Marangoni propulsion is a form of locomotion wherein an asymmetric release of surfactant by a body located at the surface of a liquid leads to its directed motion. We present in this paper a mathematical model for Marangoni propulsion in the viscous regime. We consider the case of a thin rigid circular disk placed at the surface of a viscous fluid and whose perimeter has a prescribed concentrat...

Bubble-propelled catalytic micromotors have recently been attracting much attention. A bubble-propulsion mechanism has the advantage of producing a stronger force and higher speed than other mechanisms for catalytic micromotors, but the nature of the fluctuated bubble generation process affects the motions of the micromotors, making it difficult to control their motions. Thus, understanding of ...

The motion of self-propelled tubular micro- and nanojets has so far been achieved by bubble propulsion, e.g., O2 bubbles formed by catalytic decomposition of H2O2, which renders future biomedical applications inviable. An alternative self-propulsion mechanism for tubular engines on the nanometer scale is still missing. Here, we report the fabrication and characterization of bubble-free propelle...

The ultrasonic propulsion of rod-shaped nanomotors inside living HeLa cells is demonstrated. These nanomotors (gold rods about 300 nm in diameter and about 3 mm long) attach strongly to the external surface of the cells, and are readily internalized by incubation with the cells for periods longer than 24 h. Once inside the cells, the nanorod motors can be activated by resonant ultrasound operat...

Understanding propulsion and adaptation to speed requirements is important in determining appropriate therapies for gait disorders. We hypothesize that adaptations for changing speed requirements occur primarily at the hip. The slow, normal and fast gait of 24 healthy young subjects was analyzed. The linear power was analyzed at the hip joint. The anterior-posterior and vertical induced acceler...

A novel multi-mode spacecraft propulsion concept is presented. The concept combines chemical monopropellant and electric pulsed inductive thruster technology to include shared propellant and shared conical nozzle. Geometry calculations show that existing conical pulsed inductive thruster experiments are typical of large (1000-4000 N) chemical monopropellant thruster nozzles. Performance and pro...

Richard S. Gross (Jet Propulsion laboratory, California institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91 109; ph: 1-818-354-4010; fx: 1-818-393-6890; email: Richard [email protected]. gov) Yi Chao (Jet Propulsion Laboratory, California Institute of Teclmology, 4800 Oak Grove Drive, Pasadena, CA 91 109; ph: 1-818-354-8168; fx: 1-81 8-393-6720; email: [email protected]. gov) Steven L. ...

More electric technologies (METs) play an important role in meeting ever-growing demands for energy efficiency and emission reduction in the maritime transportation sector. As a result, ships with electrical power transmission are becoming popular compared to traditional mechanical power transmission based ships. Hybrid electric propulsion is an intermediate step in this trend where both mechan...

The paper addresses methods of thrust distribution in a propulsion system for an unmanned underwater vehicle. It concentrates on finding an optimal thrust allocation for desired values of forces and moments acting on the vehicle. Special attention is paid to the unconstrained thrust allocation. The proposed methods are developed using a configuration matrix describing the layout of thrusters in...