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Упит dcterms_subject_txt:Nanocrystalline material

342 items

  • Definisanje parametara čvrstoće na smicanje kod izvođenja kosina u ispucalom stenskom masivu

    Zoran M. Berisavljević (2016-04-01)
    Definisanje parametara čvrstoće na smicanje ispucalih stenskih masa predstavlja jedanod najzahtevnijih zadataka mehanike stena. Geotehnička istraživanja su uglavnomograničena na rezultate laboratorijskih ispitivanja malih makroskopski homogenihuzoraka, sa kojih se vrši ekstrapolacija rezultata na terensku razmeru. Ispitivanja semogu vršiti in situ, ali su i ona ograničena veličinom korišćene aparature imikrolokacijom na kojoj se vrše ispitivanja. Pored toga, moguće je vršiti različitaispitivanja na fizičkim modelima, koja su veoma složena i skupa. Ekstrapolacijapodataka sa malog uzorka na terensku razmeru daje mnogo bolje rezultate ...
    naponsko stanje, ispucalost, heterogenost, čvrstoća na smicanje, geološki indeksčvrstoće, Hoek-Brownov materijal, kompozitni uzorci, dezintegracija, povratna analiza

  • 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

  • Control of substructure construction of railways in the Republic of Serbia

    Dragan Lukić, Dragoslav Rakić, Irena Basarić Ikodinović (2022)
    Контрола збијености природног тла (у ископу) или збијеног у насипу при изградњи саобраћајница представља један од основних облика контроле квалитета доњег строја. Код изградње брзих саобраћајница (аутопутеви и брза железница) приоритет је постизање високог нивоа контроле извршених радова. У циљу онемогућавања диференцијалног слегања (при изградњи насипа), или промене запремине услед допунског збијања материјала, које неминовно доводе до деформација, потребно је извршити оптимално збијање материјала. У оквиру овог рада приказује се техничка регулатива која регулише контролу збијености при изградњи железничке ...
    доњи строј, техничка регулатива, насип, збијеност, контрола
    ... chemical stabilization is used to improve the load-bearing capacity of the material. The foundation soil planum must meet the geometric requirements [3:6-6]: flatness of the soil material layer 30 mm/4 m; flatness of the stone material layer 50 mm/4 m; the maximum allowed deviation of the elevation of the ...
    ... construction of the embankment), or to change the volume due to additional compaction of the material, which inevitably leads to deformations, it is necessary to perform optimal compaction of the material. Within this paper, the technical regulations governing the control of compaction in the construction ...
    ... is used: capillary rise resistant material; unbound aggregate, grain size 0/125 mm; percentage of aggregate grains below 0.063 mm < 12%; percentage of aggregate grains below 0.02 mm < 5%; smaller contain more than 10% of fractions smaller than 0.02 mm. The material in the transition layer should meet ...

  • Mapping and classifying large deformation from digital imagery: application to analogue models of lithosphere deformation

    Taco Broerse, Nemanja Krstekanić, Cor Kasbergen, Ernst Willingshofer (2021)
    kontinentalna tektonika: kompresija, kontinentalna tektonika: ekstenzija, kontinentalna tektonika: transkurentni i transformni rasedi, pukotine, rasedi, zone snažnih deformacija, kinematika deformacija kore i omotača, teorijska mehanika, modelovanje
    ... these displacements to a Lagrangian (material-fixed) frame. Namely, we are primarily interested in the deformation of material, rather than the deformation at a location in space through which material advects. One can use the Eulerian displacements to follow material, provided that PIV-derived displacements ...
    ... relates the deformed state to the undeformed state. A material vector dX that runs from point P to Q (i.e. a side of a small material element) in the original configuration, to the material vector in the deformed configuration dx, with the material that first occupied points P and Q now in points p and ...
    ... at reverse faults, footwall material that was first at the surface will be buried by the hanging wall material and, therefore, no longer be at the surface. Subsequently, that material will no longer be visible with PIV, resulting in an accumulation of virtual material points at the fault trace. We ...

