bluuebunny/crossref_metadata_2025 huggingface dataset:
Transformation of Data Management in Russian Railways
Authors: Bystrickiy Dmitriy , Ermakov Sergey , Batalov Dmitriy
Published: December 2024

Abstract. The process of transformation of data management in JSC “Russian Railways”, the main directions of development of the Corporate Data Management System (CSMS), as well as prospects for further improvement of data management in the company are considered. The article uses methods for analyzing the experience of foreign railway companies in the field of data management, analyzing key trends in the development of the digital economy and state policy in the field of data management, as well as analyzing the results of the implementation of CSMS in JSC Russian Railways. The main tasks, structure, processes and technologies of CSMS are presented, as well as the main results of its implementation, including reducing the number of reports and employees involved in their formation. The key aspects of the formation of a culture of working with data in the company are considered, as well as the prospects for the development of CSM, including the expansion of data volume, the development of analytics tools and integration with other systems.
Access Control Using Artificial Intelligence: Opportunities and Risks
Authors: Blyum Vladislav , Grigor'eva Dar'ya
Published: December 2024

Abstract. In modern conditions, companies need to introduce new technologies in a timely manner and monitor compliance with information security requirements in order to effectively counter modern threats. Access control systems are one of the main tools that ensure an adequate level of information security at the enterprise and simplify control over the provision of access to the organization’s resources. The main goal: to explore the possibilities of using artificial intelligence for access control systems, highlighting its importance in the context of increasing the level of information security of the organization and the effectiveness of access rights management. Research method: analysis of modern tools and technologies, including artificial intelligence and large language models, as well as assessment of practical cases of AI implementation in access control systems. Both the advantages and risks associated with automated access control using AI are considered. Practical significance: the results of the work can be used by organizations to improve the security and efficiency of access management to information resources. The identified risks and recommendations for the introduction of AI technologies will allow companies to take a more conscious approach to improving information security processes.
Afterloading Brakiterapi Sistemlerinde Kaynak Kalibrasyonu Ve Radyasyon Güvenliği
Authors: Öztürk Dr. Nural
Published: December 2024

Brakiterapi, kanserli hücrelerin bulunduğu yere doğrudan ışın verebilmek için radyoaktif kaynakların doku içi, vücut yüzeyi ve boşluklarına yerleştirilerek yapılan tedavidir. Günümüzde, brakiterapi ile ışınlama, neredeyse tüm kanser bölgeleri için tedavinin temel bir parçası olarak kabul edilmektedir. İyileştirilmiş lokalizasyon teknikleri ve tedavi planlama sistemleri ile artık hassas ve tekrarlanabilir doz dağıtımına sahip olmak mümkündür. Terapötik uygulamalarda dozlar yüksektir ve reçete edilen dozdan sapma ciddi veya hatta ölümcül sonuçlara yol açabilir. Yüksek dozlar lokal olarak hedefe verilirken çevredeki normal dokularda hızlı doz düşüşü sağlanır. Küçük hacimlerde kısa sürede yüksek doza ulaşıldığı için kalite kontrolü oldukça önemlidir. Ancak, istenen klinik sonuçlar yalnızca iyi bir klinik ve dozimetrik uygulama ile, yani kısaca ayrıntılı Kalite Kontrol prosedürlerini içeren kapsamlı, uygulanabilir ve tekrarlanabilir bir Kalite Güvence (KG) programının uygulanmasıyla elde edilebilir. Bu KG’ nin en temel unsurlarından birisi de kaynak bilgilerinin doğruluğunun tespit edilmesi ve Tedavi Planlama Sistemine (TPS) girilmesidir. Bu kalibrasyon için merkezde mevcut olan düzeneğe göre ihtiyaç duyulan ekipmanların (Kkuyu-tipi iyon odası, jig fantom, özel kalibrasyon fantomu, uygun iyon odaları ve elektrometreler) doğru çalışıyor olması kaynak kalibrasyonu için en gerekli unsurlardan biridir. Ayrıca görev dağılımının belirlenmesi, sorumlu olacak kişilerin yetkilendirilmesi, ilgili tüm personelin görevleri için uygun şekilde eğitilmesi KG için gereklidir. Bunlara ilave olarak merkeze özgü kalite kontrol ve radyasyon güvenliği prosedürünün mevcudiyeti doğru ve kaliteli uygulama yapmanın temelidir.
Time-optimal trajectory planning for a six-degree-of-freedom manipulator: a method integrating RRT and chaotic PSO
Authors: Wang Zuoxun , Pang Chuanzhe , Sui Jinxue , Zhao Guojian , Wu Wangyao , Xu Liteng
Published: December 2024

