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Search results for: VOLTAGE DOUBLER
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Low-Voltage LDO Regulator Based on Native MOS Transistor with Improved PSR and Fast Response
PublicationIn this paper, a low-voltage low-dropout analog regulator (ALDO) based on a native n-channel MOS transistor is proposed. Application of the native transistor with the threshold voltage close to zero allows elimination of the charge pump in low-voltage regulators using the pass element in a common drain configuration. Such a native pass transistor configuration allows simplification of regulator design and improved performance,...
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Four Level Diode-Clamped Back-To-Back Converter with Active DC Link Voltage Control
PublicationThis article presents the design and control of 4L-DC back-to-back converter. To solve the DC link voltage balancing problem in four-level converter a new three-level double chopper topology based on PO-PWM modulation was designed and successfully tested. Also, the paper describes two phase space vector pulse width modulation 2P-SVPWM based on the shape function of finite elements. The control structure with modified Dead-Beat...
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Single-phase, Five-level Inverter with SPWM-Based Neutral Point Voltage Balancing Scheme
PublicationMultilevel inverter topologies provide several advantages over two-level inverter configuration. These benefits are the reason for the growing interest in multilevel topologies among research society. One of the most popular topological concepts (diode and active switch clamping) requires neutral-point potential balancing due to series-connected capacitor banks across the input dc link in such derived inverter configurations. This...
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Low-Voltage Low-Power Filters with Independent ω0 and Q Tuning for Electronic Cochlea Applications
PublicationAn acoustic second-order low-pass filter is proposed for filter banks emulating the operation of a human cochlea. By using a special filter structure and an innovative quality (Q)-factor tuning technique, an independent change of the cutoff frequency (ω0) and the Q-factor with unchanged gain at low frequencies is achieved in this filter. The techniques applied result in a simple filter design with low Q-factor sensitivity to component...
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An algorithm for listing all minimal double dominating sets of a tree
PublicationWe provide an algorithm for listing all minimal double dominating sets of a tree of order $n$ in time $\mathcal{O}(1.3248^n)$. This implies that every tree has at most $1.3248^n$ minimal double dominating sets. We also show that this bound is tight.
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Experimental and numerical studies of double corrugated steel arch panels
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Infiltration in a double-porosity medium: Experiments and comparison with a theoretical model
PublicationThis paper presents experimental verification of the mathematical model of unsaturated flow in double‐porosity soils developed by the asymptotic homogenization method. A series of one‐dimensional infiltration experiments was carried out in a column filled with a double‐porosity medium composed of a mixture of sand and sintered clayey spheres arranged in a periodic manner. The unsaturated hydraulic properties of each porous material...
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Fake VIP Attacks and Their Mitigation via Double-Blind Reputation
PublicationIn a generic setting subsuming communication networks, resource sharing systems, and multi-agent communities, a client generates objects of various classes carrying class-dependent signatures, to which a server assigns class-dependent service quality. A Fake VIP attack consists in false declaration of a high class, with an awareness that detection of object signature at the server side is costly and so invoked reluctantly. We show...
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Model of the double-rotor induction motor in terms of electromagnetic differential
PublicationThe paper presents a concept, a construction, a circuit model and experimental results of the double-rotor induction motor. This type of a motor is to be implemented in the concept of the electromagnetic differential. At the same time it should fulfill the function of differential mechanism and the vehicle drive. One of the motor shafts is coupled to the direction changing mechanical transmission. The windings of the external rotor...
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An upper bound for the double outer-independent domination number of a tree
PublicationA vertex of a graph is said to dominate itself and all of its neighbors. A double outer-independent dominating set of a graph G is a set D of vertices of G such that every vertex of G is dominated by at least two vertices of D, and the set V(G)\D is independent. The double outer-independent domination number of a graph G, denoted by γ_d^{oi}(G), is the minimum cardinality of a double outer-independent dominating set of G. We prove...
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Double-Wound O-Ring Retraction for Chylothorax Surgery in Dogs
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Broadside Coupled Stripline with Double-Side UC-PBG Structure.
PublicationPoddano analizie symetryczną linię paskową z dwustronnie umieszczoną na płaszczyznach masy strukturą typu UC-PBG (uniplanar compact-photonic bandgap).Zaprojektowano, wykonano i pomierzono sprzęgacz wykonany w oparciu o tego typu prowadnicę. Miniaturyzacja wymiarów układu potwierdziła spodziewany efekt spowolnienia fali wywołany wprowadzeniem struktury UC-PBG.
