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"Wing, T"
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Finding the Loch Ness Monster: Left-Wing Authoritarianism in the United States
by
Conway, Lucian Gideon
,
Houck, Shannon C.
,
Gornick, Laura Janelle
in
Attitude measures
,
Attitudes
,
Authoritarianism
2018
Although past research suggests authoritarianism may be a uniquely right-wing phenomenon, the present two studies tested the hypothesis that authoritarianism exists in both right-wing and left-wing contexts in essentially equal degrees. Across two studies, university (n = 475) and Mechanical Turk (n = 298) participants completed either the RWA (right-wing authoritarianism) scale or a newly developed (and parallel) LWA (left-wing authoritarianism) scale. Participants further completed measurements of ideology and three domain-specific scales: prejudice, dogmatism, and attitude strength. Findings from both studies lend support to an authoritarianism symmetry hypothesis: Significant positive correlations emerged between LWA and measurements of liberalism, prejudice, dogmatism, and attitude strength. These results largely paralleled those correlating RWA with identical conservative-focused measurements, and an overall effect-size measurement showed LWA was similarly related to those constructs (compared to RWA) in both Study 1 and Study 2. Taken together, these studies provide evidence that LWA may be a viable construct in ordinary U.S. samples.
Journal Article
Laminar post-stall wakes of tapered swept wings
2023
While tapered swept wings are widely used, the influence of taper on their post-stall wake characteristics remains largely unexplored. To address this issue, we conduct an extensive study using direct numerical simulations to characterize the wing taper and sweep effects on laminar separated wakes. We analyse flows behind NACA 0015 cross-sectional profile wings at post-stall angles of attack $\\alpha =14^\\circ$–$22^\\circ$ with taper ratios $\\lambda =0.27$–$1$, leading-edge sweep angles $0^\\circ$–$50^\\circ$ and semi aspect ratios $sAR =1$ and $2$ at a mean-chord-based Reynolds number of $600$. Tapered wings have smaller tip chord length, which generates a weaker tip vortex, and attenuates inboard downwash. This results in the development of unsteadiness over a large portion of the wingspan at high angles of attack. For tapered wings with backward-swept leading edges, unsteadiness emerges near the wing tip. On the other hand, wings with forward-swept trailing edges are shown to concentrate wake-shedding structures near the wing root. For highly swept untapered wings, the wake is steady, while unsteady shedding vortices appear near the tip for tapered wings with high leading-edge sweep angles. For such wings, larger wake oscillations emerge near the root as the taper ratio decreases. While the combination of taper and sweep increases flow unsteadiness, we find that tapered swept wings have more enhanced aerodynamic performance than untapered and unswept wings, exhibiting higher time-averaged lift and lift-to-drag ratio. The current findings shed light on the fundamental aspects of flow separation over tapered wings in the absence of turbulent flow effects.
Journal Article
Enhancing tip vortices to improve the lift production through shear layers in flapping-wing flow control
by
Jin, Bruce Ruishu
,
Young, John
,
Lai, Joseph C.S.
in
Aerodynamic coefficients
,
Angle of attack
,
Blowing
2024
Flow control of a low-aspect-ratio flat-plate heaving wing at an average angle of attack of $10^{\\circ }$ by a steady-blowing jet is numerically studied by using a feedback immersed boundary–lattice Boltzmann method. Blowing jets at the leading edge, mid-chord and trailing edge are considered. The wing enjoys the highest lift production with the trailing-edge downstream blowing jet, which improves the average lift by 50.0 % at $Re = 1000$ and 22.9 % at $Re = 5000$ through the enhancement of the tip vortex circulation caused by the increase in the mass flux of the shear layer at the wing tips. This increase in mass flux decreases as $Re$ increases from 1000 to 5000 due to its self-limiting mechanism. A mid-chord vertical blowing jet induces a middle vortex which enhances the lift production but the enhancement is smaller than that of trailing-edge downstream blowing jet. Other jet arrangements do not significantly increase the lift coefficient, but the mid-chord upstream blowing jet experiences a significant reduction in the drag coefficient, leading to an increase of 50.6 % in the average lift-to-drag ratio. The effectiveness of the flow control is not significantly affected by the aspect ratio.
