15,367 research outputs found

    Improved method of producing oxide-dispersion-strengthened alloys

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    Dispersion strengthened alloys having the required properties are produced by a process in which the refractory particles are less than 100 to 500 A thick. These are fine enough to ensure the strength characteristics without appreciable degradation of other characteristics. The alloy consists of a matrix metal and a dispersoid metal

    Dispersion strenghthening of metals Progress report, Sep. 1965 - Feb. 1966

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    Apparatus constructed for controlled oxidation of iron-beryllium alloy powder

    Distances to the high galactic latitude molecular clouds G192-67 and MBM 23-24

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    We report on distance determinations for two high Galactic latitude cloud complexes, G192-67 and MBM 23-24. No distance determination exists in the literature for either cloud. Thirty-four early type stars were observed towards the two clouds, more than half of which have parallaxes measured by the Hipparcos satellite. For the remaining stars we have made spectroscopic distance estimates. The data consist of high resolution echelle spectra centered on the Na I D lines, and were obtained over six nights at the Coude Feed telescope at Kitt Peak National Observatory. Interstellar absorption lines were detected towards some of the stars, enabling estimates of the distances to the clouds of 109 +/- 14 pc for G192-67, and of 139 +/- 33 pc for MBM 23-24. We discuss the relationship of these clouds to other ISM features such as the Local Hot Bubble and the local cavity in neutral hydrogen.Comment: 15 pages, 6 embedded figures, to be published in the ApJ Vol. 516, No.

    Phantom energy traversable wormholes

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    It has been suggested that a possible candidate for the present accelerated expansion of the Universe is ''phantom energy''. The latter possesses an equation of state of the form Ï‰â‰Ąp/ρ<−1\omega\equiv p/\rho<-1, consequently violating the null energy condition. As this is the fundamental ingredient to sustain traversable wormholes, this cosmic fluid presents us with a natural scenario for the existence of these exotic geometries. Due to the fact of the accelerating Universe, macroscopic wormholes could naturally be grown from the submicroscopic constructions that originally pervaded the quantum foam. One could also imagine an advanced civilization mining the cosmic fluid for phantom energy necessary to construct and sustain a traversable wormhole. In this context, we investigate the physical properties and characteristics of traversable wormholes constructed using the equation of state p=ωρp=\omega \rho, with ω<−1\omega<-1. We analyze specific wormhole geometries, considering asymptotically flat spacetimes and imposing an isotropic pressure. We also construct a thin shell around the interior wormhole solution, by imposing the phantom energy equation of state on the surface stresses. Using the ''volume integral quantifier'' we verify that it is theoretically possible to construct these geometries with vanishing amounts of averaged null energy condition violating phantom energy. Specific wormhole dimensions and the traversal velocity and time are also deduced from the traversability conditions for a particular wormhole geometry. These phantom energy traversable wormholes have far-reaching physical and cosmological implications. For instance, an advanced civilization may use these geometries to induce closed timelike curves, consequently violating causality.Comment: 9 pages, Revtex4. V2: Considerable comments and references added, no physics changes, now 10 pages. Accepted for publication in Physical Review

    Research on mechanisms of alloy strengthening. Part 1 - Strengthening through fine particle dispersion. Part 2 - Control of structure and properties by means of rapid quenching of liquid metals /splat cooling/ Semiannual report

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    Alloy strengthening mechanisms - strengthening by fine particle dispersion, and structure and properties control by rapid quenching or splat cooling of liquid metal

    Business valuation in bankruptcy : a nonhauthoritative guide; Consulting services practice aid, 02-1

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    https://egrove.olemiss.edu/aicpa_news/1167/thumbnail.jp

    Robotic resection of recurrent pediatric lipoblastoma

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    This case demonstrates successful resection of a rare, recurrent presacral‐pelvic lipoblastoma in a 19‐year‐old female patient. Because of the anatomical location of the mass and its proximity to vital structures, the robotic approach allowed for both optimal visualization and effective debulking of the mass. Furthermore, with the use of an articulating laparoscopic camera, key visualization of the posterior lateral pelvis was possible. Using a wide breadth of technologies and resources is essential to broadening the surgical armamentarium and achieving resectability in otherwise challenging cases.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/147748/1/ases12493_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/147748/2/ases12493.pd

    Tuck me to sleep in my old \u27Tucky home

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    https://digitalcommons.ithaca.edu/sheetmusic/1140/thumbnail.jp

    The Spectrum of Yang Mills on a Sphere

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    In this note, we determine the representation content of the free, large N, SU(N) Yang Mills theory on a sphere by decomposing its thermal partition function into characters of the irreducible representations of the conformal group SO(4,2). We also discuss the generalization of this procedure to finding the representation content of N=4 Super Yang Mills.Comment: 18 pages v2. references added. typos fixe
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