Proceedings of Odessa Polytechnic University

Laboratory technology for extraction and analysis of vegetable oils

Ildar Rakipov — 2025-06-06

A technology for cold pressing, extraction, and analysis of oil from flax seeds, black cumin, grapes, rose hips, sea buckthorn, and pomegranate has been developed. The acid and iodine values were determined, and the molecular structure and fatty acid composition of the extracted oil samples were investigated using infrared spectroscopy and gas-liquid chromatography. Hexane and methylene chloride were identified as the most effective solvents for laboratory extraction in a Soxhlet apparatus. Preliminary maceration of the comminuted raw material was found to increase the lipid yield, an effect that was particularly pronounced in the extraction of oil from rosehip and sea buckthorn seeds. The determined acid and iodine values indicate a high content of unsaturated fatty acids and a low degree of hydrolysis in the investigated oil samples. The fatty acid profile of grape seed, rosehip, sea buckthorn, and black cumin oils is dominated by linoleic acid, with its content ranging from 41.2 ± 0.17% to 72.7 ± 0.06%. In flaxseed oil, linolenic acid is the predominant fatty acid (49.3 ± 0.04%), whereas in pomegranate seed oil, punicic acid prevails (86.1 ± 0.28%). Conversely, the concentration of linoleic acid in flaxseed oil is only 15.2 ± 0.04%. Significant amounts of linolenic acid were also detected in the oil samples from rosehip seeds (25.9 ± 0.11%) and sea buckthorn seeds (27.8 ± 0.16%). The oleic acid content varied from 4.3 ± 0.16% in pomegranate seed oil to 25.1 ± 0.12% in black cumin seed oil. Furthermore, palmitic (2.7 ± 0.07%...11.8 ± 0.00%), stearic (1.7 ± 0.03%...5.9 ± 0.01%), arachidic (0.1 ± 0.00%...1.0 ± 0.03%), and cis-11-eicosenoic (0.1 ± 0.00%...0.7 ± 0.04%) acids were identified in the studied samples. The infrared spectra of the oil samples exhibit absorption bands characteristic of C–H stretching and bending vibrations of methyl, methylene, and methine groups; C=C double bond stretching and bending vibrations; C=O carbonyl stretching vibrations; and C–O ester bond vibrations. The presence of characteristic peaks in the regions of 938 cm−1 and 989 cm−1 in the infrared spectrum of pomegranate seed oil confirms the presence of conjugated double bonds of punicic acid, which is the principal component of this oil.

Quantitative structure-property relationship analysis of critical properties of individual organic compounds

Egor Pesterev — 2025-06-12

This work presents the development and analysis of robust QSPR models for critical properties (pressure PC, temperature TC, and volume VC). The object of this study is a database consisting of 399 different organic compounds. These compounds include saturated and unsaturated hydrocarbons, aromatic hydrocarbons, heterocyclic compounds, alcohols, simple and complex ethers, and their derivatives. The database encompasses carbon-, halogen-, oxygen-, nitrogen-, and sulfur- containing compounds. The molecular structures of investigated compounds were previously modeled, standardized, and validated with respect to connectivity and uniqueness. Structural descriptors were calculated at the 2D molecular modeling level using the simplex approach. To differentiate simplex vertices, not only atom types but also other atomic characteristics were used, including van der Waals interactions (from the universal force field), and potentials of informational fields weighted by atomic properties such as partial charge, polarizability, electronegativity, and lipophilicity. In addition to simplexes, smaller fragments consisting of two and three atoms were also used for each compound of database. A total of 4,939 2D structural descriptors were calculated. The Random Forest (RF) method was applied to establish the relationships between the structural descriptors and the critical properties (PC, TC, VC). The developed 2D RF QSPR models showed high approximation accuracy (R² = 0.99) and predictive ability (R²oob = 0.90…0.97). Physicochemical interpretation revealed that electrostatic factors have the greatest impact on critical properties. For compounds lacking experimental data on the studied properties, predictions were presented using the developed RF models, and the applicability domain of the developed QSPR models was evaluated.

Method for creating a digital atlas of 3d models of human anatomy for prosthetics

Albert Volkov — 2025-06-11

Modern methods of 3D modeling and computer graphics play a key role in medicine, particularly in the development of personalized prostheses and implants. The use of 3D scanning technology enables specialists to accurately assess the extent of damage to the human body and to create detailed digital models of the affected areas. This opens new perspectives in diagnostics, surgical planning, and the production of customized prosthetic and implantable devices. The application of 3D reconstruction allows physicians to design medical devices that precisely replicate the anatomical structures of a specific patient. The implementation of such methods facilitates the selection of optimal treatment strategies, accelerates patient recovery, and improves the overall efficiency of the therapeutic process. Currently, there are numerous digital atlases of the human body; however, most of them are not specialized for prosthetic applications, which complicates the reconstruction of limbs considering individual anatomical features of patients. The aim of this work is to develop a method for creating a digital atlas of 3D human anatomy models to support clinical decision-making in prosthetics. The digital atlas provides an effective system for managing anatomical 3D models, with the capability of adapting data formats for 3D printing or reconstruction. It also enables the storage of precise anatomical characteristics in a structured form, specifically as descriptions of reference limb models linked to a specialized database, ensuring convenient data access and processing. As a result, the accuracy of 3D reconstruction is significantly improved, the process of prosthesis design is simplified, diagnostics and surgical planning are enhanced, and medical professionals gain effective access to anatomical 3D models and supporting information.

