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Wyniki wyszukiwania dla: MILLIMETER WAVE
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Local dynamics of fluids and dielectrics as the foundation of signal-carrying wave properties
PublikacjaThis paper develops an original approach to fundamental problems of classical linear acoustics and electromagnetics, proving a crucial role of doubly-dynamic local properties of a propagation medium in supporting wave-like fields able to carry information signals. The proof is composed of two steps concerning, subsequently, fluid acoustics and dielectric electromagnetics. The first step consists in complementing a common, practically...
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Verification of algorithms determining wave loads on support structure of wind turbine
PublikacjaThe offshore wind turbines require determination of wave loads on their support structure. This structure is fixed and, therefore, this problem is reduced to solving only the diffraction problem, which is determined by Laplace equation and conditions on the following boundaries: on the support structure, on the sea free surface and on its bottom, and at infinity on free surface. The linear problem was applied to determine the wave...
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Impact of radio wave polarisation on off-body communications in indoor environments
PublikacjaThis paper describes the measurements and the analysis of the impact of radio wave polarisation on off-body communications in Body Area Networks in indoor environments. Measurements on polarisation impact are briefly described. Five investigated scenarios with different body postures and different antenna placements are characterised. The difference between the vertical and horizontal components of the received radio signal are...
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Ground anchors diagnostic process based on elastic wave propagation method
PublikacjaThe paper is focused on analysis of elastic wave propagation in the context of diagnostics of ground anchors. Numerical simulations were performed to assess the possibility of evaluation of the anchorage quality. It was assumed that the quality and the load capacity of the anchor system directly depend on the length, on which mortar and steel cooperate.
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Research on assessment of bolted joint state using elastic wave propagation
PublikacjaThe work contains results of experimental investigation of elastic wave propagation in a bolted single-lap joint. Tests were carried out for the excitation perpendicular to the connection plane. In experimental studies, PZT transducers were used for both excitation and registration of ultrasonic waves. The analyses took into account varying contact conditions between the elements of the connection depending on the value of the...
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Basic ideas and advantages of the method of analytical regularization in wave optics: Overview
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Analysis of longitudinal wave propagation in a cracked rod by the spectral element method
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On the design of planar high directivity proximity couplers in the mm-wave range
PublikacjaPrzedyskutowano problemy projektowania sprzęgaczy zbliżeniowych wykonywanych w technologii planarnej i przeznaczonych do pracy w zakresie fal milimetrowych. Zasadniczym celem badań było zaprojektowanie, wykonanie i przebadanie układu sprzęgacza o wysokiej kierunkowości i umiarkowanym poziomie sprzężenia pracującego w zakresie 40-50GHz. Przedyskutowano i zamodelowano różne konfiguracje sprzęgaczy. Stwierdzono, że znane zasady projektowania...
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On some properties of 2d spectral finite elements in problems of wave propagation
PublikacjaW pracy przedstawiono sformułowanie dwuwymiarowych elementów spektralnych stosowanych w symulacji propagacji fal prowadzonych. Zbadano własności tych elementów pod kątem występowania form pasożytniczych, odporności na dystorsję siatki oraz zbadano wpływ kształtu elementu na krzywe dyspersji
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System setup and software for cyclic, staircase and square wave voltammetry measurements
PublikacjaHardware dedicated for electrochemical measurement sometimes does not allow performing certain voltammetry experiments. Staircase and square wave voltammetry, techniques which have many advantages comparing with standard voltammetric techniques, are rarely implemented in software controlling electrochemical measuring equipment. These methods, however, can be relatively easy realized with some addition...
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Non-Wave Variations in Temperature Caused by Sound in a Chemically Reacting Gas
PublikacjaA weakly nonlinear generation of non-acoustic modes in the field of sound in a gas is considered. An exotericchemical reaction of A->B type, which takes place in a gas, may be reversible or not. Two types of sound areconsidered, low-frequency and high-frequency as compared with the characteristic time of a chemical reaction.For both these cases, the governing equations of non-acoustic modes are derived and conclusions of the efficiencyof...
