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Упит dcterms_subject_txt:limit ratio

226 items

  • Production of electricity from coal-fired power plants and accompanying CO2 emissions: comparison of EU-27 and US

    Uroš Djorgovski, Aleksandar Madžarević, Predrag Jovančić (2023)
    Even in the third decade of the 21st century, large power plants are still responsible for more than half of the electricity production in Europe and US. They predominantly use fossil fuels in their work, which results in the emission of pollutants into the air, soil and water. In addition to the production of electric energy, fossil fuels, including coal, are used for industrial purposes. Although the use of coal, especially in the countries of the European Union, is ...
    CO2, емисија, угаљ, термоелектрана, САД, ЕУ-27
    ... largest thermal power plants in the EU-27 and the US in 2021 [13, 14, 15] Power plant Countr: State/ emics(s)iž)ns Coal / Fuel lnsolalšd Ratio Generation Ratio Wer p MM | - Province ŠOs ii p [ICO2/MW] |_ [MWh] | |[tCO2/GWh] IMt] [MW]| Belchatow Poland | \VOjew0dZtWO | -25540 Lignite 5097 5,01 27400 ...
    ... one of the largest emitters of CO> in Europe Table 3. CO;» emissions from coal-fired power plants in 2021 [11] Million | Ratio to the area of IRatio to th bel Ratio to electricity | Ratioto electricity | Ratioto electricity Ratioto GDP tons the territory i:hl:bi(l)anle% F\uan) /23 production ...
    ... an obvious connection between the level of development of a country or region and the amount of energy consumed in the country. Figure 3 shows the ratio of specific electricity production per capita in the EU-27 and the US. In the last 2 decades, the ! Minor amounts of coal are still consumed in ...

  • Phase relations and physical indicators of municipal waste from old landfills in Serbia

    Dragoslav R Rakić, Irena G Basarić Ikodinović, Jovana M Janković, Tina D Đurić (2021)
    Due to certain similarities of municipal waste and soil, usually for the determination of basic parameters of physical state, laboratory and field tests which are common in geotechnical investigations are used. It is often to construct an apparatus for special purpose to perform some specific laboratory and field tests. Therefore, different values of indicators of municipal waste physical state can be found in the literature. The basic reasons should be found in different definitions and methods that researchers use ...
    municipal waste, moisture content, unit weight, specific gravity, grain size distribution, porosityGeneral Computer Science
    ... particles (ys). The most common parameters are: dry unit weight (ya) expressed by weight-volume ratio - W„/V; porosity (n) expressed by volume ratio - V,/V and moisture content (w) expressed by weight ratio - W„/W.. All three parameters are defined by weight — W (or mass – m) and volume — V (Table ...
    ... important physical parameters of municipal waste (Fassett et al., 1994). Parameter Mark Unit Relations Unit weight Y kN/m) Y=W/V=(I+w) ·Ya Void ratio e mš/m* e= V /V, = | ___I-n Unit weight W a of solid A kN/m* E i ——— particles Vs 1-n 'Volume water v m*/m* v= V Zw.J0 content -% V Yw Volume ...
    ... contacts between them dry and other way around. Therefore, only porosity between particles was analysed in this paper. For the determination of void ratio, artificially prepared samples for testing of shear strength and compressibility of municipal waste (44 samples in total) were used. They were ...

  • Molecular and Isotope Composition of Biomarkers in Immature Oil Shale and its Liquid Pyrolysis Products (Open and Closed System)

    Gordana Gajica, Aleksandra Šajnovic, Jan Schwarzbauer, Aleksandar Kostić, Branimir Jovančićević, Ksenija Stojanović (2021)
    The molecular and isotopic composition of biomarkers in initial bitumen isolated from raw immature oil shale samples from the Lower Miocene Aleksinac Basin (Serbia) and liquid products (LPs) obtained by pyrolysis in open (OS) and closed systems (CS) are studied. The influence of pyrolysis type and variations of kerogen type on biomarkers composition and their isotopic signatures in LPs is determined. The molecular composition of the LPs from the OS pyrolysis is very similar to those in initial bitumen, independently ...

