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827 items

  • Metodologija proračuna sanacije klizišta šipovima

    Slobodan Ćorić, Dragoslav Rakić, Stanko Ćorić, Dušan Berisavljević (2022)
    Klizišta u Srbiji, u najvećem broju slučajeva, jako zavise od geoloških uslova u terenu i svako klizište ima svoje specifičnosti koje moraju da se odrede geotehničkim istraživanjima. Stoga su u radu prvo prikazane osnovne karakteristike klizišta u Srbiji, kao i postupci njihovog istraživanja. Zatim su prikazani proračuni sanacije klizišta vertikalnim šipovima. Metodologija proračuna je složena, jer podrazumeva interakciju klizišta i stabilizirajućih šipova. Prilikom određivanja bočne otpornosti tla oko šipova koristi se metoda Brinč Hansena koja uzima u obzir trodimenzionalne ...
    klizišta, geotehnička istraživanja, bočna nosivost šipova, interakcija klizišta i šipa, analiza stabilnosti

  • Metodologija određivanja vremena i putanje zagađivača na primeru zaštite izvorišta podzemnih voda

    Dušan Polomčić, Dragoljub Bajić, Vesna Ristić Vakanjac, Jelena Ratković, Marina Čokorilo Ilić (2018)
    Analiza vremena putovanja potencijalnog zagađivača do bunara izvorišta podzemnih voda predstavlja veoma bitan segment kod upravljanja i zaštite podzemnih voda. Ova metodologija se zasniva na simulaciji kretanja nereagujuće čestice sa podzemnim vodama i poroznom sredinom (“idealna” čestica). Rezultati hidrodinamičkog modela, kojim se vrši simulacija režima podzemnih voda, predstavljaju osnovu za model praćenja “idealne” čestice. Postoje različiti softveri koji se koriste u hidrogeološkoj praksi za analizu problema zagađivača. U ovom radu korišćen je numerički kod Modpath, dok je za simulaciju ...
    upravljnje podzemnim vodama, zaštita podzemnih voda, hidrodinamički model, metoda praćenja „idealne“ čestice, modflow, modpath.

  • Surface functional groups and degree of carbonization of selected chars from different processes and feedstock

    Marija Ilić, Franz-Hubert Haegel, Aleksandar Lolić, Zoran Nedić, Tomislav Tosti, Ivana Sredović Ignjatović, Andreas Linden, Nicolai D. Jablonowski, Heinrich Hartmann (2022)
    The knowledge ofthe structural and chemical properties of biochars is decisive for their application as technical products. For this reason, methods for the characterization of biochars that are generally applicable and allow quality control are highly desired. Several methods that have shown potential in other studies were used to investigate two activated carbons and seven biochars from different processes and feedstock. The chars were chosen to cover a wide range of chemical composition and structural properties as a hardness ...
    Biougalj, različiti procesi dobijanja, različite sirovine, površinski aktivne grupe, x-ray, FT-IR,XPS
    ... of K2p. https://doi.org/10.1371/journal.pone.0277365.t006 corresponds to the abundance found by chemical analysis and by XRD. The deviation of the O/C ratio from XPS and element analysis (Fig 2) was largest for the activated carbons and PW?700g. The lower O/C ratio for AC2 obtained by XPS can ...
    ... 100%) and the determination of ash forming elements. This complete analysis is the base for understanding the properties of the chars. In special cases, as for the presence of phosphoric acid in AC2, additional chemical analysis might be necessary to elucidate the true composition. X-ray diff ...
    ... spectroscopic methods was found to be suitable for the quality control of all types of chars. The most valuable results were obtained by chemical analysis that, however, required the complete determination of the main elements, including that of oxygen, and of inorganic components for adequate results ...

  • 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
    ... Systems, vol 128. Springer. [10] Mile Savkovic, Milomir Gasic, Miodrag Arsic, and Radovan Petrovic. Analysis of the axle fracture of the bucket wheel excavator. Engineering Failure Analysis, 18(1):433 – 441, 2011. ...
    ... and overhauls are unable to manage unexpected future events physiologically embedded in a complex system [3]. State of the art for static analysis and testing in the industry has also not yet proved to be able to provide those capabilities [4]. Using a complex maintenance operation in the ...
    ... operation is motivated by the impact of its downtime both from a technical perspective and from a financial perspective. Figure 2 shows a Pareto analysis of the BWE systems ranked by failure frequency/cost ratio. The first group of systems are the bearings in the gearbox. In theory, designed for ...

