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367 items

  • Kinetics, mechanism, and equilibrium studies of the reactions between a ruthenium(II) complex and some nitrogen- and sulfur-donor nucleophiles

    Aleksandar M. Mijatović, Ratomir M. Jelić, Jovana Bogojeski, Živadin D. Bugarčić, Biljana Petrović (2013)
    Kinetika i mehanizam reakcija supstitucije između [Ru(trpi)(bpi)Cl]+ sa nukleofilima gvanozin-5′-monofosfatom, L-histidinom, tioureom i dimetilsulfoksidom proučavani su spektrofotometrijski u 0,1 M NaClO4 na 310 K. Red reaktivnosti za odabrane ligande je: tiourea > gvanozin-5′-monofosfat > L-histidin > DMSO. Ovaj red je povezan sa elektronskim, strukturnim i hemijskim karakteristikama kompleksa i nukleofila. Reakcija supstitucije sa tioureom je proučavana na tri različite temperature (288, 298 i 310 K). Negativna entropija aktivacije DS = potvrđuje asocijativni način aktivacije. Formiranje kompleksa [Ru(trpi)(bpi)H2O]2+ sa ligandima ...
    Kinetika, Ravnoteža, Ru(II), L-Histidin, Guanozin-5' -monofosfat, Dimetilsulfoksid, Tiourea
    ... already published for some Ru(II) complexes [9, 26]. After formation of an adduct where the metal ion is coordinated to oxygen from the phosphate group, very slow isomerization to the N7 atom of purine takes place. The reaction with amino acid L-His could also proceed in a similar way by coordination ...
    ... predicted. One of themost important facts is knowledge of their ‘‘hard’’ and ‘‘soft’’ behavior. The ruthenium compounds belong to the ‘‘border line’’ group, whichmeans that they are somehow [Ru(trpy)(bpy)Cl] Scheme 1 + + L [Ru(trpy)(bpy)L]+ + Cl- L = 5'-GMP, L-His, Tu, DMSO k2 ...
    ... tration at pH = 4. This ion is assumed to form through the dimerization of [Ru(trpy)(bpy)H2O] 2? and [Ru(trpy)(bpy) (OH)]? complexes via the hydroxo group as shown in Eq. (4). The [Ru(trpy)(bpy)(OH)]? ion begins to form at pH = 2 and reaches the maximum in concentration at pH = 8. The complex ion [ ...

  • The ‘Umka’ landslide

    Uroš Đurić, Dragana Đurić, Miloš Marjanović, Biljana Abolmasov, Ivana Vasiljević (2024)
    We present an in-depth landslide map of the ‘Umka’ landslide near Belgrade, Serbia, at a scale of 1:5000. The map delineates elements at risk, primarily buildings and road infrastructure impacted by the landslide displacements of several cm per year, introduced during frequent reactivation stages. The Main map results from a survey of over 350 buildings and more than 7 km of state and local roads. The acquisition techniques included engineering geological field mapping, building survey, and visual interpretation of ...
    rizik od klizišta, elementi rizika, kartiranje pomoću drona, ispitivanje objekata, geotehnički monitoring

  • A Twitter Corpus and Lexicon for Abusive Speech Detection in Serbian

    Danka Jokić, Ranka Stanković, Cvetana Krstev, Branislava Šandrih (2021)
    Uvredljivi govor na društvenim medijima, uključujući psovke, pogrdni govor i govor mržnje, dostigao je nivo pandemije. Sistem koji bi bio u stanju da detektuje takve tekstove mogao bi da pomogne da internet i društveni mediji postanu bolji virtuelni prostor sa više poštovanja. Istraživanja i komercijalna primena u ovoj oblasti do sada su bili fokusirani uglavnom na engleski jezik. Ovaj rad predstavlja rad na izgradnji AbCoSER-a, prvog korpusa uvredljivog govora na srpskom jeziku. Korpus se sastoji od 6.436 ručno označenih ...
    uvredljivi jezik, govor mržnje, srpski, tviter, leksikon, korpus
    ... threaten out of anonymity ...”); 2. Hate speech (HS), if a tweet contains an attack, disparagement, or promotion of hatred towards a group of people or members of that group on the basis of race, ethnicity, nationality, gender, religion, political orientation, sexual orientation (e.g. “@USER Što se mene ...
    ... pandemic. A system that would be able to detect such texts could help in making the Internet and social media a better and more respectful virtual space. Research and commercial application in this area were so far focused mainly on the English language. This paper presents the work on building AbCoSER ...
    ... dictionary usage examples, we have used a weighted score derived from lexical, word-based and other features (e.g., sentence length, number of all no space chars, digits, weird chars, commas, full 9 https://www.w3.org/TR/turtle/ https://www.w3.org/TR/turtle/ D. Jokić, R. Stanković, C. Krstev, and B ...

