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Induced sheath voltages in 110 kV power cables – case study
PublikacjaThis paper considers electric shock hazard due to induced sheath voltages in 110 kV power cables. The purpose of this paper is to find an optimal configuration of the power cable system, taking into account electric shock hazard and ability of the system to transfer maximal power. A computer simulations on a computer model of the local power system, comprising high voltage power cables, were carried out. This model enables to analyse...
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Hydroxyapatite deposition on the laser modified Ti13Nb13Zr alloy
PublikacjaThe Ti13Nb13Zr alloy was subjected to laser modification with the Nd:YAG laser provided that such treatment would increase the surface roughness followed improved adhesion of hydroxyapatite (HAp) coatings The hydroxyapatite was deposited by electrophoretic method in suspension of 0.5 g HA powder and 100 ml ethyl alcohol. The deposition was carried out for 10 min at 10 V voltage followed by drying at room temperature for 24 h and...
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Low-frequency tripping characteristics of residual current devices
PublikacjaFast development of various types of converters makes their utilization in industry and in domestic installations very common. Due to converters, an earth fault current waveform in modern circuits can be distorted or its frequency can be different than 50/60 Hz. Frequency of earth fault (residual) current influences tripping of residual current devices which are widely used in low voltage systems. This paper presents the behaviour...
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LabVIEW-based intelligent system of protection against electric shock for photovoltaic installations
PublikacjaEvaluation of shock hazard in installations with photovoltaic sources of energy is more complicated than in a conventional low voltage system. In case of earth fault in photovoltaic generators, that are connected to the AC power public grid, a composite waveform of earth fault current in the installation may occur. For composite waveforms, the safety criteria should be modified. The paper considers the effect of the composite waveforms...
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The determinants of morphology and properties of the nanohydroxyapatite coating deposited on the Ti13Zr13Nb alloy by electrophoretic techniqe
PublikacjaThe titanium and its alloys belong at present to the most preferred and commonly applied biomaterials for load- bearing implants. The surfaces of biomaterials are subjected to modification, including the hydroxyapatite coatings deposited in order to ensure corrosion resistance and better joining between an implant and a bone through the possibility of ingrowth bone into the coating. In this paper, the morphology and properties...
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The impact of material degradation on the resistance and reliability of truss structures
PublikacjaThe paper analyses limit load-carrying capacity and buckling load of truss towers used to support high voltage power lines. The analysed typical structure was subjected to characteristic loads and their combinations. The results were applied to assess structural resistance with regard to steel corrosion in the long-term operation. The extent of structural deterioration was assessed due to Young's modulus decrement in the course...
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Low speed permanent magnet synchronous generator for vertical axis wind turbine
PublikacjaThe paper presents design process and tests of a prototype low speed permanent magnet synchronous generator (PMSG) dedicated for the innovative vertical-axis wind turbine. The rated data of the designed generator are following: power - 15 kVA, voltage - 400 V (Y), rotation speed - 93.75 rpm. The design assumptions, chosen results of the design process and experimental tests of the prototype PMSG are presented. The considered PMSG...
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Low-frequency noise in ZrS3 van der Waals semiconductor nanoribbons
PublikacjaWe report the results of the investigation of low-frequency electronic noise in ZrS3 van der Waals semiconductor nanoribbons. The test structures were of the back-gated field-effect-transistor type with a normally off n-channel and an on-to-off ratio of up to four orders of magnitude. The current–voltage transfer characteristics revealed significant hysteresis owing to the presence of deep levels. The noise in ZrS3 nanoribbons...
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Samotestowanie toru analogowego ze wzmacniaczem w pełni różnicowym w elektronicznych systemach wbudowanych sterowanych mikrokontrole-rami
PublikacjaPrzedstawiono nową metodę samotestowania toru analogowego opartego na wzmacniaczu w pełni różnicowym w elektronicznych systemach wbu-dowanych sterowanych mikrokontrolerami. Bazuje ona na nowej metodzie diagnostycznej opartej na przekształceniu transformującym próbki odpo-wiedzi czasowej badanej części analogowej na pobudzenie "ujemnym" impulsem prostokątnym na wejściu Vocm na krzywe identyfikacyjne w przestrzeni pomiarowej. Metoda...
