Abstract of All Papers Presented to 2005 Annual Meeting of The Institute of Electrostatics Japan

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

5aA-1

“Relation between Charging Characteristics of Plasma Treated Polyethylene and Treatment Gas and Power Supply Frequency”

Faculty of Science and Technology Tokyo University of Science

Minoru Ouchi

Plasma treatment is very effective to improve the characteristics of contact and frictional charging of polymeric materials. Charging characteristics of Low-density polyethylene (LDPE) film treated by Ar and N2 plasma did not seem to depend on power supply frequency from 400kHz to 800kHz. The charging characteristics of the sample treated by Ar plasma (600kHz) was improved toward positive polarity. From the result of ESCA analysis, it was cleared that quantity of introduced oxygen decreased and that quantity of introduced nitrogen.

5aA-2

“Effect of tensile stress on magnetic properties of Iron Nitride Foils by Nitrogen Plasma Irradiation Method”

College of Industrial Technology,Nihon University

Akira Masuda

Iron nitride foils were prepared by plasma irradiation method with tensile stress in the atmosphere of N2+30%H2 mixture gases using iron foils of 20μm thickness as raw material. According to Mössbauer spectroscopic analyses and XRD, the volume fraction of α” -Fe16N2 was calculated about 40% and 42%, respectively. Judging from Mössbauer spectroscopic analyses results, the saturation magnetization value of the α” -Fe16N2 agreed well with the experimental value measured by VSM and XRD. It was revealed that the saturation magnetization of α”-Fe16N2 prepared by nitrogen plasma irradiation method with the tensile stress was almost the same as that of massive α-Fe(Ms=2.74×10-4Wb・m/kg).

5aA-3

“Effect of volume between electrodes on Change in Charging Characteristics of Polymer powder by plasma treatment”

Faculty of Science and Technology Tokyo University of Science

Takayoshi Saito

The characteristic changes of contact and frictional charging of polymer powders after treatment in O2 gas plasma were investigated. It was known that the specific charge increases with the electrode diameter at a constant power．For a different electrode diameter，power density in the vicinity of inner wall of the treatment bottle is a measure of the plasma effect．Using fine spherical particles, the surface charge density was compared with that of toner.

5aA-4

“Space charge creation in polymeric insulating materials”

*Chiba Institute of Technology, **National Institute of Information and Communications Technology

○Atsushi Taya*、Satoru Komiya*、Yoshiya Haraguti*、Masato Ishida*、Yasuo Sekii*、Takashi Maeno**

In order to study the effect of moisture on the creation of negative hetero-charge in LDPE, XLPE and EPR, the charge profiles of

hetero-charges in LDPE, XLPE and EPR samples containing moisture were measured after they were soaked in acetophenone. It was confirmed that magnitude of charge densities of negative hetero-charge in those materials were proportional to the moisture contents. In addition, the influence of antioxidant on the creation of negative hetero-charge was also inoestigated. It was discovered that sulfur containing phenolic antioxidant and sulfur type antioxidant is responsible for the creation of negative hetero-charge in XLPE insulation. The mechanism of negative hetero-charge creation in these polymeric materials was also examined.

5aA-5

“Effect of Residual O2 Gas on Change in Contact and Frictional Charging Characteristics of Low-Density Polyethylene by N2 Plasma Treatment”

Faculty of Science and Technology Tokyo University of Science

Hideaki Tanaka

The charging characteristics of low-density polyethylene (LDPE) films were measured after N2 plasma treatment using different vacuum conditions before replacing gases from the air to N2 in a plasma chamber. After plasma treatment, the surface of LDPE film showed a positive or negative charging tendency when contacted with copper beads depending on the degree of vacuum before gas replacement. The results obtained were based on the results analyzed by using ESCA analysis. It was found that LDPE after plasma treatment in N2 in gas tends to generate a positive charge when contacted with copper beads, but its charging characteristics is affected by a very small quantity of O2 in N2 gas, which remained in the vacuum chamber before introducing N2 gas.

