Failure of steel gusset plates

This thesis examines the parameters associated with the failure of triangular steel gusset plates. Eighty two results are presented investigating the position of the applied load, the gusset plate height to length ratio, size, thickness, internal angle and the removal of the inside corner. The thickness of the loaded plate and its influence on the gusset plates failure is also investigated. Twenty two similar gusset plates were tested to investigate the welds connecting the gusset plate to the adjacent loaded and support edges. The experimental results are compared with existing methods, none of which cover all the variables tested. Some methods do not consider buckling and most of those that do are inadequate. Most of the methods do not accurately take account of the load position. An alternative method based on experimental observations is presented for design purposes. The method covers any combination of the variables tested. To test assumptions made in the theoretical work forty seven strut tests took place to investigate buckling characteristics and fifteen special gusset plates were also tested. The gusset plates were found to fail in an elastic-plastic buckling manner. A gusset plate has a specific moment of resistance capacity about it’s inside corner and the ultimate load that can be applied is dependent upon the position of the load relative to the supported edge. There is an optimum height to length ratio for strength and any increase in the internal angle from 90 degrees produces little change in moment capacity. The removal of small portions of the inside corner of a gusset plate has little effect upon its moment capacity. The loaded plate does not provide any significant moment of resistance to the applied load at failure. The main functions of the loaded and supported edge welds is to prevent the gusset plate from slipping from between the plates.

Deformation and failure of welded steels used in offshore constructions

Hydrocarbons are the most common form of energy used to date. The activities involving exploration and exploitation of large oil and gas fields are constantly in operation and have extended to such hostile environments as the North Sea. This enforces much greater demands on the materials which are used, and the need for enhancing the endurance of the existing ones which must continue parallel to the explorations. Due to their ease in fabrication, relatively high mechanical properties and low costs, steels are the most widely favoured material for the construction of offshore platforms. The most critical part of an offshore structure prone to failure are the welded nodal joints, particulary those which are used within the vicinity of the splash zones. This is an area of high complex stress concentrations, varying mechanical and metallurgical properties in addition to severe North Sea environmental conditions. The main are of this work has been concerned with the durability studies of this type of steel, based on the concept of the worst case analysis, consisting of combinations of welds of varying qualities, various degrees of stress concentrations and the environmental conditions of stress corrosion and hydrogen embrittlement. The experiments have been designed to reveal significance of defects as sites of crack initiation in the welded steels and the extent to which stress corrosion and hydrogen embrittlement will limit their durability. This has been done for various heat treatments and in some experiments deformation has been forced through the welded zone of the specimens to reveal the mechanical properties of the welds themselves to provide data for finite element simulations. A comparison of the results of these simulations with the actual deformation and fracture behaviour has been done to reveal the extent to which both mechanical and metallurgical factors control behaviour of the steels in the hostile environments of high stress, corrosion, and hydrogen embrittlement at their surface.

The role of adipokines in beta-cell failure of type 2 diabetes

Beta-cell failure coupled with insulin resistance is a key factor in the development of type 2 diabetes. Changes in circulating levels of adipokines, factors released from adipose tissue, form a significant link between excessive adiposity in obesity and both aforementioned factors. In this review we consider the published evidence for the role of individual adipokines on the function, proliferation, death and failure of beta-cells, focusing on those reported to have the most significant effects (leptin, adiponectin, TNFa, resistin, visfatin, DPP-IV and apelin). It is apparent that some adipokines have beneficial effects whereas others have detrimental properties; the overall contribution to beta-cell failure of changed concentrations of adipokines in the blood of obese pre-diabetic subjects will be highly dependent on the balance between these effects and the interactions between the adipokines which act on the beta-cell via a number of intersecting intracellular signalling pathways. We emphasise the importance, and comparative dearth, of studies into the combined effects of adipokines on beta-cells.

The elevation in circulating anti-angiogenic factors is independent of markers of neutrophil activation in preeclampsia

