Претрага
1232 items
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Double traveling valve increases rod-pump efficiency
Traditional sucker rod pumps (SRP) use a single traveling valve, but recent double traveling valve innovations have improved SRP performance and efficiency in field applications with double traveling valves installed in pumps with top mechanical seating. The valves sealed better and produced similar fluid volumes compared with the previous single-valve pumps. They also enabled a reduction in pump diameter and optimized usage of surface equipment. Overall, the double travel valve SRPs produced stable production rates and annual production targets.Miloš Petrović, Bojan Martinović, Milica Ješić, Miroslav Crnogorac. "Double traveling valve increases rod-pump efficiency" in Oil & Gas Journal (2023)
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Одређивање оптималних параметара рада бушотина у повременом гаслифту
Радослава Јованчевић (2024)Гаслифт представља механичку методу производње при коме се производна бушотина снабдева гасом под високим притиском, а његова притисна енергија се користи како би се подржао еруптивни рад бушотине или након еруптивног рада, у циљу истискивања заосталог флуида. Два основна типа гаслифта су повремени и континуални гаслифт. У овом раду је детаљније описана метода повременог гаслифт система. Одређивање оптималне количине гаса који се утискује и расподела ограничене количине гаса на групу бушотина представља битан део пројектовања сваког гаслифт система. Главни ...Радослава Јованчевић. Одређивање оптималних параметара рада бушотина у повременом гаслифту, 2024
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A Correlation Relating the Residual Strength Parameters to the Proportions of Clay Fractions and Plasticity Characteristics of Overburden Sediments from the Open-Pit Mine Drmno
Jedan od preduslova za bezbedno obavljanje eksploatacije na površinskim kopovima, jeste stabilnost završnih i radnih kosina kopa. Da bi se ovo obezbedilo potrebno je izvršiti detaljna terenska i laboratorijska geomehanička ispitivanja tla i na osnovu dobijenih rezultata uraditi proračune vezane za analize stabilnosti. Ovako dobijeni rezultati koriste se za dimenzionisanje nagiba eksplotacionih kosina (iskopa), odnosno kosina formiranih usled odlaganja jalovine. Klizišta nastaju kada je dostignuta granična čvrstoća smicanja i zato je adekvatno definisanje parametara čvrstoće na smicanje, jedan ...Stevan Ćorluka, Dragoslav Rakić, Nikola Živanović, Ksenija Đoković, Tina Đurić. "A Correlation Relating the Residual Strength Parameters to the Proportions of Clay Fractions and Plasticity Characteristics of Overburden Sediments from the Open-Pit Mine Drmno" in Applied Sciences, MDPI AG (2024). https://doi.org/10.3390/app142210325
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Prilog poznavanju promena kvalitativnih parametara voda vrela banje kod Valjeva
Jovana Lončar, Maša Vulović, Veljko Marinović, Branislav Petrović, Radisav Golubović, Vesna Ristić Vakanjac (2024)Zbog nepristupačnosti karstnih masiva i nenaseljenosti slivova karstnih vrela, često se sprovode osmatranja parametara kvaliteta i kvantiteta voda sporadično, po potrebi i to godišnje, sezonski/kvartalno, mesečno, nedeljno. Analize ovako formiranih nizova mogu dovesti do pogrešnih zaključaka, naročito kada se vrše analize ekstrema. Međutim, kada su u pitanju karstne izdanske vode, režim pojedinih parametara može biti jako uslovljen pluviografskim režimom. Najčešći su slučajevi da nakon otapanja snežnog pokrivača, zatim pri kišama jačih intenziteta ili dužih trajanja dolazi do skoro istovremenog ...Jovana Lončar, Maša Vulović, Veljko Marinović, Branislav Petrović, Radisav Golubović, Vesna Ristić Vakanjac. "Prilog poznavanju promena kvalitativnih parametara voda vrela banje kod Valjeva" in Zbornik radova XVII srpskog simpozijuma o hidrogeologiji sa međunarodnim učešćem, Beograd : Univerzitet u Beogradu - Rudarsko-geološki fakultet (2024). https://doi.org/https://doi.org/10.5281/zenodo.13740037
