The concept of Berry phase, since its proposition in 1984, has found numerous applications and appears in almost every branch of physics today. In this work, we study several physical effects in ferromagnetic metal materials which are manifestations of the Berry phase. We first show that when a domain wall in a ferromagnetic nanowire is undergoing precessional motion, it pumps an electromotive force which follows a universal Josephson-type relation. We discover that the integral of the electromotive force over one pumping cycle is a quantized topological invariant equal to integer multiples of h/e, which does not depend on the domain wall geometry nor its detailed dynamic evolution. In particular, when a domain wall in a nanowire is driven by a constant magnetic field, we predict that the generated electromotive force is proportional to the applied field with a simple coefficient consisting of only fundamental constants. Our theoretical prediction has been successfully confirmed by experiments. Similar effect known as spin pumping occurs in magnetic multilayer heterostructures, where a precessing free magnetic layer pumps a spin current into its adjacent normal metal layers. Based on this effect, we propose two magnetic nanodevices that can be useful in future spintronics applications: the magnetic Josephson junction and the magneto-dynamic battery. The magnetic Josephson junction has a drastic increase in resistance when the applied current exceeds a critical value determined by the magnetic anisotropy. The magneto-dynamic battery acts as a conventional charge battery in a circuit with well-defined electromotive force and internal resistance. We investigate the condition under which the power output and efficiency of the battery can be optimized. Finally we study the side jump contribution in the anomalous Hall effect of a uniformly magnetized ferromagnetic metal. The side jump contribution, although arises from disorder scattering, was believed to be independent of both the scattering strength and the disorder density. Nevertheless, we find that it has a sensitive dependence on the spin structure of the disorder potential. We therefore propose a classification scheme of disorder scattering according to their spin structures. When two or more classes of disorders are present, the value of side jump is no longer fixed but depends on the relative disorder strength between classes. Due to this competition, the side jump contribution could flow from one class dominated limit to another class dominated limit when certain system control parameter changes. Our result indicates that the magnon scattering plays a role distinct from the normal impurity scattering and the phonon scattering in the anomalous Hall effect, because they belong to different scattering classes. / text

A time-dependent two-dimensional (2D) modulation model including drifts, the solar wind tennination shock (TS) with diffusive shock acceleration and a heliosheath based on the Parker (1965) transport equation is used to study the modulation of galactic cosmic rays (GCRs) and the anomalous component of cosmic rays (ACRs) in the heliosphere. In particular, the latitude dependence of the TS compression ratio and injection efficiency of the ACRs (source strength) based on the hydrodynamic modeling results of Scherer et al. (2006) is used for the first time in a modulation model. The subsequent effects on differential intensities for both GCRs and ACRs are illustrated, comparing them to the values without a latitude dependence for these parameters. It is found that the latitude dependence of these parameters is important and that it enables an improved description of the modulation of ACRs beyond the TS. With this modeling approach (without fitting observations) to the latitude dependence of the two parameters, it is possible to obtain a TS spectrum for ACRs at a polar angle of B = 55" that qualitatively approximates the main features of the Voyager 1 observations. This positive result has to be investigated further. Additionally, it is shown that the enhancement of the cosmic ray intensity just below the cut-off energy found for the ACR at the TS in an A < 0 magnetic polarity cycle in the equatorial plane with the latitude independent scenario, disappears in this region when the latitude dependence of the compression ratio and injection efficiency is assumed. Subsequent effects of these scenarios are illustrated on the global anisotropy vector of both GCRs and ACRs as the main theme of this work. For this purpose the radial and latitudinal gradients for GCRs and ACRs were accurately computed. The radial and latitudinal anisotropy components were then computed as a function of energy, radial distance and polar angle. It is also the first time that the anisotropy vector is comprehensively calculated in such a global approach to cosmic ray modeling in the heliosphere, in particular for ACRs. It is shown that the anisotropy vector inside (up-stream) and outside (down-stream) the TS behaves in a complicated way, so care must be taken in interpreting it. It is found that the latitude dependence of the two mentioned parameters can alter the direction (sign) of the anisotropy vector. Its behaviour beyond the TS is markedly different from inside the TS, mainly because of the slower solar wind velocity, with less dependence on the magnetic polarity cycles. / Thesis (M.Sc. (Physics))--North-West University, Potchefstroom Campus, 2007.

