Contributors: Corkery, Simon James
... Wind gusts can be highly detrimental to the performance of fixed wing aircraft. At low flight speeds, gusts transverse to the lifting surfaces can cause massive changes to the angle of incidence, fluctuations in lift and drag, and result in flight instability. This may be catastrophic for small drones, and hazardous for larger aircraft during take-off and landing. Onboard gust sensing and counter-control is a promising solution, but requires a model of the wing-gust interaction. The problem is that only simple linear models such as Küssner’s theory exist, and the physics of large amplitude wing-gust encounters is unknown. This work is a fundamental study into the physics of such interaction. The aims are to uncover the phenomenon which contribute toward the force response of the wing. In particular, the role of free vortices and added mass are investigated and compared with the conditions modelled within Küssner’s transverse gust theory. Two sets of experiments were conducted using flat plate wing models in a water towing tank. Data was acquired using a combination of Particle Image Velocimetry (PIV), dye flow visualisation, and force measurements. A novel methodology was also developed to isolate added mass effects from standard resolution PIV. The first experiment involved accelerating the plate in translation and angular directions to validate the added mass extraction methodology, and investigate viscous effects on added mass. The experiments successfully demonstrated both the technique, and that the potential flow added mass solution is valid even for viscous and separated flows. For the second experiment, equipment was constructed to facilitate the generation of a ‘sharp edged’ top-hat shaped gust velocity profile in the towing tank. The wing models were towed through this, thereby replicating a wing-gust encounter. Test cases with gust ratios of 0.2, 0.5 and 1.0, as well as Reynolds numbers from 5,000 to 40,000 were conducted. The results showed that Küssner’s model predicted the force response for each encounter surprisingly well, albeit discrepancies emerged at the higher gust ratios. This was attributed to significant leading edge separation as well as deflection and subsequent roll-up of the gust shear layers. For wing-gust encounters it was shown that the force component attributed to added mass in Küssner’s model is not equivalent to that of an accelerating body, rather it can be attributed to the relative advection of gust shear layer vortices. We call this a ‘non-circulatory vortex force’. A second non-circulatory vortex force was additionally proposed, attributed to the generation of free vortices. This was shown to be responsible for the buoyancy and added mass like force, for cases where a flow field is accelerated past a stationary body.
Contributors: Chisholm, Jennifer
... My doctoral research consisted of fourteen months of fieldwork following anti-eviction activity within informal settlements called favelas on public land in Rio de Janeiro. In the dissertation, I make a series of arguments. The first is that despite a lack of scholarly attention post-2016 Olympics, Rio is experiencing its own favela housing rights movement, land rights, and government investment in upgrading projects that deserves academic attention. Implied in the term is a concomitant fight for land rights—both of which are needed to avoid eviction. Secondly, I explain how government officials and others antagonistic to favela housing rights use environmentalist discourse to justify evictions of informal settlements—charging them with being ‘invaders’ that spoil the natural habitat of the city. In response, favela residents have re-appropriated the discourse of environmentalism to position and re-brand themselves as conservationists instead of ‘invaders’ as one of two alternative strategies to avoid eviction. Thirdly, and regarding the second alternative anti-eviction strategy, I explain how those against favela housing rights view favelas as places without culture or history that do not need to be saved from eviction. To subvert this narrative, residents have created favela museums and initiated tourism enterprises to prove that their communities have cultures and histories that are worth preserving. The fourth and fifth arguments correspond to the gender, class, and racial implications of these alternative strategies as interpreted through emotional politics. I argue that women (the predominant demographic in the movement) feel they must justify their leadership positions and participation in the movement by engaging in what I call performative vulnerability. Lastly, I explain how residents interpret the common justifications for favela removal (i.e. environmental destruction, favelas as places without history) as being truly about classism, and to a lesser extent racism. I contend that the general lack of awareness about the role of racism in favela evictions stems from the lingering ambivalence towards racial categorisation and the false belief that Afro-descendants do not face discrimination. This research engages with academic debates on the forced eviction of informal settlements, housing rights versus environmental rights, identity politics, and contributes to the literature on urban land and housing movements.
Research data supporting "Strain mediated bending of InP nanowires through the growth of an asymmetric InAs shell"
Contributors: Greenberg, Yaakov, Kelrich, Alexander, Cohen, Shimon, Kar-Narayan, Sohini, Ritter, Dan, Calahorra, Yonatan
... This data set includes a complete COMSOL simulation file, for the bending of a tapered InP/InAs core-shell structure. Also the manual curvature analysis of a nanowire, based on its TEM is shown.