5aA-6

“Measurement of flow electrification in dielectric liquid flows through metal channels”

The Graduate School of Natural Science and Technology, Okayama University

○Satoshi TAKAHASHI*, Shouxin ZHU*, Seiichi WASHIO*, Masao TAKAHASHI**

In this paper, flow electrification in mineral oil through different shapes of channels made of metals such as pipes and holes in disks is measured. The current detected from the metal wall instantaneously rose to a peak value at the very beginning of the flow, exponentially decreased until it leveled off with time and approached a constant value. Once the flow occurs, charges are not only generated at the oil-metal interface but also are relaxed from one to the other, resulting in the decrease of detectable electrification. When the constant current values after the electrification leveled off were divided by the contact area in the channel, and were plotted against the time for the oil to pass through the channel, it turned out that all the ratios obtained for different flow rates and different channels approximately fell on the same curve which approached zero as the time became large.

5pA-1

“Initial surface potential dependence of thermally stimulated current spectra　for nucleating agent-containing high molecular weight polypropylene films”

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

〇Kazuo IKEZAKI＊ and Yuji MURATA＊＊

Thermally stimulated current (TSC) spectra were observed for high molecular weight polypropylene films containing a nucleating agent. Generally, two TSC bands were observed in these TSC spectra: a low temperature band BL and a high temperature band BH. For films charged to low initial surface potentials, only the BH band appeared. While, with increasing their initial surface potentials, the BL band also appeared and its intensity increased. As for the BH band intensity, anomalous behavior was observed: the intensity of the BH band increased at first with increasing the surface potential of the sample films, temporally decreased at the initial surface potentials of 700 volts, and then attained to a saturated value after slightly increased. Further, this intensity decreased again at the initial surface potential of 1.5 KV. From the saturated value of the intensity for the BH band, a projected surface density of deep charge trap sites for this band was estimated to be 1.9×1015 (1/m2). The observed transitional decrease in the BH band intensity suggests charge redistribution between the charge traps responsible for BH and BL bands, which leads to so-called crossover of the surface potentials found in many polymers. Mechanism for the anomalous phenomenon, however, is not clear yet.

5pA-2

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

Graduate School of Ibaraki University

○Takao Sugihara, Manabu Takeuchi

Thermally stimulated charge decay (TSCD) measurements were carried out on coating polymer powders to investigate the charge traps in polymers. 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. It was confirmed that TSCD measurements give similar information concerning charge traps in polymers as TSC measurements. There was no difference in TSCD curves between corona charging and tribo charging except for the charge quantity. Heat treatments of the polymer powders decreased charge trap density.

5pA-3

“Derivation of Intrinsic Thermally Stimulated Current Spectra　for Polymeric Powder samples”

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

〇Kazuo IKEZAKI＊ and Yuji MURATA＊＊

For polymeric powder samples, we proposed a general method to obtain intrinsic thermally stimulated current (TSC) spectra, ITSC, from which any effect of change in sample thickness during TSC observation was eliminated. The method utilizes a current signal Iobs, experimentally obtained from current TSD with an air gap or a voltage signal Vobs, from charge TSD in open-circuit, and sample thickness d for powder samples and relative dielectric constant εr of sample polymers . In both cases using Iobs or Vobs, derivation of ITSC is executed by an approximation of iteration. As a trial, we applied this method to a binder resin of toner for copiers and also to a powder paint for electrostatic power coating using actually observed Iobs and d, and assumed　εr for these polymers. For the binder resin, the intrinsic TSC, ITSC was obtained by iteration within 5times, and the obtained spectrum was found to reflect much more correctly the charge retention property of the resin than the actually observed Iobs. While for the powder paint, the ITSC (2) obtained after 2 times iteration was almost the same as the experimentally observed Iobs in their spectra shape.

5pA-4

“Influence of antioxidants on electrical

conduction in XLPE”

Chiba Institute of Technology

○Iori ENDO ， Manabu GOSYOWAKI , Kazuya YOSHIZUMI , Hiroto NAKAJIMA, Kazuo NOGUCHI , Ushio KAWABE , Yasuo SEKII

In order to study the effect of antioxidant on electrical conduction under DC voltage stress, the conduction currents in XLPE samples containing phenolic and sulfur type antioxidant were measured. It was discovered that the conduction current in XLPE insulation containing antioxidant is smaller than the current flowing XLPE containing no antioxidant. In XLPE insulation containing sulfur type antioxidant smaller current is found to flow than the current in XLPE containing phenolic antioxidant. It was found also that the magnitude of conduction current flowing XLPE containing sulfur type antioxidant is influenced by the content of added antioxidant. The added antioxidant in XLPE insulation is presumed to be traps for charges in XLPE insulation.

