We first describe the picosecond acoustic interferometry study of GaAs with twocolors pump-probe laser pulses. The dependence of the generation process on the pump wavelength and the detection process on the probe wavelength both can cause the shift in the phase of the Brillouin signal. Secondly, in order to distinguish the short high frequency wideband acoustic pulse from low frequency Brillou...

AR = cavity aspect ratio a = speed of sound b = cavity half-width ~ C = dynamic compressibility c = phase speed cp = specific heat at constant pressure f = frequency H = cavity depth k = wave number m = propagation constant P = pressure Pr = Prandtl number R = reflection coefficient p = acoustic pressure pi = initial pulse amplitude Re = acoustic Reynolds number s = cavity spacing T = temperatu...

This paper presents the implementation of Linear Frequency Modulation (LFM) pulse compression technique over acoustic waveguides at frequency range (2kHz--3kHz). The medium used for acoustic chirp propagation is air. Real time pulse compression was carried out over DSP kit (TMS320C6713). The obtained range from the compressed pulse accedes to the actual range of the target (sound source). The s...

We study numerically the propagation of an acoustic pulse through a loaded granular material under the hypothesis that the conventional modeling of solid friction used in soft sphere discrete element modeling remains valid at acoustic time scales. As a pulse crosses the material, it temporarily suppresses sliding contacts, making it difficult to prepare states that correspond to experimental co...

Micrometer-scale acoustic waves are highly useful for refined optomechanical and acoustofluidic manipulation, where these fields are spatially localized along the transducer aperture but not along the acoustic propagation direction. In the case of acoustic tweezers, such a conventional acoustic standing wave results in particle and cell patterning across the entire width of a microfluidic chann...

In this paper we have studied the effect of magneto-static field onpropagation of thermal wave generated in metal by pulsed laser. In fact this interactiongenerate acoustic wave in different mechanisms. However, always the commonmechanism in the interactions of laser pulse and metal is the thermo-elastic wavegeneration. Applying the suitable magneto-static field on the s...

Acoustic wave transducers act as cooperative targets for passive, wireless sensing by converting an incoming electromagnetic pulse to an acoustic wave whose velocity is dependent, by design, with a given quantity under investigation. The acoustic wave is delayed and emitted back to the measurement electronics as an electromagnetic pulse by direct piezoelectric effect. In the context of sub-surf...

Geostatistical analysis was used to map traditionally and acoustically sampled populations of soil invertebrates at two different times in a hayfield at Grove Hill, AL, and once in an Auburn, AL, hayfield. The distributions of nearly all the soil invertebrates and their sounds were nonrandom in all three mapping studies. The maps constructed by excavation and acoustic sampling methods were comp...