| Summary: | 碩士 === 國立嘉義大學 === 林產科學暨家具工程學系研究所 === 97 === The main goals of this study were to investigate the microorganism deterioration of special collections in National Chiayi University (NCYU) library, and to explore the feasibility of Co60 gamma ray (γ-ray) irradiation for disinfecting of paper-based artifacts.
After one year of monitoring for special collections area environment obtained that average temperature and relative humidity (RH) of special collections area are 20.1 oC and 88.3 %, the illumination was between the range of 532 to 926 Lux, and the ultraviolet ray strength was from 51 to 101 μw/Lumen. According to the standards of paper-based relics, it is strongly indicated that the special collections area is need to be improved in order to maintain well storage condition.
The deterioration condition of the fourteen sets of special collections were inspected after having been with an investigation of the conditional report. One of the most serious bio-deteriorations was the mold stain caused by microorganism. By the color analyzed results of the different area of sample, the brightness of molded area was found that lower than that of non-molded one, and the color difference in the front and the behind portion of special collections was higher than that of in the center one. The moisture content (MC) of molded portion was higher than that of non-molded one, and it was also higher that the common books at 9.2 %. The pH value for the sample surface at molded area was about 3 to 6, and was lower than that of the non-molded ones.
About sixteen species of fungi were isolated and identified from the special collections of NCYU library was shown as follow : including Aspergillus flavus, Aspergillus niger var. niger, Aspergillus sydowii, Aspergillus versicolor, Aspergillus sp., Penicillium citrinum, Penicillium glabrum, Penicillium lividum, Penicillium scletiorum, Penicillium sp., Gliocladium caespitosum, Curvularia lunatu., Paecilomyes sp., Cladosporium sp., Trichoderma sp., and Fusarium sp., and the main species were belonged to the genera of Penicillium sp. and Aspergillus sp mostly. For about nine species of fungi isolating from air-spread examination, these airborne fungi, Aspergillus sydowii, Aspergillus versicolor, Penicillium scletiorum, Penicillium citrinum, Penicillium sp., Cladosporium cladosporioides, Gliocladium caespitosum, Curvularia lunatu, and Cladosporium sp., were found in all the molded portion of special collections after having been identified. It is extrapolated that one of possible situations for the fungi on these molded books is from the air.
After storage of paper samples at a room temperature with the RH at 41, 53, 73, 85, and 97 % for 175 days. We found that the fungal growth was vigorously at a higher RH. Moreover, the pH value was lower and the change of color difference was greater than the blank ones, it has shown that the increasing of RH was, the higher MC will obtained. Under 53 % RH at a long period of storage, the samples of paper were able to be maintained with a clear surface. Therefore we suggested that 53 % RH is one of the best possibilities preservation environment (MC about 10 % for the books, and the slight change of color difference).
The dosage load at 3~5 kGy for the γ-ray irradiation was sufficiently to eliminate the fungi on inoculated paper samples, spore suspension, and so as molded papers. The color difference was almost unchanged for the paper samples after having been irradiated at 3 kGy of dosage when the dosage of γ-ray irradiation was higher than 30 kGy, resulted in the decrease of paper strength.
The author has completed the clean process for the molded surface of special collections from the special collections area in NCYU library. From the experimental results, the suggestion methods for the prevention and the removal of microorganism infestation have informed as follow. In the prevention, because air-conditioning system in NCYU library can only maintain the temperature, but not for the RH control, it is therefore suggested that the NCYU library may use an air conditioner and/or a dehumidifier to improve the humidity and/or temperature, as well as the long-term monitoring is necessary by using the humidity recorder. The research results obtained that the humidity control at about 53 % RH was a suitable humidity for paper storage. Besides, to clean such pollutant and molded contamination from the collection books surface is one of the basic prevention methods; that is, cleaning book with a regular time schedule. In the removal of microorganism infestation for the molded portion of books, the study results were suggested that 3~5 kGy of γ-ray irradiation would be an enough dosage to totally disinfect the fungi on the collection books.
|
|---|
