Journal articles: 'High-speed Videography'

1

Green, Alan, and Paul Cooper. "EXPERIMENTAL CHARACTERIZATION OF WILDFIRE SPRINKLER SPRAYS USING HIGH-SPEED VIDEOGRAPHY." Atomization and Sprays 29, no. 5 (2019): 381–402. http://dx.doi.org/10.1615/atomizspr.2019031403.

Full text

APA, Harvard, Vancouver, ISO, and other styles

2

Bengochea, Leticia Vazquez, Yasa Sampurno, Calliandra Stuffle, Ruochen Han, Chris Rogers, and Ara Philipossian. "Visualizing Slurry Flow in Chemical Mechanical Planarization via High-Speed Videography." ECS Journal of Solid State Science and Technology 7, no. 3 (2018): P118—P124. http://dx.doi.org/10.1149/2.0191803jss.

Full text

APA, Harvard, Vancouver, ISO, and other styles

3

Hashimoto, Kazuki, Hikaru Mizuno, Keiichi Nakagawa, Ryoichi Horisaki, Atsushi Iwasaki, Fumihiko Kannari, Ichiro Sakuma, and Keisuke Goda. "High-speed multispectral videography with a periscope array in a spectral shaper." Optics Letters 39, no. 24 (December 12, 2014): 6942. http://dx.doi.org/10.1364/ol.39.006942.

Full text

APA, Harvard, Vancouver, ISO, and other styles

4

Hosaka, Keiichi, Antonin Tichy, Masaomi Ikeda, Keiichi Nakagawa, Alireza Sadr, Junji Tagami, Masahiro Takahashi, et al. "Ultra-high-speed videography of resin–dentin interface failure dynamics under tensile load." Dental Materials 35, no. 7 (July 2019): e153-e161. http://dx.doi.org/10.1016/j.dental.2019.04.006.

Full text

APA, Harvard, Vancouver, ISO, and other styles

5

Schmidt, Leander, Klaus Schricker, Jean Pierre Bergmann, and Christina Junger. "Effect of Local Gas Flow in Full Penetration Laser Beam Welding with High Welding Speeds." Applied Sciences 10, no. 5 (March 9, 2020): 1867. http://dx.doi.org/10.3390/app10051867.

Full text

Abstract:

Spatter formation is a major issue in deep penetration welding with solid-state lasers at high welding speeds above 8 m/min. In order to limit spatter formation, the use of local gas flows represents a technically feasible solution. By using the gas flow, the pressure balance inside the keyhole, and therefore the keyhole stability, is affected. Existing investigations demonstrate a reduction in spatter and pore formation for partial penetration welding up to a welding speed of 5 m/min. However, the effect of the gas flow is not yet clarified for full penetration welding at welding speeds above 8 m/min. By using a precisely adjustable shielding gas supply, the effect of a local gas flow of argon was characterized by welding stainless steel AISI304 (1.4301/X5CrNi18-10). The influence of the gas flow on the melt pool dynamics and spatter formation was recorded by means of high-speed videography and subsequently analyzed by image processing. Schlieren videography was used to visualize the forming flow flied. By the use of the gas, a change in melt pool dynamics and gas flow conditions was observed, correlating to a reduction in loss of mass up to 70%. Based on the investigations, a model of the acting effect mechanism was given.

APA, Harvard, Vancouver, ISO, and other styles

6

PARATE, Bhupesh Ambadas, Sunil CHANDEL, Himanshu SHEKHAR, and Viwek MAHTO. "Experimental and Theoretical Determination of Water-Jet Velocity for Disruptor Application Using High Speed Videography." Problems of Mechatronics Armament Aviation Safety Engineering 10, no. 2 (June 30, 2019): 23–41. http://dx.doi.org/10.5604/01.3001.0013.2114.

Full text

Abstract:

Experimental and theoretical determination of water-jet velocity using high speed videography for disruptor application is reported in this paper. Water-jet disruptor extensively uses the water as a liquid projectile. It helps to destroy improvised explosive devices (IEDs) or explosive devices (EDs) by breaking detonating cord in the system, making it non-operational. The use of such system against suspected objects is a fashion that continues to be met tremendous achievement. Such a device is also known as explosive ordnance disposal (EOD) disruptor. It is used by bomb technicians or squad to make disable and/or neutralize at a safe distance. The primary purpose of an EOD disruptor is to remotely open or provide destruction to suspected objects. To “remotely open” is to open the suspect objects, exposing their contents. “Provide destruction” means penetrating, cutting, or removing the components of the fusing system in order to make them disable. A secondary purpose of a disruptor is to create a means of access (for example, through a window or door of vehicle or into a trunk). Double and single base propellants are used in the experimental trials for assessing water-jet velocities. An attempt has been made to validate the water-jet velocity using experimentally high speed videography for the first time and making its theoretical analysis by conducting the various trials at a laboratory with different propellants. The stand-off distance between disruptor and target is 0.5 m. This kind of research work is not reported in open access till the date. This is the newness of this research work. The experimental water-jet velocity for single base propellant varies from 349.63 to 503.56 m/s and for double base propellant it varies from 515.07 to 890 m/s. The theoretical water-jet velocity for single base and double base propellant works out to be as 616.44 m/s and 692.62 m/s respectively. From this research study, it is concluded that there is good agreement between theoretical and experimental results.

APA, Harvard, Vancouver, ISO, and other styles

7

Burdge, Justin, Nathan T. Fried, and Ishmail Abdus-Saboor. "Using high-speed videography for objective and reproducible pain measurement on a mouse pain scale." STAR Protocols 2, no. 1 (March 2021): 100322. http://dx.doi.org/10.1016/j.xpro.2021.100322.

Full text

APA, Harvard, Vancouver, ISO, and other styles

8

Smith, Nicholas M., Hossein Ebrahimi, Ranajay Ghosh, and Andrew K. Dickerson. "High-speed microjets issue from bursting oil gland reservoirs of citrus fruit." Proceedings of the National Academy of Sciences 115, no. 26 (June 11, 2018): E5887—E5895. http://dx.doi.org/10.1073/pnas.1720809115.

Full text

Abstract:

The rupture of oil gland reservoirs housed near the outer surface of the citrus exocarp is a common experience to the discerning citrus consumer and bartenders the world over. These reservoirs often rupture outwardly in response to bending the peel, which compresses the soft material surrounding the reservoirs, the albedo, increasing fluid pressure in the reservoir. Ultimately, fluid pressure exceeds the failure strength of the outermost membrane, the flavedo. The ensuing high-velocity discharge of oil and exhaustive emptying of oil gland reservoirs creates a method for jetting small quantities of the aromatic oil. We compare this jetting behavior across five citrus hybrids through high-speed videography. The jetting oil undergoes an extreme acceleration to reach velocities in excess of 10 m/s. Through material characterization and finite element simulations, we rationalize the combination of tuned material properties and geometries enabling the internal reservoir pressures that produce explosive dispersal, finding the composite structure of the citrus peel is critical for microjet production.

APA, Harvard, Vancouver, ISO, and other styles

9

Zhang, Cheng-Zhong, Guang-Ming Zhang, Bang-yan Ye, and Li-dong Liang. "Three Dimensional Motion Tracking of a Point on a Bowed Violin String Using High Speed Videography." Acta Acustica united with Acustica 100, no. 3 (May 1, 2014): 574–82. http://dx.doi.org/10.3813/aaa.918736.

Full text

APA, Harvard, Vancouver, ISO, and other styles

10

Bobzin, K., M. Öte, M. A. Knoch, I. Alkhasli, and H. Heinemann. "High-Speed Video Analysis of the Process Stability in Plasma Spraying." Journal of Thermal Spray Technology 30, no. 4 (February 16, 2021): 987–1000. http://dx.doi.org/10.1007/s11666-021-01159-1.

