Journal articles: 'Air Breakdown'

1

Gurevich, A. V., G. M. Milikh, and R. A. Roussel-Dupre. "Nonuniform runaway air-breakdown." Physics Letters A 187, no. 2 (April 1994): 197–203. http://dx.doi.org/10.1016/0375-9601(94)90062-0.

Full text

APA, Harvard, Vancouver, ISO, and other styles

2

Rezinkina, M. M., O. L. Rezinkin, A. R. Danyliuk, V. I. Revuckiy, and A. N. Guchenko. "PHYSICAL MODELING OF ELECTRICAL PHYSICAL PROCESSESAT LONG AIR GAPS BREAKDOWN." Tekhnichna Elektrodynamika 2017, no. 1 (January 15, 2017): 29–34. http://dx.doi.org/10.15407/techned2017.01.029.

Full text

APA, Harvard, Vancouver, ISO, and other styles

3

Rodríguez, A. E., W. L. Morgan, K. J. Touryan, W. M. Moeny, and T. H. Martin. "An air breakdown kinetic model." Journal of Applied Physics 70, no. 4 (August 15, 1991): 2015–22. http://dx.doi.org/10.1063/1.349487.

Full text

APA, Harvard, Vancouver, ISO, and other styles

4

Zhou Dongfang, 周东方, 余道杰 Yu Daojie, 宁辉 Ning Hui, 马弘舸 Ma Hongge, 陈昌华 Chen Changhua, 林竞羽 Lin Jingyu, 魏进进 Wei Jinjin, et al. "Area distribution of HPM air-breakdown." High Power Laser and Particle Beams 26, no. 6 (2014): 63026. http://dx.doi.org/10.3788/hplpb20142606.63026.

Full text

APA, Harvard, Vancouver, ISO, and other styles

5

Roussel-Dupré, R. A., A. V. Gurevich, T. Tunnell, and G. M. Milikh. "Kinetic theory of runaway air breakdown." Physical Review E 49, no. 3 (March 1, 1994): 2257–71. http://dx.doi.org/10.1103/physreve.49.2257.

Full text

APA, Harvard, Vancouver, ISO, and other styles

6

Malov, A. M., and A. N. Orishich. "Optical breakdown in supersonic air jet." Technical Physics Letters 38, no. 1 (January 2012): 70–73. http://dx.doi.org/10.1134/s1063785012010269.

Full text

APA, Harvard, Vancouver, ISO, and other styles

7

Markku Oksanen and Jarmo Hietanen. "Photoacoustic breakdown sound source in air." Ultrasonics 32, no. 5 (September 1994): 327–31. http://dx.doi.org/10.1016/0041-624x(94)90102-3.

Full text

APA, Harvard, Vancouver, ISO, and other styles

8

Wu, Shaocheng, Linong Wang, Jiachen Gao, Cheng Xie, Lei Liu, Tingting Wang, and Enwen Li. "Breakdown characteristics of combined air gaps under lightning impulse." AIP Advances 12, no. 3 (March 1, 2022): 035024. http://dx.doi.org/10.1063/5.0084951.

Full text

Abstract:

With the increase of both voltage level and the transmission capacity, more attention has been paid to the external insulation of transmission lines. As the main external insulation medium of transmission line, the air gap’s dielectric strength will change when there are floating conductors. In this paper, we established an experiment platform to study the effects of floating conductors, simulated by floating rod electrode, on breakdown voltage, breakdown time, electric field distribution and discharge physical process of long air gaps under lightning impulse. The results showed that the intervention of floating electrode reduced the breakdown voltage and breakdown time of long air gaps, and the position with the longest breakdown time was the same as the position with the lowest breakdown voltage. In addition, the intervention of floating electrode improved the spatial electric field and complexity of discharge physical process.

APA, Harvard, Vancouver, ISO, and other styles

9

Popov, A. V., A. V. Kazakov, D. V. Bukhtoyarov, and S. Yu Khatuntseva. "Experimental Studies of the Electrical Breakdown of Fire Extinguishing Powders." Occupational Safety in Industry, no. 2 (February 2021): 49–55. http://dx.doi.org/10.24000/0409-2961-2021-2-49-55.

