Претрага

Упит dcterms_subject_txt:fragmentation size

323 items

  • 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
    ... (lime) undefined >15 <3 2. The classification of fly ash according to the module R size ( ) ( )32 32 OFeMgOCaO AlOSiO R ++ + = (1) According to module R size, fly ash can be divided into: - silicate – calcium R < 2, - silicate R = 2 ÷ 6 ...
    ... Positive after 15 days 10 3000 10000 15 4000 15000 The intensity of these processes depends largely on the ash fineness (particle size and particle size distribution), so that the pozzolanic reactivity increases with the specific surface of ash. International standard ASTM C 311 describes ...
    ... Technical Gazette 23, 6(2016), 1839-1848 presence of certain phases in the system, the deformation of crystal lattice, the size of crystals. It can also be used for quantity analysis, or more precisely, for an estimation of different components share in the content of the sample ...

  • Towards more sustainable district heating systems in Serbia - Options and obstacles

    Marija Živković, Boban Pavlović, Dejan Ivezić, Miloš Tanasijević, Dejan Stojanović (2024)
    The major share of energy consumed in the building environment is dedicated to meeting heating needs, which makes this sector one of the key players in the transformation of the whole energy system. The accurate approach to the transition process assumes acting on both the demand and supply sides. Lately, the supply side has received more attention, as its transformation is one of the key steps of the energy transition process. District heating systems are recognized as substantial contributors ...
    energetska tranzicija, daljinsko grejanje, dekarbonizacija, obnovljivi izvori energije, prepreke, Srbija

  • Design of a sucker rod pumping system

    Ana Ponoćko (2024)
    For a long time in the history of oil production, sucker rod pumps have been the first and in many cases the only choice when it comes to mechanical extraction methods. Proper selection of each individual element of the system enables optimization, which entails benefits in the form of increased efficiency and reduced costs. The first part of the paper presents the underground and surface equipment of the rod pump and describes the operation of the entire system. The ...
    sucker rod pump, fluid production, mechanical extraction methods,, Prosper, QROD, RODSTAR
    ... based on the assumed condition of the pump and determine: minimal load on the sucker rods and pump unit, and if necessary, the counterweight size, reducer size, and motor power for the pumping installation. Design Methods: — API Method — Wave Equation API method This method was developed in ...
    ... RodStar lets you input a target production rate and simultaneously calculates strokes per minute, plunger size, and rod string design. It even suggests the appropriate pumping unit size. Alternatively, you can enter IPR data to have RodStar calculate the target production rate and design the ...
    ... Taper Top Steel Rod Lcading Min API Unit Rating Min NEMA D Motcor Size Polished Rod Power TVLcad SVLoad Design Inputs Unit Pump Depth Target Rate Stroke Rate (SPM) Surface Stroke Length Pump Diameter (D} Tubing Size Anchored Tubing Rod Type API Rod Number APIRod Grade Default Settings ...

  • 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

  • Preliminary regional landslide susceptibility assessment using limited data

    Igor Peshevski, Milorad Jovanovski, Biljana Abolmasov, Jovan Papic, Uroš Đurić, Miloš Marjanović, Ubydul Haque, Natasha Nedelkovska (2019)
    In this paper a heuristic approach for preliminary regional landslide susceptibility assessment using limited amount of data is presented. It is called arbitrary polynomial method and takes into account 5 landslide conditioning parameters: lithology, slope inclination, average annual rainfall, land use and maximum expected seismic intensity. According to the method, in the first stage, a gradation is performed for each of the carefully selected conditioning parameters by assigning so called rating points to the grid cells on which the ...
    klizišta, podložnost
    ... relation to the change in size of the zones with high and very high susceptibility (in relation to the initial basic models TLSR100/500) and compare these with the change in number of landslides, then it can be seen that different models show changes from –1.83% to 1.68% for the size and –2.64% to 1.71% ...
    ... most significant change in size of the area un- der high and very high susceptibility, and the least change in number of landslides in these zones, both with negative trends. On the other hand, the models WAP-TLSR100 and WAP- TLSR500 show the most significant decrease in size of the area, but in this ...
    ... cor- relation with a positive trend of increase both in the size and num- ber of landslides. This leads to the conclusion that the model WSI-TLSR100 is the most suitable to be applied for this particular case study re- gion, since the size of the area under high and very high suscep- tibility has reduced ...

