Conselho Nacional de Desenvolvimento Científico e Tecnológico / A relação entre porosidade e permeabilidade desperta o interesse de pesquisadores e engenheiros por causa de suas diversas aplicações. Tais como na utilização de filtros, materiais pouco permeáveis, reservatórios naturais, etc. Ao longo do século XX, diversos trabalhos propondo tal relação foram apresentados na literatura e grande parte desses trabalhos desenvolvem modelos baseados na equação clássica de Kozeny-Carman. Nesta dissertação, propomos um modelo mais robusto que a formulação clássica de Kozeny-Carman, ou seja, que não apresenta as limitações dessa equação clássica. Além disso, um estudo baseado na Teoria dos Meios Fractais indica que o modelo estudado, nesta dissertação, generaliza diversas equações que fornecem a relação entre porosidade e permeabilidade. Por fim, será mostrado que o modelo proposto é capaz de descrever a relação entre porosidade e permeabilidade de diversos materiais porosos de natureza fractal. / The relationship between porosity and permeability attracts the attention of researchers and engineers because of their various applications. Such as in utilization of filters, waterproof materials, natural reservoirs, for example.Throughout the twentieth century, several works proposed in the literature they study the relation porosity-permeability, and much of this works they develop models based on the classical equation of Kozeny-Carman. In this dissertation, we propose a model more robust than the classical formulation of Kozeny-Carman, ie, that does not have the limitations of the equation classical. Furthermore, a study based on the Theory of the Media Fractals indicates that the model studied in this dissertation provide the relationship between porosity and permeability of several models presented in the literature. Finally, it will shown that the model proposed is able to describe the relationship between porosity and permeability of porous materials of various fractal nature.

Made available in DSpace on 2016-06-02T20:29:24Z (GMT). No. of bitstreams: 1 5485.pdf: 1729103 bytes, checksum: b09e1b153530a221dce99193f3506fe6 (MD5) Previous issue date: 2013-08-26 / Financiadora de Estudos e Projetos / This work has objective to show results of a didactic experience that consider the use of a dynamic geometric software in a restrict area of the Mathematic, named fractal . This study presents a great complexity and beauty in your geometric structures. Therefore, we present some fractals, in particular, the Pythagorean Tree that arouses the interest of students. For geometric constructions, we chose the GeoGebra software, based in the geometry lessons that we had in the course. Next, we explore one of the most famous theorems of the Plane Geometry, the Pythagoras Theorem, in addition of others mathematics contents, such as, counting. We also study the main trends connected to the informatics and we took advantages of the computational technology resource to assist the students with the construction and learning, including them in a new educational scenario based in the technology presence. / Este trabalho tem o objetivo de expor os resultados de uma experiência didática que envolve o uso de software de geometria dinâmica numa área restrita da Matemática, denominada fractal , a qual apresenta estruturas geométricas de grande complexidade e beleza. Para tanto, apresentamos alguns fractais, em particular, a Árvore Pitagórica, despertando o interesse dos alunos. Para as construções, escolhemos o software GeoGebra, baseado nas aulas de geometria que tivemos no curso. Em seguida, exploramos um dos teoremas mais famosos da Geometria Plana, o Teorema de Pitágoras e outros conteúdos de matemática, tais como, contagem. Estudamos as principais tendências ligadas à informática e aproveitamos os recursos da tecnologia computacional para colaborar com a construção e a aprendizagem do aluno, inserindo-o no novo cenário educacional fundado na presença da informática.

