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Wyniki wyszukiwania dla: ELECTROMAGNETIC TRANSIENTS
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Electromagnetic Modeling of Microstrip Elements Aided with Artificial Neural Network
PublikacjaThe electromagnetic modeling principle aided withartificial neural network to designing the microwave widebandelements/networks prepared in microstrip technology is proposedin the paper. It is assumed that the complete information is knownfor the prototype design which is prepared on certain substratewith certain thickness and electric permittivity. The longitudinaland transversal dimensions of new design...
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Signal propagation in electromagnetic media described by fractional-order models
PublikacjaIn this paper, signal propagation is analysed in electromagnetic media described by fractional-order (FO) models (FOMs). Maxwell’s equations with FO constitutive relations are introduced in the time domain. Then, their phasor representation is derived for one-dimensional case of the plane wave propagation. With the use of the Fourier transformation, the algorithm for simulation of the non-monochromatic wave propagation is introduced....
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Intergranular Corrosion Detection Using Electromagnetic Transducers for Ultrasonic Testing
PublikacjaThe aim of this paper is to create a research methodology that allows a quick analysis of the structural state of high alloy austenitic steels using non-destructive ultrasonic tests, in contrast to destructive standard methods. Electromagnetic acoustic transducers (EMAT) are used to generate and receive the ultrasonic wave and detect the microstructural changes caused by sample sensitization in elevated temperature, even after...
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Electromagnetic Field Measurements of Bow Thruster Drive with Frequency Converter
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Concept of Compatibility Region for the Evaluation of IR UWB Electromagnetic Compatibility
PublikacjaThis paper presents a new proposal for the unified evaluation of ultra wideband and narrowband radio communication systems electromagnetic compatibility, called “compatibility region”. The idea of compatibility region is based on the relation between the ratio of narrowband to ultra wideband signal power in a receiver and some transmission quality indicators (bit error rate, effective data rate).
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Thermodynamic and electromagnetic properties of hard-core charged bosons on a lattice
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Determination of the impact indicators of electromagnetic interferences on computer information systems
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Electromagnetic curtain effect and tunneling properties of multilayered periodic structures
PublikacjaArtykuł przedstawia analizę rozpraszania fali elektromagnetycznej na wielowarstwowych strukturach periodycznych. W analizowanych strukturach zaobserwowano efekt tunelowania fali oraz efekt przestrajania pasm zaporowych/przepustowych (efekt kurtyny elektromagnetycznej)
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Nonlinear evolution of components of electromagnetic field of helicoidal wave in plasma
PublikacjaWyprowadzilismy model równań opisujących oddziaływanie pomiedzy kołowo spolaryzowanymi paczkami fal helikoidalnych w dwuwymiarowej plazmie. Dla quasi-jednowymiarowego przypadku otrzymaliśmy warunek nieliniowego rezonansu dla oddziaływania N-fal. Nowym ''osiągnięciem'' badań w kontekscie teorii solitonów, jest znalezienie rozwiązań dla przypadku asynchronizmu fal, które wydaje się być podstawowym dla paczek falowych nachylonych...
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Model of the double-rotor induction motor in terms of electromagnetic differential
PublikacjaThe 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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Effect of mesh deformation on the accuracy of 3D FEM electromagnetic analysis
PublikacjaIn this paper, the accuracy of 3D FEM electromagnetic simulations in parametric analysis using mesh deformation techniques is discussed. Mesh deformation techniques allow one to preserve the mesh topology while the geometry is changed. It is shown that the application of mesh deformation can provide accurate simulation results even for very large deformations. On the other hand, it is also shown that the technique has to be used...
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Electromagnetic properties of a dielectric slab with an embedded silver nanowire grating
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Electromagnetic characterization of a silver nanowire grating embedded into a dielectric slab
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Calculation methods of interaction of electromagnetic waves with objects of complex geometries
PublikacjaModeling of the electromagnetic interaction with different homogeneous or inhomo-geneous objects is a fundamental and important problem. It is relatively easy to solve Maxwellequations analytically when the scattering object is spherical or cylindrical, for example. How-ever, when it loses these properties all that is left for us is to useapproximation models, to ac-quire the solution we need. Modeling of complex, non-spherical,...