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Uticaj zemljišta i epikarsta na kvalitet podzemnih voda karstne izdani na primeru karstne izdani Suve planine
Kroz zemljište migriraju i cirkulišu različite supstance u obliku pravih i koloidnih rastvora, a u njemu se odvija i mnoštvo hemijskih reakcija. Kao rezultat kretanja supstanci i biološke aktivnosti organizama u zemljištu se formiraju slojevi određenih fizičko-hemijskih i bioloških osobina. Na taj način u zemljištu se odvija prvi korak u promeni sastava infiltrirane površinske vode i njen postepen prelaz u podzemnu vodu.Rastvaranje krečnjaka je već u površinskim delovima krečnjaka – epikarstu veoma intenzivno, što podaci prikupljeni sa lokacije pećine Peč, ...Branislav Petrović, Živojin Smiljković, Veljko Marinović. "Uticaj zemljišta i epikarsta na kvalitet podzemnih voda karstne izdani na primeru karstne izdani Suve planine" in Zbornik radova XVII srpskog simpozijuma o hidrogeologiji sa međunarodnim učešćem, Beograd : Univerzitet u Beogradu - Rudarsko-geološki fakultet (2024). https://doi.org/https://doi.org/10.5281/zenodo.13739367
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Recent advances made by reaction experiments on melting of heavily metasomatized hydrous mantle
Dejan Prelević, Michael W. Förster, Stephan Buhre, Fatma Gülmez, Tobias Grützner, Yu Wang, Stephen F. Foley (2024)Mantle-derived magmas are traditionally assumed to originate by melting of an upper mantle consisting of uniform spinel- or garnet peridotite dominated by olivine. However, extensive studies of mantle-derived basalts suggest that the mantle is more mineralogically heterogeneous, so that the genesis of even the most common magmas requires consideration of mixed source regions within the mantle involving pyroxenites and hydrous minerals. We refer to these with the group term metasomes. However, most experimental studies on mantle melting have assumed ...Dejan Prelević, Michael W. Förster, Stephan Buhre, Fatma Gülmez, Tobias Grützner, Yu Wang, Stephen F. Foley. "Recent advances made by reaction experiments on melting of heavily metasomatized hydrous mantle" in Earth-Science Reviews (2024)
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Analiza primene višekriterijumskih metoda u optimizaciji izbora hidruličnih bagera na površinskim kopovima uglja
Hidraulični bageri primenjuju se u različitim oblastima privrede a najzastupljeniji su u građevinarstvu i rudarstvu. Na površinskim kopovima sa kontinualnim sistemima, klasifikuju kao pomoćna mehanizacija a na površinskim kopovima sa diskontinualnim sistemima, kao osnovna mehanizacija. Kako je u oba slučaja njihova primena neizostavna, važno je izvršiti adekvatnu analizu postojećih podataka, u cilju optimizacije izbora tipa hidrauličnog bagera u odnosu na uslove rada datog površinskog kopa. U radu su opisane različite višekriterijumske metode koje su korišćene za analizu hidrauličnih bagera. ...Stevan Đenadić, Predrag Jovančić, Dragan Ignjatović, Filip Miletić, Ivan Janković. "Analiza primene višekriterijumskih metoda u optimizaciji izbora hidruličnih bagera na površinskim kopovima uglja" in Tehnika, Centre for Evaluation in Education and Science (CEON/CEES) (2019). https://doi.org/10.5937/tehnika1903369D
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The lost freshwater goby fish fauna (Teleostei, Gobiidae) from the early Miocene of Klinci (Serbia)
Freshwater gobies played an important role in the Miocene paleolakes of central and southeastern Europe. Much data have been gathered from isolated otoliths, but articulated skeletons are relatively rare. Here, we review a rich assemblage of articulated gobies with abundant otoliths in situ from the late early Miocene lake deposits of Klinci in the Valjevo freshwater lake of the Valjevo-Mionica Basin of Serbia. The fauna was originally described by Anđelković in 1978, who noted many different fishes, including one ...Katarina Bradić-Milinović, Harald Ahnelt, Ljupko Rundić, Werner Schwarzhans. "The lost freshwater goby fish fauna (Teleostei, Gobiidae) from the early Miocene of Klinci (Serbia)" in Swiss Journal of Palaeontology, Springer Science and Business Media LLC (2019). https://doi.org/10.1007/s13358-019-00194-4
