Spiral - Imperial College Digital Repository
The influence of out-of-plane geometry on pulsatile flow within a distal end-to-side anastomosis.
Get PDFUsing functional analysis diagrams for production cost optimization
Get PDFThis paper presents a methodology combining Failure Mode and Effects Analysis (FMEA) and Value Engineering (VE), assisted by a set of hierarchical Functional Analysis Diagram (FAD) models, and its pilot introduction in a UK-based manufacturing Small Medium Enterprise (SME). The proposed methodology suggests the parallel execution of both processes, using a combination of FAD models and the FMEA tabular tool to yield results for both FMEA and VE. The resulting Risk Priority Number (RPN) is used to identify and prioritize not only the high-risk components requiring improvements (highest RPN values), but also the potentially superfluous components (lowest RPN values
Modeling the voltage loss mechanisms in lithium-sulfur cells: the importance of electrolyte resistance and precipitation kinetics.
Get PDFPrimary care: a fading jewel in the NHS crown
Get PDFWhen Jeremy Hunt, the Secretary for State for Health in England, presented his ‘New Deal for General Practice’ in June 2015, he described general practice as the jewel in the crown of the NHS. Many general practitioners (GPs) though will not be reassured by his statement. Despite Jeremy Hunt’s words of support, the future for GPs, their teams and their patients looks very uncertain. It is hard to see how planned levels of funding for the NHS in England can sustain a readily accessible, high-quality primary care service. It seems likely that primary care in England will increasingly be delivered by non-medical professionals, such as pharmacists, nurses, physician assistants and health care assistants. The acceptability to patients – and the impact on quality of care, patient outcomes and the other parts of the NHS – of this model are all unknown. An alternative scenario is that we gradually move to a ‘two-tier’ primary care system with those patients who can afford to do so paying to see a medically qualified GP
AxiSEM: broadband 3-D seismic wavefields in axisymmetric media
Get PDFWe present a methodology to compute 3-D global seismic wavefields for realistic earthquake sources in visco-elastic anisotropic media, covering applications across the observable seismic frequency band with moderate computational resources. This is accommodated by mandating axisymmetric background models that allow for a multipole expansion such that only a 2-D computational domain is needed, whereas the azimuthal third dimension is computed analytically on the fly. This dimensional collapse opens doors for storing space–time wavefields on disk that can be used to compute Fréchet sensitivity kernels for waveform tomography. We use the corresponding publicly available AxiSEM (www.axisem.info) open-source spectral-element code, demonstrate its excellent scalability on supercomputers, a diverse range of applications ranging from normal modes to small-scale lowermost mantle structures, tomographic models, and comparison with observed data, and discuss further avenues to pursue with this methodology
Aziridine–Metathesis based Approaches to Alkaloid Synthesis
Get PDFThe aim of the project is to synthesise (–)-morphine utilising aziridine and metathesis
chemistry. The thesis is divided into three chapters.
Chapter 1 provides brief reviews on the subjects of total synthesis of morphine; ringrearrangement
metathesis (RRM) and regioselective ring-opening of aziridines.
Chapter 2 focuses on the research findings in the past three years. Two routes, A and B,
were investigated in attempts to synthesise morphine (Scheme 1). In route A, sulfonyl
cyclopentene II was prepared from ring-closing metathesis of a diene precursor, which
was synthesised from lithiated cinnamylsulfone and butadiene monoxide. Subsequently,
RRM reactions of several α-SO2Ph allyl derivatives of II were investigated and some
interesting results were obtained. The synthesis of 2,3-trans vinylaziridine III was
achieved in seven steps beginning with a Grignard reaction of (4-
methoxyphenyl)magnesium bromide with butadiene monoxide. Subsequently, some
highly regioselective ring-opening reactions of III with sulfur-stabilised anionic
nucleophiles were achieved. However, in an attempt to synthesise compound I from II
and III, no reaction was observed. This led to the investigation of route B, in which five
methods for the synthesis of compound IV were investigated. The practical approach
deployed a novel Al-mediated substitution of the 4-tosyl group of the tosyl
tetrahydropyridine counterpart of IV, prepared from V and III, with a phenylthio group.
Chapter 3 provides the experimental details and characterisation data
