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Search results for: ships, waves, white noise, damping, density, hull, seas, significant wave heights, testing, wave frequency
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Frequently updated noise threat maps created with use of supercomputing grid
PublicationAn innovative supercomputing grid services devoted to noise threat evaluation were presented. The services described in this paper concern two issues, first is related to the noise mapping, while the second one focuses on assessment of the noise dose and its influence on the human hearing system. The discussed services were developed within the PL-Grid Plus Infrastructure which accumulates Polish academic supercomputer centers....
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The Methods for RTS Noise Identification
PublicationIn the paper authors present two methods, which allows to identify the RTS noise in noise signal of semiconductor devices. The first one was elaborated to identify the RTS noise and also to estimate the number of its levels. The second one can be used to estimate all of the parameters of Gaussian and non-Gaussian components in the noise signal in a frequency domain.
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Circularly Polarized Antenna Array design with the Potential of Gain-Size Trade-off and Omnidirectional Radiation for Millimeter-Wave Small Base Station Applications
PublicationThis paper presents the design and validation of a slot-patch-hybrid circularly polarized antenna array for 28 GHz millimeter (mm) wave (mm-wave) applications. The proposed design has a simple geometry that facilitates the fabrication process, which is otherwise a challenging task due to the sub-mm dimensions of the circuit in the mm-wave band. In the proposed structure, aperture-coupled series slot-fed array is utilized to excite...
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Application of RMS for damage detection by guided elastic waves
PublicationThis paper presents certain results of an experimental study related with a damage detection in structural elements based on deviations in guided elastic wave propagation patterns.
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INFLUENCE OF THE HULL SHAPE ON THE ENERGY DEMAND OF A SMALL INLAND VESSEL WITH HYBRID PROPULSION
PublicationRecently, there has been a significant development of ecological propulsion systems, which is in line with the general trend of environmentally friendly “green shipping”. The main aim is to build a safe, low-energy passenger ship with a highly efficient, emission-free propulsion system. This can be achieved in a variety of ways. The article presents the main problems encountered by designers and constructors already at the stage...
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Ships - inspiring objects in architecture
PublicationSea-going vessels have for centuries fascinated people, not only those who happen to work at sea, but first and foremost, those who have never set foot aboard a ship. The environment in which ships operate is reminiscent of freedom and countless adventures, but also of hard and interesting maritime working life. The famous words of Pompey: “Navigare necesseest, vivere non estnecesse” (sailing is necessary, living – is not necessary),...
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Analysis of noise properties of the optocoupler device
PublicationIn the paper the localization of a source of Random Telegraph Signal noise (RTS noise) in optocoupler devices type CNY 17 were defined. The equivalent noise circuit in low frequency noise for these type optocouplers was proposed.
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Partial characterization of three Korean white lotus cultivars
PublicationThe nutritional and bioactive values of Korean white lotus cultivars (Muan, Chungyang, and Garam)extracted with methanol, water, and acetone solvents were evaluated by the contents of their bioactive compounds and antioxidant activity determined by ABTS, CUPRAC, FRAP, DPPH, and β-carotene-linoleic acid assays. HPLC, fluorometry, and FTIR spectroscopy were employed for evaluation of polyphenols and fatty acids. All lotus cultivar...
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Modelling of high frequency dynamic responses of engineering structures
PublicationModelling of high frequency dynamic responses of engineering structures, especially those related to wave propagation, is a real numerical challenge. Nowadays most of numerical models, used for that purpose, are based on the application of various finite element techniques. However, finite element discrete models may also be considered as possessing certain periodic structures, which may manifest themselves in particular scenarios....
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Measurements of flicker noise in supercapacitor cells
PublicationFlicker noise (1/f-like noise) is often used to assess the quality of various materials and devices. This phenomenon has been observed in different electrochemical devices or reactions (e.g., smart windows, pitting corrosion events). In our exploratory studies we consider how to measure and utilize 1/f noise for the quality assessment of supercapacitors. This task requires special attention because of enormous capacitance of the...
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Viscous versus electromagnetic damping – amplification in a neighbourhood of a mechanism singular position
PublicationIn the paper, damping of vibrations are considered and compared in a mechanical and in a electromechanical system. In the system, a continuous beam is considered as the main vibrating element. The compared dissipations methods are based on: viscous dampers and DC generators. To increase the possible damping effectiveness, velocity amplification is proposed, i.e., a mechanism is introduced between the beam and the damping element....
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Audio codec employing frequency-derived tonality measure
PublicationA transform codec employing efficient algorithm for detection of spectral tonal components is presented. The tonality measure used in MPEG psychoacoustic model is replaced with the method providing adequate tonality estimates even if the tonal components are deeply frequency modulated. The reliability of hearing threshold estimated using psychoacoustic model with standardized tonality measure and the proposed one is investigated...
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Numerical Estimation of Hull Hydrodynamic Derivatives in Ship Maneuvering Prediction
PublicationPrediction of the maneuvering characteristics of the ship at the design stage can be done by means of model tests, computational simulations or a combination of both. The model tests can be realized as direct simulation of the standard maneuvers with the free running model, which gives the most accurate results, but is also the least affordable as it requires very large tank or natural lake, as well as complex equipment of the...
