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Упит dcterms_subject_txt:mathematical content

477 items

  • Application of stochastic models for mine planning and coal quality control

    Dejan Stevanović, Božo Kolonja, Ranka Stanković, Dinko Knežević, Mirjana Banković (2014)
    ... n process in stockpiles throughout the mine's life. Sulfur content is treated as lognormally distributed random variable. The objec- tives of the model include minimizing the expected sulfur content and standard de- viation in sulfur content. The methodology was illustrated using the case study on Kolubara ...
    ... mine some parts of deposit with high con- tent of organic sulfur, over 2% (see fig. 7). Ad- justed on share of 95 percentiles content of sul- fur is over 1%, althought content in most of parts of the deposit is under 0.4%. The space distribution of sulfur required the homogeniza- tion of coal according ...
    ... proposed a methodology to generate equally probable models based on maps of sulfur content within a coal deposit in Kolubara surface mine. These models allow assessing the uncertainty associated with the grade content in the ROM coal supplied to the power plant. As the size (mass) of the pile in- creased ...

  • Određivanje zbijenosti starog komunalnog otpada

    Jovana Janković, Dragoslav Rakić, Irena Basarić Ikodinović, Tina Đurić (2021)
    Bez obzira na savremene tretmane komunalnog otpada u svetu, u Srbiji je i dalje najčešći vid odlaganja na komunalne deponije, pa zbijanje otpada predstavlja jednu od ključnih faza formiranja deponije. Na ovaj način znatno se smanjuje zapremina otpada, ubrzava proces degradacije i produžava radni vek deponije. Zbog toga su geotehničke karakteristike komunalnog otpada prilikom zbijanja, veoma bitne kako u fazi projektovanja tako i u fazi izgradnje deponije i optimizacije prostora. Tu se pre svega misli na maksimalnu suvu zapreminsku ...
    komunalni otpad, deponija, Proktorov opit, optimalna vlažnost, maksimalna suva zapreminska težina

  • Magmatic pulses during Mediterranean-style continental collisions: A numerical modelling approach

    Nevena Andrić, Katharina Vogt, Liviu Matenco, Vladica Cvetković, Sierd Cloetingh, Taras Gerya (2017)

  • Building learning capacity by blending different sources of knowledge

    Ivan Obradović, Ranka Stanković, Olivera Kitanović, Dalibor Vorkapić (2016)
    ... the initial institutions involved, it is expected that this network will also attract a wider range of universities and enterprises to offer OER content within additional network nodes, which they would develop within their own institutions. In view of such a development, the BAEKTEL network features ...
    ... attract students and staff from other parts of the world. In this context, transparency will be increased by offering an insight in the academic content published by different academic institutions, helping prospective students to make their choice of the university that best suits their needs. ...
    ... features a web application for management, browse and search of metadata, but also web services for terminological and linguistic support. Since OER content within the network can be published in different languages, the web application and web services support network multilinguality. Other various ...

  • Sustainable development in oil sector of the Republic of Serbia

    Karović Maričić Vesna, Leković Branko, Danilović Dušan (2017)

  • Surface functional groups and degree of carbonization of selected chars from different processes and feedstock

    Marija Ilić, Franz-Hubert Haegel, Aleksandar Lolić, Zoran Nedić, Tomislav Tosti, Ivana Sredović Ignjatović, Andreas Linden, Nicolai D. Jablonowski, Heinrich Hartmann (2022)
    The knowledge ofthe structural and chemical properties of biochars is decisive for their application as technical products. For this reason, methods for the characterization of biochars that are generally applicable and allow quality control are highly desired. Several methods that have shown potential in other studies were used to investigate two activated carbons and seven biochars from different processes and feedstock. The chars were chosen to cover a wide range of chemical composition and structural properties as a hardness ...
    Biougalj, različiti procesi dobijanja, različite sirovine, površinski aktivne grupe, x-ray, FT-IR,XPS
    ... found for HW500f, which has also high ash content, with 104.9 + 1.4% for the sum of all deter- mined elements. The nitrogen content was below the detection limit for most of the chars and generally more than one order of magnitude lower than the oxygen content. Therefore, it does not play an important ...
    ... The pyrochars made at lower temperature release less ions corre- sponding to low ash content in SW500f as well as in BW550 and the dominant content of SIO> in the ash of HW500f. The leachate of ACI with high content of Al and Si has a particularly low EC value. The UV absorbance of acidified NaOH ...
    ... ash-rich HW500f resulting in an O/C ratio similar to SW500f. The largest relative standard deviations for the oxygen content were found for the biochars with the largest ash content HW500f (18.1%) and PW700g (19.4%). This might be an indica- tion that the ash components are inhomogeneousily distributed ...

