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This thesis work is concerned with effect of material grade on fatigue strength of welded joints. Fatigue strength evaluation of welded joints in as welded and post weld treated condition was carried out with effective notch method. Results of peak stress method have also been compared with those of effective notch method for as welded joints. In addition, using the results of effective notch method, the effect of important weld and global geometry factors on notch stress concentration factor has been studied with 2-level design of experiment and a mathematical relation among stress concentration factor and the geometric factors has been proposed. Overall, thickness of the base plate and toe radius is found to be the most important factors determining fatigue strength of the joint. Welding induced residual stresses have also been predicted using 2D and 3D FEM analysis to see their effect on fatigue strength of the joints. Also, transversal residual stresses were measured using X-ray diffraction method to assess the accuracy of predicted results. Based on simulation results, effect of geometric factors on maximum value of transversal residual stress was also investigated.

Textural and compositional variations in titanite, along with whole-rock geochemistry, provide constraints on the emplacement and cooling histories of two plutons: the Jurassic Notch Peak pluton and the Oligocene Little Cottonwood stock, both in Utah. Titanite textures observed with back-scattered electron (BSE) imaging along with their compositions were used to determine four periods of growth: cores, rims, interstitial overgrowths, and secondary replacements. Brightness in BSE images correlates mostly with rare earth elements (REE). REE patterns in cores and rims are compositionally similar in both plutons, although the Notch Peak intrusion tend to be slightly more enriched in REE. Overgrowths and secondary replacements typically have lower concentrations of REE and Fe and higher Al, Mn, F, and U. They also have similar δ18O values to primary titanite, indicating alteration and recrystallization from exolved magmatic fluids rather than meteoric sources. In the Notch Peak intrusion, titanite grains usually have simple, oscillatory zoned textures that include cores which include bright sector zones. These are overprinted by secondary titanite that grows within and replaces the primary titanite grain. At some localities, Notch Peak titanites have been hydrothermally altered to fine-grained aggregates of rutile or brookite, magnetite, quartz, and plagioclase. These observations indicate a simple cooling path after magmatic intrusion, followed by hydrothermal alteration for the Notch Peak intrusion. The Little Cottonwood stock contains titanite grains that are distinctly different from those in the Notch Peak intrusion. They typically contain a distinct patchy core with rounded, resorbed ilmenite inclusions. Surrounding the core is a mantle of oscillatory zoned titanite. On many grains, narrow rims of secondary overgrowths are observed as well as interstitial titanite growing in between chloritized biotite sheets. The cores of these titanite grains suggest that a more reduced, ilmenite-rich magma mixed into an oxidized felsic magma, destabilizing existing ilmenites and forming its patchy texture. This was followed by hydrothermal overgrowths and interstitial titanite, like Notch Peak, but to a lesser extent. Although both plutons had similar emplacement settings–subduction related intrusion into Paleozoic limestone–their whole rock and titanite chemistries are different. The Notch Peak intrusion is more chemically evolved and less mafic than the Little Cottonwood stock. The patchy cores with Fe-Ti oxide inclusions found in the Little Cottonwood stock, along with the abundance of mafic enclaves in the pluton, provide evidence for magma mixing, while no evidence is observed in the Notch Peak intrusion for magma mixing.

This thesis has been conducted at Cargotec Sweden AB as a case study on the loader body of the HIAB XS 144 crane. The loader body is the innermost part in the cranes arm-system and its fatigue life is critical to the operational life of the whole crane. Welding is the main joining process in Cargotec’s cranes and are often a limiting factor when it comes to fatigue life. The weld joining the column to the loader body is carrying the whole crane moment. Previous testing has shown that this weld often limits the fatigue life of the loader body, it has thus been evaluated. Weld fatigue life is affected by a large amount of parameters. To pinpoint the parameters mainly affecting the weld fatigue life and to understand their influence, calculations have been organized using factorial design. The evaluation has been carried out using 3D finite element calculations utilizing sub-modelling to calculate local stresses in the weld notches. Different parameters have been evaluated based on their influence on the local notch stresses. To estimate stresses from the evaluated parameters, regression equations have been fitted. The effective notch method has been used to estimate weld fatigue life. The evaluation has shown that a butt-weld design with root-support, only being welded from the outside of the loader body, as used on some other crane models, could not provide a robust design for the XS 144 crane. The evaluation could also point out several critical parameters that need to be considered when using such design. Apart from the local weld geometry, plate thickness, plate angle, material offset and thickness in the casted column were mainly affecting the weld notch stresses.

