The collection of scientific works covers the results of experimental and theoretical research in scientific specialties: 105 Applied physics and nanomaterials; 113 Applied Mathematics; 131 Applied Mechanics; 132 Materials Science; 133 Industrial engineering; 151 Automation and computer-integrated technologies.
Луцький національний технічний університет
STUDY OF HYDRO-GAS-DYNAMIC PROCESSES IN CLOSED BYPASS CHANNELS WITH CIRCULAR AND TRIANGULAR CROSS-SECTIONS
iangular cross-sections. One of the approaches used was the analytical method, which involved complex mathematical calculations followed by process visualization using the MATLAB system. This approach enabled a detailed investigation of the channel characteristics and the reproduction of laminar flow phenomena of liquids and gases, allowing for a deeper understanding of their physical features. Another method involved the use of simulation-based computer modeling of the laminar flow of liquid and gas through channels with circular and triangular cross-sections using SOLIDWORKS Flow Simulation software. To implement this approach, the necessary input parameters and conditions were specified, and the resulting data were subjected to detailed analysis and interpretation. This method allowed for the creation of highly accurate computer models of hydrogasodynamic processes, facilitating a deeper exploration of their behavior and interaction under various cross-sectional shapes of the channels. A comparison of the results obtained from both methods confirmed their ability to adequately model hydrogasodynamic processes in closed bypass channels with circular and triangular cross-sections. The data obtained not only validated the accuracy of the chosen methods but also provided a deeper understanding of the mechanisms of liquid and gas flow under laminar conditions. This research opens new opportunities for further scientific developments in the field of hydrogasodynamics and has the potential for application in engineering calculations where high precision, reliability, and credibility of hydrogasodynamic models are crucial.
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SYNTHESIS OF NITROSTARCH: CORRELATION BETWEEN NITRATION METHODOLOGY, STRUCTURAL CHARACTERISTICS, AND FUNCTIONAL PROPERTIES IN THE CONTEXT OF DEVELOPING HIGH-ENERGETIC MATERIALS
This study presents a comprehensive investigation into the synthesis of nitrostarch, focusing on the correlation between nitration methodology, the resulting structural characteristics, and the functional properties critical for its application in highenergy materials. A comparative analysis of classical nitration methods using mixed acid (HNO₃/H₂SO₄) and a modern approach employing nitrating oleum (with a free NO₂ content of 3-20%) in combination with sulfuric acid was conducted. The research highlights the significant influence of the nitrating agent's composition on the degree of esterification, molecular degradation, and ultimately, the thermal stability of the final product. Experimental work involved the nitration of corn and potato starch under controlled conditions. The oleum-based method was found to be superior, enabling the production of nitrostarch with a high nitrogen content (12.6-12.9%), indicative of a high degree of substitution, while minimizing destructive side reactions and preserving the integrity of the polymer chain. Furthermore, the impact of various post-synthesis stabilization techniques, including acid boil, alkaline boil, and washing procedures, was systematically evaluated. The results demonstrate the strong structure-property relationships in nitrostarch and confirm its significant potential as a sustainable and effective component for modifying the burning rate and mechanical properties of advanced high-energetic compositions, thereby contributing to the diversification of raw material sources for the defense and aerospace industries.
METHODOLOGY FOR PREDICTING FLAX FIBER AND SEED YIELDS USING UAV PHOTOGRAPHY AND AUTOMATED PHOTOANALYSIS
Accurate forecasting of flax (Linum usitatissimum) fiber and seed yields is essential for optimizing harvest operations and post-harvest processing. This paper presents a methodology that integrates high-resolution UAV (drone) imagery with field observations of crop maturity and growth quality to predict final fiber and seed yields. A multi-rotor UAV equipped with multispectral and RGB sensors captured images at key growth stages. These images were automatically processed using a custom image-analysis module to compute vegetation indices (e.g., NDVI) and structural plant traits. The proposed method provides timely and precise yield assessments, supporting efficient flax production and sustainable utilization of agricultural biomass.
