Search results for: ULTRASONIC CODA WAVES
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Validation study on a new semi-empirical method for the prediction of added resistance in waves of arbitrary heading in analyzing ship speed trial results
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Ekspertyza konstrukcji i stanu technicznego napędu rollera rejowego, napędu rollera sztagowego oraz wózka fałowego na sztag s/y "Running on Waves"
PublicationCelem ekspertyzy było ustalenie przyczyn nieprawidłowej pracy urządzeń rejowych i wciągarek. Omówiono błędy projektowe i wykonawcze oraz wskazano przyczyny awarii. Sformułowano wnioski dotyczące kierunków modernizacji konstrukcji.
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Janusz Smulko prof. dr hab. inż.
PeopleHe was born on April 25, 1964 in Kolno. He graduated in 1989 with honors from the Faculty of Electronics at Gdańsk University of Technology, specialising in measuring instruments. In 1989 he took second place in the Red Rose competition for the best student in the Pomerania Region. Since the beginning of his career ha has been associated with Gdańsk University of Technology: research assistant (1989-1996), Assistant Professor (1996-2012),...
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Clinical and Epidemiological Characteristics of 1283 Pediatric Patients with Coronavirus Disease 2019 during the First and Second Waves of the Pandemic—Results of the Pediatric Part of a Multicenter Polish Register SARSTer
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Characterization of corrosion in reinforced concrete beams using destructive and non-destructive tests
PublicationThe paper presents both non-destructive and destructive experimental tests on steel-reinforced concrete beams subjected to electrochemical corrosion. To examine the condition and behavior of the specimens, destructive tests were carried out, i.e., a three-point bending together with a modulated ultrasonic wave test. In addition, a series of non-destructive experiments were conducted, such as the potential measurement method, low-frequency...
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Innowacyjny moduł ultradźwiękowy systemu monitoringu technicznego mostu podwieszonego w Rzeszowie
PublicationW artykule przedstawiono system monitoringu technicznego konstrukcji mostu podwieszonego nad rzeką Wisłok. System będzie wyposażony w dodatkowy moduł ultradźwiękowy umożliwiający śledzenie degradacji mechanicznej betonu w pylonie mostu. Wczesne wykrywanie stref mikropęknięć, przed pojawieniem się widocznych rys, umożliwia monitorowanie amplitud propagującej fali ultradźwiękowej oraz analizę sygnałów w dziedzinie częstotliwości.
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Compressive strength and density of cement pastes containing iron oxide (Fe3O4) nanoparticles (nanomagnetite)
Open Research Data*.ODS - open-data source spreadsheet - Dataset presenting:
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Jarosław Przewłócki prof. dr hab. inż.
PeopleJarosław Przewłócki jest profesorem na Wydziale Architektury Politechniki Gdańskiej, zastępca kierownika Katedry Technicznych Podstaw Projektowania Architektonicznego. Podstawowym kierunkiem jego działalności naukowej są badania zjawisk losowych i zastosowanie metod probabilistycznych oraz teorii niezawodności w budownictwie, a w szczególności w geotechnice. Autor i współautor około stu publikacji naukowych, w tym szeregu książek...
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APPLICATION OF THE HIGH FREQUENCY LINEARIZATION OF THE EAR IN PATIENTS WITH TINNITUS . Metoda linearyzacji narządu słuchu u osób cierpiących z szumami usznymi
PublicationThis paper summarises the problem of tinnitus, hypotheses on its causes and the treatment methods. Moreover, a hypothesis on tinnitus origins is explained, based on the mechanisms of the analog-to-digital conversion and quantization. In addition, this paper describes methods of determining the acoustic intensity and spectra of low- level ultrasonic signals, as well as impedance characteristics of an ultrasound transducer. Furthermore,...
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Abdalraheem Ijjeh Ph.D. Eng.
PeopleThe primary research areas of interest are artificial intelligence (AI), machine learning, deep learning, and computer vision, as well as modeling physical phenomena (i.e., guided waves in composite laminates). The research interests described above are utilized for SHM and NDE applications, namely damage detection and localization in composite materials.
