp–Br between the magnetic induction of maximum demagnetizing pulse amplitude and the residual magnetic induction for tool carbon steel U8A hardening temperature testing is determined. The coercive force Hс and the coercive force taking on asymmetric magnetic hysteresis loop Hса of the steel can be used to determine underheating and overheating during hardening but these magnetic parameters are inapplicable for hardening temperature testing. It is given that the magnetic induction taking on asymmetric magnetic hysteresis loop Brа and the magnetic induction ВδmH of the magnetic field strength of maximum difference δmH along the axis Н can give measurement sensitivity more than 40 % per 100 °C in low temperature (under 350 °C) tempering testing.

The article describes a method for determining eutectic compositions of 3- and 4-component systems for obtaining cathodes and targets by casting. The eutectic compositions of the alloys in the ternary systems Al–Nb–Si, Cr–Nb–Si and the 4-component system Al–Cr–Nb–Si are calculated. The cathode of the eutectic composition (68Al8Cr4Nb20Si) at.%. was obtained by casting in a vacuum-induction furnace. The microstructure of the cathode material is investigated. Phase and elemental analysis are performed. The melting point of the alloy is determined by DSC (differential scanning calorimetry) and is 570 °C. The results of the research of hardening nitride coatings obtained by vacuum arc deposition in a nitrogen atmosphere are presented. The developed alloy of the Al–Cr–Nb–Si system of eutectic composition, namely (68Al8Cr4Nb20Si) at.% is used as a cathode. The dependence of the microhardness of the coatings on the pressure of nitrogen is determined. The microhardness of the coatings obtained at nitrogen pressure of 7 · 10–2 Pa reached 30 GPa. The phase composition of the coatings is investigated. All samples contain AlN, NbN, Si3N4 phases. The coefficient of friction of these coatings is 0.75–0.8. Cast cathode (68Al8Cr4Nb20Si) at.% can be an alternative to replace the currently used powder and composite cathodes.

The results of research of features of modification of aluminosilicate ceramics by suspension of fluoroplastic, aluminophosphate binder (AFS), non-aqueous compositions of polyurethane components, are presented. Samples of aluminosilicate ceramics for research were obtained by technological methods, including batch preparation operations, sample pressing, pre-annealing and sintering at a temperature of 1200–1350 °C. Polydisperse powders of aluminosilicates obtained by grinding waste of porcelain production (porcelain ware, GOST 28390-89); low-melting clay raw materials were selected as initial components. Modification of surface of aluminosilicate materials was carried out by impregnation of aqueous compositions based on a suspension of fluoroplastic and aluminophosphate binder (AFS), non-aqueous compositions of polyurethane components used in the preparation of polyurethane foam and 5 % solution of polyethylene hydrosiloxane in toluene with the formation of composite coatings on the surface of ceramic materials. It is shown that the application of organic film coatings (based on polyurethane, aluminophosphate binder and a suspension of fluoroplastic-4D, polyethylene hydrosiloxane) leads to formation of a multilayer dielectric material in which there are interface surfaces separating areas with different dielectric properties. In the presence of an external electric field, conditions are created for migration polarization between the crystalline phase of the substrate and the amorphous phase of the coating, due to the redistribution of free charges in the volume of the composite. Moreover, the chemical interaction of AFS with ceramics leads to the smoothing of the surface relief of the aluminosilicate base and the overgrowth of deep pores. Composite “aluminosilicate – AFS-fluoroplastic coating” differs from other materials, primarily in that aluminophosphate binder coating chemically reacts with the ceramic base. The impurity ions introduced during coating application, its composite structure, as well as the heterogeneity of the interface determine the pronounced frequency dependence ε and tgδ, as well as large dielectric losses of the composite in comparison with the original aluminosilicate material.