Background - Severe preeclampsia is associated with increased neutrophil activation and elevated serum soluble endoglin (sEng) and soluble Flt-1 (sFlt-1) in the maternal circulation. To dissect the contribution of systemic inflammation and anti-angiogenic factors in preeclampsia, we investigated the relationships between the circulating markers of neutrophil activation and anti-angiogenic factors in severe preeclampsia or systemic inflammatory state during pregnancy. Methods and results - Serum sEng, sFlt-1, placenta growth factor, interleukin-6 (IL-6), calprotectin, and plasma a-defensins concentrations were measured by ELISA in 88 women of similar gestational age stratified as: severe preeclampsia (sPE, n = 45), maternal systemic inflammatory response (SIR, n = 16) secondary to chorioamnionitis, pyelonephritis or appendicitis; and normotensive controls (CRL, n = 27). Neutrophil activation occurred in sPE and SIR, as a-defensins and calprotectin concentrations were two-fold higher in both groups compared to CRL (P < 0.05 for each). IL-6 concentrations were highest in SIR (P < 0.001), but were higher in sPE than in CRL (P < 0.01). sFlt-1 (P < 0.001) and sEng (P < 0.001) were ˜20-fold higher in sPE compared to CRL, but were not elevated in SIR. In women with sPE, anti-angiogenic factors were not correlated with markers of neutrophil activation (a-defensins, calprotectin) or inflammation (IL-6). Conclusions - Increased systemic inflammation in sPE and SIR does not correlate with increased anti-angiogenic factors, which were specifically elevated in sPE indicating that excessive systemic inflammation is unlikely to be the main contributor to severe preeclampsia.

The 3 per cent Barcelona Target: A Critical Appraisal of the Failure of the Lisbon Strategy’s Knowledgebased Economy and Society Project

Ten years after the unanimous approval of the Lisbon Strategy at a special meeting of the European Council on 23-24 March 2000 in Lisbon, it will be inevitable for the European Council, the European Commission and the majority of the EU member states to face with its fi asco and to account for the reasons of their fundamental policy, governance and economic failures in 2010. The recent turbulence of the global economy offers some excuses for the underperformance of the main objectives of the Lisbon Strategy in the essential social and economic domains, like job creation, economic growth, and environmental sustainability. Negative growth rates, macroeconomic and fi nancial instability, the contraction of the internal and external markets of the European economy, drop in demand for capital investment, goods and services, sinking corporate revenues, depreciation of corporate assets, increasing private and public indebtedness, falling rate of employment, weakening social cohesion, widening social inequality, and so forth not only deprive the majority of the EU member states of fulfi lling the main objectives of the Lisbon Strategy but also drive them into worse social and economic conditions in many policy domains than they were in 2000.

Democratic purgatory: The failure of democracy in Venezuela

This research provides an understanding of the conditions that presage the failure of consolidated democratic political regimes through constitutional processes. In seeking to answer the question of how democracy might fail through democratic means, this study has revealed a gap in the literature on democratization. Venezuela was selected as a heuristic case study to explain this phenomenon. Heuristic case studies place less emphasis on the more configurative or descriptive elements of the case itself, and instead see the case as a point of departure for the formulations of theoretical propositions. While in-case hypotheses are possible, heuristic case studies make it an explicit research plan to tease out mechanisms that exist in a particular case study that might survive in other situations. ^ This study demonstrates that the elements in society that act as direct participants in the establishment of a democratic political system are able to maintain their position in the new order largely through an expansion of their ability to meet popular demands through clientelistic arrangements. While these corporatist groups may serve to facilitate social mobilization during the establishment of democratic regimes, they do so only in so far as they can maintain social control of in-group membership without fully providing for representative democracy. Once these democratic institutions are consolidated as key parts of the democratic structure, these corporatist arrangements provide for a type of unstable democratic purgatory: democracy is not fully representative, yet it is not completely unresponsive to the demands of the electorate. ^ The condition of democratic purgatory produces a paradox whereby democracy can be undemocratic under certain conditions. The stability of these regimes allows for democratic consolidation, despite the undemocratic basis of legitimacy. While these regimes can undergo consolidation, ultimately, this condition is unstable: either these regimes must establish an endogenous basis of political legitimacy (one that is not simply a function of the corporatist/clientelistic political structure), or the democracy will suffer a qualitative decline that may result in a democratic breakdown. Furthermore, this study finds that the viability of any type of democratic regime rests upon its adaptability to ensure adequate representativeness. ^

Tracking rates of ecotone migration due to salt-water encroachment using fossil mollusks in coastal South Florida