Full text

Abstract:

The method for determining the breakdown voltage in the air suspension of fire extinguishing powder, simplified and more appropriate to the actual conditions of such powders use is proposed and tested. Experimental studies of the electrical breakdown of fire extinguishing powders in an alternating electrical field — homogeneous and non-homogeneous are presented. Double effect of fire extinguishing powders on the breakdown in a homogeneous electrical field in comparison with air is established. The first option: powders to a small extent complicate the breakdown (increase the breakdown voltage), which is due to the high electrical strength of solid dielectrics. The second option: powders slightly facilitate the breakdown. Presumably, this is due to the abnormally high polarizability of one of the components — monoammonium phosphate (ferroelectric). Due to the avalanche-like polarization caused by the ferroelectric, the uniformity of the field is disturbed, which reduces its electrical strength. In an inhomogeneous electric field, the breakdown voltage was about one third lower than in a homogeneous one, and exactly corresponds to the breakdown voltage of the air. In a homogeneous field between the electrodes the «bridges» of powder particles containing monoammonium phosphate appeared and continued to hang even after the breakdown. An unexpected phenomenon was revealed: a relatively weak dependence of the breakdown voltage on the presence of moisture in the extinguishing powder. It is advisable to continue research in this area. The main conclusion: fire extinguishing non-conductive powder does not participate in the electrical breakdown that goes through the air between the powder particles. In view of this, the voltage of 1 kV seems an anachronistic one, at which the use of powder fire extinguishers is allowed, while for carbon dioxide fire extinguishers this figure is 10 times higher (though the electrical strength of carbon dioxide is 0.9 of the air electrical strength). Since the air electrical strength depends on the external conditions (temperature, pressure, humidity, distance between the electrodes), it is proposed to enter relative values for the assessment of the extinguishing powder electrical strength, for example, the ratio of the breakdown voltage to the breakdown voltage in the air.

APA, Harvard, Vancouver, ISO, and other styles

10

Li, Li Li, Yu Long Wang, and Hong Da Yang. "Study on Relationships between High-Frequency High-Voltage Pulse Breakdown Voltage of Air-Gaps and Pulse Delay Time." Advanced Materials Research 981 (July 2014): 683–87. http://dx.doi.org/10.4028/www.scientific.net/amr.981.683.

Full text

Abstract:

In the paper, power frequency and high-frequency high-voltage pulse breakdown voltage of air-gaps were measured by circuits of spark gap switches respectively, and then output waveforms were obtained by sampling circuits, finally a large number of data in experiments were recorded and were drawn into curves. It can be seen from curves: firstly, relationships between pulse breakdown voltage of air-gaps and pulse delay time or between pulse breakdown voltage of air-gaps and pulse coefficient are discussed when electrodes and distances between electrodes are different, secondly, relationships between pulse breakdown voltage and air-gap distances are analyzed under 100kHz pulse voltage when electrodes are spherical electrodes.

APA, Harvard, Vancouver, ISO, and other styles

11

Han, Ki-Son, Jin-Yul Yoon, and Hyung-Jun Ju. "Breakdown Characteristics of Dry Air under 170[kV] GIB." Journal of the Korean Institute of Illuminating and Electrical Installation Engineers 24, no. 10 (October 31, 2010): 136–42. http://dx.doi.org/10.5207/jieie.2010.24.10.136.

Full text

APA, Harvard, Vancouver, ISO, and other styles

12

CAI, Xiyuan, Xiao ZHANG, Junyong LU, Sai TAN, Yongsheng ZHANG, and Guanxiang ZHANG. "Dielectric breakdown properties of Al-air mixtures." Plasma Science and Technology 23, no. 5 (April 13, 2021): 055401. http://dx.doi.org/10.1088/2058-6272/abe849.

Full text

APA, Harvard, Vancouver, ISO, and other styles

13

Wu, Hai Dong. "Experiment Research of Laser Induced Air Breakdown." Applied Mechanics and Materials 599-601 (August 2014): 201–4. http://dx.doi.org/10.4028/www.scientific.net/amm.599-601.201.

Full text

Abstract:

The principle of laser induced air breakdown was introduced. The laser energy conversion in ionization process was studied. The phenomenon of laser induced air breakdown was observed by using high speed camera. It was found that a higher laser energy induced more laser energy to transfer into light and sound energy. The plasma reached maximum in shape in about 20 to 30 ns after laser excitation, and disappeared in about 16μs.

APA, Harvard, Vancouver, ISO, and other styles

14

Herring, G. C., and S. Popović. "Microwave air breakdown enhanced with metallic initiators." Applied Physics Letters 92, no. 13 (March 31, 2008): 131501. http://dx.doi.org/10.1063/1.2897308.

Full text

APA, Harvard, Vancouver, ISO, and other styles

15

Li, H. F., Q. M. Zhang, and Z. W. Liu. "Holographic imaging of electrical breakdown in air." IEEE Transactions on Dielectrics and Electrical Insulation 18, no. 3 (June 2011): 819–21. http://dx.doi.org/10.1109/tdei.2011.5931070.

Full text

APA, Harvard, Vancouver, ISO, and other styles

16

Colonna, G., M. Capitelli, C. Grose, F. Paniccia, A. V. Eletskij, and B. M. Smirnov. "Breakdown conditions and thermal instability in air." Il Nuovo Cimento D 14, no. 6 (June 1992): 585–93. http://dx.doi.org/10.1007/bf02462345.

Full text

APA, Harvard, Vancouver, ISO, and other styles

17

Morrow, R., and JJ Lowke. "Electrical Breakdown in Air and in SF6." Australian Journal of Physics 48, no. 3 (1995): 453. http://dx.doi.org/10.1071/ph950453.

