A design of an electrostatic mirror energy analyzer for the analysis of charged particle beams based on a new ly synthesized field is proposed. The electrostatic field of the analyzer is formed as a superposition of an axi ally symmetric multipole field and a spherical field. The structure of the electrostatic field formed by the su perposition of axially symmetric octupole and spherical fields has been investigated. It is shown that varying the parameters determining the contribution of multipole components allows controlling the aberration prop erties of the electron-optical system. Conditions for compensating for second- and third-order aberrations have been obtained by selecting appropriate values for the weight coefficients of the hexapole and octupole components, which allows for a significant improvement in the focusing properties of the field. Numerical modeling of the electron-optical system and calculation of charged particle trajectories were carried out using the “FOCUS” simulation program. Two regimes of angular focusing were found. The first mode corresponds to second-order angular focusing at a particle input angle of 68°, while the second regime implements third order focusing at an input angle of 90°. The instrumental functions of the device were constructed, and the relative energy resolutions and luminosities of the analyzer were evaluated. The proposed electron-optical schemes can be used in the development of high-resolution spectrometers for analyzing charged particle beams in space research, as well as spectrographs for the energy-angle analysis of solid surfaces.
Laser Rayleigh Scattering (LRS) serves as a critical non-intrusive diagnostic for boundary layer thermometry; however, its accuracy is significantly compromised near pyrolyzing surfaces due to transient shifts in gas composition. In Poly(methyl methacrylate) (PMMA) environments, the rapid efflux of high-molecular-weight fuel vapor displaces the inert calibration gas, leading to a systematic bias that is frequently misinterpreted as a physical temperature decrease. This research resolves this diagnostic ambiguity by developing a transient, one-dimensional coupled thermo-kinetic framework. The model integrates solid-phase Arrhenius degradation kinetics (E = 230 kJ/mol) with gas-phase species transport equations, utilizing the Method of Lines (MOL) to solve the resulting stiff system of partial differential equations. Quantitative results demonstrate that the dis placement of the helium tracer by Methyl Methacrylate (MMA) monomer increases the effective Rayleigh scattering cross-section by a factor of 3.1. It is shown that failing to account for this compositional shift leads to a temperature underestimation of approximately 650 K during the quasi-steady gasification phase (TS ≈ 593.4 K). Furthermore, the simulation confirms that the characteristic “temperature dip” observed in raw LRS experimental data at the onset of ignition is a compositional artifact rather than a thermal phenome non. This work establishes a physics-based protocol for de-biasing optical measurements through dynamic correction factors (α), providing a scalable methodology for high-fidelity thermometry in variable composition pyrolyzing systems.
Accurate determination of intermolecular potential parameters is essential for predicting thermophysical properties of real gases, particularly heavy polyatomic fluorides of industrial relevance. In this study, Morse potential parameters for MoF6, IF5, and WF6 gases were obtained using a nonlinear least-squares fitting algo rithm based on Lennard–Jones (12–6) interaction energy data, where the root-mean-square error (RMSE) was used as the minimization criterion. The obtained parameters were validated by calculating the second virial coefficient, heat capacity at constant pressure, and speed of sound, and comparing the results with available experimental data over the temperature range 298–400 K. Quantitative accuracy was assessed using RMSE, mean relative error (MRE), and correlation coefficient (R). For the second virial coefficient, RMSE values were 31, 264, and 149 cm3·mol–1 for MoF6, IF5, and WF6, respectively, with corresponding MRE values of 3.3 %, 11 %, and 18.5 %, and strong correlations (R ≥ 0.978). In addition, deviations for speed of sound and heat capacity remained within 1–2 % and below 1 %, respectively, with R > 0.996. These results demonstrate that the proposed approach provides a reliable and computationally efficient framework for modeling inter molecular interactions and predicting thermophysical properties of such gases.