  • Application of stochastic models for mine planning and coal quality control

    Dejan Stevanović, Božo Kolonja, Ranka Stanković, Dinko Knežević, Mirjana Banković (2014)
    ... prediction of the performance of stock- piling systems for which reclaim slices include unequal amounts of material from the layers of material stacked, fig. 3. Quality of the reclaimed material is calcu- lated as the weighted average of pieces of the layers that are taken from the bed. In this calcu- ...
    ... prediction of the performance of stock- piling systems for which reclaim slices include unequal amounts of material from the layers of material stacked, fig. 3. Quality of the reclaimed material is calcu- lated as the weighted average of pieces of the layers that are taken from the bed. In this calcu- ...
    ... and added mass. The last variable can signifi- cantly reduce pile variability when a large material amount is homogenized, and variability among the lots decreases [4, 5]. The deposition sequence of the material also is able to affect grade predictability of each pile, requiring a more careful mining ...

  • 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
    ... there is no planned waste disposal, in order to get a more realistic picture in terms of the quality of waste material, samples were taken by the square method from different places so that material of different ages was included. After sampling, the samples were mixed, homogenized and the required amount ...
    ... observed that with the increasing cement replacement by waste material, the strength of mortar specimens decreased at an early age (7 days). On the other hand, with increasing age (28 and 90 days) the strength of mortar with the waste material approached the values of the reference mortar. This is attributed ...
    ... mortars with a higher content of waste material is the lower quantity of free water necessary for the hydration of cement materials in the hardening period. Based on the results of concrete consistency testing, it can be concluded that as the content of waste material increased, the size of the slump decreased ...

  • The Importance of Geotechnical Investigations for the Construction of Transfer Station „Prelići“ on Landfill in Cacak – Serbia

    Dragoslav Rakić, Irena Basarić, Jovana Janković, Tina Đurić (2019)
    For the purpose of the facilities construction within the transfer station „Prelici“ in Cacak, specific geotechnical investigations were carried out based on which the technological project with the facilities schedule was developed. Significant deviations in relation to the presented results were determined during earthworks, so the additional geotechnical investigation works were carried out. Since the new investigation works have determined a different cross section of the terrain, it was proposed to move the planned facilities which led to the ...
    landfill, geotechnical investigations, transfer station
    ... into material of old municipal waste (MSW-kO), which was created by the former active waste disposal on the whole southern part of the site and into material made by remediation measures of this landfill area, i. e. its covering of inert material (MSW-prk). Both of these landfill material layers ...
    ... landfill, and ranges from 2.2 to 4.0 m (Figure 3). The inert earth material, which represents old waste cover (MSW-prk), is a clay-silty composition, black to dark brown, insufficiently compact and loose. It is mainly a construction material with rare fragments of brick and concrete, but gravel fragments ...
    ... area was not used for waste disposal. However, on the southern part of the site, the surface is built of municipal waste covered with inert earth material (Figure 2). Figure 2. The situation of the terrain with the original schedule of the transfer station facilities In addition to the significant ...

  • Cutting Resistance Laboratory Testing Methodology for Underwater Coal Mining

    Vladimir Čebašek, Veljko Rupar, Stevan Đenadić, Filip Miletić (2021)
    Geology,Geotechnical Engineering and Engineering Geology
    ... resistance of the excavator, values for rock material strength index proposed by Protodjakonow [1,14] were used. Rock material strength index, fpr, proposed by Protodjakonow is determined by the uniaxial compressive strength, σc (MPa), of the rock material, for which he gave the relationship: fpr = σc/10 ...
    ... ed and accepted laboratory testing methods to determine the cutting resistance of a material to be excavated, even though several labora- tory methods are available to determine the cutting resistance of the material in the seams of surface mines. The Lübeck Works of Orenstein and Koppel developed a ...
    ... bucket knife or tooth in the laboratory on the drilling core samples or block-shaped rock material samples. Consequently, the testing method is most used for determination of the cutting resistance of the material to be excavated. 2. Coal Mining in Underwater Pit “Kovin” Exploration work in the coal ...

