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1
Kóta, J., and J. R. Jokipii. "Transient Cosmic-ray Events beyond the Heliopause: Interpreting Voyager-1 Observations." IOP PUBLISHING LTD, 2017. http://hdl.handle.net/10150/624725.
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In 2013 March and 2014 May, Voyager-1 (V1) experienced small but significant increases in the flux of galactic cosmic rays (GCRs) in the hundred MeV/n range. Additionally, V1 also saw episodic depletion of GCR flux around perpendicular pitch angles. We discuss the pitch-angle distribution and the time profiles of these events. In a previous paper, we interpreted the 2013 "bump" as the GCRs remotely sensing a shock that reached the magnetic field line passing through V1: particles gained energy as they were reflected on the approaching region of the stronger magnetic field of the disturbance. Here, we point out that energy gain is not restricted to reflected particles -GCRs passing through the disturbance also gain energy. The effect should be present in a broad range of pitch angles with the maximum increase of GCR intensity predicted to occur at the critical reflection angle. In this paper, the shock is not step-like, but a gradual increase of the magnetic field strength, B, taking a few days, in agreement with V1 measurements. This smoothens the profile of the predicted bump in the GCR flux. We also address the linear episodic decreases seen around perpendicular pitch angles. These events are interpreted in terms of adiabatic cooling behind the shock due to the slow weakening of B. We present simple numerical model calculations and find that a gradual shock followed by a slow decrease of B, as observed, may account for both the episodic increases and the anisotropic depletion of GCR fluxes.
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O'Dwyer, Brendan. "EUV & X-ray spectroscopic diagnostics of the solar corona." Thesis, University of Cambridge, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.610731.
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Miyake, Fusa, A. J. Timothy Jull, Irina P. Panyushkina, Lukas Wacker, Matthew Salzer, Christopher H. Baisan, Todd Lange, Richard Cruz, Kimiaki Masuda, and Toshio Nakamura. "Large 14C excursion in 5480 BC indicates an abnormal sun in the mid-Holocene." NATL ACAD SCIENCES, 2017. http://hdl.handle.net/10150/623129.
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Radiocarbon content in tree-rings can be an excellent proxy of the past incoming
cosmic ray intensities to the Earth. Although such past cosmic ray variations have
been studied by measurements of 14C contents in tree rings with ≧10 year time
resolution for the Holocene (1), there are few annual 14C data. There is a little
understanding about annual 14C variations in the past with the exception of a few
periods including the AD774-775 annual 14C excursion (2).
Here, we report the result of 14C measurements using the bristlecone pine tree rings
for the period from 5490 BC to 5411 BC with 1-2 year resolution, and a finding of an
extraordinarily large 14C increase (20‰) from 5481 BC to 5471 BC (the 5480 BC
event). The 14C increase rate of this event is much larger than that of the normal
Grand Solar Minima. We propose the possible causes of this event are a special
phase of grand solar minimum, or a combination of successive solar proton events
and a normal grand solar minimum.
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Mathur, Abhishek, and n/a. "Multi Agents for Heterogeneous Operating System Environments." University of Canberra. Information Sciences & Engineering, 2007. http://erl.canberra.edu.au./public/adt-AUC20070810.090108.
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As IT industries develop, upgrade and diversify, heterogeneous operating
environments running a mix of new and legacy systems become increasingly
important. Such environments are currently inadequate due to lack of compatibility
with each other. This thesis investigates how agents can be utilised to facilitate
such heterogeneous environments, aiding enterprise systems in building bridges
between incompatible software and hardware systems. An autonomous agent has
independent agency and decision-making astuteness. When placed in
heterogeneous environments to interact with other such agents, the consequences of
its action and its preferred choice of actions are greatly influenced by actions of
other agents interacting in heterogeneous environments.
The main objectives of this thesis include examining the roles of agents in
heterogeneous operating environments, development of a novel multi agent base
architecture and an associated framework for single and heterogeneous
environment. The research work also studies the plausible application to test the
developed proof of concept by developing application and using the framework
that utilises Windows services in a totally incompatible Solaris based Sun Ray ultra
thin client environment.
The work includes a novel method of modeling agent based communication
architecture suitable for correspondence between two inherently different operating
systems - Solaris and Microsoft Windows. The circumstances in which
coordination or coordination failure occurs between these systems are investigated.
The proposed method of agent based communication that can potentially overcome
the barriers formed by two completely different software and hardware
architectural regimes.
An analysis of printing services in MS Windows and Solaris environments, review
the age long problem of lack of device drivers for commonly (and cheaply)
available Ink Jet printers for Unix (and like) operating systems. A novel method is
proposed that uses agents in heterogeneous environment to overcome this problem.
A new architecture that utilises Windows based printing services on a Sun Ray
ultra thin client is presented to test and evaluate the proof of concept.
This thesis is motivated by the need to provide a low cost printing solution to Sun
Ray users. Most Windows based desktop users currently have access to variety of
low cost printing solutions. Printer vendors ship device drivers only for Windows
or at most Macintosh, as other operating systems such as Solaris, MVS, z/OS are
used for corporate solutions and low cost desktop printing have not been a major
requirement in the past.
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Meehan, Patrick James. "Development of a Water Cloud Radiance Model for Use in Training an Artificial Neural Network to Recover Cloud Properties from Sun Photometer Observations." Thesis, Virginia Tech, 2021. http://hdl.handle.net/10919/103742.
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As the planetary climate continues to evolve, it is important to build an accurate long-term climate record. State-of-the-art atmospheric science requires a variety of approaches to the measurement of the atmospheric structure and composition. This thesis supports the possibility of inferring cloud properties from sun photometer observations of the cloud solar aureole using an artificial neural network (ANN). Training of an ANN requires a large number of input and output parameter sets. A cloud radiance model is derived that takes into consideration the cloud depth, the mean size of the cloud water particles, and the cloud liquid water content. The cloud radiance model derived here is capable of considering the wavelength of the incident sunlight and the cloud lateral dimensions as parameters; however, here we consider only one wavelength—550 nm—and one lateral dimension—500 m—to demonstrate its performance. The cloud radiance model is then used to generate solar aureole profiles corresponding to the cloud parameters as they would be observed using a sun photometer. Coefficients representative of the solar aureole profiles may then be used as inputs to a trained ANN to infer the parameters used to generate the profile. This process is demonstrated through examples. A manuscript submitted for possible publication based on an early version of the cloud radiance model was deemed naïve by reviewers, ultimately leading to improvements documented here.Master of Science
The Earth's climate is driven by heat from the sun and the exchange of heat between the Earth and space. The role of clouds is paramount in this process. One aspect of "cloud forcing" is cloud structure and composition. Required measures may be obtained by satellite or surface-based observations. Described here is the creation of a numerical model that calculates the disposition of individual bundles of light within water clouds. The clouds created in the model are all described by the mean size of the cloud water droplets, the amount of water in the cloud, and cloud depth. Changing these factors relative to each other changes the amount of light that traverses the cloud and the angle at which the individual bundles of light leave the cloud as measured using a device called a sun photometer. The measured amount and angle of bundles of light leaving the cloud are used to recover the parameters that characterize the cloud; i.e., the size of the cloud water droplets, the amount of water in the cloud, and the cloud depth. Two versions of the cloud radiance model are described.
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Salas, Matamoros Carolina. "Radio and X-ray studies of Coronal Mass Ejections and their relevance for Space Weather." Thesis, Paris Sciences et Lettres (ComUE), 2016. http://www.theses.fr/2016PSLEO016/document.
