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In this thesis, molecular dynamics simulations were performed to characterize the atomic motions governing grain boundary migration in a series of [001] twist boundaries. Particularly, migrations of a =36.87 5, a =22.63 13 and a =40.23 general high angle [001] twist boundaries driven by stored elastic energy in fcc Ni were investigated. Atomic motions during migration were identified as the combination of single atom jump and string-like cooperative atomic motions. The simulation results confirmed that the collective 4-atom shuffle motion was the rate controlling atomic motion during the migration of 5 twist boundary. As grain boundary local symmetry decreasing, string-like cooperative atomic motions became increasingly important. Eventually, both random single atom jump and string-like cooperative motions became dominant during the migration of general non- twist boundary. Furthermore, simulations showed that activation energy for grain boundary migration was well correlated with the average string length occurring within boundary. / Materials Engineering

Graduation date: 2000

The aim of this study is to compare observational data to data simulated by a one dimensional model. Observational data collected from January to July 2006 at Lake Whitney, Texas, included water current velocities from an Acoustic Doppler Current Profiler, and an Acoustic Doppler Velocimeter from which shear stress, turbulent kinetic energy dissipation rates, and turbulence kinetic energy were computed using several methods. Numerical model experiments, forced by the surface heat and momentum fluxes, velocity profiles, and temperature profiles were conducted to simulate the development of the turbulence parameters. Two equation models, k-epsilon and k-kl, were used to find which model best describes the observed physical processes (turbulence kinetic energy, turbulent kinetic energy dissipation rate and velocity variances). The combined observational and simulated results show a change in stratification levels that consequently leads to variations in turbulent kinetic energy dissipation rate, turbulent kinetic energy, and the velocity variances. In order to investigate the accuracy of the model, we quantitatively compared these parameters to estimates from the observed data in the bottom boundary layer. In general, the model and observational data agree well for the three parameters, with the exception of some time periods, during which the model prediction differed from the observed. This was at times when the Acoustic Doppler Velocimeter measurements were at the noise level of the instrument. Overall, the k-kl model simulation results appear to be closer to the observational results during the weakly and strongly stratified periods than the k-epsilon model.

Thesis (PhDApSc(MineralsandMaterials))--University of South Australia, 2007.

Typescript (Photocopy) / Bibliography: leaf 75 / 75 leaves ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Pure Mathematics, 1985?

iv, 135 leaves : tables, graphs ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--Dept. of Applied Mathematics, University of Adelaide, 1979

The fragmentation of administrative boundaries is a serious problem in the analysis of social, environmental and economic data. This research focuses on the development of a coordinated approach to the design of administrative boundaries that endeavours to support accurate decision making. Around the world, administrative boundaries have been structured in an uncoordinated manner, limiting data exchange and integration between organisations. The solution proposed in this research adopts the hierarchical reorganisation of administrative boundaries to enhance data integration and data exchange within the spatial data infrastructure (SDI) framework.The SDI is an initiative intended to facilitate access to complete and consistent data sets. One of the most fundamental problems restricting the objectives of the SDI is the fragmentation of data between non-coterminous boundary systems. The majority of administrative boundaries have been constructed by individual agencies to meet individual needs. Examples of the proliferation of different boundary systems include postcodes, census-collector districts, health districts and police districts. Due to the lack of coordination between boundary systems, current technologies for analysing spatial data, such as geographic information systems (GIS), are not reaching their full potential. A review of the current literature reveals that, until now, little has been done to solve this problem.The prototype developed within this research provides a new mechanism for the design of administrative boundaries. The prototype incorporates two algorithms. These are based on HSR theory and administrative-agency constraints and are implemented within the GIS environment. Such an approach is an example of the potential that is available when we link spatial information theory with the SDI framework and disciplinary knowledge.

This thesis documents an extensive experimental investigation into low-Reynolds-number turbulent boundary layers flowing over a smooth flat surface in nominally zero pressure gradients. The way in which these layers are affected by variations in R(theta), i.e. the Reynolds number based on the boundary-layer momentum thickness, type of tripping device used and variations in freestream velocity, each considered independently, are investigated.

Thesis (M.S.)--University of Toledo, 2007. / Typescript. "Submitted as partial fulfillments of the requirements for the Master of Science Degree in Mechanical Engineering." "A thesis entitled"--at head of title. Bibliography: leaves 196-205.