Претрага
486 items
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Cutting Resistance Laboratory Testing Methodology for Underwater Coal Mining
... laboratory testing methods are used to determine the cutting resistance of rock samples, the uniaxial compression test method and the wedge test method. 5.1. Uniaxial Compression Test Method The uniaxial compressive strength, σc [23], has no direct relationship to the cutting resistance required by excavation ...
... test method. This means that the modified methodology provides tests that can be used to report the compressive strength test and the wedge test for different values of confining pressure. The stated testing method is also known as the triaxial test, while the modification of the primary method was performed ...
... developed a wedge test method [1,14,17] to determine cutting resistance for hard and compact soils by measuring the penetration resistance of the bucket knife or tooth in the laboratory on the drilling core samples or block-shaped rock material samples. Consequently, the testing method is most used for d ...Vladimir Čebašek, Veljko Rupar, Stevan Đenadić, Filip Miletić. "Cutting Resistance Laboratory Testing Methodology for Underwater Coal Mining" in Minerals, MDPI AG (2021). https://doi.org/10.3390/min11060564
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The number of nonunimodular roots of a reciprocal polynomial
Dragan Stankov (2023)We introduce a sequence Pd of monic reciprocal polynomials with integer coefficients having the central coefficients fixed as well as the peripheral coefficients. We prove that the ratio of the number of nonunimodular roots of Pd to its degree d has a limit L when d tends to infinity. We show that if the coefficients of a polynomial can be arbitrarily large in modulus then L can be arbitrarily close to 0. It seems reasonable to believe that if ...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. "The number of nonunimodular roots of a reciprocal polynomial" in Comptes rendus mathematique, Elsevier France Editions Scientifiques et Medicales (2023). https://doi.org/10.5802/crmath.422
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Developing Students’ Mining and Geology Vocabulary Through Flashcards and L1 in the CLIL Classroom
... combined method of flashcards and L1 in the CLIL is useful learning method (Q1) (37.63%), which facilitates learning vocabulary (Q2) (38.78%), moreover, many of the students agree that the method maximized the lexical improvement (Q3) (47.31%), closely relating the lexical content and method with the ...
... quality of their exposure to English inside and outside the school. We hypothesized that CLIL method will lead to better learning results compared with traditional foreign language learning method due to bigger and better opportunity to enlarge both receptive and productive vocabularies. On the ...
... 38%) labeled the method as discouraging. The findings suggest that L1, flashcards and CLIL pedagogy, as a classroom technique tailored to help students’ develop specific vocabulary, is highly effective, well balanced, and creating new language habits. This type of method slowly introduces elevated ...Lidija Beko, Ivan Obradović, Ranka Stanković. "Developing Students’ Mining and Geology Vocabulary Through Flashcards and L1 in the CLIL Classroom" in Proceedings of the Second International Conference on Teaching English for Specific Purposes and New Language Learning Technologies, May, 22-24, 2015, Niš, Serbia, Faculty of Electronic Engineering, University of Niš, Niš : Faculty of Electronic Engineering (2015)
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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)
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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)
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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)
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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)
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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)
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Mine surveying works for the purpose of excavating the remaining reserves of bauxite in the deposit of “Podbracan”
... works for the purpose of excavating the remaining reserves of bauxite in the deposit of "Podbracan" 4.1. Mining method The applied mining method, named the sublevel caving excavation method in crosswise direction, was chosen based on the relevant mining- geological parameters, mining condi- tions and ...
... - standard deviation of tra- verse point in the direction of x-axis; i E σ - standard deviation of tra- verse point in the direction of y-axis; 1i N σ − - standard deviation of the previous traverse point in the direction of x-axis; 1i E σ − - standard deviation of the previous traverse ...
... and Herzegovina (The Republic of Srpska). The ore reserves of the bauxite deposit of "Podbracan" were excavated till 2010 by using the open pit method of mining at the central and northern part of the deposit up to the +410m. Above this level, in the southern part, 1,120,000t of ore reserves ...Aleksandar Milutinović, Aleksandar Ganić, Thamer Rayes Diyab, Rade Tokalić, Meri Ganić. "Mine surveying works for the purpose of excavating the remaining reserves of bauxite in the deposit of “Podbracan”" in Revista Escola de Minas, School of Mines Magazine, Sao paulo, Brasil : SciELO (2015)
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Komparacija metoda XRF i ICP-MS na uzorcima uglja i produkata sagorevanja
Ugljevi niskog ranga – ligniti u Republici Srbiji predstavljaju glavnu energetsku sirovinu koja se koristi za proizvodnju električne energije. Rudarstvo u Srbiji doprinosi bruto dodatoj vrednosti sa 1,8% (2020; https://publikacije.stat.gov.rs/). Sagorevanjem ugljeva niskog ranga u termoelektranama generišu se velike količine elektrofilterskog pepela i pepela, koje često predstavljaju jedan od izvora zagađenja životne sredine usled sadržaja toksičnih elemenata. Dalja upotreba produkata sagorevanja zavisi od njihovog sastava i sadržaja toksičnih mikroelemenata. Svakodnevno sagorevanje lignita u termoelektranama uslovljava konstantan monitoring potencijalno toksičnih ...Branko Kostić, Dejan Prelević, Sabina Kovač, Ksenija Eraković, Dragana Životić. "Komparacija metoda XRF i ICP-MS na uzorcima uglja i produkata sagorevanja" in 18. Kongres geologa Srbije "Geologija rešava probleme", Divčibare, 01-04 jun 2022., Srpsko geološko društvo (2022)
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Classifying large strains from digital imagery: application to analogue models of lithosphere deformation
... interpretation of this deformation, we have developed a novel method thatcan qualitatively describe shape changes coming from extensional, shortening and horizontalshearing (strike-slip) deformation or combinations of these. This method is based on a logarithmicmeasure of stretch and results agree well ...
