Thesis (Ph. D.)--School of Earth and Atmospheric Sciences, Georgia Institute of Technology, 2004. Directed by Rong Fu. / Includes bibliographical references (leaves 119-131).

Thesis (Ph. D.)--University of Tennessee, Knoxville, 2004. / Title from title page screen (viewed May 14, 2004). Thesis advisors: Robert A. Bohm, Michael J. McKee. Document formatted into pages (xi, 185 p. : ill. (some color)). Vita. Includes bibliographical references (p. 116-122).

Thesis (M.S.)--Oregon State University, 2002. / Typescript (photocopy). Includes bibliographical references (leaves 62-64). Also available on the World Wide Web.

Thesis (M.S.) in Ecology and Environmental Sciences--University of Maine, 2002. / Includes vita. Bibliography: leaves 57-59.

Thesis (M.S.)--Ball State University, 2009. / Title from PDF t.p. (viewed on Feb. 08, 2010). Includes bibliographical references (p. 37-38).

Terrace deposits along a 40 mile segment of the Colorado River between Austin and Bastrop, Texas, are mapped in detail. The following deposits have been delineated (lowest to highest): Floodplain, Sixth Street Terrace, Montopolis Terrace, Capitol Terrace, Hornsby Terrace, Asylum Terrace, and Delaney Terrace. The Hornsby Terrace deposits and the Montopolis Terrace deposits were previously unrecognized. A program of mechanical analysis was conducted on samples taken from the terrace deposits and the floodplain. Cumulative frequency curves of grain size from five samples collected up to 15 miles apart from the Asylum Terrace gravel, are distinctively grouped--different from all other samples. Cumulative frequency curves from five samples from the Hornsby Terrace gravel also plot in a close grouping distinct from other samples. Over short distances where abrasion is not a dominant factor it seems that grain size distribution may be useful as a means of correlation of terrace remnants. Analysis of the lithologies of these samples indicate that the Hornsby, Asylum and Delaney Terrace gravels are practically without limestone clasts, in a drainage basin that is, presently, composed dominantly of limestone. This suggests that the Commanche Series in the Edwards Plateau region was not extensively exposed but was covered by the Gulf Series at the time of the formation of these terraces. The Manor lag gravel, an upland gravel in the thesis area, is thought to be the remnant of a high terrace deposit of the Colorado River. All terrace gravels except the Capitol and Montopolis Terrace gravels are thought to be the result of lateral planation by a stream at or near grade. The Montopolis and Capitol Terrace gravels are thought to be the result of a lengthy episode of lateral planation by the Colorado River accompanied by slow degradation. / text

River deltas are dynamic ecosystems of environmental, ecological, and societal importance. In coastal Louisiana, land loss and increased nutrient loading are altering the eco-geomorphic equilibrium, raising concern for the environmental concerns associated with climate and anthropogenic change. Over the last 100 years, nearly 5000 km2 of wetlands have been submerged due to a variety of environmental and anthropogenic forces. Wetland drowning and costal retreat is predicted to continue, threatening both human and environmental interests. As a result, mitigation efforts in the form of planned river diversions designed to build new land by natural delivering sediment to the once-leveed floodplains have been proposed. Denitrification in coastal wetlands has the potential to limit the risks of hypoxia and related eco-geomorphic issues by reducing the nitrogen export to receiving waters. The goal of this research project is to understand and quantify to propagation of environmental fluxes through a delta distributary system. Water fluxes in the delta distributary network are not solely propagated within the distributary channels and interdistributary areas, taking the form of inundated island interiors surrounded by subaerial levees, are hydrologically important. At Wax Lake Delta (WLD) in coastal Louisiana, roughly 50% of the flow is exchanged to the island swamps, suggesting that significant portions of nutrients are transported to the island interiors. The hydraulic residence times (HRTs) of the islands are estimated to be 15 – 29 hours and 11 – 18 hours on Mike and Pintail Islands, respectively; both being well below HRT estimates for significant denitrification. Spatial variability in network structure, specifically channel width and frequencies of confluences and bifurcations, influences the transport dynamics within the delta. However, flow partitioning in major distributary channels at WLD is relatively constant with time, supporting the hypothesis that network structure controls flux dynamics. / text

published_or_final_version / Applied Geosciences / Master / Master of Science

published_or_final_version / Industrial and Manufacturing Systems Engineering / Doctoral / Doctor of Philosophy

During the past decade, the high-speed rail (HSR) has got momentum in China, and a number of lines have been put into operation. However, it is noted that the HSR development in China is quite different from that in other regions. The discrepancies are mainly embodied in the duality of HSR types, the diversity of station locations, and the mixed-speed and cross-rail-type train running scheme. These characteristics have considerable impacts on the HSR stations in terms of the external accessibility in the HSR network as well as the internal accessibility in the cities. Based on the comparative study on the accessibility of main HSR stations in Yangtze River Delta, it is discovered that compared with the conventional rail (CR), the HSR has significantly improved the external accessibility of various cities. It is also found that the HSR has further enhanced the hub status of big cities in the rail network, while the differences among the other cities have been reduced, since the small cities have benefited much more from the HSR than the medium cities. Besides, introducing a new HSR line would improve the external accessibility of cities not only in the HSR network but also in the CR network, due to substantial increases in the efficiency of the whole rail system. In terms of the internal accessibility, it is found that the location choice of stations has significant impacts on the accessibility of HSR stations in cities, and the newly built stations have much lower accessibility due to their remote locations and the under-developed transport facilities and services connecting to them. Overall, for a complete journey by the HSR, the improvement in the external accessibility has made the internal accessibility of HSR stations more critical and sensitive. In this sense, more efforts should be paid to improve the urban transport system so as to fully utilize the positive effects brought about by the HSR. / published_or_final_version / Transport Policy and Planning / Master / Master of Arts in Transport Policy and Planning