Modelling acoustic scattering, sound speed, and attenuation in gassy soft marine sediments

Mantouka, Agni; Doğan, Hakan; White, P.R.; Leighton, Timothy G.

doi:10.1121/1.4954753

Cited by 35 publications

(41 citation statements)

References 78 publications

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“…Bubbles are the building blocks of several applications from material science and sonochemsitry [6][7][8][9][10] to oceanography [4,5] and medicine [11][12][13]. Dynamics of bubbles are nonlinear and complex [15,[17][18][19][20] and to achieve their full potential in applications we need to have detailed understanding about the bubble response to exposure parameters of the acoustic field.…”

Section: Discussionmentioning

confidence: 99%

“…They form the core of several applications in liquids [1], and in soft and palpable matter (e.g. tissue [1][2][3] or sediments [1,4,5]). When excited by a sound field they can oscillate with amplitudes large enough to destroy most materials [1,6,7]; enhance chemical reactions [8][9][10], and act as healing or diagnostic agents in medicine [11][12][13].…”

Section: Introductionmentioning

confidence: 99%

“…In the 3 models, the first model neglects the thermal effects, the second model includes the thermal effects using linear approximations by introducing an artificial thermal viscosity [50] and the third model includes full thermal effects [49,[51][52][53] (full thermal model). The second model has widely been used in studies related to oceanography [4,5] or ultrasound contrast agent characterization [38][39][40][41][42]). In this paper we call this the linear thermal model.…”

Section: Introductionmentioning

confidence: 99%

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Nonlinear power loss in the oscillations of coated and uncoated bubbles: Role of thermal, radiation and encapsulating shell damping at various excitation pressures

Sojahrood

Haghi

et al. 2020

Ultrasonics Sonochemistry

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A simple generalized model (GM) for coated bubbles accounting for the effect of compressibility of the liquid is presented. The GM was then coupled with nonlinear ODEs that account for the thermal effects. Starting with mass and momentum conservation equations for a bubbly liquid and using the GM, nonlinear pressure dependent terms were derived for energy dissipation due to thermal damping (Td), radiation damping (Rd) and dissipation due to the viscosity of liquid (Ld) and coating (Cd). The dissipated energies were solved for uncoated and coated 2-20 µm bubbles over a frequency range of 0.25f r − 2.5f r (f r is the bubble resonance) and for various acoustic pressures (1kPa-300kPa). Thermal effects were examined for air and C3F8 gas cores in each case. For uncoated bubbles with an air gas core and a diameter larger than 4 µm, thermal damping is the strongest damping factor. When pressure increases, the contributions of Rd grow faster and become the dominant damping mechanism for pressure dependent resonance frequencies (e.g. fundamental and super harmonic resonances). For coated bubbles, Cd is the strongest damping mechanism. As pressure increases Rd contributes more to damping compared to Ld and Td. In case of air bubbles, as pressure increases, the linear thermal model largely deviates from the nonlinear model and accurate modeling requires inclusion of the full thermal model. However, for coated C3F8 bubbles of diameter 1-8 µm, typically used in medical ultrasound, thermal effects maybe neglected even at higher pressures. We show that the scattering to damping ratio (STDR), a measure of the effectiveness of the bubble as contrast agent, is pressure dependent and can be maximized for specific frequency ranges and pressures. 1

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Nonlinear power loss in the oscillations of coated and uncoated bubbles: Role of thermal, radiation and encapsulating shell damping at various excitation pressures

Sojahrood

Haghi

et al. 2020

Ultrasonics Sonochemistry

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“…PACS numbers: 43.25.Yw, 43.35.Bf,43.35.Ei Acoustically excited microbubbles (MBs) are present in a wide range of phenomena; they have applications in sonochemistry [1]; oceanography and underwater acoustics [2,3]; material science [4], sonoluminescence [5] and in medicine [6][7][8][9][10][11][12]. Due to their broad and exciting biomedical applications, it has been stated that˝The future of medicine is bubbles˝ [12].…”

mentioning

confidence: 99%

“…Linear approximations, however, are not valid for the typical exposure conditions encountered in biomedical applications. In an effort to incorporate the nonlinear MB oscillations in the attenuation estimation of bubbly media, a pressure-dependent MB scattering cross-section has been introduced [2,25]. While the models introduce a degree of pressure dependency (e.g.…”

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confidence: 99%

Pressure dependence of the attenuation and sound speed in a bubbly medium: Theory and experiment