... our models. Thus, we provide tools with which the evolution of 2D tectonic deformationcan be interpreted in a physically meaningful manner, but our method may be useful outside therealm of tectonics. Our software to compute deformation is freely available and can be used topost-process incremental di ...Taco Broerse, Nemanja Krstekanić, Cor Kasbergen, Ernst Willingshofer. "Classifying large strains from digital imagery: application to analogue models of lithosphere deformation" in EGU General Assembly 2021, Vienna, Austria, 19.-30.4.2021., EGU (2021)
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Ground surface subsidence monitoring using sentinel-1 in the “Kostolac” open pit coal mine
Zoran Gojković, Milan Kilibarda, Ljiljana Brajović, Miloš Marjanović, Aleksandar Milutinović, Aleksandar Ganić (2023)Open pit coal mining affects surrounding populated areas, resulting in terrain surface deformation. Surface deformation should be monitored as often as possible to control deformations and prevent potential incidents. This paper analyzes time series deformation estimated from the Sentinel-1 satellite images using the Persistent Scatterer Interferometry method to monitor subsidence rates caused by open pit mining activities. It is possible to measure deformations using classical geodetic methods, but those are rarely used in practice because they are time-consuming and ...Zoran Gojković, Milan Kilibarda, Ljiljana Brajović, Miloš Marjanović, Aleksandar Milutinović, Aleksandar Ganić. "Ground surface subsidence monitoring using sentinel-1 in the “Kostolac” open pit coal mine" in Remote Sensing (2023). https://doi.org/10.3390/rs15102519
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Prirodna ranjivost karstnih izdani srednjetrijaskih krečnjaka u oblasti između reka Bistrice, Uvca i Lima
Branislav Petrović, Veljko Marinović, Zoran Stevanović. "Prirodna ranjivost karstnih izdani srednjetrijaskih krečnjaka u oblasti između reka Bistrice, Uvca i Lima" in 18. Kongres geologa Srbije, Srpsko geološko društvo (2022)
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Multicriteria Analysis and Optimization of Groundwater Control Systems with Variable Values of Criterion over Predefined Time Points
Milica Stepanović, Dragoljub Bajić, Dušan Polomčić. "Multicriteria Analysis and Optimization of Groundwater Control Systems with Variable Values of Criterion over Predefined Time Points" in Comptes rendus de l'Académie Bulgare des Sciences, "Prof. Marin Drinov" Publishing House of Bulgarian Academy of Sciences (2021). https://doi.org/10.7546/CRABS.2021.08.09
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Evaluation And Perspectives Of Underground Coal Mines In Serbia
... using the Analytic Hierarchy Process method, as described in following chapter. AHP evaluation of underground coal mines in Serbia The Analytic Hierarchy Process (AHP) is a multi-criteria decision-making approach introduced by Saaty [4]. The AHP method enables users to determine the weights ...
... to whether output and productivity could be increased and whether there are enough resources to justify the necessary investment. Based on AHP method and scores allocated for each factor, the mines were ranked according to technical potential. Key words: Underground mining, Potential, Restructuring ...
... weights of the parameters in the solution of a multi-criteria problem. In the AHP method, a hierarchical model consisting of objectives, criteria, sub-criteria and alternatives is used for every problem [5]. Solving a problem using AHP is carried out using the weights or priorities of the criteria ...Vladimir Milisavljević, Milena Lekić, Ivica Ristović, Vojin Čokorilo, Aleksandar Cvjetić. "Evaluation And Perspectives Of Underground Coal Mines In Serbia" in 7th Balkan Mining Congress Preceedings - BalkanMine2017, Prijedor, 11-13. oktobar 2017., Banjaluka : University of Banjalika, Faculty of Mining, RS, BiH (2017)
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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)
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Correlation Between Dynamic CBR and Compaction and Bearing Capacity of Pavement Foundation Layers
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... determined, and the physical-me- chanical parameters are defined based on laboratory testing for incorporation into the substrate layer; – the method of using a non-standardized dynamic California Bearing Ratio (CBR,) device and the defi- nitions of its values under laboratory and field conditions ...
