Simplified wind turbine models for wind energy integration into power systems

This paper analyses the boundaries of simplified wind turbine models used to represent the behavior of wind turbines in order to conduct power system stability studies. Based on experimental measurements, the response of recent simplified (also known as generic) wind turbine models that are currently being developed by the International Standard IEC 61400-27 is compared to complex detailed models elaborated by wind turbine manufacturers. This International Standard, whose Technical Committee was convened in October 2009, is focused on defining generic simulation models for both wind turbines (Part 1) and wind farms (Part 2). The results of this work provide an improved understanding of the usability of generic models for conducting power system simulations.

Spatio-temporal patterns of tuberculosis incidence in Ribeirão Preto, State of São Paulo, southeast Brazil, and their relationship with social vulnerability: a Bayesian analysis

INTRODUCTION: The purpose of this ecological study was to evaluate the urban spatial and temporal distribution of tuberculosis (TB) in Ribeirão Preto, State of São Paulo, southeast Brazil, between 2006 and 2009 and to evaluate its relationship with factors of social vulnerability such as income and education level. METHODS: We evaluated data from TBWeb, an electronic notification system for TB cases. Measures of social vulnerability were obtained from the SEADE Foundation, and information about the number of inhabitants, education and income of the households were obtained from Brazilian Institute of Geography and Statistics. Statistical analyses were conducted by a Bayesian regression model assuming a Poisson distribution for the observed new cases of TB in each area. A conditional autoregressive structure was used for the spatial covariance structure. RESULTS: The Bayesian model confirmed the spatial heterogeneity of TB distribution in Ribeirão Preto, identifying areas with elevated risk and the effects of social vulnerability on the disease. We demonstrated that the rate of TB was correlated with the measures of income, education and social vulnerability. However, we observed areas with low vulnerability and high education and income, but with high estimated TB rates. CONCLUSIONS: The study identified areas with different risks for TB, given that the public health system deals with the characteristics of each region individually and prioritizes those that present a higher propensity to risk of TB. Complex relationships may exist between TB incidence and a wide range of environmental and intrinsic factors, which need to be studied in future research.

Development of 3D in vitro models for prediction of hepatic metabolism and toxicity

The development of human cell models that recapitulate hepatic functionality allows the study of metabolic pathways involved in toxicity and disease. The increased biological relevance, cost-effectiveness and high-throughput of cell models can contribute to increase the efficiency of drug development in the pharmaceutical industry. Recapitulation of liver functionality in vitro requires the development of advanced culture strategies to mimic in vivo complexity, such as 3D culture, co-cultures or biomaterials. However, complex 3D models are typically associated with poor robustness, limited scalability and compatibility with screening methods. In this work, several strategies were used to develop highly functional and reproducible spheroid-based in vitro models of human hepatocytes and HepaRG cells using stirred culture systems. In chapter 2, the isolation of human hepatocytes from resected liver tissue was implemented and a liver tissue perfusion method was optimized towards the improvement of hepatocyte isolation and aggregation efficiency, resulting in an isolation protocol compatible with 3D culture. In chapter 3, human hepatocytes were co-cultivated with mesenchymal stem cells (MSC) and the phenotype of both cell types was characterized, showing that MSC acquire a supportive stromal function and hepatocytes retain differentiated hepatic functions, stability of drug metabolism enzymes and higher viability in co-cultures. In chapter 4, a 3D alginate microencapsulation strategy for the differentiation of HepaRG cells was evaluated and compared with the standard 2D DMSO-dependent differentiation, yielding higher differentiation efficiency, comparable levels of drug metabolism activity and significantly improved biosynthetic activity. The work developed in this thesis provides novel strategies for 3D culture of human hepatic cell models, which are reproducible, scalable and compatible with screening platforms. The phenotypic and functional characterization of the in vitro systems performed contributes to the state of the art of human hepatic cell models and can be applied to the improvement of pre-clinical drug development efficiency of the process, model disease and ultimately, development of cell-based therapeutic strategies for liver failure.

