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Wyświetlanie 1-15 z 66
Tytuł:
Investigation of propagation of acoustic wave generated by a moving ship
Autorzy:
Gloza, I.
Domagalski, J.
Powiązania:
https://bibliotekanauki.pl/articles/331561.pdf
Data publikacji:
2003
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
acoustic wave
moving ship
Opis:
A moving ship is a source of acoustic perturbations resulting from her complex hull being a surface of irregular shape and from a rotational source - the propellers. The sources generate acoustic waves in wide frequency band. In case of a shallow sea the prapagation of the acoustic waves for varying source-detector distances and different frequencies are described applying the modes and ray theory.
Źródło:
Hydroacoustics; 2003, 6; 183-188
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Design, Manufacture and Characterization of an Acoustic Barrier Made of Multi-Phenomena Cylindrical Scatterers Arranged in a Fractal-Based Geometry
Autorzy:
Casteneira-Ibanez, S.
Rubio, C.
Romero-Garcia, V.
Sanchez-Perez, J. V.
Garcia-Raffi, L. M.
Powiązania:
https://bibliotekanauki.pl/articles/176662.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
acoustic arrays
acoustic attenuation
acoustic wave absorption
acoustic wave scattering
phononic crystals
acoustic barrier
physical effect of sound
Opis:
In this work we present the design and the manufacturing processes, as well as the acoustics standard- ization tests, of an acoustic barrier formed by a set of multi-phenomena cylindrical scatterers. Periodic arrangements of acoustic scatterers embedded in a fluid medium with different physical properties are usually called Sonic Crystals. The multiple scattering of waves inside these structures leads to attenuation bands related to the periodicity of the structure by means of Bragg scattering. In order to design the acoustic barrier, two strategies have been used: First, the arrangement of scatterers is based on fractal geometries to maximize the Bragg scattering; second, multi-phenomena scatterers with several noise con- trol mechanisms, as resonances or absorption, are designed and used to construct the periodic array. The acoustic barrier reported in this work provides a high technological solution in the field of noise control.
Źródło:
Archives of Acoustics; 2012, 37, 4; 455-462
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical modeling of transient acoustic field using finite element method
Autorzy:
Koudela, L.
Jansa, J.
Karban, P.
Powiązania:
https://bibliotekanauki.pl/articles/377945.pdf
Data publikacji:
2013
Wydawca:
Politechnika Poznańska. Wydawnictwo Politechniki Poznańskiej
Tematy:
acoustic field
finite element method
acoustic wave
Opis:
Numerical solution of acoustic wave equation in the time domain is performed. The appropriate mathematical model is described by the partial differential wave equation supplemented with appropriate boundary conditions. The goal is to obtain the time evolution of the distribution of acoustic pressure, which can serve as the basis for the solution of various subsequent problems. The paper discusses the results of the numerical analysis of a semicircular acoustic diffuser in a free field, realized by a fully adaptive higher-order finite element method implemented in our own codes Agros2D and Hermes. The results are compared with the data obtained by the commercial code Comsol Multiphysics.
Źródło:
Poznan University of Technology Academic Journals. Electrical Engineering; 2013, 73; 155-160
1897-0737
Pojawia się w:
Poznan University of Technology Academic Journals. Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Determination of the B/A of biological media by measuring and modeling nonlinear distortion of pulsed acousticwave in two-layermedia
Autorzy:
Kujawska, T.