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La couronne solaire est un milieu très dynamique : instabilités du champ magnétique, qui structure le plasma, conduit à l'accélération et le chauffage des particules chargées et à l'éjection de grandes structures dans l'héliosphère, les émissions de masse coronale (CME, selon ces sigles en anglais). Ces structures magnétiques éjectées peuvent interagir avec le champ magnétique de la Terre et affecter le plasma de l'environnement. Ces structures conduisent également à l'induction des courants électriques dans le sol à des latitudes élevées. L'étude de l'origine et de la propagation de ces émissions est d'intérêt pour l’astrophysique dans l’encadre des applications générales et pour la météorologie de l’espace. La compréhension des processus de base est une condition importante pour l'élaboration des méthodes de prévision des arrivées de ces perturbations en utilisant des observations de la couronne solaire. Les CMEs sont observées et étudiées à travers des images coronographiques. La limitation fondamentale du coronographe est qu'il montre la couronne seulement dans le plan du ciel, donc il bloque, forcément, la vue sur le disque solaire. Mais le geoefficacité d'une CME dépend essentiellement de la proximité à la ligne Soleil- Terre et de l'évolution dans la basse couronne que ne sont pas visibles à travers des observations coronographiques. Un des problèmes est la difficulté d’estimer l'arrivée d'une CME à la Terre, parce que les mesures avec coronographes directes de la vitesse de propagation des CMEs qui est dirigée vers la Terre ne sont pas possibles dans la ligne Soleil-Terre. Cette thèse présente l'étude des CMEs en trois étapes : (1) une étude de cas de l'évolution CME dans la bassecouronne et son rôle dans l'accélération des particules, (2) la relation entre la polarisation de l'émission de sursauts radio de type IV associées à CMEs dans la couronne et l'orientation du champ magnétique observé quand les CMEs arrivent à la Terre, et (3) des estimations radiatives de la vitesse des CMEs pour les prévisions des temps d’arrivée des CMEs à la Terre. Imagerie en utilisant des émissions radio dans la basse couronna peut montrer les signatures des CMEs sur le disque solaire. Des études précédentes avec le Radiohéliographe de Nançay (NRH) suggèrent, en fait, que les images de radio aux longueurs d'onde métriques peuvent suivre l'évolution des CMEs bien avant qu'ils deviennent visibles dans la couronne. Le diagnostic de l'évolution CME dans la basse couronne développée dans ce travail a été illustrée par l'étude de l'événement éruptif du 26 Avril 2008, qui a offert une occasion unique d'étudier le lien physique entre une seule CME bien identifiée, l'accélération des électrons tracé par émission radio, ainsi que la production des particules énergétiques solaires (SEP, selon ces sigles en anglais) observées dans l'espace. Nous effectuons une analyse détaillée en combinant les observations radio (NRH et DAM, Wind / WAVES spectrographe) et les observations de la couronne avec des satellites dans EUV et lumière blanche, ainsi que des mesures ‘in situ’ des particules énergétiques près de 1UA (satellites SoHO et STEREO). En combinant des images prises à partir de plusieurs points de vue, nous avons pu déduire l'évolution 3D en fonction du temps du front de l’éjection de mass qui s’est développée autour de l’éruption de la CME. Enfin, nous avons identifié, à partir des observations radio et SEP, trois régions différentes d'accélération des particules associées à l'évolution de la même CME, séparés en longitude environ 140°The solar corona is a highly dynamical medium: instabilities of the magnetic field, which structure the plasma, lead to the acceleration and heating ofcharged particles and to the ejection of large structures into the heliosphere, the Coronal Mass Ejections (CMEs). These ejected magnetic structures can interact with the Earth's magnetic field and thereby affect the plasma environment and the high atmosphere of the Earth. Studying the origin and propagation of CMEs is of interest for both astrophysics in general and space weather applications. The understanding of the basic processes is indeed a pre-requisite for developing prediction methods of potentially geo-effective disturbances based on observations of the solar corona.The CMEs are observed and studied primarily through coronographic images. The basic limitation of the coronagraph is that it shows the corona only in the plane of the sky, and blocks by necessity the view on the solar disk. But the geoeffectiveness of a CME depends crucially on the proximity to the Sun-Earth line and the measurements of the propagation speed, onset and early evolution of CMEs in the low corona are not accessible to coronographic observations. This thesis presents the study of CMEs in three different stages: (1) a case study of the CME evolution in the low corona and of its role in particle acceleration, (2) the relationship between the polarisation of the type IV radio emission associated with Earth-directed CMEs in the corona and the orientation of the magnetic field observed as the CMEs arrive at the Earth, and (3) the estimation of the travel times of CMEs to the Earth. Radio imaging with the Nancay Radioheliograph (NRH) suggest that radio images at metric wavelengths track the early evolution of CMEs well before they become visible in the corona. The examination of the CME evolution in the low corona developed in this work was illustrated through the study of the eruptive event on 26 April 2008, which offered a unique opportunity to investigate the physical link between a single well-identified CME, electron acceleration as traced by radio emission, and the production of solar energetic particles (SEPs) observed in space. We conduct a detailed analysis combining radio observations (NRH and Decameter Array, Wind/WAVES spectrograph) with remote-sensing observations of the corona in extreme ultraviolet (EUV) and white light as well as in-situ measurements of energetic particles near 1AU (SoHO and STEREO spacecraft). By combining images taken from multiple vantage points we were able to derive the time-dependent evolution of the 3D pressure front developing around the erupting CME. Finally, we identified, from the radio and SEP observations, three different particle acceleration regions associated to the evolution of the same CME, separated in longitude by about 140$^\circ$. The observations for this event showed that it is misleading to interpret multi-spacecraft SEP measurements in terms of one acceleration region in the corona
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Sun, Fu [Verfasser], John [Akademischer Betreuer] Banhart, John [Gutachter] Banhart, and Yan [Gutachter] Lu. "X-ray radiographic and tomographic investigations of cycled lithium ion batteries / Fu Sun ; Gutachter: John Banhart, Yan Lu ; Betreuer: John Banhart." Berlin : Technische Universität Berlin, 2017. http://d-nb.info/1156180074/34.
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Törnros, Martin. "Interactive visualization of space weather data." Thesis, Linköpings universitet, Medie- och Informationsteknik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-101986.
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This work serves to present the background, approach, and selected results for the initial master thesis and prototyping phase of Open Space, a joint visualization software development project by National Aeronautics and Space Administration (NASA), Linköping University (LiU) and the American Museum of Natural History (AMNH). The thesis report provides a theoretical introduction to heliophysics, modeling of space weather events, volumetric rendering, and an understanding of how these relate in the bigger scope of Open Space. A set of visualization tools that are currently used at NASA and AMNH are presented and discussed. These tools are used to visualize global heliosphere models, both for scientific studies and for public presentations, and are mainly making use of geometric rendering techniques. The paper will, in detail, describe a new approach to visualize the science models with volumetric rendering to better represent the volumetric structure of the data. Custom processors have been developed for the open source volumetric rendering engine Voreen, to load and visualize science models provided by the Community Coordinated Modeling Center (CCMC) at NASA Goddard Space Flight Center (GSFC). Selected parts of the code are presented by C++ code examples. To best represent models that are defined in non-Cartesian space, a new approach to volumetric rendering is presented and discussed. Compared to the traditional approach of transforming such models to Cartesian space, this new approach performs no such model transformations, and thus minimizes the amount of empty voxels and introduces less interpolation artifacts. Final results are presented as rendered images and are discussed from a scientific visualization perspective, taking into account the physics representation, potential rendering artifacts, and the rendering performance.
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Tenholt, Frederik [Verfasser], Julia [Gutachter] Tjus, and Horst [Gutachter] Fichtner. "Studying the temporal variation of the cosmic-ray sun shadow : comparison of IceCube data with models of the solar magnetic field / Frederik Tenholt ; Gutachter: Julia Tjus, Horst Fichtner ; Fakultät für Physik und Astronomie." Bochum : Ruhr-Universität Bochum, 2020. http://d-nb.info/1205976329/34.
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Tenholt, Frederik Josef [Verfasser], Julia [Gutachter] Tjus, and Horst [Gutachter] Fichtner. "Studying the temporal variation of the cosmic-ray sun shadow : comparison of IceCube data with models of the solar magnetic field / Frederik Tenholt ; Gutachter: Julia Tjus, Horst Fichtner ; Fakultät für Physik und Astronomie." Bochum : Ruhr-Universität Bochum, 2020. http://d-nb.info/1205976329/34.
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Armakan, Elvan Yardımoğlu Bülent. "Analysis of two-axis sun tracking system/." [s.l.]: [s.n.], 2003. http://library.iyte.edu.tr/tezler/master/enerjimuh/T000260.rar.
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COKER, NATHAN LEE. "THE SYNTHESES AND CHARACTERIZATIONS OF THE VARIOUS SALTS OF [Au(SCN) 2 ] -." University of Cincinnati / OhioLINK, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1053453898.
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Huss, Niklas. "Real Time Ray Tracing." Thesis, Linnéuniversitetet, Institutionen för datavetenskap, fysik och matematik, DFM, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-9207.
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Ray tracing has for a long time been used to create photo realistic images, but due to complex calculations done per pixel and slow hardware, the time to render a frame has been counted in hours or even days and this can be drawback if a change of a scene cannot be seen instantly. When ray tracing a frame takes less than a second to render we call it “real time ray tracing” or “interactive ray tracing” and many solutions have been developed and some involves distributing the computation to different computers interconnected in a very fast network (100 Mbit or higher). There are some drawbacks with this approach because most people do not have more than one computer and if they have, the computers are most likely not connected to each other. Since the hardware of today is fast enough to render a pretty complex image within minutes it should be possible to achieve real time ray tracing by combining many different methods that has been developed and reduce the render time. This work will examine what has to be sacrificed in image quality and complexity of static scenes, in order to achieve real time frame rate with ray tracing on a single computer. Some of the methods that will be covered in this work are frame optimizations, secondary rays optimization, hierarchies, culling, shadow caching, and sub sampling.
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Lucy, Jeremy M. "Exploration and Engineering of Physical Properties in High-Quality Sr2CrReO6 Epitaxial Films." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1436888316.
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Gates, Stacy D. "Cation Influence on Negative Thermal Expansion in the A2M3O12 Family." University of Toledo / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1216698704.
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Käämbre, Tanel. "Resonant Soft X-ray Spectroscopic Studies of C60 and Related Materials." Doctoral thesis, Uppsala University, Department of Physics, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-1634.
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This thesis addresses the electronic structure of molecular and correlated solids using resonant inelastic soft X-ray scattering (RIXS), non-resonant X-ray emission, photoemissionand X-ray absorption spectroscopies. The use of monochromatised synchrotron radiation and improved energy resolution for X-ray emission have made it possible to elucidate the normal state transport properties and to get further insight into the electron-vibration coupling in fullerenes and the related compounds. The latter is particularly important in order to understand the physical mechanism of superconductivity in fullerene materials. The characteristic intermolecular charge transfer times in K3C60 are found to be longer than the X-ray scattering time-scale (a few femtoseconds). The slow intermolecular charge transport emphasizes that the reduced fullerene compounds can not be treated as simple metals, but rather as systems with strong electron correlation. The electron structure and the bonding character of the more covalent transition metal (V, Ti, Nb) fullerides have been addressed. Evidence indicating the existence of chemical bond between the metal atom(s) and C60 is presented, and the nature of the bond is discussed by comparing RIXS spectroscopic measurements and theoretical predictions. The (crystal) momentum conservation is discussed by comparing the spectroscopic data of a quasi-1D (carbon nanotubes) and quasi-2D (graphite) systems. Finally, the intra-atomic electron-electron correlation is discussed in the case of double core-hole state photo-excitation and de-excitation processes. RIXS including intermediate states with two core vacancies has been observed for the first time in the soft X-ray region.
