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Упит dcterms_subject_txt:grain size distribution

508 items

  • Selection of Artificial Lift Methods: A Brief Review and New Model Based on Fuzzy Logic

    Miroslav Crnogorac, Miloš Tanasijević, Dušan Danilović, Vesna Karović Maričić, Branko Leković (2020)
    Artificial lift methods have applications in oil wells where oil production is no longer possible due to natural reservoir energy, so this necessary energy is added by introducing lift methods. In order to achieve optimum production, the selection of an artificial lift method is very important. This paper uses fuzzy logic as a mathematical and conceptual model for selection of the optimal artificial lift method. The outcome or IF-THEN rules, as the central part of the model, is based ...
    mehaničke metode, proizvodnja nafte, fazi logika, donošenje odluka, optimizacija
    ... translated into grades based on the distribution of oil by density [19]: light—0.85; medium heavy 0.85–0.93; heavy 0.93–1.00; very heavy 1.00– The B5 parameter is viscosity. The viscosity values of the fluid are translated into grades based on the distribution of hydrocarbons viscosity (relative) ...
    ... = (μM1, …, μM10) Where: MAXj = max{MINo}, for every j and MINo = min{μAj = 1, …, 10, μBj = 1, …, 10, μCj = 1, …, 10}, for all o = 1 to O. The size O represents the outcome, which is defined for each possible combination of input parameters. The outcome is defined on the basis of empirically defined ...
    ... where: MAXj = max{MINo}, for every j and MINo = min{µA j = 1, . . . , 10, µB j = 1, . . . , 10, µC j = 1, . . . , 10}, for all o = 1 to O. The size O represents the outcome, which is defined for each possible combination of input parameters. The outcome is defined on the basis of empirically defined ...

  • Temperature induced evolution of nanostructured Ni0.9Zn0.1O

    Kremenović Aleksandar, Antić Bratislav, Vučinić-Vasić Milica, Colomban Philippe, Jovalekić Čedomir, Bibić Nataša, Kahlenberg Volker, Leoni Matteo (2010)
    The crystal structure and microstructure of as-prepared and annealed Ni0.9Zn0.1O were refined at room temperature in both the Fm (3) over barm and R (3) over barm space groups. It is shown that below the Neel point (458 K), where magnetic ordering triggers the presence of a trigonal strain, the common usage of a higher-symmetry non-admissible space group for crystal structure and microstructure analysis via the Rietveld method may result in both an incorrect structure description and incorrect microstructure ...

  • 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

  • Hypogene speleogenesis related to porphyry magmatic intrusions and its influence on subsequent karst evolution in the Peruvian high Andes

    Alexander Klimchouk, David Evans, Sasa Milanovic, Cristian Bittencourt, Mauro Sanchez, F. Carlos Aguirre (2022)
    Earth-Surface Processes

  • Heavy metals in lignite and soil of Kostolac-Kovin coal basin, eastern Serbia - comparative analysis with selected cities in Serbia, region, Europe and world

    Bogoljub Vučković, Bojan Dimitrijević (2023)
    The Kostolac-Kovin coal basin with an area of 320 km2, with 5 separate layers of coal and with a total of about 5.7 Bt of geological resources and reserves represents an exceptional potential for coal production in Serbia. The coal resources listed in this way are not fully exploitable, but they represent potential for consideration. In this paper, we deal with the geochemical characteristics of coal seams and perform a comparative analysis of coal affectation on the environment. With ...
    lignite, heavy metals, concentrations
    ... ıdcocrsayoocrszloop?aziO Figure 4. General view of the horizontal distribution of Zn, Cu and Pb in the I, I and II coal seams of the Kostolac- Kovin coal-bearing basin; blue — increased values, yellow — decreased values VERTICAL DISTRIBUTION A large number of individual samples were taken in the vertical ...
    ... including the surface humus layer, gravel, coal layers and all types of clay and sand. A presentation of the vertical distribution of Zn, Pb, Cu is given (Figure 5). 180 Vertical distribution Zn (ppm) Surface soil, humus BHWIIAGIGII II Q3 Quaternarygravel E 47 Quaternaryclays 00008 322 Quaternarysands ...
    ... environment. P/ith 155 analyzes of HM from coal, 45 from ash, 165 from gravel and 30 from soil, we perform analysis of horizontal and vertical distribution of HM and comparative analysis. B/hat interests us as authors and you as readers the most is - whether heavy metals from coal contaminate the ...