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Rectangular microstrip resonator illumi-nated by normal-incident plane wave
PublikacjaW pracy przedstawiono koncepcję modów oświetlających pozwalającą na obliczenie podstawowych parametrów elektrycznych anten mikropaskowych - częstotliwości rezonansowej, rezystancji promieniowania i charakterystyki promieniowania. Oparta jest ona na dwuwymiarowej metodzie przestrzeni widmowej, w której pobudzenie występuje w formie pojedynczej fali płaskiej padającej prostopadle na analizowaną strukturę. Rezultatem takiego podejścia...
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Electromagnetic wave scattering from material objects using hybrid methods
PublikacjaRozdział zawiera opis hybrydowych metod analizy stanowiących połączenie metody różnic skończonych w dziedzinie częstotliwości (FDFD) z metodą dopasowania rodzajów (MM), służących do badania cylindrycznych struktur falowych w układach zamkniętych i otwartych.
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Testing the impact of simplifications adopted in models describing wave loads on ship
PublikacjaThe wave-ship system in naval architecture is generally assumed to be a linear one. This allows for the computation of a transfer function of ship response to waves including wave loads on ship. The transfer function and the wave spectral density function enable the development of the stochastic process of wave loads on ship, corresponding to the irregular wave generating that loads. If the mathematical models of wave load transfer...
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Testing the impact of simplifications adopted in models describing wave loads on ship
PublikacjaThe wave-ship system in naval architecture is generally assumed to be a linear one. This allows for the computation of a transfer function of ship response to waves including wave loads on ship. The transfer function and the wave spectral density function enable the development of the stochastic process of wave loads on ship, corresponding to the irregular wave generating that loads. If the mathematical models of wave load transfer...
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Elastic wave propagation for condition assessment of steel bar embedded in mortar
PublikacjaThis 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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Guided wave propagation for assessment of adhesive bonding between steel and concrete
PublikacjaAdhesive bonding is becoming more increasingly important in joining of structural elements. In civil engineering, there is a growing interest in connection by adhesive bonding in steel-concrete flexural members. This study concerns the guided wave propagation technique applied to condition assessment of an adhesive connection between a steel member and a concrete beam. Various states of degradation were considered by producing...
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Lamb wave-based monitoring of shear failure of an adhesive lap joint
PublikacjaThe paper presents a study on the elastic wave propagation in adhesive joints of steel plates subjected to tensile loading. A single lap joint was chosen for analysis because of its simplicity and plurality of applications. Experimental investigations consisted of the uniaxial extension of prepared specimens. Force and displacement values were recorded by a testing machine. Simultaneously, guided Lamb waves were excited and signals...
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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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Design solution and selected research results of the sea-wave energy converter
PublikacjaW artykule przedstawiono oryginalne rozwiązanie konstrukcyjne boi do pozyskiwania energii fal morskich oraz analizy i badania modelowe turbiny wodnej poprzedzające wybór ostateczny konstrukcji modelu boi w skali 1:5 przewidzianego do badań eksperymentalnych w basenie holowniczym. Zaprezentowano także wybrane wyniki badań modelowych i symulacji komputerowych ukazujący wpływ systemu kotwiczenia i innych parametrów na jakość i efektywność...
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Fast Full-Wave Multilevel Zero-Pole Optimization of Microwave Filters
PublikacjaA new concept is proposed for the full-wave computer-aided design of microwave filters. The method consists of two stages and operates on the zeros and poles of the transfer function and their derivatives. These quantities are evaluated from the response computed by a full-wave electromagnetic solver with two levels of accuracy. The two stages make use of different models that are optimized using a low-accuracy electromagnetic...
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Detection and size estimation of crack in plate based on guided wave propagation
PublikacjaThe paper presents results of the comprehensive theoretical and experimental investigation of crack detection in metallic plate using guided wave propagation. The main aim of the paper is to develop the novel method which would allow for linear crack size estimation with the use of minimal number of the transducers. In general, there exists the relation between length of the propagation path and the wave amplitude value. However,...
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A novel formulation of 3D spectral element for wave propagation in reinforced concrete
PublikacjaThe 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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An Experimental Investigation of Pressure Wave Celerity During the Transient Slurry Flow
PublikacjaTransportation of slurries in pressure pipelines is an example of a complex flow due to specific parameters of transported medium. For practitioners, the economy of designing and maintenance is usually the most important factor. For this reason, most of hydrotransport installations are fairly simple; however, they become more vulnerable to negative effects of the transient flow which can occur in pressure pipelines. As the consequence,...
