No / A novel dispersive system operating at 1064-nm excitation and coupled with transfer electron InGaAs photocathode and electron bombardment CCD technology has been evaluated for the analysis of drugs of abuse and explosives. By employing near-IR excitation at 1064-nm excitation wavelength has resulted in a significant damping of the fluorescence emission compared to 785-nm wavelength excitation. Spectra of street samples of drugs of abuse and plastic explosives, which usually fluoresce with 785-nm excitation, are readily obtained in situ within seconds through plastic packaging and glass containers using highly innovative detector architecture based upon a transfer electron (TE) photocathode and electron bombarded gain (EB) technology that allowed the detection of NIR radiation at 1064nm without fluorescence interference. This dispersive near-IR Raman system has the potential to be an integral part in the armoury of the forensic analyst as a non-destructive tool for the in-situ analysis of drugs of abuse and explosives. Copyright (c) 2015 John Wiley & Sons, Ltd.

The incompressible Navier-Stokes equations have proven formidable for nearly a century. The present difficulties are mathematical and computational in nature; the computational requirements, in particular, are exponentially exacerbated in the presence of high Reynolds number. The issues are further compounded with the introduction of markers or an immiscible fluid intended to be tracked in an ambient high Reynolds number flow; despite the overwhelming pragmatism of problems in this regime, and increasing computational efficacy, even modest problems remain outside the realm of direct approaches. Herein three approaches are presented which embody direct application to problems of this nature. An LES model based on an entropy-viscosity serves to abet the computational resolution requirements imposed by high Reynolds numbers and a one-stage compressive flux, also utilizing an entropy-viscosity, aids in accurate, efficient, conservative transport, free of low order dispersive error, of an immiscible fluid or tracer. Finally, an integral commutator and the theory of anti-dispersive spaces is introduced as a novel theoretical tool for consistency error analysis; in addition the material engenders the construction of error-correction techniques for mass lumping schemes.

Approved for public release, distribution is unlimited / The effect of friction-stir processing (FSP) on the microstructure of a cast nickel-aluminum bronze (NAB) material has been characterized by various micro-analytical methods including orientation imaging microscopy (OIM). Cast NAB is widely utilized in the production of propellers for the surface ships and submarines of the U.S. Navy due to excellent corrosion-resistance. New applications require improved mechanical properties that may be attainable using FSP to achieve localized microstructure modification. Friction between a rotating tool and the surface of the material results in a *stirring* action that, in turn, produces adiabatic heating and local softening of the material. The tool rotation results in very large shear deformations in the softened regions and thus microstructure refinement and homogenization; in effect FSP may convert an as-cast microstructure to a wrought condition in the absence of macroscopic shape change. In as-cast material, results of optical and scanning electron microscopy (using energy dispersive analysis) show an ` (FCC) matrix containing globular and particulate dispersions that correspond to the *I, *II and *IV second phases; these represent various morphologies of the Fe3Al intermetallic compound, which has a D03 structure. Also present are lamellar particles of *III, which is NiAl and has a B2 structure. The grain size in the ` matrix is ~ 1 mm. In OIM, the microtexture and microstructure in the ` (FCC) matrix may be readily obtained and analyzed. However, interatom distances in the Fe3Al and NiAl phases differ by only about one percent and so these phases are not distinguishable from one another during OIM. Altogether, microstructure and microtexture analysis showed that there are several regions in the thermomechanically affected zone (TMAZ) of a material subjected to FSP. From base material inward toward the TMAZ, these include: annealing effects in undeformed base material; a region just inside the TMAZ in which grain deformation and C-type shear deformation textures are observed; regions of highly refined and recrystallized grains further inside the TMAZ, wherein the grain size is < 5æm; and, finally, regions of elongated, banded and twinned grain structures that suggest grain growth following recrystalliztion. / Lieutenant, United States Navy

