Претрага
253 items
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Fizičko-hemijsko raspadanje krečnjaka ugrađenih u objekte Beogradske tvrđave i mogućnost konsolidacije
Maja Z. Franković (2022)Beogradska tvrđava, spomenik kulture od izuzetnog značaja za Republiku Srbiju, izgrađena je od krečnjaka badenske starosti. Njihova litološka heterogenost, u sadejstvu sa uticajima okruženja, rezultira visokim intenzitetima raspadanja. Korelacijom intrinzičnih sa ekstrinzičnim faktorima, definisani su fizičko-hemijski procesi raspadanja ugrađenih mikrofacija krečnjaka. Aplikacijom neorganskih konsolidanata na karbonatnoj bazi (nano-kreča i Ca-acetoacetata) i alkoksisilana, te korelacijom fizičko-mehaničkih svojstava pre i nakon tretmana, ispitana je efektivnost u pogledu zaustavljanja dekohezije krečnjaka. Određivanjem petroloških, tehničkih svojstava i mapiranjem formi raspadanja Mračne kapije kao ...krečnjaci, forme i intenziteti degradacije, fizičko-hemijsko raspadanje, konsolidacija, nano-kreč, Ca-acetoacetat, alkoksisilani, Mračna kapijaMaja Z. Franković. Fizičko-hemijsko raspadanje krečnjaka ugrađenih u objekte Beogradske tvrđave i mogućnost konsolidacije, Beograd : M. Franković, 2022
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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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The Effect of Gravel and Sand Mining on Groundwater and Surface Water Regimes — A Case Study of the Velika Morava River, Serbia
Milan Kresojević, Vesna Ristić Vakanjac, Dragan Trifković, Jugoslav Nikolić, Boris Vakanjac, Dušan Polomčić, Dragoljub Bajić (2023)Овај рад описује како неконтролисано и нелегално откопавање песка и шљунка може утицати на режим површинских и подземних вода на местима где постоји активна хидрауличка веза између њих, са студијом случаја реке Велике Мораве у Србији. Такође, промена геометрије попречног профила, као последица антропогених и природних фактора, отежава уливање ове реке за укључивање у водне токове Србије. Плодност Велике Мораве омогућила би развој речног саобраћаја како за трговачке бродове, тако и за пловила Речне флотиле Војске Србије. Корелације између ...Milan Kresojević, Vesna Ristić Vakanjac, Dragan Trifković, Jugoslav Nikolić, Boris Vakanjac, Dušan Polomčić, Dragoljub Bajić. "The Effect of Gravel and Sand Mining on Groundwater and Surface Water Regimes — A Case Study of the Velika Morava River, Serbia" in Water, MDPI AG (2023). https://doi.org/10.3390/w15142654
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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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Fragmentation Size Prediction of Blasted Material Using a Specialized Software for Drilling and Blasting
Stefan Milanović, Nikola Simić, Lazar Kričak, Milanka Negovanović, Nikola Đokić, Miljan Gomilanović (2024)Design and optimizing the drilling and blasting parameters, should fill the requirements for the capacity, fragmentation size, and technical characteristics of loading and transport equipment, and enable a safe work at the open pit. Besides mentioned, it also achieves the minimal impact on the environment of the open pit and decreases the negative effects on the environment, especially in the blast vibration and flyrock. To obtain the best possible blasting effects and consider all the factors, a specialized software is ...Stefan Milanović, Nikola Simić, Lazar Kričak, Milanka Negovanović, Nikola Đokić, Miljan Gomilanović. "Fragmentation Size Prediction of Blasted Material Using a Specialized Software for Drilling and Blasting" in The 55th International October Conference on Mining and Metallurgy, Mining and Metallurgy Institute Bor (2024). https://doi.org/10.5937/IOC24077M
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Definition of criteria and alternatives for choosing the optimal mining method deposits when applying multi: Criteria optimization, Belgrade, June 2024
Sanja Bajić, Dragoljub Bajić, Branko Gluščević, Radmila Gaćina, Josip Išek. "Definition of criteria and alternatives for choosing the optimal mining method deposits when applying multi: Criteria optimization, Belgrade, June 2024" in Podzemni radovi, Beograd, jun 2024, Centre for Evaluation in Education and Science (CEON/CEES) (2024). https://doi.org/10.5937/podrad2444071B
