2023

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Adaptation of LambdaMART model to semi-supervised learning
(Національний технічний університет "Харківський політехнічний інститут", 2023) Yamkovyi, Klym Serhiyovych
The problem of information searching is very common in the age of the internet and Big Data. Usually, there are huge collections of documents and only multiple percent of them are relevant. In this setup brute-force methods are useless. Search engines help to solve this problem optimally. Most engines are based on learning to rank methods, i.e. first of all algorithm produce scores for documents based on they feature and after that sorts them according to the score in an appropriate order. There are a lot of algorithms in this area, but one of the most fastest and a robust algorithm for ranking is LambdaMART. This algorithm is based on boosting and developed only for supervised learning, where each document in the collection has a rank estimated by an expert. But usually, in this area, collections contain tons of documents and their annotation requires a lot of resources like time, money, experts, etc. In this case, semi-supervised learning is a powerful approach. Semi-supervised learning is an approach to machine learning that combines a small amount of labeled data with a large amount of unlabeled data during training. Unlabeled data, when used in combination with a small quantity of labeled data, can produce significant improvement in learning accuracy. This paper is dedicated to the adaptation of LambdaMART to semi-supervised learning. The author proposes to add different weights for labeled and unlabeled data during the training procedure to achieve higher robustness and accuracy. The proposed algorithm was implemented using Python programming language and LightGBM framework that already has supervised the implementation of LambdaMART. For testing purposes, multiple datasets were used. One synthetic 2D dataset for a visual explanation of results and two real-world datasets MSLR-WEB10K by Microsoft and Yahoo LTRC.
Agaricus bisporus and Flammulina velutipes mushrooms on quality of chicken batters
(Національний технічний університет "Харківський політехнічний інститут", 2023) Fotina, Tetiana; Xiong, Anqi; Koshel, Olena; Sabadash, Sergiy; Yankovskiy, Roman
It was noted the modern tendencies of the cultivated mushrooms using as a fat substitutes in the technology of low-fat meat products. It was states that variety of low-calorie, low-fat foods have come to the fore, and quickly become the mainstream of the future development of food. The mushrooms are worldwide cultivated and rich in protein, vitamins, dietary fiber, amino acids, polysaccharides, minerals, but low in fat and calories In order to develop low-fat meat products, the compound of Agaricus bisporus and Flammulina velutipes mushrooms were used as fat substitute to replace the pork-back fat in chicken batters. The amino acids content of these mushrooms allows receiving a nice flavor and can be use in the minced meat. It was use a chicken meat as a wellliked raw material for emulsified products. For preparation of meat batters was used chicken breast, salt and sodium tripolyphosphate. The chicken meatballs were prepared with the cultivated mushrooms as fat-substitutes.The mushrooms were compounded to replace fat in chicken batters, and the effect of compounding these mushrooms on the quality of chicken mince was investigated to find the optimal ratio of fat replacement. The cooking loss, water holding capacity, color, texture and rheological properties of chicken batters were studied. The results showed that the compound of Agaricus bisporus and Flammulina velutipes improved the texture, increased the water holding capacity, redness and yellowness, and reduced the cooking loss and brightness of chicken batters. When the ratio of Agaricus bisporus and Flammulina velutipes was 2:1 to replace 30% pork-back fat, chicken batters showed the best quality. In conclusion, the combination of Agaricus bisporus and Flammulina velutipes is a promising fat substitute in the development of low-fat meat products.
