Претрага
1817 items
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Approximation of the number of roots that do not lie on the unit circle of a self-reciprocal polynomial
Dragan Stankov (2024)We introduce the ratio of the number of roots not equal to 1 in modulus of a reciprocal polynomial Rd(x) to its degree d. For some sequences of reciprocal polynomials we show that the ratio has a limit L when d tends to infinity. Each of these sequences is defined using a two variable polynomial P(x,y) so that Rd(x) = P(x,xn). For P(x,y) we present the theorem for the limit ratio which is analogous to the Boyd-Lawton limit formula ...Dragan Stankov. "Approximation of the number of roots that do not lie on the unit circle of a self-reciprocal polynomial" in The book of abstracts XIV symposium "mathematics and applications” Belgrade, Serbia, December, 6–7, 2024 , Univerzitet u Beogradu, Matematički fakultet (2024) М64
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Industrija 4.0 - koncept prediktivnog održavanja 4.0 (PdM 4.0) u rudarstvu
Četvrtu industrijsku revoluciju – Industriju 4.0 karakteriše upotreba cyber-fizičkih sistema. Da bi se postigla optimalna strategija održavanja (ali i eksploatacije), neophodno je razviti sisteme koji podržavaju napredne inteligentne sisteme održavanja ili tehnologije pametnog održavanja. Iz toga su proizašli postulati Prediktivnog održavanja 4.0 (PdM 4.0) koji definišu veoma blisku budućnost u oblasti održavanja tehničkih sistema pa i rudarske opreme. PdM 4.0 uključuje iskorišćenje snage veštačke inteligencije za stvaranje stalnog uvida u otkrivanje uzroka i anomalija u radu opreme, koje se ...Predrag Jovančić, Vesna Damnjanović, Dragan Ignjatović, Miloš Tanasijević, Stevan Đenadić. "Industrija 4.0 - koncept prediktivnog održavanja 4.0 (PdM 4.0) u rudarstvu" in IX Međunarodna konferencija UGALJ 2019, Zlatibor, Srbija, 23-26. oktobar 2019., Jugoslovenski komitet za površinsku eksploataciju (2019) М33
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Solid state synthesis of extra phase-pure Li4Ti5O12 spinel
Фазно чист спинел Li4Ti5O12 са величином честица мањом од 500 nm добијен је реакцијом у чврстом стању из стехиометријске смеше наноанатаса (ТiО2) и Li2CO3 која је претходно активирана механохемијским поступком. Реакција у чврстом стању у потпуности се завршава за само 4 часа на температури од 800 ºC. Уз помоћ XRPD, SEM и TG/DSC анализе испитане су структурне и микроструктурне карактеристике добијеног спинела, механизам реакције између анатаса и Li2CO3, као и термичка стабилност Li4Ti5O12. Реакција започиње разлагањем Li2CO3 на температурама ...дифракција рендгенских зрака, механизам реакције, термичка стабилност, Li4Ti5O12, спинел, фазно чист узоракIvana Veljković, Dejan Poleti, Ljiljana Karanović, Miodrag Zdujić, Goran Branković. "Solid state synthesis of extra phase-pure Li4Ti5O12 spinel" in Science of Sintering, National Library of Serbia (2011). https://doi.org/10.2298/SOS1103343V М23
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Unusually sluggish microemulsion system with water, toluene and a technical branched alkyl polyethoxylate
Marija Ilić, Franz-Hubert Haegel, Vesna Pavelkić, Snežana Zlatanović, Zoran Marković, Aleksandar Cvjetić (2015)Microemulsion systems with water, toluene and nonionic surfactants are interesting for application due to the excellent solvent properties of aromatic hydrocarbons. In this study, the pseudo-binary phase diagram (“fish-diagram”) of such a ternary system was investigated using a branched technical alkyl polyethoxylate. Lutensol ON 50 (i-C10E5) was considered a suitable surfactant. The system with technical branched i-C10E5 exhibits very long, and for compositions near optimum solubilization, i.e., the minimum content of surfactant needed for a bicontinuous microemulsion, extremely long ...микроемулзија, толуен, оксоалкохол етоксилат, термодинамичка стабилност, тернарни фазни дијаграми, дијаграми „fish“Marija Ilić, Franz-Hubert Haegel, Vesna Pavelkić, Snežana Zlatanović, Zoran Marković, Aleksandar Cvjetić. "Unusually sluggish microemulsion system with water, toluene and a technical branched alkyl polyethoxylate" in Chemical Industry and Chemical Engineering Quarterly (2015). https://doi.org/10.2298/CICEQ141012045I М23
