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Упит dcterms_subject_txt:laboratory tests

135 items

  • Application of machine learning for diagnosing the operation of a deep well pump in oil production

    Maja Trikić (2024)
    This paper will thoroughly examine how machine learning can improve the diagnosis of deep well pumps by analyzing the role and function of the pumps, dynamograms, sensor technologies, and diagnostic methods.Our analysis will provide insights into modern techniques and approaches for enhancing the performance and reliability of oil production systems, targeting cost reduction and increased operational efficiency.
    deep well pump, dynamograms, machine learning, diagnostics of operating coditions,Random Forest, XGBoost
    ... 50,098 Number of tests 9 3 9 3 Maximum accuracy (%) 86.005 84.516 97.900 98.174 Table 3. Organization of Tests into 4 Groups. Al tests were conducted with two descriptors and load values from the lower log In Group A, all classes had 30 samples in the training set. Tests were conducted using ...
    ... with 24 models trained on datasets with 30, 90, and 180 samples, evenly distributed among classes. The tests, on the other hand, were performed on a dataset with 50,098 samples. The aim of the tests was to assess the minimum number of samples required to achieve good accuracy and to determine the impact ...
    ... on the classification process. 61 The tests were organized into four groups (A, B, C, and D). Each group has characteristics that vary depending on the applied techniques and the number of samples per class.Table 3 shows the organization of the tests into groups GroupA GroupB GroupC Group D ...

  • Characterization and Environmental Evaluation of Recycled Aggregates from Construction and Demolition Waste in Belgrade City Area (Serbia)

    Filip Abramović, Miroslav Popović, Vladimir Simić, Vesna Matović, Radmila Šerović (2024)
    General Materials Science

  • Uniaxial compressive strength test before and after standard fire test on rock mass

    Stefan Mitrović, Goran Todorović, Bojan Kostić, Milica Mirković-Marjanović, Nikola Božović, Marija Krstić, Aleksandar Erić, Radovan Gospavić, Snežana Ilić, Aleksandar Kijanović (2022)
    ... Measuring ranges of type K thermocouples were - 270 ° C to 1372 ° C. Acquisition systems for monitoring standard fire tests in vertical furnace were made completely in Laboratory for thermotechnics and fire protection according to SRPS EN 1363-1. Standard fire development is described by a logarithmic ...
    ... actions in tunnels, such as fire, can also affect strength of surrounding rock. Due to structure of rock mass, it is necessary to conduct thermal tests on samples that must be formed and prepared in accordance with standard. A sample of rock material-sandstone was brought from location where ...
    ... Jointed Rock Model (AJRM) SRPS EN 1926:2007, Natural stone test method - Determination of compressive strength SRPS EN 1363-1:2014, Fire resistance tests - Part 1: General requirements 437 ...

  • Development of Integrated Fuzzy Model for Mine Management Optimization

    Miodrag Čelebić, Sanja Bajić, Dragoljub Bajić, Dejan Stevanović, Duško Torbica, Vladimir Malbašić (2023)
    Technoeconomic, environmental and safety criteria generally affect the management of metallic and non-metallic mining operations. The first basic question that needs to be addressed when planning ore mining is which methods are adequate and what is the optimal mining technology? Due to the complex geologic framework of ore deposits, geological exploration has rendered synonymous the inherent uncertainties, vagueness, and inaccuracies. As a result, subjective evaluation by engineers and expert experience have become increasingly important. Given that the natural language ...
    mining technology, expert evaluation, triangular fuzzy numbers, multicriteria decision making

  • 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 ...
    ... Remarkable number of geotechnical laboratory and terrain investigations were carried out for Preliminary Design needs during 2016 and 2017: 121 exploration boreholes, 23 Cone Penetration Tests, 105 Standard Penetration Tests, 2 dilatometer tests, 277 samples of soil and rock were tested ...
    ... piezometer constructions were built in, geophysical investigations (68 geoelectrical sounds, 18 refraction profiles), mineralogical- petrological tests (Rakic, 2017). It is important to mention research related to wider area of highway route which enabled registration of large regional structures ...

  • Development and Application of Methodology for Quantification of Overbreaks in Hard Rock Tunnel Construction

    Zoran Berisavljević, Dragoljub Bajić, Vojkan Jovičić (2023)
    A methodology for determining overbreaks in hard rock tunnel construction using the drill-and-blast technique is presented in this paper. The methodology was developed for and applied to crystalline medium- to thick-bedded limestone, but it can be used in any jointed hard rock mass. Overbreaks are inevitable in hard rock tunnelling in a low-confinement environment (shallow tunnels up to several hundred meters deep) as a result of wedge failures along unfavourably oriented discontinuities caused by blasting. It is widely accepted ...
    hard rock, drill-and-blast, geological overbreak, technological overbreak, stability criterion, discontinuity orientation, tunnel construction

  • Density maps from gravity inversion as a tool for the basin basement analysis and imaging

    Ivana Vasiljević (2023)
    Previously devised method for density mapping of the Cenozoic basin’s basement is further developed in order to improve the visualization and geological interpretation of the results. The method combines gravity-density inversion with forward modeling and requires gravity anomaly and depth-to-basement data. Although it was primarily designed for application in well-researched basins, such as Pannonian basin, method does not require further constrains. An information on density distribution in the Cenozoic sediments (from density logging or core density measurements) is important ...