Algorithm and software of medical personnel selection system
(Національний технічний університет "Харківський політехнічний інститут", 2023) Yamburenko, Viktor Viktorovych; Liutenko, Iryna Viktorivna; Kopp, Andrii Mykhailovych; Holovnia, Dmytro Mykolaiovych
There is a lot of routine work in any organization, including in recruitment agencies. Effective management organization and automation of activities of employees of recruiting agencies is not an easy task. The system should automate the routine actions of workers of recruiting agencies and be convenient for their clients. This paper proposes an approach to automating the selection of necessary medical staff. Not all information systems used by recruiting agencies can compare candidates and generate results that include several of the best candidates. Based on the analysis of the subject area, groups of parameters that significantly affect the choice of medical personnel were determined. The proposed approach is to analyze the request from the client, and then in the system find requests of other clients similar to it in terms of parameters, for which a candidate has already been found. The next step is to take the profiles of healthcare professionals that have been suggested for these requests (they act as benchmarks) to further compare them with existing candidates. Each employee profile parameter has its own similarity function. Available candidates will receive scores and will be ranked. We also additionally adjust the assessment by comparing candidates with the current request. Software was developed to automate the selection of medical personnel. For its implementation, a three-level client-server architecture is proposed. MVC (Model View Controller) architecture was chosen for the server part. The Single Page Application architectural template is used for the client part. The server part is divided into three layers, which further demarcate and structure the responsibilities of the system components. .NET technologies are used to implement business logic. SQL Server is used for the server and database provider. The use of the software implementation of the developed system demonstrated quite good results. The average time for selecting the 10 best candidates out of 500 is 0.4 seconds, and the processing of only 1 resume by a person takes several minutes.
An algorithm for NLP-based similarity measurement of activity labels in a database of business process models
(Національний технічний університет "Харківський політехнічний інститут", 2023) Kopp, Andrii Mykhailovych; Orlovskyi, Dmytro Leonidovych
Business process modeling is an important part of organizational management since it enables companies to obtain insights into their operational workflows and find opportunities for development. However, evaluating and quantifying the similarity of multiple business process models can be difficult because these models frequently differ greatly in terms of structure and nomenclature. This study offers an approach that uses natural language processing techniques to evaluate the similarity of business process models in order to address this issue. The algorithm uses the activity labels given in the business process models as input to produce textual descriptions of the associated business processes. The algorithm includes various preprocessing stages to guarantee that the textual descriptions are correct and consistent. First, single words are retrieved and transformed to lower case from the resulting textual descriptions. After that, all non-alphabetic and stop words are removed from the retrieved words. The remaining words are then stemmed, which includes reducing them to their base form. The algorithm evaluates the similarity of distinct business process models using similarity measures, including Jaccard, Sorensen – Dice, overlap, and simple matching coefficients, after the textual descriptions have been prepared and preprocessed. These metrics provide a more detailed understanding of the similarities and differences across various business process models, which can then be used to influence decision-making and business process improvement initiatives. The software implementation of the proposed algorithm demonstrates its usage for similarity measurement in a database of business process models. Experiments show that the developed algorithm is 31% faster than a search based on the SQL LIKE clause and allows finding 18% more similar models in the business process model database.
Analysis of the application of modern means of detection and measurement of carbon monoxide when using alternative sources of electricity supply during the war in Ukraine
(Національний технічний університет "Харківський політехнічний інститут", 2023) Khondak, Inna; Berezutska, Nataliia; Stytsenko, Tetiana
The article examines the impact of carbon monoxide on the human body, as well as the necessity of its detection and measurement. Carbon monoxide poisoning is very dangerous for human health and is accompanied by negative consequences and requires the implementation of new means of its timely detection and measurement. The article identifies the main sources of carbon monoxide, as well as assesses its impact on public health. The choice of modern means of detecting and measuring carbon monoxide is an important and necessary component of protecting people in modern realities. The work examines and analyzes the technical capabilities of modern capabilities of determining the level of carbon monoxide, defines the main models of carbon monoxide detectors, and also classifies and systematizes the peculiarities of their operation. The most convenient and practical portable carbon monoxide sensor. It does not require stationary installation. This is especially important in closed rooms, where carbon monoxide poisoning can occur instantly. The article analyzes literary sources in the field of the main types of alternative energy sources used in Ukraine during emergency and planned blackouts, as well as the dangers associated with them. The influence of dangerous and harmful factors affecting the human body during the use of these devices is considered: power banks, generators, batteries and inverters. The analysis of scientific research on ensuring safety when using alternative energy sources in domestic premises, private and multi-story buildings, factories, underground passages and storages was performed. The features of each type of modern signaling devices are analyzed. Recommendations are provided for the selection of modern means of detecting and measuring carbon monoxide.
