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7-i4-04; i7:40 ;Lester Buliding ;3203955376 # t0/ 28 <br /> Article Request Page Page 8 of 26 <br /> � <br /> (! <br /> Figure 6.Zachary Hartjes applying water to tank S.Data acquisition system for ECHO probes <br /> shown in foreground. <br /> Moisture Meters <br /> Dielectric conatants for the sand in tanks 2,4 and 6 were continuously monitored using ECH 2 O <br /> Diel�tric Aquameters(a.k.a.ECHO probes)and a Campbell Scientific CR23X datalogger.Via a <br /> calibration process described later,probe output was related to the sand's volumetric moisture <br /> content.Probes were placed in the tanks horizontally with the flat side perpendicular to the soil <br /> surface as shown in figure 3b.Probes were positioned at depths of 7,21, 35 and 49 cm below the <br /> sand surface.These deptlis correspond t�the elevations of the top and bottom surfaces of the <br /> footings(figure 1).Because we only had 11 probes,we did not place a probe at the 49 cm depth in <br /> tank 6. <br /> Footing Removal and Testing <br /> A top,middle,and bottom footing were removed from each of the six tanks after being subjected to <br /> the previously descnbed water treatrnents for 4 weeks.These footings were all removed from the <br /> same end of each tank.Eight weeks later(twelve weeks from beginning of water treatments)a <br /> second set of footings were removed from the opposite end of the tanks from where the first <br /> footings were removed.The rcmaining footings(located in the middle of each tank)and all ECHO <br /> probea were removed twelve weeks after removal of the second 8et of footings or 24 weeks after <br /> commencement of water treatments. <br /> As footings were excavated,sand at ECHO pmbe depths of 7,21,35 and 49 cm was removed from <br /> each tank,and its moisture content determined in accordance with ASTM D4959-00.Immediately <br /> after all three footings were removed from the end of a tank,excavated sand was replaced and <br /> compacted into the tank so as not to significantly affect moisture conditions suimunding those <br /> footings still in the tank.Additional sand was added at this time to compensate for volume lost due <br /> http://asae.fiymulti.com/requestZ.asp?JII�S&AID=14082&CID=1nv2003&v=8�i=&T=1 6/4/2004 <br />