The article is devoted to the evaluation of the feasibility and efficiency of modernization of the microarc oxidation process (MAO) by changing the conditions and parameters of sparking, as well as the selection of criteria for assessing the quality and predicting the service properties of formed ceramic-like coatings. The predominant role in changing the nature of structure formation and in ensuring the predicted quality and properties of the oxidized alloy is played by the intensity of sparking, which occurs in the process of electric discharges migrating along the treated surface of the object immersed in the electrolyte. Intensity of sparking determines the conditions for obtaining equidistant coatings: the less stochastic the nature of sparking around the oxidized part is, the more evenly and rapidly the thickness of the formed coating increases and its density is higher. These considerations allowed us offering the option of upgrading method of the anode MAO (AMAO), wherein only the anodic component of the current, causing thereby obtaining thin coatings with extensive porosity by stabilizing the process of arcing through the use of the system of quasi cathodes in the electrolysis bath. In this study, we consider the possibility of controlling the parameters of coatings obtained by the AMDO method in its standard and upgraded versions, by fixing in real time the nature of the distribution of spark discharges, indirect evidence of which is the change in the current density over time and the uniformity of the thickness of the coatings created. Taking into account the influence of micro-arc oxidation on the structural and qualitative features of formed layers, it was assumed that the surface of the coating obtained by the modernized method should have a higher quality, one of the indicators of which is a more smooth and uniform relief. Thus, another criterion for the efficiency of the modernized process can serve as amplitude and step parameters of roughness, which, without allowing an objective assessment of the microprofile of the formed coating, can give more extensive information about the nature of the increase in its thickness and quality changes, determining the level of operational capabilities of metal objects with such a coating.

Using the first axiom of statics for equilibrium of a two forces system applied to points of a solid body, it was verified, that the pressure in the zone of contact of a tool with a lens during its abrasive processing by the grinding-free method is unevenly distributed. With this in mind, the nature of the distribution of the pressure profile has been presented graphically, showing the equilibrium condition when the tool is rotated around the center of the spherical surface of the lens relative to its axis of symmetry and the clamping force of the unions that are grinded has been recorded. On that base an expression is proposed for determining the current pressure at an arbitrarily chosen point on the surface of the lens. An expression for determining the continuously changing contact area of the instrument and the lens during its processing by grinding-free method is obtained. The calculation of current pressure at different points of the diametrical cross-section of the contact zone of the lapping surfaces of the tool, performing oscillatory motion, and the lens is performed. As a result, the uneven distribution of pressure in the area under study was revealed, with the minimum value of this indicator taking place in the zone of contact of the tool edge with the lens, and the maximum in the zone of contact of the lens edge with the tool. The observed non-uniformity increases with an increase in the angle of deviation of the tool from the axis of symmetry of the lens. Theoretical and experimental studies of the influence of the tool diameter on the polishing process of the lens under conditions of free grinding, which prevents the occurrence of local error in the marginal zone of the latter due to the pressure drop between the grinding surfaces during the instrument movement, are carried out. At the same time it was found that in order to avoid a “blockage of the edge”, it is necessary to use a tool with diameter of at least 0.8 of the diameter of the lens (in case it is the lower link). The obtained results allow assigning the optimal diameter of the tool depending on the size of the processed lens without preliminary laborious experiments and can be used in optical and optoelectronic instrument making.

In this work, the problem of calculating the efficiency of turbo-units of various types that are part of the equipment of electric and thermal energy sources was solved. In simplified approaches to the representation of turbine units, often used in algorithms of power system optimization programs, in order to reduce the estimated time, the dependence of the plant efficiency on the current power is ignored, the influence of the pressure in the steam extraction of cogeneration turbines to cover the heat load and the idle speed of the turbines are not taken into account. These approaches are easy to use and implement, however, they can introduce noticeable errors in the optimization results due to the lack of consideration of parameters and dependencies that occur in real equipment operation modes and significantly affect the amount of fuel used by the optimized system. In contrast to the simplified approach, energy characteristics were used in the work to determine the efficiency factors characterizing the efficiency of turbine units. This allows providing a more accurate assessment of the effectiveness in various operating modes without significantly complicating the algorithm with a slight increase in the estimated time. Using the proposed approach showed the presence of a noticeable refinement of efficiency compared to simple models and, therefore, the feasibility of representing turbine units using energy characteristics in program algorithms designed to optimize energy systems.

