Претрага
218 items
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Structural and microstructural study of brookite based TiO2 nanocomposites with carbon black (C)
Structural and microstructural properties of TiO2-based nanocomposites with carbon black (C), synthesized by sol-gel-hydrothermal method, have been studied by XRPD and Raman scattering. Detailed size-strain analyses of XRPD and Raman scattering results are presented in order to investigate the influence of C content on brokite and anatase phase formation. The XRPD size-strain analyses have resulted in reliable structure and microstructure results for both anatase and brookite and their relative abundance ratio has been refined by Rietveld method. The brookite ...Aleksandar Kremenović, Mirjana Grujić-Brojčin, Nataša Tomić, Maja Šćepanović. "Structural and microstructural study of brookite based TiO2 nanocomposites with carbon black (C)" in The European Powder Diffraction Conference (EPDIC) Book of Abstracts, Šibenik, 31 May - 3 June 2022, EPDIC (2022) М34
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Correlation of uniaxial compressive strength with the dynamic elastic modulus, p –wave velocity and s –wave velocity of different rock types
Knowing mechanical properties of rocks incorporated with ultrasonic waves velocities investigations provide a secure basis for mine modelling. Uniaxial compressive strength, dynamic elastic modulus and ultrasonic waves velocities are just some of the rock properties that indicate on presence of discontinuities, stratification and fissures of rocks. Determining the relationship of these rock properties testing the rock samples that are corresponding to different rock types extracted from different mineral deposits represents the core of this study. In this paper, we ...Jelena Majstorović, Miloš Gligorić, Suzana Lutovac, Milanka Negovanović, Luka Crnogorac. "Correlation of uniaxial compressive strength with the dynamic elastic modulus, p –wave velocity and s –wave velocity of different rock types" in Underground mining engineering, Рударско - геолошки факултет - Београд (2019) М51
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Some continuous stress mixed formulations and inf-sup test
The most frequent motivation for the use of mixed methods is their robustness in the presence of certain limiting and extreme situations. At variance, the main goal of the present paper is to reconsider the use of mixed formulation as a tool for wider application, i.e., to study the stability of the proposed procedure treating problems in elasticity otherwise well suited for the solution by the usual displacement method.Computational procedure for the inf-sup test is outlined, and the results ...Mladen Berković, Dubravka Mijuca, Ines Grozdanović. "Some continuous stress mixed formulations and inf-sup test" in Computer Assisted Mechanics and Engineering Sciences, Instytut Podstawowych Problemów Techniki PAN (2001) М52
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Mine ventilation system planning using genetic algorithms
The most common problem in contemporary mining practice related to the planning and analysis of ventilation systems is the optimization of partially regulated air distribution in mine ventilation networks. This paper presents a two step optimization procedure for partly regulated air distribution in mine ventilation networks. The first step is the determination of air distribution in all branches using the well known Hardy-Cross method. In the second step the distribution and parameters of air flow regulators with minimum engaged ...coal, lignite, and peat; ventilation systems; coal mining; underground mining; ventilation; mathematical models; design; air flow; optimization; calculation methodsNikola Lilić, Ranka Stanković, Ivan Obradović. "Mine ventilation system planning using genetic algorithms" in 6. international symposium on mine planning and equipment selection, Ostrava (Czech Republic), 3-6 Sep 1997, A.A. Balkema, Rotterdam (Netherlands) (1997) М33
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Određivanje prostorne distribucije vrednosti hidrauličkih parametara izdani: primer površinskog kopa „Radljevo“
