In this study, silicon carbide (SiC) reinforced lead-free solder (SAC305) was prepared by the powder metallurgy method. In this method SAC305 powder and SiC powder were milled, compressed and sintered to prepare composite solder. The composite solders were characterized by optical and scanning electron microscopy for the microstructural investigation and mechanical test. Addition of 1.5 wt. % and 2 wt. % ceramic reinforcement to the composite increased compressive strengths and microhardness up to 38% and 68% compared to those of the monolithic sample. In addition, the ceramic particles caused an up to 55% decrease in the wetting angle between the substrate and the composite solder and porosity was always increased with increase of SiC particles.
This paper proposes an active noise control (ANC) application to attenuate siren noise for the patient lying inside ambulance with no sound proofing. From the point of cost effectiveness, a local ANC system based on feedforward scheme is considered. Further, to handle the limitation of limited Zone of Silence (ZoS), the ANC based on virtual sensing is explored. The simulations are done in MATLAB for the recorded ambulance siren noise signal. The results indicate that ANC can be an effective solution for creating a silent environment for the patient.