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Lund Lauridsen posted an update 2 weeks, 3 days ago
This corrects the article DOI 10.1103/PhysRevE.98.013302.We explore the intriguing effects of the underlying star topological structure in the framework of Schelling’s segregation model with blocks. The significant consequences exerted by the star topology are both theoretically analyzed and numerically simulated with and without introducing a fraction of altruistic agents, respectively. The collective utility of the model with egoists alone can be optimized and the optimum stationary state is achieved with the underlying star topology of blocks. More surprisingly, once a proportion of altruists is introduced, the average utility gradually decreases as the fraction of altruists increases. This presents a sharp contrast to the results in Schelling’s model with a lattice topology of blocks. Furthermore, an adding-link mechanism is introduced to bridge the gap between the lattice and the star topologies and extend our analysis to more general scenarios. A scaling law of the average utility function is found for the star topology of blocks.The classical Rayleigh-Bénard convection (RBC) system is known to exhibit either subcritical or supercritical transition to convection in the presence or absence of rotation and/or magnetic field. However, the simultaneous exhibition of subcritical and supercritical branches of convection in plane layer RBC depending on the initial conditions, to the best of our knowledge, has not been reported so far. Here, we report the phenomenon of simultaneous occurrence of subcritical and supercritical branches of convection in overstable RBC of electrically conducting low Prandtl number fluids (liquid metals) in the presence of an external uniform horizontal magnetic field and rotation about the vertical axis. Extensive three-dimensional (3D) direct numerical simulations (DNS) and low-dimensional modeling of the system, performed in the ranges 750≤Ta≤3000 and 0 less then Q≤1000 of the Taylor number (Ta, strength of the Coriolis force) and the Chandrasekhar number (Q, strength of the Lorenz force), respectively, establish the phenomenon convincingly. Detailed bifurcation analysis of a simple 3D model derived from the DNS data reveals that a supercritical Hopf bifurcation and a subcritical pitchfork bifurcation of the conduction state are responsible for this. The effect of Prandtl number on these transitions is also explored in detail.Liquid crystal elastomers and glasses can have significant shape change determined by their director patterns. Cones deformed from circular director patterns have nontrivial Gaussian curvature localized at tips, curved interfaces, and intersections of interfaces. We employ a generalized metric compatibility condition to characterize two families of interfaces between circular director patterns, hyperbolic and elliptical interfaces, and find that the deformed interfaces are geometrically compatible. find more We focus on hyperbolic interfaces to design complex topographies and nonisometric origami, including n-fold intersections, symmetric and irregular tilings. The large design space of threefold and fourfold tiling is utilized to quantitatively inverse design an array of pixels to display target images. Taken together, our findings provide comprehensive design principles for the design of actuators, displays, and soft robotics in liquid crystal elastomers and glasses.We report experimental evidence of clogging due to the spontaneous development of hanging arches when a granular sample composed of spherical particles flows down a narrow vertical pipe. These arches, akin to the ones responsible for silo clogging, can only be possible due to the role of frictional forces; otherwise they will be unstable. We find that, contrary to the silo case, the probability of clogging in vertical narrow tubes does not decrease monotonically with the ratio of the pipe-to-particle diameters. This behavior is related to the clogging prevention caused by the spontaneous ordering of particles apparent in certain aspect ratios. More importantly, by means of numerical simulations, we discover that the interparticle normal force distributions broaden in systems with higher probability of clogging. This feature, which has been proposed before as a distinctive feature of jamming in sheared granular samples, suggests that clogging and jamming are connected in pipe flow.We study adsorption at periodically corrugated substrates formed by scoring rectangular grooves into a planar solid wall which interacts with the fluid via long-range (dispersion) forces. The grooves are assumed to be macroscopically long but their depth, width, and separations can all be molecularly small. We show that the entire adsorption process can be divided into three parts consisting of (i) filling the grooves by a capillary liquid; (ii) depinning of the liquid-gas interface from the wall edges; and (iii) unbinding of the interface from the top of the wall, which is accompanied by a rapid but continuous flattening of its shape. Using a nonlocal density functional theory and mesoscopic interfacial models all the regimes are discussed in some detail to reveal the complexity of the entire process and subtle aspects that affect its behavior. In particular, it is shown that the nature of the depinning phenomenon is governed by the width of the wall pillars (separating grooves), while the width of the grooves only controls the location of the depinning first-order transition, if present.A nematic liquid crystal confined to the surface of a sphere exhibits topological defects of total charge +2 due to the topological constraint. In equilibrium, the nematic field forms four +1/2 defects, located at the corners of a regular tetrahedron inscribed within the sphere, since this minimizes the Frank elastic energy. If additionally the individual nematogens exhibit self-driven directional motion, the resulting active system creates large-scale flow that drives it out of equilibrium. In particular, the defects now follow complex dynamic trajectories which, depending on the strength of the active forcing, can be periodic (for weak forcing) or chaotic (for strong forcing). In this paper we derive an effective particle theory for this system, in which the topological defects are the degrees of freedom, whose exact equations of motion we subsequently determine. Numerical solutions of these equations confirm previously observed characteristics of their dynamics and clarify the role played by the time dependence of their global rotation.