11,461 research outputs found
Solar applications analysis for energy storage
The role of energy storage as it relates to solar energy systems is considered. Storage technologies to support solar energy applications, the status of storage technologies, requirements and specifications for storage technologies, and the adequacy of the current storage research and development program to meet these requirements are among the factors discussed. Emphasis is placed on identification of where the greatest potential exists for energy storage in support of those solar energy systems which could have a significant impact on the U.S. energy mix
The "Cameo Principle" and the Origin of Scale-Free Graphs in Social Networks
We formulate a simple edge generation rule based on an inverse like mass
action principle for random graphs over a structured vertex set. We show that
under very weak assumptions on the structure generating distribution we obtain
a scale free distribution for the degree. We furthermore introduce and study a
"my friends are your friends" local search principle which makes the clustering
coefficient large.Comment: 17 pages, Late
Heavy-tailed Distributions In Stochastic Dynamical Models
Heavy-tailed distributions are found throughout many naturally occurring
phenomena. We have reviewed the models of stochastic dynamics that lead to
heavy-tailed distributions (and power law distributions, in particular)
including the multiplicative noise models, the models subjected to the
Degree-Mass-Action principle (the generalized preferential attachment
principle), the intermittent behavior occurring in complex physical systems
near a bifurcation point, queuing systems, and the models of Self-organized
criticality. Heavy-tailed distributions appear in them as the emergent
phenomena sensitive for coupling rules essential for the entire dynamics
What can one learn about Self-Organized Criticality from Dynamical Systems theory ?
We develop a dynamical system approach for the Zhang's model of
Self-Organized Criticality, for which the dynamics can be described either in
terms of Iterated Function Systems, or as a piecewise hyperbolic dynamical
system of skew-product type. In this setting we describe the SOC attractor, and
discuss its fractal structure. We show how the Lyapunov exponents, the
Hausdorff dimensions, and the system size are related to the probability
distribution of the avalanche size, via the Ledrappier-Young formula.Comment: 23 pages, 8 figures. to appear in Jour. of Stat. Phy
Are the stratospheric dust particles meteor ablation debris or interplanetary dust?
Natural and laboratory created fusion crusts and debris from artificial meteor samples were used to develop criteria for recognizing meteor ablation debris in a collection of 5 to 50 micron particles from the stratosphere. These laboratory studies indicate that meteor ablation debris from nickel-iron meteoroids produce spherules containing taenite, wuestite, magnetite, and hematite. These same studies also indicate that ablation debris from chondritic meteoroids produce spheres and fragmentary debris. The spheres may be either silicate rich, containing zoned olivine, magnetite, and glass, or sulfide rich, containing iron oxides (e.g., magnetite, wuestite) and iron sulfides (e.g., pyrrhotite, pentlandite). The fragmentary debris may be either fine-grained aggregates of olivine, magnetite, pyroxene, and occasionally pyrrhotite (derived from the meteorite matrix) or individual olivine and pyroxene grains (derived from meteorite inclusions)
Self-Organized Criticality and Thermodynamic formalism
We introduce a dissipative version of the Zhang's model of Self-Organized
Criticality, where a parameter allows to tune the local energy dissipation. We
analyze the main dynamical features of the model and relate in particular the
Lyapunov spectrum with the transport properties in the stationary regime. We
develop a thermodynamic formalism where we define formal Gibbs measure,
partition function and pressure characterizing the avalanche distributions. We
discuss the infinite size limit in this setting. We show in particular that a
Lee-Yang phenomenon occurs in this model, for the only conservative case. This
suggests new connexions to classical critical phenomena.Comment: 35 pages, 15 Figures, submitte
Small World Graphs by the iterated "My Friends are Your Friends'' Principle
We study graphs obtained by successive creation and destruction of edges into
small neighborhoods of the vertices. Starting with a circle graph of large
diameter we obtain small world graphs with logarithmic diameter, high
clustering coefficients and a fat tail distribution for the degree. Only local
edge formation processes are involved and no preferential attachment was used.
Furthermore we found an interesting phase transition with respect to the
initial conditions.Comment: Latex, 12 pages with 10 figure
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