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Journal articles on the topic 'Leader discharge'

Author: Grafiati

Published: 6 September 2023

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1

Rakov, V. A., M. D. Tran, Y. Zhu, Z. Ding, A. F. R. Leal, I. Kereszy, and S. Chen. "New insights into the lightning discharge processes." Plasma Sources Science and Technology 31, no. 10 (October 1, 2022): 104005. http://dx.doi.org/10.1088/1361-6595/ac9330.

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Abstract This review covers selected results of recent observations of lightning discharges performed across the entire electromagnetic spectrum (radiofrequency, optical, and energetic radiation) at the Lightning Observatory in Gainesville, Florida. The most important results include (a) characterization of the preliminary-breakdown, stepped-leader, and return-stroke processes in high-intensity (⩾50 kA) negative lightning discharges, (b) the first high-speed video images of bidirectional leader that made contact with the ground and produced a return stroke, (c) discovery of negative stepped leader branches colliding with the lateral surface of neighboring branches of the same leader, (d) new data on the occurrence context and properties of compact intracloud discharges, and (e) observation of a terrestrial gamma-ray flash that occurred during a bipolar cloud-to-ground lightning discharge. The results serve to improve our understanding of the physics of lightning with important implications for lightning modeling, lightning protection, and high-energy atmospheric physics studies.

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2

Das, Sayantan, and Udaya Kumar. "Modeling of Bi-Polar Leader Inception and Propagation from Flying Aircraft Prior to a Lightning Strike." Atmosphere 13, no. 6 (June 9, 2022): 943. http://dx.doi.org/10.3390/atmos13060943.

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Lightning is one of the major environmental threats to aircraft. The lightning strikes during flying are mostly attributed to aircraft-triggered lightning. The first step toward designing suitable protective measures against lightning is identifying the attachment locations. For this purpose, oversimplified approaches are currently employed, which do not represent the associated discharge phenomena. Therefore, in this work, a suitable model is developed for simulating the inception and propagation of bi-polar leader discharge from the aircraft. Modeling of leader discharges requires field computation around the aircraft, which is carried out employing the Surface Charge Simulation Method (SCSM) combined with sub-modeling, which ensures the best accuracy of field computations near nosecone, wingtips, etc. A DC10 aircraft model is considered for the simulation. Simulations are performed for different pairs of leader inception points on aircraft using the developed model. Subsequently, corresponding ambient fields required for stable bi-polar discharge from aircraft are determined. These values are in the range of measured ambient fields reported in the literature. In summary, the present work has come up with a suitable model for simulating the bi-polar leader inception and propagation from the flying aircraft. Using the same, a detailed quantitative description of the discharge phenomena from the aircraft is provided.

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3

Ma, Xinyu, Chijie Zhuang, Zezhong Wang, and Rong Zeng. "Positive Leader Velocity and Discharge Current Considering Leader Branching Under Different Air Pressures." IEEE Transactions on Plasma Science 47, no. 5 (May 2019): 1939–43. http://dx.doi.org/10.1109/tps.2018.2886570.

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4

Belosheev, V. P. "Discharge leader self-organization on the water surface." Technical Physics 45, no. 7 (July 2000): 922–27. http://dx.doi.org/10.1134/1.1259749.

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5

Xie, Yaoheng, Yue Yishi, Huisheng Ye, Liu Yun, Yongheng Zhong, and Xiangeng Zhao. "The development characteristics of the discontinuous leader under the positive switching impulse with low rate of voltage rising." European Physical Journal Applied Physics 83, no. 2 (August 2018): 20802. http://dx.doi.org/10.1051/epjap/2018180103.

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Discontinuous leader development is the most important discharge process under the application of the switching impulse voltage with the low rate of voltage rising, which is of great significance to study the external insulation characteristics of ultra-high voltage (UHV) large scale air gap. Based on the CMOS high-speed camera, a discharge test with different operating impulse voltage is carried out by constructing a comprehensive observation platform of rod-plate air gap discharge, and a clear discontinuous leader development process picture is captured. Moreover, the leader current, injection charge and leader channel unit length charge, and their characteristics of the change trend are also obtained. Further analysis based on the experimental results shows that the discontinuous leader development under the action of the impulse voltage with low rate of voltage rising has two different laws. Finally, this paper uses the thermodynamic equation, combined with the test results, the channel temperature changes in the discontinuous leader development stagnation stage were calculated. The results show that the leader channel temperature is still greater than 1500 K in the hundreds of microsecond time scales in the leader stagnation stage, and the subsequent leader can continue to develop on the original leader channel.

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6

Qie, X., Y. Yu, C. Guo, P. Laroche, G. Zhang, and Q. Zhang. "Some features of stepped and dart-stepped leaders near the ground in natural negative cloud-to-ground lightning discharges." Annales Geophysicae 20, no. 6 (June 30, 2002): 863–70. http://dx.doi.org/10.5194/angeo-20-863-2002.

