Претрага
30 items
-
A model for estimation of stress-dependent deformation modulus of rock mass
Slavko Torbica, Veljko Lapčević (2019)Slavko Torbica, Veljko Lapčević. "A model for estimation of stress-dependent deformation modulus of rock mass" in International Journal of Mining and Geo-Engineering (2019). https://doi.org/10.22059/IJMGE.2018.255295.594729
-
Relation between crustal stress and thickness of earth's crust
Slavko Torbica, Veljko Lapčević (2020)Slavko Torbica, Veljko Lapčević. "Relation between crustal stress and thickness of earth's crust" in Podzemni radovi (2020). https://doi.org/10.5937/podrad1935013T
-
Correlation of uniaxial compressive strength with the dynamic elastic modulus, p –wave velocity and s –wave velocity of different rock types
Knowing mechanical properties of rocks incorporated with ultrasonic waves velocities investigations provide a secure basis for mine modelling. Uniaxial compressive strength, dynamic elastic modulus and ultrasonic waves velocities are just some of the rock properties that indicate on presence of discontinuities, stratification and fissures of rocks. Determining the relationship of these rock properties testing the rock samples that are corresponding to different rock types extracted from different mineral deposits represents the core of this study. In this paper, we ...Jelena Majstorović, Miloš Gligorić, Suzana Lutovac, Milanka Negovanović, Luka Crnogorac. "Correlation of uniaxial compressive strength with the dynamic elastic modulus, p –wave velocity and s –wave velocity of different rock types" in Underground mining engineering, Рударско - геолошки факултет - Београд (2019)
-
Laboratory testing of fly ash
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... experiment, was done according to the standard EN 13286-42 [19]. 2.4.3 The modulus of elasticity The modulus of elasticity represents the relationship between stress and deformation. Physical dimension of the modulus is the stress and is expressed in MPa. The experiment was done according to ...
... primarily to stabilized bearing layers. The development of this method allows the parameter assessment, such as tensile strength, tensile deformation, modulus of elasticity, Poisson's ratio, at fail and other mechanical properties. For the experiment the cylindrical shape samples were used D = ...
... 47 C 6 % 209,52 L 6 % 286,90 C 6 % 161,05 3.5.3 The modulus of elasticity After 7 days of the sample storage in the wet chamber, the modulus of elasticity was tested and was in range from 58.000 to 289.000 kPa. The maximum modulus of elasticity is obtained by adding 4 % of the cement as ...Miloš Šešlija, Aleksandra Rosić, Nebojša Radović, Milinko Vasić, Mitar Đogo, Milovan Jotić. "Laboratory testing of fly ash" in Tehnički vijesnik (2016). https://doi.org/10.17559/TV-20150317171035
-
The number of nonunimodular roots of a reciprocal polynomial
Dragan Stankov (2023)We introduce a sequence Pd of monic reciprocal polynomials with integer coefficients having the central coefficients fixed as well as the peripheral coefficients. We prove that the ratio of the number of nonunimodular roots of Pd to its degree d has a limit L when d tends to infinity. We show that if the coefficients of a polynomial can be arbitrarily large in modulus then L can be arbitrarily close to 0. It seems reasonable to believe that if ...Algebraic integer, the house of algebraic integer, maximal modulus, reciprocal polynomial, primitive polynomial, Schinzel-Zassenhaus conjecture, Mahler measure, method of least squares, cyclotomic polynomialsDragan Stankov. "The number of nonunimodular roots of a reciprocal polynomial" in Comptes rendus mathematique, Elsevier France Editions Scientifiques et Medicales (2023). https://doi.org/10.5802/crmath.422
-
Control of substructure construction of railways in the Republic of Serbia
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 ...... layer are given. Table 1 shows the required values of the dynamic modulus of deformation Evd together with the required values of the modulus of deformation Ev2. Determining the correlation coefficient between the deformation modulus Ev2 and Evd can be applied in special cases when soil 602 STEPGRAD2022 ...
