59 research outputs found

    Modeling the Influence of a Variable Permeability Inclusion on Free-Surface Flow in an Inclined Aquifer

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    The interaction of sub-surface, gravity-driven flows with inclusions of different permeabilities are investigated theoretically using a model that exploits the relative shallowness of the motion. Numerically computed solutions for steady motion around cylindrical inclusions reveal a range of behaviors dependent on the ratio of the interior to exterior permeability and a dimensionless flow parameter that measures the far-field thickness to the product of the gradient of the slope down which the fluid flows and the width of the inclusion. When the inclusion is relatively narrow, the depth of the flow is little changed from its far-field value and the fluid is focused into inclusions of higher permeability and deflected around those of lower permeability. However, if the inclusion is relatively wide then three qualitatively different regimes emerge, dependent on the ratio of permeabilities. When the interior and exterior permeabilities are similar, then negligible deviation of the flow occurs apart from within thin transition layers at the boundary of the inclusion. When the permeabilities differ significantly, the flow forms deep ponds at either the upstream or downstream boundary of the inclusion for relatively low or high permeability inclusion, respectively, which arise due to deflection or focusing. In each case, asymptotic relationships are derived between the depth of the flow and the parameters. Inclusions of differing cross-section are also analyzed numerically and analytically to draw out the interplay between adjustment, deflection and focusing

    Stationary shapes of deformable particles moving at low Reynolds numbers

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    Lecture Notes of the Summer School ``Microswimmers -- From Single Particle Motion to Collective Behaviour'', organised by the DFG Priority Programme SPP 1726 (Forschungszentrum J{\"{u}}lich, 2015).Comment: Pages C7.1-16 of G. Gompper et al. (ed.), Microswimmers - From Single Particle Motion to Collective Behaviour, Lecture Notes of the DFG SPP 1726 Summer School 2015, Forschungszentrum J\"ulich GmbH, Schriften des Forschungszentrums J\"ulich, Reihe Key Technologies, Vol 110, ISBN 978-3-95806-083-

    Prescription for nursing informatics in pre-registration nurse education.

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    Nurses need to be able to use information and communications technology not only to support their own practice, but also to help their patients make best use of it. This article argues that nurses are not currently adequately prepared to work with information and technology through their pre-registration education. Reflecting the lack of nursing informatics expertise, it is recommended that all pre-registration nursing programmes should have access to a nursing informatics specialist. A prescription to meet the informatics needs of the newly qualified nurse is proposed. This places the areas that need to be included in pre-registration education into broad groups that both articulate the competencies that nurses need to develop, and indicate why they are needed, rather than providing context-free checklists of skills. This is presented as a binary scatter chart with two axes, skill to knowledge and technology to information

    A Comprehensive Workflow for General-Purpose Neural Modeling with Highly Configurable Neuromorphic Hardware Systems

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    In this paper we present a methodological framework that meets novel requirements emerging from upcoming types of accelerated and highly configurable neuromorphic hardware systems. We describe in detail a device with 45 million programmable and dynamic synapses that is currently under development, and we sketch the conceptual challenges that arise from taking this platform into operation. More specifically, we aim at the establishment of this neuromorphic system as a flexible and neuroscientifically valuable modeling tool that can be used by non-hardware-experts. We consider various functional aspects to be crucial for this purpose, and we introduce a consistent workflow with detailed descriptions of all involved modules that implement the suggested steps: The integration of the hardware interface into the simulator-independent model description language PyNN; a fully automated translation between the PyNN domain and appropriate hardware configurations; an executable specification of the future neuromorphic system that can be seamlessly integrated into this biology-to-hardware mapping process as a test bench for all software layers and possible hardware design modifications; an evaluation scheme that deploys models from a dedicated benchmark library, compares the results generated by virtual or prototype hardware devices with reference software simulations and analyzes the differences. The integration of these components into one hardware-software workflow provides an ecosystem for ongoing preparative studies that support the hardware design process and represents the basis for the maturity of the model-to-hardware mapping software. The functionality and flexibility of the latter is proven with a variety of experimental results
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