Full text

Abstract:

A theory is presented for the development of streamers from a positive point in atmospheric air. The continuity equations for electrons, positive ions, and negative ions are solved simultaneously with Poisson's equation. For an applied voltage of 20 kV across a 20 mm gap, streamers are predicted to cross the gap in 26 ns, and the calculated streamer velocities are in fair agreement with experiment. When the gap is increased to 50 mm for the same voltage, the streamer is predicted not to reach the cathode. In this case an intense electric field front rapidly propagates about 35 mm into the gap in 200 ns. For a further 9�5 �s the streamer slowly moves into the gap, until the electric field at the head of the streamer collapses, and the streamer front stops moving. Finally, only positive space-charge remains; this moves away from the point, allowing the field near the point to recover, giving rise to a secondary discharge near the anode. The electric field distribution is shown to be quite different from that found previously for SF6; this is explained by the much lower attachment coefficient in air compared with that in SF6. These results show that streamers in air have a far greater range than streamers in SF6. This greater range cannot be explained by comparison of the values of E*, the electric field at which ionisation equals attachment.

APA, Harvard, Vancouver, ISO, and other styles

18

Allen, N. L., M. Boutlendj, and H. A. Lightfoot. "Dielectric breakdown in nonuniform field air gaps." IEEE Transactions on Electrical Insulation 28, no. 2 (April 1993): 183–91. http://dx.doi.org/10.1109/14.212243.

Full text

APA, Harvard, Vancouver, ISO, and other styles

19

Watson, D. B., M. I. Barber, and K. A. Samuels. "Investigation of Electrical Breakdown in Air Using an Image Processing Technique." International Journal of Electrical Engineering & Education 29, no. 4 (October 1992): 313–20. http://dx.doi.org/10.1177/002072099202900406.

Full text

Abstract:

Investigation of electrical breakdown in air using an image processing technique Video recordings of high-voltage breakdown tracks between electrodes in air have been analysed using an image processing technique. The paper discusses the tortuosity of the breakdown tracks, and a logarithmic distribution of track segment lengths has been found.

APA, Harvard, Vancouver, ISO, and other styles

20

Zhang, Yu, Duan Yong Li, and Tao Wu. "Shadowgraph of Pulse CO₂ Laser Induced Breakdown in Different Pressure Air." Advanced Materials Research 887-888 (February 2014): 1001–4. http://dx.doi.org/10.4028/www.scientific.net/amr.887-888.1001.

Full text

Abstract:

The expansion property of an infrared CO2 laser produced air plasma is characterized using a high-speed imaging shadowgraph technique. The shadowgraphs were taken by a time-gated intensified charge-coupled device at various delay times after single pulses induced gas breakdown. We examined five incident laser energy of 180, 240, 345, 420 and 600 mJ induced air breakdown at the pressure of atmospheric and 104 Pa. A shock wave produced by laser induced breakdown was also observed and its speed was measured as a function delay time between the breakdown and the shadow imaging under different air pressure. The experimental results indicated that the radial and axial shock wave front evolutions showed similar behavior, which increased fast with delay time at early stage and slowly at later stage. The propagation speed of the wavefront was about 2 cm/μs at the initial stage of breakdown, and then decreased very quickly. The propagation speed under low air pressure was higher than that of gases under high pressure and the spark sustained less time at lower pressure. The size of laser induced air spark increased with incident laser energy but not simple linear relationships.

APA, Harvard, Vancouver, ISO, and other styles

21

Zhu, Xiao Bin, Tang Qin Wu, Lin He Zhang, and Hai Xiang Chen. "Experimental Study on the Breakdown of Gaps in Fire." Advanced Materials Research 354-355 (October 2011): 1201–4. http://dx.doi.org/10.4028/www.scientific.net/amr.354-355.1201.

Full text

Abstract:

Some flashover incidents of high-voltage transmission lines are reported to be induced by fire. Though the mechanism of fire induced flashover is not well understood, it is deemed that fire could reduce the insulation strength of air. This paper has compared the breakdown characteristics of gaps in normal air conditions and those in fire. The results show that the breakdown voltage or electric field strength of gaps in fire decreases greatly. The value of breakdown electric field strength in alcohol flame is about 1.454 KV/cm, which is only about 28.8% of that in air. The value of breakdown electric field strength in wood crib fire is about 0.300KV/cm, corresponding to 19.9% of that in air. This study demonstrates that flame and soot particle of fire are responsible for fire induce flashover of high-voltage transmission lines.

APA, Harvard, Vancouver, ISO, and other styles

22

Dong Liu, Dong Liu, Chuansong Chen Chuansong Chen, Baoyuan Man Baoyuan Man, Yanna Sun Yanna Sun, and and Feifei Li and Feifei Li. "Theoretical and experimental investigations on the threshold of a laser-induced breakdown of air." Chinese Optics Letters 14, no. 4 (2016): 040202–40206. http://dx.doi.org/10.3788/col201614.040202.

