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1601 items
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Natural two-dimensional pyrophyllite: Nanoscale lubricant, electrical insulator and easily-machinable material
Borislav Vasić, Radoš Gajić, Ivana Milošević, Žarko Medić, Marina Blagojev, Marko Opačić, Aleksandar Kremenović, Dejan Lazić (2022)Pyrophyllite, with the chemical formula Al2Si4O10(OH)2, is a naturally occurring and abundant van der Waals mineral belonging to the group of phyllosilicates. It is very soft, layered crystal used for sculpting and an excellent electrical and thermal insulator aimed for the operation at high pressure and temperature. Here, for the first time, two-dimensional (2D) pyrophyllite obtained by both mechanical and liquid phase exfoliation is presented and investigated at the nanoscale. The layered structure provides low friction coefficient of around ...Atomic force microscopy, Insulating properties, Nanofriction and wear, Natural two dimensional materials, Phyllosilicates, PyrophylliteBorislav Vasić, Radoš Gajić, Ivana Milošević, Žarko Medić, Marina Blagojev, Marko Opačić, Aleksandar Kremenović, Dejan Lazić. "Natural two-dimensional pyrophyllite: Nanoscale lubricant, electrical insulator and easily-machinable material" in Applied Surface Science, Elsevier BV (2022). https://doi.org/10.1016/j.apsusc.2022.155114
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A bilingual digital library for academic and entrepreneurial knowledge management
A generic knowledge management process of organization, storage and retrieval of knowledge can suitably be fitted in a digital library. In the digital and knowledge age digital libraries can be used in knowledge management to handle intellectual assets and support knowledge creation. A multilingual digital library either stores content in more than one language or provides multilingual query access to monolingual content. In Serbia 18 of 308 scientific journals regularly published are bi-lingual, with papers simultaneously being in English ...Ranka Stanković, Cvetana Krstev, Biljana Lazić, Dalibor Vorkapić. "A bilingual digital library for academic and entrepreneurial knowledge management" in Proceeding of 10th International Forum on Knowledge Asset Dynamics — IFKAD 2015: Culture, Innovation and Entrepreneurship: connecting the knowledge dots, Bari, Italy, 10-12 June 2015, Bari : IFKAD (2015)
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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
... structural cffect, where a structure/component of the drive assembly acts as a signal amplifier at a sensitive frequency, or a frequency that cannot be characterized as a diagnostic parameter. To prove a negative impact, primarily that of a worn rear support of the electromotor mount (increased ...
... the center of gravity of the electromotor. 2. Effect of high vibrations on electromotor as a result of poor condition of mount support A bucket wheel excavator is a highly-complex dynamic system with a large number of vibration sources. It is sufficiently elastic and features different degrees ...
... electromotor of a bucket wheel excavator as a result of intensified wear-and-tear of its mount support Vesna Damnjanović!, Predrag Jovančić?, Snežana Aleksandrovićž University of Belgrade – Faculty of Mining and Geology, Belgrade, Serbia ?2Corresponding author E-mail: !vesna.damnjanovic(a\rgf.bg.ac ...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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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... a % - b 200 - ii D tl/(:· AŠ |=} 180 - 70 //E?] “ (-P-4"| AAJA N B D/_T'Jč, ___160 – A “A Ee . PrO M “ A Š Š D n f Č ĆA A -- o B 140 ; _ [- Ž . A a 50 M ~ : AAA AA n 070 - BI A AAAA %Ž mpon-- D A Z AA _ |j A 0 7 O A ŠA -& W m 1 l 100 _Z A a A |} A 30 80 ii CBRa(%) a E iii ...
... performed on a subgrade layer made of natural stone aggregate (gravel). The subgrade layer was constructed above the embankment layer, which consist- ed of natural material (sand) in three layers with a thickness of 0.3 m. Spreading was performed in a layer with a thickness of 0.35 m under a loose condition ...