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The purpose of this study was to examine the prevalence and characteristics of audiograms that are notched (1) at 4,000 Hz and (2) at 3,000, 4,000, and/or 6,000 Hz. Bilateral audiograms from 1,000,001 veterans were obtained from Department of Veterans Affairs archives; after "cleaning" algorithms were applied, 744,553 participants (mean age = 63.5 yr) were included in the 4,000 Hz notch analysis (group 1) and 539,932 participants (mean age = 62.2 yr) were included in the 3,000, 4,000, and/or 6,000 Hz notch analysis (group 2). A notch was defined when the threshold at the notch frequency (3,000, 4,000, or 6,000 Hz) minus the 2,000 Hz threshold and the threshold at the notch frequency minus the 8,000 Hz threshold both were greater than or equal to 10 dB. In group 1, 77.1% did not have a notch at 4,000 Hz. In group 2, 65.3% did not have a notch at 3,000, 4,000, or 6,000 Hz; 12.4% had bilateral notches, 11.7% had left ear notches, and 10.7% had right ear notches. The notches were about twice as deep on the low-frequency side of the notch than on the high-frequency side. The mean left ear and right ear notch depths were about the same (23 dB), with mode notch depths in the 15.0 to 17.5 dB range.

The purpose of this study was to examine the prevalence and characteristics of audiograms that are notched (1) at 4,000 Hz and (2) at 3,000, 4,000, and/or 6,000 Hz. Bilateral audiograms from 1,000,001 veterans were obtained from Department of Veterans Affairs archives; after "cleaning" algorithms were applied, 744,553 participants (mean age = 63.5 yr) were included in the 4,000 Hz notch analysis (group 1) and 539,932 participants (mean age = 62.2 yr) were included in the 3,000, 4,000, and/or 6,000 Hz notch analysis (group 2). A notch was defined when the threshold at the notch frequency (3,000, 4,000, or 6,000 Hz) minus the 2,000 Hz threshold and the threshold at the notch frequency minus the 8,000 Hz threshold both were greater than or equal to 10 dB. In group 1, 77.1% did not have a notch at 4,000 Hz. In group 2, 65.3% did not have a notch at 3,000, 4,000, or 6,000 Hz; 12.4% had bilateral notches, 11.7% had left ear notches, and 10.7% had right ear notches. The notches were about twice as deep on the low-frequency side of the notch than on the high-frequency side. The mean left ear and right ear notch depths were about the same (23 dB), with mode notch depths in the 15.0 to 17.5 dB range.

The underlying goal of neuroscience research is to understand how the nervous system functions to bring about behavior. A detailed map of neural circuits is required for scientists to tackle this question. To this purpose, we developed a synthetic and genetically-encoded system, TRanscellular ACtivation of Transcription (TRACT) to monitor cell-cell contact. Upon ligand-receptor interaction at sites of cell-cell contact, the transmembrane domain of an engineered Notch receptor is cleaved by intramembrane proteolysis and releases a fragment that regulates transcription in the receptor-expressing cell. We demonstrate that in cultured cells, the synthetic receptor can be activated to drive reporter gene expression by co-incubation with ligand-expressing cell or by growth on ligand-coated surfaces. We further show that TRACT can detect interactions between neurons and glia in the Drosophila brain; expressing the ligand in spatially-restricted subsets of neurons leads to transcription of a reporter in the glial cells that interact with those neurons. To optimize TRACT for neural tracing, we attempted to target the synthetic receptor to post-synaptic sites by fusion with the intracellular domain of Drosophila neuroligin2. However, this modification only facilitate the receptor to be localized homogeneously throughout the neurites. The induction data of the modified receptor shows that the new receptor has better sensitivity compared to the original receptor, but the ligand-receptor interaction still happened at non-synaptic sites of membrane contact. To further target the ligand to pre-synaptic sites, we fused the ligand to different pre-synaptic markers. We found the one fused with synaptobrevin is likely located at axon terminals, but only able to trigger moderate induction. Therefore, more examinations are required to further characterize the capability of this ligand. In summary, TRACT is useful for monitoring cell-cell interactions in animals and could also be used to genetically manipulate cells based on contact. Moreover, we believe that proper targeting of the ligand to synaptic sites will improve the specificity of TRACT for synaptic connections in the future.

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第21261号 / 医博第4379号 / 新制||医||1029(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 山下 潤, 教授 湊谷 謙司, 教授 羽賀 博典 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

京都大学 / 0048 / 新制・論文博士 / 博士(医学) / 乙第13213号 / 論医博第2163号 / 京都大学大学院医学研究科脳統御医科学系専攻 / (主査)教授 山下 潤, 教授 髙橋 良輔, 教授 木村 剛 / 学位規則第4条第2項該当 / Doctor of Medical Science / Kyoto University / DFAM