UB QF

Nonlinear Dynamics Group





Main Researcher:

Dr. Francesc Sagués

Researchers:

Dr. Ramon Reigada
Sergio Alonso
Toni Pons

Research Topics:

Pattern growth far from equilibrium
Theoretical, computationally based and experimental work is devoted to the study of the morphology, growth and response function of fractal and regular patterns grown under non-equilibrium conditions. The prototypical scenario is electrocrystallization of metals.

Diffusion-controlled processes in chemical systems
We study the A+B -> 0 reaction in diffusion-controlled systems, in which segregation of reactants and anomalous kinetic behaviors appear. We also investigate how this behavior is affected by some stirring processes.

Mixing effects on particle dispersion
We study the dispersion of particles under the influence of a synthetic turbulent flow with prescribed statistical properties. We investigate the Richardson Law and the mechanisms (diffusive and ballistic) of dispersion. Study of inertial effects: accumulation of particles. Study of plankton dynamics.

Energy transport and localization at the molecular scale
We study chains (and 2D-arrays) of oscillators with anharmonicity in which we find efficient mechanisms of energy transport and localization. Thermal equilibrium, temperature-enhanced pulse propagation, thermal resonance, coupling to a chemical reaction and stability of breathers.

Fluctuation effects on Chemical Fronts and Waves
We study the external spatial distributed fluctuation effects on spatio-temporal structures formed in chemical systems with nonlinear dynamics and far from equilibrium.

Chemoconvection
We use this word for the hydrodynamical flow induced by an unstable density stratification produced by a chemical reaction within a fluid. We study, theoretically and experimentally, the pattern formation process resulting from this instability.

Formation of nano and microstructures in soft-matter systems
We study the formation of spatio-temporal structures arising at the micro and submicro scales in soft-matter systems. The systems of interest are monolayers and bilayers composed by amphiphilic compounds like fatty acids, phospholipids, etc.


'Grup de Recerca Consolidat de Dinàmica No Lineal'

Useful Links




Scientific Publications

2002
2001
2000
1999
1998
1997
1996
1995
1994

2002


"Energy relaxation in Fermi-Pasta-Ulam arrays"

R. Reigada, A. Sarmiento and K. Lindenberg.
Physica A 305(3-4), 467 (2002)

"Traveling waves and nonequilibrium stationary patterns in two-component reactive Langmuir monolayers"

R. Reigada, F. Sagués and A. S. Mikhailov.
Phys.Rev.Lett. 89(3), 038301 (2002)

"Binary reaction of nonpassively advected particles immersed in turbulent flows"

R. Reigada, F. Sagués and J. M. Sancho.
J. Chem. Phys. 117(1), 258 (2002)

"Asymptotic dynamics of breathers in Fermi-Pasta-Ulam chains"

R. Reigada, A. Sarmiento and K. Lindenberg.
Accepted in the Phys. Rev. E

2001


"Thermal resonance in signal transmission"

R. Reigada, A. Sarmiento and K. Lindenberg.
Phys. Rev. E 63, 066113 (2001)

"Inertial effects on reactive particles advected by turbulence"

R. Reigada, F. Sagués and J. M. Sancho.
Phys. Rev. E 64(4), 026307 (2001)

"Resonant motion of discrete breathers in curved nonlinear chains"

R. Reigada, J. M. Sancho, M. Ibañes and G. P. Tsironis
J. Phys. A 34, 8465 (2001)

"Energy relaxation in nonlinear one-dimensional lattices"

R. Reigada, A. Sarmiento and K. Lindenberg.
Phys. Rev. E 64, 066608 (2001)

" Formation and Distribution of Point-Defects on a Disclination Line Near a Free Nematic Interface"

J. Ignés-Mullol., J. Baudry and P. Oswald
Phys. Rev. E 63(3), 031701 (2001)

" Shear-Induced Molecular Precession in a Hexatic Langmuir Monolayer"

J. Ignés-Mullol and D. K. Schwartz
Nature 410, 348 (2001)

" Molecular-Orientation in Langmuir Monolayers Under Shear"

J. Ignés-Mullol and D. K. Schwartz
Langmuir 17(10), 3017 (2001)

" Microrheology of a Sheared Langmuir Monolayer - Elastic Recovery and Interdomain Slippage"

A. T. Ivanova, J. Ignés-Mullol, et al.
Langmuir 17(11), 3406 (2001)

2000


"Particle dispersion in synthetic turbulent flows"

