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Database of the minimal sets of Lefschetz periods for Morse-Smale diffeomorphisms of a connected sum of g real projective planes.
Dane BadawczeMorse–Smale diffeomorphisms, structurally stable and having relatively simple dynamics, constitute an important subclass of diffeomorphisms that were carefully studied during past decades. For a given Morse–Smale diffeomorphism one can consider “Minimal set of Lefschetz periods”, which provides the information about the set of periodic points of considered...
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Long term measurements of PM1, PM2.5, PM10 and NO2 in open-air at Gdansk (Poland) area using low-cost sensors together with the reference results
Dane BadawczeThe measurements results of open-air measurements made using the following low-cost sensors: particulate matter (PM) sensor SPS30 from Sensirion, NO2 electrochemical sensor SGX-7NO2 from SGX Sensortech, NO2 electrochemical sensor 7E4-NO2 from SemaTech, compact MOS air quality sensor MiCS 2714 from SGX Sensortech, BME280 (Bosch) environmental sensor...
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Working in harmony with nature. Green office buildings in a present-day city
PublikacjaMetropolis - as main point of people's migration, mostly because of work, have to face sustainable development as a strategy for the near future. This article describes possible ways leading to the best office building concepts in the design process. Searching for a workspace in harmony with nature is one of the aspects of a balanced development. The challenge is to create functional, compact, environmentally friendly and healthy...
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An algorithm for enhancing macromodeling in finite element analysis of waveguide components
PublikacjaAn algorithm for enhancing the finite element method with local model order reduction is presented. The proposed technique can be used in fast frequency domain simulation of waveguide components and resonators. The local reduction process applied to cylindrical subregions is preceded by compression of the number of variables on its boundary. As a result,the finite element large system is converted into a very compact set of linear...
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Minimal Sets of Lefschetz Periods for Morse-Smale Diffeomorphisms of a Connected Sum of g Real Projective Planes
PublikacjaThe dataset titled Database of the minimal sets of Lefschetz periods for Morse-Smale diffeomorphisms of a connected sum of g real projective planes contains all of the values of the topological invariant called the minimal set of Lefschetz periods, computed for Morse-Smale diffeomorphisms of a non-orientable compact surface without boundary of genus g (i.e. a connected sum of g real projective planes), where g varies from 1 to...
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Application of the laser diode with central wavelength 975 nm for the therapy of neurofibroma and hemangiomas
PublikacjaThis paper presents newly developed dermatological laser (with central wavelength 975 nm) for application in therapies requiring deep penetration of tissue, e.g. cutaneous (dermal) neurofibroma (Recklinghausen disease) and hemangiomas. This laser can work either in pulse or continues wave mode. Laser radiation is transmitted toward the application region by optical fiber with a diameter of 0.6 mm. The compact design of the laser...
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Generalized Gradient Equivariant Multivalued Maps, Approximation and Degree
PublikacjaConsider the Euclidean space Rn with the orthogonal action of a compact Lie group G. We prove that a locally Lipschitz G-invariant mapping f from Rn to R can be uniformly approximated by G-invariant smooth mappings g in such a way that the gradient of g is a graph approximation of Clarke’s generalized gradient of f . This result enables a proper development of equivariant gradient degree theory for a class of set-valued gradient...
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Sodium nitrite as a corrosion inhibitor of copper in simulated cooling water
PublikacjaThe corrosion inhibition behavior of sodium nitrite (NaNO2) towards pure copper (99.95%) in simulated cooling water (SCW) was investigated by means of electrochemical impedance spectroscopy (EIS) and dynamic electrochemical impedance spectroscopy (DEIS). NaNO2 interferes with metal dissolution and reduce the corrosion rate through the formation or maintenance of inhibitive film on the metal surface. Surface morphologies illustrated...
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Analysis of electromagnetic disturbances in DC network of grid connected building-integrated photovoltaic system
PublikacjaThis paper focuses on conducted electromagnetic interference (EMI) emissions and propagation in the DC network of grid connected building integrated photovoltaic (PV) system. The investigated PV system, consists of ten solar panels, cabling and the grid-connected one phase inverter. The EMI simulation model of the real PV system has been developed with the aid of impedance analyzer measurements of solar panels and the DC network...
