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Упит dcterms_subject_txt:fluid loss control

351 items

  • 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

  • Gate Road Support Deformation Forecasting Based on Multivariate Singular Spectrum Analysis and Fuzzy Time Series

    Luka Crnogorac, Rade Tokalić, Zoran Gligorić, Aleksandar Milutinović, Suzana Lutovac, Aleksandar Ganić (2021)
    Underground mining engineers and planners in our country are faced with extremely difficult working conditions and a continuous shortage of money. Production disruptions are frequent and can sometimes last more than a week. During this time, gate road support is additionally exposed to rock stress and the result is its progressive deformation and the loss of functionality of gate roads. In such an environment, it is necessary to develop a low-cost methodology to maintain a gate road support system. ...
    deformacije podgrade, lasersko skeniranje, višekanalna singularna spektralna analiza, prognoza, klasterisanje fuzzy vremenskih serija
    ... last more than a week. During this time, gate road support is additionally exposed to rock stress and the result is its progressive deformation and the loss of functionality of gate roads. In such an environment, it is necessary to develop a low-cost methodology to maintain a gate road support system. For ...
    ... last more than a week. During this time, gate road support is additionally exposed to rock stress and the result is its progressive deformation and the loss of functionality of gate roads. In such an environment, it is necessary to develop a low-cost methodology to maintain a gate road support system. For ...
    ... bounded by B(t) =[Bl(t),Bu(t)] at the current time t, where Bl(t) represents the lower edge and Bu(t) represents the upper edge of the support. Without loss of generality, we equal the upper edge with the lower and transform the surface of the support into one line, i.e., we reduce a real two-dimensional ...

  • Review: Methodological approaches and research techniques for addressing construction and remediation problems in karst reservoirs

    Saša Milanović, Ljiljana Vasić (2021)
    Earth and Planetary Sciences (miscellaneous), Water Science and Technology

  • Optimizacija ispirnih fluida za bušenje dirigovanih bušotina

    Vukoman Krgović (1994)
    Ispirni fluidi, dirigovano bušenje

  • Језички модели, шта је то?

    Ми­ха­и­ло Шко­рић (2023)
    Језички модели

  • 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
    ... – rpaBHranmuoHa KoHcTaHra (9.81 m/s?), 1) — e(-)HKaCHOCT CHCTEMAa. CodQrBepcku anmara 31 mnpopauyH: PumpSizer, CFD camyanuje (Computational Fluid Dynamics) H cnemMjaHMM3OBaHH NIporpaMM 3a HaQTHy HHJIycTpHJy OMoOryhaBajy IIpeH3HO MOJIeJIHpabbe pajia 3aBOJHHX IIyMIIH. OnBH aJlarH KOpHcTe yJHa3He ...
    ... ToMD ID Wall thickness: Roughness " 4 m Y|m Y |mm Y|mm 7 |mm ii 1 |Casing Y Casing 0 809.878 121.3612 9.1694 0.0254 & tEdit'Black Oil' B x FLUID Name: Black Oil Save as template Description: Properties | Viscosity | Calibration | Thermal STOCK TANK PROPERTIES CONTAMINANT MOLE FRACTIONS ...
    ... H raca Kpo3 IeB KaJa Je npucyTHa BoJla. OBa Kopenarnuja y3HMa y 003Hp rycCTHHy, BHCKO3HTCT, IIpHTHCaK H TeMIIepaTyPpy. & Edit Black Oil' B x FLUID Name: - |BlackOil Save as template Description: Properties Viscosity | Calibration | Thermal UNDERSATURATED OIL MIXTURE Correlation: Vasquez ...

  • BaTiO3/NixZn1−xFe2O4 (x = 0, 0.5, 1) Composites Synthesized by Thermal Decomposition: Magnetic, Dielectric and Ferroelectric Properties

    Marija Šuljagić, Ivan Petronijević, Miljana M. Mirković, Aleksandar Kremenović, Adis Džunuzović, Vladimir B. Pavlović, Aleksandra Kalezić-Glišović, Ljubica Andjelković (2023)
    To investigate the influence of spinel structure and sintering temperature on the functional properties of BaTiO3/NixZn1−xFe2O4 (x = 0, 0.5, 1), NiFe2O4, ZnFe2O4, and Ni0.5Zn0.5Fe2O4 were in situ prepared by thermal decomposition onto BaTiO3 surface from acetylacetonate precursors. As-prepared powders were additionally sintered at 1150 °C and 1300 °C. X-ray powder diffraction (XRPD) and scanning electron microscopy (SEM) coupled with electron dispersive spectroscopy (EDS) were used for the detailed examination of phase composition and morphology. The magnetic, dielectric, and ...
    ferroelectric, dielectric properties, magnetic properties, titanate/ferrite composites, phase composition
    ... dielectric properties of such composites are mainly determined by the amount of con- ductive oxide phases. The loss tangents for the samples sintered at 1300 ?"C are lower in comparison to the loss tangents values of samples sintered at 1150 "C in the low and mid requency range, Figure 6b. This clearly ...
    ... frequency-dependent tangent loss values for the samples sintered at 1150 "C show a typical behavior of composites with inhomogeneous conductivity. Interestingly, in the case of samples sintered at 1300 "C, in the high-temperature range, the values of high-frequency tangent loss increased due to the defects ...
    ... Temperature dependence of mass magnetization in the applied magnetic field of 50 ka/m for all sintered samples. The relative dielectric constant and the loss tangent as a function of frequency along; with corresponding, AC conductivity are shown in Figure 6. In the low and mid frequency range, the dielectric ...

