This research concerns the effects on samples of nominal composition Bil.8Pb0.2Sr2Ca2cu30y which were exposed to hot, dense argon in a ballistic compressor. The investigations were concentrated on two specimens which were exposed to hot, dense argon at about 1800 K (peak pressure 330 atm) and 1500 K (peak pressure 230 atm), respectively. Sample Bi #1 showed a completely melted surface structure after triple exposure in the ballistic compressor at 1800 K while the surface of sample Bi #7 was just partly melted after double exposure at 1500 K. Changes in flux trapping capability and qualitative Meissner effect were investigated in addition to the properties described by Duan, et al. ( 17, 18, 3 2] , who reported changes in critical temperature, crystal structure, surface morphology and composition after exposure of samples to hot, dense argon. After triple exposure in the ballistic compressor at a temperature of approximately 1800 K, sample Bi #1 showed an enhanced Meissner effect on the exposed side compared to the unexposed side of the pellet, while no difference in Meissner effect was found between the exposed and the unexposed side of sample Bi #7. EDS analysis showed that both samples are inhomogeneous in chemical surface composition. Oxygen loss due to exposure to hot, dense argon could not be demonstrated. X-ray analysis indicated that the melted surface layer of sample Bi # 1 after triple exposure to hot, dense argon contains smaller crystals than before exposure in the ballistic compressor. Tc measurements gave varying results which are explainable by the chemical inhomogeneity of the specimens. An increase in the amount of trapped flux due to exposure of the samples to hot, dense argon could not be demonstrated

The effect of moisture absorption on the glass transition temperature (Tg) and stress/strain behavior of network polyurethane shape memory polymer (SMP) foams has been investigated. With our ultimate goal of engineering polyurethane SMP foams for use in blood contacting environments, we have investigated the effects of moisture exposure on the physical properties of polyurethane foams. To our best knowledge, this study is the first to investigate the effects of moisture absorption at varying humidity levels (non-immersion and immersion) on the physical properties of polyurethane SMP foams. The SMP foams were exposed to differing humidity levels for varying lengths of time, and they exhibited a maximum water uptake of 8.0 percent (by mass) after exposure to 100 percent relative humidity for 96 h. Differential scanning calorimetry results demonstrated that water absorption significantly decreased the Tg of the foam, with a maximum water uptake shifting the Tg from 67 °C to 5 °C. Samples that were immersed in water for 96 h and immediately subjected to tensile testing exhibited 100 percent increases in failure strains and 500 percent decreases in failure stresses; however, in all cases of time and humidity exposure, the plasticization effect was reversible upon placing moisture-saturated samples in 40 percent humidity environments for 24 h.

Thesis (Ph. D.)--University of Alabama at Birmingham, 2007. / Title from PDF title page (viewed Jan. 28, 2010). Additional advisors: Derrick R. Dean, Wiliam K. Nonidez, Andrei Stanishevsky, Charles L. Watkins. Includes bibliographical references.

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Dynamical heterogeneity (DH) has been observed in many systems approaching the glass or jamming transition. Whether DH has a structural origin is under heated debate. To provide a deeper understanding, in this thesis I investigate the microscopic dynamics in weakly attractive colloidal systems by confocal fluorescence microscopy. The van Hove density-density correlation function is applied to our systems. Separable fast and slow populations emerge in the self part (svH), while the distinct part shows a strong signature of DH close to the gel transition. At intermediate time, svH shows a purely exponential tail, mainly arising from the fast population. I show that this broad tail is a direct consequence of the occurrence of rare large jumps that are statistically distributed. The slow population tends to form a space-spanning backbone, and its mean squared displacement close to the gel transition exhibits a plateau, whose height is consistent with the range of attraction, suggesting a bonding mechanism for the dynamical arrest. I further examine various quantities characterizing local structure and local dynamics and a strong correlation is identified between them. Subsequently, I develop order parameters for quantifying amorphous structure and apply them to our systems. I find that attractive colloidal systems exhibit higher order under higher attraction tension, while hard spheres become more ordered under higher compression. Finally, I investigate the effect of the range of attraction on the structure and dynamics of attractive colloidal systems. I observe that the system with shorter range of attraction forms a denser and more heterogeneous structure. Meanwhile, I observe an even stronger dynamical heterogeneity. These observations provide further evidence of a connection between structural heterogeneity and dynamical heterogeneity in these systems, providing guidance for a theoretical description of the dynamical arrest as well as the relaxation mechanisms upon gelation and its relation to solidification in glasses. / In order to do all of this, I first implemented full 3D subpixel resolution localization of particles and improved particle tracking algorithms tailored for the sorts of heterogenous dynamics these systems exhibit, that otherwise confounds existing methods such that the very relaxation mechanisms would be missed. This allows us to obtain unprecedented precision in positions of all of the particles and complete tracking, both of which are essential for correctly determining system properties that depend on measured particle dynamics.

Thesis (M.Eng.)--University of Wollongong, 2005. / Typescript. Includes bibliographical references: leaf 113-121.

Thesis (Ph.D.)--Materials Science and Engineering, Georgia Institute of Technology, 2008. / Committee Chair: Speyer, Robert; Committee Member: Gerhardt, Rosario; Committee Member: Liu, Meilin; Committee Member: Lynch, Christopher; Committee Member: Wilkinson, Angus

Thesis (Ph. D.)--University of Missouri-Columbia, 1998. / Typescript. Vita. Includes bibliographical references (leaves 139-150). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 1998. / Typescript. Vita. Includes bibliographical references (leaves 139-150). Also available on the Internet.

Thesis (Ph.D.)--Hong Kong University of Science and Technology, 2004. / Includes bibliographical references. Also available in electronic version.