Piezoelectric transducers, long used in the generation and detection of ultrasonic waves, have more recently been the detector of choice for acoustic emission signals. Optical probing methods, however, have several important advantages for acoustic emission studies: (1) they have an inherent broad frequency response, free from mechanical resonances, (2) they do not interfere with the acoustic w...

We studied experimentally the dependence of light emission and phase space boundaries of air bubbles in water on the level of degassing down to low partial pressures of 15 mmHg. We found that the maximum obtainable light intensity increased monotonically by lowering the concentration of dissolved air in water. We also present a new technique to obtain the acoustic pressure (P(a)) and ambient ra...

We perform a comparative statistical analysis between the acoustic-emission time series from the ancient Greek Athena temple in Syracuse and the sequence of nearby earthquakes. We find an apparent association between acoustic-emission bursts and the earthquake occurrence. The waiting-time distributions for acoustic-emission and earthquake time series are described by a unique scaling law indica...

Active control of water losses is an essential strategy to increase the efficiency of urban water supply systems. This work deals with the early detection of leaks occurring in small-diameter service pipes of water distribution networks. Preliminary experiments were conducted in a test facility to assess the sensitivity of Acoustic Emission methods to leaking water flows. Acoustic Emission meas...

In order to effectively differentiate all kinds of defects inside the composites, this paper carries out testing on the internal defects of three-dimensional (3d) braided composites by use of acoustic emission nondestructive detecting technology. It puts forward the processing method for acoustic emission signals for the internal defects of three-dimensional braided composites based on wavelet ...