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Search results for: PLANE WAVE PROPAGATION
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Design of an Autonomous IoT Node Powered by a Perovskite-Based Wave Energy Converter
PublicationThis 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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Propagation Characteristics of Partial Discharges in an Oil-Filled Power Transformer
PublicationPower transformers are among the most important assets in the power transmission and distribution grid. However, they suffer from degradation and possible faults causing major electrical and financial losses. Partial discharges (PDs) are used to identify the insulation health status and their degradation level. PDs are incipient, low-magnitude faults caused by localized dielectric breakdown. Those activities emit signals in many...
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System setup and software for cyclic, staircase and square wave voltammetry measurements
PublicationHardware 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-Perfect Propagation of Information to a Noisy Environment with Self-Evolution
PublicationWe study the non-perfect propagation of information for evolving a low-dimensional environment that includes self-evolution as well as noisy initial states and analyse the interrelations between the degree of objectivization and environment parameters. In particular, we consider an analytical model of three interacting qubits and derive its objectivity parameters. The numerical analysis shows that the quality of the spectrum broadcast...
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Simulating coherent light propagation in a random scattering materials using the perturbation expansion
PublicationMultiple scattering of a coherent light plays important role in the optical metrology. Probably the most important phenomenon caused by multiple scattering are the speckle patterns present in every optical imaging method based on coherent or partially coherent light illumination. In many cases the speckle patterns are considered as an undesired noise. However, they were found useful in various subsurface imaging methods such as...
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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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An Experimental Investigation of Pressure Wave Celerity During the Transient Slurry Flow
PublicationTransportation 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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Application of the ISE Optimized Proportional Control of the Wave Maker in a Towing Tank
PublicationThis 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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Verification of algorithms determining wave loads on support structure of wind turbine
PublicationThe 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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Coda wave interferometry in monitoring the fracture process of concrete beams under bending test
PublicationEarly detection of damage is necessary for the safe and reliable use of civil engineering structures made of concrete. Recently, the identification of micro-cracks in concrete has become an area of growing interest, especially using wave-based techniques. In this paper, a non-destructive testing approach for the characterization of the fracture process was presented. Experimental tests were made on concrete beams subjected to mechanical...
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Assessment of image processing methods for the determination of propagation of squat-type defects in rails
PublicationWe demonstrate the idea of squat-type defect measurement in the rail and the concept of tracking of the defect development using the techniques of image acquisition and image processing as well as the methods of metric spaces. We introduce the concepts of a set diameter δ(A) and the metric ρ1, which come from the properties of plane figures, to compare and to observe the development of the defects. We characterize the feasibility...
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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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Investigation of the laser generated ablation plasma plume dynamics and plasma plume sound wave dynamics
PublicationWe investigated the dynamics of laser generated ablation plasma plume expanding in ambient air and dynamics of the sound wave generated by the expanding plasma. The ablation plasma plume was generated during nanosecond laser micromachining of the thin metal foil. The time-resolved images of the expanding plasma plume and sound wave were captured at several nanosecond intervals. Using captured images the expansion rate of the plasma...
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Instrumented end notched flexure - Crack propagation and process zonemonitoring Part II: Data reduction and experimental
PublicationA mode II instrumented end notched flexure three point bending (ENF) adhesion test is described. The adhesive joint consists of two aluminium alloy (AW7075-T6) plates bonded with a structural epoxy adhesive (Hysol EA 9395™). Strain gauges are attached to the outer surface (backface) of the substrates in the lengthwise direction to measure local surface strain during crack propagation. Simultaneously, load/displacement measurements...
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Giant Nernst effect in the incommensurate charge density wave state of P4W12O44
PublicationWe report the study of Nernst effect in quasi-low-dimensional tungsten bronze P4W12O44 showing a sequence of Peierls instabilities. We demonstrate that both condensation of the electronic carriers in the charge density wave state and the existence of high-mobility electrons and holes originating from the small pockets remaining in the incompletely nested Fermi surface give rise to a Nernst effect of a magnitude similar to that...
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Effective anti-plane properties of piezoelectric fibrous composites
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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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SELECTION OF REFERENCE PLANE BY THE LEAST SQUARES FITTING METHODS
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BP-EVD: Forward Block-Output Propagation for Efficient Video Denoising
PublicationDenoising videos in real-time is critical in many applications, including robotics and medicine, where varying light conditions, miniaturized sensors, and optics can substantially compromise image quality. This work proposes the first video denoising method based on a deep neural network that achieves state-of-the-art performance on dynamic scenes while running in real-time on VGA video resolution with no frame latency. The backbone...
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Design and Characterization of a Planar Structure Wideband Millimeter-Wave Antenna with Wide Beamwidth for Wearable off-body Communication Applications
PublicationThis letter presents the design of a planar single-layer wideband antenna featuring wide beamwidth has well as high and stable in-band gain. The proposed antenna is a planar monopole fed by a bottom-grounded coplanar waveguide to realize wide beamwidth in both the xz- and yz-planes. Simultaneous optimization of all adjustable antenna parameters, carried out at the full-wave electromagnetic simulation level. The constructive interference...
