Les alliages de zirconium sont utilisés notamment dans les assemblages de combustible nucléaire pour leur transparence aux neutrons ainsi que pour leur tenue mécanique et leur résistance à la corrosion. La connaissance de leur microstructure et de son évolution est nécessaire pour maîtriser les différents traitements thermomécaniques de la gamme de transformation qui comporte plusieurs trempes depuis le domaine bêta. Cette microstructure présente, à l’issue d’une trempe, des lamelles dites de Widmanstätten. Ces dernières soit se disposent parallèlement entre elles (platelets parallèles), soit se croisent en vannerie. Ces morphologies jouent sur l’étape suivante de filage ; en effet, les platelets parallèles défavorisent la fragmentation des lamelles. Une méthode a été mise en place pour quantifier ces morphologies.Lors de la transformation bêta vers alpha, un grain peut générer 12 orientations alpha (variants). Les paramètres qui influencent leur sélection sont encore peu connus. Le modèle proposé minimise la déformation moyenne lors de la transformation. D’abord analytique, il a été ensuite implémenté numériquement afin d’aborder des effets tels que la relaxation d’Eshelby, l’anisotropie élastique, une contrainte extérieure ou le voisinage. En parallèle, la sélection expérimentale a été quantifiée au moyen original de l’EBSD et des fractions des variants locales dans un ex-grain bêta. La confrontation des résultats expérimentaux avec le modèle a permis de le valider en partie et de déterminer la contrainte de trempe à la surface des éprouvettes ainsi que son effet sur la sélection de variants. / Zirconium alloys are frequently used in nuclear fuel assemblies. They are chosen for their low neutron absorption, their mechanical properties and their corrosion resistance. A better understanding of the microstructure evolution of these alloys should allow a better control of their process of fabrication. During processing, several quenches, from the beta to the alpha domain take place. The resulting microstructures are lamellar and are called Widmanstätten microstructures. These lamellae are either disposed in parallel or in crisscross and are named “parallel platelets” and “basketweaves”, respectively. These various morphologies have a significant impact on the extrusion; basketweaves facilitate grain fragmentation unlike parallel platelets. In this thesis project, a methodology was developed in order to quantify these morphologies.During the phase transformation, one beta grain can generate 12 different orientations of new alpha grains. The parameters which can influence variants selection are not yet well-known. The model proposed in the present study is based on the minimization of the mean elastic energy of the system during the phase transformation. First results were obtained analytically. Then, additional effects such as the Eshelby relaxation, the elastic anisotropy and the external strain were implemented numerically. In parallel, each alpha variant was quantified within a former beta grain by EBSD analysis. The comparison between the model and the experiments helped to partially validate the model as well as determine the quench strain on the surface of the sample. It was then possible to study the effect of quench strain on the variant selection.

Twenty first century manufacturing is characterized by customer specific products. Customers expect greater differentiation in the products that companies offer to them, thus changing the whole landscape of production. Greater the variety of products being offered to customers, greater is the complexity of shop floor operations. This complexity is translated to all the operations in the shop floor including material handling and inventory control. To overcome this situation, many manufacturers have turned to “Lean Manufacturing” to gain a competitive edge in the market by reducing costs and improving productivity in all operations throughout the shop floor. Therefore, this purpose of this thesis is to analyze the material handling of a highly customized multi-variant product-based production system. The thesis represents a case study that was done at a caravan manufacturing company in Tenhult, Sweden. During the study, data was gathered from field notes, observations and multiple semi-structured interviews. The findings were analyzed with respect to a theoretical background which was generated through an extensive literature review that was carried out throughout the research. Our analysis was based on a systems approach where the findings were categorized into three dimensions that affect material handling and inventory control. These dimensions are warehouse management systems, culture, and production management, which contribute to successful implementation of lean into the material handling operations and inventory control. In conclusion, the results show that efficient material handling and inventory control can only be achieved by finding a synergy between technology, people and organization. Our results also show that soft issues like organizational culture and employee culture need to be addressed along with technological issues because only when an alignment between people, technology and business objectives and values is achieved, lean implementation can be successful. Our results also show the need for better supplier customer collaboration to reduce inventory levels and material handling operation.

