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Abstract  

The Modified Entrainment Method developed by Faktor et al. [1] is an attractive yet not very popular method to determine vapour pressures in the range of 0.002 to 0.1 bar at 10–1000°C. The method consists of evaporating a solid or liquid from a small bulb through a capillary into a flowing inert gas, e.g. argon. The vapour pressure of the sample is related to the rate of evaporation and some easily controlled experimental parameters. In the present paper a new convenient experimental set-up is described and its use to study the decomposition of metal complexes is illustrated.

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Community Ecology
Authors: C. Vieira da Silva, I. Bianchini Jr., J. F. Gonçalves Jr., R. A. Oliveira, and R. Henry

.O. Gessner . (eds.), Methods to Study Litter Decomposition: a Practical Guide . Springer , Dordrecht . pp. 223 – 229 . Abelho , M. , C. Cressa and M. Graça . 2005 . Microbial

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Thermal decomposition of methylxanthines

Interpretation of the results by PCA

Journal of Thermal Analysis and Calorimetry
Authors: M. Wesolowski and P. Szynkaruk

Abstract  

The thermal decomposition of theophylline, theobromine, caffeine, diprophylline and aminophylline were evaluated by calorimetrical, thermoanalytical and computational methods. Calorimetrical studies have been performed with aid of a heat flux Mettler Toledo DSC system. 10 mg samples were encapsulated in a 40 μL flat-bottomed aluminium pans. Measurements in the temperature range form 20 to 400°C were carried out at a heating rate of 10 and 20°C min−1 under an air stream. It has been established that the values of melting points, heat of transitions and enthalpy for methylxanthines under study varied with the increasing of heating rate. Thermoanalytical studies have been followed by using of a derivatograph. 50, 100 and 200 mg samples of the studied compounds were heated in a static air atmosphere at a heating rate of 3, 5, 10 and 15°C min−1 up to the final temperature of 800°C. By DTA, TG and DTG methods the influence of heating rate and sample size on thermal destruction of the studied methylxanthines has been determined. For chemometric evaluation of thermoanalytical results the principal component analysis (PCA) was applied. This method revealed that first of all the heating rate influences on the results of thermal decomposition. The most advantageous results can be obtained taking into account sample masses and heating rates located in the central part of the two-dimensional PCA graph. As a result, similar data could be obtained for 100 mg samples heated at 10°C·min−1 and for 200 mg samples heated at 5°C min−1.

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–MS coupling technique to study the catalytic effect of NiO nanoparticles on the thermal decomposition of EGDN/NC propellant. It was shown that adding 2% of NiO nanoparticles to TEGDN/NC propellant can accelerate the thermal decomposition process after around

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19 291 298 Chapman, S. K., S. C. Hart, N. S. Cobb, T. G. Whitham and G. W. Koch. 2003. Insect herbivory increases litter quality and decomposition

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decomposition behaviors of CMDB propellant have been investigated by differential scanning calorimetry (DSC) and burning characteristics have been reported [ 5 , 6 ]. In our present work, we have studied the composite modified double-base propellant containing

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Introduction Thermal decomposition and dehydration of metal acetates have been studied broadly under various conditions [ 1 – 20 ]. As a typical and widely applied metal acetate, the thermal decomposition of copper(II) acetate

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application of these methods in studies on chemical stability and thermal degradation of drug substances and medicinal products [ 7 – 11 ]. Among others, the studies were carried out to identify kinetic parameters of decomposition processes of some antibiotics

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Abstract  

In this study, the decomposition behavior of four dolomite samples of different origin was studied by X-ray diffractometer and simultaneous TG-DTA experiments. Three different decomposition regions were determined known as dehydration of inter-particle water, formation of MgO and calcite and decomposition of calcite. Kinetic analysis of these decomposition regions was analyzed and the related activation energies are determined. It was observed that the activation energies were in the range of 48–137 kJ mol−1.

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consisting in quenching followed by isothermal transformation: (1) processing window: stability of structure α ac + γ s (C) (2) During the first stage of isothermal austenite γ(C o ) decomposition, ausferrite with fine acicular ferrite α ac and

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