Empirical Distribution Models for Slenderness and Aspect Ratios of Core Particles of Particulate Wood Composites

Abstract

Particle geometry was characterized for particleboard furnish prepared through hydrolysis of finished commercial particleboard procured from six Canadian plants. Particles samples were screened into seven particle size classes. Particles retained on 0.5-mm mesh were considered core particles and further partitioned into core-fine, medium, and coarse. Individual particles were then randomly selected for geometrical characterization and distribution fitting. About 80% of all screened particles by mass were between mesh sizes of 0.5 and 2 mm. There were significant differences in percentage screen masses of all particle sizes between plants. Masses of particle size greater than 1 mm of panels from two plants were significantly higher than the rest (0.05 α-level), whereas another plant had the highest mass of particle sizes retained on the 2-mm mesh. Particles retained on the 1-mm mesh showed the largest percentage mass variation among all plants. It was found that aspect ratio was a better geometrical indicator for predicting screw withdrawal resistance than any of the absolute dimensions, and increase in core-fine particles increases internal bond strength. Based on maximum likelihood and Akaike's Information Criterion, a log normal distribution was the best fit for all geometrical descriptors of most particle types; gamma and two-parameter Weibull were better fits for length and aspect ratio for most medium particles with gamma being the better of the two

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