32 resultados para WIDE-RANGE CURRENT MEASUREMENT


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Micro- and nano-patterned materials are of great importance for the design of new nanoscale electronic, optical and mechanical devices, ranging from sensors to displays. A prospective system that can support a designed functionality is elastomeric polyurethane thin films with nano- or micromodulated surface structures ("wrinkles"). These wrinkles can be induced on different lengthscales by mechanically stretching the films, without the need for any sophisticated lithographic techniques. In the present article we focus on the experimental control of the wrinkling process. A simple model for wrinkle formation is also discussed, and some preliminary results reported. Hierarchical assembly of these tunable structures paves the way for the development of a new class of materials with a wide range of applications, from electronics to biomedicine.

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Dissertação apresentada à Escola Superior de Educação de Lisboa para obtenção de grau de mestre em Educação Artística, na Especialização de Artes Plásticas na Educação

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Relatório Final de Estágio apresentado à Escola Superior de Dança, com vista à obtenção do grau de Mestre em Ensino da Dança.

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I (Prática Pedagógica)- No que se refere à secção da tese dedicada ao estágio, esta pretende desenvolver uma síntese do que se passou ao longo deste ano lectivo. Durante o ano lectivo 2012/2013, tive a oportunidade de assistir a aulas ministradas pela professora Ana Valente. A tese procura focar variados aspectos das aulas a que assisti. De uma forma geral, o relatório do estágio evidencia vários aspectos: metodologias de ensino, questões motivacionais, relação aluno/professor, questões de disciplina, entre outras. No decorrer das aulas, foi possível constatar muitas dessas questões na prática. Tentei registar as actividades desenvolvidas nas aulas relativas a várias questões, nomeadamente questões relacionadas com a prática do instrumento, assim como outras relacionadas com a noção de musicalidade. Como resultado, esta secção apresenta diversos tipos de estratégias de ensino, ilustrando exemplos práticos que efectivamente se passaram nas aulas. É essencialmente, uma secção dedicada à reflexão sobre metodologias de ensino e estudo. A segunda parte desta secção é relativa à análise das gravações das aulas dadas por mim e pretende sobretudo focar-se na crítica pessoal. É uma parte importante do estágio, em que tenho a oportunidade de observar a minha forma pedagógica de lidar com os alunos. Por fim, a terceira parte do relatório refere-se à observação crítica da abordagem da professora tendo por base o meu ponto de vista. Esta parte pretende essencialmente descrever e analisar a forma como a professora dá as aulas. Com base no que disse anteriormente, esta parte do trabalho mostra mais em detalhe as metodologias e estratégias de ensino utilizadas pela professora em questão. De um modo geral, esta secção pretende descrever as três vertentes que mencionei anteriormente (relatório das aulas, análise das gravações, observação crítica ao método pedagógico da professora).

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This paper presents a programable perturbation and observation control implementation for a wind generation system and its power electronic converter. The objective of the method in this particular application is to adjust the power delivered to charge a battery to its maximum and allowable value, function of the real values of several parameters and their continuous variation, the most important the wind velocity and the turbine efficiency. Also, to improve the power throughput and to use the turbine and generator marginal zones of operation, an unusual power converter is used, allowing a wide range for the input voltage values. The implemented control is continuously measuring the actual power and looks for a new and powerful operation point. © 2014 IEEE.

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Worldwide formaldehyde is manipulated with diverse usage properties, since industrial purposes to health laboratory objectives, representing the economic importance of this chemical agent. Therefore, many people are exposed to formaldehyde environmentally and/or occupationally. Considering the latter, there was recommended occupational exposure limits based on threshold mechanisms, limit values and indoor guidelines. Formaldehyde is classified by the International Agency for Cancer Research (IARC) as carcinogenic to humans (group 1), since a wide range of epidemiological studies in occupational exposure settings have suggested possible links between the concentration and duration of exposure and elevated risks of nasopharyngeal cancer, and others cancers, and more recently, with leukemia. Although there are different classifications, such as U.S. EPA that classified formaldehyde as a B1 compound, probable human carcinogen under the conditions of unusually high or prolonged exposure, on basis of limited evidence in humans but with sufficient evidence in animals. Formaldehyde genotoxicity is well-known, being a direct-acting genotoxic compound positively associated for almost all genetic endpoints evaluated in bacteria, yeast, fungi, plants, insects, nematodes, and cultured mammalian cells. There are many human biomonitoring studies that associate formaldehyde occupational exposure to genomic instability, and consequently possible health effects. Besides the link with cancer, also other pathologies and symptoms are associated with formaldehyde exposure, namely respiratory disorders such as asthma, and allergic contact dermatitis. Nowadays, there are efforts to reduce formaldehyde exposure, namely indoor. Europe and United States developed more strict regulation regarding formaldehyde emissions from materials containing this agent. Despite the regulations and restrictions, formaldehyde still continues to be difficult to eliminate or substitute, being biomonitoring an important tool to control possible future health effects.

