Three-Dimensional Lattice Boltzmann Model Results for Complex Fluids Ordering

The kinetics of domain growth of fluid mixtures quenched from a disordered to a lamellar phase has been studied in three dimensions. We use a numerical approach based on the lattice Boltzmann method (LBM). A novel implementation for LBM which "fuses" the collision and streaming steps is used in order to reduce memory and bandwidth requirements. We find that extended defects between stacks of lamellae with different orientation dominate the late time dynamics

Power law velocity fluctuations due to inelastic collisions in numerically simulated vibrated bed of powder}

Distribution functions of relative velocities among particles in a vibrated bed of powder are studied both numerically and theoretically. In the solid phase where granular particles remain near their local stable states, the probability distribution is Gaussian. On the other hand, in the fluidized phase, where the particles can exchange their positions, the distribution clearly deviates from Gaussian. This is interpreted with two analogies; aggregation processes and soft-to-hard turbulence transition in thermal convection. The non-Gaussian distribution is well-approximated by the t-distribution which is derived theoretically by considering the effect of clustering by inelastic collisions in the former analogy.Comment: 7 pages, using REVTEX (Figures are inculded in text body) %%%Replacement due to rivision (Europhys. Lett., in press)%%

Solid state rectifier as terahertz detector

We present a new solid state rectifier, compatible with CMOS integrated circuit, suitable to direct conversion of terahertz radiation, at room temperature. The structure creates a rectenna, consists in a truncated conical helix extruded from a planar spiral and connected to a nanometric metallic whisker at one of its edges. The whisker reaches the gate of a MOS-FET transistor. Rectification can be obtained by the self-mixing effect occurring into the plasma waves generate underneath the gate. The proposed solution is easy to integrate with existing imaging systems. No need of scaling toward very scaled and costly technological node is required, since the plasma wave are not dependent on the gate extension. The remaining electronics should only provide the necessary integrated readout. A theoretical explanation of the self-mixing process, and TCAD simulations showing the onset of the DC potential are presented. An additional detector structure, the double barrier rectifier, is also presented for comparison

PROBABILITY DENSITY-FUNCTION OF TEMPERATURE-FLUCTUATIONS IN RAYLEIGH-BENARD CONVECTION

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The GLS approach to CMB map making.

{The field of Cosmic Microwave Background (CMB) data analysis is a smashing source of computational problems. Here we discuss the ROMA map making code. Originally designed to generate a map of the CMB anisotropy and polarization fields using optimal statistical methods, ROMA can be applied also to other microwave oriented surveys. The computational details of the subject will be set forth.