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Verification is done on the feasibility of a neural network radiometric photothermal depth profiling method by using well-defined artificial samples with varying optical properties across the layers. Accurate reconstructions are obtained for heat source and optical-absorption coefficient profiles from simulated and experimental radiometric signals.

The Rayleigh wave spectroscopy for reconstruction of elasticity of multilayers is examined.

Bessel functions enable the resolution of the problem of plane thermal waves in media having linearly-changing thermal conductivity, when the internal heat sources are not functioning. The solution obtained is accurate, since internal heat source is produced by optical absorption. The linear thermal conductivity is determined by the inverse calculation method.

An application of laser ultrasonics to investigate circumferential waves and their interaction with defects on cylindrical structures is presented. Due to the high effectiveness of the laser line-source generation regime and the broadband nature of the system, circumferential waves could be generated and detected with a wide bandwidth and an excellent signal-to-noise ratio. A clear recognition of multimode wave forms is achieved by two-dimensional Fourier transform signal processing. Measurements were also made on a cylindrical shell with a crack-like defect which was simulated by an artificial groove on the surface of the specimen. The interaction of the circumferential waves with a defect in the inner or outer surface of the thin cylindrical shell has been studied. The results may lead to an application for defect identification at the inner or outer surface of thin cylindrical shells. © 2002 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Presents information on a study which analyzed the observed change in the photoacoustic signal frequency response upon the application of a transverse magnetic field across octylcyanobiphenyl samples in the nematic phase. Schematic diagram of the experimental apparatus; Discussion of thermal diffusivity depth profiling; Random distribution of the centers of mass of the molecules in the nematic phase.

Presents information on a study which discussed an application of the Hamilton-Jacobi formulation of thermal-wave physics to the problem of photoacoustic depth profiling of inhomogenous solids with arbitrary, continuously varying thermal diffusivity profiles. Evaluation of the Hamilton-Jacobi thermal harmonic oscillator; Solution to the inhomogenous problem; Discussion of the condensed phase media in the photoacoustic saturation regime.