  • The use of biological markers in determination of origin and type of organic matter in the Tisza river sediments

    Snežana Štrbac, Gordana Gajica, Aleksandra Šajnović, Nebojša Vasić, Ksenija Stojanović, Branimir Jovančićević (2013)
    The objective of the study was to determine the origin and type of organic matter (OM) of the Tisza recent sediments along the distance of 153 km through the territory of Serbia. For this purpose group organic-geochemical parameters and biomarker compositions were used. All samples contain approximately same amount of OM, which was deposited under uniform, slightly reducing conditions. Based on the distribution of n-alkanes, the origin and type of OM could not be precisely estimated. However, n-alkane patterns ...
    sediments, Tisza River, organic matter, biomarkers, oil pollutants
    ... origin. This primarily refers to n-alkanes. In crude oils, n-alkanes have uniform distribution of odd and even homologues (the Carbon Preference Index, CPI, is about 1), usually in the range of C10–C35. An n-alkane distribution with a strong predominance of lower homologues C12–C22 indicates algal organic ...
    ... Preference Index (CPI) determined for the full distribution of n-alkanes C16–C35 (mass chromatogram m/z 71), CPI (C16–C35) = 1/2 [Σodd(n-C17–n-C35) / Σeven(n-C16–n-C34) + Σodd(n-C17–n-C35) / Σeven(n-C18–n- –C36)]; bCPI determined for the distribution of n-alkanes C16–C22 (mass chromatogram m/z 71) ...
    ... 2)]; cCPI deter- mined for distribution of n-alkanes C23–C35 (mass chromatogram m/z 71), CPI (C23–C35) = 1/2 [Σodd(n-C23– –n-C35) / Σeven(n-C22–n-C34)+Σodd(n-C23–n-C35) / Σeven(n-C24–n-C36)]; dPr/Ph = pristane/phytane Tricyclic and pentacyclic terpanes. The distribution of tricyclic diterpanes and ...

  • Density maps from gravity inversion as a tool for the basin basement analysis and imaging

    Ivana Vasiljević (2023)
    Previously devised method for density mapping of the Cenozoic basin’s basement is further developed in order to improve the visualization and geological interpretation of the results. The method combines gravity-density inversion with forward modeling and requires gravity anomaly and depth-to-basement data. Although it was primarily designed for application in well-researched basins, such as Pannonian basin, method does not require further constrains. An information on density distribution in the Cenozoic sediments (from density logging or core density measurements) is important ...

  • Model of the Geomagnetic reference field of the Republic of Serbia

    Spomenko J. Mihajlović, Vesna Cvetkov (2024)

  • Spatial distribution of major and trace elements in artificial lakes in Serbia: health risk indices and suitability of water for drinking and irrigation purposes

    Goran Marković, Aleksandar Ž. Kostić, Nebojša Đ. Pantelić, Radojka Maletić, Jana Štrbački, Jovan Cakić, Lazar Kaluđerović, Biljana P. Dojčinović, Angelo Maria Giuffrè, Jelena B. Popović-Djordjević (2023)
    Lakes and reservoirs are the main water resources for household, irrigation, and industrial use. Hence, it is necessary to control water pollution and have reliable information on water quality, which refers to its suitability for a particular purpose. The main objective of this study was to evaluate the suitability of water for drinking and irrigation purposes from ten artificial lakes on the territory of the Republic of Serbia. The physicochemical parameters were determined using standard analytical methods, whereas the ...
    Management, Monitoring, Policy and Law, Pollution, General Environmental Science, General Medicine

  • Distribution of Uranium and Rare Elements in Radioactive Phosphate-Bearing Anomalies in Southeast Mongolia

    Boris Vakanjac, Neil Rutherford, Vesna Ristić Vakanjac, Tanita Đumić, Suzana Đorđević Milošević (2020)
    Soviet and Mongolian geologists initiated geological exploration of Mongolia for minerals after World War II (1945). These activities lasted until the breakup of the USSR in 1991. As part of this exploration systematic uranium and rare element exploration was undertaken across Mongolia. New exploration resumed in Mongolia at the beginning of the 21st century for a range of ore and mineral deposit styles including uranium, coal, base and precious metals and Fe-ore. This was generally undertaken by Western-based companies. This ...
    uran, radioaktivnost, kreda, retki elementi, fosfati, anomalije, Dornogobi

  • Influence of DEM resolution on numerical modelling of debris flows in RAMMS - Selanac case study