Segmentation-based approach for object detection

Natalia Volkova — 2025-06-12

This study proposes a segmentation-based approach for object detection, developed for analyzing aquatic behavior in controlled laboratory environments. The research focuses on overcoming detection challenges in long-term video recordings of bullheads housed in enclosed aquariums, where sediment drift, background instability, and partial occlusions often confound traditional tracking techniques. To address these issues, an approach based on the improved SLIC Superpixel segmentation method was proposed. The basic SLIC method was modified to incorporate multi-layer contrast features and neighborhood-based pixel uniformity checks. The proposed approach includes the following stages: preprocessing, segmentation, clustering, and post-processing. The preprocessing stage includes bilateral and median filtering, contrast and brightness normalization, and optional image upscaling to improve clarity. Subsequent background subtraction and context-aware thresholding within segmented regions help eliminate false positives caused by floating debris and occluded contours. At the clustering stage, a refined distance metric is introduced to evaluate pixel coherence in a multilayered feature space, which include LAB components, subtraction results, and histogram-equalized grayscale representations, improving segmentation accuracy. Additionally, at the post-processing stage fragmented object blobs are merged to enhance spatial continuity. Empirical validation was conducted on a dataset of bullhead video frames recorded under realistic aquatic conditions. The approach based on the improved SLIC Superpixel segmentation method demonstrated an increase in object detection accuracy of more than 6% compared to the approach based on the basic SLIC method. The modularity and simplicity of the proposed approach allow it to be easily extended to other biological objects − in particular, for the behavioral analysis of rodents − without relying on deep neural networks or computationally intensive frameworks, making it suitable for tasks in ethology, neuroscience, and precision aquaculture. Further research will be devoted to implementing the approach in real-time and advanced trajectory analysis.

Development of a criterion for selecting the level of wavelet decomposition for QRS detection in electrocardiogram signals using energy and entropy

Galina Shcherbakova — 2025-06-16

Analysis of electrocardiographic (ECG) signals is one of the key areas of modern biomedical engineering, providing the possibility of early detection of cardiac disorders such as arrhythmias, ischemia, and other cardiovascular pathologies. The most informative segment of the ECG signal is the QRS complex, which reflects the electrical activity of the heart ventricles and serves as an important marker for medical diagnostics. This work proposes a approach to selecting the optimal wavelet decomposition level based on quantitative analysis of energy and entropy characteristics of the signal at each level. The aim of the study is to construct a formalized criterion of informativeness for decomposition levels and evaluate the effectiveness of different types of mother wavelets for the task of extracting QRS complexes from ECG signals. Within the study, signals from the open MIT-BIH Arrhythmia Database were analyzed, and values of energy, entropy, and their ratio were calculated for each level of discrete wavelet transform. The results indicate that levels with high energy contribution and low entropy best reflect the localization of QRS complexes. It was shown that the choice of mother wavelet type significantly affects the distribution of these characteristics. The Daubechies wavelet was found to be the most effective for automated QRS detection, particularly at levels d3–d5. The scientific novelty of the work lies in the integration of the energy-entropy approach into the automated process of decomposition level selection without expert involvement. The practical significance is in the potential implementation of this method in computer diagnostic systems to improve their accuracy, reliability, and adaptability to various types of biomedical signals.

Formation of a signal with Hartley amplitude-phase modulation as the sum of two signals with Hartley amplitude modulation

Aleksandr Kokhanov — 2025-03-18

The paper presents the results of the research, which outcome in the development of a theoretical justification for a new type of modulation – Hartley amplitude-phase modulation. This type of modulation has an additional carrier that is orthogonal to the known amplitude-phase modulation. Moreover, the in-phase and quadrature components of the Hartley amplitude-phase modulation are Hartley amplitude modulations, and the Hartley amplitude modulation of the quadrature channel (the quadrature component) is an orthogonal Hartley amplitude modulation with respect to the in-phase channel. This also allows the formation of a Hartley amplitude-phase modulation signal with a square constellation - quadrature Hartley modulation. The paper also considers a method of demodulating a signal with Hartley amplitude-phase modulation using a synchronous detector. It is shown that a signal with Hartley amplitude-phase modulation has increased immunity to noise in the communication channel compared to the known amplitude-phase modulation. The paper also compares the properties of signals with quadrature Hartley modulation and a known signal with quadrature modulation. It is shown that the energy gain of a signal with quadrature Hartley modulation compared to quadrature modulation is 6 dB. In addition, quadrature Hartley modulation has the same average energy value per symbol as signals with QAM modulation. The paper presents the derivation of an analytical expression for calculating the signal-to-noise ratio for a signal from quadrature Hartley modulation. It is shown that the obtained theoretical results for calculating the error of a falsely received symbol agree well with the obtained results of simulation modeling. A comparison of the obtained simulation results when calculating the values for calculating the error of an erroneously received symbol for signals with Hartley quadrature modulation and known quadrature modulation is presented.

