Abstract of Papers Presented to 2006 Annual Meeting of The Institute of Electrostatics Japan

(Followings are presentation number, title, authors, their affiliations and abstract for each paper)

25aD-1

“Spark Ignition of Hydrogen-Air Mixture: Measurement of OH Density and Gas Temperature Using Laser-Induced Fluorescence”

The University of Tokyo

○Ryo Ono, Tetsuji Oda

Gas temperature and density of OH radicals are measured using laser-induced fluorescence (LIF) in an incipient flame of hydrogen-air mixture ignited by a spark discharge. When a hydrogen(50\%)-air mixture is ignited with E = 1.35Emin, where E is the spark energy and Emin is the minimum ignition energy, OH density decreases for 100 us after the spark discharge from 2x10(16) cm(-3) to 2x10(15) cm(-3), then it is approximately constant for the next 100 us. On the other hand, the gas temperature increases for 200 us after the spark discharge from 900 K to 1400 K. It shows a heating of the gas by the exothermic reaction of hydrogen-air combustion. The temperature increase is not observed when the mixture is not ignited with E = 0.95Emin.

25aD-2

“Measurement of static charging on anti-static inner bags used with flexible intermediate bulk containers”

*Taiyokogyo Co.，**Shishido Electrostatic,Ltd.，***Technical Institution of Industrial Safety

○Atsushi Yamanobe*，Ken Sawaki*，Tsutomu Kodama**，and Fusao Izumi***

Anti-static flexible intermediate bulk containers (FIBCs) are getting more popular in industry for handling bulky stuffs such as powder and pellets as consciousness of electrostatic hazards with FIBCｓ increases. Various anti-static inner bags are also developed because inner bags have to been used together with FIBCs for contamination free. In order to use inner bags safely, static charging on insulating and anti-static inner bags, which were combined with different types of FIBCs, was measured during discharging of pellets. As a result, the combination of a dissipative inner bag and Type C FIBCs was found appropriate for the safe use.

25aD-3

“Suppression of Incendiary Discharge Occurring from Nozzle-Type Electrostatic Eliminator”

Kasuga Denki,Inc.

Teruo Suzuki

In order to prevent dust explosions in a large silo, we have developed a flange-type electrostatic eliminator, provided with sixteen ionizing needle electrodes, and its performance have also evaluated with the full-size pneumatic powder transport facility. As the results, when a high-voltage DC is applied to the needle electrodes of the eliminator, the performance was superior to the eliminator to which a high-voltage AC (50 Hz) has been applied. On the other hand, the eliminator by abnormal operations can cause rarely incendiary discharges in explosive atmosphere which happens to go on explosions in industry. Accordingly, DC type eliminator remains to be investigated whether it can be controlled safely incendiary discharges. This paper deals with the suppression of incendiary discharges from the DC eliminator by coupling the resistor and voltage supplied to electrode through several ignition tests.

25aD-4

“Prevention of an incendiary brush discharge by a charged cloud in grounded vessels”

Japan National Institute of Occupational Safety and Health

A. Ohsawa

This paper presents required conditions to prevent an incendiary brush discharge between a protrusion on a vessel wall and a charged cloud in the vessel grounded. To obtain the conditions in the charge density of the cloud and the maximum electric field on vessel wall, numerical calculations with different-sized protrusions and cylindrical vessels, which obtains the critical conditions to produce a discharge and also estimates its charge discharged and discharge energy, has been conducted. The protrusion less than 5 mm in the radius of its curvature leads to no incendiary discharge but in its radius exceeding it, an incendiary discharge is possible. In consequently, the obtained condition to reduce the ignition risk by an incendiary brush discharge in vessels less than $\approx 1.5 \times 10^5$ m$^3$ is that the maximum electric field at the vessel wall is less than 1 kV/cm.

25aD-5

“Effect of air flow on formation of a highly-charged particle cloud”

Faculty of Engineering, Yamagata University

Shin-ichi Migita, Kenji Toki, Toshiyuki Sugimoto and ○Yoshio Higashiyama

To form a high-density charged particle cloud ejected by strong air flow, relationship between the electrostatic property of charged particles in the cloud and ejecting velocity was investigated. Radial distribution of charge-to-mass ratio in the cloud showed that charged particles at the outer region of the cloud had larger charge-to-mass ratio and smaller size. Highly-charged small particles tend to move toward outside of the cloud by the electrostatic repulsion force and to adhere to the grounded object. Consequently although charge-to-mass ratio of the particles ejected at the air flow with a velocity of 16m/s was larger than that of 30m/s due to longer charging time, the electric field strength at the ground formed by the cloud was relatively smaller.

25aD-6

“Characteristics of Ignitability for Sprayed liquid due to Electrostatic Discharge”

Japan National Institute of Occupational Safety and Health

〇Kwang-Seok CHOI*, Mizuki YAMAGUMA and Atsushi OHSAWA

The minimum ignition energy (MIE) is a practical index to assess the ignition risk of flammable materials. This paper reports the results of experiments dealing with the MIE due to an electrostatic spark of a sprayed liquid under various conditions. As the samples, four kinds of the liquid - kerosene, n-decane, m-xylene, and styrene - were used. The liquid was pneumatically conveyed to the spray gun with an orifice a 1-mm internal diameter and automatically sprayed for 7 s to measure MIE. The spatial distribution of the MIE in spraying liquid under various conditions was also investigated in this study. The following results were obtained: (1) in the normal temperature range (0 ?C to 30 ?C), all sprayed liquids can be ignited by a spark with discharge energy below 10 mJ irrespective of their flash point. In particular, styrene was ignited with 4 mJ of an electrostatic spark; (2) an optimum region for ignition in a spraying liquid was observed, and it depended on the velocity, concentration, and particle size of the liquid.

25pB-1

“Simulation on Neutralizing Characteristic of AC Corona Discharge Air Ionizer”

The Polytechnic University

○Yuji TSUCHIYA , Kazuo OKANO

The relation between operating conditions and performance of AC corona discharge air ionizer are investigated by computer simulation. The discharge frequency was chosen as the operating conditions. Distributions of charged particle densities and electricfield that are the most important factor for estimating the neutralizing speed and EMI characteristics of the ionizer were chosen as the ionizer’s performance. The simulated results were compared with experimental results. The neutralizing speed slightly depended on the discharge frequency. The electric field decreases with increasing frequency.

25pB-2

“Ultra low-potential elimination by AC Corona Ionizer”

Faculty of Science and Technology Tokyo University of Science

Haruki Sasai

Various corona ionizers are widely used in industry for manufacturing electronic devices in order to prevent electrostatic hazard. However these ionizers could not eliminate charged objects perfectly because of unbalance of positive and negative ions generated by corona discharge. In this paper, for the purpose of low-potential elimination, some experiments are carried out. Concerning to the fluctuation of applied AC voltage, DC bias voltage and air blow velocity.

25pB-3

“Corona discharge ionizer and application to neutralization of static surface charges”

＊Iwate University, ＊＊Hitachi Kokusai Electric

○Masaru OHTANI＊,Seiji MUKAIGAWA＊,Koichi TAKAKI＊,Tamiya FUJIWARA＊,　Takeshi ITO＊＊,Kazuyuki TOYODA＊＊,Unryu OGAWA＊＊

here have been serious problems caused by static charges in electrostatic discharge (ESD) sensitive devices. For its solution the ionizer has been used to neutralize static charges. However, we have as yet some subjects, for example, how to eliminate the charges on many devices for short time. Using a corona discharge ionizer we studied the electrification and neutralization of the charges on the wafer surfaces at N2 atmospheric pressure. In regard to removal of the surface charges, ion balance decreased from ±1kV to around -20V.

