Претрага

Упит dcterms_subject_txt:chemical composition

313 items

  • 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

  • A fuzzy-based decision support model for effectiveness evaluation - a case study of examination of bulldozers

    Miloš Tanasijević, Predrag Jovančić, Dejan Ivezić, Uglješa Bugarić, Radiša Đurić (2019)
    Effectiveness evaluation is one of the basic components of engineering asset management and maintenance engineering in general. Effectiveness is an overall concept representing a measurement of quality of service level for the analyzed engineering system. This concept contains a series of partial indicators relating to time in operation and time for maintenance activities, as well as functional properties of the system. This article describes the analysis and structuring of partial indicators, as well as the development of a model ...
    Efikasnost, Fazi zaključivanje, Prikupljanje podataka, Buldozer

  • Cultural Heritage and Protection of Hand-Wheeled Pottery Manufacture in Western Serbia: Characteristics of Zlakusa Pottery Based on Sem-Eds and Optical Microscopy

    Milošević Maja, Zdravković Alena, Đordjević Biljana, Jelić Ivana (2021)
    ... close physical resemblance. The analysed samples of Zlakusa pots showed significant differences from the mineral composition, especially in the terms of elemental composition observed by EDS, to the distribution and appearance of pores concerning the manufacturing process. Further investigations ...
    ... sample 2 was made with the application of a modern mould technique. A microscopic examination of the thin sections revealed a uniform mineral composition. No significant differences were observed regarding the inner sections of the pots and their outer rims. Observed pores in sample 1 are of random ...

  • Structural dissymmetrization of optically anisotropic Grs64±1Adr36±1Sps2 grandite from Meka Presedla (Kopaonik Mt., Serbia)

    Pavle Tančić, Aleksandar Kremenović, Predrag Vulić (2019)
    In this paper, grandite core with Grs64±1Adr36±1Sps2composition was crystallographically studied. This core represents zone A of the macroscopically visiblefive A–E zones of the optically anisotropic Grs58–64 Adr36–42Sps2 grandite. The applied procedure includes the detailed analysis of the powder diffraction patterns, and the Rietveld refinements of the crystal structures in a series of 18 space groups and two mixtures, which were followed by the comparative analysis of the R-values, site occupancy factors, and the bond lengths and angles. Synthesis of all ...
    grandite, XRPD, crystal structure, structural dissymmetrization

  • Application of the Fuzzy Model in the Evaluation and Selection of Hydraulic Excavators on Open-Pit Lignite Mine

    Stevan Đenadić, Miloš Tanasijević, Vladimir Milisavljević, Dragan Ignjatović, Predrag Jovančić (2021)
    The production of lignite in large open-pit mines is mainly performed with continuously operating equipment, where bucket-wheel excavators, bucket-chain excavators, belt conveyors, and spreaders are the basic machines. Smaller machines, usually of discontinuous operating nature, are commonly categorized as auxiliary machines. This paper presents the research related to the analysis of auxiliary machine parameters with the case study for a hydraulic excavator. The purpose of the analysis was to develop a model of rating quality of service of the ...
    Fuzzy theory, hydraulic excavator, selection, quality of service, asset management

  • 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
    ... increase with increasing thermal maturity. However, the exact values that correspond to the oil window depend on the kerogen composition and other factors (Espitalié and COMPOSITION OF ORGANIC MATTER AND THERMAL MATURITY 5 taken from the black, layered, carbonaceous marls and shales that occur in a sequence ...
    ... Age Maceral composition Klobuk T L>V>I Župa T L>>V>I Necvijeće J I>L>V Avtovac J V>>L>I Bogdašići K Bit+Lam Pridvorci K Bit+Lam Todorići K Bit+Lam>>V+I M. Gruda K Bit Bugovina K Bit+Lam>>V+I Čepelica K Bit Kljen E V>>I>L Gacko M V>>I>L Table 3 Qualitative description of maceral composition at the ...
    ... Maceral composition at all localities analysed is given qualitatively in Table 3. Bitumen and framboidal py- rite were observed in all samples from Triassic to Eocene, but mostly in those from the Jurassic and Cretaceous sedi- mentary rocks. Table 3 Qualitative description of maceral composition at the ...

