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Wyniki wyszukiwania dla: FIELD-CIRCUIT COOPERATIVE ANALYSIS, FULL-WAVE EQUIVALENT CIRCUIT, MICROSTRIP STRUCTURES, PARTIAL ELEMENT EQUIVALENT CIRCUIT (PEEC).
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Longitudinal wave propagation. Part II—Analysis of crack influence
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Wave propagation in delaminated beam
PublikacjaW pracy przedstawiono model oraz wyniki analizy propagacji fali sprezystejw belce z delaminacją.
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An Efficient Framework For Fast Computer Aided Design of Microwave Circuits Based on the Higher-Order 3D Finite-Element Method
PublikacjaIn this paper, an efficient computational framework for the full-wave design by optimization of complex microwave passive devices, such as antennas, filters, and multiplexers, is described. The framework consists of a computational engine, a 3D object modeler, and a graphical user interface. The computational engine, which is based on a finite element method with curvilinear higher-order tetrahedral elements, is coupled with built-in...
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Highly Integrable Planar-structured Printed Circularly Polarized Antenna for Emerging Wideband Internet of Things Applications in the Millimeter-Wave Band
PublikacjaThis paper proposes a numerically and experimentally validated printed wideband antenna with a planar geometry for Internet of Things (IoT) applications. This design tackles the challenges associated with deploying IoT sensors in remote areas or across extensive geographical regions. The proposed design exploits a coplanar-waveguide-fed modified microstrip line monopole for excitation of circularly polarized waves radiating in...
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The dynamic analysis of a cracked Timoshenko beam by the spectral element method
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adaptive finite-element multigrid method in 3d magnetostatic analysis.
PublikacjaPrzedstawiono procedurę analizy magnetostatycznej obwodów mikrofalowych zawierających przewodniki o dowolnym kształcie. Zakłada się pobudzenie pola magnetostatycznego zadane w postaci wartości całkowitego prądu płynącego w przewodniku sygnałowym. Warunki brzegowe w strukturze od dowolnym kształcie, bez płaszczyzn symetrii wprowadza się za pomocą powierzchni rozdzielających. Takie sformułowanie problemu prowadzi jednak do szeregu...
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Experiences with viscoplastic constitutive equations in finite element shell analysis
PublikacjaW pracy przedstawiono problemy zastosowania lekoplastycznych równań konstytutywnych w anlizie powłok metodą elementów skończonych. Pokazano historie rozwoju tego rodzaju modeli. Rozważono podstawowe założenia jakie muszą być zrobione.Omówiono doświadczenia konieczne do identyfikacji parametrów materiałowych modeli. Przedstawiono problemy jakie mogą wynikną w analizie numerycznej (problemy dokładności i stabilności algorytmów) Pracę...
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Multisource model of ship electric field
PublikacjaA steel-hulled ship in sea water produces an electric field around itself. The source of this field are electrochemical processes and ship's cathodic protection. The analysis of the electric field around the ship is important by the reason of the ship's identification and counter-mine protection. The paper presents a simplified model of the ship's multisource electric field, which allows to calculate the electric field distribution...
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Dynamics of Field Line Mappings in Magnetic Flux Tubes
PublikacjaWe study the topological constraints on the dynamics of magnetic field lines in flux tubes. Our approach is based on the application of the topological invariant: fixed point index. We consider periodic flux tubes and find various restrictions on the field lines that come from the sequence of fixed point indices of iterations. We also analyze the case of a tube with a cylindrical obstacle, deducing some special dynamical properties...
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Finite Element Method Applied in Electromagnetic NDTE: - A Review
PublikacjaThe paper contains an original comprehensive review of finite element analysis (FEA) applied by researchers to calibrate and improve existing and developing electromagnetic non-destructive testing and evaluation techniques, including but not limited to magnetic flux leakage (MFL), eddy current testing, electromagnetic-acoustic transducers (EMATs). Premium is put on the detection and modelling of magnetic field, as the vast majority...
