Avaliação cinética e potencial do Nb2O5 obtido a partir de um complexo de nióbio para formação do oleato de metila através da reação de esterificação do ácido oleico

Among the heterogeneous catalysts materials made from niobium show up as an alternative to meet the demand of catalysts for biodiesel production. This study aims to evaluate the potential of a heterogeneous catalyst derived from a complex of niobium in the reaction of methyl esterification of oleic acid. The catalyst was synthesized after calcination at different temperatures of a niobium complex ((NH4)3[NbO(C2O4)3].H2O) generating a niobium oxide nanostructure with a different commercial niobium oxide used to synthesize the complex. The commercial niobium oxide, the complex niobium and niobium catalyst were characterized by thermogravimetry (TG and DTA), surface area analysis (BET), scanning electron microscopy (SEM) and X-ray diffraction (XRD), showing the catalyst has researched morphological and crystallographic indicating a catalytic potential higher than that of commercial niobium oxide characteristics. Factorial with central composite design point, with three factors (calcination temperature, molar ratio of alcohol/oleic acid and mass percentage of catalyst) was performed. Noting that the optimal experimental point was given by the complex calcination temperature of 600°C, a molar ratio alcohol/oleic acid of 3.007/1 and the catalyst mass percentage of 7.998%, with a conversion of 22.44% oleic acid in methyl oleate to 60 min of reaction. We performed a composite linear and quadratic regression to determine an optimal statistical point of the reaction, the temperature of calcination of the complex at 450°C, the molar ratio of alcohol/oleic acid 3.3408/1 and mass percentage of catalyst of 7.6833% . Kinetic modeling to estimate parameters for heterogeneous catalysis it set well the experimental results with a final conversion of 85.01% with 42.38% of catalyst and without catalyst at 240 min reaction was performed. Allowing to evaluate the catalyst catalytic studied has the potential to be used in biodiesel production

Migração e seletividade na região nordeste: um estudo a partir dos dados do censo demográfico de 2010

The aim of this study is to analyze the effect of migration on the income differential between northeastern migrants and nonmigrants and there by verify that the immigrants make up a group or not positively selected. The assumption that will be tested is that the presence of these immigrants affects income inequality in the region receptor, which may explain part of the high-stopping inequality in the Brazilian Northeast. The study is based on the literature selectivity migration introduced by Roy (1951), Borjas (1987) and Chiswick (1999). Does the estimated wage equation Mincer (1974) through the method of OLS, using information from the microdata sample of the 2010 Census, the Brazilian Institute of Geography and Statistics (IBGE). The results which correspond to the comparison of socioeconomic profile, showed that immigrants are more qualified and, on average, better paid than non-migrants. With the estimation of the model, it was found that, keeping all other variables constant, the income that immigrants earn is 14.43% higher than that of non-migrants. Thus, there was existence of positive selectivity in migration directed to the Northeast

Caracterização estatística de processos sísmicos via Distribuição Generalizada de Pareto. Estudo de caso: João Câmara-RN

The work is to make a brief discussion of methods to estimate the parameters of the Generalized Pareto distribution (GPD). Being addressed the following techniques: Moments (moments), Maximum Likelihood (MLE), Biased Probability Weighted Moments (PWMB), Unbiased Probability Weighted Moments (PWMU), Mean Power Density Divergence (MDPD), Median (MED), Pickands (PICKANDS), Maximum Penalized Likelihood (MPLE), Maximum Goodness-of-fit (MGF) and the Maximum Entropy (POME) technique, the focus of this manuscript. By way of illustration adjustments were made for the Generalized Pareto distribution, for a sequence of earthquakes intraplacas which occurred in the city of João Câmara in the northeastern region of Brazil, which was monitored continuously for two years (1987 and 1988). It was found that the MLE and POME were the most efficient methods, giving them basically mean squared errors. Based on the threshold of 1.5 degrees was estimated the seismic risk for the city, and estimated the level of return to earthquakes of intensity 1.5°, 2.0°, 2.5°, 3.0° and the most intense earthquake never registered in the city, which occurred in November 1986 with magnitude of about 5.2º

