Претрага
4753 items
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Distribution of Uranium and Rare Elements in Radioactive Phosphate-Bearing Anomalies in Southeast Mongolia
Boris Vakanjac, Neil Rutherford, Vesna Ristić Vakanjac, Tanita Đumić, Suzana Đorđević Milošević (2020)Soviet and Mongolian geologists initiated geological exploration of Mongolia for minerals after World War II (1945). These activities lasted until the breakup of the USSR in 1991. As part of this exploration systematic uranium and rare element exploration was undertaken across Mongolia. New exploration resumed in Mongolia at the beginning of the 21st century for a range of ore and mineral deposit styles including uranium, coal, base and precious metals and Fe-ore. This was generally undertaken by Western-based companies. This ...Boris Vakanjac, Neil Rutherford, Vesna Ristić Vakanjac, Tanita Đumić, Suzana Đorđević Milošević. "Distribution of Uranium and Rare Elements in Radioactive Phosphate-Bearing Anomalies in Southeast Mongolia" in Minerals, MDPI AG (2020). https://doi.org/10.3390/min10040307
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Molecular and Isotope Composition of Biomarkers in Immature Oil Shale and its Liquid Pyrolysis Products (Open and Closed System)
Gordana Gajica, Aleksandra Šajnovic, Jan Schwarzbauer, Aleksandar Kostić, Branimir Jovančićević, Ksenija Stojanović (2021)The molecular and isotopic composition of biomarkers in initial bitumen isolated from raw immature oil shale samples from the Lower Miocene Aleksinac Basin (Serbia) and liquid products (LPs) obtained by pyrolysis in open (OS) and closed systems (CS) are studied. The influence of pyrolysis type and variations of kerogen type on biomarkers composition and their isotopic signatures in LPs is determined. The molecular composition of the LPs from the OS pyrolysis is very similar to those in initial bitumen, independently ...... and the Pr/Ph ratio is observed. Therefore, OS pyrolysis can be useful for assessment of source and depositional environment of OM. Pyrolysis in the CS caused more intense thermal stress; therefore the source fingerprints notably disappear. The obtained results indicate that n-alkan-2-ones and fatty ...Gordana Gajica, Aleksandra Šajnovic, Jan Schwarzbauer, Aleksandar Kostić, Branimir Jovančićević, Ksenija Stojanović. "Molecular and Isotope Composition of Biomarkers in Immature Oil Shale and its Liquid Pyrolysis Products (Open and Closed System)" in 30th International Meeting on Organic Geochemistry (IMOG 2021), European Association of Geoscientists & Engineers (2021). https://doi.org/10.3997/2214-4609.202134040
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Connections between the Levant and the Balkans in the late Middle Pleistocene: Archaeological findings from Velika and Mala Balanica Caves (Serbia)
Dušan Mihailović, Steven L. Kuhn, Katarina Bogićević, Vesna Dimitrijević, Ana B. Marín-Arroyo, Jelena Marković, Norbert Mercier, Bojana Mihailović, Mike W. Morley, Predrag Radović, William J. Rink, Senka Plavšić, Mirjana Roksandić (2022)Major changes in the technological, economic, and social behavior of Middle Pleistocene hominins occurred at the onset of the Middle Paleolithic, 400e200 ka. However, until recently it was not possible to establish when, where, and how certain forms of Middle Paleolithic behavior appeared and spread into Southeastern Europe, mainly owing to gaps in the Paleolithic record. Here we report new results of dating, material culture, and the archaeological context of finds from the Balanica Cave Complex in Sicevo (Serbia). ...Dušan Mihailović, Steven L. Kuhn, Katarina Bogićević, Vesna Dimitrijević, Ana B. Marín-Arroyo, Jelena Marković, Norbert Mercier, Bojana Mihailović, Mike W. Morley, Predrag Radović, William J. Rink, Senka Plavšić, Mirjana Roksandić . "Connections between the Levant and the Balkans in the late Middle Pleistocene: Archaeological findings from Velika and Mala Balanica Caves (Serbia)" in Journal of Human Evolution (2022)
