Advances in Science and Technology Vol. 181

Abstract: This work presents a methodology for extracting NVH-relevant, machine-learning–ready features from CMM-based gear inspection reports available only in PDF format. Although raw point-cloud measurements are not available, the approach demonstrates how curve-level geometric information—such as profile and lead deviation, pitch behavior, and runout shape patterns—can be interpreted directly from the plotted diagrams. These curve-derived descriptors capture qualitative shape phenomena that are not represented in tabulated tolerances and can be transformed into structured numerical features suitable for future correlation with NVH indicators such as transmission-error variability or tonal-noise risk. The method enables digitization of historical PDF-only metrology archives and provides a foundation for data-driven NVH assessment and predictive quality workflows. Similar approaches that extract geometric and dynamic features from profile or error curves have been shown to reveal excitation mechanisms underlying transmission error and tonal noise generation.

Abstract: Accurate, non-destructive assessment of watermelon ripeness remains a significant challenge in horticultural production, particularly under field conditions where traditional visual and tactile evaluation methods are subjective and often inconsistent. Although mechanical, acoustic, and spectroscopic techniques have demonstrated promising performance, their reliance on controlled laboratory environments limits their practical applicability in real-world agricultural settings. This study presents a field-deployable, AI-assisted computer vision system designed for objective, real-time classification of watermelon ripeness. The proposed prototype combines controlled illumination with RGB imaging and convolutional neural networks trained on thousands of annotated outdoor images collected over multiple growing seasons. A phased development strategy—encompassing proof-of-concept modelling, field integration, and multi-season validation—supports robustness against variable lighting conditions and environmental influences. The anticipated outcome is a reliable, non-destructive decision-support tool for growers, capable of identifying ripe fruit for manual harvesting while providing a technological foundation for future autonomous harvesting and precision agriculture applications.

Abstract: Pipeline transport of hydrogen offers an alternative way to move large volumes of hydrogen from production to use. One method of transport would be to use the infrastructure available for natural gas pipelines, but the specific physical and chemical properties of hydrogen and its degrading effect on metals mean that a different approach to safety considerations is required for practical implementation. Different steel grades show different responses to hydrogen exposure: some microstructures exhibit higher diffusion rates but lower hydrogen solubility, making them more susceptible to degradation. The intensity of this phenomenon depends largely on the microstructure of the steel, its alloy content, and the operating conditions. The aim of this research is to perform a comparative microstructural analysis of the P355NH steel base material and welded joints made using MIG and MIG/TIG welding technologies in pipeline sections with different histories that have been exposed to hydrogen. During the investigation, we used optical microscopic images and hardness maps showing hardness distribution to reveal the characteristics of various material structure details. The study may contribute to optimizing the safety of pipelines used for hydrogen transport and the welding technologies employed, as well as to increasing integrity under hydrogen-loaded operating conditions.

Abstract: Motor vehicles are part of our everyday life, and it is difficult to conceive mobility without them as they represent a form of independence. However, conventional vehicles are being transformed not only from a technological perspective, but also from their propulsion systems. This transformation is driven by the scarcity of fossil fuel reserves, geopolitical concerns, environmental pollution, energy transition challenges, and energy independence goals. The electro-mobility of the future will extend beyond electric vehicles to become an integral part of a diverse green energy mix. Hydrogen, with its zero emissions and high energy content, has gained significant attention in this context. The adoption of such new technology by society requires ensuring safety to prevent accidents that could hinder its evolution. High-priority research directions in the hydrogen economy include safety as a technical, psychological, and sociological issue. The safe and effective operation of hydrogen refuelling stations presents numerous challenges due to hydrogen's physical properties, such as its propensity to leak, flammability, and high-pressure storage requirements. Digital twin technology, which creates virtual replicas of physical systems based on real-time data, has significant potential to address these challenges. This study examines how digital twin technology can be implemented to operate hydrogen facilities more safely and effectively. Hydrogen, as a clean energy carrier, plays a key role in sustainable energy systems, but its handling poses substantial safety challenges. This research provides insights into the potential, benefits, and future outlook for digital twin technology in hydrogen refuelling stations, particularly for enhancing safety and reliability. The findings demonstrate that digital twin technology offers considerable potential for safely developing hydrogen infrastructure and may play a crucial role in transitioning to a sustainable energy system. The study describes the four main components of the technology: physical entity, virtual model, data flow, and analytical system, collectively demonstrating practical applications where 3D visualization enables users to quickly identify hazards. The digital twin system significantly improves safety through real-time leak detection and automatic alerts, increases efficiency by optimizing energy consumption and refuelling processes, and enhances reliability through predictive maintenance. However, widespread adoption of this technology faces challenges including managing large volumes of data, accurately modelling complex processes, and implementing effective solutions. Future development directions include integrating quantum computing, deploying advanced sensor systems, and leveraging artificial intelligence, which together may contribute to developing safer and more sustainable hydrogen infrastructure.