Não vício assintótico, consistência forte e uniformemente forte de estimadores do tipo núcleo para dados direcionais sobre uma esfera unitária k-dimensional

In this work we studied the asymptotic unbiasedness, the strong and the uniform strong consistencies of a class of kernel estimators fn as an estimator of the density function f taking values on a k-dimensional sphere

Estimadores do tipo núcleo para Variávei s I.I.D. com espaço de estados geral

In this work, the paper of Campos and Dorea [3] was detailed. In that article a Kernel Estimator was applied to a sequence of random variables with general state space, which were independent and identicaly distributed. In chapter 2, the estimator´s properties such as asymptotic unbiasedness, consistency in quadratic mean, strong consistency and asymptotic normality were verified. In chapter 3, using R software, numerical experiments were developed in order to give a visual idea of the estimate process

Projeto e implementação de uma plataforma MP-SoC usando SystemC

This work presents the concept, design and implementation of a MP-SoC platform, named STORM (MP-SoC DirecTory-Based PlatfORM). Currently the platform is composed of the following modules: SPARC V8 processor, GPOP processor, Cache module, Memory module, Directory module and two different modles of Network-on-Chip, NoCX4 and Obese Tree. All modules were implemented using SystemC, simulated and validated, individually or in group. The modules description is presented in details. For programming the platform in C it was implemented a SPARC assembler, fully compatible with gcc s generated assembly code. For the parallel programming it was implemented a library for mutex managing, using the due assembler s support. A total of 10 simulations of increasing complexity are presented for the validation of the presented concepts. The simulations include real parallel applications, such as matrix multiplication, Mergesort, KMP, Motion Estimation and DCT 2D

Estudo teórico-bioclimático da potencialidade de desenvolvimento do Aedes aegypti no estado do Rio Grande do Norte

In the current climate of global public health there is the emergence of urban dengue, a disease regarded as acute infectious fever. The disease annually, has affected millions of people worldwide, mostly in the range of the intertropical globe. The disease's main vector in urban areas, the Aedes aegypti mosquito. Recent studies indicate that the distribution of the insect vector of dengue in the geographical area is directly tied to the behavior of environmental restrictions that area, especially among those, the air temperature and relative humidity. From that context, the work aims to estimate and spatializing, monthly, for each municipality in the state of Rio Grande do Norte, the potential of biophysical conditions conducive to the development of Aedes aegypti. Yet, made use of the following methodology: collection of epidemiological data and climatological, Normal climatological, descriptive statistics (measures of central tendency and scatter), uniform distribution, estimation geostatistics and sufer program, version 8.0. The results flagged for a behavior very heterogeneous, both in space and in time, in the case of the potential of biophysical conditions conducive to the development of Aedes aegypti in the state of Rio Grande do Norte. Still, he noted that there is a tendency for lifting the potential of development for the entire state, from the month of January, ending in the month of April mainly in central and western portions of the state. By contrast, there is the permanence of increased potential for development in the eastern portion of the state. The latter record maximum potential in the month of July, resulting probability of greater than 70% have been favorable conditions for the development of Aedes aegypti in that area. In the period between the months of August to December, it is small potential for development of Aedes aegypti in all parts of the state

Controlador adaptativo backstepping a estrutura variável

Neste trabalho, um controlador adaptativo backstepping a estrutura variável (Variable Structure Adaptive Backstepping Controller, VS-ABC) é apresentado para plantas monovariáveis, lineares e invariantes no tempo com grau relativo unitário. Ao invés das tradicionais leis integrais para estimação dos parâmetros da planta, leis chaveadas são utilizadas com o objetivo de aumentar a robustez em relação a incertezas paramétricas e distúrbios externos, bem como melhorar o desempenho transitório do sistema. Adicionalmente, o projeto do novo controlador é mais intuitivo quando comparado ao controlador backstepping original, uma vez que os relés introduzidos apresentam amplitudes diretamente relacionadas com os parâmetros nominais da planta. Esta nova abordagem, com uso de estrutura variável, também reduz a complexidade das implementações práticas, motivando a utilização de componentes industriais, tais como, FPGAs (Field Programmable Gate Arrays ), MCUs (Microcontrollers) e DSPs (Digital Signal Processors). Simulações preliminares para um sistema instável de primeira e segunda ordem são apresentadas de modo a corroborar os estudos. Um dos exemplos de Rohrs é ainda abordado através de simulações, para os dois cenários adaptativos: o controlador backstepping adaptativo original e o VS-ABC

Modelo de risco controlado por resseguro e desigualdades para a probabilidade de ruína

In the work reported here we present theoretical and numerical results about a Risk Model with Interest Rate and Proportional Reinsurance based on the article Inequalities for the ruin probability in a controlled discrete-time risk process by Ros ario Romera and Maikol Diasparra (see [5]). Recursive and integral equations as well as upper bounds for the Ruin Probability are given considering three di erent approaches, namely, classical Lundberg inequality, Inductive approach and Martingale approach. Density estimation techniques (non-parametrics) are used to derive upper bounds for the Ruin Probability and the algorithms used in the simulation are presented

Contribuições de modelagem de equações estruturais na análise de dados em modelos comportamentais de destino turístico

A fragilidade brasileira quanto à competitividade turística é um fato observável nos dados da Organização Mundial do Turismo. O Brasil caiu em 2011, da 45ª para a 52ª posição, apesar de liderar no atributo recursos naturais e estar colocado na 23° em recursos culturais. Assim, grandes interesses e esforços têm sido direcionados para o estudo da competitividade dos produtos e destinos turísticos. O destino turístico é caracterizado por um conjunto complexo e articulado de fatores tangíveis e intangíveis, apresentando alta complexidade, dados de elevada dimensionalidade, não linearidade e comportamento dinâmico, tornando-se difícil a modelagem desses processos por meio de abordagens baseadas em técnicas estatísticas clássicas. Esta tese investigou modelos de equações estruturais e seus algoritmos, aplicados nesta área, analisando o ciclo completo de análise de dados, em um processo confirmatório no desenvolvimento e avaliação de um modelo holístico da satisfação do turista; na validação da estrutura do modelo de medida e do modelo estrutural, por meio de testes de invariância de múltiplos grupos; na análise comparativa dos métodos de estimação MLE, GLS e ULS para a modelagem da satisfação e na realização de segmentação de mercado no setor de destino turístico utilizando mapas auto-organizáveis de Kohonen e sua validação com modelagem de equações estruturais. Aplicações foram feitas em análises de dados no setor de turismo, principal indústria de serviços do Estado do Rio Grande do Norte, tendo sido, teoricamente desenvolvidos e testados empiricamente, modelos de equações estruturais em padrões comportamentais de destino turístico. Os resultados do estudo empírico se basearam em pesquisas com a técnica de amostragem aleatória sistemática, efetuadas em Natal-RN, entre Janeiro e Março de 2013 e forneceram evidências sustentáveis de que o modelo teórico proposto é satisfatório, com elevada capacidade explicativa e preditiva, sendo a satisfação o antecedente mais importante da lealdade no destino. Além disso, a satisfação é mediadora entre a geração da motivação da viagem e a lealdade do destino e que os turistas buscam primeiro à satisfação com a qualidade dos serviços de turismo e, posteriormente, com os aspectos que influenciam a lealdade. Contribuições acadêmicas e gerenciais são mostradas e sugestões de estudo são dadas para trabalhos futuros.

