Dissertations / Theses on the topic 'High susceptibility'
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Wharton, Samuel James. "Susceptibility mapping in high field MRI." Thesis, University of Nottingham, 2011. http://eprints.nottingham.ac.uk/13074/.
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Phase images of the human brain acquired using gradient echo based Magnetic Resonance Imaging techniques show excellent contrast at 7T. This contrast is attributed to small variations in magnetic susceptibility that perturb the main magnetic field and thus yield a spatial variation of the NMR frequency. The work described in this thesis is primarily concerned with mapping the distribution of magnetic susceptibility within the human brain using these phase images. The main technical challenges of the project were first to extract accurate field maps based on phase data, and then to solve the ill-posed problem of inverting these field maps to reconstruct susceptibility (ϰ) maps. In initial work, simulations of field shifts based on known ϰ -distributions are compared to field maps acquired in vivo to highlight the non-local relationship between measured field offsets and the underlying susceptibility. These simulations were carried out using a recently derived Fourier method. The bulk of the thesis is then devoted to a detailed study of the process of inverting field maps generated from phase data using the Fourier relationship to yield quantitative 3D ϰ -maps. Unfortunately, the inversion problem is ill-posed and requires careful conditioning, either through rotation of the sample being imaged or through regularisation. A simple k-space threshold is introduced to condition the inversion and the preliminary results of applying this method to brain data from healthy subjects and patients with Parkinson's disease and multiple sclerosis are presented. The results suggest that susceptibility mapping is sensitive to iron deposition and could be a useful tool in investigating the progression of neurodegeneratived diseases. Iterative inversion algorithms, which deal with noise more robustly and allow more sophisticated filtering techniques to be employed, are then presented. These powerful regularisation methods are compared to previously described techniques, and are shown to yield high quality whole-brain ϰ -maps.
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Bulow, Barbara A. "HIV susceptibility among high-risk adolescents." Virtual Press, 1998. http://liblink.bsu.edu/uhtbin/catkey/1115725.
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The purpose of this study was to explore the association among risk behaviors, HIV/AIDS knowledge, and cognitive variables in high-risk adolescents. Subjects were 82 youth (50 males and 32 females) residing in a Midwest residential treatment facility for abused, neglected, or delinquent children and adolescents. The mean age of the adolescents was 14.6 years. Self-report measures of AIDS knowledge, invulnerability, self-efficacy, locus of control, sensation seeking, and risk involvement were administered in counterbalanced order. Data were analyzed using hierarchical multiple regression analysis to examine the relation between risk behaviors and scores on invulnerability, locus of control, self-efficacy, and sensation seeking measures once age and AIDS knowledge were controlled in the initial steps. Although age and knowledge of AIDS were related positively to the likelihood of behavioral risk taking, the combination of cognitive variables explained an additional 23% of the variance in risk behaviors and accounted for the largest proportion of shared variability. Therefore, adolescents' risk behaviors appeared to be determined by their cognitive beliefs to a greater degree than by their knowledge of the consequences of such behavior. The importance of cognitive factors in the apparent behavior choices that adolescents make suggests that educational prevention programs need to consider more than just the sharing of knowledge in addressing issues of risky behavior. Instead, the perceptions of adolescents toward sensation seeking and other cognitive characteristics also must be considered.Department of Educational Psychology
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Pathmanathan, N. "A.C. magnetic susceptibility of high-Tc superconductors." Thesis, University of Sussex, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.332772.
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El-Abbar, Abdallah Abdulwanis. "AC susceptibility studies of high-Tâ†c superconductors." Thesis, University of Nottingham, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.357929.
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Salim, Maan. "The AC magnetic susceptibility of high temperature superconductors." Thesis, University of Nottingham, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.270233.
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Figueroa-Gordon, Douglas J. "Hydrogen re-embrittlement susceptibility of ultra high strength steels." Thesis, Cranfield University, 2005. http://dspace.lib.cranfield.ac.uk/handle/1826/1433.
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300M ultra high strength steel has been widely used for over forty years as a structural material in aerospace applications where a high strength is required. These parts are generally protected from corrosion by electroplated cadmium sacrificial coatings. However, there are concerns over this coating material due to its high toxicity and alternative coatings including Zinc-14%Nickel and SermeTel®1140/962 have been considered. It is known that applying electrodeposited coatings causes atomic hydrogen to be absorbed by the steel substrate producing delayed failure by direct hydrogen embrittlement. Hydrogen is also absorbed when a sacrificial coating undergoes corrosion in service and this process is known as re-embrittlement. The effect of electroplated Zinc-14%Nickel and aluminium based SermeTel®1140/962 sacrificial coatings in causing hydrogen embrittlement and re-embrittlement of 300M steel have been compared to that of conventional electroplated cadmium. AerMet®100 ultra high strength steel has been also considered as alternative replacement for the conventional 300M. Hence, the hydrogen embrittlement and re-embrittlement susceptibilities of AerMet®100 were studied when coated with cadmium, Zinc-14%Nickel and SermeTel®1140/962. In addition, two alternative alloys GifloM2000 and CSS-42LTM were also taken into consideration and only the extent of hydrogen re-embrittlement was assessed when coated with cadmium and SermeTel®1140/962, respectively. Slow strain rate tests, SSRT, were carried out for plated, plated and baked as well as plated, baked and corroded tensile specimens. The time to failure values were compared using a Weibull distribution, statistical ttests and embrittlement indices. Differences in hydrogen susceptibility of the high strength steels considered might depend upon their intrinsic hydrogen transport characteristics. These properties were studied and compared in terms of hydrogen diffusivity and solubility.
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Truong, Trong-Kha. "Susceptibility effects in ultra-high field magnetic resonance imaging of the human brain." The Ohio State University, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=osu1093830567.
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Jönsson, Johan. "High precision Ac susceptibility : a probe to exchange bias, and flux creep in high-Tc materials /." Stockholm, 1998. http://www.lib.kth.se/abs98/jons1211.pdf.
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Parboosingh, Jillian S. "Biochemical and molecular analysis of monoamine oxidase in alcoholics, high risk subjects and low risk controls." Thesis, McGill University, 1991. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=61088.
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Alcoholism is a prevalent multifactorial disease with both genetic and environmental components. Monoamine oxidase (MAO) has been proposed as a susceptibility marker for familial alcoholism but consistent evidence of either specific MAO variants in alcoholics or allelic segregation in at-risk families has not been presented. Two structural genes on the X chromosome encode two forms of the enzyme, MAO-A and MAO-B. Kinetic constants for platelet MAO-B and restriction fragment length polymorphisms for MAO-A were determined in alcoholics with multigenerational family histories of alcoholism, high risk relatives of familial alcoholics and low risk controls with no family history of alcoholism. Mean elevated levels of MAO-B deamination were observed in alcoholics and high risk individuals. Alcoholic and high risk individuals did not differ from non-alcoholics with respect to MAO-B tryptamine affinity or MAO-A polymorphisms. Significant non-genetic factors influence MAO-B activity. MAO variants are unlikely to define a genetic predisposition to alcoholism.
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Sutton, Benjamin James. "Solidification Behavior and Hot Cracking Susceptibility of High Manganese Steel Weld Metals." The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1366302517.
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俞大風 and Tai-fung Yu. "An analysis of electrical transport and magnetic susceptibility properties of YBa2Cu3O7-[delta] and La2-xSrxCuO4 high Tcsuperconductors." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1997. http://hub.hku.hk/bib/B31238014.
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DI, MECO ANTONIO. "EFFECT OF GESTATIONAL HIGH FAT DIET ON ALZHEIMER’S DISEASE SUSCEPTIBILITY IN THE OFFSPRING." Diss., Temple University Libraries, 2019. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/598730.
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Biomedical SciencesPh.D.
Alzheimer’s disease (AD) is a progressive neurodegenerative disorder affecting over five million people in the US alone. Causes for the most common sporadic form of the disease are still obscure and no therapeutic approach is available to halt the progression of AD. Subjects whose mothers were affected by sporadic AD are three times more susceptible to develop the disease later in life compared to subject from sporadic AD fathers. However, the mechanisms of maternal transmissibility for sporadic AD are unknown. Lifestyle and nutrition are important risk factors for sporadic AD. Direct exposure to saturated fats and cholesterol is positively correlated to AD development later in life. We hypothesized that maternal exposure to high-fat diet throughout gestation would affect AD susceptibility in the offspring later in life. To tackle this biological question, triple transgenic (3xTg) dams carrying human APP (KM670/671NL), PSEN1 (M146V) and MAPT (P301L) mutations together with wild type da
Temple University--Theses
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Yu, Tai-fung. "An analysis of electrical transport and magnetic susceptibility properties of YBa2Cu3O7-[delta] and La2-xSrxCuO4 high Tc superconductors /." Hong Kong : University of Hong Kong, 1997. http://sunzi.lib.hku.hk/hkuto/record.jsp?B19036607.
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Labreche, Karim. "Genetic Susceptibility and Molecular Characterization of Glioma." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLS161/document.
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Les gliomes constituent les plus fréquentes des tumeurs malignes primaires du système nerveux central. Les liens qui existent entre ces tumeurs et un certain nombre de cancers rares héréditaires, comme les Neurofibromatoses I et II ou les syndromes de Turcot et de Li-Fraumeni, attestent d’une prédisposition génétique aux gliomes. L’observation d’un risque deux fois plus élevé de développer un gliome chez les parents de premier degré de patients atteints suggère aussi une possible prédisposition génétique dans les gliomes sporadiques. Par ailleurs, l’analyse à haut débit permet de préciser le profil somatique des gliomes et d’identifier des biomarqueurs pronostiques voire prédictifs et s’inscrire dans une démarche de traitement personnalisé du patient. Durant ma thèse, je me suis focalisé sur deux axes de recherches complémentaires; l’identification de gènes de susceptibilité et la découverte de nouveaux gènes fréquemment mutés dans les gliomes, afin de déterminer les voies de signalisation contribuant à la gliomagenèse. Dans leur ensemble, les résultats obtenus dans cette thèse apportent non seulement des informations importantes sur la nature de la prédisposition génétique aux gliomes mais également de son association spécifique pour les différents sous-types de tumeurs. La découverte d’un nouveau gène muté, offre la perspective à plus long terme d’un traitement personnalisé pour chaque patient sur la base du profil génétique de sa tumeurGliomas are the most common adult malignant primary tumour of the central nervous system. Thus far, no environmental exposures has been linked to risk except for ionizing radiation, which only accounts for a very small number of cases. Direct evidence for inherited predisposition to glioma is provided by a number of rare inherited cancer syndromes, such as Turcot's and Li–Fraumeni syndromes, and neurofibromatosis. Even collectively, these diseases however account for little of the twofold increased risk of glioma seen in first-degree relatives of glioma patients. My research was centred on two complementary research activities: Identifying susceptibility genes for glioma to delineate key biological pathways contributing to disease pathogenesis and to identify new recurrent mutated genes for glioma to provide for further insights into glial oncogenesis and suggesting targets for novel therapeutic strategies. Collectively the findings in this thesis provide increased insight into the nature of genetic predisposition to glioma and substantiate the often distinct associations between susceptibility variants and glioma molecular groups. In addition the discovery of a new mutated gene in glioma offers the potential to support drug development and advance precision medicine for this tumours
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Bracanovic, Darko. "Ac susceptibility and resistivity studies of YBaâ†2Cuâ†3Oâ†7â†-â†#delta# high-temperature superconductors." Thesis, University of Southampton, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302027.