R. Reigada, A. C. Martí, I. M. Sokolov, F. Sagués and J. M. Sancho.
Phys. Rev. E 62(4), 4997 (2000)

"Pattern Formation in the Methylene-Blue-Glucose System"

A. J. Pons, F. Sagués, M. A. Bees and P. G. Sorensen.
J. Phys. Chem. B 104(10), 2251 (2000)

"Chemoconvection: a chemically driven hydrodynamic instability"

M. A. Bees, A. J. Pons, P. G. Sorensen and F. Sagués.
Accepted in the J. Chem. Phys.

"Brownian motion of spiral waves driven by spatio-temporal structured noise"

I. Sendiña-Nadal, S. Alonso, V. Perez-Muñuzuri, M. Gomez-Gesteira,
V. Perez-Villar, L. Ramirez-Piscina, J. Casademunt, J.M. Sancho and F. Sagués.
Phys. Rev. Lett. 84, 2734 (2000)

"Harvesting thermal fluctuations: Activation process induced by a nonlinear chain in thermal equilibrium"

R. Reigada, A. Sarmiento, A. H. Romero, J. M. Sancho and K. Lindenberg.
J. Chem. Phys. 112(23), 10615 (2000)

"Alignment of Hexatic Langmuir Monolayers Under Shear"

J. Ignés-Mullol and D. K. Schwartz.
Phys. Rev. Lett. 85(7), 1476 (2000)

"Growth and Melting of the Nematic Phase - Sample Thickness Dependence of the Mullins-Sekerka Instability"

J. Ignés-Mullol and P. Oswald.
Phys. Rev. E 61(4), 3969 (2000)

1999


"Evaporation and coarsening dynamics with open boundaries"

A. M. Lacasta, F. Sagués, J. M. Sancho and I. M. Sokolov.
Phys. Rev. E 59, 189 (1999)

"Study of a bimolecular annihilation process for coarsening reactants"

A. M. Lacasta, F. Sagués, I. M. Sokolov and J. M. Sancho.
J. Chem. Phys. 110, 6458 (1999)

"Dimensional crossovers in the A+B->0 reaction in tubular geometries"

R.Reigada and K.Lindenberg.
J. Phys. Chem. A 103, 8041 (1999)

"Arrays of nonlinear oscillators: Energy localization, energy propagation and thermal resonance"

K.Lindenberg, R.Reigada, A.Sarmiento, A.H.Romero and J.M.Sancho.
Stochaos: Stochastic and chaotic dynamics in the lakes, D.S.Broomhead, et.al.
Ed. American Institute of Physics, Woodbury, NY (1999)

"Enhanced pulse propagation in non/linear arrays of oscillators"

R.Reigada, A.H.Romero, A.Sarmiento and K.Lindenberg.
Phys. Rev. E 60, 5317 (1999)

"One-dimensional arrays of oscillators: Energy localization in thermal equilibrium"

R.Reigada, A.H.Romero, A.Sarmiento and K.Lindenberg.
J. Chem. Phys. 111, 1373 (1999)

"Dispersion of passive particles by a quasi-two-dimensional turbulent flow"

I. M. Sokolov and R.Reigada.
Phys. Rev. E 59(5), 5412 (1999)

"On the generalized Kramers problem with oscillatory memory friction"

R.Reigada, A.H.Romero, K.Lindenberg and J.M.Sancho.
J. Chem. Phys. 111(2), 676 (1999)

"Formation of Disclination Lines Near a Free Nematic Interface"

J. Ignés-Mullol, J. Baudry, L. Lejcek and P. Oswald.
Phys Rev E 59(1), 568 (1999)

"Velocity-Jump Instabilities in Hele-Shaw Flow of Associating Polymer-Solutions"

D. H. Vlad, J. Ignés-Mullol, et al.
Phys Rev E 60(4), 4423 (1999)

"Effect of Lattice-Defects on Hele-Shaw How over an Etched Lattice"

E. L. Decker, J. Ignés-Mullol, et al.
Phys. Rev. E 60(2), 1767 (1999)

1998


"Competitive evaporation in arrays of droplets"

A. M. Lacasta, J. M. Sokolov, J.M. Sancho and F. Sagués.
Phys. Rev. E 57, 6198 (1998)

"Propagating fronts in reaction-diffusion systems"

