Physical Sciences and Mathematics Commons^™

Pupil Phase Apodization For Achromatic Imaging Of Extra-Solar Planets, Weidong Yang

Dissertations, Master's Theses and Master's Reports - Open

Direct imaging of extra-solar planets in the visible and infrared region has generated great interest among scientists and the general public as well. However, this is a challenging problem. Diffculties of detecting a planet (faint source) are caused, mostly, by two factors: sidelobes caused by starlight diffraction from the edge of the pupil and the randomly scattered starlight caused by the phase errors from the imperfections in the optical system. While the latter diffculty can be corrected by high density active deformable mirrors with advanced phase sensing and control technology, the optimized strategy for suppressing the diffraction sidelobes is still …

Application Of Well Log Tomography To The Dundee And Rogers City Limestones, Michigan Basin, Usa, Mellisa A. Le M.

Dissertations, Master's Theses and Master's Reports - Open

The Michigan Basin is located in the upper Midwest region of the United States and is centered geographically over the Lower Peninsula of Michigan. It is filled primarily with Paleozoic carbonates and clastics, overlying Precambrian basement rocks and covered by Pleistocene glacial drift. In Michigan, more than 46,000 wells have been drilled in the basin, many producing significant quantities of oil and gas since the 1920s in addition to providing a wealth of data for subsurface visualization.

Well log tomography, formerly log-curve amplitude slicing, is a visualization method recently developed at Michigan Technological University to correlate subsurface data by utilizing …

Hydrogeochemical Controls On Uranium In Aquifers Of The Jacobsville Sandstone, Heidi M. Sherman

Dissertations, Master's Theses and Master's Reports - Open

The occurrence of elevated uranium (U) in sandstone aquifers was investigated in the Upper Peninsula of Michigan, focusing on aquifers of the Jacobsville Sandstone. The hydrogeochemical controls on groundwater U concentrations were characterized using a combination of water sampling and spectral gamma-ray logging of sandstone cliffs and residential water wells. ²³⁵U/²³⁸U isotope ratios were consistent with naturally occurring U. Approximately 25% of the 270 wells tested had U concentrations above the U.S. Environmental Protection Agency Maximum Contaminant Level (MCL) of 30 μg/L, with elevated U generally occurring in localized clusters. Water wells were logged to determine whether …