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Found 6423 publications

Anisotropic vector hysteresis model applying Everett function and neural network

Amália Iványi Miklós Kuczmann

Publication Name: Physica B Condensed Matter

Publication Date: 2006-02-01

Volume: 372

Issue: 1-2

Page Range: 138-142

Description:

This paper deals with a simulation technique based on neural networks and an identification method to approximate the behavior of vector hysteresis characteristics of ferromagnetic materials. The identification procedure is based on theoretical measured vector Everett functions using Fourier expansion to deal with angle dependence of the measured scalar Everett functions and of the vector Everett functions in the 2D or in the 3D space. Computing afterwards the theoretical measured vector Everett functions for some given directions, the corresponding hysteresis models are approximated by neural networks and are used to build up the vectorial hysteresis model both in isotropic and anisotropic case. The properties of the anisotropic model has been analyzed and shown in figures. For some examples, the first order reversal curves determined from the vectorial model are compared with the corresponding measured curves that have been used to compute the measured scalar Everett functions being the input for the identification procedure. © 2005 Elsevier B.V. All rights reserved.

Open Access: Yes

DOI: 10.1016/j.physb.2005.10.034

FIRST APPLICATION OF AN IMPROVED-RESOLUTION DARK-FIELD MICROSCOPY SETUP, COMBINED WITH A NOVEL DIRECT-STAINING LIVE IMMUNOFLUORESCENCE INVESTIGATION METHOD, VISUALISING THE MOTION OF BORRELIA BURGDORFERI SPIROCHETES

András P. Bózsik Béla P. Bózsik Béla P. Bózsik Béla P. Bózsik

Publication Name: Acta Microscopica

Publication Date: 2024-01-01

Volume: 33

Issue: 1

Page Range: 54-62

Description:

Dark-field microscopy has been increasingly applied in diagnostics in recent years, for example in Lyme borreliosis, due to the growing concerns about the diagnostic utility of standard serological tests. Although the diagnostic value of microscopic methods is still debated due to the lack of proper clinical testing and the definition of the diagnostic cutoff levels, it is important that the spirochetes causing the disease can be visualized from body fluids via dark-field investigation. Additionally, a specific identification of Borrelia is still not routinely possible, visual observation is usually fortified with additional PCR investigations. We are publishing the pictures from the first-time application of an enhanced dark-field illumination technique that improves the resolution and picture quality of digital recordings. The same illumination setup, combined with a novel live staining of Borrelia burgdorferi with cleaned, FITC-labelled anti-Borrelia antibodies, has produced remarkable recordings of the same spirochetes, in natural motion. All experiments were performed on remnant samples of DualDur kit laboratory investigations.

Open Access: Yes

DOI: DOI not available

Sentinels of Sustainability: Practices of Agricultural Farms Clustered in Hungary’s Farmers’ Markets

Károly Kacz Judit Petra Koltai Szabolcs Troján Tamás Vinkóczi Anita Miklósné Varga

Publication Name: Chemical Engineering Transactions

Publication Date: 2024-01-01

Volume: 114

Issue: Unknown

Page Range: 973-978

Description:

The analysis of local farmers' markets (FMs) is an important part of sustainability issues, as the products they offer can guarantee both the proper functioning of local farms and healthy nutrition for inhabitants. The aim of this research is to identify the most important characteristics of FMs small-scale businesses related to agricultural activities based on a convenience sample in Hungary. The database obtained by the questionnaire survey was compiled based on the answers of a total of 220 farm owners/managers. The results were subjected to analysis using a K-means clustering method, which identified four distinct groups of farms with the highest weighting of turnover from agricultural activity. The clustering distinguished beekeeping, arable crop production, animal husbandry, and vegetable and fruit production, which were treated as a separate cluster. The observed differences between the groups indicate that farms primarily engaged in beekeeping and livestock farming have the highest turnover. These findings may be manifested by the group’s member farms in terms of higher professional representation and high-quality products. A noteworthy distribution-related finding is that livestock products exhibit the greatest average distance from the point of origin to the FM, which can be attributed to the sparse geographical location of the production sites. The results could have a considerable consequence for policymakers in informing them about the design of support opportunities and the identification of beneficiary groups.

Open Access: Yes

DOI: 10.3303/CET24114163

Expanded scope of traffic-flow analysis: Entity flow-phase analysis for rapid performance evaluation of enterprise process systems

László Muka G. Lencse

Publication Name: Esm 2006 2006 European Simulation and Modelling Conference Modelling and Simulation 2006

Publication Date: 2006-01-01

Volume: Unknown

Issue: Unknown

Page Range: 94-98

Description:

This paper describes entity-flow phase analysis (EFA) which is a method for fast performance analysis of organisational process systems. EFA, similarly to traffic-flow analysis for communication systems (TFA), uses the combined approach of simulation and numerical methods. In simulation projects initiated to support the design of Information and Communication Technology (ICT) system and Business Process (BP) system in an organisation the parallel analysis of different systems may be efficient. EFA is a promising evaluation method to be applied for systems with determined BP and ICT subsystems in an organisational environment.