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A 3-dB coupler with UC-PBG structure
PublikacjaPrzedstawiono nową konstrukcję sprzęgacza z liniami paskowymi sprzężonymi szerokim bokiem oraz zmodyfikowaną warstwą metalizacji masy. Modyfikacja metalizacji polega na periodycznym wytrawieniu dwuwymiarowej struktury szczelin, nazywanej strukturą uniplanarnej zwartej przerwy fotonicznej (UC-PBG: Uniplanar Compact Photonic BandGap). Potwierdzono przewidywane wcześniej zjawisko spowolnienia fali oraz powiększenia wielkości sprzężenia...
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Harmonic Analysis
Dane BadawczeWe construct a decomposition of the identity operator on a Riemannian manifold M as a sum of smooth orthogonal projections subordinate to an open cover of M. This extends a decomposition on the real line by smooth orthogonal projection due to Coifman and Meyer (C. R. Acad. Sci. Paris, Sér. I Math., 312(3), 259–261 1991) and Auscher, Weiss, Wickerhauser...
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Wpływ uwarunkowań rzeczywistych na pracę równoległego filtru aktywnego sterowanego ze sprzężeniem od prądu zasilającego
PublikacjaW artykule przedstawiono wpływ uwarunkowań rzeczywistych na pracę równoległego filtru aktywnego i zdolność kompensacji prądów harmonicznych. Zbadano wpływ opóźnień czasowych wynikających z implementacji cyfrowej sterowania, wpływ impedancji zwarciowej sieci zasilającej oraz błędów generowania napięcia przekształtnika na jakość kompensacji filtru. Badania symulacyjne przeprowadzono dla trzech układów sterowania: otwartego, zamkniętego...
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AFM-assisted investigation of conformal coatings in electronics
PublikacjaPurpose – This paper aims to presents a new method of investigation of local properties of conformal coatings utilized in microelectronics. Design/methodology/approach – It is based on atomic force microscopy (AFM) technique supplemented with the ability of local electrical measurements, which apart from topography acquisition allows recording of local impedance spectra, impedance imaging and dc current mapping. Potentialities...
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Determination of time dependence of coated metal electrical and electrochemical parameters during exposure using principal component analysis
PublikacjaThe use of the principal component analysis (PCA) permits the complex and quantitative analysis of the time dependence of electrical and electrochemical parameters of coated metal obtained by fitting impedance data. So far, changes in electrical and electrochemical parameters during exposure were analyzed independently. In this way, some of the information contained in the relationship between changes in parameters over time are...
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Dielectric properties of barium-vanadate glasses
Dane BadawczeThe linear impedance of barium-vanadate glasses was measured. Samples of the composition of xBaO-(100-x)V2O5 where x= 30, 40 and 45 (in %mol) were prepared by the conventional melt quenching technique. Appropriate amounts of reagents: BaO (≥99.9%, P.P.H STANLAB Sp.J.) and V2O5 (≥99.9%, POCH) were thoroughly mixed in an agate mortar. The melting was...
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Quadratic Cohen representations in spectral analysis of serration process in Al–Mg alloys
PublikacjaImportant from mechanical point of view the Portevin–Le Chatelier serration phenomenon is being characterized by a complicated spectral profile. As a typical example of nonstationary processes it demands a special treatment allowing to follow the evolution of energy of stress fluctuations as a function of strain. The authors suggest the utilization of a compact system of quadratic transformations, known as Cohen class, as a technique...
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The equivariant spectral flow and bifurcation of periodic solutions of Hamiltonian systems
PublikacjaWe define a spectral flow for paths of selfadjoint Fredholm operators that are equivariant under the orthogonal action of a compact Lie group as an element of the representation ring of the latter. This G-equivariant spectral flow shares all common properties of the integer valued classical spectral flow, and it can be non-trivial even if the classical spectral flow vanishes. Our main theorem uses the G-equivariant spectral flow...
