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Упит dcterms_subject_txt:Standards for LRs

1390 items

  • Synthesis of MnCo2O4 nanoparticles as modifiers for simultaneous determination of Pb(II) and Cd(II)

    Vesna Antunović, Marija Ilić, Rada Baošić, Dijana Jelić, Aleksandar Lolić (2019)
    The porous spinel oxide nanoparticles, MnCo2O4, were synthesized by citrate gel combustion technique. Morphology, crystallinity and Co/Mn content of modified electrode was characterized and determined by Fourier transform infra-red spectroscopy (FT-IR), scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), X-ray diffraction pattern analysis (XRD), simultaneous thermogravimetry and differential thermal analysis (TG/DTA). Nanoparticles were used for modification of glassy carbon electrode (GCE) and new sensor was applied for simultaneous determination of Pb(II) and Cd(II) ions in water samples with the ...
    MnCo2O4 nanočestice, modifikatori, određivanje Pb (II) and Cd(II)

  • Cytotoxic activity of tetradentate Schiff Base Copper(II) complexes

    Nevenka Gligorijević, Aleksandar Mijatović, Sandra Aranđelović, Rada Baošić (2021)
    Istraživanje kompleksa bakra kao potencijalnih antikancerogenih agenasa nudi ohrabrujuće perspektive u odnosu na komplekse platine (II) računajući na smanjenu toksičnost, novi mehanizam delovanja, različit spektar aktivnosti i perspektivu neunakrsne rezistencije. Kompleksi Šifovih baza bakra(II) koji sadrže tetradentatne ligande acac2en tipa (acac2en (1); tfacac2en (3), acactfacacen (4), acacphacacen (6)) pokazali su važnu antioksidativnu aktivnost, visok potencijal za interakciju sa HSA i DNK, u prethodnim studijama. Zbog toga je bilo interesantno ispitati i uporediti potencijal antikancerogene aktivnosti in vitro, u odnosu ...
    Bakar(II) kompleksi, citotoksičnost, ćelijski ciklus

  • Composition of organic matter and thermal maturity of Mesozoic and Cenozoic sedimentary rocks in East Herzegovina (External Dinarides, Bosnia and Herzegovina)

    Nikoleta Aleksić, Aleksandar Kostić, Miloš Radonjić (2021)
    This paper presents the first data on the organic matter and thermal maturity of Mesozoic and Cenozoic sedimentary rocks in the East Herzegovina region of the External Dinarides. Representative, organic-rich samples from outcropping sedimentary rocks of different ages in the area (Triassic to Neogene) were selected and analysed. The organic matter was studied by Rock-Eval pyrolysis and under the microscope in reflected non-polarized light and incident blue light. The results obtained show the presence of different types of organic ...
    nafta i gas, Rock-Eval, refleksija vitrinita, maceral, termička zrelost
    ... range for the oil window, T max is not a reliable maturity indicator for sediments with kerogen type I. T max is also not suitable for source rocks containing kerogens that generate petroleum at a lower level of maturity (Tegelaar and Noble, 1994; Hunt, 1996; Yang and Hors�eld, 2020) or for low-TOC ...
    ... range for the oil window, Tnax is not a reliable maturity indicator for sediments with kerogen type I. T max is also not suitable for source rocks containing kerogens that generate petroleum at a lower level of maturity (Tegelaar and Noble, 1994; Hunt, 1996; Yang and Horsfield, 2020) or for low-TOC ...
    ... rocks to be mis- identi�ed as source rocks. Fig. 8. Cross-plot between %Rr and Tmax (after extraction) for analyzed samples. 10 N. ALEKSIC ET AL. Data sets for vitrinite reflectance are given for all local- ities, where the sediments contained an adequate amount of phytoclasts, ie., vitrinite and huminite ...

  • Definition of groundwater genesis and circulation conditions of the complex hydrogeological karst system Mlava–Belosavac–Belosavac-2 (eastern Serbia)

    Ljiljana Vasić, Saša Milanović, Zoran Stevanović, Laszlo Palcsu (2020)
    Geochemistry and Petrology

  • Late and post-collisional tectonic evolution of the Adria-Europe suture in the Vardar Zone

    Emő Márton, Marinko Toljić, Vesna Cvetkov (2022)
    The Vardar Zone is a product of the Triassic-Jurassic opening of the Neotethys, Jurassic obduction, Late Cretaceous/Paleogene consumption of the oceanic crust and continental collision. During the last process, the Eastern Vardar Zone was thrust over the Central and eventually both onto the Western Vardar Zone. The present paleomagnetic and structural study provided new results from the first two zones in the Belgrade area. The younger set of data, together with published ones from the third zone, provide firm ...
    Adria–Europe suture, Vardar Zone, Paleomagnetism, Thrusting, Vertical axis rotation