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Ship model resistance - KCS
Open Research DataShip model instantaneous resistance, velocity, pitch and heave measured data for a KCS built and tested in the towing tank of the Faculty of Mechanical Engineering and Ship Technology of Gdansk University of Technology under regular head waves.
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Katania, 2023, Road SS114 – csv data from sensors on bicycle
Open Research DataData collected with bicycle-mounted sensors on 06.07.2023 while cycling on the cycle path along the SS114 road in Catania. The data includes parameters such as: gps coordinates- txt files, brain waves and heart rate- csv file.
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YSZ Thin film deposited on porous substrate by spray pyrolysis
PublicationIn this work the results of deposition of YSZ layer on a porous substrate using an ultrasonic Spray Pyrolysis are presented.
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Developments in ultrasound-assisted microextraction techniques for isolation and preconcentration of organic analytes from aqueous samples
PublicationThe great potential of ultrasonic assistance in sample preparation, especially extraction, is being recognized. In this review, we discuss the applications of ultrasonic radiation in assisting microextraction. Topics covered include ultrasound-assisted emulsification microextraction, ultrasound-assisted-emulsification-dispersive liquid-liquid microextraction, and ultrasound-assisted hollow-fiber liquid-phase microextraction with...
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Polymer based thick films - material quality and interface resistance evaluation
PublicationThe properties of polymer based thick film layers mede using different resistive pastes and dipping silvers have been studied. The composite of carbon and graphite (C/Gr) conducting particles suspended in different polymer vehicles were used for preparation resistive layers. Interface resistance Rc created between dipping silver (DiAg) contact layer and resistive layer was determined from the surface potential distribution measurements...
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Intensification of catechin extraction from the bark of Syzygium cumini using ultrasonication: Optimization, characterization, degradation analysis and kinetic studies
PublicationCatechin is a prominent polyphenolic component that possesses various medicinal properties. Present work communicates the intensification and optimization of catechin extraction from the bark of Syzygium cumini tree using stirred reactor, soxhlet, ultrasonic bath, and ultrasonic horn technique. The optimization of several parameters such as type of solvent, solid to solvent ratio (1:100 w/v), speed of agitation (300 RPM), extraction...
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Modelling of in-plane wave propagation in a plate using spectral element method and Kane-Mindlin theory with application to damage detection
PublicationThis paper presents results of experimental and numerical analyses of in-plane waves propagatingin a 5 mm-thick steel plate in the frequency range of 120-300 kHz. For such a thickness/frequency ratio,extensional waves reveal dispersive character. To model in-plane wave propagation taking into account thethickness-stretch effect, a novel 2D spectral element, based on the Kane-Mindlin theory, was formulated. Anapplication of in-plane...
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Diagnostics of bolted lap joint using guided wave propagation
PublicationThe paper presents numerical and experimental analyses of elastic waves propagation in a bolted lap joint. In experimental investigations condition assessment of the joint was performed with the use of symmetric waves excited by a piezoactuator. Numerical calculations were conducted in commercial finite element method software Abaqus. The influence of number of bolts and the value of the initial stress on recorded signals was examined....
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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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Acoustical images of the Gulf of Gdansk
PublicationAcoustic images of seabed are of interest to specialists in the field of marine engineering, marine navigation, marine archeology, hydrogeology, etc. New technolo gies based on use of elastic waves, predominantly acoustic waves that allow detecting complexity of geometric forms of seabed, ensure progress in studying the bathymetric structure of seafloor. Use of parametric sources of waves generated...
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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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Measurements of guided wave propagation in CFRP/steel adhesive joints obtained by scanning laser vibrometry
Open Research DataThe DataSet contains guided wave signals measured in adhesive joints of steel plates (steel of type S355 with a thickness of 11.9 mm ) and carbon fibre reinforced polymer (CarboDur S1012 with a thickness of 1.24 mm). The samples were as follows: #0 – intact; #1 – 10% disbond; #2 – 20% disbond; #3 – 50% disbond; #4 – 80% disbond; #5 – 100% disbond.
