Tuna robotics: A high-frequency experimental platform exploring the performance space of swimming fishes

2019 ◽  
Vol 4 (34) ◽  
pp. eaax4615 ◽  
Author(s):  
J. Zhu ◽  
C. White ◽  
D. K. Wainwright ◽  
V. Di Santo ◽  
G. V. Lauder ◽  
...  
Keyword(s):  
High Frequency ◽  
High Performance ◽  
Swimming Performance ◽  
Beat Frequency ◽  
Cost Of Transport ◽  
Low Frequencies ◽  
Atlantic Mackerel ◽  
Performance Space ◽  
Wide Range ◽  
Tail Beat

Tuna and related scombrid fishes are high-performance swimmers that often operate at high frequencies, especially during behaviors such as escaping from predators or catching prey. This contrasts with most fish-like robotic systems that typically operate at low frequencies (< 2 hertz). To explore the high-frequency fish swimming performance space, we designed and tested a new platform based on yellowfin tuna (Thunnus albacares) and Atlantic mackerel (Scomber scombrus). Body kinematics, speed, and power were measured at increasing tail beat frequencies to quantify swimming performance and to study flow fields generated by the tail. Experimental analyses of freely swimming tuna and mackerel allow comparison with the tuna-like robotic system. The Tunabot (255 millimeters long) can achieve a maximum tail beat frequency of 15 hertz, which corresponds to a swimming speed of 4.0 body lengths per second. Comparison of midline kinematics between scombrid fish and the Tunabot shows good agreement over a wide range of frequencies, with the biggest discrepancy occurring at the caudal fin, primarily due to the rigid propulsor used in the robotic model. As frequency increases, cost of transport (COT) follows a fish-like U-shaped response with a minimum at ~1.6 body lengths per second. The Tunabot has a range of ~9.1 kilometers if it swims at 0.4 meter per second or ~4.2 kilometers at 1.0 meter per second, assuming a 10–watt-hour battery pack. These results highlight the capabilities of high-frequency biological swimming and lay the foundation to explore a fish-like performance space for bio-inspired underwater vehicles.

THE EFFECT OF SOLID AND POROUS CHANNEL WALLS ON STEADY SWIMMING OF STEELHEAD TROUT ONCORHYNCHUS MYKISS

1993 ◽  
Vol 178 (1) ◽  
pp. 97-108 ◽  
Author(s):  
P. W. Webb
Keyword(s):  
Swimming Speed ◽  
Swimming Performance ◽  
Beat Frequency ◽  
Regression Coefficients ◽  
Steelhead Trout ◽  
Wall Effects ◽  
Fish Swimming ◽  
Wide Channel ◽  
Solid Walls ◽  
Tail Beat

Kinematics and steady swimming performance were recorded for steelhead trout (approximately 12.2 cm in total length) swimming in channels 4.5, 3 and 1.6 cm wide in the centre of a flume 15 cm wide. Channel walls were solid or porous. Tail-beat depth and the length of the propulsive wave were not affected by spacing of either solid or porous walls. The product of tail-beat frequency, F, and amplitude, H, was related to swimming speed, u, and to harmonic mean distance of the tail from the wall, z. For solid walls: FH = 1.01(+/−0.31)u0.67(+/−0.09)z(0.12+/−0.02) and for grid walls: FH = 0.873(+/−0.302)u0.74(+/−0.08)z0.064(+/−0.024), where +/−2 s.e. are shown for regression coefficients. Thus, rates of working were smaller for fish swimming between solid walls, but the reduction due to wall effects decreased with increasing swimming speed. Porous grid walls had less effect on kinematics, except at low swimming speeds. Spacing of solid walls did not affect maximum tail-beat frequency, but maximum tail-beat amplitude decreased with smaller wall widths. Maximum tail-beat amplitude similarly decreased with spacing between grid walls, but maximum tail-beat frequency increased. Walls also reduced maximum swimming speed. Wall effects have not been adequately taken into account in most studies of fish swimming in flumes and fish wheels.