... compaction and bearing capacity of the earth carcass layers is assessed by the static deformation modulus Ev2, which is determined by the test plate, while the control is performed by the dynamic deformation modulus Evd, which is determined by the light falling load experiment with base plate Ø300 mm ...
... determination of the dynamic modulus of deformation, Evd is obligatorily performed along with other tests and the stated correlation relations. Due to the fact that it is not standardized in the Regulations for main railways, tests by determining the dynamic modulus of deformation Evd are not even listed ...Dragan Lukić, Dragoslav Rakić, Irena Basarić Ikodinović. "Control of substructure construction of railways in the Republic of Serbia" in International Conference On Contemporary Theory and Practice in Construction XV, Banja Luka 16-17 jun 2022., University of Banja Luka Faculty of Architecture, Civil Engineering and Geodesy (2022)
-
The number of unimodular roots of some reciprocal polynomials
Dragan Stankov (2020)We introduce a sequence P2n of monic reciprocal polynomials with integer coefficients having the central coefficients fixed. We prove that the ratio between number of nonunimodular roots of P2n and its degree d has a limit when d tends to infinity. We present an algorithm for calculation the limit and a numerical method for its approximation. If P2n is the sum of a fixed number of monomials we determine the central coefficients such that the ratio has the minimal limit. ...Algebraic integer, the house of algebraic integer, maximal modulus, reciprocal polynomial, primitive polynomial, Schinzel-Zassenhaus conjecture, Mahler measure, method of least squares, cyclotomic polynomialsDragan Stankov. "The number of unimodular roots of some reciprocal polynomials" in Cmptes rendus mathematique (2020). https://doi.org/10.5802/crmath.28
-
On the distribution modulo 1 of the sum of powers of a Salem number
Dragan Stankov (2016)It is well known that the sequence of powers of a Salem number θ, modulo 1, is dense in the unit interval, but is not uniformly distributed. Generalizing a result of Dupain, we determine, explicitly, the repartition function of the sequence , where P is a polynomial with integer coefficients and θ is quartic. Also, we consider some examples to illustrate the method of determination.Algebraic integer, the house of algebraic integer, maximal modulus, reciprocal polynomial, primitive polynomial, Schinzel-Zassenhaus conjecture, Mahler measure, method of least squares, cyclotomic polynomialsDragan Stankov. "On the distribution modulo 1 of the sum of powers of a Salem number" in Comptes rendus Mathematique (2016). https://doi.org/10.1016/j.crma.2016.03.012
-
A necessary and sufficient condition for an algebraic integer to be a Salem number
Dragan Stankov (2019)We present a necessary and sufficient condition for a root greater than unity of a monic reciprocal polynomial of an even degree at least four, with integer coefficients, to be a Salem number. This condition requires that the minimal polynomial of some power of the algebraic integer has a linear coefficient that is relatively large. We also determine the probability that an arbitrary power of a Salem number, of certain small degrees, satisfies this condition.Algebraic integer, the house of algebraic integer, maximal modulus, reciprocal polynomial, primitive polynomial, Schinzel-Zassenhaus conjecture, Mahler measure, method of least squares, cyclotomic polynomialsDragan Stankov. "A necessary and sufficient condition for an algebraic integer to be a Salem number" in Journal de theorie des nombres de Bordeaux (2019). https://doi.org/10.5802/jtnb.1076
-
The Reciprocal Algebraic Integers Having Small House
