15,130 research outputs found

    High current lightning test of space shuttle external tank lightning protection system

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    During lift-off, the shuttle launch vehicle (external tank, solid rocket booster and orbiter) may be subjected to a lightning strike. Tests of a proposed lightning protection method for the external tank and development materials which were subjected to simulated lightning strikes are described. Results show that certain of the high resistant paint strips performed remarkably well in diverting the 50 kA lightning strikes

    Computational Fluid Dynamics Applied to Transport Systems in Trees

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    Our ecosystem is dependent upon the ability of photosynthetic plants to convert solar energy into a form of energy useable to biological organisms. Even so, much remains to become understood about how plants function. With such expansive bodies,how do trees cyclewaterand nutrients throughouttheir bodies

    Regular Incidence Complexes, Polytopes, and C-Groups

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    Regular incidence complexes are combinatorial incidence structures generalizing regular convex polytopes, regular complex polytopes, various types of incidence geometries, and many other highly symmetric objects. The special case of abstract regular polytopes has been well-studied. The paper describes the combinatorial structure of a regular incidence complex in terms of a system of distinguished generating subgroups of its automorphism group or a flag-transitive subgroup. Then the groups admitting a flag-transitive action on an incidence complex are characterized as generalized string C-groups. Further, extensions of regular incidence complexes are studied, and certain incidence complexes particularly close to abstract polytopes, called abstract polytope complexes, are investigated.Comment: 24 pages; to appear in "Discrete Geometry and Symmetry", M. Conder, A. Deza, and A. Ivic Weiss (eds), Springe

    Searching for Stars in Compact High-Velocity Clouds. II

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    We address the hypothesis that High Velocity Clouds correspond to the "missing" dwarf galaxies of the Local Group predicted by cosmological simulations. To this end, we present optical and near-infrared photometry of five additional High Velocity Clouds, one of which produces Lyman series absorption on the sight line towards the Quasar Ton S210, with sufficient resolution and sensitivity to enable the detection of an associated stellar content. We do not detect significant stellar populations intrinsic to any of the five clouds. In combination with the results from our paper I, which had yielded non detections of stellar content in another five cases, we find that there is a 50% chance of getting a null result in ten trials if fewer than 7% of all High Velocity Clouds contain stars. We conclude that the population of High Velocity Clouds is an unlikely repository for the "missing" dwarfs of the Local Group.Comment: 6 pages, 3 figures. submitted to MNRA

    Searching for Stars in Compact High-Velocity Clouds. I First Results from VLT and 2MASS

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    We investigate the hypothesis that compact high-velocity clouds (CHVC) are the "missing" dwarf galaxies of the Local Group, by searching them for populations of resolved stars. To this end we conducted two distinct tests based on optical and near-infrared single-star photometry. The optical and the near-infrared experiments complement one another; the optical data help us to rule out distant populations but they are restricted to the central regions of the gas distributions, whereas the near-infrared photometry allows us to set limits on nearby populations spread over the typical cloud size. First, we discuss deep optical single-star photometry of five CHVCs in the V and I filters, obtained with the FORS instrument at the Very Large Telecope (VLT). We find that their optical colour-magnitude diagrams are indistinguishable from that of a population of Galactic stars, and attribute all of the resolved stars to Galactic foreground. We present simulations which address the question of how much of a "normal" dwarf-galaxy type population we might hide in the data. A Kolmogorov-Smirnov test allows us to set very stringent limits on the absence of a resolved stellar population in CHVCs. Second, we also culled near infrared single-star photometry in the J, H, and K_S bands for four of the CHVCs from the Two Micron All Sky Survey (2MASS). The infrared data do not reveal any stellar contents in the CHVCs which resembles that of nearby dwarf galaxies either, and are explained with Galactic foreground as well. We interpret our null detections to indicate that the five CHVCs investigated by us do not host an associated stellar content which is similar to that of the known dwarf galaxies of the Local Group. These CHVCs are very likely pure hydrogen clouds in which no star formation has taken place over cosmic time.Comment: 13 pages, 10 figures, accepted for publication by MNRA

    Review of Women of the New Mexico Frontier 1846-1912

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    Historians of the women\u27s west have centered their analysis around the extent to which Victorian culture shaped women\u27s experience on the frontier. Cheryl Foote\u27s collective biography of white women in New Mexico territory supports the argument that the Victorian cultural values, especially the cult of domesticity, were transferred with few mutations from the East to the Southwest during the nation\u27s westward expansion

    Good Policy or Judicial Abdication: When Courts Uphold Arbitral Awards Which Are in Excess of the Arbitrator\u27s Jurisdiction - Hall v. Superior Court

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    Legislatures and the court system have advanced a strong policy to encourage individuals to arbitrate disputes and avoid the traditional judicial system. 2 In order to promote this policy, it is vital that arbitrators\u27 awards be respected and upheld if at all possible. Consequently, the grounds for review of arbitration awards are limited.\u27 One of the grounds available for vacating an arbitral decision arises when an arbitrator exceeds his or her jurisdiction by purporting to decide issues not submitted by the parties for arbitral determination. 4 This Note discusses the potential consequences to the overall policy goals of encouraging arbitration when reviewing courts fail to vacate arbitration awards which purport to decide issues outside of the arbitrator\u27s jurisdiction
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