946 research outputs found

    Upper Atmosphere Data Program (UADP)

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    Rapid, effective access to the increasing volume of information on stratospheric trace gases, both from measurements and model calculations, is important in advancing our knowledge of the Earth's atmosphere. The data have their origins in a variety of sources, ranging from satellite experiments and 2-D model predictions to individual balloon measurements, and are found in a variety of locations and formats. This task focuses on development and operation of an electronic data base for such trace gas data. The objectives are to provide effective access to these diverse data sets; to foster electronic data access, manipulation, and display; and to support periodic assessment and intercomparison activities

    Applications of tunable high energy/pressure pulsed lasers to atmospheric transmission and remote sensing

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    Atmospheric transmission of high energy C12 O2(16) lasers were improved by pulsed high pressure operation which, due to pressure broadening of laser lines, permits tuning the laser 'off' atmospheric C12 O2(16) absorption lines. Pronounced improvement is shown for horizontal transmission at altitudes above several kilometers, and for vertical transmission through the entire atmosphere. The atmospheric transmission of tuned C12 O2(16) lasers compares favorably with C12 O2(18) isotope lasers and CO lasers. The advantages of tunable, high energy, high pressure pulsed lasers over tunable diode lasers and waveguide lasers, in combining high energies with a large tuning range, are evaluated for certain applications to remote sensing of atmospheric constituents and pollutants. Pulsed operation considerably increases the signal to noise ratio without seriously affecting the high spectral resolution of signal detection obtained with laser heterodyning

    Electron Spectroscopy for Chemical Analysis (ESCA) study of atmospheric particles

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    The results of analyses by ESCA (Electron Spectroscopy for Chemical Analysis) on several Nuclepore filters which were exposed during air pollution studies are presented along with correlative measurements by Neutron Activation Analysis and Scanning Electron Microscopy. Samples were exposed during air pollution studies at Norfolk, Virginia and the NASA Kennedy Space Center (KSC). It was demonstrated that with the ESCA technique it was possible to identify the chemical (bonding) state of elements contained in the atmospheric particulate matter collected on Nuclepore filters. Sulfur, nitrogen, mercury, chlorine, alkali, and alkaline earth metal species were identified in the Norfolk samples. ESCA binding energy data for aluminum indicated that three chemically different types of aluminum are present in the launch and background samples from NASA-KSC

    Study of instabilities in linear Hall current accelerators

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    Ion and electron conservation equations used in analysis of instability of linear Hall current accelerato

    Nonequilibrium plasma boundary layer over a cathode

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    Nonequilibrium plasma boundary layer over cathode in presence of magnetic fiel

    Impacting African American Student Achievement in the Middle School STEM Classroom by Teaching Mathematics Through Arts Integration and Design Thinking

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    Middle school is a transitional period in which many students experience content-specific teachers, travel between classrooms, and explore extracurricular activity options for the first time. Historically, African American middle school students have not fared well in Science, Technology, Engineering, and Mathematics (STEM) on standardized assessments, performing significantly below their Caucasian counterparts in mathematics and science. From the beginning of their academic careers, a lack of access to quality teachers, excessive use of direct instruction strategies, and a lack of resources in their school communities, contribute to their overall apathy towards the subject matter and factor into their underperformance. As a result, fewer African Americans pursue STEM studies in secondary education resulting in underrepresentation in STEM-related professions. To stimulate African American students’ interest in the field, the approach to STEM instruction requires alternative strategies. Some students who do not effectively demonstrate and communicate their understanding of mathematics or science principles using traditional equations instead show a clearer expression of knowledge through alternative, more artistic media. The extent of the effectiveness in implementing a design thinking and arts integrated project-based learning activity (DAIP) to increase African American students’ interest and achievement in STEM subjects was explored

    Analysis of MPD arcs with nonequilibrium ionization

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    One dimensional analysis of magnetoplasm dynamic arcs with nonequilibrium ionizatio
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