Najčešće se kalibracija hidrodinamičkih modela vršila manuelno - „probanjem“ sa različitim vrednostima hidrauličkih parametara i hidrauličkih karakteristika graničnih uslova. Ovakav način rada zahteva veliko znanje i iskustvo eksperta, pri čemu ostaje otvoreno pitanje da li dobijeno rešenje ima optimalan skup parametara. Primenom optimizacione metode, koja se zasniva na Gauss-Marquardt-Levenberg-ovom algoritmu, i PEST softvera, ...Dragoljub Bajić, Dušan Polomčić, Jelena Ratković, Predrag Pajić. "Određivanje prostorne distribucije vrednosti hidrauličkih parametara izdani: primer površinskog kopa „Radljevo“" in 9. Međunarodni simpozijum o upravljanju podzemnim resursima, Zaječar 2019., Megatrend Univerzitet, Fakultet za menadžment, Zaječar (2019) М33
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Development of the hybrid MCDM model for evaluating and selecting bucket wheel excavators for the modernization process
This paper presents a methodology for evaluating and ranking different bucket wheel excavators (BWE) for determining which machine should enter in the process of revitalization and modernization. Various multicriteria methods are used. Combining them achieves the best effect when choosing BVE for the modernization process. AHP, TOPSIS, VIKOR, and PROMETHEE methods are used. The hybrid models are developed from the multi-criteria decision making (MCDM) methods and they are used to evaluate the basic indicators that characterize the operation of ...Snezana Savkovic, Predrag Jovancic, Stevan Djenadic, Milos Tanasijevic, Filip Miletic. "Development of the hybrid MCDM model for evaluating and selecting bucket wheel excavators for the modernization process" in Expert Systems with Applications, Elsevier BV (2022). https://doi.org/10.1016/j.eswa.2022.117199 М21а
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Groundwater vulnerability assessment as a tool for understanding karst flow systems and prediction of spring yield - case example of a karst spring in Western Serbia
Modelling approaches in karst hydrogeology imply a high degree of schematization, uncertainty and subjectivity due to the specific nature of karst systems. The need to protect groundwater, especially in karst, has resulted in increasing application of methods for assessing groundwater vulnerability. Vulnerability methods specially developed for karst could assess filtration conditions, anisotropy, specific infiltration, and temporal variability, enabling better characterization and understanding of the karst systems. A recently developed method is the Time Dependent Model (TDM method), where vulnerability ...Vladimir Živanović, Nebojša Atanacković, Slavko Špadijer. "Groundwater vulnerability assessment as a tool for understanding karst flow systems and prediction of spring yield - case example of a karst spring in Western Serbia" in IAH 2024 World Groundwater Congress - Interacting Groundwater, Davos, Švajcarska, 08-13.09.2024, Centre for Hydrogeology and Geothermics (CHYN), UNINE (2024) М34
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Analiza uslova zaštite užičkih vrela primenom TDM metode za ocenu ranjivosti podzemnih voda
Vladimir Živanović, Slavko Špadijer (2024)Definisanje uslova zaštite podzemnih voda u karstnim terenima predstavlja kompleksan i multidisciplinaran zadatak koji zahteva upotrebu savremenih hidrogeoloških metoda. Metode za ocenu ranjivosti podzemnih voda kod kojih se ranjivost definiše na bazi vremena kretanja podzemnih voda mogu značajno da pomognu u delineaciji sanitarnih zona. Primenom ovih metoda se detaljno analiza zaštitna uloga nadizdanske zone tako se preventivne mere mogu usmeriti ka područjima gde su podzemne vode najranjivije i gde najlakše može doći do kontaminacije. Metode za ocenu ranjivosti podzemnih ...uslovi zaštite podzemnih voda, TDM metoda, ranjivost izvorišta podzemnih voda, karstna izdan, užička vrelaVladimir Živanović, Slavko Špadijer. "Analiza uslova zaštite užičkih vrela primenom TDM metode za ocenu ranjivosti podzemnih voda" in XVII Srpski simpozijum o hidrogeologiji sa međunarodnim učešćem , Pirot, Srbija 02-06. oktobar 2024, Beograd : Univerzitet u Beogradu - Rudarsko-geološki fakultet (2024). https://doi.org/10.5281/zenodo.13739864 М33
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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 polynomialsDragan Stankov. "A necessary and sufficient condition for an algebraic integer to be a Salem number" in Journal de theorie des nombres de Bordeaux (2019). https://doi.org/10.5802/jtnb.1076 М23
