427 research outputs found
Gliding swifts attain laminar flow over rough wings
No full textSwifts are among the most aerodynamically refined gliding birds. However, the overlapping vanes and protruding shafts of their primary feathers make swift wings remarkably rough for their size. Wing roughness height is 1–2% of chord length on the upper surface—10,000 times rougher than sailplane wings. Sailplanes depend on extreme wing smoothness to increase the area of laminar flow on the wing surface and minimize drag for extended glides. To understand why the swift does not rely on smooth wings, we used a stethoscope to map laminar flow over preserved wings in a low-turbulence wind tunnel. By combining laminar area, lift, and drag measurements, we show that average area of laminar flow on swift wings is 69% (n = 3; std 13%) of their total area during glides that maximize flight distance and duration—similar to high-performance sailplanes. Our aerodynamic analysis indicates that swifts attain laminar flow over their rough wings because their wing size is comparable to the distance the air travels (after a roughness-induced perturbation) before it transitions from laminar to turbulent. To interpret the function of swift wing roughness, we simulated its effect on smooth model wings using physical models. This manipulation shows that laminar flow is reduced and drag increased at high speeds. At the speeds at which swifts cruise, however, swift-like roughness prolongs laminar flow and reduces drag. This feature gives small birds with rudimentary wings an edge during the evolution of glide performance
Author Gender Representation at Audio Engineering Conferences - An Anonymised Dataset
No full textThis repository contains the author gender dataset (as a comma-delimited .csv file) associated with the paper entitled 'The Impact of Gender on Conference Authorship in Audio Engineering: Analysis Using a New Data Collection Method', published in the IEEE Transactions Special Issue on Increasing the Socio-Cultural Diversity of Electrical and Computer Engineering and Related Fields. Available at: dx.doi.org/10.1109/TE.2018.2814613. Please cite both the paper and dataset if used. Visualisation is available at: http://tibbakoi/github.io/aesgender.
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The dataset was produced using a novel method which used self-identified pronouns, therefore allowing for as many groups as necessary to describe the population.
A list of authors was generated from conference proceedings.
An email was sent to each author to acquire their pronoun.
If no email was available/no response was received, a pronoun was acquired from a biography.
If no biography was available, a pronoun was inferred from traditional gender markers and gender presentation.
If no gender marker/photograph was available, the entry was labelled as 'Information Unavailable'. For brevity, the label 'Unknown' is used in the paper.
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The columns in the dataset are as follows:
ID: unique identifier of entry
Pronoun: pronoun of entry
Position (abs): numerical absolute position within author list for entry
Position (relative): relative position within author list for entry (either First, Last, or Middle)
Single/multi-author: whether the publication for that entry has a single author or has multiple authors (single author publications are excluded from author position analysis)
Conference: Full conference name of entry
Topic: Topic of conference of entry, taken from conference name
Year: Year of conference of entry
Type: Type of publication for that entry as listed on the online conference proceedings
Grouped Type: Grouping of publication types for that entry for easier analysis due to inconsistencies in online conference proceedings (groups are: workshop, poster, paper, panel, keynote, invited speaker, invited paper, demo)
Inc. for author pos?: True/False as to whether to include the entry for analysis over author position (included types are: paper, invited paper, poster as these have meaningful author orders)
Inc. for single/multi-author?: True/False as to whether to include the entry for analysis over single/multi author (includes types are: paper, invited paper, poster as these have meaningful author orders)
Invited paper status: Grouping of the types to allow statistical analysis over invited vs non-invited types (invited types are: invited speaker, invited paper, keynote, panel. Non-invited types are: poster, paper, demo, workshop)
NB: Some grouping of the data is required as online conference proceedings are not always consistent (Column 10). Some labelling of the data is required to determine which entries to include in certain types of analysis (Columns 11-13).
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This dataset is distributed in the hopes that it will prove useful under the Creative Commons Attribution 4.0, with no warranty; or the implied warranty of merchantability or fitness for a particular problem.
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Dataset curated by: Kat Young and Michael Lovedee-Turner at the Audio Lab, Dept. of Electronic Engineering, University of York.
