Претрага
111 items
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Evaluation of the effects of wastewater heat pump integration into district heating systems by simulation
Dejan Ivezić, Marija Živković, Dimitrije Manić, Aleksandar Madžarević, Boban Pavlović, Dušan Danilović (2023)The integration of wastewater heat pumps (using purified water) in district heating systems is analyzed in this paper. The simulation procedure is proposed to analyze the impacts of stochasticity of purified water temperature and flow to heat pump integration and operation. The analysis includes calculation of the daily and seasonal coefficient of performance, as well as fossil fuel savings and CO2 emission reduction due to wastewater heat pump use. The proposed procedure is implemented for the case study in ...Dejan Ivezić, Marija Živković, Dimitrije Manić, Aleksandar Madžarević, Boban Pavlović, Dušan Danilović. "Evaluation of the effects of wastewater heat pump integration into district heating systems by simulation" in Thermal Science, National Library of Serbia (2023). https://doi.org/10.2298/TSCI220813168I
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Energetska efikasnost elektromotora na površinskim kopovima
Snežana Aleksandrović, Ilija Jeftenić (2023)Snežana Aleksandrović, Ilija Jeftenić. "Energetska efikasnost elektromotora na površinskim kopovima" in 11. Međunarodna konferencija “Ugalj i kritični materijali" CCM 2023, Zlatibor, 11-14. oktobar 2023. , Beograd : Jugoslovenski komitet za površinsku eksploataciju (2023)
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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 ...... energy use and energy efficiency measures. Natural gas appliances are more efficient, characterized by compact structure, lower costs of exploitation and low investment costs. Usage of natural gas also impacts on the environment also through the fact that there are no needs to build storage. Expert ...
... per year with investment costs of 85.5 million € [58]; 2. Gas interconnection project with Croatia—main gas pipeline MG-08 Gospodjince (Futog, Serbia)—Sotin (border with Croatia) with 95 km length (in Serbia) and a planned capacity of 1.5 BCM per year with investment costs of 60 million € [58]; 3. ...
... and a planned capacity of 1.6 BCM per year with investment costs of 85 million € (6 million € part of investment in Serbia) [58]; 4. Expending Underground storage “Banatski Dvor” capacities from 800 mcm to 1 BCM per year with investment costs of 65 million € [58]. Based on this list of infrastructure ...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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Determining the Availability of Continuous Systems at Open Pits Applying Fuzzy Logic
This work presents a model for determining the availability of continuous systems at open pits by applying fuzzy logic and fuzzy inference systems. The applied model was formed by the synthesis of independent partial indicators of availability. The model is based on an expert system for assessing the availability of continuous mining systems. The availability of the system, as a complex state parameter, is decomposed into the partial indicators, reliability, and convenience of maintenance, and the fuzzy compositions, used ...системи, континуални систем експоатације, површински коп, рударство, расположивост, фази логика, max–min композиција, min–max композицијаMiljan Gomilanović, Miloš Tanasijević, Saša Stepanović. "Determining the Availability of Continuous Systems at Open Pits Applying Fuzzy Logic" in Energies, MDPI AG (2022). https://doi.org/10.3390/en15186786
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A Model for Determining Fuzzy Evaluations of Partial Indicators of Availability for High-Capacity Continuous Systems at Coal Open Pits Using a Neuro-Fuzzy Inference System
This paper presents a model for determining fuzzy evaluations of partial indicators of the availability of continuous systems at coal open pits using a neuro-fuzzy inference system. The system itself is a combination of fuzzy logic and artificial neural networks. The system availability is divided into partial indicators. By combining the fuzzy logic and artificial neural networks, a model is obtained that has the ability to learn and uses expert judgment for that learning. This paper deals with the ...системи, континуални системи експлоатације (роторни багер-транспортер-дробилично постројење), рударство, расположивост, меко рачунарство, фази логика, ANN, ANFISMiljan Gomilanović, Miloš Tanasijević, Saša Stepanović, Filip Miletić. "A Model for Determining Fuzzy Evaluations of Partial Indicators of Availability for High-Capacity Continuous Systems at Coal Open Pits Using a Neuro-Fuzzy Inference System" in Energies, MDPI AG (2023). https://doi.org/10.3390/en16072958
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Advantages and challenges in presenting mathematical content using EDX platform
... materials through peer review processes and use of modern technology. 2) Innovation in the teaching process, openness and availability with low costs. 3) Short periods for publishing learning material, while serving the needs of particular student populations mailto:ivan.obradovic@rgf.bg.ac ...Marija Radojičić, Ivan Obradović, Ranka Stanković, Olivera Kitanović, Roberto Linzalone. "Advantages and challenges in presenting mathematical content using EDX platform" in The Seventh International Conference on e-Learning (eLearning-2016), Belgrade : Metropolitan University (2016)
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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 ...... condition of a machine which are time-based (time between failures, time to repair, pollution level, injuries, setback costs, spare parts and replacement costs, delivery to customer delay costs etc.) they have to be acquired in the field. In addition, if data are not classified, or are of low quality, those ...
