Претрага
494 items
-
Conversion of land areas after coal mine closure and reclamation
Otkopavanje uglja površinski i podzemno praćeno je degradacijom zemljišta, promenom formiranja predela i izmenom flore i faune. Od velikog značaja je razvoj novih naučno utemeljenih pristupa obnovljanje antropogeno poremećenih predela zasnovanih na formiranju rekultivacionih i rudarskih tehnologija. Apsolutno je neophodno obezbediti sveobuhvatno kvalitetno očuvanje zemljišnih i vodnih resursa i odrediti rekultivisano zemljište za novu namenu. U ovom članku je dat pregled najpopularnijih metoda rekultivacije zemljišta i mogućnosti rekultivacije zemljišta nakon završetka rekultivacije i zatvaranja rudnika uglja.... Comparison of methods which can be used for choosing a recultivation solution Method Feature Advantage Disadvantage Partial ranking of the User-friendly outranking i ; method, completeness of Does not provide a clear method to actions, based on the : ; : . : : Promethee NH : ranking, partial and ...Radmila Gaćina, Bojan Dimitrijević, Sanja Bajić. "Conversion of land areas after coal mine closure and reclamation" in 9th International conference mining and environmental protection MEP 23 Proceedings, Sokobanja, 24-27.05.2023., Belgrade : University of Belgrade - Faculty of mining and geology (2023)
-
Geotechnical conditions of “Debelo brdo” tunnel construction on the highway E-80: Nis-Merdare-Pristina (“Peace Highway”)
The construction of the highway E-80 has begun in Serbia, which will represent the traffic hub of the Western Balkans and will be part of the main regional transport network of Southeast Europe. Its total length through Serbia is 77 km, and one part of the route is designed through a typical plain terrain, while a larger part of the route passes through hilly terrain. The construction of the tunnel “Debelo brdo” is planned partly in an open cut ...Dragoslav Rakić, Irena Basarić Ikodinović, Radojica Lapčević, Dragan Lukić. "Geotechnical conditions of “Debelo brdo” tunnel construction on the highway E-80: Nis-Merdare-Pristina (“Peace Highway”)" in Proceedings of the XVIII ECSMGE 2024 geotechnical engineering challenges to meet current and emerging needs of society, Lisbon, 26-30 August 2024, CRC Press (2024). https://doi.org/10.1201/9781003431749-356
-
Fuzzy Model for Risk Assessment of Machinery Failures
The main goal of this research was the development of an algorithm for the implementation of negative risk parameters in a synthesis model for a risk level assessment for a specific machine used in the mining industry. Fuzzy sets and fuzzy logic theory, in combination with statistical methods, were applied to analyze the time picture state of the observed machine. Fuzzy logic is presented through fuzzy proposition and a fuzzy composition module. Using these tools, the symmetric position of the ...... defines the membership degree, that is, the membership function of the defined Symmetry 2020, 12, 525 10 of 26 fuzzy sets. The best-fit method (Least Squares Method) is the appropriate procedure to determine the membership function of specific fuzzy sets [33]: di(Ri, Hi) = [(Σ10 j=1(µjR − µjHi))]ˆ ...
... can lead to the same RPN value. [22,31]. The proposed method avoids this. The second advantage of the proposed model is in maximized objectivity (or avoidance of subjectivity) in proposition and composition. Fuzzy models which use AHP method (Analytic Hierarchy Process) in combination with fuzzy logic ...
... analyses may include alternative calculation methods. An FMEA can be performed to identify the potential failure modes for a product or process. The RPN method then requires the analysis team to use past experience and engineering judgment to rate each potential problem according to three rating scales: ...Dejan V. Petrović, Miloš Tanasijević, Saša Stojadinović, Jelena Ivaz, Pavle Stojković. "Fuzzy Model for Risk Assessment of Machinery Failures" in Symmetry, MDPI AG (2020). https://doi.org/10.3390/sym12040525
-
Model upravljanja investicionim projektima otvaranja površinskih kopova uglja
Cvjetko P. Stojanović (2015-04-27)Brze promene u okruženju pred rukovodioce postavljaju mnogobrojne zahteve,pre svega, one koji se tiču ostvarenja ciljeva u zadatom vremenu i raspoloživimsredstvima što zahteva fleksibilan pristup u organizovanju aktivnosti i efikasnost unjihovom sprovođenju.Upravljanje projektima, bilo koje vrste, suštinski, predstavlja veoma složenproces odlučivanja uslovljen velikim brojem ulaznih faktora. Ti faktori treba daomoguće fokusiranje na prioritete i ciljeve, praćenje realizacije, fleksibilnost uprevazilaženju teškoća, prilagođavanje promenama, te kontrolu nad ostvarenimrezultatima. Ovakav način upravljanja zahteva korišćenje proverenih tehnika i alata tetimski rad angažovanih na ...Cvjetko P. Stojanović. "Model upravljanja investicionim projektima otvaranja površinskih kopova uglja" in Универзитет у Београду, Универзитет у Београду, Рударско-геолошки факултет (2015-04-27)
-
Model upravljanja investicionim projektima otvaranja površinskih kopova uglja
Cvjetko P. Stojanović (2015-04-27)Brze promene u okruženju pred rukovodioce postavljaju mnogobrojne zahteve,pre svega, one koji se tiču ostvarenja ciljeva u zadatom vremenu i raspoloživimsredstvima što zahteva fleksibilan pristup u organizovanju aktivnosti i efikasnost unjihovom sprovođenju.Upravljanje projektima, bilo koje vrste, suštinski, predstavlja veoma složenproces odlučivanja uslovljen velikim brojem ulaznih faktora. Ti faktori treba daomoguće fokusiranje na prioritete i ciljeve, praćenje realizacije, fleksibilnost uprevazilaženju teškoća, prilagođavanje promenama, te kontrolu nad ostvarenimrezultatima. Ovakav način upravljanja zahteva korišćenje proverenih tehnika i alata tetimski rad angažovanih na ...Cvjetko P. Stojanović. "Model upravljanja investicionim projektima otvaranja površinskih kopova uglja" in Универзитет у Београду, Универзитет у Београду, Рударско-геолошки факултет (2015-04-27)
-
Razvoj modela upravljanja cirkulacijom u postupku bušenja korišćenjem neuro fazi sistema zaključivanja
Seyed Ali S. Razeghi (2022)Gubitak isplake predstavlja nekontrolisano isticanje bušaćeg fluida kroz formacije kao što su kaverne, pukotine, ili drugi slojevi. Tradicionalne metode procene gubitka isplake se zasnivaju na primeni seizmičkih podataka ili pronalasku „mesta“ gubitka isplake na osnovu raspoloživih podataka iz susednih bušotina. Međutim, ove metode procene nisu pouzdane.‘ U disertaciji je izvršena analiza i procena uticaja parametara bušenja, geoloških faktora, karakteristika formacije i fluida na gubitak isplake kao i na formiranje fraktura u formacijama. Uspostavljeni su modeli koji podrazumevaju proces obrade ...Seyed Ali S. Razeghi. Razvoj modela upravljanja cirkulacijom u postupku bušenja korišćenjem neuro fazi sistema zaključivanja, Beograd : [S. Razeghi], 2022
-
Using Lexical Resources for Irony and Sarcasm Classification
The paper presents a language dependent model for classification of statements into ironic and non-ironic. The model uses various language resources: morphological dictionaries, sentiment lexicon, lexicon of markers and a WordNet based ontology. This approach uses various features: antonymous pairs obtained using the reasoning rules over the Serbian WordNet ontology (R), antonymous pairs in which one member has positive sentiment polarity (PPR), polarity of positive sentiment words (PSP), ordered sequence of sentiment tags (OSA), Part-of-Speech tags of words (POS) ...... the best result (F1 = 80%) was achieved using the RF method over the corpus of #humor tweets, while authors in [6] used Support Vector Machine, Logistic Regression (LR), DT, RF and NB, and the best result (F1 = 74%) was achieved using the LR method with a combination of all sug- gested predictors. Pa ...
... positive polarity, if analysis and detection of the rhetorical figure irony had not been performed. In this paper, we suggest and assess an automatic method of detection of verbal irony using rules of ontological reasoning in the Serbian WordNet (SWN) ontology. In Section 2 we present how irony detection ...
... comparison of Naive Bayes (NB) and Decision Trees (DT) methods used to classify tweets into ironic and non-ironic, showed that the results achieved by DT method measured by the F1 measure were better (71.5% and 53.3% for the balanced and imbalanced set of tweets, respectively). Findings re- ported in [3] depict ...Miljana Mladenović, Cvetana Krstev, Jelena Mitrović, Ranka Stanković. "Using Lexical Resources for Irony and Sarcasm Classification" in Proceedings of the 8th Balkan Conference in Informatics (BCI '17), New York, NY, USA, : ACM (2017). https://doi.org/
-
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
-
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
-
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)
-
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)
-
Sinteza i karakterizacija nanoprahova u CeO2-Bi2O3 sistemu
Marija D. Prekajski (2014-04-04)Nanoprahovi kristalnih faza iz serije čvrstih rastvora u pseudo-binarnom sistemuCeO2-Bi2O3 sintetisani su primenom jednostavne i ekonomične samopropagirajućemetode na sobnoj temperaturi korišćenjem nitrata metala i natrijum-hidroksida kaopolaznih supstanci. Osim krajnjih članova niza, CeO2 i niskotemperaturne polimorfnemodifikacije α-Bi2O3, sintetisani su i čvrsti rastvori nominalnog sastava Ce1-xBixO2-δ,gde je x = 0,1; 0,2; 0,3; 0,4; 0,5; 0,6; 0,7; 0,8; 0,9. Rezultati proučavanja metodomrendgenske difraktometrije na polikristalnom materijalu i ramanske spektroskopskeanalize pokazali su da su sintetisani prahovi sa nižim sadržajem bizmuta (x = 0,1 ...nanostrukturni materijali, čvrsti rastvori, CeO2, Bi2O3, rendgenskadifraktometrija praha, Ritveldova metoda, mikrostrukrurna analizaMarija D. Prekajski. "Sinteza i karakterizacija nanoprahova u CeO2-Bi2O3 sistemu" in Универзитет у Београду, Универзитет у Београду, Рударско-геолошки факултет (2014-04-04)
-
Kristalne strukture Cs2HoSi4O10F i Cs2TmSi4O10F
... previously unknown chemical composition - Cs2HoSi4O10F and Cs2TmSi4O10F were obtained in form of single crystals. The compounds were synthesized by the method of crystal growth from a high-temperature solution (Tmax = 1373 K) using REE2O3 (REE = Ho, Tm), SiO2 and CsF as starting materials. The crystal ...Predrag Dabić, Sabina Kovač, Aleksandar Kremenović. "Kristalne strukture Cs2HoSi4O10F i Cs2TmSi4O10F" in XXVII konferencija Srpskog kristalografskog društva, Kragujevac, 16-17. septembar 2021., Beograd : Srpsko kristalografsko društvo (2021)
-
Postojeće stanje i budući trendovi u preventivnoj zaštiti podzemnih voda Srbije
Vladimir Živanović (2022)Podzemne vode predstavljaju osnovni, a u mnogim zemljama i jedini resurs za javno vodosnabdevanje stanovništva tako da zaštita podzemnih voda predstavlja bitan preduslov za njihovo dugotrajno i održivo korišćenje. Kako u svetu, tako i u Srbiji, zaštita podzemnih voda se najvećim delom svodi na primenu preventivnih mera zaštite. Kod planiranja zaštite većih prostora sve više se koriste metode za ocenu ranjivosti podzemnih voda. Njihova primena je posebno naglašena u karstnim područjima zato što se tu izdvajaju delovi terena sa ...Zaštita podzemnih voda, karte ranjivosti podzemnih voda, karta hazarda, karte rizika od kontaminacije, monitoring podzemnih voda, SrbijaVladimir Živanović. "Postojeće stanje i budući trendovi u preventivnoj zaštiti podzemnih voda Srbije" in Zbornik radova XVI srpskog Simpozijum o hidrogeologiji sa međunarodnim učešćem, Univerzitet u Beograd, Rudarsko-geološki fakultet (2022)
-
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
-
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
-
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
-
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
-
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
-
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