title: Selection of the Rotation Direction for a Camphor Disk Resulting from Chiral Asymmetry of a Water Chamber.
abstract: Self-motion of a camphor disk rotating inside a water chamber composed of two half-disks was investigated. The half-disks were joined along their diameter segments, and the distance between their midpoints (ds) was considered as the control parameter. Various types of camphor disk motions were observed depending on ds. When ds = 0, the chamber had a circular shape, so it was symmetric. A camphor disk showed either a clockwise (CW) or counterclockwise (CCW) rotation with the direction determined by its initial state. The symmetry of the chamber was broken for ds > 0. For moderate distances between the midpoints, a unidirectional orbital motion of the disk was observed. The preferred rotation direction was determined by the shape of the chamber, and it did not depend on the initial rotation direction. For yet larger ds, the unidirectional circular motion was no longer observed and the trajectory became irregular. A mathematical model coupling the camphor disk motion with the dynamics of the developed camphor molecular layer on water was constructed, and the numerical results were compared with the experimental results. The selection of motion type can be explained by considering the influence of camphor concentration on the disk trajectory through the surface tension gradient.
authors: Graduate School of Science, Hiroshima University , 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8526, Japan.
authors: Satoshi
authors: S
authors: Nakata
authors: Graduate School of Science, Hiroshima University , 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8526, Japan.
authors: Hiroya
authors: H
authors: Yamamoto
authors: Department of Physics, Graduate School of Science, Chiba University , 1-33 Inage-ku, Chiba 263-8522, Japan.
authors: Yuki
authors: Y
authors: Koyano
authors: Graduate School of Science, Hiroshima University , 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8526, Japan.
authors: Osamu
authors: O
authors: Yamanaka
authors: Department of Applied Physics, Faculty of Science, Tokyo University of Science , Tokyo 125-8585, Japan.
authors: Yutaka
authors: Y
authors: Sumino
authors: Nobuhiko J
authors: NJ
authors: Suematsu
authors: Department of Physics, Graduate School of Science, Chiba University , 1-33 Inage-ku, Chiba 263-8522, Japan.
authors: Hiroyuki
authors: H
authors: Kitahata
authors: Institute of Physical Chemistry, Polish Academy of Sciences , Kasprzaka 44/52, 01-224 Warsaw, Poland.
authors: Paulina
authors: P
authors: Skrobanska
authors: Institute of Physical Chemistry, Polish Academy of Sciences , Kasprzaka 44/52, 01-224 Warsaw, Poland.
authors: Jerzy
authors: J
authors: Gorecki