Theoretical and experimental studies on torque converters

Lysholm-Smith torques converters has a special importance, due to the fact that this kind of machine can realize a continuously variation of the torque and of the rotational speed to the outlet shaft as function of the resistant torqueand, in the same time, an amortization of the shocks and vibrations. This type of torque converter has three turbine stages, intercalated by two stages of reactors (having stationary blades). The present paper presents theoretical and experimental results obtained on a Lysholm-Smith torque converter CHC-380 in the laboratory of Hydraulic Machinery Departmentfrom POLITEHNICA University of Timişoara, ROMÂNIA. Theoretical, was studied the behavior of the torque converter, expressed by the characteristic curves. Experimentally, was studied the variation of the temperature inside the torque converter with and without the cooling system and, also, the influence of the filling degree on the characteristic curves. The paper discusses, in the same time the definition and the variation of the degree of transparency for this particular torque converter

Modelling of Spool Position Feedback Servovalves

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Finding the balance between the energy security and environmental protection in Serbia

There are very few issues that are as important to our collective future as energy. Like everyone else, Serbia has its stake in reducing energy price, enhancingthe security of energy supply, and reducing emissions, including greenhouse gas emissions associated with fossil fuels. In the years to come Serbian economy is expected to grow and industry to search and explore the potential of using cleaner alternative fuels. There is a lot that could be done to conserve energy and to reduce environmental footprint. But the most important thing that could be done to enable Serbian industry to reduce emissions is the implementation of a modernized power generation system. At the same time the reality can't be neither sugarcoated nor ignored and alternatives to fossil fuel will succeed only if they are economically feasible for suppliers and users alike. New technologies currently under development should be considered to allow Serbia the use of energy resources in a more efficient ways and with better protection of the environment. If successfully deployed, the development of alternative, renewable fuels will allow Serbian energy sector to effectively decouple its growth from green house gas emissions. This paper explore opportunities and the potential of alternative fuels for increasing competition inenergy supply, for reducing emissions and in Serbia while decreasing dependence on imported energy

Co-generation potentials of municipal solid waste landfills in Serbia

Waste management in Serbia is based on landfilling. As a result of many years of practice, a large number of municipal waste landfills has been created where landfill gas has been generated. Landfill gas, which is essentially methane (50- 55%), and CO2 (40-45%) (both green-house gases), have a great environmental impact which can be reduced by using landfill gas in cogeneration plants to produce energy. The aim of this paper is to determine economic and environmental benefits from such energy production. For that purpose, the database of cogeneration potentials of 51 landfills in Serbia was created. Amount of landfill gas generated at each municipal landfill was calculated by applying a first order decay equation which requires the data about solid waste production and composition and about some landfill characteristics. For all landfills, which have over 100,000 m3 each, a techno-economic analysis about building a combined heat and power plant was conducted. The results have shown, that the total investment in 14 combined heat and power plants with payback period of less than 7 years amounts 11,721,288 €. The total nominal power of these plants is 7 MW of electrical power and 7.9 MW of thermal power, and an average payback period is about 61 months. In addition, using landfill biogas as energy source in proposed plants would reduce methane emission for 161,000 tons of CO2 equivalent per year

Analysis of the electricity production potential in the case of retrofit of steam turbines in a district heating company

Today, in Serbia there are several sites with installed combined heat and power facilities. The most of these plants, for various reasons, do not produce electricity. One such plant is Energetika (Kragujevac, Serbia), which is primarily a district heating company. Steam generator in the plant has been installed in the 1970's and has worked in one short period of time. Installed steam turbines are 8 MW and 20 MW rated power. Energetika in accordance with the general trend of increasing energy efficiency of production process initiated revitalization of the plant. This revitalization started with a study which approach and the results are briefly given in the paper. All results show that retrofit of facility should be acceptable for the management. Developed scenarios indicate that in the case of the limited resources optimal retrofit should start with smaller turbine (8 MW rated power) then after providing the funds should continue with the retrofit of 20 MW turbine

An overview of the regulatory framework for the geothermal energy in europe and Serbia

In this paper the relevant legislation for the geothermal energy in the European countries and Serbia is reviewed. There is a variety of the incentives for the geothermal production which are well known throughout the European Union. The governmental policies for the support of the geothermal development have so far focused on the power generation only. It is necessary to make serious efforts in order to harmonize the legislation and to simplify the procedures of establishing and implementing the policies for boosting the direct use of the geothermal energy. The Law on Energy of the Republic of Serbia which was adopted by the Parliament and the Energy Development Strategy of the Republic of Serbia until 2015 have defined the privileged power producers, but only by passing the Regulation on the incentive measures for the production of electricity using the renewable energy sources combined with the production of electricity and the thermal energy, which came into force on January 1 st 2010

Experimental and artificial neural network approach for forecasting of traffic air pollution in urban areas: The case of subotica

In the recent years, artificial neural networks have been used to predict the concentrations of various gaseous pollutants in ambient air, mainly to forecast mean daily particle concentrations. The data on traffic air pollution, irrespective of whether they are obtained by measuring or modeling, represent an important starting point for planning effective measures to improve air quality in urban areas. The aim of this study was to develop a mathematical model for predicting daily concentrations of air pollution caused by the traffic in urban areas. For the model development, experimental data have been collected for 10 months, covering all four seasons. The data about hourly concentration levels of suspended particles with aerodynamic diameter less than 10 μm (PM10) and meteorological data (temperature, air humidity, speed and direction of wind), measured at the measuring station in the town of Subotica from June 2008 to March 2009, served as the basis for developing an artificial neural networks based model for forecasting mean daily concentrations of PM10

Assessment of plastic flows and stocks in Serbia using material flow analysis

Material flow analysis was used to assess the amounts of plastic materials flows and stocks that are annually produced, consumed, imported, exported, collected, recycled, and disposed in the landfills in Serbia. The analysis revealed that approximately 269,000 tons of plastic materials are directly disposed in uncontrolled landfills in Serbia without any pretreatment, and that significant amounts of these materials have already accumulated in the landfills. The substantial amounts of land-filled plastics represent not only a loss of valuable recourses, but also pose a serious treat to the environment and human health, and if the trend of direct plastic land-filling is continued, Serbia will face with grave consequences

Determination analysis of temperature regimes, functional characteristics and sliding curves of a hydrodynamic clutch

Analysis of output quality of power transmitters is possible in position when characteristics are determined earlier. This is the reason why we focused on determination of these characteristics for a concrete power hydro-transmitter. This means that the investigation task primarily consisted of determination of functional characteristics, defining of the sliding curves and temperature regimes of a concrete hydrodynamic clutch. Results of velocity and pressure field investigations in the working space of this clutch, obtained by use of the same test setup, are the basis for determination and analysis of the functional characteristics, sliding curves and temperature regimes. In this work we also analyzed function of the hydrodynamic transmitter in assembly with an internal combustion engine, as well as a process of acceleration and deceleration of a vehicle with this assembly in it

The connection between Arctic Oscillation (AO) and the forest fires in Manitoba Province (Canada)

A downward trend of the annual number of forest fires and upward trends of the annual burned area and the average burned area per fire were recorded in Manitoba in the period 1970-2014. Pearson’s correlation coefficient (R) was used in the research of the connection between Arctic oscillation (AO) and forest fires. The values of R significant at p≤0.01 were recorded for the annual burned area and summer AO (0.425) and July AO (0.402), as well as for the average burned area per fire and summer AO (0.445)