ABSTRACT
In the present work, an optimization method called Particle Swarm Optimization (PSO) was applied to study the kinetics of alkali-catalyzed rapeseed oil transesterification, using methanol, in a batch process. The validation of the PSO program was realized using numerical and experimental data from literature. The PSO method resulted in a 4 times lower error compared to classic methods used in the domain, which showed its efficiency and strength. After validation, an experimental study was led on the transesterification of rapeseed oil and methanol in a batch process using KOH as catalyst (1wt/wt %) with a methanol:oil molar ratio of 6:1 at 45 °C, 55 °C and 65 °C respectively. Then, PSO was used in order to determine the reaction rate constants ( k j m ) of the reversible 3-steps of transesterification mechanism as well as the kinetic parameters (activation energy Ea and pre-exponential factor A). Then, the kinetic model was used in order to investigate the effects of methanol: oil molar ratio variation (3:1, 4:1, 5:1, 6:1, 8:1, 12:1) on rate constants, yield and conversion rate at 65 °C. The results of the simulation showed a perfect agreement with experimental results.
ABSTRACT
Twenty five non-atopic scabietic patients were examined to estimate their reaction to crude house dust mite Dermatophagoides farinae (D. farinae) and storage mite Tyrophagus putrescentia (T. putrescentiae) antigens. Skin prick testing (SPT) by extracts of both mites antigens showed significant higher positive results in scabietics when compared to non-scabietic control subjects. Moreover, 60% and 56% of scabietic patients showed positive levels of specific anti-D. farinae and T. putrescentia IgE respectively in comparison to 13.4% & 20% of control subjects. A significant difference has been obtained when the total number of positive results were compared to the total number of negative ones. The results revealed that there is an evidence of cross reactivity between Sarcoptes scabiei antigens and extracts of D. farinae and T. putrescentiae, and the hypersensitivity to house dust mite and storage mite antigens was significantly higher in scabietics than in controls. It could be concluded that there is some proof that other mites rather than Sarcoptes scabiei may have a role in the pathogenesis of scabies and the cross reactivity between S. scabiei and house dust mite and storage mite may explain the persistence of symptoms in some cases even after proper treatment of the disease.