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Optimization-based antenna miniaturization using adaptively-adjusted penalty factors
PublikacjaThe continuing trend for miniaturization of electronic devices necessitates size reduction of the comprising components and circuitry. Specifically, integrated circuit-antenna modules therein require compact radiators in applications such as 5G communications, implantable and on-body devices, or internet of things (IoT). The conflict between the demands for compact size and elec-trical and field performance can be mitigated by...
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Shielded HMSIW-based frequency-tunable self-quadruplexing antenna using different solid/liquid dielectrics
PublikacjaThis article proposes a frequency-tunable self-quadruplexing antenna based on a shielded half-mode substrate integrated waveguide (S-HMSIW). In order to reduce the size of the HMSIW cavity resonator and to obtain quad-band characteristics, a modied E-shaped slot is engraved on the top of the metal. The experimental validation is carried out after analyzing the data using a circuit model. Flexibility of each resonant frequency is...
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A concept of measurement system based on the Z-Wave standard
PublikacjaIn the paper a new concept of measurement system based on the Z-Wave standard is presented. This standard is dedicated to use mainly in home automation systems, but its properties enable to use it in dispersed measurement systems and support wireless communication between measurement nodes in a mesh-type network. In the paper basic metrological aspects of the Z-Wave standard and an example of impedance measurement system are discussed.
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Resonant Conditions in a Node with an SVC Compensator
PublikacjaThe primary purpose of installing static shunt compensators in power grids is to improve the voltage conditions. Additional reactive power sources increase the system’s voltage stability and enable faster system recovery after a voltage failure. This paper presents the impact of an SVC device’s structure and settings on impedance change in the supply system, and hence on the frequencies at which resonance phenomena can develop.
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Propagation Characteristics of Partial Discharges in an Oil-Filled Power Transformer
PublikacjaPower transformers are among the most important assets in the power transmission and distribution grid. However, they suffer from degradation and possible faults causing major electrical and financial losses. Partial discharges (PDs) are used to identify the insulation health status and their degradation level. PDs are incipient, low-magnitude faults caused by localized dielectric breakdown. Those activities emit signals in many...
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Effective Permeability of Multi Air Gap Ferrite Core 3-Phase Medium Frequency Transformer in Isolated DC-DC Converters
PublikacjaThe magnetizing inductance of the medium frequency transformer (MFT) impacts the performance of the isolated dc-dc power converters. The ferrite material is considered for high power transformers but it requires an assembly of type “I” cores resulting in a multi air gap structure of the magnetic core. The authors claim that the multiple air gaps are randomly distributed and that the average air gap length is unpredictable at the...
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Study of oxygen electrode reactions on symmetrical porous SrTi0.30Fe0.70O3-δ electrodes on Ce0.8Gd0.2O1.9 electrolyte at 800 °C–500 °C
PublikacjaIron doped strontium titanates (SrTi1-xFexO3-δ) are an interesting mixed ionic-electronic conductor model used to study basic oxygen reduction/oxidation reactions. In this work, we performed an impedance spectroscopy study on symmetrical porous SrTi0.30Fe0.70O3-δ (STF70) electrodes on a ceriabased electrolyte. The sample was measured in varying oxygen concentration: from 0.3% to 100% in 800 °C - 500 °C temperature range. Low polarisation...
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Stratification of nano-pigments in anti-corrosive coatings by means of magnetic field
PublikacjaThe concept of self-stratification of coatings, although attractive, causes difficulties in its practical use, especially when pigments are added to the resins. An alternative way of obtaining a multilayer structure in a single step was presented. Using the inhomogeneous magnetic field and magnetically active components of the coating, the possibility of vertically graded differentiation of the one layer properties has been verified....
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Oxygen partial pressure and temperature dependence of Gerischer element of symmetrical porous Sr0.86Ti0.65Fe0.35O3 electrode on CGO substrate
Dane BadawczeThis dataset contains values of Gericher element at different temperatures (800 °C, 750 °C, 700 °C, 650 °C and 600 °C)and oxygen partial pressures (20%, 10%, 5%, 1%, 0.1% and 0.01% pO2) of symmetrical Sr0.86Ti0.65Fe0.35O3 electrode sintered at 1000 °C. This values were obtained by fitting each measured impedance spectra by electrical equivalent circuit...
