Orientador: Carlos Manuel Giles Antunez de Mayolo / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Física Gleb Wataghin / Made available in DSpace on 2018-08-19T11:26:29Z (GMT). No. of bitstreams: 1 Souza_ThaisDiniz_M.pdf: 31446941 bytes, checksum: 75f1c0838febdfa063257bf308ddba57 (MD5) Previous issue date: 2011 / Resumo: Esta dissertação de mestrado teve como objetivo realizar imagens por contraste de fase de amostras in vitro de articulações e cartilagens utilizando duas técnicas: a Imagem Realçada por Difração (IRD) e o Método da Propagação. O sistema para a IRD foi montado no Laboratório Nacional de Luz Síncrotron (XRD2-LNLS), utilizando uma fonte de radiação síncrotron. O sistema para o Método da Propagação foi montado no Laboratório de Cristalografia Aplicada e Raios X (LCARX-UNICAMP), utilizando uma fonte de raios X microfoco, instalada dentro de uma cabana experimental blindada com chumbo. As amostras utilizadas foram corpos de provas e amostras de cartilagens e articulações fornecidos pelo grupo do Prof. Dr. William Dias Belangero da Faculdade de Ciências Médicas (FCM-UNICAMP). No Laboratório de Cristalografia foi realizado todo o processo de montagem e instalação da estação experimental com a fonte de raios X microfoco. Nessa estação foram realizadas imagens pelo método convencional e pelo método da propagação. No mesmo laboratório foi também realizado um estudo de caso em colaboração ao grupo da FCM, usando casos clínicos de implantes de próteses metálicas em articulações, estudou-se a regeneração do tecido ósseo após a lesão para fixação da prótese, utilizando amostras in vitro de patas lesionadas de ratos. Por último foram realizadas aquisições tomográficas no método convencional e de propagação de um joelho de rato e de um joelho de coelho. As imagens obtidas pelo método da propagação tanto dos corpos de prova quanto das amostras biológicas mostram que há uma melhor qualidade na imagem, com maior contraste nas bordas e visualização de estruturas que não são visíveis nas radiografias convencionais. O mesmo acontece com as reconstruções tomográficas, que mostram detalhes da anatomia da amostra, facilitando a visualização de danos em tecidos moles.Essa técnica é vantajosa por não precisar de nenhuma instrumentação ótica, sendo explorado somente o tamanho focal da fonte de raios X e a distância entre a amostra e o detector. No LNLS foi usada a linha XRD2 com 10,34 keV de energia para realizar imagens realçadas por difração usando o detector Pilatus. As imagens realçadas por difração obtidas no LNLS têm qualidade superior devido à utilização de um cristal analisador colocado após a amostra. Este cristal funciona como uma estreita fenda angular resultando em imagens com ganho de contraste em relação às imagens obtidas pelos métodos convencionais / Abstract: In this dissertation we have produced in vitro joint and cartilages images by two especific methods of phase contrast imaging: Diffraction enhanced imaging (DEI) method and Propagation method. The DEI setup was implemented at the XRD2 beamline of the Brazilian National Synchrotron Light Laboratory (LNLS) in Campinas. The propagation method setup was implemented at the X-ray applied Crystallography Laboratory (LCARX) using a microfocus source (5 µm), that was installed inside of an experimental hut shielded with lead. The samples used were test objects and specimens of joints and cartilages provided by the group of Dr. William Dias Belangero of School of Medical Sciences (FCM-UNICAMP). In the Crystallography Laboratory was built an experimental station to perform tomography with a microfocus source. At this station pictures were realized by the conventional method and the propagation method. At the same laboratory was realized a study in order to colaborate the FCM group, using clinical cases of metal implants in prosthetic joints, we studied the regeneration of bone tissue after the injury to fixation of the prosthesis, using in vitro samples of injured legs of rats. Finally, tomographic acquisitions of rat and rabbit knees were performed in the conventional method and propagation method. The images obtained by the propagation method of both test objects and biological samples show that there is a better image quality, with high contrast in the edges and visualization of structures that are not visible on conventional radiographs. The same happens with the tomographic reconstructions, showing details of the anatomy of the sample, facilitating the visualization of soft tissue damage. This technique has the advantage of not requiring any optical instrumentation, only exploring the focal size of the X-ray source and the distance between sample and detector. In the LNLS was used the XRD2 beamline with 10,34 keV of energy to perform diffraction enhanced images using the detector Pilatus. The diffraction enhanced images had higher quality because this system uses an analyzer crystal placed after the sample. This crystal serves as a narrow angular slit which resulted in images with gain in contrast as compared to the conventional images methods / Mestrado / Física / Mestra em Física

