Measurements have been made of ultrasonic shear wave attenuation and sound velocity in highly textured polycrystalline samples of Bi~SrzCaCuzOs+,in magnetic fields up to 9 telsa and at temperatures down to 4.2 K. Magnetic field dependent attenuation peaks and velocity enhancements were found that are in good agreement with theoretical predictions based on the assumptions of the thermally assist...

2014 The sound velocity in water has been measured at ultrasonic and hypersonic frequencies and the results show a negative dispersion in the supercooled region. We present measurements of sound velocity and absorption obtained by Brillouin light scattering which show that the effect of structural relaxation is not observed at 0 °C and frequencies smaller than 7.2 GHz. A correction of the hyper...

Using ultrasonic spectroscopy, the frequency dispersions of ultrasonic velocity and attenuation were measured for single crystal 0.72 Pb(Mg1/3Nb2/3)20.28 PbTiO3 (PMN228%PT! with engineered domain structures in the frequency range of 50–110 MHz. We found that the velocity dispersion and attenuation are very small for the longitudinal wave propagating along @001# of the pseudotetragonal state. Ou...

A fine grain, relaxor-based piezoelectric ceramic 0.7 Pb(Mg(1/3)Nb(2/3))O3-0.3PbTiO3 (PMN-30% PT) has been investigated, which was fabricated using the columbite precursor method. The complete set of electromechanical properties of the piezoceramic at room temperature is determined using a combination of ultrasonic and resonance techniques. This fine-grain ceramic (grain size < or = 2.5 microm)...

This paper discusses the use of laser-ultrasonics to monitor the metallurgical transformations of advanced high-strength steels. In this technique, acoustic waves are generated and detected in the material by use of lasers. The ultrasonic velocity can sense the austenite formation/decomposition in real time. Unlike dilatometric measurements the ultrasonic velocity measurements show little influ...

This paper deals with the study of damage produced during freeze-thaw (F-T) cycles using two non-destructive measurement approaches-the first approach devoted to continuous monitoring using embedded sensors during the cycles, and the second one, performing ultrasonic imaging before and after the cycles. Both methodologies have been tested in two different types of concrete specimens, with and w...