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Oxygen partial pressure and temperature dependence of low frequency capacitance of symmetrical porous Sr0.86Ti0.65Fe0.35O3 electrode on CGO substrate
Dane BadawczeThis dataset contains values of low frequency capacitance at different temperatures (800 °C, 750 °C, 700 °C, 650 °C and 600 °C) and oxygen partial pressures (20%, 10%, 5%, 1%, 0.1% and 0.01% pO2) of symmetrical Sr0.86Ti0.65Fe0.35O3 electrode sintered at 1000 °C. This values were obtained by fitting each measured impedance spectra by electrical equivalent...
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Oxygen partial pressure and temperature dependence of middle frequency capacitance of symmetrical porous Sr0.86Ti0.65Fe0.35O3 electrode on CGO substrate
Dane BadawczeThis dataset contains values of middle frequency capacitance at different temperatures (800 °C, 750 °C, 700 °C, 650 °C and 600 °C) and oxygen partial pressures (20%, 10%, 5%, 1%, 0.1% and 0.01% pO2) of symmetrical Sr0.86Ti0.65Fe0.35O3 electrode sintered at 1000 °C. This values were obtained by fitting each measured impedance spectra by electrical equivalent...
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Oxygen partial pressure and temperature dependence of low frequency resistance of symmetrical porous Sr0.86Ti0.65Fe0.35O3 electrode on CGO substrate
Dane BadawczeThis dataset contains values of low frequency resistance at different temperatures (800 °C, 750 °C, 700 °C, 650 °C and 600 °C) and oxygen partial pressures (20%, 10%, 5%, 1%, 0.1% and 0.01% pO2) of symmetrical Sr0.86Ti0.65Fe0.35O3 electrode sintered at 1000 °C. This values were obtained by fitting each measured impedance spectra by electrical equivalent...
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Oxygen partial pressure and temperature dependence of series resistance of symmetrical porous Sr0.86Ti0.65Fe0.35O3 electrode on CGO substrate
Dane BadawczeThis dataset contains values of series resistance (R) at different temperatures (800 °C, 750 °C, 700 °C, 650 °C and 600 °C) and oxygen partial pressures (20%, 10%, 5%, 1%, 0.1% and 0.01% pO2) of symmetrical Sr0.86Ti0.65Fe0.35O3 electrode sintered at 1000 °C. This values were obtained by fitting each measured impedance spectra by electrical equivalent...
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Oxygen partial pressure and temperature dependence of middle frequency resistance of symmetrical porous Sr0.86Ti0.65Fe0.35O3 electrode on CGO substrate
Dane BadawczeThis dataset contains values of middle frequency resistance at different temperatures (800 °C, 750 °C, 700 °C, 650 °C and 600 °C) and oxygen partial pressures (20%, 10%, 5%, 1%, 0.1% and 0.01% pO2) of symmetrical Sr0.86Ti0.65Fe0.35O3 electrode sintered at 1000 °C. This values were obtained by fitting each measured impedance spectra by electrical equivalent...
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Expedited Multi-Objective Design Optimization of Miniaturized Microwave Structures Using Physics-Based Surrogates
PublikacjaIn this paper, a methodology for fast multi-objective design optimization of compact microwave circuits is presented. Our approach exploits an equivalent circuit model of the structure under consideration, corrected through implicit and frequency space mapping, then optimized by a multi-objective evolutionary algorithm. The correction/optimization of the surrogate is iterated by design space confinement and segmentation based on...
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Wideband Model Order Reduction for Macromodels in Finite Element Method
PublikacjaAbstract: This paper presents a novel algorithm for accelerating 3D Finite Element Method simulations by introducing macromodels created in local model order reduction in the selected subdomains of the computational domain. It generates the projection basis for a compact system of equations associated with a separate subdomain. Due to non-linear frequency dependency in the Right Hand Side (RHS), the standard reduction methods do...