... have an impact on the operation of a system, while the term “very high” describes failures that cause enormous damage to a system, affecting repair costs and causing production delay. Appropriate classes (from one to 10) were allocated to the fuzzy sets, where classes nine and 10 describe failures that ...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
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Gate Road Support Deformation Forecasting Based on Multivariate Singular Spectrum Analysis and Fuzzy Time Series
Luka Crnogorac, Rade Tokalić, Zoran Gligorić, Aleksandar Milutinović, Suzana Lutovac, Aleksandar Ganić (2021)Underground mining engineers and planners in our country are faced with extremely difficult working conditions and a continuous shortage of money. Production disruptions are frequent and can sometimes last more than a week. During this time, gate road support is additionally exposed to rock stress and the result is its progressive deformation and the loss of functionality of gate roads. In such an environment, it is necessary to develop a low-cost methodology to maintain a gate road support system. ...deformacije podgrade, lasersko skeniranje, višekanalna singularna spektralna analiza, prognoza, klasterisanje fuzzy vremenskih serija... reconstruction, and type of support that can be used to decrease the progressive deformation. An effective deformation forecast can result in a decrease of costs and delays. There are many different approaches to obtaining future states of support deformation. Ding-Ping Xu et al. [1] compared the predictions ...
... reconstruction, and type of support that can be used to decrease the progressive deformation. An effective deformation forecast can result in a decrease of costs and delays. There are many different approaches to obtaining future states of support deformation. Ding-Ping Xu et al. [1] compared the predictions ...
... activities based on crisp values. The developed model enables mine planners to create an effective plan to support repairs, including duration time and costs of reparation with respect to forecasted deforma- tions. Future research will be focused on carrying an in situ measuring of the deformations in an ...Luka Crnogorac, Rade Tokalić, Zoran Gligorić, Aleksandar Milutinović, Suzana Lutovac, Aleksandar Ganić. "Gate Road Support Deformation Forecasting Based on Multivariate Singular Spectrum Analysis and Fuzzy Time Series" in Energies, MDPI (2021). https://doi.org/https://doi.org/10.3390/en14123710
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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 ...... useful energy source, some of the advantages are: — the absence of heavy mining in underground, as well as in surface mining conditions, — minimum costs of transporting gas to consumers, — significantly lower cost of the final product (normalized to 1 MJ of energy), — there is no significant degradation ...
... sometimes caused by the exploitation of groundwater. At hat time it is necessary to define what the priority is. The UCG should not be foreseen at all costs. Due to the lowering ofthe level of groundwater, there is an increase in the soil's own mass in the reduction zone, which leads to subsequent subsidence ...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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Razvoj ARCGIS geobaze površinskog kopa korišćenjem UML CASE alata
... prospective open pits, model the geology and the terrain, estimate the reserves, plan the yearly production, monitor statistical data on exploitation costs, monitor the position and availability of mining equipment (excavators, conveyor belts, trucks, etc.), the state of mining objects, works on mine benches ...Aleksandra Tomašević, Ljiljana Kolonja, Ivan Obradović, Ranka Stanković, Olivera Kitanović. "Razvoj ARCGIS geobaze površinskog kopa korišćenjem UML CASE alata" in Podzemni radovi, Beograd : Univerzitet u Beogradu - Rudarsko-geološki fakultet (2012)
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Дефинисање археолошких објеката на локалитету Кремените њиве применом Ојлерове 3Д деконволуције на магнетометријске податке
... greatest advantage of Archaeological Geophysics is that it is non‐destructive, and with the increase in speed and measurement resolution, the costs of the investigation and excavation have decreased consi‐ derably. The use of magnetic measurements in archaeological prospecting allows to obtain ...Весна Цветков, Илија Васиљевић, Бранислав Сретеновић, Весна Дамњановић. "Дефинисање археолошких објеката на локалитету Кремените њиве применом Ојлерове 3Д деконволуције на магнетометријске податке" in Књига апстраката 17. Конгрес геолога Србије, Врњачка Бања 17-20. мај, Српско геолошко друштво (2018)
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Izbor rotornih bagera za proces revitalizacije: primer rotornih bagera SRs 1200 u rudarskom basenu Kolubara
