PCA Tomography: how to extract information from data cubes

Astronomy has evolved almost exclusively by the use of spectroscopic and imaging techniques, operated separately. With the development of modern technologies, it is possible to obtain data cubes in which one combines both techniques simultaneously, producing images with spectral resolution. To extract information from them can be quite complex, and hence the development of new methods of data analysis is desirable. We present a method of analysis of data cube (data from single field observations, containing two spatial and one spectral dimension) that uses Principal Component Analysis (PCA) to express the data in the form of reduced dimensionality, facilitating efficient information extraction from very large data sets. PCA transforms the system of correlated coordinates into a system of uncorrelated coordinates ordered by principal components of decreasing variance. The new coordinates are referred to as eigenvectors, and the projections of the data on to these coordinates produce images we will call tomograms. The association of the tomograms (images) to eigenvectors (spectra) is important for the interpretation of both. The eigenvectors are mutually orthogonal, and this information is fundamental for their handling and interpretation. When the data cube shows objects that present uncorrelated physical phenomena, the eigenvector`s orthogonality may be instrumental in separating and identifying them. By handling eigenvectors and tomograms, one can enhance features, extract noise, compress data, extract spectra, etc. We applied the method, for illustration purpose only, to the central region of the low ionization nuclear emission region (LINER) galaxy NGC 4736, and demonstrate that it has a type 1 active nucleus, not known before. Furthermore, we show that it is displaced from the centre of its stellar bulge.

Controle aplicado a poços com método de elevação e bombeio centrífugo submerso

The Electrical Submersible Pumping is an artificial lift method for oil wells employed in onshore and offshore areas. The economic revenue of the petroleum production in a well depends on the oil flow and the availability of lifting equipment. The fewer the failures, the lower the revenue shortfall and costs to repair it. The frequency with which failures occur depends on the operating conditions to which the pumps are submitted. In high-productivity offshore wells monitoring is done by operators with engineering support 24h/day, which is not economically viable for the land areas. In this context, the automation of onshore wells has clear economic advantages. This work proposes a system capable of automatically control the operation of electrical submersible pumps, installed in oil wells, by an adjustment at the electric motor rotation based on signals provided by sensors installed on the surface and subsurface, keeping the pump operating within the recommended range, closest to the well s potential. Techniques are developed to estimate unmeasured variables, enabling the automation of wells that do not have all the required sensors. The automatic adjustment, according to an algorithm that runs on a programmable logic controller maintains the flow and submergence within acceptable parameters avoiding undesirable operating conditions, as the gas interference and high engine temperature, without need to resort to stopping the engine, which would reduce the its useful life. The control strategy described, based on modeling of physical phenomena and operational experience reported in literature, is materialized in terms of a fuzzy controller based on rules, and all generated information can be accompanied by a supervisory system

Abordando o ensino de óptica através da construção de telescópios

A proposta deste trabalho é a construção artesanal de um telescópio refletor do tipo Newtoniano relacionando conteúdos abordados na disciplina de óptica, como a formação de imagens em lentes e espelhos, aberrações esféricas e cromáticas, interferência e difração, com cada fase do processo de construção. Com o aparelho construído é possível abordar a fotografia lunar e planetária com alta resolução e sua utilização por alunos do curso de Licenciatura em Física já demonstra ser um grande incentivo à contemplação do céu e à compreensão de muitos fenômenos físicos, com ocorrências de eclipses, formação das marés, estações do ano, etc, que geralmente são pouco abordados nas escolas de Ensino Fundamental e Médio. de acordo com diagnóstico realizado pelos alunos de graduação em algumas escolas do município de Bauru, verificou-se que a única abordagem de astronomia é apenas em relação ao sistema solar, especificamente órbitas planetárias, nas disciplinas de Física ou Geografia. Além do telescópio, a utilização de animações produzidas por alunos de graduação também pode ser considerada como uma ferramenta eficiente no ensino de astronomia, principalmente para alunos de Ensino Fundamental.

Influence of compression forces on tablets disintegration by AC Biosusceptometry

Analysis of physical phenomena that occurs during tablet disintegration has been studied by several experimental approaches; however none of them satisfactorily describe this process. The aim of this study was to investigate the influence of compression force on the tablets by associating the AC Biosusceptometry with consolidated methods in order to validate the biomagnetic technique as a tool for quality control in pharmaceutical processes.Tablets obtained at five compression levels were submitted to mechanical properties tests. For uncoated tablets, water uptake and disintegration force measurements were performed in order to compare with magnetic data. For coated tablets, magnetic measurements were carried out to establish a relationship between physical parameters of the disintegration process. According to the results, differences between the compression levels were found for water uptake, force development and magnetic area variation measurements. ACB method was able to estimate the disintegration properties as well as the kinetics of disintegration process for uncoated and coated tablets. This study provided a new approach for in vitro investigation and validated this biomagnetic technique as a tool for quality control for pharmaceutical industry. Moreover, using ACB will also be possible to test these parameters in humans allowing to establish an in vitro/in vivo correlation (IVIVC). (C) 2007 Elsevier B.V. All rights reserved.

