Autor: Didenkulov, I. N. - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Feasibility of a nonlinear acoustic method for monitoring of bubbles and fishes
Autorzy:: Didenkulov, I. N.
Martyanov, A. I.
Selivanovsky, D. A.
Powiązania:: https://bibliotekanauki.pl/articles/331838.pdf
Data publikacji:: 1999
Wydawca:: Polskie Towarzystwo Akustyczne
Opis:: A problem of remote counting of bubbles and fishes in shallow waters is complicated due to strong reverberation. Traditional way to solve this problem is the use of narrow acoustic beams and short pulse signals, but it is not applicable for all the situations, in particular, in rivers. Reverberation can be suppressed by methods of nonlinear acoustics, since signals scattered by nonlinear targets contain frequencies which are different from primary emitted ones. Bubble-like objects (free bubbles or swimbladder fishes) have strong nonlinear responses. In the present paper a difference frequency method of counting of bubble-like objects is theoretically considered. Since such a nonlinear scattering is resonant bubble and fish sizing becomes possible. For moving targets nonlinear acoustic response exhibits a specific frequency shift, which can be used for velocity estimation.
Źródło:: Hydroacoustics; 1999, 2; 273-278
1642-1817
Pojawia się w:: Hydroacoustics
Dostawca treści:: Biblioteka Nauki

Artykuł

Skocz do pozycji: 2.

Tytuł:: Acoustical properties of plankton
Autorzy:: Selivanovsky, D. A.
Stunzhas, P. A.
Didenkulov, I. N.
Powiązania:: https://bibliotekanauki.pl/articles/332305.pdf
Data publikacji:: 1999
Wydawca:: Polskie Towarzystwo Akustyczne
Opis:: Plankton is distributed in all oceans and seas, and therefore its acoustic properties can be essential for underwater acoustics. A sound scattering cross section of plankton can increase due to gas cavities associated with plankton cells. Such gas cavities has been found in many kinds of phyto- and zoo- plankton. The present paper gives results of investigation of plankton gas cavities with different methods. II was found in particular that sound velocity in phytoplankton suspensions varies bofh up and down compared to the sound velocity in pure water. A response of phyto- and zoo- plankton on compression and decompression is studied. It was found that species of euphausiids having long range vertical daily migration use bubbles (swimbladders) lo control their buoyancy, while species living without long vertical migration do nof have swimbladders.
Źródło:: Hydroacoustics; 1999, 2; 51-56
1642-1817
Pojawia się w:: Hydroacoustics
Dostawca treści:: Biblioteka Nauki

Artykuł

Skocz do pozycji: 3.

Tytuł:: Bubble diagnostics with the nonlinear acoustic scattering method
Autorzy:: Didenkulov, I. N.
Martyanov, A. I.
Selivanovsky, D. A.
Pronchatov-Rubtsov, N.V.
Powiązania:: https://bibliotekanauki.pl/articles/332477.pdf
Data publikacji:: 2001
Wydawca:: Polskie Towarzystwo Akustyczne
Opis:: The highly nonlinear response of a bubble to an acoustic excitation makes nonlinear methods possible for bubble observation and sizing. There are various nonlinear acoustic methods of bubble detection. The difference frequency method is described, with application to the bubble concentration measurements in the sea. The results of observations on bubble populations of different sizes with a nonlinear acoustic bubble counter are given. The bubble counter was put in the subsurface ocean layer from the drifting vessel. The unit detected single bubbles of known sizes when they passed through the working volume created by the intersection of high-frequency acoustic beams. Data on bubble concentration are presented and discussed. Experiments on bubble motion diagnostics in the cavitation water jet are also described.
Źródło:: Hydroacoustics; 2001, 4; 43-52
1642-1817
Pojawia się w:: Hydroacoustics
Dostawca treści:: Biblioteka Nauki

Artykuł

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