Predrag Jovančić, Dragan Ignjatović, Stevan Đenadić, Filip Miletić, Goran Todorović, Dragan Novaković (2020)Revitalizacija je proces ili skup tehničkih zahvata na mašini kojim se vrši zamena svih dotrajalih ili oštećenih delova metalne konstrukcije. Sastavni deo procesa revitalizacije je i modernizacija zastarele elektro-mašinske opreme. Principi revitalizacije sasvim sigurno nisu sadržani u okviru redovnog godišnjeg ili dnevnog održavanja. Oni predstavljaju održavanje onih veličina koje su značajne za mašinu kao celinu (u ovom slučaju rotorni bager). U ovom radu su analizirani rotorni bageri oznake SRs 1200. Na površinskim kopovima rudarskog basena Kolubara takvih bagera ima ...Predrag Jovančić, Dragan Ignjatović, Stevan Đenadić, Filip Miletić, Goran Todorović, Dragan Novaković. "Izbor rotornih bagera za proces revitalizacije: primer rotornih bagera SRs 1200 u rudarskom basenu Kolubara" in XIV Međunarodna konferencija OMC 2020, Zlatibor, Srbija, 14-17. oktobar 2020., Jugoslovenski komitet za površinsku eksploataciju (2020)
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FTIR spectroscopic study оf S-мetolachlor сorption оn inorganic and organically modified montmorillonite from Bogovina
... to the migration into groundwater (Cohen et al., 1986). The reduced inhibitory activity requires repetition of treatment, which leads to increased costs and a negative impact on the environment. Therefore, attempts were made to create a formulation that would lead to an improvement in the inhibitory ...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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Regional Slope Stability Analysis in Landslide Hazard Assessment Context, North Macedonia Example
Miloš Marjanović, Biljana Abolmasov, Igor Peshevski, James Reeves, Irena Georgievska. "Regional Slope Stability Analysis in Landslide Hazard Assessment Context, North Macedonia Example" in Understanding and Reducing Landslide Disaster Risk, Springer International Publishing (2020). https://doi.org/10.1007/978-3-030-60227-7_29
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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... eness and flexibility assessed. In the present study, as the number of wells increased, so did capital expendi- ture and operating and maintenance costs. However, it should be noted that in some cases the construction of wells is more economical than the pumping time. Flexibility included the ability ...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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Towards Better Valorisation of Industrial Minerals andRocks in Serbia—Case Study of Industrial Clays
... of small thickness, mostly medium or poor quality of raw materials, and underground method of exploitation (Table 3). In addition, high transport costs prevent potential exports, and domestic utilisation is impossible without bentonite processing plants and related industry that would use the final ...
... is additionally complicated by the underdeveloped market due to recession in Serbian and surrounding economies and industries, and high transport costs in case of possible export of IMR. Figure 1. Interrelation between the origin of a mineral deposit and economic geology. 4.1. Permitting in Serbia ...Vladimir Simić, Dragana Životić, Zoran Miladinović. "Towards Better Valorisation of Industrial Minerals andRocks in Serbia—Case Study of Industrial Clays" in Resources, MDPI AG (2021). https://doi.org/10.3390/resources10060063
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Model za optimizaciju graničnog saržaja metala u rudi u funkciji dugoročnog planiranja površinskih kopova
Daniel P. Kržanović (2016-06-14)Optimizacija graničnog sadržaja metala u rudi jedan je od osnovnih koraka u planiranju i dizajniranju površinskih kopova i ima za cilj postizanje maksimalne neto sadašnje vrednosti (NPV). Iz tog razloga, optimizacija graničnog sadržaja i danas je predmet mnogih istraživanja u rudarskoj nauci, sa ciljem rešavanja praktičnih problema u eksploataciji ležišta.Dugoročno planiranje eksploatacije na površinskim kopovima podrazumeva sagledavanje svih relevantih parametara i faktora (geologije rudnog ležišta, tehnologije proizvodnog procesa, kapaciteta otkopavanja i prerade, troškova, cena metala, iskorišćenja i dr) kako ...površinski kop, dugoročno planiranje, optimizacija graničnog sadržaja, maksimizacija neto sadašnje vrednosti (NPV).... capacity of mining and processing, costs, metal prices, recovery, etc.) for maximum profit of mining project. By applying various methods and optimization algorithms, which are used today in the modern software tools, it is possible to manage the production costs and revenues or economy of operation ...
... optimizaciji graničnog sadržaja u monometaličnim ležištima uvođenjem dve vrste pseudo troškovaa: troškova odlaganja (engl. Delay costs) i troškova promene (engl. Change costs). Whittle je kasnije razvio metodu za optimizaciju graničnog sadržaja, koja predstavlja modifikovanu metodu Lane, i koja je i ...
