scholarly journals Numerical Integration of Weight Loss Curves for Kinetic Analysis

Thermo ◽  
2021 ◽  
Vol 1 (1) ◽  
pp. 32-44
Author(s):  
Juan A. Conesa
Keyword(s):  
Weight Loss ◽  
Kinetic Analysis ◽  
Kinetic Parameters ◽  
Numerical Integration ◽  
Integration Procedure ◽  
Actual Temperature ◽  
Complex Processes ◽  
Decomposition Curve ◽  
Numerical Integration Procedure

Research abounds in the literature on kinetic analyses using thermogravimetric (TG) runs. Many of these studies use approximations of integral or derivative forms of the kinetic law and all of them use programmed temperatures. In the present work, a numerical integration procedure was discussed and applied to different examples. We focused on materials presenting a single decomposition curve as well as other materials with more complex processes. Different examples were explored, and the methodology was applied to a number of wastes such as coffee husks, polystyrene and polyethylene. In all cases, the actual temperature measured by thermocouples close to the sample is used, and several runs are fitted using the same kinetic parameters, giving robustness to the results.

scholarly journals Numerical Integration of Weight Loss Curves for Kinetic Analysis

2021 ◽  
Author(s):  
Juan A. Conesa
Keyword(s):  
Weight Loss ◽  
Numerical Methods ◽  
Kinetic Analysis ◽  
Numerical Integration ◽  
Actual Temperature ◽  
Complex Processes ◽  
Kinetics Of Decomposition ◽  
Kinetics Of ◽  
Decomposition Curve ◽  
Numerical Integration Procedure

Research abounds in the literature on kinetic analyses using thermogravimetric (TG) runs. Many of these studies use approximations of integral or derivative forms of the kinetic law and all of them use programmed temperature, not the actual temperature measured by thermocouples close to the sample. In addition, it is common to conduct a single run in order to perform the calculation. Nevertheless, many authors consider that numerical methods should be used to analyse the kinetics of decomposition. In such cases, the actual temperature is used and, generally, several runs are fitted using the same kinetic parameters, giving robustness to the results. In the present work, a numerical integration procedure was discussed and applied to different examples. We focused on materials presenting a single decomposition curve as well as other materials with more complex processes. Different examples were explored, and the methodology was applied to a number of wastes such as coffee husks, polystyrene and polyethylene.

The use of gas-liquid chromatography to determine activity coefficients and second virial coefficients of mixtures I. Theory and verification of method of data analysis

1966 ◽  
Vol 295 (1442) ◽  
pp. 259-270 ◽  
Keyword(s):  
Numerical Integration ◽  
Retention Volume ◽  
Simple Extension ◽  
Gas Liquid Chromatography ◽  
Local Pressure ◽  
Integration Procedure ◽  
Carrier Gas ◽  
Wide Range ◽  
Analytical Integration ◽  
Numerical Integration Procedure

This paper reformulates the differential equation describing the local elution rate in a g. l. c. column in terms of the local pressure and the carrier gas outlet flow rate. Analytical integration for an ideal carrier gas suggests an accurate method for extrapolating a function of the retention volume linearly to zero pressure, where the intercept V ° N is simply related to the thermodynamic activity coefficient of the solute (1) in the stationary liquid (3) and the gradient β gives B 12 for the mixture solute + carrier gas (2). We argue that a simple extension of the method should apply also, with fair accuracy, to a non-ideal carrier gas. We support this argument with data obtained by a numerical integration procedure which gives retention volume in terms of specified V ° N and B for a range of inlet and outlet pressures. The reliability of the numerical integration procedure is established by comparing results for the ideal gas case with the results of analytical integration. The retention volumes obtained by numerical integration for a non-ideal carrier gas are then treated as ‘experimental’ observations, using in addition to our extrapolation procedure, two previously published procedures. Our procedures are consistently more successful than the others and recover accurately the V ° N originally specified over a wide range of flow conditions, even when the carrier gas shows large deviations from ideality. In the case of β , our method is significantly in error only when the carrier gas deviates largely from ideality in a low pressure column with large pressure drop. A simple refinement of our method is satisfactory for even this case.

scholarly journals Evaluation of astrophysically useful parameters for strontium monohydride and deuteride

2006 ◽  
pp. 13-16 ◽  
Author(s):  
Sri Ramachandran ◽  
N. Rajamanickam ◽  
S.P. Bagare
Keyword(s):  
Numerical Integration ◽  
Transition Probabilities ◽  
Integration Procedure ◽  
Giant Stars ◽  
Condon Factors ◽  
Astrophysical Molecules ◽  
Franck Condon ◽  
Numerical Integration Procedure

The Franck-Condon factors and r-centroids which are very closely related to transition probabilities, have been evaluated by the more reliable numerical integration procedure for the band systems B2?-X2?, C2?-X2? and F2?-X2? of astrophysical molecules strontium monohydride and strontium deuteride using an adequate potential. The Franck-Condon factors are more intense, particularly for the ?? = 0 bands, for all the systems examined here. Thus the bands of the molecules are expected to be present in sunspot spectra, SC-stars, cool M-giant stars and other prominent astrophysical sources.

Franck-Condon Factors and R-Centroids for the Band System a1Π-X1Σ+ of the InH Molecule

1993 ◽  
Vol 58 (7) ◽  
pp. 1491-1494 ◽  
Author(s):  
Narayanan Rajamanickam ◽  
Thangamariappan Murali ◽  
Thangasamy Sakthivel ◽  
Manuel Fernandez Gomez ◽  
Juan Jesus Lopez Gonzalez
Keyword(s):  
Numerical Integration ◽  
Transition Probabilities ◽  
Band System ◽  
Vibrational Transition ◽  
Integration Procedure ◽  
Condon Factors ◽  
Franck Condon ◽  
Suitable Potential ◽  
Numerical Integration Procedure

The Franck-Condon factors (vibrational transition probabilities) and r-centroids have been evaluated by a numerical integration procedure for the bands of the a3Π1-X1Σ+ system of the InH molecule using a suitable potential.

scholarly journals An alternative approach to kinetic analysis of temperature-programmed reaction data

RSC Advances ◽  
2018 ◽  
Vol 8 (6) ◽  
pp. 3286-3295 ◽  
Author(s):  
A. S. Portnyagin ◽  
A. P. Golikov ◽  
V. A. Drozd ◽  
V. A. Avramenko
Keyword(s):  
Particle Size ◽  
Kinetic Analysis ◽  
Kinetic Parameters ◽  
Isothermal Reaction ◽  
Alternative Approach ◽  
Reaction Data ◽  
Temperature Programmed ◽  
Temperature Programmed Reaction

Presented method of kinetic analysis of non-isothermal reaction data provides precise kinetic parameters for different materials with different morphology and particle size.

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