The mobility of charge-carriers in dielectric liquids

This thesis describes work carried out in the Department of Applied Physics, Durham University, from October 1964 to September 1967. The work was a continuation of investigations, under the supervision of Dr. M.J. Mo rant, into the electrical properties of dielectric liquids. The work of Sletten in 1959 and that of Morant and Kahan in 1964 has shown that dissolved oxygen has a marked effect on the breakdown strength and the conductivity of a typical dielectric liquid, n-hexane. The present investigation shows that the reduced breakdown strength and increased conductivity observed on de-gassing hexane may not be explained in terms of an increase in carrier mobility. The mobility of photo-injected carriers in highly de-gassed hexane is found to be no greater than the mobility of the same carriers in air-saturated liquid. Further, no increase of mobility with applied field is observed in the de-gassed liquid for fields up to 140 KV/cm; nor is there any indication, under these conditions, of the existence of an additional 'fast' carrier. The variation of the injected current with both the applied field and the degree of oxidation of the cathode, however, indicates that the 'oxygen effect' referred to above is an electrode, surface phenomenon and not a property of the liquid itself. The current transients from which the mobility determinations were made are not exactly of the form predicted by simple theory. This and other anomalous observations indicate a strong interaction between the charge-carriers and the neutral liquid molecules. Such an interaction is consistent with self-trapping of the injected carriers by polarization of the surrounding medium. Suggestions for further work on the identification of the charge-carriers in dielectric liquids and on the factors affecting breakdown and conductivity are made in the text

Development of a carbon-based polymer composite product for efficient recovery of crude oil in oil spill environments: report of researcher exchange March 2019

The India-UK Water Centre (IUKWC) promotes cooperation and collaboration between the complementary priorities of NERC-MoES water security research. This document reports on the Junior Researcher Exchange program conducted at the Indian Institute of Science (IISc) in Bangalore, India, during the month of March 2019. The theme of the Research Exchange; transforming science into management catchment solutions, brought into sharp focus the issues surrounding laboratory based results and scaled up solutions to catchment management. Awareness of this unfortunate reality inspired this exchange to attempt to produce output that works on simple, scalable principles for removing crude oil from water. The lead researcher Mr Jonathan Bloor from the University of Plymouth in the UK worked with host researcher, Dr Sai Siva Gorthi and his lead postdoctoral researcher Dr Vikram S. to develop polymer based composite products for the recovery of crude oil. The outcome of the exchange resulted in a prototype Graphene Oxide (GO) Aerogel foam that can separate crude oil and water via simple gravity method. Additional output also involved the rapid prototyping of electrospinning nanofibre membranes to enhance the selectivity and mechanical strength of the foam. This report is intended for members of the IUKWC Open Network and water security stakeholders

A survey of partial differential equations in geometric design

YesComputer aided geometric design is an area where the improvement of surface generation techniques is an everlasting demand since faster and more accurate geometric models are required. Traditional methods for generating surfaces were initially mainly based upon interpolation algorithms. Recently, partial differential equations (PDE) were introduced as a valuable tool for geometric modelling since they offer a number of features from which these areas can benefit. This work summarises the uses given to PDE surfaces as a surface generation technique togethe

CMTM6 maintains the expression of PD-L1 and regulates anti-tumour immunity

Cancer cells exploit the expression of the programmed death-1 (PD-1) ligand 1 (PD-L1) to subvert T-cell-mediated immunosurveillance. The success of therapies that disrupt PD-L1-mediated tumour tolerance has highlighted the need to understand the molecular regulation of PD-L1 expression1. Here we identify the uncharacterized protein CMTM6 as a critical regulator of PD-L1 in a broad range of cancer cells, by using a genome-wide CRISPR–Cas9 screen. CMTM6 is a ubiquitously expressed protein that binds PD-L1 and maintains its cell surface expression. CMTM6 is not required for PD-L1 maturation but co-localizes with PD-L1 at the plasma membrane and in recycling endosomes, where it prevents PD-L1 from being targeted for lysosome-mediated degradation. Using a quantitative approach to profile the entire plasma membrane proteome, we find that CMTM6 displays specificity for PD-L1. Notably, CMTM6 depletion decreases PD-L1 without compromising cell surface expression of MHC class I. CMTM6 depletion, via the reduction of PD-L1, significantly alleviates the suppression of tumour-specific T cell activity in vitro and in vivo. These findings provide insights into the biology of PD-L1 regulation, identify a previously unrecognized master regulator of this critical immune checkpoint and highlight a potential therapeutic target to overcome immune evasion by tumour cells.M.L.B. is supported by a Cancer Research UK Clinician Scientist Fellowship (C53779/A20097), Addenbrooke’s Charitable Trust award and NIHR fellowship. P.J.L. is supported by a Wellcome Trust PRF (101835/Z/13/Z) and work in the Lehner laboratory is supported by NHSBT, NIHR Cambridge BRC, a Wellcome Trust Strategic Award to CIMR, and the Addenbrooke’s Charitable Trust M.A.D. is supported by a Senior Leukaemia Foundation Australia Fellowship and work in the Dawson laboratory is supported by the NHMRC (Grants 1085015, 1106444 and 1106447) Cancer Council Victoria and Leukaemia Foundation Australia. Cancer Research UK (C53779/A20097

