Microstructure and rheological behavior of hypereutectic semi-solid Al–Si alloy under low shear rates compression test

Permanent mold cast cylindrical samples were reprocessed to form semi-solid billets of A390 Al–Si alloy, employing a thixocasting method. The billets were reheated to predetermined mushy zone temperatures and held isothermally during parallel plate compression tests. The deformation behavior of the billets was measured at different applied pressures, and fraction solids determined by the preheating temperature. The calculated viscosities confirmed pseudoplastic behavior of the semi-solid alloys and were correlated to the solid fraction and shear rate to illustrate the effect of metallurgical and process parameters on the viscosity and the consequent rheological behavior of these alloys.     

Influence of urea, isopropanol, and propylene glycol on rutin in vitro release from cosmetic semisolid systems estimated by factorial design

Rutin, one of the major flavonoids found in an assortment of plants, was reported to act as a sun protection factor booster with high anti-UVA defense, antioxidant, antiaging, and anticellulite, by improvement of the cutaneous microcirculation. This research work aimed at evaluating the rutin in vitro release from semisolid systems, in vertical diffusion cells, containing urea, isopropanol and propylene glycol, associated or not, according to the factorial design with two levels with center point. Urea (alone and in association with isopropanol and propylene glycol) and isopropanol (alone and in association with propylene glycol) influenced significant and negatively rutin liberation in diverse parameters: flux (microg/cm(2).h); apparent permeability coefficient (cm/h); rutin amount released (microg/cm(2)); and liberation enhancement factor. In accordance with the results, the presence of propylene glycol 5.0% (wt/wt) presented statistically favorable to promote rutin release from this semisolid system with flux = 105.12 +/- 8.59 microg/cm(2).h; apparent permeability coefficient = 7.01 +/- 0.572 cm/h; rutin amount released = 648.80 +/- 53.01 microg/cm(2); and liberation enhancement factor = 1.21 +/- 0.07.     

High temperature fatigue of nickel-base superalloys – A review with special emphasis on deformation modes and oxidation

Low cycle fatigue, high cycle fatigue, fatigue crack propagation and thermo-mechanical fatigue in Ni-base superalloys are reviewed in terms of fundamental deformation mechanisms, environmental effects, and interactions between environment and deformation mode. These factors are related to the chemical composition and underlying microstructure for all currently-used product forms (i.e. powder metallurgy, wrought, conventionally cast and single crystal). The basic principles that are developed are used to show how both intrinsic and extrinsic variables can be manipulated to control fatigue behaviour and as a guide for formulation of engineering life prediction models.     

Unraveling the effect of mixed charge carrier on the electrical conductivity in MAPbBr3 perovskite due to ions incorporation

Journal of Materials Science: Materials in Electronics - We have investigated the role of H+, Bi3+, and Sb3+ ions incorporation on the structural, morphological, optical, and transport properties...