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Abstract. Characteristics of the electric fields produced by stepped and dart-stepped leaders 200 µs just prior to the return strokes during natural negative cloud-to-ground (CG) lightning discharges have been analyzed by using data from a broad-band slow antenna system with 0.08 µs time resolution in southeastern China. It has been found that the electric field changes between the last stepped leader and the first return stroke could be classified in three categories. The first type is characterized by a small pulse superimposed on the abrupt beginning of the return stroke, and accounts for 42% of all the cases. The second type accounts for 33.3% and is characterized by relatively smooth electric field changes between the last leader pulse and the following return stroke. The third type accounts for 24.7%, and is characterized by small pulses between the last recognizable leader pulse and the following return stroke. On the average, the time interval between the successive leader pulses prior to the first return strokes and subsequent return strokes was 15.8 µs and 9.4 µs, respectively. The distribution of time intervals between successive stepped leader pulses is quite similar to Gaussian distribution while that for dart-stepped leader pulses is more similar to a log-normal distribution. Other discharge features, such as the average time interval between the last leader step and the first return stroke peak, the ratio of the last leader pulse peak to that of the return stroke amplitude are also discussed in the paper.Key words. Meteology and atmospheric dynamics (atmospheric electricity; lightning) – Radio science (electromagnetic noise and interference)

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7

Cooray, Vernon, Hasupama Jayasinghe, Marcos Rubinstein, and Farhad Rachidi. "The Geometry and Charge of the Streamer Bursts Generated by Lightning Rods under the Influence of High Electric Fields." Atmosphere 13, no. 12 (December 2, 2022): 2028. http://dx.doi.org/10.3390/atmos13122028.

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The streamer bursts generated during the initiation and propagation of leaders play an important role in the creation and maintenance of hot discharge channels in air. The most important parameters related to streamer bursts in this respect are the length of the streamer bursts, their lateral extent and the charge associated with them. The lateral extent of the streamer bursts may play a significant role in deciding the path and the tortuosity of the discharge channels of laboratory discharges and lightning. The charges associated with the streamer bursts are needed in understanding the physical processes associated with the streamer-to-leader transition. In this paper, the length, the lateral extension and the charge of the streamer regions generated by grounded conductors when exposed to external electric fields are estimated. This estimation is based on two assumptions: (i) once a streamer is incepted, the streamer head follows the direction of maximum background electric field at the location of the streamer head and (ii) the streamer continues to extend along this direction until the potential drop along the streamer channel matches the potential drop caused by the background electric field between the initial and end points of the streamer channel. The same technique could be used to estimate the streamer bursts generated in laboratory discharges and lightning stepped leaders. It is shown that in estimating the geometry of the streamer region, it is necessary to include the spread of streamers caused by branching. Moreover, the charge associated with the streamer region increases as the frequency of branching increases. The results obtained confirm that the charge in the streamer region can significantly change the potential ahead of the streamer region from the background potential and this has to be taken into account in any study that simulates the initiation and propagation of lightning leaders. Since the streamer bursts of leaders control the direction and speed of the leaders, the technique we have used here could be implemented in lightning leader progression models.

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8

Keffer, C. W. "Waste Discharge Reduction Program Overview – Monsanto Agricultural Company." Water Science and Technology 24, no. 12 (December 1, 1991): 29–32. http://dx.doi.org/10.2166/wst.1991.0367.

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Monsanto is committed to being a leader in reducing waste discharges to the environment. The Company announced in June 1988 a commitment to reduce air emissions of hazardous materials by 90% by the end of 1992. In addition, Monsanto Agricultural Company established a further goal to reduce the discharge of organic and hazardous inorganic materials to all environmental media. Projects have been identified for the Agricultural Company to achieve the 90% air emission reduction goal and to reduce projected 1995 waste discharges from 150 million pounds to 50 million pounds.

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9

Pei, Zhehao, Weijiang Chen, Xing Fan, Jianwei Gu, Shengxin Huang, Xiaosong Liu, Zhong Fu, et al. "The contribution of femtosecond laser filaments to positive and negative breakdown discharge in a long air gap." Physics of Plasmas 30, no. 4 (April 2023): 043511. http://dx.doi.org/10.1063/5.0138646.

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Discharges of different polarities develop in different modes, resulting in different guiding effects by femtosecond laser filaments. Knowledge of the contribution of laser filaments to positive and negative discharges is the basis of the laser-guided long-air-gap discharge technique. This study presents a direct comparison of the inception, propagation, and breakdown characteristics of discharges of both polarities. Long-air-gap discharge experiments under the switching impulses of both polarities are carried out under the same experimental conditions. Discharge modes and phases are also considered. The statistical results show that positive discharge inception voltages are transformed from a Weibull distribution into an exponential distribution under the influence of laser filaments, but there is little effect on the negative discharge inception voltage. The guidance probability of a positive discharge reaches 15% at most during the dark period stage, leading to little effect on the breakdown discharge probability. However, for negative discharges, the guidance probability can exceed 95%. An investigation of the filament contributions to both polarity discharges shows that the different migration directions of photoelectrons lead to a difference in the effects of laser filaments on inception voltages, and the difference in the connection of the two discharge passages leads to a difference in the guidance probability. Through the results of a simulation model, it is speculated that the connection condition for positive discharges is that the positive leader overlaps with the laser filaments, and, for negative discharges, the rod electrode is connected to the laser filaments through bi-directional discharge propagation.

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10

Molas, Michał, and Marcin Szewczyk. "Experimental Evaluation of 3D Tortuosity of Long Laboratory Spark Trajectory for Sphere-Sphere and Sphere-Plane Discharges under Lightning and Switching Impulse Voltages." Energies 14, no. 21 (November 7, 2021): 7409. http://dx.doi.org/10.3390/en14217409.

