Solid State Science and Technology, Vol. 11, No 1 (2003) 51-58

 

MEASUREMENT OF THERMAL DIFFUSIVITY OF MALAYSIAN WOOD USING PHOTOFLASH AND PHOTOACOUSTIC TECHNIQUES

 

Chia Pei Fung, W. Mahmood Mat Yunus, Zaidan Abdul Wahab, and Paridah Mohd Tahir

Department of Physics, Faculty of Science and Environmental Studies

Universiti Putra Malaysia, 43400 UPM, Serdang, Malaysia.

43400 Serdang, Selangor Darul Ehsan, Malaysia.

 

ABSTRACT

Two experimental arrangements have been used to measure the thermal diffusivity at room temperature  for  ten  species  of  Malaysian  wood  using  photoflash  and  photoacoustic  (PA) techniques.  Both  use  circular  disc  samples  with  thickness  1  to  2  mm  and  100  to  200  μm

respectively. In the photoflash experiment, a flash pulse is irradiated onto the front surface of the

sample. The time dependence of the temperature response at the back surface of the sample is measured using a K-type thermocouple. On the other hand, the PA experimental configuration uses a closed photoacoustic (PA) cell that serves as a pressure sensor as well as an acoustic chamber. It is based upon the measurement of the acoustic signal as a function of the modulation frequency in the region where the sample is thermally thick. Both experimental data are then used to calculate thermal diffusivity using appropriate analytical expressions. Scanning electron microscopy (SEM) observation has also been done on both radial and tangential surface of the samples. The results are in good agreement within experimental error, hence validating the experimental measurements.

 

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REFERENCES

[1]        G. T. Tsoumis, 1991. Science and Technology of Wood: structures, properties and utilization: New York.

[2]         H. Kubler, 1980. Wood as Building and Hobby Material: John Wiley & Sons.

[3]       W.J.Parker, R.J.Jenkins, C.P.Butler and G.L.Abbott, 1961. Journal of Applied physics 32(9).

[4]         J. J. Alvarado, 1994. J. Appl Phys. 76(11) 7217.

[5]         G. Leon, J. Cruz-de-Leon, L. Villasenor, 2000. Meas Sci Technol  58(2000) 241

[6]        L.M. Clark, R.E. Taylor, 1975. J.Appl. Phys. 46 (2): 714. [7]           J.A.

[7]        Cape, G.W.Lehman, 1963. J. Appl. Phys. 34 (7) 1909.

[8]       Forest  Products  Laboratory,  1989.  Handbook  of  Wood  and  Wood-Based Materials for Engineers, Architects, and Builders: US Department of Agricultural.

[9]        K.D.Maglic and R.E Taylor, 1992. Compendium of thermophysical property

measurement methods 2, Plenum Press, New York, London.

[10]     Rosenwaig and A. Gersho, 1976. J. Appl. Phys. 47(1): 64.