scholarly journals Experimental Motion Analysis of Radially Rotating Beams Using High-Speed Camera and Motion Analyzer

1996 ◽  
Vol 3 (4) ◽  
pp. 293-301
Author(s):  
K.H. Low ◽  
Michael W.S. Lau ◽  
K.K. Low
Keyword(s):  
Strain Measurement ◽  
Vibration Analysis ◽  
High Speed ◽  
Reference Points ◽  
The Other ◽  
Strain Gauges ◽  
High Speed Camera ◽  
Flexible Beams ◽  
Vibrating Beams ◽  
Vibration Parameters

Although strain gauges can be attached to a system for vibration analysis, wires connected to the strain gauges may disturb the system and affect the accuracy of the strain measurement. As an alternative, this work presents the use of a high-speed camera combined with a motion analyzer to study the motion of rotating flexible beams. One end of the beam is rigidly connected to a motor, while the other end is free. White stickers placed on selected points on a given beam are the reference points in a digitization process. The modes of the vibrating beams can be filmed and analyzed. The vibration parameters, such as deflection and frequency, can be obtained by using a film motion analyzer. The results show that the beam does not behave in a clamped-free or a pinned-free fashion, but instead occurs at an intermediate boundary between these two classical conditions.

scholarly journals Leader-chasing behavior in negative artificial triggered lightning flashes

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Fukun Wang ◽  
Jianguo Wang ◽  
Li Cai ◽  
Rui Su ◽  
Wenhan Ding ◽  
...  
Keyword(s):  
High Speed ◽  
The Other ◽  
Lightning Flash ◽  
High Speed Camera ◽  
Return Stroke ◽  
Catching Up ◽  
Special Cases ◽  
Triggered Lightning

AbstractTwo special cases of dart leader propagation were observed by the high-speed camera in the leader/return stroke sequences of a classical triggered lightning flash and an altitude-triggered lightning flash, respectively. Different from most of the subsequent return strokes preceded by only one leader, the return stroke in each case was preceded by two leaders occurring successively and competing in the same channel, which herein is named leader-chasing behavior. In one case, the polarity of the latter leader was opposite to that of the former leader and these two combined together to form a new leader, which shared the same polarity with the former leader. In the other case, the latter leader shared the same polarity with the former leader and disappeared after catching up with the former leader. The propagation of the former leader in this case seems not to be significantly influenced by the existence of the latter leader.

scholarly journals The effect of a lack of uncapped brood on social interactions between honey bee workers and the queen

Apidologie ◽  
2021 ◽  
Author(s):  
Sylwia Łopuch ◽  
Adam Tofilski
Keyword(s):  
Social Interactions ◽  
Honey Bee ◽  
Honey Bees ◽  
High Speed ◽  
Egg Production ◽  
Social Contexts ◽  
The Other ◽  
High Speed Camera ◽  
Time Required ◽  
Honey Bee Workers

AbstractVibro-acoustic communication is used by honey bees in many different social contexts. Our previous research showed that workers interact with their queen outside of the swarming period by means of wing-beating behaviour. Therefore, the aim of this study was to verify the hypothesis that the wing-beating behaviour of workers attending the queen stimulates her to lay eggs. The behaviour of workers and the queen was recorded using a high-speed camera, at first in the presence of uncapped brood in the nest and then without one. None of the queens performed wing-beating behaviour. On the other hand, the workers attending the queen demonstrated this behaviour two times per minute, on average, even in the presence of uncapped brood in the nest. After removing the combs with the uncapped brood, the incidence of wing-beating behaviour increased significantly to an average of four times per minute. Wing-beating behaviour did not differ significantly in its characteristics when uncapped brood was present or absent in the nest. During 3 days after removing the combs with the uncapped brood, there was no significant increase in the rate of egg lying by the queen. Therefore, the results presented here do not convincingly confirm that the wing-beating behaviour of workers affects the rate of queen's egg-lying. This negative result can be related to colony disturbance and longer time required by the queen to increase egg production.