This study proposes an innovative algorithm based on a hybrid optimization strategy, integrating the rapidly-exploring random tree (RRT) and an improved particle swarm optimization (PSO) method to address the time-optimal trajectory planning problem for six-degree-of-freedom robotic arms. The proposed approach emphasizes obstacle avoidance and motion smoothness. RRT is utilized within a dynamic three-dimensional environment to rapidly generate an initial collision-free path. Subsequently, improved PSO enhances global search performance by introducing a multi-source chaotic mapping-based population initialization strategy, dynamically adjusted inertia weights, and nonlinear learning factors. These enhancements effectively mitigate the limitations of traditional PSO methods, which are prone to premature convergence in complex optimization problems. Furthermore, the proposed 3-5-3 polynomial interpolation method significantly smooths the trajectory, reducing fluctuations in velocity and acceleration, and thereby improving the precision and energy efficiency of trajectory planning. Experimental results demonstrate that the proposed algorithm outperforms existing methods, such as the improved RRT and improved non-dominated sorting genetic algorithm, across multiple metrics. Notable achievements include a reduction of total motion time by approximately 21%, improved stability in robotic arm motion, and enhanced adaptability to dynamic environments. Particularly, the method achieves superior trajectory diversity and uniformity through joint optimization of multiple chaotic sources, overcoming the inherent limitations of single chaotic mappings. This research expands the application scenarios of RRT and PSO and provides a novel solution for intelligent control and real-time planning of high-degree-of-freedom robotic arms.
Nuances and meaning of the concept trust in and for academic development practice and practitioners
Authors: Ravhuhali Fhatuwani , Mboweni Hlayisani HF.
Published: December 2024

The study covers AD practitioners' definitions of trust, levels of trust, and responsibilities in developing trust with university academics. It also studies how culture affects trust and how AD practitioners might build trust amongst university lecturers and institutions. Thematic and content analysis were performed on six AD practitioners selected for sampling. The findings show that trust can mean self-confidence, being respected, and doing professional work. AD professionals express self-confidence in their competence and trust in their colleagues. Having one's contributions recognised and appreciated fosters trust and belonging. Professional obligations require trust in the system and the conviction that everyone is contributing to similar aims. The survey also finds scepticism, with some practitioners perceiving academic progress as a burden. The report emphasises the repercussions of broken trust in collaborative efforts and recommends university workshops to establish trust, meaningful participation, and community among AD practitioners and university academics. To boost student learning, AD practitioners must create trust, according to the report. It suggests studying trust-building tactics to create collaborative connections and overcome faculty resistance to academic advancement.
Exploring the impact of the Extended Curriculum Programme (ECP) as a crucial motivating landing space
Authors: Mokganya Georgina , Zitha Innocent
Published: December 2024

The smooth transition of students into higher education is crucial for laying a strong foundation for success at the university level. This paper investigated students’ perceptions and responses to enrolling in an Extended Curriculum Programme (ECP) and lecturers’ efforts to motivate students and understand the factors that may hinder student success. To achieve this, the research utilised a mixed methods approach, incorporating both qualitative and quantitative dimensions. The researchers purposefully selected 150 ECP students enrolled in the 2024 academic year. Data collection involved the use of free listing techniques and semi-structured interviews, which allowed for a comprehensive understanding of the students' experiences. The collected research data was organised, transcribed, and analysed using thematic analysis, ensuring a systematic and in-depth exploration of the data. Additionally, the findings were statistically analysed using Microsoft Excel to compare the challenges faced based on gender and age, providing a nuanced understanding of the factors influencing student transition. The students, while enthusiastic about their university experience, also expressed feelings of being lost and overwhelmed during their transition. Many students, particularly those who linked their early academic performance to future opportunities, felt unprepared for independent study at the university, which was distressing. Ignoring such experiences and the lack of a sense of belonging can hinder students' academic success. Therefore, it is crucial for lecturers to identify students’ emotions early and implement supportive strategies, such as a well-planned orientation program, recognition, and rewards for high-achieving students. The paper recommends strategies and techniques that should be implemented to facilitate a smoother transition for students into higher education.
The role of 4IR technologies and organizational culture in enhancing manufacturing supply chain performance
Authors: Mabotja Tshepo
Published: December 2024

This study seeks to create a model for the management of the steel production supply chain in South Africa amid the Fourth Industrial Revolution (4IR), tackling persistent interruptions and delays within the supply chain despite current models. A mixed methodology was utilised in the model's development. The qualitative component entailed a Delphi research corroborated by literature to ascertain pertinent hypotheses, whereas the quantitative component validated the model through structural equation modelling (SEM) utilising SmartPLS software. The research delineated a seven-construct framework comprising cooperation, integration, communication, supply chain structure, Fourth Industrial Revolution technology, organisational culture, and trust. The amalgamation of these designs proved enough for improving the efficacy of the steel production supply chain. The research revealed that the use of Fourth Industrial Revolution technologies and the cultivation of a conducive organisational culture are essential for effective supply chain management in the steel manufacturing industry. The research presents a detailed model that facilitates the planning and organisation of steel industry supply networks in South Africa. This approach underscores the necessity of a cooperative organisational culture, client contentment, and the incorporation of Fourth Industrial Revolution technologies. Steel industry stakeholders are urged to implement adaptable supply chain frameworks (lean, agile, leagile) based on project goals. This study enhances theoretical frameworks by highlighting essential features that have not been previously incorporated into supply chain management models for the steel sector, including the integration of Fourth Industrial Revolution technology and organisational culture. It provides actionable insights for stakeholders in steel manufacture, enhancing supply chain performance via the proposed paradigm. The research methodology improves comprehension of supply chain management within the framework of the Fourth Industrial Revolution (4IR).
The adverse psychosocial effects of post-Covid-19 in dismantling family structures leaving children heading families in Mavalani village, Limpopo Province
Authors: Thema Jeaneth Reanetse , Mphahlele Kamogelo Meriam , Ritshuri Ntshuxeko Hennie , Ramanyimi A.P. , Mushwana Mercy , Chueng Maphuti
Published: December 2024