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Ground surface subsidence monitoring using sentinel-1 in the “Kostolac” open pit coal mine
Zoran Gojković, Milan Kilibarda, Ljiljana Brajović, Miloš Marjanović, Aleksandar Milutinović, Aleksandar Ganić (2023)Open pit coal mining affects surrounding populated areas, resulting in terrain surface deformation. Surface deformation should be monitored as often as possible to control deformations and prevent potential incidents. This paper analyzes time series deformation estimated from the Sentinel-1 satellite images using the Persistent Scatterer Interferometry method to monitor subsidence rates caused by open pit mining activities. It is possible to measure deformations using classical geodetic methods, but those are rarely used in practice because they are time-consuming and ...Zoran Gojković, Milan Kilibarda, Ljiljana Brajović, Miloš Marjanović, Aleksandar Milutinović, Aleksandar Ganić. "Ground surface subsidence monitoring using sentinel-1 in the “Kostolac” open pit coal mine" in Remote Sensing (2023). https://doi.org/10.3390/rs15102519
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Industrial Waste Heat Potential for Meeting Heat Demand in the Republic of Serbia
Dejan Ivezić, Marija Živković (2023)Finalna potrošnja energije u industrijskom sektoru čini skoro 25% finalne potrošnje energije u Republici Srbiji. Procenjuje se da je 50-70% potrošnje energije u industriji namenjeno proizvodnji toplotne energije u različitim industrijskim procesima. Deo proizvedene toplotne energije se nepovratno gubi kao energija odvedena u okolinu: prenosom toplote kroz zidove procesne opreme, dimnim gasovim, otpadnim vodama itd. Korišćenjem otpadne toplote povećava se efikasnost korišćenja primarne energije i smanjuje ukupna potreba za energijom. Otpadna toplota se može koristiti u samom industrijskom objektu ...Dejan Ivezić, Marija Živković. "Industrial Waste Heat Potential for Meeting Heat Demand in the Republic of Serbia" in Energija, ekonomija, ekologija (2023). https://doi.org/10.46793/EEE23-1.17I
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Turbidity simulation for short-term prediction: case study of the karst spring Surdup (Bor, Serbia)
Из перспективе снабдевања пијаћом водом, квалитет воде карстних издани је међу највишим, и често захтева само њихову дезинфекцију пре употребе. Међутим, карстне подземне воде изложене су одређеним притисцима. Током сушних периода углавном има мало воде, а током кишних периода има изненадних променa и квалитета и количине воде. Реакција слива на падавине је често брза и варијације у параметрима квалитета и квантитета (истицање, ниво вода, замућеност, укупан број микроорганизама, суспендовани нанос, итд.) су нестабилни. Ово захтева праћење истицања и ...Marina Pešić, Vesna Ristić Vakanjac, Boris Vakanjac, Kostadin Jovanov. "Turbidity simulation for short-term prediction: case study of the karst spring Surdup (Bor, Serbia)" in Comptes rendus de l'Academie bulgare des Sciences, Bulgarian academy of science (2016)
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Production of electricity from coal-fired power plants and accompanying CO2 emissions: comparison of EU-27 and US
Even in the third decade of the 21st century, large power plants are still responsible for more than half of the electricity production in Europe and US. They predominantly use fossil fuels in their work, which results in the emission of pollutants into the air, soil and water. In addition to the production of electric energy, fossil fuels, including coal, are used for industrial purposes. Although the use of coal, especially in the countries of the European Union, is ...... j US average: 13061 kWh/c 12000 j 10000 j 8000 j EU-27 average: 6492 kWh/c 6000 4000 j 2000 j ——LFU-27 <——=US 0 eo w i e T T n o u 00 miuČ- O T W i m TO O ~ 0 O O a eNeon E:o:u: ' o e i e oč reeo oeezkžjjBNj“”oZo S Wwe e esA Č e!đ e RT NTe ı ...
