Bistability and electrokinetic oscillations

Rastogi, R. P. ; Mishra, G. P. ; Pandey, P. C. ; Bala, Kanchan ; Kumar, K. (1999) Bistability and electrokinetic oscillations Journal of Colloid and Interface Science, 217 (2). pp. 275-287. ISSN 0021-9797

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Official URL: http://linkinghub.elsevier.com/retrieve/pii/S00219...

Related URL: http://dx.doi.org/10.1006/jcis.1999.6302

Abstract

Nonlinear dynamic behavior and electrokinetic oscillations have been investigated for the membrane systems (a) 0.1 N NaCl/KClMillipore filter 0.01 N NaCl/KCl; (b) 0.1 N NaCl/KCl Whatman Inorganic filter 0.01 N NaCl/KCl; and (c) 0.1 N NaCl/KCl silver-coated filter 0.01 N NaCl/KCl, from the viewpoint of testing the theories for the phenomena and elucidating the mechanism. To achieve these objectives, studies on hydrodynamic permeability, electroosmotic permeability, bistability, and electrokinetic oscillations were undertaken. Relaxation time for buildup and decay of electroosmotic pressures was experimentally determined. Bistability was not observed showing that it is not a prerequisite for oscillations and nonlinear relations between (Jv)Δρ=0 and Δφ involving cubic or higher-order terms are necessary for bistability. The oscillations were studied at different current strengths. The period is found to be independent of current, while amplitude A is found to be linearly related to current I which is the bifurcation parameter. The bifurcation point occurs at not, vert, similar0.4 mA. Studies have also been made with membranes of different pore size that show that amplitude increases with increase in pore size of the membranes. The validity of the two-variable model of Teorell was examined by comparing the experimental results with computer simulation based on parameters determined experimentally. Theory does not meet expectation and the results suggest that modification of theory is needed. The weakness of the theory has been critically examined.

Item Type:Article
Source:Copyright of this article belongs to Elsevier Science.
Keywords:Bistability; Oscillations; Electrokinetic Phenomena; Membrane Processes
ID Code:44383
Deposited On:21 Jun 2011 13:14
Last Modified:22 Jun 2011 07:06

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