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Please read the abstract in the section, 00front, of this document Please note that the Compact disc with Vehsim2d (demonstration version) (Appendix B) is not included / Thesis (PhD (Mechanical Engineering))--University of Pretoria, 2008. / Mechanical and Aeronautical Engineering / unrestricted

Call number: LD2668 .T4 1965 C53 / Master of Science

This is a collection of creative nonfiction essays.

A research report submitted in partial fulfilment of the requirements for a Masters Degree in Environmental Sciences, School of Animal, Plant and Environmental Sciences. University of the Witwatersrand. Johannesburg, 2016. / Wetland ecosystems cover approximately 6% of the Earth’s surface area and provide important ecosystems goods and services for the sustenance of human livelihoods. According to the Millennium Ecosystems Assessment, wetlands’ ecosystems goods and services cover the provisioning, regulating, support of biodiversity, and wider community cultural values. However, wetland ecosystems are threatened by human interference in combination with effects of climate change, both of which might compromise the functionality of these socio-ecological systems. The study used a combination of observations, interviews and remote sensing combined with GIS to investigate evidence of change and the possible effects on the Blesbokspruit wetland’s natural integrity, and thus availability of ecosystem goods and services in the wetland. Documented spatial changes in land uses were analysed to determine the extent to which land use and cover changes have affected the natural capital (i.e. ecosystem goods and services) for people. The interaction of local people with the wetland was assessed in order to establish how they use the wetland as a livelihood support system. The study found that people from the surrounding communities both in the upper (Putfontein) and lower catchments (Marievale) are interacting with the wetland in different ways. The provisioning services from the Blesbokspruit wetland to the surrounding communities include water used for both domestic and agricultural activities. Both subsistence and commercial farming are taking place along the wetland (crop farming and livestock rearing). The wetland is therefore providing a safety net to disadvantaged households who are able to supplement their food. The wetland is also able to regulate climate change (carbon sequestration and flood attenuation) and water quality due to the presence of vegetation. The wetland also supports high biodiversity (flora and fauna) such as within the Marievale Bird sanctuary. Recreational services of the wetland come from the scenic views noted at both Marievale (picnic spots) and Putfontein (evidenced by children playing and swimming). The integrity of the wetland is primarily threatened by population increase and urbanisation. Remote sensing analyses of land use/land cover patterns between 1998 and 2015 indicate that major changes of the wetland have been due to human encroachment. Subsistence agriculture in the wetland has increased, which fuels damage to the wetland. Direct observation and interviews with female farmers showed that they compete for plot size which is proportional to the respect one farmer earns in the community. Water quality of the wetland seemed to be compromised by industrial activities and use of fertilisers by farmers. Unlike the pristine upper part of the wetland at Putfontein, eutrophication downstream was evidenced by polluted water, algal blooms and change of water colour at Marievale – all suggesting loss of natural benefits such as high quality water. Despite the observed threats, it is concluded that the Blesbokspruit wetland ecosystem goods and services play a significant role in supporting the well-being and livelihoods of surrounding poor communities. It is suggested that activities threatening the wetland’s integrity may be managed effectively through community-based approaches for natural resource management. There is a need for all stakeholders to be equipped with proper conservation knowledge for them to appreciate the indirect (e.g. climate regulation and water quality control) as well as direct (agricultural and water provisioning) benefits of Blesbokspruit wetland. A better understanding of this socio-ecological system would benefit from comprehensive research on hydrological dynamics associated with agricultural practices within the catchment, and the development of an integrated model of natural resources management with a strong social component. / LG2017

Ko, Pui Hang. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 86-90). / Abstracts in English and Chinese. / Chapter 1. --- Introduction --- p.1 / Chapter 1.1 --- Micro bearing in precision engineering --- p.1 / Chapter 1.2 --- Micro spiral spring --- p.5 / Chapter 1.3 --- Outline of the thesis --- p.9 / Chapter 2. --- Mainspring Segment with Carbon Nanotube Coating --- p.10 / Chapter 2.1 --- Introduction --- p.10 / Chapter 2.2 --- Coating on the mainspring --- p.12 / Chapter 2.2.1 --- Experimental Setup for Finding the Young's Modulus --- p.12 / Chapter 2.2.2 --- Elastic Modulus of the mainspring without coating --- p.15 / Chapter 2.2.3 --- Elastic Modulus of the mainspring with coating --- p.18 / Chapter 2.2.4 --- Thickness of the coating --- p.19 / Chapter 2.3 --- Elastic deformation of mainspring --- p.22 / Chapter 2.3.1 --- Mathematical Model Derivation --- p.24 / Chapter 2.3.2 --- Data Analysis --- p.35 / Chapter 2.4 --- Summary --- p.38 / Chapter 3. --- FEA of the Spiral Spring Structure --- p.53 / Chapter 3.1 --- Introduction --- p.53 / Chapter 3.2 --- Model Formation --- p.55 / Chapter 3.2.1 --- Preprocess --- p.56 / Chapter 3.2.2 --- Solver --- p.60 / Chapter 3.2.3 --- Post-process --- p.71 / Chapter 3.3 --- A Comparison between Simulation and Experiment Results --- p.74 / Chapter 3.3.1 --- Experimental setup --- p.74 / Chapter 3.3.2 --- Results Analysis --- p.77 / Chapter 3.4 --- Summary --- p.78 / Chapter 4. --- Conclusions and Future Work --- p.81 / Chapter 4.1 --- Summary of micro spiral spring --- p.81 / Chapter 4.2 --- Contributions --- p.83 / Chapter 4.3 --- Future work --- p.84 / Bibliography --- p.86 / Appendix --- p.91 / Chapter A1 --- "Specification of CSM Instrument, Swiss, Variocouple" --- p.91 / Chapter A2 --- Matlab® program of the spiral spring segment FEA --- p.91 / Chapter A3 --- "The paper: ""Nano-Bearing: A New Type of Air Bearing with Flexure Structure""" --- p.99

