Because magnesium alloy tube has good formability at elevated temperature, uniaxial tensile tests were employed to evaluate the warm properties of AZ31 magnesium alloy. After that, this paper has designed and manufactured a hydraulic bulge warm forming machine which can be used to experiment with fixed tube length. Using this testing machine, the experiments of hydraulic bulge forming of AZ31 magnesium alloy and 6061 aluminum alloy tube at elevated temperatures were carried out. According to experimental results, the hydraulic bulge forming properties of tubes at different temperatures are discussed.

This thesis examines the influence of large woody debris (LWD) on the physical habitat of British headwater streams. The distribution and density of LWD accumulations throughout catchments is considered using data from the River Habitat Survey (RHS) and more detailed catchment scale surveys. The effect of accumulations of LWD on stream hydraulics and physical habitat at a reach scale is examined using transect based measurements of depth and velocity over a range of discharges before and after LWD removal for two reaches, measurement of reach average hydraulic parameters for 25 reaches with differing levels of LWD and the application of the Aggregated Dead Zone (ADZ) and Physical Habitat Simulation (PHABSIM) models. The RHS and catchment scale surveys showed that LWD accumulations exhibit systematic patterns in abundance within catchments, smaller streams having a higher density of LWD and a greater number of LWD accumulations. The most hydraulically active type of LWD accumulations were found to reduce flow velocity by an average of 55%, increase channel roughness by 149% and increase depth by 165%. This impact was, however, found to vary with discharge. Application of the Aggregated Dead Zone (ADZ) model showed that LWD increases the volume of ADZ, which may indicate greater ecological refuge potential. Using the Physical Habitat Simulation (PHABSIM) model, it was found that LWD improved habitat quality and overall habitat diversity.

Over the past century, Manitoba has promoted the construction of hydroelectric dams as a means of producing energy. These projects are produced on Indigenous territory and bring these communities into direct conflict with the province and Manitoba Hydro. Recently, Manitoba Hydro has promoted partnerships with affected First Nations. These partnerships provide communities the “opportunity” to purchase shares of the dams with the goal of gaining profits. Partnerships have been established for two projects as a means of suggesting social licence. Social licence is an informal licence provided by a community to show support and consent for a project in their area. A progressive definition of social licence is when communities provide “free, prior, and informed consent.” Partnership agreements in northern Manitoba do not provide social licence, as the communities involvement in the project, and the means by which the partnership is established do not provide “free, prior, and informed consent.” / October 2015

Rural areas of Cameroon have limited to no availability of grid-supplied electricity, however many locations have significant hydro potential. Pico hydro (less than 5 kW generation capacity) has been identified as a promising means for rural electrification. Tests of previously implemented designs and field research in Cameroon were conducted to contextualize the design process. Field research involved end-user and artisan interviews, market research, site investigations, and artisan collaboration. Findings were used to select an axial flow propeller for the improved turbine. Detailed design used turbomachinery theory towards the development of a locally manufactured low head pico hydro turbine for rural electrification. A propeller turbine with complex blade geometries was designed but simplified to incorporate flat blade geometries to better suit the local manufacture capabilities. A prototype turbine was built and tested. The flat blade propeller turbine performed reasonably well, but was unable to achieve desired power generation targets with predefined head and flow rate conditions.

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

Research Project (M.B.A.) - Simon Fraser University, 2006. / Theses (Faculty of Business Administration) / Simon Fraser University. MBA-MOT Program. Senior supervisor : Dr. Sudheer Gupta. Also issued in digital format and available on the World Wide Web.

Thesis (M.S.)--University of Wisconsin--Madison. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 82-83).