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Adaptive neuro-fuzzy prediction of operation of the bucket wheel drive based on wear of cutting elements
The capacity of the rotor excavator depends largely on the operation of the subsystem for digging. There is a great contribution to the correct and sharp teeth when the capacity is the highest. In the function of time, the teeth become clogged due to abrasive wear, or changes in their geometric shape. To analyze the bucket wheel drive in depend on wear of the cutting elements in this study adaptive neuro fuzzy inference system (ANFIS) approach was implemented. ANFIS ...Filip Miletić, Predrag D. Jovančić, Milos Milovančević, Dragan Ignjatović. "Adaptive neuro-fuzzy prediction of operation of the bucket wheel drive based on wear of cutting elements" in Advances in Engineering Software, Elsevier BV (2020). https://doi.org/10.1016/j.advengsoft.2020.102824
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Correlation Between Dynamic CBR and Compaction and Bearing Capacity of Pavement Foundation Layers
This paper presents a dynamic California Bearing Ratio (CBRd) device that can be used on a prepared pavement foundation layer to obtain a certain parameter of the tested material in the laboratory and in situ in a direct and fast way. For the selected natural material (gravel), it is shown that the laboratory CBRd can be used to estimate the compaction and bearing capacity, because it correlates well with the parameters of the standard and modifed Proctor compaction tests. ...korelacija parametara, donji slojevi saobraćajnica, laboratorijska i terenska ispitivanja, dinamički kalifornijski indeks nosivosti CBRd... material (gravel) embedded in the final layer of the substrate (subgrade). CBR;y is a complex measure of the strength of a material, and depends on factors such as the grain size distribution, shape, and roughness of the grain, water content, and compaction, and can be expressed in the range of 20% ...
... s"%, (2) where s is the amplitude of the CBR, piston settlement (mm), and p is the maximum amplitude of the dy- namic load (N/mm?). Several factors can affect the measured CBR, value, including the falling weight, height offall, size (di- ameter) of the plate, plate contact stress, type and location ...
... ing devices. The influence of the measurement depth was also identical, as required for correlation without unnecessary additional influencing factors. The tests were performed on a subgrade layer made of natural stone aggregate (gravel). The subgrade layer was constructed above the embankment layer ...Milan Bogdanović, Snežana Bogdanović, Dragoslav Rakić, Irena Basarić Ikodinović. "Correlation Between Dynamic CBR and Compaction and Bearing Capacity of Pavement Foundation Layers" in Soil Mechanics and Foundation Engineering, Springer Science and Business Media LLC (2024). https://doi.org/10.1007/s11204-024-09939-x
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Selection of Artificial Lift Methods: A Brief Review and New Model Based on Fuzzy Logic
Miroslav Crnogorac, Miloš Tanasijević, Dušan Danilović, Vesna Karović Maričić, Branko Leković (2020)Artificial lift methods have applications in oil wells where oil production is no longer possible due to natural reservoir energy, so this necessary energy is added by introducing lift methods. In order to achieve optimum production, the selection of an artificial lift method is very important. This paper uses fuzzy logic as a mathematical and conceptual model for selection of the optimal artificial lift method. The outcome or IF-THEN rules, as the central part of the model, is based ...... covered the topic of a gas-lift; Bill Capps described ESP; and Phil Wilson explained the HP [6]. As the main factors geographical and environmental restrictions were taken, the secondary factors were reservoir pressure, productivity index, the characteristics of reservoir fluids, and well productivity ...