Abstract: Hydrogen plays a key role in global decarbonization efforts, especially in the transition of existing natural gas infrastructure to hydrogen-natural gas (H₂/NG) blends. However, the introduction of hydrogen into existing pipelines presents significant materials science challenges, particularly in the areas of hydrogen embrittlement (HE) mechanisms, degradation thresholds, and pipeline steel compatibility. This article reviews current industrial practices of hydrogen blending, embrittlement mechanisms, the behavior of the main pipeline material groups, and the applied testing and standardization methods, with particular emphasis on impact test, tensile test, slow strain rate test (SSRT), and determination of diffusible hydrogen in welded joints. Standardization of hydrogen testing of austenitic stainless steels shows significant shortcomings, as in contrast to the extensive test descriptions, standards and decades of practical data sets available for carbon steels there is no similarly comprehensive, standardized methodological background available for these materials. The review also highlights the differences between austenitic and carbon steels in terms of hydrogen-related degradation and the applicability of standardized testing methods. This lack makes reliable and comparable classification of hydrogen resistance in austenitic steels difficult. The aim of this study is to provide a summary, research-based guideline for harmonizing material qualification practices related to hydrogen.

Abstract: The local government of Dunaújváros, Hungary, has long recognized the important role environmental protection plays in enhancing the city's competitiveness and attractiveness. Since 1997, the municipality has employed an environmental specialist with a university degree. Environmental status reports, adopted by resolutions of the general assembly, have been published annually since that year. Since 1998, the city has had a municipal environmental protection programme and an environmental financial fund. In 2007, Dunaújváros became the first Hungarian municipality to operate a certified EMAS (Eco-Management and Audit Scheme) environmental management system [6]. The city has been a member of the Covenant of Mayors for Climate and Energy since 2017 [1]. Dunaújváros has participated — and continues to participate — in several European environmental projects and has received numerous national and European Union awards for its achievements in the field of environmental protection. The primary goal of the municipal environmental protection programme is to protect human health, preserve and promote the sustainable use of natural resources and assets. The programme supports the protection and sustainable utilization of individual environmental elements and systems, identifies threats, and aims to resolve and mitigate environmental conflicts in line with the city's characteristics and economic capacities [2]. The newly completed municipal environmental protection programme for the period 2025–2030 is the city's fifth such plan. The requirements concerning the preparation and content of the program are regulated by Act LIII of 1995 on the General Rules of Environmental Protection. The program includes: an assessment of the current situation, based on the condition of environmental elements and analysis of the main influencing factors; environmental protection objectives and target states aligned with sustainable development; the main actions required to achieve these goals (particularly those related to ongoing or planned developments and operations), along with an implementation schedule; regulatory, monitoring, and evaluation tools to support goal achievement; and a breakdown of the expected costs of implementing the measures and tools, including planned funding sources [4].

