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Упит dcterms_subject_txt:carbon and oxygen isotopes

2344 items

  • The analysis of the geothermal energy capacity for power generation in Serbia

    Jana Stojković, Goran Marinković, Petar Papić, Mihailo Milivojević, Maja Todorović, Marina Ćuk (2013)
    Renewable Energy, Sustainability and the Environment
    ... Fundamental theory of geothermometers Silicon is second highest element (first is oxygen) in the Earth's crust. It is a metalloid, under carbon in the Periodic table, between aluminum and phosphorus, having both metal and non-metal properties. It is a very important element in geothermometry, because ...
    ... of this dependence (van't Hoff equation). Conventional geothermometers are based on silicon (quartz, chalcedony, and amorphous silica), cations (Na-K, Na-K-Ca, Na-K-Mg, etc.) and isotopes. Temperature equation for each geothermometer includes a specific equilibrium constant for the given mineral-water ...
    ... of this dependence (van't Hoff equation). Conventional geothermometers are based on silicon (quartz, chalcedony, and amorphous silica), cations (Na-K, Na-K-Ca, Na-K-Mg, etc.) and isotopes. Temperature equation for each geothermometer includes a specific equilibrium constant for the given mineral-water ...

  • Polycyclic aromatic hydrocarbons, sulfur- and oxygen heterocycles released by pyrolysis of coal from Bogovina East field, Serbia

    Mitrović Danica, Đoković Nataša, Vuković Nikola, Životić Dragana, Stojanović Ksenija (2014)

  • Low-temperature phase transition and magnetic properties of K3YbSi2O7

    Predrag Dabić, Volker Kahlenberg, Biljana Krüger, Marko Rodić, Sabina Kovač, Jovan Blanuša, Zvonko Jagličić, Ljiljana Karanović, Václav Petříček, Aleksandar Kremenović (2021)
    alkalni silikati elemenata retkih zemalja, fazni prelazi, magnetne karakteristike, razdvajanje kristalnog polja, silikati lantanica
    ... (4) A and two oxygen atoms at Yb—-O2 distances of 2.222 (6) A. The average Yb—O distance, (2.2153 A), is almost identical to the value of 2.220 (2) A found in the hexagonal 6-K3;YbSi,O7 polymorph. Both O1 and O2 oxygen atoms are further linked to one silicon and four potassium atoms (three K1 and one K2) ...
    ... distances of 2.212 (4) Å and two oxygen atoms at Yb–O2 distances of 2.222 (6) Å. The average Yb—O distance, h2.2153 Åi, is almost identical to the value of 2.220 (2) Å found in the hexagonal �-K3YbSi2O7 polymorph. Both O1 and O2 oxygen atoms are further linked to one silicon and four potassium atoms ...
    ... the boundary between adjacent octahedral and soro- silicate layers, oxygen sheets with 3.6.3.6 meshes formed by terminal nonbridging O atoms can be identified [Figs. 1(a) and 1(b)]. These common O atoms form a pseudo-kagome pattern composed of triangles and hexagons (O’Keeffe & Hyde, 1996). Unlike ...

  • Review: Methodological approaches and research techniques for addressing construction and remediation problems in karst reservoirs

    Saša Milanović, Ljiljana Vasić (2021)
    Earth and Planetary Sciences (miscellaneous), Water Science and Technology

  • A comparative study of the molecular and isotopic composition of biomarkers in immature oil shale (Aleksinac deposit, Serbia) and its liquid pyrolysis products (open and closed systems)

    Gordana Gajica, Aleksandra Šajnović, Ksenija Stojanović, Jan Schwarzbauer, Aleksandar Kostić, Branimir Jovančićević (2021)
    The molecular and isotopic composition of biomarkers in initial bitumen isolated from immature (0.41% Rr) oil shale samples (Aleksinac deposit) and liquid products obtained by pyrolysis in open (OS) and closed (CS) systems are studied. The influence of pyrolysis type and variations of kerogen type on biomarkers composition and their isotopic signatures in liquid products is determined. The applicability of pyrolysis type, numerous biomarkers and carbon isotopic compositions (δ13C) of n-alkanes in liquid pyrolysates is established. Pyrolysis experiments were ...
    Uljni šejl, Aleksinac, organska supstanca, otvoreni i zatvoreni sistem pirolize, biomarkeri, izotopski sastav ugljjenika

