Heat and fluid flow in a scraped-surface heat exchanger containing a fluid with temperature-dependent viscosity

Scraped-surface heat exchangers (SSHEs) are extensively used in a wide variety of industrial settings where the continuous processing of fluids and fluid-like materials is involved. The steady non-isothermal flow of a Newtonian fluid with temperature-dependent viscosity in a narrow-gap SSHE when a constant temperature difference is imposed across the gap between the rotor and the stator is investigated. The mathematical model is formulated and the exact analytical solutions for the heat and fluid flow of a fluid with a general dependence of viscosity on temperature for a general blade shape are obtained. These solutions are then presented for the specific case of an exponential dependence of viscosity on temperature. Asymptotic methods are employed to investigate the behaviour of the solutions in several special limiting geometries and in the limits of weak and strong thermoviscosity. In particular, in the limit of strong thermoviscosity (i.e., strong heating or cooling and/or strong dependence of viscosity on temperature) the transverse and axial velocities become uniform in the bulk of the flow with boundary layers forming either just below the blade and just below the stationary upper wall or just above the blade and just above the moving lower wall. Results are presented for the most realistic case of a linear blade which illustrate the effect of varying the thermoviscosity of the fluid and the geometry of the SSHE on the flow

Nutrition tactics to improve post-exercise recovery

Sport drinks contain carbohydrate that can be used as fuel during exercise. My research shows that sports drinks containing both the carbohydrate glucose and fructose are more effective for this purpose than the same amount of carbohydrate as just glucose. They also result in less stomach complaints. Protein ingestion provides the building blocks for muscle recovery and growth. Our data show that athletes typically eat a lot of protein during breakfast, lunch and dinner, but that little protein is ingested prior to sleep. We also demonstrated that supplementing protein before sleep improves overnight muscle recovery

Paleoglaciological dynamics in northern Manitoba and the subglacial bed mosaic

During the last glacial maximum (LGM), some 20 ka ago, northern Manitoba was situated beneath 3 to 4.5 km of ice, on the outer fringe of a major ice spreading center of the Laurentide Ice Sheet. The region has also been affected by major paleoglaciological changes linked to multiple source areas, migration of ice centres, and ice-sheet thickening/thinning over multiple glacial cycles. The net effect of this evolution is a very complex geological record, which has major implications for ice-sheet reconstructions and drift prospecting. Theory-based hypothesis for the region suggest initial advance-phase deposition was followed by either net-erosive or cold-based conditions for much of the glacial cycle. In contrast, observation-based reconstructions of ice-sheet behaviour consider the glacial landscape to have been predominately formed by near-complete overprinting during warm-based deglaciation. Some complexity has been recognized in sediment-landform records, but new insights into glacial dynamics and sediment-landscape evolution are needed. Systematic mapping (remote-sensing) and fieldwork (ice-flow indicators, till composition, ground truthing) in northeastern Manitoba has led to the recognition of spatio-temporal variability in landscape (streamlined-landform event-flowsets) and landform (micro and meso-scale ice-flow indicator records) and till composition inheritance. In particular, analysis of the spatio-temporal characteristics of the subglacial landscape led to the recognition of disjoint zones with internally-consistent assembly histories – termed glacial terrain zones (GTZ). These GTZ were then classified as (1) relict-glacial, (2) palimpsest, or (3) deglacial in nature. Generally, (1) is interpreted as pre-LGM, (2) may include pre-LGM terrain but also LGM to early deglaciation (ice margin still far from study area; ice sheet thinning phase) and (3) was formed during the final ice retreat phase. The resultant surface till composition within relict and palimpsest GTZs is a spatial mosaic interpreted to reflect variable intensities in modification (overprinting) and preservation (inheritance) of a predominately pre-deglacial till sheet. In these regions, streamlined landforms parallel to a known deglacial ice-flow orientation were unable to overprint the underlying inherited glacial sediment composition. Secondly, field investigations (sedimentology, clast fabrics, till composition, near-surface S-wave seismic surveys) have characterized the widespread Rogen moraine terrain. These transverse subglacial ridges are spatially associated with streamlined landforms, are situated on regionally low-lying terrain without topographic constraints and may have small bedrock ‘knob’ obstacles at their up-ice base. This thesis assesses Rogen moraine formation hypotheses within the new paleoglaciologic context of northern Manitoba, favours an instability mechanism for formation, and provides important field data against which further formation hypothesis should be tested. The main insight of this study is not a detailed reconstruction (local history), but rather a series of forms of evidence suggesting that the glacial history of the region is one of prevailing patchy low-erosion conditions which favored preservation of a fragmentary record of non-coeval and sometimes contrasting warm-based (more dynamic) conditions. Despite being near a thick inner-core region of the Laurentide Ice Sheet, where basal conditions are generally considered stable and meltwater availability is low, the hard-bed study area was subject to local spatio-temporal shifts in subglacial conditions that led to generation of a complex palimpsest glacial landscape. Spatial differences in the preservation of older streamlined landforms, variably drumlinized Rogen moraine and the concentrations of inherited subglacial detritus all culminate in a hypothesis that suggests the subglacial landscape was continually evolving and subject to spatio-temporal variations in the intensity of ice-bed processes throughout the last glaciation (subglacial bed mosaic). Based on the new glacial history, and a general lack of ice-marginal landsystems, most warm-based ice-flow phases likely occurred near LGM – with only weak overprinting during late deglaciation. The idea of landform generation at patches within a transient subglacial bed mosaic now allows for a close association between subglacial drumlins and Rogen moraine ridges, that may have formed by disconnected and not necessarily coeval or related processes. This mosaic, of slow to non-flowing basal ice (‘sticky regions’) and wet-based flowing-ice patches, also helps to explain preservation of immature landforms (Rogen moraine) and relict or palimpsest terrain. Sticky regions may have formed by at least two different mechanisms: localized heterogeneous switches in basal thermal regime (frozen-bed patches), or within a warm-based subglacial environment from wet to stiff, dewatered till

Identity and Paternity Testing of Cattle:Application of a Deoxyribonucleic Acid Profiling Protocol

We have applied DNA profiling for identity and parentage studies of cattle using a standardized procedure based on synthetic micro- and minisatellite multilocus core probes in Southern blot hybridization assays. This protocol is useful for paternity analysis of cattle and for real case work (e.g., identity and paternity disputes).</p