No description available.

This thesis examines processes causing faulting in the North American crust in the northern Cascadia subduction zone. A combination of seismological methods, including source mechanism determination, stress inversion and earthquake relocations are used to determine where earthquakes occur and what forces influence faulting. We also determine if forces that control faulting can be monitored using seismic anisotropy. Investigating the processes that contribute to faulting in the crust is important because these earthquakes pose significant hazard to the large population centres in British Columbia and Washington State. To determine where crustal earthquakes occur we apply double-difference earthquake relocation techniques to events in the Fraser River Valley, British Columbia, and the San Juan Islands, Washington. This technique is used to identify "hidden" active structures using both catalogue and waveform cross-correlation data. Results have significantly reduced uncertainty over routine catalogue locations and show lineations in areas of clustered seismicity. In the Fraser River Valley these lineations or streaks appear to be hidden structures that do not disrupt near-surface sediments; however, in the San Juan Islands the identified lineation can be related to recently mapped surface expressions of faults. To determine forces that influence faulting we investigate the orientation and sources of stress using Bayesian inversion results from focal mechanism data. More than 600 focal mechanisms from crustal earthquakes are calculated to identify the dominant style of faulting and inverted to estimate the principal stress orientations and the stress ratio. Results indicate the maximum horizontal compressive stress (SHmax) orientation changes with distance from the subduction interface, from margin-normal along the coast to margin-parallel further inland. We relate the margin-normal stress direction to subduction-related strain rates due to the locked interface between the North America and Juan de Fuca plates just west of Vancouver Island. Further from the margin the plates are coupled less strongly and the margin-parallel SHmax relates to the northward push of the Oregon Block. Active faults around the region are generally thrust faults that strike east-west and might accommodate the margin- parallel compression. Finally, we consider whether crustal anisotropy can be used as a stress monitoring tool in this region. We identify sources and variations of crustal anisotropy using shear-wave splitting analysis on local crustal earthquakes. Results show spatial variations in fast directions, with margin-parallel fast directions at most stations and margin-perpendicular fast directions at stations in the northeast of the region. To use seismic anisotropy as a stress indicator requires identifying which stations are primarily in uenced by stress. We determine the source of anisotropy at each station by comparing fast directions from shear-wave splitting results to the SHmax orientation. Most stations show agreement between these directions suggesting that anisotropy is stress-related. These stations are further analysed for temporal variations and show variation that could be associated with earthquakes (ML 3{5) and episodic tremor and slip events. The combination of earthquake relocations, source mechanisms, stress and anisotropy is unique and provides a better understanding of faulting and stress in the crust of northern Cascadia. / Graduate

New approaches to the analysis of trace metal concentrations in seawater have the potential to advance the field of oceanography and provide a more comprehensive understanding of the marine biogeochemical cycles of trace metals and the processes regulating these cycles. Traditional oceanographic methods of trace metal analysis were developed several decades ago using benchtop liquid-liquid extraction (Danielson et al., 1978; Kinrade and Van Loon, 1974; Miller and Bruland, 1994; Moffett and Zika, 1987). More modern techniques utilize flow based solid phase extraction to eliminate the high ionic strength matrix to determine dissolved concentrations with great accuracy and precision but do not allow for the determination of metal speciation in solution (Wells and Bruland, 1998). The method developed here measures oceanographically relevant concentrations of copper (Cu) in seawater via chemiluminescence (Marshall et al., 2003 and Coale et al., 1992) and micro-molar levels of silver (Ag) colorimetrically after automated liquid-liquid extraction. The Zone Fluidics (Marshall et al., 2003) analyzer for trace Cu determined SAFe D2 standard seawater (www.geotraces.org) to be 1.77 nM Cu comparable to the expected consensus value. The method was used to determine dissolved Cu depth profiles for major stations along the Line P Time-series transect (48N 125W - 50N 145W) in the Pacific Ocean during February 2011. This method consumes less than 200 µL of sample and reagents and is performed in less than 3 minutes making it suitable for ship or lab based analysis. / Graduate / 0485 / 0425 / cschwang11@gmail.com