Peculiarities of BIM Technology Integration in Construction Industry Enterprises of Ukraine

Andriy Chumachenko — 2025-05-20

The article examines the relevance of integrating BIM technologies into the operations of Ukrainian construction enterprises as a strategic tool for digitalisation amid the country’s post-war recovery. It is substantiated that digital information modelling provides a comprehensive renewal of project management approaches, contributes to more effective decision-making, improves transparency in stakeholder interaction, and facilitates cost optimisation throughout the construction process. The evolution of the “Building Information Modelling” concept in international practice is analysed, and its role in transforming managerial and design-related activities in construction is outlined. Modern approaches to defining the essence of BIM are clarified, along with its core characteristics. Key problems and barriers hindering the large-scale implementation of BIM in the construction sector are identified, including insufficient investment resources, shortage of qualified professionals, low standardisation, and weak institutional support. An enterprise-level BIM implementation algorithm is proposed, accounting for technical, organisational, and economic factors. The approach also includes piloting on selected projects, developing digital platform infrastructure, and building a regulatory and legal framework. The article explores the potential of applying BIM in the reconstruction and modernisation of damaged infrastructure facilities funded by international aid, particularly under World Bank and EU support programmes. It is demonstrated that the adoption of BIM technologies will strengthen the competitiveness of Ukraine’s construction sector as it aligns with global digital governance standards. The study also highlights the promising research direction of integrating BIM with artificial intelligence tools, which can support process automation, reduce errors, and improve the quality of managerial decisions in construction.

Mathematical model of heat transfer in the “frozen casting mold – anti-adhesive coating – metal” system based on cellular automata

Mykola Zamiatin — 2025-05-21

A mathematical model for heat transfer in a “frozen casting mold – anti-adhesive coating – metal” system has been developed based on cellular automata. The modeling of thermal energy transfer is carried out using a special modification of the Stochastic Excitable Cellular Automata (SECA) method. Based on this mathematical model, heat transfer calculations were performed for the “frozen casting mold – anti-adhesive coating – metal” system. To determine the temperatures of the cellular automata at the initial step of the numerical experiment, each automaton is assigned initial values for temperature, thermal conductiv-ity, and heat capacity. Then, at each subsequent n-th time step, a new automaton temperature value is calculated, considering thermal fluxes from each neighboring automaton. When analyzing heat and mass transfer, it is crucial to account for heat consumption during the melting and evaporation of water, as well as heat release during moisture condensation. The heat of ice melting and water evaporation was consid-ered by increasing the specific heat capacity of the mold within the melting temperature range. The conducted research experimentally con-firmed the adequacy of the mathematical model for heat transfer in the “frozen casting mold – anti-adhesive coating – metal” system based on cellular automata. The investigations were performed using an AK5M2 alloy cast into frozen molds with an anti-adhesive coating. A nomogram is presented for determining the minimum thickness of the frozen core depending on the casting wall thickness and the mold cooling temperature. A method for selecting parameters using this nomogram is described. A mathematical dependency of the mold (core) heating depth to −5.0 °C on the casting wall thickness was derived. At this temperature, the strength of the frozen mold (core) is comparable to that of a sand-clay mold.

Hybrid intelligent adaptive fiber system for reducing nonlinear effects in WDM systems with metrological aspects

Oleksandr Kokhanov — 2025-03-18

Nonlinear optical effects, including self-phase modulation (SPM), cross-phase modulation (XPM), and four-wave mixing (FWM), significantly limit the performance of modern wavelength-division multiplexing (WDM) fiber-optic systems, leading to signal quality degradation, increased bit error rate (BER), and reduced maximum transmission distance. To overcome these limitations, this paper proposes an innovative hybrid intelligent adaptive fiber-optic system (IAF) that combines electro-optic and acousto-optic control of the refractive index in liquid crystal photonic crystal fibers (LC-PCF). The use of transparent indium-tin-oxide (ITO) electrodes and piezoelectric transducers enables precise and rapid dynamic modulation of the nonlinear coefficient n2 and effective mode area Aeff. This allows real-time adaptation of the optical properties of the medium, minimizing nonlinear distortions and enhancing transmission quality. A key element of the system is the integration of advanced artificial intelligence methods, specifically deep neural networks (DNN) and reinforcement learning (RL) algorithms, which optimize control parameters based on continuous signal monitoring. Such intelligent control accounts for variable operating conditions, accurately detecting and compensating nonlinear effects. Particular attention is given to metrological aspects: comprehensive sensor calibration methods and error assessment techniques have been developed to ensure measurement reliability and stability. This increases system robustness and its ability to maintain optimal parameters over extended periods. Numerical simulation results demonstrate significant system performance improvements: a reduction in the nonlinear coefficient γ by 25…50%, a decrease in BER by 20…35%, and an increase in maximum transmission distance by 15…25% in high-speed 400G and 800G WDM systems. The proposed hybrid intelligent adaptive system shows great potential for deployment in backbone, submarine, and long-haul fiber-optic networks, enhancing efficiency, reliability, and adaptability of modern telecommunication infrastructures.

