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Journal Article

A New Computational Tool for Automotive Cabin Air Temperature Simulation

The thermal comfort inside automotive cabin has been extensively studied for decades. Traditional CFD models provide accurate simulation results of the air temperature distributions inside cabins but at a relatively high computation cost. In order to reduce the computational cost while still providing reasonable accuracy in simulating the air temperature profile inside a mid-sized sedan cabin, this paper introduces a new simulation tool that utilizes a proper orthogonal decomposition (POD) method. The POD method, an interpolation technique, requires only one set of multiple CFD simulations to produce a set of “snapshots”. Later, any simulations that require CFD runs to solve algorithm equation sets can be simplified by using interpolation between the snapshots provided that the geometry of the cabin keeps the same. As a result, the computation time can be reduced to only a few minutes.
Journal Article

Measurement of Smoke Particle Size under Low-Gravity Conditions

Smoke detection experiments were conducted in the Microgravity Science Glovebox (MSG) on the International Space Station (ISS) during Expedition 15 in an experiment entitled Smoke Aerosol Measurement Experiment (SAME). The preliminary results from these experiments are presented. In order to simulate detection of a prefire overheated-material event, samples of five different materials were heated to temperatures below the ignition point. The smoke generation conditions were controlled to provide repeatable sample surface temperatures and air flow conditions. The smoke properties were measured using particulate aerosol diagnostics that measure different moments of the size distribution. These statistics were combined to determine the count mean diameter which can be used to describe the overall smoke distribution.
Technical Paper

The Ranger Telerobotic Shuttle Experiment: Implications for Operational EVA/Robotic Cooperation

The Ranger Telerobotic Shuttle Experiment (RTSX) is a Space Shuttle-based flight experiment to demonstrate key telerobotic technologies for servicing assets in Earth orbit. The flight system will be teleoperated from onboard the Space Shuttle and from a ground control station at the NASA Johnson Space Center. The robot, along with supporting equipment and task elements, will be located in the Shuttle payload bay. A number of relevant servicing operations will be performed-including extravehicular activity (EVA) worksite setup, orbital replaceable unit (ORU) exchange, and other dexterous tasks. The program is underway toward an anticipated launch date in CY2002. This paper gives an overview of the RTSX mission, and describes several follow-on mission scenarios involving cooperative Ranger and EVA activities.
Technical Paper

Quantification of Muscle Fatigue and Joint Position of the Hand During EVA Simulation Operations

Task-based intensity and fatigue metrics were developed and applied to neutral buoyancy simulations of extravehicular activities (EVA). Surface electromyographic (EMG) signals from hand flexor and extensor musculature were recorded during neutral buoyancy EVA simulations at Marshall Space Flgiht Center (MSFC) in August-September 1996. A task intensity index, based on the cumulative histogram of EMG amplitude, was developed and used to determine relative physical difficulty of handgripping, knob turning, bolt manipulation, and j-hook release tasks. A fatigue index, based on the task intensity metric and task duration, was used to provide a measure of task-related fatigue.
Technical Paper

Development of a Power-Assisted Space Suit Glove Joint

The need for improvement of EVA gloves has been identified by NASA and the user community. Particularly important, especially for near to long term goals in the space program, is the need to reduce the fatigue associated with manual tasks. The University of Maryland Space Systems Laboratory (SSL), together with ILC Dover are currently developing an unobtrusive, power-assisted EVA glove that will attempt to provide a suited crewperson with as close to nude-body hand dexterity as possible. The power-assisted joint is designed to provide sufficient force to offset the resistance of the pressurized glove itself, thus alleviating manual fatigue, but provides no additional strength augmentation. This paper describes the initial prototype power-assist mechanism which has been developed, reviewing the relevant design issues and discussing the initial test results from the prototype.
Technical Paper

The Pride of Maryland - A Solar Powered Car for GM Sunraycer USA

The Pride of Maryland is a single seat solar powered trans-continental race car designed and built by engineering students at the University of Maryland. The car competed in G.M. Sunrayce USA, placing third, and has gone on to compete in the World Solar Challenge. This paper outlines the three general areas of design and development for the solar vehicle: aerodynamic, electrical, and mechanical. An exercise in high efficiency, the Pride of Maryland has been extremely successful as both a race car and as an educational tool for training student engineers in “real world” problems.
Technical Paper

An Experimental Investigation of Passenger Car Tire Properties at High Slip and Camber Angles

A newly designed and built Mobile Tire Testing Machine (MTTM) is described that has features for large and continuously variable camber and steering angles with minimum tire scrub. This equipment was used to examine tire properties for six passenger car tires. Of special interest were the tire characteristics at combinations of high slip and camber angle. It was found that camber stiffness decreases with increasing slip angle when the slip and camber angles are both positive, and at limit conditions in slip angle, cambering a tire has little effect on the lateral side force produced. When the slip angle is negative, and the camber angle is positive, preliminary data shows that a greater lateral force is produced when compared to operating at limit conditions in slip angle alone.