5pA-5

“The negative corona discharge from water droplet on insulation plate”

Kanagawa Institute of Technology

Daisuke Kogure

The corona discharge is generated from the raindrop which adhered on the insulator. It is considered that this corona discharge degrade insulation performance and water repellency of the insulator. Authors carried out the simulation of corona discharge from the water droplet on the insulator. This report examined the negative corona discharge from water droplet on insulation plate. It was found that distinctive discharge was generated from the water droplet on insulation plate. In addition, this distinctive discharge received the effect of the purity of the water droplet. From the result, relaxation time seems to be closely related to the negative corona discharge on insulation plate.

5pA-6

“Discharge Characteristics in Atmospheric Air Measured by Using Carbon Nanotube-Deposited Electrodes Fabricated by Electrophoresis”

Graduate School of Information Science and Electrical Engineering, Kyushu University

Nobutaka NAKAGAWA, Kiminobu IMASAKA, ○Junya SUEHIRO and Masanori HARA

Carbon nanotube can produce high electric field at the tip due to the high aspect ratio. Because of this feature, the carbon nanotube can be applicable to field emission electron source in vacuum with lower operating voltage or power consumption. In this study, effects of carbon nanotube on discharge characteristics in atmospheric air were investigated. Multi-wall carbon nanotubes (MWCNTs) were deposited on anode surface by electrophoresis under dc electric field. The discharge onset voltage of the MWCNT-covered electrode gap was lower than that of the bare metal electrode gap by 50% at most. This seem to be due to enhanced ionization of gas molecules under higher electric fields formed around the MWCNT tips. It was also found that the MWCNT-covered electrode gap sometimes were short-circuited before the air gap discharge onset at the electrode potential lower than 100V. The MWCNTs lifted by the electric field may be responsible for this peculiar phenomenon.

5pA-7

“Discharge Behavior in a High-Intensity Acoustic Standing Wave Field: Investigations from the Viewpoint of Precursor Discharge Phenomenon”

College of Indust. Tech., Nihon Univ.

○Tomoo NAKANE, Masahiko ITO, Taichi MURAKAMI, Mai HASHIMOTO, Takeshi MIYAJIMA and Tetsuro OTSUKA

The authors reported that when a discharge is produced in a high-intensity acoustic field, luminous part is spread wider due to the vibrations of gaseous medium. However, the detailed explanations of this phenomenon have not yet been done. In this study, the influence of the sound wave on the spark discharge was discussed on the basis of the precursor discharges that occurred before main spark discharges. As a result, it was found that the peak values of current waveform for the precursor discharge were changed by the sound wave irradiations.

5pA-8

“AC Corona Discharge at a Floated Wire Particle under the Condition of High

Relative Humidity”

Faculty of Engineering, Yamagata University

Yusuke KUDO, Yuki NAKAJIMA, Toshiyuki SUGIMOTO, Yoshio HIGASHIYAMA

AC corona discharge occurring at a floated wire particle was investigated under the condition of high relative humidity ranging from 20 to 90%. When the particle was inserted vertically between parallel plate electrodes or placed at the surface of a silicone rubber sheet. Corona onset and breakdown voltage was measured for the various positions of the particle. In an air gap between the parallel plate electrodes with a spacing of 20 mm, relative humidity affected little corona onset voltage ad breakdown voltage. In contrast, corona onset voltage from the particle placed at the surface of silicone rubber sheet influenced by the humidity. The higher relative humidity, the higher corona onset voltage was obtained.

5pA-9

“Influence of High-Intensity Standing Sound Wave Field on Discharge”

College of Indust. Tech., Nihon Univ.

○Hiroki YAMAUCHI, Masahiko ITO, Tomoo NAKANE and Tetsuro OTSUKA

The behavior of intermittent sparkdischarges in high-intensity acoustical standing wave field was experimentally investigated.A point-point gap or positive-point-plane gap was locatedat the particle velocity antinode of an acoustical standing wave field, that was produced in a cylindrical acoustic tude. It can be obtained that the luminous part of intermittent spark discharges spread by the effect of high-intensity sound waves; spread to a section of rugby ball-like-shape with a point-point gap and spread to an open fan-like-shape with a positive point-plane gap.The relationship between spread width of luminous part of the discharges and the sound intensity was quantitatively measured and investigated.