  • Microemulsion with aromatic oil as cleaner media for electropolymerisation

    M. Ilić, F.-H. Haegel, S. Zlatanovic, N. Potkonjak, B. Simonovic (2005)
    Abstract Microemulsion polymerization is widely used as a cleaner alternative way to prepare intrinsically conductive polymers. We studied isothermal phase diagrams for microemulsions of the electropolymerizable heterocyclic aromatic oil 3,4-ethylenedioxythiophene (EDOT), aqueous LiClO4 solution and alkyl polyethoxylate. Our specific goal was to assess the effect of LiClO4 salt on the phase behaviour. The phase behaviour was characterized by stepwise titration and microscopic analyses. Here we found that the increase of the concentration of LiClO4 salt shifts the microemulsion region ...
    Микроемулзија, понашање фаза, EDOT, LiClO4

  • Influence of paleoenvironmental conditions on distribution and relative abundance of saturated and aromatic hydrocarbons in sediments from the NW part of the Toplica basin, Serbia

    Nikola Burazer, Aleksandra Šajnović, Nebojša Vasić, Milica Kašanin-Grubin, Dragana Životić, João Graciano Mendonça Filho, Predrag Vulić, Branimir Jovančićević (2020)
    Stratigraphy,Economic Geology,Geology,Geophysics,Oceanography

  • Development of Open Educational Resources (OER) for Natural Language Processing

    Cvetana Krstev, Biljana Lazić, Ranka Stanković, Giovanni Schiuma, Miladin Kotorčević (2015)
    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 ...
    E-Learning, Open Educational Resources, Computational Linguistics, Lexical Resources, edX
    ... The content of e-dictionaries for Serbian is given in more details. 4. The simple methods of pattern matching are presented. They are based on queries in the form of regular expressions whose basic elements are either word forms (strings) or lexical masks that refer to the content of e- ...
    ... three basic didactic criteria [15]:  adjusting the content to the target group,  systematization and gradualism in the teaching process,  connecting the theory and the practice. To satisfy the first criterion of adjusting the content to the target group, we provided a description of the ...
    ... its influence, and established the group of interested researchers. The first courses at University of Belgrade were introduced in 1994: in Mathematical and CL for students of General Linguistics and students of Serbian language at the Faculty of Philology, as well as NLP graduate courses for ...

  • Characterization of Natural Clay from Bogovina (Serbia) and Possible Utilization in Sorption of the Herbicides

    Lazar Kaluđerović, Zorica Tomić, Rada Đurović-Pejčev, Maja Milošević (2021)
    ... coefficients showed an increment in S-metolachlor sorption with increasing the content of the organic complex used in the montmorillonite modification. Positive relationship between the parameter Kf and the content of the organic complex was found. A general trend of sorption can ...
    ... Serbia Presentation Preference: Poster only Would you like to receive more information about applying for a grant once this becomes available?: Yes Content: The mineralogical composition of the soil clay fraction, along with soil organic matter, plays an important role in the sorption process of the soil ...

  • Maceralni sastav i rang uglja Ibarskog basena

    Željana Novković, Nevena Andrić -Tomašević, Vladimir Simić, Dragana Životić (2022)
    Donjemiocenski ugljonosni Ibarski basen se nalazi u južnoj Srbiji. Intramontanski ektenzivni basen, izdužen u pravcu severozapad-jugoistok ispunjen je slatkovodnim sedimentima koji su formirani kao deo Dinarskog neogenog jezerskog sistema. Paleoreljef basena izgrađen je od paleozojskih amfibolskih škriljaca, sericit-hloritskih škriljaca, krečnjaka, mermera i metabazičnih stena, mezozojskih peščara, laporca, laporovitih krečnjaka, krečnjaka, dolomita, ofiolita i oligo-/miocenskih magmatskih stena. Tercijarne magmatske stene izgrađene su od oligocenskih dacito-andezita i neogenih kvarctlatita/riodacita i piroklastičnih stena. Miocenski sedimenti izgrađeni su od aluvijalnih breča, konglomerata, peščara, ...
    ugalj, macerali, refleksija vitrinita, Ibarski basen