Dans cette thèse nous nous intéressons aux propriétés qualitatives et quantitatives des solutions de quelques équations d'ondes en milieux dispersifs ou dispersifs-dissipatifs. Dans une première partie, nous étudions le problème de Cauchy associé aux équations de Benjamin-Ono généralisées. A l'aide de transformées de jauge, combinées avec des outils d'analyse harmonique, nous prouvons des résultats concernant le caractère localement bien posé pour des données initiales de régularité minimale dans l'échelle des espaces de Sobolev. Dans une seconde partie, nous étudions le problème de Cauchy pour des versions dissipatives des équations de Benjamin-Ono et de Korteweg-de Vries. Nous mettons en évidence l'influence des effets dissipatifs sur ces équations en donnant des résultats optimaux sur leur caractère bien ou mal posé. Ceux-ci sont obtenus en travaillant dans des espaces de type Bourgain adaptés à la partie dispersive-dissipative. Pour finir nous étudions le comportement asymptotique des solutions des équations de KdV dissipatives, lorsque celles-ci existent pour tout temps, en calculant explicitement les premiers termes du développement asymptotique dans de nombreux espaces de Sobolev / This thesis deals with the qualitative and quantitative properties of solutions to some wave equations in dispersive or dispersive-dissipative media. In the first part, we study the Cauchy problem for the generalized Benjamin-Ono equations. By means of gauge transforms combined with some harmonic analysis tools, we prove some local well-posedness results for initial data with minimal regularity in Sobolev spaces. In the second part, we study the Cauchy problem for some dissipative versions of the Benjamin-Ono and Korteweg-de Vries equations. We show the influence of the dissipative effects and prove sharp well and ill-posedness results. This is obtained by working in suitable Bourgain's spaces, adapted to the dispersive-dissipative part of the equation. Finally, we study the asymptotic behavior of solutions to the dissipative KdV equations. We explicitly compute the first terms of the asymptotic expansion in Sobolev spaces

O câncer de mama é o tipo de câncer mais frequente entre as mulheres, sendo a mamografia a técnica mais utilizada para sua detecção. No entanto, essa técnica possui algumas limitações, como o baixo contraste, o qual pode ser associado, dentre outros fatores, a radiação espalhada. Apesar desse fato, novas técnicas baseadas na detecção do espalhamento vêm sendo empregadas em um vasto campo de aplicação, como na caracterização de materiais e tecidos biológicos. Há na literatura diversos estudos sobre perfil de espalhamento para a caracterização de tecidos mamários, porém ainda são poucos os estudos sobre imagem por espalhamento de mama e de otimização de contraste. Além disso, essas imagens são realizadas apenas em pequenas amostras de mama. Uma das possibilidades para o estudo de mamas de dimensões reais é a aplicação do método Monte Carlo (MC). Neste trabalho, foi estudado e otimizado um sistema de difração de raios X dispersivo em energia (SDRXDE) para medidas de perfis de espalhamento e um sistema para formação de imagens por espalhamento utilizando estas informações. O SDRXDE foi caracterizado experimentalmente, analiticamente e por simulação Monte Carlo, enquanto que o segundo sistema foi caracterizado analiticamente e por simulação Monte Carlo. Os resultados obtidos mostraram que as principais correções para o SDRXDE foram auto-atenuação, o espectro incidente, eficiência de detecção e múltiplo espalhamento. Outro fator importante que afeta o perfil de espalhamento resultante é a resolução de momento do sistema, o qual depende dos parâmetros geométricos (abertura dos colimadores, distâncias, ângulo de espalhamento e espessura da amostra) e da resolução de energia do detector. Os resultados para o sistema de imagem mostram claramente a capacidade dessas imagens na detecção de um nódulo no interior da mama. A respeito da otimização das condições de irradiação da mama e detecção da radiação espalhada, os resultados alcançados demostram a viabilidade experimental da geração destas imagens num ambiente clínico. / Breast cancer is the most frequent type of cancer among women, being mammography the technique more used for its detection. However, this technique presents some limitations, such as low contrast, which may be associated with scattered radiation. Thus, new scatterinng detection techniques have been employed in different fields such as characterization of biological materials and tissues, such as characterization of scattering profile for breast tissue, although there are still few studies on breast image and contrast optimization. Moreover, the images are originated from small breast samples. In this context, one of the possibilities for the study of actual breast dimensions is the application of the Monte Carlo method. Thus, this work studied optimized an energy X ray diffraction system (EDXRD) for measures of scattering profile and developed a system for imaging using this information. The EDXRD system was studied and optimized by experimentally, analytically and Monte Carlo simulation, while the image system was studied analytically and simulated by Monte Carlo. The results showed that the main corrections for the EDXRD system are self-attenuation, incident spectrum, detection eficiency and multiple scattering. Another important factor that affects scattering profile is the system momentum resolution, which depends on geometric parameters (collimator aperture, distances, scattering angle and sample thickness) and detector energy resolution. The results for the imaging system showed that a nodule could be detected within the breast. Finaly the optimizations of breast radiation conditions and radiation detection showed the viability of generating experimental scattering images in clinical environment.