The basic electrophysical and technological parameters of a CDI desalination plant designed for long-term operation, based on the principle of salt solution deionization on electrodes with a developed surface, have been studied. The proposed equipment for water demineralization uses a simplified design with pumping the solution through electrodes (“flow through electrodes”), which allows bypassing without relatively expensive ion-exchange membranes. Non-woven felt “Karbopon-V-Aktiv-200-65A” was used as the electrode material, the estimated value of the specific surface of the material of which, according to the results of measurements by the method with the deposition of acetone, amounted to ~ 1000 m2/g or more. Also, the advantages of the proposed CDI desalination plant are the absence of highly loaded power elements, the use of corrosion-resistant materials and the reliability of the electrode stacking scheme, which makes it possible to count on its long-term and reliable operation. Various possibilities of operational adjustment of the desalination plant modes are demonstrated – reduction of the discharge period due to the application of voltage pulses of reverse polarity, increasing efficiency by organizing a procedure for taking into account the real voltage at the working electrodes inside the CDI cell. The high-energy efficiency of demineralization is determined by the relatively low operating voltage of ~ 1 V. It is established that with increasing amperage, salt removal is more efficient, respectively, the degree of desalination is higher at a higher current: the working period of 30 minutes corresponds to the degree of desalination of ~ 20 % at a voltage of 1.4 V and ~ 30 % in the 1.6 V mode. The possibility of increasing the desalination capacity to ~ 100 g of salt over a half-hour period was noted. Possible ways to further improvement of the performance of the equipment presented in the article are identified.

Data preparation for computer simulation of cross-wedge rolling (CWR) process based on ANSYS/LS-DYNA finite element code is considered in the article. In order to automate the process of developing CWR models and performing their finite element analysis, specialized software (PSPD) was developed. This software provides creation of a finite element (FE) model of the rolling process considering the specifics of CWR technological processes and different aspects of the application of the finite element methods (FEM) in the metal-forming processing. PSPD interacts with the base system through APDL scripts, that describe individual sequences of actions for preparing the FE model and choosing solver parameters to run the task. PSPD provides a graphical user interface (GUI) which allows users to enter necessary data for generating APDL scripts, the model builds automatically in ANSYS in batch mode when scripts are run. Also, PSPD provides preparation of the FE model for solver and provides managing the calculation process. In addition to describing the functionality and features of the program and its GUI, the article provides techniques and methods of FE model preparation for computer analysis using the developed software as well as the main steps of creating FE model in ANSYS/LS-DYNA, which are automated in PSPD.  PSPD can significantly reduce the demand for knowledge in the field of computer simulation to the engineers engaged in the development of tools and technical processes for rolling, it allows quickly creating and modifying FE models, performing CWR research for a variety of input data of process technology and solver parameters.

The results of research of non-stationary heat exchange in combined packages intended for creation of special water- and heat-resistant protective clothing of firefighters from dangerous and harmful factors during emergency rescue and other urgent works, with participation of non-toxic substances, acid solutions, alkalis, oil and petroleum products, liquid toxic substances, as well as during operation in water with temperature from 0 to 70 °С are presented. The stability of clothing material packs has been investigated as a transient heat exchange process in a multilayer plate with ideal thermal contact at the joints of the layers. The unlimited plate is heated on both sides under different heat exchange conditions according to Newton’s Law, with constant action of the heat source on one of the surfaces of the hot liquid contacting through the waterproof thin surface. Second surface of the plate interacts with external medium, temperature of which varies according to linear law. At solving the equation of non-stationary thermal conductivity with nonlinear transport coefficients, linearization methods are used based on the approximation of nonlinear coefficients, such that nonlinear equations become approximately linear. The entire heat transfer process is divided into a plurality of small-time intervals within which the transfer coefficients are constant. The zonal method of investigation of non-stationary thermal conductivity in clothing packages establishes equations for calculation of temperature, densities of thermal flows, distribution of temperature across thickness of clothing packages. It has been shown that under accepted calculation simplifications, parameter values are well consistent with the experiment. The composition of the clothing package is proposed, which meets the technical requirements of TУ BY 101114857.082-2015 “Personal Protective Kits”.

