The kinematics and performance of escape responses of the knifefish Xenomystus nigri

1993 ◽  
Vol 71 (1) ◽  
pp. 189-195 ◽  
Author(s):  
M. A. Kasapi ◽  
P. Domenici ◽  
R. W. Blake ◽  
D. Harper
Keyword(s):  
High Speed ◽  
Longitudinal Axis ◽  
The Body ◽  
Maximum Acceleration ◽  
Low Speed ◽  
Average Maximum ◽  
Morphological Specialization ◽  
Escape Responses ◽  
And Performance ◽  
Stage 1

The kinematics and performance of the escape responses of the knifefish Xenomystus nigri, a fish specialized for low-speed, undulatory median-fin propulsion, were recorded by means of high-speed cinematography. Two types of escape were observed, one involving the formation of a C-shape along the longitudinal axis of the fish (stage 1), followed by a slow recoil of the body (single bend); the other (double bend) involved stage 1 followed by a contralateral bend (stage 2). The pectoral fins were extended throughout escapes of both types. The average maximum acceleration for double bend escapes was 127.98 m∙s−2; acceleration was usually greatest in stage 1. In double bend escapes, turning angles for stages 1 and 2 were not correlated. Pitch and roll orientations change during escapes. In stage 1, the average roll and average pitch were linearly correlated, suggesting that roll was partly responsible for establishing pitch. Knifefish achieved high maximum acceleration relative to other fish. Therefore, performance was not compromised by morphological specialization for low-speed swimming; however, a negative correlation of pitch with acceleration in stage 1 suggested that escapes involve a trade-off between acceleration and confusing a predator by changing planar orientation.

The Kinematics and Performance of the Escape Response in the Angelfish (Pterophyllum Eimekei)

1991 ◽  
Vol 156 (1) ◽  
pp. 187-205 ◽  
Author(s):  
PAOLO DOMENICI ◽  
ROBERT W. BLAKE
Keyword(s):  
High Speed ◽  
Maximum Velocity ◽  
Subsequent Stage ◽  
Maximum Acceleration ◽  
Turning Angle ◽  
Time Performance ◽  
Escape Angle ◽  
Escape Responses ◽  
Stage 1 ◽  
Direction Opposite

The kinematics of turning manoeuvres and the distance-time performance in escape responses of startled angelfish (Pterophyllum eimekei) are investigated employing high-speed cinematography (400 Hz). All escape responses observed are C-type fast-starts, in which the fish assumes a C shape at the end of the initial body contraction (stage 1). Kinematic analysis of the subsequent stage (stage 2) allows the response to be classified into two types: single bend (SB), in which the tail does not recoil completely after the formation of the C, and double bend (DB), in which it does. The two types of response have different total escape angles (measured from the subsequent positions of the centre of mass, SB 120.0°; DB 73.3°, P<0.005), different stage 2 turning angles (in the same direction as stage 1 for SB, 11.0°; in the direction opposite to stage 1 for DB, −21.9°: P<0.0005) and different maximum angular velocities in the direction opposite to the initial one (SB −8.08 rad s−1; DB −56.62 rad s−1: P<0.001). There are no significant differences in stage 1 kinematics for the two types of escape. Stage 1 turning angle is linearly correlated to stage 2 turning angle for DB only (P<0.01; r2=0.60) and to total escape angle for both types of response (P<0.0001; r2=0.80). Stage 1 duration is linearly correlated to stage 1 turning angle (P<0.0001; r2=0.83) and to total escape angle (P<0.0001; r2=0.72) for both types of escape. Distance-time performance is also different in the two response types, mainly because of differences in stage 2 (maximum velocity for SB 0.99 ms−1; maximum velocity for DB 1.53 ms−1: maximum acceleration for SB 34.1 ms−2; maximum acceleration for DB 74.7 ms−2: P<0.0001 in both cases). As a result, there are significant differences in the performance throughout the whole response (maximum velocity 1.02 ms−1 and 1.53 ms−1 for SB and DB fast-starts, respectively; maximum acceleration 63.2 ms−2 and 91.9 ms−2 for SB and DB fast-starts, respectively) as well as within a fixed time (0.03 s). Overall, higher distance-time performances associated with smaller angles of turn are found in DB than in SB responses. Comparison with previous studies reveals that angelfish have a good fast-start performance despite specializations for low-speed swimming. In addition, the angelfish turning radius (0.065±0.0063 L, where L is body length; mean±2 S.E.) is lower than that previously reported for any fish.