  • Geochemical characterization of sediments from the archaeological site Vinča – Belo Brdo, Serbia

    Gorica Veselinović, Dragana Životić, Kristina Penezić, Milica Kašanin-Grubin, Nevenka Mijatović, Jovana Malbašić, Aleksandra Šajnović (2020)
    Earth-Surface Processes
    ... sample V4 (Table 4). To qualitatively explore the relative input of terrestrial to aquatic OM, the ratio of higher plant n-alkanes to aquatic n-alkanes was measured using the terrestrial to aquatic ratio (TAR) following Bourbonniere and Meyers (1996). The highest TAR value is noticed for samples V6 and ...
    ... 97 and 0.87; Table 4). A proxy ratio L/H (low to high n-alkanes) is calculated ac- cording Li et al. (2016), which reflects the relative contribution of microorganisms compared to terrestrial plants. L/H values are varying from 0.25 in sample V6 to 1.43 in V10. The ratio of long chain n-alkanes to short ...
    ... 2001; Li et al., 2016). Values of the ratio of n-C27/n-C31 throughout the test profile are in the range of 0.58 for V3 to 3.14 for sample V6, and the values of the n-C29/n-C31 parameter are in the range 0.87 for V3 to 3.65 for V4 (Table 4, Fig. 7). A proxy ratio, Paq, has been calculated according to ...

  • Overcoming the Low Oral Bioavailability of Deuterated Pyrazoloquinolinone Ligand DK-I-60-3 by Nanonization: A Knowledge-Based Approach

    Jelena R. Mitrović , Branka Divović-Matović, Daniel E. Knutson, Jelena B. Ðoković, Aleksandar Kremenović, Vladimir D. Dobričić, Danijela V. Randjelović, Ivana Pantelić, James M. Cook, Miroslav M. Savić, Snežana D. Savić (2021)
    Poor water solubility of new chemical entities is considered as one of the main obstacles in drug development, as it usually leads to low bioavailability after administration. To overcome these problems, the selection of the appropriate formulation technology needs to be based on the physicochemical properties of the drug and introduced in the early stages of drug research. One example of the new potential drug substance with poor solubility is DK-I-60-3, deuterated pyrazoloquinolinone, designed for the treatment of various neuropsychiatric ...
    pyrazoloquinolinones, nanocrystals, wet media milling, fasted/fed bioavailability

  • Control of substructure construction of railways in the Republic of Serbia

    Dragan Lukić, Dragoslav Rakić, Irena Basarić Ikodinović (2022)
    Контрола збијености природног тла (у ископу) или збијеног у насипу при изградњи саобраћајница представља један од основних облика контроле квалитета доњег строја. Код изградње брзих саобраћајница (аутопутеви и брза железница) приоритет је постизање високог нивоа контроле извршених радова. У циљу онемогућавања диференцијалног слегања (при изградњи насипа), или промене запремине услед допунског збијања материјала, које неминовно доводе до деформација, потребно је извршити оптимално збијање материјала. У оквиру овог рада приказује се техничка регулатива која регулише контролу збијености при изградњи железничке ...
    доњи строј, техничка регулатива, насип, збијеност, контрола
    ... the construction and improvement of tracks on local railways and secondary tracks on all railways Ev2 > 80 MN/m2, Ev2/ > 40 MN/m2, Rc* where the ratio Ev2/ Ev1 less than the minimum value prescribed for Ev2. The protective layer as a filter must have water permeability, and the flow rate cannot be ...
    ... Ev2/Ev1 m2, Rc* for the construction and improvement of tracks on local railways and secondary tracks on all railways Ev2 > 45 MN/m2 m2, Rc* where the ratio Ev2/ Ev1 less than the minimum value prescribed for Ev2. When creating a transition layer, the following is used: capillary rise resistant material; ...
    ... > 2.0 m Ev2 > 20 MN/m2, Ev2/Ev1 2.2, Evd > 20 MN/m2 or Rc* > 95%; for railways in the cut Ev2 > 45 MN/m2, Ev2/ > 25 MN/m2 or Rc* > 95% where the ratio Ev2/ smaller than the minimum value prescribed for Ev2. The load-bearing capacity of the embankment layers, except for the load-bearing capacity at ...

