Abstract:
Since wood is a renewable resources and Malaysia is one of the most forested
countries in the world. Among tropical forest countries, Malaysia supplies 80% of the
tropical sawn timber to international trade. Nowadays, ultrasonic method in
determining the species of Malaysian wood is not so popular in Malaysia. There are a
lot of studies and research on wood had been carried out such as microwave, x-ray
scanning method and ultrasonic method. Previous research showed that many of
researchers using ultrasonic methods to investigate the properties of wood. This
research was done using the ultrasonic method to determine the species of Malaysian
wood. The species of wood is obtained by using ultrasonic diffractometer with the
frequency above 20 kHz. There are five species of wood chosen in this research,
which are Seraya Kitan, Merawan, Balau, Nyatoh and Chengal. The density, hardness
and the reflection of the ultrasonic wave were affected by the moisture content of each
species of wood. The moisture content of each species of wood is dried up using oven
at the temperature of 105
C. The rectangular wooden block size is chosen because the
moisture content of the wood samples was easily to dry up due to the larger surface of
the wood samples. The acoustic wave propagation phenomena in wood are related to
the microstructure of the wood. The ultrasonic signal received can be determine the
species of wood. The relationship between density, hardness and each species of wood
is distinguished. As the density and hardness of the wood increased, the reflection of
the ultrasonic wave is decreased.