Powiązania:
https://bibliotekanauki.pl/articles/331553.pdf
Data publikacji:
2008
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
acoustic wave
B/A
biological media
Opis:
The acoustic nonlinearity parameter, B/A, is a fundamental material constant characterizing nonlinear properties of biological media. Knowledge of the B/A of biological fluids or soft tissues through which pulsed acoustic waves generated from clinically relevant probes are propagating is necessary whenever high intensity pressure fields are produced. The numerical model recently developed in our lab, capable of predicting the pulsed sound fields generated from axisymmetric sources in nonlinear attenuating media, was a powerful instrument for investigating nonlinear acoustic fields produced from circular plane or focused sources in attenuating media in dependence on boundary condition parameters. Quantitative analysis of the obtained results enabled developing the alternative method for determination of the B/A parameter of biological media. First, the method involves measuring in the near field of a piezoelectric transducer the nonlinear waveform distortion of the pulsed acoustic wave propagating through the two-layer system of media: water-tested material. Then, the method involves numerical modeling, in frequency domain and under experimental boundary conditions, the nonlinear waveform distortion of the propagating wave by using the Time-Averaged Wave Envelope (TAWE) approach [1]. The obtained numerical simulation results were fitted to the experimental data by adjusting the B/A parameter of the tested material. The determined values of the B/A for standard media considered (corn oil, glycerol, pig blood, homogenized pig liver), whose density, sound velocity and attenuation law have been preliminary determined experimentally, are in a good agreement with those published. The proposed method ensure the decimal degree of accuracy, is relatively simple to use and requires small volume of tested materials that is important because of difficulty of their availability.
Źródło:
Hydroacoustics; 2008, 11; 149-158
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical Method for Modeling of Acoustic Waves Propagation
Autorzy:
Dykas, S.
Wróblewski, W.
Rulik, S.
Chmielniak, T.
Powiązania:
https://bibliotekanauki.pl/articles/177994.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
acoustic wave
fluctuations
aerodynamic noise
Euler equations
Opis:
In this paper, numerical results of modeling of acoustic waves propagation are presented. For calculation of the acoustic fluctuations, a solution of the full non-linear Euler equation is used. The Euler equations are solved with the use of a numerical scheme of third-order accuracy in space and time. The paper shows a validation process of the described method. This method is suitable also for an aerodynamic noise assessment on the basis of unsteady mean flow field data obtained from a CFD calculations. In such case this method is called a hybrid CFD/CAA method. The proposed method is numerically decoupled with CFD solution, therefore the information about the mean unsteady flow field can be obtained using an arbitrary CFD method (solver). The accuracy of the acoustic field assessment depends on the quality of the CFD solutions. This decomposition reduces considerably the computational cost in comparison with direct noise calculations. The presented Euler acoustic postprocessor (EAP) has been used for modeling of the acoustic waves propagation in a cavity and in the flow field around a cylinder and an aerodynamic profile.
Źródło:
Archives of Acoustics; 2010, 35, 1; 35-48
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Technique for Measuring Spatial Distribution of the Surface Acoustic Wave Velocity in Metals
Autorzy:
Mokryy, O.
Tsyrulnyk, O.
Powiązania:
https://bibliotekanauki.pl/articles/177231.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
ultrasound
surface acoustic waves
acoustic wave velocity
spatial resolution
Opis:
In this paper a possibility of determining a local velocity of the surface acoustic Rayleigh waves using a transducer, with the rigidly connected emitting and receiving parts, is considered. A problem on spatial resolution of such a transducer for investigation of inhomogeneous specimens is also examined. A high spatial resolution can be obtained due to the transducer displacement by a value less than the distance between the emitting and receiving parts. It is shown that in this case it is not necessary to measure the transducer displacement with a high accuracy for precise determination of the velocity. Such an effect is obtained through measuring the velocity of surface waves in one local region of the specimen with respect to the other. The criterion for optimal spatial resolution selection during spatially inhomogeneous specimens study is also proposed. The proposed criterion use is illustrated on the example of the determination of spatial distribution of the surface acoustic velocity in a steel specimen subjected to inhomogeneous plastic deformation.
Źródło:
Archives of Acoustics; 2016, 41, 4; 741-746
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Models and methods of processing of information on loads of acoustic signals in technical diagnostic system
Modele i metody przetwarzania informacji dla sygnałów akustycznych w systemach diagnostyki technicznej
Autorzy:
Sharko, A.