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Uporedni prikaz proizvodnje električne energije iz uglja zemalja Evrope sa najvećim udelom: politika i projekcija proizvodnje
Energetski razvoj zemalja Evrope decenijama je bio baziran na uglju. Instalisana snaga svih energetskih kapaciteta koji su zasnovani na uglju je preko 2000 GW. Ugalj je i dalje od bitnog značaja za dobijanje električne energije u Evropi. I pored toga što postoji veliki potencijal uglja, trend je smanjenja proizvodnje električne energije iz uglja do 2050. godine. Imajući u vidu Zelenu agendu i politiku EU, zemlje Evrope se okreću obnovljivim izvorima energije. Srbija u okviru obnovljvih izvora ima potencijala prevashodno ...Predrag Jovančić, Dragan Ignjatović, Stevan Đenadić. "Uporedni prikaz proizvodnje električne energije iz uglja zemalja Evrope sa najvećim udelom: politika i projekcija proizvodnje" in Energija, ekonomija, ekologija, Savez energetičara (2022). https://doi.org/10.46793/EEE22-3.63J
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Structure, interaction with biomolecules, and cytotoxicity of copper (II) complexes chelating some Schiff base ligands
Aleksandar Mijatović, Angelina Z. Caković, Aleksandar Lolić, Olivera Klisurić, Marko N. Živanović, Dragana S. Šeklić, Snežana Sretenović, Marija Ilić, Jovana Bogojeski (2023)Cancer remains one of the world's deadliest diseases, claiming many lives each day. Transition metal complexes are leading candidates in developing anticancer agens with cisplatin used in chemotherapy worldwide. Copper, an endogenous metal in the human body, is especially attractive because of its typical redox biological activities and a relatively strong affinity to nucleobases. A series of Cu(II) complexes with ethane-1,2-diamine as the amine part and pentane-2,4-dione and/or 1-phenylbutane-1,3-dione, pentane-2,4-dione and/or 1,1,1- trifluoropentane-2,4-dione, or 1,1,1-trifluoropentane-2,4-dione and/or 1-phenylbutane-1,3-dione as the ...Aleksandar Mijatović, Angelina Z. Caković, Aleksandar Lolić, Olivera Klisurić, Marko N. Živanović, Dragana S. Šeklić, Snežana Sretenović, Marija Ilić, Jovana Bogojeski. "Structure, interaction with biomolecules, and cytotoxicity of copper (II) complexes chelating some Schiff base ligands" in Applied Organometallic Chemistry, Wiley (2023). https://doi.org/10.1002/aoc.7253
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Projected changes in air temperature, precipitation and aridity in Serbia in the 21st century
Boško Milovanović, Sebastian Schubert, Milan Radovanović, Vesna Ristić Vakanjac, Christoph Schneider (2021)In this study, the projected changes of the average monthly and annual air temperatures, precipitation amounts and De Martonne aridity index in Serbia in the 21st century are examined. For that purpose, the spatial distribution of air temperature and precipitation amount is statistically modelled using data of 64 climatologic stations and 421 precipitation stations for the period 1976–2005 using multiple linear regression. The De Martonne aridity index is calculated from the spatially distributed data. In order to obtain regional ...Boško Milovanović, Sebastian Schubert, Milan Radovanović, Vesna Ristić Vakanjac, Christoph Schneider. "Projected changes in air temperature, precipitation and aridity in Serbia in the 21st century" in International Journal of Climatology (2021). https://doi.org/10.1002/joc.7348
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Развој геолошког информационог система Републике Србије