Full text

Abstract:

AbstractIn plasma spraying, instabilities and fluctuations of the plasma jet have a significant influence on the particle in-flight temperatures and velocities, thus affecting the coating properties. This work introduces a new method to analyze the stability of plasma jets using high-speed videography. An approach is presented, which digitally examines the images to determine the size of the plasma jet core. By correlating this jet size with the acquisition time, a time-dependent signal of the plasma jet size is generated. In order to evaluate the stability of the plasma jet, this signal is analyzed by calculating its coefficient of variation cv. The method is validated by measuring the known difference in stability between a single-cathode and a cascaded multi-cathode plasma generator. For this purpose, a design of experiment, covering a variety of parameters, is conducted. To identify the cause of the plasma jet fluctuations, the frequency spectra are obtained and subsequently interpreted by means of the fast Fourier transformation. To quantify the significance of the fluctuations on the particle in-flight properties, a new single numerical parameter is introduced. This parameter is based on the fraction of the time-dependent signal of the plasma jet in the relevant frequency range.

APA, Harvard, Vancouver, ISO, and other styles

11

Medici, V., and S. N. Fry. "Embodied linearity of speed control in Drosophila melanogaster." Journal of The Royal Society Interface 9, no. 77 (August 29, 2012): 3260–67. http://dx.doi.org/10.1098/rsif.2012.0527.

Full text

Abstract:

Fruitflies regulate flight speed by adjusting their body angle. To understand how low-level posture control serves an overall linear visual speed control strategy, we visually induced free-flight acceleration responses in a wind tunnel and measured the body kinematics using high-speed videography. Subsequently, we reverse engineered the transfer function mapping body pitch angle onto flight speed. A linear model is able to reproduce the behavioural data with good accuracy. Our results show that linearity in speed control is realized already at the level of body posture-mediated speed control and is therefore embodied at the level of the complex aerodynamic mechanisms of body and wings. Together with previous results, this study reveals the existence of a linear hierarchical control strategy, which can provide relevant control principles for biomimetic implementations, such as autonomous flying micro air vehicles.

APA, Harvard, Vancouver, ISO, and other styles

12

Santoso, Fiorency, Viacheslav V. Krylov, Agnes L. Castillo, Ferry Saputra, Hong-Ming Chen, Hong-Thih Lai, and Chung-Der Hsiao. "Cardiovascular Performance Measurement in Water Fleas by Utilizing High-Speed Videography and ImageJ Software and Its Application for Pesticide Toxicity Assessment." Animals 10, no. 9 (September 5, 2020): 1587. http://dx.doi.org/10.3390/ani10091587.

Full text

Abstract:

Water fleas are a good model for ecotoxicity studies, and were proposed for this purpose by the United States Environmental Protection Agency, due to their easy culture, body transparency, and high sensitivity to chemical pollution. Cardiovascular function parameters are usually used as an indicator of toxicity evaluation. However, due to the nature of the heart and blood flow, and the speed of the heartbeat, it is difficult to perform precise heartbeat and blood flow measurements with a low level of bias. In addition, the other cardiovascular parameters, including stroke volume, cardiac output, fractional shortening, and ejection fraction, have seldom been carefully addressed in previous studies. In this paper, high-speed videography and ImageJ-based methods were adopted to analyze cardiovascular function in water fleas. The heartbeat and blood flow for three water flea species, Daphnia magna, Daphnia silimis, and Moina sp., were captured by high-speed videography and analyzed using open-source ImageJ software. We found the heartbeat is species-dependent but not size-dependent in water fleas. Among the three water fleas tested, D. magna was identified as having the most robust heartbeat and blood flow rate, and is therefore suitable for the ecotoxicity test. Moreover, by calculating the diameter of the heart, we succeeded in measuring other cardiovascular parameters. D. magna were challenged with temperature changes and a pesticide (imidacloprid) to analyze variations in its cardiovascular function. We found that the heartbeat of D. magna was temperature-dependent, since the heartbeat was increasing with temperature. A similar result was shown in the cardiac output parameter. We also observed that the heartbeat, cardiac output, and heartbeat regularity are significantly reduced when exposed to imidacloprid at a low dose of 1 ppb (parts per billion). The blood flow rate, stroke volume, ejection fraction, and fractional shortening, on the contrary, did not display significant changes. In conclusion, in this study, we report a simple, highly accurate, and cost-effective method to perform physiological and toxicological assessments in water fleas.

APA, Harvard, Vancouver, ISO, and other styles

13

Tanabe, Rie, Thao T. P. Nguyen, Takahiro Sugiura, and Yoshiro Ito. "Bubble dynamics in metal nanoparticle formation by laser ablation in liquid studied through high-speed laser stroboscopic videography." Applied Surface Science 351 (October 2015): 327–31. http://dx.doi.org/10.1016/j.apsusc.2015.05.030.

Full text

APA, Harvard, Vancouver, ISO, and other styles

14

Kohsakowski, Sebastian, Bilal Gökce, Rie Tanabe, Philipp Wagener, Anton Plech, Yoshiro Ito, and Stephan Barcikowski. "Target geometry and rigidity determines laser-induced cavitation bubble transport and nanoparticle productivity – a high-speed videography study." Physical Chemistry Chemical Physics 18, no. 24 (2016): 16585–93. http://dx.doi.org/10.1039/c6cp01232a.

Full text

Abstract:

Productivity of laser ablation in liquids we found that the productivity is enhanced for a wire tip laser ablation due to a springboard-like effect of the flexible target releasing the cavitation bubble.

APA, Harvard, Vancouver, ISO, and other styles

15

Roy, Subrata, Sushil Kumar Mandal, and Avimanyu Das. "Segregation and Process Features in a Teeter Bed Separator as Revealed by High-Speed Videography and Image Processing." Mineral Processing and Extractive Metallurgy Review 35, no. 1 (June 18, 2013): 15–22. http://dx.doi.org/10.1080/08827508.2012.700659.

Full text

APA, Harvard, Vancouver, ISO, and other styles

16

Isakov, Lange, Kilchert, and May. "In-Situ Damage Evaluation of Pure Ice under High Rate Compressive Loading." Materials 12, no. 8 (April 15, 2019): 1236. http://dx.doi.org/10.3390/ma12081236.

Full text

Abstract:

The initiation and propagation of damage in pure ice specimens under high rate compressive loading at the strain rate range of 100 s−1 to 600 s−1 was studied by means of Split Hopkinson Pressure Bar measurements with incorporated high-speed videography. The results indicate that local cracks in specimens can form and propagate before the macroscopic stress maximum is reached. The estimated crack velocity was in the range of 500 m/s to 1300 m/s, i.e., lower than, but in similar order of magnitude as the elastic wave speed within ice. This gives reason to suspect that already at this strain rate the specimen is not deforming under perfect force equilibrium when the first cracks initiate and propagate. In addition, in contrast to quasi-static experiments, in the high rate experiments the specimens showed notable residual load carrying capacity after the maximum stress. This was related to dynamic effects in fractured ice particles, which allowed the specimen to carry compressive load even in a highly damaged state.

APA, Harvard, Vancouver, ISO, and other styles

17

Warrick, Douglas R., Tyson L. Hedrick, Andrew A. Biewener, Kristen E. Crandell, and Bret W. Tobalske. "Foraging at the edge of the world: low-altitude, high-speed manoeuvering in barn swallows." Philosophical Transactions of the Royal Society B: Biological Sciences 371, no. 1704 (September 26, 2016): 20150391. http://dx.doi.org/10.1098/rstb.2015.0391.

