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Упит dcterms_subject_txt:borehole pressure

172 items

  • Синтеза и карактеризација керамике на бази сфена

    Jelena R. Pantić (2015-07-10)
    Механохемијска активација стехиометријске смеше реактаната TiO2, SiO2 и CaCO3 показала се као веома успешна и једноставна метода за добијање сфена (CaTiSiO5). На основу мерења релативних густина свих синтерованих узорака установљено је да максималну густину од 93,9 % имају узорци који су активирани 30 минута и синтеровани на 1200 °С. Микроструктурном анализом, тј. анализом слика синтерованих узорака активираних 30 минута, које су добијене скенирајућом електронском микроскопијом, опажа се бимодална расподела величине зрна, са просечном величином од 3 μm, односно 5 ...
    сфен, механохемија, Ритвелдова метода, оптичка спектроскопија, микроструктурна анализа, фазна трансфоpмација, чврсти раствори
    ... high pressure phases, mechanochemicaly activated sphene was treated by high pressure - high temperature synthesis process. Samples were sintered at pressure of 3.5±0.2 and 4.0±0.2 GPa and at temperature of 1100 and 1200±50 °C. The highest achieved densitу have samples sintered with pressure of ...
    ... at high pressure and high temperature. Am Mineral 85: 1465-1473. Kunz M. and Brown I.D. (1994) Out of center distortions around octahedrally coordinated d0-transition metals. J Solid State Chem 115: 395-406. Kunz M., Xirouchakis D., Lindsley D.H. and Hauserman D. (1996) High- pressure phase ...
    ... electron microscope, suggesting that the particles are composed of packed crystallites. Also, reduction of particle size occurred during high pressure compaction. Keywords: ѕphene, mechanochemistry, Rietveld refinement, optical spectroscopy, microstructural analysis, phase transition, solid ...

  • A Knowledge-Based Approach to Mine Ventilation Planning in Yugoslav Mining Practice

    Nikola Lilić, Ivan Obradović, Ranka Stanković (2002)
    Ventilation system analysis is a complex process based on the calculation and analysis of numerous parameters. These problems can be successfully solved by the SimVent numerical package, but a full understanding and use of the obtained results require the involvement of an experienced specialist in the ventilation field. The solution was found in the creation of a hybrid system INVENTS, whose knowledge base represents a formalization of the expert knowledge in the mine ventilation field. In this paper, we ...
    ... the pressure of the booster fan varies in wide limits of given values from 10 Pa to 600 Pa. The variable related to the location of the fan takes values from a predetermined set of branches where the introduction of booster fans is permitted (branches 1, 3, 5, 7, 9, 14, 15, 16). The pressure of the ...
    ... global structure of the mathematical model used as the basis for SimVent is composed of the following: (i) a block for the analysis of air flow and pressure distribution in the ventilation network, (ii) a block for the analysis of climate conditions in mine workings, (iii) a block for temperature and ...
    ... system state of the “Soko” mine the following measurements were initially undertaken: temperatures of the dry and wet bulb thermometer and barometric pressure in mine ventilation nodes were measured, as well as the air flow volumes in network branches. The data obtained were used as input for the ResNet ...

  • 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
    ... measuring range of 0 to 250 kN of the compressive force and accuracy class 0.5%. Water absorption (determination of water absorption at atmospheric pressure) was determined according to EN 13755 and was conducted on the prisms with dimensions 40 mm × 40 mm × 160 mm. Prisms were firstly dried at the temperature ...
    ... The percentage difference of masses of a saturated and a dry sample, and the mass of the dry sample represents the water absorption at atmospheric pressure. Water absorption (determination of water absorption coefficient due to capillary action of hardened mortar) was performed according to standard ...
    ... a metal, cylindrical vessel with a capacity of 8 dm3. Air content in fresh concrete was determined according to standard EN 12350-7 by using the pressure method. For testing, an apparatus was used which consisted of a metal cylindrical vessel with a capacity of 8 dm3 and a special lid with a pump and ...

