Претрага
637 items
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Mitigating hydrate formation in onshore gas wells: A case study on optimization techniques and prevention
Gas wells, particularly those situated onshore, play a vital role in the global energy sector by supplying a significant portion of natural gas. However, operational challenges, notably gas hydrate formation, pose substantial issues, leading to complications such as flowline blockages and unexpected well shutdowns. Gas hydrates, crystalline structures resembling ice, ...Gas Well, Gas Hydrate Formation, Well Modeling, Well Performance Optimization, Choke Position Adjustments, Methanol InjectionMilica Ješić, Bojan Martinović, Stefan Stančić, Miroslav Crnogorac, Dušan Danilović. "Mitigating hydrate formation in onshore gas wells: A case study on optimization techniques and prevention" in Underground Mining Engineering, Beograd : Rudarsko-geološki fakultet (2023)
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Utilizing sewage wastewater heat in district heating systems in Serbia: effects on sustainability
Marija Živković, Dejan Ivezić (2021)Transformation of the heating sector is recognized as being essential for ensuring reliable and afordable energy services provided with reduced consumption of energy sources and diminished impact on the environment and less import dependency. The possibility of utilizing energy sources that otherwise would be wasted needs to be considered and treated as a big advantage of district heating systems. Despite many advantages, sewage wastewater heat is still a mostly unused resource at the global level and a totally unused ...рекуперација топлоте из отпадних вода, систем даљинског грејања, топлотне пумпе, енергетске уштеде, емисија угљендиоксида, енергетска безбедност, Србија... gives an indicator of possible heat energy that can be produced in the system with the heat pump in wastewa- ter treatment plant. Based on presented data from the city of Šabac, it was determined, using Eq. (11), by utilizing wastewater heat, which can be produced = q HP 379.8 kWh of heat energy ...
... whose wider utiliza- tion can be provided by centralized supply systems. This paper presents a methodology for evaluation of the positive effects related to the goals of sustainable devel- opment: energy savings, climate change mitigation, and energy security, which can be obtained through utilization ...
... energy sources. Although outcomes of this research do not include economical parameters, they can serve as a support in assessing investments in different technical options. The obtained results can be useful for investors, city gov- ernments and policy makers by providing them bound- ary data for ...Marija Živković, Dejan Ivezić. "Utilizing sewage wastewater heat in district heating systems in Serbia: effects on sustainability" in Clean Technologies and Environmental Policy, Springer Science and Business Media LLC (2021). https://doi.org/10.1007/s10098-021-02063-6
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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
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Adsorption and degradation of some psychiatric drugs by sol-gel synthesized titania-based photocatalysts: influence of tungsten and sodium content
Nina L. Finčur, Maja J. Šćepanović, Mirjana Grujić-Brojčin, Biljana F. Abramović, Jugoslav B. Krstić, Aleksandar Kremenović, Tatjana Srećković, Aleksandar Golubović (2019)Mesoporous anatase nanopowders were doped with 0.05−0.5 mol% of W6, in order to obtain more efficient photocatalyst than TiO2 Degussa P25 in the degradation of amitriptyline (AMI) under simulated solar irradiation (SSI). Dominant XRPD peaks were ascribed to anatase phase, with additional peaks which could correspond to brookite, TiO2 bronze and sodium titanate, Na2Ti9O19. The Raman scattering measurements have confirmed anatase as dominant phase, with broad Raman feature at ~270 cm−1 possibly related to Ti–O–Na stretching vibration. All W-doped ...Sol-gel synthesis, Doped titania nanopowders, XRPD, Raman spectroscopy, Adsorption and photocatalytic degradation, Psychiatric drugsNina L. Finčur, Maja J. Šćepanović, Mirjana Grujić-Brojčin, Biljana F. Abramović, Jugoslav B. Krstić, Aleksandar Kremenović, Tatjana Srećković, Aleksandar Golubović. "Adsorption and degradation of some psychiatric drugs by sol-gel synthesized titania-based photocatalysts: influence of tungsten and sodium content" in Journal of Sol-Gel Science and Technology, Springer Science and Business Media LLC (2019). https://doi.org/10.1007/s10971-019-04925-4
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Fuzzy optimization in hydrodynamic analysis of groundwater control systems: Case study of the pumping station “Bezdan 1”, Serbia
Dragoljub Bajić, Dušan Polomčić (2014)A groundwater control system was designed to lower the water table and allow the pumping sta-tion “Bezdan 1” to be built. Based on a hydrodynamic analysis that suggested three alternative solutions, mul-ticriteria optimization was applied to select the best alternative. The fuzzy analytic hierarchy process methodwas used, based on triangular fuzzy numbers. An assessment of the various factors that influenced the selec-tion of the best alternative, as well as fuzzy optimization calculations, yielded the “weights” of the alternativesand the ...groundwater lowering, groundwater management scenario, fuzzy analytic hierarchy process,expert knowledge, triangular fuzzy numbers, linguistic variables... long-term average maximum levels, some of the wells can be shut down, as needed. Conclusion Human beings are often uncertain in assigning eva- luation scores by conventional methods, so decision making frequently involves uncertainties. FAHP can cope with that difficulty. The method has the ability ...
