154,289 research outputs found

    A climate for change

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    This paper reports on the findings of a research project investigating the nature of participation of secondary school students in a collaborative research programme. Four groups of students, aged 14 to 15 years old, from a secondary school in the United Kingdom (UK) participated in the study. The students involved in the programme took the role of researchers investigating their peers’ perceptions of climate change using video to visually record their findings. University researchers worked collaboratively with the school students and a teacher from the school through an approach that empowered the students within the research process. Drawing from the ideas and issues raised from an initial briefing session, each group of students developed a short interview schedule to be used whilst investigating the views of their peers. Although the project was on a small scale, the data gathered from the brainstorming activity, video reports and reflective discussions provided a useful snap shot of how the participating students perceived their experience and the nature of their involvement in the research process. The research approach enabled students to take on the role of investigator when interviewing their peers and to offer a voice for both themselves and their peers. Introduction</p

    Direct observation of voids in the vacancy excess region of ion bombarded silicon

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    The results reported in this letter indicate that the spatial separation of the vacancy and interstitial excesses which result from ion bombardment gives rise to stable voids upon annealing at 850 °C even for implants where the projected ion range is only of the order of a few thousand Ångstrom. Such voids have been observed directly by transmission electron microscopy. Furthermore, in cases where both voids and interstitial-based defects are present at different depths, it is found that Au has a strong preference for decorating void surfaces and hence Au can, indeed, be used as a selective detector of open volume defects in Si.One of the authors ~J.W.-L.! acknowledges the Australian Research Council for financial support

    Quark Condensates: Flavour Dependence

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    We determine the q-bar q condensate for quark masses from zero up to that of the strange quark within a phenomenologically successful modelling of continuum QCD by solving the quark Schwinger-Dyson equation. The existence of multiple solutions to this equation is the key to an accurate and reliable extraction of this condensate using the operator product expansion. We explain why alternative definitions fail to give the physical condensate.Comment: 9 pages, 7 figures, uses appolb.cls, LaTeX. Talk presented by R. Williams at the EURIDICE Final Meeting, August 24-27th, 2006, Kazimierz, Polan

    Surface heat flux determination: An analytical and experimental study using a single embedded thermocouple

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    A numerical method by which data from a single embedded thermocouple can be used to predict the transient thermal environment for both high- and low-conductivity materials is described. The results of an investigation performed to verify the method clearly demonstrate that accurate, transient, surface heating conditions can be obtained from a thermocouple l.016 centimeters from the heating surface in a low-conductivity material. Space shuttle orbiter thermal protection system materials having temperature- and pressure-dependent properties, and typical orbiter entry heating conditions were used to verify the accuracy of the analytical procedure. Analytically generated, as well as experimental, data were used to compare predicted and measured surface temperatures

    An efficiency study on obtaining the minimum weight of a thermal protection system

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    Three minimizing techniques are evaluated to determine the most efficient method for minimizing the weight of a thermal protection system and for reducing computer usage time. The methods used (numerical optimization and nonlinear least squares) for solving the minimum-weight problem involving more than one material and more than one constraint are discussed. In addition, the one material and one constraint problem is discussed
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