4,164 research outputs found

    Quick-disconnect coupling safe transfer of hazardous fluids

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    Quick-disconnect coupling is used for uncoupling of plumbing during ground-to-vehicle transfer of cryogenic and hazardous fluids. The coupling allows remote positive control of liquid pressure and flow during the transfer operation, remote connection and separation capabilities, and negligible liquid spillage upon disconnection

    Accurate, rapid, temperature and liquid-level sensor for cryogenic tanks

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    Thermopiles measure ullage gas temperatures to within plus or minus 1.65 deg K between 20 and 300 deg K, and also serve as point liquid-level sensors. Thermopile technique measures smaller temperature differences by keeping the reference junctions inside the tank and near the temperature range of the measuring junction

    Exotic Statistics for Ordinary Particles in Quantum Gravity

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    Objects exhibiting statistics other than the familiar Bose and Fermi ones are natural in theories with topologically nontrivial objects including geons, strings, and black holes. It is argued here from several viewpoints that the statistics of ordinary particles with which we are already familiar are likely to be modified due to quantum gravity effects. In particular, such modifications are argued to be present in loop quantum gravity and in any theory which represents spacetime in a fundamentally piecewise-linear fashion. The appearance of unusual statistics may be a generic feature (such as the deformed position-momentum uncertainty relations and the appearance of a fundamental length scale) which are to be expected in any theory of quantum gravity, and which could be testable.Comment: Awarded an honourable mention in the 2008 Gravity Research Foundation Essay Competitio

    The Post-Newtonian Limit of f(R)-gravity in the Harmonic Gauge

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    A general analytic procedure is developed for the post-Newtonian limit of f(R)f(R)-gravity with metric approach in the Jordan frame by using the harmonic gauge condition. In a pure perturbative framework and by using the Green function method a general scheme of solutions up to (v/c)4(v/c)^4 order is shown. Considering the Taylor expansion of a generic function ff it is possible to parameterize the solutions by derivatives of ff. At Newtonian order, (v/c)2(v/c)^2, all more important topics about the Gauss and Birkhoff theorem are discussed. The corrections to "standard" gravitational potential (tttt-component of metric tensor) generated by an extended uniform mass ball-like source are calculated up to (v/c)4(v/c)^4 order. The corrections, Yukawa and oscillating-like, are found inside and outside the mass distribution. At last when the limit f→Rf\rightarrow R is considered the f(R)f(R)-gravity converges in General Relativity at level of Lagrangian, field equations and their solutions.Comment: 16 pages, 10 figure

    Fractional Super Lie Algebras and Groups

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    n^{th} root of a Lie algebra and its dual (that is fractional supergroup) based on the permutation group SnS_n invariant forms are formulated in the Hopf algebra formalism. Detailed discussion of S3S_3-graided sl(2)sl(2) algebras is done.Comment: 13 pages, detailed discussion of S3S_3-graided sl(2)sl(2) is adde

    An accurate equation of state for the one component plasma in the low coupling regime

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    An accurate equation of state of the one component plasma is obtained in the low coupling regime 0≤Γ≤10 \leq \Gamma \leq 1. The accuracy results from a smooth combination of the well-known hypernetted chain integral equation, Monte Carlo simulations and asymptotic analytical expressions of the excess internal energy uu. In particular, special attention has been brought to describe and take advantage of finite size effects on Monte Carlo results to get the thermodynamic limit of uu. This combined approach reproduces very accurately the different plasma correlation regimes encountered in this range of values of Γ\Gamma. This paper extends to low Γ\Gamma's an earlier Monte Carlo simulation study devoted to strongly coupled systems for 1≤Γ≤1901 \leq \Gamma \leq 190 ({J.-M. Caillol}, {J. Chem. Phys.} \textbf{111}, 6538 (1999)). Analytical fits of u(Γ)u(\Gamma) in the range 0≤Γ≤10 \leq \Gamma \leq 1 are provided with a precision that we claim to be not smaller than p=10−5p= 10^{-5}. HNC equation and exact asymptotic expressions are shown to give reliable results for u(Γ)u(\Gamma) only in narrow Γ\Gamma intervals, i.e. 0≤Γ≲0.50 \leq \Gamma \lesssim 0.5 and 0≤Γ≲0.30 \leq \Gamma \lesssim 0.3 respectively
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