The influence of the modes and conditions of laser surface alloying of the corrosion-resistant 95Cr18 steel (440C, 440B—analogues in the United States) was investigated. The structure, quality, and geometric parameters of the surface layers created as a result of laser exposure were studied. Powders of chemical compounds, such as B4C, WC, TiB2, W2B5, TiSi2, and HfSi2, were used for alloying; processing in an argon medium was carried out using a fiber laser with a wavelength of 1.06 microns. During the experiments, optimal parameters, such as the beam focusing size, scanning speed, and radiation output power, were selected. With increasing power, the volume of the melt bath increased as did both the depth and width of the alloying zone. Thus, with a laser power of 2 kW, the width of the doping zone reached ~3 mm. The depth of the alloyed layers on the surface of that steel was 400–700 microns in the power range of 1–2 kW. The microhardness of the alloy zones of 95Cr18 steel could be at the level of 4500–12 000 MPa. At the same time, with a decrease in the depth of the alloyed layer, the microhardness may increase due to an increase in the concentration of alloying components. For boron carbide in the solid phase quenching zone, the maximum increase in the microhardness of the surface layer reached 14 000 MPa.

The paper proposes a method of constructing an ultrasonic system that determines the stability of thermosonic microwelding of gold wire with a diameter of 17.5–50 µm when assembling electronic products in metal-ceramic enclosures. A simulation of waveguide was conducted at the standard frequency of ultrasonic oscillations of 66 kHz and an increased frequency of 136 kHz.

A possibility of the plasma electrolytic treatment of a heat-resistant nickel alloy ChN77TiAlB, which leads to the removal of edge cracks, a decrease in hardness, and an increase in wear resistance, is shown. The volt-ampere and volt-temperature characteristics of the plasma electrolytic treatment, typical for anodic processes, are revealed. Changes in the morphology and roughness of the surface and the structure and microhardness of the surface layers are considered. It was established that the treatment in an electrolyte based on carbamide and ammonium chloride leads to the formation of nitrocarburized layers without the formation of compounds. The combined effect of both high-temperature oxidation and anodic dissolution on the morphology and roughness of the surface was determined. Tribological tests were conducted using the ball-on-disk scheme, which showed the best results after treatment at 900°C (reduction in volumetric wear by 15.7 times), when a reduction in roughness (by five times) and the presence of thick oxide layers determine a uniform running-in period, reaching a lower value of the friction coefficient, and homogenization of the alloy, accompanied by the removal of cracks, determines a softer wear mechanism. Positive results were obtained in abrasive wear tests: after treatment at 600 and 900°C, volumetric wear decreased by 2.6 and 2.2 times, respectively.

The paper presents the results of calculations and experiments to determine the primary amplitude and time characteristics of electrical breakdown in long air gaps in a point-to-plane double-electrode discharge system (DEDS) by a standard switching aperiodic high-voltage pulse of the time configuration, Tm/Тp ≈ 200 μs/1990 μs, of positive polarity. Approximate calculation relations are obtained to find the breakdown time, Td, breakdown (discharge) voltage, Ud, and breakdown strength, Ed of a strong electric field for this DEDS, averaged over a minimum length of lmin ≥ 1 m of these gaps. The proposed engineering approach to determining the values of Td, Ud, and Ed is based on the results of an approximate calculation in a long air gap of a point-to-plane DEDS of a sharply inhomogeneous strong electromagnetic field that produces a spherical zone with a radius ri of active impact ionization of its atmospheric air by electrons. This occurs near the lower sharp edge of the upper potential electrode point of the DEDS, wherefrom a positive discharge leader develops towards the lower grounded electrode plane of the DEDS.

Surface characteristics of the clay-carbonate diatomite and its adsorption properties with respect to methylene blue (MB) were investigated. The equilibrium isotherms were modeled by the Langmuir, Freundlich, and Dubinin–Radushkevich equations. The Langmuir model more adequately described the experimental data with a correlation coefficient of 0.9783 and a maximum adsorption capacity of 112.8 mg/g. The separation factor was 0.143, indicating the favorability of the sorption process. The treatment of the experimental kinetic data showed that the pseudo second order model better describes the kinetic curves of the MB sorption. Intraparticle diffusion does not control the MB sorption rate, and film diffusion is the main contributor to the rate limitation. The activation energy for sorption, calculated using the Dubinin–Radushkevich model, was 17.4 kJ/mol, indicating the predominance of physical sorption. The results show that this sorbent can be used for the purposes of water purification from organic pollutants.