D. Vives, J. Armero, A. Martí, L. Ramírez-Piscina, J. Casademunt, J. M. Sancho and F. Sagués.
J. Mathem. Chem. 23, 239 (1998)

"Wave propagation in a medium with disordered excitability"

I. Sendiña-Nadal, A. P. Muñuzuri, D. Vives, V. Pérez-Muñuzuri,
J. Casademunt, L. Ramírez-Piscina, J. M. Sancho and F. Sagués.
Phys. Rev. Lett. 80, 5437 (1998)

"Percolation thresholds in chemical disordered excitable media"

I. Sendiña-Nadal, D. Roncaglia, D. Vives, V. Pérez-Muñuzuri, M. Gómez-Gesteira,
V. Pérez-Villar, J. Echave, J. Casademunt, L. Ramírez-Piscina and F. Sagués.
Phys. Rev. E 58, R1183 (1998)

"Numerical experiments in scalar diffusion under stochastic convection"

A. C. Martí, F. Sagués and J. M. Sancho.
App. Sci. Res. 59, 127-139 (1998)

"Pattern-Formation at a Nematic-Isotropic Liquid-Crystal Interface"

J. Ignés-Mullol and P. Oswald.
Phil. Mag. B 78(2), 167 (1998)

"Fracture-Like Patterns and Dendrites from Perturbed Saffman-Taylor Flows"

J. V. Maher and J. Ignés-Mullol.
Phil Mag B 78(2), 191 (1998)

1997


"Synthetic random flows: Generation and applications"

F. Sagués, J. M. Sancho and A. C. Martí.
Stoch. Dyn. (Eds. L. Schimansky and T. Paschel) Lect. Not. Phys. (Springer Verlag) 484, 346 (GERMANY) (1997)

"Fluctuation-dominated kinetics under regular and turbulent flows"

I. M. Sokolov, R. Reigada, F. Sagués, J. M. Sancho and A. Blumen.
Fractals and chaos in Chemical Engineering (Eds. M. Giona and G. Biardi) (World Scientific), 476 (1997)

"Fluctuation-dominated kinetics under stirring"

R. Reigada, F. Sagués, I. M. Sokolov, J. M. Sancho and A. Blumen.
Phys. Rev. Lett. 78, 741 (1997)

"Fingering instability in thin-layer electrodeposition: general trends and morphological transitions"

M. Q. López-Salvans, F. Sagués, J. Claret and J. Bassa.
J. Electranal. Chem. 421, 205 (1997)

"Langevin approach to generate synthetic turbulent flows"

A. C. Martí, J. M. Sancho, F. Sagués and A. Careta.
Phys. Fluids 9, 1078 (1997)

"Front dynamics in turbulent media"

A. Martí, F. Sagués and J. M. Sancho.
Phys. Fluids Comp. Sys. 9, 3851 (1997)

"Propagating fronts in chemical systems with coexisting multiple stationary states"

D. Vives, A. Careta and F. Sagués.
J. Chem. Phys. 107, 7894 (1997)

"Front propagation in spatially modulated media"

J. Armero, A. M. Lacasta, L. Ramírez-Piscina, J. Casademunt, J. M. Sancho and F. Sagués.
Phys. Rev. E 56, 5405 (1997)

"Diffusion in spatially and temporarily in homogeneous media: effects of turbulent mixing"

H. Lehr, F. Sagués and J. M. Sancho.
Phys. Rev. E 56, 1660 (1997)

"Reaction-diffusion fronts under stochastic advection"

A. C. Martí, F. Sagués and J. M. Sancho.
Phys. Rev. E 56, 1729 (1997)

"Further insights on dynamic morphological transitions in quasi-two-dimensional electrodeposition"

M. Q. López-Salvans, F. Sagués, J. Claret and J. Bassas.
Phys. Rev. E 56, 6869 (1997)

"Spatial organization in the A+B -> 0 reaction under confined-scale mixing"

R. Reigada, F. Sagués, I. M. Sokolov, J. M. Sancho and A. Blumen.
J. Chem. Phys. 107, 843 (1997)

"Wave competition in excitable modulated media"

I. Sendiña-Nadal, M. Gomez-Gesteira, V. Perez-Muñuzurri, V. Perez-Villar,
J. Armero, J. Ramírez-Piscina, F. Casademunt, F. Sagués and J. M. Sancho.
Phys. Rev. E 56, 6298 (1997)

1996


"Creixement fractal: als límits de la modelització"

