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Search results for: LEAKAGE CURRENT MEASUREMENT
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Elimination of the negative effect of earth fault current higher frequency on tripping of residual current devices
PublicationCzęstotliwość prądu różnicowego większa niż 50/60 Hz ma niekorzystny wpływ na wyzwalanie wyłączników różnicowoprądowych. Przy zwiększonej częstotliwości prądu różnicowego rzeczywisty prąd zadziałania wyłączników zwiększa się, a niektóre z nich w ogóle nie wyzwalają. W artykule omówiono główne przyczyny zwiększenia się prądu zadziałania wyłączników różnicowoprądowych oraz przedstawiono sposób eliminacji niekorzystnego wpływu zwiększonej...
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Wood Moisture-Content Measurement Accuracy of Impregnated and Nonimpregnated Wood
PublicationThe influence of the impregnation process of pine wood (Pinus sylvestris L.) samples on the electrical resistance changes and the moisture-content measurement accuracy is presented in this paper. In this study, the resistances of impregnated and nonimpregnated green pine timber harvested from northern Poland were compared. An impregnation method based on a vacuum-pressure chamber was used. Copper salts were applied as the impregnated...
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The influence of the motor filtrers on harmonic current emmision in the pro-ective connection of drive systems.
PublicationThis 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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CFD-based evaluation of current-carrying capacity of power cables installed in free air
PublicationEvaluation 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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Evaluation of high-frequency roughness measurement errors for composite and ceramic surfaces after machining
PublicationPrecise characterisation of surface topography is of the greatest importance since many factors directly affect the accuracy of the whole measurement process. In this paper, the variety of surface topographies from machined composite and ceramic workpieces was studied with a special emphasis on the measurement results. Surfaces were subjected to the ground diamond, honing and milling processes. Measurement results were analysed...
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The adaptive backstepping control of PMSM supplied by current source inverter for the field weakening region
PublicationThe sensorless control system of permanent magnet synchronous motor PMSM supplied by current source inverter for field weakening operation is presented in this paper. The adaptive backstepping control system and the backstepping speed observer are presented. The control system is based on multi-scalar variables. The control variables are: dc-link voltage and the output current vector pulsation. The control system was named voltage...
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Spikes removal in surface measurement
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The prototype of a wireless measurement card
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Air Pollutant Emission Measurement
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Modal analysis of railway current collectors using Autodesk Inventor
PublicationThe paper presents the results of modal analysis of railway current collector type 160EC. In the first place, the analysis was carried out analytically for a simplified two lumped mass pantograph model. Then numerical analysis was conducted in the Autodesk Inventor (AI) on the prepared multibody model using the AI modal analysis algorithm, which is based on the finite element method (FEM). Model elements which are most relevant...
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Electrical safety in low-voltage DC microgrids with B-type residual current devices
PublicationResidual 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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Impact of Low Switching-to-Fundamental Frequency Ratio on Predictive Current Control of PMSM: A simulation study
PublicationPredictive 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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Stability Analysis of Shunt Active Power Filter with Predictive Closed-Loop Control of Supply Current
PublicationThis 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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Dynamic unattended measurement based routing algorithm for diffServ architecture
PublicationDynamic routing is very important in terms of assuring QoS in today's packet networks especially for streaming and elastic services. Existing solutions dedicated to dynamic routing are often too complicated and seem to be not usable in real time traffic scenarios where transferred traffic may vary significantly. This was the main reason for research and new routing mechanism proposal which should apply to today's packet networks....
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Oxylipin profiling for clinical research: Current status and future perspectives
PublicationOxylipins are potent lipid mediators with increasing interest in clinical research. They are usually measured in systemic circulation and can provide a wealth of information regarding key biological processes such as inflammation, vascular tone, or blood coagulation. Although procedures still require harmonization to generate comparable oxylipin datasets, performing comprehensive profiling of circulating oxylipins in large studies...
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Using On-line Measurement by Electronic Nose and Computer Simulations for Real-time Control at WWTP
PublicationContinuous investigation of wastewater quality can be carried out by a device called an e-nose. One important feature of the proposed real-time control system for WWTP is that using on-line measurements by e-nose together (Figure 1) with technological sets picked on this basis by means of computer models, it is possible to change treatment process parameters, depending on the current quality of wastewater. It can be used for the...