  • Geotechnical conditions of “Debelo brdo” tunnel construction on the highway E-80: Nis-Merdare-Pristina (“Peace Highway”)

    Dragoslav Rakić, Irena Basarić Ikodinović, Radojica Lapčević, Dragan Lukić (2024)
    The construction of the highway E-80 has begun in Serbia, which will represent the traffic hub of the Western Balkans and will be part of the main regional transport network of Southeast Europe. Its total length through Serbia is 77 km, and one part of the route is designed through a typical plain terrain, while a larger part of the route passes through hilly terrain. The construction of the tunnel “Debelo brdo” is planned partly in an open cut ...
    „Debelo brdo“ tunnel, temporary slopes, open cut excavation, tunnel excavation, piles

  • The Potential of Biomarkers to Distinguish Lower and Middle Miocene Lignites from the Coal-Mining District of Lusatia

    I. Kojic, J. Kus, D. Zivotic, K. Stojanovic (2021)
    ... lignites, simonellite or retene are the most abundant. Aromatic hopanoids are represented by series of orphan aromatic hopanoids (bearing an ethyl group at C-21), with one to four aromatic rings. The presence of diterpenoids (Di) and non-hopanoid triterpenoids (Tri) in relatively high concentrations ...

  • Actual contamination of the Danube and Sava rivers at Belgrade (2013)

    Milan Antonijević, Marija Arsović, Josef Cáslavský, Vesna Cvetković, Predrag Dabić, Mladen Franko, Gordana Ilić, Milena Ivanovic, Nevena Ivanović, Milica Kosovac, Dragana Medić, Slobodan Najdanović, Milica Nikolić, Jovana Novaković, Tatjana Radovanović, Djurdjina Ranić, Bojan Šajatović, Gorica Špijunović, Ivana Stankov, Jelena Tošović, Polonca Trebse, Olivera Vasiljević, Jan Schwarzbauer (2014)
    rečni sistemi, stanje zagađenja, organski zagađivači, teški metali, skrining analize, non-target screening
    ... Rivers are presented in Table S-III. They are grouped according to their technical application, unless they occur naturally in the envi- ronment (group: Natural products). Abbreviations are given for certain com- pounds. The majority of the identified contaminants were of anthropogenic origin and ...
    ... acts as a UV-protector.26 It was identified in small quantities in all samples. Selected personal care products are presented in Fig. 2. A further group of specific contaminants comprises the technical additives. [2,2,4-Trimethyl-3-(2-methylpropanoyloxy)pentyl]-2-methylpropanoate (TXIB) is added as ...
    ... Fig. 2. Fig. 2. Chemical structures of selected compounds identified in the waters of the Danube and Sava Rivers. A very well known group of water pollutants are pesticides. Acetochlor (2-chloro-N-(ethoxymethyl)-N-(2-ethyl-6-methylphenyl)-acetamide) is a consti- tuent of a variety of ...

  • Understanding the effect of synthesis and sintering temperature on the functional properties of barium titanate/cobalt ferrite composites

    Marija Šuljagić, Aleksandar Kremenović, Ivan Petronijević, Adis Džunuzović, Miljana Mirković, Vladimir Pavlović, Ljubica Anđelković (2023)
    To investigate the effect of synthesis procedure and sintering temperature on the functional properties of perovskite/spinel ceramics, BaTiO3/CoFe2O4 composites were prepared by thermal decomposition, coprecipitation, and microemulsion method, and sintered at 1150°C and 1300°C. The phase composition and morphology of as-prepared powders as well as sintered ceramics were thoroughly examined by X-ray powder diffraction (XRPD) and scanning electron microscopy (SEM) coupled with electron dispersive spectroscopy (EDS). The dielectric and ferroelectric measurements were performed in detail. Generally, the ...
    Perovskite/spinel ceramics, Multiferroic, Sintering, Influence of synthesis method

  • Hypogene speleogenesis related to porphyry magmatic intrusions and its influence on subsequent karst evolution in the Peruvian high Andes

    Alexander Klimchouk, David Evans, Sasa Milanovic, Cristian Bittencourt, Mauro Sanchez, F. Carlos Aguirre (2022)
    Earth-Surface Processes

  • Razvoj ARCGIS geobaze površinskog kopa korišćenjem UML CASE alata

    Aleksandra Tomašević, Ljiljana Kolonja, Ivan Obradović, Ranka Stanković, Olivera Kitanović (2012)
    ... attributes (data describing a geographic entity numerically or textually), geometry (data defining the shape and size of an entity and its position in space) and topology (data defining relations between different geographic entities). Consequently, there are three basic groups of data in a GIS, namely: ...
    ... objects of their own, but they have attributes, which are inherited by their subclasses. The essential purpose of abstract classes is precisely to group attributes of their subclasses. Thus the class Busotine inherits the attributes, relations and operations from all three aforementioned classes. ...
    ... upravljanje kvalitetom uglja, Međunarodni simpozijum ENERGETSKO RUDARSTVO 2010, 08 - 11. September 2010., Banja Junaković, Apatin, Srbijaa. [6] Link Group. [2011] [Online] http://www.link-elearning.com/dlmaterijali/materijali// UML/SadrzajNJpdf/ UML_01.pdf. [7] Naiburg, J. E., Maksimchuk, A. R., [2002]: ...

