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This study presents the fabrication and comparative assessment of biodegradation and biocompatibility behaviors of pure Mg, Mg/HA (Hydroxyapatite), Mg-Zn/HA, and Mg-Sn/HA composites with fixed 5 wt% HA and 1 wt% each of Zn and Sn, using novel ultrasonic-assisted rheo casting technology. Characterization techniques, including X-ray diffractometry and scanning electron microscopy integrated with energy dispersive spectroscopy, were employed to analyze phase formation, surface morphology, and elemental composition. Microhardness tests were conducted to assess indentation resistance, while in vitro corrosion performance was evaluated in simulated bodily fluid to compare degradation behavior. Results indicate a uniform distribution of reinforced particles within the matrix with minimal casting defects. Intermetallic phases MgZn and Mg2Sn precipitated along grain boundaries in Mg-Zn/HA and Mg-Sn/HA composites. The Mg-Sn/HA composite exhibited peak microhardness (94.8 HV) due to precipitation strengthening. In contrast, Mg-Zn/HA samples showed a low degradation rate (0.19 mm/yr) and H2gas evolution rate (0.035 ml/mm2), attributed to uniform distribution of secondary phases and fine grains that mitigate galvanic cell formation and control degradation. Cell viability assay results demonstrated that Mg-Zn/HA composite outperformed all other samples, showing a 94% relative cell growth rate of osteosarcoma MG-63 cells after 2 h of incubation, attributed to strong apatite formation (rich in Ca and P) on the surface post-immersion, promoting cell proliferation.

In this work, palm oil biodiesel (POBD100) with a cyclo-octanol additive was employed in a constant speed diesel engine, and its effects on engine combustion, emission, and performance were studied. The biodiesel produced from palm oil by the conventional transesterification process, sodium hydroxide, and methanol were involved in the conversion of oil into biodiesel. The five fuels evaluated were neat palm oil biodiesel (POBD100), octanol blended with palm oil biodiesel by 10% volume (POBD90O10), octanol blended with palm oil biodiesel by 20% volume (POBD80O20), octanol blended with palm oil biodiesel by 30% volume (POBD70O30), and petroleum diesel. The experimental results revealed that with the increased octanol fraction, the combustion was smooth. All the octanol and biodiesel blends provide earlier combustion when compared to neat palm oil biodiesel which leads to higher thermal efficiency, lower fuel consumption, lower peak pressure, and shorter ignition delay. All the emissions are reduced by the addition of cyclo-octanol in palm oil biodiesel in all loads owing to the higher oxygen concentration of air/fuel mixtures and improved atomization. Based on the outcome of this study, palm oil biodiesel and cyclo-octanol blends can be employed as a potential alternative fuel for existing unmodified diesel engines owing to its improved combustion, emission, and performance characteristics.