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Search results for: SUPERCONDUCTING ELECTROMAGNETS
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Impact of eddy currents on Barkhausen and magnetoacoustic emission intensity in a steel plate magnetized by a C-core electromagnet.
PublicationZbadano (zmierzono i modelowano metodą elementów skończonych) wpływ częstości magnesowania na przestrzenny i czasowy rozkład indukcji magnetycznej wewnątrz płyty stalowej. Wyznaczono i zmierzono natężenie polowego rozkładu Barkhausena (HEB) na powierzchni płyty oraz natężnie emisji magnetoakustycznej (EMA) z całej magnesowanej objętości. Wykazano, iż obserwowane zmiany w natężeniu HEB i EMA są wynikiem zmian w rozkładzie indukcji...
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IEEE Journal of Electromagnetics, RF and Microwaves in Medicine and Biology
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Multilevel model order reduction with generalized compression of boundaries for 3-d FEM electromagnetic analysis
PublicationThis paper presents a multilevel Model Order Reduction technique for a 3-D electromagnetic Finite Element Method analysis. The reduction process is carried out in a hierarchical way and involves several steps which are repeated at each level. This approach brings about versatility and allows one to efficiently analyze complex electromagnetic structures. In the proposed multilevel reduction the entire computational domain is covered...
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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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Low Frequency Electromagnetic Interferences Impact on Transport Security Systems Used in Wide Transport Areas
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Selected issues regarding the reliability-operational assessment of electronic transport systems with regard to electromagnetic interference
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The Impact of Strong Electromagnetic Pulses on the Operation Process of Electronic Equipment and Systems Used in Intelligent Buildings
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Intensification of bacterial cellulose production process with sequential electromagnetic field exposure aided by dynamic modelling
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Should we publish in Chinese? –answers exemplified by articles on OSH and electromagnetism indexed in selected databases
PublicationThe article addresses the issues of scientific communication, including the indexing of articles in international databases (Web of ScienceCC, Scopus) and Chinese institutions, including technical universities. One of the important issues in assessing the quality of a scientist's work is the...
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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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Protective and Suppressing Electromagnetic Interference Properties of Epoxy Coatings Containing Nano-Sized NiZn Ferrites
PublicationNano-crystalline ferrites with the chemical formula NixZn(1−x)Fe2O4, where x = 0, 0.2, 0.4, 0.6, 0.8, 1.0, were synthesized using a co-precipitation method. The obtained ferrites were investigated by X-ray diffraction (XRD). The corrosion inhibiting behavior of nano-sized ferrites was tested using carbon steel samples and 10% aqueous ferrite extracts. Results were compared with previous data obtained for micro-sized ceramic ferrites....
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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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Comments on ''An innovative fast powerful method for tackling electromagnetic eigenvalue problems for multistrip transmission lines''
PublicationPraca stanowi komentarz do publikacji Casanuevy i Garcii dotyczącej techniki szybkiego obliczania charakterystyk dyspersyjnych falowodów z niejednorodnym wypełnieniem. Zwrócono uwagę na niepotrzebną komplikację zagadnienia poprzez zastosowanie techniki rozkładu na wartości szczególne.
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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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The Assessment of the Influence of Low-Frequency Electromagnetic Fields Originated from the Power Infrastructure on Humans’ Health
PublicationThe objective of this study is to assess the impact of low-frequency electromagnetic fields (LF EMFs) generated by power infrastructure on the nearby environment. Measurements of electric (E) and magnetic (H) field intensities were conducted around high-voltage power lines, transformer stations and facilities related to them. Numerical simulations were also performed to model the distribution of the field values around real buildings...
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Otrzymywanie makroskopowego kompozytu nadprzewodząco-ferromagnetycznego na bazie YBa2Cu3O7-x = Obtaining the macroscopic superconductive ferromagnetic composite based on YBa2Cu3O7-x
PublicationPublikacja przedstawia technologię otrzymywania kompozytów nadprzewodząco-ferromagnetycznych na bazie porowatego ceramicznego nadprzewodnika wysokotemperaturowego YBCO o porach otwartych.
