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Highlights: [•] The possibility of monitoring the mechanical stress over time in prosthesis is presented. [•] High sensitive silicon thin-film piezoresistive sensors were applied. [•] Their performance is appropriate to be implemented in smart prosthesis applications. [Copyright &y& Elsevier]

Abstract: Ultrasound transducers are typically based on piezoelectric materials, due to their good response at high frequencies. Depending on the application, ceramics, polymers and composite materials can be used. In this work, an optimization study of ultrasound transducers for underwater communications is addressed, focusing on a piston type emitter transducer operating in thickness mode (d 33). The piston is constituted by an active element disk with optimized dimensions. It is discussed how the acoustic impedance, thickness, resonance frequency and structure affect the transducer performance. This work allows a better understanding of the emitter transducer characteristics allowing reaching the optimum point of operation for specific applications. Focusing on underwater communication, the acoustic channel is defined and the transducer is optimized by finite element computer simulations. The results were compared with experimental tests, which show that four-layer structures increase up to 16dB in performance versus single-layer. [Copyright &y& Elsevier]

Highlights: [•] Electrospun fibers of PVDF (PVDF-TrFE) and composites with BaTiO3 have been prepared. [•] The influence of the processing parameters on fiber size and distribution is determined. [•] The energy harvesting of the fibers has been evaluated. [•] Power outputs up to 25μW have been obtained. [•] The obtained values are among the largest found in the literature. [Copyright &y& Elsevier]