Showing papers in "Thermochimica Acta in 1989"

TL;DR: In this article, the ability to determine the actual reaction mechanism (RM) of solid state processes from a single nonisothermal curve was analyzed and discussed, and it was found that the reaction follows the R3 mechanism which is in very good agreement with the results of isothermal experiments.

TL;DR: A BASIC program is described which enables the kinetic analysis of thermoanalytical experimental data obtained under non-isothermal conditions, including direct comparison of experimental and theoretically calculated data.

TL;DR: Controlled transformation rate thermal analysis (CTRTA) as mentioned in this paper is a general thermoanalytical method where, instead of controlling the temperature (as in conventional thermal analysis), one controls some other physical or chemical property, which is made to follow a pre-determined program by appropriate heating of the sample.

TL;DR: In this paper, several calcium-deficient hydroxyapatites (DAp) samples were synthesized by aqueous precipitation under controlled conditions, and compared with an equimolar mixture of HAp and dicalcium phosphate (DCP).

TL;DR: In this article, a new high temperature calorimeter based on modifications and improvements to the commercial integrated heat flux Setaram design is described, which is tested at 1473 K through the measurement of the enthalpies of formation of intermetallic compounds.

TL;DR: In this paper, the most frequently used kinetic models with respect to the boundary conditions of a rate equation are discussed, where the molar concentration of reactants is frequently replaced by the so-called degree of conversion (a) which is usually defined as 111 ~,=(c,GMGo-G) 0)

TL;DR: In this paper, the thermal decomposition of the basic carbonate hydrates of lanthanides and yttrium has been studied and the results show that the TG and DTA curves are characteristic for each compound.

TL;DR: In situ X-ray diffraction (XRD) was used to elucidate the thermal decomposition of dolomite as discussed by the authors, where data was collected at 4 ° C intervals while continuously heating the sample at 3 ° C min−1.

TL;DR: In this article, pressure differential scanning calorimeter (PDSC) exotherms were extracted and used for assessment of the oxidative stabilities of the oils, including corn, soybean, corn and sunflower oils.

TL;DR: In this paper, the thermal stability of ammonium nitrate-water-in-oil emulsions was evaluated using differential scanning calorimetry in combination with conventional isothermal techniques.

TL;DR: The need for thermodynamic data on polymer solutions over a broad temperature range is discussed and presented as the justification for the development of highly sensitive, precise differential scanning calorimeters as discussed by the authors.

TL;DR: In this paper, the thermal decomposition of a commercial composite solid propellant binder, hydroxy-terminated polybutadiene (HTPB), was studied by thermogravimetry-derivative TEG-differential scanning calorimetry simultaneous techniques (TG-DTG-DSC) applied simultaneously at heating rates varying from 8 to 60°C min −1.

TL;DR: In this article, the authors used differential scanning calorimetry (DSC) combined with sample dispersal in the form of an emulsion to study the kinetics of both homogeneous and heterogeneous nucleation of ice in an aqueous sample.

TL;DR: In this article, a detailed analysis of the following effects influencing the ionization processes is presented: solvation effects on a molecule having the same atom in different positions on its skeleton.

TL;DR: In this paper, the influence of composition, content of water, production methods, aging and heat treatment is shown by the changed melting characteristics and the solid-liquid ratio of emulsified fats.

TL;DR: In this article, a computer program was written in FORTRAN and BASIC languages for calculating enthalpy changes of complex formation in solution from direct calorimetric measurements, which can deal with any system in which mononuclear, polynuclear, protonated, hydroxo, mixed metal or mixed ligand complexes are formed.

TL;DR: In this article, the results obtained with different lignocellulosic materials (Pinaster pine and barley straw) are compared with those calculated by considering the weighted contributions of the different constituents of the materials.

TL;DR: In this article, the authors studied the composition dependence of excess differential coefficients related to the pVT dependence of free energies and free enthalpies in the water + methanol system.

TL;DR: In this paper, the adsorption and the thermal stability of the organo-clay complexes were studied by IR thermospectrometry, and it was concluded that the hydrophobicity of the clays increases and their thermal stability decreases as a result of the adorption of the organic bases.

TL;DR: In this article, the authors discussed the determination of heat capacities with power compensating DSC using the continuous measuring method and compared the results with reference values for heat capacity and enthalpy at the extreme states the material can be in.

TL;DR: In this article, the oxidation of pyrite of particle size less than 45 μm has been studied by simultaneous thermogravimetry- differential thermal analysis (TG- DTA) at a heating rate of 2.5 ° C min−1 in an air atmosphere.

TL;DR: In this article, the calibration factor is not constant but depends on experimental parameters such as calibration method heating rate, temperature and sample mass, which cannot be neglected for precision measurements, and a temperature gradient in the bottom of the sample holder leads to different temperature reading using different positions or different sample pans.

TL;DR: In this article, the effects of experimental variables (i.e., sample weight, particle size, purge gas velocity and crystalline structure) on the observed kinetic parameters of calcium carbonate decomposition were studied.

TL;DR: In this article, the equilibrium quotient for the protonation of diethanolamine (DEA), 2-(2-aminoethoxy) ethanol or diglycolamine (DGA), and N -methyldiethanolamines (MDEA) was determined potentiometrically over the ionic strength range 0.004-4.0 at 298.2 K.

TL;DR: In this paper, the kinetics of weight loss in the thermal decomposition of xylan and lignin in a nitrogen environment have been studied thermogravimetrically, and the results from isothermal and dynamic experiments at different heating rates are related by using the results of dynamic experiments with low heating rates (1.5 °C min−1) as a reference.

TL;DR: A thermogravimetric analyzer built on the basis of a Cahn 2000 electrobalance, suitable for using with corrosive atmospheres, has been reported in this paper, where the authors studied the kinetics of a reaction between Cl2 and a mixture of ZrO2 and C. They showed evidence of a transition to quite a different reaction rate at longer times.

TL;DR: The 9th ICTA Congress on thermal analysis of minerals other than clays as discussed by the authors reviewed the contribution of new advanced technologies in traditional thermal analysis methods to the study of earth materials.

TL;DR: In this paper, the existence of a large number of unwettable domains on the vessel walls which cause gas accumulation is shown to be inconsistent with the cohesion theory of water transport.

TL;DR: In this paper, the surface of LaNiO 3 and the interactions of CO, CO 2 and hydrogen with this perovskite were studied as a function of the reduction temperature of the oxide.

TL;DR: In this paper, the authors studied the thermal behavior of M(acac)n/support materials, in which M = Pd2+, Pt2+, MoO2+2, Fe3+, Ru3+ or Ni2+ and support = SiO2, γ-Al2O3 or TiO2.