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Introduction to Design and Analysis of Torsional Vibration Dampers in Vehicle Industry
310-324Views:343The crankshaft of today’s internal combustion engines with high performance output are exposed to harmful torsional oscillations originated from the unbalanced gas and inertial forces. To avoid the fatigue damage of engine components, caused by the undesired vibrations, torsional vibration dampers can be applied. Viscodampers are one type of the torsional vibration dampers, which operational fluid is silicone oil. For cost-effective R&D activities and production, finite element and finite volume numerical discretization methods based calculation techniques must be involved into the engineering work supported by the modern computer technology. The aim of this paper is to provide an insight into the multidisciplinary design and development process of visco-dampers in vehicle industry applications. Four different examples as structural, fatigue, CFD analyses and structural optimization have been introduced in the present work. It turned out from the static structural and fatigue analyses, that the investigated damper has safety factor over the limit for both static structural and fatigue analyses, so it is suitable for the given load conditions. In the structural optimization process 34.36% mass reduction has been achieved. According to the coupled fluid dynamic and heat transfer simulations a rather stagnating air zone evolved between the engine and the damper during the operation, which can cause efficiency reduction of cooling fins mounted onto the housing. In light of the numerical results, the suitable damper position has been determined for the highest heat transfer.
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Transportation System of Major Cities in the Middle East
50-53Views:137The quality of transportation has a great effect on the quality of our everyday life and the future of our planet. In contrary to Europe, transportation culture of the big cities in the Middle East region has grown fully different way. These Middle Eastern cities tend to have a different historical, traditional and structural background compared to other cities all around the world. One of these big cities is in the focus of our paper: Rijad, with 6 million inhabitants is the archetypal car dominated city of the Arabic world. We also elaborated a comparison to 4 other cities: Dubai as a city similar to Rijad, Amsterdam as a city with a modern green attitude, Budapest as a metropolitan city in Hungary and last but not least Debrecen which is a Hungarian city with moderate population. As a lesson learnt, we try to give some possibilities and outlooks for Rijad, in order to improve the structure of transportation.
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The Factors of Digitality and Sustainable Competitiveness in the Domestic Context
217-226Views:184The recovery of international relations and the development of technology are in correlation with the increasing globalization tendencies. These processes increase the interdependence of countries, but also the competition between them. The factors of competition are constantly changing and being revalued. As a result new elements appear in addition to the traditional elements, and there are assimetries between existing components. The economic performance of a country increasingly depends on the knowledge and technology, its economic success on the use of knowledge. The purpose of the study is to present and analyze the proxies that define and shape the role of Hungary by IMD Competitiveness Research Center and by the complex indicators developed by Korea-based SolAbility. It also draws attention to all the factors that will significantly effect our country's economy in the future.
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An Analysis of the Leisure Preference System of Students with Disabilities in the Light of a Study
98-115Views:706With the increase in the number of disabled people and people with disabilities, research on the target group of people with disabilities has gained momentum in recent decades. Research is very diverse, looking at the labor market situation of people with disabilities, their leisure-time habits, or the factors that support and inhibit their sport.
In our questionnaire research, the leisure and sporting habits of children with disabilities aged 8-18 are described and analyzed (N = 639). Data were processed with spss software, where basic statistics and contextual analysis were performed. The results confirm that passive activities (TV, listening to music) dominate the leisure activities of children with disabilities. Sports consumption (active and passive) was more prevalent among male respondents and less prominent among girls. In the motivation of sports, besides improving the state of health, entertainment and company appeared.
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Examining the Virtues of Organisational Citizenship Behaviour (OCB) at an SME
41-52Views:186Nowadays, especially in the Eastern region of Hungary, small businesses face an increasing challenge in attracting and retaining a well-qualified workforce that is able to accept and commit to the goals of SMEs. This is due to the promising career prospects offered by foreign-owned large companies locating here. However, if SME employees possess the virtues of organisational citizenship behaviour (OCB), they will develop a stronger commitment to the organisation. The aim of our research was to explore the extent to which the five OCB virtues; sportsmanship, conscientiousness, altruism, politeness and civic virtue are present in a small construction company in Hajdú-Bihar county. Our survey was carried out using a questionnaire method, which was analysed as a function of length of service, education and age. The main findings are that there is a strong correlation between the presence of OCB characteristics and age and length of time spent with the firm.
