In intraplate seismic zones (e.g. the New Madrid Seismic Zone, NMSZ, in the southcentral United States), the source of stress that drives earthquake is very complex. Data from the NMSZ indicate 3 earthquake of magnitude M~7, occurring at an approximate interval of 500 years during the last 2000 years. One hypothesis that satisfies these conditions proposes that short-lived bursts of earthquakes may result from perturbations in the local or regional stress field. This causes relaxation of a lower crustal weak zone which drive repeated earthquakes. The number of earthquakes is dependent on the geometry and rheology of the weak zone. Using finite element techniques which employ contact surfaces to model discrete faulting events and a maximum shear stress criteria evaluated at each node. We investigate the relevant parameter space, as it affects the concentration of stress at the base of the seismogenic fault and the number of earthquakes generated over a given time interval. Parameters that can be varied include earthquake stress drop, background tectonic stress, and maximum shear stress at failure. Results show that solutions are non-unique. With the addition of existing observational evidence, however, we can place bounds on the range of parameters which satisfy above observations.

Haynes alloy 282 is a new gamma prime (γ’) precipitation strengthened nickel-base superalloy developed for high temperature applications in land-based and aero turbine engines. Joining is a crucial process both during the manufacturing of new components and repair of service-damaged turbine parts. Unfortunately, the new superalloy cracks during laser beam welding (LBW), which is an attractive technique for joining superalloys components due to its low heat input characteristic that preclude the geometrical distortion of welded components. This research is therefore initiated with the goal of studying and developing an effective approach for preventing or minimizing cracking during LBW of the new superalloy Haynes 282. Careful and detailed electron microscopy and spectroscopy study reveal, for the first time, the formation of sub-micron grain boundary M5B3 particles, in the material. Microstructural study of welded specimens coupled with Gleeble thermo-mechanical physical simulations shows that the primary cause of weld heat affected zone (HAZ) cracking in the alloy is the sub-solidus liquation reaction of intergranular M5B3 borides in the material. Further weldability study showed that the HAZ liquation cracking problem worsens with reduction in welding heat input, which is normally necessary to produce the desired weld geometry with minimum distortion. In order to minimize the HAZ cracking during low heat input laser welding, microstructural modification of the alloy by heat treatment at 1080 - 1100oC has been developed. The pre-weld heat treatment minimizes cracking in the alloy by reducing the volume fraction of the newly identified M5B3 borides, while also minimizing non-equilibrium grain boundary segregation of boron liberated during dissociation of the boride particles. Further improvement in resistance to cracking was produced by subjecting the material to thermo-mechanically induced grain refinement coupled with a pre-weld heat treatment at 1080oC. This approach produces, for the first time, crack-free welds in this superalloy, and the benefit of this procedure in preventing weld cracking in the new material is preserved after post-weld heat treatment (PWHT), as additional cracking was not observed in welded specimens subjected to PWHT.

Härdighet för vedartade växter förknippas oftast med zonkartans zonangivelser. Det är dock inte enbart härdighetsiffran som bestämmer om en växt är härdig eller inte. Klimatet på platsen är en avgörande faktor för hur en växt klarar sig eller inte.  Via en enkät tog jag reda på vad odlare i Norr- och Västerbottens län tycker om zonkartan och hur de använder sig av den när de väljer vedartat växtmaterial. Nästan alla odlare ställer sig positiva till zonkartans zonangivelser. De påpekade dock brister med användandet av den då den inte tar hänsyn till växtens proveniens, lokalt klimat eller växters krav på odlingsplats vilket är viktiga faktorer som påverkar härdigheten hos växten. Odlarna efterlyste mer information om växternas krav på sin odlingsplats och hur man skapar ett mikroklimat för just den växten i samband med zonangivelsen för växten.  En växtlista med växter som anges med en lägre zonangivelse än den zon den odlas i har skapats utifrån odlarnas egna erfarenheter. Med hjälp av litteraturstudien och odlarnas åsikter har jag skapat ett förlag på hur en komplettering av zonkartan skulle kunna se ut för att förbättra både kunskapen om det lokala klimatet och utöka växtvalen för odling i Norrland. / The hardiness of a plant is often strongly associated with the recommendations on the climate zone map. However, it is not only the climate zone recommendation that determines whether a plant is cold hardy enough to survive and thrive at a certain location.  By sending a questionnaire to local growers in northernmost Sweden I wanted to investigate how the climate zone map is used and how well it works in the northern part of Sweden. Most growers were positive to the recommendations in the map. However, they pointed out that the climate zone map does not take into account the genetic heritage, the local microclimate and the requirements of the location on which the plant is supposed to grow, which are all very important. Growers mentioned that more information about how to create a good micro climate for a certain plant in a certain zone would be very useful. From the questionnaire I have put together a list of plants that growers in northern Sweden have grown outside the recommendation from the climate zone map. And by using information from the growers together with information from my literature study I have created a suggestion on an updated climate zone map to see if it is possible to raise knowledge and increase plant selection in northernmost Sweden.