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Defining location and dip of magnetic anomaly sources applying mathematical transformation
It is significant to define the location and dip of anomaly sources during the geophysical exploration (magnetic, gravity, electric, seismic, etc.). In this paper we presented results obtained during magnetic survey. Applying different method of mathematical transformations on magnetic data we can find the position (edge) and dip of magnetic anomaly sources. For successful solution of this problem, we used combination two method tilt derivative and upward continuation. The study area located in the eastern Serbia, north part of ...Snežana Ignjatović, Milanka Negovanović. "Defining location and dip of magnetic anomaly sources applying mathematical transformation" in 53nd International October Conference on Mining and Metallurgy, IOC 2022, Bor, 3-5. oktobar 2022., Mining and Metallurgy Institute Bor (2022) М33
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Possibility of application of fuzzy logic for stability assessment of underground facilities
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 ...Luka Crnogorac, Rade Tokalić, Đurica Nikšić, Saša Jovanović . "Possibility of application of fuzzy logic for stability assessment of underground facilities" in Mining and environmental protection, Vrdnik, 25 - 28 September 2019, University of Belgrade, Faculty of Mining and geology (2019) М33
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Application of MCDA in the determination of optimal block size for open-pit modelling and mine planning
The process of creating a geological block model as the basis for a further detailed design and planning of mining operations is a very responsible task. Errors made during this initial process are transferred to all other phases of the mining project. Certainly, one of the most important decisions for the modelling process is the choice of the appropriate size of the blocks that form the model itself. The determination of the optimal block size is not a simple ...dimenzije minibloka, višekriterijumska analiza, AHP, modeliranje ležišta, planiranje na površinskim kopovimaPetar Marković, Dejan Stevanović, Milica Pešić Georgiadis, Mirjana Banković. "Application of MCDA in the determination of optimal block size for open-pit modelling and mine planning" in Underground Mining Engineering, Univerzitet u Beogradu, Rudarsko-geološki fakultet (2021) М51
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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: ...Ines Nikolić, Jelena Antić-Stanković, Dragana Božić, Danijela Ranđelović, Bojan Marković, Dominique Jasmin Lunter, Aleksandar Kremenović, Miroslav Savić, Snežana Savić. "Curcumin nanonization using an alternative small-scale production unit: selection of proper stabilizer applying basic physicochemical consideration and biological activity assessment of nanocrystals" in Review on advanced materials science, Walter de Gruyter GmbH (2020). https://doi.org/10.1515/rams-2020-0043 М22
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Моделирање утицаја одступања линије најмањех отпора од пројектоване на интензитет потреса од минирања
Стефан Милановић (2024)Према дефиницији линија најмањег отпора представља најкраће растојање од центра минског пуњења до слободне површине. Oвим истраживањем представљен је утицај линије најмањег отпора, као и њеног одступања од пројектоване на интезитет потреса услед минирања. Проблем линије најмањег отпора је веома заступљен у пракси, где се занемарује изглед слободне површине, који може бити врло неправилан. Линију најмањег отпора је потребно мерити целом дужином минске бушотине према слободној површини, иако је у пракси случај да се мери најчешће као растојање од ...линија најмањег отпора, 3D модел, потреси услед минирања, минирање, слободна површина, метода раздвојених елеменатаСтефан Милановић. Моделирање утицаја одступања линије најмањех отпора од пројектоване на интензитет потреса од минирања, Београд : [С. Милановић], 2024 M70
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Аnaliza mogućnosti povećanja nagiba završne kosine površinskog kopa “Podbraćan”
