scholarly journals A mechanical piston action may assist pelvic–pectoral fin antagonism in tree-climbing fish

2017 ◽  
Vol 98 (8) ◽  
pp. 2121-2131 ◽  
Author(s):  
Adhityo Wicaksono ◽  
Saifullah Hidayat ◽  
Bambang Retnoaji ◽  
Adolfo Rivero-Müller ◽  
Parvez Alam
Keyword(s):  
Finite Element ◽  
Energy Saving ◽  
Finite Element Simulations ◽  
Morphological Investigation ◽  
Pectoral Fin ◽  
Terrestrial Locomotion ◽  
Pectoral Fins ◽  
Biomimetic Robots ◽  
The Relationship ◽  
Pelvic Fin

In this research, we compared the anatomy and biomechanics of two species of mudskipper vs an aquatic sandgoby in view of terrestrial locomotion. Of particular interest was the relationship (if any) of pectoral fin movement with pelvic fin movement. We show that the pelvic fins of the terrestrial mudskippers studied herein, are retractable and move antagonistically with the pectoral fins. The pelvic fin of the sandgoby studied here is contrarily non-retractable and drags on any underlying substrate that the sandgoby tries to crawl across. We find that the pelvic and pectoral fin muscles of all fish are separated, but that the pectoral fins of the mudskipper species have bulkier radial muscles than the sandgoby. By coupling a detailed morphological investigation of pectoral-pelvic fins musculature with finite element simulations, we find that unlike sandgobies, the mudskipper species are able to mechanically push the pelvic fins downward as pectoral fins retract. This allows for an instant movement of pelvic fins during the pectoral fin backward stroke and as such the pelvic fins stabilize mudskippers through Stefan attachment of their pelvic fins. This mechanism seems to be efficient and energy saving and we hypothesize that the piston-like action might benefit pelvic–pectoral fin antagonism by facilitating a mechanical down-thrust. Our research on the biomechanics of tree-climbing fish provides ideas and greater potential for the development of energetically more efficient systems of ambulation in biomimetic robots.

Quebecius quebecensis (Whiteaves), a porolepiform crossopterygian (Pisces) from the Late Devonian of Quebec, Canada

1987 ◽  
Vol 24 (12) ◽  
pp. 2351-2361 ◽  
Author(s):  
Hans-Peter Schultze ◽  
Marius Arsenault
Keyword(s):  
Ventral Side ◽  
The Body ◽  
Late Devonian ◽  
Pectoral Fin ◽  
Pectoral Fins ◽  
Median Fins ◽  
Pelvic Fin

Quebecius quebecensis (Whiteaves 1889) is a porolepiform crossopterygian related to Glyptolepis. A large nariodal, a large tabular, a separate intertemporal, and a large fused nasosupraorbital are features of Quebecius that characterize it as a porolepiform. The small size of the operculum, median extrascapular larger than the lateral one, small lower squamosals, and deep maxilla are additional features separating Quebecius from Glyptolepis. As in Glyptolepis, the median fins are not lobed. The pectoral fin possesses a long fleshy lobe. The internal, ventral side of the broadly based pelvic fin suggests that the internal axis has shifted towards the body. Pectoral fins with a long fleshy lobe are a common feature of porolepiforms, but lobed bases in the pelvic and unpaired fins are a feature found in Holoptychius, and not in Glyptolepis and Quebecius. Quebecius quebecensis is conspecific with Quebecius williamsi Schultze 1973, mistakenly described as an onychodont crossopterygian.

Dynamic Analysis of a Robotic Fish Propelled by Flexible Folding Pectoral Fins

Robotica ◽  
2019 ◽  
Vol 38 (4) ◽  
pp. 699-718 ◽  
Author(s):  
Van Anh Pham ◽  
Tan Tien Nguyen ◽  
Byung Ryong Lee ◽  
Tuong Quan Vo
Keyword(s):  
Power Stroke ◽  
Swimming Velocity ◽  
Force Model ◽  
Flexible Joints ◽  
Pectoral Fin ◽  
Pectoral Fins ◽  
Recovery Stroke ◽  
Turning Radius ◽  
Relationship Of ◽  
The Relationship