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Analysis of guided wave propagation in adhesive joints of steel rods
PublicationThe aim of the study is the elastic wave propagation in adhesive joints of metal rods that are one of the simplest kind of glue connections. They are consisted of two metal members and an adhesive layer joining two parts together. The analysis is directed to technical diagnostics of such type of connections. Longitudinal and transversal guided waves were excited in prepared joints. Signals of propagating waves were registered in...
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SEM micrographs of the topography of Cu-Sn-TiO2 nanocomposite coatings
Open Research DataThe dataset contains the scanning electron microscopy (SEM) micrographs of nanocomposite Cu-Sn-TiO2 coatings electrodeposited from oxalic acid bath containing Cu and Sn salts as well as TiO2 nanoparticles under various treatments: mechanical stirring, ultrasonic or none. The details of the electrodeposition process are presented in the readme file attached...
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Prediction of the Mechanical Properties of P91 Steel by Means of Magneto-acoustic Emission and Acoustic Birefringence
PublicationThe paper describes an application of nondestructive volumetric magnetic and ultrasonic techniques for evaluation of the selected mechanical parameter variations of P91 steel having direct influence on its suitability for further use in critical components used in power plants. Two different types of deformation processes were carried out. First, a series of the P91 steel specimens was subjected to creep and second, one to plastic...
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Numerical analysis of elastic wave propagation in unbounded structures
PublicationThe main objective of this paper is to show the effectiveness and usefulness of the concept of an absorbing layer with increasing damping (ALID) in numerical investigations of elastic wave propagation in unbounded engineering structures. This has been achieved by the authors by a careful investigation of three different types of structures characterised by gradually increasing geometrical and mathematical description complexities....
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Theoretical Model of Acoustic Wave Propagation in Shallow Water
PublicationThe work is devoted to the propagation of low frequency waves in a shallow sea. As a source of acoustic waves, underwater disturbances generated by ships were adopted. A specific feature of the propagation of acoustic waves in shallow water is the proximity of boundaries of the limiting media characterised by different impedance properties, which affects the acoustic field coming from a source situated in the water layer “ deformed”...
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Ocean mixed layer dynamics: high-resolution simulations of wind, wave and convective effects
Open Research DataThis dataset contains results of high-resolution numerical simulations of the ocean mixed layer (OML) forced by wind, waves and cooling from the atmosphere, i.e., under strongly turbulent, convective conditions. The goal is to provide detailed, three-dimensional information about OML circulation, turbulent kinetic energy, and temperature and salinity...
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Elastic wave propagation for condition assessment of steel bar embedded in mortar
PublicationThis study deals with experimental and numerical investigations of elastic wave propagation in steel bars partially embedded in mortar. The bars with different bonding lengths were tested. Two types of damage were considered: damage of the steel bar and damage of the mortar. Longitudinal waves were excited by a piezoelectric actuator and a vibrometer was used to non-contact measurements of velocity signals. Numerical calculations...
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The SEM micrographs of the synergistic action between cavitation erosion and pitting corrosion on stainless steel 304
Open Research DataThe dataset contains Scanning Electron Micrographs of stainless steel AISI304 samples made after cavitation erosion-corrosion exposure using a vibratory transducer (in accordance with ASTM G32). The micrographs compare the topography of samples subjected to either cavitation erosion (in deionized water), pitting corrosion (in 8% FeCl3 solution, without...
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Approximate solution for Euler equations of stratified water via numerical solution of coupled KdV system
PublicationWe consider Euler equations with stratified background state that is valid for internal water waves. The solution of the initial-boundary problem for Boussinesq approximation in the waveguide mode is presented in terms of the stream function. The orthogonal eigenfunctions describe a vertical shape of the internal wave modes and satisfy a Sturm-Liouville problem. The horizontal profile is defined by a coupled KdV system which is...
