Electro phenomenon

An innovative technology called the "lasagna" process is based on the electrokinetic phenomenon called electro osmosis. The lasagna process was created to treat difficult wastes in low permeabiUty, sdt- and clay-laden soils (40). The lasagna process is so named because it consists of a number of layered subsurface electrodes and treatment zones. These layers can be constmcted either horizontally where contaminants are forced to more upward or in vertical position where lateral contaminant movement is desired. 

Once a matrix of particles is formed, whether filter cake, thickened underflow, or soil, applying a current to the fluid causes a movement of ions in the water and, with the ions, water of hydration. The phenomenon is called electro osmosis. The pressure generated on the fluid is given by (127) ... 

Electro-osmosis has been defined in the literature in many indirect ways, but the simplest definition comes from the Oxford English Dictionary, which defines it as the effect of an external electric held on a system undergoing osmosis or reverse osmosis. Electro-osmosis is not a well-understood phenomenon, and this especially apphes to polar non-ionic solutions. Recent hterature and many standard text and reference books present a rather confused picture, and some imply directly or indirectly that it cannot take place in uniform electric fields [31-35]. This assumption is perhaps based on the fact that the interaction of an external electric held on a polar molecule can produce only a net torque, but no net force. This therefore appears to be an ideal problem for molecular simulation to address, and we will describe here how molecular simulation has helped to understand this phenomenon [26]. Electro-osmosis has many important applications in both the hfe and physical sciences, including processes as diverse as water desahnation, soil purification, and drug delivery. 

Usually, this phenomenon limits the lifetime of a battery because the storage capacity falls below a reasonable lower limit. One reason for this zinc migration was identified by McBreen [35] an inhomogeneous current distribution makes the zinc move away from high current density areas. Another mechanism seems to be active as well an electrolyte convection induced by electro-osmosis through the separator [36],... 

A disadvantage of methanol, however, is the phenomenon of electro-osmotic drag" in which protons moving through the... 

An LCD is a ubiquitous electronic display. Now, it is widely distributed among human daily life, like mobile phones, TV, and personal computers. The LCD has, however, a drawback, i.e., slower response than a plasma display or an electroluminescene display. Recently we have first succeeded in combination of a nanoparticle technology with the LCD technology, which realized fast response of the LCD [45,235,236]. Thus we have found a phenomenon, i.e., a frequency modulation of the LCD doped with metallic nanoparticles. Since the frequency modulation, or electro-optic property depends on the kind of metals, we have prepared AgPd bimetallic nanoparticles protected with a typical liquid crystal molecule, 4-cyano-4 -pentylbiphenyl (5CB) to investigate the electro-optic property [45,235,236]. 

When the direction of scan is reversed (according to the potential-time impulse of the type illustrated in Figure lb), the voltammetric curve resembles the trace CDE of Figure 2 because exactly the same phenomenon becomes established for the newly electro generated species... 

Schofield Phil. Mag. March, 1926) has recently verified this relation by direct experiment. In order to appreciate the significance of this result, it is necessary to consider in more detail the electrical potential difference V and the manner in which it arises. Instead of regarding the phenomenon from the point of view of the Gibbs equation, it has been, until recently, more usual to discuss the subject of electro-capillarity from the conceptions developed by Helmholtz and Lippmann. These views, together with the theory of electrolytic solution pressure advanced by Nemst, are not in reality incompatible with the principles of adsorption at interfaces as laid down by Gibbs. 

The ultrafiltration of the microemulsion is a very useful operation for separating water and oil in these mixtures [117-120]. Because of the limited availability of solvent stable membranes, most of the work pubHshed so far was performed using ceramic membranes, which show a high adsorption of surfactant at the membrane surface and comparably low rejection rates of reverse micelles. Using electro ultrafiltration, where the concentration polarisation phenomenon of the reverse micelles (using the ionic surfactant AOT) at the membrane surface is depressed by asymmetric high voltage electrical fields, the rejection rates can be increased,but not to economical values [121,122]. 

In fact, the phenomenon and conditions described here can be applied not only to a beam of electrons, but also to a beam of X-rays.12 What is the difference in the diffraction pattern when these different sources of radiation are applied to an ordered array of atoms X-rays penetrate deeply into the ctystal, and information between spacing of planes inside the crystal is obtained from the diffraction pattern. In contrast, the use of low-energy electrons as a source of incident radiation with energies in the range of 10 to 500 eV ensures that only atoms close to the surface (one or two planes) produce the diffraction pattern. Since this is the region in contact with a solution, the region where electrochemical processes occur, LEED is the technique used in electro-... 

Consider that a potential difference is applied across a glass capillary tube filled with an electrolytic solution (Fig. 6.134). What would one expect Of course, one would expect a current to flow through the capillary according to Ohm s law. In practice, however, a remarkable and unexpected phenomenon is observed. In addition to the current, the solution itself begins to flow—the phenomenon of electro-osmosis. Liquid flow is generally associated with the application of a pressure gradient, but in this case it appears that a potential difference is doing the job normally achieved by a pressure difference. 

This phenomenon of electro-osmosis can be treated in mathematical form. The fact is that the velocity of flow of electrolyte, v, depends not only on its usual driving... 

One can transcribe the phenomenon in the form of an equation following the same thinking as for electro-osmosis. One says A current density j results not only from an electric field but also from a pressure difference AP, and, for small X and AP,... 

A Prototypical Convective Electro-Diffusional Phenomenon—Electro-Osmotic Oscillations... 

Preliminaries. This entire chapter is devoted to one physical phenomenon—electro-osmotic (Teorell) oscillations. As opposed to phenomena discussed in previous chapters, electro-convection will be of importance here in its interaction with electro-diffusion. 

As the permeability of the membrane for ions of different charge signs largely varies, salt diffusion through a membrane is accompanied by the establishment of a membrane potential. These concentration or dialysis potentials play an important part in the study of membrane phenomena. With the above described model, the phenomenon of electro-endosmosis i.e. the transport of solvent across a membrane under the influence of an electric field, can easily be explained also. 

This is also an important phenomenon in electro dialysis, as it diminishes the quantity of treated water. The direction of water transport is, actually in most cases from the desalting cells to the concentration cells. 

Let us start by considering a liquid on a planar, charged surface. If we apply an electric field parallel to the surface the liquid begins to move (Fig. 5.12). This phenomenon is called electro-osmosis. Why does the liquid start to move The charged surface causes an increase in the concentration of counterions in the liquid close to the surface. This surplus of counterions is moved by the electric field towards the corresponding electrode. The counterions drag the surrounding liquid with them and the liquid starts to flow. 

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