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Numerical investigation of the core eccentricity effect on wave propagation in embedded waveguide
PublikacjaThe paper presents results of theoretical and numerical investigation of guided wave propagation in two-layer bars with geometric imperfections in the form of eccentric location of steel core. Steel rod of diameter equal to 1 cm embedded in composite mortar-type cover with external diameter equal to 5 cm has been taken into consideration. Several different rods with variable size of eccentricity are analysed. Results for rods with...
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Guided Wave Propagation in Detection of Partial Circumferential Debonding in Concrete Structures
PublikacjaThe following article presents results of investigating the damage detection in reinforced concrete beams with artificially introduced debonding between the rod and cover, using a non-destructive method based on elastic waves propagation. The primary aim of the research was to analyze the possible use of guided waves in partial circumferential debonding detection. Guided waves were excited and registered in reinforced concrete...
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Debonding Detection in Reinforced Concrete Beams with the Use of Guided Wave Propagation
PublikacjaOne of the most frequent damage of the reinforced concrete structures is debonding between steel bar and concrete cover. In the case of debonding occurrence not only the strength of the structure decreases, but also it is more vulnerable to corrosion damages. For this reason fast and effective methods of debonding detection in an early stage of its development need a significant boost. The paper presents analytical and experimental...
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Application of the ISE Optimized Proportional Control of the Wave Maker in a Towing Tank
PublikacjaThis paper presents the improvement of the wave maker control system. The wave maker is a facility widely used in hydromechanics laboratories to generate waves in towing tanks. It is equipped with an electrohydraulic drive and an actuator submerged into water. The waves are generated to model the environmental conditions for physical experiments, performed on reduced-scale models of maritime objects. The physical experiments allow...
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Electromagnetic wave scattering by a set of axially symmetric omega-medium cylinder
PublikacjaZaprezentowano analizę rozproszenia fali elektromagnetycznej od układu obiektów cylindrycznych zbudowanych z materiałów pseudochiralnych, umieszczonych w złączach falowodowych lub wolnej przestrzeni. Analiza bazuje na iteracyjnej procedurze rozproszenia i metodzie dopasowania rodzajów.
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Mind the Gender Wage Gap – the Impact of Trade and Competition on Sectoral Wage Difference
PublikacjaThis article examines differences between women’s and men’s wages in 18 selected OECD countries in the period 1970-2005. The study is based on 12 manufacturing sector- and skill-specific sets of panel data on the gender wage gap. We apply a system GMM estimator to the extended version of the conditional gender wage gap convergence equation, controlling for sector concentration and industry-specific measures of openness using a...
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Acousto-optic interaction of a Gaussian laser beam with an ultrasonic wave of cylindrical symmetry
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Pulse wave velocity is associated with early clinical outcome after ischemic stroke
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Modelling of wave propagation in spatial frame elements - numerical simulations and experimental works
PublikacjaW pracy porównano rozwiązania propagacji fal sprężystych w ośrodku typu belka Timoszenki, uzyskane na drodze eksperymentalnej i numerycznej. Do obliczeń numerycznych wykorzystano wielowęzłowe spektralne elementy skończone klasy C0.Omówiono algorytm całkowania po czasie i sformułowano wnioski dotyczące liczby węzłów na długość fali.
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Fibrinogen and d-dimer in contrasting relation with measures of wave reflection and arterial stiffness
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Pulse wave velocity to the global longitudinal strain ratio in survivors of myocardial infarction
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Assessment of the effect of vegetation on the transition of the flood wave using hydraulic 2D models
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Variational ansatz for p-wave fermions confined in a one-dimensional harmonic trap
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Shock wave - boundary layer interaction control by air-jet streamwise vortices
PublikacjaW pracy przedstawiono wyniki badań eksperymentalnych i numerycznych oddziaływania fali uderzeniowej z warstwą przyścienną. Badania eksperymentalne wykonano dla różnych geometrii dysz. Przedstawiono wpływ generatorów wirów wzdłużnych na strukturę przepływu i możliwość kontrolowania oderwania za falą uderzeniową. Przeprowadzono optymalizację konfiguracji generatora wirów w przepływie naddźwiękowym w oparciu wyniki obliczeń przepływu...
