Excess water in prairie soils: land management in an uncertain climate

Non-Peer Reviewe

The complexity of soil landscapes: variability from the macro-scale to the micro-scale

Non-Peer Reviewe

Advanced solar concentrator mass production, operation, and maintenance cost assessment

The object of this assessment was to estimate the costs of the preliminary design at: production rates of 100 to 1,000,000 concentrators per year; concentrators per aperture diameters of 5, 10, 11, and 15 meters; and various receiver/power conversion package weights. The design of the cellular glass substrate Advanced Solar Concentrator is presented. The concentrator is an 11 meter diameter, two axis tracking, parabolic dish solar concentrator. The reflective surface of this design consists of inner and outer groups of mirror glass/cellular glass gores

Laboratory scale experiments with water surface waves

The thesis presents the development, implementation and results of two series of experiments, at large and small scale, for the study of surface gravity waves. A number of measurement techniques are developed and implemented to capture space and time evolution of waves on a water surface in gravity, gravity-capillary and capillary ranges with the purpose to study the statistics of wave turbulence in terms of frequency and wave number spectra.The first series of experiments was conducted in a large wave tank of size 12 m x 6 m x 1.6 m filled with water to a depth of 0.9 m. A wave maker comprised of eight panels is controlled by a computer to generate waves at typically two frequencies; these waves are directed at different angles. Surface elevation of the resulting turbulent wave field is measured via capacitance wire probes and a fluorescent laser technique that is capable of capturing wave profiles at sufficient frame rate to access both wavenumber and frequency statistics. Following the processing of these data a comprehensive set of results describe characteristics of the life cycle of the experiment including the rise of the wave field to its statistically stationary state and the decay of the regime after energy pumped into the system from the wave maker has ceased.The first series of experiments was conducted in a large wave tank of size 12 m x 6 m x 1.6 m filled with water to a depth of 0.9 m. A wave maker comprised of eight panels is controlled by a computer to generate waves at typically two frequencies; these waves are directed at different angles. Surface elevation of the resulting turbulent wave field is measured via capacitance wire probes and a fluorescent laser technique that is capable of capturing wave profiles at sufficient frame rate to access both wavenumber and frequency statistics. Following the processing of these data a comprehensive set of results describe characteristics of the life cycle of the experiment including the rise of the wave field to its statistically stationary state and the decay of the regime after energy pumped into the system from the wave maker has ceased.Across both series of experiments the implementation of data acquisition techniques forms a significant contribution to the work undertaken and a comprehensive set of tools for measurement and analysis of data from surface waves is developed

Assessing land use influences on the expression of soil iron hydric indicators

Non-Peer ReviewedHydric soil features develop over frequent and prolonged saturation. This study investigated the influence of land use on the expression Fe related hydric indicators for the overarching goal of being able to delineate Prairie Pothole Region wetlands where native species have been significantly disturbed. Initial soil classification of wetland pits showed differences among the land uses. Further laboratory analysis looking at free extractable Fe (Dithionite-Fe extraction) and magnetic susceptibility showed little significant differences among the land uses. Further study is required to determine if interacting affects among other hydric indicators, including clay leaching and carbon contents, significantly differ among land uses

Gross N-cycling rates in ephemeral wetlands

Non-Peer ReviewedEphemeral wetlands or depressions in hummocky landscapes have high levels of C, N, and soil moisture, often leading to high nutrient cycling activity. However, measuring soil nitrate and ammonium pools is typically a poor indication of N-cycling activity or of the soil N that is available for other processes such as N2O emissions. This study used stable 15N isotope dilution techniques in cultivated and uncultivated ephemeral wetlands in central Saskatchewan to quantify land use effects on gross mineralization and nitrification rates. In-field incubation experiments were repeated in early May, mid-June and late July. There was a clear land use effect on inorganic soil N levels, with significantly less NH4+ and more NO3- in the cultivated wetland soils. However, the rates of NH4+ mineralization and NO3 - nitrification were similar for both land uses, indicating similar substrate availability but different N-consuming processes. Both N pools turned over in as little as 1-2 d, highlighting the ineffectuality of measuring inorganic N pools as a predictor for N availability in these soils

Benefits and implications of agricultural drainage in southeast Saskatchewan

Non-Peer Reviewe

Response of PPR soils to changing groundwater and salinity: a microcosm study of greenhouse gas emissions

Non-Peer Reviewe

Study on the neuronal circuits implicated in postural tremor and hypokinesia

The effect of various tegmentary lesions at the level of the pontomesenchphalon in monkeys on motor function was observed. The importance of the monoaminergic mechanisms of the brainstem is discussed. The results also show the importance of the descending tegmentary rubral system and the rubroolivocerebellar circuit in controlling peripheral motor activity. The destruction of the sensory motor cortex proves to be a more effective way of eliminating spontaneous or harmaline induced tremor than the complete interruption of the pyramidal system on the level of the cerebral peduncle