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Evaluation of attractive areas of high- and ultra-high voltage power transmission lines to direct lightning strokes is based on modeling of propagating progress of the lightning leader approaching the transmission line. The aim of the modeling is to determine the effectiveness of lightning protection for a given line design. The statistical models are currently being developed to extend the conventional deterministic models by embracing the randomness of the discharge channel in space and hence to reproduce the statistical distribution of the striking points. These models require experimental data for understanding of the lightning leader development process and to validate the model across the measurement data. This paper reports on the measured trajectories of discharge channels of long laboratory sparks in various high voltage laboratory arrangements. The sparks were initiated by switching and lightning impulses with peak values ranging from 1200 kV to 3364 kV of positive and negative polarity for two types of high-voltage electrode systems (sphere-sphere and sphere-plane), arranged at distances of 3.3 m and 5.5 m from each other. Statistical distributions of angles describing trajectory of discharge channels in space are reported for a total number of 540 recorded discharges. The results can serve as reference measurement data to develop and evaluate the accuracy of simulation models incorporating statistical nature of the lightning leader development process.

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11

Cui, Yingzhe, Chijie Zhuang, Rong Zeng, and Xuan Zhou. "Shock wave in a long-air-gap leader discharge." AIP Advances 9, no. 6 (June 2019): 065011. http://dx.doi.org/10.1063/1.5100519.

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12

Bogatov N. A., Syssoev V.S., Sukharevsky D. I., and Naumova M. Yu. "Microwave diagnostics of electrical discharges in an artificial cloud of charged water drops." Technical Physics 92, no. 3 (2022): 306. http://dx.doi.org/10.21883/tp.2022.03.53260.284-21.

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The microwave diagnostics of discharges occurring in an artificial cloud of charged water droplets created in an open air simulating the environment of thunderclouds is implemented. An artificial cloud with a droplet size of about 1 microns is opaque in the visible range, so intra-cloud discharges are not available for investigation by traditional methods in the spark discharge physics based on the registration of visible discharge radiation. Microwaves pass through such a cloud without noticeable attenuation, they interact only with the plasma of discharges occurring in the cloud. The probing microwave radiation had a wavelength of 8 mm. The attenuation of microwaves passed through the cloud was measured with temporary resolution of about 10 ns. The temporal characteristics of intra-cloud discharges were investigated. Keywords: spark, leader, streamer, electromagnetic wave.

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13

Setia, Nina, and Christine Meade. "Bundling the Value of Discharge Telephone Calls and Leader Rounding." JONA: The Journal of Nursing Administration 39, no. 3 (March 2009): 138–41. http://dx.doi.org/10.1097/nna.0b013e31819894f1.

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14

Lehtinen, Nikolai G., and Robert Marskar. "What Determines the Parameters of a Propagating Streamer: A Comparison of Outputs of the Streamer Parameter Model and of Hydrodynamic Simulations." Atmosphere 12, no. 12 (December 11, 2021): 1664. http://dx.doi.org/10.3390/atmos12121664.

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Electric streamer discharges (streamers) in the air are a very important stage of lightning, taking place before formation of the leader discharge, and with which an electric discharge starts from conducting objects which enhance the background electric field, such as airplanes. Despite years of research, it is still not well understood what mechanism determines the values of a streamer’s parameters, such as its radius and propagation velocity. The novel Streamer Parameter Model (SPM) was made to explain this mechanism, and to provide a way to efficiently calculate streamer parameters. Previously, we demonstrated that SPM results compared well with a limited set of experimental data. In this article, we compare SPM predictions to the published hydrodynamic simulation (HDS) results.

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15

Du, Tang, Li, Zou, Ma, Sun, Liu, and Zeng. "Thermal Characteristics of Positive Leaders under Different Electrode Terminals in a Long Air Gap." Energies 12, no. 21 (October 23, 2019): 4024. http://dx.doi.org/10.3390/en12214024.

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The thermal characteristics of the positive leader discharges occurring under the different electrode terminals in a 1 m rod-plate air gap were studied quantitatively using Mach–Zehnder interferometry and a high-speed video camera. When disturbed by the discharge channel, the interference fringes are distorted because of the change in the refractive index of air, which is related to the gas density. Therefore, the gas temperature and gas density distribution in the leader channel can be retrieved from the offset of the interference fringes. Based on these results, the thermal characteristics of the leader channel were studied under different electrode terminals with a radius of curvature of 2.5 mm and 5 mm for cone electrodes and a diameter of 40 mm for a spherical electrode. The results show that the gas temperature in the leader channel increased while the gas density decreased as the radius of curvature of the electrode terminal decreased. Additionally, a smaller radius of curvature leads to a larger thermal diameter, but the difference in the thermal diameter is not obvious; for the terminals used in this paper, the difference is within 2 mm.

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16

Deng, Junbo, Haibao Mu, Guanjun Zhang, Shigeyasu Matsuoka, Akiko Kumada, and Kunihiko Hidaka. "Residual Charge Distribution of Surface Leader Discharge Under Positive Impulse Voltage." IEEE Transactions on Plasma Science 41, no. 4 (April 2013): 999–1004. http://dx.doi.org/10.1109/tps.2013.2251670.

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17

Belosheev, V. P. "Leader discharge over a water surface in a Lichtenberg figure geometry." Technical Physics 43, no. 11 (November 1998): 1329–32. http://dx.doi.org/10.1134/1.1259193.

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18

Dul’zon, A. A., V. V. Lopatin, M. D. Noskov, and O. I. Pleshkov. "Modeling the development of the stepped leader of a lightning discharge." Technical Physics 44, no. 4 (April 1999): 394–98. http://dx.doi.org/10.1134/1.1259308.

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19

Yu, Wanshui, Qingmin Li, Jiyao Zhao, and Wah Hoon Siew. "Numerical Simulation of the Lightning Leader Development and Upward Leader Initiation for Rotating Wind Turbine." Machines 10, no. 2 (February 4, 2022): 115. http://dx.doi.org/10.3390/machines10020115.