Journal Article
European and American Extreme Right Groups and the Internet
2013,2016
How do right-wing extremist organizations throughout the world use the Internet as a tool for communication and recruitment? What is its role in identity-building within radical right-wing groups and how do they use the Internet to set their agenda, build contacts, spread their ideology and encourage mobilization? This important contribution to the field of Internet politics adopts a social movement perspective to address and examine these important questions. Conducting a comparative content analysis of more than 500 extreme right organizational web sites from France, Germany, Italy, Spain, the United Kingdom and the United States, it offers an overview of the Internet communication activities of these groups and systematically maps and analyses the links and structure of the virtual communities of the extreme right. Based on reports from the daily press the book presents a protest event analysis of right wing groups' mobilisation and action strategies, relating them to their online practices. In doing so it exposes the new challenges and opportunities the Internet presents to the groups themselves and the societies in which they exist.
Detachment of leading-edge vortex enhances wake capture force production
2024
During stroke reversals, insect wings interact with their own wake flow from the preceding half-stroke, resulting in an unsteady aerodynamic mechanism known as ‘wing–wake interaction’ or ‘wake capture’. To better elucidate this mechanism, we numerically solved the incompressible Navier–Stokes equations at Reynolds numbers $10^2$ and $10^3$. Simulations were conducted for wing planforms defined using the beta function distribution with varying aspect ratios ($AR=2\\unicode{x2013}6$) and radial centroid locations ($\\hat {r}_1=0.4\\unicode{x2013}0.6$), whilst employing representative normal hovering kinematics. The wake development from the considered flapping wing planforms was investigated, and the wake capture contribution to aerodynamic force production was quantified by comparing the force generation between the fifth and first stroke cycles at multiple sections along the wingspan. Our results revealed that on the inboard wing region experiencing an attached leading-edge vortex (LEV) structure, wing–wake interaction is dominated by an unsteady downwash effect, resulting in a reduction in local force production. However, in regions closer to the wingtip experiencing detachment of the LEV, wing–wake interaction is dominated by an unsteady upwash effect, leading to an increase in local force production. Consequently, the global wake capture force production is controlled by the extent of LEV detachment, which primarily increases with the increase of wing aspect ratio. This suggests that for normal hovering flapping wings, the typical loss in translational force production due to wingtip stall is partially mitigated by wake capture effects.
Journal Article
Efficiency of Lift Production in Flapping and Gliding Flight of Swifts
by
Bomphrey, Richard J.
,
Henningsson, Per
,
Hedenström, Anders
in
Aerodynamics
,
Angle of attack
,
Animal behavior
2014
Many flying animals use both flapping and gliding flight as part of their routine behaviour. These two kinematic patterns impose conflicting requirements on wing design for aerodynamic efficiency and, in the absence of extreme morphing, wings cannot be optimised for both flight modes. In gliding flight, the wing experiences uniform incident flow and the optimal shape is a high aspect ratio wing with an elliptical planform. In flapping flight, on the other hand, the wing tip travels faster than the root, creating a spanwise velocity gradient. To compensate, the optimal wing shape should taper towards the tip (reducing the local chord) and/or twist from root to tip (reducing local angle of attack). We hypothesised that, if a bird is limited in its ability to morph its wings and adapt its wing shape to suit both flight modes, then a preference towards flapping flight optimization will be expected since this is the most energetically demanding flight mode. We tested this by studying a well-known flap-gliding species, the common swift, by measuring the wakes generated by two birds, one in gliding and one in flapping flight in a wind tunnel. We calculated span efficiency, the efficiency of lift production, and found that the flapping swift had consistently higher span efficiency than the gliding swift. This supports our hypothesis and suggests that even though swifts have been shown previously to increase their lift-to-drag ratio substantially when gliding, the wing morphology is tuned to be more aerodynamically efficient in generating lift during flapping. Since body drag can be assumed to be similar for both flapping and gliding, it follows that the higher total drag in flapping flight compared with gliding flight is primarily a consequence of an increase in wing profile drag due to the flapping motion, exceeding the reduction in induced drag.
Journal Article
Selective bactericidal activity of nanopatterned superhydrophobic cicada Psaltoda claripennis wing surfaces
by
Crawford, Russell J.
