This work presents an innovative technique to enhance the performance of the Savonius wind turbine. The new technique is based on introducing an upstream deflector and downstream baffle. The shape and location of both devices are optimized using a genetic algorithm. The performance of the turbine with the optimized devices is compared with the single Savonius turbine performance. The study employs the finite volume solver (ANSYS-FLUENT) to solve unsteady Reynolds Averaged Navier–Stokes equations and turbulence model equations. The optimized configuration results in much higher power coefficient than the Savonius turbine. The average peak power coefficient using both deflector and baffle is 0.47 compared to 0.24 of the Savonius turbine. The peak power coefficient of the turbine corresponds to a speed ratio close to unity. This improved performance is attributed to the favorable aerodynamic interaction between the turbine and the downstream baffle which accelerates the flow around the rotor and generates larger turning torque. The baffle generates a jet effect on the advancing bucket and accelerates the flow behind the bucket creating a large zone of negative pressure and thereby increases the driving torque. Furthermore, the upstream deflector (also called shield or curtain) produces a shield for the returning bucket of the turbine which diminishes the adverse effect associated with the returning bucket on the aerodynamic torque of the turbine. This remarkable improvement of turbine performance will encourage the future application of the Savonius wind turbine in small power applications of wind energy.

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Since most plastics are not biodegradable, plastic recycling is the main part of global efforts to reduce plastic in the waste stream. Sorting of plastics imposes lots of difficulties which can be avoided by introducing plastic blends. This paper starts by reviewing the recent attempts to study plastic blends. Accordingly, the purpose of this study is to analyze experimental results and apply statistical measures using ANOVA to study the effect of increasing the waste ratio that contains both waste polystyrene and polypropylene on the mechanical properties of pure polystyrene when injected at different temperatures. Cost is taken as a response factor to analyze whether the degradation of mechanical properties is justified by a decrease in cost. As expected, cost dramatically decreases with increasing the waste ratio at any temperature. Increasing the waste ratio resulted in better mechanical properties with a maximum at a 30% waste ratio at 200 C and 220 C. This paper ends with a multiobjective optimization analysis that helps decision-makers optimize the properties needed of the studied plastic blend by controlling both the temperature and waste ratio.

Emulsion polymerisation of vinyl acetate (VAc) and vinyl ester of versatic acid (VEOVA 10) was carried out using different feed composition ratios. The copolymer emulsion was characterised by measuring the morphological properties (average particle diameter, D) by using the transmission electron microscope (TEM); minimum film forming temperature (MFFT) and filtration residue (ppm). The results of the study indicate that the average particle diameter of emulsion (D) decreases with the increase of the amount of VEOVA 10 content (and subsequently decreases the amount of VAc), also the ppm and the MFFT is decreased. These results were illustrated using response surface methodology and contour plots. In this paper, the economic production of VAc and VEOVA 10 emulsion polymer was studied to ensure the best performance of all properties at minimum cost utilising multiobjective optimisation methodology.Keywords: emulsion polymerisation; vinyl acetate; VAc; vinyl ester of versatic acid; VEOVA 10; factorial design; response surface methodology; design expert software. 90 I. A. Sabbah et al.

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