  • 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

  • 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

  • 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
    ... Degree-covering of surface Low Low High _ _ Mass of detaching stone material Medium · High _ Mass of detaching stone material High _ Thickness of the scales (mm) 10 Mass of detaching stone material Medium · High _ Number and dimensions of fissures – Small Low Low ...
    ... was not observed. As far as groups of weathering forms are concerned, most dominant are loss of stone material, deposits in the form of crusts and detachment (Fig. 4). Loss of stone material is generally presented as surface recession and relief, only occasionally as outburst. Black crusts and ...
    ... heavy damage are blocks with a significant loss of material that disrupts the original appearance of the stone element (Fig. 4b, d, f damage cate- gory 4 and 5 in Table 1). Moderate damage is manifested on stone blocks where loss of material is superficial (Fig. 4c, e damage category 3in Table ...

  • Production information system of the Pljevlja coal mine

    Božo Kolonja, Ranka Stanković, Filip Vuković (2018)

  • Poboljšanje geotehničkih uslova izgradnje nasipa upotrebom geosintetika

    Anastasija Radovanović (2024)
    Za potrebe izrade rada na Master akademskim studijama ,,Rudarsko-geološkog fakulteta,,, studijskog programa Geotehnika, pod mentorstvom prof. dr Gordane Hadži-Niković , izvršena je detaljna analiza stabilnosti kosina nasipa na Vranjskoj petlji. Geotehnička istraţivanja i ispitivanja terena izveo je “Zavod za geotehniku iz Instituta za puteve a.d. Beograd”, a investitor je “Javno preduzeće, Putevi Srbije”.Metodološki pristup koji je korišćen za analizu stabilnosti kosina nasipa jeste kabinetsko istraživanje dostavljene dokumentacije i geostatički proračuni analize stabilnosti kosina nasipa, korišćenjem savremenih softverskih alata.Krajnji zaključak izvedenih istraţivanja je da ...
    tlo, nasip, analiza stabilnosti, faktor sigurnosti, geosintetici
    ... propisima za tlo sa uglom unutrašnjeg trenja o > 32, tako da preporučeni materijal zadovoljava minimalni faktor sigurnosti i mogao bi se ugraditi material lošijih fizičko-mehaničkih karakteristika. Rezultati su prikazani u Prilozima 7.17-7.24. Pored navedenih analiza i proračuna urađen je ı proračun ...
    ... 11 0 12 0 13 0 50 40 Safety Factor 0.000 0.500 1.000 1.500 2.000 2.500 3.000 3.500 i. Unit Weight 'Cohesion i 4.000 Material Name | Color (kN/m3) Strength Type (kN/m2) Phi | Water Surface | Hu Type | Ru 4.500 Nasip 18 Mohr-Coulomb 0 32 None o 5.000 al-prp 19 Mohr-Coulomb ...
    ... 1.500 2.000 2.500 3.000 3.500 4.000 4.500 5.000 5.500 6.000+ Prilog 7.2. Unit Weight (kN/m3) CCoohesion Color (kN/m2) Material Name Strength Type Phi | Water Surface Hu Type Nasip 18 Mohr-Coulomb 0 32 None o 19 Mohr-Coulomb 0 31 None 0 al-prp al-ps 19 Mohr-Coulomb 0 ...

  • 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
    ... The chemical properties of fly ash and slag are the most important indicator in the evaluation of their suitability as a building material. Know- ledge of the material mineralogical composition is significant be- cause the type of minerals directly determines the properties of fly ash and slag and ...
    ... in the environment. Slag is a mineral mixture that consists of ma- terial melted in the combustion process and other parts of non- combustible material. It falls through the latticed stokehole and is rapidly cooled and extinguished in water. The fly ash and slag landfills in Serbia occupy an area ...
    ... & ILIĆ, 2007). All the negative environmental indicators caused by fly ash and slag can be eliminated or reduced if they are used as build- ing material for road construction and other trafficked areas. The using of fly ash and slag as secondary materials for road construc- tions, saves huge amounts ...