Геолошки информациони систем Србије (ГеолИСС) је пројектован, првенствено, са намером ефикасног дигиталног архивирања геолошких и њима сродних података. У овом раду је приказана структура базе података као основа за развој геолошки конципираног ГИС-а. Нови, објектно орјентисани (О-О) начин моделирања омогућио је дефинисање самосталних типова објеката, хијерархијски повезаних кроз тополошке и друге релације, чиме је обезбеђена њихова медјусобна интеракција. Објектно оријентисано моделирање извршено је коришћењем унифицираног језика моделирања (UML) и CASE алата, кроз концептуални и логички ниво. Физички модел ће ...Бранислав Благојевић, Бранислав Тривић, Ненад Бањац, Ранка Станковић, Велизар Николић. "Развој геолошког информационог система Републике Србије" in 14. конгрес геолога Србије и Црне Горе са међународним учешћем, Нови Сад, 18-20. октобар 2005, Cpпско геолошко друштво и Caвeз геолошких друштава Србије и Црне Горе (2005)
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Adaptive neuro-fuzzy prediction of operation of the bucket wheel drive based on wear of cutting elements
The capacity of the rotor excavator depends largely on the operation of the subsystem for digging. There is a great contribution to the correct and sharp teeth when the capacity is the highest. In the function of time, the teeth become clogged due to abrasive wear, or changes in their geometric shape. To analyze the bucket wheel drive in depend on wear of the cutting elements in this study adaptive neuro fuzzy inference system (ANFIS) approach was implemented. ANFIS ...Filip Miletić, Predrag D. Jovančić, Milos Milovančević, Dragan Ignjatović. "Adaptive neuro-fuzzy prediction of operation of the bucket wheel drive based on wear of cutting elements" in Advances in Engineering Software, Elsevier BV (2020). https://doi.org/10.1016/j.advengsoft.2020.102824
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Application of the Fuzzy Model in the Evaluation and Selection of Hydraulic Excavators on Open-Pit Lignite Mine
Stevan Đenadić, Miloš Tanasijević, Vladimir Milisavljević, Dragan Ignjatović, Predrag Jovančić (2021)The production of lignite in large open-pit mines is mainly performed with continuously operating equipment, where bucket-wheel excavators, bucket-chain excavators, belt conveyors, and spreaders are the basic machines. Smaller machines, usually of discontinuous operating nature, are commonly categorized as auxiliary machines. This paper presents the research related to the analysis of auxiliary machine parameters with the case study for a hydraulic excavator. The purpose of the analysis was to develop a model of rating quality of service of the ...Stevan Đenadić, Miloš Tanasijević, Vladimir Milisavljević, Dragan Ignjatović, Predrag Jovančić. "Application of the Fuzzy Model in the Evaluation and Selection of Hydraulic Excavators on Open-Pit Lignite Mine" in SSRN Electronic Journal, Elsevier BV (2021). https://doi.org/10.2139/ssrn.3945617
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Резултати иницијалних хидрогеолошких истраживања карстног врела Бијели Нерини (централна Црна Гора)
Врeлo ’’Биjeли Нeрини’’ (305 мнв) нaлaзи нa сjeвeрoзaпaдним oбрoнцимa планине Мaгaник, изнaд кoритa риjeкe Мртвицe (на њеној десној обали). Извoриштe je рaзбиjeнoг типa, кoje je зaтрпaнo крупним блoкoвимa крeчњaкa и дoлoмитa. Извoриштe je вeoмa издaшнo, сa прeтпoстaвкoм дa у минимуму имa приближно 500 л/с, дoк му мaксимум прeлaзи и прeкo 2000 л/с, aли збoг кoнфигурaциje тeрeнa je зa сaдa билo вeoмa тeшкo пoтврдити тe вeличинe. Прeдстaвљa сeгмeнт који упoтпуњуje цjeлoкупну слику геолошких и физичкo-гeoгрaфских спeцифичнoсти кaњoнa риjeкe Мртвицe, десне ...Голуб Ћулафић, Вељко Мариновић, Јелена Крстајић, Бранислав Петровић. "Резултати иницијалних хидрогеолошких истраживања карстног врела Бијели Нерини (централна Црна Гора)" in Записници Српског геолошког друштва (за 2021. годину), Српско геолошко друштво (2022)