Mouth Shape Detection Based on Template Matching and Optical Flow for Machine Lip Reading

2013 ◽  
Vol 1 (1) ◽  
pp. 14-25 ◽  
Author(s):  
Tsuyoshi Miyazaki ◽  
Toyoshiro Nakashima ◽  
Naohiro Ishii
Keyword(s):  
Optical Flow ◽  
Template Matching ◽  
High Speed ◽  
Image Sequences ◽  
Previous Method ◽  
The Other ◽  
High Speed Camera ◽  
Improved Method ◽  
Time Period ◽  
Lip Reading

The authors describe an improved method for detecting distinctive mouth shapes in Japanese utterance image sequences. Their previous method uses template matching. Two types of mouth shapes are formed when a Japanese phone is pronounced: one at the beginning of the utterance (the beginning mouth shape, BeMS) and the other at the end (the ending mouth shape, EMS). The authors’ previous method could detect mouth shapes, but it misdetected some shapes because the time period in which the BeMS was formed was short. Therefore, they predicted that a high-speed camera would be able to capture the BeMS with higher accuracy. Experiments showed that the BeMS could be captured; however, the authors faced another problem. Deformed mouth shapes that appeared in the transition from one shape to another were detected as the BeMS. This study describes the use of optical flow to prevent the detection of such mouth shapes. The time period in which the mouth shape is deformed is detected using optical flow, and the mouth shape during this time is ignored. The authors propose an improved method of detecting the BeMS and EMS in Japanese utterance image sequences by using template matching and optical flow.

scholarly journals A survey on the effects of bumpy road on the vibration of multi-purpose forest fire fighting vehicle

2021 ◽  
Vol 9 (3) ◽  
pp. 291-298 ◽  
Author(s):  
Nguyen Thanh Tung ◽  
Luong Van Van ◽  
Nguyen Thanh Quang
Keyword(s):  
High Pressure ◽  
Forest Fire ◽  
Vibration Analysis ◽  
High Speed ◽  
Fire Fighting ◽  
Wheel Drive ◽  
Moving Vehicles ◽  
Pressure Water ◽  
Vibration Parameters ◽  
Water Pumps

Multi-purpose forest fire fighting vehicles should carry a set of firefighting equipment such as high-pressure water pumps, tree cutters to create a fire isolation corridor, vacuum, and blowing machine high-speed wind sandblasting devices etc. The bumpy road and velocity of moving vehicles can affect the vibration response of these vehicles. Hence, in this research the vibration analysis of a Multi-purpose forest fire fighting vehicle mounted on a URAL4320 active three-wheel drive vehicle is simulated and analyzed. The effect of road bumping and speed of vehicle on the vibration parameters are studied via building mathematical models with 19 degree of freedom for simulating the suspension system of the investigated vehicle.

scholarly journals Comparison of a Lightweight Experimental Shaker and an Orchard Tractor Mounted Trunk Shaker for Fresh Market Citrus Harvesting

Agriculture ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1092
Author(s):  
Coral Ortiz ◽  
Antonio Torregrosa ◽  
Sergio Castro-García
Keyword(s):  
Removal Efficiency ◽  
High Speed ◽  
Experimental Device ◽  
High Speed Camera ◽  
Time Increase ◽  
Fresh Market ◽  
Harvesting Systems ◽  
Vibration Time ◽  
Vibration Parameters ◽  
Citrus Harvesting

A designed lightweight experimental shaker successfully used to collect ornamental oranges has been tested to harvest fresh market citrus. The aim of this study was to evaluate the removal efficiency and operational times of this experimental device compared to an orchard trunk shaker. Three different collecting systems were studied. ‘Caracara’ citrus trees were tested. Removal efficiency, vibration parameters, fruit and tree damages, and fruit quality were measured. A high-speed camera was used to record operational times and determine cumulative removal percentage over vibration time. The canvases on the ground reduced the severe fruit damages but were not useful to protect against light damages. The experimental shaker produced a higher percentage of slightly damaged oranges. No significant differences in removal efficiency were found between the two harvesting systems. However, removal efficiency using the experimental device could be reduced by 40 percent and working time increase by more than 50 percent when access to the main branches was difficult. In agreement with previous results, the curve representing the branch cumulative removal percentage in time followed a sigmoidal pattern. A model was built showing that during the first 5 s more than 50 percent of the fruits were detached.