... Choosing the optimal method is done by taking into account the parameters of reservoir and fluids, well type, environmental conditions, and economic factors (capital and operational costs). Final decisions on artificial lift methods are often made based on the following subject criteria: • These should ...
... Choosing the optimal method is done by taking into account the parameters of reservoir and fluids, well type, environmental conditions, and economic factors (capital and operational costs). Final decisions on artificial lift methods are often made based on the following subject criteria: e These should ...Miroslav Crnogorac, Miloš Tanasijević, Dušan Danilović, Vesna Karović Maričić, Branko Leković. "Selection of Artificial Lift Methods: A Brief Review and New Model Based on Fuzzy Logic" in Energies, MDPI AG (2020)
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Differently shaped nanocrystalline (Fe, Y)3O4 and its adsorption efficiency toward inorganic arsenic species
Biljana P Dojčinović, Boštjan Jančar, Lotfi Bessais, Aleksandar Kremenović, Nataša P Jović-Jovičić, Predrag T Banković, Dalibor M Stanković, Miloš Ognjanović, Bratislav V Antić (2019)Herein we report effects of partial substitution of Fe3+ by Y3+ in magnetite (Fe3O4) on morphology and inorganic arsenic species adsorption efficiency of the Fe3−xYxO4 nanoparticles formed. The series of Fe3−xYxO4 (x=0.00, 0.042 and 0.084, labeled as Y00, Y05 and Y10, respectively) was synthesized using co-precipitation followed by microwave-hydrothermal treatment (MW) at 200°C. With increase of yttrium content(xvalue), both the morphological inhomogeneity of the samples and the fraction of spinel nanorods as compared to spinel pseudospherical particles increased. By ...Biljana P Dojčinović, Boštjan Jančar, Lotfi Bessais, Aleksandar Kremenović, Nataša P Jović-Jovičić, Predrag T Banković, Dalibor M Stanković, Miloš Ognjanović, Bratislav V Antić. "Differently shaped nanocrystalline (Fe, Y)3O4 and its adsorption efficiency toward inorganic arsenic species" in Nanotechnology, IOP Publishing (2019). https://doi.org/10.1088/1361-6528/ab3ca2
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Long-term planning methodology for improving wood biomass utilization
The insufficiently developed forest management system is often followed by undeveloped forest resources supply chain and insufficient institutional support. These cause inefficient usage of fuel-wood as well as huge amounts of unused forest residues. In order to achieve optimal and long-term sustainable utilisation of biomass, an original methodology based on the interaction of mathematical optimization and backcasting approach has been developed. Mathematical optimization is used for both generation and consideration of techno-economic parameters of the forest biomass supply chain. ...Vladimir Vukašinović, Dušan Gordić, Marija Živković, Davor Koncalović, Dubravka Živković. "Long-term planning methodology for improving wood biomass utilization" in Energy, Elsevier BV (2019). https://doi.org/10.1016/j.energy.2019.03.105
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Influence of Initial Treatment on the Survival and Recurrence in Patients With Differentiated Thyroid Microcarcinoma
... influenced by recurrence (P = 0.0001), clinical stage (P = 0.0005), and patients’ age (P = 0.02) (Fig. 2BYD, respectively). However, other prognostic factors such as sex, histopathological tumor type, metastases at pre- sentation, type of the initial treatment, RAI therapy, and risk catego- ries showed no ...
... (Fig. 3C) and by initial treatment (P = 0.003) (Fig. 3D). However, there was no significant difference associated with the fol- lowing prognostic factors: multifocality of the tumor, histological type of the tumor, age, and sex (P = 0.1, P = 0.3, P = 0.8, and P = 0.6, respectively). DISCUSSION Dif ...
