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Found 6374 publications

Machine learning models for the elastic-critical buckling moment of sinusoidal corrugated web beam

Andreas Müller Nurullah Bektaş G. Hajdú

Publication Name: Results in Engineering

Publication Date: 2024-09-01

Volume: 23

Issue: Unknown

Page Range: Unknown

Description:

The torsional stiffness of I-beams with sinusoidal corrugated web is higher than that of flat web beams and the accuracy of the available hand-calculation methods to determine the elastic critical lateral-torsional buckling moment depends on the geometrical parameters of the beam and the web corrugation. This study proposes different machine learning models to determine the elastic lateral-torsional buckling moments of corrugated web beams. Various machine-learning algorithms such as Decision Tree, Random Forests, Gradient Boosting, Support Vector Regression, Catboost, and Deep Neural Network were employed to develop and train for predicting the elastic-critical lateral-torsional buckling moments of I-beams with corrugated web. An extensive dataset with 2250 pieces was constructed using linear buckling analyses on full-shell finite element models to determine the elastic-critical buckling moment of simply supported beams with sinusoidal web corrugation. Based on the statistical parameters of the predicted and test data, the accuracy and safety assessment of the different machine learning models are examined. The accuracy of the available hand-calculation methods is also investigated. The results of the parametric study showed that the overall performance of the different machine learning models is promising, although, not all are directly suited for the described problem.

Open Access: Yes

DOI: 10.1016/j.rineng.2024.102371

Development of a low-fat lactose-free dairy spread containing viable lactic acid bacteria – Part 2: Texture analysis and sensory evaluation

Gábor Kátay László Varga

Publication Name: Elelmiszervizsgalati Kozlemenyek

Publication Date: 2019-01-01

Volume: 65

Issue: 3

Page Range: 2573-2588

Description:

The objective of our work was to compare the main texture characteristics of the low-fat (30%), lactose-free dairy spread developed by us, containing viable lactic acid bacteria, and those of commercially available dairy spreads by an objective, reproducible, instrumental test, and then to assess the expected market reaction to our new product. The results of the rheological tests have shown that, in terms of its texture, our lactose-free dairy spread is similar to currently commercially available similar dairy products of adequate quality. Compared to 25 to 39% fat products, it is neither softer, nor stickier, its spreadability is close to that of usual dairy spreads. The judges (250 people) found the flavor and texture of the developed product significantly better (P<0.05) than those of one of the traditional dairy spreads that has been available in stores for a long time. However, in terms of spreadability, the latter dairy product was found to be superior (P<0.05). It was found that our new product could be received well when placed on the market, however, it should be emphasized during its introduction that, in addition to the ideal texture characteristics and nutritional physiology properties of the well-known and popular dairy spreads, it also has added functional benefits since it is lactose-free and contains viable lactic acid bacteria.

Open Access: Yes

DOI: DOI not available

DEM analysis of crushing evolution in cemented granular materials during pile penetration

Majid Movahedi Rad M. Amine Benmebarek

Publication Name: Computers and Geotechnics

Publication Date: 2023-09-01

Volume: 161

Issue: Unknown

Page Range: Unknown

Description:

The present study demonstrates that the 3D discrete-element method provides a practical model approach to visualize the cemented grain crushing evolution under pile penetration. A combined method using a rigorous breakage criterion based on octahedral shear stress (OSS) was implemented in the particle flow code PFC3D. First, the pile penetration is simulated by considering the grains as uncrushable with a screening of highly stressed grains exceeding the threshold defined by the OSS failure condition. Then, the simulation is repeated where crushable agglomerates replace the highly stressed grains. This method is more accurate than the replacement method and more efficient than the agglomerate method. A quarter of the numerical model was considered after validation to achieve an acceptable computational time for parametric studies. Parametric investigations were performed on the effects of particle crushing, boundary conditions, pile tip shape, and pile penetration velocity on the penetration resistance behavior. In agreement with the observations of the physical calibration chamber, the present results indicate that the proposed modeling approach is reliable in reproducing the concentration of crushed granular material particles in the vicinity of the pile tip and shaft. In addition, grain crushing has been found to reduce both penetration and shaft resistance.

Open Access: Yes

DOI: 10.1016/j.compgeo.2023.105631

Optimization of the prediction of second refined wavelet coefficients in electron structure calculations

Brigita Sziova János Pipek Szilvia Nagy

Publication Name: Open Physics

Publication Date: 2016-01-01

Volume: 14

Issue: 1

Page Range: 643-650

Description:

In wavelet-based solution of eigenvalue-type differential equations, like the Schrödinger equation, refinement in the resolution of the solution is a costly task, as the number of the potential coefficients in the wavelet expansion of the solution increases exponentially with the resolution. Predicting the magnitude of the next resolution level coefficients from an already existing solution in an economic way helps to either refine the solution,or to select the coefficients, which are to be included into the next resolution level calculations, or to estimate the magnitude of the error of the solution. However, after accepting a solution with a predicted refinement as a basis, the error can still be estimated by a second prediction, i.e., from a prediction to the second finer resolution level coefficients. These secondary predicted coefficients are proven to be oscillating around the values of the wavelet expansion coefficients of the exact solution. The optimal averaging of these coefficients is presented in the following paper using a sliding average with three optimized coefficients for simple, one-dimensional electron structures.

