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Search results for: ELECTROMAGNETIC FIELDS (EMFS)
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Communication and Load Balancing Optimization for Finite Element Electromagnetic Simulations Using Multi-GPU Workstation
PublicationThis paper considers a method for accelerating finite-element simulations of electromagnetic problems on a workstation using graphics processing units (GPUs). The focus is on finite-element formulations using higher order elements and tetrahedral meshes that lead to sparse matrices too large to be dealt with on a typical workstation using direct methods. We discuss the problem of rapid matrix generation and assembly, as well as...
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Compact Electromagnetic Lens Antennas Using Cascaded Metasurfaces for Gain Enhancement and Beam Steering Applications
PublicationElectromagnetic (EM) lens antenna designs using cascaded metasurfaces for gain enhancement and beam steering applications are proposed. Two different lens aperture designs are proposed and populated with aperiodic unit cells of size 0.2λo × 0.2λo. In lens Design 1, the unit cells of different phases are distributed in concentric circular zones, whereas in lens Design 2, the unit cells of different phases are distributed in vertical...
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Surrogate modeling of impedance matching transformers by means of variable‐fidelity electromagnetic simulations and nested cokriging
PublicationAccurate performance evaluation of microwave components can be carried out using full‐wave electromagnetic (EM) simulation tools, routinely employed for circuit verification but also in the design process itself. Unfortunately, the computational cost of EM‐driven design may be high. This is especially pertinent to tasks entailing considerable number of simulations (eg, parametric optimization, statistical analysis). A possible...
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Greedy Multipoint Model-Order Reduction Technique for Fast Computation of Scattering Parameters of Electromagnetic Systems
PublicationThis paper attempts to develop a new automated multipoint model-order reduction (MOR) technique, based on matching moments of the system input–output function, which would be suited for fast and accurate computation of scattering parameters for electromagnetic (EM) systems over a wide frequency band. To this end, two questions are addressed. Firstly, the cost of the wideband reduced model generation is optimized by automating a...
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Comparison of EFD and CFD investigation of velocity fields for selected body-propeller configurations
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Comparison of EFD and CFD investigation of velocity fields for selected body-propeller configurations
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Propagation in a ferrite cylindrical waveguide magnetized by a two four-pole magnetic fields.
PublicationUżywając metody rodzajów sprzężonych rozwiązano zagadnienie ferrytowego falowodu cylindrycznego magnesowanego poprzecznie w układzie elektronicznie obracanego czterobiegunowego pola magnetycznego. W falowodzie występuje zjawisko dwójłomności i przesunięcia fazy. Badano zmiany stanu polaryzacji fali elektromagnetycznej na wyjściu falowodu o różnej długości. Wyniki wykorzystano do zaprojektowania sekcji półfalowej falowodu, w której...
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Two-photon double ionization of atoms in attosecond x-ray radiation fields
PublicationWe consider two-photon double ionization of helium with 100, 200, and 400 eV excess energy for the two ejected electrons, corresponding to photon energies of 89.5, 139.5, and 239.5 eV, respectively. We focus on the case of ultrashort pulses (two oscillations of the field) and develop an approach to calculate the two-photon transition matrix elements within the lowest order of the time-dependent perturbation theory. One of the...
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Domain Reduction in Hybrid Technique for Electromagnetic Wave Scattering Problems
PublicationThis 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...
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Nonlinear evolution of components of electromagnetic field of helicoidal wave in plasma
PublicationWyprowadzilismy 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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Electromagnetic Field Measurements of Bow Thruster Drive with Frequency Converter
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Thermodynamic and electromagnetic properties of hard-core charged bosons on a lattice
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Electromagnetic curtain effect and tunneling properties of multilayered periodic structures
PublicationArtykuł 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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Determination of the impact indicators of electromagnetic interferences on computer information systems
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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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Scalability of surrogate-assisted multi-objective optimization of antenna structures exploiting variable-fidelity electromagnetic simulation models
PublicationMulti-objective optimization of antenna structures is a challenging task due to high-computational cost of evaluating the design objectives as well as large number of adjustable parameters. Design speedup can be achieved by means of surrogate-based optimization techniques. In particular, a combination of variable-fidelity electromagnetic (EM) simulations, design space reduction techniques, response surface approximation (RSA) models,...