... 1000 _ 500 _ Pa rt ic ip at io n of co al in el ec tr ic it y pr od uc ti on [% ] NE-U- .F T.E B SB- OB OB .BO""BS OB :Ba"0"| a aBšš e )0)00] 95 2855d45S E I I I 2R IR e a 88,868888B8B8aBaaBBSB BBB BSBaVBT.a s eee q a tc
... RRRR RSRRRRRRRSRSSSSSE Figure 1. Coal production in EU-27 and US At one time, coal had the greatest importance in the EU-27 countries as an energy source for obtaining electricity. In 1990, the share of coal in the production of electricity was 36,7%, while in 2021 this share was only 14,8% [4]. ...Uroš Djorgovski, Aleksandar Madžarević, Predrag Jovančić. "Production of electricity from coal-fired power plants and accompanying CO2 emissions: comparison of EU-27 and US" in International Conference on Global Energy and Climate Change - ICGRECC-23, New York, 2023, Research Galery- Science Leagues (2023)
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Development of Open Educational Resources (OER) for Natural Language Processing
In this paper we present the development of an online course at the edX BAEKTEL platform named “Lexical Recognition in the Natural Language Processing (NLP)”. It is based on the course of the same name for PhD studies at the University of Belgrade, Faculty of Philology. There are not many courses in Computational Linguistics (CL) on OER platforms, and there is none in Serbian either for CL or NLP. We have developed this course in order to improve this ...... UNITEX - OPEN ACCESS, OPEN SOURCE, OPEN EDUCATIONAL RESOURCES The course participant will become familiar with the use of Unitex, the corpus processing system for which many valuable resources for Serbian have already been developed. Unitex 11 is an open source system consisting of a collection ...
... development within BAEKTEL project of its OER version within the edX BAEKTEL platform. 2 The main features of Unitex, an open access and open source corpus processing system, are presented in Section 4. Section 5 presents course content with didactic criteria and specific formats used in the ...
... Lesser General Public License (LGPL). This means that everyone can redistribute Unitex freely within the terms of the LGPL license, access the source code of all Unitex modules and reuse it. 5. LEXICAL RECOGNITION IN NLP Course content The main topic of the presented course 12 is natural ...Cvetana Krstev, Biljana Lazić, Ranka Stanković, Giovanni Schiuma, Miladin Kotorčević. "Development of Open Educational Resources (OER) for Natural Language Processing" in The Sixth International Conference on e-Learning (eLearning-2015), September 2015, Belgrade, Serbia, Belgrade : Belgrade Metropolitan Univesity (2015)
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Overwiew of In-Pit Crushing & Conveying Technology in Open Pit Mines
The conditions under which contemporary surface mining operations is carried out obviously becoming increasingly complex. In such complex conditions, the optimization of haulage systems as the technological phase with the largest share in the total operating costs, is very important from the aspect of achieving profitability of the mining project. In a large number of cases, the application of traditional haulage systems with trucks (as the most dominant type of haulage in open pit mines) does not lead to ...Ali Nasirinezhad, Dejan Stevanović, Dragan Ignjatović, Petar Marković. "Overwiew of In-Pit Crushing & Conveying Technology in Open Pit Mines" in 8th International Conference MIining And Environmental Protection, Sokobanja, 22-25 September 2021, University of Belgrade, Faculty of Mining and Geology, Belgrade, Serbia (2021)
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Mikroelementi u kvartarnim sedimentima i lignitu Kostolačko-kovinskog ugljonosnog basena, istočna Srbija – odabrani primeri