Univ., Diss.--Freiburg im Breisgau, 2000.

Univ., Diss.--Jena, 2001.

Thesis (M.R.M.)--Simon Fraser University, 2001. / Includes bibliographical references (leaves 112-116).

Thesis (Ph.D.)--University of Delaware, 2005 . / Principal faculty advisor: Biliana Cicin-Sain, College of Marine Studies. Includes bibliographical references.

Si, pour les matériaux composites élaborés, de nombreuses études expérimentales ainsi que des modèles locaux de comportement ont été développés, la maîtrise du comportement des interfaces entre couches de surface ou d’assise de chaussées est actuellement un réel verrou scientifique. La méthode de dimensionnement française actuelle ne prend en compte, aux interfaces, que des conditions conventionnelles de collage ou de glissement parfait. Afin d’appréhender le comportement local de l’interphase\interface, les outils de la photomécanique apparaissent incontournables. La présente thèse propose une modélisation de l’interface rugueuse et endommageable par un modèle de zone cohésive en mode mixte. Ce manuscrit de thèse comporte trois chapitres. D’abord, le chapitre I présente un état de l’art sur les interfaces dans les matériaux et les structures et en particulier dans les couches de chaussées. Ensuite dans le chapitre II, une identification expérimentale des paramètres mécaniques et géométriques du modèle d’interface est proposée à travers des essais de traction et de cisaillement et des mesures de la texture (PMT et projections de franges). Les résultats obtenus (adhésion, rugosité,…) seront les paramètres d’entrée d’un modèle d’endommagement d’interface. Enfin, le chapitre III aborde la modélisation des interfaces entre couches de chaussées sous l’angle des modèles de zones cohésives avec la prise en compte de la rugosité géométrique. A l’issu de cette étude, une loi est proposée permettant de prendre en compte l’effet de la rugosité à une échelle locale dans une interface lisse équivalente à l’échelle globale. / Interface between bituminous layers is an important parameter for the pavement computational design.New pathologies in pavement structure require today rational methods taking into account theinterfaces behavior. Due to these concerns, the current study is based on a damage cohesive zonemodel (CZM) in mixed mode of the rough interfaces. The model was initially proposed by Allix-Ladevèze. This thesis presents a comprehensive interface modeling including delay effect, based ondamage energy release rate. The process of the present study is presented in three chapters. The firstchapter present the stat of art of interfaces. The second devoted to identify the parameters of theinterface model and material properties through advanced optical method as Digital Image Correlation(DIC) and (H-DIC). In the third chapter, a study of the influence of the elastic normal and tangentialstiffness and coupling parameters in the mixed mode on the debonding interfacial energy is presented.An analytical model provides relations between the interfaces stiffness, the coupling parameter of theCZM and the interfacial roughness. Then, a parametric numerical analysis is conducted to study theroughness effect on the interface constitutive law. Results show clearly the roughness influence in thiskind of structures. The damage behaviours predicted by the proposed model for pure mode I, puremode II and for mixed mode with taking into account of roughness are found in good agreement withexperimental results.

A fusão zonal compreende uma família de métodos para controle e distribuição de impurezas na qual uma pequena zona fundida é deslocada lentamente ao longo de um material sólido, redistribuindo o soluto. Ela é utilizada na purificação de materiais, num processo denominado refino zonal, mas também pode ser usada na distribuição homogênea ou descontínua de impurezas e no crescimento de cristais. A fusão zonal aplicada ao crescimento de grãos, visando a obtenção de materiais mono ou policristalinos com grãos grosseiros é denominada recristalização por fusão zonal (ZMR) e seu uso principal é na preparação de materiais para fabricação de dispositivos eletrônicos e fotovoltaicos, especialmente em silício. Na última década, o progresso na tecnologia ZMR foi feito principalmente em três campos: desenvolvimento de equipamento, controle de processo e modelagem numérica, mas somente algumas pesquisas abordam a fusão zonal a baixas temperaturas e restringem a aplicação do método a outros materiais semicondutores como os elementos do grupo III, IV ou V. Deste modo, o presente trabalho tem como objetivo verificar a influência da velocidade de varredura, da largura da zona fundida e do número de passadas no processo de fusão zonal de materiais de baixo ponto de fusão, em relação à obtenção de materiais policristalinos com grãos grosseiros. Para tanto, construiu-se um equipamento de fusão zonal horizontal e barras de alumínio puro (P0610) foram submetidas ao processo, variando os parâmetros acima referidos. A macroestrutura das amostras foi analisada e os resultados obtidos do número de grãos/área foram interpretados, verificando a influência dos parâmetros físicos anteriormente citados, do gradiente térmico e do super-resfriamento constitucional. Verificou-se que a redução na velocidade de varredura e na largura da zona fundida, de modo geral, mostrou-se eficiente em relação à diminuição do número de grãos por área. Os resultados obtidos indicam que a fusão zonal foi efetiva na obtenção de alumínio policristalino com grãos grosseiros e colaboram para melhorar a compreensão do processo. / The zone melting comprises a family of methods to control and to distribute impurities in which a small molten zone is moved slowly along a solid material, redistributing solute. It is used in materials purification, in a so-called zone refining process, but can also be used in homogeneous or discontinuous distribution of impurities and crystal growth. The zone melting applied to grain enlargement, leading to attain singlecrystalline or polycrystalline materials with coarse grains is so-called zone melting recrystallization (ZMR) and its major use is the preparation of materials for electronic and photovoltaic devices process especially silicon. In the last decade, progress in ZMR technology was done mainly in three areas: equipment development, process control, and numerical modeling, but only a few researches handle on zone melting at low temperatures and it limits the application of the method to other semiconductor materials such as III, IV or V group elements. Thus, this study aims to examine the influence of scan rate, zone width and the number of zone passes in the zone melting process of low melting point materials about getting polycrystalline materials with coarse grains. For this, horizontal zone melting equipment was built and pure aluminum bars (P0610) were zone melted, varying the parameters mentioned above. The macrostructure of the samples was analyzed and the results of the number of grains per area were assessed by checking the influence of physical parameters previously mentioned and the thermal gradient and the constitutional supercooling. It was found that scan rate and zone width reduction in general, proved to be efficient in reducing the number of grains per area. The results indicate that the zone melting was effective in obtaining aluminum polycrystalline coarse-grained and collaborate to improve the understanding of the process.