  • Analiza pouzdanosti dozera angažovanih na površinskim kopovima RB Kolubara

    Filip Miletić, Dragan Milčić, Miloš Tanasijević, Miloš Milovančević (2021)
    U radu je izvršena uporedna analiza pouzdanosti transportnih sistema dozera koji rade na površinskim kopovima Rudarskog basena Kolubara. Period za koji je vršena analiza je prvih deset godina eksploatacije. Efikasnost tehnološkog procesa na otkopavanju korisne mineralne sirovine i otkrivke u velikoj meri zavisi od rada dozera. Iskorišćene su matematičke metode za aproksimaciju i identifikaciju zabeleženih vremena u radu, kako bi se dobili analitički pokazatelji pouzdanosti. Na ovaj način se bitno podiže kvalitet upravljanja procesom eksploatacije i održavanja mašina na ...
    dozeri, pouzdanost, kolubarski ugljeni basen

  • Design of the Opencast Coal Mine Drmno Dewatering System

    Vladimir Pavlović, Dušan Polomčić, Tomislav Šubaranović (2014)
    Development of mining in the opencast mine Drmno from Kostolac basin in Serbia is carried out in the increasingly complex geological and hydro geological conditions with the decline of the coal seams to the alluvial part of Europe's largest river Danube. Greater depth and inflow of groundwater significantly increase costs for dewatering facilities construction with the requirement for optimizing of this more and more important surface mining process. Making decision on screen construction in the opencast mine with redesign ...
    dewatering system, groundwater, hydrodynamic model, dewatering wells, screen, reliability, environmental effects.

  • Human factor risk management procedures applied in the case of open pit mine

    Snežana Kirin, Aleksandar Sedmak, Wei Li, Miodrag Brzaković, Igor Miljanović, Ana Petrović, Simon Sedmak (2021)
    Risk management aims to provide a controlled work environment to ensure the safe operation of the high-risk systems. It is a dynamic process which work in a continual state of change. The issue of human factor risk and rules and regulations in open pit mine is a main focus of this paper in order to develop predictive models of behavior of workers in relation to compliance with the procedures and rules. Presented survey was conducted in open pit coal ...
    Upravljanje rizikom, ljudski faktor, bager sa kašikom, metod konačnih elemenata

  • Analiza primene višekriterijumskih metoda u optimizaciji izbora hidruličnih bagera na površinskim kopovima uglja

    Stevan Đenadić, Predrag Jovančić, Dragan Ignjatović, Filip Miletić, Ivan Janković (2019)
    Hidraulični bageri primenjuju se u različitim oblastima privrede a najzastupljeniji su u građevinarstvu i rudarstvu. Na površinskim kopovima sa kontinualnim sistemima, klasifikuju kao pomoćna mehanizacija a na površinskim kopovima sa diskontinualnim sistemima, kao osnovna mehanizacija. Kako je u oba slučaja njihova primena neizostavna, važno je izvršiti adekvatnu analizu postojećih podataka, u cilju optimizacije izbora tipa hidrauličnog bagera u odnosu na uslove rada datog površinskog kopa. U radu su opisane različite višekriterijumske metode koje su korišćene za analizu hidrauličnih bagera. ...
    višekriterijumske metode, površinski kop uglja, pomoćna mehanizacija, hidraulični bager

  • The correlation of Upper Miocene lithostratigraphic units of the southern part of the Pannonian basin

    Filip Anđelković, Dejan Radivojević (2019)
    gornji miocen, litostratigrafske jedinice, formacije, Panonski basen

  • Towards Automatic Definition Extraction for Serbian

    Ranka Stanković, Cvetana Krstev, Rada Stijović, Mirjana Gočanin, Mihailo Škorić (2021)
    U radu su prikazani preliminarni rezultati automatske ekstrakcije kandidata za definicije rečnika iz nestrukturiranih tekstova na srpskom jeziku u cilju ubrzanja razvoja rečnika. Definicije u rečniku Srpske akademije nauka i umetnosti (SANU) korišćene su za modelovanje različitih tipova definicija (opisnih, gramatičkih, referentnih i sinonimskih) koje imaju različite sintaksičke i leksičke karakteristike. Korpus istraživanja sastoji se od 61.213 definicija imenica, koje su analizirane korišćenjem morfoloških e-rečnika i lokalnih gramatika implementiranih kao pretvarači konačnih stanja u paketu za obradu korpusa otvorenog ...

