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Vaccination Against Measles, Mumps, and Rubella in the Light of Current Epidemic Threats: Unjustified Postponement
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Sensorless IPMSM drive with rotor position estimator based on analysis of phase current derivatives
PublikacjaThis paper describes a sensorless Interior Permanent Magnet Synchronous Motor (IPMSM) drive designed for traction applications. Wide-speed sensorless operation is provided with the use of three methods of rotor position estimation designed for: a standstill, low- and high-speed range. The paper focuses on the high-speed estimation algorithm. The estimator uses the derivatives of motor phase currentsresulting from PWM modulation...
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How Important Is Research on Pollution Levels in Antarctica? Historical Approach, Difficulties and Current Trends
PublikacjaDespite the fact that Antarctica is a continent notably free from large negative impact of human activities, literature data can be the basis for concluding that this is not an area free from anthropogenic pollutants. Pollutants, which are identified in various elements of the environment of Antarctica, are mostly connected with long-range atmospheric transport (LRAT) and deposition in this area. The study presents: a historical...
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Current-based higher-order spectral covariance as a bearing diagnostic feature for induction motors
PublikacjaConducting the diagnosis of induction motors remotely by analyzing the supply current is an attractive prospect with the lack of access to the engine. Currently, there is no solution, based on analysis of the current, the credibility of which would allow its use in industry. The statistics of bearing failures in induction motors indicate that they constitute more than 40% of induction motor damage, therefore, bearing diagnosis...
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The effect of current signal filtering method on the value of cutting power while sawing wood
PublikacjaThe goal of this work was to investigate an effect of various signal pre-processings on the outline of the electrical power curve and its influence on the measured cutting force estimation. Two signal processing methods were selected for the needs of the experiment, including digital filter and wavelet transform. The filter used was Butterworth, 3rd order band-stop with the cut-out band from 45 Hz to 55 Hz. The second approach...
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Multiple output second-generation current conveyor utilizing high frequency output stage
PublikacjaIn this paper a multiple output second-generation current conveyor (MOCCII) is presented. The main advantage of the proposed general circuit architecture over a typical structure, well known in the literature, is the use of a high passband multiple output current mplifier block instead of cascaded current mirrors. It gives similar frequency responses for all the outputs of the current conveyor and also maintains simplicity of the...
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CFD-based evaluation of current-carrying capacity of power cables installed in free air
PublikacjaEvaluation of current-carrying capacity of power cables and selection of cross-sectional area of their conductors are mainly performed in accordance with requirements of EN, IEC or IEEE standards. However, these standards do not provide all methods of cables installation and location which occur in practice. Thus, in some cases, performance of advanced modeling of various thermal phenomena, affecting power cables current-carrying...
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Remote sensing in laboratory diagnostics of reinforced concrete elements – current development and vision for the future
PublikacjaContinuous emergence of new concrete types and kinds of reinforcement, as well as technological solutions in the field of structural engineering have made great demand for diagnostic tests of reinforced concrete elements. New challenges and problems facing people require new more efficient tools for laboratory diagnostics than those commonly used. Remote sensing may be the answer to this demand. In this paper the author describes...
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Reactive extrusion of bio-based polymer blends and composites – Current trends and future developments
PublikacjaReactive extrusion is a cost-effective and environmentally-friendly method to produce new materials with enhanced performance properties. At present, reactive extrusion allows in-situ polymerization, modification/functionalization of polymers or chemical bonding of two (or more) immiscible phases, which can be carried out on commonly used extrusion lines. Although reactive extrusion has been known for many years, its application...
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Novel condition monitoring of induction motor bearings via motor current signature analysis
PublikacjaThe paper authors are researching the assessment of bearing conditions in induction motors. The methods developed by the authors are based on measurements and analysis of the motor supply current, which is particularly attractive in the absence of access to the engine. The article provides an overview of selected methods of induction motor bearings diagnostic based on Motor Current Signature Analysis (MCSA). However, there is no...