A collaborative platform for integrating and optimising Computational Fluid Dynamics analysis requests

A Virtual Integration Platform (VIP) is described which provides support for the integration of Computer-Aided Design (CAD) and Computational Fluid Dynamics (CFD) analysis tools into an environment that supports the use of these tools in a distributed collaborative manner. The VIP has evolved through previous EU research conducted within the VRShips-ROPAX 2000 (VRShips) project and the current version discussed here was developed predominantly within the VIRTUE project but also within the SAFEDOR project. The VIP is described with respect to the support it provides to designers and analysts in coordinating and optimising CFD analysis requests. Two case studies are provided that illustrate the application of the VIP within HSVA: the use of a panel code for the evaluation of geometry variations in order to improve propeller efficiency; and, the use of a dedicated maritime RANS code (FreSCo) to improve the wake distribution for the VIRTUE tanker. A discussion is included detailing the background, application and results from the use of the VIP within these two case studies as well as how the platform was of benefit during the development and a consideration of how it can benefit HSVA in the future

An investigation into the perspectives of providers and learners on MOOC accessibility

An effective open eLearning environment should consider the target learner’s abilities, learning goals, where learning takes place, and which specific device(s) the learner uses. MOOC platforms struggle to take these factors into account and typically are not accessible, inhibiting access to environments that are intended to be open to all. A series of research initiatives are described that are intended to benefit MOOC providers in achieving greater accessibility and disabled learners to improve their lifelong learning and re-skilling. In this paper, we first outline the rationale, the research questions, and the methodology. The research approach includes interviews, online surveys and a MOOC accessibility audit; we also include factors such the risk management of the research programme and ethical considerations when conducting research with vulnerable learners. Preliminary results are presented from interviews with providers and experts and from analysis of surveys of learners. Finally, we outline the future research opportunities. This paper is framed within the context of the Doctoral Consortium organised at the TEEM'17 conference

Social Effects in Science: Modelling Agents for a Better Scientific Practice

Science is a fundamental human activity and we trust its results because it has several error-correcting mechanisms. Its is subject to experimental tests that are replicated by independent parts. Given the huge amount of information available, scientists have to rely on the reports of others. This makes it possible for social effects to influence the scientific community. Here, an Opinion Dynamics agent model is proposed to describe this situation. The influence of Nature through experiments is described as an external field that acts on the experimental agents. We will see that the retirement of old scientists can be fundamental in the acceptance of a new theory. We will also investigate the interplay between social influence and observations. This will allow us to gain insight in the problem of when social effects can have negligible effects in the conclusions of a scientific community and when we should worry about them.Comment: 14 pages, 5 figure

What young people want from health-related online resources: a focus group study

The growth of the Internet as an information source about health, particularly amongst young people, is well established. The aim of this study was to explore young people's perceptions and experiences of engaging with health-related online content, particularly through social media websites. Between February and July 2011 nine focus groups were facilitated across Scotland with young people aged between 14 and 18 years. Health-related user-generated content seems to be appreciated by young people as a useful, if not always trustworthy, source of accounts of other people's experiences. The reliability and quality of both user-generated content and official factual content about health appear to be concerns for young people, and they employ specialised strategies for negotiating both areas of the online environment. Young people's engagement with health online is a dynamic area for research. Their perceptions and experiences of health-related content seem based on their wider familiarity with the online environment and, as the online environment develops, so too do young people's strategies and conventions for accessing it