A time-dependent two-dimensional (2D) modulation model including drifts, the solar wind tennination shock (TS) with diffusive shock acceleration and a heliosheath based on the Parker (1965) transport equation is used to study the modulation of galactic cosmic rays (GCRs) and the anomalous component of cosmic rays (ACRs) in the heliosphere. In particular, the latitude dependence of the TS compression ratio and injection efficiency of the ACRs (source strength) based on the hydrodynamic modeling results of Scherer et al. (2006) is used for the first time in a modulation model. The subsequent effects on differential intensities for both GCRs and ACRs are illustrated, comparing them to the values without a latitude dependence for these parameters. It is found that the latitude dependence of these parameters is important and that it enables an improved description of the modulation of ACRs beyond the TS. With this modeling approach (without fitting observations) to the latitude dependence of the two parameters, it is possible to obtain a TS spectrum for ACRs at a polar angle of B = 55" that qualitatively approximates the main features of the Voyager 1 observations. This positive result has to be investigated further. Additionally, it is shown that the enhancement of the cosmic ray intensity just below the cut-off energy found for the ACR at the TS in an A < 0 magnetic polarity cycle in the equatorial plane with the latitude independent scenario, disappears in this region when the latitude dependence of the compression ratio and injection efficiency is assumed. Subsequent effects of these scenarios are illustrated on the global anisotropy vector of both GCRs and ACRs as the main theme of this work. For this purpose the radial and latitudinal gradients for GCRs and ACRs were accurately computed. The radial and latitudinal anisotropy components were then computed as a function of energy, radial distance and polar angle. It is also the first time that the anisotropy vector is comprehensively calculated in such a global approach to cosmic ray modeling in the heliosphere, in particular for ACRs. It is shown that the anisotropy vector inside (up-stream) and outside (down-stream) the TS behaves in a complicated way, so care must be taken in interpreting it. It is found that the latitude dependence of the two mentioned parameters can alter the direction (sign) of the anisotropy vector. Its behaviour beyond the TS is markedly different from inside the TS, mainly because of the slower solar wind velocity, with less dependence on the magnetic polarity cycles. / Thesis (M.Sc. (Physics))--North-West University, Potchefstroom Campus, 2007.

Reactive transport models are essential tools for predicting contaminant fate and transport in the subsurface and for designing effective remediation strategies. Sound understanding of subsurface mixing in heterogeneous porous media is the key for the realistic modeling of reactive transport. This dissertation aims to investigate the extent of mixing and improve upscaling effective macroscopic models for mixing-controlled reactive transport in connected heterogeneous formations, which usually exhibit strongly anomalous transport behavior. In this research, a novel approach is developed for an accurate geostatistical characterization of connected heterogeneous formations transformed from Gaussian random fields. Numerical experiments are conducted in such heterogeneous fields with different connectivity to investigate the performance of macroscopic mean transport models for simulating mixing-controlled reactive transport. Results show that good characterization of anomalous transport of a conservative tracer does not necessarily mean that the models may characterize mixing well and that, consequently, it is questionable that the models capable of characterizing anomalous transport behavior of a conservative tracer are appropriate for simulating mixing-controlled reactive transport. In connected heterogeneous fields with large hydraulic conductivity variances, macroscopic mean models ignoring concentration variations yield good prediction, while in fields with intermediate conductivity variances, the models must consider both the mean concentration and concentration variations, which are very difficult to evaluate both theoretically and experimentally. An innovative and practical approach is developed by combining mean conservative and reactive breakthrough curves for estimating concentration variations, which can be subsequently used by variance transport models for prediction. Furthermore, a new macroscopic framework based on the dual-permeability conceptualization is developed for describing both mean and concentration variation for mixing-controlled reactive transport. The developed approach and models are validated by numerical and laboratory visualization experiments. In particular, the new dual-permeability model demonstrates significant improvement for simulating mixing-controlled reactive transport in heterogeneous media with intermediate conductivity variances. Overall, results, approaches and models from this dissertation advance the understanding of subsurface mixing in anomalous transport and significantly improve the predictive ability for modeling mixing-controlled reactive transport in connected heterogeneous media.