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Correia, Adriano Melo. "Estudo comparativo do posicionamento acetabular e sua relação com osteoartrite primária do quadril." Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/5/5140/tde-16022009-174150/.
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O presente estudo destinou-se a realizar uma análise comparativa entre a osteoartrite de quadris e o posicionamento acetabular através de exames radiográficos e de tomografia computadorizada. Foram incluídos 13 pacientes portadores e oito não-portadores de osteoartrite primária do quadril, recrutados no Ambulatório do Instituto de Ortopedia e Traumatologia do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo. Os exames foram submetidos à medição das seguintes variáveis: ângulos acetabulares, ângulo centro-borda, sinal do entrecruzamento, largura e profundidade do acetábulo no RX; anteversão e ângulos setoriais acetabulares nos tomogramas. Não se verificou diferença estatisticamente significatova na anteversão acetabular entre ambos os grupos, ao passo que o ângulo acetabular setorial posterior mostrou média inferior no grupo afetadoThe present study intends to develop a comparative analysis between primary hip osteoarthritis and acetabular positioning through x-ray exams and computed tomographic scans. 13 affected and 8 non-affected patients by degenerative hip disease with no underline causes are recruited within the ambulatory care service of the Institute of Orthopedics and Traumatology of the Hospital of Clinics, São Paulo University Medical School. Their radiographic exams are studied for extracting some parameters named as: acetabular angles, center edge angle, crossover sign, acetabular width and acetabular depth. Tomographic films give information to measure acetabular ante version and acetabular setorial angles. Statistically, there is no significant relationship concerning acetabular ante version within the two groups, although, the posterior acetabular setorial angle shows a lower median value in the osteoarthritic group
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Pape, Ian. "Measurement of surface and sub-surface damage by X-ray scattering." Thesis, Durham University, 1997. http://etheses.dur.ac.uk/4752/.
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The study of surface and interface structure of thin film devices is becoming increasingly important in industrial applications today. In this thesis, the technique of grazing incidence x-ray scattering (GEXS) is developed and its validity examined for many different materials. In addition, the technique of Born wave analysis introduced by Lagally has been extended, showing that in certain cases surface roughness can be obtained without full simulations of the data. GEXS measurements performed on float glass revealed that the density of the tin and air sides were 2.7 ± 1 and 2.3 ± 1 g/cc respectively across the entire ribbon. For all samples studied a surface layer on the order of a few nanometers was in evidence. When similar measurements were made on container glass it was seen to be layer free. In addition, excellent agreement was found between the roughness deduced from the simulations and the Born wave analysis. In all samples, the surface roughness deduced from the diffuse scatter was less than that from the specular, indicating that a vertical density gradient was present. When x-ray scattering measurements were performed on CVD layers deposited on glass it was noted that two sets of Yoneda wings existed in the diffuse scatter. From these it was concluded that lateral density variations existed in the SnO(_2) layer which were on the order of 0.5mm in diameter. Furthermore, excellent specular simulations were obtained. These indicated that the control of both layer thickness and interface roughness between samples was on the Angstrom level. Specular and diffuse x-ray scattering measurements were performed on Cu/Co multilayers grown on sapphire using a Nb buffer. Here the effect of anomalous dispersion was employed in order to highlight the scattering from the Cu/Co interfaces. From these data Born wave analysis was used to characterise the roughness of the samples. It was found that little change took place for anneals of 45 minutes at temperatures up to 300 C. In addition, it would appear that the measured OMR bore no relationship to the component of uncorrelated roughness within the samples. GIXS measurements perfumed on Cu/Co multilayers grown on Si, using a Cu(_3)Si buffer, revealed an asymmetry in the diffuse scatter, which was attributed to terracing within the layers. Simulations were obtained to the data using a slight modification of the fractal model for several scattering vectors with a single set of parameters. From this, a model of step bunching has been proposed which allows the diffuse scatter to be described using such a fractal surface. Diffuse x-ray scattering studies performed on Al(_2)O(_3), which had been ground in different ways, indicted that the surface density as measured from the Yoneda wings followed the bearing area as measured from optical techniques. Comparisons performed between these results and those from optical microscopy and surface acoustic wave techniques allowed a model to be proposed which was consistent with all the findings. Finally, GIXS measurements were performed on GaAs which had been subjected to various polishing techniques. Simulations revealed that a nanometer scale surface layer was present on all samples. Born wave analysis was successfully applied to the diffuse scatter and the effect of surface layers on the deduced roughness was investigated. In addition, symmetric and asymmetric triple axis diffraction studies revealed that the distribution of strains was independent of the type of polishing used whereas the tilts were not. A model has been proposed in which the surface consists of unstrained mosaic blocks separated by cracks.
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Drew, Richard John. "An investigation into sub-surface strain measurement using X-ray radioscopy." Thesis, Loughborough University, 1999. https://dspace.lboro.ac.uk/2134/33075.
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There are numerous techniques used to measure strain. Most are only capable of taking surface measurements. The penetrating nature of X-rays has been used to measure deformation, and thus strain, but only with radiographic images. Radioscopic techniques are faster and do not require film processing, but produce less detailed results than digitised radiographic images. The research covered by this thesis tested radioscopic images and showed them to be suitable for strain measurement. The thesis includes details of the design and capabilities of the radioscopic equipment. Pin cushion distortion is a common feature of radioscopic images, and an automatic method of identifying, and correcting for the distortion was implemented.
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Harrod, Steven B., Ryan T. Lacy, Jun Zhu, Benjamin A. Hughes, Marla K. Perna, and Russell W. Brown. "Gestational IV Nicotine Produces Elevated Brain-Derived Neurotrophic Factor in the Mesocorticolimbic Dopamine System of Adolescent Rat Offspring." Digital Commons @ East Tennessee State University, 2011. https://doi.org/10.1002/syn.20975.
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Maternal smoking during pregnancy is associated with enduring psychopathology, such as increased likelihood of substance use, in offspring. Various animal models demonstrate that continuous nicotine exposure produces teratogenic effects in offspring, as well. In this experiment, a novel intravenous (IV) exposure model was used to determine if gestational nicotine (GN) treatment produced alterations in methamphetamine-induced sensitization and the expression of brain-derived neurotrophic factor (BDNF) in the mesocorticolimbic dopamine (DA) system of adolescent offspring. Dams were injected with IV saline or nicotine (0.05 mg/kg/injection) three times per day on gestational days 8-21. Habituation was measured on postnatal day (PND) 25-27 and baseline activity on PND 28. On PND 29-35, offspring were injected with saline or methamphetamine (0.3 mg/kg) and locomotor activity was measured after the first and seventh injections. On PND 36, brains were removed, flash frozen, and BDNF protein levels in the nucleus accumbens (NAcc), dorsal striatum (Str), frontal cortex (FC), and hippocampus (Hipp) were analyzed. GN did not affect habituation or the induction of methamphetamine-induced sensitization. Interestingly, GN, but not adolescent methamphetamine treatment, elevated levels of BDNF in the NAcc and Str; however, the GN-induced increase in BDNF in the FC was attenuated by adolescent methamphetamine treatment. Both GN and adolescent methamphetamine treatment increased BDNF in the Hipp. These findings indicate that GN exposure will result in increased levels of BDNF protein throughout the mesocorticolimbic DA system during adolescent development and suggests that methamphetamine abuse will modulate the expression of BDNF in motivational circuitries of adolescent offspring exposed to GN.
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Bordas, Mariano. "Possibilites offertes par l'utilisation simultanee des methodes pixe (particle induces x-ray emission) et pige (particle induced gamma-ray emission) en analyse elementaire." Université Louis Pasteur (Strasbourg) (1971-2008), 1988. http://www.theses.fr/1988STR13009.
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Kristjánsson, Sveinbjörn. "Skin cancer prevention : readiness to change sun-related behaviours /." Stockholm, 2004. http://diss.kib.ki.se/2004/91-7349-895-5/.
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Wilson, Ross C. "Structure and Function in Archaeal RNase P and the SMK Box Riboswitch." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1260765086.
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RODRIGUES, KATIA C. "Caracterizacao cristalina e magnetica de precipitados de magnetita obtidos na preparacao do ferrofluido Fe sub(3) O sub(4) + D sub(2)O." reponame:Repositório Institucional do IPEN, 1994. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10386.
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Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
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Schiessling, Joachim. "Angle-Dependent Electron Spectroscopy Studies of C60 Compounds and Carbon Nanotubes." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-3595.
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Diss. (sammanfattning) Uppsala : Univ., 2003.Härtill 8 uppsatser. På titelsidan feltryck av serietitel: Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology.
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Poppi, Francesco. "The cosmic ray tagger of the short baseline neutrino experiment at Fermilab." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amslaurea.unibo.it/19306/.
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The Short Baseline Neutrino (SBN) program at Fermilab will search for new physics in the neutrino oscillations parameters. The far detector will be interested by a ~25 kHz rate of cosmic ray events. An external cosmic ray tagging system will be implemented in order to prevent possible misidentification in the liquid argon time projection chamber.
This thesis is focused on the activities performed on the top cosmic ray tagging modules of the SBN experiment. The front-end electronics and the data acquisition software were tested and debugged. The performance evaluation techniques were first developed on the prototype module in Bologna and then applied to the assembled modules at the Frascati National Laboratories.
