Full-field acoustic methods for current velocity inversion require accurate and efficient mathematical models of sound propagation in a range-dependent waveguide with flow. In this paper, an exact coupled-mode representation of the acoustic field is derived. To account for the physics of the problem, normal modes in a corresponding range-independent waveguide are chosen as the local basis. In t...

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 amorphous state of pharmaceuticals has attracted much attention due to its high bioavailability and other advantages. The stability of the amorphous state in relation with the local molecular mobility is important from both fundamental and practical points of view. The acoustic properties of amorphous progesterone, one of the representative steroid hormones, were investigated by using a Bri...

In this paper, a novel analytical method was developed based on statistical energy analysis framework to evaluate sound transmission loss through ventilated windows. The proposed method was compared to numerical and analytical models available in the literature. Results showed the success and advantage of the proposed model in predicting the acoustic performance of the ventilated window and the...

The transformation of acoustic signals into abstract perceptual representations is the essence of the efficient and goal-directed neural processing of sounds in complex natural environments. While the human and animal auditory system is perfectly equipped to process the spectrotemporal sound features, adequate sound identification and categorization require neural sound representations that are...

GLOSSARY OF SYMBOLS r distance from pressure sample point to center of piston a radius of circular radiator R_ dc resistance of driver voice coil ao radius of diaphragm, = _/SD/_r E surface area ay radius of circular vent, = 5/Sv/_r SD effective projected surface area of driver diaphragm c velocity of sound in air, = 343 m/s Sv cross-sectional area of vent ein voltage applied to driver input SP...

in the present work, the influence of aging temperature on mechanical properties and sound velocity of maraging steel m350 was investigated. for this purpose, first, samples were solution annealed at 825◦c for 2 hours and then age hardened at 510◦c-600◦c for 3 hours. hardness, tensile and impact tests were used for determining mechanical properties and longitudinal ultrasonic velocity was used ...

We propose two methods based on the inverse boundary element method (IBEM) for the estimation of acoustic impedances of the interior surfaces of a room. The algorithms take as input the geometrical model of the space, a set of sound field pressures measured at random points and the vibration strength of the sound source. A first approach is a constrained leastsquares method that attempts to fin...

An acoustic cloak is a compact region enclosing an object, such that sound incident from all directions passes through and around the cloak as though the object was not present. A theory of acoustic cloaking is developed using the transformation or change-of-variables method for mapping the cloaked region to a point with vanishing scattering strength. We show that the acoustical parameters in t...

seismic tomography is an imaging technique which creates maps of subsurface elastic properties such as p/s wave velocity, density and attenuation, based on observed seismograms and use of sophisticated inversion algorithms. amongst different acquisition geometries, seismic cross-hole tomography has a special position in geophysical surveys with many applications in hydrocarbons, coal and other ...