  • Određivanje sadržaja kiselih funkcionalnih grupa na površini biougljeva primenom Boehm-ovih titracija

    Aleksandar D. Krstić, Aleksandar Đ. Lolić, Marija A. Ilić, Aleksandar M. Mijatović, Snežana J. Zlatanović, Zoran P. Nedić, Vesna M. Pavelkić (2015)
    Biougalj se dobija pirolizom iz organskog otpada. Smatra se ,,modifikatorom'' zemljišta i koristi se kao đubrivo i kao rezervoar za skladištenje ugljenika. Kvantifikacija funkcionalih grupa je važna zbog hemijske reaktivnosti biougljeva koji imaju uticaj na svojstva zemljišta. U istraživanju su korišćena 3 uzorka biouglja različitog porekla i jedan referentni, aktivni ugalj. Sadržaj kiselih funkcionalnih grupa je određivan titracijom po Boehm-u na dva načina: uvođenje N2 tokom titracije i tretman sa BaCl2. Optimizovan je način pripreme tri Boehm ova rastvora ...
    ... its fertilizing effect and its potential for carbon storage. Quantification of functional groups is interesting because chemical reactivity of biochar can have effect on soil properties. In this researh different samples of biochar are used and one as referent sample. Oxygen surface ‘groups were ...
    ... uvodenja N2. Da bi se proverila efikasnost ovih metoda, ekstrakti su snimani spektrofotometrijski na talasnoj duzini 250 nm. Determination of oxygen surface groups on biochars using Boehm-titration method Aleksandar D. Krstié, Aleksandar D. Lolié, Marija A. Ii, Aleksandar M, Mijatovic’, ‘SneZana ...
    ... *Faculty of Mining and Geology, University of Belgrade, Djusina 7, Belgrade; **Institute of general and physical chemistry, Studentski trg 12-16, Belgrade; ***Faculty of Physical chemistry, University of Belgrade, Studentski trg 12-16, Belgrade ‘“***Institute of Chemistry, Technology and Metallurgy, Njegoseva ...

  • In situ measurements of Cu isotopes in Cu sulphides

    Lazarov Marina, Horn Ingo, Weyer Stefan, Pačevski Aleksandar (2013)

  • Characterization of biochar surface functional groups

    Marija Ilić, Vesna Pavelkić, Aleksandar Lolić, Branko Leković (2021)
    In this work, biochar originating from paper fibres was examined. Biochar was prepared via pyrolysis method at 550°C. Oxygen-containing functional groups on biochar surface were determined. The surface functional groups of biochar were analysed by Fourier transform infrared spectroscopy. The amount of oxygen-containing functional groups was performed with Boehm titration. The total acidity of biochar was mostly attributed to carboxylic and lactonic groups.
    biochar, surface functional groups, spectroscopy

  • Hydrothermal Synthesized and Alkaline Activated Carbons Prepared from Glucose and Fructose—Detailed Characterization and Testing in Heavy Metals and Methylene Blue Removal

    Sanja Krstić, Milan Kragović, Maja Pagnacco, Vladimir Dodevski, Branka Kaluđerović, Miloš Momčilović, Ivica Ristović, Marija Stojmenović (2018)
    glukoza, fruktoza, аktivni ugalj, hidrotermalni tretman, aktivacija hidroksida, teški metali, metilen plavo
    ... for fructose and LiOH activated samples, while the least pronouncing was obtained for KOH activated samples. That is also confirmed by XRPD and Raman spectrometry and is described in Section 3.1.1. Variation in oxygen and hydrogen contents may be explained with formation of the oxides and releasing of ...
    ... adsorption and removal of different Minerals 2018, 8, 246 8 of 21 pollutants, inorganic or organic. From that reason carbon samples prepared from glucose and fructose and activated by different hydroxides (LiOH, NaOH and KOH) were characterized by adsorption/desorption of N2 at 77 K and results are ...
    ... activated with LiOH. • After treating of carbon samples with KOH, the changing and destroying of their spherical shapes and microspheres were noticed in the case of both glucose and fructose precursors. On the contrary, carbon samples treated with LiOH and NaOH maintained their microspherical structures ...