Application of bayesian regularization for improving the quality of electrical energy in the electrical supply system
(Національний технічний університет "Харківський політехнічний інститут", 2023) Yagup, Kateryna Valeriivna; Yagup, Valery Gryogorovych
The possibility of using neural networks in the field of the energy coefficients correction of a power supply system with uneven load in phases is being studied. This need is justified by the fact, that the calculation of the necessary parameters of the symmetry-compensating device was previously based on the Nelder – Mead search optimization method. Search optimization performing is computationally expensive, takes long computation times, and may calculate anomalous values. The article develops the idea of using technology for predicting the parameters of a symmetry-compensating device, based on neural network modeling using Bayesian regularization. For a given set of initial data, the best selected configuration turned out to be a neural network of two layers, implemented in the MATLAB package using the machine learning tool Neural Network Toolbox. The network input parameters are a set of tuples, consisting of load values in each of the three phases of the power supply system, which are resistive-inductive in nature. There are six input quantities in total (load resistance and inductance values in each of the three phases) and all their values are different, which causes current asymmetry in the network and reactive power. The target matrix is formed from tuples, consisting of three values, which are the parameters of the symmetrical compensating device, calculated by the optimization method, in such a way as to compensate reactive power and to balance currents in the network. The number of data tuples, required to train a neural network was determined empirically. During the experiments, the optimal number of neurons in the neural network was also revealed. The use of the generated neural network to calculate the parameters of the symmetry-compensating device determined approximate solutions is comparable in accuracy to the values, found by optimization methods. With the help of the generated neural system, adequate quasi-solutions for calculating the parameters of the symmetry-compensating device were determined, which, in case of calculation, using the optimization method, led to anomalous values, that didn’t optimize the energy coefficients of the power supply system to the required extent. Also, such neuropredictions protect the system from receiving excessive high parameters of symmetry compensating device, which can be obtained with an optimization approach.
Blockchain platform selection and software development for decentralized exchange of business process models
(Національний технічний університет "Харківський політехнічний інститут", 2023) Kopp, Andrii Mykhailovych; Orlovskyi, Dmytro Leonidovych; Olkhovyi, Oleksii Mykhailovych
Modern organizations employing the Business Process Management (BPM) approach typically handle collections of hundreds or even thousands of business process models. Business process modeling stands as the central technology within the entire BPM methodology. In line with the BPM lifecycle, these models visually represent current organizational activities that necessitate improvement using various diagramming notations. These graphical business process models can subsequently be employed to analyze ongoing activities in the enterprise, identifying potential drawbacks or "weak spots" that hinder the company’s performance. Through business process models, organizations can modify the "virtual twins" of their organizational workflows, conduct simulations, and make informed decisions for business process improvement. Thus, business process models constitute the most valuable assets of the organization, conveying knowledge about ongoing activities and potentially encapsulating the best organizational or industry practices. The implementation of a centralized database for business process models can significantly benefit the entire organization, enhancing the efficiency of knowledge sharing and accumulation. However, centralized business process model repositories prove less efficient for inter-organizational knowledge exchange. Additionally, most business process models require significant person-hours for development and cannot be shared freely with competitors. The exchange of business process models should adhere to established mechanisms for managing valuable digital assets. Presently, Distributed Ledger Technologies (DLT), especially Blockchain, have gained enormous popularity. Therefore, we can employ the principles of Blockchain technology and the cryptocurrency industry to create software for the Decentralized Exchange (DEX) of business process models. This study explores the selection of a DLT platform and the development of software for the decentralized exchange of business process models, utilizing asset tokenization and smart contract technologies.
