Technical Physics最新文献

NiO and Cu:NiO powder prepared by sol-gel method and solution treatment was spin-coated on CdTe layer to form Cu:NiO back contact of CdTe solar cell. The performances of the solar cell with CdS/CdTe/Cu:NiO structure were simulated and analyzed using AMPS software. Through the simulations, we investigated the effect of the back contact layer thickness and carrier concentration on the solar cell performances. The maximum efficiency of 19.26% was obtained at the back contact layer thickness of 20 nm and carrier concentration of 10¹⁸ cm^–3. And we carried out the measurement of the recombination resistance and solar cell performances with different copper doping concentration for Cu:NiO back contact. The maximum efficiency was obtained at 5% copper doping concentration.

The results of silicon–carbon coatings deposition on an aluminum substrate, imitating a groove, by electron beam evaporation of silicon carbide are presented. The distribution of the thickness, composition, morphology, and hardness of the coating over the substrate sections was measured. An analytical model is proposed that makes it possible to calculate the deposition rate depending on the coordinate of the substrate site. The calculated and experimental results, presented in relative units, show a satisfactory agreement.

The plant operation simulation system is a device that analyzes the operating dynamics of the plant and supports the operator to conduct operational training in the same environment as the actual situation of the plant. With the rapid development of computer science and technology, various types of plant operation simulation systems have been developed worldwide, used for control system design, operator training, and development of operating procedures, and recently, advanced scientific and technological achievements have been introduced to further improve the performance of process simulators and expand their application range. This paper presents a methodology for real-time modeling of the dynamics of a single-phase fluid flow network, which is a large part of the plant thermal system configuration, and, this basis, aims to perform operational simulations of auxiliary systems of the plant.

In present paper analysis, we try to figure out first two mode of vibration of a non-homogeneous orthotropic rectangular plate with linearly varying temperature and circularly varying thickness in two dimensions. For non-homogeneity of the plate material the density vary linearly in x-direction. Rayleigh–Ritz method is used to solve the general differential equation of the orthotropic rectangular plate which is circular in two dimensions. The governing equations provide the frequencies for the first two vibration modes. Under clamped boundary condition several parameters including taper constants, thermal gradient, non-homogeneity, and aspect ratio, are analyzed. All calculations are calculated with the help of MATLAB, and the results are presented through graphs and tables for first two modes of vibration.

Hydrogen contained in the gas mixture of transversely excited atmospheric-pressure (TEA) CO₂ lasers plays an attractive role in improving the discharge stability and output characteristics of glow discharge by suppressing arc discharge. During the excitation of TEA CO₂ lasers, hydrogen effectively relaxes the CO₂ (010) level, with the action of inhibiting the O₂ production by dissociating CO₂ molecules, thus reducing the “bottleneck” in the operation of laser systems. We propose a new method that takes into account the role of hydrogen in the whole process from pumping to output of TEA CO₂ lasers. We numerically evaluate the transition from glow to arc discharge in the discharge gap of TEA CO₂ lasers. The current and voltage (V–I) differential equations of the pumping circuit in TEA CO₂ lasers using corona pre-ionization are solved to determine the O₂ concentration produced by the change in electron density. Then, the six-temperature model is combined to simulate the dynamics of high-power TEA CO₂ lasers considering the change in gas mixtures with hydrogen. The determined discharge voltage and gas mixture are essential for designing and operating TEA CO₂ lasers for suitable applications.

First mirrors are critical components of optical diagnostic systems for measuring parameters of thermonuclear plasma in tokamaks. The condition and surface quality of first mirrors affect the accuracy of measured data, such as plasma density, temperature, magnetic field magnitude and others. This work investigates the mechanism leading to catastrophic surface destruction of molybdenum and tantalum mirrors used in POINT diagnostic system of EAST tokamak. The destruction of molybdenum and tantalum mirrors—which are transition metals, along with tungsten—is visually observable due to the high reflectivity of their surfaces, initially polished to achieve the required reflective properties. This makes first mirrors a convenient tool for studying surface destruction processes of all transition metals used as the first wall of tokamaks. Thus, in this work, first mirrors with polished surfaces are considered as elements of the first wall of fusion reactors, prepared for detailed study of erosion processes resulting from exposure to thermonuclear plasma. It is noted that it is precisely the mirror surface that allows visual observation of the catastrophic nature of the destruction of molybdenum and tantalum surfaces. Surface studies based on optical microscopy have revealed predominant destruction of surface structures along intergranular spaces and in regions of point defects arising from plasma exposure. X-ray photoelectron spectroscopy made it possible to establish the effect of the return to the first-wall surface of positively charged molybdenum ions and molybdenum-containing radicals. This work presents a destruction mechanism for transition metals that follows from the presented experimental facts. The study emphasizes that catastrophic plasma-chemical destruction occurs with all tokamak components made of transition metals that face the plasma.