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Bränström, Richard. "Skin cancer prevention : behaviours related to sun exposure and early detection /." Stockholm, 2003. http://diss.kib.ki.se/2003/91-7349-550-6/.
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Carter, David John Donat 1966. "Sub-50nm x-ray lithography with application to a coupled quantum dot device." Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/50037.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1998.Includes bibliographical references (p. 214-231).
by David John Donat Carter.
Ph.D.
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Karlsson, Linus. "Optimering av sampling quality-parametrar för Mental Ray." Thesis, Högskolan i Gävle, Avdelningen för Industriell utveckling, IT och Samhällsbyggnad, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-10099.
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Fotorealistiska 3d-bilder används idag inom ett brett spektrum av branscher. Framställningen av denna typ av grafik kräver ofta väldigt mycket datorkraft. Vid rendering med renderingsmotorer som använder sig av raytracing algoritmer är aliasing ett medfött problem. Lösningen heter anti-aliasing som arbetar för att undvika aliasing artefakter som jagged edges eller Moiré-effekter med mera. En del av anti-aliasingprocessen är supersampling som ofta kräver mycket datorkraft. Att optimera parametrar för supersampling är därför mycket viktigt. Det är möjligt att genom optimering spara väldigt mycket datorkraft och därmed tid. Detta arbete innehåller resultat från experiment där deltagare får bedöma bilder med olika kvalité av anti-aliasing. Resultaten av dessa experiment kan användas som referens vid optimering av renderingsparametrar för anti-aliasing vid rendering med hjälp av Mental Ray.
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Komura, Shotaro. "Imaging Polarimeter for a Sub-MeV Gamma-Ray All-sky Survey Using an Electron-tracking Compton Camera." Kyoto University, 2018. http://hdl.handle.net/2433/230989.
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Sjögren, Tove. "Structural Plasticity and Function in Cytochrome cd1 Nitrite Reductase." Doctoral thesis, Uppsala University, Department of Biochemistry, 2001. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-1394.
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Cytochrome cd1 nitrite reductase is a bifunctional enzyme, which catalyses the one-electron reduction of nitrite to nitric oxide, and the four-electron reduction of oxygen to water. The latter is a cytochrome oxidase reaction. Both reactions occur on the d1 haem iron of the enzyme.
Time resolved crystallographic studies presented here show that the mechanisms of nitrite and oxygen reduction share common elements. This is of interest from an evolutionary point of view since aerobic respiratory enzymes are thought to have evolved from denitrifying enzymes. Despite of similarities, the results also imply different requirements for the timing of electron transfer to the active site in these reactions.
Quantum chemical calculations suggest that nitric oxide, the product of nitrite reduction, is not spontaneously released from the haem iron while this is not the case with water. Reduction of the haem while nitric oxide is still bound to it would result in a tight dead-end complex. A mechanism must therefore exist for the selective control of electron transfer during the reaction.
Structural studies with a product analogue (carbon monoxide) combined with flash photolysis of the complex in solution revealed an unexpected proton uptake by the active site as the neutral CO molecule left the enzyme. This led to the suggestion that the increased positive potential of the active site triggers preferential electron transfer when the active site is empty.
Crystallisation and structure determination of the reduced enzyme revealed extremely large domain rearrangements. These results offer insights into the role of tethered electron shuttle proteins in complex redox systems, and suggests a mechanism for conformational gating in catalysis.
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Parker, Cody E. "The ³H(d,γ) Reaction and the ³H(d,γ)/ ³H(d,n) Branching Ratio for Ec.m. ≤ 300 keV." Ohio University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1471366054.
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Balenderan, Shangkari. "On the connection between the γ-ray and (sub-)mm emission in active galactic nuclei." Thesis, Durham University, 2016. http://etheses.dur.ac.uk/11934/.
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This research investigates the connection between the submillimetre (sub-mm), millimetre (mm) and gamma-ray emission in a sample eight blazars (consisting of high- and intermediate-frequency peaked BL Lacertae Objects (HBLs and IBLs respectively) as well as Flat Spectrum Radio Quasars (FSRQs)) and one radio galaxy. Light curves using both short-term (~6 days to ~3 months) and long-term (5.5 - 12 years) observations at gamma-ray and (sub-)mm wavebands are presented. Long-term light curves at (sub-)mm wavelengths show evidence that emission at these wavelengths is source class dependent. Similarities in emission patterns and flux variability were observed between FSRQs and IBLs. The correlation between emission at 1.35 mm and the 100 MeV to 100 GeV gamma-ray wavebands was studied both qualitatively and statistically using the discrete correlation function (DCF) method. Results from the DCF analysis showed that while all sources exhibit different behavioural patterns at different epochs, some general trends can be drawn based on the source type. It was found that IBLs behaved more like FSRQs than HBLs, although IBLs are classified as BL Lacertae objects, with HBLs showing the weakest correlation and variability at both emission bands and FSRQs showing the strongest evidence for correlation and variability within this sample set. This provides further evidence for the hypothesis of the unified Active Galactic Nuclei model, in which these objects evolve from FSRQ type blazars into IBLs and then into HBLs. This is because IBLs exhibit behavioural patterns of both FSRQs and BL Lacertae objects. In addition to this, time delay analysis of 3C 454.3, BL Lacertae and 3C 273 in the correlation study yielded separation distances between the emission regions ranging between ~0.1 pc to ~19 pc in the rest frame of the observer. These are in agreement with other studies in the literature (e.g. (214;42)). However, much greater separation distances were observed for 3C 279 and OJ 287 (> 70 pc). These findings suggest that the nature and geometry of blazar jets are highly complex and vary from epoch to epoch. It was concluded that extensive consistent long-term multiwavelength studies of a larger sample of sources from all blazar sub-classes would help further constrain the location of the wavelength-dependent emission regions in the jet.
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Barbosa, Eder Queiroz [UNESP]. "Calibração de detectores cintiladores e sua aplicação em medidas radiométricas." Universidade Estadual Paulista (UNESP), 2016. http://hdl.handle.net/11449/151412.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
O presente trabalho descreve etapas realizadas para a viabilização de novas metodologias de calibração de sistemas radiométricos portáteis utilizados no LABIDRO (Laboratório de Isótopos e Hidroquímica) do DPM (Departamento de Petrologia e Metalogenia) do IGCE (Instituto de Geociências e Ciências Exatas) da UNESP, Campus de Rio Claro. Dentre os tópicos abordados estão a determinação de tempos de detecção de maior precisão, curvas de calibração dosimétrica e a aquisição de dados de dosimetria no ar, para ambientes indoor e outdoor, por intermédio de gamaespectrômetros portáteis. Os modelos geoestatísticos gerados a partir da conversão de dados em dose efetiva para os locais analisados nos departamentos do Curso de Geologia da UNESP de Rio Claro (SP), demonstraram que apesar de existirem alguns valores situados acima daqueles recomendados pela ICRP e norma CNEN-NN-3.01 de 1 mSv.ano-1, não há a necessidade de intervenção nos locais onde ocorreram (Museu Heinz Ebert; Litoteca do DPM) pois, não são de uso frequente e, além disso, situam-se abaixo do limite recomendado de 20 mSv.ano-1 para indivíduos ocupacionalmente expostos.
The present work describes steps undertaken for the viability of new radiometric methodologies of the portable systems calibration used in the LABIDRO (Isotopes and Hydrochemistry Laboratory) of DPM (Petrology and Metalogeny Department) of IGCE (Geoscience and Exact Sciences Institute) at UNESP, Rio Claro Campus. Among the topics covered are the determination of detection times with greater accuracy, dosimetric calibration curves and dosimetry data acquisition in the air, for indoor and outdoor environments, through gamma spectrometer detectors. Geostatistical models generated from the conversion of data, to the sites analyzed in the departments of Geology Course at UNESP, in effective dose, have shown that although there are some values set above those recommended by ICRP and by legal norm CNEN-NN-3.01 of 1 mSv.year-1, there is no need to intervene in places where it occurred (Heinz Ebert Museum; Deposit of rocks and minerals - DPM), Since these sites are of short period of visit time and, in addition, are below the recommended limit of 20 mSv.year-1 for occupationally exposed individuals.
CAPES: 00.889.834/0001-08
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Balbino, Daniela Pereira. "O método dos parâmetros fundamentais em FRX e sua implementação efetiva." Universidade Federal de Sergipe, 2014. https://ri.ufs.br/handle/riufs/5380.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPESThe materials characterization techniques, especially the X-ray diffratometry (XRD) and the X-ray fluorescence spectroscopy (XRF) has been well developed since the x-ray discovery at the end of XIX century, the x-ray diffraction phenomena by crystals at the beginning of XX century. Despite the two techniques derived from a common scenario, the quantitative X-ray fluorescence spectroscopy has been an advance more slowly, when compared to X-ray diffractometry. This lead the XRF to bee more knowledge by quick and fast qualitative analyses. By other side XRD technique has the quantitative principles established since the 50 decade of the last century. Around the 80 decade a increase of the interest about the quantitative procedures was did due to the possibility of the numerical treatment of the Sherman equations. This lead to a minimize the need of a individual standards in XRF. Many algorithms was described in the scientific literature about the XRF and it was the main interest in these mastering degree development, because in later times was development an first software by the group with goal the understand so well the quantification methodologies involving in chemical analysis by XRF. This work has as the main subject the validation of a new version of the software IILXRF2012, which was subject of a later mastering in the research group.
