Temat: sound. - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Autonomous hydroacoustic sound velocity profiler
Autorzy:: Jedel, A.
Marszal, J.
Ostrowski, Z.
Kilian, L.
Powiązania:: https://bibliotekanauki.pl/articles/332093.pdf
Data publikacji:: 2003
Wydawca:: Polskie Towarzystwo Akustyczne
Tematy:: hydroacoustics
sound velocity profiler
Opis:: The paper presents the autonomous hydroacoustic sound velocity profiler collaborating with ordinary PC by small box included interface & battery charger. The measurement and calibration methods and block diagram of the meter are presented as well as principles of operation, data collection, selection and transmission. There are described three versions of this meter - dropped from "normal" ships, installed in the light hull of submarines and casings in the hulls of variable depth sonar antennas.
Źródło:: Hydroacoustics; 2003, 6; 261-266
1642-1817
Pojawia się w:: Hydroacoustics
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Spatial distribution of underwater sound generated by hull of moving ship
Autorzy:: Listewnik, K.
Powiązania:: https://bibliotekanauki.pl/articles/332792.pdf
Data publikacji:: 2009
Wydawca:: Polskie Towarzystwo Akustyczne
Tematy:: underwater sound
ship
acoustics
Opis:: The paper presents the experimental research associated with the spatial distribution of acoustic energy generated by moving ship into the water. The paper present the methodology of evaluations acoustics energy from the mechanisms of ship into the water environment. For that purpose the research of noise spatial distribution over ship's hull were conducted along with the hydroacoustic field. The hull is source of waves of complex surface shape inducing waves of different amplitudes and phases depending on the position of ship's machinery. As a result of the hull vibrations generated wave distribution depending on the primary sources, as the main propulsion units, generators or other mechanisms. This research allowed to determine position of the main noises' sources of acoustics energy of machinery and propulsion system depending on class of ships and to designate spatial distribution of noise generated by hull of moving ship.
Źródło:: Hydroacoustics; 2009, 12; 109-116
1642-1817
Pojawia się w:: Hydroacoustics
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Rotation motion of particles in sound field
Autorzy:: Didenkulov, I.
Ezersky, A.
Selivanovsky, D.
Chernov, V.
Powiązania:: https://bibliotekanauki.pl/articles/332816.pdf
Data publikacji:: 2003
Wydawca:: Polskie Towarzystwo Akustyczne
Tematy:: rotation motion
sound field
Opis:: It is known that sound field produces longitudinal oscillation motion of medium. If there are floating particles in a medium those particles oscillate together with liquid. In this paper we consider dynamics of floating particles, which have rotational oscillations in acoustic field. This novel phenomena produces additional sound attenuation due to viscous damping. In the present paper this effect is analytically described. The expression for sound attenuation in suspensions of such particles and estimations of the value of the effect are obtained, and possible applications are discussed.
Źródło:: Hydroacoustics; 2003, 6; 167-170
1642-1817
Pojawia się w:: Hydroacoustics
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: How does the size distribution of living material influence sound scattering in the sea?
Autorzy:: Szczucka, J.
Powiązania:: https://bibliotekanauki.pl/articles/332270.pdf
Data publikacji:: 2003
Wydawca:: Polskie Towarzystwo Akustyczne
Tematy:: sound scattering
sea
living objects
Opis:: Evaluation of the relative contribution of the living objects with different sizes to sound scattering at sea is presented. The relative contribution to the total scattering depends on two factors: size spectrum of oceanic biomass and individual scattering properties of organisms. Various coefficients in the power function describing dependence of biomass concentration on individual size are tested and compared. Simple high-pass model of scattering is used. Flesh and swimbladder contributions are considered separately.
Źródło:: Hydroacoustics; 2003, 6; 41-48
1642-1817
Pojawia się w:: Hydroacoustics
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Application of non-uniform B-Splines of 2-nd order for description vertical distribution of sound speed in water
Autorzy:: Makar, A.
Powiązania:: https://bibliotekanauki.pl/articles/332798.pdf
Data publikacji:: 2009
Wydawca:: Polskie Towarzystwo Akustyczne
Tematy:: hydroacoustics
B-splines
sound speed
Opis:: Modeling of the vertical distribution of the sound speed in water is useful during determination of the depth on the basis of the acoustic method, modeling refraction phenomena and determination the trajectory of the acoustic wave. For modeling 1D functions (vertical distribution of the sound speed) and 2D (surface of the sea bottom for hydrography) uniform B-Splines was used. In this paper description of uniform B-Splines and description and application of non-uniform B-Splines have been presented.
