5,718 research outputs found
Efficient harmonic oscillator chain energy harvester driven by colored noise
We study the performance of an electromechanical harmonic oscillator chain as
an energy harvester to extract power from finite-bandwidth ambient random
vibrations, which are modelled by colored noise. The proposed device is
numerically simulated and its performance assessed by means of the net
electrical power generated and its efficiency in converting the external
noise-supplied power into electrical power. Our main result is a much enhanced
performance, both in the net electrical power delivered and in efficiency, of
the harmonic chain with respect to the popular single oscillator resonator. Our
numerical findings are explained by means of an analytical approximation, in
excellent agreement with numerics
Diverging fluctuations of the Lyapunov exponents
D. P. acknowledges support by MINECO (Spain) under a Ramón y Cajal fellowship. We acknowledge support by MINECO (Spain) under Project No. FIS2014-59462-P.Peer reviewedPublisher PD
Nonequilibrium Phase Transitions in Directed Small-World Networks
Many social, biological, and economic systems can be approached by complex
networks of interacting units. The behaviour of several models on small-world
networks has recently been studied. These models are expected to capture the
essential features of the complex processes taking place on real networks like
disease spreading, formation of public opinion, distribution of wealth, etc. In
many of these systems relations are directed, in the sense that links only act
in one direction (outwards or inwards). We investigate the effect of directed
links on the behaviour of a simple spin-like model evolving on a small-world
network. We show that directed networks may lead to a highly nontrivial phase
diagram including first and second-order phase transitions out of equilibrium.Comment: 4 pages, RevTeX format, 4 postscript figs, uses eps
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