Support Vector Machine and Its Difficulties From Control Field of View

The application of the Support Vector Machine (SVM) classification algorithm to large-scale datasets is limited due to its use of a large number of support vectors and dependency of its performance on its kernel parameter. In this paper, SVM is redefined as a control system and Iterative Learning Control (ILC) method is used to optimize SVM’s kernel parameter. The ILC technique first defines an error equation and then iteratively updates the kernel function and its regularization parameter using the training error and the previous state of the system. The closed-loop structure of the proposed algorithm increases the robustness of the technique to uncertainty and improves its convergence speed. Experimental results were generated using nine standard benchmark datasets covering a wide range of applications. Experimental results show that the proposed method generates superior or very competitive results in term of accuracy than those of classical and stateof-the-art SVM-based techniques while using a significantly smaller number of support vectors

Effect of Mono and Di-rhamnolipids on Biofilms Pre-formed by Bacillus subtilis BBK006.

Different microbial inhibition strategies based on the planktonic bacterial physiology have been known to have limited efficacy on the growth of biofilms communities. This problem can be exacerbated by the emergence of increasingly resistant clinical strains. Biosurfactants have merited renewed interest in both clinical and hygienic sectors due to their potential to disperse microbial biofilms. In this work, we explore the aspects of Bacillus subtilis BBK006 biofilms and examine the contribution of biologically derived surface-active agents (rhamnolipids) to the disruption or inhibition of microbial biofilms produced by Bacillus subtilis BBK006. The ability of mono-rhamnolipids (Rha-C10-C10) produced by Pseudomonas aeruginosa ATCC 9027 and the di-rhamnolipids (Rha-Rha-C14-C14) produced by Burkholderia thailandensis E264, and phosphate-buffered saline to disrupt biofilm of Bacillus subtilis BBK006 was evaluated. The biofilm produced by Bacillus subtilis BBK006 was more sensitive to the di-rhamnolipids (0.4 g/L) produced by Burkholderia thailandensis than the mono-rhamnolipids (0.4 g/L) produced by Pseudomonas aeruginosa ATCC 9027. Rhamnolipids are biologically produced compounds safe for human use. This makes them ideal candidates for use in new generations of bacterial dispersal agents and useful for use as adjuvants for existing microbial suppression or eradication strategies

Direct dimethyl ether (DME) synthesis through a thermally coupled heat exchanger reactor

Compared to some of the alternative fuel candidates such as methane, methanol and Fischer-Tropsch fuels, dimethyl ether (DME) seems to be a superior candidate for high-quality diesel fuel in near future. The direct synthesis of DME from syngas would be more economical and beneficial in comparison with the indirect process via methanol synthesis. Multifunctional auto-thermal reactors are novel concepts in process intensification. A promising field of applications for these concepts could be the coupling of endothermic and exothermic reactions in heat exchanger reactors. Consequently, in this study, a double integrated reactor for DME synthesis (by direct synthesis from syngas) and hydrogen production (by the cyclohexane dehydrogenation) is modelled based on the heat exchanger reactors concept and a steady-state heterogeneous one-dimensional mathematical model is developed. The corresponding results are compared with the available data for a pipe-shell fixed bed reactor for direct DME synthesis which is operating at the same feed conditions. In this novel configuration, DME production increases about 600 Ton/year. Also, the effects of some operational parameters such as feed flow rates and the inlet temperatures of exothermic and endothermic sections on reactor behaviour are investigated. The performance of the reactor needs to be proven experimentally and tested over a range of parameters under practical operating conditions.Direct DME synthesis Coupling exothermic and endothermic reaction Cyclohexane dehydrogenation Auto-thermal reactor

Utilization of wheat straw for fungal phytase production

Purpose Wheat straw is an agricultural waste which can be used as a cost effective animal feed. However, high hemicellulose and phytic acid content in wheat straw prevents it as a primary feed choice. Utilization of wheat straw in solid-state fermentation may result in wheat straw valorization and enzyme production. In this study, phytase production in solid-state fermentation of wheat straw using Aspergillus ficuum and valorization of wheat straw were evaluated. Methods A two-step experimental design procedure was employed for screening and optimization of influencing factors on phytase production. Effects of different nutritional and environmental factors were investigated by one factor at the time method (OFATM). To reach higher amounts of phytase, response surface methodology (RSM) was employed to optimize phytase production as a function of three of the most effective factors. Results Optimization of the significant parameters resulted in an increase in the phytase activity from 0.74 ± 0.12 to a maximum of 16.46 ± 0.56 Units per gram dry substrate (U gds−1). The high degree of the fungal phytase activity on wheat straw resulted in the decrease in phytic acid content by 57.4%, as compared to the untreated sample. Scanning electron microscopy (SEM) and FTIR structural analysis showed intensive fungal growth on wheat straw, and partial removal of hemicelluloses, lignin and phytic acid. Conclusion The study demonstrated the feasibility of wheat straw utilization in solid-state fermentation using Aspergillus ficuum toward the production of phytase and valorization of wheat straw as an animal feed