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Wyniki wyszukiwania dla: electric energy
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Partial Admission Stages of High Efficiency for a Microturbine
PublikacjaThe paper presents the results of a design analysis of a microturbine for a cogeneration micro-power plant working in accordance with organic Rankine cycle. The heat power of the plant is assumed equal to 20kW and the corresponding available electric output is estimated to be about 3 kW. After the design analysis, the axial turbine with partial admission in all stages was built and tested experimentally. Special attentionwas paid...
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Implementation of power transformer controlled switching algorithm
PublikacjaThe article presents two new algorithms of controlled switching the power transformer. The main aim of the paper is to obtain formulas that determine the moments of closing of the circuit breaker poles. The study contains projects of control systems for both algorithms. Mathematical formulas for the time instants of the breaker poles closing were developed on the basis of electric circuit theory and magnetic circuit theory. The...
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Partial Admission Stages of High Efficiency for a Microturbine
PublikacjaThe paper presents the results of a design analysis of a micro-turbine for a co-generation micro-power plant working in accordance with organic Rankine cycle. The heat power of the plant is assumed equal to 20kW and the corresponding available electric output is estimated to be about 3kW. After the design analysis, the axial turbine with partial admission in all stages was built and tested experimentally. Special attention was...
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The Impact of Thermal Stresses on Volume Resistivity: Performance Comparison between TR-XLPE and XLPE Cables
PublikacjaMost failures in electric power cables are attributed to the development of water trees inside the insulating materials. Thus, the development and utilization of Tree Retardant Cross-Linked Polyethylene (TR-XLPE) based cables have recently been given great attention to overcome the treeing issues. TR-XLPE cables use low-density polyethylene compounds suppressing the formation of water trees while retaining excellent electrical,...
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Electrodeposited Biocoatings, Their Properties and Fabrication Technologies: A Review
PublikacjaCoatings deposited under an electric field are applied for the surface modification of biomaterials. This review is aimed to characterize the state-of-art in this area with an emphasis on the advantages and disadvantages of used methods, process determinants, and properties of coatings. Over 170 articles, published mainly during the last ten years, were chosen, and reviewed as the most representative. The most recent developments...
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Modeling of a Quasi-Resonant DC Link Inverter Dedicated to Common-Mode Voltage and Ground Current Reduction
PublikacjaIn 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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Room temperature depinning of the charge-density waves in quasi-two-dimensional 1T-TaS2 devices
PublikacjaWe report on the depinning of nearly commensurate charge-density waves in 1T-TaS2 thin films at room temperature. A combination of the differential current–voltage measurements with the low-frequency noise spectroscopy provides unambiguous means for detecting the depinning threshold field in quasi-2D materials. The depinning process in 1T-TaS2 is not accompanied by an observable abrupt increase in electric current—in striking contrast...
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The Review of the Selected Challenges for an Incorporation of Daylight Assessment Methods into Urban Planning in Poland
PublikacjaThe main objectives of this research it to find out if modern daylight assessment and design methods can be useful for urban residential planning in Poland. The study gives a chance to describe and appraise modern daylight design techniques. The other purpose is to illustrate how daylight knowledge could be used as an incentive to rethink the way urban environments are created. Although daylight design is acknowledged in literature...
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An inverse algorithm for contact heat conduction problems with an interfacial heat source based on a first-order thermocouple model
PublikacjaInverse problems of contact heat conduction with an interfacial heat source are common in various fields of science, engineering and technology. In this study, an algorithm for their solution is developed based on an inverse parametric optimisation method with an impulse response function describing the heat partition and contact heat transfer. A first-order thermocouple model with a time constant parameter is embedded in the impulse...
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Comparison of heat transfer from single- and double-sided heated horizontal plate under free convection in air with constant heat flux condition
PublikacjaThis paper presents the results of an experimental and numerical study of convective heat transfer from a newly designed double-sided heated horizontal plate in air. To ensure equal heat transfer from both surfaces, the plate was equipped with two independently supplied electric heaters and resistance thermometers on each side. Minimizing the plate's thickness reduced lateral heat loss and improved measurement accuracy. The study...
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An Extremely Compact Frequency Reconfigurable Antenna Diplexer Employing Dielectric Liquids
PublikacjaThe letter presents an extremely compact frequency reconfigurable antenna diplexer based on fluidic channels for sub6 GHz applications. The proposed antenna diplexer is modelled by employing half-mode (HM) and quarter-mode (QM) substrateintegrated rectangular cavities, two slots, orthogonal feed lines, and fluidic vias. To comprehend the radiation mechanism, the equivalent circuit, electric field distributions, and frequency responses...
