Simultaneous Phase Separation and Pattern Formation in Chiral Active Mixtures

Chiral active particles, or self-propelled circle swimmers, from sperm cells to asymmetric Janus colloids, form a rich set of patterns, which are different from those seen in linear swimmers. Such patterns have mainly been explored for identical circle swimmers, while real-world circle swimmers, typically possess a frequency distribution. Here we show that even the simplest mixture of (velocity-aligning) circle swimmers with two different frequencies, hosts a complex world of superstructures: The most remarkable example comprises a microflock pattern, formed in one species, while the other species phase separates and forms a macrocluster, coexisting with a gas phase. Here, one species microphase-separates and selects a characteristic length scale, whereas the other one macrophase separates and selects a density. A second notable example, here occurring in an isotropic system, are patterns comprising two different characteristic length scales, which are controllable via frequency and swimming speed of the individual particles

Preface - Personal perspectives in nonlinear science : Looking back, looking forward

Peer reviewedPublisher PD

Large-scale fluctuation structures in plasma turbulence

The role of large-scale fluctuation structures in electrostatic drift-wave-type plasma turbulence is highlighted. In particular, well-defined laboratory experiments allow one to study the dynamics of drift wave mode structures as well as 'eddies' in drift wave turbulence. In the present paper we discuss the mutual relationships between observations made in linear magnetic geometry, purely toroidal geometry and magnetic confinement. The simplest structure, a saturated, nonlinear drift mode, is the starting point for a Ruelle-Takens-Newhouse transition route to chaos and weakly developed turbulence. Both spectral and phase space analysis are applied to characterize in detail the transition scenario, which is enforced due to an increased drive by the plasma equilibrium state. In addition to direct multi-probe observation, statistical approaches are most revealing for the systematic study of the spatiotemporal dynamics in fully developed drift wave turbulence. In particular, the propagation of large-scale 'eddy' structures is traced by conditional statistics methods. Finally, the control of drift wave turbulence by spatiotemporal synchronization is discussed

Preliminary design of a 100 kW turbine generator

The National Science Foundation and the Lewis Research Center have engaged jointly in a Wind Energy Program which includes the design and erection of a 100 kW wind turbine generator. The machine consists primarily of a rotor turbine, transmission, shaft, alternator, and tower. The rotor, measuring 125 feet in diameter and consisting of two variable pitch blades operates at 40 rpm and generates 100 kW of electrical power at 18 mph wind velocity. The entire assembly is placed on top of a tower 100 feet above ground level

Synchronization and Control in Intrinsic and Designed Computation: An Information-Theoretic Analysis of Competing Models of Stochastic Computation

We adapt tools from information theory to analyze how an observer comes to synchronize with the hidden states of a finitary, stationary stochastic process. We show that synchronization is determined by both the process's internal organization and by an observer's model of it. We analyze these components using the convergence of state-block and block-state entropies, comparing them to the previously known convergence properties of the Shannon block entropy. Along the way, we introduce a hierarchy of information quantifiers as derivatives and integrals of these entropies, which parallels a similar hierarchy introduced for block entropy. We also draw out the duality between synchronization properties and a process's controllability. The tools lead to a new classification of a process's alternative representations in terms of minimality, synchronizability, and unifilarity.Comment: 25 pages, 13 figures, 1 tabl

3D multi-nozzle system with dual drives highly potential for 3D complex scaffolds with multi-biomaterials

Recently, additive manufacturing is one of the most focused research topics due to its explosive development, especially in manufacturing engineering and medical science. In order to build 3D complex scaffolds with multi-biomaterials for clinical application, a new 3D multi-nozzle system with dual-mode drives, i.e. ejection and extrusion was developed. In this paper, much effort was made to gain fine control of droplet and excellent coordination during fabrication. Specifically, the parameters that influence the size and stability of droplet most was intensively studied. Considering that the biomaterials used in the future may have much difference in properties, the combination of parameters was investigated to facilitate the settings for certainsized droplets, which are potentially eligible for bio-printing. The dispensing nozzles can work well both in independent and convergent mode, which can be freely switched. Outstanding to the most currently used 3D bio-printing techniques, this system can fabricate scaffolds with multi-materials of both low viscosity (by pneumatic dispensing) and high viscosity (through motor extrusion). It is highly expected that this system can satisfy clinical application in the near future