736 research outputs found

    Tropospheric reactions of the haloalkyl radicals formed from hydroxyl radical reaction with a series of alternative fluorocarbons

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    In the present assessment, the hydrogen containing halocarbons being considered as alternatives to the the presently used chlorofluorocarbons are the hydrochlorofluorocarbons (HCFCs) 123 (CF3CHCl2), 141b (CFCl2CH3), 142b (CF2ClCH3), 22 (CHF2Cl) and 124 (CF3CHFCl) and the hydrofluorocarbons (HFCs) 134a (CF3CH2F), 152a (CHF2CH3) and 125 (CF3CHF2). All of these HCFCs and HFCs will react with the hydroxyl (OH) radical in the troposphere, giving rise to haloalkyl radicals which then undergo a complex series of reactions in the troposphere. These reactions of the haloalkyl radicals formed from the initial OH radical reactions with the HCFCs and HFCs under tropospheric conditions are the focus here

    Roger Atkinson’s reflections on David Hillson’s Risk Doctor briefing

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    Roger Atkinson's reflections on David Hillson's Risk Doctor briefin

    Information system's project management and the phenomenon of trust.

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    The aim of this research was to investigate how the continual low success rate of IS projects could be improved through an evaluation of success and failure factors. A literature review revealed a comprehensive but uncoordinated history of research into the identification of the critical factors. This proved to be inconclusive, but did indicate that project management contributed more to the failures than the technology. A model for expressing the complexity of IS project environments is proposed to aid project teams with their strategy. Also, the criteria for measuring success of both project managemenat nd IS projects has been extended. Although many disciplines had considered trust as a success factor, this was missing within the domain of project management. To examine the effect of trust in an IS project environment a game termed Project Paradox was designed and run. A lack of trust was found to be compounded by conflicting objectives inherent within IS projects. It is recommended that the issues relating to trust should be considered and managed as an integral part of a risk analysis. To enable this to be realised in practice a framework for a Trust Audit is proposed. The thesis concludes with a number of research initiatives aimed at improving the success rate of IS projects

    Local density of states of a d-wave superconductor with inhomogeneous antiferromagnetic correlations

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    The tunneling spectrum of an inhomogeneously doped extended Hubbard model is calculated at the mean field level. Self-consistent solutions admit both superconducting and antiferromagnetic order, which coexist inhomogeneously because of spatial randomness in the doping. The calculations find that, as a function of doping, there is a continuous cross over from a disordered ``pinned smectic'' state to a relatively homogeneous d-wave state with pockets of antiferromagnetic order. The density of states has a robust d-wave gap, and increasing antiferromagnetic correlations lead to a suppression of the coherence peaks. The spectra of isolated nanoscale antiferromagnetic domains are studied in detail, and are found to be very different from those of macroscopic antiferromagnets. Although no single set of model parameters reproduces all details of the experimental spectrum in BSCCO, many features, notably the collapse of the coherence peaks and the occurence of a low-energy shoulder in the local spectrum, occur naturally in these calculations.Comment: 9 pages, 5 figure

    Information system's project management and the phenomenon of trust

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    The aim of this research was to investigate how the continual low success rate of IS projects could be improved through an evaluation of success and failure factors. A literature review revealed a comprehensive but uncoordinated history of research into the identification of the critical factors. This proved to be inconclusive, but did indicate that project management contributed more to the failures than the technology. A model for expressing the complexity of IS project environments is proposed to aid project teams with their strategy. Also, the criteria for measuring success of both project managemenat nd IS projects has been extended. Although many disciplines had considered trust as a success factor, this was missing within the domain of project management. To examine the effect of trust in an IS project environment a game termed Project Paradox was designed and run. A lack of trust was found to be compounded by conflicting objectives inherent within IS projects. It is recommended that the issues relating to trust should be considered and managed as an integral part of a risk analysis. To enable this to be realised in practice a framework for a Trust Audit is proposed. The thesis concludes with a number of research initiatives aimed at improving the success rate of IS projects.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