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Lightning accidents seriously threaten safe operation of wind turbines because the influence mechanisms of wind turbine rotation on corona and upward leader initiation are, so far, not clear. A three-dimensional stochastic evolution model of the lightning downward leader was established by combining the dielectric breakdown model and the lightning current shunt method, according to which the charge density distribution of leader branches was determined. The corona and leader initiation mechanisms of rotating wind turbine were studied based on the 3D drift and diffusion model of ion flow in the neighboring space of a rotating wind turbine. The results show that due to blade rotation, the charged particles are unevenly distributed near the blade tip and the contours are in a strip-like shape. As the rotating speed increases, the blade tip is more susceptible to initiating corona discharge. Combining the three-dimensional stochastic development model of the lightning downward leader and ion distribution model near a rotating wind turbine, the initiation direction of the upward leader was analyzed, and in 66% of cases, the initiation direction of the upward leader on the blade tip was on the back side of the blade rotation.

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20

G. V. Podporkin, E. S. Kalakutsky, V.E. Pilshikov, and A. D. Sivaev. "Lightning Protection of Electric Power Overhead Distribution Lines by Long-Flashover Arresters in Russia." Journal of Energy - Energija 60, no. 1-4 (August 22, 2022): 101–9. http://dx.doi.org/10.37798/2011601-4269.

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A simple and effective method for lightning protection of power overhead distribution lines by long flashover arresters (LFAs) is presented. Even large lightning currents do not pose any threat to these arresters because the discharge develops in the air and not inside the device. LFAs, which are based on the creeping discharge effect, increase the lightning flashover length significantly and thus eliminate Power Arc Follow (PAF). To protect a line against induced overvoltages, a single arrester should be mounted on a pole. To protect a line against direct lightning strokes, LFA-M arresters should be mounted in parallel with each insulator. For covered-conductor overhead lines (CCL) using conductors with three-layer insulation a new lightning protection approach is suggested, involving use of antenna-type long flashover arresters whose essential component is the protected conductor itself. The essence of antennatype long flashover arresters (LFA-A) is that the arrester which is connected to the antenna gets flashed over well before the lightning leader comes in immediate contact with the line. The toroid-shaped antenna made of a metal tube is mounted on the covered conductor’s surface midway between the protector’s edge and the piercing clamp with the help of the toroid fixation unit. As the lightning leader progresses from a thunderstorm cloud to the CCL a high potential gets induced on the LFA antenna. A voltage drop that develops between the electrode and the zero-potential conductor core gives rise to development of a creeping discharge. Even before the lightning leader hits the line the creeping discharge channel flashes over the covered conductor’s surface Thereby the conductor insulation get bypassed by the discharge channel and thus protected against puncture. LFA’s main applications and field experience are presented.

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21

Matsui, Daisuke, Ariadi Hazmi, Teiji Watanabe, Nobuyuki Takagi, and Daohong Wang. "Discharge characteristics obtained with an impulse voltage simulating the lightning stepped leader." Journal of Atmospheric Electricity 28, no. 2 (2008): 63–69. http://dx.doi.org/10.1541/jae.28.63.

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22

Hayakawa, N., K. Hatta, S. Okabe, and H. Okubo. "Streamer and leader discharge propagation characteristics leading to breakdown in electronegative gases." IEEE Transactions on Dielectrics and Electrical Insulation 13, no. 4 (August 2006): 842–49. http://dx.doi.org/10.1109/tdei.2006.1667744.

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23

Yaoheng Xie, Hengxin He, Junjia He, and Chuanqi Wu. "The Effect of Corona Discharge on Leader Initiation in Long Air Gaps." IEEE Transactions on Plasma Science 42, no. 4 (April 2014): 890–95. http://dx.doi.org/10.1109/tps.2014.2305446.

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24

Belosheev, V. P. "Study of the leader of a spark discharge over a water surface." Technical Physics 43, no. 7 (July 1998): 783–89. http://dx.doi.org/10.1134/1.1259074.

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25

Shah, Wahab Ali, Hengxin He, Junjia He, and Yongchao Yang. "Continuous and Discontinuous Streamer Leader Propagation Phenomena under Slow Front Impulse Voltages in a 10-meter Rod-Plane Air Gap." Energies 11, no. 10 (October 2, 2018): 2636. http://dx.doi.org/10.3390/en11102636.

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Investigation of positive streamer-leader propagation under slow front impulse voltages can play an important role in the quantitative research of positive upward lightning. In this work, we performed a large-scale investigation into leader development in a 10-m rod–plane gap under a long front positive impulse. To describe the leader propagation under slow front impulse voltages, we recorded the leader propagation with a high-speed charge coupled device (CCD) camera. It is important to figure out this phenomenon to deepen our understanding of leader discharge. The observation results showed that the leader mechanism is a very complex physical phenomenon; it could be categorized into two types of leader process, namely, continuous and the discontinuous leader streamer-leader propagation. Furthermore, we studied the continuous leader development parameters, including two-dimensional (2-D) leader length, injected charge, and final jump stage, as well as leader velocity for rod–plane configuration. We observed that the discontinuous leader makes an important contribution to the appearance of channel re-illuminations of the positive leader. To clarify the above doubts under long front cases, we carried out extensive experiments in this study. The comparative study shows better results in terms of standard switch impulse and long front positive impulse. Finally, the results are presented with a view toward improving our understanding of propagation mechanisms related to restrike phenomena, which are rarely reported.

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26

Diaz, Oscar, Liliana Arevalo, and Vernon Cooray. "Parameter variation in leader channel models used in long air gap discharge simulation." Electric Power Systems Research 139 (October 2016): 32–36. http://dx.doi.org/10.1016/j.epsr.2015.11.033.

