Approximately one out of every seven Canadians over the age of 15 years (3.4 million people) has some level of disability. The increasing prevalence of disability in our aging society is commonly accepted as fact with both disability and the severity of disability gradually increasing with age (Statistics Canada, 2001). Recognizing that persons with disabilities often face "barriers" to full participation in society, some provinces have enacted human rights or accessibility planning legislation to remove these barriers. This study examines the process of accessibility planning for persons with disabilities within Canadian municipalities with a population of between 50,000 –500,000, otherwise referred to as mid-size cities (MSC). The underlying assumption of this research is that mid-size Canadian municipalities are carrying out some form of accessibility planning using planning instruments [or other tools] to remove barriers and improve accessibility for persons with disabilities. The purpose of this study is to determine: first, what planning instruments are being used in the design of open space and built environments in MSCs to remove physical barriers, and what other tools are available to attain greater accessibility for persons with disabilities living in mid-size urban settings. Secondly, to consider who is involved in the implementation and use of planning instruments and other tools, and to determine what are their respective roles. Third, to discover the conditions under which planning instruments and other tools are being applied, to learn what financial or other resources are being allocated and how are they being allocated in the short and long term. This study concludes that planning instruments are being used to improve accessibility for persons with disabilities in mid-size Canadian municipalities. Planning tools are not the only way to remove barriers to persons with disabilities. Furthermore, the effectiveness of those tools is clearly contingent upon available human and financial resources. Nevertheless, the study finds that municipal planners and others are using these essential planning tools in a variety of ways to remove physical barriers to accessibility. Inherent in all efforts to remove barriers is the active involvement of persons with disabilities. Thus, involving persons with disabilities in the development and application of planning instruments and other tools has the potential to build the foundation of successful accessibility planning efforts in Canadian mid-size communities. These conclusions have implications for research in the area of accessibility planning and recommendations for Canadian planning practice.

The purpose of this research is to understand if and how downtown university campuses contribute to mid-size city downtown revitalization, how this contribution is measured, and the implications for planning practice and planning theory. To address this research question, a mixed methods approach was used which included a literature review, the use of two case studies, a survey administered to downtown businesses, a web-based survey administered to students, faculty and staff and interviews conducted with municipal planners. The two case studies were: Wilfrid Laurier University’s Faculty of Social Work (WLU FSW) in downtown Kitchener, Ontario and the University of Waterloo’s School of Architecture (UW SA) in downtown Cambridge, Ontario. The findings of this research indicate that downtown university campuses do contribute to downtown revitalization in mid-size cities. The WLU FSW and UW SA campuses are not, however, a panacea for their respective downtowns, nor are they significant contributors to downtown retailing or a major catalyst. Rather, the WLU FSW and UW SA campuses act as stabilizing influences on the downtown, bringing confidence to and about the downtown for residents, potential downtown visitors and potential downtown investors. They are examples of revitalization strategies that contribute to the improved reputation of the downtown and city. They are strategies that build on existing downtown strengths (e.g. adaptive re-use of heritage buildings, the complementing of existing businesses and services) and they are part of a larger community vision for these downtowns. The WLU Faculty of Social Work campus and the UW School of Architecture campus are both examples of effective and successful university-community partnerships. Recommendations based on the findings of this research are provided for municipalities, planning practitioners and academics. This research contributes to the limited but expanding literature on mid-size cities, mid-size city downtown revitalization and university-community partnerships. Recommendations for further research are also provided.

