6,770 research outputs found

    Design and analysis considerations for deployment mechanisms in a space environment

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    On the second flight of the INTELSAT V spacecraft the time required for successful deployment of the north solar array was longer than originally predicted. The south solar array deployed as predicted. As a result of the difference in deployment times a series of experiments was conducted to locate the cause of the difference. Deployment rate sensitivity to hinge friction and temperature levels was investigated. A digital computer simulation of the deployment was created to evaluate the effects of parameter changes on deployment. Hinge design was optimized for nominal solar array deployment time for future INTELSAT V satellites. The nominal deployment times of both solar arrays on the third flight of INTELSAT V confirms the validity of the simulation and design optimization

    DEDUCTIVE, INDUCTIVE . . . AND A THIRD WAY

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    Building on two previously published papers, “Failure to Communicate” and “Necessities and Capacities,” (Journal of Modern Ministry, Winter 2011 and Spring 2011) this paper furthers the argument that print-age preaching is not well-suited for the digital age. The paper examines the “third way” options of Calvin Miller and Paul Wilson which seek to combine the best of expository preaching and narrative preaching. This paper does not assert there are no effective “print-age preachers” in pulpits today, nor does it suggest there are no “print-age listeners” in congregations. Rather, the point is that the significant shifts in culture, communication, and technology leave us with the unavoidable conclusion that the “the necessities and capacities of the hearers” have changed, particularly from the mid twentieth-century until the present. This paper identifies deductive preaching as classic, linear, print-age “expository preaching” and discusses the alternatives offered by the “New Homiletic,” particularly the inductive approaches of Fred Craddock and Gene Lowry. The paper concludes the “third way” options of Calvin Miller and Paul Wilson are uniquely helpful in our twenty-first century, North American context

    Reconstructing 3D x-ray CT images of polymer gel dosimeters using the zero-scan method

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    In this study x-ray CT has been used to produce a 3D image of an irradiated PAGAT gel sample, with noise-reduction achieved using the ‘zero-scan’ method. The gel was repeatedly CT scanned and a linear fit to the varying Hounsfield unit of each pixel in the 3D volume was evaluated across the repeated scans, allowing a zero-scan extrapolation of the image to be obtained. To minimise heating of the CT scanner’s x-ray tube, this study used a large slice thickness (1 cm), to provide image slices across the irradiated region of the gel, and a relatively small number of CT scans (63), to extrapolate the zero-scan image. The resulting set of transverse images shows reduced noise compared to images from the initial CT scan of the gel, without being degraded by the additional radiation dose delivered to the gel during the repeated scanning. The full, 3D image of the gel has a low spatial resolution in the longitudinal direction, due to the selected scan parameters. Nonetheless, important features of the dose distribution are apparent in the 3D x-ray CT scan of the gel. The results of this study demonstrate that the zero-scan extrapolation method can be applied to the reconstruction of multiple x-ray CT slices, to provide useful 2D and 3D images of irradiated dosimetry gels

    Investigation and study of a multi-aperture antenna system final report, 1 jan. - 1 apr. 1964

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    Multiple aperture adaptive antenna system for telemetry reception from remote space vehicle

    The Potential of Carbon Storage in the Ocean as Bicarbonate

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    Bicarbonate (HCO3-) and carbonate (CO32-) ions in the ocean are a fundamental component of the global carbon cycle. The oceans contain approximately 38,000 billion tonnes of C as HCO3- and CO32- (40x that in the atmosphere) with fluxes between different parts of this reservoir on the order of \u3c1 GtC per year (Figure 1). Eventually, most of anthropogenic CO2 emitted to the atmosphere will be incorporated into this sink as a consequence of mineral weathering. Intentionally storing additional CO2 as HCO3- in the ocean has been suggested since the mid-90s (e.g., ocean liming, accelerated weathering of limestone, enhanced weathering), but estimates on storage potential, environmental impact, and technical feasibility remain poorly constrained. Our recent work has used the output of recent modelling studies in an attempt to estimate the carbon storage potential of this reservoir, and it is apparent that trillions of tonnes of CO2 can be stored with marginal changes in ocean chemistry when the impact is distributed globally. The changes are more acute around the points of addition, and vary with each technology. All proposals for ocean bicarbonate storage require the extraction, comminution, transport, and dissolution of silicate or carbonate rocks. While the global decadal scale-up of such an operation to impact the climate is not unprecedented, it raises questions regarding environmental and social acceptability. Please click Additional Files below to see the full abstract

    Spectral and total radiation properties of turbulent carbon monoxide/air diffusion flames

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76724/1/AIAA-1986-294-399.pd
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