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Rapid Variable-Resolution Parameter Tuning of Antenna Structures Using Frequency-Based Regularization and Sparse Sensitivity Updates
PublikacjaGeometry parameter tuning is an inherent part of antenna design process. While most often performed in a local sense, it still entails considerable computational expenses when carried out at the level of full-wave electromagnetic (EM) simulation models. Moreover, the optimization outcome may be impaired if good initial design is not available. This paper proposes a novel approach to fast and improved-reliability gradient-based...
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Cooperative editing approach for building Wordnet database
PublikacjaArtykuł przedstawia podejście do kooperacyjnej pracy nad baza danych systemu Wordnet. Opisana została architektura systemu oraz wizualizacja sieci powiązań konceptualnych z użyciem komponentu touchgraph.
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On the non-linear dynamics of torus-shaped and cylindrical shell structures
PublikacjaIn this study, the non-linear dynamic analysis of torus-shaped and cylindrical shell-like structures has been studied. The applied material is assumed as the functionally graded material (FGM). The structures are considered to be used for important machines such as wind turbines. The effects of some environmental factors on the analysis like temperature and humidity have been considered. The strain field has been calculated in...
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Mixed 4-node shell element with assumed strain and stress in 6-parameter theory
PublikacjaWe propose a mixed hybrid 4-node shell elements based on Hu-Washizu principle. Apart from displacements both strains and stress fields are treated as independent fields. The element is derived in the framework of a general nonlinear 6-field shell theory with drilling rotation which is dedicated to the analysis of multifold irregular shells with intersections. The novelty of the presented results stems from the fact that the measures...
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Mixed 4-node shell element with assumed strain and stress in 6-parameter theory
PublikacjaWe propose a mixed hybrid 4-node shell elements based on Hu-Washizu principle. Apart from displacements both strains and stress fields are treated as independent fields. The element is derived in the framework of a general nonlinear 6-field shell theory with drilling rotation which is dedicated to the analysis of multifold irregular shells with intersections. The novelty of the presented results stems from the fact that the measures...
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Validation Process for Computational Model of Full-Scale Segment for Design of Composite Footbridge
PublikacjaExperimental tests and numerical simulations of a full-scale segment of a foot and cycle bridge made of polymer composites are presented in the paper. The analysed structure is made of sandwich panels, which consist of glass fibre reinforced polymer (GFRP) multi-layered laminate faces and a PET foam (obtained from recycling) core. The dimensions of the segment cross-section are the same as for the target footbridge; however, span...
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Elastic wave propapagation in diagnostics of self-drilling system of grouted anchors
PublikacjaThe paper presents an experimental investigation of elastic wave propagation in a self-drilling hollow bar system, which is commonly used in geotechnical industry as the element of grouted ground anchors and soil nails. The single self-drilling hollow bar and self-drilling system of two bars connected by a coupler were considered. Longitudinal waves were excited at one end of the bar and registered at both ends, by means of PZT...
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Robust Parameter Tuning of Antenna Structures by Means of Design Specification Adaptation
PublikacjaParameter tuning through numerical optimization has become instrumental in the design of high-performance antenna systems. Yet, practical optimization faces several major challenges, including high cost of massive evaluations of antenna characteristics, normally involving full-wave electromagnetic (EM) analysis, large numbers of adjustable variables, the shortage of reasonable initial solutions in the case of topologically complex...
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Partial dominated schedules and minimizing the total completion time of deteriorating jobs
PublikacjaA problem of scheduling deteriorating jobs on a single processor is considered. The processing time of a job is given by a function pi=ai+bisi, where si is the starting time of the job, ai>=0, bi>=0, for i=1,...,n. Jobs are non-preemptive and independent and there are neither ready times nor deadlines. The goal is to minimize the total weighted completion time. We show how to employ the concept of non-dominated schedules to construct...
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Nonlinear finite element modeling of vibration control of plane rod-type structural members with integrated piezoelectric patches
PublikacjaThis paper addresses modeling and finite element analysis of the transient large-amplitude vibration response of thin rod-type structures (e.g., plane curved beams, arches, ring shells) and its control by integrated piezoelectric layers. A geometrically nonlinear finite beam element for the analysis of piezolaminated structures is developed that is based on the Bernoulli hypothesis and the assumptions of small strains and finite...