Powiązania:
https://bibliotekanauki.pl/articles/408137.pdf
Data publikacji:
2018
Wydawca:
Politechnika Lubelska. Wydawnictwo Politechniki Lubelskiej
Tematy:
acoustic wave modeling
discretization
modelowanie fali akustycznej
dyskretyzacja
Opis:
The paper presents one-dimensional discrete-continuous model of power spectrum estimation of the acoustic emission signal, that allows filtering the oscillating components of the acoustic emission signals. The mathematical formalism describing the environment was discussed, initiating the signals of acoustic emission. The problem of spectral analysis and synthesis of acoustic emission signals was solved with the help of Fourier transform. The dependence of acoustic vibrations spectra on the size of the medium parameters and microstructure has been discussed, as well.
W artykule przedstawiony jednowymiarowy, dyskretno-ciągły model wyznaczania energii widma sygnału akustycznego, który pozwala na filtrowanie jego składowych widmowych. Rozwiązano formalizm matematyczny opisujący środowisko, inicjujący emisję sygnałów akustycznych, w którym problem analizy widmowej i syntezy emisji sygnałów akustycznych został rozwiązany z pomocą transformaty Fouriera. Przedyskutowano także wpływ widma wibracji akustycznych na wielkość parametrów ośrodka i jego mikrostrukturę.
Źródło:
Informatyka, Automatyka, Pomiary w Gospodarce i Ochronie Środowiska; 2018, 8, 3; 15-18
2083-0157
2391-6761
Pojawia się w:
Informatyka, Automatyka, Pomiary w Gospodarce i Ochronie Środowiska
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Application of the Theory of Synthesis of a Delay Line with a Surface Acoustic Wave for a Single-Mode Oscillator of Electric Signals in Some Sensors of Non-Electrical Quantities
Autorzy:
Šimko, M.
Gutten, M.
Chupáč, M.
Korenčiak, D.
Powiązania:
https://bibliotekanauki.pl/articles/221409.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
delay line
oscillator
surface acoustic wave
interdigital transducers
Opis:
The paper deals with the issue of constructing delay lines on the basis of surface acoustic waves and their application to single-mode oscillators. As a result of a theoretical analysis concrete delay lines are proposed. In the contribution, there is presented a theory of designing a symmetrical mismatched and matched delay line for a single-mode oscillator of electrical signals on the basis of which there were designed and fabricated acoustic-electronic components for sensors of non-electrical quantities. From the experimental results it can be stated that all of six designed and fabricated delay lines can be effectively used in the construction of single-mode oscillators.
Źródło:
Metrology and Measurement Systems; 2017, 24, 3; 563-576
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Transmission of Ultrasonic Waves Via Optical Silica Glass Fiber Doped by 7.5% of TiO2 with the Use of Power Sandwich Transducer
Autorzy:
Muc, S.
Gudra, T.
Powiązania:
https://bibliotekanauki.pl/articles/177364.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
ultrasounds
transmission of acoustic wave in an optical waveguide
Opis:
The possibility of acoustic wave propagation in optical waveguides creates new prospects for simultaneous transmission of laser beams and ultrasonic waves. Combined laser-ultrasonic technology could be useful in e.g. surgical treatment. The article presents the results of experimental studies of transmission of ultrasonic wave in optical fibres, the core of which is doped by 7.5% of TiO2, using a sandwichtype transducer. It also presents amplitude characteristics of an ultrasonic signal propagated in the optical fibre. Authors studied the effect which the length of the fibre has on the achieved output signal amplitudes. They presented the relation of the output signal amplitude from a capacitive sensor to the power applied to the sandwich-type transducer. The obtained results were compared with the results produced when using an optical fibre with a core doped by 3% of GeO2, in order to select optical fibre suitable for simultaneous transmission of ultrasonic waves and laser rays.