In the present work the patterns of relationship of photonic radiation dose rate from Cyclone 18/9HC water cooling system were studied at production of positron-emitting nuclides. Reaction (n, p) was shown to be the main source of activation nuclides in cyclotron cooling water at 18F production, resulting in formation of 16N (T1/2 = 7 s) from 16О. In water targets with high accumulated dose, when beam partially irradiates a target body, proton-induced reactions: 16О(p, α)11С and 18О(p, n)18F take place. Fluoride 18F–, carbonate 11СО32– and hydrocarbonate Н11СО3– anions, formed in proton-induced activation reactions, efficiently precipitate on anion-exchanging resin during water circulation resulting in circuit purification from the named radionuclides. Activation of cooling water does not occur at irradiation of gas targets. Projected annual dose for cyclotron operator from cooling water activation is less than 1 % of annual dose limit for personnel from technogeneous radioactive sources. In order to minimize operator`s accumulated doses it is recommended to decrease the duration of personnel activities at the distance less than 1 meter from heat exchanger during 18F production. At operation of water targets with absorbed dose higher than 2500 μA·h it is desirable to conduct the preventive maintenance of water cooling system not earlier than in half an hour after the end of irradiation and with mandatory dosimetry control. To decrease the activation of impurities it is essential to use only deionized water in cooling circuit. In case of its specific conductivity increase due to corrosion the coolant should be replaced promptly.

Assessment of radiation effect on nuclear power plant staff was made for beyond design basis accident (4 hours period). The considered accident scenario includes emergency radionuclide emission through containment bypass. Assessment of radiation effect on NPP staff was done on the basis of radionuclide concentration distribution on site considering typical infrastructure. Concentration mapping was calculated by developed program module for COMSOL 3.5a application. The obtained data included average volume radionuclide activities in lower air layer, total inhalation dose, effective dose of external exposure, equivalent and effective dose in thyroid and total effective dose for NPP staff during beyond design basis accident. Doses from radioactive cloud (external exposure) and from inhalation (internal exposure) were estimated for the following radionuclides: 137Cs, 134Cs, 131I, 133I, 90Sr. In the case of selected beyond design basis accident the total effective dose of staff is 61,98 mSv for the first 4 hours after the accident beginning. This number is slightly above the threshold of the allowable annual dose limit for personnel in emergency situations (50 mSv). Taking into account that short-lived iodine radionuclides 131I и133I give the main contribution in the dose (50.23 mSv including 27.23 mSv for thyroid), such emergency actions as respiratory protection and iodine prophylaxis for the staff can significantly decrease the received doses.

Current work is aimed at the analysis of the fission products decay influence during fuel reloading, when calculating the accumulated fission products activity for the VVER-1200 reactor fuel campaign. The Bateman problem solution based technique was used for calculations, within the framework of the two fissile nuclides approximation. The fission products producing process for the VVER-1200 reactor stationary campaign is considered, taking into account the reactor shutdown periods for refueling and without taking them into account (instant reload approximation). It was shown, that the instant reload approximation for fission products activity calculations gives the similar accurate result, as calculations with taking into account the shutdown periods. The results can be used to significantly simplify the calculations of fission product activity accumulation in nuclear power reactors.

A technique has been developed of justification of possibility and expediency of extraction of the reserves left, which were mined more than 40 years ago by chamber system with maintenance in a safe condition of underground mining constructions. The methodology includes the identification by studying the geological and mine surveying documentation of districts with reserves in the mine fields; calculation of volumes and quality indicators of reserves left at these areas; assessment of a condition of mine workings that have direct access to the reserves concerned, and the possibility of their re-use, as well as the possibility of new development workings and ensuring their sustainability and maintenance in a safe condition; establishing the features of geomechanical processes in the rock mass and the presence of dangerous violations in the worked-out zone, the degree of the violation and the nature of the deformation of rigid and pliable pillars in the extraction chambers, including the use of specially conducted  mine openings; development of technological schemes for safety extraction of abandoned minerals. With the use of this technique for the first time the technological opportunities and economic feasibility of mining minerals from the treatment units of the First and Second Mines of JSC Belaruskali, worked out more than 40 years ago, has been estimated. The possibility of excavating abandoned reserves in the sylvinite layer 4 and layers 2, 2–3, 3 in inter-chamber pillars in areas previously worked out by the chamber system with total volumes of more than 57 million tons is shown. The results of surveys of the state of capital and development workings are given, according to which for the re-mining of most of the worked-out blocks, new capital and development workings will be required. The results of visual examinations of panel and block drifts, their conjugations with treatment passages, as well as the state and degree of violation of inter-passage and inter-chamber pillars in the treatment chambers are described. Possible methods for re-mining the reserves of the Third potash horizon with treatment longwalls and a chamber system are proposed, which are distinguished by high technical and economic efficiency and mining safety.