Fibre-reinforced polymer strengthenir

The use of fiber-reinforced polymer (FRP) shear strengthening systems for the strength enhancement of existing reinforced concrete structures is discussed. An experimental and analytical research programme is under way to investigate the performance of bonded passive and unbonded prestressed FRP shear systems, and to quantify the effect of the load history on the strengthed behavior. Non-linear finite-element analysis are being developed to model the strengthed behavior. The results will provide insight into the optimum system parameters and contribute to the formulation of design guidance for advanced FRP strengthing strategies.

Phase separation induced by Au catalysts in ternary InGaAs nanowires.

We report a novel phase separation phenomenon observed in the growth of ternary In(x)Ga(1-x)As nanowires by metalorganic chemical vapor deposition. A spontaneous formation of core-shell nanowires is investigated by cross-sectional transmission electron microscopy, revealing the compositional complexity within the ternary nanowires. It has been found that for In(x)Ga(1-x)As nanowires high precursor flow rates generate ternary In(x)Ga(1-x)As cores with In-rich shells, while low precursor flow rates produce binary GaAs cores with ternary In(x)Ga(1-x)As shells. First-principle calculations combined with thermodynamic considerations suggest that this phenomenon is due to competitive alloying of different group-III elements with Au catalysts, and variations in elemental concentrations of group-III materials in the catalyst under different precursor flow rates. This study shows that precursor flow rates are critical factors for manipulating Au catalysts to produce nanowires of desired composition.