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<p> This dissertation is a compilation of research results of extensive Fast Scanning Calorimetry studies of two non-crystalline materials: Toluene and Water. </p><p> Motivation for fundamental studies of non-crystalline phases, a brief overview of glassy materials and concepts and definitions related to them is provided in Chapter 1. Chapter 2 provides fundamentals and details of experimental apparata, experimental protocol and calibration procedure. </p><p> Chapter 3 &amp; 4 provides extensive studies of stable non-crystalline toluene films of micrometer and nanometer thicknesses grown by vapor deposition at distinct deposition rates and temperatures and probed by Fast Scanning Calorimetry. Fast scanning calorimetry is shown to be extremely sensitive to the structure of the vapor-deposited phase and was used to characterize simultaneously its kinetic stability and its thermodynamic properties. According to our analysis, transformation of vapor -deposited samples of toluene during heating with rates in excess 100,000 K/s follows the zero-order kinetics. The transformation rate correlates strongly with the initial enthalpy of the sample, which increases with the deposition rate according to sub-linear law. Analysis of the transformation kinetics of vapor deposited toluene films of various thicknesses reveal a sudden increase in the transformation rate for films thinner than 250 nm. The change in kinetics correlates with the surface roughness scale of the substrate, which is interpreted as evidence for kinetic anisotropy of the samples. We also show that out-of-equilibrium relaxation kinetics and possibly the enthalpy of vapor-deposited (VD) films of toluene are distinct from those of ordinary supercooled (OS) phase even when the deposition takes place at temperatures above the glass softening (Tg). The implications of these findings for the formation mechanism and structure of vapor deposited stable glasses are discussed. </p><p> Chapter 5 and 6 provide detailed Fast Scanning Calorimetry studies of amorphous solid water in bulk and confining geometry (ultrathin films and nano-aggregates). Bulk-like water samples were prepared by vapor-deposition on the surface of a tungsten filament near 140 K where vapor-deposition results in low enthalpy glassy water films. The vapor deposition approach was also used to grow nano-aggregates (2- 20 nm thick) and multiple ultrathin (approximately 50 nm thick) water films alternated with benzene and methanoic films of similar dimensions. When heated from cryogenic temperatures, the ultrathin water films underwent a well manifested glass softening transition at temperatures 20 degrees below the onset of crystallization. The thermograms of nano-aggregates of ASW films show two endotherms at 40 and 10 K below the onset temperatures of crystallization. However, no such transition was observed in bulk-like water samples prior to their crystallization. These results indicate that water in confined geometry demonstrates glass softening dynamics which are dramatically distinct from those of the bulk phase. We attribute these differences to water's interfacial glass transition which occurs at temperatures tens of degrees lower than that in the bulk. Implications of these finding for past studies of glass softening dynamics in various glassy water samples are discussed in chapter 5 and 6.</p>

Environmental degradation from problems of the 'Brown Agenda' is an everyday reality in Kenya's rapidly growing urban centres; and it is the low-income majority who are most affected. Deficient water supply and sanitation, inadequate solid waste disposal, and poor drainage are among the foremost problems that characterize informal settlements in which indigent urbanites are compelled to live. Analysis of environmental problems at settlement and household level can provide vital information about the appraisive environmental perceptions and cognitions of inhabitants of informal settlements, as well as their satisfaction with the infrastructural services to which they have access and their housing conditions, in general. Such information is essential to the formulation of apposite strategies for sustainable improvement of environmental conditions in informal settlements. Based largely on a comprehensive review of theoretical perspectives on the urban housing question in the South, international policy responses and experiences with settlement upgrading, this thesis seeks a better understanding of the socioeconomic and physio-environmental dynamics of urban low-income informal settlements and the formulation and implementation of upgrading policies. A comparative analysis of two majengos in Kenya-one of which has been upgraded while the other has not-serves to contextualize the study. The central thesis in the present study is that settlement upgrading is the most rational approach to improving the residential circumstances of the urban poor majority in Kenya. Applying a fundamentally liberal approach, the development of pragmatic opportunities is discussed, and pursuable policies and programmes, which are realistic and implementable, for effective environmental planning and management of urban low-income informal settlements in Kenya are proposed.

