排序方式: 共有2条查询结果,搜索用时 140 毫秒
1
1.
Blen Taye Gemeda Ruth Lahoz Ana Teresa Caldeira Nick Schiavon 《Environmental Earth Sciences》2018,77(2):36
The Lalibela rock-hewn churches are one of the most important religious pilgrimage sites in Ethiopia. These churches are carved from the scoriaceous basalt rock substrate, which has been exposed to attack by biological agents with significant loss of surface material. Particularly, the widespread growth of lichens and other microorganisms on the carved surfaces of the churches has proven to represent a substantial threat for the preservation of the site. In this study, laboratory tests have been conducted to assess the feasibility of using laser technology as an efficient cleaning method of biological patina from polymineralic stone substrates. Multi-analytical techniques were applied for the characterization of the stone samples collected from two of the Lalibela churches: Bete Giyorgis and Bete Amanuel. Stone samples artificially inoculated with bacteria, yeast, fungi isolates, and lichen-encrusted samples were laser cleaned using UV and IR laser wavelengths. The high content of Fe and Ti oxides and the high porosity have made the stone surfaces easily susceptible to low-energy laser treatment. Results indicate that laser cleaning can be applied to polymineralic lithotypes and UV irradiation can successfully remove lichen colonies. Further studies need to be conducted to optimize the laser procedure in polymineralic, high porosity stones. 相似文献
2.
Moisa Mitiku Badasa Merga Biratu Bobo Gemeda Dessalegn Obsi 《Theoretical and Applied Climatology》2022,149(1-2):413-423
Theoretical and Applied Climatology - The paper attempts to investigate the urban heat islands (UHIs) effect driven by land use land cover (LULC) change over Jimma city in southwestern parts of... 相似文献
1