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-step reaction [ 6 , 7 ], in which the Arrhenius parameters (activation energy and pre-exponential factor) vary with dehydration degree. Therefore, it's difficult to use a single pair of Arrhenius parameters to reveal the chemical mechanism and to predict the

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Journal of Thermal Analysis and Calorimetry
Authors: Dragica M. Minić, Maja T. Šumar-Ristović, Đenana U. Miodragović, Katarina K. Anđelković, and Dejan Poleti

kinetic triplet involving Arrhenius parameters (an activation energy, E and a pre-exponential factor, Z ) as well as an algebraic expression of the conversion function, f ( α ), which describes the dependence of the reaction rate on the conversion

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Abstract  

The degradation of cellulose and starch samples in air and nitrogen has been investigated by thermal analysis techniques. The techniques employed were differential thermal analysis, rising temperature and temperature jump thermogravimetry. Rate data were obtained from these experiments and Arrhenius parameters calculated from these values. This data was used to determine the mechanism by which the cellulose and starch samples degraded. The Arrhenius parameters were also calculated. The behavior of starch and cellulose upon thermal analysis were compared and are reported.E act for corn starch was found to be 474 kJ mol−1 and for a cellulose 242 kJ mol−1.

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Abstract  

The oxidation of glutathione and thioglycolic acid by pertechnetate ion has been studied. In each case a reaction mechanism is proposed which is in agreement with the experimental kinetic orders, and which satisfactorily accounts for all other experimental findings. Rate constants and Arrhenius parameters are reported.

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Abstract  

The combustion of two different sewage sludges and a semianthracite coal was studied and compared by thermogravimetric analysis. Non-isothermal thermogravimetric data were used to evaluate the Arrhenius parameters (activation energy and the pre-exponential factor) of the combustion of these carbonaceous materials. The paper reports on the application of model-free isoconversional methods for evaluating and comparing the corresponding activation energy of the combustion process.

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Abstract  

The relation between the structure of olefins and oxygen-containing compounds and their reactivity in radical addition, substitution and isomerization processes under γ-irradiation in a wide temperature range was examined. Correlation equations for the determination of elementary rate constants and their Arrhenius parameters are given. The compensation effect is discussed. A mechanism of product formation is proposed and the corresponding kinetic equations are derived from the steady-state principle.

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Summary Non-isothermal thermogravimetric data were used to evaluate the Arrhenius parameters (activation energy and the pre-exponential factor) of the combustion of two carbonaceous materials, selected as diesel soot surrogates. The paper reports on the application of model-free isoconversional methods (Flynn-Wall-Ozawa and Kissinger methods) for evaluating the activation energy of the combustion process. On the other hand, by means of the compensation relation between E and lnA, which was established by the model-dependent Coats-Redfern method, the value of the pre-exponential factor was estimated from the known value of the model-independent activation energy.

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Journal of Thermal Analysis and Calorimetry
Authors: S. Sivapirakasam, M. Surianarayanan, F. Chandrasekaran, and G. Swaminathan

Abstract  

DSC studies of cracker mixtures of different compositions of potassium nitrate, sulphur and aluminum have shown some critical characteristics either with the increase or decrease in the composition of the components. Specifically, sulphur composition below 8% showed no exothermic activity. The studies revealed that a minimum of 11% to a maximum of 17% of sulphur is required for good cracking characteristics. The kinetics of decomposition of cracker mixture is carried out employing DSC multiple heating rate kinetic method. Increase in sulphur content decrease the energy of activation facilitating easy ignition of the cracker mixtures. Arrhenius parameters for cracker mixture decomposition are reported in this paper.

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