  • Analiza nosivosti vertikalno opterećenog šipa za potrebe izgradnje petlje „Merošina 1“ na autoputu E-80 deonica: Niš – Merošina

    Dragoslav Rakić, Nikola Božović, Miloš Stevanović, Milan Bogdanović (2023)
    U Srbiji je počela izgradnja autoputa E-80 koji će predstavljati saobraćajno čvorište zapadnog Balkana i biće deo glavne regionalne transportne mreže jugoistočne Evrope. Njegova ukupna dužina kroz Srbiju iznosi 77 km, a prva deonica u dužini od 5.5 km je završena i puštena u saobraćaj krajem jula 2023. god. To je prva od četiri deonice Sektora 1 čija je dužina 32.65 km. U sklopu petlje „Merošina 1“ izgrađen je nadvožnjak koji je oslonjen na devet stubnih mesta na međusobnom ...
    petlja Merošina 1, šip, probno opterećenje šipa, projektni pristup, granična stanja

  • 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
    ... of coal [2]. Serbia produces about 5 million tons of fly ash annually during coal combustion in the power plants [3]. The samples subject to laboratory tests were taken from the thermal power plant Nikola Tesla A (PPNT A) in Obrenovac. This paper presents the pozzolanic, mechanical, chemical and ...
    ... Измењено: 2023-10-14 03:38:35 Laboratory testing of fly ash Miloš Šešlija, Aleksandra Rosić, Nebojša Radović, Milinko Vasić, Mitar Đogo, Milovan Jotić Дигитални репозиторијум Рударско-геолошког факултета Универзитета у Београду [ДР РГФ] Laboratory testing of fly ash | Miloš Šešlija, Aleksandra ...
    ... mineral composition and properties of fly ash obtained in the combustion process in a PPNT A with 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 Lexical Approach to Acronyms and their Definitions

    Cvetana Krstev, Duško Vitas, Ranka Stanković (2015)
    In this paper we present a comprehensive approach to acronyms for Natural-Language Processing (NLP) of Serbian texts. The proposed procedure includes extraction of acronyms and their definitions that are usual Multi-Word Units (MWUs), shallow parsing of MWUs that enables MWU lemmatization and production of entries in morphological electronic dictionaries, both for MWU and acronyms, that are provided with grammatical, syntactic, semantic and domain information. This approach enables representation that reflects complex relations between acronyms and their definitions.
    ... acronyms additional tests were performed. For instance, the ending -u is used for dative and loca- tive masculine forms, while the same ending is used for accusative feminine forms. Therefore, in order to confirm the feminine gender we used two tests (13). The similar tests were performed for the ...
    ... N+NProp +Org+DOM=Mil+ACR=KFOR+SIN=AANNxNx(plu) :fp3q:fp6q:fp7q (a form of a proper name in dative, instrumental and locative case) 6. Performing some tests on a large corpus in or- der to obtain information about behavior of acronyms obtained as result of Step 4: do they inflect, what is their grammatical ...

  • Validation of vulnerability assessment by means of the Time Dependent, Model: case study from the Slovenian karst catchment

    Vladimir Živanović, Nataša Ravbar, Igor Jemcov (2019)
    Groundwater vulnerability assessment methods are continuously being developed and existing methods are very often modified to provide better simulation of natural protection conditions and more objective results. Most frequently used methods are based on calculation of predefined parameters influencing water infiltration and underground flow, which can often lead to bias conclusions related to vulnerability evaluations. Some other methods, like the Time Dependent Model (TDM) are based on an approach, where parametrization is obtained at the final stage of the ...
    Ocena ranjivosti podzemnih voda, karstne podzemne vode, TDM metoda, delineacija sanitarnih zona, Slovenački karst

  • Analysis of the Influence of Burden Deviation from the Designed One on the Intensity of the Blast Vibration

    Stefan Milanović, Lazar Kričak, Milanka Negovanović, Nikola Simić, Jovan Marković, Nikola Đokić (2023)
    This paper presents an analysis of the influence of burden deviation from the designed one on the intensity of blasting vibrations through the use of laboratory and field examinations. By definition, the burden represents the shortest distance from the axis of an explosive column charge to the free surface. It should be measured along the entire hole length, although, in practice, it is often measured only on the bench surface as the shortest distance from the axis of the ...
    linija najmanjeg otpora, 3D model, miniranje, potresi usled miniranja, slobodna površina

  • 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

  • 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
    ... minimal amounts (slag/silica fumes = 88%/12%). The maximal possible cement replacement was 20% with 17.8% of slag and 2.2% of silica fumes. The leaching tests were also performed in accordance with the standard EN 12457-2 on the mortar with 20% of cement replacement. The leaching was carried out on crushed ...
    ... with waste slag was 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 ...
    ... 2420.31 (0.981) 2415.26 (0.981) 2407.86 (0.981) Assumed aer content ~2% ~2% ~2% ~2% ~2% 2.3. Characterization of Mortar and Concrete Samples 2.3.1. Tests on Mortar Samples Consistency was determined by the flow table in accordance with the standard EN 1015-3. For the testing, a metal conical mold was ...

