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Abstract  

An improved method for the synthesis of four heterotrinuclearpolyacids of the type: Hx[EM′yM″zO40nH2O (E=P, Si; M′=Mo, W; M″=V, W) was elaborated. The studied compounds were characterized by elemental analysis, IR spectra and thermal behaviour over 20–800C temperature range.

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Abstract  

Thermal behaviour of raw fly ashes-wasted products from various Polish power plants has been investigated using X-ray diffractions (XRD), Fourier transform infrared spectroscopic (FT-IR), differential thermal analysis (DTA) and thermogravimetry (TG). On the basis of the DTA and TG analysis differentiation between examined ashes has been made, which could not be achieved by XRD and FT-IR methods.

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Journal of Thermal Analysis and Calorimetry
Authors: E. Plevová, A. Kožušníková, L. Vaculíková, and G. Simha Martynková

Abstract  

The definition as well as prediction of rock thermal behavior seems to be a quite difficult problem significantly effected by rock composition and structure. Temperature increase causes various changes of rock material (such as decomposition, oxidation, phase and polymorphic transformation, etc.). These changes are connected to thermal expansion with following appearance of tensions and cracks in minerals and rock structure. After consequential temperature decrease, developed tensions and cracks still influence the process. This study presents the application of thermogravimetric analysis, differential thermal analysis and thermomechanical analysis in characterization of selected marble thermal behavior. The texture and morphological orientation of calcite grains for marble samples was determined by optical microscopy. FTIR spectroscopy application along with X-ray diffraction (XRD) extended data about mineralogical composition. According to optical microscopy, the calcite grains show marked morphological anisotropy in one direction for some samples. Therefore, the thermal expansion had to be measured in three different (perpendicular to each other) directions. It is evident, that the effect of temperature on the final marble properties depends not only on mineralogical composition, but also on structure, texture and morphological orientation of grains. All these facts significantly influence the interpretation of differences in various marble thermal behavior.

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Journal of Thermal Analysis and Calorimetry
Authors: Agnieszka Jabłońska–Wawrzycka, Małgorzata Zienkiewicz, Maciej Hodorowicz, Patrycja Rogala, and Barbara Barszcz

gain information on: influence of the type of manganese(II) salt applied to the synthesis on the product of the reaction; influence of the furnace atmosphere on the thermal behavior and on

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Abstract  

The thermal behaviour of ammonium oxofluorotitanates (NH4)3TiOF5, (NH4)2TiOF4 and NH4TiOF3 was investigated by thermoanalytical, X-ray and IR spectroscopic methods. The first decomposition stages under quasi-isobaric conditions are characterized by the formation of (NH4)2TiF6 and ammonium oxofluorotitanate with the less content of ammonium and fluorine than in the initial compound. The decomposition process is accompanied by the Ti(IV) reducing due to ammonia evolved. The new ammonium oxofluorotitanate of high volatility was isolated and characterized. Ammonium-containing non-stoichiometric titanium oxyfluorides are the final products of thermal decomposition of ammonium oxofluorotitanates.

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Abstract  

Parent and mixed ligand complexes of cobalt and copper with antipyrine derivatives of 1,2-ethanediamine or piperazine and with 2-aminobenzothiazole (TAB) were synthesized and their thermal behaviour was investigated. The complexes contain N,N′-bis(4-antipyrylmethyl)-piperazine (BAMP) or N,N′-tetra(4-antipyrylmethyl)-1,2-diaminoethane (TAMEN) or/and TAB as ligand, and Cl, ClO4 or SCN. The complexes decompose with the evolution of heat. The decomposition route depends on the presence of ClO4 . If the ClO4 is not coordinated, it oxidizes the TAB and BAMP or TAMEN and the decomposition is explosive.

