Претрага
2449 items
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Gate Road Support Deformation Forecasting Based on Multivariate Singular Spectrum Analysis and Fuzzy Time Series
Luka Crnogorac, Rade Tokalić, Zoran Gligorić, Aleksandar Milutinović, Suzana Lutovac, Aleksandar Ganić (2021)Underground mining engineers and planners in our country are faced with extremely difficult working conditions and a continuous shortage of money. Production disruptions are frequent and can sometimes last more than a week. During this time, gate road support is additionally exposed to rock stress and the result is its progressive deformation and the loss of functionality of gate roads. In such an environment, it is necessary to develop a low-cost methodology to maintain a gate road support system. ...deformacije podgrade, lasersko skeniranje, višekanalna singularna spektralna analiza, prognoza, klasterisanje fuzzy vremenskih serijaLuka Crnogorac, Rade Tokalić, Zoran Gligorić, Aleksandar Milutinović, Suzana Lutovac, Aleksandar Ganić. "Gate Road Support Deformation Forecasting Based on Multivariate Singular Spectrum Analysis and Fuzzy Time Series" in Energies, MDPI (2021). https://doi.org/https://doi.org/10.3390/en14123710
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Structural characterization of traditional pottery produced from local clay, Rujište (Ražanj, Central Serbia), in an effort to preserve its geoheritage
Maja Milošević, Biljana Đorđević, Alena Zdravković . "Structural characterization of traditional pottery produced from local clay, Rujište (Ražanj, Central Serbia), in an effort to preserve its geoheritage" in 9th International Conference Mineralogy and Museums, Sofia, Bulgaria, Earth and Man National Museum and Bulgarian Mineralogical Society (2021)
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The Fuzzy–AHP Synthesis Model for Energy Security Assessment of the Serbian Natural Gas Sector
Natural gas is used for the production of almost 20% of total energy today. The natural gas security of the Republic of Serbia is an urgent strategic, political and security issue. Serbia is one of the most vulnerable countries in Southeast Europe, because it only has one supply route. This study is a contribution to efforts to better understand the factors affecting energy security through the implementation of a new methodology based on the fuzzy–AHP synthesis model for measuring ...Aleksandar R. Madžarević, Dejan D. Ivezić, Miloš L. Tanasijević, Marija A. Živković. "The Fuzzy–AHP Synthesis Model for Energy Security Assessment of the Serbian Natural Gas Sector" in Symmetry, MDPI AG (2020). https://doi.org/10.3390/sym12060908
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Non-Detonating Chemical Mixture for Non-Invasive Methods of Rock Breaking
Within the Innovation developed several different non-detonating chemical mixtures for non-invasive methods of rock breaking. Laboratory and polygon tests gave the satisfactory results and knowledge enough to start the practical experiments in the field. The basis of this innovation is a theoretical assumption that certain chemical mixtures release a large quantity of gases during combustion. If these gases are found in the enclosed space a growing pressure on the walls of the chamber in which combustion takes place will ...Lazar Kričak, Milanka Negovanović, Nikola Simić, Stefan Milanović. "Non-Detonating Chemical Mixture for Non-Invasive Methods of Rock Breaking" in X International Scientific Congress Innovations 2024, Varna, Bulgaria, 24-27. jun 2024, Scientific Technical Union of Mechanical Engineering "Industry 4.0" (2024)
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The influence of alkyl polyglucosides (and highly ethoxylated alcohol boosters) on the phase behavior of a water/toluene/technical alkyl polyethoxylate microemulsion system
Marija Ilic, Franz-Hubert Haegel, Vesna Pavelkic, Dragan Zlatanovic, Snezana Nikolic-Mandic, Aleksandar Lolic, Zoran Nedic (2016)The influence of additives (alkyl polyglucoside, Glucopon 600 CS UP and alcohol ethoxylate C18E100) on the behavior of the water/toluene/Lutensol ON 50 (technical oxoalcohol, i-C10E5) microemulsion system as a function of temperature and composition has been investigated. The phase behavior of the microemulsions was determined by vertical sections through the Gibbs phase prism (fish-like phase diagrams). Alkyl polyglucoside shifts the one phase region to lower temperatures compared with water/toluene/Lutensol ON 50 mixtures. This is contrary to the expectation, considering ...микроемулзија, толуен, алкил полиглукозид, оксоалкохол етоксилат, појачивач ефикасности, „fish“ дијаграми... RESULTS AND DISCUSSION The pseudo-binary phase diagrams of micro- emulsion systems were determined at equal mass fractions of water and toluene (a= 0.5) for two non- ionic surfactants, pure linear CxjEs and technical branched i-Cxo5Es (Lutensol ON 50) in order to find the composition and temperature ...