    Information system's project management and the phenomenon of trust

    Get PDF
    The aim of this research was to investigate how the continual low success rate of IS projects could be improved through an evaluation of success and failure factors. A literature review revealed a comprehensive but uncoordinated history of research into the identification of the critical factors. This proved to be inconclusive, but did indicate that project management contributed more to the failures than the technology. A model for expressing the complexity of IS project environments is proposed to aid project teams with their strategy. Also, the criteria for measuring success of both project managemenat nd IS projects has been extended. Although many disciplines had considered trust as a success factor, this was missing within the domain of project management. To examine the effect of trust in an IS project environment a game termed Project Paradox was designed and run. A lack of trust was found to be compounded by conflicting objectives inherent within IS projects. It is recommended that the issues relating to trust should be considered and managed as an integral part of a risk analysis. To enable this to be realised in practice a framework for a Trust Audit is proposed. The thesis concludes with a number of research initiatives aimed at improving the success rate of IS projects.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

    An observational study of the ozone dilution effect: Ozone transport in the austral spring stratosphere

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    In a previous observational analysis, Atkinson et al (1989) ascribed a sudden decrease in Southern Hemisphere midlatitude total ozone during December 1987 to an 'ozone dilution effect' brought about by the breakup of the polar stratospheric vortex at that time. A question alluded to but unanswered by that study was the degree to which the observed total ozone decrease might have been caused by the quasi-horizontal equatorward transport of 'ozone hold' air from within the vortex, and to what degree by the vertical advection from lower levels of air naturally low in ozone, a dynamical adjustment process which must accompany the equatorward outbreak of a discrete high-latitude airmass. In the present study, analyses of Ertel potential vorticity, TOMS total ozone, and SAGE and ozone sonde vertical profile data are employed using a novel technique to examine the 1987 event in greater detail, to answer this question. Recent progress is then reported in refining the technique and extending the investigation to examine the dynamical evolution of the austral spring stratosphere during other recent years, to shed more light on the precise nature, frequency, and severity of such 'ozone dilution' events, and the effect that this process may have on long term ozone behavior in the Southern Hemisphere

    Granuloma debridement and the use of an injectable calcium phosphate bone cement in the treatment of osteolysis in an uncemented total knee replacement

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    Polyethylene particulate debris-induced periprosthetic osteolysis is a known complication of knee arthroplasty surgery, and may result in the need for revision surgery. The management of these bony defects can be surgically challenging, and full revisions of well-fixed total knee components can lead to substantial bone loss. We present the case of a 71 year old man who developed knee pain and osteolysis around an uncemented total knee replacement. Due to significant medical comorbidies he was treated by percutaneous cyst granuloma debridement and grafting using an injectable calcium phosphate bone substitute. There were no wound complications, and the patient was allowed to fully weight-bear post-operatively. Histopathology and microbiology of the cyst material confirmed polyethylene granulomata without any evidence of infection. At 6 weeks post-operatively the patient's previous knee pain had resolved, he was able to comfortably fully weight-bear. Preoperative scores (Knee Society Score (KSS) 41, WOMAC score 46.2, and Oxford Knee Score 39) had all improved at the 12-month post-operative review KSS 76, WOMAC 81.7 and Oxford Knee score 21). This is a safe and effective technique with minimal morbidity and may be an appropriate treatment modality when more extensive revision surgery is not possible. The case is discussed with reference to the literature

    An observational study of the austral spring statosphere : dynamics, ozone transport, and the "ozone dilution effect"

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    Thesis (Sc. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1993.Includes bibliographical references (p. 367-385).by Roger John Atkinson.Sc.D

    Space|Time|Place : enabling participation in design research for higher education staff

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    This paper explores the value of design research to better inform design pedagogy in Higher Education. It describes a programme of initiatives aimed at giving staff involved in delivering undergraduate and postgraduate design courses the space, time and place to fully engage with practice-based design research and describes the results of that research. These initiatives aimed to address a perennial problem in design education in the UK. Although being actively involved in research is recognized at the highest levels as beneficial to better staff morale and resulting in better informed teaching, the daily pressures of working in Higher Education combine to restrict the very people who wish to engage with research from doing so. To retain the initial momentum Space/Time/Place provided, the staff established a Community of Practice (COP) ((Lave and Wenger)). The goal of a COP is to bring the peripheral members of the community into full participation within the community guided by more experienced peers who form the core group of the COP. The Space/Time/Place COP met to develop the initial discussions into bids to secure funding for further practice based research. The Community of Practice meetings were supplemented by the use of social media platforms. The strength of support the Space/Time/Place event and Community of Practice have engendered in the staff is undeniable. The outcomes of Space/Time/Place will be exhibited in a group exhibition and used by the authors to model and broker the impact of this approach to other lecturers across the department, faculty and University
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