Production of ductile iron using ferrosilicon-magnesium master alloy in melt treatment is currently fraught with challenges bothering on cost and availability. In this study the suitability of cashew nut shells ash (CNSA) as a viable alternative to magnesium master alloys employed in the treatment of molten cast iron for enhanced mechanical properties was studied. The carbonized CNSA used varied from 2-10 wt. % to treat different heat batches; CA1-CA5 containing varied amount of CNSA, CaO and FeSi in the molten cast iron. The cast samples were subjected to both mechanical characterisation (tensile, hardness and impact) and microstructural analysis using Instron electromechanical machine, impact tester and scanning electron microscope (SEM) coupled with energy dispersive spectroscope (EDS). Results show that the 8 wt. % CNSA addition demonstrated the best mechanical properties comparable to ASTM A536 ferritic ductile cast iron. Specifically, the 8 wt. % CNSA cast samples exhibited 433 MPa tensile strength, 144HRC hardness and ductility of 14.7%. Contributions to improved mechanical properties may be attributed to the development of sufficient fractions of graphite nodules during melt treatment with CNSA. These outcomes are a boost both to the production of quality ductile irons and a cleaner environment. Keywords: Nodularisation, ductile-iron, cashew-nut, ferrosilicon-magnesium alloy, mechanical properties

Effective reduction and control of noise have continued to attract attention globally due to the adverse effects noise poses to human health, effective knowledge dissemination and desirable environmental tranquility. The use of natural and synthetic reinforced composites in noise pollution control is an emerging area of research. In this study, coal fly-ash in nanoparticles varied at 5 -25 wt. % was employed as reinforcement in the fabrication of epoxy resin composites. The composites were characterized both for noise reduction capability and mechanical properties necessary for a damage-free handling during installation. Results showed that samples of the composites at 15 wt. % exhibited the highest noise reduction coefficient (NRC) of 0.8072. This translates to 81% noise reduction capability if deployed in a facility and compares very well with that of conventional acoustical materials that are used in buildings and other facilities. The mechanical properties exhibited by the composite samples in terms of flexural strength (20.3 -43.7 MPa), impact energy (4.4 -4.8 J), and hardness (13.3 -15.3 HV) are sufficient for the intended area of application. Thus, the composite developed at 15 wt. % fly-ash addition is recommended for deployment in auditorium (lecture theatre), public library, hospital ward and hotels. These facilities have maximum recommended noise levels in the range of 35 -45 db. The composites are adjudged suitable for application as noise muffling materials in buildings and other facilities that are usually subjected to low mechanical system noise sources.