<?xml version='1.0' encoding='utf-8'?>
<oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd">
  <dc:contributor>Karen A. Mello</dc:contributor>
  <dc:creator>John R. Nimmo</dc:creator>
  <dc:date>1991</dc:date>
  <dc:description>&lt;p&gt;&lt;span&gt;Centrifugal force is an alternative to large pressure gradients for the measurement of low values of saturated hydraulic conductivity (&lt;/span&gt;&lt;i&gt;K&lt;/i&gt;&lt;sub&gt;sat&lt;/sub&gt;&lt;span&gt;). With a head of water above a porous medium in a centrifuge bucket, both constant-head and falling-head measurements are practical at forces up to at least 1800 times normal gravity. Darcy's law applied to the known centrifugal potential leads to simple formulas for&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;/span&gt;&lt;i&gt;K&lt;/i&gt;&lt;sub&gt;sat&lt;/sub&gt;&lt;span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;that are analogous to those used in the standard gravity-driven constant- and falling-head methods. Both centrifugal methods were tested on several fine-textured samples of soil and ceramic with&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;/span&gt;&lt;i&gt;K&lt;/i&gt;&lt;sub&gt;sat&lt;/sub&gt;&lt;span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;between about 10&lt;/span&gt;&lt;sup&gt;−10&lt;/sup&gt;&lt;span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;and 10&lt;/span&gt;&lt;sup&gt;−9&lt;/sup&gt;&lt;span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;m/s. The results were compared to falling-head gravity measurements. The comparison shows most measurements agreeing to within 20% for a given sample, much of the variation probably resulting from run-to-run changes in sample structure. The falling-head centrifuge method proved to be especially simple in design and operation and was more accurate than the constant-head method. With modified apparatus,&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;/span&gt;&lt;i&gt;K&lt;/i&gt;&lt;sub&gt;sat&lt;/sub&gt;&lt;span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;measurements less than 10&lt;/span&gt;&lt;sup&gt;−10&lt;/sup&gt;&lt;span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;m/s should be attainable.&lt;/span&gt;&lt;/p&gt;</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>10.1029/91WR00367</dc:identifier>
  <dc:language>en</dc:language>
  <dc:publisher>American Geophysical Union</dc:publisher>
  <dc:title>Centrifugal techniques for measuring saturated hydraulic conductivity</dc:title>
  <dc:type>article</dc:type>
</oai_dc:dc>