Contact: [email protected], [email protected]</p
Kat River revisited
No full textThere is a paucity of oral-history works on Kat River. Likewise, although various histories of Kat River/Stockenstrom exist, few have focused on the forced removals of Stockenstrom coloured people in the 1980s, the effects of displacement on them, and their involvement in current land claims issues. This dissertation seeks to redress these lacunae and provide information from "the underside" on the Kat River Rebellion of 1851-1853. In order to accomplish this, between 2011 and 2016 the author interviewed, with their consent, people of Khoikhoi descent in Kat River, recording, transcribing and analysing the interviews. The interviews, which range from conversations with male and female subsistence farmers and lay preachers to activists - such as the late Manie Loots, aka James Stewart - are set in the broader context of a selective Kat River history from 1829 to the present. Vagrancy legislation during the historical period is discussed; showing the link between pauperism, vagrancy, and colonial perceptions of disease such as leprosy, which was often associated with "loose" women. It is argued that the above perceptions, together with fear, led to the targeting of women and lepers during the attack on Fort Armstrong in 1852. Despite attempts to marginalise them, it was found that both colonial women, including rebels, and women in present-day Kat River exercised, and continue to exercise, remarkable agency. This thesis also reassesses the ideological bases of the Kat River Settlement, arguing that they were cultivation and militarism, with the latter exemplified in the Kat River settlers' service in frontier wars. Further, it found that neo-Marxist theories of commoning can shed light on the etiology of the Kat River Rebellion, and that people, whose access to their commons or other rights is restricted or denied, become radicalised. It was also found that, although their dispossession from Kat River took place in the 1980s, the interviewees, who all demonstrated strong ties to the land on which they grew up, still feel the effects of it, their all-consuming aim being the recognition of their land claims and the restoration of their titles
Pressure from particle image velocimetry for convective flows: A Taylor\u92s hypothesis approach
No full textTaylors hypothesis is often applied in turbulent flow analysis to map temporal information into spatial information. Recent efforts in deriving pressure from particle image velocimetry (PIV) have proposed multiple approaches, each with its own weakness and strength. Application of Taylors hypothesis allows us to counter the weakness of an Eulerian approach that is described by de Kat & van Oudheusden (2012 Exp. Fluids 52 1089106). We build on the findings of de Kat & Ganapathisubramani (2013 Meas. Sci. Technol. 24 024002) and look in more detail into different ways of obtaining estimates for convection velocity on the determination of pressure from PIV using Taylor\u92s hypothesis. We also look at the influence of the omission of viscous terms. Results appear to indicate that pressure can indeed be obtained from PIV data in turbulent convective flows using the Taylors hypothesis approach, where there are no other methods to determine pressure. A more local estimate of convection velocity results in a pressure field that has less obvious defects. Other than a change in reference pressure for the pressure evaluation, inclusion or omission of the viscous terms appears to not have a significant effect
Black and white newspaper from The Compass about the Kit Kat Club. Part 2.
No full textA group of twelve men in suits are posed standing and sitting for photograph. Continued from part 2 L-R: Joseph Pike, Sid Jones, Steve Penney, Jim Moore, Bill Finn, George Soper. Scanned newspaper article about the Kit Kat Club. This group played cards on Saturday nights. Newspaper clipping from Poole's personal collection
Social memory and ethnic identity: ancient Greek drama performances as commemorative ceremonies
No full textThis thesis is an ethnographic account of ancient Greek drama performances that take place in contemporary Greece. It illuminates an aspect of them that has not been taken into account until today: it treats them as commemorative ceremonies that produce, reproduce, and transmit social memory. The interrelation and interdependence between social memory and ethnic identity construction processes are analysed and it is shown that ancient drama performances, due to specific characteristics, constitute something more than mere theatrical events (as they are defined within the Western tradition). These performances, convey, sustain, and transmit from one generation to the next, perceptions of a glorious culture of the past, and become, for its creators and spectators, occasions for celebrating and remembering their ethnic past
Instantaneous planar pressure determination from PIV in turbulent flow
No full textThis paper deals with the determination of instantaneous planar pressure fields from velocity data obtained by particle image velocimetry (PIV) in turbulent flow. The operating principles of pressure determination using a Eulerian or a Lagrangian approach are described together with theoretical considerations on its expected performance. These considerations are verified by a performance assessment on a synthetic flow field. Based on these results, guidelines regarding the temporal and spatial resolution required are proposed. The interrogation window size needs to be 5 times smaller than the flow structures and the acquisition frequency needs to be 10 times higher than the corresponding flow frequency (e.g. Eulerian time scales for the Eulerian approach). To further assess the experimental viability of the pressure evaluation methods, stereoscopic PIV and tomographic PIV experiments on a square cylinder flow (ReD = 9,500) were performed, employing surface pressure data for validation. The experimental results were found to support the proposed guidelines.Aerospace Engineerin
