High-frequency sediment sound speed and attenuation measurements during TREX13 (Target and Reverberation Experiment 2013) with a new portable velocimeter

2013 ◽  
Vol 134 (5) ◽  
pp. 4239-4239 ◽  
Author(s):  
Laurent Guillon ◽  
Xavier Demoulin ◽  
Brian T. Hefner ◽  
Dapeng Zou
Keyword(s):  
High Frequency ◽  
Sound Speed

scholarly journals A diverse group of echogenic particles observed with a broadband, high frequency echosounder

2017 ◽  
Vol 75 (2) ◽  
pp. 471-482 ◽  
Author(s):  
Christian Briseño-Avena ◽  
Peter J S Franks ◽  
Paul L D Roberts ◽  
Jules S Jaffe
Keyword(s):  
Acoustic Waves ◽  
High Frequency ◽  
Sound Speed ◽  
Diverse Group ◽  
Marine Snow ◽  
Frequency Range ◽  
Coastal Regions ◽  
The Past ◽  
Potential Sources ◽  
Acoustic Surveys

Abstract In 1980, Holliday and Pieper stated: “Most sound scattering in the ocean volume can be traced to a biotic origin.” However, most of the bioacoustics research in the past three decades has focused on only a few groups of organisms. Targets such as small gelatinous organisms, marine snow, and phytoplankton, e.g. have been generally to be considered relatively transparent to acoustic waves due to their sizes and relatively low sound speed and density contrasts relative to seawater. However, using a broadband system (ZOOPS-O2) we found that these targets contributed significantly to acoustic returns in the 1.5–2.5 MHz frequency range. Given that phytoplankton and marine snow layers are ubiquitous features of coastal regions; this works suggests that they should be considered as potential sources of backscatter in biological acoustic surveys.

Characteristics of the equations of motion of a reacting gas

1958 ◽  
Vol 4 (3) ◽  
pp. 276-282 ◽  
Author(s):  
L. J. F. Broer
Keyword(s):  
Heat Conduction ◽  
High Frequency ◽  
Sound Speed ◽  
Reaction Rate ◽  
Equations Of Motion ◽  
Sound Waves ◽  
Velocity Of Sound ◽  
Frequency Limit ◽  
Chemically Reacting ◽  
Set Up

The equations of motion for a chemically reacting gas in the absence of viscosity and heat conduction are set up. It is shown that the characteristic speed defined by this set of equations is the high-frequency limit of the phase velocity of sound waves as long as the reaction rate is finite. At infinite reaction rate (chemical equilibrium) the characteristics suddenly change to the lowfrequency sound speed. The nature of this transition is discussed in connection with a recent paper of Resler (1957).

Simulation of Propagating Acoustic Wavefronts with Random Sound Speed

2014 ◽  
Vol 16 (4) ◽  
pp. 1081-1101
Author(s):  
Sheri L. Martinelli
Keyword(s):  
Monte Carlo ◽  
Level Set Method ◽  
Level Set ◽  
High Frequency ◽  
Sound Speed ◽  
Input Data ◽  
Eikonal Equation ◽  
Random Variables ◽  
Full Field ◽  
Sources Of Uncertainty

AbstractA method for simulating acoustic wavefronts propagating under random sound speed conditions is presented. The approach applies a level set method to solve the Eikonal equation of high frequency acoustics for surfaces of constant phase, instead of tracing rays. The Lagrangian nature often makes full-field ray solutions difficult to reconstruct. The level set method captures multiple-valued solutions on a fixed grid. It is straightforward to represent other sources of uncertainty in the input data using this model, which has an advantage over Monte Carlo approaches in that it yields an expression for the solution as a function of random variables.

Biomedical Application of Multimodal Ultrasound Microscope

2012 ◽  
pp. 27-35
Author(s):  
Yoshifumi Saijo
Keyword(s):  
Acoustic Impedance ◽  
High Frequency ◽  
Sound Speed ◽  
High Speed ◽  
Biomedical Application ◽  
3D Structure ◽  
Three Dimensional ◽  
Single Pulse ◽  
Frequency Domain Analysis ◽  
High Frequency Ultrasound

High frequency ultrasound imaging has evolved from the classical acoustic microscope to the multimodal ultrasound microscope, which is available for quantitative C-mode, surface acoustic impedance mode, and three-dimensional (3D)-mode imaging. This evolution has realized both quantitative parametric imaging and easier observation. Quantitative C-mode represents two-dimensional sound speed distribution and is realized by frequency-domain analysis of a single pulse by a high-speed digitizer. Because the square of sound speed is proportional to tissue elasticity, sound speed imaging provides biomechanical information about the tissue. Surface acoustic impedance mode has been used to image fresh brain tissue. High-frequency 3D-mode imaging has been used to visualize the 3D structure of dermis sebaceous glands.

Sign in / Sign up

Export Citation Format

Share Document