Hipernetch: High-Performance FPGA Network Switch

2022 ◽  
Vol 15 (1) ◽  
pp. 1-31
Author(s):  
Philippos Papaphilippou ◽  
Jiuxi Meng ◽  
Nadeen Gebara ◽  
Wayne Luk
Keyword(s):  
High Frequency ◽  
High Performance ◽  
Data Centers ◽  
Round Robin ◽  
Switching Performance ◽  
Wide Range ◽  
Crossbar Switches ◽  
High Bandwidth ◽  
Network Switch ◽  
Network Switches

We present Hipernetch, a novel FPGA-based design for performing high-bandwidth network switching. FPGAs have recently become more popular in data centers due to their promising capabilities for a wide range of applications. With the recent surge in transceiver bandwidth, they could further benefit the implementation and refinement of network switches used in data centers. Hipernetch replaces the crossbar with a “combined parallel round-robin arbiter”. Unlike a crossbar, the combined parallel round-robin arbiter is easy to pipeline, and does not require centralised iterative scheduling algorithms that try to fit too many steps in a single or a few FPGA cycles. The result is a network switch implementation on FPGAs operating at a high frequency and with a low port-to-port latency. Our proposed Hipernetch architecture additionally provides a competitive switching performance approaching output-queued crossbar switches. Our implemented Hipernetch designs exhibit a throughput that exceeds 100 Gbps per port for switches of up to 16 ports, reaching an aggregate throughput of around 1.7 Tbps.

scholarly journals The influence of cerebellar lesions on the swimming performance of the trout

1992 ◽  
Vol 167 (1) ◽  
pp. 171-178
Author(s):  
B. L. Roberts ◽  
A. van Rossem ◽  
S. de Jager
Keyword(s):  
Swimming Performance ◽  
Beat Frequency ◽  
Water Tunnel ◽  
Histological Investigation ◽  
Post Mortem ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Cerebellar Lesions ◽  
All Speeds ◽  
The Relationship ◽  
Tail Beat

The influence of partial cerebellar ablation on the performance of rainbow trout, Oncorhynchus mykiss, swimming in a water tunnel was studied. Before surgery, all fish maintained a steady position in the water tunnel at all speeds tested. A linear relationship was found between the specific velocity (body length s-1) and the tail-beat frequency. After partial cerebellectomy, the fish swam well in the tunnel at low speeds, retaining the relationship between tail-beat frequency and specific velocity, but they were unable to maintain a steady position at water speeds requiring tail-beat frequencies above 3.5 s-1 and were swept backwards. Two sham-operated fish swam at all water speeds tested. Post mortem histological investigation showed that the lesions were restricted to the cerebellar corpus. We conclude that the cerebellum plays no role in the generation of motor programmes but may be essential for their selection and implementation.

On the Function of the White Muscles in Teleosts at Intermediate Swimming Speeds

1973 ◽  
Vol 58 (2) ◽  
pp. 509-522 ◽  
Author(s):  
RICHARD C. L. HUDSON
Keyword(s):  
Rainbow Trout ◽  
Linear Relationship ◽  
Muscle Mass ◽  
Swimming Performance ◽  
Beat Frequency ◽  
Salmo Gairdneri ◽  
Electrical Activities ◽  
Tail Beat ◽  
Increased Activity

1. The swimming performance of rainbow trout, Salmo gairdneri, and the electrical activities, recorded extracellularly, of its red and mosaic muscles have been studied at different swimming speeds. 2. A linear relationship was found between the specific velocity (body lengths/sec) and the frequency of tail beating at frequencies up to 5/sec. 3. The red muscles are active at all swimming speeds at which the fish swim by tail oscillations. Discharges from this muscle decrease in duration with frequency up to 3.5-5.0 beats/sec and then increase while the interburst interval decreases linearly with tail-beat frequency. 4. Mosaic muscle becomes active at 3.05-3.60 tail beats/sec and increases slightly with increasing frequency of tail oscillations. Greatly increased activity was recorded in response to struggling and rapid accelerations. 5. The white (mosaic) muscle mass of teleosts is concluded to be involved at intermediate swimming speeds and to be active at the higher range of cruising speeds.

Going against the flow: an examination of the propulsive movements made by young brook trout in streams

1998 ◽  
Vol 55 (4) ◽  
pp. 853-860 ◽  
Author(s):  
Robert L McLaughlin ◽  
David LG Noakes
Keyword(s):  
Brook Trout ◽  
Swimming Performance ◽  
Beat Frequency ◽  
Fork Length ◽  
Spatial Location ◽  
Laboratory Studies ◽  
Pectoral Fins ◽  
Tail Beat ◽  
Temporal And Spatial Heterogeneity ◽  
A Current

We examined the propulsive movements and behaviour of young-of-the-year (YOY) brook trout (Salvelinus fontinalis) swimming in their natal streams. Our findings demonstrated that swimming performance was influenced by temporal and spatial heterogeneity in water flow. Pectoral fins were used commonly, even by individuals swimming in fast flowing water. There also was spatial variation in the speed attained for a given tail-beat frequency and amplitude. After controlling statistically for variation in spatial location, fork length, and tail-beat amplitude, the swimming speeds brook trout attained for a given tail-beat frequency were lower than values expected from laboratory studies of steady swimming but higher than values expected from laboratory studies of unsteady swimming in standing water. Trout holding station made short-term adjustments in tail-beat frequency also suggesting a degree of unsteady swimming. A field experiment demonstrated that introduction of a current-velocity refuge reduced swimming costs by 10%, on average, without affecting the frequency of foraging attempts made.

