Canadian Patents & Development Ltd.

Other

Queen's University at Kingston

American Iron and Steel Institute

Jean F Bussiere

Cheng-Kuei Jen

Jean-Pierre Monchalin

Mohamad Sabsabi

Paolo G Cielo

Michael Sayer

Christian Padioleau

Ahmad Safaai-Jazi

John J Jonas

Daniel Levesque

Martin Lord

Gerald W Farnell

Andre Moreau

Cheng K Jen

Ghislain Vaudreuil

Francois Nadeau

Philippe H Lequeu

Brigitte Bacroix

Marc Dubois

Irina D Makarow

Guanghua Yi

Apparatus and method for detecting shear resonances includes structure and steps for applying a radiation pulse from a pulsed source of radiation to an object to generate elastic waves therein, optically detecting the elastic waves generated in the object, and analyzing the elastic waves optically detected in the object. These shear resonances, alone or in combination with other information, may be used in the present invention to improve thickness measurement accuracy and to determine geometrical, microstructural, and physical properties of the object. At least one shear resonance in the object is detected with the elastic waves optically detected in the object. Preferably, laser-ultrasound spectroscopy is utilized to detect the shear resonances.

Laser-ultrasound spectroscopy apparatus and method with detection of

A method and apparatus for rapid in-situ spectroscopic analysis of preselected components of homogeneous solid chemical compositions, especially pharmaceutical products. The apparatus comprises a high-power pulsed laser whose beam is focused on the material, typically a tablet or the powder prior to compaction into the tablet, which generally consists of an active ingredient (e.g. a drug) and a filler material (cellulose, glucose, lactose, etc.). The pulsed laser beam vaporizes a small volume of the pharmaceutical product and produces a plasma having an elemental composition which is representative of the pharmaceutical product. The atomic composition of the vaporized material is analyzed with an optical spectrometer. As the temperature of the plasma is sufficiently elevated to cause dissociation of the molecules of the constituents of the pharmaceutical product, the concentration of the active ingredient is obtained by analyzing the atomic concentration of an element which is present in the active ingredient but not in the matrix or filler material, or whose concentration in the active ingredient is substantially different from the matrix, and acts as a tag on the active material. The technique can also be used to analyze inactive ingredients or the presence of unwanted contaminants which consist of elements not normally present in such pharmaceutical products such as trace metals introduced accidentally during processing.

Method and apparatus for rapid in situ analysis of preselected

Efficient, simple, miniature and economical piezoelectric and ultrasonic devices employing optical fibers coated with lead-zirconate-titanate (PZT) thin piezoelectric and ferroelectric films are described. The PZT thin films are fabricated chemically by a sol-gel method. Optical fibers can be dipped into the PZT solution, and followed by an annealing and an electric poling process in order to achieve good piezoelectricity in the coated PZT films. This coating process can be devised as an on-line method and thus coating length can be larger than meters. Due to the long coating length, high piezoelectricity, miniature and flexible nature, devices using optical fibers may be used for medical, telecommunication and sensor applications.

Fiber-optic piezoelectric devices

A method of, and apparatus for, evaluating forming capabilities of metal plate by means of ultrasonic waves where the rolling direction and the density of the plate are known. The method comprises the steps of launching acoustic waves into the plate and detecting acoustic waves propagating in the plate to establish acoustic velocities in the plate along at least two different directions. Then the value of a certain plastic strain characteristic, like the average plastic strain ratio R or the planar strain ratio .DELTA.R, is determined from a previously established empirical relationship between the velocities and the value of the plastic strain ratio R(.alpha.).

Method of, and an apparatus for, evaluating forming capabilities of

An elastic waveguide, for propagating acoustic waves, consists of an elongated solid core region and an elongated solid outer cladding region. The acoustic waves propagate in a mode where the principle particle displacement is substantially parallel to the longitudinal axis of the waveguide, this mode is called longitudinal mode. The material densities and the bulk shear wave velocities of the core and cladding region are substantially the same but the bulk longitudinal wave velocity of the cladding region is larger than that of the core region.

Longitudinal mode fiber acoustic waveguide with solid core and solid

The surface acoustic waves are generated by laser beam that is focussed onto a surface to irradiate it in an arcuate pattern as a partial annulus or as a still or moving fringe pattern. The arcuate pattern may be formed by a transmitting or a reflecting axicon, while the fringe pattern may be formed by splitting the laser beam into two beams and directing the two beams to the surface. In addition, a lens or a frequency shifting device may be placed in the path of one of the split beams to form a circular fringe or a moving fringe, respectively.

Efficient laser generation of surface acoustic waves

An acoustic crack detection method and device in which an impact is produced between an actually tested metal piece and an anvil. This impact generates an acoustic wave formed of a plurality of components, one of these wave components being produced by vibrations of the metal piece and having a frequency indicating a cracked or uncracked state of this piece. A microphone senses the acoustic wave generated by the impact and a measuring circuit receives the signal from the microphone for measuring the energy, within a predetermined time gate and within a predetermined frequency bandwidth, of the wave component of interest. The measured energy is compared with a reference level in order to determine if the actually tested metal piece is cracked or not. Of course, the anvil is designed so that its vibrations produced by the impact generate no wave component at a frequency included within the predetermined frequency bandwidth, whereby the crack detection is not disturbed by any acoustic wave component generated by the anvil. The detecting device may be used in an apparatus for sorting cracked and uncracked metal pieces.

Acoustic detection of cracks in metal pieces

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St. Bruno, Canada

Jean F Bussiere