  • Comprehensive Profiling of Microbiologically Induced CaCO3 Precipitation by Ureolytic Bacillus Isolates from Alkaline Soils

    Olja Šovljanski, Lato Pezo, Jovana Stanojev, Branimir Bajac, Sabina Kovač, Elvira Tóth, Ivan Ristić, Ana Tomić, Aleksandra Ranitović, Dragoljub Cvetković, Siniša Markov (2021)
    MICP process, kinetic study, calcite, vaterite, MALDI-TOF identification, Bacillus licheniformis, Sporosarcina pasteurii
    ... all samples with FTIR analysis. Weight loss dynamics below 400 ◦C vary to a certain extent probably due to a difference in precipitate microstructure (density and particle size), as well as absorbent water. The second part of the DTA diagram shows rapid weight loss above 600 ◦C, followed by a strong peak ...
    ... temperatures and pH values [18]. Sporosarcina pasteurii DSM 33 was used as a positive control for the MICP through ureolysis, while carbonate-induced bacterium Bacillus pseudofirmus DSM 8715 was a negative control for ureolytic activity. The mentioned groups of bacterial isolates were well as referent ...
    ... ◦C/min. Two stages in the thermal analysis may be noticed, below and above 400 ◦C. Below 400 ◦C three peaks are noticeable followed by a minor weight loss. The first one occurring around 115 ◦C is assigned to evaporation of humidity. The other two peaks around 220 and 290 ◦C probably represent the dec ...

  • Atmospheric exposure vs burying: influences on damage intensity of built-in kersantite in the monument of the Small Staircase (Belgrade, Serbia)

    Nevenka Novaković, Predrag Dabić, Vesna Matović (2023)
    Proučavan je efekat „zatrpanog kamena“ na intenzitet procesa degradacije prisutnih na kersantitu koji je ugrađen u spomenik Malo stepenište. Istraživanja su vršena na uzorcima stene iz kamenoloma i na oštećenim kamenim blokovima ugrađenim u spomenik. Dok su neki delovi stepeništa bili pod zemljom 90 godina, većina kamenih elemenata je bila izložena različitim uslovima sredine i antropogenim uticajima. Urađeno je detaljno mapiranje trenutnog stanja spomenika kako bi se istražio uticaj “zatrpavanja” i kompleksne geometrije spomenika na tip propadanja i variranje ...
    Raspadanje, Indeks oštećenja, Zatrpavanje, Fizička svojstva, Kersantit

  • Multi-Criteria Fuzzy-Stochastic Diffusion Model of Groundwater Control System Selection

    Dušan Polomčić, Zoran Gligorić, Dragoljub Bajić, Miloš Gligorić, Milanka Negovanović (2019)
    When considering data and parameters in hydrogeology, there are often questions of uncertainty, vagueness, and imprecision in terms of the quantity of spatial distribution. To overcome such problems, certain data may be subjectively expressed in the form of expert judgment, whereby a heuristic approach and the use of fuzzy logic are required. In this way, decision-making criteria relating to an optimal groundwater control system do not always have a numerical value. Groundwater control scenarios (alternatives) are identified through hydrodynamic ...
    expert judgment, linguistic variables, fuzzy dynamic TOPSIS, hydrogeology, groundwater control system, open-cast mine, geometric Brownian motion

  • DFT study of free radical scavenging activity of erodiol

    Zoran Marković, Jelena Đorović, Milan Dekić, Milanka Radulović, Svetlana Marković, Marija Ilić (2013)
    Antioxidant activity of erodiol was examined at the M05-2X/6-311+G(d,p) level of theory in the gas and aqueous phases. The structure and energy of radicals and anions of the most stable erodiol rotamer were analyzed. To estimate antioxidant potential of erodiol, different molecular properties were examined: bond dissociation enthalpy, proton affinity together with electron transfer energy, and ionization potential followed by proton dissociation enthalpy. It was found that hydrogen atom transfer is the prevailing mechanism of erodiol behavior in gas; ...
    депсиде, еродиол, механизми за уклањање слободних радикала, БДЕ, ИП, ПА