Predicting market direction with hidden Markov models

This paper develops the model of Bicego, Grosso, and Otranto (2008) and applies Hidden Markov Models to predict market direction. The paper draws an analogy between financial markets and speech recognition, seeking inspiration from the latter to solve common issues in quantitative investing. Whereas previous works focus mostly on very complex modifications of the original hidden markov model algorithm, the current paper provides an innovative methodology by drawing inspiration from thoroughly tested, yet simple, speech recognition methodologies. By grouping returns into sequences, Hidden Markov Models can then predict market direction the same way they are used to identify phonemes in speech recognition. The model proves highly successful in identifying market direction but fails to consistently identify whether a trend is in place. All in all, the current paper seeks to bridge the gap between speech recognition and quantitative finance and, even though the model is not fully successful, several refinements are suggested and the room for improvement is significant.

Knowledge management framework based on brain models and human physiology

The life of humans and most living beings depend on sensation and perception for the best assessment of the surrounding world. Sensorial organs acquire a variety of stimuli that are interpreted and integrated in our brain for immediate use or stored in memory for later recall. Among the reasoning aspects, a person has to decide what to do with available information. Emotions are classifiers of collected information, assigning a personal meaning to objects, events and individuals, making part of our own identity. Emotions play a decisive role in cognitive processes as reasoning, decision and memory by assigning relevance to collected information. The access to pervasive computing devices, empowered by the ability to sense and perceive the world, provides new forms of acquiring and integrating information. But prior to data assessment on its usefulness, systems must capture and ensure that data is properly managed for diverse possible goals. Portable and wearable devices are now able to gather and store information, from the environment and from our body, using cloud based services and Internet connections. Systems limitations in handling sensorial data, compared with our sensorial capabilities constitute an identified problem. Another problem is the lack of interoperability between humans and devices, as they do not properly understand human’s emotional states and human needs. Addressing those problems is a motivation for the present research work. The mission hereby assumed is to include sensorial and physiological data into a Framework that will be able to manage collected data towards human cognitive functions, supported by a new data model. By learning from selected human functional and behavioural models and reasoning over collected data, the Framework aims at providing evaluation on a person’s emotional state, for empowering human centric applications, along with the capability of storing episodic information on a person’s life with physiologic indicators on emotional states to be used by new generation applications.

Flood resilient housing recovery models: a theoretical case study in Maldives

Natural disasters are events that cause general and widespread destruction of the built environment and are becoming increasingly recurrent. They are a product of vulnerability and community exposure to natural hazards, generating a multitude of social, economic and cultural issues of which the loss of housing and the subsequent need for shelter is one of its major consequences. Nowadays, numerous factors contribute to increased vulnerability and exposure to natural disasters such as climate change with its impacts felt across the globe and which is currently seen as a worldwide threat to the built environment. The abandonment of disaster-affected areas can also push populations to regions where natural hazards are felt more severely. Although several actors in the post-disaster scenario provide for shelter needs and recovery programs, housing is often inadequate and unable to resist the effects of future natural hazards. Resilient housing is commonly not addressed due to the urgency in sheltering affected populations. However, by neglecting risks of exposure in construction, houses become vulnerable and are likely to be damaged or destroyed in future natural hazard events. That being said it becomes fundamental to include resilience criteria, when it comes to housing, which in turn will allow new houses to better withstand the passage of time and natural disasters, in the safest way possible. This master thesis is intended to provide guiding principles to take towards housing recovery after natural disasters, particularly in the form of flood resilient construction, considering floods are responsible for the largest number of natural disasters. To this purpose, the main structures that house affected populations were identified and analyzed in depth. After assessing the risks and damages that flood events can cause in housing, a methodology was proposed for flood resilient housing models, in which there were identified key criteria that housing should meet. The same methodology is based in the US Federal Emergency Management Agency requirements and recommendations in accordance to specific flood zones. Finally, a case study in Maldives – one of the most vulnerable countries to sea level rise resulting from climate change – has been analyzed in light of housing recovery in a post-disaster induced scenario. This analysis was carried out by using the proposed methodology with the intent of assessing the resilience of the newly built housing to floods in the aftermath of the 2004 Indian Ocean Tsunami.

