Mancini-Maza, H. L. (Hector Luis)
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- Experimental dynamics in magnetic field-driven flows compared to thermoconvective convection(The Royal Society, 2015) Cortés-Dominguez, I. (Iván); Burguete, J. (Javier); Mancini-Maza, H. L. (Hector Luis)We compare the dynamics obtained in two intermediate aspect ratio (diameter over height) experiments. These systems have rotational symmetry and consist of fluid layers that are destabilized using two different methods. The first one is a classical Bénard–Marangoni experiment, where the destabilizing forces, buoyancy and surface tension, are created by temperature gradients. The second system consists of a large drop of liquid metal destabilized using oscillating magnetic fields. In this configuration, the instability is generated by a radial Lorentz force acting on the conducting fluid. Although there are many important differences between the two configurations, the dynamics are quite similar: the patterns break the rotational symmetry, and different azimuthal and radial wavenumbers appear depending on the experimental control parameters. These patterns in most cases are stationary, but for some parameters they exhibit different dynamical behaviours: rotations, transitions between different solutions or cyclic connections between different patterns.
- Periodicity characterization of the nonlinear magnetization dynamics(AIP, 2020) Laroze, D. (David); Suárez, O.J. (O. J.); Cabanas, A.M. (A.M.); Pérez, L.M. (L. M.); Bragard, J. (Jean); Mancini-Maza, H. L. (Hector Luis); Vélez, J.A. (J.A.)In this work, we study numerically the periodicity of regular regions embedded in chaotic states for the case of an anisotropic magnetic particle. The particle is in the monodomain regime and subject to an applied magnetic field that depends on time. The dissipative Landau–Lifshitz–Gilbert equation models the particle. To perform the characterization, we compute several two-dimensional phase diagrams in the parameter space for the Lyapunov exponents and the isospikes. We observe multiple transitions among periodic states, revealing complex topological structures in the parameter space typical of dynamic systems. To show the finer details of the regular structures, iterative zooms are performed. In particular, we find islands of synchronization for the magnetization and the driven field and several shrimp structures with different periods.
- Pattern formation without heating in an evaporative convection experiment(2004) Maza-Ozcoidi, D. (Diego); Mancini-Maza, H. L. (Hector Luis)Abstract. – We present an evaporation experiment in a single fluid layer reproducing conditions of volatile fluids in nature. When latent heat associated to the evaporation is large enough, the heat flow through the free surface of the layer generates temperature gradients that can destabilize the conductive motionless state giving rise to convective cellular structures without any external heating. Convective cells can be then observed in the transient range of evaporation from an initial depth value to a minimum threshold depth, after which a conductive motionless state appears until the evaporation finishes with an unwetting sequence. The sequence of convective patterns obtained here without heating is similar to that obtained in B´enard-Marangoni convection. This work presents the sequence of spatial bifurcations as a function of the layer depth. The transition between square-to-hexagonal pattern, known from non-evaporative experiments, is obtained here with a similar change in wavelength.
- Proyectos y actividades del CRYF(2007) Mancini-Maza, H. L. (Hector Luis)
- Asymmetric coupling effects in the synchronization of spatially extended chaotic systems(2003) Boccaletti, S. (S.); Bragard, J. (Jean); Mancini-Maza, H. L. (Hector Luis)We analyze the effects of asymmetric couplings in setting different synchronization states for a pair of unidimensional fields obeying complex Ginzburg-Landau equations. Novel features such as asymmetry enhanced complete synchronization, limits for the appearance of phase synchronized states, and selection of the final synchronized dynamics are reported and characterized.
- Comentarios sobre la cosmovisión científica en Mariano Artigas(Universidad Nicolás Copérnico de Torun, 2014) Mancini-Maza, H. L. (Hector Luis)Algunos conceptos de uso científico desempeñan un papel principal en el pensamiento de Mariano Artigas. Palabras como “orden”, “dinamismo”, “actividad”, “caos”, “azar”, “auto-organización”, “pautas”, “estructuras”, “emergencia” o “complejidad”, que también son de uso corriente en otros ámbitos del pensamiento, fueron utilizadas para construir lo que M. Artigas llama “la cosmovisión científica actual”, elemento básico sobre el cual discute la existencia de puentes filosóficos entre la ciencia y la fe. Desde los años en los que escribió su obra hasta hoy, algunos de esos conceptos tuvieron un intenso desarrollo que aún no ha concluido. A pesar de eso, muchas de esas palabras poseen hoy un alto grado de maduración, precisión y estabilidad que hace conveniente su discusión. En este trabajo se discute el concepto de cosmovisión científica en la obra de Artigas, en relación con algunos de los términos que utiliza. Resulta necesario destacar que a pesar de la evolución científica del significado de esos conceptos, los cambios no afectan la perspectiva global desde la cual Artigas presentó sus conclusiones generales sobre la relación entre ciencia y fe, que siguen siendo válidas y fructíferas.
- Complexity measures for multi-dimensional and chaotical sources of information(2015) Vidal, G. (Gerard); Mancini-Maza, H. L. (Hector Luis)Abstract. We apply a modified LMC complexity measure to an information source. The source is modeled by two identical Takens-Bogdanov equations synchronized, bi-directionally coupled and perturbed by a harmonic signal. In this system, when the frequency of the signal is tuned the complexity of the system changes. The aim of the work is to show that with a modification on the interpretation of the LMC measure, we can obtain an extensive measure that can be applied to measure the complexity of completely unknown systems. As an example, we apply this procedure to a high-dimensional system with chaotical behavior.
- Synchonization between two Hele-Shaw cells(2004) Bernardini, A. (A.); Bragard, J. (Jean); Mancini-Maza, H. L. (Hector Luis)Abstract. Complete synchronization between two Hele-Shaw cells is exam- ined. The two dynamical systems are chaotic in time and spatially extended in two dimensions. It is shown that a large number of connectors are needed to achieve synchronization. In particular, we have studied how the number of connectors influences the dynamical regime that is set inside the Hele-Shaw cells.
- Frecuency entrainment of nonautonomous chaotic oscillators(2004) Bove, I. (I.); Boccaletti, S. (S.); Bragard, J. (Jean); Mancini-Maza, H. L. (Hector Luis); Kurths, J. (J.)We give evidence of frequency entrainment of dominant peaks in the chaotic spectra of two coupled chaotic nonautonomous oscillators. At variance with the autonomous case, the phenomenon is here characterized by the vanishing of a previously positive Lyapunov exponent in the spectrum, which takes place for a broad range of the coupling strength parameter. Such a state is studied also for the case of chaotic oscillators with illdefined phases due to the absence of a unique center of rotation. Different phase synchronization indicators are used to circumvent this difficulty.
- Phase Clustering and Collective Behaviors in Globally Coupled Map Lattices due to mean Filed Effects(2000) Boccaletti, S. (S.); Maza-Ozcoidi, D. (Diego); Mancini-Maza, H. L. (Hector Luis)We describe the emergence of phase clustering and collective behaviors in an ensemble of chaotic coupled map lattices, due to a mean eld interaction. This kind of interaction is responsible for the appearence of a collective state, wherein the mean eld evolution of each lattice undergoes a periodic behavior in space. We analyze the transition to such a state in an ensemble of one-dimensional lattices of logistic maps, showing that the resulting behavior cooperatively maximizes the energy of the mean eld activity.