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Temporal Changes of Pyrite Oxidation Rate in Bolivian Sulphidic Mining Wastes
194-202Views:232Since the 70's, when huge sulphidic open pits were developed, the acidic rock drainage (ARD) become the leader problem of the sulphidic mining industry. Although the recycling is an essential technology, it cannot cover the demand alone, thus mining activity needs to continue. Acidity in mine drainage commonly requires most of the attention, but the main problem is the caused elevated level of metal mobility and leaching, which are generated by the increased rates of sulphide weathering under acidic conditions. The Itos mine is a polymetallic vein deposit in Bolivia, had been mined for silver and tin until 1990, leaving behind much and huge tailings and mine waste heaps, where quite often the pyrite content exceeds 10 %. Serious ARD effects take place in the mine waste heaps. These processes can be well characterized with the pH 1 or 2 of the seepage water, which forms serious alteration in the waste itself and the neighbouring rocks. In three consecutive years, the pyrite oxidation rate was investigated on the same 7 samples by humidity cell test. 5-6 months pauses were left between the humidity cell test periods, which mimics the alternation of wet and dry periods, typical for the place. The results give much more information, than the oxidation rate in the individual test periods, showing the changes by time. This applied method gave good result to characterize the behaviour of the waste in long-term. The column test was complemented with mineralogical analyses, such as electron probe micro analysis. The mineralogical and column test analyses show, that the changes of the pyrite oxidation rate split the samples into three different groups, one where the oxidation rate decreases, second where it increases with time and the third where oxidation rate is maximal and stays stable for several years.
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Investigation of the Granulometric and Mechanical Properties of Inorganic Used Sand
302-308Views:306This paper examines the use of a modified inorganic binder in metal-alloy casting. The results of investigations regarding the effect of reusing the used sand multiple times without reclamation. The technological properties of silica sand with inorganic binders were presented, two different temperatures were applied to make the used sands. After lump crushing the inorganic used sand was recycled in order to make a new sand mixture. Our work was focused on the effect of multiple usage of inorganic used sands on the mechanical and granulometric properties prepared with modified inorganic binder.
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Testing of Micro Switches for Garden Tools
206-213Views:220The aim of this paper is to introduce the design of testing method for the prediction of the life and acceleration methods of the micro switches applied in different type of garden tools. These products will be tested for complex stressing, for example higher temperature, humidity, current load and so on. Therefore, the most important information and multi-factor acceleration models are summarized, the Weibull, the lognormal and the exponential distributions which are suitable for performing and evaluating tests.
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Effect of Heat Input on the Toughness Properties of S690QL Steel during Hardfacing
1-12Views:131In recent years, the use of high-strength steels in hardfacing process has become increasingly common. One typical industrial example is the case of hydraulic shears used in building demolition operations, where the components are exposed not only to significant abrasive wear but also to intense dynamic loading. The use of quenched and tempered high-strength steel grade S690QL has become particularly widespread in this field, primarily as the base material for the hardfacing applied to the most heavily loaded regions of demolition shears. However, quenched and tempered high-strength steels are highly sensitive to the effects of the welding thermal cycle, which typically cause detrimental changes in the microstructure and mechanical properties of the heat-affected zone. The thermal cycles occurring during hardfacing differ from those typical of fusion welding, and consequently, the structure and mechanical properties of the resulting heat-affected zone may also vary. In addition, the penetration depth of the hardface layer can differ, which may significantly alter the load-bearing cross-section of the high-strength steel and, thus, the in-service behavior of the component. In the experimental work, hardfaced samples were performed on S690QL base material using different levels of heat input, thereby producing varying penetration depths. The aim of the study was to determine the effect of penetration depth on the resistance of the hardfaced component to dynamic loading. The tests were carried out at both +20 °C and –40 °C. The results clearly demonstrated that samples with deeper penetration exhibited reduced toughness at both investigated temperatures.