This study presents the experimental results of high-temperature oxidation testing under actual operating con ditions in a thermal power plant of gradient and homogeneous composite NiCr–Al coatings produced by the detonation spraying method. To characterize the degradation mechanisms of the tested coatings, systematic analyses were performed, including phase composition evaluation, and detailed microstructural examination using scanning electron microscopy (SEM). The evolution of oxide layers and elemental redistribution across the coating thickness were also assessed to clarify the influence of coating architecture on protective perfor mance. The experimental results demonstrated that the gradient composite NiCr–Al coatings exhibit superior resistance to high-temperature oxidation compared to homogeneous coatings. The gradient architecture effec tively preserved structural integrity and promoted a more uniform distribution of aluminum and chromium within the coating thickness. This compositional optimization facilitated the formation of continuous and ad herent protective oxide layers, predominantly Al2O3 and Cr2O3, which significantly reduced oxidation kinet ics and inhibited coating degradation. In contrast, the homogeneous NiCr–Al coatings showed noticeable aluminum depletion, crack formation, and oxide scale spallation after prolonged exposure to high temperature industrial conditions. The findings of this study confirm that gradient NiCr–Al coatings deposit ed by detonation spraying represent a promising protective solution for components operating in severe high temperature and corrosive environments, offering improved durability and extended service life for industrial and energy related applications.
This study investigates the electrochemical oxidation (EO) of methyl orange (MO) as a model azo dye pollu tant representative of textile and industrial effluents, using boron-doped diamond (BDD) and dimensionally stable anode (DSA) electrodes under systematically optimized conditions. Model solutions were prepared in ultrapure water with 0.1 M Na2SO4 as the supporting electrolyte. Batch experiments were conducted in gal vanostatic mode at 25 ± 1 °C with constant stirring (300 rpm), varying current densities (10–50 mA/cm²), pH values (2–10), and initial methyl orange concentrations (50–500 mg/L). BDD anodes achieved 94.3 ± 2.1 % pollutant removal within 120 min at optimal conditions (30 mA/cm², pH 3.0, 200 mg/L), significantly outper forming DSA (87.6 ± 3.3 %) and platinum (68.7 ± 4.5 %) electrodes. Electrochemical impedance spectrosco py (EIS) using a Randles R(Cdl(RctW)) equivalent circuit revealed a 73 % decrease in charge transfer re sistance (Rct: 385 Ω → 104 Ω) with increasing anodic potential (1.0–2.5 V vs. Ag/AgCl), confirming Butler Volmer-controlled oxidation kinetics. The apparent rate constant kapp = 0.0315 ± 0.0018 min–1 for BDD was 1.68-fold greater than for platinum. Total organic carbon (TOC) analysis confirmed near-complete minerali zation (96.8 ± 1.5 % TOC reduction) with BDD. Specific energy consumption was minimized to 8.2 kWh/m3, indicating the potential competitiveness of this approach for treating dye-containing effluents. At Nigerian electricity tariffs (₦45/kWh), estimated treatment cost is ₦369/m³, suggesting feasibility for industrial appli cation in developing economies, pending validation with real effluent matrices.
The development of thermoelectric materials has attracted considerable attention with the emergence of a new class of high-entropy materials. Their fabrication is typically based on solid-state synthesis and involves prolonged mechanical mixing of powder precursors, high-temperature heat treatment, and multiple repetitions of these operations. The paper addresses the issues of accelerating the manufacturing process of highly en tropic ceramics for thermoelectric applications through the use of electron beam processing. The effect of cy clic processing of a powder mixture of initial reagents in air with a high-energy electron beam (E = 1.4 MeV) on the sintering of compacts was studied using high-entropy perovskite ceramics (Ca0.2Sr0.2Ba0.2Pb0.2La0.2)TiO3 as an example. The electron beam current was 4 mA (5 treatment cycles) and 5 mA (4 treatment cycles), with mechanical grinding of the powder after each irradiation step. It was found that electron beam treatment enhances the compaction/sintering kinetics. The efficiency of the treatment in creases with the number of cycles. As a result, the sintering process is accelerated, leading to increased ce ramic density and mechanical strength. These improvements are attributed to the formation of the high entropy phase (Ca0.2Sr0.2Ba0.2Pb0.2La0.2)TiO3 in the powder mixture as a result of electron beam processing.
