A note on the formation of fulgurites

1980 ◽  
Vol 117 (3) ◽  
pp. 293-296 ◽  
Author(s):  
D. J. Williams ◽  
W. Johnson

SummaryA phenomenon similar to the sand tube fulgurite has been observed in experimental work carried out to compact and sinter metal powders using high voltage discharges. The sand tube fulgurite is a fused quartz tube formed by the passage of a lightning discharge. Further experiments, in which a high voltage discharge was passed from a pointed electrode held above a large volume of copper powder, through to an earthed plate, give a copper product with the characteristic fulgurite morphology. This result suggests that the quartz sand can behave as a good conductor in the lightning discharge, perhaps due to conducting coatings on the surface of the sand particles.

2019 ◽  
Vol 45 (6) ◽  
pp. 527-536 ◽  
Author(s):  
A. V. Strikovskiy ◽  
S. V. Korobkov ◽  
M. E. Gushchin ◽  
A. A. Evtushenko ◽  
I. Yu. Zudin

2017 ◽  
Vol 50 (16) ◽  
pp. 165202 ◽  
Author(s):  
A V Agafonov ◽  
V A Bogachenkov ◽  
A P Chubenko ◽  
A V Oginov ◽  
A A Rodionov ◽  
...  

Plasma ◽  
2021 ◽  
Vol 4 (2) ◽  
pp. 309-331
Author(s):  
Wahyu Diono ◽  
Siti Machmudah ◽  
Hideki Kanda ◽  
Yaping Zhao ◽  
Motonobu Goto

The application of high-voltage discharge plasma for water pollutant decomposition and the synthesis of nanoparticles under a high-pressure argon gas environment (~4 MPa) was demonstrated. The experiments were carried out in a batch-type system at room temperature with a pulsed DC power supply (15.4 to 18.6 kV) as a discharge plasma source. The results showed that the electrode materials, the pulsed repetition rates, the applied number of pulses, and the applied voltages had a significant effect on the degradation reactions of organic compounds. Furthermore, carbon solid materials from glycine decomposition were generated during the high-voltage discharge plasma treatment under high-pressure conditions, while Raman spectra and the HRTEM images indicated that titanium dioxide with a brookite structure and titanium carbide nanoparticles were also formed under these conditions. It was concluded that this process is applicable in practice and may lead to advanced organic compound decomposition and metal-based nanoparticle synthesis technologies.


2012 ◽  
Vol 37 (2) ◽  
pp. 259 ◽  
Author(s):  
Kaimin Guo ◽  
Jingquan Lin ◽  
Zuoqiang Hao ◽  
Xun Gao ◽  
Zhenming Zhao ◽  
...  

2007 ◽  
Vol 539-543 ◽  
pp. 2657-2662 ◽  
Author(s):  
Michael Nöthe ◽  
Matthias Schulze ◽  
Rainer Grupp ◽  
Bernd Kieback ◽  
A. Haibel

The two-particle model describes the approach of particle centres and the growth of the interparticle contacts during sintering of metal powders. Unfortunately the comprehensive description of processes inside of three dimensional specimens must consider the contribution of particle rearrangements. The recent developments of combined micro focus computed tomography (CT) and 3D photogrammetric image analyzing give the opportunity to obtain the experimental data required to overcome the shortcomings of sintering theories based on the two-particle model. The analysis of spherical poly and single crystalline copper powder was performed by CT. In addition a single crystal specimen was analyzed by high resolution synchrotron radiation tomography - a more sophisticated analysis method with very limited availability. The analysis of the 3D tomographic image by photogrammetric image analyzing yielded the positions and radii of all particles and their contact partners as well. A statistical analysis of the retrieved data was performed. The formation and breaking of necks during sintering could be observed. An in-depth analysis of the particle rotation with respect to the coordination number and local density will be presented.


2007 ◽  
Vol 46 (17) ◽  
pp. 5469-5477 ◽  
Author(s):  
Le C. Lei ◽  
Yi Zhang ◽  
Xing W. Zhang ◽  
Ying X. Du ◽  
Qi Z. Dai ◽  
...  

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