42 research outputs found

    The James Webb Space Telescope Mission

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    Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least 4m4m. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the 6.5m6.5m James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 years, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space Telescope Overview, 29 pages, 4 figure

    Satellite analysis of the severe 1987 forest fires in northern China and southeastern Siberia

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    Abstract. Meteorological conditions, extremely conducive to fire development and spread in the spring of 1987, resulted in forest fires burning over extremely large areas in the boreal forest zone in northeastern China and the southeastern region of Siberia. The great China fire, one of the largest and most destructive forest fires in recent history, occurred during this period in the Heilongjiang Province of China. Satellite imagery is used to examine the development and areal distribution of 1987 forest fires in this region. Overall trace gas emissions to the atmosphere from these fires are determined using a satellite-derived estimate of area burned in combination with fuel consumption figures and carbon emission ratios for boreal forest fires

    Empowerment of Whom and for What? Financial Literacy Education and the New Regulation of Consumer Financial Services

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    Financial regulators in many states recently have obtained statuory mandates to enhance consumer financial literacy. This paper investicages the development of policy pursuant to such mandates in the UK and Canada to identify how national regulators in both countries represent financial market place. It finds that regulators in both countries represent financial education as empowerment and responsible consumer behaviour. The paper rekates the tension between empowerment and responsibilization aspects of literacy enhancement to policy goals of expectations of protection. It raises questions about regulators' use of consumer education to responsiblize consumption of financial products and calls for further research on the international growth of financial literacy education as a regulatory project

    Surface resistivity and mechanical properties of rotationally molded polyethylene/graphite composites

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    Antistatic polymers are required to dissipate static charges safely from component surfaces. Our overall objective has been to develop cost-effective flame-retarded and antistatic polyethylene compounds suitable for rotomolding. This communication considers the surface resistivity and mechanical properties of rotationally molded linear low-density polyethylene (LLDPE)/graphite composites containing natural Zimbabwean graphite, expandable graphite, or expanded graphite. Dry blending and melt compounding were employed to obtain antistatic composites at the lowest graphite contents. Dry blending was found to be an effective mixing method for rotomolding antistatic LLDPE/graphite composites, thereby eliminating an expensive compounding step. Dry-blended Zimbabwean graphite composites showed the lowest surface resistivity at all graphite contents, with a surface resistivity of 105 Ω/square at 10 wt% loading. Although rotomolded powders obtained following the melt compounding of Zimbabwean graphite exhibited higher resistivity values, the variability was much lower. Injection molding resulted in surface resistivity values above 1014 Ω/square for all compositions used. The rotomolded composites exhibited poor mechanical properties, in contrast to injection-molded composites. The Halpin-Tsai model showed good fits to the tensile modulus data for injection-molded Zimbabwean and expandable graphite.Institutional Research Development Programme (IRDP) of the National Research Foundation of South Africa and Xyris Technology CC.http://onlinelibrary.wiley.com/journal/10.1002/(ISSN)1548-0585hb201
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