GENERATIVE ARTIFICIAL INTELLIGENCE AGENTIC SOLUTIONS FOR SOFTWARE QUALITY ASSURANCE
AI agents demonstrate autonomy in planning, execution, analysis, and maintenance, offering potential to address persistent challenges in quality assurance such as maintenance overhead, lengthy debugging cycles, and limited predictive capacity. To structure the investigation, seven core agentic use cases were defined, covering the full lifecycle of test automation. A comparative evaluation of three SaaS platforms—KaneAI, Zephyr Scale Automate, and TestRigor—was conducted using a dual framework that combines quantitative scoring with qualitative assessment. This approach enables an integrated understanding of both the maturity of support for agentic functionality and the qualitative depth of its implementation, contributing to ongoing discourse on the evolution of software testing practices.
EXPLOSION AND FIRE HAZARD ANALYSIS OF NATURAL GAS EXTRACTION
The article emphasizes that the problem of securing gas production is relevant and requires the implementation of modern protection technologies. The formation of an explosive and fire-hazardous environment in a drilling rig is analyzed. It is noted that the Safety Rules in the Oil and Gas Industry indicate only the categorization of premises, and there is no information about the categorization of external installations. It is established that the specified external installations belong to categories Az (explosive and fire-hazardous) and Vz (fire-hazardous). It is proposed to make changes to the Safety Rules in the Oil and Gas Industry on the need to categorize external installations, and at natural gas production facilities to determine categories for explosion and fire hazard for gas wells, drilling rigs, mobile compressor stations, flare systems and other facilities related to the operation of gas production facilities.
TECHNOLOGICAL ASPECTS OF IMPROVING THE EFFICIENCY OF MANUFACTURING ROASTED AND GRATED SEMI-FINISHED PRODUCTS FROM ONIONS
The paper presents the research results on the technological process and justification of measures taken to improve the production line for roasted and grated semi-finished products from onions. Analysis of the operation of this line at the Cherkasy production unit of the limited liability company “Vidzi Production” of the “Veres” group of companies revealed a number of significant shortcomings in its operation. Based on the results of the analysis, an improved line with significantly enhanced technical characteristics was substantiated, developed, and implemented. The improvement in characteristics was achieved through the introduction of more efficient roasting ovens, root cutting machines, and cleaning machines.
COMPLEX SOLUTION OF THE PROBLEM OF REMOVING CONTAMINATION FROM THE WASHING LIQUID OF TECHNOLOGICAL DEVICES USED FOR INDUSTRIAL CLEANING OF BEARINGS
The article considers the problem of cleaning rolling bearings by removing various types of contaminants from the working surfaces and rolling paths, and the contaminated cleaning fluid used in the process. The solution of which is proposed through the research and use of combined cleaning systems combining physico-chemical and mechanical methods of filtering the washing liquid, adapted to the specifics of the removed contaminants. The use of an original design of a device for cleaning miniature ball bearings with combined pulse-magnetic and ultrasonic fields is proposed. The device is equipped with a sophisticated filtering system of the washing liquid. Based on the results of the research, the washed pollution of various physical nature was analyzed. Recommendations are proposed for the use of combined operations of cleaning rolling bearings with ultrasonic and pulse-magnetic fields as finishing ones to increase their durability and operational reliability.
contamination of various physical nature
FEATURES OF THE KINETICS OF DRYING SOLID WASTE FROM POULTRY FARMS AS A BASIS FOR IMPROVING THE PRODUCTION SCHEME OF ORGANIC FERTILIZERS
The article presents the results of experimental studies of the kinetics of drying solid waste from poultry farms. The initial average moisture content of the material and the structure of the moisture-chicken manure bond were determined. Conditions for constant and decreasing drying rates were identified. Based on the analysis of the data obtained, improvements to the technological scheme of the machine and equipment for the chicken manure disposal plant were proposed, resulting in the production of high-quality organic fertilizer.
