A Banda da Guarda Nacional Republicana e os seus fagotistas

Dissertação de Mestrado para obtenção do grau de Mestre em Artes Musiciais

Esquistossomose mansoni em duas mesorregiões do Estado de Alagoas

No Brasil, índices elevados da esquistossomose mansônica correspondem, na grande maioria dos casos, à presença da espécie Biomphalaria glabrata, principal transmissora do Schistosoma mansoni, nas localidades endêmicas. Foi realizado estudo em 40 municípios endêmicos do Estado de Alagoas, com o objetivo de verificar a existência da espécie e sua importância na manutenção da esquistossomose nesse Estado. Desses municípios, 28 são pertencentes à mesorregião do leste Alagoano e 12 à mesorregião do Agreste Alagoano. Os moluscos procederam de diversos tipos de criadouros: riachos, córregos, valas, açudes, brejos e poços. As coletas foram realizadas no período de fevereiro de 1996 a dezembro de 1998. Para a identificação de Biomphalaria glabrata, foi efetuado o exame anatômico das partes moles, após remoção das conchas. A detecção de cercárias do Schistosoma mansoni foi realizada através da técnica de esmagamento, calculando-se o percentual de infecção. Em 32 (80%) dos municípios estudados foi encontrada Biomphalaria glabrata, seis deles apresentando moluscos infectados com cercárias do parasita. Penedo apresentou a maior (6,6%) taxa de infecção, seguindo-se Ibateguara (5,6%). Taxas menores foram observadas em Chã Preta (2,7%), em Murici (2,5%), Porto Real do Colégio (0,1%) e Igreja Nova (0,1%). O inquérito copro-parasitológico efetuado pela Fundação Nacional de Saúde em 1997, 1998/1999 e 2000, confirmou a importância da endemia nessas regiões do Estado.

Modelação analítica de coroas de jactos livres

O principal objectivo desta tese é demonstrar a importância dos jactos nas técnicas de combustão. Este trabalho inclui o estudo analítico de arranjos particulares de jactos circulares turbulentos, em situações não confinadas, dispostos em múltiplas coroas anelares, estando estas por sua vez dispostas em anel. Com isto pretende-se obter o caudal arrastado provocado pelos arranjos, o campo de velocidades longitudinal (teoria indutiva da turbulência de Reichardt), compreender a interacção entre jactos e garantir a melhor taxa de arrastamento. A escolha de situações não confinadas, deve-se ao facto de estas excluírem zonas de recirculação. A selecção de configurações é baseada nas que assegurem uma melhor taxa de arrastamento, configurações essas que podem variar no que respeita ao diâmetro dos injectores, no número de jactos e/ou coroas, e raio das coroas. Foi adoptado o estudo analítico, tendo em conta todas as variáveis das configurações, em vez da via numérica. Através da ferramenta Matlab, foi efectuada a integração numérica de forma a obter-se as taxas de arrastamento para diferentes planos paralelos à injecção. Os resultados mostram que uma interacção prematura entre jactos, nomeadamente em situações com um elevado número de jactos nas coroas, prejudica a taxa de arrastamento, devido aos jactos não se comportarem como jactos únicos livres por muito tempo.

Satisfação profissional dos médicos dentistas na utilização do cheque-dentista : um estudo exploratório no concelho de Lisboa

RESUMO - A satisfação profissional é um fenómeno amplamente estudado e esse interesse decorre da influência que a mesma pode exercer sobre o trabalhador, afetando a sua saúde, atitudes, comportamento profissional e social, com repercussões tanto para a sua vida privada como para as organizações. Considerando a tendência mundial de se aproximarem os perfis da profissão para um perfil único e de que a investigação sobre a satisfação profissional dos médicos dentistas em vários países estar presentemente a ser divulgada, seria importante avaliar a situação em Portugal para fins comparativos. O presente estudo teve como objetivo investigar o grau de satisfação profissional dos médicos dentistas na utilização do cheque-dentista no concelho de Lisboa, procurando estabelecer relações entre as diferentes dimensões da satisfação profissional e variáveis socioprofissionais. Um questionário de autopreenchimento foi enviado por e-mail para as clínicas onde os médicos dentistas trabalham, num total de 99 obtendo-se uma taxa de resposta de 24,2%. Verificou-se que em relação à satisfação profissional em geral nas várias dimensões questionadas, é a relação profissional/paciente que os médicos dentistas consideram como mais importante logo seguida da realização pessoal e profissional. Como menos importante os médicos dentistas referiram o status/prestígio e a segurança profissional. Já no campo da satisfação profissional no âmbito do cheque-dentista concluiu-se que mais próximo do grau de satisfeito se encontra a relação estabelecida com o paciente assim como a relação de trabalho com a equipa. No grau de satisfação mais baixo, de total insatisfação encontra-se o número de tratamentos que são permitidos efetuar em cada cheque-dentista e um último lugar encontrase o valor remuneratório do cheque-dentista. Comparando a satisfação profissional com o cheque-dentista entre géneros, verificou-se que apenas na dimensão do valor remuneratório do cheque-dentista existem diferenças estatisticamente significativas (p=0,026), sendo que o género feminino demonstra maior satisfação que o género masculino. O número de participantes não foi suficiente para que se possa generalizar os resultados para a população. É necessária a realização de mais estudos neste âmbito com um maior número de profissionais de forma a que os resultados sejam estatisticamente significativos.