<p> The NPDGamma Experiment is measuring the parity-violating correlation A_&gamma; between neutron spin and gamma momentum in the radiative capture of a polarized cold neutron beam on a cryogenic liquid parahydrogen target. This measurement is expected to give insight into theories that incorporate the weak interaction into what is primarily a strongly interacting system. This dissertation discusses the operation and characterization of the liquid hydrogen target, including the calibration of the instrumentation that monitors the state of the hydrogen. An important consideration is the fact that for safety reasons the instrumentation in direct contact with the hydrogen is limited, and so a detailed understanding of the target design and of the properties of hydrogen is required in order to interpret the state of the system. For this experiment, it is essential that the hydrogen be kept mostly in the para state in order to prevent the beam from being significantly depolarized before capture. Since the uncatalyzed conversion rate is slow, an ortho-para conversion loop is used to promote conversion from the room temperature orthohydrogen fraction to the fraction associated with the temperatures of the cryogenic vessel. In addition to the calibration and characterization studies, a method is introduced for placing an empirical limit on the deviation of the orthohydrogen fraction inside the vessel from the desired level associated with the temperature of the ortho-para conversion catalyst and vessel. This method, which does not require precise knowledge of the parahydrogen cross section, involves observing the transmission of the beam through the target while the rate of flow of hydrogen through the ortho-para conversion loop is changed. In addition to the studies of the hydrogen target, this dissertation discusses a calibration of some ³He ion chambers that monitor the flux of the neutron beam and that are used to perform beam transmission measurements. This calibration, which involves a study of the noise inherent in the signal due to neutron capture, does not involve comparison to a separate calibrated detector.</p>

This thesis proposes and evaluates the application of a low-frequency disturbance injection, as an active islanding detection method, in a microgrid with multiple electronically-interfaced Distributed Generation (DG) units. Each DG unit is interfaced to the microgrid through a two-level Voltage-Sourced Converter (VSC). The low-frequency disturbance signal for islanding detection is injected through the q-axis control of each VSC unit. The low-frequency signal is at 1 Hz with an amplitude of up to 2.5 % of the rated VA of the VSC unit and augments the reference signal of the q-axis control. The effectiveness of the low-frequency injection for islanding detection is examined under two distinct VSC control scenarios. In the first scenario, each VSC only injects pre-determined real- and reactive-power components in the system and does not participate in frequency/voltage control. In the second scenario, the VSC controls are also equipped with frequency/real-power and voltage/reactive-power droop characteristics and thus share power and participate in frequency and voltage control of the microgrid, specifically in the islanded mode. The investigations reported in this thesis show that the proposed islanding detection method can effectively detect an islanding event under both VSC control strategies, subject to the conditions that UL and/or IEEE anti-islanding standards impose. The studies show that an islanding event can be detected within 536 ms subsequent to the instant of islanding. As part of this thesis, an eigen analysis software tool has been developed that can systematically investigate the impact of low-frequency disturbance injection on the small-signal stability and dynamic performance of the microgrid, prior and subsequent to an islanding event. This thesis concludes that the low-frequency disturbance injection-based method can be successfully applied to a multi-DG system, since (i) islanding detection is achieved within applicable standards requirements by all DG units in the system, and (ii) the low-frequency disturbance injection signal has no noticeable impact on the dynamics nor the small-signal stability of the system if its magnitude is kept below a pre specified limit.