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Electromagnetic Simulations with 3D FEM and Intel Optane Persistent Memory
PublikacjaAbstract—Intel Optane persistent memory has the potential to induce a change in how high-performance calculations requiring a large system memory capacity are conducted. This article presents what this change may look like in the case of factorization of large sparse matrices describing electromagnetic problems arising in the 3D FEM analysis of passive highfrequency components. In numerical tests, the Intel oneAPI MKL PARDISO was...
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Reliability of acicular grindable thermocouples for transient temperature measurements at sliding contacts
PublikacjaAcicular grindable thermocouples represent an interesting and prospective technique of temperature measurements at sliding contacts. This study aimed at the investigation of their reliability and accuracy as applied to the friction materials of various classes in contact with steel. The tests were conducted on a pin-on-disc tribometer under stationary and transient regimes. The experimental results were validated by comparing the...
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Type III Responses to Transient Inputs in Hybrid Nonlinear Neuron Models
PublikacjaExperimental characterization of neuronal dynamics involves recording both of spontaneous activity patterns and of responses to transient and sustained inputs. While much theoretical attention has been devoted to the spontaneous activity of neurons, less is known about the dynamic mechanisms shaping their responses to transient inputs, although these bear significant physiological relevance. Here, we study responses to transient...
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Model of the reciprocating engine using iterative procedures of the transient torque calculation
PublikacjaPrzedstawiony w pracy model silnika spalinowego uzależnia wartość dynamicznego momentu od sygnału sterowania po skokowej zmianie nastawy oraz od historii dynamicznej silnika i czasu jaki upłynął od tej zmiany. Przedstawione wyniki badań potwierdzają zasadność takiego opisu modelowanego zjawiska. Można również zauważyć, że po pewnym czasie od chwili rozpoczęcia procesu rozpędzania przebieg momentu dynamicznego będzie przebiegał...
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An Experimental Investigation of Pressure Wave Celerity During the Transient Slurry Flow
PublikacjaTransportation of slurries in pressure pipelines is an example of a complex flow due to specific parameters of transported medium. For practitioners, the economy of designing and maintenance is usually the most important factor. For this reason, most of hydrotransport installations are fairly simple; however, they become more vulnerable to negative effects of the transient flow which can occur in pressure pipelines. As the consequence,...
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Simulation of the remanence influence on the transient states in a single-phase multiwinding transformer
PublikacjaThis paper presents the mathematical model of a single-phase multi-winding core type transformer taking into account magnetic hysteresis phenomenon based on the feedback Preisach model (FPM). The set of loop differential equations was developed for a K-th winding transformer model where the flux linkages of each winding includes flux Φ common to all windings as a function of magneto motive force Θ of all windings. The first purpose...
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Recent and Emerging Applications of Graphene-based metamaterials in Electromagnetics
PublikacjaSurface Plasmon Polaritons (SPPs) operating in mid-infrared up to terahertz (THz) frequencies have been traditionally manufactured on expensive metals such as gold, silver, etc. However, such metals have poor surface confinement that limits the optical applications of SPPs. The invention of graphene is a breakthrough in plasmon-based devices in terms of design, fabrication and applications, thanks to its plasmonic wave distribution,...
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On possible applications of media described by fractional-order models in electromagnetic cloaking
PublikacjaThe purpose of this paper is to open a scientific discussion on possible applications of media described by fractional-order (FO) models (FOMs) in electromagnetic cloaking. A 2-D cloak based on active sources and the surface equivalence theorem is simulated. It employs a medium described by FOM in communication with sources cancelling the scattered field. A perfect electromagnetic active cloak is thereby demonstrated with the use...
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A Model-Order Reduction Approach for Electromagnetic Problems With Nonaffine Frequency Dependence
PublikacjaThe aim of this paper is to present a novel model-order reduction (MOR) technique for the efcient frequency-domain nite-element method (FEM) simulation of microwave components. It is based on the standard reduced-basis method, but the subsequent expansion frequency points are selected following the so-called sparsied greedy strategy. This feature makes it especially useful to perform a fast-frequency sweep of problems that lead...
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Signal Propagation in Electromagnetic Media Modelled by the Two-Sided Fractional Derivative
PublikacjaIn this paper, wave propagation is considered in a medium described by a fractional-order model, which is formulated with the use of the two-sided fractional derivative of Ortigueira and Machado. Although the relation of the derivative to causality is clearly specified in its definition, there is no obvious relation between causality of the derivative and causality of the transfer function induced by this derivative. Hence, causality...
