Претрага
462 items
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Valorization of non-balanced coal reserves in Serbia for underground coal gasification
David Petrović, Lazar Kričak, Milanka Negovanović, Stefan Milanović, Jovan Marković, Nikola Simić, Ljubisav Stamenić (2019)In the name of a better and safer energy future, it is our responsibility to focus our knowledge and activities to save on imported liquid and gas fossil fuels, as well as coal on which energy security of Serbia is based. The rationalization in the use of available energy resources certainly positively affects economy and the environment of a country. This paper indicates motivations for the application of the underground coal gasification process, as well as surface gasification for ...... than 20-25%, while in UCG it is about 72-96%, taking into account the useful volume of coal. In addition, it should be kept in mind that the UCG method mainly utilizes non-balanced deposits and excavated residues of balanced reserves. * Corresponding author, e-mail: stamenic(a)msn.com Petrović ...
... indicates how significant economic effects of the UCG application are. In parallel, environmental benefits are also exceptional. Utilization of UCG method does not generate any slag and ash, there is no degradation of the terrain comparing to the un- derground exploitation of coal, and also no special ...
... next third, fourth, etc., fig. 4, [7]. the traditional mothod In order for the gasification process to be performed more efficiently by the CRIP method, the mentioned half round layer in the injection borehole help to avoid possible problematic geo- logical structures of the coal bed, as well ...David Petrović, Lazar Kričak, Milanka Negovanović, Stefan Milanović, Jovan Marković, Nikola Simić, Ljubisav Stamenić. "Valorization of non-balanced coal reserves in Serbia for underground coal gasification" in Thermal Science (2019). https://doi.org/10.2298/TSCI190725390P
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The Fuzzy–AHP Synthesis Model for Energy Security Assessment of the Serbian Natural Gas Sector
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 ...... number of ranking methods in the literature. The analytic hierarchy process (AHP) method was used in this study. AHP is a mathematical method in multi-criteria decision-making (MCDM) that is most often used [60]. This method is characterized by the possibility to emphasize the influence of a partial indicator ...
... consistency index CR: CR = CI/RI (10) where: RI—empirical consistency index of the multi-criteria AHP method (for n = 3, RI = 0.58 [62]). The aforementioned ranking procedure using the AHP method was repeated for each partial indicator within each synthesis indicator. (IV) The fourth step in the formation ...
... methods and for the purposes of developing this synthetic model; ranking based on the application of the multi criteria AHP (analytic hierarchy process) method was used. In this way, the ranking data are used as input data to the fuzzy set, which is further analyzed in the fuzzy composition process. Fuzzy ...Aleksandar R. Madžarević, Dejan D. Ivezić, Miloš L. Tanasijević, Marija A. Živković. "The Fuzzy–AHP Synthesis Model for Energy Security Assessment of the Serbian Natural Gas Sector" in Symmetry, MDPI AG (2020). https://doi.org/10.3390/sym12060908
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Improvement of geodatabase queries within GeolISS
Ranka Stanković (2008)... which are represented in a GIS by digital data. There are two general approaches used for storing data in a GIS: the raster and the vector method. The first method represents geological features as images, whereas the latter uses geometrical shapes, namely different types of geometrical objects, for ...