,
Truong, Vi Khanh
,
Webb, Hayden K.
in
Animals
,
antibacterial properties
,
Antimicrobial agents
2013
The nanopattern on the surface of Clanger cicada (
Psaltoda claripennis
) wings represents the first example of a new class of biomaterials that can kill bacteria on contact based solely on its physical surface structure. As such, they provide a model for the development of novel functional surfaces that possess an increased resistance to bacterial contamination and infection. Their effectiveness against a wide spectrum of bacteria, however, is yet to be established. Here, the bactericidal properties of the wings were tested against several bacterial species, possessing a range of combinations of morphology and cell wall type. The tested species were primarily pathogens, and included
Bacillus subtilis
,
Branhamella catarrhalis
,
Escherichia coli
,
Planococcus maritimus
,
Pseudomonas aeruginosa
,
Pseudomonas fluorescens
, and
Staphylococcus aureus
. The wings were found to consistently kill Gram-negative cells (i.e.,
B
.
catarrhalis
,
E
.
coli
,
P
.
aeruginosa
, and
P
.
fluorescens
), while Gram-positive cells (
B
.
subtilis
,
P
.
maritimus
, and
S
.
aureus
) remained resistant. The morphology of the cells did not appear to play any role in determining cell susceptibility. The bactericidal activity of the wing was also found to be quite efficient; 6.1 ± 1.5 × 10
6
P
.
aeruginosa
cells in suspension were inactivated per square centimeter of wing surface after 30-min incubation. These findings demonstrate the potential for the development of selective bactericidal surfaces incorporating cicada wing nanopatterns into the design.
Journal Article
Dove: A biomimetic flapping-wing micro air vehicle
2018
This paper describes the design and development of the Dove, a flapping-wing micro air
vehicle (FWMAV), which was developed in Northwestern Polytechnical University. FWMAVs have
attracted international attentions since the past two decades. Since some achievements
have been obtained, such as the capability of supporting an air vehicle to fly, our
research goal was to design an FWMAV that has the ability to accomplish a task. Main
investigations were presented in this paper, including the flexible wing design, the
flapping mechanism design, and the on-board avionics development. The current Dove has a
mass of 220 g, a wingspan of 50 cm, and the ability of operating fully autonomously,
flying lasts half an hour, and transmitting live stabilized color video to a ground
station over 4 km away.
Journal Article
COLIBRI: A hovering flapping twin-wing robot
2017
This paper describes the results of a six-year project aiming at designing and constructing a flapping twin-wing robot of the size of hummingbird (Colibri in French) capable of hovering. Our prototype has a total mass of 22 g, a wing span of 21 cm and a flapping frequency of 22 Hz; it is actively stabilized in pitch and roll by changing the wing camber with a mechanism known as wing twist modulation. The proposed design of wing twist modulation effectively alters the mean lift vector with respect to the center of gravity by reorganization of the airflow. This mechanism is modulated by an onboard control board which calculates the corrective feedback control signals through a closed-loop PD controller in order to stabilize the robot. Currently, there is no control on the yaw axis which is passively stable, and the vertical position is controlled manually by tuning the flapping frequency. The paper describes the recent evolution of the various sub-systems: the wings, the flapping mechanism, the generation of control torques, the avionics and the PD control. The robot has demonstrated successful hovering flights with an on-board battery for the flight autonomy of 15–20 s.
Journal Article
The ideology of the extreme right
2002,2013,2000
Though the extreme right was not particularly successful in the 1999 European elections, it continues to be a major factor in the politics of Western Europe. This book, newly available in paperback, provides a comprehensive and detailed analysis of the extreme right in the Netherlands (Centrumdemocraten, Centrumpartij'86), Belgium (Vlaams Blok) and Germany (Die Republikaner, Deutsche Volksunion). On the basis of original research - using party literature - the author concludes that though individual parties might stress different issues, the extreme right party family does share a core ideology of nationalism, xenophobia, welfare chauvinism, and law and order. The author's research and conclusions clearly have broader implications for the study of the extreme right phenomenon and party ideology in general, and the book should be of interest to anyone studying or researching in the areas of European politics, political ideologies, political parties, extremism, racism or nationalism.