25pB-4

“Shielding performance of soft X-ray ionizer with shielding structure”

* Technical R&D Center, Techno Ryowa Ltd., ** Dept. of Ecological Engineering, Toyohashi University of Technology

○Masanori SUZUKI*，Tomokatsu SATO*，Hideaki MATSUHASHI* and Akira MIZUNO**

　　Recently, in semiconductor and LCD manufacturing processes, ionizers have been used that employ low energy X-rays of 3 to 9.5 keV　(soft X-rays), as the ionization source. However, when this ionizer is installed on a　manufacturing equipment, the equipment must be covered with shielding panel to shield the soft X-rays. In addition, this equipment requires safety measures to stop ionizer automatically, when a worker entered a shielding area by any chance. For those reasons, this type of ionizers are inconvenient. Therefore we have conducted the development of soft X-ray ionizer with shielding structure.

In the previous paper, we reported the results of investigation about the structural condition of shielding structure that consists of aluminum honeycomb and perforated plates. In this paper, we report about the structural condition of shielding structure that consists of small pipes. We confirmed that the leakage dose rate of the soft X-rays could be decreased to less than 1 µSv/hr while allowing the passage of enough ion pairs to eliminate the static electricity.

25pB-5

“Relaxation time for air ionization by Soft X-ray”

Ibaraki University 1,The Polytechnic University 2

○Masashi SAKUYAMA 1, Manabu TAKEUCHI 1, Ryuta YOSHINIO 2, Kazuo OKANO 2

Relaxation time for air ionization by soft X-ray was investigated based on the experimental result of the neutralizing characteristic of the jet air ionizer. The jet air ionizer is composed of a stainless steel pipe with an acryl window and a soft X-ray source. The flowing air was ionized by soft X-ray irradiated through the window. The neutralizing speed was measured by the charged plate monitor located at the outlet of the pipe. The relationship between the concentration of charged particle and the irradiation time was calculated by the experimental result to find out the relaxation time. Relaxation time for air ionization by soft X-ray was 12 ms.

25pD-1

“Patterning of nanoparticles on substrate by cluster iondeposition method”

Osaka Prefecture Univeisity, Department of chemical engineering

Hiroyuki Shirai, Motoaki Adachi

The cluster ion deposition method, in which cluster ions are produced from a source vapor by a corona discharge and deposited electrostatically on a substrate are used to arrange nanoparticle on the substrate and form uniformly and quickly a nanoparticle film with a large area. In experiments, a tetraethylorthosilicate(TEOS) is used as source vapor. For nanoparticle arrangement,SiO2 nanoparticle are selectively deposited on charge patterns illustrated by a contact charging method. For nanoparticle film deposition they form uniform films with the density of 1.00e10 cm-2 and the area of 14mm×14mm.

25pD-2

“A Study on discharge current and radiation noise of ESD from charged metal”

Department of Electrical Engineering, Tokyo University of Science

○Takahiro YOSHIDA , Atsushi SUMIDA and Noriaki MASUI

In this study, we measure the discharge current and the radiation noise of electrostatic discharge from charged metal synchronously. In the measurement of radiation noise, three mono-pole antennas are set in vertical, horizontal, and 45 degree. When the discharge current has single peak, the high frequency component around 700MHz-900MHz appears on the wavefront of the discharge current and radiation noise. When the discharge current has 2 peaks, frequency component of discharge current and radiation noise are around 200MHz. The amount of charge including radiation noise is equal between positive discharge and negative discharge. In positive discharge, the amplitude of radiation noise from the antenna set in horizontal is a maximum. In contrast, in negative discharge, the minimum amplitude of radiation noise is obtained from the antenna set in horizontal.

25pD-3

“Technology of Charging Control in Conveyance Manufacturing Process of Electronic Machinery on the Basis of the Effective Work Function”

Mitsubishi Electric Corp. Advanced Technology R&D Center

Hiroyoshi KITABAYASHI

Recently in manufacturing process of electronic machinery, the contact electrification of machinery is probable to cause the ESD to the semiconductor devices in the electronic machinery. In particular, this phenomenon can be confirmed in conveyance process of machinery manufacturing. Therefore it is necessary to understand the charging mechanism and to provide the countermeasures to the contact of electrification. It is known that contact electrification is related to the effective work function of materials. When materials with equal work function came in contact, there is little charge generated between materials. So we measured the effective work function of the materials which are used for the machinery and suggested the material of the apparatus which was not charged even if the machinery was contacted.

25pD-4

“Effects of the relative humidity on ESD from the charged metal”

Department of Electrical Engineering, Tokyo University of Science

○Atsushi SUMIDA, Takahiro YOSHIDA and Noriaki MASUI

In this paper, by using spherical electrodes (20mm in diameter), effect of applied voltage and relative humidity on the short air gap discharge is discussed experimentally. The humidity of the discharge space is 2%RH and 40%RH. Applied voltage is from +2kV to +9kV. Material of the electrode iscopper and brass plated with chromium. Earth electrode approaches the high voltage electrode at 0.4mm/s and spark discharge is occurred. When the humidity is 2%RH, the gap length of discharge inception is shorter than that in 40%RH. The waveform of discharge current depends only on the breakdown field strength. When the applied voltage is from 2kV to 4kV, discharge current having almost the same waveforms are obtained for the change in the relative humidity.

25pD-5

“Relationship between waveforms of discharge current from the charged human body and discharge pattern on the fingertip”

Department of Electrical Engineering, Tokyo University of Science

○Hiroyuki TAKAZAWA , Takahiro YOSHIDA and Noriaki MASUI

In this paper, the relationship between waveforms of discharge current from the charged human body and the discharge channel appeared between fingertip and earth electrode is discussed. The body potential is from ±2 kV to ±10 kV. When the applied voltage becomes low, the multiple discharge channels are appeared between fingertip and the earth electrode. These channels are appeared at the very high probability, when applied voltage is lower then 4kV. When the applied voltage is higher than 5kV, single discharge channel is appeared in most case. The summary of the mechanism of the generation of these channels is examined.

25aA-1

“Elastic Control of piezoelectric PZT Ceramics”

Grad. Sch. of Eng., Kansai Univ., Imoto Mech. Eng＊., Kobayashi Inst. of Phys. & Chem＊＊

Komei TAHARA, Hiroaki UEDA, Kenji IMOTO＊, Munehiro DATE＊＊, Eiichi FUKADA＊＊, Yoshiro TAJITSU

We report a novel elasticity control technique for piezoelectric lead zirconate titanate (PZT) ceramics using an electric circuit that behaves as a “negative capacitor” (hereafter referred to as a negative-capacitance circuit) for application to the sound shielding technology. A feature of this technology using an optimized negative-capacitance circuit is effective sound attenuation regardless of the PZT ceramic type or frequency ranges of the noise. In this experiment, we prepared three types of PZT ceramic with different dielectric and piezoelectric characteristics. We improved the circuit constants of negative-capacitance circuits for the three kinds of PZT ceramic with different physical properties. We measured the transmission loss attenuation factors of the three types of PZT ceramic in the frequency range from 1 kHz to 100 kHz. We found that the transmission loss attenuation factors in of all three types of ceramic were greater than 20 dB in the frequency range from 1 kHz to 100 kHz.

25aA-2

“Piezoelectricity of Chiral Polymeric Fibers”

Grad. Sch. of Eng., Kansai Univ.

Masahiro HONDA, Kazuto HAYASHI, Masayoshi KANASAKI, Yu MORIMOTO and Yoshiro TAJITSU

Chiral polymers have recently attracted attention as a polymer which exhibits a high shear piezoelectric constant. Chiral polymers are not ferroelectrics but piezoelectrics. Also, to realize piezoelectricity throughout the entire chiral polymeric fiber, the chiral polymeric fiber does not require poling treatment. On the other hand, the chiral polymeric fiber shows the very small piezoelectric constant. Its value is 1/100 or less compared with that of inorganic ferroelectrics and piezoelectrics. However, we succeeded in controlling the piezoelectric motion of the chiral polymeric fiber by applying dc voltage and ac voltage similar to a piezoelectric actuator.