Sojahrood

Haghi

et al. 2016

Journal of the Acoustical Society of America

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Results of the measurements of sound speed and attenuation in a bubbly medium are reported. Monodisperse bubble solutions are sonicated with broadband ultrasound pulses with pressure amplitudes ranging between 12.5-100 kPa. Fundamental relationships between the frequency dependent attenuation, sound speed and pressure are established. A new model for the estimation of sound speed and attenuation is derived that incorporates the effect of nonlinear bubble oscillations on the wave propagation in the bubbly media. Model predictions are in good agreement with experimental results. PACS numbers: 43.25.Yw, 43.35.Bf, 43.35.Ei Acoustically excited microbubbles (MBs) are present in a wide range of phenomena; they have applications in sonochemistry [1]; oceanography and underwater acoustics [2, 3]; material science [4], sonoluminescence [5] and in medicine [6][7][8][9][10][11][12]. Due to their broad and exciting biomedical applications, it has been stated that˝The future of medicine is bubbles˝ [12]. MBs are used in ultrasound molecular imaging [6,7] and recently have been used for the non-invasive imaging of the brain microvasculature [7]. MBs are being investigated for site-specific enhanced drug delivery [8][9][10][11] and for the non-invasive treatment of brain pathologies (by transiently opening the impermeable blood-brain barrier (BBB) to deliver macromolecules [9]; with the first in human clinical BBB opening reported in 2016 [8]). However several factors limit our understanding of MB dynamics which consequently hinder our ability to optimally employ MBs in these applications. The MB dynamics are nonlinear and chaotic [13][14][15]; furthermore, the typical lipid shell coatings add to the complexity of the MBs dynamics due to the nonlinear behavior of the shell (e.g., buckling and rupture [16]). Importantly, the presence of MBs changes the sound speed and attenuation of the medium [17][18][19][20][21]. These changes are highly nonlinear and depend on the MB nonlinear oscillations which in turn depend on the ultrasound pressure and frequency, MB size and shell characteristics [17][18][19][20]. The increased attenuation due to the presence of MBs in the beam path may limit the pressure at the target location. This phenomenon is called pre-focal shielding (shadowing) [21,22]. Additionally, changes in the sound speed can change the position and dimensions of the focal region; thus, reducing the accuracy of focal placement (e.g., for targeted drug delivery). In imaging applications, MBs can limit imaging in depth due to the shadowing caused by prefocal MBs [21,22]. In sonochemistry, changes in the attenuation and sound speed impact the pressure distribution inside the reactors and reduces the procedure efficacy [23]. An accurate estimation of the pressure dependent atten-uation and sound speed in bubbly media remains one of the unsolved problems in acoustics [24]. Most current models are based on linear approximations which are only valid for small amplitude MB oscillations [17]. Linear approximations, however, are no...

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Acoustical methodology for determination of gas content in aquatic sediments, with application to Lake Kinneret, Israel, as a case study

Katsnelson

Katsman

Lunkov

et al. 2017

Limnol. Oceanogr. Methods

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The spatial distribution of gaseous methane in the top layer of the sediment of Lake Kinneret (the Sea of Galilee), Israel is quantified using a novel acoustical methodology. Measurements were carried out with low‐frequency sound pulses (200 Hz–2 kHz) for different depths of the lake along the offshore transects. The methodology is based on the correlation of gas content with sound speed and, in turn, with the reflection coefficient of sound waves from sediment. Variations in the free gas content in sediments with water depth obtained using the proposed method show a remarkable agreement with the distribution of organic matter content in and methane fluxes from sediment, both revealed by the preceding studies. This spatially variable pattern can be explained by the specific biogeochemical, hydrodynamic, and bathymetric characteristics of Lake Kinneret. The suggested method is especially suitable for characterizing gassy sediments and highlighting the location of potential methane emissions.

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Modelling acoustic scattering, sound speed, and attenuation in gassy soft marine sediments

Cited by 35 publications

References 78 publications

Nonlinear power loss in the oscillations of coated and uncoated bubbles: Role of thermal, radiation and encapsulating shell damping at various excitation pressures

Nonlinear power loss in the oscillations of coated and uncoated bubbles: Role of thermal, radiation and encapsulating shell damping at various excitation pressures

Pressure dependence of the attenuation and sound speed in a bubbly medium: Theory and experiment

Acoustical methodology for determination of gas content in aquatic sediments, with application to Lake Kinneret, Israel, as a case study

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