... Email: milan.bogdanovic(Ottpaqi.com. This paper presents a dynamic California Bearing Ratio (CBR,) device that can be usedon 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 ...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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A necessary and sufficient condition for an algebraic integer to be a Salem number
Dragan Stankov (2019)We present a necessary and sufficient condition for a root greater than unity of a monic reciprocal polynomial of an even degree at least four, with integer coefficients, to be a Salem number. This condition requires that the minimal polynomial of some power of the algebraic integer has a linear coefficient that is relatively large. We also determine the probability that an arbitrary power of a Salem number, of certain small degrees, satisfies this condition.Algebraic integer, the house of algebraic integer, maximal modulus, reciprocal polynomial, primitive polynomial, Schinzel-Zassenhaus conjecture, Mahler measure, method of least squares, cyclotomic polynomials... We present a necessary and sufficient condition for a root greater than unity of a monic reciprocal polynomial of an even degree at least four, with integer coefficients, to be a Salem number. This condition requires that the minimal polynomial of some power of the algebraic integer has a linear coefficient ...
... Stankov In [9] Vieira, extending a result of Lakatos and Losonczi [3], presented a sufficient condition for a self-reciprocal polynomial to have a fixed number of roots on the complex unit circle U = {z ∈ C : |z| = 1}. Let p(z) = adzd +ad−1zd−1 + · · ·+a1z +a0 be a d-th degree self-reciprocal polynomial ...
... 2l roots on U and these roots are simple. Here we present, in a sense, a result which lies in the opposite direction of a special case of this theorem. Namely, we shall prove the following Theorem 1.1. A real algebraic integer τ > 1 is a Salem number if and only if its minimal polynomial P (x) is ...Dragan Stankov. "A necessary and sufficient condition for an algebraic integer to be a Salem number" in Journal de theorie des nombres de Bordeaux (2019). https://doi.org/10.5802/jtnb.1076
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A Data Driven Approach for Raw Material Terminology
Olivera Kitanović, Ranka Stanković, Aleksandra Tomašević, Mihailo Škorić, Ivan Babić, Ljiljana Kolonja (2021)The research presented in this paper aims at creating a bilingual (sr-en), easily searchable, hypertext, born-digital, corpus-based terminological database of raw material terminology for dictionary production. The approach is based on linking dictionaries related to the raw material domain, both digitally born and printed, into a lexicon structure, aligning terminology from different dictionaries as much as possible. This paper presents the main features of this approach, data used for compilation of the terminological database, the procedure by which it has ...sirovine, rudarstvo, terminologija, rečnik, terminološka aplikacija, mobilna aplikacija, digitizacija, leksički podaci, korpusi, otvoreni povezani podaciOlivera Kitanović, Ranka Stanković, Aleksandra Tomašević, Mihailo Škorić, Ivan Babić, Ljiljana Kolonja. "A Data Driven Approach for Raw Material Terminology" in Applied Sciences, MDPI AG (2021). https://doi.org/10.3390/app11072892
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Resource-based WordNet Augmentation and Enrichment
In this paper we present an approach to support production of synsets for SerbianWordNet(SerWN)byadjustingPrincetonWordNet(PWN)synsetsusing several bilingual English-Serbian resources. PWN synset definitions were automatically translated and post-edited, if needed, while candidate literals for Serbian synsets were obtained automatically from a list of translational equivalents compiled form bilingual resources. Preliminary results obtained from a setof1248selectedPWNsynsetsshowthattheproducedSerbiansynsetscontain 4024 literals, out of which 2278 were offered by the system we present in this paper, whereas experts added the remaining 1746. Approximately one half of ...Ranka Stanković, Miljana Mladenović, Ivan Obradović, Marko Vitas, Cvetana Krstev. "Resource-based WordNet Augmentation and Enrichment" in Proceedings of the Third International Conference Computational Linguistics in Bulgaria (CLIB 2018), May 27-29, 2018, Sofia, Bulgaria, Sofia : The Institute for Bulgarian Language Prof. Lyubomir Andreychin, Bulgarian Academy of Sciences (2018)
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Frequency and Length of Syllables in Serbian
