General Physiology and Biophysics Vol.30, No.2, p.186–195, 2011
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Title: Estimation of thickness of concentration boundary layers by osmotic volume flux determination |
Author: Jolanta S. Jasik-Ślęzak, Kornelia M. Olszówka, Andrzej Ślęzak |
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Abstract: The estimation method of the concentration boundary layers thicknesses (δ) in a single-membrane system containing non-electrolytic binary or ternary solutions was devised using the Kedem-Katchalsky formalism. A square equation used in this method contains membrane transport (Lp, σ, ω) and solution (D, C) parameters as well as a volume osmotic flux (Jv). These values can be determined in a series of independent experiments. Calculated values δ are nonlinearly dependent on the concentrations of investigated solutions and the membrane system configuration. These nonlinearities are the effect of a competition between spontaneously occurring diffusion and natural convection. The mathematical model based on Kedem-Katchalsky equations and a concentration Rayleigh number (RC) was presented. On the basis of this model we introduce the dimensionless parameter, called by us a Katchalsky number (Ka), modifies RC of membrane transport. The critical value of this number well describes a moment of transition from the state of diffusion into convective diffusion membrane transport.
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Keywords: Membrane transport — Kedem-Katchalsky equations — Concentration boundary layers — Volume flux — Katchalsky number |
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Year: 2011, Volume: 30, Issue: 2 |
Page From: 186, Page To: 195 |
doi:10.4149/gpb_2011_02_186
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