Linear response analysis in the nonequilibrium steady state (Gaussian regime) provides two independent fluctuation-response relations. One, in the form of the symmetric matrix, manifests the departure from the equilibrium formula through the quantity so-called irreversible circulation. The other, in...

We propose an extension of the nonequilibrium invaded cluster (IC) algorithm, which reestablishes a correct scaling of fluctuations at criticality and also self-adjusts to the critical temperature. We show that by introducing a single constraint to the intrinsic quantity of the IC algorithm the temp...

We investigate a recently proposed non-Markovian random walk model characterized by loss of memories of the recent past and amnestically induced persistence. We report numerical and analytical results showing the complete phase diagram, consisting of four phases, for this system: (i) classical nonpe...

The diffusive relaxation of a colloidal fluid adsorbed in a porous medium depends on many factors, including the concentration and composition of the adsorbed colloidal fluid, the average structure of the porous matrix, and the nature of the colloid-colloid and colloid-substrate interactions. A simp...

We experimentally investigated statistical properties of side branches of quasi-two-dimensional NH₄Cl dendritic crystals. The height distributions of the side branches and their number density exhibit scale-invariant power laws. The results are in good agreement with the results of numerical simul...

KIF1A kinesins are single-headed motor proteins which move on cylindrical nanotubes called microtubules (MTs). A normal MT consists of 13 protofilaments on which the equispaced motor binding sites form a periodic array. The collective movement of the kinesins on a MT is, therefore, analogous to vehi...

Proteins acting as molecular machines can undergo cyclic internal conformational motions that are coupled to ligand binding and dissociation events. In contrast to their macroscopic counterparts, nanomachines operate in a highly fluctuating environment, which influences their operation. To bridge th...

Dynamics of molecular motors that move along linear lattices and interact with them via reversible destruction of specific lattice bonds is investigated theoretically by analyzing exactly solvable discrete-state “burnt-bridge” models. Molecular motors are viewed as diffusing particles that can a...

Active cellular transport is a fundamental mechanism for protein and vesicle delivery, cell cycle, and molecular degradation. Viruses can hijack the transport system and use it to reach the nucleus. Most transport processes consist of intermittent dynamics, where the motion of a particle, such as a ...

We show how accurate kinetic information, such as the rates of protein folding and unfolding, can be extracted from replica-exchange molecular dynamics (REMD) simulations. From the brief and continuous trajectory segments between replica exchanges, we estimate short-time propagators in conformation ...

The complex dynamics of intracellular calcium regulates cellular responses to information encoded in extracellular signals. Here we study the encoding of these external signals in the context of the Li-Rinzel model. We show that by control of biophysical parameters the information can be encoded in ...

We demonstrate the microscopic equivalent of a step-stress rheological measurement. An optical torque is applied to a birefringent wax microdisk embedded in gelatin, a highly entangled viscoelastic biopolymer, using circularly polarized laser tweezers. By increasing the laser power and measuring the...

We introduce a stochastic model of growing networks where both the number of new nodes which join the network and the number of connections vary stochastically. We provide an exact mapping between this model and the zero-range process, and calculate analytically the degree distribution for any given...

The scaling properties of spectra of real world complex networks are studied by using the wavelet transform. It is found that the spectra of networks are multifractal. According to the values of the long-range correlation exponent, the Hust exponent H , the networks can be classified into three typ...

In order to explain the empirical evidence that the dynamics of human activity may not be well modeled by Poisson processes, a model based on queuing processes was built in the literature [A. L. Barabasi, Nature (London) 435, 207 (2005)]. The main assumption behind that model is that people execute ...

In a region in phase space where there is a chaotic saddle, all initial conditions will escape from it after a transient with the exception of a set of points of zero Lebesgue measure. The action of an external noise makes all trajectories escape faster. Attempting to avoid those escapes by applying...

We address the longstanding problem of recovering dynamical information from noisy acoustic emission signals arising from peeling of an adhesive tape subject to constant traction velocity. Using the phase space reconstruction procedure we demonstrate the deterministic chaotic dynamics by establishin...

We study scarring phenomena in open quantum systems. We show numerical evidence that individual resonance eigenstates of an open quantum system present localization around unstable short periodic orbits in a similar way as their closed counterparts. The structure of eigenfunctions around these class...