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Diagnostyka off-line stanu izolacji uzwojeń silników 6 kV z wykorzystaniem obrazowania akustycznego wyładowań niezupełnych
PublikacjaW zakładach przemysłowych, w których kluczowe procesy produkcyjne są realizowane z wykorzystaniem silników średniego napięcia, dla których diagnostyka izolacji uzwojeń ma istotne znaczenie. W tym celu wykonuje się ocenę porównawczą wyników pomiarów wyładowań niezupełnych (WNZ) wykonywanych dla jednostek tego samego typu, a jej skuteczność w znacznej mierze wynika z wieloletniego doświadczenia diagnosty. Dla opracowania wyników...
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Wielopoziomowe przekształtniki średniego napięcia (SN) o budowie modułowej
PublikacjaW artykule omówiono wybrane zagadnienia dotyczące zastosowań wielopoziomowych przekształtników średniego napięcia (SN) w układach napędowych o regulowanej prędkości, zwłaszcza w układach z izolacją od sieci zasilającej. W opracowanym przekształtniku zastosowano izolację galwaniczną od sieci zrealizowaną za pomocą izolowanych przetwornic dc-dc z transformatorami wysokiej częstotliwości (> 5 kHz). Przedstawiono zarejestrowane przebiegi...
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Algorytmy wyodrębniania składowych symetrycznych sygnału pomiarowego napięcia w przypadku asymetrii sieci trójfazowej
PublikacjaW artykule zaprezentowano działanie wybranych algorytmów wykorzystywanych do wyodrębniania składowych symetrycznych z sygnałów pomiarowych napięcia lub prądu w przypadku wystąpienia asymetrii trójfazowej sieci elektroenergetycznej. Weryfikacji działania algorytmów dokonano na podstawie badań symulacyjnych i laboratoryjnych w układzie w którym jako odbiornik zastosowano stojan maszyny asynchronicznej pierścieniowej. Określono wpływ...
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Observation value analysis - integral part of Bayesian diagnostics
PublikacjaDetailed subject of the research is to analyse the value of the observation, which is a part of preposterior analysis. For the presented network, the main objective was to determine, conducting of which of three tests is the most valuable from the perspective of determining possible need or possibility to omission expensive technical expertise. The main advantage of preposterior analysis is answering the question which of the considered...
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Dynamic state assessment of the water turbine with the power of 600 kW
PublikacjaThe article discusses the results of experimental studies to assess the dynamic state of the turbine set with the Kaplan turbine. The dynamic assessment was made on the basis of appropriate standards, based on the measurement results of selected parameters of vibration, which have been measured for several states of the machine load. In addition, we attempted to identify the causes of the increased vibration levels based on the...
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Rational Use of Primary Energy in Single-Family Residential Houses
PublikacjaThis work presents results of the primary energy use for heating residential single-family house. Analysis includes domestic hot water system (DHW) and heating, ventilation and air condition system (HVAC). During researches the conventional and alternative energy sources (natural gas, biomass, fuel oil, bituminous coal, lignite or electric energy obtained from electric power system – EPS) were used in DHW and HVAC systems. Furthermore...
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A NOVEL CONCEPT OF H2/O2 STEAM GENERATOR
PublikacjaThis paper presents an idea of hydrogen utilization to steam generation to drive a turbine and produce electricity or to supply a condenser as an element of heating system. Electrolysis process is considered as a source of hydrogen as well as oxygen. Hydrogen combustion with a stoichiometric ratio of pure oxygen produces steam at very high temperature. Steam temperature can be controlled by mixing the generated steam with liquid...
