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A critical function of life support systems on board manned spacecraft is to continuously revitalize the ambient air and to maintain its proper composition throughout the duration of the mission. This involves gaseous processes that need continuous monitoring. Sound traveling through a gas propagates at different speeds and attenuates to different degrees depending upon the composition of the gas. We previously justified conceptually the operation of a real-time gaseous process control monitor for gas mixtures based on acoustic attenuation and phase velocity. In the present study, on the theory front, we have refined a non-empirical model of acoustic propagation in polyatomic gases based on quantum mechanics and the kinetic theory of gases.

A Design of Experiments (DOE) approach to wind tunnel testing of performance automobiles is being explored at the Langley Full-Scale Tunnel. Traditional methods for wind tunnel testing have focused on conventional “one factor at a time” (OFAT) methods which have difficulty in unearthing valuable interactive effects between variables. In an effort to better characterize a vehicle's aerodynamic behavior as a function of common variables, an exploratory study was completed using the DOE methodology for a common sedan racecar. A two-level factorial designed experiment with center points produced regression models for the lift, drag, and lift to drag ratio as a function of ride height, grille porosity, and yaw angle. In addition, model adequacy and uncertainty levels were described.

Eleven experienced commercial automotive technicians were recruited and trained to repair IM240 emission failures using a specially developed 30 hour course. The training course emphasized the use of an oscilloscope and a flow chart and wave form strategy to repair vehicles. Each technicians' performance was evaluated based on the repair of three or four in-use Arizona IM240 failures. Pre-training and post-training written tests were also administered. Results from this limited study were encouraging. After the technician training, HC and CO emission levels were reduced by 69% and NOx by 58%. More importantly, most of the technicians learned some new and useful diagnostic and equipment skills which they can immediately apply to their businesses. They also became more motivated to tackle the challenge of repairing vehicles to low transient emissions, and aware of the existence and use of new sophisticated diagnostic tools such as oscilloscopes.