Thesis (Ph.D.)--University of Melbourne, The School of Chemistry, 2010. / Typescript. Includes bibliographical references.

Thesis (M. Phil.)--University of Hong Kong, 2010. / Includes bibliographical references (leaves 139-[147]). Also available online.

Thesis (Ph. D.)--University of Missouri-Columbia, 2007. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on September 4, 2007) Vita. Includes bibliographical references.

Report (M.S.)--Virginia Polytechnic Institute and State University, 1994. / Vita. Abstract. Includes bibliographical references (leaf 130). Also available via the Internet.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Meteorology and Physical Oceanography, 1982. / Microfiche copy available in Archives and Science / Bibliography: leaves 194-196. / by Joshua Michael Aaron Ryder Wurman. / M.S.

Thesis (M.S.)--Oregon State University, 2009. / Printout. Includes bibliographical references (leaves 52-54). Also available on the World Wide Web.

A gas-diffusion tracer experiment was conducted at the ChemNuclear, Inc., nuclear waste burial site near Barnwell, South Carolina, on June 1-10; 1981, testing a new methodology to measure the in situ gaseous diffusion characteristics of unsaturated porous media for the purpose of estimating the diffusive flux of volatile contaminants from the burial ground. The tracers used were CClBrF₂ and SF₆. They were released in the subsurface from permeation devices that closely approximate an ideal point-diffusion source. The permeation devices contain the tracer in liquid form and allow the tracer to escape at a constant rate by diffusion through a Teflon membrane. The release rates for CClBrF₂ and SF6 during the test were 105 and 3.3 nanograms/second, respectively. These compounds were selected on the basis of their compatabi1ity with the permeation-release device, their absence in the subsurface, and detectability in the part-per-tri11ion range in soil gas. Analyses were made in the field on a Varian 3700 series gas chromatograph equipped with an electron-capture detector. The instrument was modified to introduce soil gas through sampling valves and a Nafion tube desiccant. The diffusion sources were placed in the unsaturated soil at depths of 2 meters and 13 meters below land surface. Diffusive movements of tracer were monitored for a period of 7 days and tracer breakthrough was observed at points up to 3.5 meters away. Diffusion was modeled using a three-dimensional, continuous point source, transient-state, analytical model which allowed estimation of the effective diffusion coefficient of the porous media, and an independent assessment of the media's sorptive effects on the tracer gas. The model was calibrated using least squares and curve matching techniques, the latter of which enables a field technician to quickly interpret observed field data. Field values obtained for effective diffusion coefficient ranged from 0.026 to 0.037 cm²/sec. The average tortuosity factor observed for test site was 0.705.

The human health effects of acute exposure to high levels of ionizing radiation are well understood; however, when these irradiations occur at low levels, there is controversy as to their potential health threat (BEIR V, 1990). For individuals living in areas where the level of naturally occurring background radiation is relatively high, the issue of additional exposure to anthropogenically derived sources of ionizing radiation may be of some concern. This study investigates the presence of radionuclides in surface soils near a United States Environmental Protection Agency (EPA) Superfund site near Pocatello, Idaho, where two phosphorus production facilities have operated for more than fifty years. It is hypothesized that airborne particulates from these facilities are migrating into a residential community, and are accumulating in the uppermost soil layers. Soil samples were collected from seven sites located between 1.3 and 6.7 km along a transect aligned with the prevailing downwind direction. The transect origin lies at the northern boundary of the Superfund site, and the sites were selected for their ease of public access. Samples were collected at four different 2.5 cm depths (10 cm total) for each site, and these samples were analyzed for their gamma emissions. Statistical evaluations of the sample data yielded results of no significant difference in nuclide concentrations between soil layers, or between sample sites (��=0.05). This investigation corroborates the EPA discovery that nuclide concentrations in surface soils decrease rapidly beyond 1 km from the site boundary. This study extends the available information regarding the presence of radionuclides in off-site surface soils by approximately 4 km in the prevailing downwind direction. Additionally, these data appear to contradict the EPA's conclusion that no residential exposure is occurring via a surface soil pathway. This investigation finds that surface soil exposures, at locations such as public parks and schools, may be occurring from radionuclide concentrations that are as high as 4 times that of published background radiation levels. / Graduation date: 2002

The objective of this research was to estimate the radiological impact on various non-human biotas by the Fukushima Daiichi Nuclear power plant radiation release resulting from Japan's tsunami in March 2011 consistent with the recent recommendations of the International Commission on Radiological Protection. Soil concentration data given by Japan's Ministry of Education, Culture, Sports, Science and Technology in Japan (MEXT) were used to approximate doses to various organisms. Cumulative doses and dose rates were plotted in ArcGIS 10, geographic information system (GIS) software, and Kriging interpolations were performed between the sampling points. The conclusion of this preliminary investigation that there appears to be the potential for adverse biological impacts of the studied biota; however, the magnitude of the impact will require further investigation. / Graduation date: 2013

The Teledyne Wah Chang facility is a manufacturer of the rare metal zirconium. The facility has been in constant production since 1956. In 1973 an attempt to utilize different sand ore sources from Nigeria and India in a new carbiding process, prior to chlorination, failed. The resulting byproducts of the carbiding process and approximately 2000 kg of zircon sand ore were lost in what is now called the Former Sand Unloading Area. In 1982, Teledyne Wah Chang facility was listed as a Superfund site. The Former Sand Unloading Area was contaminated with naturally-occurring radioactive material. After being listed, Teledyne Wah Change began the Remedial Investigation / Feasibility Study process in an attempt to cleanup the Former Sand Unloading Area and other contaminated sites. Afterwards, it was discovered that the remediation goals for the Former Sand Unloading Area only addressed exposure pathways to current workers on site. No consideration had been given to possible future occupants under long term exposure scenarios. In this study, three scenarios were modeled to illustrate the most plausible occupancy uses of the Former Sand Unloading Area. The scenarios were: current industrial worker, commercial worker, and a residential occupant. The pathways that were used to model the exposure scenarios were, direct external radiation, inhaled and ingested soil, and plant consumption. The RESRAD computer code was used to estimate the dose rates to current and future occupants working or living on the Former Sand Unloading Facility. The maximum resulting radiation dose received was 16.7 mrem y����� for the industrial worker scenario. The lowest maximum radiation dose received was 13.6 mrem y����� for the commercial worker scenario. The most conservative assumptions and efforts were used to ensure the maximum dose rate was modeled. The maximum radiation dose rate received at the Former Sand Unloading Area was below the regulatory maximum allowable exposure limit of 25 mrem y�����. / Graduation date: 2002