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Wyszukujesz frazę "hydroacoustic measurement" wg kryterium: Temat


Wyświetlanie 1-4 z 4
Tytuł:
Analysing the impact on underwater noise of changes to the parameters of a ship’s machinery
Autorzy:
Buszman, Krystian
Powiązania:
https://bibliotekanauki.pl/articles/1573917.pdf
Data publikacji:
2020
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
shipping noise
hydroacoustic passive measurement
narrowband
1/3-octave analysis
diagnosis
classification
Opis:
A ship moving over the surface of water generates disturbances that are perceived as noise, both in the air and under water. Due to its density, water is an excellent medium for transmitting acoustic waves over long distances. This article describes the impact of the settings of a ship’s machinery on the nature of the generated noise. Our analysis includes the frequency characteristics of the noise generated by the moving ship. Data were obtained using an underwater measurement system, and the measured objects were two ships moving on specific trajectories with certain machinery settings. The acquired data were analysed in the frequency domain to explore the possibilities of the acoustic classification of ships and diagnostics of source mechanisms.
Źródło:
Polish Maritime Research; 2020, 3; 176-181
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Observations on relations between marine aerosol fluxes and surface-generated noise in the Southern Baltic Sea
Autorzy:
Markuszewski, P.
Klusek, Z.
Nilsson, E.D.
Petelski, T.
Powiązania:
https://bibliotekanauki.pl/articles/2079072.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
marine aerosol
aerosol flux
noise measurement
underwater noise
sea spray
hydroacoustic measurement
meteorological condition
Baltic Sea
Opis:
This study presents the preliminary results of combining underwater acoustic ambient noise measurements with those of in-situ sea spray fluxes (SSF). Hydroacoustic measurements (in the frequency range 80 Hz –12.5 kHz) were made using an underwater noise recording system developed at the Institute of Oceanology of the Polish Academy of Sciences which was then deployed in the southern Baltic Sea. The simultaneous measurements of coarse sea spray fluxes (with particle diameters ranging from 0.5 to 47 µm) were made on board the r/v Oceania using the gradient method. Observations were conducted for the duration of the passage of an atmospheric front that lasted 2.5 days (60 hours of measurements). There were significant differences in the sound pressure level (SPL) and aerosol fluxes observed between the first part of measurements (developing wave state) and the second part (developed waves). Wave parameters, such as peak period, significant wave height, wave age, and mean wave slope acquired from the WAM (WAve Model), were used to investigate the impact of wave field properties on noise and aerosol flux measurements. We observed different behaviours in the power spectrum density (PSD) levels of noise for these parameters depending on the wave state development.
Źródło:
Oceanologia; 2020, 62, 4PA; 413-427
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Data compression and clustering of one-third-octave spectra by acoustical colors
Autorzy:
Józwiak, R.
Nissen, I.
Listewnik, K.
Powiązania:
https://bibliotekanauki.pl/articles/332570.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
cumulative value
acoustical colors
hydroacoustic measurement
underwater communication
Opis:
This article presents a new approach for the data compression and clustering of one-third octave spectrum by using "acoustical colours". Using in-situ measurements by the IGLOO – sensor nodes it can show that this approach allows a clustering of the colors for a quick look classification. This is helpful using wireless acoustical transmissions with restricted transfer volume in underwater sensor networks without jamming their own measurements.
Źródło:
Hydroacoustics; 2017, 20; 85-92
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evaluation of sound extinction and echo interference in densely aggregated zooplankton
Autorzy:
Gorska, N.
Powiązania:
https://bibliotekanauki.pl/articles/48619.pdf
Data publikacji:
2000
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
fish
zooplankton
aggregation
hydroacoustic measurement
extinction
echo interference
krill
evaluation
Opis:
The investigation of sound extinction and echo interference is important as regards the accurate assessment of the abundance of densely aggregated zooplankton. To study these effects, the analytical model describing sound backscattering by an aggregation of isotropic scatterers (Rytov et al. 1978, Sun & Gimenez 1992) has been extended to the case of densely aggregated elongated zooplankton. The evaluation of the effects in the case of a dense krill aggregation demonstrates that they can be significant and should be taken into account.
Źródło:
Oceanologia; 2000, 42, 3
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-4 z 4

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