No description available.

Ce travail de thèse a pour objectif d'étudier les rôles de la taille, de la composition et de la cinétique de croissance sur la morphologie, la structure, et l'état de mélange de l'argent et du cobalt dans des nanoparticules bimétalliques supportées AgCo. Dans ce but, des mesures in-situ et en temps réel par diffusion des rayons X aux petits et aux grands angles en géométrie d'incidence rasante, et en condition anomale, ont été effectuées au cours de la croissance des nanoparticules AgCo dans des conditions de dépôt simultané ou successif des métaux. Des recuits ont ensuite été réalisés afin d'étudier la stabilité des structures obtenues à température ambiante, et d'observer d'éventuelles transitions activées thermiquement. Pour l'ensemble des modes de dépôt, les nanoparticules (dans une gamme de taille comprise entre 2 et 7nm) présentent une configuration chimique ségrégée. Pour des dépôts successifs de Co puis d'Ag, les nanoparticules sont constituées d'un (ou plusieurs) domaine(s) d'Ag juxtaposé(s) à un domaine de Co, tandis que pour un dépôt d'Ag puis de Co les particules présentent une configuration de type coeur-coquille (Co-Ag). Pour les dépôts simultanés, la configuration cœur-coquille est obtenue à très faible composition en Ag (< ou =20%), au-delà la configuration multidomaines monométalliques est observée. Quelle que soit la configuration initiale, le recuit conduit à une séparation de phase des métaux sous forme de particules Janus et à des réorganisations structurales. / The aim of this work is to study the role of size, composition and growth kinetic conditions on the morphology, the structure and the chemical configuration of AgCo bimetallic supported nanoparticles. Thus, in-situ and in real-time anomalous grazing incidence small and wide angle X-ray scattering measurements were performed during AgCo nanoparticles growth. Two types of growth conditions were studied : simultaneous or successive deposition of the two metals. Samples were also annealed to study the stability of the structures observed at room temperature, and to investigate if structural transitions occur due to thermal activation. For all kind of deposition modes, the nanoparticles (in a size range between 2 and 7 nm) exhibit a segregated chemical configuration. For the deposition of Co followed by Ag deposition, the nanoparticles are constituted of one (or several) Ag domain(s) juxtaposed with a Co domain, whereas for Ag deposition followed by Co deposition, the nanoparticles present a (Co-Ag) core-shell configuration. For simultaneous depositions and Ag poor compositions (< or =20%), the core-shell configuration is obtained. For richer compositions, the multidomain configuration is observed. Whatever the initial configuration, annealing leads to a phase separation of the two metals towards Janus particles and some structural reorganizations occur.