Globally, there were 5 million COVID-19 deaths between March 2020 and October 2021, and approximately 5·2 million children lost a parent or caregiver because of COVID-19-related deaths. This has left so many orphaned children that had to navigate life without parental supervision. This paper aims to demonstrate the adverse social effects of covid-19 in the lives of children in child-headed families in a small village called Mavalani in Limpopo province, South Africa. We employed a qualitative study utilizing an explorative research design to get deeper knowledge of the adverse effects of Covid-19 on child-headed families in Mavalani village. Purposive sampling, which is a non-probability sampling technique was used to purposefully select the participants that are suitable for the research study. A sample size of 10 teenagers aged 13-17 years old were randomly selected within the population of child-headed families in Mavalani village. Thematic data analysis was utilized to analyse the adverse social effects experienced by child-headed families because of covid-19 parental death. Main findings of the study demonstrate that the COVID-19 pandemic has had a profound impact on family dynamics, resulting in the loss of parents and leaving children to care for their siblings in child-headed households. These children often face discrimination and social isolation due to the stigma associated with being a part of a child-headed family, leading to feelings of anxiety when interacting with their peers. Taking on the responsibilities of a parent at a young age has also had a significant impact on their childhood experiences and overall well-being.
Bridging causal explanation and predictive modeling: the role of PLS-SEM
Authors: Lin Mei-Lan , Huynh Linh Lan
Published: December 2024

Partial Least Squares Structural Equation Modeling has gained considerable attention across diverse academic fields, including business, social sciences, marketing, and management. A key challenge in utilizing PLS-SEM is balancing explanatory and predictive power when selecting the most suitable model from competing alternatives. This paper explores the effectiveness of various quality criteria for evaluating causal-predictive models, with a focus on resistance to change in Vietnamese SMEs. The study emphasizes the importance of both in-sample and out-of-sample predictions, using metrics such as R², BIC, AIC, Q², RMSE, MAE, and CVPAT. The findings reveal that traditional criteria like R² may not be sufficient for identifying the best model, while PLSpredict, CVPAT, BIC, and AIC offer superior performance in determining the optimal balance between explanatory and predictive capabilities. These insights provide practical implications for researchers and practitioners, highlighting the need to tailor model selection to specific objectives, such as theory development or real-world forecasting. For practitioners, the study underscores the benefits of leveraging simpler, more generalizable models for robust decision-making in dynamic or resource-constrained environments.
Exploring Generation Z's Influence on Tourism Industry: A Bibliometric Analysis
Authors: Anward Ryan Juminta , Simon Helene Elisabeth , Nurhidayati Sri Endah
Published: December 2024

Generation Z plays a crucial role in shaping the tourism industry, distinguished by its unique characteristics and strong digital expertise. Using bibliometric analysis, this study examined 192 publications indexed in the Scopus database between 2018 and 2024. The findings indicate an increasing interest among academics after 2020, with a focus on collaborative efforts and global contributions. Key themes include social media, sustainability, and virtual reality, reflecting evolving research directions in Generation Z's travel preferences. Based on these findings, future studies should explore longitudinal analyses and cross-cultural comparisons to refine tourism strategies, leveraging innovative technologies and marketing approaches to increase the  engagement with Generation Z travellers.
EXPLORING THE PERCEPTIONS OF GROWTH: A GROUNDED THEORY CASE STUDY FROM TÜRKIYE
Authors: Yılmaz Fındık Leyla
Published: December 2024

This study examines students' perceptions of personal growth by applying growth mindset principles through a grounded theory approach. Using qualitative data collected from interviews, the research focuses on beliefs about effort, responses to failure, feedback, and the malleability of intelligence. A theoretical sampling strategy, integral to grounded theory methodology, was employed to select 32 students from the Faculty of Education, including 9 second-year, 19 third-year, and 4 fourth-year students. The findings reveal four key themes: Effort-Driven Development, emphasizing the primacy of effort over innate ability; Resilience and Learning from Failure, which highlights failure as an opportunity for growth; Openness to Feedback as a Development Tool, demonstrating the value placed on feedback for self-improvement; and A Dynamic View of Intelligence and Abilities, reflecting a belief in the evolving nature of intelligence. These insights enhance our understanding of how growth mindset principles manifest in educational contexts, offering practical implications for teaching practices and organizational strategies aimed at fostering personal development.
EXAMINING THE IMPACT OF AI-POWERED WRITING TOOLS ON INDEPENDENT WRITING SKILLS OF HEALTH SCIENCE GRADUATES
Authors: Milton Cynthia , Vidhya Lokesh , Thiruvengadam Gayathri
Published: December 2024

