Sixteen percent of New Zealand’s power comes from geothermal sources which are primarily located within the Taupo Volcanic Zone (TVZ). The TVZ hosts twenty three geothermal fields, seven of which are currently utilised for power generation. Ngatamariki Geothermal Field is the latest geothermal power generation site in New Zealand, located approximately 15 km north of Taupo. This was the location of interest in this project, with testing performed on a range of materials to ascertain the physical properties and microstructure of reservoir rocks. The effect of burial diagenesis on the physical properties was also investigated. Samples of reservoir rocks were taken from the Tahorakuri Formation and Ngatamariki Intrusive Complex from a range of wells and depths (1354-3284 mbgl). The samples were divided into four broad lithologies: volcaniclastic lithic tuff, primary tuff, welded ignimbrite and tonalite. From the supplied samples twenty one small cylinders (~40-50mm x 20-25mm) were prepared and subjected to the following analyses: dual weight porosity, triple weight porosity, dry density, ultrasonic velocity (saturated and dry) and permeability (over a range of confining pressures). Thin sections impregnated with an epoxy fluorescent dye were created from offcuts of each cylinder and were analysed using polarised light microscopy and quantitative fluorescent light microstructural microscopy. The variety of physical testing allowed characterisation of the physical properties of reservoir rocks within the Ngatamariki Geothermal Field. Special attention was given to the petrological and mineralogical fabrics and their relation to porosity and matrix permeability. It was found that the pore structures (microfractures or vesicles) had a large influence on the physical properties. Microfractured samples were associated with low porosity and permeability, while the vesicular samples were associated with high porosity and permeability. The microfractured samples showed progressively lower permeability with increased confining pressure whereas samples with a vesicular microstructure showed little response to increased confining pressure. An overall trend of decreasing porosity and permeability with increasing density and sonic velocity was observed with depth, however large fluctuations with depth indicate this trend may be uncertain. The large variations correlate with changes in lithology suggest that the lithology is the primary control of the physical properties with burial diagenesis being a subsidiary factor. This project has established a relationship between the microstructure and permeability, with vesicular samples showing high permeability and little response increased confining pressure. The effects of burial diagenesis on the physical properties are subsidiary to the observed variations in lithology. The implications of these results suggest deep drilling in the Tahorakuri Formation may reveal unexploited porosity and permeability at depth.

Oxygen isotopes and major and trace element geochemistry have been used to evaluate the geochemical and tectonic history of a Franciscan hornblende-amphibolite and a eclogite block from Ring Mountain, Tiburon and three eclogite/blueschist blocks from Jenner Beach, California, all blocks have experienced varying amounts of retrogression. Relative to the presumed basaltic protolith, enrichments in large ion lithophile elements (LILEs) indicate interaction with sediment derived fluids in the retrograde eclogite and retrograde blueschist samples and high Mg, Cr, and Ni in actinolite rind indicate interaction with ultramafic rock. The [delta]¹⁸O values of chlorite from the Ring Mountain hornblende-amphibolite and the eclogite block have a narrow range of [delta]¹⁸O values (+7.7-8.2%₀, n=8) and actinolite from actinolite rind on the eclogite block from Ring Mountain and the blueschist/eclogite blocks from Jenner Beach are (+7.8-8.5%₀, n=5). Chlorite-actinolite geothermometry yields temperatures of 200-280°C for actinolite rind formation. Additionally, the [delta]¹⁸O values of both chlorite and actinolite at these temperatures indicates equilibrium with the measured value of Tiburon serpentinites, (7.6 to 8.1%₀, n = 3 Wenner and Taylor, 1974). Oxygen isotope analyses of garnet mineral separates from the eclogite and hornblende-amphibolite from Ring Mountain have [delta]¹⁸O values of +6.8±0.3%₀ (n=7), and +8.2±0.2%₀ (n=7), respectively. Garnets from the three eclogite/blueschist blocks at Jenner Beach have a [delta]¹⁸O value of +9.8±0.7%₀, (n=23). The difference in [delta]¹⁸O values of garnets between the high-grade blocks is likely due to in situ hydrothermal alteration of the seafloor basalt prior to subduction. The geochemical trends can be explained by a model in which during the early stages of subduction pieces of altered oceanic crust are detached from the downgoing slab and incorporated into the mantle wedge soon after reaching peak eclogite or amphibolite facies conditions. As subduction continues, the hanging wall cools and fluids released from subducted sediments infiltrate the overlying mantle wedge. As the blocks cool they develop a retrograde blueschist facies overprint under relatively static conditions. With cooling of the hanging wall and infiltration of sedimentary fluids, serpentinization induces reaction between the blocks and surrounding mantle wedge and Mg-rich actinolite rind is formed. The blocks are then plucked from the mantle wedge and incorporated into the subduction channel where they flow back to the surface via corner flow. / text

