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Abstract  

Tin-doped indium oxide In2O3 (indium-tin-oxide) transparent conducting films were fabricated on silicon substrates by a dip coating process. The thermal analysis of the ITO films was executed by temperature-programmed desorption (TPD) or thermal desorption spectroscopy (TDS) in high vacuum. Gas evolution from the ITO film mainly consisted of water vapor. The total amount of evolved water vapor increased on increasing the film thickness from approx. 25 to 250 nm and decreased by increasing the preparation temperature from 365 to 600C and by annealing at the same temperature for extra 10 h. The evolution occurred via two steps; the peak temperatures for 250 nm thick films were approx. 100-120 and 205-215C. The 25 nm thick films evolved water vapor at much higher temperatures; a shoulder at approx. 150-165C and a peak at approx. 242C were observed. The evolution temperatures increased by increasing the preparation and the annealing temperatures except in case of the second peak of the 25 nm thick films. The evolution of water vapor at high temperature was tentatively attributed to thermal decomposition of indium hydroxide, In(OH)3, formed on the surface of the nm-sized ITO particles.

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Abstract  

Approximately one million tons of semicoke (SC) is formed and stored in open air dumps every year in the production of shale oil by processing Estonian oil shale (OS). The content of different harmful compounds as sulphides, PAH, phenols, etc. in SC make these dumps one of the most serious sources of environmental contamination. The aim of this work was to study the behaviour of sulphur compounds in OS and its SC, formation of SO2 and possibilities of binding it into the solid phase during thermooxidation of fuel blends based on SC. Blends modified with SC ash addition were studied as well. It was determined that SO2 emission in thermooxidation of SC samples started at 280-300C and proceeded with a steady speed up to 580-600C and the amount of sulphur evolved was 5-10% from the total content of sulphur in the sample. The amount of SO2 emitted decreased depending on the mass ratio of the composite fuels from 49-56 to 15-35% during thermooxidation of OS samples studied or their blends with SC, respectively, from 43-80% for coal samples to 13-60% for their blends with SC and to 2-13% during thermooxidation of these blends modified with SC ash addition. In the products of thermooxidation formed at 800-900C the only sulphur containing phase was CaSO4, at 650C also traces of CaS and CaMg3(SO4)4 were fixed.

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A versatile and flexible system is described for evolved gas analysis using a GLC, MS (mass scan and SIM modes) and GLC-MS. Gases evolved from materials in two differential thermal analysis units, a thermobalance or a micro-furnace linked directly to the MS or GLC can be analysed. Details are given of computer controlled data acquisition and processing. The techniques are applied to the thermal decomposition of calcium propanoate. Mechanisms are suggested to account for the observed decomposition products and the solid state process. Evidence is presented to support the view that the latter occurs via nucleation followed by two-dimensional growth with an activation energy of 315 kJ mol−1 and a pre-exponential factor of 4.8×1021s−1.

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Abstract  

Emanation thermal analysis (ETA) was used to characterize microstructure changes during heating of Mg–Al–CO3 layered double hydroxide (LDH) in the temperature range of 293–1473 K. It was confirmed by ETA that the formation of an intermediate phase with grafted CO3 2– anions in the hydroxide layers took place in the temperature range of 508–523 K and the formation of Mg–Al mixed oxide (MO) occurred in the range 623–773 K. The small peak of the emanation rate at 603 K indicated the degradation of the layered structure and the broad peak in the range of 1073–1273 K characterized the onset of the separation of the decomposition products of MO into MgO and Mg2Al4O7. The ETA results revealed that dehydration of the product with grafted CO3 2– anions occurred at lower temperatures than that of the initial Mg–Al–CO3 LDH.

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