2015 Annual Meeting of The Institute of Electrostatics JapanTokyo Metropolitan University
September 24-25, 201524aA-1
September 24th (Thu.), <10:00-12:00>
Room 1

Surface charging when the water droplet dropped with acharge (Second report)○Yusuke FUTAMI and Hirofumi SHIMOKAWA
Kanagawa Institute of Technology

Abstract:
This report examined charging characteristics of the surface in dropping
water droplet which was charged on super-water-repellent agent (HIREC1100).
In the previous report, it was shown the surface was charged negatively, when+200pC water droplet was dropped in the water-repellent surface. Is this report,
the similar experiment was carried out in water droplet which electric charge
which in bigger then +200pC. The surface was charged positively in case of the+300pC water droplet. And, the surface was charged negatively in case of+220pC. Surface density of charge in which the surface in not charge see to be
24~30μC / m2.

2015 Annual Meeting of The Institute of Electrostatics JapanTokyo Metropolitan University
September 24-25, 201524aA-2
September 24th (Thu.), <10:00-12:00>
Room 1

Current waveform and electric charge in electrostaticspraying(second report)
Kazumasa CHIKU，Hirofumi SHIMOKAWA
Kanagawa Institute of Technology

Abstract:
In this study, current waveform detected in the electrostatic atomizationby the nozzle was made to synchronize with the image of high-speed camera.
The change of the process according to the resistivity and the nozzle gauge ofthe electrostatic atomization phenomenon is observed from the synchronization,and the electrification process is revealed. The electric charge was calculated
from pulse current form in dependent on the value of applied voltage and thenozzle gauge. The electric charge when the nozzle 23G has changed irregularly.
After the droplets from the liquid thread breakup, the electric charge is increasedby the liquid surface or thread vibrates greatly.

2015 Annual Meeting of The Institute of Electrostatics JapanTokyo Metropolitan University
September 24-25, 201524aA-3September 24th (Thu.), <10:00-12:00>
Room 1

Flow Electrification between Pure Water and PFA with
Intermittent Flow
○Daichi Obata, Hiroshi Tasaka, Sunao Katsuki, Hidenori Akiyama
Graduate School of Science and Technology, Kumamoto University

Abstract:
Flow electrification phenomenon between pure water and PFA(PerFluoroAlkoxyethylene) tube was described in this paper. Essentially, purewater flowing in a PFA tube is positively electrified, but negative charges on thehead of the intermittent flow are observed in high Reynolds number conditions.
The amount of the negative charges depends on flow velocity, tube length, andinitial residual charges on the PFA tube. These results indicate that initialresidual charges on the PFA tube are collected by the head of water flow. In spiteof the relatively high conductivity of pure water, the collected negative charges
are not diffused because the two-phase flow condition is mixed and atomized,
which means insulated condition.

2015 Annual Meeting of The Institute of Electrostatics JapanTokyo Metropolitan University
September 24-25, 201524aA-4September 24th (Thu.), <10:00-12:00>
Room 1

Thermal Endurance of Multi-doped Nanocomposite
Polymeric Insulating Material Using Azo-benzoic Compound
Yoshiaki YAMANO
faculty of Education, Chiba University

Abstract:
Thermal endurance evaluation according to IEC 60216 series wascarried out on the multi-doped nano-composite polymeric insulating material
which we newly designed for high resistance to the electrical tree degradation.
The base material was LDPE, which was added with nano-particle of Al2O3 andazobenzoic compound. The size of the particle is about 50 nm in average. Theaging test was carried out using 3 chambers controlled at 85 ºC, 90 ºC and 95 ºC,individually. The results indicated that RTE of the test sample was almost 40 %higher than that of LDPE, which indicates very high performance against thethermal degradation.

2015 Annual Meeting of The Institute of Electrostatics JapanTokyo Metropolitan University
September 24-25, 201524aA-5
September 24th (Thu.), <10:00-12:00>
Room 1

Observation of Ultra-short Pulsed Discharge in SupercriticalCarbon Dioxide〇Miyuki OTA*, Tomohiro FURUSATO**, Takahiro IMAMICHI*, Takashi
SAKUGAWA*, Sunano KATSUKI*, and Hidenori AKIYAMA**Graduate School of science and technology, Kumamoto University, **Graduate
School of Engineering, Nagasaki University

Abstract:
This paper deals with pre-breakdown phenomena in supercritical carbon
dioxide (SC-CO2) with ultra-short positive pulsed voltages. Previously, we
studied a cylindrical shock wave propagated from a filament-like positive
streamer channel with a rise time of 90 ns, peak voltage of 60 kV and half-widthof 170 ns. For this study, we developed an ultra-short nanosecond pulse
generator with a rise time of 6.6 ns, peak voltage of 9 kV and half-width of 15 ns.
The voltage was applied to a needle-to-plane electrode in SC-CO2. The gap
length was set at approximately 320 µm. A filament-like streamer was observed
using the shadowgraph method as with our previous study.
Furthermore, unique images of shock waves were observed in which theshock wave appeared to propagate from the vicinity of the needle tip. In addition,a relatively weak shock waves along the streamer channel were also observed.
This data allowed us to infer that heating of the streamer vicinity of the needle tip
was enhanced compared with the streamer tip.

2015 Annual Meeting of The Institute of Electrostatics JapanTokyo Metropolitan University
September 24-25, 201524aA-6
September 24th (Thu.), <10:00-12:00>
Room 1

Measurement of infrared emission spectrometry ofO2(a1∆g) in atmospheric-pressure helium plasma jet○Yuki Inoue, Ryo Ono
Graduate School of Frontier Sciences, The University of Tokyo

Abstract:
The atmospheric-pressure helium plasma jet is an important device forplasma biomedical applications. We measured the density of singlet deltaoxygen O2(ɑ1∆g) in the plasma jet. O2(ɑ1∆g) is effective in the treatment ofblood sterilization and cancer. The measurement result shows the O2(ɑ1∆g)density under the high voltage electrode is approximately 2-8 ppm. TheO2(ɑ1∆g) density become maximum when the oxygen concentration is 0.2%
and the peak-to-peak voltage is 11kV.

2015 Annual Meeting of The Institute of Electrostatics JapanTokyo Metropolitan University
September 24-25, 201524aA-7
September 24th (Thu.), <10:00-12:00>
Room 1DEVELOPMENT OF LOW IMPEDANCE HIGH VOLTAGE
NANOSECOND PULSED POWER GENERATOR〇Satoru MATSUMOTO*, Shintaro KODAMA*, Douyan WANG**, Takao
NAMIHIRA** and Hidenori AKIYAMA *** Graduate School of Science and Technology, Kumamoto University , **Instituteof Pulsed Power Science

Abstract:
This study focuses on improving our nanosecond pulse generator bychanging insulation and dielectric medium and improving the configuration of thespark gap switch (SGS). The insulation and dielectric medium were changed
from silicone oil to ethylene glycol, with εr referring to the dielectric constant. The
dielectric constant of silicone oil and ethylene glycol are 2.7 and 44. Therefore,characteristic impedance of silicone oil and ethylene glycol become about 50 Ωand 12.5 Ω. The pulse width of silicone oil was extended from 5.0 ns to 20 ns inethylene glycol. Therefore, pulse width can be varied by changing the length of
the triaxial Blumlein line, with the length of the line 500 mm under the previous
configuration but 125 mm using the reconfigured generator. The previous SGS
path was longer than the one we have currently. Therefore, due to inductanceinside the switch, we developed a low inductance new SGS. It is developed fivegenerators by combining the three previous factors. The output current ofGenerator 5 is about 2.6 times that of Generator 1. Generator 5 has the highest
power, making it the best generator.