  • Surface functional groups and degree of carbonization of selected chars from different processes and feedstock

    Marija Ilić, Franz-Hubert Haegel, Aleksandar Lolić, Zoran Nedić, Tomislav Tosti, Ivana Sredović Ignjatović, Andreas Linden, Nicolai D. Jablonowski, Heinrich Hartmann (2022)
    The knowledge ofthe structural and chemical properties of biochars is decisive for their application as technical products. For this reason, methods for the characterization of biochars that are generally applicable and allow quality control are highly desired. Several methods that have shown potential in other studies were used to investigate two activated carbons and seven biochars from different processes and feedstock. The chars were chosen to cover a wide range of chemical composition and structural properties as a hardness ...
    Biougalj, različiti procesi dobijanja, različite sirovine, površinski aktivne grupe, x-ray, FT-IR,XPS
    ... org/10.1371/journal.pone.0277365.t008 carbon and carbon of oxygen functional groups increased in the ground sample of HW1100g indicating that the creation of new surfaces influences the results of XPS. The result of C1s (Table 7) and O1s (Table 8) for C = O and C-O, however, are contradictory indicating ...
    ... activated carbon). All chars excluding activated carbon are termed biochars. They are divided into hydrochars made by hydrothermal carbonization and pyrochars made by pyrolysis or gasification. The paper focusses on the characterization of oxygen containing sur- face functional groups and the state ...
    ... (untreated) and 1166 cm ! (treated) is due to aromatic in-plain CH deformation vibrations [85] and may contain overlapping peaks of oxygen functional groups (few oxygen content here). The bands at 873 (untreated) and 872 (treated), 808 (untreated) and 809 (treated) and 748 cm ”' (treated and untreated) ...

  • Konceptualni model hidrogeotermalnog sistema šire okoline Brusa - geotermalna karakterizacija sistema / Conceptual model of hydrothermal system of Brus area - system geothermal characterization

    Dejan Milenić, Ana Vranješ, Marinko Toljić, Ivana Vasiljević, Natalija Radosavljević, Matija Ognjanović (2024)
    Postavljeni konceptualni model hidrogeotermalnog sistema Brusa sa širom okolinom testiran je primenom različitih hidrohemijskih i izotopskih metoda u cilju njegove verifikacije i karakterizacije. Rezultati su ukazali na atomsfersko poreklo geotermalnih fluida i na razviće primarnih rezervoara u okviru karbonatnih stena. Prvi rezervoar formiran je u okviru krečnjaka gornjotrijakse starosti, dok drugi rezervoar egzistira u okviru trijskaih mermera. Zone prihranjivanja locirane su u zapadnom delu terena. Sistemi gravitacionih raseda kontrolišu kretanje fluida u sistemu, dok proces jonske izmene dominira u ...
    hidrogeotermalni sistem, hidrohemijske i izotopske metode, mladi intruzivi

  • Inhibitory effect of platinum and ruthenium bipyridyl complexes on porcine pancreatic phospholipase A2

    Tina Kamčeva, Jörg Flemmig, Bojana Damnjanović, Jürgen Arnhold, Aleksandar Mijatović, Marijana Petković (2011)
    Fosfolipaza pankreasa A2 (PLA2) igra važnu ulogu u ćelijskoj homeostazi kao iu procesu karcinogeneze. Efekti metalo-lekova koji se koriste kao hemoterapeutici na aktivnost ovog enzima nisu poznati. U ovom radu, interakcija između PLA2 svinjskog pankreasa i dva odabrana kompleksa prelaznih metala — tetrahloro(bipiridin) platine(IV) ([PtCl4(bipi)]) i dihloro (bipiridin) rutenijum(III)hlorida ([RuCl2(bipi)2) ]Cl)—proučavana je. Laserska desorpcija/jonizacija uz pomoć matriksa, vremenska masa spektrometrija (MALDI-TOF MS) i fluorescentna spektroskopija korišćeni su za analizu aktivnosti enzima u odsustvu i prisustvu metalnih kompleksa i za ...
    Metals and Alloys, Biochemistry, Biomaterials, Biophysics, Chemistry (miscellaneous)
    ... five different sample spots and under the same experimental conditions of acquisition. Table 1 Structural and empirical formula with molecular masses of metal complexes. Molecular mass is given for an isotope mixture considering the natural abundance of all isotopes Structural formula Empirical ...
    ... abundance of all isotopes Molecular mass/ Structural formula Empirical formula g mol”! OQ |” N a Cl Ru RuCh(bipy),JCl ‘519.8 aa [RuCh(dipy)2 N ow! oS Cl ( } KO} Cl Pt. [PtCla(bi 493.1 va 4 “Ol 4( ipy)] . Oo methanol) and trifluoroacetic acid (TFA) were purchased from Fluka and Sigma (Taufkirchen ...
    ... possible because of their low intensity and the fact that ruthenium exhibits a broad distribution of isotopes. The original [RuCl2(bipy)2]Cl is apparently converted in the aqueous environment into two different species, one losing all chloride anions, and another replacing them with one more bipy ...