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A novel concept of H2/O2 steam generator
PublikacjaThis paper presents an idea of hydrogen utilization to steam generation to drive a turbine and produce electricity or to supply a condenser as an element of a heating system. Electrolysis process is considered as a source of hydrogen as well as oxygen. Hydrogen combustion with a stoichiometric ratio of pure oxygen produces steam at very high temperature. Steam temperature can be controlled by mixing the generated steam with liquid...
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Performance of the PVT solar collector operated with water-Al2O3 nanofluid
PublikacjaAn experimental investigation of the hybrid module photovoltaic panel -solar collector (PVT) cooled by water-Al2O3 nanofluids has been conducted. The weight fractions of the nanoparticles were 1% and 3%. Thermal efficiency, power efficiency and overall efficiency have been determined for artificial source of light and sunlight. No noticeable effect of the nanoparticle concentration on the overall efficiency of the PVT module has...
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PERFORMANCE OF THE PVT SOLAR COLLECTOR OPERATED WITH WATER –AL2O3 NANOFLUID
PublikacjaAn experimental investigation of the hybrid module photovoltaic panel -solar collector (PVT) cooled by water-Al2O3 nanofluids has been conducted. The weight fractions of the nanoparticles were 1% and 3%. Thermal efficiency, power efficiency and overall efficiency have been determined for artificial source of light and sunlight. No noticeable effect of the nanoparticle concentration on the overall efficiency of the PVT module has...
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Metody oczyszczania odcieków z procesów przeróbki osadów w komorach fermentacji
PublikacjaOdcieki z beztlenowych procesów przeróbki osadu w komorach fermentacji (tzw. wody poosadowe) są istotnym źródłem azotu dopływającego do części biologicznej oczyszczalni ścieków. Odpowiednie oczyszczanie tych wód może więc, w bardzo istotny sposób wpłynąć na warunki eksploatacji oczyszczalni. Konwencjonalny proces usuwania amoniaku za pomocą dwóch faz, tj. nitryfikacji i denitryfikacji, są coraz częściej zastępowane przez jednoetapowy...
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Nowoczesne układy przekształtników wielopoziomowych do zasilania statków z lądu
PublikacjaW artykule poruszono tematykę zasilania statków zacumowanych w porcie z lądowej sieci elektroenergetycznej poprzez wykorzystanie nowoczesnych konstrukcji przekształtników energoelektronicznych. W treści pracy zaprezentowano porównanie dwóch topologii wysokonapięciowych przekształtników wielopoziomowych. Porównano konstrukcje przekształtników z klasycznym transformatorem wielouzwojeniowym oraz z transformatorami wysokoczęstotliwościowymi.
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Li nucleation on the graphite anode under potential control in Li-ion batteries
PublikacjaApplication of Li-ion batteries in electric vehicles requires improved safety, increased lifetime and high charging rates. One of the most commonly used intercalation anode material for Li-ion batteries, graphite, is vulnerable to Li nucleation, a side reaction which competes with the intercalation process and leads to loss of reversible capacity of the battery, ageing and short-circuits. In this study, we deploy a combined grand...
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Wpływ uwarunkowań rzeczywistych na pracę równoległego filtru aktywnego sterowanego ze sprzężeniem od prądu zasilającego
PublikacjaW artykule przedstawiono wpływ uwarunkowań rzeczywistych na pracę równoległego filtru aktywnego i zdolność kompensacji prądów harmonicznych. Zbadano wpływ opóźnień czasowych wynikających z implementacji cyfrowej sterowania, wpływ impedancji zwarciowej sieci zasilającej oraz błędów generowania napięcia przekształtnika na jakość kompensacji filtru. Badania symulacyjne przeprowadzono dla trzech układów sterowania: otwartego, zamkniętego...
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Szkoła systemu Linux
PublikacjaKsiążka ''Szkoła systemu Linux'' wprowadza czytelnika w świat oprogramowania typu open source. Przedstawione zostały liczne programy, które umożliwiają między innymi zarządzanie danymi, pisanie i drukowanie dokumentów czy korzystanie z sieci. Za pomocą ksiązki można się nauczyć używania środowiska graficznego oraz wiersza poleceń. Opisano również działanie systemów operacyjnych, w tym Linux. Na płycie dołączonej do książki znajduje...