  • Geotehnički efekti razaranja komunalnog otpada različitim postupcima zbijanja

    Jovana M. Janković Pantić (2022)
    Odlaganje otpada na komunalne deponije predstavlja osnovni način zbrinjavanja otpada u Srbiji. Kako bi se prostor za deponovanje materijala racionalno koristio potrebno ga je svakodnevno zbijati sa unapred definisanom količinom vode koja se dodaje. Dobro zbijeni komunalni otpad zauzima manju zapreminu i omogućuje sigurnije skladištenje, pa je korisno prethodno laboratorijski odrediti parametre zbijanja: maksimalnu suvu zapreminsku težinu (dmax) i optimalnu vlažnost (wopt). U Srbiji do sada nisu određivani parametri zbijanja, dok je u svetu primenjivana standardna metoda (Proktorov opit) ...
    komunalna deponija, zbijanje, Proktorov opit, malj sa šiljcima, koeficijent razaranja

  • 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
    ... reaches 35%. The low degree of lignite degradation is in accordance with the low content of OM (total organic carbon of 29.77% and hydrogen of 2.79%; Section 3.3), as well as a high content of mineral matter (ash content of 47.12%), which is relatively stable and not subjected to significant decomposition ...
    ... carried out on lignite or bituminous coal having a low ash (4–12%, dry basis) and relatively high carbon content (62–84%, dry, ash-free bases) [33,35,36], not on low-quality lignite with a high ash content (>40%) and, consequently, a low calorific value (net calorific value <15 MJ/kg). Our preliminary test ...
    ... Therefore, the paper investigates lignite/HDPE co-pyrolysis as a possible method for utilization of lignite of extremely low quality (ash content > 40%; organic carbon content <30%). The objective was to examine and confirm the existence of a synergetic effect during low-quality lignite and HDPE co-pyrolysis ...

  • Korelacija magnetnog susceptibiliteta i sadržaja metala u flotacijskom jalovištu

    Filip Abramović, Vesna Cvetkov, Aco Ilić, Dragana Životić (2022)
    Procena metala u rudama, jalovištu i zemljištu se tradicionalno određuje hemijskim metodama kao što su Rengen fluorescentna analiza (XRF), Instrumentalna neutronska aktivaciona analiza (INAA) i Masena spektrometrija induktivno spregnute plazme (ICP-MS). Neke od pomenutih metoda su veoma zahtevne i skupe, te se nametnula potreba ka traženju jeftinijeg alata za brzu procenu prisustva pojedinih metala. Tokom poslednjih nekoliko decenija, mnoge studije su pokazale da su magnetna merenja dovoljno osetljiva da detektuju magnetni signal feromagnetnih materijala, a samim tim i metala ...
    flotacijsko jalovište, makroelementi, magnetna merenja

  • Knowledge Graphs in the Era of Large Language Models: Opportunities and Challenges

    Danka Jokić, Ranka Stanković, Jelena Jaćimović (2024)
    Pojava velikih jezičkih modela (eng. Large Language Models ili LLMs) je značajno uticala na oblast veštačke inteligencije, naročito u oblastima obrade prirodnog jezika i generisanju teksta. Međutim, ključno ograničenje ovih modela leži u nedostatku strukturiranog znanja i sposobnosti zaključivanja, što otežava njihovu primenu u stvarnom svetu, gde se zahteva tačnost iznetih činjenica i zaključivanje na osnovu konteksta. S druge strane, grafovi znanja nude primamljivo rešenje. Oni pružaju bogat izvor strukturiranog znanja, tako što predstavljaju entitete i njihove relacije u ...
    grafovi znanja, veliki jezički modeli, obrada prirodnog jezika, strukturirano znanje, kvalitet podataka, objašnjiva veštačka inteligencija, bezbednost sadržaja na internetu

  • Human Hemoglobin and Antipsychotics Clozapine, Ziprasidone and Sertindole: Friends or Foes?