  • Fuzzy optimization in hydrodynamic analysis of groundwater control systems: Case study of the pumping station “Bezdan 1”, Serbia

    Dragoljub Bajić, Dušan Polomčić (2014)
    A groundwater control system was designed to lower the water table and allow the pumping sta-tion “Bezdan 1” to be built. Based on a hydrodynamic analysis that suggested three alternative solutions, mul-ticriteria optimization was applied to select the best alternative. The fuzzy analytic hierarchy process methodwas used, based on triangular fuzzy numbers. An assessment of the various factors that influenced the selec-tion of the best alternative, as well as fuzzy optimization calculations, yielded the “weights” of the alternativesand the ...
    groundwater lowering, groundwater management scenario, fuzzy analytic hierarchy process,expert knowledge, triangular fuzzy numbers, linguistic variables
    ... analysis of groundwater control systems: Case study of the pumping station “Bezdan 1”, Serbia Dragoljub Bajić, Dušan Polomčić Дигитални репозиторијум Рударско-геолошког факултета Универзитета у Београду [ДР РГФ] Fuzzy optimization in hydrodynamic analysis of groundwater control systems: Case study ...
    ... or fuzzy variable is Fuzzy optimization in hydrodynamic analysis of groundwater control systems: Case study of the pumping station “Bezdan 1”, Serbia DRAGOLJUB BAJIĆ1 & DUŠAN POLOMČIĆ2 Abstract. A groundwater control system was designed to lower the water table and allow the pumping sta- tion “Bezdan ...
    ... s.l. The groundwater control system is comprised of 17 wells, whose capacity is 40 l/s each. The time needed to lower the water table to below the design elevation is 8.5 days. Based on the predictive analysis and the three iden- tified alternatives for the groundwater control system, as described in ...

  • Application of Project Management Process on Environmental Management System Improvement in Mining-Energy Complexes

    Jelena Malenović Nikolić, Dejan Vasović , Ivana Filipović , Stevan Mušicki, Ivica Ristović (2016)
    menadžment, rudrastvo i energetski kompleksi, okruženje, održivi razvoj, mrežno planiranje
    ... probability (P) and the measure of loss (L) it inflicts: R = f(P, L) (1) Energies 2016, 9, 1071 6 of 20 Actualization of a risk event in a mining and energy complex leads to heavier or smaller economic loss, but also to serious consequences for the environment or loss as non-economic measure [22]. ...
    ... mining and energy complexes are the prerequisite for quality organization of preventive measures of environmental protection, for reduction of financial loss due to amelioration of the effects, and for minimization of the time to complete the tasks of the environmental management system. The problem with ...
    ... was implemented through the network of automatic stations for monitoring air quality, in accordance with the Decree on establishing the Air Quality Control Program in the state network and in local networks of area monitoring. Automatic monitoring was conducted for measuring the concentration of sulfur ...

  • 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
    ... TGA Analysis Figure 1a shows the TGA curve and derivative weight loss (DTG) curve of pre- extracted lignite. The first peak at 90.8 ◦C corresponds to loss of moisture. Degradation of OM starts at about 300 ◦C and the greatest weight loss is observed in the temperature interval between 400 and 500 ◦C, ...
    ... Faculty of Chemistry. Polymers 2021, 13, 759 5 of 25 Figure 1. The characteristic weight loss (thermogravimetric analysis, TGA), differential scanning calorimetry (DSC), and derivative weight loss (DTG) curve of lignite (a), HDPE (b), and the lig- nite/HDPE mixture (c). 2.5. Analysis of Lignite ...
    ... with the maximum at 471.2 ◦C. With further heating from 500 to 800 ◦C, the weight loss is less intense (<5% with temperature rise of 100 ◦C). The peak recorded at a temperature of 693 ◦C represents mostly mass loss caused by thermal alteration of minerals (clay and carbonate) [50]. The TGA curve shows ...

  • 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
    ... irena.basaric@rgf.bg.ac.rs CONTROL OF SUBSTRUCTURE CONSTRUCTION OF RAILWAYS IN THE REPUBLIC OF SERBIA Abstract Control of compaction of natural soil (in excavation) or compacted in the embankment during the construction of roads is one of the basic forms of quality control of the substructure. When ...
    ... Измењено: 2023-11-27 11:17:47 Control of substructure construction of railways in the Republic of Serbia Dragan Lukić, Dragoslav Rakić, Irena Basarić Ikodinović Дигитални репозиторијум Рударско-геолошког факултета Универзитета у Београду [ДР РГФ] Control of substructure construction of railways ...
    ... Within this paper, the technical regulations governing the control of compaction in the construction of railway infrastructure in the Republic of Serbia are presented. Keywords: substructure, technical regulations, embankment, compaction, control : 601 STEPGRAD2022 PROCEEDINGS OF INTERNATIONAL ...