A liga Ti-6Al-4V tem sido usada com sucesso como biomaterial com aplicações nos campos da odontologia e ortopedia. As características da liga Ti-6Al-4V que a tornaram um material interessante são sua boa resistência à corrosão em meio biológico, combinada com um excelente grau de biocompatibilidade. Os efeitos biológicos a longo prazo dos íons metálicos resultantes da lenta lixiviação dos implantes de titânio não estão completamente entendidos. É conhecido que os íons titânio são considerados agentes químicos cancerígenos, os íons alumínio causam desordem neurológicas e os íons vanádio estão associados com distúrbios enzimáticos, entre outros problemas. O recobrimento das ligas de titânio por óxido de titânio (TiO2) pode atuar como uma barreira química para os íons lixiviados da superfície metálica da liga, além deste óxido ser um bom osseoindutor. O processo de aspersão térmica é amplamente empregado na aplicação de recobrimentos por óxidos. Uma vez que este processo acontece em altas temperaturas, onde partículas fundidas ou semi-fundidas aderem ao substrato, pode ocorrer difusão localizada. O objetivo deste estudo é caracterizar a interdifusão dos elementos de liga através das camadas superficiais do sistema Ti-6Al-4V/TiO2. Os recobrimentos de TiO2 foram preparados pela técnica de aspersão por plasma. A zona recoberta mostrou pequena porosidade distribuída por toda a camada e algumas trincas radiais. Adicionalmente, uma grande quantidade de buracos foi observada na região entre-camadas. Neste trabalho, a interface Ti-6Al-4V/TiO2 foi estudada por microscopia eletrônica de varredura. Os perfis de difusão do Ti, Al, V e O nas camadas superficiais da amostra recoberta foram obtidos por microanálise semi-quantitativa por energia dispersiva de raios-X. A caracterização química superficial do lado substrato depois da deposição de TiO2 mostrou a formação localizada de TiO. Na região entre-camadas foram observados os perfis de difusão característicos com forma de S para o Ti, V e O. O perfil de difusão do Al mostrou um pico na região entre-camadas indicando um acúmulo de Al2O3 nos buracos presentes nesta zona. O TiO2 foi identificado como o maior constituinte no lado revestimento. Pequenas quantidades de Al e V foram também detectadas homogeneamente distribuídas dentro do depósito. A presença do Al e V (metais tóxicos) na superfície externa do depósito indica que estes metais não competem com a oxidação da camada depositada indicando um efeito desmascarante da superfície da liga metálica pelo óxido superficial TiO2. / Ti-6Al-4V alloy has been used with some success as biomaterial with applications in the field of dentistry and orthopaedics. The features with make the Ti-6Al-4V alloy such an interesting material are its good corrosion resistance in the biological environment, combined with an excellent degree of biocompatibility. The long-term biological effects of the slowly leaching of metal ions from titanium implants are not completely understood. It is known that the titanium ions are considered chemical carcinogen, aluminium ions cause neurological disorders and, vanadium ions are associated with irreversible enzymatic disturbance, among other problems. Titanium oxide (TiO2) coatings on titanium alloys can act as a chemical barrier for ions leaching from the metallic alloy surface, beside the fact that this oxide is a very good osteoinductor. The thermal spray process is widely used to apply oxide coatings. Once this is a high temperature process where molten or semi-molten particles impinge upon the substrate, localized diffusion can occur. The aim of this study is characterize the inter-diffusion of the alloying elements through the surface layers of the system Ti-6Al-4V/TiO2. The TiO2 coatings were prepared by the plasma spray technique. The coated zone showed some porous distributed in all layer and a few radial cracks. Additionally, large amount of holes were observed in the interlayer region. In this work, the interface Ti-6Al-4V/TiO2 was studied by scanning electron microscopy. Diffusion profiles of Ti, Al, V and O in the surface layers of coated samples were measured by semi-quantitative energy dispersive X-ray microanalysis. Chemical surface characterization of the substrate side after the TiO2 deposition showed the localized formation of TiO. At the interlayer region was observed the characteristic S shape diffusion profiles for Ti, V and O. The Al diffusion profile showed a peak in the interlayer region indicating anaccumulation of Al2O3 into the holes present in this zone. TiO2 was identified as the major component in the coating side. Small amounts of Al and V were also detected homogeneously distributed inside the deposit. Presence of Al and V (toxic metals) on the external surface of the deposit indicated that these metals did not compete with the oxidation of the deposited layer indicating a non-masking effect of metallic alloy surface by the TiO2- surface oxide.