Sadržaj, distribucija i način pojavljivanja elemenata u tragovima (mikroelemenata), posebno potencijalno toksičnih i radioaktivnih elemenata u uglju, su od velikog značaja, posebno ako se koriste kao gorivo u termoelektranama (TE). Na osnovu sistematski prikupljenih podataka o elementima u tragovima u uglju, zemljištu i sedimentima, moguće je utvrditi stepen zagađenosti vazduha, zemljišta, vode, kao i negativan uticaj na zdravlje ljudi. Eksploatacija i istraživanje lignita u Kostolcu i Kovinu traje više od jednog veka, dok se sagorevanje lignita sa površinskih kopa ...Bogoljub Vučković, Biljana Radovanović, Dragana Životić. "Mikroelementi u kvartarnim sedimentima i lignitu Kostolačko-kovinskog ugljonosnog basena, istočna Srbija – odabrani primeri" in 18. Kongres geologa Srbije "Geologija rešava probleme", Divčibare, 01-04 jun 2022., Srpsko geološko društvo (2022)
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Punctuated, episodic magmatism and mineralization of the Rogozna skarn-hosted Au-Zn-Pb-Cu deposits revealed through high-precision U-Pb zircon geochronology
The subvolcanic regions of magmatic centers are commonly associated with alteration, mineralization, and economic ore deposits, however the duration and frequency of mineralizing pulses within the overall lifespan of these centers can be poorly defined. Therefore, models for the formation of mineral systems require more highprecision geochronology data to refine their evolutionary models. Rogozna Mountain and its eponymous magmatic complex, located in SW Serbia, hosts multiple base metal deposits associated with variable rock types and structural expressions and serves as a natural laboratory to ...Skarnovska mineralizacija, Magmatsko-hidrothermalni sistemi, Subvulcanske intruzije, geohronologija na cirkonima, CA-ID-TIMSSean P. Gaynor, Milorad D. Antić, Vladica Cvetković, Kristina Šarić, Urs Schaltegger. "Punctuated, episodic magmatism and mineralization of the Rogozna skarn-hosted Au-Zn-Pb-Cu deposits revealed through high-precision U-Pb zircon geochronology" in Ore Geology Reviews, Elsevier (2023). https://doi.org/https://doi.org/10.1016/j.oregeorev.2023.105775
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SASA Dictionary as the Gold Standard for Good Dictionary Examples for Serbian
Ranka Stanković, Branislava Šandrih, Rada Stijović, Cvetana Krstev, Duško Vitas, Aleksandra Marković (2019)У овом раду представљамо модел за избор добрих примера за речник српског језика и развој иницијалних компоненти модела. Метода која се користи заснива се на детаљној анализи различитих лексичких и синтактичких карактеристика у корпусу састављених од примера из пет дигитализованих свезака речника САНУ. Почетни скуп функција био је инспирисан сличним приступом и за друге језике. Дистрибуција карактеристика примера из овог корпуса упоређује се са карактеристиком дистрибуције узорака реченица ексцерпираних из корпуса који садрже различите текстове. Анализа је показала да ...Српски, добри примери из речника, аутоматизација израде речника, издвајање својстава, Машинско учење... words No UCase inside sent. 5th 40th Median 65th 95th 28 64 73 87 150 0 0 0 0 0 5 10 12 14 25 3.6 4 4.8 5.2 6.6 0 3 4 5 10 0 0 0 0 2 Table 1: Data summary from SASA dictionary for selected features. 5. Preliminary model ...
... of 1, higher than 95th a score of 0, and between them linear interpolation is used. Besides the solution with multiple assessments of features, we have also used the analytic hierarchy process (AHP), where each feature value is converted to a numerical value from 0 to 100 and a numerical weight (priority) ...