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27

Tan, M., and D. Lang. "Effectiveness of nurse leader rounding and post-discharge telephone calls on patient satisfaction." International Journal of Evidence-Based Healthcare 14, no. 4 (December 2016): 195–96. http://dx.doi.org/10.1097/01.xeb.0000511338.43833.68.

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28

Chen, Junhong, Peng Sun, Jinshu Li, Wendong Li, Yuan Li, Junbo Deng, Shengchang Ji, and Guan-Jun Zhang. "Surface discharge pattern of C₄F₇N/CO₂ mixture under negative impulse voltages." Applied Physics Letters 121, no. 17 (October 24, 2022): 171602. http://dx.doi.org/10.1063/5.0117535.

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Due to the excellent properties, C4F7N/CO2 mixture is the most concerned eco-friendly SF6 alternative gas. For a better understanding of the surface discharge characteristics, the surface discharge pattern of C4F7N/CO2 mixture under negative impulse voltages is investigated in this work. The morphology of the surface discharge is obtained by an optical method and a dust figure method. The structure of the surface discharge is established, which from the outside to the inside consists of electron cloud, streamer, streamer stem, and leader. The propagation pattern of the surface discharge in C4F7N/CO2 mixture under negative impulse follows the stepwise expansion pattern. The structure of the surface discharge in C4F7N/CO2 mixtures with different ratios and SF6 has no obvious difference, and the propagation pattern is also the same. The results of this work can help to better understand the surface discharge phenomenon and the insulation characteristics of C4F7N/CO2 mixture.

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Zhao, Shixin, Chengxun Yuan, А. А. Кудрявцев, О. М. Жеребцов, and Г. Д. Шабанов. "Исследование динамики формирования плазмоидов в гатчинском разряде." Журнал технической физики 91, no. 7 (2021): 1108. http://dx.doi.org/10.21883/jtf.2021.07.50952.342-20.

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The results of studies of the Gatchina discharge carried out at the Harbin Technological University (China) are presented. The Gatchina discharge is mainly used to create an analogue of ball lightning in the ordinary atmosphere of a laboratory. Most of the research on this discharge by various groups of scientists is devoted to the study of the first phase of the discharge, when an electric discharge is galvanically coupled to an electrode. This is due to the fact that many researchers consider this phase of the discharge to be decisive for the subsequent long-term existence of an autonomous luminous formation - the second phase of the discharge. In this paper, in comparison with similar works, the leader-streamer process on the water surface was demonstrated more fully and with a better resolution. The use of the filter made it possible to better show the role of leaders, streamers, and the ionization region in the immediate vicinity of the water surface and to clarify some of the processes occurring in the autonomous phase of the discharge. In the wavelength range of 400-500 nm, the autonomous luminous formation showed a longer lifetime in the form of a spherical shape than when observed in "white" light. With a sharp increase in the amount of substance introduced to the cathode, a new physical effect was recorded, which consists in the fact that in the medium of an ordinary atmosphere, a complex formation of a white color is formed without losing contact with the electrode (cathode). By varying the electrical conductivity and initial voltage, an unexpectedly small luminous formation with a diameter of 15-17 mm was obtained for the first time, which was not previously observed in a Gatchina discharge. Key words: Gatchina discharge, plasmoid, long-lived luminous formations, plasma sheet, space charge, virtual cathode, ball lightning. By varying the electrical conductivity and the initial voltage, an unexpectedly small luminous formation with a diameter of 15-17 mm was obtained for the first time, which was not previously observed in the Gatchina discharge.

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30

Sasaki, Akira, Susumu Kato, Eiichi Takahashii, Yasuaki Kishimoto, Takashi Fujii, and Seiji Kanazawa. "Simulation of discharge in insulating gas from initial partial discharge to growth of a stepped leader using the percolation model." Japanese Journal of Applied Physics 55, no. 2 (January 13, 2016): 026101. http://dx.doi.org/10.7567/jjap.55.026101.

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31

Wang, Yanhui, Yingchang Min, Yali Liu, and Guo Zhao. "A New Approach of 3D Lightning Location Based on Pearson Correlation Combined with Empirical Mode Decomposition." Remote Sensing 13, no. 19 (September 28, 2021): 3883. http://dx.doi.org/10.3390/rs13193883.

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To improve the accuracy of pulse matching and the mapping quality of lightning discharges, the Pearson correlation method combined with empirical mode decomposition (EMD) is introduced for discharge electric field pulse matching. This paper uses the new method to locate the lightning channels of an intra-cloud (IC) lightning flash and a cloud-to-ground (CG) lightning flash and analyzes the location results for the two lightning flashes. The results show that this method has a good performance in lightning location. Compared with the pulse-peak feature matching method, the positioning results of the new method are significantly improved, which is mainly due to the much larger number of positioning points (matched pulses). The number of located radiation sources has increased by nearly a factor of seven, which can significantly improve the continuity of the lightning channel and clearly distinguish the developmental characteristics. In the CG flash, there were three negative recoil streamers in the positive leader channel. After the three negative recoil streamers were finished, taking approximately 1 ms, 12 ms, and 2 ms, respectively, the negative leader channel underwent a K-process. The three negative recoil streamers are not connected to the K-processes in the negative leader channel. We think that the three negative recoil streamers may have triggered the three K-processes, respectively.

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32

Yue, Yishi, Yanhui Zou, Haiyue Wang, Fuyong Huang, and Cheng Wang. "Research on observation method of leader discharge thermal expansion based on quantitative schlieren technique." IOP Conference Series: Earth and Environmental Science 310 (September 5, 2019): 032059. http://dx.doi.org/10.1088/1755-1315/310/3/032059.

