CASTELLANOS MATA , Antonio

The main goal of this work is to model a homogeneous computer material with well-defined mechanical properties. To carry out the model material, an internal structure arranged in layers with different atom sizes is implemented using a simple interatomic law of Lennard-Jones type (LJ). We show that imposing an appropriate scaling law between the...

A set of one‐dimensional models, previously derived for liquid jets, is generalized to viscous liquid bridges by applying suitably modified boundary conditions at the anchoring disks. A linear analysis for small‐amplitude perturbations around the cylindrical static solution is performed. The oscillation frequencies and growth factors so...

Some years ago it was shown that gas-fluidized powders may transit from solidlike to fluidlike fluidization prior to bubbling, shedding light on a long-standing controversy on the nature of "homogeneous" fluidization. In this paper it is shown that some gas-fluidized powders may also transit from the fluidlike regime to elutriation, with full...

Fine particles agglomerate in the fluidized state due to the strength of interparticle attractive forces as compared to particle weight. Interparticle adhesion can be largely increased by consolidation stresses applied during powder handling. As a consequence, fragments of the consolidated powder may persist when the powder is fluidized, which...

La presente invención tiene por objeto un procedimiento de adsorción de CO2 que consiste en hacer pasar un flujo de gas con una concentración determinada de CO2 a través de un lecho de polvo dispuesto sobre una placa porosa en una cámara de fluidización,

We explore the role of gas viscosity in the behavior of gas-fluidized beds of fine powders by means of experimental measurements using nitrogen and neon as fluidizing gases, and theoretical considerations. The existence of a nonbubbling fluidlike regime has been recently observed in beds of fine powders fluidized with nitrogen. Our experiments...

The aim of this paper is to explore the capability of Discontinuous Galerkin Finite Element methods to solve numerically the charge transport equation in EHD convective flows, in both strong and weak injection regimes. These methods are especially suited to treat purely hyperbolic problems, as it is the charge transport equation in most EHD...

Isotropic packings of cohesive disks in 2D are studied by discrete, stress-controlled numerical simulations. Depending on the assembling process and on whether contacts possess rolling resistance (RR), configurations form under low pressure P with varying solid fraction Φ and fractal dimension d F describing small scale correlations below some...

Dispositivo y procedimiento para medir la cohesión de medios granulares finos. El objeto de la presente invención es un dispositivo automatizado para la medida de la cohesión de medios granulares finos (polvos). El aparato se basa en un procedimiento que

In flows of dry particulate systems, electric charge is generated on particle surfaces by their collision with walls and with other particles. Charge build-up on single particles can yield local charge values high enough to surpass the limiting electric field for corona discharge into the surrounding gas. Then, local charge is decreased to a...

An analysis of slender axisymmetric liquid columns is performed on the basis of one-dimensional models, recently derived and generalized here to include the effect of dielectric forces at the interface. The natural frequencies and stability criteria in the absence of gravity are obtained. Results are compared with the known exact linear...

An analysis of slender axisymmetric liquid bridges is performed on the basis of one-dimensional models recently derived, and generalized here to include the effect of dielectric forces at the interface. The natural frequencies and stability criteria in the absence of gravity are obtained. In the inviscid case, results are compared with the...

The time evolution of the problem of Electrohydrodynamic (EHD) convection in a liquid between two plates is analysed numerically. The equations are nondimensionalized using the ion drift velocity and the viscous time scales. Following the non-dimensionalisation of the respective model, two different techniques have been used to describe the...

The stability spectrum for a jet of perfectly insulating, viscous liquid subjected to a longitudinal electric field is obtained for axisymmetric perturbations. Both dielectric forces at the interface and viscous dissipation produce lower growth factors for all the range of unstable wavelengths. If the imposed field is time varying, parametric...

Net flow of electrolyte induced by a traveling-wave electric potential applied to an array of microelectrodes is reported. Two fluid flow regimes have been observed: at small-voltage amplitudes the fluid flow follows the direction of the traveling wave, and at higher-voltage amplitudes the fluid flow is reversed. In both cases, the flow seems...

We have investigated the onset of avalanches in fine, cohesive granular materials. In our experiments shear stress is generated by tilting an initialized bed of powder and increasing the angle of tilt until the powder avalanches. We find that the angle a of the avalanche decreases with increasing bed width. The avalanche depth increases with...