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Piecewise continuous distribution function method in the theory of wave disturbances of inhomogeneous gas
PublikacjaUkład równań typu hydrodynamicznego dla warstwowych gazów w polu grawitacyjnym pochodzi od równania BGK metodą częściowej ciągłej funkcji dystrybucji. Otrzymany system równań uogólnia układ Naviera-Stokesa w dowolnych liczbach Knudsena.
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Design of quarter-wave compact impedance transformers using coupled transmission lines
PublikacjaPrzedstawiono porównanie wyników symulacji jedno i wielosekcyjnych transformatorów impedancji budowanych w postaci struktur wykorzystujących idealnenie sprzężone linie transmisyjne, idealne sprzężone symetryczne linie transmisyjne oraz rzeczywiste sprzężone linie mikropaskowe. Pokazano, że możliwa jest konstrukcja transformatorów impedancji o bardzo dobrych parametrach technicznych wykorzystująca sprzężone linie mikropaskowe, pomimo...
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Response of the local pair superconductor to the static vector potential at finite wave length
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Impact of sea wave stochastic characteristics on ship propulsion control system design.
PublikacjaWybrano do rozważań (symulacji komputerowej) 8 rejonów morskich w 4 porach roku. Określono w nich gęstość widmową amplitudy fali morskiej. Założono, upraszczająco, regulator typu PID. Dla wybranego typu statku wykonane badania symulacyjne odnoszą się do wybranych rejonów mórz i pór roku. Okazuje się, że dobierając zarówno współczynnik wzmocnienia regulatora jak i stałą całkowania, można minimalizować wartości wariancji, na przykład,...
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Continuous wave sonar with hyperbolic frequency modulation keyed by pseudo-random sequence
PublikacjaA CW FM type sounding signal is used in the classical solution of silent sonar. While the signal provides a relatively simple implementation of digital signal processing, and ensures good detection conditions, unfortunately, in the presence of the Doppler effect, distance measurement results tend to be wrong. This is due to the fact that the received signal’s instantaneous frequency value is dependent both on the distance to the...
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Design of an Autonomous IoT Node Powered by a Perovskite-Based Wave Energy Converter
PublikacjaThis paper presents the results of experimental research focused on wave energy harvesting and its conversion to power Internet of Things (IoT) devices. The harvesting and conversion process was performed using a wave energy converter (WEC) consisting of a lead zirconate titanate piezoelectric ceramic perovskite material and a prototype power electronic circuit. The designed WEC was considered as a power supply for an end node...
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Nondestructive corrosion degradation assessment based on asymmetry of guided wave propagation field
PublikacjaThe article presents the results of numerical and experimental investigation of guided wave propagation in steel plates subjected to corrosion degradation. The development of novel procedures allowing for the assessment of the corrosion degradation level is crucial in the effective diagnostics of offshore and ship structures that are especially subjected to aggressive environments. The study’s main aim is to investigate the influence...
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Investigating Fuel Injection Strategies to Enhance Ship Energy Efficiency in Wave Conditions
PublikacjaThe 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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Cointegration approach for temperature effect compensation in Lamb-wave-based damage detection
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Ultrafast Intramolecular Relaxation and Wave-Packet Motion in a Ruthenium-Based Supramolecular Photocatalyst
PublikacjaThe hydrogen-evolving photocatalyst [(tbbpy)2 Ru(tpphz)Pd(Cl)2 ](2+) (tbbpy=4,4'-di-tert-butyl-2,2'-bipyridine, tpphz=tetrapyrido[3,2-a:2',3'-c:3'',2''-h:2''',3'''-j]phenazine) shows excitation-wavelength-dependent catalytic activity, which has been correlated to the localization of the initial excitation within the coordination sphere. In this contribution the excitation-wavelength dependence of the early excited-state relaxation...
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Measurement and Analysis of the Radio Wave Polarisation in Off-Body Communications in Indoor Environment
PublikacjaThe paper describes an analysis of the radio wave polarisation in off-body communications in indoor environment. The measurement stand for polarisation measurements has been shortly described. Five investigated scenarios with different body postures and different antenna placements have been characterize. The vertical and horizontal components of received radio signal have been analysed. The measure used in analysis is a ratio...
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The spectral finite element model for analysis of flexural–shear coupled wave propagation
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