This dissertation investigates the dynamics of the tidally modulated outflow from the Columbia River mouth using high resolution measurements of velocity, density and turbulent microstructure. At high tide, flow through the river mouth reverses from flood (onshore) to ebb (offshore). During ebb, buoyant fluid issues from the river mouth and...
Time‐dependent buoyant plumes form at the outflow of tidally dominated estuaries. When estuary discharge velocity exceeds plume internal wave speed c, a sharp front forms at the plume’s leading edge that expands from the time‐dependent source. Using observations of the Columbia River tidal plume from multiple tidal cycles we characterize...
Turbulence controls the composition of river plumes through mixing and alters the plume's trajectory by diffusing its momentum. While believed to play a crucial role in decelerating river-source waters, the turbulence stress in a near-field river plume has not previously been observationally quantified. In this study, finely resolved density, velocity,...
The initial composition of a river plume depends on the cumulative turbulent
entrainment within the estuary and how this dilutes the supplied freshwater. Here we
examine the relative roles of turbulence and freshwater input using observations from the
Columbia River estuary and plume during two periods with contrasting river flow....
Measurements of suspended sediment concentration, velocity, salinity, and turbulent
microscale shear in the near-field region of the Columbia River plume are used to investigate
the mechanisms of sediment resuspension and entrainment into the plume. An east-west
transect was occupied during spring and neap tide periods in August 2005 and May...
Varied observations over Oregon’s continental shelf illustrate the
beauty and complexity of geophysical flows in coastal waters. Rapid, creative, and
sometimes fortuitous sampling from ships and moorings has allowed detailed looks
at boundary layer processes, internal waves (some extremely nonlinear), and coastal
currents, including how they interact. These processes drive...
Twelve days of microstructure measurements at the equator (140°W) in November 1984 showed a
surprisingly strong effect of both daily cycle of solar heating and wind on mixing in the upper ocean.
Because of limited variations in atmospheric forcing and currents during the experiment, processes in the
daily mixing cycle...
A method has been developed to measure the thickness of ZnS thin films on Si using optical interference. Thin film optical interference fringes are dependent upon the thickness of the film, and for this reason the thickness can be determined by measuring reflectance spectrum of a thin film. A grating...
Zinc tin oxide (ZTO) films deposited by pulsed laser deposition (PLD) are
investigated as a channel layers for transparent thin-film transistors (TTFTs).
Films are deposited on glass for characterization, and transistor channel layers are
deposited onto aluminum oxide-titanium oxide/tin doped indium oxide/glass
substrates (ATO/ITO/glass) to produce TTFTs.
UV-visible spectroscopy on...
Bulk properties of CuSc₁₋ₓMgₓO₂, CuSc₁₋ₓMgₓO₂₊y, BaCu₂S₂, Bai₁₋ₓKCu₂S₂, BaCu₂Se₂
and Bai₁₋ₓKₓCu₂Se₂ are investigated supporting the search for highly conductive p-type
thin films. Mg is an efficient dopant in CuScO₂ with conductivity up to l.5.10⁻² S/cm.
Oxidation of CuScO₂:Mg leads to further increase in conductivity up to 0.5 S/cm. The
amount of...