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High Frequency Conducted Emission in AC Motor Drives Fed By Frequency Converters: Sources and Propagation Paths
PublicationProvides a concise and thorough reference for designing electrical and electronic systems that employ adjustable speed drives Electrical and electronic systems that employ adjustable speed drives are being increasingly used in present-day automation applications. They are considered by many application engineers as one of the most interfering components, especially in a contemporarily faced industrial environment. This book fills...
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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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Textile reinforced concrete members subjected to tension, bending, and in-plane loads: Experimental study and numerical analyses
PublicationTextile reinforced concrete has raised increasing research interest during the last years, mainly due to its potential to be used for freeform shell structures involving complex load situations. Yet, most experimental work has focused on test setups with primarily uniaxial loading. In the current work, such setups are complemented with a novel test setup of deep beams, including in-plane bending and shear. Further, nonlinear finite...
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Simulating propagation of coherent light in random media using the Fredholm type integral equation
PublicationStudying propagation of light in random scattering materials is important for both basic and applied research. Such studies often require usage of numerical method for simulating behavior of light beams in random media. However, if such simulations require consideration of coherence properties of light, they may become a complex numerical problems. There are well established methods for simulating multiple scattering of light (e.g....
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The effect of multiaxial geocomposite reinforcement on fatigue performance and crack propagation delay in double-layered asphalt beams
PublicationThe presented study investigates the effect of a recently developed multiaxial geocomposite made of polypropylene geogrid and non-woven fabric on the delay of crack propagation, based on four-point bending tests of large asphalt concrete beams – both for reinforced and non-reinforced specimens. Several approaches are described in this study, including analysis of stiffness modulus decrease and analysis of crack propagation using...
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Impact of radio wave polarisation on off-body communications in indoor environments
PublicationThis 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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Modeling of light propagation in canine gingiva
PublicationThis study is a preliminary evaluation of the effectivenes of laser-based surgery of maxillary and mandibular bone in dogs. Current methods of gingivial surgery in dogs require the use of general anaesthesia.1, 2 The proposed methods of laser surgery can be performed on conscious dogs, which substantially reduces the associated risks. Two choices of lasers, Nd:YAG and a 930 nm semiconductor lasers were evaluated. The former is...
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System information propagation for composite structures
PublicationWe study in details decoherence process of a spin register, coupled to a spin environment. We use recently developed methods of information transfer study in open quantum systems to analyze information flow between the register and its environment. We show that there are regimes when not only the register decoheres effectively to a classical bit string, but this bit string is redundantly encoded in the environment, making it available...
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Analyses of wave records from the Southern Baltic Sea with the emphases on large wave events
PublicationW pracy przedstawiono wyniki analizy pomiarów szeregów czasowych falowania uzyskanych z boi pomiarowych Waverider, umieszczonych w kilku miejscach linii brzegowej Morza Bałtyckiego. Celem badań było wskazanie okresów i regionów możliwego pojawiania się fal maksymalnych. Rozważano wpływ czasu trwania sztormu i kierunku wiatru na powstawanie pojedynczych oraz grup fal ekstremalnych.
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COMMENTS ON EXISTING ANALYTICAL SOLUTIONS TO THE WAVE-INDUCED CYCLIC RESPONSE OF A POROUS SEABED OF INFINITE THICKNESS
PublicationThis paper deals with the wave-induced cyclic response of a porous seabed (by means of oscillating parameters: pore-fluid pressure, soil displacement components, effective normal stress and shear stress components) due to a surface sinusoidal water-wave propagating over a seabed of infinite thickness. The main existing analytical solutions to the governing problem are critically discussed, pointing out their meaningful errors and...
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Sensorless induction motor drive with voltage inverter and sine-wave filter
PublicationThis paper presents a speed sensorless control system of an induction motor with an output LC filter. It is known that the parameters design of the filter gives sine wave motor supply voltage but complicates control and estimation process. The reason is that the voltage drop and phase shift between filter input and output signals are imposed, and hence the motor voltages and currents differ from the inverter output waveforms. To...
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A sine wave delay estimator
PublicationZaprezentowano nowe rozwiązanie dyskretno-czasowego estymatora ułamkowego opóźnienia sygnału sinusoidalnego, działające w systemie z otwartą pętlą sprzężenia zwrotnego. Proponowane rozwiązanie wykorzystuje koncepcję transformowania za pomocą filtru Hilberta sygnału referencyjnego celem estymacji różnicy fazy tego sygnału względem zaszumionego sygnału odebranego o znormalizowanej (względem okresu próbkowania) częstotliwości - bardzo...
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Automatic music signal mixing system based on one-dimensional Wave-U-Net autoencoders
PublicationThe purpose of this paper is to show a music mixing system that is capable of automatically mixing separate raw recordings with good quality regardless of the music genre. This work recalls selected methods for automatic audio mixing first. Then, a novel deep model based on one-dimensional Wave-U-Net autoencoders is proposed for automatic music mixing. The model is trained on a custom-prepared database. Mixes created using the...