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Seismic pounding behavior of multi-story buildings in series considering the effect of infill panels
PublikacjaThe aim of the present paper is to study the influence of the infill panels on the seismic pounding response of adjacent structures in series. The contribution of the masonry infill has been simulated using equivalent diagonal compression struts. Steel frames have been assumed to have elastic-plastic behavior with 1% linear strain hardening. The dynamic contact analysis has been utilized where contact surface model (target and...
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Design of Microstrip UWB Balun Using Quasi-TEM Approach Aided by the Artificial Neural Network
PublikacjaThe design procedure for UWB balun realized in the microstrip technology is proposed in the paper. The procedure applies Artificial Neural Network which corrects the dimensions of the approximate design found by appropriate scaling of the dimensions of the prototype. The scale coefficients for longitudinal and transverse dimensions of microstrip lines are determined from electromagnetic modeling based on transmission line equations....
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Comparative Analysis of Salient and Non-Salient Pole Brushless Synchronous Generator for Application in Autonomous Electric Power System
PublikacjaThis paper presents a comparative study of two types of brushless synchronous generator for application in autonomous electric power systems (e.g. airplane power grid). Commercially used salient pole and a prototype non-salient pole high speed multi-pole brushless synchronous generator (BSG) have been presented. Comparative analysis of both types of the generator has been performed. Chosen simulation (using FEM and circuit models)...
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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...
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Nonlinear Excitation of the Non-Wave Perturbations by the Magnetoacoustic Waves in the Non-Isentropic Plasma
PublikacjaNonlinear excitation of slow modes by the planar magnetosonic perturbations in a plasma is discussed. Plasma is an open system due to radiation and external heating. This may stipulate enhancement of wave perturbations and hence the acoustical activity of plasma. Plasma is assumed to be a homogeneous ideal gas with infinite electrical conductivity. The straight magnetic field is orthogonal to the velocity of fluid’s...
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Accurate Modeling of Antenna Structures by Means of Domain Confinement and Pyramidal Deep Neural Networks
PublikacjaThe importance of surrogate modeling techniques has been gradually increasing in the design of antenna structures over the recent years. Perhaps the most important reason is a high cost of full-wave electromagnetic (EM) analysis of antenna systems. Although imperative in ensuring evaluation reliability, it entails considerable computational expenses. These are especially pronounced when carrying out EM-driven design tasks such...
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GPU-Accelerated 3D Mesh Deformation for Optimization Based on the Finite Element Method
PublikacjaThis paper discusses a strategy for speeding up the mesh deformation process in the design-byoptimization of high-frequency components involving electromagnetic field simulations using the 3D finite element method (FEM). The mesh deformation is assumed to be described by a linear elasticity model of a rigid body; therefore, each time the shape of the device is changed, an auxiliary elasticity finite-element problem must be solved....
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Reference-free determination of debonding length in reinforced concrete beams using guided wave propagation
PublikacjaThis paper presents theoretical and experimental investigations of guided wave propagation in reinforced concrete beams, with pre-existing debonding between steel rebars and concrete blocks, for the purpose of damage detection. The primary aim of these investigations was a detailed analysis of the possible applications of wave propagation in single and multiple debonding detection in reinforced concrete structures and reference-free...
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Simulation of Wave Propagation in Media Described by Fractional-Order Models
PublikacjaIn this paper, algorithms for simulation of the wave propagation in electromagnetic media described by fractional-order (FO) models (FOMs) are presented. Initially, fractional calculus and FO Maxwell's equations are introduced. The problem of the wave propagation is formulated for media described by FOMs. Then, algorithms for simulation of the non-monochromatic wave propagation are presented which employ computations in the time...
