Contra-rotating propellers have renewed interest from the naval architecture community, because of the recent development of electric propulsion drives and podded propulsors. Contrarotating propulsion systems have the hydrodynamic advantages of recovering part of the slipstream rotational energy which would otherwise be lost utilizing a conventional screw propeller system. The application of th...

Concurrent validity and test-retest reliability of the Microsoft Kinect in quantification of manual wheelchair propulsion were examined. Data were collected from five manual wheelchair users on a roller system. Three Kinect sensors were used to assess test-retest reliability with a still pose. Three systems were used to assess concurrent validity of the Kinect to measure propulsion kinematics (...

The authors completed those propulsion system for microsatellite based on the SAFETY FIRST policy and EFFECTIVE COTS, by the beginning of 2008, which can work as both monoand bi-propellant propulsion system and attain wide-range impulse bit and total impulse by switching the monoand bi-propellant modes. We have been devoting ourselves to develop an upgraded version of the propulsion system sice...

This paper describes a methodology for design and optimization of a polymer electrolyte membrane (PEM) fuel cell unmanned aerial vehicle (UAV). The focus of this paper is the optimization of the fuel cell propulsion system and hydrogen storage system for a baseline aircraft. Physics-based models, and experimentally-derived sub-system performance data are used to characterize the performance of ...

Coarse and accurate power accounting methods for ship electric propulsion are observed and compared. For the purpose of analysis, the propulsion system has been separated into two units, namely the ship load and the motor drive. In the load model, variation of such factors like static and dynamic hull resistance and efficiency is explored while the supply characteristics, drive loading, propell...

A basic discussion of the principles of gas chromatography and a description of a combustion gas analyzer using this chemical analysis techniqlJe are presented. During the past several years the combustion gas analyzer has been used extensively in airbreathing propulsion research projects at the APL Propulsion Research Laboratory to analyze samples from supersonic combustion and fuel-air mixing...

A new spacecraft propulsion scheme is proposed which leverages advances in high-energy particle acceleration via laser-plasma interactions. Ponderomotive forces associated with laser wake-fields have demonstrated the potential to accelerate electrons to near-relativistic energies. Different schemes are investigated which may generate efficient propulsion systems for deep-space and manned space ...