Thermal analysis

Differential thermal analysis and reaction kinetics for nth-order reaction

“…On the one hand, Equation 2 has been assumed in DTA involving some gas-solid and solid decomposition reactions, as in the classic work by Murray and White (8), by Kissinger (9), and by others. On the other hand, in DTA involving phase transitions, the reactions were terminated at the peak temperatures and Equation 2 is not applicable (10)(11)(12). However, by using simultaneous DTA-DTG techniques, for the types of reactions that will be discussed in this work, it has been clearly shown that the DTA and the DTG correspond quite well (13).…”

Application of thermal analytical methods in the characterization of carbonaceous materials

“…This neutron source is suitable for exciting aluminum, since the average neutron energy is lower than that of ( , ) sources (e.g., Pu-Be), resulting in less interference from the fast neutron reaction 28Si(n,p)28Al, as discussed later. The 252Cf source was located at the bottom of a 10-cm diameter hole (9 cm deep) in a cylindrical polyethylene block to obtain a well thermalized neutron flux (7). The y rays from the decay of the radioisotope 28A1 were detected with a 126 X 126 mm Nal(Tl) detector.…”

“…KINETIC ANALYSES OF DTA CURVES Extraction of kinetic information from DTA curves is, in general, limited to reactions with simple rate expressions (6,7). For reactions with more complicated rate expressions, the approximate methods outlined by Kissinger (8) and by Yang and Steinberg (6) can also be applied; but the results would be lengthy and the mathematics tedious, and therefore such analyses would not be of practical interest.…”

“…From this analysis, it can be seen that only one peak is possible in the first-order and pseudo-second-order reactions while two peaks, or a bifurcated peak, can occur for the pseudo-thirdorder reaction. EXPERIMENTAL AT = k(dx/dt) (7) The above assumptions are not unrealistic in the gas-carbon reactions in which diffusion is not the rate-controlling step and the reactions proceed uniformly throughout the sample.…”

Inorganic and geological materials

“…Reviews of various techniques in thermal analysis have been prepared by Murphy in the 1974 Fundamental Reviews (130), and by Wendlandt (198); reviews of thermometric and enthalpimetric titrations have been prepared by Bark ( 9 ) , Bark et al (IO), Beezer ( 1 4 ) , and Hansen et al (82).…”