Search NASA⌕ Search

Engineering topics

Stokes, David

Publications and source records attributed to Stokes, David.

388 records · Page 22

Proof of Concept Coded Aperture Miniature Mass Spectrometer Using a Cycloidal Sector Mass Analyzer, a Carbon Nanotube (CNT) Field Emission Electron Ionization Source, and an Array Detector

Despite many potential applications, miniature mass spectrometers have had limited adoption in the field due to the tradeoff between throughput and resolution that limits their performance relative to laboratory instruments. Recently, a solution to this tradeoff has been demonstrated by using spatially coded apertures in magnetic sector mass spectrometers, enabling throughput and signal-to-background improvements of greater than an order of magnitude with no loss of resolution. This paper describes a proof of concept demonstration of a cycloidal coded aperture miniature mass spectrometer (C-CAMMS) demonstrating use of spatially coded apertures in a cycloidal sector mass analyzer for the first time. C-CAMMS also incorporates a miniature carbon nanotube (CNT) field emission electron ionization source and a capacitive transimpedance amplifier (CTIA) ion array detector. Results confirm the cycloidal mass analyzer’s compatibility with aperture coding. A >10× increase in throughput was achieved without loss of resolution compared with a single slit instrument. Several areas where additional improvement can be realized are identified. .

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

Final Technical Report: Thermoelectric-Enhanced Cookstove Add-on (TECA) for Clean Biomass Cookstoves

This program seeks to demonstrate a solution to enhance existing biomass cookstove performance through the use of RTI’s Thermoelectric Enhanced Cookstove Add-on (TECA) device. The self-powered TECA device captures a portion of heat from the stove and converts it to electricity through a thermoelectric (TE) device to power a blower. Colorado State University and Envirofit International are partners to support the air injection design and commercialization to enhance combustion in the stove and reduce emissions. Relevance: By demonstrating a proof of concept of the approach with the Envirofit M-5000 stove and TECA device, we hope to apply this technology to existing stoves that are already in use and reduce emissions for stoves that have already found user acceptance to provide a true health benefit. Challenges: The technical challenges include achieving Tier 4 emissions from a biomass stove and for such a stove to operate reliably in the harsh field environment. Additional challenges include the fact that it is difficult to develop a cost effective solution and insure adoption and proper use in the field. Outcomes: In this program we have demonstrated PM emissions at 82 mg/MJd, a 70% reduction as compared to baseline stove operation. We have also developed a stove optimization approach that reduces the number of costly experiments. We have evaluated component-level reliability and will be testing the stove prototype in the field for performance and reliability.

09 BIOMASS FUELS↗