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Упит dcterms_subject_txt:quality of service

2843 items

  • The state and perspective of the natural gas sector in Serbia

    Dejan Ivezić, Marija Živković, Dušan Danilović, Aleksandar Madžarević, Miloš Tanasijević (2016)
    The strategy of long-term energy development of Serbia identifies an increase of share of natural gas in final energy consumption as one of the main aims. Serbia has signed a strategic agreement with the Russian Federation on cooperation in the oil and gas sector, within which the project South Stream pipeline is planned to be realized. In addition, the Republic of Serbia has signed the Treaty that establishes the Energy Community and accepted the obligation to implement the Energy ...
    Consumption, natural gas, scenarios of development

  • 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)
    ... I), University of Belgrade Institute of Physics, University of Belgrade Center of Excellence for the Synthesis, Processing and Characterization of Materials for use in Extreme Conditions "CEXTREME LAB” - Institute of Nuclear Sciences "Vinča”, University of Belgrade Faculty of Mechanical Engineering ...
    ... Institute of Nuclear Sciences *Vinča”, University of Belgrade Faculty of Mechanical Engineering, University of Belgrade Center of Excellence for Green Technologies, Institute for Multidisciplinary Research, University of Belgrade Faculty of Technology and Metallurgy, University of Belgrade ...
    ... University of Belgrade Center of Excellence for the Synthesis, Processing and Characterization of Materials for use in Extreme Conditions “ĆCEXTREME LAB” – Institute of Nuclear Sciences “Vinča”, University of Belgrade Faculty of Mechanical Engineering, University of Belgrade Center of Excellence ...

  • Laboratory testing of fly ash

    Miloš Šešlija, Aleksandra Rosić, Nebojša Radović, Milinko Vasić, Mitar Đogo, Milovan Jotić (2016)
    Fly ash is one of the most common waste materials created by burning of coal. It is composed of smaller particles, consisting mainly of aluminosilicate glass, mullite and quartz, which are collected by electrostatic separators (filter) of gaseous products arising from the combustion of coal. This paper presents the pozzolanic properties, mechanical properties, chemical and mineral composition of fly ash obtained in the combustion process in a power plant Nikola Tesla A (PPNT A) with the addition of a ...
    chemical composition, fly ash, mechanical properties, mineral properties, pozzolanic properties, X-ray diffraction
    ... studies at the Laboratory of Crystallography Faculty of Mining - Geology in Belgrade. X-ray diffraction is a non- destructive experimental method based on the usage of the diffraction of X-rays with crystal lattice sized wavelengths. This method is primarily used for quality analysis, due to the fact ...
    ... - the modulus of elasticity. The aim of research is to test the possibility of using the fly ash from PPNT A for making elements of road structures (top and bottom layers of the road). 2 Experimental 2.1 Mineral properties of fly ash Mineral properties of samples of fly ash from thermal ...
    ... the addition of a binder hydrated lime and cement. Tests were performed after 7 and 28 days in a humid environment with different amounts of extra binder: - samples without the addition of binders, - a sample with the addition of 2 % of binder, - a sample with the addition of 4 % of binder, - ...

  • 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
    ... than pyrolysis of lignite of better quality (64.35% of carbon, dry basis, and net calorific value of 25.78 MJ/kg) at 600 ◦C [16]. The yields of liquid and gaseous products of lignite/HDPE co-pyrolysis at 500 ◦C are also higher than the yields of these products obtained by mild liquefaction of lignite (t ...
    ... n to that of crude oils is also noticed at 500 ◦C. The yields of liquid and gaseous products and quality of pyrolytic products obtained by co-pyrolysis of lignite/HDPE mixture are notably improved compared with pyrolysis of lignite alone. On the other hand, data obtained from pyrolysis of HDPE alone ...
    ... n to that of crude oils is also noticed at 500 °C. The yields of liquid and gaseous products and quality of pyrolytic products obtained by co-pyrolysis of lignite/ HDPE mixture are notably improved compared with pyrolysis of lignite alone. On the other hand, data obtained from pyrolysis of HDPE alone ...