Full text

APA, Harvard, Vancouver, ISO, and other styles

23

Parigger, Christian G., Christopher M. Helstern, and Ghaneshwar Gautam. "Hypersonic Imaging and Emission Spectroscopy of Hydrogen and Cyanide Following Laser-Induced Optical Breakdown." Symmetry 12, no. 12 (December 19, 2020): 2116. http://dx.doi.org/10.3390/sym12122116.

Full text

Abstract:

This work communicates the connection of measured shadowgraphs from optically induced air breakdown with emission spectroscopy in selected gas mixtures. Laser-induced optical breakdown is generated using 850 and 170 mJ, 6 ns pulses at a wavelength of 1064 nm, the shadowgraphs are recorded using time-delayed 5 ns pulses at a wavelength of 532 nm and a digital camera, and emission spectra are recorded for typically a dozen of discrete time-delays from optical breakdown by employing an intensified charge-coupled device. The symmetry of the breakdown event can be viewed as close-to spherical symmetry for time-delays of several 100 ns. Spectroscopic analysis explores well-above hypersonic expansion dynamics using primarily the diatomic molecule cyanide and atomic hydrogen emission spectroscopy. Analysis of the air breakdown and selected gas breakdown events permits the use of Abel inversion for inference of the expanding species distribution. Typically, species are prevalent at higher density near the hypersonically expanding shockwave, measured by tracing cyanide and a specific carbon atomic line. Overall, recorded air breakdown shadowgraphs are indicative of laser-plasma expansion in selected gas mixtures, and optical spectroscopy delivers analytical insight into plasma expansion phenomena.

APA, Harvard, Vancouver, ISO, and other styles

24

Liu, Ting, Igor Timoshkin, Mark P. Wilson, Martin J. Given, and Scott J. MacGregor. "The Nanosecond Impulsive Breakdown Characteristics of Air, N2 and CO2 in a Sub-mm Gap." Plasma 5, no. 1 (December 30, 2021): 12–29. http://dx.doi.org/10.3390/plasma5010002.

Full text

Abstract:

The present paper investigates the breakdown characteristics—breakdown voltage, with breakdown occurring on the rising edge of the applied HV impulses, and time to breakdown—for gases of significance that are present in the atmosphere: air, N2 and CO2. These breakdown characteristics have been obtained in a 100 µm gap between an HV needle and plane ground electrode, when stressed with sub-µs impulses of both polarities, with a rise time up to ~50 ns. The scaling relationships between the reduced breakdown field Etip/N and the product of the gas number density and inter-electrode gap, Nd, were obtained for all tested gases over a wide range of Nd values, from ~1020 m−2 to ~1025 m−2. The breakdown field-time to breakdown characteristics obtained at different gas pressures are presented as scaling relationships of Etip/N, Nd, and Ntbr for each gas, and compared with data from the literature.

APA, Harvard, Vancouver, ISO, and other styles

25

Zhou Qian-Hong, Sun Hui-Fang, Dong Zhi-Wei, and Zhou Hai-Jing. "Theoretical study on the microwave air breakdown threshold." Acta Physica Sinica 64, no. 17 (2015): 175202. http://dx.doi.org/10.7498/aps.64.175202.

Full text

APA, Harvard, Vancouver, ISO, and other styles

26

Song, Jae-Woo, Se-Woo Jang, Ihn-Seok Ahn, and Jun-Oh Jang. "Breakdown Characteristics of Rod-Electrodes using Imitation Air." Journal of the Korean Institute of Illuminating and Electrical Installation Engineers 27, no. 8 (August 31, 2013): 16–20. http://dx.doi.org/10.5207/jieie.2013.27.8.016.

Full text

APA, Harvard, Vancouver, ISO, and other styles

27

Aleksandrov, A. F., V. L. Bychkov, and S. A. Volkov. "Breakdown characteristics of air in the lower atmosphere." Moscow University Physics Bulletin 66, no. 1 (February 2011): 88–91. http://dx.doi.org/10.3103/s0027134911010048.

Full text

APA, Harvard, Vancouver, ISO, and other styles

28

Guo-zhi, Liu, Liu Jing-yue, Huang Wen-hua, Zhou Jin-shan, Song Xiao-xin, and Ning Hui. "A study of high power microwave air breakdown." Chinese Physics 9, no. 10 (October 2000): 757–63. http://dx.doi.org/10.1088/1009-1963/9/10/008.

Full text

APA, Harvard, Vancouver, ISO, and other styles

29

Hu, Z., and H. von Seggern. "Air-breakdown charging mechanism of fibrous polytetrafluoroethylene films." Journal of Applied Physics 98, no. 1 (July 2005): 014108. http://dx.doi.org/10.1063/1.1939067.