Źródło:: Hydroacoustics; 2009, 12; 133-140
1642-1817
Pojawia się w:: Hydroacoustics
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Tracking of the broadband source of the underwater noise in the very shallow water conditions
Autorzy:: Grelowska, G.
Kozaczka, E.
Powiązania:: https://bibliotekanauki.pl/articles/331537.pdf
Data publikacji:: 2015
Wydawca:: Polskie Towarzystwo Akustyczne
Tematy:: broadband signals
shallow water
sound propagation
Opis:: The paper contains the results, both theoretical and experimental, connected with the tracking of the underwater noise source as small ships, pontoon, diver and so on. The problem of security in the shallow water area is the challenge for underwater acousticians. In this paper there is taken into account the detection of the sources that move on the surface of the sea or underwater in shallow and very shallow water. The main goal deals with characterization of the sound propagation at the shallow water channel. The next problem is formulation of the sound propagation inside of this acoustic duct including normal mode creations and dispersion of the acoustic energy. When we take into account the small ships noise the two main sources are analyzed. The first one is the vibration energy produced by the mechanisms located inside of the ship hull. The acoustical energy is transformed through structural elements of the hull to surrounding water. This energy propagates as broadband underwater noise. The next source is the ship propeller. The sources of the underwater noise give the some deposit to the total acoustical energy that means the ambient noise. The problem that should be solved is to discover these acoustical disturbances along with their classification, identification and tracking.
Źródło:: Hydroacoustics; 2015, 18; 77-86
1642-1817
Pojawia się w:: Hydroacoustics
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Propagation of pulsed sound signals on a shelf of free tidal sea: effects from coastal eddies and internal waves
Autorzy:: Mikryukov, A.
Popov, O.
Serebryany, A.
Powiązania:: https://bibliotekanauki.pl/articles/331674.pdf
Data publikacji:: 2008
Wydawca:: Polskie Towarzystwo Akustyczne
Tematy:: pulsed sound signal
Black Sea
hydroacoustic
Opis:: A long term experiment on studying fluctuations of the parameters of pulsed sound signals in a shallow sea was carried out in the region of the northeastern coast of the Black sea in autumn, 2004. the data were collected on a 1.2-km fixed propagation pathat a 2-km distance from the coastline. During the entire experimentation, observations of temperature fluctuations near the receiving point were performed by the using the line temperature sensor. Fluctuations of the shape, energy and propagation time of the pulsed signals were studied. an attempt of their relation to the hydrodynamic processes on the shelf was taken. The change in the shape and the energy levelof the signal was analyzed for the moment of passing the anticyclonic topographic eddy over the coastal zone. It was shown that the fluctuations of the propagation time were sometimes as high as 17.6 ms. An enhanceof the short-period acoustic fluctuations accompanying the internsification of the internal waves was observed.
Źródło:: Hydroacoustics; 2008, 11; 279-288
1642-1817
Pojawia się w:: Hydroacoustics
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Ships underwater noise measurements using sound intensity method
Autorzy:: Gloza, I.
Powiązania:: https://bibliotekanauki.pl/articles/332552.pdf
Data publikacji:: 2009
Wydawca:: Polskie Towarzystwo Akustyczne
Tematy:: underwater noise
ships
sound intensity method
Opis:: Ship noise is a most important part of the field of underwater acoustics. Its reduction and monitoring is an important aspect in the performance of underwater acoustic systems and in the habitability of the vessel for the crew and passengers. In naval operations the noise radiated by a ship is also dominant source of information for underwater sonar systems. Sound intensity is the vector quantity which informs us about the sound power flux, the position and the direction of the sound source. The probe tracks the position of source and at the same time, measures the component of sound-intensity vector. Generally only one component of vector sound intensity was measured, perpendicular to a given measurement surface. The sound intensity of a moving source includes effects such as flow noise that are not present when the source is stationary. The accuracy of measuring acoustic intensity using two closely spaced hydrophones by correcting the phase mismatch error by measuring the transfer function between the two detector systems was examined. The two measuring hydrophone instrumentation systems were earlier calibrated. Our results have been obtained using digital methods, where was used PULSE measuring system.
Źródło:: Hydroacoustics; 2009, 12; 53-60
1642-1817
Pojawia się w:: Hydroacoustics
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: The acoustic radiation impedance of a circular membrane vibrating near the three-wall corner
Autorzy:: Rdzanek, W. P.
Rdzanek, W. J.
Szemela, K.