Full text

Abstract:

While prior studies of swallow manoeuvering have focused on slow-speed flight and obstacle avoidance in still air, swallows survive by foraging at high speeds in windy environments. Recent advances in field-portable, high-speed video systems, coupled with precise anemometry, permit measures of high-speed aerial performance of birds in a natural state. We undertook the present study to test: (i) the manner in which barn swallows ( Hirundo rustica ) may exploit wind dynamics and ground effect while foraging and (ii) the relative importance of flapping versus gliding for accomplishing high-speed manoeuvers. Using multi-camera videography synchronized with wind-velocity measurements, we tracked coursing manoeuvers in pursuit of prey. Wind speed averaged 1.3–2.0 m s −1 across the atmospheric boundary layer, exhibiting a shear gradient greater than expected, with instantaneous speeds of 0.02–6.1 m s −1 . While barn swallows tended to flap throughout turns, they exhibited reduced wingbeat frequency, relying on glides and partial bounds during maximal manoeuvers. Further, the birds capitalized on the near-earth wind speed gradient to gain kinetic and potential energy during both flapping and gliding turns; providing evidence that such behaviour is not limited to large, fixed-wing soaring seabirds and that exploitation of wind gradients by small aerial insectivores may be a significant aspect of their aeroecology. This article is part of the themed issue ‘Moving in a moving medium: new perspectives on flight'.

APA, Harvard, Vancouver, ISO, and other styles

18

Martinez-del Campo, L. J., Nancy Greer, Ava Trent, Lela June Stoner, L. Wickstrom, Deborah Loch, and C. N. Kobluk. "The Use of High-Speed Videography to Generate Angle-Time and Angle-Angle Diagrams for the Study of Equine Locomotion." Veterinary and Comparative Orthopaedics and Traumatology 4, no. 04 (1991): 120–31. http://dx.doi.org/10.1055/s-0038-1633266.

Full text

Abstract:

Summary Introduction High-speed videography was used to generate angle-time and angle-angle diagrams to provide the basis for a better subjective and objective understanding of the locomotor function of the horse. Intra- and interlimb coordination patterns were analyzed in a group of ten clinically sound racing Thoroughbreds. For lateral video recording, reflective markers were glued over the axis of rotation of the fore- and hindlimb joints of the ten horses. All horses were filmed simultaneously from both sides (right and left). Means and standard deviations were calculated for the minimum, the maximum and the range of motion values for the angle excursions of each joint. Angle-time and angle-angle diagrams were highly repeatable over the eight to nine strides videotaped for each horse and showed a very characteristic shape with minor variations between individual horses. When comparing right versus left sides, horses exhibited varying levels of significant asymmetry.

APA, Harvard, Vancouver, ISO, and other styles

19

Zhan, Yakimov, Rühling, Fischbach, Nikolova, Joost, Kaddatz, et al. "High Speed Ventral Plane Videography as a Convenient Tool to Quantify Motor Deficits during Pre-Clinical Experimental Autoimmune Encephalomyelitis." Cells 8, no. 11 (November 14, 2019): 1439. http://dx.doi.org/10.3390/cells8111439.

Full text

Abstract:

Experimental autoimmune encephalomyelitis (EAE) is the most commonly used multiple sclerosis animal model. EAE mice typically develop motor deficits in a caudal-to-rostral pattern when inflammatory lesions have already developed. However, to monitor more subtle behavioral deficits during lesion development (i.e., pre-clinical phase), more sophisticated methods are needed. Here, we investigated whether high speed ventral plane videography can be applied to monitor early motor deficits during ‘pre-clinical’ EAE. For this purpose, EAE was induced in C57BL/6 mice and gait abnormalities were quantified using the DigiGait™ apparatus. Gait deficits were related to histopathological changes. 10 out of 10 control (100%), and 14 out of 18 (77.8%) pre-clinical EAE mice could be evaluated using DigiGait™. EAE severity was not influenced by DigiGait™-related mice handlings. Most gait parameters recorded from day 6 post-immunization until the end of the experiment were found to be stable in control mice. During the pre-clinical phase, when conventional EAE scorings failed to detect any functional impairment, EAE mice showed an increased Swing Time, increased %Swing Stride, decreased %Stance Stride, decreased Stance/Swing, and an increased Absolute Paw Angle. In summary, DigiGait™ is more sensitive than conventional scoring approaches to study motor deficits during the EAE pre-clinical phase.

APA, Harvard, Vancouver, ISO, and other styles

20

Dickerson, Andrew K., Zachary G. Mills, and David L. Hu. "Wet mammals shake at tuned frequencies to dry." Journal of The Royal Society Interface 9, no. 77 (August 17, 2012): 3208–18. http://dx.doi.org/10.1098/rsif.2012.0429.

Full text

Abstract:

In cold wet weather, mammals face hypothermia if they cannot dry themselves. By rapidly oscillating their bodies, through a process similar to shivering, furry mammals can dry themselves within seconds. We use high-speed videography and fur particle tracking to characterize the shakes of 33 animals (16 animals species and five dog breeds), ranging over four orders of magnitude in mass from mice to bears. We here report the power law relationship between shaking frequency f and body mass M to be f ∼ M −0.22 , which is close to our prediction of f ∼ M −0.19 based upon the balance of centrifugal and capillary forces. We also observe a novel role for loose mammalian dermal tissue: by whipping around the body, it increases the speed of drops leaving the animal and the ensuing dryness relative to tight dermal tissue.

APA, Harvard, Vancouver, ISO, and other styles

21

Anderson, P. S. L., J. LaCosse, and M. Pankow. "Point of impact: the effect of size and speed on puncture mechanics." Interface Focus 6, no. 3 (June 6, 2016): 20150111. http://dx.doi.org/10.1098/rsfs.2015.0111.

Full text

Abstract:

The use of high-speed puncture mechanics for prey capture has been documented across a wide range of organisms, including vertebrates, arthropods, molluscs and cnidarians. These examples span four phyla and seven orders of magnitude difference in size. The commonality of these puncture systems offers an opportunity to explore how organisms at different scales and with different materials, morphologies and kinematics perform the same basic function. However, there is currently no framework for combining kinematic performance with cutting mechanics in biological puncture systems. Our aim here is to establish this framework by examining the effects of size and velocity in a series of controlled ballistic puncture experiments. Arrows of identical shape but varying in mass and speed were shot into cubes of ballistic gelatine. Results from high-speed videography show that projectile velocity can alter how the target gel responds to cutting. Mixed models comparing kinematic variables and puncture patterns indicate that the kinetic energy of a projectile is a better predictor of penetration than either momentum or velocity. These results form a foundation for studying the effects of impact on biological puncture, opening the door for future work to explore the influence of morphology and material organization on high-speed cutting dynamics.

APA, Harvard, Vancouver, ISO, and other styles

22

Tran, Huy Hoang, Kiyoshi Matsumiya, Ken Masamune, Ichiro Sakuma, Takeyoshi Dohi, and Hongen Liao. "Interactive 3D Navigation System for Image-guided Surgery." International Journal of Virtual Reality 8, no. 1 (January 1, 2009): 9–16. http://dx.doi.org/10.20870/ijvr.2009.8.1.2708.

Full text

Abstract:

This paper presents a novel surgery navigation system based on a three-dimensional (3D) imaging technique, integral videography (IV). In our system, the 3D structure of the object of interest is reconstructed using surface rendering and corresponding pixel distribution methods. We developed a high-speed algorithm that renders high-quality IV images from the surface model in real time and allows interactions like rotating and scaling to be done smoothly. Using the patient-image registration method, IV images can be displayed with the correct size and relative position with respect to the surgical instruments. Experiments were carried out with various anatomical models, and the results show that our system could be useful in many clinical situations such as orthopedic surgery and neurosurgery.

APA, Harvard, Vancouver, ISO, and other styles

23

Sutherland, Kelly R., Brad J. Gemmell, Sean P. Colin, and John H. Costello. "Maneuvering Performance in the Colonial Siphonophore, Nanomia bijuga." Biomimetics 4, no. 3 (September 5, 2019): 62. http://dx.doi.org/10.3390/biomimetics4030062.