The future of airline business models:

This research is titled “The Future of Airline Business Models: Which Will Win?” and it is part of the requirements for the award of a Masters in Management from NOVA BSE and another from Luiss Guido Carlo University. The purpose is to elaborate a complete market analysis of the European Air Transportation Industry in order to predict which Airlines, strategies and business models may be successful in the next years. First, an extensive literature review of the business model concept has been done. Then, a detailed overview of the main European Airlines and the strategies that they have been implementing so far has been developed. Finally, the research is illustrated with three case studies

Composition, abundance and aspects of temporal variation in the distribution of Anopheles species in an area of Eastern Amazonia

Introduction The diverse and complex environmental conditions of the Amazon Basin favor the breeding and development of Anopheles species. This study aimed to describe the composition, abundance and temporal frequency of Anopheles species and to correlate these factors with precipitation, temperature and relative humidity. Methods The study was conducted in the District of Coração, State of Amapá, Brazil. Samples were collected monthly during three consecutive nights, from 6:00 PM to 10:00 PM, from December 2010 to November 2011. In addition, four 12-hour collections (i.e., 6:00 PM to 6:00 AM) were performed during this period. Results A total of 1,230 Anopheles specimens were collected. In the monthly collections, Anopheles darlingi was the predominant species, followed by An. braziliensis and An. albitarsis s.l., whereas An. darlingi, An. peryassui and An. braziliensis were the most frequent species collected in the 12-hour collections. The greatest number of anophelines was collected in September (the dry season). The highest frequency of anophelines was observed for An. darlingi during September, when there were the least rainfalls of the year, along with lower relative humidity and higher temperatures. There was little variation in the abundance of this species in other months, with the exception of slight increases in February, July and August. Conclusions The major malaria vectors, An. darlingi and An. albitarsis s.l. (likely An. marajoara), were the most abundant species collected in the study area. Consequently, prevention and control measures should be taken to prevent malaria outbreaks in the District of Coração.

Temporal, spatial and spatiotemporal analysis of the occurrence of visceral leishmaniasis in humans in the City of Birigui, State of São Paulo, from 1999 to 2012

Introduction In 1999, Birigui and Araçatuba were the first municipalities in the State of São Paulo to present autochthonous cases of visceral leishmaniasis in humans (VLH). The aim of this study was to describe the temporal, spatial and spatiotemporal behaviors of VLH in Birigui. Methods Secondary data were obtained from the Notifiable Diseases Information System from 1999 to 2012. The incidence, mortality and case fatality rates by sex and age were calculated. The cases of VLH were geocoded and grouped according to census tracts. Local empirical Bayesian incidence rates were calculated. The existence of spatial and spatiotemporal clusters was investigated using SaTScan software. Results There were 156 confirmed cases of autochthonous VLH. The incidence rate was higher in the 0-4-year-old children, and the mortality and case fatality rates were higher in people aged 60 years and older. The peaks of incidence occurred in 2006 and 2011. The Bayesian rates identified the presence of VLH in all of the census tracts in the municipality; however, spatial and spatiotemporal clusters were found in the central area of the municipality. Conclusions Birigui, located in the Araçatuba region, has recently experienced increasing numbers of VLH cases; this increase is contrary to the behavior observed over the entire region, which has shown a decreasing trend in the number of VLH cases. The observations that the highest incidence is in children 0-4 years old and the highest mortality is in people 60 years and older are in agreement with the expected patterns of VLH.

