Dorn potential

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

Sedimentation potential— (also called electrophoretic or Dorn potential) Potential difference established during sedimentation (caused, e.g., by gravitation or centrifugation) of small charged particles (suspended in solution dispersion of solid particles or emulsion of immiscible liquid droplets). 

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. 

Dorn potential — Potential difference established during sedimentation of charged particles (see -> sedimentation potential). 

In 1861, Georg Hermann Quincke described a phenomenon that is the converse of electroosmosis When an electrolyte solution is forced through a porous diaphragm by means of an external hydrostatic pressure P (Fig. 31.1ft), a potential difference called the streaming potential arises between indicator electrodes placed on different sides of the diaphragm. Exactly in the same sense, in 1880, Friedrich Ernst Dorn described a phenomenon that is the converse of electrophoresis During... 

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 ... 

Concerning the above-mentioned critical quantities the authors have in fact established (i) that irrespective of stress level damage is apparently initiated at a critical creep strain ec of 3 to 3.5% (ii) that a notable deviation of creep data from the potential law starts just at this strain level and (iii) that although the strain rate dev/df is a function of stress, the minimum in the Sherby-Dorn plot also occurs (for the tubular specimens) at ec. The postulated changes in sample morphology at about the time when the strain values started to deviate from Findley s equation, were in fact seen by these and other authors [42,52], who detected in U PVC deformed micro-cavities later... 

Like ASLV, HIV has a multistep mechanism for activation of membrane fusion. However, low pH is not required for HIV entry, and the virus instead uses a series of distinct interactions with components of the target membrane (reviewed in Dorns and Trono, 2000). The first interaction is with the CD4 protein. This binding event enables a subsequent contact between the HIV SU subunit gpl20 and a molecule of the chemokine receptor family (reviewed in Choe et al, 1998). It is this second interaction with molecules termed coreceptors that activates the membrane fusion potential of the TM subunit gp41 (reviewed in Berger et al, 1999). 

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. 

Dorns M, Vanhulle G, Baelde Y, Coulie P, Dupont P, Rihoux JP. Lack of potentiation by cetirizine of alcohol-induced psychomotor disturbances. Eur J Clin Pharmacol 1988 34(6) 619-23. 

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. 

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, J.D., and Adams, L.D., "The Etch Rate of Portland Cement Clinkers as It Relates to Structure and Hydraulic Potential," Microscope, Vol. 31,1983, pp. 37-42. 

The method which exploits the natural rising velocity of bubbles, without any external electric field, is the so-called flotation potential method [7-16]. Indeed, the charge-raising bubbles create an electric current, which develops a measurable electric potential difference, A, between two sufficiently distant points (Dorn s effect). The relation between the potential of the bubbles and A is... 

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. 

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