Measurement of Moisture Content and Density in Birch (Betula pendula) Veneer Using Microwave Technology
The aim of this research was to calibrate moisture content (MC) and density measurements, obtained non- destructively using micro-wave technology, to 1.5mm birch veneer. A further aim was to assess the density distribution of the birch veneer and the how the density varies along the veneer sheet. The sample size was 100 veneer sheets. Before measurement, the veneer sheets were stabilised to four different moisture classes. The nominal moisture contents of the moisture groups were 3％, 6％, 9％ and 13％. After the measurement, each veneer sheet was cut into 50 specimens. In all there were almost 5000 test pieces in which density and moisture content (assesses gravimetrically) were measured manually. The data set was divided into a training set and a test set for calibration of the measurement system to birch. Calibration was done by modelling the relationship between measured quantities and MC and density. With microwave technology the moisture content and density of birch veneer can be measured with good accuracy using the VITKA instrument. The RMS error for MC measurement was between 0,4％-0,9％. The measurement uncertainty of density is bigger than the measuring uncertainty of the moisture content because MC measurement is used in the calculation of the density. The RMS error for the density measurement was between 14kg/m<3> - 32kg/m<3>. With the whole data set we also tested how big the density variation was between and within birch veneer sheets. The density range between sheets was 440kg/m<3> - 610kg/m<3>. Within sheet the density variation is small.
Birch Veneer moisture content density microwave technology
T. Antikainen A. Rohumaa M. Hughes M. Kairi
Laboratory of Wood Technology, Helsinki University of Technology, Finland
国际会议
The Third International Symposium on Veneer Processing and Products(第三届国际胶合板制造技术研讨会)
上海
英文
171-181
2007-10-23（万方平台首次上网日期，不代表论文的发表时间）