... exists consisting of a middle-phase microemulsion in equilibrium with excess phases of oil and water, surrounded by two-phase regions illustrated as 20 and 20 . When a surfactant is mainly dissolved in water and two phases consist of a surfactant-rich water (lower) phase in equilibrium with an excess ...
... surfactant needed to solubilize water and oil and is a measure for the efficiency of the surfactant. The corresponding temperature, f, is a measure for the phase inversion temperature (//7). The phase diagrams were recorded by success- ively adding water and oil to the initial water-oil-surf- ...Marija Ilic, Franz-Hubert Haegel, Vesna Pavelkic, Dragan Zlatanovic, Snezana Nikolic-Mandic, Aleksandar Lolic, Zoran Nedic. "The influence of alkyl polyglucosides (and highly ethoxylated alcohol boosters) on the phase behavior of a water/toluene/technical alkyl polyethoxylate microemulsion system" in Chemical Industry and Chemical Engineering Quarterly, National Library of Serbia (2016). https://doi.org/ 10.2298/CICEQ141105015I
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The influence of alkyl polyglucosides (and highly ethoxylated alcohol boosters) on the phase behavior of a water/toluene/technical alkyl polyethoxylate microemulsion system
Marija Ilić, Franz-Hubert Haegel, Vesna Pavelkić, Dragan Zlatanović, Snežana Nikolić-Mandić, Aleksandar Lolić, Zoran Nedić (2016)The influence of additives (alkyl polyglucoside, Glucopon 600 CS UP and alcohol ethoxylate C18E100) on the behavior of the water/toluene/Lutensol ON 50 (technical oxoalcohol, i-C10E5) microemulsion system as a function of temperature and composition has been investigated. The phase behavior of the microemulsions was determined by vertical sections through the Gibbs phase prism (fish-like phase diagrams). Alkyl polyglucoside shifts the one phase region to lower temperatures compared with water/toluene/Lutensol ON 50 mixtures. This is contrary to the expectation, considering ...mikroemulzija, toluen, alkil poliglukozid oksoalkohol etoksilat, pojačivač efikasnosti, dijagrami “ribe”Marija Ilić, Franz-Hubert Haegel, Vesna Pavelkić, Dragan Zlatanović, Snežana Nikolić-Mandić, Aleksandar Lolić, Zoran Nedić. "The influence of alkyl polyglucosides (and highly ethoxylated alcohol boosters) on the phase behavior of a water/toluene/technical alkyl polyethoxylate microemulsion system" in Chemical Industry and Chemical Engineering Quarterly, National Library of Serbia (2016). https://doi.org/ 10.2298/CICEQ141105015I
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Determining the Availability of Continuous Systems at Open Pits Applying Fuzzy Logic
This work presents a model for determining the availability of continuous systems at open pits by applying fuzzy logic and fuzzy inference systems. The applied model was formed by the synthesis of independent partial indicators of availability. The model is based on an expert system for assessing the availability of continuous mining systems. The availability of the system, as a complex state parameter, is decomposed into the partial indicators, reliability, and convenience of maintenance, and the fuzzy compositions, used ...системи, континуални систем експоатације, површински коп, рударство, расположивост, фази логика, max–min композиција, min–max композицијаMiljan Gomilanović, Miloš Tanasijević, Saša Stepanović. "Determining the Availability of Continuous Systems at Open Pits Applying Fuzzy Logic" in Energies, MDPI AG (2022). https://doi.org/10.3390/en15186786
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Spatial distribution of major and trace elements in artificial lakes in Serbia: health risk indices and suitability of water for drinking and irrigation purposes
Goran Marković, Aleksandar Ž. Kostić, Nebojša Đ. Pantelić, Radojka Maletić, Jana Štrbački, Jovan Cakić, Lazar Kaluđerović, Biljana P. Dojčinović, Angelo Maria Giuffrè, Jelena B. Popović-Djordjević (2023)Lakes and reservoirs are the main water resources for household, irrigation, and industrial use. Hence, it is necessary to control water pollution and have reliable information on water quality, which refers to its suitability for a particular purpose. The main objective of this study was to evaluate the suitability of water for drinking and irrigation purposes from ten artificial lakes on the territory of the Republic of Serbia. The physicochemical parameters were determined using standard analytical methods, whereas the ...Goran Marković, Aleksandar Ž. Kostić, Nebojša Đ. Pantelić, Radojka Maletić, Jana Štrbački, Jovan Cakić, Lazar Kaluđerović, Biljana P. Dojčinović, Angelo Maria Giuffrè, Jelena B. Popović-Djordjević. "Spatial distribution of major and trace elements in artificial lakes in Serbia: health risk indices and suitability of water for drinking and irrigation purposes" in Environmental Monitoring and Assessment, Springer Science and Business Media LLC (2023). https://doi.org/10.1007/s10661-023-11740-6