Marija Radojičić, Biljana Lazić, Sebastijan Kaplar, Ranka Stanković, Ivan Obradović, Ján Mačutek, Lívia Leššová (2019)Basic analyses of several properties of syllables (the rank-frequency distribution, the distribution of length, and the relation between length and frequency) in Serbian is presented. The syllabification algorithm used combines the maximum onset principle and the sonority hierarchy. Results indicate that syllables behave similarly to words as far as mathematical models are concerned, but values of parameters in models for syllables are quite different from those for words.Marija Radojičić, Biljana Lazić, Sebastijan Kaplar, Ranka Stanković, Ivan Obradović, Ján Mačutek, Lívia Leššová. "Frequency and Length of Syllables in Serbian" in Glottometrics (2019)
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Bilingual lexical extraction based on word alignment for improving corpus search
Jelena Andonovski, Branislava Šandrih, Olivera Kitanović. "Bilingual lexical extraction based on word alignment for improving corpus search" in The Electronic Library, Emerald (2019). https://doi.org/10.1108/EL-03-2019-0056
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3D modeling and monitoring of karst system as a base for its evaluation and utilization: a case study from eastern Serbia
Earth-Surface Processes, Geology, Pollution, Soil Science, Water Science and Technology, Environmental Chemistry, Global and Planetary ChangeSaša Milanović, Zoran Stevanović, Ljiljana Vasić, Vesna Ristić-Vakanjac. "3D modeling and monitoring of karst system as a base for its evaluation and utilization: a case study from eastern Serbia" in Environmental Earth Sciences, Springer Science and Business Media LLC (2013). https://doi.org/10.1007/s12665-013-2591-9
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A survey of greenhouse gases production in central European lignites
Anna Pytlak, Anna Szafranek-Nakonieczna, Weronika Goraj, Izabela Śnieżyńska, Aleksandra Krążała, Artur Banach, Ivica Ristović, Mirosław Słowakiewicz, Zofia Stępniewska (2021)Anna Pytlak, Anna Szafranek-Nakonieczna, Weronika Goraj, Izabela Śnieżyńska, Aleksandra Krążała, Artur Banach, Ivica Ristović, Mirosław Słowakiewicz, Zofia Stępniewska. "A survey of greenhouse gases production in central European lignites" in Science of The Total Environment, Elsevier (2021). https://doi.org/10.1016/j.scitotenv.2021.149551
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A Mathematical Learning Environment Based on Serbian Language Resources
In recent years, in line with ever growing usage of Information technology, the learning environments are changing. The amount of available learning materials in various forms has increased. These new environments demand comprehensive learning systems, which enable management of the learning corpus with special attention paid to relevant lexical resources. In this paper we present the concept of a Mathematical Learning Environment in Serbian (MLES), which is based on a corpus of mathematical materials and various lexical resources, enabling ...Radojičić Marija, Obradović Ivan, Stanković Ranka, Utvić Miloć, Kaplar Sebastijan. "A Mathematical Learning Environment Based on Serbian Language Resources" in Proceedings of the 7th International Scientific Conference Technics and Informatics in Education, Faculty of Technical Sciences, Čačak (2018)
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Laboratory Testing of Nanosilica- Reinforced Silicate and Polyacrylamide Gels
Irina Zahirovic, Dušan Danilović, Milica Šuput Vranjin, Miloš Tripković. "Laboratory Testing of Nanosilica- Reinforced Silicate and Polyacrylamide Gels" in SPE Journal (2023)
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The Usage of Various Lexical Resources and Tools to Improve the Performance of Web Search Engines
In this paper we present how resources and tools developed within the Human Language Technology Group at the University of Belgrade can be used for tuning queries before submitting them to a web search engine. We argue that the selection of words chosen for a query, which are of paramount importance for the quality of results obtained by the query, can be substantially improved by using various lexical resources, such as morphological dictionaries and wordnets. These dictionaries enable semantic ...LR web services, MultiWord Expressions & Collocations, Information Extraction, Information RetrievalKrstev Cvetana, Stanković Ranka, Vitas Duško, Obradović Ivan. "The Usage of Various Lexical Resources and Tools to Improve the Performance of Web Search Engines" in LREC 2008: Conference on Language Resources and Evaluation, Marrakesh, Morocco, May 2008, European Language Resources Association (ELRA) (2008)
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Development of terminological resources for expert knowledge: a case study in mining
... 15 20 25 30 35 40 fi n g e rs fo re a rm h a n d s h o u ld e r u p p e r a rm e y e fa c e h e a d ( o th ) a n k le fo o t k n e e s h a n k th ig h to e o th e r p a rt to rs o ( o th ) in te r. o rg a n s arm head leg torso 5 3 9 1 18 6 2 ...
