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Found 6414 publications

Surface modification and wear properties of direct metal laser sintered hybrid tools used in moulds

Imre Fekete József G. Kovács Tamás Ibriksz Mária B. Maros István Hatos Hajnalka Hargitai

Publication Name: Journal of Mechanical Engineering

Publication Date: 2018-01-01

Volume: 64

Issue: 2

Page Range: 121-129

Description:

Injection moulding is one of the most productive plastic forming processes. Product development and the reduction of production time require new solutions in tooling design and manufacturing. Direct metal laser sintering (DMLS) allows moulds to be built with special cooling systems, which offer curved cooling lines that can follow the geometry of the part (conformal cooling). One disadvantage of DMLS, its high cost, can be dramatically reduced with the building of hybrid structures. With conventional tool steels as the base plate and only the special geometry of the part sintered on the top, the final geometry can be manufactured after sintering by conventional process technologies. We produced hybrid structures by direct metal laser sintering maraging steel (MS1) powder onto the surface of commercial mould steels and studied the effect of different heat treatments on porosity, tribological behaviour and the microstructure. The transition zone was also characterized.

Open Access: Yes

DOI: 10.5545/sv-jme.2017.4942

Simulations of higher-order protein organizations using a fuzzy framework

Boldizsár Tüu-Szabó M. Fuxreiter Laszlo T. Koczy

Publication Name: Complexity

Publication Date: 2018-01-01

Volume: 2018

Issue: Unknown

Page Range: Unknown

Description:

Spatiotemporal regulation of the biochemical information is often linked to supramolecular organizations proteins and nucleic acids, the driving forces of which have yet to be elucidated. Although the critical role of multivalency in phase transition has been recognized, the organization principles of higher-order structures need to be understood. Here, we present a fuzzy mathematical framework to handle the heterogeneity of interactions patterns and the resultant multiplicity of conformational states in protein assemblies. In this model, redundant binding motifs can establish simultaneous and partial interactions with multiple targets. We demonstrate that these multivalent, weak contacts facilitate polymer formation, while recapitulating the observed valency-dependence. In addition, the impact of linker dynamics and motif binding affinity, as well as the interplay between the two effects was studied. Our results support that fuzziness is a critical factor in driving higher-order protein organizations, and this could be used as a general framework to simulate different kinds of supramolecular assemblies.

Open Access: Yes

DOI: 10.1155/2018/6360846

Sustainability framework of recycled aggregate concrete produced with supplementary cementitious materials

T. Horváth David Bozsaky Mohammed Abed M. Shmlls

Publication Name: Ain Shams Engineering Journal

Publication Date: 2023-08-01

Volume: 14

Issue: 8

Page Range: Unknown

Description:

Engineering products’ sustainability has changed from being a choice to a crucial requirement. In this study, the impact of employing 20 % fly ash (FA) and/or 12 % silica fume (SF) as cement substitutes in the production of recycled aggregate concrete is examined. The examination was conducted in two stages, evaluation stage and analysis stage. In the evaluation stage, the mechanical characteristics, environmental impact, and production costs of ten concrete mixtures were assessed with laboratory experiments and data collection. While in the analysis stage, three multi-criteria decision-making techniques (namely: EDAS, VIKOR, and TOPSIS) were utilized to optimize the most valuable and sustainable concrete mixture. The key results displayed that utilizing up to 70 % of recycled concrete aggregate with an optimal dosage of a combination of 20 % FA and 12 % SF provides high-quality, environmentally friendly, and costly effective concrete.

