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Publications - 6374

Experimental analysis and numerical modelling of contact damping

Balázs Pere B. Magyar R. Wohlfart R. Zana G. Stépán G. Csernák

Publication Name: Journal of Sound and Vibration

Publication Date: 2020-10-13

Volume: 484

Issue: Unknown

Page Range: Unknown

Description:

The energy dissipation in assembled metal structures is mainly related to various physical phenomena – usually modelled as dry friction – on the contact surfaces. However, the reliable numerical modelling of assemblies is a challenging task due to the complexity of the contact mechanisms. To fit the models to experimental results, it is beneficial if the material damping can be separated from the contact damping. The paper presents measurement results aiming to distinguish material damping from the damping related to the contact between the conforming surfaces of assembled machine parts. To evaluate the role of contact in damping and to find a connection between the contact-related increase of modal damping and the mode shapes, the modal damping ratios of a monolithic body and a shrink-fitted assembly are compared. It is demonstrated that the contact damping is linear in the examined case. Based on the experiments, a finite element (FE) model was developed that does not apply computationally expensive contact algorithms. The FE model was able to reproduce the measured modal damping values of the assembled structure at all the natural frequencies that fell in the frequency range of the measurement. This result is achieved by fitting only a single damping parameter. The research work is motivated by metal cutting, where the damping of the machine-tool-workpiece loop plays a key role in the stability of the process, particularly in case of high speed machining.

Open Access: Yes

DOI: 10.1016/j.jsv.2020.115544

Multiple-solution heat exchanger network synthesis for enabling the best industrial implementation

Ákos Orosz Ferenc Friedler

Publication Name: Energy

Publication Date: 2020-10-01

Volume: 208

Issue: Unknown

Page Range: Unknown

Description:

The synthesis of heat recovery networks traditionally results in an optimal or suboptimal solution for the supplied set of streams and simplifying assumptions. In the current work, the assumption of a single optimal solution is replaced by the goal of generating an ordered set of optimal or quasi-optimal networks. This enables industrial engineers to further select the solution most suitable for detailed design and practical implementation. The problem is formulated for and solved by an extension of the P-graph framework for combinatorial process network optimization. The presented method for HEN synthesis generates a list of solutions ranked by the Total Annualized Cost. In addition to the feasibility, all list elements also feature a degree of heat recovery ranging from the thermodynamic maximum, down to a specified margin allowing accounting for the energy-capital trade-off. The current method is illustrated with three case studies. The obtained results demonstrate optimal solutions that cannot be generated by the Pinch-based methods or the stage-wise superstructure approaches. The proposed parameters, an upper limit on the number of heat exchangers per process stream and a maximum relaxation of utility demand compared to the Pinch targets, allow performing parametric evaluations of the resulting solutions.

Open Access: Yes

DOI: 10.1016/j.energy.2020.118330

ACTN3 rs1815739 and BDNF rs6265 Polymorphisms May Not Be Associated with Handgrip Strength in Elite Wrestlers

Mehmet A. Ergun Hasan H. Kazan David Varillas-Delgado Celal Bulgay Ebru Dolu Savaş Orhan Luca Paolo Ardigò Attila Szabo

Publication Name: Genes

Publication Date: 2026-05-01

Volume: 17

Issue: 5

Page Range: Unknown

Description:

Background/Objectives: Handgrip strength (HGS) is a widely used indicator of upper-limb muscular strength and a practical proxy for neuromuscular performance across both clinical and athletic contexts. Although HGS is heritable, evidence supporting specific genetic contributors in elite athletes remains limited. Thus, the present study investigated the associations of two functional polymorphisms, BDNF rs6265 (p.Val66Met) and ACTN3 rs1815739 (p.R577X), with HGS performance in elite wrestlers, integrating neuromuscular and muscle fiber-related biological pathways. Methods: The present study included 613 subjects (56 elite male wrestlers (mean age: 22.35 ± 5.34 years; training experience: 13.40 ± 3.85 years) and 557 healthy individuals drawn from a public database). HGS measurements were performed using a digital hand dynamometer. Results: Genotyping was performed on DNA extracted from peripheral blood using a high-density single nucleotide polymorphism (SNP) array. Neither BDNF rs6265 nor ACTN3 rs1815739 was significantly associated with HGS in elite wrestlers (p > 0.05), and effect estimates were negligible. In addition, ACTN3 rs1815739 genotype and allele frequencies were comparable between wrestlers and the reference population, indicating no enrichment of this variant in the elite cohort. In this sample of elite male wrestlers, BDNF rs6265 and ACTN3 rs1815739 were not associated with HGS, and ACTN3 rs1815739 was not enriched relative to a national reference population. Conclusions: These findings suggest no detectable effects of single candidate variants on HGS under the current study design in highly trained athletes; however, this interpretation should be made cautiously given cohort-specific limitations and does not preclude their potential contribution within the broader polygenic architecture of strength-related traits. Future research employing larger, well-powered, and multi-cohort designs and polygenic approaches is warranted to further elucidate the genetic basis of strength phenotypes.