Powiązania:: https://bibliotekanauki.pl/articles/331634.pdf
Data publikacji:: 2008
Wydawca:: Polskie Towarzystwo Akustyczne
Tematy:: sound radiation
acoustic radiation impedance
circular membrane
Opis:: A flat circular membrane is located near the three- wall corner, limited by the three rigid baffles arranged perpendicularly to each other. The problem of sound radiation has been solved using the spectral form of the Green function for this Neumann boundary value problem together with the complete eigenfunction system of the axisymmetric and asymmetric modes of the membrane is excited by a surface vibrating harmonically with respect to time within the vacuum. The membrane is excited by a surface force. The acoustic attenuation 3399effect has been taken into account as well as the influence of the corner baffles. The resultant sound pressure and the resultant acoustic impedance have been presented as their eigenfunction series. The modal, self and mutual, radiation resistance has been presented in the form of the approximation valid within the low frequency vibration range. The low frequency approximation for the modal radiation reactance has been obtained on the basis of the radiation resistance using the Hilbert transform.
Źródło:: Hydroacoustics; 2008, 11; 339-352
1642-1817
Pojawia się w:: Hydroacoustics
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Reflection of low-frequency long-range sound in the ocean
Autorzy:: Didenkulov, I.
Powiązania:: https://bibliotekanauki.pl/articles/332043.pdf
Data publikacji:: 2003
Wydawca:: Polskie Towarzystwo Akustyczne
Tematy:: low frequency
long-range
sound
ocean
underwater
Opis:: Experimental results on energetic characteristics of low frequency (about 200 Hz) underwater channel sound reflection by ocean mountains and islands are presented. lt is investigated also sound penetration into shallow water. Transformation of vertical structure of sound field over continental slope is considered. Continental slope and shelf-wedge reflection coefficients of law frequency sound propagating in the underwater waveguide were measured. Results of the work show that low-frequency sound reflections from large-scale bottom irregularities can be important in ocean acoustics.
Źródło:: Hydroacoustics; 2003, 6; 117-124
1642-1817
Pojawia się w:: Hydroacoustics
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 11.

Tytuł:: 3D sound intensity variability in shallow water in presence of internal waves in SWARM95 experiments
Autorzy:: Badiey, M.
Katsnelson, B.
Lynch, J.
Pereselkov, S.
Siegmann, W.
Powiązania:: https://bibliotekanauki.pl/articles/332334.pdf
Data publikacji:: 2003
Wydawca:: Polskie Towarzystwo Akustyczne
Tematy:: 3D sound
SWARM'95 experiment
acoustic
Opis:: Broadband shot signal data are analyzed from the SWARM'95 experiment to investigate acoustic variability in presence of internal solitons. A 10 to 15 minute temporal variations in the intensity of the received signals were observed. These temporal variations are azimuthally dependent on variability of water column in the presence of internal solitary waves. These fluctuations should be explained by significant horizontal refraction (3D-effects) taking place when orientation of acoustic track is close to direction of the wave front of internal solitons. Analysis on the base of both equation of vertical modes/horizontal rays and PE in horizontal plane is carried out, good agreement between theoretical calculations and experimental data is obtained.
Źródło:: Hydroacoustics; 2003, 6; 101-112
1642-1817
Pojawia się w:: Hydroacoustics
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 12.

Tytuł:: Relationships between acoustical properties and stiffness of soft tissue phantoms
Autorzy:: Gambin, B.
Kruglenko, E.
Byra, M.
Powiązania:: https://bibliotekanauki.pl/articles/332049.pdf
Data publikacji:: 2016
Wydawca:: Polskie Towarzystwo Akustyczne
Tematy:: soft tissue phantoms
elastography
ultrasound attenuation
speed of sound
Nakagami maps
stiffness
Opis:: Polyvinyl-alcohol cryogel is commonly used for soft tissue phantom manufacture. The gel formation from an aqueous solution of polyvinyl-alcohol takes place during the freezing and thawing cycle. The aim of this work was to assess the degree of gel solidification, hence the material stiffness, by means of quantitative ultrasound. We manufactured three phantoms which differed in the number of freezing/thawing cycles. First, tissue phantoms were examined with an elastography technique. Next, we measured the speed of sound and the attenuation coefficient. What is more, the inter structure variations in phantoms were assessed with the Nakagami imaging which quantifies the scattering properties of the backscattered ultrasound echo. Obtained results confirmed the connection between the number of freezing/thawing cycles and the solidification p rocess. We d efined th e bo undary layer as a region which has a different structure than the sample interior. Next, for each phantom this layer was extracted based on a Nakagami parameter map. We calculated that the thickness of the boundary layer was lower in samples which were subjected to a larger number of freezing/thawing cycles.
Źródło:: Hydroacoustics; 2016, 19; 111-120
1642-1817
Pojawia się w:: Hydroacoustics
Dostawca treści:: Biblioteka Nauki

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