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A contribution to the understanding of hydrochemical properties of thermomineral water on the L’dži locality (eastern part of North Macedonia)
Hristina Petrova, Katarzyna Wątor, Piotr Rusiniak, Boris Vakanjac, Vesna Ristić Vakanjac, Ewa Kmiecik (2023)Regarding the aspect of mineral, thermo-mineral, and thermal waters, on the territory of the Republic of North Macedonia, there are 65 registered locations, of which 8 are categorized as spas. This includes the Kežovica spa, also known as the Štipska spa. In the vicinity of Kežovica Spa is the thermo-mineral L’Dži spring with mineralization around 1.3 g/L and the water temperature at the time of sampling was 50.1 °C. Spring L’Dži is generated by a fault structure and is ...termomineralne vode, hemizam voda, hidrohemijske karakteristike, lokalitet L’dži, Republika Severna MakedonijaHristina Petrova, Katarzyna Wątor, Piotr Rusiniak, Boris Vakanjac, Vesna Ristić Vakanjac, Ewa Kmiecik. "A contribution to the understanding of hydrochemical properties of thermomineral water on the L’dži locality (eastern part of North Macedonia)" in Review of the Bulgarian Geological Society, Bulgarian Geological Society (2023). https://doi.org/10.52215/rev.bgs.2023.84.3.303 М23
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The mean value of the Riemann zeta-function on the critical line
Ivić Aleksandar (2014)Ivić Aleksandar. "The mean value of the Riemann zeta-function on the critical line" in Analytic Number Theory, Approximation Theory, and Special Functions, New York, USA:Springer (2014): 3-68. https://doi.org/10.1007/978-1-4939-0258-3\_1 M21
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Investigating distant effects of the Moesian promontory: Brittle tectonics along the western boundary of the Getic unit (East Serbia)
In this study, we report evidence for brittle deformation in a part of the Carpatho–Balkan orogen, which is explained in terms of effects of the rigid Moesian promontory of the European plate on fault kinematics in East Serbia. We focus on the westernmost part of the Getic Unit of the East Serbian Carpatho–Balkanides, i.e. the Gornjak–Ravanica Unit, located between two main thrusts that were repeatedly activated from Early Cretaceous to recent times. We combine a new data set on ...Getikum, Mezijska jedinica, Karpato-balkanski orogen, krte deformacije, Gornjačko-ravanička jedinicaAna Mladenović, Milorad D. Antić, Branislav Trivić, Vladica Cvetković. "Investigating distant effects of the Moesian promontory: Brittle tectonics along the western boundary of the Getic unit (East Serbia)" in Swiss Journal of Geosciences, Springer (2019). https://doi.org/10.1007/s00015-018-0324-5 М22
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Design and drilling of wells in formations with high pressure
Vojin Solomun (2024)Objectives of this Thesis are to: - Develop an awareness of the challenges presented from elevated temperatures and pressures in well construction. - Learn the key differences between ―normal‖ condition wells and HPHT wells. - Understand some of the indicators of thermal- and pressure-related problems. - Understand the responses which may be made to mitigate high pressure and high temperature ,,HPHT‘‘ challenges while drilling wells. HPHT wells are an unavoidable consequence of the ever expanding search for oil and gas resources around the world. As wells are ...Vojin Solomun. Design and drilling of wells in formations with high pressure, 2024
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Underground loading-haulage equipment selection with application of topsis method with different weighting methods of criteria
The choice of adequate mining machines is one of the most complex problems in the underground exploitation of mineral raw materials. The weight of such a decision is reflected in the high prices of these machines and the occurrence of even greater costs during their use if their choice was wrongly conceived. There are numerous examples from practice in which such decisions were made solely on the basis of comparing the prices of machines, without considering any of the ...utovarno-transportna mehanizacija, izbor, TOPSIS, entropija, standardna devijacija, težina kriterijumaVladimir Krivošić, Luka Crnogorac, Rade Tokalić. "Underground loading-haulage equipment selection with application of topsis method with different weighting methods of criteria" in Underground mining engineering, University of Belgrade - Faculty of Mining and Geology (2024) М51