This paper reports the control of spatiotemporal intermittency in an electroconvective system in a nematic liquid crystal. In the spatiotemporal intermittency, an ordered structure [the defect lattice (DL)] coexists with turbulence. Control of the spatiotemporal intermittency, in which the turbulent...

We study the spatiotemporal properties of coherent states (peaks, holes, and fronts) in a bistable activator-inhibitor system that exhibits biochemical saturated autocatalysis, and in which fronts do not preserve spatial parity symmetry. Using the Gierer-Meinhardt prototype model, we find the condit...

We consider a general model of self-propelling particles interacting through a pairwise attractive force in the presence of noise and communication time delay. Previous work by Erdmann [Phys. Rev. E 71, 051904 (2005)] has shown that a large enough noise intensity will cause a translating swarm of i...

Patterns in dissipative systems with weakly broken symmetry are studied based upon the simplest canonical equation (generalized Nikolaevskiy model). A generic cubic dispersion equation governing stability of steady spatially periodic patterns is derived and analyzed. A domain of stable states in the...

Three-dimensional (3D) ac electro-osmotic (ACEO) pumps have recently been developed that are much faster and more robust than previous planar designs. The basic idea is to create a “fluid conveyor belt” by placing opposing ACEO slip velocities at different heights. Current designs involve electr...

Inertial particles advected in chaotic flows often accumulate in strange attractors. While moving in these fractal sets they usually approach each other and collide. Here we consider inertial particles aggregating upon collision. The new particles formed in this process are larger and follow the equ...

The dynamic resistance of a sphere with a general inhomogeneous slip boundary condition is analyzed in Newtonian unbounded uniform flow at low Reynolds number. The boundary condition is treated as a perturbation to a homogeneous sphere, assuming that the slip length magnitude b is much smaller tha...

We study near-wall streaks that form herringbonelike patterns in Taylor-Couette turbulence and in counter-rotating Taylor-Couette turbulence through three-dimensional direct numerical simulations. The orientation, axial distribution, onset, and tilting angle of these streaks are characterized.

An experiment on LULI 2000 laser devoted to density determination of shocked plastic from a two-dimensional monochromatic x-ray radiography is presented. A spherical quartz crystal was set to select the He-α line of vanadium at 2.382   Å and perform the image of the main target. Rear side...

The hallmark of nonlinear complexity phenomena in magnetohydrodynamic and plasma turbulence as well as all natural sciences is the appearance of intermittent fluctuating events. We introduce here a unique procedure that is both physically explicable and quantitatively accurate in deciphering the mul...

We derive an analytic formula for the lateral dynamics of solitons in a general inhomogeneous nonlinear media, and show that it can be valid over tens of diffraction lengths. In particular, we show that solitons centered at a lattice maximum can be “mathematically unstable” but “physically sta...

We rigorously derive a dramatically simplified kinetic model for fluids with internal degrees of freedom. With proper discretization in velocity space, the model leads to a lattice Boltzmann model for polyatomic gases. The macroscopic recovery of correct hydrodynamics is theoretically shown and nume...

KIF1A kinesins are single-headed motor proteins which move on cylindrical nanotubes called microtubules (MTs). A normal MT consists of 13 protofilaments on which the equispaced motor binding sites form a periodic array. The collective movement of the kinesins on a MT is, therefore, analogous to vehi...

Lipid membranes play a fundamental role in vital cellular functions such as signal transduction. Many of these processes rely on lateral diffusion within the membrane, generally a complex fluid containing ordered microdomains. However, little attention has been paid to the alterations in transport d...

The origin of diffusive transport of light in dry foams is still under debate. In this paper, we consider the random walks of photons as they are reflected or transmitted by liquid films according to the rules of ray optics. The foams are approximately modeled by three-dimensional Voronoi tessellati...

We extend the formalism of the thermodynamic two-time Green’s functions to nonextensive quantum statistical mechanics. Working in the optimal Lagrangian multiplier representation, the q -spectral properties and the methods for a direct calculation of the two-time q Green’s functions and the r...

