Periodica Polytechnica (Budapest University of Technology and Economics)
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Modeling Fuel Consumption of Heavy-duty Trucks Using Telematics Data
Get PDFFuel is the largest cost component in Vehicle Operating Costs (VOC) and a significant contributor to greenhouse gas (GHG) emissions in the trucking sector. This study developed a real-time telematics-based fuel consumption model for Euro-3 and Euro-4 trucks operating on toll roads in Indonesia, focusing on 5-axle heavy-duty trucks. The model utilizes telematics data, including average speed, gross vehicle weight, and road gradient under free-flow conditions, a novel aspect of this research. Two modeling approaches were applied: Model 1 employed multiple linear regression with Box-Cox transformation, while Model 2 utilized Generalized Linear Models (GLM) with a Gamma distribution and log link. Model 1 performed better, explaining 85.8% of the variability in fuel consumption (adjusted R2 = 0.858) with a deviance of 0.947, RMSE of 0.033, and AIC of −3.246.625. Conversely, Model 2 recorded a deviance of 8.827, RMSE of 0.296, and AIC of −2.483. The Wilcoxon Signed Ranks Test indicated no significant differences between predicted and observed fuel consumption for both truck types, with a Z value of −1.700 (p = 0.089) for Euro-4 and −0.038 (p = 0.970) for Euro-3, supporting the model′s reliability. Beyond optimizing fuel consumption, the model offers practical recommendations for truck operators considering conversion to Euro-4 and provides valuable insights for policymakers developing energy efficiency strategies in the transportation sector. Further research is recommended to expand the model′s application to non-toll routes and integrate machine learning for more complex patterns
Punching Shear Performance of High-compressive Flat Slabs Reinforced with Hybrid Fibres
Get PDFA framework is presented to explore the influential role of hybrid fibers on the performance of two-way flat slabs against punching shear failure. A finite element (FE) modeling approach via the ATENA-GID software package is used to simulate the case study. Four variables are covered in this investigation including different mix proportions of hybrid fiber-reinforced concrete (HFRC), which contains 0.2% of macro synthetic fibers, and (0.68, 0.8, and 0.96%) steel fibers (SFs) (volumetric ratios), high compressive strengths of 50, 70, and 90 MPa, different main steel reinforcement ratios based on main steel bars of 16, 20, and 25 mm, as well as 150, 200, and 250 mm as thicknesses of the slab. 106 two-way slabs (1900 × 1900 mm) models were generated in this investigation, besides 8 verification materials models. Furthermore, a parametric analysis was performed on the results of FE modeling. The FE modeling results of verification materials tend to be accurate with a correlation coefficient (R2 = 0.9578). Moreover, the outcomes of the study show; that the hybrid fibers' effective ratio comprises about 0.96% SFs and 0.2% macrosynthetic fibers, using 0.54% of main steel reinforcement ratio which is supposedly more economical than other ratios of main reinforcement, 150 mm is a crucial thickness of the flat slab with 70 or 90 MPa as high compressive strength. The combined results can enhance the performance of the flat slab by preventing shear punching failure
Az irodalom lelki egészségvédő szerepe társadalmunkban
No full textThe purpose of this study is to describe the Reading project organized by the Association of Hungarian Librarians in Slovakia from 2021, and the significance of the bibliotherapy method applied within the project. As part of the continuation of the project from 2024, the participants also became acquainted with a new method, called fairy tale therapy. The concept and practical benefits of fairy tale therapy are described, with a separate detailing of the practice of the „Kincskereső” fairy tale therapy method.A beszámoló célja ismertetni a Szlovákiai Magyar Könyvtárosok Egyesülete által 2021-ben indított Olvasás projektet, illetve a programon belül alkalmazott biblioterápiás módszer jelentőségét. A résztvevők 2024-től a projekt folytatásának keretében egy újfajta módszerrel, a meseterápiával is megismerkedtek. Dolgozatomban bemutatom a meseterápia fogalmát, gyakorlati hasznát, külön részletezve a Kincskereső Meseterápiás Módszer gyakorlatát
Phytochemical Profile of Zygophyllum paulayanum Extracts and their Promising Biological Activities
