Paul Dunn

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Coupling between the lower and upper atmosphere, combined with loss of gas from the upper atmosphere to space, likely contributed to the thin, cold, dry atmosphere of modern Mars. To help understand ongoing ion loss to space, the Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft made comprehensive measurements of the Mars upper atmosphere,(More)
The Mars Atmosphere and Volatile Evolution (MAVEN) mission, during the second of its Deep Dip campaigns, made comprehensive measurements of martian thermosphere and ionosphere composition, structure, and variability at altitudes down to ~130 kilometers in the subsolar region. This altitude range contains the diffusively separated upper atmosphere just above(More)
of the Forest Fire Laboratory. In addition we thank the "old timers" Morris McCutchan and Lisle R. Green, both retired from the Forest Fire Laboratory, for their technical reviews and historical knowledge. The research covered by this paper would not have been possible without excellent cooperation by many agency, industry, and university personnel. Recent(More)
The weathering of parent rock may be an important source of some nutrients. The rates of weathering of the different parent rock materials vary and affect the inherent fertility and productivity of a site. Little is known about the nutrient additions to southern California soils by rock weathering although some research on granitic soils in Idaho indicates(More)
A BSTRACT. Seedlings of ponderosa pine, Douglas-fir, white fir, Engelmann spruce, and subalpine fir were exposed continuously to charcoal-filtered (CF) air or one of three levels of a simulated ambient exposure typical of SO, pollution near smelters in the western United States. Seedlings were exposed during winter-spring experiments for 60 days to hourly(More)
The original version of this Article contained an error in the spelling of a member of the University of Michigan students Consortium, Sam Lee, which was incorrectly given as Sam Lewe. This has now been corrected in both the PDF and HTML versions of the Article. This work is licensed under a Creative Commons Attribution 4.0 International License. The images(More)
The vacuum system of System C has been modified in order to obtain a lower base pressure and to reduce wall outgassing by the plasma. A 400-liter/sec VacIon pump was installed in place of the oil diffusion pump. All of the large O-ring seals were replaced by copper gaskets and Conflat flanges, and the remaining O-rings were replaced by Viton O-rings. A(More)
A. BEAM-PLASMA DISCHARGES 1. THE KITZELTRON From our beam-plasma discharge experiments we have discovered the following important characteristics: (i) Nearly 100 per cent ionization. When we fire a 10-kv, 10-amp electron beam into a hydrogen atmosphere 2 X 10-5 torr (-6 X 1011 mol/cc) a plasma density of approximately 1013/cc is created. This indicates that(More)
The purpose of this study is to determine whether there are cross-cultural differences between Chinese and Canadian business students with respect to their assessment of the ethicality of various business behaviours. Using a sample of business students, the results indicate cultural divergence; the Chinese and Canadians exhibit different ethical attitudes(More)