  • Rock slope stability analysis under Hoek–Brown failure criterion with different flow rules

    Svetlana Melentijević, Zoran Berisavljević, Dušan Berisavljević, Claudio Olalla Marañón (2024)
    The stability analysis of homogeneous rock slope following the Hoek–Brown failure criterion under the hypothesis of different flow rules is performed based on limit equilibrium and finite element methods. The applied failure criterion is the generalized Hoek–Brown that can be introduced as a shear/normal function in analysis applying different flow rules. The results are compared with those obtained by the application of equivalent shear strength parameters of the Mohr–Coulomb criterion, considering that this is still the most widely used ...
    Kružna klizna površ, Huk-Braunov kriterijum loma, Kriterijum popuštanja, Smičuća/normalna funkcija, Nivo napona, Verovatnoća i parametarska analiza

  • Manganese-pyromellitate complex as a precursor for preparation of spinel Mn3O4

    Lidija Radovanović, Željko Radovanović, Aleksandar Kremenović, Bojana Simović, Milica V. Vasić, Jelena Rogan (2022)
    In recent years, thermal decomposition studies of transition metal complexes with benzenepolycarboxylate ligands have become an area of a great importance due to the possibility of obtaining useful metal oxides with desirable electrical, magnetic and catalytic properties [1]. As a contrast to conventional methods for the preparation of metal oxides, such as hydrothermal or sol–gel treatment, thermolysis is faster, more efficient ...

  • Non-Detonating Chemical Mixture for Non-Invasive Methods of Rock Breaking

    Lazar Kričak, Milanka Negovanović, Nikola Simić, Stefan Milanović (2024)
    Within the Innovation developed several different non-detonating chemical mixtures for non-invasive methods of rock breaking. Laboratory and polygon tests gave the satisfactory results and knowledge enough to start the practical experiments in the field. The basis of this innovation is a theoretical assumption that certain chemical mixtures release a large quantity of gases during combustion. If these gases are found in the enclosed space a growing pressure on the walls of the chamber in which combustion takes place will ...
    non-detonating, chemical mixture, rock breaking, borehole pressure

  • 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

  • Constitutive Model for Analysis of Long-Term Municipal Solid Waste Landfill Settlement

    Irena Basarić Ikodinović, Dragoslav Rakić, Mirjana Vukićević, Sanja Jocković, Jovana Janković Pantić (2022)
    Large long-term settlement occurs at the municipal solid waste landfills over an extended period of time which may lead to breakage of the geomembrane, damage of the cover systems, other protective systems or facilities constructed on top of a landfill. Also, municipal solid waste is an extremely heterogeneous material and its properties vary over location and time within a landfill. These material characteristics require the formulation of a new constitutive model to predict the long-term settlement of municipal solid ...
    constitutive model, finite element analysis, municipal solid waste, settlement

  • Hybrid Model for Optimisation of Waste Dump Design and Site Selection in Open Pit Mining

    Aleksandar Doderovic, Svetozar-Milan Doderovic, Sasa Stepanovic, Mirjana Bankovic, Dejan Stevanovic (2023)
    Waste management is an unavoidable technological operation in the process of raw material extraction. The main characteristic of this technological operation is the handling of large quantities of waste material, which can amount to several hundred million cubic metres. At the same time, this operation must comply with all administrative and environmental standards. Therefore, optimising waste rock management (particularly haulage and dumping) has the potential to significantly improve the overall value of the project. This paper presents a hybrid ...
    projektovanje odlagališta i izbor lokacije, hibridni model, optimizacija, genetski algoritam