Title :
Fiber characterization in a stationary ultrasonic field
Author :
Brodeur, P. ; Dion, J.L. ; Garceau, J.J. ; Pelletier, G. ; Massicotte, D.
Author_Institution :
Group de Recherche en Electron. Ind., Quebec Univ., Trois-Rivieres, Que., Canada
Abstract :
When subjected to a stationary ultrasonic field, particles of cylindrical shape diluted in water and shorter than one-fourth of the acoustic wavelength migrate to nodal planes of acoustic radiation pressure and reorient parallel to these planes. Based on this phenomenon, a method was developed to characterize the mean dimensions of softwood fiber samples. The aim is to develop an acoustooptical method suitable for online measurements of pulp fiber dimensions in a paper mill. As the resonator operating frequency is 72 kHz, fibers up to 5 mm in length can be measured. The time evolution of the fiber suspension during ultrasonic excitations is monitored with a collimated beam of light. Scattered light signals collected off-axis are functions of the mean fiber dimensions. Results are presented for fiber samples in the mean length range of 0.2 to 3 mm
Keywords :
acousto-optical effects; ultrasonic measurement; wood; 0.2 to 3 mm; 72 kHz; acoustic radiation pressure; acoustooptical method; paper mill; softwood fiber; stationary ultrasonic field; ultrasonic excitations; Acoustic measurements; Acoustic waves; Frequency measurement; Length measurement; Monitoring; Paper mills; Resonant frequency; Shape; Ultrasonic variables measurement; Wavelength measurement;
Conference_Titel :
Ultrasonics Symposium, 1988. Proceedings., IEEE 1988
Conference_Location :
Chicago, IL
DOI :
10.1109/ULTSYM.1988.49425