Full text

Abstract:

The colonial cnidarian, Nanomia bijuga, is highly proficient at moving in three-dimensional space through forward swimming, reverse swimming and turning. We used high speed videography, particle tracking, and particle image velocimetry (PIV) with frame rates up to 6400 s−1 to study the kinematics and fluid mechanics of N. bijuga during turning and reversing. N. bijuga achieved turns with high maneuverability (mean length–specific turning radius, R/L = 0.15 ± 0.10) and agility (mean angular velocity, ω = 104 ± 41 deg. s−1). The maximum angular velocity of N. bijuga, 215 deg. s−1, exceeded that of many vertebrates with more complex body forms and neurocircuitry. Through the combination of rapid nectophore contraction and velum modulation, N. bijuga generated high speed, narrow jets (maximum = 1063 ± 176 mm s−1; 295 nectophore lengths s−1) and thrust vectoring, which enabled high speed reverse swimming (maximum = 134 ± 28 mm s−1; 37 nectophore lengths s−1) that matched previously reported forward swimming speeds. A 1:1 ratio of forward to reverse swimming speed has not been recorded in other swimming organisms. Taken together, the colonial architecture, simple neurocircuitry, and tightly controlled pulsed jets by N. bijuga allow for a diverse repertoire of movements. Considering the further advantages of scalability and redundancy in colonies, N. bijuga is a model system for informing underwater propulsion and navigation of complex environments.

APA, Harvard, Vancouver, ISO, and other styles

24

Sustaita, Diego, Margaret A. Rubega, and Susan M. Farabaugh. "Come on baby, let's do the twist: the kinematics of killing in loggerhead shrikes." Biology Letters 14, no. 9 (September 2018): 20180321. http://dx.doi.org/10.1098/rsbl.2018.0321.

Full text

Abstract:

Shrikes use their beaks for procuring, dispatching and processing their arthropod and vertebrate prey. However, it is not clear how the raptor-like bill of this predatory songbird functions to kill vertebrate prey that may weigh more than the shrike itself. In this paper, using high-speed videography, we observed that upon seizing prey with their beaks, shrikes performed rapid (6–17 Hz; 49–71 rad s −1 ) axial head-rolling movements. These movements accelerated the bodies of their prey about their own necks at g -forces of approximately 6 g , and may be sufficient to cause pathological damage to the cervical vertebrae and spinal cord. Thus, when tackling relatively large vertebrates, shrikes appear to use inertia of their prey's own body against them.

APA, Harvard, Vancouver, ISO, and other styles

25

Wood, Hannah M. "Morphology and performance of the ‘trap-jaw’ cheliceral strikes in spiders (Araneae, Mecysmaucheniidae)." Journal of Experimental Biology 223, no. 14 (June 19, 2020): jeb219899. http://dx.doi.org/10.1242/jeb.219899.

Full text

Abstract:

ABSTRACTMecysmaucheniidae spiders have evolved ultra-fast cheliceral strikes 4 times independently. The mechanism for producing these high-speed strikes is likely due to a latch/spring system that allows for stored energy to be rapidly released. This study examined two different sister lineages: Zearchaea has ultra-fast cheliceral strikes and Aotearoa, based on external morphology of the clypeus, is hypothesized to have slower strikes. Using high-speed videography, I first gathered kinematic data on each taxon. Then, using histology and data from micro-computed tomography scanning, I examined internal cheliceral muscle morphology to test whether shifts in muscle anatomy correspond to performance differences in cheliceral strike. Results from high-speed video analysis revealed that Zearchaea achieves peak angular velocities of 25.0×103±4.8×103 rad s−1 (mean±s.d.) in durations of 0.0843±0.017 ms. The fastest recorded strike had a peak angular and linear velocity of 30.8×103 rad s−1 and 18.2 m s−1, respectively. The slower striking sister species, Aotearoa magna, was three orders of magnitude slower in velocity and longer in duration. Histology revealed sarcomere length differences, with some muscles optimized for force, and other muscles for speed. 3D printed models revealed structural differences that explain how the chelicerae hinge open and close. Combining all of this evidence, I put forth a hypothesis for the ultra-fast trap-jaw mechanism. This research documents the morphological shifts that accompany ultra-fast movements that result in increased rotation in joints and increased muscle specialization.

APA, Harvard, Vancouver, ISO, and other styles

26

Oliveira, Saulo, Afonso Bione, Lúcia Oliveira, Adalberto da Costa, Fernando de Sá Pereira Guimarães, and Manoel da Cunha Costa. "The Compact Wheelchair Roller Dynamometer." Sports Medicine International Open 1, no. 04 (July 2017): E119—E127. http://dx.doi.org/10.1055/s-0043-111404.

Full text

Abstract:

AbstractThe equipment for evaluating the propulsion of a wheelchair is very complex and expensive. To validate a new dynamometer prototype for assessing the propulsion capacity of wheelchairs, 21 healthy subjects (age: 20.9±2.4 yr; weight: 68.9±7.9 kg; height: 174.0±7.1 cm; BMI: 22.7±2.5 kg·m−2) who do not normally require wheelchairs performed a sprint protocol for 20 s after a 1-min warm-up. The power and rotation data acquired by the prototype (both right and left sides) were compared with those of a reference system via high-speed videography (240 fps). The results showed high levels of accordance (95% CI), excellent values for the intraclass correlation coefficient (ICC: .99; P<0.00), no significant differences in the rotation (P=0.91) and power (P=0.94) between the methods. The proposed equipment met the validation criteria and thus can be applied as a new tool for assessing wheelchair propulsion.

APA, Harvard, Vancouver, ISO, and other styles

27

Willmott, A. P., and C. P. Ellington. "The mechanics of flight in the hawkmoth Manduca sexta. I. Kinematics of hovering and forward flight." Journal of Experimental Biology 200, no. 21 (November 1, 1997): 2705–22. http://dx.doi.org/10.1242/jeb.200.21.2705.

Full text

Abstract:

High-speed videography was used to record sequences of individual hawkmoths in free flight over a range of speeds from hovering to 5 ms-1. At each speed, three successive wingbeats were subjected to a detailed analysis of the body and wingtip kinematics and of the associated time course of wing rotation. Results are presented for one male and two female moths. The clearest kinematic trends accompanying increases in forward speed were an increase in stroke plane angle and a decrease in body angle. The latter may have resulted from a slight dorsal shift in the area swept by the wings as the supination position became less ventral with increasing speed. These trends were most pronounced between hovering and 3 ms-1, and the changes were gradual; there was no distinct gait change of the kind observed in some vertebrate fliers. The wing rotated as two functional sections: the hindwing and the portion of the forewing with which it is in contact, and the distal half of the forewing. The latter displayed greater fluctuation in the angle of rotation, especially at the lower speeds. As forward speed increased, the discrepancy between the rotation angles of the two halfstrokes, and of the two wing sections, became smaller. The downstroke wing torsion was set early in the halfstroke and then held constant during the translational phase.

APA, Harvard, Vancouver, ISO, and other styles

28

Lou, Li Yan, Huan Li, Xu You Wang, Wei Wang, and Ying Gao. "Effect of Laser Beam on Double Wire Pulsed MIG Welding Process." Applied Mechanics and Materials 130-134 (October 2011): 4169–73. http://dx.doi.org/10.4028/www.scientific.net/amm.130-134.4169.

Full text

Abstract:

Based on the coupling of laser beam and double arcs, a novel process was investigated. This research set up the laser-double wire pulsed MIG hybrid welding system. Meanwhile the current and voltage sensors were used to detect welding current and arc voltage wave-form and high-speed videography system was used to observe the metal transfer process and arc behavior. The three signals were acquired synchronously. The results showed that the synergic action of the three different heat sources leads to a change in metal transfer mode. It was revealed that the metal transfer mode was two droplets per pulse in laser-double wire hybrid welding process while one droplet per pulse in double wire welding process with the same certain experiment parameters. And we also discovered that the arcs were attracted strongly by the laser beam.