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Multi-objective optimization for assessment of topological modification in UWB antennas
PublikacjaThis paper addresses an issue of systematic and rigorous assessment of effects of topological modifications on the performance of compact UWB antennas. Application of fast surrogate-assisted multi-objective optimization procedures allows us for obtaining, in a practically acceptable timeframe, a set of designs representing the best possible trade-offs between conflicting objectives (here, antenna size minimization and reduction...
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Reliable Greedy Multipoint Model-Order Reduction Techniques for Finite-Element Analysis
PublikacjaA new greedy multipoint model-order reduction algorithm for fast frequency-domain finite-element method simulations of electromagnetic problems is proposed. The location of the expansion points and the size of the projection basis are determined based on a rigorous error estimator. Compared to previous multipoint methods, the quality of the error estimator is significantly improved by ensuring the orthogonality of the projection...
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Elctrochemical oxidation and corrosion resistance of the Ti13Nb13Zr alloy
PublikacjaThis paper presents the results of oxidation and corrosion tests carried out on titanium alloy Ti13Nb13Zr. The oxide film was prepared by electrochemical environment 2M H3PO4 for 30 min and 1 h, at a constant voltage 40V. The tests of corrosion resistance were performed by potentiostatic method in Ringer's solution at different pH values: 7, 5 and 3. The change in an appearance of surface and the increase in corrosion resistance...
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Koncepcja i analiza sensora/aktuatora piezoelektrycznego do pomiaru procesu starzenia się ludzkiej skóry
PublikacjaNiniejszy artykuł przedstawia nową koncepcję piezoelektrycznego sensora/aktuatora przeznaczonego do pomiaru właściwości mechanicznych tkanek miękkich a w szczególności skóry ludzkiej. Wyjaśnione jest analityczne podejście z wykorzystaniem schematu zastępczego Mason’a określającego aktuator w stanie rezonansu oraz opis metody impedancji elektromechanicznej wykorzystanej w systemie pomiarowym. Analiza z użyciem metody elementów...
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3-phase medium frequency transformer for a 100kW 1.2kV 20kHz Dual Active Bridge converter
PublikacjaThe article presents a three-phase Medium Frequency Transformer being a part of a 100kW 1.2kV 20kHz Dual Active Bridge DC-DC converter. The transformer design is detailed focusing on winding and core power loss calculation. The high power three-phase MFT prototype is presented. The experimental results include the transformer impedance characteristics, no load test and three-phase DAB full load test waveforms
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Experimental and Quantum Chemical Evaluation of 8-Hydroxyquinoline as a Corrosion Inhibitor for Copper in 0.1 M HCl
PublikacjaThe corrosion inhibition properties of 8-hydroxyquinoline (8-HQ) in 0.1 M HCl for copper have been investigated by using experimental (electrochemical impedance spectroscopy (EIS), dynamic electrochemical impedance spectroscopy (DEIS), and potentiodynamic polarization) and theoretical methods complemented by surface morphological examination with the aid of scanning electron microscopy (SEM) and electron dispersive X-ray spectroscopy...
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New ceramic materials derived from pyrolyzed poly(1,2-dimethylsilazane) and starch as a potential anode for Li-ion batteries
PublikacjaNewmaterialswere obtained by pyrolysis of starch (S) and poly(1,2-dimethylsilazane) (PSN) (weight ratio: PSN/S 30/70) at temperature a) 500 °C, b) 700 °C and c) 900 °C. Ceramic materials were characterized by infrared spectroscopy, TGA, Raman spectroscopy and SEM. New Si\O and shifted Si\C stretching vibration modes emerged confirming direct interaction between silicon originating fromsilazane and oxygen coming fromstarch. The...
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Fabrication and Study of BiNbO4 Ceramics
PublikacjaAim of the present research was to fabricate and study crystalline structure as well as dielectric properties of BiNbO4 ceramics. In the present study BiNbO4 ceramics was fabricated by solid state reaction from the mixture of simple oxides viz. Bi2O3, and Nb2O5. Stoichiometric mixture of the powders was thermally analyzed so parameters of the thermal treatment were determined. The EDS measurements proved conservation of the chemical...