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Automatic audio signal mixing system based on one-dimensional Wave-U-Net autoencoders
PublicationThe purpose of this dissertation is to develop an automatic song mixing system that is capable of automatically mixing a song with good quality in any music genre. This work recalls first the audio signal processing methods used in audio mixing, and it describes selected methods for automatic audio mixing. Then, a novel architecture built based on one-dimensional Wave-U-Net autoencoders is proposed for automatic music mixing. Models...
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Measurement and Analysis of the Radio Wave Polarisation in Off-Body Communications in Indoor Environment
PublicationThe 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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Global Complex Roots and Poles Finding Algorithm Based on Phase Analysis for Propagation and Radiation Problems
PublicationA flexible and effective algorithm for complex roots and poles finding is presented. A wide class of analytic functions can be analyzed, and any arbitrarily shaped search region can be considered. The method is very simple and intuitive. It is based on sampling a function at the nodes of a regular mesh, and on the analysis of the function phase. As a result, a set of candidate regions is created and then the roots/poles are verified...
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Enumerations of Plane Trees with Multiple Edges and Raney Lattice Paths
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Simulation and experiment of radiating slot in a ground-plane of microstrip junction
PublicationW pracy przedstawiono badania numeryczne oraz eksperymentalne szczeliny promieniującej umieszczonej w płaszczyźnie masy złącza mikropaskowego. Złącze mikropaskowe składa się z linii mikropaskowej oraz rozwartego na końcu sęka. Szczelina umieszczona jest równolegle do linii mikropaskowej.
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Numerical analysis of laminated shells under in-plane axial compression
PublicationW pracy analizowana jest stateczność powłoki warstwowej poddanej osiowemu ściskaniu. Badany jest wpływ wariantów uwarstwienia oraz warunków podparcia krawędzi obciążonej na zachowanie konstrukcji. Wyniki numeryczne porównano z eksperymentem.
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Problem of selection of reference plane with deep and wide valleys analysis
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Scale effects in granular bodies during plane strain compression.
PublicationW arykule omówiono efekty skali w materiałach granulowanych spowodowanych wielkością próbek. Obliczenia wykonano stosując MES na bazie prawa hipoplastycznego rozszerzonego o długość charakterystyczną. Porównano różne metody regularyzacji.
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Nonlinear finite element modeling of vibration control of plane rod-type structural members with integrated piezoelectric patches
PublicationThis paper addresses modeling and finite element analysis of the transient large-amplitude vibration response of thin rod-type structures (e.g., plane curved beams, arches, ring shells) and its control by integrated piezoelectric layers. A geometrically nonlinear finite beam element for the analysis of piezolaminated structures is developed that is based on the Bernoulli hypothesis and the assumptions of small strains and finite...
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Crossover from charge density wave stabilized antiferromagnetism to superconductivity in Nd1−xLaxNiC2 compounds
PublicationThe path from the charge density wave antiferromagnet NdNiC2 to the noncentrosymmetric superconductor LaNiC2 is studied by gradual replacement of Nd by La ions. The evolution of physical properties is explored by structural, magnetic, transport, magnetoresistance, and specific heat measurements. With the substitution of La for Nd, the Peierls temperature is gradually suppressed, which falls within the BCS mean-field relation for...
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Instrumented End Notched Flexure - Crack propagation and process zonemonitoring. Part I: Modelling and analysis
PublicationAnalysis of the three-point bending, End Notched Flexure (ENF), test is presented for exploitation with a new experimental methodology using the backface strain monitoring technique. The model consists oftwo Timoshenko beams joined with a two parameter elastic foundation, to evaluate stress and strain fields in both adherends and the adhesive layer, together with the specimen compliance and energyrelease rate. This model is compared...
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Slow-wave resonant structures in branch-line coupler miniaturization: a case study
PublicationA case study of novel slow-wave resonant structures dedicated to efficient microstrip branch-line coupler size reduction has been presented. A compact 3-dB branch-line coupler has been designed to mimic the performance of its conventional counterpart, simultaneously demonstrating a substantial 88% surface area reduction. The vital usefulness of the approach in the process of microstrip line abbreviation has been experimentally...
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The effect of external load on ultrasonic wave attenuation in steel bars under bending stresses
PublicationThe stress state in deformed solids has a significant impact on the attenuation of an ultrasonic wave propagating through the medium. Measuring a signal with certain attenuation characteristics can therefore provide useful diagnostic information about the stress state in the structure. In this work, basic principles behind a novel attenuation-based diagnostic framework are introduced. An experimental study on steel bars under three-point...
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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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Charge density wave, enhanced mobility, and large nonsaturating magnetoresistance across the magnetic states of HoNiC2 and ErNiC2
PublicationWe report on magnetotransport and thermoelectric properties of two ternary carbides HoNiC2 and ErNiC2 hosting both charge density wave and long-range magnetic order. In the charge density wave state, both compounds show relatively large magnetoresistance MR ≈ 150% in HoNiC2 and ≈ 70%in ErNiC2 at a magnetic field of 9 T and temperature as low as 2 K. This positive field-linear magnetoresistance shows no signatures of saturation....
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Simple 60 GHz Switched Beam Antenna for 5G Millimeter-Wave Applications
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Propagation of elastic waves in shell-like structures
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