  • Mitigating hydrate formation in onshore gas wells: A case study on optimization techniques and prevention

    Milica Ješić, Bojan Martinović, Stefan Stančić, Miroslav Crnogorac, Dušan Danilović (2023)
    Gas wells, particularly those situated onshore, play a vital role in the global energy sector by supplying a significant portion of natural gas. However, operational challenges, notably gas hydrate formation, pose substantial issues, leading to complications such as flowline blockages and unexpected well shutdowns. Gas hydrates, crystalline structures resembling ice, ...
    Gas Well, Gas Hydrate Formation, Well Modeling, Well Performance Optimization, Choke Position Adjustments, Methanol Injection

  • Развој модела конструкције просторија отварања рудника са подземном експлоатацијом

    Dražana M. Tošić (2016-08-26)
    Приликом израде подземних просторија у стјенској маси долази до нарушавања природне равнотеже напонских стања стијенског масива који су владали прије израде тих просторија, при чему долази до појаве прертасподјеле напона и његове концентрације у појединим правцима и тачкама, односно долази до појаве пластичних деформација које су праћене ломљењем стијенске масе и кретањима материјала према откопаном простору...
    модел, метод коначних елемената, просторија отварања, напон, дефеормација стијенског масива, алгоритам функционалних зависности

  • 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 ...

  • 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

  • Mineralogical analysis of a clay body from Zlakusa, Serbia, used in the manufacture of traditional pottery

    Maja Milošević, Biljana Đorđević, Mihovil Logar (2020)
    калцит, сирова глина, традиционална керамика, Злакуса
    ... it for the next 24h. As the excess water is drained, the clay body is extracted onto a table, which will allow for its further prepar- ation and for the addition of calcite. The calcite pieces are first hammered to obtain smaller pieces and then ground in a fine grinding hammer mill, and for the ...
    ... the size of the vessel to be made. For example, for larger pots, such as celebration or wedding pots, the recipe involves 60% calcite and 40% clay (Djordjević, 2013). The next step is to mix the clay and calcite powder into a homogeneous mass that is ready for processing. From there, a piece of clay ...
    ... Table 3. Samples with PI <10% are not appropriate for the manu- facture of building-related items, and those with a PI >34% would be difficult to extrude (Barnes, 2014). The LL values for CIMx (55.2%) and ClBd (32.4%) are within the range defined for applica- tion in the manufacture of ceramics (30-60%) ...

  • Mechanosynthesis and structural characterization of nanocrystalline Ce1–Y O2– (x=0.1–0.35) solid solutions

    Martin Fabián, Bratislav Antić, Vladimír Girman, Milica Vučinić-Vasić, Aleksandar Kremenović, Shigeru Suzuki, Horst Hahn, Vladimír Šepelák (2015)
    A series of nanostructuredfluorite-type Ce1–xYxO2–δ (0rxr0.35) solid solutions, prepared via highenergy milling of the CeO2/Y2O3mixtures, are investigated by XRD, HR-TEM, EDS and Raman spectroscopy. For thefirst time, complementary information on both the long-range and short-range structural features of mechanosynthesized Ce1–xYxO2–δ, obtained by Rietveld analysis of XRD data and Raman spectroscopy, is provided. The lattice parameters of the as-prepared solid solutions decrease with increasing yttrium content. Rietveld refinements of the XRD data reveal increase in microstrains in the host ceria ...
    Ceria, Yttrium, Solid solution, Mechanosynthesis, Oxygen vacancy, Nanocrystalline material

  • Study of the Synergetic Effect of Co-Pyrolysis of Lignite and High-Density Polyethylene Aiming to Improve Utilization of Low-Rank Coal

    Ivan Kojić, Achim Bechtel, Nikoleta Aleksić, Dragana Životić, Snežana Trifunović, Gordana Gajica, Ksenija Stojanović (2021)
    Polimeri i plastika, opšta hemija
    ... per minute is observed at 479.5 ◦C and 484.0 ◦C for the HDPE and lignite/HDPE mixture, respectively. The residual mass at 500 ◦C for lignite alone was 75%, and for HDPE alone was 4.79%, based on which the expected percentage of undecomposed residue for a mixture of lignite and HDPE (1:1) according to ...
    ... 40:1). The suspension was intensively shaken and left in a dark place for 16 h. The suspension was then refluxed for 20 min and filtered to separate asphaltenes. Asphaltene precipitate was rinsed several times with hot n-heptane for total removal of maltenes (n-heptane soluble fraction). Excess of n-heptane ...
    ... and their mixture) into liquid and gaseous products. However, the increase is much more prominent for HDPE and the lignite/HDPE mixture than for lignite alone. The greatest yield of liquid products for all three substrates is recorded at 500 ◦C, suggesting that, at higher temperatures, their further ...