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Experimental tests and numerical simulations of full scale composite sandwich segment of a foot- and cycle- bridge
PublikacjaIn the paper experimental tests and numerical simulations of a full cross-section segment of ultimately designed foot-and cycle-bridge are presented. The experimental tests were conducted on element with length reduced to 3 m and unchanged (target) cross-section dimensions. The external skin of structure is GFRP laminate while internal core is PET foam. Several quasi-static tests were performed using hydraulic cylinder to generate...
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Wave Frequency Effects on Damage Imaging in Adhesive Joints Using Lamb Waves and RMS
PublikacjaStructural adhesive joints have numerous applications in many fields of industry. The gradual deterioration of adhesive material over time causes a possibility of unexpected failure and the need for non-destructive testing of existing joints. The Lamb wave propagation method is one of the most promising techniques for the damage identification of such connections. The aim of this study was experimental and numerical research on...
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Spectral Finite Element Method in Condition Monitoring and Damage Detection
PublikacjaIt is well known that the dynamic behaviour of engineering structures may carry very important and crucial information that can be further used for the assessment of their condition as well as detection of any damage induced. The current interest in monitoring techniques based on the propagation of guided elastic waves requires that numerical techniques used for modelling the phenomena associated must shift into the realm of high...
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Debonding Size Estimation in Reinforced Concrete Beams Using Guided Wave-Based Method
PublikacjaThe following paper presents the results of the theoretical and experimental analysis of the influence of debonding size on guided wave propagation in reinforced concrete beams. The main aim of the paper is a development of a novel, baseline-free method for determining the total area of debonding between steel rebar embedded in a concrete cover on the basis of the average wave velocity or the time of flight. The correctness of...
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TRANSFER OF ELECTRIC ENERGY [2023/24]
Kursy OnlineCourse content: Basic information on the structure of the power system, the major devices (components) for generation, transmission and distribution of electricity. Active and reactive power generation and their sources. Power supply networks. Tasks, structure, parameters. AC and DC transmission of electricity. Equivalent diagrams of the components of the power system. Steady state load flow calculation: currents, voltage,...
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TRANSFER OF ELECTRIC ENERGY [2022/23]
Kursy OnlineCourse content: Basic information on the structure of the power system, the major devices (components) for generation, transmission and distribution of electricity. Active and reactive power generation and their sources. Power supply networks. Tasks, structure, parameters. AC and DC transmission of electricity. Equivalent diagrams of the components of the power system. Steady state load flow calculation: currents, voltage,...
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Rafał Lech dr hab. inż.
OsobyIEEE Senior Member #92122578 Rafał Lech urodził się w Elblągu w 1977 roku. W roku 2001 otrzymał tytuł magistra inżyniera, w roku 2007 stopień doktora nauk technicznych (z wyróżnieniem) a w roku 2018 stopień doktora habilitowanego nauk technicznych w dyscyplinie elektronika w Politechnice Gdańskiej. Obecnie pracuje w Katedrze Inżynierii Mikrofalowej i Antenowej na Wydziale Elektroniki, Telekomunikacji i Informatyki w Politechnike...
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Research of leakage magnetic field in deenergized transformer
PublikacjaThe article deals with the issue of the numerical analysis of the magnetic field occurring around the transformer after it has been powered down. The main goal of this analysis was to examine if it is possible to identify the residual fluxes in the transformer legs based on this fields’ measurements. It was also intended to determine the type and the location of magnetic sensors. Numerical analysis of the magnetic field was performed....
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Application of superelements in static analysis of thin‐walled structures
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Wavelet analysis in detection and localization of damage in engineering structures
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Application of superelements in static analysis of thin-walled structures.
PublikacjaW pracy omówiono koncepcję zastosowania superelementów MES w statycznej analizie konstrukcji cienkościennych ze szczególnym uwzględnieniem belek cienkościennych wzmocnionych stężeniami oraz węzłów ram zbudowanych z elementów cienkościennych. W zamieszczonych przykladach numerycznych rozwiazania uzyskane z pomoca superelementów porównano z wynikami otrzymanymi przy gestej dyskretyzacji MES całej konstrukcji elementami powłokowymi.
