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Упит dcterms_subject_txt:Standards for LRs

1390 items

  • Polyhedral characteristics of the cosalite-type crystal structures

    Sabina Kovač, Predrag Dabić, Aleksandar Kremenović, Aleksandar Pačevski, Ljiljana Karanović, Marko V. Rodić, Martina Tribus (2019)
    kristalna struktura, kozalit, poliedarske karakteristike

  • VENTEX: An Expert System for Mine Ventilation Systems Analysis

    Ranka Stanković, Nikola Lilić, Ivan Obradović (1996)
    Analiza sistema za ventilaciju je komleksan proces, koji bazira na proračunu brojnih parametara, koji se odnose na: stanje mreže, provetrenost, stabilnost sistema, gubitke vazduha, klimatske uslove, gasno stanje, ugroženost od požara i opasne prašine. Navedeni problemi se uspešno rešavaju paketom SimVent, ali potpuno razumevanje i korišćenje dobijenih rezultata zahteva angažovanje iskusnog specijaliste iz oblasti ventilacije. Rešenje je nađeno u kreiranju ekspertnog sistema VENTEX, čija je baza znanja formalizacija ekspertskog znanja iz oblasti ventilacije rudnika. U radu je prikazana metodologija ...
    ekspertni sistem, ventilacija
    ... Измењено: 2023-10-14 04:20:47 VENTEX: An Expert System for Mine Ventilation Systems Analysis Ranka Stanković, Nikola Lilić, Ivan Obradović Дигитални репозиторијум Рударско-геолошког факултета Универзитета у Београду [ДР РГФ] VENTEX: An Expert System for Mine Ventilation Systems Analysis | Ranka Stanković ...
    ... ventilation systems analysis is the evaluation of the general ventilation state of the mine. An appropriate and reliable solution for this problem is vital for the safety of the working process in mines with underground exploitation. Contemporary mining theory already operates with a number ...
    ... interface and a working memory, but also a module for the interface with SimVent numerical routines, the simulation routines themselves, and a data base used by these routines /Fig. 3/. The main purpose of the user interface is to provide means for a successful dialogue, i.e. an exchange of ...

  • Spatial and temporal variability of precipitation in Serbia for the period 1961-2020

    Boško Milanović, Phillip Schuster, Milan Radovanović, Vesna Ristić Vakanjac, Shristoph Schneider (2017)
    У овом раду анализиране су месечне, сезонске и годишње суме падавина у Србији за период 1961–2010. Географска ширина, дужина и надморска висина 421 падавинске станице и карактеристике терена у њиховом блиском окружењу (нагиб и аспект терена у радијусу од 10 км око станице) коришћене су за развој регресионог модела на основу којег је прорачуната просторна расподела падавина. Приказан је просторни распоред годишњих, јунских (максималне вредности за скоро све станице) и фебруарских (минималне вредности за скоро све станице) падавина. Годишње ...
    padavine, distribucija godišnjih padavina, distribucija mesečnih padavina, Republika Srbija

  • Models of Determining the Parameters of Rock Mass Oscillation Equation with Experimental and Mass Blastings

    Suzana Lutovac, Branko Gluščević, Rade Tokalić, Jelena Majstorović, Čedomir Beljić (2018)
    ... Minerals 2018, 8, 70 2 of 18 that this is the parameter which best defines danger from shock and damages it may cause. Due to that, adequate standards for the protection from shock are based on data that refer to oscillation velocity [2,3]. As the relation between the rock mass oscillation velocity ...
    ... . . , vN be the rock mass oscillation velocity values obtained for corresponding reduced distances R1, R2, . . . , RN. Proceeding from the equation for the rock mass oscillation velocity, given by the Equation (1) we can assume, that for pairs (Rm, vm) the following relations are valid: vm = K·Rm −n ...
    ... blasting conditions and geological characteristics of the rock mass, and it is determined based on trial blasting for a specific work environment. Thus, this paper offers analysis of the method for determination of parameters of the rock mass oscillation equation, which are conditioned by rock mass properties ...

  • 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

  • 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
    ... carried out. For that purpose, the optimal conditions for the practical application in mortar and concrete production are defined. Tests related to the use of waste slag as a partial replacement for cement in the production of mortars and concrete are performed in accordance with certain standards, and the ...
    ... determined in accordance with standard EN 1015-10, on the specimens used for testing of mechanical strengths, e.g., on the prisms with dimensions 40 mm × 40 mm × 160 mm. Flexural strength was determined in accordance with standards EN 196-1, EN 1015-11 and was tested on the prisms with dimensions 40 mm ...
    ... 003. Superplasticizer was used for the improvement of the consistency of fresh concrete and the same quantity was added to all concrete mixtures. Mix proportions of concrete mixtures for 1 m3 of concrete are given in Table 3. Table 3. Mix proportion of concrete mixtures for 1 m3 of concrete. Component ...