CFD моделювання теплоаеродинамічних характеристик композиційної плоско-овальної труби з неповним гофрованим оребренням
(Стильна типографія, 2023) Баранюк, Олександр Володимирович; Воробйов, Микита Валерійович; Алексеїк, Євгеній Сергійович; Мазуренко, Антон Станіславович
Стаття присвячена дослідженню теплоаеродинамічних характеристик оригінальної конструкції теплообмінної поверхні – плоско-овальної труби з неповним гофрованим оребренням, яка може бути використана для модернізації сучасного теплообмінного обладнання. Мета роботи полягала у попередній оцінці ефективності плоско-овальних труб з неповним гофрованим оребренням та отриманні емпіричної залежності для розрахунку за допомогою CFD-моделювання. Об’єкт дослідження – вимушена конвекція при поперечному омиванні композиційної плоско- овальної труби з неповним гофрованим оребренням. Предмет дослідження – теплообмін та аеродинаміка при поперечному омиванні композиційної плоско-овальної труби з неповним гофрованим оребренням. В роботі отримані значення безрозмірного коефіцієнту тепловіддачі та втрати тиску, а також представлена розрахункова залежність для визначення коефіцієнту тепловіддачі та аеродинамічного опору згаданих типів труб. Верифікація даних проводилась з гладкою трубою та трубою зі спіральним оребренням. Науковою новизною роботи є встановлення того факту, що плоско-овальні труби з неповним гофрованим оребренням мають вищий коефіцієнт тепловіддачі порівняно з гладкими трубами (в середньому на 45 – 50 %) та спірально-стрічковою оребреною трубою (в середньому на 25 – 30 %) в умовах одночасного зростання аеродинамічного опору на 25 – 30 при однакових витратах теплоносія. При практичному використанні отриманих результатів конструктори зможуть збільшити площу поверхні теплообміну, що робить ці труби перспективними для використання в енергетиці та промисловості, зокрема сухих градирнях АЕС та ТЕС, теплових утилізаторах котлів, ГТУ тощо.
ChatGPT як інноваційний помічник в управлінні фінансовою стійкістю
(Національний технічний університет "Харківський політехнічний інститут", 2023) Гаврик, Аліна Андріївна; Назарова, Тетяна Юріївна
Досліджено роботу штучної інтелектуальної системи, яка базується на моделі глибокого навчання Generative Pre–trained Transformer. Зазначено, що вивчення штучного інтелекту в сучасному світі є одним з найважливіших та найшвидше розвиваючихся напрямків технологій. Розглянуто останні наукові праці та виділено ключові результати науковців. Проаналізовано основні принципи роботи системи та її можливості використання в оцінці фінансової стійкості підприємств. Зауважено зростання світового обсягу інвестицій в сферу розвитку штучного інтелекту та машинного навчання в останнє десятиліття та прогнозне значення збільшення інвестиції в найближчі роки.. Розглянуто основні способи впливу ChatGPT на фінанси та його здатність обробляти складні фінансові запити. Представлено практичне використання моделі та обгрунтовано можливості її функціонування в пошуку рішень і допомоги в аналізі фінансової стійкості. Надано основну інформацію щодо методів покращення фінансової стійкості підприємства через аналіз фінансових даних та прогнозування різних сценаріїв. Використано ChatGPT для аналізу фінансової стійкості підприємства на прикладі неіснуючої компанії, згенерованої штучним інтелектом. Розкрито аналіз показників фінансової стійкості з розрахунками, що підтвердили фінансову стійкість підприємтсва з можливими ризиками до врахування. Виявлено переваги та недоліки моделі та зроблено висновки щодо доцільності використання її в реальних умовах. Визначено, що використання ChatGPT для аналізу фінансової стійкості підприємства потребує обережності та врахування досліджених проблем. Надано рекомендації, щодо покращення роботи алгоритму машинного навчання для виявлення специфічних фінансових термінів та їх зв'язків, а також для зниження шуму в текстах та вдосконалення функцій з графічним представленням даних.
Classification of nuclear NPP reactors
(Національний технічний університет "Харківський політехнічний інститут", 2023) Yefimov, Olexander Vyacheslavovych; Tiutiunyk, Larysa Ivanivna; Kavertsev, Valery Leonidovich; Harkusha, Tetyana Anatoliivna; Sydorkin, Igor Dmytrovych
The article deals with the classification of NPP nuclear reactors. A nuclear reactor is a device in which a chain reaction of nuclear fission of heavy elements uranium, plutonium, and thorium takes place, which controls and maintains itself. The possibility of such a reaction is ensured by the fact that each act of nuclear fission produces two or three neutrons capable of causing the fission of other nuclear fuel nuclei loaded into the reactor. In the reactor, simultaneously with the nuclear fission process, there is always, firstly, the absorption of neutrons by materials located in the active zone, and, secondly, the outflow of neutrons from the active zone of the reactor. These two factors make it possible to regulate the nuclear fission process so that the number of neutrons in the active zone and the number of acts of fission per unit of time are constant. Nuclear reactors are very diverse in terms of their parameters, purpose, design and a number of other features. Nuclear reactors can be classified according to the following main distinguishing features: the amount of neutron energy that causes nuclear fission; by type of retarder; according to the type and parameters of the coolant; by constructive execution; according to the compositional decision; by appointment. At nuclear power plants, nuclear reactors are used to generate electrical and thermal energy. At nuclear power plants, they are used to generate thermal energy for the purpose of heating and industrial heat supply. In ship power plants, they are used as sources of thermal, mechanical and electrical energy.
