Papers by Jean Pierre Boon
Pattern Formation and Lattice gas Automata, 1995
ABSTRACT
Pattern Formation and Lattice gas Automata, 1995
... Other models are based on a singular perturbation analysis and are only valid in a certain li... more ... Other models are based on a singular perturbation analysis and are only valid in a certain limit (Weimar, Tyson and Watson [1992a, 1992b]). ... Page 254. 240 Jorg R. Weimar and Jean-Pierre Boon which also achieve quantitative correctness. ...
Advances in Chemical Physics, 2007
Generalized hydrodynamics suggests that at high frequencies, there should be significant departir... more Generalized hydrodynamics suggests that at high frequencies, there should be significant departire from classical hydrodynamics behavior in simple fluids. In particular, the frequency dependence of transport coefficients is not negligible and should introduced observable effects into the propagation of hyper-sound. This work which analyzes rayleigh-Brillouin spectra measured in liquid Argon and Neon reports one of the first experimental investigations of generalized hydrodynamic behavior in simple liquids
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Cette thèse de doctorat a été numérisée par l'Université libre de Bruxelles. L'auteur qui s'oppos... more Cette thèse de doctorat a été numérisée par l'Université libre de Bruxelles. L'auteur qui s'opposerait à sa mise en ligne dans DI-fusion est invité à prendre contact avec l'Université
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We present an analysis of diffusion in terms of the spontaneous density fluctuations in a nonther... more We present an analysis of diffusion in terms of the spontaneous density fluctuations in a nonthermal two-species fluid modeled by a lattice gas automaton. The power spectrum of the density correlation function is computed with statistical mechanical methods, analytically in the hydrodynamic limit, and numerically from a Boltzmann expression for shorter time and space scales. In particular we define an observable – the weighted difference of the species densities – whose fluctuation correlations yield the diffusive mode independently of the other modes so that the corresponding power spectrum provides a measure of diffusion dynamics solely. Automaton simulations are performed to obtain measurements of the spectral density over the complete range of wavelengths (from the microscopic scale to the macroscopic scale of the automaton universe). Comparison of the theoretical results with the numerical experiments data yields the following results: (i) the spectral functions of the lattice ...
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Journal de Physique, 1979
2014 Nous avons appliqué la spectroscopie par corrélation de photons à l'étude de la mobilité des... more 2014 Nous avons appliqué la spectroscopie par corrélation de photons à l'étude de la mobilité des spermatozoides d'échinodermes (Astérias) et nous avons développé une méthode d'analyse des spectres qui permet de déterminer aisément les facteurs caractéristiques du mouvement.
Il Nuovo Cimento C, 1985
(ric e vuto il 12 Fe bbraio 1985) Summary.-• In climat e dynamios tie e fi e ot of int e rnally g... more (ric e vuto il 12 Fe bbraio 1985) Summary.-• In climat e dynamios tie e fi e ot of int e rnally g e n e rat e d fluctuations is usually doscribe d by augm e nting tbe balance équations through tbe addition of r andom fo r ces. In this paper tbe properties of tbe se force s are inve stigate d. A fluctuation-dissipation theo r em r e lating tb e ir covariano e matrix to tbe phe nome nological coe fficie nts sucb as e ddy diffusivity is propose d. Tb e tbe orom is subse que ntly use d to ide ntify tbe statistioal prope rtie s of tbe climatic variable s tbe mse lve s, and tbus to cbaraot e riz e climatic variability from the standpoint of the statistioal tb e ory of irréve rsible prooe sse s. Applications to a simple the rmal conv e ction probl e m and to a zonally av e rag e d e ne rgy-balanco mode l ar e pr e s e nt e d; tbe possibility of e xpérime ntal vérification is discusse d.
1 Hidrodinamika Molecular Hydrodynamics Jean Pierre Boon Sidney Yip, 1980
Journal de Physique, 1978
2014 Nous présentons une étude expérimentale du comportement asymptotique temporel du mouvement b... more 2014 Nous présentons une étude expérimentale du comportement asymptotique temporel du mouvement brownien, basée sur l'analyse des propriétés des fonctions d'autocorrélation de photocomptage obtenues en lumière diffusée par une suspension de particules sphériques. L'analyse statistique des résultats expérimentaux tient compte de l'effet dit des longues queues qui traduit le comportement aux temps longs de la fonction d'autocorrélation des vitesses. La précision statistique atteinte permet de mettre en évidenée une contribution non exponentielle dans la décroissance temporelle de la fonction d'autocorrélation des vitesses, compatible avec l'existence d'un terme en t-3/2. Abstract. 2014 We present an experimental investigation of the asymptotic time behaviour of a Brownian system. Our study is based on the properties of the photoncount correlation functions obtained by light scattering from spherical Brownian particles. The statistical analysis of the data is performed by taking into account the effect of the t-3/2 long time tail. The statistical accuracy reached in the data analysis supports the conclusion that the experimental results are consistent with the existence of a t-3/2 term in the velocity autocorrelation function.
Springer proceedings in physics, 1989
We propose a cellular automaton model for a simple reactiondiffusion system: a three-molecular au... more We propose a cellular automaton model for a simple reactiondiffusion system: a three-molecular autocatalytic scheme known as the Schlagl model. Cellular automata simulations show qualitative behavior in agreement with Schagl's phenomenological description: bistability and front propagation. Quantitatively, significant discrepancies are observed between the phenomenological predictions and the results of the simulations, which can be interpreted in terms of reactive recorrelations. These discrepancies are directly related to the ratio of reactive collisions versus elastic collisions and can be eliminated by efficient "stirring". Correspondingly we observe mesoscopic effects like the formation of unsteady domains which cannot be predicted by the phenomenological theory.
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Papers by Jean Pierre Boon