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Mine ventilation system planning using genetic algorithms
The most common problem in contemporary mining practice related to the planning and analysis of ventilation systems is the optimization of partially regulated air distribution in mine ventilation networks. This paper presents a two step optimization procedure for partly regulated air distribution in mine ventilation networks. The first step is the determination of air distribution in all branches using the well known Hardy-Cross method. In the second step the distribution and parameters of air flow regulators with minimum engaged ...coal, lignite, and peat; ventilation systems; coal mining; underground mining; ventilation; mathematical models; design; air flow; optimization; calculation methods... using genetic algorithms N.M. Liliæ Faculty of Mining and Geology, University of Belgrade, Yugoslavia R.M. Stankoviæ Faculty of Mining and Geology, University of Belgrade, Yugoslavia I.M. Obradoviæ Faculty of Mining and Geology, University of Belgrade, Yugoslavia Abstract: ...
... engineering practice. The main features of the implemented method are discussed and illustrated by a case study. � 1 Introduction Adequate organization of mine ventilation systems and the achievement of safe and appropriate working conditions is regulated all over the world by legal acts covering ...
... (Cross 1936), and the second the use of genetic algorithms for determination of optimal distribution and parameter values for air flow regulators, providing at the same time the satisfaction of Kirhof's voltage law in the network (Liliæ & Kuzmanoviæ 1993). According to graph theory and Kirhof's laws ...Nikola Lilić, Ranka Stanković, Ivan Obradović. "Mine ventilation system planning using genetic algorithms" in 6. international symposium on mine planning and equipment selection, Ostrava (Czech Republic), 3-6 Sep 1997, A.A. Balkema, Rotterdam (Netherlands) (1997)
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Softverski alati za korišćenje resursa za srpski jezik
Ivan Obradović, Ranka Stanković (2008)Ivan Obradović, Ranka Stanković. "Softverski alati za korišćenje resursa za srpski jezik" in INFOteka: časopis za informatiku i bibliotekarstvo, Belgrade, Serbia : Zajednica biblioteka univerziteta u Srbiji (2008)
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Rift sequence stratigraphy and its contribution to source rock understanding – Serbian part of Pannonian Basin
Filip Anđelković, Dejan Radivojević (2018)Filip Anđelković, Dejan Radivojević. "Rift sequence stratigraphy and its contribution to source rock understanding – Serbian part of Pannonian Basin" in CBGA, Salzburg, Austria, Septembar 10-13, 2018, Bulgarian Academy of Science (2018)
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Creation of a Training Dataset for Question-Answering Models in Serbian
Razvoj i primena veštačke inteligencije u jezičkim tehnologijama značajno su napredovali poslednjih godina, posebno u domenu zadatka odgovaranja na pitanja (Question Answering - QA). Dok su postojeći resursi za QA zadatke razvijeni za glavne svetske jezike, srpski jezik je relativno zanemaren u ovoj oblasti. Ovaj rad predstavlja inicijativu za kreiranje obimnog i raznovrsnog skupa podataka za obučavanje modela za odgovaranje na pitanja na srpskom jeziku, koji će doprineti unapređenju jezičkih tehnologija za srpski jezik. Pored brojnih istraživanja o jezičkim modelima ...veštačka inteligencija, obrada prirodnog jezika, jezički resursi, anotirani skupovi, ekstrakcija informacija, odgovaranje na pitanjaRanka Stanković, Jovana Rađenović, Maja Ristić, Dragan Stankov. "Creation of a Training Dataset for Question-Answering Models in Serbian" in South Slavic Languages in the Digital Environment JuDig Book of Abstracts, University of Belgrade - Faculty of Philology, Serbia, November 21-23, 2024, University of Belgrade - Faculty of Philology (2024)
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Groundwater as an important resources in emergency situations of the Republic of Serbia
Boris Vakanjac, Radoje Banković, Vesna Ristić-Vakanjac, Saša Milanović, Ljiljana Vasić, Saša Bakrač, Nikola Kozić (2024)Groundwater is a renewable resource wholly or partially protected from external influences (pollutants) by nature. Currently, about 75% of the population of the Republic of Serbia meets its water needs by using underground water. Hence, this water represents an essential strategic resource of our country; according to data from the Water Management Foundation of the Republic of Serbia (VOS, 2001), water from existing sources is used in quantities of about 23 m3/s. As 67.13 m3/s is the estimated potential ...Boris Vakanjac, Radoje Banković, Vesna Ristić-Vakanjac, Saša Milanović, Ljiljana Vasić, Saša Bakrač, Nikola Kozić. "Groundwater as an important resources in emergency situations of the Republic of Serbia" in 11th International Scientific Conference on Defensive Technologies - OTEX 2024, Tara, October 2024, Military Technical Institute, Belgrade (2024). https://doi.org/10.5937/OTEH24122V
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Geologic Information System of Serbia
Geologic information system of Serbia (GeolISS) represents repository for digital archiving, query, retrieving, analysis and geologic data visualization. The GeolISS is implemented through ESRI ArcGIS technology, and is designed to operate as a personal geodatabase (MS Jet 4.0 Engine) and SDE enterprise geodatabase in MS SQL Server. The objective of GeolISS implementation is integration of existing geologic archives, data from published maps at different scales, newly acquired field data, as well as Web publishing of geologic information. Physical implementation ...Branislav Blagojević, Branislav Trivić, Ranka Stanković, Nenad Banjac, Olivera Kitanović. "Geologic Information System of Serbia" in Proceedings of the 17th Meeting of the Association of European Geological Societies, 14.-18. september 2011., Beograd : Srpsko geološko društvo (2011)
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Building Terminological Resources in an e-Learning Environment
Ranka Stanković, Ivan Obradović, Olivera Kitanović, Ljiljana Kolonja. "Building Terminological Resources in an e-Learning Environment" in Proceedings of the Third International Conference on e-Learning, eLearning-2012, September 2012, Belgrade, Serbia, Belgrade : Belgrade Metropolitan University (2012)
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Valorization of non-balanced coal reserves in Serbia for underground coal gasification
David Petrović, Lazar Kričak, Milanka Negovanović, Stefan Milanović, Jovan Marković, Nikola Simić, Ljubisav Stamenić (2019)In the name of a better and safer energy future, it is our responsibility to focus our knowledge and activities to save on imported liquid and gas fossil fuels, as well as coal on which energy security of Serbia is based. The rationalization in the use of available energy resources certainly positively affects economy and the environment of a country. This paper indicates motivations for the application of the underground coal gasification process, as well as surface gasification for ...... activated, and the coke burns the surrounding coal and forms the reaction zone. Exothermic reactions (at f > 600 "C) are predominantly occurring in UCG process, and the resulting gas mixture can contain 8-20% CO», 5-20% CO, 10-20% H», and 2-5% CHoa. Ifthe gas mixture contains too much CO., and possibly ...
... from the gas mixture of UCG, and its possible storage carbon capture and storage, depends on the technological development of the separation and storage of CO [3]. Syngas can be used to produce a number of usable products, such as electricity, liquid fuels and chemical raw materials. The com ...
... bar and — capacity up to 4000 mš of gas/h. And for the gas parameters are: — quantity of produced gas up to 100000 mž of gas/h, — gas pressure 0.2 bar, and — gas temperature 200-400 *C. Air, Oxygen, Steam CO,CO, H„ CH, |- —— Oxidation zone. —— j- Reduction zone +| -- Drying and Pyrolysis ...David Petrović, Lazar Kričak, Milanka Negovanović, Stefan Milanović, Jovan Marković, Nikola Simić, Ljubisav Stamenić. "Valorization of non-balanced coal reserves in Serbia for underground coal gasification" in Thermal Science (2019). https://doi.org/10.2298/TSCI190725390P
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Analysis and visualization of geophysical well-logging data from closely spaced boreholes
Geophysical logging measurements for determining the condition of the rock mass on the dam profile and locating the predisposed directions of water circulation and loss from the reservoir were conducted in four boreholes distributed at a close distance. The survey was carried out in a typical karst terrain, which is an additional challenge for defining the geological model, especially in terms of water retention. That kind of data set provides an excellent opportunity for a new approach to analysis ...... opportunity for a new approach to analysis and visualization that differs from the standard logging data processing. Numerical interpolation and correlation of data from various logging measurements (short-normal and long-normal resistivity, spontaneous potential and gamma ray logging), proved to be a ...
