8,299 research outputs found
Electromagnetic Meissner effect launcher
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
Piezoelectrostatic generator
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
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
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?
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
A finite word with contains at most distinct
palindromic factors. If the bound is attained, the word is called
\emph{rich}. Let \Factor(w) be the set of factors of the word . 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 if there is a rich word such that \{u,v\}\subseteq
\Factor(w). We present a response to this open question:\\ If are
rich words, , and
\{w_1,w_2\}\subseteq \Factor(w) then there exists also a rich word
such that \{w_1,w_2\}\subseteq \Factor(\bar w) and , where and is the size
of the alphabet. Hence it is enough to check all rich words of length equal or
lower to in order to decide if there is a rich word containing
factors
On the number of palindromically rich words
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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