Comparative analysis of software systems for hydraulic turbine flow simulation
(Національний технічний університет "Харківський політехнічний інститут", 2023) Krupa, Y. S.; Demchuk, R. M.; Volobuiev, A. V.; Kis, S. L.
A comprehensive review of modern software complexes used for calculating spatial flow in hydraulic turbine flow parts was conducted. The widely used software system, Ansys, was analyzed. An overview of Ansys was provided, including its history, popularity within the CFD community, key features, and capabilities for analyzing the flow parts of hydraulic turbines. The preprocessing tools, solver parameters, post-processing functions, and visualization capabilities of Ansys were described. The advantages and limitations of using Ansys for calculating spatial flow in hydraulic turbine flow parts were analyzed. The open-source CFD software complex, OpenFOAM, was discussed. The main functions and capabilities of the OpenFOAM program were described. Information about solver libraries, meshing capabilities, advantages, and limitations for analyzing hydraulic turbines was presented, along with insights into the support from the scientific community and resources available to OpenFOAM users. SolidWorks FlowSimulation, which integrates with SolidWorks software, was examined. The unique features of SolidWorks FlowSimulation for analyzing spatial flow in hydraulic turbines were highlighted. The possibilities of CAD integration and the advantages of accurate geometric models were discussed. The capabilities of parametric analysis were explored, and the advantages and limitations of using SolidWorks FlowSimulation for calculating spatial flow in hydraulic turbine flow parts were analyzed. A comparison of the three software complexes was conducted based on their capabilities, ease of use, accuracy, computational resources required, and cost. An assessment of the advantages and disadvantages of each program was provided, along with recommendations for choosing the most suitable program based on specific use cases, objectives, and user requirements. This article serves as a valuable resource for engineers, designers, and researchers seeking insights into the available software systems for analyzing hydraulic turbine flow parts. It enables them to make informed decisions in selecting the most suitable software system based on their specific requirements, ultimately contributing to the optimization of hydraulic turbine performance and efficiency.
Conflict managment in the international organization
(Національний технічний університет "Харківський політехнічний інститут", 2023) Novik, I. O.
The article is devoted to the fact that conflicts are inevitable in our lives and that conflict management in the international organization is one of the most important areas in the activities of the head because it affects the productivity of employees and it affects the results of the work of the organization as a whole. The article discusses the mechanisms of management as well as the definition of conflict and how to manage stress to avoid conflict situations in the organization. For most companies, the main reason was and remains a conflict of interest of employees, and that would prevent or resolve an existing conflict the article reveals the stages of conflict development and the characteristics of ways to resolve conflicts, as well as methods of behavior of individuals or groups in the conflict, called methods of conflict prevention in the organization, reveals what is conflict forecasting since it plays a not unimportant role in personnel management in the organization. To resolve conflict situations, the leader can turn to methods such as smoothing, cooperation, compromise, etc. The use of these strategies can help resolve conflicts. One of the most effective methods of conflict resolution is a compromise, since most often the conflicting parties use a compromise, since the friendly steps towards which one of the conflicting parties makes, make it possible to achieve an asymmetric (one side can give in more, the other will give in less) or even symmetrical ( parties are trying to make mutual concessions approximately equal to each other) agreement. The main thing to remember is that managing conflicts between employees is a controlled process, and even people with opposite views on the situation can agree. And do not forget about the prevention and forecasting of conflicts in order to prevent the appearance of discontent and tension in the team. Conclusions based on the results of the study are formulated.