The level of reliance on AI-Powered Writing Tools (AI-PWT) profoundly impacts the independent writing skill of English as Second Language (ESL) learners. The present study explores the familiarity and utility of two different types of AI -Powered Writing Tools  (Independent Writing with AI editing assistance; Generative writing with AI assistance) among ESL health science graduates and to understand the role of these tools in shaping their independent writing skills.  Method: The study adopted a survey technique to understand the knowledge, attitude and utility of AI-powered writing tools among 309 Health Science graduates from a South Indian private Medical University. Result: The findings showed the overall frequency distribution of the participants’ level of knowledge had a higher score range of 14-20 in 213 (68.9%) samples.  Although 215 (70%) were familiar on using AI-PWT to improve vocabulary and grammar, around 17-19 % were uncertain about receiving real-time writing feedback to optimize the content. 199 (64%) expressed a positive perspective in using AI-PWT. Around 214 (69.3 %) took assistance from AI-PWT for generative writing purposes than revising the independently written content. In practice, only 64 (20.7 %) received feedback to refine the vocabulary and 60 (19.4%) to revise grammar, indicating an inclination for more generative writing with AI utility than Independent Writing with editing assistance. Conclusion: AI-Powered Writing Tools are well-recognised and powerful writing assistance to help students with their academic writing. However, relying on these tools only for generative purposes could significantly affect independent writing.  The study insists on the need for teacher-guided assistance to train students to adopt the right tool that could best serve as a collaborative writing assistant adhering to the ethics.
Position control systems with friction compensation for servo pneumatic actuators
Authors: Nikitin Artur , Levchenko Oleh
Published: December 2024

This work is devoted to the development of control systems for a tracking pneumatic actuator, taking into account the current position of the working body of the actuator and the amount of friction in the friction pairs of the actuator. Implementing the positioning of a pneumatic actuator is a complex technical task, but at the same time extremely relevant, since industrial systems of modern production require the performance of technological operations not only with high speed but also with high accuracy of positioning the working body of the actuator. The paper also considers control systems for pneumatic actuators based on the position of the working body, taking into account the nonlinearity of motion caused by friction forces in the pneumatic actuator. Friction in the contact pairs of pneumatic actuators adversely affects the operation of the actuators, especially taking into account the dependence of friction on ambient temperature, the surface condition of the contact pairs, the availability and quality of lubricants, etc. The study demonstrates existing control systems and implemented static and dynamic models of friction compensation and the impact of such models on the accuracy and controllability of systems with different types of regulators and implementation schemes, including proportional distributors with analog control and high-speed direct-acting distributors.  The paper analyzes positioning systems with the ability to regulate the inlet pressure and the impact of such system solutions on the system rigidity and its performance. The paper formulates a goal for further research and identifies a list of tasks necessary to achieve the goal set in the paper. The paper also presents a design solution for a test bench with the ability to implement adaptive control of the actuator force depending on changes in the operating parameters of the technological operation and changes in the parameters of the pneumatic system as a whole.
Analysis of tearing test results for joining tips of metal-composite joints
Authors: Taranenko Igor
Published: December 2024

Background: Designing highly loaded joints of metal-composite ends of aerospace engineering units meets the problem of assessing their bearing capacity, checking the adequacy of created mathematical calculation models to real testing results, and studying the dependence of the production technology of such joints on their final load-bearing capacity.
Objective: The study of the dependence of the load-bearing capacity of "metal-composite" joints on the technology of their creation and the evaluation of the quality control process of combined joints with cylindrical transversal microelements and the adhesive bond between connecting parts was chosen as the goal of the research.
Methods: The joint of a flat metal tip with a carbon fiber part using transverse cylindrical pins and adhesive is considered as an object of research. Transversal pins of different diameters are inserted into the composite package. Various technological processes of preparing the surface of the metal part and pins for subsequent adhesive joining are considered in order to maximize the adhesion between the polymer binder and the metal elements of the joint. Also, for a more rational distribution of stiffness and corresponding stresses in the parts, the metal tip has a variable stepped thickness along the length of the joint.
Results. As the results of the study, the theoretical failure load of the joints was evaluated and compared with the results of experimental tests. Also the technological process of preparing the surface of the metal part and the pins for further joining with the composite part is recommended, which ensures maximum adhesion between the joining parts.
A conclusion was made regarding the diameter of the pins and the shape of the profiled metal part, which ensure the maximum load-bearing capacity of the connection.
The types of joint failure were analyzed and conclusions were drawn regarding changes in the technology of surface preparation, the layout of the pins and the choice of their diameter.
Conclusions: As conclusions, recommendations were formulated regarding a certain technology for surface treatment of a metal part, which guarantees maximum adhesion between the metal part, pins and composite, and actual processes of quality control of "metal-composite" joints with transversal microelements were selected.
Finite-element two-stage modelling of stress-strain state parameters of a planar truss with parallel chords
Authors: Omelian Maksym
Published: December 2024