Avaliação económica em transplantação renal : abordagem estratégica do processo de doação e análise de custo-utilidade do programa de transplantação renal versus hemodiálise

SUMÁRIO - O desafio atual da Saúde Pública é assegurar a sustentabilidade financeira do sistema de saúde. Em ambiente de recursos escassos, as análises económicas aplicadas à prestação dos cuidados de saúde são um contributo para a tomada de decisão que visa a maximização do bem-estar social sujeita a restrição orçamental. Portugal é um país com 10,6 milhões de habitantes (2011) com uma incidência e prevalência elevadas de doença renal crónica estadio 5 (DRC5), respetivamente, 234 doentes por milhão de habitantes (pmh) e 1.600 doentes/pmh. O crescimento de doenças associadas às causas de DRC, nomeadamente, diabetes Mellitus e hipertensão arterial, antecipam uma tendência para o aumento do número de doentes. Em 2011, dos 17.553 doentes em tratamento substitutivo renal, 59% encontrava-se em programa de hemodiálise (Hd) em centros de diálise extra-hospitalares, 37% viviam com um enxerto renal funcionante e 4% estavam em diálise peritoneal (SPN, 2011). A lista ativa para transplante (Tx) renal registava 2.500 doentes (SPN 2009). O Tx renal é a melhor modalidade terapêutica pela melhoria da sobrevida, qualidade de vida e relação custo-efetividade, mas a elegibilidade para Tx e a oferta de órgãos condicionam esta opção. Esta investigação desenvolveu-se em duas vertentes: i) determinar o rácio custo-utilidade incremental do Tx renal comparado com a Hd; ii) avaliar a capacidade máxima de dadores de cadáver em Portugal, as características e as causas de morte dos dadores potenciais a nível nacional, por hospital e por Gabinete Coordenador de Colheita e Transplantação (GCCT), e analisar o desempenho da rede de colheita de órgãos para Tx. Realizou-se um estudo observacional/não interventivo, prospetivo e analítico que incidiu sobre uma coorte de doentes em Hd que foi submetida a Tx renal. O tempo de seguimento mínimo foi de um ano e máximo de três anos. No início do estudo, colheram-se dados sociodemográficos e clínicos em 386 doentes em Hd, elegíveis para Tx renal. A qualidade de vida relacionada com a saúde (QVRS) foi avaliada nos doentes em Hd (tempo 0) e nos transplantados, aos três, seis, 12 meses, e depois, anualmente. Incluíram-se os doentes que por falência do enxerto renal transitaram para Hd. Na sua medição, utilizou-se um instrumento baseado em preferências da população, o EuroQol-5D, que permite o posterior cálculo dos QALY. Num grupo de 82 doentes, a QVRS em Hd foi avaliada em dois tempos de resposta o que permitiu a análise da sua evolução. Realizou-se uma análise custo-utilidade do Tx renal comparado com a Hd na perspetiva da sociedade. Identificaram-se os custos diretos, médicos e não médicos, e as alterações de produtividade em Hd e Tx renal. Incluíram-se os custos da colheita de órgãos, seleção dos candidatos a Tx renal e follow-up dos dadores vivos. Cada doente transplantado foi utilizado como controle de si próprio em diálise. Avaliou-se o custo médio anual em programa de Hd crónica relativo ao ano anterior à Tx renal. Os custos do Tx foram avaliados prospetivamente. Considerou-se como horizonte temporal o ciclo de vida nas duas modalidades. Usaram-se taxas de atualização de 0%, 3% e 5% na atualização dos custos e QALY e efetuaram-se