. Vibro-acoustography (VA) is an acoustic image modality based on the response of tissue under excitation of two ultrasound beams with different-frequencies. The aim of this paper is to provide a quantitative analysis with experimental measurements of the difference-frequency (DF) pressure generated in VA. This analysis considered the radiation force , the induced acoustic emission, and nonline...

An acoustic vector-sensor consists of three identical but orthogonally oriented acoustic particle-velocity sensors, plus a pressure sensor-all spatially collocated in a point-like geometry. At any point in space, this tri-axial acoustic vector-sensor can sample an acoustic wavefield as a 3 × 1 vector, instead of simply as a scalar of pressure. This vector, after proper self-normalization, would...

The present study originated in the lack of research into achieving underwater total internal reflection (TIR) via the acousto-optic effect. The uniqueness of this technique exists in the fact that it is based on a high sound pressure level which induces a localised change in refractive index of seawater sufficient to achieve total internal reflection within the communication channel. Different...

In the summer of 2003, the Littoral Acoustic Demonstration Center conducted an acoustic characterization experiment for a 21-element marine seismic exploration airgun array of total volume of 0.0588 m(3) (3590 in.(3)). Two Environmental Acoustic Recording System buoys, one with a desensitized hydrophone, were deployed at a depth of 758 m in a water depth of 990 m, near Green's Canyon in the Gul...

The resonant shells of vibratory cylinder gyroscopes are commonly packaged in metallic caps. In order to lower the production cost, a portion of vibratory cylinder gyroscopes do not employ vacuum packaging. However, under non-vacuum packaging conditions there can be internal acoustic noise leading to considerable acoustic pressure which is exerted on the resonant shell. Based on the theory of t...

Premixed combustion in an enclosed chamber is susceptible to large-scale acoustic instability, which manifests as intense pressure fluctuations with predominant peaks at the characteristic acoustic frequencies of the combustor. Such an instability can occur in aeroand rocket engines as well as in land-based gas turbines (e.g., Harrje & Reardon 1972; Yu, Trouve & Daily 1991; Richards & Janus 199...

SoundDuctFlow, a Modelica library for the joint calculation of acoustic and flow quantities in HVAC (Heating, Ventilation and Air Conditioning) ducts is presented. Modeling the sound propagation in ducts by one dimensional acoustic twoport methods is a well-established technique for the acoustic characterization of large HVAC duct networks. Two different approaches of acoustic modeling will be ...

with the aim of identifying failure mechanism in oriented strand boards, failure behavior of wood strands under tensile load was investigated using acoustic emission technique. resinated and unresinated strands were arranged at top, middle and bottom section of the board before pressing. tensile and acoustic emission tests were performed simultaneously on treated and control samples. using tens...

Dissociation rates of dimeric formic (methanoic)-, acetic (ethanoic)and propionic acid in the gas phase were measured over the pressure range 0.01-100 mbar and for temperatures between 290 K and 325 K. Standing acoustic waves in a cylindrical cavity were excited by absorption of amplitude-modulated COz-laser radiation. Consistent sets of kinetic and thermodynamic properties of the dimerfmonomer...

The performance of current virtual acoustic systems is highly sensitive to the geometry of individual ear at high frequencies. The objective of this paper is to study a virtual acoustic system which may not be sensitive to individual ear shape. The incident sound field around ear is reproduced by using a multi-channel headphone. The results of computer simulations show that the desired sound pr...