Construction materials of active zones of new generation nuclear reactors
(Національний технічний університет "Харківський політехнічний інститут", 2023) Yefimov, Olexander; Pylypenko, Mykola; Tiutiunyk, Larysa; Harkusha, Tetyana; Yesipenko, Tetyana; Motovilnik, Anastasiia
The materials of the article consider the analysis of construction materials of active zones of new generation nuclear reactors. The analysis reflects general ideas about the development of reactor technologies: in the 1950s and 1960s, the first generation of reactors was created; in the early 1970s, the operation of industrial reactors began - reactors of the second generation: pressurized water reactors (WWER, PWR), boiling water reactors (RBMK, BWR), heavy water reactors (CANDU), as well as gas-cooled reactors (AGR). Further development of some types of reactors made it possible to create reactors of the third generation in the 1980s. Priority when choosing directions of development in the category of revolutionary projects should have proposals capable of bringing a new quality to solving the problems of the nuclear energy industry of the future. Promising reactors have advantages in economy, safety, reliability and non-proliferation of nuclear materials. The effectiveness and reliability of structural materials are determined by the totality of changes in the characteristics of the materials as a result of the entire complex of phenomena occurring in them in the field of irradiation, in connection with the changing parameters and operating conditions. The use of high-purity metals as initial components of new structural materials and the development or optimization of their smelting technologies should ensure the required level of characteristics and properties of products made from them. The implementation of these concepts should be ensured by the development of new structural materials: ferritic-martensitic and austenitic steels, nickel and other new alloys.
Construction of statistical models of chemical and technological objects on the basis of a complete factor experiment
(Національний технічний університет "Харківський політехнічний інститут", 2023) Prishchenko, Olga Petrivna; Chernogor, Tetyana Timofiyivna
The article deals with the construction of a mathematical model of the process, which is created based on the results of a full factorial experiment. Often, only the results of experimental studies carried out at such objects are the information, based on the processing of which, according to the obtained mathematical model of the object, a high-quality control algorithm for this object can be implemented. At the same time, the construction of a mathematical model that describes the technological process with the required accuracy often involves a huge amount of work at the stage of experiments. The task of planning experiments is to establish the minimum required number of them and the conditions for their implementation, to choose methods for mathematical processing of the results, and to make decisions. Designing experiments significantly reduces the number of experiments required to obtain a process model. An active experiment involves a purposeful choice of factor values. Compared to a passive experiment, such an experiment turns out to be more efficient and economical, since the amount of experimental work is significantly reduced. In this article, in relation to chemical technology, the issues of organizing an experiment, mathematical processing of experimental data and mathematical planning of an experiment in the search for optimal conditions for conducting a technological process are described. Mathematical modeling and optimization of chemical technology objects is of great importance for obtaining higher professional education for students of the Educational and Scientific Institute of Chemical Technology and Engineering.
Correlation functions and quasi-deterministic signals
(Національний технічний університет "Харківський політехнічний інститут", 2023) Cheremska, Nadezhda Valentinovna
When processing data on random functions, they are most often limited to constructing an empirical correlation function. In this regard, the problem arises of constructing a random function (a quasi-deterministic signal) determined by a finite set of random variables and having a given correlation function. Moreover, a random function can often be considered Gaussian, since in many cases a random signal is obtained at the output of the system, which is fairly well approximated by a Gaussian. For stationary random processes and for random fields, this problem has been considered. For random sequences and discrete random fields, as well as for non-stationary random signals, the problem remained open. The article considers the problem of restoring a random sequence from known mathematical expectation and correlation function. Such a model random sequence is constructed, in which the mathematical expectation and correlation function coincide with the given ones. The mathematical expectation and the correlation function are the simplest probabilistic numerical characteristics, but they do not uniquely determine the corresponding set of probability distribution densities that satisfy the conditions of normalization and consistency, provided that for each fixed integer value of the parameter, the random sequence is a continuous random variable. The article considers the restoration of a quasi-deterministic signal in stationary and non-stationary cases. For the stationary case, three examples are given for constructing a quasi-deterministic discrete signal n , provided that the spectral density has three different forms. For the non-stationary case, the corresponding quasi-deterministic signal was obtained for various cases of the spectrum. The use of a random function model determined by a finite number of parameters makes it possible to significantly simplify the analysis of applied problems, the solution of which is associated with differential equations with random coefficients, which are such quasi-deterministic signals. In this case, there is no need to use a complex apparatus of stochastic differential equations, since the solution of such an equation simply depends on random variables as on parameters.