FPGA field oriented control of an axial flux motor-in-wheel

This paper presents the design and the prototype implementation of a three-phase power inverter developed to drive a motor-in-wheel. The control system is implemented in a FPGA (Field Programmable Gate Array) device. The paper describes the Field Oriented Control (FOC) algorithm and the Space Vector Modulation (SVM) technique that were implemented. The control platform uses a Spartan-3E FPGA board, programmed with Verilog language. Simulation and experimental results are presented to validate the developed system operation under different load conditions. Finally are presented conclusions based on the experimental results.

Field oriented control of an axial flux permanent magnet synchronous motor for traction solutions

Electric Vehicles (EVs) are increasingly used nowadays, and different powertrain solutions can be adopted. This paper describes the control system of an axial flux Permanent Magnet Synchronous Motor (PMSM) for EVs powertrain. It is described the implemented Field Oriented Control (FOC) algorithm and the Space Vector Modulation (SVM) technique. Also, the mathematical model of the PMSM is presented. Both, simulation and experimental, results with different types of mechanical load are presented. The experimental results were obtained using a laboratory test bench. The obtained results are discussed.

A case study on the conversion of an internal combustion engine vehicle into an electric vehicle

This paper presents the conversion process of a traditional Internal Combustion Engine vehicle into an Electric Vehicle. The main constitutive elements of the Electric Vehicle are presented. The developed powertrain uses a three-phase inverter with Field Oriented Control and space vector modulation. The developed on-board batteries charging system can operate in Grid-to-Vehicle and Vehicle-to-Grid modes. The implemented prototypes were tested, and experimental results are presented. The assembly of these prototypes in the vehicle was made in accordance with the Portuguese legislation about vehicles conversion, and the main adopted solutions are presented.

Multifunctional converter to interface renewable energy sources and electric vehicles with the power grid in smart grids context

This paper proposes a multifunctional converter to interface renewable energy sources (e.g., solar photovoltaic panels) and electric vehicles (EVs) with the power grid in smart grids context. This multifunctional converter allows deliver energy from the solar photovoltaic panels to an EV or to the power grid, and exchange energy in bidirectional mode between the EV and the power grid. Using this multifunctional converter are not required multiple conversion stages, as occurs with the traditional solutions, where are necessary two power converters to integrate the solar photovoltaic system in the power grid and also two power converters to integrate an off-board EV battery charger in the power grid (dc-dc and dc-ac power converters in both cases). Taking into account that the energy provided (or delivered) from the power grid in each moment is function of the EV operation mode and also of the energy produced from the solar photovoltaic system, it is possible to define operation strategies and control algorithms in order to increase the energy efficiency of the global system and to improve the power quality of the electrical system. The proposed multifunctional converter allows the operation in four distinct cases: (a) Transfer of energy from the solar photovoltaic system to the power grid; (b) Transfer of energy from the solar photovoltaic system and from the EV to the power grid; (c) Transfer of energy from the solar photovoltaic system to the EV or to the power grid; (d) Transfer of energy between the EV and the power grid. Along the paper are described the system architecture and the control algorithms, and are also presented some computational simulation results for the four aforementioned cases. It is also presented a comparative analysis between the traditional and the proposed solution in terms of operation efficiency and estimated cost of implementation.

Predictive control of a current-source inverter for solar photovoltaic grid interface

Solar photovoltaic systems are an increasing option for electricity production, since they produce electrical energy from a clean renewable energy resource, and over the years, as a result of the research, their efficiency has been increasing. For the interface between the dc photovoltaic solar array and the ac electrical grid is necessary the use of an inverter (dc-ac converter), which should be optimized to extract the maximum power from the photovoltaic solar array. In this paper is presented a solution based on a current-source inverter (CSI) using continuous control set model predictive control (CCS-MPC). All the power circuits and respective control systems are described in detail along the paper and were tested and validated performing computer simulations. The paper shows the simulation results and are drawn several conclusions.