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Application of Nanomaterials in Food Industry and Agriculture
116-126Views:353Nanomaterials have unique application features which can mainly be associated with their size properties. These materials have much higher surface than the normal particle size variant of the same materials. Due to these properties, nanomaterials are widely used in the industry. Food industry and the agrarian sector are using these materials increasingly. The main goal of nano size components and additives are the improvement of some parameters of the food manufacturing process, the elongation of the best before date of the food and the improvement of the texture, stability and the consistence of the food. Probably, nanomaterials will play an important role in the development of the food industry, moreover, it can be anticipated that nanotechnology will also appear there and will influence the whole food chain. It should be noted that food industry is using several nano size class materials which are not referred to as nanomaterials. Some examples are the micelles of some proteins, like milk protein, and fatty acids. Considering all these, the aim of our work was to present a thorough review and summary of the current applications.
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Application of Rexroth Controlling for Inverted Pendulum
174-179Views:325This paper deals with the control of an inverted pendulum. Balancing techniques are used in great many controlling problems. The inverted pendulum problem is often used as a benchmark. The theoretical background is well-known and easy to treat. A commercially available Rexroth axis controller and a CKK compact module are used to control the input of the system, which is usually applied in industrial fields. A test bench has been designed and built. A PLC based program has been developed to swing up the pendulum from the rest location to inverted position and LQR controller is designed to balance the system.
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Effect of the Changes in Bulk Density and Granulometric Properties on the Strength Properties of the Moulding Sand Mixtures
116-122Views:384Foundry technology uses a lot of several natural materials. Sands use for preparing mixtures whereby making moulds or cores. Sand is defined as a granular, refractory major portion of mixture (90 – 98% in dependence on used binder). Sand properties depend on it has chemical and mineralogical composition; mainly particle size distribution and shape of grains and its size and sand surface texture. A comparative measurement of two quartz sand with different surface quality was carried out. Greensand mixtures were prepared to measure their permeability, compressive strength and wet tensile strength. The strength of sand mixtures has two main components. One of them is the cohesion of the binder; the other one is the adhesion between the binder and the foundry sand. The aim of this research is to determine the ratio of cohesion and adhesion within the strength values.
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Investigation of Zeta Potential of Water Based Nanomagnetite-Bentonite Dispersions
54-66Views:335The stability of different type nanomaterials play an important role among recent scientific and industrial
challenges, including the examination of the effect of polymers, surfactants and their mixture on surface and electric surface properties and aggregation extent of dispersed particles, which are of utmost importance. Bentonite and its composite with different nanomaterials are frequently used for instance in environmental protection for wastewater treatment, since due to their great specific surface area they have excellent sorption properties. There are several publications in the literature for the application of bentonite in drilling muds. By using them the fluid loss can be decreased during the drilling process, the filtration of the fluid can be increased, it also improves the rheological properties and the formation damage can also be mitigated. During research the investigation and the analysis of the zeta-potential of nanoparticles and their composites at different pH and salt content can be an interesting topic. During our experiments the electric surface properties of nanomagnetite synthetized in laboratory (NM), cation
exchanged bentonite from Mád (Be) and the composite particles of these particles were investigated. Hybrid particles of different compositions (9:1, 7:3, 1:1, 3:7, 1:9) were analyzed at different potassium chloride concentrations (0.1 – 0.0001 M). The surface adsorption on the surface, i.e. the change in the surface charge can be traced well by analyzing the obtained zeta-potential values. The behavior of such systems was observed in the full pH interval, thus, valuable data were obtained regarding the colloidal stability. As for the stability, different requirements may emerge in practice, there are application fields where the colloidally stable system is advantageous, on the other hand, in some cases, ceasing the stabile system is the goal. Our investigations are of high importance in terms of stability and its characterization. -
Analysis of a Special, 3D Metal-Printed HPDC Tool Material
251-265Views:389High Pressure Die Casting (HPDC) is still the most productive metal-casting method of our time, however the more demanding are the industrial expectations, the more challenging it becomes to ensure the creation of the difficult cavity geometries and the thermal balance of the die-cast tool. New perspective is required, thus we can utilize high heat-conductivity tool steels and additive manufacturing technology.
