8,299 research outputs found

    Electromagnetic Meissner effect launcher

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    An electromagnetic projectile launcher provides acceleration of a superconducting projectile through the diamagnetic repulsion of the superconducting projectile. A superconducting layer is provided aft of the projectile, either directly on the projectile or on a platform upon which the projectile is carried, and a traveling magnetic field is caused to propagate along a magnetic field drive coil in which the projectile is disposed. The resulting diamagnetic repulsion between the superconducting projectile and the traveling magnetic field causes the projectile to be propelled along the coil. In one embodiment, a segmented drive coil is used to generate the traveling magnetic field

    Pricing in War Contracts

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    Piezoelectrostatic generator

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    A piezoelectrostatic generator includes a plurality of elongated piezoelectric elements having first and second ends, with the first ends fixedly mounted in a cylindrical housing and the second extending radially inwardly toward an axis. A shaft movable along the axis is connected to the inner ends of the elements to produce bending forces in piezoelectric strips within the elements. Each element includes a pair of strips mounted in surface contact and in electrical series to produce a potential upon bending. Electrodes spaced from the strips by a solid dielectric material act as capacitor plates to collect the potential charge

    A note on the Markoff condition and central words

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    We define Markoff words as certain factors appearing in bi-infinite words satisfying the Markoff condition. We prove that these words coincide with central words, yielding a new characterization of Christoffel words

    Relic High Frequency Gravitational waves from the Big Bang, and How to Detect Them

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    We show conditions for HFGW detection, employing an entropy concept written up by Jack Ng, and Steinhard's proceedure for reconstructing tensorial representations for relic HFGW from the onset of the big bang. The issue of the reality of gravitons as a measurable physical object which was raised by Rothman in 2006 is indirectly answered via a proceedure obtained from Weinberg's 1972 book on gravitation, and all the methodologies so obtained are referenced with respect to engineering specifications of the Li-Baker HFGW detector. In addition, the document also refers to entanglement entropy, and its possible aid in refining measurement predictions. Finally, commentary about HFGW and relic neutrino physics data sets is included, with regards to inflationary model candidatesComment: 15 pages, 1 table, 1 figure. Covers two AIP conference proceeding entries. Pages 1-9 correspond to one ias-spes Huntsville, Alabama February 2009 conference paper on the formalism of HFGW analysis, and pages 9-13 correspond to Neutrino physics-HFGW data set comparison, in terms of different inflationary potential candidate

    Gravitinos, the Lithium problem, and DM production: Is there a corresponding neutrino physics linkage?

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    Studies are cited indicating that gravitino production acts as a natural upper bound to Li6 and Li7 levels, based on what happens after hadronic decay of relic 1 TeV into 100 GeV gravitinos at 1000 s. after the Big Bang. The produced gravitinos contribute a large fraction of required dark matter density. Whether or not gravitinos can be linked to neutrino production depends on which model of dark matter (DM) is assumed or used. A model presented by the author in 2008 links DM of about 100 GeV -- based on a phenomenological Lagrangian creating different Neutrino masses without SUSY -- with a dark matter candidate of about 100 GeV. This may tie in 100 GeV gravitinos with neutrino physics.Comment: 2 pages, no figures. New article in a sequel of DM applications articles. Conference entry to Rencontres De Moriond, for the Cosmology meeting, February 2009, to be published late 2009 by the Gioi company of Vietna

    Construction Of A Rich Word Containing Given Two Factors

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    A finite word ww with w=n\vert w\vert=n contains at most n+1n+1 distinct palindromic factors. If the bound n+1n+1 is attained, the word ww is called \emph{rich}. Let \Factor(w) be the set of factors of the word ww. It is known that there are pairs of rich words that cannot be factors of a common rich word. However it is an open question how to decide for a given pair of rich words u,vu,v if there is a rich word ww such that \{u,v\}\subseteq \Factor(w). We present a response to this open question:\\ If w1,w2,ww_1, w_2,w are rich words, m=max{w1,w2}m=\max{\{\vert w_1\vert,\vert w_2\vert\}}, and \{w_1,w_2\}\subseteq \Factor(w) then there exists also a rich word wˉ\bar w such that \{w_1,w_2\}\subseteq \Factor(\bar w) and wˉm2k(m)+2\vert \bar w\vert\leq m2^{k(m)+2}, where k(m)=(q+1)m2(4q10m)log2mk(m)=(q+1)m^2(4q^{10}m)^{\log_2{m}} and qq is the size of the alphabet. Hence it is enough to check all rich words of length equal or lower to m2k(m)+2m2^{k(m)+2} in order to decide if there is a rich word containing factors w1,w2w_1,w_2

    On the number of palindromically rich words

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    Rich words (also known as full words ) are a special family of finite and infinite words characterised by containing the maximal number of distinct palindromes. We prove that the number of rich words of length n over a finite alphabet A (consisting of 3 or more letters) grows at least polynomially with the size of A. We also show asymptotic exponential growth for the number of rich words of length 2n over a 2-letter alphabet. Moreover, we discuss possible factor complexity functions of rich words and consider the difficult (open) problem of enumerating the finite rich words over a fixed finite alphabet
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