11,498 research outputs found

    RedFeather- resource exhibition and discovery: a lightweight micro-repository for resource sharing

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    Open Educational Resources (OERs) depend on being hosted in repositories so that they can be effectively viewed, managed, searched and indexed online. Content – especially multimedia content – that is not hosted in this way has no metadata and is effectively dark to the wider community. Similarly content that is not described properly, and with appropriate licenses, is of limited use. This is a challenge for small-scale contributors, such as individuals and small projects, as the overhead of setting up and administrating a content repository can be prohibitive.In this paper we propose RedFeather, a micro-repository, as a solution to this problem. RedFeather is a simple and straightforward server-side tool that requires zero to little configuration, but that provides the core functionality of a fully-fledged OER repository, including: resource pages with inline preview, a resource manager with streamlined workflow, and views of the resource in OER critical formats (including RDF, JSON, and RSS). RedFeather is fully customizable, with a flexible plugin architecture and configurable templates, but also works without any customization as a single php script file uploaded to a web server. The goal of a micro-repository like RedFeather is both to enable small-scale contributors to easily join the OER community, and to act as a intermediate step for larger contributors beginning a collection, or requiring a temporary home for their resources while a more substantial repository is developed. Our hope is that by lowering the barriers to participation, RedFeather can help the OER community to take advantage of the long tail of small to medium sized content creators

    Assessing the potential for suffusion in sands using x-ray micro-CT images

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    Internal erosion is a major safety concern for embankment dams and flood embankments and is the focus of much research internationally. Suffusion is a mechanism of internal erosion which affects gap-graded or broadly graded cohesionless soils and is characterised by selective removal of fine material, leaving behind a coarse material with increased hydraulic conductivity. Early studies on suffusion proposed design criteria based on laboratory testing, and presented conceptual models to explain the results in terms of grain-scale behaviour. The study by Kenney & Lau (1985) identified three criteria for suffusion: 1 – Fine particles must be free to move (mechanical criterion); 2 – Fine particles must be small enough to fit through the void space between coarse particles (geometric criterion); 3 – Fluid flowing through the void space must have sufficient velocity to transport the fine particles (hydraulic criterion). Recent studies have examined the first two criteria using grain-scale models with idealised particles, including analytical models and discrete element models (DEM) with circular or spherical particles. This thesis presents a new methodology, using non-destructive 3D imaging (micro-CT) to characterise the internal microstructure in physical specimens of sands and glass beads. This methodology involved the development of innovative image processing and numerical techniques to quantify unstable particle assemblies and to measure particle size distributions and void constriction size distributions. The new method was validated and was shown to produce good agreement with existing methods for idealised particle configurations, however the results for real sand specimens provided new insights into the effects of particle shape, particle size distribution and density on void constriction sizes. Furthermore, the 3D images of real specimens have provided new insights into the appropriateness of existing conceptual models for gap-graded particle structures. These results were used to critically examine and evaluate existing mechanical and geometric criteria for suffusion. The 3D images showed, qualitatively, that the void structures in sands varied significantly from those in porous rocks – which had been the basis for the majority of existing grain-scale fluid flow models. To examine this issue quantitatively, computational fluid dynamics (CFD) simulations were performed within the 3D images of sands and glass beads, in parallel to laboratory permeameter tests on the same materials. The results presented in this thesis provided entirely new insights into the patterns of fluid flow in sands, they allowed correlations to be made between fluid flow and void constriction sizes and also showed how local velocities varied from volume-average discharge and seepage velocities. This study provides new information to support, clarify and improve upon the current understanding of suffusion, filtration and seepage flows in sands. The detailed methodology and results also highlight issues of great importance to future micro-scale modelling of these phenomena.Open Acces

    The effects of interpersonal communication style on task performance and well being (A Thesis submitted for the degree of Doctor of Philosophy)

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    This thesis is based around five studies examining the psychology of interpersonal communication applied to organizational settings. The studies are designed to examine the question of how the way that people in positions of power in organizations communicate with subordinates, affects various measures of health, well-being and productivity. It is impossible to study modern organisational communication without recognising the importance of electronic communication. The use of e-mail and other forms of text messaging is now ubiquitous in all areas of communication. The studies in this thesis include the use of e-mail as a medium of communication and examine some of the potential effects of electronic versus face-to-face and verbal communication. The findings of the studies support the basic hypothesis that: it is not what is said that matters but how it is said. The results showed that an unsupportive, formal, authoritarian style of verbal or written communication is likely to have a negative effect on health, well-being and productivity compared with a supportive, informal and egalitarian style. There are also indications that the effects of damaging communications may not be confined to the initial recipient of the message. Organizational communication does not take place in a vacuum. Any negative consequences are likely to be transmitted by the recipient, either back to the sender or on to other colleagues with implications for the wider organisational climate. These findings are based on communications that would not necessarily be immediately recognised as obviously offensive or bullying, or even uncivil. The effects of these relatively mild but unsupportive communications may have implications for the selection and training of managers. In the final section of the thesis there is a discussion of how examples of various electronically recorded messages might be used as training material

    A Thesis on the Formulation of a Manual on Education Development/Change

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    Statistical sampling for soil mapping surveys

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    Isolation of a new paramyxovirus

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    The Cultural Mosaic Under the Tesserae: Local Identity in the Iconography and Compositions of Roman Floor Mosaics

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    This thesis examines the way the medium of mosaics was adapted locally by the cities of Antioch (modern Antakya, Turkey) and Thysdrus (modern El Djem, Tunisia) during the second and third centuries CE. Compositional differences indicate different conceptions of the medium and locally specific iconography draws on viewers’ local knowledge and experience to situate the city and its inhabitants within the broader context of the Roman empire
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