We follow the dynamics of an ensemble of interacting self-propelled motorized particles in contact with an equilibrated thermal bath. We find that the fluctuation-dissipation relation allows for the definition of an effective temperature that is compatible with the results obtained using a tracer pa...

A theoretical approach to calculate the correlation functions in binary hard-sphere (HS) solid mixtures is developed. The method is motivated by the theory of correlations in one-component HS solids [Rascon , Phys. Rev. E 54, 1261 (1996)] and the Kirkwood-Buff theory for solutions. Combined with the...

Usually in the presence of a background noise an increased effort put in controlling a system stabilizes its behavior. Rarely it is thought that an increased control of the system can lead to a looser response and, therefore, to a poorer performance. Strikingly there are many systems that show this ...

In this paper, we investigate the dynamics of synchronous totally asymmetric exclusion processes on lattices with a multiple-input–single-output (MISO) junction, which consists of m subchains for the input and one main chain for the output. A MISO junction is a type of complex geometry that is r...

The Green-Kubo relation for two models of granular gases is discussed. In the Maxwell model in any dimension, the effective temperature obtained from the Green-Kubo relation is shown to be frequency independent and equal to the average kinetic energy, known as the granular temperature. In the second...

We study the brittle fragmentation of spheres by using a three-dimensional discrete element model. Large scale computer simulations are performed with a model that consists of agglomerates of many particles, interconnected by beam-truss elements. We focus on the detailed development of the fragmenta...

Spin-echo small-angle neutron scattering is able to characterize powders in terms of their density-density correlation function. Here we present a microstructural study on a fine cohesive powder undergoing uniaxial compression. As a function of compression, we measure the autocorrelation function of...

We present extensive Monte Carlo simulations for the thermodynamic and structural properties of a planar bilayer of dipolar hard spheres for a wide range of densities, dipole moments, and layer separations. Expressions for the stress and pressure tensors of the bilayer system are derived. For all th...

We study electroconvection patterns that appear above the splay Fréedericksz transition in a bent-core nematic liquid crystal with positive dielectric and negative conductivity anisotropy. In contrast to most of the previously observed convection rolls in nematics, they are not shadowgraph patterns...

An analytical expression for the synchronization time in coupled-map networks is given. By means of the expression, the synchronization time for any given network can be predicted accurately. Furthermore, for networks in which the distributions of nontrivial eigenvalues of coupling matrices have som...

We present an experimental study of a different pattern-forming instability occurring when a ferrofluid droplet is immersed in a thin layer of a nonmagnetic fluid, and subjected to a uniform perpendicular magnetic field. The formation of intriguing interfacial structures is observed, and the develop...

The percolation properties and permeability of a group of anisotropic three-dimensional fracture networks are studied numerically. Finite-size scaling is used to extrapolate the percolation thresholds of infinite networks in three spatial directions, i.e., X , Y , and Z directions. The influence...

Three-dimensional (3D) ac electro-osmotic (ACEO) pumps have recently been developed that are much faster and more robust than previous planar designs. The basic idea is to create a “fluid conveyor belt” by placing opposing ACEO slip velocities at different heights. Current designs involve electr...

Recent experiments on imbibition in columnar geometries show interfacial fluctuations whose dynamic scaling is not compatible with the usual nonlocal model governed by surface tension that results from a macroscopic description. To explore this discrepancy, we exhaustively analyze numerical integrat...

We analyze the stability of the plane Couette flow of a Newtonian fluid past an incompressible deformable solid in the creeping flow limit where the viscous stresses in the fluid (of the order η_fV∕R ) are comparable with the elastic stresses in the solid (of the order G ). Here, η_f is the fl...

Steady two-layer thin-film planar flow under gravity is investigated theoretically in this study. The film is assumed to emerge out of a channel and flow over a straight plate. The interplay among inertia, viscous and surface or interfacial tension is emphasized. It is found that the film and interf...

We investigate the short-range structure in strongly coupled fluidlike plasmas using the hypernetted chain approach generalized to multicomponent systems. Good agreement with numerical simulations validates this method for the parameters considered. We found a strong mutual impact on the spatial arr...

We investigate the crystallization rate of a one-component plasma (OCP) in the context of classical nucleation theory. From our derivation of the free energy of an arbitrary distribution of solid clusters embedded in a liquid phase, we derive the steady-state nucleation rate of an OCP as a function ...

