Damien Terebenec, Markus Mohr, Rainer Wunderlich
et al.
Abstract Understanding thermophysical properties such as surface tension ( σ ), total hemispherical emissivity ( ε ), specific heat capacity ( c p ) and viscosity ( η ) as a function of temperature is essential for optimizing the vitrification of bulk metallic glasses (BMGs). In this study, the thermophysical properties of liquid Vit106a were measured aboard the International Space Station (ISS) using the electromagnetic levitator (EML). The surface tension σ exhibited a similar value with other Zr-based BMG, with a weak temperature dependence described by σ(T) = 1.557–4.36 ×10 −5 × (T - 1106) N.m −1 . The viscosity temperature-dependence η(T) was analyzed using the Vogel–Fulcher–Tammann (VFT) equation, yielding a kinetic fragility parameter of D* = 9.8 at high temperature, compared to D* = 21.6 at low temperature, that indicates a fragile-to-strong transition characteristic of Zr-based metallic glass formers. XRD analysis confirms full crystallization of the sample, despite being cooled at a rate of 16 K.s⁻¹, over nine times faster than the critical cooling rate of 1.75 K.s⁻¹ reported in the literature. The crystallized sample reveals a heterogeneous distribution of binary intermetallic phases, including ZrAl 3 , Zr 2 Cu, Zr 2 Ni, ZrAl and Nb 2 Ni. These findings provide insights into the thermophysical behavior of liquid Vit106a for large-scale manufacturing but also raise important questions regarding its good glass-forming ability for larger casting thickness.
We propose here a delay differential equation that exhibits a new type of resonating oscillatory dynamics. The oscillatory transient dynamics appear and disappear as the delay is increased between zero to asymptotically large delay. The optimal height of the power spectrum of the dynamical trajectory is observed with the suitably tuned delay. This resonant behavior contrasts itself against the general behaviors where an increase of delay parameter leads to the persistence of oscillations or more complex dynamics.
A non-local model describing the growth of a tree-like transportation network with given allocation rules is proposed. In this model we focus on tree like networks, and the network transports the very resource it needs to build itself. Some general results are given on the viability tree-like networks that produce an amount of resource based on its amount of leaves while having a maintenance cost for each node. Some analytical studies and numerical surveys of the model in "simple" situations are made. The different outcomes are discussed and possible extensions of the model are then discussed.
A system of four coupled oscillators that exhibits unusual synchronization phenomena has been ana- lyzed. Existence of a one-way heteroclinic network, called heteroclinic ratchet, gives rise to uni-directional (de)synchronization between certain groups of cells. Moreover, we show that locking in frequency differ- ences occur when a small white noise is added to the dynamics of oscillators.
In this letter, by regarding finite-time stability as an inverse problem, we reveal the essence of finite-time stability and fixed-time stability. Some necessary and sufficient conditions are given. As application, we give a new approach for finite-time and fixed-time synchronization and consensus. Many existing results can be derived by the general approach.
In this paper, a bipartite consensus problem for a multi-agent system is formulated firstly. Then an event-based interaction rule is proposed for the multi-agent system with antagonistic interactions. The bipartite consensus stability is analyzed on the basis of spectral properties of the signed Laplacian matrix associated with multi-agent networks. Some simulation results are presented to illustrate the bipartite consensus with the proposed interaction rule.
A universal approach is proposed for suppression of collective synchrony in a large population of interacting rhythmic units. We demonstrate that provided that the internal coupling is weak, stabilization of overall oscillations with vanishing stimulation leads to desynchronization in a large ensemble of coupled oscillators, without altering significantly the essential nature of each constituent oscillator. We expect our findings to be a starting point for the issue of destroying undesired synchronization, e. g. desynchronization techniques for deep brain stimulation for neurological diseases characterized by pathological neural synchronization.
In this paper we define the canonical mixed extension of a decision form game. We motivate the necessity to introduce this concept and we show several examples about the new concept. In particular we focus our study upon the mixed equilibria of a finite decision form game. Many developments appear possible for applications to economics, physics, medicine and biology in those cases for which the systems involved do not have natural utility functions but are only capable to react versus the external actions.
