High-Speed Photography And Holography Of Laser Induced Breakdown In Liquids

1979 ◽  
Author(s):  
Werner Lauterborn
Keyword(s):  
High Speed ◽  
High Speed Photography ◽  
Laser Induced Breakdown

DETERMINATION SOUND SPEED OF METAL IN AQUEOUS SOLUTION VIA LASER INDUCED ACOUSTIC WAVE TECHNIQUE

2016 ◽  
Vol 78 (3) ◽  
Author(s):  
Maisarah Duralim ◽  
Noriah Bidin ◽  
Waskito Nugroho ◽  
Jasman Zainal
Keyword(s):  
Shock Wave ◽  
Aqueous Solution ◽  
Acoustic Wave ◽  
Sound Speed ◽  
High Speed ◽  
Optical Breakdown ◽  
High Speed Photography ◽  
Nonlinear Phenomena ◽  
Metal Element ◽  
Laser Induced Breakdown

Laser induced breakdown and shock wave propagation are nonlinear phenomena. The high temperature and high pressure associated with plasma formation offering a lot advantages in industrial and scientific research.  However not many realized that the end  product of nonlinear effect such as the generation of acoustic wave will also attribute to significant impact. Thus the intention of this study is to materialize the usefulness of such acoustic wave for determination the sound speed of metal element like Pb, Hg and K in aqueous solution. In this attempt a Q-switched Nd:YAG laser was focused to induce optical breakdown and its associated shock wave generation which later  follow by the generation of acoustic wave. The phenomenon is observed in conjunction with high speed photography based shadowgraph technique. The experimental results of sound speed for K, Hg and Pb is found in good agreement with the standard value from references. This confirmed that laser induced acoustic wave will be other alternative method for measuring sound speed for metal element in periodic table.

CO2 Laser Induced Breakdown and Heating of Hydrogen in a Magnetic Mirror Field Geometry

1975 ◽  
Vol 53 (14) ◽  
pp. 1360-1366 ◽  
Author(s):  
A. A. Offenberger ◽  
N. H. Burnett
Keyword(s):  
Laser Pulse ◽  
High Speed ◽  
Ruby Laser ◽  
Thomson Scattering ◽  
Magnetic Mirror ◽  
High Speed Photography ◽  
Parabolic Mirror ◽  
Laser Induced Breakdown ◽  
Field Geometry ◽  
Breakdown Plasma

A 1 GW, 125 J CO2 laser pulse focussed by a 10 cm f.l. parabolic mirror has been used to induce breakdown and heating in 15 Torr hydrogen along the axis of a short 50 kG magnetic mirror field. Evolution of the breakdown plasma thus produced has been studied by high speed photography, ruby laser Thomson scattering, and a Mach–Zehnder interferometer. Results indicate an efficient radial confinement of plasma by the mirror field with an electron temperature much enhanced over that resulting from a fieldfree breakdown. Interferometric measurements show that breakdown results in a cylindrical plasma with an electron density minimum on axis in both cases. A monitor of the transmitted CO2 laser pulse indicates very incomplete coupling of laser radiation into the plasma column with the field applied, presumably due to refraction losses at the entrance boundary of the breakdown.

Crack divergence phenomena in tempered glass

2020 ◽  
Vol 13 (3) ◽  
pp. 115-129
Author(s):  
Shin’ichi Aratani
Keyword(s):  
Optimal Design ◽  
High Speed ◽  
Glass Plate ◽  
Acute Angle ◽  
Divergence Angle ◽  
High Speed Photography ◽  
Tempered Glass ◽  
Thick Glass

High speed photography using the Cranz-Schardin camera was performed to study the crack divergence and divergence angle in thermally tempered glass. A tempered 3.5 mm thick glass plate was used as a specimen. It was shown that two types of bifurcation and branching existed as the crack divergence. The divergence angle was smaller than the value calculated from the principle of optimal design and showed an acute angle.