This paper investigates a planar truss with parallel belts made of VCt3ps steel. The stress-strain state (SSS) of such a truss is studied using a two-stage numerical modelling method based on the application of LIRA-SAPR 2016 R5 and ANSYS Workbench 14.5 software packages.The main problem is to improve the accuracy of determining the parameters of the stress-strain state of flat trusses, which will reduce their material consumption and design complexity. This will facilitate the optimization of manufacturing processes in construction and engineering.The paper proposes a two-stage modelling methodology that involves the use of two software packages. At the first stage, a finite-element model is created in LIRA-SAPR, where the preliminary parameters of the SSS are determined. At the second stage, this model was detailed in ANSYS Workbench. Critical zones in the truss nodes where stresses are maximum were identified, which is key for further design.The modelling efficiency is due to the integration of data from both software packages. This makes it possible to compensate for the limitations of each of them separately, in particular in modelling nodes with stress concentrations. The methodology provides visibility of the stress-strain state parameters, which contributes to the effective analysis of the data obtained.The work demonstrates the effectiveness of a two-stage approach to modelling the stress-strain state, which has made it possible to achieve efficiency in determining the parameters of the stress-strain state of a truss. The combination of LIRA-CAD and ANSYS allows to effectively take into account both the overall strength characteristics of the structure and local deformations and stress concentration zones.The results of the study can be applied in the construction of industrial and public buildings, bridges, as well as in other industries, including mechanical engineering, where parallel girders are used. The methodology ensures the optimisation of material costs and labour costs during design, which is critical for large-scale engineering projects.
Hybridized Triply Periodic Minimal Surface Recuperators in CSP Super-Critical CO2 Recompressed Brayton Cycles – Review and Avant-Garde Pro-Spects
Authors: Letlhare-Wastikc Kabo , Yang Xinle
Published: December 2024

Recompressed sCO2 Brayton Cycles (RCBC) are topical in the narrative of sustainable energy conversion and are considered to be at 80 % technology readiness level, but still open to thermal efficiency (ηth) and levelized cost of energy (LCOE) enhancements. However, the lack of rigorous academic engagement in the specific nexus of concentrated solar plant (CSP) RCBCs and Triply periodic minimal surface (TPMS) recuperators may be veiling the honey pot. This study surveys data over two decades around academic and research institutions on the history and trends of solar RCBCs and how recuperators contribute to their thermal and economic efficiency. Findings show that many theoretical studies on the RCBC exist, but among RCBC – CSP demonstration plants, there is a total of three (3) ongoing full scale testing stations in the US, EU and China and a couple others still in the construction and initial commissioning stage. The highest reported ηth is 54 % and the lowest LCOE is 0.059 $/kWh. Among the existing test stations worldwide, most use printed circuit heat exchangers (PCHE) recuperators, despite numerical studies presented in this study proving that TPMS recuperators are more effectual on both thermal, hydraulic and LCOE per-formance. As a result, this study has made a strong case in proposing that better prospects may lie around TPMS hybridization of recuperators retrofitted into CSP RCBCs. The authors have strengthened their case by presenting literature evidence on the availability sCO2 compatible alloys, maturity of TPMS manufacturing technology, cost and time effectiveness of their fabrication.
Simulation Study and Proper Orthogonal Decomposition Analysis of Buoyant Flame Dynamics and Heat Transfer of Wind-Aided Fires Spreading on Sloped Terrain
Authors: Su Chenyao , Hu Yong , Ma Yiwang , Yang Jiuling
Published: December 2024

The wind and slope are deemed to be the determinant factors driving the extreme or erratic spread behaviour of wildfire, which however has not been fully investigated, especially to elaborate the mechanism of fire spread associated with heat transfer and fluid dynamics. A systematic study is therefore carried out based on a physical-based simulation and Proper Orthogonal Decomposition (POD) analysis. Results show that compared to the wind, the slope plays a more profound effect on the fire structure; with the increase of slope, the fireline undergoes a transition from a W-shape to the U- and pointed V-shape, accompanied by the stripe burning zones, indicating a faster spread but incomplete combustion. The wind effect is distinguished to mainly induce the turbulent backflow ahead of the fire front, while the slope effect promotes the convective heating by the enhanced slant fire plume. Different mechanisms are also identified for the heat transfer ahead of fireline, i.e., the radiative heat is affected by the combined effects of flame length and view angle, and in contrast, the convective part of heating flux is dominated by the action of flame attachment, which is demonstrated to play a crucial role for the fire spread acceleration at higher slopes (>20∘). The POD analysis shows the distinct pattern of flame pulsating for the respective wind and slope effects, which sheds light on modeling the unsteady features of fire spreading and reconfirms the necessity of considering the different effects of these two environmental factors.
Population parameters of the red-bellied piranha Pygocentrus nattereri (Kner, 1860) (Characiformes: Serrasalmidae) of the São Miguel River, Rondônia state, Brazil
Authors: Dias Jordy de Oliveira , Sant'Anna Igor Rechetnicow Alves , Bezerra Neto Eloi Bispo , Sousa Raniere Garcez Costa , Dantas Filho Jerônimo Vieira
Published: December 2024