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Landslide Susceptibility Analysis of Belgrade City Area
Marjanović Miloš, Đurić Uroš, Abolmasov Biljana, Bogdanović Snežana. "Landslide Susceptibility Analysis of Belgrade City Area" in Landslide science for a safer geoenvironment - the international programme on landslides (IPL) 2, Berlin, Germany:Springer (2014): 469-474. https://doi.org/10.1007/978-3-319-05050-8_73 M13
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Reconnaissance study of active sulfide springs and cave systems in the southern part of the Sulaimani Governorate (NE Iraq)
Iurkiewicz Adrian A., Stevanović Zoran (2010)Iurkiewicz Adrian A., Stevanović Zoran. "Reconnaissance study of active sulfide springs and cave systems in the southern part of the Sulaimani Governorate (NE Iraq)" in Carbonates and Evaporites 25 no. 3, :Springer (2010): 203-216. https://doi.org/0.1007/s13146-010-0024-3 M23
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Crystal structure of the tetragonal polymorph of bis(1-ethyl-3-methylimidazolium) tetrabromidocadmate
Đordević Tamara, Gerger Sabrina, Karanović Ljiljana. "Crystal structure of the tetragonal polymorph of bis(1-ethyl-3-methylimidazolium) tetrabromidocadmate" in Acta Crystallographica, Section E-Crystallographic Communications E72 no. part 7, 2 Abbey SQ, Chester, CH1 2HU, England :International Union Crystallography (2016): 1013-1016. https://doi.org/10.1107/S2056989016009919 M54
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(3+1)-Incommensurately modulated crystal structure of Cs3ScSi6O15
Hejny Clivia, Kahlenberg Volker, Schmidmair Daniela, Dabić Predrag. "(3+1)-Incommensurately modulated crystal structure of Cs3ScSi6O15" in Acta Crystallographica Section B: Structural Science, Crystal Engineering and Materials 72 no. 1, Chester, England :International Union of Crystallography (2016): 109-116. https://doi.org/10.1107/S2052520615022076 M21
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Design of a sucker rod pumping system
Ana Ponoćko (2024)For a long time in the history of oil production, sucker rod pumps have been the first and in many cases the only choice when it comes to mechanical extraction methods. Proper selection of each individual element of the system enables optimization, which entails benefits in the form of increased efficiency and reduced costs. The first part of the paper presents the underground and surface equipment of the rod pump and describes the operation of the entire system. The ...Ana Ponoćko. Design of a sucker rod pumping system, 2024
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Optimizacija površinskog kopa Ciganuša – Škorac
Vasilije Zejak (2024)U radu se govori o značaju optimizacije u savremenom rudarstvu i kako nam to softveri štede vreme, novac i olakšavaju procese planiranja.Konkretno u izradi ovog rada korišćen je softverski paket Whittle.Da bi se optimizacije mogla uspešno sprovesti, potrebno je konstruisati pre svega blok model ležišta kao i definisati niz tehno – ekonomskih parametara. Na osnovu tih podataka definiše se optimalna kontura i dinamika razvoja radova. U skladu sa definisanim podaci i odgovarajućim podlogama definisana je optimalna kontura površinskog kopa Ciganuša ...optimizacija, površinski kop Ciganuša - Škorac, blok model, strateško planiranje, optimalna kontura, dinamika razvoja, fazni razvojVasilije Zejak. Optimizacija površinskog kopa Ciganuša – Škorac, 2024
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Kvartarni klastiti iz bušotine kod Aranđelovca (rasadnik Mladost)
Miroslav Radeta (2024)U ovom radu analizirani su kvartarni klastiti iz bušotine kod Aranđelovca IB 18-3, sa ciljem boljeg razumevanja njihovih sedimentoloških i litoloških karakteristika. Kvartarni sedimenti su prilično homogenog/uniformisanog sastava i čine ih finozrni klastiti (dominantno alevroliti) sa određenim procentom peskovite i glinovite frakcije. Oni su iskartirani u samoj povlati i debljina im je 27 m. U podini su gornjokredne karbonatne stene (krečnjaci, laporci, rekristalisali/mermerisani karbonati) i miocenski sediment predstavljeni raznovrsnim varijetetima klastično karbonatnih stena. Ispitivani kvartarni sedimenti odlikuju se odsustvom ...Miroslav Radeta. Kvartarni klastiti iz bušotine kod Aranđelovca (rasadnik Mladost), 2024
