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 HighWire Citing Articles via Google Scholar Google Scholar Articles by Jaynes, D. B. Articles by Rogowski, A. S. Search for Related Content PubMed Articles by Jaynes, D. B. Articles by Rogowski, A. S. Agricola Articles by Jaynes, D. B. Articles by Rogowski, A. S.

Applicability of Fick's Law to Gas Diffusion¹

ABSTRACT

The comparison of Fick's Law for the diffusion of gas i in a vapor to the equations based on the kinetic theory of gases shows that only for certain special conditions is the Fickian diffusion coefficient, D_Fi, independent of the mole fraction of i and the diffusional fluxes of the other gases. These conditions include the diffusion of a trace concentration of gas through a gas mixture of any composition, equimolar, counter-current diffusion in a binary gas mixture, and diffusion in a ternary mixture where one gas is stagnant. In an O₂, CO₂, N₂ atmosphere, variations in diffusion coefficient of at least 10% from the tracer values are possible with variations in the mole fractions of the gas or the relative magnitude of their fluxes. The temperature and pressure dependency of the diffusion coefficient must also be recognized.

¹ Contribution from the U.S. Department of Agriculture, Agricultural Research Service, in cooperation with the Pennsylvania Agric. Exp. Stn., The Pennsylvania State University, University Park, PA 16802.

² Soil Scientist, U.S. Water Conservation Laboratory, Phoenix (formerly Graduate Assistant, The Pennsylvania State Univ.); and Soil Scientist, Northeast Watershed Research Center, University Park, Pa.

Received for publication October 18, 1982. Accepted for publication January 19, 1983.

This article has been cited by other articles:

				P. Cannavo, F. Lafolie, B. Nicolardot, and P. Renault Modeling Seasonal Variations in Carbon Dioxide and Nitrous Oxide in the Vadose Zone Vadose Zone J., August 24, 2006; 5(3): 990 - 1004. [Abstract] [Full Text] [PDF]

				V. E. Turcu, S. B. Jones, and D. Or Continuous Soil Carbon Dioxide and Oxygen Measurements and Estimation of Gradient-Based Gaseous Flux Vadose Zone J., November 11, 2005; 4(4): 1161 - 1169. [Abstract] [Full Text] [PDF]

				M. L. Rockhold, R. R. Yarwood, M. R. Niemet, P. J. Bottomley, and J. S. Selker Experimental Observations and Numerical Modeling of Coupled Microbial and Transport Processes in Variably Saturated Sand Vadose Zone J., May 12, 2005; 4(2): 407 - 417. [Abstract] [Full Text] [PDF]

				M. L. Rockhold, R. R. Yarwood, and J. S. Selker Coupled Microbial and Transport Processes in Soils Vadose Zone J., May 1, 2004; 3(2): 368 - 383. [Abstract] [Full Text] [PDF]

				L.P.R. Bidel, P. Renault, L. Pages, and L.M. Riviere Mapping meristem respiration of Prunus persica (L.) Batsch seedlings: potential respiration of the meristems, O2 diffusional constraints and combined effects on root growth J. Exp. Bot., April 1, 2000; 51(345): 755 - 768. [Abstract] [Full Text] [PDF]