25aA-3

“Nonlinear Permittivities in Potassium Salt Ionomers of Ethylene Copolymer.”

○*Technical Center, DuPont Mitsui Polychemicals Co., LTD.、

**Graduate School of Engineering, Kansai University

Nobuyuki Maki

We report the frequency spectra of complex linear and nonlinear permittivities of potassium ionomer films prepared from poly (ethylene-co-methacrylic acid) in the frequency range from 1 kHz to 1 MHz, at room temperature. A characteristic conduction relaxation phenomenon was observed in the spectra, which suggested the existence of different ion conduction mechanisms between the high and low-frequency regions. We also found that the ratio of linear to nonlinear conductivities calculated from nonlinear permittivities was closely related to the elementary process of ionic transport. Furthermore, the ratio obtained from nonlinear measurements allowed an estimate of the important parameters which characterized ionic transport in ion-conducting polymers, such as the hopping distance of ion or the size of a connected cluster of the site capable of the ion hopping, without the need for any additional assumptions in potassium ionomer films.

25aA-4

“Change in Charging Characteristics of Polymer Powder with Very Small Size”

Faculty of Science & Technology, Tokyo University of Science

○Yusuke KUDO, Takayoshi SAITO, Yuji MURATA

Change in characteristics of contact and frictional charging of polymer powders with very small size after treatment in O2 gas plasma was investigated. When the very small polymer powders were treated, the powder particles tend to adhere to electrodes and their treatment efficiency deteriorate. It was found that treatment efficiency could improve by applying DC bias voltage to GND electrode. Obtained surface charge density of the treated powder particles kepts constant regardless the diameter of the particles.

25aA-5

“Thermally Stimulated Surface Charge Decay easurements in Polymer Powder Layers”

Department of Electrical andElectronicEngineering,Ibaraki University

○Akihiro Suzuki　Manabu Takeuchi

Thermally stimulated charge decay (TSCD) measurements were carried out on polymer powders to investigate the charge traps. A polymer powder layer was formed in a metal sample holder, and its surface was corona charged, and the decay of the surface potential was recorded when increasing the temperature. A spherical acrylic powder (10m) was used in this study. It was confirmed that TSCD measurements give similar information concerning charge traps in polymers as TSC measurements. The corona charging time was changed from 5s to 100s. The corona charging for 30s was sufficient for filling all the traps by charge carriers. Heat treatments of the polymer powders changed TSCD spectra.

25aA-6

“Effect of crystal face on triboelectrification using a single crystal ice”

Hokkaido Univ. of Education

Hisashi Shio

25aA-7

“Charged fog generated by ultrasonic atomization of pure water”

Kanagawa Institute of Technology

Takahiro SATO Hirofumi SHIMOKAWA

This study examined the electrification quantity of the fog in doing ultrasonic atomization of pure water. In the water of lowpurity, the electrification fog in proportion to the induced voltage polarity arose. However, in the water of high purity, the electrification fog of the negative polarity arose without relating to applying the negative induced voltage. Especially, it was found that the negative charged fog arose, even if the induced voltage was not applied in the high-pure water. From this fact, when the purity of the water rises, the electric double layer which exists in air/water interface, seems to have firmly been formed.

This fact was supported from the measurement results in mixing the surfactant.

25pC-1

“Basic Experiment on Electrostatic Pesticide Spraying to Fruit Tree”

Electrical and Electronic Engineering, Tottori University

○Tomoya NISHIKAWA,Kazuya NISHIO,Ryo NISHIMURA,Katsumi NISHIMORI,Naganori ISHIHARA

We quantitatively measured the effectivity of electrostatic pesticide spraying. We sprayed the solution of edible dye in water to potted Japanese pear trees from a spray nozzle that high voltage (-50 kV) was applied. The nominal pumping pressure and rate of the spray are 2.7 atm (2735 hPa) and 4.48 cm3/s, respectively. The distance between the trees and the nozzle was 120 cm. We measured the volume of the water droplet on the pear leaves after spraying. In the case when the voltage was not applied to the nozzle, the 0.52% of the sprayed water adhered to the leaves. On the other hand, when -50 kV was applied to the nozzle, the adhesion rate was improved to 2.6%.

25pC-2

“Electrostatic potential of spray target coated by metallic spray”

*Yamagata university **Alpha techno-tool co. ltd.

Toshiyuki Sugimoto*, Noriyuki Shirahata*, Yoshio Higashiyama*, Koichi Takeda**

Spray charging of metallic paint has been investigated by measuring electrostatic potential of a spray target. The metallic paint was sprayed by a commercial air spray gun with and without Induction charging method. The potential of the sprayed plate was drastically increased up to + 4 kV without induction charging by the spray charging of the metallic paint. The electric current flowing through the spray gun was significantly small compared to the potential rise of the target. The result indicates that small spray particles are charged negatively and large particles are charged positively. Because the airflow including the paint particles is deflected by striking the target, small particles loose a chance of adhesion to the target. The large particles mainly adhere to the target, resulting in the positive potential rise. Negative dc high voltage to the spray gun could control the target potential due to the induction charging.

25pC-3

“A Discussion on Optimizing the Operation of the Atomized Electrostatic Powder Coating System”

*1 Zao Electrostatic System Laboratory, *2 Top Industries, Co., *3 I. P. D., Inc.,

Mitsuru MATSUI*1, Takashi TAKAHASHI*2 and Tsutomu ITO*3

This paper describes a discussion on optimizing the operation of the atomized electrostatic powder coating (APC) system by increasing the amount of the conveying air, which affects strongly to penetrating of powder inside recessed areas and electrostatic wrap effect. For most of the conventional coating systems, the conveying air of 80 l/min has been recommended as an empirical standard value. However, an experimental investigation using the APC system with a fine particle powder resulted in about 13% of increase in coating thickness, when the amount of the conveying air was increased from 80 l/min to 120 l/min. It can be considered that the increase in coating thickness is brought by intensifying the corona charging efficiency for powder particles due to the increase of the conveying air.

25pC-4

“Charging Characteristics of Coating Powders (�T)”

Department of Electrical andElectronicEngineering,Ibaraki University

○Ken-ichi Kanai, Takahiko Kurisaki, Manabu Takeuchi

Fundamental electric properties of coating powders, consisting mainly of polymers and pigments, were investigated to improve performance of electrostatic powder coating. Surface potential decay after corona charging were monitored in polymer coating powder layers. Apparent resistivities and charge to mass ratio q/m of polymer coating powders were also measured. The surface potential decay was faster in the normal polyester powder than the powder, which was not deposited on a substrate in the electrostatic powder coating. The charge to mass ratio was smaller in the powder not deposited on a substrate than the normal powder.

25pC-5

“Improvement of the Charging Process for High-speed Electrophotography(�U)”

Faculty of Science and Technology Tokyo University of Science

Daisuke YAMASHITA

This study concerns to the improvement of the charging system for high-speed electrophotography. For the purpose, the possibility of increasing charging speed was examined using a charging system with wire electrode. When the distance d of wire electrode and drum surface comes close to 3mm, corona current was 54μA/cm at surface potation of -800V, and the charging speed was 540PPM. The Charge distribution on the drum surface was also investigated.

25pC-6

“Fundamental Study on Electrostatic Demulsification Process of Small Volume W/O emulsion”

Toyohashi University of Technology

○Michihiko NAKANO，Akira MIZUNO

Water-in-oil (W/O) emulsion has been applied to biological and chemical reactions. We previously showed a new emulsification method using AC electric field that was suitable for the application of W/O emulsion. Because electrodes were placed outside of the vessel, a non-contact process was realized to avoid any contamination. In this paper, fundamental study on demulsification processes using electrostatics was described. We used small plastic tubes of 0.2 mL in volume. The electrodes were placed outside of the plastic tube. 0.2 mL of W/O emulsion in the vessel was demulsified by AC electric field through pear-chain formation of the droplets. Two electrode configurations were tested, with two different frequencies of AC voltage (60 and 17 kHz). Each experiment showed the AC electric field enabled to demulsify, however, it took more than 10 min. With higher frequency, the demulsification was more effective.