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Tektonska evolucija istočne periferije timočke eruptivne oblasti
Stefan Zujić (2024)U radu su predstavljeni rezultati proučavanja tektonskih i litostratigrafskih karakteristika istočnog oboda Timočke eruptivne zone. Zaključci o geološkim odnosima u okviru Timočke eruptivne oblasti i susednih geotektonskih jedinica izvedeni su na osnovu podataka prikuljenih tokom terenskih istraživanja i podataka dobijenih iz publikovanih radova. Rezultati rada ukazuju da je teren koji je bio tema ovog istraživanja, u strukturno-tektonskom smislu oblikovan tokom glavnih geodinamičkih događaja u okviru Karpato-balkanskog orogenog luka. Analizom strukturnog sklopa su utvrđeni glavni deformacioni događaji koji su predsavljeni ...Stefan Zujić. Tektonska evolucija istočne periferije timočke eruptivne oblasti, 2024
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Mineralni i hemijski sastav čestica u atmosferi zone Kolubarskog basena i uticaj na životnu sredinu
Željko R. Cvetković (2013-11-18)Čestice iz vazduha su prikupljane u blizini termoelektrane i površinskih kopovarudnika uglja u Kolubarskom basenu. Izmereni srednji sadržaji koncentracija rastvornih,nerastvornih i ukupnih taložnih materija na godišnjem nivou prelaze 200 mg/m2dan (K-1, K-3, K-4, K-5). Distribucija čestica na svim lokacijama klasifikovana je na česticeveličine veće od 10 μm, zatim na čestice veličine od 10 μm do 2,5 μm i klase česticaveličine ispod 2,5 μm. Ovakva podela je dala odnos koncentracija inhalatornih irespiratornih čestica po mernim mestima. Skenirajuća elektronska mikroskopija jepokazala ...mineral, četica, prašina, leteći pepeo, aerosediment, PM10, teški metali,koncentracija, veličina čestice, KolubaraŽeljko R. Cvetković. "Mineralni i hemijski sastav čestica u atmosferi zone Kolubarskog basena i uticaj na životnu sredinu" in Универзитет у Београду, Универзитет у Београду, Рударско-геолошки факултет (2013-11-18)
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Mineralni i hemijski sastav čestica u atmosferi zone Kolubarskog basena i uticaj na životnu sredinu
Željko R. Cvetković (2013-11-18)Čestice iz vazduha su prikupljane u blizini termoelektrane i površinskih kopovarudnika uglja u Kolubarskom basenu. Izmereni srednji sadržaji koncentracija rastvornih,nerastvornih i ukupnih taložnih materija na godišnjem nivou prelaze 200 mg/m2dan (K-1, K-3, K-4, K-5). Distribucija čestica na svim lokacijama klasifikovana je na česticeveličine veće od 10 μm, zatim na čestice veličine od 10 μm do 2,5 μm i klase česticaveličine ispod 2,5 μm. Ovakva podela je dala odnos koncentracija inhalatornih irespiratornih čestica po mernim mestima. Skenirajuća elektronska mikroskopija jepokazala ...mineral, četica, prašina, leteći pepeo, aerosediment, PM10, teški metali,koncentracija, veličina čestice, KolubaraŽeljko R. Cvetković. "Mineralni i hemijski sastav čestica u atmosferi zone Kolubarskog basena i uticaj na životnu sredinu" in Универзитет у Београду, Универзитет у Београду, Рударско-геолошки факултет (2013-11-18)
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Parallel Stylometric Document Embeddings with Deep Learning Based Language Models in Literary Authorship Attribution
This paper explores the effectiveness of parallel stylometric document embeddings in solving the authorship attribution task by testing a novel approach on literary texts in 7 different languages, totaling in 7051 unique 10,000-token chunks from 700 PoS and lemma annotated documents. We used these documents to produce four document embedding models using Stylo R package (word-based, lemma-based, PoS-trigrams-based, and PoS-mask-based) and one document embedding model using mBERT for each of the seven languages. We created further derivations of these ...Mihailo Škorić, Ranka Stanković, Milica Ikonić Nešić, Joanna Byszuk, Maciej Eder. "Parallel Stylometric Document Embeddings with Deep Learning Based Language Models in Literary Authorship Attribution" in Mathematics, MDPI AG (2022). https://doi.org/10.3390/math10050838 М21а