scholarly journals Experimental study on variation law of electrical parameters and temperature rise effect of coal under DC electric field

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yunpeng Yang ◽  
Zhihui Wen ◽  
Leilei Si ◽  
Xiangyu Xu
Keyword(s):  
Electric Field ◽  
Temperature Rise ◽  
Experimental System ◽  
Gas Production ◽  
Breakdown Field ◽  
Coal Surface ◽  
Electrical Parameters ◽  
Slow Cooling ◽  
Microstructural Changes ◽  
Anthracite Coal

AbstractJoule heats which are generated by coals in an applied electric field are directly correlated with variation resistivity of electrical parameters of coals. Moreover, the joule heating effect is closely related with microstructural changes and relevant products of coal surface. In the present study, a self-developed applied direct current (DC) field was applied onto an experimental system of coals to investigate variation resistivity of electrical parameters of highly, moderately and lowly metamorphic coal samples. Moreover, breakdown voltages and breakdown field intensities of above three coal samples with different metamorphic grades were tested and calculated. Variation resistivity of electrical parameters of these three coal samples in 2 kV and 4 kV DC fields were analyzed. Results show that internal current of all coal samples increases continuously and tends to be stable gradually after reaching the “inflection point” at peak. The relationship between temperature rise effect on anthracite coal surface in an applied DC field and electrical parameters was discussed. The temperature rise process on anthracite coal surface is composed of three stages, namely, slowly warming, rapid warming and slow cooling to stabilize. The temperature rise effect on anthracite coal surface lags behind changes of currents which run through coal samples. There’s uneven temperature distribution on anthracite coal surface, which is attributed to the heterogeneity of coal samples. In the experiment, the highest temperature on anthracite coal surface 65.8 ℃ is far belower than the lowest temperature for pyrolysis-induced gas production of coals 200 ℃. This study lays foundations to study microstructural changes and relevant products on coal surface in an applied DC field.

scholarly journals Experimental Study on Variation Laws of Electrical Parameters and Surface Temperature Rise Effect of Coal Samples in An Applied Direct Current Field

2020 ◽  
Author(s):  
yunpeng Yang ◽  
zhihui Wen ◽  
leilei Si ◽  
xiangyu Xu
Keyword(s):  
Direct Current ◽  
Temperature Rise ◽  
Experimental System ◽  
Gas Production ◽  
Breakdown Field ◽  
Coal Surface ◽  
Electrical Parameters ◽  
Slow Cooling ◽  
Microstructural Changes ◽  
Anthracite Coal

Abstract Joule heats which are generated by coals in an applied electric field are directly correlated with variation laws of electrical parameters of coals. Moreover, the joule heating effect is closely related with microstructural changes and relevant products of coal surface. In the present study, a self-developed applied direct current (DC) field was applied onto an experimental system of coals to investigate variation laws of electrical parameters of highly, moderately and lowly metamorphic coal samples. Moreover, breakdown voltages and breakdown field intensities of above three coal samples with different metamorphic grades were tested and calculated. Variation laws of electrical parameters of these three coal samples in 2kV and 4kV DC fields were analyzed. Results show that internal current of all coal samples increases continuously and tends to be stable gradually after reaching the “inflection point” at peak. The relationship between temperature rise effect on anthracite coal surface in an applied DC field and electrical parameters was discussed. The temperature rise process on anthracite coal surface is composed of three stages, namely, slowly warming, rapid warming and slow cooling to stabilize. The temperature rise effect on anthracite coal surface lags behind changes of currents which run through coal samples. There’s uneven temperature distribution on anthracite coal surface, which is attributed to the heterogeneity of coal samples. In the experiment, the highest temperature on anthracite coal surface 65.8℃ is far belower than the lowest temperature for pyrolysis-induced gas production of coals 200℃. This study lays foundations to study microstructural changes and relevant products on coal surface in an applied DC field.

Effect of Three-Dimensional Electric Field and Heat Conduction to Electrodes on the Temperature Rise During Irreversible Electroporation

2011 ◽  
Author(s):  
Seiji Nomura ◽  
Kosaku Kurata ◽  
Hiroshi Takamatsu
Keyword(s):  
Heat Conduction ◽  
Electric Field ◽  
Temperature Rise ◽  
Heat Conduction Equation ◽  
Thermal Damage ◽  
Irreversible Electroporation ◽  
Three Dimensional ◽  
End Effects ◽  
Abnormal Cells ◽  
Novel Method

The irreversible electroporation (IRE) is a novel method to ablate abnormal cells by applying a high voltage between two electrodes that are stuck into abnormal tissues. One of the advantages of the IRE is that the extracellular matrix (ECM) may be kept intact, which is favorable for healing. For a successful IRE, it is therefore important to avoid thermal damage of ECM resulted from the Joule heating within the tissue. A three-dimensional (3-D) analysis was conducted in this study to predict temperature rise during the IRE. The equation of electric field and the heat conduction equation were solved numerically by a finite element method. It was clarified that the highest temperature rise occurred at the base of electrodes adjacent to the insulated surface. The result was significantly different from a two-dimensional (2-D) analysis due to end effects, suggesting that the 3-D analysis is required to determine the optimal condition.

scholarly journals Analysis of Pole-Ascending–Descending Action by Insects Subjected to High Voltage Electric Fields

Insects ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 187 ◽  
Author(s):  
Yoshinori Matsuda ◽  
Yoshihiro Takikawa ◽  
Koji Kakutani ◽  
Teruo Nonomura ◽  
Hideyoshi Toyoda
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Negative Charge ◽  
Sitophilus Oryzae ◽  
Experimental System ◽  
Insect Behavior ◽  
Free Electrons ◽  
Current Voltage ◽  
Direct Current Voltage ◽  
Oppositely Charged

