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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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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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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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SPECTRAL RESPONSE OF STATIONARY JACK-UP PLATFORMS LOADED BY SEA WAVES AND WIND USING PERTURBATION METHOD
PublicationThe paper addresses non-linear vibrations of offshore jack-up drilling platforms loaded by sea waves and wind in their stationary condition using the perturbation method. Non-linearity of dynamic equations of motion for fixed offshore platforms yields from two factors. The first is load excitation generating non-linear velocity coupling in a dynamic system. This coupling is inherent in the modified Morison equation, involving the...
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Flicker Noise in Resistive Gas Sensors—Measurement Setups and Applications for Enhanced Gas Sensing
PublicationWe discuss the implementation challenges of gas sensing systems based on low-frequency noise measurements on chemoresistive sensors. Resistance fluctuations in various gas sensing materials, in a frequency range typically up to a few kHz, can enhance gas sensing by considering its intensity and the slope of power spectral density. The issues of low-frequency noise measurements in resistive gas sensors, specifically in two-dimensional...
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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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TRAVELLING WAVES FOR LOW–GRADE GLIOMA GROWTH AND RESPONSE TO A CHEMOTHERAPY MODEL
PublicationLow-grade gliomas (LGGs) are primary brain tumours which evolve very slowly in time, but inevitably cause patient death. In this paper, we consider a PDE version of the previously proposed ODE model that describes the changes in the densities of functionally alive LGGs cells and cells that are irreversibly damaged by chemotherapy treatment. Besides the basic mathematical properties of the model, we study the possibility of the...
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Review of Selected Methods for Prediction of Added Resistance in Following Waves
PublicationThe added resistance in waves is a mean value of non-linear, second order reaction of a ship to incoming waves. In the beginning of the 20th century, the experimental methods for investigation of ship hydrodynamics at model scale were developed. They allowed the evaluation of added resistance by measurements in irregular waves (directly) or by measurements in regular waves (in-direct method). The main goal was to find more precise...
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Diagnostics of zno varistors by means of nondestructive testing
PublicationStandard industrial testing of high-voltage varistors for surge arresters demands application of high voltages and intensive currents. Nondestructive methods for varistor quality and endurance evaluation have been proposed and described. They rely on the application of resonant ultrasound spectroscopy, electro-ultrasonic spectroscopy, noise measurement and nonlinearity testing at voltages lower than continuous operating range....
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Single-dopant organic white electrophosphorescent diodes with very high efficiency and its reduced current density roll-off
PublicationW pracy opisano konstrukcję wysokowydajnej diody elektrofosforescencyjnej zawierającej domieszkę organicznego kompleksu platyny PtL2Cl (L oznacza organiczny ligand). Dioda emituje światło białe które pochodzi od ekscymerów świecących w czerwieni i wzbudzonych monomerów świecących w części niebieskiej widma. Kwantowa wydajność świecenia diody wynosi ok. 15% i słabo maleje ze wzrostem gęstości płynącego prądu elektrycznego.
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Noise emitted by SKM Trains in Gdansk
PublicationHigh intensity traffic of SKM trains in Gdansk carries a significant level of noise emission. SKM line runs through the central part of the city and therefore in the vicinity of residential areas and recreational facilities. This research was planned and performed to find out what was the real noise emission of SKM trains and to determine whether the measurement noise values are within allowed limits. Individual acoustic events...
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The current amplifier in low frequency noise measurements; Absolute calibration and rigorous 1/f noise extraction for MOSFET´s
PublicationPrzedstawiono budowę wzmacniacza prądowego i sposób obliczania szumów wyjściowych przy dołączonym do wejścia rezystorze wzorcowym. Przedstawiono wyniki eksperymentów potwierdzających prawidłowość przyjętego sposobu postępowania. Zaproponowano metodę wyznaczania składowej 1/f szumów drenu tranzystora MOSFET.
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Changes in conditions of acoustic wave propagation in the Gdansk deep as an effect of climate changes in the Baltic Sea region
PublicationThe article presents the results from a research project investigating acoustic climate changes in the Gdansk Deep based on data extending from 1902 to 2019. This part of the southern Gotland Basin, is rarely discussed in the scientific literature. The speed of sound in the seawater is a function of temperature, salinity, and depth. In such shallow sea as Baltic Sea, the impact of depth is not substantial. The other two factors...
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Silence/noise detection for speech and music signals
PublicationThis paper introduces a novel off-line algorithm for silence/noise detection in noisy signals. The main concept of the proposed algorithm is to provide noise patterns for further signals processing i.e. noise reduction for speech enhancement. The algorithm is based on frequency domain characteristics of signals. The examples of different types of noisy signals are presented.
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Characterization of Corrosion-Induced Fracture in Reinforced Concrete Beams Using Electrical Potential, Ultrasound and Low-Frequency Vibration
PublicationThe paper deals with the non-destructive experimental testing of the reinforced concrete beams under progressive corrosion. A series of experiments using electrical potential, ultrasound and low-frequency vibrations techniques are reported. Electrical potential and natural frequencies were used to characterise and monitor the corrosion process at its initial state. The P-wave velocity measurements were proved to be effective in...