As técnicas de caracterização de materiais, em especial a difratometria de raios X (DRX) e a espectroscopia de fluorescência de raios X (FRX) tem se desenvolvido a passos largos desde a descoberta dos raios X no final do século XIX e da observação do fenômeno de difração dos raios X por cristais no início do século XX. Embora essas duas técnicas, de certa forma, sejam derivadas de um cenário comum, a interação dos raios X com a matéria, a espectroscopia de fluorescência de raios X teve um avanço, do ponto de vista quantitativo mais lento do que a difratometria de raios X. Isso levou a técnica de FRX a ser mais conhecida pela realização rápida de análises qualitativas do que quantitativas enquanto que técnica de DRX desde o final da década de 50 do último século já possuía os fundamentos do refinamento de estruturas, algo que atualmente nem é mais novidade. Todavia em meados da década de 80 do século passado houve um significativo aumento do interesse na técnica de FRX devido a possibilidade de tratamento numérico das equações de Sherman desenvolvidas em meados da década de 50 que forneciam o caminho matemático para a determinação quantitativa elemental através de uma análise teórica, praticamente eliminando a necessidade de padronização. Em razão disso diversos algoritmos foram sendo desenvolvidos ao longo das últimas décadas e no intuito de uma compreensão de como esse tipo de medida é possível, uma dissertação de mestrado foi defendida pela nossa equipe procurando explorar os conceitos envolvidos nessas análises. Em razão dos resultados serem promissores decidiu-se pela continuidade desse trabalho procurando-se uma implementação efetiva da metodologia desenvolvida para análise quantitativa de FRX via resolução numérica das equações de Sherman. Para tanto escolheu-se um conjunto de materiais para testes no intuito de validar uma nova versão do software IILXRF2012, cuja primeira versão foi objeto do desenvolvimento do trabalho de dissertação anterior.
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Chakraborty, Arup Ratan. "Differential Expression of Integrin α3β1 and α6β4 Molecules on a Panel of Rat Esophageal Cell Lines." Bowling Green State University / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1131345357.
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Rachwal, James D. "X-ray diffraction applications in thin films and (100) silicon substrate stress analysis." Scholar Commons, 2010. http://scholarcommons.usf.edu/etd/1745.
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Silicon is used as a substrate for X-ray mirrors for correct imaging. The substrate needs to be mechanically bent to produce a certain curvature in order to condition and focus the X-ray beam. The X-rays impinge a mirror at very shallow angles, in order to reduce the amount of intensity loss in the diffraction process. The X-ray mirrors need to be bent to an extremely precise profile, and even small distortions from this profile can reduce the effectiveness of the X-ray mirrors. The X-rays that impinge on the mirror also produce large amounts of heat that can change the temperature of the substrate, resulting in its thermal expansion and distortion. By measuring the distortions in-situ caused by these temperature changes it may be possible to correct for these errors. A four-point bending fixture was designed for in-situ X-ray bending experiments in order to measure the distortions to the (100) silicon sample caused by the bending setup.
By being able to measure the distortion caused by the setup, in like manner it would be possible to measure distortion caused by thermal expansion. Several alignments were needed in order to obtain accurate results, including adding copper powder on top of the sample. The copper powder that was added is not under stress, and therefore will not shift its reflection peak when the sample is under bending stress, thus serving as a reference in order to make corrections. The strain results were then compared to values calculated from mechanical deflections from bending. Despite the efforts to control accuracy, a significant variation appeared in the values when the top surface was in compression. As an alternative an IONIC stress-gauge was used to measure the deflections of the sample rather than calculate them.
Another alternative was to calculate the deflection of the substrate by first determining the stress in the layer deposited onto the mirror's substrate by using sin²psi technique, then using Stoney's equation to determine the change in curvature of the substrate, with the stress in the layer being known. Several tests were performed to demonstrate the ability to measure these deflections.
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Mountford, Lorna Catherine. "High intensity laser interactions with sub-micron droplets." Thesis, Imperial College London, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.369219.
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Stever, Samantha Lynn. "Characterisation and modelling of the interaction between sub-Kelvin bolometric detectors and cosmic rays." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS009/document.
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Nous avons étudié l'effet des rayons cosmiques dans les détecteurs en utilisant un bolomètre de germanium composite NTD à basse température, et une source de particules alpha comme source générique d'impulsions. Nous avons caractérisé ce bolomètre en constatant que la forme de son impulsion était due à la combinaison de sa réponse impulsionnelle (la somme de deux exponentielles doubles), et des effets liés à la position découlant de la thermalisation des phonons balistiques en phonons thermiques dans son absorbeur. Nous avons établi un schéma décrivant la forme de l'impulsion dans ce bolomètre en comparant une impulsion mathématique générique à une seconde description basée sur la physique thermique. Nous constatons que la thermalisation des phonons balistiques, suivie de la diffusion thermique, jouent un rôle important dans la forme de l'impulsion, en parallèle avec le couplage électrothermique et les effets électriques dépendant de la température. Nous avons modélisé les impulsions en observant que leur comportement peut être reproduit en tenant compte de la réflexion de phonons balistiques sur le bord de l’absorbeur, avec un couplage thermique fort au capteur central du bolomètre. Compte tenu de ces résultats, nous étudions également les effets des rayons cosmiques sur l’instrument Athena X-Ray Integral Field Unit (X-IFU), en produisant des timelines simulées et en testant la hausse de la valeur moyenne de la température (RMS) sur la plaquette du détecteur. Nous montrons que le flux thermique attendu des rayons cosmiques est au même ordre de grandeur que le maximum autorisé ΔTRMS ce qui constitue une menace sur le budget de la résolution énergétique de l'instrumentWe have studied the effect of cosmic rays in detectors using a composite NTD germanium bolometer at low temperatures and an alpha particle source as a generic source of pulses. We have characterised this bolometer, finding that its pulse shape is due to a combination of its impulse response function (the sum of two double exponentials), and position-dependent effects arising from thermalisation of ballistic phonons into thermal phonons in its absorber. We have derived a scheme for describing the pulse shape in this bolometer, comparing a generic mathematical pulse shape with a second description based on thermal physics. We find that ballistic phonon thermalisation, followed by thermal diffusion, play a significant role in the pulse shape, along with electro-thermal coupling and temperature-dependent electrical effects. We have modelled the pulses, finding that their behaviour can be reproduced accounting for ballistic phonon reflection off the absorber border, with a strong thermal coupling to the bolometer’s central sensor. With these findings, we also investigate the effects of cosmic rays on the Athena X-Ray Integral Field Unit (X-IFU), producing simulated timelines and testing the average RMS temperature increase on the detector wafer, showing that the expected cosmic ray thermal flux is within the same order of magnitudeas the maximum allowed ΔTRMS, posing a threat to the instrument’s energy resolution budget
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Fernàndez, Banqué Ferran. "New micro pattern gas detector for x-ray diffraction experiments in the sub-millisecond time scale." Doctoral thesis, Universitat Autònoma de Barcelona, 2007. http://hdl.handle.net/10803/3387.
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En instal·lacions de radiació sincrotró, es necessiten detectors amb una bona resolució espacial i un alt ritme de contes local per tal de dur a terme experiments de difracció de raigs x en l'escala temporal del mil·lisegon. Els detectors de gas de micro-fabricació (MPGD) poden satisfer aquests requeriments gràcies a l'alta densitat d'elèctrodes que presenten. No obstant aquest tipus de detectors presenten dos grans problemes: descàrregues elèctriques destructives i un deteriorament continu durant el seu us continuat.En aquest treball presentem una nova estructura de MPGD: el Micro Reading Mesh Chamber (MRMC). És un MPGD amb un estadi d'amplificació. El detector està dividit en dues regions: la regió de deriva i la regió de multiplicació. Aquestes estan separades per una malla formada per elèctrodes de lectura. El pla de l'ànode té una capa de material resistiu a la seva superfície.
El disseny del MRMC redueix els problemes que els actuals MPGD presenten. Entre d'altres avantatges, el posicionament dels elèctrodes de lectura a la malla incrementa la sensibilitat dels càtodes a la senyal. Això permet una reducció de la intensitat del camp elèctric de multiplicació. En conseqüència, la càrrega del detector i la probabilitat de descàrregues destructives es redueix.
S'han realitzat diverses simulacions per tal d'avaluar i optimitzar el rendiment del detector. Degut al gran nombre de paràmetres que poden ser escollits i del gran nombre de característiques que en depenen, s'ha realitzat un treball de simulació i optimització global. En primer lloc, s'ha dissenyat un programa basat en tècniques Monte-Carlo per tal de simular el procés de detecció i poder així avaluar la resolució espacial en funció dels diferents paràmetres del detector. En segon lloc, s'han realitzat una sèrie de simulacions que involucren la simulació del moviment en tres dimensions de les càrregues i la seva multiplicació dins l'estructura de detecció. Aquests estudis inclouen la estimació de la transparència de la malla, l'estudi de les línies i els temps de deriva dels ions, i la simulació del procés d'allau. Part d'aquestes simulacions han estat verificades experimentalment. Finalment, les capacitancies entre els elèctrodes i l'ànode i entre elèctrodes s'ha simulat per tal d'avaluar el soroll electrònic i els efectes de "crosstalk".
S'ha construït i provat un prototip. Els tests realitzats mostren una bona concordança amb les simulacions del guany. Així doncs, queda demostrat que el MRMC pot arribar a ritmes de contatge local >1.25·105Hz/mm2. No obstant, s'observen guspires en el detector degut a la presència de material dielèctric a la superfície dels càtodes. Degut a la superfície resistiva i la robustesa de l'estructura, el detector ha resistit les descàrregues sense rebre ningun dany. En conseqüència, per tal de que el MRMC esdevingui un detector útil, s'han de millorar tant el procediment de construcció, com les tècniques de neteja.
