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Упит dcterms_subject_txt:surface functional groups

277 items

  • 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

  • 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
    ... specific surface areas. Whereas the influence of adsorbed water and oxygen on the sum of surface functional groups is minor for most of the chars, about 30% ofthe O1s frac- tion is due to HSO and O, for AC1. Therefore, the corrected value for the total O1s fraction due to surface functional groups ...
    ... types of CO functional groups obtained by C1s and O1s are in fair agree- ment. The ratio of C-O and C = O from O15s, denoted as Ro:s(CO) and the ratio of C-O groups PLOS ONE | hitps://doi.org/10.1371/journal.pone.0277365 November 17, 2022 16/38 PLOS ONE Surface functional groups and degree of ...
    ... oxygen functional groups at the surface of chars, but the results may be influenced by sample preparation and have a relatively large error. Unfortunately, a discrimination of alcohols and phenols and their derivatives (esters, ethers) is not possible by XPS. Since all those functional groups exhibit ...

  • 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 ...
    ... 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 determinated by Boehm titration in two ...
    ... 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 J. Zlatanovi¢ ...

  • Production information system of the Pljevlja coal mine

    Božo Kolonja, Ranka Stanković, Filip Vuković (2018)

  • The subthermal potential of karstic groundwater of Kučaj–Beljanica region in Serbia estimated by the multivariate analysis

    Ljiljana Vasić, Dragana Ž. Živojinovic, Vladana Rajaković-Ognjanović, Huang Fen, Cao Jianhua (2021)
    Earth-Surface Processes, Geology, Pollution, Soil Science, Water Science and Technology, Environmental Chemistry, Global and Planetary Change

  • Photocatalytic Activity of the V2O5 Catalyst toward Selected Pharmaceuticals and Their Mixture: Influence of the Molecular Structure on the Efficiency of the Process

    Sanja J. Armaković, Aleksandra Jovanoski Kostić, Andrijana Bilić, Maria M. Savanović, Nataša Tomić, Aleksandar Kremenović, Maja Šćepanović, Mirjana Grujić-Brojčin, Jovana Ćirković, Stevan Armaković (2023)
    Due to the inability of conventional wastewater treatment procedures to remove organic pharmaceutical pollutants, active pharmaceutical components remain in wastewater and even reach tap water. In terms of pharmaceutical pollutants, the scientific community focuses on -blockers due to their extensive (over)usage and moderately high solubility. In this study, the photocatalytic activity of V2O5 was investigated through the degradation of nadolol (NAD), pindolol (PIN), metoprolol (MET), and their mixture under ultraviolet (UV) irradiation in water. For the preparation of V2O5, facile ...
    DFT analysis, metoprolol, nadolol, nanomaterial characterization, photocatalysis, pindolol, β-blocker
    ... Molecules 2023, 28, 655 3of18 dation rate is determined by the nature of substituents on aromatic rings [25]. For example, Fu et al. noted that surface OH groups play a vital role in increasing the degradation rate of nitrobenzene and methylene blue after introducing, AlyOx particles. The structural ...
    ... 1200-1211. [CrossRef] Becke, A. Density-functional thermochemistry. III. The role of exact exchange. J. Chem. Phys. 1993, 98, 5648–5652. [CrossRef] Lee, C.; Yang, W.; Parr, R. Development of the Colle-Salvetti correlation-energy formula into a functional of the electron density. Phys. Rev. B 1988 ...
    ... Friesner, R.A. Pseudospectral implementations of long-range corrected density functional theory. J. Comput. Chem. 2021, 42, 2089-2102. [CrossRef] Yanai, T.; Tew, D.; Handy, N. A new hybrid exchange-correlation functional using, the Coulomb-attenuating, method (CAM- B3LYP). Chem. Phys. Lett. 2004 ...

  • Development of the Availability Concept by Using Fuzzy Theory with AHP Correction, a Case Study: Bulldozers in the Open-Pit Lignite Mine

    Stevan Đenadić, Dragan Ignjatović, Miloš Tanasijević, Uglješa Bugarić, Ivan Janković, Tomislav Šubaranović (2019)
    Availability is one of the most used terms in maintainability engineering. This concept is used to denote: The quality of service of an engineering system, i.e., machines, weak points’ analysis, asset management, as well as making decisions in the process of life cycle management. Availability is an overall indicator and contains partial indicators that are oriented towards reliability, maintenance, and logistical support. Availability presents a variable value and changes in time and space. Usually, availability is shown as the ...
    raspoloživost, fazi teorija, AHP višekriterijumska analiza, eksperska ocena, buldozer
    ... e of the maintenance function. Functional safety is a common term used to describe availability and the factors that affect it: Reliability, convenience of maintenance, and maintenance support level. The term availability is used to denote the degree of functional safety. Availability is expressed ...
    ... convenience of the maintenance function. Functional safety is a common term used to describe availability and the factors that affect it: Reliability, convenience of maintenance, and maintenance support level. The term availability is used to denote the degree of functional safety. Availability is expressed ...
    ... expressed in quantitative indicators, and as such, is a measure of functional safety, and thus of the quality of service. Monitoring and availability analysis are significant because of the known fact that the machine must, above all, be available for operation, in order to realize other operating performance ...

