Periodica Polytechnica (Budapest University of Technology and Economics)
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Stackability planning in informal learning and soft skill acknowledgments
No full textThis paper assesses the issue of stackable learning paths in the context of expanding the capabilities of the DCP host that manages digital badges based on the Open Badge 2.0 standard. Blockchain technology helps to keep diverse, interrelated data elements in a coherent unit. The up-to-date state of the stackable certificate system supported by soft skills is ensured by IPFS-based data storage. A model for this is presented in the paper
Recenzió Holczinger Norbert és Sárvári Balázs „Fenntartható közgazdaságtan” című oktatói kézikönyvéről
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Comparison of α-Fe2O3 Nanocatalyst Synthesized with Various Surfactants and its Application in Phenol Degradation
Full text linkBreaking down organic pollutants like phenol is possible with the use of a sophisticated oxidation process called photo-Fenton. The α-Fe2O3 catalyst was chosen because it has a small bandgap value so it is effective in degrading organic compounds through a clean photocatalytic reaction mechanism. This study aims to synthesize α-Fe2O3 nanocatalysts to be applied in the phenol degradation process through the photo-Fenton reaction mechanism. The catalysts were made using a variety of surfactants in surfactant-assisted coprecipitation. In a batch setup, phenol degradations were performed with an initial concentration of 50 mg/L and reaction times of 120 min where the optimum pH value was searched initially. The concentration of phenol was analysed using a UV-Vis spectrophotometer. The characterization results showed that particle agglomeration of α-Fe2O3 catalysts was reduced by adding surfactant resulting in moreordered nanoparticles. The XRD pattern also showed that the α-Fe2O3 nanocatalyst with hexagonal structure was successfully formed where the average crystal size based on the Scherrer equation was 38 nm. The BET test results showed that the α-Fe2O3-SDS nanocatalyst had the largest surface area of 17 m2/g compared to the α-Fe2O3-CTAB and α-Fe2O3-PEG nanocatalysts. The results of the catalyst activity test showed that the α-Fe2O3 nanocatalyst could degrade phenol compounds with the largest degradation percentage of 47% obtained with the photo-Fenton process using a catalyst synthesized with SDS surfactant. The results of this study also prove that the photo-Fenton process can degrade phenol better than the Fenton process using the α-Fe2O3 nanocatalyst
Investigation of the Structural, Thermal, Spectroscopic, and Electronic Properties of Praseodymium-based Hydroxyapatites Co-doped with Silver and Zinc in Varying Concentrations
Full text linkThis study investigates the crystal structure, energy gap, band structure, spectroscopy, thermal, and electrical properties of Pr3+-based hydroxyapatites (HAp) co-doped with Zn2+ and Ag+ in varying concentrations. The synthesized samples, designated as 0.25Zn-0.25Pr-HAp, 0.50Zn-0.25Pr-HAp, 0.75Zn-0.25Pr-HAp, 0.25Ag-0.25Pr-HAp, 0.50Ag-0.25Pr-HAp, and 0.75Ag-0.25Pr-HAp, were prepared using a wet chemical method. The materials were characterized by Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), differential thermal analysis (DTA), and thermogravimetric analysis (TGA). Additionally, theoretical calculations employing density functional theory (DFT) were conducted to analyze the band structure (BS), energy gap (Eg; EHOMO-ELUMO), and density of states (DOS). Results revealed a progressive reduction in the bandgap with increasing dopant concentrations, particularly in Ag-doped samples. Notably, 0.75Ag-0.25Pr-HAp exhibited the smallest bandgap of 3.983 eV, indicating enhanced electronic conductivity and potential applications in bioelectronics and medical sensors. Furthermore, the co-doped samples demonstrated reduced crystallinity, larger crystallite sizes, and excellent stability in biological environments, alongside superior biocompatibility and antibacterial properties. Among the synthesized materials, 0.75Ag-0.25Pr-HAp exhibited promising characteristics as a biomedical material for bone-related applications, owing to its structural stability, enhanced electrical properties, and suitability in antibacterial and bioelectronic devices. This investigation highlights the versatility of Zn/Ag co-doped Pr-HAp materials for advanced biomedical and technological applications
Determination of Rail Dilatation Movements at Tunnel Gates for Ballasted Railway Tracks
Full text linkWhere railway tracks pass through tunnels, the temperature conditions on the railway superstructure are different from those on the connecting track sections. Due to the temperature difference at the tunnel, dilatation movements occur even in cases of construction of continuously welded rail (CWR) tracks. The aim of this research is to determine the magnitude of the movements resulting from heat expansion and the normal force in the rail in the region of the tunnel gates, both in the tunnel and in the sections of track on the connecting earthworks. Ballasted and straight tracks with rail section of 54E1 are assumed in this paper