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The SEM micrographs of the cavitation erosion-corrosion process of selected copper alloys degradation
Open Research DataThe dataset contains Scanning Electron Micrographs of CuZn40Mn3Fe brass compared with Superston and Novoston bronze after cavitation erosion-corrosion exposure using a vibratory transducer (in accordance with ASTM G32). The micrographs compare the topography of samples subjected cavitation erosion in 3% NaCl at room temperature, leading to the surface...
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SEM micrographs of cavitation erosion-corrosion of aluminium alloy 2024 with anodic polarization
Open Research DataThe dataset contains Scanning Electron Micrographs of aluminium alloy 2024 samples made after cavitation erosion-corrosion exposure using a vibratory transducer (in accordance with ASTM G32). The experiment duration was 240 min, with cyclic cavitation exposure in on/off cycles 30s:30s. The electrolyte was 0.1 M KNO3 solution. Some samples were anodically...
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Initial Investigation of Wave Interactions During Simultaneous Valve Closures in Hydraulic Piping Systems
PublicationThe effects of interference of pressure waves in simple piping systems were studied. A freeware computer code Allievi developed at the University of Valencia was used to simulate dynamic waveforms in simple and complex networks. The tests were carried out according to three scenarios. No pressure increases significantly exceeding the Joukowsky pressure in simple cases were noticed. When the effects of the simultaneous closing of...
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Investigating Fuel Injection Strategies to Enhance Ship Energy Efficiency in Wave Conditions
PublicationThe prediction of fuel consumption and resulting transportation costs is a crucial stage in ship design, particularly for conditions involving motion in waves. This study investigates the real-time fuel consumption of a container ship when sailing in waves. The overall ship performance is evaluated using a novel non-linear coupled hull-engine-propeller interaction model. A series of towing tank experiments for hull resistance in...
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Wave transmission across surface interfaces in lattice structures
PublicationWithin the lattice dynamics formulation, we present an exact solution for anti-plane surface waves in a square lattice strip with a surface row of material particles of two types separated by a linear interface. The considered problem is a discrete analog of an elastic half-space with surface stresses modelled through the simplified Gurtin–Murdoch model, where we have an interfacial line separating areas with different surface...
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Nonlinear Interaction of Magnetoacoustic Modes in a Quasi-Isentropic Plasma Flow
PublicationThe nonlinear interaction of magnetoacoustic waves in a plasma is analytically studied. A plasma is an open system. It is affected by the straight constant equilibrium magnetic flux density forming constant angle with the wave vector which varies from 0 till . The nonlinear instantaneous equation which describes excitation of secondary wave modes in the field of intense magnetoacoustic perturbations is derived by use of projecting....
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Nanotechnologies in Development of Structural Materials and Biomaterials
PublicationThe nanometric materials and technologies resulted in nanostructures are reviewed. The examples of nanomaterials are shown. The typical nanotechnologies, including plastic deformation, mechanical attrition, controlled detonation, hot plasma jet synthesis, laser vaporisation, CVD and PVD, mechanical milling, annealing, ultrasonic irradiation, nanolithography, electrocrystallisation, electrospinning, sol-gel method, cryogenic laser-enhanced...
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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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Rapid multi-objective design of integrated on-chip inductors by means of Pareto front exploration and design extrapolation
PublicationIdentification of the best trade-offs between conflicting design objectives allows for making educated design decisions as well as assessing suitability of a given component or circuit for a specific application. In case of inductors, the typical objectives include maximization of the quality factor and minimization of the layout area, as well as maintaining a required inductance at a given operating frequency. This work demonstrates...
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Recurrence scheme for FDTD-compatible discrete Green's function derived based on properties of Gauss hypergeometric function
PublicationIn this paper, the formulation of one-dimensional FDTD (Finite-difference time-domain)-compatible discrete Green's function (DGF) is derived based on the Gauss hypergeometric function (GHF). The properties of GHF make it possible to derive the recurrence scheme only in the time domain for the DGF generation. Furthermore, this recurrence scheme is valid for any stable time-step size and can be implemented using standard numerical...