This study investigates the thermal–hydraulic behavior of the Warm Water Layer (WWL) system behavior of the Warm Water Layer (WWL) system in the RSG-GAS research reactor using CFD simulations based on actual operating data from five core configurations (Cores 101, 102, 103, 107, and 108). The focus is on how inlet temperature, flow rate, and outlet distribution affect thermal stratification and its interaction with the primary coolant. To better understand the observed flow behavior, a net flow parameter (NET) is introduced, defined as the difference between inlet and outlet flow rates. Rather than treating stratification only from temperature profiles, NET is used here to directly relate flow imbalance with mixing and penetration behavior. The results indicate that stable stratification is consistently obtained at an inlet condition of 60°C and 10 m³/h. Increasing the inlet flow rate generally strengthens the layer and improves stratification, but at the same time enhances turbulent mixing with the primary coolant. At lower flow rates, upward penetration becomes weaker, mainly due to stronger downward entrainment linked to higher NET values. Higher inlet temperatures further support vertical temperature separation, although local heat transfer also becomes more active. Overall, the results show that WWL performance is not controlled by a single parameter, but by the balance between stratification and mixing. In this context, NET provides a simple but practical way to interpret the behavior and can be used to evaluate WWL operation under realistic conditions.

EPDM/NBR elastomer blends reinforced with silane-treated graphene oxide were successfully fabricated to enhance their overall performance. Graphene oxide (GO) was synthesized using a modified Hummers oxidation route and subsequently chemically functionalized with γ-aminopropyltriethoxysilane (KH550) to strengthen its compatibility with the rubber matrix. This chemical modification significantly improved the distribution of the nanofiller within the elastomeric system relative to unmodified graphene oxide, resulting in more effective stress transfer between the filler and polymer phases. As a result, the composites containing functionalized graphene oxide demonstrated notable improvements in mechanical behavior. At an optimized filler concentration of 5 phr, the tensile strength, stress at 100% elongation, and tear resistance increased by 36.2, 19.4, and 57.1%, respectively. Furthermore, these reinforced materials exhibited superior resistance to abrasive wear compared with both unfilled blends and those containing untreated graphene oxide. The enhanced performance is primarily associated with uniform nanofiller dispersion and stronger interfacial interactions established through silane functionalization. Overall, the incorporation of KH550-modified graphene oxide (KH550-GO) represents a promising and practical approach for producing advanced elastomeric materials with improved durability and mechanical integrity for demanding engineering applications such as automotive components and sealing technologies.

The paper considers the features of three-dimensional modeling of the thermal state of rotary piston engine (RPE) components in Ansys Fluent software. It is shown that a well-developed computational and experimental basis has been established for internal combustion piston engines (ICEs), whereas no unified methodology currently exists for RPEs that accounts for rotor motion and the nonuniform nature of heat transfer. A transient CFD modeling methodology is proposed using user-defined functions, a dynamic computational mesh, the Realizable k–ε turbulence model, the Finite Rate/Eddy Dissipation combustion model, and conjugate heat transfer between the gas, solid, and liquid domains. The methodology provides the pressure, temperature, and gas velocity fields, as well as temperature fields of engine components. Validation against experimental pressure and temperature data confirms the applicability of the proposed approach for engineering assessment of the thermal state and subsequent strength calculations.

Background. The article proposes a method for forming a structured thermal representation of a brushless DC (BLDC) motor based on analysis of infrared thermograms in three‑dimensional red-green-blue (RGB) space. The relevance of the study is due to the need to increase the reliability of monitoring the technical condition of BLDC engines, which are widely used in the designs of unmanned aerial vehicles. Materials and methods. The paper implements a synthesis of computer vision and statistical analysis methods: clustering of color patterns of thermograms is performed using the KDE and Mean Shift algorithms. Based on the selected clusters, the key color moments are calculated, which make it possible to quantify the thermal state of the critical zones of the engine. Results and conclusions. A methodological scheme for the analysis of thermograms has been developed, including the decomposition of the engine into thermal zones according to the spatial and color criterion and the calculation of color moments as compact numerical features.