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33

Zhao, Xiangen, Lipeng Liu, Yishi Yue, Hengxin He, Lei Liu, and Junjia He. "On the use of quantitative Schlieren techniques in temperature measurement of leader discharge channels." Plasma Sources Science and Technology 28, no. 7 (July 25, 2019): 075012. http://dx.doi.org/10.1088/1361-6595/ab1c3e.

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Akita, Manabu, Satoru Yoshida, Yoshitaka Nakamura, Takeshi Morimoto, Tomoo Ushio, Zen Kawasaki, and Daohong Wang. "Effects of Charge Distribution in Thunderstorms on Lightning Propagation Paths in Darwin, Australia." Journal of the Atmospheric Sciences 68, no. 4 (April 1, 2011): 719–26. http://dx.doi.org/10.1175/2010jas3597.1.

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Abstract The charge distributions in a thundercloud play an important role in the initiation and propagation of lightning discharges. To further understand the effects of charge distributions on lightning discharge, the authors conducted a very high-frequency (VHF) lightning observation campaign during the 2006/07 monsoon in Darwin, Australia, using a VHF broadband digital interferometer (DITF). A C-band polarimetric weather radar to estimate the precipitation profiles such as hydrometeor classification was operated by the Bureau of Meteorology (BOM) Research Centre. Cloud-to-ground (CG) and intracloud (IC) flashes were initiated from the outer and the inner parts of the upper side of the graupel regions, respectively. In the cases of CG flashes, the negative leaders travel first about 10 km horizontally through positive charge regions and then begin to bend toward the ground when they reach the edge of the positive charge regions where there is no graupel region underneath. In contrast, in the cases of the IC flashes the negatively charged graupel regions block the downward developments of negative leaders. It is noted that positive charge regions could facilitate the extension of the horizontal negative leader. These results may suggest that lightning flash types are closely dependent on their initiation locations and the surrounding charge distributions. The experimental results are consistent with other previous observation results and charge model simulations.

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Shi, Tao, Gaopeng Lu, Yanfeng Fan, Xiao Li, and Yang Zhang. "A Comprehensive Study on the Improved Radio-Frequency Magnetic Field Measurement for the Initial Upward Leader of a Negative Rocket-Triggered Lightning Flash." Remote Sensing 13, no. 8 (April 15, 2021): 1533. http://dx.doi.org/10.3390/rs13081533.

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The spectrum analysis of the lightning current in the experiment campaign of 2019 reveals that the lightning current waveform contains rich medium-frequency (MF) radiation signals in the initial stage. However, there is a lack of resolution for MF signals by using conventional magnetic sensors. The bandwidth of radio-frequency magnetic field measurement is improved by extending to 20 kHz–1.2 MHz in the Guangdong Comprehensive Observation Experiment on Lightning Discharge (GCOELD). During the previously noticed “quiet period” that can only maintain the upward propagation with relatively small-scale breakdown, magnetic pulses of quiet period (MPQPs) are discerned more clearly than the previous experiment in GCOELD. Aided by the improvement of a magnetic sensor, this paper captures richer magnetic field signals radiated from the weak discharge of the precursory phage than previous experiments in GCOELD. The analysis shows that both aborted UPLs and UPLs are caused by weak discharge pulses called initial precursor pulses (IPPs), which are very similar to the amplitude of the streamer discharge obtained in the laboratory. In summary, the signals detected by an improved magnetic sensor will provide an important reference for exploring the pulse characteristics of the whole discharge process and formation mechanism of the UPL in the initial stage of triggered lightning.

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Guo, Xiufeng, Qilin Zhang, and Jinbo Zhang. "Improvement of Corona Discharge Model and Its Application on Simulating Corona Discharge in the Presence of Wind." Mathematical Problems in Engineering 2017 (2017): 1–10. http://dx.doi.org/10.1155/2017/9853439.

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To evaluate the effect of wind on corona discharges occurring on the tip of a grounded rod during a negative charging process of thundercloud, a two-dimensional numerical model has been improved by considering the wind velocity as a driving force for the movement of the corona charges. It was found that not only wind speed but also wind direction have a significant effect on the distribution of corona charges, the local electric field around the rod, and the corona current. (1) Under the same wind speed, a larger horizontal wind can result in less accumulation of corona charges, a larger electric field, and a larger corona current. However, when the speed is less than 5 m s−1, the effect of wind direction on the corona current was weak. (2) Under the same wind direction, a larger wind speed can cause a larger corona current. However, when the horizontal wind component is smaller than the vertical, the larger wind speed would cause a smaller electric field. Thus, it is necessary to take the effects of the wind direction into consideration, rather than to consider its speed only, when studying the corona discharge and its effects on the upward leader.

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Li, Zhijun, Weijiang Chen, Chengrong Li, Kai Bian, Huiwen He, Feng Huo, and Mian Fan. "Influence of rate of voltage rise on positive leader inception in long-air-gap discharge." AIP Advances 12, no. 2 (February 1, 2022): 025119. http://dx.doi.org/10.1063/5.0072072.

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Li, Zhijun, Shengxin Huang, Jianwei Gu, and Tianyu He. "A Contribution to the Investigation of Leader Tortuosity in Positive Long Rod-Plane Air Discharge." IEEE Access 7 (2019): 170442–47. http://dx.doi.org/10.1109/access.2019.2949646.

