When conifers took flight: a biomechanical evaluation of an imperfect evolutionary takeoff

Paleobiology ◽  
2015 ◽  
Vol 41 (2) ◽  
pp. 205-225 ◽  
Author(s):  
Robert A. Stevenson ◽  
Dennis Evangelista ◽  
Cindy V. Looy
Keyword(s):  
Seed Weight ◽  
High Speed ◽  
Evolutionary Developmental Biology ◽  
Flight Behavior ◽  
Relative Advantage ◽  
Flight Performance ◽  
Dispersal Capacity ◽  
Biomechanical Evaluation ◽  
Variable Morphology ◽  
Insight Into

AbstractManifera talaris, a voltzian conifer from the late early to middle Permian (ca. 270 Ma) of Texas, is the earliest known conifer to produce winged seeds indicative of autorotating flight. In contrast to autorotating seeds and fruits of extant plants, the ones ofM. talarisare exceptional in that they have variable morphology. They bore two wings that produced a range of wing configurations, from seeds with two equal-sized wings to single-winged specimens, via various stages of underdevelopment of one of the wings. To examine the effects of various seed morphologies on aerodynamics and dispersal potential, we studied the flight performance of paper models of three morphotypes: symmetric double-winged, asymmetric double-winged, and single-winged. Using a high-speed camera we identified the mode of descent (plummeting, gliding, autorotation) and quantified descent speed, autorotation frequency, and other flight characteristics. To validate such modeling as an inferential tool, we compared descent of extant analogues (kauri;Agathis australis) with descent of similarly constructed seed models. All three seed morphotypes exhibited autorotating flight behavior. However, double-winged seeds, especially symmetric ones, failed to initiate slow autorotative descent more frequently than single-winged seeds. Even when autorotating, symmetric double-winged seeds descend faster than asymmetric double-winged ones, and descent is roughly twice as fast compared to single-winged seeds. Moreover, the relative advantage that (effectively) single-winged seeds have in slowing descent during autorotation becomes larger as seed weight increases. Hence, the range in seed wing configurations inM. talarisproduced a wide variation in potential dispersal capacity. Overall, our results indicate that the evolutionarily novel autorotating winged seeds must have improved conifer seed dispersal, in a time when animal vectors for dispersion were virtually absent. Because of the range in wing configuration, the early evolution of autorotative flight in conifers was a functionally imperfect one, which provides us insight into the evolutionary developmental biology of autorotative seeds in conifers.

Drivers of Flight Performance of California Condors (Gymnogyps californianus)

2021 ◽  
Author(s):  
Sophie R. Bonner ◽  
Sharon A. Poessel ◽  
Joseph C. Brandt ◽  
Molly T. Astell ◽  
James R. Belthoff ◽  
...  
Keyword(s):  
Flight Behavior ◽  
Flight Performance ◽  
Avian Flight ◽  
Management Plans ◽  
Soaring Flight ◽  
Gymnogyps Californianus ◽  
Social Demographic ◽  
The Relationship ◽  
Effect Of Age ◽  
Insight Into

ABSTRACT Flight behavior of soaring birds depends on a complex array of physiological, social, demographic, and environmental factors. California Condors (Gymnogyps californianus) rely on thermal and orographic updrafts to subsidize extended bouts of soaring flight, and their soaring flight performance is expected to vary in response to environmental variation and, potentially, with experience. We collected 6298 flight tracks described by high-frequency GPS telemetry data from five birds ranging in age from 1 to 19 yr old and followed over 32 d in summer 2016. Using these data, we tested the hypothesis that climb rate, an indicator of flight performance, would be related to the topographic and meteorological variables the bird experienced, and also to its age. Climb rate was greater when condors were flying in faster winds and during environmental conditions that were conducive to updraft development. However, we found no effect of age on climb rate. Although many of these relationships were expected based on flight theory, the lack of an effect of age was unexpected. Our work expands understanding of the relationship condors have with the environment, and it also suggests the potential for as-yet unexplored complexity to this relationship. As such, this study provides insight into avian flight behavior and, because flight performance influences bird behavior and exposure to anthropogenic risk, it has potential consequences for development of conservation management plans.

scholarly journals Address of the President Sir Henry Dale, C.B.E., at the Anniversary Meeting, 1 December 1941

1942 ◽  
Vol 179 (978) ◽  
pp. 233-260 ◽  
Keyword(s):  
Technical College ◽  
High Speed ◽  
Large Scale ◽  
Electrical Engineering ◽  
The United States ◽  
The Past ◽  
Pure Mathematics ◽  
Symbolic Structure ◽  
The Church ◽  
Insight Into