scholarly journals Optimum Curvature Characteristics of Body/Caudal Fin Locomotion

2021 ◽  
Vol 9 (5) ◽  
pp. 537
Author(s):  
Yanwen Liu ◽  
Hongzhou Jiang
Keyword(s):  
High Speed ◽  
High Efficiency ◽  
Swimming Performance ◽  
Beat Frequency ◽  
Reaction Force ◽  
Body Motion ◽  
Entire Body ◽  
Cost Of Transport ◽  
Caudal Fin ◽  
Swimming Mode

Fish propelled by body and/or caudal fin (BCF) locomotion can achieve high-efficiency and high-speed swimming performance, by changing their body motion to interact with external fluids. This flexural body motion can be prescribed through its curvature profile. This work indicates that when the fish swims with high efficiency, the curvature amplitude reaches a maximum at the caudal peduncle. In the case of high-speed swimming, the curvature amplitude shows three maxima on the entire body length. It is also demonstrated that, when the Reynolds number is in the range of 104–106, the swimming speed, stride length, and Cost of Transport (COT) are all positively correlated with the tail-beat frequency. A sensitivity analysis of curvature amplitude explains which locations change the most when the fish switches from the high-efficiency swimming mode to the high-speed swimming mode. The comparison among three kinds of BCF fish shows that the optimal swimming performance of thunniform fish is almost the same as that of carangiform fish, while it is better not to neglect the reaction force acting on an anguilliform fish. This study provides a reference for curvature control of bionic fish in a future time.

Swimming performance and behaviour of young-of-the-year shortnose sturgeon (Acipenser brevirostrum) under fixed and increased velocity swimming tests

2012 ◽  
Vol 90 (3) ◽  
pp. 345-351 ◽  
Author(s):  
D. Deslauriers ◽  
J.D. Kieffer
Keyword(s):  
Swimming Performance ◽  
Beat Frequency ◽  
Significant Negative Correlation ◽  
Shortnose Sturgeon ◽  
Fish Swimming ◽  
Acipenser Brevirostrum ◽  
Burst Swimming ◽  
Young Of The Year ◽  
All Speeds ◽  
Tail Beat

Swimming performance and behaviour in fish has been shown to vary depending on the investigation method. In this study, an endurance swimming curve was generated for young-of-the-year shortnose sturgeon (Acipenser brevirostrum LeSueur, 1818) (~7 cm total length, ~2 g) and compared with values determined in a separate incremental swimming (critical swimming, Ucrit) test. Using video, tail-beat frequency (TBF) was quantified and compared for fish swimming under both swimming tests. From the endurance-curve analysis, it was found that sturgeon did not display a statistically significant burst swimming phase. Maximum sustainable swimming speed (calculated to be 18.00 cm·s–1) from the endurance curve occurred at ~80% of Ucrit (22.30 cm·s–1). TBF was similar at all speeds for both swimming tests, except at speeds approaching Ucrit, where fish displayed TBFs of 4.29 Hz for the endurance protocol and 2.26 Hz for the Ucrit protocol. TBF was more variable between individuals swimming at the same speed within the Ucrit compared with the endurance protocol. Finally, a significant negative correlation was found between TBF and Ucrit in individual fish, suggesting that station-holding may be an important energy saving strategy during swimming in this size class of sturgeon.

scholarly journals On the variation with frequency of the conductivity and dielectric constant of dielectrics for high-frequency oscilla­tions

1920 ◽  
Vol 96 (679) ◽  
pp. 363-382 ◽  
Keyword(s):  
Dielectric Constant ◽  
Energy Loss ◽  
High Frequency ◽  
Sine Wave ◽  
Wave Form ◽  
Low Frequencies ◽  
Wide Range ◽  
Energy Dissipated ◽  
Amount Of Knowledge ◽  
Dielectric Conductivity

