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Search results for: jumping wave
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A concept of measurement system based on the Z-Wave standard
PublicationIn the paper a new concept of measurement system based on the Z-Wave standard is presented. This standard is dedicated to use mainly in home automation systems, but its properties enable to use it in dispersed measurement systems and support wireless communication between measurement nodes in a mesh-type network. In the paper basic metrological aspects of the Z-Wave standard and an example of impedance measurement system are discussed.
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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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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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Measurement system based on USB Z-Wave controller
PublicationA wireless measurement system based on the Z-Wave standard is presented in this paper. The system is composed of a U SB Z-Stick Gen5 controller connected to a Personal Computer and a Fibaro controller FGRGBWM-441. Operation of the system is controlled by software written in C++ using OpenZWave library. Some metrological aspects of the system are evaluated: accuracy, linearity, resolution and frequency of voltage measurements.
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Multiobjective Water Distribution Systems Control of Pumping Cost, Water Quality, and Storage-Reliability Constraints
PublicationThis work describes a multiobjective model for trading-off pumping cost and water quality for water distribution systems operation. Constraints are imposed on flows and pressures, on periodical tanks operation, and on tanks storage. The methodology links the multiobjective SPEA2 algorithm with EPANET, and is applied on two example applications of increasing complexity, under extended period simulation conditions and variable energy...
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Pumping effect measured by PIV method in a multilayer spike electrode EHD device for air cleaning
PublicationDust particles can be harmful for human health when inhaled. Particularly dangerous are submicrometer dust particles, which can contain traces of toxic elements and can easily penetrate into the human respiratory system. Thus, efficient devices for the air cleaning from submicrometer dust particles are needed. Recently, Katatani and Mizuno have proposed an electrohydrody- namic (EHD) device for air cleaning for submicrometer particles....
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Nonlinear rate dependent model of high damping rubber bearing.
PublicationCelem artykułu jest analiza nieliniowego modelu łożyska wykonanego z wysokotłumiącej gumy, który symuluje pracę urządzenia pod zadanym obciążeniem. Parametry modelu dobrane są na podstawie wyników badań eksperymentalnych. Wyniki pracy pokazują, iż analizowany model umożliwia symulację zachowania się łożyska w szerokim zakresie odkształceń
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Transient response of oscillated carbon nanotubes with an internal and external damping
PublicationThe present works aims at modeling a viscoelastic nanobeam with simple boundary conditions at the two ends with the introduction of the Kelvin-Voigt viscoelasticity in a nonlocal strain gradient theory. The nanobeam lies on the visco-Pasternak matrix in which three characteristic parameters have a prominent role. A refined Timoshenko beam theory is here applied, which is only based on one unknown variable, in accordance with the...
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Selective jamming of OFDM transmission in NB-IoT radio interface
PublicationThe paper presents the concept of smart jamming, which involves selective interference aimed at critical components of the OFDM signal. Research verifying the feasibility of this type of electronic attack are described. A realized testbed for jamming real NB-IoT signals in a downlink is presented. The test results demonstrate the feasibility of realizing selective jamming and its greater effectiveness compared to barrage interference.
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Waves in Random and Complex Media
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COMBUSTION EXPLOSION AND SHOCK WAVES
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JOURNAL OF INFRARED AND MILLIMETER WAVES
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JOURNAL OF CAVE AND KARST STUDIES
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Pumping effect measured by PIV method in multi-layer spike electrode EHD device for air cleaning
PublicationDust particles can be harmful for human health when inhaled. Especially dangerous are submicron dust particles, which can contain traces of toxic elements and can easily penetrate into human respiratory system. Thus, new devices for air cleaning are needed. In this work the flow velocity field patterns measured by Particle Image Velocimetry (PIV) method in an electrohydrodynamic (EHD) device for air cleaning are presented. The...
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Multi-Objective Water Distribution Systems Control of Pumping Cost, Water Quality, and Storage-Reliability Constraints
PublicationThis work describes a multi-objective model for trading-off pumping cost and water quality for water distribution systems operation. Constraints are imposed on flows and pressures, on periodical tanks operation, and on tanks storage. The methodology links the multi-objective SPEA2 algorithm with EPANET, and is applied on two example applications of increasing complexity, under extended period simulation conditions and variable...
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Seawater intrusion due to pumping mitigated by natural freshwater flux: a case study in Władysławowo, northern Poland
PublicationThe paper presents a case study of seawater intrusion into a coastal aquifer, caused by a groundwater intake located close to the seashore in Władysławowo, northern Poland. Evolution of the basic hydrogeochemical parameters for the 50-year period from 1964 to 2014 indicates progressing encroachment of saline seawater into the aquifer. However, the spatial pattern of salinity was influenced by the variability of hydraulic gradient...
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WAVE AND CURRENT MODELLING OVER THE BALTIC SEA AND THE GDAŃSK BAY
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Slow-wave fractal-shaped compact microstrip resonant cell
PublicationA novel fractal-shaped compact microstrip resonant cell (CMRC) featuring a strong slow-wave effect has been presented. Its vital usefulness in the process of microstrip line miniaturisation has been proved and experimentally validated on the basis of a compact 3-dB branch-line coupler illustrating the possibilities of the approach. A prototype example structure has been designed to mirror the characteristics of a conventional device,...
