Development of a machine-tooling-process integrated approach for abrasive flow machining (AFM) of difficult-to-machine materials with application to oil and gas exploration componenets

This thesis was submitted for the degree of Doctor of Engineering and awarded by Brunel UniversityAbrasive flow machining (AFM) is a non-traditional manufacturing technology used to expose a substrate to pressurised multiphase slurry, comprised of superabrasive grit suspended in a viscous, typically polymeric carrier. Extended exposure to the slurry causes material removal, where the quantity of removal is subject to complex interactions within over 40 variables. Flow is contained within boundary walls, complex in form, causing physical phenomena to alter the behaviour of the media. In setting factors and levels prior to this research, engineers had two options; embark upon a wasteful, inefficient and poor-capability trial and error process or they could attempt to relate the findings they achieve in simple geometry to complex geometry through a series of transformations, providing information that could be applied over and over. By condensing process variables into appropriate study groups, it becomes possible to quantify output while manipulating only a handful of variables. Those that remain un-manipulated are integral to the factors identified. Through factorial and response surface methodology experiment designs, data is obtained and interrogated, before feeding into a simulated replica of a simple system. Correlation with physical phenomena is sought, to identify flow conditions that drive material removal location and magnitude. This correlation is then applied to complex geometry with relative success. It is found that prediction of viscosity through computational fluid dynamics can be used to estimate as much as 94% of the edge-rounding effect on final complex geometry. Surface finish prediction is lower (~75%), but provides significant relationship to warrant further investigation. Original contributions made in this doctoral thesis include; 1) A method of utilising computational fluid dynamics (CFD) to derive a suitable process model for the productive and reproducible control of the AFM process, including identification of core physical phenomena responsible for driving erosion, 2) Comprehensive understanding of effects of B4C-loaded polydimethylsiloxane variants used to process Ti6Al4V in the AFM process, including prediction equations containing numerically-verified second order interactions (factors for grit size, grain fraction and modifier concentration), 3) Equivalent understanding of machine factors providing energy input, studying velocity, temperature and quantity. Verified predictions are made from data collected in Ti6Al4V substrate material using response surface methodology, 4) Holistic method to translating process data in control-geometry to an arbitrary geometry for industrial gain, extending to a framework for collecting new data and integrating into current knowledge, and 5) Application of methodology using research-derived CFD, applied to complex geometry proven by measured process output. As a result of this project, four publications have been made to-date – two peer-reviewed journal papers and two peer-reviewed international conference papers. Further publications will be made from June 2014 onwards.Engineering and Physical Sciences Research Council (EPSRC) and the Technology Strategy Board (TSB

Panama Canal Tolls: Instruction of the Secretary of State of January 17, 1913, to the American Charge D\u27Affaires at London, and the British Notes of July 8, 1912, and November 14, 1912, to Which it Replies

This book is a collection of typed letters and documents between the Taft administration and the foreign service of Great Britain on the opening of the Panama Canal and the placing of tolls on vessels using the canal. The reports draw on the Clayton-Bulwer Treaty of 1850 giving equal importance of the US and Great Britain in New World trading as well as the Hay-Pauncefote Treaty of 1901 allowing the US to build the Panama canal.https://digitalcommons.ursinus.edu/fmhw_speeches/1012/thumbnail.jp

A Comparison Study of Eleven Static Heuristics for Mapping a Class of Independent Tasks onto Ileterogeneous Distributed Computing Systems

ABSTRACT Il\u27lixed-machine heterogeneous computing (HC) environments utilize a distributed suite of different high-performance machines, interconnected with high-speed links to perform different computationally intensive applications that have diverse comput ational requirements. HC environments are well suited to meet thl: computational dell-tands of large, diverse groups of tasks. The problem of mapping (defined as matching and scheduling) these tasks onto the machines of a distributed HC environment has been shown, in general, to be NP-complete, requiring the development of heuristic techniques. Selecting the best heuristic to use in a given enviroi~menth, owever, remains a difficult problem, because comparisons are often clouded by different underlying assumptions in the original studies of each heuristic. There~fore; a collection of eleven heuristics from the literature has been selected: a,dapted, in~plementeda, nd anaiyzed under one set of common assumptions. It is assumed that the heuristics derive a, mapping statically (i.e., off-line). It is also assumed that a meta-task (i.e., a set of independent, non-communicating tasks) is being mapped, and that the goal is to minimize the total execution time of the metla-task. The eleven heuristics examined are Opportunistic Load Balancing, Minimum Execution Time, MininLlum Clompletion Time, Min-min, hllax-min, Duplex? Genetic i-Ilgorithm, Simulated Annealing, Genetic Simulat.ed .Annealing, Tabu, and Ax. This study provides one even basis for comparisor] and insights into circumstances where one technique will out perform another. The evaluation procedure is specified, the heuristics are defined, and then comparison results are discussed. It is shown that for the ca.ses studied here, the relat,ively simple Min-min heuristic performs well in comparison to the other techniques