  • Geotechnical zoning of the terrain along the first section of E-80 highway in Serbia – SEETO route 7

    Dragoslav Rakić, Zoran Berisavljević, Irena Basarić, Snežana Bogdanović, Jovana Janković (2019)
    Part of E-80 highway that passes through Serbia (from the city of Nis to the administrative border Merdare) is 77 km long. The highway is divided into two sections: the first from Nis to Plocnik (39.4 km long) and the second from Plocnik to the administrative border with Kosovo. The route is designed through a typical plain and hilly terrain in which different geological units are dominant: crystalline schists, neogene sediments of foothills and quaternary sediments in the valley ...
    ... cross-section of Neogene hilly terrain (km: 9.0-12.0) Figure 6. Characteristic engineering geological cross-section of the crystalline schist complex The central part of the highway route is built of crystalline schist complex (Gs, Ga, Gm, M, Q, ) of different quality with variable ...
    ... on of design parameters of seismicity for structures, forming of engineering geological map of limitations. 2 ENGINEERING GEOLOGICAL CONDITIONS IN THE ZONE OF HIGHWAY ROUTE Regional rupture pattern indicates two systems of perpendicular structures that form a block structure of investigated ...
    ... embankments height of 0.5 to 1.5 m (locally, in the case of bridges approaches, embankments of higher heights are designed). The groundwater level is at depth over 5.0 m, and only in the zones of smaller streams is at depth of about 2.0 m. In geotechnical sense, most of the route is estimated ...

  • Application of Lignite Combustion Waste Slag Generated in Heating Plants as a Partial Replacement for Cement. Part II: Physical–Mechanical and Physical–Chemical Characterization of Mortar and Concrete

    Milan Kragović, Nenad Ristić , Jelena Gulicovski, Andrijana Nedeljković, Snežana Pašalić, Ivica Ristović, Marija Stojmenović (2021)
    sagorevanje lignita, otpadna šljaka, zamena cementa, proizvodnja maltera i betona, fizičko-mehanička i fizičko-hemijska karakterizacija
    ... the combustion of lignite was sampled from the landfill of the heating plant located in Valjevo, Serbia. The sampling was performed as it is described elsewhere [16]. Since in the plant there is no planned waste disposal, in order to get a more realistic picture in terms of the quality of waste material ...
    ... in the length of the tested sample, while the shrinkage of cement mortar was expressed as a ratio of variation in length and the initial length of the specimen at the start of testing. The difference in readings represented the variation in length of the tested sample, while shrinkage of the cement mortar ...
    ... results showed that the lack of slag in terms of the content of SiO2, Al2O3, Fe2O3, and unburned carbon, and the loss of ignition, may be overcome by the thermal treatment of the slag prior to use, up to 650 ◦C. Results also showed that other physical– chemical characteristics of slag (crystal, structural ...

  • Environmental Energy Security Indicators as Tools for Environmental Protection

    Aleksandar Madžarević, Dejan Ivezić, Marija Živković , Miloš Tansijević (2019)
    Еколошка прихватљивост је постала незаменљив синтезни показатељ сваке валидне енергетске анализе у последње две-три деценије. Енергетска безбедност је у директној хармонији с еколошком прихватљивошћу кроз многе прописане политичке циљеве, економске користи, правне тековине итд. Индикатори еколошке сигурности представљају један од основних елемената за одређивање енергетске безбедности и снажне алате за усмеравање енергетског сектора ка одрживом развоју. У овом раду, анализа је била концентрисана на показатеље енергетске безбедности у области животне средине који се односе на сектор природног гаса у ...
    енергетска безбедност, еколошки енергетски индикатори, заштита животне средине, еколошка прихватљивост
    ... protection. Energy scenarios of development of natural gas sector based of historical trends and Action plan [5] are used as example of model analysis. These scenarios are than modified in sense of determination of energy security and assessment of the highest level of 2 environmental acc ...
    ... amount of greenhouse gases emitted is standard expressed per tons of CO2eq emitted. CO2eq is a unit based on the global warming potential (GWP) of different greenhouse gases. It measures and expresses the impact of one tons of any other GH gases emitted relative to the impact of one tons of CO2. Moreover ...
    ... gas energy scenario development For the purpose of demonstrating the impact of energy security on environmental protection, through the Indicator of environmental acceptability, the scenario of development of the natural gas sector of the Republic of Serbia [5] will be considered through the model ...