DEVELOPMENT OF A DEVICE FOR INCLINING FLAX STALK FOR A FLAXPULLING APPARATUS
The article describes the design of a device for inclining flax stalk for a disc-belt flax-pulling apparatus. An experimental setup with a device for inclining flax stalk was manufactured and its performance was tested in field conditions. It was established that the use of the device for inclining ensures a guaranteed tilt of the stalks, which are brought by dividers to the pulling streams, thereby reducing the stretching and skewing of the stalks in the belt. It also ensures the perpendicularity of the flax stalks clamped in the of the pulling stream, thus improving the performance of subsequent technological operations of the flax harvesting machine. Such as combing seed capsules and spreading flax straw.
GAME THEORY IN BUSINESS: MATHEMATICAL MODELS OF INTERACTION
The article is devoted to the analysis of the application of mathematical models of game theory in business for modeling the interaction of economic agents, with an emphasis on competitive strategies, the behavior of companies and consumers in a dynamic market environment. The obtained scientific results demonstrate that game theory effectively models the competitive behavior of firms, in particular through dominant strategies and Nash equilibria, allowing the prediction of the consequences of price wars and the breakdown of agreements, as in the classical prisoner’s dilemma. In modeling consumer behavior, the phenomenon of conspicuous consumption is highlighted, where payoff matrices of costs and benefits show how social effects influence choice, shaping zero-sum games and mixed strategies to minimize losses. In marketing decisions, illustrated by the example of the air conditioning systems market, payoff matrices with correction coefficients make it possible to determine optimal combinations of strategies, such as network expansion or advertising campaigns, taking into account the absence of saddle points and the transition to probabilistic profiles. The Cournot model illustrates the dynamics of a duopoly, where cooperative strategies provide higher profits, but competitive incentives lead to defection, emphasizing the need for coordination games for sustainable development. The practical value of the study lies in providing tools for business management, particularly for optimizing strategies in marketing, logistics, and pricing, which helps companies minimize risks under competition and increase profitability. The application of the proposed models allows forecasting the reactions of competitors and consumers, contributing to effective decision-making in real market situations such as retail trade or supply chains.
SELF-SYNCHRONIZATION OF VIBRATION EXCITERS OF VIBRATING MACHINES WITH BIHARMONIC OSCILLATIONS OF THE WORKING BODY
The practical possibility of self-synchronization of two pairs of unbalanced vibration exciters with multiple rotation frequencies is considered. The problem is solved using the integral criterion of stability of synchronous movements. Formulas for synchronizing moments are obtained; conditions for the existence and stability of synchronous modes of motion of exciters. Equations are given for determining the phase shift angles in possible synchronous modes of motion of vibration exciters. Practical recommendations are formulated regarding increasing the stability of multiple-synchronous rotation of vibration exciters. Theoretical results are consistent with the results of computer modeling
EXPERIMENTAL STUDIES ON THE PREPARATION OF FUNCTIONALLY ORIENTED SYNTHETIC DIAMOND POWDER
Experimental studies of synthetic diamond powder of the AC20 grade with a grain size of 100/80 have shown that the influence of the methods of modifying the original powder (modification by high-voltage electric discharges or liquid-phase oxidation) is reflected in the change in the adsorption-structural and morphometric characteristics of the powders: in particular, the specific surface area; specific pore volume; average pore radius; total pore volume, and the distribution of pore volume by their sizes. The specific surface area of the original samples tends to decrease after the modification of the powders. The studied samples have a developed mesoporous surface structure. The studied modification methods do not show a significant effect on the morphometric characteristics of the powders. Comparative analysis of the results by the coefficients of linear approximation of the pore size distribution curves allows us to obtain at the quantitative level the indicator (а2/а1) of the change in the state of the powder surface, which can serve as a characteristic of the quality of the powder surface when studying the defectivity of the surface of synthetic diamond grains and its influence on the operational characteristics of the diamond tool. The results obtained provide a basis for further development of a database for the formation of optimal indicators of the adsorption-structural characteristics of synthetic diamond powders of wide functional purpose.
