We study the multiple scattering of short-wavelength ultrasound through the force networks in dry and wet glass bead packings under stress. Over long distance scales, the diffusion approximation is shown to describe adequately the transport of elastic waves dominated by shear waves. The recovered transport mean path reveals a short-range correlation of the force chains. Also we observe the dras...

INTRODUCTION Although the role of viscoelasticity in muscle mechanics is well recognized, methods for measurement in situ are limited. Recent advances in elastography have made possible the imaging of viscoelastic moduli within individual muscles [1, 2]. We have investigated a new approach, supersonic shear imaging (SSI), which combines high frame-rate (5kHz) ultrasound with acoustic radiation ...

A sonochemistry-based synthesis method was used to produce nanocrystalline nickel oxide powder with ≈ 20 nm average crystallite diameter from Ni(OH)(2) precursor. Ultrasound waves were applied to the primary solution to intensify the Ni(OH)(2) precipitation. Dried precipitates were calcined at 320°C to form nanocrystalline NiO particles. The morphology of the produced powder was characterized b...

Drying is one of the processes that present higher costs in food processing. Pre-treatments are often used to reduce drying time and consequently its cost. In the past years, our group has studied the use of ultrasonic pre-treatments to induce structural changes in the fruit tissue as to improve the effective water diffusivity during air-drying and consequently reduce air-drying time. This stud...

Very high frame rate ultrasound imaging has recently allowed for the extension of the applications of echography to new fields of study such as the functional imaging of the brain, cardiac electrophysiology, and the quantitative imaging of the intrinsic mechanical properties of tumors, to name a few, non-invasively and in real time. In this study, we present the first implementation of Ultrafas...

Ovarian cancer has the highest mortality of all gynecologic cancers with a five-year survival rate of only 30% or less. Current clinical imaging techniques are limited by poor sensitivity and specificity, and lack the capability of detecting ovarian cancer prior to widespread metastasis. Hence, new imaging techniques that can provide functional and molecular contrasts are needed for improving t...

a tellurium dioxide crystal is presented. The all-optical acousto-optic effect describes the combination of laser generated ultrasound with acousto-optic interaction. Laser generated ultrasound spectra are analyzed for tellurium dioxide using a 266 nm and a 1064 nm pulsed source, and used to characterize the acoustooptic interaction. The interaction is shown to be dominated by longitudinal acou...

In order to verify the effect of ultrasonic waves control invasion golden mussel, Limnoperna fortunei, three experiments were made with different numbers individuals and for each experiment sonicator device was using at 40kHz frequency. addition, tests varied in time days exposure mussels waves. As a result, several mortality decoupling analyzed samples noted, significant differences regarding ...

A new integro-differential equation for diffuse photon density waves (DPDW) is derived within the diffusion approximation. The new equation applies to inhomogeneous bounded turbid media. Interestingly, it does not contain any terms involving gradients of the light diffusion coefficient. The integro-differential equation for diffusive waves is used to develop a 3D-slice imaging algorithm based t...

TOFD technique is based on diffraction of ultrasonic waves on the tips of discontinuities instead of reflection on the interface of discontinuities. When ultrasound is incident at linear discontinuities such as crack diffraction takes place at its extremities in addition to the usual reflected wave. The diffracted energy is emitted over a wide angular range, presumed to originate at the extremi...