  • Application of the VIKOR Method for Selecting the Purpose of Recultivated Terrain after the End of Coal Mining

    Radmila Gaćina, Sanja Bajić, Bojan Dimitrijević, Tomislav Šubaranović, Čedomir Beljić, Dragoljub Bajić (2024)
    reclamation, coal, sustainable development, multi-criteria decision making, VIKOR method

  • Investigation of quantitative indicators of anisotropy based on longitudinal elastic waves propagation velocities with uncertainty

    Miloš Gligorić, Jelena Majstorović, Suzana Lutovac (2018)
    ... (1996) Assessment of the quality of building stones using signals processing procedures, Quarterly Journal of Engineering Geology and Hydrogeology, 29, pp. 299–308. VASANELLI E. et al. (2015) Ultrasonic pulse velocity for the evaluation of physical and mechanical properties of a highly porous building ...
    ... can thus be applied to assess the quality of the stones, to detect any presence of microscopic fissuring and cracks, to evaluate the material decay and to assess the effectiveness of consolidation products (Esbert, 2007; Favaro et al., 2006; Fort et al., 2013; Jasiehko and Stawiski, 2001; Kahraman ...
    ... same for both approaches of determining the degree of anisotropy. The existence of that high similarity clearly indicates that it is an isotropic medium. During modelling of the anisotropic rock masses, knowing of the quantitative indicators of anisotropy would be of great use for creating reliable ...

  • 3D modeling and monitoring of karst system as a base for its evaluation and utilization: a case study from eastern Serbia

    Saša Milanović, Zoran Stevanović, Ljiljana Vasić, Vesna Ristić-Vakanjac (2013)
    Earth-Surface Processes, Geology, Pollution, Soil Science, Water Science and Technology, Environmental Chemistry, Global and Planetary Change

  • Softverski alati za korišćenje resursa za srpski jezik

    Ivan Obradović, Ranka Stanković (2008)
    ... s in LADL format, none of them of- fered possibilities for management of the content of the dictionaries themselves. Thus a module was developed within WS4LR for the entry, re- view and update of lemmas of simple words and compounds, which supports the specific features of all three solutions (Intex ...
    ... management of dictionaries of simple words IVAN OBRADOVIć, RANKA STANKOVIć 49a The system of morphological dictionaries sup- ports the distribution of the dictionaries, namely enables the distribution of lemmas in several dic- tionaries, such as the dictionary of toponyms or dictionary of proper names ...
    ... May 2008 operates under the auspices of the Faculty of Mathematics of the University of Belgrade and gathers researchers in this field from several Fac- ulties. The most important and the most devel- oped among them is the system of morphological dictionaries of Serbian (SMD). Another highly important ...

  • 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 influence of Al<sup>3+</sup>ion on porcine pepsin activity<i>in vitro</i>

    Vesna M. Pavelkić, Kristina R. Gopcević, Danijela Z. Krstić, Marija A. Ilić (2008)
    The in vitro effect of Al3þ ions in the concentration range 1.7·1026M–8.7·1023M on pepsin activity at pH 2, via kinetic parameters and its electrophoretic mobility was evaluated. Kinetic study demonstrated the existence of an activation effect of Al3þ at pH 2 on pepsin molecule. Kinetic analysis with respect to concentrations of haemoglobin showed that Al3þ ions increase the maximal velocity (Vmax) and kcat values rather than apparent affinity for substrate (KS) implying the non-competitive nature of activation which indicated ...
    Пепсин, алуминијум, кинетика, активација, електрофоретска мобилност
    ... Activation of pepsin by Al * ions; The intercepts on the abscissa of the primary plot of [Hb]/V against reciprocal of activator concentrations provide the values of Aso used to obtain the plots of 1/Aso against vo/V shown in the inset. B, curve 2) contain characteristic bands of haemo- globin ...
    ... enzyme of gastric juice and as the best understood of 215 N -_ this family of proteinases it was used as a model to Asp located at· the centre of the b{ndmg cleft study related enzymes. As all aspartic proteinases between the domains. One of two Asp residues has to pepsin molecule consist of two ...
    ... urk plot of a series of kinetics measurements in a presence of different A! P in vitro ... 1005 Zctivation of bebsin by 4 Kinetic constants obtained from Lineaweaver-Burk plot at variety of different activator concentrations, are presented in Table I. As can be seen, increasing of aluminium ...