Dragan Stankov (2021)Algebraic integer, the house of algebraic integer, maximal modulus, reciprocal polynomial, primitive polynomial, Schinzel-Zassenhaus conjecture, Mahler measure, method of least squares, cyclotomic polynomialsDragan Stankov. "The Reciprocal Algebraic Integers Having Small House" in Experimental Mathematics (2021). https://doi.org/ 10.1080/10586458.2021.1982425
-
Rock slope stability analysis under Hoek–Brown failure criterion with different flow rules
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 analizaSvetlana Melentijević, Zoran Berisavljević, Dušan Berisavljević, Claudio Olalla Marañón . "Rock slope stability analysis under Hoek–Brown failure criterion with different flow rules" in Bulletin of Engineering Geology and the Environment , Springer (2024). https://doi.org/10.1007/s10064-024-03667-0
-
Structural and geochronological constraints from the Drina-Ivanjica thrust sheet (Western Serbia): implications for the Cretaceous–Paleogene tectonics of the Internal Dinarides
Kristof Porkoláb, Szilvia Kövér, Zsolt Benkó, Gabor Héja, Melinda Fialowski, Balázs Soós, Nataša Gerzina Spajić, Nevenka Đerić, László Fodor (2019)Internal Dinarides, Drina-Ivanjica thrust sheet, Deformation history, K–Ar dating, Obduction, Structural analysis... Karamata et al., 2000; Schmid et al. 2008; Schefer 2012). To separate the deformation of the lower plate related to ophiolite emplacement from younger collision-related deformation, a clear view on the deformation history is fundamental. The Internal Dinaric structural units like the Studenica ...
... thrust sheet exposed along the northern rim of this thrust sheet. The timing of D, deformation is constrained by K/Ar ages suggesting 135—150 Ma tectonic burial for the Drina-Ivanjica thrust sheet. D, deformation and metamorphism is correlated with the closure of the Vardar ocean by top-W to NW ...
... 1966—71). The Car- boniferous rocks have experienced low-grade metamor- phism and multiple phases of deformation (Milovanovic 1984; Djokovic 1985; Trivic et al. 2010). However, the timing of deformation events is still unclear: the only available age constraints for the metamorphism of the Drina-Ivanjica ...Kristof Porkoláb, Szilvia Kövér, Zsolt Benkó, Gabor Héja, Melinda Fialowski, Balázs Soós, Nataša Gerzina Spajić, Nevenka Đerić, László Fodor. "Structural and geochronological constraints from the Drina-Ivanjica thrust sheet (Western Serbia): implications for the Cretaceous–Paleogene tectonics of the Internal Dinarides" in Swiss Journal of Geosciences (2019)
-
Uporedna analiza stabilnosti završnih kosina površinskog kopa „Veliki Krivelj“
Mihajlo Topalović (2023)Površinski kop „Veliki Krivelj“ nalazi se u blizina grada Bora i u neposrednoj blizini sela Krivelj. Od 2018. godine je u vlasništvu kineske kompanije „Zijin“ koja ima udeo od 63% vlasništva celokupnog RTB-a Bor. Na površinskom kopu obavlja se masovna eksploatacija rude bakra opremom visokog kapaciteta. Za bušenje se koriste bušilice prečnika od 250 do 310 mm, a za utovar minirane rude i jalovine bageri čija je zapremina kašike 15 m3 i 22 m3. Za površinski kop „Veliki Krivelj“ ...Mihajlo Topalović. Uporedna analiza stabilnosti završnih kosina površinskog kopa „Veliki Krivelj“, 2023
-
Стратешко планирање функционалности подземних просторија моделом прогнозе деформација
Лука Црногорац (2023)Релативно велике деформације подградне конструкције у подземним рудницима угља у Републици Србији представљају један од главних проблема за постизање планиране производње угља. Деформације подграде су директна последица статичких и динамичких оптерећења стенске масе и у многоме зависе и од времена трајања изложености подграде утицају подземног притиска. Код ниско механизованог радног процеса долази до повећаног излагања подземних просторија утицају подземног притиска услед дугог производног циклуса који је често пропраћен застојима у раду. Веома често подземне просторије се санирају и по ...Лука Црногорац. Стратешко планирање функционалности подземних просторија моделом прогнозе деформација, Београд : [Л. Црногорац], 2023