abstract: Programmable metallization cell (PMC) technology employs the mechanisms of metal ion transport in solid electrolytes (SE) and electrochemical redox reactions in order to form metallic electrodeposits. When a positive bias is applied to an anode opposite to a cathode, atoms at the anode are oxidized to ions and dissolve into the SE. Under the influence of the electric field, the ions move to the cathode and become reduced to form the electrodeposits. These electrodeposits are filamentary in nature and persistent, and since they are metallic can alter the physical characteristics of the material on which they are formed. PMCs can be used as next generation memories, radio frequency (RF) switches and physical unclonable functions (PUFs). The morphology of the filaments is impacted by the biasing conditions. Under a relatively high applied electric field, they form as dendritic elements with a low fractal dimension (FD), whereas a low electric field leads to high FD features. Ion depletion effects in the SE due to low ion diffusivity/mobility also influences the morphology by limiting the ion supply into the growing electrodeposit. Ion transport in SE is due to hopping transitions driven by drift and diffusion force. A physical model of ion hopping with Brownian motion has been proposed, in which the ion transitions are random when time window is larger than characteristic time. The random growth process of filaments in PMC adds entropy to the electrodeposition, which leads to random features in the dendritic patterns. Such patterns has extremely high information capacity due to the fractal nature of the electrodeposits. In this project, lateral-growth PMCs were fabricated, whose LRS resistance is less than 10Ω, which can be used as RF switches. Also, an array of radial-growth PMCs was fabricated, on which multiple dendrites, all with different shapes, could be grown simultaneously. Those patterns can be used as secure keys in PUFs and authentication can be performed by optical scanning. A kinetic Monte Carlo (KMC) model is developed to simulate the ion transportation in SE under electric field. The simulation results matched experimental data well that validated the ion hopping model. / Dissertation/Thesis / Doctoral Dissertation Electrical Engineering 2015

abstract: Counterfeiting of goods is a widespread epidemic that is affecting the world economy. The conventional labeling techniques are proving inadequate to thwart determined counterfeiters equipped with sophisticated technologies. There is a growing need of a secure labeling that is easy to manufacture and analyze but extremely difficult to copy. Programmable metallization cell technology operates on a principle of controllable reduction of a metal ions to an electrodeposit in a solid electrolyte by application of bias. The nature of metallic electrodeposit is unique for each instance of growth, moreover it has a treelike, bifurcating fractal structure with high information capacity. These qualities of the electrodeposit can be exploited to use it as a physical unclonable function. The secure labels made from the electrodeposits grown in radial structure can provide enhanced authentication and protection from counterfeiting and tampering. So far only microscale radial structures and electrodeposits have been fabricated which limits their use to labeling only high value items due to high cost associated with their fabrication and analysis. Therefore, there is a need for a simple recipe for fabrication of macroscale structure that does not need sophisticated lithography tools and cleanroom environment. Moreover, the growth kinetics and material characteristics of such macroscale electrodeposits need to be investigated. In this thesis, a recipe for fabrication of centimeter scale radial structure for growing Ag electrodeposits using simple fabrication techniques was proposed. Fractal analysis of an electrodeposit suggested information capacity of 1.27 x 1019. The kinetics of growth were investigated by electrical characterization of the full cell and only solid electrolyte at different temperatures. It was found that mass transport of ions is the rate limiting process in the growth. Materials and optical characterization techniques revealed that the subtle relief like structure and consequently distinct optical response of the electrodeposit provides an added layer of security. Thus, the enormous information capacity, ease of fabrication and simplicity of analysis make macroscale fractal electrodeposits grown in radial programmable metallization cells excellent candidates for application as physical unclonable functions. / Dissertation/Thesis / Masters Thesis Materials Science and Engineering 2017