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On the Hungarian Vocational Education System – opportunities in practical training
139-144Views:108The system of Vocational Education in Hungary is a rather complicated and the teaching staff and the students often do not know their way around it. In a new series of articles we intend to introduce the different parts of the national vocational training system. This is the first article of the series where we summarize the ways of practical training in the Hungarian Vocational Education System.
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Markmyprofessor: the More the Better?
232-243Views:1240Student evaluation of faculty members is a current topic both internationally and in Hungary, partly due to the massification and partly due to the marketization of higher education. One of the evaluation methods is the internet-based voluntary rating which was started by ratemyprofessors.com in the U.S.A. and whose Hungarian counterpart is markmyprofessor.com. Research studies on the U.S. website – among many other critics – established that reliability of this evaluation method highly depends on the frequency of ratings: if an individual tutor is evaluated by more students, then the standard deviation of the ratings is smaller. The previous conclusion about the U.S. website is tested in our study based on Hungarian data. Our main result is that many of the experiences about markmyprofessor.com echo the previous findings about ratemyprofessors.com. Beside this in the Hungarian sample the higher response rate is associated with lower average ratings.
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Analysis of the Situation and Structure of Passenger Transport in Hungary
195-208Views:140Traffic and transportation are important segments, as they contribute to the economy's functioning, to mobility, trade and job creation. Transport per capita spending in recent years exceeded 10% of the total spending of the population. In the first part of my article, I review the characteristics and importance of passenger transport. In the subsequent chapters, I will show how significant are the trends and differences that can be discovered when analysing population spending on transport, car purchases and maintenance and passenger transport by age group and educational attainment.
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The Role of Renewable Energy Sources in Energy Production and Use
678-688Views:330The role of renewable energies in energy management is growing both in the European Union and in Hungary. The use of renewable energy sources is already quite large (transport, heating, lighting, etc.) and it is advisable to deal with these energy sources in the year 2020. The use of energy from renewable sources can reduce greenhouse gas emissions and reduce dependency on the continuously problematic oil and gas market. A review of energy data over the last 10 years shows that renewable energy sources are playing an increasingly important role in the European Union. I support this finding by the fact that the share of energy from renewable sources in gross energy consumption has almost doubled in the last few years.
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Optimizing the combustion processes of a small scale solid fuel-fired boiler
358-369Views:144Over the last decade, the public has been paying increasing attention to reducing greenhouse gas and acid rain emissions and reducing particulate matter, which is extremely harmful to health and the environment. To improve air quality, the European Commission has achieved a range of measures to reduce air pollutant emissions in the transport, heat and electricity, industrial and agricultural sectors. In Hungary, the amount of gas and solid air pollutants from solid fuel combustion used by the public during the heating season represents a significant percentage of the total amount present in the atmosphere. In 2016, taking into the total emission, the 29% of CO2 emissions; 85% of CO emissions; 75% of the particulate matter emissions and 21% of the NOx emissions were derived from households. It follows that the improvement of air quality can also be achieved by controlling the emissions of solid fuel combustion plants. During our research we aimed to optimize the operation of a newly purchased TOTYA S18 boiler and a pilot pellet boiler. Operating the boilers in the correct mode minimizes air pollutant emissions, and the greater part of the heat generated is actually turns to heating the home, as with poor settings, a lot of heat leaves through the chimney. The data obtained during the tests can also be used to determine whether the boilers comply with the emission values set out in Commission Regulation (EU) 2015/1185.
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Laboratory Testing of Rediffusion of Contaminants Using DKS-Permeameter
41-48Views:145Decades long hydrocarbon contaminations effecting heterogenous groundwater systems is a common problem both in Hungary and worldwide. Only the treatment of aquifer layers is possible with remediation technologies, so the contaminations remained in the aquitards are released back to the treated porous layer after the treatment due to the changes in concentration-gradient. This process is the so-called back-diffusion: as a result, the previously removed contaminations appear in the remediated layer again. In order to get better understanding of the rediffusion process and the influencing parameters series of measurements were carried out at the University of Miskolc Faculty of Earth Science and Engineering using a special laboratory device called DKS-permeameter. With the help of some small modifications it can be used for the modeling of backdiffusion. Artificially contaminated soil samples were built in the DKS-permeameter from which contaminanant release occured due to back-diffusion. The concentration values were determined with spectrophotometric measurements.