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Broadside coupled stripline with double-side UC-PBG structure
PublicationRozważono strukturę linii paskowych sprzężonych szerokim bokiem z periodycznie zaburzoną metalizacją masy typu UC-PBG (Uniplanar Compact - Photonic BandGap). W celu oceny przydatności struktury zaprojektowano, wykonano i przebadano sprzęgacz 3dB. Potwierdzono przewidywany efekt spowolnienia fali (slow wave effect), którego konsekwencją jest możliwość znacznej redukcji wymiarów układu.
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pH/Organic Solvent Double-Gradient Reversed-Phase HPLC
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The Unfolded Protein Response: A Double-Edged Sword for Brain Health
PublicationEfficient brain function requires as much as 20% of the total oxygen intake to support normal neuronal cell function. This level of oxygen usage, however, leads to the generation of free radicals, and thus can lead to oxidative stress and potentially to age-related cognitive decay and even neurodegenerative diseases. The regulation of this system requires a complex monitoring network to maintain proper oxygen homeostasis. Furthermore,...
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Synthesis and properties of the double perovskites La2NiVO6, La2CoVO6 i La2CoTiO6
PublicationW publikacji przedstawiono sposób syntezy, analizę dyfrakcji rentgenowskiej (xrd) i badania podatności magnetycznej tzw. podwójnych związków perowskitowych La2NiVO6, La2CoVO6 i La2CoTiO6. Badane związki są półprzewodnikami ze stosunkowo wąską szerokością przerwy energetycznej dla La2NiVO6, La2CoVO6 i nieznacznie powyżej 1 eV powyżej La2CoTiO6.
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A lower bound on the double outer-independent domination number of a tree
PublicationA vertex of a graph is said to dominate itself and all of its neighbors. A double outer-independent dominating set of a graph G is a set D of vertices of G such that every vertex of G is dominated by at least two vertices of D, and the set V(G)D is independent. The double outer-independent domination number of a graph G, denoted by gamma_d^{oi}(G), is the minimum cardinality of a double outer-independent dominating set of G. We...
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A low complexity double-talk detector based on the signal envelope
PublicationA new algorithm for double-talk detection, intended for use in the acoustic echo canceller for voice communication applications, is proposed. The communication system developed by the authors required the use of a double-talk detection algorithm with low complexity and good accuracy. The authors propose an approach to doubletalk detection based on the signal envelopes. For each of three signals: the far-end speech, the microphone...
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Preparation of double-sided self-adhesive tape Si-PSA
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Uptake and Release of Double‐Walled Carbon Nanotubes by Mammalian Cells
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Facilitating the CVD synthesis of seamless double-walled carbon nanotubes
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Buckling analysis of a non-concentric double-walled carbon nanotube
PublicationOn the basis of a theoretical study, this research incorporates an eccentricity into a system of compressed double-walled carbon nanotubes (DWCNTs). In order to formulate the stability equations, a kinematic displacement with reference to the classical beam hypothesis is utilized. Furthermore, the influence of nanoscale size is taken into account with regard to the nonlocal approach of strain gradient and the van der Waals interaction...
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Doppler effect in the CW FM sonar
PublicationWhen sonars are used for military purposes they have to ensure unobtrusive operation, a feature that can be potentially secured by 'silent sonar' or continuous wave frequency modulation sonars (CW FM sonars). The article presents how these sonars operate and identifies the relations between their parameters. The Doppler effect and its impact on the CW FM sonar are studied to identify how it affects the sonar's parameters. The results...
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Induced Sheath Voltages In 110 Kv Power Cables – Case Study
PublicationThe paper considers shock hazard due to induced sheath voltages in 110 kV power cables. Various configurations of the metallic sheaths bonding and earthing (single-point bonding, both-ends bonding, cross-bonding) are analysed. Taking into account shock hazard and ability of the system to power transfer an optimal configuration is proposed.
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Induced sheath voltages in 110 kV power cables – case study
PublicationThis 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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A New Approach to the PWM Modulation for the Multiphase Matrix Converters Supplying Loads with Open-End Winding.
PublicationThis article presents three variants of the Pulse Width Modulation (PWM) for the Double Square Multiphase type Conventional Matrix Converters (DSM-CMC) supplying loads with the open-end winding. The first variant of PWM offers the ability to obtain zero value of the common-mode voltage at the load's terminals and applies only six switches within the modulation period. The second proposal archives for less Total Harmonic Distortion...
