The current study investigates the formability of ZEK100, a rare-earth containing magnesium alloy, using an in-house developed technique of pneumatic bulge forming. The thesis pursued innovation of sample preparation, testing, and experimental data analysis in order to create several forming limit diagrams (FLDs) of critical importance for determining a methodology for Mg formability. Samples were bulged through elliptical and circular dies at room temperature, 150 C, and 250 C, in two orientations, rolling direction (RD) and transverse direction (TD), in order to determine temperature dependence and orientation characteristics. The current research concluded ZEK100 is not a suitable alloy for room temperature forming processes used in automotive industries. Little difference between safe and marginal, as well as marginal and failure strain ratios was seen for RD orientation testing, while greater resolution is evident for TD orientation testing. ZEK100 exhibits a temperature dependence in relation to limiting strain between RD and TD.

A mathematical model considering ellipsoidal surface for the forming tube is proposed in this work to examine the plastic deformation behavior of a thin-walled tube during tube bulge hydroforming process in an open die. In the formulation of this mathematical model, nonuniform thinning in the free bulged region and sticking and sliding friction modes between the tube and die are considered. In the sticking friction mode, the elements in contact with the die do not move or slide after contact with the die. Whereas, in the sliding friction mode, the elements in contact with the die will continue to deform plastically in the subsequent forming process. The relationship between the internal pressure and the bulge height of the tube is examined. The effects of various forming parameters such as the die entry radius, the initial thickness, the length/diameter ratio, material property, etc., upon the forming pressure and the thickness distribution of products were discussed systematically.

In this thesis, the author, who participated in the Battle of the Bulge, recreates the story of the battle.

Yes / The cutaneous healing response has evolved to occur rapidly, in order to minimize infection and to re‐establish epithelial homeostasis. Rapid healing is achieved through complex coordination of multiple cell types, which importantly includes specific cell populations within the hair follicle (HF). Under physiological conditions, the epithelial compartments of HF and interfollicular epidermis remain discrete, with K15+ve bulge stem cells contributing progeny for HF reconstruction during the hair cycle and as a basis for hair shaft production during anagen. Only upon wounding do HF cells migrate from the follicle to contribute to the neo‐epidermis. However, the identity of the first‐responding cells, and in particular whether this process involves a direct contribution of K15+ve bulge cells to the early stage of epidermal wound repair remains unclear. Here we demonstrate that epidermal injury in murine skin does not induce bulge activation during early epidermal wound repair. Specifically, bulge cells of uninjured HFs neither proliferate nor appear to migrate out of the bulge niche upon epidermal wounding. In support of these observations, Diphtheria toxin‐mediated partial ablation of K15+ve bulge cells fails to delay wound healing. Our data suggest that bulge cells only respond to epidermal wounding during later stages of repair. We discuss that this response may have evolved as a protective safeguarding mechanism against bulge stem cell exhaust and tumorigenesis. / BBSRC.

Weight reduction is a hot topic in automotive industry. Both the applications of tube hydroforming technique and magnesium alloys offer a large potential for reducing the weight of automotive components. In this research, the relationship between forming pressure and bulge height, the maximum forming pressure and the forming limit during the tube hydraulic bulging process are first analysed. A self-designed warm hydraulic bulge forming equipment and the seamlessly extruted magnesium alloy AZ61 tubes, are used for carrying out a series of warm hydraulic bulge tests, and discussing the formalibility of the magnesium tubes at various temperatures. Furthermore, the flow stress curves are determined by the mathematical model in this paper with the bulge forming test results. Then the validity of the analytical model is verified by comparing the forming pressure and bulge height between analytical and experimental values.

This paper examines 878 mergers and acquisitions between 2003 and 2012 to investigate the impact of advisor choice on transaction performance. Differentiating between bulge bracket, boutique and mixed team advisors, this analysis uses cumulative abnormal announcement returns, purchase premiums, completion ratios, and deal durations as indicators of outcome. Using ordinary least squares and probit regressions an analysis of premium outcomes and target abnormal returns point to there being significant shareholder benefits to using boutique advisors. However, the use of boutiques significantly increases the length of the transaction, and appears to have no impact on the likelihood of a successful completion.

We perform spectral energy distribution fitting to the total integrated light, bulge and disk components of ≈ 650,000 spectroscopically selected galaxies from the sloan digital sky survey data release 7. Using 4-band photometry (u, g, r, i) we derive physical properties for these components with particular emphasis placed on the star formation rates (SFR) and stellar masses. Using the total integrated fits as an indicator of the goodness of fit, we show that reliable estimates of the SFR can be recovered using a specific SFR (sSFR) cut of log(sSFR /yr) ≥ −10.45. We construct a close pairs sample and match isolated controls based on stellar mass, z and local density for galaxies that pass the sSFR cut. We develop a method to cross correlate the pair galaxies’ star formation rate posterior probability distribution functions (SFR PDFs) with the control SFR PDFs as a function of the pair galaxies projected separation, rp. We show that the SFR of the close pair galaxies is enhanced relative to the control sample. The SFR enhancement is at a level of ≈ 0.25 dex above that of the control at the closest separations and declines to a plateau at ≈ 0.15 dex for separations of 30 < rp < 60 kpc/h. Between 60 < rp < 80 kpc/h there appears to be a slight increase in the enhancement to a level ≈ 0.25 dex above the control. It is suggested that we observe this increase, where other studies have failed to, based on the updated photometry provided by Simard et al. (2011). From our total pair sample we also select a subsample of galaxies that are classified as active galactic nuclei (AGN). We note that at close separations the pair AGN galaxies have enhanced SFRs relative to their matched controls. The SFR enhancement is largest at the smallest separations, reaching a level of ≈ 0.3 dex above the control. The SFR enhancement for the AGN pairs becomes consistent with their controls at projected separations of 20 < rp < 80 kpc/h. We construct a bulge and disk pair sample that are required to pass the sSFR cut and match control bulges and disks, respectively, that also pass the sSFR cut. We cross correlate the bulge and disk pairs with their respective controls. We measure significant SFR enhancement in the bulge component of the interacting pairs. The SFR enhancement is highest at small separations, ≈ 0.4 dex, and steadily declines to ≈ 0.1 dex before turning around beyond rp > 50 kpc/h to again reach a level ≈ 0.4 dex above the control bulges. The disk SFR enhancement is relatively flat beyond rp > 30 kpc/h to a level ≈ 0.1 dex above the control and largely consistent with the control at close separations. The bulge and disk results suggest that the majority of induced star formation during an interaction is occurring in the bulge component, but that there is still slight SFR enhancement in the disk. We suggest that the upturn in the total and bulge SFR enhancement could potentially be caused by a delay between the interaction of the galaxy pairs and the onset of induced star formation. / Graduate