... related attributes. Modern GIS technologies are based on digital information, with various methods used for creating digital data. The most common method of data creation is digitization, where a hard copy map or research plan is transferred to digital form by means of a computer-aided design program ...Ranka Stanković. "Improvement of geodatabase queries within GeolISS" in Review of the National Center for Digitization, Beograd : Faculty of Mathematics, Belgrade (2008)
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Application of Expansive Mortars for the Formation of Artificial Screens During Blasting in Urban Areas
During construction of buildings in urban areas, sometimes there is a need to blast solid rock mass in the immediate vicinity of the surrounding buildings. In that case, the aim is not only to increase the efficiency of blasting, but also to reduce harmful effects of ground vibration induced by blasting. At the same time, it is very important to protect the buildings located in the safe zone from the blast site as well as remaining rock mass around ...Milanka Negovanović, Lazar Kričak, Stefan Milanović, Nikola Simić, Jelena Majstorović. "Application of Expansive Mortars for the Formation of Artificial Screens During Blasting in Urban Areas" in 31st International Conference Ecological Truth & Environmental Research-EcoTER'24, Sokobanja, 18-21. jun 2024, Bor : Tehnički fakultet u Boru (2024)
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Речници у дигиталном добу - информатичка подршка за српски језик
Биљана Рујевић (2022)Морфолошки речници српског језика представљају електронски језички ресурс који има значајну историју развоја и коришћења за потребе обраде природних језика. С обзиром на то да су чувани у облику датотека чији је број нарастао па је самим тим управљање речницима постало отежано јавила се потреба за смештањем информација из речника у облик лексикографске базе. Како би се омогућио симултани рад на развоју речника за више корисника јавила се потреба за веб-апликацијом заснованој на лексикографској бази. Како би се размотриле ...Биљана Рујевић. Речници у дигиталном добу - информатичка подршка за српски језик, Београд : [Б. Рујевић], 2022
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Refinement of waste phosphogypsum from Prahovo, Serbia: characterization and assessment of application in civil engineering
Josip Išek, Lazar Kaluđerović, Nikola Vuković, Maja Milošević, Ivana Vukašinović, Zorica Tomić (2020)... of the samples' containers, and the purified gypsum sample was measured once, after the con- tainer was sealed. By applying the y-spectrometry method, the activity concen- tration of _ŠU was determined from its decay products Th (63keV) and/or "Pa (1000 keV). The ecay products of ? Ra, _ Bi (609 ...
... similar result was obtained with calcium sulfate whiskers synthesized from flue gas desulfurization of gypsum using the atmospheric acidification method (Sun ef al., 2016). Whiteness index The WI of 52.5%, determined for raw phosphogypsum (PG1), is too low for potential use in some industries ...
... Yao X. (2016) Developing high performance phosphogypsum- based cementitious materials for oil-well cementing through a step-by-step optimization method. Cement and Concrete Composites, 72, 299-308. IAEA (2013) Radiation Protection and Management of NORM Residues in the Phosphate Industry. Safety ...Josip Išek, Lazar Kaluđerović, Nikola Vuković, Maja Milošević, Ivana Vukašinović, Zorica Tomić. "Refinement of waste phosphogypsum from Prahovo, Serbia: characterization and assessment of application in civil engineering" in Clay Minerals, Cambridge University press (2020). https://doi.org/10.1180/clm.2020.11
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Some models for determination of parameters of the soil oscillation law during blasting operations
... specific work environment and by particular blasting conditions. 2.2.1. 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 representing a common model [5,6]. 2.2.2. Model 2—Determining the Parameters by Applying ...
... determination of parameters K and n in the Sadovskii equation. To determine the parameters in the Sadovskii formula, in addition to the usual least square method, two more new models were applied. In the models the parameters K and n were determined by applying the quotient of the relative growth of oscillation ...
... friction, φ = 52˝; ‚ porosity, p = 3.5%; ‚ velocity of longitudinal waves, cp = 2400.00 m/s; ‚ velocity of transverse waves, cs = 1400.00 m/s. 4.1.2. Method of Blasting in the Veliki Krivelj Open Pit The measurements of shocks resulting from blasting in the Veliki Krivelj Open Pit were performed during ...Suzana Lutovac, Dragan Medenica, Branko Gluščević, Rade Tokalić, Čedomir Beljić. "Some models for determination of parameters of the soil oscillation law during blasting operations" in Energies, Basel, Switzerland : MDPI (2018). https://doi.org/10.3390/en9080617
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Models of Determining the Parameters of Rock Mass Oscillation Equation with Experimental and Mass Blastings
... models, using the values obtained by experimental measurements. 3.3.1. 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 [9,10]. 3.3.2. Model 2—Determining the Parameters through ...
