In this study, open cell 25 % antimony-lead alloy foams are fabricated for possible use to lighten thick plates of lead-acid batteries. A new inexpensive and simple variant of the salt replication process is developed and explored. Different morphology and shapes have been successfully obtained with “excess salt replication” method (abbreviated as ESR method). Best porosity of about 68 % is obtained with salt particles size of about 3 mm. SEM and EDXS investigation of the composite salt/antimony alloy before NaCl leaching revealed the presence of the lead oxides microfilm coating cell walls and becoming lead carbonates after salt removal. Uniaxial compressive behaviour of the resulting cellular materials is studied for foams with porosities between 45 % and 70 %, and salt grain size ranging between 2.5 and 5 mm. A higher plateau stress is reached compared to the results obtained in the literature working on the aluminium foams. The reproducibility of the process is proved along samples.

In order to investigate a viable approach to fully exploit the wind speed, the present work investigates the application of a novel wind turbine consisting of dual doubly-fed induction generators (DFIG). The model can be further used to apply in areas where the winds are high to achieve high conversion efficiency in order to produce large electric power and increase the wind turbine capacity with an economy of hardware on the one hand, and to reduce the installation cost on the other. Furthermore, this model is always guarantees the continuity of power production because if one generator fails, the second generator will keep working until the broken one is repaired. The proposed model of the wind turbine based on dual doubly-fed induction generators (WT-dual-DFIG) were using the indirect field-oriented control (IFOC) was validated by wind turbine based on single doubly-fed induction generator (WT-single-DFIG) in MATLAB/Simulink. The results of simulation show that the simulated responses of the WT-dual-DFIG increased the power by a factor of about 14.3% compared to a WT-single-DFIG due to the use of a variable speed dual-DFIG. Finally, we can say that the WT-dual-DFIG model is strongly developed and could be applied in the coming years.

This study is devoted to the investigation of metallic foams based on tin-lead alloy (with 50% of tin content) by the liquid metal inltration process. Uniaxial tensile tests were performed at room temperature in order to study mechanical properties of foams of dierent relative density and cell size. The samples were concurrently characterized on a microscopic scale (metallography and hardness) in order to link the morphological and mechanical characteristics of the constitutive phases.