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Abstract  

This research was aimed to investigate the combustion and kinetics of oil shale samples (Mengen and Himmetoğlu) by differential scanning calorimetry (DSC). Experiments were performed in air atmosphere up to 600�C at five different heating rates. The DSC curves clearly demonstrate distinct reaction regions in the oil shale samples studied. Reaction intervals, peak and burn-out temperatures of the oil shale samples are also determined. Arrhenius kinetic method was used to analyze the DSC data and it was observed that the activation energies of the samples are varied in the range of 22.4–127.3 kJ mol−1 depending on the oil shale type and heating rate.

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. Typically thermogravimetric (TG) analysis or hot-stage microscopy (HSM) are employed in tandem with DSC analysis since all can record data with linear heating rates. However, much progress in interpretation of DSC data can be made simply by recording data

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revealed here by TG/DTG and DSC methods. In addition, the influence of heating rate and atmosphere on the thermal behavior of cefuroxime lysine was investigated here. Moreover, the kinetic parameters for chemical decomposition were calculated by using the

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Journal of Thermal Analysis and Calorimetry
Authors: Yunbo Zhai, Wenfeng Peng, Guangming Zeng, Zongming Fu, Yuanming Lan, Hongmei Chen, Chang Wang, and Xiaopeng Fan

sizes of sewage sludge and three heating rates were employed to study the pyrolysis process. And a new method is employed to compute the pyrolysis kinetics parameters based on the TG curves. Experimental section

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this area. For example, in 1995, Seetarama [ 12 ] tried to study the existing diffusion reactions in MoSi 2 propagation synthesis and the effect of heating rate on the mechanism of the performance of this process by the thermal analysis test. In a

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the point of separation between two mass loss stages. The model was verified to be suitable for the mass loss processes of variable wood and leaf samples under relatively lower heating rates (mostly 10 K min −1 ). In the subsequent researches by other

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evaluating the solid state kinetic parameters [ 1 , 2 ]. The evaluation of the kinetic parameters has often been done by using a single thermogravimetric curve (TG curve) recorded at a certain heating rate. Some recent results on thermal and thermo

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Journal of Thermal Analysis and Calorimetry
Authors: Katsumi Katoh, Shunsuke Ito, Shuhei Kawaguchi, Eiko Higashi, Katsuyuki Nakano, Yuji Ogata, and Yuji Wada

Abstract  

In the previous study, it was observed that the stability of nitrocellulose (NC) cannot be determined by thermal analyses such as differential scanning calorimetry (DSC) at heating rates of 1–10 K/min. This was because the thermal curves of NC samples with different stabilities could not be distinguished from one another. In this study, we explain why such thermal analyses cannot be used to evaluate the thermal stability of NC and identify the conditions under which thermal analyses can be used for this purpose. We investigated the effect of heating rate on the thermal behavior of pure NC and NC stabilized with diphenylamine (DPA) or akarditeII (AKII), which is a conventional stabilizer, by using the heat flux calorimeter (C80). At high heating rates (0.2–0.3 K/min), only single exothermic peak was observed in the thermal curves of both pure NC and NC/DPA and the thermal curve of pure NC was practically similar to that of NC/DPA. At low heating rate (0.02 K/min), two exothermic peaks were observed for both pure NC and NC/DPA. The heat amount of the first peak depended on the partial pressure of O2 in the atmosphere. The first peak in the thermal curve of NC/DPA was slightly suppressed as compared to that of pure NC. These results indicate that the stability of NC probably depends on the first exothermic peak that represents oxidation of NC by atmospheric O2. From this, on the thermal analyses at high heating rates, thermal curves of pure NC and NC/DPA could not be distinguished from one another. This is because the decomposition of NC itself occurs in the second exothermic peak before the oxidation of NC by atmospheric O2 in the first peak, which is attributed to the stability of NC. The results of the thermal analyses under isothermal conditions at 393 K in an O2 atmosphere revealed that the induction period of NC/DPA and NC/AKII was longer than that of pure NC. From these results, it is speculated that the stability of NC can be evaluated by thermal analyses carried out under O2-rich conditions at low heating rates.

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Abstract  

A differential method is proposed which uses local heating rates to evaluate non-isothermal kinetic parameters. The method allows to study the influence of the deviation of the true heating rate with respect to the programmed one on the values of the kinetic parameters. For application, the kinetic parameters of the following solid-gas decomposition reaction were evaluated: [Ni(NH3)6]Br2(s)→[Ni(NH3)2]Br2(s)+4NH3(g). The results obtained revealed significant differences between the values of the non-isothermal kinetic parameters obtained by using local heating rates and those obtained by using the programmed heating rate. It was also demonstrated that the kinetic equation which makes use of the local heating rates permits a better description of the experimental (α, t) data than the kinetic equation which uses the programmed constant heating rate.

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The thermal decomposition of Eucalptus Camaldulensis and Cotton Stalks at different heating rates showed three exothermic peaks. The heating rate is the factor that affects their sharpness and position. The peaks are sharp at low heating rates. IR spectra of pyrolized residue at different temperature were also studied.

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