METHOD FOR DETERMINING THE MAGNETIC FIELD STRENGTH IN A SHEET OF ELECTRICAL STEEL
This work is devoted to the determination of the periodic component of the magnetic field strength in a layer of electrical steel. When constructing a mathematical model, the magnetic permeability is approximated by a fractional-rational function. To calculate the properties of the magnetic field, it is proposed to use two nonlinear methods - the method of the fourth order of accuracy and the third order of accuracy with a two-sided estimate of the error of the result. The advantages of this approach are that using only four calculations of the right-hand side of the differential equation, a method of fourth-order accuracy, two two-sided approximations of third-order accuracy, and an explicit estimate of the main term of the local error of the result are obtained. The mathematical model was calculated and analyzed, and the form of the magnetic permeability approximation that should be used in the study of weak and strong fields was determined.
electrodynamic equations, magnetic field strength, initial value problem, continued fractions, two-sided approximations
SYNTHESIS MODES OF CONVERSION PLASMA-ELECTROLYTIC COATINGS ON ZIRCONIUM BASIS AND THEIR CORROSION PROPERTIES
The aim of the work was to conduct a spectral analysis of electrolytic plasma. It was established that the plasma temperature in which the high-temperature oxide is formed is 8000 500 K. The influence of the electrolyte composition and the ratio of current densities on the electrophysical parameters of plasma-electrolytic oxidation was investigated. During the research, a study of corrosion resistance in such an aggressive environment as 10% HCl was conducted. As a result of the experiments, it was found that the obtained oxide-ceramic coatings are characterized by high microhardness and corrosion resistance.
SURFACE PROPERTIES OF DIAMOND GRINDING POWDERS OF THE AC250 BRAND OF DIFFERENT GRAIN SIZES
The paper presents the results of the study of the surface properties of diamond grinding powders of the AC250 brand with grain sizes of 630/500 and 500/400 (according to the normative documentation of Ukraine). The study of the structural and sorption properties of the surface of the grinding powders was carried out by the volumetric method of nitrogen adsorptiondesorption according to the standard procedure. It is shown that despite the larger size of the diamond crystals, the sample with grain size of 630/500 has a larger specific surface area (0.21 and 0.18 m2/g, respectively) and a pore volume of 1.99 versus 1.75×10-4 ml/g, compared to the sample with grain size of 500/400. This result is due to the smaller average pore radius for the sample with grain size of 630/500, compared to the sample with grain size of 500/400. At the same time, the studied samples have a specific surface area approximately 50–70 times larger than the surface area of ideal diamond crystals of the corresponding grain size, and increased hydrophilicity, which is the result of the presence of point defects in the surface layer of the samples.
concentration of nitrogen-containing defects
OPTIMIZATION OF STIMULATED RAMAN SCATTERING MODELING IN SELFFOCUSING LIQUIDS
This study presents a numerical verification of the physical validity of using a quadratic dependence of the laser beam radius in modeling stimulated Raman scattering (SRS) in self-focusing media, such as toluene. The influence of various powerlaw dependencies of the gain coefficient on the beam radius (n = 1, n = 2, n = 3) is analyzed in terms of numerical stability and result accuracy. Two numerical approaches are developed: the Adams method with adaptive step size and the Euler iterative method with fixed step size, both based on energy conservation laws and the Kerr effect. The simulations are performed using parameters typical for toluene (initial beam radius of 113 μm, refractive index of 1.49, laser wavelength of 694.3 nm, and critical power of 25 kW). The results show that the quadratic model (n = 2) provides the optimal combination of stability and physical correctness, accurately capturing the Stokes generation threshold (zf ≈ 0.083 m) and power stabilization. The linear model (n = 1) underestimates the self-focusing effect, violating energy conservation, while the cubic model (n = 3) exhibits numerical instability. This work has practical significance for optimizing laser systems in spectroscopy, optoelectronics, and biomedicine. Moreover, an important aspect of developing numerical programs was to improve computational efficiency. Implementing the modeling in the form of standalone programs allows for a significant reduction in calculation time compared to manual analysis or the use of general-purpose software packages. This enables the investigation of complex nonlinear effects under realistic conditions with high spatial resolution
JUSTIFICATION OF THE DESIGN SCHEME OF AN ELECTRONIC TACHOMETER FOR A DIESEL ENGINE
The object of the study is diesel engine monitoring systems, crankshaft rotational speed, and an electronic tachometer. The problem addressed was to determine technical and technological solutions that improve the efficiency of diesel operation by justifying the design scheme of an electronic tachometer. Based on the research results, the design and operating principle of an experimental electronic tachometer for a diesel engine were substantiated. The tachometer was developed on the basis of the Arduino Uno R3 microcontroller, Hall effect sensor SS49E, and 1602 LCD module. The device is proposed as a complementary component of an experimental electronic fuel supply control system for a diesel engine equipped with a distributor-type fuel injection pump ND-21. A linear relationship was established between the readings of the developed electronic tachometer and the mechanical tachometer model TCh10-R (DSTU EN60051-2:2017), with a root mean square deviation of ±4.8 rpm. The discrepancy between the analog and digital tachometer readings did not exceed 2.5% over the entire measurement range (up to 1000 rpm). The electronic tachometer demonstrated a fast response time (~150 ms), which made it possible to track even short-term changes in rotational speed.