Although we have a certain amount of knowledge regarding the variation of the conductivity of dielectrics with frequency for comparatively low frequencies, within the telephonic range, say, up to 5000 per second, where the conductivity is in general a linear function of the frequency, it cannot be said that any information exists at present as to what happens when we extend the range of frequencies up to those employed in radiotelegraphic work. That energy is dissipated in condensers used in oscillation circuits has been known since 1861, when W. Siemens pointed out that the glass of a Leyden jar became heated on charge and discharge. Threlfall, extending the early experiments of Arno, working with a rotating electrostatic field, found that under these conditions there was no hysteresis loss at 10 7 ∼ per second in the dielectrics he employed: ebonite, glass, and sulphur. At somewhat lower frequencies of the order of a million a second, several observers have made measurements of the energy dissipated, and find that condensers have an appreciable decrement. Reference may be made to the following: W. Hahnemann and L. Adelmann, G. Dupreux, J. J. Stockley, M. Wien, J. A. Fleming and G. B. Dyke, L. W. Austin, E. F. W. Alexanderson. Most of the measurements were made at working voltages, so it is impossible to say how much of the energy loss is due to brush discharges and how much to a true dielectric conductivity. Moreover, the measurements have generally been confined to some particular frequency. The object of the experiments to be described below was to measure the conductivity of the dielectric over a wide range of frequency, employing continuous oscilla­tions of sine wave form, and of low voltages.

scholarly journals Fishes regulate tail-beat kinematics to minimize speed-specific cost of transport

2021 ◽  
Vol 288 (1964) ◽  
Author(s):  
Gen Li ◽  
Hao Liu ◽  
Ulrike K. Müller ◽  
Cees J. Voesenek ◽  
Johan L. van Leeuwen
Keyword(s):  
Beat Frequency ◽  
Aquatic Organisms ◽  
Future Research ◽  
Cost Of Transport ◽  
Wave Kinematics ◽  
Larval Fishes ◽  
Dynamics Models ◽  
Undulatory Swimming ◽  
Energetic Expenditure ◽  
Tail Beat

Energetic expenditure is an important factor in animal locomotion. Here we test the hypothesis that fishes control tail-beat kinematics to optimize energetic expenditure during undulatory swimming. We focus on two energetic indices used in swimming hydrodynamics, cost of transport and Froude efficiency. To rule out one index in favour of another, we use computational-fluid dynamics models to compare experimentally observed fish kinematics with predicted performance landscapes and identify energy-optimized kinematics for a carangiform swimmer, an anguilliform swimmer and larval fishes. By locating the areas in the predicted performance landscapes that are occupied by actual fishes, we found that fishes use combinations of tail-beat frequency and amplitude that minimize cost of transport. This energy-optimizing strategy also explains why fishes increase frequency rather than amplitude to swim faster, and why fishes swim within a narrow range of Strouhal numbers. By quantifying how undulatory-wave kinematics affect thrust, drag, and power, we explain why amplitude and frequency are not equivalent in speed control, and why Froude efficiency is not a reliable energetic indicator. These insights may inspire future research in aquatic organisms and bioinspired robotics using undulatory propulsion.

Atomic Vapour Deposition (AVD™) Process for High Performance HfO22 Dielectric Layers

2004 ◽  
Vol 811 ◽  
Author(s):  
V. Cosnier ◽  
K. Dabertrand ◽  
S. Blonkowski ◽  
S. Lhostis ◽  
S. Zoll ◽  
...  
Keyword(s):  
High Performance ◽  
Vapour Deposition ◽  
Gate Dielectric ◽  
Dielectric Materials ◽  
Low Frequencies ◽  
High K ◽  
Wide Range ◽  
Structural And Electrical Properties ◽  
Huge Impact ◽  
Higher Temperature

ABSTRACTHf-family compounds have been widely studied as high k gate dielectric materials, they can be elaborated in a wide range of deposition techniques but ALD and MOCVD are the most advanced. In this contribution, the deposition of pure HfO2 is performed by Atomic Vapour Deposition, which is a sort of pulsed-mode MOCVD. The precursor, diluted into a solvent, is pulsed through specific injectors (TriJet®), micro-droplets are vaporised and distributed to the substrate through a showerhead. ATR-FTIR and Hg-probe measurements have been extensively used to evaluate the materials. The advantage of this specific MOCVD system is that it allows working within a wide range of liquid injection frequencies. Thus, we have been able to show that the frequency of injection has a huge impact on the structural and electrical properties of the material. It has been evidence that working at low frequencies is crucial in order to get good electrical behaviour. Higher temperature deposition shows also a clear benefit. An EOT of 1.15 nm with 6.10−2 A/cm2 at |Vfb| + 1 V, that is to say about 3 orders of magnitude below what is obtained with SiO2 has been obtained on capacitors with TiN gate. This is a very good achievement fore pure HfO2 deposited by MOCVD.This work has been made in the frame of MEDEA + T207 European project with the help of Air Liquide and Epichem.

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