4,217 research outputs found

    Interim solar cell testing procedures for terrestrial applications

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    An interim draft of a set of test procedures, developed by NASA/ERDA, for the manufacture of solar cells is introduced. This version includes procedures for cell testing both outdoors in natural sunlight and indoors in simulated sunlight, a description of the necessary apparatus and equipment, the calibration and use of standard solar cells, and a proposed air-mass-two (AM2) solar spectrum

    User's guide for the Nimbus 7 ERB Solar Analysis Tape (ESAT)

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    Five years of Nimbus 7 ERB solar data is available in compact form on a single ERB solar analysis tape (ESAT). The period covered is November 16, 1978 through October 31, 1983. The Nimbus 7 satellite performs just under 14 orbits a day and the ERB solar telescope observe the Sun once per orbit as the satellite passes + or - near the south pole. The data were carefully calibrated and screened. Mean orbital and daily values are given for the total solar irradiance plus selected spectral intervals. In addition, selected solar activity indicators are on the tape. The ERB experiment, the solar data calibration and screening procedures, the solar activity indicators, and the tape format are described briefly

    Manual of Criminal Law and Procedure

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    Intended to aid to Alaska law enforcement officers in the performance of their duties in the field, this manual was designed to provide brief, quick access to major points of substantive and procedural criminal law. The manual contained discussion and procedural guidelines for investigatory stops, identification procedures including line-ups, arrest, search and seizure, interrogation, as well as discussion of justification for the use of nondeadly and deadly force whether by peace officers or civilians, culpability, entrapment, trial preparation, and media relations. The section on substantive criminal law deals with a selection of crimes most likely to be encountered by "street" officers as defined with the recently enacted Revised Alaska Criminal Code (effective January 1, 1980), desribing elements of each crime, investigative hints, and differences with previous provisions of the criminal code, where relevant.Alaska Department of Law Grant No. 78-A-014Introduction / Criminal Procedures / Substantive Criminal Law / Justification / Culpability / Entrapment / Trial Preparation / Media Relations / Appendice

    Preliminary results from the advanced photovoltaic experiment flight test

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    The Advanced Photovoltaic Experiment is a space flight test designed to provide reference cell standards for photovoltaic measurement as well as to investigate the solar spectrum and the effect of the space environment on solar cells. After a flight of 69 months in low earth orbit as part of the Long Duration Exposure Facility set of experiments, it was retrieved in January, 1990. The electronic data acquisition system functioned as designed, measuring and recording cell performance data over the first 358 days of flight; limited by battery lifetime. Significant physical changes are also readily apparent, including erosion of front surface paint, micrometeoroid and debris catering and contamination

    Fuel quality/processing study. Volume 4: On site processing studies

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    Fuel treated at the turbine and the turbine exhaust gas processed at the turbine site are studied. Fuel treatments protect the turbine from contaminants or impurities either in the upgrading fuel as produced or picked up by the fuel during normal transportation. Exhaust gas treatments provide for the reduction of NOx and SOx to environmentally acceptable levels. The impact of fuel quality upon turbine maintenance and deterioration is considered. On site costs include not only the fuel treatment costs as such, but also incremental costs incurred by the turbine operator if a turbine fuel of low quality is not acceptably upgraded

    Imaging faint brown dwarf companions close to bright stars with a small, well-corrected telescope aperture

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    We have used our 1.6 m diameter off-axis well-corrected sub-aperture (WCS) on the Palomar Hale telescope in concert with a small inner-working-angle (IWA) phase-mask coronagraph to image the immediate environs of a small number of nearby stars. Test cases included three stars (HD 130948, HD 49197 and HR7672) with known brown dwarf companions at small separations, all of which were detected. We also present the initial detection of a new object close to the nearby young G0V star HD171488. Follow up observations are needed to determine if this object is a bona fide companion, but its flux is consistent with the flux of a young brown dwarf or low mass M star at the same distance as the primary. Interestingly, at small angles our WCS coronagraph demonstrates a limiting detectable contrast comparable to that of extant Lyot coronagraphs on much larger telescopes corrected with current-generation AO systems. This suggests that small apertures corrected to extreme adaptive optics (ExAO) levels can be used to carry out initial surveys for close brown dwarf and stellar companions, leaving followup observations for larger telescopes.Comment: accepted for publication in the Astrophysical Journa

    The Vector Vortex Coronagraph: Laboratory Results and First Light at Palomar Observatory

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    High-contrast coronagraphy will be needed to image and characterize faint extra-solar planetary systems. Coronagraphy is a rapidly evolving field, and many enhanced alternatives to the classical Lyot coronagraph have been proposed in the past ten years. Here, we discuss the operation of the vector vortex coronagraph, which is one of the most efficient possible coronagraphs. We first present recent laboratory results, and then first light observations at the Palomar observatory. Our near-infrared H-band (centered at ~ 1.65 microns) and K-band (centered at ~ 2.2 microns) vector vortex devices demonstrated excellent contrast results in the lab, down to ~ 1e-6 at an angular separation of 3 lb/d. On sky, we detected a brown dwarf companion 3000 times fainter than its host star (HR 7672) in the Ks band (centered at ~2.15 microns), at an angular separation of ~ 2.5 lb/d. Current and next-generation high-contrast instruments can directly benefit from the demonstrated capabilities of such a vector vortex: simplicity, small inner working angle, high optical throughput (>90%), and maximal off-axis discovery space

    BCL-2 Protein Expression is Widespread in the Developing Nervous-System and Retained in the Adult PNS

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    Cell death is a common feature of neural development in all vertebrates. The bcl-2 proto-oncogene has been shown to protect a variety of cell types from programmed cell death. We have examined the distribution of bcl-2 protein in the developing and adult nervous systems. bcl-2 protein is widespread during embryonic development. Proliferating neuroepithelial cells of ventricular zones as well as the postmitotic cells of the cortical plate, cerebellum, hippocampus and spinal cord express bcl-2. Postnatally, bcl-2 is principally retained in the granule cells of the cerebellum and dentate gyrus of the hippocampus. bcl-2 expression in the CNS declines with aging. In the peripheral nervous system, neurons and supporting cells of sympathetic and sensory ganglia retain substantial bcl-2 protein throughout life. The widespread expression of bcl-2 in CNS and PNS neurons during embryonic development and its selective retention in the adult PNS is consistent with a role for bcl-2 in regulating neuronal survival. In addition, the expression of bcl-2 in some neuronal populations beyond the recognized period of cell death is suggestive of a role for bcl-2 beyond simply protecting neurons from developmental cell death
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