xii, 64 p. : ill. (some col.), maps / Salmon habitat restoration is ongoing at a Nature Conservancy preserve on the Middle Fork John Day River in the Columbia River Basin in north-central Oregon. The site has a long history of disturbance including dredge mining upstream, channelization, grazing, logging, fire, and floods. Using historic aerial photos, habitat unit surveys, and cross sectional profiles, this thesis shows how the channel morphology, particularly habitat unit diversity, has changed since 1939, just before placer mining began. Results show that the dominant influence on present day channel morphology is channelization from the 1930's. Other changes including dredge mining in the late 1930's to early 1940's, cessation of cattle grazing in 1991, and a fire followed by a flood in the winter of 1996-1997, had less impact because of the straightened, stabilized channel morphology. / Committee in charge: Patricia McDowell, Chairperson; W. Andrew Marcus, Member / 10000-01-01

The anatomy of bifurcations in trees requires further scientific investigation as the current anatomical model for them is logically flawed. The provision of a better model will assist in scientific studies of woody plants, the risk assessment of junctions in mature trees and provide bio-inspiration for Y-shaped joints in composite materials. In this study, the xylem formed in the central axis of a hazel (Corylus avellana L.) bifurcation is shown to provide a disproportionately greater amount of its tensile strength. CT scanning identified that this centrally-placed xylem was 28.1% denser, with 63% less vessels formed in this tissue, such vessels being 50.5% of the diameter and 32.5% of the length of those formed in adjacent stem tissues. The wood grain pattern at the bifurcation apices were 22 times more tortuous, forming interlocking patterns that acted to resist tensile forces by requiring the extraction or breaking of wood fibres along their length (the axial tensile strength of wood). Subsequent tests confirmed that this conferred more than 100% additional tensile strength to these specialised xylem tissues. These findings provided the basis of a novel anatomical model for bifurcations in woody plants. Further to this, the effects of several factors upon junction strength and biomechanical behaviour were assessed in bifurcations of hazel, identifying the weakening effect of bark inclusions and three types of artificial modification as well as differences in wind-induced movement between bifurcation types. This study concludes that further investigations of bifurcations in a wider range of woody plants and observations of the developmental stages of the interlocking wood grain patterns found at bifurcations would usefully add to existing knowledge.

This diploma thesis deals with design features of a customs swivel cabin fork-lift truck. Concept is adapted to the technical and ergonomic requirements and the main goal of this concept is to provide original design with a view to the future. The complex concept meets the operational, technical and ergonomic demands of such engines. The project is focused on the design concept and complex contour-composition of the swivel cabin fork-lift truck. Designed of the fork-lift truck stems from the modern technological methods and the construction is ready for production and everyday operating usage, hence the production of this project would be rather expensive for the local market. However, it might be possible to start the production of this fork-lift truck, equipped by various functional components, sometime in the future and such extra functional components will be included as basic accessories of any fork-lift truck.

Two areas along the Blacksmith Fork River, in the Bear River Range southeast of Logan, Utah, were studied as sites for a storage dam and reservoir. An earth dam, 150-200 feet high, and a reservoir of 15,000-20,000 acre-feet are contemplated by the Bureau of Reclamation, U.S. Department of Interior. The lower area, located about 7 miles east of the mountain front, involves two possible dam sites on limestone. Thick overburden is present in the canyon bottom and on the right abutments. The upper area, located about 2 miles south of the headquarters of the Hardware Ranch, includes two possible dam sites on quartzite. The quartzite at the upstream site was found, by drilling and testing, to be extensively fractured; the downstream site has not been drilled. Acceptable topographic settings are present at both of these sites. Geological factors, as well as a difficult road relocation necessitated by the reservoir, exclude the lower area. It is recommended that the downstream site of the upper area be explored by means of a drilling program. A systematic evaluation of constructio materials near this site, based on appropriate excavations, is also required. (58 pages)

Published detrital zircon geochronological data was compiled to form the Global Detrital Zircon Database (GDZDb). This database provides a reference block for provenance analysis by future detrital zircon geochronological studies. This project entailed three subprojects: 1. crustal growth/crustal recycling patterns, 2. a provenance study of the Triassic Dry Fork Formation of the Danville-Dan River Rift basin of Virginia and North Carolina, and 3. sample size issues in detrital zircon studies. The global detrital zircon age frequency distribution exhibits six prominent, statistically significant peaks: 3.2-3.0, 2.7-2.5, 2.0-1.7, 1.2-1.0, 0.7-0.5, and 0.3-0.1 Ga. These peaks are also observed when the data is sorted for continent of origin, the tectonic setting of the host sediment and for modern river sediments. Hf isotope model ages were also incorporated into the database where grains were dated with both U-Pb and Hf isotopes. The Hf isotope model ages suggest that the majority of detrital zircons U-Pb ages reflect crustal recycling events that generated granitic magmatism, as most grains exhibited Hf isotope ages that are much older than the corresponding U-Pb age. The Triassic Dry Fork Formation was sampled from a site in southern Virginia in the Danville-Dan River Basin. The detrital zircon age frequency distribution for this formation was strongly unimodal with a peak at 400-450 Ma and a paucity of Grenville-age zircons. Comparison of the Dry Fork sample to published east coast data and to the North American record (from the GDZDb) illustrate the unusual nature of the Dry Fork Formation sample. It is probable that older Grenville zircons were blocked from the rift valley by the rift shoulder. Using the GDZDb a study of sample size was conducted in order to estimate the best sample size to use when trying to constrain the maximum age of sedimentation of the host sediment. Rift basins and active margins exhibited smaller offsets from the youngest zircon grain age to host sediment maximum age than observed in samples from passive margins. This study recommends that at least 50 grains need to be age dated on average in order to best constrain the age of the host sediment. / Ph. D.

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