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Flinkfeldt, Linnea. "High throughput pipeline for rapid antibiotic susceptibility testing and ID of bacteria from blood cultures." Thesis, Uppsala universitet, Institutionen för biologisk grundutbildning, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-388251.
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Rapid and accurate species identification and antibiotic susceptibility testing are of great importance for patients with sepsis and to stop over- and misuse of antibiotics contributing to antibiotic resistance. QuickMIC™ is a rapid antibiotic susceptibility testig system based on a microfluidic technology solution developed by Gradientech that measure MICs on bacteria from positive blood culture bottles. By combining QuickMIC™ with a rapid system for detection and identification, the time to detection, identification and antibiotic susceptibiolity testing could be shortened with days compared to pipelines used today which could mean the difference of life and death for patients. The T2Bacteria® panel and T2Dx® instrument developed by T2 biosystems is an FDA-cleared test for rapid detection and identification of bacteria from whole blood based on magnetic molecular resonance technology. The time to result of the T2Dx® instrument is 3-4 hours and the time to result for QuickMIC™ is 2-4 hours. In this project, the possibilities and benefits of such a pipeline have been studied by comparison to a pipeline typically used today. Time, accuracy and practical aspects have been investigated during the project and the results are promising for future further studies.
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Månsson, Daniel. "Intentional electromagnetic interference (IEMI) : Susceptibility investigations and classification of civilian systems and equipment." Doctoral thesis, Uppsala universitet, Elektricitetslära, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-9264.
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This PhD thesis addresses the threat posed to society by sources that can produce high power electromagnetic pulses (HEPM) and be used maliciously to disturb or damage electronic equipment. The vulnerability from intentional electromagnetic interference (IEMI) has increased in the recent decades due to the widespread dependence of the civil society on sensitive electronic systems and proliferation of radiation sources. As the characteristics of the disturbances associated with IEMI often have very high frequency content, the existing mitigation measures and protection components may not be adequate. It was seen that for ultra wideband (UWB) transients low voltage protection components may not work as intended, due to parasitic components that arises from the packaging of the device. The large spatial distribution of many civilian facilities and critical infra-structures (e.g., power generation, communications, train system, etc.) presents many unexpected ports for an attacker as the majority of the parts of these systems are not protected or secure. As the new European Rail Traffic Management System (ERTMS) will utilize wireless communication for communication and control of the trains the vulnerability from different radiating HPEM sources was investigated. Angles of incidence and frequencies that are a threat in a given situation are identified. Due to the possibility of unexpected ports, the propagation of differential mode ultra wideband transients in low voltage power networks, when injected into a power socket of a facility, was studied. The effects on the transient propagation from cable bends, switches and junctions were studied, both in a laboratory setup and in the network of a facility. Also, as modern electronic equipment and systems may not be tested for waveforms and disturbances other than standardized EMC tests, experiments on some common commercial-off-the-shelf (COTS) equipment were performed with non-standard test situation. It was seen that these could easily be disturbed or even permanently damaged. In addition, due to the inherent difficulties with IEMI, a new method for classifying facilities from IEMI is suggested. It is based on available terminology of accessibility (A), susceptibility (S) and consequence (C), but expands these and forms the so called IEMI/ASC-cube.
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Jahn, Peter Thomas [Verfasser], Guy D. [Akademischer Betreuer] Moore, and Jens [Akademischer Betreuer] Braun. "The Topological Susceptibility of QCD at High Temperatures / Peter Thomas Jahn ; Guy D. Moore, Jens Braun." Darmstadt : Universitäts- und Landesbibliothek Darmstadt, 2019. http://d-nb.info/1201820626/34.
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Blanco-Vogt, Ángela. "Methodology for high resolution spatial analysis of the physical flood susceptibility of buildings in large river floodplains." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-201193.
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The impacts of floods on buildings in urban areas are increasing due to the intensification of extreme weather events, unplanned or uncontrolled settlements and the rising vulnerability of assets. There are some approaches available for assessing the flood damage to buildings and critical infrastructure. To this point, however, it is extremely difficult to adapt these methods widely, due to the lack of high resolution classification and characterisation approaches for built structures. To overcome this obstacle, this work presents: first, a conceptual framework for understanding the physical flood vulnerability and the physical flood susceptibility of buildings, second, a methodological framework for the combination of methods and tools for a large-scale and high-resolution analysis and third, the testing of the methodology in three pilot sites with different development conditions. The conceptual framework narrows down an understanding of flood vulnerability, physical flood vulnerability and physical flood susceptibility and its relation to social and economic vulnerabilities. It describes the key features causing the physical flood susceptibility of buildings as a component of the vulnerability. The methodological framework comprises three modules: (i) methods for setting up a building topology, (ii) methods for assessing the susceptibility of representative buildings of each building type and (iii) the integration of the two modules with technological tools. The first module on the building typology is based on a classification of remote sensing data and GIS analysis involving seven building parameters, which appeared to be relevant for a classification of buildings regarding potential flood impacts. The outcome is a building taxonomic approach. A subsequent identification of representative buildings is based on statistical analyses and membership functions. The second module on the building susceptibility for representative buildings bears on the derivation of depth-physical impact functions. It relates the principal building components, including their heights, dimensions and materials, to the damage from different water levels. The material’s susceptibility is estimated based on international studies on the resistance of building materials and a fuzzy expert analysis. Then depth-physical impact functions are calculated referring to the principal components of the buildings which can be affected by different water levels. Hereby, depth-physical impact functions are seen as a means for the interrelation between the water level and the physical impacts. The third module provides the tools for implementing the methodology. This tool compresses the architecture for feeding the required data on the buildings with their relations to the building typology and the building-type specific depth-physical impact function supporting the automatic process. The methodology is tested in three flood plains pilot sites: (i) in the settlement of the Barrio Sur in Magangué and (ii) in the settlement of La Peña in Cicuco located on the flood plain of Magdalena River, Colombia and (iii) in a settlement of the city of Dresden, located on the Elbe River, Germany. The testing of the methodology covers the description of data availability and accuracy, the steps for deriving the depth-physical impact functions of representative buildings and the final display of the spatial distribution of the physical flood susceptibility. The discussion analyses what are the contributions of this work evaluating the findings of the methodology’s testing with the dissertation goals. The conclusions of the work show the contributions and limitations of the research in terms of methodological and empirical advancements and the general applicability in flood risk managementIn vielen Städten nehmen die Auswirkungen von Hochwasser auf Gebäude aufgrund immer extremerer Wetterereignisse, unkontrollierbarer Siedlungsbauten und der steigenden Vulnerabilität von Besitztümern stetig zu. Es existieren zwar bereits Ansätze zur Beurteilung von Wasserschäden an Gebäuden und Infrastrukturknotenpunkten. Doch ist es bisher schwierig, diese Methoden großräumig anzuwenden, da es an einer präzisen Klassifizierung und Charakterisierung von Gebäuden und anderen baulichen Anlagen fehlt. Zu diesem Zweck sollen in dieser Arbeit erstens ein Konzept für ein genaueres Verständnis der physischen Vulnerabilität von Gebäuden gegenüber Hochwasser dargelegt, zweitens ein methodisches Verfahren zur Kombination der bestehenden Methoden und Hilfsmittel mit dem Ziel einer großräumigen und hochauflösenden Analyse erarbeitet und drittens diese Methode an drei Pilotstandorten mit unterschiedlichem Ausbauzustand erprobt werden. Die Rahmenbedingungen des Konzepts grenzen die Begriffe der Vulnerabilität, der physischen Vulnerabilität und der physischen Anfälligkeit gegenüber Hochwasser ein und erörtern deren Beziehung zur sozialen und ökonomischen Vulnerabilität. Es werden die Merkmale der physischen Anfälligkeit von Gebäuden gegenüber Hochwasser als Bestandteil der Vulnerabilität definiert. Das methodische Verfahren umfasst drei Module: (i) Methoden zur Erstellung einer Gebäudetypologie, (ii) Methoden zur Bewertung der Anfälligkeit repräsentativer Gebäude jedes Gebäudetyps und (iii) die Kombination der beiden Module mit Hilfe technologischer Hilfsmittel. Das erste Modul zur Gebäudetypologie basiert auf der Klassifizierung von Fernerkundungsdaten und GIS-Analysen anhand von sieben Gebäudeparametern, die sich für die Klassifizierung von Gebäuden bezüglich ihres Risikopotenzials bei Hochwasser als wichtig erweisen. Daraus ergibt sich ein Ansatz zur Gebäudeklassifizierung. Die anschließende Ermittlung repräsentativer Gebäude beruht auf statistischen Analysen und Zugehörigkeitsfunktionen. Das zweite Modul zur Anfälligkeit repräsentativer Gebäude beruht auf der Ableitung von Funktion von Wasserstand und physischer Einwirkung. Es setzt die relevanten Gebäudemerkmale, darunter Höhe, Maße und Materialien, in Beziehung zum erwartbaren Schaden bei unterschiedlichen Wasserständen. Die Materialanfälligkeit wird aufgrund internationaler Studien zur Festigkeit von Baustoffen sowie durch Anwendung eines Fuzzy-Logic-Expertensystems eingeschätzt. Anschließend werden Wasserstand-Schaden-Funktionen unter Einbeziehung der Hauptgebäudekomponenten berechnet, die durch unterschiedliche Wasserstände in Mitleidenschaft gezogen werden können. Funktion von Wasserstand und physischer Einwirkung dienen hier dazu, den jeweiligen Wasserstand und die physischen Auswirkung in Beziehung zueinander zu setzen. Das dritte Modul stellt die zur Umsetzung der Methoden notwendigen Hilfsmittel vor. Zur Unterstützung des automatisierten Verfahrens dienen Hilfsmittel, die die Gebäudetypologie mit der Funktion von Wasserstand und physischer Einwirkung für Gebäude in Hochwassergebieten kombinieren. Die Methoden wurden anschließend in drei hochwassergefährdeten Pilotstandorten getestet: (i) in den Siedlungsgebieten von Barrio Sur in Magangué und (ii) von La Pena in Cicuco, zwei Überschwemmungsgebiete des Magdalenas in Kolumbien, und (iii) im Stadtgebiet von Dresden, das an der Elbe liegt. Das Testverfahren umfasst die Beschreibung der Datenverfügbarkeit und genauigkeit, die einzelnen Schritte zur Analyse der. Funktion von Wasserstand und physischer Einwirkung repräsentativer Gebäude sowie die Darstellung der räumlichen Verteilung der physischen Anfälligkeit für Hochwasser. In der Diskussion wird der Beitrag dieser Arbeit zur Beurteilung der Erkenntnisse der getesteten Methoden anhand der Ziele dieser Dissertation analysiert. Die Folgerungen beleuchten abschließend die Fortschritte und auch Grenzen der Forschung hinsichtlich methodischer und empirischer Entwicklungen sowie deren allgemeine Anwendbarkeit im Bereich des Hochwasserschutzes