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Scattering by parallel cylindrical posts with conducting strips. W: Pro- gress in electromagnetics research. Ed. J.A. Kong. Cambridge, Massachusett/ USA/: EMW Publ.**2003 s. 305-333, 18 rys. 5 tabl. bibliogr. 14 poz. Electromagnetic Waves. PIER [nr] 43. Rozpraszanie na równoległych metalizowanych obiektach cylindrycznych.
PublicationRozwinięto teorię rozpraszania fali elektromagnetycznej w obszarach otwar-tych i zamkniętych na metalizowanych obiektach cylindrycznych przy użyciuzmodyfikowanej procedury iteracyjnej i metody dopasowania rodzajów. W wynikuanalizy uzyskano pole rozproszone w przypadku struktur otwartych oraz odpo-wiedzi częstotliwościowe współczynników odbicia i transmisji w prostokąt-nych złączach falowodowych. Obrót i przemieszczenie...
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Local response surface approximations and variable-fidelity electromagnetic simulations for computationally efficient microwave design optimisation
PublicationIn this study, the authors propose a robust and computationally efficient algorithm for simulation-driven design optimisation of microwave structures. Our technique exploits variable-fidelity electromagnetic models of the structure under consideration. The low-fidelity model is optimised using its local response surface approximation surrogates. The high-fidelity model is refined by space mapping with polynomial interpolation of...
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Numerical Comparison of Damping Amplification Effects Obtained in Neighborhood of a Mechanism Singular Position - Viscous and Electromagnetic Cases
PublicationIn the paper, results of numerical investigations are presented. A continuous beam is considered as the main vibrating element. Two energy dissipations methods are compared: viscous dampers and DC generators. To increase the damping effectiveness, velocity amplification is proposed, i.e., a mechanism is introduced between the beam and the damping element, and the mechanism configuration is set as closed to the singular position...
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INTERLABORATORY COMPARISON OF THE ELECTROMAGNETIC EMISSION MEASUREMENTS USING FAR AND GTEM TEST SITES UP TO 1 GHz
PublicationElectromagnetic emission limiting is one of the basic requirements in the European Directive 2014/30/EU (EMC Directive). Manufacturers often use alternative methods of measurements to make preliminary verification of emission. This paper presents and analyzes problem with comparison between measurements in different test sites: FAR (Fully Anechoic Room) and GTEM (Gigahertz Transverse Electromagnetic cell). FAR is assumed as the...
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Mechanisms positioned in a neighbourhood of their singular positions - velocity amplification in the electromagnetic damping. Part 2. Numerical Verification
PublicationPraca prezentuje zagadnienia występujące podczas elektromagnetycznego tłumienia drgań układów mechanicznych. Analizowano zachowania układu ciągłego i jego drgania. Aby przyśpieszyć tłumienie, wprowadzono specjalny dwuramienny mechanizm umieszczony pomiędzy elementem drgającym i elementem tłumiącym drgania. Mechanizm ustawiony jest w pobliżu swojego ustawienia osobliwego. Aby określić potencjalny kierunek zmian prowadzący do poprawić...
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Issue of reliability–exploitation evaluation of electronic transport systems used in the railway environment with consideration of electromagnetic interference
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Electromagnetic plane wave scattering from a cylindrical object with an arbitrary cross section using a hybrid technique
PublicationA hybrid technique combining finite-element and mode-matching methods for the analysis of scattering problems in open and closed areas is presented. The main idea of the analysis is based on the utilization of the finite-element method to calculate the post impedance matrix and combine it with external excitation. The discrete analysis, which is the most time- and memory-consuming, is limited here only to the close proximity of...
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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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Electromagnetic Field Associated With Dermoscope Magnets May Affect the Safety of Cardiac Implanted Electronic Devices Patients
PublicationDermoscopy is currently used as an auxiliary tool in general dermatology. Since some commercially available dermoscopes have built-in magnets, electromagnetic interference (EMI) may occur when examining cardiac implantable electronic devices (CIED) patients. The aim of the study was to create maps of electromagnetic fields defining a safe distance in terms of EMI. The study was performed in laboratory conditions using measuring...