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Mestrado em Gestão e Empreendedorismo

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Mesquita, Ana Rita Biscaia de Melo - O papel da Televisão interna na relação com os colaboradores da TAP Portugal. Lisboa: Escola Superior de Comunicação Social, 2014. Relatório de estágio.

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Relatório de estágio apresentado à Escola Superior de Comunicação Social como parte dos requisitos para obtenção de grau de mestre em Gestão Estratégica das Relações Públicas.

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This paper presents a programable perturbation and observation control implementation for a wind generation system and its power electronic converter. The objective of the method in this particular application is to adjust the power delivered to charge a battery to its maximum and allowable value, function of the real values of several parameters and their continuous variation, the most important the wind velocity and the turbine efficiency. Also, to improve the power throughput and to use the turbine and generator marginal zones of operation, an unusual power converter is used, allowing a wide range for the input voltage values. The implemented control is continuously measuring the actual power and looks for a new and powerful operation point. © 2014 IEEE.

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Laccases are multi-copper oxidases that oxidise a wide range of substrates including phenol and aniline derivatives, which could be further involved in coupling reactions leading to the formation of dimeric and trimeric structures. This paper describes the enzyme-mediated dimerisation of several ortho and meta, para-disubstituted aromatic amines into phenazine ("head-to-tail" dimers) and phenoxazinone chromophores. The redox properties of substituted aromatic amines were studied by cyclic voltammetry and the kinetic constants of CotA and Trametes versicolor laccases were measured for selected aromatic amines. The structure of novel enzymatically synthesised phenazine and phenoxazinone dyes using CotA laccase was assessed by NMR and MS. Overall our data show that this enzymatic green process is an efficient alternative to the classic chemical oxidation of aromatic amines and phenols, with an impact on the broad field of applications of these heterocyclic compounds.

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Liquid crystalline cellulosic-based solutions described by distinctive properties are at the origin of different kinds of multifunctional materials with unique characteristics. These solutions can form chiral nematic phases at rest, with tuneable photonic behavior, and exhibit a complex behavior associated with the onset of a network of director field defects under shear. Techniques, such as Nuclear Magnetic Resonance (NMR), Rheology coupled with NMR (Rheo-NMR), rheology, optical methods, Magnetic Resonance Imaging (MRI), Wide Angle X-rays Scattering (WAXS), were extensively used to enlighten the liquid crystalline characteristics of these cellulosic solutions. Cellulosic films produced by shear casting and fibers by electrospinning, from these liquid crystalline solutions, have regained wider attention due to recognition of their innovative properties associated to their biocompatibility. Electrospun membranes composed by helical and spiral shape fibers allow the achievement of large surface areas, leading to the improvement of the performance of this kind of systems. The moisture response, light modulated, wettability and the capability of orienting protein and cellulose crystals, opened a wide range of new applications to the shear casted films. Characterization by NMR, X-rays, tensile tests, AFM, and optical methods allowed detailed characterization of those soft cellulosic materials. In this work, special attention will be given to recent developments, including, among others, a moisture driven cellulosic motor and electro-optical devices.

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This paper reviews the literature for lowering of dose to paediatric patients through use of exposure factors and additional filtration. Dose reference levels set by The International Commission on Radiological Protection (ICRP) will be considered. Guidance was put in place in 1996 requires updating to come into line with modern imaging equipment. There is a wide range of literature that specifies that grids should not be used on paediatric patients. Although much of the literature advocates additional filtration, contrasting views on the relative benefits of using aluminium or copper filtration, and their effects on dose reduction and image quality can vary. Changing kVp and mAs has an effect on the dose to the patient and image quality. Collimation protects adjacent structures whilst reducing scattered radiation.

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Relatório de Estágio apresentado à Escola Superior de Educação de Lisboa para obtenção de grau de mestre em Ensino do 1.º e do 2.º Ciclo do Ensino Básico

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Mestrado em Radiações Aplicadas às Tecnologias da Saúde