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Wyniki wyszukiwania dla: EARTH FAULT CURRENTS
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Analog fault signature based on sigma-delta modulation and oscillation-test methodology.
PublikacjaW artykule dokonano przeglądu prac z zakresu testowania układów elektronicznych metodą oscylacyjną. Wskazując na niedostatki aktualnie stosowanej techniki testowania oscylacyjnego zaproponowano nową sygnaturę uszkodzeń dla układów analogowych. Proponowany parametr diagnostyczny jest wydobywany z odpowiedzi czasowej oscylatora testującego, w układzie złożonym z detektora szczytowego, modulatora sigma-delta oraz licznika rewersyjnego....
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Reducing common mode voltage and bearing currents in quasi - resonant DC - link inverter
PublikacjaIn the paper, a concept of separation of an inverter-fed induction motor drive from its mains supply by two transistor switches inserted in the dc-link circuit is reexamined based on the proposed parallel quasi-resonant dc-link inverter (PQRDCLI). The objective of the paper is to show an advantage of the proposed topology in limiting high frequency common mode voltage and bearing currents. In the laboratory setup, an induction...
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Sensorless field oriented control for five-phase induction motors with third harmonic injection and fault insensitive feature
PublikacjaThe paper presents a solution for sensorless field oriented control (FOC) system for five-phase induction motors with improved rotor flux pattern. In order to obtain the advantages of a third harmonic injection with a quasi-trapezoidal flux shape, two vector models, α1–β1 and α3–β3, were transformed into d1– q1, d3– q3 rotating frames, which correlate to the 1st and 3rd harmonic plane respectively. A linearization approach of the...
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Structured deformation of granular material in the state of active earth pressure
PublikacjaThe paper focuses on the ability of granular materials to undergo structured deformation by analysing the data from the retaining wall model tests and discrete element simulations. The structured deformation means the movement of a granular material which produces a stable, regular pattern of multiple shear bands. The paper's primary purpose is to study this kind of deformation for the selected data representing the state of active...
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Novel Investigation of Higher Order Spectral Technologies for Fault Diagnosis of Motor-Based Rotating Machinery
PublikacjaIn the last decade, research centered around the fault diagnosis of rotating machinery using non-contact techniques has been significantly on the rise. For the first time worldwide, innovative techniques for the diagnosis of rotating machinery, based on electrical motors, including generic, nonlinear, higher-order cross-correlations of spectral moduli of the third and fourth order (CCSM3 and CCSM4, respectively), have been comprehensively...
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Water currents in Głębinka Passage in late spring of 1975
Dane BadawczeData set contains the results of the field measurements of horizontal water currents carried out in the Głębinka Passage in Puck Bay (Southern Baltic, Poland) in 1975 by Department of Physical Oceanography (Institute Oceanography, University of Gdańsk). Głębinka Passage is a narrow strait playing crucial role in water exchange between shallow and deep...
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Signature of Oxide-Ion Conduction in Alkaline-Earth-Metal-Doped Y3GaO6
PublikacjaWe have studied alkaline-earth-metal-doped Y3GaO6 as a new family of oxide-ion conductor. Solid solutions of Y3GaO6 and 2% −Ca2+-, −Sr2+-, and −Ba2+-doped Y3GaO6, i.e., Y(3−0.06)M0.06GaO6−δ (M = Ca2+, Sr2+, and Ba2+), were prepared via a conventional solid-state reaction route. X-ray Rietveld refined diffractograms of all the compositions showed the formation of an orthorhombic structure having the Cmc21 space group. Scanning electron...
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Apparent molar volumes and compressibilities of alkaline earth metal ions in methanol and dimethylsulfoxide
PublikacjaTemperature dependencies of density of magnesium (II), calcium (II), strontium (II), barium (II) perchlorates as well as beryllium (II), and sodium trifluoromethanesulfonates in methanol and dimethylsulfoxide have been determined over the composition range studied. From density data the apparent molar volumes and partial molar volumes of the salts at infinite dilution as well as the expansibilities have been evaluated. The apparent...