    Jelka Krušić, Biljana Abolmasov, Mileva Samardžić Petrović (2019)
    Debris flows induced by intensive rainfall represent very hazardous phenomena in many parts of the World. Methods for prediction of runout distance of flow like mass movements are different and depending on the input data, rheology, and available or appropriate numerical solution. However, sometimes it is not easy to obtain pre event and post event high-resolution data in the rural or mountainous area. Thus, the topology of terrain is the most important input parameter for the every real case ...
    tecišta, modeliranje, RAMMS, DEM
    ... magmatic rocks with Palaeozoic metamorphic rocks. Debris flow material is highly heterogeneous in lithological composition, as well as grain size distribution (up to m 3 boulders) (Fig. 3). Figure 3 UAV images of a) soure area b) transportation zone (April 2017) Proceedings of the 4thSymposium ...

  • Distribution of Potentially Toxic Elements in the City of Zintan and Its Surroundings (Northwestern Libya) by Surface Soil Sampling

    Boris Vakanjac, Zorana Naunović, Vesna Ristić Vakanjac, Tanita Đumić, Saša Bakrač, Jana Štrbački, Vuk Gajić, Taher Mohamed Alzarog (2023)
    The study area is the city of Zintan, in northwestern Libya, which has grown over the past 30 years. Its current population is roughly 30,000. Although the city is in part commercial, most of the population engages in agriculture and primarily grows cereal crops (wheat and barley). The demand of the growing city for agricultural products has increased, intensifying the use of fertilizers, pesticides, and insecticides. Consequently, concentrations of potentially toxic elements (PTE) in the soil have increased. To ...
    Geologija, Geotehničko inženjerstvo, Inženjerska geologija

  • 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

  • Uniaxial compressive strength test before and after standard fire test on rock mass

    Stefan Mitrović, Goran Todorović, Bojan Kostić, Milica Mirković-Marjanović, Nikola Božović, Marija Krstić, Aleksandar Erić, Radovan Gospavić, Snežana Ilić, Aleksandar Kijanović (2022)
    ... INTRODUCTION Uniaxial compressive strength testing is a parameter that is determined experimentally. It depends on the structure of the rock mass, grain size and orientation, number and arrangement of cracks and fissures. For the same rock, strength may be different, depending on physical characteristics ...
    ... of this mineral during transport. The rock fragments are rounded, sometimes jagged, up to 0.1 mm in size. There are also fragments of carbonate rocks, which do not differ from other grains in size and shape. The mentioned diversity indicates a wider area of erosion from different types of rocks ...
    ... . Some have undulatory extincion due to the effect of pressure, which tells us that they are at least partly of metamorphic origin. The different size of this mineral, poorly sorted indicates a relatively short transport of the material. Crystal fragments are less presented, mostly small and ...

  • Arsenic in Tap Water of Serbia´s South Pannonian Basin and Arsenic Risk Assessment

    Petar Papić, Marina Ćuk, Maja Todorović, Jana Stojković, Bojan Hajdin, Nebojša Atanacković, Dušan Polomčić (2012)
    kvalitet podzemnih voda, arsen, analiza rizika, Panonski Basen
    ... Pannonian Basin exhibited an unsatisfac- tory water quality, which is a result of complex geological and hydrogeochemical characteristics. In view of the size of the test area, it was divided into three districts: Banat, Bačka, and Srem. Based on the examples presented, the variation in arsenic concentrations ...
    ... Arsenic concentra- tions vary from 50 to 100 µg/L, with some municipalities recording up to 250 µg/L [19]. The aim of our study was to report current distribution of arsenic in drinking water from the public water supply system in the South Pannonian Basin and to show the effects of drinking arsenic-rich water ...
    ... with the highest arsenic concentration being 234 µg/L, while in Srem 77% of the samples were compliant. The importance of this research of the distribution of arsenic in groundwa- ters used for drinking water supply, in addition to its scien- tific contribution, is primarily related to the impact of ...