  • Extreme Rainfall Event and Its Aftermath Analysis—IPL 210 Project Progress Report

    Biljana Abolmasov, Mileva Samardžić Petrović, Ranka Stanković, Miloš Marjanović, Jelka Krušić, Uroš Đurić (2021)
    Landslides, Extreme precipitation, Data analysis, IPL project report
    ... regions in Serbia both affected by same extreme rainfall event in May 2014. In both regions dominant type of movement was sliding, but with different ratio between debris and soil as material involved. The analysis showed that there are no significant differences between first activated and reactivated ...
    ... was that differences in soil saturation caused by high antecedent precipitation and then intensive precipitation during 72 h could condition the ratio between first activated and reacti- vated landslides. Results and Discussion According to the rainfall data analysis, it is obvious that Western ...
    ... the Western Serbia dominant type of material was debris (59%) whereas in Central Serbia was soil (71%) for slides for instance (Fig. 4). A similar ratio could be found in overall types of movement versus types of material involved analysis by region. Basic geological and engineering geological data ...

  • Maturation and isotopic changes of individual hydrocarbons in lignite lithotypes through diagenesis and early catagenesis

    Ivan Kojić, Achim Bechtel, Reinhard Sachsenhofer, Dragana Životić, Ksenija Stojanović (2019)

  • 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
    ... to the high ash con- tent. The upper limit of the oxygen bound in the inorganic components can be calculated as an approximate value from the difference of X,i and Yox calculated from the corresponding oxides of X (Table 4). The corresponding O/C molar ratio excluding the maximum oxygen in the ...
    ... resulting O/C ratio is much closer to the value found by element analysis (0.06). The results for the relative fraction of different types of CO functional groups obtained by C1s and O1s are in fair agree- ment. The ratio of C-O and C = O from O15s, denoted as Ro:s(CO) and the ratio of C-O groups ...
    ... 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 role for the properties of the chars considered in this paper. Sulphur was above the detection limit for AC1 and PW700g and will ...

  • The Potential of Biomarkers to Distinguish Lower and Middle Miocene Lignites from the Coal-Mining District of Lusatia

    I. Kojic, J. Kus, D. Zivotic, K. Stojanovic (2021)

  • Crystallography and Surface Oxidation of Stoichiometric Arsenopyrite from Šumadija-Kopaonik Pb-Zn/Polymetallic Ore District (Serbia)

    Ivana Jelić, Aleksandar Pačevski, Aleksandar Kremenović, Aleš Šoster, Andreja Šestan, Janez Zavašnik (2023)
    The behaviour and stability of arsenopyrite largely depend on its crystal structure, but studies of crystallography and structural defects are scarce. For clarification, we investigated a series of natural arsenopyrite crystals from the polymetallic Pb-Zn-(±Cu,Ag,Au,Sb,Bi,W) Šumadija-Kopaonik ore district (Serbia) by powder X-ray diffraction (XRPD). Among them, samples from the Drenjak gold mineralisation showed near-stoichiometric FeAsS composition and were further investigated by conventional and high-resolution transmission electron microscopy methods. TEM revealed abundant planar crystallographic defects and epitaxial surface oxide layer ...
    Inorganic Chemistry, Condensed Matter Physics,General Materials Science, General Chemical Engineering, crystal structure, FeAsS, oxidation, TEM, XRPD
    ... diffraction measurements, especially for fine-powdered samples with a large surface-to-volume ratio [28]. Assuming, the spherical shape of the particles and the observed speed of oxide formation, the detection limit of ~1% by volume criterion for a 5 nm thick surface oxide layer formed upon ~10 min air ...
    ... composition, i.e., As:S ratio. The calculated arsenic content is close to its theoretical value of 33.3 at.%; therefore, it can be said that the examined arsenopyrite from Drenjak shows almost ideal stoichiometry. Crystals 2023, 13, 278 5of1l1l 100 nm Otherwise, the As:S ratio in arsenopyrite can ...
    ... TEM chamber by energy-dispersive X-ray spectroscopy (EDS). The quantification was assessed by the Cliff-Lorimer ratio thin section method (four iterations), with the Si-K line as the ratio standard element and line [20]. The calculated composition, mean of 16 spot analyses, was determined as (wt%): ...