Experimental study of hydrodynamic effects in the inverse water hydrocarbon emulsions flow in microchannels

2016 ◽  
Vol 11 (1) ◽  
pp. 30-37 ◽  
Author(s):  
A.A. Rakhimov ◽  
A.T. Akhmetov
Keyword(s):  
High Speed ◽  
Petroleum Industry ◽  
Chemical Compounds ◽  
High Viscosity ◽  
Blocking Effect ◽  
High Speed Photography ◽  
Simple Chemical ◽  
Reported Study ◽  
Dynamic Blocking ◽  
Hydrodynamic Effects

The paper presents results of hydrodynamic and rheological studies of the inverse water hydrocarbon emulsions. The success of the application of invert emulsions in the petroleum industry due, along with the high viscosity of the emulsion, greatly exceeding the viscosity of the carrier phase, the dynamic blocking effect, which consists in the fact that the rate of flow of emulsions in capillary structures and cracks falls with time to 3-4 orders, despite the permanent pressure drop. The reported study shows an increase in viscosity with increasing concentration or dispersion of emulsion. The increase in dispersion of w/o emulsion leads to an acceleration of the onset of dynamic blocking. The use of microfluidic devices, is made by soft photolithography, along with high-speed photography (10,000 frames/s), allowed us to see in the blocking condition the deformation of the microdroplets of water in inverse emulsion prepared from simple chemical compounds.

scholarly journals Prey Capturing Dynamics and Nanomechanically Graded Cutting Apparatus of Dragonfly Nymph

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 559
Author(s):  
Lakshminath Kundanati ◽  
Prashant Das ◽  
Nicola M. Pugno
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
High Speed ◽  
Prey Capture ◽  
High Speed Photography ◽  
Sensory Organs ◽  
Dragonfly Nymph ◽  
Drag Forces ◽  
Predatory Insects ◽  
Dragonfly Nymphs

Aquatic predatory insects, like the nymphs of a dragonfly, use rapid movements to catch their prey and it presents challenges in terms of movements due to drag forces. Dragonfly nymphs are known to be voracious predators with structures and movements that are yet to be fully understood. Thus, we examine two main mouthparts of the dragonfly nymph (Libellulidae: Insecta: Odonata) that are used in prey capturing and cutting the prey. To observe and analyze the preying mechanism under water, we used high-speed photography and, electron microscopy. The morphological details suggest that the prey-capturing labium is a complex grasping mechanism with additional sensory organs that serve some functionality. The time taken for the protraction and retraction of labium during prey capture was estimated to be 187 ± 54 ms, suggesting that these nymphs have a rapid prey mechanism. The Young’s modulus and hardness of the mandibles were estimated to be 9.1 ± 1.9 GPa and 0.85 ± 0.13 GPa, respectively. Such mechanical properties of the mandibles make them hard tools that can cut into the exoskeleton of the prey and also resistant to wear. Thus, studying such mechanisms with their sensory capabilities provides a unique opportunity to design and develop bioinspired underwater deployable mechanisms.

Droplet transfer behavior of narrow gap laser wire filling welding

2019 ◽  
Vol 33 (01n03) ◽  
pp. 1940045 ◽  
Author(s):  
Z. Zhang ◽  
R. Wang ◽  
G. Gou ◽  
H. Chen ◽  
W. Gao
Keyword(s):  
Welding Speed ◽  
High Speed ◽  
Transition Period ◽  
High Speed Photography ◽  
Narrow Gap ◽  
Droplet Transfer ◽  
Transfer Behavior ◽  
Feeding Speed ◽  
Wire Feeding ◽  
Droplet Transition

In this paper, we study the droplet transition behavior of narrow gap laser wire filling welding under the condition of changing welding speed and wire feeding speed, and it was observed by high-speed photography. It was found that with the increase of welding speed, the frequency of droplet transfer was reduced and the transition period was prolonged. With the increase of wire feeding speed, the wire was not fully melted and finally inserted into the molten pool.

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