  • Geochemical characterization of sediments from the archaeological site Vinča – Belo Brdo, Serbia

    Gorica Veselinović, Dragana Životić, Kristina Penezić, Milica Kašanin-Grubin, Nevenka Mijatović, Jovana Malbašić, Aleksandra Šajnović (2020)
    Earth-Surface Processes

  • Functional corerelations between efficiency indicators of investments

    Branislav Marić, Jelena Ćirić, Mitrović Vladimir, Mihajlo Rovčanin (2011)

  • Effectiveness Analysis of Different Bucket-wheel Excavators

    Stevan Đenadić, Predrag Jovančić, Dragan Ignjatović, Miloš Tanasijević, Filip Miletić (2021)
    Coal production in open-pit lignite mines in the Republic of Serbia is performed with continuous work systems. In addition to coal production, the same systems are used for the exploitation of large quantities of overburden. According to the reliability concept, continuous systems are in linear connection. If the failure occurs in one part of the system, that will produce a downtime of the entire system. The initial and most important factor of continuous systems is the bucket-wheel excavator. It ...
    bucket-wheel excavator, open-pit coal mine, mining, multi-criteria decision methods

  • 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

  • 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

  • Flyrock induced by blasting in surface mining

    Milanka Negovanović, Lazar Kričak, Snežana Ignjatović, Stefan Milanović, Jovan Marković, Nikola Simić, Rade Šarac (2022)
    Miniranje predstavlja i dalje najefikasniji i najjeftiniji način eksploatacije velikih količina čvrstih mineralnih sirovina na površinskim kopovima. Energija eksplozije se koristi za fragmentaciju čvrste stenske mase do zahtevane granulacije. Pored pozitivnih efekata miniranja, postoje i određeni neželjeni efekti svakog procesa miniranja koji se mogu javiti, a to su: potresi tla, razletanje komada stene, vazdušni udari, otrovni i zagušljivi gasovi i prašina. Razletanje komada stene je nekontrolisano izbacivanje fragmenata odminirane stenske mase i predstavlja jedan od glavnih izvora materijalne štete ...
    razletanje, bušenje, miniranje, površinska eksploatacija, bezbednost, nesreća

  • Towards Sustainable Management of Transboundary Hungarian-Serbian Aquifer

    Zoran Stevanović, Peter Kozák, Milojko Lazić, Janos Szanyi, Dušan Polomčić, Balazs Kovács, Jozsef Török, Saša Milanović, Bojan Hajdin, Petar Papić (2011)
    ... centralize the waterworks at municipal and regional levels (incorporate small viliage waterworks into mr,rnicipal ones); . keep existing sources functional as an integral part offuture water supply systems; 4.9 Towards Sustainable Management of Transboundary Hungarian-serbian nqu6r, lul 160000 140000 ...
    ... system of Hungary-Serbia was preliminary separated into two parts: one large GW body in Serbia named CS-DU 10, and five in Hungary (P.1. and P.2. groups). The totai area is assumed to cover around 27 0OA1
    ... 11'C and rainfall of 575 mm per year. The whole hydrographic network belongs to the river basin of the Biack Sea. It is assumed that about 99% of surface waters are water flows of a transitory nature, while only about 17o comes from rainfall within the region. The major rivers are the Danube and the ...

  • Parameter determination of soil oscillation law using quotient of the relative growth increments of oscillation velocity and reduced distances at “Nepričava“ open pit mine

    Suzana Lutovac, Sanja Bajić, Marina Ravilić, Radmila Gaćina (2015)
    ... criterion, for the evaluation of convenience of the obtained functional correlation, the following relations are valid: - if it is max 3S  , the obtained functional correlation is rejected as unfavourable; - if it is max 3S  , the functional correlation is accepted as a good one. 4. REVIEW OF ...
    ... there is max1 13S  , supposed functional relationship is accepted as a good one. For model 2: 2 0.7782  - there is a strong correlation between R and v, given in the formula (14). max 2 2 20.5606; 0.2228; 3 0.6683S S    max 2 23S  , supposed functional relationship is accepted as ...
    ... highly strong correlation. The same is valid for the absolute value of linear correlation coefficient r. As a convenience measure of the obtained functional relationship for the given experimental data, the criterion "3S" was also used (Vukadinović, 1970). This criterion uses squares of differences ...

