Latitudinal Variation of Wing: Thorax Size Ratio and Wing-Aspect Ratio in Drosophila melanogaster

Evolution ◽  
1998 ◽  
Vol 52 (5) ◽  
pp. 1353 ◽  
Author(s):  
Ricardo B. R. Azevedo ◽  
Avis C. James ◽  
Jennie McCabe ◽  
L. Partridge
Keyword(s):  
Drosophila Melanogaster ◽  
Aspect Ratio ◽  
Size Ratio ◽  
Latitudinal Variation ◽  
Wing Aspect Ratio

scholarly journals LATITUDINAL VARIATION OF WING:THORAX SIZE RATIO AND WING-ASPECT RATIO IN DROSOPHILA MELANOGASTER

Evolution ◽  
1998 ◽  
Vol 52 (5) ◽  
pp. 1353-1362 ◽  
Author(s):  
Ricardo B. R. Azevedo ◽  
Avis C. James ◽  
Jennie McCabe ◽  
L. Partridge
Keyword(s):  
Drosophila Melanogaster ◽  
Aspect Ratio ◽  
Size Ratio ◽  
Latitudinal Variation ◽  
Wing Aspect Ratio

Numerical Study of Winglet at Low Reynolds Numbers

2013 ◽  
Author(s):  
Sina Pooladsanj ◽  
Mehran Tadjfar
Keyword(s):  
Aspect Ratio ◽  
Flow Field ◽  
Vortex Flow ◽  
Numerical Study ◽  
Reynolds Numbers ◽  
Flow Zone ◽  
Low Reynolds Numbers ◽  
Structured Grid ◽  
Flow Field Characteristics ◽  
Wing Aspect Ratio

A numerical study has been performed to evaluate the aerodynamics coefficients of a winglet in the range of Reynolds numbers below 30,000. In this study some parameters on winglet design have been considered. The effect of winglet-tip airfoil thickness has been investigated on aerodynamics coefficients. In order to explore this effect, two different airfoils (NACA0002 and NACA0012) were employed at the winglet-tip. The influence of varying the winglet connection angle to the wing on aerodynamics coefficients and flow field characteristics in the vortex flow zone such as; circulation magnitude and vorticity magnitude in the vortex core have been studied. Six connection angles including 20°, 30°, 40°, 50°, 60° and 70° have been studied. Negative values of these angles have also been considered. In addition, the effect of changing wing aspect ratio on aerodynamics coefficients has been investigated. To solve the flow field around the studied geometry a fully structured grid was used which consists of 84 blocks.

LATITUDINAL VARIATION FOR TWO ENZYME LOCI AND AN INVERSION POLYMORPHISM IN DROSOPHILA MELANOGASTER FROM CENTRAL AND SOUTH AMERICA

Evolution ◽  
2000 ◽  
Vol 54 (1) ◽  
pp. 201 ◽  
Author(s):  
Jan Van ‘t Land ◽  
Willem F. Van Putten ◽  
Haroldo Villarroel ◽  
Albert Kamping ◽  
Wilke Van Delden
Keyword(s):  
Drosophila Melanogaster ◽  
South America ◽  
Inversion Polymorphism ◽  
Latitudinal Variation ◽  
Enzyme Loci

Abstract TP90: Effect of Smoking on Morphological Variables for Ruptured and Unruptured Intracranial Aneurysms

Stroke ◽  
2013 ◽  
Vol 44 (suppl_1) ◽  
Author(s):  
Ning Lin ◽  
Allen L Ho ◽  
Arthur L Day ◽  
Rose Du
Keyword(s):  
Aspect Ratio ◽  
Intracranial Aneurysms ◽  
Smoking Status ◽  
Aneurysm Rupture ◽  
Size Ratio ◽  
Morphological Parameters ◽  
Vascular Architecture ◽  
Ruptured Aneurysms ◽  
Unruptured Intracranial Aneurysms ◽  
Morphological Variables

Introduction: Management of unruptured intracranial aneurysms remains controversial in neurosurgery. The contribution of morphological parameters has been gradually included in the treatment paradigm. Smoking is associated with increased risk of cerebral aneurysm formation and rupture, but the effect of smoking on morphological features of an aneurysm is unclear. We present a large sample of aneurysms that were assessed using morphological variables to investigate how smoking status affects the parameters associated with aneurysm rupture. Methods: Pre-operative CT angiograms (CTA) were evaluated with 3D Slicer© to generate three-dimensional models of the aneurysms and surrounding vascular architecture. Morphological parameters examined in each model included aneurysm volume, size, aspect ratio, aneurysm angle, flow angle, size ratio, and parent-daughter angle. Univariate and multivariate statistical analyses were performed to determine statistical significance. Results: From 2006-2010, 114 ruptured and 89 unruptured aneurysms were treated in a single institution, including 72 anterior communicating artery aneurysms, 79 middle cerebral artery aneurysms, and 52 internal carotid artery aneurysms. Ruptured aneurysms were associated with greater aspect ratio and size ratio, larger aneurysm angle, and smaller parent-daughter angle (p<0.05). While no difference in aneurysm angle and parent-daughter angle was observed based on smoking status, ruptured aneurysms in smokers are more likely to be smaller in size, have narrower neck diameters, and possess larger aspect ratios (p<0.05) when compared to ruptured aneurysms in nonsmokers. Multivariate logistic regression revealed aspect ratio was the strongest parameter associated with aneurysm rupture in patients who smoke after adjusting for demographic and other clinical risk factors. Conclusion: Aspect ratio, aneurysm angle, and parent-daughter angle have a greater association with aneurysm rupture than size. Smoking status does not affect parameters related to the vascular architecture (i.e. aneurysm angle and parent-daughter angle), but is associated with increased aspect ratio and smaller size in ruptured aneurysms.

Non-linear aeroelastic response of high aspect-ratio wings in the frequency domain

2017 ◽  
Vol 121 (1240) ◽  
pp. 858-876 ◽  
Author(s):  
F. Afonso ◽  
J. Vale ◽  
É. Oliveira ◽  
F. Lau ◽  
A. Suleman
Keyword(s):  
Aspect Ratio ◽  
Current Trend ◽  
Commercial Aircraft ◽  
Aeroelastic Response ◽  
Flutter Speed ◽  
Wing Model ◽  
Induced Drag ◽  
Non Linear ◽  
Flutter Boundary ◽  
Wing Aspect Ratio

ABSTRACTA current trend in the aeronautic industry is to increase the wing aspect ratio to enhance aerodynamic efficiency by reducing the induced drag and thus reduce fuel consumption. Despite the associated benefits of a large aspect ratio, such as higher lift-to-drag ratios and range, commercial aircraft usually have a relatively low aspect ratio. This is partially explained by the fact that the wing becomes more flexible with increasing aspect ratio and thus more prone to large deflections, which can cause aeroelastic instability problems such as flutter. In this work, an aeroelastic study is conducted on a rectangular wing model of 20 m span and variable chord for a low subsonic speed condition to evaluate the differences between linear and non-linear static aeroelastic responses. Comparisons between linear and non-linear displacements, natural frequencies and flutter boundary are performed. An in-house non-linear aeroelastic framework was employed for this purpose. In this work, the influence of the aspect ratio and geometric non-linearity (highly deformed states) is assessed in terms of aeroelastic performance parameters: flutter speed and divergence speed. A nearly linear correlation of flutter speed difference (relative to linear analysis results) with vertical-tip displacement difference is observed. The flutter and divergence speeds vary substantially as the wing aspect ratio increases, and the divergence speeds always remain above the flutter speed. Furthermore, the flutter mechanism was observed to change as the wing chord is decreased.

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