We have characterized the plasma produced by a picosecond laser pulse using x-ray spectroscopy. High-resolution high-sensitivity spectra of K -shell emission from a Ti plasma have been obtained, showing a strong contribution from multiply ionized ions. Hydrodynamic and collisional-radiative codes a...

We present a methodology for the finite-element discretization of nanoscaled semiconductor devices with atomic resolution. The meshing strategy is based on the use of patterns to decompose the unit cell of the underlying crystallographic structures producing unstructured tetrahedral meshes. The unit...

The Berezinskii-Kosterlitz-Thouless like continuous phase transition observed in the three-spin interaction model is discussed. The relevant field theory describes the topological defects involved and enables us to perform the renormalization-group analysis. Based on it, we shall propose the finite-size-scaling ansatz for the helicity modulus which exhibits the exponent [`(n)]=3/5 for the correlation length in the disordered phase. We perform the Monte-Carlo simulations to confirm the ansatz. Also, we argue its relevance to the ground-state phase transition in the quantum spin chain.

Using methods of statistical physics, we study the average number and kernel size of general sparse random matrices over GF(q), with a given connectivity profile, in the thermodynamical limit of large matrices. We introduce a mapping of GF(q) matrices onto spin systems using the representation of the cyclic group of order q as the q-th complex roots of unity. This representation facilitates the derivation of the average kernel size of random matrices using the replica approach, under the replica symmetric ansatz, resulting in saddle point equations for general connectivity distributions. Numerical solutions are then obtained for particular cases by population dynamics. Similar techniques also allow us to obtain an expression for the exact and average number of random matrices for any general connectivity profile. We present numerical results for particular distributions.

We derive exact results for the spectral density S(w) of the output of the Preisach model, a standard model for complex, nonlocal hysteresis. We obtain general results for uncorrelated input signals with arbitrary input and Preisach densities. It is shown analytically that uncorrelated input signals are transformed into output exhibiting long-time correlations. For the simplest example of uniform input and Preisach distributions we prove that correlations decay asymptotically with a t-3 power law corresponding to a logarithmic low frequency divergence of the second derivative of the spectrum S(w). A simpler expression for symmetric Preisach models is also obtained, which is discussed in detail in Part II showing that long-time tails or even 1/f-noise are general features of this class of models.

The Preisach model with symmetric elementary hysteresis loops and uncorrelated input is treated analytically in detail. It is shown that the appearance of long-time tails in the output correlations is a quite general feature of this model. The exponent h of the algebraic decay t-h, which my take any positive value, is determined by the tails of the input and the Preisach density. We identify the system classes leading to identical algebraic tails. These results imply the occurrence of 1/f-noise for a large class of hysteretic systems.

The problem of how to reconstruct the parameters of a stochastic nonlinear dynamical system when these are time-varying is considered in the context of online decoding of physiological information from neuron signaling activity. To model the spiking of neurons, a set of FitzHugh-Nagumo (FHN) oscillators is used. It is assumed that only a fast dynamical variable can be detected for each neuron, and that the monitored signals are mixed by an unknown measurement matrix. The Bayesian framework introduced in Paper I (immediately preceding paper) is applied both for reconstruction of the model parameters and elements of the measurement matrix, and for inference of the time-varying parameters in the non-stationary system. It is shown that the proposed approach is able to reconstruct unmeasured (hidden) slow variables of the FHN oscillators, to learn to model each individual neuron, and to track continuous, random and step-wise variations of the control parameter for each neuron in real time.

A general Bayesian framework is introduced for the inference of time-varying parameters in non-stationary, nonlinear, stochastic dynamical systems. Its convergence is discussed. The performance of the method is analyzed in the context of detecting signalling in a system of neurons modeled as FitzHugh-Nagumo (FHN) oscillators. It is assumed that only fast action potentials for each oscillator mixed by an unknown measurement matrix can be detected. It is shown that the proposed approach is able to reconstruct unmeasured (hidden) variables of the FHN oscillators, to determine the model parameters, to detect stepwise changes of control parameters for each oscillator, and to follow continuous evolution of the control parameters in the adiabatic limit.

