The purpose of this thesis was to create a computational wrist model that predicts carpal bone motion in order to investigate the complex kinematics of the human wrist. The tuning of this model was primarily based on in vitro, kinematic measurements of the carpal bones obtained from the same cadaver arm as the geometry for the model was generated. A rigid body spring model of the wrist was built using the kinematic simulation software RecurDynTM 6.1. Surface models of the eight carpal bones, the bases of the five metacarpal bones, and the distal parts of the ulna and radius, all obtained from computed tomography (CT) scans of a cadaver upper limb, were utilized as the geometry for this model. Elastic contact conditions between the rigid bodies modeled the influence of the cartilage layers, and ligamentous structures were constructed using nonlinear, tension-only spring elements. Motion of the wrist was simulated by applying forces to the tendons of the five main wrist muscles modeled. Three wrist motions were simulated: extension, ulnar deviation and radial deviation. The model was mainly tuned by comparing the simulated displacement and orientation of the carpal bones with previously obtained CT-scans of the same cadaver arm in deviated (45 deg ulnar and 15 deg radial), and extended (57 deg) wrist positions. Simulation results for the scaphoid, lunate, capitate, hamate and triquetrum are presented here and provide credible prediction of carpal bone movement. The impact of certain model parameters on simulation results has been investigated by performing sensitivity analyses, and their severity has been documented. The results of the first simulations indicate that this model may assist in future wrist kinematics investigations. However, further optimization and validation are required to define and guarantee the reliability of this model. It is suggested that this rigid body spring model may be part of an interacting framework between in vitro and in vivo investigations, as well as other computational models, in order to improve and complement each biomechanical investigation method. / Thesis (Master, Mechanical and Materials Engineering) -- Queen's University, 2007-08-30 16:30:32.543

The spring freshet is the dominant annual hydrologic event occurring on largely nival Arctic river systems. It provides the greatest proportion of freshwater influx to the Arctic Ocean, amongst all other atmospheric input sources. To assess whether any shift in the seasonality of spring freshets has occurred, and how climatic drivers and flow regulation govern trends in sub-basin freshets and their contribution to outlet flow, a temporal and spatial analysis of 106 hydrometric stations located across four major Arctic-draining river systems is performed to extract information regarding the timing, magnitude and volume of the spring freshet of the four largest Arctic-draining rivers; namely, the Mackenzie River in Canada, and the Ob, Yenisei and Lena rivers in Eurasia. Total annual freshwater influx to the Arctic Ocean from these basins increased by 14% during 1980-2009. Despite freshet volume displaying a net increase, its proportional contribution to annual flow has decreased. In fact, rising winter, spring and fall discharge proportions, combined with lower peak freshet magnitudes, potentially increased freshet durations, and lower summer proportions indicate a shift towards flatter, more gradual annual hydrographs with earlier pulse onsets. Discharge assessed on a sub-basin level during 1962-2000 and 1980-2000 reveals regional differences in trends, with higher-relief drainage areas displaying the strongest trends. Sub-basin trends generally agree with those at the outlets, particularly in sub-basins without upstream flow regulation. Flow regulation has had a greater impact on observed trends in freshet volume compared to peak freshet magnitude. Timing measures are found to be strongly linked to spring temperatures. Volume relationships are also apparent with winter precipitation, however, these are less distinct. Moreover, flow regulation appears to suppress climatic drivers of freshet volume but has a lesser effect on timing measures. Significant relationships are found with several major atmospheric and oceanic teleconnections indices. This study provides valuable information regarding the dominant controls of freshet generation, whilst highlighting potential impacts of freshet variability on the freshwater balance of the Arctic Ocean. / Graduate / 0388 / 0368 / roxannea@uvic.ca

Sporadic reports of significant under-ice phytoplankton production indicate a critical knowledge gap of a key component of the Arctic ecosystem. In this thesis I examine the following research objectives in an effort to improve the understanding of under-ice phytoplankton production: (1) to determine the biophysical processes controlling the timing of under-ice phytoplankton production, and (2) to compare and contrast both the timing of the under-ice bloom and the controlling processes between multiple years of data. Data for objective (1) were collected during the three-year Arctic-ICE field campaign (2010-2012) near Resolute Bay, NU in the central Canadian Arctic. Additional data from the region were collected from open source databases and peer-reviewed literature for a dataset that spanned from early 1960 to the present, supporting the analysis to meet objective (2). Two separate under-ice phytoplankton blooms were observed during the three-year Arctic-ICE campaign. It was found that phytoplankton blooms conformed well to the critical depth hypothesis in the Canadian Archipelago under first-year ice, where snow and ice melt both increased light transmission and shoaled the surface mixed layer which, in turn, placed phytoplankton within a favourable light environment for positive net production underneath the ice cover. Factors such as timing of melt water drainage and water column mixing greatly affected bloom onset. From the historical analyses, I was able to show that under-ice phytoplankton blooms have regularly occurred under landfast ice from at least the 1960’s. Significant correlations between the timing of bloom onset with melt onset related variables (i.e., air temperature reaching 0 ºC and complete snow melt) suggested a strong link to climate change. In fact, the ii analysis supported that since the mid 1990s bloom onset has been occurring earlier, and is likely related to decreasing trends in day of complete snow melt, maximum ice thickness, and snow depth. Overall, this thesis has helped improve our understanding of the under-ice spring phytoplankton bloom, showing that under-ice production has been a regular occurrence in the Canadian Arctic. The results also support that timing of the spring phytoplankton blooms could be shifting earlier in response to the warming Arctic and its changing icescape. Such a shift could also have important consequences on the Arctic marine food web, influencing the transfer of energy through the food chain. Therefore, it is of utmost importance to continue future observational programs of the under-ice pelagic environment focussed on the late spring melt period to better understand how the system could change with further perturbations.