Open Access: Yes

DOI: 10.3390/genes17050559

Taxonomic contribution to knowledge of the oribatid mite genus Achipteria (Acari, Oribatida, Achipteriidae)

Sergey G. Ermilov Jenő Kontschán

Publication Name: International Journal of Acarology

Publication Date: 2025-01-01

Volume: 51

Issue: 2

Page Range: 81-87

Description:

The oribatid mite family Achipteriidae is recorded in the Dominican Republic for the first time. A new species of the genus Achipteria—A. (Izuachipteria) dominicanensissp. nov.—is described, based on adults collected from leaf litter in a mixed forest. The species is characterized by the morphology of the lamella (triangular distally, without strong lateral tooth), the location of the lamellar seta (on ventral side of the lamella), the length of the bothridial seta (long), the ornamentation and morphology of the pteromorph (partially striate, with lateral tooth), the number of the leg claws (one), and the absence of the notogastral saccules. The taxonomic status of the subgenera Achipteria (Cubachipteria), A. (Hokkachipteria), and A. (Izuachipteria) is discussed. An identification key, distribution, and habitat of the known representatives of Achipteria (Izuachipteria) are presented.

Open Access: Yes

DOI: 10.1080/01647954.2024.2439799

Hungarian experiences of the transition from traditional work to telework1

No authors available

Publication Name: Transformations in Business and Economics

Publication Date: 2021-01-01

Volume: 20

Issue: 3

Page Range: 168-182

Description:

The global outbreak of the COVID-19 epidemic has radically transformed people’s daily lives since the spring of 2020. In addition to the direct health consequences of the virus, the epidemic has had a significant impact on the functioning of society, people’s lifestyles and has also had a fundamental impact on the world of work. The year 2020 marked a breakthrough in the spread of telework and “home office” work in Hungary, as this form of work was one of the necessary tools in the fight against the COVID-19 epidemic in order to reduce the number of personal contacts. Both employers and the masses of employees were able to experience the pros and cons of this. This period can be therefore considered as the main challenge of teleworking and working from home, which is undoubtedly caused by the COVID-19 epidemic. The research aims to answer the question of the impact of telework on the daily lives of Hungarian workers. In international comparison, the proportion of teleworkers in Hungary was low before the pandemic. As a result, a great many have experienced a drastic transition from traditional work to teleworking. The given questionnaire survey also confirmed that a significant proportion of employees had difficulties with teleworking at the beginning of the transition. These difficulties were mainly due to the fact that they were not technically prepared and that their daily routine, which they had become accustomed to in their traditional work, had been changed.

Open Access: No

DOI: DOI not available

Distance learning system established for teachers of hungarian language and culture in diaspora with the support of MaxWhere 3D VR

Attila Pongracz Balint Lampert Viktória Kövecses-Gősi Ildiko Lorincz

Publication Name: 11th IEEE International Conference on Cognitive Infocommunications Coginfocom 2020 Proceedings

Publication Date: 2020-09-23

Volume: Unknown

Issue: Unknown

Page Range: 331-336

Description:

At the Apáczai Csere János Faculty of Széchenyi István University we had the opportunity to create a distance learning system that helps colleagues in the diaspora to teach Hungarian as a foreign language. Free interface became available to educators interested in the programme in May 2020. Distance learning is realized via Moodle of the university's VR learning system, complemented by the possibilities provided by MaxWhere 3D VR learning spaces. In the process of developing the distance learning system, professional, content-related and technical needs were assessed with the help of focus group interviews. The present study aims to present this process as well as the theoretical and practical background of the establishment of this distance learning system.

