This study investigates the influence of electrolytic cell parameters on the electrolyte boiling rate during electrolytic plasma processing, a critical stage for plasma formation and subsequent surface modification. Focusing on a coaxial cell configuration with a conical anode and cylindrical cathode, this research employs analytical calculations based on the solution of the Laplace equation in spherical coordinates, validated by numerical simulations using the finite element method (Elcut 6.6), to predict electrolyte boiling times. These results are compared with experimental data, demonstrating good agreement, particularly at higher voltages (−200 V). The analysis reveals that while a simplified model provides a reasonable first approximation, it deviates at lower voltages (−50 V) due to the increasing importance of heat removal, neglected in the model construction. This discrepancy underscores the need for more sophisticated models accounting for non-uniform current distribution and heat transfer effects in complex cell geometries. The findings contribute to a deeper understanding of cathodic electrolytic plasma processing (EPP) dynamics and provide a foundation for optimizing cell design and process parameters for industrial applications such as diffusion saturation of steel components.

This study investigates the effects of electron beam irradiation on the mechanical and tribological properties of polyetheretherketone (PEEK), with particular focus on modifications resulting from the application of Litol-24 lubricant. Samples of pre-treated PEEK were irradiated at doses of 100,...

This study investigates the effect of electrolytic-plasma hardening time on the microstructure formation, hardness distribution, and corrosion behavior of grade 45 structural steel. The treatment was performed in a 15% aqueous sodium carbonate (Na₂CO₃) solution at an applied voltage of 300 V for different holding times (8, 10, and 12 s). Scanning electron microscopy and X-ray diffraction analyses revealed that increasing the EPH duration promotes the formation of a more uniform martensitic layer and reduces the amount of residual cementite. Microhardness measurements showed an increase in surface hardness from 190 HV for the untreated steel to 770 HV after the longest treatment. The cross-sectional hardness profile indicated the presence of a thin decarburized sublayer and a zone of maximum hardness corresponding to the martensitic structure. Potentiodynamic polarization tests in a 0.5 M NaCl solution showed a slight increase in corrosion current density after treatment; however, the corrosion rate remained within the range of 0.19–0.45 mm year⁻¹, confirming the satisfactory corrosion resistance of the hardened layer. The results demonstrate that controlling the EPH duration allows for optimizing the balance between enhanced hardness and maintained corrosion resistance of grade 45 steel.

This study investigates the influence of current density distribution on the hardening behavior of 20GL cast steel during electrolytic plasma processing (EPP). Experimental and numerical methods were combined to establish the relationship between discharge dynamics, heat flux, microstructural transformation. Electrolytic plasma hardening was carried out at cathodic voltages of 150 V and 250 V in a 20% Na₂CO₃ solution. The transient evolution of current density was analyzed using a 3D COMSOL Multiphysics model incorporating a vapor–gas shell (VGS) represented as a distributed impedance layer with realistic conductivity and permittivity. High-speed video confirmed that microdischarges preferentially initiate at sample corners, where modeling also predicts local current concentration and heat flux up to 12 MW/m². Experimental current density values (3–4 × 10⁴ A/m²) showed good agreement with the simulations. Microhardness tests revealed that increasing voltage from 150 V to 250 V increases the thickness of the hardened layer (from ~250 µm to ~600 µm) and raises surface hardness (up to 750 HV), while polarization tests showed a 40% reduction in corrosion rate. The results highlight that current density distribution governs the non-uniformity of thermal effects and surface strengthening during EPP, emphasizing the importance of electrode alignment and VGS stability for uniform hardening.

This article describes the design of a centrifuge for the separation of fat from meat–bone slurry to produce fat-extracted animal feed. The characteristics of the main components of the equipment and the principle of its operation were presented. The productivity of the centrifuge depending on duration and speed of rotation was determined. Data were provided for different drum speeds (1000, 1500, 2000, 2500 rpm) and centrifugation durations (5, 7, 10 and 15 min), with the yield (output) of defatted slurry measured as a percentage. Among the various conditions tested, the maximum yield of slurry was observed when the drum was rotated at 2000 rpm for 5 min, with a yield of 68.97%, while the lowest yield was observed when the drum was rotated at 1000 rpm for 15 min, with a yield of 55%. On the basis of modeling, a physical model including centrifugal separation with simultaneous centrifugal filtration was presented in the form of a system of differential, algebraic, and criterion equations.

The problems of sustainable development and management of the region's ecology on the basis of its economic and mathematical models are studied. As an example, the issues of sustainable development and environmental management of the oil regions are considered. To develop models of sustainable development and management of the region's ecology, the principle of a program-target approach is used. The possibility of taking into account the reaction of the ecological-socio-economic system to all factors with the help of economic-mathematical models, as well as the development of a program for the sustainable development of the region using such models, is substantiated. To assess the state of the ecological, social and economic system, the factors of management, economic development, as well as factors of technological and institutional development are considered. A model of a causal relationship between the ecological-socio-economic system of the region and a group of external development factors is proposed and described. Based on the proposed conceptual model using the method of adaptive balance of causes, a mathematical model of the ecological-socio-economic system has been developed. The developed mathematical model makes it possible to determine the reactions of the ecological-socio-economic system to external factors and predict the development scenario of the ecological-socio-economic system based on the forecast of changes in external factors.