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Упит dcterms_subject_txt:top-down method

508 items

  • Determining the Availability of Continuous Systems at Open Pits Applying Fuzzy Logic

    Miljan Gomilanović, Miloš Tanasijević, Saša Stepanović (2022)
    This work presents a model for determining the availability of continuous systems at open pits by applying fuzzy logic and fuzzy inference systems. The applied model was formed by the synthesis of independent partial indicators of availability. The model is based on an expert system for assessing the availability of continuous mining systems. The availability of the system, as a complex state parameter, is decomposed into the partial indicators, reliability, and convenience of maintenance, and the fuzzy compositions, used ...
    системи, континуални систем експоатације, површински коп, рударство, расположивост, фази логика, max–min композиција, min–max композиција

  • An oilfield in Libya: A new model to enhance waste water disposal

    Dušan Danilović, Vesna Karović Maričić, Nori Elhaddad, Branko Leković (2016)
    нафта, лежишне воде, припрема

  • Mitigating hydrate formation in onshore gas wells: A case study on optimization techniques and prevention

    Milica Ješić, Bojan Martinović, Stefan Stančić, Miroslav Crnogorac, Dušan Danilović (2023)
    Gas wells, particularly those situated onshore, play a vital role in the global energy sector by supplying a significant portion of natural gas. However, operational challenges, notably gas hydrate formation, pose substantial issues, leading to complications such as flowline blockages and unexpected well shutdowns. Gas hydrates, crystalline structures resembling ice, ...
    Gas Well, Gas Hydrate Formation, Well Modeling, Well Performance Optimization, Choke Position Adjustments, Methanol Injection

  • Assessments of effects of implementation of strategic plans for development of Belgrade District heating system

    Dejan Ivezić, Marija Živković, Aleksandar Madžarević, Miodrag Grujić (2020)
    The district heating system (DHS) is one of the key elements of the Belgrade energy system. Overview of the current state and basic characteristics of the DHS are presented in this paper. The focus is on the planned development of DHS and on the analyses of effects of realization of measures and projects defined by strategic documents related to DHS which are adopted by city authorities (Development Strategy of DHS and Strategy of Belgrade Development). Two exploratory scenarios were ...
    Daljinsko grejanje, LEAP, Primarni energetski faktor, Uvozna zavisnost, CO2 emisija

  • Development of an integrated model for open-pit-mine discontinuous haulage system optimization

    Miodrag Čelebić, Dragoljub Bajić, Sanja Bajić, Mirjana Banković, Duško Torbica, Aleksej Milošević , Dejan Stevanović (2024)
    equipment selection, mine mechanization, expert judgment, linguistic variables, MCDM, FAHP

  • Geoenvironmental Investigations at a Smelter Location in Bor (Serbia)

    Petar Papić, Zvonimir Milijić, Jana Stojković, Jovana Milosavljević, Maja Todorović, Marina Ćuk, Željko Kamberović (2014)

  • A necessary and sufficient condition for an algebraic integer to be a Salem number

    Dragan Stankov (2019)
    We present a necessary and sufficient condition for a root greater than unity of a monic reciprocal polynomial of an even degree at least four, with integer coefficients, to be a Salem number. This condition requires that the minimal polynomial of some power of the algebraic integer has a linear coefficient that is relatively large. We also determine the probability that an arbitrary power of a Salem number, of certain small degrees, satisfies this condition.
    Algebraic integer, the house of algebraic integer, maximal modulus, reciprocal polynomial, primitive polynomial, Schinzel-Zassenhaus conjecture, Mahler measure, method of least squares, cyclotomic polynomials

  • 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
    ... affected a lot in results about deposition depth, but also on choosing right frictional parameter in rheological model. Method One of well used rheological model is Voellmy method (Voellmy, 1955) firstly used in snow avalanche models, which means that is basically one-phase. It is assumed that the ...
    ... Empirical relationships for debris flows. Natural Hazards 19: 47-77. Savage SB, Hutter K (1989) The motion of a finite mass of granular material down a rough incline. Journal of Fluid Mechanics 199 (1): 177-215. Schraml K, Thomschitz B, Mcardell BW, Graf C, Kaitna R (2015) Modeling debris-flow ...
    ... like the conservation of mass, momentum and energy of bulk mixtures (Rickenmann, 2005). In this paper, results of RAMMS debris-flow dynamical method are tested, based on Voellmy (1955) approach, which was specially designed for snow avalanches (Bartelt, 2015; Christen et al., 2007; 2010a; 2010b) ...

