20,748 research outputs found

    Origins of NASA names

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    Names are selected for NASA spaceflight projects and programs from various sources. Some have their foundations in mythology and astrology or legend and folklore. Some have historic connotations; others are based on a description of their mission, often resulting in an acronym. Included are names of launch vehicles, spacecraft, manned spaceflight programs, sounding rockets, and NASA field installations. This study is limited to names of approved projects through 1974; it does not include names of numerous projects which have been or are being studied or projects that were canceled or postponed before reaching actual flight

    Water system virus detection

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    The performance of a waste water reclamation system is monitored by introducing a non-pathogenic marker virus, bacteriophage F2, into the waste-water prior to treatment and, thereafter, testing the reclaimed water for the presence of the marker virus. A test sample is first concentrated by absorbing any marker virus onto a cellulose acetate filter in the presence of a trivalent cation at low pH and then flushing the filter with a limited quantity of a glycine buffer solution to desorb any marker virus present on the filter. Photo-optical detection of indirect passive immune agglutination by polystyrene beads indicates the performance of the water reclamation system in removing the marker virus. A closed system provides for concentrating any marker virus, initiating and monitoring the passive immune agglutination reaction, and then flushing the system to prepare for another sample

    Water system virus detection

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    A monitoring system developed to test the capability of a water recovery system to reject the passage of viruses into the recovered water is described. A nonpathogenic marker virus, bacteriophage F2, is fed into the process stream before the recovery unit and the reclaimed water is assayed for its presence. Detection of the marker virus consists of two major components, concentration and isolation of the marker virus, and detection of the marker virus. The concentration system involves adsorption of virus to cellulose acetate filters in the presence of trivalent cations and low pH with subsequent desorption of the virus using volumes of high pH buffer. The detection of the virus is performed by a passive immune agglutination test utilizing specially prepared polystyrene particles. An engineering preliminary design was performed as a parallel effort to the laboratory development of the marker virus test system. Engineering schematics and drawings of a fully functional laboratory prototype capable of zero-G operation are presented. The instrument consists of reagent pump/metering system, reagent storage containers, a filter concentrator, an incubation/detector system, and an electronic readout and control system

    A new approach to the inverse problem for current mapping in thin-film superconductors

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    A novel mathematical approach has been developed to complete the inversion of the Biot-Savart law in one- and two-dimensional cases from measurements of the perpendicular component of the magnetic field using the well-developed Magneto-Optical Imaging technique. Our approach, especially in the 2D case, is provided in great detail to allow a straightforward implementation as opposed to those found in the literature. Our new approach also refines our previous results for the 1D case [Johansen et al., Phys. Rev. B 54, 16264 (1996)], and streamlines the method developed by Jooss et al. [Physica C 299, 215 (1998)] deemed as the most accurate if compared to that of Roth et al. [J. Appl. Phys. 65, 361 (1989)]. We also verify and streamline the iterative technique, which was developed following Laviano et al. [Supercond. Sci. Technol. 16, 71 (2002)] to account for in-plane magnetic fields caused by the bending of the applied magnetic field due to the demagnetising effect. After testing on magneto-optical images of a high quality YBa2Cu3O7 superconducting thin film, we show that the procedure employed is effective

    Information requirements for supersonic transport operation Final report

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    Effects of meteorological parameters and instrument errors on vertical flight performance of supersonic transport

    A study of weather-dependent data links for deep space applications

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    Weather-dependent data links for deep space applications, and five potential system

    A human factors approach to analysing military command and control

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    This paper applies the Event Analysis for Systemic Teamwork (EAST) method to an example of military command and control. EAST offers a way to describe system level 'emergent properties' that arise from the complex interactions of system components (human and technical). These are described using an integrated methods approach and modelled using Task, Social and Knowledge networks. The current article is divided into three parts: a brief description of the military command and control context, a brief description of the EAST method, and a more in depth presentation of the analysis outcomes. Numerous findings emerge from the application of the method. These findings are compared with similar analyses undertaken in civilian domains, where Network Enabled Capability (NEC) is already in place. The emergent properties of the military scenario relate to the degree of system reconfigurability, systems level Situational Awareness (SA), team-working and the role of mediating technology. It is argued that the EAST method can be used to offer several interesting perspectives on designing and specifying NEC capability in military context

    The importance of tau leptons for supersymmetry searches at the Tevatron

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    Supersymmetry is perhaps most effectively probed at the Tevatron through production and decay of weak gauginos. Most of the analyses of weak gaugino observables require electrons or muons in the final state. However, it is possible that the gauginos will decay primarily to tau leptons, thus complicating the search for supersymmetry. The motivating reasons for high tau multiplicity final states are discussed in three approaches to supersymmetry model building: minimal supergravity, gauge mediated supersymmetry breaking, and more minimal supersymmetry. The concept of ``e/mu/tau candidate'' is introduced, and an observable with three e/mu/tau candidates is defined in analog to the trilepton observable. The maximum mass reach for supersymmetry is then estimated when gaugino decays to tau leptons have full branching fraction.Comment: 9 pages, latex, 2 figures. Presented at the D0 New Phenomena Workshop, UC Davis, 26-28 March 199

    THE EFFECT OF WIND DIRECTION ON FLOW PAST SOUTH GEORGIA

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    A series of simulations of idealized flows past South Georgia are conducted in order to investigate how the wind direction affects the airflow around a real mesoscale mountain. Our experiments build on the work of Petersen et al. (2003) who investigated the impact of upstream wind direction on flow around an idealized mountain designed to be a similar size to Greenland. However, our experiments differ from Petersen’s experiments in two key ways. Firstly, we use real, complex multi-scale orography rather than idealized, smooth orography. Secondly, our mountain is much smaller. Results indicate that the flow features are sensitive to the wind direction, with the flow most effectively blocked when the incident flow at a slight angle to the major axis of the orography. In contrast to Petersen’s experiments around symmetrical idealized orography the flow features are also sensitive to a 180° rotation of the orography. However, the magnitude of the surface pressure force is relatively insensitive to this, varying by less than 10% when the orography is rotated by 180° from any initial orientation
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