View More View Less
  • 1 Technical University of Budapest Institute for General and Analytical Chemistry Gellért tér 4 H-1521 Budapest Hungary
Restricted access

Abstract  

Novel methods of unified evaluation of two (or more) thermogravimetric curves have been worked out on the basis of known non-linear parameter estimating procedures (Gauss-Newton-Marquardt-type regression and the direct integral method of Valkó and Vajda were adapted). Their ability to provide estimate for common kinetic parameters of several TG (m−T) or DTG (dm/dt-T) curves were tested for pairs of curves of different heating rates, and for repeated curves of the same heating rate, obtained for the decomposition of CaCO3 in open crucible. In these cases the Arrhenius terms and then-th order model functions were assumed. The fitting ability of estimations made for single curves and for pairs of curves sharing different number of parameters, was judged on the base of residual deviations (Sres) and compared to the standard deviation of the measurements. In the case of different heating rates, the two curves could not be described with the assumption of three common parameters, because of the minimum residual deviation was very high. However, sharing of activation energy and preexponential term only, and applying different exponents for the two curves, provided a satisfactory fit by our methods. Whilst in the case of repeated curves, we could find such a common three-parameter set, which has a residual deviation comparable with the standard deviation of the measurements. Because of their flexibility (taking into account the variable number of common parameters and the versatile forms of model equations), these methods seem to be promising means for unified evaluation of several related thermoanalytical curves.

Manuscript Submission: HERE

  • Impact Factor (2019): 2.731
  • Scimago Journal Rank (2019): 0.415
  • SJR Hirsch-Index (2019): 87
  • SJR Quartile Score (2019): Q3 Condensed Matter Physics
  • SJR Quartile Score (2019): Q3 Physical and Theoretical Chemistry
  • Impact Factor (2018): 2.471
  • Scimago Journal Rank (2018): 0.634
  • SJR Hirsch-Index (2018): 78
  • SJR Quartile Score (2018): Q2 Condensed Matter Physics
  • SJR Quartile Score (2018): Q2 Physical and Theoretical Chemistry

For subscription options, please visit the website of Springer.

Journal of Thermal Analysis and Calorimetry
Language English
Size A4
Year of
Foundation
1969
Volumes
per Year
4
Issues
per Year
24
Founder Akadémiai Kiadó
Founder's
Address
H-1117 Budapest, Hungary 1516 Budapest, PO Box 245.
Publisher Akadémiai Kiadó
Springer Nature Switzerland AG
Publisher's
Address
H-1117 Budapest, Hungary 1516 Budapest, PO Box 245.
CH-6330 Cham, Switzerland Gewerbestrasse 11.
Responsible
Publisher
Chief Executive Officer, Akadémiai Kiadó
ISSN 1388-6150 (Print)
ISSN 1588-2926 (Online)