Meandering rivers provide fresh water and important aquatic ecosystem services, yet at the same time induce flood and erosion hazards. In the face of ongoing development pressure and changing climate, growing concern for meandering rivers has increased the demand to model accurately the flow and predict the sediment transport in a meandering river channel. Calibration and validation of these models based on comparable field-based data, as opposed to laboratory-scale experimental data, may decrease uncertainty and improve understanding of complex flow structures in natural meandering rivers. In this thesis, spatially intensive field data are utilized to develop appropriate calibration and validation methods for 3D meandering river models. Validated models are then applied to the study of morphodynamic processes and the influence of channel change on fish habitat availability in meandering rivers. This study presents a novel methodology for use of three-dimensional (3D) velocity for improved calibration of a 3D hydro-morphodynamic model. A natural tortuously meandering river was simulated using the Delft3D hydrodynamic model. A spatially intensive acoustic Doppler current profiler (ADCP) survey was conducted throughout the study river, providing fully 3D distributed velocities for model calibration. For accurate and realistic comparison of the fully 3D predicted and measured velocities, an algorithm was developed to match the location of each ADCP bin with 3D model grid points. The results suggest that different calibration approaches can result in different calibration parameterizations whose simulated results can differ significantly. It is shown that the model which was calibrated based on the proposed 3D calibration approach had the best model performance. Depending upon the nature and objectives of the numerical modelling exercise, the results demonstrate the importance of model calibration with spatially intensive field data. Given the importance of pressure gradients in driving secondary flow, it is worth studying how the modelled flow structures in a natural river bend can be impacted by the assumption of hydrodynamic pressure. Accordingly, the performance of hydrostatic versus non-hydrostatic pressure assumption in the Delft3D hydrodynamic modelling of a tortuously meandering river was studied. An Acoustic Doppler Velocimeter (ADV) was employed to measure the 3D flow field at a section in a sharp bend of the simulated river at two different flow stages. The field-based ADV data were employed to validate the simulated hydrodynamic models. The results indicate the surprisingly superior performance of the hydrostatic over non-hydrostatic Delft3D modelling of the secondary flow. It was determined that the non-hydrostatic routine employed in Delft3D was not mass conservative, which diminished model accuracy. Despite several decades of intensive study of the morphological changes in meandering rivers, less attention has been paid to confined meanders. This thesis includes a study of the meandering behavior of a semi-alluvial cohesive bed river over a 10-year period. We employed a paired sub-reach study approach, wherein one sub-reach is freely meandering and the second adjacent sub-reach is confined by a railway embankment. Channel migration and morphological changes of the channel banks along each of these sub-reaches were analyzed by comparing the historical aerial photography, light detection and ranging (LIDAR) data, bathymetric data obtained from a total station survey, and field examination. Moreover, two different spatially intensive ADCP surveys were conducted in the study area to find the linkage between the hydrodynamics and morphological changes in the two different sub-reaches. The unconfined sub-reach displayed a typical channel migration pattern with deposition on the inner bank and erosion on the outer bank of the meander bend. On the other hand, the confined sub-reach showed greater bank instabilities than the unconfined sub-reach. In the confined sub-reach, an irregular meandering pattern occurred by the evolution of a concave-bank bench, which was caused by reverse flow eddies. The results of this study could shed light on the potential impacts of channel confinement on bank retreat and river migration in comparable case studies. It is reasonable to expect that hydro-morphodynamic processes in rivers can affect fish habitat availability and quality, but the impact of river morphological changes on fish habitat is not well studied. Herein, we investigate the impact of morphological development of a cohesive meandering creek on the quality of fish habitat available for juvenile yellow perch (Perca flavescens) and white sucker (Catostomus commersonii). A 3D morphodynamic model was first developed to simulate the hydro-morphodynamics of the study creek over a 1-year period. Total station topographic surveys were conducted to provide bathymetric change data for calibration of the morphodynamic module. Successful calibration efforts indicated that the developed model could be reasonably employed to predict the hydro-morphodynamics of the study creek. Two fish sampling surveys were carried out at the beginning and the end of the study period to determine habitat utilization of each fish species in the study reach. ANOVA multiple comparison tests indicate that morphological development of the river was a significant factor for the habitat utilization of juvenile yellow perch, whereas juvenile white sucker habitat utilization was not significantly impacted by the changes in the creek morphology. It is shown that flow depth, depth-averaged velocity, and suspended sediment transport also significantly influenced presence of the juvenile yellow perch at the 5% significant level. As for the juvenile white sucker, the only significant factor was the depth-averaged velocity. The results of the developed 3D hydro-morphodynamic model were fed into a fish habitat model. Comparison of the predicted fish habitat map of the juvenile yellow perch with the results of fish sampling surveys confirms that the habitat quality was better predicted when the impact of morphological changes was taken into account in the fish habitat modelling. The results of the proposed methodology could provide some insights into the impact of sediment transport processes on the fish community. This has important implications for effective river management.