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Fault detection and diagnostics of complex dynamic systems using Gaussian Process Models - nuclear power plant case study
PublikacjaThe article examines the use of Gaussian Process Models to simulate the dynamic processes of a Pressurized Water nuclear Reactor for fault detection and diagnostics. The paper illustrates the potential of Gaussian Process Models as a tool for monitoring and predicting various fault conditions in Pressurized Water nuclear Reactor power plants, including reactor coolant flow and temperature variations, deviations from nominal working...
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Earth
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Sensorless algorithm for sustaining controllability of IPMSM drive in electric vehicle after resolver fault
PublikacjaThis paper presents a sensorless algorithm designated for the emergency control of an interior permanent magnet synchronous motor (IPMSM) drive in electric or hybrid vehicle. The algorithm is based on analysing the derivatives of motor phase currents measured over the duration of particular inverter states. The method is computationally simple and does not require additional hardware since the derivatives are measured indirectly....
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GeoPlanet: Earth and Planetary Sciences
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Fault Loop Impedance Measurement in Circuits Fed by UPS and Principle of Safety Protection
PublikacjaThis paper indicates a significant problem of uncertainty of fault loop impedance (FLI) measurement in circuits powered from uninterruptible power supply (UPS) (double-conversion AC-DC-AC). The correctly determined value of this impedance, related to the short-circuit current disconnection time and to the reference value, is one of the most important elements that determines the approval of an electrical installation and its receivers...
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Discrete measurement of fault-arc velocity
PublikacjaOpisano metodę dyskretnego pomiaru prędkości jednofazowego łuku awaryjnego poruszającego się w płaskim, poziomym układzie szyn. Badania przeprowadzono za pomocą punktowych czujników optycznych rozmieszczonych równomiernie wzdłuż szyn. Podano opis układu, jego charakterystykę, wpływ obszaru zjonizowanego na uzyskiwane wyniki i zależności między obserwowanymi wielkościami.
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Fault detection in the marine engine using a support vector data description method
PublikacjaFast detection and correct diagnosis of any engine condition changes are essential elements of safety andenvironmental protection. Many diagnostic algorithms significantly improve the detection of malfunctions.Studies on diagnostic methods are rarely reported and even less implemented in the marine engine industry.To fill this gap, this paper presents the Support Vector Data Description (SVDD) method as applied to thefault detection...
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Thermally stimulated currents in disordered solids at step heating
PublikacjaW pracy podano rezultaty badań teoretycznych prądów termicznie stymulowanych (TSC) w nieuporządkowanych ciałach stałych, wywołanych krokowym ogrzewaniem próbki. Rozszerzono metodę Gobrechta-Hofmanna analizy TSC na przypadek znaczącego powtórnego pułapkowania nośników. Rozpatrzono TSC mierzone w próbkach o konfiguracji koplanarnej i kanapkowej. Głównymi czynnikami ograniczającymi TSC są wówczas odpowiednio: rekombinacja monomolekularna...
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Comprehensive distortion compensation of grid-connected inverter currents
PublikacjaThe paper presents a comprehensive approach to the compensation of phase current distortion of grid-connected power inverters. Four different sources of current distortion are addressed: imperfect grid synchronization caused by the distortion in the grid voltages, voltage fluctuations in the dc link, time delays in the estimation of grid voltages, and the distortion of inverter output voltages due to dead-time effects and related...
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Currents and photocurrents in organic materials determined by the interface phenomena
PublikacjaW pracy analizowany jest wpływ złącza materiał-elektroda na prądy i fotoprądy. W szczególności dyskutowane są mechanizmy iniekcji, fotogeneracji oraz transportu nośników ładunku. Rozważania teoretyczne uzupełniają wyniki badań doświadczalnych zarówno własne jak i literaturowe.
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Efficiency of hybrid equipment combining operations of surface hardening by high frequency currents and abrasive grinding
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Data-driven models for fault detection using kernel pca:a water distribution system case study
PublikacjaKernel Principal Component Analysis (KPCA), an example of machine learning, can be considered a non-linear extension of the PCA method. While various applications of KPCA are known, this paper explores the possibility to use it for building a data-driven model of a non-linear system-the water distribution system of the Chojnice town (Poland). This model is utilised for fault detection with the emphasis on water leakage detection....