The Apache Point Observatory Galactic Evolution Experiment (APOGEE) provides spectroscopic information of regions of the inner Milky Way, which are inaccessible to optical surveys. We present the first large study of the metallicity distribution of the innermost Galactic regions based on high-quality measurements for 7545 red giant stars within 4.5 kpc of the Galactic center, with the goal to shed light on the structure and origin of the Galactic bulge. Stellar metallicities are found, through multiple Gaussian decompositions, to be distributed in several components, which is indicative of the presence of various stellar populations such as the bar or the thin and the thick disks. Super-solar ([Fe/H] = +0.32) and solar ([Fe/H] = +0.00) metallicity components, tentatively associated with the thin disk and the Galactic bar, respectively, seem to be major contributors near the midplane. A solar-metallicity component extends outwards in the midplane but is not observed in the innermost regions. The central regions (within 3 kpc of the Galactic center) reveal, on the other hand, the presence of a significant metal-poor population ([Fe/H] = -0.46), tentatively associated with the thick disk, which becomes the dominant component far from the midplane (vertical bar Z vertical bar >= +0.75 kpc). Varying contributions from these different components produce a transition region at +0.5 kpc <= vertical bar Z vertical bar <= +1.0 kpc, characterized by a significant vertical metallicity gradient.

This qualitative study explores how youth in Tanzania, with low levels of basic education, manage their personal lives and seek opportunities in the workplace or in post-basic education training programs. In Tanzania, Education for All (EFA) has served as a key focal point of coordination between the government and the international donor community. While substantial attention has centered on the challenges of ensuring the sustainability and quality of EFA, there is relatively little known about the socio-economic circumstances of young school leavers and their perceptions of education and its relation to their post-school life trajectories. Using structuration theory as the theoretical framework to illuminate the dynamic interconnectedness of social structures and youth agency, I conducted semi-structured interviews with 14 young male and female school leavers. Disturbing patterns of social reproduction and a fundamental discontinuity between basic education and post-school challenges were revealed in the research. Yet, in view of their resilience, orientation to the future and entrepreneurial resourcefulness, findings suggest that despite profound qualitative shortcomings, aspects of basic education and the structuring effects of economic liberalization may be contributing to enhanced youth agency. The dissertation contributes to the theoretical discourse in the study of youth phenomena by adapting and advancing Klocker’s (2007) use of the notion of thinners and thickeners of agency within structuration theory. Exploring factors like educational quality and attainment level, in addition to those already established by Klocker (tribe, gender, age, and poverty), my research shows how young people’s agency can be attenuated or accentuated in space and time. This dissertation contributes empirical, hermeneutic and narrative data to illuminate the educational experience and post-basic education realities for a group of Tanzanian youth, reducing what has heretofore been described as a paucity of such qualitative accounts of marginalized African youth and the challenges they face.

Over the past decade the concept that the hair follicle plays an important role in cutaneous wound repair has been established. Several elegant lineage tracing studies have demonstrated that hair follicle derived cells contribute to the long term maintenance of the epidermis following repair, while an absence of hair follicles is known to delay repair. The exact mechanisms surrounding hair follicle derived repair are unknown. Moreover, while multiple stem cell niches are present within the hair follicle, their relative importance during wound repair is still unclear. The hair follicle is also a regenerative mini-organ, undergoing regular cycles of growth and regression throughout life, yet surprisingly this has not been previously investigated with respect to wound repair. Data presented in this thesis reveals an unappreciated, yet fundamental link between the independent processes of hair cycle and wound repair, with a substantial acceleration in the rate of repair (~50%) observed in anagen phase. Importantly, the hair follicle appears to play a global role in repair, with differences in the contribution of multiple cell types to wound repair. In addition, this thesis addresses the early kinetics of hair follicle wound response for the first time. Anagen hair follicles are found predisposed to a more rapid and extensive response to injury, suggesting a higher overall percentage of repair derived from the hair follicle in anagen phase. Surprisingly, the bulge stem cell region, while critical for hair cycle appears to play little role in the events immediately following injury, and is not required for initiation of re-epithelialisation. Gene expression profiling reveals numerous genes associated with anagen accelerated repair, and identifies altered modulation of the immune system as a key mechanism. Further, anagen wounds are associated with an upregulation of developmental transcription factors, which may imply a more regenerative healing phenotype. These data reveal numerous targets with the potential to accelerate repair, which now require validation for their therapeutic potential. These targets could be of importance in promoting the repair of chronic wounds, an area of unmet clinical need. More generally, this thesis has established hair cycle as an important experimental variable, which must be controlled for in all future in vivo murine wounding studies.