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Research data supporting "Ultra-Low Cost High-Density Two-Dimensional Visible-Light Optical Interconnects"
Contributors: Bamiedakis, Nikolaos
... This data set relates to the JLT submitted article entitled "Ultra-Low Cost High-Density Two-Dimensional Visible-Light Optical Interconnects"
Data related to the publication: "High-Speed Data Transmission over Flexible Multimode Polymer Waveguides Under Flexure"
Contributors: Bamiedakis, Nikolaos, Shi, Fengyuan, Chu, Daping, Penty, Richard, White, Ian
... Experimental data related to the IEEE Photonics Technology Letters publication entitled: "High-Speed Data Transmission over Flexible Multimode Polymer Waveguides Under Flexure"
The association between supra-physiologic arterial oxygen levels and mortality in critically ill patients: a multi-centre observational cohort study
Contributors: Palmer, E, Post, B, Klapaukh, R, Marra, G, MacCallum, NS, Brealey, D, Ercole, Ari, Jones, A, Watkinson, P, Beale, R
... Rationale There is conflicting evidence on harm related to exposure to supra-physiologic arterial oxygen tensions (hyperoxemia) in critically ill patients. Objectives To examine the association between longitudinal exposure to hyperoxemia and mortality in patients admitted to intensive care units (ICUs) in 5 UK University Hospitals. Methods Retrospective cohort of ICU admissions between 31st January 2014 - 31st December 2018, from the National Institute of Health Research Critical Care Health Informatics Collaborative (CC-HIC). Multivariable logistic regression modelled death in ICU by exposure to hyperoxemia. Measurements Subsets with oxygen exposure windows of 0-1, 0-3, 0-5 and 0-7 days were evaluated, capturing 19,515, 10,525, 6,360 and 4,296 patients, respectively. Hyperoxemia dose was defined as the area between the PaO2 time curve and a boundary of 13.3 kPa (100 mmHg) divided by the hours of potential exposure (24, 72, 120, or 168 hours). For Review Only Main Results An association was found between exposure to hyperoxemia and ICU mortality [odds ratios (95% compatibility intervals); 1.15 (0.95-1.38), p = 0.15; 1.35 (1.04-1.74), p = 0.02; 1.5 (1.07-2.13), p = 0.02; and 1.74 (1.11-2.72), p = 0.02 for exposure windows of 0-1, 0-3, 0-5 and 0-7 days’ duration, respectively. However, a dose-response relationship was not observed. There was no evidence to support a differential effect between hyperoxemia and either a respiratory diagnosis or mechanical ventilation. Conclusions An association between hyperoxemia and mortality was observed in our large, unselected multicenter cohort. The absence of a dose-response relationship weakens causal interpretation. Further experimental research is warranted to elucidate this important question.
Contributors: Bennett, Robert, Smith, Harry, Van Lieshout, Carry, Montebruno, Piero
... This paper describes the process of identifying and coding business partners and partnerships from the population censuses 1851-1911 in England, Wales and Scotland derived from I-CeM to include in the British Business Census of Entrepreneurs (BBCE) data deposit.
Contributors: Bennett, Robert, Montebruno, Piero, Smith, Harry, Van Lieshout, Carry
... This paper extends the reconstructions in WP 9 to identify entrepreneurs 1851-81 at an individual level , where status was not explicitly identified in the censuses. The method developed uses a method of variable logit cut-offs tailored to each occupation code.
Zfp281 (ZBP-99) plays a functionally redundant role with Zfp148 (ZBP-89) during erythroid development.
Contributors: Woo, Andrew J, Patry, Chelsea-Ann A, Ghamari, Alireza, Pregernig, Gabriela, Yuan, Daniel, Zheng, Kangni, Piers, Taylor, Hibbs, Moira, Li, Ji, Fidalgo, Miguel
Contributors: Reisner, Erwin, Creissen, Charles E, Warnan, Julien, Anton Garcia, Daniel, Farre, Yoann, Odobel, Fabrice
... Dye-sensitized photoelectrochemical (DSPEC) cells are an emerging approach to producing solar fuels. Recent development of delafossite CuCrO2 as the p-type semiconductor has enabled H2 generation through the co-assembly of catalyst and dye components. Here, we present a CuCrO2 electrode based on a high surface area inverse opal (IO) architecture with benchmark performance in DSPEC H2 generation. Co-immobilization of a phosphonated diketopyrrolopyrrole (DPP-P) or perylene monoimide (PMI-P) dye with a phosphonated molecular Ni catalyst (NiP) demonstrates the ability of IO-CuCrO2 to photo-generate H2. A highly positive photocurrent onset potential of approximately +0.8 V vs. RHE was achieved with these photocathodes. The DPP-P-based photoelectrodes delivered photocurrents of -18 µA cm-2 and generated 160 ± 24 nmolH! cm-2, whereas the PMI-P-based photocathodes displayed higher photocurrents of -25 µA cm-2 and produced 215 ± 10 nmolH! cm-2 at 0.0 V vs. RHE over the course of 2 h under visible light illumination (100 mW cm-2, AM 1.5G, l > 420 nm, 25 °C). The high performance of the PMI-constructed system is attributed to the well-suited molecular structure and photophysical properties for p-type sensitization. These precious-metal-free photocathodes highlight the benefits of using bespoke IO-CuCrO2 electrodes as well as the important role of molecular dye structure in DSPEC fuel synthesis.