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Graduate Theses & Dissertations

: Automated Separation and Preconcentration of Ultra-Trace Levels of Radionuclides in Complex Matrices by Online Ion Exchange Chromatography Coupled with Inductively Coupled Plasma Mass Spectrometry (ICP-MS); Radionuclides occur in the environment both naturally and artificially. Along with weapons testing and nuclear reactor operations, activities such as mining, fuel fabrication and fuel reprocessing are also major contributors to nuclear waste in the environment. In terms of nuclear safety, the concentration of radionuclides in nuclear waste must be monitored and reported before storage and/or discharge. Similarly, radionuclide waste from mining activities also contains radionuclides that need to be monitored. In addition, a knowledge of ongoing radionuclide concentrations is often required under certain ‘special’ conditions, for example in the area surrounding nuclear and mining operations, or when nuclear and other accidents occur. Thus, there is a huge demand for new methods that are suitable for continuously monitoring and rapidly analyzing radionuclide levels, especially in emergency situations. In this study, new automated analytical methods were successfully developed to measure ultra trace levels of single or multiple radionuclides in various environmental samples with the goal of faster analysis times and less analyst involvement while achieving detection limits suitable for typical environmental concentrations. Author Keywords: automation, ICP-MS, ion exchange, radionuclide

: Molecular Architectures for Improved Biomaterials Derived from Vegetable Oils – Application to Energy Storage and Lubricants; The replacement of petroleum with renewable feedstock for energy and materials has become a priority because of concerns over the environment and finite nature of petroleum. The structures of the available natural biomass feedstocks fall short in delivering key functionality required in materials such as lubricants and phase change energy storage materials (PCMs). The approach taken in this thesis was to combine select functional groups with vegetable oil derivatives to create novel PCMs and lubricantswhich deliver desired functionality. One series of diester PCMs were prepared with terephthalic acid and fatty alcohols to address known shortcomings of esters. The second class of PCMs are sulfones prepared from oxidation of fatty sulfides to improve thermal energy storage. Overall, the new PCMs presented narrow phase change temperature ranges, high transition temperature (between 67 to 110℃), high transition enthalpy (210 to 266J/g), minimal supercooling and congruent phase transitions unaffected by cooling rates. They also demonstrated higher thermal degradation stability with onset of degradation from 290 to 310℃. The series of lubricants studied consists of sulfide and sulfonyl functional groups attached to the unsaturation sites of oleyl oleate as pendant groups to improve the thermal and flow properties. The new lubricants present subzero crystallization temperatures, very low crystallization enthalpy and dynamic viscosity as high as 180mPas. Furthermore, they also presented high onset of degradation (up to 322℃) and oxidation (up to 298℃). The PCMs and lubricants of the present thesis demonstrate that select functional groups can be used with common structural elements of vegetable oil such as fatty acids, ester groups and unsaturation sites to make a variety of molecular structures capable of delivering desired properties Author Keywords: Crystal Structure, Lubricant, Phase Change Material, Renewable, Structure-Property Relationships, Vegetable Oil

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