Periodica Polytechnica (Budapest University of Technology and Economics)
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Synthesis of Chitosan-ortho-vanillin/AgNPs Schiff Base Composite as Food Preservative
Get PDFStructural modification of chitosan (CH) may enhance the stability of silver nanoparticles (AgNPs) synthesized. This study aims to modify chitosan into chitosan-ortho-vanillin Schiff base (CHoVSB), which was used as a capping agent in the synthesis of AgNPs, and were evaluated as the food preservative through the antimicrobial testing. Composites of AgNPs were synthesized using AgNO3 as an Ag precursor, ascorbic acid as a bioreductor, sodium tripolyphosphate (STTP) as a crosslinker and chitosan or CHoVSB. They were characterized by ultraviolet-visible (UV-Vis), Fourier transform infrared spectroscopy (FTIR), atomic absorption (AA) and scanning electron microscope-energy dispersive X-ray (SEM-EDX) analyses. CHoVSB was synthesized as a brownish-yellow solid with a yield of 57.6% and a degree of substitution of 44.09%. The composites of CH/AgNP were brownish-yellow solids with yields of 80.8–83.4% (w/w), and exhibited surface plasmon resonance (SPR) peaks at 420–439 nm. CHoVSB/AgNP-1 and CHoVSB/AgNP-2 composites produced were green solids with yields of 72.5 and 80.3% (w/w), and SPR peaks at 419 and 447 nm, respectively. CHoVSB/AgNP-2 composite was found the best product featuring spherical shape with a size of 21 nm and a uniform particle distribution. It has displayed the potential to be used as a food preservative with the highest percentage of bacterial reduction of 99.5 and 98.6% at a concentration of 1000 ppm for 3 and 7 days of observation, respectively
Neural Network Modeling and Sensitivity Analysis of Factors Influencing Dynamic Compaction Vibration Velocity
Get PDFDynamic compaction vibrations (DCV) cause significant environmental impacts. Quantifying key influencing factors is essential for mitigation. This study examines how tamper radius, tamping energy, tamping times, and tamping settlement affect DCV velocity (4000-25000 kN·m energy range) in a miscellaneous fill site. A BP neural network model was developed with these four parameters as inputs and vibration velocity as output, and the influence of each factor on vibration velocity was evaluated in combination with Sobol sensitivity analysis. The results show that Vibration velocity and tamper radius follow a negative exponential power function relationship. 97% of total vibration attenuation occurs within a 60 m radius. Vibration velocity growth rate decelerates with increasing tamping energy. 98% of velocities are below 30 mm/s, demonstrating strong data clustering. With the increase of tamping times or tamping settlement, the vibration velocity first rises to the "peak point", and the peak point corresponds to 4-6 tamping times and tamping settlement at 0.68-0.82 m and 3.08-4.30 m, and then declines or stabilizes. The tamper radius is the main factor affecting the vibration velocity. Optimizing or controlling the tamper radius can significantly reduce the vibration of DCV. The influence of tamping settlement is second, and the tamping energy and tamping times have a smaller impact
Experimental Measurement and Energy Evaluation of the Geothermal Water Energy Utilization in a Thermal Swimming Pool
Get PDFThis work focuses on the experimental measurement of the temperature and flow of cold, geothermal, pool and waste pool water of a thermal swimming pool in southern Slovakia. The measured quantities are necessary for the energy evaluation of geothermal water energy utilization. It is clear from experience that the geothermal energy utilization rate often does not even reach 40%. The remaining energy is considered waste, and in the form of waste pool water with too high temperature, it is most often discharged into surface streams. The results of the study showed that by applying appropriate measures to recover heat from waste pool water, it is possible to increase the energy utilization rate of thermal water from 40% to 85%, which is the ideal energy utilization rate according to energy point of view. At the end of the article, methods will be presented, thanks to which it would be possible to reduce the temperature of waste pool water to the value required by law and at the same time increase the rate of thermal water energy use
Possibilities for Further Development of the Airbags in the Case of Non-conventional Seating Positions
Get PDFThe first ideas and experiments aimed at protecting passengers from the vehicle’s internal components with airbags date back to the 1960s. Twenty years later, the airbag appeared in series production, in December 1980, the Mercedes-Benz S-Class (W126) was the first serial production car to be equipped with a driver airbag, and since its introduction, the use of airbag technology has been uninterrupted. Airbag systems are currently regarded as almost mandatory protection systems in a vehicle. The article generally presents the development of airbags used in cars, followed by the currently used airbag folding types. After that, the article presents the simulation of the airbag deployment, its types and theoretical background, as well as the most important stages of the deployment of the airbag. In the following, the article presents the results of the research so far in the case of frontal and side crashes. The next section of the article introduces the materials capable of absorbing energy, then details the simulation model built and the airbag concept created. The last part of the article contains an evaluation of the results and the summary. The modified seat examined in the earlier phase of the research and the airbag concept that is the subject of this research also fulfill the set goals, but the latter has a great advantage
