Acoustic characterization of seafloor habitats on the western continental shelf of India

Abstract Chakraborty, B., Mahale, V., Navelkar, G., Rao, B. R., Prabhudesai, R. G., Ingole, B., and Janakirinam, G. 2007. Acoustic characterization of seafloor habitats on the western continental shelf of India. – ICES Journal of Marine Science, 64: 551–558. This is a study of the interaction effects of the dual-frequency (210 and 33 kHz) backscatter signal with seafloor sediment and benthic biota along a transect in water 27–83 m deep offshore of the Goa region of India's central west coast. Estimation of the power-law exponent using seafloor topographic data provided equivalent values even when using dual high-frequency systems for different grain-size sediments. Backscatter signals corrected from system-related gain, etc., reveal better correlations with sedimentary and benthic parameters than the estimated coherence parameters (using echo peaks). Statistically, correlations are significant for the 210 kHz backscatter signal with sand and calcium carbonate (CaCO3) sediment content. Also, correlations are higher for macrobenthic biomass (wet weight) and population density with a 210 kHz backscatter strength, emphasizing the dominant seawater–seafloor interface scattering process. For 33 kHz backscatter strength, the absence of such correlations indicates a different scattering process, i.e. dominant sediment volume scattering attributable to the comparatively lower signal attenuation. Additionally, to validate the results, the backscatter signals from other locations in the vicinity of this transect were considered.

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Acoustic characterization of multi-element, dual-frequency transducers for high-intensity contact ultrasound therapy

10.1063/1.4757305 ◽

2012 ◽

Author(s):

M. Burtnyk ◽

W. A. N'Djin ◽

L. Persaud ◽

M. Bronskill ◽

R. Chopra

Keyword(s):

High Intensity ◽

Ultrasound Therapy ◽

Dual Frequency ◽

Acoustic Characterization

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Acoustic characterization of contrast-to-tissue ratio and axial resolution for dual-frequency contrast-specific acoustic angiography imaging

IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control ◽

10.1109/tuffc.2014.006466 ◽

2014 ◽

Vol 61 (10) ◽

pp. 1668-1687 ◽

Cited By ~ 40

Author(s):

Brooks Lindsey ◽

Juan Rojas ◽

K. Martin ◽

Sarah Shelton ◽

Paul Dayton

Keyword(s):

Dual Frequency ◽

Axial Resolution ◽

Acoustic Characterization

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Acoustic Characterization of Marine Sediments

10.21236/ada627576 ◽

1997 ◽

Author(s):

Anatoliy N. Ivakin ◽

Darrell R. Jackson

Keyword(s):

Marine Sediments ◽

Acoustic Characterization

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Low temperature acoustic characterization of PMN single crystal

Journal of Applied Physics ◽

10.1063/1.5000361 ◽

2017 ◽

Vol 122 (8) ◽

pp. 084103 ◽

Cited By ~ 1

Author(s):

E. Smirnova ◽

A. Sotnikov ◽

S. Ktitorov ◽

H. Schmidt

Keyword(s):

Low Temperature ◽

Single Crystal ◽

Acoustic Characterization

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Characterization of Carrier Phase-Based Positioning in Real-World Jamming Conditions

Remote Sensing ◽

10.3390/rs13142680 ◽

2021 ◽

Vol 13 (14) ◽

pp. 2680

Author(s):

Søren Skaarup Larsen ◽

Anna B. O. Jensen ◽

Daniel H. Olesen

Keyword(s):

Real World ◽

Carrier Phase ◽

Reference Station ◽

Baseline Length ◽

Dual Frequency ◽

Positioning Accuracy ◽

The Impact ◽

Single Versus ◽

Selection Of

GNSS signals arriving at receivers at the surface of the Earth are weak and easily susceptible to interference and jamming. In this paper, the impact of jamming on the reference station in carrier phase-based relative baseline solutions is examined. Several scenarios are investigated in order to assess the robustness of carrier phase-based positioning towards jamming. Among others, these scenarios include a varying baseline length, the use of single- versus dual-frequency observations, and the inclusion of the Galileo and GLONASS constellations to a GPS only solution. The investigations are based on observations recorded at physical reference stations in the Danish TAPAS network during actual jamming incidents, in order to realistically evaluate the impact of real-world jamming on carrier phase-based positioning accuracy. The analyses performed show that, while there are benefits of using observations from several frequencies and constellations in positioning solutions, special care must be taken in solution processing. The selection of which GNSS constellations and observations to include, as well as when they are included, is essential, as blindly adding more jamming-affected observations may lead to worse positioning accuracy.