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Currie, Graeme, Tina Kiefer, and Dimitrios Spyridonidis. "From what we know to what we do: enhancing absorptive capacity in translational health research." BMJ Leader 4, no. 1 (November 12, 2019): 18–20. http://dx.doi.org/10.1136/leader-2019-000166.

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BackgroundGlobally, evidence about what works is slow to translate into frontline healthcare delivery. As a response, government policy has focused on translational health initiatives, such as the National Institute for Health Research funded Applied Research Collaborations in England. Concepts from organisation science prove useful to support such translational initiatives. We critique the application of two organisation science concepts linked to the broad domain of what is commonly termed ‘knowledge mobilisation’ in healthcare settings, specifically ‘knowledge brokers’ and ‘absorptive capacity’, to provide lessons for leaders of translational initiatives.ResultsThe presence of knowledge brokers to ‘move from what we know to what we do’ in healthcare delivery appears necessary but insufficient to have a system level effect. To embed knowledge brokers in the wider healthcare system so they draw on various sources of evidence to discharge their role with greatest effect, we encourage leaders of translational health research initiatives to take account of the concept of absorptive capacity (ACAP) from the organisation science literature. Leaders should focus on enhancing ACAP though development of ‘co-ordination capabilities’. Such co-ordination capability should aim not just to acquire different types of evidence, but to ensure that all types of evidence are used to develop, implement and scale up healthcare delivery that best benefits patients. Specific co-ordination capabilities that support translation of evidence are: clinician involvement in research and its implementation; patient and public involvement in research and its implementation; business intelligence structures and processes at organisational and system level.ConclusionAttention to the dimensions and antecedents of ACAP, alongside the implementation of the knowledge brokering solution, in translational health research initiatives, is likely to better ensure the latter’s success.

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Villa-Roel, C., S. R. Majumdar, R. Leigh, A. Senthilselvan, M. Bhutani, B. Borgundvaag, E. Lang, R. J. Rosychuk, and B. H. Rowe. "LO64: Emergency department directed multifaceted interventions to improve outcomes after asthma exacerbations: a 3-armed randomized controlled trial." CJEM 19, S1 (May 2017): S50. http://dx.doi.org/10.1017/cem.2017.126.

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Introduction: Approximately 20% of Canadians who present to emergency departments (EDs) with acute asthma relapse within 4 weeks of discharge. The reasons are likely multi-factorial; however, the lack of timely primary care provider (PCP) follow-up and inadequate patient self-management are thought to be important variables. Therefore, we tested the effectiveness of ED-directed multifaceted interventions that targeted PCPs and enhanced patient self-management to reduce asthma relapse following ED discharge. Methods: Adults with acute asthma discharged from 6 Alberta EDs were randomly allocated, in a centralized and concealed manner, to receive usual care (UC), opinion leader [OL] guidance to their PCPs, or OL guidance + nurse case-management [OL+CM] for patients (NCT01079000). The main outcome was asthma relapse within 90-days of ED discharge. Secondary outcomes included PCP visits, time to relapse, hospitalizations and asthma-related quality of life (QoL). Outcomes were collected independently and assessors were masked to intervention assignment. Results: From 943 screened patients, 367 patients were allocated to the study arms (UC=146; OL=110; OL+CM=111). Median age was 28 years, 64% were women, median peak flow at discharge was 350 L/min; 77% were discharged home on prednisone and 85% on either inhaled corticosteroids (ICS) or ICS/long-acting β2-agonists. Compared with UC, both interventions significantly increased rates of relapse at 90-days: UC=12%, OL=28%, OL+CM=19%; p=0.006. Based on an absolute increased risk of 0.16 (95% CI: 0.05, 0.25), the number needed to treat for harm was 6 (95% CI: 3.9, 19.0) for the OL arm. Across study differences in PCP follow-up visits, time to relapse, hospitalizations or asthma-related QoL were not identified. Conclusion: Two different theory-informed and evidenced-based interventions intended to decrease asthma relapse robustly and significantly increased rates of relapse compared with UC. While the reasons for these unintended consequences require further study, we caution against the adoption of similar interventions by other EDs.

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Zhang, Yalin, Yunzhong Song, and Shumin Fei. "Consensus Design for Heterogeneous Battery Energy Storage Systems with Droop Control Considering Geographical Factor." Applied Sciences 10, no. 2 (January 20, 2020): 726. http://dx.doi.org/10.3390/app10020726.

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This paper proposes a hierarchical control strategy to coordinate battery energy storage devices based on a multi-agent system. The heterogeneous nature of the battery volume is paid much more attention in designing the proportional protocol of the consensus controller. Besides that, a cluster algorithm based on Minimum Spanning Tree (MST) is suggested to represent geographical factor, and on account of that, each Battery Energy Storage System (BESS) is classified into its specific cluster zone. Further, an active leader is assigned to be in charge of information from the external side in every cluster. The consensus algorithm reconciles all clusters in a step-by-step way. Energy level, voltage, frequency and active/reactive power sharing of every BESS can reach consensus by an information exchange within and among clusters respectively. Further, a virtual leader is taken into the active leader role in directing frequency and voltage to the reference values. To verify the consensus algorithm, a modified IEEE 57-bus is employed for time-domain simulations in an islanded mode and all BESSs are working in a discharge model.

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Ohtsuka, Shinya, Yuta Nakayama, and Yuta Suzuki. "Optical Measurement of Partial Discharge Propagation Phenomena including Leader Transition in SF₆ Gas." IEEJ Transactions on Power and Energy 141, no. 2 (February 1, 2021): 196–206. http://dx.doi.org/10.1541/ieejpes.141.196.