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Group-9 Transition-Metal Suboxides Adopting the Filled-Ti2Ni Structure: A Class of Superconductors Exhibiting Exceptionally High Upper Critical Fields
PublicationTi2Ni and the related η-carbide structure are known to exhibit various intriguing physical properties. The Ti2Ni structure with the cubic space group Fd3̅m is surprisingly complex, consisting of a unit cell with 96 metal atoms. The related η-carbide compounds correspond to a filled version of the Ti2Ni structure. Here, we report on the structure and superconductivity in the η-carbide-type suboxides Ti4M2O with M = Co, Rh, and Ir....
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On Accelerated Metaheuristic-Based Electromagnetic-Driven Design Optimization of Antenna Structures Using Response Features
PublicationDevelopment of present-day antenna systems is an intricate and multi-step process requiring, among others, meticulous tuning of designable (mainly geometry) parameters. Concerning the latter, the most reliable approach is rigorous numerical optimization, which tends to be re-source-intensive in terms of computing due to involving full-wave electromagnetic (EM) simu-lations. The cost-related issues are particularly pronounced whenever...
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Low-Cost Quasi-Global Optimization of Expensive Electromagnetic Simulation Models by Inverse Surrogates and Response Features
PublicationConceptual design of contemporary high-frequency structures is typically followed by a careful tuning of their parameters, predominantly the geometry ones. The process aims at improving the relevant performance figures, and may be quite expensive. The reason is that conventional design methods, e.g., based on analytical or equivalent network models, often only yield rough initial designs. This is especially the case for miniaturized...
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Fungal L-Methionine Biosynthesis Pathway Enzymes and Their Applications in Various Scientific and Commercial Fields
PublicationL-methionine (L-Met) is one of the nine proteinogenic amino acids essential for humans since, in human cells, there are no complete pathways for its biosynthesis from simple precursors. L-Met plays a crucial role in cellular function as it is required for proper protein synthesis, acting as an initiator. Additionally, this amino acid participates in various metabolic processes and serves as a precursor for the synthesis of S-adenosylmethionine...
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Estimation of nitrogen leaching load from agricultural fields in the Puck Commune with an interactive calculator
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Ab initio and experimental studies of polarization and polarization related fields in nitrides and nitride structures
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Application of Rotating Magnetic Fields Increase the Activity of Antimicrobials Against Wound Biofilm Pathogens
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Phytotechnology applied to municipal wastewater treatment on irrigated fields of Gdansk (Poland) (1872-1992)
PublicationPola nawadniane ściekami w Gdańsku zbudowane zostały w roku 1872 i pracowały do roku 1992. Obejmowały one 320 ha piasków nadmorskich w miejscowości Gdansk Sianki, między Wisloujściem a Stogami. Obciążenie hydrauliczne pól wynosiło początkowqo 3000 mm rocznie, ale stopniowo wzrastało aż do poziomu 8000 mm rocznie. Pola pokryte były monokulturą trawiasta złożoną głównie z perzu, a zagłębieniach terenowych występowała głównie pokrzywa....
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A time-frequency method for detection of electromagnetic field interference on metal constructions.
PublicationPrzedstawiono 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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The ring propeller with conical electromagnetic bearings and magneto fluid sealing system.
