DoRN-effect

The streaming potential (Dorn effect) relates to a movement of liquid that generates electric potential, and electroosmosis occurs when a direct electric potential causes movement of the liquid. The sedimentation potential relates to sedimentation (directed movement) of charged particles that generates electric potential, and electrophoresis occurs when a direct electric potential causes a movement of charged particles. 

Dorn effect phys chem A difference In a potential resulting from the motions of particles through water the potential exists between the particles and the water. ( dorn l,fekt ... 

Dorn effect Dorn potential, and - sedimentation potential... 

The colloid vibration potential (difference) E or CVP is the a.c. potential difference measured between two Identical relaxed electrodes, placed in the dispersion if the latter Is subjected to an (ultra)sonlc field. CVP Is a particular case of the more general phenomenon, ultrasonic vibration potential (UVP), applying to any system, whether or not colloids are present. This field sets the particles into a vibrating motion, as a result of which the centres of particle charge and countercharge are periodically displaced with respect to each other. This phenomenon is the a.c. equivalent of that observed in the Dorn effect. Counterpart to this is the electrokinetic sonic amplitude, ESA, the amplitude of the (ultra)sonlc field created by an a.c, electric field in a dispersion. 

Use of the Dorn Effect to Check the Incomplete Retardation of a Buoyant Bubble Surface... 

A noticeable deviation of sedimentation potentials from Smoluchowski s formula takes place at large siuface concentration variation along the bubble surface. Before considering experimental data, it has to be pointed out that the validity of Smoluchowski s formula for the description of the Dorn effect at large Peclet numbers applies only to solid spherical particles. In particular, the correctness of conclusions of some papers (Dukhin, 1964 Dukhin Buikov, 1965 Derjaguin Dukhin, 1967, 1971) is experimentally confirmed by Usui et al. (1980). Sedimentation potential for four sizes of glass balls appears to be the same. Since the radii of the particles under consideration are approximately 50, 150, 250, and 350 pm, the absence of any effect of Peclet and Reynolds numbers on the sedimentation potential could be demonstrated. 

Sedimentation Potential The potential difference at zero current caused by the sedimentation of dispersed species. This mechanism of potential difference generation is known as the Dorn effect accordingly, the sedimentation potential is sometimes referred to as the Dorn potential. The sedimentation may occur under gravitational or centrifugal fields. The potential difference per unit length in a sedimentation potential cell is the sedimentation field strength. 

The reverse of electrophoresis occurs when small particles are allowed to fall through a liquid under the influence of gravity. A difference of potential is observed between two electrodes placed at different levels, and its magnitude again depends on the magnitude of the zeta potential. This phenomenon is known as the sedimentation potential or as the Dorn effect, after the German physicist Friedrich Ernst Dorn (1848-1916), who discovered it in 1880. 

Dorn effect Electrolyte solution Suspended particles Cause Result... 

The Dorn effect It occurs when particles suspended in the electrolyte solution precipitate under the influence of gravity (or centrifugal force), and results in potential difference between the top and bottom of suspension. 

Sedimentation Potential (Dorn effect) In this case the particles are allowed to settle or rise through a fluid under the influence of gravity (or using a centrifugal force) - When the particles move they leave behind their ionic atmosphere and this creates a potential difference in the direction of motion which can be measured using electrodes and an electrometer. 

Electrophoresis - solid particles caused to move through a stationary liquid Sedimentation potential - potential produced by the free fall of particles through a liquid (the Dorn effect)... 

The Dorn effect is one of the electrokinetic effects (q.v.), and is the converse of electrophoresis (q.v.). Charged particles falling through a stationary liquid set up a potential difference in the liquid column, opposing the motion of the particles. 

Electrophoresis (q.v.) Electro-osmosis (q.v.) charged particles through liquid liquid past stationary solid Sedimentation potential or Dorn effect (q.v.) Streaming potential (q.v.)... 

The reverse effect of electrophoresis arises when small particles which are suspen ded m a liquid ate forced to move, say by gravitation or by an ultrasonic or a centrifugal Reid. Then an electric field is generated in the direction of the movement and a potential difference can be measured between two electrodes in the liquid, one at the top, the other at the bottom of the vessel This potential difference is called migration potential or potential of failing particles and the effect is indicated as the DoRN-effect The experiments are difficult and as yet only few results have been obtained... 

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