Open Access: Yes

DOI: 10.1515/phys-2016-0063

Parasitological Examination of the Digestive System of Wild Boar from a Practical Point of View—Endoparasitological Sampling under Field Conditions

Alexandra Juhász Csaba Farkas Balázs Fekete Egri Borisi

Publication Name: Methods and Protocols

Publication Date: 2024-08-01

Volume: 7

Issue: 4

Page Range: Unknown

Description:

From 2015 to 2023, we conducted a comprehensive study in the 11,893-hectare hunting area managed by the Marcal-Bitvaközi Hunting Company, characterised by its substantial wild boar population. The research was carried out across various settings, including a free-range wild boar garden during large-scale hunts and free-living areas during individual hunts. We examined 216 wild boars in total, with 173 individuals from free-living areas and 43 from free-range areas. Throughout the sample collection process, we encountered numerous technical challenges that are infrequently detailed in the professional literature, often mentioned only tangentially. This oversight in existing publications neglects the significance of addressing field sampling difficulties, which are crucial for ensuring the precision and accuracy of research. This paper details the equipment requirements, sampling methodologies, and practical solutions to streamline fieldwork. While our primary focus was on endoparasitic infections of the stomach and small intestine, the described methodologies and findings are broadly applicable to research involving all internal organs.

Open Access: Yes

DOI: 10.3390/mps7040065

The effect of background and outlier subtraction on the structural entropy of two-dimensional measured data

Brigita Sziova Levente Solecki Szilvia Nagy

Publication Name: International Journal of Reasoning Based Intelligent Systems

Publication Date: 2020-01-01

Volume: 12

Issue: 3

Page Range: 200-209

Description:

For colonoscopy images the main information is in the fine structure of the surface of the bowel or colorectal polyps, similarly to the case of combustion engine cylinder surface scans, where the grooving and wear can be detected from the fine pattern superposed to a cylinder curvature. In both cases appear outliers, colonoscopy images have many reflections, whereas the roughness scanners detect small dust particles as well as the micron scale vibrations from the environment. The method presented in this paper takes care of both the problems using histogram stretching together with a special type of filtering. Also, masks are introduced in order to control the effect of the operators. The effects of the processing steps on the structural entropy of the image is also studied, as structural entropies are used in characterisation of the images. By removing the background makes the structural entropies much smaller, and by suppressing the outliers the structural entropies increase.

Open Access: Yes

DOI: DOI not available

Driving Strategy Optimization in Experimental Electric Vehicles: A Study on Optimization Algorithms †

Zoltan Pusztai Ferenc Szauter Ferenc Friedler

Publication Name: Engineering Proceedings

Publication Date: 2024-01-01

Volume: 79

Issue: 1

Page Range: Unknown

Description:

In this paper, the driving strategy simulations for a single-seat, lightweight, energy-efficient experimental electric vehicle are introduced. The vehicle’s operation is simulated using a developed measurement-based vehicle model in the simulation environment. The optimization was performed for the UniTrack platform at the ZalaZone proving ground using the algorithms Particle Swarm Optimization (PSO) and Genetic Algorithm (GA), with different optimization settings corresponding to varying iterations and initial population/swarm sizes. A 2.95% difference was observed between the least effective and the best PSO results, where both the number of iterations and swarm size were doubled. This demonstrates the effectiveness of PSO in solving the presented driving strategy problem, even when using fewer iterations and a smaller swarm size.

Open Access: Yes

DOI: 10.3390/engproc2024079042

Memory-sampled data controller for exponential synchronization of Markovian jump neural networks with mixed delays and partially unknown transition probabilities

A. Chandrasekar T. Radhika Hijaz Ahmad A. R. Subhashri M. Kamali

Publication Name: Physica A Statistical Mechanics and Its Applications

Publication Date: 2026-07-15

Volume: 694

Issue: Unknown

Page Range: Unknown

Description:

The current study investigates the exponential synchronization (ES) problem for a class of Markovian jump neural networks (MJNNs), which are susceptible to distributive and additive time-varying delays and are managed by a memory-sampled data controller (MSDC). The transition probabilities in question are thought to be partially unknown. The information of time delay and sampling instants is captured by enhanced Lyapunov-Krasovskii functionals (LKFs). A novel modified integral inequality is utilized, which provides a potent framework for studying dynamical systems, and also made a foundation of this study. Adequate requirements for the ES of proposed system are obtained in the form of linear matrix inequalities (LMIs) by incorporating these integral inequalities. Under these circumstances, the hybrid closed-loop system's mean square input-to-state stability (ISS) is ensured. Lastly, the accuracy of the proposed ISS synchronization mechanism is verified and illustrated with numerical examples.

Open Access: Yes

DOI: 10.1016/j.physa.2026.131587

Disproportionate exposure to urban heat island intensity – The case study of Győr, Hungary

Eszter Szemerédi Sándor Remsei

Publication Name: Hungarian Geographical Bulletin

Publication Date: 2024-03-30

Volume: 73

Issue: 1

Page Range: 17-33

Description:

Extensive research has shown that urbanisation has a profound effect on the local climate system, leading to the formation of urban heat island. Exposure to urban heat islands poses a major health risk, and there is a growing body of literature recognising that urban population groups with particular demographic characteristics living in specific types of residential environments are disproportionately affected. By combining surface urban heat island data from the Global Surface Urban Heat Island Explorer with neighbourhood-level data on demographics and the type of housing, this study assesses disproportionate exposure to surface urban heat island intensity in the city of Győr, Hungary. Results of the study highlight the importance of targeted interventions for environmental justice, especially in areas characterised by housing estates, high population density and high ageing index.

Open Access: Yes

DOI: 10.15201/hungeobull.73.1.2