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Complete Mesogastric Excisions Involving Anatomically Based Concepts and Embryological-Based Surgeries: Current Knowledge and Future Challenges
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Flicker Noise in Resistive Gas Sensors—Measurement Setups and Applications for Enhanced Gas Sensing
PublicationWe discuss the implementation challenges of gas sensing systems based on low-frequency noise measurements on chemoresistive sensors. Resistance fluctuations in various gas sensing materials, in a frequency range typically up to a few kHz, can enhance gas sensing by considering its intensity and the slope of power spectral density. The issues of low-frequency noise measurements in resistive gas sensors, specifically in two-dimensional...
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Experimental validation of the rolling resistance measurement method including updated draft standard
PublicationThe main objective of ROSANNE is the harmonisation and standardisation of the measurement of skid resistance, noise emission and rolling resistance of road pavements. Regarding rolling resistance characterisation, a draft for standardization of a harmonized procedure for classification of road surfaces across Europe has been prepared within WP3 (deliverable 3.5). The procedure deals with the direct measurement on real roads of...
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Cannabinoids: Challenges, opportunities and current techniques towards its extraction and purification for edibles
PublicationDue to the multiple health benefits associated with the consumption of cannabinoids, there is a current trend on continuing to explore their biological properties. Cannabidiol (CBD) is likely to be the most investigated endocannabinoid from the cannabis plant. Unfortunately, the purification of CBD from its natural source and psychotropic analogue (tetrahydrocannabinol, THC) is timely challenging for the research community based...
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Case Study of Stray Current Corrosion of Tall Ship Mast
PublicationNowadays, in the present technical civilization there are numerous complex technical systems that may generate various hazards. Large transport units like ships can be considered as the most dangerous systems. Therefore, it is important to eliminate all possible hazards, especially for ship crewmembers. Destruction of ship structural components caused by vast corrosion is one of these hazards. Usually, its activity leads to a decrease...
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Thermal and Electrodynamic Risk of Residual Current Devices in the Case of Back-Up Protection by Overcurrent Circuit Breakers
PublicationResidual current operated circuit breakers without integral overcurrent protection should be back-up protected. As back-up protection devices, overcurrent circuit breakers are used. The maximum let-through energy and let-through current of the overcurrent devices were evaluated under laboratory conditions. The thermal and electrodynamic risk of residual current devices was analyzed.
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Modification of current-voltage characteristics of planar organic systems by nm-thick interlayer
PublicationEffect of nm-thick interlayer of copper phthalocyanine (CuPc) or perylene dye (MePTCDI) on current-voltage characteristics of planar organic systems is discussed in the work. The MePTCDI layer strongly limits injection of holes from ITO into CuPc, while CuPc limits injection of electrons from ITO into MePTCDI. In the systems with CuPc/MePTCDI heterojunction an explicit photovoltaic effect occurs.
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Novel condition monitoring of induction motor bearings via motor current signature analysis
PublicationThe 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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Conditions for measurement, analog-to-digital conversion and frequency analysis of irregularities of profile surface
PublicationPrzedstawiono uwarunkowania pomiaru, przetwarzania analogowo-cyfrowego i analizy częstotliwościowej nierówności powierzchni toczonych dla celów rozpoznawania ich głównych składowych. Przedstawiono ograniczenia w pomiarze igłą, która odwzorowuje nierówności poprzeczne. Podano zależności parametrów pomiaru cyfrowego nierówności warunkujące zakresy ich rozpatrywania. Dla wartości przedziału próbkowania, dla którego nie jest spełnione...
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Current Status, Barriers and Development Perspectives for Circular Bioeconomy in Polish South Baltic Area
PublicationThe following article presents the current legal situation in Poland as well as in the European Union. Data on biomass production in the Polish South Baltic area were analyzed, along with an indication of the key sectors for the development of bioeconomy. Presentation of the current state of biomass management was made and areas necessary for development were indicated to facilitate the sustainable management of biomass and waste...
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Designing a magnetoacoustic emission measurement configuration for measurement of creep damage in power plant boiler tubes
PublicationOpisywane są własności skonstruowanego detektora emisji magneto-akustycznej (EMA) służącego dla pomiaru stopnia degradacji rurociągów w przemyśle energetycznym. Specjalna budowa biegunów magnesu umożliwia ich dopasowanie do zakrzywionych powierzchni. Układ pomiarowy pozwala na badanie natężenia EMA dla pola wzdłuż osi rury, a także w kierunku obwodowym. Wykazano, iż możliwa jest detekcja zmiany stopnia degradacji materiału na obwodzie...
