RELA??O ENTRE O TEOR DE UMIDADE E A CONSTANTE DIELéTRICA DE ESPéCIES DE MADEIRA DA AMAZ?NIA DURANTE O PROCESSO DE SECAGEM1

摘要

The objective of this study was to determine the relation between dielectric constant and the humidity of six species of wood, by the construction of a capacitor. The material used was non commercialized Amazonian wood, but with high abundance and domination in the National Forest of Tapajós - State of Para, such as: Albizia duckeana (fava-paricá), Brosimum sp. (amapá-doce), Chamaecrista scleroxylon (pau-santo), Qualea dinizii (mandioqueira-rosa), Trattinnickia burserifolia(amescla) and Swartzia laurifolia (gombeira). The samples used to determinate the dielectric constant were made with the dimensions of: 4.5 x 4.5 x 1 cm, defined by preliminary tests made at Forestry Products Laboratory (LPF). The values of capacitance were collected by the construction of a capacitor using a digital multimeter, copper wires, and aluminum plates; and the values were collected eight times with intervals of one hour, during the drying process, starting at saturated mass to constant mass. Therefore, with the collected data the regression curves were established between humidity values and the dielectric constant of wood, which showed a strong correlation between the two variables, showing the direct and proportional influence of the humidity over the dielectric constant. Due to the inexistence of direct relation between specific mass and dielectric constant of the studied species, we suggest new studies to explain the relation between those characteristics.