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Fe3O4/graphene oxide/Fe4[Fe(CN)6]3 nanocomposite for high performance electromagnetic interference shielding
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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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Minimizing the Impact of Electromagnetic Interference Affecting the Control System of Personal Rapid Transit in the Context of the Competitiveness of the Supply Chain
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Stanisław Galla dr inż.
PeopleStanisław Galla was born in 1970 in Gdańsk. He graduated from the Secondary Technical School of Mechanical and Electrical Engineering in Gdansk (1990). He studied at the Faculty of Electrical Engineering at Gdansk University of Technology (graduated in 1996). His PhD thesis entitled "Methodology for increasing the accuracy of low frequency measurements of periodic disturbance indicators in low voltage networks" was defended in...
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Rafał Lech dr hab. inż.
PeopleIEEE Senior Member #92122578 Rafal Lech was born in Elblag, Poland, in 1977. He received the M.Sc.E.E. and Ph.D. degrees (with honors) from the Gdansk University of Technology, Gdansk, Poland, in 2001 and 2007, respectively. He is currently with the Faculty of Electronics, Department of Microwave and Antenna Engineering, Telecommunications and Informatics, Gdansk University of Technology. His main research interests are electromagnetic-wave...
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Eco-Friendly Electromagnetic Interference Shielding Materials from Flexible Reduced Graphene Oxide Filled Polycaprolactone/Polyaniline Nanocomposites
PublicationHybrid nanocomposites have the unique ability of enhancing material properties due to the existing synergistic effect of the fillers. In this study, the authors report such an eco-friendly hybrid nanocomposite comprising of polyaniline and reduced graphene oxide in polycaprolactone. The conducting polyaniline improved the processability of polycaprolactone, and the final composites were prepared by incorporating graphene oxide...
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Mechanisms positioned in a neighbourhood of their singular positions - velocity amplification in the electromagnetic damping. Part 1 - Background of the mechanical structure modeling
PublicationW pracy przedstawiono metodę modelowania dynamiki drgającego hybrydowego układu mechanicznego złożonego z odkształcalnego podukładu ciągłego oraz z połączonego z nim mechanizmu. U układzie pojawiają się drgania części odkształcalnej. By je wytłumić, ich energia zamieniana jest w energię elektryczną (za pomocą prądnicy prądu stałego) i rozpraszana na oporności obecnej w układzie elektrycznym. Aby przyśpieszyć tłumienie, wprowadzony...
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Induction of secondary metabolite production in transformated callus of Ammi majus L. grown after electromagnetic treatment of culture medium
PublicationW pracy przedstawiono wyniki badań, których celem było zbadanie wpływu elicytacji przy użyciu ADR-4, na produkcję metabolitów wtórnych. Elicytacja ADR-4 zwiększyła 2-krotnie zawartość bergaptenu. Porównano również efektywność 3 technik ekstrakcyjnych stosowanych do izolacji feuranokumaryn, kumaryn i ich glikozydów z kalusa A.majus. Ekstrakcja przy użyciu techniki ASE okazała się najbardziej efektywna.
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Size-defined synthesis of magnetic nanorods by Salvia hispanica essential oil with electromagnetic excitation properties useful in microwave imagining
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Increase of ibuprofen penetration through the skin by forming ion pairs with amino acid alkyl esters and exposure to the electromagnetic field
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Cost‐efficient performance‐driven modelling of multi‐band antennas by variable‐fidelity electromagnetic simulations and customized space mapping
PublicationElectromagnetic (EM) simulations have become an indispensable tool in the design of contemporary antennas. EM‐driven tasks, for example, parametric optimization, entail considerable computational efforts, which may be reduced by employing surrogate models. Yet, data‐driven modelling of antenna characteristics is largely hindered by the curse of dimensionality. This may be addressed using the recently reported domain‐confinement...
