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Diffusion of coefficients of carbon dioxide, nitrous oxide, ethylene and ethane in air and their measurement
Author(s) -
PRITCHARD D. T.,
CURRIE J. A.
Publication year - 1982
Publication title -
journal of soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.244
H-Index - 111
eISSN - 1365-2389
pISSN - 0022-4588
DOI - 10.1111/j.1365-2389.1982.tb01757.x
Subject(s) - carbon dioxide , nitrous oxide , diffusion , chemistry , gaseous diffusion , volumetric flow rate , volume (thermodynamics) , ethylene oxide , thermodynamics , analytical chemistry (journal) , steady state (chemistry) , ethylene , molecular diffusion , chromatography , physics , organic chemistry , electrode , copolymer , catalysis , polymer , metric (unit) , biochemistry , operations management , economics
Summary Binary diffusion coefficients were measured by a steady‐state method in which a gas was introduced at a constant rate into one end of a tube through which it moved by mass flow and diffusion into a semi‐infinite volume of air. The Stefan correction for mass flow was modified to allow for initial gas concentrations < 100 per cent, conferring four advantages: errors in the total flow rate are relatively unimportant; density gradients are small so that convection is inhibited; the gas analysis is more sensitive; and diffusion coefficients are measured at the small concentrations that are encountered in soils. Measured diffusion coefficients (cm 2 s −1 at NTP) in air for carbon dioxide (0.139), nitrous oxide (0.143), ethylene (0.137) and ethane (0.128) are compared with measured and calculated values from other sources.