ANALYSIS OF WELDING TECHNOLOGIES FOR THE AUTOMOTIVE INDUSTRY
The article discusses modern welding methods in automotive engineering, in particular technologies such as arc welding (MMA, MIG/MAG, TIG), submerged arc welding, electroslag welding and plasma welding. An analysis of their technical characteristics, advantages and disadvantages, as well as the specifics of their application in the context of requirements for quality, reliability and economic efficiency of joints is carried out. It has been determined that the choice of the optimal welding technology depends on the material, design and purpose of the parts, and the introduction of innovative methods contributes to improving the quality and competitiveness of automotive products.
THE IMPACT OF DATA COMPRESSION ON THE EFFICIENCY OF DIRECT INTERACTION BETWEEN SERVICES IN A MICROSERVICE ARCHITECTURE
In modern microservice architectures, which are increasingly implemented in high-load, distributed environments with dynamic scalability, there is a growing interest in models of direct interaction between individual services without the use of traditional proxy solutions – so-called proxyless approaches. This interaction model reduces system response time, avoids delays caused by intermediary routing, optimizes infrastructure costs, decreases the number of potential points of failure, and ensures greater architectural flexibility, scalability, control over data flows, and compliance with cloud-native principles. In this context, the implementation of data compression algorithms becomes particularly important as one of the key means of optimizing information exchange between services. Compression significantly reduces the volume of transmitted data, lowers network load, minimizes request processing latency, and helps reduce resource consumption during intensive inter-service traffic. This paper provides a theoretical analysis of the impact of data compression on the quality, performance, and reliability of direct communication within a microservice architecture. The focus is on lossless algorithms such as GZIP and Snappy, which are among the most widely used in cloud-native environments supporting REST and gRPC. The analysis explores the specifics of their integration, the dependence of efficiency on data format and structure, the type of API requests (single or batch), as well as network latency levels and computational overhead. The advantages of GZIP are highlighted for high-load scenarios that require deep compression, while Snappy is preferred in cases with strict latency constraints and a priority on speed. Potential limitations related to service compatibility, CPU overhead, and configuration flexibility when managing compression parameters manually are also identified. The importance of configuration consistency on both ends of service interaction is emphasized, including proper header encoding and support for the required formats. The conclusion is drawn that an adaptive and context-aware approach to selecting a compression algorithm – considering the nature of the API, the structure of the load, the interaction topology, processing priorities, and network characteristics–is critically important to ensure stable, reliable, and efficient microservice operation within proxyless architectures of modern cloud and hybrid platforms.