The C-start escape response ofPolypterus senegalus: bilateral muscle activity and variation during stage 1 and 2

2002 ◽  
Vol 205 (17) ◽  
pp. 2591-2603 ◽  
Author(s):  
Eric D. Tytell ◽  
George V. Lauder
Keyword(s):  
Muscle Activity ◽  
Escape Response ◽  
High Speed ◽  
Wave Speed ◽  
Activity Patterns ◽  
Motor Pattern ◽  
The Body ◽  
Wide Range ◽  
Fast Start ◽  
Stage 1

SUMMARYThe fast-start escape response is the primary reflexive escape mechanism in a wide phylogenetic range of fishes. To add detail to previously reported novel muscle activity patterns during the escape response of the bichir, Polypterus, we analyzed escape kinematics and muscle activity patterns in Polypterus senegalus using high-speed video and electromyography (EMG). Five fish were filmed at 250 Hz while synchronously recording white muscle activity at five sites on both sides of the body simultaneously (10 sites in total). Body wave speed and center of mass velocity, acceleration and curvature were calculated from digitized outlines. Six EMG variables per channel were also measured to characterize the motor pattern. P. senegalus shows a wide range of activity patterns, from very strong responses, in which the head often touched the tail, to very weak responses. This variation in strength is significantly correlated with the stimulus and is mechanically driven by changes in stage 1 muscle activity duration. Besides these changes in duration, the stage 1 muscle activity is unusual because it has strong bilateral activity, although the observed contralateral activity is significantly weaker and shorter in duration than ipsilateral activity. Bilateral activity may stiffen the body, but it does so by a constant amount over the variation we observed; therefore, P. senegalus does not modulate fast-start wave speed by changing body stiffness. Escape responses almost always have stage 2 contralateral muscle activity, often only in the anterior third of the body. The magnitude of the stage 2 activity is the primary predictor of final escape velocity.

scholarly journals Escaping from multiple visual threats: Modulation of escape responses in Pacific staghorn sculpin (Leptocottus armatus).

2021 ◽  
Author(s):  
Hibiki Kimura ◽  
Tilo Pfalzgraff ◽  
Marie Levet ◽  
Yuuki Kawabata ◽  
John F Steffensen ◽  
...  
Keyword(s):  
Visual Stimulus ◽  
Escape Response ◽  
The Body ◽  
Body Motion ◽  
Time Interval ◽  
Time Intervals ◽  
Escape Responses ◽  
Leptocottus Armatus ◽  
Stage 1 ◽  
Staghorn Sculpin

Fish perform rapid escape responses to avoid sudden predatory attacks. During escape responses, fish bend their bodies into a C-shape and quickly turn away from the predator and accelerate. The escape trajectory is determined by the initial turn (Stage 1) and a contralateral bend (Stage 2). Previous studies have used a single threat or model predator as a stimulus. In nature, however, multiple predators may attack from different directions simultaneously or in close succession. It is unknown whether fish are able to change the course of their escape response when startled by multiple stimuli at various time intervals. Pacific staghorn sculpin (Leptocottus armatus) were startled with a left and right visual stimulus in close succession. By varying the timing of the second stimulus, we were able to determine when and how a second stimulus could affect the escape response direction. Four treatments were used: a single visual stimulus (control); or two stimuli coming from opposite sides separated by a 0 ms (simultaneous treatment); a 33 ms; or a 83 ms time interval. The 33 ms and 83 ms time intervals were chosen to occur shortly before and after a predicted 60 ms visual escape latency (i.e. during Stage 1). The 0 ms and 33 ms treatments influenced both the escape trajectory and the Stage 1 turning angle, compared to a single stimulation, whereas the 83 ms treatment had no effect on the escape response. We conclude that Pacific staghorn sculpin can modulate their escape response only between stimulation and the onset of the response, but that escape responses are ballistic after the body motion has started.