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Elastic wave propagation in frame structure in the context of structural health monitoring
PublicationPraca dotyczy propagacji fal sprężystych r konstrukcji ramowej w ośrodku typu belka Timoszenki. 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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Modeling of the finite amplitude plane wave propagation in non-dissipative medium
PublicationPraca prezentuje wyniki analizy teoretycznej zagadnienia propagacji fali płaskiej o skończonej amplitudzie w ośrodku wodnym bez dyssypacji. Przedstawiono model matematyczny i przykładowe wyniki obliczeń numerycznych. Model matematyczny zbudowano w oparciu o jednowymiarowe równania mechaniki płynów. Do rozwiązania zagadnienia zastosowano metodę różnic skończonych. Analizowano zmiany ciśnienia i zmiany widma. Badano zbieżność i dokładność...
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Extreme bottom velocities induced by wind wave and currents in the Gulf of Gdańsk
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MEDIUM-TERM WAVE AND CURRENT MODELLING FOR A MESOTIDAL WADDEN SEA COAST
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Wind wave climate of west Spitsbergen: seasonal variability and extreme events
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Wave-induced bedload transport – a study of the southern Baltic coastal zone
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The expansion wave of an invasive predator leaves declining waterbird populations behind
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On some properties of 2d spectral finite elements in problems of wave propagation
PublicationW 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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Design solution and selected research results of the sea-wave energy converter
PublicationW 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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Lamb Wave Based Structural Damage Detection Using Stationarity Tests
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Rectangular microstrip resonator illumi-nated by normal-incident plane wave
PublicationW 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
PublicationRozdział 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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Radiation phenomena from metamaterial cylinders at oblique plane wave incidence.
PublicationW pracy przedstawiono wpływ ujemnej przenikalności elektrycznej i magnetycznej rezonatorów cylindrycznych umieszczonych w wolnej przestrzeni na parametry rozproszenia. Wykorzystano zmodyfikowaną procedurę iteracyjną i metodę dopasowania rodzajów w celu badania fali rozproszonej od układu cylindrów przy ukośnym padaniu fali płaskiej.
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Identification of discontinuites in composite rods and beams based on Lamb wave propagation
PublicationW pracy omówiono metodę identyfikacji typu nieciągłości w belkach i prętach kompozytowych, oparta o analizę zmain w propagacji fali Lamba.
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Experimental an numerical investigation of wave propagation in composite beam with an additional mass
PublicationW pracy przedstawiono wyniki badań eksperymentalnych i symulacji numerycznych ilustrujace wpływ dodatkowej masy na propagacje fali Lamba w belce kompozytowej.
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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
PublicationPrzedyskutowano 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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Wave propagation modelling in 1D structures using spectral finite elements
PublicationW artykule omówiono modele propagacji fal wzdłużnych i poprzecznych w prętach oparte na dwóch sformułowaniach (w dziedzinie częstości i w dziedzinie czasu) metody elemntów spektralnych. Porównano otrzymane wyniki z wynikami eksperymentu.
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Electromagnetic wave scattering by a set of axially symmetric omega-medium cylinder
PublicationZaprezentowano 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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Comparison of selected parametric methods for prediction of inland waterways ship hull resistance in towing tank test
PublicationIn the paper selected approximate methods for calculation of inland waterways ship resistance and their verification by towing tests, compared on the example of a small urban ferry, are presented. The test results are made for both the bare hull and the hull with appendages (skeg, azimuthal propeller). Significant differences between results of the theoretical methods and experimental ones, especially in the case of the model with...
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A fast time-frequency multi-window analysis using a tuning directional kernel
PublicationIn this paper, a novel approach for time-frequency analysis and detection, based on the chirplet transform and dedicated to non-stationary as well as multi-component signals, is presented. Its main purpose is the estimation of spectral energy, instantaneous frequency (IF), spectral delay (SD), and chirp rate (CR) with a high time-frequency resolution (separation ability) achieved by adaptive fitting of the transform kernel. We...
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Tire camber angle influence on tire-pavement noise
PublicationTaking into account tire-pavement noise and tires classification with respect to noise emission special measurement methods are usually used. When two of them are applied (the Laboratory Drum Method (DR) and the Close-Proximity Method (CPX)) the investigator has to be sure that the position of the tire is correct. The authors of this paper thought about tire position as tire (wheel) alignment in particular tire camber angle. They...
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A new modelling arrangement for testing of Catenary Anchoring Leg Mooring (CALM) system behaviour in waves
PublicationW artykule przedstawiono układ modelowy pławy cumowniczo-przeładunkoweji łańcuchów kotwicznych możliwy do realizacji w wydłużonych basenach falowych służących na co dzień do badania właściwości morskich statków. System łańcuchów kotwicznych sprowadzono do płaszczyzn równoległych do osi basenu i połączono z pławą cienkimi linkami stalowymi przechodzącymi przez bloczki kierunkujące. Opisywany układ pozwolił na przeprowadzenie badań...