El impacto de las inundaciones sobre los edificios en zonas urbanas es cada vez mayor debido a la intensificación de los fenómenos meteorológicos extremos, asentamientos no controlados o no planificados y su creciente vulnerabilidad. Hay métodos disponibles para evaluar los daños por inundación en edificios e infraestructuras críticas. Sin embargo, es muy difícil implementar estos métodos sistemáticamente en grandes áreas debido a la falta de clasificación y caracterización de estructuras construidas en resoluciones detalladas. Para superar este obstáculo, este trabajo se enfoca, en primer lugar, en desarrollar un marco conceptual para comprender la vulnerabilidad y susceptibilidad física de edificios por inudaciones, en segundo lugar, en desarrollar un marco metodológico para la combinación de los métodos y herramientas para una análisis de alta resolución y en tercer lugar, la prueba de la metodología en tres sitios experimentales, con distintas condiciones de desarrollo. El marco conceptual se enfoca en comprender la vulnerabilidad y susceptibility de las edificaciones frente a inundaciones, y su relación con la vulnerabilidad social y económica. En él se describen las principales características físicas de la susceptibilidad de edificicaiones como un componente de la vulnerabilidad. El marco metodológico consta de tres módulos: (i) métodos para la derivación de topología de construcciones, (ii) métodos para evaluar la susceptibilidad de edificios representativos y (iii) la integración de los dos módulos a través herramientas tecnológicas. El primer módulo de topología de construcciones se basa en una clasificación de datos de sensoramiento rémoto y procesamiento SIG para la extracción de siete parámetros de las edficaciones. Este módulo parece ser aplicable para una clasificación de los edificios en relación con los posibles impactos de las inundaciones. El resultado es una taxonomía de las edificaciones y una posterior identificación de edificios representativos que se basa en análisis estadísticos y funciones de pertenencia. El segundo módulo consiste en el análisis de susceptibilidad de las construcciones representativas a través de funciones de profundidad del impacto físico. Las cuales relacionan los principales componentes de la construcción, incluyendo sus alturas, dimensiones y materiales con los impactos físicos a diferentes niveles de agua. La susceptibilidad del material se calcula con base a estudios internacionales sobre la resistencia de los materiales y un análisis a través de sistemas expertos difusos. Aquí, las funciones de profundidad de impacto físico son considerados como un medio para la interrelación entre el nivel del agua y los impactos físicos. El tercer módulo proporciona las herramientas necesarias para la aplicación de la metodología. Estas herramientas tecnológicas consisten en la arquitectura para la alimentación de los datos relacionados a la tipología de construcciones con las funciones de profundidad del impacto físico apoyado en procesos automáticos. La metodología es probada en tres sitios piloto: (i) en el Barrio Sur en Magangué y (ii) en la barrio de La Peña en Cicuco situado en la llanura inundable del Río Magdalena, Colombia y (iii) en barrio Kleinzschachwitz de la ciudad de Dresden, situado a orillas del río Elba, en Alemania. Las pruebas de la metodología abarca la descripción de la disponibilidad de los datos y la precisión, los pasos a seguir para obtener las funciones profundidad de impacto físico de edificios representativos y la presentación final de la distribución espacial de la susceptibilidad física frente inundaciones El discusión analiza las aportaciones de este trabajo y evalua los resultados de la metodología con relación a los objetivos. Las conclusiones del trabajo, muestran los aportes y limitaciones de la investigación en términos de avances metodológicos y empíricos y la aplicabilidad general de gestión del riesgo de inundaciones
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Watkins, James Robert. "Evaluating the susceptibility of electronic components assembled with leaded solder to flexural failures, with high rate considerations." College Park, Md.: University of Maryland, 2008. http://hdl.handle.net/1903/8861.
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Thesis (Ph. D.) -- University of Maryland, College Park, 2008.Thesis research directed by: Dept. of Mechanical Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Sabahfar, Nassim. "Use of high-volume reclaimed asphalt pavement (RAP) for asphalt pavement rehabilitation." Thesis, Kansas State University, 2012. http://hdl.handle.net/2097/15107.
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Master of ScienceDepartment of Civil Engineering
Mustaque Hossain
Because of recent rises in asphalt binder prices, state agencies and contractors are now willing to use higher volumes of reclaimed asphalt pavement (RAP). In this project, the effects of increasing RAP percentage and using fractionated RAP (FRAP) in hot-mix asphalt (HMA) mixtures have been studied. Fractionation involved processing and separating of RAP materials into at least two sizes, typically a coarse fraction and a fine fraction. This study evaluated the effects of increasing the proportions of RAP and FRAP on moisture resistance, rutting, and fatigue cracking of Superpave mixtures. Furthermore, the effect of using different sources of RAP in the mix has been investigated. HMA mixtures with five varying RAP and FRAP contents (20, 30, and 40% RAP, and 30 and 40% FRAP) were studied. The Hamburg wheel-tracking device (HWTD) test (TEX-242-F), the Kansas standard test method no. 56 (KT-56), or modified Lottman test, and the dynamic modulus test (AASHTO TP: 62-03) were used to predict moisture damage, rutting potential, and fatigue cracking resistance of the mixes. HMA specimens were made based on Superpave HMA mix design criteria for 12.5-mm (1/2-inch) nominal maximum aggregate size (NMAS) and compacted using the Superpave gyratory compactor. For the first source of RAP, results of this study showed that although mixture performance declined as the percentage of RAP increased, mixtures with even 40% RAP met minimum performance requirements. The second source of RAP, however, almost failed to meet minimum requirements even at 20% RAP. Results proved the maximum percentage of RAP allowed in the mix is highly influenced by its source. Although some improvements have been observed, especially for the second source of RAP, when RAP is compared to FRAP, FRAP does not seem to considerably affect performance of the HMA mixture.
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Islam, R. S. "Influence of hole content and controlled disorder on the magnetic susceptibility, isotope exponents and resistivity of high-Tc cuprates." Thesis, University of Cambridge, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.604969.
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The uniform magnetic susceptibility of La2-xSrxCu1-yZnyO4 has been investigated over a wide range of impurity (Zn) concentration for different planar carrier (hole) content, p (º x, for this system), extending from underdoped to heavily overdoped regions. A doping dependent Zn-induced magnetic behaviour is observed for these compounds. The apparent Zn induced moment (expressed as peff2/Zn in units of mB2) is larger in the underdoped side and, decreases quite sharply around p ~ 0.19,without much change for further overdoping. This indicates a possible role of the pseudogap on the Zn induced magnetic behaviour, as there are indications that the pseudogap is present only for p £ 0.19. It is shown that the data can also be interpreted in terms of a Zn-induced low energy quasiparticle resonance that depends on the presence of the pseudogap. The oxygen isotope exponents in superconducting transition temperature and superfluid density, a(Tc) and aps), respectively, have been studied as a function of hole (x) and impurity (y) contents in La2-xSrxCu1-yZnyO4. The isotope exponents displayed a canonical relationship, except around the region of x ~ 1/8. The results are discussed in terms of the presence of the pseudogap and the stripe correlations. In-plane resistivity measurements under applied magnetic fields (up to 12 Tesla), pab(T,H), have been carried out on c-axis oriented thin films of Y0.95Ca0.05Ba2(Cu1-yZny)3O7-d with varying amount of in-plane disorder (Zn) and hole concentration. Following an earlier work on sintered compounds of the same system, we have obtained supplementary information about the characteristic pseudogap temperature, T*(p), from the analysis of the pab(T,H) data. Our thin film data support the earlier findings that T*(p) falls below Tc0(p) (º Tc(p) for pure compound) in the overdoped side and, extrapolates to zero at p ~ 0.19.
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Smith, Brian Donald. "The influence of high temperature stress and herbicides on the susceptibility of creeping bentgrass (Agrostis palustris) to Curvularia lunata." Thesis, Virginia Polytechnic Institute and State University, 1989. http://hdl.handle.net/10919/74538.
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The status of Curvularia lunata as a primary pathogen of creeping bentgrass (Agrostis palustris) has been debated in the literature for many years. The most recent and most complete evidence indicates that this fungus is a weak pathogen, colonizing only senescing tissues. In the present study, four groups of experiments were conducted: 1) The effects of five herbicides on the growth of C. lunata in vitro were determined. 2) Acute high temperature stress was evaluated as a predisposing factor in the susceptibility of creeping bentgrass to C. lunata. 3) The effects of acute high temperature stress and exposure to five different herbicides on creeping bentgrass were evaluated together and separately. 4) The potential of chronic, moderately high temperature stress and exposure to five herbicides when occurring separately and together to serve as predisposing factors on the susceptibility of creeping bentgrass to C. lunata were evaluated. It was found that effects of the herbicides on the growth of C. lunata depend on both the specific herbicide and the concentration. High temperature stress and herbicide exposure increase the colonization of creeping bentgrass by C. lunata only to the extent that these treatments produce moribund plant tissue.Master of Science
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Marin, Córdoba Roberto. "Chromium carcinogenesis characterization of DNA damaging intermediates by EPR ³¹P NMR, HPLC, ESI-MS and magnetic susceptibility /." Ohio : Ohio University, 2010. http://www.ohiolink.edu/etd/view.cgi?ohiou1261417590.
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Kaskar, Rafee'ah. "Effect of melatonin on myocardial susceptibility to ischaemia and reperfusion damage in a rat model of high-fat diet-induced obesity." Thesis, Stellenbosch : Stellenbosch University, 2015. http://hdl.handle.net/10019.1/97868.