Durability Determination of the Bearing Structure of an Open Freight Wagon Body Made of Round Pipes during its Transportation on the Railway Ferry

2019 ◽  
Vol 21 (1) ◽  
pp. 28-34
Author(s):  
Oleksij Fomin ◽  
Juraj Gerlici ◽  
Alyona Lovska ◽  
Kateryna Kravchenko ◽  
Pavlo Prokopenko ◽  
...  
Keyword(s):  
Angular Displacement ◽  
Vertical Direction ◽  
Longitudinal Axis ◽  
The Body ◽  
Maximum Acceleration ◽  
Upper Deck ◽  
International Transport ◽  
The Cost ◽  
New Generation

In order to reduce the cost of designing and manufacturing of the new-generation open wagons, it is proposed to construct their carrying systems from round pipes. In order to exploit the proposed designs of wagons in international rail-water communication, it is assumed that they will be equipped with assemblies for fastening of chain binders. The maximal values of accelerations, as components of dynamic load acting on open wagons, made from round pipes during their transportation on a railway ferry, are determined. It is established that when moving the body in the vertical direction for a wagon located on the upper deck, the maximum acceleration value is 0.84g, with angular displacement relative to the transverse axis for the extreme from the anchor point of the wagon body - is 0.1 g, with angular displacement around the longitudinal axis for the extreme from the bulwark of the body of the wagon - is 0.24g. The conducted researches will enable increased efficiency of operation of open wagons through international transport corridors.

Environmental effects on undulatory locomotion in the American eel Anguilla rostrata: kinematics in water and on land

1998 ◽  
Vol 201 (7) ◽  
pp. 949-961 ◽  
Author(s):  
G. B. Gillis
Keyword(s):  
Muscle Activity ◽  
High Speed ◽  
Activity Patterns ◽  
The Body ◽  
Anguilla Rostrata ◽  
American Eel ◽  
Terrestrial Locomotion ◽  
Average Maximum ◽  
Undulatory Locomotion ◽  
Longitudinal Position

Historically, the study of swimming eels (genus Anguilla) has been integral to our understanding of the mechanics and muscle activity patterns used by fish to propel themselves in the aquatic environment. However, no quantitative kinematic analysis has been reported for these animals. Additionally, eels are known to make transient terrestrial excursions, and in the past it has been presumed (but never tested) that the patterns of undulatory movement used terrestrially are similar to those used during swimming. In this study, high-speed video was used to characterize the kinematic patterns of undulatory locomotion in water and on land in the American eel Anguilla rostrata. During swimming, eels show a nonlinear increase in the amplitude of lateral undulations along their bodies, reaching an average maximum of 0.08L, where L is total length, at the tip of the tail. However, in contrast to previous observations, the most anterior regions of their bodies do not undergo significant undulation. In addition, a temporal lag (typically 10–15 % of an undulatory cycle) exists between maximal flexion and displacement at any given longitudinal position. Swimming speed does not have a consistent effect on this lag or on the stride length (distance moved per tailbeat) of the animal. Speed does have subtle (although statistically insignificant) effects on the patterns of undulatory amplitude and intervertebral flexion along the body. On land, eels also use lateral undulations to propel themselves; however, their entire bodies are typically bent into waves, and the undulatory amplitude at all body positions is significantly greater than during swimming at equivalent speeds. The temporal lag between flexion and displacement seen during swimming is not present during terrestrial locomotion. While eels cannot move forwards as quickly on land as they do in water, they do increase locomotor speed with increasing tailbeat frequency. The clear kinematic distinctions present between aquatic and terrestrial locomotor sequences suggest that eels might be using different axial muscle activity patterns to locomote in the different environments.

Simple mechanisms organise orientation of escape swimming in embryos and hatchling tadpoles of Xenopus laevis

2000 ◽  
Vol 203 (12) ◽  
pp. 1869-1885 ◽  
Author(s):  
A. Roberts ◽  
N.A. Hill ◽  
R. Hicks
Keyword(s):  
Mathematical Model ◽  
Xenopus Laevis ◽  
High Speed ◽  
Three Dimensional ◽  
Longitudinal Axis ◽  
The Body ◽  
Video Recordings ◽  
Stage Of Development ◽  
Physical Features ◽  
Neutrally Buoyant