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Sinusoidal Alternating-Current Voltammetry and Metrological Properties of a Flat Voltammetric Electrode in the Time Domain
PublikacjaIn this paper there were analyzed metrological properties of a flat electrode used to mark ions with the method of sinusoidal alternating-current voltammetry in the situation where on its surface an electrochemical reversible reaction of oxidizing / reduction takes place. The result of the analysis conducted is that such a voltammetric electrode functions like a converter type I. Metrological properties of such an electrode in...
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Carbon dioxide sequestration by industrial wastes through mineral carbonation: Current status and perspectives
PublikacjaMineral carbonation using natural minerals or industrial wastes is a safe and promising strategy for CO2 sequestration. Application of industrial wastes for this purpose has significant ecological and environmental value, which is one of the key green technologies in the global carbon mitigation. This review summarizes the current research status of CO2 mineralization by industrial wastes. This work surveys the mechanisms and capacities...
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Friction Stir Welding of Aluminum in the Aerospace Industry: The Current Progress and State-of-the-Art Review
PublikacjaThe use of the friction stir welding (FSW) process as a relatively new solid-state welding technology in the aerospace industry has pushed forward several developments in different related aspects of this strategic industry. In terms of the FSW process itself, due to the geometric limitations involved in the conventional FSW process, many variants have been required over time to suit the different types of geometries and structures,...
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Polyether-block-amide PEBA membranes for gas separation and pervaporation; current design and applications
PublikacjaPolyether-block-amide (PEBA) membranes have attracted considerable attention for their exceptional efficacy in gas separation and pervaporation processes. This comprehensive review delves into the precise definition, distinguishing characteristics, and diverse applications of PEBA membranes over the past five years. A primary research objective focuses on enhancing gas separation efficiency, primarily through augmenting membrane...
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Current challenges and methodological issues of functional safety and security management in hazardous technical systems
PublikacjaCelem artykułu jest zidentyfikowanie problemów oceny ryzyka w kontekście stosowania systemów elektrycznych / elektronicznych / programowalnych elektronicznych (E/E/PE) z uwzględnieniem aspektów bezpieczeństwa funkcjonalnego i zabezpieczeń (ochrony). Zadaniem rozwiązań bezpieczeństwa funkcjonalnego jest efektywne redukowanie ryzyka wychodząc z poziomu nieakceptowanego. Ryzyko jest definiowane jako kombinacja prawdopodobieństwa wystąpienia...
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The Adaptive Backstepping Control of Permanent Magnet Synchronous Motor Supplied by Current Source Inverter
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Tripping of F-type RCDs for sinusoidal residual current with superimposed smooth DC component
PublikacjaRecent trends in green energy development make that photovoltaics and electric vehicles are applied on an increasing scale. In both photovoltaic and electric vehicle charging installations, a significant value of DC component of the earth fault current may appear, which is a challenge, in particular, for commonly used residual current devices (RCDs). This paper presents results of the laboratory test on the operation of F-type...
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Impact of thermal backfill parameters on current-carrying capacity of power cables installed in the ground
PublikacjaProper design of power installations with the participation of power cables buried in homogeneous and thermally well-conductive ground does not constitute a major problem. The situation changes when the ground is non-homogeneous and thermally low-conductive. In such a situation, a thermal backfill near the cables is commonly used. The optimization of thermal backfill parameters to achieve the highest possible current-carrying capacity...
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Electrical safety in low-voltage DC microgrids with B-type residual current devices
PublikacjaResidual current devices (RCDs) are most popular devices used in low-voltage installations for protection against electric shock and fire. In cases of high risk of electric shock the application of RCDs is mandatory. Currently, the spread of local direct current (DC) microgrids is widely considered. This creates new challenges for protective systems, in particular those based on RCDs. The main purpose of the research is to test...