... Cash costs) koji su proporcionalni količini otkopane i prerađene rude. Primer: troškovi goriva, ulja i maziva, guma i dr. 2 ) Troškovi gotovine koji su proporcionalni vremenu. Primer: troškovi održavanja. 3 ) Pseudo troškovi koje nazivamo troškovi odlaganja (kašnjenja) (engl. Delay costs). 4 ...Daniel P. Kržanović. "Model za optimizaciju graničnog saržaja metala u rudi u funkciji dugoročnog planiranja površinskih kopova" in Универзитет у Београду, Универзитет у Београду, Рударско-геолошки факултет (2016-06-14)
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The state and perspective of the natural gas sector in Serbia
The strategy of long-term energy development of Serbia identifies an increase of share of natural gas in final energy consumption as one of the main aims. Serbia has signed a strategic agreement with the Russian Federation on cooperation in the oil and gas sector, within which the project South Stream pipeline is planned to be realized. In addition, the Republic of Serbia has signed the Treaty that establishes the Energy Community and accepted the obligation to implement the Energy ...Dejan Ivezić, Marija Živković, Dušan Danilović, Aleksandar Madžarević, Miloš Tanasijević. "The state and perspective of the natural gas sector in Serbia" in Energy Sources, Part B: Economics, Planning and Policy, Taylor & Francis Group, LLC (2016). https://doi.org/http://dx.doi.org/10.1080/15567249.2013.858796
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Prognoza operativne efikasnosti aktivnog podzemnog rudnika zasnovana na teoriji sivih sistema
Svetlana M. Štrbac-Savić (2016-06-10)Efikasnost predstavlja preduslov za opstanak svake rudarske kompanije, posebno u uslovima izuzetno konkurentnog trţišnog okruţenja kao što je to rudarska industrija. Efikasnost oznaĉava sposobnost kompanije da ispuni svoje kratkoroĉne ili dugoroĉne ciljeve. Operativna efikasnost se definiše kao odnos izmeĊu ulaznih parametara potrebnih za odvijanje proizvodnje i pokazatelja dobijenih proizvodnjom. U kontekstu rudarskog poslovanja, operativna efikasnost se odnosi na vreme potrebno da se mineralno dobro transformiše u novĉana sredstva. Visoka operativna efikasnost se postiţe kada se ostvari prava kombinacija karakteristika ...podzemni rudnik, operativna efikasnost, prognoza, teorija sivih sistema, stohastiĉke diferencijalne jednaĉine, simulacija... indirectly associated with the forecasting process. This paper investigates the relationship between ore production rate, fixed costs, revenues, production costs, working days, and degree of use of production capacity, as input variables, and Degree of Operating Leverage (DOL) as indicator of ...
... reversion process, normal and uniform distribution. Geometric Brownian motion is used to define future values of production costs. Values of ore production rate, fixed costs, working days, and degree of use of production capacity are estimated by expert‘s knowledge. By simulating a forecasting ...Svetlana M. Štrbac-Savić. "Prognoza operativne efikasnosti aktivnog podzemnog rudnika zasnovana na teoriji sivih sistema" in Универзитет у Београду, Универзитет у Београду, Рударско-геолошки факултет (2016-06-10)
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Mechanosynthesis and structural characterization of nanocrystalline Ce1–Y O2– (x=0.1–0.35) solid solutions
Martin Fabián, Bratislav Antić, Vladimír Girman, Milica Vučinić-Vasić, Aleksandar Kremenović, Shigeru Suzuki, Horst Hahn, Vladimír Šepelák (2015)A series of nanostructuredfluorite-type Ce1–xYxO2–δ (0rxr0.35) solid solutions, prepared via highenergy milling of the CeO2/Y2O3mixtures, are investigated by XRD, HR-TEM, EDS and Raman spectroscopy. For thefirst time, complementary information on both the long-range and short-range structural features of mechanosynthesized Ce1–xYxO2–δ, obtained by Rietveld analysis of XRD data and Raman spectroscopy, is provided. The lattice parameters of the as-prepared solid solutions decrease with increasing yttrium content. Rietveld refinements of the XRD data reveal increase in microstrains in the host ceria ...Martin Fabián, Bratislav Antić, Vladimír Girman, Milica Vučinić-Vasić, Aleksandar Kremenović, Shigeru Suzuki, Horst Hahn, Vladimír Šepelák. "Mechanosynthesis and structural characterization of nanocrystalline Ce1–Y O2– (x=0.1–0.35) solid solutions" in Journal of Solid State Chemistry, Elsevier BV (2015). https://doi.org/10.1016/j.jssc.2015.06.027