... languages are linked, usually by a list of term pairs. Terminological resources featuring a hierarchy are taxo- nomies. If richer semantic relations exist between con- cepts, the terminological resource becomes either a thesaurus or an ontology. While opinions exist that a clear boundary between the ...
... 2012). One of the means to secure interoperability within a specific domain is the use of ontologies, containing a comprehensive common domain vocabulary. In other words, all terms used within a domain need to be standar- dized, with a clear and unambiguous definition, accompa- nied by lexical ...Ljiljana Kolonja, Ranka Stanković, Ivan Obradović, Olivera Kitanović, Aleksandar Cvjetić. "Development of terminological resources for expert knowledge: a case study in mining" in Knowledge Management Research & Practice, Palgrave Macmillan (2015). https://doi.org/10.1057/kmrp.2015.10
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Digital Library From A Domain Of Criminalistics As A Foundation For A Forensic Text Analysis
U ovom radu predstavljen je model koji omogućava prikupljanje, pripremu, opis metapodataka, upravljanje i eksploataciju, uključujući pretragu punog teksta dokumenata iz domena kriminalistike napisanih na srpskom jeziku. Predloženi pristup primenjuje se na veb portalu koji sakuplja različite tekstove nastale iz časopisa Akademije za kriminalistiku i policijske studije, Krivičnog zakona Srbije, konferencija „Tara“ i „Reiss“, kao i iz nekih doktorskih disertacija vezanih za ovu oblast istraživanje. Nakon obrade teksta, korpus koji sadrži preko 5500 stranica običnog teksta, kreiran je i ...Dalibor Vorkapić, Aleksandra Tomašević, Miljana Mladenović, Ranka Stanković, Nikola Vulović. "Digital Library From A Domain Of Criminalistics As A Foundation For A Forensic Text Analysis" in International Scientific Conference “Archibald Reiss Days” Thematic Conference Proceedings Of International Significance, Belgrade, 7-9 November 2017, Academy Of Criminalistic And Police Studies Belgrade (2017)
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Flotability of chalcopyrite from the Rudnik deposit
Директно селективно флотирање олова, бакра и цинка у флотацији рудника „Рудник” датира од 1984. године. Технолошка шема омогућава директно издвајање селективних концентрата у три циклуса. У првом циклусу се издваја минерал олова (галенит), док су минерал бакра (халкопирит) и минерал цинка (марматит) депримирани. У другом циклусу се оток концентрације минерала олова кондиционира и припрема за издвајање минерала бакра. Након кондиционирања, у овом циклусу се издваја минерал бакра. У трећем циклусу се оток концентрације минерала бакра кондиционира и припрема за ...... achieved at a pH of 6.20. Increasing the pH to 7.20 leads to a sharp decrease in chalcopyrite recovery to 38.82%. A further increase in the pH to 8.20 leads to a sharp increase in the recovery of chalcopyrite to 72.24%, which is the second maximum. Increasing the pH value to 9.20 leads to a sharp decrease ...
... of the magnetic stirrer. In flotation experiments, a reagent from the xanthate group, potassium amyl xanthate (KAX), was used as a collector. Sodium cyanide (NaCN) reagent was used as a depressant. Aqueous solutions of these reagents, at a concentration of 1 g/L, were added to the flotation cell ...