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Analysis of AC/DC/DC Converter Modules for Direct Current Fast-Charging Applications
PublikacjaThe paper is a comprehensive laboratory comparison study of two galvanic isolated solution off-board battery chargers: (1) Si-based cost-effective case, and (2) SiC-bidirectional ready for vehicle to grid concept case. All circuits are modular, and in both cases the DC/DC converter can be replaced according to the end user requirements (the coupled transformer remains the same and is constructed based on 12xC100 cores to avoid...
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Dc Leakage Current in Isolated Grid-Connected dc Nanogrid - Origins and Elimination Methods
PublikacjaThe LV dc system is a relatively new trend in the distribution sector, which seems to grow widely in the near future due to its promising advantages. In this context, LV dc protection and grounding are challenging issues. Although the galvanically isolated connection mode of dc nanogrid to the ac grid has high reliability, the leakage current can still be injected into the ac grid through the interwinding capacitors and the insulation...
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Study of particle - bubble interaction using atomic force microscopy - current possibilities and challenges
PublikacjaBadania oddziaływań pomiędzy cząstkami mineralnymi i pęcherzykami powietrza są kluczowe do zrozumienia przebiegu flotacji. Wykorzystanie mikroskopii sił atomowych (AFM) i techniki próbnika koloidalnego umożliwia pomiar takich oddziaływań.
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Current technology trends in Electronic Commerce. Przegląd trendów technologii dla e-Commerce.
PublikacjaPrzedstawiono przegląd trendów technologii dla e-Commerce. Skupiono się na rozwiązaniach programowanych w dziedzinie wzorców projektowych oraz zastosowania ebXML.
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Energy quality improvement by ultra rapid L. V. fault current limiting andinterrupting.
PublikacjaPrzedstawiono możliwość ograniczania rozprzestrzeniania się zapadów napięcia w sieciach elektroenergetycznych przy zwarciach przez zastosowanie łączników hybrydowych do ultra szybkiego ograniczania i wyłączania prądów zwarciowych. Referat ma na celu przedstawienie dotychczasowych osiągnięć prac badawczych w dziedzinie łączników ultra szybkich, a także poznanie opinii elektroenergetyki i odbiorców na temat celowości wprowadzenia...
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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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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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Effect of Maximal Apnoea Easy-Going and Struggle Phases on Subarachnoid Width and Pial Artery Pulsation in Elite Breath-Hold Divers
PublikacjaPurpose: The aim of the study was to assess changes in subarachnoid space width (sas-TQ), the marker of intracranial pressure (ICP), pial artery pulsation (cc-TQ) and cardiac contribution to blood pressure (BP), cerebral blood flow velocity (CBFV) and cc-TQ oscillations throughout the maximal breath hold in elite apnoea divers. Non-invasive assessment of sas-TQ and cc-TQ became possible due to recently developed method based on...
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Grinding specifics of plasma coatings melted with high-frequency currents
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Disturbances of Earth magnetic field caused by eddy currents of airplane
PublikacjaThe uniform magnetic field of the Earth in the surrounding of a mobile, metallic object undergoes deformation by eddy currents. The influence of the moving, conducting object on the Earth's total magnetic field depends on the object's shape, position and speed of the changes relative to the magnetic field vector of the Earth, as well as the electric conductivity and the relative magnetic permeability of the material. Disturbances...
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Tripping of F-type RCDs for High-Frequency Residual Currents
PublikacjaResidual current devices (RCDs) are apparatus commonly used for protection against electric shock in low-voltage electrical installations. They protect people in the case of an earth fault or even in the case of direct contact with the live parts. However, to be effective protective devices, RCDs have to detect residual currents of various waveform shapes which appear in modern electrical installations. For this purpose, RCDs...
