11,282 research outputs found

    Laminated PAINT

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    Though we may not perceive it, we are surrounded by material-in-flux. Inert materials degrade and the events that comprise our natural and social environments causally thread into a duration that unifies us in our incomprehension. Sounds reveal ever-present vibrations of the landscape: expressions of the flexuous ground on which we stand

    High temperature circuit breaker

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    Alternating current circuit breaker is suitable for reliable long-term service at 1000 deg F in the vacuum conditions of outer space. Construction materials are resistant to nuclear radiation and vacuum welding. Service test conditions and results are given

    Asteroseismic modeling of 16 Cyg A & B using the complete Kepler data set

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    Asteroseismology of bright stars with well-determined properties from parallax measurements and interferometry can yield precise stellar ages and meaningful constraints on the composition. We substantiate this claim with an updated asteroseismic analysis of the solar-analog binary system 16 Cyg A & B using the complete 30-month data sets from the Kepler space telescope. An analysis with the Asteroseismic Modeling Portal (AMP), using all of the available constraints to model each star independently, yields the same age (t=7.0±0.3t=7.0 \pm 0.3 Gyr) and composition (Z=0.021±0.002Z=0.021 \pm 0.002, Yi=0.25±0.01Y_i=0.25 \pm 0.01) for both stars, as expected for a binary system. We quantify the accuracy of the derived stellar properties by conducting a similar analysis of a Kepler-like data set for the Sun, and we investigate how the reliability of asteroseismic inference changes when fewer observational constraints are available or when different fitting methods are employed. We find that our estimates of the initial helium mass fraction are probably biased low by 0.02-0.03 from neglecting diffusion and settling of heavy elements, and we identify changes to our fitting method as the likely source of small shifts from our initial results in 2012. We conclude that in the best cases reliable stellar properties can be determined from asteroseismic analysis even without independent constraints on the radius and luminosity.Comment: 5 emulateapj pages, 1 table, 1 figure. ApJ Letters, accepte

    Spinodal Decomposition in High Temperature Gauge Theories

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    After a rapid increase in temperature across the deconfinement temperature Td% T_{d}, pure gauge theories exhibit unstable long wavelength fluctuations in the approach to equilibrium. This phenomenon is analogous to spinodal decomposition observed in condensed matter physics, and also seen in models of disordered chiral condensate formation. At high temperature, the unstable modes occur only in the range 0≤k0\leq k ≤kc\leq k_{c}, where kck_{c} is on the order of the Debye screening mass mDm_D. Equilibration always occurs via spinodal decomposition for SU(2)SU(2) at temperatures T>TdT>T_{d} and for SU(3) for T≫TdT\gg T_{d}. For SU(3) at temperatures T≳TdT\gtrsim T_{d}, nucleation may replace spinodal decomposition as the dominant equilibration mechanism. Monte Carlo simulations of SU(2) lattice gauge theory exhibit the predicted phenomena. The observed value of kck_c is in reasonable agreement with a value predicted from previous lattice measurements of mDm_D.Comment: minor revisions, 16 pages, 6 figures, RevTe
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