MSc & MSc Funded Theses
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Item Open Access A novel cryogenic storage solution for atmosphere-breathing electric propulsion systems(Cranfield University, 2021-08) Leslie, Cameron Fraser; Hobbs, Stephen E.Recent interest in missions to Very Low Earth Orbit (VLEO) has led to the emergence of Atmosphere Breathing Electric Propulsion (ABEP). In theory this technology could enable missions to VLEO that forego the need to launch with propellant. This innovative concept could allow the full potential of low altitude regimes to be exploited as propellant consumption no longer limits lifetime. The most promising designs use a passive intake system that requires no moving parts to operate. Natural phenomena caused by the flow conditions at orbital velocity are exploited to provide an electric thruster with an adequate supply of gas. However a previously identified shortfall in its capabilities is that no propellant is stored during operation. This leaves the system at the mercy of the unpredictable conditions witnessed in Earth’s atmosphere. This thesis proposes a solution to this problem. If molecules ingested by a passive intake can be cooled to cryogenic temperatures, they can be temporarily captured so long as they are kept cold. This phenomenon has the potential to be exploited as an in-orbit propellant storage system. To investigate this concept, firstly a baseline mathematical model for an ABEP system was constructed using current design methodologies. Secondly, this system was adapted to incorporate the novel storage concept. The resulting model was then compared to the baseline along common performance parameters in order to assess its feasibility. The results showed that during the collection of propellant the requirements on flow conditions for adequate performance became more stringent. Nevertheless a feasible operating region was found and a baseline system chosen. This design point allowed for a propellant collection rate of between 0.43 mg/s and 0.74 mg/s. At this rate of collection, calculations speculated a potential for >1000 m/s of Δv over an 8 year mission could be gained. If realised, the potential mission applications are vast and could not only complement the performance of ABEP systems but open up novel mission concepts such as in-orbit refuelling.Item Open Access Analysis of MRSA Staphylococcal Chromosome cassette mecA status from next generation sequence data(Cranfield University, 2012-03) Goulden, Matthew G; Larcombe, Lee D; Clark, Taane; Bessant, ConradNGS sequencing libraries prepared on an Illumina NGS platform for 10 isolates of Staphylococcus aureus were analysed. After extensive pre-processing to address library quality issues, for each isolate the status of the Staphylococcal Chromosome Cassette, and its mecA gene specifying resistance to meticillin, was determined. All mecA-positive isolates encoded canonical mecA. None encoded the new variant mecA identified in strain LGA251.Item Open Access The knowledge management requirements for the transfer of a stroke patient(Cranfield University, 2009-09) Ellingham, Brett; Wainwright, CharlesHealth care is characterised by complexity, in terms of structure and number of individuals, teams & autonomous local organisations involved in the delivery of care. An obvious requirement in maintaining continuity for the patient is knowledge transferred between these groups. An example of this is the transfer of a stroke patient from one setting for their acute care to another for their rehabilitation. Objectives of the research were within the context of a stroke patient transfer, to determine the knowledge management needs of the receiving community hospital team, provision of knowledge from the acute hospital team, shortcomings emanating from the current state and solutions for future better ways of working. Research took the form of an exploratory case study involving semi-structured interviews with clinicians involved in specialist stroke care. Findings showed that Knowledge Management is one of a number of management issues facing stroke care for the organisations studied, though currently not the most pressing. Operational, rather than clinical knowledge showed most scope for improvement. Current practises rely heavily on knowledge transfer by people, which was deemed appropriate in most cases. The research provides an insight into knowledge management within health care at an operational level, specifically applied to stroke and patient transfers; examples of which could provide insight for other specific events in a patient’s journey. Practically, conclusions could be used to guide ongoing improvement to process development for the acute and community hospital teams studied, as well as provide lessons for the opening of further community hospital stroke units.Item Open Access Performance evaluation of UAM configurations cost estimation for the eVTOLs.(Cranfield University, 2021-08) Wu, Xiaolong; Lu, LinghaiWith the development and progress of society, the pressure on road traffic is increasing daily, causing enormous time and economic losses to the public. The concept of electric vertical take-off and landing vehicles (eVTOLs) was proposed in order to identify a speedy and effective way of commuting in congested cities. There are many different categories of eVTOLs on the market and many countries and companies are developing it, however the various types of vehicles have different target scenarios and will incur different operating costs. This research project will identify the most suitable configuration of eVTOL in the given scenario, predict its cost and present the lowest cost optimisation solution. The research project started with a reference and evaluation of the similarities and differences between the cost structure of electric general aviation and eVTOL. Top-down, bottom-up and parametric methods were then used to initially determine the cost structure and cost formula. Furthermore, the Lilium five-seater configuration was identified as the target for this project based on the requirements of the specified scenario. Finally, the operating cost per seat-mile, operating cost per hour, annual operating cost and the optimal trajectory schedule were obtained for the specified scenario.