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The rate of percutaneous absorption of micro-particles is very important due to its effects on human health. In this study, a new approach is proposed to investigate both the lateral and the longitudinal diffusions during the absorption of a micro-particle. The results of the current 2D model are compared with the results of a previous 1D model. According to the results, the influence of lateral diffusion on the rate of percutaneous absorption is important, especially for the lipohilic materials. On the other words, the difference between the results of the two models is more significant, at lower values of the ratio of viable-epidermis-diffusivity to the stratum-corneum-diffusivity (DVE/DSC), or at lower values of the viable epidermis to the stratum corneum partition-coefficient (kVE/kSC). For instance, when DVE/DSC equals to 1 and kVE/kSC is 0.33, for a particle with a radius of 10 µm, the steady-state-molar-flux estimated by the 2D model is 2.37 times greater than that estimated by the 1D model...

The surface tension of binary mixtures at different temperatures and compositions is required in much scientific and technological research. Therefore, having an exact correlation between surface tension and easily accessible physical properties is essential. In this work, the sensitivity of the surface tension to some physical properties was studied by using artificial neural networks (ANNs) to find the most effective ones. Furthermore, ANNs were used to estimate the surface tension of binary systems as a function of the most effective physical properties including critical pressure, reduced temperature, acentric factor, and molar density. The experimental data, collected for training and verifying the networks, include various materials such as alkanes, alkenes, aromatics, alcohols, organic acids, as well as chlorine, iodine, sulfur, nitrogen, and fluorine-containing compounds in the composition ranges from 0 to 100 mole percent, and temperatures between 116 K and 393 K. The average absolute relative de...

This article presents a new approach to investigate the kinetics of sunflower and rapeseed oils methanolysis. Due to its heterogeneous nature, the methanolysis reaction is affected by different physical properties such as mass transfer coefficients and specific surface area of the dispersed phase. Considering these parameters, a model was developed, and was evaluated by comparing the results of the model with the experimental data found in the literature. The mean absolute deviation obtained for sunflower and rapeseed oils is 0.039 mol L−1, which demonstrates the accuracy of the model. The results show that the mixing speed is more effective in the first few minutes of the process. Furthermore, at mixing speed above 700 rpm, the process is controlled only by the reactions. The rate of biodiesel production increases with increasing catalyst concentration; however, catalyst concentration above 1.5 wt% has little or no significant effect on the rate of biodiesel production. In addition, because of its higher...