We determined the rate of migration of coastal vegetation zones in response to salt-water encroachment through paleoecological analysis of mollusks in 36 sediment cores taken along transects perpendicular to the coast in a 5.5 km2 band of coastal wetlands in southeast Florida. Five vegetation zones, separated by distinct ecotones, included freshwater swamp forest, freshwater marsh, and dwarf, transitional and fringing mangrove forest. Vegetation composition, soil depth and organic matter content, porewater salinity and the contemporary mollusk community were determined at 226 sites to establish the salinity preferences of the mollusk fauna. Calibration models allowed accurate inference of salinity and vegetation type from fossil mollusk assemblages in chronologically calibrated sediments. Most sediments were shallow (20–130 cm) permitting coarse-scale temporal inferences for three zones: an upper peat layer (zone 1) representing the last 30–70 years, a mixed peat-marl layer (zone 2) representing the previous ca. 150–250 years and a basal section (zone 3) of ranging from 310 to 2990 YBP. Modern peat accretion rates averaged 3.1 mm yr)1 while subsurface marl accreted more slowly at 0.8 mm yr)1. Salinity and vegetation type for zone 1 show a steep gradient with freshwater communities being confined west of a north–south drainage canal constructed in 1960. Inferences for zone 2 (pre-drainage) suggest that freshwater marshes and associated forest units covered 90% of the area, with mangrove forests only present along the peripheral coastline. During the entire pre-drainage history, salinity in the entire area was maintained below a mean of 2 ppt and only small pockets of mangroves were present; currently, salinity averages 13.2 ppt and mangroves occupy 95% of the wetland. Over 3 km2 of freshwater wetland vegetation type have been lost from this basin due to salt-water encroachment, estimated from the mollusk-inferred migration rate of freshwater vegetation of 3.1 m yr)1 for the last 70 years (compared to 0.14 m yr)1 for the pre-drainage period). This rapid rate of encroachment is driven by sea-level rise and freshwater diversion. Plans for rehydrating these basins with freshwater will require high-magnitude re-diversion to counteract locally high rates of sea-level rise.

Predicting success or failure of tax -base revenue sharing attempts: A comparative analysis

To promote regional or mutual improvement, numerous interjurisdictional efforts to share tax bases have been attempted. Most of these efforts fail to be consummated. Motivations to share revenues include: narrowing fiscal disparities, enhancing regional cooperation and economic development, rationalizing land-use, and minimizing revenue losses caused by competition to attract and keep businesses. Various researchers have developed theories to aid understanding of why interjurisdictional cooperation efforts succeed or fail. Walter Rosenbaum and Gladys Kammerer studied two contemporaneous Florida local-government consolidation attempts. Boyd Messinger subsequently tested their Theory of Successful Consolidation on nine consolidation attempts. Paul Peterson's dual theories on Modern Federalism posit that all governmental levels attempt to further economic development and that politicians act in ways that either further their futures or cement job security. Actions related to the latter theory often interfere with the former. Samuel Nunn and Mark Rosentraub sought to learn how interjurisdictional cooperation evolves. Through multiple case studies they developed a model framing interjurisdictional cooperation in four dimensions. ^ This dissertation investigates the ability of the above theories to help predict success or failure of regional tax-base revenue sharing attempts. A research plan was formed that used five sequenced steps to gather data, analyze it, and conclude if hypotheses concerning the application of these theories were valid. The primary analytical tools were: multiple case studies, cross-case analysis, and pattern matching. Data was gathered from historical records, questionnaires, and interviews. ^ The results of this research indicate that Rosenbaum-Kammerer theory can be a predictor of success or failure in implementing tax-base revenue sharing if it is amended as suggested by Messinger and further modified by a recommendation in this dissertation. Peterson's Functional and Legislative theories considered together were able to predict revenue sharing proposal outcomes. Many of the indicators of interjurisdictional cooperation forwarded in the Nunn-Rosentraub model appeared in the cases studied, but the model was not a reliable forecasting instrument. ^

NOTCH1 Gain of Function in Germ Cells Causes Failure of Spermatogenesis in Male Mice

NOTCH1 is a member of the NOTCH receptor family, a group of single-pass trans-membrane receptors. NOTCH signaling is highly conserved in evolution and mediates communication between adjacent cells. NOTCH receptors have been implicated in cell fate determination, as well as maintenance and differentiation of stem cells. In the mammalian testis expression of NOTCH1 in somatic and germ cells has been demonstrated, however its role in spermatogenesis was not clear. To study the significance of NOTCH1 in germ cells, we applied a cre/loxP approach in mice to induce NOTCH1 gain- or loss-of function specifically in male germ cells. Using a Stra8-icretransgene we produced mice with conditional activation of the NOTCH1 intracellular domain (NICD) in germ cells. Spermatogenesis in these mutants was progressively affected with age, resulting in decreased testis weight and sperm count. Analysis of downstream target genes of NOTCH1 signaling showed an increased expression of Hes5, with a reduction of the spermatogonial differentiation marker, Neurog3 expression in the mutant testis. Apoptosis was significantly increased in mouse germ cells with the corresponding elevation of pro-apoptotic Trp53 and Trp63genes' expression. We also showed that the conditional germ cell-specific ablation of Notch1 had no effect on spermatogenesis or male fertility. Our data suggest the importance of NOTCH signaling regulation in male germ cells for their survival and differentiation.

