Periodica Polytechnica (Budapest University of Technology and Economics)
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Insights into Pipe Jacking-induced Ground Deformation Considering Dynamic Cutter Excavation Effect through Numerical Modelling
Full text linkThe pipe jacking method has been increasingly applied to a variety of tunnel projects. Investigating the ground disturbance characteristics during pipe jacking is of great significance to ensure accurate safety assessment and timely ground deformation control. This paper developed a three-dimensional model to simulate the entire pipe jacking process of a shallow-buried cross passage tunnel in soft strata. A key contribution of this research is the development of an element shear failure approach, combining element failure method with shear failure modeling. Meanwhile, the dynamic cutter excavation effect and the soil shear failure were considered in the numerical modeling. Through the comparison with the field monitoring results and traditional numerical simulation approach, the effectiveness, reliability, and superiority of the proposed approach were well demonstrated. Moreover, based on the numerical results, the ground deformation characteristics along with the stress-strain state of the cutter head during the soil excavating process were thoroughly analyzed. The proposed approach and its application in the ground disturbance analysis will offer useful references and guidance for numerical studies in similar pipe jacking projects in near future
Modeling and Performance Analysis of 3D Structured Rectilinear Rogowski Coil Using Finite Element Method
Full text linkThis paper proposed a discrete Rogowski coil (RC) model, consist of rectilinear solenoids (S) connected in series. This model is designed using ANSYS Maxwell software for different shape of primary conductor and the mutual inductance (M) between RC model are calculated. The paper discussed about impact of various shape and different position of primary conductor. The M between the RC model and straight circular, rectangular cross section and D-shaped conductors are evaluated using the Finite Element Method (FEM). The effect of cross section of primary conductor on M has analyzed and reported. For larger numbers of S, eccentricity of conductor will decrease so that output of coil is also improved. In this study, the distribution of magnetic field is examined for changes in the position of the conductors. The designed RC model output is studied with respect to the power and high frequency input signals. A discrete RC is tested using simulated standard sinusoidal and impulse (8/20 μs) as an input signal. Performance of the RC is analyzed, and its results for the different input magnitude is reported. An output characteristic and sensitivity of the designed RC have also been determined and reported
Numerical Simulation of the Thermal Behavior of a Lithium-ion Cell Pack with Various Thermal Dissipation Structure and the Addition of Phase Change Materials
Full text linkThis study presents a transformative approach to passive thermal management in lithium iron phosphate (LiFePO4) battery packs through geometrically optimized aluminum cooling structures. We investigate four distinct configurations - baseline (uncooled), unilateral side plate, inter-cell plates, and molded enclosure using experimentally validated COMSOL Multiphysics simulations under extreme 20C discharge conditions (50 A per cell). The most advanced design, featuring an aluminum mold surrounding 90% of each cell's height, achieves an unprecedented 11 °C reduction in peak temperature (from 66 °C to 55 °C) compared to conventional uncooled packs, while maintaining 99.1% of original power output (1107 W vs. 1118 W). This performance surpasses existing passive cooling methods and rivals many active systems, accomplished through three key innovations: 1. a patented snap-fit aluminum geometry that enhances heat transfer while simplifying assembly, 2. strategic material distribution that reduces thermal gradients by 32% compared to baseline, and 3. a cost-effective solution adding less than $1 per pack in material expenses. Furthermore, when combined with paraffin phase change material, the system demonstrates additional thermal buffering capacity, delaying critical temperature thresholds by 4.2 minutes during overload conditions. These findings provide battery designers with validated, scalable solutions that address the critical trade-offs between cooling performance, power output, and manufacturing complexity in next-generation energy storage systems
Integration of Thermal Energy Storage and Photovoltaic Systems by Using Domestic Electric Water Heaters: A Case Study of Austria and Hungary