Vladimir Čebašek, Veljko Rupar (2018)Eksploatacijom boksita iz ležišta "Podbraćan" formiran je površinski kop sa maksimalnom visinom zavšne kosine od 280 m. Redovnom kontrolom stabilnosti trenutnog stanja kosina površinskog kopa utvrđeno je da faktor sigurnosti iznosi Fs = 1.71 – 1.85, a što je ukazalo da postoji mogućnost povećanja nagiba kosine. U radu je prikazan postupak analize mogućnosti povećanja nagiba završne kosine površinskog kopa "Podbraćan".Vladimir Čebašek, Veljko Rupar. "Аnaliza mogućnosti povećanja nagiba završne kosine površinskog kopa “Podbraćan”" in Mining and Geology Today, II international symposium, Belgrade, 04 - 05.12.2018., Rudarski institut, Balkanska akademija nauka, Akademija inženjerskih nauka Srbije (2018). https://doi.org/10.25075/SI.2018.17 М33
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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.Stevan Đenadić, Vesna Damnjanović, Predrag Jovančić, Dragan Ignjatović, Dragutin Jovković, Filip Miletić. "Primena termografije u rudarstvu" in IX Međunarodna konferencija UGALJ 2019, Zlatibor, Srbija, 23-26. oktobar 2019., Jugoslovenski komitet za površinsku eksploataciju (2019) М33
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Fault type assessment based on vertical gravity gradient anomalies – advantages and limitations
The type of dip-slip faults can be assessed based on the analysis of vertical gravity gradients. Theoretically, just a simple comparation of the gradient extreme values can give us an answer whether the fault is normal or reverse (thrust). Practical application of this method is far more complicated and the results depend on a number of parameters, such as a complexity of geological setting, the quality of gravity data, dip angle and displacement of the fault, density contrast, etc. ...Ivana Vasiljević, Snežana Ignjatović, Branislav Sretković. "Fault type assessment based on vertical gravity gradient anomalies – advantages and limitations" in Vth Congress of the Geologists of the Republic of North Macedonia, Ohrid, Republic of North Macedonia, September 27-28, 2024, Macedonian Geological Society (2024) М33
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Properties of fly ash and slag from the power plants
This paper describes the physical, chemical and mineral properties of ash and slag, which were taken from thermal power plants Nikola Tesla A, Nikola Tesla B, Kostolac A and Kostolac B. The knowledge of the mineralogical material composition is important because the type of minerals directly determines the properties of the fly ash and slag and their possible application. Laboratory tests showed that ash and slag samples consist of the following minerals: amorphous materials, quartz, feldspar, mullite, melilite, cristobalite, ...fly ash, slag, physical composition, chemical composition, mineral composition, X-ray diffraction methodMiloš Šešlija, Aleksandra Rosić, Nebojša Radović, Milinko Vasić, Mitar Đogo, Milovan Jotić. "Properties of fly ash and slag from the power plants" in Geologia Croatica, Zagreb : Croatian Geological Survey (2016). https://doi.org/10.4154/gc.2016.26 M23
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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 ...Miroslav Crnogorac, Miloš Tanasijević, Dušan Danilović, Vesna Karović Maričić, Branko Leković. "Selection of Artificial Lift Methods: A Brief Review and New Model Based on Fuzzy Logic" in Energies, MDPI AG (2020) М22
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Coupling of artificial intelligence methods in the development of hybrid intelligent systems
In this paper we present an approach which couples various artificial intelligence (AI) methods in the solution of complex problems that cannot adequately be solved by a single AI method. We argue that the resulting, hybrid intelligent systems (HIS) can be successfully implemented with the use of available AI software libraries. Different coupling methods are analyzed and a classification of hybrid systems based on the chosen method is given. Two case studies of hybrid systems used in mining engineering ...hibridni inteligentni sistemi, spregnuti sistemi, metode veštačke inteligencije, rudarske primene veštačke inteligencijeRanka Stanković, Ivan Obradović, Nikola Lilić. "Coupling of artificial intelligence methods in the development of hybrid intelligent systems" in X Kongres Matematičara, Matematički fakultet, Beograd (2001) М63