14,159 research outputs found

    Radar scatterometer data analysis - Sea state. NASA/MSC Mission 20 and Mission 34

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    Analysis of sea state radar scatterometer data from NASA/MSC missions 20 and 3

    Atmospheric densities from Explorer 17 density gauges and a comparison with satellite drag data

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    Atmospheric density data from Explorer XVII GAUGES and satellite drag dat

    The Harold C. Ernst Collection of Portable Sundials

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    A catalog of sundials from the Harold C. Ernst Collection of Portable Sundials, and a handy reference book on the subject of portable sundials. The sundial is the most ancient scientific instrument to come down to us unchanged. As such it is deserving of a better position in life than that of an ornament. It has played a vital part in the life of man for many thousands of years, and even today it serves us well where the mechanical watch fails. The authors particularly draw attention to the system of classifying, labeling, and cataloging sundials, described in Chapter II. This is the first attempt to bring order out of confusion in sundials

    From Microscales to Macroscales in 3D: Selfconsistent Equation of State for Supernova and Neutron Star Models

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    First results from a fully self-consistent, temperature-dependent equation of state that spans the whole density range of neutron stars and supernova cores are presented. The equation of state (EoS) is calculated using a mean-field Hartree-Fock method in three dimensions (3D). The nuclear interaction is represented by the phenomenological Skyrme model in this work, but the EoS can be obtained in our framework for any suitable form of the nucleon-nucleon effective interaction. The scheme we employ naturally allows effects such as (i) neutron drip, which results in an external neutron gas, (ii) the variety of exotic nuclear shapes expected for extremely neutron heavy nuclei, and (iii) the subsequent dissolution of these nuclei into nuclear matter. In this way, the equation of state is calculated across phase transitions without recourse to interpolation techniques between density regimes described by different physical models. EoS tables are calculated in the wide range of densities, temperature and proton/neutron ratios on the ORNL NCCS XT3, using up to 2000 processors simultaneously.Comment: 6 pages, 11 figures. Published in conference proceedings Journal of Physics: Conference Series 46 (2006) 408. Extended version to be submitted to Phys. Rev.

    Study of ice accretion on icing wind tunnel components

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    In a closed loop icing wind tunnel the icing cloud is simulated by introducing tiny water droplets through an array of nozzles upstream of the test section. This cloud will form ice on all tunnel components (e.g., turning vanes, inlet guide vanes, fan blades, and the heat exchanger) as the cloud flows around the tunnel. These components must have the capacity to handle their icing loads without causing significant tunnel performance degradation during the course of an evening's run. To aid in the design of these components for the proposed Altitude Wind Tunnel (AWT) at NASA Lewis Research Center the existing Icing Research Tunnel (IRT) is used to measure icing characteristics of the IRT's components. The results from the IRT are scaled to the AWT to account for the AWT's larger components and higher velocities. The results show that from 90 to 45 percent of the total spray cloud froze out on the heat exchanger. Furthermore, the first set of turning vanes downstream of the test section, the FOD screen and the fan blades show significant ice formation. The scaling shows that the same results would occur in the AWT

    Development and evaluation of scatterometer data processing algorithms

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    There are no author-identified significant results in this report

    Efficacy of crustal superfluid neutrons in pulsar glitch models

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    In order to assess the ability of purely crust-driven glitch models to match the observed glitch activity in the Vela pulsar, we conduct a systematic analysis of the dependence of the fractional moment of inertia of the inner crustal neutrons on the stiffness of the nuclear symmetry energy at saturation density LL. We take into account both crustal entrainment and the fact that only a fraction YgY_{\rm g} of the core neutrons may couple to the crust on the glitch-rise timescale. We use a set of consistently-generated crust and core compositions and equations-of-state which are fit to results of low-density pure neutron matter calculations. When entrainment is included at the level suggested by recent microscopic calculations and the core is fully coupled to the crust, the model is only able to account for the Vela glitch activity for a 1.4M⊙M_{\odot} star if the equation of state is particularly stiff L>100L>100 MeV. However, an uncertainty of about 10\% in the crust-core transition density and pressure allows for the Vela glitch activity to be marginally accounted for in the range L≈30−60L\approx30-60MeV consistent with a range of experimental results. Alternatively, only a small amount of core neutrons need be involved. If less than 50\% of the core neutrons are coupled to the crust during the glitch, we can also account for the Vela glitch activity using crustal neutrons alone for EOSs consistent with the inferred range of LL. We also explore the possibility of Vela being a high-mass neutron star, and of crustal entrainment being reduced or enhanced relative to its currently predicted values.Comment: 10 pages, 6 figure

    Rangeland biomass estimation demonstration

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    Because of their sensitivity to chlorophyll density, green leaf density, and leaf water density, two hand-held radiometers which have sensor bands coinciding with thematic mapper bands 3, 4, and 5 were used to calibrate green biomass to LANDSAT spectral ratios as a step towards using portable radiometers to speed up ground data acquisition. Two field reflectance panels monitored incoming radiation concurrently with sampling. Software routines were developed and used to extract data from uncorrected tapes of MSS data provided in NASA LANDSAT universal format. A LANDSAT biomass calibration curve estimated the range biomass over a four scene area and displayed this information spatially as a product in a format of use to ranchers. The regional biomass contour map is discussed
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