219,988 research outputs found

    Summary results of the DOE flywheel development effort

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    The technology and applications evaluation task focuses on defining performance and cost requirements for flywheels in the various areas of application. To date the DOE program has focused on automotive applications. The composite materials effort entails the testing of new commercial composites to determine their engineering properties. The rotor and containment development work uses data from these program elements to design and fabricate flywheels. The flywheels are then tested at the Oak Ridge Flywheel Evaluation Laboratory and their performance is evaluated to indicate possible areas for improvement. Once a rotor has been fully developed it is transferred to the private sector

    The baryon-decuplet in the chiral dynamics of Lambda-hyperons in nuclear matter

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    We study the long range part of the Λ\Lambda-hyperon optical potential in nuclei using Quantum Many Body techniques and flavor-SU(3) Chiral Lagrangians as starting point. More precisely, we study the contributions to the Λ\Lambda-hyperon optical potential due to the long-range two-pion exchange, with Σ\Sigma and Σ∗\Sigma^* baryons in the internal baryonic lines and considering Nh and Δ\Deltah excitations. We also consider the contribution to the spin-orbit potentials that comes out from these terms. Our results support a natural explanation of the smallness of the Λ\Lambda-nuclear spin-orbit interaction and shows the importance of the Σ∗\Sigma^* and Δ\Delta degrees of freedom for the hyperon-nucleus interactions.Comment: 8 pages, 5 figure

    Helical Magnetic Fields from Inflation

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    We analyze the generation of seed magnetic fields during de Sitter inflation considering a non-invariant conformal term in the electromagnetic Lagrangian of the form −14I(ϕ)FμνF~μν-\frac14 I(\phi) F_{\mu \nu} \widetilde{F}^{\mu \nu}, where I(ϕ)I(\phi) is a pseudoscalar function of a non-trivial background field ϕ\phi. In particular, we consider a toy model, that could be realized owing to the coupling between the photon and either a (tachyonic) massive pseudoscalar field and a massless pseudoscalar field non-minimally coupled to gravity, where II follows a simple power-law behavior I(k,η)=g/(−kη)βI(k,\eta) = g/(-k\eta)^{\beta} during inflation, while it is negligibly small subsequently. Here, gg is a positive dimensionless constant, kk the wavenumber, η\eta the conformal time, and β\beta a real positive number. We find that only when β=1\beta = 1 and 0.1≲g≲20.1 \lesssim g \lesssim 2 astrophysically interesting fields can be produced as excitation of the vacuum, and that they are maximally helical.Comment: 17 pages, 1 figure, subsection IIc and references added; accepted for publication in IJMP

    Inexpensive, removable coating for plaster tooling

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    Procedure for thinning and spaying a vinyl material provides strippable film for plaster surfaces. Coating is low-cost, effective seal against moisture and other sources of damage. Coating consists of a mixture of hot-spray vinyl material and 30 to 50 percent by volume of methyl ethyl ketone
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