APA, Harvard, Vancouver, ISO, and other styles

29

Ushakov, Sergey V., Jonas Niessen, Dante G. Quirinale, Robert Prieler, Alexandra Navrotsky, and Rainer Telle. "Measurements of Density of Liquid Oxides with an Aero-Acoustic Levitator." Materials 14, no. 4 (February 9, 2021): 822. http://dx.doi.org/10.3390/ma14040822.

Full text

Abstract:

Densities of liquid oxide melts with melting temperatures above 2000 °C are required to establish mixing models in the liquid state for thermodynamic modeling and advanced additive manufacturing and laser welding of ceramics. Accurate measurements of molten rare earth oxide density were recently reported from experiments with an electrostatic levitator on board the International Space Station. In this work, we present an approach to terrestrial measurements of density and thermal expansion of liquid oxides from high-speed videography using an aero-acoustic levitator with laser heating and machine vision algorithms. The following density values for liquid oxides at melting temperature were obtained: Y2O3 4.6 ± 0.15; Yb2O3 8.4 ± 0.2; Zr0.9Y0.1O1.95 4.7 ± 0.2; Zr0.95Y0.05O1.975 4.9 ± 0.2; HfO2 8.2 ± 0.3 g/cm3. The accuracy of density and thermal expansion measurements can be improved by employing backlight illumination, spectropyrometry and a multi-emitter acoustic levitator.

APA, Harvard, Vancouver, ISO, and other styles

30

Jiten, Shah, Joshi Gaurang, Parida Purnima, and Arkatkar Shriniwas. "Impact of Train Schedule on Pedestrian Movement on Stairway at Suburban Rail Transit Station in Mumbai, India." Advances in Civil Engineering 2015 (2015): 1–9. http://dx.doi.org/10.1155/2015/297807.

Full text

Abstract:

Pedestrian flow takes place in confined environment on stairways under the influence of composition, direction of movement, and schedule of trains. During peak-period, alighting and boarding rate is quite high resulting in very high pedestrian movement from one platform to the other to catch the next train at interchange stations. The transfer of passengers from railway platforms through common undivided stairways becomes difficult, uncomfortable, and unsafe at times when pedestrian flow reaches the capacity level. Understanding of criteria defining quality of flow that affect the effectiveness of facilities like stairways in handling the pedestrian traffic is vital for planning and designing of such facilities to ensure the desired level of service as well as safety in case of emergency. The present paper is based on the study of pedestrian movement on stairways at busy suburban rail transit interchange station at Dadar in Mumbai, India. Pedestrian movements are captured through videography at two stairways and the effect of bidirectional movement on average walking speed is analyzed. The ascending flow in small proportion is found to be more influential in causing speed reduction on undivided stairways. The outcome of the study is useful for capacity and level of service analysis while planning and designing the transit station stairways.

APA, Harvard, Vancouver, ISO, and other styles

31

FUCHIHATA, Manabu, Tamio IDA, and Yukio MIZUTANI. "Observation of Microexplosions in Spray Flames of Light Oil-Water Emulsions (2nd Report, Influence of Temporal and Spatial Resolution in High Speed Videography)." Transactions of the Japan Society of Mechanical Engineers Series B 69, no. 682 (2003): 1503–8. http://dx.doi.org/10.1299/kikaib.69.1503.

Full text

APA, Harvard, Vancouver, ISO, and other styles

32

Merlino, Robert L. "25 years of dust acoustic waves." Journal of Plasma Physics 80, no. 6 (June 25, 2014): 773–86. http://dx.doi.org/10.1017/s0022377814000312.

Full text

Abstract:

The dust acoustic wave (DAW) was first discussed by P. K. Shukla in May of 1989 at the First Capri Workshop on Dusty Plasmas. In the past 25 years, the subsequent publication of the linear and nonlinear properties of the DAW (Rao, N. N., Shukla, P. K. and Yu, M. Y. 1990 Planet. Space Sci.38, 543) has generated and sustained a large body of theoretical and experimental research that has clarified the physics of collective effects in dusty plasmas. A unique feature of the DAW is that it can be observed (literally) using laser illumination and high-speed videography, revealing details of wave-particle interactions at an unprecedented single particle level. This paper attempts to review some of the contributions and extensions of dust acoustic wave physics, as well as identify recent findings that illustrate the potential importance of this dust wave in the agglomeration of dust particles.

APA, Harvard, Vancouver, ISO, and other styles

33

Ritter, R. "LATERAL BENDING DURING LIZARD LOCOMOTION." Journal of Experimental Biology 173, no. 1 (December 1, 1992): 1–10. http://dx.doi.org/10.1242/jeb.173.1.1.

Full text

Abstract:

Lateral bending of the trunk during terrestrial, quadrupedal locomotion was analyzed in four species of lizards, using high-speed videography and computerized motion analysis. The focus of the analysis was whether lizards produce a standing or a traveling wave of bending in the trunk during locomotion. Lizards with well-developed limbs (Cnemidophorus tigris and Dipsosaurus dorsalis) exhibit a standing wave of lateral bending at low speeds, which is replaced by a traveling wave of bending as velocity increases. Lizards with diminutive limbs (Gerrhonotus kingii and Eumeces multivirgatus) exhibit a traveling wave of lateral bending, even at the lowest speeds recorded. These results are not consistent with the ideas that lizards produce a standing wave of lateral bending during locomotion or that amniote vertebrates have lost the ability to produce a traveling wave of lateral flexion due to a change in the central pattern generator that controls locomotion.

APA, Harvard, Vancouver, ISO, and other styles

34

Walker, V. A., S. J. Dyson, C. A. Tranquille, J. B. Tacey, and R. C. Murray. "Limb and thoracolumbosacral kinematics over an upright and parallel spread fence." Comparative Exercise Physiology 15, no. 1 (February 21, 2019): 55–67. http://dx.doi.org/10.3920/cep180040.

Full text

Abstract:

Jumping mechanics have been investigated at take-off, flight and landing, mainly in reference to the limbs with limited evaluation of the thoracolumbosacral region. The objectives of this study were to investigate head, neck, thoracolumbosacral and limb angles in a group of experienced showjumping horses (competing at 1.20-1.60 m) over an upright and parallel spread fence. Ten horses in active showjumping training were recruited (mean 8 years old). High-speed videography (240 Hz) was used to determine thoracolumbosacral kinematic variables of the approach and take-off. No significant differences between the upright and parallel spread fences were observed for any of the variables measured. Individual horse review showed that neck-trunk, thoracolumbar, lumbosacral, coxofemoral angles, take-off distance and speed patterns at take-off were consistent among horses and also repeatable between fence types. Head-neck, stifle and tarsal angles had great variability among horses. The main limitation of this study was that only 2D motion analysis was carried out. In conclusion, analysis of individual horse patterns showed that head, neck, back and limb angles were repeatable over submaximal upright and spread fences in ten horses. Some angles were consistent among horses, but others had individual horse variation.

APA, Harvard, Vancouver, ISO, and other styles

35

Young, Bruce A., and Krista Zahn. "Venom flow in rattlesnakes: mechanics and metering." Journal of Experimental Biology 204, no. 24 (December 15, 2001): 4345–51. http://dx.doi.org/10.1242/jeb.204.24.4345.

Full text

Abstract:

SUMMARY The functional morphology of venom injection in Crotalus atrox was explored using high-speed digital videography combined with direct recording of venom flow using perivascular flow probes. Although venom flow was variable, in most strikes the onset of venom flow was coincidental with fang penetration, and retrograde flow (venom suction) was observed prior to fang withdrawal. The duration of venom flow was consistently less than the duration of fang penetration. The occurrence of retrograde flow, ‘dry bites’ (which accounted for 35 % of the strikes) and unilateral strikes all support a hypothesis for venom pooling in the distal portion of the venom-delivery system. No significant difference in temporal or volumetric aspects of venom flow were found between defensive strikes directed at small and large rodents. With the species and size of target held constant, the duration of venom flow, maximum venom flow rate and total venom volume were all significantly lower in predatory than in defensive strikes.