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Potentiometric Solid-Contact Multisensor System for Simultaneous Measurement of Several Ions
PublicationThe design and performance of potentiometric multisensor system made in solid-contact technology is described. Both, the measuring electrodes as well as the reference electrode are in a compact cell. The system allows for simultaneous measurement of various ions. The characteristics of the electrodes for Na+, K+ and Ca2+ ions were determined using the designed system and compared with ISEs of the same membrane composition in classical...
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The impact of potential leakage from the sub-seabed CO2 storage site on the phosphorus transformation in marine sediments – An experimental study
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Dead-Time Effect Compensation Based on Additional Phase Current Measurements
PublicationThis paper proposes a new method of dead-time effect compensation. The proposed solution is based on additional phase current measurements realized by analog-to-digital converters. These measurements are carried out at the time instants specified by a pulsewidth-modulation (PWM) strategy. This makes it possible to estimate inverter currents at the commutation instants and, finally, to estimate the voltage error caused by dead time. This...
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Current status and future success of renewable energy in Pakistan
PublicationMismatch between energy demand and supply from last two decades has been increasing because of the domination of expensive imported oil in energy mix of Pakistan. To import crude oil Government paid US $ 9 billion in 2008–2009 to meet the energy demands...
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Current status of toxoplasmosis vaccine development
PublicationToksoplazmoza, choroba wywoływana przez wewnątrzkomórkowego pasożyta Toxoplasma gondii jest szeroko rozpowszechniona na całym świecie. Zarażenie tym pasożytem stanowi bardzo poważny problem medyczny i weterynaryjny, ponieważ jest przyczyną ciężkiej wrodzonej postaci choroby (tzw. toksoplazmozy wrodzonej) oraz poronień, które dotyczą zarówno ludzi jak i zwierząt domowych. Toksoplazmoza może mieć także ciężki przebieg u osób upośledzoną...
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Yerba Mate—A Long but Current History
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Current status of liposomal porphyrinoid photosensitizers
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Current research addressing starch acetylation
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Backprojection algorithm for current mode EIT.
PublicationW pracy przedstawiono algorytm rekonstrukcyjny dla TEI wykorzystujący informację o rozpływie prądu pomiędzy elektrody pomiarowe zwarte do potencjału wspólnego. Pokazano, że algorytm jest analogiczny do znanego wcześniej algorytmu określanego jako Backprojection. Przedstawiono przykładowe wyniki rekonstrukcji dla obiektu kołowego.
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Green Chemistry - current and future issues
PublicationW pracy przedstawiono 12 zasad Zielonej Chemii oraz wybrane przykłady stosowania zasad w życiu codziennym, przemyśle, laboratoriach i edukacji. Pokrótce opisano historię Zielonej Chemii oraz przyszłe wyzwania. ZCH dotyczy nowego podejścia do zagadnienia syntezy, przeróbki i wykorzystania związków chemicznych, związanego ze zmniejszeniem zagrożenia dla zdrowia i środowiska. Istnieje wiele publikacji opisujących metodyki analityczne...
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The stationarity characteristics of electrochemical current noise
PublicationPrzedstawiono rezultaty analizy szumu elektrochemicznego generowanego podczas korozji stali 0H18N9 w roztworze 0.1 M H2SO4+0,006 M Cl-. Rejestry uzyskano w warunkach potencjostatycznych. W szumie zaobserwowano trendy i sygnały przejściowe, charakterystyczne dla korozji wżerowej. Trend został usunięty za pomocą aproksymacji wielomianem trzeciego stopnia. Analiza statystyczna wykazała niestacjonarny bądź słabo stacjonarny charakter...
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Bioelectronic tongue: Current status and perspectives
PublicationIn the course of evolution, nature has endowed humans with systems for the recognition of a wide range of tastes with a sensitivity and selectivity which are indispensable for the evaluation of edibility and flavour attributes. Inspiration by a biological sense of taste has become a basis for the design of instruments, operation principles and parameters enabling to mimic the unique properties of their biological precursors. In...
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Review on Current Status of Echinocandins Use
PublicationFungal infections are rising all over the world every year. There are only five medical compound classes for treatment: triazoles, echinocandins, polyenes, flucytosine and allylamine. Currently, echinocandins are the most important compounds, because of their wide activity spectrum and much lower sides effects that may occur during therapy with other drugs. Echinocandins are secondary metabolites of fungi, which can inhibit the...
