341 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
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
Tale of Two Judiths: Queering Judith with the Works of Judith Butler
No full textBiblical texts play a significant role in shaping expectations for behavior based on gender in Western societies. In my queer reading of the Book of Judith, I argue that Judith’s performance of gender is fluid and gender expansive. I use reader-response criticism to interpret Judith in conversation with the works of Judith Butler and Saba Mahmood on gender performativity, drag, and agency. This queer reading of Judith provides representation of gender expansiveness in biblical texts and explores queer possibilities in Judith as a way to challenge and subvert a patriarchal, heterosexist gender binary
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
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