  • The use of biological markers in determination of origin and type of organic matter in the Tisza river sediments

    Snežana Štrbac, Gordana Gajica, Aleksandra Šajnović, Nebojša Vasić, Ksenija Stojanović, Branimir Jovančićević (2013)
    The objective of the study was to determine the origin and type of organic matter (OM) of the Tisza recent sediments along the distance of 153 km through the territory of Serbia. For this purpose group organic-geochemical parameters and biomarker compositions were used. All samples contain approximately same amount of OM, which was deposited under uniform, slightly reducing conditions. Based on the distribution of n-alkanes, the origin and type of OM could not be precisely estimated. However, n-alkane patterns ...
    sediments, Tisza River, organic matter, biomarkers, oil pollutants
    ... TISZA RIVER SEDIMENTS 601 TABLE II. Group organic–geochemical parameters; Corg – total organic carbon content; db – dry basis; HC – hydrocarbons; NSO – polar compounds containing nitrogen, sulphur and oxygen Sample Content of Corg, % db N, %, db S, % db Bitumen, % Saturated HC, % Aromatic HC ...
    ... The Biomarker Guide, Vol. 2: Biomarkers and Isotopes in the Petroleum Exploration and Earth History, Cambridge University Press, Cambridge, 2005, pp. 483–486, 499–500, 483–486, 493, 499, 558, 569, 612 2. B. P. Tissot, D. H. Welte, Petroleum Formation and Occurrence, 2nd Ed., Springer-Ver- lag, Heidelberg ...
    ... dichloro- methane (4:1 volume ratio) and the NSO fractions (polar fraction, which contains nitrogen, sulphur, and oxygen compounds) with mixture of dichloromethane and methanol (1:1 volume ratio). The saturated hydrocarbons were analyzed by gas chromatography–mass spectrometry (GC–MS). A gas chromatograph ...

  • 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
    ... by coordination via oxygen atoms followed by slow isomerization to N3 from the imidazole ring. The reaction with DMSO is the slowest. This was unexpected because DMSO could coordinate via sulfur or oxygen. However, here a very rigid geometry of the nucleophile makes access and bond formation difficult ...
    ... py)Cl]? in 0.1 M NaClO4, 20 mM NaCl at 310 K Kinetics, mechanism, and equilibrium studies of the reactions 1491 123 ‘‘harder’’ than platinum(II) complexes [47]. This clearly explains and supports the bond formation via oxygen atoms rather than via sulfur or nitrogen, as was the case with anti- ...
    ... 1492 A. M. Mijatović et al. 123 1492 A. M. Mijatovié et al. “harder” than platinum(ID) complexes [47]. This clearly explains and supports the bond formation via oxygen atoms rather than via sulfur or nitrogen, as was the case with anti- tumor “soft” platinum complexes. For determination of the values ...

  • Study of the Synergetic Effect of Co-Pyrolysis of Lignite and High-Density Polyethylene Aiming to Improve Utilization of Low-Rank Coal

    Ivan Kojić, Achim Bechtel, Nikoleta Aleksić, Dragana Životić, Snežana Trifunović, Gordana Gajica, Ksenija Stojanović (2021)
    Polimeri i plastika, opšta hemija
    ... pyrolysis comprising S1, S2, S3, Tmax, total organic carbon (TOC), hydrogen index (HI), oxygen index (OI), and production index (PI) are listed in Table 2. As expected, the HI versus OI diagram (Figure 2) clearly indicates kerogen type III for lignite, and very high liquid generation potential for HDPE exceeding ...
    ... hydrogen index (HI) vs. oxygen index (OI) plot. Legend: TOC—total organic carbon. The content of organic carbon (Corg) obtained by elemental analysis is almost identical to the TOC from Rock Eval pyrolysis (Tables 2 and 3). The notable increase of TOC (Corg) in solid residues of lignite/HDPE mixtures in comparison ...
    ... total organic carbon, obtained by elemental analysis; oxygen = 100—(carbon + hydrogen + nitrogen + sulphur + ash); theoretical values are adjusted at two decimal places. Polymers 2021, 13, 759 13 of 25 Table 4. Calculated net calorific values (MJ/kg) of solid residues of lignite and lignite/HDPE mixtures ...

