Correlation of stage decay and moisture content of Mollucan sau (Albizia falcataria) with ultrasonic amplitude using PC- based ultrasonic technique

Date

4-2002

Degree

Bachelor of Science in Applied Physics

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Emmanuel A Florido

Abstract

A PC-bases detection system using ultrasonic technique was designed and developed for determining the decay of Moluccan Sau (Albizia falcatria). Using the through-transmission instrument set-up, the correlation between ultrasonic wave amplitude to moisture content and weight loss due to decay of the wood was determined. The wave amplitude was measured using a peak-detector for faster collection of data. An ultrasonic piezoelectric sensor was used. A receiver and transmitter pair was configured with 25 KHz as the sending frequency of 6 V peak-to-peak ultrasonic waves. The waveform received was studied further using the Fast Fourier Transform of the signal to derive the power spectrum of the signal. A total of 80 samples were prepared. Thirty samples were used for inoculation of two different fungi, White-rot and the Brown-rot fungi. Only 47 samples were observed and tested. A moderate correlation of -0.54210 between amplitude and % weight loss due to decay was obtained with high level of significance (<0.0001) while a weak correlation of -0.23730 was obtained between amplitude and % moisture content in non-dry samples with no significance (0.1083). When the amplitude of non-dry samples were compared with oven-dried samples, a correlation was obtained with high level of significance (<0.0001). It is possible use ultrasonic techniques in determining stage decay of wood but it is recommend to use a large number of samples in calibrating the instrument .

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

Thesis

Document Type

Thesis

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