Biochemical and spectroscopic characterization of the membrane-bound nitrate reductase from Marinobacter hydrocarbonoclasticus 617

J Biol Inorg Chem (2008) 13:1321–1333 DOI 10.1007/s00775-008-0416-1

Transimpedance amplifier for integrated SpO2 optic sensor

Dissertação para obtenção do Grau de Mestre em Engenharia Electrotécnica e de Computadores

A happiness index of human development

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Economics from the NOVA – School of Business and Economics

Pirólise de óleos vegetais de elevada acidez

Dissertação apresentada à Universidade Nova de Lisboa, Faculdade de Ciências e Tecnologia, para obtenção do Grau de Mestre em Energia e Bioenergia

A 1.2 V low noise amplifier with double feedback for high gain and low noise figure

Dissertação para obtenção do Grau de Mestre em Engenharia Eletrotécnica e de Computadores

A low-voltage RF-CMOS receiver front-end for a wireless fall detection microsystem

Dissertação para obtenção do Grau de Mestre em Engenharia Eletrotécnica e de Computadores, pela Universidade Nova de Ciências e Tecnologia

Rex musicus. Iconografia do salmo 80 nas bíblias francesas do século XIII

Revista do IHA, N.3 (2007),pp.130-151

CMOS indoor light energy harvesting system for wireless sensing applications

Dissertação para obtenção do Grau de Doutor em Engenharia Electrotécnica e de Computadores

Transimpedance amplifier for early detection of breast cancer

Breast cancer is the most common type of cancer worldwide. The effectiveness of its treatment depends on early stage detection, as well as on the accuracy of its diagnosis. Recently, diagnosis techniques have been submitted to relevant breakthroughs with the upcoming of Magnetic Resonance Imaging, Ultrasound Sonograms and Positron Emission Tomography (PET) scans, among others. The work presented here is focused on studying the application of a PET system to a Positron Emission Mammography (PEM) system. A PET/PEM system works under the principle that a scintillating crystal will detect a gamma-ray pulse, originated at the cancerous cells, converting it into a correspondent visible light pulse. The latter must then be converted into an electrical current pulse by means of a Photo- -Sensitive Device (PSD). After the PSD there must be a Transimpedance Amplifier (TIA) in order to convert the current pulse into a suitable output voltage, in a time period lower than 40 ns. In this Thesis, the PSD considered is a Silicon Photo-Multiplier (SiPM). The usage of this recently developed type of PSD is impracticable with the conventional TIA topologies, as it will be proven. Therefore, the usage of the Regulated Common-Gate (RCG) topology will be studied in the design of the amplifier. There will be also presented two RCG variations, comprising a noise response improvement and differential operation of the circuit. The mentioned topology will also be tested in a Radio-Frequency front-end, showing the versatility of the RCG. A study comprising a low-voltage self-biasing feedback TIA will also be shown. The proposed circuits will be simulated with standard CMOS technology (UMC 130 nm), using a 1.2 V power supply. A power consumption of 0.34 mW with a signal-to-noise ratio of 43 dB was achieved.

Simulação da secção de recuperação de solvente do processo de produção do PEAD

A presente dissertação foi realizada no âmbito de um estágio curricular no complexo petroquímico da Repsol Polímeros em Sines e teve como objectivo implementar uma simulação da secção de recuperação de solvente da unidade de produção de PEAD. A simulação foi realizada através do software Aspen Hysys (v. 7.3) e posteriormente validada, onde se verificou uma boa correspondência entre o comportamento simulado e o do processo industrial. Após validação, com o intuito de analisar a resposta do sistema a alterações processuais, foram elaborados dois casos de estudo: Alteração do comonómero para 1-hexeno e substituição do n-hexano para n-pentano como solvente. No primeiro caso de estudo foram encontrados problemas na purificação do solvente. A separação da mistura n-hexano/1-hexeno foi estudada por destilação convencional e extractiva (com adição de n-metil-2-pirrolidona). Por destilação convencional não foi possível separar completamente os dois compostos, mas foi conseguida a condição mínima requerida pelas limitações do processo, de um caudal de 10 ton/h de hexano na corrente de topo, juntamente com os 700 kg/h de comonómero, com uma coluna a operar a 110 kPa, com 130 pratos e cuja alimentação entrava no 5º andar. A destilação extractiva revelou-se o método mais eficaz, conseguindo-se separar completamente as duas espécies através de uma coluna de destilação com 10 pratos a 110 kPa com a alimentação e solvente a entrar respectivamente no 4º e 5º andar. Para remoção do agente extractivo, cada uma das correntes sofre outra destilação. No segundo caso de estudo verificou-se que a secção simulada com pentano apresenta temperaturas de operação inferiores, o que por um lado vai diminuir o consumo de vapor de média e de alta pressão, mas por outro aumenta a 47992% a utilização de brine. Desta forma, atendendo ao custo elevado desta utilidade, a substituição não apresenta clara vantagem energética ao processo.