Open Access: Yes

DOI: 10.1016/j.asej.2022.102036

Social problem-solving, coping strategies and communication among 5th and 7th graders

László Kasik Edit Tóth Anett Balogh-Pécsi

Publication Name: International Journal of Adolescence and Youth

Publication Date: 2024-01-01

Volume: 29

Issue: 1

Page Range: Unknown

Description:

The aim of the study is to explore the characteristics of social problem-solving, coping strategies and assertive communication among 5th- and 7th-grade students (N = 378). Communication is assessed with the Assertiveness Questionnaire (AQ, Gaumer Erickson et al., 2016), social problem-solving with the Social Problem-Solving Inventory–Revised (SPSI–R, D’Zurilla et al., 2002) and coping strategies with the Ways of Coping Questionnaire (WCQ, Lazarus & Folkman, 1988). The results show that mostly significant differences can be found between pre-adolescents and early adolescents in the three social fields. Low belief in problem-solving is more common among older students, and–besides the age difference–there are a number of areas where boys and girls differ, even among younger students. The SEM clearly identifies strong links between communication, coping strategies and problem solving. The results provide a more nuanced picture of boys’ social problem-solving, coping strategies and communication and the relation between them than before.

Open Access: Yes

DOI: 10.1080/02673843.2024.2331592

Psychological foundations of ambiguity in the hybrid workplace: The role of managerial risk-taking and AI-induced job insecurity

Mai Nguyen Bhumika Gupta Gábor Szábo-Szentgróti Rsha Alghafes Tuan Phong Nham Mai Nguyen

Publication Name: Acta Psychologica

Publication Date: 2026-02-01

Volume: 262

Issue: Unknown

Page Range: Unknown

Description:

In the modern ever-changing organizational environment, where hybrid workplace arrangement is becoming increasingly common, and artificial intelligence (AI) technology has been used widely, employees tend to face a situation characterized by ambiguity of work and it is difficult to perceive an understanding of role, expectations, and employment. The paper explores the interrelationship between task ambiguity, risk-taking by managers, AI-induced job insecurity, and employee outcomes in a hybrid working environment. This is based on Social Information Processing Theory where we advance a theoretical model that explores how workforce members actively learn and process information in their social context to get through ambiguity and foster resilience. The evidence of the proposed relationships is substantiated by three studies. Study 1 focuses on the way task ambiguity influences active lurking and also job engagement. Study 2 explores with the moderating factor on the relationship among the variables of task ambiguity, active lurking, and job engagement on managerial risk-taking. Study 3 examines how AI-induced job insecurity can moderate the link between task ambiguity and active lurking and job engagement. The results emphasize the need to ensure clear task specification, active lurking, management risk-taking and proactive efforts to reduce the issue of AI-induced job insecurity as factors that enhance employee engagement. The implications of the study are given and recommendations to conduct further research are outlined.

Open Access: Yes

DOI: 10.1016/j.actpsy.2025.106182

Relationship between knowledge sharing willingness and life goals of generation Z

Renata Machova Andrea Bencsik Tímea Juhász Peter Molnar

Publication Name: Proceedings of the European Conference on Knowledge Management Eckm

Publication Date: 2018-01-01

Volume: 1

Issue: Unknown

Page Range: 84-94

Description:

The most critical area of knowledge management systems is the knowledge transfer and knowledge sharing. Several research results have emerged applying different approaches with a focus why employees and leaders of companies do not share their knowledge. Differences in social, cultural and individual values are in the background of willingness to share knowledge. Each of these attributes raise further questions. The main objective of this research is to examine the knowledge sharing willingness of Generation Z and consider the cultural determinants having impact on them. The research objective was to compare the results of Hungary and Slovakia. A questionnaire survey was conducted among the students of elementary and high schools. The electronic questionnaire included questions on a 5-point Likert scale, which were evaluated with a help of simple and complex statistical methods using the SPSS program. The study of life goals was based on the study of Aspiration Index in earlier research. The results show that cultural characteristics have significant influence on the characteristic features of behaviour related to trust, learning and knowledge. The national culture has impact on knowledge-friendly attitude of the school community. According to Aspiration Index Analysis, intrinsic goals gain more importance than extrincic goals. While getting older, the importance on intrinsic goals is increasing. The highly materialistic approach (preference of extrinsic goals) reduces the ability to coopearate. It increases competition and the self-interest, which are obstacles to knowledge-sharing. The ratio of goals (intrinsic/extrinsic) determines the decisions of young people (career choice), as well as those important skills that are relevant in the society and influence career choice e.g. cooperation, responsibility.