The article discusses the application of the electric pulse method of coal grinding for obtaining raw materials for water-coal fuel. It is noted that the combustion efficiency of water-coal fuel is largely determined by its granulometric composition, which is traditionally formed using mechanical mills. Despite their widespread use, such systems are characterized by high energy consumption, intensive wear of working parts, and signif icant operational costs. Therefore, the use of electric pulse discharges as an alternative method of coal disin tegration is of particular interest. The study analyses the physical principles of electric pulse grinding, which is based on the impact of short-term high-voltage discharges that cause local micro-explosions, shock waves, and destruction of the material’s structure. Special attention is given to the electrode system of the electric pulse installation operating in a heterogeneous “water-coal” environment, including the selection of materials, electrode geometry, and discharge parameters. The design and operating principle of the experimental electric pulse installation are described. The aim of the study is to justify and develop an effective electrode system for the working channel of the electric pulse installation for obtaining water-coal fuel raw materials with min imal energy consumption and increased equipment reliability. It has been established that using the inner sur face of the working channel as the negative electrode increases the yield of the finished product with a pow der diameter ranging from D < 0.04 mm to D < 0.2 mm. Additionally, there is a decrease in the size of the coal powder with a diameter of 0.4 mm < D < 0.7 mm. The obtained results allowed us to choose the optimal variant of the electrode system in the working channel during the grinding of raw materials using the electric pulse method
A theory of unstable wave excitation in a two-valley semiconductor subjected to a temperature gradient and constant external electric and magnetic fields is developed. The effects of the external electric field, the tem perature gradient, the magnetic field generated within the sample by hydrodynamic motion, and the electric field arising from charge-carrier redistribution are taken into account. It is shown that the sample size plays an important role in the excitation of unstable waves. The frequency of hydrodynamic waves is shown to be twice that of the thermomagnetic waves excited in the sample. Analytical expressions for the frequencies and growth rates of the unstable waves are obtained. Analytical conditions for the external magnetic field required to excite hydrodynamic unstable waves are derived, and the ranges of the external electric field corresponding to wave excitation are determined. It is established that the transition time of charge carriers from the lower valley to the upper valley is shorter than the transition time from the upper valley to the lower valley. The analysis is based on a linear theory and assumes that carrier mobilities differ only slightly from their equilib rium values. For the first time, the electric field generated within the semiconductor is taken into account, demonstrating the feasibility of developing new Gunn-effect devices, including generators and amplifiers. The proposed mechanisms are consistent with available experimental data on the Gunn effect. It is also shown that the combined action of a temperature gradient and an external magnetic field can facilitate the de sign and optimization of high-frequency devices and amplifiers.
This paper presents the results of a comprehensive investigation of the structural, phase, and mechanical properties of plasma electrolytic oxidation (PEO) coatings formed on the surface of EN AC-45000 (AlSi6Cu4) aluminium–silicon alloy in an electrolyte containing Al2O3 and SiO2 nanoparticles. The aim of the study was to determine the effect of electrolyte nanomodification on the morphology, phase composition, and microhardness of PEO coatings. The PEO process was carried out in a NaOH-based aqueous electrolyte with the addition of aluminium and silicon oxide nanoparticles. The microstructure and morphology of the coatings were investigated using optical and scanning electron microscopy. The elemental and phase compo sition was determined by energy-dispersive analysis and X-ray diffraction. The mechanical properties were evaluated by measuring the microhardness using the Vickers method, while the tribological performance was assessed using the ball-on-disk method under dry sliding conditions. The results showed that a two-layer ox ide coating was formed on the alloy surface, consisting of a dense inner α-Al2O3 barrier layer and a porous outer layer predominantly composed of γ-Al2O3. The incorporation of nanoparticles contributed to coating densification, reduced porosity, and promoted a more uniform distribution of micro-arc discharges. After PEO treatment, the surface microhardness increased from 65–80 HV to approximately 245–250 HV, repre senting more than a threefold increase. The coatings also exhibited a stable tribological response, character ized by a higher yet stable coefficient of friction and improved wear resistance compared to the untreated al loy. These results demonstrate the high potential of nanomodified PEO for enhancing the operational perfor mance of aluminium–silicon alloys.
