An apparatus constructed in a simple structure and capable of generating fine air bubbles and includes an apparatus body having a circular column-like internal space defined by a cylindrical inner surface and circular inner surfaces. The suction valve operating current control circuit includes a preliminary control value generator which serves also as an emergency control signal generator for the control of the suction valve if an error occurs in the system at least to permit an orderly engine shutdown procedure. Also provided by the invention are tissue cultures of the soybean variety D6235241 and the plants regenerated therefrom. The system also includes a control system providing control commands to the at least one actuator, the control commands configured to change deformations on the first surface in order to change the convective heat transfer coefficient of the first surface. The method further includes establishing a catalyst nanoparticle material on the mask layer and directly adjacent at least a portion of the exposed portion of the vertical surface.