The purpose of this thesis is to improve predictions of irradiation hardening in metals with a focus on coarse-graining via meso-scale simulations. Increasing hardness and decreasing in ductility in nuclear reactor pressure vessel steel is the limiting factor of nuclear reactor life, and accurately predicting reactor life is of the utmost importance for the safe operation of nuclear facilities. This is an inherently multi-scale problem with primary damage occurring at the atomic scale and its effects propagating across ten orders of magnitude in length and time scale to changes in macroscopic material properties, which must be reflected in its methods of prediction. To achieve this goal, this thesis develops two novel approaches to simulate the motion of dislocations in irradiated alpha-iron. First, a dislocation dynamics simulation coarse-graining insight from atomistic dislocation-defect simulations is used to guide the selection of proposed constitutive models. Several studies investigating the effect of size distribution show that the mean defect size can be used with the selected models to predict material hardening without a complex treatment for the defect size distribution. The hardening effect of the commonly observed defect types are found independently and a superposition principle is proposed for materials with both defect types. Second, a link to transition state theory and thermally activated reactions is established using a new method augmenting a discrete dislocation dynamics simulations with the nudged elastic band method to characterise the minimum energy pathways of dislocation reactions. This development enables calculations of activation energy for dislocation events using a continuum method as well as the numerical calculations of dislocation attempt frequency. The thesis concludes with an extension to the analysis of coarse-graining unit events to large scale dislocation-obstacle bypass phenomena.

[pt] Este trabalho apresenta um estudo do escoamento num meio poroso com fronteira livre. Modela-se o escoamento através da Teoria Contínua de Misturas para um meio homogêneo, isotrópico, rígido, estacionário e saturado com fluido newtoniano incompressível, obtendo-se a equação diferencial que rege o fenômeno de percolação. Considera-se a geometria do meio poroso retangular e reformula-se o problema em desigualdade variacional Sobre domínio conhecido via transformada de Baiocchi, onde se elimina a necessidade de se saber a fronteira livre a priori. Discretiza-se o problema. pelo método de Galerkin e emprega-se o Métodos dos Elementos Finitos para aproximar o espaço de funções envolvido. Resolve-se o Problema Linear de Complementaridade utilizando um algoritmo baseado num Método de Continuação para Desigualdades Variacionais para encontrar a região de escoamento. / [en] In this work, the Steady flow of an incompressible Newtonian fluid in a homogeneous, isotropic, rigid and saturated media is modeled by using the Continuum Theory of Mixtures. Due to a Baiocchi transformation, the seepage problem for a rectangular porous media is rewritten as a variational inequality, for which the a priori knowledge of the free boundary is not necessary. A Galerkin procedure is employed for the discretization of the problem and the related function spaces are approximated by means of Finite Element Techniques. An algorithm based upon a Continuation Method for variational inequalities applied for the determination of the free boundary.

The continuum theory of large deformation elasto-plasticity is summarized as far as it is necessary for the numerical treatment with the Finite-Element-Method. Using the calculus of modern differential geometry and functional analysis, the fundamental equations are derived and the proof of most of them is shortly outlined. It was not our aim to give a contribution to the development of the theory, rather to show the theoretical background and the assumptions to be made in state of the art elasto-plasticity.

Kaohsiung is transforming from a city of heavy industries into one of service industries, the rate of unemployment and adjustment of industry structure are becoming the real challenges for local development. During WTO and the 2009 World Games, moreover, Kaohsiung is expected to rise to the challenge of risks. Meanwhile, demand of citizens in Kaohsiung are not fully corresponded to public policies made by central government, and most of the people don¡¦t care as much as should local affairs because of lack of effective communications between public and private sectors. Therefore, in city marketing efforts, it would be more important to encourage participation and integrate multiple sectors¡¦ opinions as ¡§internal marketing¡¨ rather than just trying to attract businesses to the city. An integrated public affair management(PAM) framework(Wang et al., 2003)is adopted to describe situations in the pluralistic societies. Then we introduce the Cognitive Continuum Theory(CCT) adopted by Hammond et al., (1987) and Interactive Management (IM) technique developed by Warfield (1994). Results of studies are: 1) the problems of Kaohsiung¡¦s local development on structure of industry, human resource and port of Kaohsiung, 2) in the CCT studies there exist quite a few differences of cognition and modes of cognition presented tend to ¡§intuition¡¨ or ¡§analysis¡¨ between limited information, and 3) the IM analysis include competitive strategies for Kaohsiung¡¦s local development and an problematique diagram to demonstrate the structure of strategies. The conclusion is that, although there exist diversities of opinions among multiple stakeholders in Kaohsiung, they can be quite effectively addressed with the IM technique. Methods and results introduced and used here should be of value to relevant agencies about public forum and citizen conference.