Open Access: Yes

DOI: 10.1109/CogInfoCom50765.2020.9237853

The impact of socio-economic factors on the dynamics of social pressure in Kazakhstan

Laszlo Vasa Assel Bekbossinova Meiirzhan Abdykadyr Sabden Orazaly

Publication Name: Problems and Perspectives in Management

Publication Date: 2025-01-01

Volume: 23

Issue: 4

Page Range: 61-74

Description:

The purpose of the study was is to assess the impact of key factors (including employment, income, poverty level, prices and social support) on the dynamics of social pressure in Kazakhstan. The analysis covered the period from 2014 to 2024 and utilized official data. The methodology combines entropy-based ranking of indicators, calculation of the Socio-Economic Pressure Index (SEPI), Social Stability Index (SSI), and Social Inertia Index (SII), as well as phase-portrait visualization. The entropy ranking revealed that the share of population below the food basket cost (di = 0.71; Wi = 0.2381) and housing assistance (di = 0.516; Wi = 0.1728) had the highest variability and the strongest influence on SEPI. Moreover, SEPI rose from 0.0967 in 2014 to its peak in 2023 – over 20 times higher – before falling to 0.53 in 2024. SSI dropped from 4.94 in 2017 to 0.44 in 2023, with minimal adaptive capacity, and partial recovery to 1.87 in 2024. There was recorded instability of positive changes and a high likelihood of renewed pressure due to the lowest value of SII (–3.24) in 2024. Thus, long-term stability and a reduction in the social sphere’s susceptibility to external and internal shocks require integrated policy measures that combine targeted support, income regulation, and adaptive governance.

Open Access: Yes

DOI: 10.21511/ppm.23(4).2025.05

The mechanical and the geometrical state of railway vehicle carriages

No authors available

Publication Name: Proceedings - 25th Danubia-Adria Symposium on Advances in Experimental Mechanics, DAS 2008

Publication Date: 2019-01-01

Volume:

Issue:

Page Range: 181-182

Description:

Open Access: No

DOI: DOI not available

Effects of Fermented Pea–Wheat Ingredient Inclusion in Soybean Meal-Replacement Diets on Intestinal Adaptation, Gut Microbiota, and Fecal Consistency in Weaned Piglets

Tamás Tóth Alex Váradi Eszter Kaszab Zoltán Somogyi Botond Alpár László Varga

Publication Name: Animals

Publication Date: 2026-05-01

Volume: 16

Issue: 10

Page Range: Unknown

Description:

Weaning disrupts intestinal structure and function in piglets and frequently results in post-weaning diarrhea, highlighting the need for effective nutritional alternatives to medicinal feed additives. This study evaluated non-fermented field peas and diets containing different inclusion levels of a fermented pea–wheat ingredient as substitutes for soybean meal in restricted liquid diets for weaned piglets. Fifty-six piglets were assigned to four dietary treatments for 14 days after weaning: non-fermented soybean meal, non-fermented peas, partial inclusion of the fermented pea–wheat ingredient, or full inclusion of the fermented pea–wheat ingredient. Fecal consistency, plasma inflammatory cytokines, small-intestinal morphology, crypt cell proliferation, and intestinal microbiota composition were assessed. Plasma interleukin-1β, interleukin-6, and tumor necrosis factor-α remained low and did not differ among treatments, indicating no measurable systemic inflammatory response. Diets containing the fermented pea–wheat ingredient were associated with differences in early intestinal morphology, particularly villus height on day 4 after weaning. Treatment- and segment-specific variation was also observed in crypt cell proliferation. Microbiota analysis showed differences in community composition among treatments, with diets containing the fermented pea–wheat ingredient associated with a higher relative abundance of lactic acid-producing genera. At the pen level, full inclusion of the fermented pea–wheat ingredient was consistently associated with low fecal scores, whereas partial inclusion was associated with higher fecal scores throughout the study period. Overall, these findings suggest that, under the controlled conditions of this study, diets containing the full inclusion level of the fermented pea–wheat ingredient were associated with indicators of intestinal adaptation and consistently low pen-level fecal scores. Further studies with replicated pen designs, longer-term performance evaluation, and functional analyses are needed before practical recommendations can be made.

Open Access: Yes

DOI: 10.3390/ani16101526