... Consistent with the larger studies of Hay et al16 (900 patients) and Ito et al28 (732 patients), our study showed that among several prognostic factors, recurrence, clinical stage, and patients’ age had a statistically significant influence on DSS (P = 0.0001, P = 0.0005, and P = 0.02, respectively) ...Jasna Mihailović, Ljubomir Stefanović, Ranka Stanković. "Influence of Initial Treatment on the Survival and Recurrence in Patients With Differentiated Thyroid Microcarcinoma" in Clinical Nuclear Medicine, Lippincott Williams & Wilkins (2013). https://doi.org/10.1097/RLU.0b013e3182872ed2
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Atmospheric exposure vs burying: influences on damage intensity of built-in kersantite in the monument of the Small Staircase (Belgrade, Serbia)
Proučavan je efekat „zatrpanog kamena“ na intenzitet procesa degradacije prisutnih na kersantitu koji je ugrađen u spomenik Malo stepenište. Istraživanja su vršena na uzorcima stene iz kamenoloma i na oštećenim kamenim blokovima ugrađenim u spomenik. Dok su neki delovi stepeništa bili pod zemljom 90 godina, većina kamenih elemenata je bila izložena različitim uslovima sredine i antropogenim uticajima. Urađeno je detaljno mapiranje trenutnog stanja spomenika kako bi se istražio uticaj “zatrpavanja” i kompleksne geometrije spomenika na tip propadanja i variranje ...Nevenka Novaković, Predrag Dabić, Vesna Matović. "Atmospheric exposure vs burying: influences on damage intensity of built-in kersantite in the monument of the Small Staircase (Belgrade, Serbia)" in Environmental Earth Sciences, Springer Science and Business Media LLC (2023). https://doi.org/10.1007/s12665-023-10794-6
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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 the Dependability of Continuous Subsystems in Coal Mines Using the Fuzzy Logic Approach
Nikola Stanić, Miljan Gomilanović, Petar Marković, Daniel Krzanović, Aleksandar Doderović, Saša Stepanović (2024)This study presents a unique model for assessing the dependability of continuous parts of combined systems in open-pit mining through the application of fuzzy logic. Continuous sub-systems as part of the combined system of coal exploitation in surface mines have the basic function of ensuring safe operation, high capacity with high reliability, and low costs. These subsystems are usually part of the thermal power plant’s coal supply system and ensure stable fuel supply. The model integrates various independent partial ...fuzzy logic, max-min composition, continuous part of combined system (CCS), open pit, mining, dependabilityNikola Stanić, Miljan Gomilanović, Petar Marković, Daniel Krzanović, Aleksandar Doderović, Saša Stepanović. "A Model for Determining the Dependability of Continuous Subsystems in Coal Mines Using the Fuzzy Logic Approach" in Applied Sciences, Basel, August 2024, MDPI (2024). https://doi.org/https://doi.org/10.3390/app14177947
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Synthesis and characterization of high-pressure and high-temperature sphene (CaTiSiO5)
Jelena Pantić, Vladimir Urbanovich, Vesna Poharc-Logar, Bojan Jokić, Marija Stojmenović, Aleksandar Kremenović, Branko Matović (2014)Sphene (CaTiSiO5), a calcium titanosilicate ceramic has been prepared from a powder mixture of CaCO3, TiO2 and SiO2 using vibro-milling for homogenization and activation of precursors. During the highpressure and high-temperature synthesis (HPS) process at 4 GPa and 1,200 °C, sphene undergoes into phase transition, from room-temperature phase P21/a to high-temperature phase A2/a. Evidence of that structural phase transition is given in this paper using infrared, Raman spectroscopy and X-ray powder diffraction. Rietveld refinement was employed to get the ...Jelena Pantić, Vladimir Urbanovich, Vesna Poharc-Logar, Bojan Jokić, Marija Stojmenović, Aleksandar Kremenović, Branko Matović. "Synthesis and characterization of high-pressure and high-temperature sphene (CaTiSiO5)" in Physics and Chemistry of Minerals, Springer Science and Business Media LLC (2014). https://doi.org/10.1007/s00269-014-0693-x
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Microstructural and magnetic properties of electrospun hematite/cuprospinel composites
