Simulation of rectifier voltage malfunction on OWECS, four-level converter, HVDC light link: Smart grid context tool

This paper presents a model for the simulation of an offshore wind system having a rectifier input voltage malfunction at one phase. The offshore wind system model comprises a variable-speed wind turbine supported on a floating platform, equipped with a permanent magnet synchronous generator using full-power four-level neutral point clamped converter. The link from the offshore floating platform to the onshore electrical grid is done through a light high voltage direct current submarine cable. The drive train is modeled by a three-mass model. Considerations about the smart grid context are offered for the use of the model in such a context. The rectifier voltage malfunction domino effect is presented as a case study to show capabilities of the model. (C) 2015 Elsevier Ltd. All rights reserved.

Light memory function in a double pin SiC device

A double pi'npin heterostructure based on amorphous SiC has a non linear spectral gain which is a function of the signal wavelength that impinges on its front or back surface. An impulse of a configurable length and amplitude is applied to a 390 nm LED which illuminates one of the sensor surfaces, followed by a time period without any illumination after which an input signal with a different wavelength is impinged upon the front surface. Results show that the intensity and duration of the impulse illumination of the surfaces influences the sensor's response with different output for the same input signal. This paper studies this effect and proposes an application as a short term light memory. (C) 2015 Elsevier B.V. All rights reserved.

Partitura de luz: a representação criativa como perspectiva educacional

Este projecto de investigação teve como objectivo avaliar - através de uma série de workshops orientados pela mestranda no Centro Cultural de Belém em Abril de 2012 - o impacto da utilização de notação musical não-convencional num contexto não escolar. Traçando possíveis paralelos com o ensino especializado da música, propuseram-se metodologias de aprendizagem que permitissem a introdução da notação, de forma inovadora, no referido contexto escolar. O processo de investigação baseou-se em observação directa, na análise dos questionários preenchidos pelos participantes dos workshops e na observação e análise das gravações em vídeo que documentaram o processo artístico, pedagógico e de investigação. Numa sala escura, 6 retroprojectores projectaram uma Partitura de Luz. Entre crianças e adultos, 120 participantes (não-músicos) criaram empiricamente as suas composições, moldando o som em função da forma e a forma em função do som. O resultado foi compensador: a criação de condições favoráveis ao desenvolvimento máximo da expressão criativa individual ou colectiva dos participantes - através da utilização irrestrita de símbolos, imagens, objectos e matérias - culminou num efectivo estabelecimento de correspondência musical, a partir de recursos vocais. Este projecto, “Partitura de Luz”, foi uma oportunidade de relacionar a vertente artística – musical, plástica e gráfica - com a vertente humana: pedagógica e social.

CMOS indoor light energy harvesting system for wireless sensing applications

This book discusses in detail the CMOS implementation of energy harvesting. The authors describe an integrated, indoor light energy harvesting system, based on a controller circuit that dynamically and automatically adjusts its operation to meet the actual light circumstances of the environment where the system is placed. The system is intended to power a sensor node, enabling an autonomous wireless sensor network (WSN). Although designed to cope with indoor light levels, the system is also able to work with higher levels, making it an all-round light energy harvesting system. The discussion includes experimental data obtained from an integrated manufactured prototype, which in conjunction with a photovoltaic (PV) cell, serves as a proof of concept of the desired energy harvesting system. © 2016 Springer International Publishing. All rights are reserved.