We present the experimental and numerical study of a method for detecting aperiodic binary signals in a bistable, vertical cavity surface emitting laser (VCSEL). The method uses the phenomenon of vibrational resonance, in presence of a fixed level of noise. We show that the addition of a periodic signal with a period much shorter than the bit duration of the aperiodic input signal allows to significantly increase the cross-correlation coefficient between the input and the output, as well as to substantially decrease the bit error rate. The experimental observation of a time lag between the input and the output of the VCSEL due the high-frequency modulation is reported. The effect of an asymmetry of the bistable quasipotential on the detection is also analyzed. The numerical results of simulations in a simple model are in qualitative agreement with the experiment.

We investigate the energetics of a Brownian motor driven by position dependent temperature, commonly known as the Büttiker-Landauer motor. Overdamped models (M=0) predict that the motor can attain Carnot efficiency. However, the overdamped limit (M® 0), contradicts the previous prediction due to the kinetic energy contribution to the heat transfer. Using molecular dynamics simulation and numerical solution of the inertial Langevin equation, we confirm that the motor can never achieve Carnot efficiency and verify that the heat flow via kinetic energy diverges as M-1/2 in the overdamped limit. The reciprocal process of the motor, namely the Büttiker-Landauer refrigerator is also examined. In this case, the overdamped approach succeeds in predicting the heat transfer only when there is no temperature gradient. Its found that the Onsager symmetry between the motor and refrigerator does not suffer from the singular behavior of the kinetic energy contribution.

The statistics of the iso-height lines in (2+1)-dimensional Kardar-Parisi-Zhang (KPZ) model is shown to be conformal invariant and equivalent to those of self-avoiding random walks. This leads to a rich variety of new exact analytical results for the KPZ dynamics. We present direct evidence that the iso-height lines can be described by the family of conformal invariant curves called Schramm-Loewner evolution (or SLEk) with diffusivity k = 8/3. It is shown that the absence of the non-linear term in the KPZ equation will change the diffusivity k from 8/3 to 4, indicating that the iso-height lines of the Edwards-Wilkinson (EW) surface are also conformally invariant, and belong to the universality class of the domain walls in the O(2) spin model.

Equilibrium wetting of ethanol onto chemically patterned nanostripes has been investigated using environmental Atomic Force Microscopy in non-contact mode. The chemical patterns are composed of COOH terminated "wetting" regions and CH3 terminated "nonwetting" regions. A specially-designed environmental AFM chamber allowed for accurate measurements of droplet height as a function of the temperature offset between the substrate and a macroscopic ethanol reservoir. At saturation, the height dependence scales with droplet width according to w1/2, in excellent agreement with the Augmented Young Equation (AYE) modeled with dispersive, non-retarded surface potentials. At small under- and over-saturations, the AYE model accurately fits the data if an effective DT is used as a fitting parameter. There is a systematic difference between the measured DT and the values extracted from the fits to the data. In addition to static measurements, we present time-resolved measurements of the droplet height which enable the study of condensation/evaporation dynamics of nanometer-scale drops.

The compound 10OHF has a partially inverted phase sequence, unique among the series of the nOHF homologous compounds and all other known liquid crystals, with the smectic-C*FI2 (SmC*FI2) phase occurring at higher temperature than the smectic-C* (SmC*) phase. We present ellipsometric data to identify the phase sequences of 9OHF, 10OHF, 11OHF, and 12OHF. Binary mixtures of 10OHF with C11, a compound with the typical phase sequence among the smectic phases, show that the unusual phase sequence of 10OHF stabilizes upon mixing and that SmC*FI2 predominates over SmC* throughout the entire mixing phase diagram. In thin films of some mixtures, surface interactions induce a reentrant SmC*FI2-SmC*-SmC*FI2 transition in the rest of the film.

In the present work an operational recipe for the mean square displacement (MSD) determination, highlighting the connection between Elastic Incoherent Neutron Scattering (EINS) intensity profiles and the associated self-distribution function, is presented. The determination of the thermal behaviour of the total MSD and of its partial contributions is tested on EINS data collected by the backscattering spectrometer IN13 (ILL, Grenoble) on a model system such as PolyEthylene Glycol with a mean molecular weight of 400 Dalton (PEG 400).