  • Investigating distant effects of the Moesian promontory: Brittle tectonics along the western boundary of the Getic unit (East Serbia)

    Ana Mladenović, Milorad D. Antić, Branislav Trivić, Vladica Cvetković (2019)
    In this study, we report evidence for brittle deformation in a part of the Carpatho–Balkan orogen, which is explained in terms of effects of the rigid Moesian promontory of the European plate on fault kinematics in East Serbia. We focus on the westernmost part of the Getic Unit of the East Serbian Carpatho–Balkanides, i.e. the Gornjak–Ravanica Unit, located between two main thrusts that were repeatedly activated from Early Cretaceous to recent times. We combine a new data set on ...
    Getikum, Mezijska jedinica, Karpato-balkanski orogen, krte deformacije, Gornjačko-ravanička jedinica

  • VENTEX: An Expert System for Mine Ventilation Systems Analysis

    Ranka Stanković, Nikola Lilić, Ivan Obradović (1996)
    Analiza sistema za ventilaciju je komleksan proces, koji bazira na proračunu brojnih parametara, koji se odnose na: stanje mreže, provetrenost, stabilnost sistema, gubitke vazduha, klimatske uslove, gasno stanje, ugroženost od požara i opasne prašine. Navedeni problemi se uspešno rešavaju paketom SimVent, ali potpuno razumevanje i korišćenje dobijenih rezultata zahteva angažovanje iskusnog specijaliste iz oblasti ventilacije. Rešenje je nađeno u kreiranju ekspertnog sistema VENTEX, čija je baza znanja formalizacija ekspertskog znanja iz oblasti ventilacije rudnika. U radu je prikazana metodologija ...
    ekspertni sistem, ventilacija
    ... type, min- max value and cardinality the slot features a call for a specific method (Calculate Delta) which will be activated if the specified condition (IfNeeded) is met. It means that the CalculateDelta method will be activated if at any point the value of the slot is required and the slot ...
    ... takes the form of IF-THEN rules. An example of such a method is CalcEstimateVN which estimates the state of the ventilation network on basis of several parameters and their mutual relationships /Fig. 7/. Figure 7. The CalcEstimateVN Method Since all rules in the system do not have to be related ...
    ... y, during system operation. An example, if the modification of the WPlaceVM rule is given in /Fig. 10/. Figure 10. The WPlace:WPValueVM Method The interface developed for VENTEX in KAPPA- PC fully exploits the GUI (graphical user interface) technology available for MS Windows applications ...

  • A Model for Determining Fuzzy Evaluations of Partial Indicators of Availability for High-Capacity Continuous Systems at Coal Open Pits Using a Neuro-Fuzzy Inference System

    Miljan Gomilanović, Miloš Tanasijević, Saša Stepanović, Filip Miletić (2023)
    This paper presents a model for determining fuzzy evaluations of partial indicators of the availability of continuous systems at coal open pits using a neuro-fuzzy inference system. The system itself is a combination of fuzzy logic and artificial neural networks. The system availability is divided into partial indicators. By combining the fuzzy logic and artificial neural networks, a model is obtained that has the ability to learn and uses expert judgment for that learning. This paper deals with the ...
    системи, континуални системи експлоатације (роторни багер-транспортер-дробилично постројење), рударство, расположивост, меко рачунарство, фази логика, ANN, ANFIS