... modernization could serve various different goals: speeding up the dictionary-making process, but also the development of a lexical database as the source for building new dictionaries of Serbian. 248 Proceedings of eLex 2019 In the e-lexicography era, with the imperatives of faster dicti ...Ranka Stanković, Branislava Šandrih, Rada Stijović, Cvetana Krstev, Duško Vitas, Aleksandra Marković. "SASA Dictionary as the Gold Standard for Good Dictionary Examples for Serbian" in Electronic lexicography in the 21st century. Proceedings of the eLex 2019 conference , Lexical Computing CZ, s.r.o. (2019)
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Regionalna karakterizacija karstnih podzemnih voda dela centralnog Balkana u funkciji njihovog održivog korišćenja i menadžmenta
Veljko J. Marinović (2022)Karstne podzemne vode koristi oko 700 miliona ljudi na svetu, čime je njihov značaj za svetsko stanovništvo nemerljiv. U sklopu doktorske disertacije vršena su istraživanja i analize karstnih sistema dela centralnog Balkana (Srbije, Crne Gore i Savskog sliva Bosne i Hercegovine), kako bi se evaluirao ovaj dragoceni resurs. Analize su vršene na primerima karstnih sistema vrela Perućac, Seljašnica, Mokra i Mlava (Srbija), Oko Bijele i Rijeka Crnojevića (Crna Gora) i vrelo Bosne (Bosna i Hercegovina), kao i na regionalnom ...karstni sistem, podzemna voda, pritisci na kvantitet i kvalitet, menadžment podzemnih vodnih resursaVeljko J. Marinović. Regionalna karakterizacija karstnih podzemnih voda dela centralnog Balkana u funkciji njihovog održivog korišćenja i menadžmenta, Beograd : [V. Marinović], 2022
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Application of the principle of circular economy to the thermal groundwater, the example of the municipality of Bogatić
There are about 360 locations of thermal and thermo-mineral waters in Serbia, whose water temperatures range from 14 to 98°C, which ranks Serbia as the richest European country in geothermal energy. The mentioned water resources (thermal and thermomineral waters) are used, mostly, for therapeutic purposes in spas and sports and recreational centers. The main problem that is present is the fact that they are not used in a rational and efficient way. The paper will give examples territorially related ...Marija Jovanović, Vesna Ristić Vakanjac. "Application of the principle of circular economy to the thermal groundwater, the example of the municipality of Bogatić" in Book of proceedings of the 3rd International Scientific Conference on vircular and bioeconomy CIBEK2021, Belgrade, Belgrade : School of Engineering Management (2021)
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Anthropogenic impact on the groundwater regime: Case study of the Velika Morava alluvium
Jovana Mladenović, Vesna Ristić Vakanjac, Milan Kresojević, Boris Vakanjac, Jugoslav Nikolić, Dušan Polomčić, Dragoljub Bajić (2023)The Velika Morava River originates at the junction of the Južna Morava and Zapadna Morava at the town of Stalać in Serbia. It is 185 km long and empties into the Danube. The Velika Morava River Basin occupies a land area of 37 444 km2. The river flows through central Serbia, which features the most fertile land and the highest population density in the country. Public water supply in this region of Serbia relies on groundwater formed in alluvial ...Jovana Mladenović, Vesna Ristić Vakanjac, Milan Kresojević, Boris Vakanjac, Jugoslav Nikolić, Dušan Polomčić, Dragoljub Bajić. "Anthropogenic impact on the groundwater regime: Case study of the Velika Morava alluvium" in National Conference with International Participation “GEOSCIENCES 2023”, Review of the Bulgarian Geological Society, Sofia : Bulgarian Geological Society (2023)
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Hydrodynamic analysis of radial collector well ageing at Belgrade well field
The origin and effect of hydraulic resistances on the rate of ageing of radial collector wells are identified through numerical hydrodynamic analysis. The research includes hydrodynamic modeling of one such well with new laterals at Belgrade well field. The performance of the laterals is aggravated by rapid ageing. The change in the hydraulic parameters of the laterals during the first decade of operation is analyzed through simulations of the groundwater regime with realistically specified geometries and hydraulics of the ...Đorđije Božović, Dušan Polomčić, Dragoljub Bajić, Jelena Ratković. "Hydrodynamic analysis of radial collector well ageing at Belgrade well field" in Journal of Hydrology, Elsevier BV (2019). https://doi.org/10.1016/j.jhydrol.2019.124463