Study of the modes of re-enable the asynchronous electric drive of a centrifugal pump

Andrii Boiko — 2025-04-21

A study of the dynamic modes of re-enable an induction motor of a centrifugal pump for a given power supply scheme has been carried out. The studies were conducted under the conditions of the specified technical requirements and the availability of technical data on the elements of the power supply system, electric drive and mechanism. The author's mathematical models of induction motors were used based on a generalized machine described in a three-phase fixed coordinate system taking into account the nonlinearities of the motor – iron losses, rotor current displacement effects and saturation along leakage paths and the main magnetic flux. An assessment is given of the qualitative and quantitative indicators of transient processes of the electric drive – currents, voltages, motor torques. The dynamics of voltages and currents in the phases of the engine are analyzed. The influence of non-zero initial electromagnetic conditions on the nature of transient processes is considered. It has been shown that overvoltage that occur when motors are switched on again in a circuit with permanently connected capacitors have an adverse effect on the operating electrical equipment. A solution to the problem is provided – the need to implement separate switching of the motor and capacitor sections, the use of thyristor devices to ensure favorable switching conditions, which allows reducing voltages and currents, minimizing peak torque values and ensuring stable operation of the system and also points out the advantages of using controlled starting devices.

Simulation of thermal modes of the absorption thermotransformer with heat pipes

Oleksandr Titlov — 2025-05-16

Methodology for thermal regimes simulation of absorption thermotransformer with heat pipes is proposed, which, through rational structural construction design, improves its thermal and power performance. Mathematical model has been developed for the thermal system comprising the “absorption thermotransformer evaporator – heat pipe – cooling object”, which enables numerical experiments to evaluate the influence of the following geometric and operating parameters, namely: depth, width, and height of the cooling facility enclosure; thickness of the cooling facility enclosure material; type of enclosure material; type of heat pipe used, taking into consideration its thermal resistance; and thickness of the thermal insulation barriers on the thermal and power characteristics of the absorption thermotransformer, specifically, the cooling facility enclosure. The basis of the thermal modes calculation methodology is the thermal balance equation, which accounts for the absorption thermotransformer evaporator cooling capacity, heat transfer from the surrounding environment through the cabinet walls, doors, and barriers, as well as heat input from the stored products. The varied parameters included: enclosure thickness – 0.003 m and 0.001 m; enclosure height – 0.160 m, 0.200 m, 0.280 m; enclosure depth – 0.225 m, 0.325 m, 0.425 m; and thermal resistance of the heat pipes – 0.01 K/W, 0.1 K/W, 1 K/W. The baseline designs for analysis were enclosures with L-shaped, U-shaped, and conventional heat pipes. As a result of the numerical experiment, it was proven that for a cooling object size of height – 0.160 m, width – 0.385 m, and depth – 0.225 m, the installation of a heat pipe equalizes temperatures to within 0.2 °C. The operating mode is reached approximately 20% faster. Increasing the depth of the enclosure from 0.225 m to 0.425 m reduces the efficiency of heat pipe usage by 45%, while increasing the height from 0.160 m to 0.280 m reduces efficiency by 2.6%. For developers of absorption thermotransformers with cooling object net capacity 12…30 dm³ and 100…180 dm³, the recommended enclosure design is with dimensions of 0.160×0.225×0.385 m, and with L-shaped or U-shaped heat pipes. The working fluid of the heat pipes is ammonia.

Autonomous hybrid system of combined energy supply with renewable energy sources

Hennadii Balasanian — 2025-06-12

The paper proposes a configuration of HSERES for the autonomous provision of electricity and heat supply to households, taking into account the energy potential of wind and solar energy in the Odesa region. The experimental climatic data on solar insolation and wind speed obtained from the meteorological station of the Odessа Polytechnic National University are generalised. The parameters of the wind speed distribution according to the Weibull function are obtained: the shape parameter, the scale parameter, and the mathematical expectation of the wind speed. The expressions for the integral repeatability function and the density function of the wind speed distribution are obtained. A methodology has been developed to determine the configuration and optimal parameters of a HSERES for individual households according to the criterion of minimising the cost component, which includes the costs of operation, repair, maintenance and capital expenditure in the generating capacity of the system. The optimisation problem was solved in Excel spreadsheets using the “Solution Search” option. The result of the solution is the optimal values of the total cross-sectional area of the wind turbine blades and the total area of photovoltaic panels that meet the conditions of the problem. The dependence of the configuration and parameters of the HSERES on the efficiency of the installed capacity and economic indicators of the system is investigated. During the autonomous operation of the HSERES, the excess energy potential of wind and sun is not used, as it requires seasonal accumulation of electricity, which is economically inexpedient and technically inefficient. The inclusion of an autonomous heat supply system in the configuration of the HSERES has led to a significant increase in the share of wind power generation capacity compared to the share of solar power plants. It is confirmed that the seasonal change in the energy potential of wind and solar resources can be mutually compensated by integrating two different in nature RES into a single system and optimising their generating capacities.

