Periodica Polytechnica (Budapest University of Technology and Economics)
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Changing Competency Expectations in the Labor Market
No full textThe labor market has undergone radical transformations recently, influenced by technological advancements, globalization, and social changes. Although labor market forecasts from 10–15 years ago already anticipated significant transformations, events of the past five years—notably the COVID-19 pandemic and the acceleration of digitalization—have further emphasized the importance of workers' adaptability and skills (IFTF 2011; PwC, 2017; Manpower, 2016; World Economic Forum 2016, 2023, 2025; Cedefop, 2023; OECD, 2024). The development of the labor market competencies is currently shaped by three key factors: technological advancements, economic transformations, and social changes. The labor market transformations presented in this study necessitate adaptation from all labor market stakeholders, including employers, employees, and educational institutions responsible for workforce preparation. As stated in the World Economic Forum report, "Given the rapid pace of change, disruptions to business models almost simultaneously impact employment and the demand for new skills, necessitating urgent and coordinated efforts for adjustment." (WEF, 2025, 8). As a result of technological, economic, and societal transformations, industries are adapting, workplaces are restructuring employment models, and the nature, location, and content of work are evolving. Many occupations are undergoing fundamental transformations, requiring the acquisition of new knowledge and competencies
An Examination of Blended Learning in the Context of Higher Education: Challenges, Adaptive Strategies, and Institutional Support
No full textThis research article utilizes a desktop research technique to thoroughly investigate the blended learning environment in higher education. It specifically focuses on the obstacles, instructional adjustments, and institutional support related to this topic. This study delineates many significant obstacles faced by students by a comprehensive review of existing literature, development of a theoretical framework, and amalgamation of data from previous research. The issues include several aspects, including course design complexities, social-emotional well-being, time management, technology accessibility, and digital literacy. Various theoretical frameworks are used to understand the underlying processes that lead to issues in integrated learning. Employing theme analysis on qualitative insights and theoretical perspectives may provide a thorough understanding of the issues, coping methods, and institutional support systems indicated. Academic institutions are driven to provide practical suggestions based on the identification of significant themes and insights obtained from integrated research results. To foster balanced and inclusive learning environments, we prioritize ongoing assessment of teaching methods, fair and impartial distribution of technology resources, strong support systems, and creative teaching techniques. Academic institutions can foster the academic achievement and personal development of students in the era of digitalization by diligently prioritizing these initiatives that cater to the varied requirements of students. This exhaustive investigation provides policymakers, institutions, and educators with invaluable insights that empower them to effectively manage the intricacies of integrated learning and improve the academic performance of students. 
Upgrading of Waste Tyre Pyrolysis Oil for Obtaining Valuable Products
Full text linkPyrolysis (thermal anaerobic decomposition) of waste tyres is a sustainable recycling process. Its result is an unstable liquid product – pyrolysis oil – must be improved for economic usage. A complex microreactor system was developed for upgrading/valorizing waste tyre pyrolysis oil. Following cleaning steps (distillation, resin removal, chemical preparation reactor) pyrolysis oil was hydrogenated/hydrodesulfurized in the main reactor over NiMo/Al2O3 catalysts. Cheap self-made low active metal containing catalysts presented comparable activities with an industrial (Haldor Topsoe) catalyst in a 100 mL flow reactor at 300 °C temperature and 25–35 bar pressure. The process was optimized by changing the pressure, the liquid hourly space velocity (LHSV) and the hydrogen flow rate. The upgrading of the process for a 1000 mL volume flow system is in progress
Rheological Behavior and Improved Swelling of Porous Semi-IPN Hydrogels Based on Poly(isopropylacrylamide-co-itaconic Acid)/Sodium Alginate – In Vitro Theophylline Release Analysis
Full text linkA series of semi-interpenetrating networks (semi-IPN) hydrogels composed of temperature sensitive poly(N-isopropylacrylamide) (PNIPAAm) and pH sensitive itaconic acid (IA) and sodium alginate (SA) were prepared by radical copolymerization/crosslinking reaction. The structures, morphology, thermal, rheological and swelling behaviors of the hydrogels were studied. The evidence for successful synthesis was confirmed by infrared spectroscopy. In thermal analysis, all prepared semi-IPN samples showed a clear endotherm corresponding to a volume phase transition temperature. Morphological aspects of the samples displayed highly porous structure and expanded network depending on alginate content. Rheological analysis showed that all measured viscoelastic properties were influenced by gel composition and temperature; a sharp transition to higher values of the storage modulus G' was observed above the transition temperature. The swelling behavior revealed the high sensitivity of samples for temperature and pH: higher swelling was observed in simulated intestinal fluid (SIF) than in gastric one (SGF). Moreover, the swelling drops radically as the temperature rises up to 37 °C. In both fluids at 20 °C and 37 °C, the swelling is diffusion-controlled mechanism with a Fickian transport. From in vitro degradation study, the hydrogels were degradable in pancreatin-containing SIF solution at 37 °C and samples with higher alginate ratio showed high degradation rate. The high cumulative release of theophylline observed in SIF provides a significant improvement for drug delivery from these hydrogels to intestinal regions; the release profile displays close fitting to Korsmeyer-Peppas model with Fickian transport
