Претрага
497 items
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Determination of Mechanical Properties of Altered Dacite by Laboratory Methods
This paper presents a methodology for determining the uniaxial and triaxial compressive strength of heterogeneous material composed of dacite (D) and altered dacite (AD). A zone of gradual transition from altered dacite to dacite was observed in the rock mass. The mechanical properties of the rock material in that zone were determined by laboratory tests of composite samples that consisted of rock material discs. However, the functional dependence on the strength parameter alteration of the rock material (UCS, intact ...... tly influenced by microstructural characteristics, the most important of which are: the participation of the main mineral elements [12], mineral grain size [13], arrangement of mineral grains and their shape [14], mutual contact between individual mineral grains [15], and level of alteration [16]. In ...
... and AD samples showed that sanidine and quartz predominate in D. The strength parameters of the rock material are affected mainly by the content and size of quartz crystals. So, as the content of smaller quartz particles increases, the compressive strength increases. In the AD sample, the process of quartz ...
... separate discs [4] was shown as inadequate due to plaster failure at lower loads, causing the discs to displace and introducing non-uniform stress distribution throughout the disc interfaces. Tziallas et al. [1] found that the use of plaster to connect separate discs is unnecessary, considering the pattern ...Veljko Rupar, Vladimir Čebašek, Vladimir Milisavljević, Dejan Stevanović, Nikola Živanović. "Determination of Mechanical Properties of Altered Dacite by Laboratory Methods" in Minerals, MDPI AG (2021). https://doi.org/10.3390/min11080813
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Post Early Miocenevertical-axis clockwise rotation in the West Vardar Zone of Serbia
... both of Oligocene age. Samples were drilled and oriented in situ both by magnetic and sun compasses. In the laboratory samples were cut into standard size specimens, then subjected to standard paleomagnetic measurements which included the measurement of the natural remanent magnetization, followed by ...Vesna Lesić, Emo Marton, Vesna Cvetkov, Dragana Jovanović. "Post Early Miocenevertical-axis clockwise rotation in the West Vardar Zone of Serbia " in Environmental, Structural and Stratigraphical Evolution of the Western Carpathians, 11th ESSEWECA Conference, Geophysical Institute, Slovak Academy of Sciences Bratislava (2018)
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Geoloski profil planine Avale (severna Šumadija) - uvid u litostratigrafiju i tektonske strukture
Mezozojske formacije Šumadije dele tektonsko-stratigrafsku evoluciju južnijih delova suture jedinica Adrijskog i Evropskog afiniteta, uključujući gornjojursku obdukciju, krednu subdukciju i paleogenu kontinentalnu koliziju. Finalni rezultat dugovremene evolucije u geodinamički složenom ambijentu su komplikovani tektonski i litostratigrafski odnosi različitih mezozojskih formacija suture. Geološki profil kroz planinu Avalu omogućava uvid u skoro potpunu sukcesiju mezozojskih formacija i prostorne pozicije i kinematiku značajnih tektonskih struktura najsevernijih segmenata suture u Šumadiji. U tektonskom kontekstu, mezozojske formacije okoline Beograda najčešće su interpretirane kao deo Istočne ...Marinko Toljić, Bojan Glavaš-Trbić, Maja Maleš, Nikola Ranđelović. "Geoloski profil planine Avale (severna Šumadija) - uvid u litostratigrafiju i tektonske strukture" in 18. Kongres geologa Srbije "Geologija rešava probleme", Divčibare, 01-04 jun 2022. , Srpsko geološko društvo (2022)
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Српски језик у дигиталном добу -- The Serbian Language in the Digital Age
Duško Vitas, Ljubomir Popović, Cvetana Krstev, Ivan Obradović, Gordana Pavlović-Lažetić, Mladen Stanojević (2012)... of domains, number and size of existing speech corpora, amount and va- riety of available speech-based applications ‚ Machine Translation: uality of existing MT tech- nologies, number of language pairs covered, cover- age of linguistic phenomena and domains, quality and size of existing parallel corpora ...
... and do- mains, amount and variety of available applications, quality and size of existing (annotated) text corpora, quality and coverage of existing lexical resources (e. g., WordNet) and grammars ‚ Resources: uality and size of existing text corpora, speech corpora andparallel corpora, quality and ...
