Fluorine containing diamond-like carbon (DLC) coatings were obtained by CVD deposition using the destruction of gaseous hydrocarbons by a high-energy ion source with an anode layer. The chemical composition, structure, surface energy, mechano-tribological characteristics of the synthesized thin-film material were studied. It has been shown that the fluorine content in the deposited coatings reaches 31 at.%. It has been established that the presence of fluorine in the DLC coating promotes the formation of nanodispersed graphite-like structures. Fluorine containing coatings with a high content of sp2 hybridized carbon atoms and graphite fragments show a decrease in hardness. Such coatings have a very low coefficient of friction at the level of 0.03–0.07 due to the low surface energy, which can be reduced by 1.5 times compared to pure DLC. It has been established that different fluorine contents in thin-film diamond-like carbon material have different effects on the interaction of the DLC coating with polar/non-polar dielectrics. The research results can be used for the technology of producing solid lubricants in friction units of machines and mechanisms, and are also of interest for medicine, the food industry, the production of plastics, and chemical fibers as chemically inert and corrosion-resistant coatings.

In this work, we analyzed and summarized the results of experimental studies of the characteristics of air-mechanical foam generated on the deflector type sprinklers and in the foam generating devices with mesh using three brands of general purpose foam concentrates, one brand of special purpose foam concentrate and one brand of foam concentrate used to extinguish fires as a wetting agent. As a result of the analysis, a linear dependence of the volume stability on the expansion rate of the foam was established, and the influence of physical characteristics (wetting ability, surface tension and dynamic viscosity) and the jet speed of the foam concentrate solution on the proportionality coefficient of the established dependence was determined. This dependence relates the stability and expansion rate of foam not only when using deflector type sprinklers for automatic extinguishing systems, but also using nozzles of fire barrels and other foam-generating devices that allow the generation of low-expansion air-mechanical foam, and does not depend on the geometric dimensions of the devices used. The resulting equation makes it possible to determine the stability of foams using the value of their expansion rate. It will help to reduce the time and money spent on experimental determination of the foam stability.

The kinetics of convective drying of thin wet thermal insulation materials based on the relative drying rate and relative moisture contents has been studied. Processing of experimental data on drying of various wet materials has established that the relative drying rate is related to the relative moisture contents, which are the ratios of the current moisture content to its critical and initial values. Based on the functional dependence of the relative drying rate on the relative moisture contents using the processing of the experiment on drying of ceramics, felt, and asbestos, equations for calculating the drying time are obtained. The dependence of the relative drying rate on the ratio of the current moisture content to the critical one is given. Zonal methods for calculating the drying time are given, based on the drying rate curve. An expression for determining the drying coefficient is developed. Based on the analysis of experimental data on drying porous ceramics, sheet asbestos, and wool felt, graphs of the dependence of the relative drying rate on the ratio of the current moisture content to the initial one are constructed. Dependencies for determining the critical moisture content of the material are given. The considered method of processing experimental data allows obtaining all the main equations for calculating the kinetics of the drying process. A variant of estimating the drying time based on one experiment with a short time interval is given. A comparison of the calculated values according to the equations with the experiment is performed. The spread of the calculated values is in the range of experimental error. The formulas for calculating the drying time obtained without plotting the drying rate curve allow significantly reducing the time of processing the experimental data and can be applied to other materials.

The experimentally established regularities of changes in electromagnetic radiation reflection, transmission and absorption characteristics in the frequency range of 2.0–17.0 GHz of materials are presented. These materials contained powdered activated birch charcoal impregnated with chlorides aqueous solutions (calcium chloride, magnesium chloride and sodium chloride). Using the established regularities, it was determined that materials based on powdered activated birch charcoal impregnated with calcium chloride aqueous solution are radioabsorbing if they interact with electromagnetic radiation in the frequency ranges of 3.5–4.5 and 5.5–17.0 GHz. In turn, materials based on powdered activated birch charcoal impregnated with magnesium and sodium chlorides aqueous solutions are radioabsorbing if they interact with electromagnetic radiation in the frequency ranges of 2.0–17.0 and 2.0–7.5 GHz (magnesium chloride solution), 10.0–17.0 GHz (sodium chloride solution). Electromagnetic radiation absorption coefficient values of the studied materials reach 0.95. These materials seem promising for the manufacture of partitions to shield sectors of premises where electronic devices sensitive to electromagnetic interference are located.