To ensure secure geological storage of carbon dioxide it is necessary to establish the integrity of the overlying sealing rock. Seal rock fractures are key potential leakage pathways for storage systems; understanding their behaviour in the presence of CO2 under reservoir conditions is therefore of great importance. This thesis presents experimental investigations into the hydraulic behaviour of discrete fractures within low permeability seal rocks during single phase supercritical CO2 flow, under varying mechanical and thermal conditions representative of in-situ conditions. An experimental rig was designed and built to enable the controlled study of supercritical CO2 flow through 38 mm diameter samples under high pressures and temperatures. Samples are placed within a Hassler-type uniaxial pressure cell and CO2 flow is controlled via high precision syringe pumps. Flow experiments with supercritical CO2 within the pressure range 10-50 MPa were undertaken at temperatures of 38°C and 58°C with confining pressures of 35-55 MPa. The effects of stress loading and temperature change on the hydraulic properties of the fractured sample were studied; continuous differential pressure measurement enabled analysis of hydraulic response. Experiments were undertaken on a pre-existing Wissey field Zechstein Dolomite fracture and three artificial fractures (two East Brae field Kimmeridge Clay samples and one Cambrian shale quarry sample). Fracture permeabilities ranged from 8 X 10-14 m2 to 6 X 10-11 m2 with higher permeabilities observed within the harder rock samples. A broadly linear flow regime, consistent with Darcy's law, was observed in the lowest permeability sample (East Brae). A Forchheimer-type non-linear flow regime was observed in the other samples. Transmissivity variations during experiments were used to infer the mechanical impact of stress and temperature changes. An increase in effective stress resulted in transmissivity reduction, suggesting fracture aperture closure. During initial stress loading cycles, and subsequent higher temperature stress loading, a component of this transmissivity reduction was found to be inelastic, suggesting permanent modification of fracture geometry during closure. Pre- and post-experiment fracture surface characterisation provides further evidence for the occurrence of plastic deformation. Transmissivity-stress relationships were elastic during subsequent external stress-loading cycles, suggesting elastic closure and opening of fractures without additional permanent fracture geometry changes. The impact of fluid property variations on fracture hydraulic conductivity, Kfrac, was also analysed. Under constant effective stress Kfrac was found to be higher within high temperature and low fluid pressure scenarios, due to higher density/viscosity ratios. However, under constant confining pressure, fluid pressure changes are coupled both to mechanical effects (from effective stress alteration) and hydraulic effects (from viscosity variation), with opposing impacts on fracture hydraulic conductivity. At lower effective stresses mechanical effects were found to be dominant, with fluid pressure increase resulting in a notable increase to Kfrac due to aperture opening. At higher effective stresses, mechanical changes are much smaller due to increased contact area between fracture surfaces, and thus increased stiffness of fractures. Under such conditions hydraulic effects may be dominant and result in a small Kfrac reduction as fluid pressure increases, due to a reduction in the density/viscosity ratio. These results highlight that CO2 fluid property variation can have a notable influence on hydraulic conductivity under certain in-situ conditions. The single phase CO2 fracture flow experiments undertaken during this study were designed to enable a study of hydraulic and mechanical processes in isolation, without the influence of chemical processes. In-situ, the additional presence of brine and thus multiphase fluid behaviour and associated chemical processes makes the hydraulic behaviour of fractures considerably more complex. Coupled process modelling enables the relative influence of these processes to be simulated, but relies on experiments for validation. These unique experimental findings are of great value for enabling validation of such models as well as for informing analyses of geological and field studies.

No description available.