análises de sensibilidade one way. Entre 2008 e 2010, 65 doentes foram submetidos a Tx renal. Registaram-se, prospetivamente, os resultados em saúde incluíndo os internamentos e os efeitos adversos da imunossupressão, e o consumo dos recursos em saúde. Utilizaram-se modelos de medidas repetidas na avaliação da evolução da QVRS e modelos de regressão múltipla na análise da associação da QVRS e dos custos do transplante com as características basais dos doentes e os eventos clínicos. Comparativamente à Hd, observou-se melhoria da utilidade ao 3º mês de Tx e a qualidade de vida aferida pela escala EQ-VAS melhorou em todos os tempos de observação após o Tx renal. O custo médio da Hd foi de 32.567,57€, considerado uniforme ao longo do tempo. O custo médio do Tx renal foi de 60.210,09€ no 1º ano e 12.956,77€ nos anos seguintes. O rácio custo-utilidade do Tx renal vs Hd crónica foi de 2.004,75€/QALY. A partir de uma sobrevivência do enxerto de dois anos e cinco meses, o Tx associou-se a poupança dos custos. Utilizaram-se os dados nacionais dos Grupos de Diagnóstico Homogéneos e realizou-se um estudo retrospectivo que abrangeu as mortes ocorridas em 34 hospitais com colheita de órgãos, em 2006. Considerou-se como dador potencial o indivíduo com idade entre 1-70 anos cuja morte ocorrera a nível hospitalar, e que apresentasse critérios de adequação à doação de rim. Analisou-se a associação dos dadores potenciais com características populacionais e hospitalares. O desempenho das organizações de colheita de órgãos foi avaliado pela taxa de conversão (rácio entre os dadores potenciais e efetivos) e pelo número de dadores potenciais por milhão de habitantes a nível nacional, regional e por Gabinete Coordenador de Colheita e Transplantação (GCCT). Identificaram-se 3.838 dadores potenciais dos quais 608 apresentaram códigos da Classificação Internacional de Doenças, 9.ª Revisão, Modificações Clínicas (CID- 9-MC) que, com maior frequência, evoluem para a morte cerebral. O modelo logit para dados agrupados identificou a idade, o rácio da lotação em Unidades de Cuidados Intensivos e lotação de agudos, existência de GCCT e de Unidade de Transplantação, e mortalidade por acidente de trabalho como fatores preditivos da conversão dum dador potencial em efetivo e através das estimativas do modelo logit quantificou-se a probabilidade dessa conversão. A doação de órgãos deve ser assumida como uma prioridade e as autoridades em saúde devem assegurar o financiamento dos hospitais com programas de doação, evitando o desperdício de órgãos para transplantação, enquanto um bem público e escasso. A colheita de órgãos deve ser considerada uma opção estratégica da atividade hospitalar orientada para a organização e planeamento de serviços que maximizem a conversão de dadores potenciais em efetivos incluindo esse critério como medida de qualidade e efetividade do desempenho hospitalar. Os resultados deste estudo demonstram que: 1) o Tx renal proporciona ganhos em saúde, aumento da sobrevida e qualidade de vida, e poupança de custos; 2) em Portugal, a taxa máxima de eficácia da conversão dos dadores cadavéricos em dadores potenciais está longe de ser atingida. O investimento na rede de colheita de órgãos para Tx é essencial para assegurar a sustentabilidade financeira e promover a qualidade, eficiência e equidade dos cuidados em saúde prestados na DRC5.