SUMMARYBiological fish can create high forward swimming speed due to change of thrust/drag area of pectoral fins between power stroke and recovery stroke in rowing mode. In this paper, we proposed a novel type of folding pectoral fins for the fish robot, which provides a simple approach in generating effective thrust only through one degree of freedom of fin actuator. Its structure consists of two elemental fin panels for each pectoral fin that connects to a hinge base through the flexible joints. The Morison force model is adopted to discover the relationship of the dynamic interaction between fin panels and surrounding fluid. An experimental platform for the robot motion using the pectoral fin with different flexible joints was built to validate the proposed design. The results express that the performance of swimming velocity and turning radius of the robot are enhanced effectively. The forward swimming velocity can reach 0.231 m/s (0.58 BL/s) at the frequency near 0.75 Hz. By comparison, we found an accord between the proposed dynamic model and the experimental behavior of the robot. The attained results can be used to design controllers and optimize performances of the robot propelled by the folding pectoral fins.

Research on the Adjustable LAVAL Nozzle during Pneumatic Conveying

2009 ◽  
Vol 87-88 ◽  
pp. 474-480
Author(s):  
Dong Mei Jiao
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Energy Saving ◽  
Laval Nozzle ◽  
Pneumatic Conveying ◽  
Element Analysis ◽  
Output Displacement ◽  
Input And Output ◽  
The Relationship

The relationship between the input and output (displacement of adjusting lever and air flow) of adjustable LAVAL nozzle is deduced. In the pneumatic conveying condition, finite element analysis to adjustable LAVAL nozzle is simulated, and its steady-flow effect is proved. Experiments show the adjustable LAVAL nozzle is energy-saving, can improve the quality of conveyed material, and reduce percentage of damage.

scholarly journals Energy-saving mechanisms in walking and running

1991 ◽  
Vol 160 (1) ◽  
pp. 55-69 ◽  
Author(s):  
R. M. Alexander
Keyword(s):  
Energy Saving ◽  
Mechanical Performance ◽  
Elastic Strain Energy ◽  
Metabolic Energy ◽  
Elastic Recoil ◽  
Work Requirements ◽  
Terrestrial Locomotion ◽  
Speed Parameter ◽  
The Relationship ◽  
Positive Work

Energy can be saved in terrestrial locomotion in many different ways. The maximum shortening speeds (Vmax) of the muscles can be adjusted to their optimum values for the tasks required of them. The moments exerted by the muscles at different joints can be adjusted to keep the ground force in line with the leg so that muscles do not work against each other. The joints of the legs can be kept as straight as possible, minimizing muscle forces and work requirements. Walking gaits should be selected at low Froude numbers (a dimensionless speed parameter) and running gaits at high Froude numbers. Tendon and other springs can be used to store elastic strain energy and to return it by elastic recoil. This paper aims to show how these energy-saving mechanisms work and to what extent mammals exploit them. Arguments based on our rather limited knowledge of the relationship between the mechanical performance of muscle and its metabolic energy consumption are used throughout. They suggest that muscles that are optimally adapted for their tasks in running should do positive work with constant efficiency.

scholarly journals Molecular mechanisms underlying the exceptional adaptations of batoid fins

2015 ◽  
Vol 112 (52) ◽  
pp. 15940-15945 ◽  
Author(s):  
Tetsuya Nakamura ◽  
Jeff Klomp ◽  
Joyce Pieretti ◽  
Igor Schneider ◽  
Andrew R. Gehrke ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Integration Site ◽  
The Body ◽  
Pectoral Fin ◽  
Pectoral Fins ◽  
Bony Fishes ◽  
Genetic Module ◽  
Fin Development ◽  
Pelvic Fin

