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Publications - 6289

Frequency- and Temperature-Dependent Uncertainties in Hysteresis Measurements of a 3D-Printed FeSi wt6.5% Material

Tamas Orosz B. Kocsis

Publication Name: Sensors

Publication Date: 2024-05-01

Volume: 24

Issue: 9

Page Range: Unknown

Description:

Additive manufacturing of soft magnetic materials is a promising technology for creating topologically optimized electrical machines. High-performance electrical machines can be made from high-silicon-content FeSi alloys. Fe-6.5wt%Si material has exceptional magnetic properties; however, manufacturing this steel with the classical cold rolling methodology is not possible due to the brittleness of this material. Laser powder bed fusion technology (L-PBF) offers a solution to this problem. Finding the optimal printing parameters is a challenging task. Nevertheless, it is crucial to resolve the brittleness of the created materials so they can be used in commercial applications. The temperature dependence of magnetic hysteresis properties of Fe-6.5wt%Si materials is presented in this paper. The magnetic hysteresis properties were examined from 20 °C to 120 °C. The hysteresis measurements were made by a precision current generator–based hysteresis measurement tool, which uses fast Fourier transformation–based filtering techniques to increase the accuracy of the measurements. The details of the applied scalar hysteresis sensor and the measurement uncertainties were discussed first in the paper; then, three characteristic points of the static hysteresis curve of the ten L-PBF-manufactured identical toroidal cores were investigated and compared at different temperatures. These measurements show that, despite the volumetric ratio of the porosities being below 0.5%, the mean crack length in the samples is not significant for the examined samples. These small defects can cause a significant 5% decrement in some characteristic values of the examined hysteresis curve.

Open Access: Yes

DOI: 10.3390/s24092738

A coupled impact of different management and soil moisture on yield of winter wheat (Triticum aestivum L.) in dry conditions at locality Mezoföld, Hungary

G. Milics

Publication Name: Journal of Hydrology and Hydromechanics

Publication Date: 2021-03-01

Volume: 69

Issue: 1

Page Range: 76-86

Description:

Variable rate technology (VRT) in nutrient management has been developed in order to apply crop inputs according to the required amount of fertilizers. Meteorological conditions rarely differ within one field; however, differences in soil conditions responding to precipitation or evaporation results within field variations. These variations in soil properties such as moisture content, evapotranspiration ability, etc. requires site-specific treatments for the produced crops. There is an ongoing debate among experts on how to define management zones as well as how to define the required amount of fertilizers for phosphorus and nitrogen replenishment for winter wheat (Triticum aestivum L.) production. For management zone delineation, vegetation based or soil based data collection is applied, where various sensor technology or remote sensing is in help for the farmers. The objective of the study reported in this paper was to investigate the effect of soil moisture data derived from Sentinel-2 satellite images moisture index and variable rate phosphorus and nitrogen fertilizer by means of variable rate application (VRA) in winter wheat in Mezoföld, Hungary. Satellite based moisture index variance at the time of sowing has been derived, calculated and later used for data comparison. Data for selected points showed strong correlation (R2 = 0.8056; n = 6) between moisture index and yield, however generally for the whole field correlation does not appear. Vegetation monitoring has been carried out by means of NDVI data calculation. On the field level, as indicated earlier neither moisture index values at sowing nor vegetation index data was sufficient to determine yield. Winter wheat production based on VRA treatment resulted significant increase in harvested crop: 5.07 t/h in 2013 compared to 8.9 t/ha in 2018. Uniformly managed (control) areas provided similar yield as VRA treated areas (8.82 and 8.9 t/ha, respectively); however, the input fertilizer was reduced by 108 kg/ha N and increased by 37 kg/ha P.

Open Access: Yes

DOI: 10.2478/johh-2020-0039

Effect of the energy, carbohydrate, protein, and amino acid profile on the quality of ovum and embryo in cattle

Toth Tarnas Papp Peter

Publication Name: Magyar Allatorvosok Lapja

Publication Date: 2021-03-01

Volume: 143

Issue: 3

Page Range: 145-159

Description:

In the present review, the authors summarize the potential effects of energy, carbohydrate, protein, and amino acid supplementation on the reproductive performance of dairy and beef cattle, focusing on the development and quality of the ovum and the preimplantation embryo. Excess dry matter and energy intake can have a positive or negative effect on the development of the preovulatory follicle and embryo, depending on the body condition, the physiological status and the actual milk production of the cows. In this review, the importance of hormones (e.g. insulin, insulin-like growth factor and leptin) were taken into consideration regarding their role in the reproductive performance of the dairy and beef cattle. Feeding high levels of non-fibre car-bohydrates (NFC) can lead to hyperinsulinaemia and deteriorating results in embryo production. It is well-known that the type and composition of carbohydrates in the diet alter several physiological processes, but there is no exact information about the effects of carbohydrate-composition on the follicular development and embryo quality. High protein intake, particularly the rumen degradable protein (RDP), increases plasma urea concentration. High urea levels can lead to poor reproductive performance in cattle. Urea has a direct negative effect on the final stages of follicular development and indirectly alters embryonic development by decreasing pH in the uterine fluid. The levels of certain amino acids in the lumen of the pregnant uterus are significantly higher than before pregnancy. Methionine, lysine and histidine have the greatest rise at the presence of the preimplantation embryo. Feeding rumen-protected forms of these amino acids can positively alter embryo production, but further investigation is needed in this field. The authors deem that more research is needed to lay effective feeding strategies for the success of embryo production.

Open Access: Yes

DOI: DOI not available

Virtual localization by blind persons

György Wersényi

Publication Name: AES Journal of the Audio Engineering Society

Publication Date: 2012-07-01

Volume: 60

Issue: 7-8

Page Range: 568-579

Description:

Localization performance and spatial hearing abilities of blind persons are complex issues. In everyday life we rely on the "fact" that blind people can hear better, without thinking of what "better" means. Localization performance depends on many parameters such as properties of the excitation signal, environmental conditions, individual aspects, and visual influence. Our goal was to create a virtual environment aimed at helping the blind community use personal computers. In developing this environment we were concerned to cover technical and hearing related questions, as well as human factors. At first, this project included sighted subjects and basic properties of the virtual audio system and the applied HRTFs were tested. Subsequently, blind persons have been involved and comparative measurements performed using the same equipment and selected localization tasks. Twenty-eight blind person's localization performances were tested and compared with the results of 40 sighted subjects in a virtual audio environment. Blind subjects tended to be better in detecting movements in the horizontal plane around the head, localizing static frontal audio sources, and orientation in a 2-D virtual audio display. On the other hand, sighted subjects performed better identifying ascending sound sources in the vertical plane and detecting static sources in the back. In-the-head localization error rates and MAA results appeared to be about the same for both groups. The evaluation was also supported by some informal questions.

Open Access: Yes

DOI: DOI not available

5G Networks in the Value Chain

John G. Keogh Abderahman Rejeb

Publication Name: Wireless Personal Communications

Publication Date: 2021-03-01

Volume: 117

Issue: 2

Page Range: 1577-1599

Description:

As Information and Communication Technologies are evolving rapidly and at an exponential pace‚ businesses are forced to cope with the latest trends in innovation and to respond to emerging needs and opportunities. The constant digitization and process automation (digitalization) of supply chains call for the consideration of innovative services to sustain value chain efficiency and effectiveness. Given the approaching technological developments‚ the new network upgrades embodied in 5G networks raises several high expectations along the value chain. This paper recognizes the critical role of 5G telecommunications to support several value chain activities and create value propositions that would not be possible with existing network generations. To this end‚ Porter’s value chain model is applied and comprehensively discussed to highlight the potential areas that could be facilitated by 5G telecommunications.

Open Access: Yes

DOI: 10.1007/s11277-020-07936-5

Factors Affecting Humanitarian Resilience: A Mediating Approach of Community Engagement

Laszlo Vasa Md Billal Hossain Nassar Samia Zsuzsanna Toth Naarne

Publication Name: Decision Making Applications in Management and Engineering

Publication Date: 2025-01-01

Volume: 8

Issue: 1

Page Range: 108-131

Description:

This paper examines the factors that influence humanitarian resilience, explicitly focusing on the mediating role of community engagement. Humanitarian resilience is a critical aspect of disaster management and response, and understanding the underlying factors and the role of community engagement in enhancing resilience is paramount This study investigates the multifaceted factors influencing humanitarian resilience among the youth population of the Gaza Strip, focusing on the variables of humanitarian aid funding, logistical support, and humanitarian personnel. Employing quantitative research methodology and Structural Equation Modelling (SEM) techniques, we explore the mediating role of community engagement in shaping the dependent variable of humanitarian resilience. In a sample of 429 youth residing in the Gaza Strip, our research assesses the direct impacts of funding humanitarian assistance, logistical support, and the presence of humanitarian personnel on the participants' resilience levels. Furthermore, we examine how community engagement mediates the relationship between these factors and the overall level of humanitarian resilience. This innovative approach aims to provide a comprehensive understanding of the intricate dynamics in the context of humanitarian assistance in the Gaza Strip. The findings of this study hold significant implications for policymakers and humanitarian organizations operating in conflict-affected regions. By elucidating the mediating influence of community engagement, we shed light on potential strategies to enhance the resilience of individuals and communities in the face of adversity, ultimately contributing to the effectiveness of humanitarian efforts in the Gaza Strip and similar contexts worldwide.