5pA-10

“Formation of a powder particles cloud charged by pulse corona discharge”

Yamagata University

Toshiyuki SUGIMOTO

Formation of a charged particles cloud has been investigated experimentally using pulse corona charging method to obtain higher space charge density than that using dc corona charging. Powder particles were blown by an air flow and charged by pulse corona discharge or dc corona discharge. The electric fields formed by the clouds at the ground were measured to compare the charge mounts for pulse corona charging and dc corona charging method. The electric field reached at 210 kV/m in maximum for pulse corona charging. The pulse corona charging was found to be more effective than the dc corona charging because both a space charge effect and particle driving force in the corona charger were reduced.

5aB-1

“A proposal of a new evaluation method for plasma reactor performance”

Faculty of engineering, Soka university

○Nobuo HARADA, Tatsushi MATSUYAMA, Hideo YAMAMOTO

This study proposed a new parameter for performance evaluation of plasma reactor. This parameter was derived as the basis for mass based Specific Energy Density (mSED). VOCs were decomposed by SPCP reactor under various kinds of experimental conditions. Results showed that the decomposition ratio of VOC was expressed in terms of a discharge power (Pdis) or an input velocity (vs) which represented the amount of supplied pollutant in a unit time. In addition, the concentration of VOC decreased exponentially with increasing Pdis, and reaction constant kp was inversely proportional to vs. The α was obtained from the relationship kp and vs. Since the constant parameter α was valid regardless of the initial concentration and the flow rate, α was applicable to any reaction conditions. Compared with various type reactors by using α, it was demonstrated that SPCP reactor was as effective as packed-bed reactor.

5aB-2

“Charging of Particulate Products from the Decomposition of Xylene in Air under Electron Beam Irradiation”

Takasaki Radiation Chemistry Research Establishment, Japan Atomic Energy Research Institute

○Teruyuki HAKODA, Akihiko SHIMADA, and Takuji KOJIMA

Particles as oxidation-resistant products are produced from aromatic hydrocarbons in air by electron beam (EB) irradiation and can be removed from the gas phase with an electric field after their charging with EB-induced ions at high concentrations. In the present work, the charging rates of particles produced from o-xylene based on their number and volume concentrations and the polarities of charged particles were examined under EB irradiation with and without external electric fields applied to irradiated air mixtures. The charging rates based on number and volume concentrations increased from 31-37% to 48-55%　and 48-55% to 91-93%, respectively, with external electric fields from 0 to ±900 V/cm, independent of absorbed dose and initial xylene concentration.

5aB-3

“Analysis of Electron Beam Induced Particulate Products with Atmospheric Pressure Ionization Mass Spectrometer”

Takasaki Radiation Chemistry Research Establishment, Japan Atomic Energy Research Institute, **Faculty of Engineering, Gunma University

○Teruyuki HAKODA*, Toshihiro SAKO**, Akihiko SHIMADA*, Atsushi KIMURA**, and Takuji KOJIMA**

Dilute xylene in air is decomposed into gaseous and particulate products by electron beam irradiation. In the present study, the composition of the particulate products was analyzed at elevated temperatures up to 150 ℃ by an atmospheric pressure ionization mass spectrometer after vaporizing them into 1%v-H2/Ar gas mixtures. Chemicals at the mass numbers of 139-203 u with the peak interval of 16 u, which is the same mass number of oxygen atom, were observed as particulate products at the temperatures higher than 120 ℃. Particulate products at the mass number of 155-203 u could be produced by the combination of the particulate products having 139 u with oxygen atoms. The chemical having 392 u was also detected with peak heights lower than above particulate products, and such a substance having heavier mass is presumably one of the nuclei components of particulate products.