The paper studies the structural and physicochemical properties of binary polymer mixtures based on ethylene-propylene copolymer (EPDN) and nitrile-butadiene rubber (NBR) in order to improve their technological and thermal stability. A comprehensive analysis of the influence of composition and plasticization conditions on the processes of crosslinking, structure formation, and thermal-oxidative destruction was carried out. It was experimentally established that an increase in the proportion of NBR promotes the development of a spatial network due to radical reactions activated by double bonds and polar groups. Optimal viscosity, elasticity, and gel content are achieved with an EPDN to NBR ratio of 60 : 40. The results are confirmed by both spectral and rheological analyses as well as by calculating the degree of crosslinking using the Flory–Rehner equation. The work demonstrates the potential of targeted modification of EPDSN-containing compositions using reactive elastomers to create heat-resistant and durable polymeric materials.

The current state of agricultural land makes us think about the need to search for new, innovative methods of weed control since relying only on intensive chemical and historically justified mechanical processing of soil areas is not always justified today, due to the fact that nature is cumulatively inflicted with environmental damage and humus, and organic matter reserves in the soil continue to be uncontrollably depleted. It is proposed to use electropulse weeding as a technologically and ecologically justified alternative to traditional methods. The conducted studies on the electrical conductivity of the weed plant tissue and processing current flow circuits, identifying the option of supplying electrical energy and damaging doses of energy, made it possible to justify the structure of the unit, consisting of a mover (a wheeled tractor) and an electrotechnological unit, as well as to evaluate the economic and agro-technological efficiency of its use in agricultural technologies. In principle, the unit consists of three main structural blocks: a movement power unit (a universal row-crop wheeled tractor), a power source, and an electrode system. In order to achieve lower cost of the device and greater maneuverability of the unit, it is preferable to choose the option with a trailer generating unit and mounted units for increasing voltage, forming pulses and an electrode system. Analysis of the total energy costs during the electric pulse treatment of soil areas from weeds and unwanted plants, and their assessment during cultivation of winter wheat of the Mironovskaya Yubileynaya variety on the black fallow on the lands of Volgograd oblast made it possible to reasonably consider such treatment to be less energy-intensive compared to mechanical cultivation and chemical weeding on an area of 100 hectares, and also implemented with a minimal negative impact on the environment.

The electrodeposition and properties of the Co–W alloy obtained from concentrated gluconate electrolytes were studied. It was shown that high-quality alloy coatings with a high current efficiency are formed by variating the precursors from 0.1 to 0.5 M at a concentration ratio of the Cit ligand and alloy-forming components $${\text{C}}{{{\text{o}}}^{{2 + }}}{\text{/WO}}_{4}^{{ - 2}}$$ of 5 : 1. Based on the results of the X-ray structural analysis, it was concluded that the Co–W alloy can be formed as a polycrystalline substitutional solid solution and a thermodynamically stable Co3W compound, which, depending on the content of the alloying element tungsten, can be either polycrystalline or finely dispersed. High values of microhardness of the alloy of 800 kg/mm2 obtained at a current density of 1 A/dm2 can be associated with the electrochemical deposition of the Co3W intermetallic compound, which has a high microhardness.

The article discusses the changes occurring in polypropylene and its compositions with silicon dioxide, which occur under the influence of electro-thermal polarization. The dependence of the piezoelectric properties of polypropylene compositions on the percentage of the additive has been revealed. The present study identifies the dependence of the piezoelectric properties of polypropylene compositions on the percentage content of the additive. Furthermore, it demonstrates that the dependence of the charge of polymer compositions of polypropylene with silicon dioxide on the filler content can be described by an exponential curve with a peak at 3% filler content. Furthermore, the quasi-static piezoelectric coefficient of polypropylene compositions with 3% silicon dioxide has been examined in relation to both preload and the spectrum of thermally stimulated depolarization of the composite.

A minimal theoretical model for describing the dynamics of localization of a shared electron in a pentamer nanocluster in an external low-frequency electric field, taking into account the electron-vibrational interaction, is proposed. Based on the given model, the system of differential equations was obtained regarding the time dependences of amplitudes of the probability of finding an electron on different centers of a pentamer. This model was used to describe the pentamers of linear and square-planar configurations. For those two types of the pentamer configuration, the numerical calculations were performed at different values of model parameters. The proposed model is characterized by the fact that the centers of the nanocluster are considered as weakly tunnel-coupled, and the electron-vibrational coupling with the ligand environment on each of its centers plays a significant role. Moreover, tunneling is taken into account only between the nearest centers of the nanocluster, while the cluster centers are considered equivalent. The control role of an external electric field was revealed so that the variations of its intensity amplitude and frequency allowed for realizing the various electron localization regimes in the pentamer nanocluster. By setting up the values of those electric field parameters, the duration of the full localization of an electron at a certain cluster center (or centers) was regulated as was the rate of switching the localization of an electron to another cluster center (or centers) and the form of the overall distribution of electron density in the nanocluster.