ULTRASONIC VELOCITY AND MOISTURE-CONTENT IN WOOD .2. ULTRASONIC VELOCITY AND AVERAGE MOISTURE-CONTENT IN WOOD DURING DESORPTION(1) - MOISTURE-CONTENT BELOW THE FIBER SATURATION POINT
A. Mishiro, ULTRASONIC VELOCITY AND MOISTURE-CONTENT IN WOOD .2. ULTRASONIC VELOCITY AND AVERAGE MOISTURE-CONTENT IN WOOD DURING DESORPTION(1) - MOISTURE-CONTENT BELOW THE FIBER SATURATION POINT, Mokuzai Gakkaishi, 42(6), 1996, pp. 612-617
The relationships between ultrasonic velocity, in the radial and in th
e longitudinal directions, and the average moisture content in wood du
ring desorption from the vapor-saturated condition, were examined. Thi
s included ultrasonic velocity in wood with and without moisture gradi
ents in the moisture range below the fiber saturation point. Six speci
es were used, and their dimensions for measurements in the radial dire
ction differed from those in the longitudinal direction. All faces exc
ept the measuring faces of specimen were coated with parafilm so that
moisture-evaporation took place from one direction in a specimen. Alth
ough the values of ultrasonic velocity were influenced by species and
anatomical directions, the patterns of ultrasonic velocity versus aver
age moisture content curves during desorption almost were independent
of the species in the radial and in the longitudinal directions. When
the relative ultrasonic velocity, ultrasonic velocity at 0% moisture c
ontent, was taken as 100, that of each species was represented by one
equation, and it was possible to estimate the ultrasonic velocity vers
us the average moisture content curves of a species when the ultrasoni
c velocity was known for any moisture content below the fiber saturati
on point. The ultrasonic velocity in wood was influenced little by the
moisture gradients in the direction of the measurement of ultrasonic
velocity.