  • From post-disaster landslides inventory to open landslides data

    Biljana Abolmasov, Miloš Marjanović, Uroš Đurić, Jelka Krušić (2021)

  • 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
    ... Phil Wilson explained the HP [6]. As the main factors geographical and environmental restrictions were taken, the secondary factors were reservoir pressure, productivity index, the characteristics of reservoir fluids, and well productivity characteristics. The importance of this work is reflected in ...
    ... technical limitations of the methods applied. The parameters considered are: pump volume capacity, the depth in combination with the desired dynamic pressure at the bottom of the well, the deviation of the well, and characteristics of the reservoir. The second step further reduces the choice, based on ...
    ... parameters were not considered [11–14]. Input parameters can be grouped into three groups: I. Characteristics of reservoir, well and fluid (depth, pressure, production, and technical limitations of artificial lift methods) Energies 2020, 13, 1758 4 of 15 II. Conditions in which the well operates ...

  • Natural two-dimensional pyrophyllite: Nanoscale lubricant, electrical insulator and easily-machinable material

    Borislav Vasić, Radoš Gajić, Ivana Milošević, Žarko Medić, Marina Blagojev, Marko Opačić, Aleksandar Kremenović, Dejan Lazić (2022)
    Pyrophyllite, with the chemical formula Al2Si4O10(OH)2, is a naturally occurring and abundant van der Waals mineral belonging to the group of phyllosilicates. It is very soft, layered crystal used for sculpting and an excellent electrical and thermal insulator aimed for the operation at high pressure and temperature. Here, for the first time, two-dimensional (2D) pyrophyllite obtained by both mechanical and liquid phase exfoliation is presented and investigated at the nanoscale. The layered structure provides low friction coefficient of around ...
    Atomic force microscopy, Insulating properties, Nanofriction and wear, Natural two dimensional materials, Phyllosilicates, Pyrophyllite

  • Curcumin nanonization using an alternative small-scale production unit: selection of proper stabilizer applying basic physicochemical consideration and biological activity assessment of nanocrystals

    Ines Nikolić, Jelena Antić-Stanković, Dragana Božić, Danijela Ranđelović, Bojan Marković, Dominique Jasmin Lunter, Aleksandar Kremenović, Miroslav Savić, Snežana Savić (2020)
    As the number of poorly soluble drugs is increasing, nanocrystals have become very interesting due to wide range of application possibilities. Curcumin was used as a model active ingredient in this work. Even though it has many proven positive effects, due to its physicochemical issues, its possibilities have not been fully exploited. The goal of this work was to select optimal conditions for a top-down method for curcumin nanosuspension production, and to perform their comprehensive characterization applying complementary methodologies: ...
    nanocrystal, curcumin, top-down method, wetball milling

  • Influence of Ag doping on the morphological and magnetic properties in CuO nanopowders

    Maria Čebela, Uroš Čakar, Vesna Lojpur, Maja Milošević, Sanja Krstić, Vladimir Dodevski, Milena Rosić (2023)
    ... hydroxide occurred. Prepared powders were calcinated at 700 "C for 2 h. The diffraction pattern was recorded at room temperature and atmospheric pressure without of any re-heating of the sample. The Rietveld method for fitting refinement procedure was performed which showed the incorporation of ...