  • Prvi nalazi repatih vodozemaca (Urodela) u pleistocenskoj pećinskoj fauni Srbije; još jedna kockica u slagalici

    Dragana Đurić, Katarina Bogićević, Draženko Nenadić, Mihajlo Jovanović, Aleksandra Savković (2023)
    Fosilna fauna pleistocenskih pećina odslikava sastav faune njihove okoline. Najčešće se u njima naleze ostaci krupnih sisara ledenog doba koji su je koristili kao stanište. Uz njih česti su i ostaci drugih sitnih kičmenjaka kao što su sitni sisari, ribe, vodozemci, gmizavci i ptice. Ostaci sitnih kičmenjaka u većini slučajeva u pećinu dospevaju kao plen grabljivica (ptice i sisari) ali je manji broj njih pećinu koristio i kao sklonište ili stanište. U proučavanje fluktuacija pleistocenske klime sve češće se ...
    ... plains. Hibernation is usually in groups on the forest floor, hollow trunks, or under rocks. Today, newt Triturus karelinii is recognized as a group that unites several geographically coherent clades distributed from the south-eastern Balkans to the Caspian Sea. It inhabits mixed forests as well ...
    ... of phalanges of an unidentified tailed amphibian, there is a possibility that the cave at some point served as a hibernation place for a smaller group of these amphibians. Another possibility is that they were brought into the cave ncar a watercourse. Unfortunately, this cannot be verified on the ...

  • Multi-Criteria Approach for Selecting Optimal Dozer Type in Open-Cast Coal Mining

    Ivan Janković, Stevan Đenadić , Dragan Ignjatović , Predrag Jovančić , Tomislav Šubaranović, Ivica Ristović (2019)
    Analitički hijererhijski proces (AHP), dozeri, eksploatacija uglja, površinski kopovi
    ... age type. Taking into account the engine power (EP), the analysed dozers belonged to the group of strong dozers in the range of the 190–300 kW class, and according to the nominal towing force (TF) to the group of heavy dozers 250–350 kN. In order to evaluate the priority, the range of the class for ...
    ... for each alternative related to the mentioned sub-criteria. 3.5. Results of Tehnical Parameters (TP) The most significant sub-criterion in the group of technical parameters is towing force, followed by engine power, type of undercarriage, and finally (as the least important parameter) the transmission ...
    ... s for each alternative related to the mentioned sub-criteria. 3.5. Results of Tehnical Parameters (TP) The most significant sub-criterion in the group of technical parameters is towing force, followed by engine power, type of undercarriage, and finally (as the least important parameter) the transmission ...

  • A tool for identifying the criticality in the disordered systems with metastable dynamics

    Svetislav Mijatović, Dragutin Jovković, Sanja Janićević, Stefan Graovac, Đorđe Spasojević (2021)
    Физика кондензоване материје

  • 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, Pyrophyllite

  • Project REASONING: Characterization and technological procedures for recycling and reusing of the rudnik mine flotation tailings

    Vesna Cvetkov, Vladimir Simić, Stefan Petrović, Filip Arnaut, Milena Kostović, Dragan Radulović, Jovica Stojanović, Vladimir Jovanović, Dejan Todorović, Nina Nikolić, Jelena Senćanski, Grozdanka Bogdanović, Dragana Marilović (2024)

  • The number of unimodular roots of some reciprocal polynomials

    Dragan Stankov (2020)
    We introduce a sequence P2n of monic reciprocal polynomials with integer coefficients having the central coefficients fixed. We prove that the ratio between number of nonunimodular roots of P2n and its degree d has a limit when d tends to infinity. We present an algorithm for calculation the limit and a numerical method for its approximation. If P2n is the sum of a fixed number of monomials we determine the central coefficients such that the ratio has the minimal limit. ...
    Algebraic integer, the house of algebraic integer, maximal modulus, reciprocal polynomial, primitive polynomial, Schinzel-Zassenhaus conjecture, Mahler measure, method of least squares, cyclotomic polynomials

  • Damage quantification of built stone on Dark Gate (Belgrade, Serbia): sample of damage index application for decay rate evaluation