Digitális transzformáció közgyűjteményekben konferencia a Széchenyi István Egyetemen
No full textOn the occasion of the 50th anniversary conference of the University Library and Archives of Széchenyi István University, Győr, held on 10 October 2024, we offered a training course for library and archives professionals. The training focused on the benefits of digital technology for public collections. Digital transformation is essential for the modernisation of institutions. The panel sessions covered topics including digitization in collections, library automation, development of integrated library systems and the AI-assisted proofreading of scientific publications.A győri Széchenyi István Egyetem Egyetemi Könyvtár és Levéltára 2024. október 10-én rendezett 50 éves jubileumi konferenciája alkalmából továbbképzést szerveztünk könyvtári és levéltári szakemberek számára, bemutatva a digitális technológia közgyűjteményeknek nyújtotta lehetőségeit. A digitális transzformáció szükségszerű az intézmények működésének megújításához. A szekcióülések fókuszába a közgyűjteményi digitalizálás, valamint a könyvtárak számítógépesítése, az integrált rendszerek fejlődése és a tudományos közlemények gépi lektorálása került
The Fundamental Geotechnical Characteristics of Recycled Concrete Aggregates of Various Fractions
Get PDFThe purpose of this study is to determine the fundamental characteristics of a recycled concrete aggregate for its utilization in geotechnical constructions. Minimum and maximum bulk densities, the shear strength properties, and the deformation properties were tested in the laboratory. The tests were performed on recycled concrete aggregates of basic fraction, i.e., 0-16 mm, and separated fractions, i.e., 0-4 mm, 4-8 mm, and 8-16 mm. The laboratory tests on the recycled concrete aggregate were compared with the results of the natural aggregates sorted into comparing fractions with the recycled concrete aggregate. The bulk density of the recycled concrete aggregate was either less or equal to that of the natural aggregate. The shear strength properties of the recycled concrete aggregates were greater than the shear strength properties of the natural aggregates except for the fraction of 8-16 mm, where it was the opposite. The one-dimensional compression modulus of the recycled concrete aggregate is slightly lower than that of natural aggregate for the fractions of 4-8 mm, 8-16 mm, and 0-16 mm. However, for the fraction of 0-4 mm, which is not typically used in the creation of recycled concrete (because it is replaced by the natural aggregate), the recycled concrete aggregate has a higher shear strength and compression modulus than natural aggregate
Predicting Engine Parameters with Cost Efficient AI Models – An Experimental Method Validation
Get PDFArtificial intelligence (AI) methods have rapidly become a best practice in various industrial applications due to their exceptional predictive abilities. Compared to traditional physical and chemical models, AI-driven approaches typically offer faster computation times without sacrificing accuracy. This makes them well-suited for enhancing or replacing conventional methods in engine technology. Building on this potential, our previous work focused on developing AI-based tools to accelerate the development of novel e-fuels for internal combustion engines. These AI tools require representative training datasets created through expensive engine dyno measurements. To address this challenge, we developed a general methodology to improve the cost-efficiency of dataset creation. This paper presents the experimental validation of this methodology by assessing its performance on seven different predictive tasks. Following the proposed framework, we designed and conducted an engine dyno experiment, then developed AI models to predict seven critical engine performance and emissions parameters: center of heat release, ignition delay, peak combustion temperature, peak pressure rise rate, brake thermal efficiency, exhaust opacity and NOx emissions. The results demonstrated the effectiveness of the methodology, with five out of seven models achieving excellent predictive performance on unseen test data (R2 > 0.97). Peak pressure rise rate and opacity models had slightly lower performance (R2 > 0.94), however, given the well-known challenges associated with predicting these parameters, the results are acceptable
Performance of PMMA and SBS Modified Asphalt Mixtures in Railway Supplementary Layers and Road Pavements
Get PDFThe use of recycled waste elastic materials provides a cost-effective and environmentally friendly option for further modifying the performance of asphalt mixtures. Therefore, the effects of different proportions of (PMMA) polymethyl methacrylate derived from waste plastic material were evaluated using the Indirect Tensile Strength Test (ITST) of lab-prepared specimens. Since numerous methods of modifying the conventional asphalt binder are available, in this research, the virgin binder was modified with 1%, 2%, 3%, 4% and 5% PMMA for evaluating optimum performance proportions in terms of Marshall stability and ITST of asphalt mixtures. Furthermore, stiffness modulus tests were performed at frequency values of 1.2 Hz, 1.9 Hz, 3.9 Hz and 5 Hz. The effect of the loading rate from 10 MPa/s to 70 MPa/s was evaluated with an increment of 10 MPa/s for all proportions. Moreover, finite element modeling was performed using the data obtained from dynamic modulus tests with modified Burger's Logit model for evaluation of rutting progression. Results show improved performance of asphalt mixtures with the addition of PMMA, leading to variation in properties including penetration, softening point, Marshall stability and rutting resistance. It is recommended to use 5% PMMA for increased indirect tensile strength, Marshall stability, rutting and fatigue damage resistance