ANDRADE, Maria Amália Simonetti Gomes de. Crianças à sombra do conceito: perfil conceitual de gravidade. 2014. 126f. .– Tese (Doutorado) Universidade Federal do Ceará, Programa de Pós-graduação em Educação Brasileira, Fortaleza (CE), 2014. / Submitted by Gustavo Daher (gdaherufc@hotmail.com) on 2017-05-26T11:38:51Z No. of bitstreams: 1 2014_tese_masgandrade.pdf: 1319881 bytes, checksum: 8d26b303caa7dcb4990874f9dc954f8d (MD5) / Approved for entry into archive by Márcia Araújo (marcia_m_bezerra@yahoo.com.br) on 2017-05-26T11:46:19Z (GMT) No. of bitstreams: 1 2014_tese_masgandrade.pdf: 1319881 bytes, checksum: 8d26b303caa7dcb4990874f9dc954f8d (MD5) / Made available in DSpace on 2017-05-26T11:46:19Z (GMT). No. of bitstreams: 1 2014_tese_masgandrade.pdf: 1319881 bytes, checksum: 8d26b303caa7dcb4990874f9dc954f8d (MD5) Previous issue date: 2014 / This study aimed to provide a conceptual profile of gravity with conceptions of gravity of children four and five years old. The approach of conceptual profiles was adopted as a theoretical and methodological tool for analyzing the heterogeneity of ways of thinking and talking about this concept. This approach, designed by Mortimer (2000) and developed by a group of researchers in the research program of conceptual profiles, has already been used in several studies, dissertations and theses in Brazil and other countries. The conceptual profile of this study consisted of three genetic domains: the sociocultural domain, through a literature review on the history of the concept of gravity; the ontogenetic, through the compilation of studies on student conceptions of gravity; and the microgenetic, through an exploratory case study conducted with children four and five years old to grasp their conceptualizations of gravity. The dialogic analysis of discourses of children about why things fall provided a proposition of a conceptual profile of gravity, consisting in three zones: internalist, externalist and compositional. These three zones represent ways of children understanding about the concept of gravity. The internalist zone exposes that gravity is a characteristic of the body; externalist zone exposes that gravity is caused by an external action to the body; compositional zone shows that gravity is an exchange of actions. / Este estudo teve como objetivo principal constituir um perfil conceitual de gravidade com concepções de gravidade de crianças de quatro e cinco anos de idade. A abordagem de perfis conceituais foi adotada como ferramenta teórico-metodológica de análise da heterogeneidade dos modos de pensar e falar esse conceito. Essa abordagem, concebida por Mortimer (2000) e desenvolvida por um grupo de pesquisadores no programa de pesquisa de perfis conceituais, já foi empregada em várias pesquisas, dissertações e teses no Brasil e em outros países. O perfil conceitual deste estudo foi constituído em três domínios genéticos: o domínio sociocultural, por meio de uma revisão bibliográfica sobre a história do conceito de gravidade; o ontogenético, por meio da compilação de estudos sobre concepções de gravidade de estudantes; e o microgenético, por meio de um estudo de caso de natureza exploratória realizado com crianças de quatro e cinco anos de idade para apreender suas conceitualizações de gravidade. A análise dialógica dos discursos das crianças sobre o porquê de coisas caírem possibilitou uma proposição de perfil conceitual de gravidade, constituído em quatro zonas: internalista, externalista, composicional. Essas quatro zonas representam modos de compreensão das crianças sobre o conceito de gravidade. A zona internalista expõe que a gravidade é característica do corpo; a zona externalista que a gravidade é provocada por uma ação externa ao corpo; a zona composicional mostra que a gravidade é intercambio de ações.