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Characterization of an Array-Based Dual-Frequency Transducer for Superharmonic Contrast Imaging

IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control ◽

10.1109/tuffc.2021.3065952 ◽

2021 ◽

pp. 1-1

Author(s):

Jing Yang ◽

Emmanuel Cherin ◽

Jianhua Yin ◽

Isabel G. Newsome ◽

Thomas M. Kierski ◽

...

Keyword(s):

Dual Frequency ◽

Contrast Imaging ◽

Frequency Transducer

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Acoustic characterization of silica nanoparticle-impregnated Kevlar fabric

Textile Research Journal ◽

10.1177/00405175211023812 ◽

2021 ◽

pp. 004051752110238

Author(s):

Oluwafemi P Akinmolayan ◽

James M Manimala

Keyword(s):

Transmission Loss ◽

Silica Nanoparticle ◽

Air Gap ◽

Thin Plates ◽

Residual Porosity ◽

Ballistic Performance ◽

Number Of Layers ◽

Structural Applications ◽

Acoustic Characterization

Silica nanoparticle-impregnated Kevlar (SNK) fabric has better specific ballistic performance in comparison to its neat counterparts. For multifunctional structural applications using lightweight composites, combining this improved ballistic functionality with an acoustic functionality is desirable. In this study, acoustic characterization of neat and SNK samples is conducted using the normal-incidence impedance tube method. Both the absorption coefficient and transmission loss (TL) are measured in the 60–6000 Hz frequency range. The influence of parameters such as number of layers of neat or treated fabric, percentage by weight of nanoparticle addition, spacing between fabric layers, and residual porosity is examined. It is found that while absorption decreases with an increase in nanoparticle addition for frequencies above about 2500 Hz, increasing the number of layers shifts peak absorption to lower frequencies. By introducing an air-gap behind the fabric layer, dominant low-frequency (1000–3000 Hz) absorption peaks are obtained that correlate well with natural modes of mass-equivalent thin plates. Examining the influence of residual porosity by laminating the SNK samples reveals that it contributes to about 30–50% of the total absorption. Above about 1500 Hz, 3–5 dB of TL increase is obtained for SNK samples vis-à-vis the neat samples. TL is found to increase beyond that of the neat sample above a threshold frequency when an air-gap is introduced between two SNK layers. With an increase in the weight of nanoparticle addition, measured TL tends to be closer to mass law predictions. This study demonstrates that SNK fabric could provide improved acoustic performance in addition to its ballistic capabilities, making it suitable for multifunctional applications and could form the basis for the development of simplified models to predict the structural acoustic response of such nanoparticle–fabric composites.

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Acoustic Characterization of Some Steel Industry Waste Materials

Applied Sciences ◽

10.3390/app11135924 ◽

2021 ◽

Vol 11 (13) ◽

pp. 5924

Author(s):

Elisa Levi ◽

Simona Sgarbi ◽

Edoardo Alessio Piana

Keyword(s):

Thermal Characteristic ◽

Environmental Benefits ◽

Acoustic Properties ◽

Physical Parameters ◽

Industry Waste ◽

Acoustic Characterization ◽

Minimization Procedure ◽

The Difference ◽

By Products

From a circular economy perspective, the acoustic characterization of steelwork by-products is a topic worth investigating, especially because little or no literature can be found on this subject. The possibility to reuse and add value to a large amount of this kind of waste material can lead to significant economic and environmental benefits. Once properly analyzed and optimized, these by-products can become a valuable alternative to conventional materials for noise control applications. The main acoustic properties of these materials can be investigated by means of a four-microphone impedance tube. Through an inverse technique, it is then possible to derive some non-acoustic properties of interest, useful to physically characterize the structure of the materials. The inverse method adopted in this paper is founded on the Johnson–Champoux–Allard model and uses a standard minimization procedure based on the difference between the sound absorption coefficients obtained experimentally and predicted by the Johnson–Champoux–Allard model. The results obtained are consistent with other literature data for similar materials. The knowledge of the physical parameters retrieved applying this technique (porosity, airflow resistivity, tortuosity, viscous and thermal characteristic length) is fundamental for the acoustic optimization of the porous materials in the case of future applications.

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