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Упит dcterms_creator_txt:Nikolić Aleksandar S.

1421 items

  • Синтеза и карактеризација керамике на бази сфена

    Jelena R. Pantić (2015-07-10)
    Механохемијска активација стехиометријске смеше реактаната TiO2, SiO2 и CaCO3 показала се као веома успешна и једноставна метода за добијање сфена (CaTiSiO5). На основу мерења релативних густина свих синтерованих узорака установљено је да максималну густину од 93,9 % имају узорци који су активирани 30 минута и синтеровани на 1200 °С. Микроструктурном анализом, тј. анализом слика синтерованих узорака активираних 30 минута, које су добијене скенирајућом електронском микроскопијом, опажа се бимодална расподела величине зрна, са просечном величином од 3 μm, односно 5 ...
    сфен, механохемија, Ритвелдова метода, оптичка спектроскопија, микроструктурна анализа, фазна трансфоpмација, чврсти раствори
    ... за добијање сфена (CaTiSiO5).  Промена густине испресованих узорака праћена је у изотермским условима на температурама 900 °С, 1000 °С, 1100 °С, 1200 °С и 1250 °С у временском периоду од 2 сата. Уочено је да густине свих узорака расту са температуром синтеровања. Максималну густину 93,9 % ...
    ... геометрије и микроструктурних параметера унутар система, процес синтеровања се може поделити на три карактеристичне фазе (Ристић, 1993; Ристић и Николић, 1987; Ивенсен, 1985; German, 1996; Маричић и коаутори, 1998). Најједноставнији модел је модел две сфере у две димензије, при чему се прати њихово ...
    ... Докторска дисертација Јелена Пантић 120 Катанић-Поповић Ј., Митков М., Николић Љ.Н., Петковић Ј., Ристић М.М., Самсонов Г.В., Степанчук А., Ускоковић Д.П., Живановић Б. и Живковић М. (1973) Металургија праха: физички и фи ...

  • Rudna mikroskopija

    Aleksandar Pačevski (2018)
    mikroskopija ruda

  • Manganese-pyromellitate complex as a precursor for preparation of spinel Mn3O4

    Lidija Radovanović, Željko Radovanović, Aleksandar Kremenović, Bojana Simović, Milica V. Vasić, Jelena Rogan (2022)
    In recent years, thermal decomposition studies of transition metal complexes with benzenepolycarboxylate ligands have become an area of a great importance due to the possibility of obtaining useful metal oxides with desirable electrical, magnetic and catalytic properties [1]. As a contrast to conventional methods for the preparation of metal oxides, such as hydrothermal or sol–gel treatment, thermolysis is faster, more efficient ...

  • Environmental Noise Impact Assessment for Large-Scale Surface Mining Operations in Serbia

    Uros Pantelic, Petar Lilic, Aleksandar Cvjetic, Nikola Lilic (2023)
    Noise emissions are a significant environmental impact caused by the mining industry in all technological phases of surface mining, mineral processing, and waste disposal. This paper presents the role of noise impact assessment and control in large-scale surface mining operations. Mine planning develops the model of mining operations, ore excavation, and waste dumping scheduling and processing rates, including spatial distribution of mining activities. Such a level of mine planning requires an environmental impact assessment study. This can be achieved ...
    mine planning, noise impact assessment, mining, noise mapping, environmental impact assessment

  • Structural and microstructural study of brookite based TiO2 nanocomposites with carbon black (C)

    Aleksandar Kremenović, Mirjana Grujić-Brojčin, Nataša Tomić, Maja Šćepanović (2022)
    Structural and microstructural properties of TiO2-based nanocomposites with carbon black (C), synthesized by sol-gel-hydrothermal method, have been studied by XRPD and Raman scattering. Detailed size-strain analyses of XRPD and Raman scattering results are presented in order to investigate the influence of C content on brokite and anatase phase formation. The XRPD size-strain analyses have resulted in reliable structure and microstructure results for both anatase and brookite and their relative abundance ratio has been refined by Rietveld method. The brookite ...

