Design of a low-voltage CMOS RF receiver for energy harvesting sensor node

In this thesis a CMOS low-power and low-voltage RF receiver front-end is presented. The main objective is to design this RF receiver so that it can be powered by a piezoelectric energy harvesting power source, included in a Wireless Sensor Node application. For this type of applications the major requirements are: the low-power and low-voltage operation, the reduced area and cost and the simplicity of the architecture. The system key blocks are the LNA and the mixer, which are studied and optimized with greater detail, achieving a good linearity, a wideband operation and a reduced introduction of noise. A wideband balun LNA with noise and distortion cancelling is designed to work at a 0.6 V supply voltage, in conjunction with a double-balanced passive mixer and subsequent TIA block. The passive mixer operates in current mode, allowing a minimal introduction of voltage noise and a good linearity. The receiver analog front-end has a total voltage conversion gain of 31.5 dB, a 0.1 - 4.3 GHz bandwidth, an IIP3 value of -1.35 dBm, and a noise figure lower than 9 dB. The total power consumption is 1.9 mW and the die area is 305x134.5 m2, using a standard 130 nm CMOS technology.

Mobile image processing to support educational geometry games

The mobile IT era is here, it is still growing and expanding at a steady rate and, most of all, it is entertaining. Mobile devices are used for entertainment, whether social through the so-called social networks, or private through web browsing, video watching or gaming. Youngsters make heavy use of these devices, and even small children show impressive adaptability and skill. However not much attention is directed towards education, especially in the case of young children. Too much time is usually spent in games which only purpose is to keep children entertained, time that could be put to better use such as developing elementary geometric notions. Taking advantage of this pocket computer scenario, it is proposed an application geared towards small children in the 6 – 9 age group that allows them to consolidate knowledge regarding geometric shapes, forming a stepping stone that leads to some fundamental mathematical knowledge to be exercised later on. To achieve this goal, the application will detect simple geometric shapes like squares, circles and triangles using the device’s camera. The novelty of this application will be a core real-time detection system designed and developed from the ground up for mobile devices, taking into account their characteristic limitations such as reduced processing power, memory and battery. User feedback was be gathered, aggregated and studied to assess the educational factor of the application.

Relatório de atividade profissional e uma comparação do estudo da conservação de energia através de um sensor de movimento e de análise de vídeo

A apresentação do presente relatório visa a obtenção do Grau de Mestre em Ensino de Físico Química de acordo com o estabelecido no regulamento para Licenciados “Pré-Bolonha”, que abrange as licenciaturas de cinco anos com, pelo menos, cinco anos de experiência profissional. O percurso académico e profissional permitiram a aquisição de conhecimentos, tanto na Física como na Química, e um conjunto de aptidões como a capacidade organizacional, a capacidade de trabalhar em equipa e competências sociais. A constante vontade em atualizar conhecimentos e adquirir novas competências têm sido um incentivo para continuar a frequentar cursos de formação, seminários, workshops conferências dedicadas a esta área, assim como às do ensino. O presente trabalho é composto por duas partes. Na primeira parte, encontra-se a discrição da minha atividade profissional. Na segunda parte, encontra-se a apresentação detalhada do estudo da atividade laboratorial da bola saltitante por dois processos diferentes: utilizando um sensor de movimento e usando a análise de vídeo através do software Tracker.

Design, implementation, and performance of a distributed and scalable sensor system for critical distance measurements in the CMS detector at LHC

The “CMS Safety Closing Sensors System” (SCSS, or CSS for brevity) is a remote monitoring system design to control safety clearance and tight mechanical movements of parts of the CMS detector, especially during CMS assembly phases. We present the different systems that makes SCSS: its sensor technologies, the readout system, the data acquisition and control software. We also report on calibration and installation details, which determine the resolution and limits of the system. We present as well our experience from the operation of the system and the analysis of the data collected since 2008. Special emphasis is given to study positioning reproducibility during detector assembly and understanding how the magnetic fields influence the detector structure.

Desenvolvimento de um sensor de ibuprofeno em meio aquoso

A proteção dos recursos hídricos tem uma enorme importância ecológica, sendo a água um recurso indispensável à Vida e fundamental para o bem-estar de uma sociedade. Para isso, muitos dos poluentes que afetam a qualidade deste recurso natural são detetados e eliminados nas estações de tratamento de águas residuais. Porém, o impacto dos Produtos Farmacêuticos e de Cuidado Pessoal (PPCPs), usados à escala global, carece ainda da atenção necessária, dado que os meios técnicos atualmente disponíveis para detetar estes produtos são dispendiosos ou insuficientes. Dentro daquela classe de produtos, destaca-se o Ibuprofeno, uma vez que este composto, sendo lipossolúvel, tem a capacidade para se acumular nas gorduras dos seres vivos e, por conseguinte, persistir no meio-ambiente com efeitos nocivos. Para além desse facto, por diferentes vias de reação, o Ibuprofeno tem potencial para gerar produtos de carácter semelhante. No entanto, pouco esforços têm sido feitos no sentido de o detetar. Assim, pretendeu-se com este projeto desenvolver metodologias com vista à deteção de muito baixas concentrações (entre o nano e o picoMolar) daquele composto em meio aquoso. Foi utilizada a tecnologia de Língua Eletrónica por Espectroscopia de Impedância e, para tentar melhorar a sensibilidade do sensor à molécula-alvo, foram utilizados filmes finos à base de nanotubos de carbono e de diferentes polieletrólitos, preparados pela técnica de Camada-sobre-Camada (LbL, do inglês Layer-by-Layer). A caracterização destes filmes foi feita pela técnica Espectrofotometria na faixa dos Ultravioleta e Visível. Para além da análise de diferentes concentrações de Ibuprofeno, foram ainda analisadas soluções de Cloreto de Sódio, com o intuito de perceber se o sensor é versátil na deteção de outro tipo de compostos, sendo, então, o sal um composto barato e relevante neste âmbito, uma vez que a água na Natureza apresenta sempre alguma salinidade. O trabalho compreendeu ainda o desenvolvimento de um programa informático para automatizar o processo de aquisição dos dados espectrais de impedância, recolhidos pelo analisador HAMEG Programmable LCR Bridge HM8118, o que foi feito com sucesso. Posteriormente, os dados foram tratados pelo procedimento estatístico de Análise de Componentes Principais, que permitiu discriminar espacialmente e sequencialmente as diferentes concentrações dos compostos analisados.