Get PDFZygophyllum paulayanum (syn. Fagonia schweinfurthii), a desert species known for its remarkable adaptation to harsh environmental conditions, has long been recognized for its medicinal properties, including antioxidant, wound healing, anti-inflammatory, antibacterial, anticancer, and antipyretic effects. This study aims to optimize the extraction process of its bioactive compounds using a range of solvents from non-polar to polar at different temperatures, followed by phytochemical screening. The hot ethanol extract was selected for further fractionation into non-polar to polar fractions, which were subsequently analyzed for phytochemical content and biological activities. The n-hexane fraction was found to be rich in fatty acids (24.71%), such as linoleic, palmitic, oleic, linolenic, stearic, lauric, and myristic acids, while the ethyl acetate fraction was abundant in polyphenols (22.14%). Notably, the ethyl acetate fraction exhibited the highest antibacterial activity, inhibiting strains of Pseudomonas aeruginosa (NCIM 5029, PAW1) and Staphylococcus aureus (NCIM 5021, S8). In addition to its antibacterial effects, both the n-hexane and ethyl acetate fractions showed positive responses in phytoestrogenic assays. Meanwhile, the ethanol fraction, rich in flavonoids (5.82%), tannins (4.95%), and alkaloids (18.50%), demonstrated the strongest antioxidant activity (92.08%) at concentration 100 µg/mL, water fraction rich in saponins (16.10%), exhibited the most potent anti-inflammatory effect (59.78%) at concentration 1000 µg/mL. The LC/QTOF-MS (liquid chromatography-quadrupole time-of-flight mass spectrometry) data of hot ethanol extract showed presence of phenol, flavonoids, saponins, alkaloids, and phytosterols cyclitol in plant. These findings highlight Zygophyllum paulayanum as a valuable source of bioactive compounds with promising therapeutic potential across various biological activities
Synthesis and Characterization of SnO2/S,N-Carbon Quantum Dots as Photoelectrochemical Water Splitting Material
Get PDFGiven the growing global demand for renewable energy and the need for sustainable hydrogen production, the development of efficient photoelectrochemical systems for water splitting has become a critical area of research in addressing the energy crisis and reducing greenhouse gas emissions. This study investigates the synthesis of SnO2 thin film photoanodes using ultrasonic spray pyrolysis (USP) and hydrothermal methods, with the aim of evaluating the effects of S,N-carbon quantum dot (CQD) modification on photoelectrochemical performance. The S,N-CQDs solution was varied in volume (2.5, 5, 7.5, and 10 mL) and applied to the SnO2 thin films. The resulting SnO2 microstructure exhibited a spherical morphology with distinct atomic concentrations of Sn and O. Photoelectrochemical characterization, performed via linear sweep voltammetry (LSV) and cyclic voltammetry (CV), demonstrated that the SnO2 thin film modified with 7.5 mL of S,N-CQDs solution produced the highest photocurrent density of 0.0356 mA/cm2, along with an optimal photoconversion efficiency (PCE) of 0.0084%. Furthermore, the SnO2/S,N-CQDs photoanode with 7.5 mL of S,N-CQDs exhibited a double-layer capacitance (Cdl) of 0.1175 mF/cm2, indicating enhanced electrochemical active sites. These findings suggest that the incorporation of S,N-CQDs into SnO2 thin films effectively increases the active surface area, thereby improving the efficiency of the photoelectrochemical water splitting process
Volume of Fluid Implementation of Water Inrush and Escape Route Optimization in Tunnel
Get PDFWater inrush is the most common tunnel engineering disaster, which seriously threatens the life safety of construction personnel. Effective escape route planning is an important measure to reduce casualties. The effects of water inrush velocity, water inlet diameter, water inrush inlet position and water outlet condition on the tunnel water inrush are analyzed by numerical simulation based on VOF (volume of fluid). The results reveal that the tunnel with the water inrush side is the dominant channel of water inflow, and its water level and flow velocity are greater than that of the cross passage, which is the priority escape channel. After water flows to the tunnel port and rushes back, the water level in the tunnel increases rapidly, forming an obvious flow velocity and water level sudden change front. Increasing the water inrush velocity or the water inlet diameter, the increase of the water flowrate makes the water level and flow velocity in the tunnel larger. Water inflow from baseplate is more likely to form high water level and high flow velocity. Escape route recommendations: From the inside wall of the tunnel with water inrush side, through the inside wall of the cross passage to the tunnel without water inrush side to take refuge, and finally through the inside wall of the tunnel to escape from the tunnel with water inrush disaster. This study has certain guiding significance for the escape route design of tunnel water inrush engineering disasters
An Improved BS_NAHOSM Hybrid Control Strategy for FOC of Dual Star Induction Motor Drives