PublicationW 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
PublicationZaprezentowano 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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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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Viscous versus electromagnetic damping – amplification in a neighbourhood of a mechanism singular position
PublicationIn 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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Electromagnetic wave scattering from material objects using hybrid methods
PublicationRozdział 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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Electromagnetic interference frequencies prediction model of flyback converter for snubber design
PublicationSnubber 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 Model-Order Reduction Approach for Electromagnetic Problems With Nonaffine Frequency Dependence
PublicationThe 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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IEEE Letters on Electromagnetic Compatibility Practice and Applications
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Reduced-cost electromagnetic-driven optimisation of antenna structures by means of trust-region gradient-search with sparse Jacobian updates
PublicationNumerical optimisation plays more and more important role in the antenna design. Because of lack of design-ready theoretical models, electromagnetic (EM)-simulation-driven adjustment of geometry parameters is a necessary step of the design process. At the same time, traditional parameter sweeping cannot handle complex topologies and large number of design variables. On the other hand, high computational cost of the conventional...
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Simulations of wave propagation and attenuation in fields of colliding ice floes
Open Research DataThis dataset contains results of numerical smulations of sea ice-wave interactions, corresponding to laboratory experiments conducted at the Large Ice Model Basin (LIMB) at the Hamburg Ship Model Basin (HSVA) as part of the LS-WICE ("Loads on Structure and Waves in Ice"; https://zenodo.org/record/1067170#.XrLt_dhpxhE) project. THe simulations were conducted...
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Wave energy attenuation in fields of colliding ice floes. Part B: A laboratory case study
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Air bubble and oil droplet interactions in centrifugal fields during air-sparged hydrocyclone flotation
PublicationWzajemne oddziaływania pęcherzyka powietrza i kropli oleju w polu siły odśrodkowej były rozpatrywane w odniesieniu do warunków procesowych obecnych podczas flotacji za pomocą hydrocyklonu. Efektywności zetknięcia się kropli oleju z pęcherzykami powietrza zostały zidentyfikowane jako znacząco mniejsze w porównaniu do efektywności zetknięcia się cząstek minerałów. Wyznaczono czasy zderzenia i styku ślizgowego. Chociaż przyczepność...
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Adaptive Method for Modeling of Temporal Dependencies between Fields of Vision in Multi-Camera Surveillance Systems
PublicationA method of modeling the time of object transition between given pairs of cameras based on the Gaussian Mixture Model (GMM) is proposed in this article. Temporal dependencies modeling is a part of object re-identification based on the multi-camera experimental framework. The previously utilized Expectation-Maximization (EM) approach, requiring setting the number of mixtures arbitrarily as an input parameter, was extended with the...
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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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The Issue of Operating Security Systems in Terms of the Impact of Electromagnetic Interference Generated Unintentionally
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Reliability analysis of aerodrome’s electronic security systems taking into account electromagnetic interferences
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Galvanic isolation circuit for measuring systems operating in environments with strong electromagnetic disturbances
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Electromagnetic forced vibrations of composite nanoplates using nonlocal strain gradient theory
PublicationThis article is intended to analyze forced vibrations of a piezoelectric-piezomagnetic ceramic nanoplate by a new refined shear deformation plate theory in conjunction with higher-order nonlocal strain gradient theory. As both stress nonlocality and strain gradient size-dependent effects are taken into account using the higher-order nonlocal strain gradient theory, the governing equations of the composite nanoplate are formulated....
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IEEE Electromagnetic Compatibility Magazine
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Scale-consistent approach to the derivation of coarse-grained force fields for simulating structure, dynamics, and thermodynamics of biopolymers
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Analysis of electromagnetic plane wave scattering from 2-d periodic arrangements of posts
PublicationArtykuł prezentuje metodę analizy rozpraszania fali elektromagnetycznej od układu periodycznie rozłożonych obiektów cylindrycznych na płaszczyźnie. Opisywane podejście analizy wykorzystuje pełnofalowe rozwiązanie oparte na metodzie dopasowania rodzajów. Wynikiem analizy jest wielorodzajowa macierz rozproszenia badanych powierzchni periodycznych.