APA, Harvard, Vancouver, ISO, and other styles

36

Meresman, Yonatan, and Gal Ribak. "Elastic wing deformations mitigate flapping asymmetry during manoeuvres in rose chafers (Protaetia cuprea)." Journal of Experimental Biology 223, no. 24 (November 9, 2020): jeb225599. http://dx.doi.org/10.1242/jeb.225599.

Full text

Abstract:

ABSTRACTTo manoeuvre in air, flying animals produce asymmetric flapping between contralateral wings. Unlike the adjustable vertebrate wings, insect wings lack intrinsic musculature, preventing active control over wing shape during flight. However, the wings elastically deform as a result of aerodynamic and inertial forces generated by the flapping motions. How these elastic deformations vary with flapping kinematics and flight performance in free-flying insects is poorly understood. Using high-speed videography, we measured how contralateral wings elastically deform during free-flight manoeuvring in rose chafer beetles (Protaetia cuprea). We found that asymmetric flapping during aerial turns was associated with contralateral differences in chord-wise wing deformations. The highest instantaneous difference in deformation occurred during stroke reversals, resulting from differences in wing rotation timing. Elastic deformation asymmetry was also evident during mid-strokes, where wing compliance increased the angle of attack of both wings, but reduced the asymmetry in the angle of attack between contralateral wings. A biomechanical model revealed that wing compliance can increase the torques generated by each wing, providing higher potential for manoeuvrability, while concomitantly contributing to flight stability by attenuating steering asymmetry. Such stability may be adaptive for insects such as flower chafers that need to perform delicate low-speed landing manoeuvres among vegetation.

APA, Harvard, Vancouver, ISO, and other styles

37

Seeley, Matthew K., Iain Hunter, Thomas Bateman, Adam Roggia, Brad J. Larson, and David O. Draper. "A Kinematic Comparison of Spring-Loaded and Traditional Crutches." Journal of Sport Rehabilitation 20, no. 2 (May 2011): 198–206. http://dx.doi.org/10.1123/jsr.20.2.198.

Full text

Abstract:

Context:A novel spring-loaded-crutch design may provide patients additional forward velocity, relative to traditional axillary crutches; however, this idea has not yet been evaluated.Objective:To quantify elastic potential energy stored by spring-loaded crutches during crutch–ground contact and determine whether this energy increases forward velocity for patients during crutch ambulation. Because elastic potential energy is likely stored by the spring-loaded crutch during ambulation, the authors hypothesized that subjects would exhibit greater peak instantaneous forward velocity during crutch–ground contact and increased preferred ambulation speed during spring-loaded-crutch ambulation, relative to traditional-crutch ambulation.Design:Within-subject.Setting:Biomechanics laboratory.Participants:10 healthy men and 10 healthy women.Interventions:The independent variable was crutch type: Subjects used spring-loaded and traditional axillary crutches to ambulate at standardized and preferred speeds.Main Outcome Measures:The primary dependent variables were peak instantaneous forward velocity and preferred ambulation speed; these variables were quantified using high-speed videography and an optoelectronic timing device, respectively. Between-crutches differences for the dependent variables were evaluated using paired t tests (α = .05). Elastic potential energy stored by the spring-loaded crutches during crutch–ground contact was also quantified via videography.Results:Peak forward velocity during crutch–ground contact was 5% greater (P < .001) for spring-loaded-crutch ambulation than for traditional-crutch ambulation. Preferred ambulation speed, however, did not significantly differ (P = .538) between crutch types. The spring-loaded crutches stored an average of 2.50 ± 1.96 J of elastic potential energy during crutch–ground contact.Conclusions:The spring-loaded crutches appear to have provided subjects with additional peak instantaneous forward velocity. This increased velocity, however, was relatively small and did not increase preferred ambulation speed.

APA, Harvard, Vancouver, ISO, and other styles

38

Uchizono, Nolan M., Adam L. Collins, Anirudh Thuppul, Peter L. Wright, Daniel Q. Eckhardt, John Ziemer, and Richard E. Wirz. "Emission Modes in Electrospray Thrusters Operating with High Conductivity Ionic Liquids." Aerospace 7, no. 10 (September 25, 2020): 141. http://dx.doi.org/10.3390/aerospace7100141.

Full text

Abstract:

Electrospray thruster life and mission performance are strongly influenced by grid impingement, the extent of which can be correlated with emission modes that occur at steady-state extraction voltages, and thruster command transients. Most notably, we experimentally observed skewed cone-jet emission during steady-state electrospray thruster operation, which leads to the definition of an additional grid impingement mechanism that we termed “tilted emission”. Long distance microscopy was used in conjunction with high speed videography to observe the emission site of an electrospray thruster operating with an ionic liquid propellant (EMI-Im). During steady-state thruster operation, no unsteady electrohydrodynamic emission modes were observed, though the conical meniscus exhibited steady off-axis tilt of up to 15°. Cone tilt angle was independent over a wide range of flow rates but proved strongly dependent on extraction voltage. For the geometry and propellant used, the optimal extraction voltage was near 1.6 kV. A second experiment characterized transient emission behavior by observing startup and shutdown of the thruster via flow or voltage. Three of the four possible startup and shutdown procedures transition to quiescence within ∼475 μs, with no observed unsteady modes. However, during voltage-induced thruster startup, unsteady electrohydrodynamic modes were observed.

APA, Harvard, Vancouver, ISO, and other styles

39

Phonekeo, Sulisay, Nathan Mlot, Daria Monaenkova, David L. Hu, and Craig Tovey. "Fire ants perpetually rebuild sinking towers." Royal Society Open Science 4, no. 7 (July 2017): 170475. http://dx.doi.org/10.1098/rsos.170475.

Full text

Abstract:

In the aftermath of a flood, fire ants, Solenopsis invicta , cluster into temporary encampments. The encampments can contain hundreds of thousands of ants and reach over 30 ants high. How do ants build such tall structures without being crushed? In this combined experimental and theoretical study, we investigate the shape and rate of construction of ant towers around a central support. The towers are bell shaped, consistent with towers of constant strength such as the Eiffel tower, where each element bears an equal load. However, unlike the Eiffel tower, the ant tower is built through a process of trial and error, whereby failed portions avalanche until the final shape emerges. High-speed and novel X-ray videography reveal that the tower constantly sinks and is rebuilt, reminiscent of large multicellular systems such as human skin. We combine the behavioural rules that produce rafts on water with measurements of adhesion and attachment strength to model the rate of growth of the tower. The model correctly predicts that the growth rate decreases as the support diameter increases. This work may inspire the design of synthetic swarms capable of building in vertical layers.

APA, Harvard, Vancouver, ISO, and other styles

40

China, Victor, Liraz Levy, Alex Liberzon, Tal Elmaliach, and Roi Holzman. "Hydrodynamic regime determines the feeding success of larval fish through the modulation of strike kinematics." Proceedings of the Royal Society B: Biological Sciences 284, no. 1853 (April 26, 2017): 20170235. http://dx.doi.org/10.1098/rspb.2017.0235.