Open Access: Yes

DOI: DOI not available

Modified bacterial memetic algorithm used for fuzzy rule base extraction

János Botzheim László Gál Laszlo T. Koczy

Publication Name: 5th International Conference on Soft Computing as Transdisciplinary Science and Technology Cstst 08 Proceedings

Publication Date: 2008-12-01

Volume: Unknown

Issue: Unknown

Page Range: 425-431

Description:

In this paper we discuss an improved version of the Bacterial Memetic Algorithm (BMA) used for fuzzy rule base extraction. In previous works we have found several ways to improve the original BMA. Some of them perform well rather in the case of more complex fuzzy rule base, and some of them perform well rather in the case of less complex fuzzy rule base. We have combined the improvements into a new version of the BMA that performs well in each case investigated. Copyright 2008 ACM.

Open Access: Yes

DOI: 10.1145/1456223.1456310

The r-switching-stable graphs

Jeanette C. McLeod Beáta Faller Brendan D. McKay

Publication Name: Discrete Applied Mathematics

Publication Date: 2019-08-15

Volume: 266

Issue: Unknown

Page Range: 16-29

Description:

Bondy and Mercier (2011) defined a switching at a vertex of a digraph to be the operation of reversing the directions of the edges incident with that vertex. They asked which digraphs have the property that every switching produces a digraph isomorphic to the original, which they called switching-stability. That version of the problem was solved for oriented graphs by the second author and Schweitzer (McKay and Schweitzer, 2014). In this paper we generalise the problem in several directions. As well as oriented graphs, we consider graphs with coloured vertices or edges, and various types of switching which apply to them. We further consider r-switching-stable graphs, which are those for which any r distinct switchings together produce a graph isomorphic to the original. Finally, we consider what happens if the isomorphism relation between graphs is weakened to isomorphism up to converse (reversal of all directed edges or changing of all colours). Our proofs employ a combination of group theory and combinatorics, with a small amount of computer assistance.

Open Access: Yes

DOI: 10.1016/j.dam.2018.12.013

Experimental Analysis of a Solar-Powered Centre Pivot Irrigation Site and Hyperlocal Evapotranspiration Data

Renato Kalocsai Nóra Gombköto Viktor Nagy Lajos Kubina Bálint Süle Viktor Nagy Zsolt Giczi

Publication Name: Chemical Engineering Transactions

Publication Date: 2024-01-01

Volume: 114

Issue: Unknown

Page Range: 787-792

Description:

In countries such as Hungary, the utilisation of solar energy for irrigation represents a pivotal consideration. As a consequence of climate change, the crop rotation period is characterised by an increased availability of sunny and bright days. A paucity of cloud cover and precipitation has distinguished recent Hungarian summers. The necessity for adaptation in agriculture, which produces raw materials for food, will also arise as a result of the increasingly extreme weather conditions caused by global climate change. The irrigation of crops is a vital process during increasingly frequent periods of drought. However, the cost of irrigation can be expected to rise significantly in response to elevated energy prices. The objective of this research is to ascertain the viability of utilising irrigation systems powered by renewable energy sources. Hungary is on the verge of a significant investment in its national irrigation infrastructure. Nevertheless, the investment may prove to be unprofitable as a result of the expense associated with the energy required for irrigation. In three research areas, the energy production of the solar farms associated with the pivot irrigation system has been monitored, and the hyper-local evapotranspiration data has been calculated. Regression analysis was employed to evaluate the results. The findings indicate that the dataset is significant. The field results and analysis can be useful for upfront investment in such projects. Precipitation, as a third variable, has a positive impact on the relationship between energy production and crop water demand.

Open Access: Yes

DOI: 10.3303/CET24114132