How are undergraduate students supervised? Supervisor and student perspectives on undergraduate dissertation supervision in an elite UK university

The undergraduate dissertation is a significant component of many undergraduate programs in the UK, representing a crucial contribution to the immediate degree award outcome and a key stage in the long-term development of potential academic researchers. From the recognition of the undergraduate dissertation as a high-stakes project, most universities assign an individual supervisor to students in order to ensure the successful completion of the dissertation and foster the intellectual and scholarly development of students. Whilst much has been written about the function and purpose of supervision, less is known about undergraduate supervision as an intensive and interpersonally focused one-to-one relationship that spans the duration of dissertation research. Using an explanatory sequential mixed-method design, this study explored the perceptions and experiences of finalist undergraduates and their dissertation supervisors in social science at an elite university in the UK and investigated the assumptions, beliefs and objectives shaping students and supervisors’ approaches to supervision along the dissertation journey. Major findings from the quantitative analysis demonstrate changing supervisory involvement in response to different research tasks and point to an apparent mismatch between student demand for and supervisor provision of support in a relatively late phase of the dissertation. Qualitative findings add nuance and context to patterns already observed in survey responses and illuminate issues that would not have arisen had this study stopped at the quantitative stage, such as the significance of open communication and mutual understanding for a healthy and productive student-supervisor relationship. The two sources of evidence identify undergraduate supervision as multi-stage and non-uniform, as the level and type of supervisory support involved in supervision varied not just throughout the year but also with the student-supervisor pair. The findings represent an original contribution to the existing literature on undergraduate supervision and may offer useful considerations to policymakers and undergraduate supervisors within the social science division at the case university. Generalisability is limited due to the small sample and the unique context in which this research was situated. That said, findings may have some transferability to similar settings, though any effort in this regard shall be made with caution

Mixed-fidelity CFD Simulations for Aero-engines: A Fan-intake Interaction Study

Engine system consists of complex components, where aerodynamics can be coupled. In these coupled problems, flow separation may exist and the multiscale turbulence needs to be finely resolved to obtain an accurate solution. A high-fidelity simulation in such scenarios, however, is still infeasible for industrial applications due to the limitation of current computational resources. To make it possible, a mixed-fidelity CFD method based on the Immersed Boundary Method (IBM) is proposed. In this hierarchical method, geometries can be replaced by forces, i.e. the standard IBM or eIBM, whereas turbulence can be resolved by the Large Eddy Simulation. The thesis proposed this method and applied it to an important issue for engine design: fan-intake interaction. The method was validated on a Darmstadt Transonic Rotor with a distortion generator to replicate the unsteady distortion at incidence, the NASA Rotor 67 with steady pressure distortion, and a triangular prism for turbulence statistics. The results indicated that this method can accurately simulate the performance map, separation transfer and total pressure distributions, compared to the experimental data and Direct Mesh Resolved (DMR) case. The method was then applied to reveal the mechanism of fan influence on intake distortion. It was shown that there are two aspects of such influence: the suction effect of a fan can accelerate the flow in the upstream and directly change its streamline curvature; on the other hand, the recirculating flows can also intensify the turbulence, indirectly increase the mixing process and finally alleviate the distortion. The main flow effect was further investigated in different parameters of fan type, location and distortion size. Results showed that a tip-loaded fan is more effective in suppressing intake separation; a nearer fan to the upstream has more significant reduction of distortion; a greater distortion can be suppressed more. These results demonstrate that a fan can be an essential component for intake distortion control. Further investigations of the results from RANS and LES interpreted the dominance of the influence via main flow or turbulence. It was found that stronger main flow acceleration by a fan can mitigate the inaccuracy of turbulence models. This indicates that for a short intake design, conventional turbulence models may be capable of predicting flow separation.China Scholarship Council, EPSRC Grant EP/L000261/

Ionic Behavior in Highly Concentrated Aqueous Solutions Nanoconfined between Discretely Charged Silicon Surfaces

Through molecular dynamics simulations considering thermal vibration of surface atoms, ionic behaviors in concentrated NaCl solutions confined between discretely charged silicon surfaces have been investigated. The electric double layer structure was found sensitive to the density and distribution of surface charges. Due to the surface charge discreteness, slight charge inversion appeared which depended on the surface charge density, bulk concentration and confinement. In the nanoconfined NaCl solutions differently concentrated from 0.2 M to 4.0 M, the locations of accumulation layers for Na+ and Cl- ions kept stable, but their peak values increased. The higher the concentration was, the more obvious charge inversion appeared. In 4.0 M NaCl solution, Na+ and Cl- ions show obvious alternating layered distributions which may be corresponding to the solidification found in experiments. By changing surface separation, the confinement had a large effect on ionic distributions. As both surfaces approached each other, many ions and water molecules were squeezed out of the confined space. Two adjacent layers in ion or water distribution profiles can be forced to closer to each other and merge together. From ionic hydration analysis, the coordination number of Na+ ions in highly-confined space was much lower than that in the bulk.Comment: 26 pages, 9 figure

Spatiotemporal Variations of Precipitation in China Using Surface Gauge Observations from 1961 to 2016

Long-term precipitation trend is a good indicator of climate and hydrological change. The data from 635 ground stations are used to quantify the temporal trends of precipitation with different intensity in China from 1961 to 2016. These sites are roughly uniformly distributed in the east or west regions of China, while fewer sites exist in the western region. The result shows that precipitation with a rate of 70%. With a 95% confidence level, there is no significant temporal change of annually averaged precipitation in the whole of China. Seasonally, there are no significant temporal changes except for a robust decreasing trend in autumn. Spatially, significant differences in the temporal trends of precipitation are found among various regions. The increasing trend is the largest in Northwest China, and the decreasing trend is the largest in North China. The annually averaged number of precipitation days shows a decreasing trend in all regions except for Northwest China. Regarding precipitation type, the number of light precipitation days shows a robust decreasing trend for almost all regions, while other types show no significant change. Considering the high frequency, the temporal trends of light precipitation could highly explain the temporal variation of the total precipitation amount in China

Spatiotemporal Variations of Precipitation in China Using Surface Gauge Observations from 1961 to 2016

Long-term precipitation trend is a good indicator of climate and hydrological change. The data from 635 ground stations are used to quantify the temporal trends of precipitation with different intensity in China from 1961 to 2016. These sites are roughly uniformly distributed in the east or west regions of China, while fewer sites exist in the western region. The result shows that precipitation with a rate of 70%. With a 95% confidence level, there is no significant temporal change of annually averaged precipitation in the whole of China. Seasonally, there are no significant temporal changes except for a robust decreasing trend in autumn. Spatially, significant differences in the temporal trends of precipitation are found among various regions. The increasing trend is the largest in Northwest China, and the decreasing trend is the largest in North China. The annually averaged number of precipitation days shows a decreasing trend in all regions except for Northwest China. Regarding precipitation type, the number of light precipitation days shows a robust decreasing trend for almost all regions, while other types show no significant change. Considering the high frequency, the temporal trends of light precipitation could highly explain the temporal variation of the total precipitation amount in China