F. Mas, J. Mach, P. P. Trigueros, J. Claret and F. Sagués.
Modelització Macroscòpica en Ciències Experimentals (Eds. M.Esteban et al.) (Institut d'Estudis Catalans), 115 (1996)

"Pattern and velocity selection of fronts propagating in modulated media"

J. Armero, A. Lacasta, L. Ramírez-Piscina, J. Casademunt, J. M. Sancho and F. Sagués.
Europhys. Lett. 33, 429 (1996)

"External fluctuations in front propagation"

J. Armero, J. M. Sancho, J. Casademunt, A. M. Lacasta, L. Ramírez-Piscina and F. Sagués.
Phys. Rev. Lett. 76, 3045 (1996)

"Finger-like aggregates in thin-layer electrodeposition"

M. Q. López-Salvans, P. P. Trigueros, S. Vallmitjana, J. Claret and F. Sagués.
Phys. Rev. Lett. 76, 4062 (1996)

"Spatial correlations and cross sections of clusters in the A+B -> 0 reaction"

R. Reigada, F. Sagués, I. M. Sokolov, J.M. Sancho and A. Blumen.
Phys. Rev. E 53, 3167 (1996)

"Diffusion in spatially and temporarily inhomogeneous media"

H. Lehr, F. Sagués and J. M. Sancho.
Phys. Rev. E 54, 5028 (1996)

"A+B -> 0 reaction with different initial patterns"

J. M. Sancho, A. H. Romero, K. Linderberg, F. Sagués, R. Reigada and A. M. Lacasta.
J. Phys. Chem. 100, 19066 (1996)

"Kinetics of the A+B -> 0 reaction under steady and turbulent flows"

R. Reigada, F. Sagués, I. M. Sokolov, J. M. Sancho and A. Blumen.
J. Chem. Phys. 105, 10925 (1996)

"Multiband properties of a fractal tree antenna generated by electrochemical deposition"

C. Puente, J. Claret, F. Sagués, J. Romeu, M. Q. López-Salvans and R. Pous.
Electr. Lett. 32, 2298 (1996)

"Experiments on Anisotropic Radial Viscous Fingering"

J. Ignes Mullol and J. V. Maher
Phys. Rev. E 53(4), 3788 (996)

1995


"Dynamics of reaction-diffusion interfaces under stochastic convection"

A. Careta, J.M. Sancho and F. Sagués.
New Trends in Pattern Formation in Active Nonlinear Media (Eds. V. Pérez Villar et al.)
Nonlinear Science, Series B (World Scientific) (SINGAPUR) 3, 261 (1995)

"Quasi-twodimensional electrodeposition: a summarized review on morphology and growth mechanisms"

L. López-Tomàs, J. Mach, P.P. Trigueros, F. Mas, J. Claret and F. Sagués.
Chaos Solitons & Fractals 6, 287 (1995)

"Two representations in multifractal analysis"

J. Mach, F. Mas and F. Sagués.
J. Phys. A: Mathem. Gen. 28, 5607 (1995)

"Phase separation dynamics under stirring"

A. Lacasta, J. M. Sancho and F. Sagués.
Phys. Rev. Lett. 75, 1791 (1995)

"Velocity Fluctuations of Fracturelike Disruptions of Associating Polymer-Solutions"

J.Ignés-Mullol, H.Zhao, et al.
Phys Rev E 51(2), 1338 (1995)


1994


"A Monte Carlo simulation of localized corrosion"

R. Reigada, F. Sagués and J. M. Costa.
J. Chem. Phys. 101(3), 2329 (1994)

"Een Monte Carlo-simulatie van het tunnelmechanisme in geval van lokale corrosie"
R. Reigada, F. Sagués and J. M. Costa.
Roestvast Staal 3, 19 (1994)

"Disordered Grown Systems: Generation and Fractal Analysis. Electrodeposition"
F.Sagués, L.López-Tomàs, J.Mach, R.Reigada, P.P.Trigueros, E.Vilaseca, J.Claret and F.Mas.
Int. J. Quant. Chem. 52, 375 (1994)

"Laplacian Multifractality of the Growth Probability Distribution in Electrodeposition"
J. Mach, F. Mas and F. Sagués.
Europhys. Lett. 25, 271 (1994)

"Influence of an inert electrolyte on the morphology of quasi-two-dimensional electrodeposits"
P. P. Trigueros, F. Sagués and J. Claret.
Phys. Rev. E 49, 4328 (1994)