Open Access: Yes

DOI: DOI not available

Comparison of Extended and Unscented Kalman Filters with and without Using Mechanical Model for Speed Sensorless Control of Induction Machines

Krisztián Horváth

Publication Name: 2023 18th Conference on Electrical Machines Drives and Power Systems Elma 2023 Proceedings

Publication Date: 2023-01-01

Volume: Unknown

Issue: Unknown

Page Range: Unknown

Description:

In this work, speed sensorless state estimators are compared for induction machine drives. The studied estimators are based on two widely used state-space models. The first one has five state variables and assumes slowly varying rotor speed. In contrast, the second model is augmented by the equation of motion and the load torque is defined as an additional state variable. Due to the nonlinearities, extended and unscented Kalman filters are applied in the case of both models. To compare the parameter sensitivities and the low speed operation of the four state estimators, simulations and experiments are carried out. In addition, the estimators are also tested in speed sensorless closed-loop control structure.

Open Access: Yes

DOI: 10.1109/ELMA58392.2023.10202302

A distance model for safety-critical systems

Miklós Szijártó Gábor Kallos Dietmár Gröger

Publication Name: Periodica Polytechnica Electrical Engineering

Publication Date: 2001-01-01

Volume: 45

Issue: 2

Page Range: 109-118

Description:

In this paper we introduce a new, theoretical model for safety-critical systems in which the distance from the dangerous conditions can be measured. To describe these systems we use besides the graph model Petri nets, too. We illustrate the theoretical discussion with some simple examples.

Open Access: Yes

DOI: DOI not available

Sustainability Factors of Cultural and Creative Industries - The Case Study of a Creative City, Budapest

Petra Kinga Kézai Szandra Gombos

Publication Name: Chemical Engineering Transactions

Publication Date: 2023-01-01

Volume: 107

Issue: Unknown

Page Range: 127-132

Description:

Regarding Cultural and Creative Industries (CCI) concept-related development, an important aspect has arisen and become inevitable in the last few years: sustainability. Although sustainability and creativity are closely linked, it is important to examine the sustainability factors of creative city development from a broader perspective. The present research aims to explore the environmental sustainability of the cultural and creative industry of a Central and Eastern European capital, Budapest, through a literature review and then two case studies of environmentally sustainable CCI companies. The aim of the paper is to show the gap in the literature regarding the environmental sustainability of the CCI sector, despite its significance, and present two case studies of how environmental sustainability can appear in two CCI companies, showing a best practice. The literature analysis has shown that the interpretation of CCIs' sustainability and the comparability of the sector in the region under study are hampered by the wide variation in methodologies for measuring the sustainability of CCIs. In the case of Budapest, within the study’s 13 y reach, research has shown that Budapest plays a significant role in CCIs, although it also struggles with the issues of sustainability. The two case studies can show role models for environmentally sustainable CCIs by making sustainability the scope and basis of their operation.

Open Access: Yes

DOI: 10.3303/CET23107022

Comparison of Hydrogen Related Policies and Achievements between Latin America and Europe

András Torma Péter Németh Susana Pérez Milicua Mendoza

Publication Name: Chemical Engineering Transactions

Publication Date: 2024-01-01

Volume: 114

Issue: Unknown

Page Range: 991-996

Description:

Hydrogen, and green hydrogen will be one of the dominant energy sources of the future, the application of which will support the achievement of existing decarbonisation targets and contribute to the smooth integration of renewables into energy infrastructure based on its energy storage characteristics. The goal of this study is to compare hydrogen-related policies and achievements between Latin America and Europe. The research employs a comprehensive literature review to assess existing policy frameworks, technological advancements, and economic impacts in both regions. Preliminary findings indicate that while Europe has developed a more structured and well-funded hydrogen economy, Latin America shows great potential due to its renewable energy resources but lags in policy coordination and investment. The significance of this work lies in identifying key gaps and opportunities, aiming to provide policy recommendations that can enhance hydrogen development strategies in both regions, ultimately contributing to global decarbonization efforts.

Open Access: Yes

DOI: 10.3303/CET24114166

Exploring the rosmarinic acid profile of dark chocolate fortified with freeze-dried lemon balm extract using conventional and non-conventional extraction techniques

E. Lakatos V. Kapcsándi Székelyhidi Rita Beatrix Sik Zsolt Ajtony

Publication Name: Lwt

Publication Date: 2021-07-01

Volume: 147

Issue: Unknown

Page Range: Unknown

Description:

The present study evaluated the feasibility of the fortification of dark chocolate with a freeze-dried lemon balm extract rich in rosmarinic acid (RA). Given the food matrix used, it was necessary to develop an analytical and extraction method for RA determination in fortified chocolate. A simple and efficient reversed-phase high-performance liquid chromatography method (RP-HPLC) has been developed for the estimation of RA in dark chocolate. The validity of the method was demonstrated by evaluating the system suitability, linearity, precision, accuracy, the limit of detection, and limit of quantification. The extraction of RA from chocolate was optimized using maceration with shaking (MACS) and microwave-assisted extraction (MAE). The experimental conditions, namely solvent type and extraction time, were optimized using the one-factor-at-a-time methodology. Under the optimized conditions, the proposed method showed good recovery within 95% and acceptable reproducibility with intra- and inter-day relative standard deviations of <2.3%. The method was linear from 5 to 800 μg/mL with a determination coefficient of 1.000. Moreover, the functional chocolate showed a homogeneous active ingredient distribution and retained its RA amount since no significant difference was observed during storage. Overall, the present method was successfully applied to determine RA content in fortified chocolate.

Open Access: Yes

DOI: 10.1016/j.lwt.2021.111520