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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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Safety Analysis for the Operation Process of Electronic Systems Used Within the Mobile Critical Infrastructure in the Case of Strong Electromagnetic Pulse Impact
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Bandwidth-size design trade-offs for compact spline-parameterised patch couplers by means of electromagnetic-driven multi-objective optimisation
PublicationBroad bandwidth and small size are the key performance figures for contemporary microwave couplers. These requirements are conflicting, i.e. improvement of one generally leads to degradation of the other assuming fixed topology of the circuit at hand. From a designer's perspective, the knowledge about available design trade-offs is indispensable as it permits for tailoring the circuit for particular applications as well as comparing...
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Fundamental properties of solutions to fractional-order Maxwell's equations
PublicationIn this paper, fundamental properties of solutions to fractional-order (FO) Maxwell's equations are analysed. As a starting point, FO Maxwell's equations are introduced in both time and frequency domains. Then, we introduce and prove the fundamental properties of electromagnetic field in FO electromagnetics, i.e. energy conservation, uniqueness of solutions, and reciprocity. Furthermore, the algorithm of the plane wave simulation...
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Electromagnetic wave scattering in structures containing cylindrical object.**2005, 177 s. 119 rys. 8 tab. bibliogr. 239 poz.
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Electromagnetic Control and Dynamics of Generalized Burgers’ Nanoliquid Flow Containing Motile Microorganisms with Cattaneo–Christov Relations: Galerkin Finite Element Mechanism
PublicationIn our research work, we have developed a model describing the characteristics of the bio-convection and moving microorganisms in the flows of a magnetized generalized Burgers’ nanoliquid with Fourier’s and Fick’s laws in a stretchable sheet. Considerations have been made to Cattaneo–Christov mass and heat diffusion theory. According to the Cattaneo–Christov relation, the Buongiorno phenomenon for the motion of a nanoliquid in...
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GPU-Accelerated LOBPCG Method with Inexact Null-Space Filtering for Solving Generalized Eigenvalue Problems in Computational Electromagnetics Analysis with Higher-Order FEM
PublicationThis paper presents a GPU-accelerated implementation of the Locally Optimal Block Preconditioned Conjugate Gradient (LOBPCG) method with an inexact nullspace filtering approach to find eigenvalues in electromagnetics analysis with higherorder FEM. The performance of the proposed approach is verified using the Kepler (Tesla K40c) graphics accelerator, and is compared to the performance of the implementation based on functions from...
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Progress in Electromagnetics Research Letters
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Importance of Specific Heat Characterization when Reporting New Superconductors: An Example of Superconductivity in LiGa2Rh
PublicationWe show that the full-Heusler compound LiGa2Rh is a superconductor with Tc = 2.4 K. The new superconductor was found as a result of an intuition-based extension of a database search for superconductors that looked for the presence of peaks in the electronic band structure near the Fermi energy. The measurement of the entropy loss during the transition from the nonsuperconducting to the superconducting state, a straightforward measurement...
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Superconductivity and Superconducting Materials
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Superconductivity and superconducting compounds
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Ti4Ir2O : A time reversal invariant fully gapped unconventional superconductor
PublicationHere we report muon spin rotation (μSR) experiments on the temperature and field dependence of the effective magnetic penetration depth λ(T ) in the η-carbide-type suboxide Ti4Ir2O, a superconductor with a considerably high upper critical field. The temperature dependence of λ(T ), obtained from transverse-field (TF)-μSR measurements, is in perfect agreement with an isotropic fully gaped superconducting state. Furthermore, our...
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Superconductivity in the Cu(Ir1-xPtx)2Se4 spinel
PublicationWe report the observation of superconductivity in the CuIr2Se4 spinel induced by partial substitution of Pt for Ir. The optimal doping level for superconductivity in Cu(Ir1-xPtx )2Se4 is x = 0.2, where Tc is 1.76 K. A superconducting Tc vs composition dome is established between the metallic, normal conductor CuIr2Se4 and semiconducting CuIrPtSe4. Electronic structure calculations show that the optimal Tc occurs near the electron count...