  • Clockwise rotation in the Serbian segment of the Vardar zone and in the Danubicum of Eastern Serbia - tetonic implication

    Vesna Lesić, Emo Marton, Vesna Cvetkov, Dragana Tomić (2015)

  • Примена нумеричких метода у моделовању тецишта са освртом на различите реолошке услове

    Јелка Крушић (2023)
    Тецишта су комплексне појаве нестабилности које захтјевају истраживања и испитивањакоја до сада нису рађена код нас у области геотехнике. По механизму, начину активирањаи понашању покренутог материјала се знатно разликују од клизишта. Циљ оведисертације је била примјена нумеричких модела пропагације тецишта на примјеру двијепојаве које су се десиле у Србији као посљедица дјеловања циклона Тамара. Детаљноистраживање тецишта подразумијева теренско картирање, теренска истраживања илабораторијска испитивања одабраних узорака са терена. Од теренских истраживања напримјеру тецишта Селанац урађена су геофизичка истраживања Електричнетомографије док ...
    тециште, нумерички модели пропагације, циклон Тамара, геофизичка истраживања, лабораторијска испитивања, Селанац, Лева река, RAMMS, SPH geoflow, реолошки модел

  • Дефинисање механичких својстава алтерисаног стенског материјала лабораторијским методама

    Вељко М. Рупар (2022)
    Основни циљ овог рада је да представи методологију одређивања механичких својстава хетерогеног стенског масива који изграђују дацит (Д) и алтерисани дацит (АД), где је уочена је зона постепеног преласка од алтерисаног дацита до дацита. Механичка својства стенског масива у тој зони утврђена су на основу лабораторијских испитивања једноосне и троосне чврстоће на притисак стенског материјала композитних узорака. Композитни узорци су се састојали од дискова стенског материјала, при чему је висина дискова h дефинисала различити процентуални удео појединог стенског материјала, ...
    дацит, алтерисани дацит, једноосна чврстоћа на притисак, троосна чврстоћа на притисак, композитни узорци, механика стена, стабилност косина

  • Investigation of nanostructured Ca0.9Er0.1MnO3 obtained by sucrose nitrate procedure

    Tijana B. Vlašković, Bojana Laban, Maja Milošević, Maria Čebela, Vladimir Dodevski, Milena Rosić (2023)
    ... produced by the selective laser sintering technique.The analysis of the determination of the stress intensity factor includes experimental and numerical tests. For this purpose, two geometries of specimens were used. Flat specimens with crack loaded in tension and ring specimens loaded on the inner wall ...

  • An aproach to Implementation of blended learning in a university setting

    Ivan Obradović, Ranka Stanković, Olivera Kitanović, Jelena Prodanović (2011)
    ... materials, teachers have the possibility of posting various announcements related to their course, test and exam results, examples of previous tests or lists of oral exam topics, links to internal or external resources, etc. Figure 1: FMG CMS web page The FMG CMS database contains ...
    ... for a forthcoming instruction class, download course materials or get informed about their test and exam results, date and time of forthcoming tests and exams, etc., without being physically present in the FMG building. Course materials available on the portal to date cover approximately ...
    ... users and additional 1GB of RAM is needed, the 4GB of available memory turned out to be insufficient in some situations, especially during course tests, when approximately 50 students concurrently accessed the system. It has been estimated that this amount of memory would be sufficient for only ...

  • Paleomagnetic study of Jurassic-Early Cretaceus sediments in the Danibicum of Eastern Serbia

    Vesna Cvetkov, Emo Marton, Vesna Lesić, Dragana Tomić (2015)
    ... the obtained remanent magnetization for the localities is of pre or post–folding age on locality level and regional level we performed the fold tests. As a results of demagnetization, well defined, apparently single component remanences were isolated. The statistical parameters on locality ...
    ... geofiziku, Đušina 7, 11000 Beograd, Srbija, e-mail: vesna.cvetkov@rgf.bg.ac.rs 2 Geological and Geophysical Institute of Hungary, Paleomagnetic Laboratory, Columbus u. 17-23, H-1145 Budapest, Hungary 3 Republički geodetski zavoda, Odeljenje za geomagnetizam i aeronomiju, Bul. Vojvode Mišić 39 ...
    ... Geophysics, Djušina 7, 11000 Belgrade, Serbia, e-mail: vesna.cvetkov@rgf.bg.ac.rs 2 Geological and Geophysical Institute of Hungary, Paleomagnetic Laboratory, Columbus u. 17-23, H-1145 Budapest, Hungary 3 Republic Geodetic Authority, Department of Geomagnetism and Aeronomi, Bul. Vojvode Mišić 39, ...