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Search results for: FINITE ELEMENT METHOD · ELECTROMAGNETIC NON-DESTRUCTIVE TESTING · MFL · EDDY CURRENT TESTING · EMATS
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Modal analysis of railway current collectors using Autodesk Inventor
PublicationThe paper presents the results of modal analysis of railway current collector type 160EC. In the first place, the analysis was carried out analytically for a simplified two lumped mass pantograph model. Then numerical analysis was conducted in the Autodesk Inventor (AI) on the prepared multibody model using the AI modal analysis algorithm, which is based on the finite element method (FEM). Model elements which are most relevant...
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Ultrasonic Tomography of Brick Columns Based on FEM Calculations
PublicationUltrasonic tomography is one of the most developed method of non-destructive testing. Despite being used mainly in medicine, it is becoming more and more popular as a method for monitoring of structural elements. It allows to examine the internal structure and technical condition of the tested element. This paper investigates the influence of crosssectional geometry on an obtained tomographic image. Wave propagation signals were...
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A method of earth fault loop impedance measurement without unwanted tripping of RCDs
PublicationIn low-voltage networks, earth fault loop impedance (EFLI) measurement is the basis for assessing the effectiveness of automatic disconnection of supply. Such a measurement is performed during initial and periodical verification, especially in a TN low-voltage network. Nowadays, due to widespread application of residual current devices (RCDs), such test is difficult in many circuits because RCDs operate during the test. In this...
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Calculation methods of interaction of electromagnetic waves with objects of complex geometries
PublicationModeling of the electromagnetic interaction with different homogeneous or inhomo-geneous objects is a fundamental and important problem. It is relatively easy to solve Maxwellequations analytically when the scattering object is spherical or cylindrical, for example. How-ever, when it loses these properties all that is left for us is to useapproximation models, to ac-quire the solution we need. Modeling of complex, non-spherical,...
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A new method of current limitation. Nowa metoda ograniczania prądu.
PublicationZaprezentowano nowa ideę hybrydowego, bezstykowego ogranicznika prądów zwarciowych oraz możliwości jego aplikacji. W ograniczniku tym zastąpiono łącznik zestykowy bezpiecznikiem o ultra krótkim topiku, dzięki czemu uniknięto niedogodności związanych z napędem występujących w klasycznych łącznikach hybrydowych. Rolą bezpiecznika w tym nowym zestawie jest wyłącznie zadziałanie w warunkach zwarciowych, a po przejęciu prądu...
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Investigations of size effect in concrete at aggregate level - experiments and calculations results using discrete element method
PublicationSize effect is a fundamental phenomenon in concrete. It is characterised by decreasing strength and increasing brittleness of concrete with increasing size. The thesis includes experimental and theoretical elements. The main goal of the thesis were investigations of a size effect at the aggregate level by taking fracture into account with the discrete element method (DEM) for various failure modes. Comprehensive experiments on...
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FINITE FIELDS AND THEIR APPLICATIONS
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The effect of current delay angle on tripping of residual current devices
PublicationPower electronics converters applied in domestic or similar installations may utilize current delay (phase) angle control to change the level of transferred power. Due to application of such types of converters, earth fault current in the installation may be strongly distorted. The current distortion level depends on a value of current delay angle. This delay angle also influences the tripping threshold of residual current devices....
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An Efficient PEEC-Based Method for Full-Wave Analysis of Microstrip Structures
PublicationThis article introduces an efficient method for the equivalent circuit characterization and full-wave analysis of microstrip structures, leveraging the full-wave partial element equivalent circuit (PEEC). In particular, the multilayered Green's function is evaluated using the discrete complex-image method (DCIM) and employed to establish the mixed potential integral equations. The proposed strategy considers time delays for the...
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Finite element analysis on failure of reinforced concrete corner in sewage tank under opening bending moment
PublicationW artykule omówiono mechanizm uszkodzenia żelbetowego zbiornika ściekowego w narożniku ściany, który uległ uszkodzeniu podczas próby wypełnienia na skutek nadmiernych przemieszczeń poziomych ścian pod wpływem otwierającego momentu zginającego. Aby wyjaśnić przyczyny awarii, przeprowadzono kompleksowe obliczenia metodą elementów skończonych (MES) żelbetowego zbiornika w warunkach odkształcenia płaskiego. Beton zamodelowano za pomocą...
