Validation of a three-dimensional model for improving the design of multiple-backscattering ultrasonic sensors.

Ultrasonic sensors based on backscattering principles have been developed for various applications involving arbitrary or random scatterer distributions. Although the theory of multiple scattering of waves is well-established, it has not been thoroughly explored in these applications. This work presents a feasible and simplified three-dimensional scattering model to predict the transient response generated by a set of rods positioned in the near field of a 1 MHz water-coupled ultrasonic transducer.

Determination of Partial Propagation Velocity and Partial Isentropic Compressibility Coefficient in Water-Ethanol System.

This study introduces an innovative approach to the layered model, emphasizing the physical-chemical characterization of miscible liquid systems through ultrasonic techniques, with a specific focus on the water-ethanol system used in pharmaceutical formulations. Traditional characterization methods, while effective, face challenges due to the complex nature of solutions, such as the need for large pressure variations and strict temperature control. The proposed approach integrates partial molar volumes and partial propagation velocity functions into the layered model, enabling a nuanced understanding of miscibility and interactions.

Development and Characterization of a Superresolution Ultrasonic Transducer.

Highly sensitive ultrasound probes are needed to expand the capabilities of biomedical ultrasound and industrial nondestructive testing (NDT). Pursuing better imaging quality, while keeping fabrication costs low, is an important trend in the current development of ultrasound imaging systems. In this article, we report the development and characterization of an ultrasonic transducer that (super)focuses ultrasonic waves beyond the so-called diffraction limit, that is, the beamwaist is roughly narrower than one wavelength.

Acoustic spin transfer to a subwavelength spheroidal particle.

We demonstrate that the acoustic spin of a first-order Bessel beam can be transferred to a subwavelength (prolate) spheroidal particle at the beam axis in a viscous fluid. The induced radiation torque is proportional to the acoustic spin, which scales with the beam energy density. The analysis of the particle rotational dynamics in a Stokes flow regime reveals that its angular velocity varies linearly with the acoustic spin.

Acoustic radiation torque exerted on a subwavelength spheroidal particle by a traveling and standing plane wave.

The nonlinear interaction of ultrasonic waves with a nonspherical particle may give rise to the acoustic radiation torque on the particle. This phenomenon is investigated here considering a rigid prolate spheroidal particle of subwavelength dimensions that is much smaller than the wavelength. Using the partial wave expansion in spheroidal coordinates, the radiation torque of a traveling and standing plane wave with arbitrary orientation is exactly derived in the dipole approximation.

Acoustic radiation force due to incident plane-progressive waves on coated spheres.

The acoustic radiation force exerted by a traveling plane wave on a coated sphere was theoretically investigated. After carefully re-calculating the scattering coefficients of a model presented by Mitri [Eur. Phys.