Non-Destructive Testing & Evaluation methods are developed to inspect and investigate materials and structures. Ultrasonic Testing is an NDT method can be used for measuring the thickness of objects, as one of its significant applications. The objective of this paper is designing and applying an intelligent UT fuzzy control system for evaluating the thickness of thin metal objects in a range of...

The effect of the force chain network on sound propagation in a granular material is poorly understood. To quantitatively study these effects, we perform acoustics experiments in a two dimensional photoelastic granular material in which force chains are visible. We send acoustic pulses into the material from a point source and measure the effects of this pulse via two methods: accelerometers wi...

The objectives are to investigate the peculiarities of the ultrasound pulse propagation through human extra/intracranial media by mathematical simulation and to confirm the simulation results experimentally by proving the suitability of the ultrasonic time-of-flight measurement method for human intracranial media (IM) physiological non-invasive monitoring. The mathematical model of ultrasound p...

Male gray treefrogs call to attract females under challenging acoustic conditions. At higher chorus densities, there is considerable background noise and a good chance that a male's calls will often be overlapped by calls of other individuals. Call overlap may reduce the probability of mating because females prefer calls with internal pulse structure that is not obscured. With increases in acou...

Picosecond laser ultrasonic techniques for acoustic wave generation and detection have been employed to probe shear acoustic waves in liquid glycerol at gigahertz frequencies. The experimental approach uses a unique laser pulse shaping technique and a crystallographically canted metal layer to generate frequency-tunable transverse acoustic waves, and uses time-domain coherent Brillouin scatteri...

Photoacoustic tomography (PAT) is a novel tomographic imaging paradigm that combines the benefits of ultrasound imaging and optical tomography [8]. When a semitransparent sample is illuminated with a short pulse of electromagnetic energy, then parts of the optical energy become absorbed which in turn induces an acoustic pressure wave inside the sample (see Figure 1.1). The induced acoustic pres...

This paper concerns the segmentation and automatic transcription of acoustic musical signals. First, a method is proposed for estimating the temporal structure of music, the musical meter. The method consists of an acoustic analysis front-end and of a subsequent probabilistic model which performs joint estimation of the meter at three time scales: beat (tactus), measure, and tatum pulse levels....

We report the experimental observation of self-induced modulation instability (MI) in a Brillouin fiber laser made with a solid-core photonic crystal fiber (PCF) with strong anomalous dispersion. We identify this MI as the result of parametric amplification of optical sidebands generated by guided acoustic modes within the core of the PCF. It is further shown that MI leads to passive harmonic m...

The research is a balance of theoretical analysis, numerical simulations, and experimentation in the laboratory and local waters at WHOI. The theories are approximate and have included various ray, volume integration, and modal-series-based solutions. An acoustic pulse-echo laboratory is used to collect backscatter data off of the animals and turbulence over a wide range of acoustic frequencies...

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...