  • Conversion of land areas after coal mine closure and reclamation

    Radmila Gaćina, Bojan Dimitrijević, Sanja Bajić (2023)
    Otkopavanje uglja površinski i podzemno praćeno je degradacijom zemljišta, promenom formiranja predela i izmenom flore i faune. Od velikog značaja je razvoj novih naučno utemeljenih pristupa obnovljanje antropogeno poremećenih predela zasnovanih na formiranju rekultivacionih i rudarskih tehnologija. Apsolutno je neophodno obezbediti sveobuhvatno kvalitetno očuvanje zemljišnih i vodnih resursa i odrediti rekultivisano zemljište za novu namenu. U ovom članku je dat pregled najpopularnijih metoda rekultivacije zemljišta i mogućnosti rekultivacije zemljišta nakon završetka rekultivacije i zatvaranja rudnika uglja.
    rekultivacija, melioracija, revitalizacija, otkopavanje uglja, održivi razvoj
    ... on the formation of reclamation and mining technologies. t is absolutely necessary to ensure the comprehensive quality preservation of land and water resources and to designate reclaimed land for a new purpose. This article presents an overview of the ranking most popular methods of land recultivation ...
    ... degraded areas into the productive and/or ecological area of the regions where they are located, which leads to the regeneration of their cconomic potential; improving the quality of the environment; reducing slopes and diminishing the intensity of erosion phenomena and accelerating the vegetation installation ...
    ... natural environment, application of the proper material management — soil, leguminous mixtures, seedlings, etc. optimization of the existing: reclamation methods by introduction of improvements and new solutions to the process, in order to increase quality and yield of the reclaimed land. This paper ...

  • Towards Better Valorisation of Industrial Minerals andRocks in Serbia—Case Study of Industrial Clays

    Vladimir Simić, Dragana Životić, Zoran Miladinović (2021)
    Management, Monitoring, Policy and Law,Nature and Landscape Conservation
    ... those are re- serves of A + B + C1 categories), but continuous exploitation of bentonite in Serbia never existed. The main problems of valorisation of most bentonite deposits are relatively small deposits with layers of bentonite of small thickness, mostly medium or poor quality of raw materials, and ...
    ... evaluation of both the current exploration methodol- 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 ...
    ... nor the minimum number of re- quired tests. We have proven that much more attention should be focused on the complex study of industrial clays on the one hand (origin of certain industrial types of clays, their quality, and possibilities of application) and improvement of exploration process, exploi- ...

  • The Fuzzy–AHP Synthesis Model for Energy Security Assessment of the Serbian Natural Gas Sector

    Aleksandar R. Madžarević, Dejan D. Ivezić, Miloš L. Tanasijević, Marija A. Živković (2020)
    Natural gas is used for the production of almost 20% of total energy today. The natural gas security of the Republic of Serbia is an urgent strategic, political and security issue. Serbia is one of the most vulnerable countries in Southeast Europe, because it only has one supply route. This study is a contribution to efforts to better understand the factors affecting energy security through the implementation of a new methodology based on the fuzzy–AHP synthesis model for measuring ...
    energetska bezbednost, prirodni gas, fazi AHP, AHP višekriterijumska analiza, fazi teorija
    ... level of quality and intensity of scenarios from energy, economic, environmental and social views. The process of compositing fuzzy relationships was done using a “max–min” model of fuzzy composition. One of the key characteristics of the proposed methodology was its attempt to adopt the group of synthetic ...
    ... suppliers determined on the basis of the quality of the government of the Republic of Serbia, as well as 276581 end customers (269380 in regulated supply and 1515 in free market) [71]. The wholesale natural gas market, except for the purchase of gas for the needs of public suppliers, is based on bilateral contracts ...
    ... security of different energy scenarios. Key findings of this methodology can assist in the decision-making process in assessing and choosing quality and effectively direction of energy development. The methodology proposed in the study attempts to analyze and evaluate the energy security situation of the ...