The present study was conducted to establish an electrostatic-based experimental system to enable new investigations of insect behavior. The instrument consists of an insulated conducting copper ring (ICR) linked to a direct current voltage generator to supply a negative charge to an ICR and a grounded aluminum pole (AP) passed vertically through the center of the horizontal ICR. An electric field was formed between the ICR and the AP. Rice weevil (Sitophilus oryzae) was selected as a model insect due to its habit of climbing erect poles. The electric field produced a force that could be imposed on the insect. In fact, the negative electricity (free electrons) was forced out of the insect to polarize its body positively. Eventually, the insect was attracted to the oppositely charged ICR. The force became weaker on the lower regions of the pole; the insects sensed the weaker force with their antennae, quickly stopped climbing, and retraced their steps. These behaviors led to a pole-ascending–descending action by the insect, which was highly reproducible and precisely corresponded to the changed expansion of the electric field. Other pole-climbing insects including the cigarette beetle (Lasioderma serricorne), which was shown to adopt the same behavior.

Analysis and correction on frictional temperature rise testing of brake based on preset thermometry method

2019 ◽  
Vol 71 (7) ◽  
pp. 907-914 ◽  
Author(s):  
Shaodi Zhao ◽  
Yan Yin ◽  
Jiusheng Bao ◽  
Xingming Xiao ◽  
Zengsong Li ◽  
...  
Keyword(s):  
Temperature Rise ◽  
Prediction Method ◽  
Experimental System ◽  
Hysteresis Phenomenon ◽  
Content Type ◽  
Braking Performance ◽  
Friction Temperature ◽  
Brake Performance ◽  
Temperature Test ◽  
Real Temperature

Purpose The friction between brake pair causes an intense temperature rise on interface during braking, which affects the braking performance seriously. Therefore, building an accurate testing method for frictional temperature rise (FTR) is a prerequisite. Design/methodology/approach Facing braking conditions of automobiles, an experimental system for testing of FTR based on preset thermometry method (PTM) was established. The FTR was collected by the PTM and the variation laws as well as the cause of errors were analyzed by experiments. The deviations between tested and real temperature were corrected based on tribology and heat theories. Finally, an online prediction method for FTR was pointed out. Findings After correction, the temperature curve accords well with the laws of tribology and thermal theories. The corrected FTR at braking end point is approximately equal to the authentic temperature test by hand thermometer. Originality/value This study eliminated the hysteresis phenomenon of temperature rise sequence and lays a foundation for online accurate monitoring and warning of brake friction temperature rise. It has important theoretical and practical value for expanding the monitoring and improvement of brake performance.

Microstructural changes during the slow-cooling annealing of nanocrystalline SmCo 2:17 type magnets

2013 ◽  
Vol 551 ◽  
pp. 312-317 ◽  
Author(s):  
S.A. Romero ◽  
M.F. de Campos ◽  
J.A. de Castro ◽  
A.J. Moreira ◽  
F.J.G. Landgraf
Keyword(s):  
Slow Cooling ◽  
Microstructural Changes

Use of Cellular Automata for Modelling of the Material Erosion and Grit Entrainment during Discharge in EDM

2014 ◽  
Vol 354 ◽  
pp. 101-108 ◽  
Author(s):  
Andrzej Golabczak ◽  
Andrzej Konstantynowicz ◽  
Marcin Golabczak
Keyword(s):  
Mathematical Model ◽  
Electric Field ◽  
Electric Field Distribution ◽  
Mutual Influence ◽  
Rectangular Grid ◽  
Physical Processes ◽  
Electrical Parameters ◽  
Electro Discharge Machining ◽  
Material Erosion ◽  
Electric Charge Distribution

A combined mathematical model has been presented to evaluate the main physical processes taking place in the electro-discharge machining (EDM) gap. The model consists of electric field distribution evaluation by using the full Poisson equation for the environment of different electrical parameters as well as the electric charge distribution, and rends particles (grits) movement in the gap forced by diffusion as well as the electric field drag of charged grits. Both models are developed on the same rectangular grid which allows mutual influence of them.

scholarly journals Technology for thermostimulated diagnostics of anisotropy and optical axes of crystals

2020 ◽  
Vol 23 (2) ◽  
pp. 99-108 ◽  
Author(s):  
V. M. Timokhin ◽  
V. M. Garmash ◽  
V. A. Tedzhetov
Keyword(s):  
Relaxation Time ◽  
Melting Point ◽  
Electric Field ◽  
Liquid Nitrogen ◽  
Optical Axis ◽  
Sixth Order ◽  
Breakdown Field ◽  
Optical Axes ◽  
Polarization Temperature ◽  
Thermally Stimulated Depolarization

To implement the technology of thermally stimulated diagnostics of anisotropy and optical axes of crystals, the sample is thermostated at a temperature not exceeding the melting point, an electric field not exceeding the breakdown field is applied to the sample, polarization is produced for a time greater than the relaxation time at this temperature. After that, without disconnecting the electric field, cooling to the temperature of liquid nitrogen is performed, then the field is switched off, the sample is linearly heated to a temperature above the polarization temperature and the obtained thermally stimulated depolarization (TSD) spectra taken along and perpendicular to the optical axis of the sixth order C6 crystal are examined. When comparing the obtained spectra, the presence of anisotropy is determined, and the exact direction of the optical axes is determined by the magnitude and presence of the TSD maxima.

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