Vacuum ultraviolet reflectivity measurements of three thin-film electroluminescent phosphors, zinc sulfide (ZnS), strontium sulfide (SrS), and strontium-calcium thiogallate (Sr₀.₄₅Ca₀.₅₅Ga₂S₄), are reported using thin-film samples. Measured ZnS reflectivity peak positions are in agreement with values previously reported in the literature. SrS room temperature reflectivity measurements are found to be consistent with...
We review several approaches that have been used to estimate ocean surface gravity wavenumbers from wave-resolving remotely sensed image sequences. Two fundamentally different approaches that utilize these data exist. A power spectral density approach identifies wavenumbers where image intensity variance is maximized. Alternatively, a cross-spectral correlation approach identifies wavenumbers where...
Sandbars are ubiquitous, yet not well understood
beach features that change their position and shape in
response to changing wave conditions. We propose and test
a simple empirical model consisting of two coupled linear
differential equations that represents bar dynamics in terms
of wave forcing and two other state variables:...
Plantation forests on mountainous areas in Tanzania, East Africa, were successfully
established in the 1950's. Harvesting started in the 1970's to meet increased national
timber demand. Current problems of unharvested areas and potential environmental
degradation are associated with uncontrolled harvests, mismatch of harvest systems to
site needs, and post-harvest practices....
The temporal and spatial variability of crescentic sandbars is analyzed with hourly
long-term (months) video observations collected at four barred sites and are qualitatively
compared to the temporal and spatial variability predicted by hypotheses underpinning
existing approaches and models for crescentic bar formation (edge-wave template model,
linear stability analysis, and...
Lagrangian particle tracking (LPT) models are used to explore how physical processes influence the transport of particles (e.g., eggs, larvae, or propagules) in the ocean. On the Oregon continental shelf and slope, the Northern California Current System (CCS) is influenced by spatially and temporally variable coastal currents driven by weather,...