  • Trace elements and garnet formation in a distal skarn zone: a case study of the Rudnik deposit, Central Serbia

    Bojan Kostić, Pavle Tančić, Natalija Batoćanin (2024)
    geohemija granata, retke zemlje, fluidne inkluzije, skarnovsko ležište Rudnik

  • Integrative GHG Assessment in Oil and Gas Industry

    Aleksandar Mirković, Marija Živković, Stevan Đenadić, Darja Lubarda, Chinedu Anyanwa (2023)
    Reducing greenhouse gas emissions is one of the main targets of national strategies in European countries. As a main contributor to emissions, the energy sector is recognized as the most promising to apply measures and actions aimed to decrease GHG emissions. The Oil and Gas industry as a significant contributor to global greenhouse gas emissions is facing a growing need for estimating, mitigating, and reducing the impact of their operations on the atmosphere to stay competitive in a newly ...
    energetska tranzicija, gasovi staklene baste, industrija, nafta i gas
    ... methane. The quantity of methane emitted directly depends on methane sharc in the flared gas composition. In cases when flared gas composition is unknown API Compendium recommends default gas composition (CHa - 80 mole%, CxHs - 15 mole%, CsHs - 5 mole%). The CO emission factor for gas flaring ...
    ... usually expressed with respect to relative concentrations of CH+ and must be adequately scaled to Methanc content in the facility-associated gas composition before bcing applied. Additionally, CO>» can also be released from fugitive sources if CO, is present in the gas stream. In this case, the Methane ...
    ... Compendium recommended No combustion efficiency 98% for production Flare |« ——— & 99.5% for Refinery Flare Use API Compendium recommended gas composition. Stoichiometrically calculated No emission factor, adjusted for combustion efficiency to estimate CO> emissions. Estimate uncombusted CHu by ...

  • Environmental Energy Security Indicators as Tools for Environmental Protection

    Aleksandar Madžarević, Dejan Ivezić, Marija Živković , Miloš Tansijević (2019)
    Еколошка прихватљивост је постала незаменљив синтезни показатељ сваке валидне енергетске анализе у последње две-три деценије. Енергетска безбедност је у директној хармонији с еколошком прихватљивошћу кроз многе прописане политичке циљеве, економске користи, правне тековине итд. Индикатори еколошке сигурности представљају један од основних елемената за одређивање енергетске безбедности и снажне алате за усмеравање енергетског сектора ка одрживом развоју. У овом раду, анализа је била концентрисана на показатеље енергетске безбедности у области животне средине који се односе на сектор природног гаса у ...
    енергетска безбедност, еколошки енергетски индикатори, заштита животне средине, еколошка прихватљивост
    ... emission of sulfur oxide, because sulfur is not present, or only in the chemical composition of wood biomass. Natural gas is also characterized by no sulfur oxide emissions, unless the gas has hydrogen sulfide in its chemical composition. The easiest comparison of sulfur oxide emissions for different energy ...
    ... heat generated, ther is different amounts of emissions resulting from the combustion of fossil fuels. The reason for this is the different chemical composition of the energy that it burns. Their contribution to the emission of greenhouse gases, primarily carbon dioxide, is not the same, so a carbon ...
    ... Synthesis of this indicator is related to the composition of Emission of GHG (E1), Emissions of pollutants (E2) and Indirect environmental effects (E3) into ENVIRONMENTAL ACCEPTABILITY (E). A synthetic procedure is accomplished using the appropriate stage composition with a ranked outcome. The synthesis ...

  • The Fuzzy–AHP Synthesis Model for Energy Security Assessment of the Serbian Natural Gas Sector

    Aleksandar R. Madžarević, Dejan D. Ivezić, Miloš L. Tanasijević, Marija A. Živković (2020)
    Natural gas is used for the production of almost 20% of total energy today. The natural gas security of the Republic of Serbia is an urgent strategic, political and security issue. Serbia is one of the most vulnerable countries in Southeast Europe, because it only has one supply route. This study is a contribution to efforts to better understand the factors affecting energy security through the implementation of a new methodology based on the fuzzy–AHP synthesis model for measuring ...
    energetska bezbednost, prirodni gas, fazi AHP, AHP višekriterijumska analiza, fazi teorija
    ... appropriate fuzzy composition. Several models of composition were mentioned in the literature. For phenomena that carry potential negative connotations (risk, safety, etc.), the max–min composition was better considered [50]. According to [51], it has been proven that the max–min composition performs a more ...
    ... stage, the degree of agreement between the assumption and the rule is expressed [48]; • Max–min composition is one of the intensively used fuzzy composition models. It is also called a pessimistic composition due to the procedure by which it is performed—the presentation of a synthetic grade using a r ...
    ... grade, which is defined as the best possible among the worst expected individual grades [48,49]; • Min–max composition is a fuzzy composition model that is declared as an optimistic composition, because through it the synthetic grade is presented through a representative partial grade which is the worst ...