Ces travaux de thèse concernent la mise au point d’une méthodologie de conception de filtres passe-bandes à couplages dispersifs permettant d’optimiser la sélectivité de ces filtres en générant et en contrôlant la position de zéros de transmission supplémentaires. Un état de l’art sur les différentes approches proposées dans la littérature pour la synthèse de filtres hyperfréquences à couplage dispersif est d’abord proposé. Cette analyse est illustrée par plusieurs exemples concrets, et une structure en particulier, comportant un couplage par plot capacitif, constitue le point de départ des travaux. De nouveaux éléments de couplage dispersifs ont été ensuite proposés, capables de générer aussi bien des couplages positifs que négatifs, permettant ainsi de positionner les zéros de transmission dans la bande stoppée supérieure ou inférieure. Ces éléments ont alors été intégrés dans des structures de filtrage plus complexes pour réaliser par exemple des structures en ligne possédant plusieurs zéros de transmission hors bande ou des filtres multibandes à la sélectivité renforcée. Plusieurs des dispositifs conçus ont été fabriqués et mesurés. Les résultats expérimentaux sont en bon accord avec les simulations validant ainsi l’approche proposée. / This thesis report deals with the development of a methodology for the design of bandpass filters including dispersive coupling to optimize the selectivity of these filters by generating and controlling the position of additional transmission zeros. A state of the art on the different approaches proposed in the literature for the synthesis of microwave filters with dispersive coupling is first proposed. This analysis is illustrated by several concrete examples, and a structure in particular, comprising a coupling capacitive post, is the starting point of the work. New dispersive coupling elements were then proposed, capable of generating both positive and negative couplings, thus enabling the transmission zeros to be positioned in the upper or lower stopped band. These elements have then been integrated in more complex filtering structures to achieve, for example, on-line structures having several out-of-band transmission zeros or multiband filters with enhanced selectivity. Many of the devices designed have been manufactured and measured. The experimental results are in good agreement with the simulations validating the proposed approach.

Dans cette thèse, on s'intéresse à l'étude qualitative des solutions d'équations aux dérivées partielles hamiltoniennes par le biais de la théorie des mesures invariantes. L'existence d'une telle mesure pour une EDP fournit, en effet, des informations sur sa dynamique en temps long. Nous étudierons deux situations quelque peu "extrémales". Dans une première partie, nous nous intéressons aux équations ayant une infinité de lois de conservation et dans une seconde, aux équations dont on ne connaît qu'une seule loi de conservation non triviale.Nous étudions les premières équations par le biais de l'équation de Benjamin-Ono. Il s'agit d'un modèle de description des ondes internes dans un fluide de grande profondeur.Nous nous intéressons à la dynamique de cette équation sur l'espace C^infty(T) en lui construisant une mesure invariante sur cet espace. Par conséquent, une propriété de récurrence presque sûre (par rapport à cette mesure) est établie pour les solutions infiniment lisses de cette équation. Nous prouvons, ensuite, des propriétés de non-dégénérescence pour cette mesure. En effet, nous montrons que, via cette mesure, une infinité de fonctionnelles indépendantes ont des distributions absolument continues par rapport à la mesure de Lebesgue sur R. Enfin, nous montrons que cette mesure est de nature au moins $2$-dimensionnelle. Dans ce travail, nous avons utilisé l'approche Fluctuation-Dissipation-Limite (FDL) introduite par Kuksin-Shirikyan. Notons qu'une propriété de récurrence presque sûre a été établie pour les solutions de régularité Sobolev de l'équation de Benjamin-Ono, dans les travaux de Deng, Tzvetkov et Visciglia.Dans l'autre partie de la thèse, nous abordons l'équation de Klein-Gordon à non-linéarité cubique, c'est un exemple d'EDPs hamiltoniennes pour lesquelles il n'est connu qu'une seule loi de conservation non triviale. Cette équation modélise l'évolution d'une particule massive relativiste. Ici, nous considérons les cas où l'équation est posée sur le tore tri-dimensionnel ou sur un domaine borné de R^3 à bord assez régulier. Nous lui construisons une mesure invariante concentrée sur l'espace de Sobolev H^2, en utilisant toujours l'approche FDL. Un autre aspect de ce travail est d'étendre le cadre de cette approche au contexte des EDPs à une seule loi de conservation, en effet, dans les travaux antérieurs, l'approche FDL avait nécessité deux lois de conservation pour fonctionner. Puis nous établissons une propriété de non-dégénérescence pour la mesure construite. Par conséquent, une propriété de récurrence presque sûre, par rapport à la mesure construite, est prouvée. Notons que des travaux antérieurs dus à Burq-Tzvetkov, de Suzzoni, Bourgain-Bulut et Xu ont traité la question de mesure de Gibbs invariante pour des équations des ondes dans un contexte radial. / In this thesis, we are concerned with the qualitative study of solutions of Hamiltonian partial differential equations by the way of the invariant measures theory. Indeed, existence of such a measure provides some informations concerning the large time dynamics of the PDE in question. In this thesis we treat two "extremal" situations. In the first part, we consider equations with infinitely many conservation laws, and in the second, we study equations for which we know only one non-trivial conservation law.We study the first equations by considering the Benjamin-Ono equation. The latter is a model describing internal waves in a fluide of great depth.We are concerned with the dynamics of that equation on the space C^infty(T) by constructing for it an invariant measure on that space. Accordingly, an almost sure (w.r.t. this measure) recurrence property is established for infinitely smooth solutions of that equation. Then, we prove qualitative properties for the constructed measure by showing that there are infinitely many independent observables whose distributions via this measure are absolutely continuous w.r.t. the Lebesgue measure on R. Moreover, we establish that the measure is of at least 2-dimensional nature. In this work, we used the Fluctuation-Dissipation-Limit (FDL) approach introduced by Kuksin and Shirikyan. Notice that an almost sure recurrence property for the Benjamin-Ono equation was established on Sobolev spaces by Deng, Tzvetkov and Visciglia.In the second part of the thesis, we consider the cubic Klein-Gordon equation, which is an example of Hamiltonian PDEs for which we know only one conservation law. This equation models the evolution of a massive relativistic particle. Here, we consider both the case of the tri-dimensional periodic solutions and those defined on a bounded domain of R^3. In both settings, we construct an invariant measure concentrated on the Sobolev space H^2xH^1, again with use of the FDL approach. Another aspect of this work is to extend the FDL approach to the context of PDEs having only one conservation law; indeed, in previous works, this approach required two conservation laws. Qualitative properties for the measure and almost sure (w.r.t. this measure) recurrence for H^2-solutions are proven. Notice that previous works by Burq-Tzvetkov, de Suzzoni, Bourgain-Bulut and Xu have treated the invariant Gibbs measure problem in the radial symmetry context for waves equations.