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Design and optimization of a novel miniaturized low-profile circularly polarized wide-slot antenna
PublicationThis paper presents a novel structure of a compact circularly polarized (CP) antenna. CP is obtained using a parasitic quasi-rectangular strip placed coplanar to the feedline. A ground plane perturbation combined with the asymmetric geometry of the coplanar waveguide ground planes is utilized to excite additional CP modes. All antenna dimensions are rigorously optimized to achieve the best possible performance in terms of the impedance...
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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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Design of UWB coplanar antenna with reduced ground plane
PublicationW artykule przedstawiono projekt kompaktowej anteny szerokopasmowej złożonej z dwóch kołowych pasków koplanarnych ograniczających szczelinę o podobnym kształcie. Antena zasilona była z 50 Ω linii trójpaskowej. Przeprowadzono badania wpływu zewnętrznego paska na pasmo anteny. Zaprojektowana antena została zbadana eksperymentalnie pokazując bardzo dobre parametry: w paśmie 1.7-15.5GHz uzyskano |S11| < −10dB. Antena charakteryzowała...
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Investigations of nonreciprocal devices employing cylindrical ferrite coupled line junction
PublicationArtykuł opisuje wykorzystanie cylindrycznej sekcji ferrytowych linii sprzężonych do realizacji układów niewzajemnych. W artykule opisano proces projektowy izolatora ferrytowego wykorzystującego badaną sekcję oraz planarne układy zasilające. Uzyskane z symulacji wyniki zostały zweryfikowane eksperymentalnie.
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Resonance microstrip structure with patch of arbitrary convex geometry with the use of field matching technique
PublicationAn analysis of the resonance frequency problem of planar microstrip structure with patch of arbitrary convex geometry is presented. A full-wave analysis is employed utilizing a combination of Galerkin’s moment method and field matching technique. In this approach, a field matching technique is adopted to calculate the patch surface current densities, and next the method of moments is utilized to calculate resonance frequencies...
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Finite element/mode-matching analysis of ferrite/dielectric line junctions of arbitrary cross-section
PublicationThis paper is focused on the analysis of line junctions obtained as a cascade of dielectric and ferrite guides of arbitrary cross-section. The main application of such structures is nonreciprocal devices such as isolators, circulators, or phase shifters. The efficient finite element/mode-matching approach is proposed to the analysis of such structures. In this approach, thefiniteelementmethod is applied todetermine propagation...
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Left-handed propagation characteristics of a dielectric and metal-loaded periodic circular waveguide
PublicationIn this paper, a periodic dielectric/metallic rod is located in a circular waveguide to obtain left-handed operation. Two geometries of the dielectric/metallic rod are proposed and examined. The dispersion characteristics of the investigated waveguides are obtained using a surface impedance model. Moreover, equivalent circuit models are proposed allowing for calculation of the dispersion characteristics and scattering parameters...
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Scattering by an array of conducting, lossy dielectric, ferrite and pseudochiral cylinders.
PublicationOpisano metodę analizy rozpraszania fali elektromagnetycznej w systemach zawierających cylindryczne pręty dielektryczne, metalowe, ferytowe i pseudochiralne i wykorzystanie w/w metody w problemach zamkniętych i znajdowanie macierzy rozpraszania wieloportowych złączy falowodowych oraz w problemach otwartych i badanie charakterystyk rozpraszania zarówno w strefie dalekiej jaki bliskiej.
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Electro-thermal buckling of elastically supported double-layered piezoelectric nanoplates affected by an external electric voltage
PublicationPurpose Thermal buckling of double-layered piezoelectric nanoplates has been analyzed by applying an external electric voltage on the nanoplates. The paper aims to discuss this issue. Design/methodology/approach Double-layered nanoplates are connected to each other by considering linear van der Waals forces. Nanoplates are placed on a polymer matrix. A comprehensive thermal stress function is used for investigating thermal buckling....