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Public Lighting in a Context of Regeneration Processes in Polish Cities
PublikacjaThe purpose of this paper is to reflect on the role of electric lighting design in urban regeneration processes. The landscape of the modern city is the result of an accumulation of the various physical, economic, social and cultural layers over the centuries. Urban lighting may be described as one of the physical layers which due recent developments in the technology of efficient light sources overcomes a major evolution. With...
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Model-Free Controller Tuning Based on DFT Processing: Application to Induction Motor Drives
PublikacjaIn this paper, we present a new approach based on discrete Fourier transform (DFT) analysis for controller tuning of the closed-loop system with unknown plant. The DFT analysis is used to process the closed-loop measurements collected online to derive the frequency response of an initial closed-loop system that does not provide a good performance. Based on the closed-loop frequency response data, we propose two methods for tuning PID...
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Temperature influence on tire/road noise evaluated by the drum method
PublikacjaAmbient air and road surface temperatures substantially affect the road vehicle noise emission. The temperature influence on tire/road noise depends mainly on tire-road combination. It is different for dense and porous pavements, for bituminous and cement ones. It differs also depending on tires. The correction procedures for temperature effect are still under consideration and preparation. Laboratory experiment was prepared to...
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Current Source Inverter Fed Drive
PublikacjaThis book covers three-phase and multiphase (more than three-phase) motor drives including their control and practical problems faced in the field (e.g., adding LC filters in the output of a feeding converter), are considered. The new edition contains links to Matlab®/Simulink models and PowerPoint slides ideal for teaching and understanding the material contained within the book. Readers will also benefit from the inclusion of: A...
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Planar Microwave Bragg Reflector Resonant Dielectric Sensor
PublikacjaIn this paper, a periodic structure is used to design a microwave Bragg reflector with the help of hexagonal lattice, which provides a 5 GHz wide stopband between the low-pass band with cut-off frequency 2.6 GHz and the bandpass response with start and stop frequency 7.8 GHz and 10.5 GHz, respectively. A defect in lattice allows passing a narrowband signal at 6 GHz which is found, from the dispersion relation, to be in the region...
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Infrared techniques for natural convection investigations in channels between two vertical, parallel, isothermal and symmetrically heated plates
PublikacjaThe effect of the gap width between two symmetrically heated vertical, parallel, isothermal plates on intensity of natural convective heat transfer in a gas (Pr = 0.71) was experimentally studied using the balance and gradient methods. In the former method heat fluxes were determined based on measurements of the voltage and electric current supplying the heaters placed inside the walls. In the latter, heat fluxes were calculated...
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Nonlinear electrical properties of glass-ceramics nanocomposites containing ferroelectric nanocrystallites of Bi2VO5.5
PublikacjaNonlinear A.C. impedance measurements were conducted in the 50BiV-50SrBAlO nanocomposite as a function of frequency, temperature and A.C. voltage. This material is ferroelectric below temperature of 730 K, and above 730 K is a good ion-conductor. For this nanocomposite a low A.C. voltage of 1 V rms is enough to observe high nonlinearities. The origin of these nonlinear effects depends on the temperature and frequency. In the high...
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3-D Printable Metal-Dielectric Metasurface for Risley Prism-Based Beam-Steering Antennas
PublikacjaA 3-D printable, planar, metal-dielectric metasurface-based, 2-D beam-steering system for aperture-type antennas is presented in this paper. This beam steering system, also known as the near-field meta-steering system, comprises two fully passive phase-gradient metasurfaces placed in the antenna’s nearfield region to steer the radiation beam. To address the non-uniform electric field phase of the aperture antenna, phase correction...
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Increasing the Utilization of dc-link Voltage of a Five-Leg VSI Based on Rotor Angle Control of Dual Induction Motors
PublikacjaThis paper introduces an increased utilization of the dc-link voltage of a five-leg voltage source inverter (VSI) based on the rotor flux angle control technique for dual induction motors, IM. The main purpose is to utilize additional abilities provided by a multi-motor drive system in limited operating conditions. Generally, a multi-motor drive system is widely used in electric vehicles (EVs), traction systems and in several industrial...
