Vol. 3 No. 1 (2018)

Published February 13, 2018

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Materials Sciences

  • The Effect of Sizes of the Cast Polyamide 6 Rods upon Tensile-Impact Strength
    21-24
    Views:
    113

    We have studied the tensile-impact strength of the magnesium catalysed cast polyamide 6 (PA6) rods according to the EN ISO 8256:2004 standard. The purpose of our investigation was to follow: the mechanical properties of rods are mapped beside same casting technological process in case of different diameters. We have compared the received results with each other than have sought disparities. We examined cylindrical product (rod) in seven dimensional steps in diameter ranging from 40 mm to 300 mm. We have determined that the semi-finished products can be divided into two groups typically in case of their tensile-impact strengths in this size range. The tensile-impact strength is higher in case of the rods with a diameter of less than 100 mm and it is smaller in the larger dimension range. Therefore, the smallest tensile-impact strength can be established in case of the natural semifinished PA6 rods that each rod accomplishes independently of size. However, a range can be determined, which the tensile-impact strength values of product are separated according to the manufacturing size

    98
  • New Method for Dynamic Tribological Test of Engineering Polymers
    25-29
    Views:
    106

    In this article, tribological tests of Polyamide 6 (PA 6), Ultra High Molecular Weight Polyethylene (UHMW PE) and Polyoxymethylene copolymer (POM C) by a new testing method is introduced. The tribometer used in the test is capable for pin-on-disc measuring within all possible layout known in tribology practice, otherwise can be modified into special model of fatigue sliding test. The pin was a specimen made from examined materials, always in contact with a rotating metal disc under a normal load, which is usually static. However, since vibration exists in every practical scene as an important phenomenon, for instance in turning process, we added vibration load into the test. The supplement load is generated by a special-designed vibrating machine. Then properties of examined materials can be studied more profoundly under vibration load. As a result, different value of friction coefficient in static and vibration load have been discovered and taken into comparison.

    79

Economics

  • The Relationship Between Renewable Energy Consumption, Net Energy Import, Greenhouse Gas Emission and Human Cap
    58-71
    Views:
    139

    The measures to improve energy efficiency and increase of renewable energy production and consumption should be encouraged in the interest of sustainable development. Many factors can influence the use of renewable energy such as the level of economic development of an economy, nationals’ and the main  economic actors’ environmental awareness, energy import dependency, ratio of the urban population, and government subsidization intensity among the others. The main purpose of this study is to examine the relationship between the share of renewable energy in the total energy consumption and net energy import as a percentage of energy use less production, greenhouse gas emission per capita and human capital using by OECD countries data from 1990 to 2014. The results indicate that there is a negative relationship between net energy import and renewable energy consumption, and also negative relationship can be shown between the amount of greenhouse gas emission per capita and renewable energy consumption. However, we identified a positive relationship between human capital and renewable energy consumption for energy importer countries above a certain level of human capital.

    hu
    139
  • Outlook of Precision Farming in Hungary
    133-147
    Views:
    1092

    For agriculture, precision farming means the future by increasing incomes and reducing environmental loads at the same time Precision management produces a surplus in yield, revenue, result, but not immediately. The additional income potential is expected to increase by 20% to 50%. Farms mostly introduce precision farming in order to relieve workers. However, many farmers are afraid of the use of new technologies, but the use of information technology in agriculture will be unavoidable. Technology is fundamentally expensive, not even widespread, and farmers use only a few technology elements. Moreover, following the precautionary principle technology used in farming covers only a part of their agricultural land. So farms need to learn to produce more precisely than before in a knowledge-based manner.

    hu
    1785

Mechanical Engineering

  • Defect Analysis of Bearings with Vibration Monitoring and Optical Methods
    1-12
    Views:
    138

    Diagnosis of bearings with advanced methods gained remarkable roles in the previous years. This article focuses on the manufacturing defects and methods to reveal and classify them. During manufacturing several faults could emerge because of the grinding operation, tool wear and chatter vibration. Inproper handling of the bearing parts because of the collosion to each other and the storing box that causes deformation. To reveal these problems several methods are applied in industry. For deeper surface analysis nitric acid can be used to initate the finished surface of the roller then natrium-carbonate that nautralize the elements. Vibration analysis in its standard Fourier form is not a new achivement but other mathematical tools could be applied to condition monitoring such as wavelet transform. It is an efficient tool for analyzing the vibration signal of the bearings because it can detect the sudden changes and transient impulses in the signal caused by faults on the bearing elements. In this article five different wavelets, Daubechies, Gaussian, Coiflet, Mexican hat, Meyer are compared according to the Energy to Shannon Entropy ratio criteria to reveal their efficiency for fault detection.