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Thesis (MScMedSc)--Stellenbosch University, 2015.ENGLISH ABSTRACT: Obesity has reached epidemic proportions worldwide and is currently a serious health problem. It is associated with metabolic abnormalities, oxidative stress, hypertension, insulin resistance and an increased disposition for the development of cardiovascular disease. Elucidation of the pathophysiological mechanisms underlying obesity and its relationship with metabolic and cardiovascular diseases is essential for prevention and management of these disorders. Melatonin, the pineal gland hormone, is a powerful antioxidant and has been shown to protect the myocardium against ischaemia/reperfusion (I/R) injury. Long- as well as shortterm melatonin treatment also reversed several of the harmful effects of obesity in an animal model of hyperphagia-induced obesity (DIO). However, its effects on myocardial I/R injury and intracellular signalling in obesity induced by a high fat diet (HFD) are still unknown. Aims of study: (i) To evaluate the ability of a high fat diet (HFD) to induce obesity in rats. Apart from evaluating its effects on the biometric parameters and resistance to ischaemia/reperfusion injury (as indicated by infarct size in regional ischaemia and functional recovery after global ischaemia), special attention will be given on the interplay between adiponectin, AMPK, leptin, and FFA in this model. (ii) To evaluate the effect of daily oral administration of melatonin to rats on the HFD as well as their littermate controls, on the parameters listed above as well as on the development of obesity. In this study melatonin will be administered from the onset of the feeding of the high fat diet. Methods: Male Wistar rats were divided into 4 groups: (i) control rats (receiving normal rat chow) (C); (ii) control rats receiving melatonin (CM); (iii) obese rats (receiving HFD) (HFD); (iv) obese rats receiving melatonin (HM). Animals were kept on the diet for 16 weeks and melatonin treatment (10mg/kg/day, added to the drinking water) started at the onset of the feeding. Following feeding and treatment, the animals were grouped into fasted/ non-fasted of which biometric parameters were recorded and blood collected at the time of sacrifice for metabolic and biochemical assays. Hearts were perfused in the working mode for evaluation of myocardial function and infarct size determination after exposure to 35min regional ischaemia/60min reperfusion. For study of intracellular signaling, hearts were perfused in the working mode, subjected to 20min global ischaemia/10min reperfusion and freeze-clamped for Western blotting. Plasma leptin, adiponectin, free fatty acid, triglycerides, total cholesterol, phospholipids, conjugated dienes and thiobarbituric reactive substances (TBARS) levels were determined. Several kinases were investigated including, the RISK (reperfusion injury salvage kinase) (PKB/Akt and ERK p44/42) and SAFE (survivor activating factor enhancement) (STAT-3) pathways, AMPK and JNK under baseline conditions or following 10 min reperfusion. In addition, expression of UCP-3 and PGC1-α was determined. Results: Significant increases in body weight, visceral fat, blood glucose, insulin, HOMA index and leptin and a reduction in adiponectin levels were observed in the fasted high fat diet (HFD) group when compared with controls (C). Significant increases in free fatty acid and triglyceride levels were also noted the HFD group while other serum lipid parameters, including TBARS, remained unchanged. No differences in functional recovery during reperfusion or infarct size after exposure to 35 min regional ischaemia, as well as functional recovery during reperfusion after 20 min global ischaemia were observed between the control and HFD groups. Baseline and 10 min reperfusion data were similar for the RISK and SAFE pathway kinases for the control vs HFD groups. The HFD also had no effect on the expression and phosphorylation of myocardial AMPK and JNK, as well as on the expression of UCP-3 and PGC1-α, when compared to the controls. Treatment with melatonin significantly reduced body weight, visceral fat, blood glucose, HOMA index and serum leptin levels in HFD treated groups, while having no effect on the lipid profile. Although melatonin significantly reduced infarct size in both control [% of area at risk: 20.59 ± 2.29 (CM) vs 38.08 ± 2.77 (C)] and high-fat diet groups [% of area at risk: 11.43 ± 2.94 (HM) vs 38.06 ± 3.59 (H)], it was without effect on myocardial functional recovery during reperfusion. Melatonin had no effect on the intracellular signaling pathways studied. Conclusions: The HFD proved to be a useful model of diet-induced obesity with a more pronounced impact on biometric and metabolic changes compared to the DIO model. Long-term melatonin treatment successfully prevented the development of metabolic abnormalities associated with the high fat diet and obesity as well as significantly reduced myocardial infarct size. The mechanisms involved in melatonin-induced cardioprotection in obesity have not been fully elucidated in this study and require further investigation. However, the anti-obesogenic and cardioprotective properties of melatonin were very significant indeed and support the suggestion of this hormone as a potential tool in the treatment of obesity and associated cardiovascular complications.
AFRIKAANSE OPSOMMING: Inleiding: Vetsug (obesiteit) het wêreldwyd epidemiese afmetings aangeneem en word tans as ‘n ‘n ernstige gesondheidsprobleem beskou. Vetsug word geassosieer met metaboliese afwykings, oksidatiewe stres, hipertensie, insulienweerstandigheid en is‘n belangrike risikofaktor vir die ontwikkeling van kardiovaskulêre siekte. Ten spyte hiervan, het onlangse studies ‘n gunstige effek van vetsug op die uitkomste van miokardiale infarksie in pasiënte gerapporteer, die sg obesiteitsparadoks. Kennis van die patofisiologiese meganismes onderliggend aan vetsug en die ontstaan van metaboliese afwykinge en hartsiekte is noodsaaklik vir die voorkoming en behandeling van hierdie toestande. Melatonien, die hormoon afgeskei deur die pineaalklier, is ‘n kragtige antioksidant en vry radikaal opruimer. Dit is voorheen aangetoon dat dit die hart teen iskemie/herperfusie (I/H) besering kan beskerm en sommige van die skadelike gevolge van vetsug in diermodelle kan omkeer. Die effek van melatonien op miokardiale I/H besering en intrasellulêre seintransduksie prosesse in vetsug geïduseer deur ‘n hoë vet dieet is egter nog onbekend. Doelstellings: (i) Die ontwikkeling en karakterisering van ‘n nuwe model van vetsug en insulienweerstandigheid geïnduseer deur 'n hoë vet dieet (HVD) en die evaluering van die effek daarvan op miokardiale I/H besering en die gepaardgaande intrasellulêre seintransduksieprosesse; (ii) Bepaling van die effek van daaglikse toediening van melatonien aan rotte op die HVD sowel as aan kontroles op ‘n standard dieet, op die ontwikkeling van dieet-geïnduseerde metaboliese veranderinge, miokardiale infarktgrootte en funksionele herstel na koronêre arterie afbinding, sowel as intrasellulêre seintransduksie. Metodiek: Vier groepe van manlike Wistar rotte is bestudeer: (i) kontrole rotte (op‘n standaard dieet) (K); (ii) kontrole rotte op ‘n standard dieet plus melatonien (KM); (iii) dieetrotte (op‘n HVD); (iv) HVD rotte wat melatonien ontvang (HM). Die HVD en melatonien (10mg/kg/dag in die drinkwater) is vir 16 weke toegedien. Na die periode van behandeling, is die diere in vastende en nie-vastende groepe verdeel, die biometriese parameters genoteer en bloedmonsters vir metaboliese en biochemiese bepalings versamel, tydens verwydering van die harte. Harte is geperfuseer volgens die werkhartmodel vir bepaling van miokardiale funksie en infarktgrootte na blootstelling aan 35min streeksiskemie. Vir evaluering van intrasellulêre seintransduksie, is geperfuseerde werkende rotharte blootgestel aan 15min globale iskemie/10 min herperfusie en gevriesklamp vir latere analises volgens die Western kladtegniek.hart. Serum leptien, adiponektien, vryvetsure, trigliseried, totale cholesterol, fosfolipiede, gekonjugeerde diene en tiobarbituursuur reaktiewe stowwe (TBARS) is bepaal. Met gebruik van Western kladtegniek, is die aktivering en/of uitdrukking van die RISK (PKB/ Akt en ERK p44/42) en SAFE (STAT-3) seintransduksiepaaie, AMPK, JNK, UCP-3 en PGC1-α, onder basislyn toestande of na 10 min herperfusie bestudeer. Resultate:‘n Beduidende toename in liggaamsgewig, visserale vet, die HOMA indeks, insulien en leptien vlakke is in die HVD groep waargeneem vergeleke met die kontrole (K) rotte. Adiponektien vlakke was laer in die HVD groep. Die HVD groep is ook gekenmerk deur ‘n beduidende styging in serum vryvetsuur en trigliseried vlakke, terwyl die ander lipied parameters, insluitende die TBARS vlakke, onveranderd was. Infarktgrootte en funksionele herstel tydens herperfusie na blootstelling aan 35 min streeksiskemie, asook funksionele herstel tydens herperfusie na 20 min globale iskemie het nie verskil tussen harte van die kontrole en HVD rotte nie. Aktivering van PKB/Akt, ERK p44/p42, STAT3, AMPK en JNK by basislyn en na 10 min herperfusie was soortgelyk in die kontrole en HFD groepe. Die HVD het ook geen effek op die uitdrukking van UCP-3 en PGC1-α in vergelyking met die kontrole gehad nie. Behandeling met melatonien het die liggaamsgewig, visserale vet, bloedglukose, HOMA indeks en serum leptien vlakke in die HVD groepe statisties beduidend verlaag, terwyl dit geen invloed op die lipiedprofiel gehad het nie. Melatonien behandeling het die miokardiale infarktgrootte beduidend en tot dieselfde mate verminder in beide kontrole [20.59 ± 2.29 (KM) vs 38.08 ± 2.77% (K)] en HVD groepe [11.43 ± 2.94 (HM) vs 38.06 ± 3.59% (HVD)]. Geen verskille is egter tussen die funksionele herstel gedurende herperfusie van die behandelde en onbehandelde kontrole en HVD groepe waargeneem nie. Melatonien het ook geen uitwerking op die intrasellulêre seintransduksiepaaie gehad nie. Gevolgtrekkings: Die resultate het getoon dat die HFD 'n goeie model van dieetgeïnduseerde vetsug en insulien weerstandigheid ontlok, met 'n meer uitgesproke impak op biometriese en metaboliese veranderinge as die voorheen gebruikte hoë-sukrose dieet. Langtermyn melatonien- behandeling het die ontwikkeling van metaboliese abnormaliteite geassosieer met die HVD, voorkom, asook miokardiale infarktgrootte na koronêre afbinding beduidend verminder. Die meganismes betrokke in melatonien-geïnduseerde miokardiale beskerming moet egter in meer detail ondersoek word. Die resultate verkry steun die voorstel dat melatonientoediening voordelig sal wees in die behandeling van vetsug en sy kardiovaskulêre komplikasies.
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Farmer, Samantha. "Analysis and Risk Estimation of High Priority Unstable Rock Slopes in Great Smoky Mountains National Park, Tennessee and North Carolina." Digital Commons @ East Tennessee State University, 2021. https://dc.etsu.edu/etd/3953.
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Great Smoky Mountains National Park (GRSM) received 12.5 million visitors in 2020. With a high traffic volume, it is imperative roadways remain open and free from obstruction. Annual unanticipated rockfall events in GRSM often obstruct traffic flow. Using the Unstable Slope Management Program for Federal Land Management Agencies (USMP for FLMA) protocols, this study analyzes high priority unstable rock slopes through 1) creation of an unstable slope geodatabase and 2) generation of a final rockfall risk model using Co-Kriging from a preliminary risk model and susceptibility model. A secondary goal of this study is to provide risk estimation for the three most traveled transportation corridors within GRSM, as well as investigate current rockfall hazard warning sign location to ultimately improve visitor safety with regards to rockfall hazards.
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Cevik, Gul. "Investigation Of The Effect Of Orientation And Heat Treatment On The Stress Corrosion Cracking Susceptibility Of 7050 Aluminum Alloy." Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/3/12605220/index.pdf.