Plate Buckling Assessment of Unstiffened and Uniaxial Compressed Plates through Overall Imperfection Method
Full text linkThe Overall Imperfection Method (OIM) is a more comprehensive version of the Unique Global and Local Imperfection Method introduced for steel column design in EN 1993-1-1 standard. The generalized OIM is used to evaluate the stability resistance of steel members subjected to irregular load conditions. This study extensively examines the Overall Imperfection Method (OIM) used in analyzing plate buckling, explicitly focusing on steel grades such as S235, S355 and S460. It compares OIM with methods mentioned in EN 1993-1-5 (Annex B, GMNIA and winter curve). The research carefully validates OIM by analyzing Equation (13) (Annex B) across ratios and studying its behavior with various steel grades. The study highlights the importance of finding a balance when applying OIM regarding material properties and slenderness ratios. These findings provide insights for engineering professionals. Additionally, the research introduces a calibrated equation that allows for the application of OIM without exceeding the limits set by GMNIA. This simplifies its implementation in engineering practice
Developing Hybrid Algorithms with Fire Hawk Optimization on Concrete's Chloride Diffusion
Full text linkThroughout their lifespan, reinforced concrete buildings may encounter many challenging circumstances, such as exposure to chloride ions. Exposure to the elements, particularly in coastal areas, may lead to a decrease in durability and degradation of concrete structures. Artificial intelligence (AI) may be utilized to create models that accurately predict the chloride diffusion coefficient (CD) of non-steady state concrete over a long duration by analyzing experimental field data. This approach has the potential to boost the evaluation of the durability of a certain building structure by highlighting the most significant factors. This work showcases the use of the support vector regression (SVR), multi-layered perceptron (MLP), and random forests (RF) for predicting the DC of concrete under different exposure conditions. The fire hawk optimization algorithm (FHOA) approach was employed to improve prediction models that were trained on a dataset consisting of 216 data points. The findings indicate that the RFFHOA, MLPFHOA and SVRFHOA models have significant promise in properly forecasting the CD of concrete under different exposure situations while maintaining acceptable R2 values. The results suggest that RFFHOA, MLPFHOA and SVRFHOA may reliably predict specific CD values in various exposure situations. The RFFHOA attained R2 values of 0.9951 throughout training and 0.9971 throughout testing. In detail, MLPFHOA had a R2 value of 0.9659 throughout training and 0.9756 throughout testing. The R2 value for SVRFHOA's test stage is 0.9835, whereas the training stage is 0.9659
Stress Intensity Factor in Top-loaded Thin Hemispherical Domes: A Combined Experimental and Numerical Study
Full text linkMeasuring the stress intensity factors (SIF) at the tip of the meridian cracks of a dome can help evaluate the fracture process. The calculation of the SIF for planar cracks, based on truncating the Williams' series expansion, can be extended to curved surface cracks using the equivalent plane transformation method. This study investigates the effects of dimensions, crack length, and distributed loading area on the SIF at the crack tip, both experimentally and numerically. The results show that dimensionless SIFs generally increase with the crack length, distributed loading area and thickness ratio (thickness/ radius). The distribution load prevents any tension within the contact zone and suppresses top-surface radial cracking. The effect becomes more pronounced as the model thickness increases. Within the bearing capacity limits, designing a wide loading edge can effectively inhibit the propagation of meridian cracks and increase the service life of the dome
Study on Construction Optimization Method of Tunnel Crossing Fault Fracture Zone
Full text linkWhen a highway tunnel intersects a fault fracture zone, the excavation process disrupts the surrounding weak and fragmented rock mass, compromising the stability of the fault zone. This study compares the deformation and stress distribution of the surrounding rock using the reserved core soil method, central diaphragm (CD) method, and cross diaphragm (CRD) method during tunnel excavation through fault fracture zones. Among these, the CRD method is identified as the safest construction technique. Additionally, to address the significant deformation of the surrounding rock when tunneling through fault zones, the impact of various pre-support and advance reinforcement techniques on rock mass deformation is analyzed. By comparing the full-ring grouting method with the optimized reinforcement zone approach, the findings demonstrate that optimized grouting significantly reduces disturbance to the fault fracture zone during excavation, thereby enhancing the overall stability of the surrounding rock mass
Investigation of the Effect of Nanoparticles in Phase Change Materials on Heat Transfer in Building Wall
Full text linkPhase change materials (PCMs) offer a viable approach for improving energy storage and thermal regulation in the construction industry. Despite their integration ease with building materials, PCMs face challenges with thermal conductivity. This study explores the effectiveness of different PCMs in reducing building energy consumption and investigates the role of nanoparticles in enhancing PCM conductivity. Specifically, the research evaluates three PCMs— N-octadecane, N-eicosane, and N-hexadecane—and examines the impact of two additives, Al2O3 and CuO, on thermal performance. Detailed analysis of temperature and heat flow parameters demonstrates that nanoparticle additives significantly enhance thermal conductivity and improve PCM absorption. Notably, higher nanoparticle concentrations result in delayed peak amplitudes by up to 1.5 hours and influence viscosity. Among the PCMs tested, N-hexadecane emerges as the most effective for improving winter thermal comfort in buildings, while N-octadecane is preferable for its melting point characteristics