O espalhamento de ondas eletromagnéticas por partículas isoladas, com propriedades ópticas e formatos arbitrários, encontra aplicações nas mais diversas áreas do conhecimento. Usualmente, o espalhamento eletromagnético é investigado via grandezas auferidas na região de campo distante. Para partículas inomogêneas, no entanto, as ressonâncias nas seções de choque de espalhamento podem não corresponder a um aumento de intensidade do campo eletromagnético nas vizinhanças imediatas da partícula (região de campo próximo). Esse efeito pode ser induzido em nanopartículas dielétricas com revestimentos plasmônicos e foi recentemente explicado em termos da ressonância de Fano. Essa ressonância resulta da interferência entre um modo eletromagnético não ressonante (processo de fundo) e um modo discreto ressonante (ressonância de plásmon), produzindo um formato assimétrico de linha espectral. Para o entendimento de como os modos de superfície no campo próximo acoplam-se às ressonâncias nas seções de choque, é necessário o cálculo de funcionais dos campos eletromagnéticos internos às partículas ou em suas vizinhanças imediatas. Neste estudo, calculamos a energia eletromagnética no interior de centros espalhadores nas geometrias esférica e cilíndrica. Fazemos aqui o vínculo dos campos internos às grandezas de espalhamento no campo distante via seção de choque de absorção e conservação de energia. Aplicamos nossos resultados a metamateriais dispersivos, estudando as propriedades do espalhamento por esferas revestidas e por esferas quirais, no regime de refração negativa, e por cilindros revestidos sob incidência oblíqua de radiação. Mediante a energia interna às partículas, demonstramos novos efeitos de aumento de intensidade de campo interno fora da ressonância de espalhamento e fornecemos resultados analíticos para a análise dessas ressonâncias, tanto em espalhamento simples quanto múltiplo. / Electromagnetic wave scattering by single particles with both shapes and optical properties arbitrary finds applications in several areas of knowledge. Usually, the electromagnetic scattering is investigated via measured quantities in the far-field region. However, for inhomogeneous particles, resonances in scattering cross sections may not correspond to the electromagnetic field enhancement in the vicinity of a particle (near-field). This effect can be induced in dielectric nanoparticles with plasmonic coatings, and it has recently been explained in terms of the Fano resonance. The Fano resonance results from the interference between a non-resonant electromagnetic mode (background or continuous) and a resonant discrete mode (localized plasmon resonance), leading to an asymmetric lineshape. To understand how the surface modes in the near-field are connected to the cross section resonances, functionals of the electromagnetic fields within scatterers or in their vicinity are required. In this study, we calculate the electromagnetic energy inside scatterers in both cylindrical and spherical geometries. We obtain a connection between the internal energy and the scattering quantities in the far-field via absorption cross section and energy conservation. We apply our results to dispersive metamaterials, studying scattering properties of coated and chiral spheres in the negative refraction regime, and coated cylinders under oblique incidence of radiation. By the electromagnetic energy inside particles, we demonstrate new off-resonance field enhancement effects and provide analytical tools to analyze these resonances in both single and multiple scattering regimes.

The commercial polycrystalline superalloy RR1000 developed for turbine disc applications contains a large number of alloying elements. This complex alloy chemistry is required in order to produce appropriate microstructures and the required mechanical properties, such that the most important strengthener γʹ displays complex alloy chemistry. The broad aim of this project is to develop an approach to measuring the composition of γʹ precipitates at a broad range of length scales from nanometres to hundreds of nanometres, and subsequently develop a better understanding of the role of thermodynamics and diffusion kinetics on γʹ phase separation and precipitate growth. A solution of the absorption-corrected EDX spectroscopy to spherical particles was developed in our work, therefore enabling the quantitative analysis of precipitates' composition using an absorption-corrected Cliff-Lorimer approach. By performing this quantification, size-dependent precipitate compositional variations were obtained. Examination of this quantitative approach was compared to thermodynamic calculations of primary γ' precipitates possessing equilibrium compositions. Given the development of semi-quantitative compositional measurements for spherical γʹ precipitates and that cooling is one of the most common and critical regimes in physical metallurgy of Ni-based superalloys, this approach was then applied to study the local compositional variations that are induced in γ' precipitates when the alloy RR1000 undergoes different cooling rates. These measured compositions have been compared to detailed thermodynamic calculations and provide new experimental evidence of the importance of the dominant role of aluminium antisite diffusion in determining the low-temperature growth kinetics of fine-scale γ' precipitates. We have applied a similar analysis approach to study the compositional variations of γʹ cores within the class of secondary precipitates upon cyclic coarsening and reversal coarsening. It was shown that supersaturated Co in secondary γʹ exhibits an overall trend towards the equilibrium but Co content can significantly increase as γʹ coarsens. It was demonstrated that the limited elemental diffusivity in γ and γʹ compared to the observed coarsening rate in the coarsening regime results in the long-lasting Co supersaturation in γʹ and builds up elemental enhancements or depletions. These inhomogeneous elemental distributions produce compressive elastic constraints on large-scale secondary γʹ, therefore inducing morphological instability of these γʹ and causing the reversal coarsening. These results enable us to better understand the role that both thermodynamics and limited diffusion kinetics plays in controlling the complex microstructures of γ' precipitates.