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F Jiménez-Morales

Publications and source records attributed to F Jiménez-Morales.

6 recordsLinked to original sources
PubMed2006

Stabilization from chaotic to periodical states in a model of cellular automaton for oxidation of CO.

The chaotic behavior of a chemical reaction can be controlled perturbing periodically some of the parameters externally governing the reaction. Based on the resonance phenomenon, the method of external forcing can convert chaotic behavior into a periodical one through the application of a sinusoidal modulation. In this paper we analyze the effect of a periodical perturbation on room temperature in a model of cellular automaton that studies catalytic oxidation of CO. This model considers the reaction of carbon monoxide and oxygen adsorbed on a surface allowing the variation of the surface temperature and analyzing the time oscillations in the reaction. The results of simulations of this model show quasiperiodical and chaotic behaviors. Then the strategy of control through periodical forcing is able to remove the chaotic dynamics by means of the stabilization of periodical solutions, there being enough of a perturbing harmonic function with only one frequency to transform a chaotic state of the system into a periodical state with periodicity 1.

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PubMed2006

Periodical forcing for the control of chaos in a chemical reaction.

Control of the chaotic behavior of a chemical system can be achieved perturbing periodically some control parameters of the system. This procedure based on external forcing, which is based on the phenomenon of resonance, can change a chaotic behavior into a periodical one by means of the application of a sinusoidal perturbation. In this paper, the influence of a periodical modulation added to the parameter controlling the oxygen adsorption rate in a cellular automaton (CA) model studying CO oxidation is analyzed. This CA model considers the oxidation reaction of CO on a catalytic surface, taking into account the catalyst temperature variation in order to analyze the reaction time oscillatory behavior. Simulations of the CA model exhibit chaotic and quasiperiodical behaviors, and it can be shown that the periodical forcing strategy can suppress the chaotic dynamics by means of the stabilization of periodical solutions.

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PubMed2004

A cellular automaton for the modeling of oscillations in a surface reaction.

The reaction of CO and O over a catalytic surface is studied with a cellular automata (CA) model. We extend the CA model proposed by Mai and von Niessen [Phys. Rev. A 44 R6165 (1991)] taking into account the variation of the temperature of the catalyst with the aim of analyzing the existence of oscillations in this reaction. The rate constants for different processes which govern the reaction are chosen in the Arrhenius form. Quasiperiodic, aperiodic, O-poisoned, and CO-poisoned regimes are observed depending on the temperature relaxation parameter. The results from the CA model presented are in agreement with several oscillatory behaviors which the catalyzed oxidation of CO exhibits.

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PubMed2003

Cellular automaton model for the simulation of laser dynamics.

The classical modeling approach for laser study relies on the differential equations. In this paper, a cellular automaton model is proposed as an alternative for the simulation of population dynamics. Even though the model is simplified it captures the essence of laser phenomenology: (i) there is a threshold pumping rate that depends inversely on the decaying lifetime of the atoms and the photons; and (ii) depending on these lifetimes and on the pumping rate, a constant or an oscillatory behavior can be observed. More complex behaviors such as spiking and pattern formation can also be studied with the cellular automaton model.

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PubMed1999

Evolving three-dimensional cellular automata to perform a quasiperiod-3 collective behavior task.

We present results from experiments in which a genetic algorithm (GA) is used to develop three-dimensional cellular automata (CA) to perform a nontrivial collective behavior task. Under a fitness function that is defined as an averaged area in the iterative map, the GA detects a CA rule with quasiperiod-3 (QP3) collective behavior and another with period-3. For rules with QP3 the time autocorrelation function decays as a power law with an exponent of -1/2, according to the predictions of the Kardar-Parisi-Zhang equation, and a space-time diagram reveals the existence of propagating structures inside the system.

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