This is the first occasion on which I have had the great honour of addressing the Royal Society on this anniversary of its foundation. According to custom, I begin with brief mention of those whom death has taken from our Fellowship during the past year, and whose memories we honour. Alfred Young (1873-1940), distinguished for his contributions to pure mathematics, was half brother to another of our Fellows, Sydney Young, a chemist of eminence. Alfred Young had an insight into the symbolic structure and manipulation of algebra, which gave him a special place among his mathematical contemporaries. After a successful career at Cambridge he entered the Church, and passed his later years in the country rectory of Birdbrook, Essex. His devotion to mathematics continued, however, throughout his life, and he published a steady stream of work in the branch of algebra which he had invented, and named ‘quantitative substitutional analysis’. He lived to see his methods adopted by Weyl in his quantum mechanics and spectroscopy. He was elected to our Fellowship in 1934. With the death of Miles Walker (1868-1941) the Society loses a pioneer in large-scale electrical engineering. Walker was a man of wide interests. He was trained first for the law, and even followed its practice for a period. Later he studied electrical engineering under Sylvanus Thompson at the Finsbury Technical College and became his assistant for several years. Thereafter, encouraged by Thompson, he entered St John’s College, Cambridge, with a scholarship, and graduated with 1st Class Honours in both the Natural Sciences and the Engineering Tripos. Having entered the service of the British Westinghouse Company, he was sent by them to the United States of America to study electrical engineering with the parent company in Pittsburgh. On his return to England he became their leading designer of high-speed electrical generators

The Mechanical Design of Large Turbogenerators

1987 ◽  
Vol 201 (2) ◽  
pp. 91-103
Author(s):  
B A Marlow
Keyword(s):  
High Speed ◽  
Mechanical Design ◽  
Rotating Machinery ◽  
Design Problems ◽  
Detail Design ◽  
Insight Into

Experience shows that the reliability of large turbogenerators depends substantially on the quality of detail design, particularly the quality of the mechanical design. In addition to the design problems common to all high-speed rotating machinery, the mechanical design of generators must take account of certain electrical requirements. This paper gives an insight into the detail mechanical design of large turbogenerators paying particular attention to the interaction of electrical requirements on the mechanical design.

CAN INFRASTRUCTURE DEVELOPMENT ALLEVIATE MULTIDIMENSIONAL POVERTY? — EVIDENCE FROM CHINA

2021 ◽  
pp. 1-34
Author(s):  
YONGBO GE ◽  
YUEXIAO ZHU ◽  
WENQIANG ZHANG ◽  
XIAORAN KONG
Keyword(s):  
Poverty Alleviation ◽  
Capital Accumulation ◽  
High Speed ◽  
Large Scale ◽  
Multidimensional Poverty ◽  
Infrastructure Development ◽  
Public Infrastructure ◽  
Regional Heterogeneity ◽  
The Impact ◽  
Insight Into

We investigate the impact of the construction of large-scale high-speed railways (HSRs) on regional multidimensional poverty in China. We find that the opening of HSRs can reduce this poverty indicator. This association is robust to a series of checks. Regarding the mechanisms, the opening of HSRs can improve regional accessibility, enhance local tourism, increase labor mobility and promote human capital accumulation, which alleviates multidimensional poverty. Further research indicates the regional heterogeneity of the effect. This research supplements poverty alleviation theory from the perspective of public infrastructure and offers insight into how multidimensional poverty arises and how it can be alleviated.

Reliability Analysis

2020 ◽  
pp. 1-44
Author(s):  
Cherry Bhargava
Keyword(s):  
High Speed ◽  
Manufacturing Industry ◽  
Low Cost ◽  
Operating Performance ◽  
Operating Time ◽  
Electronic System ◽  
Health Condition ◽  
Operating Characteristics ◽  
Integrated Technique ◽  
Insight Into

As the integration of components are increasing from VLSI to ULSI level. This may lead to damage of electronic system because each component has its own operating characteristics and conditions. So, health prognostic techniques are used that comprise a deep insight into failure cause and effects of all the components individually as well as an integrated technique. It will raise alarm, in case health condition, of the components drift from the desired outcomes. From toy to satellite and sand to silicon, the major key constraint of designing and manufacturing industry are towards enhanced operating performance at less operating time. As the technology advances towards high-speed and low-cost gadgets, reliability becomes a challenging issue.

scholarly journals Effects of Feather Lice on Flight Behavior of Male Barn Swallows (Hirundo Rustica)

The Auk ◽  
2002 ◽  
Vol 119 (1) ◽  
pp. 213-216 ◽  
Author(s):  
A. Barbosa ◽  
S. Merino ◽  
Fde Lope ◽  
A. P. Møller
Keyword(s):  
Parasite Load ◽  
Hirundo Rustica ◽  
Flight Behavior ◽  
Flight Performance ◽  
Wingbeat Frequency ◽  
Feather Lice ◽  
Locomotory Performance ◽  
Flight Parameters ◽  
Barn Swallows ◽  
Foraging Flight

Abstract Parasites may affect host behavior in a number of ways, including their locomotory performance. We investigated whether the number of holes produced by the feather louse (Myrsidea rustica) affected flight behavior in adult male Barn Swallows (Hirundo rustica) by video-taping flight performance of individuals during escape and level flight. Percentage of time spent flapping during foraging flight was positively related to number of holes, but not to other flight parameters such as wingbeat frequency. These results suggest indirect effects of feather lice on host performance that must be considered together with effects of thermoregulation and feather breakage. This is the first report of an effect of parasite load on flight behavior.