Laser Processing of Asteroid Simulants

2020 ◽  
Author(s):  
Niklas Anthony ◽  
Mikael Granvik ◽  
Christina Wanhainen ◽  
Jan Frostevarg ◽  
Heikki Suhonen ◽  
...  
Keyword(s):  
Energy Efficient ◽  
Laser Processing ◽  
High Speed ◽  
The Other ◽  
High Speed Camera ◽  
X Ray ◽  
Nd:Yag Lasers ◽  
Micro Tomography ◽  
Power Densities ◽  
Shed Light

<p>Asteroid mining and redirection are two trends that both can utilize lasers, one to drill and cut, the other to ablate and move. Yet little is known about what happens when a laser is used to process the types of materials we typically expect to find on most asteroids. To shed light on laser processing of asteroid material, we used pulsed Nd:YAG lasers on samples of olivine, pyroxene, and serpentine, and studied the process with a high-speed camera and illumination laser at 10~000~frames~per~second. We also measure the sizes of the resulting holes using X-ray micro-tomography to find the pulse parameters which remove the largest amount of material using the least amount of energy. We find that at these power densities, all three minerals will melt and chaotically throw off spatter. Short, low-power pulses can efficiently produce thin, deep holes, and long, high-power pulses are more energy efficient at removing the most amount of material. We wil also present some preliminary results of the effects of spallation of these materials.</p>

Evolution toward asymmetrical gaits in Neotropical spiny rats (Rodentia: Echimyidae): evidences favoring adaptation

2007 ◽  
Vol 85 (6) ◽  
pp. 709-717 ◽  
Author(s):  
P.L.B. Rocha ◽  
S. Renous ◽  
A. Abourachid ◽  
E. Höfling
Keyword(s):  
Relative Velocity ◽  
High Speed ◽  
Gait Pattern ◽  
The Other ◽  
Time Lags ◽  
High Speed Camera ◽  
Adaptive Value ◽  
Trinomys Yonenagae ◽  
A Minor

The torch tail rat, Trinomys yonenagae Rocha, 1995 (family Echimyidae), is the morphologically most divergent of the spiny rats. In this study, we evaluate the hypothesis that gaits preferentially used by this species evolved as an adaptation to the desert-like dunes where they live. We filmed spontaneous locomotion of T. yonenagae, Trinomys albispinus minor Reis and Pessôa, 1995, and Proechimys cayennensis (Desmarest, 1817) with a high-speed camera. We detected, for each of the 323 cycles of the reference forelimb recorded, the kind of gait developed, the time lags between the touchdown of each pair of limbs, and the relative velocity. Trinomys yonenagae walked twice as fast as P. cayennensis and T. a. minor using mainly the asymmetrical transverse gallop, half-bounds, and bounds, while the other two species used mainly the lateral sequence walk. Gaits changed from symmetrical to asymmetrical with increasing velocity for T. yonenagae but not for the other species. We argue that the gait pattern found in T. yonenagae is autapomorphic, that its origin coincides with the shift to a desert-like habitat, and that this type of gait confers higher adaptive value to explore resources in open areas than the plesiomorphic pattern. Therefore, we conclude that it can be considered adaptive to life in the dunes.

scholarly journals Indirect Measurement of Loading Forces with High-Speed Camera

Sensors ◽  
2021 ◽  
Vol 21 (19) ◽  
pp. 6643
Author(s):  
Krzysztof Mendrok ◽  
Ziemowit Dworakowski ◽  
Kajetan Dziedziech ◽  
Krzysztof Holak
Keyword(s):  
High Speed ◽  
Indirect Measurement ◽  
Strain Gauges ◽  
High Speed Camera ◽  
Load Identification ◽  
Multiple Sensors ◽  
Single Force ◽  
Fbg Sensors ◽  
Diagnostic Module ◽  
Contactless Measurements

In the last few decades, there has been a significant increase in interest in developing, constructing, and using structural health monitoring (SHM) systems. The classic monitoring system should, by definition, have, in addition to the diagnostic module, a module responsible for monitoring loads. These loads can be measured with piezoelectric force sensors or indirectly with strain gauges such as resistance strain gauges or FBG sensors. However, this is not always feasible due to how the force is applied or because sensors cannot be mounted. Therefore, methods for identifying excitation forces based on response measurements are often used. This approach is usually cheaper and easier to implement from the measurement side. However, in this approach, it is necessary to use a network of response sensors, whose installation and wiring can cause technological difficulties and modify the results for slender constructions. Moreover, many load identification methods require the use of multiple sensors to identify a single force history. Increasing the number of sensors recording responses improves the numerical conditioning of the method. The proposed article presents the use of contactless measurements carried out with the help of a high-speed camera to identify the forces exiting the object.

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