Essays on bounded rationality: Individual decision and strategic interaction

Economics is a social science which, therefore, focuses on people and on the decisions they make, be it in an individual context, or in group situations. It studies human choices, in face of needs to be fulfilled, and a limited amount of resources to fulfill them. For a long time, there was a convergence between the normative and positive views of human behavior, in that the ideal and predicted decisions of agents in economic models were entangled in one single concept. That is, it was assumed that the best that could be done in each situation was exactly the choice that would prevail. Or, at least, that the facts that economics needed to explain could be understood in the light of models in which individual agents act as if they are able to make ideal decisions. However, in the last decades, the complexity of the environment in which economic decisions are made and the limits on the ability of agents to deal with it have been recognized, and incorporated into models of decision making in what came to be known as the bounded rationality paradigm. This was triggered by the incapacity of the unboundedly rationality paradigm to explain observed phenomena and behavior. This thesis contributes to the literature in three different ways. Chapter 1 is a survey on bounded rationality, which gathers and organizes the contributions to the field since Simon (1955) first recognized the necessity to account for the limits on human rationality. The focus of the survey is on theoretical work rather than the experimental literature which presents evidence of actual behavior that differs from what classic rationality predicts. The general framework is as follows. Given a set of exogenous variables, the economic agent needs to choose an element from the choice set that is avail- able to him, in order to optimize the expected value of an objective function (assuming his preferences are representable by such a function). If this problem is too complex for the agent to deal with, one or more of its elements is simplified. Each bounded rationality theory is categorized according to the most relevant element it simplifes. Chapter 2 proposes a novel theory of bounded rationality. Much in the same fashion as Conlisk (1980) and Gabaix (2014), we assume that thinking is costly in the sense that agents have to pay a cost for performing mental operations. In our model, if they choose not to think, such cost is avoided, but they are left with a single alternative, labeled the default choice. We exemplify the idea with a very simple model of consumer choice and identify the concept of isofin curves, i.e., sets of default choices which generate the same utility net of thinking cost. Then, we apply the idea to a linear symmetric Cournot duopoly, in which the default choice can be interpreted as the most natural quantity to be produced in the market. We find that, as the thinking cost increases, the number of firms thinking in equilibrium decreases. More interestingly, for intermediate levels of thinking cost, an equilibrium in which one of the firms chooses the default quantity and the other best responds to it exists, generating asymmetric choices in a symmetric model. Our model is able to explain well-known regularities identified in the Cournot experimental literature, such as the adoption of different strategies by players (Huck et al. , 1999), the inter temporal rigidity of choices (Bosch-Dom enech & Vriend, 2003) and the dispersion of quantities in the context of di cult decision making (Bosch-Dom enech & Vriend, 2003). Chapter 3 applies a model of bounded rationality in a game-theoretic set- ting to the well-known turnout paradox in large elections, pivotal probabilities vanish very quickly and no one should vote, in sharp contrast with the ob- served high levels of turnout. Inspired by the concept of rhizomatic thinking, introduced by Bravo-Furtado & Côrte-Real (2009a), we assume that each per- son is self-delusional in the sense that, when making a decision, she believes that a fraction of the people who support the same party decides alike, even if no communication is established between them. This kind of belief simplifies the decision of the agent, as it reduces the number of players he believes to be playing against { it is thus a bounded rationality approach. Studying a two-party first-past-the-post election with a continuum of self-delusional agents, we show that the turnout rate is positive in all the possible equilibria, and that it can be as high as 100%. The game displays multiple equilibria, at least one of which entails a victory of the bigger party. The smaller one may also win, provided its relative size is not too small; more self-delusional voters in the minority party decreases this threshold size. Our model is able to explain some empirical facts, such as the possibility that a close election leads to low turnout (Geys, 2006), a lower margin of victory when turnout is higher (Geys, 2006) and high turnout rates favoring the minority (Bernhagen & Marsh, 1997).

Relação entre as variáveis sociais, económicas e ambientais com o padrão da distribuição espaço-temporal dos casos de Dengue por munícipio no Brasil : de 2008 até 2012, utilizando o SOM