  • Seasonal Variations of the Zapadna Morava River Water Quality

    Nebojša Đ. Pantelić, Jana S. Štrbački, Goran Marković, Jelena B. Popović-Đorđević (2021)
    The water samples collected from four localities of the middle course of the Zapadna Morava River during 2020 were analyzed via the selected physicochemical parameters with the aim to estimate the quality of surface water. According to the results of selected physico-chemical parameters (pH, conductivity, dissolved oxygen, chemical oxygen demand, biochemical oxygen demand), analyzed surface water show a good chemical status, while the values of nutrient content (nitrate, nitrite, ammonium ion, total phosphorus) indicated the poor chemical status especially ...
    water quality, dissolved oxygen, ammonium ion, total phosphorus

  • Human Hemoglobin and Antipsychotics Clozapine, Ziprasidone and Sertindole: Friends or Foes?

    Lena Platanić Arizanović, Nikola Gligorijević, Ilija Cvijetić, Aleksandar Mijatović, Maja Krstić Ristivojević, Simeon Minić, Aleksandra Nikolić Kokić, Čedo Miljević, Milan Nikolić (2023)
    Packed with hemoglobin, an essential protein for oxygen transport, human erythrocytes are a suitable model system for testing the pleiotropic effects of lipophilic drugs. Our study investi gated the interaction between antipsychotic drugs clozapine, ziprasidone, sertindole, and human hemoglobin under simulated physiological conditions. Analysis of protein fluorescence quenching at different temperatures and data obtained from the van’t Hoff diagram and molecular docking indicate that the interactions are static and that the tetrameric human hemoglobin has one binding site for ...
    Inorganic Chemistry, Organic Chemistry, Physical and Theoretical Chemistry, Computer Science Applications, Spectroscopy, Molecular Biology, General Medicine, Catalysis

  • FTIR spectroscopic study оf S-мetolachlor сorption оn inorganic and organically modified montmorillonite from Bogovina

    Lazar Kaluđerović, Zorica Tomić, Jelena Bogosavljević, Ljubomir Životić, Maja Milošević (2021)
    ... Global Challenges Both lone electron pairs on the oxygen of methoxy and ethoxy group are in resonance with the lone pair on nitrogen and the double C=O bond, which delocalizes the charge distribution and reduces the charge density on the carbonyl oxygen (Liu et al., 2000). The second significant change ...
    ... are in the interlayer space and/or oxygen on the surface of the tetrahedral sheet of the montmorillonite. Keywords: adsorption, S-metolachlor, HDTMA, PTMA, infrared spectroscopy INTRODUCTION The high solubility of some herbicides negatively affects their efficiency and therefore causes serious ...
    ... between n electrons of the phenyl ring and n celectrons of the oxygen in the tetrahedral layer of the montmorillonite (Majdan et al., 2009). Also, the band at 1300 cm"! disappeared, which is due to a strong interaction between positively charged nitrogen and negatively charged montmorillonite sites ...

  • Hydrochemistry of groundwater contaminated by petroleum hydrocarbons: the impact of biodegradation (Vitanovac, Serbia)

    Nenad Marić, Jana Štrbački, Sanja Mrazovac Kurilić, Vladimir P. Beškoski, Zoran Nikić, Snežana Ignjatović, Jovana Malbašić (2020)
    Aquifer contamination by petroleum hydrocarbons leads to measurable changes of groundwater hydrochemistry, primarily due to the microbiological activity. This study analyzes this phenomenon at an historical kerosene-contaminated site in Vitanovac (central Serbia). Due to the long-term hydrocarbon contamination and exposure to aerobic and anaerobic biodegradation mechanisms, the lowest concentrations of O2, NO3−, and SO42− (electron acceptors) and the highest concentrations of Mn and Fe (products of microbial metabolic activity) overlap. The terminal redox-accepting processes in groundwater ranged from oxygen ...
    podzemne vode, hidrohemija, zagađenje, naftni ugljovodonici, biodegradacija

  • Determination of oxygen surface groups on biochars using Boehm-titration method

    Krstić D. Aleksandar, Lolić Đ. Aleksandar, Ilić Marija, Mijatović Aleksandar, Zlatanović J. Snežana, Nedić P. Zoran, Pavelkić M. Vesna (2015)