Thermal and hydraulic calculation of a Delta 125 steam generator for a power unit with an AP1000 reactor

Mark Galatsan — 2025-05-24

AP1000 power units have great advantages over VVER-1000 power units which are popular in Ukraine. They are equipped with passive safety systems that significantly reduce the risks of man-made accidents, even under conditions of extreme external influences. In addition, their design provides significant resource savings during construction and operation. The introduction of AP1000 reactors is not only a step towards restoring the country's energy potential, but also a strategic investment in the future. In this context, the thermal-hydraulic calculation of the Delta 125 steam generator, which is a key component of the AP1000 power unit, is extremely relevant and important to justify the feasibility of using such units in the Ukrainian power system. A comparative analysis of vertical and horizontal steam generators is carried out. The Delta 125 steam generator and its basic thermal scheme are described. The following thermal-hydraulic calculation was performed: the heat output of the economizer and evaporator sections, the coolant flow rate, the (t-Q)-diagram of the steam generator, the thickness of the walls of the heat transfer surface pipes and the length of the evaporator section pipes, and the heat transfer coefficient were calculated, the heat transfer surface area of the economizer and evaporator sections, the length and weight of the steam generator pipes, the hydraulic resistance of the first and second circuits, the sufficiency of the steam space for steam separation, the louver separator, the dimensions and weight of the main components of the body were determined. The cost of the steam generator, the estimated costs, and the dependence of the reduced costs on the coolant velocity were calculated.

Energy efficiency analysis of water heating system gas condensing boilers

Ganna Luzhanska — 2025-06-16

Increasingly relevant is the issue of using energy-saving technologies. This is due to the increase in the consumption of energy carriers, which reserves are limited. The heat supply system plays a significant role in heat consumption in the heat energy sector. The main consumer of thermal energy from the heat supply system is the water heating system. Any heating system consists of three main elements: a heat source, pipelines and heating devices. In a private residential building, a gas heating boiler is most often used as a heat source, where the coolant heating results from the fuel combustion. According to the standards adopted for determining the efficiency of boilers, admitted is that the boiler’s maximum possible heat output is equal to the lower heat of fuel combustion. The reason for this situation was the lack of technical possibility to use the latent heat of condensate without harm to the boiler design. In the 1980s, condensing boiler technology began to develop. Condensing boilers are able to achieve additional efficiency by using the energy of atmospheric moisture condensation in flue gases. Thus, the emergence of condensing technology influenced the change in the efficiency calculation rate and amounted to more than 100%. The design of condensing boilers with the use of an additional heat exchanger and condensate removal allows to obtain additional thermal energy released during the phase transition. Unlike conventional boilers, condensing units use most of the latent heat of vaporization. For efficient operation, not the lowest, but the highest heat of combustion is used, which is 10…11% higher for gas. The fuel efficiency in condensing boilers will be higher when operating in condensing mode. This mode is possible when the coolant is heated to a temperature never exceeding 57 °C. If the heated coolant temperature is higher, the water vapor will not condense from the combustion products and the condensing boiler efficiency will decrease. Thus, the condensing boiler maximum efficiency is achieved in the low-temperature heating mode. When this boiler operated in the 80…60 °C mode (normal water heating mode), the operation period is just slightly more than 30% of this one in the heating season: the efficiency is significantly reduced, to increase the efficiency of operation, indirect heating boilers or plastic heat exchangers and accumulator tanks are used. However, with this operating mode, the heating devices surface area increases by 2 times. The gas fuel economy during the operation of a condensing boiler compared to a traditional one per 1 kW of thermal energy is 0.023 m3/h, that is it allows 19% less gas consumption.

Determination of the probability of failures in the operation of elements of urban heat supply systems in extreme operating conditions

Anton Mazurenko — 2025-06-18

Modern centralized city or district heating systems of multi-apartment residential buildings, as well as administrative and industrial buildings, have a rather complex infrastructure. The main elements are heat generation systems, transport systems, and, accordingly, consumer subscriber inputs. The complexity of the system, which is determined by the necessary vital activity of many elements, affects the reliability of the heat supply infrastructure as a whole. The paper identifies the main reasons for the extreme operating conditions of heat supply systems in Eastern Europe and in present-day Ukraine. The main problems of operating systems during martial law are presented, including: damage to infrastructure due to hostilities, interruptions in the supply of fuel, water and electricity, difficulties in accessing repair work in the affected areas. The application of risk theory for complex systems in which the construction of a fault tree or event tree is widely used is justified. The advantage of the specified methods is the ability to determine the probability of failure or proper operation of the system as a whole with a known probability of failure of individual elements in extreme conditions. The paper considers the method of collecting and processing statistical data, as well as a rather promising universal method of expert assessments. For example, the probability of failure to connect a backup generator in the event of a shutdown or destruction of the main power supply system, the method of expert assessments was used for analysis. As a result of the study, the following were obtained: operating hours of power equipment in hours over years from commissioning; change in emergency shutdowns of the power unit over years. Analysis of the data provided indicates the presence of a period of increasing the reliability of power equipment as it is developed after commissioning, then, after some stabilization, an intensive decrease in reliability occurs, especially after the estimated resource is exhausted. The obtained pattern is characteristic of most technical systems.