  • Applicability of the risk ranking methodology designed for water reservoirs to tailings storage facilities

    Dragana Nišić, Dinko Knežević, Aleksandar Cvjetić, Neda Nišić, Vladimir Jovanović (2022)
    The risks associated with operating water reservoirs and tailings storage facilities (TSFs) are different because of their different purposes, methods of construction and operation, and characteristics of the materials impounded and their flow behaviour. Regardless of the differences, these two types of structures are often put in the same category when it comes to risk assessment and the application of relevant methodologies, which may result in unrealistic outcomes. In this paper we investigate whether it is possible to apply ...
    procena rizika, akumulacije za vodu, jalovište, TSF, ICOLD, FMEA

  • Effect of natural gas composition on methane number: A case of gas reservoirs in Serbia

    Marija Živković, Milica Ivić, Dejan Ivezić, Aleksandar Madžarević (2017)
    Natural gas is considered as the most environmentally acceptable fossil fuel, thus it is an alternative to petroleum derivate, dominantly used in internal combustion engines. Physical properties of a fuel as well as behavior during combustion process are affected by its composition. This article presents analysis of effect of natural gas composition on methane number (MN), conducted for natural gas deposits in Serbia. For empirically determination of MN: California air resources board (CARB) method and Linear and Anstalt für ...
    Састав, метански број, природни гас

  • Applying the Fuzzy Inference Model in Maintenance Centered to Safety: Case Study – Bucket Wheel Excavator

    Predrag Jovančić, Miloš Tanasijević, Vladimir Milisavljević, Aleksandar Cvjetić, Dejan Ivezić, Uglješa Bugarić (2020)

  • 125 godina Srpskog geološkog društva (1891-2016) (125 years of the Serbian Geological Society)

    Rundić Ljupko, Grubić Aleksandar, Banjac Nenad, Sudar Milan & Stevanović Zoran"" (2016)

  • The influence of structural modification of Pd(II) pincer-type complexes on the kinetics of substitution reactions

    Snežana Jovanović Stević, Snežana Radisavljević, Aleksandar Mijatović, Biljana Petrović, Ana Kesić (2023)
    This mini-review summarizes the kinetic data obtained for the substitution reactions of some palladium(II) complexes containing bis-pyrazolylpyridine derivatives as pincer-type ligands with biologically significant nitrogen- and sulfur-donor biomolecules as nucleophiles. Three structurally different palladium(II) complexes were selected: [Pd(L1)Cl]+ (Pd1), [Pd(L2)Cl]+ (Pd2) and [Pd(L3)Cl]+ (Pd3) (where L1 = bis(2-(1H-pyrazol-1-yl)ethyl)amine, L2 = 2,6-bis(5-(tert-butyl)-1H-pyrazol-3-yl)pyridine, and L3 = 2,6-bis(5-(tert-butyl)-1-methyl-1H-pyrazol-3-yl)pyridine, while for the entering nucleophiles were used thiourea (Tu), L-methionine (L-met), and guanosine-5’-monophosphate (5’-GMP). Kinetic measurements were carried out for all systems as pseudo-first ...

  • Security of Supply as a Major Part of the Energy Security Puzzle

    Aleksandar Madžarević, Miroslav Crnogorac (2022)
    Sigurnost snadbevanja prirodnim gasom Republike Srbije se kroz poslednje dve decenije tretira kao hitno, strateško, političko i bezbednosno pitanje. U sektoru prirodnog gasa, Republika Srbija je veoma zavisna od gasa koji uvozi iz Rusije. Indikatori sigurnosti snadbevanja predstavljaju jedan od osnovnih elemenata za određivanje energetske bezbednosti i snažne alate za usmeravanje energetskog sektora ka održivom razvoju. Metodolaška analiza prikazana u radu je bila koncentrisana na pokazatelje sigurnosti snadbevanja u oblasti energetske bezbednosti koji se odnose na sektor prirodnog gasa ...
    energetska bezbednost, sigurnost snabdevanja, energetski indikator, dostupnost energije, diversifikacija izvora i pravaca

  • Possibilities for Reduction of Energy-Related Air Pollution in Serbia - Exploring Energy Scenarios

    Marija Živković, Boban Pavlović, Dejan Ivezić, Aleksandar Mijatović (2023)
    Fossil fuels and biomass account for almost 93% of the total primary energy supply in Serbia. Meeting the energy needs of consumers implies a transformation of the chemical energy of fuels through combustion processes to obtain heat that can be utilized as such, or further transformed into mechanical or electrical energy. These processes have an undeniable impact on air pollution, even in cases of biofuels or hydrogen combustion. Possibilities for air pollution reduction are identified, both on the supply ...
    загађење ваздуха, сценарији енергетског развоја, Србија

  • Challenges in using wastewater heat pumps in district heating systems

    Dejan Ivezić, Marija Živković, Aleksandar Madžarević, Boban Pavlović, Dušan Danilović, Dimitrije Manić (2022)
    Decarbonization of district heating systems requires ensuring significant amounts of renewable energy available in the proximity of the district heating network. One of the promising solutions is the utilization of purified water from wastewater treatment plants by heat pumps. However, as a heat source, wastewater treatment plants are characterized by annual variability of the flow and temperature of purified water. The consequence is the variability of recoverable heat potential. In this paper, the effect of variability is analyzed for ...
    Toplotna pumpa, Daljinsko grejanje, Postrojenje za prečišćavanje otpadnih voda

  • Strategic Environmental Assessment and the precautionary principle in the spatial planning of wind farms – European experience in Serbia

    Boško Josimović, Aleksandar Cvjetić, Danilo Furundžić (2021)
    Spatial determination planning is at an initial and very sensitive step in the development of wind farms. On one hand, it is important to maximize the potential of wind in a particular area, and on the other hand, it is important to achieve environmental protection (including the human population and natural heritage) in the same space at the same time. With this in mind, it is important to balance all the requirements that are relevant for reaching the optimal ...
    Obnovljiva energija, Održivost, Životna sredina

  • 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“

  • Proizvodnja električne energije iz elektrana na ugalј i prateća emisija CO2: komparacija EU-27 i Srbije

    Aleksandar Madžarević, Predrag Jovančić, Stevan Đenadić, Filip Miletić, Miroslav Crnogorac (2023)
    Velike elektrane su i u trećoj deceniji 21. veka i dalјe odgovorne za više od polovine proizvodnje električne energije u Evropi. U svom radu pretežno koriste fosilna goriva, što rezultira emisijom zagađujućih materija u vazduh. Stoga, zahvalјujući direktivama EU, kao i poremećajima na tržištu, emisije uglјen-dioksida iz velikih postrojenja za sagorevanje u EU-27 intenzivno se smanjuju u poslednje dve decenije. Iako je upotreba uglјa, posebno u zemlјama Evropske unije, u stalnom padu, ima prostora za dodatno smanjenje. Autori su ...
    CO2, emisija, ugalј, termoelektrane, EU-27, Srbija

  • Univerzitet u Beogradu Rudarsko-geološki fakultet Master rad Modeliranje disperzije prašine u životnoj sredini u fazi proširenja P.K. Veliki Krivelj

    Magdalena Milanović (2024)
    Modeliranje disperzije zagađenja životne sredine predstavlja proces u kom se korišćenjem matematičkih modela vrši simulacija širenja i raspodele zagađenja u životnoj sredini, koje nastaje određenim aktivnostima. Modeliranje nam pomaže da predvidimo zagađenja koja dobijamo planiranim aktivnostima u zemljištu, vodi i/ili atmosferi određene regije, kako bi na vreme preduzeli odgovarajuće preventivne mere kojim se smanjuje ili upotpunosti eminiše uticaj na životnu sredinu i zdravlje ljudi. Glavni zadatak ovog rada je procena uticaja, projekta proširenja kopa Veliki Krivelj, na kvalitet vazduha. Rezultati koji ...
    Modeliranje disperzije zagađenja životne sredine, površinski kop Veliki Krivelj, AERMOD, zagađenje vazduha, disperzija prašine
    ... G R O U M AM J ARAOOC 486700 5 5 Y E A R S FO R S O U R C OA | — | A V E R A G E D AC MR ' Ma x. 25 0 [u g/ m" 3| at ( 7 5 8 9 5 0 0 00 . 48 87 50 0 00 ) PL OT FI LE OF A N N U A L V A L U E S | Slika 10.4 Rasprostiranje suspendovanih čestica ...
    ... prosečni period usrednjavanja prikazan je na s/ici 70.6. U ovom slučaju koncentracije NO» u zoni naselja Krivelj i Oštrelj su ispod propisane granične vrednosti (40 ng/m*). [12] 6 YE GA RS FO R SO UR CU E GR OG gp ev lL . % A V E R A G E D A C R O S S 76 0 (u g/ m" 3) 1 (7 50 05 ...
    ... Magdalena Milanović, R517/23 Beograd, 2024. Komisija: 1. prof. dr Nikola Lilić, mentor Rudarsko-geološki fakultet, Beograd 2. prof. dr Aleksandar CvJetić, član Rudarsko-geološki fakultet, Beograd 3. prof. dr Vladimir Milisavljević, član Rudarsko-geološki fakultet, Beograd Datum odbranje: ...

  • Димензионисање система завојних пумпи

    Марија Дивац (2024)
    Овај завршни рад се бави димензионисањем система завојних пумпи (Progressive Cavity Pumps - PCP) које се широко користе у нафтној и гасној индустрији, нарочито за подизање тешких и вискозних флуида. Завојне пумпе су се показале као ефикасно решење у бушотинама са сложеним условима,захваљујући својој способности да транспортују флуиде са високим садржајем чврстих честица и гаса.Рад обухвата анализу кључних параметара као што су вискозност, густина, дубина бушотине и притисак, који су пресудни за избор одговарајуће пумпе.Применом софтверског алата извршена је ...
    завојне пумпе, димензионисање, експлоатација нафте, вискозни флуиди, софтверска симулација, PCP пумпе
    ... 3a paJi IIyMIe: P-Q'·H·p:g, m Ine cy: P – norpe0Ha cHara nyMme (W), Q – nporok (m?/s), H – BHcHHa nojmH3ahba HH IIpHrHcakK (m), p – rycraHa Oonmyuana (kg/m*), g – rpaBHranmuoHa KoHcTaHra (9.81 m/s?), 1) — e(-)HKaCHOCT CHCTEMAa. 3a onmTHMHnalHjy JHMCH3HOHHCAaHba CHCTEMA4, HCOTIIXOJIHO ...
    ... oJipeljiBapbe CHaTe ITyMTIc je: P-Q'·H·p:g, m Ine cy: P – cHara nyMne (W), Q – nporok (inyaana (m?/s), H – npuruacak (m), p – rycraHa Oonmyuana (kg/m*), g – rpaBHranmuoHa KoHcTaHra (9.81 m/s?), 1) — e(-)HKaCHOCT CHCTEMAa. CodQrBepcku anmara 31 mnpopauyH: PumpSizer, CFD camyanuje (Computational ...
    ... New Generation of Progressive Cavity Pump in a High GOR A4rgentinian Heavy Oil Field; 35. Sathyamoorthy, S., Stezn, A., McGilvray, J., Fuchs, H., Ainebyona, B., Kyomugisha, P., Vijapurapu, S., Kagga, N., Rindfuss, R., Basiima, D., 2012., First 4Application of Progressive Cavity Pumps for 4ppraisal ...

  • Influence of Post-Synthesis Treatments on the Properties of Brushite/Monetite Powders

    Željko Radovanović, Lidija Radovanović, Aleksandar Kremenović, Đorđe Janaćković, Rada Petrović (2022)
    Dicalcium phosphate (DP) materials, of which brushite and monetite were the most known, have been intensively studied for several decades because of excellent resorptive and osteoconductive properties that can satisfy the requirements needed for various medical applications, such as bone cements, coatings of metallic implants and bone grafts ...

  • Micro- to nanoscale textures of gold in arsenopyrite and scorodite from the As-Au-Bi assemblage of Drenjak locality (Serbia)

    Ivana Jelić, Janez Zavašnik, Marina Lazarov, Alena Zdravković, Sabina Kovač, Jovica Stojanović, Aleksandar Pačevski (2023)
    Arsenopyrite and pyrite are important carriers of Au that is present in the form of microscopic and “invisible” gold. Such gold can be expected to be released upon the process of oxidation of these sulfides. In studied gold mineralization at Drenjak, related to the granitoids of the Oligocene-Miocene Kopaonik Ore District, the main arsenopyrite-pyrite-(bismuthinite) sulfide assemblage was formed in the quartz bodies and partly replaced by scorodite (FeAsO4·2H2O) and Bi-arsenate. With only up to 5 ppm of gold recorded ...
    Economic Geology, Geochemistry and Petrology, Geology