    Lena Platanić Arizanović, Nikola Gligorijević, Ilija Cvijetić, Aleksandar Mijatović, Maja Krstić Ristivojević, Simeon Minić, Aleksandra Nikolić Kokić, Čedo Miljević, Milan Nikolić (2023)
    Packed with hemoglobin, an essential protein for oxygen transport, human erythrocytes are a suitable model system for testing the pleiotropic effects of lipophilic drugs. Our study investi gated the interaction between antipsychotic drugs clozapine, ziprasidone, sertindole, and human hemoglobin under simulated physiological conditions. Analysis of protein fluorescence quenching at different temperatures and data obtained from the van’t Hoff diagram and molecular docking indicate that the interactions are static and that the tetrameric human hemoglobin has one binding site for ...
    Inorganic Chemistry, Organic Chemistry, Physical and Theoretical Chemistry, Computer Science Applications, Spectroscopy, Molecular Biology, General Medicine, Catalysis

  • Fluid inclusion study in quartz of the Rudnik Pb-Zn-Cu-Ag skarn deposit, Serbia

    Stefan Petrović, Ronald J. Bakker, Vladica Cvetković, Rade Jelenković (2023)
    Six types of fluid inclusions were identified in three growth zones of hydrothermal quartz from the Rudnik skarn deposit. In the core zone, primary two-phase fluid inclusions of high (type 1) and moderate salinity (type 2) homogenized to liquid between 350-430 °C and 340-420 °C, respectively. Raman analysis revealed that the vapour phases are a CO2-CH4 gas mixture, with a predominance of CO2. The core contains and dispersed vapour-rich fluid inclusions of low salinity (type 3) composed of CO2-CH4-H2S ...

  • Coal homogenization stockyard sizing “Tamnava – Zapad” case study

    Božo Kolonja, Dinko Knežević, Ranka Stanković, Dejan Stevanović, Detlef Trummer (2016)
    ... the parameter of interest. Most often the parameters of interest are the lower heating value and sulphur content, but other parameters are also an option (iron or mercury content, ash content...) [Ignjatović et al. 2007]. When the anticipated quality range of the observed parameter is small, the ...
    ... quality of lignite extracted in Serbia is characterized by large variations in moisture and ash content, resulting in variations in lower heating value. The sulphur content is low, as is iron content, while mercury is monitored only sporadically. [Stevanović et al., 2015]. Thus the homogenization ...
    ... calculate, plan, control and predict the quality of ore being stacked and/or reclaimed with a great degree of accuracy. Robinson (2004) presents mathematical and computer models for the geometry of a stockpile, using both actual grade data and a variogram to describe the input variation. An application ...

  • Geochemical evaluation of dolostone deposits in Montenegro: Implications for potential industrial applications

    Darko Bozovic, Vladimir Simic, Dragan Radulovic, Slobodan Radusinovic, Vesna Matovic, Anja Terzic (2024)
    This study presents a unique model for assessing the dependability of continuous parts of combined systems in open-pit mining through the application of fuzzy logic. Continuous sub-systems as part of the combined system of coal exploitation in surface mines have the basic function of ensuring safe operation, high capacity with high reliability, and low costs. These subsystems are usually part of the thermal power plant’s coal supply system and ensure stable fuel supply. The model integrates various independent partial ...
    примарне сировине, минералогија, физичко-механичка својства, технолошка својства, наука о материјалима

  • FTIR Spectroscopic Study Of S-Metolachlor Sorption On Inorganic And Organically Modified Montmorillonite From Bogovina

    Lazar Kaluđerović, Zorica Tomić, Jelena Bogosavljević, Ljubomir Životić, Maja Milošević (2021)
    ... significantly with increasing concentration of HDTMA+ cation. All these changes are related to the decreasing of the water content in the interlayer space by increasing the content of HDTMA. The occurrence of the stretching CH2 vibrations is generally the main difference in the spectrum of HDTMA modified ...
    ... infrared spectroscopy. IR bands observed in the inorganic modified montmorillonite (Na-montmorillonite) are typical for smectites with a high Al content in the octahedron position. The intercalation of HDTMA+ cations into the interlayer space produces redshift of the IR bands that originate from ...