  • Photocatalytic Activity of the V2O5 Catalyst toward Selected Pharmaceuticals and Their Mixture: Influence of the Molecular Structure on the Efficiency of the Process

    Sanja J. Armaković, Aleksandra Jovanoski Kostić, Andrijana Bilić, Maria M. Savanović, Nataša Tomić, Aleksandar Kremenović, Maja Šćepanović, Mirjana Grujić-Brojčin, Jovana Ćirković, Stevan Armaković (2023)
    Due to the inability of conventional wastewater treatment procedures to remove organic pharmaceutical pollutants, active pharmaceutical components remain in wastewater and even reach tap water. In terms of pharmaceutical pollutants, the scientific community focuses on -blockers due to their extensive (over)usage and moderately high solubility. In this study, the photocatalytic activity of V2O5 was investigated through the degradation of nadolol (NAD), pindolol (PIN), metoprolol (MET), and their mixture under ultraviolet (UV) irradiation in water. For the preparation of V2O5, facile ...
    DFT analysis, metoprolol, nadolol, nanomaterial characterization, photocatalysis, pindolol, β-blocker
    ... speed of 5.1 ?/min. The low background sing}|e crystal silicon sample holder minimizes the background. Unit cell parameters and average crystallite size and lattice strain values were obtained by PDXL2 integrated X-ray powder diffraction software (Version 2.8.30; Rigaku Corporation, Tokyo, Japan) ...
    ... analyzed by Shi- madzu UFLC-PDA (Shimadzu Scientific Instruments, Columbia, Maryland, USA) Eclipse XDB-C18 column, 1550 mm x 4.6 mm i.d., particle size 5 um, 30 *C). The UV/Vis PDA detector was set at wavelengths of maximum absorption of each B-blocker: 210 nm (for NAD), 217 nm (for PIN), and 223 ...
    ... hydrothermal synthesis was used. X-ray diffraction identifies only one crystalline phase in the sample, which is proven by the fact that the crystallite size (1251(35) A) and lattice strain (0.16(2)%) values point to well-crystallized material with a significant lattice strain. SEM micrographs show that ...

  • 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
    ... A MMain Contactor Size: 38 A Delta Contactor Size: 38 A Star Contactor Size: 25 A Overioad Relay Size: 18 to25 Amps Required Cable Size: 3CxCopper 25 Samm Recommended Cable Size' 3CxCopper 25 Samm cCable Gland Size 25 MM Terminal Block Size: 63 A Cable Lug Size 25 samm Recommended ...
    ... d Crimping Tool: 16X25 MM Control Wiring Cable Size: 1.5 sSamm Power Wiring Cable Size' Copper 25 Samm 23 7. SAKUbYUAK V OBOM Ppajiy JeTaJbHO je aHajmnHpaH Hpomnec JHMcCH3HOHHCaHba CHcTeMa 3aBOJHHX HyMmu (Progressive Cavity Pumps - PCP) y Korrekcry Ha(THe H racHc HHJIyCTpHJe, Ca IIOCeCOHHM ...

  • Gas-lift wells optimization at the oil field "K"

    Dušan Danilović, Marija Ilić, Miroslav Crnogorac, Lola Tomić (2022)
    naftna bušotina, raspodela gasa, gas-lift, optimizacija

  • E-Connecting Balkan Languages

    Cvetana Krstev, Ranka Stanković, Duško Vitas, Svetla Koeva (2009)
    In this paper we present a versatile language processing tool that can be successfully used for many Balkan languages. This tool relies for its work on several sophisticated textual and lexical resources that were developed for most of Balkan languages. These resources are based on several de facto standards in natural language processing.
    Query expansion, e-dictionary, wordnet, proper name, aligned text
    ... automatically prepared comprising from texts in some limited technical domain [18], to more versatile literary corpora [5] that are often more modest in size but minutely prepared. The main textual resource used to explore WS4LR is Jules Verne’s novel Around the world in eighty days. This text was ...
    ... first built wordnet was English wordnet, so-called Princeton Wordnet (PWN), having today approximately 140,000 synsets. Due to its remarkable size and successful inclusion in various computer-based applications it is considered as a de facto standard upon which wordnets for many other languages ...
    ... translation [21]. Finally, from the practical point of view its suitability stems from the fact that it presents the sample text for the French distribution of the Unitex system [15]. Versions of the novel in fifteen languages have been acquired, but not all of these texts have yet been aligned; ...

  • Overwiew of In-Pit Crushing & Conveying Technology in Open Pit Mines

    Ali Nasirinezhad, Dejan Stevanović, Dragan Ignjatović, Petar Marković (2021)
    The conditions under which contemporary surface mining operations is carried out obviously becoming increasingly complex. In such complex conditions, the optimization of haulage systems as the technological phase with the largest share in the total operating costs, is very important from the aspect of achieving profitability of the mining project. In a large number of cases, the application of traditional haulage systems with trucks (as the most dominant type of haulage in open pit mines) does not lead to ...
    In Pit Crushing and Conveying, IPCC, open pit mining, haulage, optimization, costs saving