    Maja Franković, Nevenka Novaković, Vesna Matović (2015)
    The Dark Gate is the monument of culture, part of the cultural and historical complex of the Belgrade Fortress. It is constructed of limestone blocks that after 270 years of exposure to environmental conditions and different anthropogenic influences show wide ranges of decay forms. During 2007, detail registration of all built limestone microfacies and weathering forms was done using tools of monument mapping. A correlation scheme ‘‘intensity– damage category’’ was made according to the type, intensity, and distribution of ...
    Krečnjak, mapiranje, Indeks raspadanja, brzina raspadanja, progresija
    ... countries and hardly cost-effective for more “commonplace” built heritage. A comprehensive monument mapping method devel- oped by the working group 'Natural stones and weathering"/ Aachen University of Technology (Fitzner et al. 1995, 1997a, b) is cost-effective and non-destructive procedure ...
    ... forms and intensities for the built stone blocks in the Dark Gate in correlation to damage category Environ Earth Sci (2015) 73:6181–6193 Group Loss of stone material Discoloration/deposits Detachment Fissures/deformation Main weathering forms Damage category || 2 3 4 5 Surface ...
    ... Fliigel 2004) Weathering mapping was carried out using the interna- tionally accepted classification scheme developed by the Aachen working group “Natural Stones and Weathering?” (Fitzner et al. 1995) in scientific literature ' known as Fitzne's model mapping. The standard classification ...

  • Callovian (Middle Jurassic) Sphriganaria (Brachiopoda) from the Jordan Valley (Middle East)

    Howard R. Feldman, Barbara V. Radulović, Fayez Ahmad (2023)
    Brachiopods, Middle Jurassic, Sphriganaria, shell microstructure, Ethiopian Province

  • The interaction of organoselenium trans-palladium(II) complexes toward small-biomolecules and CT-DNA

    Vera M. Divac, Aleksandar Mijatović, Marina D. Kostić, Jovana Bogojeski (2017)
    Serija organoselenijum trans-paladijum(II) kompleksa 1 (bis(2-(fenilselanilmetil)oksolan)dihloropaladijum(II)), 2 (bis(2-(fenilselanilmetil)oksan)dihloropaladijum(II)) i 3 (bis(2) ,2-dimetil-3-(fenilselanil)oksan)dihloropaladijum(II)) su korišćeni za ispitivanje reaktivnosti ovog specifičnog tipa kompleksa prema različitim bio-molekulima. Ovaj sistem je od posebnog interesa jer se jako malo zna o supstitucionim reakcijam organoselenijum paladijum(II) kompleksa sa trans konfiguracijom. Zamena koordinovanog hlorida sa serijom malih bio-molekula (l-Met, l-His, l-Cis, GSH i 5′-GMP) proučavana je pod uslovima pseudo-prvog reda kao funkcija koncentracije nukleofila i temperature korišćenjem tehnika zaustavljenog toka. Rezultati za proučavane komplekse ukazuju da ...
    Pd(II), Selen, Substitucija, Kinetika, Mehanizam

  • Sitni, ali bitni: uloga sitnih sisara, herpetofaune i mekušaca u rekonstrukciji pleistocenskih paleosredina

    Katarina Bogićević, Draženko Nenadić, Dragana Đurić, Mihajlo Jovanović, Aleksandra Savković (2023)
    Fosilni ostaci životinja i biljaka imaju važnu ulogu u rekonstrukciji pleistocenskih paleosredina. U ovom radu opisan je značaj tri grupe životinja: sitnih sisara, herpetofaune I mekušaca. Mada je za rekonstrukciju važan sastav čitave asocijacije, nalasci pojedinih vrsta mogu biti dovoljno indikativni da otkriju tip staništa ili klimatske uslove. Posebnu teškoću pri rekonstrukciji paleosredina u Srbiji predstavlja činjenica da klimatske promene na Balkanskom poluostrvu nisu bile tako oštre kao u srednjoj i zapadnoj Evropi, pa ne postoji drastična razlika u ...
    ... type reconstruction is the method of ecological groups. For each species, it is determined in which group of habitats it most often lives today, and then the percentage representation of each group in the entire fauna is calculated. One of the variants is the TH- index method, where the affinity ...

  • Is the Sava-Vardar zone a remnant of an Upper Cretaceous ocen? Pro et contra

    Vladica Cvetković, Dejan Prelević, Ana Mladenović (2024)
    Neotethys, ocean closure, subduction
    ... of them world- scale, porphyry Cu and epithermal Au-Cu ore deposits. These features are commonly found in modern subduction environments. Both group of statements corroborate the hypothesis that after a major convergence and obduction of Balkan ophiolites in the latest Jurassic, a Neotethyan ...