8 research outputs found

    Observations of vector magnetic fields with a magneto-optic filter

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    We describe the use of the magneto-optic filter (MOF) to observe solar magnetic fields in the potassium line at 7699 Å. The filter has been used in the Big Bear video-magnetograph since 23 October. It gives a high sensitivity and dynamic range for longitudinal magnetic fields and enables us to measure transverse magnetic fields using the sigma component. Examples of the observations are presented

    Observations of vector magnetic fields with a magneto-optic filter

    Get PDF
    We describe the use of the magneto-optic filter (MOF) to observe solar magnetic fields in the potassium line at 7699 Å. The filter has been used in the Big Bear video-magnetograph since 23 October. It gives a high sensitivity and dynamic range for longitudinal magnetic fields and enables us to measure transverse magnetic fields using the sigma component. Examples of the observations are presented

    Joint vector magnetograph observations at BBSO, Huairou Station and Mees Solar Observatory

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    Joint vector magnetograph observations were carried out at Big Bear Solar Observatory (BBSO), Huairou Solar Observing Station (Huairou), and Mees Solar Observatory (MSO) in late September 1989. Comparisons of vector magnetograms obtained at the three stations show a high degree of consistency in the morphology of both longitudinal and transverse fields. Quantitative comparisons show the presence of noise, cross-talk between longitudinal field and transverse field, Faraday rotation and signal saturation effects in the magnetograms. We have tried to establish how the scatter in measurements from different instruments is apportioned between these sources of error

    International Space Station (ISS) Internal Active Thermal Control System (IATCS) New Biocide Selection, Qualification and Implementation

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    The Internal Active Thermal Control System (IATCS) aboard the International Space Station (ISS) is primarily responsible for the removal of heat loads from payload and system racks. The IATCS is a water based system which works in conjunction with the EATCS (External ATCS), an ammonia based system, which are interfaced through a heat exchanger to facilitate heat transfer. On-orbit issues associated with the aqueous coolant chemistry began to occur with unexpected increases in CO2 levels in the cabin. This caused an increase in total inorganic carbon (TIC), a reduction in coolant pH, increased corrosion, and precipitation of nickel phosphate. These chemical changes were also accompanied by the growth of heterotrophic bacteria that increased risk to the system and could potentially impact crew health and safety. Studies were conducted to select a biocide to control microbial growth in the system based on requirements for disinfection at low chemical concentration (effectiveness), solubility and stability, material compatibility, low toxicity to humans, compatibility with vehicle environmental control and life support systems (ECLSS), ease of application, rapid on-orbit measurement, and removal capability. Based on these requirements, ortho-phthalaldehyde (OPA), an aromatic dialdehyde compound, was selected for qualification testing. This paper presents the OPA qualification test results, development of hardware and methodology to safely apply OPA to the system, development of a means to remove OPA, development of a rapid colorimetric test for measurement of OPA, and the OPA on-orbit performance for controlling the growth of microorganisms in the ISS IATCS since November 3, 2007

    Joint vector magnetograph observations at BBSO, Huairou Station and Mees Solar Observatory

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    Joint vector magnetograph observations were carried out at Big Bear Solar Observatory (BBSO), Huairou Solar Observing Station (Huairou), and Mees Solar Observatory (MSO) in late September 1989. Comparisons of vector magnetograms obtained at the three stations show a high degree of consistency in the morphology of both longitudinal and transverse fields. Quantitative comparisons show the presence of noise, cross-talk between longitudinal field and transverse field, Faraday rotation and signal saturation effects in the magnetograms. We have tried to establish how the scatter in measurements from different instruments is apportioned between these sources of error

    Investigation into the High Voltage Shutdown of the Oxygen Generator System in the International Space Station

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    The Oxygen Generation System (OGS) Hydrogen Dome Assembly Orbital Replacement Unit (ORU) serial number 00001 suffered a cell stack high-voltage shutdown on July 5, 2010. The Hydrogen Dome Assembly ORU was removed and replaced with the on-board spare ORU serial number 00002 to maintain OGS operation. The Hydrogen Dome Assembly ORU was returned from ISS on STS-133/ULF-5 in March 2011 with test, teardown and evaluation (TT&E) and failure analysis to follow

    Properties of stellar activity in F stars

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    Typescript.Bibliography: leaves 174-180.Photocopy.Microfilm.xiii, 180 leaves, bound ill. 29 c
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