Work zones are an essential part of roads maintenance. Despite all the efforts addressed to reduce work zone’s negative impacts on the road traffic performance and improve the road safety, there still exist work zone related congestions and traffic problems. This thesis aims to study and analyze highway reconstruction/maintenance activities, their impacts and existing ways of reducing these negative effects and investigating the role of Intelligent Transport Systems in improvement of the difficulties caused by work zones. The research of the factors influencing capacity resulted in three factors presented in each considered study. The factors are heavy vehicle percentage, weather conditions and police presence. An unusual approach presented by Weng & Meng (2011) distinguishes among the examined analytical models. Their Decision-Tree model, based on training a large data set, showed significantly lower values of errors of prediction of level-of-service. Three different dynamic late merge systems (DLMS) have been simulated and analyzed using the AIMSUN micro-simulation software. The simulation outcome shows promising results favoring the use of DLMS. Among the simulated systems is extra focus put on the ALINEA algorithm that shows potential to improve traffic flow in work zones. Conducted sensitivity analysis shows different behaving of the ALINEA algorithm due to change of regulator parameter and critical occupancy. In order to investigate performance of the ALINEA algorithm, an extensive research has to be conducted. The research should include various work zone configurations as well as different values of heavy vehicle percentage and the parameters within the algorithms code should be subjects to optimization.

No description available.

A larger amount of funding and attention are going toward highway infrastructure of Ontario for rehabilitation, maintenance and construction projects. These rehabilitation and maintenance activities on highways involve lane closures, which reduce the traffic throughput and cause delays for the road users. The impact of these activities is very important and has led to research into improvements of work zones in Ontario. To prevent the significant cost that these construction delays have on the general public, contractors are required to keep highway lanes open during the peak traffic hours and work at night. However, working at night may reduce the quality of the work by increasing cold joints and construction joints in the pavement, and may increase the amount of time needed to complete the work. Therefore, finding a balance between the times that the lanes can be closed and the times they should be kept open requires an accurate prediction of the construction work zone throughputs, which can increase the efficiency of the contractor work, save money and reduce the user delay costs. Consequently, this study which has been funded by the Ministry of Transportation of Ontario (MTO) Highway Infrastructure Innovation Funding Program (HIIFP) involves measurement of highway construction work zones throughput of Southern Ontario, to determine the factors affecting the throughput. It has been carried out in partnership with researchers at the University of Toronto. For this study, a manual counting method for collecting throughput data has been employed. This involved data collection of variables such as heavy vehicles which had not been included in previous studies. This provides the visual confirmation of queuing and assists in evaluating the intensity of work activity at the work zones. New generic models for throughput have been developed in this research to better describe current state-of-the practice on Southern Ontario highways. Furthermore, a better functioning highway specific model was developed to calculate the throughput of the MTO Southern Ontario Highway network. In addition to development of these new models, this project involved further development and refinement to a spreadsheet based model SZUDA (Simplified work Zone User Delay Analysis) that uses normal hourly traffic flows to calculate the resulting queue for that entire hour and approximate user delay cost associated with road user delay. Overall, the thesis describes a methodology for collection of data in work zones. This involved collection of data during 2009 and 2010 Ontario construction season. Furthermore, the data were then used to develop more reliable generic and highway specific models for the MTO. These models can be used to determine when and how work zones should be established. Finally the refined SZUDA model and case studies demonstrate the impact of various work zone configurations on the traveling public.

Thesis (M.S.)--University of Hawaii at Manoa, 2006. / Includes bibliographical references (leaves 253-259). / xxxvi, 259 leaves, bound ill. (some col.) 29 cm