EXPERIMENTAL RESEARCH OF GAS LASER CUTTING OF STAINLESS STEELS WITH HIGH-POWER LASER RADIATION
The main drawback of experimental studies of the technological process of gas laser cutting of stainless steels of various thicknesses is their sporadic nature and the lack of a unified approach to establishing the relationship between cutting modes and maximum process productivity with satisfactory cut quality. Therefore, this study examines the influence of the main factors of gas laser cutting, such as different ranges of workpiece thicknesses, variable conditions of laser beam focusing and defocusing, as well as the type and pressure of process gases on the optimal cutting speed of stainless steel sheets. As a result of such research, general recommendations have been formulated for selecting the optimal cutting modes for stainless steels using powerful 20 kW laser radiation for different ranges of workpiece thicknesses, taking into account various conditions for gas laser cutting, which significantly simplify the selection of the necessary modes for this type of processing.
THERMO-DEFORMATION LASER SINTERING OF DIAMOND-CONTAINING COMPOSITES FOR ABRASIVE MACHINING OF MACHINE-BUILDING PRODUCTS
The main drawback of existing technologies for producing diamond-containing abrasive tools is their low efficiency and the limited number of suitable binder materials for the working layer with filler. This is due to the maximum allowable heating temperatures of diamonds (up to 700–800 °C). The prolonged sintering process, unpredictable tool durability, increased diamond consumption, and high processing cost necessitate the development of new synthesis methods for composites with superhard materials (SHM). Therefore, this study explores a fundamentally new process of laser synthesis of diamond-containing composite materials for the production of abrasive tools. These tools can be used for grinding large-size sheet products made of carbon fiber, fiberglass, organoplastics, honeycomb panels, and other materials widely used in machine building. Synthetic diamonds AS125 (grain size 425/300) were used as abrasive grains, while the binder consisted of Ni-based powders (fraction 50 μm) with the addition of Co. Technological equipment equipped with a Maxphotonics 4th-generation fiber laser emitter (λ = 1.06 μm) was employed, along with a set of experimental methods of physical materials science. As a result of thermo-deformation laser sintering in an inert atmosphere (source power 500–1000 W, exposure time 0.18–0.36 s), a dense, defect-free diamond-containing layer was synthesized on the surface of a steel substrate. The addition of Co to the Ni-based binder enabled the formation of an extensive contact area with the diamonds and allowed for the analysis of the interfacial morphology between diamond and binder, depending on the irradiation conditions. The optimal laser processing parameters were determined, which ensure the formation of Cr₇C₃ carbide and improved wettability of the diamonds by the binder material.
SIMULATION MODELING OF LOSSES DUE TO DELAYED SOWING
The object of the study is the technological processes of growing agricultural crops, violations of sowing dates, and a simulation model for assessing possible losses due to untimely sowing. It is noted that each agricultural crop best realizes its biological potential when favorable conditions are created for its life activity. Violations of these conditions lead to a decrease in yield and, as a result, profit. In modern agricultural production technologies, emphasis is placed on strict adherence to recommendations for the timely performance of the prescribed technological operations. Simulation modeling has determined the possible losses due to untimely sowing of certain crops. Among early-sown crops, we will analyze peas, and among mid-season crops, corn. It has been established that losses from untimely sowing of peas with an average yield of 3.5 t/ha can be up to 30%, or in monetary terms, 8.14 thousand UAH/ha. For corn, losses from untimely sowing are modeled in the range of 0-30%. With an average corn yield of 5.0 t/ha, losses from untimely sowing amount to 10% – 4.8 thousand UAH/ha, 20% – 9.6 thousand UAH/ha, 30% – 14.4 thousand UAH/ha.
