171 research outputs found

    Evaluation of Cellulose Ethers for Conservation

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    Describes the chemical character of cellulose ethers as a general class of polymers and establishes an approximate ranking of the relative stability of each generic chemical subclass

    The oxidizing power of Illinois coal. II. The effects of extended time,

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    "Reprinted from the Journal of the American Chemical Society, 64, 1809-1811, 1942.

    The Atlantic Wall

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    A study of areas of low radio-thermal emissivity on Venus

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    Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1992.Includes bibliographical references (leaves 168-175).by Robert Joseph Wilt.Ph.D

    NASA's Advanced Radioisotope Power Conversion Technology Development Status

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    NASA's Advanced Radioisotope Power Systems (ARPS) project is developing the next generation of radioisotope power conversion technologies that will enable future missions that have requirements that cannot be met by either photovoltaic systems or by current radioisotope power systems (RPSs). Requirements of advanced RPSs include high efficiency and high specific power (watts/kilogram) in order to meet future mission requirements with less radioisotope fuel and lower mass so that these systems can meet requirements for a variety of future space applications, including continual operation surface missions, outer-planetary missions, and solar probe. These advances would enable a factor of 2 to 4 decrease in the amount of fuel required to generate electrical power. Advanced RPS development goals also include long-life, reliability, and scalability. This paper provides an update on the contractual efforts under the Radioisotope Power Conversion Technology (RPCT) NASA Research Announcement (NRA) for research and development of Stirling, thermoelectric, and thermophotovoltaic power conversion technologies. The paper summarizes the current RPCT NRA efforts with a brief description of the effort, a status and/or summary of the contractor's key accomplishments, a discussion of upcoming plans, and a discussion of relevant system-level benefits and implications. The paper also provides a general discussion of the benefits from the development of these advanced power conversion technologies and the eventual payoffs to future missions (discussing system benefits due to overall improvements in efficiency, specific power, etc.)

    Infectious Mononucleosis: Medical Staff Conference

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    Results from the Advance Power Technology Experiment on the Starshine 3 Satellite

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    The Starshine 3 satellite was put into orbit on September 30, 2001 as part of the Kodiak Star mission. Starshine 3’s primary mission is to measure the atmospheric density of the thermosphere and serve as a learning outreach tool for primary and secondary school age children. Starshine 3 also carries a power technology experiment. Starshine 3 has a small, 1 Watt power system using state-of-the-art components. Eight small clusters of solar cells are distributed across the surface. Each cluster consists of a 6-cell string of 2 cm x 2 cm, GaInP/GaAs/Ge, triple-junction solar cells. These cells have twice the power-to-area ratio as traditional silicon solar cells and 25% more power than GaAs cells. Starshine 3 also carries novel integrated microelectronic power supplies (IMPS). The idea behind an IMPS unit is to allow greater flexibility in circuit design with a power source not tied to a central bus. Each IPS is used to provide 50 microwatts of continuous power throughout the mission. Early results show that this design can be used to provide continuous power under very adverse operating conditions
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