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...

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...

sNN = 200 GeV within Landau’s hydrodynamical model. From the measured data on the widths of the pion rapidity spectra, we extract the sound velocity c2s in the early stage of the reactions. It is found that the sound velocity has a local minimum (indicating a softest point in the equation of state, EoS) at Ebeam = 30A GeV. This softening of the EoS is compatible with the assumption of the forma...

Despite the simple design of instruments such as flutes, organs, whistles, and recorders, not all their sound-generation dynamics is understood. The excitation mechanics of these instruments resembles the phenomenon of blowing across the mouth of an empty bottle to induce sound from the bottle. For our experimental setup, such simple resonators were used to probe their sound-generation mechanic...