Adhesion particle-wall interactions

When (/9a 3> particle-wall interaction leads to partial or total adhesion of particles on the SdFFF channel wall. 

There are a number of industrial and technological areas in which nanoscale adhesion is important. One of the earliest fields concerned with adhesion on this scale was colloid science. Colloid particles lie in the intermediate region between macro and nano, with dimensions typically of the order of hundreds of nanometers up to a few microns. This means that their true contact areas he well within the nano-domain and are influenced by interactions on this length scale. Adhesion between such particles is important, due to its influence on mineral separation processes and on the aggregation of powders, for example, on the walls of machinery or in the forming of medical tablets. In an extraterrestrial context, such... 

The interaction process between aqueous solutions of potassium stearate with calcium chloride, in tubular turbulent devices, provides a stoichiometric reaction leading to a reduction of the reaction mixture residence time in the device, which prevents particle deposition on the technological equipment walls, and consequently increases the run between repairs reduces the specific amount of metal per structure due to the small size of the reactor reduces the process power capacity due to the removal of the mechanical mixing devices from the flow sheet and produces a finely divided suspension of the adhesion reducing powder. 

Partial adhesion on the SdFFF channel wall was achieved by using monodisperse spherical particles of polymethyl methacrylate (PMMA) with nominal diameter 0.358 p.m." " The extent of the PMMA particles adhesion and detachment on and from the channel wall depends on the concentration of the indifferent electrolyte Ba(N03)2 added to the suspending medium to influence the total potential energy of interaction between the PMMA particles and the channel wall. When the concentration of the electrolyte exceeds a given value, which is called critical electrolyte concentration (CEC), total adhesion of the colloidal particles occurs at the beginning of the SdFFF channel wall. 

To characterize the gas flow in the fluidized bed, important forces are viscous and inertia as well as par-ticle-to-gas forces. For the particles, the important forces include gravity, particle inertia, gas interaction with the particles such as drag, collisional forces between particles and between particles and wall, and particle surface forces such as electrostatic and adhesion forces. For larger particles, in Geldart groups B or D, the particle surface forces can be neglected. The question is complicated for smaller particles because the surface forces are difficult to quantify. We must... 

Adhesion and agglomeration are vitally important in the gas-solid transport area although they have not received much attention in that respect. There have been numerous studies on these subjects relating the solid particles and surfaces to static conditions. As particles flow in a pipe, a certain number of the particles adhere to the soUd surface while others find their way into small crevices in the system. In the flow of a fine powder in a pipe, after the initial deposition of the particles to the pipe wall, the particles in suspension will interact with those adhering to the wall, causing different frictional and electrostatic behavior than would be anticipated from interactions of the particles with the pipe wall material alone, whether it is metal, plastic, or glass. 

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