The Far-Offset Active-Source Imaging of Mantle (FAIM) experiment was conducted along an 800-km-long transect in the Western Atlantic to study the evolution of 108-157 m.y. lithosphere. The main transect (Line 1) crosses a transition from slow (13-14 mm/yr in half rate) to ultra-slow (~8 mm/yr) paleo spreading rates, and thus represents an ideal setting to study spreading-rate dependent processes as expressed in preserved lithospheric structure. This thesis presents results of four analysis efforts along this transect. We present a crustal model based on seismic refraction and wide-angle traveltime modeling, we extend the crustal model to an upper lithosphere density model using gravity constraints, we constrain Poissons ratio in oceanic Layer 3 using converted shear-wave phases, and we consider regional lithospheric structure by analysis of geoid/topography ratios. The crustal model indicates that a transition in crustal thickness accompanies the spreading-rate change, with the crust produced at slow rates being 1.0-1.5 km thinner. The gravity modeling shows that a density model can be constructed that simultaneously satisfies observed gravity, seismic constraints on crustal thickness, and our expectation of isostacy if ~1.3 km of low-density material is distributed into the upper 30-60 km of the mantle. This amount of material (~1.3 km) roughly equals the difference in thickness between slow and ultra-slow spreading crust, suggesting that that the thinner crust formed during very slow spreading arises due to melt retention in the mantle rather than decreased mantle melting. Modeling of mode-converted S-wave phases reveals a uniform of Poissons ratio (~0.27) in the lower crust. Along with the observation of sharp crust/mantle boundary, this result suggests that crust along the FAIM transect is primarily melt-derived igneous crust. Geoid versus topography relationships along Line 1 and nearby parallel tracks show abrupt changes that may originate from lateral changes in mantle density, possibly in response to the transition from slow to ultra-slow spreading. This type of observation may enable us to extend our inferences to a more regional scale.

This thesis describes the research, design, and development of a mid-drive wheelchair for use by the elders living independently, in assisted living facilities, and in nursing homes created by a design team at Georgia Tech's Center for Assistive Technology and Environmental Access (CATEA). This wheelchair stands to significantly improve the mobility of elders through better drive wheel placement and design features that could stand to improve their quality of life.

Mid-level administrators comprise the largest group of administrative professionals on college campuses today. These professionals affect the daily lives of students and contribute significantly to the overall coordination of institutional resources and activities. Despite the importance of their role in administering programs, services, and other functions central to the mission of the university, little research has been conducted examining the issues that impact their motivation and job performance. The purpose of this qualitative case study was to increase understanding of the factors affecting work motivation of mid-level student affairs administrators through the identification of motivational determinants and an exploration of whether these determinants differed based on the career stage of the mid-level administrator. This study used Vroom’s theory of work motivation, specifically valence, instrumentality, and expectancy, to determine the factors motivating mid-level student affairs administrators to perform in their work roles. Ten mid-level student affairs administrators at a large, public, Hispanic-serving institution were interviewed. Findings suggest that mid-level student affairs administrators are motivated by the opportunity to serve students and influence the development of their subordinate staff. Participants cited internal drives, such as work ethic and a need for achievement, and external factors, such as opportunities to engage in their own professional development, recognition, and pay, as motivators. Some participants maintained that the culture of the institution had an impact on their motivation to perform. Individually and collectively, these motivational determinants influenced the effort and performance of these mid-level administrators in their work roles. Overall, the participants reported that they enjoyed their work and felt rewarded for their efforts in their work roles. Findings suggest that important differences in motivational determinants as a function of career stage are negligible. Implications and recommendations to implement initiatives to promote and support the identified motivational factors are discussed.