  • Hydrochemical features and their controlling factors in the Kucaj-Beljanica Massif, Serbia

    Fen Huang, Ljiljana Vasic, Xia Wu, Jianhua Cao, Saša Milanovic (2019)
    Earth-Surface Processes, Geology, Pollution, Soil Science, Water Science and Technology, Environmental Chemistry, Global and Planetary Change

  • Application of Lignite Combustion Waste Slag Generated in Heating Plants as a Partial Replacement for Cement. Part II: Physical–Mechanical and Physical–Chemical Characterization of Mortar and Concrete

    Milan Kragović, Nenad Ristić , Jelena Gulicovski, Andrijana Nedeljković, Snežana Pašalić, Ivica Ristović, Marija Stojmenović (2021)
    sagorevanje lignita, otpadna šljaka, zamena cementa, proizvodnja maltera i betona, fizičko-mehanička i fizičko-hemijska karakterizacija

  • The number of unimodular roots of some reciprocal polynomials

    Dragan Stankov (2020)
    We introduce a sequence P2n of monic reciprocal polynomials with integer coefficients having the central coefficients fixed. We prove that the ratio between number of nonunimodular roots of P2n and its degree d has a limit when d tends to infinity. We present an algorithm for calculation the limit and a numerical method for its approximation. If P2n is the sum of a fixed number of monomials we determine the central coefficients such that the ratio has the minimal limit. ...
    Algebraic integer, the house of algebraic integer, maximal modulus, reciprocal polynomial, primitive polynomial, Schinzel-Zassenhaus conjecture, Mahler measure, method of least squares, cyclotomic polynomials
    ... we determine the central coefficients such that the ratio has the minimal limit. We generalise the limit of the ratio for multivariate polynomials. Some examples suggest a theorem for polynomials in two variables which is analogous to Boyd’s limit formula for Mahler measure. Résumé. Nous introduisons ...
    ... integer coefficients having the central coefficients fixed. We prove that the ratio between number of nonunimodular roots of P2n and its degree d has a limit when d tends to infinity. We present an algorithm for calculation the limit and a numerical method for its approximation. If P2n is the sum of a fixed ...
    ... be the ratio between the number of nonunimodular zeros of P and its degree. Actually, it is the probability that a randomly chosen zero is not unimodular, and C(P) = Ee) We are looking for the sequence P2,, of monic reciprocal polynomials with integer coefficients, such that C(P2,) has a limit when n ...

  • Projection of SO2 emissions in coal power plants in Serbia

    Aleksandar Madžarević, Predrag Jovančić, Stevan Đenadić, Filip Miletić, Miodrag Ristović, Miroslav Crnogorac (2023)
    The production of electricity in the countries of South-Eastern Europe (SEE) was mainly related to the use of coal, predominantly lignite. The total installed capacity of thermal power plants using coal in these seven countries is 17.813 MW, distributed in 31 thermoblocks. The mentioned plants are the dominant pollutant emitters in all observed countries. Data on the largest emitters in the countries of the European Union and a comparison with SEE countries were collected. The calculation of emissions of ...
    енергeтика, емисије, СО2, угаљ, електране
    ... Poland and Serbia [5, 11} Emissions Parameter Amount of emission [tons] 279200 102470 Ratio to the area of the territory [SO>»/km-] 3,15 0,33 Ratio to the number of inhabitants [kgSOyx/st] 40,88 1,23 Ratio to electricity production [keSOx/MWh] 11,63 0,70 3. PROJECTION OF SO; EMISSIONS By studying ...
    ... amount of SO» produced in the amount of 86424 t, an average of 16759 t of SO» should go into the atmosphere. This value represents the permissible limit. 4. CONCLUSION Air pollution from coal-fired thermal power plants knows no national borders. Through the paper, it was pointed out that the area ...