This article presents the results of prototyping and designing a device for measuring the basic characteristics of solar panels (photocurrent and voltage) and climatic conditions (temperature and illumination). This device is being developed to identify potential faults in the solar panel-microinverter system, as well as the causes of reduced efficiency in converting light energy into electrical energy. As a result of prototyping, a prototype of the measuring device was assembled using an Arduino Mega 2560 R3 with a W5100 Ethernet module. Cur rent is measured by an ACS712 sensor. Voltage is measured via a voltage divider connected to the microcon troller's analog-to-digital converter input. OPT4003 light and DS18B20 temperature sensors are used. The IoT device is assembled using a RAK3172 sensor module and INA228, OPT4003, and DS18B20 microcir cuits. A power module based on two IRFP460 field-effect transistors was developed to measure the solar panel's current-voltage characteristics. Software has been written for the developed prototype and the IoT de vice.
The Dnestrovskii functions provide a powerful framework for understanding wave propagation, attenuation and instabilities in plasmas where relativistic effects dominate, as relativistic plasma dispersion functions. To calculate the Dnestrovskii functions for a wide range of parameter values, effective analytical and downward recurrence formulae are proposed in this study. These formulae allow users to make efficient calculations specific to high-energy or relativistic plasmas. Because the recurrence formulas are simple, calculating time and accuracy are improved, and the formulas are easy to use. The results obtained using the new analytical and downward recurrence formulae agree well with published results and those obtained using numerical cal culation methods for a wide range of parameters.
This study presents a molecular-level investigation of the interaction between cadmium sulfide (CdS) and graphene oxide (GO) for photocatalytic water-splitting applications. Density functional theory (DFT) calculations were carried out using the LC-omega PBE functional and LANL2DZ basis set in the implicit water model (IEFPCM) to optimize the geometry and study the interface properties. The optimized CdS structure exhibits a stable tetrahedral Cd-S configuration, whereas the CdS-GO composite exhibits strong interfacial bonding through Cd-O and S-O interactions supported by charge redistribution across the interface. Reduction density gradient (RDG) and non-covalent interaction (NCI) analyses reveal the presence of significant weak interactions, including van der Waals forces, hydrogen bonding, and Cd-O coordination, which stabilize the composite. The visualization of the blue regions in the NCI and RDG plots indicates attractive non-covalent forces that strengthen electronic coupling and charge transfer between CdS and GO. These results confirm that GO acts as an efficient electron acceptor, suppresses the recombination of photogenerated carriers, and enhances photocatalytic efficiency. The combined structural and electronic insights from this work highlight the crucial role of non-covalent interactions in regulating photocatalytic performance. The results of the study provide valuable theoretical guidance for the design of stable and efficient CdS-GO-based nanostructures for sustainable hydrogen energy production via solar-powered water splitting.
In this study, a novel perovskite-type oxide SrFe0.6Cu0.3Mo0.1O3-delta was synthesized via a conventional solidstate reaction route and comprehensively characterized using neutron powder diffraction (NPD), scanning electron microscopy (SEM), and thermal analysis. The application of NPD enabled precise determination of the atomic structure and differentiation between cations with similar atomic numbers. Rietveld refinement of the NPD data confirmed the formation of a single-phase cubic perovskite with the space group Pm-3m (no. 221) and a lattice parameter of a = b = c = 3.8997(1) & Aring;. SEM images revealed a highly porous, intercon-nected microstructure with uniform elemental distribution, while thermogravimetric analysis (TGA) demonstrated a two-step oxygen loss up to 1000 degrees C, confirming excellent thermal stability. The oxide exhibited a low thermal conductivity of 1.986 W & centerdot;m-1 & centerdot;K-1 at 900 degrees C, attributed to enhanced phonon scattering induced by Cu and Mo co-doping and lattice disorder. These findings indicate that controlled B-site co-doping can effectively tailor defect chemistry and phonon transport, resulting in materials with reduced thermal conductivity and improved structural integrity. Therefore, SrFe0.6Cu0.3Mo0.1O3-delta shows great potential for high-temperature energy conversion applications, including thermoelectric devices and solid oxide fuel cells.