Increasing the efficiency of ground-source heat pumps based on consumer operating mode data

Volodymyr Shevchuk — 2025-06-15

The introduction of renewable energy sources into the municipal heat power generation heat supply systems corresponds to modern policies of transition to "green energy" and decarbonization of both industry and various branches of power engineering. This study analyzes modern practices of heat pumps integration to autonomous heat supply systems with heat removal from the ground, identifying the main difficulties in geothermal heat pump systems implementation and operation. Based on the resulting analysis, a relevant direction of research on increasing the efficiency of autonomous heat supply systems based on geothermal heat pumps has been identified. To analyze the heat supply systems operation, a mathematical model has been selected that allows describing the processes of heat supply of various types of consumers with reference to the operation of a heat supply system based on geothermal heat pumps and heat accumulators. Experimental studies of the operation of a heat supply system based on a heat pump for the first heating season were conducted for a separate facility. Based on the data obtained, a generalization of the consumers’ operating modes depending on the 24-hourly period sector and ambient temperature has been carried out. The relevance of adjusting the operating modes of the heat pump installation was proven based on the experimental data obtained for the first period of system operation. The generalized data on the geothermal heat pumps operation allowed us to propose a solution to increase the heat supply system energy efficiency and the reliability of the heat generation system main elements. Mathematical modelling of the heat supply system operating modes in the facility based on geothermal heat pumps during the day was carried out, taking into account the available data on the main heat consumers’ operating mode. A pulsed mode of heat generation by heat pumps was proposed. Based on the obtained simulation results, a diagram of the heat supply system operation during the day was obtained. To equalize the operating modes of heat generators, the use of heat accumulators capable of reducing the heat pumps’ maximum calculated heat load during consumption peaks and ensuring the minimum needs of consumers during heat load declines was proposed.

Qualification of strategies for modernizing test frequency of safety systems at nuclear power facilities with extended time of fuel campaigns

Volodymyr Skalozubov — 2025-05-29

A risk-informed method for qualifying (substantiating) strategies for increasing the test periodicity of passive safety systems in the regimes of increasing the time of fuel campaigns of nuclear power facilities has been developed. The qualification criterion is the probability of failure of accident management systems for groups of initial accident events with a “tight” and “loose” reactor circuit. The qualification conditions are not to exceed the probability of failure of accident management systems of the modernized test strategy as to the design test strategy. Based on the developed method, it was recognized that a reasonable increase in the test periodicity of passive safety systems in the general case depends on the modernization of reliability indicators and the test periodicity of active safety systems at reactor power. Based on the qualification results, it was recognized that to increase the reliability of the emergency feed system of steam generators is the most reasonable strategy for increasing the test periodicity of passive safety systems. This can be provided with an emergency feed pump with a steam drive from the steam generators which get the required conditions for feeding steam generators at all accident stages at a pressure in the steam generators of at least 0.3 MPa. The developed method for qualifying strategies for test periodicity of passive safety systems in modes of increasing the time of fuel campaigns of nuclear power facilities can be implemented using sufficient operational data on the reliability of safety systems over the entire operation life.

Prediction of transboundary pollution of air and soil in Odesa region by fly ash from Moldavian SDPP

Oleksandr Butenko — 2025-04-18

Since at present, due to the lack of gas, a large energy enterprise Moldavian SDPP has returned to the use of solid fuel (coal), the problem of fly ash pollution of the territory of Odesa region has become relevant again. The article proposes a method for calculating the dispersion of solid particles with a shape close to spherical on the soil surface on the example of transboundary pollution of Odesa region by fly ash from power boilers of the Moldavian SDPP. In contrast to the current UND-86 standard, the method uses the general laws of aerodynamics and is based on determining the settling velocity of solid particles. It has been shown that, although fly ash from pulverised coal boilers consists of a large number of different substances, the bulk of it is silica, aluminium, iron and calcium oxides. They differ in fractional composition and material density. The proposed method takes this difference into account and allows predicting the coordinates of fly ash particles of a particular material and a certain size falling on the soil. The calculations showed that the chemical composition of soil pollution varies along the smoke plume line, with iron oxides predominating in the northern part of Odesa district and silicon dioxide in the immediate vicinity and in Odesa city. Due to the lack of reliable data on the fractional composition of fly ash from Moldavian SDPP, only an approximate estimate of dispersion was possible. However, even such estimates allowed us to conclude that ash particles spread much deeper into the territory of Odesa Oblast than according to the results of the UND-86. This is the basis for revising this methodology in terms of calculating the dispersion of fly ash from thermal power plants.

