INHIBITION EFFECT OF LASER, GAMMA RAYS, AND SOME NATURAL PLANT EXTRACTS ON FUNGAL DETERIORATIN ON STUCCO MONUMENTS

Architectural and museum stucco belonging to several civilizations are suffering from microbiological deterioration aspects. Several types of laser, gamma rays and natural plants extract were performed to assess their suitability and sustainability for inhibition of fungal deterioration in stucco models. The Fourth Harmonic of Nd: Yag266 (power density= 71 mW/cm2) is the most potent type in inhibition of fungi in a least time for exposure (20: 30 minutes). Irradiated A. parasiticus stucco mockup confirmed that results. The use of ND-YAG Laser 266 nm (Power density= 7.03x 108W/cm2) was effective in eliminating fungi from stucco models without damaging its surface and preserving the patina layer. The time required to clean 1 cm2 of flat parts of the stucco mockup is 8: 10 min and for 1 cm2 of sunken parts whose depth is 3 mm is 15: 20 min. Gamma ray was successful in elimination of the total tested fungi at the rays level of 750 Kr, without any effects on stucco models. The inhibitory mixture of seed extract of neem and thyme (1:1) was effective in inhibition of fungal infection. The result of the monthly follow-up for a period of six months indicated that the fungal growth appears at the end of the fifth month with a heavy growth within the sunken places and represented by A. niger, A. flauvs and A. flavipes, in a ratio of 34:19:1.