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.

Optimal brake specific fuel consumption trajectory for stand-alone variable speed Diesel Gen-Set

Energy efficiency plays an important role to the CO2 emissions reduction, combating climate change and improving the competitiveness of the economy. The problem presented here is related to the use of stand-alone diesel gen-sets and its high specific fuel consumptions when operates at low loads. The variable speed gen-set concept is explained as an energy-saving solution to improve this system efficiency. This paper details how an optimum fuel consumption trajectory based on experimentally Diesel engine power map is obtained.

Coastal sedimentary environments and sea-level changes

A detailed knowledge of the 3-D arrangement and lateral facies relationships of the stacking patterns in coastal deposits is essential to approach many geological problems such as precise tracing of sea level changes, particularly during small scale fluctuations. These are useful data regarding the geodynamic evolution of basin margins and yield profit in oil exploration. Sediment supply, wave-and tidal processes, coastal morphology, and accommodation space generated by eustasy and tectonics govern the highly variable architecture of sedimentary bodies deposited in coastal settings. But these parameters change with time, and erosional surfaces may play a prominent role in areas located towards land. Besides, lateral shift of erosional or even depositional loci very often results in destruction of large parts of the sediment record. Several case studies illustrate some commonly found arrangements of facies and their distinguishing features. The final aim is to get the best results from the sedimentological analysis of coastal units.

Ocorrência de ouro nos depósitos pliocénicos da região de Cruz de Pau (Seixal)

Recently had been discovery, in the area of the construction of the Carla Sacramento Athletics Stadium at Cruz de Pau (Seixal), a set of stopes and wells with characteristics of ancient Roman mining activities. The old mining works are incised in pliocene sandy formations with conglomeratic facies, where four preliminary samples were collected in a coarser level with subrounded pebbles. The heavy minerais of those samples were studied in accordance with the Heavy Mineral Concentrate Laboratory of the IGM. The previously mentioned facies has interesting gold percentages and the presence of grey (nodular) and classic monazite, xenotime, cassiterite, spinels s.l., ilmenite and rutile. The morphology of the gold grains as well as the heavy minerals shows two phases of transport; an initial fluvial phase and a secondary aeolian phase influenced their concentracion. The high percentage of toroid grains showing evidence of wind ablation, suggests that this was the main factor for reconcentration of the gold. The amount of gold particles obtained in the concentrates is considerable and in one sample, a grade of 3.2 ppm was calculated. The samples also have been analysed for Au + 34 elements by INAA and ICP-MS, the results of which show similar grades as previously obtained.

Relatório de estágio em marketing corporativo na empresa Insite IT GmbH

Relatório de estágio apresentado à Escola Superior de Comunicação Social como parte dos requisitos para obtenção de grau de mestre em Publicidade e Marketing.

Proposta de modelo de avaliação de desempenho das marcas no facebook

Relatório de estágio apresentado à Escola Superior de Comunicação Social como parte dos requisitos para obtenção de grau de mestre em Publicidade e Marketing.

A municipal level approach to the management of schistosomiasis control in Peri-Peri, MG, Brazil

A schistosomiasis control program was implemented between 1974/87 in Peri-Peri,. MG (622 inhabitants). Molluscicide (niclosamide) was applied at three monthly intervals in water sources with Biomphalaria glabrata, and individuals eliminating Schistosoma mansoni eggs in the feces were treated annually with oxamniquine. From 1974 to 1983 the control measures were undertaken by staff of the "René Rachou" Research Center FIOCRUZ (CPqRR), and from 1984 to 1987 these measures were included in the Capim Branco basic health network activities. During both periods, the prevalence, incidence, intensity of infection and hepatosplenic form as well as the number of infected snails decreased significantly. The prevalence decreased from 43.5 to 4.4%, the incidence from 19.0 to 2.9%, the overall intensity of S. mansoni from 281 to 87 and of the hepatosplenic form from 5.9 to 0.0%. The results obtained suggest that the municipal management of control measures was as effective as the vertical program conducted by CPqRR staff.

Avaliação do débito máximo da tosse (peak cough flow) na doença pulmonar obstrutiva crónica