    125
  • Finite Element Software for Rubber Products Design
    13-20
    Views:
    251

    Automotive rubber products are subjected to large deformations during working conditions, they often contact with other parts and they show highly nonlinear material behavior. Using finite element software for complex analysis of rubber parts can be a good way, although it has to contain special modules. Different types of rubber materials require the curve fitting possibility and the wide range choice of the material models. It is also important to be able to describe the viscoelastic property and the hysteresis. The remeshing possibility can be a useful tool for large deformation and the working circumstances require the contact and self contact ability as well. This article compares some types of the finite element software available on the market based on the above mentioned features.

    1004
  • Experimental and Numerical Investigation of Clinched Joints
    80-86
    Views:
    87

    In this study DP600 type of steel sheets were examined by experimental and numerical simulations. The clinch joint is can be created between thin sheets with a punching tool and a die during plastic deformation. The punching tool is deforming the sheets with a given force. The process is kind of a press forming joining technique which makes the joints defines by the tools. During the process the sheets are plastically deformed and the specific “S” shaped undercut is formed. This shape is one of the most essential geometrical parameter of the joints.

    hu
    173
  • Maintenance Strategies and Life Cycle Costs of Renewable Energy Systems
    106-116
    Views:
    109

    Life cycle costs are important factors in decisions on renewable energy investments. Since maintenance costs generally constitute a high portion of the life cycle costs, the maintenance strategy applied in a project can affect the bottom line significantly. The effective maintenance tools used in the production industry (e.g., diagnostics, condition monitoring, data management, integrated information systems, machine learning, and automated decision making) can be involved in planning and maintenance of renewable energy systems to gain the benefits of these approaches. In this paper the effects of maintenance strategies on life cycle costs are investigated and the benefits of up-to-date condition monitoring techniques are presented through case studies.

    hu
    101

Environmental Engineering

  • Laboratory Testing of Rediffusion of Contaminants Using DKS-Permeameter
    41-48
    Views:
    114

    Decades 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.

    hu
    57
  • R&D infield of “Waste-to-Energy”in Institute of Raw Materials Preparation and Environmental Processing, University of Miskolc
    49-57
    Views:
    100

    The importance of research and development in the field of „Waste-to-Energy” is vital in our modern society trying to establish the circular economy. Such R&D activity has been carrying out at Institute of Raw Materials Preparation and Environmental Processing for decades in several directions. This paper deals with the main results of research on refuse derived fuel from MSW, biogas production, briquetting of biomass, as well as production of fluid fuels.

    hu
    292
  • The Comparative Analysis of the Microbial Communities of Activated Sludge
    87-101
    Views:
    131

    The composition of the microbial communities in the activated sludge was thought mostly chaotic and unpredictable, but due to the new studies and breakthroughs in the past decades, now it is known that specific, accidental and non-accidental factors are responsible for the structure of the microbial community. The aim of the study is to compare the microbial communities of activated sludge of one large and two small wastewater treatment plants. During our research 14 months of data were processed. After the sample analysis and data processing, the diversity and seasonal changes of the community structures revealed. The results of the statistical analysis show that the larger system has more diverse community structure.

    hu
    195
  • Determination of the Accumulation of the Heavy Metal Content of the Sediment of River Danube by Plants
    163-170
    Views:
    92