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PLoS Currents-Tree of Life
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PROPERTIES OF DOPED ALKALINE-EARTH STANNATES
PublikacjaThe lanthanum doped barium stannate properties are investigated in this work. Including electrical and microstructural properties.
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Speed sensorless ac drive with inverter output filter and fault detection using load torque signal
PublikacjaIn this paper, a sensorless induction motor (IM) drive using speed observer system is presented. The system includes load torque computation for gear fault detection. Nonlinear control method is adopted for controlling the motor over a wide speed range. An LC filter for smoothing current and voltage waveforms is used at the output of the voltage inverter. The use of filter imposes more building of the used observer to avoid using...
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Phytoextraction and recovery of rare earth elements using willow (Salix spp.)
PublikacjaSoil and water contaminations are caused by rare earth elements (REEs) due to mining and industrial activities, that threaten the ecosystem and human health. Therefore, phytoremediation methods need to be developed to overcome this problem. To date, little research has been conducted concerning the phytoremediation potential of Salix for REEs. In this study, two Salix species (Salix myrsinifolia and Salix schwerinii) and two Salix...
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Fault diagnosis of marine 4-stroke diesel engines using a one-vs-one extreme learning ensemble
PublikacjaThis paper proposes a novel approach for intelligent fault diagnosis for stroke Diesel marine engines, which are commonly used in on-road and marine transportation. The safety and reliability of a ship's work rely strongly on the performance of such an engine; therefore, early detection of any type of failure that affects the engine is of crucial importance. Automatic diagnostic systems are of special importance because they can...
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Speed Sensorless AC Drive with Inverter LC Filter and Fault Detection Using Load Torque Signal
PublikacjaThe industrial development in recent years has seen a major increase in the use of induction motors, whereby the cost has to be as low as possible and the lifetime as long as possible. To follow up this desire, investigations in this area have become very intense. For that reason, this paper presents a solution for driving an induction motor and simultaneous fault detection with no need for additional sensors. In order to achieve...
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Fault detection in measuring systems of power plants
PublikacjaThis paper describes possibility of forming diagnostic relations based on application of the artifical neural networks (ANNs), intended for the identifying of degradation of measuring instruments used in developed power systems. As an example a steam turbine high-power plant was used. And, simulative calculations were applied to forming diagnostic neural relations. Both degradation of the measuring instruments and simultaneously...
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Tool support for ECSDM fault tree methodology
PublikacjaExtended Common Safety Description Model (ECSDM) jest językiem do formalnej specyfikacji systemów związanych z bezpieczeństwem oraz ich komponentów. Język ten zawiera konstrukcje umożliwiające specyfikację zależności czasowych. Może on zostać użyty w analizie drzew błędów, aby uzyskać jednoznaczną specyfikację hazardów w sytuacji, gdy są one uzależnione od związków czasowych pomiędzy przyczynami. Artykuł opisuje narzędzie wytworzone...
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Grinding specifics of plasma coatings melted with high-frequency currents
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Measure small currents without adding resistive insertion loss
PublikacjaFloating current to voltage converter can be inserted in-line with no voltage drop and no need for a ground reference.
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Multipath routing for quality of service differentiation and network capacity optimization in broadband low-earth orbit systems
PublikacjaThis paper shows the importance of employing multiple different paths for routing in Inter-Satellite Link (ISL) networks in broadband Low-Earth Orbit (LEO) satellite systems. A theoretical analysis is presented and a routing concept is proposed to demonstrate three facts that make multipath routing especially important in broadband LEO networks: (1) differences in the propagation delays have a much greater impact on end-to-end...
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Optical and photocatalytic properties of rare earth metal-modified ZnO quantum dots
PublikacjaA series of novel ZnO quantum dots modified with rare earth metals was successfully prepared by a simple sol-gel approach. The effects of types (Eu, Er, Tb, Yb, Ho, La) and amounts (from 0.09 to 0.45 mmol) of lanthanides on the optical properties, structural characterization and photocatalytic activity of ZnO/RE QDs were systematically investigated. The X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform...