PHYSICS OF ASPECTS IN HYDRODYNAMIC PHENOMENA IN TECHNOLOGICAL PROCESSES
The article is devoted to the problems of the technological process described by physical laws, in particular, the phenomena of transfer yet energy of the flow of a non-stationary fluid. An attempt is made to describe the movement of a liquid in a confined space with the possibility of its transporting capacity, based on the Cholomew effect, i.e. the ability of certain particles in a liquid to undergo the phenomenon of surfacing. For example, such a phenomenon causes better cleaning of the bottom of a well (oil and gas or other) being constructed. The goal is to provide a description of the flow of a fluid capable, in a sufficiently closed space, due to certain phenomena and processes, of creating a turbulent flow of the technical fluid used, and thereby capable of ensuring the implementation of the corresponding technological processes necessary for technical fulfillment. One of these directions is to ensure stable rotational-transitional flow motion, which is achieved at certain values of the Froude number (Fr), which are different for liquids with different rheological properties. For example, the Reynolds number (Re) of a Newtonian fluid must have a value that is twice that of a non-Newtonian fluid with similar molecular composition. There is a functional relationship between such fluids, described by a parabolic relationship. Intuitively, based on accumulated experience, certain devices have been created that are capable of solving the problem mentioned above, but in science, an experiment must be confirmed by theory, and theory by experiment. Today, unfortunately, there are no methodological recommendations that would take into account, from the point of view of physics, the specifics of hydrodynamic processes for technologists, for example, during the construction of inclined and horizontal wells, with appropriate means and devices. And this is an important justification for creating the intended basic principles in this direction, the result of which is the correspondence and theoretical confirmation of axiomatic technological developments, which are possessed in significant quantities by employers in the oil and gas fields. In a first approximation, the goal is achieved by applying relations for continuous flow, which take into account the kinematic characteristics of the fluid.
ANALYSIS OF THE COMPLEX ELECTRICAL CONDUCTIVITY OF PORCINE LIVER TISSUE
In the present study, the frequency dependence of the electrical conductivity of porcine liver tissue subjected to different storage conditions—natural aging, cooling, heating, and γ-irradiation—was analyzed. To model the spectral characteristics, the generalized Cole–Cole model with two dispersions (α and β) and a direct current conductivity component was employed. Parameter optimization was performed using the differential evolution method. The results demonstrated that the model provides a high degree of agreement with the experimental data over a wide frequency range (0.01 Hz – 1 MHz). The smallest changes in electrical properties were observed in samples stored at +5 °C, while the most pronounced alterations occurred after heating and prolonged exposure to air. High values of the α parameter indicate a polydisperse nature of the relaxation processes in the studied tissues. The findings confirm the effectiveness of the Cole–Cole model for assessing structural changes in biological samples, opening up prospects for non-invasive diagnostics and biomedical applications.
INVESTIGATION OF THE OPERATIONAL CHARACTERISTICS OF TORQUE-FLOW PUMPS WITHIN THE OPERATING RANGE Q = 0.7–1.2 Qnom
This study presents a numerical investigation of the operational characteristics of the torque-flow pump TFP 80-32 within the flow rate range Q = 0.7–1.2·Qnom, which corresponds to typical conditions of long-term pump operation. Based on the geometric parameters of the pump, three-dimensional models were developed and a CFD analysis was carried out in ANSYS CFX using the k–ε turbulence model. Two types of impellers were considered: one with six curvilinear blades and a dual-tier impeller with twelve blades. The obtained characteristics demonstrated that, within the operating range, both designs provide a stable, gently declining head curve and comparable hydraulic efficiency values (up to 48.3% for the six-blade impeller and 47.5% for the dual-tier impeller). At the same time, the dual-tier configuration ensures an increase in head by 1.3–1.8 m (3–5%) without a significant decrease in energy efficiency. Analysis of velocity and pressure fields showed that the dual-tier impeller provides more uniform flow distribution onto the blades, reduces channel diffusivity, and decreases vortex losses in the free chamber. The results of the study justify the choice of impeller design depending on the operating conditions: the six-blade impeller is more suitable for regimes close to the nominal point, while the dual-tier impeller ensures an additional head margin and greater operational stability at higher flow rates.
