1) Th· Infl iMiic· off Expérimental Variable· on t h · Th*rmogravim*trk Determination of Activation Energies, Κ G. Wiedemann, A. V. Tets, H. P. Vaughan, Preprint of a paper presented at the Pittsburgh Con­ference on Analytical Chemistry and Applied Spec­troscopy. February 21, 1966 Thermogravimctric analysis has often been used to derive activation energy values by the measurement of the decomposition rate of chemical compounds. This paper discusses some of the instrumental, sample geometry and atmospheric factors which influence the reproducibility of rate determinations. An ex­ample is given showing the decomposition of mag­nesium oxalate.

2) New Automatic Derivative Computer Aide Quan­titative Thermogram Interpretation, Technical Bul­letin T-102, Mettler Instrument Corporation A bulletin describes the operation and application of the new Mettler Derivative Computer accessory. The new accessory makes possible simultaneous measurement of TGA/DTA/DTG. The derivative trace (DTC) is graphically similar to the DTA trace and is thus a great aid in simultaneous comparison of heat and weight change phenomena. The automatic DTG is also useful in quantitative measurements of reac­tion rates used in the study of kinetics.

Five new technical reports from Mettler on simultaneous TGA/DTA/DTG

3) A New Semi^Micfo Sample HoMer Assembly for Simultaneous TlioiiitoQrovimotnc and Differential Thermal Analysis, Hans-Ceorg Wiedemann, Re­print from % Zeltschrift fur analytische Chemie," VoL 220, p. 81-88 (1966) This paper describes the design and use of a new simultaneous TCA/DTA sample holder for semi-mi­cro thermal analysis. Enthalpy values for the mono-clinic-rhombic-hexagonal conversion of sodium sul­fate are derived as examples using the differential calorimetry technique. Special design features in­crease the reproducibility of DTA measurements for quantitative analysis.

4) Determination off Strain Energy in Muscovite by Simultaneous Measurement off Enthalpies and Weight Loss, William Lodding, Reprint of a paper presented at the Annual Meeting of the American Institute of Mining, Metallurgical & Petroleum Engi­neers, February 27 to March 3, 1966 The simultaneous quantitative measurement of DTA and DTG peak areas leads to a measurement of a solid state crystalline reaction which was otherwise obscured by a dehydroxilation. Simultaneous DTA/ DTG measurements on an unmodified sample were compared with DTA/DTG measurements on a sam­ple where strain energy was released by mechanical grinding. Careful measurements of the DTA/DTG peak area ratios leads to the determination of the strain energy value.

5) Thermal Analysis in Corrosive Gas Atmospheres, Technical Bulletin T-103, Mettler Instrument Corp. The use of controlled gas atmospheres is, of course, a necessity in the study of gas/solid reactions in which gas atmosphere is a rate controlling factor. Heretofore many pieces of apparatus were limited regarding the use of the corrosive gases or samples which decomposed giving off corrosive gas effluents, thus restricting many possible fields of study. A sys­tem is described which permits the use of corrosive gases as reaction atmospheres which, at the same time, affords complete protection for the working mechanisms.

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Mettler Instrument Corporation, Dept. C E N 20 Nassau Street, Princeton, N. J. 08 540

Please send me copies of the following Technical Reports on Simultaneoi TGA/DTA/DTG: No. 1 LJ - No. 2 ΤΊ - No. 5 Ζ - No. 4 I_] - No. 5 I

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20 Nassau St., Princeton, N. J.