Orientadores: Angelo Malachias de Souza, Eduardo Granado Monteiro da Silva / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Física Gleb Wataghin / Made available in DSpace on 2018-08-19T18:22:37Z (GMT). No. of bitstreams: 1 Pauli_Murielde_M.pdf: 18020420 bytes, checksum: ea0b8509035e788d8af363ac04130ca2 (MD5) Previous issue date: 2012 / Resumo: Esta dissertação trata do estudo estrutural e termodinâmico de sistemas orgânicos auto-organizados utilizando diferentes técnicas de espalhamento de raios-x. Multicamadas autoorganizadas de dois tipos de moléculas de ácidos fosfônicos foram analisadas: para o OPA [Ácido octadecilfosfônico - CH2(CH3)17PO(OH)2] e para o OcPA [Ácido octilfosfônico - CH2(CH3)7PO(OH)2]. Utilizando a fonte do Laboratório Nacional de Luz Síncrotron (LNLS) realizamos um conjunto de experimentos para investigar a organização lamelar e planar destas moléculas em função da temperatura. Medidas de difração convencional permitiram introduzir modelos de empilhamento capazes de identificar a coexistência de diferentes configurações de ordenamento e modificações nas mesmas em função da temperatura. Uma vez estabelecidos estes modelos fizemos uso da técnica de difração de raios-x dispersiva em energia, ainda pouco utilizada no Brasil, para obter informações detalhadas sobre o volume relativo de material ordenado com cada uma das configurações encontradas, identificando aquelas que são termicamente mais estáveis. O padrão de organização das moléculas no plano foi também investigado realizando-se medidas em geometria de transmissão de raios-x. Reunindo as informações descritas acima construímos um diagrama de fase ilustrando o ordenamento lamelar e planar das moléculas em função da temperatura. Além disso, fizemos um estudo do comportamento crítico das configurações de ordenamento nas vizinhanças da transição ordemdesordem para cada tipo de molécula e acerca da organização de curto e longo alcance das moléculas nas multicamadas. Os resultados preliminares são apresentados no fim deste trabalho / Abstract: This thesis comprises structural and thermodynamic studies on self-assembled organic systems using synchrotron x-ray scattering techniques. Multilayers obtained from selforganization of phosphonic acid molecules were analyzed for two different compounds: the octadecylphosphonic acid [OPA ¿ CH2(CH3)17PO(OH)2] and the octylphosphonic acid [OcPA ¿ CH2(CH3)7PO(OH)2]. Using the source of the Brazilian Synchrotron Light Laboratory (LNLS) we have performed an ensemble of experiments to investigate their lamellar and in-plane order of these molecules and their behavior. Conventional angle-resolved X-ray diffraction measurements were analyzed using kinematical models and allowed to verify the coexistence of distinct lamellar configurations as well as to track changes as the temperature rises. Once structural parameters were determined from the established models, detailed information about the relative volume of each lamellar configuration was retrieved using energy-dispersive X-ray diffraction, a technique still poorly explored in Brazil. This allowed identifying the most stable configurations at high temperatures. The in-plane order of molecules was also studied using x-ray transmission geometry via a wide-angle x-ray scattering setup. Gathering the above mentioned information we have built phase diagrams depicting the lamellar and planar packing of OPA and OcPA molecules as a function of temperature. Finally, we have performed a study of the critical behavior of the ordered configurations in the vicinity of order-disorder transition temperatures for each molecule. The preliminary results explained in the final chapter of this work shed light into the short- and long-range order behavior of the two systems / Mestrado / Física / Mestre em Física

Abstract In this work an experimental study of size varied, neutral, and free metal clusters using synchrotron radiation excited photoelectron spectroscopy was performed. The combined core-level and valence photoelectron spectroscopic investigation indicates metallic properties for nanoscale Rb, K, Sn, and Bi clusters. In the case of Sn the experimental results suggest a metal-to-insulator transition occurring at the studied size range. In addition to the experimental results the technical implementation of the cluster production set-up is presented and jellium-model-based simulations are compared with the experimental results of the Rb and K clusters.