In this study, the structure and distribution of Pygocentrus nattereri populations in the São Miguel River basin, Rondônia state, Brazil, were evaluated. From August 2020 to July 2021, monthly fisheries were carried out, using gillnets with meshes ranging from 40 to 160 mm between opposite knots, which were in place for 48 hours and inspected at 6 am; 12 am; 6 pm and 12 pm. Growth parameters and mortality were estimated using length-frequency data. The population values ​​found for P. nattereri were L∞ = 29 cm, k = 0.55 .year-1, with mortality values: M = 0.57, Z = 0.98 and F = 0.41. year-1. The relationship between weight and length was described by Wt = 0.0372.Lt2.983. The data obtained indicates that the P. nattereri stocks in the study region are not overfished; therefore, measures and actions for a fishing management plan for P. nattereri populations must be implemented for the studied river region in order to prevent the increase in these populations and preserve the other species of fish commercial interest.
DETERMINING THE STATE VARIABLES OF A DISCRETE PNEUMATIC DRIVE BY USING THE SECANT METHOD WHEN LINEARIZING A MATHEMATICAL MODEL
Authors: Krutikov G. , Borodin D.
Published: December 2024

The pneumatic drive as a thermodynamic system is described based on the principles of "thermodynamics of a body of variable mass". In describing thermodynamic and gas-dynamic processes in pneumatic drives, two scientific schools have developed: researchers of the first school represent processes in the cavities of the drive as polytropic processes with a variable polytropic index, and the second consider processes based on the equation of energy (heat) balance of the gas-pneumatic drive in an open space. The authors investigate a nonlinear mathematical model obtained on the concepts of the second school. In the cycles of reducing the number of independent parameters that determine the nature of the transient process in the drive, a transition to a dimensionless form of equations is carried out based on the principle of minimizing dimensionless complexes (dynamic similarity criteria) that determine the nature of the transient process. The task of linearization of the nonlinear model was set with the purpose of obtaining analytical expressions for all state variables based on the linear model, which will allow avoiding the numerical step methods of integration of the original nonlinear model in calculations. It is shown that the replacement of nonlinear dependencies by the first terms of their expansion in a Taylor series (the tangent method), which is practiced for servo hydraulic pneumatic drives, leads to large errors in relation to discrete drives. The proposed linearization by the secant method with the choice of the optimal form of the sowing allowed to significantly increase the calculated accuracy of the linear mathematical model. and obtain the state variables of the pneumatic drive in analytical form.
The calculations performed using the second-order linear model convincingly indicate that it is quite adequate to the calculated accuracy of the nonlinear mathematical model. In the entire range of the most probable parameters, the calculated accuracy of the second-order mathematical model is quite sufficient for practical use. Thus, the need to use step-by-step numerical methods for integrating the equations of a nonlinear model and organizing the computational process on a computer is eliminated.
EXPERIMENTAL STAND FOR STUDYING LOCAL CONDITIONS OF TRANSIENT HEAT TRANSFER
Authors: Selikhov Yu. A. , Mironov A. M. , Gorbunov K. O. , Ris V. G.
Published: December 2024

An experimental setup has been designed to study local conditions of non-stationary heat exchange during cooling of a high-temperature surface with a sprayed liquid: from nozzles of various modifications (including sprayers); water-air; steam-air; steam-water; superheated liquid; water with different concentrations of surfactants.
An analysis of scientific sources has determined a research methodology that will allow the study of the influence of irrigation density, surface temperature, degree of liquid underheating, its velocity and angle of flow onto the surface, taking into account the possibility of implementing a change in the determining factors in the range of their corresponding real values ​​in natural energy and metallurgy facilities and the task of selecting a method for identifying the boundary conditions of heat exchange.
We have not come across any studies of heat exchange intensity as a function of underheating of sprayed liquid – water with different concentrations of surfactants at different local irrigation densities and surface temperatures in scientific publications. Therefore, these studies, as well as the development of effective cooling systems or determination of the thermal state of objects under various external influences, are of primary importance to us.
In order to implement our planned research program, in addition to developing a method for identifying the boundary conditions of heat exchange, it was necessary to solve a number of special problems associated with determining the operating parameters of the cooling medium. These include the local irrigation density and the velocity of the dispersed medium at the surface of the thermal probe.
For reliable determination of local irrigation flow rate, as well as determination of the dispersed composition of drops, the pulse counting method, which has the possibility of practical implementation in our country, should be used.
To determine local conditions of non-stationary heat exchange, we have developed a scheme for measuring the EMF of temperature detectors installed in the body of the rod of the thermal probe, and also selected high-speed digital recording equipment.
The solution of the inverse problem of heat conduction will allow us to establish the degree of influence of practically all factors indicated as determining ones.
INVESTIGATION OF THE DENSITY OF CCCM AND ITS INFLUENCE ON SPECIFIC VOLUME ELECTRICAL RESISTIVITY
Authors: Hurin I. , Nevlyudov I. , Ovcharenko V. , Tokarieva O.
Published: December 2024