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Measurements and calculation of self inductance of testing coils used in physical transformer model construction and its frequency analysis
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Label-free testing strategy to evaluate packed red blood cell quality before transfusion to leukemia patients
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Accelerated senescence as a cost of reproduction: Testing associations between oxidative stress and reproductive effort in rural and urban women
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Raman scattering measurements in monitoring of polymer synthesis process. Lightmetry 2002 : Metrology and Testing Techniques Using Light.
PublicationW artykule omówiono możliwości wykorzystania pomiarów ramanowskich do monitorowania w czasie rzeczywistym przebiegu procesów syntezy materiałów polimerowych. Wykorzystano sondy światłowodowe do sprzęgnięcia aparatury pomiarowej z typowym stanowiskiem technologicznym. Pomiary miały charakter zdalny, nieniszczący i niezakłócający przebieg reakcji.
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Model-Driven Testing of Real-Time Embedded Systems - From Object Oriented towards Function Oriented Development
PublicationMBD
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Detection of high frequency current components by residual current devices
PublicationThe negative impact of current harmonics on the main components of residual current devices is presented. A solution for the improvement of the operation of residual current devices is proposed.
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JOURNAL OF TESTING AND EVALUATION
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FE analysis of support-specimen interaction of compressive experimental test
PublicationThe objective of this work is to investigate the support-specimen interaction during the compressive experimental testing of stiffened plates. The interaction is analyzed employing the nonlinear Finite Element Method using the commercial software ANSYS. The connection between the stiffened plate and testing supports is modelled with the use of contact elements, where several possible interaction scenarios are investigated, and...
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Scientific Research Method
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Testing the Positioning Accuracy of GNSS Solutions during the Tramway Track Mobile Satellite Measurements in Diverse Urban Signal Reception Conditions
PublicationMobile Global Navigation Satellite System (GNSS) measurements carried out on the railway consist of using satellite navigation systems to determine the track geometry of a moving railway vehicle on a given route. Their purposes include diagnostics, stocktaking, and design work in railways. The greatest advantage of this method is the ability to perform measurements in a unified and coherent spatial reference system, which...
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Pawel Polaczyk dr inż.
PeopleDr. Pawel Polaczyk is a scholar in civil engineering and a civil engineering practitioner in pavement engineering. Dr. Polaczyk is originally from Warsaw, Poland, where he received his B.Sc. degree in Civil Engineering with a concentration in Transportation from Warsaw University of Technology. His Master`s and Doctorate degrees in Civil Engineering with a concentration in Geotechnology and Materials Engineering are from the University...
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Modal properties identification of a novel sandwich footbridge – Comparison of measured dynamic response and FEA
PublicationA modern sandwich composite footbridge made of high-tech materials, being an example of practical application of laminated composites in civil engineering, is presented. The in situ non-destructive testing of the footbridge, aiming to identify modal properties and pedestrian comfort, is described. The measured eigenmodes and eigenfrequencies are compared with numerically estimated values. Finite element analyses of the footbridge...
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Signal propagation in electromagnetic media described by fractional-order models
PublicationIn this paper, signal propagation is analysed in electromagnetic media described by fractional-order (FO) models (FOMs). Maxwell’s equations with FO constitutive relations are introduced in the time domain. Then, their phasor representation is derived for one-dimensional case of the plane wave propagation. With the use of the Fourier transformation, the algorithm for simulation of the non-monochromatic wave propagation is introduced....
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Analysis of electromagnetic disturbances in DC network of grid connected building-integrated photovoltaic system
PublicationThis paper focuses on conducted electromagnetic interference (EMI) emissions and propagation in the DC network of grid connected building integrated photovoltaic (PV) system. The investigated PV system, consists of ten solar panels, cabling and the grid-connected one phase inverter. The EMI simulation model of the real PV system has been developed with the aid of impedance analyzer measurements of solar panels and the DC network...
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Simulation of hybridized nanofluids flowing and heat transfer enhancement via 3-D vertical heated plate using finite element technique
PublicationThe present study probed the creation of heat energy and concentrating into Newtonian liquids across vertical 3D-heated plates. The role of the Soret and Dufour theories in concentrating and energy formulas is discussed. The role of hybrid nanoparticles is introduced to illustrate particle efciency in terms of solute and thermal energy. It is removed a viscous dissipation process and a changing magnetic feld. The proposed approach...