Prussian blue (PB) and Prussian blue analogues (PBAs) are compounds with potential applications in a large variety of fields such as gas storage, poison antidotes, electrochromism, electrochemistry and molecular magnets. The compounds are easy to synthesize, cheap, environmentally friendly and have been pursued for both fundamental research and industrial purposes. Despite the multifunctionality of PB and PBAs, they have complicated compositions, which are largely dependent on the synthesis methods and storage conditions. Thus, performing investigations on such compounds with defined composition, stoichiometry and crystal structure is essential. This thesis has focused on synthesis and detailed structure characterization of copper hexacyanoferrate (CuHCF) via X-ray powder diffraction (XRPD), neutron powder diffraction (NPD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), inductively coupled plasma-optical emission spectroscopy (ICP-OES), scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), Mössbauer spectroscopy, extended X-ray absorption fine structure (EXAFS), infrared (IR) and Raman techniques. In addition, kinetics of thermal dehydration process, CO2 adsorption and CO2 adsorption kinetics were investigated. Moreover, in operando synchrotron X-ray diffraction experiments were performed to gain insight into the structure-electrochemistry relationships in an aqueous CuHCF/Zn battery during operation. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 4: Manuscript. Paper 5: Manuscript.</p>

[pt] O processo de galvanização por imersão a quente é uma técnica industrial largamente utilizada para proteger componentes de aço expostos à corrosão ambiental. Este processo envolve reações complexas, cujos mecanismos ainda são motivo de debate. A boa performance do revestimento está diretamente relacionada com as fases intermetálicas presentes no revestimento final. Assim, o entendimento do mecanismo de nucleação e crescimento das fases durante a etapa de tratamento térmico contribui para a melhoria do processo, principalmente para redução de custos e desenvolvimento de novos produtos. No presente trabalho, a técnica MAXIM (Materials X-rays Imaging) foi utilizada para identificar as fases presentes em amostras galvanizadas submetidas a diferentes tratamentos. Um difratômetro equipado com um sistema de colimação e detecção formado por uma placa contendo microcanais (Micro-Channel Plate, MCP) situada em frente à uma câmera CCD, permite a obtenção de uma imagem de raios-X. Com esta técnica pode-se identificar a origem posicional do feixe difratado com resolução de cerca de 12mm. Foram realizados dois tipos de experimentos: (1) experimentos, à temperatura ambiente, que consistiam na observação de amostras galvanizadas previamente tratadas (2) experimentos de tratamento térmico in situ, onde a evolução das fases pode ser acompanhada em tempo real. Pode- se concluir que a técnica MAXIM, acoplada ao forno de tratamento térmico in situ, é um método eficiente de observar a distribuição e evolução das fases presentes nas amostras galvanizadas e galvannealed. Este técnica é sensível o suficiente para detectar a evolução das fases com boa resolução espacial. / [en] Galvannealing is an important commercial processing technique used to protect steel components exposed to corrosive environments. This process involves a number of complex reactions and their precise mechanisms are still a matter of debate. The good performance of the coating is closely related to the Fe-Zn intermetallic phases present in the coating. The understanding of the mechanisms for phase nucleation and growth during the galvannealing process is, therefore, essential to help improving current processes, mainly for cost reduction and new products development. In the present study, the MAXIM (MAterials Xrays Imaging) technique was used to identify the phases present in previously galvanized steel samples subjected to different annealing conditions. A diffractometer equipped with a novel imaging system comprising a micro-channel plate (MCP) in front of a CCD detector was used. This setup allows positionresolved X-ray diffraction investigation of materials, with a resolution of 12mm. The experiments involved two sets of conditions; (1) experiments based on the observation, at room temperature, of previously galvannealed samples. (2) in-situ annealing experiments, where the phase evolution was recorded in real time. It can be concluded that MAXIM, coupled to in-situ annealing, provides a useful method for observing the phase evolution and distribution in galvanized/galvannealed samples. The method is sensitive enough to detect the time/temperature evolution of these phases, with good spatial resolution.