25pC-7

“Electrostatic Process in Liquid-Liquid System (II) -Resolution of W/O Emulsion by Bipolar Charging Method-”

Department of Electrical and Electronic Engineering，Oita University

Yusuke Seiji Seiji KANAZAWA, Yuusuke TAKAHASHI

Demulsification of W/O emulsion was studied by the injection of bipolar charged water droplets. One nozzle electrode with positive dc high voltage was produced positively charged water droplets, while other nozzle electrode with negative dc high voltage was produced negatively charged water droplets. The atomized water droplets with both polarities captured the suspended water droplet in the emulsion and then collide with each other. The aggregation droplets fell down due to the gravity as well as EHD flow effect, resulting in the separation of water and oil. The test liquid, which was prepared by the electrostatic atomization technique, was maintained a state of emulsion for longer time if no electric field was applied. When the bipolar charged droplets were injected into the test liquid, the emulsion with a dull color gradually became transparent as a time elapsed. The demulsification promoted until the water content became less than 0.04%.

25pC-8

“Positive Polarity Operation Characteristics of dc Wire-Non-Parallel Plate Type Electrohydrodynamic Gas Pumps”

＊McMaster University、＊＊Osaka City University、†Ariake National College of Technology

Ueno JUN＊,＊＊、Hiroaki TSUBONE＊.†、B. KOMEILI＊、Shigeyuki MINAMI＊＊、G. D. HARVEL＊、○Kuniko URASHIMA＊、J. S. CHANG＊

The effects of positive polarity applied voltage on velocity profile, pressure rise and volume flow rate for wire-non-parallel type EHD gas pump were experimentally investigated and analyzed by dimensionless parameters. The experiments were conducted at atmospheric pressure and room temperature, where air was used as the working fluid. Experimental results show that; (1) Depending on electrode position, the maximum gas velocity 1.3 m/s and volume flow rate 19.3 l/min were observed; (2) The volume flow rate, pressure drop and velocity increase with increasing applied dc voltage or EHD number.

25pC-9

“Miniaturization of a Stacked-type Electrostatic Actuator”

Tokyo Institute of Technology

○Tatsuro TAKSHIGE,　Yoshiyuki HATA,　Motoki TACHIIRI,　Keiji SANEYOSHI

We are developing a stacked-type electrostatic actuator that generates contractile force for purpose of the artificial muscle. This actuator is made of two ribbon-like films. We alternately fold the two films and fabricate the actuator just like a paper spring. The electrostatic force is inversely proportional to the square of the distance between two electrodes and proportional to the dimensions of the electrode, as this actuator has the condenser structure. Therefore, it is effective to miniaturize the films. And it result in producing more strong force. In this paper, we report fabrication of the film that the dimension of electrodes is as large as possible by etching. This method will be good to make more minute film. We fabricated the actuator using the films 0.7mm width, and drive it at 600V.

25pC-10

“Basic Research on Disk Type Corona Motors (�])”

*Sendai National College of Technology ，**Shishido Electrostatic, Ltd.

M. Hattori*, K. Takahashi*, S. Miura*,T. Oizumi*, and K. Izumi**

In our previous report, a multi-disk-type corona motor comprising a multi-DVDs (Digital Video Disk) rotor and a number of dual-printed circuit boards stator was proposed and tested for its torque-generating characteristics. Each stator board has 20 discharging electrodes and a partial slit to allow the rotor to be inserted and extracted without disassembly. To use the corona motor, an ozonic water generation system was constructed and tested, however, liquid ozone (ozonic water) density generated was very low and a higher density of gaseous ozone was needed. This time, an ozone density regulator was proposed and tested, which can conduct about one-tenth of the density of the gaseous ozone to the ozonic monitor, in order to blow higher density gaseous ozone into the ozonic water.

25pB-6

“A study of Si-MIS structure with a mixed SrTiO3−Al203 insulating layer”

Kazuo HATTORI*, Noriyuki Nakajima*, and Akira MIZUNO**

*Department of Electrical and Electronic Engineering, Toyohashi University of Technology, **Department of Ecological Engineering, Toyohashi University of Technology

Electronic devices such as DRAM and VLSI consist of Si metal-insulator-semiconductor （MIS）structures. As insulating layers, SiO21ayers have excellent electrical properties．As the memory cell areas decrease, thickness of the insulating layers should be decreased to form large capacitances. Strontium titanate

（SrTiO3）shows a high relative dielectric constant at room temperature. Accordingly, SrTiO3 layer is a very good candidate to form large capacitance instead of thin SiO2 1ayers．The purpose of this study is to fabricate Si-MIS structure with good electrical properties. Mixtures of SrTiO3 and Al203 are used to form

an insulating layer: The diffusion of A1203 into SrTiO3 1ayers is carried out to decrease the dissipation factor of SrTiO31ayers．The SrTiO3 powder was ground with ball mill until its grain size became less than l μm in diameter．The SrTiO3 powder was deposited on a p-type Silicon substrate using corona discharge. The

powder on the substrate was humidified by vapor of water and heated in a wet oxygen atmosphere at 900℃ for 3.5h. Aluminum was deposited on the SrTiO3 1ayer by vacuum evaporation as a starting material of Al203． The deposited Al was dissolved by vapor of nitric acid（HNO3）and heated in a wet oxygen atmosphere at 500℃ for l.5h to form Al203. The obtained Al203 was diffused into the SrTiO3 layer in a wet oxygen atmosphere at 800℃ for l.5h. After that，Al dots of l mm diameter were evaporated as a gate electrode. The thickness of the insulating layer thus obtained was approximately 400nm. The C-V characteristics were measured for the bias region from inversion（＋1V）to accumu1ation（−10V）in the frequency range 100 Hz〜1 MHz. The maximum of relative dielectric constants was10.7 at 100 Hz and the minimum of dissipation factors was 0.016 at 4 kHz. The hysteresis in the C-V curves at l MHz were measured with very slow speed: It took l.5h for the measurements. The hysteresis was found to be less than 0.15 V of an ion drift type. The surface-state densities were estimated by applying Terman method to the C-V curves at l MHz. The surface-state densities around the mid gap of Si were estimated to be in order of 1010eV-1cm-2. These results show that the fabricated Si-MIS structure with an insulating layer composed of SrTiO3 and Al203 has fairly good electrical properties.

25pB-7

“Numerical Simulation on Streamer Propagation in Nanosecond Pulse Corona Discharge Induced Nonthermal Plasma for Pollution Control”

Department of Mechanical Engineering, Osaka Prefecture University

Masaaki Okubo and Toshiaki Yamamoto

Numerical analyses are conducted on a nanosecond positive pulse dielectric barrier discharge-induced nonthermal plasma (NTP) for pollution control. In the numerical analysis, a commercial simulation software, CFD-ACE+ solver, is used. One-dimensional simulation results indicate that a streamer progressing from the positive electrode to the grounded one is well simulated. At the end of the pulse, the electron temperature and electron number density in the coaxial-type plasma reactor finally reach approximately 1.7 eV and 10^15 m-3, respectively. The radial electric field is almost constant in the plasma region. During the single pulse, the peak concentration of ozone is approximately 40 ppm near the surface of the glass barrier. Further, in the two-dimensional simulation result, the streamers propagation (1st and 2nd) can be simulated well numerically.