Estuda as experiências anômalas (EAs), as quais podem ser definidas como incomuns e irregulares, ainda que vivenciadas por uma grande parcela da população. Dentre a variedade de EAs, concentra-se nas experiências relacionadas a psi, que incluem duas categorias. A primeira abrange relatos de percepção extra-sensorial (ESP), ou seja, indicativos da capacidade de se obter informação sem a utilização dos canais sensoriais ou de inferências lógicas. A segunda é chamada de Psicocinesia (PK) e refere-se a relatos da ação ou efeito da mente sobre a matéria, ou seja, quando as preferências ou pensamentos de pessoas parecem afetar o ambiente físico, sem a mediação do sistema muscular ou outra força física ou mecanismo físico reconhecido. Investiga se: a) é possível treinar pessoas para estarem mais aptas para perceber e utilizar os fenômenos psi no contexto experimental e b) se a manipulação de certos fatores pode aumentar significativamente os índices de psi em laboratório. Para tanto, revisa e discute por meio de sistematização a eficácia das pesquisas de treinamentos psi (TP) e os resultados de estudos que manipulam variáveis consideradas psicondutivas (VCP). Agrupa os estudos nestas duas categorias (TP e VCP), considerando variáveis específicas e comuns para os dois grupos. Avalia os estudos em blocos, segundo as variáveis consideradas, com ênfase nos dados estatísticos e do método. A revisão da literatura ocorre de março de 2007 a fevereiro de 2008 e abrange livros e artigos científicos relacionados ao tema. 128 estudos são revisados, sendo 87 deles relacionados a manipulação de VCP e 41 relacionados ao TP, totalizando 9.153 participantes em 845.815 ensaios. Avalia que 37% dos estudos TP são criticados, sendo a maior parte das críticas endereçada a problemas de método, enquanto que 16% dos estudos VCP recebem críticas. Conclui que os estudos não são eficazes em treinar psi ou manipular variáveis psi-condutivas, ainda que a maior parte deles obtenha resultados significativos e na direção esperada. De uma forma geral eles falham em termos da elaboração de métodos capazes de excluir hipóteses alternativas àquelas testadas, sendo que as principais falhas são: 1. falta de grupos controle; 2. controle inadequado da variável crença, tanto em relação aos sujeitos como aos pesquisadores; 3. falha em avaliar o real aprendizado; a maioria dos estudos são de curta ou curtíssima duração e sem a avaliação e/ou correlação dos fatores, aos quais se atribui aprendizado, com os escores psi. Com exceção de um estudo, os demais não apresentam testes posteriores para verificar a possível manutenção dos níveis de psi alcançados; 4. o efeito experimentador psi e psicológico é amplamente ignorado pela maioria dos estudos; 5. falta de parâmetros padrões para avaliar determinadas características ou estados (ex. hipnose, meditação, ganzfeld); 6. falta de uma abordagem sistêmica e integrada em relação aos fenômenos psi, aos métodos para testá-los e as múltiplas variáveis passíveis de influenciá-lo. Considera estas falhas apresentando sugestões para superá-las e uma proposta inicial exploratória de treinamento psi / This dissertation is about studies of anomalous experiences (AEs), which can be defined as uncommon and irregular, but reported by a large segment of the population. Among the variety of AEs, this work concentrates on psi-related experiences, which includes two categories. The first are reports of extrasensory perception (ESP), which suggest the capacity of obtaining information without the use of the sensory channels or logical inference. The second is called of psychokinesis (PK), which refers to reports of the action or effect of the mind on matter, or when people\'s thoughts seem to affect the physical environment, without the mediation of the muscular system, a physical force, or a recognized physical mechanism. The study explores if: a) it is possible to train people to be more capable to perceive and use psi phenomena in the experimental context and, b) if the manipulation of some factors can increase psi scores significantly in the laboratory. A review of the research on the effectiveness of psi trainings (PT) and of studies that manipulate psi-conductive variables (PCV) is presented. The studies are grouped in these two categories (PT and PCV), considering specific and common variables for both groups. Studies are evaluated in subgroups, according to specific variables, with emphasis on statistics and methods. The literature review was conducted from March 2007 to February 2008, and it includes books and scientific papers on the topic. 128 studies are reviewed; 87 of them about the manipulation of VCP and 41 of TP, for a total of 9.153 participants in 845.815 trials. 