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In the present work, the effect of variation in specimen orientation and heat treatment on the Stress Corrosion Cracking (SCC) susceptibility of 7050 aluminum alloy was investigated in 3,5% NaCl solution and under freely corroding conditions. For this purpose, Constant Extension Rate Tests (CERT) was performed on precracked Compact Tension (CT) specimens and the Direct Current Potential Drop technique was applied to measure the crack lengths. In addition to crack length versus time curves, the relationship between the crack growth rate and the stress intensity factor was determined. Fractographic analysis was utilized extensively to support the findings related with basic mechanisms of cracking.
The alloy was found to be in the most susceptible state in the SL orientation, in which the crack propagation direction is parallel to the rolling direction. The resistance to SCC is higher in the TS but at maximum in LT orientation where the loading direction is parallel to the rolling direction.
In the peak aging treatment, T651, alloy is susceptible to SCC in SL orientation. When the over aging treatment, T7651, is applied the resistance is increased and the two step over aging treatment, T73651, has resulted in an additional improvement in this orientation. On the other hand, the alloy showed higher resistance to SCC in TS and LT orientations in T651 condition compared to the T7651 and T73651 treatments. In these orientations, the alloy is less susceptible in T73651 condition than in T7651 treatment.
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Wokoma, Ekanem C. W. "The effects of high temperature stress and nutrient release from maize (Zea mays L.) leaves on susceptibility to Bipolaris maydis (Nisikado) Shoemaker /." The Ohio State University, 1986. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487323583623123.
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Kasch, Juliane [Verfasser], and Susanne [Akademischer Betreuer] Klaus. "Impact of maternal high-fat consumption on offspring exercise performance, skeletal muscle energy metabolism, and obesity susceptibility / Juliane Kasch ; Betreuer: Susanne Klaus." Potsdam : Universität Potsdam, 2018. http://d-nb.info/1218403527/34.
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Le, Poul Nicolas. "Charge transfer at the high-temperature superconductor/liquid electrolyte interface." Thesis, University of Exeter, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.391279.
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Nwabueze, Christian, Liang Wang, Fenose Osedeme, Michelle McNabb, Joshua Yang, Rafie Boghozian, David Wood, and Hadii Mamudu. "Understanding the association between susceptibility to smoke e-cigarettes and the actual use of e-cigarette among school-going youths in rural appalachia." Digital Commons @ East Tennessee State University, 2020. https://dc.etsu.edu/etsu-works/7675.
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Background: The Central Appalachian region of the United States is disproportionately burdened with high prevalence of tobacco use and tobacco-induced diseases. Efforts to address tobacco use in the region have become complicated with uptake of Electronic Nicotine Products (ENPs), including e-cigarettes, among adolescents and young adults. The high prevalence of tobacco use, and the history of tobacco production have created a high-risk environment for the use of tobacco and ENP among adolescents in the region. However, research on how susceptibility to use e-cigarettes among school-going adolescents translates to usage is sparse. This study aimed to explore the association between susceptibility to use e-cigarette and e-cigarette use in school-going adolescents in Appalachian Tennessee.
Methods: Data (N=399) was collected from high school students in an Appalachian Regional Commission (ARC)-designated distressed County in Appalachian Tennessee. We ascertain the study’s outcomes (current e-cigarette use), the exposure (susceptibility to use e-cigarette) and co-variates (grade, sex, age at first use of tobacco, perception of the danger of smoking, parental counseling) using validated questions. Descriptive statistics and multi-variable logistics analyses were performed. The Odds Ratios (ORs) along with Confidence Intervals (CI) have been reported.
Results: 15.5% of the population were current e-cigarette users and 25.93% were identified as susceptible to use e-cigarettes. Susceptibility to use e–cigarette was associated with increased odds of the current use of e-cigarette (OR=6.40, CI=4.18–9.77). In addition, age at first use of tobacco (OR = 0.42, 95%CI =0.32 – 0.56) was associated with reduced odds of the current use of e-cigarette, while intention to smoke e-cigarette (OR =6.46, CI =3.63 -11.49) was associated with increased odds of the current use of e-cigarette.
Conclusion: Susceptibility to use e-cigarette was positively associated with the current use of e-cigarette among school going adolescents. Future longitudinal studies with large sample size are warranted to confirm the association.
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Fahlström, Karl. "Laser welding of boron steels for light-weight vehicle applications." Licentiate thesis, Högskolan Väst, Forskningsmiljön produktionsteknik(PTW), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:hv:diva-7263.
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Laser beam welding has gained a significant interest during the last two decades. The suitability of the process for high volume production has the possibility to give a strong advantage compared to several other welding methods. However, it is important to have the process in full control since various quality issues may otherwise occur. During laser welding of boron steels quality issues such as imperfections, changes in local and global geometry as well as strength reduction can occur. The aspects that need to be considered are strongly depending on alloy content, process parameters etc. These problems that can occur could be fatal for the construction and the lowest level of occurrence is wanted, independent of industry. The focus of this study has been to investigate the properties of laser welded boron steel. The study includes laser welding of boron alloyed steels with strengths of 1500 MPa and a recently introduced 1900 MPa grade. Focus has been to investigate weldability and the occurrence of cracks, porosity and strength reducing microstructure that can occur during laser welding, as well as distortion studies for tolerances in geometry. The results show that both conventional and 1900 MPa boron alloyed steel are suitable for laser welding. Due to the martensitic structure of welds the material tends to behave brittle. Cracking and porosity do not seem to be an issue limiting the use of these steels. For tolerances in geometry for larger structures tests has been done simulating laser welding of A-pillars and B-pillars. Measurements have been done with Vernier caliper as well as a more advanced optical method capturing the movements during the welding sequence. Results from the tests done on Ushaped beams indicates that depending on the geometry of the structure and heat input distortions can be controlled to give distortions from 1 to 8 mm, at a welding length of 700 mm. This means that important geometry points can be distorted several millimeters if the laser welding process not is controlled.
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Rau, Mandy Kim [Verfasser], and Sotirios [Akademischer Betreuer] Bisdas. "Comparative Evaluation of Prognostic Value of Arterial Spin Labelling and Dynamic Susceptibility Contrast-Enhanced MR Imaging in High-Grade Gliomas / Mandy Kim Rau ; Betreuer: Sotirios Bisdas." Tübingen : Universitätsbibliothek Tübingen, 2018. http://d-nb.info/1198972548/34.
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Lenzo, Jansen C. Lenzo. "Evaluation of the Effect of Tungsten and Boron Additions on the Microstructure and Solidification Cracking Susceptibility of Fe-Mn-C Filler Metals." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1470829433.
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Blanco-Vogt, Ángela [Verfasser], Jochen [Akademischer Betreuer] Schanze, Norbert [Akademischer Betreuer] Haala, and Elmar [Gutachter] Csaplovics. "Methodology for high resolution spatial analysis of the physical flood susceptibility of buildings in large river floodplains / Ángela Blanco-Vogt. Betreuer: Jochen Schanze ; Norbert Haala. Gutachter: Elmar Csaplovics." Dresden : Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://d-nb.info/1102086258/34.
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Vallée, Maxime. "Design of an internet tool to assess variants of uncertain clinical significance in high-risk breast cancer genes BRCA1 and BRCA2." Thesis, Lyon 1, 2012. http://www.theses.fr/2012LYO10193.
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Des mutations germinales dans les gènes majeurs du cancer du sein BRCA1 et BRCA2 sont responsables de la maladie chez les patientes cumulant histoire familiale et apparition du cancer à un jeune âge. Environ 15% des femmes testées pour les mutations de BRCA1 et BRCA2 sont porteuses d’une mutation clairement pathogénique dans un des deux gènes. Cependant, des variants de signification clinique incertaine (VUS pour "variants of uncertain clinical significance") sont détectés dans 5% à 15% des cas testés. Pour évaluer la signification clinique des VUS, le Breast cancer Infomation Core (BIC) a développé un modèle Bayésien intégré, basé sur des données d'observations. Align-GVGD, un algorithme d'évaluation des substitutions faux-sens basé sur l'histoire évolutionnaire de la protéine fournit la probabilité a priori du modèle. Cependant, lorsqu'une substitution silencieuse est détectée, elle sera jugée comme neutre par l'évaluation in silico. Pourtant, une mutation au niveau de l'ARNm peut perturber la mécanique de l'épissage, par deux moyens principaux: endommagement des sites sauvages d'épissage, ou la création de sites exoniques d'épissage de novo. Notre premier objectif est de rassembler les variants déjà publiés, de les re-analyser avec le modèle d'évaluation intégrée. Nous voulons extraire le plus de variants publiés premièrement sous le statut de VUS vers un statut plus informatif, avec des recommandations cliniques associées. Par la suite, nous voulons étendre le modèle pour évaluer plus de variants, plus précisément, en intégrant l'évaluation des perturbations de l'épissage. Finalement, nous serons capable de présenter et de fournir ces informations librement sur Internet, via une interface web populaire, une Leiden Open Variation Database (LOVD)Germline mutations in major breast cancer susceptibility genes BRCA1 and BRCA2 are responsible for the disease for high-risk patients (patients with early onset and familial history of breast cancer). Around 15% of screened women for BRCA1 and BRCA2 mutations carry one clearly pathogenic mutation in one of those two genes. However, variants of uncertain clinical significance (VUS) are detected in 5% to 15% of tested patients. To assess clinical significance of VUS, the Breast cancer Information Core (BIC) has developed a Bayesian integrated model, based on observational data. Align-GVGD, an algorithm evaluating damage of missense substitutions based on the evolutionary history of the protein, is providing the prior probability of the model. However, whenever a silent substitution arise, it is firstly treated as neutral by the in silico assessment. Indeed, a mutation at the mRNA level can disrupt the splicing machinery by two main means: damaging wild-type splice sites, or creating exonic de novo splice sites. Our first goal is to be a central repository of already published variants, to re-analyze them using the unified integrated evaluation model. We would like to extract the most variants from the original published status of VUS to a more informative status, with associated clinical recommendations. Then we would like to extend the model to be able to evaluate more variants more precisely by adding the splicing damages assessment in the integrated evaluation. In the end, we will be able to provide these informations freely on Internet, via a widely use web interface, a Leiden Open Variation Database (LOVD)
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Ghazanfari, Nader. "Effects Of Nb2o5 Addition On The Formation And Properties Of Bi-based Superconductors." Master's thesis, METU, 2006. http://etd.lib.metu.edu.tr/upload/12607468/index.pdf.
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Effects of Nb2O5 addition on the formation and properties of the Bi-based superconductors were studied. The superconducting samples were synthesized by two different methods, the solid state reaction (SSR) and ammonium nitrate melt route (ANM) to obtain information about the growth techniques. Ten samples (five with each method) with the chemical compositions of Bi1.6Pb0.4Sr2Ca2Cu3NbxOy, with x= 0.00, 0.05, 0.10, 0.20, and 0.30 were prepared.
Phase identification, structural and microstructural analysis were carried out using powder X-ray diffraction method, scanning electron microscopy and energy dispersive X-ray (EDX) analysis. The transition temperature and the critical current measurements were carried out using the electromagnetic measurement system. The critical parameters of the samples were also determined by AC susceptibility and magnetization measurements.