  • Coal homogenization stockyard sizing “Tamnava – Zapad” case study

    Božo Kolonja, Dinko Knežević, Ranka Stanković, Dejan Stevanović, Detlef Trummer (2016)
    ... should be considered in the context of the other components of the Coal Quality Management System, and not separately. COAL QUALITY Regarding coal quality, an important parameter relates to the quality range of the parameter of interest. Most often the parameters of interest are the lower heating ...
    ... the operation of the stacking and reclaiming equipment. The output sequence of property values reflects the quality of the coal after blending. Case study from northern Greece mines show that coal-blending efficiency is a function of the capacity of the stockpile, the number of stockpile layers ...
    ... and then as the sum of all piles. Standard deviation was used to measure success of operation and the required number of layers at the stockyard, while the selected travel speed of the stacker depends on coal quality, the operating rate of the mining machines and the capacity of the stacker. The selected ...

  • Split-Desktop software for the analysis of fragment size distribution of blasted rock mass

    Milanka Negovanović, Lazar Kričak, Stefan Milanović, Jovan Marković, Nikola Simić, Snežana Ignjatović (2023)
    Drobljenje stena je najvažniji pokazatelj u proceni efekata miniranja pri proizvodnom miniranju u površinskoj eksploataciji. Stepen drobljenja stena ima veliki uticaj na efikasnost daljih operacija utovara, transporta, drobljenja i mlevenja. Optimalno drobljenje stena pri proizvodnom miniranju utiče na smanjenje ukupnih troškova proizvodnje. Stoga je pouzdana procena veličine drobljenja odminirane stenske mase veoma važno pitanje, ne samo u operacijama miniranja, već i u rudarskoj proizvodnji. Za predviđanje distribucije veličine komada odminirane stenske mase postoje različiti empirijski modeli. KUZ-RAM model omogućava ...
    Split-Desktop softver, drobljenje stena, miniranje, analiza, digitalna obrada fotografija

  • Evaluation of the effects of wastewater heat pump integration into district heating systems by simulation

    Dejan Ivezić, Marija Živković, Dimitrije Manić, Aleksandar Madžarević, Boban Pavlović, Dušan Danilović (2023)
    The integration of wastewater heat pumps (using purified water) in district heating systems is analyzed in this paper. The simulation procedure is proposed to analyze the impacts of stochasticity of purified water temperature and flow to heat pump integration and operation. The analysis includes calculation of the daily and seasonal coefficient of performance, as well as fossil fuel savings and CO2 emission reduction due to wastewater heat pump use. The proposed procedure is implemented for the case study in ...
    otpadne vode, toplotna pumpa, daljinsko grejanje, simulacija

  • Valorization of non-balanced coal reserves in Serbia for underground coal gasification

    David Petrović, Lazar Kričak, Milanka Negovanović, Stefan Milanović, Jovan Marković, Nikola Simić, Ljubisav Stamenić (2019)
    In the name of a better and safer energy future, it is our responsibility to focus our knowledge and activities to save on imported liquid and gas fossil fuels, as well as coal on which energy security of Serbia is based. The rationalization in the use of available energy resources certainly positively affects economy and the environment of a country. This paper indicates motivations for the application of the underground coal gasification process, as well as surface gasification for ...
    ugalj, gasifikacija, zaštita životne sredine, skladištenje, solarna
    ... The final quality of gas — syngas depends on many influential parameters related to drilling options, geological characteristics and coal quality. Technological process of UCG The technological process of UCG involves the preparation of a coal gasification layer and consists of drilling vertical ...
    ... forecast of changes in the water quality of the aquifer. Measures of preventive character are those that can prevent the possibility of con- tamination of groundwater. In addition to these groundwater protection measures, localization and liquidation measures are also applied. Those along with preventive ...
    ... dissemination. The aim of reconstruction measures is to liquidate the pollution of the aquifer and establish the natural quality of groundwater. This can be done by pulling out of the polluted content from the contaminated layer using drainage boreholes, or by intensive flushing of the layer through ...