... layers were established. The results of CBR, are extremely underrepresented in the literature, probably owing to the low preva- lence of this method worldwide. The first CBR, study considered mineral materials for roads [1] and report- ed good correlation between static and dynamic test results ...
... reported [4]. Owing to its short duration and ease, CBR, testing using a LWD can become widespread as an alterna- tive to the classic quality control method in the process of compaction or estimation of the substrate bear- ing capacity [5]. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov ...Milan Bogdanović, Snežana Bogdanović, Dragoslav Rakić, Irena Basarić Ikodinović. "Correlation Between Dynamic CBR and Compaction and Bearing Capacity of Pavement Foundation Layers" in Soil Mechanics and Foundation Engineering, Springer Science and Business Media LLC (2024). https://doi.org/10.1007/s11204-024-09939-x
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Improving Document Retrieval in Large Domain Specific Textual Databases Using Lexical Resources
Large collections of textual documents represent an example of big data that requires the solution of three basic problems: the representation of documents, the representation of information needs and the matching of the two representations. This paper outlines the introduction of document indexing as a possible solution to document representation. Documents within a large textual database developed for geological projects in the Republic of Serbia for many years were indexed using methods developed within digital humanities: bag-of-words and named ...... initial method. Figure 11 depicts the MAP for all 55 queries over the six ranking methods for indexed documents and the initial method. The worst performing ranking method lnu ltu has an almost three times better performance than the initial method, whereas the results for the best performing method InQuery ...
... the results of the tfc tfc method were omitted as they were identical to the results of the tfc nfc method. The precision of the initial system is in general better among first-ranked documents than in the case of the improved system, with the excep- tion of the InQuery method, while the recall is better ...
... ascending order of the difference between the best per- forming ranking method for indexed documents InQuery and the performance of the initial method, and the results are depicted in Fig. 7. Fig. 7. Differences between initial method and InQuery indexing sorted in ascending order. We shall now discuss ...Ranka Stanković, Cvetana Krstev, Ivan Obradović, Olivera Kitanović. "Improving Document Retrieval in Large Domain Specific Textual Databases Using Lexical Resources" in Trans. Computational Collective Intelligence - Lecture Notes in Computer Science 26, Springer (2017). https://doi.org/10.1007/978-3-319-59268-8_8
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Development of integrated fuzzy model for mine management optimization
Miodrag Čelebić, Sanja Bajić, Dragoljub Bajić, Dejan Stevanović, Duško Torbica, Vladimir Malbašić (2023)... applying the FAHP method described in |*|. The optimization procedure and decision making; are presented in seven steps [12]. Step 1. Mathematical optimization begins with predefined criteria that affect the selection of one of several alternatives. Then a matrix of criterion X is con- C. R. Acad ...
... 2,...,m;k X i. Step 4. Weight priority vectors are defined as W!= (c' (4i),C(A>),...,“ (An)T) where A4;(i= 1,2,...,n). 1416 M. Čelebić, S. Bajić, D. Bajić et al. Step 5. The final weights are calculated applying; a matrix algebra approach, namely the additive normalization method [11]. 'The ...
... n sciences, 8, 199—249. Š| CHANG D. Y. (1996) Applications of the extent analysis method on fuzzy AHP, Rur. J. Oper. Res., 95, 649 655. “} ZnU K., Y. JING, D. CHANG (1999) A discussion on extent analysis method and applications of fuzzy AHP, Eur. J. Oper. Res., 116, 450 456. TOLGA FE., M. DEMIRCAN ...Miodrag Čelebić, Sanja Bajić, Dragoljub Bajić, Dejan Stevanović, Duško Torbica, Vladimir Malbašić. "Development of integrated fuzzy model for mine management optimization" in Comptes rendus de l'Académie Bulgare des Sciences (2023)
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Characterization of Natural Clay from Bogovina (Serbia) and Possible Utilization in Sorption of the Herbicides
... adsorption method was used to measure the efficiency of inorganic and organic modified montmorillonites for the sorption of the S-metolachlor. Mineralogical characterization of natural clay samples was performed using the X-ray diffraction method. This method was also used ...
... used in order to track structural changes in montmorillonites during the modification treatment and adsorption process. Based on the X-ray diffraction diagrams, it was concluded that, after saturation with the HDTMA complex, there was an expansion of the interlayer space. Depending on the ...Lazar Kaluđerović, Zorica Tomić, Rada Đurović-Pejčev, Maja Milošević. "Characterization of Natural Clay from Bogovina (Serbia) and Possible Utilization in Sorption of the Herbicides" in Eurosoil2020, online event 2021, Eurosoil, Frontiers Abstract Book (2021)