Plates of AZ91 magnesium alloy were butt-welded using a CO2 laser. The non-equilibrium solidification of the laser-melted metal caused fragmentation of the weld microstructure as well as the supersaturation of a solid solution of aluminium in magnesium, which enabled the T5 ageing of the weld. The weld proved to be a mechanically stable part of the joint; all the tensile-tested specimens, both as-welded and post-weld T5 aged, fractured outside it. During the ageing of the supersaturated joint, which involved heat treating it to the T6 condition, the weld was the region where discontinuous precipitation was observed and this was the location of fracture in the tensile specimens. Thus, the strength properties of welded, supersaturated and aged AZ91 were much worse than when the non-welded material was T6 tempered.

Wireless body area network (WBAN) has evolved from Wireless personal area network (WPAN), a prominent area of research with vast applications in last decade. In WBAN, various wirelessly interconnected body node (BN) are implanted in or around the human body. Also due to advancement in technology a miniature low power device/BN is developed. The main challenge in WBAN body node is to maintain finite size of battery as well as to increase its capacity. Hence this issue can be resolved by using energy harvesting. Generally researchers have used piezoelectric, electromagnetic or solar harvester only. But, in this research energy harvesting using the hybrid optimization of Piezoelectric and Peltier sensors by controlling on-off timing of body nodes is introduced. A hybrid optimized algorithm is developed using MATLAB 2015b platform and extensive simulation is performed considering four different human gestures (relaxing, walking, running and fast running) which in turn improves overall Quality of Service (QoS) including average (packet loss, end to end delay, throughput) and overall detection efficiency.