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Technical evaluation of marine auxiliary diesel engine on the basis of parameters synchronous generator
PublikacjaThe article presents a method for evaluating the technical condition of selected structural elements of the reciprocating internal combustion engine driving a synchronous generator. Th results of measurements of the electric generator parameters are the diagnostic information source. On this basis it is possible to determine the instantaneous angular speed marine engine crankshaft which, in turn, is the basis for reasoning about...
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Adapting the pinch point analysis to improve the ORC design process
PublikacjaPinch point analysis can be adapted so as to assist in the early stages of designing the ORC systems. Typically used in determining the working parameters of heat exchangers, it can be employed to improve the heat fitting between the source of heat and the working fluids of the ORC system. To attain the parametric match, an algorithm was built enabling quick estimation of the possible heat reception by the specific working fluid....
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A new time-frequency detection method of stray current field interferenceon metal structures.
PublikacjaA new detection method has been presented of stray current field interference on underground metal structures. The method employs short time Fourier transformation (STFT). This method of analysis allows determination of signal spectral power density changes (e.g., structure potential) in the function of time. In the paper results have been presented of total time–frequency analysis of a pipeline potential in a stray current field...
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Nowe technologie teleinformatyczne w realizacji systemów zdalnej edukacji.
PublikacjaArtykuł dokonuje analizy możliwości i efektywności zastosowania technologii internetowych we wdrażanych obecnie zaawansowanych systemach zdalnej edukacji różnych typów. Kolejną część opracowania poświęcono analizie dalszych możliwości rozwoju tego rodzaju produktów w oparciu o standard SCORM i zastosowane tam powiązanie systemów edukacji elektronicznej z technologiami internetowymi. Przykładem mogą być tu prace nad rozszerzeniem...
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Towards semantic-rich word embeddings
PublikacjaIn recent years, word embeddings have been shown to improve the performance in NLP tasks such as syntactic parsing or sentiment analysis. While useful, they are problematic in representing ambiguous words with multiple meanings, since they keep a single representation for each word in the vocabulary. Constructing separate embeddings for meanings of ambiguous words could be useful for solving the Word Sense Disambiguation (WSD)...
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Porous Phantoms Mimicking Tissues – Investigation of Optical Parameter Stability Over Time
PublikacjaIn terms of optical parameters, optical phantoms can now replace live tissues and be used to validate optical measurement methods. Therefore, whether these parameters would be maintained after storage for 6 months was examined. The absorption and scattering coefficients were obtained from the measured transmittance and reflectance measurements taken 6 months apart and then compared. All of the measurements were conducted using...
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Airborne wear particle emission from train brake friction materials with different contents of steel and copper fibres
PublikacjaThis study investigated the influence of the amount of steel and copper fibres in a train brake friction material on the tribological performance, emission intensity and characteristics of airborne wear particles. The particles were generated on a pin-on-disc tribometer under controlled friction and environmental conditions. It was found that the steel fibre results in a more intensive emission of 0.3–10 μm particles compared to...
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An algorithmic approach to estimating the minimal number of periodic points for smooth self-maps of simply-connected manifolds
PublikacjaFor a given self-map f of M, a closed smooth connected and simply-connected manifold of dimension m 4, we provide an algorithm for estimating the values of the topological invariant D^m_r [f], which equals the minimal number of r-periodic points in the smooth homotopy class of f. Our results are based on the combinatorial scheme for computing D^m_r [f] introduced by G. Graff and J. Jezierski [J. Fixed Point Theory Appl. 13 (2013),...
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AI in the creation of the satellite maps
PublikacjaSatellite and aerial imagery acquisition is a very useful source of information for remote monitoring of the Earth’s surface. Modern satellite and aerial systems provide data about the details of the site topography, its characteristics due to different criteria (type of terrain, vegetation cover, soil type and moisture content), or even information about emergency situations or disasters. The paper proposes and discusses the process...