  • Palaeoflora of Kamenica (Pranjani Basin, western Serbia)

    Zorica Lazarević, Ljubica Milovanović, Jelena Milivojević, Ivana Vasiljević (2019)
    Palaeofloras of the Paleogene in Serbia are relatively rare, especially in comparison with floras from Neogene sediments. Most Paleogene phytoas sociations from the territory of Serbia existed in a dry and warm climate. The youngest Paleogene phytoassociation originates from the Pranjani Basin (Western Serbia), locality Kamenica. The age of this palaeoflora is determined as Late Oligocene. This fossil plant assemblage is different from other Paleo gene phytoassociations.The palaeoflora from Kamenica is characterized with leaf imprints larger than in other ...
    макрофлора, млађи олигоцен, Прањански басен, Каменица
    ... palaeoflora from Kamenica is characterized with leaf imprints larger than in other Paleogene fossil floras. Furthermore, it differs in taxonomical composition. The prevailing forms are conifers and represen- tatives of broad-leaved evergreen forests. In other Paleogene phytoassocia- tions, elements of ...
    ... ć, 2018; radOvIć, 2018; jOvaNOvIć et al., 2019a, b) and this paper is one more contri- bution to knowledge of these deposits. Palaeofloristic composition: The leaf imprints, presently being studied, orig- inate from dark-gray, very compact marls which lie across the serpentine. These sediments are ...
    ... vegetation elements of temperate climate are very rare, and represented only by a few imprints of Betulaceae and ulmaceae. Based on the taxonomical composition of palaeo- phytoassociation and leaf morphology, it has been inferred that the climate was subtropical and humid during the existence of this plant ...

  • ‘Blue-’ and ‘Brown-speckled’ pottery from Qalhât, the Sultanate of Oman (13–16th centuries): Comparison with traditional Omani 19–20 century productions

    Liliana Gianni, Hélène Renel, Aleksandar Kremenović, Philippe Colomban (2020)
    Representative ‘Blue speckled’ (13–16th centuries) and ‘Brown speckled’ (13–21st century) wares recovered from the excavations in Qalhât or collected around Bahlâ city (Sultanate of Oman) were characterized by XRPD, SEM-EDS, Raman/optical microspectroscopy, and thermal expansion. Minerals present in the body (quartz, augite and albite as major phases, calcite, dolomite, rutile, anatase, phosphate, hematite and magnetite as minor phases) were identified by XRPD and/or Raman spectroscopy. SEM-EDXS microanalysis was performed on the glazes in order to compare their composition, especially ...
    Firing, Glaze, Traditional ceramics, Provenance studies, Augite

  • Geotechnical zoning of the terrain along the first section of E-80 highway in Serbia – SEETO route 7

    Dragoslav Rakić, Zoran Berisavljević, Irena Basarić, Snežana Bogdanović, Jovana Janković (2019)
    Part of E-80 highway that passes through Serbia (from the city of Nis to the administrative border Merdare) is 77 km long. The highway is divided into two sections: the first from Nis to Plocnik (39.4 km long) and the second from Plocnik to the administrative border with Kosovo. The route is designed through a typical plain and hilly terrain in which different geological units are dominant: crystalline schists, neogene sediments of foothills and quaternary sediments in the valley ...
    ... wires. Amphibolites do not represent a permanent horizon, but appear in the form of lenses with max thickness of 10 m. Products of physical- chemical decomposition of this complex have different thicknesses, ranging from 0.5 m to over 5.0 m. More solid gneisses and amphibolite have thinner ...
    ... general strike direction SW-NE (Rakic et al., 2018). Figure 2. Regional rupture pattern - analysis of satellite images Geological composition of terrain is very heterogeneous in the wider zone of the highway route. It is built of crystalline schists (fine grained gneisses dominate ...
    ... stream and river valleys that have deposited proluvial sediments on both valley sides of the Toplica River. Based on age and lithological composition, terrain is divided in two parts: a younger Neogene complex downstream from the city of Prokuplje (km: 0-17.2) and an older Neogene complex ...

  • Understanding the effect of synthesis and sintering temperature on the functional properties of barium titanate/cobalt ferrite composites

    Marija Šuljagić, Aleksandar Kremenović, Ivan Petronijević, Adis Džunuzović, Miljana Mirković, Vladimir Pavlović, Ljubica Anđelković (2023)
    To investigate the effect of synthesis procedure and sintering temperature on the functional properties of perovskite/spinel ceramics, BaTiO3/CoFe2O4 composites were prepared by thermal decomposition, coprecipitation, and microemulsion method, and sintered at 1150°C and 1300°C. The phase composition and morphology of as-prepared powders as well as sintered ceramics were thoroughly examined by X-ray powder diffraction (XRPD) and scanning electron microscopy (SEM) coupled with electron dispersive spectroscopy (EDS). The dielectric and ferroelectric measurements were performed in detail. Generally, the ...
    Perovskite/spinel ceramics, Multiferroic, Sintering, Influence of synthesis method

  • 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

  • Towards Better Valorisation of Industrial Minerals andRocks in Serbia—Case Study of Industrial Clays