Modelagem e simulação da solubilidade de sais em sistemas aquosos com Monoetilenoglicol

Primary processing of natural gas platforms as Mexilhão Field (PMXL-1 ) in the Santos Basin, where monoethylene glycol (MEG) has been used to inhibit the formation of hydrates, present operational problems caused by salt scale in the recovery unit of MEG. Bibliographic search and data analysis of salt solubility in mixed solvents, namely water and MEG, indicate that experimental reports are available to a relatively restricted number of ionic species present in the produced water, such as NaCl and KCl. The aim of this study was to develop a method for calculating of salt solubilities in mixed solvent mixtures, in explantion, NaCl or KCl in aqueous mixtures of MEG. The method of calculating extend the Pitzer model, with the approach Lorimer, for aqueous systems containing a salt and another solvent (MEG). Python language in the Integrated Development Environment (IDE) Eclipse was used in the creation of the computational applications. The results indicate the feasibility of the proposed calculation method for a systematic series of salt (NaCl or KCl) solubility data in aqueous mixtures of MEG at various temperatures. Moreover, the application of the developed tool in Python has proven to be suitable for parameter estimation and simulation purposes

Contribuições ao estudo de modelagem de equações estruturais na avaliação da satisfação do cliente de serviços de comunicações móveis

No mercado de telecomunicações as transformações tecnológicas das últimas décadas aliaram-se a um cenário formado por empresas de alta tecnologia que caracterizam o setor de comunicações móveis pessoais em todo mundo. Neste contexto, as empresas deste setor preocupam-se cada vez mais com a competitividade, oferta de serviços, área de atendimento, demanda reprimida e a lealdade do cliente. Estudos de comportamento do consumidor pesquisam a satisfação e lealdade de clientes como fatores básicos para relações bem sucedidas e duradouras com as empresas. A complexidade das relações entre variáveis na avaliação da satisfação do cliente em comunicações móveis pode ser adequadamente pesquisada com a utilização de métodos estatísticos multivariados. Essa tese analisou as relações causais envolvendo os antecedentes e consequentes associados à satisfação do cliente, no segmento de comunicações móveis, bem como desenvolveu e validou um modelo comportamental do cliente no uso deste serviço, buscando explicar as relações entre os construtos envolvidos: satisfação, qualidade dos serviços, valor percebido, imagem da marca, lealdade e reclamação. Foi estabelecida uma ampla base teórica para avaliar a importância estratégica do modelo que relaciona a influência na satisfação do serviço com as percepções dos clientes e avaliada a precisão deste modelo, por meio de uma análise comparativa a utilização de três métodos de estimação dos seus parâmetros, MLE, GLS, e ULS, com o emprego de modelagem de equações estruturais. Foram feitas aplicações em análises de dados, sendo testada e avaliada empiricamente, a influência do gênero na satisfação do cliente deste setor, além de uma segmentação de mercado utilizando mapas auto-organizáveis e a correspondente validação deste processo, com modelagem de equações estruturais.Os resultados do estudo empírico produziram uma boa qualidade de ajustamento para o modelo teórico proposto, com evidências do estabelecimento de uma adequada capacidade explicativa e preditiva, destacando-se a relevância da relação causal entre a satisfação e lealdade, em consonância com diversos estudos realizados para os mercados de comunicações móveis.

Contribuições à estratégia de controle sem detecção de harmônicos aplicada a um filtro ativo de potência paralelo

The conventional control schemes applied to Shunt Active Power Filters (SAPF) are Harmonic extractor-based strategies (HEBSs) because their effectiveness depends on how quickly and accurately the harmonic components of the nonlinear loads are identified. The SAPF can be also implemented without the use of the load harmonic extractors. In this case, the harmonic compensating term is obtained from the system active power balance. These systems can be considered as balanced-energy-based schemes (BEBSs) and their performance depends on how fast the system reaches the equilibrium state. In this case, the phase currents of the power grid are indirectly regulated by double sequence controllers with two degrees of freedom, where the internal model principle is employed to avoid reference frame transformation. Additionally the DSC controller presents robustness when the SAPF is operating under unbalanced conditions. Furthermore, SAPF implemented without harmonic detection schemes compensate simultaneously harmonic distortion and reactive power of the load. Their compensation capabilities, however, are limited by the SAPF power converter rating. Such a restriction can be minimized if the level of the reactive power correction is managed. In this work an estimation scheme for determining the filter currents is introduced to manage the compensation of reactive power. Experimental results are shown for demonstrating the performance of the proposed SAPF system.