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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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Modeling the impact of surface currents in a harbor using graph theory
PublikacjaEnsuring security in a harbor requires research into its infrastructure using spatial environmental data. This paper presents a methodology that defines the design of a graph for modeling the interactions between surface currents and moving objects. Combining this graph with port charts that integrate electronic navigation charts with coastal orthophotographs allows us to perform a multidimensional analysis. In addition, the complete...
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Tripping of F-type RCDs for high-frequency residual currents
PublikacjaResidual current devices (RCDs) are apparatus commonly used for protection against electric shock in low-voltage electrical installations. They protect people in the case of an earth fault or even in the case of direct contact with the live parts. However, to be effective protective devices, RCDs have to detect residual currents of various waveform shapes which appear in modern electrical installations. For this purpose, RCDs are...
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REVIEW OF CURRENT RESEARCH ON CHITOSAN AS A RAW MATERIAL IN THREE-DIMENSIONAL PRINTING TECHNOLOGY IN BIOMEDICAL APPLICATIONS
PublikacjaThree-dimensional (3D) biomaterial manufacturing strategies show an extraordinary driving force for the development of innovative solutions in the biomedical sector, including drug delivery systems, disease modelling and tissue and organ engineering. Due to its remarkable and promising biological and structural properties, chitosan has been widely studied for decades in several potential applications in the biomedical field. However,...
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Impact of Low Switching-to-Fundamental Frequency Ratio on Predictive Current Control of PMSM: A simulation study
PublikacjaPredictive current control algorithms for permanent magnet synchronous (PMSM) drives rely on an assumption that within short intervals motor currents can be approximated with linear functions. This approximation may result either from discretizing the motor model or from simplifications applied to the continuous-time model. As the linear current approximation has been recognized as inaccurate in case when the drive operates with...
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Current trends in consumption of multimedia content using online streaming platforms: A user-centric survey
PublikacjaIn its early days, consumption of multimedia content was only possible at a stationary terminal device. The music player was located at home, and had to have a physical drive. Over the last decade, there has been an enormous increase in the number of online streaming platforms. These services enable users to consume rich multimedia content on various devices. Thanks to the widespread and availability of portable devices, any person...
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Verification of safety in low-voltage power systems without nuisance tripping of residual current devices
PublikacjaLow-voltage power systems require initial and periodical verification to check the effectiveness of protection against electric shock. As a protection in case of fault, automatic disconnection of supply is most often used. To verify such a protection measure, the earth fault loop impedance or resistance is measured. This measurement is easy to perform in circuits without residual current devices. When residual current devices are...
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Simulation Studies of Control Systems for Doubly Fed Induction Generator Supplied by the Current Source Converter
PublikacjaThe control system for a Doubly Fed Induction Generator (DFIG) supplied by a grid-connected Current Source Converter (CSC) is presented in this paper. Nonlinear transformation of DFIG model to the multi-scalar form is proposed. The nonlinear control strategy of active and reactive power of DFIG is realized by feedback linearization. In the proposed control scheme, the DFIG model and CSI parameters are included. Two Proportional-Integral...
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Stability Analysis of Shunt Active Power Filter with Predictive Closed-Loop Control of Supply Current
PublikacjaThis paper presents a shunt active power filter connected to the grid via an LCL coupling circuit with implemented closed‐loop control. The proposed control system allows selective harmonic currents compensation up to the 50th harmonic with the utilization of a model‐based predictive current controller. As the system is fully predictive, it provides high effectiveness of the harmonic reduction, which is proved by waveforms achieved...
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Residual Current Devices Operational Characteristics within the Frequency Range 50 Hz to 1000 Hz.
PublikacjaW artykule przedstawiono charakterystyki działania powszechnie stosowanych wyłączników różnicowoprądowych przy prądach różnicowych w zakresie częstotliwości 50÷1000 Hz. Częstotliwość wyższa niż 50 Hz wpływa niekorzystnie na prąd zadziałania wyłączników, a w skrajnych przypadkach mogą one w ogóle nie reagować na wolno narastający prąd różnicowy.
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Current knowledge about self-healing polymers in the aspect of application for full-rubber protective gloves
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On the Use of Automatic Cuts Algorithm for T0 – T – Φ Formulation in Nondestructive Testing by Eddy Current
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The determination and identification of stray current source influences on buried pipelines using time/frequency analysis
PublikacjaZaprezentowano metodę detekcji źródła interferencji prądów błądzących na rurociągach podziemnych w aglomeracjach miejskich z wykorzystaniem łącznej analizy czasowo-częstotliwościowej mierzonych sygnałów. Badania przeprowadzono na rurociągu podziemnym zlokalizowanym w sąsiedztwie dwóch trakcji elektrycznych: tramwajowej i kolejowej. Wyniki analiz zaprezentowano w formie spektrogramów, które ilustrują zmiany spektralnej gęstości...
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Estimation of interior-permanent-magnet-synchronous-motor rotor position by analysis of phase-current derivatives
PublikacjaThis paper describes an algorithm for estimation of IPMSM rotor angular position. The algorithm uses derivatives of motor phase currents resulting from PWM modulation to obtain the rotor position. The presented method is designed for medium- and high-speed range, since it is based on determination of the EMF vector. Calculation of the motor position is performed in every PWM cycle. The standard SV-PWM method is used to determine...
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High step-up continuous input current LCCT-Z-source inverters for fuel cells
PublikacjaFalowniki typu Z (ZSI) przeznaczone są do układów wymagających szerokiej zmiany wzmocnienia napięciowego, np. w energetyce odnawialnej. Ostatnio zaproponowano w literaturze zmienione struktury - falowniki typu Trans-Z (TZSI) oraz typu T (TSI) - w których dzięki zastosowaniu dławików sprzężonych uzyskano lepsze wzmocnienie niż w ZSI. W tym artykule przedstawiono ideę rozszerzonej struktury TZSI. Zaproponowano dwie nowe struktury...
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The effect of PWM frequency on the effectiveness of protection against electric shock using residual current devices
PublikacjaW artykule przedstawiono analizę widmową odkształconego prądu ziemnozwarciowego z obwodu silnika o regulowanej prędkości obrotowej za pomocą przemiennika częstotliwości. Oceniono skuteczność ochrony przeciwporażeniowej wykorzystującej wyłączniki różnicowoprądowe przy różnych wartościach częstotliwości PWM przemiennika. Przedstawiono charakterystykę działania proponowanego wyłącznika różnicowoprądowego.
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A new method of fault loop resistance measurement in low voltage systems with residual current devices
PublikacjaThis paper presents a new method of fault loop resistance measurement in low voltage systems with residual current devices. The method enables measuring fault loop resistance without nuisance tripping of residual current devices, by application an unconventional waveform of measurement current. It is important for proper verification of the effectiveness of protection against electric shock.
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The effect of PWM frequency on the effectiveness of protection against electric shock using residual current devices
PublikacjaW referacie przedstawiono analizę widmową odkształconego prądu ziemnozwarciowego z obwodu silnika o regulowanej prędkości obrotowej za pomocą przemiennika częstotliwości. Oszacowano wpływ tego odkształcenia na próg fibrylacji serca. Analizowano skuteczność ochrony przeciwporażeniowej wykorzystującej wyłączniki różnicowoprądowe przy różnych wartościach częstotliwości PWM przemiennika. Przedstawiono charakterystykę działania zaproponowanego...
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Evaluation of applicability of classic methods of a fault loop impedance measurement to circuits with residual current devices
PublikacjaMeasurement of fault loop impedance in low voltage grids and systems is in most cases performed to verify the effectiveness of protection against electric shock by automatic disconnection of supply. For the sake of measurement accuracy, it is advisable to perform it using large current. Unfortunately, in circuits with residual current devices which are very widely used nowadays, a large measurement current may trigger those devices...
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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...