Open Access: Yes

DOI: 10.31181/dmame8120251106

Numerical analysis of a 2D vector hysteresis measurement system under construction

Miklós Kuczmann

Publication Name: Journal of Electrical Engineering

Publication Date: 2006-12-01

Volume: 57

Issue: 8 SUPPL

Page Range: 44-47

Description:

This paper deals with the numerical analysis of a vector hysteresis measurement system which is under construction. The aim is to build up a single sheet tester with round shaped specimen. The goal of simulations is to find out the main features of the measurement system. The 3D finite element method (FEM) with tetrahedral mesh has been applied for investigations of the nonlinear eddy current field problem. The characteristic of the magnetic material has been taken into account by the isotropic vector Preisach model. The nonlinearity has been handled by the polarization method and the nonlinear system of equations has been solved by the fixed point technique. The first results are presented in this work. © 2006 FEI STU.

Open Access: Yes

DOI: DOI not available

Utilizing the inherent electrolysis in a chip-based nanoelectrospray emitter system to facilitate selective ionization and mass spectrometric analysis of metallo alkylporphyrins

Vilmos Kertesz Gary J. Van Berkel

Publication Name: Analytical and Bioanalytical Chemistry

Publication Date: 2012-04-01

Volume: 403

Issue: 2

Page Range: 335-343

Description:

A commercially available chip-based infusion nanoelectrospray ionization system was used to ionize metallo alkylporphyrins for mass spectrometric detection and structure elucidation by mass spectrometry. Different ionic forms of model compounds (nickel (II), vanadyl (II), copper (II), and cobalt (II) octaethylporphyrin) were created by using two different types of conductive pipette tips supplied with the device. These pipette tips provide the conductive contact to solution at which the electrolysis process inherent to electrospray takes places in the device. The original unmodified, bare carbon-impregnated plastic pipette tips were exploited to intentionally electrochemically oxidize (ionize) the porphyrins to form molecular radical cations for detection. Use of modified pipette tips, with a surface coating devised to inhibit analytemass transport to the surface or slow the kinetics of the analyte electrochemical reactions, was shown to limit the ionic species observed in the mass spectra of these porphyrins largely, but not exclusively, to the protonated molecule. Under the conditions of these experiments, the effective upper potential limit for oxidation with the uncoated pipette tip was 1.1 V or less, and the coated pipette tips effectively prevented the oxidation of analytes with redox potentials greater than about 0.25 V. Product ion spectra of either molecular ionic species could be used to determine the alkyl chain length on the porphyrin macrocycle. The utility of this electrochemical ionization approach for the analysis of naturally occurring samples was demonstrated using nickel geoporphyrin fractions isolated from Gilsonite bitumen. Acquiring neutral loss spectra as a means to improve the specificity of detection in these complex natural samples was also illustrated. © Springer-Verlag (outside the USA) 2012.

Open Access: Yes

DOI: 10.1007/s00216-011-5676-x

Mapping quality linkages based on tacit knowledge

T. B. Ladinig Gyula Vastag

Publication Name: International Journal of Production Economics

Publication Date: 2021-03-01

Volume: 233

Issue: Unknown

Page Range: Unknown

Description:

A structured conceptualization method, concept mapping, is applied to visualize the conceptual domain of explicit and tacit quality linkages in a complex, causally ambiguous production system of a premium automotive OEM. Experts, intimately familiar with all facets of the conceptual domain, defined sources of quality problems and rated their impact on product quality. These inputs, formative measures for a latent construct, were used to create concept maps and clusters for the sources of quality problems. Differences and disagreements between subgroups were highlighted by pattern matching. The concept map and the preferred cluster solution, based on user-defined measures, served as inputs in the development of a causal loop diagram and an action plan for better resource allocation to specific improvement activities. The approach, using formative rather than the more commonly used reflective indicators, uses key informants and explanation building processes of high internal validity. In the spirit of the “proximal similarity model,” the presented methodology is also highly transferable to similar settings of other automotive OEMs and beyond.

Open Access: Yes

DOI: 10.1016/j.ijpe.2020.108006