... water table. In some cases, the FAHP analysis can eliminate certain criteria, assigning them weights close to zero. Such clustering may help managers make decisions based on the most important criteria, especially in cases where more precise information can be expen- sive to obtain. Proposed for future ...
... as well as the employees' publications. - The Repository is available at: www.dr.rgf.bg.ac.rs Introduction The best way engineers or scientists can express their opinions is in fact everyday verbal communica- tion. It is a significant source of uncertainty, because of the transfer of both information ...Dragoljub Bajić, Dušan Polomčić. "Fuzzy optimization in hydrodynamic analysis of groundwater control systems: Case study of the pumping station “Bezdan 1”, Serbia" in Geološki anali Balkanskoga poluostrva, Belgrade : University of Belgrade - Faculty of mining and geology (2014). https://doi.org/10.2298/GABP1475103B
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Quantitative landslide risk assessment in the city of Tuzla
In the climate-changing conditions, geological environment interacts more dramatically with the urban fabric than before. The urbanization is expansive and more aggressive than before, but so are the weather extremes and long-term climate trends. In effect, many processes which can be triggered by either side, nature or engineering, are becoming more pervasive than before, and such is the case with landslides. Dealing and managing landslides requires few crucial steps, starting from collecting data on landslide location and typology – ...... urbanization is expansive and more aggressive than before, but so are the weather extremes and long- term climate trends. In effect, many processes which can be triggered by either side, nature or engineering, are becoming more pervasive than before, and such is the case with landslides. Dealing and managing ...
... zones of their increased temporal probability for a given return period, and finally, estimating which elements at risk these exceeded probabilities can affect and at what level. In this work, a practical case is represented to illustrate all these steps and demonstrate successful implementation of ...
... INTRODUCTION Urban sprawl tends to consume larger and larger portions of natural environment. In response, the interaction between urban and natural can be violent from both sides. For instance, the fragile balance of the natural slopes is undermined by slope cuts and de-vegetation for infrastructure ...Miloš Marjanović, Biljana Abolmasov, Cvjetko Sandić, Miralem Mulać, Petar Begović. "Quantitative landslide risk assessment in the city of Tuzla" in SCG-Xiii International Symposium on Landslides. Cartagena, Colombia- February 22-26, 2021, International Society for Soil Mechanics and Geotechnical Engineering (2021)
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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)
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Medical Domain Document Classification via Extraction of Taxonomy Concepts from MeSH Ontology
Mihailo Škorić, Mauro Dragoni (2019)This paper is a result of a task that was presented to attendants of Keyword Search in Big Linked Data summer school, that was organized by Vienna University of Technology, under the Keystone COST action in the summer of 2017. It presents a specific approach to the classification via creation of minimal document surrogates based on the US National medical library’s MeSH ontology, which is derived from the Medical Subject Headings thesaurus. In a series of previously classified medically ...... according to the med- ical subjects from the MeSH ontology, version for 2016.2 Ontology can be queried via web,3 where you can get predefined queries, the ones for classes and predicates being aong them, or where other data can be obtained with the new SPARQL queries. The documentation, RDF triplets and the ...
... application of 56,309 term replacements over 10,000 documents, giving a total of 563,090,000 transformations. Further research can go towards using 9 In hindsight, a similar approach can also generate a different type of substitution based on loops or regular expressions, which would speed up replacements ...