Lower back injuries are an illness which plague our society. Although almost everyone will experience some form of lower back pain in his or her lifetime, it is a sickness that is poorly understood, calling for new and innovative research. Much of this back pain is attributed to mechanical factors. Hence, it is important to understand the mechanics of the spine and the mechanical effects of degenerative changes that may lead to back pain. The spine is a complex three-dimensional structure and it is therefore necessary to study its mechanics with in vitro tests that replicate physiological movements as closely as possible. Traditional spinal testing machines have been unable to simulate the kinematic behaviour of intervertebral joints as they have limited degrees of freedom and cannot produce dynamic motion. The first aim of this research was to commission a robotic testing facility to overcome the limitations of traditional testing machines. This facility incorporated a six degree-of-freedom (DOF) robot arm with a six DOF force transducer. Mechanical tests performed on this facility could simulate the dynamic three-dimensional kinematics of the lumbar spine. In addition, this research aimed to assess the existence of a region of laxity during spinal joint motion defined as the Neutral Zone, and to determine the effect of specific lesions introduced into the intervertebral disc. To investigate these aims, in vitro mechanical tests on spinal specimens were performed using the robotic testing facility. To ensure these tests produced experimental results that were indicative of the mechanics of the spine in life, the intervertebral disc height had to be representative of the disc height in life. A set of experiments was performed to determine a method for ensuring this. The post-mortem disc height change due to a period of time exposed to a moist environment, freezing, defrosting and application of a constant compressive load was documented in a group of sheep spines. Specimens that were frozen immediately upon removal from the body produced the most predictable results. These specimens required no preloading to ensure the disc height during mechanical testing was similar to that in life. In accordance with this result, specimens used in the ensuing mechanical tests were frozen immediately on removal from the body and stored frozen until required for testing. Tests performed on sheep spines with the robotic facility verified the existence of a Neutral Zone. A criterion was determined that defined the Neutral Zone as the region of spinal joint rotation where the gradient of the load/deformation curve is within +/-0.5 dNm/degree from zero. This definition was used to determine the extent of the Neutral Zone in spinal motion during different movements. A Neutral Zone of approximately four degrees was found in intact spinal motion segments during flexion/extension. Only spinal musculature can stabilise the spine in this region of rotation. The removal of the zygapophysial joints increased the Neutral Zone in flexion/extension by approximately two degrees and caused the appearance of a Neutral Zone in axial rotation of approximately one degree. This suggests that during these motions, the zygapophysial joints are the main passive stabilisers. The mechanical effects of intervertebral disc lesions were examined by experimentally introducing three types of tears (rim lesions, radial tears and concentric tears) into sheep intervertebral discs and comparing the mechanical response of the injured joint to the joint's response prior to the creation of the lesions. Radial tears and concentric tears had no effect on the maximum moments resisted by the intervertebral disc or the hysteresis of the joint's response to motion. An anterior rim lesion increased the Neutral Zone by approximately 1.5 degrees and reduced the maximum moment resisted by the intervertebral disc by approximately 20% during extension in L1/L2 specimens. Rim lesions were also found to reduce the maximum moment resisted by the intervertebral disc in lateral bending and axial rotation for all levels by approximately 15% and 25% respectively. Rim lesions did not affect the hysteresis of intervertebral disc motion. In summary, this research commissioned a robotic testing facility capable of simulating the dynamic, three-dimensional kinematics of the lumbar spine and provided a unique insight into the three-dimensional mechanics of intervertebral joints. Testing was performed on sheep joints, however the outcomes provide an insight into the mechanical response of the human spine. The Neutral Zone was shown to exist but only in flexion/extension. This implies that damage to the spinal muscles may produce an unstable structure during flexion/extension within this Neutral Zone. Rim lesions reduce the ability of the intervertebral disc to resist all modes of motion. This suggests that the presence of rim lesions will produce overloading of other spinal elements and instigate progressive degenerative changes.

For Maori, the management fo New Zealand�s coast and its resources is fundamental to their cultural identity. Iwi and hapu throughout New Zealand have close relationships with the coast and unique rights and responsibilities for its future management. However, there does not appear to be wide recognition of the crucial role of Maori in New Zealand�s coastal management regime. Co-management initiatives in coastal management, particularly under the Conservation Act 1987, Resource Management Act 1991 and several legislative initiatives controlling fisheries management, are explored and critiqued. Overall, the initiatives demonstrate that progress is being made in coastal management for better protection of Maori coastal values. Nevertheless, there is scope for further improvements concerning greater Maori involvement in coastal management. Recommendations for genuine co-management systems in New Zealand�s coastal management regime include effective communication between iwi and Government; appreciation of the unique nature of each iwi in New Zealand; involvement of a third party communicating between iwi and Government representatives; appropriate funding and resources to maintain the co-management system, and encouragement and motivation from the Government to initiate and maintain the co-management system.

Thesis (Ph.D. - Hydrology and Water Resources)--University of Arizona. / Includes bibliographical references (leaves 52-62).