Full text linkLately, the prices of photovoltaic (PV) technology, including modules and inverters, have significantly dropped, making it more economically feasible to use PV power for heating water in homes. Although thermal energy storage (TES) has the potential to balance energy supply and demand, it remains largely underexplored. TES solutions may have a key role in dealing with the adverse effects of the dynamically growing share of electricity generated by photovoltaic (PV) systems on electricity networks. This research explored the potential of implementing a novel technological approach in conjunction with PV usage in Austria and Hungary, aiming to encourage the adoption of economical energy storage solutions and lessen energy dependence. This study aimed to investigate the joint use of TES and PV systems in Austria and Hungary, specifically using a 3.5 kW quasi-sine inverter and an electric water heating appliance for households with a capacity of 200 liters, as examples. According to the results of the research, the tested 200-liter domestic electric water heating system can store an average of more than 16 kWh of heat energy per day during the summer months, with a maximum water temperature increase (ΔT) of up to 53 °C during this period. The research is innovative and practical, as it explores the application of this solution to assess the seasonal energy-saving potential of this method of sensible heat storage in the contexts of Austria and Hungary
Performance Improvement of A356 Cast Aluminum Alloy by Adding TiO2 Powder and Stirring in Microstructure and Strength
Full text linkThis study aims to improve the performance of A356 cast aluminum alloy by incorporating titanium dioxide (TiO2) powder and applying variations in stirring speed during processing. The effects of these modifications were evaluated based on microstructural characteristics, tensile strength, and impact strength. The methodology includes a casting process with TiO2 concentrations of 0%, 5%, 10%, and 15% by weight, along with variations in stirring speed (300, 400, 500 and 600 RPM) to ensure homogeneous powder distribution within the aluminum matrix. The mechanical properties of the A356 + TiO2 composite, including tensile strength, elastic modulus, strain, and impact energy, were evaluated. Furthermore, the material's microstructure was examined using optical microscopy. The results indicate that the addition of TiO2 contributes to an increased titanium content in the alloy, leading to microstructural changes characterized by the formation of finer dendrites. Furthermore, the combination of TiO2 addition and increased stirring speed significantly enhances the material's tensile and impact strength. With the addition of TiO2 by 15%, there is an increase in tensile strength of 14.2% and impact strength of 21%. Likewise, with an increase in rotation up to 600 RPM, tensile strength increases by 14.9% and impact strength increases by 8.2%. These findings provide valuable insights into the development of advanced aluminum-based materials for industrial applications, particularly in the automotive and aerospace sectors
Sensitivity Parameters of Transport Networks and Vulnerability Assessment of Critical Network Elements: Literature Review
Full text linkNetwork sensitivity has recently become an important topic, with an increasing number of articles appearing on the subject. Identification of critical sections within transport networks is also essential for transport modelling. A well-developed methodology can help to improve the network to minimize the impact on road users in the event of future emergency cases (accidents or attacks). For this purpose, existing articles were assessed to determine what progress has been made in network sensitivity and what parameters and approaches have been used so far. After reviewing the articles, it became clear that a significant number of methods have been used to identify critical sections, and it became visible which areas are worth further work. Among the methodologies used, simplified networks have been the main focus, but there is a need for a more detailed analysis based on industry demand and available data
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– Ormándy Marcell Ottó: CRediT – a közreműködői szerepek taxonómiája az ALA ajánlásával
– Ormándy Marcell Ottó: Mobiltechnológia bevezetése elsőgenerációs indiai könyvtárakban
– Bubnó Katalin: Befogadó gyűjtésszervezés, befogadó katalogizálás: Díjnyertes, a sokszínűséget tükröző könyvek beszerzése és leírása
Interjú Zichy Mihály tudományos kutatóval, aki 2025 márciusában Magyar Arany Érdemkereszt polgári tagozat kitüntetésben részesült
No full textZichy Mihály, a Magyar Nemzeti Múzeum Közgyűjteményi Központ OrszágosSzéchényi Könyvtára Kézirattárának nyugalmazott tudományos kutatójaMagyar Arany Érdemkereszt polgári tagozat kitüntetésben részesült