  • An Efficient Class of Iterative Root-Finding Methods with Applications

    Dejan Ćebić, Nebojša Ralević (2021)

  • Spatial assessment of the areas sensitive to degradation in the rural area of the municipality Čukarica

    Natalija Momirović, Ratko Kadović, Veljko Perović, Miloš Marjanović, Aleksandar Baumgertel (2019)
    Nature and Landscape Conservation, Soil Science, Agronomy and Crop Science, Water Science and Technology

  • Improving efficiency of thermal power plants through mine coal quality planning and control

    Mirjana Banković, Dejan Stevanović, Milica Pešić, Aleksandra Tomašević, Ljiljana Kolonja (2018)
    Главни циљ контроле квалитета угља у рудницима лигнита је снабдевање термоелектрана угљем чији квалитет мора да се креће унутар одређених квалитативних ограничења. Карактеристике угља могу да утичу на ефикасност, поузданост и расположивост како котла тако и јединица за контролу емисије. У овом раду аутори су презентовали интегрисану симулацију рударског процеса као нови приступ у истраживању променљивости калоричне вредности угља приликом експлоатације комплексног лежишта лигнита. Резултати таквог приступа омогућавају драгоцен увид у перформансе континуалног рударског система у смислу контроле променљивости ...
    mine planning, variability of coal quality, simulation, coal blending

  • 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

  • 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
    ... According to experience, a clearance of 0.0254 mm (0.001 in) with a piston labeled as 1 according to API standards is typically used for low-viscosity fluids (0.001 to 0.02 Pas), while for very viscous fluids (> 0.4 Pas), a clearance of 0.127 mm (0.005 in) or a piston labeled as 5 is applicable ...
    ... manufacturer must provide the allowable clearance for the smooth rod stroke. The allowable clearance for steel rods is 609.6 mm (24 in) for depths less than 1219 m (4000 ft), and for greater depths, 152.4 mm (6 in) is used for every 304.8 m (1000 ft). For operation under harsh conditions where sand ...
    ... according to API (American Petroleum Institute) standards based on pumping conditions [7,3]: • 0.0254 mm (0.001 in) • 0.0508 mm (0.002 in) • 0.0762 mm (0.003 in) • 0.1016 mm (0.004 in) • 0.127 mm (0.005 in) According to API standards, these plungers are labeled as: -1, -2, -3, -4, and ...

  • An Experimental Investigation of the Environmental Risk of a Metallurgical Waste Deposit

    Jasmina Dedić , Jelena Djokic , Jovana Galjak, Gordana Milentijević, Dragan Lazarevic, Živče Šarkočević, Milena Lekić (2022)
    The aim of this study is to investigate the environmental risk of long-term metallurgical waste disposal. The investigated site was used for the open storage of lead and zinc waste materials originating from a lead smelter and refinery. Even after remediation was performed, the soil in the close vicinity of the metallurgical waste deposit was heavily loaded with heavy metals and arsenic. The pollutants were bound in various compounds in the form of sulfides, oxides, and chlorides, as well ...
    otpad od proizvodnje olova, remedijacija, rizik po životnu sreinu, BCR sekvencijalna ekstrakcija

  • Application of Expansive Mortars for the Formation of Artificial Screens During Blasting in Urban Areas

    Milanka Negovanović, Lazar Kričak, Stefan Milanović, Nikola Simić, Jelena Majstorović (2024)
    During construction of buildings in urban areas, sometimes there is a need to blast solid rock mass in the immediate vicinity of the surrounding buildings. In that case, the aim is not only to increase the efficiency of blasting, but also to reduce harmful effects of ground vibration induced by blasting. At the same time, it is very important to protect the buildings located in the safe zone from the blast site as well as remaining rock mass around ...
    expansive mortar, artificial screens, pressure, rock breaking, building foundation

  • Fuzzy optimization in hydrodynamic analysis of groundwater control systems: Case study of the pumping station “Bezdan 1”, Serbia

