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    <title>Transport Research International Documentation (TRID)</title>
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    <copyright>Copyright © 2026. National Academy of Sciences. All rights reserved.</copyright>
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    <managingEditor>tris-trb@nas.edu (Bill McLeod)</managingEditor>
    <webMaster>tris-trb@nas.edu (Bill McLeod)</webMaster>
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      <title>Transport Research International Documentation (TRID)</title>
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      <link>https://trid.trb.org/</link>
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    <item>
      <title>ANALYSIS AND IMPROVED DESIGN OF GAMMA-RAY BACKSCATTERING DENSITY GAGES</title>
      <link>https://trid.trb.org/View/110054</link>
      <description><![CDATA[THE NUCLEAR REACTIONS WHICH GAMMA RADIATION MAY UNDERGO IN A MATERIAL OF MEDIUM ATOMIC WEIGHT, SUCH AS SOIL, ARE DISCUSSED AND RELATED TO THE PROPERTIES OF BACKSCATTERING DENSITY GAGES. THEORETICAL REASONING AND EXPERIMENTAL EVIDENCE ARE PRESENTED TO SHOW THAT THE EFFECT OF THE CHEMICAL COMPOSITION OF THE MATERIAL MAY BE ELIMINATED WHEN' /A/ THE DETECTOR SEES MATERIAL NEAR THE SOURCE, AND /B/ PHOTONS OF ENERGY BELOW 0.1 MEV ARE NOT DETECTED. THE LATTER MAY BE ACHIEVED WITH A SCINTILLATION COUNTER AND PULSE SELECTOR OR BY PLACING IRON FILTERS IN FRONT OF A GEIGER-MULLER TUBE. THE GEOMETRY DEFINED BY /A/ CAUSES THE PEAK IN THE CALIBRATION CURVE TO MOVE TO A DENSITY SO HIGH THAT THE COUNT RATE BECOMES A UNIQUE MEASURE OF DENSITY, RISING OVER THE ENTIRE RANGE OF DENSITY FROM 0 TO 160 PCF. ERRORS IN THE DENSITY READING DUE TO THE STATISTICS OF NUCLEAR COUNTING AND SURFACE ROUGHNESS ARE DISCUSSED. /AUTHOR/]]></description>
      <pubDate>Fri, 18 Nov 1994 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/110054</guid>
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    <item>
      <title>QUANTITATIVE FABRIC OF WET KAOLINITE</title>
      <link>https://trid.trb.org/View/127984</link>
      <description><![CDATA[A METHOD IS DESCRIBED FOR QUANTITATIVELY EXPRESSING ORIENTATION OF KAOLINITE PARTICLES IN A WET CLAY MASS. WET CLAY IS IMPREGNATED WITH A POLYALCOHOL WHICH PERMITS GRINDING OF A VERY FLAT SURFACE /WITHOUT DISRUPTING THE ORIGINAL FABRIC/ FOR QUANTITATIVE X-RAY MEASUREMENT. IN THE SPECIFIC PROCEDURE DISCUSSED, A NORELCO DIFFRACTOMETER EQUIPPED WITH A POLE FIGURE DEVICE AND A GEIGER DETECTOR WAS EMPLOYED TO MEASURE BY REFLECTION THE DIFFRACTED INTENSITY OF THE 002 AND 020 KAOLINITE REFLECTIONS. THE AMPLITUDE OF THE 002 PEAK TO THE AMPLITUDE OF THE 020 PEAK IS CALLED THE PEAK RATIO, PR, WHICH QUANTITATIVELY EXPRESSES PARTICLE ORIENTATION AT ANY CHOSEN ANGLE TO THE SPECIMEN SURFACE. LIMITS OF ORIENTATION ARE RANDOM AND MAXIMUM ORIENTATION. FOR THE KAOLINITE TESTED, TRULY RANDOM ORIENTATION WAS ACHIEVED WHICH GAVE A PR EQUAL 2. MAXIMUM ORIENTATION FOUND EXPERIMENTALLY WAS PR EQUAL 200 FOR THOROUGHLY DISPERSED SLURRY SLOWLY DRIED ON A GLASS SLIDE. VERTICAL AND LATERAL VARIATIONS CAN BE MEASURED EITHER CONTINUOUSLY OR IN STEPS OF ANY CHOSEN SIZE. /AUTHOR/]]></description>
      <pubDate>Thu, 11 Aug 1994 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/127984</guid>
    </item>
    <item>
      <title>RATES AND MECHANISMS OF HYDRATION OF CLINKER MINERALS IN PASTE FORM</title>
      <link>https://trid.trb.org/View/101525</link>
