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This study aims to investigate the potential for biodiesel production from oilseed crops in Serbia, using a novel assessment method. The method involves calculating the arable land area that can be utilized for raw material production for the biodiesel industry. The available land for the production of biodiesel feedstocks is determined by subtracting the land required to meet the food needs of the domestic population and livestock from the maximum oilseed production area, which is defined as 20% of the total arable land area in Serbia. The findings reveal that approximately 353,000 hectares of land are available for producing raw materials for biodiesel production without compromising the domestic food supply. This land can provide enough raw materials to produce up to 324,000 tonnes of biodiesel annually, equivalent to 15.2% of the total domestic diesel fuel consumption for transportation in 2021. [ABSTRACT FROM AUTHOR]

The paper focuses on the area of experimental measurements for monitoring the impact of decarbonization on the technical and environmental parameters of the ICE. The condition for the implementation of the measurements was the selection of an ICE that had driven more than 300,790 km. During the laboratory tests, several test methods were used to assess the technical and emission conditions of the tested ICE with the code designation ALH, which is used in VOLKSWAGEN BORA vehicles. The technical parameters of the tested ICE (corrected power PNorm and torque MMom), emission parameters (absorption coefficient k and NOx emission) and fuel consumption parameters (specific fuel consumption bsfc) were compared and evaluated in the results. The results show that the decarbonization process on the tested vehicle VOLKSVWAGEN BORA 1.9 TDi affected the emission parameters but did not affect the technical parameters and specific fuel consumption. [ABSTRACT FROM AUTHOR]

To collect and unify data about all geothermal resources in Serbia, a database was formed. The database allows us to perceive the geothermal resources of Serbia and their potential for utilization. Based on the data available in the geothermal database, the estimated temperatures of reservoirs, heat power, and geothermal energy utilization were calculated. The database contains 293 geothermal records (springs, boreholes) registered at 160 locations, with groundwater temperatures in the range between 20 and 111 °C. The maximum expected temperature of the reservoir is 146 °C according to the use of a SiO2 geothermometer. Some thermal water is cooled due to mixing with cold, shallow water. Geothermal resources are mostly used for balneology and recreation, and less for heating, water supply, bottling, fish and animal farms, agriculture, and industrial. 26% of all geothermal resources is used by the local population or has not been used at all. The annual utilization of geothermal energy for direct heat is 1507 TJ/yr, and the estimated capacity of geothermal energy in Serbia is 111 MWt. The results of analytical work were presented in the form of maps with a geological and hydrogeological background. Thermal waters are mostly located within an area of Tertiary magmatism. Three geothermal potential areas are identified in Serbia: Pannonian basin-Vojvodina Province, the Mačva-Srem area and area from Jošanička Banja to Vranjska Banja (southern Serbia). Based on chemical analyses, four hydrochemical facies are distinguished. Thermal water mainly belongs to the NaHCO3 or CaMgHCO3 hydrochemical facies, usually depending on the primary aquifer type: karst, karst-fissured, intergranular or fissured. [ABSTRACT FROM AUTHOR]

Rapid growth in the energy consumption has conditioned the need for discovering the alternative energy resources which would be adapted to the existing engine constructions and which would satisfy the additional criteria related to the renewability, ecology, and reliability of use. Introduction of biodiesel has been the focus of attention over the last ten years. The aim of this research is to investigate the influence of biodiesel on the performances and exhaust gas emissions of medium power agricultural tractor engines (37-66 kW). The reason for the selection of this category is that those types of tractors are most frequently used in agriculture. In this research biodiesel produced from sunflower oil was blended with fossil diesel. Biodiesel, fossil diesel, and fossil diesel blends with 15, 25, 50, and 75%v/v biodiesel were tested for their influence on the engine performances and emissions. The testing was performed on a four-cylinder diesel engine with 48 kW rated power. The experimental research on the engine performances was conducted in compliance with OECD test CODE 2, and the exhaust gas emissions were tested according to the ISO 8178-4, C1. The use of biodiesel and fossil diesel blends reduced the engine power with the increase of biodiesel share in the blend. However, the exception was the blend with 15%v/v biodiesel which induced a slight increase in the engine power. Depending on the share of biodiesel in the blend all blends fuels showed increased specific fuel consumption compared to the fossil diesel. Thermal efficiency increased as a result of more complete combustion of biodiesel and fossil diesel blends. The exhaust gas emissions implied that the addition of biodiesel reduced the content of CO2 and CO, as well as the temperature of exhaust gases, but it increased the emission of NOx. [ABSTRACT FROM AUTHOR]

Power delivery efficiency shows how much engine power is used for a tractor drawbar. Eccentric traction is a factor influencing the power delivery efficiency of a wheeled tractor. It occurs as a consequence of the of set position of a tractor implement, that is, when the traction line of the tractor and resistance line of the implement are parallel and do not coincide. h is paper presents research on the power delivery efficiency of wheeled tractors and its dependence on wheel slippage of central and eccentric drawbar forces on unplowed and plowed stubble. For this purpose, mathematical models and one algorithm were developed. The best power delivery efficiency of the tractor on both unplowed and plowed stubble surfaces was obtained with central drawbar force. Power delivery efficiency of the tractor on unplowed stubble decreased by 5.72% if eccentricity increased up to 0.16 m and by 12.33% if eccentricity increased up to 0.32 m. Power delivery efficiency of the tractor on plowed stubble decreased by 8.88% if eccentricity increased up to 0.16 m and decreased by 19.05% if eccentricity increased up to 0.32 m. [ABSTRACT FROM AUTHOR]