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MAGNETOACOUSTIC HEATING AND STREAMING IN A PLASMA WITH FINITE ELECTRICAL CONDUCTIVITY
PublicationNonlinear effects of planar and quasi-planar magnetosound perturbations are discussed. Plasma is assumed to be an ideal gas with a finite electrical conductivity permeated by a magnetic filed orthogonal to the trajectories of gas particles. the excitation of non-wave modes in the filed of intense magnetoacoustic perturbations, i.e., magnetoaciustic heating and streaming, is discussed. The analysis includes a derivation if instantaneous...
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Method of Skeletal System Modelling
PublicationAn original method of skeletal system modelling is presented in detail. Using DICOM images obtained from CT and PET tests, shell models of nine bones were created (humerus, radius, ulna, scapula, clavicle, femur, tibia, fibula, pelvis). Two methods of bone behaviour are also proposed, the first method treating the bone as a solid structure and the second method treating the bone as a complex porous structure. The behaviour of model...
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Filter-Hilbert Method for Automatic Correction of Non-Anechoic Antenna Measurements with Embedded Self-Calibration Mechanism
PublicationOne of the most important steps in the process of antenna development involves measurements of its prototype. Far-field performance of radiators is normally characterized in strictly controlled environments such as anechoic chambers which can ensure certification-grade accuracy. Unfortunately, they are also characterized by high construction costs which might not be justified for low-budget research and/or teaching-related activities....
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Time-Gating method with automatic calibration for accurate measurements of electrically small antenna radiation patterns in Non-Anechoic environments
PublicationNon-anechoic sites represent a cheap alternative to measurements of antennas in dedicated facilities. However, due to a high noise—from the external EM signal sources and multipath interferences—the quality of radiation patterns obtained in non-anechoic conditions is poor. The characteristics can be corrected using a time-gating method (TGM), which involves filtering of the noise based on temporal analysis of the measured signals....
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Magdalena Szuflita-Żurawska
PeopleHead of the Scientific and Technical Information Services at the Gdansk University of Technology Library and the Leader of the Open Science Competence Center. She is also a Plenipotentiary of the Rector of the Gdańsk University of Technology for open science. She is a PhD Candidate. Her main areas of research and interests include research productivity, motivation, management of HEs, Open Access, Open Research Data, information...
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Finite-window RLS algorithms
PublicationTwo recursive least-squares (RLS) adaptive filtering algorithms are most often used in practice, the exponential and sliding (rectangular) window RLS algorithms. This popularity is mainly due to existence of low-complexity versions of these algorithms. However, these two windows are not always the best choice for identification of fast time-varying systems, when the identification performance is most important. In this paper, we...
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Analysis of longitudinal wave propagation in a cracked rod by the spectral element method
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A parametric study on water-entry of a twin wedge by boundary element method
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Investigation of buckling resistance of columns using non-linear static and dynamic analysis
PublicationThe aim of this paper is to investigate the stability process in an axially compressed column using a static and dynamic finite element analysis by taking both the geometric and material non-linearity into account. The perfect column and column with geometric imperfections were analysed. The linear buckling analyses were used to obtain the lowest buckling load and shapes of buckled forms that were taken into account as initial...
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Metoda elementów skończonych w stomatologii = Finite elements method in dental surgery.
PublicationPrzedstawiono wyniki analizy możliwości zastosowania metody elementów skończonych w stomatologii. Wskazano wierunki możliwych zastosowań.
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A Diagnostic Method Based on Deflection Analysis for Monitoring Post-elastic Response of Beams
PublicationA non-destructive diagnostic method based on deflection analysis for monitoring the post-elastic response of beams was developed, and a diagnostic indicator was proposed. The indicator was defined as the second moment of the normalised curvature function about the mid-span, where the curvature was computed from the normalised deflection function. Elastic reference values of the indicator were computed for simply supported beams...
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An Efficient Simulation Method of Massive MIMO Antenna Arrays used in 5G Mobile Phones
PublicationThis paper deals with a model-order reduction method, applied to speed-up the simulations of MIMO antenna arrays, performed by means of finite element method. The obtained results of the numerical tests show that the described technique is reliable and considerably increases the efficiency of the standard finite element method.
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The description of non-linear interactions of wave and non-wave modes in a non-adiabatic plasma flow
PublicationThe method of derivation of non-linear equations for interacting modes is explained and applied to a plasma's flow affected by a magnetic field. It is based on the linear projecting of the total perturbation field into specific variations of variables in individual modes of a flow. The method may be applied in many examples of fluid flows with different mechanisms of non-adiabaticity. It is of special importance in complex flows...