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Tan, Mary, and Dora Lang. "Effectiveness of nurse leader rounding and post-discharge telephone calls in patient satisfaction: a systematic review." JBI Database of Systematic Reviews and Implementation Reports 13, no. 7 (July 2015): 154–76. http://dx.doi.org/10.11124/01938924-201513070-00015.

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Tan, Mary, and Dora Lang. "Effectiveness of nurse leader rounding and post-discharge telephone calls in patient satisfaction: a systematic review." JBI Database of Systematic Reviews and Implementation Reports 13, no. 7 (July 2015): 154–76. http://dx.doi.org/10.11124/jbisrir-2015-2013.

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Juwita, Helmi, Elly L.Sjattar, Abdul Majid, and Sartika Lukman. "Kolaborasi Multidisiplin Pelaksanaan Discharge Planning." Aksiologiya: Jurnal Pengabdian Kepada Masyarakat 5, no. 4 (November 19, 2021): 524. http://dx.doi.org/10.30651/aks.v5i4.5079.

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Discharge planning adalah suatu proses multidisplin yang melibatkan Profesioanal Pemberi Asuhan (PPA) dan Manajer Pelayanan Pasien (MPP) yang bertujuan untuk mengurangi lama tinggal atau perawatan di rumah sakit, mencegah terjadinya readmisi dan meningkatkan kordinasi layanan setelah keluar dari rumah sakit. Penelitian ini bertujuan untuk mengevaluasi kolaborasi multidisiplin pelaksanaan discharge planning di RSUD Haji Makassar dengan menggunakan pendekatan observasional pre-post implementasi pendokumentasian discharge planning dan metode wawancara dalam bentuk focus group discussion (FGD) terhadap kepala bidang keperawatan, kepala ruangan, ketua tim, perawat pelaksana dan tim pokja. Instrumen yang digunakan adalah instrumen wawancara dan instrumen discharge planning terintegrasi. Hasil yang didapatkan yaitu pendokumentasian discharge planning di RSUD Haji Makassar belum optimal sehingga dilakukan beberapa program kegiatan yaitu studi literature, penyegaran tim, pelatihan, pembuatan panduan, form dan SOP discharge planning, uji coba form dan evaluasi. Setelah implementasi didapatkan peningkatan pendokumentasian discharge planning menjadi 77.7%, Selain itu, discharge planning juga dilakukan pada saat pasien masuk di ruang rawat inap hingga pasien sebelum pulang. Oleh karena itu, pada penelitian selanjutnya dibutuhkan penelitian terkait pendokumenatsian discharge planning secara multidisiplin, serta perlunya monitoring dan evaluasi terhadap pelaksanaan discharge planning. Multidisciplinary Collaboration on Discharge Planning Implementation ABSTRACTDischarge planning is a multidisciplinary process that involves the Professional Care Provider (PPA) and the Patient Services Manager (MPP) aims to reduce the length of stay or treatment in the hospital, prevent readmissions and improve service coordination after discharge from the hospital. This research to evaluate multidisciplinary collaboration implementation of discharge planning in Haji Hospital Makassar using an observational approach pre-post implementation of discharge planning documentation and interview method in focus group discussions (FGD) of head nurse, chief nurse, team leader, nurse associate, and team. The instrument used was an interview instrument and an integrated discharge planning instrument. The results obtained were documentation of discharge planning in Haji Hospital Makassar was not optimal so that several program activities were literature study, team refreshment, training, making guidelines, form and SOP discharge planning, trial form, and evaluation. After implementation, there was an increase in the documentation of discharge planning to 77.7%. In addition, discharge planning was also carried out when the patient entered the inpatient room to the patient before leaving. Therefore, further research is needed in order to discharge planning documentation by a multidisciplinary team, monitoring, and evaluation of the discharge planning implementation. Keyword: Multidisciplinary Collaboration; Discharge Planning

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Huang, Xin, Ping Yuan, Ruibin Wan, Tingting An, Guorong Liu, Xuejuan Wang, Hong Deng, and Wangsheng Wang. "Conduction characteristics of lightning dart leader channel and its influence on the corresponding return stroke discharge intensity." Physics of Plasmas 28, no. 12 (December 2021): 123512. http://dx.doi.org/10.1063/5.0064417.

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Chen, She, Rong Zeng, Chijie Zhuang, Xuan Zhou, and Yujian Ding. "Experimental Study on Branch and Diffuse Type of Streamers in Leader Restrike of Long Air Gap Discharge." Plasma Science and Technology 18, no. 3 (March 2016): 305–10. http://dx.doi.org/10.1088/1009-0630/18/3/15.

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Akishev, Y., V. Karalnik, M. Medvedev, A. Petryakov, N. Trushkin, and A. Shafikov. "Gas flow influence on streamer-to-leader transition in surface barrier discharge in air at atmospheric pressure." Journal of Physics: Conference Series 789 (January 2017): 012001. http://dx.doi.org/10.1088/1742-6596/789/1/012001.

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Biagi, Christopher J., M. A. Uman, J. D. Hill, and D. M. Jordan. "Observations of the initial, upward-propagating, positive leader steps in a rocket-and-wire triggered lightning discharge." Geophysical Research Letters 38, no. 24 (December 28, 2011): n/a. http://dx.doi.org/10.1029/2011gl049944.

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Sasamoto, Ryo, Takao Matsumoto, Yasuji Izawa, and Kiyoto Nishijima. "Gas Heating and Streamer-to-Leader Transition of Impulse Surface Discharge on Quartz Glass in Atmospheric Air." IEEE Transactions on Plasma Science 43, no. 12 (December 2015): 4210–15. http://dx.doi.org/10.1109/tps.2015.2494628.

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