In this paper we consider the evolutionary Particle Swarm Optimization (PSO) algorithm, for the minimization of a computationally costly nonlinear function, in global optimization frameworks. We study a reformulation of the standard iteration of PSO [KE95, CK02] into a linear dynamic system. We carry out our analysis on a generalized PSO iteration (see [M04]), which\ud
includes the standard one proposed in the literature.\ud
We analyze three issues for the resulting generalized PSO: first, for any particle we give both theoretical and numerical evidence on an efficient choice of the starting point. Then, we study\ud
the cases in which either deterministic and uniformly randomly distributed coefficients are considered in the scheme. Finally, some convergence analysis is also provided, along with some\ud
necessary conditions to avoid diverging trajectories. The results proved in the paper can be immediately applied to the standard PSO iteration
Coconut is a tropical fruit largely consumed in many countries. In some areas of the Brazilian coast, coconut shell represents more than 60% of the domestic waste volume. The coconut shell is composed mainly of lignin and cellulose, having a chemical composition very similar to wood and suitable for phenolic extraction. In this work, the use of ultrasound to extract phenolic compounds from coconut shell was evaluated. The effect of temperature, solution to solid ratio, pH and extraction time were evaluated through a 2(4) experimental planning. The extraction process was also optimized using surface response methodology. At the optimum operating condition (30 degrees C, solution to solid ratio of 50, 15 min of extraction and pH 6.5) the process yielded 22.44 mg of phenolic compounds per gram of coconut shell.
Several researchers have used crude glycerol as a source of substrate for methane production and power generation, which is a way of adding value to this residue that has a high chemical oxygen demand (COD) and is rich in impurities. This review article summarizes recent data and discussions on the use of crude glycerol as substrate and co-substrate for anaerobic digestion. In general, the dilution of glycerol has been used to avoid problems of inhibition due to the presence of inorganic salts of chloride and sulphates, and due to accumulation of metabolites. However, other methods have been proposed, such as the use of halo-tolerant biomass. It can be concluded that the anaerobic digestion of crude glycerol is technically viable, and an anaerobic reactor treating 25 m 3 per day of crude glycerol can produce 4.4 MW of thermal energy, which can be converted to 4.4 GW of heat or 1.2 GW of electricity.
In the present work, the use of low-cost substrates to produce Trichoderma spores was evaluated. Rice, corn bran, and wheat bran were used as solid substrate to grow Trichoderma harzanium sp., Trichoderma viride sp., Trichoderma koningii sp., and Trichoderma polysporum sp. No external nutrient sources were added to the solid substrate that was only moisturized with deonized water, sterilized, inoculated, and cultivated at 30°C for 7 days. Wheat bran showed to be the most suitable substrate to produce Trichoderma spores for all strains that were evaluated. High spore counts were obtained for T. harzianum sp. (28.30×10 8 /gds) and T. viride sp. (24.10×10 8 spores/gds).
The use of agriculture substrates in industrial biotechnological processes has been increasing because of its low cost. Cashew apples are considered an agriculture low cost product in the Brazilian Northeast because the cashew cultivation is done mainly to produce cashew nuts. About 90% of the cashew apples production is lost in the field after removing the nut. In this work, the use of clarified cashew apple juice as substrate for microbial cultivation was investigated. The results showed that cashew apple juice is a good source of reducing sugars and can be used to grow Leuconostoc mesenteroides to produce high added value products such as dextran, lactic acid, mannitol and oligosaccharides.
The aim of this work was to select strains of Aspergillus niger for tannase production. Growth of colonies in plates with tannic acid-containing medium indicated their ability to synthesize tannase. Tannase activity was also measured in solid-state fermentation. A. niger 11T25A5 was the best tannase producer (67.5 U.g -1 /72 hours of fermentation).
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