  • Properties of fly ash and slag from the power plants

    Miloš Šešlija, Aleksandra Rosić, Nebojša Radović, Milinko Vasić, Mitar Đogo, Milovan Jotić (2016)
    This paper describes the physical, chemical and mineral properties of ash and slag, which were taken from thermal power plants Nikola Tesla A, Nikola Tesla B, Kostolac A and Kostolac B. The knowledge of the mineralogical material composition is important because the type of minerals directly determines the properties of the fly ash and slag and their possible application. Laboratory tests showed that ash and slag samples consist of the following minerals: amorphous materials, quartz, feldspar, mullite, melilite, cristobalite, ...
    fly ash, slag, physical composition, chemical composition, mineral composition, X-ray diffraction method
    ... and slag; • chemical analyzes of the ash and slag; • mineralogical tests of the ash and slag. The humidity samples, density of solid particles, grain size composition and pH value tests were done to determine the phy si- Figure 3. Location and coal �elds of the Kostolac basin (STOJANOVIĆ et al., 2012) ...
    ... Sample humidity was examined according to the standard EN 1328-1, the solid particles volume weight test followed the standard EN 1097-7, grain size composi- tion was tested according to EN 933-1, EN 451-2 and SRPS U. B1.018., and the pH value test was done according to SRPS H. C8.209. All the chemical ...
    ... type of crystal lattice to be determined, as well as the presence of certain phases in the system, the deforma- tion of the crystal lattice, and the size of crystals. It can also be used for quantity analysis, or more precisely, for an estimation of the proportions of the different components in the ...

  • 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

  • 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
    ... terraces. The size of the larger particles of AC2 (Fig 1a) corre- sponds to the size given by the provider (36–150 um), but smaller particles are also visible. Sla Fig in S1 File shows the image of AC1 with a larger amount of smaller particles in accordance with the particle size (75% < 40 um) ...
    ... crystal of extended (infinite) size [104]. Polycrystalline graphite exhibits a second peak at 1355 cm” that is assigned to the Ay, mode, which becomes Raman active for finite crystal size [104]. The intensity of that peak and the peak position are related to the crystal size [104] and depend on the ...
    ... repeated, but were found to be reproduc- ible. Two activated carbons were used as reference chars, AC1 (Fluka, particle size 75% < 40 um) and AC2 (Sigma Aldrich, particle size 36–150 um). For the measurements with nitro- gen adsorption and XPS, AC2 was washed several times with demineralized water ...

  • Integrating landslide magnitude in the susceptibility assessment of the City of Doboj, using machine learning and heuristic approach

    Cvjetko Sandić, Miloš Marjanović, Biljana Abolmasov, Radislav Tošić (2023)
    In this work, landslide assessment of the Doboj City area was modeled by combining machine learning and heuristic tools. The machine learning part was used to map the Morphometric factor. i.e. probability of landslides based on relation between the magnitude of events and morphometric parameters: elevation, distance to streams, slope, profile curvature, and aspect. The Random Forest and Support Vector Machines algorithms were implemented in the learning protocol, which included several strategies: balancing of the training/testing set size, algorithm ...
    podložnost na kliženje, magnituda klizišta, mašinsko učenje, heuristički pristup, Doboj

  • 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
    ... connected with lime mortar. 283 processed, rectan- gular, less often trapezoid stone blocks are embedded in the facade of the gate. An average size of blocks is 50/25 cm. The surface area of south facade is 32 m? and the surface area of the stone built part of the north facade is 11.4 m?. ...
    ... ” (Fitzner et al. 1995) in scientific literature ' known as Fitzne's model mapping. The standard classification scheme was modified to fit the size of built stone blocks in Dark Gate. A correlation scheme was developed for the monument in which all observed weathering forms were related to ...
    ... to ISCS Glossary (ICOMOS-ISCS 2008). For determination of damage categories, intensities of weathering forms were correlated with the average size of stone blocks, function of structural elements and monu- ment's defined cultural value (Fitzner and Heinrichs 2002). @ Springer 6186 Based ...

