Papers by Aurora Hernandez-Machado
Micromachines, 2020
A coaxial flow focusing PDMS (polydimethylsiloxane) microfluidic device has been designed and man... more A coaxial flow focusing PDMS (polydimethylsiloxane) microfluidic device has been designed and manufactured by soft lithography in order to experimentally study a miscible inner flow. We studied a coaxially focused inner flow (formed by an aqueous fluorescein solution) which was fully isolated from all microchannel surfaces by an additional water outer flow. Different flow rates were used to produce a variety of flow ratios and a 3D reconstruction of the cross-section was performed using confocal microscope images. The results showed an elliptical section of the coaxially focused inner flow that changes in shape depending on the flow rate ratio applied. We have also developed a mathematical model that allows us to predict and control the geometry of the coaxially focused inner flow.
Deterministic versus noisy behavior in sidebranching
SPIE Proceedings, 2004
In this paper we study the sidebranching development of solidifying dendrites both experimentally... more In this paper we study the sidebranching development of solidifying dendrites both experimentally and by numerical integration of a phase-field model with a noise term. Our results support the idea that sidebranching is originated through the selective amplification of natural noise at the tip. The initial stages turn to be of crucial importance in the selection of the final noisy
Effective eigenvalue for the intensity correlations of single-mode and two-mode lasers
Physical Review A, 1987
Fluctuations in Domain Growth - Ginzburg-Landau Equations with Multiplicative Noise
Physical Review B, 1993
Pattern formation during mesophase growth in a homologous series
Physical Review E, 1996
Interfacial growth in driven diffusive systems
Physical Review A, 1989
Intensity correlation functions of dye lasers: Comparison of colored-gain-noise and colored-loss-noise models
Physical Review A, 1991
Theory for correlation functions of processes driven by external colored noise
Physical Review A, 1991
From lattice-gas models to nonlinear diffusion models: A derivation of macroscopic equations and fluctuations
Physical Review A, 1990
Interfacial growth in driven Ginzburg-Landau models: Short and long-time dynamics
Journal of Statistical Physics, 1994
ABSTRACT
Phase separation dynamics in driven diffusive systems
Journal of Statistical Physics, 1992
We study phase separation dynamics in a driven diffusive system. Our simulations are based on the... more We study phase separation dynamics in a driven diffusive system. Our simulations are based on the Cahn-Hilliard equation with an additional flux term due to an external field. We study the dynamical scaling parallel and perpendicular to the field. A crossover is observed from isotropic domains at early times to extremely anisotropic domains at later times. We find that the
Journal of Crystal Growth, 1998
An anisotropic heat diffusion coefficient is introduced in order to study some interfacial growth... more An anisotropic heat diffusion coefficient is introduced in order to study some interfacial growth phenomena. This anisotropy has been incorporated in a phase field model which has been studied numerically to reproduce some fundamental solidification situations (needle crystal growth) as well as the dynamics of a nematic-smectic-B interface. As a general result, we find that dendrites grow faster in the lower heat diffusion direction. Simulation results are compared with experiments with remarkable qualitative agreement.
Interface Equation and Viscosity Contrast in Hele-Shaw Flow
International Journal of Modern Physics B, 1992
We derive an integro-differential equation for the evolution of the interface separating two immi... more We derive an integro-differential equation for the evolution of the interface separating two immiscible viscous fluids in a Hele-Shaw cell with a channel geometry, for arbitrary viscosity contrast. Our equation differs from a previous one obtained by a vortex-sheet formulation of the problem, in that the normal component of the interface velocity is formally decoupled from the gauge-dependent tangential part. The result is thus a closed integral equation for the normal velocity. We briefly comment on the advantages of such a formulation and implement an alternative computational algorithm based on it. Preliminary numerical results confirm a highly inefficient finger competition in the zero viscosity contrast limit.
The Role of Noise in Sidebranching Development
Fluctuation and Noise Letters, 2004
In this paper we study the sidebranching development of solidifying dendrites both experimentally... more In this paper we study the sidebranching development of solidifying dendrites both experimentally and by numerical integration of a phase-field model with a noise term. Our results support the idea that sidebranching is originated through the selective amplification of natural noise at the tip. The initial stages turn to be of crucial importance in the selection of the final noisy shape. However, our results suggest that after the stochastic initial disturbance, a deterministic mechanism dominates the growth and screening-off process of sidebranching.
Zeitschrift f�r Physik B Condensed Matter, 1989
The steady-state correlation functions of non-linear stochastic processes driven by parametric no... more The steady-state correlation functions of non-linear stochastic processes driven by parametric noise are studied. A systematic method proposed by Nadler and Schulten is applied beyond the lowest order for the first time in this context. It is reformulated in a way which admits generalization to noises other than Gaussian and white. The explicit results obtained close to the instability point for the Verhulst model with Gaussian white noise improve considerably those previously obtained by continued-fraction techniques.
Correlation functions of non-linear nuclear reactor models
Annals of Nuclear Energy, 1985
Abstract The steady-state correlation function of a non-linear point nuclear reactor model with i... more Abstract The steady-state correlation function of a non-linear point nuclear reactor model with instantaneous temperature feedback, reactivity fluctuations and neglection of delayed neutrons is calculated by means of a continued fraction expansion method. Near criticality, ...
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Papers by Aurora Hernandez-Machado