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PVC/LDPE Blends: Relationship Between Thermal/Mechanical Properties, Structure and Blend Behaviour
162-165Views:349In this paper the effect of LDPE content in PVC foams are examined on the structure of both the foam and the LDPE. We attempt to understand how LDPE content affects the structure of PVC in blends and how it changes the glass-transition (Tg). These parameters often provide important information related to the overall macromolecular structure of the polymer blend. Thermal analytical techniques such as differential scanning calorimetry (DSC) often used to determine the structural transformation of samples. The effect of the miscibility and composition of the PVC/LDPE foam blends on the thermal stability were also investigated.
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The Challenges of the Labour Law and Economic in the Future Labour Market
116-130Views:1035The aim of the study is to examine how the effects of globalization affect the global labor market, and how high-level automation and digitalization affect the expectations of labor market actors and the world of labor law. We analyze the legal framework and the economic and social utility of acquiring competences for new challenges in the industry. We will look in more detail at the future of the low-skilled labor force in a changing labor market as a function of acquiring new competencies. We believe that changes in the labor market and novel processes will also pose new challenges for employers and employees. Changes in the labor market raise the question of what kind of benefits an outgoing worker will receive until he or she acquires new competencies. Is the social welfare system in the current sense capable of supporting lifelong learning, or is it necessary to explore alternatives such as basic income? All this needs to be done in the light of the legal and economic scrutiny of the concepts of efficiency and economy. This is because acquiring competences for the new employee also brings new added value.
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Maintenance from the Work Safety Point of View
190-196Views:290Deterioration of the technical condition of plant equipment is a common phenomenon nowadays. According to the experience of authorities, all this contributes to the occurrence of malfunctions and accidents. Plants that operate with an inadequate conservation strategy are now nearing the end of their design life, thus posing an increased accident risk. Aging processes are often accelerated by the operator's underestimation of the effects of equipment stress and the extent of deterioration mechanisms, and the consequent inadequate design and operation of condition monitoring and maintenance procedures. The aim of our work is to examine trends in the light of modern maintenance optimization methods and, in connection with this, to make proposals for the optimization of maintenance scheduling for employers.
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Potentiodynamic Study of the Effects of Nickel on The Electrodeposition of Zinc from Chloride Media
15-24Views:331Abstract. The potentiodynamic experiments of the nickel effects on the zinc electrodeposition have been done to understand the impact of Ni impurities on the electrowinning of Zn from spent pickling liquor. The nickel chloride solutions of Ni concentrations 90 and 1 g/dm3 were used as the electrolytes. The latter was also mixed with 90 g/dm3 Zn in the experiments. All the runs were carried out at room temperature with 40 mV/s continuous polarization speed and with 1/s sampling rate. It was observed that nickel electrodeposition from chloride media containing 90 g/dm3 Ni started with the generation of hydrogen bubbles, entirely blocking the cathode surface. Only a slight current development was observed until the polarization potential ~ -0,8 V. The visual observation showed bubbles also formed at the anode, which may represent chlorine and/or oxygen evolution. While, in the electrodeposition of nickel with only 1 g/dm3 Ni concentration in the electrolyte, metal deposition was hardly observed, but visible hydrogen bubbles constantly blocked the cathode surface. A similar tendency was observed in the mixed-solution electrolysis cell; the initial tiny bubbles accumulated at the cathode surface more than in the pure Zn solution. The enhancement of H2 evolution indicates how nickel deposition may contribute to the loss of useful current in the process of Zn electrodeposition. The mass of nickel deposited from the mixed solutions significantly decreases as the Ni concentration decreases in the electrolyte, while the mass of deposited zinc is relatively constant. It means that the purity of the produced Zn is appreciably higher – with respect to Ni – if nickel is efficiently eliminated from the solution before electrowinning.