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Effect of solar radiation on current-carrying capacity of PVC-insulated power cables – the numerical point of view
PublicationPower 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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Quantum Steering Inequality with Tolerance for Measurement-Setting Errors: Experimentally Feasible Signature of Unbounded Violation
Publicationuantum steering is a relatively simple test for proving that the values of quantum-mechanical measurement outcomes come into being only in the act of measurement. By exploiting quantum correlations, Alice can influence — steer — Bob ’ s physical system in a way that is impossible in classical mechanics, as shown by the violation of steering inequalities. Demonstrating this and similar quantum effects for systems of increasing size,...
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Measurement and Analysis of the Radio Wave Polarisation in Off-Body Communications in Indoor Environment
PublicationThe paper describes an analysis of the radio wave polarisation in off-body communications in indoor environment. The measurement stand for polarisation measurements has been shortly described. Five investigated scenarios with different body postures and different antenna placements have been characterize. The vertical and horizontal components of received radio signal have been analysed. The measure used in analysis is a ratio...
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Reduction of measurement data before Digital Terrain Model generation vs. DTM generalisation
PublicationModern data acquisition technologies provide large datasets that are not always necessary in its entirety to properly accomplish the goal of the study. In addition, such datasets are often cumbersome for rational processing, and their processing is time and labour consuming. Therefore, methods that enable to reduce the size of the measurement dataset, such as the generalization of the Digital Terrain Model (DTM) or the reduction...
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Measurement of expenditure efficiency of Polish cities with county rights in the context of quality of life
PublicationThe article is devoted to the measurement of efficiency of overall expenditures. The purpose of the study is to evaluate the efficiency of use of budget resources by local government units in the context of fostering quality of life. The subject of the study is 65 Polish cities with county rights (county status). Calculations were carried out using Data Envelopment Analysis (DEA). The results of analysis confirm the two research...
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Four-state measurement method for direct-reading noise figure measurement of low-gain two-ports.
PublicationOmówiono problemy techniczne pomiaru współczynnika szumu dwuwrotników o małym wzmocnieniu mocy dysponowanej realizowanych przy stosowaniu znanych metod pomiaru współczynnika szumu. Przedstawiono nową czterostanową metodę pomiaru umożliwiającą uniezależnienie wskazań automatycznego miernika współczynnika szumu zarówno od wartośći wzmocnienia dwuwrotnika badanego jak i współczynnika szumu odbiornika pomiarowego. Wyprowadzone zależności...
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Impedance Spectra of RC Model as a Result of Testing Pulse Excitation Measurement Method Dataset
PublicationThe dataset titled Impedance spectra of RC model as a result of testing pulse excitation measurement method contains the impedance spectrum of an exemplary test RC model obtained using pulse excitation. The dataset allows presentation of the accuracy of the impedance spectroscopy measuring instrument, which uses the pulse excitation method to shorten the time of the whole spectrum acquisition.
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Measurement of pulse signal period from incremental encorder by counters of Multifunctuin DAQ devices.
PublicationW artykule omówiono parametry liczników znajdujących się na wielofunkcyjnych kartach akwizycji sygnałów pomiarowych. Przedstawiono przygotowane w środowisku programowania Lab VIEW aplikacje wykorzystujące te liczniki. Służą one do pomiaru i rejestracji długości zadanej liczby okresów mierzonego sygnału oraz liczby okresów uzależnionej od ich długości (metoda zliczania zależnego z wydłużonym czasem pomiaru). Aplikacje te zostały...
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Radioisotope measurement of selected parameters of liquid-gas flow using single detector system
PublicationTo determine the parameters of two-phase flows using radioisotopes, usually two detectors are used. Knowing the distance between them, the velocity of the dispersed phase is calculated based on time delay estimation. Such a measurement system requires the use of two gamma-ray sealed sources. But in some situations it is also possible to determine velocity of dispersed phase using only one scintillation probe and one gamma-ray source....
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Comparison of the measurement techniques employed for evaluation of ambient air odour quality
PublicationThe paper presents the results of investigation on ambient air odour quality in a vicinity of the industrial sewage treatment plant being a part of the crude oil processing plant. The investigation was performed during spring-winter season using a prototype of electronic nose and the Nasal Ranger field olfactometers. The prototype was equipped with a set of six semiconductor sensors by FIGARO Co. and one PID-type sensor. The field...