The lower Trinity River in Texas flows 180 river kilometers from Livingston Dam to Trinity Bay. Like many sandy coastal rivers the lower Trinity is geomorphically active. Within this 180-km reach, the river exhibits three styles of channel geometry and kinematic behavior that have been characterized using aerial photographs spanning the past 60 years, as well as bathymetric surveys and field work completed over the past 5 years. The three channel zones are connected to spatial change in properties of the sediment transport field. The upstream zone is defined by channel-bed incision, relatively small and coarse-grained bars, and relatively low rates of lateral channel migration. These properties of the upstream zone are connected to the discharge of water with effectively no bed-material load from Livingston Dam. Eventually the channel flow scours enough sediment from the channel bed and sidewalls to reestablish the predicted transport capacity for sand in the river, marking the transition to the central zone. This zone is defined by the largest bars and channel bends with the highest rates of lateral migration that persist downstream until the transport of sand and gravel is influenced by the backwater hydraulics connected with the shoreline at Trinity Bay. This downstream river zone is characterized by very small point bars, the deepest flows at most discharges, and lower rates of channel migration. Studying the connections and transitions between these three river zones leads to a more complete understanding of the coevolution of river geometry and profile, channel kinematics, and downstream change in sediment transport in the coastal zone. / text

Studies show that the use of cleaning products is related to adverse respiratory health effects ranging from irritation to asthma. Yet exposure to these chemicals is poorly understood. This dissertation summarizes the current state of knowledge of inhalation exposure to toxic chemicals in consumer cleaning products. An improved two-zone model that treats personal air space as distinct from bulk room air is presented. The model accounts for air exchange between the two zones, dynamic source characteristics (i.e., the time-varying liquid concentrations and emission rates of pollutants within a mixture), and the characteristics of chemical use (e.g., how frequently a cleaning chemical is applied to a new area). To assess exposure to cleaning products and validate the improved two-zone model twenty-three experiments, encompassing six cleaning scenarios, were completed in an environmentally-controlled chamber with a thermal mannequin. Then, the model was used to predict exposure for four hypothetical cleaning scenarios and compared against other models. The model's applicability is restricted by limited data available for parameterization. At low air exchange rates gas-phase experimental results show concentrations in the breathing-zone of the mannequin exceeded concentrations predicted by the well-mixed model by factors up to 2.1. Breathing-zone concentrations also exceed those measured at centralized room monitors by factors up to 6.1. Thus, studies that use the centralized room monitors or the well-mixed model as a surrogate for breathing-zone concentrations could potentially underpredict exposure at low air exchange rates. The two-zone model provides the best prediction of exposure to cleaning tasks, at low air exchange rates. The next best model is the well-mixed model with an exponentially decreasing emission rate, followed by the well-mixed model with a constant emission rate. At high air exchange rates the well-mixed assumption appears to be valid. The inner-zonal volume and inter-zonal air exchange were independent of fresh air ventilation rate. But both were dependant on the mannequin's body position, with standing having the highest inner-zonal volume and lowest intra-zonal air exchange rate of the three body positions investigates (standing, bent over 45°, and hands and knees). / text

