1,790 research outputs found
Topological derivation of shape exponents for stretched exponential relaxation
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
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
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
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
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
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An environmental justice assessment of the light rail expansion in Denton County, Texas.
This study analyzes the proposed passenger rail line expansion along US Interstate Highway 35 in Denton County, Texas. A multi-dimensional approach was used to investigate potential environmental justice (EJ) consequences from the expansion of the transportation corridor. This study used empirical and historical evidence to identify and prioritize sites for potential EJ concerns. Citizen participation in the decision making process was also evaluated. The findings of this research suggest that the southeast Denton community has the highest potential for environmental justice concerns. This study concludes by offering suggestions for an effective public participation process. These include the incorporation of a community's local history into an environmental justice assessment, and tailoring the public planning process to the demographics and culture of the residents
Heat capacity at the glass transition
A fundamental problem of glass transition is to explain the jump of heat
capacity at the glass transition temperature 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 is defined
as the temperature at which the liquid stops relaxing at the experimental time
scale, the jump of heat capacity at 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 with the quench rate and the correlation
of heat capacity jump with liquid fragility
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