L’émergence de comportements collectifs cellulaires n’est pas bien comprise. Nous l’abordons dans deux systèmes biologiques. A l'échelle du micromètre lors de la constriction de l’anneau cytokinétique, nous montrons que des complexes d’acto-myosine s’auto-organisent sous forme d’agrégats dans la levure à fission et dans la cellule de mammifères. Ces auto-organisations découlent de règles d'interactions communes mais pour des fonctions distinctes, le transport et la génération de stress respectivement. A l'échelle de 100 micromètres, nous observons des pulsations corrélées de cellules épithéliales. Nous montrons les rôles du frottement avec la surface, et le couplage entre l’aire cellulaire, sa hauteur et sa contractilité. Nous présentons aussi deux études, des polyamines synthétiques pour étudier la polymérisation d'actine in vivo, puis l’inversion de sens dans la migration - la ratchetaxie. Cette thèse illustre l'importance des phénomènes physiques dans la dynamique cellulaire. / The emergence of collective behavior from the interaction of individual units is not clear. In this thesis, we address this question in two different systems at different scales. At the micrometer scale during cytokinetic ring constriction, we show that acto-myosin self-organizes into rotating and static clusters in fission yeast and mammalian cells. These self-organizations arise from common interaction rules, but to serve distinct functions, transport and stress generation respectively. At 100 micrometers scale, we report correlated pulsations of cells in an epithelial monolayer. We show the key roles of substrate friction, and the tight coupling between cell area, cell height and contractility. We also present two other studies: synthetic polyamines for studying actin polymerization in vivo, and direction reversal in single cell migration during ratchetaxis. Altogether, this PhD illustrates the importance of physical phenomena in cellular dynamics.

Title: Baire and Harmonic Functions Author: Petr Pošta Department: Department of Mathematical Analysis Supervisor: prof. RNDr. Jaroslav Lukeš, DrSc., Department of Mathematical Analysis Abstract: The present thesis consists of six research papers. The first four articles deal with topics related to potential theory, Baire-one functions and its important subclasses, in particular differences of semicontinuous functions. The first paper is devoted to the stability of the Dirichlet problem for which a new criterion in terms of Poisson equation is provided. The second paper improves the recent result obtained by Lukeš et al. It shows that the classical Dirichlet solution belongs to the B1/2 subclass of Baire-one functions. A generalization of this result to the abstract context of the Choquet theory on functions spaces is provided. Finally, an abstract Dirichlet problem for the boundary condition belonging to the class of differences of semincontinuous functions is discussed. The third paper concentrates on the Lusin-Menshov property and the approximation of Baire- one and finely continuous functions by differences of semicontinuous and finely continuous functions. It provides an exposition of topologies (various density topologies as well as the fine topologies in both linear and non-linear potential...

While the preservation and sharing of research data are two topics well researched, there is a need to better understand the connections between them, especially from a Swedish perspective. In relation to this, it is interesting to investigate how researchers themselves are involved in these processes – where and how they preserve their data, for what reasons, how they manage their data for preservation and sharing, and furthermore what consequences this might have for the archiving of research data. The method used in this thesis is semi-structured interviews with 10 researchers from various Swedish universities, conducted in person, via Zoom or by e-mail. The researchers were chosen from their sharing activities on research data repositories. The interviews were processed in Taguette, where the data was organized by tags. The tags with their related statements were then organized into themes. Furthermore, a theoretical analysis based on the records continuum model was conducted.  The primary reason that was stated for preservation was data sharing. The researchers expressed a wish for their research data to be reused, as well as stating reasons related to transparency. The researchers also expressed that their data management was influenced by future data sharing. One researcher had archived their data at the university, although most of the participants was positive to doing so in the future. It appears that the researchers in this study takes initiative when it comes to the preservation and sharing of their data. Most of the participants view the data repository as a good platform for preservation, possibly because such platforms can fulfil their reasons for participating in preservation activities. This is a two years master’s thesis in Archival Science.

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