The evolutionary relevance of homeotic alterations for the origin of new taxonomic entities is still a controversial objective in plant sciences. In this context, the discovery of a floral homeotic variant of Capsella bursa-pastoris in natural populations offers the unique opportunity to elucidate the evolutionary significance of homeotic mutants in the wild. Since all petals are transformed into additional stamens, the variant was termed Stamenoid petals (Spe). In this thesis, a combination of ecological and molecular characterisation of the variant was performed, to improve the understanding of evolutionary processes in plant populations. Molecular markers were used to analyze genetic differentiation among known provenances and also within a large sympatric population of wild-type and homeotic mutant. The results clearly suggest a repeated evolution of the novel flower morphology. Furthermore, genetic analyses provided substantial evidence, that the two floral variants are well-defined into flower-type dependent sub-samples within one population. The evaluation of phenotypic traits elucidated that the homeotic variant is not hampered in fitness. In greenhouse and field experiments, a significant ecological differentiation in the onset of flowering was detected among variants. Finally, the novel floral phenotype shows a co-dominant inheritance, and a marker-assisted mapping approach exposed a single locus in a genetic map. In conclusion, the comprehensive study of ecological and molecular aspects indicates that the floral homeotic variant may be treated as an established taxonomic entity and proved the predicted role as model for evolutionary objectives. Since morphological alterations like Spe are discussed as a result of macroevolution, the homeotic variant of C. bursa-pastoris provides the opportunity to survey a (macro)evolutionary novelty in association with continuous micro-evolutionary adaptation

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第20989号 / 医博第4335号 / 新制||医||1027(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 朝長 啓造, 教授 松田 文彦, 教授 小柳 義夫 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

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This study explores the way imperfect information affects chess gameplay in players with different skill levels. To explore the effects of removing information from a perfect system we used both chess and a variant of chess known as dark chess or fog of war chess. With a sample size of eight players organised into four pairs, we gathered both quantitative data from the moves made in the chess matches and qualitative data from interviews with the participants. The findings of this research may be useful to chess enthusiasts and players who wish to study perfect and imperfect information systems in games, as well as game designers and game researchers who are studying the effects of hidden information on gameplay and strategy. Our findings show no relation between ratings and performance in dark chess but instead show a relation between strategies chosen by players and the outcome of dark chess games.

Pulmonary arterial hypertension (PAH) can be caused by pathogenic variants in the gene bone morphogenetic protein receptor 2 (BMPR2). While BMPR2 protein expression levels are known to be reduced in the lung tissue of heritable PAH (HPAH) patients, a systematic study evaluating expression in more easily accessible blood samples and its clinical relevance is lacking. Thus, we analyzed the BMPR2 mRNA expression in idiopathic/HPAH patients and healthy controls in blood by quantitative polymerase chain reaction and protein expression by enzyme-linked immunosorbent assay. Clinical parameters included right heart catherization, echocardiography, six-minute walking test and laboratory tests. BMPR2 variant-carriers (n = 23) showed significantly lower BMPR2 mRNA expression in comparison to non-carriers (n = 56) and healthy controls (n = 30; p < 0.0001). No difference in BMPR2 protein expression was detected. Lower BMPR2 mRNA expression correlated significantly with greater systolic pulmonary artery pressure and pulmonary vascular resistance. Higher BMPR2 mRNA expression correlated with greater glomerular filtration rate, cardiac index and six-minute walking distance. We demonstrated the feasibility to assess BMPR2 expression in blood and, for the first time, that BMPR2 mRNA expression levels are significantly reduced in variant carriers and correlated with clinical parameters. Further studies may evaluate the usefulness of BMPR2 mRNA expression in blood as a new marker for disease severity.

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Understanding microstructural evolution in Friction Stir Welding (FSW) of steels is essential in order to understand and optimize the process. Ferritic steels undergo an allotropic phase transformation. This makes microstructural evolution study very challenging. An approach based on Electron Backscattered Diffraction (EBSD) and phase transformation orientation relationships is introduced to reconstruct pre-transformed grain structure and texture. Reconstructed pre-transformed and post-transformed grain structures and textures were investigated in order to understand microstructural evolution. Texture results show that there is evidence of shear deformation as well as recrystallization in the reconstructed prior austenite. Room temperature ferrite exhibits well-defined shear deformation texture components. Shear deformation texture in the room temperature microstructure implies that FSW imposes deformation during and after the phase transformation. Prior austenite grain boundary analysis shows that variant selection is governed by interfacial energy. Variants that have near ideal BCC/FCC misorientation relative to their neighboring austenite and near zero misorientation relative to neighboring ferrite are selected. Selection of coinciding variants in transformed prior austenite Σ3 boundaries supports the interfacial-energy-controlled variant selection mechanism.