Modelagem e simulação do mecanismo biela manivela e análise estrutural de biela automotiva

Nowadays, the automotive industry is working to optimize the design of engines, in order to reduce the fuel consumption with acceptable efficiency ratio. This undergraduate thesis is aimed at perform a kinematic/dynamic analysis of a slider-crank mechanism that is part of a four stroke internal combustion engine, the same engine that was used in the analysis described by Montazersadhd and Fatemi (2007). Two algorithms were developed based on Kane’s method to calculate velocities and accelerations of the mechanism bodies, and provide the acting forces at connecting rod joints. A SimMechanics model was developed to simulate the engine, and monitoring the same parameters that were calculated with the algorithms. The results obtained with both approaches were satisfactory and showed good agreement with the values provided by Montazersadhd and Fatemi (2007). The obtained results showed that the axial component of the rod joint efforts was caused by the pressure exerted on the piston head,whereas the radial component was related with the action of inertia loads. Besides, this thesis presents a connecting rod assembly mesh that is going to be used for static and fatigue finite element analysis in the future

Calibração do Modelo de TBC para cálculos de espectros de raios-X

As normas nacionais e internacionais prevêem que a manutenção dos níveis de radiação deve estar abaixo do permitido. Sendo assim, a ICRP [1] (International Commission on Radiological Protection) exige métodos de otimização para garantir que o público esteja exposto aos menores níveis de radiação possíveis. Como método de otimização, aproximações teóricas e semi-empiricas podem realizar uma determinação do espectro de raios-X, sendo fundamental para o diagnóstico de energia, estimando a dose de radiações em pacientes e formulando modelos de blindagem. Métodos adequados de radioproteção foram desenvolvidos na física médica como a medicina nuclear, a radioterapia e a radiologia diagnóstica. Um dos métodos semi-empiricos utilizados é o modelo de TBC que é capaz de reproduzir e calcular os espectros gerados pelo anodo de tungstênio. Com o modelo de TBC modificado é possível também obedecer às exigências das barreiras protetoras presentes na radiologia, levando em conta a forma de onda arbitrária e a filtração adicional na geração do espectro não presente no modelo original. Além disso, realiza-se a calibração do espectro gerado para que o modelo de TBC represente a quantidade e comportamento de radiações típicas. Dessa forma, realiza-se uma revisão do modelo de TBC implementando-o ao programa matemático Matlab e comparando-o com os resultados adquiridos pelo Código MCNP-5 no Método de Monte Carlo. Os resultados encontrados são bastante satisfatórios, tanto em termos quantitativos quanto qualitativos dos feixes. Para a calibração, desenvolve-se uma análise dos espectros gerados pelo TBC Modificado aplicado ao programa Mathcad e Matlab sob as mesmas condições. Os espectros gerados apresentam o mesmo comportamento, diferindo em até 12% nos valores encontrados para camadas semi-redutoras, coeficiente de homogeneidade e energia efetiva

Análise de risco em carteiras

The work consists of analyzing the risk management of investments by applying statistical concepts, economic and mathematical models considering the assets on the market on renowned financial institution. The assessment of these risks becomes increasingly interesting in view of minimizing your losses thus maximizing your chances of gains in both markets boom as extreme uncertainty, even with the sudden changes of scenery. Introducing concepts of investment funds, as well as the classification of the types of funds as funds management and equity, its guidelines, the concept of market investment funds. The types of assets comprising the investment funds, their taxation rules beyond the incidents that market widely used by investors and skilled people, both physical and legal, who keep their resources in this modality. With the historical data collected yields of investment funds of the Bank of Brazil, is an accomplished inflation adjustment and calculated the mean and variance for the verification of the model of Markowitz efficient frontier, a method used as investment analysis. This scan is used Matlab to obtain the set (or border) efficient portfolios. Once verified such data, there will be a critique of the Markowitz model as a quadratic programming and more coherent risk measures currently studied as VaR and CVaR minimizing the expected error, approaching our studies of current research. It is found that such studies have much to be explored, since there are many discussions about how effectively measure risk investments such as its characteristic and behavior, using a time series and volatility

Controle ativo de vibrações em vigas utilizando controle feedforward e elementos espectrais

Pós-graduação em Engenharia Mecânica - FEB

Estimação do número de internações por doenças respiratórias utilizando lógica fuzzy tipo-2 intervalar