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Changes in conditions of acoustic wave propagation in the Gdansk deep as an effect of climate changes in the Baltic Sea region
PublicationThe article presents the results from a research project investigating acoustic climate changes in the Gdansk Deepbased on data extending from 1902 to 2019. This part of the southern Gotland Basin, is rarely discussed in thescientific literature.The speed of sound in the seawater is a function of temperature, salinity, and depth. In such shallow sea asBaltic Sea, the impact of depth is not substantial....
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Influence of pulse waves on the transmission of near-infrared radiation in outer-head tissue layers.
PublicationIn this study, we investigate the effect of pulse waves on the transmission of near-infrared radiation in the outer tissue layers of the human head. This effect is important in using optical radiation to monitor brain conditions based on measuring the transmission changes in the near-infrared radiation between the source and the detector, placed on the surface of the scalp. This is because the signal related to the changes in the...
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METHODS OF TEACHING NOISE PROTECTION AT ENVIRONMENTAL ENGINEERING
PublicationNoise strongly influences both our health and behavior in everyday life and as employees or employers. The lost of hearing and other effects of noise on humans result not only in a significant decrease in the quality of life or work efficiency but have also have economic consequences. As noise can be preventable in part by the Environmental Engineers, but it is necessary to introduce them noise issues during their education process....
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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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Impact of sea wave stochastic characteristics on ship propulsion control system design.
PublicationWybrano 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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60 GHz Microstrip Van Atta Arrays for Millimeter Wave Identification and Localization
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Simple 60 GHz Switched Beam Antenna for 5G Millimeter-Wave Applications
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Response of the local pair superconductor to the static vector potential at finite wave length
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Design of quarter-wave compact impedance transformers using coupled transmission lines
PublicationPrzedstawiono 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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Pulse wave velocity is associated with early clinical outcome after ischemic stroke
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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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Piecewise continuous distribution function method in the theory of wave disturbances of inhomogeneous gas
PublicationUkład 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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Damage detection of a T-shaped panel by wave propagation analysis in the plane stress
PublicationW pracy zaprezentowano podejście obliczeniowe do analizy propagacji fal w płaskim stanie naprężenia. Problem brzegowo-początkowy podlega przestrzennej aproksymacji z użyciem wielowęzłowych, izoparametrycznych, czworobocznych elementów klasy C0. Macierze elementowe są całkowane numerycznie za pomocą kwadratury Gauss-Legendre-Lobatto. Aproksymację w dziedzinie czasu wykonano za pomocą algorytmu Newmarka. Symulacje numeryczne przeprowadzono...
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Assessment of flexural beam behaviour theories used for dynamics and wave propagation problems
PublicationW pracy przedstawiono i porównano teorie belek zginanych począwszych od teorii elementarnych, aż do teorii wyższych rzędów. Przedstawiono krzywe dyspersi dla poszczególnych teorii i na ich podstawione oszacowano zakres stosowalności danej teorii.
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Guided wave propagation in structures. Modelling, experimental studies and application to damage detection
PublicationCelem niniejszej pracy są eksperymentalne i numeryczne analizy propagacji prowadzonych fal sprężystych w stalowych konstrukcjach prętowych, belkowych, ramowych, tarczowych i płytowych. W szczególności praca poświęcona jest: (a) modelowaniu propagacji fal z uwzględnieniem zjawiska dyspersji; (b) budowie modeli obliczeniowych w formalizmie metody elementów spektralnych; (c) eksperymentalnej weryfikacji zaproponowanych modeli; (d)...
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Shock wave - boundary layer interaction control by air-jet streamwise vortices
PublicationW 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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Modelling of wave propagation in spatial frame elements - numerical simulations and experimental works
PublicationW 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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Acousto-optic interaction of a Gaussian laser beam with an ultrasonic wave of cylindrical symmetry
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Experimental and numerical studies of guided wave damage detection in bars with structural discontinuities
PublicationPraca dotyczy analizy propagacji fal podłużnych i poprzecznych w elementach prętowych z nieciągłościami strukturalnymi. Symulacje numeryczne przeprowadzone przy zastosowaniu metody elementów spektralnych zostały porównane z wynikami badań eksperymentalnych dla pręta w stanie nienaruszonym oraz dla prętów z rysą, spawem oraz dodatkową masą.
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The spectral finite element model for analysis of flexural–shear coupled wave propagation
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Cointegration approach for temperature effect compensation in Lamb-wave-based damage detection
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Internal imaging of concrete fracture based on elastic waves and ultrasound computed tomography
PublicationThe condition assessment of concrete structures belongs to the greatest challenges of non-destructive testing. Monitoring the fracture process of concrete and detecting cracks at the earliest possible stage is a vital aspect to ensure the safety of civil engineering objects. The use of ultrasound tomography enables imaging the internal structure of a tested element. This study aims at the visualization of fracture damage in concrete...
