Aligning Forces on Wood Particles in an Electric Field
AbstractElectrostatic alignment affords a promising route to improved mechanical properties in anisotropic particleboards aimed at competition with sawn lumber in structural uses. A quartz-fiber torque balance was used to measure the aligning torque exerted on elongated wood particles by DC and AC fields over a range of wood moisture content, field intensity, and frequency. Approximate predicting equations relating aligning torque to relevant process parameters have been developed, which should aid the process designer. The dynamics of free-falling particles in an electric field favors small slender particles and high field intensity for best alignment. However, slender particles have long charge relaxation times and thus require high moisture content for effective alignment in a field of a given frequency.
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