Atualmente, um dos principais desafios que afeta a saúde pública no Brasil é a crescente evolução no número de casos e epidemias provocados pelo vírus da dengue. Não existem estudos suficientes que consigam elucidar quais fatores contribuem para a evolução das epidemias de Dengue. Fatores como condições sanitárias, localização geográfica, investimentos financeiros em infraestrutura e qualidade de vida podem estar relacionados com a incidência de Dengue. Além disso, outra questão que merece um maior destaque é o estudo para se identificar o grau de impacto das variáveis determinantes da dengue e se existe um padrão que está correlacionado com a taxa de incidência. Desta forma, este trabalho tem como objetivo principal a correlação da taxa de incidência da dengue na população de cada município brasileiro, utilizando dados relativos aos aspectos sociais, econômicos, demográficos e ambientais. Outra contribuição relevante do trabalho, foi a análise dos padrões de distribuição espacial da taxa de incidência de Dengue e sua relação com os padrões encontrados utilizando as variáveis socioeconômicas e ambientais, sobretudo analisando a evolução temporal no período de 2008 até 2012. Para essa análises, utilizou-se o Sistema de Informação Geográfica (SIG) aliado com a mineração de dados, através da metodologia de rede neural mais especificamente o mapa auto organizável de Kohonen ou self-organizing maps (SOM). Tal metodologia foi empregada para a identificação de padrão de agrupamentos dessas variáveis e sua relação com as classes de incidência de dengue no Brasil (Alta, Média e Baixa). Assim, este projeto contribui de forma significativa para uma melhor compreensão dos fatores que estão associados à ocorrência de Dengue, e como essa doença está correlacionada com fatores como: meio ambiente, infraestrutura e localização no espaço geográfico.

Temporal distribution of tuberculosis in the State of Amazonas, Brazil

Tuberculosis (TB) is one of the infectious diseases that contributes most to the morbidity and mortality of millions of people worldwide. Brazil is one of 22 countries that accounts for 80% of the tuberculosis global burden. The highest incidence rates in Brazil occur in the States of Amazonas and Rio de Janeiro. The aim of this study was to describe the temporal distribution of TB in the State of Amazonas. Between 2001 and 2011, 28,198 cases of tuberculosis were reported in Amazonas, distributed among 62 municipalities, with the capital Manaus reporting the highest (68.7%) concentration of cases. Tuberculosis was more prevalent among males (59.3%) aged 15 to 34 years old (45.5%), whose race/color was predominantly pardo (64.7%) and who had pulmonary TB (84.3%). During this period, 81 cases of multidrug-resistant TB were registered, of which the highest concentration was reported from 2008 onward (p = 0.002). The municipalities with the largest numbers of indigenous individuals affected were São Gabriel da Cachoeira (93%), Itamarati (78.1%), and Santa Isabel do Rio Negro (70.1%). The future outlook for this region includes strengthening the TB control at the primary care level, by expanding diagnostic capabilities, access to treatment, research projects developed in collaboration with the Dr. Heitor Vieira Dourado Tropical Medicine Foundation .;Fundação de Medicina Tropical Dr. Heitor Vieira Dourado (FMT-HVD).; and financing institutions, such as the project for the expansion of the Clinical Research Center and the creation of a hospital ward for individuals with transmissible respiratory diseases, including TB.

Building 3D City Models: Testing and Comparing Laser Scanning and Low-Cost UAV Data Using FOSS Technologies

Contém resumo

Damage propagation in composite Materials meso-mechanical models

Composite materials have a complex behavior, which is difficult to predict under different types of loads. In the course of this dissertation a methodology was developed to predict failure and damage propagation of composite material specimens. This methodology uses finite element numerical models created with Ansys and Matlab softwares. The methodology is able to perform an incremental-iterative analysis, which increases, gradually, the load applied to the specimen. Several structural failure phenomena are considered, such as fiber and/or matrix failure, delamination or shear plasticity. Failure criteria based on element stresses were implemented and a procedure to reduce the stiffness of the failed elements was prepared. The material used in this dissertation consist of a spread tow carbon fabric with a 0°/90° arrangement and the main numerical model analyzed is a 26-plies specimen under compression loads. Numerical results were compared with the results of specimens tested experimentally, whose mechanical properties are unknown, knowing only the geometry of the specimen. The material properties of the numerical model were adjusted in the course of this dissertation, in order to find the lowest difference between the numerical and experimental results with an error lower than 5% (it was performed the numerical model identification based on the experimental results).