  • Uticaj utiskivanja gas-lift gasa na prenos mase i toplote

    Branko Grubač (2019)
    Nakon uvođenja kontinualnog gas-lifta, primećen je porast proizvodnje tečnog naftnog gasa, TNG, u postrojenju za preradu gasa, kao jednog od finalnih proizvoda dobijenog iz fluida gaso kondenzatnih i rastvorenog gasa iz naftnih bušotina. Pretpostavljeno je da se prisustvom gas-lift gasa uspostavlja drugačija ravnoteža faza u odnosu na slučaj bez gaslifta, te da je gas-lift gas stripovao propan i butane iz tečne u parnu fazu, što je dovelo do povećanja prinosa TNG-a. Napravljen je model bušotine koja radi u kontinualnom gas-liftu ...
    gas-lift, modelovanje bušotine, prenos mase i toplote, taloženje parafina
    ... verification was done by comparing the results of the PLT measurements, through the pressure and temperature profiles in the gas-lift well. The results showed that the difference between the measured and calculated pressure/temperature profiles is reduced by increasing the number of pipe segments. Based ...
    ... [44] X. Zhao, J. Xu, Numerical simulation of temperature and pressure distribution in producing gas well, World journal of modelling and simulation, Vol. 4, str 94-103, (2008) [45] O. Cazares-Candia, M. Vasquez-Cruz, Prediction of pressure, temperature, and velocity distribution of two-phase flow ...
    ... Technology, str 1003-1008, (1983) [69] B. Shannak, Frictional pressure drop of gas liguid two-phase flow in pipes, Nuclear Engineering and Design, Vol. 238, str 3277-3284, (2008) [70] T. Russell, A. Etchells, R. Jensen, R. Arruda, Pressure drop and holdup in stratified gas-liquid flow, AiChE Journal ...

  • Anisotropic grossular–andradite garnets: Evidence of two stage skarn evolution from Rudnik, Central Serbia

    Bojan Kostić, Danica Srećković-Batoćanin, Petyo Filipov, Pavle Tančić, Kristijan Sokol (2021)
    This paper presents LA-ICP-MS data for garnets from the Rudnik skarn deposit (Serbia), which range from Grs45–58Adr40–52Alm2–3 in the core and Adr70–97Grs2–29Sps1 in the rim displaying anisotropy and zoning. In spite of wide compositional variations the garnets near the end-member of andradite (Adr > 90) are generally isotropic. Fe-rich rims exhibit LREE depletion and flat HREE pattern with weak negative Eu anomaly, including higher As and W contents. On the other side, the Fe-poorer core shows flat REE pattern ...
    grandite, garnets, skarn, Rudnik
    ... in the contact-metamorphic aureole around the Rudnik orefield. The analysed sample SN-310 was collected from the borehole at the 289 m depth. The units discovered by the borehole start with coarse-grained conglomerate containing fragments/clasts from quartzite, chert and altered peridotites. ...
    ... bodies. The first sample SN-313 comes from the borehole in the shal- low massive quartz latite intrusion north-west from Rudnik Mt. Another sample, SN-330, was taken from a quartzlatitic sill/dyke about 25 m thick, which has also been accessed by borehole. These quartz latites cut Upper Cretaceous sediments ...
    ... by metasomatism or change in temperature and pressure conditions. However, the small contact-metamorphic aureole, like that on Rudnik Mt. does not display any physical evidence for major variation and does not testify to large changes of pressure and temperature. In fact, garnet has kept growing ...

  • 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
    ... characteristics Length, km 18,422 Operating pressure for industry (medium pressure) 4–16 bar Length of distribution network at medium pressure ~1470 km Operating pressure for households (low pressure) <4 bar Length of distribution network at low pressure ~16,950 km * maximal daily capacity guaranteed ...
    ... security declined with the stabilization of oil prices in the 1980s and 1990s, it became topical again in the 2000s because of the high demand in Asia, pressure to modernize and decarbonize energy systems and problems with gas supplies in Europe [5]. The definition of energy security has changed over the ...
    ... security declined with the stabilization of oil prices in the 1980s and 1990s, it became topical again in the 2000s because of the high demand in Asia, pressure to modernize and decarbonize energy systems and problems with gas supplies in Europe [5]. The definition of energy security has changed over the ...

  • Correlation Between Dynamic CBR and Compaction and Bearing Capacity of Pavement Foundation Layers

    Milan Bogdanović, Snežana Bogdanović, Dragoslav Rakić, Irena Basarić Ikodinović (2024)
    This paper presents a dynamic California Bearing Ratio (CBRd) device that can be used on a prepared pavement foundation layer to obtain a certain parameter of the tested material in the laboratory and in situ in a direct and fast way. For the selected natural material (gravel), it is shown that the laboratory CBRd can be used to estimate the compaction and bearing capacity, because it correlates well with the parameters of the standard and modifed Proctor compaction tests. ...
    korelacija parametara, donji slojevi saobraćajnica, laboratorijska i terenska ispitivanja, dinamički kalifornijski indeks nosivosti CBRd
    ... Before the test started, the load transducer and the number gauge or transducer were set to zero. Sub- sequently, a preload corresponding to the pressure of 0.01 MN/m! for a plate diameter (d) of 300 mm was applied. The deformation modulus E,,-E,, was determined using the load-unload-load process ...
    ... one test. After performing SPLT and collecting the required data, the subgrade reaction modulus (K,) was calculated for each station using the pressure-settlement curve [12].In this process, certain items must be considered. Light-weight deflectometer The LWD is a portable device with a falling ...

  • Analiza softvera za projektovanje ESP sistema

    Aleksandar Sredojević (2024)
    U momentu kada pritisak na dnu bušotine nije dovoljan da savlada ukupne gubitke pritisaka od dna bušotine do separatora, proizvodnja pomoću ležišne energije nije više moguća i bušotina prestaje sa eruptivnim radom. Kako bi ponovo omogućili proizvodnju fluida iz bušotine, potrebno je primeniti neke od mehaničkih metoda eksploatacije. Najprimenljivije mehaničke metode eksploatacije su: gas lift (GL), dubinske pumpe sa klipnim šipkama (SRP), električne uronjene centrifugalne pumpe (ESP), zavojne pumpe (PCP) i hidraulične pumpe (HP). Jadna od tih metoda koja ...
    električna centrifugalna pumpa (ESP), proizvodnja fluida, mehaničke metode eksploatacije, Prosper, Pipesim
    ... TRANSFER OPTIONS Branch start: X-1- Reservoir. ' Inlet pressure 1817 bara ~| _ Overide heat transfer options: |} Branch end: (X-1- Wellhead utlet pressure" 24 bara d lInside film coefficient method: Kreith Default profile plot: — Elevation vs. pressure 7O |Liquidflowrate + Well survey data: FLUID RATIOS ...
    ... 'Gas Separator Method Enter Separator Efficiency s40| as Separator Eficency 100110 percent e Liquid Level Calculated r5i -| 0| Casing Head Pressure 1.1 BARa }i T 480| Allow Tapered ESPs No Number of Motors Number Of Stages 326 Voltage At Surface. 1000 Pump Wear Factor 0.05 'Gas DeRating ...
    ... CALCULATIONS (X-1.Out) || x se__|| s =O == | Calculation | InputData | Modified Sachdeva Choke Model Data TotalGOR |82.727. Sm3/Sm3 Predict Pressure Drop' Predict Choke Setting WaterCut | 50 percent Diameter Out (D3) | 62 InletPressure | 22.8. BARA Discharge Coefficent (cd) [0.5 InletTemperature ...

  • Strategic Environmental Assessment in the Application of Preventive Protection for Wind Farm Noise—Case Study: Maestrale Ring Wind Farm

