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Journal of Thermal Analysis and Calorimetry
Authors: Késia K. V. Castro, Ana A. D. Paulino, Edjane F. B. Silva, Thiago Chellappa, Maria B. D. L. Lago, Valter J. Fernandes Jr., and Antonio S. Araujo

monitored by TG, using integral dynamic curves at multiple heating rates, and the activation energy was estimated from the Flynn–Wall kinetic model [ 9 , 10 ]. Experimental section Synthesis The Al-MCM-41

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[ 6 , 7 ]: where ρ is the density of the material, f is the frequency factor, E a is the activation energy of sublimation, and K B is Boltzmann's constant. Considering a homogeneous sublimation of the material from the surface, hence

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Thermal properties of oxide glasses

Part IV. Induction period of crystallization as a criterion of thermal stability of M2OSiO2 (M = Li, Na) glass systems against crystallization

Journal of Thermal Analysis and Calorimetry
Authors: S. Lendvayová, K. Moricová, E. Jóna, J. Kraxner, M. Loduhová, V. Pavlík, J. Pagáčová, and S. C. Mojumdar

). Several authors [ 8 , 9 ] suggested that the crystallization activation energy could also be used to evaluate the glass stability, but criteria based on the activation energy, or crystallization rate constants do not always fit with the actual

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( Fig. 6a , b) from the non-isothermal DTG data. From the slope, the activation energy ( E a ) for the decomposition of the complex was calculated ( Table 2 ). The activation energy values obtained are 28 ± 3.4, 31 ± 4.2, 39 ± 4.6 kJ mol −1 for stage I

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; ( 2 ) diffusion curve; diamond 100 °C; downturned triangel 70 °C; circle 55 °C; star 35 °C; filled triangle 20 °C Activation energy determination The activation energy of

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(Version 2004.05) program [ 7 ]. A special Model Free program based on the well-known works [ 8 – 17 ] allows the processing of several thermogravimetric curves obtained with different heating rates and the calculation of the activation energy without the

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Journal of Thermal Analysis and Calorimetry
Authors: Marcelo Kobelnik, Douglas Lopes Cassimiro, Clóvis. A. Ribeiro, Jorge M. V. Capela, Diogines S. Dias, and Marisa S. Crespi

with different sample masses and using a cover on the crucible as well as crimped lids. In these different conditions, the effects of the different masses employed demonstrated that the activation energy becomes lower with an increase in the sample mass

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the pre-exponential factor, R is the universal gas constant (8.314 J mol −1 K −1 ), E a is the apparent activation energy of the cure reactions (J mol −1 ), and T is the isothermal cure temperature (K). The apparent activation energy of the 977

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assumed to have Arrhenius dependence with temperature: (19) where E is the activation energy, R is the universal gas constant and k 0 is a pre-exponential factor. After the estimation of each kinetic constant, its activation energy and pre

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isothermal as well as non-isothermal [ 2 – 6 ] environment. To analyze the data obtained from DSC and hence to obtain kinetic parameters of the crystallization processes (such as activation energy, rate constant, etc.), there are several methods available in

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