Isothermal diffusion and convective mixing in a ternary He-Ar-N2 mixture at varying pressures and initial compositions were examined experimentally by means of the two-flask method. The study was conducted under strictly controlled laboratory conditions to ensure precise, comparable, and reproducible results across all experiments. It was found that when the density decreases with height, the mechanical equilibrium of the mixture can be disturbed, causing gravitational flows and partial convection within the system. Anomalous transfer of the component with the greatest molecular mass was detected at particular pressures and starting compositions, pointing to the influence of supplementary convective processes beyond ordinary diffusion. When the experimental results were plotted in the phase space of the three variables - pressure, initial composition, and diffused component concentration - a pronounced wave-like iso-concentration surface emerged. This surface appeared in regions corresponding to well-developed convective flows. Its formation correlated with the highest intensity of partial component mixing, highlighting the combined influence of pressure, composition, and gravitational effects on the mixture's dynamic equilibrium. These findings provide insight into the interplay between diffusion and convection in multicomponent gas systems, revealing conditions under which gravitationally induced flows significantly alter component transport and overall mixture behavior.
The article presents the application of concepts and methods of non-standard analysis to problems of theoretical electrical engineering. It is substantiated that standard methods of electrical engineering are not effective enough, because they are excessively complex or even unsuitable for calculating DC electrical circuits containing ideal inductances and capacitances. This problem arises because for direct current (with zero frequency) the inductive resistance is zero, and the capacitive resistance goes to infinity. As a result, when using standard methods to calculate such electrical circuits, it is necessary to solve uncertainty expressions of the type 0/0 or infinity/infinity , which creates difficulties within the framework of traditional mathematical analysis. Given the above difficulties, it is proposed to replace the classical mathematical analysis with a non-standard one. In this approach, the frequency of the direct current is considered not as zero, but as an infinitely small value alpha. This approach makes it possible to determine the reactance of inductive elements as alpha L and the reactance of capacitive elements as-1/alpha C . This allows to successfully apply all standard methods of theoretical electrical engineering and avoid the need to work with indefinite expressions. The article provides specific examples of the analysis of complex direct current circuits with ideal inductances and capacitances.
Titanium and its alloys are widely used in biomedical implants due to their favorable mechanical properties and corrosion resistance; however, their natural surface lacks sufficient bioactivity. Micro-arc oxidation is a promising approach to producing bioactive coatings, and the incorporation of nanoparticles such as TiO2 may further improve their functionality. This study aimed to determine the optimal TiO2 nanoparticle concentration in the micro-arc oxidation electrolyte that ensures coating stability and biological safety. Calcium-phosphate coatings were fabricated on commercially pure titanium using micro-arc oxidation with two TiO2 concentrations: 0.5 wt.% (MAO 1) and 1 wt.% (MAO 2). Surface morphology, porosity, and phase composition were analyzed by scanning electron microscopy, energy-dispersive spectroscopy, and X-ray diffraction. Corrosion resistance was evaluated via potentiodynamic polarization in NaCl and Ringer's solutions, while biocompatibility was assessed in vitro using HOS human osteosarcoma cells and MTT assays. Increasing the TiO2 content to 1 % decreased coating porosity (13.7 % vs. 26.3 % for MAO 1), enhanced corrosion protection, and reduced the friction coefficient compared to bare titanium. However, MAO 2 exhibited high cytotoxicity (81 % cell death) and partial structural degradation in the biological medium. MAO 1 maintained integrity and showed no toxic effects (3 % cell death). These results suggest that 0.5 % TiO2 is the optimal concentration, providing a balance between corrosion resistance, mechanical stability, and biocompatibility, supporting the development of safer implant coatings.