Full text

Abstract:

Larval fishes experience extreme mortality rates, with 99% of a cohort perishing within days after starting to actively feed. While recent evidence suggests that hydrodynamic factors contribute to constraining larval feeding during early ontogeny, feeding is a complex process that involves numerous interacting behavioural and biomechanical components. How these components change throughout ontogeny and how they contribute to feeding remain unclear. Using 339 observations of larval feeding attempts, we quantified the effects of morphological and behavioural traits on feeding success of Sparus aurata larvae during early ontogeny. Feeding success was determined using high-speed videography, under both natural and increased water viscosity treatments. Successful strikes were characterized by Reynolds numbers that were an order of magnitude higher than those of failed strikes. The pattern of increasing strike success with increasing age was driven by the ontogeny of traits that facilitate the transition to higher Reynolds numbers. Hence, the physical growth of a larva plays an important role in its transition to a hydrodynamic regime of higher Reynolds numbers, in which suction feeding is more effective.

APA, Harvard, Vancouver, ISO, and other styles

41

Kaur, Manjit, Sahil Verma, and Kavita. "Flying Ad-Hoc Network (FANET): Challenges and Routing Protocols." Journal of Computational and Theoretical Nanoscience 17, no. 6 (June 1, 2020): 2575–81. http://dx.doi.org/10.1166/jctn.2020.8932.

Full text

Abstract:

Flying Ad-hoc Networks (FANET) play a vital part in military (defence), environment and civilian areas, for examples surveillance, traffic monitoring, search, rescue, weather monitoring, fire fighting, agriculture, videography, photography and delivery goods or product from one place to another place etc. Flying Ad-hoc Network is mainly ad-hoc network between unmanned air vehicles. There are several difficulties in flying ad-hoc network. The primary problem is in the communication between unmanned air vehicles. UAV are also known as Unmanned Aircraft Systems (UAS). The problem of Flying Ad-hoc Network is routing of multiple unmanned air vehicles. The reason behind is high speed which required highly dynamic routing protocols. The designing of routing protocol is a complicated for various parameters such as traffic monitoring, load balancing etc. Here, flying ad-hoc networks are described along with mobility models, features and routing protocols. This paper presented various routing protocols used to resolve these types of problems in Flying Ad-hoc Networks. Finally, some open research challenges in developing efficient routing protocols in the Flying Ad-hoc Networks are highlighted.

APA, Harvard, Vancouver, ISO, and other styles

42

Hudson, Cameron M., Marta Vidal-García, Trevor G. Murray, and Richard Shine. "The accelerating anuran: evolution of locomotor performance in cane toads ( Rhinella marina , Bufonidae) at an invasion front." Proceedings of the Royal Society B: Biological Sciences 287, no. 1938 (November 11, 2020): 20201964. http://dx.doi.org/10.1098/rspb.2020.1964.

Full text

Abstract:

As is common in biological invasions, the rate at which cane toads ( Rhinella marina ) have spread across tropical Australia has accelerated through time. Individuals at the invasion front travel further than range-core conspecifics and exhibit distinctive morphologies that may facilitate rapid dispersal. However, the links between these morphological changes and locomotor performance have not been clearly documented. We used raceway trials and high-speed videography to document locomotor traits (e.g. hop distances, heights, velocities, and angles of take-off and landing) of toads from range-core and invasion-front populations. Locomotor performance varied geographically, and this variation in performance was linked to morphological features that have evolved during the toads' Australian invasion. Geographical variation in morphology and locomotor ability was evident not only in wild-caught animals, but also in individuals that had been raised under standardized conditions in captivity. Our data thus support the hypothesis that the cane toad's invasion across Australia has generated rapid evolutionary shifts in dispersal-relevant performance traits, and that these differences in performance are linked to concurrent shifts in morphological traits.

APA, Harvard, Vancouver, ISO, and other styles

43

Larsen, Ole Næsbye, and Colleen Reichmuth. "Walruses produce intense impulse sounds by clap-induced cavitation during breeding displays." Royal Society Open Science 8, no. 6 (June 2021): 210197. http://dx.doi.org/10.1098/rsos.210197.

Full text

Abstract:

Male walruses produce some of the longest continuous reproductive displays known among mammals to convey their physical fitness to potential rivals and possibly to potential mates. Here, we document the ability of a captive walrus to produce intense, rhythmic sounds through a non-vocal pathway involving deliberate, regular collision of the fore flippers. High-speed videography linked to an acoustic onset marker revealed sound production through cavitation, with the acoustic impulse generated by each forceful clap exceeding a peak-to-peak sound level of 200 dB re. 1 µPa. This clapping display is in some ways quite similar to the knocking display more commonly associated with walruses in rut but is produced through a very different mechanism and with much higher amplitudes. While this clapping behaviour has not yet been documented in wild individuals, it has been observed among other mature male walruses living in human care. Production of intense sounds through cavitation has previously been documented only in crustaceans but may also be an effective means of sound production for some aquatic mammals.

APA, Harvard, Vancouver, ISO, and other styles

44

Meyers, J. J., and K. C. Nishikawa. "Comparative study of tongue protrusion in three iguanian lizards, Sceloporus undulatus, Pseudotrapelus sinaitus and Chamaeleo jacksonii." Journal of Experimental Biology 203, no. 18 (September 15, 2000): 2833–49. http://dx.doi.org/10.1242/jeb.203.18.2833.

Full text

Abstract:

The goal of this study was to investigate the function of the hyolingual muscles used during tongue protraction in iguanian lizards. High-speed videography and nerve-transection techniques were used to study prey capture in the iguanid Sceloporus undulatus, the agamid Pseudoptrapelus sinaitus and the chameleonid Chamaeleo jacksonii. Denervation of the mandibulohyoideus muscle slips had an effect only on P. sinaitus and C. jacksonii, in which tongue protrusion or projection distance was reduced. In C. jacksonii, denervation of the M. mandibulohyoideus completely prevented little hyoid protraction. Denervation of the M. verticalis had no effect on S. undulatus, but reduced tongue protrusion distance in P. sinaitus. Denervation of the accelerator muscle in C. jacksonii inhibited tongue projection completely. The function of the M. mandibulohyoideus and M. verticalis has become increasingly specialized in P. sinaitus and especially in C. jacksonii to allow greater tongue protrusion. The combined results of these treatments suggest that these three groups represent transitional forms, both morphologically and functionally, in the development of a projectile tongue.

APA, Harvard, Vancouver, ISO, and other styles

45

DEBAN, STEPHEN M., and KIISA C. NISHIKAWA. "The Kinematics of Prey Capture and the Mechanism of Tongue Protraction in the Green Tree Frog Hyla Cinerea." Journal of Experimental Biology 170, no. 1 (September 1, 1992): 235–56. http://dx.doi.org/10.1242/jeb.170.1.235.

Full text

Abstract:

Prey capture was studied in the green tree frog (Hyla cinerea) before and after denervation of either the m. genioglossus or m. submentalis using high-speed videography and kinematic analysis. The prey capture behavior and extent of tongue protraction of several members of the subfamilies Hylinae, Pelodryadinae and Phyllomedusinae were also studied. Results show that the m. genioglossus is necessary to produce complete tongue protraction and that the m. submentalis is necessary for mandibular bending, but not necessary for complete tongue protraction in Hyla cinerea. The tongue of Hyla cinerea resembles the weakly protrusible tongues of the archaeobatrachian frogs Ascaphus and Discoglossus more than the highly protrusible tongues of other neobatrachians, such as Rana or Bufo. A weakly protrusible tongue is present in the subfamilies Hylinae and Pelodryadinae, and a highly protrusible tongue is present in the subfamily Phyllomedusinae. These results suggest that hyline and pelodryadine hylids have retained the ancestral anuran tongue morphology and that highly protrusible tongues have evolved once within the family Hylidae, in the subfamily Phyllomedusinae.

APA, Harvard, Vancouver, ISO, and other styles

46

HU, DAVID L., and JOHN W. M. BUSH. "The hydrodynamics of water-walking arthropods." Journal of Fluid Mechanics 644 (February 10, 2010): 5–33. http://dx.doi.org/10.1017/s0022112009992205.