... the case example download are available online,4 and there is also an option for previewing the predicate via access point, where the predicates can be seen in tabular form, as well as their descriptions and XML labels, which is especially important if a local copy of the MeSH ontology is used5 Ontology ...Mihailo Škorić, Mauro Dragoni. "Medical Domain Document Classification via Extraction of Taxonomy Concepts from MeSH Ontology" in Infotheca, Faculty of Philology, University of Belgrade (2019). https://doi.org/10.18485/infotheca.2019.19.1.3
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An intelligent hybrid system for surface coal mine safety analysis
Nikola Lilić, Ivan Obradović, Aleksandar Cvjetić. "An intelligent hybrid system for surface coal mine safety analysis" in Engineering Applications of Artificial Intelligence (2010)
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Substitution reactions of some novel sterically hindered monofunctional Pd(II) complexes
Reakcije supstitucije monofunkcionalnih kompleksa [(TLtBu)PdCl]+ i [Pd(tpdm)Cl]+, gde je TLtBu = 2,6-bis[(1,3-di-terc-butilimidazolin-2-imino)metil]piridin i tpdm = terpiridindimetan, sa nukleofilima kao što su: tiourea, I−, Br−, NO2−, piridin i dimetil-sulfoksid (DMSO) proučavani su u 0,1 M vodenom rastvoru NaClO4 u prisustvu 10 mM NaCl. Reakcije su sprovedene na tri različite temperature (288, 298 i 308 K) korišćenjem tehnike zaustavljenog protoka na različitim temperaturama. Reakcije supstitucije su praćene pod uslovima pseudo prvog reda sa velikim viškom nukleofila. Dobijeni rezultati pokazuju da kompleks ...... n. Better reactiv- ity of I� ion compared to that of Br� and NO2 � ions can be explained by different polarizability of these nucleophiles. Namely, iodide ion is the most polarized halide ion (4.7 � 10�24 cm3) [31], so it can be classified as ‘‘the softest’’ halide ion. ‘‘Soft’’ (polarizable) nucleophile ...
... explanation. Better reactiv- ity of I” ion compared to that of Br~ and NO27 ions can be explained by different polarizability of these nucleophiles. Namely, iodide ion is the most polarized halide ion (4.7 x 10-74 cm?) [31], so it can be classified as “the softest” halide ion. “Soft” (polarizable) nucleophile ...
... substitution reactions of square-planar complexes [1–6,21,22]. It is well known that relatively small struc- tural modifications in a multidentate ligand can produce significant changes in the reactivity of the complexes [7–9]. There is a high interest among scientists nowadays in the field of the steric ...Aleksandar Mijatović, Jovana Bogojeski, Biljana Petrović, Živadin D. Bugarčić. "Substitution reactions of some novel sterically hindered monofunctional Pd(II) complexes" in Inorganica Chimica Acta, Elsevier BV (2011). https://doi.org/10.1016/j.ica.2011.11.031
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Flood protection and water utilization of karst poljes: example of Gatačko Polje, Eastern Herzegovina
Tina Dašić, Ljiljana Vasić (2020)Earth-Surface Processes,Geology, Pollution, Soil Science, Water Science and Technology, Environmental Chemistry,Global and Planetary ChangeTina Dašić, Ljiljana Vasić. "Flood protection and water utilization of karst poljes: example of Gatačko Polje, Eastern Herzegovina" in Environmental Earth Sciences, Springer Science and Business Media LLC (2020). https://doi.org/10.1007/s12665-020-08987-4
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Stratigraphy and microfossils (radiolarians and planktonic foraminifers) of the Upper Cretaceous (upper Santonian–lower Campanian) Struganik limestone (Western Serbia)
Liubov G. Bragina, Nikita Yu. Bragin, Ludmila F. Kopayevich, Nevenka Đerić, Nataša Gerzina Spajić (2019)Liubov G. Bragina, Nikita Yu. Bragin, Ludmila F. Kopayevich, Nevenka Đerić, Nataša Gerzina Spajić. "Stratigraphy and microfossils (radiolarians and planktonic foraminifers) of the Upper Cretaceous (upper Santonian–lower Campanian) Struganik limestone (Western Serbia)" in Palaeoworld, Elsevier BV (2019). https://doi.org/10.1016/j.palwor.2019.05.001
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Definisanje parametara čvrstoće na smicanje kod izvođenja kosina u ispucalom stenskom masivu