    Dragoljub Bajić, Dušan Polomčić (2014)
    A groundwater control system was designed to lower the water table and allow the pumping sta-tion “Bezdan 1” to be built. Based on a hydrodynamic analysis that suggested three alternative solutions, mul-ticriteria optimization was applied to select the best alternative. The fuzzy analytic hierarchy process methodwas used, based on triangular fuzzy numbers. An assessment of the various factors that influenced the selec-tion of the best alternative, as well as fuzzy optimization calculations, yielded the “weights” of the alternativesand the ...
    groundwater lowering, groundwater management scenario, fuzzy analytic hierarchy process,expert knowledge, triangular fuzzy numbers, linguistic variables
    ... (2003) introduced statistical methods to FAHP, for selecting the criterion that affected the end result (i.e. selection of alternative). Among the FAHP approaches mentioned above, the one devised by CHANG (1996) was used to arrive at the best alterna- tive for the groundwater control system of the “Be- ...
    ... a groundwater control system for the “Bezdan 1” PS, whose function is to lower the water table to below the design eleva- tion, so that the pumping station can be built. Three alternatives were considered, to ensure protection against groundwater intrusion and provide for unhin- dered construction of ...
    ... water table of the analyzed alternatives. For each alternative, the characteristics of the groundwater control system: the number of wells and their spatial distribution, and the time need- ed to achieve maximal lowering of the water table below the excavation for the “Bezdan 1” PS, were defined as follows: ...

  • The Newton method for solving nonlinear equations based on aggregation operators

    Nebojša M. Ralević, Dejan Ćebić (2019)

  • Mean-based iterative methods for finding multiple roots in nonlinear chemistry problems

    Dejan Ćebić, Nebojša M. Ralević (2021)
    нелинеарне једначине, поступци засновани на срединама, вишеструки корени,

  • Machine learning based landslide assessment of the Belgrade metropolitan area: Pixel resolution effects and a cross-scaling concept

    Uroš Đurić, Miloš Marjanović, Zoran Radić, Biljana Abolmasov (2019)
    Improvements of Machine Learning-based landslide prediction models can be made by optimizing scale, customizing training samples to provide sets with the best examples, feature selection, etc. Herein, a novel approach, named Cross-Scaling, is proposed that includes the mixing of training and testing set resolutions. Hypothetically, training on a coarser resolution dataset and testing the model on a finer resolution should help the algorithm to better generalize ambiguous examples of landslide classes and yield fewer over/underestimations in the model. This ...
    klizišta, podložnost, mašinsko učenje

  • 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

  • Pre-failure deformation monitoring as rockfall prediction tool

    Miloš Marjanović, Biljana Abolmasov, Zoran Berisavljević, Marko Pejić, Petko Vranić (2021)
    General Engineering
    ... parameters and compensate for the lack of specific data [1]. Suspicious rock faces can be monitored for longer periods, using multiple monitoring systems (primarily Terrestrial Laser Scanning - TLS), seasonally or annually, or even in real-time. This provides systematic data for better understanding ...
    ... the rockfall trajectories were simulated for various settings. The rock strata were also sampled for laboratory tests (unofficial data: UCS 80-100 MPa, Tensile strength 30-40 MPa, Bulk density 25 kN/m3), some fresh surfaces were scanned from close-range for potential roughness analyses, but this ...
    ... al. [4] reported successful application using similar approach TLS acquisition for road corridors, but with doubled frequency and reduced point spacing resolution (10-20 cm), suggesting a systematic and quick tool for rockfall inventorying. However, they extended their analysis towards precursor ...

  • Permanent GNSS monitoring of landslide Umka

    Mileva Samardžić Petrović, Jovan Popović, Uroš Đurić, Biljana Abolmasov, Marko Pejić, Miloš Marjanović (2020)
    Клизиште Умка је једно од највећих насељених активних клизишта у Србији. Активност клизишта Умка се прати већ више од 85 година, различитим геотехничким и геодетским техникама. Од 2010. године, активност kлизишта се континуирано прати у реалном времену аутоматизованим перманентним системом за праћење базираним на Глобалним навигационим сателитским системима (ГНСС). Поред тога, од 2018. године активност клизишта се додатно прати кинематичким ГНСС одређивањем положаја скупа карактеристичних тачака као и применом UAV фотограметрије. Главни циљ овог рада је приказ резултата опажања три ...
    клизиште, перманентно праћење, ГНСС
    ... network (P771) was used for point S3, while for point S4 existing trigonometric stone benchmark (1/P16) was used. All stable points were used as a base points for relative kinematic GNSS positioning with post- processing. In addition, the S4 had the additional purpose as a base for real-time kinematic ...
    ... solutions for a single landslide point position. More specifically, the final landslide points coordinates (E, N, h) were estimated by calculating the arithmetic mean for all four kinematic GPS / GLONASS solutions, with experimental standard deviation σE = 3 mm, σN = 4 mm, σh = 11 mm, for all three ...
    ... MONITORING OF LANDSLIDE UMKA 1. INTRODUCTION Over the past two decades, driven by the development of geodetic instruments for data acquisition and technology for data processing in real time, a wide range of different types of complex monitoring automated systems found its use in various ...