Accession Number : ADD095349

Title :   A Combined Least Sums and Least Squares Approach to the Evaluation of Thermodynamic Data Networks.

Descriptive Note : Interim rept.,

Corporate Author : NATIONAL STANDARD REFERENCE DATA SYSTEM

Personal Author(s) : Garvin, David ; Parker, Vivian B ; Wagman, Donald D ; Evans, William H

Report Date : Jul 1976

Pagination or Media Count : 41

Abstract : A description is given of a system for computer-based evaluation of interrelated thermodynamic measurements of enthalpies of reaction, equilibria and entropies. This system is an extension of the CATCH program developed by J. B. Pedley, University of Sussex. In the new system linear least sums and least squares techniques are used to solve networks of thermodynamic equations to obtain the enthalpies and free energies of formation and the entropies of chemical substances. The least sums technique is shown to be useful in assessing the consistency of the data. A method combining least sums and least squares solutions, provides a weighted combining least sums and least squares solutions, provides a weighted solution that reproduces closely the solutions that are obtained by a detailed analysis of the data using the customary sequential procedure. The results from tests on four large networks involving compounds of B, U, Rb and salts of Sn, Pb, Cd and Hg are discussed. (Author)

Descriptors :   *COMPUTER APPLICATIONS, *DATA BASES, *THERMOCHEMISTRY, *THERMODYNAMIC PROPERTIES, FREE ENERGY, LEAST SQUARES METHOD, COMPUTERS, MEASUREMENT, ENTHALPY, HEAT OF REACTION, EQUILIBRIUM(GENERAL), ENTROPY, SEQUENTIAL ANALYSIS, FITTING FUNCTIONS(MATHEMATICS), METALS, SALTS, TEST AND EVALUATION

Subject Categories : Physical Chemistry

Distribution Statement : APPROVED FOR PUBLIC RELEASE