Rethinking mythology in Greek museums through contemporary culture
No full textThis thesis investigates the character with which Greek mythology, one of the most durable manifestations of ancient Greek heritage, survives in the perception of contemporary Greeks, and the role that Greek museums do and could play in this. The starting point for this investigation is the appraisal of Greek mythology as an ideological creation of ancient Greece that bears pan-human and diachronie intellectual and cultural potency and, as such, constitutes a significant interpretative tool for the contemporary Greek individual. More specifically, this thesis reconsiders the relationships between Greek mythology, Greek museums and Greek people, using as a bridge contemporary Greek art. It does so in three main chapters, which investigate and analyze different parameters of this nexus of relationships. Greek mythology’s adaptations by contemporary Greek society are also explored in an attempt to establish the dominant contemporary meanings of Greek mythology. Then, the relation of a specific cultural manifestation of contemporary Greek society, that of contemporary art, to Greek mythology is extensively analyzed through a series of interviews that were conducted exclusively for this thesis. In these interviews, contemporary Greek musicians, authors and visual artists speak of the position that Greek mythology possess (or does not possess) in their artistic expression, and discuss the intellectual and cultural significance that Greek myths retain for contemporary society and people. From these investigations, two antithetic poles emerge. On the one hand, there is the trivializing way in which Greek society deals with its myths through their exploitation, for example, for commercial or nationalist purposes. On the other hand, there is the sensitivity with which my interviewees pored over Greek myths, enabling them to emerge full of dynamism, and illuminating them as ever-active negotiators of life and human nature. Thus, contemporary art is identified as a powerful conveyor of mythology’s potency for the contemporary individual. Next, the position of Greek archaeological museums, as major official institutions that do, or could, represent and safeguard Greek mythology is explored and critically assessed. It emerges that Greek museums are rather unconcerned with Greek mythology’s representation and communication and thus, confirm that Greek mythology is a dead and irrelevant representative of a glorious, yet remote and strange, ancient civilization
My island village : cultural mapping and conservation of a cultural landscape, the island of Kat O
No full textKat O is a secluded island in Tai Pang Wan, located in the north-eastern coast of Hong Kong, used to have a vibrant population of several thousand villagers of land-based Hakka and sea-based Tanka descent. Its unique geological shape and rich environmental resources offered a natural safe haven for fishing. This tranquil island has fostered an old fishing village with more than 300 years of history. The long history has formed a rich cultural landscape and shaped their distinctive appearance and characteristics with a mix of different types of values. However, the fast changes of modern era have threatened the sustainability and the irreplaceable heritage resources on the island.
Kat O is a good example of an organically evolved cultural landscape in Hong Kong, and one that is transiting from a continuing landscape to a relict landscape. It is an area of precious natural resources and rich traditional culture. Unique community and their way of life was formed and evolved in the past 300 years, but is threatened by contemporary modernization in recent decades.
Today, the Kat O community is facing a serious population decline, with only around 50 elderly people remaining, and the village settlements on the island are expected to be abandoned in the near future. Already, the gradual abandonment can be seen in the increasing number of empty and dilapidating village houses. The current conservation approach on Kat O generally focuses on the natural aspect such as ecological and geological, where the associated cultural elements are being neglected.
Given that there is no specific publication that viewed Kat O as a cultural landscape to investigate the relationship between people and their natural environment comprehensively, the author feels an urgency to identify and reveal the culture character of Kat O, in particular the tangible and intangible character-defining elements embodied in the way of life of the Kat O people.published_or_final_versionConservationMasterMaster of Science in Conservatio
Dynamic pitching effect on a laminar separation bubble
No full textThe unsteady effect of a periodic pitching motion on the characteristic of a laminar separation bubble on the suction side of a SD7003 aerofoil is investigated by means of time-resolved planar and tomographic particle image velocimetry. The measurements provide information on the separation, transition and vortex roll-up onset as well as the spanwise distribution of vortical structures, for both the dynamic pitching between 4° and 8° and corresponding cases at a static pitch angle. During pitching, a clear hysteresis behaviour is observed for the vortex roll-up position and shedding frequency, showing a strongly delayed recovery of the shear layer with respect to the steady aerofoil case. The development of the shear layer transition exhibits initially 2D Kelvin–Helmholtz rollers that are interrupted, forming ?-shaped rollers, which eventually evolve into 3D arch-shaped hairpin structures. The 3D analysis of undulated rollers allowed the determination of the rollers streamwise spatial separation for both static and pitching aerofoil case
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