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An Efficient PEEC-Based Method for Full-Wave Analysis of Microstrip Structures
PublikacjaThis article introduces an efficient method for the equivalent circuit characterization and full-wave analysis of microstrip structures, leveraging the full-wave partial element equivalent circuit (PEEC). In particular, the multilayered Green's function is evaluated using the discrete complex-image method (DCIM) and employed to establish the mixed potential integral equations. The proposed strategy considers time delays for the...
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Ferromagnetic nanocrystallites in the SiO2 - PbO - Fe2O3 glass system
PublikacjaThe structure of 50% SiO2 - 35% PbO - 15% Fe2O3, 50% SiO2 - 30% PbO - 20% Fe2O3 and 50% SiO2 - 25% PbO - 25% Fe2O3 (in mol%) glass was investigated by the means of AFM microscopy and X-ray diffraction. Observation by the atomic force microscopy shows that each of prepared iron oxide glass doesn't have homogeneous structure and some nanocrystallites were detected. Next, test with neodymium magnet found out strong magnetic properties...
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Process zone in the Single Cantilever Beam under transverse loading. - Part II: Experimental
PublikacjaThis paper describes an experimental arrangement to evaluate stress/strain fields in the process zone of asymmetric adhesively bonded joints. A transparent polycarbonate flexible beam was bonded to an aluminium alloy rigid block with an epoxy adhesive in a Single Cantilever Beam (SCB) configuration. The flexible adherend was loaded in the direction parallel to the initial crack front at constant rate. To monitor strains induced...
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Magnetic switching of Kerker scattering in spherical microresonators
PublikacjaMagneto-optical materials have become a key tool in functional nanophotonics, mainly due to their ability to offer active tuning between two different operational states in subwavelength structures. In the long-wavelength limit, such states may be considered as the directional forward- and back-scattering operations, due to the interplay between magnetic and electric dipolar modes, which act as equivalent Huygens sources. In this...
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Sustainable Use of the Catenary by Trolleybuses with Auxiliary Power Sources on the Example of Gdynia
PublikacjaThe current developments in onboard power source technology, in particular, traction batteries, open up new potential in trolleybus transport and also make it possible to introduce electric buses. Thus far, trolleybus transport has required the presence of overhead lines (OHL). Introducing trolleybuses with onboard batteries makes it possible to grow the zero-emissions transport network in places with limited power supply capabilities...
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Novel method of estimation of inertial and dissipative parameters of a railway pantograph model
PublikacjaAn increase in electric railway vehicles service velocity requires that correct interaction between the pantograph and the catenary is ensured. This implies the need for developing mathematical models of pantographs and catenaries and determining their parameters. The article presents a method to determine parameters of mechanical joints of a railway pantograph based on analysis of pantograph subassemblies in swinging motion. The...
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Electric Drives [2020/21]
Kursy OnlineEnergy Technologies, 1 st., 4 sem., stac.
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Visual method for detecting critical damage in railway contact strips
PublikacjaEnsuring an uninterrupted supply of power in the electric traction is vital for the safety of this important transport system. For this purpose, monitoring and diagnostics of the technical condition of the vehicle's power supply elements are becoming increasingly common. This paper presents a new visual method for detecting contact strip damage, based on measurement and analysis of the movement of the overhead contact line (OCL)...
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Investigation of the electrochemical behaviour of AA1050 aluminium alloy in aqueous alkaline solutions using Dynamic Electrochemical Impedance Spectroscopy
PublikacjaThe paper presents the electrochemical behaviour of aluminium alloy AA1050 in aqueous alkaline media in the pH range 14–8.5. Electrochemical study was applied in order to obtain comprehensive information on the mechanism and kinetics of the process of anodic dissolution of aluminium, supplemented by monitoring of surface topography using an electron microscope. The corrosion rate of AA1050 increases with increasing concentration...
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Surface Charge Density Spectra: Complex Analysis of the Electrical Double Layer Developed from Measurements of Hexanol Adsorption Kinetics
PublikacjaA procedure for deriving surface charge density spectra from differential capacitance data is presented in this study, providing a deeper analysis of the generated charge. A set of simulated differential capacitance spectra was determined for three types of adsorption process control: diffusion control, adsorption control, and mixed control. Based on the differential capacitance curves and spectra, surface charge density spectra...
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A Simplified SVPWM Technique for Five-leg Inverter with Dual Three-phase Output
PublikacjaThis article proposes a simplified space vector pulse-width modulation (SVPWM) technique five-leg inverter with dual three-phase output. An idea to fed the dual tree-phase machine by the multiphase voltage source inverters (VSIs) is not new. Dual- and multi-motor drive systems are widely used in the industry applications. The most popular fields are: electric vehicles (EVs) and traction systems. Moreover, the specific characteristic...