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Time domain model of the resonance-based electromagnetic pulses emission system
PublikacjaIn the literature, the emission properties of the electromagnetic field pulse systems based on high voltage antennas (HVR) have been widely described. In order to increase the emission efficiency by extending duration and increasing amplitude of the impulse it is possible to use a resonance system tuned to the parameters of the signal shaped in the pulse forming circuit. The synthesis of a time-domain simulation model of a complex...
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Metamaterial-Based Sub-Microwave Electromagnetic Field Energy Harvesting System
PublikacjaThis paper presents the comprehensive analysis of the sub-microwave, radio frequency band resonant metastructures’ electromagnetic properties with a particular emphasis on the possibility of their application in energy harvesting systems. Selected structures based on representative topologies of metamaterials have been implemented in the simulation environment. The models have been analyzed and their substitute average electromagnetic...
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The influence of electromagnetic pollution on living organisms – historical trends and forecasting changes
PublikacjaCurrent technologies have become a source of omnipresent electromagnetic pollution from generated electromagnetic fields and resulting electromagnetic radiation. In many cases this pollution is much stronger than any natural sources of electromagnetic fields or radiation. Wireless and radio communication, electric power transmission or devices in daily use such as smartphones, tablets and portable computers every day expose people...
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Modeling of Process of Maintenance of Transport Systems Telematics with Regard to Electromagnetic Interferences
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Modelling the Safety Levels of ICT Equipment Exposed to Strong Electromagnetic Pulses
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Reliability-Operational Analysis of the LED Lighting Module Including Electromagnetic Interference
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Electromagnetic wave scattering from material objects using hybrid methods
PublikacjaRozdział zawiera opis hybrydowych metod analizy stanowiących połączenie metody różnic skończonych w dziedzinie częstotliwości (FDFD) z metodą dopasowania rodzajów (MM), służących do badania cylindrycznych struktur falowych w układach zamkniętych i otwartych.
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Viscous versus electromagnetic damping – amplification in a neighbourhood of a mechanism singular position
PublikacjaIn the paper, damping of vibrations are considered and compared in a mechanical and in a electromechanical system. In the system, a continuous beam is considered as the main vibrating element. The compared dissipations methods are based on: viscous dampers and DC generators. To increase the possible damping effectiveness, velocity amplification is proposed, i.e., a mechanism is introduced between the beam and the damping element....
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The ring propeller with conical electromagnetic bearings and magneto fluid sealing system.
PublikacjaW przedstawionej koncepcji nowego zespołu napędowego najbardziej znamiennym rozwiązaniem jest zastosowanie nowoczesnych łożysk elektromagnetycznych dla pędnika śrubowego w prototypowej wersji silnika pierścieniowego synchronicznego z magnesami z ziem rzadkich. W artykule przedstawiono konstrukcję stożkowych łożysk magnetycznych. Technika uszczelniania cieczami magnetycznymi jest nową koncepcją pozwalającą na rozwiązywanie wielu...
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Electromagnetic wave scattering by a set of axially symmetric omega-medium cylinder
PublikacjaZaprezentowano analizę rozproszenia fali elektromagnetycznej od układu obiektów cylindrycznych zbudowanych z materiałów pseudochiralnych, umieszczonych w złączach falowodowych lub wolnej przestrzeni. Analiza bazuje na iteracyjnej procedurze rozproszenia i metodzie dopasowania rodzajów.
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A time-frequency method for detection of electromagnetic field interference on metal constructions.
PublikacjaPrzedstawiono metodę detekcji oddziaływania pola elektromagnetycznego na metalowe konstrukcje podziemne. Polega ona na czasowo-częstotliwościowej analizie rejestrów zmian potencjału źródła pola (np. prądów błądzących) oraz potencjału konstrukcji podziemnej, z wykorzystaniem krótkoczasowej transformaty Fouriera STFT. Wnioski o oddziaływaniu pola na konstrukcję metalową wyciąga się na podstawie analizy uzyskanych widm.
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Electromagnetic interference frequencies prediction model of flyback converter for snubber design
PublikacjaSnubber design for flyback converters usually requires experimental prototype measurements or simulation based on accurate and complex models. In this study simplified circuit modelling of a flyback converter has been described to dimension snubbers in early stage of design process. Simulation based prediction of the transistor and diode ringing frequencies has been validated by measurements in a prototype setup. In that way obtained...
