14,198 research outputs found

    The diffuse X-ray spectrum from 14-200 keV as measured on OSO-5

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    The measurement of energy spectrum of the diffuse component of cosmic X-ray flux made on the OSO-5 spacecraft is described. The contributions to the total counting rate of the actively shielded X-ray detector are considered in some detail and the techniques used to eliminate the non-cosmic components are described. Positive values for the cosmic flux are obtained in seven energy channels between 14 and 200 keV and two upper limits are obtained between 200 and 254 keV. The results can be fitted by a power law spectrum. A critical comparison is made with the OSO-3 results. Conclusions show that the reported break in the energy spectrum at 40 keV is probably produced by an erroneous correction for the radioactivity induced in the detector on each passage through the intense charged particle fluxes in the South Atlantic anomaly

    Modular converter system for low-cost off-grid energy storage using second life Li-ion batteries

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    Lithium ion batteries are promising for small off- grid energy storage applications in developing countries because of their high energy density and long life. However, costs are prohibitive. Instead, we consider 'used' Li-ion batteries for this application, finding experimentally that many discarded laptop cells, for example, still have good capacity and cycle life. In order to make safe and optimal use of such cells, we present a modular power management system using a separate power converter for every cell. This novel approach allows individual batteries to be used to their full capacity. The power converters operate in voltage droop control mode to provide easy charge balancing and implement a battery management system to estimate the capacity of each cell, as we demonstrate experimentally.Comment: Presented at IEEE GHTC Oct 10-14, 2014, Silicon Valle

    Temporal and spectral characteristics of solar flare hard X-ray emission

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    Solar Maximum Mission observations of three flares that impose stringent constraints on physical models of the hard X-ray production during the impulsive phase are presented. Hard X-ray imaging observations of the flares on 1980 November 5 at 22:33 UT show two patches in the 16 to 30 keV images that are separated by 70,000 km and that brighten simultaneously to within 5 s. Observations to O V from one of the footprints show simultaneity of the brightening in this transition zone line and in the total hard X-ray flux to within a second or two. These results suggest but do not require the existence of electron beams in this flare. The rapid fluctuations of the hard X-ray flux within some flares on the time scales of 1 s also provide evidence for electron beams and limits on the time scale of the energy release mechanism. Observations of a flare on 1980 June 6 at 22:34 UT show variations in the 28 keV X-ray counting rate from one 20 ms interval to the next over a period of 10 s. The hard X-ray spectral variations measured with 128 ms time resolution for one 0.5 s spike during this flare are consistent with the predictions of thick-target non-thermal beam model

    Periodicity of high-order functions in the CNS Final progress report, year ending 30 Jun. 1971

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    Analysis of cerebral slow potentials underlying human attentive processes in central nervous syste

    Weed Control in Corn

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    Guide to weed control in corn addresses cultivation, spraying with 2,4-D, pre-emergence spraying, CDAA and CDAA-T, costs of herbicides, and directed-sprays

    Control and Elimination of Leafy Spurge

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    This publication describes leafy spurge characteristics and identification information. It explains how to reduce stands using combinations of cultivation, cropping, and chemicals including soil sterilants

    Human Osteoclastic Activity: Qualitative Histological Measurement

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    Control and Elimination of Leafy Spurge

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    Guide to control and elimination of leafy spurge addresses methods to reduce stands 75 to 90 percent, prevent spreading, 4-year programs, nonselective herbicides, reducing stand in shelterbelts, and prevent reinfestation

    Control and Elimination of Field Bindweed

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    Guide to the control and elimination of field bindweed addresses reeducation of stands through intensive cultivation, prevention of spreading, soil and sterilant
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