    Boško D. Josimović, Aleksandar Cvjetić, Božidar Manić (2021)
    Determining the spatial position of wind turbines is the initial and most important phase in the development of a wind farm project. In this sensitive phase, all potential problems that may arise in the later stages of project development should be prevented by means of spatial and urban planning instruments. This makes it possible to achieve maximum use of the potential of wind in a particular space and, thus, fulfil the technical and economic requirements of the project while ...
    Energija,energetski inženjering i elektroenergetska tehnologija,obnovljivi izvori energije, održivost i životna sredina,električni i elektronski inženjering,kontrola i optimizacija,inženjering
    ... conventions listed in ISO 1996-1:2016 and ISO 1996-2:2017 [58]. Accordingly, all frequency-weighted levels of sound pressure are expressed in decibels (dB) (e.g., the sound pressure levels obtained during modeling using A-frequency weighting are expressed as LA (dB). The criteria for assessing ...
    ... farm on buildings and on the population was eliminated. 4. Discussion Although some authors [35,60–67] confirm that the levels of infrasound pressure emitted by wind turbines are significantly below the generally accepted threshold of hu- man hearing, which is why they cannot lead to negative ...
    ... assessment procedures, ISO 1996-2:2017 Acoustics—description, measurement and assessment of environmental noise—Part 2: Determination of sound pressure levels;nternational Organization for Standardization: Geneva, Switzerland, 2016. 59. ISO 9613-1:1993. Acoustics—Attenuation of sound during propagation ...

  • Low-temperature phase transition and magnetic properties of K3YbSi2O7

    Predrag Dabić, Volker Kahlenberg, Biljana Krüger, Marko Rodić, Sabina Kovač, Jovan Blanuša, Zvonko Jagličić, Ljiljana Karanović, Václav Petříček, Aleksandar Kremenović (2021)
    alkalni silikati elemenata retkih zemalja, fazni prelazi, magnetne karakteristike, razdvajanje kristalnog polja, silikati lantanica
    ... Imma symmetry (measured at 30 K). Furthermore, a pressure-induced phase transition in REE silicates with the apatite-type structure [REE4.67(SiO4)3O, hexagonal, P63/m] was reported recently (Zhang et al., 2012, 2013). The application of high pressure causes a tilt of the isolated SiO4 tetrahedra and ...
    ... the Jmma symmetry (measured at 30 K). Furthermore, a pressure-induced phase transition in REE silicates with the apatite-type structure [REE,¢7(Si0,)30, hexagonal, P63/m] was reported recently (Zhang et al., 2012, 2013). The application of high pressure causes a tilt of the isolated SiO, tetrahedra and ...
    ... and triggers a symmetry reduction from P63/m to P63. Notably, the pressure- induced phase transition in these apatite compounds is a reversible process. For potassium-containing rare-earth disilicates two struc- ture types have been described so far, which crystallize in the space groups P63/mcm ...

  • Fluid inclusion systematics in the Okoška gora polymetallic deposit

    Aleš Šoster, Miloš Velojić, Barbara Potočnik Krajnc, Matej Dolenec (2021)
    ... GEOLOGIJO Ljubljana 2021 јапак, M., Froitzheim, N., Luptak, B., Vrabec, M, & ultrahigh-pressure metamorphism of eclogites subduction in the Eastern Alps, Slovenia. • T. Linnemann, U., Ouzegane, K., Drareni, A., Hofmann 2011: Sands of West ...

  • 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

  • Spatial assessment of the areas sensitive to degradation in the rural area of the municipality Čukarica

    Natalija Momirović, Ratko Kadović, Veljko Perović, Miloš Marjanović, Aleksandar Baumgertel (2019)
    Nature and Landscape Conservation, Soil Science, Agronomy and Crop Science, Water Science and Technology

  • Evaluation And Perspectives Of Underground Coal Mines In Serbia

    Vladimir Milisavljević, Milena Lekić, Ivica Ristović, Vojin Čokorilo, Aleksandar Cvjetić (2017)
    ... reserves (criteria C1); • Geological conditions, such as faulting, seam inclination, block size, seam variation, roof and floor conditions, rock pressure and geo-mechanic conditions (criteria C2); • Mining hazards, such as gas, water, dust and potential for gas outbursts and spontaneous combustion ...

  • English for Geology Students. 2

    Lidija Beko (2023)
    Engleski jezik
    ... processes are also responsible for the formation of diamonds, a mineral with generally very high financial viability. Crystallising under very high pressure at depths of almost 200km below the Earth's surface, this form of carbon is carried to the surface via kimberlite pipes – naturally occurring ...