  • Mine ventilation system planning using genetic algorithms

    Nikola Lilić, Ranka Stanković, Ivan Obradović (1997)
    The most common problem in contemporary mining practice related to the planning and analysis of ventilation systems is the optimization of partially regulated air distribution in mine ventilation networks. This paper presents a two step optimization procedure for partly regulated air distribution in mine ventilation networks. The first step is the determination of air distribution in all branches using the well known Hardy-Cross method. In the second step the distribution and parameters of air flow regulators with minimum engaged ...
    coal, lignite, and peat; ventilation systems; coal mining; underground mining; ventilation; mathematical models; design; air flow; optimization; calculation methods

  • Geochemical study of U, Th and REE mineralizations in Jurassic sediments and hydrochemical characterization of groundwaters in Eastern Serbia – Case study: Plavna area

    Jovan Kovačević, Maja Todorović, Marina Ćuk, Petar Papić (2016)
    jurski sedimenti, uran, torijum, elementi retkih zemalja, podzemna voda, istočna Srbija

  • A proposal for the landslide damage questionnaire in suburban areas

    Uroš Đurić, Biljana Abolmasov, Miloš S. Marjanović, Sanja Jocković, Miloš D. Marjanović (2022)
    Landslides are one of the most often natural disasters that have an extensive impact on society including loss of life, destruction of infrastructure and properties, damage to land and loss of natural resources. Landslide losses can significantly vary and they depend on a variety of different criteria such as the size and type of landslide, lithological setting of terrain, the terrain slope gradient, the quality of materials used for construction, and the construction typology. Damage from landslides is usually ...
    istraživanja, objekti, klizišta, rizik, procena

  • Dating of alluvial sediments from borehole at the lower course of the Sava river and indications of the connection between their genesis and climate changes in the Pleistocene

    David Mitrinović, Jelena Zarić, Oliver Anđelković, Gyorgy Sipos, Dušan Polomčić, Milan Dimkić (2019)
    This paper analyses the way in which Pleistocene climate change and glaciations in Dinaric Mountains was reflected in the deposition of alluvial sediments in the Sava river Valley, using a case study of Belgrade Groundwater Source (BGS), the largest and most downstream alluvial water supply source along the Sava river. A stratigraphic analysis of the Quaternary sediments from two boreholes on this site, based on sediment dating, lithological members identification, grain size distribution analysis was performed. Comparison with the ...
    Pleistocene, Alluvial deposits, Climato-lithostratigraphy, Sava river, Belgrade groundwater source, Luminescence

  • Filling of dolines with aeolian sediments in the high-mountain karst of the Dinarides (Mt. Durmitor, Montenegro)

    Mirela Djurović, Violeta Gajić, Predrag Djurović (2022)
    Filling of dolines with aeolian sediments, one of the less frequently described ways in which they are filled, is analysed in the present study on an example of a doline in the high-mountain karst of the Dinarides. There is a series of deep dolines on a broad ridge (about 2450 m a.s.l.) on Mt. Durmitor (Montenegro) in the southeastern part of the Dinarides. The accumulation of very fine-grained sand that almost completely fills one of the dolines was analysed. ...
    Doline, Zapuna, Eolski sedimenti, Karst, Dinaridi, Crna Gora

  • Quantitative landslide risk assessment in the city of Tuzla

    Miloš Marjanović, Biljana Abolmasov, Cvjetko Sandić, Miralem Mulać, Petar Begović (2021)
    In the climate-changing conditions, geological environment interacts more dramatically with the urban fabric than before. The urbanization is expansive and more aggressive than before, but so are the weather extremes and long-term climate trends. In effect, many processes which can be triggered by either side, nature or engineering, are becoming more pervasive than before, and such is the case with landslides. Dealing and managing landslides requires few crucial steps, starting from collecting data on landslide location and typology – ...
    "landslides", "risk assessment"
    ... 2014), remote sensing image analysis; using point or polygon for landslide representation, based on landslide size; filtering only appropriate, shallow landslides, of sufficient size for the final inventory. SCG-XIII INTERNATIONAL SYMPOSIUM ON LANDSLIDES. CARTAGENA, COLOMBIA- JUNE 15th-19th-2020 ...
    ... and testing/validating parts; training the Machine Learning algorithm, Support Vector Machines in particular, over a reasonable training sample size (25-33%) using landslide inventory as a reference; establishing connection between landslide and non-landslide occurrences against the conditioning ...
    ... but it lacked desirable metadata, such as landslide typology, mechanism, metrics etc. Still, some filtering on the basis of the landslide shape and size was performed to limit the inventory classes to similar, shallow sliding or flowing events. Simple non-landslide, landslide and marginally stable ...