  • Karst aquifer impact on the formation of surface runoff: case study of the Resava River catchment, Serbia

    Marina Mitrašinović, Vesna Ristić Vakanjac, Veljko Marinović, Saša Milanović, Ljiljana Vasić, Dušan Polomčić (2022)
    The paper compares the flow regimes of the Resava River at the gauging stations of the Manasija Monastery (upper course) and the town of Svilajnac (lower course). The hydrological analysis encompasses a multiyear period of monitoring (1982–2020). The water budget and baseflow index are assessed for the catchment areas monitored by the Svilajnac station (683 km2) and the Manasija Monastery station (358k m2), considering the overall monitoring period and characteristic years. The results indicate that the specific runoff in ...
    hydrogeological characteristics, water regime, water balance, karst aquifer, Resava catchment area
    ... discharge 256 equal to the multiyear average, to 0.965 in the dry year. The hydrographs show that the ratio of mcean annual discharges is 1:1.25 (2001) and even lower in 2018 (1:1.15). The ratio of the catchment areas covered by the gauging stations is 1:1.75. This sug- gests that most of the discharge ...
    ... discharge of the Resava River is formed in the upper catchment (Figs. 1a,b). In the case of the characteristic low mean annual dis- charge, thc ratio was 1:0.57 in 1994, meaning that during dry periods the annual discharges are lower at the downstream station than thc upstream sta- tion. This can ...

  • Clayed wastewater treatment

    Dušica Vučinić, Đurica Nikšić, Predrag Lazić (2019)
    Анионски (A120), нејонски (N100), катјонски (C460; C581) флокуланти и коагулант Al₂(SO₄)₃ коришћени су за пречишћавање отпадних вода са садржајем глине. pH дисперзије је износио 7,8, са концентрацијом чврстих материја од 25,93 kg/m³ (глина и кварц). 54% чврстих честица имало је пречник мањи од 10 μm. Брзина таложења без примене флокуланата износила је 0,4 m/h. Ефикасност коришћених флокуланата је следећа: A120 >> N100 >> C460. У присуству A120 (100 g/t) брзина таложења достигла је око 25 m/h, а добијен ...
    отпадне воде, глине, флокулација, зета потенцијал

  • A comparative study of the molecular and isotopic composition of biomarkers in immature oil shale (Aleksinac deposit, Serbia) and its liquid pyrolysis products (open and closed systems)

    Gordana Gajica, Aleksandra Šajnović, Ksenija Stojanović, Jan Schwarzbauer, Aleksandar Kostić, Branimir Jovančićević (2021)
    The molecular and isotopic composition of biomarkers in initial bitumen isolated from immature (0.41% Rr) oil shale samples (Aleksinac deposit) and liquid products obtained by pyrolysis in open (OS) and closed (CS) systems are studied. The influence of pyrolysis type and variations of kerogen type on biomarkers composition and their isotopic signatures in liquid products is determined. The applicability of pyrolysis type, numerous biomarkers and carbon isotopic compositions (δ13C) of n-alkanes in liquid pyrolysates is established. Pyrolysis experiments were ...
    Uljni šejl, Aleksinac, organska supstanca, otvoreni i zatvoreni sistem pirolize, biomarkeri, izotopski sastav ugljjenika
    ... velocity was set to 35 cm s−1. The oxidation oven equipped with a CuO/ NiO/Pt-catalyst was set at 940 ◦C. Each isotope ratio determination was run in triplicate. The carbon isotope ratio of the reference gas (carbon dioxide) was calibrated with a certified reference standard purchased from Chiron (Trondheim ...
    ... In initial bitumen of both raw samples, the uniform Pr/Ph ratio <0.4 indicates sedimentation under reducing depositional conditions, which enhanced the preservation of algal-rich OM (Table 1; Gajica et al., 2017a). The values of Pr/Ph ratio are higher in all liquid pyrolysates than in initial bitumen ...
    ... (Sert et al., 2009). In addition to the high content of solid fossil hydrocarbons (HCs), a significant feature of oil shales is the high atomic H/C ratio (coal 0.4–1.0; oil shales >1.7; oil ~1.9) and unique composition of organic matter (OM) in relation to other solid fossil fuels (Strizhakova and Usova ...

  • 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 ...

  • 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