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Radio wave propagation conditions for terrestrial radiocommunications in the EHF band
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Spectral Wave Energy Dissipation due to Under-Ice Turbulence
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Research on wave structures containing sets of metallized cylindrical objects
PublicationCel pracy obejmował opracowanie modelu matematycznego opartego na bezpośredniej interpretacji fizycznej rozpraszania fali elektromagnetycznej w zamkniętych i otwartych systemach zawierających różne konfiguracje złożonych obiektów cylindrycznych. Kolejnym celem było zastosowanie otrzymanego modelu do badania problemów otwartych i zamkniętych, oraz zaproponowanie przykładów ich aplikacji. Tezą pracy było stwierdzenie, że istnieje...
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Numerical modelling of conical wave formation in multimode optical fibers
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Characteristics of the s–Wave Symmetry Superconducting State in the BaGe3 Compound
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Damage localisation in a stiffened plate structure using a propagating wave
PublicationThe paper presents an application of changes in propagating waves for damage detection in a stiffened aluminium plate. The experimental investigation was conducted on an aluminium plate with riveted two L-shape stiffeners. The wave has been excited with a piezoelectric transducer and measured with the Laser Scanning Doppler Vibrometer. Recorded signals were analysed using the special signal processing techniques developed for damage...
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ENHANCED EVAPORATION OF THE DROPLETS OF CONDENSATE IN THE ASYMMETRICAL SHOCK WAVE ZONE
PublicationIn the low-pressure part of steam turbine, the state path usually crosses the saturation line in penultimate stages [4,5]. The formation and evolution of these droplets lower the performance of the wet stages of the turbines, and their effects on the efficiency are collectively known as wetness losses [4]. Nowadays, due to work of steam turbines at partial load, process of homogeneous and heterogeneous condensation still is current....
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Oblique Plane Wave Scattering by an Array of Dielectric and Metamaterial Cylinders.
PublicationBadanie wpływu ujemnej przenikalności elektrycznej i magnetycznej na parametry rozproszenia fali elektromagnetycznej dla cylindrów wykonanych z dielektryka i metamateriału. Wykorzystanie zmodyfikowanej procedury iteracyjnej i metody dopasowania rodzajów do analizy ukośnego padania fali elektromagnetycznej na zbiór równoległych cylindrów.
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Nonlinear evolution of components of electromagnetic field of helicoidal wave in plasma
PublicationWyprowadzilismy model równań opisujących oddziaływanie pomiedzy kołowo spolaryzowanymi paczkami fal helikoidalnych w dwuwymiarowej plazmie. Dla quasi-jednowymiarowego przypadku otrzymaliśmy warunek nieliniowego rezonansu dla oddziaływania N-fal. Nowym ''osiągnięciem'' badań w kontekscie teorii solitonów, jest znalezienie rozwiązań dla przypadku asynchronizmu fal, które wydaje się być podstawowym dla paczek falowych nachylonych...
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Longitudinal wave propagation. Part II, Analysis of crack influence
PublicationW pracy analizowano wpływ pęknięć zmęczeniowych na propagacje fali wzdłużnej w prętach. Opracowano nowe typy element ów spektralnych oparte na teorii elementarnej, Love'a, Mindlina i trójpostaciowej.
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Longitudinal wave propagation. Part I - Comparison of rod theories
PublicationW pracy przedstawiono modele spektralnych elementów skończonych do analizy propagacji fali wzdłuznej w pretach. Opracowano modele wykorzystujace teorię elementarną, teorie Love'a, teorie Mindlina oraz teorię trójpostaciową.
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Characterization of wave structures containing sets of bow-tie resonators
PublicationArtykuł opisuje metodę analizy rozpraszania fali elektromagnetycznej układzie rezonatorów motylkowych w strukturach otwartych i zamkniętych. W artykule zaprezentowano przykłady aplikacji układów mikrofalowych zawierające opisywane elementy.
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Radiation phenomena from pseudochiral cylinders at plane wave incidence
PublicationPrzedstawiono wpływ materiałów pseudochiralnych na charakterystyki rozproszenia fali elektromagnetycznej od obiektów cylindrycznych. W celu zbadania zjawisk rozproszenia zastosowano kombinacje iteracyjnej procedury rozproszenia i metodę dopasowania rodzajów. Wpływ zastosowania materiałów pseudochiralych w konfiguracjach obiektów cylindrycznych zaprezentowano na charakterystykach pola rozproszonego w strefie dalekiej oraz na charakterystykach...
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Damage detection in elements of strutures by the elastic wave propagation method.
PublicationW pracy przedstawiono wyniki badań dotyczace wykorzystania fal sprężystych do detekcji uszkodzeń i jedno i dwu wymiarowych elementach konstrukcyjnych.
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Five-phase induction motor drive with sine-wave filter
PublicationThe paper presents closed loop ac drive with 5 phase induction motor operating with voltage source inverter and sine wave filter. The motor supply voltages and currents have sinusoidal shape. For well known adjustable electric drives the field oriented control method with flux and speed co ntrol can be applied. In the presence of output filter both control and estimation algorithms should be modified due to sine wave filter installation....