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Journal of Thermal Analysis and Calorimetry
Authors: L. Ji-zhen, F. Xue-zhong, H. Rong-zu, Z. Xiao-dong, Z. Feng-qi, and G. Hong-Xu

Abstract  

The thermal behavior of copper(II) 4-nitroimidazolate (CuNI) under static and dynamic states are studied by means of high-pressure DSC (PDSC) and TG with the different heating rates and the combination technique of in situ thermolysis cell with rapid-scan Fourier transform infrared spectroscopy (thermolysis/RSFTIR). The results show that the apparent activation energy and pre-exponential factor of the major exothermic decomposition reaction of CuNI obtained by Kissinger’s method are 233.2 kJ mol−1 and 1017.95 s−1, respectively. The critical temperature of the thermal explosion and the adiabatic time-to-explosion of CuNI are 601.97 K and 4.4∼4.6 s, respectively. The decomposition of CuNI begins with the split of the C-NO2 and C-H bonds, and the decomposition process of CuNI under dynamic states occurs less readily than those under static states because the dynamic nitrogen removes the strong oxidative decomposition product (NO2). The above-mentioned information on thermal behavior is quite useful for analyzing and evaluating the stability and thermal charge rule of CuNI.

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Journal of Thermal Analysis and Calorimetry
Authors: S. Jingyan, L. Jie, D. Yun, H. Ling, Y. Xi, W. Zhiyong, L. Yuwen, and W. Cunxin

Abstract  

The thermal behavior of nicotinic acid under inert conditions was investigated by TG, FTIR and TG/DSC-FTIR. The results of TG/DSC-FTIR and FTIR indicated that the thermal behavior of nicotinic acid can be divided into four stages: a solid-solid phase transition (176–198°C), the process of sublimation (198–232°C), melting (232–263°C) and evaporation (263–325°C) when experiment was performed at the heating rate of 20 K min−1. The thermal analysis kinetic calculation of the second stage (sublimation) and the fourth stage (evaporation) were carried out respectively. Heating rates of 1, 1.5, 2 and 3 K min−1 were used to determine the sublimation kinetics. The apparent activation energy, pre-exponential factor and the most probable model function were obtained by using the master plots method. The results indicated that sublimation process can be described by one-dimensional phase boundary reaction, g(α)=α. And the ‘kinetic triplet’ of evaporation process was also given at higher heating rates of 15, 20, 25, 30 and 35 K min−1. Evaporation process can be described by model of nucleation and nucleus growing,
\documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{upgreek} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} $$g(\alpha ) = \left[ { - \ln (1 - \alpha )} \right]^{\frac{1} {3}}$$ \end{document}
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Abstract  

Taking into account the importance of thermal stability in the liquid crystals field, the study presents thermal behavior of some cholesteric esters, which differ by the nature of the functional group attached to the cholesteryl unit and the connecting position of the nitro or amino functions to the aromatic ring. The cholesteric esters present liquid crystalline properties, with high melting and clearing points and may be used as intermediates in the synthesis of liquid crystals. Some other kinetic characteristics, such as reaction order (n), activation energy (E a) and pre-exponential factor (lnA) have been also evaluated. The type of functional units adjacent to the aromatic unit determines thermal stability of the cholesteryl compounds. Groups with a powerful withdrawing effect induce a decreasing of the temperatures at which the material starts to lose mass. An increased thermal stability for the amino esters has been observed, probably because of some intermolecular hydrogen bonds formation.

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Abstract  

The thermal behaviour of the intercalation complex of a dickite from Tarifa, Spain, with dimethylsulfoxide was studied by high-temperature X-ray diffraction, differential thermal analysis and thermogravimetry, and attenuated total reflectance infrared spectroscopy. The ATR-FTIR study indicated that the heating between room temperature and 75C produced the elimination of adsorbed molecules. Above this temperature the elimination of intercalated molecules occurs through several stages. Loss of 6.5% of the intercalated DMSO first causes a slight contraction of the basal spacing at 90şC due to a rearrangement of the DMSO molecules in the interlayers positions. This contraction is followed by the formation of a single layer complex and the restoring of the dickite structure, at 300C, when the loss of intercalated species have been completed.

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