      <description><![CDATA[ALL THE USUAL METHODS OF DETERMINING THE RATE OF HYDRATION OF CLINKER MINERALS, IN WHICH THE PROGRESS OF HYDRATION IS DETERMINED IN DRIED AND PULVERIZED SAMPLES ARE, STRICTLY SPEAKING, INDIRECT METHODS. THE HYDRATION MECHANISM CAN BE ELUCIDATED ONLY BY EXAMINING THE REACTION IN THE ACTUAL PASTE CONSISTING OF THE RELEVANT MINERAL AND WATER. IN THE PRESENT INVESTIGATIONS, PURE SPECIMENS OF TRICALCIUM ALUMINATE, TETRACALCIUM ALUMINATE FERRITE, TRICALCIUM SULFATE, ALITE, AND BETA-DICALCIUM SULFATE WERE STUDIED. THE PASTE MIXED WITH WATER IS PUT INTO A SPECIMEN-HOLDER SEALED WITH PLASTIC SHEET, AND THE REDUCTION OF THE STRONGEST X-RAY REFLECTION OF THE INITIAL SUBSTANCE IS CHECKED WITH THE AID OF A GEIGER COUNTER. THE FIRST OBSERVATION CAN BE MADE 6 MINUTES AFTER THE SUBSTANCE IS BROUGHT INTO CONTACT WITH WATER. THE HYDRATION RATES OF THE SUBSTANCES EXAMINED VARY EXCEEDINGLY BUT, IN ALL OF THEM, TWO STAGES OF THE REACTION ARE CLEARLY DISTINGUISHABLE: THE SURFACE REACTION, IN WHICH THE WATER PENETRATES INTO THE INTERIOR OF THE GRAINS AT A CONSTANT RATE, AND THE DIFFUSION REACTION, IN WHICH THE DIFFUSION OF THE WATER THROUGH THE REACTION LAYER THAT HAS FORMED BECOMES THE FACTOR WHICH DETERMINES THE RATE. THE TRANSITION FROM THE SURFACE REACTION TO THE DIFFUSION REACTION OCCURS AFTER 11 MINUTES IN THE CASE OF TRICALCIUM ALUMINATE, AND AFTER 18 DAYS IN THE CASE OF BETA-DICALCIUM SULFATE. /AUTHOR/]]></description>
      <pubDate>Tue, 01 Sep 1970 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/101525</guid>
    </item>
    <item>
      <title>MINIMIZING ERRORS IN GAMMA-RAY SURFACE TYPE DENSITY GAGES: EXISTING GAGES AND NEW DESIGN CONCEPTS</title>
      <link>https://trid.trb.org/View/110333</link>
      <description><![CDATA[BACKSCATTER-TYPE NUCLEAR DENSITY GAGES HAVE BEEN IN EXISTENCE FOR  MANY YEARS. THEY HAVE BEEN SLOW IN GAINING WIDESPREAD COMMERCIAL ACCEPTANCE BECAUSE THE QUESTION OF THEIR ACCURACY HAS NOT BEEN SATISFACTORILY RESOLVED. THE ERRORS IS REVIEWED, AND SUGGESTIONS FOR IMPROVING GAGE ACCURACY ON PRESENT-GENERATION COMMERCIAL GAGES ARE INCLUDED. THE DUAL-GAGE PRINCIPLE OFFERS MUCH PROMISE FOR THE IMPROVEMENT OF THE PERFORMANCE OF THESE GAGES. OPTIMUM DUAL-GAGE SYSTEMS ARE BEING DESIGNED ON THE BASIS OF MAXIMIZING A QUALITY FACTOR THAT IS A FUNCTION OF ALL THE GAGE ERRORS AND THE MEASUREMENT VOLUME. TWO PROTOTYPE GAGES HAVE BEEN CONSTRUCTED TO AID IN THIS EVALUATION: ONE USING GEIGER-MULLER-TYPE DETECTORS, AND THE OTHER A SODIUM IODIDE CRYSTAL DETECTOR. RESULTS FROM INITIAL TESTING OF BOTH OF THESE SYSTEMS ARE PRESENTED AND INDICATE THAT A SIGNIFICANT IMPROVEMENT IN ACCURACY IS POSSIBLE. /AUTHOR/]]></description>
      <pubDate>Mon, 03 Aug 1970 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/110333</guid>
    </item>
    <item>
      <title>PREPARATION OF SAMPLES FOR THE GEIGER COUNTER DIFFRACTOMETER</title>
      <link>https://trid.trb.org/View/102037</link>
      <description><![CDATA[THE SAMPLE IS GROUND UNTIL FURTHER GRINDING DOES NOT INCREASE THE PRECISION OF THE INTEGRATED INTENSITY MEASUREMENTS. A VIBRATORY BALL MILL IS USED FOR THE FINAL GRINDING. SAMPLES HAVING RANDOM ORIENTATION ARE OBTAINED BY USING A SPECIAL HOLDER INTO WHICH THE POWDER IS ALLOWED TO FALL GENTLY WITHOUT COMPACTING IT. SAMPLES PREPARED AS DESCRIBED GAVE HIGHLY REPRODUCIBLE TOTAL INTENSITIES. /PCA/]]></description>
      <pubDate>Mon, 01 Jun 1970 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/102037</guid>
    </item>
    <item>
      <title>NEW TECHNIQUES FOR TEMPERATURE AND HUMIDITY CONTROL IN X-RAY DIFFRACTOMETRY</title>
      <link>https://trid.trb.org/View/102088</link>
      <description><![CDATA[A PHILIPS ELECTRONICS GEIGER COUNTER DIFFRACTOMETER HAS BEEN MODIFIED TO PROVIDE CONTROL OF THE TEMPERATURE OF THE SAMPLE AND THE HUMIDITY AND COMPOSITION OF THE ATMOSPHERE SURROUNDING THE SAMPLE. SPECIAL SAMPLE HOLDERS CONTAINING WATER RESERVOIRS HAVE BEEN DEVISED FOR USE IN STUDIES OF SYNTHETIC MIXTURES OF CEMENT COMPONENTS WHILE UNDERGOING HYDRATION. THE TECHNIQUES OF USING THE MODIFIED EQUIPMENT ARE ILLUSTRATED BY TWO EXAMPLES TAKEN FROM STUDIES ON THE CALCIUM ALUMINATE HYDRATES. A VARIETY OF ADDITIONAL APPLICATIONS OF THESE TECHNIQUES ARE INDICATED. /PCA/]]></description>
      <pubDate>Mon, 01 Jun 1970 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/102088</guid>
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