25pB-8

25pB-9

“Measurement of OH Radicals in Atmospheric Pressure Corona Discharge by Laser-Induced Fluorescence (II)”

* Department of Electrical and Electronic Engineering, Oita University ** Institute of Fluid Flow Machinery, Polish Academy of Sciences *** Department of Engineering Physics, McMaster University

Seiji Kanazawa*, Hiroto Tanaka*, Toshikazu OHKUBO*, Marek Kocik**，Jerzy Mizeraczyk**，Jen-Shih Chang***

The LIF measurement of the hydroxyl (OH) radicals in the reactor with a nozzle-to-plane electrode system having an electrode gap of 30mm was performed. The LIF signal in DC corona streamer discharge can be obtained with a properly adjusted timing of the ICCD camera taking into account of the time relationship between the regular streamer, probe laser, and laser-induced streamer. As a result, the ground-state OH radicals were observed during the steady-state positive streamer corona discharge. OH LIF signal was detected along the laser beam path not only in the discharge region but also outside of that region. The influence of ozone on the OH LIF signal was investigated experimentally.

25pB-10

“Fundamental Experiments on a Silent Discharge Reactor with Anodic Porous Alumina for Gas Treatment”

Department of Electrical and Electronic Engineering, Nippon Bunri University

Toshiyuki Kawasaki

The simultaneous treatment of gaseous pollutants and suspended particle matter (SPM) exhausted from a diesel engine is one of the most serious problems in our living environment. Non-thermal plasma skillfully combined with ceramics, for example DPF, is very attractive for the simultaneous treatment. In this study, we focused on the silent discharge plasma reactor used anodic porous alumina, which have many pores for collecting SPM, as a barrier.

A purity 99.99% Al sheet was electropolished under a constant current condition of 100mA/cm2 below 5℃ for 2.5min in a mixed solution of HClO4 and C2H5OH after a buffing. Then, the anodization of Al was carried out in 0.3M or 0.5M sulfuric acid under a constant voltage condition of 24V at about 4℃ or 20℃. Two anodic porous alumina prepared under the same condition were faced at the gap length of 1mm in air. 1kHz high voltage was applied between two anodic porous alumina using the Al substrate as electrodes. Maximum thickness of alumina film was about 120μm under the condition of 0.5M sulfuric acid at 20℃ for 5 hours. In this case, alumina breakdown voltage showed maximum value of 5kV, as a result uniform silent discharge plasma was not obtained. Various anodizing conditions will be studied in order to produce uniform silent discharge plasma.

25pB-11

“Experiment about NOx removal for comparing the direct plasma chemical hybrid process with the remote plasma chemical hybrid process”

Osaka Prefecture University

○Yuji FUKUMOTO＊，Shunji HARUNA＊＊，Hidekatsu FUJISHIMA＊, Tomoyuki

KUROKI＊, Masaaki OKUBO＊ and Toshiaki YAMAMOTO＊

Previous results have shown that the plasma-chemical hybrid process was effective for simultaneous removal of NOx, SOx and diesel particulate. In the present study, two types of plasma supplies, the direct oxidation method and the indirect plasma oxidation (air radical injection) method, were evaluated with regard to NO and NOx removal　efficiencies and applied power. The air radical injection method showed that both NO and NOx removal efficiencies were better than those of the direct oxidation method even at around 1/3 of applied power. Furthermore, performance parameters of NO oxidation were investigated. As a result, more than 80 % of NO removal efficiency was achieved when the ratio of air radical gas to exhaust gas was in the range of 20 %.

25pB-12

“Diesel NOx Reduction and Regeneration of Adsorbent Using N2 Nonthermal Plasma”

Environmental Protection Engineering Laboratory

Department of Mechanical Engineering, Osaka Prefecture University

○Keiichiro Yoshida, Masaaki Okubo, Tomoyuki Kuroki, Toshiaki Yamamoto

Comaprison of performances among various types of nonthermal plasma reactors was carried out in order to realize diesel emission aftertreatment system using our proposed nitrogen nonthermal plasma desorption. It was found that the surface discharge reactor and the packed-bed reactor have higher NOx reduction capabilities than the pulsed powered wire-cylinder reactor. It was suggested that low cost exhaust treatment system was possible by using AC power supply.It was also clarified that the pulse powered wire-cylinder reactor was the most effective reactor for regeneration of NO zeorite adsorbent of molecular sieve 13X.

25pB-13

“Study of NOx removal by low discharge voltage by using atmospheric micro plasma”

Shizuoka Univercity.

○Takeki Sugiyama, Kazuo Shimizu

An atmospheric micro plasma is generated in micro gap electrodes with dielectric barrier. With this micro gap electrodes, discharge voltage is only around 1 kV. Removal of simulated gas contains nitric oxide, and hydrocarbons is experimentally investigated. The types of investigated simulated gases are �@NO 100ppm, N2 baｌance, �ANO 100ppm, O2 5%, N2 baｌance, �BNO 100ppm, C3H8 500ppm, N2 baｌance and �CNO 100ppm, O2 5%, C3H8 500 ppm,N2 balance. When the gap length of 10 um, NOx removal of 30% are acheved.

25ｐB-14

“Effects of VOC Mixing on Energy Efficiency and Byproduct Distribution in VOC Decomposition with Nonthermal Plasma”

National Institute of Advanced Industrial Science and Technology (AIST)

Shigeru Futamura and Masami Sugasawa

Effects of VOC mixing on energy efficiency and byproduct distribution in the decomposition of methanol and dichloromethane or toluene were investigated with a ferroelectric packed-bed reactor. The magnitudes of energy efficiency and the reactor energy density giving optimum efficiencies were affected by the chemical structures of the above compounds, but optimum energy efficiencies were obtained at < 0.2 kJ/L for all of them. Energy efficiency generally increased with their initial concentrations. Addition of 5% O2 increased energy efficiency at lower reactor energy densities. VOC mixing effect on byproduct distribution was observed only in the decomposition of methanol and dichloromethane in N2, but, the concentrations of the byproducts drastically decreased on addition of 5 % O2.

25ｐB-15

“Screening of the Useful Catalysts For The Decomposition of VOCs Using Cycled System of Adsorption and Oxygen Plasma”

National Institute of Advanced Industrial Science and Technology (AIST)

H.H. Kim, A. Ogata, S. Futamura

In this work, comprehensive investigation was done on the oxygen content-dependent behavior of the various catalysts with respect to the decomposition of VOCs. The tested catalysts include TiO2, g-Al2O3, zeolites and several types of metal catalysts (Pt, Pd, Ag, Ni, Au) with different loading amount. Although there is difference in degree of the enhancement, the increased in oxygen content increased the decomposition of VOCs and the selectivity of CO2 as well for all tested catalysts. These strong oxygen content-dependent behavior were not observed with the nonthermal plasma alone or the thermal catalysis alone.

25pS-1

26aA-1

“The Space Charge Distribution Measurement of Antioxidant Addition Polyethylene Res”

*College of science and technology Nihon University **Junior college Nihon University

○Yoshikazu HOSHIMURA*， Shun KOBAYASHI*， Kiyoshi KINOSHITA**

We examined influence to space charge distribution of low density polyethylene by antioxidant addition. In addition, as examination of possibility of new electric materials by antioxidant addition, gathered it up about a change of crystal structure of a sample by the insulation characteristics and maltese cross observation of a sample by the insulation resistance measurement. Therefore it was assumed that we are the most important in oxidation mechanism of polyethylene resin and added the antioxidant which stopped an oxidation chain reaction effective. In addition, we added an antioxidant effective against it because there was a case to be oxidized from impurities to be included in materials. We are able to confirm an accumulation electric charge after heat-treating it in the sample which added an antioxidant. However, we cannot confirm accumulation of an electric charge after heat-treating it by additive-free PE. By this, we found an effect of the oxidation-resistant of PE by antioxidant addition PE.

26aA-2

“The study of the control over the electrostatic charging characteristics of polymer material by printing technique”

Denki Kagaku Kogyo K.K.＊、Department of Organic and Polymeric Materials, Tokyo Institute of Technology＊＊

○Masatoshi Kawata＊，＊＊、Teruaki Hayakawa＊＊、Masa-aki Kakimoto＊＊

We investigated the control over the electrostatic charging characteristics of polymer materials by printing technique.

26aA-3

“Control of Charging Characteristics of polymer by corona treatment”

Faculty of Science and Technology Tokyo University of Science

Minoru Ouchi

Charging characteristic of polyethylene film varies after treated by corona discharge toward negative polarity. Charge generated by contact and friction increase with the increase of electric energy density of corona discharge. charge density of LDPE firm treated by 53kJ/m2 corona became greatest and changed into about 19 times as range as that of non- treated sample. The influence of diameter of corona wire, and electric conditions are investigated.

26aA-4

“Apparatus of Measuring the Two Dimensional Distribution of Surface Charges with a Sample on an XY Axes Stage and a Surface Charge Distribution on a PMMA/PET”

*Graduate School of Engineering, Nagoya Institute of Technology, **Denki Kagaku Kogyo K.K.

○Yasuro HORI*, Makoto HONAGA*, Masatoshi KAWATA**, Takeshi YAMAKAWA* and Hitoshi HASEGAWA*

An apparatus of measuring the two dimensional distribution of surface charges has been constructed with a sample on an XY axes stage. All the system is controlled by an on-line computer. By using a probe electrode with 1.6 mm diameter, the two dimensional distribution of surface charges can be measured with a precision of 0.2 mm. This system assures that a line of 20 mm long can be measured within a 1.5 seconds and an area of 400 mm2 within 240 seconds with a precision of 0.2 mm x 0.2 mm by employing a newly designed pre-amplifier with an operational amplifier having a very low bias current (2 pA) and with a rather high input impedance (1.5 TΩ). By using this apparatus, a two dimensional distribution of surface charges has been observed on a PMMA/PET film which is made by printing PMMA on PET base film in the 1 mm x 1 mm checkered pattern. The surface of PMMA/PET film was charged by peeling off an acetate adhesive tape. The negative charges on PET portion and the positive charges on PMMA portion have been clearly observed as a 1 mm x 1 mm checkered pattern.

26aA-5

“Change in Characteristics of Photoelectric Emission after Irradiation of Thermoelectron and Charging Characteristics of Glass”

Faculty of Science & Technology, Tokyo University of Science

○Yusuke KUDO, Shunsuke NARUSE, Yuji MURATA

Electrification of glass causes various troubles in industry, however, the electrification mechanism of glass is not clarified. In previous study, it was found that there was a clear correlation between characteristics of contact and frictional charging and photoelectric emission. In this study, measurement of photoelectric emission after irradiation of thermoelectrons was carried out. After irradiation, the number of photoelectrons increases and the increase characteristics depend on the kinds of glasses. From the results, it was found that difference in density of acceptor affected the electrification characteristics of glass.

26aA-6

“Thermally stimulated current spectra of polypropylene with high molecular weight”

*Keio University, ** Science University of Tokyo, Faculty of Science and Technology

○Kazuo　IKEZAKI* and Yuji MURATA**

Open-circuit thermally stimulated current (TSC) spectra were observed at different charging voltages for high molecular weight polypropylene (HMW-PP) with and without a magnesium silicate (talc) additive. Electrode metal effect on these TSC spectra was also examined for Bi and Al. For these samples, maximum charge densities Q80 and Q120 were estimated for the charges trapped in the deep traps corresponding to their high temperature TSC bands (BH) above 80 oC and 120oC, respectively. The values of Q80 were estimated to be 9.7 x 10-4 [C/m2] for positively charged HMW-PP with Bi electrodes and more than 8.4 [C/m2] for negatively charged ones, respectively. These values are about 5~6 times larger than those of typical PP for film use. Although the value of Q80 for positively charged HMW-PP with Al electrodes was the same value of 9.7 x 10-4 [C/m2] as that of the samples with Bi electrodes, their TSC spectral shape strongly depended on metals used for electrodes. For talc-containing HMW-PP, the value of Q120 was about 3.0 x 10-4 [C/m2] irrespective of charging polarity and electrode metal, Bi and Al. These experimental results lead to a conclusion that adding of magnesium silicate into PP exclusively determines the charge trapping characteristics and the higher order structure.

26aA-7

“Thermally stimulated current spectra in ethylene-propylene random copolymer”

*Keio University, ** Science University of Tokyo, Faculty of Science and Technology

○Kazuo　IKEZAKI* and Yuji MURATA**

Thermally　stimulated current (TSC) spectra were observed for ethylene-propylene random co-polymer (ethylene content: 0.4 mol%) (EP) at different charging polarities and wide-ranging charging voltages. Observed TSC spectra showed two well-separated TSC bands appeared in the two temperature regions above and below 100oC. For positively charged EP samples, only a sharp TSC band B120 peaked at 120oC　appeared in the high temperature region above 100oC, while for the negatively charged EP and talc-containing EP samples the B120 band overlapped with another broad TSC band. TSC intensity of the negatively charged EP and talc-containing EP was anomalously large just before their melting. The maximum value of projected surface densities of the stable charges corresponding to the high temperature TSC band of EP and talc-containing EP samples were estimated to be 6.5 x 10-4 [C/�u], which is extremely large value comparing to that of typical polypropylene homo-polymer.

26aA-8

“Reversal TSC component in polypropylene open-circuit TSC spectra”

*Keio University, ** Science University of Tokyo, Faculty of Science and Technology

○Kazuo　IKEZAKI* and Yuji MURATA**

Anomalous current with reversal polarity was found in open-circuit TSC of polypropylene films. Intensity of this reversal current strongly depended on the charging polarity of the sample films. As a result, it was practically detected only in the positively charged samples. Appearance of the reversal current was suppressed by slight annealing of sample polypropylene at 60 oC for 10 min and also by addition of small amount of magnesium silicate in the same base polypropylene. This anomalous current was hypothetically explained by direct transport of charged water molecules desorbed from the sample surface across the air gap from the charged sample to the TSC observing electrode.

26aA-9

“Stability of PTFE and FEP Electrets”

.Graduate School of Engineering, Nagoya Institute of Technology.

○Takahiro KATO, Yusei YANAGIHARA and Yasuro HORI

The stability of electrets for PTFE films between 50μm and 500μm thick were investigated and FEP films between 25μm and 100μm thick were investigated. The films on the aluminum plate which is earthed, were charged by negative corona or positive corona, and voltages of the corona charged surface or of the back surface which is charged in opposite polarity to the corona were observed for long time. The PTFE of 500μm thick can not become an electret, because the polarity of the back surface was not opposite from the corona. The voltage of 300μm PTFE decayed very fast, but the 50μm PTFE film electret was stable. For FEP films, the stability of electrets was not dependent on the film thickness. The amount of deep traps was nearly equal between 25μm and 100μm FEP films, and the stable voltage was highest on the 100μm FEP.

26aA-10

“Control of Electrical Tree Generation in LDPE by Additive of Aromatic Compound”

Faculty of Education, Chiba University

○Yoshiaki Yamano and Masanori Jimbo

It was reported that the tree inception voltage for LDPE material is increased by the addition of anthracene (An). The increase in the inception voltage was considered to be resulting mainly from the two factors: the decrease in kinetic energy of free electron by the decrease in free volume in LDPE bulk, and absorption of the kinetic energy of electron carrier by the pi-electron excitation of An at the collision between the electron carrier and An molecule. This study focuses on the investigation into the effect of the second factor upon the increase in the inception volt-age using three kinds of aromatic compound; anthracene (An), azo-benzene (Az) and phthalocyanine (Pc). It was found that Az is effective to increase the inception voltage up to approximately 4 times higher than that for LDPE without additive. The increasing ratio for Az is almost the same as that for An. The addition of Pc, on the other hand, is not as effective as Az and An; the increase ratio for Pc is about the half of that for Az or An. The field in-duced luminescence due to the excitation of pi-electrons is detected in all of the materials with and without additive. The ranges of the luminescence spectrum due to the excitations for An and Az are 450nm-570nm, and the range for Pc is 770nm-900nm, which indicates that the energy absorption in the wave length range 320nm-500nm corresponds with the increase in the inception voltage. In the LDPE without additive, the induced luminescence is observed in the spectrum range 670nm-770nm, which is also observed in the luminescence of all the material with additive including Pc. It was confirmed that the luminescence in the spectrum range 670nm-770nm is unconcerned with the increase in the inception voltage by the addition of aromatic compounds.

26aC-1

“Collection of Aquatic Microorganisms by DEP”

Toba National College of Maritime Technology

Tomohito Ito

Dielectrophoresis (DEP) is a motion of dielectric particles caused by polarization effects in a non- uniform electric field. Experimental observation of small aquatic organisms in a non-uniform ac field is made. A cell with parallel plate stainless-steel electrodes, 0.2mm in thickness and 3mm in height, with a gap of 10mm which are separated by an insulating membrane with a small opening is prepared. Fresh-water plankton and other microorganisms are put into the cell and a voltage (1MHz; 〜500V) is applied between the electrodes. Plankton is trapped in the opening by a dielectrophoretic force of an ac constricted field. This result suggests that DEP is effective for collecting living small aquatic organisms.

26aC-2

“Plasma enhanced ammonia production at low temperature for urea SCR”

Toyohashi University of Technology＊, National University of Tucuman＊＊

○Yoshihiro IITSUKA＊, Hiroki YAMAUTHI＊, Kazunori TAKASHIMA＊, Shinji KATSURA＊, Graciela Prieto＊＊ and Akira MIZUNO＊

The purpose of this study is to enhance the reforming of urea to generate ammonia at temperatures below 400 K for urea SCR system. In this study, a dielectric barrier discharge type and packed bed type plasma reactor were investigated experimentally. The reactor was fed with humid gas and driven by pulsed high voltage at 400 K. The plasma significantly enhanced the reforming of urea. The packed bed type plasma reactor was more efficient than the barrier type plasma reactor.

26aC-3

“Evaluation of Energy Efficiency in CO2 Reforming of Aliphatic Hydrocarbons Using Nonthermal Plasma”

National Institute of Advanced Industrial Science and Technology (AIST)

Masami Sugasawa and Shigeru Futamura

CO2 reforming of methane (CH4) and propane (C3H8) were performed with a silent discharge plasma reactor (SDR) and a ferroelectric packed-bed reactor (FPR). Reactor performance was evaluated in terms of energy efficiencies for the decomposition of the substrates and production of H2 and CO. CH4 and C3H8 were reformed in SDR in the order of 1016 molecules/J at 298 K. The energy efficiencies for the decomposition of these hydrocarbons increased with their initial concentrations, but decreased with an increase in reactor energy density (RED). A positive temperature effect was observed only at low REDs at 298 and 433 K in SDR. In the reforming of CH4 at 298 K, comparable reactor performances were obtained for SDR and FPR.

26aC-4

“Development of textile electrode for PEF inactivation”

＊Dept. Biological and Chemical Emg., Gunma University，＊＊Textile Research Institute of Gunma

○Kana UEDA＊，Nobuyoshi KITAJIMA＊＊，Takayuki OHSHIMA＊，Masayuki SATO＊

Recently, a food original flesh flavor and taste is demanded from consumers. Though thermal sterilizing method has been widely used in food industry to inactivate microorganism, it would cause the loss of original food flavor and taste. We have been studying PEF sterilization technique, which bases on the destruction of biological membrane due to applying pulsed electric field. In this study we report a novel treatment system based on the textile electrode, combination of polyester thread and 0.2 mmf tungsten wire. The efficiency of PEF sterilization was depended on the applied voltage and the conductivity of the target solutions. Higher efficiency of PEF sterilization could be achieved with 7 kV of applied voltage, and lower solution conductivity.

26aC-5

“Enhancement of hand cleaning by charged disinfectant mist”

＊Dept. Biological and Chemical Emg., Gunma University，＊＊College of Indust., Nihon University

Takayuki OHSHIMA*, Seigo MIYASHITA*, Takuo KOGURE*, Tomoo NAKANE** and Masayuki SATO*

Effectiveness of liquid disinfectant mist generated by ultrasonic humidifier was studied for hand cleaning. 1 % CGH / 61 % ethanol was most effective to achieve efficient inactivation of Escherichia coli cells on the surface of agar medium plate. The mist of liquid disinfectant was introduced to the region of corona discharge with applying 5 or 15 kV dc. The charged mist efficiently attached to the surface of rounded agar medium plate when DC voltage was 10 kV. However, excess DC voltage, 15 kV in this study, resulted in the decrease of mist amount attached on the target. Although the time for sterilizing bacteria on agar medium plate without DC corona was seven minutes, it shortened to one minute with DC corona. We also examined the actual use for hand cleaning, and the enhancement of inactivating bacteria was confirmed in our hand cleaning system.

26aC-6

“Metabolism Activity Monitoring of Eschericia coli Using Dielectrophoretic Impedance Measurement Method”

Entest Japan，Inc.＊，　Tokyo Metropolitan Univ.＊＊

○Takaharu ENJOJI＊,＊＊,　 Eri AMAKO＊＊,　 Satoshi UCHIDA＊＊ and 　Fumiyoshi TOCHIKUBO＊＊

In the present work we evaluated a difference of metabolism activity of Eschericia coli （E. coli） which was given experimentally a heat-treatment stress by using an interdigitated microelectrode array and the dielectrophoretic impedance measurement (DEPIM) method. Conductance change (ΔG) measurements by DEPIM method were performed under two different frequency conditions (100 kHz and 1.0 MHz). For stress which stems from various heat-treatments, each ΔG of E. coli differed widely in 100 kHz frequency tests. However, each ΔG was almost equivalent in 1.0 MHz frequency tests except under high temperature stress condition (353.15K). It is demonstrated that conductivity of E. coli would be changed by heat-treatments stress compare with permittivity. These results suggest that DEPIM method with the interdigitated microelectrode array is effective in monitoring the metabolism activity of microorganism in real-time.

26aC-7

“Sterilization of tubes using low pressure pulsed discharge”

Department of Ecological Engineering, Toyohashi University of Technology

Isamu AMANO

In a medical field, sterilization is one of the most important processes for guaranteeing safety of services becouse infectious disease can be caused by incomplete sterilization. This is sometimes a problem with a catheter. We studied a plasma sterilization method for a catheter. A new type of low pressure plasma was examined in order to sterilize the inner wall of the tube effectively. Sterilization effect of discharge plasma on Bacillus Subtilis spores was investigated using low pressure pulsed discharge plasma.

26aC-8

“Sterilization mechanism by a low temperature plasma flow using microwave discharge at atmospheric pressure”

Institute of Fluid Science, Tohoku University, **Faculty of Engineering, Shizuoka Univ., ***Graduate School of Engineering, Tohoku University (1Presently, NTT East), ****Adtec Plasma Technology, **** Toyo Advanced Technologies

Takehiko Sato*, Takashi Miyahara**, Shiroh Ochiai***, Akiko Doi***,1, Takuya Urayama****, Tatsuyuki Nakatani*****

Sterilization mechanism of Escherichia coli by a low-temperature plasma flow at atmospheric pressure was clarified by analyzing the surviving cells and the potassium leakage of cytoplasmic material using ICP-MS. E. coli can be sterilized by the argon plasma flow under an exposure temperature of 383 K though the heated argon gas is not effective to sterilize them at 383 K. Sterilization effect of an ultraviolet emission from the plasma source is also obtained. Inactivation of E. coli results from the destructions of the cytoplasmic membrane under plasma exposure and the destruction of nucleic acids by exposure to ultraviolet radiation from the plasma source.

26aC-9

“Sterilization using discharge that uses dielectric barrier discharge together with surface discharge”

Toyohashi University of Technology* National University Corporation Gunma University**

〇Masakazu TANINO*, Kazunori TAKASHIMA*, Shinji KATSURA** and Akira MIZUNO*

We have developed a new plasma method having advantages of low temperature operation, time-saving and non-toxicity over the conventional methods, such as dry heat, steam autoclave, γ-ray irradiation and ethylene oxide (EtO) gas. Dielectric barrier discharge (DBD) with long gap can be generated under atmospheric pressure by combining DBD and surface discharge. The effect of sterilization against Bacillus subtilis was investigated under wet conditions. The long gap discharge with DBD and surface discharge showed the same high efficiency as that of the conventional short gap DBD plasma.

26aC-10

“Sterilizing of Escherichia coli by charged naodroplets”

Osaka Prefecture Univeisity, Department of chemical engineering*

Osaka Prefecture Univeisity, Department of biological science**

Kiyoko Mizota*, Motoaki Adachi*, Masakazu Furuta**

The charged nanodroplets were generated from H2O, C2H5OH, CH3COOH and Essential oil by the High-Pressure Ionizer and their size distributions were measured by Differential Mobility Analyzer/ Faraday Cup/ Electrometer systems. These vapor formed charged nanodroplets with sizes at 0.8-3nm. Bactericidal effects of negatively charged H2O nanodroplets for Escherichia coli XL1-Blue were studied by a colony count. The culture medium in which E.coli were planted were exposed to charged H2O nanodroplets and incubated at 37℃ for 24h. Survival rates were obtained by counting colonies and made it quantitatively clear that charged H2O nanodroplets have the ability to kill E.coli. In order to investigate mechanisms of the prevention of colony growth, the growths of E.coli after the exposure were measured by a calorimetry. The result indicated that charged nanodroplets have both the microbiocidal effect and microbiostatic effect against E.coli.

26aB-1

“Treatment of trichloroethylene by aerification using SPCP reactor”

Faculty of Engineering, Soka University

○Soshi WATANABE, Junichi IDA, Tatsushi MATSUYAMA, Hideo YAMAMOTO

We developed a new aerator for water treatment in which a ceramic filter and SPCP (Surface corona discharge induced Plasma Chemical Process) were combined. Since the system can produce oxygen radicals such as ozone as small bubbles in water, it is expected that the system can be applied for the treatment of polluted water. In this study, a feasibility and performance of the reactor for the decomposition of TCE (trichloroethylene) as a model pollutant in solution was investigated. Generally, the rate of VOC elimination follow pseudo first order kinetics and can be represented by contributions due to volatilization and oxidation. However, the rate of TCE elimination was not first-order in this study. The rate was accelerated as the reaction proceeded and the tendency was more obvious at higher discharge power. The results may be due to the promotion of volatilization and oxidation induced by the heat of discharge. It was also confirmed that the ozone production efficiency was higher at lower temperature of the solution. In general, ozone production efficiency decreases with an increase of temperature. Therefore, the result suggests that if the solution is cooled down, it absorbs the heat from the discharge and reduce the decrease of ozone production efficiency.

26aB-2

“Acetaldehyde removal by combining discharge plasma and water film”

Toyohashi University of Technology

Tomo NAITO

Recently, removal of Volatile Organic Compounds (VOCs) has been of great concern. Utilization of discharge plasma is one of the novel and effective methods. It is necessary to improve energy efficiency for practical use. In this study, the removal of acetaldehyde was studied using a pulsed corona discharge reactor coupled with bubble or wet absorbent. In the bubble-plasma reactor, acetaldehyde removal was 70%. The wire-to-cylinder type corona discharge reactor equipped with a wet wall showed the maximum acetaldehyde removal rate about 100% by positive pulsed high voltage application.

26aB-3

“Oxidation of Intermediate Products from Xylene in Air using TiO2 and Ag/TiO2 under Electron Beam Irradiation”

Japan Atomic Energy Agency＊＊、Saitama Institute of Technology＊

○Teruyuki HAKODA＊、 Akihiko SHIMADA＊、 Kanae MATSUMOTO＊＊、Takuji KOJIMA＊

Oxidation of xylene and oxidation-resistant intermediate products was studied by use of 0-10%w Ag/TiO2 under electron beam irradiation. The enhancement of production of CO2, as a final oxidation product from xylene, with suppression of the formation of CO was observed when TiO2 and Ag/TiO2 was in the vicinity of irradiation space. Addition of higher than 5%w Ag on TiO2 was useful as Ag/TiO2.

26aB-4

“Temperature Dependence of Toluene Decomposition by Synergistic Effect of Discharge and Catalyst”

*Toshiba Corporation, **National Institute of Advanced Industrial Science and Technology (AIST), ***Toshiba IT & Control Systems Corporation

○Kazuo HAYASHI*, Hiroyuki YASUI*, Motofumi TANAKA*, Hisahiro EINAGA**, Shigeru FUTAMURA**, Satoshi KURITA***, Kenichi Aoyagi***

Experiments were carried out to study the synergistic effect of discharge and manganese dioxide on the toluene decomposition. The toluene removal performance was the best at the room temperature, and declined as the temperature increased. Toluene was completely oxidized to CO and CO2 at > 100℃.

26aB-5

“Study of Indoor Air Purification by Using Micro Plasma”

Innovative Joint Research Center, Shizuoka University

Manisha Nishamani L.S

A pair of electrodes, covered with dielectric barrier, is developed to generate atmospheric micro plasma and its characteristics are examined. Discharge gap is set to less than 100um and observed discharge voltage is around 1kV. Indoor air pollutants such as formaldehyde is reduced via oxidation by ozone, generated though the electrodes. Higher ozone concentration is obtained and formaldehyde concentration is reduced successfully with low discharge power. The developed electrodes remove indoor pollutants under low energy consumption and low discharges voltage. Byproducts are confirmed by FTIR and HPLC.

26aB-6

“Toluene Concentration Using Nonthermal Plasma- Optimum of Plasma Desorption -”

Department of Mechanical Engineering, Osaka Prefecture University

:○Tomoyuki KUROKI, Ryouhei KAWABATA, Masaaki OKUBO and Toshiaki YAMAMOTO

The cost effective control of volatile organic compounds (VOCs) was　mandated to meet the stringent regulations. The conventional incineration process is inefficient and not economical to treat low concentration VOCs. As for more practical and economical VOCs removal process, toluene, which is one of the most popular VOCs, was used and the optimization of plasma desorption was researched. As the results, more than 30 times of toluene concentration with 1/60 of the flow rate was achieved. The repeating adsorption and plasma desorption were conducted and the effectiveness of plasma desorption was demonstrated.

26aB-7

“Ozone production efficiency using dielectric barrier discharge driven by pulse generator”

Iwate University*, Sawafuji Electric Co., LTD.**

〇Koichi TAKAKI*, Taiki SATO *, Kaname ARIMA*, Seiji MUKAIGAWA*,

Tamiya FUJIWARA*, Tomonori MIURA **

An experimental study on ozone generation using pulse voltage driven dielectric barrier discharge (DBD) plasma reactor is carried out to clarify an influence of duty factor of repetitive pulse voltage on ozone generation. A square waveform of 10 kV applied voltage was generated using a pulse modulator. IGBT switches were employed to generate the square pulse with 1 kHz in pulse repetition rate. The output voltages of the power supply were applied to the multipoint electrode DBD reactor. The ozone yield is around 100 g/kWh at several thousands ppm ozone generation in all cases. The yield slightly decreases with increasing ozone concentration. The ozone yield is almost independent of the pulse duty factor of square applied voltage under the present experimental condition.

26aB-8

“CO oxidation using the combined process of nonthermal plasma and nanometer-sized gold catalyst”

National Institute of Advanced Industrial Science and Technology (AIST)

H.H. Kim, S. Tsubota, M. Date, A. Ogata, S. Futamura