Probing liquid surface waves, liquid properties and liquid films with light diffraction

Surface waves on liquids act as a dynamical phase grating for incident light. In this article, we revisit the classical method of probing such waves (wavelengths of the order of mm) as well as inherent properties of liquids and liquid films on liquids, using optical diffraction. A combination of simulation and experiment is proposed to trace out the surface wave profiles in various situations (\emph{eg.} for one or more vertical, slightly immersed, electrically driven exciters). Subsequently, the surface tension and the spatial damping coefficient (related to viscosity) of a variety of liquids are measured carefully in order to gauge the efficiency of measuring liquid properties using this optical probe. The final set of results deal with liquid films where dispersion relations, surface and interface modes, interfacial tension and related issues are investigated in some detail, both theoretically and experimentally. On the whole, our observations and analyses seem to support the claim that this simple, low--cost apparatus is capable of providing a wealth of information on liquids and liquid surface waves in a non--destructive way.Comment: 25 pages, 12 figures, to appear in Measurement Science and Technology (IOP

Process Monitoring Using Optical Ultrasonic Wave Detection

Certain microstructural features of materials, such as grain size in metals, porosity in ceramics, and structural phase compositions, are important for determining mechanical properties. Many of these microstructural features have been characterized by ultrasonic wave propagation measurements, such as wave velocity and attenuation. Real-time monitoring of ultrasonic wave propagation during the processing stage would be valuable for following the evolution of these features. This paper describes the application of laser ultrasonic techniques to the monitoring of ceramic sintering. Prior to this work, ultrasonic wave measurements of the sintering of ceramics have been made only through direct contact with the material with a buffer rod [1,2]. Recently, several advances have been made using lasers for both generation and detection of ultrasonic waves in a totally noncontacting manner for material microstructure evaluation [3–5]. Application of laser ultrasonic techniques now opens the possibility for real-time monitoring of materials in very hostile environments as are encountered during processing [6]

Applications of Laser-Ultrasonics to the Automotive Industry

Peer reviewed: YesNRC publication: Ye

Adhesive Bond Testing By Laser Induced Shock Waves

Peer reviewed: YesNRC publication: Ye

Laser-ultrasonic and laser-tapping techniques for probing aerospace composite structures

Peer reviewed: YesNRC publication: Ye

The Use of Laser-Doppler Interferometry Based on a Fabry-Perot Etalon for Shock Adhesion Test Applied to Adhesively Bonded Materials

Peer reviewed: YesNRC publication: Ye

INFRARED PHOTOACOUSTIC SPECTROMETER AND DATA ANALYSIS FOR HETEROGENEOUS OR LIQUID SAMPLES

Le spectromètre photoacoustique présenté permet l'obtention de spectres dans l'infrarouge de matériaux pulvérulents ou liquides.Une manipulation des données enregistrées conduit à une meilleure sensibilité aux variations du coefficient d'absorption. L'analyse du spectre reste cependant qualitative.By using the photoacoustic spectrometer described, infrared spectra of powdery or liquid samples are obtained. A calculation from the recorded dat a leads to a better sensitivity to the variations of the absorption coefficient. However, the spectrum analysis remains qualitative

Simple Laser-Ultrasonic System Using a Single-Frequency Pulsed laser Oscillator

Peer reviewed: NoNRC publication: Ye