Indentation failure of circular composite sandwich plates

A. Rajaneesh and A. R. Akisanya acknowledge the financial support from Nanyang Technological University, Singapore through award of Graduate Scholarship and Tan Chin Tuan (TCT) Visiting Fellowship, respectively. I. Sridhar thanks British High Commission, Singapore for facilitating a Collaborative Development Award (CDA) to visit UK Universities for research collaboration.

Indentation failure of circular composite sandwich plates

A. Rajaneesh and A. R. Akisanya acknowledge the financial support from Nanyang Technological University, Singapore through award of Graduate Scholarship and Tan Chin Tuan (TCT) Visiting Fellowship, respectively. I. Sridhar thanks British High Commission, Singapore for facilitating a Collaborative Development Award (CDA) to visit UK Universities for research collaboration.

Contact-mediated control of radial migration of corneal epithelial cells

We thank Darrin Sheppard and other staff at the University of Aberdeen Medical Research Facility for specialist technical assistance. We thank Patsy D. Goast for overnight microscope monitoring. This work was performed under the Biotechnology and Bioscience Research Council Grant number BB/E015840/1 to JMC.

Transcultural satire in German fiction of Turkish migration: Self-deprecation, ethnic impersonation, intertexuality

My dissertation presents a study of satire in contemporary German Fiction of Turkish migration. Engaging with a body of works hitherto neglected in scholarship, I examine how satirical texts, films, and plays intervene critically in discourses on post-unification German national identity. Drawing on the seminal work of scholars such as Leslie Adelson, Tom Cheesman, B. Venkat Mani, Petra Fachinger, and Deniz Göktürk, my dissertation expands the scholarship of Turkish German Studies by linking a discussion of satire as a critical rhetoric to the question of how we talk about what it means to be German.

Chapter one offers a novel framework of the satirical vis-à-vis standard conceptions of satire and deconstructionist theories of reading. I understand satire as a form of rhetoric that creates moments of ambiguity by bringing together intersectional categories like gender, ethnicity, race, religion, in order to challenge the audience’s practices of interpreting cultural otherness. Chapter two examines the use of ethnic self-deprecation as one such strategy in Osman Engin’s short stories and his first novel, Kanaken-Ghandi through the lens of Bakhtinian polyphony and Judith Butler’s work on hate speech. Engin, I argue, employs ethnic selfdeprecation as a narrative strategy to straddle the line between deconstructing and re-affirming cultural stereotypes. Investigating the role of ethnic impersonation in Hussi Kutlucan’s film Ich Chef, Du Turnshuh, the third chapter turns to the question of ethnicity as a visual signifier for the negotiation of cultural inclusion and exclusion in post-1990 film. In dialogue with Katrin Sieg’s work on ethnic drag and Amy Robinson’s theory of passing, I show how the film challenges ethnically-coded narratives of Germanness. In the final chapter on Nurkan Erpulat and Jens Hillje’s play Verrücktes Blut, I discuss how intertextuality and adaptation (Hutcheon, Genette) of different story and character worlds are used to create moments of ambiguity and overdeterminacy in the play, in order to challenge the audience’s perception of what an inclusive German society might look like.

The impact of gestational age and fetal weight on the risk of failure of spinal anesthesia for cesarean delivery.

BACKGROUND: There are limited data about spinal dosing for cesarean delivery in preterm parturients. We investigated the hypothesis that preterm gestation is associated with an increased incidence of inadequate spinal anesthesia for cesarean delivery compared with term gestation. METHODS: We searched our perioperative database for women who underwent cesarean delivery under spinal or combined spinal-epidural anesthesia with hyperbaric bupivacaine ⩾10.5mg. The primary outcome was the incidence of inadequate surgical anesthesia needing conversion to general anesthesia or repetition or supplementation of the block. We divided patients into four categories: <28, 28 to <32, 32 to <37 and ⩾37weeks of gestation. The chi-square test was used to compare failure rates and a multivariable regression analysis was performed to investigate potential confounders of the relationship between gestational age and failure. RESULTS: A total of 5015 patients (3387 term and 1628 preterm) were included. There were 278 failures (5.5%). The incidence of failure was higher in preterm versus term patients (6.4% vs. 5.1%, P=0.02). Failure rates were 10.8%, 7.7%, 5.3% and 5% for <28, 28 to <32, 32 to <37 and ⩾37weeks of gestation, respectively. In the multivariable model, low birth weight (P<0.0001), gestational age (P=0.03), ethnicity (P=0.02) and use of combined spinal-epidural anesthesia (P<0.0001) were significantly associated with failure. CONCLUSIONS: At standard spinal doses of hyperbaric bupivacaine used in our practice (⩾10.5mg), there were higher odds of inadequate surgical anesthesia in preterm parturients. When adjusting for potential confounders, low birth weight was the main factor associated with failure.