Hydrothermal systems at oceanic spreading centers play an important role in the composition of seawater, the formation of ore deposits, the support of microbial and macrofaunal ecosystems, and even for the development of life on early earth. These circulation systems are driven by heat transport from the underlying magma chamber, where latent heat of crystallization and sensible heat from cooling are transferred by vigorous, high Rayleigh number convection through a thin conductive boundary layer. The traditional study of magmatic-hydrothermal systems is primarily based on the time-series observation, which takes the form of repeat visits, continuous offline monitoring by autonomous instruments, or continuous online monitoring by instruments with satellite or cable links to shore. Although a number of studies have deployed autonomous monitoring instruments at vents and around mid-ocean ridges to investigate geophysical and hydrothermal processes, the data are still rather limited and a comprehensive understanding of magma-hydrothermal processes at oceanic spreading centers is lacking. Numerical modeling needs to be employed to elucidate the dynamic behavior of magmatic hydrothermal systems and for testing completing hypotheses in these complex, data-poor environments. In this dissertation, I develop a mathematical framework for investigating heat transport from a vigorously convecting, crystallizing, cooling, and replenished magma chamber to an overlying hydrothermal system at an oceanic spreading center. The resulting equations are solved numerically using MATLAB. The simulations proceed step-by-step to investigate several different aspects of the system. First, I consider a hydrothermal system driven by convection, cooling and crystallization in a ~ 100 m thick basaltic magma sill representing an axial magma chamber (AMC) at an oceanic spreading center. I investigate two different crystallization scenarios, crystal-suspended and crystal-settling, and consider both un-replenished and replenished AMCs. In cases without magma replenishment, the simulation results for crystals-suspended models show that heat output and the hydrothermal temperature decrease rapidly and crystallinity reaches 60% in less than ten years. In crystals-settling models, magma convection may last for decades, but decreasing heat output and hydrothermal temperatures still occur on decadal timescales. When magma replenishment is included, the magmatic heat flux approaches steady state on decadal timescales, while the magma body grows to double its original size. The rate of magma replenishment needed ranges between 5 x 10⁵ and 5 x 10⁶ m³/yr, which is somewhat faster than required for seafloor spreading, but less than fluxes to some terrestrial and subseafloor volcanoes on similar timescales. The heat output from a convecting, crystallizing, replenished magma body that is needed to drive observed high-temperature hydrothermal systems is consistent, with gabbro glacier models of crustal production at mid-ocean ridges. Secondly, I study the heat transfer model from a parametric perspective and examine the effects of both initial magma chamber thickness and magma replenishment rate on the hydrothermal heat output. The initial rate of convective heat transfer is independent of the initial sill thickness; but without magma replenishment, the rate of decay of the heat output varies linearly with thickness, resulting in short convective lifetimes and decaying hydrothermal temperatures for sills up to ~ 100m thick. When magma replenishment is included in crystals settling scenarios at constant or exponentially decreasing rates of ~ 10⁻⁸ m/s to the base of the sill, growth of the sill results in stabilized heat output and hydrothermal temperature on decadal timescales and a relatively constant to increasing thickness of the liquid layer. Sills initially ~ 10 m thick can grow, in principal, to ~ 10 times their initial size with stable heat output and a final melt thickness less than 100m. Seismic data provides evidence of AMC thickness, but it can not discriminate whether it denotes initial magma thickness or is a result of replenishment. These results suggest that magma replenishment might not be seismically detectable on decadal time scales. Periodic replenishment may also result in quasi-stable heat output, but the magnitude of the heat output may vary considerably in crystals suspended models at low frequencies; compared to crystals settling models. In these models the direct coupling between magmatic and hydrothermal heat output suggests that heat output fluctuations might be recorded in hydrothermal vents; but if damping effects of the basal conductive boundary layer and the upflow zone are taken into account, it seems unlikely that heat output fluctuations on a time scale of years would be recorded in hydrothermal vent temperatures or heat output. Thirdly, I extend the work to the binary system motivated by the fact that the real magmas are multi-component fluids. I focus on the extensively studied binary system, diopside-anorthite (Di-An), and investigate the effects of convection of a two-component magma system on the hydrothermal circulation system through the dynamic modeling of both temperature and heat output. I model the melt temperature and viscosity as a function of Di concentration, and incorporate these relations in the modeling of the heat flux. Simulations comparing the effects of different initial Di concentrations indicate that magmas with higher initial Di concentrations convect more vigorously, which results in faster heat transfer, more rapid removal of Di from the melt and growth of crystals on the floor. With magma replenishment, I assume that the magma chamber grows either horizontally or vertically. In either case magma replenishment at a constant rate of ~ 10⁻⁸ m³/a can maintain relatively stable heat output of 10⁷-10⁹ Watts and reasonable hydrothermal vent temperatures for decades. The final stabilized heat flux increases with increasing Di content of the added magma. Periodic replenishment with a 10 year period results in temperature perturbations within the magma that also increase as a function of increasing Di. With the simple magma model used here, one can not discern conclusively whether the decrease in magma temperature between the 1991/1992 and the 2005/2006 eruptions at EPR 9°50'N involved replenishment with more or less evolved magmas. Fourthly, I investigate a high-silica magma chamber as the hydrothermal circulation driver. I construct viscosity models for andesite and dacite melts as a function of temperature and water content and incorporate these expressions into a numerical model of thermal convective heat transport from a high Rayleigh number, well-mixed, crystallizing and replenished magma sill beneath a hydrothermal circulation system. Simulations comparing the time dependent heat flux from basalt, 0.1wt.% andesite, 3wt.% andesite, and 4wt.% dacite, indicate that higher viscosity magmas convect less vigorously, which results not only in lower heat transport and hydrothermal vent temperatures, but also in a lower decay rate of the vent temperature. Though somewhat colder, hydrothermal systems driven by unreplenished high-silica melts tend to have a longer lifetime than those driven by basalts, assuming a heat output cutoff of 10⁷ Watts. As in the basaltic case, magma replenishment at a rate of ~ 3 x 10⁵ - 3 x 10⁶ m³/a can maintain relatively stable heat output of 10⁷-10⁹ Watts and hydrothermal vent temperatures for decades. Idealized models of porous flow through the lower crust suggest such replenishment rates are not likely to occur, especially for high-viscosity magmas such as andesite and dacite. Long term stability of hydrothermal systems driven by these magmas requires an alternate means of magma replenishment. Finally, the dissertation concludes by discussing some avenues for future work. Most important of these are to: (1) couple magma convection with more realistic hydrothermal models and (2) link magma chamber processes to better physical models of replenishment and eruption.