Orientador: Marcos César Ferreira / Banca: Sergio dos Anjos Ferreira Pinto / Banca: Magda Adelaide Lombardo Fruehauf / Banca: Diana Sarita Hamburger / Banca: Teresa Gallotti Florenzano / Este estudo teve como propósito principal aplicar e avaliar metodologias para análise fractal da expansão de espaços urbanos metropolitanos, tendo como caso o aglomerado da região metropolitana de São Paulo, Brasil. O estudo foi realizado a partir de mapas temáticos e imagens orbitais relativos ao período 1905-2001, aos quais foram aplicados três métodos para a estimativa da dimensão fractal: densidade de preenchimento (Dd), perímetro-área (DPA) e perímetro-resolução (DPR). A partir da análise fractal dos mapas e imagens, foram avaliados a dinâmica temporal do preenchimento dos vazios urbanos e da expansão multidirecional do perímetro urbano. Os resultados mostraram que o aglomerado urbano como um todo, apresentou no período analisado, valores médios Dd (1,755) ou tendência de preenchimento das áreas centrais e diluição das periféricas; DPA (1,400) ou sinuosidade do perímetro urbano a medida em que estas áreas foram ocupadas e DPR (1,859) ou limitada organização espacial das estruturas urbanas. A análise fractal multidirecional de crescimento foi realizada em oito setores radiais de expansão urbana, cujos valores médios do parâmetro Dd no período 1905-2001 são abaixo mencionados: (I) Cantareira=1,829; (II) Zona Leste=1,898; (III) Mauá=1,848; (IV) Ipiranga=1,852; (V) Billings=1,858; (VI) Santo Amaro/Interlagos=1,848; (VII) Castelo Branco/Anhanguera=1,859 e (VIII) Anhanguera/Bandeirantes=1,863. Dentre os fatores que influenciaram o comportamento fractal destes setores, destaca-se a ocupação fragmentada pela topografia, hidrografia e restrições jurídico-ambientais nos setores I, III, IV, V, VI e VIII e, nos setores II, III, IV, VI e VII a maior densificação foi impulsionada por incentivos públicos e de infra-estrutura, que contribuíram para a concentração industrial e de serviços. / The aim of this research is to evaluate and apply fractal dimension analysis methodologies to study the growing of metropolitan areas, using thematic maps and satellite images of time series. The Sao Paulo metropolitan area it was choose as test area to calculate fractal dimension variability over 96 years time series (1905-2001). Fractal dimension of the metropolitan area as a whole and urban expansion radial sectors it was calculated using the following fractal dimension methods: occupation urban density (Dd); area-perimeter (DPA) and perimeter -scale- (DPR). The study was accomplished to thematic maps and orbital images from 1905 to 2001 that supplied information to estimate fractal dimensions from relations of density (Dd), areaperimeter and perimeter-scale (DPR). Fractal dimension of maps and images were to evaluate the time oscillation of empty urban spaces and the radial growing of urban perimeter. Over period analyzed, urban agglomeration as a whole show means values of Dd = 1.755 - a trend to fill central areas and dilution of occupation density at peripheral ones; DPA = 1.400 - related to tortuous urban boundary at time the urban peripheries were occupied; and DPR = 1.859 related to low spatial organization of urban structures. The radial growing fractal analysis was accomplished to eight urban radial sectors, whose show means values of Dd parameter over 1905-2001, as following:(I) Cantareira =1.829; (II) East Zone =1.898; (III) Máua=1.848; (IV) Ipiranga=1.852; (V) Billings=1.858; (VI) Santo Amaro/Interlagos =1.848; (VII) Castelo Branco /Anhanguera=1.859; e (VIII) Anhanguera/Bandeirantes =1.863. Among determinants factors on fractal behavior of sectors I, III, IV, V, VI e VIII, the results show the topographical, hydrographical and environment-legal constraints influenced the fragmented occupation and; for sectors II, III, IV, VI e VII... (Complete abstract, click eletronic address below). / Doutor

