The aim of this study was to correlate the results of experimental data using DTA method and predictions of artificial neural
network (ANN) and multivariate linear regression (MLR). Thermal decomposition of polymers was analyzed by simultaneous DTA
method, and kinetic parameters (critical points, the change of enthalpy and entropy) of polymers were investigated. A computer
model based on multilayer feed forwarding back propagation and multilayer linear regression model were used for the prediction
of critical points, phase transitions of low-density polyethylene (LDPE) and mid-density polyethylene. As a result of our
study, we concluded that ANN model is more suitable than MLR about prediction of experimental data.
A method for comparing the thermochemical properties of high- boiling fractions and residues has been developed. The thermal effects vary in intensity and range, depending on the fractional and structure group compositions of the studied samples. Good agreement between DTA and TG data is observed. The thermal analysis of samples, obtained by liquid adsorption chromatography, reveals the specific differences of the individual structure group fractions in the processes of evaporation, thermal decomposition and coke formation. The observed effects are interpreted from the point of view of the different thermal stabilities and reactivities of the compounds contained in the Chromatographic fractions. The results show that the TG-DTA method allows the quick determination of some characteristics depending on the group compositions of the high-boiling fractions and residues from West Siberian crude oiL.
Authors:V Vinciguerra1, R Bucci, F Marini, and A Napoli
The thermal decomposition
of iminodiacetic, oxydiacetic, and thiodiacetic acids in helium atmosphere
has been studied by means of thermogravimetry (TG), differential thermal analysis
(DTA) and temperature-programmed pyrolysis directly coupled with mass spectrometry
(TPPy-MS). Evolved gas analysis (EGA) profiles of iminodiacetic and oxydiacetic
acids were obtained and compared with TG and DTA profiles.
of iminodiacetic acid forms water, CO, CO2, CH3CN,
HCN and some hydrocarbons. After water evolution a cyclic anhydride is formed,
as well as for oxydiacetic acid. Thiodiacetic acid vaporizes without decomposition.
This research was aimed
to investigate the role of clay on the combustion and kinetic behavior of
crude oils in limestone matrix. For this purpose, simultaneous TG (thermogravimetry)
and DTA (differential thermal analysis) experiments were performed at three
different heating rates as 10–15 and 20C min–1,
respectively. A uniform trend of decreasing activation energies was observed
with the addition of clay. It was concluded that clays surface area affects
the values of Arrhenius constant, while it is the catalytic properties of
clay, which lower the activation energies of all the reactions, involved in
the combustion process.
Diopside, CaO.MgO.2SiO2, and glasses of the same stoichiometry are fundamental phases in non-ferrous slags. Samples of this composition, prepared from the melt at different cooling rates, were examined via DTA and IR spectra. A correlation was found between the degree of vitrification and the magnitude of the exothermic effect at around 870 °C. The same dependence exists for some slags. No exotherm was observed for well-crystallized samples. The reactivity with water was assigned to the glass content.