Evolutionary in Solid State Recycling Techniques of Aluminium: A review

AbstractThis paper provides an intensive review on past and current research works in solid state recycling of aluminium and its alloys. The review relates the extrudates quality of the solid state recycled aluminium to certain aspects noted as chips preparation, reinforced materials addition, die geometry, processing parameters, and performance of miscellaneous solid state recycling techniques. Finally, concluding remarks underline challenges for aluminium recycling by the solid state and also highlight the potential future work on making the method as a promising alternative for sustainable manufacturing and hence technologically feasible for industrial implementation

Recycling aluminium AA6061 chips with reinforced boron carbide (B4C) and zirconia (ZrO2) particles via hot extrusion

Compared to the recycling process by remelting, hot extrusion significantly reduces the energy consumption and CO2 emission and ensures good mechanical and microstructural properties. This study investigates the effects of reinforcing aluminium AA6061 chips with mixed boron carbide (B4C) and zirconia (ZrO2) particles by employing a design of experiment (DOE) under 550 °C processing temperature and three hours preheating time. The findings showed that compressive strength (CS) and hardness increased with up to 5% added particles, and beyond 5%, the yielded values decreased because of materials agglomeration. However, the decreasing density was dependent on the addition of ZrO2 particles. The distribution of particles with different volume fractions of mixed particles was investigated by employing SEM, AFM, and EDS tests. Thus, the process can produce a net shape structure that utilises material-bonding consolidation to provide sufficient support to reuse the recovered materials in engineering applications, such as in the automotive industry

Vasorelaxant activity of indole alkaloids from Tabernaemontana dichotoma.

The aim of this study was to search for bioactive natural products from medicinal plants targeting vasorelaxant activity and we found the methanol extract from bark of Tabernaemontana dichotoma showed vasorelaxant activity on rat aorta. We isolated eight indole alkaloids including 10-methoxyalstonerine (1), a new macroline type indole alkaloid, from bark of T. dichotoma. These were respectively identified as 10-methoxyaffinisine (2), lochnerine (3), cathafoline (4), (−)-alstonerine (5), 19,20-dehydro-10-methoxytalcarpine (6), alstonisine (7), and alstonal (8) based on spectroscopic analysis. Among them, sarpagine type (2 and 3), akuammiline type (4), and macroline oxindole type (7 and 8) showed potent vasorelaxant activity. Mechanism of action on vasorelaxant activity of 10-methoxyaffinisine (2), cathafoline (4), and alstonisine (7) was clarified. Effects of 10-methoxyaffinisine (2), cathafoline (4), and alstonisine (7) were partially mediated the NO release from endothelial cells. Furthermore, 10-methoxyaffinisine (2) and alstonisine (7) attribute to the inhibitory effect of VDC and ROC, and cathafoline (4) have inhibitory effect on Ca2+ influx via ROC. In addition, 10-methoxyaffinisine (2) as a major compound from bark of T. dichotoma showed hypotensive effect on normotensive rats in vivo