Metal matrix composites (MMCs) are materials in which metals are reinforced with other materials preferably of lower cost to improve their properties. In this present study, Brass /Coconut Shell Ash powder (CSAp) composites having 0%, 5%, 10% and 15% weight CSAp were fabricated by stir-casting method. The tensile strength of the MMCs is in the order 15% > 10% >5% > 0% of CSAp. Hardness of the MMCs increases slightly with increase in the percentage body weight of CSAp, in the order 15% > 10% >5% > 0% of CSAp. The highest impact energy of 61 J was obtained for 5% CSAp. However, significant improvement in tensile strength and hardness values was noticeable at the 15%. Scanning Electron Microscopy (SEM) analysis of the MMCs shows dendritic structures formation, the reinforcing particles (CSAp) are visible and clearly delineated in the microstructure. Hence, this study has established that reinforcing brass matrix with coconut shell ash particles can result in the production of low cost brass composites with enhanced tensile strength, hardness and impact energy values.
Contamination of soils by heavy metals has severely increased over the last few decades due to industrial wastes and human activities. Contaminated soils can constitute sources of health hazard to humans globally. However, there is paucity of information on the level of heavy metal concentration in the study area. This study therefore made a pioneering effort in investigating the concentration of selected heavy metals (Cd, Cu, Pb, Zn and Fe) in soils around a scrap metal recycling company in Ile-Ife, Osun State, Nigeria. Thirty soil samples and solid wastes were collected from four sides of the scrap metal recycling company. The samples were air-dried, digested using standard method and analyzed for the selected heavy metals using a flame atomic absorption spectrometer. Results of the Atomic Absorption Spectrophotometric (AAS) analysis revealed that for heavy metals, the concentrations in the soils were below the background levels and permissible limits recommended for soils in some countries. The value of the mean concentration of the analyzed heavy metals in the soils around the scrap metal recycling company ranged from 0.0040 – 0.0140 mg/kg for Cd, 0.061 – 0.108 mg/kg for Fe, 0.037 – 0.047 mg/kg for Cu, 0.003 – 0.0064 mg/kg for Pb and 0.019 – 0.121 mg/kg for Zn. The results from the study indicated that the concentrations of heavy metals around the scrap metal recycling company did not appear to be of serious concern. The concentrations of all the heavy metals were below the background level proposed by the World Health Organization (WHO) residential soil standards.
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