37% of the TP studies are criticized, mostly on methodological grounds, while the same was the case for 16% of the VCP studies. Although most of the studies obtained significant results in the expected direction, it is concluded that they are not effective to train psi or to manipulate psiconductive variables. In general they fail in terms of the elaboration of methods capable to exclude alternative hypotheses, and the main flaws are: 1. lack of control groups; 2. inappropriate control of the variable of belief, for both the subjects and researchers; 3. lack of evaluation of learning; most of the studies were of brief duration and without the evaluation and/or correlation of the factors to which learning is attributed, and in relation to psi scores. With the exception of one study, the rest do not present subsequent analyses to verify the possible maintenance of the psi levels obtained; 4. the experimenter effect (psi and psychological) is ignored completely in most of the studies; 5. lack of standard parameters to evaluate certain characteristics or states (for example hypnosis, meditation, ganzfeld); 6. lack of a systemic and integrated approach in relation to psi phenomena, to the methods used to test them, and to multiple variables that may influence them. In addition to discussing these problems, suggestions are presented to improve the situation, together with an exploratory initial proposal for psi training

Submitted by Viviane Lima da Cunha (viviane@biblioteca.ufpb.br) on 2016-07-26T15:35:01Z No. of bitstreams: 1 arquivototal.pdf: 1826886 bytes, checksum: 258afa1d986c7ceb99150d6dfab14db8 (MD5) / Made available in DSpace on 2016-07-26T15:35:01Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 1826886 bytes, checksum: 258afa1d986c7ceb99150d6dfab14db8 (MD5) Previous issue date: 2015-05-28 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The metaphysical discussion over causality and identity of events, in the aim of the physicalism, emerges in the context of the collapse of behaviorism. Whilst the paradigms of logical positivism dominated philosophy, the behaviorism dominated psychology. The rupture with the positivism was marked by the work of Willard V. O. Quine. The critics from the two dogmas of empiricism and the proposal of a radical translation allowed emergence of the theses of indetermination of meaning and inscrutability of reference. As alternative to empiricism, Quine recurs to ontological simplification and holism about theory, but considering the primacy of experience, he proposes a shift towards pragmatism. However, Quine’s pragmatism was founded in a behavioristic perspective on the acquisition of linguistic competences, and behaviorism didn’t stood as paradigm for the explanation of mentalist vocabulary. Quine had a great influence in the work and life of Donald Davidson. The ontological economy and the holism of theory marked Davidson’s work in his choice of events as basic entities and his approach to meaning in Truth and Meaning through a theory of truth. While in articles as Action, Reason and Causes Davidson develops an approach to the causal role of events in intention and action, stating that reasons are causes, in The Logical Form of Action Sentences and Causal Relations, he searches for the adequate logical forms of describing events and singular causal statements in order to establish an identity of events. The following metaphysical positions support, in Individuation of Events, a causal individuation criterion for events, and in Events as Particulars and Eternal vs Ephemeral Events, Davidson defends that events are spatiotemporal and unrepeatable particulars, finalizing a metaphysical discussion over of events that will enable him to approach the problem of the mind-body relation, in the anomalous monism argument. Donald Davidson’s anomalous monism presented in Mental Events proposes the thesis of monism – identity between physical events and mental events –, and anomalism of the mental – events do not fall under strict causal laws. To support these theses Davidson formulates three principles, whose conjunction gives us a non-reductionist version of token physicalism and, therefore, permits us to conciliate the mentalist vocabulary with the structure of physicalist language. In this sense, anomalous monism supports a supervenience theory of the mental. Despite the critics made to anomalous monism, as the epiphenomenalism accusation, the theory only crumbles in its initial presuppositions that is that of a priori causality and identity. Thus, the frailest aspects of the argument consist in the difficulty of tracking and identify in experience neural events with mental events, and in the formulation of strict laws. Those questions depend, respectively, on the advancement of neurosciences and physics. The present work, by the name of “Identity, Differentiation and Metaphysics of Events”, consists on an approach to metaphysics of events, in the context of the physicalism of tokens, more specifically to the Donald Davidson’s argument of