1,790 research outputs found

    Topological derivation of shape exponents for stretched exponential relaxation

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    In homogeneous glasses, values of the important dimensionless stretched-exponential shape parameter beta are shown to be determined by magic (not adjusted) simple fractions derived from fractal configuration spaces of effective dimension d* by applying different topological axioms (rules) in the presence (absence) of a forcing electric field. The rules are based on a new central principle for defining glassy states: equal a priori distributions of fractal residual configurational entropy. Our approach and its beta estimates are fully supported by the results of relaxation measurements involving many different glassy materials and probe methods. The present unique topological predictions for beta typically agree with observed values to ~ 1% and indicate that for field-forced conditions beta should be constant for appreciable ranges of such exogenous variables as temperature and ionic concentration, as indeed observed using appropriate data analysis. The present approach can also be inverted and used to test sample homogeneity and quality.Comment: Original 13 pages lengthened to 21 pages (longer introduction, added references and discussion of new experimental data published since original submission

    Scattering amplitudes, black holes and leading singularities in cubic theories of gravity

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    We compute the semi-classical potential arising from a generic theory of cubic gravity, a higher derivative theory of spin-2 particles, in the framework of modern amplitude techniques. We show that there are several interesting aspects of the potential, including some non-dispersive terms that lead to black hole solutions (including quantum corrections) that agree with those derived in Einsteinian cubic gravity (ECG). We show that these non-dispersive terms could be obtained from theories that include the Gauss- Bonnet cubic invariant G3. In addition, we derive the one-loop scattering amplitudes using both unitarity cuts and via the leading singularity, showing that the classical effects of higher derivative gravity can be easily obtained directly from the leading singularity with far less computational cost

    Determination of solid mass fraction in partially frozen hydrocarbon fuels

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    Filtration procedures alone are insufficient to determine the amounts of crystalline solid in a partially frozen hydrocarbon distillate fraction. This is due to the nature of the solidification process by which a large amount of liquid becomes entrapped within an interconnected crystalline structure. A technique has been developed to supplement filtration methods with an independent determination of the amount of liquid in the precipitate thereby revealing the actual value of mass percent crystalline solid, %S. A non-crystallizing dye is injected into the fuel and used as a tracer during the filtration. The relative concentrations of the dye in the filtrate and precipitate fractions is subsequently detected by a spectrophotometric comparison. The filtration apparatus was assembled so that the temperature of the sample is recorded immediately above the filter. Also, a second method of calculation has been established which allows significant reduction in test time while retaining acceptable accuracy of results. Data have been obtained for eight different kerosene range hydrocarbon fuels

    JPART Virtual Issue on Citizen-State Interactions in Public Administration Research

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    This is the author accepted manuscript. The final version is available from Oxford University Press via the DOi in this recordIn this virtual issue, we bring together a collection of research articles that-although not usually grouped together-all illustrate the importance of citizen-state interactions. Specifically, we include articles that directly incorporate citizens' perceptions, attitudes, experiences of, or behavior related to public administration. About 10% of all JPART articles over the life of the journal so far (1991-2015) met our inclusion criteria. Of those articles, we selected seven for this virtual issue on the basis that they have offered important insights into citizen-state interaction at different stages of the policy cycle. We argue that public administration scholarship should focus much more on the role of citizens and citizen-state interactions at all stages of the policy cycle. This research should focus both on the different forms of interaction citizens have with administrators, and the outcomes of these interactions, for bureaucracy and for citizens themselves

    Temperature in nonequilibrium systems with conserved energy

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    We study a class of nonequilibrium lattice models which describe local redistributions of a globally conserved energy. A particular subclass can be solved analytically, allowing to define a temperature T_{th} along the same lines as in the equilibrium microcanonical ensemble. The fluctuation-dissipation relation is explicitely found to be linear, but its slope differs from the inverse temperature T_{th}^{-1}. A numerical renormalization group procedure suggests that, at a coarse-grained level, all models behave similarly, leading to a two-parameter description of their macroscopic properties.Comment: 4 pages, 1 figure, final versio

    Testimony of Chief Executive Officer and President for the Bank of America, Brian T. Moynihan, Testimony Before the FCIC 1-13-2010

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    Heat capacity at the glass transition

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    A fundamental problem of glass transition is to explain the jump of heat capacity at the glass transition temperature TgT_g without asserting the existence of a distinct solid glass phase. This problem is also common to other disordered systems, including spin glasses. We propose that if TgT_g is defined as the temperature at which the liquid stops relaxing at the experimental time scale, the jump of heat capacity at TgT_g follows as a necessary consequence due to the change of system's elastic, vibrational and thermal properties. In this picture, we discuss time-dependent effects of glass transition, and identify three distinct regimes of relaxation. Our approach explains widely observed logarithmic increase of TgT_g with the quench rate and the correlation of heat capacity jump with liquid fragility
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