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A systematic review on cellular responses of Escherichia coli to nonthermal electromagnetic irradiation
PublikacjaInvestigation of Escherichia coli under electromagnetic fields is of significance in human studies owing to its short doubling time and human‐like DNA mechanisms. The present review aims to systematically evaluate the literature to conclude causality between 0 and 300 GHz electromagnetic fields and biological effects in E. coli. To that end, the OHAT methodology and risk of bias tool were employed. Exponentially growing cells exposed...
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Time-domine Dipole Fields in acoustic and Elektromagnetics
PublikacjaThe ultrawideband (UWB) radio technique presents a challenge not just for technology. The UWB carrier-free pulses act at a close distance, their electromagnetic fields being very different from classic monochromatic plane wave. The author proposes to adapt a time-domian approach to analysis of broadband spherical fields, both acoustic and electromagnetic, in fundamental cases of quasi-point physical sources.
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Climatology of Transient Luminous Events and Lightning Observed Above Europe and the Mediterranean Sea
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Transient torsional vibrations control in the geared drive trains of the hot rolling mills
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Modeling of Transient Photocurrent in Organic Semiconductors Incorporating the Annihilation of Excitons on Charge Carriers
PublikacjaThe role of the annihilation of excitons on charge carriers has been theoretically investigated in organic semiconductors. We have developed the numerical drift-diffusion model by incorporation terms which describe the annihilation process. The transient photocurrent has been calculated for different injection barrier heights, exciton mobilities, and annihilation rate constants. We have demonstrated that the annihilation has a...
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Spurious Modes in Model Order Reduction in Variational Problems in Electromagnetics
PublikacjaIn this work, we address an everlasting issue in 2 model order reduction (MOR) in electromagnetics that has 3 remained unnoticed until now. Contrary to what has been 4 previously done, we identify for the very first time spurious 5 modes in MOR for time-harmonic Maxwell’s equations and 6 propose a methodology to remove their negative influence on the 7 reduced order model (ROM) response. These spurious modes 8 have nonzero resonance...
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Reduced order models in computational electromagnetics (in memory of Ruediger Vahldieck)
PublikacjaThis paper reviews research of Ruediger Vahldieck's group and the group at the Gdansk University of Technology in the area of model order reduction techniques for accelerating full-wave simulations. The applications of reduced order models to filter design as well as of local and nested(multilevel) macromodels for solving 3D wave equations and wave-guiding problems using finite difference and finite element methods are discussed.
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Multimodal Genetic Algorithm with Phase Analysis to Solve Complex Equations of Electromagnetic Analysis
PublikacjaIn this contribution, a new genetic-algorithm-based method of finding roots and poles of a complex function of a complex variable is presented. The algorithm employs the phase analysis of the function to explore the complex plane with the use of the genetic algorithm. Hence, the candidate regions of root and pole occurrences are selected and verified with the use of discrete Cauchy's argument principle. The algorithm is evaluated...
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Diagonalized Macromodels in Finite Element Method for Fast Electromagnetic Analysis of Waveguide Components
PublikacjaA new technique of local model-order reduction (MOR) in 3-D finite element method (FEM) for frequency-domain electromagnetic analysis of waveguide components is proposed in this paper. It resolves the problem of increasing solution time of the reduced-order system assembled from macromodels created in the subdomains, into which an analyzed structure is partitioned. This problem becomes particularly relevant for growing size and...
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Influence of electric, magnetic and electromagnetic fields on the circadian system – current stage of knowledge
PublikacjaOne of the side effects of each electrical device work is the electromagnetic field generated near its workplace. All organisms, including humans, are exposed daily to the influence of different types of this field, characterized by various physical parameters. Therefore, it is important to accurately determine the effects of an electromagnetic field on the physiological and pathological processes occurring in cells, tissues and...
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Galvanic isolation circuit for measuring systems operating in environments with strong electromagnetic disturbances
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Issue of Assessment of the Strong Electromagnetic Pulses Impact on the Functioning of Selected Electronic Devices
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Determination of Safety Levels of Electronic Devices Exposed to Impact of Strong Electromagnetic Pulses
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The Reliability and Operational Analysis of ICT Equipment Exposed to the Impact of Strong Electromagnetic Pulses
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