Features of parameter formation when comparing the efficiency of passenger elevators electric drives

Andrii Boiko — 2025-06-17

The current situation in the elevator industry in the housing and communal sector is a rather important and urgent problem. Most of the machines in the existing fleet have already worked out their resource by 60% or more. There was conducted an analysis of the current state of the passenger elevator fleet, both in residential buildings and in various types buildings of the communal and residential sector. It was found that conclusions regarding a significant increase in the energy efficiency of new types electric drives are often made on the basis of their comparison with technologically outdated winches with two-speed motors and worm gearboxes. It was determined that technical solutions are implemented at the expense of several compromises, namely: increasing the multiplicity of the pulley block; abandoning the counterweight; increasing the length of the ropes with a small cross-sectional area. It was proved that for an objective technical and economic comparison of elevator electric drives when a lack of data on their design characteristics, the correct application of both new and existing assessment methods is necessary. It is shown that before conducting a feasibility study, it is necessary to collect statistical data on the operation of both the elevator properly and its main systems. All parameters subject to analysis are divided into general, parameters of the lifting mechanism and electric drive. From practical experience, it is shown that the technical and economic features of the elevator electric drive largely depend on the presence or absence of a reducer, the winch type and the control system used, as well as on these elements’ operating modes. Based on the selected mathematical models of the elevator operation in specific conditions, optimal diagrams of the movement of at different distances of its movement were obtained, as well as calculated kinematic diagrams of the elevator car lifting mechanisms of elevators with direct suspension and with polyspast suspension. The parameters of the elements of a typical elevator lifting installation and static forces on the rim of the rope-driving pulley and load moments during lifting depending on the stop number were also determined. The obtained research results allow further identifying the main variants of popular elevator systems that are subject to technical and economic comparison and differ in design.

Modeling of quality characteristics at the finishing operations of workpieces using vibration resistance indicators

Anatolii Usov — 2025-06-12

The paper addresses the determination of the qualitative characteristics of machined workpieces surfaces in finish operations based on the vibration resistance indicators of the “machine – fixture – tool –workpiece” system. After finishing, the surface of the workpieces is never perfectly smooth, but always exhibits microscopic irregularities that form roughness and microdefects. In the operations preceding grinding, surface roughness influences stress concentrations, vibration activity, and the formation of thermal defects that, under the thermomechanical phenomena that accompany finish machining, cause burns, cracks, and chipping of the workpiece. The cutting process generates intense vibrations in the tool, the workpiece, the machine itself, and the chip removed. The stated problem and its proposed solution focus on studying the oscillations of the workpiece surface under the action of cutting forces. Calculation results make it possible to evaluate the vibration resistance of the entire “machine – fixture – tool –workpiece” system by matching oscillation amplitudes and periods. The proposed method for identifying the resonance zones of the system’s force oscillations enables control of the grinding process when using a specific tool. This control is achieved by selecting cutting speeds, determining optimal cut depths, or adjusting the workpiece mass. The method is recommended for implementation in the practice of optimizing grinding processes for materials prone to thermal defects. Experimental validation of the model was carried out on workpiecess made of 102Cr6 and X12CrNiTi18-9 steels and titanium alloys, confirming prediction accuracy within 10% deviation. The results obtained have allowed the development of recommendations for choosing grinding regimes and parameters, as well as fixture and tool design, to ensure process stability and reduce the occurrence of thermal and vibration-induced defects.

Experimental determination of the influence of spindle imbalance with boring bar on machining accuracy

Andrii Orhiian — 2025-03-17

The influence of the parameters of the elastic system of the finishing and boring machine on static deformations, oscillations and accuracy of fine boring is studied. Based on experimental studies of the effect of spindle imbalance with a boring rod on machining accuracy, a method was developed for calculating deviations from roundness caused by the action of cutting forces and centrifugal forces on elastic systems with anisotropic rigidity. Static errors and deformation features in the closed dynamic system of the machine were also studied. The total deviation from roundness caused by elastic deformations is calculated as the sum of static and dynamic components. The mean values of the imbalance me, the mean square deviations of χ and the deviation of the maximum values of the imbalance memax to the permissible [me] are given. The effect of imbalance on the roughness of the treated surface has been established. Since the increase in deviations from roundness is caused by the ovalization of the hole, the reason for the violation of the accuracy of the cross-sectional shape with an increase in the transverse force is the anisotropy of the radial rigidity of the elastic system of the machine. Testing units of the same standard size under the same conditions, the ovalization of the holes does not remain constant, therefore, the anisotropy of elastic properties is associated with the individual quality of the spindle assembly, namely, with the accuracy of individual parts of the unit and their assembly.

