14 research outputs found
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Preliminary Study of Turbulent Flow in the Lower Plenum of a Gas-Cooled Reactor
A preliminary study of the turbulent flow in a scaled model of a portion of the lower plenum of a gas-cooled advanced reactor concept has been conducted. The reactor is configured such that hot gases at various temperatures exit the coolant channels in the reactor core, where they empty into a lower plenum and mix together with a crossflow past vertical cylindrical support columns, then exit through an outlet duct. An accurate assessment of the flow behavior will be necessary prior to final design to ensure that material structural limits are not exceeded. In this work, an idealized model was created to mimic a region of the lower plenum for a simplified set of conditions that enabled the flow to be treated as an isothermal, incompressible fluid with constant properties. This is a first step towards assessing complex thermal fluid phenomena in advanced reactor designs. Once such flows can be computed with confidence, heated flows will be examined. Experimental data was obtained using three-dimensional Particle Image Velocimetry (PIV) to obtain non-intrusive flow measurements for an unheated geometry. Computational fluid dynamic (CFD) predictions of the flow were made using a commercial CFD code and compared to the experimental data. The work presented here is intended to be scoping in nature, since the purpose of this work is to identify improvements that can be made to subsequent computations and experiments. Rigorous validation of computational predictions will eventually be necessary for design and analysis of new reactor concepts, as well as for safety analysis and licensing calculations
A study of molecular genetic alterations in epithelial ovarian cancer
SIGLEAvailable from British Library Document Supply Centre-DSC:DXN020003 / BLDSC - British Library Document Supply CentreGBUnited Kingdo
Association analysis of apolipoprotein E genotype and risk of depressive symptoms in Alzheimer's disease
Allelic variation at the A218c tryptophan hydroxylase polymorphism influences agitation and aggression in alzheimers disease
Common polymorphisms in LRP and A2M do not affect genetic risk for alzheimer disease in northern ireland
Synthesis and characterization of water-soluble phenylene-vinylene-based singlet oxygen sensitizers for two-photon excitation
Following the cognitive work analysis train of thought: exploring the constraints acting on modal shift to rail transport
Environmental concerns show that transport is responsible for almost a quarter of all greenhouse gas emissions, and it is also the fastest growing sector. Modal shift towards public transport could help slow down, or even reverse, this trend. There appear to be a number of constraints that are preventing this from happening. This paper explores the constraints to modal shift to rail transport from the perspective of cognitive work analysis, specifically the abstraction hierarchy, the contextual activity template and social organisational and cooperation analyses. Whilst these analyses may not present any new barriers, they do show how the constraints are interlinked in an explicit manner. These interrelations are important for two reasons. First, in consideration of constraint removal, one must anticipate the likely effects on the remainder of the system. Second, by linking functions and situations, new concepts of travel may be identified and explored.Practitioner Summary:The purpose of this study was to use a semi-structured approach to identifying constraints to modal shift from a variety of perspectives. It is argued that cognitive work analysis offers a new way of thinking about the modal shift problem and helps to generate new insights into potential solutions