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The purpose of this paper is to investigate the degree of improvement in mechanical properties of aluminum alloy (AA6063) after processing with equal channel angular extrusion (ECAE) using four environmentally benign lubricants.

Aluminum (Al) 6063 bar was annealed at 350°C for 1 hour, machined and cut to billets measuring 14 × 14 × 44 mm3. These specimens for extrusions were machined to the specified dimension to a visibly good finish. The billets were extruded through ECAE die of 14 × 14 mm2 channel cross-section area; the channel angle was 120°; and the angle of the outer arc of the channels was 30°. The punch and container used for the experiment were made of tool steel alloy AISI D2, and were chromium-coated and polished. Four lubricants such as palm, olive, coconut and groundnut oils were used in this study.

The yield, ultimate tensile strengths (UTS) and the ductility of the material ECAEed with palm oil as lubricant, which gave the least extrusion pressure, produces the maximum yield, UTS and ductility, followed by groundnut oil and coconut oil, while olive oil gave the least yield strength, (UTS) and ductility. However, palm oil and olive oil have better load reduction than other lubricants. Furthermore, from the hardness results, though scattered, all of the points at the tensile strained side of the extrudate lie within a reasonably narrow band, suggesting a high degree of homogeneity and greater hardness value within the rod than the compressive side after being ECAEed.

It is shown in the paper that all the lubricants tested greatly enhanced mechanical properties of Al 6063 and can effectively replace the petroleum-based lubricants used in forging operations.

Moringa oleifera (MO) is a herbal remedy that is rich in essential amino acids and phytochemicals in the leaves, seeds and pods. It is becoming a famous food in various ethnic groups, and the consumption is increasing worldwide. However, there is no safety profile of the hydroalcoholic MO leaf extracts, or documented teratogenicity aspect. This study was sought to compare the antioxidant activity and the teratogenicity of hydroalcoholic MO leaf extracts in the zebrafish embryo.

MO leaves were extracted with aqueous alcohols (ethanol or methanol: water, 80:20 v/v) using the Soxhlet method. The antioxidant capacity was determined using DPPH assay. The concentrations of extracts ranging from 3 to 1,000 µg/mL were used to examine the toxicity and teratogenicity on the zebrafish embryo.

Both hydroalcoholic MO leaf extracts were positive for alkaloids, terpenoids, steroids, tannins, flavonoids, phenols, coumarins, quinones and glycosides, except saponins only absent in aqueous methanol extract. The antioxidant capacity based on lC₅₀, was 15.92 ± 3.62 mg/mL for aqueous methanolic and 25.28 ± 2.89 mg/mL for aqueous ethanolic extract. For acute toxicity, the aqueous methanolic extract has lower LC₅₀ (163.87 ± 12.88 µg/mL) compared to aqueous ethanolic extract (337.48 ± 30.04 µg/mL). The embryo treated with aqueous methanolic extract showed phenotypic defect but not on the aqueous ethanolic extract.

This study suggests that aqueous methanol of MO leaves extract has better antioxidant capacity compared to ethanol, and ethanolic leaf extract is safer (higher LC50 and no teratogenicity) than methanolic extract.