Radiation Induced Effects on Wood Materials and Fungi
K. Csupor, F. Divos, E Gönczöl University of Western Hungary, H-9400 Sopron, Ady E. u. 5. Hungary
ABSTRACT
The wood material protection is rather difficult in the case of some fungi because some fungi have high resistance against the wood preservatives. Some wood preservative material is harmful for the environment. This problem induced the question, weather the fungi can be destroyed by radiation. Parallel to the radiation sensitivity study of the fungi, we have tested the wood material itself, to evaluate the radiation effect on mechanical properties.The irradiation was carded out m the "AGROSTER IRRADIATION Ltd." by Co-60 isotope, which emits gamma rays, at 1,173 and 1,332 keV energy. As the primary effect of the gamma irradiation is energy absorbition in the material and the secondary effects are the radiochemical and biological changes. Figure 1 shows the irradiation site. The result of the experiments shows that the effect of the 2 kGy dose fungi irradiation is significant and over 12 kGy no fungi survived the treatment, see figure 2.We have measured the dynamic MOE of five specimens. The dimension was 20*20*300 mm The applied dose level was: 560 kGy, 1040kGy and 1400 kGy, see figure 3. (Remark: The human lethal dose is 7 Gy for gamma radiation.) The conclusions of the preliminary study are:
The deadly gamma dose for fungi (12 kGy) does not change significantly the MOE of wood material. The calculated relative decrease of MOE is less than 0,2%.
The MOE decrease after irradiation depends on the initial MOE of the material. The degradation process induced and accelerated by gamma radiation is higher when the initial MOE is higher, see figure 4.
Publication Source: Proceedings of the 12th International Symposium on Nondestructive Testing of Wood University of Western Hungary, Sopron, 13-15 September 2000, ISBN 963 7180 88 5 Publisher: University of Western Hungary, H 9400 Sopron, P.O.Box 132, FAX: +36 99 311 103