  • Geostatički proračuni sanacije klizišta šipovima

    Slobodan Ćorić, Dragoslav Rakić, Dušan Berisavljević (2019)
    U ovom radu su, polazeći od rezultata geotehničkih istraživanja, prikazani geostatički proračuni sanacije klizišta vertikalnim šipovima. Metodologija proračuna je složena, jer podrazumeva interakciju klizišta i stabilizirajućih šipova. Stoga se simultano analiziraju stabilnost klizišta i stabilnost šipova. Prilikom određivanja bočne otpornosti tla oko šipova koristi se metoda Brinč Hansena koja uzima u obzir trodimenzionalne uslove u tlu i može da se primeni u složenim geološkim uslovima koji su česti u Srbiji. Analize stabilnosti klizišta vrše se odgovarajućim metodama granične ravnoteže. ...
    sanacija klizišta, interakcija klizišta i šipa, bočna otpornost šipova, stabilnost klizišta i šipova
    ... landslide stability analysis and pile stability analysis are carried out simultaneously.The lateral resistance of piles is calculated by Brinch Hansen method. It includes three-dimensional effects of surrounding soil and can be applied in complex geological conditions which are very often in Serbia. The ...
    ... vertikalnim šipovima. okolnog su. To se može da uradi na Ito, et al, 1975; Tomlinson, 1980) Hansen, 1961) je 1). Figure 1. Brinch Hansen’s method 295 Ома metoda зе одло05! па krute vertikalne Чроуе koji, род dejstvom sile H, гобтаји oko tačke O. Veličina bočnih pritisaka от, koja uzima ...

  • Numerical modeling of Selanac debris flow propagation using SPH code

    Jelka Krušić, Biljana Abolmasov, Miloš Marjanović, Manuel Pastor, Saeid M. Tayyebi (2021)
    The Selanac debris flow is a very huge event triggered after extreme rainfall caused by Cyclone Tamara activity in the Republic of Serbia in May 2014. The Selanac case study was already modelling in different programs using Voellmy rheology assumptions like RAMMS software. In this paper research are focusing particularly on the process of debris flowing from initiation zone to main deposition area using Geoflow SPH two-phase model considering frictional rheology law. Main rheological parameters are back-calculated using also ...
    debris flow, modelling, SPH code, DEM
    ... CARTAGENA, COLOMBIA- JUNE 15th-19th-2020 1 INTRODUCTION Debris flows occur usually after saturated, mainly poorly sorted material, started to flow down the slope as a result of motion of solid and fluid phase. Different mechanisms, rheological and numerical models are used in this area of research ...
    ... than the measured run-out distance obtained by the simulation model. Selanačka river transported material about 1 km longer, making instabilities down the river valley, which is likely due to the fact that it already had significant momentum upstream to begin with (torrential floods of its tributaries ...
    ... relationships for debris flows’’. Natural Hazards 19: 47-77. Savage, S.B., Hutter, K. (1989). ‘’The motion of a finite mass of granular material down a rough incline’’. Journal of Fluid Mechanics 199 (1): 177-215. Takahashi, T. (2007). ‘’Debris Flow: Mechanics, Prediction and Countermeasures’’ ...

  • Analysis of a simplified model for determining rock mass oscillation velocity at the Kovilovača open pit

    Suzana Lutovac, Miloš Gligorić, Jelena Majstorović, Luka Crnogorac (2023)
    ... models, using the values obtained by experimental measurements [6]. Model 1 – Determining the parameters by applying the least square method. The Least Square Method is mainly used to obtain the parameters K and n which represents a common model. Model 2 — Determining the parameters through the ...
    ... velocity equation defines velocity alteration of rock mass oscillation depending on distance, explosive amount, properties of rock material and blasting method. The equation, defined in this way, offers the possibility to determine the seismic effect of blasting towards a structure, whereby the connection ...
    ... elastic waves C, = 2852.67[m/ s] ; = 62.46[GN/m2], • dynamic elasticity modulus FE„ lin • „dynamic Poisson' ratio //„„ — 0.39|iGN/m2] . 6.2 Method of blasting in the open pit Kovilovača Measurements of seismic shocks in the open pit Kovilovača were performed during blasting, conducted for the ...

