The aim of this paper is to show experimentally the possibility to assess acoustic pressure holograms using a light membrane and a scanning laser vibrometer. The velocity of a light membrane placed in an acoustic field can be measured without contact by means of a laser vibrometer. The ideal membrane must be optically reflective, acoustically transparent (as light as possible), impermeable, and...

This study presents the theoretical framework for variational data assimilation of acoustic pressure observations into an acoustic propagation model, namely, the range dependent acoustic model (RAM). RAM uses the split-step Padé algorithm to solve the parabolic equation. The assimilation consists of minimizing a weighted least squares cost function that includes discrepancies between the model ...

Several recent studies have shown that some larval fishes will approach underwater speakers that broadcast reef noise, leading to the hypothesis that larval fishes use acoustic cues to locate reefs for settlement. The purpose of the present study was to examine existing hearing data of fishes in relation to ambient sound levels around reefs to estimate the distance over which reef fish might de...

Due to their Bragg peak, proton beams are capable of delivering a targeted dose of radiation to a narrow volume, but range uncertainties currently limit their accuracy. One promising beam characterization technique, protoacoustic range verification, measures the acoustic emission generated by the proton beam. We simulated the pressure waves generated by proton radiation passing through water. W...

This work analyses the accuracy of numerical Time-Reversal (TR) simulations implemented using two different Time-Reversal Mirror (TRM) configurations for localising and characterising a stationary acoustic dipole source in a mean flow. The forward time evolution of the acoustic fields is simulated by means of the numerical solution of the inhomogeneous 2-D Linearised Euler Equations (LEE) with ...

Acoustic energy density’s dependence on particle velocity as well as acoustic pressure makes it a good candidate for an error signal in an adaptive noise control algorithm. It has been shown that minimizing acoustic energy density often provides more global attenuation of an enclosed sound field than minimizing squared acoustic pressure. Nodal regions in three-dimensional enclosed sound fields ...

PURPOSE The aim of this study is to correlate the intraocular pressure (IOP) change with the acoustic impedance of the cornea, in order to propose a noncontact and noninvasive method for IOP monitoring. METHODS AND MATERIALS A highly focused transducer (frequency 47-MHz; bandwidth 62%) was made to measure the echo from the anterior and posterior surfaces of intact porcine eyes, respectively. ...

(6) If we now assign T0 to be the undisturbed air temperature of the surroundings, p as the small perturbation in pressure due to an acoustic wave and P0 as the ambient pressure we can derive the change in temperature occurring with a passing acoustic wave. ∆T is very small and is approximately ±0.23C with a very high sound level of 140 dB(SPL), ambient temperature of 20C, and an ambient pressu...