  • Bioleaching Process for Copper Extraction from Waste in Alkaline and Acid Medium

    Ivica Ristović, Darina Štyriaková, Iveta Štyriaková, Jaroslav Šuba, Emilija Širadović (2022)
    Flotation wastes are becoming a valuable secondary raw material and source of many metals and semimetals worldwide with the possibilities of industrial recycling. The flotation tailings contain oxide and sulfide minerals that have not been sufficiently stabilized and form acidic mine waters, which in turn contaminate groundwater, rivers, and reservoi6sediments. An effective way to recycle these mine wastes is to recover the metals through leaching. While the focus is on acid bioleaching by iron- and sulfur-oxidizing bacteria, alkaline leaching, ...
    bakar, alkalno, kiselo bioluženje, sekundarne sirovine

  • Analiza sistema odvodnjavanja površinskog kopa Drmno od podzemnih voda sa severnim savršenim ekranom

    Tomislav Šubaranović, Dušan Polomčić, Vladimir Pavlović (2019)
    Izrada nesavršenog ekrana do drugog sloja uglja na površinskom kopu Drmno, pored zadržavanja postojećih standardnih metoda odvodnjavanja od podzemnih voda linijama bunara, predviđena je poslednje decenije u celokupnoj rudarskoj projektnoj dokumentaciji. Iz objektivnih i subjektivnih razloga njegova realizacija nije ostvarena do danas. U međuvremenu je, uz dodatna geološka istraživanja i promenu dinamike i parametara sistema površinske eksploatacije, došlo do određenih značajnih prostornih promena geoloških i rudarskih uslova u eksploatacionom polju. Ovo je omogućilo preliminarno inoviranje pristupa procesu i konceptu ...
    podzemne vode, odvodnjavanje, bunari, ekran, dinamika, troškovi

  • Complex geophysical survey on solving the problem of water loss in the karst terrain reservoir

    Branislav Sretković, Dejan Vučković (2023)
    Geophysical surveys in karst terrain are always a specific challenge. Each of them requires a careful consideration of the problem, specific conditions on the ground, the selection of adequate methods applicable in that specific and unique karst area. But they should have one thing in common: a complex approach and looking at the problem from wider to narrower, with a gradual narrowing of the investigation area, increasing the spatial precision and resolution of the obtained data. On the example of ...

  • Analiza nosivosti vertikalno opterećenog šipa za potrebe izgradnje petlje „Merošina 1“ na autoputu E-80 deonica: Niš – Merošina

    Dragoslav Rakić, Nikola Božović, Miloš Stevanović, Milan Bogdanović (2023)
    U Srbiji je počela izgradnja autoputa E-80 koji će predstavljati saobraćajno čvorište zapadnog Balkana i biće deo glavne regionalne transportne mreže jugoistočne Evrope. Njegova ukupna dužina kroz Srbiju iznosi 77 km, a prva deonica u dužini od 5.5 km je završena i puštena u saobraćaj krajem jula 2023. god. To je prva od četiri deonice Sektora 1 čija je dužina 32.65 km. U sklopu petlje „Merošina 1“ izgrađen je nadvožnjak koji je oslonjen na devet stubnih mesta na međusobnom ...
    petlja Merošina 1, šip, probno opterećenje šipa, projektni pristup, granična stanja

  • Geotechnical Conditions for Construction of Savski Trg Metro Station as a Part of the Belgrade Metro Line One

    Nemanja Stanić, Dragoslav Rakić, Josip Isek, Slavoljub Simić (2024)
    In order to solve serious traffic congestion in Belgrade, a number of studies regarding the Belgrade Metro construction have been carried out since 1973. However, only in 2019, the routes of the future metro lines 1 and 2 were defined as a part of the General Metro Construction Project. The lines are designed to intersect at the location of Sava Square, where an interchange metro station will be built. It represents a complex geotechnical structure consisting of three different ...
    metro station, geotechnical modelling, displacements

  • Adaptive neuro-fuzzy prediction of operation of the bucket wheel drive based on wear of cutting elements

