scholarly journals High-speed video observations on fork lightning events in Malaysia

2020 ◽  
Vol 19 (3) ◽  
pp. 1620
Author(s):  
Nor Asrina Binti Ramlee ◽  
N. A. Ahmad ◽  
Z. A. Baharudin ◽  
A. R. Mohamed
Keyword(s):  
High Speed ◽  
Temporal Analysis ◽  
Lightning Protection ◽  
Stroke Event ◽  
Time Duration ◽  
Return Stroke ◽  
Lightning Strikes ◽  
High Speed Video ◽  
Three Samples ◽  
Video Observations

Malaysia is one of the countries with the highest lightning strikes incidence in the world. Yet, Malaysians are still taking a proper lightning protection indifferent manner. This might be due to lack of knowledge on lightning characteristics in Malaysia. Therefore, this study presents an unusual lightning phenomenon with multiple grounding points that might cause a disastrous event, called fork lightning. Between November and December 2018, there were three different patterns of fork lightning mechanism successfully recorded by using high speed camera with 2800 frame per second. Temporal analysis of the lightning progress had been done on the samples based only on the camera records which then played back by using Wondershare Filmora video editor. These three samples of fork lightning images were acquired among 37 lightning events recorded in this study. The first sample of fork lightning fully established the forked branch 0.35 ms before the return stroke occurred. On the contrary, second fork lightning established its forked branch 0.35 ms after the return stroke. Both forked branches for third sample simultaneously fully established with the return stroke event. Obviously, these events had striking the ground in up to ten milliseconds of time duration. Thus, there is always a possibility that they might cause serious damage and should not be neglected in designing a lightning protection system.

High Speed Video Observations of Vocal Fold Kinematics While Playing a Clarinet

2021 ◽  
Author(s):  
Andrew L. DiMatteo ◽  
Juergen Neubauer ◽  
David G. Lott ◽  
Stephanie Zacharias ◽  
Thomas Murry ◽  
...  
Keyword(s):  
Vocal Fold ◽  
High Speed ◽  
High Speed Video ◽  
Video Observations

Comparison of acceleration, expansion, and brightness of sprite streamers obtained from modeling and high-speed video observations

2009 ◽  
Vol 114 (A3) ◽  
pp. n/a-n/a ◽  
Author(s):  
N. Y. Liu ◽  
V. P. Pasko ◽  
K. Adams ◽  
H. C. Stenbaek-Nielsen ◽  
M. G. McHarg
Keyword(s):  
High Speed ◽  
High Speed Video ◽  
Video Observations

High-speed Video Observations of Unusual Dart Leaders in Two Natural Lightning Flashes Striking on Canton Tower

2021 ◽  
Author(s):  
Hansheng Cai ◽  
Xiaolei Wang ◽  
Gang Liu ◽  
Minchuan Liao ◽  
Shangmao Hu ◽  
...  
Keyword(s):  
High Speed ◽  
High Speed Video ◽  
Video Observations

scholarly journals Rotational Maneuvers of Copepod Nauplii at Low Reynolds Number

Fluids ◽  
2020 ◽  
Vol 5 (2) ◽  
pp. 78
Author(s):  
Kacie T. M. Niimoto ◽  
Kyleigh J. Kuball ◽  
Lauren N. Block ◽  
Petra H. Lenz ◽  
Daisuke Takagi
Keyword(s):  
Reynolds Number ◽  
Rotational Motion ◽  
High Speed ◽  
The Body ◽  
Three Dimensions ◽  
Linear Path ◽  
Physical Mechanisms ◽  
High Speed Video ◽  
Video Observations ◽  
Principal Axes

Copepods are agile microcrustaceans that are capable of maneuvering freely in water. However, the physical mechanisms driving their rotational motion are not entirely clear in small larvae (nauplii). Here we report high-speed video observations of copepod nauplii performing acrobatic feats with three pairs of appendages. Our results show rotations about three principal axes of the body: yaw, roll, and pitch. The yaw rotation turns the body to one side and results in a circular swimming path. The roll rotation consists of the body spiraling around a nearly linear path, similar to an aileron roll of an airplane. We interpret the yaw and roll rotations to be facilitated by appendage pronation or supination. The pitch rotation consists of flipping on the spot in a maneuver that resembles a backflip somersault. The pitch rotation involved tail bending and was not observed in the earliest stages of nauplii. The maneuvering strategies adopted by plankton may inspire the design of microscopic robots, equipped with suitable controls for reorienting autonomously in three dimensions.

scholarly journals High‐Speed Video Observations of Natural Lightning Attachment Process With Framing Rates up to Half a Million Frames per Second

2019 ◽  
Vol 46 (21) ◽  
pp. 12580-12587 ◽  
Author(s):  
Qi Qi ◽  
Weitao Lyu ◽  
Ying Ma ◽  
Bin Wu ◽  
Lyuwen Chen ◽  
...  
Keyword(s):  
High Speed ◽  
High Speed Video ◽  
Video Observations ◽  
Attachment Process

Statistical Distributions of Lightning Parameters with Emphasis on their Extremely High Values

2021 ◽  
Vol 3 (3) ◽  
pp. 4-25
Author(s):  
Vladimir A. RAKOV ◽  
◽  
Evgeny A. MAREEV ◽  
Keyword(s):  
Extreme Values ◽  
Negative Polarity ◽  
Lightning Protection ◽  
Time Duration ◽  
Return Stroke ◽  
Lightning Channel ◽  
Direct Measurements ◽  
Analysis Of Results ◽  
Wide Scatter ◽  
A Current

The paper is devoted to the review of the data on the lightning parameters necessary for development and perfection of lightning protection systems. It is shown, that down to present time national and international lightning protection standards are based on the Berger’s data on distribution of lightning amplitudes currents. Experimental data on amplitude of the return-stroke current the received recently in Brazil, Japan, USA (Florida) and Austria are resulted. It is emphasized, that the given data on currents of a lightning are characterized by a wide scatter that specifies necessity of realization of the further researches. The detailed description of parameters of the return-stroke peak current, including duration of front time, duration of a pulse, a steepness of a current at the front is given. It is emphasized, that median value of amplitude of a current of the first making the return-stroke in 3-4 times is higher than a current of the subsequent components. The analysis measured median (50%) and severe (1%) values of lighting parameters which are necessary for construction of a curve of distribution in the assumption of its submission lognormal law is carried out. Results of theoretical researches are given according to extreme values of currents of a lightning. It is shown, that, depending on length of the lightning channel (from 4 up to 6 kms), the maximal current can vary from 300 kA up to 500 кА. The minimal value of lightning current is appreciated in 2 кА. The analysis of results of new direct measurements has shown, that for a lightning of positive polarity the maximal current can reach 340 кА, that appreciably is higher than a settlement maximum for a lightning of negative polarity (200 кА). Recent theoretical researches have allowed to prove experimentally received lognormal distribution of currents for lightning of negative polarity.

High-speed video observations of natural cloud-to-ground lightning leaders – A statistical analysis

2014 ◽  
Vol 135-136 ◽  
pp. 285-305 ◽  
Author(s):  
Leandro Z.S. Campos ◽  
Marcelo M.F. Saba ◽  
Tom A. Warner ◽  
Osmar Pinto ◽  
E. Philip Krider ◽  
...  
Keyword(s):  
Statistical Analysis ◽  
High Speed ◽  
High Speed Video ◽  
Video Observations ◽  
Cloud To Ground Lightning
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