We investigate the role of fluctuations in single molecule measurements of torque-link (t-lk) curves. For semiflexible polymers of finite persistence length ( i.e. polymers with contour length L comparable to the persistence length LP), the torque versus link curve in the constant torque (isotorque) ensemble is distinct from the one in the constant link (isolink) ensemble. Thus, one encounters the conceptually interesting issue of a "free energy of transition" in switching ensembles while making torque-link measurements. We predict the dependence on the semiflexibility parameter b = L/LP of this extra contribution to the free energy which shows up as an area in the torque-link plane. This can be tested against future torque-link experiments with single biopolymers. We bring out the inequivalence of torque-link curves for a stiff polymer and present explicit analytical expressions for the distinct torque-link relations in the two ensembles and the free energy difference in switching ensembles in this context. The predictions of our work can be tested against single molecule experiments on torsionally constrained biopolymers.

The shape of E. coli is approximately that of a cylinder with hemispherical caps. Since its size is not much larger than optical resolution it has been difficult to quantify deviations from this approximation. We show that one can bypass this limitation and obtain the cell shape with sub-pixel accuracy. The resulting contours are shown to deviate from the hemisphere-cylinder-hemisphere shape. In particular, the cell is weakly asymmetric. Its two caps are different from each other and the sides are slightly curved. Most cells have convex sides. We discuss our results in the light of several mechanisms that are involved in determining the shape of cells.

.} The development of a large non-coding fraction in eukaryotic DNA and the phenomenon of the code-bloat in the field of evolutionary computations show a striking similarity. This seems to suggest that (in the presence of mechanisms of code growth) the evolution of a complex code can't be attained without maintaining a large inactive fraction. To test this hypothesis we performed computer simulations of an evolutionary toy model for Turing machines, studying the relations among fitness and coding/non-coding ratio while varying mutation and code growth rates. The results suggest that, in our model, having a large reservoir of non-coding states constitutes a great (long term) evolutionary advantage. \end{quotation}

We present a simple model to explain the transition from the oscillatory to smooth propagation in brittle metallic glasses. We demonstrate that the smooth fracture propagation that is characteristic for higher temperature or higher crack opening velocities (for type 1 crack propagation) becomes unstable and oscillatory behavior is being observed. The characteristic feature size of the crack propagation may be at the nanometer scale and grows as the opening velocity decreases.

We systematically develop a technique for reconstructing the phase dynamics equations for coupled oscillators from data. For autonomous oscillators and for two interacting oscillators we demonstrate how phase estimates obtained from general scalar observables can be transformed to genuine phases. This allows us to obtain an invariant description of the phase dynamics in terms of the genuine, observable-independent phases. We discuss the importance of this transformation for characterization of strength and directionality of interaction from bivariate data. Moreover, we demonstrate that natural (autonomous) frequencies of oscillators can be recovered if several observations of coupled systems at different, yet unknown, coupling strengths are available. We illustrate our method by several numerical examples and apply it to a human electrocardiogram and to a physical experiment with coupled metronomes.

Effects of rapid stellar rotation on acoustic oscillation modes are poorly understood. We study the dynamics of acoustic rays in rotating polytropic stars and show using quantum chaos concepts that the eigenfrequency spectrum is a superposition of regular frequency patterns and an irregular frequency subset respectively associated with near-integrable and chaotic phase space regions. This opens new perspectives for rapidly rotating star seismology and also provides a new and potentially observable manifestation of wave chaos in a large scale natural system.

In this paper, the results of laboratory investigation about the flow behind the sphere in the range of 150 < Re < 300, where very interesting physical phenomenon occurs, are presented. After a first stationary transition where the flow breaks the axisymmetry, very controlled experiments allow to define a new threshold for second transition from stationary to unstable flow, which includes 3D peristaltic oscillations of the two trailing vortices prior to hairpins shedding. The new scenario has been proposed to explain the hairpin formation, as pieces of a counter-rotating longitudinal vortex. Hairpin shedding is suggested to be the result of oscillations, which are powerful enough, and reconnection of the trailing vortices.

