Correlation of solute permeability and reflection coefficient for rigid membranes with high solvent content

1972 ◽  
Vol 76 (3) ◽  
pp. 393-399 ◽  
Author(s):  
Gerald S. Manning
Keyword(s):  
Reflection Coefficient ◽  
Solvent Content ◽  
Solute Permeability

scholarly journals Implementation of Spiegler–Kedem and Steric Hindrance Pore Models for Analyzing Nanofiltration Membrane Performance for Smart Water Production

Membranes ◽  
2018 ◽  
Vol 8 (3) ◽  
pp. 78 ◽  
Author(s):  
Remya Nair ◽  
Evgenia Protasova ◽  
Skule Strand ◽  
Torleiv Bilstad
Keyword(s):  
Mass Transfer ◽  
Reflection Coefficient ◽  
Oil Recovery ◽  
Water Permeability ◽  
Structural Parameters ◽  
Pure Water ◽  
Model Parameters ◽  
Water Production ◽  
Solute Permeability ◽  
Smart Water

A predictive model correlating the parameters in the mass transfer-based model Spiegler–Kedem to the pure water permeability is presented in this research, which helps to select porous polyamide membranes for enhanced oil recovery (EOR) applications. Using the experimentally obtained values of flux and rejection, the reflection coefficient σ and solute permeability Ps have been estimated as the mass transfer-based model parameters for individual ions in seawater. The reflection coefficient and solute permeability determined were correlated with the pure water permeability of a membrane, which is related to the structural parameters of a membrane. The novelty of this research is the development of a model that consolidates the various complex mechanisms in the mass transfer of ions through the membrane to an empirical correlation for a given feed concentration and membrane type. These correlations were later used to predict ion rejections of any polyamide membrane with a known pure water permeability and flux with seawater as a feed that aids in the selection of suitable nanofiltration (NF) for smart water production.

Differential action of plasma and albumin on transcapillary exchange of anionic solute

1993 ◽  
Vol 264 (5) ◽  
pp. H1428-H1437 ◽  
Author(s):  
V. H. Huxley ◽  
F. E. Curry ◽  
M. R. Powers ◽  
B. Thipakorn
Keyword(s):  
Reflection Coefficient ◽  
Permeability Coefficient ◽  
Protein Composition ◽  
Solvent Drag ◽  
Solute Permeability ◽  
Charge Selectivity ◽  
Microvessel Wall ◽  
Solute Permeability Coefficient ◽  
Differential Action ◽  
Alpha Lactalbumin

We tested two hypotheses to account for the reduction in coupling of anionic solute to water flow (solvent drag) in microvessels during perfusion with plasma compared with albumin. Solvent drag is determined by both hydraulic conductivity (Lp) and solute reflection coefficient (sigma). Accordingly, decreased solvent drag during plasma perfusion must be the result of an increase in sigma (hypothesis 1) or reduction of Lp (hypothesis 2) or some combination of both mechanisms. These hypotheses were assessed by measuring Lp, sigma, and diffusive solute permeability (Psd) to the anionic protein alpha-lactalbumin in frog mesenteric exchange microvessels during plasma or albumin perfusion. The solute permeability coefficient to alpha-lactalbumin (Ps alpha-lactalbumin) was lower during exposure to plasma than bovine serum albumin (BSA) [(Ps alpha-lactalbumin)plasma/(Ps alpha-lactalbumin)BSA = 0.31 +/- 0.11 (means +/- SE, n = 9)]. Solute reflection coefficient to alpha-lactalbumin (sigma alpha-lactalbumin) was 0.69 +/- 0.02 in plasma and 0.34 +/- 0.03 in BSA (n = 7). Lp was not significantly influenced by perfusate protein composition (Lp plasma/Lp BSA = 1.02 +/- 0.11; n = 20). These data lead to the conclusion that the actions of plasma are to confer charge selectivity for anionic solute and, to a lesser extent, modify the porous pathways of the microvessel wall. Taken together, these results indicate that porous pathways contribute significantly to macromolecular flux in plasma-perfused vessels.

scholarly journals A Physical Interpretation of the Phenomenological Coefficients of Membrane Permeability