-
Analysis of a simplified model for determining rock mass oscillation velocity at the Kovilovača open pit
... ongitudinal elastic waves C, = 6661.00[m/ s] , • velocity of transverse elastic waves C, = 2852.67[m/ s] ; = 62.46[GN/m2], • dynamic elasticity modulus FE„ lin • „dynamic Poisson' ratio //„„ — 0.39|iGN/m2] . 6.2 Method of blasting in the open pit Kovilovača Measurements of seismic shocks in ...Suzana Lutovac, Miloš Gligorić, Jelena Majstorović, Luka Crnogorac. "Analysis of a simplified model for determining rock mass oscillation velocity at the Kovilovača open pit" in 9th International Conference Mining and Environmental protection MEP, 24 – 27 May 2023, Sokobanja, Serbia, Belgrade : University of Belgrade-Faculty of mining and geology (2023)
-
Investigation of quantitative indicators of anisotropy based on longitudinal elastic waves propagation velocities with uncertainty
... use for creating reliable models. Further researches can be related to determine correlation between other mechanical properties such as Young’s modulus, Poisson’s ratio, bulk density and compressive strength in order to create an dynamic model of anisotropy investigation. Acknowledgement This ...
... several times per second because of its shortness, so this method is called impulse method. Elastic waves in rock or sample are representing deformation propagation, so depending of type of deformations, waves of different types can be caused: a) longitudinal waves b) transversal waves Today ...
... London: Taylor and Francis Group plc; pp. 749-756 PETRUŽÁLEK M. et al. (2008) Changes of anisotropy of p-wave velocity propagation during deformation process of rock samples. In: 28-European Conf. AE Testing, Ewgae 2008, Cracow UT. Cracow. SOUSA L. M. O. et al. (2005) Influence of microfractures ...Miloš Gligorić, Jelena Majstorović, Suzana Lutovac. "Investigation of quantitative indicators of anisotropy based on longitudinal elastic waves propagation velocities with uncertainty" in Underground Mining Engineering, Belgrade : University of Belgrade - Faculty of Mining and Geology (2018). https://doi.org/10.5937/PodRad1832001G
-
Geotehnički aspekti izgradnje visećeg pešačkog mosta u Starom gradu u Užicu
U radu su prikazani rezultati geotehničkih istraživanja za potrebe izgradnje visećeg pešačkog mosta preko klisure reke Đetinje u Užicu. Predviđeno je da most, sistema prednapregnute trake, omogući prelaz pešacima sa desne dolinske strane na stranu Starog grada, koja je opasana strmom liticom (cca. 40 m visine). Za potrebe formiranja geotehničkog modela i strukturnog sklopa krečnjačke stenske mase korišćen je postupak fotogrametrijskog snimanja dronom. Predviđeno je da se zatežuća sila (od oko 30 MN), koju most prenosi na obalni stub, ...fotogrametrija, stabilnost kosina, pukotine, prednapregnuta sidra, test granične nosivosti, paker (Ližonov) test... potrebe izgradnje mosta na starom gradu. Rudarsko-geološki fakultet, Beograd 2 Hoek, E., Diederichs, M.S. (2006) Empirical estimation of rock mass modulus. International Journal of Rock Mechanics and Mining Sciences, 43, 203-215 ttps://doi:10.1016/j.ijrmms.2005.06.005 3 Hoek, E., Carter, T.G., ...Zoran Berisavljević, Miloš Marjanović, Uroš Đurić. "Geotehnički aspekti izgradnje visećeg pešačkog mosta u Starom gradu u Užicu" in Zbornik radova / Međunarodno naučno-stručno savetovanje Geotehnički aspekti građevinarstva i zemljotresno inženjerstvo, Vrnjačka banja, 1-3. novembar 2023., Beograd : Savez građevinskih inženjera Srbije (2023.)
