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Low-power wireless sensing-based networks suffer from many constraints and challenges. In this research work, efficient power source has been designed to provide the need of energy for the Wireless Sensor Networks (WSNs) and Wireless Body Area Networks (WBANs). The energy sources are the main challenge and constraint these wireless networks applications. This paper discusses recent researcher's works which considered the energy constraints of the WSN and WMSN with their proposed security techniques. The main idea of this presented work is the energy harvesting through extracting the electrical energy from the audio/acoustic signal/energy, this utilized audio/acoustic source in this scenario is the disk jockey. To maximize the produced power from the proposed acoustic energy harvesting Piezo-based several parameters is studied. The parameters are considered in this research work are the method of Piezo-transducers connections, the distance of sound source, the sound intensity variation and the sound concentrating tube length. These tubes are mounted on slim diaphragm two maximize the energy harvesting. The piezoelectric transducer array scenario is designed using four piezoelectric transducers utilizing different connect ion methods, series, parallel and in hybrid. Several practically experiments are performed on the presented different scenarios to evaluate the proposed energy harvesting efficiency. These experiments reveal that the superiority of the proposed acoustic energy harvesting technique with low power complexity wireless networks and suitable with the different presented scenarios. [ABSTRACT FROM AUTHOR]

Objective: Pediatric patients with skull defects larger than available sources for splitting bicortical bone have limited options for autogenous cortical bone cranioplasty. Piezoelectric instruments allow donor bone to be chosen based on the best possible contour rather than the presence of bicortical bone. We present the use of piezoelectric technology to split thin unicortical calvarium for autogenous cranioplasty in a series of pediatric patients. Design: Retrospective review of a series of pediatric patients requiring reconstruction for skull defects. Patients/Intervention: Our series included a 2-year-old with a parietal skull tumor and resultant 3 x 3-cm defect after craniectomy, a 2-year-old with a 3 × 3-cm defect after excision of an occipital skull tumor, a 10-year-old with a 4 × 5-cm skull defect after excision of an occipital skull tumor, and a 13-year-old who suffered a gunshot to the forehead with a 12 × 7-cm frontal skull defect. We used a piezoelectric saw to precisely and safely split unicortical and bicortical cranium that ranged from 1 to 3 mm in thickness. The inner layer was used to reconstruct the donor site; whereas, the outer layer was used for the craniectomy defect. Conclusion: The piezoelectric saw allows unicortical bone to be split and used for cortical bone cranioplasty. This technology allows choice of donor site based on the best contour rather than the presence of bicortical bone. This technique expands the possibilities of autogenous cranioplasty and enables primary repair of cranial defects that would otherwise require secondary cranioplasty with remote donor sites, foreign materials, or unstable particulate cranioplasty. [ABSTRACT FROM AUTHOR]