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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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Application of guided wave propagation in diagnostics of steel bridge components
PublicationEarly detection of potential defects and identification of their location are necessary to ensure safe, reliable and long-term use of engineering structures. Non-destructive diagnostic tests based on guided wave propagation are becoming more popular because of the possibility to inspect large areas during a single measurement with a small number of sensors. The aim of this study is the application of guided wave propagation in...
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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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Multi-objective weather routing of sailboats considering wave resistance
PublicationThe article presents a method to determine the route of a sailing vessel with the aid of deterministic algorithms. The method assumes that the area in which the route is to be determined is limited and the basic input data comprise the wind vector and the speed characteristic of the vessel. Compared to previous works of the authors, the present article additionally takes into account the effect of sea waves with the resultant resistance...
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Nonlinear Properties of Seawater as a Factor Determining Nonlinear Wave Propagation
PublicationTaking practical advantage of nonlinear acoustical interactions occurring in seawater [1, 2] requires knowledge of the parameter of nonlinearity B=A of this medium. The literature does not offer much reports on B=A parameter value for seawater. In the few papers concerning that address the issue, results concerning ocean waters with high salinity and at large depths are given [3], while studies concerning seawater with low salinity...
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Scattering of the plane wave from a periodically perforated dielectric slab
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Longitudinal wave propagation. Part I—Comparison of rod theories
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Longitudinal wave propagation. Part II—Analysis of crack influence
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Numerical analysis of the finite amplitude plane wave propagation problem
PublicationRozważano zagadnienie propagacji fali płaskiej o skończonej amplitudzie w środowisku wodnym. Przedstawiono model matematyczny i przykładowe wyniki obliczeń numerycznych. Model matematyczny zbudowano w oparciu o równanie akustyki nieliniowej. Do rozwiązania zagadnienia zastosowano metodę różnic skończonych. Badano wpływ wartości parametrów numerycznych na dokładność obliczeń oraz analizowano wpływ wartości parametrów fizycznych...
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Domain Reduction in Hybrid Technique for Electromagnetic Wave Scattering Problems
PublicationThis paper proposes a combination of the field matching technique, finite element method and generalized impedance matrix, the main idea of which is to reduce the computational domain by surrounding a scatterer with the smallest convex shape and applying the field matching technique. This approach can be applied for arbitrary shaped scatterers and types of materials and allows for the reduction of the computational domain. In order...
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Simulation of Wave Propagation in Media Described by Fractional-Order Models
PublicationIn 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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Damage Imaging in Lamb Wave-Based Inspection of Adhesive Joints
PublicationAdhesive bonding has become increasingly important in many industries. Non-destructive inspection of adhesive joints is essential for the condition assessment and maintenance of a structure containing such joints. The aim of this paper was the experimental investigation of the damage identification of a single lap adhesive joint of metal plate-like structures. Nine joints with different defects in the form of partial debonding...
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Underwater Navigation System Based on Doppler Shifts of a Continuous Wave
PublicationThe paper describes a concept of an underwater navigation system designed to determine the location and speed of its ROVs or divers. Conducted by the Department of Marine Electronic Systems at the Gdansk University of Technology for several years, research has focused on navigation systems which determine positions on the basis of Doppler shifts of echo signals reflected from a moving object. This article presents a different version...
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Detection of debonding in adhesive joints using Lamb wave propagation
PublicationAdhesively bonded joints are widely used in many branches of industry. Mechanical degradation of this type of connections does not have significant symptoms that can be noticed during visual assessment, so non-destructive testing becomes a very important issue. The paper deals with experimental investigations of adhesively bonded steel plates with different defects. Five samples (an intact one and four with damages in the form...
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Charge density wave and large nonsaturating magnetoresistance in YNiC2 and LuNiC2
PublicationWe report a study of physical properties of two quasi-low-dimensional metals YNiC2 and LuNiC2 including the investigation of transport, magnetotransport, galvanomagnetic, and specific heat properties. In YNiC2 we reveal two subsequent transitions associated with the formation of weakly coupled charge density wave at TCDW=318K and its locking in with the lattice at T1=275K. These characteristic temperatures follow the previously...
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Preload monitoring in a bolted joint using Lamb wave energy
PublicationThe knowledge of the load in prestressed bolted connections is essential for the proper operation and safety of engineering structures. Recently, bolted joints have become an area of intensive research associated with non-destructive diagnostics, in particular in the context of wave propagation techniques. In this paper, a novel procedure of bolt load estimation based on the energy of Lamb wave signals was proposed. Experimental...
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Numerical Study of Concrete Mesostructure Effect on Lamb Wave Propagation
PublicationThe article presents the results of the numerical investigation of Lamb wave propagation in concrete plates while taking into account the complex concrete mesostructure. Several concrete models with randomly distributed aggregates were generated with the use of the Monte Carlo method. The influence of aggregate ratio and particle size on dispersion curves representing Lamb wave modes was analyzed. The results obtained for heterogeneous...