-
Mapping and classifying large deformation from digital imagery: application to analogue models of lithosphere deformation
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... vectors dx (the deformed quadrilaterals) is determined by: dx = FdX. First row, incremental deformation, second row, cumulative deformation. 2.4 General deformation described with the deformation gradient Any deformation that can be described by F, can be written as a serial combination of a simple shear ...
... vectors dx (the deformed quadrilaterals) is determined by: dx = FdX. First row, incremental deformation, second row, cumulative deformation. 2.4 General deformation described with the deformation gradient Any deformation that can be described by F, can be written as a serial combination of a simple shear ...
... our framework we observe all deformation as distributed, because PIV averages deformation within a certain spatial window. Hence, up to this point, we have described deformation in a continuum approach. For our application, deformation in crustal tectonics, deformation is dominantly localized along ...Taco Broerse, Nemanja Krstekanić, Cor Kasbergen, Ernst Willingshofer. "Mapping and classifying large deformation from digital imagery: application to analogue models of lithosphere deformation" in Geophysical Journal International, Oxford University Press (OUP) (2021). https://doi.org/10.1093/gji/ggab120
-
Gate Road Support Deformation Forecasting Based on Multivariate Singular Spectrum Analysis and Fuzzy Time Series
Luka Crnogorac, Rade Tokalić, Zoran Gligorić, Aleksandar Milutinović, Suzana Lutovac, Aleksandar Ganić (2021)Underground mining engineers and planners in our country are faced with extremely difficult working conditions and a continuous shortage of money. Production disruptions are frequent and can sometimes last more than a week. During this time, gate road support is additionally exposed to rock stress and the result is its progressive deformation and the loss of functionality of gate roads. In such an environment, it is necessary to develop a low-cost methodology to maintain a gate road support system. ...deformacije podgrade, lasersko skeniranje, višekanalna singularna spektralna analiza, prognoza, klasterisanje fuzzy vremenskih serija... to obtain high accuracy deformation data, and multivariate singular spectrum analysis to process them and forecast the future state of deformations. Fuzzy time series is used to classify deformation data into several independent groups with respect to the magnitude of deformation intensity. In this way ...
... type of support that can be used to decrease the progressive deformation. An effective deformation forecast can result in a decrease of costs and delays. There are many different approaches to obtaining future states of support deformation. Ding-Ping Xu et al. [1] compared the predictions from the rock–soil ...
... to obtain high accuracy deformation data, and multivariate singular spectrum analysis to process them and forecast the future state of deformations. Fuzzy time series is used to classify deformation data into several independent groups with respect to the magnitude of deformation intensity. In this way ...Luka Crnogorac, Rade Tokalić, Zoran Gligorić, Aleksandar Milutinović, Suzana Lutovac, Aleksandar Ganić. "Gate Road Support Deformation Forecasting Based on Multivariate Singular Spectrum Analysis and Fuzzy Time Series" in Energies, MDPI (2021). https://doi.org/https://doi.org/10.3390/en14123710
-
Steel Arch Support Deformations Forecast Model Based on Grey–Stochastic Simulation and Autoregressive Process
Relatively large deformations of the steel arch support in underground coal mines in the Republic of Serbia present one of the main problems for achieving the planned production of coal. Monitoring of the critical sections of the steel arch support in the underground roadways is necessary to gather quality data for the development of a forecasting model. With a new generation of 3D laser scanners that can be used in potentially explosive environments (ATEX), deformation monitoring is facilitated, while ...čelična podgrada, prognoza deformacija, vremenske serije, grey-stohastička simulacija, autoregresija, podzemni rudnik ugljaLuka Crnogorac, Suzana Lutovac, Rade Tokalić, Miloš Gligorić, Zoran Gligorić. "Steel Arch Support Deformations Forecast Model Based on Grey–Stochastic Simulation and Autoregressive Process" in Applied Sciences, MDPI AG (2023). https://doi.org/10.3390/app13074559