  • 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
    ... confirms the presence of quartz (river sand) and or silicate fume (SiO2) [35]. In this temperature interval (200–600 ◦C) determined mass loss by TG analysis was 3.11%. Weight loss in the third temperature interval (600–800 ◦C) of 2.35% and the endothermic peak at 727 ◦C, is caused by the decomposition of the ...
    ... replacement for cement. Namely, the results showed that the lack of slag in terms of the content of SiO2, Al2O3, Fe2O3, and unburned carbon, and the loss of ignition, may be overcome by the thermal treatment of the slag prior to use, up to 650 ◦C. Results also showed that other physical– chemical cha ...
    ... dehydration and decomposition of the hydrates of the silicate-oxides, as well as calcium silicate-oxides [34]. This process has been followed with a weight loss of around 2.60% on the TGA curve. In the second temperature interval (200–600 ◦C) endothermic peaks are observed at 373, 460, and 573 ◦C. The peaks ...

  • Development Of The Serbian Geological Resources Portal

    Ranka Stanković, Jelena Prodanović, Olivera Kitanović, Velizar Nikolić (2011)
    ... at http://geoliss.rgf.rs/index.php?page=atlas, was created with the use of Adobe flash plug-in Zoomify, which enables zooming in real-time, without loss of image quality. Multimedia part of the web portal The part of the web portal pertaining to geoheritage and geodiversity of North-Western Serbia ...
    ... pages for database search. Web GIS For several projects online GIS maps were created with the ArcGIS extension: HTML ImageMapper NG2, allowing full control over cartographic quality and functionality. This approach was implemented for small to medium sized GIS Projects, whose geo data have little need ...

  • Self-Engineering: Possibilities for Maintenance Operations in the Mining Machines Industry

    Steven Manders, Milorad Pantelić, Vladimir Milisavljević, Alberto Martinetti (2021)
    Self-engineering is a relatively new branch of knowledge that aims to understand how systems could “autonomously” re-configure or repair themselves without the intervention of the operators. A direct field of application is within the maintenance spectrum. Having systems or machines capable of self-detecting or even self-repairing could represent a game-changer, in capital asset fields such as the mining industry in particular. This paper aims to investigate the possible benefits and challenges of self-engineering / self-maintenance concerning mining machines, specifically bucket-wheel ...
    self-engineering, self-maintenance, maintenance operations, mining industry, bucket-wheel excavator, gearbox revitalization

  • 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
    ... _ Paragonite 4 – - (Baccour et al., 2008) as a *dark-firing' ceramic body (Dondi et al., 2001; Milošević & Logar, 2017). The relatively large loss on ignition (LOI; 15.86%) may be related to dehydroxylation of hydrated minerals or hydroxides, oxidation of organic materials and decomposition ...
    ... investigated samples show a couple of endothermic peaks (Fig. 5). The first significant endothermic peak at between 120% and 220%C is associated with the loss of adsorbed and interlayer water and indicates the presence of layered silicates such as illite, kaolinite, halloysite and/or mont- morillonite ...
    ... C. Mackenzie, editor). London, UK. Mineralogical Society. Grim R.E. & Rowland R.A. (1944) Differential thermal analysis of clays and shales, control and prospecting method. Journal of the American Ceramic Society, 27, 65–76. Joussein E., Petit S., Churchman J., Theng B., Righi D. & Delvaux B ...

  • Application of machine learning for diagnosing the operation of a deep well pump in oil production

    Maja Trikić (2024)
    This paper will thoroughly examine how machine learning can improve the diagnosis of deep well pumps by analyzing the role and function of the pumps, dynamograms, sensor technologies, and diagnostic methods.Our analysis will provide insights into modern techniques and approaches for enhancing the performance and reliability of oil production systems, targeting cost reduction and increased operational efficiency.
    deep well pump, dynamograms, machine learning, diagnostics of operating coditions,Random Forest, XGBoost
    ... in submersible pumps, as well as in many industrial, commercial, and scientific applications. These sensors enable precise measurement and control of fluid and gas pressures, which is crucial for identifying and addressing problems in submersible pump systems. Proper operation of submersible pumps ...
    ... weight of the sucker rods immersed in the fluid, the weight of the fluid column in the tubing above the downhole pump, pressure load on the tubing and annular space, the weight of the fluid column in the annulus, and frictional forces arising: from fluid movement through the tubing. Dynamic loads ...
    ... pressure, which is an indicator of the increase in potential energy of the fluid. The efficiency of the pump depends on its ability to convert mechanical energy into the potential energy of the fluid. Free gas in the fluid can negatively affect the pump's efficiency, especially at low pressure and ...