This thesis proposes and evaluates the application of a low-frequency disturbance injection, as an active islanding detection method, in a microgrid with multiple electronically-interfaced Distributed Generation (DG) units. Each DG unit is interfaced to the microgrid through a two-level Voltage-Sourced Converter (VSC). The low-frequency disturbance signal for islanding detection is injected through the q-axis control of each VSC unit. The low-frequency signal is at 1 Hz with an amplitude of up to 2.5 % of the rated VA of the VSC unit and augments the reference signal of the q-axis control. The effectiveness of the low-frequency injection for islanding detection is examined under two distinct VSC control scenarios. In the first scenario, each VSC only injects pre-determined real- and reactive-power components in the system and does not participate in frequency/voltage control. In the second scenario, the VSC controls are also equipped with frequency/real-power and voltage/reactive-power droop characteristics and thus share power and participate in frequency and voltage control of the microgrid, specifically in the islanded mode. The investigations reported in this thesis show that the proposed islanding detection method can effectively detect an islanding event under both VSC control strategies, subject to the conditions that UL and/or IEEE anti-islanding standards impose. The studies show that an islanding event can be detected within 536 ms subsequent to the instant of islanding. As part of this thesis, an eigen analysis software tool has been developed that can systematically investigate the impact of low-frequency disturbance injection on the small-signal stability and dynamic performance of the microgrid, prior and subsequent to an islanding event. This thesis concludes that the low-frequency disturbance injection-based method can be successfully applied to a multi-DG system, since (i) islanding detection is achieved within applicable standards requirements by all DG units in the system, and (ii) the low-frequency disturbance injection signal has no noticeable impact on the dynamics nor the small-signal stability of the system if its magnitude is kept below a pre specified limit.

Abnormal pressures have been measured in the deep boreholes at the Bruce site, southern Ontario, where a deep geologic repository for low and intermediate level radioactive waste disposal has been proposed. The pressure regime in the stratigraphic units exhibits either higher than hydrostatic pressure (over-pressured) or lower than hydrostatic pressure (under-pressured) are considered to be abnormal. At the Bruce site, the Ordovician sediments are under-pressured while the underlying Cambrian sandstone and the overlying Guelph carbonate are over-pressured. Hypotheses have been documented in literature to explain the phenomenon of abnormal pressures. These hypotheses include osmosis, glacial loading and deglaciation unloading, exhumation of overlying sediments, crustal flexure and the presence of an immiscible gas phase. Previous work on the Bruce site has shown that the under-pressures in the Ordovician limestone and shales could not be explained by glaciation and deglaciation or by saturated analyses. The presence of a gas phase in the Ordovician formations has been determined to be a reasonable cause of the under-pressure developed in the Ordovician shales and limestones at the Bruce site. Support for the presence of a gas phase includes solution concentrations of methane, concentrations of environmental isotopes related to methane and estimates of water and gas saturations from laboratory core analyses. The primary contribution of this thesis is the sensitivity analyses performed on the hydrogeologic parameters with respect to a one dimensional two-phase flow model. First, a one dimensional two-phase air and water flow model was adopted and reconstructed to simulate the long-term evolution of the groundwater regimes at the DGR site. Then the hydrogeologic parameters which impact the presence of under-pressure in the groundwater are investigated. Data required to quantify the properties of geologic media and groundwater are adopted directly from borehole testing and laboratory testing results. The permeable boundaries of the domain are assumed to be water saturated and pressure specified (using hydrostatic conditions in the Guelph Formation and hydrostatic with 120 m over-pressure condition in the Cambrian and Precambrian). Isothermal conditions were assumed, thus constant water density and viscosity values are estimated for the average total dissolved solids (TDS) concentration of the modelled stratigraphic column. A constant diffusion coefficient (a diffusivity of $0.25\times10^{-8}$ m$^2$/s) of air in water is assumed with a saturation-dependent tortuosity. The air generation rate is assumed to simulate the gas phase generated in the Ordovician formations. The numerical simulation of up to 4 million years provides a means to explore the behaviour of gas phase dissipation due to partitioning into the water phase and diffusive transport in the solute phase. Results confirmed that the presence of a gas phase would result in the under-pressure in water.