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A Reputation Scheme to Discourage Selfish QoS Manipulation in Two-Hop Wireless Relay Networks
PublikacjaIn wireless networks, stations can improve their received quality of service (QoS) by handling packets of source flows with higher priority. Additionally, in cooperative relay networks, the relays can handle transit flows with lower priority. We use game theory to model a two-hop relay network where each of the two involved stations can commit such selfish QoS manipulation. We design and evaluate a reputation-based incentive scheme...
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The influence of the development of private air communication on the architecture and urban planning of the 21st century
PublikacjaIn the first part, the article describes the stages of the development of gyroplanes and the influence of wartime policy on the interest in light aircraft. Also presented are links and the possibilities of using gyroplanes in various sectors of the economy. The authors, based on source texts, present the current position of the aviation industry in the Polish economy and attempt to diagnose its development capabilities. As a result,...
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Semantic technologies based method of collection, processing and sharing information along food chain
PublikacjaIn the paper the method of collecting, processing and sharing information along food chain is presented. Innovative features of that method result from advantages of data engineering based on semantic technologies. The source to build ontology are standards and regulations related to food production, and data collected in databases owned by food chain participants. It allows food chain information resources can be represented in...
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Recurrent bowel-blood translocations of Escherichia coli with the unique virulence characteristics over three-year period in the patient with acute myeloid leukaemia – case report
PublikacjaIn patients with haematological malignancies, the bowel remains the main source of Escherichia coli bloodstream infections. We present the clinical example of recurrent bowel-blood translocations of E. coli with the unique virulence characteristics in a 55-year-old male with the diagnosis of acute myeloid leukaemia. The virulent factors profile of examined strains confirmed that the co-existence of genes papC, sfa, usp and cnf1,...
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Acoustic Heating Produced in the Thermoviscous Flow of a Shear-Thinning Fluid
PublikacjaThis study is devoted to the instantaneous acoustic heating of a shear-thinningfluid. Apparent viscosity of a shear-thinning fluid depends on the shear rate. Thatfeature distinguishes it from a viscous Newtonian fluid. The special linear combi-nation of conservation equations in the differential form makes it possible to derivedynamic equations governing both the sound and non-wave entropy mode inducedin the field of sound. These...
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Analiza ograniczeń technologicznych systemów lokalizacji inercyjnej
PublikacjaW artykule opisano kluczowe ograniczenia technologiczne zmniejszające dokładność inercyjnych systemów lokalizacyjnych. Każdy z czynników został przedstawiony w kontekście swego źródła oraz wpływu na proces lokalizacyjny. Dodatkowo w artykule zawarto opis metod kompensacji błędów występujących w procesie lokalizacji inercyjnej. W treści artykułu analizie poddano rozwiązania obecne w systemach lokalizacji inercyjnej dla wolno poruszających...
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Using water sources extent during inundation as a reliable predictor for vegetation zonation in a natural wetland floodplain
PublikacjaDistinctive zones of inundation water during floods were shown to originate from different sources in some major floodplains around the world. Recent research showed that the zonation of water in rivers and floodplains is related to vegetation patterns. In spite of this, water source zones were not used for vegetation modeling due to difficulties in their delineation. In this study, we used simulation results of a fully-coupled...
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Collection Efficiency in Narrow Electrostatic Precipitators with a Longitudinal or Transverse Wire Electrode
PublikacjaRecently narrow electrostatic precipitators (ESPs) have become a subject of interest because of their possible application in diesel engine exhaust systems. In this work, results of particle collection efficiency measurements in narrow electrostatic precipitators for negative and positive dc voltage polarity are presented. The ESP usedin this work was a parallelepiped equipped with wire discharge electrode and two collecting plate-electrodes....
