We consider double-diffusive convection between two parallel plates and compute bounds on the flux of the unstably stratified species using the background method. The bound on the heat flux for Rayleigh–Bénard convection also serves as a bound on the double-diffusive problem (with the thermal Rayleigh number equal to that of the unstably stratified component). In order to incorporate a dependen...

In this paper, we investigate moment methods from a general point of view using an operator notation. This theoretical approach lets us explore the moment closure problem in more detail. This gives rise to a new idea, proposed in [14, 15], of how to improve the well-known PN approximations. We systematically develop a diffusive correction to the PN equations from the operator formulation — the ...

We present a novel mechanism of phase-dependent electric transport in diffusive normal metal-superconductor structures. We provide a detailed theoretical and numerical analysis of recent unexplained experiments essentially

The recent introduction of actuation mechanisms for microfluidic transport based on free surface flows raises a number of interesting questions involving efficient mixing configurations, especially in systems with small aspect ratios. This work investigates the characteristics of convective and diffusive mixing in continuous-mode streaming of thermocapillary microflows on chemically micropatter...

The response function of a homogeneous and dense hadronic system to a timedependent (baryon) vector potential is discussed for holographic dense QCD (D4/D8 embedding) both in the confined and deconfined phases. Confined holographic QCD is an uncompressible and static baryonic insulator at large Nc and large λ, with a gapped vector spectrum and a massless pion. Deconfined holographic QCD is a di...

Diffusive monitors have been used for workplace air monitoring for many years, and in many cases have been found to be valid and cost-effective alternatives to conventional pumped or ‘active’ samplers. The state of the art of diffusive sampling is reviewed briefly, with particular reference to workplace air monitoring, and the potential for using similar or adapted devices for measuring concent...

Oscillatory behaviour is essential for proper functioning of various physical and biological processes. However, diffusive coupling is capable of suppressing intrinsic oscillations due to the manifestation of the phenomena of amplitude and oscillation deaths. Here we present a scheme to revoke these quenching states in diffusively coupled dynamical networks, and demonstrate the approach in expe...

A time-domain numerical modeling of Biot poroelastic waves is presented. The viscous dissipation occurring in the pores is described using the dynamic permeability model developed by Johnson-Koplik-Dashen (JKD). Some of the coefficients in the Biot-JKD model are proportional to the square root of the frequency: in the time-domain, these coefficients introduce order 1/2 shifted fractional deriva...

We consider a system of random walks or directed polymers interacting with an environment which is random in space and time. It was shown by Imbrie and Spencer that in spatial dimensions three or above the behavior is diffusive if the directed polymer interacts weakly with the environment and if the random environment follows the Bernoulli distribution. Under the same assumption on the random e...

We consider reaction-diffusion systems on the infinite line that exhibit a family of spectrally stable spatially periodic wave trains u0(kx− ωt; k) that are parameterized by the wave number k. We prove stable diffusive mixing of the asymptotic states u0(kx + φ±; k) as x → ±∞ with different phases φ− 6= φ+ at infinity for solutions that initially converge to these states as x → ±∞. The proof is ...