scholarly journals Experimental observations of diurnal acoustic propagation effects in seagrass meadows on the Dongsha Atoll

2019 ◽  
Vol 146 (3) ◽  
pp. EL279-EL285 ◽  
Author(s):  
Andrea Y. Y. Chang ◽  
Linus Y. S. Chiu ◽  
Michael H.-K. Mok ◽  
Keryea Soong ◽  
Wei-Jhe Huang
Keyword(s):  
Acoustic Propagation ◽  
Seagrass Meadows ◽  
Propagation Effects ◽  
Dongsha Atoll

Acoustic propagation effects on airgun pulses and whale calls in the Beaufort Sea.

2010 ◽  
Vol 127 (3) ◽  
pp. 1757-1757
Author(s):  
Katherine H. Kim ◽  
Aaron Thode ◽  
Charles R. Greene
Keyword(s):  
Beaufort Sea ◽  
Acoustic Propagation ◽  
Propagation Effects

Acoustic propagation effects from saline intrusions across the shelfbreak front off the New Jersey coast in summer.

2010 ◽  
Vol 127 (3) ◽  
pp. 1974-1974
Author(s):  
Arthur E. Newhall ◽  
Ying‐Tsong Lin ◽  
James F. Lynch ◽  
Timothy F. Duda ◽  
Glen G. Gawarkiewicz ◽  
...  
Keyword(s):  
New Jersey ◽  
Acoustic Propagation ◽  
Propagation Effects

scholarly journals Use of shock-wave exposures for accelerating thermal ablation of targeted tissue volumes

2019 ◽  
Author(s):  
Oleg Sapozhnikov ◽  
Wayne Kreider ◽  
Tatiana Khokhlova ◽  
Ari Partanen ◽  
Maria Karzova ◽  
...  
Keyword(s):  
Shock Wave ◽  
Thermal Ablation ◽  
Near Field ◽  
High Amplitude ◽  
Acoustic Propagation ◽  
Tissue Heating ◽  
Duty Cycles ◽  
Propagation Effects ◽  
Target Sites ◽  
Nonlinear Acoustic

In HIFU applications, nonlinear acoustic propagation effects can result in the formation of high-amplitude shocks at the focus, with amplitudes exceeding 100 MPa, leading to a significant increase in tissue heating at target sites. This effect has been used in a new pulsed-HIFU technology termed boiling histotripsy to mechanically liquefy tissue. In boiling histotripsy, such shock-wave millisecond-long pulses are delivered to the target sites at low duty cycles. Similar exposures, delivered at higher repetition rates may benefit thermal HIFU by shortening sonication and treatment times, reducing heating of near field and surrounding tissues, mitigating diffusion and perfusion effects, and providing sharper lesion margins. The goal of this project was to develop shock-enhanced thermal HIFU treatments and test their performance through a combination of simulations and experiments using a clinical Sonalleve V2 MR-HIFU system (Profound Medical Inc., Canada).

Correction of propagation effects in s-band circular polarisation-diversity radars

1987 ◽  
Vol 134 (5) ◽  
pp. 431 ◽  
Author(s):  
D.H.O. Bebbington ◽  
R. McGuinness ◽  
A.R. Holt
Keyword(s):  
Circular Polarisation ◽  
Propagation Effects

ACOUSTIC PROPAGATION IN AN EPOXY RESIN AT VERY LOW TEMPERATURES

1982 ◽  
Vol 43 (C9) ◽  
pp. C9-509-C9-511
Author(s):  
P. Doussineau ◽  
W. Schön
Keyword(s):  
Epoxy Resin ◽  
Low Temperatures ◽  
Acoustic Propagation

Bulk drag coefficient of a subaquatic vegetation subjected to irregular waves: Influence of Reynolds and Keulegan-Carpenter numbers

2020 ◽  
pp. 34-42
Author(s):  
Thibault Chastel ◽  
Kevin Botten ◽  
Nathalie Durand ◽  
Nicole Goutal
Keyword(s):  
Drag Coefficient ◽  
Wave Height ◽  
Wave Attenuation ◽  
Empirical Relationship ◽  
Breaking Waves ◽  
Irregular Waves ◽  
Geometrical Parameters ◽  
Flume Experiments ◽  
Seagrass Meadows ◽  
Artificial Vegetation

Seagrass meadows are essential for protection of coastal erosion by damping wave and stabilizing the seabed. Seagrass are considered as a source of water resistance which modifies strongly the wave dynamics. As a part of EDF R & D seagrass restoration project in the Berre lagoon, we quantify the wave attenuation due to artificial vegetation distributed in a flume. Experiments have been conducted at Saint-Venant Hydraulics Laboratory wave flume (Chatou, France). We measure the wave damping with 13 resistive waves gauges along a distance L = 22.5 m for the “low” density and L = 12.15 m for the “high” density of vegetation mimics. A JONSWAP spectrum is used for the generation of irregular waves with significant wave height Hs ranging from 0.10 to 0.23 m and peak period Tp ranging from 1 to 3 s. Artificial vegetation is a model of Posidonia oceanica seagrass species represented by slightly flexible polypropylene shoots with 8 artificial leaves of 0.28 and 0.16 m height. Different hydrodynamics conditions (Hs, Tp, water depth hw) and geometrical parameters (submergence ratio α, shoot density N) have been tested to see their influence on wave attenuation. For a high submergence ratio (typically 0.7), the wave attenuation can reach 67% of the incident wave height whereas for a low submergence ratio (< 0.2) the wave attenuation is negligible. From each experiment, a bulk drag coefficient has been extracted following the energy dissipation model for irregular non-breaking waves developed by Mendez and Losada (2004). This model, based on the assumption that the energy loss over the species meadow is essentially due to the drag force, takes into account both wave and vegetation parameter. Finally, we found an empirical relationship for Cd depending on 2 dimensionless parameters: the Reynolds and Keulegan-Carpenter numbers. These relationships are compared with other similar studies.

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