... generated from these words. 3.2.4 Syntax, text linguistics In terms of distribution of sentence constituents (sub- ject, predicate, object, etc.), Serbian belongs to SVO languages with free word order (more precisely, with free distribution of mobile sentence constituents). is means that, in general, all ...Duško Vitas, Ljubomir Popović, Cvetana Krstev, Ivan Obradović, Gordana Pavlović-Lažetić, Mladen Stanojević. "Српски језик у дигиталном добу -- The Serbian Language in the Digital Age" in META-NET White Paper Series, G. Rehm, H. Uszkoreit (eds.), Springer (2012)
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Mesozoic carbonate rocks in Serbia used as dimension stone
Vesna Matović, Tijana Vojnović Ćalić (2016)The building industry in Serbia uses, to a great extent, imported natural stone for architectural purposes. The significance of local deposits, particularly limestones, is not adequately perceived despite the country’s abundance of these valuable resources. Therefore, this study focuses on Serbia’s Mesozoic carbonate rocks, specifically on the deposits of four selected quarries: Klisura, Skrzut, Struganik, and Tisnica. The quality and prospects of the application of these limestones has not yet been the subject of a detailed, comprehensive investigation. Therefore, ...... crucial criterions for the profitable production of dimension stone are the soundness of the deposit (possibility of block production of a suitable size) and market demand (Luodes et al. 2000). Despite the fact that concrete and glass were the prin- cipal materials in architectural design during ...
... y, the rock mass is fragmented into blocks by a system of faults and fractures that reduce the possibility of extracting blocks of commercial size. The Struganik quarry has been exploited for architectural stone for over three decades. It is situated in western Serbia, within the territory ...
... light connected to a Leica DC 300 digital camera. The thin sections were used to determine the mineral composition and microtextural features (size and type of allochem) for the purpose of rock classification, according to Folk (1959) and Flugel (2004). The CaO and MgO contents were determined ...Vesna Matović, Tijana Vojnović Ćalić. "Mesozoic carbonate rocks in Serbia used as dimension stone" in Bulletin of Engineering Geology and the Environment, Springer Science and Business Media LLC (2016). https://doi.org/10.1007/s10064-015-0722-0
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Towards Better Valorisation of Industrial Minerals andRocks in Serbia—Case Study of Industrial Clays
... ogy and the achieved results. Table 3. Perspective deposits of bentonite and bentonite clays in Serbia [53]. Size of deposit after [44]. None of these deposits are in operation. Deposit Size of Deposit Quality (Grade) Method of Exploitation Number of Layers and Their Thickness (M) Depth ...
... deposits, bedded and lenticular, with uniform structure, thickness, and quality of mineral raw materials 100–150 150–200 300–400 Deposits of medium size, bedded and lenticular, with uniform structure, thick- ness, and quality of mineral raw mate- rial 50–100 100–200 200–300 2 Large deposits, ...
... and lenticular, without uniform structure and thick- ness, with variable quality of mineral raw materials - 50–100 100–200 Deposits of medium size, bedded and lenticular, without uniform structure - 25–50 50–150 Resources 2021, 10, 63 7 of 18 and thickness, with variable quality of ...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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Application of the Fuzzy Model in the Evaluation and Selection of Hydraulic Excavators on Open-Pit Lignite Mine
Stevan Đenadić, Miloš Tanasijević, Vladimir Milisavljević, Dragan Ignjatović, Predrag Jovančić (2021)The production of lignite in large open-pit mines is mainly performed with continuously operating equipment, where bucket-wheel excavators, bucket-chain excavators, belt conveyors, and spreaders are the basic machines. Smaller machines, usually of discontinuous operating nature, are commonly categorized as auxiliary machines. This paper presents the research related to the analysis of auxiliary machine parameters with the case study for a hydraulic excavator. The purpose of the analysis was to develop a model of rating quality of service of the ...Stevan Đenadić, Miloš Tanasijević, Vladimir Milisavljević, Dragan Ignjatović, Predrag Jovančić. "Application of the Fuzzy Model in the Evaluation and Selection of Hydraulic Excavators on Open-Pit Lignite Mine" in SSRN Electronic Journal, Elsevier BV (2021). https://doi.org/10.2139/ssrn.3945617
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Application of machine learning for diagnosing the operation of a deep well pump in oil production
Maja Trikić (2024)This paper will thoroughly examine how machine learning can improve the diagnosis of deep well pumps by analyzing the role and function of the pumps, dynamograms, sensor technologies, and diagnostic methods.Our analysis will provide insights into modern techniques and approaches for enhancing the performance and reliability of oil production systems, targeting cost reduction and increased operational efficiency.deep well pump, dynamograms, machine learning, diagnostics of operating coditions,Random Forest, XGBoost... tree, Random forest and XGBoost AutoML Decision tree, Random forest and XGBoost Decision tree Number of instances per class 30 30 90 180 Test set size 50,098 50,098 50,098 50,098 Number of tests 9 3 9 3 Maximum accuracy (%) 86.005 84.516 97.900 98.174 Table 3. Organization of Tests into 4 Groups ...
