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Browsing by Author "Martins, M. S."

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  • High frequency wide beam PVDF ultrasonic projector for underwater communications
    Publication . Martins, M. S.; Barardo, C.; Matos, T.; Gonçalves, L. M.; Cabral, J.; Silva, António; Jesus, Sergio
    This work describes the development and characterization of a wide beam and wideband ultrasonic transducer, designed as an emitter for underwater communications up to 1.5 MHz. The active element being used is composed of two layers of 110 mu m PVDF (Polyvinylidene fluoride) film, with NiCu electrodes. The transducer has a semicircular shape with a diameter of 15 cm. Pool trials show a transmitting voltage response of approximately 150 dB re mu Pa/V @ 1m from 750kHz to 1MHz and higher than 130 dB re mu Pa/V @ 1m between 250kHz and 1.5MHz. At 1 MHz, when excited with 12V, the transducer has a power consumption of 37.5 mW.
    2017Conference object Restricted access Show more
  • Network nodes for ocean data exchange through submarine fiber optic cable repeaters
    Publication . Martins, M. S.; Cruz, Nuno A.; Silva, António; Ferreira, Bruno; Zabel, Fred; Matos, Tiago; Jesus, Sergio; Pinto, André; Pereira, Eduardo; Matos, Aníbal; Faria, Carlos; Tieppo, Marcos; Goncalves, L. M.; Rocha, João; Faria, João
    As humanity progresses and globalization advances, humanized environment and associated systems increase in complexity and size. In earth systems, oceans represent an essential element of equalization and normal functioning. Ocean-atmospheric interactions are nowadays believed to be at the heart of all earth vital signs and climatic behaviours, and therefore are essential to accurate monitoring and understanding of earth systems. The work presented is a preliminary result of the K2D- Knowledge and Data from the Deep to Space, project which addresses the challenge of creating underwater network nodes to provide power and communication to land through the submarine fiber optic cable repeaters. The N2ODE system will consist of a set of subsystems that will allow continuous monitoring and interaction with fixed and mobile underwater devices.
    2022Other Restricted access Show more