Doctor of Philosophy / Department of Physics / Daniel Rolles / Imaging the structures of molecules, understanding the molecular dynamics in onization and dissociation processes and, most importantly, observing chemical reactions, i.e. the making and breaking of chemical bonds in real time, have become some of the most exciting topics in the atomic and molecular physics. The rapid advances of experimental tools such as synchrotron radiation light sources, free-electron lasers and continuing advances of tabletop femtosecond ultrashort lasers that provide laser pulses at a variety of wavelengths have opened new avenues for understanding the structure of matter and the dynamics of the chemical interactions. In addition, significant improvements in computational techniques and molecular dynamic simulations have provided complementary theoretical predictions on structures and chemical dynamics. The Coulomb explosion imaging method, which has been developed and applied in many studies in the last three decades, is a powerful way to study molecular structures. The method has mostly been applied to small diatomic molecules and to simple polyatomic molecules. In this thesis, Coulomb explosion imaging is applied to study the structure of isomers, molecules that have the same chemical formula but different chemical structures. Specifically, by taking inner-shell photoionization as well as strong-field ionization approaches to ionize and fragment the molecules and by using coincidence electron-ion-ion momentum imaging techniques to obtain the three-dimensional momentum of fragment ions, structures of isomers are distinguished by using the correlations among product ion momentum vectors. At first, the study aims to understand if the Coulomb explosion imaging of geometrical isomers can identify and separate cis and trans structures. Secondly, in order to extend the application of the Coulomb explosion imaging method to larger organic molecules to test the feasibility of the method for identifying structural isomers, photoionization studiesof 2,6- and 3,5-difluoroiodobenzene have been conducted. In addition, using the full three-dimensional kinematic information of multi-fold coincidence channels, breakup dynamics of both cis/trans geometric isomers and structural isomers, and in particular, sequential fragmentation dynamics of the difluoroiodobenzene isomers are studied. Furthermore, for each study, Coulomb explosion model simulations are conducted to complement the experimental results. The results of the Coulomb explosion imaging reseach in this thesis paves the way for future time-resolved Coulomb explosion imaging experiments aiming to understand the transient molecular dynamics such as photoinduced ring opening reactions and cis/trans isomerization processes in gas-phase molecules.

Doctor of Philosophy / Department of Biochemistry / Lawrence C. Davis / The fate and bioavailability of organic contaminants in plants is a major ecological and human health concern. Current wet chemistry techniques that employ strong chemical treatments and extractions with volatile solvents, such as GC-MS, HPLC, and radiolabeling, although helpful, degrade plant tissue resulting in the loss of spatial distribution and the production of artifacts. Synchrotron radiation infrared microspectroscopy (SR-IMS) permits direct analysis of plant cell wall architecture at the cellular level in situ, combining spatially localized information and chemical information from the IR absorbances to produce a chemical map that can be linked to a particular morphology or functional group. This study demonstrated the use of SR-IMS to probe biopolymers such as cellulose, lignin, and proteins in the root tissue of hydroponically grown sunflower and maize plants as well as to determine the fate and effect of several organic contaminants in those root tissues. Principal components analysis (PCA), a data compression technique, was employed to reveal the major spectral variances between untreated and organic contaminant treated root tissues. Treatment with 1H-benzotriazole (BT) caused alterations to the lignin component in the root tissue of plants. The BT was found in xylem and epidermal tissue of sunflower plants but not associated with any particular tissue in maize roots. 2,4-dinitrotoluene (2,4-DNT) and 2,6-dinitrotoluene (2,6-DNT) altered the pectin and polysaccharide structure in both maize and sunflower. SR-IMS revealed the reduction of DNTs to their aromatic amine form in the vascular and epidermal tissues at low concentration. At high concentration, DNTs appeared to be associated with all the plant tissues in maize and sunflower. Exposure of sunflower and maize to 2,6-dichlorophenol (2,6-DCP) caused alterations to the polysaccharide and protein component of the root tissue. In some cases, phenolic compounds were observed in the epidermal tissue of maize and sunflower roots. The results of this research indicate that SR-IMS has the potential to become an important analytical tool for determining the fate and effect of organic contaminants in plants.