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Fizičko-hemijsko raspadanje krečnjaka ugrađenih u objekte Beogradske tvrđave i mogućnost konsolidacije
Maja Z. Franković (2022)Beogradska tvrđava, spomenik kulture od izuzetnog značaja za Republiku Srbiju, izgrađena je od krečnjaka badenske starosti. Njihova litološka heterogenost, u sadejstvu sa uticajima okruženja, rezultira visokim intenzitetima raspadanja. Korelacijom intrinzičnih sa ekstrinzičnim faktorima, definisani su fizičko-hemijski procesi raspadanja ugrađenih mikrofacija krečnjaka. Aplikacijom neorganskih konsolidanata na karbonatnoj bazi (nano-kreča i Ca-acetoacetata) i alkoksisilana, te korelacijom fizičko-mehaničkih svojstava pre i nakon tretmana, ispitana je efektivnost u pogledu zaustavljanja dekohezije krečnjaka. Određivanjem petroloških, tehničkih svojstava i mapiranjem formi raspadanja Mračne kapije kao ...krečnjaci, forme i intenziteti degradacije, fizičko-hemijsko raspadanje, konsolidacija, nano-kreč, Ca-acetoacetat, alkoksisilani, Mračna kapijaMaja Z. Franković. Fizičko-hemijsko raspadanje krečnjaka ugrađenih u objekte Beogradske tvrđave i mogućnost konsolidacije, Beograd : M. Franković, 2022
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Prilog poznavanju režima i bilansa voda reke Resave
Sliv Resave zauzima područje između reke Velike Morave i obronaka Kučajsko-beljaničkih planina. Sliv i režim ove reke kontroliše se dvema hidrološkim stanicama: Manastir Manasija (slivno područje u iznosu od 388 km2) i Svilajnac (681 km2). Za potrebe analize režima voda reke Resave i uticaja padavina na formiranje oticaja sa njenog sliva preuzeti su podaci o padavinama sa meteorološke stanice Crni Vrh (1037 m nm) koji odslikava režim gornjeg dela sliva ove reke, i meteorološke stanice Smederevska ...Marina Mitrašinović, Vesna Ristić Vakanjac, Saša Milanović, Ljiljana Vasić, Dušan Polomčić. "Prilog poznavanju režima i bilansa voda reke Resave" in Zbornik radova XVI Srpski hidrogeološki simpozijum sa međunarodnim učešćem, Zlatibor, 2022., Univerzitet u Beogradu, Rudarsko-geološki fakultet (2022)
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Long-term planning methodology for improving wood biomass utilization
The insufficiently developed forest management system is often followed by undeveloped forest resources supply chain and insufficient institutional support. These cause inefficient usage of fuel-wood as well as huge amounts of unused forest residues. In order to achieve optimal and long-term sustainable utilisation of biomass, an original methodology based on the interaction of mathematical optimization and backcasting approach has been developed. Mathematical optimization is used for both generation and consideration of techno-economic parameters of the forest biomass supply chain. ...Vladimir Vukašinović, Dušan Gordić, Marija Živković, Davor Koncalović, Dubravka Živković. "Long-term planning methodology for improving wood biomass utilization" in Energy, Elsevier BV (2019). https://doi.org/10.1016/j.energy.2019.03.105
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Prioritization of strategic measures for strengthening the security of supply of the Serbian natural gas sector
To strengthen the security of supply of the Serbian gas sector, it is necessary to analyze the impact of planned strategic measures. The analysis involves the identification of the most influential threats to the security of natural gas supply and prioritization of the strategic measures for overcoming the consequences of threats. The proposed methodology is based on Fuzzy Analytic Hierarchy Process. The obtained weights for the identified threats and strategic measures are formed according to experts' judgments. The results ...Sigurnost snabdevanja, Donošenje odluka, Snabdevanje prirodnim gasom, Fazi AHP, Energetski indikatoriBoban Pavlović, Dejan Ivezić, Marija Živković. "Prioritization of strategic measures for strengthening the security of supply of the Serbian natural gas sector" in Energy Policy, Elsevier BV (2020). https://doi.org/10.1016/j.enpol.2020.111936