1961 ◽  
Vol 45 (1) ◽  
pp. 143-179 ◽  
Author(s):  
O. Kedem ◽  
A. Katchalsky
Keyword(s):  
Reflection Coefficient ◽  
Physical Interpretation ◽  
Electrical Current ◽  
Distribution Coefficients ◽  
Ion Concentration ◽  
Solute Permeability ◽  
Reference Curves ◽  
Phenomenological Coefficients ◽  
Charged Membranes ◽  
Solute Permeability Coefficient

A "translation" of the phenomenological permeability coefficients into friction and distribution coefficients amenable to physical interpretation is presented. Expressions are obtained for the solute permeability coefficient ω and the reflection coefficient σ for both non-electrolytic and electrolytic permeants. An analysis of the coefficients is given for loose membranes as well as for dense natural membranes where transport may go through capillaries or by solution in the lipoid parts of the membrane. Water diffusion and filtration and the relation between these and capillary pore radius of the membrane are discussed. For the permeation of ions through the charged membranes equations are developed for the case of zero electrical current in the membrane. The correlation of σ with ω and Lp for electrolytes resembles that for non-electrolytes. In this case ω and σ depend markedly on ion concentration and on the charge density of the membrane. The reflection coefficient may assume negative values indicating anomalous osmosis. An analysis of the phenomena of anomalous osmosis was carried out for the model of Teorell and Meyer and Sievers and the results agree with the experimental data of Loeb and of Grim and Sollner. A set of equations and reference curves are presented for the evaluation of ω and σ in the transport of polyvalent ions through charged membranes.

Transport by epithelia with compliant lateral intercellular spaces: asymmetric oncotic effects across the rat proximal tubule

1984 ◽  
Vol 247 (5) ◽  
pp. F848-F862 ◽  
Author(s):  
A. M. Weinstein
Keyword(s):  
Reflection Coefficient ◽  
Proximal Tubule ◽  
Electrical Resistance ◽  
Volume Flow ◽  
Intercellular Spaces ◽  
Water Reabsorption ◽  
Solute Permeability ◽  
Lateral Intercellular Spaces ◽  
Rat Proximal Tubule

Mathematical models of the proximal tubule are considered in which the lateral intercellular spaces distend in response to increased interstitial pressures and basal outlet permeabilities increase as a result of interspace widening. An approximate analytical model of the interspace reveals the possibility that such compliance may introduce an asymmetry to the effect of protein oncotic forces on transepithelial volume flow. Peritubular oncotic forces close the interspace, enhance interspace hypertonicity, and thus substantially increase volume reabsorption (enhanced intraepithelial solute-solvent coupling). The model also predicts a decline in epithelial water permeability (Lp), salt reflection coefficient, and salt permeability, with the application of peritubular protein. When parameters are chosen so as to represent the rat proximal tubule, the predicted effect on solute permeability is comparable to the observed changes in electrical resistance of the epithelium. However, when the luminal solution is slightly hypotonic to blood and proximal reabsorption has become isosmotic, the models show relatively small protein effects, which are dependent upon cell and tight junction permeabilities and are little influenced by interspace compliance. The capability of such models to represent the peritubular protein enhancement of isosmotic salt and water reabsorption by the proximal tubule in vivo is questioned.

The method of determining the metrological performance of unit reference standards of reflection coefficient in waveguides at millimeter waves

2020 ◽  
pp. 59-63
Author(s):  
A.S. Bondarenko ◽  
A.S. Borovkov ◽  
I.M. Malay ◽  
V.A. Semyonov
Keyword(s):  
Reflection Coefficient ◽  
Millimeter Waves ◽  
Primary Standard ◽  
Reference Standards ◽  
Measurement Scale ◽  
Current State ◽  
Coefficient Measurement ◽  
Mathematical Equations ◽  
Electrodynamic Modeling ◽  
Metrological Performance

The analysis of the current state of the reflection coefficient measurements in waveguides at millimeter waves is carried out. An approach for solving the problem of reproducing the reflection coefficient measurement scale is proposed. Mathematical equations, which are the basis of the reflection coefficient measurement equation are obtained. The method of determining the metrological performance of reflection coefficient unit’s reference standards is developed. The results of electrodynamic modeling and analytical calculations by the developed method are compared. It is shown that this method can be used for reproducing the reflection coefficient unit in the development of the State primary standard.

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