Les émulsions eau/eau (W/W) ont suscité un grand intérêt en raison de leur potentiel d'application dans différentes industries telles que l'agroalimentaire, les produits pharmaceutiques, les cosmétiques et les soins personnels. Le caractère particulier des émulsions W/W est leur stabilisation par ajout de particules. L’objectif de ce travail de thèse est de comprendre cet aspect en étudiant une émulsion modèle W/W à base de dextran et du poly(oxyde d'éthylène) stabilisée par des particules à base de protéines du lactosérum. Dans un premier temps, nous avons étudié l'effet de la morphologie des particules protéiques et leur partitionnement sur la stabilité des émulsions W/W. En particulier, la stabilité s’est révélée dépendre de la structure des particules quand ses derniers étaient sous forme de microgels, d’agrégats fractals ou de fibrilles. Il a été montré que la stabilité s'améliorait lorsque les particules se localiser préférentiellement dans la phase continue. Deuxièmement, nous avons étudié la gélification, des microgels et des agrégats fractals, induite en réduisant le pH entre 6,5 et 3,5 ou en ajoutant 0,3 M NaCl à pH 7,0 aussi bien quand l’excès des particules se situe dans la phase continue ou dispersée. Dans le premier cas, un réseau se formé dans la phase continue de dextran, permettant d’inhiber le crémage des gouttelettes de PEO, les agrégats fractals étant plus efficaces que les microgels. Dans le second cas, des particules protéiques denses pourraient être formées par gélification des gouttelettes de dextran dispersées. Finalement, nous avons exploré l'adsorption des protéines natives sur les particules de latex et leur capacité à stabiliser les émulsions. / Water/water (W/W) emulsions have attracted great interest recently due to their high potential for applications in different industries such as food and beverages, pharmaceutical, cosmetics and personal care. An important issue is the stabilization of W/W emulsions by adding particles. The aim of the research for this thesis was to shed light on this issue by studying a model W/W emulsion formed by mixing dextran and poly(ethylene oxide) with particles based on whey proteins. Firstly, we studied the effect of the morphology of protein particles and their partitioning on the stability of W/W emulsions. The stability was different when microgels, fractal aggregates or fibrils were added. We showed that stability improved when the particles partitioned to the continuous phase. Secondly, we investigated gelation of the fractal aggregates and microgels induced by reducing the pH between 6.5 and 3.5 or by adding 0.3M NaCl at pH 7.0 with excess particles either in the continuous or he dispersed phase. In the first case, a network was formed in the continuous dextran phase, making it possible to arrest creaming of PEO droplets, fractal aggregates being more effective than microgels. In the second case, dense protein particles could be formed by gelation of the dispersed dextran droplets. Thirdly, we explored the effect of adsorbing native proteins unto latex particles on their capacity to stabilize W/W emulsions.

Made available in DSpace on 2014-12-17T15:14:54Z (GMT). No. of bitstreams: 1 ManoelSV_DISSERT.pdf: 1448096 bytes, checksum: 866dbf446f607cd2166e9d64dab483ef (MD5) Previous issue date: 1995-07-14 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / Neste trabalho investigamos o espectro de polariton de plasmons (modos de volume e superf?cie) assim como o espectro ?ptico (reflect?ncia e transmit?ncia) em uma estrutura quasi-peri?dica, que obedece uma sequ?ncia de Cantor. O sistema quasi-peri?dico de multi-camadas de Cantor ? criado quando duas camadas diferentes, de materiais distintos A e B, s?o dispostos de acordo com a seguinte rela??o de recorr?ncia: C1 = ABA;C2= C1B2C1;...;Cn= Cn-1BnCn-1 Onde Bn ? o mesmo meio da camada B mas com diferente espessura. O aparatus experimental mais simples para medir estes espectros, consiste em posicionar a super-rede tipo Cantor na forma de um filme embebido no v?cuo. Usando o m?todo da matriz-transfer?ncia, para simplificar a ?lgebra, ? poss?vel determinar-se a rela??o de dispers?o dos polaritons (modos de superf?cie e volume), assim como as express?es te?ricas de reflect?ncia e transmit?ncia. H? uma s?rie de resultados interessantes nestes espectros, os quais discutiremos em detalhes neste trabalho

Conselho Nacional de Desenvolvimento Científico e Tecnológico / A relação entre porosidade e permeabilidade desperta o interesse de pesquisadores e engenheiros por causa de suas diversas aplicações. Tais como na utilização de filtros, materiais pouco permeáveis, reservatórios naturais, etc. Ao longo do século XX, diversos trabalhos propondo tal relação foram apresentados na literatura e grande parte desses trabalhos desenvolvem modelos baseados na equação clássica de Kozeny-Carman. Nesta dissertação, propomos um modelo mais robusto que a formulação clássica de Kozeny-Carman, ou seja, que não apresenta as limitações dessa equação clássica. Além disso, um estudo baseado na Teoria dos Meios Fractais indica que o modelo estudado, nesta