RESUMO
The microstructure evolution of 2196 Al-Li alloy during aging was investigated by microhardness test, transmission electron microscope (TEM) analysis and in situ resistivity measurement. The results showed that the resistivity of the 2196 Al-Li alloy during aging rapidly decreased during the first few hours, and then gradually increased after reaching the minimum value, which is temperature-dependent. The microstructure of the alloy was dominated by the δ' phase after aging at 160 °C for 2 h while the T1 phase could hardly be seen until it had been aged for 16 h. As the aging time went on, significant ripening appeared for the δ' phase while typical growth could be observed for the T1 phase. The increase in the resistivity of the 2196 Al-Li alloy during aging was attributed to the stronger electron scattering capacity of the T1 precipitation and the coupling effect between the T1 and δ' phases.
RESUMO
Generating or recycling water and resources from wastewater other than just treating wastewater is one of the most popular trends worldwide. Photosynthetic bacteria (PSB) wastewater treatment and resource recovery technology is one of the most potential methods. PSBs are non-toxic and contain lots of value-added products that can be utilized in the agricultural and food industries. They are effective to degrade pollutants and synthesize useful biomass, thus realizing wastewater treatment, bioresource production, and eliminating waste sludge. If all the nutrients in wastewaters could be bio-converted by PSB, then pollutant reductions and economic benefits would be achieved. This review paper firstly describes and summarizes this technology, including PSBs classification, metabolism, and the market application. The feasibility, technical procedures, bioreactors, pollutant removal, and bioresource production are also summarized, compared and evaluated. Issues that concern the advantages and industrialization of this technologies at the plant scale are also discussed.