Full text

APA, Harvard, Vancouver, ISO, and other styles

30

Barashenkov, V. S., L. P. Grachev, I. I. Esakov, B. F. Kostenko, K. V. Khodataev, and M. Z. Yur’ev. "Breakdown in air in a rising microwave field." Technical Physics 45, no. 10 (October 2000): 1265–70. http://dx.doi.org/10.1134/1.1318961.

Full text

APA, Harvard, Vancouver, ISO, and other styles

31

Gurevich, A. V., G. A. Mesyats, K. P. Zybin, A. G. Reutova, V. G. Shpak, S. A. Shunailov, and M. I. Yalandin. "Laboratory demonstration of runaway electron breakdown of air." Physics Letters A 375, no. 30-31 (July 2011): 2845–49. http://dx.doi.org/10.1016/j.physleta.2011.06.004.

Full text

APA, Harvard, Vancouver, ISO, and other styles

32

Zhao, Pengcheng, Ju Feng, and Cheng Liao. "Breakdown in Air Produced by High Power Microwaves." IEEE Transactions on Plasma Science 42, no. 6 (June 2014): 1560–66. http://dx.doi.org/10.1109/tps.2014.2317492.

Full text

APA, Harvard, Vancouver, ISO, and other styles

33

Luo, Jianjun, Liang Xu, Wei Tang, Tao Jiang, Feng Ru Fan, Yaokun Pang, Libo Chen, Yan Zhang, and Zhong Lin Wang. "Direct-Current Triboelectric Nanogenerator Realized by Air Breakdown Induced Ionized Air Channel." Advanced Energy Materials 8, no. 27 (August 16, 2018): 1800889. http://dx.doi.org/10.1002/aenm.201800889.

Full text

APA, Harvard, Vancouver, ISO, and other styles

34

Yao, Xiuyuan, Bingxue Yang, Jianghai Geng, Yu Su, Hua Yu, Guohua Yang, and Xinwei Wang. "Intelligent computing and analysis of breakdown voltage of rod-rod long air gap." Journal of Physics: Conference Series 2215, no. 1 (February 1, 2022): 012011. http://dx.doi.org/10.1088/1742-6596/2215/1/012011.

Full text

Abstract:

Abstract The discharge characteristics of air gap is one of the important factors to determine the insulation level which is crucial for electrical engineering construction. In order to calculate the 50% breakdown voltage of rod-rod air gap under different meteorological conditions and different gap distances, we take the positive standard switching impulse test data of rod-rod air gap under different meteorological conditions as samples. Based on training set, a breakdown voltage prediction model of rod-rod air gap under different meteorological conditions was established by cuckoo search optimized weighted support vector regression (CS-ω-SVR). The results show that the average absolute percentage error of the test set is 3.6%, which verifies the validity of this computing method. The method can provide reference for the computation of air gap breakdown voltage under different altitudes and extreme meteorological conditions.

APA, Harvard, Vancouver, ISO, and other styles

35

El-Masri, M. A. "Exergy Analysis of Combined Cycles: Part 1—Air-Cooled Brayton-Cycle Gas Turbines." Journal of Engineering for Gas Turbines and Power 109, no. 2 (April 1, 1987): 228–36. http://dx.doi.org/10.1115/1.3240029.

Full text

Abstract:

Quantitative analytical tools based on the second law of thermodynamics provide insight into the complex optimization tradeoffs encountered in the design of a combined cycle. These tools are especially valuable when considering approaches beyond the existing body of experience, whether in cycle configuration or in gas turbine cooling technology. A framework for such analysis was provided by the author [1-3] using simplified, constant-property models. In this paper, this theme is developed to include actual chemical and thermodynamic properties as well as relevant practical design details reflecting current engineering practice. The second-law model is applied to calculate and provide a detailed breakdown of the sources of inefficiency of a combined cycle. Stage-by-stage turbine cooling flow and loss analysis calculations are performed using the GASCAN program and examples of the resulting loss breakdowns presented. It is shown that the dominant interaction governing the variation of cycle efficiency with turbine inlet temperature is that between combustion irreversibility and turbine cooling losses. Compressor and pressure-drop losses are shown to be relatively small. A detailed analysis and loss breakdown of the steam bottoming cycle is presented in Part 2 of this paper.

APA, Harvard, Vancouver, ISO, and other styles

36

Hu, Zhengyong, Peng Xu, Wenlong Tan, Kai Gao, and Lv Cui. "Breakdown Characteristics of Long Air Gap at Different Frequency Based on Series Resonance." Journal of Physics: Conference Series 2143, no. 1 (December 1, 2021): 012051. http://dx.doi.org/10.1088/1742-6596/2143/1/012051.

Full text

Abstract:

Abstract In today’s rapid economic development, with the development of science and technology, higher requirements have been put forward in the economic operation of the system. This requires various departments to make more reasonable use of existing energy and equipment, and to ensure quality. Meet all aspects of supply with more energy-saving and more economical operation methods. Therefore, more and more attention has been paid to the research on the method of predicting the breakdown voltage of the air gap. Although domestic and foreign scholars have used power frequency test transformers to carry out a large number of long air gap experimental researches, the research on the breakdown voltage of long air gaps based on the principle of vector machines is still blank. In this paper, a vector machine test device is used to study the breakdown discharge characteristics of a long air gap at two frequencies of 229Hz and 68Hz. Comparing the test phenomena at different frequencies, it is found that the initial discharge voltage of the streamer corona is lower when the frequency is 229Hz, and the discharge phenomenon before breakdown is more intense, and the quality factor will be significantly reduced due to the violent discharge. At the same time, under the same test conditions, the breakdown voltage at 229Hz is lower than that at 68Hz, and as the air gap increases, the difference between the two is greater. The experimental results show that the breakdown voltage of the long air gap based on the vector machine is different when the frequency is different, and the safety distance of the field withstand voltage test should be evaluated according to the experimental data under the vector machine condition to ensure the safety of the test.

APA, Harvard, Vancouver, ISO, and other styles

37

Settaouti, Abderrahmane. "Impulse Breakdown Characteristics of Main Gap in the Presence of a Local Discharge." Journal of Applied Science & Process Engineering 6, no. 2 (October 1, 2019): 413–23. http://dx.doi.org/10.33736/jaspe.983.2019.

Full text

Abstract:

The characteristics of impulse breakdown voltages and the influence of the position of third electrode in air gap are investigated experimentally to study the parameters influencing the breakdown voltage in the presence of metallic objects around the high voltage power apparatus with air insulation. Experimental results show that the factors affecting the breakdown voltage are the shape and the size of the grounded electrode, the third metallic electrode location and the gap length. A comparison between negative and positive polarities of the applied voltages indicates an important influence of the polarity in the dielectric breakdown mechanism. The possible mechanism by which the local electric discharge initiates the main dielectric breakdown seems to be the high electric field around the local discharge channel and the streamers protruding from its surface.

APA, Harvard, Vancouver, ISO, and other styles

38

Ilyin, Alexey, Ivan Nagorny, and Yulia Biryukova. "Optical Breakdown on the Inclined Target: The Features of the Erosive Plume Formation." Applied Mechanics and Materials 723 (January 2015): 825–28. http://dx.doi.org/10.4028/www.scientific.net/amm.723.825.

Full text

Abstract:

For oblique incidence of laser radiation on the target, the breakdown of air and erosive jet are separated in time and space. The electron density is higher in the air breakdown area while Al I density is higher in an erosive plume area. We also defined plasma expansion mechanism and estimate the time of erosive plume formation.

APA, Harvard, Vancouver, ISO, and other styles

39

Yi Wang, Chien, and Paul C. Wang. "Nondestructive Detection of Core Breakdown in ‘Bartlett’ Pears with Nuclear Magnetic Resonance Imaging." HortScience 24, no. 1 (February 1989): 106–9. http://dx.doi.org/10.21273/hortsci.24.1.106.

Full text

Abstract:

Abstract The development of core breakdown in ‘Bartlett’ pears (Pyrus communis L.) held at 20°C after 3 months of storage in air or in 1% O2 at 0° was monitored with nuclear magnetic resonance (NMR) imaging. Longitudinal NMR images of the fruit revealed the presence and severity of core breakdown. The progress of the disorder inside the fruit could be clearly seen without destroying the fruit. A distinct difference in the degree of core breakdown between air and low-O2 stored fruit could be discerned in the NMR images.

APA, Harvard, Vancouver, ISO, and other styles

40

Weis, Sarah A., William J. Bramlage, and Mack Drake. "Comparison of Four Sampling Methods for Predicting Poststorage Senescent Breakdown of ‘McIntosh’ Apple Fruit from Preharvest Mineral Composition." Journal of the American Society for Horticultural Science 110, no. 5 (September 1985): 710–14. http://dx.doi.org/10.21273/jashs.110.5.710.

Full text

Abstract:

Abstract A 4-year study compared 4 methods of subsampling ‘McIntosh’ apples for mineral analyses intended for use in predicting postharvest senescent breakdown. Concentrations of Ca, Mg, K, P, and N were determined in outer cortex, whole fruit, and juice in 1979 and 1980, and in outer cortex and cortical plugs in 1981 and 1982. Multiple linear regression equations were developed for each sampling in 1979 and 1981 relating the natural logarithms (In) of Ca and P concentrations and Mg:Ca, K:Ca, and N:Ca ratios to In (breakdown percentage +1). Effectiveness of each equation as a predictor of breakdown during and following storage was tested using data collected the following year. Paired t tests comparing predicted breakdown, using 1979 equations and 1980 mineral analyses, to breakdown observed after storage in 1980-1981 showed that outer cortex- and whole fruit-based predictions were not significantly different from observed breakdown, but juice equations predicted significantly more breakdown than was observed. Correlation coefficients relating actual to predicted breakdown were positive and significant for all 3 methods. In 1981, separate equations were developed to predict fruit breakdown after air and after controlled atmosphere (CA) storage. Paired t tests showed the predicted incidence of breakdown following CA storage was not significantly different from actual breakdown incidences for either outer cortex or cortical plug equations. Breakdown incidence following air storage was less than predicted. In all instances, correlation between actual and predicted breakdown incidence was positive and significant. Outer cortex, whole fruit, and cortical plug analyses showed promise as breakdown predictors, but juice analyses were ineffective.

