A countercurrent, liquid-solids contactor was constructed,
operated and evaluated for a continuous ion-exchange operation.
The exchange of cupric and sodium ions between aqueous solutions
and Dowex 50W-X8 ion exchange resin was studied.
The countercurrent contactor consisted of two, three-inch
diameter columns with active sections ranging from one to four feet...
More efficient methods are needed for the in-situ evaluation of mass transfer parameters which describe the movement of solutes through aquifer material. The objective of this study was to develop a method for estimating diffusion rate and capacity coefficients using a single-well, "push-pull" tracer test. The method consists of the...
The continuation of geoarchaeological investigations at Tseriadun (35CU7) contributes to the understanding of the site's depositional history and the associated environments, thereby identifying the long term geomorphic change in the area and providing the environmental context for local human activity as it is reflected in the archaeological record. Meeting this...
The work presented here is focused on applying basic principles of solid-state chemistry to the study and development of new wide band-gap semiconductors and insulators for photovoltaic and electronic-device applications. Analysis of crystal structure, band structure, optical band gap, morphology and transport properties provides fundamental insight into materials performance as...
The Pelton Round Butte Hydroelectric Project (Oregon) was built between 1957 and 1964. As a result the anadromous steelhead trout was extirpated from the upper Deschutes Basin by 1968. The Deschutes Basin is a model for instream flow restoration projects in the Pacific Northwest that are largely driven by the...
Mycosphaerella graminicola (anamorph Septoria tritici) causes Septoria tritici blotch, a globally important disease of winter wheat. Resistance and pathogenicity generally vary quantitatively. The pathogen reproduces both sexually and asexually, and the pathogen population is highly genetically variable. Several unresolved questions about the epidemiology of this pathosystem are addressed by this...
Cooperative behaviors in bacteria are increasingly appreciated for their relevance to microbial ecology and utility as model systems for social evolution. One example is the secretion of siderophores, a structurally diverse group of compounds that chelate extracellular iron. Siderophore production is considered cooperative because the benefits can be shared with...
The main theme of this research is the application of geographic techniques in a study involving environmental monitoring and analysis of the associations between landscape and in-stream characteristics in the Pacific Northwest. The geographic techniques used in this study include (1) geographic information systems (GIS) coupled with statistical analysis and...
The objectives of this research were to 1) evaluate the establishment and peak standing crop of Berber Orchardgrass (Dactylis glomerata var. "Berber"), Palestine Orchardgrass (Dactylis glomerata var. "Palestine"), and Sheep Fescue (Festuca ovina var. "Covar") ; 2) to assess establishment and production changes resulting from environmental gradients (elevation, slope, aspect,...
River ecosystems throughout the arid southwestern U.S. are imperiled. Water management infrastructure, climate change, unsustainable water use, and political conflict harm the region's aquatic and riparian ecosystems. This case study surveys one such desert river, an endemic fish species, and conservation efforts in southwestern Utah. The analysis focuses on the...