  • Some models for determination of parameters of the soil oscillation law during blasting operations

    Suzana Lutovac, Dragan Medenica, Branko Gluščević, Rade Tokalić, Čedomir Beljić (2018)
    ... the evaluation of convenience of the obtained functional correlation, the following relations are valid: Energies 2016, 9, 617 7 of 15 ‚ if |εmax| ě 3S, the obtained functional correlation is rejected as unfavorable; and ‚ if |εmax| < 3S, the functional correlation is accepted as a good one. 4. M ...
    ... 1776. As εmax1 < 3S1, the supposed functional relationship is accepted as a good one. ‚ For model 2: ρ2 = 0.9893 (there is a strong correlation between R and v, given in Equation (29)). εmax2 = 0.1147, S2 = 0.0550, 3S2 = 0.1650. εmax2 < 3S2 (the supposed functional relationship is accepted as a good ...
    ... 1656. εmax1< 3S1, the (the supposed functional relationship is accepted as a good one). ‚ For model 2: ρ2 = 0.9852 (there is a strong correlation between R and v, given in Equation (32)). εmax2 = 0.1541, S2 = 0.0535, 3S2 = 0.1606. εmax2 < 3S2 (the supposed functional relationship is accepted as a good ...

  • Determination of Mechanical Properties of Altered Dacite by Laboratory Methods

    Veljko Rupar, Vladimir Čebašek, Vladimir Milisavljević, Dejan Stevanović, Nikola Živanović (2021)
    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 ...
    Geology, Geotechnical Engineering, Engineering Geology
    ... 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 UCS of the rock material, and mi) with an increase in the participation ...
    ... 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 UCS of the rock material, and m;) with an increase in the participation ...
    ... procedure, monolithic rock material (100% D and 100% AD) specimens and discs of rock material were prepared. Discs of rock material were used to form groups of composite specimens that contained 10%, 30%, 50%, and 70% volumetric participation of weaker material (altered dacite) (Figure 4). It is essential ...

  • The optimization of auxiliary machinery in open-cast lignite mines: a case study of bulldozers

    Dragan Ignjatović, Predrag Jovančić, Stevan Đenadić, Ivan Janković, Ivica Ristović (2019)
    One of the most important prerequisites for the successful operation of the open-cast lignite mine is to carry out all the auxiliary works timely with the necessary quality. The most important and most commonly used auxiliary machines are bulldozers. Engaging time of bulldozers use is in direct relation with the coefficients of the time and capacity utilization of the continuous system for the excavation of coal and tailings, which indicates their importance. More than 100 bulldozers have been hired ...
    open-cast coal mine, auxiliary works, bulldozers, optimization, availability
    ... during which the mechanization is in functional condition, meaning it is used [2, 5]. Life cycle of a machine, facility or any other technical system has a complex structure, and it encompasses several distinctive but interrelated and timely adjusted groups of activities. Technical system is used ...

  • Structural dissymmetrization of optically anisotropic Grs64±1Adr36±1Sps2 grandite from Meka Presedla (Kopaonik Mt., Serbia)

    Pavle Tančić, Aleksandar Kremenović, Predrag Vulić (2019)
    In this paper, grandite core with Grs64±1Adr36±1Sps2composition was crystallographically studied. This core represents zone A of the macroscopically visiblefive A–E zones of the optically anisotropic Grs58–64 Adr36–42Sps2 grandite. The applied procedure includes the detailed analysis of the powder diffraction patterns, and the Rietveld refinements of the crystal structures in a series of 18 space groups and two mixtures, which were followed by the comparative analysis of the R-values, site occupancy factors, and the bond lengths and angles. Synthesis of all ...
    grandite, XRPD, crystal structure, structural dissymmetrization

  • Preparation of Multimedia Document “YU Rock Scene”

    Milena Obradović, Aleksandra Arsenijević, Mihailo Škorić (2017)
    SUMMARY: This study will present the preparation process of a multimedia document entitled YU ROCK SCENE in which participants were senior students of undergraduate studies of the Department of Library and Information Science at the University of Belgrade Faculty of Philology during the academic year 2014/2015, as a part of the subject Multimedia Documents. This study gives an overview of the historical development of rock and roll in the territory of the former Yugoslavia, rock scene in Yugoslav republics, ...
    multimedia document, library science, information science, rock and roll, music, Yugoslavia
    ... and Rambo Amadeus. Groups primarily influenced by the New Wave appeared on the big Belgrade rock scene in the early 1980s. These groups included Idoli, Šarlo akrobata, Električni orgazam, Ekatarina Velika, Disciplina kičme, Partibrejkers and U Škripcu. The following rock groups then appeared: Piloti ...
    ... culture, which gave birth to large rock groups include: Nǐs, Čačak, Kragujevac, Novi Sad, and several smaller towns, such as Bečej (town in which Eva Braun originated) and which made history of the Former Yugoslavia with one or two bands. Important groups originated in Nǐs – Galija, Kerber and Dobri ...
    ... there. During that time, 84 rock and roll groups were established in Čačak, and most of them originated from the Cultural Artistic Society Abrašević. The first and the most popular group in Čačak in the 1960s was Bele vǐsnje, and the following new groups appeared after them: Zvečarke, Crne mambe ...