15 November 1996 Dynamics of mat consolidation during pressing: what we've learned with our in-press radiation system for pressing wood composites
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Abstract
We have designed a radiation-based system for density measurement of wood composites during pressing. During pressing, heat and mass transfer, consolidation speed and mat characteristics interact to produce a density distribution in the mat that is typified by high surface density and low core density. Measuring density of the wood mat during consolidation is a key parameter for understanding subsequent product performance. The system provides for density measurement at three horizontal planes in the wood mat, at positions of 25 percent, 50 percent, and 75 percent of the mat thickness at any time during the press cycle. The system incorporates three cesium sources and electronic detection equipment, collimated to move in concert with the up-acting press platen. Radiation count data taken at eight counts per second is converted to density. Press position and time are simultaneously recorded with the count data. Experimentation with the system has included radiation measurements in aspen and pine wood mats, incorporating different rates of press closure and furnish moisture content; both variables known to influence formation of the density distribution in the mat. Results are presented that depict density changes in the mat during pressing.
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Paul M. Winistorfer, William W. Moschler, "Dynamics of mat consolidation during pressing: what we've learned with our in-press radiation system for pressing wood composites", Proc. SPIE 2944, Nondestructive Evaluation of Materials and Composites, (15 November 1996); doi: 10.1117/12.259073; http://dx.doi.org/10.1117/12.259073
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KEYWORDS
Sensors

Collimation

Mass attenuation coefficient

Collimators

Signal attenuation

Composites

Cesium

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