Many amphibian tadpoles hatch and swim before their inner ears and sense of spatial orientation differentiate. We describe upward and downward swimming responses in hatchling Xenopus laevis tadpoles from stages 32 to 37/38 in which the body rotates about its longitudinal axis. Tadpoles are heavier than water and, if touched while lying on the substratum, they reliably swim upwards, often in a tight spiral. This response has been observed using stroboscopic photography and high-speed video recordings. The sense of the spiral is not fixed for individual tadpoles. In ‘more horizontal swimming’ (i.e. in directions within +/−30 degrees of the horizontal), the tadpoles usually swim belly-down, but this position is not a prerequisite for subsequent upward spiral swimming. Newly hatched tadpoles spend 99 % of their time hanging tail-down from mucus secreted by a cement gland on the head. When suspended in mid-water by a mucus strand, tadpoles from stage 31 to 37/38 tend to swim spirally down when touched on the head and up when touched on the tail. The three-dimensional swimming paths of stage 33/34 tadpoles were plotted using simultaneous video images recorded from the side and from above. Tadpoles spiralled for 70 % of the swimming time, and the probability of spiralling increased to 1 as swim path angles became more vertical. Tadpoles were neutrally buoyant in Percoll/water mixtures at 1.05 g cm(−)(3), in which anaesthetised tadpoles floated belly-down and head-up at 30 degrees. In water, their centre of mass was ventral to the muscles in the yolk mass. A simple mathematical model suggests that the orientation of tadpoles during swimming is governed by the action of two torques, one of which raises the head (i.e. increases the pitch) and the other rotates (rolls) the body. Consequently, tadpoles (i) swim belly-down when the body is approximately horizontal because the body is ballasted by dense yolk, and (ii) swim spirally at more vertical orientations when the ballasting no longer stabilises orientation. Measurements in tethered tadpoles show that dorsal body flexion, which could produce a dorsal pitch torque, is present during swimming and increases with tailbeat frequency. We discuss how much of the tadpole's behaviour can be explained by our mathematical model and suggest that, at this stage of development, oriented swimming responses may depend on simple touch reflexes, the organisation of the muscles and physical features of the body, rather than on vestibular reflexes.

Fast-start Performance and Body Form in Seven Species of Teleost Fish

1978 ◽  
Vol 74 (1) ◽  
pp. 211-226 ◽  
Author(s):  
P. W. WEBB
Keyword(s):  
Lepomis Macrochirus ◽  
Maximum Velocity ◽  
The Body ◽  
Salmo Gairdneri ◽  
Maximum Acceleration ◽  
Body Form ◽  
Fast Start ◽  
Major Variable ◽  
And Performance ◽  
Depth Enhancement

Fast-start kinematics and performance were determined for Etheostoma caeruleum, Cottus cognatus, Notropis cornutus, Lepomis macrochirus, Perca flavescens, Salmo gairdneri and a hybrid Esox sp. at an acclimation and test temperature of 15 °C. Normal three-stage kinematic patterns were observed for all species. Fast-start movements were similar in all species, except Lepomis, which had slightly higher amplitudes than expected for its length. The duration of kinematic stages was a major variable among the seven species but was a linear function of length. Acceleration rates were not functions of size. Maximum acceleration rates ranged from 22-7 to 39-5 m. s−2 with mean rates from 6.1 to 12.3 m.s−2 averaged to the completion of kinematic stage 2. Maximum velocity and distance covered in each fast-start stage varied among species but were related to length. Fast-start performance depended primarily on compromise between muscle mass as a percentage of body mass, and lateral body and fin profile. Optimal profiles provide large depth distant from the centre of mass to maximize thrust, and anterior depth enhancement to minimize recoil. The body form of Lepomis is considered optimal for multiple swimming modes.

scholarly journals Numerical Analysis of Aerodynamic Characteristics of a of High-Speed Car With Movable Bodywork Elements

2015 ◽  
Vol 62 (4) ◽  
pp. 451-476 ◽  
Author(s):  
Tomasz Janson ◽  
Janusz Piechna
Keyword(s):  
Numerical Analysis ◽  
High Speed ◽  
Transient Flow ◽  
Aerodynamic Drag ◽  
Position Angle ◽  
Aerodynamic Characteristics ◽  
The Body ◽  
Ansys Fluent ◽  
Drag Forces ◽  
And Performance

Abstract This paper presents the results of numerical analysis of aerodynamic characteristics of a sports car equipped with movable aerodynamic elements. The effects of size, shape, position, angle of inclination of the moving flaps on the aerodynamic downforce and aerodynamic drag forces acting on the vehicle were investigated. The calculations were performed with the help of the ANSYS-Fluent CFD software. The transient flow of incompressible fluid around the car body with moving flaps, with modeled turbulence (model Spalart-Allmaras or SAS), was simulated. The paper presents examples of effective flap configuration, and the example of configuration which does not generate aerodynamic downforce. One compares the change in the forces generated at different angles of flap opening, pressure distribution, and visualization of streamlines around the body. There are shown the physical reasons for the observed abnormal characteristics of some flap configurations. The results of calculations are presented in the form of pressure contours, pathlines, and force changes in the function of the angle of flap rotation. There is also presented estimated practical suitability of particular flap configurations for controlling the high-speed car stability and performance.

