The two distributions contain the same information, but the curve for the differentiated step is more easily obtained. The
situation for non-linear distributions is more complicated, but again the differential curve is generally more useful.
In summary, the method of moments when applied to the reverse-flow technique allows for a non-intrusive and accurate method
to determine the quality of flow distribution. This is particularly useful for preparatory or commercial columns, where column
packing is a tedious and expensive task. The use of statistical moments to evaluate column performance can provide a great
deal of information on column performance with little effort.
Anurag Rathore is a principal scientist at Amgen Inc., 30W-2-A, One Amgen Center Drive, Thousand Oaks, CA 91320, 805.447.4491, fax 805.499.5008,
John Moscariello is a scientist at Amgen Inc., Seattle, WA.
Edwin Lightfoot is a professor at Department of Chemical and Biological Engineering, University of Wisconsin, Madison.
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