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Show 1 Combustion Control Using Infrared Tunable Acoustooptic Filters as a Smart Sensor for O n Line Determination of Gas Temperature and Composition Michael J. Bardash Stephen M . Beyers Frederick. C. Gouldin George J. Wolga Cornell University As fossil fuel becomes more precious, and, as environmental agencies become more concerned about combustion by-products, a need for smart remote sensors becomes apparent. These sensors should: monitor the temperature and chemical makeup of an exhaust gas stream, cktermine the burner's conditions from this information, and, then adjust the burner to run both cleaner and more efficiently. In addition, remote sensors should not affect the burner's normal operation and should require little maintenance. Presently most exhaust monitors analyze a small sample of the gas flow, and therefore provide only a local reading of that flow. Since infra-red absorption spectra of most exhaust gases are quite well known, w e can, by performing an absorption measurement across the stream, measure the partial pressures of the different constituent gases as well as cktermine the gas temperature optically. Unfortunately, conventional spectroscopic systems are not well suited for remote operation, especially in a harsh environment, so, w e have developed a rugged, computer controlled spectrometer using a tunable acoustooptic filter (TAOF). A TAOF is a crystallographically oriented biref ringent crystal in which an acoustic strain wave interacts with an input optical wave to yield a diffracted, |