Źródło:
Archives of Acoustics; 2011, 36, 1; 141-150
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Surface Acoustic Wave Interaction with a Mixture of Oxygen and Nitrogen
Autorzy:
Pasternak, Mateusz
Jasek, Krzysztof
Grabka, Michał
Borowski, Tomasz
Powiązania:
https://bibliotekanauki.pl/articles/176628.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
surface acoustic wave sensors
oxygen detection
leaky Rayleigh waves
Opis:
Parameters of surface acoustic waves (SAW) are very sensible to change of physical conditions of a propagation medium. In the classical theory formulation, the waves are guided along the boundary of semi-infinity solid state and free space. A real situation is more complex and a medium commonly consists of two physical components: a solid substrate and a gaseous or liquid environment. In the case of stress-free substrate, the strongest impact on SAW properties have surface electrical and mechanical conditions determined by solids or liquids adhering to the boundary. This impact is utilised for constructing sensors for different gases and vapours e.g. (Jakubik et al., 2007; Hejczyk et al., 2011; Jasek et al., 2012). The influence of gaseous environment on the SAW properties is usually very weak and ignored. However, in certain condition it can be significant enough to be applied to sensor construction. In general, it concerns Rayleigh wave devices where energy leakage phenomenon is perceptible, especially when the gas being detected considerably changes the density of environment. The paper presents the results of experiments with oxygen-nitrogen mixture. Their primary aim was focused on finding the dependence of resonant frequency and attenuation in SAW resonator on parameters and concentrations of the gas in the environment.
Źródło:
Archives of Acoustics; 2020, 45, 3; 483-486
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Finite Element Analysis of SAW Sensor with ZnO Substrate for Dichloromethane (DCM) Gas Detection
Autorzy:
Moustafa, Mohamed
Laouini, Ghaylen
Alzoubi, Tariq
Powiązania:
https://bibliotekanauki.pl/articles/1945651.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
surface acoustic wave
SAW
gas sensors
VOCs
FEM modelling
Opis:
A SAW gas sensor based on Zinc Oxide (ZnO) piezoelectric substrate is simulated and evaluated for the detection of the dichloromethane (DCM) volatile organic compound (VOC). The study is performed based on the finite element method (FEM) using COMSOL Multiphysics software. The obtained device response using the ZnO substrate is compared to the one using the typical lithium niobate (LiNbO3) piezoelectric substrate. A thin film of polyisobutylene (PIB) membrane is selected to act as the sensing layer. The obtained results reveal a linear behaviour of the resonance frequency downshift (i.e., the sensor sensitivity) versus the investigated gas concentrations varying from 10 ppm to 100 ppm of DCM gas. Additionally, the sensor response is investigated by applying several thicknesses of PIB ranging from 0.3 µm to 1.0 µm. The observed sensor response shows less dependence on the PIB thickness using the ZnO substrate than the LiNbO3 one.
Źródło:
Archives of Acoustics; 2021, 46, 3; 419-426
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of the Saw System with the PANI + Nafion Sensing Structure for Detection of Low Concentration Carbon Monoxide
Autorzy:
Hejczyk, Tomasz
Pustelny, Tadeusz
Powiązania:
https://bibliotekanauki.pl/articles/1953529.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
Surface Acoustic Wave sensors
carbon monoxide detection
poisonous CO
Opis:
The paper presents a measuring system based on two resonators with a SAW acoustic surface wave. One of the resonators contains a sensor structure consisting of a Nafion layer with a PANI polyaniline nanolayer deposited on it. The sensor structure was tested for carbon monoxide, with a very low concentration (5, 10, 15, 20 ppm) in the atmosphere of synthetic air. The structure sensitivity was tested for two different PANI thicknesses: (100 and 180 nm). The tests were carried out for two different temperatures: 308 K and 315 K. The investigations shows that the measuring system used with the acoustic surface wave together with the proposed sensing layers is sensitive to the presence of low concentration carbon monoxide molecules in the atmosphere of synthetic air.