En conclusió, es necessita més treball experimental per tal d'obtenir un detector lliure de descàrregues completament funcional pel qual les simulacions prediuen un alt ritme de comptes local (>1.25·105Hz/mm2) i una bona resolució espacial (>250?m).
At synchrotron radiation facilities, detectors with high spatial resolution and high local count rate are needed in order to perform x-ray diffraction/scattering on time resolved experiments on the sub-millisecond time scale. Micro Pattern Gas Detectors (MPGD) could provide good spatial resolutions and high count rate thanks to their small cells of amplification region. Despite their promising performance, two major problems have arisen: rare but damaging discharges and, slow but continuous deterioration (aging) during sustained irradiation
Here we present a new MPGD structure: the Micro Reading Mesh Chamber (MRMC). It is a one stage amplification MPGD. It is divided in two regions: the drift/conversion region and the multiplication region. They are separated by a mesh formed by thick (25?m) pick-up strips. The anode plane has a resistive layer on it.
The design of the MRMC reduces the problems that the present MPGD show. Among other advantages, placing the pick-up strips at the mesh, instead of at another readout plane, increases the signal sensitivity of the cathodes. It allows a decrease of the gain through a reduction of the multiplication field. Therefore, it reduces the charging up and the probability of voltage and rate-induced dielectric breakdown.
Different simulations have been carried out to evaluate and optimize the performance of the detector. Due to the large number of detector parameters that can be chosen, and the features that depend on them, a global simulation was done. Firstly, a Monte-Carlo based program that reproduces the detection in the chamber has been developed in order to simulate the spatial resolution as a function of different parameters of the detector. Secondly, a set of studies that involve the simulation of the three dimensional movement of the charges in the chamber and its multiplication have been carried out. These models include the estimation of the mesh transparency, the study of the ion drift paths and times, and the simulation of the avalanche process. Part of these simulations has been cross-checked experimentally. Finally, the capacitances between the strips and the anode, and between strips has been simulated in order to evaluate the electronic noise and the crosstalk effects.
After the simulation work, a prototype was built and tested. The tests show good agreement between the simulated and the experimental gain. This agreement on the space charge calculations demonstrates that the MRMC can deliver local count rates >1.25·105Hz/mm2. Moreover, due to the resistive layer and the strength of the structure, the detector survived without noticeable damage. However, the detector suffers from discharges because of dielectric deposits on the cathode surface. Therefore, to turn this device into a detector for routine use, it will be necessary to both improve the construction process of the mesh structure and to develop an exhaustive cleaning procedure.
In conclusion, more experimental work is necessary to obtain a spark protected functional detector for which the simulations predict a high local count rate (>1.25·105Hz/mm2) and a good spatial resolution).
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Svensson, Anna-Carin. "In the service of the European Union : the role of the presidency in negotiating the Amsterdam treaty 1995 - 97 /." Stockholm : Elanders Gotab, 2000. http://www.gbv.de/dms/sub-hamburg/314397922.pdf.
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Tsirikoglou, Apostolia. "Efficient Simulation and Rendering of Sub-surface Scattering." Thesis, Linköpings universitet, Medie- och Informationsteknik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-102754.
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In this thesis, a new improved V-Ray subsurface scattering shader based on the improved diffusion theory is proposed. The new shader supports the better dipole and the quantized diffusion reflectance model for layered translucent materials. These new implemented models build on previous diffusion BSSRDFs and in the case of quantized diffusion uses an extended source function for the material layer. One of the main contributions and significant improvement over V-Ray’s existing subsurface scattering shader is the front and back subsurface scattering separation. This was achieved by dividing the illumination map that is used to calculate each shading’s point color, in two parts: the front part that comes of front lighting and the back one that comes of back lighting. Thus, the subsurface scattering layer can be divided in its consisting parts and each of them can be controlled, weighted and used independently. Finally, the project’s outcome is a new V-Ray material that provides all the above improvements in an intuitive, practical and efficient shader with several intuitive algorithm and light map controls, where artists can create subsurface scattering effects through three subsurface scattering layers.
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RANIERI, IZILDA M. "Crescimento de cristais de LiY sub(1-x) TR sub(x) F sub(4):Nd (TR=Lu ou Gd) para aplicacoes opticas." reponame:Repositório Institucional do IPEN, 2001. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10935.
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Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
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O'Brien, J. W. "The sub-division of alpha-adrenoceptors in vascular smooth muscle." Thesis, University of Glasgow, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.381481.
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Liu, Chih-Yuan. "Probing the abundance of sub-kilometer trans-neptunian objects using stellar occultations in X-ray and optical observations." Observatoire de Paris (1667-....), 2014. http://www.theses.fr/2014OBSP0247.
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Les objets transneptuniens (OTNs) sont les témoins de la formation des planètes durant la période dynamique et collisionnelle de notre système solaire. Les caractéristiques de cette population d’OTNs sub-kilométriques peuvent apporter des indices importants sur l’origine des planètes. Cependant, leur connaissance est loin d’être suffisante, en particulier pour les très petits objets, ceci à cause du peu de détections. Actuellement, seuls les OTNs plus grands que 25 km peuvent être directement observés. Pour les OTNs ne pouvant être observés directement, rechercher des évènements d’occultations stellaires fortuites est une méthode possible. Plusieurs recherches fortuites ont été menées, mais jusqu’à présent il n’y a que deux détections possibles, obtenues à partir des données d’archives du Télescope Spatial hubble par Schlichting et al en 2009 et 2012. Mon travail de thèse consiste à rechercher plus d’OTNs de taille sub-kilométrique en utilisant la méthode des occultations fortuites. Cette recherche est divisée en deux parties majeures : dans les longueurs d’onde X et visibles. Les observations X proviennent toutes du satellite RXTE (Rossi X-rays Timing Explorer), et les observations visibles proviennent du satellite COROT et de l’instrument MIOSOTYS installé sur deux télescopes au sol en France et en Espagne. A partir du 334-ks de données obtenues avec le RXTE/PCA, aucun évènement d’occultation par un OTN n’a été trouvé. La seule chute du signal suspecte et non instrumentale a pu être écartée grâce à une modélisation non fructueuse du signal par un profil diffractant. Nous avons analysé l’influence de la taille de l’OTN sur l’efficacité de détection afin de mieux définir l’intervalle de taille que nous sondions avec notre méthode. Nous avons pu ainsi donner une limite supérieure sur la distribution de taille des OTNs dans l’intervalle 30-300m. Nous proposons aussi une liste de sources X adéquates à observer avec de plus grands détecteurs. Le temps total d’observation extrait des données COROT est d’environ 144408,34 heures-étoiles, avec un S/B supérieur à 1000 calculé sur des intervalles de 30 secondes. 13 évènements possibles d’occultation (EPOs) ont été trouvés à partir de la méthode des fluctuations. L’instrument MIOSOTYS a été installé en tant qu’instrument visiteur sur le télescope de 1,93 m à l’Observatoire de haute-Provence (OHP) en France depuis février 2010, et sur le télescope de 1,23 m de Calar Alto (CAHA) en Espagne depuis novembre 2012. Jusqu’en juillet 2014, le projet MIOSOTYS a mené à bien 19 campagnes d’observation. Le temps total d’exposition est d’environ 3,5\times 10^7 s, ce qui représente environ 9840 heures d’étoiles sur 85 nuits ! Pour MIOSOTYS, nous avons développé une stratégie d’observation optimisée pour la recherche des OTNs. Nous avons aussi développé dans ce projet un nouvel algorithme de recherche d’évènements par la méthode des fluctuations. Les objets transneptuniens (OTNs) sont les témoins de la formation des planètes durant la période dynamique et collisionnelle de notre système solaire. Les caractéristiques de cette population d’OTNs sub-kilométriques peuvent apporter des indices importants sur l’origine des planètes. Cependant, leur connaissance est loin d’être suffisante, en particulier pour les très petits objets, ceci à cause du peu de détections. Actuellement, seuls les OTNs plus grands que 25 km peuvent être directement observés. Pour les OTNs ne pouvant être observés directement, rechercher des évènements d’occultations stellaires fortuites est une méthode possible. Plusieurs recherches fortuites ont été menées, mais jusqu’à présent il n’y a que deux détections possibles, obtenues à partir des données d’archives du Télescope Spatial hubble par Schlichting et al en 2009 et 2012. Mon travail de thèse consiste à rechercher plus d’OTNs de taille sub-kilométrique en utilisant la méthode des occultations fortuites. Cette recherche est divisée en deux parties majeures : dans les longueurs d’onde X et visibles. Les observations X proviennent toutes du satellite RXTE (Rossi X-rays Timing Explorer), et les observations visibles proviennent du satellite COROT et de l’instrument MIOSOTYS installé sur deux télescopes au sol en France et en Espagne. A partir du 334-ks de données obtenues avec le RXTE/PCA, aucun évènement d’occultation par un OTN n’a été trouvé. La seule chute du signal suspecte et non instrumentale a pu être écartée grâce à une modélisation non fructueuse du signal par un profil diffractant. Nous avons analysé l’influence de la taille de l’OTN sur l’efficacité de détection afin de mieux définir l’intervalle de taille que nous sondions avec notre méthode. Nous avons pu ainsi donner une limite supérieure sur la distribution de taille des OTNs dans l’intervalle 30-300m. Nous proposons aussi une liste de sources X adéquates à observer avec de plus grands détecteurs. Le temps total d’observation extrait des données COROT est d’environ 144408,34 heures-étoiles, avec un S/B supérieur à 1000 calculé sur des intervalles de 30 secondes. 