In this work was developed a fuzzy computational model type-2 predictive interval, using the software of the type-2 fuzzy MATLAB toolbox, the final idea is to estimate the number of hospitalizations of patients with respiratory diseases. The interest in the creation of this model is to assist in decision makeshift hospital environment, where there are no medical or professional equipment available to provide the care that the population need. It began working with the study of fuzzy logic, the fuzzy inference system and fuzzy toolbox. Through a real database provided by the Departamento de Informática do Sistema Único de Saúde (DATASUS) and Companhia de Tecnologia de Saneamento Básico (CETESB), was possible to start the model. The analyzed database is composed of the number of patients admitted with respiratory diseases a day for the public hospital in São José dos Campos, during the year 2009 and by factors such as PM10, SO2, wind and humidity. These factors were analyzed as input variables and, through these, is possible to get the number of admissions a day, which is the output variable of the model. For data analysis we used the fuzzy control method type-2 Mamdani. In the following steps the performance developed in this work was compared with the performance of the same model using fuzzy logic type-1. Finally, the validity of the models was estimated by the ROC curve

Estudo e aplicação de diferentes métodos de resolução para problemas dinâmicos não-lineares em presença de atrito

The friction phenomena is present in mechanical systems with two surfaces that are in contact, which can cause serious damage to structures. Your understanding in many dynamic problems became the target of research due to its nonlinear behavior. It is necessary to know and thoroughly study each existing friction model found in the literature and nonlinear methods to define what will be the most appropriate to the problem in question. One of the most famous friction model is the Coulomb Friction, which is considered in the studied problems in the French research center Laboratoire de Mécanique des Structures et des Systèmes Couplés (LMSSC), where this search began. Regarding the resolution methods, the Harmonic Balance Method is generally used. To expand the knowledge about the friction models and the nonlinear methods, a study was carried out to identify and study potential methodologies that can be applied in the existing research lines in LMSSC and then obtain better final results. The identified friction models are divided into static and dynamic. Static models can be Classical Models, Karnopp Model and Armstrong Model. The dynamic models are Dahl Model, Bliman and Sorine Model and LuGre Model. Concerning about nonlinear methods, we study the Temporal Methods and Approximate Methods. The friction models analyzed with the help of Matlab software are verified from studies in the literature demonstrating the effectiveness of the developed programming

Otimização de portfólio utilizando como métricas de retorno medidas de posição central

This paper consists in applying the Modern Theory of Portfolio (MPT) using central position measurements for modeling the return on investment fund of a renowned financial institution and compare with the Medium- CVaR model. The measurement of risks and returns becomes increasingly important for investors to minimize their losses to maximize thus their possibilities of earnings, taking into account sudden change scenarios. We present concepts of investment funds used as data and research on central position measurements to determine which measure was more suitable. To assemble the Efficient Frontier of assets considering the method proposed measure of central position-CVaR position is used MatLab. Then, after getting the Frontier, it was possible to compare it with the Medium-CVaR model, already proven effective. Finally, we analyze the viability of the proposed model in portfolio management

Inserção e extração de marca d'água em imagens digitais usando a transformada wavelet

Pós-graduação em Engenharia Elétrica - FEIS

Método primal-dual previsor-corretor de pontos interiores e exteriores com estratégias de correção de inércia e suavização hiperbólica aplicado ao problema de despacho econômico com ponto de carregamento de válvula e representação da transmissão

Pós-graduação em Engenharia Elétrica - FEB

Alocação de bancos de capacitores em sistemas de distribuição radiais usando busca dispersa

Pós-graduação em Engenharia Elétrica - FEIS

Detecção e restauração de áreas sombreadas em imagens digitais de alta resolução espacial

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Alocação ótima de equipamentos SVC e TCSC na rede de transmissão de energia elétrica

Pós-graduação em Engenharia Elétrica - FEIS

Suposição de normalidade e gestão de risco: uma aplicação do var paramétrico via teste de aderência

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Ergonomia de tablets em uso ocupacional: atividade visual e biomecânica postural sob a influência de ofuscamentos reflexivos causados pela iluminação

Pós-graduação em Design - FAAC

Estimação de parâmetros de linhas de transmissão utilizando técnicas de decomposição modal: Aplicação em linhas com plano de simetria vertical

Pós-graduação em Engenharia Elétrica - FEIS