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Nonlinear Model of Synchronous Generator for Autonomous Electrical Power Systems Analysis
PublikacjaThis paper presents the nonlinear lookup table model for synchronous generator (SG) analysis. The saturation effects of the SG magnetic circuit have been considered. The saturated characteristic of the SG magnetic circuit are based on the open circuit saturation curve for magnetizing inductances. The model has been implemented into the Synopsys/Saber software using the MAST modelling language. To implement the no-load voltage characteristic...
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Preliminary investigations of effect of conditions of FCAW process on diffusible hydrogen content in deposited metal
PublikacjaOne of the types of hydrogen degradation of steel welded joints is cold cracking. The direct cause of the formation of cold cracks is simultaneous presence of hydrogen, residual stresses and brittle structure. The way of preventing the occurring of degradation is to eliminate at least one of these factors. Practice has shown that the best solution is to control the amount of hydrogen in deposited metal. In this paper the state...
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Nanotubular oxide layers and hydroxyapatite coatings on ‘Ti–13Zr–13Nb’ alloy
PublikacjaThe presented research was aimed to determine the mechanical properties of the nanotubular oxide layer covered with hydroxyapatite coating. The Ti–13Zr–13Nb alloy was oxidised in 1M phosphoric acid with an addition of 0?5% HF for HF solution at 20 V voltage. The electrochemically assisted deposition of hydroxyapatite was performed at cyclic polarisation in NH4H2PO4 and CaCl2 solution at 80uC. The mechanical properties were determined...
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The influence of the motor filtrers on harmonic current emmision in the pro-ective connection of drive systems.
PublikacjaThis paper contains detailed analysis of currents in protective wire in engine supplied from frequency converter without any external filters added. It was found that the peak value of current in protective conductor of engine was about 1500 mA at frequencies 5 Hz 50 Hz. In the continuation of research the dU/dt type motor filter and the sinusoidal filter were tested. It was found that the current in protective wire decreased...
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Production and Properties of the Porous Layer Obtained by the Electrochemical Method on the Surface of Austenitic Steel
Publikacja: The growing demand for implants has seen increasing interest in the introduction of new technologies and surface modification methods of metal biomaterials. This research aimed to produce and characterize a porous layer grown on austenitic stainless steel 316L, obtained via the anodization process near the micro-arc oxidation, i.e., low voltage micro-arc oxidation (LVMAO). The discussed layer significantly influences the properties...
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Effect of solar radiation on current-carrying capacity of PVC-insulated power cables – the numerical point of view
PublikacjaPower cables are usually buried in the soil, which results in their relatively high current-carrying capacity. However, there are cases in which the starting/final section of a cable line runs along a pole of an overhead power line. Power cables can be directly exposed to solar radiation then, and this negatively influences their current-carrying capacity as well as estimated life of the cables’ insulation. An analysis of thermal...
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Impedance monitoring of fuel cell stacks
PublikacjaThis paper presents an innovative, electrochemical impedance method for monitoring of electrochemical behaviour of a multi-cell, direct methanol fuel cell (DMFC) device. This method not only provides classical voltage changes at successive cells but also allows their detailed impedance behaviour to be presented. Impedance characteristics of individual cells within a fuel cell stack (depending on actual operating conditions) are...
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RCDs Tripping in the Range from DC to AC 50 kHz for Slowly Rising Residual Current
PublikacjaThe wide use of power electronic converters means that in many low-voltage systems earth fault currents containing components from DC to AC of various frequencies have to be taken into account. Due to the tendency to increase the modulation frequency in converters, components of higher frequencies may be in the order of several tens of kilohertz. Therefore, it is very important to verify the behavior of devices for protection against...
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Comparative Study of Integer and Non-Integer Order Models of Synchronous Generator
PublikacjaThis article presents a comparison between integer and non-integer order modelling of a synchronous generator, in the frequency domain as well as in the time domain. The classical integer order model was compared to one containing half -order systems. The half-order systems are represented in a Park d-q axis equivalent circuit as impedances modelled by half-order transmittances. Using a direct method based on the approximation...