    Filip Miletić, Predrag D. Jovančić, Milos Milovančević, Dragan Ignjatović (2020)
    The capacity of the rotor excavator depends largely on the operation of the subsystem for digging. There is a great contribution to the correct and sharp teeth when the capacity is the highest. In the function of time, the teeth become clogged due to abrasive wear, or changes in their geometric shape. To analyze the bucket wheel drive in depend on wear of the cutting elements in this study adaptive neuro fuzzy inference system (ANFIS) approach was implemented. ANFIS ...
    Pogon rotornog točka, habanje, rezni elementi, ANFIS
    ... horizontal and vertical forces were read. The measured vibrations in the axial direction have no pronounced influence, so they are excluded from the analysis. Measurements were made at the location of the inlet pair of the ex- cavator drive gearbox in the horizontal direction (transverse to the input shaft) ...
    ... automotive bush chain drive systems. Wear 2020:203193. [3] Mikołajczyk T, Nowicki K, Kłodowski A, Pimenov DY. Neural network approach for automatic image analysis of cutting edge wear. Mech Syst Sig Process 2017;88:100–10. [4] Liu K, Li XP, Rahman M, Liu XD. CBN tool wear in ductile cutting of tungsten carbide ...
    ... measured in both field experiments and laboratory tests. Wear 2015;328:149–59. [6] Kumar R, Dwivedi RK, Ahmed S. Wear characteristics and temperature analysis of alloy steel using self-developed wear testing machine. Mater Today 2019;18:2875–80. [7] Sellami A, Hentati N, Kchaou M, Kus R, Elleuch R, Chowdhury ...

  • Possibility of application of fuzzy logic for stability assessment of underground facilities

    Luka Crnogorac, Rade Tokalić, Đurica Nikšić, Saša Jovanović (2019)
    Rudnici sa podzemnom eksploatacijom uglja u Republici Srbiji deo su Javnog preduzeća za podzemnu eksploataciju uglja Resavica (JP PEU). U rudnicima kompanije JP PEU podzemne prostorije se trenutno grade tehnologijom bušenja i miniranja. Ova metoda, koja se koristi u srpskim rudnicima uglja, pokazala je svojom brzinom, efikasnošću, troškovima i drugim elementima da više nije prihvatljiva. Klasičan metod izgradnje podzemnih prostorija ne omogućava zadovoljavajuću produktivnost, jer se tehnološke operacije ovog metoda, bušenje i miniranje, izvode ručno i zahtevaju neprihvatljivo mnogo ...
    analiza, podzemna prostorija, mehanizovana izgradnja, rudnik

  • Termička zrelost organske supstance i naftno-matični potencijal istočne Hercegovine

    Nikoleta Aleksić (2021)
    Cilj istraživanja, obrade i interpretacije rezultata prikazanih u disertaciji je utvrđivanje termičke zrelosti organske supstance i naftno-matičnog potencijala sedimentnih stena na području istočne Hercegovine, primenom metoda pirolize Rock-Eval, organo-petrografskog proučavanja organske supstance u normalnoj svetlosti i fluorescenciji, koja je pored kvalitativne analize uključila posebno i refleksiju vitrinita. Osim toga, na osnovu organsko-geohemijskih analiza sagledane su karakteristike i poreklo ekstrahovanog bitumena metodom gasne hromatografije - masene spektrometrije, pri čemu su izvršene analize biomarkera kao geohemijskih indikatora. Tokom rada na doktorskoj ...
    organska supstanca, termička zrelost, matične stene, naftni potencijal, refleksija vitrinita, piroliza Rock-Eval, biomarkeri, Karbonatna platforma, istočna Hercegovina

  • Mineralogy, chemistry, and distribution of selected trace elements in coal and shale from the Ibar Basin (South Serbia)

    Željana Novković, Nenad Nikolić, Nevena Andrić-Tomašević, Violeta Gajić, Mercedes Suárez, Emilia García-Romero, Vladimir Simić, Dragana Životić (2024)
    Ibarski basen, kameni ugalj, glinci, mineralogija, elementi u tragovima

  • Geochemical evaluation of dolostone deposits in Montenegro: Implications for potential industrial applications

    Darko Bozovic, Vladimir Simic, Dragan Radulovic, Slobodan Radusinovic, Vesna Matovic, Anja Terzic (2024)
    This study presents a unique model for assessing the dependability of continuous parts of combined systems in open-pit mining through the application of fuzzy logic. Continuous sub-systems as part of the combined system of coal exploitation in surface mines have the basic function of ensuring safe operation, high capacity with high reliability, and low costs. These subsystems are usually part of the thermal power plant’s coal supply system and ensure stable fuel supply. The model integrates various independent partial ...
    примарне сировине, минералогија, физичко-механичка својства, технолошка својства, наука о материјалима