This article investigates the structure and properties of carbon-carbon composite materials (CCCM), where the carbon matrix is formed by the deposition of pyrolytic carbon in the porous volume of a carbon fiber preform using thermogradient gas-phase pyrolysis densification technologies.  
The results of studying the apparent density of CCCM by hydrostatic methods and its influence on the specific volume electrical resistivity of the material are presented. The conducted study established that the specific volume electrical resistivity of CCCM significantly depends on a number of factors, one of which is the material density. An increase in the apparent density of the material leads to a decrease in its porosity, which, in turn, affects the decrease in electrical resistance. It is emphasized that density control becomes a key factor in ensuring optimal electrical conductivity of carbon-carbon composite materials.
It is shown that the densification of CCCM significantly improves the structure of blanks and crucibles, increasing their physical and operational characteristics. This makes them more suitable for use in high-temperature conditions, aggressive environments, in the production of heat-resistant components and other high-tech areas.
Repeated densification of CCCM revealed a significant impact on the quality of the material. It is shown that an increase in density after additional densification leads to a decrease in porosity, improvement of mechanical properties and a change in the pore distribution in the material, which positively affects its porosity and strength.
Bench tests of model samples made of CCCM showed that an increase in the apparent density of the material leads to a decrease in its electrical resistance. To ensure control in industrial practice, an effective and affordable method for assessing the degree of completion of crystalline transformations and determining the degree of graphitization during high-temperature treatment of carbon materials is recommended to compare the specific volume electrical resistivity of the working sample with the reference one.
The importance of controlling the parameters of density, porosity, and electrical resistance to optimize technological processes and ensure high quality of final products is emphasized. The obtained data can be useful for applications in various industries.
THE INFLUENCE OF BETA-CAROTENE AND CHLOROPHYL CONCENTRATION ON THE OXIDATION RATE OF THEIR OIL SOLUTIONS
Authors: Petik I. P. , Litvinenko E. A. , Ponomarova M. S. , Dikhtyar A. M. , Andrieieva S. S. , Balandina I. S. , Kariyk A. O.
Published: December 2024

The object of the study is the induction period of accelerated oxidation of oil solutions of fat-soluble dyes chlorophyll and beta-carotene. The effect of the content of fat-soluble dyes on the induction period of accelerated oxidation of their solutions in sunflower oil was studied. The peculiarity of the work consists in establishing the approximation graphical and mathematical dependencies of the induction period of accelerated oxidation of refined sunflower oil on the combined content of chlorophyll and beta-carotene. This is of interest for predicting the shelf life of oil solutions of the specified fat-soluble dyes. It was determined that chlorophyll A has virtually no prooxidant effect provided that its content in the oil solution is up to 0.05 g/l. The content of chlorophyll A at the level of 0.10 g/l leads to a decrease in the induction period by 14 %; 0.20 g/l – by 36 %; 0.30 g/l – by 48 %. The content of beta-carotene at the level of 0.10 g/l leads to an increase in the induction period by 35 %; 0.20 g/l – by 47 %; 0.30 g/l – by 54 %. The content of 0.10 g/l beta-carotene and 0.05 g/l chlorophyll A in the fat system leads to a decrease in the induction period of accelerated oxidation by 8.4 % compared to an oil solution of 0.10 g/l beta-carotene without chlorophyll A. The obtained data are explained by the fact that there is a compensating effect of the antioxidant beta-carotene on the prooxidant action of chlorophyll A in the oil solution. A special feature of the obtained results is the possibility of predicting the shelf life of oil solutions of fat-soluble dyes. From a practical point of view, the results of the studies allow us to substantiate the composition of fat systems taking into account the joint features of the reactivity to oxidative destruction of chlorophyll and beta-carotene. The applied aspect of using the scientific result is the possibility of expanding the range of fat products of increased nutritional value with different contents of chlorophyll and beta-carotene.
CALCULATION PROGRAM OF THE ABSORPTION PROCESS IN NITRIC ACID PRODUCTION
Authors: Puhanovskyi O. V. , Shutynskyi O. H.
Published: December 2024