Get PDFIn this paper, a novel adaptive hybrid control structure for field-oriented control (FOC) of six-phase induction motor (SPIM) drives is proposed. The controller effectively integrates backstepping (BS) control for the outer loops with a novel adaptive higher-order sliding mode (NAHOSM) controller for the inner current loop. This control strategy also proposes load disturbance estimator using a predictive model to estimate the component required for the BS_NAHOSM control strategy to help identify and proactively eliminate disturbances. The proposed approach demonstrates robust and stable performance under parameter uncertainties and load disturbances, while significantly reducing the chattering phenomenon. Simulation results obtained using MATLAB/Simulink confirm the effectiveness and superiority of the proposed control strategy
Recyclability of PLA and PLA-PBAT Compounds
Get PDFIn this study, mechanical recycling of polylactic acid (PLA) was investigated for up to 10 cycles. As expected, PLAs mechanical properties (tensile strength and modulus, charpy impact strength, heat deflection temperature) decreased after multiple rounds of recycling. Thermal properties and melt flow rate were also measured to examine the effect of reprocessing on the molecular structure. PLA was combined with industrial biopolymer waste (IW) containing polybutylene adipate terephthalate (PBAT) in different ratios to investigate the recyclability of potential biopolymer waste streams. The results showed that the properties (rheological, thermal and structural) of the mixed biopolymer waste stream (containing PLA and PBAT) are highly dependent on the ratios of the different polymers. Mechanical properties changed from brittle to tough when PBAT content was increased. These results can be beneficial for manufacturers and recyclers who are trying to incorporate biopolymers into their processes or who are dealing with different biopolymer waste streams at the same time
Comparison of Structured Light Projection-based Surface Reconstruction Methods
Get PDFIn recent decades, technological advancements and digitalization have led to the emergence of numerous new instruments and measurement techniques in optics. Contactless measurement methods have gained increasing significance, especially since the COVID-19 pandemic. Profilometry, as an optical measurement technique, enables precise and non-destructive surface analysis. Compared to traditional contact-based methods, it offers numerous advantages, making it particularly useful in various fields, especially in medicine. These techniques allow for detailed examination of biological surfaces and tissues without physical contact, which is often crucial for patient safety. They can be applied to analyze skin structure, monitor wound healing, and assess the surface properties of implants and prosthetics while minimizing infection risks and other complications. Beyond medical applications, profilometric techniques are also widely used in the defense industry, materials science, and manufacturing, where accurate and rapid non-contact surface characterization is essential. Our research explores various types of profilometry and their potential applications using different models. The core principle involves projecting structured light onto a surface and capturing the distorted pattern. The reflected light contains the surface's characteristics, allowing its geometry to be reconstructed through image processing. The most used mathematical tools for this are Fourier and wavelet transforms, the latter often being more efficient due to its scaling and shifting properties. Besides these, other integral transforms can also be applied. In this research, we compare and evaluate different integral transform-based profilometric methods to derive useful conclusions
Regression Analysis and Neural Network Model of Working Diameter of Ball-end Mill
Get PDFIn ball-end milling, a clear distinction exists between the nominal and the working (or effective) diameters, particularly when machining free-form surfaces. The working diameter is not constant; instead, it changes dynamically based on several factors, including the surface inclination (AN2), tool diameter (D), depth of cut (ap), and feed direction (Af). Accurately predicting the working diameter is essential for improving surface quality and dimensional accuracy. Three primary approaches are commonly used for this purpose: the geometric model, which analytically describes the geometric relationships between machining parameters and the working diameter; regression analysis, which builds mathematical models from empirical data; and artificial neural network (ANN) models, which are capable of modeling complex, non-linear interactions between multiple input variables and the working diameter. In this study, one geometric model, two types of regression models, and two ANN models were developed and evaluated. Their performance was assessed using a set of statistical measures, including the standard deviation of the prediction error, the coefficient of determination (R2), the root mean square error (RMSE), and the mean absolute percentage error (MAPE). These metrics provided a comprehensive basis for comparing the accuracy and reliability of each approach. The results highlight the strengths and limitations of each method in capturing the variability of the working diameter during ball-end milling of free-form surfaces