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Przestrzenne aspekty produkcji i sprzedaży trolejbusów Solaris Trollino
PublikacjaKomunikacja trolejbusowa nie jest popularną formą transportu miejskiego w Polsce, ale polski producent taboru dla komunikacji - Solaris Bus & Coach - jest wiodącym producentem trolejbusów niskopodłogowych w Europie. W artykule przedstawiono ideę budowy trolejbusów, rozwój konstrukcji oraz postęp w produkcji i sprzedaży trolejbusów w latach 2001-2014. W analizowanym okresie polska firma wprowadziła na rynek nowy produkt – trolejbus...
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Shaking table experimental study on damage mechanism of the disconnecting switch under seismic excitation
PublikacjaThe efficiency of the energetic network is a very import safety issue in the region experienced by the earthquake. High voltage disconnecting switches are important elements of the energetic infrastructure used to separate electric circuits (i.e. during repairs), which should not be damaged remaining fully operational. The aim of the paper is to show the results of the shaking table experimental investigation focused on damage...
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Wavelet transform-based approach to defect identification in railway carbon contact strips.
PublikacjaPantographs of electric rail vehicles are fitted with carbon contact strips, which slide along the contact wire of catenary to provide constant electrical contact. Contact strips are exposed to wear and damages. Using damaged contact strips significantly increases the risk of catenary rupture. Therefore, their technical condition has to be inspected frequently. In previous work a 3D laser scanning system was proposed for recording...
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Electrochemical synthesis of 2D copper coordination-polymers: Layer-stacking deviation induced by the solvent and its effect on the adsorptive properties
PublikacjaA 2D Cu-based Metal-Organic Framework (MOF), namely copper-terephthalate (Cu(1,4-BDC)), was successfully synthesized by electrochemical method for effective methylene blue (MB) sorption from aqueous solutions. The composition, morphology, and the presence of functional groups in the obtained material were verified by Fourier Transform Infrared spectroscopy (FTIR), Powder X-Ray Diffraction (PXRD), Thermal (TGA), and Elemental (EA)...
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Sano-Tachiya-Noolandi-Hong, Onsager and Braun models vs Monte Carlo simulation of charge photogeneration in organic solids
PublikacjaThe Sano-Tachiya-Noolandi-Hong (STNH), Onsager, and Braun models as well as Monte Carlo (MC) simulations of charge recombination/separation have been applied for the first time to reproduce the results of the electromodulated photoluminescence measurements in vacuum-evaporated films of fluorescent materials commonly used in optoelectronic devices. The values of the electron-hole pair final recombination speed in the monomer emitters:...
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Aptamer based tools for environmental and therapeutic monitoring: A review of developments, applications, future perspectives
PublikacjaNucleic acids in the form of aptamers play a growing and significant role in the targeted and rapid analysis of environmental sample composition and medical analyses. In this paper, the review of both aptamers synthesis methods as well as application of these short chain oligonucleotides (with critical comments on their strong and weak features) are given. The first ones include: systematic evolution of ligands by exponential enrichment...
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Ce site dilution effects in the antiferromagnetic heavy fermion CeIn3
PublikacjaLa-doped intermetallic single crystals of Ce1−xLaxIn3 were synthesized via an In self-flux method throughout the entire range (x = 0–1). The prototypical heavy-fermion compound CeIn3 shows an antiferromagnetic phase transition at 10.1 K and becomes superconducting near a critical pressure where TN is completely suppressed. As the La concentration increases, Ce moments are diluted, and the lattice constant increases linearly, satisfying Vegard’s...
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Core–shell excitation of isoxazole at the C, N, and O K-edges – an experimental NEXAFS and theoretical TD-DFT study
PublikacjaThe near-edge X-ray absorption fine structure (NEXAFS) spectra of the gas-phase isoxazole molecule have been measured by collecting total ion yields at the C, N, and O K-edges. The spectral structures have been interpreted using time-dependent density functional theory (TD-DFT) with the short-range corrected SRC2-BLYP exchange–correlation functional. Experimental and calculated energies of core excitations are generally in good...
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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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Technological innovation and cost-benefit analysis of safety-related solutions
PublikacjaW rozdziale przedstawia się aktualne zagadnienia dotyczące innowacji technologicznych oraz analizę kosztów i efektów rozwiązań związanych z bezpieczeństwem na przykładzie systemów elektrycznych, elektronicznych i programowalnych elektronicznych (E/E/PE), pełniących funkcje monitorowania, sterowania i zabezpieczeń w instalacjach podwyższonego ryzyka. Podkreśla się znaczenie kryteriów związanych z bezpieczeństwem, takich jak tolerowalność...