APA, Harvard, Vancouver, ISO, and other styles

41

Widyastuti, Christine, Tasdik Darmana, and Oktaria Handayani. "PENGARUH KADAR AIR TERHADAP TEGANGAN TEMBUS MINYAK TRANSFORMATOR DISTRIBUSI." Energi & Kelistrikan 10, no. 2 (January 28, 2019): 129–36. http://dx.doi.org/10.33322/energi.v10i2.232.

Full text

Abstract:

Abstract Transformer oil is one of the liquid insulating materials that functions as insulation and cooling in the transformer. Some oil insulation materials must have the ability to withstand penetrating stresses, while as a transformer oil cooler must be able to reduce the heat generated, so that with these two capabilities transformer oil is expected to be able to protect the transformer from interference. Examination of breakdown stress using the IEC 60156-1995 method. For evaluation of oil on the power transformer determines the water content. The feasibility of transformer oil uses breakdown voltage and water content testing as a result of feasibility simulations based on international standards to improve reliability in the treatment of power transformers in the industrial world especially for community service. With greater breakdown voltage, it proves that the oil is still suitable for use. Whereas if the oil water content is higher, it proves that the oil is not suitable for use. Transformer oil, according to the PLN (SPLN) test standards 49-1 / 1992, must have a 30kV / 2.5mm breakdown voltage. In the study of sample A and sample B it has a breakdown voltage of 14kVA and 18kVA. With this, sample A and sample B are not suitable for use. Keywords: moisture content, transformer oil, breakdown voltage, SPLN 49-1 / 1992 ABSTRAK Minyak transformator merupakan salah satu bahan isolasi cair yang berfungsi sebagai isolasi dan pendingin pada transformator. Sebagian bahan isolasi minyak harus memiliki kemampuan untuk menahan tegangan tembus, sedangkan sebagai pendingin minyak transformator harus mampu meredam panas yang ditimbulkan, sehingga dengan kedua kemampuan ini maka minyak transformator diharapkan mampu melindungi transformator dari gangguan. Pengujian tegangan tembus menggunakan metode IEC 60156-1995. Untuk evaluasi minyak pada transformator daya menentukan kadar air. Kelayakan minyak transformator menggunakan pengujian tegangan tembus dan kadar air sebagai hasil simulasi kelayakan berdasarkan standar internasional untuk meningkatkan kehandalan dalam perawatan transformator daya dalam dunia industri khususnya terhadap pelayanan masyarakat. Dengan tegangan tembus yang semakin besar membuktikan minyak tersebut masih layak pakai. Sedangkan apabila kadar air minyak tersebut semakin tinggi membuktikan minyak tersebut sudah tidak layak pakai. Minyak transformator, sesuai standar uji PLN (SPLN) 49-1/1992 harus memiliki tegangan tembus 30kV/2,5mm. Dalam penelitian dari sampel A dan sampel B memiliki tegangan tembus sebesar 14kVA dan 18kVA. Dengan ini, sampel A dan sampel B tidak layak pakai. Kata kunci: kadar air, minyak trafo, tegangan tembus, SPLN 49-1/1992

APA, Harvard, Vancouver, ISO, and other styles

42

Gao, Jiachen, Linong Wang, Qiushi Zhang, and Bin Song. "Modeling of Positive Switching Impulse Discharge of UHV Transmission Line Air Gaps." Applied Sciences 8, no. 12 (December 12, 2018): 2594. http://dx.doi.org/10.3390/app8122594.

Full text

Abstract:

Positive switching impulse discharge characteristics are an important basis for the external insulation design of transmission line towers. At present, the characteristics are obtained mainly by real tower discharge tests. Since the existing research on the discharge model is not perfect, test designs are not reasonable, which results in high costs. The influence of line height and tower width on the discharge characteristics of Ultra High Voltage (UHV) transmission lines air gaps is studied in this paper. The results show that the line height had little influence on the breakdown voltage of air gaps in UHV transmission lines. A tower-width discharge model was obtained by fitting the breakdown voltage of air gaps with different gap lengths and tower widths. By analyzing the gap characteristic factors of different transmission lines, a discharge model of different tower air gaps in UHV transmission lines was presented. The breakdown voltage calculated by the models was in good agreement with the test results, and the errors were not more than 5%.