Zoran M. Berisavljević (2016-04-01)Definisanje parametara čvrstoće na smicanje ispucalih stenskih masa predstavlja jedanod najzahtevnijih zadataka mehanike stena. Geotehnička istraživanja su uglavnomograničena na rezultate laboratorijskih ispitivanja malih makroskopski homogenihuzoraka, sa kojih se vrši ekstrapolacija rezultata na terensku razmeru. Ispitivanja semogu vršiti in situ, ali su i ona ograničena veličinom korišćene aparature imikrolokacijom na kojoj se vrše ispitivanja. Pored toga, moguće je vršiti različitaispitivanja na fizičkim modelima, koja su veoma složena i skupa. Ekstrapolacijapodataka sa malog uzorka na terensku razmeru daje mnogo bolje rezultate ...naponsko stanje, ispucalost, heterogenost, čvrstoća na smicanje, geološki indeksčvrstoće, Hoek-Brownov materijal, kompozitni uzorci, dezintegracija, povratna analizaZoran M. Berisavljević. "Definisanje parametara čvrstoće na smicanje kod izvođenja kosina u ispucalom stenskom masivu" in Универзитет у Београду, Универзитет у Београду, Рударско-геолошки факултет (2016-04-01)
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A comparative study of the molecular and isotopic composition of biomarkers in immature oil shale (Aleksinac deposit, Serbia) and its liquid pyrolysis products (open and closed systems)
Gordana Gajica, Aleksandra Šajnović, Ksenija Stojanović, Jan Schwarzbauer, Aleksandar Kostić, Branimir Jovančićević (2021)The molecular and isotopic composition of biomarkers in initial bitumen isolated from immature (0.41% Rr) oil shale samples (Aleksinac deposit) and liquid products obtained by pyrolysis in open (OS) and closed (CS) systems are studied. The influence of pyrolysis type and variations of kerogen type on biomarkers composition and their isotopic signatures in liquid products is determined. The applicability of pyrolysis type, numerous biomarkers and carbon isotopic compositions (δ13C) of n-alkanes in liquid pyrolysates is established. Pyrolysis experiments were ...Uljni šejl, Aleksinac, organska supstanca, otvoreni i zatvoreni sistem pirolize, biomarkeri, izotopski sastav ugljjenikaGordana Gajica, Aleksandra Šajnović, Ksenija Stojanović, Jan Schwarzbauer, Aleksandar Kostić, Branimir Jovančićević. "A comparative study of the molecular and isotopic composition of biomarkers in immature oil shale (Aleksinac deposit, Serbia) and its liquid pyrolysis products (open and closed systems)" in Marine and Petroleum Geology, Elsevier BV (2021). https://doi.org/10.1016/j.marpetgeo.2021.105383
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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 ...... complex problems can be solved if instead of rigor and greater accuracy of descriptions of certain phenomena, the exact opposite is done, making those descriptions imprecise [42]. In classical (bivalent) logic, each statement can only be true or false, that is, the value of a statement can be only 0 if the ...
... complex linguistic expressions can be obtained. Linguistic variables can be assigned one or more linguistic values that are related to numerical values through membership and class functions [48]. Symmetry 2020, 12, 908 5 of 42 For example, if the variable “STRENGTH” can have the values weak, strong ...
... as possible. It can be concluded that the obtained criterion dependencies can be used in defining the energy security of any energy system and the performed methodology of the fuzzy–AHP Symmetry 2020, 12, 908 39 of 42 synthesis model for analysis of energy development scenarios can adapt its general ...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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GIS Application Improvement with Multilingual Lexical and Terminological Resources
... queries is the most frequently used one. Templates for queries are defined in the geodatabase, but the user can update and insert new search definitions. Selection of words chosen for the query can be substantially improved by using lexical resources, morphological dictionaries and transducers in ...
... which enable automatic production of all inflectional forms. The Serbian morphological dictionary of simple words contains 122,000 lemmas, which can generate approximately 1,400,000 different lexical words. The Serbian morphological dictionary of compounds contains about 4,300 lemmas (generating ...
... system 2 . These transducers play an important role in the query expansion application WS4QE, by enabling a more elaborate query expansion that can significantly improve retrieval performances. The use of transducers is especially important in the case of compounds. For instance, if a query ...Ranka Stanković, Ivan Obradović, Olivera Kitanović. "GIS Application Improvement with Multilingual Lexical and Terminological Resources" in Proceedings of the 5th International Conference on Language Resources and Evaluation, LREC 2010, Valetta, Malta, May 2010, Valetta, Malta : European Language Resources Association (2010)
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Split-Desktop software for the analysis of fragment size distribution of blasted rock mass
Milanka Negovanović, Lazar Kričak, Stefan Milanović, Jovan Marković, Nikola Simić, Snežana Ignjatović (2023)Drobljenje stena je najvažniji pokazatelj u proceni efekata miniranja pri proizvodnom miniranju u površinskoj eksploataciji. Stepen drobljenja stena ima veliki uticaj na efikasnost daljih operacija utovara, transporta, drobljenja i mlevenja. Optimalno drobljenje stena pri proizvodnom miniranju utiče na smanjenje ukupnih troškova proizvodnje. Stoga je pouzdana procena veličine drobljenja odminirane stenske mase veoma važno pitanje, ne samo u operacijama miniranja, već i u rudarskoj proizvodnji. Za predviđanje distribucije veličine komada odminirane stenske mase postoje različiti empirijski modeli. KUZ-RAM model omogućava ...Milanka Negovanović, Lazar Kričak, Stefan Milanović, Jovan Marković, Nikola Simić, Snežana Ignjatović. "Split-Desktop software for the analysis of fragment size distribution of blasted rock mass" in 9th International Conference Mining and environmental protection, Sokobanja, Serbia, 24 – 27. May 2023, Belgrade : University of Belgrade, Faculty of Mining and Geology (2023)
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Optimisation of underground mine decline development system using genetic algorithm
... environment we treat development of an underground mine as access infrastructure composed of different decline sections. Access infrastructure designing can be treated as spanning the spatial network which will connect all main terminals (points). In our model we defined spatial network by adequate nonlinear ...
... ore bodies it is necessary to interconnect them into one integrated system. There are different development systems (shaft, decline, adit) which can be used to create such system. Suppose the deposit characteristics indicate that decline development system is preferred one. In such environment ...
... t we treat development of an underground mine as access infrastructure composed of different decline sections. Access infrastructure design can be treated as spanning the spatial network which will connect all main terminals (points). Main terminals are: mineral processing facility, surface breakout ...Zoran Gligorić, Aleksandar Ganić, Rade Tokalić, Aleksandar Milutinović. "Optimisation of underground mine decline development system using genetic algorithm" in Underground mining engineering, Beograd : Univerzitet u Beogradu – Rudarsko–geološki fakultet (2014)
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Defining structural correlation using of total horizontal gradient
Gravity data can help to define the structural correlation along significant vertical shifts. The different procedures of mathematical transformations on gravity data are applied to define structural correlations. The paper presents the results obtained using the procedure total horizontal gradient on gravity data. The application of the total horizontal gradient helped to detect contacts with a large dip angle (vertical or subvertical contacts), which can be interpreted as faults. The study area located in the wider area of the ...Snežana Ignjatović, Ivana Vasiljević, Milanka Negovanović. "Defining structural correlation using of total horizontal gradient" in The 52nd International October Conference on Mining and Metallurgy, Bor, novembar 29-30.11.2021., University of Belgrade ‐ Technical faculty in Bor, Bor, November 2021 (2021)
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Analysis and Calculation of MMRS and Primary Gas Distribution Network in Urban Environment – Case Study Kučevo
Aleksandar Madžarević, Pavle Janković (2022)Oblast primene prirodnog gasa je veoma široka. Kao energent može se koristiti za proizvodnju energije u elektranama, toplanama i postrojenjima za kombinovanu proizvodnju energije ili za zadovoljavanje različitih toplotnih potreba u industriji i širokoj potrošnji. Gas se može upotrebiti i kao sirovina u hemijskoj i petrohemijskoj industriji, a tokom poslednjih decenija nalazi primenu i u saobraćaju kao pogonsko gorivo u SUS motorima. Sa ekološkog stanovišta, prirodni gas predstavlja najprihvatljiviji izvor energije u poređenju sa drugim fosilnim gorivima. Pri sagorevanju ...Aleksandar Madžarević, Pavle Janković. "Analysis and Calculation of MMRS and Primary Gas Distribution Network in Urban Environment – Case Study Kučevo" in Međunarodni Kongres o procesnoj industriji - PROCESING '22, Beograd : SMEITS, Društvo za procesnu tehniku (2022)