5aB-4

“Improvement of nano Particle Collection Efficiency”

Musashi Institute of Technology

Koichi Yuda

Diesel Exhaust Particle (DEP) is one of toxic substances in exhaust fumes emitted from diesel vehicles. If DEP obtain entrance into apparatus respiratorius, it is going to cause a cancer and embarrassment. Especially, there is high concentration DEP in a long-distance tunnel which is hard to ventilate. The nano particle accounts for majority of DEP. It is a particle for 50nm of diameter or less. Therefore it was not valued in emission restrictions based on mass. However the nano particle reaches to depth of respiratory organ because the particle size is small. It has misgivings about the danger to the human body of the nano particle is higher than large particle. In this study, Electrostatics Precipitator of the high removal of nano particle was developed. Collection efficiency of the nano particle by the difference between the electrode composition of the precharger and the applied voltage polarity was measured and examined.

5aB-5

“Development of Clean Booth for Pollen Allergen Prevention: Simultaneous Use of Electrostatic Precipitator”

College of Indust. Tech., Nihon Univ.

○Taichi ＭURAKMI，Yuto ＮAKAMURA，Mai ＨASHIMOTO，Tetsuro OTSUKA and Tomoo NAKANE

A compact clean booth was prepared as special sleeping room for hay fever sufferers and the miniaturization of the clean booth was attempted down to the dimensions of 1.5×2.5×2 mm. Also an electrostatic precipitator (ESP) was simultaneously employed to deaden the ambient noise and enhance the cleanliness of the booth. As a result, the cleanliness class from 10 to 1000 (0.3-0.5 μm) was achieved and these values proved that the present clean booth could be used for the pollen allergen prevention.

5aB-6

“PM transportation by gradient force”

＊Department of Ecological Engineering, Toyohashi University of Technology, ＊＊Department of Electrical Engineering, University of Tokyo

Satoshi SATO*, Yoshiko YAMAMURA*, Mitsuyoshi KIMURA*， Kazunori TAKASHIMA*, Shinji KATSURA*,**, and Akira MIZUNO*

Diesel exhaust soot removal using electrostatic precipitator (ESP) has been studied. But the suppression of the particulate matter (PM) must be developed furthermore. In this study, electrostatic precipitator with discharge plasma was investigated to cope with the slip of the PM. In this paper the collecting electrode in an ESP was modified in order to decrease the reentrainment of PM and to oxidize collected PM. The collecting electrode was metal triangle poles placed on an insulating plate. A pair of sharp triangle poles were put on a glass plate normal to the gas flow. One triangle electrode was connected to AC high voltage power supply and the other was grounded. Because the gap distance between the triangle electrodes were shorter in lower part of the triangle electrodes, electric field was highest at the bottom of triangles resulting in a gradient of electric field. In this reactor, the collected and agglomerated particles were pulled into the high electric field region at the bottom of the triangle electrodes due to gradient force. This newly proposed ESP transported PM into high electric field region and oxidized the PM by spark discharge generated between the bottom of triangle electrodes.

5aB-7

“Removal of PM using corona discharge and surface discharge”

＊Department of Ecological Engineering, Toyohashi University of Technology, ＊＊Department of Electrical Engineering, University of Tokyo

Ippei KOYAMOTO*, Satoshi SATO*, Yoshiko YAMAMURA*, Mitsuyoshi KIMURA*， Kazunori TAKASHIMA*, Shinji KATSURA*,**, and Akira MIZUNO*

Particulate matter (PM) from diesel engine causes serious air pollution. ESPs can accumulate PM at low pressure drop. As the accumulation of PM causes breakdown, it is necessary to remove the PM for stable operation. We expected that PM can be removed by discharge plasma. In this study surface discharge and barrier discharge were examined to remove accumulated PM. It was found that oxidation removal of surface discharge was 7.5 times higher than that of barrier discharge. When 3.6mg of PM was oxidized by surface discharge, the removal rate was 47.9%. The removal efficiency was 0.57[mg/kJ]. This value is very close to the minimum requirement for practical use.

5aB-8

“The Effect of Different Configurations of Collecting Electrodes on the Flow Visualization inside a Wire-Plate Electrostatic Precipitator (ESP) in the Vicinity of the Collecting Electrodes”

Toyohashi University of Technology

Ahmed ALY, Bong-Jo SUNG and Akira MIZUNO

In ESPs, collection efficiency for fine particles is significantly affected by the electric field and gas flow conditions. The purpose of this research is to visualize gas flow trajectory in the vicinity of the collecting electrode according to two different configurations of collecting electrodes. Results showed an obvious difference between the gas flow trajectory in the two ESPs, and this affects the collection efficiency of the ESP. Also it shows that the gas flow trajectory can be controlled by changing the surface properties of the collecting electrodes in the ESP.