Resumo Objectivos: Avaliação da Tosse em doentes com Doença Pulmonar Obstrutiva Crónica (DPOC). Identificar e determinar a relação dos factores preditivos que contribuem para a deterioração da capacidade de tosse nestes indivíduos. Tipo de estudo: Estudo observacional descritivo de natureza transversal. Definição dos casos: Os critérios de diagnóstico da DPOC são o quadro clínico e o Gold standard para diagnóstico da DPOC – a espirometria. População-alvo: Todos os utentes com patologia primária de DPOC diagnosticada que se desloquem ao serviço de função respiratória do Hospital de Viseu, para realizar provas. Método de Amostragem: Foi utilizada uma amostra aleatória constituída por todos os indivíduos, que cumpriram os critérios de inclusão, conscientes e colaborantes, que aceitaram participar neste estudo. Dimensão da amostra: Uma amostra de 55 indivíduos que se deslocaram ao serviço de função respiratória, entre Janeiro e Junho de 2009, para realizar provas de função respiratória. Condução do estudo: Os utentes que aceitaram participar neste estudo foram sujeitos a um questionário de dados clínicos e realizaram 5 testes: índice de massa corporal (IMC), estudo funcional respiratório e gasometria arterial, avaliação da força dos músculos respiratórios (PImax e PEmax) e avaliação do débito máximo da tosse (Peak Cough Flow). Análise estatística: Foram obtidos dados caracterizadores da amostra em estudo, sendo posteriormente correlacionado o valor de débito máximo da tosse (Peak Cough Flow) com os resultados obtidos para as avaliações do IMC, estudo funcional respiratório, PImax e PEmax, gasometria, avaliação da capacidade de Tosse e número de internamentos no último ano por agudização da DPOC. Tendo sido encontrados os valores de correlação entre o Peak Cough Flow e os restantes parâmetros. Resultados: Após análise dos resultados, foram obtidos os valores de Peak Cough Flow para a população com DPOC e verificou-se valores diminuídos em comparação com os valores normais da população, tendo-se verificado maiores valores de PCF em indivíduos do sexo masculino, em comparação aos valores do sexo feminino. Foi analisada a relação entre o PCF e a idade, peso, altura e IMC, não tendo sido encontrada relação, dado que a tosse não apresenta uma variação segundo os valores antropométricos, tal como a relação com os valores espirométricos. Quanto aos parâmetros funcionais respiratórios foram analisadas as relações com o PCF. Verificou-se relações significativas entre o PCF e o FEV1, a FVC, o PEF, apresentando uma relação positiva, onde maiores valores destes parâmetros estão correlacionados com maiores picos de tosse. Quanto a RAW e RV, o PCF apresenta uma relação negativa, onde uma maior resistência da via aérea ou doentes mais hiperinsuflados leva a menores valores de PCF. Por outro lado não foi encontrada relação entre o PCF e a FRC e o TLC. Quanto à força dos músculos respiratórios, verificou-se relação significativa com o PImax e a PEmax em que a fraqueza ao nível dos músculos respiratórios contribuem para um menor valor de PCF. Relativamente aos valores da gasometria arterial, verificou-se relação entre o PCF e a PaO2 de forma positiva, em que doentes hipoxémicos apresentam menores valores de tosse, e a PaCO2, de forma negativa, em que os doentes hipercápnicos apresentam menores valores de PCF tendo sido verificada relação entre o PCF e o pH e sO2. Quanto à relação entre o número de internamentos por agudização da DPOC no último ano e o PCF verificou-se uma relação significativa, onde um menor valor de PCF contribui para uma maior taxa de internamento por agudização da DPOC. Conclusão: Este conjunto de conclusões corrobora a hipótese inicialmente formulada, de que o Peak Cough Flow se encontra diminuído nos indivíduos com Doença Pulmonar Obstrutiva Crónica onde a variação do PCF se encontra directamente relacionada com os parâmetros funcionais respiratórios, com a força dos músculos respiratórios e com os valores de gasometria arterial. ABSTRACT: Aims: Cough evaluation in Chronic Obstructive Pulmonary Disease (COPD) patients. Identify and determine the relation of the predictive factors that contribute to the cough capacity degradation in this type of patients. Type of study: Descriptive observational study of transversal nature. Case definition: The COPD diagnosis criteria are the clinical presentation and the gold standard to the COPD diagnosis- the Spirometry. Target Population: Every patients, with primary pathology of COPD diagnosed, who went to the respiratory function service of Viseu hospital to perform tests. Sampling Method: It was used a random sample constituted by all the, conscious and cooperating individuals, who complied with the inclusion criteria and who accepted to make part of this study. Sample size: A sample of 55 individuals that went to the respiratory function service between January and June 2009 to perform respiratory function tests. Study: The patients who accepted to make part of this study were submitted to a clinical data questionary and performed 5 tests: body mass index (BMI), respiratory functional study, arterial blood gas level, evaluation of respiratory muscles strength (maximal inspiratory pressure (MIP) and maximum expiratory pressure (MEP)), and Peak Cough Flow evaluation. Statistic Analysis: Were obtained characterizing data of the sample in study, and later correlated the value of the Peak Cough Flow with the results from the evaluation of the body mass index (BMI), the respiratory functional study the MIP and MEP, the arterial blood gas level and also with the ability to cough evaluation and the number of hospitalizations in the last year for COPD exacerbations. The values of correlation between the Peak Cough Flow and the other parameters were found. Results: After analyzing the results, were obtained the values of Peak Cough Flow for the population with COPD. There were decreased values compared with the population normal values, having been found higher values of PCF in males compared to female values. It was analyzed the relation between the PCF and the age, weight, height and BMI but no relation was found on account of the fact that the cough does not show a variation according to anthropometric parameters, such as the relation with spirometric values. As for the respiratory functional parameters were analyzed relations with the PCF. There were significant relations between the PCF and FEV1, the FVC, the PEF, presenting a positive relation, where higher values of these parameters are correlated with higher incidence of cough. Concerning the RAW and RV, the PCF has a negative relation, in which a higher airway resistance or in more hyperinflated patients, leads to lower values of PCF. On the other hand no correlation was found between the PCF and the FRC and TLC. Regarding the respiratory muscle strength, there was a significant relation with the MIP and MEP, in which the weakness at the level of respiratory muscles contribute to a lower value of PCF. For values of arterial blood gas level, there was no relation between the PCF and PaO2, in a positive way, in which patients with hypoxemia present lower values of cough, and PaCO2, in a negative way in which hypercapnic patients had lower values of PCF, having being founded a relation between the PCF and the pH and sO2. As for the relation between the number of hospitalizations for COPD exacerbation in the last year and the PCF was found a significant relation, in which a smaller value of PCF contributes to a higher rate of hospitalization for COPD exacerbation. Conclusion: This set of findings supports the hypothesis first formulated that Peak Cough Flow is decreased in individuals with Chronic Obstructive Pulmonary Disease, in which the variation of the PCF is directly related to the respiratory function parameters, the strength of respiratory muscles and the values of arterial blood gases.