The article presents the results of research into the structure and tribological testing of WC-Co detonation coatings with a barrel filling volume of 64 % and 74 %. X-ray diffraction analysis of the WC-Co coating re vealed that undesirable Co and W2C peaks disappear after detonation spraying. Morphological analysis showed that with 64 % and 74 % detonation barrel filling, the coatings had a dense structure with a thickness of 136 μm and 161 μm, respectively. EDS mapping showed a uniform distribution of elements. Tribological tests of the coating revealed that the friction coefficient of the samples ranged from 0.48 to 0.53 for 74 % and 0.55–0.57 for 64 %. Based on the results obtained, the optimal technological regime for obtaining wear resistant WC-Co coatings by detonation spraying was established.
Академик Е. А. Бөкетов атындағы Қарағанды ұлттық университетінің физика факультетінің негізін қалаушылардың бірі, «Қарағанды университетінің хабаршысы. Физика сериясы» журналының алғашқы санынан бастап көп жылдар бойы редакция алқасының мүшесі болып қызмет еткен, физика-математика ғылымдарының докторы, профессор, ҚарМУ-дің Құрметті профессоры және Қазақстан Республикасының білім беру саласындағы Құрметті қызметкері Ақылбек Жүрсінұлы Тұрмұхамбетов сексеннің сеңгіріне аяқ басып отыр.
This article examines the influence of unintentional Cr3+ and Fe3+ impurity ions on the luminescent properties of Gd3Ga5O12 (GGG) single crystals. The characteristic features of the spectra excited by high-energy syn chrotron radiation in the temperature range of 10–300 K are analyzed. It is shown that at 10 K the lumines cence is dominated by a narrow-band emission of Cr3+ ions arising from the spin-forbidden 2E→4A2 transi tion, which indicates weak electron–phonon coupling and high crystalline homogeneity. It is revealed that with increasing temperature the intensity of this transition decreases significantly, while a broadband lumi nescence emerges, associated with the spin-allowed 4T2→4A2 transition and the contribution of Fe3+ ion emis sion. The temperature evolution of the spectra is shown to result from thermal redistribution of the Cr3+ excit ed-state populations, interlevel state mixing, and partial removal of the spin-forbidden nature of Fe3+ transi tions due to lattice vibrations. Based on the study, conclusions are drawn regarding the role of impurity cen ters in energy transfer and nonradiative relaxation processes. The results are of interest both for fundamental photonics and for the development of efficient luminescent materials and optical devices designed to operate over a wide temperature range.
The article presents the results of analyzing the energy spectrum and spatial distribution of neutrons in the core of the WWR-SM (Water-Water Reactor, Serially Modernized) research reactor after switching to low enriched fuel (19.75 % 235U). The increase in the number of fuel assemblies (FAs) from 18 to 24 altered the neutron characteristics of the reactor. A combination of computational methods (IRT-2D and WIMS codes) and experimental data obtained from neutron activation analysis enabled a detailed study of flux distribution. Fast neutrons dominate in the central part of the core, while the proportion of thermal neutrons increases sig nificantly in the beryllium reflectors. Measurements showed that in vertical channels, the thermal neutron flux density is 2.3 times higher than that of fast neutrons. In horizontal experimental channels, values up to 1.8·1012 neutrons/(cm2·s) with a cadmium ratio of 28 were recorded, confirming their suitability for research. Analysis of the thermal power of FAs revealed its maximum values in the center of the core with a gradual decrease toward the periphery, correlating with the 235U burnup distribution. The obtained results have practi cal significance for optimizing fuel loading, planning refueling campaigns, and testing prospective fuel com positions (UO2+Al, U3Si2+Al). The study emphasizes the need for further verification of computational mod els and more detailed investigation of neutron spectra under various core configurations. The presented data contribute to enhancing the efficiency and safety of WWR-SM reactor operation while expanding its research potential in nuclear physics and materials science.