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Chemical identification of rubber fender sample and hardness and density measurements
PublicationScope of testing: Chemical identification of rubber fender sample and hardness and density measurements. - Raport z badań zleconych - Numer umowy: 031178
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Massively parallel linear-scaling Hartree–Fock exchange and hybrid exchange–correlation functionals with plane wave basis set accuracy
PublicationWe extend our linear-scaling approach for the calculation of Hartree–Fock exchange energy using localized in situ optimized orbitals [Dziedzic et al., J. Chem. Phys. 139, 214103 (2013)] to leverage massive parallelism. Our approach has been implemented in the ONETEP (Order-N Electronic Total Energy Package) density functional theory framework, which employs a basis of non-orthogonal generalized Wannier functions (NGWFs) to achieve...
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Comparing noise levels and audiometric testing results employing it based diagnostic systems.
PublicationW referacie przedstawiono Internetowy system przeznaczony do przeprowadzania przesiewowych testów słuchu. Zaprezentowano również system informacyjny przeznaczony do monitorowania hałasu środowiskowego. Obie Internetowe aplikacje mogą być pomocne w zmniejszaniu częstości występowania chorób słuchu powodowanych przez hałas środowiskowy i przemysłowy. Porównano wyniki testów audiometrycznych z pomiarami hałasu na podstawie zawartości...
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Noise measurements on low noise pavements - problems with inhomogeneity of wearing course
PublicationDuring the last several years, when performing numerous CPX noise measurements on low noise pavements,significant inhomogeneity of the wearing course was observed in numerous cases. Similar problems were almost not existing regarding to the dense pavements.In general three main reasons of inhomogeneity can be defined. The first one are imperfections in technology of production of a asphalt mix or/and errors made already during...
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Phytoremediation of heavy metals by white cabbage
PublicationPhytoremediation is regarded as the cheapest and environmentally most friendly technology for cleaning up soil. The most widespread and most profitable technique is phytoextraction, used mainly for removing heavy metals and radioactive elements from thesoil. Over 400 plant species have been identified as natural metal hyperaccumulators representing about 0.2 % of all angiosperms. Unfortunately, most of these plants are characterised...
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Reduction of Influence of the High-Frequency Noise on the Results of Surface Topography Measurements
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Measurement of noise parameter set in the low frequency range: requirements and instrumentation.
PublicationOpisano dwa podstawowe szumowe modele metrologiczne czwórnika: ze źródłami szumów odniesionymi do wejścia i ze zwarciowymi prądami szumów. Parametry szumowe opisujące modele zawierające korelację pomiędzy prądami i/lub napięciami są mierzone przy zastosowaniu metod bezpośrednich i pośrednich. Przedstawiono kilka technik redukcji szumów własnych systemu pomiarowego. Szerzej zaprezentowano dwukanałowy system do pomiaru szumów z komputerowym...
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Low frequency noise and DLTS as silicon solar cell characterization tools
PublicationPraca zawiera wyniki pomiarów DLTS próbek o powierzchni 1 mm2 krzemowych baterii słonecznych wykazujących znaczne niejednorodności wykryte za pomocą metody LBIV (Light Beam Induced Voltage). Wyniki pomiarów charakterystyk stałoprądowych oraz szumowych tych próbek zostały także przedstawione.
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Noise sources in Raman spectroscopy of biological objects
PublicationWe present an overview of noise sources deteriorating the quality of the recorded biological Raman spectra and the ability to determine the specimen composition. The acquired Raman spectra exhibit intense additive noise components or drifts because of low intensity of the scattered light. Therefore we have to apply expensive or bulky measurement setups to limit their inherent noise or to apply additional signal processing to reduce...
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Use of white cabbage for phytoremediation processes
PublicationQuite a large biomass and the lack of difficulties after harvesting are advantages described for different types of cabbage. Our study reveals the usefulness of the white cabbage for the purification of the soil from zinc and cadmium by phytoextraction. Two cabbage (Brasica oleracea subsp. capitata f. alba) cultivars: early cv. Ditmarska Najwcześniejsza (DN), late cv. Kamienna Głowa (KG) were used.
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Detection and Imaging of Debonding in Adhesive Joints of Concrete Beams Strengthened with Steel Plates Using Guided Waves and Weighted Root Mean Square
PublicationStrengthening of engineering structures is an important issue, especially for elements subjected to variable loads. In the case of concrete beams or slabs, one of the most popular approaches assumes mounting an external reinforcement in the form of steel or composite elements by structural adhesives. A significant disadvantage of adhesive joints is the lack of access to the adhesive film for visual condition assessment, thus, there...
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Analysis of the Environmental Impact of the Hull Construction of a Small Vessel Based on LCA
PublicationIn recent years, issues related to the impact of human activity on the natural environment have become pressing, and the challenge of global warming necessitates immediate action. To support environmental protection efforts, it has become imperative to adopt a broader perspective when evaluating various products and systems. A valuable tool for such assessments is a life cycle assessment (LCA), which enables a comprehensive analysis...
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