Moisture dynamics in the critical zone have significant implications for a variety of hydrologic processes, from water availability to plants, to infiltration and groundwater recharge rates. These processes are perturbed by events such as wildfires, which may have long-lasting impacts. In September 2011, the most destructive wildfire in Texas history occurred in and around Bastrop State Park, which was significantly affected; thus this is a rare opportunity to study soil moisture under such burned conditions. A 165 m long transect, bridging burned and unburned areas, was established within the “Lost Pines” of the park. Soil moisture was monitored using a variety of methods, including 2D electrical resistivity imaging (using dipole-dipole and Schlumberger configurations), handheld measurements using a ThetaProbe, and readings at depth using PR2 profile probes. Field measurements were collected at approximately one-month intervals to study temporal and seasonal effects on soil moisture. Greater soil moisture was found near the ground surface at the heavily burned end of the transect, where the majority of trees were killed by the fire and grasses now dominate, and lower near-surface soil moisture and higher resistivity at the opposite end of the transect, which is still populated by pine trees. These variations can likely be attributed to the vegetative variations between the two ends of the transect, with trees consuming more water at one end and the ground cover of grasses and mosses consuming less water and helping reduce evaporation at the burned end. Soil texture differences could also be a factor in greater soil moisture retention at the burned end of the transect. Given the higher moisture throughout the soil profile at the burned end of the transect, this could be an indication of greater infiltration, and could increase recharge, at least in the short term. / text

The area surrounding Capital Metro’s Martin Luther King, Jr. (MLK) MetroRail Station was designated a Transit-Oriented Development (TOD) zone and a plan was published in 2009. However, to date there has been very little development, and the development that has occurred is significantly different from what is called for by the plan. This report examines some of the difficulties of implementing TOD in Austin and the factors that could contribute to successful TOD projects. A market analysis of the MLK Station Area explores the economic feasibility of developing land there to its highest and best use. It concludes that the general dearth of TOD in Austin and lack of dense, mixed-use development in the MLK neighborhood make the kind of development called for in the MLK Station Area Plan excessively risky for developers. However, a more conventional multifamily development would be feasible, and increased station-area density could contribute to the success of future TOD. / text

B cell development is a highly organized process, which commences in the fetal liver during embryogenesis and in the bone marrow (BM) after birth. Surface IgM+ immature B cells emigrate from the BM via the blood stream to the spleen and finally differentiate into conventional mature follicular B (FoB) cells and marginal zone (MZ) B cells. Conversely, some sIgM+ immature B cells can also mature into IgD+ FoB cells in the BM. The ubiquitously expressed cell surface glycoprotein CD47 and its receptor signal regulatory protein α (SIRPα) are members of the immunoglobulin superfamily. Both individually and upon their interaction, CD47 and SIRPα have been found to play important role in the homeostasis of T lymphocytes or CD8­ conventional dendritic cells (cDCs) in secondary lymphoid organs. However, their role in regulating B cell homeostasis has remained unknown. The present study describes important roles of CD47 and SIRPα in B cell homeostasis. Lack of SIRPα signaling in adult SIRPα mutant (MT - cytoplasmic domain deletion) mice resulted in an impaired B cell maturation in the BM and spleen, which was also reflected in the blood. In the BM and spleen of SIRPα MT mice, reduced numbers of semi-mature IgD+IgMhi follicular type-II (F-II) and mature IgD+IgMlo follicular type-I (F-I) B cells were observed, while earlier BM B cell progenitors or splenic transitional B cells remained unaltered. In SIRPα MT mice, maturing B cells in BM and spleen were found to express higher levels of the pro-apoptotic protein BIM and contained an increased level of apoptotic cells. In contrast to that for FoB cells, the splenic MZ B cell population was increased with age in SIRPα MT mice without showing an increased level of activation markers. Immunohistochemical analysis revealed an increased follicular localization of MZ B cells in the spleens of SIRPα MT mice. In addition, MZ macrophages and marginal metallophilic macrophages were not restricted to their normal position in SIRPα MT spleens. Interestingly, CD47-deficient (CD47-/-) mice mimicked the FoB cell phenotype observed in SIRPα MT mice and had a reduced number of  FoB cells in the BM, blood and the spleen at 5­6 months of age, but not in younger mice. Similar to SIRPα MT mice, CD47-/- mice also displayed an increased number of splenic MZ B cells. Sera form both mouse strains did not show any signs of an increased production of autoantibodies or antinuclear antigens. BM reconstitution experiments identified a requirement for non-hematopoietic SIRPα signaling for normal B cell maturation in the BM and to maintain normal numbers and retention of MZ B cells in the splenic MZ. On the contrary, hematopoietic SIRPα signaling appeared to be important for FoB cell maturation in the spleen. Interestingly, hematopoietic SIRPα was required for normal MZ retention of MZ macrophages while normal distribution of metallophilic macrophages required non­hematopoietic SIRPα signaling.  Collectively, these findings revealed an important role of CD47 and of SIRPα signaling in B cell homeostasis in different lymphoid organs.