the anomalous monism that argues for the identity of physical events and mental events and the causal role of mental events. It pretends, therefore, to coordinate the metaphysical discussion of events with Davidson’s anomalous monism. / A discussão metafísica sobre a causalidade e a identidade de eventos, no âmbito do fisicalismo, surge no contexto do colapso do behaviorismo. Porquanto os paradigmas do positivismo-lógico dominaram a filosofia, o behaviorismo dominou a psicologia. A ruptura com o positivismo é marcada pela obra de Willard V. O. Quine: a crítica aos dois dogmas do empirismo e a proposta de uma tradução radical, permitiu erguer as teses da indetermi-nação do significado e inescrutabilidade da referência. Como alternativa ao empirismo, Quine recorre à simplificação ontológica e ao holismo da teoria, mas com a primazia da experiência, propondo assim uma guinada rumo ao pragmatismo. Contudo, o pragmatismo de Quine era fundamentado numa perspectiva behaviorista para a aquisição de competên-cias linguísticas, e o behaviorismo não se firmou como paradigma para a explicação da vocabulário mentalista. Quine teve grande influência no trabalho e vida de Donald Davidson. A economia ontológica e o holismo da teoria marcam a obra de Davidson através da escolha de eventos como entidades básicas e da proposta de problematização do significado, em Verdade e Significado, através de uma teoria da verdade. Enquanto que em artigos como Action, Reasons and Causes Davidson desenvolve uma abordagem ao papel causal de eventos na intenção e na ação, afirmando que razões são causas, em The Logical Form of Action Sentences e Causal Relations, ele explora as formas lógicas adequadas para descrever eventos e para declarações causais singulares e para estabelecer uma identidade de eventos. As posições metafísicas daqui decorrentes sustentam, em Individuation of Events, um critério de individuação causal de eventos e em Events as Particulars e Eternal vs Ephemeral Events, Davidson sustenta que eventos são particulares espaciotemporais irrepetíveis, finalizando uma discussão metafísica de eventos que lhe permitirá abordar o problema da relação corpo-mente, no argumento do monismo anômalo. O monismo anômalo de Davidson, apresentado em Mental Events propõe as teses do monismo – identidade entre eventos físicos e eventos mentais –, e do anomalismo do mental – eventos mentais falham em cair sob leis causais estritas. Para suportar essas teses, Davidson formula três princípios cuja conjunção nos dá uma versão não reducionista do fisicalismo de ocorrências, que, portanto, permite conciliar o vocabulário mentalista com a estrutura linguística fisicalista. Assim, o monismo anômalo suporta uma teoria da superveniência do mental. Apesar do monismo anômalo sofrer algumas críticas, como a acusação de epifenomenalismo, a teoria só sucumbe nos seus pressupostos iniciais, ou seja, a causalidade e a identidade a priori. Os aspetos mais frágeis do argumento consistem na dificuldade de rastrear e identificar, na experiência, eventos neurais com eventos mentais, e na formulação de leis estritas. Questões estas que dependem, respetivamente, do avanço das neurociências e desenvolvimento da física. O presente trabalho, pelo nome de “Identidade, Diferenciação e Metafísica de Eventos”, consiste numa abordagem à metafísica de eventos, no contexto do fisicalismo de ocorrências, mais especificamente do argumento do monismo anômalo de Davidson, que afirma a identidade entre eventos físicos e eventos mentais, assim como o papel causal de eventos mentais. Pretende, portanto, coordenar a discussão metafísica de eventos com o monismo anômalo de Davidson.

Made available in DSpace on 2015-03-26T13:35:13Z (GMT). No. of bitstreams: 1 texto completo.pdf: 1486986 bytes, checksum: a086a712989295bff60986e7d0bcdd7e (MD5) Previous issue date: 2010-02-25 / Fundação de Amparo a Pesquisa do Estado de Minas Gerais / Cadmium telluride films grown on glass substrates covered by fluorine doped tin oxide (TCO) were studied by generic dynamical scaling theory proposed by L ópez et al. [Phys. Rev. Lett. 84, 2199 (2000)]. The samples were grown by Ferreira et al. [Appl. Phys. Lett. 88, 244102 (2006)] using hot wall epitaxy and the interface scaling properties were investigated in this work using the power spectrum, height-height correlation function, and interface width. The theory adopted has six scaling exponents, but only four of them are independent. However, in order to classify which growth regime the system follows one should analyze three of these exponents, namely, &#945;, &#945;loc and &#945;s which are related to the global, local, and power spectrum fluctuations, respectively. The results show that the studied system exhibit anomalous scaling behavior characterized by global roughness exponent di fferent from the local one. Actually, in agreement with the adopted theory we