Abstract
The temperature integrals\(p_m (x) = \int_x^\infty {e^{ - x} u^{ - 2 - m} du} \) with m=0, 1/2 and 1 are approximated using empirical formulae of the type Ax−Be−Cx. For estimation of the precision of these approximations, the relative errors were calculated for integral values ofx. It was established that forx < 19 the maximum relative error is 0.26%, while for 19 ≤x<50 it is less than 0.1%. The suggested approximations allow a sensible improvement of the integral methods intended to determine the kinetic parameters of the process concerned.
Zusammenfassung
Fürm-0, 1/2 und 1 werden Temperaturintegrale der Form\(p_m (x) = \int_x^\infty {e^{ - x} u^{ - 2 - m} du} \) du mit empirischen Formeln des TypesAx −B e −Cx näherungsweise berechnet.
Zur Bestimmung der Genauigkeit dieser Näherung wurde für Integralwerte vonx der relative Fehler berechnet. Der maximale relative Fehler liegt fürx < 19 bei 0.26% und ist im Intervall 19≤x≤50 kleiner als 0.1%.
Die vorgeschlagenen Näherungen erlauben eine wesentliche Verbesserung von Integriermethoden zur Bestimmung kinetischer Parameter diesbezüglicher Prozesse.
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References
J. H. Flynn and L. A. Wall, J. Res. NBS, 70A (1966) 487.
C. Zahra, L. Lagarde and R. Romanetti, Thermochim. Acta, 6 (1973) 145.
G. Ehrlich, Adv. in Catal. and Related Subjects, 14 (1963) 255.
R. Chen, J. Appl. Phys. 40 (1969) 570.
J. Van Turnhout, Polymer J., 2 (1971) 173.
J. P. Baur, D. W. Bridges and W. M. Fassel, J. Electrochem. Soc., 102 (1955) 490.
P. Vallet, Tables numériques permettant l'integration des constants de vitesse par raport à la température, Gauthier-Villars, Paris, 1961, p. 13.
J. R. Biegen and A. W. Czanderna, J. Thermal Anal., 4 (1972) 39.
J. Saint-Georges and G. Garnaud, J. Thermal Anal., 5 (1973) 599.
“Tables of Sine, Cosine and Exponential Integrals”, Vols. I and II, Federal Works Agency, Work Products Administration for City of New-York, 1940.
J. R. MacCallum and J. Tanner, Europ. Polymer J., 6 (1970) 1033.
C. D. Doyle, J. Appl. Polymer Sci., 5 (1961) 285.
A. W. Coats and J. P. Redfern, Nature 201 (1964) 68.
C. D. Doyle, Nature, 207 (1965) 290.
R. C. Turner and M. Schnitzer, Soil Sci. 93 (1962) 225; Chem. Abstr., 59 (1963) 14518.
J. Zsakó, J. Thermal Anal., 8 (1975) 593.
M. Balarin, J. Thermal Anal., 12 (1977) 169.
G. I. Senum and R. T. Yang, J. Thermal Anal., 11 (1977) 445.
N. Hajduk and J. Norwisz, J. Thermal Anal., 13 (1978) 223.
T. B. Tang and M. M. Chaudhri, J. Thermal Anal., 18 (1980) 247.
J. Behnisch, E. Schoof and H. Zimmermann, J. Thermal Anal., 13 (1978) 117.
G. G. Cameron and J. D. Fortune, Europ. Polymer J., 4 (1967) 333.
V. Haber, J. Appl. Polym. Sci., 10 (1966) 1185.
F. Škvara and Šesták, J. Thermal Anal., 8 (1975) 477.
I. Agherghinei and V. Iurea, unpublished data.
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This paper was presented at the National Congress of Chemistry, Bucuresti, Sept. 11–14, 1978; in Abstracts, Pt. 1, 151 (1978).
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Agherghinei, I. Thermogravimetry. Empirical approximation for the “temperature integrals”. Journal of Thermal Analysis 36, 473–479 (1990). https://doi.org/10.1007/BF01914501
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DOI: https://doi.org/10.1007/BF01914501