The measurement of high temperatures in oxides and oxide-based structures in practical applications often presents challenges including steep thermal gradients, the presence of flames or chemically aggressive environments, and the transparency or translucency of most oxides. For turbine engines, oxide coatings are of great commercial importance, and the rapid motion of parts prohibits contact thermometry. Luminescence thermometry offers a number of advantages for measuring temperature in such systems and has been the subject of ongoing study for many years. Recent work on rareearth-doped thermal barrier coatings, environmental barrier coatings, and related oxides has demonstrated the feasibility of luminescence thermometry to temperatures well in excess of 1000 • C. The luminescent properties of these materials and the analytical techniques used to extract reproducible temperature measurements from the measured luminescence are reviewed. 325 Annu. Rev. Mater. Res. 2009.39:325-359. Downloaded from www.annualreviews.org by University of Wisconsin -Madison on 09/25/12. For personal use only.

No abstract

No abstract

The goal of this study was to develop a 50-year statistical climatology of snowfall occurrences using data from a dense network of cooperative station observations covering northwest and central Missouri, and these records were provided by the Missouri Climate Center.This included a study of the long term trends and interannual variability in snowfall occurrence as related to sea surface temperature variations in the Pacific Ocean basin associated with the El Nin o and Southern Oscillation (ENSO) and the North Pacific Oscillation (NPO). These trends and variations were then related to four synoptic-scale flow regimes that produce these snowfalls in the Midwest. The results demonstrate that during the snowfall season (Oct -April) the northwest Missouri region can expect about eight snowfall events which produce three or more inches of accumulation. While no significant long-term trend in overall snowfall occurrence was found, a decrease in the number of extreme events (10 or more inches) was noted. Also, fewer snowfall events were found during El Nin o years, while more heavy snowfall events occurred during "neutral" years, and these results could be related to synoptic-scale variability. A closer examination of the results demonstrated that El Nin o/La Nin a related variability in snowfall occurrence was superimposed on longer-term NPO-related variability. [Interannual Variability, snowfalls, climatology, El Nin o]

No abstract