Abstract:
THE PORTABLE THERMAL CONDUCTIVITY PROBE WAS DEVELOPED IN TORONTO BY UTILIZING A TRANSIENT HEAT-FLOW PRINCIPLE. THE TESTS ARE ACCOMPLISHED IN A FEW MINUTES, BEFORE THE MOISTURE MIGRATION CAN SIGNIFICANTLY DISTURB THE ORIGINAL DISTRIBUTION, WHILE AT THE SAME TIME THIS MECHANISM IS INCLUDED AS A CONTRIBUTING FACTOR IN THE MEASURED PROPERTIES. THE PROBE IS DESCRIBED AND CONSISTS OF AN ALUMINUM TUBE APPROXIMATELY 18 IN. IN LENGTH. INSIDE OF THE TUBE IS STRETCHED AN AXIAL CONSTANTAN RESISTANCE WIRE WHICH SERVES AS A CONSTANT STRENGTH HEAT SOURCE. NEAR THE CENTER OF THE TUBE LENGTH IN CONTACT WITH THE INNER WALL ARE THE HOT JUNCTIONS OF SEVERAL THERMOCOUPLES ARRANGED IN SERIES WITH EXTERNAL COLD JUNCTIONS. THE TUBE IS CLOSED BY A STEEL TIP AT THE LOWER END AND THE WIRING CARRIED OUT THROUGH A SEAL AT THE UPPER END. THE NECESSARY POTENTIOMETER, BATTERY AND CONTROLS ARE CONVENIENTLY MOUNTED IN A SUITCASE TO MAKE THE EQUIPMENT PORTABLE. TO MAKE A DETERMINATION, THE PROBE IS THRUST INTO THE SOIL FOR ITS FULL LENGTH. EQUATIONS ARE PRESENTED WHICH ARE USED TO DETERMINE THE THERMAL CONDUCTIVITY DIRECTLY FROM THE OBSERVATIONS OBTAINED. THE PROBE IS NOT YET COMMERCIALLY AVAILABLE.
Supplemental Notes:
pp 57-59, 3 FIG, 3 REF. Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved.