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Effect of the Friction Coefficient on Clinch Joints
86-90Views:401In this study the effect of the friction coefficient on the clinch joints was examined in experimental and numerical way also. The knowledge of the frictional behaviour during the mechanical joining (i.e. clinching) is important from the point of view of resultant geometry which is related to and influence the strength of the joints, and furthermore the maximal forming force is limited by the tool’s failure load which can be reach with a non-favourable frictional condition, as well the aesthetic aspect are also has an importance in some special cases (e.g. in automotive industry).
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Learning Curve Based Sigma Level Determination in Interrupted Non-Production Processes
260-270Views:261The philosophy and methods of six sigma process development have been applied successfully since mid1980s, and the application of the six sigma concept in non-production processes has increased significantly in the last decade. In this paper processes that can be characterized by learning curves are modeled. The quality of such processes can be analyzed on the basis of the six sigma concept. In this paper two back office processes are analyzed. The processes are built up of simple repeated steps and incorporate some interruptions. The application of the model allows the calculation of the maximally permitted number of interruptions in the process if the preliminary determined norm is to be kept.
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Classification of Nanomaterial’s Risky Properties on the Aspect of Human Safety
34-45Views:352Due to their unique properties the application of nanomaterials continuously extends thus these appear for several industries. The industrial application of nanomaterials became significant during the last decades. As a result of the intensive development, our knowledge about the exact influence of nanomaterials for living bodies and human health is characterised by deficiency for both short and long time. Nanomaterials able to be entered to the living organism through several ways then invade to the circulatory system and the lymphatic system, reach the organs and can induce various kind of damages and serious diseases as a result of their different appearance, physical and chemical properties. Legislation in Hungary and in the European Union seems to be incomplete. There is no document which summarizes and details the risky factors and parameters in case of a risk assessment. Our aim was to develop a criterion system considering the risks related to the use and contact of nanomaterials based on their physical, chemical and biological properties, which criterion system could provide basic principle for a risk assessment thereby make the industrial processes safer both for the employees and those who are in the vicinity.
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Industrialization of knowledge in the University of Miskolc
61-73Views:352Life of universities has transformed thanks to “massification”. The costs of education have increased and universities had to manage a higher number of people. The economic management has moved towards business-like operation. The university has been transformed into an entrepreneurial university, while science has become knowledge production. The scientific policy has started to serve the needs of industrial corporations. The article titled (Industrialization of knowledge) introduces the research, developments, and innovations of the University of Miskolc. The university participate in national and international projects and they use the benefits of the research in developments. As the participants of innovations, they help in the introduction of new technical developments and the preparation of new products. Their operational experience is important for everybody.
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Design of Chip Conveyor
81-85Views:255The following article examines the design methodology of screw conveyors. The most significant steps are discussed concerning the design of the apparatus and its use in machine tools as a service component is explained.
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The Impact of Optical Character Recognition Artificial Intelligence on the Labour Market
9-16Views:567Because of present day information technology, there is neither need to plant complicated computers for more millions price if we would like to process and store big amounts of data, nor modelling them. The microprocessors and CPUs produced nowadays by that kind of technology and calculating capacity could not have been imagined 10 years before. We can store, process and display more and more data. In addition to this level of data processing capacity, programs and applications using machine learning are also gaining ground. During machine learning, biologically inspired simulations are performed by using artificial neural networks to able to solve any kind of problems that can be solved by computers. The development of information technology is causing rapid and radical changes in technology, which require not only the digital adaptation of users, but also the adaptation of certain employment policy and labour market solutions. Artificial intelligence can fundamentally question individual labour law relations: in addition to reducing the living workforce, it forces new employee competencies. This is also indicated by the Supiot report published in 1998, the basic assumption of which was that the social and economic regulatory model on which labour law is based is in crisis.