This thesis documents a PhD level research program, undertaken at the Industrial Institute Swinburne, Swinburne University of Technology between the years of 1997 and 2000. The research program investigated electromagnetic energy regenerative vibration damping; the process of recovering energy from damped, vibrating systems. More specifically, the main research objective was to determine the performance of regenerative damping for the application of vehicle suspension systems. This question emerged due to the need for continuous improvement of vehicle efficiency and the potential benefits possible from the development of regenerative vehicle suspension. It was noted, at the outset of this research, that previous authors had undertaken research on particular aspects of regenerative damping systems. However in this research, the objective was to undertake a broader investigation which would serve to provide a deeper understanding of the key factors. The evaluation of regenerative vibration damping performance was achieved by developing a structured research methodology that began with analysing the overall requirements of regenerative damping and, based on these requirements, investigated several important design aspects of the system. The specific design aspects included an investigation of electromagnetic machines for use as regenerative damping devices. This analysis concentrated on determining the most promising electromagnetic device construction based on its damping and regeneration properties. The investigation then proceeded to develop an 'impedance-matching' regenerative interface, in order to control the energy flows in the system. This form of device had not been previously developed for electromagnetic vibration damping, and provided a significant advantage in maximising energy regeneration while maintaining damping control. The results from this analysis, when combined with the issues of integrating such a system in vehicle suspension, were then used to estimate the overall performance of regenerative damping for vehicle suspension systems. The methodology and findings in this research program provided a number of contributing elements to the field, and provided an insight into the development of regenerative vehicle systems. The findings revealed that electromagnetic regenerative vibration damping may be feasible for applications such as electric vehicles in which energy efficiency is a primary concern, and may have other applications in similar vibrating systems.

Thesis (M.S.)--Worcester Polytechnic Institute. / Keywords: MEMS; suspension; gyroscope; folded springs; statics. Includes bibliographical references (p. 182-187).

Barton Springs Pool (BSP) is an important ecological and recreational resource to the City of Austin (CoA). Due to sediment accumulation, excessive algal growth, and concern for water velocities through salamander habitat, improving the flow regime of BSP was identified as an important focus for future infrastructure development in Barton Springs Pool. The CoA commissioned this project to develop and test a hydrodynamic model to provide a basis for understanding the flow dynamics of BSP, and to aid in future infrastructure developments in BSP. This phase of the project included the collection of bathymetric and velocity data, creating a hydrodynamic model of BSP that dynamically represents space-time varying 3D velocities, and testing the model using the default settings and an adjustment of the outlet coefficients. The model was run with three targeted inflow scenarios to determine both how the model responds with varying inflows, and to provide a general idea of how flow in BSP is affected by the magnitude of the inflow. The model used was the Fine Resolution Environmental Hydrodynamic Model that solves the 3D non-hydrostatic Navier-Stokes equations in a split hydrostatic/non-hydrostatic approach. The model was run using the default settings and the outputs were compared to available data. Results from these initial runs showed that further calibration is necessary. Model runs under the targeted inflow scenarios showed that as inflow increases, velocities in the upstream portion of BSP increase correspondingly, but this is not reflected in the downstream portion of BSP. / text

The stable isotope compositions (chlorine, oxygen, and hydrogen), major anion concentrations, and major/minor cation concentrations of 37 thermal (any spring water with temperature at least 6.5° C above mean ambient air temperature) and mineral springs from the Cascade volcanic arc system were measured in order to better determine chlorine sources within the Cascades hydrothermal systems, and thus place better constraints on halogen flux through the subduction zone. Typically, most subduction zone flux calculations have been limited to the study of the erupted magmas and gases from fumarole vents, yet magmatic discharge through thermal springs may be considerable, particularly those in the often ignored forearc. Additionally, 9 geochemically well characterized lavas from across the Mt. St. Helens/Mt. Adams region of the Cascade arc (Leeman et al. 2001, 2005) were analyzed for their halogen concentrations, as well as their Cl stable isotope composition. Cl concentrations in the thermal springs range from 6 to 13,850 ppm and have δ37Cl values that range from -0.1‰ to + 1.9‰ (average = +0.8 ± 0.4‰; error = ± 0.2‰), with no systematic variation along or across the arc. The slightly positive values (~0.0 to +0.9‰) may be explained by fluid-rock interaction with underlying lithologic units, such as 37Cl-enriched volcanic sequences, and/or serpentinites or oceanic crust of accreted oceanic terranes. Another process possibly contributing to these positive δ37Cl values, particularly those with δ37Cl > 1‰, is magmatic HCl fractionation during degassing generating an enriched 37Cl vapor which mixes with thermal waters. We cannot completely rule out slab-derived altered oceanic crustal chlorine that has degassed into the springs, although most slab Cl is believed to have already been devolatilized from the slab before reaching sub-arc depths corresponding to longitudes where these springs are located at the surface. Lavas from the Columbia transect across the arc exhibit highest Cl concentrations at the volcanic front compared to the forearc and backarc. Br, like Cl, exhibits highest concentrations along the volcanic front. F and I show a progressive decrease in concentration from forearc to backarc which may demonstrate the putative early surge of fluids/fluid mobile element loss early in subduction at relatively shallow depth. δ37Cl values range from -0.1 to +0.8‰ (error = ± 0.2‰) and may reflect a component of assimilation of crustal material, or is derived from an enriched mantle, although we cannot completely rule out some isotopic fractionation and/or slab-derived chlorine. / text