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THE POSSIBILITIES OF ESTIMATING THE RELIABILITY OF SHIP PIPELINES’ ELEMENTS INCLUDING DESTRUCTIVE PHENOMENA ACTING ON THEM
PublicationIn the article an approach to the problem of estimating reliability data based on physical models is proposed. The possibility of reliability assessment for selected elements of ship pipelines, based on the recognition of the destructive physical phenomena taking place in them, is discussed. To do this, an overview of these phenomena has been made. In addition, a preliminary review of existing measures of destruction of materials...
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Non-intrusive infrared-free eye tracking method
PublicationIn the paper a technique of eye tracking based on visible light is presented. The approach described does not require an additional hardware equipment used in the infrared eye tracking system. First, examples of existing eye tracking techniques were presented. Then, the proposed algorithm of image processing and the process of determining the eye position are described. The engineered eye tracking application was tested and the...
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The modelling method of discrete-continuous systems
PublicationThe paper introduces a method of discrete-continuous systems modelling. In the proposed method a three-dimensional system is divided into finite elements in only two directions, with the third direction remaining continuous. The thus obtained discrete-continuous model is described by a set of partial differential equations. General difference equations of discrete system are obtained using the rigid finite element method. The limit...
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Testing Question Order Effects of Self-perception of Risk Propensity on Simple Lottery Choices as Measures of the Actual Risk Propensity
PublicationUncertainty together with the necessity of making choices inevitably results in risky decisions. For many years now, scientists have been studying notions connected with risk such as risk management, risk perception or risk propensity. While many sophisticated methods regarding measurement of risk propensity have been developed so far, it seems that little attention has been paid to checking whether they are not inherently flawed....
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Chassis Dynamometer Testing of Ammonia Emissions from Light-Duty SI Vehicles in the Context of Emissions of Reactive Nitrogen Compounds
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A chamber for testing the release of volatile substances secreted by animals, especially mammals, as exemplified by substances released by rats in response to stress
PublicationPowodzenie badań lotnych związków organicznych emitowanych przez zwierzęta zależy od stworzenia odpowiednich warunków do pobierania próbek używanych do ich izolacji i identyfikacji. Warunki te odgrywają ważną rolę w badaniach feromonów, które występują na bardzo niskich poziomach stężeń. W dostępnej literaturze autorzy nie znaleźli rozwiązania pozwalającego uniknąć zanieczyszczenia pobieranych próbek powietrza zawierających lotne...
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Performance improvement method for the voltage-fed qZSI with continuous input current
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Electromagnetic Problems Requiring High-Precision Computations
PublicationAn overview of the applications of multiple-precision arithmetic in CEM was presented in this paper for the first time. Although double-precision floating-point arithmetic is sufficient for most scientific computations, there is an expanding body of electromagnetic problems requiring multiple-precision arithmetic. Software libraries facilitating these computations were described, and investigations requiring multiple-precision...
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METHOD OF TRAINING THE ENDOSCOPIC VIDEO ANALYSIS ALGORITHMS TO MAXIMIZE BOTH ACCURACY AND STABILITY
PublicationIn the article a new training and testing method of endoscopic video analysis algorithms is presented. Classical methods take into account only eciency of recognizing objects on single video frames. Proposed method additionally considers stability of classiers output for real video input. The method is simple and can be trained on data sets created for other solutions. Therefore, it is easily applicable to existing endoscopic video...
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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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A novel formulation of 3D spectral element for wave propagation in reinforced concrete
PublicationThe paper deals with numerical simulations of wave propagation in reinforced concrete for damage detection purposes. A novel formulation of a 3D spectral element was proposed. The reinforcement modelled as the truss spectral element was embedded in the 3D solid spectral finite element. Numerical simulations have been conducted on cuboid concrete specimens reinforced with two steel bars. Different degradation models were considered...
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Testing impedance analyzer with potentiostat using RC model with Si diode at 200 mV
Open Research DataThe dataset presents impedance spectrum non-linear RC model with diode presented in the figure below. This model was used as a test engine of the impedance analyzer with potentiostat described in the referenced paper. When changing the DC polarisation of the model the non-linear phenomena could be observed. Thanks to this, the model can be used as a...