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Three DTA peaks (two endo and one exothermic) were replotted in the form of ∑ peak area.Δa, or ∑ peak magnitude,ΔT, as a function of temperature. The integral sigmoid curves were plotted in the form of logg(α) vs. 1/T or log logg(α)/T 2 vs. 1/T. Both of the proposed summation methods gave satisfactory straight lines (F 1 function), characterized by the same activation energies, correlation coefficients and standard deviations. Integration of the peak areas by Simpson's rule resulted in the same values as obtained by the summation procedure. Analysis by the suggested integral method resulted in activation energies that show a logarithmic divergence relative to the magnitude ofE a estimated directly from the DTA peaks.

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A computer program has been worked out for the following requirements: (1) The program is to render a listing of the elements detected, together with their respective concentrations, not just an evaluation of the gamma-spectrum (peak energies and areas). (2) There should be no necessity to intermediate decisions, i.e. execution of the program should be possible by auxiliary personnel. (3) Gamma-ray spectra recorded under widely different conditions should be amenable to evaluation. This implies a large range of variation of the number of channels per peak. (4) In order to have the most extensive capability of executing multi-element analyses instrumentally, it must be possible to evaluate complex spectra with many superpositions. The program involves the fitting of Gaussians. It is shown that this evaluation method gives more precise peak area determinations than the summation method and also yields reasonable results in the case of strong superposition.

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force field [ 37 ]. The combined force field has been successfully used in the simulations of organo-montmorillonite composites. A 15.0 Å cutoff was used for the short-range interaction. The Ewald summation method was used to calculate Coulombic

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