dissertação, generaliza diversas equações que fornecem a relação entre porosidade e permeabilidade. Por fim, será mostrado que o modelo proposto é capaz de descrever a relação entre porosidade e permeabilidade de diversos materiais porosos de natureza fractal. / The relationship between porosity and permeability attracts the attention of researchers and engineers because of their various applications. Such as in utilization of filters, waterproof materials, natural reservoirs, for example.Throughout the twentieth century, several works proposed in the literature they study the relation porosity-permeability, and much of this works they develop models based on the classical equation of Kozeny-Carman. In this dissertation, we propose a model more robust than the classical formulation of Kozeny-Carman, ie, that does not have the limitations of the equation classical. Furthermore, a study based on the Theory of the Media Fractals indicates that the model studied in this dissertation provide the relationship between porosity and permeability of several models presented in the literature. Finally, it will shown that the model proposed is able to describe the relationship between porosity and permeability of porous materials of various fractal nature.

À l’heure de la prise de conscience de la finitude des ressources et du besoin grandissant d'énergie, la notion de développement durable doit prendre une place centrale dans l'évolution de la société. Pour atteindre ce but, il est maintenant reconnu, qu'un changement de consommation profond est nécessaire ; et ce, qu'il s'agisse de consommation énergétique, alimentaire ou de produits finis. Nous croyons que ce changement de paradigme n’est possible que si tous les acteurs avancent de concerts sur les différentes problématiques auxquelles nous sommes confrontées. Chacun à son échelle doit ainsi pouvoir prendre les décisions qui s'imposent à tous. C'est la logique qui a motivé l'outil d'exergo-graphie présenté dans le chapitre 3. Inscrit dans la lignée des diagrammes de Sankey, il permet de représenter les bilans exergétiques sous forme graphique afin d’en communiquer plus facilement les enseignements. Nous l’appliquons à deux cas d'analyses faites sur les installations de chauffage et de production d’ECS du bâtiment A de l’UPN. Pour chacune, nous étudions la possibilité d’une solution de production durable de la chaleur (PAC géothermique et solaire thermique). Après en avoir présenté les analyses, nous en dressons les représentations graphiques que nous comparons à celles du système actuel. Au préalable, le chapitre 1 introduit les concepts de base de l’analyse exergétique, approfondis dans le chapitre 2, au travers d’une modélisation des systèmes fluides statiques et dynamiques. Finalement, dans le chapitre 4, nous introduisons un modèle-jouet qui, proposant une représentation fractale de la chaleur, tente d’établir un lien conceptuel entre le comportement microscopique, statistique, du support de la chaleur, et les observables macroscopiques qui la caractérisent. / At this time of awareness of the finiteness of resources, and of increasing needs for energy, the concept of sustainable development must play a central role in the forthcoming developments of our society. To do so, it is now an accepted fact that a deep change of our consumption habits is necessary; whether it is energy, food or final goods consumption. We believe this paradigm shift is only possible if all actors face together the various issues we are dealing with. Everyone, at one own scale, must be able to make informed decision. This is the idea that leads to the exergo-graphy tool presented in chapter 3. In line with the so called Sankey diagrams, it allows to graphically represent exergy balances in order to communicate more easily on their lessons. We apply it to two analysis done on the heating and DHW installations of the building A of the UPN. For each, we investigate the possibility of a sustainable heat production solution (geothermal heat pump and solar thermal energy). After presenting the analyses, we draw their graphical representations which we then compare to those of the current system. Beforehand, the first chapter introduces the basic notions of exergetic analysis, discussed further in chapter 2, through a model for static and dynamic fluid systems. Finally, in chapter 4, we introduce a toy-model which, proposing a fractal representation of exergy, tries to establish a conceptual link between microscopic, statistical, behaviour of heat background support, and the macroscopic observables that characterize it.