<p>The objective of this thesis has been to investigate novel host material configurations for high-power end-pumped Er-Yb co-doped, or Yb doped microchip lasers and try to increase their performance. In Er-Yb co-doped systems, the main limitation is the thermal shortcomings of the phosphate glass host material. The thesis presents some novel results that contribute to the search for a crystalline replacement. In Yb doped systems, most end-pumped schemes reported have been using relatively low-power single-emitter diodes. The thesis presents experiments with Yb:KGW microchips end-pumped by high-power diode bars. Another common limitation of end-pumped Yb microchip lasers is the thermal lens that destabilizes the cavity and decreases the beam quality. The approach to reduce the thermal lens by using an athermal propagation direction has been evaluated and the results are presented in the thesis.</p><p>In the search for a crystalline host material for Er-Yb systems, borates have been found increasingly interesting. Consequently, we started out by investigating Gadolinium-calcium-oxoborate, GdCOB, which could be grown in platinum crucibles. It was found that the cw performance of such monolithic microchips is quite comparable to glass hosts in terms of slope efficiency, but the threshold is significantly larger. As for Q-switched performance, which is essential to most Er-Yb applications, the first efficient Q-switched results with a crystalline host is presented in the thesis. Similar to the cw regime, the slope efficiencies are comparable to glass, while the threshold is quite high. However, the perhaps most important parameter, maximum output power before thermal fracture, is neither significantly improved nor worsened compared with phosphate glass. This is believed to be due to higher threshold and a stronger thermal expansion that negates the benefit of a thermal conductivity that is only 2-3 times higher. To find a host material that could withstand higher pump powers, we turned our attention to the double-tungstates KGW and KYW, which have higher thermal conductivity and higher cross-sections. They have, however, energy level lifetimes which differ significantly from glass or borates and as a consequence, a thorough spectroscopic investigation has been undertaken to optimize dopant concentrations. Laser experiments on crystals with dopant concentrations based on this investigation are expected in the near future.</p><p>When pumping Yb:KGW with a high-power diode bar, we achieved output powers of 9 – 12.4 W under different experimental conditions with incident powers of 18.3 – 26 W. The incident power of 26 W in one design was enough to fracture the crystal. Using a crystal cut for propagation along an athermal direction and comparing it with an identical b-cut crystal, we found that the thermal lens in the athermally oriented crystal was about a factor two weaker at the same absorbed power.</p>