Observation on Solid Propellant Ignition Using High Speed Camera: The Effect of Hot Wire Position on the Combustion Flame Contour

2014 ◽  
Vol 71 (2) ◽  
Author(s):  
Wan Khairuddin Wan Ali ◽  
Ang Kiang Long ◽  
Mohammad Nazri Mohd. Jaafar
Keyword(s):  
Solid Propellant ◽  
High Speed ◽  
Flame Structure ◽  
Combustion Process ◽  
Ignition Process ◽  
High Speed Camera ◽  
Hot Wire ◽  
Composite Propellant ◽  
Burning Behavior ◽  
Insight Into

This paper reports on the discovery of unique flame structure of a composite propellant sample under hot wire ignition. The entire combustion process at atmospheric pressure condition was recorded using a high speed camera. Three hot wire orientations were chosen in this experiment for examining their effects on the propellant burning behavior. The results show that the wire orientations are crucial in propellant combustion process, as different flame patterns were observed when the hot wire orientation was altered. This paper provides an important insight into this specific ignition process that can be useful for researchers in the aerospace industry for better design and more realistic simulation results in ignition control.

A new method of high-speed cellular protein separation and insight into subcellular compartmentalization of proteins

2011 ◽  
Vol 400 (3) ◽  
pp. 767-775 ◽  
Author(s):  
Evelyn Png ◽  
WanWen Lan ◽  
Melisa Lazaroo ◽  
Silin Chen ◽  
Lei Zhou ◽  
...  
Keyword(s):  
Protein Separation ◽  
High Speed ◽  
Cellular Protein ◽  
New Method ◽  
Subcellular Compartmentalization ◽  
Insight Into

A Method for Integrating Form Errors Into Geometric Tolerance Analysis

2005 ◽  
Author(s):  
Robert Scott Pierce ◽  
David Rosen
Keyword(s):  
Manufacturing Process ◽  
High Speed ◽  
Tolerance Analysis ◽  
Analysis Model ◽  
Geometric Tolerance ◽  
Form Errors ◽  
Product Function ◽  
Component Models ◽  
Insight Into

In this research we describe a computer-aided approach to geometric tolerance analysis for assemblies and mechanisms. This new tolerance analysis method is based on the “generate-and-test” approach. A series of as-manufactured component models are generated within a NURBS-based solid modeling environment. These models reflect errors in component geometry that are characteristic of the manufacturing processes used to produce the components. The effects of different manufacturing process errors on product function is tested by simulating the assembly of these imperfect-form component models and measuring geometric attributes of the assembly that correspond to product functionality. A tolerance analysis model is constructed by generating-and-testing a sequence of component variants that represent a range of manufacturing process capabilities. The generate-and-test approach to tolerance analysis is demonstrated using a case study that is based on a high-speed stapling mechanism. As-manufactured models that correspond to two different levels of manufacturing precision are generated and assembly between groups of components with different precision levels is simulated. Misalignment angles that correspond to functionality of the stapling mechanism are measured at the end of each simulation. The results of these simulations are used to build a tolerance analysis model and to select a set of geometric form and orientation tolerances for the mechanism components. It is found that this generate-and-test approach yields insight into the interactions between individual surface tolerances that would not be gained using more traditional tolerance analysis methods.

Exploratory Studies on the Control of High-Speed Flows With Magnetogasdynamics

2002 ◽  
Author(s):  
Datta V. Gaitonde
Keyword(s):  
Flow Control ◽  
High Speed ◽  
Three Dimensional ◽  
Experimental Investigations ◽  
Control Mechanisms ◽  
Ground Testing ◽  
Simulation Efficiency ◽  
The Status ◽  
Physical Phenomena ◽  
Insight Into

Magnetogasdynamics (MGD) has the potential to lift many of the constraints presently inhibiting sustained hypersonic flight and affordable access to space. Given the difficulty of ground-testing under the expected harsh conditions, numerical methods can provide insight into the physical phenomena, and thus complement experimental investigations in the development of future concepts. This paper describes the status of an effort to develop a high-fidelity, fully three-dimensional method to explore MGD flow control in complex configurations. The theoretical model includes several non-ideal effects and takes recourse to a blend of first principles and phenomenological approaches to enhance simulation efficiency. Boundary conditions are summarized and sample verification exercises are presented. Exploratory calculations on a reentry vehicle and flow-through scramjet flowpath with MGD-bypass demonstrate the versatility of the approach and yield insight into dominant flow control mechanisms.

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