Natural enrichment of ²³⁴U with respect to ²³⁸U was investigated in perched water, vadose zone pore waters, and secondary minerals. The activity ratio (AR) for dissolved ²³⁴U increased from about 1.4 in runoff to >6 in perched water. The AR in the vadose zone increased sharply at a transition that correlated with increased magnetic susceptibility and decreasing hydraulic conductivity. This was evidently caused by auto—oxidative selective leaching controlled by matrix saturation. The direct recoil fractionation mechanism has been proposed for tuffs on the Nevada Test Site, and could imply enhanced retardation of U. Direct recoil was evaluated using a steady state isotopic mass balance formulated to represent matrix pore water, and including first order sorption and selective leaching. Matrix sorption parameters were estimated by selectively leaching intact core with hydroxylamine. Much U was recovered, fractionated similarly to pore water. Interpreting this as isotopic exchange limited by Fickian transport within a sorbent layer, the rate constant and distribution coefficient were estimated. Uranium—series analysis of fracture—lining MnO₂ indicated that isotopic exchange was operant. The isotopic mass balance showed that direct recoil is a minor contribution to fractionation, so the predominant mechanism is selective leaching. This result depends mainly on the sorption rate constant, and where direct recoil is likely such as in roll—front deposits, it implies that the rate constant is smaller than in typical oxidizing waters. Extrapolating matrix properties to formation scale transport, an upper bound on formation scale sorption was inferred from the isotopic mass balance. Formation scale sorption is greater where the perched water table lies in more porous, permeable tuff. The layer diffusion model predicts that the effective sorption rate constant decreases significantly for thicker sorbent layers. Thus although fracture lining MnO₂ minerals are common at Yucca Mountain, U retardation may be strongly rate limited. Elevated AR's (>5) generally signify conditions favorable to U retardation, based on hydraulic isolation from recharge. Elevated vadose zone AR's do not necessarily signify the former presence of perched water, but could be interpreted that way at Yucca Mountain if similar fractionation is not found where past perching is unlikely.

Not available / text

In steel moment resisting frames, the region of the column located within the beam-column joint is known as the panel zone. When a steel moment resisting frame is subjected to lateral load, due to wind or seismic loads, the panel zone is subject to high shear. In some cases, the shear in the panel zone is sufficiently high that the panel zone must be reinforced to increase its stiffness and/or strength. This is normally accomplished by welding doubler plates to the column in the panel zone region. Doubler plates can be a costly feature in steel moment resisting frames because of the substantial amount of welding involved. There has been a large amount of past research that has investigated the required shear strength and stiffness of the panel zone region to establish a basis for sizing doubler plates. However, very little past research has investigated the details of attaching doubler plates to columns. These attachment details can have a significant influence on the structural performance of panel zone and on cost. The overall goal of this research was to conduct preliminary finite element studies that provide insight into several key issues related to the attachment of doubler plates to columns and to identify issues that require further research. The research involved finite element modeling of a simplified representation of beam-to-column joint subjected to monotonic loading. A total of twenty-one analysis cases with different doubler plate attachment details were studied. Issues that were investigated included the effect of welding different edges of the doubler plate to the column (horizontal edges only, vertical edges only, and all four sides), the effect of extending the doubler plate beyond the panel zone region, and the effect of providing two thinner doubler plates of equivalent total thickness on both sides of the column web instead of one thick doubler plate on one side of the column web. In addition, the forces developed in the doubler plate welds were computed from the finite element analysis and compared with current building code requirements for the design of these welds. Observations and preliminary design recommendations on these issues are provided in this thesis, along with recommendations for further research. / text