Performance of a Vertical-Axis Wind Turbine with Variable-Pitch Straight Blades by a Pitch-Angle Control Mechanism - KITAMURA, Toshihiro; YOSHIDA, Shinji; YAMADA, Tatsuro; KIWATA, Takahiro; KITA, Tetsuyoshi; TSUCHIDA, Hirokazu; KOMATSU, Nobuyoshi (Proceedings of Japan Wind Energy Symposium, 2008)