13 évènements possibles d’occultation (EPOs) ont été trouvés à partir de la méthode des fluctuations. L’instrument MIOSOTYS a été installé en tant qu’instrument visiteur sur le télescope de 1,93 m à l’Observatoire de haute-Provence (OHP) en France depuis février 2010, et sur le télescope de 1,23 m de Calar Alto (CAHA) en Espagne depuis novembre 2012. Jusqu’en juillet 2014, le projet MIOSOTYS a mené à bien 19 campagnes d’observation. Le temps total d’exposition est d’environ 3,5\times 10^7 s, ce qui représente environ 9840 heures d’étoiles sur 85 nuits ! Pour MIOSOTYS, nous avons développé une stratégie d’observation optimisée pour la recherche des OTNs. Nous avons aussi développé dans ce projet un nouvel algorithme de recherche d’évènements par la méthode des fluctuationsTrans-Neptunian objects (TNOs) are the witnesses of the formation of the planets during the dynamical and collisional period of our solar system. The population characteristics of sub-kilometer TNOs may carry some important clues for the origin of the planets. However, the knowledge of them is far from enough, particularly for those sub-kilometer ones, due to very fex directions. Now adays only TNOs larger than about 25 km can be directly observed. For the TNOs not able to be directly observed, searching for serendipitous stellar occultation events is a possible method. Several serendipitous searches were proceeded, but so far there are only two possible detections from archival data of Hubble Space Telescope by Schlichting et al. In 2009 and 2012. My thesis work is going to search for more sub-kilometer sized TNOs by applying the serendipitous occultation method. The search is divided into two major parts : in X-rays and in optical bands. The X-rays observations are all from the RXTE satellie, and the optical observations are from COROT satellite ans MIOSOTYS instrument mounted on two ground-based telescopes in France and Spain. From 334-ks, no definite TNO occultation events were found. The only suspicious non-instrumental flux-drop event was not considered to be resulted from the small TNO occultation after analyzing it with the fittings of the diffraction patterns. Then we investigate the detection efficiency dependence on the TNO size to better define the sensible size range of our approach, and suggested upper limits to the TNO size distribution in the size range from 30 to 300 m. A list of X-ray sources suitable for future larger facilities to observe is proposed. The total observation time employed in our COROT work is about 144408. 34 star-hours with SNR larger than 1000 computed on 30-second intervals. 13 Possible Occultation Events (POEs) were found from the deviation method. The MIOSOTYS instrument has been mounted as a visitor instrument on the 1. 93 m telescope at Observatoire de Haute-Provence (OHP) in France since february 2010, and on the 1. 23 m telescope at Calar Alto Observatory (CAHA) in Spain since november 2012. By july 2014, MIOSOTYS project has successfukky carried out 19 observational runs. The total exposure time before screening is about 3. 5 \times 10^7 sec, which is about 9840 star hours, from 85 nights. For MIOSOTYS, we have developed an optimized observing strategy to search for TNOs. We have also developed in this project a new search algorithm of events by the method of fluctuations
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Rodrigues, Michelle Santos. "Avaliação de cinzas de palha de cana-de-açúcar e sua utilização como adição mineral em matrizes cimentícias." [s.n.], 2012. http://repositorio.unicamp.br/jspui/handle/REPOSIP/256818.
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Orientadores: Antonio Ludovico Beraldo, Holmer Savastano JúniorTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agrícola
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Resumo: Neste trabalho produziram-se cinzas de palha de cana-de-açúcar por queima controlada para avaliar a sua aplicação como adição mineral em matrizes cimentícias. As palhas foram submetidas a quatro diferentes temperaturas de queimas: 600 °C, 700 °C, 800 °C e 900 °C, e as cinzas foram denominadas CPCA600, CPCA700, CPCA800 e CPCA900, respectivamente. Após a queima cada cinza passou por um processo de moagem e foi submetida a análises de fluorescência de raios X, difração de raios X, microscopia eletrônica de varredura, granulometria a laser, massa específica real por picnometria a gás e superfície específica por B.E.T (Brunauer-Emmett-Teller). A reatividade das cinzas foi avaliada por meio de medições de condutividade elétrica em soluções insaturadas de Ca(OH)2/cinzas. Foram analisadas pastas com cimento Portland ou hidróxido de cálcio em função da idade de cura úmida (7, 28, 63 e 91 dias) por meio das técnicas de termogravimetria, compressão simples, compressão diametral, absorção de água, porosidade aparente, massa específica aparente, porosimetria por intrusão de mercúrio, microscopia eletrônica de varredura, calorimetria e difração de raios X de alta resolução, realizada no Laboratório Nacional de Luz Síncrotron. As cinzas CPCA600 e CPCA700 foram consideradas mais reativas e foram aplicadas em compósitos de fibrocimento. As caracterizações das cinzas mostraram que a CPCA600 e a CPCA700 contêm composição química de material pozolânico, partículas com elevada nano e microporosidade e elevadas áreas de superfície específica, assim como foi observado um halo de amorficidade nos difratogramas de ambas as cinzas. O ensaio de condutividade elétrica no sistema hidróxido de cálcio/cinzas mostrou elevada reatividade dessas cinzas. Na avaliação das pastas, as cinzas CPCA600 e CPCA700 apresentaram maior consumo de hidróxido de cálcio, maior resistência à compressão simples e menor volume de poros. As caracterizações físicas (absorção de água, porosidade aparente e massa específica aparente) e mecânicas (módulo de ruptura, energia específica, módulo de elasticidade e limite de proporcionalidade) dos compósitos mostrou que aqueles produzidos com a CPCA700 apresentaram características físicas e mecânicas similares àquelas do controle, o que viabiliza a substituição parcial do cimento Portland pela mesma
Abstract: This research work produced sugarcane straw ashes by controlled burning and evaluates its application as mineral admixture in cementitious matrices. Straws were subjected to four different burning temperatures. Straws were dried and burned at 600 °C, 700 °C, 800 °C and 900 °C that were named SCSA600, SCSA700, SCSA800 and SCSA900, respectively. After firing the material passed through a milling process and it was subjected to analysis of X ray fluorescence, X ray diffraction, scanning electron microscopy (SEM), particle size laser, real density and specific surface area by B.E.T (Brunauer-Emmett-Teller). The reactivity evaluation of the ashes was performed by measuring the electrical conductivity of insaturated solutions of Ca(OH)2/ash. Pastes with Portland cement or calcium hydroxide were evaluated according to the curing hydration age (7, 28, 63 and 91 days) by means of thermogravimetry, compressive strength, splitting test, water absorption, apparent porosity and bulk density, mercury intrusion porosimetry, scanning electron microscopy, calorimetry and high-resolution X-ray diffraction, at the National Laboratory of Synchrotron Light. The ashes SCSA600 and SCSA700 were considered more reactive and have been applied in cement composite. The characterizations show that SCSA600 and SCSA700 ashes contain chemical composition of pozzolanic material, and nano particles with high microporosity, and consequently, with high specific surface areas, as has been observed halo amorphicity in both diffractograms ashes. Electrical conductivity obtained at the system calcium hydroxide/ashes showed high reactivity for these ashes. In the pastes evaluation, the ashes SCSA600 and SCSA700 showed higher consumption of calcium hydroxide, higher compressive strength and reduced volume of pores. The physical characterizations (water absorption, apparent porosity and bulk density) and mechanical (modulus of rupture, specific energy, elastic modulus and proportionality limit) of the composites showed that those produced with the ash SCSA700 were similar to the control ones, which enables the partial replacement of Portland cement by this kind of ash
Doutorado
Construções Rurais
Doutora em Engenharia Agrícola
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Gharehbaghi, Ali. "Precipitation Study in a High Temperature Austenitic Stainless Steel using Low Voltage Energy Dispersive X-ray Spectroscopy." Thesis, KTH, Materialens processteknologi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-103492.
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Precipitation of second phase particles is a key factor dominating the mechanical properties of high temperature alloys. In order to control and optimize the precipitation effect it is of great importance to study the role of alloying elements in the formation and stability of precipitates. As a favored family of corrosion and creep resistant austenitic stainless steels the 20Cr-25Ni alloy was modified by addition of copper, molybdenum, nitrogen, niobium and vanadium. A set of alloys with similar matrix but varying contents of niobium, vanadium and nitrogen were prepared. Sample preparation process included melting, hot forging, solution annealing and finally aging for 500 h at 700, 800 and 850 ºC.Light optical and scanning electron microscopy revealed micron-scale precipitates on grain and twin boundaries as well as sub-micron intragranular precipitates in all samples. Characterization of precipitates was carried out by means of energy dispersive X-ray spectroscopy (EDS). Among micron-scale precipitates M23C6 carbide was the dominant phase at 700 ºC aging temperature; whereas silicon-rich eta phase (M5SiC) was the main precipitate in samples aged at 800 and 850 ºC. A few sigma phase particles were found in one of the niobium containing samples aged at 700 and 800 ºC. Sub-micron intragranular precipitates were analyzed using low voltage EDS. The spatial resolution of EDS microanalysis at 5 kV accelerating voltage was estimated as almost 100 nm which was at least eight times better than that using the ordinary 20 kV voltage. Also, low voltage EDS revealed the presence of light elements (carbon, nitrogen and boron) in the composition of sub-micron particles thanks to the less matrix effect in absorption of low energy X-rays of light elements. In samples aged at 700 ºC niobium-rich and vanadium-rich carbonitrides were found as the dominant precipitates; whereas they contained much less carbon in samples aged at 800 ºC and mostly became carbon-free nitrides with well-defined cuboidal shapes at 850 ºC aging temperature. This showed that niobium/vanadium-rich nitride phases are stable precipitates at aging temperatures above 700 ºC.The drawbacks of low voltage EDS were indicated as high detection limit (no detection of low- content elements), poor accuracy of quantitative analysis and high sensitivity to surface contamination. Some possible ways to improve the accuracy of low voltage EDS, e.g. longer acquisition time were examined and some other suggestions are proposed for future works.
