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, ...
Corresponding States Method for Evaluation of the Solubility Parameters of Chemical Compounds
In this study, our objective is to apply the gene expression programming mathematical algorithm to propose a correlation based on the corresponding states method to determine the solubility parameters of 1641 pure compounds (mostly organic ones) at 298.15 K and atmospheric pressure. The studied compounds are from the 80 chemical families. The parameters of the method include the critical temperature, critical pressure, molecular weight, and acentric factor. Around 1477 solubility parameter data are randomly selected for developing (training + optimization) the correlation, and about 164 data are used for checking its prediction capability. The obtained statistical parameters, including average absolute relative deviation of the results from the applied data (about 6%), show the accuracy of the proposed method along with its simplicity and wide range of applicability.
Evaluation of Lapping Grains based on Shape Characteristics.
The shape and size of abrasive grains during lapping varies complicately and irregularly. In this study, the aspect ratio of grain size and the fractal dimension of the grain external form were used as shape characteristics of grain in order to evaluate grains with lapping time. The results obtained are summarized as follows : (1)The fractal dimension increases due to microscopic fracture and decreases due to macroscopic fracture or attritious wear. (2)The aspect ratio and the fractal dimension, which are grain shape characteristicsis of the macroscopic shape and the microscopic surface complication of grain respectively, can be used for evaluating grain shape variation during lapping.