5aB-9

“Back Corona Quenching in ESP by Saw-tooth Voltage”

Fukui University of Technology

○Ayumu IIJIMA and Tetusi NAKAGAWA

If the electric resistivity of an electrostatic precipitator of particle is high, it will be occurred a back corona discharge and will fall collection efficiency remarkably. The measure against a back corona used now is large-sized equipment, and is expensive. If a back corona can be controlled by making the direct-current high-voltage power supply currently used into saw-tooth voltage by easy reconstruction, an improvement of collection efficiency will be expected. As a result of measuring the amount of electrifications of the steel ball when applied the single phase full wave rectification voltage and saw-tooth voltage using the sttel ball falling method in the collecting space which has occur the back corona, the amount of electrifications of the direction which applied saw-tooth voltage increased. Moreover, the luminescence situation by a back corona also decreased and the control effect of the back corona has been checked. By applied saw-tooth voltage, it has checked that a back corona could be controlled slightly.

5pS-1

“Characteristics of Air Flow in the Vicinity of Building Models -Measurements of Fluctuating Wind Velocity by 3D-LDA-”

Dept. of Architectural Engineering, College of Indust. Tech., Nihon Univ.

Eizo Maruta

Hot Wire Anemometer (HWA) has been used as the method of measuring the gusty wind in wind tunnel tests. But, for HWA, the interaction between models and sensor supports was becoming a subject of discussion. So Laser Doppler Anemometer (LDA) has been need as a non-attached type. LDA in a gusty wind measurement has been pointed out that the output data rate was too low. Nevertheless, the considerations for improvement have not been sufficiently done. The objective in this research is to establish the measuring method of gusty wind by using 3D-LDA in wind tunnel tests and to make clear the 3-demensional complex flow in the vicinity of fuildings.

5pB-1

“Dependence on concentration of oxygen in oxidation of CO　−Comparison between a barrier discharge reactor and a excimer lamp−”

*Midori Anzen Co., Ltd.　　**University of Tokyo

〇Tomoyuki SAITOH*　Naoki SUGITA* Tetsuji ODA**

Carbon monoxide (CO) is toxic gas　because of strong affinity to hemoglobin. On the other hand carbon dioxide (CO2) that causes green house effect is not so harmful as CO. So the oxidization of CO gas into CO2 is a useful technique in the environmental indoor air quality. We test the excimer lamp that irradiates ultraviolet ray on the wavelength of 172nm and the barrier discharge reactor for oxidation of CO gas. As the results by the use of the excimer lamp, CO is oxidized within the region of 2mm from the surface of the lamp. However, the barrier discharge reactor gives higher efficiency of oxidization when comparing it by specific input energy (SIE). Especially when the concentration of oxygen gas is very low with high humidity, both of these two devices give the highest efficiency of the CO oxidation.

5pB-2

“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. In this study, a feasibility and performance of the reactor for TCE (trichloroethylene) decomposition in solution was investigated. It was found that TCE can be decomposed by oxygen active species in fine bubbles and, simultaneously, removed by aeration both in batch and continuous mode. In the batch mode, it was suggested that liquid phase reaction is dominant for TCE decomposition compared to gas phase reaction. In the continuous mode, it was shown that at higher gas flow rate the effect of transport of TCE from liquid to gaseous phase by aeration is more dominant for TCE removal, however, decomposition of TCE in solution by discharge become more dominant at lower gas flow rate.

5pB-3

“Promotion of the Decomposition Efficiency of Trichloroethylene and Investigation of Reaction Mechanism”

Department of Electronic Engineering, University of Tokyo

Koichi ONO, Sangbo HAN and Tetsuji ODA

Investigation of the plasma reactor concernig with the discharge gap is performed. The size effect of the inner central discharge electrode is examined by comparing 4 different sizes, 6mm, 10mm, 12mm and 16mm, respectively. The shortest discharge gap (0.4mm) realized the lowest initial discharge voltage and the highest TCE (trichloroetylene) decomposition efficiency. The ozone generation is also larger for shorter gap. To improve the TCE decomposition efficiency, the manganese oxide is used as the catalyst at the down flow of the plasma reactor. That effect is evaluated concerning with the byproducts versus the discharge power. We found that the activated species of O on the catalyst have possibility to decompose TCE into trichloroacetaldehyde (TCAA) and dichloroacetylchloride (DCAC) into phosgene.