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Evaluative analysis of 2- and 3-level DC/DC converters for high-voltage high-power applications
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Optimized Space Vector Modulation strategy for five phase voltage source inverter with third harmonic injection
PublicationThis paper presents a simple and an effective SVM algorithm for five-phase Voltage-Source Inverters with the possibility to control independently the voltage vectors for fundamental and auxiliary orthogonal subspaces. The essential benefit is that output voltage is generated using only four active voltage vectors with limited numbers of switching. In the proposed solution, four active vectors are arbitrary chosen, independent of...
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Voltage and frequency regulation of a standalone induction generator by reduced-rating power electronic compensators - comparative evaluation
PublicationIn this paper are considered two fundamental topologies of power electronic compensators for voltage and frequency control of a standalone self-excited induction generator (IG) system. These are voltage and current source inverter based shunt compensators with energy storage. The aim of this study is to assess main features of both topologies in dynamic and steady-state IG operation. The whole system is modelled with the aid of...
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Study of the Operation of Synchronous Generator Voltage Regulator During the Creation of Post Blackout Start-up Path
PublicationThis paper presents the influence of automatic voltage regulator (AVR) of synchronous generator on the process of creation of post black-out start-up path. Two elements of AVR have a significant impact on this process: underexcitation limiter (UEL) and load compensation (LC). The authors present a theoretical investigation and simulation results that illustrate how the mentioned elements of AVR affect voltage levels in a power...
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space-vector pulse width modulation for three-level npc converter with the neutral point voltage control
PublicationPrzedstawiono strategię modulacji PWM dla trójpoziomowych falowników NPC z predykcją i kompensacją asymetrii rozkładu napięcia na kondensatorach obwodu pośredniczącego
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Experimental verification of a new method of loop resistance testing in low voltage systems with residual current devices
PublicationA periodical verification of the effectiveness of protection against electric shock shall be performed in low voltage systems. The scope of this verification includes loop impedance/resistance testing. If a residual current device is installed in a tested circuit, this testing is problematic. A residual current device trips out during the test, because of the high value of measurement current. This precludes the execution of the...
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Modeling of a Quasi-Resonant DC Link Inverter Dedicated to Common-Mode Voltage and Ground Current Reduction
PublicationIn this paper, the modeling methodology of the AC drive system with a Parallel Quasi-Resonant DC Link Inverter (PQRDCLI) is described. A presented modeling approach is an attractive tool used for the effective evaluation of a common-mode (CM) voltage and grounds current reduction methods. Designed models of inverter, induction machine (IM), and cable are simple, thus the methods for parameter extraction are not complicated. Verification...
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Integrated algorithm for selecting the location and control of energy storage units to improve the voltage level in distribution grids
PublicationThis paper refers to the issue that mainly appears in distribution grids, where renewable energy sources (RES) are widely installed. In such grids, one of the main problems is the coordination of energy production time with demand time, especially if photovoltaic energy sources are present. To face this problem, battery energy storage units (ESU) can be installed. In recent years, more and more attention has been paid to optimizing...
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Modified SPWM Technique with Zero-Sequence Voltage Injection for a Five-Phase, Three-Level NPC Inverter
PublicationThis article presents a modified sinusoidal pulse-width modulation (SPWM) scheme for a five-phase, three-level neutral-point-clamped inverter. The modulation scheme deploys a modified min–max function to inject the zero-sequence components into the reference modulating signals; hence enabling the effective utilization of the DC-link voltage. Balanced split-input DC-link voltages were achieved through further incorporation of adjustable...
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Statistics of AFM current-voltage curves
Open Research DataMapping surface electrical conductivity offers enormous cognitive possibilities regarding the structure and properties of modern materials. The technique invented for this purpose (Conductive AFM) by Murrel's team and colleagues allows independent monitoring of the local conductivity of materials in correlation with the topographic profile. The mentioned...
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The importance of the bottom layer in double-layer porous asphalt for noise reduction
PublicationDouble-layer porous asphalt concrete (DPAC) surfaces are generally considered to be the acoustically most effective low noise road surfaces ready for implementation. While DPAC used on highways in warm climates may have an average life of around 8 years, in Scandinavia with severe winter climate DPAC usually survive only about 3 years; partly due to wear of studded tyres. An ongoing project in Sweden, applying DPAC and single-layer...
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Bearing estimation using double frequency reassignment for a linear passive array
PublicationThe paper demonstrates the use of frequency reassignment for bearing estimation. For this task, signals derived from a linear equispaced passive array are used. The presented method makes use of Fourier transformation based spatial spectrum estimation. It is further developed through the application of two-dimensional reassignment, which leads to obtaining highly concentrated energy distributions in the joint frequency-angle domain...
