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be carefully monitored. When selecting an interior material for a storage room or studying methods of preventing deterioration, it is very important to consider fully the characteristics of wood VOCs, not only the amount of TVOC.

Since over one million tourists annually visit the Angkor ruins, the effect on the buildings from the vibrations caused by these tourists is a huge problem for maintaining them. Such organisms as bryophytes, which adhere to the surface of the stones of the ruins, is another factor that damages them. Using crowdsourcing and 3D reconstruction technology, we are organizing a proactive preservation project for the Angkor Thom Bayon Temple, which is a world cultural heritage site. We evaluated its damaged parts and visualized the damaged state.

Experiments were carried out to investigate the corrosion and mineralization of carbon steel samples exposed to iron reducing bacteria cultured in a liquid medium. Specifically iron reducing bacteria were cultured under static conditions for 41 days with carbon steel samples. The result showed that a complex (biofilm, bacteria, etc.) was generated by the bacteria and covered the surface of the carbon steel sample. By using a microscope, the corrosion products were revealed to be formed of green and white crystals, or needle-shaped and lozenge crystals by SEM observation. The crystals were vivianite (Fe 2+ 3 (PO 4 ) 2 ・8H 2 O) measuring 50~250 μm. In a corrosion process of an iron material surface, ferrous ion (Fe 2+ ) is dissolved from the iron in a cathode reaction, and generates Fe 3+ oxide as corrosion product. It appears that vivianite can be also generated as corrosion product in an environment rich in Fe 2+ and phosphate by activity of the iron reducing bacteria. Some data on the morphological feature of these corrosion products were obtained.

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