The modern technological process is a product of design and modeling. Verification of theories and technical solutions can be carried out not on existing equipment but on mathematical models, by means of calculations. This increases the safety of research activities and speeds up the design process. For large research institutions and manufacturers, it is advisable to use specialized software such as MatLab, ASPEN or SimSci. Such environments have a large number of libraries and applications, which make them multifunctional. At the same time, the vast majority of users use only a small number of narrowly specialized functions that correspond to the direction of their activity.
Mastering programming skills has become an integral part of modern education. Creating calculation programs based on mathematical models is not a difficult task for scientists. The rapid development of programming languages and technologies allows choosing the most appropriate ways of creating programs. According to experts, C# has been in the top 5 popular programming languages for many years. The use of this language is closely related to the .NET technology, which is intended for creating cross-platform applications. Microsoft Corporation provides the possibility of free use of its product MS Visual Studio, which also includes C#.
The article describes a program created for use in researching the operation of an absorption column for the absorption of nitrogen oxides in the production of nitric acid. When developing the program, a standard calculation algorithm was used, according to which industrial devices operating in Ukraine were calculated. The algorithm also takes into account the latest information on the influence of technological parameters and physico-chemical processes. The program is created with a minimalistic interface and data entry options both from the program window and from a text file. The results of calculating the influence of oxygen addition on the concentration of nitrogen oxides in the discharge gas are given. The main purpose of the program is to study the operation of the column as an object of automation. The proposed program can be supplemented with new options, such as automatic calculation of gain coefficients for specified channels, batch processing based on data from a file, and others. Also, the program can be used for teaching students and performing research.
DEPENDENCE OF QUALITY INDICATORS OF EXTRUDATE ON RAW MATERIAL CHARACTERISTICS
Authors: Stankevich S. V. , Omelchenko S. B. , Kotlyar O. V. , Bakirov Mushfik Panakh ogly , Zhulinska O. V. , Ashtaeva N. L.
Published: December 2024

The way to solve the problem of correcting the technological indicators, especially porosity and moisture content in extruded protein-fat systems based on soybean, rapeseed, hemp and corn groats is considered. The peculiarity of the work is the substantiation of the rational ratio of the content of moisture and lipids in the raw components of the extrudate, which is an important aspect of rationalizing the composition and improving the texture of innovative extruded products based on the specified raw materials.
The object of the research is the technological indicators, in particular the porosity and humidity of the extruded protein-fat system, depending on the moisture and lipid content of the raw components. A rational ratio of moisture content (10.5...12.5 %) and lipids (3.5...5.0 %) in the raw material for the extruded protein-fat system has been established.
The physico-chemical and technological indicators of the extruded protein-fat system of the developed composition were compared with the same indicators of the existing similar product (extruded multi-cereal flakes). The indicators of the composition of the developed extract correspond to the indicators of the comparison product in terms of lipid content (4.4% vs. 4.6 %), moisture and volatile substances (8.5 % vs. 9.1 %). The indicators of the developed extrudate exceed the indicators of the comparison product in terms of crude protein content (29.0 % vs. 8.2 %) and porosity (130 % vs. 105 %). The fiber content in the developed product is lower than the comparison product (14.2 % versus 56.1 %). The obtained data are explained by the fact that a complex of components was used, some of which are production waste, with reasonable moisture and lipid content, which affected the positive technological characteristics of the extrudate. An applied aspect of using this scientific result is the possibility of rationalizing the process of extruding oilseed meal to achieve the desired texture, porosity and stability of the lipid component of the product.
PARAMETERS OF HOT WATER SUPPLY HEAT EXCHANGERS FOR HEAT STATIONS OF INSULATED BUILDINGS AT ONE-STAGE CONNECTION SCHEME
Authors: Aleksakhyn A. A. , Kruhliakova O. V. , Boblovskyi A. V. , Tiutiunyk L. I.
Published: December 2024

The peculiarities of functioning of centralized heat supply systems of residential microdistricts at carrying out works on ‘insulation’ of buildings in operation, namely, parameters of operation of hot water supply heating units are considered. The influence of the heating load reduction due to the works on increasing the heat transfer resistance of the building structures on the flow rate of network water and heat exchange area of hot water supply heaters has been analyzed. Estimates are made for conditions of use of one-stage parallel scheme connection for heat exchangers to heat distribution networks. The known relations for such most widespread in heat supply systems heat exchangers as plate apparatuses are used at calculations of a heat transfer surface. The range of change of the heat transfer surface of hot water heaters and the flow rate of network water depending on the ratio of the maximum heat loads of hot water supply and heating and the degree of insulation efficiency of the building is determined.
Formulas for determining the parameters of hot water supply heat exchangers are proposed. The formulas are valid in the range of reduction of heat consumption for heating of the building from 0 to 35 %. Assessment of the heating load reduction is performed on condition that the thermal modernization of a building constructed in accordance with the building requirements in force several decades ago provides modern requirements for the thermal resistance of building structures. The temperature of water in the heating system of the insulated building is determined depending on the building insulation efficiency, provided that the water flow rate through the heating system of the building before and after its insulation is unchanged. The range of variation of the ratio of hot water supply and heating heat loads accepted for consideration is 0,6–1,2.
The obtained results can be used at comparison of connection schemes of heat exchangers for hot water heating for installation on individual heat points of insulated buildings.