... card can indicate the performance of the pump system. However, since sensors are located at the surface, degenerative effects caused by load distribution along the rod string can alter the card's shape, complicating analysis, especially in deep wells. Due to these challenges and the difficulty ...
... is important to use metrics that combine precision and recall. 6.3.2. Imbalanced datasets Imbalanced datasets refer to situations where the distribution of examples among different classes is not even or is biased. Most machine learning algorithms assume that classes are approximately equal in ...Maja Trikić. Application of machine learning for diagnosing the operation of a deep well pump in oil production, 2024
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Automatic construction of a morphological dictionary of multi-word units
The development of a comprehensive morphological dictionary of multi-word units for Serbian is a very demanding task, due to the complexity of Serbian morphology. Manual production of such a dictionary proved to be extremely time-consuming. In this paper we present a procedure that automatically produces dictionary lemmas for a given list of multi-word units. To accomplish this task the procedure relies on data in e-dictionaries of Serbian simple words, which are already well developed. We also offer an evaluation ...electronic dictionary, Serbian, morphology, inflection, multiwordn units, noun phrases, query expansion... methodology and format known as DELAS/DELAF, which is presented for French in [1]4. Serbian e-dictionaries of simple forms have reached a consid- erable size: they have a total of 122,000 entries [2]. Although we are continually enlarging our e-dictionaries of simple words, we have taken a further step to- ...
... whereas for French it is 1.29. The calculation is performed on the basis of dictionaries described in [10] and [11] that are part of the standard distribution of Unitex [12], a corpus processing system based on the finite-state technology. 4 Authors Suppressed Due to Excessive Length Table 1. Initial ...Cvetana Krstev, Ranka Stanković, Ivan Obradović, Duško Vitas, Miloš Utvić. "Automatic construction of a morphological dictionary of multi-word units" in Lecture Notes in Computer Science 6233, Advances in Natural Language Processing, Proceedings of the 7thInternational Conference on NLP, IceTAL 2010, Reykjavik, Iceland, August 2010, Springer (2010): 226-237. https://doi.org/10.1007/978-3-642-14770-8_26
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Definition of groundwater genesis and circulation conditions of the complex hydrogeological karst system Mlava–Belosavac–Belosavac-2 (eastern Serbia)
Ljiljana Vasić, Saša Milanović, Zoran Stevanović, Laszlo Palcsu. "Definition of groundwater genesis and circulation conditions of the complex hydrogeological karst system Mlava–Belosavac–Belosavac-2 (eastern Serbia)" in Carbonates and Evaporites, Springer Science and Business Media LLC (2020). https://doi.org/10.1007/s13146-020-00550-3
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Izdvajanje vode iz prirodnog gasa
Dejan Nedeljkov (2024)U radu je istaknuto važnost prirodnog gasa kao vitalna komponenta svetske energetike.Spada u najsigurnije,najčistije i najkorisnije fosilno gorivo. Sama pojava vode u vidu vlage u gasu je pokazatelj lošeg kvaliteta gasa. parametri koji mogu dovesti do lošeg kvaliteta prirodnog gasa kao pokazatelj je Wobbe index.U okviru istraživanja u master radu glavni problem funkcionisanja na KPG Paliću predstavlja vlaga u gasu,takođe se može zaključiti da kvalitet gasa zavisi od Wobbe indeksa odnosno, što je Wobbe veći, čistiji je gas, ili ...... TM O n BR O O — 5 A.P. Szilas: Production and Transportation od Oil and Gas, Elsevier, Budapest, 1986,str.108 % Artur Gerunda: How to Size Liquid — vapor separators, Chemical Enginering,str.89 9 5. SAKUPLJANJE, SEPARACIJA, PRIPREMA I TRANSPORT GASA Sabirno - transportni sistem čine ...
