Hydrazine scene: It's a gas

摘要

A better methodology for calibrating hydrazine monitors. The MDA 7100 is one of the detectors the U.S. Air Force uses for monitoring hydrazine. It determines the concentration of a test gas by exposing a chemically treated paper tape (Chemcassette) to a sample of the test gas. The Chemcassette reacts with the test gas and changes color in proportion to the concentration of the gas. The detector's built-in firmware has concentration versus optical density response curves used to calculate, record, and display the gas concentration. Three methods exist to perform field calibrations of the MDA 7100: optics calibration, dynamic calibration, and manual calibration. Optics calibration returns the monitor's ability to interpret differences in stain intensity to the same level it was on the day the manufacturer calibrated the unit. It occurs during installation of a fresh Chemcassette detection tape. An optics calibration doesn't assume anything about the MDA 7100 (whether or not the system is in working condition). Dynamic calibration uses a test gas of known concentration. Unlike the optics calibration method, the Chemcassette must be in place when performing a dynamic gas calibration. Manual calibration of the hydrazine monitor is a dynamic calibration you perform when you don't know the concentration of the test gas.