Contribuição para o estudo das parasitoses em Portugal: Helmintas intestinais em crianças escolares do concelho de Palmela

Nos últimos anos, os trabalhos desenvolvidos na área da epidemiologia parasitária em Portugal são escassos. Assim, este trabalho teve como objectivo contribuir para um melhor conhecimento das helmintoses intestinais presentes em crianças escolares, em Portugal e relacionar a situação parasitária de cada indivíduo com os resultados dos inquéritos sobre comportamentos e condições de vida. Foi realizado um inquérito epidemiológico em duas escolas do Concelho de Palmela, abrangendo um universo de 223 crianças com idades compreendidas entre os 5 e os 12 anos, das quais 121 pertenciam ao sexo feminino e 102 ao sexo masculino. As escolas em estudo estão localizadas numa zona urbana (Escola de Palmela) com um total de 130 alunos e numa zona peri-urbana (Escola do Bairro Alentejano) com um total de 132. Para a pesquisa de ovos de parasitas intestinais nas amostras de fezes foram utilizados dois métodos: a técnica de Willis e o kit comercial - Easy-Copros, concentrador para parasitas intestinais. Todas as amostras do presente estudo foram negativas. A comparação dos resultados por nós obtidos com os relatados em publicações anteriores leva-nos a concluir que nos últimos anos tem ocorrido uma diminuição dos helmintas intestinais. Este facto, de acordo com os nossos dados, estará relacionado com uma melhoria das condições socioeconómicas das populações, uma rede de infra-estruturas de saneamento básico abrangente em parceria com os projectos desenvolvidos pelos Centros de Saúde, no âmbito da Saúde Escolar.

Mechanical characterization of aortas using 2D ultrasound elastography

Rupture of aortic aneurysms (AA) is a major cause of death in the Western world. Currently, clinical decision upon surgical intervention is based on the diameter of the aneurysm. However, this method is not fully adequate. Noninvasive assessment of the elastic properties of the arterial wall can be a better predictor for AA growth and rupture risk. The purpose of this study is to estimate mechanical properties of the aortic wall using in vitro inflation testing and 2D ultrasound (US) elastography, and investigate the performance of the proposed methodology for physiological conditions. Two different inflation experiments were performed on twelve porcine aortas: 1) a static experiment for a large pressure range (0 – 140 mmHg); 2) a dynamic experiment closely mimicking the in vivo hemodynamics at physiological pressures (70 – 130 mmHg). 2D raw radiofrequency (RF) US datasets were acquired for one longitudinal and two cross-sectional imaging planes, for both experiments. The RF-data were manually segmented and a 2D vessel wall displacement tracking algorithm was applied to obtain the aortic diameter–time behavior. The shear modulus G was estimated assuming a Neo-Hookean material model. In addition, an incremental study based on the static data was performed to: 1) investigate the changes in G for increasing mean arterial pressure (MAP), for a certain pressure difference (30, 40, 50 and 60 mmHg); 2) compare the results with those from the dynamic experiment, for the same pressure range. The resulting shear modulus G was 94 ± 16 kPa for the static experiment, which is in agreement with literature. A linear dependency on MAP was found for G, yet the effect of the pressure difference was negligible. The dynamic data revealed a G of 250 ± 20 kPa. For the same pressure range, the incremental shear modulus (Ginc) was 240 ± 39 kPa, which is in agreement with the former. In general, for all experiments, no significant differences in the values of G were found between different image planes. This study shows that 2D US elastography of aortas during inflation testing is feasible under controlled and physiological circumstances. In future studies, the in vivo, dynamic experiment should be repeated for a range of MAPs and pathological vessels should be examined. Furthermore, the use of more complex material models needs to be considered to describe the non-linear behavior of the vascular tissue.

EL PAISAJE Y LA TRANSICIÓN ENERGÉTICA: COMPARANDO EL SURGIMIENTO DE PAISAJES DE ENERGÍA EÓLICA EN FRANCIA, ALEMANIA Y PORTUGAL

Due to the global acceptance of the reality of global warming, ever more countries are in the process of implementing alternative energies such as wind power. In this article, we focus on the transformation of space as a consequence of these newly established alternative energy policies. Landscapes are the level at which political visions and policy decisions endorse (or not) their very materiality. We analyze the deployment of wind power in three European countries, France, Germany and Portugal through the lens of ethnographic landscape studies. We argue that the successful implementation of low carbon futures is highly dependent on the respective national cultures of administration as well as on local practices, initiatives and perceptions of space at the local level. In each of the countries under scrutiny, we analyze the way in which wind power and landscape issues are framed, we point at potential tensions and explore how these are overcome (or not) at the local level so as to give way for the emergence of (new) wind power landscapes. We compare the role played by landscape cultures, institutions or practices in the development and resolution of tensions over the deployment of wind energy.

ENERGÍA EÓLICA Y PAISAJES PROTEGIDOS: CONTROVERSIAS EN EL PARQUE NATURAL DE MONTESINHO

As one of the case studies developed under the international project “Eoliennes et paysage” we could follow the controversial issue of wind power and protected areas in the Montesinho Natural Park, Northeast Portugal, where the local populations demand the setting up of a wind farm in unproductive communal lands, aspiring to benefi t economically from it, while the preservationist claims against wind power within the protected area are sensed by them as an external and illegitimate interference in the communitarian management of a local heritage. Although wind power installation in Montesinho mountains is yet only a virtual possibility (facing hard administrative and technical barriers), this case study contributed to shed light into the kind of negotiations that are being promoted at local and regional levels, and how the present banning of wind power in the region due to conservation restrictions is reactivating ancient antagonisms.

A piezoelectric based energy harvester interface for a CMOS wireless sensor IC

In this thesis a piezoelectric energy harvesting system, responsible for regulating the power output of a piezoelectric transducer subjected to ambient vibration, is designed to power an RF receiver with a 6 mW power consump-tion. The electrical characterisation of the chosen piezoelectric transducer is the starting point of the design, which subsequently presents a full-bridge cross-coupled rectifier that rectifies the AC output of the transducer and a low-dropout regulator responsible for delivering a constant voltage system output of 0.6 V, with low voltage ripple, which represents the receiver’s required sup-ply voltage. The circuit is designed using CMOS 130 nm UMC technology, and the system presents an inductorless architecture, with reduced area and cost. The electrical simulations run for the complete circuit lead to the conclusion that the proposed piezoelectric energy harvesting system is a plausible solution to power the RF receiver, provided that the chosen transducer is subjected to moderate levels of vibration.