Embedding clinical interventions into observational studies

Novel approaches to observational studies and clinical trials could improve the cost-effectiveness and speed of translation of research. Hybrid designs that combine elements of clinical trials with observational registries or cohort studies should be considered as part of a long-term strategy to transform clinical trials and epidemiology, adapting to the opportunities of big data and the challenges of constrained budgets. Important considerations include study aims, timing, breadth and depth of the existing infrastructure that can be leveraged, participant burden, likely participation rate and available sample size in the cohort, required sample size for the trial, and investigator expertise. Community engagement and stakeholder (including study participants) support are essential for these efforts to succeed

Matrix Metalloproteinase-1 is the Major Collagenolytic Enzyme Responsible for Collagen Damage in UV-irradiated Human Skin ¶

Punch biopsies of human skin were obtained 1 day after irradiation with two minimal-erythema doses (MED) from either a UVB light source or a Solar Simulator and incubated in organ culture for 72 h. Organ culture fluids obtained at 24, 48 and 72 h were analyzed for collagenolytic activity and for reactivity with antibodies to matrix metalloproteinase-1 (MMP-1; interstitial collagenase) and MMP-13 (collagenase-3). High levels of collagenolytic activity were seen in organ culture fluid from skin exposed to either light source. MMP-1 was strongly induced in parallel, increasing from less than 100 ng/ml in organ culture fluid from control skin to approximately 1.1 mg/ml in culture fluid from UV-treated skin. Whereas most of the detectable MMP-1 in control culture fluid was represented by the latent form of the enzyme, approximately 50% of the enzyme was present as the active form in organ culture fluid of UV-exposed skin. In contrast, there was no detectable MMP-13 in control organ culture fluid and very little change after UV exposure (less than 100 ng/ml in both cases). Finally, neutralization studies with a blocking antibody to MMP-1 removed 95 ± 4% of the collagenolytic activity in the organ culture fluid from UV-treated skin. These findings strongly implicate MMP-1 rather than MMP-13 as the major collagenolytic enzyme responsible for collagen damage in photoaging.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73069/1/0031-8655_2003_0780043MMITMC2.0.CO2.pd

Nature and mental health: An ecosystem service perspective

A growing body of empirical evidence is revealing the value of nature experience for mental health. With rapid urbanization and declines in human contact with nature globally, crucial decisions must be made about how to preserve and enhance opportunities for nature experience. Here, we first provide points of consensus across the natural, social, and health sciences on the impacts of nature experience on cognitive functioning, emotional well-being, and other dimensions of mental health. We then show how ecosystem service assessments can be expanded to include mental health, and provide a heuristic, conceptual model for doing so

Visual methodologies, sand and psychoanalysis: employing creative participatory techniques to explore the educational experiences of mature students and children in care

Social science research has witnessed an increasing move towards visual methods of data production. However, some visual techniques remain pariah sites because of their association with psychoanalysis; and a reluctance to engage with psychoanalytically informed approaches outside of therapy based settings. This paper introduces the method of ‘sandboxing’, which was developed from the psychoanalytical approach of the ‘world technique’. ‘Sandboxing’ provides an opportunity for participants to create three-dimensional scenes in sand-trays, employing miniature figures and everyday objects. Data is presented from two studies conducted in Wales, UK. The first, exploring mature students’ accounts of higher education, and the second, exploring the educational experiences of children and young people in public care. The paper argues that psychoanalytical work can be adapted to enable a distinctive, valuable and ethical tool of qualitative inquiry; and illustrates how ‘sandboxing’ engendered opportunities to fight familiarity, enabled participatory frameworks, and contributed to informed policy and practice

Effects of antiplatelet therapy on stroke risk by brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases: subgroup analyses of the RESTART randomised, open-label trial

Background Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy

Writing in Britain and Ireland, c. 400 to c. 800

No abstract available