  • 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
    ... INSTRUCTION 338 Table 1.Required values of compaction and degree of unevenness [1:12-12] Type of Planum of the railway /on top of the protective layer / Planum of the railway /on top of the transition layer/ railways Rc* Ev2 N/mm2 Degree of unevenness Evd N/mm2 Rc* Ev2 N/mm2 Soil groups by AC ...
    ... European countries, as follows: In 2006, Instructions 338 were adopted for the control of compaction of the substructure of railway tracks by the dynamic method with a light falling weight (Light Weight Deflectometer) device on the JŽ railway network. In 2012, the Regulations on the design of reconstruction ...
    ... often lead to the degradation of the substructure, which results in the need to repair and reduce the speed. It is an indisputable fact that this test method is used as faster one in the world, but it is carried out with other tests: determination of Dpr, water content, correlation relations Ev2/Ev1, c ...

  • Characterization of biochar surface functional groups

    Marija Ilić, Vesna Pavelkić, Aleksandar Lolić, Branko Leković (2021)
    In this work, biochar originating from paper fibres was examined. Biochar was prepared via pyrolysis method at 550°C. Oxygen-containing functional groups on biochar surface were determined. The surface functional groups of biochar were analysed by Fourier transform infrared spectroscopy. The amount of oxygen-containing functional groups was performed with Boehm titration. The total acidity of biochar was mostly attributed to carboxylic and lactonic groups.
    biochar, surface functional groups, spectroscopy

  • Mineral and Thermal Waters of Serbia: Multivariate Statistical Approach to Hydrochemical Characterization

    Maja Todorović, Jana Štrbački, Marina Ćuk, Jakov Andrijašević, Jovana Šišović, Petar Papić (2016)

  • Synthesis and characterization of high-pressure and high-temperature sphene (CaTiSiO5)

    Jelena Pantić, Vladimir Urbanovich, Vesna Poharc-Logar, Bojan Jokić, Marija Stojmenović, Aleksandar Kremenović, Branko Matović (2014)
    Sphene (CaTiSiO5), a calcium titanosilicate ceramic has been prepared from a powder mixture of CaCO3, TiO2 and SiO2 using vibro-milling for homogenization and activation of precursors. During the highpressure and high-temperature synthesis (HPS) process at 4 GPa and 1,200 °C, sphene undergoes into phase transition, from room-temperature phase P21/a to high-temperature phase A2/a. Evidence of that structural phase transition is given in this paper using infrared, Raman spectroscopy and X-ray powder diffraction. Rietveld refinement was employed to get the ...
    Sphene, Phase transition, Raman spectroscopy, X-ray diffraction, SEM, IR

  • 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
    ... It is well known that there are two main ways of producing nanocrystals: top-down and bottom-up. However, because of poor solubility in organic solvents, the bottom-up method was excluded in this case [15]. Among many top-down techniques, wet media milling is considered optimal early in pharmaceutical ...
    ... organic molecules from undercooled melts. J. Pharm. Sci. 2010, 99, 3787–3806. [CrossRef] 15. Van Eerdenbrugh, B.; Van den Mooter, G.; Augustijns, P. Top-down production of drug nanocrystals: Nanosuspension stabiliza- tion, miniaturization and transformation into solid products. Int. J. Pharm. 2008, 364 ...
    ... DK-I-60-3 in the eluates was determined by LC-MS/MS method. From the concentration data, the pharmacokinetic parameters were calculated by “PK Functions for Microsoft Excel” (https://www.pharmpk.com/soft.html, accessed on 1 June 2021). 2.2.5. Analytical Method For the determination of DK-I-60-3 in all experiments ...

  • Primena termografije u rudarstvu

    Stevan Đenadić, Vesna Damnjanović, Predrag Jovančić, Dragan Ignjatović, Dragutin Jovković, Filip Miletić (2019)
    Danas, gotovo da nema oblasti u nauci i tehnici u kojoj se Infracrvena termografija ne primenjuje kao metoda za lociranje i praćenje zagrejanih objekata ili tela, beskontaktnu procenu temperature površina, i nedestruktivno ispitivanje materijala. U radu su prikazane mogućnosti i perspektive primene ove metode u oblasti rudarstva.
    infracrvena termografija, rudarstvo, monitoring
    ... Infrared thermography is not used as a method for locating and monitoring heated objects or bodies, contactless surface temperature estimation and non-destructive material testing. This paper presents the possibilities and prospects of applying this method in the field of mining. Key words: ...