Due to the nature of the regional geology and the bitumen extraction process, the post-mined landscape of Canada’s oil sands region will have a much higher concentration of dissolved salts than it did prior to mining. As a result, naturally saline wetlands may constitute appropriate reclamation targets and knowledge of saline wetland hydrology can provide important clues to their form and function. Furthermore, the presence of saline discharge features in the Athabasca oil sands region (AOSR) provides an opportunity to study more closely the nature of groundwater flow in a region of considerable hydrogeologic complexity, including the origin and flow history of brines and the link between springs, subsurface wastewater containment and surface water quality. A low-flow saline-spring fen peatland located adjacent to a proposed in-situ oil extraction facility was examined south of the oil sands hub of Fort McMurray, Alberta. Hydrologically disconnected from underlying Devonian deposits that are a typical source of salinity, a saline groundwater plume originating from a Lower Cretaceous aquifer (the Grand Rapids Formation) was identified as a likely source for the accumulation of Na+ (mean of 6,949 mg L-1) and Cl- (mean of 13,766 mg L-1) in fen groundwater. Considerable spatial variability in ground and surface water salinity was observed, with the concentration of dissolved salts decreasing by an order of magnitude in the direction of flow. A sharp decrease in near-surface salinity was found along the entire perimeter between the fen and adjacent freshwater wetlands. Patterns in deep groundwater flux were difficult to interpret due to possible inaccuracies associated with the piezometer network (e.g., time-lag errors in low hydraulic conductivity substrates), and rates of groundwater input were estimated to be small (< 1 mm over a season) due to the low conductivity of the underlying mineral till (5.5x10-7 cm s-1). Water table dynamics were exaggerated in response to wetting and drying for both study seasons and the fen’s small subsurface storage capacity was readily exceeded under periods of sustained rainfall. The large pond network functioned as an effective transmitter of surface water during periods of high water table but was a sink of groundwater during dry periods due to high rates of evaporation. Despite flooding conditions observed in 2012, groundwater exchange between the fen and adjacent wetlands was low and the rough microtopography worked to detain surface waters and restrict runoff in the fen’s lower reaches. Together these mechanisms worked to isolate the saline fen and restrict the flux of saline waters into the surrounding landscape. Elevated concentrations of dissolved salts in nearby wetland and river systems indicates that influence of saline discharge is not solely restricted to the region’s major river systems. The flux of salt from saline wetlands may play an important role in the overall water quality of groundwater and receiving water bodies (e.g., nearby river systems). The geochemical signature of fen groundwater points to halite as a source of salinity, as indicated by Cl-/Br- ratios in excess of 7,000. This is in contrast to what has been observed for regional formation brines that are typically related to evaporated seawater. Isotopic evidence and relatively low salinities compared to springs in the Wood Buffalo region suggests that fen discharge water may be significantly diluted as a result of mixing with freshwater sources. The contribution of evaporite to discharge water may be coming from somewhere deeper and further south in the basin. This has important implications for the disposal of wastewater by deep well injection, as disposal zones may be hydrologically linked to near-surface aquifers and discharge features well beyond the immediate production and storage area.

After successfully overthrowing Hosni Mubarak and his government in 2011, protestors rejoiced in long-repressed nationalist fervor, hopeful for the bright future that was sure to follow. Today, three years since the triumph, political inclusion and greater economic opportunity have not arrived. Throughout this transition process, the Egyptian economy has soured, and Egyptians have begun to feel nostalgia for the days of Mubarak’s regime when political stability, albeit repressive, had at least been accompanied by economic stability. This paper seeks to discover the root causes of poor economic performance in Egypt’s recent history, examine historical cases in which governments successfully overcame similar economic hardships, and propose feasible institutional reforms and recommendations to revive Egypt’s domestic economy in light of the country’s current political landscape.

Thesis (M.S.)--University of Missouri-Columbia, 2007. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on January 16, 2008) Includes bibliographical references.

Thesis (MS)--Montana State University--Bozeman, 2009. / Typescript. Chairperson, Graduate Committee: Richard E. Engel. Includes bibliographical references (leaves 86-89).

Thesis (M.A.)--University of Michigan, 1941. / Typescript. Includes bibliographical references (leaves 105-106).

Thesis (M.A.)--University of Michigan, 1941. / Typescript. Includes bibliographical references (leaves 105-106).

Thesis (Ph.D.)--Montana State University--Bozeman, 2004. / Typescript. Chairperson, Graduate Committee: Catherine A. Zabinski. Includes bibliographical references (leaves 95-103).