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A review of structures, properties and analysis of volatile amines in the environment
PublikacjaOmówiono właściwości i źródła wytwarzania lotnych amin alifatycznych. Uwzględniono również ich wpływ na organizmy żywe. Przedstawiono liczne naturalne i antropogeniczne źródła amin. Omówiono problemy analityczne związane z oznaczaniem amin w próbkach środowiskowych, przygotowaniem próbek do analizy chromatograficznej oraz nowe techniki oznaczania lotnych amin alifatycznych.
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Microstrip four-port circulator using a ferrite coupled line section
PublikacjaThis paper describes an alternative configuration of a four-port circulator realized in a microstrip ferrite coupled line technology. The proposed fully planar device employs two three-port circulators consisting of a ferrite coupled line junction and T junction. Both circulators are connected through the same arm, hence, the problem of anti-parallel magnetization met in this type of circulators is avoided without the increase...
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Distortions in structures of the twist bend nematic phase of a bent-core liquid crystal by the electric field
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Prediction of the structures of proteins with the UNRES force field, including dynamic formation and breaking of disulfide bonds
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Investigations of vortex-structures in granular bodies based on DEM and Helmholtz-Hodge flow field decomposition
PublikacjaArtykuł omawia wyniki numeryczne dotyczące struktur wirowych w materiałach granulowanych. Obliczenia wykonano dla stanu pasywnego przemieszczającej się sztywnej ścianki. W symulacjach wykorzystano metodę elementów dyskretnych i dekompozycję Helmholtza/Hodge’a pola prędkości. Struktury wirowe okazały się znakomitym prekursorem lokalizacji odkształceń stycznych w materiałach granulowanych.
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Inverse Analysis as a Key Element of Safety Assessment under the Snow Load For The Large Suspension Roofs Structure
PublikacjaThe paper presents a concept and realization of monitoring system for the Silesian Stadium in Chorzow. The idea of the system lies in fusion of structure monitoring with a calibrated numerical FEM model [1]. The inverse problem is solved. On the base of measured selected displacements, the numerical FEM model of the structure combined with iterative method, develops the current snow load distribution. Knowing the load, we can calculate...
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MEASUREMENT AND ANALYSIS OF ELECTRIC FIELD INTENSITY NEAR SELECTED TRANSMITTERS OF MOBILE TELEPHONY BASE STATIONS
PublikacjaWireless connectivity has become increasingly common in recent times. Day by day, there are more radiocommunication devices and new ideas for them. In the near future, when the fifth generation networks will be implemented, whose main feature will be continuous wireless communication, we must approach the issue of electric field measurements more and more carefully.
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Evaluation of the resistance of steel–concrete adhesive connection in reinforced concrete beams using guided wave propagation
PublikacjaThe development of the nondestructive diagnostic methods is of significant importance in the last decades. A special attention is paid to diagnostics of reinforced concrete structures, which are very popular in the civil engineering field. A possible use of the guided waves in the estimation of the resistance of steel–concrete adhesive connection is studied in the following paper. The relationships relating adhesive connection...
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Conley-Morse graphs for a two-dimensional discrete neuron model (full range)
Dane BadawczeThis dataset contains selected results of rigorous numerical computations conducted in the framework of the research described in the paper “Topological-numerical analysis of a two-dimensional discrete neuron model” by Paweł Pilarczyk, Justyna Signerska-Rynkowska and Grzegorz Graff. A preprint of this paper is available at https://doi.org/10.48550/arXiv.2209.03443.
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Novel 1,2,3-Triazole Derivatives as Mimics of Steroidal System—Synthesis, Crystal Structures Determination, Hirshfeld Surfaces Analysis and Molecular Docking
PublikacjaHerein, we present the synthesis and crystal structures determination of five 4-(1-phenyl-1H-1,2,3-triazol-4-yl)phenol derivatives containing halogen atoms, 6a–e, which may be used as an excellent mimic of steroids in the drug development process. Good quality crystals obtained for all of the synthesized compounds allowed the analysis of their molecular structures. Subsequently, the determined crystal structures were used to calculate...