scholarly journals UJI PRESTASI MESIN PENDINGIN KOMPRESI UAP YANG MENGGUNAKAN REFRIGERAN R22 DENGAN METODE PENGUJIAN AKTUAL DAN SIMULASI

2018 ◽  
Vol 3 (2) ◽  
pp. 73-82
Author(s):  
Audri Deacy Cappenberg ◽  
Haris Ramadan
Keyword(s):  
High Speed ◽  
Cooling System ◽  
Simulation Software ◽  
Vapor Compression ◽  
Low Speed ◽  
Performance Factors ◽  
Thermodynamic Simulations ◽  
And Performance ◽  
Vapor Compression Cooling ◽  
Different Characteristics

AbstrakSistem pengkondisian udara yang mengatur temperatur dan  kelembaban udara dalam ruangan, dalam pengoperasiannya membutuhkan refrigeran yang mudah menyerap dan melepaskan kalor. Setiap refrigerant memiliki karakteristik yang berbeda-beda yang mempengaruhi efek refrigerasi dan koefesien prestasi yang dihasilkan. R 22 adalah salah satu refrigeran yang memiliki karakteristik yang baik pada mesin pendingin. Software Genetron properties adalah sebuah software simulasi yang dapat menghitung aliran fluida atau refrigerant pada mesin pendingin. Genetron properties melakukan simulasi termodinamika untuk siklus kompresi uap dan memberikan hasil dalam bentuk tabulasi dan pada diagram Mollier diagram (h-s diagram). Pengujian prestasi mesin pendingin yang menggunakan  R-22 dilakukan secara aktual dan simulasi dengan menggunakan software genetron properties. Hasil pengujian dan perhitungan menunjukkan bahwa : Kerja kompresor, COP dan performance factor  pada mesin pendingin kompresi uap ketika high speed  adalah 0,528 kW,  8,42 dan 0,1187;  saat low speed adalah 0,528 kW; 8,52 dan 0,117.  COP dari   hasil pengujian dengan software genetron properties ketika high speed 2,193 saat low speed 1,415 hal ini dikarenakan mesin pendingin kompresi uap dalam keadaan tidak optimalKata Kunci : Mesin Pendingin, Kompresi Uap, COP AbstractAir conditioning system that regulates temperature and humidity in the room, in operation requires refrigerants that are easy to absorb and release heat. Each refrigerant has different characteristics that affect the effects of refrigeration and the performance coefficients produced. R 22 is one of the refrigerants that has good characteristics on cooling system. Genetron properties is a simulation software that can calculate fluid flow or refrigerant on a cooling sistem. Genetron properties perform thermodynamic simulations for vapor compression cycles and provide results in tabulation and Mollier diagram diagrams (h-s diagrams). Testing the performance of cooling system using R-22 is done in actual and simulated using genetron properties software. The test results and calculations show tha the work of compressor, COP and performance factors on vapor compression cooling system when high speed is 0.528 kW, 8.42 and 0.1187; when low speed is 0.528 kW; 8.52 and 0.117. COP from the results of testing with genetron software properties when high speed 2,193 at low speed 1,415 this is because the vapor compression of cooling system is in an optimal condition Keyword: Cooling system, vapor compression, COP

The Effects of Orientation and Location on the Strength of Dorsal Rat Skin in High and Low Speed Tensile Failure Experiments

1989 ◽  
Vol 111 (2) ◽  
pp. 136-140 ◽  
Author(s):  
R. C. Haut
Keyword(s):  
Tensile Strength ◽  
High Speed ◽  
The Body ◽  
Tensile Failure ◽  
Rat Skin ◽  
Low Speed ◽  
Similar Dependence ◽  
Static Tensile ◽  
Failure Properties ◽  
Accident Statistics

The tensile strength of skin is associated, in part, with its potential for laceration from impact. The quasi-static tensile strength of skin depends on orientation. The objective of this study was to determine whether the strength of skin in high speed tensile failure experiments exhibits a similar dependence on orientation. Tensile experiments were conducted at 6000 percent/s and 30 percent/s on dorsal skin of rats aged 1–6 months. Experiments were performed on specimens cut perpendicularly and longitudinally to the spine at cranial and caudal locations. The tensile failure properties depended on location, orientation, age and strain rate. The strength was dependent on orientation to the same degree in high and low speed tests. This helps explain why accident statistics show that skin lacerates preferentially on the body.

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