5pB-4

“The Oxygen Content-Dependent Behavior of Different Catalysts in Plasma-Driven Catalysis For the Decomposition of VOCs”

AIST

Hyun-Ha Kim, Atsushi Ogata, Shigeru Futamura

In this work, the effect of oxygen content-dependent behavior of different catalysts was investigated for the optimization of the cycled system consisting adsorption and the decomposition of adsorbed VOC using an oxygen plasma. For all the tested catalysts, decomposition efficiency increased with oxygen content even at a fixed specific input energy. The effect of initial concentration and the temperature of oxygen plasma were also investigated using benzene as a model compound. The required energy (i.e. SIEeq) increased with the initial concentration of benzene. However, the temperature of oxygen plasma did not affect the required energy for the decomposition of adsorbed benzene.

5pB-5

“Significant Mechanism of Toluene Decomposition in Zeolite-Hybrid Plasma Reactor”

ational Institute of Advanced Industrial Science and Technology

Atsushi OGATA, Hyun-Ha KIM, Seung-Min OH, Hisahiro EINAGA, and Shigeru FUTAMURA

The enhancement effect for toluene decomposition is greatly different by the position of the zeolite in the zeolite-hybrid plasma reactor. In particular, active oxygen species such as ozone play an important role in the decomposition of toluene adsorbed into the micro-pore of the zeolite. We focused the reaction mechanism related active oxygen species by tracing the behavior of ozone generated in the reactor. It was found that the generation of the ozone was suppressed in the zeolite-filled region, although the concentration of ozone generated in the plasma region gradually increased in the flow direction of the gas. These results can be well explained that the removal efficiency of the toluene is enhanced by placing the zeolite in the downstream of the plasma region rather than placing that in the upstream.

5pB-6

“Decomposition Characteristics of Mixed VOCs in Nonthermal Plasma”

AIST

Masami Sugasawa, Annadurai Gurusamy and Shigeru Futamura

The decomposition characteristics of dichloromethane (CH2Cl2) - toluene by nonthermal plasma was investigated with a ferroelectric packed-bed reactor. The decomposition efficiencies of 109 ppm CH2Cl2 and 100 ppm toluene were not affected by mixing in the presence of O2. In N2, organic chlorides and cyanides were detected as byproducts from CH2Cl2 and toluene. However, no mixing effect was observed in byproduct formation. On the other hand, the number and quantities of the byproducts decreased as O2 content in the background gas increased. In the presence of O2, no oxygen-containing byproducts were newly detected.

5pB-7

“Decomposition of VOCs using Oxygen Anion Radicals Incorporated in Nanoporous Crystal 12CaO･7Al2O3 catalyst”

*National Institute of Advance Industrial Science and Technology (AIST),**Dept. of Mechanical Engieering, Tohoku Gakuin Univ.

Masateru NISHIOKA*, Youhei DAINO and Nariaki AGATSUMA*,**

A nonoporous crystal 12CaO･7Al2O3 can incorporate large amount of active oxygen ions (O-, O2-, O2- ) in the crystal. Decomposition of gas-phase VOCs by promoting the active oxygen ions in the 12CaO･7Al2O3 crystal was demonstrated. Acetaldehyde and toluene was studied for demonstrated VOCs. The oxidation temperature of acetaldehyde can be decrease 700 C to 300 C by existing the 12CaO･7Al2O3 catalyst. A conversion of acetaldehyde was promoted by extracting the active oxygen radical from 12CaO･7Al2O3 by applying an electric field. This result suggested that this method can be applied for the low temperature VOCs removable.

5pB-8

“Effect of Superimposing Barrier Discharge and Photocatalyst on VOC Treatment”

Musashi Institute of Technology

○Takashi Imuta, Yoshiyasu Ehara, Haruo Kishida, Tairo Ito

The theme of this paper is VOC (volatile organic compounds) treatment using electric discharge and photocatalyst (TiO2). When ultraviolet ray is irradiated to TiO2, O2− and OH− are generated. Because these have high reactiveness, organic compounds are oxidized and resolved. In this study, it was expected that discharge luminescence activated TiO2, therefore TiO2 was set up in discharge space. It was experimented that TCE (trichloroethylene) was treated by disharge in the cases of TiO2 presence or not presence. Additionally, flow rate and initial concentration of TCE were changed. As a result of this experiment, it is cleared that TCE removal increases by combining discharge and TiO2 if initial concentration of TCE is less than 50ppm.