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Functional safety in the context of risk appraisal criteria and cost-benefit analysis
PublikacjaRozdział przedstawia aktualne zagadnienia dotyczące analizy kosztów i efektów rozwiązań związanych z bezpieczeństwem na przykładzie systemów elektrycznych, elektronicznych i programowalnych elektronicznych (E/E/PE) pełniących funkcje sterowania i zabezpieczeń w obiektach podwyższonego ryzyka. Podkreśla się znaczenie kryteriów związanych z bezpieczeństwem, takich jak tolerowalność ryzyka (TOR) w kontekście analizy kosztów i efektów...
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Synthesis and modification of reduced graphene oxide aerogels for biofuel cell applications
PublikacjaWe have carried out the preparation of reduced graphene oxide aerogels using eco-friendly method that is based on the Hummers method of graphite oxidation without the use of NaNO3 that produces toxic gases. To obtain a porous 3D structure of reduced graphene oxide, we performed the hydrothermal reduction at elevated temperature. We also prepared the rGO aerogel/CNT composite using multiwalled carbon nanotubes as linkers. The rGO...
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Electronic States of Tris(bipyridine) Ruthenium(II) Complexes in Neat Solid Films Investigated by Electroabsorption Spectroscopy
PublikacjaWe present the electric field-induced absorption (electroabsorption, EA) spectra of the solid neat films of tris(bipyridine) Ru(II) complexes, which were recently functionalized in our group as photosensitizers in dye-sensitized solar cells, and we compare them with the results obtained for an archetypal [Ru(bpy)3]2+ ion (RBY). We argue that it is difficult to establish a unique set of molecular parameter values by discrete parametrization...
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Design and investigations of a micro-turbine flow part
Publikacja-generative micro-power plant with the HFE7100 as a working medium was designed and built for experimental investigations. The heat output of the plant was assumed equal to 20 kW, while the electric output amounted to about 3kW.In the paper a multi-stage micro-turbine with partial admission of all the stages is described in detail and the results of the particular experimental investigations and numerical calculations are shown,...
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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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New synthesis route of highly porous InxCo4Sb12 with strongly reduced thermal conductivity
PublikacjaHighly porous, In-filled CoSb3 skutterudite materials with an attractive thermoelectric figure of merit (ZT * 1) and corresponding dense samples were fabricated through the cost-effective method of reduction in oxides in dry hydrogen and the pulsed electric current sintering (PECS) method, respectively. The reduction process was described in detail using in situ thermogravimetric analysis of Co2O3, Sb2O3 and In(NO3)35H2O separately...
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Relatively high-Seebeck thermoelectric cells containing ionic liquids supplemented by cobalt redox couple
PublikacjaMeanwhile no general and reliable equation determining the Seebeck coefficient (S e ) and involving electro-chemical reaction effects was derived for solutions. We reported the database of 15,000 ionic liquids supplemented by three different redox couple systems: 0.01 mol/l Co 3+/2+ (bpy) 3 , 0.01 mol/l I 3-/3I- and 0.2 mol/l 3- /3I- , and the corresponding estimated Seebeck coefficients. We also reported methods for estimating...
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Synthesis of CoFe2O4 Nanoparticles: The Effect of Ionic Strength, Concentration, and Precursor Type on Morphology and Magnetic Properties
PublikacjaThe present study highlights the effect of metal precursor types (SO4 2¯, Cl¯, and NO3¯), their concentration, and the influence of ionic strength of reaction environment on the morphology, surface, and magnetic properties of CoFe2O4 particles. The magnetic nanoparticles were obtained by chemical coprecipitation in alkaline medium at increasing metal concentration in the range of 0.0425 mol·dm-3 to 0.17 mol·dm-3 and calcination...
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Dual Active Bridge (DAB) DC-DC converter for multilevel propulsion converters for electrical multiple units (EMU)
PublikacjaSemiconductor power devices made from silicon carbide (SiC) reached a level of technology enabling their widespread use in power converters. Two different approaches to implementation of modern traction converters in electric multiple units (EMU) have been presented in recent years: (i) 3.3-kV SiC MOSFET-based three-level PWM inverter with regenerative braking and (ii) 6.5-kV IGBT-based four-quadrant power electronic traction transformer...