    In these days, the surface waters and their floodplains and oxbow lakes are operating as ecological corridors, although their touristic role is not negligible. The monitoring and saving of these wetlands need for sustain these areas for the future generations. The environmental parameters of floodplains and oxbow lakes is revealed with the analyses of the quality of the water and sediment. The main sampling place of our research is a sediment dump was created by excavation from the Open Beach of Dunaújváros in 2009. In 2010 the whole sediment dump was planted with trees, and many kinds of weeds were also grown here. The main aim of this research is to analyse the heavy metal content of the sediment dump in Dunaújváros. Furthermore, the heavy metal content of the parella (Rumex obtusifolius L.), perennial rye-grass (Lolium perenne) and riparian sedges (Carex riparia) which are growing on the sediment dump were also analysed. The distribution and the accumulation of the heavy metals inside this plant can be also determined with these measurements.

    hu
    149

Management Sciences

  • The Importance of Energy Management in Hungary
    72-79
    Views:
    102

    One of the important elements of our everyday life is energy, but the amount of it is constantly decreasing, so it is advisable to include renewable energies in our energy management in addition to traditional energy sources. In the field of energy management, the use of renewable energies deserves attention because their share is increasing, although their percent is small. At present, Hungary and the European Union's energy policy contain guidelines that aim to increase the utilization of renewable energy sources. These directives contribute to achieving environmental and climate protection goals, job creation, territorial and urban development, and the reduction of dependence on energy imports. In my article, I would like to present various calculations in the field of energy management as a result of the previously described information and I would like to explore the energy management contexts that have come to the fore when examining residential energy consumption

    hu
    72
  • Practice of Organizational Development in a Domestic Company
    117-126
    Views:
    919

    In today's changing world, it is extremely important that organizations can keep up with market trends. The perspectives of continuous development are expanding and the commitment of decision-makers to development activities is growing steadily. The starting point for organizational development is always man. Organizational development always begins with deeper research and modeling. Fundamental guidelines are set out as a paradigm of development. The most important and at the same time the most difficult step is to introduce the results of the analysis. The most effective, but the most time-consuming and cost-effective solution is full organizational development. The management of the organization faces significant efforts to embark on a full organizational development process. The aim of our study is to propose different development opportunities for the company's management with the help of analysis by the organization and supported by measurable data, as well as the catalyst for the modifying efforts observed among employees.

    hu
    2336
  • Impression Management Strategies Used by Foreign Students
    127-132
    Views:
    91

    In this paper, we examined a general human behaviour, the impression management among university students. People are interested in how others think about them. At the organizational level, they can also benefit from being positively judged by others. Effort to create this positive image is Impression Management, which has several measurement options. In this paper, we conducted research on the impressions strategies used by first year international students of University of Debrecen, Faculty of Economics and Business Administration, Bachelor in Business Administration and Management programme. In our analysis we used the questionnaire consisting of 22 questions developed by Bolino and Turnley. We analysed what strategies are typical for the examined student group and to what extent? Are there differences in the strategies employed by men and women and depending on their cultural background.

    hu
    76
  • Process Innovation Tools and Strategies in Production Management
    148-162
    Views:
    285

    The method of process innovation helps to recognize the opportunities in production processes that represent clear competitive advantage. Using it, up to 30% change is available in increasing productivity and in the reducing of costs, stocks, and lead times. There is no need for complicated methods in the process development. The power of logical, simple tools relies on the fact that everyone can learn, understand, apply them and give quick feedback about their operation. Significant changes have been made in today's possibilities of designing and operating production systems. The emergence of cyber physical systems, the opportunities offered by big data, and the "Internet of Things" (Internet of Things) have shown strong research potential for more efficient logistics and manufacturing systems. The potential of network co-operation, information gathered from tracing materials in production and communication between machines provide a wide-range of optimization opportunities for manufacturing processes. The toolkit presented in the research cannot only be used in direct production; almost all parts of the value creation process can be broken down into routine actions, so the causes of the problems can be analyzed and the development of the process’ parts can be easier implemented.

    hu
    185

Mathematics, Physics, Informatics

  • Tools to Develop End-User Programming Skills from Primary School to Higher Education
    30-40
    Views:
    97

    Some years ago at the MIDK2013 Conference [16] we presented a concept regarding the use of a new generation of computer programming novice languages (in fact, an environment, called ‘block languages’). We showed how we imagine the use of this kind of language for different ages and at different levels of education. Now we would like to present the results of our projects related to this concept and our psychological and pedagogical experiences. Furthermore we would like to present further tools to develop end-user programming skills from primary school to higher education.

    98
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