HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Fuqua, B. D. Articles by Brown, D. A. Search for Related Content PubMed Articles by Fuqua, B. D. Articles by Brown, D. A. Agricola Articles by Fuqua, B. D. Articles by Brown, D. A.

Computer Procedure for Calculating Counter-Diffusion Coefficients¹

ABSTRACT

A procedure for computer calculation of counter-diffusion coefficients has been combined with the quick-freeze technique to measure counter-diffusion of ions. Two separate programs were employed to evaluate the counter-diffusion coefficients at 0.1-cm increments along the diffusion axis. Subroutines were available in the programs for plotting the ion distribution curve and the relationships of counter-diffusion coefficients versus diffusion distance and counter-diffusion coefficients versus relative concentration. Examples of Sr²⁺ diffusing against H⁺ and Na⁺ diffusing against H⁺ are presented to illustrate the potentialities for computer calculation and plotting of significant diffusion parameters. The diffusion coefficients of both Sr²⁺ and Na⁺ varied with changes in the ionic concentrations indicative of counter-diffusion processes. The counter-diffusion coefficients determined by the computer procedure were essentially the same as the values calculated by the graphical method. The computer procedure is an accurate and rapid method for calculating diffusion coefficients which are dependent on concentration and is adaptable to both single and multi-ion systems.

¹ Contribution from the Agron. Dep., Univ. of Arkansas, Fayetteville 72701. Support of this project was by a grant from the National Science Foundation (GA-11544-Brown) and is gratefully acknowledged.

² Former Graduate Research Assistant, Associate Professor of Mathematics, and Professor of Agronomy, respectively.

Received for publication January 1, 1973. Accepted for publication March 6, 1973.