Oak savannas are among the most imperiled ecosystems in the United States as a result of habitat degradation and consequently, associated vegetation and wildlife communities have also declined. I evaluated savanna restoration strategies on twelve case studies in Tennessee and Kentucky. These case studies represented a broad range of disturbances and the most advanced savanna restoration sites within the region. I evaluated vegetation and breeding bird responses to landscape and overstory conditions across sites through a meta-analysis. Total grass and forb cover were influenced by overstory metrics but not by topography (P >0.05). Oak regeneration density was influenced by canopy cover, while oak competitor regeneration density was influenced by percent slope and sapling density (P <0.05). With respect to breeding birds, I found forest species persisted within case studies despite substantial disturbance; shrub/scrub birds were common on disturbed sites. Only three obligate grassland bird species, Tyrannus tyrannus, Aimophila aestivalis, Spiza americana, were observed on my sites. Relative abundance of Passerina cyanea was positively related to the groundlayer development; whereas that of Melanerpes erythrocephalus was positively related to basal area of dead trees (P <0.05). Based on my results, canopy reduction and growing-season burns may both be critical for the restoration of savannas within the region. Drum-chopping is a tool that may expedite oak savanna restoration through improved woody competition control, however, its effectiveness has not been investigated. Therefore, I evaluated drum-chopping effects on vegetative structure at Catoosa Wildlife Management Area, Tennessee, during 2008 and 2009 using two adjacent sites with similar fire and overstory removal histories. One site was subjected to drum-chopping in September of 2007, while an adjacent site (control) was not chopped. Drum-chopping reduced grass and forb cover, and oak seedling density, but increased bare ground and density of vines and shrubs versus the control (P <0.05). Except for bare ground, differences were no longer apparent in the second year. Based on my results, drum chopping may reduce midstory vegetation too thick to be effectively controlled by fire, but otherwise has limited utility as a restoration tool. Although wildlife managers have tried to restore savannas using prescribed fire and overstory canopy removal, use of other tools may be warranted. One such method is drum-chopping, which has been used elsewhere to reduce woody competition. However, the effectiveness of this method in restoring oak savannas has not been evaluated. Therefore, I evaluated drum-chopping effects on plant composition at Catoosa Wildlife Management Area on the Cumberland Plateau in Tennessee. Two adjacent sites with similar fire and overstory removal histories were selected for this study. One of these sites was subjected to drum-chopping (CHOP) in September of 2007, the adjacent site was not chopped (NOCHOP). Grass cover differed by treatment (P <0.01) and year*treatment (P = 0.03). Forb cover differed by treatment (P <0.01) and legume cover differed by year (P <0.01), treatment (P <0.01), and year*treatment (P = 0.01). Exposed bare ground differed by year (P <0.01) and treatment (P <0.01). Exposed leaf litter differed by year (P <0.01). Vines and shrubs (<1.37m tall) differed by treatment (P <0.01). Oak seedling (0-30.48 cm tall) densities differed by treatment (P = 0.05). Based on my results, drum chopping may be a valuable tool where woody encroachment has become too thick for fire to be effective or herbicides are not a viable option, but otherwise has limited utility as a tool for oak savanna restoration.

Thesis (S.M.)--Joint Program in Oceanography (Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences and the Woods Hole Oceanographic Institution), 2001. / Includes bibliographical references (leaves 44-48).

Thesis (M.A.)--Lancaster Bible College, 2002. / Includes bibliographical references (leaves 65-66).