An augmented reality pipeline to create scenes with coherent illumination using textured cuboids

Shadows and illumination play an important role when generating a realistic scene in computer graphics. Most of the Augmented Reality (AR) systems track markers placed in a real scene and retrieve their position and orientation to serve as a frame of reference for added computer generated content, thereby producing an augmented scene. Realistic depiction of augmented content with coherent visual cues is a desired goal in many AR applications. However, rendering an augmented scene with realistic illumination is a complex task. Many existent approaches rely on a non automated pre-processing phase to retrieve illumination parameters from the scene. Other techniques rely on specific markers that contain light probes to perform environment lighting estimation. This study aims at designing a method to create AR applications with coherent illumination and shadows, using a textured cuboid marker, that does not require a training phase to provide lighting information. Such marker may be easily found in common environments: most of product packaging satisfies such characteristics. Thus, we propose a way to estimate a directional light configuration using multiple texture tracking to render AR scenes in a realistic fashion. We also propose a novel feature descriptor that is used to perform multiple texture tracking. Our descriptor is an extension of the binary descriptor, named discrete descriptor, and outperforms current state-of-the-art methods in speed, while maintaining their accuracy.

Mortalidade segundo sua causa de morte e seus determinantes: uma análise para as capitais brasileiras e municípios do nordeste do Brasil, 2000 e 2010

This dissertation considered the development of two papers, both related to mortality in Brazil. In the first article, "The context of mortality according to the three broad groups of causes of death in Brazilian capitals, 2000 and 2010", the objective was to analyze the mortality rate according to the three major groups of causes of death in Brazilian capitals. In the second article, "Typology and characteristics of mortality from external causes in the municipalities in the Northeast of Brazil, 2000 and 2010", it was built up a typology for the Northeastern municipalities taking into account information on mortality from external causes and a set of indicators related to socioeconomic, demographic, and infrastructure aspects of such municipalities, both articles for the years 2000 and 2010. Thus, we used data from the Mortality Information System of the Ministry of Health. Furthermore, it was used information from the Demographic Census for those years. The variables relating to socioeconomic and demographic conditions used in this study were those available on the home page of the United Nations Program for Development. The variables relating to socioeconomic and demographic conditions used in this study were those available on the home page of the United Nations Program for Development. Was used in Article 1 the pro-rata distribution method to accomplish the redistribution of ill-defined causes. Moreover, made use of the technique of cluster analysis with the aim of grouping the capital that had proportions of deaths from ill-defined causes similar to each other. Already in Section 2, we used the technique of Empirical Bayesian estimation; spatial statistics technique; and finally, the Grade of Membership method to find types of municipalities from information on mortality from external causes associated with socioeconomic, demographic and infrastructure variables. As the main results, it stands out in Article 1, in relation to data quality, we observed the formation of four groups of similar capital between themselves, as the proportion of illdefined causes. Regarding the behavior of mortality, according to the three major groups of causes of death, it was noted both for 2000 and for 2010 the prevalence of deaths from noncommunicable diseases for both sexes, although the reduction was identified rates in some of the capitals. Communicable diseases stood out as the second cause of death among women. Also, we found that deaths due to external causes are responsible for the second cause of death among men, as well as presenting an increase among women. As for the Article 2, stands out, in general, not just an extension of mortality from external causes in the municipalities, as well as an enlargement of the configurator stain existence of external cause deaths for the whole area of Northeast. Regarding the typology of municipalities, three vi extreme profiles were buit: the profile 1, which comprises municipalities with high rates of mortality from external causes and the best social indicators; the profile 2, that was composed of municipalities that are characterized by having low mortality rates from external causes and the lowest social indicators; and the profile 3, that brings together municipalities with intermediate mortality rates and median values considered in relation to social indicators. Although we have not seen changes in the characteristics of the profiles, we observed an increase in the proportion of municipalities that belong to the extreme profile 3, taking into account the mixed profiles.