2012 年 29 巻 1 号 p. 11-15
Clogging of water intake pipes by sessile bivalves is a serious problem hindering the safe operation of industrial and power plants. We developed a system to monitor such clogging by means of an acoustic emission (AE) technique. A sheet-type optical fiber sensor developed in our laboratory was used to monitor AE signals produced by single individuals or colonies of mussel Mytilus galloprovincialis attached by their byssus inside a PMMA pipe. No relation was found between mussel size and peak frequency of AE signal; However, the mussels each had a characteristics frequency, and the scattering of AE signals frequencies corresponded to the number of mussels in a colony. In addition, the AE signal generation rate increased with increasing numbers of mussels in the pipe, but continuous monitoring showed that the signal genera- tion rate also increased when mussels were removed. Continuous monitoring is thus needed if pipe clogging is to be monitored effectively by this AE technique.