Measurement of wood grain angle, moisture content and density using microwaves (Messung der Faserneigung, der Holzfeuchte und der Rohdichte mittels Mikrowellen)
Schajer, G. S. and Orhan, F.
2006 Holz als Roh- und Werkstoff, 64(6): 483-490(8)
Schajer, G. S. and Orhan, F., (2006), "Measurement of wood grain angle, moisture content and density using microwaves (Messung der Faserneigung, der Holzfeuchte und der Rohdichte mittels Mikrowellen)", Holz als Roh- und Werkstoff, 64(6): 483-490(8).
Abstract:
In many wood products manufacturing processes, it is important to ensure that the physical properties of the raw material lie within acceptable ranges and are measured reliably. It is also important for practical use that the measurement process is robust, low-maintenance, fast and preferably non-contacting. This paper describes the development and demonstration of a microwave system for simultaneously identifying wood grain angle, moisture and density. The method involves propagating a microwave beam through the wood and measuring the resulting depolarization, attenuation and phase shift. The wood physical properties can then be identified from these measurements. In a series of measurements, the prototype microwave system successfully identified wood grain angles for hemlock and Douglas fir respectively with standard errors of 0.9กใ and 2.5กใ (measured range = -90กใ to +90กใ), moisture content 1.2% and 1.9% (measured range = 7-28%), moisture density 3.7 kg/m3 and 7.9 kg/m3 (measured range = 40-150 kg/m3, and dry density 16 kg/m3 and 30 kg/m3 (measured range = 325-625 kg/m3).
Schajer, G. S. and Orhan, F. "Microwave Non-Destructive Testing of Wood and Similar Orthotropic Materials." Subsurface Sensing Technologies and Applications, v.6, n.4, pp.293-313, 2005.
Schajer, G. S. and Orhan, F. "Measurement of Wood Grain Angle, Moisture Content and Density Using Microwaves." Proceedings of the 17th Intl. Wood Machining Seminar, Rosenheim, Germany. pp.181-190. 26-28 September, 2005.
http://batman.mech.ubc.ca/~schajer/microwav.htm: LUMBER STRENGTH ESTIMATION USING MICROWAVES
Graduate Student: (vacancy) Supervisor: Prof. Gary S. Schajer Renewable Resources Laboratory, Dept. Mechanical Engineering, University of British Columbia, Vancouver BC, CANADA. V6T 1Z4
This publication in whole or part may be found online at: here.