Race-to-halt energy saving strategies

Energy consumption is one of the major issues for modern embedded systems. Early, power saving approaches mainly focused on dynamic power dissipation, while neglecting the static (leakage) energy consumption. However, technology improvements resulted in a case where static power dissipation increasingly dominates. Addressing this issue, hardware vendors have equipped modern processors with several sleep states. We propose a set of leakage-aware energy management approaches that reduce the energy consumption of embedded real-time systems while respecting the real-time constraints. Our algorithms are based on the race-to-halt strategy that tends to run the system at top speed with an aim to create long idle intervals, which are used to deploy a sleep state. The effectiveness of our algorithms is illustrated with an extensive set of simulations that show an improvement of up to 8% reduction in energy consumption over existing work at high utilization. The complexity of our algorithms is smaller when compared to state-of-the-art algorithms. We also eliminate assumptions made in the related work that restrict the practical application of the respective algorithms. Moreover, a novel study about the relation between the use of sleep intervals and the number of pre-emptions is also presented utilizing a large set of simulation results, where our algorithms reduce the experienced number of pre-emptions in all cases. Our results show that sleep states in general can save up to 30% of the overall number of pre-emptions when compared to the sleep-agnostic earliest-deadline-first algorithm.

Forças em estruturas de acostagem descontínuas em zonas desabrigadas: avaliação de ferramentas de cálculo existentes

Dissertação para obtenção do grau de Mestre em Engenharia Civil na Área de especialização em Hidráulica

Análise sísmica e proposta de reforço de uma estrutura do séc. XIX sujeita a uma reabilitação parcial

Trabalho final de Mestrado para a obtenção do grau de mestre em Engenharia Civil

High-level Petri nets modules for embedded controllers design

Modular design is crucial to manage large-scale systems and to support the divide-and-conquer development approach. It allows hierarchical representations and, therefore, one can have a system overview, as well as observe component details. Petri nets are suitable to model concurrent systems, but lack on structuring mechanisms to support abstractions and the composition of sub-models, in particular when considering applications to embedded controllers design. In this paper we present a module construct, and an underlying high-level Petri net type, to model embedded controllers. Multiple interfaces can be declared in a module, thus, different instances of the same module can be used in different situations. The interface is a subset of the module nodes, through which the communication with the environment is made. Module places can be annotated with a generic type, overridden with a concrete type at instance level, and constants declared in a module may have a new value in each instance.

Materials selection for a set of multiple parts considering manufacturing costs and weight reduction with structural isoperformance using direct multisearch optimization

Materials selection is a matter of great importance to engineering design and software tools are valuable to inform decisions in the early stages of product development. However, when a set of alternative materials is available for the different parts a product is made of, the question of what optimal material mix to choose for a group of parts is not trivial. The engineer/designer therefore goes about this in a part-by-part procedure. Optimizing each part per se can lead to a global sub-optimal solution from the product point of view. An optimization procedure to deal with products with multiple parts, each with discrete design variables, and able to determine the optimal solution assuming different objectives is therefore needed. To solve this multiobjective optimization problem, a new routine based on Direct MultiSearch (DMS) algorithm is created. Results from the Pareto front can help the designer to align his/hers materials selection for a complete set of materials with product attribute objectives, depending on the relative importance of each objective.

Modelo de avaliação de risco de crédito - rating - uma abordagem

Dissertação de Mestrado apresentada ao Instituto Superior de Contabilidade e Administração do Porto para a obtenção do Grau de Mestre em Auditoria, sob a orientação de Mestre Adalmiro Álvaro Malheiro de Castro Andrade Pereira

Assessing the balance between biodiversity conservation and coastal and estuarine management of the Sado Estuary Natural Reserve, Portugal, using BIO-SAFE

Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do grau de Mestre em Engenharia do Ambiente, perfil de Engenharia Ecológica