Improvements in the formation of the Bi-2223 phase with Nb addition have been observed by both methods. The ANM method leads mixtures of Bi-2223 and Bi-2212 phases, but with the SSR method pure Bi-2223 phase was obtained.
With small amounts of Nb addition the critical temperature, Tc, remains the same for ANM samples and it increases for the SSR samples. For both series of samples Tc decreases with further increase of Nb content. With Nb addition the critical currents of the ANM sample almost remain the same and those of the SSR samples increases.
Observations based on AC susceptibility measurements showed that Nb addition improve inter-grain coupling. Inductive critical current densities obtained from magnetization measurements agree with the critical currents stated above and show that Jc increase with increase Nb content.
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Cunha, Henrique Noguez da. "Avaliação da suscetibilidade à erosão da bacia hidrográfica do Alto Camaquã - RS." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2016. http://hdl.handle.net/10183/140931.
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A exploração excessiva dos recursos naturais e o uso desordenado do espaço buscando uma rentabilidade máxima dos sistemas, originou uma intensa preocupação com as implicações ambientais resultantes da falta de gestão do espaço natural. Para o estudo dos processos de degradação ambiental é necessário analisar os elementos do meio físico e antrópico que participam desse processo, onde a espacialização das informações requer a utilização de sistemas e modelos nos quais seja possível integrar os dados. Nesse sentido, o objetivo do presente trabalho foi avaliar e espacializar os graus de suscetibilidade à erosão na Bacia Hidrográfica do Alto Camaquã com base em geotecnologias, em especial o sensoriamento remoto e o Sistema de Informações Geográficas. Foram avaliados os aspectos físicos e antrópicos da bacia hidrográfica de acordo com o grau de suscetibilidade à erosão. Os resultados da suscetibilidade à erosão da Bacia Hidrográfica do Alto Camaquã tenderam à “estabilidade/ suscetibilidade mediana” com 3.111,5 km² (60,7%) e menor representação das classes “Estável” com 138,4 km² (2,7%), Moderadamente Estável” com 1358,4 km² (26,5%), “Moderadamente Suscetível” com 389,5 km² (7,6%) e “Suscetível” com 128,2 km² (2,5%), contudo, a avaliação dos parâmetros físicos e antrópicos analisados separadamente resultaram em duas regiões distintas. (1) Na região oeste os aspectos físicos tendem à estabilidade e os aspectos antrópicos à suscetibilidade, caracterizados pela mecanização agrícola sobre relevo plano à suave ondulado. (2) Na região leste, o meio físico tende à suscetibilidade e o uso da terra à estabilidade, cujo relevo apresenta, em grande parte, alta declividade e presença de morros com afloramento rochoso, condições inaptas às atividades agrícolas intensivas.The excessive exploration of natural resources and the uncontrolled use of the territory, seeking a maximum profitability of the systems, has caused an intense concern about the environmental implications arising from lack of management of the natural areas. The environmental degradation processes are analyzed by the physical environment elements and the land covers and land uses included in the process, when data are integrated by geographical information systems and spatial models. In this sense, the objective of this study was to evaluate the susceptibility to erosion in the watershed of the Upper Camaquã river based on geotechnology, with emphasis in remote sensing and Geographic Information Systems. We evaluated the physical and anthropic aspects of the watershed according to the degree of susceptibility to erosion The Upper Camaquã watershed showed "stability/median susceptibility" with 3.111,5 square kilometers (60,7%) and lower representation of classes "Stable" with 138.4 km² ( 2.7%) “Moderately Stable " with 1358.4 square kilometers (26.5%) , " Moderately Susceptible" with 389.5 km² (7.6%) and "Susceptible" with 128.2 square kilometers (2.5%), however, two regions occurred when the physical and anthropogenic components were considered separately: (1) The western region with stable physical aspects, susceptible anthropogenic aspects and agricultural mechanization on flat to gently rolling terrains; (2) the eastern region with susceptible physical environment, stable land use, where terrain has largely, steep slopes and hilly terrains with rocky outcrop, unfit conditions to intensive agricultural activities.
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Xu, Jinghao. "Alloy Design and Characterization of γ′ Strengthened Nickel-based Superalloys for Additive Manufacturing." Licentiate thesis, Linköpings universitet, Konstruktionsmaterial, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-173042.
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Nickel-based superalloys, an alloy system bases on nickel as the matrix element with the addition of up to 10 more alloying elements including chromium, aluminum, cobalt, tungsten, molybdenum, titanium, and so on. Through the development and improvement of nickel-based superalloys in the past century, they are well proved to show excellent performance at the elevated service temperature. Owing to the combination of extraordinary high-temperature mechanical properties, such as monotonic and cyclic deformation resistance, fatigue crack propagation resistance; and high-temperature chemical properties, such as corrosion and oxidation resistance, phase stability, nickel-based superalloys are widely used in the critical hot-section components in aerospace and energy generation industries. The success of nickel-based superalloy systems attributes to both the well-tailored microstructures with the assistance of carefully doped alloying elements, and the intently developed manufacturing processes. The microstructure of the modern nickel-based superalloys consists of a two-phase configuration: the intermetallic precipitates (Ni,Co)3(Al,Ti,Ta) known as γ′ phase dispersed into the austenite γ matrix, which is firstly introduced in the 1940s. The recently developed additive manufacturing (AM) techniques, acting as the disruptive manufacturing process, offers a new avenue for producing the nickel-based superalloy components with complicated geometries. However, γ′ strengthened nickel-based superalloys always suffer from the micro-cracking during the AM process, which is barely eliminated by the process optimization. On this basis, the new compositions of γ′ strengthened nickel-based superalloy adapted to the AM process are of great interest and significance. This study sought to design novel γ′ strengthened nickel-based superalloys readily for AM process with limited cracking susceptibility, based on the understanding of the cracking mechanisms. A two-parameter model is developed to predict the additive manufacturability for any given composition of a nickel-based superalloy. One materials index is derived from the comparison of the deformation-resistant capacity between dendritic and interdendritic regions, while another index is derived from the difference of heat resistant capacity of these two spaces. By plotting the additive manufacturability diagram, the superalloys family can be categorized into the easy-to-weld, fairly-weldable, and non-weldable regime with the good agreement of the existed knowledge. To design a novel superalloy, a Cr-Co-Mo-W-Al-Ti-Ta-Nb-Fe-Ni alloy family is proposed containing 921,600 composition recipes in total. Through the examination of additive manufacturability, undesired phase formation propensity, and the precipitation fraction, one composition of superalloy, MAD542, out of the 921,600 candidates is selected. Validation of additive manufacturability of MAD542 is carried out by laser powder bed fusion (LPBF). By optimizing the LPBF process parameters, the crack-free MAD542 part is achieved. In addition, the MAD542 superalloy shows great resistance to the post-processing treatment-induced cracking. During the post-processing treatment, extensive annealing twins are promoted to achieve the recrystallization microstructure, ensuring the rapid reduction of stored energy. After ageing treatment, up to 60-65% volume fraction of γ′ precipitates are developed, indicating the huge potential of γ′ formation. Examined by the high-temperature slow strain rate tensile and constant loading creep testing, the MAD542 superalloy shows superior strength than the LPBF processed and hot isostatic pressed plus heat-treated IN738LC superalloy. While the low ductility of MAD542 is existed, which is expected to be improved by modifying the post-processing treatment scenarios and by the adjusting building direction in the following stages of the Ph.D. research. MAD542 superalloy so far shows both good additive manufacturability and mechanical potentials. Additionally, the results in this study will contribute to a novel paradigm for alloy design and encourage more γ′-strengthened nickel-based superalloys tailored for AM processes in the future.Additional funding agencies: Agora Materiae Graduate School for multidisiplinary PhD students at Linköping University, and Stiftelsen Axel Hultgren.
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Fresneau, Brice. "Analyses pronostiques en oncologie pédiatrique : Identification de facteurs de susceptibilité tumorale ou individuelle à l’efficacité et/ou à la toxicité des traitements anticancéreux utilisés chez l’enfant Investigating the Heterogeneity of Alkylating Agents' Efficacy and Toxicity Between Sexes: A Systematic Review and Meta-Analysis of Randomized Trials Comparing Cyclophosphamide and Ifosfamide (MAIAGE Study) Is Alpha-Fetoprotein Decline a Prognostic Factor of Childhood Non-Seminomatous Germ Cell Tumours? Results of the French TGM95 Study New Insight into Severe Ototoxicity after Childhood Cancer. Is there an Impact of Melphalan and Busulfan? A French Childhood Cancer Survivor Study A Pharmacokinetic and Pharmacogenetic Analysis of Osteosarcoma Patients Treated with High-Dose Methotrexate: Data from the OS2006/Sarcoma-09 Trial." Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPASS034.
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Les progrès thérapeutiques en oncologie pédiatrique ont permis une amélioration des taux de survie qui dépassent aujourd’hui 80%. De façon à augmenter les taux de guérison et diminuer les complications et séquelles des traitements, des efforts collaboratifs internationaux ont permis le développement de protocoles thérapeutiques stratifiés sur les facteurs pronostiques majeurs incluant des facteurs biologiques tumoraux issus des analyses moléculaires et notamment génomiques. Cependant, si les traitements utilisés prennent de plus en plus en compte la biologie tumorale, leur adaptation aux facteurs individuels reste marginale. La thèse ici présentée cherche à mieux comprendre comment les caractéristiques tumorales et individuelles des patients modifient l’efficacité et la toxicité des thérapeutiques anticancéreuses utilisées en oncologie pédiatrique.Plusieurs travaux ont été réalisés :1- Etude de l’impact pronostique des facteurs tumoraux : évaluation de l’impact pronostique de la décroissance du marqueur tumoral alphafoetoprotéine (AFP) dans les tumeurs germinales malignes de l’enfant et de l’adolescent traitées par chimiothérapie ; 2- Etude de l’impact pronostique des facteurs constitutionnels : (i) évaluation de l’effet du sexe sur l’efficacité et la toxicité des agents alkylants ; (ii) évaluation de l’impact pronostique de polymorphismes génétiques de gènes impliqués dans le métabolisme du méthotrexate sur l’efficacité et/ou la toxicité du méthotrexate haute dose dans le traitement de l’ostéosarcome ;3- Etude des facteurs de risque de toxicité tardive : analyse de la de toxicité auditive sévère dans la cohorte des survivants à long terme de cancers pédiatriques (FCCSS)Therapeutic advances in pediatric oncology have improved survival rates reaching over 80%. In order to increase cure rates and decrease complications and treatment sequelae, international collaborative efforts led to the development of therapeutic trials stratified on major prognostic factors including biological factors. However, treatment adaptation to individual patient characteristics remains marginal.In this thesis, our objective was to better understand how somatic (tumor-related) and constitutional (patient-related) characteristics could modify efficacy and toxicity of anticancer therapies used in pediatric oncology. Several works were performed: 1- Prognostic analysis of tumor markers: assessment of the alpha-foetoprotéine (AFP) decline prognostic value in childhood malignant germ cell tumors; 2- Prognostic analysis of constitutional factors: (i) assessment of the interaction between gender and type of alkylating agents on efficacy and acute toxicity; (ii) assessment of the efficacy and toxicity impact of genetic polymorphisms in patients with osteosarcoma treated with high-dose methotrexate; 3- Risk factors analysis of long-term toxicities: analysis of severe ototoxicity in the French Childhood Cancer Survivors Study (FCCSS)
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Druaux, Fabrice. "Etude de la relation entre la cristallisation et l'évolution du magnétisme dans des couches minces désordonnées Ni-Ag riches en Ag." Rouen, 1986. http://www.theses.fr/1986ROUES039.