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Thermal and technological aspects of double face grinding of Al2O3 ceramic materials
PublicationDouble face grinding with planetary kinematics is a process to manufacture workpieces with plan parallel functional surfaces, such as bearing rings or sealing shims. In order to increase the economic efficiency of this process, it has to be advanced permanently. The temperature in the contact zone of most grinding processes has a huge influence on the process efficiency and the workpiece qualities. In contrast to most grinding...
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Optimization of using recuperative braking energy on a double-track railway line
PublicationIn the introduction, possible ways of reusing energy from recuperation are presented. Next, the paper investigates the possibility of using regenerative braking in the range allowed by the detailed timetable by adopting the method of transferring the recovered electric energy directly to the catenary and immediate use of this energy by another train at the same power section. In the main part of the work, it is shown, that the...
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Double amino acid – A novel molecule enabling peptide interpenetrating structures
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Modeling of unsaturated water flow in double-porosity soils by the homogenization approach.
PublicationGrunty o podwójnej porowatości zbudowane są z dwóch materiałów o znacznie różniących się parametrach hydraulicznych. Ze względu na tą szczególną strukturę, podczas przepływu nieustalonego w tego typu gruntach wytwarzają się lokalne różnice ciśnienia kapilarnego. W artykule przedstawiono model przepływu w gruntach o podwójnej porowatości w skali makroskopowej z uwzględnieniem efektów lokalnych. Model otrzymano metodą homogenizacji....
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Going into the research of dampers configuration for bodies under double load conditions.
PublicationJednym z etapów projektowania układów mechanicznych jest dobranie wartości sztywności i tłumienia elementów i dopasowanie ich do planowanego zachowania mechanizmu. Proces ten można uprościć, gdy uda się połączyć komputerowe modelowanie mechanizmów i optymalizację numeryczną. W pracy zajęto się doborem elementów tłumiących. Zaproponowano optymalne ustawienie oraz optymalne wartości współczynników dla układów stabilizujących położenie...
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Control system based on the modified multiscalar model for the double fed machine
PublicationPrzedstawiono układ sterowania maszyną asynchroniczą dwustronnie zasilaną wykorzystujący zmodyfikowany model multisaklarny. Wprowadzone nielinowe sprzężenia pozwalają na podział systemu na dwa niezależne podukłady. Pododuje to brak zauważalnych sprzężeń przy regulacji mocy czynnej i biernej regulowanej przez kontrolery PI. W układzie wyeliminowano konieczność stosowania kaskadowego połączenia regulatorów. Przedstawiono wyniki symulacji.
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Investigation of the double isolator using three-strip Ferrite Coupled Line
PublicationArtykuł prezentuje badania izolatora skonstruowanego z sekcji trój-paskowej ferrytowej linii sprzężonej. Element został zaprojektowany na dwa sposoby: jako kaskadowe połączenie dwóch cyrkulatorów oraz jako struktura planarna zawierająca rezystory. Izolator zbadano teoretycznie i eksperymentalnie.
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Effect of concentration boundary layers on mechanical pressure in a double-membrane system
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Numerical calculations of behaviour of ship double-bottom structure during grounding
PublicationIdeą projektu CORET jest dodanie do obecnej konstrukcji dna podwójnego statku specjalnych powłok polimerowo-betonowych w celu zwiększenia odporności na rozszczelnienie podczas kolizji, czy wejścia na mieliznę. Aby poprawnie zaprojektować te bariery ochronne konieczne jest przeprowadzenie symulacji numerycznej. Tworzenie modelu numerycznego konstrukcji podczas kolizji jest bardzo złożone i wymaga wykonania symulacji pomocniczych...
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<title>Temperature sensor based on double-core optical fiber</title>
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Numerical analysis of CO2-water separation in a horizontal double T-junction
PublicationCarbon dioxide is considered one of the main factors leading to global warming. Considering the significant impacts of CO2 on climate change, various technologies have been developed in recent decades to control carbon emission, such as for example CO2 capture and storage. The developed cycle of a negative CO2 emission power plant includes some devices, out of which, separator plays an indispensable role. To this end, T-junction...
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Thermal and technological aspects of double face grinding of C45 carbon steel
PublicationIn grinding, the contact zone temperature is a decisive factor influencing the achievable surface quality and the grinding tool wear. In contrast to other grinding processes, only few information regarding double face grinding with planetary kinematics when processing steel is known up to date. Since the successive substitution of in-dustrial double-sided lapping processes by double-sided grinding, it has become necessary to the...