Structural analysis of a third-class ten-link mechanism with two complex links

Sergey Koshel — 2025-03-22

The basis of a technological machine is a mechanism whose main task is to convert the predetermined mechanical motion of the moving link of the initial mechanism into the motion of the driven link required to perform a technological operation, with the working body of the machine positioned at a specific point of this link. If the machine structure includes a complex mechanism with two or more initial mechanisms, the motion of each driving link influences the motion law of the point where the working body is located. This can lead, for example, to its stoppage and remaining in a stationary state for a certain period determined by the execution of the technological operation. Particular attention should be paid to technological operations that involve the “transfer” of working material from one working body to another, which operate synchronously. Reliable execution of such an operation is possible either by stopping one of the working bodies or by minimizing their relative velocities. The presence of two, three, or more driving links in the mechanism structure, on the one hand, ensures a positive outcome for the high-quality execution of the technological operation, but on the other hand, significantly complicates the analysis and synthesis of such mechanical systems. When studying multi-link systems with multiple driving links, it becomes necessary to develop and implement a research plan for each specific case of such complex mechanisms, taking into account their structural features. For a third-class mechanism with two complex links and three driving initial mechanisms, a structural analysis plan has been developed and implemented to determine the sequence of further studies, such as kinematic analysis. The ten-link third-class mechanism was structurally analyzed using a step-by-step examination of conditional mechanisms with a single driving link in their structure. The results of this sequential analysis allowed for the additional determination of the instantaneous kinematic parameters of the absolute motion of a link, whose motion is conditioned by its kinematic connection to the fixed link of the mechanism. Ultimately, this made it possible to analyze the third-class mechanism with three driving links in a manner typical for the study of second-class mechanisms. The proposed method for analyzing third-class mechanisms may be useful for conducting similar studies on higher-class mechanical systems.

Control of the milling mode of a thin-walled console plate by indirect indicators

Andrew Tkach — 2025-05-01

The article presents a theoretical study of the change in the deflection of a thin rectangular plate depending on the position of the point
of application of force simulating the load from the cutter. The modeling was carried out for two typical processing trajectories  along the length
and along the width of the plate. The deflections and the corresponding stiffness values are calculated, the dependencies are obtained and their
features are interpreted. It is found that the adopted algorithm of the calculation is similar to the calculation algorithms used in existing CAE systems.
Based on this, it is proposed to use the data, in particular the plate deflection value, as an indirect indicator for controlling the milling mode. The
indirect indicators adopted as the initial ones are approximated as a power polynomial with a certain approximation reliability R2. It is proposed to
use the obtained polynomials to create the corresponding inversely proportional polynomials that determine one of the main indicators of the milling
mode  the linear feed of the spindle. The software implementation of the proposed solution was carried out using an extended G-code, which
suggests the use of the proposed solution for a wide range of CNC milling machines. Practical testing of the obtained software solutions was carried
out, confirming their full operability. The research results allow increasing the stability of the milling process when processing low-rigid cantileverfixed
parts on machines without an active control system, including active feedback “part  tool  machine”. This approach allows using cheaper
machines while obtaining acceptable quality of machined surfaces, which, in turn, determines a decrease in the cost of manufactured products and
increases production efficiency.

Increasing the machining productivity of the firing pin body part through automated tool selection

Oleksandr Yevdokymov — 2025-06-15

The research addresses the issue of increasing the machining productivity of the “Firing Pin Body” part of the aerosol smoke system AEK-902 “Khmara”. The Ukrainian Armed Forces actively use the “Khmara” system to create dense smoke screens, including during the evacuation of personnel from the battlefield. Ensuring the operational readiness of the “Khmara” system is a relevant issue. The “firing pin body” part is important to the smoke grenade launch system. Automated tool selection is proposed to enhance the machining productivity through optimal tool and cutting parameters. A comparison of solutions from three leading cutting tool manufacturers − Walter, Sandvik Coromant, and Iscar − was conducted. The selection was made using software from the manufacturers: Walter “GPS”, Sandvik Coromant “ToolGuide”, and Iscar “ToolAdvisor”. The comparison was based on machining productivity and tool life. For machining the part, the following technical solutions were proposed: for operation 010, use the following tools: through cutter DSSNL2020K12 with SNMG120416-PR4335 insert, through cutter CP-25BL-2020-12 with CP-B1216D-M7 4425 insert, through cutter DCLNL 2525M 19 with CNMG 190612-PR 4425 insert, drill 462.1-1020-051A1-XM-X2BM, boring tool A08H-SCLCL06 with CCMT 060208-UM 1125 insert, drive tool drill 862.1-2500-225A1-GM X2BM, drive tool tap T300-PM100JA-M3 P1PM, cutoff tool QD-NN2F33-25A with QD-NF-0250-0003-CH 1225 insert. For operation 020, use: through cutter DSSNL 2020K 12 with SNMG 120416-PR 4425 insert, boring tool A08H-SCLCL06 with CCMT 060208-UM 1125 insert, boring tool A16PR-SSKCL09 with SCMT 09T312-PR 4425 insert, and drive tool drill 462.1-0650-020A1-XM-X2BM. The proposed set of cutting tools enables full and efficient machining of the firing pin body part.