Full text

Abstract:

We present the results of a combined experimental and theoretical investigation of the dynamics of water-walking insects and spiders. Using high-speed videography, we describe their numerous gaits, some analogous to those of their terrestrial counterparts, others specialized for life at the interface. The critical role of the rough surface of these water walkers in both floatation and propulsion is demonstrated. Their waxy, hairy surface ensures that their legs remain in a water-repellent state, that the bulk of their leg is not wetted, but rather contact with the water arises exclusively through individual hairs. Maintaining this water-repellent state requires that the speed of their driving legs does not exceed a critical wetting speed. Flow visualization reveals that the wakes of most water walkers are characterized by a series of coherent subsurface vortices shed by the driving stroke. A theoretical framework is developed in order to describe the propulsion in terms of the transfer of forces and momentum between the creature and its environment. The application of the conservation of momentum to biolocomotion at the interface confirms that the propulsion of water walkers may be rationalized in terms of the subsurface flows generated by their driving stroke. The two principal modes of propulsion available to small water walkers are elucidated. At driving leg speeds in excess of the capillary wave speed, macroscopic curvature forces are generated by deforming the meniscus, and the surface behaves effectively as a trampoline. For slower speeds, the driving legs need not substantially deform the surface but may instead simply brush it: the resulting contact or viscous forces acting on the leg hairs crossing the interface serve to propel the creature forward.

APA, Harvard, Vancouver, ISO, and other styles

47

Loudon, C., and M. A. Koehl. "Sniffing by a silkworm moth: wing fanning enhances air penetration through and pheromone interception by antennae." Journal of Experimental Biology 203, no. 19 (October 1, 2000): 2977–90. http://dx.doi.org/10.1242/jeb.203.19.2977.

Full text

Abstract:

Many organisms increase the air or water flow adjacent to olfactory surfaces when exposed to appropriate chemical stimuli; such ‘sniffing’ samples fluid from a specific region and can increase the rate of interception of odorant molecules. We used hot-wire anemometry, high-speed videography and flow visualization to study air flow near the feathery olfactory antennae of male silkworm moths (Bombyx mori L.). When exposed to conspecific female sex pheromone, male B. mori flap their wings through a stroke angle of 90–110 degrees at approximately 40 Hz without flying. This behavior generates an unsteady flow of air (mean speed 0.3-0.4 m s(−1)) towards the antennae from the front of the male. A pulse of peak air speed occurs at each wing upstroke. The Womersley number (characterizing the damping of pulsatile flow through the gaps between the sensory hairs on the antennae) is less than 1; hence, pulses of faster air (at 40 Hz) should move between sensory hairs. Calculation of flow through arrays of cylinders suggest that this wing fanning can increase the rate of interception of pheromone by the sensory hairs on the antennae by at least an order of magnitude beyond that in still air. Although wing fanning produces air flow relative to the antennae that is approximately 15 times faster than that generated by walking at top speed (0.023 m s(−1)), air flow through the gaps between the sensory hairs is approximately 560 times faster because a dramatic increase in the leakiness of the feathery antennae to air flow occurs at the air velocities produced by fanning.

APA, Harvard, Vancouver, ISO, and other styles

48

Jenks, Robert A., Ashkan Vaziri, Ali-Reza Boloori, and Garrett B. Stanley. "Self-Motion and the Shaping of Sensory Signals." Journal of Neurophysiology 103, no. 4 (April 2010): 2195–207. http://dx.doi.org/10.1152/jn.00106.2009.

Full text

Abstract:

Sensory systems must form stable representations of the external environment in the presence of self-induced variations in sensory signals. It is also possible that the variations themselves may provide useful information about self-motion relative to the external environment. Rats have been shown to be capable of fine texture discrimination and object localization based on palpation by facial vibrissae, or whiskers, alone. During behavior, the facial vibrissae brush against objects and undergo deflection patterns that are influenced both by the surface features of the objects and by the animal's own motion. The extent to which behavioral variability shapes the sensory inputs to this pathway is unknown. Using high-resolution, high-speed videography of unconstrained rats running on a linear track, we measured several behavioral variables including running speed, distance to the track wall, and head angle, as well as the proximal vibrissa deflections while the distal portions of the vibrissae were in contact with periodic gratings. The measured deflections, which serve as the sensory input to this pathway, were strongly modulated both by the properties of the gratings and the trial-to-trial variations in head-motion and locomotion. Using presumed internal knowledge of locomotion and head-rotation, gratings were classified using short-duration trials (<150 ms) from high-frequency vibrissa motion, and the continuous trajectory of the animal's own motion through the track was decoded from the low frequency content. Together, these results suggest that rats have simultaneous access to low- and high-frequency information about their environment, which has been shown to be parsed into different processing streams that are likely important for accurate object localization and texture coding.

APA, Harvard, Vancouver, ISO, and other styles

49

Lidstone, Daniel E., Louise M. Porcher, Jessica DeBerardinis, Janet S. Dufek, and Mohamed B. Trabia. "Concurrent Validity of an Automated Footprint Detection Algorithm to Measure Plantar Contact Area During Walking." Journal of the American Podiatric Medical Association 109, no. 6 (November 1, 2019): 416–25. http://dx.doi.org/10.7547/17-118.

Full text

Abstract:

Background: Monitoring footprints during walking can lead to better identification of foot structure and abnormalities. Current techniques for footprint measurements are either static or dynamic, with low resolution. This work presents an approach to monitor the plantar contact area when walking using high-speed videography. Methods: Footprint images were collected by asking the participants to walk across a custom-built acrylic walkway with a high-resolution digital camera placed directly underneath the walkway. This study proposes an automated footprint identification algorithm (Automatic Identification Algorithm) to measure the footprint throughout the stance phase of walking. This algorithm used coloration of the plantar tissue that was in contact with the acrylic walkway to distinguish the plantar contact area from other regions of the foot that were not in contact. Results: The intraclass correlation coefficient (ICC) demonstrated strong agreement between the proposed automated approach and the gold standard manual method (ICC = 0.939). Strong agreement between the two methods also was found for each phase of stance (ICC > 0.78). Conclusions: The proposed automated footprint detection technique identified the plantar contact area during walking with strong agreement with a manual gold standard method. This is the first study to demonstrate the concurrent validity of an automated identification algorithm to measure the plantar contact area during walking.

APA, Harvard, Vancouver, ISO, and other styles

50

Kolmann, Matthew A., Kenneth C. Welch, Adam P. Summers, and Nathan R. Lovejoy. "Always chew your food: freshwater stingrays use mastication to process tough insect prey." Proceedings of the Royal Society B: Biological Sciences 283, no. 1838 (September 14, 2016): 20161392. http://dx.doi.org/10.1098/rspb.2016.1392.

Full text

Abstract:

Chewing, characterized by shearing jaw motions and high-crowned molar teeth, is considered an evolutionary innovation that spurred dietary diversification and evolutionary radiation of mammals. Complex prey-processing behaviours have been thought to be lacking in fishes and other vertebrates, despite the fact that many of these animals feed on tough prey, like insects or even grasses. We investigated prey capture and processing in the insect-feeding freshwater stingray Potamotrygon motoro using high-speed videography. We find that Potamotrygon motoro uses asymmetrical motion of the jaws, effectively chewing, to dismantle insect prey. However, CT scanning suggests that this species has simple teeth. These findings suggest that in contrast to mammalian chewing, asymmetrical jaw action is sufficient for mastication in other vertebrates. We also determined that prey capture in these rays occurs through rapid uplift of the pectoral fins, sucking prey beneath the ray's body, thereby dissociating the jaws from a prey capture role. We suggest that the decoupling of prey capture and processing facilitated the evolution of a highly kinetic feeding apparatus in batoid fishes, giving these animals an ability to consume a wide variety of prey, including molluscs, fishes, aquatic insect larvae and crustaceans. We propose Potamotrygon as a model system for understanding evolutionary convergence of prey processing and chewing in vertebrates.

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'High-speed Videography'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles