2014 Annual Meeting of The Institute of Electrostatics JapanHiroshima International University
September 7-8, 2014

9aD-1
September 9th (Tue.), <10:00-12:00>
Room 3

Effect of the electronegative gas on neutralization
characteristics of a corona-discharge-type ionizer*,Yudi KRISTANTO*,Wanting HE*,Takeshi MATSUO*,Naoyuki SATO*,Kazuo
OKANO**,Takashi IKEHATA**Institute of Applied Beam Science, Ibaraki University **Department of ElectricalEngineering, The Polytechnic University

Abstract:
We investigated the neutralization characteristics of a corona-discharge-type ionizer in different atmospheric gases; ambient air, pure nitrogen, mixed
N2-O2 and N2-SF6 gases with changing the partial pressure of O2 and SF6,
respectively. The product final voltage VPF in pure nitrogen shows a deviation toabout -2 kV. However, by introducing SF6, VPF reduced to the one equivalent toair. The amount of SF6 gas needed to improve the ion balance is many orders ofmagnitude smaller than that of O2 gas.

2014 Annual Meeting of The Institute of Electrostatics Japan
Hiroshima International University
September 7-8, 2014

9aD-2
September 9th (Tue.), <10:00-12:00>
Room 3Development of the Corona Discharge Air Ionizer Applied
Electrical Field of Charged Surface○Takashi Sato*,Takashi Ikehata*, Kazuo Okano***Institute of Applied Beam Science, Ibaraki University **Department
Electrical Engineering, The Polytechnic UniversityofAbstract:
This paper proposed a new type of corona discharge air ionizer, applied
electrical field of charged surface to neutralize the object. To achieve that, thecorona discharge air ionizer is operated extremely close to the charged surface.
There's a problem that it may turn the corona discharge air ionizer into anelectrostatic charger. To avoid becoming an electrostatic charger, emitter voltage
operated at lower than conventional the corona discharge air ionizer, whichgenerates few ions. We experimented characteristics of neutralizing the charged
surface changing factors [Waveform, Voltage, Frequency, Height], reported
comfortable value based on these result2014 Annual Meeting of The Institute of Electrostatics Japan
Hiroshima International University
September 7-8, 2014

9aD-3
September 9th (Tue.), <10:00-12:00>
Room 3The electrode materials and preventing the erosion of themon corona-discharge electrodes of the ionizer for cleanrooms part2○Masanori SUZUKI*，Tomokatsu SATO*, ***Technical R&D Center, Techno Ryowa Ltd., **Dept. of Environment and Lifesciences, Toyohashi University of Technology

Abstract:
In recent years, static electricity has become a major cause of
production yield loss in LSI or LCD production processes. However it wasserious problem that corona-discharge electrodes of the ionizer for eliminating
static electricity in clean rooms emit fine particles through the erosion caused byion sputtering. In our previous paper, we described the cleanroom use ionizer
prevented the particle generation from its electrodes and we also reported theresult we evaluated our developed electrode prevented the erosion caused byion sputtering. In this paper, we will report the result we evaluated new
erosion-proof electrodes we developed through the long endurance test and themeasurement of metal contamination on the surface of silicon wafers.

2014 Annual Meeting of The Institute of Electrostatics Japan
Hiroshima International University
September 7-8, 2014

9aD-4
September 9th (Tue.), <10:00-12:00>
Room 3

Bipolar-Type Electrostatic Ionizer used in Pneumatic
Powder Transport Facility
Kwangseok CHOI*、Teruo SUZUKI**、Tomofumi MOGAMI**、MizukiYAMAGUMA**JNIOSH、**Kasuga Denki INC

Abstract:
As a method to prevent or mitigate explosion due to electrostatic
discharges during the loading of polymer granules in a metal silo, we havedeveloped a novel bipolar-type electrostatic ionizer. In this study, we investigatedexperimentally the practical version of the bipolar electrostatic ionizer with apneumatic powder transport facility. As a sample, 300 kg of polypropylene (PP)
granules 3 mm in size was employed in this study. The specific charge of PP
was clearly decreased by approximately 85 percent with the novel bipolarelectrostatic ionizer. The brush discharges, as well as the incendiary bulk
surface discharges, completely died out inside the silo when using the novelbipolar electrostatic ionizer.

2014 Annual Meeting of The Institute of Electrostatics Japan
Hiroshima International University
September 7-8, 2014

9aD-5
September 9th (Tue.), <10:00-12:00>
Room 3

Cause of a Fire that occurred in Polymerization Tank
Hiroyuki TAMURA、Toshiyuki WATARAINational Research Institute of Fire and Disaster

Abstract:A fire occurred when a worker cleaned the inside of a polymerization
tank, and the worker was injured. Because the toluene was used in the tank, it
was thought that the evaporating toluene had been ignited. The electrostatic
discharge in the tank was doubted as a fire cause. We examined theelectrostatic charge, the electrostatic discharge, and the discharge energy. As aresult, strong electrostatic charge happened by following.- Drawing out a rag
made of cotton for wiping machines from a bag- Washing the rags by rubbing in
the toluene The discharge energy exceeded the minimum ignition energy of thetoluene though it was the electrostatic discharge between ungrounded
conductors such as a metal pail and a human body. It is necessary to take thegrounding of conductors surely on the site in the flammable atmosphere toprevent the electrification and the electrostatic discharge.

2014 Annual Meeting of The Institute of Electrostatics JapanHiroshima International University
September 7-8, 2014

9aD-6
September 9th (Tue.), <10:00-12:00>
Room 3

Analysis current waveforms induced by charged walking
human bodies○Nakao Kazuki, Nishimura Ryo*Graduate School of Engineering, Tottori University

Abstract:
We aim to construct a non-contact detection system of human walking
motion for personal identification by using variation of charges in walking humanbodies. This system measures very small charge fluctuations caused by walking
as induction currents flowing to a grounded electrode. Fourier analyses werecarried out for the obtained induced current waveforms. Comparing the results of
the Fourier analyses, features of individuals can be detected. We also found thata number of steps a minute gives significant effects on the results of the Fourieranalyses for experiments under the condition of fixed walking pace, walking
velocity and distance between the detection electrode and walking human andthat the difference of apparel gives little difference in the waveforms of Fourier
analyses of induced currents under the same environmental conditions.

2014 Annual Meeting of The Institute of Electrostatics Japan
Hiroshima International University
September 7-8, 2014

9aD-7
September 9th (Tue.), <10:00-12:00>
Room 3Detection Technique of Electrostatic Induction Current
Generated by Change of Electric Potential of Human Bodyin Walking Motion
Koichi Kurita
Kinki University

Abstract:
I here present a method for measuring human physical activity, which isbased on detecting the electrostatic induction current generated by the walking
motion under non-contact and non-attached conditions. A theoretical model forthe electrostatic induction current generated because of a change in the electric
potential of the human body is also proposed. The electric potential of thesubject is determined by integrating the electrostatic induced current. The valuesof the estimated electric potential are qualitatively in good agreement with thoseobtained in conventional experiments by using the ordinary contact-type handelectrode. By comparing the obtained electrostatic induction current with thetheoretical model, it becomes obvious that this model effectively explains thebehavior of the waveform of the electrostatic induction current. The normal
walking motions of daily living are recorded using a portable sensor
measurement located in an ordinary house. The obtained results show thatdetailed information regarding physical activity such as a walking cycle can beestimated using our proposed technique. This suggests that the proposed
technique, which is based on the detection of the walking signal, can be
successfully applied to the estimation of human physical activity.