The impact of poor power quality in solar photovoltaic microgeneration: technical problems and losses of revenue

This paper presents a critical and quantitative analysis of the influence of the Power Quality in grid connected solar photovoltaic microgeneration installations. First are introduced the main regulations and legislation related with the solar photovoltaic microgeneration, in Portugal and Europe. Next are presented Power Quality monitoring results obtained from two residential solar photovoltaic installations located in the north of Portugal, and is explained how the Power Quality events affect the operation of these installations. Afterwards, it is described a methodology to estimate the energy production losses and the impact in the revenue caused by the abnormal operation of the electrical installation. This is done by comparing the amount of energy that was injected into the power grid with the theoretical value of energy that could be injected in normal conditions. The performed analysis shows that Power Quality severally affects the solar photovoltaic installations operation. The losses of revenue in the two monitored installations M1 and M2 are estimated in about 27% and 22%, respectively.

Three-phase current-source shunt active power filter with solar photovoltaic grid interface

This paper presents the proposal of a three phase current source shunt active power filter (CS-SAPF) with photovoltaic grid interface. The proposed system combines the compensation of reactive power and harmonics with the injection of energy from a solar photovoltaic array into the electrical power grid. The proposed equipment presents the advantage of giving good use to the current source inverter, even when the solar photovoltaic array is not producing energy. The paper describes the control system of the CS SAPF, the energy injection control strategy, and the current harmonics and power factor compensation strategy. Simulation results to assess the performance of the proposed system are also presented.

Evolution of the surface plasmon resonance of Au:TiO2 nanocomposite thin films with annealing temperature

This paper reports on the changes in the structural and morphological features occurring in a particular type of nanocomposite thin-film system, composed of Au nanoparticles (NPs) dispersed in a host TiO2 dielectric matrix. The structural and morphological changes, promoted by in-vacuum annealing experiments of the as-deposited thin films at different temperatures (ranging from 200 to 800 C), resulted in a well-known localized surface plasmon resonance (LSPR) phenomenon, which gave rise to a set of different optical responses that can be tailored for a wide number of applications, including those for optical-based sensors. The results show that the annealing experiments enabled a gradual increase of the mean grain size of the Au NPs (from 2 to 23 nm), and changes in their distributions and separations within the dielectric matrix. For higher annealing temperatures of the as-deposited films, a broad size distribution of Au NPs was found (sizes up to 100 nm). The structural conditions necessary to produce LSPR activity were found to occur for annealing experiments above 300 C, which corresponded to the crystallization of the gold NPs, with an average size strongly dependent on the annealing temperature itself. The main factor for the promotion of LSPR was the growth of gold NPs and their redistribution throughout the host matrix. On the other hand, the host matrix started to crystallize at an annealing temperature of about 500 C, which is an important parameter to explain the shift of the LSPR peak position to longer wavelengths, i.e. a red-shift.

Estudo do trabalho numa empresa de produção de pneus e implementação de ferramentas Lean

Dissertação de mestrado integrado em Engenharia e Gestão Industrial

Renewable energy system for an isolated micro grid

This paper presents the development of the power electronics needed for the interaction between the electrical generator of a wind turbine and an isolated ac micro grid. In this system there are basically two types of receptors for the energy produced by the wind turbine, which are the loads connected to the isolated micro grid and the batteries used to store energy. There are basically two states in which the system will work. One of the states is when there is enough wind power to supply the loads and the extra energy is used to charge the batteries. The other state is when there is low wind power and the batteries have to compensate the lack of power, so that the isolated micro grid has enough power to supply at least the priority loads. In this paper are presented the hardware and the control algorithm for the developed system. The topology was previously tested in computer simulations, using the software PSIM 9.0, and then validated with the implementation of a laboratory prototype.

Bidirectional battery charger with grid-to-vehicle, vehicle-to-grid and vehicle-to-home technologies

This paper presents the development of na on-board bidirectional battery charger for Electric Vehicles (EVs) targeting Grid-to-Vehicle (G2V), Vehicle-to-Grid (V2G), and Vehicle-to-Home (V2H) technologies. During the G2V operation mode the batteries are charged from the power grid with sinusoidal current and unitary power factor. During the V2G operation mode the energy stored in the batteries can be delivered back to the power grid contributing to the power system stability. In the V2H operation mode the energy stored in the batteries can be used to supply home loads during power outages, or to supply loads in places without connection to the power grid. Along the paper the hardware topology of the bidirectional battery charger is presented and the control algorithms are explained. Some considerations about the sizing of the AC side passive filter are taken into account in order to improve the performance in the three operation modes. The adopted topology and control algorithms are accessed through computer simulations and validated by experimental results achieved with a developed laboratory prototype operating in the different scenarios.