13,509 research outputs found

    Some aspects of metallic ion chemistry and dynamics in the mesosphere and thermosphere

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    The relationship between the formation of sporadic layers of metallic ion and the dumping of these ions into the upper mesosphere is discussed in terms of the tidal wind, classical (i.e., windshear) and other more complex, perhaps highly nonlinear layer formation mechanisms, and a possible circulation mechanism for these ions. Optical, incoherent scatter radar, rocket, and satellite derived evidence for various layer formation mechanisms and for the metallic ion circulation system is reviewed. The results of simple one dimensional numerical model calculations of sporadic E and intermediate layer formation are presented along with suggestions for more advanced models of intense or blanketing sporadic E. The flux of metallic ions dumped by the tidal wind system into the mesosphere is estimated and compared with estimates of total particle flux of meteoric origin. Possible effects of the metallic ion flux and of meteoric dust on D region ion chemistry are discussed

    Sterilization Assembly Development Laboratory - Monitoring plan

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    Monitoring plan with test requirements and procedures for sterilization assembly development laborator

    An Axisymmetric Object-Based Search for a Flat Compact Dimension

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    A method is presented to search for a hypertorus symmetry axis by the alignment of distant objects. This offers greater sensitivity than previously proposed object-based methods that rely on accurate true distances. When applied to the catalog of objects with z > 1, we find no evidence for a compact dimension. We deduce a lower limit to the compact dimension size D > 0.9 of the distance to the cosmic horizon. This is consistent with independent constraints from the recent analysis of the WMAP microwave background data.Comment: 12 pages, 10 figures, minor revision, accepted by JCA

    Peculiar Velocity and Deaberration of the Sky

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    Recent studies have found the earth's peculiar velocity to be significant in microwave background based tests for compact cosmic topology, and modifications to these tests have been proposed. Tests of non-gaussianity, weak lensing analysis and new tests using improved CMB data will also be sensitive to peculiar velocity. We propose here to simplify matters by showing how to construct a deaberrated CMB map to which any test requiring a Hubble flow viewpoint can be applied without further complication. In a similar manner deaberration can also be applied to object surveys used for example in topological searches and matter distribution analysis. In particular we have produced a revised list of objects with z > 1.0 using the NASA/IPAC Extragalactic Database.Comment: 8 pages, 1 figure, v4 accepted by Ap

    Nuclear Equation of State and Internal Structure of Magnetars

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    Recently, neutron stars with very strong surface magnetic fields have been suggested as the site for the origin of observed soft gamma repeaters (SGRs). We investigate the influence of a strong magnetic field on the properties and internal structure of such strongly magnetized neutron stars (magnetars). The presence of a sufficiently strong magnetic field changes the ratio of protons to neutrons as well as the neutron appearance density. We also study the pion production and pion condensation in a strong magnetic field. We discuss the pion condensation in the interior of magnetars as a possible source of SGRs.Comment: 5 pages with 3 figures, To appear in the Proceedings of the 5th Huntsville Gamma Ray Burst Symposium, Huntsville, Alabama, USA, Oct. 18-22, 199

    Externalities revisited: the use of an environmental equity account

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    This exploratory paper attempts to restart a debate about the incorporation of environmental externalities into the cost structure of the organisation. A number approaches are considered; regulation together with all that would follow such as audit and policing; pollution permits, which probably can only be used with a sinking lid application; and other charging mechanisms such as making the private sector pay for public sector capital funding. The fourth alternative, the use of an environmental equity account, has not been widely considered in the literature. The paper proposes the use of an environmental equity account (after Boone and Rubenstein, 1997) with the express intent of generating a charge for environmental impact based on the cost of control. That is, the cost of implementing state of the art technology compared to that currently in use within the organisation, is used as a balance which may be either paid as a capital sum or carried as a balance sheet entry upon which dividend payments would have to be made. It is envisaged that both capital sums and dividend payments would go to an agency responsible for environmental remediation activity

    Simultaneous VHF and UHF radar observation of the mesosphere at Arecibo during a solar flare: A check on the gradient-mixing hypothesis

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    The results of a two wavelength (VHF and UHF) mesosphere experiment performed at the Arecibo Observatory on January 5, 1981 are discussed. The 46.8-MHz VHF radar (3.21 m Bragg scale) was operated to provide spectral measurements of signals scattered from refractivity fluctuations due to turbulence. Other physical parameters such as radial velocities, scattered signal power, and Doppler spread due to turbulence can be derived from signal spectra. The 430-MHz UHF radar (0.36 m Bragg scale) was used for D-region electron-density measurements using the incoherent scatter technique with a comparable height resolution. The radars were pointed symmetrically about the vertical with a beam spacing of 5.5 degree in the meridional plane. Occurrence of a type 4 solar flare during the experiment produced enhanced D-region electron-density gradients. This was a unique circumstance that provided the possibility of testing the basic premises of the turbulent gradient-mixing hypothesis
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