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Evolution du magnétisme et de l'effet Hall dans les alliages Ni(x)Ag(1-x) riches en argent obtenus dans un état désordonné puis cristallisés par recuit. Polarisation magnétique, susceptibilité en champ fort et coefficients de Hall. Interprétation des résultats par des considérations de structure
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Barilero, Gilles. "Etude de quelques proprietes magnetooptiques et magnetiques des semiconducteurs semimagnetiques zn : :(1-x)mn::(x)te et hg::(1-x)mn::(x)te." Paris 6, 1987. http://www.theses.fr/1987PA066084.
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L'effet d'echange entre les electrons de bande et les electrons d des ions manganese modifie les produits electroniques des alliages de zn dans un champ magnetique. L'effet zeeman de l'exciton permet de determiner la valeur des integrales d'echange de la bande de valence et de la bande de conduction dans ces composes. La presence d'interactions magnetiques entre les ions manganese est responsable des proprietes magnetiques. Les courbes d'aimantation des alliages dilues pour x5% en champ intense, a basse temperature, permettent de determiner la constante d'echange entre ions mn 1er voisins. Les alliages concentres presentent une phase de verre spin a basse temperature
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Griveau, Jean-Christophe. "Etude de composés fermions lourds supraconducteurs sous hautes pressions : CECU2SI2 et UPD2AL3." Université Joseph Fourier (Grenoble), 1998. http://www.theses.fr/1998GRE10252.
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L'objet de cette these est l'etude des composes fermions lourds supraconducteurs cecu#2si#2 et upd#2al#3 sous pression dans leur phase normale et supraconductrice par resistivite electrique (p#a#c) et par susceptibilite magnetique alternative (#a#c). Les mesures ont ete effectuees en conditions quasi-hydrostatiques (steatite) et hydrostatiques (#4he). Les mesures par resistivite electrique se sont effectuees sous champ magnetique : un diagramme hc#2(t) a ete etabli sous pression pour les deux composes. Pour cecu#2si#2, l'etude sur monocristal en resistivite electrique sous champ magnetique et sous pression (b,t)#- a montre une augmentation drastique du champ critique dans le regime ii avec hc#2(o)5 t contre 2,1 t a pression nulle. Les ajustements du champ critique dans un modele de supraconducteur en limite propre et couplage faible indiquent une anisotropie liee sans doute a la surface de fermi non spherique (coefficient gyromagnetique <1) tandis que ceux en limite sale et couplage fort indiquent une changement de comportement net entre les regimes i et ii. La pente varie fortement sous pression : 25 k/t dans le regime i et 12 k/t dans le regime ii. Pour upd#2al#3, une etude en susceptibilite magnetique sous pression #a#c- sur polycristaux caracterises en transport a permis d'etablir : un diagramme t#c(p) montrant une forte diminution de la supraconductivite apres 6 gpa. On constate en resistivite sous champ et sous pression le maintient du regime de liquide de fermi. On constate peu de variation du champ critique sous pression : la masse effective liee a la pente a t#c presente un faible maximum autour de 5 gpa avant de diminuer fortement a partir de 6 gpa. Ces deux composes presentent deux aspects de l'interaction entre supraconductivite non conventionnelle et magnetisme : competition pour cecu#2si#2 et coexistence pour upd#2al#3.
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Rekik, Mahmoud. "Mesure et modélisation du comportement magnéto-mécanique dissipatif des matériaux ferromagnétiques à haute limite élastique sous chargement multiaxial." Thesis, Cachan, Ecole normale supérieure, 2014. http://www.theses.fr/2014DENS0019/document.
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Les travaux de recherche discutés dans ce manuscrit concernent la conception des générateurs de puissance électrique pour l'aéronautique. L’augmentation de la puissance massique de ces équipements passe par une augmentation des vitesses de rotation, donc une augmentation des contraintes. Un premier point est de s'assurer de la bonne tenue mécanique des matériaux. Un deuxième point est de pouvoir prendre en compte les modifications du comportement magnétique (et donc in fine du couple) lorsqu'ils sont soumis à un état de contraintes multiaxial. L’étude présentée vise en particulier à illustrer l’influence d'états de contraintes biaxiaux sur le comportement magnétique des matériaux constitutifs du rotor. Le défi repose sur la mise en place de méthodes de caractérisation du comportement magnéto-mécanique dissipatif uniaxial et multiaxial des nuances développées par Aperam et utilisées par Thales Avionics pour leurs applications aéronautiques (en FeCo-2V et Fe-3%Si à grains non orientés). Des essais non conventionnels seront effectués sur des échantillons en forme de croix de manière à s'approcher des contraintes réellement subies par le rotor. Les essais sont effectués sur la machine d'essai triaxiale Astrée du LMT-Cachan. L'état de contraintes est estimé par corrélation d'images et par diffraction des rayons X. Des mesures magnétiques anhystérétiques et de pertes d'énergie sous contraintes sont reportées. D'autre part, un modèle multi-échelle multiaxial, décrivant le comportement d’un VER à partir de l'équilibre énergétique à l'échelle microscopique sera présenté. L’approche est fondée sur la comparaison des énergies libres de chaque domaine. Une comparaison probabiliste est faite pour déterminer les variables internes que sont les fractions volumiques des domaines. Différentes stratégies envisageables pour modéliser la dissipation statique seront discutées. Puis nous présentons l’approche magnéto-élastique que nous avons retenue visant à une meilleure considération de l’effet de la contrainte sur le comportement des matériaux ferromagnétiquesThe research presented in this thesis is motivated by the design of rotors for high speed rotating machines. The increased power density of these devices requires a higher rotation speed, leading to higher levels of centrifugal forces and stress in the rotor. A first point is to ensure good mechanical strength of the materials. A second point is to take into account changes in the magnetic behavior (and ultimately torque) when they are subjected to a multiaxial stress state. The present study aims at exploring the influence of biaxial stress states on the magnetic behavior of the materials of the rotor. The challenge lies in the development of methods for the characterization of the magneto-mechanical dissipative uniaxial and multiaxial behavior of metal sheets developed by Aperam Alloy and used by Thales Avionics for their aeronautical applications (in FeCo-2V and non-oriented Fe-3%Si). Non conventional experiments are performed on cross-shaped samples in order to apply biaxial stress representative of the loadings experienced by rotors of rotating machines. These experiments are performed on a multiaxial testing machine, Astrée. Stress level is estimated thanks to digital image correlation and X-ray diffraction Both anhysteretic and dissipative magnetic responses to magneto-mechanical loadings have been recorded. On the other hand, a multi-scale multiaxial model describing the behavior of a RVE from the energy balance at the microscopic scale is presented. The approach is based on a comparison of the free energy of each domain. A probabilistic comparison is made to determine the volume fraction of domains used as internal variables. Different strategies for modeling the static dissipation are discussed. Then we present the chosen magneto-elastic approach, improving the description of the effect of stress on ferromagnetic materials behavior
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Opagiste, Christine. "Synthèse et étude des propriétés magnétiques des composés supraconducteurs surdopés à base de thallium." Université Joseph Fourier (Grenoble), 1994. http://www.theses.fr/1994GRE10097.
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Cette etude sur les composes supraconducteurs surdopes tl#2ba#2cuo#6##d et tl#2ba#2cacu#2o#8##d concerne leurs syntheses, structures et proprietes magnetiques dans l'etat normal et supraconducteur. La synthese effectuee sous haute pression (100 bar d'oxygene, helium, argon) et a partir du precurseur tl#2ba#2o#5, permet d'eviter les pertes de thallium et la formation de bacuo#2. Concernant la phase tl#2ba#2cuo#6##d, le diagramme de phase (diagramme iso-t#c) a ete etabli dans le plan t#r#e#c#u#i#t, p(o#2). Donnant acces au domaine surdope (t#c variant de 92 a ok), il nous a permis d'etudier les differents domaines de stabilite des deux structures cristallographiques existant pour ce compose. Nous en avons deduit que la structure orthorhombique etait stoechiometrique en cations, alors que la structure tetragonale pouvait presenter un deficit en thallium. De nettes correlations ont ete observees entre t#c et les parametres de mailles pour la phase tl#2ba#2cuo#6##d ainsi que pour la phase tl#2ba#2cacu#2o#8##d dont le surdopage en oxygene a ete realise au moment de la synthese sous un melange helium-oxygene. Les proprietes magnetiques ont ete etudiees par des mesures d'aimantation et de susceptibilite differentielle #'#h. Nous avons constate que la fraction meissner augmentait avec t#c, et que le domaine de reversibilite etait plus etendu pour les echantillons presentant une t#c proche de t#c maximale. Ces observations sont a relier avec la diminution de l'anisotropie de ce systeme avec le surdopage. Dans le domaine reversible, la phase mixte est tres affectee par les fluctuations thermiques autour de t#c. L'analyse des mesures de m(h,t) et de #'#h a permis de suivre l'evolution de #a#b(t) avec t#c. Les resultats obtenus montrent que le compose de dopage optimal (t#c maximale) se comporte comme un supraconducteur de type b. C. S. Le surdopage conduit a un comportement de #a#b(t) difficilement conciliale avec les modeles standards (b. C. S. , deux fluides). Par ailleurs, #a#b(o) obtenue par extrapolation semble peu sensible au surdopage
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Billon, Bertrand. "Etude microcalorimétrique et magnétique du diagramme de phase des composés YBa2Cu3O(7-(delta)) et HgBa2CuO(4+(delta)." Université Joseph Fourier (Grenoble), 1998. http://www.theses.fr/1998GRE10132.
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La penetration du champ magnetique dans les supraconducteurs de type ii sous forme de vortex donne lieu, dans le cas particuler des supraconducteurs a haute temperature critique, a l'existence demultiples etats (liquide, solide, verre) de cette nouvelle matiere : la matiere vortex. L'etude de ces differents etats et des transitions entre eux constitue le but principal de cette these. Pour y parvenir, nous avons developpe deux dispositifs experimentaux adaptes a la mesure de tres petits echantillons (quelques microgrammes) : un microcalorimetre et un susceptometre a sonde de hall. Les excellentes performances de ces appareils de mesure ainsi que l'association de la chaleur specifique et de la susceptibilite alternative conduisent a des resultats nouveaux et originaux notamment au niveau de l'evolution du systeme tout au long de la ligne de fusion du solide de vortex. Notre travail concerne essentiellement le compose supraconducteur yba#2cu#3o#7## pour lequel nous avons montre que la fusion du reseau de vortex etait une transition du premier ordre dans certaines conditions. Ces conditions contribuent a la definition d'un critere universel traduisant le changement d'ordre de la transition. Ce critere permet ensuite de definir deux nouveaux points critiques du diagramme de phase (h,t). Enfin, nous avons ebauche la meme etude sur le compose supraconducteur plus recent hgba#2cuo#4#+#.