The homogenization procedure is applied to the problem of wave propagation in the biphasic mode in porous media saturated with a Newtonian fluid. The local problems corresponding to the solid and fluid phases have been solved separately for complex three-dimensional media. The effective rigidity tensor, some effective coefficients, the dynamic permeability, the celerities and the attenuation of the three waves are systematically determined. The characteristic length L was successfully used to gather the results for the dynamic permeability as well as for the attenuation coefficients for all media.

In two independent articles, Escudier and Presti [J. Non-Newtonian Fluid Mech. 62, 291 (1996)] and Peixinho et al. [J. Non-Newtonian Fluid Mech. 128, 172 (2005)] studied experimentally the flow structure of a yield stress fluid in a cylindrical pipe. It was observed that the mean, i.e., time-averaged, velocity profiles were axisymmetric in the laminar and turbulent regimes, and presented an increasing asymmetry with increasing Reynolds number in the transitional regime. The present paper provides a three-dimensional description of this asymmetry from axial velocity profiles measurements at three axial positions and different azimuthal positions. The observed transitional flow suggests the existence of a robust nonlinear coherent structure characterized by two weakly modulated counter-rotating longitudinal vortices. This new state mediates the transition between laminar and turbulent flow.

Radiation hydrodynamics simulations were used to study the effect of plastic ablators in laser-driven shock experiments. The sensitivity to composition and equation of state was found to be 5-10% in ablation pressure. As was found for metals, a laser pulse of constant irradiance gave a pressure history which decreased by several percent per nanosecond. The pressure history could be made more constant by adjusting the irradiance history. The impedance mismatch with the sample gave an increase o(100%) in the pressure transmitted into the sample, for a reduction of several tens of percent in the duration of the peak load applied to the sample, and structured the release history by adding a release step to a pressure close to the ablation pressure. Algebraic relations were found between the laser pulse duration, the ablator thickness, and the duration of the peak pressure applied to the sample, involving quantities calculated from the equations of state of the ablator and sample using shock dynamics.

We analyze the properties of discrete breathers excited near the edge of a one-dimensional metamaterial created by a truncated array of nonlinear split-ring resonators. We study a crossover between nonlinear surface states and discrete breathers by analyzing the modes centered at finite distances from the array edge and demonstrate the existence of a novel class of nonlinear localized surface states, the so-called nonlinear Tamm states or surface breathers, which exhibit novel features that have no counterparts neither in the continuous systems nor in linear arrays.

We numerically investigate the negative index of refraction in a metamaterial composed of metallic split-ring resonators, which exhibits simultaneously negative permittivity and permeability without resorting to additional metallic wires. It is confirmed that, at the left-handed band, negative permittivity is generated in analogy to the cut-wire metamaterials and negative permeability comes from the antisymmetric resonant mode, which occurs at a frequency band about 3 times higher than the familiar magnetic resonance proposed by Pendry et al., and thus takes advantage for experimental realization of left-handed materials marching toward the infrared and even visible spectra.

Based on phonon Boltzmann equation, a lattice Boltzmann model for phonon hydrodynamics is developed. Both transverse and longitudinal polarized phonons that interact through normal and umklapp processes are considered in the model. The collision term is approximated by the relaxation time model where normal and umklapp processes tend to relax distributions of phonons to their corresponding equilibrium distribution functions – the displaced Planck distribution and the Planck distribution, respectively. A macroscopic phonon thermal wave equation (PTWE), valid in the second-sound mode, is derived through the technique of Chapman-Enskog expansion. Comparing with the dual-phase-lag (DPL) based thermal wave equation, PTWE has an additional 4-ordered spatial derivative term. Fundamentaldifference between the two models is discussed through examining apropagating thermal pulse in a single-phased medium and the transientand steady-state transport phenomena on a two-layered structuresubjected to different temperatures at boundaries. Results showtransport phenomena are significant different between the two models.The path of reduction mode of heat transfer from thermal wave todiffusion through approaching to in the DPLmodel is incompatible with any microscopic phonon propagating mode.Unlike the DPL model that only affects on the transient, inPTWE shows effects on phenomena at both transient andsteady state. With the intrinsic compatibility to microscopic state,discontinuous quantity, such as a jump of temperature at a boundary orat an interface, can be calculated naturally and straightforwardly bythe present lattice Boltzmann method.