  • Geotechnical conditions of “Debelo brdo” tunnel construction on the highway E-80: Nis-Merdare-Pristina (“Peace Highway”)

    Dragoslav Rakić, Irena Basarić Ikodinović, Radojica Lapčević, Dragan Lukić (2024)
    The construction of the highway E-80 has begun in Serbia, which will represent the traffic hub of the Western Balkans and will be part of the main regional transport network of Southeast Europe. Its total length through Serbia is 77 km, and one part of the route is designed through a typical plain terrain, while a larger part of the route passes through hilly terrain. The construction of the tunnel “Debelo brdo” is planned partly in an open cut ...
    „Debelo brdo“ tunnel, temporary slopes, open cut excavation, tunnel excavation, piles

  • The influence of Al<sup>3+</sup>ion on porcine pepsin activity<i>in vitro</i>

    Vesna M. Pavelkić, Kristina R. Gopcević, Danijela Z. Krstić, Marija A. Ilić (2008)
    The in vitro effect of Al3þ ions in the concentration range 1.7·1026M–8.7·1023M on pepsin activity at pH 2, via kinetic parameters and its electrophoretic mobility was evaluated. Kinetic study demonstrated the existence of an activation effect of Al3þ at pH 2 on pepsin molecule. Kinetic analysis with respect to concentrations of haemoglobin showed that Al3þ ions increase the maximal velocity (Vmax) and kcat values rather than apparent affinity for substrate (KS) implying the non-competitive nature of activation which indicated ...
    Пепсин, алуминијум, кинетика, активација, електрофоретска мобилност
    ... are used for calculating equilibrium constants K,s and K,A for dissociation of formed binary enzyme-activator (AP' ) and ternary enzyme- activator-substrate complexes (Figure 3, Scheme 1). The calculated values for constants are 0.904 + 0.083 mM and 8.56 + 0.51 kM, respectively. For further ...
    ... respect- ively. Other constants, K,A = 8.56 + 0.51 M for binding of aluminium to pepsin-haemoglobin com- plex and Kws = 0.904 0.76 + 0.083mM for binding of haemoglobin to pepsin-aluminium complex are in agreement with proposed conditions for partially non- competitive activation mechanism. ...
    ... a. values rather than apparent affinity for substrate (Ks) implying the non-competitive nature of activation which indicated that aluminium wWas a non-essential activator of partial non-competitive type. The values of the equilibrium constants Ks and KA for dissociation of corresponding complexes ...

  • Simpson's rule application for experimental determining parameters of rock mass oscillation equation at limestone

    Suzana Lutovac, Miloš Gligorić, Jelena Majstorović, Branko Gluščević, Luka Crnogorac (2021)
    By its form, the use of explosives has a destructive character. However, energy of chemical explosives is tamed and perfected in many effects, so that is developed a series of activities which work is unthinkable without the use of explosives. In mining industry, explosives are most commonly used for exploitation in hard rock mass. Thereby, large amounts of explosives can be used, especially for mass blasting. The application of large amounts of explosives gives auspicious techno – economic indicators ...
    working environment, seismic effects of blasting, oscillation velocity, rock mass oscillation equation, Simpson’s rule

  • Flotability of chalcopyrite from the Rudnik deposit

    Đurica Nikšić, Predrag Lazić, Milena Kostović (2021)
    Директно селективно флотирање олова, бакра и цинка у флотацији рудника „Рудник” датира од 1984. године. Технолошка шема омогућава директно издвајање селективних концентрата у три циклуса. У првом циклусу се издваја минерал олова (галенит), док су минерал бакра (халкопирит) и минерал цинка (марматит) депримирани. У другом циклусу се оток концентрације минерала олова кондиционира и припрема за издвајање минерала бакра. Након кондиционирања, у овом циклусу се издваја минерал бакра. У трећем циклусу се оток концентрације минерала бакра кондиционира и припрема за ...
    Директно селективно флотирање, халкопирит, KAX, NaCN

  • Optimization and Analysis of Drilling and Blasting Parameters Using O-Pitblast Software