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Gautier, Eric. "Etude des propriétés structurales et physiques de la famille d'oxycarbonates supraconducteurs (Cu,C)Ba2Ca(n-1)CunOy." Université Joseph Fourier (Grenoble), 1997. http://www.theses.fr/1997GRE10281.
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Parmi les nouveaux materiaux supraconducteurs a hautes temperatures critiques (tc) decouverts ces dernieres annees, les cuprocarbonates de formule generale (cu,c)ba#2ca#n#-#1cu#no#y presentent l'avantage d'avoir des tc tres elevees (jusqu'a 120 k) sans contenir de cations toxiques tels que bi, ti, ou hg. L'une de leurs caracteristiques est d'etre synthetises sous haute pression (8 gpa) et a haute temperature (1200c). La synthese des composes a ete optimisee, d'une part grace a un meilleur controle de la quantite de carbone, d'autre part a la prise en compte du taux d'oxydation du precurseur. Les substitutions cationiques (ca, >y et c, >n) ont ensuite ete etudiees ainsi que le role de la stoechiometrie en oxygene. Ceci a ete couple a l'etude des proprietes physiques par mesure de susceptibilite magnetique alternative et de resistivite sous pression. Le caractere surdope des echantillons apres synthese a pu etre mis en evidence. Les reductions ont permis d'atteindre le dopage optimal pour lequel tc=120k dans le terme (cu,c)ba#2ca#2cu#3o#y. La structure de ces composes suit le schema general des cuprates supraconducteurs avec des plans conducteurs (plan cuo#2) et des reservoirs de charges. La presence d'impuretes non identifiees n'a pas permis de determiner la structure en details a partir de donnees de diffraction des rayons x ou des neutrons. Il semble cependant que les plans cuo#2 externes soient un peu ondules du fait de la presence alternee de cu et c dans le reservoir de charges (plan de base). L'utilisation de techniques locales telles que la microscopie electronique couplee a l'analyse par spectroscopie eels ont permis de mettre en evidence la presence de groupement co#3 formant un arrangement alterne avec les atomes de cuivre dans le plan de base, l'existence d'un atome d'oxygene mobile entre deux atomes de cuivre dans ce meme plan, lui conferant un environnement plan carre comme dans yba#2cu#3o#7. Differents types de defauts tels qu'intercroissances de differents membres de la serie, absence locale de carbone sont apparus. Enfin, une determination structurale a l'echelle d'un cristallite (1 m) a ete abordee en utilisant les intensites mesurees sur les cliches de diffraction electronique, a l'aide d'une approche de type patterson.
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Cheaito, Bassam. "Contribution à l'étude de la supraconductivité anormale du composé EuMo6S8." Grenoble 1, 1986. http://www.theses.fr/1986GRE10100.
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Etude de monocristaux de eumo::(6)s::(8) et d'echantillons frittes de yb::(1,2-x)eu::(x)mo::(6)s::(8) basee sur des mesures de transport sous pression et sous champ magnetique, des mesures de la susceptibilite magnetique et des mesures rpe; mise au point d'un dispositif automatise de mesures de transport. Correlations entre la temperature de transition structurale, la remontee de la resistivite a basse temperature et la transition supraconductrice sous pression; effets de la composition des echantillons frittes. Mise en evidence d'une valeur tres elevee du coefficient de chaleur massique electronique. Discussion des proprietes anormales dans le cadre d'un modele de melange de phases triclinique et rhomboedrique et d'un modele de supraconductivite propre
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Almasri, Hanine. "Toxicologie des mélanges de pesticides chez des abeilles exposées à un agent pathogène : action combinée de l'agent pathogène Nosema ceranae, de l'insecticide imidaclopride, du fongicide difénoconazole et de l'herbicide glyphosate Mixtures of an insecticide, a fungicide and a herbicide induce high toxicities and systemic physiological disturbances in winter Apis mellifera honey bees Toxicity of the pesticides imidacloprid, difenoconazole and glyphosate alone and in binary and ternary mixtures to winter honey bees: effects on survival and antioxidative defenses Toxicological status changes the susceptibility of the honey bee Apis mellifera to a single fungicidal spray application Physiological effects of the interaction between Nosema ceranae and sequential and overlapping exposure to glyphosate and difenoconazole in the honey bee Apis mellifera." Thesis, Avignon, 2020. http://www.theses.fr/2020AVIG0722.
Full textAbstract:
Les données scientifiques actuelles suggèrent un déclin de la diversité et de l’abondance des insectes, y compris les abeilles domestiques Apis mellifera. Ces dernières sont confrontées à de fortes pertes de colonies dans plusieurs régions du monde telles que l’ouest de l’Europe et les États-Unis. De nombreuses études suggèrent que l’origine du déclin des colonies d’abeilles est multicausale et identifient les pesticides et les agents pathogènes comme étant les principaux contributeurs à ce déclin. La co-exposition des abeilles à de multiples pesticides et l’infection par plusieurs pathogènes constituent un phénomène courant. Cependant, les recherches sur les effets des mélanges de pesticides n’ont pas fait l’objet d’un intense développement. Ainsi, les travaux conduits dans le cadre de cette thèse ont été focalisés sur la détermination de la toxicité des mélanges de pesticides, appliqués à des niveaux d’exposition environnementaux, en présence d’un agent pathogène. Le choix s’est porté sur l’étude des interactions entre un insecticide néonicotinoïde, l’imidaclopride, un fongicide azole, le difénoconazole, et un herbicide, le glyphosate, en présence de l’agent pathogène Nosema ceranae. Les résultats des différentes études effectuées durant cette thèse, révèlent la complexité des études sur les mélanges de pesticides. Ces travaux nous ont permis de constater que les effets d’un mélange de pesticides peuvent fortement varier en fonction des concentrations des pesticides constituant le mélange. L’augmentation du nombre de substances et du niveau d’exposition, n’induit pas nécessairement une augmentation de la toxicité du mélange. De plus, les effets du mélange peuvent varier en fonction de la séquence d’exposition aux pesticides et de l’état sanitaire des abeilles. Les mélanges de pesticides affectent l’état physiologique des abeilles suite à une réponse systémique liée à des perturbations de mécanisme généraux tels que le stress oxydant. Cependant, ces trois pesticides, seuls et en mélanges n’ont aucun effet sur l’installation du microbiote intestinal à des niveaux d’exposition environnementauxCurrent scientific findings suggest a decline in the diversity and abundance of insects, including the honey bee Apis mellifera. The latter are facing high colony losses in several regions of the world such as Western Europe and the United States. Numerous studies suggest that the origin of bee colony decline is multi-causal and identify pesticides and pathogens as the main contributors to this decline. Co-exposure of honey bees to multiple pesticides and infection by multiple pathogens are common phenomena. However, research on the effects of pesticide mixtures has not been extensively developed. Thus, the thesis work has focused on determining the toxicity of pesticide mixtures, applied at environmental exposure levels, in the presence of pathogens. The choice was made to study the interactions between a neonicotinoid insecticide, imidacloprid, an azole fungicide, difenoconazole, and a herbicide, glyphosate, in the presence of the pathogen Nosema ceranae. The results of the different studies, carried out during this thesis, reveal the complexity of the studies on pesticide mixtures. The work allowed us to notice that the effects of a pesticide mixture can vary according to the concentrations of the pesticides constituting the mixture. The increase of the number of substances and the level of exposure does not necessarily induce an increase of the toxicity of the mixture. Furthermore, the effects of the mixture may vary depending on the sequence of exposure to the different pesticides and the health status of the honey bees. Pesticide mixtures affect the physiological state of individuals as a result of a systemic response related to disturbances of general mechanisms such as oxidative stress. However, these three pesticides, alone and in mixtures, have no effect on the installation of the intestinal microbiota at environmental exposure levels
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Thomas, Amandine. "Hypoxie intermittente et homéostasie glucidique : étude des mécanismes d'action cellulaire A hybrid model to study pathological mutations of the human ADP/ATP carriers Visceral white fat remodeling contributes to intermittent hypoxia-induced atherogenesis The insulin sensitizing effect of topiramate involves KATP channel activation in the central nervous system The Impact of Sleep Disorders on Glucose Metabolism: Endocrine and Molecular Mechanisms Endoplasmic reticulum stress as a novel inducer of hypoxia inducible factor-1 activity: its role in the susceptibility to myocardial ischemia-reperfusion induced by chronic intermittent hypoxia Chronic intermittent hypoxia improves whole-body glucose tolerance by activating skeletal muscle AMP-activated protein kinase in mice Prolyl-4-hydroxylase 1 (PHD1) deficiency impairs whole-body glucose tolerance and insulin sensitivity in mice but does not worsen high-fat diet-induced metabolic dysfunctions Specific transcriptomic signature in response to intermittent hypoxia exposure in liver and fat tissue." Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GREAV044.
Full textAbstract:
L'hypoxie intermittente (HI), induite par les apnées du sommeil, conduit à des altérations de la sensibilité à l'insuline et de l'homéostasie glucidique mais les mécanismes impliqués restent mal connus. L'objectif de ce travail était d'étudier les effets et les mécanismes sous jacents d'une exposition chronique à l'HI sur l'homéostasie glucidique. L'HI induit une résistance à l'insuline à la fois systémique et tissulaire, ainsi qu'une amélioration de la tolérance au glucose associée à une activation de l'AMPK musculaire. L'HI cause également des altérations du foie et du tissu adipeux associées à un changement du pattern d'expression des gènes dans ces tissus et à un risque accru de développement de pathologies vasculaires comme l'athérosclérose. Enfin, la délétion de PHD1, une des protéines régulatrices de HIF-1, entraîne une résistance à l'insuline associée une stéatose hépatique, faisant de HIF-1 une cible potentielle impliquée dans les altérations metaboliques induites par l'HIIntermittent hypoxia (IH), induced by sleep apnea, leads to alterations in insulin sensitivity and glucose homeostasis but the mechanisms involved remains poorly understood. The objective of this work was to study the effects and the underlying mechanisms of chronic exposure to IH on glucose homeostasis. IH induces both systemic and tissue-specific insulin resistance , as well as improved glucose tolerance associated with an activation of muscle AMPK. IH also causes a change in the pattern of gene expression in liver and adipose tissue and an increased risk of vascular pathologies such as atherosclerosis development. Finally, the deletion of PHD1, a regulatory protein of HIF-1, leads to insulin resistance associated with hepatic steatosis, making HIF-1 a possible target involved in the metabolic changes induced by IH