Using an LED as a sensor and visible light communication device in a smart illumination system

The need for more efficient illumination systems has led to the proliferation of Solid-State Lighting (SSL) systems, which offer optimized power consumption. SSL systems are comprised of LED devices which are intrinsically fast devices and permit very fast light modulation. This, along with the congestion of the radio frequency spectrum has paved the path for the emergence of Visible Light Communication (VLC) systems. VLC uses free space to convey information by using light modulation. Notwithstanding, as VLC systems proliferate and cost competitiveness ensues, there are two important aspects to be considered. State-of-the-art VLC implementations use power demanding PAs, and thus it is important to investigate if regular, existent Switched-Mode Power Supply (SMPS) circuits can be adapted for VLC use. A 28 W buck regulator was implemented using a off-the-shelf LED Driver integrated circuit, using both series and parallel dimming techniques. Results show that optical clock frequencies up to 500 kHz are achievable without any major modification besides adequate component sizing. The use of an LED as a sensor was investigated, in a short-range, low-data-rate perspective. Results show successful communication in an LED-to-LED configuration, with enhanced range when using LED strings as sensors. Besides, LEDs present spectral selective sensitivity, which makes them good contenders for a multi-colour LED-to-LED system, such as in the use of RGB displays and lamps. Ultimately, the present work shows evidence that LEDs can be used as a dual-purpose device, enabling not only illumination, but also bi-directional data communication.

Desenvolvimento de um sensor para utilização em fixadores externos em ortopedia

Nesta dissertação é apresentada a metodologia adoptada no desenvolvimento de um sensor capaz de monitorizar a evolução da consolidação óssea proveniente de patologias tratadas com a utilização de aparelhos de fixação externa. O sensor tem como finalidade medir o deslocamento relativo entre os componentes do fixador externo que são proporcionais aos níveis de consolidação do osso. Surge como alternativa aos processos convencionais (raios-X, ultra-sons, etc.) que não possibilitam a detecção de imperfeições no processo de regeneração óssea numa fase precoce. Uma análise a vários materiais e geometrias revelaram que um sensor fabricado em latão e sob a forma de anel, após uma deformação de compressão de 4

Electrical characterization and modification of low dimensional oxide semiconductors for sensor applications

This work reviews the recent research on ion and UV irradiation of β-

Electro-Optical/Infrared sensor turret integration on an aircraft - structural im-pact on LOCKHEED MARTIN C-130H and design methodology

The growing need to patrol and survey large maritime and terrestrial areas increased the need to integrate external sensors on aircraft in order to accomplish those patrols at increasingly higher altitudes, longer range and not depending upon vehicle type. The main focus of this work is to elaborate a practical, simple, effective and efficient methodology for the aircraft modification procedure resulting from the integration of an Elec-tro-Optical/Infra-Red (EO/IR) turret through a support structure. The importance of the devel-opment of a good methodology relies on the correct management of project variables as time, available resources and project complexity. The key is to deliver a proper tool for a project de-sign team that will be used to create a solution that fulfils all technical, non-technical and certi-fication requirements present in this field of transportation. The created methodology is inde-pendent of two main inputs: sensor model and aircraft model definition, and therefore it is in-tended to deliver the results for different projects besides the one that was presented in this work as a case study. This particular case study presents the development of a structure support for FLIR STAR SAPHIRE III turret integration on the front lower fuselage bulkhead (radome) of the LOCKHEED MARTIN C-130 H. Development of the case study focuses on the study of local structural analysis through the use of Finite Element Method (FEM). Development of this Dissertation resulted in a cooperation between Faculty of Science and Technology - Universidade Nova de Lisboa and the company OGMA - Indústria Aeronáutica de Portugal

La Cène ou la figure du banquet comme image de crise morale chez Zeng Fanzhi

Les yeux et les masques sont prévalents dans les oeuvres du peintre chinois contemporain Zeng Fanzhi (né en 1964), comme métaphore du jeu de pouvoir qui oppose les individus à l’appareil social et politique. Son oeuvre La Cène, d’après Leonard de Vinci, est un exemple frappant de cette préoccupation. Cet essai examine l’utilisation par l’artiste de cette représentation occidentale d’une crise morale (une trahison qui mène à la mort du Christ) pour exprimer la dystopie qui marque la Chine contemporaine. L’interprétation par Zeng de l’oeuvre de Vinci témoigne d’une compréhension profonde de sa signification à la Renaissance comme conflit entre le pouvoir terrestre et spirituel, auquel il surimpose la fonction du banquet dans la culture chinoise comme lieu de lutte politique. Un nihilisme détaché imprègne ce travail, à l’instar de l’interprétation métaphorique du banquet de Platon par Søren Kierkegaard, In Vino Veritas.