Design of highly efficient water passage of pump-turbine
(Національний технічний університет "Харківський політехнічний інститут", 2023) Tynyanova, Irina; Rezvaya, Kseniya; Drankovskiy, Viktor; Savenkov, Dmytro; Tynianov, Oleksandr
The problem of the need to develop renewable energy sources as a way to save the energy supply and energy independence of Ukraine by changing the consumption of carbohydrates is considered. It is shown that the development of Ukrainian renewable energy must occur in parallel with the development of energy storage systems and balancing of the energy system. The most effective system for storing energy and balancing the energy system is pumped storage power stations (PSPS). The work shows that the design of a highly effective equipment of a hydroelectric power plant depends on the correct selection of the element geometry of the pump-turbine water passage. Therefore, it is possible to ensure the necessary level of energy characteristics of hydraulic equipment. A method of dimensionless average parameters was established, which allows even at the initial stages of designing new reversible hydraulic machines to determine the optimal geometry of the watter passage elements. This method showed good results during the numerical research of Francis hydraulic turbines at a wide range of heads, as well as reversible hydromachines at heads of 300–500 m. Using expressions that establish the connection of hydrodynamic characteristics with dimensionless complexes, three variants of the flow part of the high-pressure pump-turbines (ORO500) were investigated. Based on the obtained results, a significant influence of the geometry on the hydraulic indicators of the machine was noted. The distribution of energy losses in the inlet, blade system and outlet was analyzed. The greatest energy losses occur in the inlet of the pump-turbines. To increase the energy and kinematic indicators of the ORO500 pump-turbines, the geometry of the feed elements, as well as the spiral casing and stator, was changed. Variants for improving the parameters in the elements of the supply of the water passage of the pump-turbine are proposed.
Design specifics of a built-in diagnostic system for hydraulic machines
(Національний технічний університет "Харківський політехнічний інститут", 2023) Fatyeyev, Oleksandr; Fatieieva, Nadiia; Poliakov, Valerii; Shyian, Anatolii; Radchenko, Oleksandr
The basis for obtaining information about the object of diagnosis is technical diagnostic tools, which involve measuring operations of various parameters, the totality of which is the basis of the diagnostic process. Diagnostic tools are divided into external, portable (mobile) and built-in. Built- in technical diagnostic tools are considered. The built-in diagnostic system (BDS) is an autonomous complex for automatic checking of the degree of operability and serviceability of units and the hydraulic drive as a whole, which allows, within limited limits, to localize some faults based on the results of monitoring diagnostic and functional parameters in operational or special test modes, and the diagnostic results can be presented to the operator or accumulated for further processing. Compared to other built-in diagnostic tools, BDSs are the most complex and relatively new devices. They are in the process of development, prototyping, and experimental research. A set of diagnostic equipment was designed, namely: designing a unit of measuring instrumentation; designing a load device for diagnosing pumps and taking load characteristics directly at the facility. The designed set of diagnostic devices is used as an integrated diagnostic system (due to built-in sensors), as well as a separate diagnostic complex due to the ability to connect external sensors. The values of the diagnostic parameters measured by this complex can be recorded on an internal memory card or transferred via wireless Bluetooth to a PC or Android device (smartphone, tablet) for further processing. A study was also carried out to assess the strength of the hydrotester body using a computational and analytical method (using the finite element method in the Ansys Static Structural environment), which is equivalent to full-scale testing in terms of boundary conditions and achievable results. Based on the calculation results, it is possible to assert that the choice of material and structural dimensions of the designed device were chosen rationally.