... characteristics of the rock mass, and it is determined based on trial blasting for a specific work environment. Thus, this paper offers analysis of the method for determination of parameters of the rock mass oscillation equation, which are conditioned by rock mass properties and blasting conditions. Practical ...
... cohesion, C = 7.5 MPa • strength coefficient, f = 11 • volume density, γ = 26 kN/m3 • angle of internal friction, ϕ = 50◦ • porosity, p = 3.6% 4.1.2. Method of Blasting in Majdanpek Open Pit The measurements of shocks resulting from blasting in Majdanpek open pit were performed during blasting using h ...Suzana Lutovac, Branko Gluščević, Rade Tokalić, Jelena Majstorović, Čedomir Beljić. "Models of Determining the Parameters of Rock Mass Oscillation Equation with Experimental and Mass Blastings" in Minerals, Basel : MDPI AG, Basel, Switzerland (2018). https://doi.org/10.3390/min8020070
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The Reciprocal Algebraic Integers Having Small House
Dragan Stankov (2021)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 Reciprocal Algebraic Integers Having Small House" in Experimental Mathematics (2021). https://doi.org/ 10.1080/10586458.2021.1982425
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Review: Methodological approaches and research techniques for addressing construction and remediation problems in karst reservoirs
Saša Milanović, Ljiljana Vasić (2021)Saša Milanović, Ljiljana Vasić. "Review: Methodological approaches and research techniques for addressing construction and remediation problems in karst reservoirs" in Hydrogeology Journal, Springer Science and Business Media LLC (2021). https://doi.org/10.1007/s10040-020-02280-1
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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
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FTIR spectroscopic study оf S-мetolachlor сorption оn inorganic and organically modified montmorillonite from Bogovina
... was collected from the Bogovina locality (Serbia). Clay fraction, with montmorillonite as the dominant mineral, was separated using the decantation method. Clay fraction (< 2 mm) was then treated with 30% hydrogen peroxide in order to remove organic matter from the sample. 330 SERBIAN SOCIETY OF ...
... and marked as NaM-SM, 1H-SM, 2H-SM, 3H-SM, 4H-SM, IP-SM, 2P-SM, 3P-SM, and 4P- SM. FTIR spectroscopy All samples were investigated using FTIR method (Fourier-transform infrared spectroscopy). All results were obtained in Laboratory for infrared spectroscopy at the Faculty of Science, University ...
... Figure 3. Suggested interactions betveen PTMA*cations and phenolin interlayerspace of montmorillonite (Majdan et al., 2009) CONCLUSION FTIR method was very useful in the process of examination of interactions between Na- montmorillonite and organic complexes such as HDTMA bromide and PTMA chloride ...Lazar Kaluđerović, Zorica Tomić, Jelena Bogosavljević, Ljubomir Životić, Maja Milošević. "FTIR spectroscopic study оf S-мetolachlor сorption оn inorganic and organically modified montmorillonite from Bogovina" in Book of Proceedings / 3rd International and 15th National Congress Soils for Future Under Global Challenges, 21-24 September 2021 Sokobanja, Serbia , Belgrade : Serbian Society of Soil Science (2021)
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Long-term rockslope monitoring and rockfall prediction
