Corresponding States Method for Estimation of Upper Flammability Limit Temperature of Chemical Compounds
The accuracy and predictability of predictive methods to determine the flammability characteristics of chemical compounds are of drastic significance in the chemical industry. This work aims at continuing application of the gene expression programming (GEP) mathematical strategy to modify the existing thermophysical properties correlations available in the literature to pursue the following objectives: optimization of the number of independent parameters, amplification of the generality, and improvement of the accuracy and predictability. This work deals with presenting a simple corresponding states model to predict the upper flammability limit temperature of 1462 organic compounds from 76 chemical families. The parameters of the correlation include the critical temperature and the acentric factor of the compounds. The obtained statistical parameters including average absolute relative deviation of the results from DIPPR 801 database values (1.7, 1.8, 1.7% for training, optimization, and prediction sets, ...
Prediction of the Upper Flammability Limit of Pure Compounds
A quantitative structure-property relation model was developed to predict the upper flammability limit (volume percent in air) of pure compounds, based only in their structures. A group contribution method was used to determine the upper flammability limit (UFL) through an artificial neural network. The method was used to identify the structure groups that have a significant contribution to the target property and concluded that 30 atom-type structure groups can represent the UFL for 550 pure substances. The models input parameters are the number of occurrence of each of the 30 structure groups in the molecule. The model predicts UFL with a correlation coefficient of 0.9996 and average absolute deviation of 0.17 vol %. The results were compared with multivariable regression model and other methods in the literature. The model is very useful and convenient for accessing the hazardous risk potential of chemicals for which experimental data is not available.
SR topography of plastically deformed Fe-Si bicrystals - observation in situ and post mortem
SR reflection topography was applied to study the interaction of slip dislocations with the grain boundaries in Fe-4at%Si bicrystals deformed by compression. Three experimental settings with either a white or monochromatic beam were used and the corresponding orientation contrast analysed. Dislocation transmission through the grain boundary was observed in bicrystals with favourable geometry of the slip systems.