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Numerical Modeling and Simulation of the Effectiveness of Groundwater Source Protection Management Plans: Riverbank Filtration Case Study in Serbia
The paper describes the establishment and testing of an algorithm for developing sustainable management plans associated with groundwater source protection against potential pollutants and discusses the effectiveness of individual systems. The applied methodology pertains to groundwater resource management, particularly those cases that involve riverbank filtration. Namely, groundwater (numerical) modeling is employed to examine the groundwater regime and balance, as well as to create protection systems and illustrate their effectiveness. Particle tracking analysis is used to study pollutants’ travel and ...Dušan Polomčić, Dragoljub Bajić, Bojan Hajdin, Dragan Pamučar. "Numerical Modeling and Simulation of the Effectiveness of Groundwater Source Protection Management Plans: Riverbank Filtration Case Study in Serbia" in Water, MDPI AG (2022). https://doi.org/10.3390/w14131993
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Status and tendencies under development and application of underground coal gasification-UCG
Podzemna gasifikacija uglja u Svetu poslednjih decenija doživljava znatnu ekspanziju u istraživanju i razvoju zbog uveliko iskorišćenih ležišta uglja i loših ekoloških efekata (pri sagorevanju u TE) na životnu okolinu. Srbija ima znatne rezerve uglja, a kada bi se za PGU koristile samo vanbilansne rezerve i otkopni ostaci bilansnih, jasno je kakvi bi bili ekonomski (a i energetski i ekološki) efekti. U radu su sagledane aktivnosti u Svetu na tom planu, pa smatramo da ima smisla i potrebe za primenu ove ...David Petrović, Lazar Kričak, Stefan Milanović, Jovan Marković, Nikola Simić. "Status and tendencies under development and application of underground coal gasification-UCG" in International Conference “Energy and Ecology Industry EEI2018”, Beograd : Akademija inženjerskih nauka Srbije (AINS) (2018)
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Karst wastewater as a high quality, renewable and within the circular economy water resource
Jovana Nikolić, Vesna Ristić Vakanjac (2021)High quality drinking water in it’s natural state is becoming less and less available to the human population. Based on the expected climate changes, it is considered that this resource will be less in the world but also in our region. Also, the accompanying polluting components that exceed the maximum allowable concentration are increasingly present in the waters. Even after the water treatment, it happens that some components are still in the drinking water, which adversely affects human health. ...Jovana Nikolić, Vesna Ristić Vakanjac. "Karst wastewater as a high quality, renewable and within the circular economy water resource" 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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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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Speleo‐morphology and tectonic processes – What can be seen in slowly deforming regions?
Ana Mladenović, Jelena Ćalić (2022)There are a lot of methods used to determine tectonic process active in a region, and they vary depending on the purpose of the research. However, a number of them cannot be used in slowly deforming regions, because the effects of active tectonic process on the rocks in such regions could be negligible. This is especially true for the recently active tectonics in such regions, since most of the recently active tectonic structures never reach the surface. Because of ...Ana Mladenović, Jelena Ćalić. "Speleo‐morphology and tectonic processes – What can be seen in slowly deforming regions?" in 18th International Congress of Speleology, Savoie Mont Blanc, 24-31 July 2022, Postojna : International Union of Speleology (2022)