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Garcia, Chaparro Bayron. "Reactive compatibilization of poly(styrene-ran-acrylonitrile)(SAN) / poly(ethylene) blends using thiol and epoxy functional SAN." Thesis, McGill University, 2014. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=123284.
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Well-defined styrene/acrylonitrile (SAN) statistical copolymers with thiol functionality were synthesized for use as a barrier material when melt-blended with epoxy grafted poly(ethylene) (E-PE). SAN was synthesized via reversible addition fragmentation chain transfer polymerization (RAFT) in dimethylformamide (DMF) solution, using dibenzyl trithiocarbonate (DBTC) as chain transfer agent (CTA) and 2, 2'-azobis(isobutyronitrile) (AIBN) as initiator. Typically, SAN copolymers exhibited relatively narrow molecular weight distribution with number average molecular weights (M ̅_n) of 31.4-37.6 kg•mol-1 (M ̅_w/M ̅_n (PDI) = 1.3-1.4) and a sufficiently high acrylonitrile (AN) incorporation for barrier properties (35-40 mol.%). The trithiocarbonate-containing SAN was reacted post-polymerization via an aminolysis reaction to yield thiol end-functional SAN (SH-SAN). SH-SAN was melt-blended with both E-PE and non-functional poly(ethylene) (PE) in a miniature twin screw extruder at 20 wt.% loading at 180ºC. The SAN dispersed phase morphology of the blend was characterized using scanning electron microscopy and consisted of droplets with volume to surface average diameter (〈D〉sv) of 1.3 μm for the reactive E-PE/SH-SAN (80/20 wt.%) blend and 3.8 μm for the non-reactive PE/SH-SAN. For the reactive blend, the dispersed SAN droplets coarsened to 〈D〉sv = 2.5 μm, however the droplets remained smaller than the droplets from the SH-SAN/PE blend (〈D〉sv = 3.9 μm). The dispersed SAN domains were reoriented using a channel die to impart elongated domains which would be desirable for barrier materials.Epoxy grafted SAN (E-SAN) was also synthesized by the terpolymerization of AN, styrene (ST), and glycidyl methacrylate (GMA) via RAFT in DMF solution, using DBTC as CTA and AIBN as initiator. Three E-SAN terpolymers were synthesized at GMA loadings of 5, 10 and 20 mol.% with M ̅_ns ranging from 34.8-38.3 kg•mol-1, PDI =1.4-1.5 and final AN compositions from 29-40 mol.%.Des copolymères de styrène-acrylonitrile (SAN) bien définis avec des fonctionnalités de thiol ont été synthétisés pour être utilisés comme matériau format une barrière lorsque mélangé au dessus de leur point fusion avec du poly(éthylène) greffé d'époxy (E-PE). Le SAN a été synthétisé via une polymérisation radicalaire contrôlée par transfert de chaîne réversible par addition-fragmentation (RAFT) dans une solution de diméthylformamide (DMF), en utilisant du dibenzyle trithiocarbonate (DBTC) comme agent de transfert de chaîne (CTA) et 2,2'-azo-bis(isobutyronitrile (AIBN) comme initiateur. Typiquement, les copolymères de type SAN présentent une distribution de masse moléculaire relativement étroite avec une moyenne en nombre de (M ̅_n) de 31.4-37.6 kg•mol-1 (M ̅_w/M ̅_n (PDI) = 1.3-1.4) et suffisamment élevé acrylonitrile (AN) constitution pour les applications de barrières (35-40 %.mol). Une réaction aminolyse induite post-polymérisation SAN avec trithiocarbonate a résulté en SAN avec des groupes thiol fonctionnels aux extrémités (SH-SAN). SH-SAN a été mélangé au dessus de son point de fusion avec à la fois E-PE et du poly(éthylène) (PE) non fonctionnel dans une extrudeuse miniature à double vis (20% m/m à 180ºC). La morphologie de phase dispersée (SAN) du mélange a été caractérisé en utilisant un microscope électronique à balayage, donnant des gouttelettes avec un diamètre moyen (ratio volume à surface) (〈D〉sv) de 1.3 um pour le mélange réactif E-PE/SH-SAN (80/20% m/m) et 3.8 um pour non réactif PE/SH-SAN. Pour le mélange réactif, le diamètre des gouttelettes de SAN dispersées a augmenté à 〈D〉sv = 2.5um, en demeurant toutefois inférieur à celui des gouttelettes du mélange SH-SAN/PE (〈D〉sv = 3.9 μm). Les gouttelettes de SAN ont été réorientées en utilisant une matrice de manière à leur donner une forme allongée, désirable pour des matériaux de barrière.Le SAN greffé d'époxy (E-SAN) a été synthétisé par terpolymérisation de AN, styrène (ST) et méthacrylate de glycidyle (GMA) via RAFT dans une solution de DMF, en utilisant DBTC comme CTA et AIBN comme initiateur. Trois terpolymères de E-SAN étaient synthétisé à GMA compositions de 5,10 en 20 mol.% avec M ̅_ns allant de 34.8-38.3 kg•mol-1, PDI = 1.4-1.5 et une composition finale de AN de 29-40 %.mol.
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Oliveira, Otávio Riani de. "Determinação experimental dos perfis de espalhamento de tecidos mamários (normais e alterados) e sua potencialidade como ferramenta de diagnóstico." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/59/59135/tde-20042010-101014/.
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A distribuição angular de fótons espalhados (perfil de espalhamento) pode fornecer informações sobre as estruturas que compõe um tecido biológico, permitindo, a partir da análise desta, identificar a presença de anormalidades no tecido. A proposta deste trabalho foi desenvolver um procedimento experimental de medidas do perfil de espalhamento de tecidos mamários normais e alterados e, posteriormente, correlacionar as informações contidas neste com informações histopatológicas do tecido. Os perfis de espalhamento foram medidos no intervalo de momento transferido entre 0,2<= ? <=6,2 nm-1, utilizando um difractômetro Siemens D-5005, com ânodo de cobre e operando no modo reflexão. As amostras de tecidos mamários, foram previamente classificadas como tecidos normais, fibroadenomas e carcinomas. As intensidades medidas foram corrigidas por atenuação, efeitos geométricos e pela variação angular do feixe incidente. A eficácia do procedimento experimental foi validada através do uso de dados de referência para amostras de água. Os resultados mostraram que o perfil de espalhamento é uma característica única de cada tipo de tecido, sendo sua forma relacionada à morfologia microscópica do tecido. Na região em que x<=0,35 nm-1, verificou-se estatisticamente que as informações contidas nos perfis de espalhamento permitem a diferenciação entre tecidos normais e alterados.Angular distribution of photons scattered by tissues (scattering profile) gives detailed information of structures within them and provides an alternative mean of distinguishing pathologies. The proposal of this work was to develop an experimental procedure to determine scattering profiles from breast tissues (normal and neoplastic) and to correlate the information contained in these profiles with histopathological information. The scattering profiles were measured in the interval of momentum transfer 0,2 ? ? ? 6,2 nm-1, using a powder diffractomer apparatus (Siemens D-5005), with copper anode and operation in reflection mode. The breast samples were previously histopathologically classified as normal tissues, fibroadenomes and carcinomas. The measured angular distribution was corrected by attenuation, geometric effect and the angular variation of the incident beam. The effectiveness of the experimental procedure was validated through the use of water reference data. The results shown that, scattering profile is unique impression of each type of tissue, being correlated with the microscopic morphological features. In the region where ? ? 0,35 nm-1, were statistically verified that the information contained in the scattering profiles allow the differentiation between normal and neoplastic breast tissues.
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Arguillère, Stéphane. "Le système de Klong-chen rab-'byams et son expression littéraire." Paris 4, 2002. http://www.theses.fr/2001PA040227.
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Klong-chen-pa (1308-1364) fut l'un des principaux philosophes du Tibet. La thèse commence avec sa vie, suivie d'un inventaire des oeuvres authentiques, avec leur chronologie (132 p. ). L'essai qui lui fait suite (335 p. ) porte sur (1) l'absolu et la connaissance de l'absolu ; (2) l'omniscience des "Buddha" et sa dimension ontologique ; et (3) l'épiphanie du Fond et la procession du "samsâra" à partir du "Dharmadhatû". La quatrième partie s'achève sur une analyse de l'expression littéraire chez l'auteur, illustrée par une édition et traduction de huit chapitres du "CHos-dbyings mdzod" et quatre du "Lung gi gter mdzod" (160 p. ). Après l'index et la bibliographie, l'appendice (600 p. ) comporte : une table analytique et une notice de toutes les oeuvres, hormis les textes rituels et les poèmes ; un index des citations (1435 sources répertoriées) ; un catalogue du "rNying-ma-rgyud'bum" ; et un inventaire des deux sNying-tigKlong-chen rab-'byams (1308-1364) was one of the main philosophers of Tibet. The dissertation begins with his biography, followed by a catalogue of his genuine works, with the chronology of their composition (132 p. ). .