  • Comprehensive Profiling of Microbiologically Induced CaCO3 Precipitation by Ureolytic Bacillus Isolates from Alkaline Soils

    Olja Šovljanski, Lato Pezo, Jovana Stanojev, Branimir Bajac, Sabina Kovač, Elvira Tóth, Ivan Ristić, Ana Tomić, Aleksandra Ranitović, Dragoljub Cvetković, Siniša Markov (2021)
    MICP process, kinetic study, calcite, vaterite, MALDI-TOF identification, Bacillus licheniformis, Sporosarcina pasteurii
    ... and corners become less sharp during the time. On the other hand, crystals induced by B. lentus cells have evident different particle size distribution since the size of the obtained forms varies the most for both samples during the incubation period. The morphology of CaCO3 Microorganisms 2021, 9 ...
    ... morphology was analyzed using scanning electron microscopy (SEM Hitachi TM3030) under a high vacuum (acceleration voltage 15 kV, beam current 20 nA, spot size 1 mm) and a LeyboldHeraus L560Q sputter coating device was used for imaging and covering samples with gold, respectively. 3. Results and Discussion ...
    ... 2) were observed as reflected solid structures of each colony, but with different positions relative to the colony center. Furthermore, the shape and size of crystal Microorganisms 2021, 9, 1691 7 of 20 forms were different on the bacterial strain level. As expected, the inorganic deposit was not observed ...

  • Machine Learning and Deep Neural Network-Based Lemmatization and Morphosyntactic Tagging for Serbian

    Ranka Stanković, Branislava Šandrih, Cvetana Krstev, Miloš Utvić, Mihailo Škorić (2020)
    The training of new tagger models for Serbian is primarily motivated by the enhancement of the existing tagset with the grammatical category of a gender. The harmonization of resources that were manually annotated within different projects over a long period of time was an important task, enabled by the development of tools that support partial automation. The supporting tools take into account different taggers and tagsets. This paper focuses on TreeTagger and spaCy taggers, and the annotation schema alignment ...
    Part-of-Speech tagging, lemmatization, corpus, evaluation, Serbian, morphological dictionary
    ... Corpus of Contemporary Serbian as well as the Serbian literary corpus. The performance of developed taggers were compared and the impact of training set size was investigated, which resulted in around 98% PoS-tagging precision per token for both new models. The SR BASIC annotated dataset will also be published ...
    ... category values to texts where they were missing. The biggest challenge was to add new grammatical cate- gories to the Intera corpus. Having in mind its size, it had to be done automatically using morphological dictionaries introduced in Section 2.1. In the first step unambiguous in- formation was added ...
    ... 87,965 611,505 75,858 75,477 sr 100 40449 5053 5,056 952,291 118,238 117,529 819,360 101,830 101,177 Table 4: Training, development and test sets size distribution We were interested not only in the overall performance of developed taggers and models, but also in their perfor- mance for specific ...

  • Analiza uslova formiranja oticaja reke Resave (istočna Srbija)

    Vesna Ristić Vakanjac, Marina Mitrašinović, Veljko Marinović, Saša Milanović, Ljiljana Vasić, Branislav Petrović, Petar Vojnović (2023)
    Reka Resava zbog veličine sliva i količine vode koju daje Velikoj Moravi predstavlja jednu od najznačajnijih njenih desnih pritoka. U okviru njenog sliva jasno se izdvajaju gornji, geomorfološki raznolik deo sliva, koji je uglavnom izgrađen od karbonatnih sedimenata, i donji deo koji pripada Velikomoravskom basenu. Proticaj reke Resave se beleži u profilima Manastir Manasija koji kontroliše gornji deo sliva u iznosu od 358 km2 i Svilajnac, koji se nalazi na oko 3.5 km pre njenog ušća i koji kontroliše ...

  • Early–Middle Jurassic brachiopods from Ponor Mountain, Western Balkan Mountains, Bulgaria; taxonomy, biostratigraphy and occurrence in the context of the early Toarcian Oceanic Anoxic Event

    Barbara V. Radulović, Lubomir S. Metodiev, Neda Motchurova-Dekova, Platon Tchoumatchenco (2023)
    Brachiopods, taxonomy, biostratigraphy, early Toarcian Anoxic Event, Bulgaria