基礎講座 電気泳動(Electrophoresis)

1: Magnetic Particles: Preparation, Properties and Applications: M. Ozaki. 2: Maghemite (gamma-Fe2O3): A Versatile Magnetic Colloidal Material C.J. Serna, M.P. Morales. 3: Dynamics of Adsorption and Oxidation of Organic Molecules on Illuminated Titanium Dioxide Particles Immersed in Water M.A. Blesa, R.J. Candal, S.A. Bilmes. 4: Colloidal Aggregation in Two-Dimensions A. Moncho-Jorda, F. Martinez-Lopez, M.A. Cabrerizo-Vilchez, R. Hidalgo Alvarez, M. Quesada-PMerez. 5: Kinetics of Particle and Protein Adsorption Z. Adamczyk.

Surface and Colloid Science

Discrete particle simulation of particulate systems: Theoretical developments

An immersed boundary method with direct forcing for the simulation of particulate flows

We present a multi–purpose CFD–DEM framework to simulate coupled fluid–granular systems. The motion of the particles is resolved by means of the Discrete Element Method (DEM), and the Computational Fluid Dynamics (CFD) method is used to calculate the interstitial fluid flow. We first give a short overview over the DEM and CFD–DEM codes and implementations, followed by elaborating on the numerical schemes and implementation of the CFD–DEM coupling approach, which comprises two fundamentally different approaches, the unresolved CFD–DEM and the resolved CFD–DEM using an Immersed Boundary (IB) method. Both the DEM and the CFD–DEM approach are successfully tested against analytics as well as experimental data.

Models, algorithms and validation for opensource DEM and CFD-DEM

An optical method to deterministically manipulate nanosized particles in suspensions within confined microfluidic devices is introduced. We show that under appropriate conditions strong dielectrophoretic forces several orders of magnitude larger than the Brownian force can be generated using an external optical actuation. A self-consistent coupled point-dipole model that includes the redistribution of charges on the channel boundaries allows us to specify the underlying mechanisms and estimate the optical forces experienced by a nanoparticle.

Optical manipulation of neutral nanoparticles suspended in a microfluidic channel

Using resonances to control chaotic mixing within a translating and rotating droplet

Autoregressive methods for chaos on binary sequences for the Lorenz attractor

The aim of this paper is to study the mechanism by which clumps of some powdered materials break up and disperse on a liquid surface to form a monolayer of particles. We show that a clump breaks up because when particles on its outer periphery come in contact with the liquid surface they are pulled into the interface by the vertical component of capillary force overcoming the cohesive forces which keep them attached, and then these particles move away from the clump. In some cases, the clump itself is broken into smaller pieces and then these smaller pieces break apart by the aforementioned mechanism. The newly-adsorbed particles move away from the clump, and each other, because when particles are adsorbed on a liquid surface they cause a flow on the interface away from themselves. This flow may also cause particles newly-exposed on the outer periphery of the clump to break away. Interestingly, when many particles asymmetrically break away from a clump, the clump itself is pushed in the opposite direction by the flow caused by the newly-adsorbed particles. Since millimeter-sized clumps can breakup and spread on a liquid surface within a few seconds, their behavior appears to be similar to that of some liquid drops which can spontaneously spread on solid surfaces. However, if the capillary force is not large enough to overcome the cohesive force holding the clump together, the clump may not breakup.

Breakup of particle clumps on liquid surfaces

/pdf/particles-dispersion-on-fluid-liquid-interfaces-387xs6gr9d.pdf

Pushpendra Singh

Papers

Optical manipulation of neutral nanoparticles suspended in a microfluidic channel

Using resonances to control chaotic mixing within a translating and rotating droplet

Autoregressive methods for chaos on binary sequences for the Lorenz attractor

Breakup of particle clumps on liquid surfaces

Particles Dispersion on Fluid-Liquid Interfaces