The structure of a hardware and software complex for the study of DC electric machines and a mathematical model of its electromechanical part taking into account the influence of temperature on the resistance of the armature winding have been developed. The hardware and software complex is implemented on the Arduino Uno board. A distinctive feature of which is the modular structure, which allows conducting research on DC electric machines in various operating modes (start-up, armature speed control, reversing, braking). In addition, it is possible to implement various laws of changing the load moment. For this purpose, the hardware and software module include the studied and load DC electric machines, which are mechanically connected to each other by means of a coupling and operate in motor and generator modes, respectively. The proposed model makes it possible to describe electromagnetic processes in DC electric machines taking into account the influence of temperature on the resistance of the armature winding, as well as overheating of individual parts of the electric machine. The proposed hardware and software module can find practical application in research laboratories in the study of DC electric machines in various operating modes.

In this paper there were studied the mineral composition and sorption properties as well as filtration properties of natural clay samples from “Gorodnoe” deposit of Brest region and “Markovskoe” deposit of Gomel region. It was determined that clay mineral montmorillonite of the samples contains illite phase in the structure, which is 4,8 wt.% in “Gorodnoe” sample and 3,6 wt.% in “Markovskoe” sample. The illite phase was shown to contain highly selective sorption sites for ¹³⁷Cs. ⁸⁵Sr sorption mostly takes place on montmorillonite. It was determined that model mineralized solution (the solution imitating chemical composition of water solution if water penetrates a radioactive waste disposal and consequently passes through concrete, Na-bentonite and again concrete layers) doesn’t affect ¹³⁷Cs sorption, but significantly affects ⁸⁵Sr sorption. Distribution coefficients (K_d ) of ¹³⁷Cs sorption on studied clay samples are higher than 10³ dm³ /kg, indicating high sorption properties of the clays towards ¹³⁷Cs. K_d ⁸⁵Sr for sorption on the clay samples in the model mineralized solution is 30 times lower than Kd ¹³⁷Cs mostly because of competition between strontium and calcium ions. It was determined that filtration coefficient values of clays from “Gorodnoe” and “Markovskoe” deposits are 2,4 and 1,3 times higher after being treated with the model mineralized solution than the filtration coefficient values for raw clay samples. Hence, the clay from “Markovskoe” deposit is more resistant to the influence of the model mineralized solution than the clay from “Gorodnoe” deposit. The overall results of the research state that the clay from “Markovskoe” deposit can be used in the underlying layer of low- and medium-level radioactive waste disposal facility at NPP.

During the work, the speciation of iron (III) was studied at the concentration of ~ 1∙10^–5 mol/dm³ in aqueous solutions in the presence of boric acid at a concentration of 5–20 g/dm³ in a wide pH range using ion exchange, ultrafiltration and centrifugation methods. The regions of existence of ionic and nonionic forms of iron (III) were determined by ion exchange in solutions with different boric acid concentrations. Experimental data have shown that the pH of the onset of iron (III) colloid formation shifts in the presence of boric acid. The formation of complex compounds of iron (III) with polyborate ions in the neutral – slightly alkaline pH region was established by ultrafiltration and centrifugation. As shown in the paper, the increase in the concentration of boric acid in solution leads to the increase in the region of existence of the supposed complexes. The identified features of the behavior of iron (III) in solutions containing boric acid determine the possibility of using ion exchange and membrane separation methods for purifying solutions. Information about the physical-chemical properties of various metal-ions can provide optimal conditions for the purification of liquid radioactive waste at various nuclear industry facilities.

Probabilistic safety analysis of the loss of coolant accidents in the VVER-type reactor plant has been performed taking into account the internal initiating events of the reactor primary circuit large leakages. Swedish program code RiskSpectrum PSA was used for probabilistic safety analysis. Logical probabilistic models of the accident scenarios of the large primary circuit leakages in the VVER-type reactor were developed taking into account different operation modes of the power plant unit. Critical paths and probabilities of the accident scenarios occurrence of the large leakages were identified. The critical path of development of the reactor primary circuit large leakages accident with large leakages of 140–346 mm diameters is the accident sequence with a leak in the pipeline to the reactor pressurizer vessel. It has been established that the greatest contribution to the failure of safety functions during this initiating event is made by the failures due to common causes of the supporting systems (cooling and ventilation systems), critical consumers cooling circuit, emergency injection system. The critical path of the accident with large leakages of 346–850 mm diameters is the accident sequence with the rupture of any of the four primary circuit loops. The greatest contribution to the failure of safety functions during this initiating event is made by the failures due to common causes of the emergency injection system elements. Based on the accident analysis, recommendations for increase of performance reliability of safety functions during the large leakages accidents under all operation states of the nuclear power plant unit were given. In order to increase reliability of safety systems, it is necessary to eliminate failures due to common causes of equipment, increase the reliability of operation of supporting systems, change the maintenance and checking equipment procedures.