    Vladimir Simić, Dragana Životić, Zoran Miladinović (2021)
    Management, Monitoring, Policy and Law,Nature and Landscape Conservation
    ... or vein, with variable thickness and not uniform mineral composition, di- vided into smaller blocks by post- tec- tonic 25 50 100 Ceramic and refractory clays 1 Bedded and lenticular, with constant thickness and uniform composition, not divided into smaller blocks by post-tec- tonic and ...
    ... vari-able thickness and nonhomoge- neous composition, with reserves of 500,000 to 1,500,000 tonnes 25 50 100 Bedded and lenticular, with reserves less than 500,000 tonnes Common clays 1 Bedded and lenticular, of constant thick- ness and uniform composition, with re- serves greater than 5,000,000 ...
    ... reserves greater than 2,000,000 tons, composition and quality vary vertically and horizon- tally, with pronounced post-tectonic that significantly affects the operating condi- tions Bentonite 1 Bedded and lenticular, of constant thick- ness and uniform composition, which are not divided into smaller ...

  • Epidotizacija sanidina u kvarclatitima Grota

    Danica Srećković-Batoćanin, Suzana Erić, Nikola Novičić, Nikola Pašajlić, Natalija Batoćanin (2023)
    Propilitska alteracija je veoma česta u gornjokredno-tercijarnim vulkanitima Srbije. Kvarclatiti Grota, otkriveni na dubini od oko 550 m u jednoj od istražnih bušotina su holokristalaste porfirske strukture sa fenokristalima sanidina dimenzija i do 1,5 x 2 cm. Optičkim ispitivanjima su u kvarclatitu potvrdjeni i elementi sitaste, pojkilitske i glomeroporfirske strukture. Kao fenokristali prisutni su sanidin, plagioklas, kvarc, biotit i amfiboli. Sekundarni minerali su hlorit, epidot, coisit, Fe-hidroksidi, redak kalcit i ilit. U fenokristalima sanidina se zapažaju „lepeze“ izduženih kristala ...
    Grot, kvarclatiti, sanidin, epidot

  • Influence of mono- and two-component organic modifiers on determination of lipophilicity of tetradentate Schiff bases

    Nikola Stevanović, Aleksandar Mijatović, Aleksandar Lolić, Mario Zlatović, Rada Baošić (2021)
    The infuences of the application of mono- and two-component organic modifers on lipophilicity determination of 12 tetradentate Schif bases by reversed-phase thin layer chromatography were investigated. The main goal is to estimate types of interaction between observed compounds and components of the applied chromatographic systems and establish some behaviour pattern in order to easier choose a combination of organic modifers which will simulate interaction in biological systems based on the facts that the same basic intermolecular interactions are responsible ...
    Materials Chemistry, Industrial and Manufacturing Engineering, General Chemical Engineering, Biochemistry,General Chemistry

  • Influence of mono- and two-component organic modifiers on determination of lipophilicity of tetradentate Schiff bases

    Nikola Stevanović, Aleksandar Mijatović, Aleksandar Lolić, Mario Zlatović, Rada Baošić (2021)
    The infuences of the application of mono- and two-component organic modifers on lipophilicity determination of 12 tet radentate Schif bases by reversed-phase thin layer chromatography were investigated. The main goal is to estimate types of interaction between observed compounds and components of the applied chromatographic systems and establish some behaviour pattern in order to easier choose a combination of organic modifers which will simulate interaction in biological systems based on the facts that the same basic intermolecular interactions are ...
    Materials Chemistry, Industrial and Manufacturing Engineering, General Chemical Engineering, Biochemistry, General Chemistry

  • Sinteza i karakterizacija nanoprahova u CeO2-Bi2O3 sistemu

    Marija D. Prekajski (2014-04-04)
    Nanoprahovi kristalnih faza iz serije čvrstih rastvora u pseudo-binarnom sistemuCeO2-Bi2O3 sintetisani su primenom jednostavne i ekonomične samopropagirajućemetode na sobnoj temperaturi korišćenjem nitrata metala i natrijum-hidroksida kaopolaznih supstanci. Osim krajnjih članova niza, CeO2 i niskotemperaturne polimorfnemodifikacije α-Bi2O3, sintetisani su i čvrsti rastvori nominalnog sastava Ce1-xBixO2-δ,gde je x = 0,1; 0,2; 0,3; 0,4; 0,5; 0,6; 0,7; 0,8; 0,9. Rezultati proučavanja metodomrendgenske difraktometrije na polikristalnom materijalu i ramanske spektroskopskeanalize pokazali su da su sintetisani prahovi sa nižim sadržajem bizmuta (x = 0,1 ...
    nanostrukturni materijali, čvrsti rastvori, CeO2, Bi2O3, rendgenskadifraktometrija praha, Ritveldova metoda, mikrostrukrurna analiza