This thesis describes the analysis of Very High Energy (VHE) emission from the Active Galactic Nucleus PKS 0537-441. It also aims to put the results in a wider context by implementing previous work done on this source. The data chosen for the analysis is provided by the Fermi-LAT satellite and covers the energy range between 300 MeV and 300 GeV. Initially a lightcurve of the received flux from the source was generated, containing data from August 2008 to April 2017, with a mean flux of 4∗10−8 photons per second per squared centimeter. The lightcurve contained sections of different flux intensities giving periods of special interest, such as a flaring period at August 2008 to August 2011, an enormous flare at April 2010 and a less active period between April 2013 - January 2016 that could be identified for further investigations. The differences in observed flux over time was tested and PKS 0537-441 was found to be a significantly variable source. Spectral Energy Distribution (SED) analysis was performed over both the entire period as well as over the selected subperiods and fitted against models using the tools provided by the Fermi Science Support Center (FSSC). The models used in the fitting was PowerLaw2, LogParabola and PLSuperExpCutoff and the best fit for the data was obtained from the PLSuperExpCutoff, except for the less intense period where the LogParabola gave the best fit. The result from the SED analysis was integrated with results from previous work done on the source, ranging over multiple wavelengths in order to get a SED which spanned over the entire electromagnetic spectrum. Finally, modeling of this multi wavelength SED was performed in order to obtain parameters for the physical processes involved in the creation of the radiation received from PKS 0537-441.

Abstract In this work, evolution of structural properties of anhydrous and hydrated alkali halide clusters are studied using synchrotron radiation based photoelectron spectroscopy. Alkali metal core level spectra of small anhydrous RbCl, RbBr, CsCl and CsBr clusters indicate a NaCl structure. For larger CsBr clusters a structural phase transition to CsCl structure is likely the case. Alkali halide core level spectra of mixed RbBr-water clusters indicate that at dilute concentration the salt is dissolved by the water cluster but ion pairing increases with concentration. Modeling of gas phase cluster formation and electronic structure calculations of core level chemical shifts are used to interpret the experimental spectra.

Röntgenmikroskopie ist in den vergangenen Jahren zu einer leistungsfähigen und vielseitigen bildgebenden Methode in vielen Bereiche der Wissenschaft geworden, mit der opake Medien bei hoher räumlicher Auflösung untersucht werden können. Es bleibt jedoch eine Herausforderung, geeignete Röntgenlinsen herzustellen, wie z.B. Frsenlesche Zonenplatten oder refraktive Linsen. In einem alternativen Ansatz linsenloser Abbildung wird die Probe mit kohärenter Röntgenstrahlung beleuchtet. Die Probeninformation wird dann aus dem aufgenommenen Streubild durch numerische, iterative Algorithmen rekonstruiert. In dieser Arbeit wird zunächst die Grundlage von linsenloser holographischer Abbildung mit Röntgenwellenleitern erläutert und zu einem Konzept der Röntgeninterferometrie mit Wellenleitern erweitert. Die spezifische Instrumentierung, die erforderlich war für Demonstrationsexperimente mit Röntgenwellenleitern zur holographischen Abbildung, wird erklärt und die erzielten Ergebnisse präsentiert. Basierend auf diesen Ergebnissen der Demonstrationsexperimente wurde ein Instrument zur holographischen Abbildung mit Röntgenwellenleitern entwickelt und aufgebaut. Die Spezifikationen und Eigenschaften des Kirckpatrick-Beaz Spiegelsystems und anderen mechanischen und optischen Komponenten werden beschrieben und experimentell charakterisiert, zusammen mit dem Steuerungssystem und verschiedenen verfügbaren Detektoren. Erste Ergebnisse belegen die hohe Abbildungsqualität des vorgestellten Instruments.