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Numerical analysis of effects of an open-pit coal mine to groundwater
70-74Views:333In this study we investigated the hydrogeological problems of an open-pit brown coal mine in the Borsod coal basin with Processing Modflow software. The coal mine is located in the valley of the Sajó-river with high transmissivity overburden layer where the traditional dewatering solutions were not encouraging due to inrush risks and low cost-efficiency. A new way of barrier forming was found out and numerically simulated to prove the efficiency of the solution. Since there are several contaminated sites in the surroundings it was a key factor to assure that the new mine dewatering technique has only a negligible effect on the groundwater regime that undisturbs the known contaminant plumes nearby.
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Determination of the Differential Equations of a Dynamical System using Dual Description
41-48Views:217The paper deals with the description of a mathematical model of a mechanical system using the so-called energy-based approach. The model is created using both generalized displacements and generalized momenta. The latter prescription method is less common in practice, due to its complexity. The two ways are presented through the same example mechanical problem, and a control task is also solved with the help of a PID block.
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Innovative Utilization Possibilities of Industrial Wastes from Hungary as Construction Industrial Material
203-212Views:261The research results carried out at the University of Miskolc Faculty of Earth Science and Engineering in the Center of Excellence of Sustainable Natural Resource Management show that the physical and mechanical properties of the construction industrial products (strength, compactness) made of waste sources can be controlled reasonably by the appropriate processing technologies and under optimized circumstances and characteristics (particle size distribution, specific surface area). It was established that beside the chemical activation, the mechanical activation of solids is an effective tool for improving the product characteristics. However, this modifies the physical as well as structural, mineralogical properties of the raw materials, therefore its determination is of great importance.
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Boundary Value Problem for a Heated Nanofluid Flow in the Presence of Magnetic Field
58-66Views:223The aim of this paper is to introduce some new numerical results on the magneto-thermomechanical interaction between heated viscous incompressible magnetic nanofluid and a cold wall in the presence of a spatially varying magnetic field. The governing nonlinear boundary layer equations are converted into coupled nonlinear ordinary differential equations by similarity transformation. The ODE system is solvable numerically for example using higher derivative method. The investigation is focused on the influence of governing parameters corresponding to various physical conditions. Numerical results are exhibited for the dimensionless wall skin friction and for heat transfer coefficients at the wall, along to distributions of the velocity and the temperature.
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Environmental Index and Environmental City Resilience Index calculation for Four Settlements in Szabolcs-Szatmár-Bereg County and Four in Győr-Moson-Sopron County
17-29Views:317Globalization and urbanization pose a number of challenges for different settlements. Stakeholders seek to cure global problems through sustainable projects. Since the Brundtland Commission's definition of sustainable development in 1987, the approach to sustainability has permeated all dimensions of the economy, including the environmental dimension. In Hungary, IBM conducted a study (Lados - Horváthné Barsi, 2011), in which the search for green, sustainable solutions defined in the definition of a livable city plays a key role. The characteristics of sustainable cities, that they are resilient to disasters, return to equilibrium after a shock has occurred (Seeliger, Turok, 2013). Resilience can also be mentioned as one of the pillars of sustainability. In a UN-Habitat statement, resilience refers to the ability of any urban system to withstand and recover from multiple shocks and to maintain the continuity of its services (OECD, 2018). In my study, I would like to present the results of the environmental index and the Environmental Urban Resilience Index (EURI) of the four largest cities selected on the basis of the population in the easternmost and westernmost counties of the country.
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Social Innovation for the Welfare of the Community
480-494Views:273The aim of the study is to highlight the focal points that are potentially activating factors in social innovation efforts in the most disadvantaged areas. The study examines certain social initiatives in the Nyírbátor district, with particular emphasis on the efforts promoting community welfare. The study primarily presents the results of qualitative interviews as part of a doctoral research. The examined cases play an important role in the management of the unfavourable processes in the region, and their adaptation as good practice can support the catching-up process. The study identifies the main groups of aspects that, in addition to structuring the case descriptions, also facilitate comparability of good practice. Documentation based on defined criteria supports the adaptation process, which is critical to the successful implementation of social innovation efforts.