MATHEMATICA notebook for computing tetrahedral finite element shape functions and matrices for the Helmholtz equation

A MATHEMATICA notebook to compute the elements of the matrices which arise in the solution of the Helmholtz equation by the finite element method (nodal approximation) for tetrahedral elements of any approximation order is presented. The results of the notebook enable a fast computational implementation of finite element codes for high order simplex 3D elements reducing the overheads due to implementation and test of the complex mathematical expressions obtained from the analytical integrations. These matrices can be used in a large number of applications related to physical phenomena described by the Poisson, Laplace and Schrodinger equations with anisotropic physical properties.

PEGylation of SPIONs by polycondensation reactions: A new strategy to improve colloidal stability in biological media

In this study, we report on a new route of PEGylation of superparamagnetic iron oxide nanoparticles (SPIONs) by polycondensation reaction with carboxylate groups. Structural and magnetic characterizations were performed by X-ray diffractometry (XRD), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and vibrating sample magnetometry (VSM). The XRD confirmed the spinel structure with a crystallite average diameter in the range of 3.5-4.1 nm in good agreement with the average diameter obtained by TEM (4.60-4.97 nm). The TGA data indicate the presence of PEG attached onto the SPIONs' surface. The SPIONs were superparamagnetic at room temperature with saturation magnetization (M S) from 36.7 to 54.1 emu/g. The colloidal stability of citrate- and PEG-coated SPIONs was evaluated by means of dynamic light scattering measurements as a function of pH, ionic strength, and nature of dispersion media (phosphate buffer and cell culture media). Our findings demonstrated that the PEG polymer chain length plays a key role in the coagulation behavior of the Mag-PEG suspensions. The excellent colloidal stability under the extreme conditions we evaluated, such as high ionic strength, pH near the isoelectric point, and cell culture media, revealed that suspensions comprising PEG-coated SPION, with PEG of molecular weight 600 and above, present steric stabilization attributed to the polymer chains attached onto the surface of SPIONs. © 2013 Springer Science+Business Media Dordrecht.

Estudo teórico das propriedades químicas e físicas envolvendo o elemento 118

Pós-graduação em Ciência e Tecnologia de Materiais - FC

Avaliação da técnica de evaporação resistiva para a deposição de filmes finos de GaAs e compostos de GaAs com óxidos e cloretos de Er ou Yb

Pós-graduação em Ciência e Tecnologia de Materiais - FC

Analogias e metáforas no ensino de física: o discurso do professor e o discurso do aluno

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Análise numérica de um coletor solar de tubo evacuado

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Aproximações entre a obra de Júlio Verne e o ensino de física

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

A prática de ensino de física no ensino médio e o conceito de proporcionalidade: conexão fundamental na construção e (re)construção de conhecimentos

Nesta dissertação buscou-se refletir sobre as dificuldades de professores e alunos com relação ao ensino e à prendizagem de Física no ensino médio (EM). Construída à luz da Teoria Antropológica do Didático de Yves Chevallard, esta dissertação teve por objetivo apontar caminhos para a construção de nova(s) praxeologia(s) que considerem a (re)ligação/articulação dos vários conteúdos de Física, principalmente os do primeiro ano do EM, com a Matemática, evocando particularmente os conceitos de proporcionalidade e a regra de três algebrizada, para auxiliar na compreensão dos fenômenos físicos observáveis no dia-a-dia. Por meio de entrevista semi estruturada com 5 (cinco) professores que lecionam Física no ensino médio, em São Miguel do Guamá, estado do Pará, buscou-se entender, que tipo de relação estes estabeleciam entre a Física e os conceitos de proporcionalidade e destes com os fenômenos físicos. Por meio da análise das entrevistas constatou-se que a articulação entre a Física e a Matemática, com a intenção de compreender os fenômenos físicos, não era comum na prática de ensino dos professores de Física no ensino médio.

Interações modais não ressonantes em vigas cantilever flexíveis

Pós-graduação em Engenharia Mecânica - FEG

Métrica para definição de pontos estáveis utilizando-se da Análise de Robustez no posicionamento por ponto preciso

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Análise das relações entre parâmetros geolétricos e vazões para o aquífero livre de Caçapava do Sul - RS

The geophysical methods may be employed in aquifer system studies, as determination of groundwater level, soil/rock contact, beyond estimative of the aquifer thickness horizon. The geoeletric methods are particularly relevant in evaluations of the oilfields systems, due to directs relations between porosity and electrical resistivity, which allow inferences about oil and gas production. The indirect estimative of the productions in free aquifers system is something complex before of the diverse variables responsible for factors or physical phenomena, as clays minerals, which conditioned the physical parameters by electric geophysical methods. This paper present analyzed correlation among electrical resistivity, chargeability and direct measure flow in shallow wells, for determination of statistical relationships between parameters and evaluation of the geological constraints evolved. The study count with the 23 shallow wells located in free aquifer, constituted by alteration materials of the granites localized in Caçapava do Sul (RS). The geophysical data are acquired by vertical electric sounding in Schlumberger array. The correlations between electrical resistivity and flow, chargeability and flow, thickness of the soil/saprolite and flow indicated relationships between physical and hydrogeologic parameters, with variations conditioned by factors as porosity, permeability, besides intrinsic geological heterogeneities such soil variable thickness and rock fragments with several alteration degrees.