Designing human-machine systems: transformation of a designer's thinking
(Національний технічний університет "Харківський політехнічний інститут", 2023) Mygal, Galyna; Protasenko, Olga
Industry 4.0 became a powerful impetus for the development of man-machine systems, which, on the one hand, increased their efficiency and reliability and, on the other hand, made them super-complex. As a result, this led to an increase in the complexity of human-machine system management and the manifestation of the human factor. The consequence is that, currently, the main cause of accidents and disasters is the human factor. Thus, the safety of human-machine systems largely depends on the person's psychological and physiological characteristics. The article shows that the study of a person's characteristics is the basis for the development of a human factor management system. The essential element of the human factor management system is the systemic ergonomics thinking of the human-machine systems designer. This type of thinking is formed as a result of training and the gradual acquisition of eco-ergonomic design skills. To explain the importance of the formation of eco-ergonomic thinking in humanmachine systems design, eco-ergonomic thinking evolution is presented in the work. Through the analysis of the sequence of the development of ergonomic thought, it is shown how the approach to ensuring the safety of human-machine systems has changed from the middle of the 20th century to the present. The next stage of the work was the analysis of eco-ergonomic, human-oriented, riskoriented, and strategic thinking. Based on the analysis results, a hierarchy of thinking types is built, and their role in the formation of systemic ergonomics thinking in human-machine systems designing is shown. The main feature of the designer's systemic ergonomics thinking is the priority of finding a solution to the problem in the system operation through research and analysis of human-machine interaction. Based on the obtained results, the importance of the formation and development of systemic ergonomics thinking is substantiated. It is shown how to implement the formation of a designer's systemic ergonomics thinking of human-machine systems through the training system.
Determination of characteristics of fatigue cracks growth in the axles of railway carriages
(Національний технічний університет "Харківський політехнічний інститут", 2023) Khomiak, Yuriy; Kibakov, Oleksandr; Gerasymov, Igor
Providing damage resistance is the most important requirement presented to railway axles. This paper provides a detailed review of the characteristics of resistance to fatigue crack growth in axles made of EA4T steel (25CrMo4). This steel is typical for axles of high-speed rolling stock. Resistance to fatigue crack growth is defined by the nature of the Paris-Erdogan curve da/dN=CKm, the parameters of which are the coefficient C and the exponent m. Determination of these parameters is based on the results of fatigue tests with the samples or with full-scale axles having cracks. The analysis of numerous scientific papers has shown that for the specified steel there is a significant scatter in the values of these parameters. This scatter is caused by a number of factors, the main of which are: the difference in test objects (from small samples of the SE(B) type to full-scale rolling axles 190 mm in diameter); the difference in loading methods (tension-compression, flat bending, circular bending); the variation of mechanical properties of EA4T steel. In the paper the models of surface fatigue crack geometry are analyzed and semi-elliptical shape of crack front line is selected as the most acceptable. The significant scatter in the values of the parameters m and C prevents to establish reliably the residual life of axles with cracks, which is an important characteristic for practical forecasting of axle survivability. The technique for parameters m and C optimization in view of semi-elliptical shape of the crack front line has been developed. The relationship linking the parameters m and C has been established. The method for determining the residual life of the axle by the criterion of non-destruction is proposed. The dependence between the residual life and the value of the parameters of the Paris-Erdogan equation in the development of fatigue failure is established. The procedure for axles monitoring timeframes setting to prevent their fatigue failure is discussed.
Development of a virtual device for controlling the condition of industrial units nodes using LabView tools
(Національний технічний університет "Харківський політехнічний інститут", 2023) Korzhov, I. M.; Mygushchenko, K. R.
This article is devoted to the research, construction, configuration and implementation of a virtual device for monitoring the condition of nodes of complex industrial units. Modern units used in heavy engineering require no less modern means of management, control and diagnostics of damage to such units and their components. The development of the structure of control tools is based on multi-level or multi-stage procedures of transformations of incoming measuring signals from aggregates. As the structure of the control device, a structure with a two-stage implementation of the spectral transformation of measurement signals – with a primary static transformation and a secondary static transformation – was chosen. The basis of the primary static transformation is the spectral transformation procedure based on the wavelet transformation. The basis of the secondary static transformation is the procedure of linear discrimination with the indication of the decisive rule. The article demonstrates and implements approaches to building a virtual device in terms of creating a block diagram, developing software, organizing the front panel of the device, setting up and carrying out simulation modeling for blocks of primary and secondary static transformations. The research uses the LabView platform. To prepare incoming measurement signals from nodes of industrial units, in the first block, the procedures of graduation, calibration and normalization of the target function are carried out. To receive input measuring signals from units of industrial nodes, the COM port of the computer is used which, according to the developed program, polls the COM port and inputs measuring signals to the primary static transformation procedure. The article describes a complete virtual control device that is formed and tested, which structurally contains all the blocks for achieving the control result and indicating the control result on the graphic interpretation of the computer.