Liquids in the Leidenfrost state were shown by Linke to self-propel if placed on ratchets. The vapour flow below the liquid rectified by the asymmetric teeth entrains levitating drops by viscosity. This effect is observed above the Leidenfrost temperature of the substrate, typically 200°C for water. Here we show that coating ratchets with super-hydrophobic microtextures extends quick self-propu...

A ceramic–metal composite (cermet) of uranium nitride (UN) particles embedded in a tungsten-molybdenum (W/Mo) alloy matrix is being considered as reactor fuel for nuclear thermal propulsion (NTP). One possible issue the loss fissile atoms during operation. We begin by reviewing historical data that suggest likely mechanism transport free along metal grain boundaries and through cracks to surfac...

Introduction: In this study, the effects of black tea extract of Iranian tea plant (Camellia sinensis var sinensis) and its polyphenolic pigment thearubigins were investigated on mice intestinal transit time. Method: Thearubigins were isolated by liquid-liquid fraction method. The effects of black tea extract and isolated thearubigins on intestinal propulsion were measured by charcoal propulsio...

• Initial coatings improve the microstructure of surrogate fuel elements. coating thickness is crucial in tuning microstructure. Potential for elements with greater than 60 vol.% fissile exists. Higher fractions would result improved efficiency and decreased weight. Nuclear thermal propulsion (NTP), which may utilize cermet fuels, shows promise improving feasibility long-distance space travel. ...

A number of scientific discoveries regarding the nature of atoms and their characteristics were made over a relatively short period of time. These lead to the splitting of the atom and the realization that potentially large amounts of energy could be released in the fissioning of certain nuclides. Work on this was expedited in secret during the Second World War during which time the first nucle...

Current unmanned undersea vehicles (UUVs) are almost exclusively propeller driven designs, which must inherently be optimized for a particular speed, sacrificing low speed manoeuvrability for cruising efficiency. Recently, biomimetic approaches to underwater vehicle propulsion have illuminated the exciting possibilities for performance improvements made possible by emulating fish motion. In par...

The recent trend to design more efficient and versatile ships has increased the variety in hybrid propulsion and power supply architectures. In order to improve performance with these architectures, intelligent control strategies are required, while mostly conventional control strategies are applied currently. First, this paper classifies ship propulsion topologies into mechanical, electrical a...

∗Chair of AIAA’s Electric Propulsion Technical Committee, 2002-2004. Associate Fellow AIAA. Chief Scientist at Princeton University’s Electric Propulsion and Plasma Dynamics Laboratory (EPPDyL). Associate Professor, Applied Physics Group, MAE Department. e-mail: [email protected]. †Presented at the 40th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit, Ft. Lauderdale, FL. Copyrig...

The recent trend to design more efficient and versatile ships has increased the variety in hybrid propulsion and power supply architectures. In order to improve performance with these architectures, intelligent control strategies are required, while mostly conventional control strategies are applied currently. First, this paper classifies ship propulsion topologies into mechanical, electrical a...