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Reduction of road traffic noise by source measures — present and future strategies
PublicationThe current trend worldwide is less focused on reducing road traffic noise. This is in strong contrast to the severe impact of traffic noise to the general health and quality of life. A more holistic and combined strategy is needed. Current international rules and regulations regarding vehicles and tyres are not sufficient to reduce traffic noise levels in an effective way. Calculations show that these regulations will only yield...
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Extending the Frequency Limit of Microstrip-Coupled CSRR Using Asymmetry
PublicationAbstract— This article explains the frequency limitation in designing microstrip circuits based on a complementary split-ring resonator (CSRR) and reports a novel technique for increasing its operating frequency, which makes the CSRR suitable for high-frequency applications. This study helps in synthesizing the dimensions of symmetric CSRR (SCSRR) and asymmetric CSRR (ACSRR) circuits, which shows the applicability of the proposed...
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JOURNAL OF ELECTROMAGNETIC WAVES AND APPLICATIONS
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Identification of inherent noise components of semiconductor devices on an example of optocouplers
PublicationIn the paper, a method of estimation of parameters of Gaussian and non-Gaussian components in the noise signal of semiconductor devices in a frequency domain is proposed. The method is based on composing estimators of two spectra, corresponding to noise (Gaussian component) and two-level RTS noise (non-Gaussian component). The proposed method can be applied for precise evaluation of the corner RTS frequency fRTS in the noise...
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The statistic properties of rms voltage and frequency in the ship's electrical power system
Open Research DataThe dataset is a part of the research results on the quality of supply voltage on bus bars of the main switchboard of the ship's electrical power system in different states of ship exploitation. The attached dataset contains the results of a statistical analysis of rms voltage and frequency in the ship's electrical power system. The following statistical...
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1/f noise as a diagnostic tool for non-destructive testing of silicon solar cells
PublicationPrzeprowadzono badania eksperymentalne charakterystyk statycznych i szumowych krzemowych ogniw słonecznych. Wyniki wykazują możliwość wykorzystania szumu 1/f jako narzędzia diagnostycznego w testach nieniszczacych tych przyrzadów.
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Effect of package type on selected parameters of nutritional quality of chill-stored white sauerkraut
PublicationBrassica vegetables, including white cabbage, both fresh and sour (Brassica oleracea L. var. capitata L.), contain a lot of valuable metabolites which are effective in chemoprevention of cancer as documented by numerous studies. This work investigates the effect of different packaging types; low density polyethylene (PE-LD) and metalized polyethylene terephthalate (PET met/PE) with polyethylene bags on selected quality parameters in...
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Design and Optimization of Metamaterial-based Highly-isolated MIMO Antenna with High Gain and Beam Tilting Ability for 5G Millimeter Wave Applications
PublicationThis paper presents a wideband multiple-input multiple-output (MIMO) antenna with high gain and isolation, as well as beam tilting capability, for 5G millimeter wave (MMW) applications. A single bow-tie antenna fed by a substrate-integrated waveguide (SIW) is proposed to cover the 28 GHz band (26.5–29.5 GHz) with a maximum gain of 6.35 dB. To enhance the gain, H-shaped metamaterial (MM)-based components are incorporated into the...
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Fabrication and Characterization of Green Polyurethane Foams with Enhanced Vibration Damping Capability
PublicationOver the past decades, there has been an intensive development of the technologies and innovations aimed at increasing the quality of life. This development largely concerns the comfort of use of everyday products that, among others, are products of the automotive, construction, or furniture industries. Considering the increase in the comfort of using products such as cars, houses, and flats, one of the comfort features of their...
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Decoding of the FSK signal with noise and distortion with the use of coefficients of the time-frequency transform.
PublicationStreszczenie: Przeanalizowano sygnał z modulacją FSK wykorzystując metodę transformacji czasowo-częstotliwościowej różniące się sposobem podziału płaszczyzny TF na atomy: krótko-okresowej transformacji Fouriera, transformacji falkowej i transformacji pakietami falkowymi. Transformacja falkowa zapewnia dobrą lokalizację czasową zakłóceń o wielkiej częstotliwości, podczas gdy transformacja pakietami falkowymi zapewnia dobrą lokalizację...
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Low Frequency Noise Measurement of Reverse Polarized Silicon Carbide Schottky Diodes
PublicationW artykule przedstawiono wyniki pomiaró szumów cz. wstecznie spolaryzowanych diod Schottky'ego.
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APPLICATION OF QUANTITATIVE RISK ASSESSMENT TO SHIPS IN EMERGENCY CONDITIONS
PublicationThe paper is devoted to safety of ships in emergency conditions. The currently valid prescriptive method of safety assessment of ships in damage conditions is included in the SOLAS 2009 Part B-2 Ch.II-1 regulations. It is devoted to the design stage and difficult to apply in operation. A possible alternative described in this paper is a method based on assessment of performance of ships and risk assessment. Type of risk evaluation...