An innovative turbine blade utilizing the excitation mechanism of flow-induced oscillation is proposed, and its principle of rotation is derived theoretically. The energy harvesting performance of this new blade with semi-elliptical cross-section is examined in the waterway and the water tank experiments. The effect of the cross-sectional aspect ratio e of the semi-elliptical cylinder blade was examined within e = 2 ~ 8, and the aspect ratio of e = 6 provided the highest performance in energy harvesting. The power coefficient generated by the blade rose rapidly with increasing flow speed, and it became constant in high flow speed range. On the other hand, the power coefficient kept rising with increasing blade length, and then this implies that longer blades would provide higher performance. However, the power coefficient is expected to become constant with further increase in blade length according to theoretical constraints.

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 The evaluation of pipe wear is necessary for development of seafloor massive sulfides. The authors conducted three types of the flow loop wear experiment to obtain the basic data of pipe wear during slurry transport. In the experiments, the differentials of pipe wear among inner material and the effect of pipe inclination on the wear were investigated. As a result, the wear resistance of SUS304 was higher than plastic and rubber, the wear volume was largest in 30 degrees of inclination angle in the experiment. Then the influence of solids degradation on the wear rates was also investigated. We estimated the decrements of wall thickness in the lifting pipe based on the results of the flow loop wear experiments. As the result of this estimation, it was estimated that the time required for decrements of 1mm in a rigid riser of SUS304 was 88 days.

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