An operator that governs the discrete time evolution of the velocity distribution of an out-of-equilibrium ideal gas will be presented. This nonlinear map, which conserves the momentum and the energy of the ideal gas, has the Maxwellian Velocity Distribution (MVD) as an asymptotic equilibrium. Moreover, the system displays the increasing of the entropy during the decay to the MVD.
We consider the nonlinear extension of the Kuramoto model of globally coupled phase oscillators where the phase shift in the coupling function depends on the order parameter. A bifurcation analysis of the transition from fully synchronous state to partial synchrony is performed. We demonstrate that for small ensembles it is typically mediated by stable cluster states, that disappear with creation of heteroclinic cycles, while for a larger number of oscillators a direct transition from full synchrony to a periodic or quasiperiodic regime occurs.
The network of 5823 cities of Mexico with a population more than 5000 inhabitants is studied. Our analysis is focused to the spectral properties of the adjacency matrix, the small-world properties of the network, the distribution of the clustering coefficients and the degree distribution of the vertices. The connection of these features with the spread of epidemics on this network is also discussed.
The calculation of a statistical measure of complexity and the Fisher-Shannon information in nuclei is carried out in this work. We use the nuclear shell model in order to obtain the fractional occupation probabilities of nuclear orbitals. The increasing of both magnitudes, the statistical complexity and the Fisher-Shannon information, with the number of nucleons is observed. The shell structure is reflected by the behavior of the statistical complexity. The magic numbers are revealed by the Fisher-Shannon information.
This paper is placed at the intersection-point between the study of theoretical computational models aimed at capturing the essence of genetic regulatory networks and the field of Artificial Embryology (or Computational Development). A model is proposed, with the objective of providing an effective way to generate arbitrary forms by using evolutionary-developmental techniques. Preliminary experiments have been performed.
In this work we present a model for evolving networks, where the driven force is related to the social affinity between individuals in a population. In the model, a set of individuals initially arranged on a regular ordered network and thus linked with their closest neighbors are allowed to rearrange their connections according to a dynamics closely related to that of the stable marriage problem. We show that the behavior of some topological properties of the resulting networks follows a non trivial pattern.
The LMC-complexity introduced by Lopez-Ruiz, Mancini and Calbet [Phys. Lett. A 209, 321-326 (1995)] is calculated for different physical situations: one instance of classical statistical mechanics, normal and exponential distributions, and a simplified laser model. We stand out the specific value of the population inversion for which the laser presents maximun complexity.
A two-dimensional cellular automaton model of traffic flow with open boundaries are investigated by computer simulations. The outflow of cars from the system and the average velocity are investigated. The time sequences of the outflow and average velocity have flicker noises in a jamming phase. The low density behavior are discussed with simple jam-free approximation.
Autoresonance is a phase locking phenomenon occurring in nonlinear oscillatory system, which is forced by oscillating perturbation. Many physical applications of the autoresonance are known in nonlinear physics. The essence of the phenomenon is that the nonlinear oscillator selfadjusts to the varying external conditions so that it remains in resonance with the driver for a long time. This long time resonance leads to a strong increase in the response amplitude under weak driving perturbation. An analytic treatment of a simple mathematical model is done here by means of asymptotic analysis using a small driving parameter. The main result is finding threshold for entering the autoresonance.
We investigate correlations among pitches in several songs and pieces of piano music by mapping them to one-dimensional walks. Two kinds of correlations are studied, one is related to the real values of frequencies while they are treated only as different symbols for another. Long-range power law behavior is found in both kinds. The first is more meaningful. The structure of music, such as beat, measure and stanza, are reflected in the change of scaling exponents. Some interesting features are observed. Our results demonstrate the viewpoint that the fundamental principle of music is the balance between repetition and contrast.
A parabolic stochastic PDE is studied analytically and numerically, when a bifurcation parameter is slowly increased through its critical value. The aim is to understand the effect of noise on delayed bifurcations in systems with spatial degrees of freedom. Realisations of the nonautonomous stochastic PDE remain near the unstable configuration for a long time after the bifurcation parameter passes through its critical value, then jump to a new configuration. The effect of the nonlinearity is to freeze in the spatial structure formed from the noise near the critical value.