have found a growth regime ruled by faceted interfaces, characterized by &#945;loc = 1 and &#945; &#8800; &#945;s > 1. This prediction of the anomalous scaling theory was corroborated by atomic force microscopy of the samples. We conjecture that non-local effects, caused by the initial disorder imposed by the amorphous substrate, rule the anomalous scaling. / Filmes de telureto de cádmio crescidos sobre substratos de vidro recobertos com oxido de estanho dopado com flúor (TCO) foram estudados usando a teoria de escala dinâmica proposta por Lopez et al. [Phys. Rev. Lett. 84, 2199 (2000)]. As amostras foram crescidas por Ferreira et al. [Appl. Phys. Lett. 88, 244102 (2006)] usando a técnica de epitaxia por paredes quentes e as propriedades de escala da interface foram investigadas neste trabalho através do espectro de potência, da função de correlação de alturas e da espessura da interface. A teoria usada possui seis expoentes de escala, sendo quatro independentes. Entretanto, para classificar qual regime de crescimento o sistema obedece deve-se analisar três desses expoentes, a saber, &#945;, &#945;loc e &#945;s relacionados com as flutuações globais, locais e do espectro de potência da interface, respectivamente. Os resultados mostram que o sistema estudado apresenta comportamento de escala anômalo caracterizado pelo expoente de rugosidade global diferente da rugosidade local. Mais precisamente, em acordo com a teoria usada, encontramos um regime de crescimento com interfaces facetadas caracterizadas por &#945; loc = 1 e &#945; &#8800; &#945; s > 1. Essa previsão da teoria de escala anômala foi corroborada através de microscopia de força atômica das amostras. Conjecturamos que efeitos não-locais originados pela desordem inicial imposta pelo substrato amorfo são os fatores que originam o comportamento de escala anômalo.

Nesta tese foi estudado o transporte de partículas na borda do plasma confinado magneticamente em tokamaks a partir de um modelo para ondas de deriva proveniente de flutuaçõoes eletrostáticas geradas pela não uniformidade do plasma. Para investigar esse problema, consideramos o modelo com duas ondas de deriva, que possui uma complexa dinâmica não linear onde podemos encontrar tanto transporte anômalo quanto transporte difusivo. Para a encontras no plano de fases as Estruturas Lagrangianas Coerentes (ELCs) e os jatos, foram confeccionados mapas de Poincaré, diagramas de expoente de Lyapunov a tempo finito, diagramas de deslocamento quadrático, diagramas de autocorrelação da velocidade e o diagrama de retorno. Para avaliar o impacto dessas ELCs no transporte de partículas foram analisados a série temporal do desvio padrão médio, da dispersão relativa e dos saltos dentro do mapa de Poincar´e e também foram confeccionados histogramas com a distribuição desses saltos. Foi encontrado que, com duas ondas de deriva e para uma determinada combinação de parâmetros, surgem correntes de jato, que persistem por longos períodos, imersas na região caótica. Verificamos que, assim como nas ilhas, a região interna às correntes de jato são inacessíveis às ELCs. Também foi encontrado que, quando existe uma corrente de jato, o transporte observado na região caótica não é simétrico com uma pequena deriva na direção contraria ao jato. Esse fenômeno observado ocorre em contrapartida ao caso típico de sistemas com mistura em que as ELCs tem acesso a todo o plano de fase e o transporte é difusivo. / In this thesis we studied the particle transport in the edge of magnetically confined plasma in tokamaks using a model of drift waves due to electrostatic fluctuations generated by the non-uniformity of the plasma. To investigate this issue, we consider the model with two drift waves, which has a complex nonlinear dynamics where we can find both anomalous and diffusive transport. To find the Lagrangian Coherent Structures (LCSs) and the jets, we used Poincaré maps, Finite time Lyapunov exponent diagrams, quadratic displacement diagrams, autocorrelation velocity diagrams and return displacement diagram. To evaluate the impact of LCSs in the transport of particles, we analyzed the time series of both average standard deviation and relative dispertion and also histograms of the distribution of these jumps. It was found that, with two drift waves and for a given combination of parameters, a jet streams appear in the phase space and persist for long periods of time immersed in the chaotic region. We found that, as well as on the islands, the inner region of the jet streams are inaccessible to LCSs. It was also found that when there is a jet stream, the transport observed in the chaotic region is not symmetrical and have a small drift in the opposite direction to the jet. This phenomenon is observed in contrast to the typical case of systems with mixing in wich the LCSs have access to all the phase space and the trasnport is diffusive.