... separatori zbog toga se daje upoređenje njihovih karakteristika. !' Ken Ranold, Maurice Steward: Designing oil and gas production system – How to size and select three phase separators, World Oil, Decembar, 1984., str. 68 18 Horizontalni separatori su produktivniji i efikasniji od vertikalnih ...
... IIL, 2012. godine [11] A.P. Szilas: Production and Transportation od Oil and Gas, Elsevier, Budapest, 1986. godine [12] Artur Gerunda: How to Size Liquid – vapor separators, Chemical Enginering. [13] Andre Giraud, Xavier BOY: Geopolitique du petrol et du gaz, Edition Technip, Paris, 1987. godine ...Dejan Nedeljkov . Izdvajanje vode iz prirodnog gasa, 2024
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Review: Methodological approaches and research techniques for addressing construction and remediation problems in karst reservoirs
Saša Milanović, Ljiljana Vasić (2021)Saša Milanović, Ljiljana Vasić. "Review: Methodological approaches and research techniques for addressing construction and remediation problems in karst reservoirs" in Hydrogeology Journal, Springer Science and Business Media LLC (2021). https://doi.org/10.1007/s10040-020-02280-1
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NMR kinetic studies of the interactions between [Ru(terpy)(bipy)(H2O)]2+ and some sulfur-donor ligands
Aleksandar Mijatović, Biljana Šmit, Ana Rilak, Biljana Petrović, Dragan Čanović, Živadin D. Bugarčić (2012)Reakcije supstitucije monofunkcionalnog [Ru(terpi)(bipi)(H2O)]2+ kompleksa, gde je terpi = 2,2′:6′,2″-terpiridin i bipi = 2,2′-bipiridin, sa biološki relevantnim sumporo donorskim ligandima, kao što su tiourea, l-metionin, l-cistein i glutation, proučavane su u vodenim rastvorima tehnikom 1H i 13C NMR spektroskopije. Sve reakcije su proučavajne na pH 7,4, u prisustvu fosfatnog pufera, da bi se oponašalo fiziološko okruženje tokom procesa supstitucije. Reakcije se izvode na 295 K pod uslovima reakcija drugog reda. Uočeni rezultati pokazuju da brzina supstitucije snažno zavisi ...Aleksandar Mijatović, Biljana Šmit, Ana Rilak, Biljana Petrović, Dragan Čanović, Živadin D. Bugarčić. "NMR kinetic studies of the interactions between [Ru(terpy)(bipy)(H2O)]2+ and some sulfur-donor ligands" in Inorganica Chimica Acta, Elsevier BV (2012). https://doi.org/10.1016/j.ica.2012.09.016
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Extensive vibrations of the belt conveyer drive electromotor of a bucket wheel excavator as a result of intesified wear-and-tear of its mount support
Vesna Damnjanović, Predrag Jovančić, Snežana Aleksandrović. "Extensive vibrations of the belt conveyer drive electromotor of a bucket wheel excavator as a result of intesified wear-and-tear of its mount support" in Journal of Vibroengineering (2017). https://doi.org/10.21595/jve.2016.17321
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Structural characterization of traditional pottery produced from local clay, Rujište (Ražanj, Central Serbia), in an effort to preserve its geoheritage
... spectrometer (EDS), a wavelength-dispersive spectrometer (WDS) and a cathodoluminescence detector (CL) were applied to determine the morphology and grain size assessment of minerals as well as their chemical composition. Raw clay, from which investigated sample of pottery was produced, largely falls ...Maja Milošević, Biljana Đorđević, Alena Zdravković . "Structural characterization of traditional pottery produced from local clay, Rujište (Ražanj, Central Serbia), in an effort to preserve its geoheritage" in 9th International Conference Mineralogy and Museums, Sofia, Bulgaria, Earth and Man National Museum and Bulgarian Mineralogical Society (2021)
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Influence of Ag doping on the morphological and magnetic properties in CuO nanopowders
Maria Čebela, Uroš Čakar, Vesna Lojpur, Maja Milošević, Sanja Krstić, Vladimir Dodevski, Milena Rosić (2023)... Ag in order to improve further its multiferroic properties. Compared with CuO, we observed small changes in magnetic properties in Cu, „Ag,O. The size and morphology of the particles were successfully determined by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). ...Maria Čebela, Uroš Čakar, Vesna Lojpur, Maja Milošević, Sanja Krstić, Vladimir Dodevski, Milena Rosić. "Influence of Ag doping on the morphological and magnetic properties in CuO nanopowders" in Programme ; and the Book of Abstracts / 7th Conference of The Serbian Society for Ceramic Materials, 7CSCS-2023, June 14-16, 2023 Belgrade, Serbia , Beograd : Institut za multidisciplinarna istraživanja, (2023)
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Definition of Circulation Conditions and Groundwater Genesis of the Complex Krupaja Hydrogeological Karst System (Eastern Serbia)
Management, Monitoring, Policy and Law,Renewable Energy, Sustainability and the Environment, Geography, Planning and Development, Building and Construction... form 3D models of karst channels, which has led to the development of completely new techniques and programs for the purpose of analyzing the distribution and position of karst channels within a karst system [4-7]. An important tool for defining , the velocity of groundwater circulation and mean ...
