scholarly journals Lightning-induced high temperature and pressure microstructures in surface and subsurface fulgurites

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Li-Wei Kuo ◽  
Steven A. F. Smith ◽  
Chien-Chih Chen ◽  
Ching-Shun Ku ◽  
Ching-Yu Chiang ◽  
...  

AbstractCloud-to-ground lightning causes both high-temperature and high-pressure metamorphism of rocks, forming rock fulgurite. We demonstrate that a range of microstructural features indicative of high temperatures and pressures can form in fulgurites at the surface and in fractures up to several meters below the surface. In comparison to a granite reference sample collected from a borehole at a depth of 138 m, microstructures in both the surface and fracture fulgurite are characterized by: (i) the presence of glass, (ii) a phase transformation in K-feldspar with the presence of exsolution lamellae of plagioclase, and (iii) high residual stresses up to 1.5 GPa. Since this is the first time that fracture-related fulgurite has been described, we also carried out a 1-D numerical model to investigate the processes by which these can form. The model shows that the electric current density in fractures up to 40 m from the landing point can be as high as that on the surface, providing an explanation for the occurrence of fracture-related fulgurites. Our work broadens the near-surface environments in which rock fulgurite has been reported, and provides a detailed description of microstructures that can be compared to those formed during other types of extreme metamorphic events.

2013 ◽  
Vol 457-458 ◽  
pp. 423-427
Author(s):  
Xiao Qing Li ◽  
Xiao Yan Liu

With the development of oilfield exploration, the performance of electric submersible pump (ESP) has been enhanced very fast. It requires testing techniques develop at the same time. The most outstanding question is the testing of high temperature and pressure ESP. A testing well was drilled in Daqing in 1992. It keeps the water liquid state on 150 centigrade by high pressure. This system can simulate operational mode 3000 meters under the ground. But many new ESPs have been produced these years. The quondam testing system couldnt meet the testing requirement. A new testing system is desiderated eagerly. This paper developed a high temperature and pressure ESP testing experimentation system. Hydraulic/thermodynamic analysis calculation has been carried on. Friction resistance from constant pressure point to the suction inlet of hot water pump and the ESP in heating-forced cycle and experimentation primary cycle are calculated respectively. Keeping the water liquid state on 180 centigrade, constant pressure value was fixed on 2.5 MPa. The heat load is calculated including the heat that the water in the system and the equipment need and the heat loss. In order to protect ESP from emanating too much heat to keep the temperature and pressure of the system steady, heat exchange system has been designed. Cold load and heat exchange square have been calculated. Friction resistance and the size of the cold water cistern have been calculated. These provide necessary academic foundation for the testing experimentation of high temperature and pressure ESP.


2017 ◽  
Vol 2017 (1) ◽  
pp. 000526-000530
Author(s):  
M. Barlow ◽  
A. M. Francis ◽  
J. Holmes

Abstract Silicon carbide integrated circuits have demonstrated the ability to function at temperatures as high as 600 °C for extended periods of time. Many environments where high temperature in-situ electronics are desired also have large pressures as well. While some validation has been done for high pressure environments, limited information on the parametric impact of pressure on SiC integrated circuits is available. This paper takes two leading-edge SiC integrated circuit processes using two different classes of devices (JFET and CMOS), and measures the performance through temperature and pressure variation. Circuit functionality was verified at high temperature (475 °C) as well as high pressure (1700 psig).


2017 ◽  
Vol 46 (44) ◽  
pp. 15415-15423 ◽  
Author(s):  
Helen Y. Playford ◽  
Craig L. Bull ◽  
Matthew G. Tucker ◽  
Nicholas P. Funnell ◽  
Christopher J. Ridley ◽  
...  

The formation of the spin-ice pyrochlore Ho2Ge2O7 by two different high temperature, high pressure routes has been explored using in situ neutron diffraction.


1980 ◽  
Vol 43 (329) ◽  
pp. 579-581 ◽  
Author(s):  
S. Kuge ◽  
M. Koizumi ◽  
Y. Miyamoto ◽  
H. Takubo ◽  
S. Kume

SummaryWhen diamond is synthesized at conditions of comparatively high temperature and pressure, the nucleation rate is high, as is the growth rate of the nuclei. Consequently the product is usually an aggregate of crystals with dendritic or skeletal structure. In this study the presence of gold or silver as an additive mixed with a catalyst was found to have the effect of suppressing nucleation. When a homogeneous mixture of graphite, catalyst, and additive was treated at conditions where skeletons and dendrites were produced in the absence of additive, euhedral crystals of octahedra were formed. When a special cell assemblage for high pressure experiments, in which the graphite was placed inside a cylinder of catalyst coated with additive, was used, prismatic and tabular crystals were synthesized.


2018 ◽  
Vol 213 ◽  
pp. 207-214 ◽  
Author(s):  
Michael Hack ◽  
Wolfgang Korte ◽  
Stefan Sträßer ◽  
Matthias Teschner

1999 ◽  
Vol 122 (1) ◽  
pp. 22-26 ◽  
Author(s):  
M. Law ◽  
W. Payten ◽  
K. Snowden

Modeling of welded joints under creep conditions with finite element analysis was undertaken using the theta projection method. The results were compared to modeling based on a simple Norton law. Theta projection data extends the accuracy and predictive capability of finite element modeling of critical structures operating at high temperature and pressure. In some cases analyzed, it was found that the results diverged from those gained using a Norton law creep model. [S0094-9930(00)00601-6]


2020 ◽  
Author(s):  
Dapeng Wen ◽  
Yongfeng Wang ◽  
Junfeng Zhang ◽  
Pengxiao Li ◽  
Zhen-Min Jin

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