    Stefan Milanović, Nikola Simić, Lazar Kričak, Milanka Negovanović, Nikola Đokić (2024)
    The development of modern technologies has enabled the application of specialized softwares in the field of mining through various segments and processes, including in works related to drilling and blasting. The application of specialized software for drilling and blasting with the use of modern technologies such as photogrammetry enabled more accurate data from the field for later processing. By processing data and creating a 3D model of the terrain for drilling and blasting works, it can obtain precise data, ...
    optimizacija, 3D model, bušenje, miniranje, O-Pitblast, softver

  • Substitution reactions of some novel sterically hindered monofunctional Pd(II) complexes

    Aleksandar Mijatović, Jovana Bogojeski, Biljana Petrović, Živadin D. Bugarčić (2011)
    Reakcije supstitucije monofunkcionalnih kompleksa [(TLtBu)PdCl]+ i [Pd(tpdm)Cl]+, gde je TLtBu = 2,6-bis[(1,3-di-terc-butilimidazolin-2-imino)metil]piridin i tpdm = terpiridindimetan, sa nukleofilima kao što su: tiourea, I−, Br−, NO2−, piridin i dimetil-sulfoksid (DMSO) proučavani su u 0,1 M vodenom rastvoru NaClO4 u prisustvu 10 mM NaCl. Reakcije su sprovedene na tri različite temperature (288, 298 i 308 K) korišćenjem tehnike zaustavljenog protoka na različitim temperaturama. Reakcije supstitucije su praćene pod uslovima pseudo prvog reda sa velikim viškom nukleofila. Dobijeni rezultati pokazuju da kompleks ...
    Materials Chemistry, Inorganic Chemistry, Physical and Theoretical Chemistry
    ... these complexes are novel, for better understanding of their characteristics we compared the rate con- stants for the substitution reactions with I� with earlier published values for some other sterically crowded monofunctional Pd(II) complexes, Table 2. According to the values for the second-order rate constant ...
    ... spontaneous hydrolysis of the complexes. The temperature dependence of the second-order rate con- stants was studied for the reactions of [(TLtBu)PdCl]+ complex with I� and pyridine and for the [Pd(tpdm)Cl]+ complex with I�, Br�, pyridine and DMSO. The observed pseudo-first-order rate constants, kobs, ...
    ... spontaneous hydrolysis of the complexes. The temperature dependence of the second-order rate con- stants was studied for the reactions of [(TL®")PdCl]* complex with I- and pyridine and for the [Pd(tpdm)Cl]* complex with I-, Br-, pyridine and DMSO. The observed pseudo-first-order rate constants, kops, were ...

  • Modern self-propelled surface drill rigs for drilling small diameter holes in mining and construction operations

    Milanka Negovanović, Lazar Kričak (2021)
    Приликом одређених рударских или грађевинских радова потребно је извршити минирање применом бушотина малог пречника. Раније, бушење бушотина малих пречника се изводило углавном ручним бушилицама или лаким лафетним бушилицама нa одређеним нoсачима. Проблеми у овим случајевима били су капацитет бушења, бушење већих дужина бушотина и посебно безбедност оператера на неприступачним теренима, где је његово присуство било неопходно. Данас постоје модерне самоходне бушилице за бушење минских бушотина малог пречника, које су у потпуности даљински управљане. Радио даљинска контрола омогућава да се ...
    Бушилице,бушотине малог пречника, бушење, минирање,изградња,минирање негабарита, радио даљинска контрола

  • Evidence for Badenian marine transgression in Belgrade (Serbia)

    Filip Anđelković, Dejan Radivojević (2019)
    ... Измењено: 2023-10-14 04:22:14 Evidence for Badenian marine transgression in Belgrade (Serbia) Filip Anđelković, Dejan Radivojević Дигитални репозиторијум Рударско-геолошког факултета Универзитета у Београду [ДР РГФ] Evidence for Badenian marine transgression in Belgrade (Serbia) | ...
    ... The severing of connections with the Mediterranean is the cause for the partial isolation and fall of salinity (Rögl, 1999). REFERENCES Anđelković, M. 1987. Geology of the wider Belgrade area – Geology and geodynamics. Institute for regional geology and palaeontology, Faculty of Mining and Geology ...
    ... faculty publications available in open access, as well as the employees' publications. - The Repository is available at: www.dr.rgf.bg.ac.rs Evidence for Badenian marine transgression in Belgrade (Serbia) Filip Anđelković1 and Dejan Radivojević1 1University of Belgrade, Faculty of Mining and Geology ...