Copper In Douglas-Fir and Associated Dielectric Changes

Olaf R. Knezevic, R. T. Lin


The dielectric constant, loss tangent, and AC resistivity of 60 Douglas-fir (Psendotsuga menziesii (Mirb.) Franco) heartwood specimens were determined at 100 Hz, 1 kHz, 50 kHz, and 100 kHz before and after treatment with copper sulphate solutions. The copper retentions, based on oven-dry weight before treatment, ranged from 1 to 7%.

Of the three electrical properties, AC resistivity changed most as a result of treatment. This change, a factor of 7, occurred at 100 Hz and with specimens at an estimated 20% moisture content. A statistical analysis showed even changes of this magnitude are insufficient to form a basis for a nondestructive method for estimating copper retention in wood.


<i>Pseudotsuga menziesii</i>;dielectric constant;loss tangent;AC resistivity;wood preservation

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