APA, Harvard, Vancouver, ISO, and other styles

43

Vazhov V. F., Petrenko E. V., and Yudin A. S. "Electric strength of dielectrics under influence of bipolar voltage pulses of submicrosecond duration." Technical Physics 92, no. 4 (2022): 537. http://dx.doi.org/10.21883/tp.2022.04.53613.304-21.

Full text

Abstract:

The development of electric pulse technologies for the destruction of solids states (rocks) --- drilling, cutting and crushing requires reduction of high pulse voltages. In this work, for the first time, studies are proposed and carried out to determine the breakdown voltages of various dielectric media (air, water, rocks) while simultaneously supplying two pulses to the electrode system by two high voltage generators of different polarity --- positive and negative, which halves the operating impulse voltage each generator. In addition, experiments have shown that for all media there is a decrease in breakdown voltage in comparison with a monopolar voltage pulse, which reaches 28% --- for the breakdown of sandstone, 23% --- granite, 24% --- water, 25% --- air. A physical explanation of the discovered effect is given. Keywords: monopolar and bipolar pulse voltage, breakdown voltage, discharge channel.

APA, Harvard, Vancouver, ISO, and other styles

44

Tran, Michael, Benjamin W. Smith, David W. Hahn, and James D. Winefordner. "Detection of Gaseous and Particulate Fluorides by Laser-Induced Breakdown Spectroscopy." Applied Spectroscopy 55, no. 11 (November 2001): 1455–61. http://dx.doi.org/10.1366/0003702011953865.

Full text

Abstract:

Laser-induced breakdown spectroscopy (LIBS) was evaluated for the detection of gaseous and particulate fluorides in air and other gas mixtures. Analytical figures of merit were compared in pure air, pure He, air-He mixtures, and air with a He sheath flow. Particulate samples were also collected on filters and subsequently detected. It was demonstrated that SF6 is a suitable surrogate for calibration and optimization for the detection of HF in air. For gaseous F in air, limits of detection obtained were 40 mg/m3 for the direct measurement in air and 5 mg/m3 when the air sample was sheathed in He. For particulate F in air, limits of detection were 9 mg/m3 for direct measurement in air and 0.5 mg/m3 using He sheath flow. When the particulates were preconcentrated by collection on a filter and subsequently analyzed, the limit of detection for F was improved to 5 μg/m3 for a 10-min sampling time at 10 L/min flow rate using subsequent LIBS measurements in pure He.

APA, Harvard, Vancouver, ISO, and other styles

45

Wu, Xiaohan, Bin Cao, Zong Li, Daiming Yang, Shuhang Shen, and Liming Wang. "DC Breakdown Characteristic of Air Gap With Water Droplets." IEEE Transactions on Plasma Science 49, no. 6 (June 2021): 1962–68. http://dx.doi.org/10.1109/tps.2021.3079137.

Full text

APA, Harvard, Vancouver, ISO, and other styles

46

Han, Ki-Son, Hyung-Jun Ju, Jin-Yul Yoon, and Hong-Geun You. "Breakdown Characteristics of Dry Air under 362 kV GIB." Journal of the Korean Institute of Electrical and Electronic Material Engineers 23, no. 10 (October 1, 2010): 804–8. http://dx.doi.org/10.4313/jkem.2010.23.10.804.

Full text

APA, Harvard, Vancouver, ISO, and other styles

47

Lim, Chang-Ho, Eun-Hyeok Choi, Do-Seok Kim, Young-Su Kim, Won-Zoo Park, and Kwang-Sik Lee. "Breakdown characteristics of SF6and Imitation Air in Temperature Decline." Journal of the Korean Institute of Illuminating and Electrical Installation Engineers 21, no. 4 (May 31, 2007): 115–21. http://dx.doi.org/10.5207/jieie.2007.21.4.115.

Full text

APA, Harvard, Vancouver, ISO, and other styles

48

Bright, Alfram, Nathan Tichenor, Kevin Kremeyer, and Richard Wlezien. "Boundary-Layer Separation Control Using Laser-Induced Air Breakdown." AIAA Journal 56, no. 4 (April 2018): 1472–82. http://dx.doi.org/10.2514/1.j055272.

Full text

APA, Harvard, Vancouver, ISO, and other styles

49

Doty, Steven D., and Sandra L. Doty. "Dielectric breakdown of air as order-of-magnitude physics." Physics Teacher 36, no. 1 (January 1998): 6–9. http://dx.doi.org/10.1119/1.879973.

Full text

APA, Harvard, Vancouver, ISO, and other styles

50

Zhao, Pengcheng, Lixin Guo, and Panpan Shu. "Effect of air breakdown on microwave pulse energy transmission." Chinese Physics B 26, no. 2 (February 2017): 029201. http://dx.doi.org/10.1088/1674-1056/26/2/029201.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Air Breakdown'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles