The acoustic modality yields non destructive testing techniques of choice for indepth investigation. Given a precise model of acoustic wave propagation in materials of possibly complex structures, acoustical imaging amounts to the so-called acoustic wave inversion. A less ambitious approach consists in processing pulse-echo data (typically, Aor B-scans) to detect localised echoes with the maxim...

A solution for multifrequency plane waves propagating through a dissipative and nonlinear medium is presented. It originates from the well-known Bessel function series ratio for a pure sinusiodal wave, introduced by Cole and Mendousse. The solution is exact. The only limitation, inherited from the single-frequency solution, is the slow convergence of the series when the nonlinearity is very lar...

Human sound localization abilities rely on binaural and spectral cues. Spectral cues arise from interactions between the sound wave and the listener's body (head-related transfer function, HRTF). Large individual differences were reported in localization abilities, even in young normal-hearing adults. Several studies have attempted to determine whether localization abilities depend mostly on ac...

In this work an expression for the solution of the Helmholtz equation for wedge spaces is derived. Such propagation spaces represent scenarios for many acoustical problems where a free field assumption is not eligible. The proposed sound field model is derived from the general solution of the wave equation in cylindrical coordinates, using sets of orthonormal basis functions. The latter are mod...

A unified theory of sound propagation in saturated marine sediments is developed on the basis of a linear wave equation, which includes a new dissipation term representing internal losses arising from interparticle contacts. This loss mechanism, which shows a ‘‘memory’’ or hysteresis, is proposed as being responsible for the acoustic properties of sediments. To accommodate the memory, the loss ...

A theory for the relaxation rates of a test electron and electron temperature in quantum wires due to deformation, piezoelectric acoustical and polar optical phonon scattering is presented. We represent intraand inter-subband relaxation rates as an average of rate kernels weighted by electron wave functions across a wire. We exploit these expressions to calculate phonon emission power for elect...

Composite structures are often used in aircraft because of the advantages offered by a high strength to weight ratio. However, the acoustical properties of these light and stiff structures can often be less than desirable resulting in high aircraft interior noise levels. In this paper, measurements and predictions of the transmission loss of a curved honeycomb composite panel are presented. The...

Audio gunshot recordings can be helpful for crime scene reconstruction, estimation of the shooter's location and orientation, and verification of eyewitness accounts. The audio evidence can include the muzzle blast, the shock wave signature if the projectile is traveling at supersonic speed, and possibly even the characteristic sound of the firearm's mechanical action if the recording is obtain...

Optimizing resonator shapes for maximizing the ratio of maximum to minimum gas pressure at an end of the resonator is investigated numerically. It is well known that the resonant frequencies and the nonlinear standing waveform in an acoustical resonator strongly depend on the resonator geometry. A quasi-Newton type scheme was used to find optimized axisymmetric resonator shapes achieving the ma...