... multi-parameter research concept was applied. Previous research was focused on creating, a spatial model of the Krupaja Spring, karst channel distribution, i.e., through investigation of the part of the karst aquifer in which rapid circulation and water exchange takes place, the part of the aquifer ...
... defining, the main directions and orientation of karst conduits (followed by a possible small percentage error), layers of potential 3D karst channel distribution were created. The total length of the karst channel network, which was calculated using, this model and presented in a 3D environment, is 647 ...Ljiljana Vasić, Saša Milanović, Tina Dašić. "Definition of Circulation Conditions and Groundwater Genesis of the Complex Krupaja Hydrogeological Karst System (Eastern Serbia)" in Sustainability, MDPI AG (2023). https://doi.org/10.3390/su151411146
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Callovian (Middle Jurassic) Sphriganaria (Brachiopoda) from the Jordan Valley (Middle East)
Howard R. Feldman, Barbara V. Radulović, Fayez Ahmad. "Callovian (Middle Jurassic) Sphriganaria (Brachiopoda) from the Jordan Valley (Middle East)" in Historical Biology (2023). https://doi.org/10.1080/08912963.2022.2122823
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Dehydroicetexanes in sediments and crude oils: Possible markers for Cupressoideae
Hans Peter Nytoft, Geir Kildahl-Andersen, Sofie Lindström, Frode Rise, Achim Bechtel, Danica Mitrović, Nataša Đoković, Dragana Životić, Ksenija A. Stojanović (2019)Two previously unidentified dehydroabietane isomers were isolated from Miocene Serbian lignite and Rhaetian (Late Triassic) coaly mudstones from South Sweden and characterized using NMRspectroscopy as cis- and trans-dehydroicetexane. Both have a 9(10?20)-abeo-abietane or icetexane skeleton, consisting of a 6-7-6 tricyclic framework with seven carbons in ring B instead of the usual six in common diterpanes of the abietane-type. Dehydroicetexanes can be detected using GC-MS-MS in m/z 270?146 chromatograms without interference from dehydroabietane or other isomers. Dehydroicetexanes are often abundant ...Hans Peter Nytoft, Geir Kildahl-Andersen, Sofie Lindström, Frode Rise, Achim Bechtel, Danica Mitrović, Nataša Đoković, Dragana Životić, Ksenija A. Stojanović. "Dehydroicetexanes in sediments and crude oils: Possible markers for Cupressoideae" in Organic Geochemistry, Elsevier BV (2019). https://doi.org/10.1016/j.orggeochem.2019.01.001
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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 ...... deviations in the behavior of the observed phenomenon. In such cases, it is necessary to disturb the symmetry of the particular areas in relation to the size of j. An example of a non-symmetric outcome can be seen in [27], where the outcomes were ranked. Symmetry 2020, 12, 525 7 of 26 Figure 2. Fuzzy ...
... downtime from machinery failure (obtained based on a timeline of the technical system’s state through the application of Weibull’s two-parameter distribution), t = t1, . . . , tn, undergo a process of fuzzification into trapezoidal fuzzy numbers with the parameter values 1 < β < 3 (Figure 3) (it is best ...
... allocated time for breakpoints bp2 and bp3 is calculated based on the mean time (T), which depends on the shape parameter β in a standard Weibull distribution [29]. Bp2 = T − x·(T − t1), (3) bp3 = T + x·(tn − T), (4) where: x = 0 for β = 3 and x = 1 for β = 1. The proportion factor x can be determined ...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