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(O) is formed, while CO 2 is reduced to CO. Then, C f (O) is broken into CO. This is the slowest step of the reaction. Chen et al. [ 3 ] also proposed a reaction mechanism for carbon gasification. They considered that, in addition to C f , CO 2 is

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activity and selectivity at temperatures near the operating temperature of proton exchange membrane (PEM) fuel cells [ 1 – 5 ]. Despite the extensive research carried out in the field, controversies still remain related to the reaction mechanism and the

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Abstract  

Two kinds of compensation mechanism are suggested: a genuine one due to thermodynamic factors and a pseudo one arising from experimental or data-processing artifacts. It is computationally demonstrated that the choice of reaction mechanism strongly influences the kinetic parameters determined in thermal analytical studies. It is further shown that the kinetic parameters determined at different heating rates by using a pseudo reaction mechanism exhibit kinetic compensation that gives the temperature of the experiment as the so-called isokinetic temperature. A rule of thumb relating to the magnitude of the isokinetic temperature is suggested to differentiate genuine compensation from pseudo compensation.

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Abstract  

Thermogravimetry is often used to study polymer degradation. Most often the information obtained may have some practical application but is of limited value for the determination of fundamental processes which may be occurring. A kinetic expression or activation parameters for a complex process which may involve consecutive or parallel reactions provides almost no information about any of the reactions that might be occurring. However, for single, well-defined processes, thermogravimetry, in conjugation with other analytical methods, can be effectively utilized in the determination of reaction mechanism. The thermal degradation of vinylidene chloride barrier polymers corresponds to the elimination of hydrogen chloride initiated at an allylic dichloromethylene unit in the mainchain. This process is uncomplicated by competing reactions. Thermogravimetry may be utilized to obtain meaningful rate constants and activation parameters for the degradation. This in conjunction with mass spectral analysis of evolved gas, characterization of both the polymer and degradation residue by ultraviolet, infrared and 1H and 13C NMR spectroscopy, and the study of model compounds has permitted a detailed description of the degradation process. General purpose poly(styrene) is a commodity polymer widely used in the food packaging industry as well as many others. If processed at excessively high temperature, it undergoes thermal degradation to expel styrene monomer which can impart negative flavor and aroma characteristics to packaged food items. The degradation reaction has been fully detailed using thermogravimetry in conjugation with evolved gas analysis, size exclusion chromatography and NMR spectroscopy.

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Reaction Kinetics, Mechanisms and Catalysis
Authors: F. J. Lona-Ramírez, R. Herrera-Muñoz, V. Rico-Ramírez, F. Louvier Hernández, G. Luna-Bárcenas, and G. González-Alatorre

work presents the results obtained from a kinetic study of the nitrosation of 1,1,3-nitrosotrimethylurea, including both the validity of the Arrhenius equation and the reaction mechanism. Experimental The solutions were

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Abstract  

The reaction mechanism of the synthesis of Fe8V10W16O85 was studied by means of XRD, IR spectroscopy and DTA techniques. It was found that the intermediate in the reaction may be either FeVO4 or FeVO4 admixed with an unidentified phase X, depending on the reaction temperature. The IR spectrum of the phase Fe8V10W16O85 is reported for the first time.

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formation of • NO 2 by modeling based on a detailed reaction mechanism. Experimental Most of the experimental data are from our already reported work [ 8 ]. Three-week-old male Wistar rats were kept under standard conditions

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Abstract  

An established DTA/T/EGD/GC on-line coupled simultaneous technique and relevant equipment were applied to identify the micro impurity minerals—pyrite and siderite in two kinds of dolomite in air and N2. The proportional five-component mixed minerals (siderite, kaolinite, dolomite, calcite and quartz) and the proportional six-component mixed minerals (pyrite and the above five minerals) were detected in N2 and in air/CO2 (1∶1) separately by applying DTA/EGD/GC and DTA/GC. The experimental results provide the basis for demonstration of the reaction mechanism of thermal decomposition of various gas—solid-phase minerals in N2 and air/CO2. The compositions of six-component mixed minerals can be distinguished individually from the DTA/GC curves; reliable results are obtained.

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Invar® oxidation in CO2

Kinetics and mechanism of formation of a wüstite layer

Journal of Thermal Analysis and Calorimetry
Authors: S. Menecier, S. Valette, P. Denoirjean, and P. Lefort

– it proves that the reaction mechanism is the same for all the considered time; – it allows determining directly the apparent activation energy and the pressure law without any assumption about the

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