Extreme novelties in the shape and size of paired fins are exemplified by extinct and extant cartilaginous and bony fishes. Pectoral fins of skates and rays, such as the little skate (Batoid, Leucoraja erinacea), show a strikingly unique morphology where the pectoral fin extends anteriorly to ultimately fuse with the head. This results in a morphology that essentially surrounds the body and is associated with the evolution of novel swimming mechanisms in the group. In an approach that extends from RNA sequencing to in situ hybridization to functional assays, we show that anterior and posterior portions of the pectoral fin have different genetic underpinnings: canonical genes of appendage development control posterior fin development via an apical ectodermal ridge (AER), whereas an alternative Homeobox (Hox)–Fibroblast growth factor (Fgf)–Wingless type MMTV integration site family (Wnt) genetic module in the anterior region creates an AER-like structure that drives anterior fin expansion. Finally, we show that GLI family zinc finger 3 (Gli3), which is an anterior repressor of tetrapod digits, is expressed in the posterior half of the pectoral fin of skate, shark, and zebrafish but in the anterior side of the pelvic fin. Taken together, these data point to both highly derived and deeply ancestral patterns of gene expression in skate pectoral fins, shedding light on the molecular mechanisms behind the evolution of novel fin morphologies.

scholarly journals Teratogenic processes in an embryo without gills and low yolk absorption of Zapteryx brevirostris (Elasmobranchii: Rhinobatidae)

2015 ◽  
Vol 63 (4) ◽  
pp. 497-500 ◽  
Author(s):  
Wanessa Priscila David do Carmo ◽  
Luís Fernando Fávaro
Keyword(s):  
Common Species ◽  
Pectoral Fin ◽  
First Report ◽  
Pectoral Fins ◽  
Nutritional Problem ◽  
Yolk Absorption ◽  
Pelvic Fin

Abstract This is the first report of morphological anomaly in embryos of Zapteryx brevirostris (Lesser guitarfish), a very common species in Brazil. The gills were absent, and the pectoral fins were not fully formed nor were they completely fused to the head. They were asymmetrical, with the larger left pectoral fin projecting more toward the head (almost at the height of the eyes). The pelvic fin was absent, making sexing impossible. The cause of the morphological deformity is uncertain, although a nutritional problem of the embryo is evoked.

Analysis of magnetic force and dynamic characteristic for non-contact permanent magnet linear drive device

2020 ◽  
Vol 64 (1-4) ◽  
pp. 1337-1345
Author(s):  
Chuan Zhao ◽  
Feng Sun ◽  
Junjie Jin ◽  
Mingwei Bo ◽  
Fangchao Xu ◽  
...  
Keyword(s):  
Finite Element ◽  
Permanent Magnet ◽  
Dynamic Characteristic ◽  
Driving Force ◽  
Magnetic Circuit ◽  
Response Speed ◽  
Computation Method ◽  
Element Analysis ◽  
Element Simulation ◽  
The Relationship

This paper proposes a computation method using the equivalent magnetic circuit to analyze the driving force for the non-contact permanent magnet linear drive system. In this device, the magnetic driving force is related to the rotation angle of driving wheels. The relationship is verified by finite element analysis and measuring experiments. The result of finite element simulation is in good agreement with the model established by the equivalent magnetic circuit. Then experiments of displacement control are carried out to test the dynamic characteristic of this system. The controller of the system adopts the combination control of displacement and angle. The results indicate that the system has good performance in steady-state error and response speed, while the maximum overshoot needs to be reduced.

Development and evaluation of trans-Amadi groundwater parameters: The integration of finite element techniques

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Finite Element ◽  
Polynomial Regression ◽  
Nitrate Concentration ◽  
Strong Relationship ◽  
Total Iron ◽  
Coefficient Of Determination ◽  
Port Harcourt ◽  
Polynomial Expression ◽  
The Relationship ◽  
Best Fit

Mathematical model was developed and evaluated to monitor and predict the groundwater characteristics of Trans-amadi region in Port Harcourt City. In this research three major components were considered such as chloride, total iron and nitrate concentration as well as the polynomial expression on the behavious on the concentration of each component was determined in terms of the equation of the best fit as well as the square root of the curve. The relationship between nitrate and distance traveled by Nitrate concentration by the model is given as Pc = 0.003x2 - 0.451x + 14.91with coefficient of determination, R² = 0.947, Chloride given as Pc = 0.000x2 - 0.071x + 2.343, R² = 0.951while that of Total Iron is given as Pc = 2E-05x2 - 0.003x + 0.110, R² = 0.930. All these show a strong relationship as established by Polynomial Regression Model. The finite element techniques are found useful in monitoring, predicting and simulating groundwater characteristics of Trans-amadi as well as the prediction on the variation on the parameters of groundwater with variation in time.

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