nÃo hà / A anÃlise de imagens à um importante campo da visÃo computacional cujo propÃsito à extrair informaÃÃes significativas de imagens. Entre os vÃrios atributos relevantes que podem ser analisados, a textura à um dos mais importantes por ser uma fonte rica de informaÃÃes. O objetivo desta tese à desenvolver novos mÃtodos de anÃlise de textura (nÃveis de cinza e coloridas) baseados em modelos gravitacionais simplicados e caminhos mais curtos em grafos, que propiciem vetores de caracterÃsticas mais discriminativos do que os mÃtodos jà estabelecidos pela literatura. A primeira abordagem converte uma imagem em um sistema gravitacional simplificado cujo processo de colapso à explorado por meio de descritores de dimensÃo fractal e lacunaridade. A segunda abordagem converte os pixels de uma imagem em vÃrtices de um grafo ponderado nÃo-orientado e explora os caminhos mais curtos entre pares de vÃrtices em diferentes escalas e orientaÃÃes. Adicionalmente, nesta tese à proposto o estudo dessas abordagens na anÃlise de imagens de folhas de plantas para facilitar o moroso processo de taxonomia vegetal (problema este especialmente relevante para os botÃnicos) e de imagens mÃdicas para identificaÃÃo/classificaÃÃo de patologias, auxiliando o diagnÃstico mÃdico. Os experimentos sÃo realizados nas bases de imagens: Brodatz, UIUC, VisTex, USPTex, Outex, texturas foliares, parÃnquima paliÃÃdico, pap-smear e de tecido mamÃrio. Os resultados mais significativos de classificaÃÃo sÃo obtidos das bases UIUC, USPTex e parÃnquima paliÃÃdico, com taxas de acertos de 55,00%, 96,57% e 91,56% (menores taxas) obtidas pelos mÃtodos propostos, respectivamente. Essas taxas de acertos sÃo quase sempre superiores aos resultados obtidos pelos mÃtodos usados para comparaÃÃo, demonstrando que os mÃtodos propostos abrem promissoras fontes de pesquisa para os estudos de anÃlise de texturas em nÃveis de cinza e coloridas. / Image analysis is an important field of computer vision whose role is to extract significant information from images. Among several relevant attributes, texture is one of the most important because it is a rich source of information. This thesis aims to develop novel texture analysis methods (for grayscale and color images) based on simplified gravitational systems and shortest paths in graphs which provide feature vectors more discriminative than the methods already established in literature. The first approach converts an image into a simplified gravitational system whose collapse process is explored by using fractal dimension and lacunarity descriptors. The second approach converts the pixels of an image into vertices of a non-oriented weighted graph and explores the shortest paths between pairs of vertices in different scales and orientations. Additionally, this thesis proposes to apply these approaches to plant leaf identification (a relevant problem for botanists), and medical image identification/classication, increasing the confidence of medical diagnosis. The experiments are performed on the following image databases: Brodatz,UIUC, VisTex, USPTex, Outex, leaf textures, palisade parenchyma, pap-smear and breast tissues. The most significant comparison results are obtained from UIUC, USPTex and palisade parenchyma, with success rates of 55,00%, 96,57% and 91,56% (lower success rates) obtained by the proposed methods, respectively. These success rates are almost always superior to the results obtained by the methods used for comparison. This demonstrates that the proposed methods open promising sources of research in grayscale and color texture analysis.