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Rare-earth elements in human colostrum milk
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Lattice dynamics of the rare-earth element samarium
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IOP Conference Series: Earth and Environmental Science
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Extreme bottom velocities induced by wind wave and currents in the Gulf of Gdańsk
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Rip currents in the southern Baltic Sea multi-bar nearshore zone
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Thermally stimulated currents in amorphous solids due to complex heating regimes
PublikacjaPodano opis teoretyczny prądów termicznie stymulowanych w ciałach amorficznych. Dokonano rozszerzenia istniejących wzorów przybliżonych na przypadki opóźnionego i krokowego ogrzewania próbki. Otrzymane wyrażenia zweryfikowano za pomocą obliczeń numerycznych dla przypadku wykładniczego rozkładu pułapek.
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Earthing effective length for low and high amplitudes of lightning impulse currents
PublikacjaUziemienia w systemie elektroenergetycznym mogą być bardzo rozległe, zwłaszcza ze względu powszechne stosowanie połączeń ekwipotencjalizacyjnych. Ocena tak rozległych systemów z punktu widzenia ich przydatności do celów ochrony odgromowej jest dość trudna, ponieważ tylko część takiego rozległego systemu bierze udział w rozpraszaniu prądu piorunowego w gruncie. Ta część uziomu jest nazywana jego długością efektywną. W pracy zamieszczono...
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Results of investigations of the fault arc in L. V. Switchgears
PublikacjaOmówiono wyniki badań eksperymentalnych wyłączania 3 fazowych zwarć łukowych w rozdzielnicach niskonapięciowych za pomocą aparatów umieszczanych jedynie w środkowej fazie płaskiego układu szyn zbiorczych. ...
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Measurements of the rms currents in two phases in a ship power station with two generators operating in parallel
Dane BadawczeThe presented dataset is part of research focusing on the assessment of metrological properties of the instrument, Estimator/Analyzer (E/A v.2), developed and made at the Faculty of Electrical Engineering, Department of Marine Electrical Power Engineering of Gdynia Maritime University. The attached dataset contains processed data, expressing the rms...
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Earth Interactions
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Solid Earth
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Planet Earth
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All Earth
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One Earth
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Monometallic nanoparticles decorated and rare earth ions doped KTaO3/K2Ta2O6 photocatalysts with enhanced pollutant decomposition and improved H2 generation
PublikacjaNew, monometallic nanoparticles (MNPs) decorated surface and rare earth (RE) ions doped lattice of perovskite-type (KTaO3)/pyrochlore-type (K2Ta2O6) photocatalysts were successfully prepared by facile hydrothermal incorporation of RE ions into KTaO3/K2Ta2O6 lattices followed by photodeposition of MNPs. The impact of noble metal type (MNPs = Au, Pt, Rh) and rare earth dopant type (RE = Er, Pr) on the physicochemical properties correlated...
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Visible light activity of rare earth metal doped (Er3+, Yb3+ or Er3+/Yb3+) titania photocatalysts
PublikacjaA series of Er3+-TiO2, Yb3+-TiO2 and Er3+/Yb3+-TiO2 photocatalysts were obtained via sol-gel method, using rare earth metal (RE) precursor ranging from 0.25 to 10 mol%. The experiments demonstrated that phenol in aqueous solutions was successfully degraded under visible light (> 450 nm) using RE3+-TiO2. The as-prepared samples were characterized by X-ray diffraction (XRD), X-ray photoelectron emission spectroscopy (XPS), UV-Vis...
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Characterization of diatomaceous earth coated with nitrated asphaltenes as superior adsorbent for removal of VOCs from gas phase in fixed bed column
PublikacjaAsphaltenes isolated from bitumen possess unusual adsorption characteristics that can be further enhanced by chemical modifications to promote interactions with VOCs’. Herein, nitrated asphaltenes are used as an active layer coated on a surface of a diatomaceous earth, in order to prepare an efficient adsorbent (AsfNitro). Breakthrough experiments with benzene, pyridine, and 1-nitropropane revealed significant increase in adsorption...
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Effects in stator currents of cage motors due to saturation of main magnetic circuit
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