... s of karst in terms of surface and underground water circulation, as well as stability and hazard assessment for large objects such as dams (Sretković and Vučković, 2020). 'The use of geophysical characterization of karst systems can provide an economical and non-invasive alternative _ for ...
... for a new approach to analysis and visualization that differs from the standard logging data · processing. Numerical interpolation and correlation of data from various logging: measurements (short-normal and long-normal rresistivity, | spontaneous potential and gamma ray logging), proved to ...Branislav Sretković, Ivana Vasiljević, Dimitry Sidorov - Biryukov. "Analysis and visualization of geophysical well-logging data from closely spaced boreholes" in Vth Congress of the Geologists of the Republic of North Macedonia, Ohrid, Republic of North Macedonia, September 27-28, 2024, Macedonian Geological Society (2024)
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Data from the Digital Repository of the Faculty of Mining and Geology in eScience (eNauka)
Biljana Rujević, Mihailo Škorić (2024)The paper describes linking the Digital Repository of the University of Belgrade, Faculty of Mining and Geology, with the eScience system in terms of transferring metadata about the results of researchers' scientific work. The steps taken to ensure a smooth harvesting of metadata are outlined. Additionally, a presentation of additional improvements to the OAI system is provided, aiming to contribute to the automatic linking of authors with their results in the eScience system.Biljana Rujević, Mihailo Škorić. "Data from the Digital Repository of the Faculty of Mining and Geology in eScience (eNauka)" in Infotheca, Faculty of Philology, University of Belgrade (2024). https://doi.org/10.18485/infotheca.2023.23.2.4
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Analysis of the exhaust emissions inventory from auxiliary mining machines
Stevan Đenadić, Aleksandar Mirković, Jovana Mitrović, Filip Miletić, Predrag Jovančić, Dragan Ignjatović (2023)Open-pit coal mines are equipped with a large number of mining machines and vehicles with diesel engines. Due to common daily operation of these machines and vehicles large amounts of exhaust gases which contain numerous pollutants are emitted into the atmosphere. The demand to reduce air pollution induced the activities in developed countries to map and calculate all gases emitted by industries to formulate and select adequate preventive activities. In collaboration with machine manufacturers, emission standards for off-road machines ...Stevan Đenadić, Aleksandar Mirković, Jovana Mitrović, Filip Miletić, Predrag Jovančić, Dragan Ignjatović. "Analysis of the exhaust emissions inventory from auxiliary mining machines" in 9th International Conference Mining and Environmental Protection, University of Belgrade, Faculty of Mining and Geology (2023)
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Effectiveness Analysis of Different Bucket-wheel Excavators
Coal production in open-pit lignite mines in the Republic of Serbia is performed with continuous work systems. In addition to coal production, the same systems are used for the exploitation of large quantities of overburden. According to the reliability concept, continuous systems are in linear connection. If the failure occurs in one part of the system, that will produce a downtime of the entire system. The initial and most important factor of continuous systems is the bucket-wheel excavator. It ...... the equation (9) and (10) values of ideal (A+) and anti- ideal (A-) solution. By using equations (11) and (12) the distance of each alternative from the ideal solution (Si +, Si) is calculated. The values of (A+) and (A-) are presented in Table 8, and in Table 9 are values of (Si +) and (Si -). Table ...
... operation and maintenance of the oldest and newest bucket-wheel excavators in the Kolubara and Kostolac Mining Basin. Decomposition of working and maintenance parameters was performed on 4 sub- groups of parameters. Working parameters are average production, average operating time, time, and capacity ...
... thousand euros. The first and most important component of these systems is the bucket-wheel excavator (BWE). It is projected for twenty-four-hour work in all three work shifts with various working and climate conditions. Such circumstances require monitoring and analysis of working and maintenance parameters ...Stevan Đenadić, Predrag Jovančić, Dragan Ignjatović, Miloš Tanasijević, Filip Miletić. "Effectiveness Analysis of Different Bucket-wheel Excavators" in 8th International Conference Mining and Environmental Protection, Sokobanja, 22-25 September 2021, University of Belgrade, Faculty of Mining and Geology, Belgrade, Serbia (2021)