Abstract: Solar photovoltaic systems are the most dynamically expanding renewable energy technology, their capacities have doubled globally over the last two years. The transition to solar energy offers numerous advantages, it poses significant challenges for the electricity grid stability. These systems have high production fluctuation within the day and vast overproduction in peak hours. To improve stability, economic operation and efficiency of electricity network, both fluctuation balancing and excess energy storage are essential. Presently two technologies are mostly used: battery-based and pumped hydropower energy storage systems. This study focuses on evaluating the operating efficiency of solar-driven pumped hydropower energy storage system in the catchment of Lake Velence under changing weather conditions. Lake Velence has been struggling with severe drought problems for years, posing challenges to water experts, and making fair water distribution difficult for water users. The nearby northern hilly region of the lake provides suitable location for municipal-scale pumped hydropower developments in terms of social, techno-economic and topographical conditions. Furthermore, due to scarce water resources, inefficient operation could cause additional tension among water users, therefore, detailed evaluation of system efficiency is required, along with life-cycle economic analysis and hydrodynamic optimization of reservoirs and pipelines. Using potential reservoir locations identified in a case study from 2025 for pumped hydropower energy storage, together with meteorological data, we analyze and optimize in a self-developed Matlab model 1) the hydrodynamics of the system and 2) evaporation losses of reservoirs, on a daily basis over years, under changing weather conditions. Hydrological evaporation and hydrodynamic friction losses, together with possible interventions to reduce their negative effects, were assessed with life-cycle cost analysis to present environmental-social and economic benefits. Changing weather conditions have significant impact on operational efficiency and can negatively affect water requirements that raise conflicts among water users. The solely solar-driven pumped hydropower systems are spreading but still in their early stages of development. Long-term and extended data on their operation is still limited and their performance under changing weather conditions requires further research. This research investigates hydrodynamic and hydraulic operation efficiency and couples with economic life-cycle cost analysis, supporting guidance for optimization and evaluation of future developments.

Abstract: Buildings represent nearly 40% of global energy consumption; therefore, improving their energy efficiency and thermal comfort has become a key research priority. This study presents the development of a detailed EnergyPlus-based simulation model of a five-building office complex located in Debrecen. The model integrates geometric, building physics and HVAC system characteristics, real operational schedules, weather data, and occupancy profiles. Simulations evaluate electricity and heat consumption as well as thermal comfort indicators such as temperature and PMV. Results show that the model accurately reproduces annual heating and cooling energy demand: simulated heating demand (2190 GJ) closely matches measured data (2108 GJ), while simulated cooling demand (119,283 kWh) aligns with measurements (119,356 kWh). The model provides a reliable foundation for future optimization studies, including data-driven and hybrid predictive control strategies. Future work includes calibration using real measurements and the integration of AI-assisted control.

Abstract: The breakage of agricultural particulate materials occurs throughout harvesting, transportation, post-harvest processing, storage, and milling size reduction operations. Corn particles, as a representative example, exhibit complex mechanical properties due to their different internal structure and moisture-dependent characteristics. This review summarizes recent advances in experimental and numerical investigations of corn particle breakage under various conditions. Breakage experimental measurements provide essential data for numerical simulations based on DEM with breakage models (Ab-T10, PRM, BPM). However, current DEM-based models often rely on simplified homogeneous assumptions that cannot yet reproduce moisture-dependent ductile-brittle transitions observed in real kernels, which limits quantitative prediction accuracy. The integration of experimental observations and simulation results contributes to a useful understanding of energy dissipation, progeny particle size distribution (PSD), and breakage patterns in agricultural materials. At the end, current challenges and potential research directions are discussed regarding agricultural particle fracture to achieve more accurate and scalable predictions of breakage behavior.

Abstract: Increasing the quality of machined surfaces in wire-electrode electrical discharge machining (WEDM) is undoubtedly reflected in the increase in the consumption of electrical energy required to perform the electrical discharge process. The relationship between these two input-output parameters is based on the physical nature of the given process, while the surface quality and the energy intensity of the electrical discharge process are closely linked. At the same time, it is true that with the increasing quality of the machined surface, the electrical energy consumption of individual subsystems and auxiliary devices of the electrical discharge machine also increases in almost all cases. The reason is mainly the fact that the machining time is extended. This is mainly caused by the need for a larger number of passes but also higher demands on the stabilization of the electrical discharge process. Therefore, the aim of the research was to identify and describe the mutual relationships between the quality of the machined surface in WEDM and the total consumption of electrical energy required to perform the machining process.