In this paper, a recently proposed approach to multizone sound field synthesis, referred to as joint pressure and velocity matching (JPVM), is investigated analytically using a spherical harmonics representation of the sound field. The approach is motivated by the Kirchhoff-Helmholtz integral equation and aims at controlling the sound field inside the local listening zones by evoking the sound ...

Single-walled carbon nanotube bundles dispersed in a highly polar fluid are found to agglomerate into a porous structure when exposed to low levels of laser radiation. The phototunable nanoscale porous structures provide an unusual way to control the acoustic properties of the suspension. Despite the high sound speed of the nanotubes, the measured speed of longitudinal-acoustic waves in the sus...

Ultrasound-based diagnostic techniques are now part of the cardiological patients’ chart, while echocardiography is used more often for intraoperative diagnostic as well, as monitoring practices by the anesthesiologist. This article will address the basic physical principles of the ultrasound waves and describe the interactions of ultrasound waves with tissues that lead to the generation of two...

The present work is the successful extension of an improved equation of state (EOS) to refrigerant fluids. The objective is the prediction of isothermal and saturated liquid densities of refrigerants. Two temperature-independent parameters appearing in the modified EOS are closely related to critical point properties of refrigerant fluids. Our results showed that, the proposed EOS can predict w...

We measured the velocity and attenuation of audible sound in the isolated lung of the near-term fetal sheep to test the hypothesis that the acoustic properties of the lung provide a measure of the volume of gas it contains. We introduced pseudorandom noise (bandwidth 70 Hz-7 kHz) to one side of the lung and recorded the noise transmitted to the surface immediately opposite, starting with the lu...

The paper shows how the precise knowledge of the sound field of an ultrasonic annular array can contribute to the development of novel measurement techniques. Emphasis is placed on (a) a non-invasive method for sound velocity measurements in fluids using the echo signals from scattering p]articles, (b) a non-invasive method for the combined determination of thickness and sound velocity in layer...

Sound waves are excited in an optically trapped degenerate Fermi gas of spin-up and spin-down atoms with magnetically tunable interactions. Measurements are made throughout the crossover region, from a weakly interacting Fermi gas through the resonant Fermi superfluid regime to a Bose condensate of dimer molecules. The measured sound velocities test theories of hydrodynamic wave propagation and...