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Low-Profile Interdigitated UHF RFID Tag Antenna for Metallic Objects
PublikacjaThis article presents a novel miniature interdigitated ultra-high frequency (UHF) radio frequency identification (RFID) tag antenna that can be placed on metallic objects. The tag structure comprises two horizontal strip lines, each loaded with seven identical open stubs, and an integrated circuit (IC) chip connected directly to the feed lines in the middle of the structure. The perfect match to the IC chip’s impedance is realized...
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Minimal number of periodic points of smooth boundary-preserving self-maps of simply-connected manifolds
PublikacjaLet M be a smooth compact and simply-connected manifold with simply-connected boundary ∂M, r be a fixed odd natural number. We consider f, a C1 self-map of M, preserving ∂M . Under the assumption that the dimension of M is at least 4, we define an invariant Dr(f;M,∂M) that is equal to the minimal number of r-periodic points for all maps preserving ∂M and C1-homotopic to f. As an application, we give necessary and sufficient...
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Compressed Projection Bases for Model-Order Reduction of Multiport Microwave Components Using FEM
PublikacjaThis paper presents a projection basis compression technique for generating compact reduced-order models (ROM) in the FE analysis of microwave devices. In this approach redundancy is removed from the projection basis by means of the proper orthogonal decomposition technique applied to the projected system of linear equations. Compression allows for keeping the size of a reduced-order model as small as possible without compromising...
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Carbon Dioxide Recovery Skid
PublikacjaIn the face of tightening climate regulations, the adoption of carbon dioxide recovery systems is inevitable. Modular process skid units have been widely adopted across the industry. The gas-steam power plant skid unit with the carbon dioxide recovery system was described. The proposed skid module consists of the compact cycle with the oxy-combustion and the carbon dioxide capture skid unit producing pure compressed CO2. The compactness...
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Multi-transformer primary-side regulated flyback converter for supplying isolated IGBT and MOSFET drivers
PublikacjaThis paper presents primary-side voltage regulated multi-transformer quasi-resonant flyback converter (MTFC) for supplying isolated power switch drivers. The proposed topology offers distinct advantages over frequently used flyback converter possessing one high frequency transformer with isolated multiple outputs. Particularly, when a large number of separate dc supply units is required, then MTFC enables improved regular distribution...
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Selection of C-Type Filters for Reactive Power Compensation and Filtration of Higher Harmonics Injected into the Transmission System by Arc Furnaces
PublikacjaThis article presents a method for selecting the elements of a C-type filter working with a conventional LC-type filter for compensating reactive power and filtering out higher harmonics generated by arc furnaces and ladle furnaces. The study was conducted in a steel mill supplied by a 110 kV transmission system, where higher harmonic currents and nonlinear loads were measured. A series of computer simulations were performed under...
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Database of the minimal sets of Lefschetz periods for Morse-Smale diffeomorphisms of a connected sum of g tori
Dane BadawczeMorse–Smale diffeomorphisms, structurally stable and having relatively simple dynamics, constitute an important subclass of diffeomorphisms that have been carefully studied during past decades. For a given Morse–Smale diffeomorphism one can consider “Minimal set of Lefschetz periods”, which provides the information about the set of periodic points of...
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A novel concept for tissue-metal detection and differentiation using an inductive proximity sensor
PublikacjaIn this paper a novel application of inductive proximity sensors for detection of living tissue by means of measurements of the coil impedance changes at different frequencies is described. The mathematical analyses utilizing Bessel function estimation include detected object size and its distance from a sensor. The main aim of this study is to prove the possibility of distinguishing between metal objects and living tissues. The...
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Domain Reduction in Hybrid Technique for Electromagnetic Wave Scattering Problems
PublikacjaThis paper proposes a combination of the field matching technique, finite element method and generalized impedance matrix, the main idea of which is to reduce the computational domain by surrounding a scatterer with the smallest convex shape and applying the field matching technique. This approach can be applied for arbitrary shaped scatterers and types of materials and allows for the reduction of the computational domain. In order...