Thermal control surfaces, contamination

Xpert Rule is widely used in industrial and scientific applications, one of them performed in cooperation with NASA and Rockwell Aerospace. It is called NASA s Contamination Control Engineering Design Guidelines Expert System and was developed by Rockwell International s Space Systems Division. It was developed for education in contamination control processes and is designed as an interactive guide to assist with quantifying contamination for sensitive surfaces. The tool enables the user to quantify molecular and particulate contamination requirements for solar arrays, thermal control surfaces, or optical sensors [24],... 

Ceria is effective in the removal of trace amounts of toxic metal species and radionuclides from aqueous solutions and contaminated soils [17], The behaviour of hydrous ceria as selective anion exchanger has also been described in the literature [18] For these applications the preparation of high surface area, thermally and chemically stable ceria phases as well as the study of the parameters which control structural and textural properties of the solid are of particular interest, as they are in the case of the automobile exhaust catalysts... 

In principle, the piezo/cantilever system can reach a force sensitivity of about 10 N. In practice, thermal dilations induce drift of surfaces with respect to each other, reducing the accuracy of the piezo displacement and the sensitivity. For this reason, the micas and the cantilever are closed in a sealed clean chamber, that is temperature-controlled in the range 15- 45°C with an accuracy of 0.05°C. In this way, thermal drifts are reduced to a few tenths of nm per minute and the contamination of mica and the sample is avoided. The resulting experimental force sensitivity is about 10 N. The force measurement is performed by progressively approaching or retracting the surfaces. When the equilibrium separation is reached, the piezo displacement and the transmitted wavelengths are recorded. A complete approach/retraction cycle takes typically 30 minutes. A review on the SFA technique can be found in [41]. 

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