Phase composition, microstructural and magnetic properties of electrospun hematite/cuprospinel composites were investigated. Samples were synthesized starting with 0 to 10 mol% of copper relative to iron. The round shape of reference electrospun fbres was preserved upon their heating up to 600 °C in air, whereas at 700 °C hollow substructure was additionally formed. In these reference samples the presence of hematite phase was detected by XRPD. A small amount (traces) of Fe3O4 /γ-Fe2O3 was also found, due to the ...Electrical and Electronic Engineering, Condensed Matter Physics, Atomic and Molecular Physics and Optics, Electronic, Optical and Magnetic MaterialsMira Ristić, Aleksandar Kremenović, Michael Reissner, Željka Petrović, Svetozar Musić. "Microstructural and magnetic properties of electrospun hematite/cuprospinel composites" in Journal of Materials Science: Materials in Electronics, Springer Science and Business Media LLC (2020). https://doi.org/10.1007/s10854-020-03526-0
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State and perspective of individual household heating in Serbia: A survey-based study
This paper presents the results of the household survey on individual household heating systems in Serbia. The survey was conducted in the period October to December 2020 with the participation of 1100 households with individual household heating systems. The information collected in the questionnaire can be separated into three main parts: basic household data, current heating system characteristics, and households’ perceptions and attitudes. The survey results provide unique and comprehensive information concerning individual household heating systems and the main ...Boban Pavlović, Dejan Ivezić, Marija Živković. "State and perspective of individual household heating in Serbia: A survey-based study" in Energy and Buildings, Elsevier BV (2021). https://doi.org/10.1016/j.enbuild.2021.111128
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A hundred years of Milutin Milanković's climate change theory - geological implications
Dejan Radivojević (2020)Миланковићева теорија циклуса објављена пре сто година је најважнија теорија у наукама које проучавају климу и имала је велики утицај на дисциплине које се баве Земљом. Ипак, његов рад је чекао више од педесет година да би добио потврду. Може се рећи да Миланковићев рад највећи утицај на геологију има у изради астрономске временске скале, подршци хипотези континенталног дрифта и палеоклиматологији. Добри резултати примене астрономске временске скале на неогене седименте иницирали су примену ове методе у мезозојским и у последње ...циклостратиграфија, астономска временска скала, геолошка временска скала, климатске промене, континентални дрифт... changes led to fruitful cooperation with Alfred We- gener who was searching for additional arguments to validate his continental drift hypothesis. The factors that cause climate changes enable insight to the geological past, but also the possibility to model the climate conditions which await us in the future ...
... Paleoredox changes across the Paleocene-Eocene Thermal Maxi- mum, Walvis Ridge (oDP Sites 1262, 1263, and 1266): Evidence from Mn and U enrichment factors. Paleo- ceanography, 25: PA4202. DEWEy, j. F., CANDE, S. & PITMAN, W. C. 1989. Tectonic evolu- tion of the India/Eurasia Collision zone. Eclogae ...Dejan Radivojević. "A hundred years of Milutin Milanković's climate change theory - geological implications" in Geološki anali Balkanskoga Poluostrva, Univerzitet u Beogradu, Rudarsko geološki fakultet (2020). https://doi.org/10.2298/GABP201125011R
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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 ...... it is necessary to adopt extensive systematic and organizational measures that provide insight into all of the possible negative and destructive factors that may affect the operation of an engineering system. Only thorough knowledge of the way a system operates and its correlation with other systems ...
... technological sense) can lead to a first-rate risk assessment of an individual component’s failure. Meticulous attention should be directed toward the factors that can cause a risky event, as well as toward the consequences and negative effects that can manifest after a failure. The consequences of a failure ...
... it is necessary to adopt extensive systematic and organizational measures that provide insight into all of the possible negative and destructive factors that may affect the operation of an engineering system. Only thorough knowledge of the way a system operates and its correlation with other systems ...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