Expanded deployment of Electro-Mechanical Actuators (EMAs) in critical applications has created much interest in EMA Prognostic Health Management (PHM), a key enabling technology of Condition Based Maintenance (CBM). As such, Impact Technologies, LLC is collaborating with the NASA Ames Research Center to perform a number of research efforts in support of NASA's Integrated Vehicle Health Management (IVHM) initiatives. These efforts have combined experimental test stand development, laboratory seeded fault testing, and physical model-based health monitoring in a comprehensive PHM system development strategy. This paper discusses two closely related EMA research programs being conducted by Impact and NASA Ames. The first of these efforts resulted in the creation of an electro-mechanical actuator test stand for the Prognostics Center of Excellence at the NASA Ames Research Center. The second effort is ongoing and is utilizing physics-based modeling techniques to develop an algorithm and software package toolset for PHM of aircraft EMA systems using a hybrid (virtual sensor) approach. 1,2
Medium-resolution transmissivities of water vapor were measured at temperatures between 600 and 1550 K for all-important vibration-rotation bands as well as part of the purely rotational band. Measurements were made with an improved drop tube design, which ensures a relatively isothermal high-temperature gas column. Data were collected with a Fourier-transform-infrared-spectrometer, allowing for much better spectral resolution than most previous high-temperature measurements. The measured data were compared to the HITEMP database, as well as with the data of Phillips for the 2.7μm band of H2O. The data show minor discrepancies with the high-resolution database, particularly at higher temperatures, but, in general, agreement is acceptable.
Medium resolution transmissivities of water vapor were measured at temperatures between 600 K and 1550 K for all important vibration-rotation bands as well as part of the purely rotational band. Measurements were made with an improved drop tube design, which guarantees a truly isothermal high-temperature gas column. Data were collected with an FTIR-spectrometer, allowing for much better spectral resolution than most previous high-temperature measurements. The measured data were compared with the HITEMP database, as well as with the data of Phillips for the 2.7 μm band of H2O. The data show minor discrepancies with the high-resolution database, particularly at higher temperatures, but in general agreement is acceptable.
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