STUDY OF DYNAMIC VISCOSITY OF EPOXY COMPOSITIONS USING NANO- AND MICRO-FILLERS
The article investigates the effect of nano- and micro-fillers on the dynamic viscosity of epoxy composites based on DER 331 resin. Carbon nanotubes (NT) and CARBON BLACK N220 nanosoot were used as nanofillers at a content of 0.01 to 0.1 mas.%, and chromium oxide Cr₂O₃ powders (20 μm) and silicon carbide SiC (40 μm) at a content of 5 to 20 wt.% as microfillers. Rheological studies were carried out on an NDJ-1S viscometer at four shear rates (6, 12, 30, 60 rpm). The results showed that the introduction of fillers increases the viscosity of composites compared to pure resin, with microfillers having a greater effect due to their higher volume fraction. Nanofillers significantly increase the viscosity of epoxy compositions than NTs due to their tendency to aggregation. All compositions exhibit pseudoplastic properties: viscosity decreases with increasing shear rate. The mechanism of changes in rheological properties is explained by the model of floc formation and destruction (for nanofillers) and hydrodynamic interaction of particles (for microfillers). The optimal filler content was established: 0.05 mas.% for nanoparticles and 10 mas.% for microparticles, which can provide an improvement in mechanical properties without significant deterioration in processability. The results obtained are of great importance for the development of technologies for applying protective coatings in shipbuilding.
PRODUCTION OF TUNGSTEN-BASED POWDER BY REDUCTION IN HYDROGEN
The article develops a method for obtaining tungsten-based powders by reduction in hydrogen. Technological characteristics of the synthesis are established, which allowed obtaining tungsten-based powders with specified physical and technological properties. Morphological features of the particles of the obtained powders, their chemical and phase composition, as well as bulk density and compaction density, and compressibility are established.
THERMODYNAMIC ANALYSIS OF OBTAINING BINARY Cr-Ta LIGATURE
Thermodynamic assessment and study of phase formation patterns in the Cr-Ta system during the simultaneous carbothermal reduction of Cr2O3 and Ta2O5 oxides with carbon at a temperature of 1000 ℃ were carried out. It is shown that in the presence of a reducing agent (carbon), thermal energy is directed to the reduction of Cr2O3 and Ta2O5 oxides. This prevents the reaction between the reduced metals and, as a result, limits the formation of stable Cr2Ta phases.It was established that the use of the adjacent reduction method not only contributes to the formation of a stable Cr-Ta solid solution, but also reduces the average particle size of the reduced powder to 2 μm.
HARDWARE PLATFORMS FOR AUTOMATED UAV CONTROL: COMPARATIVE ANALYSIS AND OPTIMAL SOLUTION SELECTION
This article examines the most optimal hardware platforms for controlling unmanned aerial vehicles (UAVs). It explores essential factors in selecting flight controllers, including computational performance, peripheral support, energy efficiency, and real-time operating system (RTOS) compatibility. Special emphasis is placed on power stability, integration with sensors, cameras, and communication modules, and ensuring seamless operation in challenging conditions. The suitability of ESP32, Teensy 4.1, and STM32 «Blue Pill» for advanced drone applications is assessed, comparing them with alternatives like Raspberry Pi, Arduino Uno, and BeagleBone Black. The analysis highlights the advantages and limitations of each platform in terms of power management, connectivity, and responsiveness. The conclusion underscores the necessity of proper power system design, including high-quality voltage regulators such as UBEC and PDB, to ensure flight stability and efficiency.
INFLUENCE OF SILICONE ADDITIVES ON STRUCTURE AND MECHANICAL PROPERTIES OF POLYURETHANE FOAM
The work presents a study of the effect of cilicone supplement on the structure and mechanical properties of polyurethane foam (PPU). PPUs were obtained by the pouring in plastic forms due to the synthesis of polyole (with the content of the foam) and the polyisocyanate components in the weight ratio of 2:4. The modifying silicone additive was introduced at the stage of mixing components in different weight ratios from 1 to 4 weight particles. The microstructure of the obtained foam with different weight content of silicone additives is analyzed, their porosity and structural and morphological features were evaluated and the behavior of modified PPU samples during deforming with static compression is considered. The pattern of change of porosity and mechanical characteristics is described due to the variation of the weight ratio of components. An increase in the particle of silicone additive leads to an increase in strength and mechanical characteristics at the same time as a decrease in PPU plasticity and an increase in the proportion of open pores in the material. The approaches described in the work can be used in the manufacture of foam structures that have predetermined characteristics.