... - Flotability of chalcopyrite as a function of pulp pH, at a consumption of KAX of 4 mg/L pH Recovery [%] 6.20 96.21 7.20 64.56 8.20 87.90 9.20 86.06 10.20 68.37 Figure 3 - Flotability of chalcopyrite from"Rudnik" mine as a function of pulp pH, at a consumption of KAX of 4 mg/L ...Đurica Nikšić, Predrag Lazić, Milena Kostović. "Flotability of chalcopyrite from the Rudnik deposit" in Journal of Mining Science, Springer Verlag (2021). https://doi.org/10.1134/S1062739121030170
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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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Fuzzy expert analysis of the severity of mining machinery failure
Mining machinery failure is almost an everyday occurrence. Usually the failures bare certain consequences, which require additional financial costs to repair and restore the system to its operational state. The consequences are viewed through negative and damaging effects a failure has on the machine, health and safety of the employees, work environment, and on the environment. The removal of the consequences of the failure requires additional financial investment, which has a negative impact on the company’s business. In order ...... ery failure Dejan V. Petrović a,∗, Miloš Tanasijević b, Saša Stojadinović a, Jelena Ivaz a, Pavle Stojković a a University of Belgrade, Technical Faculty in Bor, VJ 12, Bor, Serbia b University of Belgrade, Faculty of Mining and Geology, Djusina 7, Belgrade, Serbia a r t i c l e i n f o Article history: ...
... significance of severity of a failure as a risk indicator especially in mining sector. Consid- ering the failure severity through negative effects of a machine failure provides the higher reliability of a risk assessment model. The ultimate goal of this research is a development of a risk assessment model ...
... failure is a complex task that includes a number of causes and effects pertaining to a risky event, based on which conclusions about the observed phenomenon can be drawn. The risk of mining machinery failure is always present, es- pecially in industrial systems that have been in use for a long time. ...Dejan V. Petrović, Miloš Tanasijević, Saša Stojadinović, Jelena Ivaz, Pavle Stojković. "Fuzzy expert analysis of the severity of mining machinery failure" in Applied Soft Computing, Elsevier BV (2020). https://doi.org/10.1016/j.asoc.2020.106459
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On the distribution modulo 1 of the sum of powers of a Salem number
Dragan Stankov (2016)It is well known that the sequence of powers of a Salem number θ, modulo 1, is dense in the unit interval, but is not uniformly distributed. Generalizing a result of Dupain, we determine, explicitly, the repartition function of the sequence , where P is a polynomial with integer coefficients and θ is quartic. Also, we consider some examples to illustrate the method of determination.Algebraic integer, the house of algebraic integer, maximal modulus, reciprocal polynomial, primitive polynomial, Schinzel-Zassenhaus conjecture, Mahler measure, method of least squares, cyclotomic polynomials... (i) find a set A of local minimum points, a set B of local maximum points, and a set S of (horizontal inflection) stationary points on [−1, 1] of Q (x); (ii) find a set A of fractional parts of values at local minimum points, a set B of fractional parts of values at local maximum points, and a set S ...
... in R/Z. A Pisot number is a real algebraic integer greater than 1 whose other conjugates have modulus less than 1. A Salem number is a real algebraic integer greater than 1 whose other conjugates have modulus less than or equal to 1 and a conjugate with modulus one. It is easy to see that a E-mail ...
... distribution modulo 1 of the sum of powers of a Salem number Sur la répartition modulo 1 de la somme des puissances d’un nombre de Salem Dragan Stankov Katedra Matematike RGF-a, University of Belgrade, Beograd, Ðušina 7, Serbia a r t i c l e i n f o a b s t r a c t Article history: Received 1 February ...Dragan Stankov. "On the distribution modulo 1 of the sum of powers of a Salem number" in Comptes rendus Mathematique (2016). https://doi.org/10.1016/j.crma.2016.03.012