Miloš Marjanović, Biljana Abolmasov, Marko Pejić, Jelka Krušić. "Long-term rockslope monitoring and rockfall prediction" in Proceedings of 3rd European Regional Conference of IAEG/ Athens/ Greece/ 6-10 October 2021, International Association for Engineering Geology and the Environment (2021)
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Geotehnički efekti razaranja komunalnog otpada različitim postupcima zbijanja
Jovana M. Janković Pantić (2022)Odlaganje otpada na komunalne deponije predstavlja osnovni način zbrinjavanja otpada u Srbiji. Kako bi se prostor za deponovanje materijala racionalno koristio potrebno ga je svakodnevno zbijati sa unapred definisanom količinom vode koja se dodaje. Dobro zbijeni komunalni otpad zauzima manju zapreminu i omogućuje sigurnije skladištenje, pa je korisno prethodno laboratorijski odrediti parametre zbijanja: maksimalnu suvu zapreminsku težinu (dmax) i optimalnu vlažnost (wopt). U Srbiji do sada nisu određivani parametri zbijanja, dok je u svetu primenjivana standardna metoda (Proktorov opit) ...Jovana M. Janković Pantić. Geotehnički efekti razaranja komunalnog otpada različitim postupcima zbijanja, Beograd : [J. Janković Pantić], 2022
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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, PyrophylliteBorislav Vasić, Radoš Gajić, Ivana Milošević, Žarko Medić, Marina Blagojev, Marko Opačić, Aleksandar Kremenović, Dejan Lazić. "Natural two-dimensional pyrophyllite: Nanoscale lubricant, electrical insulator and easily-machinable material" in Applied Surface Science, Elsevier BV (2022). https://doi.org/10.1016/j.apsusc.2022.155114
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Hydrochemical features and their controlling factors in the Kucaj-Beljanica Massif, Serbia
Earth-Surface Processes, Geology, Pollution, Soil Science, Water Science and Technology, Environmental Chemistry, Global and Planetary ChangeFen Huang, Ljiljana Vasic, Xia Wu, Jianhua Cao, Saša Milanovic. "Hydrochemical features and their controlling factors in the Kucaj-Beljanica Massif, Serbia" in Environmental Earth Sciences, Springer Science and Business Media LLC (2019). https://doi.org/10.1007/s12665-019-8452-4
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Mesozoic carbonate rocks in Serbia used as dimension stone
Vesna Matović, Tijana Vojnović Ćalić (2016)The building industry in Serbia uses, to a great extent, imported natural stone for architectural purposes. The significance of local deposits, particularly limestones, is not adequately perceived despite the country’s abundance of these valuable resources. Therefore, this study focuses on Serbia’s Mesozoic carbonate rocks, specifically on the deposits of four selected quarries: Klisura, Skrzut, Struganik, and Tisnica. The quality and prospects of the application of these limestones has not yet been the subject of a detailed, comprehensive investigation. Therefore, ...... density was determined according to the standard method SRPS B.B8.032 (1980) (corresponding to Euro- pean Committee for Standardization EN 1936:2006). On the same, but powdery samples, the real densities were determined using a pycnometer method. Considering the values of real and bulk density ...
... ion, according to Folk (1959) and Flugel (2004). The CaO and MgO contents were determined for the same samples, applying: a complexo- metric method using a standardized solution of 1 MEDTA (ethylenediaminetetraacetic acid) as the titrant. To determine the quality of the selected carbonate rocks ...
... density, the total porosity was calculated. The water absorption was determined according to the standard method SRPS B.B8.010 (1981) (corre- sponding to European Committee for Standardization EN 13755:2009). The resistance to frost was determined by @ Springer subjecting the sample to 25 cycles ...Vesna Matović, Tijana Vojnović Ćalić. "Mesozoic carbonate rocks in Serbia used as dimension stone" in Bulletin of Engineering Geology and the Environment, Springer Science and Business Media LLC (2016). https://doi.org/10.1007/s10064-015-0722-0
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Crystallography and Surface Oxidation of Stoichiometric Arsenopyrite from Šumadija-Kopaonik Pb-Zn/Polymetallic Ore District (Serbia)
Ivana Jelić, Aleksandar Pačevski, Aleksandar Kremenović, Aleš Šoster, Andreja Šestan, Janez Zavašnik (2023)The behaviour and stability of arsenopyrite largely depend on its crystal structure, but studies of crystallography and structural defects are scarce. For clarification, we investigated a series of natural arsenopyrite crystals from the polymetallic Pb-Zn-(±Cu,Ag,Au,Sb,Bi,W) Šumadija-Kopaonik ore district (Serbia) by powder X-ray diffraction (XRPD). Among them, samples from the Drenjak gold mineralisation showed near-stoichiometric FeAsS composition and were further investigated by conventional and high-resolution transmission electron microscopy methods. TEM revealed abundant planar crystallographic defects and epitaxial surface oxide layer ...Inorganic Chemistry, Condensed Matter Physics,General Materials Science, General Chemical Engineering, crystal structure, FeAsS, oxidation, TEM, XRPD... crystallography [8] and has continued until present day [9]. Several different structural arrangements have been sug;gested, influenced by the method and accuracy applied in the investigation and by its similarity to marcasite (orthorhombic FeS>, Pnnm) and rutile (tetragonal TiO>», P4, /mnm) ...
... and an incident angle of 8*. We chose he conventional Ar-ion etching for the TEM sample preparation over the site-specific ocused ion beam (FIB) method to avoid possible Ga implantation during, the sample preparation procedure. The electron-transparent samples were mounted in a low-background dual ...
... analysed inside the TEM chamber by energy-dispersive X-ray spectroscopy (EDS). The quantification was assessed by the Cliff-Lorimer ratio thin section method (four iterations), with the Si-K line as the ratio standard element and line [20]. The calculated composition, mean of 16 spot analyses, was determined ...Ivana Jelić, Aleksandar Pačevski, Aleksandar Kremenović, Aleš Šoster, Andreja Šestan, Janez Zavašnik. "Crystallography and Surface Oxidation of Stoichiometric Arsenopyrite from Šumadija-Kopaonik Pb-Zn/Polymetallic Ore District (Serbia)" in Crystals, MDPI AG (2023). https://doi.org/10.3390/cryst13020278
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Investigation of quantitative indicators of anisotropy based on longitudinal elastic waves propagation velocities with uncertainty
... mailto:suzana.lutovac@rgf.bg.ac.rs 2 Gligorić M., Majstorović J., Lutovac S. several times per second because of its shortness, so this method is called impulse method. Elastic waves in rock or sample are representing deformation propagation, so depending of type of deformations, waves of different ...
... Kahraman, 2007; Kılıc, 2006; Myrin and Malaga, 2006; Sousa et al., 2005; Valdelon et al., 1996; Vasanelli et al., 2015; Yavuz et al., 2006). Measuring method of ultrasonic waves velocity propagation is based on the modelling of the wave propagation process. The process of induction and wave emission is ...Miloš Gligorić, Jelena Majstorović, Suzana Lutovac. "Investigation of quantitative indicators of anisotropy based on longitudinal elastic waves propagation velocities with uncertainty" in Underground Mining Engineering, Belgrade : University of Belgrade - Faculty of Mining and Geology (2018). https://doi.org/10.5937/PodRad1832001G
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Non-Detonating Chemical Mixture for Non-Invasive Methods of Rock Breaking
Within the Innovation developed several different non-detonating chemical mixtures for non-invasive methods of rock breaking. Laboratory and polygon tests gave the satisfactory results and knowledge enough to start the practical experiments in the field. The basis of this innovation is a theoretical assumption that certain chemical mixtures release a large quantity of gases during combustion. If these gases are found in the enclosed space a growing pressure on the walls of the chamber in which combustion takes place will ...Lazar Kričak, Milanka Negovanović, Nikola Simić, Stefan Milanović. "Non-Detonating Chemical Mixture for Non-Invasive Methods of Rock Breaking" in X International Scientific Congress Innovations 2024, Varna, Bulgaria, 24-27. jun 2024, Scientific Technical Union of Mechanical Engineering "Industry 4.0" (2024)