Źródło:
Archives of Acoustics; 2020, 45, 4; 681-686
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electron Properties Investigation of the Near-Surface Region in Crystalline Semiconductors Using the Transverse Acoustoelectric Effect
Autorzy:
Pustelny, Tadeusz
Powiązania:
https://bibliotekanauki.pl/articles/31339945.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
surface acoustic wave
acoustoelectric effects
electron properties of semiconductors
Opis:
The paper presents the acoustoelectric phenomenon in a layered structure: piezoelectric waveguide – semiconductor. The publication presents an original acoustic method for determining the electrical and electron parameters of the subsurface area in crystalline semiconductors. The method is based on the so-called transverse acoustoelectric effect realized in a layer system: piezoelectric waveguide with Rayleigh surface acoustic wave – semiconductor. The paper discusses the physical foundations of the transverse acoustoelectric effect in the piezoelectric – semiconductor layer system, taking into account the distinctness of the physical properties of the semiconductor near-surface region in relation to its volumetric properties. The work covers many experimental studies of the near-surface region of semiconductors. The original method was presented to determine such surface parameters as: surface potential, surface conductivity, mobility of carriers in the subsurface area, life time of charge carriers in surface states. By means of the acoustic method the following semiconductors have been extensively tested: indium phosphide InP and gallium phosphide GaP. These semiconductors are one of the main semiconductors of group III-V, which are the basis of modern photonics, optoelectronics as well as integrated optics. The work also includes an analysis of the measurement possibilities of the developed acoustic method and its limitations, as well as an analysis of the accuracy of the obtained values of the parameters of the subsurface area of crystalline semiconductors.
Źródło:
Archives of Acoustics; 2022, 47, 4; 565-579
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Study of Interaction of Ultrasonic and Optical Wave in Optical Fiber Using the Air Gap
Autorzy:
Gudra, T.
Muc, S.
Powiązania:
https://bibliotekanauki.pl/articles/177005.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
transmission of acoustic wave
transmission of optical wave
optical fiber
air gap
Opis:
There exist some possibilities for simultaneous delivery of laser radiation and ultrasounds of low frequency and high intensity: introducing ultrasound oscillations in the optical fiber by the rigid connection of the fiber to the vibrating element and non-contact influence of the ultrasonic wave on the laser beam. The article presents the results of Matlab simulations and experimental studies of influence of the ultrasonic wave on the laser beam. A role of the air gap, and its influence on laser- ultrasonic transmission in optical fiber was examined. Advantages and disadvantages of both solutions of interaction of ultrasonic and optical waves in, e.g., surgical applications are discussed.
Źródło:
Archives of Acoustics; 2011, 36, 3; 613-628
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of the SiGMA analysis to the stress evaluation of the cracking structures
Autorzy:
ŚWIT, Grzegorz
TEODORCZYK, Michał
Powiązania:
https://bibliotekanauki.pl/articles/456412.pdf
Data publikacji:
2014
Wydawca:
Uniwersytet Rzeszowski
Tematy:
Quantitative methods
SiGMA analysis
longitudinal acoustic wave
cracking
reinforced concrete
Opis:
The paper presents the method for the elastic wave processing and propagation analysis applied to the reinforced concrete element under load. The quantitative method gives information about structural changes within the material and enables three-dimensional location of local damage. The Sigma analysis based on a waveform of longitudinal waves was chosen for the study. On this base the analysis can locate the place of the concrete deterioration and evaluate the stress which causing cracking. The acoustic emission test was conducted by the industrial apparatus and six piezoelectric sensors. The waveforms of acoustic emission signals were analysed using computer software. The experimental study confirmed the correctness of the analysis on the base of cracking appearing. The Sigma analysis identified tensile stress, shearing stress and both simultaneously. The method can be useful in the early detection of the micro-cracking of the reinforced concrete elements.
Źródło:
Edukacja-Technika-Informatyka; 2014, 5, 1; 676-681
2080-9069
Pojawia się w:
Edukacja-Technika-Informatyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 66

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