5pB-9

“Adsorption and decomposition of gas phase VOC using fabricated carbonfiber and barrier discharge plasma”

Department of Biological and Chemical Engineering, Gunma University

Tomomi Kondo, Nobuyoshi Kitajima, Shin-ichi Mii, Takayuki Ohshima, and Masayuki Sato

Adsorption and nonthermal plasma removal of gaseous acetaldehyde was studied in novel plasma discharge reactor, in which fibrous activated carbon was used as both electrode and absorbent. After a fibrous activated carbon sheet put onto a glass plate was saturated with 200 ppm of acetaldehyde gas, 10 kV of AC high voltage was applied to fibrous activated carbon. The surface discharge was observed around the edge of the sheet of fibrous activated carbon. Acetaldehyde adsorbed in fibrous activated carbon was removed during plasma treatment, and complete decomposition of acetaldehyde was achieved within 60 min. These results suggested that continuous treatment with spontaneous adsorption and nonthermal plasma removal of VOCs is possible by using fibrous activated carbon as the high-voltage electrode.

5pB-10

“Toluene Concentration Using Honeycomb Adsorbent and Nonthermal Plasma Desorption”

Department of Mechanical Engineering, Osaka Prefecture University

○Tomoyuki KUROKI, Takeshi FUJIOKA, Masaaki OKUBO and Toshiaki YAMAMOTO

In general, the gas concentration of volatile organic compounds (VOCs) from painting and printing industries is low (in ppm levels) and gas volume is large. Therefore, it is expensive and inefficient to treat them directly. The gas concentration technique using adsorbent material combined with plasma is extremely effective. The conventional* *desorption processes use thermal desorption or pressure swing adsorption methods, which entails the additional costs of preparing high-temperature gas, stream, low-pressure state, apparatus, and energy.* *In the present study, we focused on toluene, which is a typical VOC compound. The toluene concentration technique using the plasma desorption was investigated in order to convert form a low concentration with high flow rate to high concentration with low flow rate, which results in small abatement system. The effects of background gas, flow direction and flow rate on plasma desorption were evaluated.

5aC-1

“THERMAL EMISSIVITY MEASUREMENT OF CARBON FIBER FLOCKED SURFACE”

Chiba Institute of Technology

○Shoichi Hasegawa、Tsutomu Isaka、Yasuo Sekii、Tomonao Hayashi

Following the previous investigation of measurement of reflectance of carbon fiber flocked surface, authors tried to estimated the thermal emissivity of carbon fiber flocked surfaces by calorimetric method. The sample used for thermal emissivity measurement was fabricated by pasting two pieces of flocked samples together, in which are embedded a heater and a thermocouple. The emissivity was estimated by measuring sample temperatures at thermal equilibrium in vacuum under thermal power loading. Establishing the thermal equilibrium in vacuum, a space chamber of 1050 mm diameter and 1206 mm depth was used. We obtained the value 0.96 as thermal emissivity of carbon fiber flocked surface, which was recognized to be greater than the emissivity of the surface of black paint coating.

5aC-2

“Development of automatic flocking machine with plotting technology”

＊ Tokyo Metropolitan JOTO Industrial Technology Institute , ＊＊ Tokyo Metropolitan Industrial Technology Research Institute

Yasuo TONOYA＊, Katsumi YAMAMOTO＊＊, Hiroshi SHIGEMATSU＊＊, Hideki KURIHARA＊＊, Isamu YAMAGUCHI＊＊ and Takashi MIYOKAWA＊＊

On the current flocking products we can flock only the whole surface of material. The developed automatic flocking machine can make the designed products as follows, (1) make the image data using computer aided design and so on. (2) apply the adhesive using plotting technology based on the image data. (3) flock the designed material using electrostatic power. The automatic flocking machine is composed of the device for applying adhesive and the device for flocking. The device for applying adhesive consists of three shaft control tables and dispenser. The device for flocking consists of two shaft arm table and flocking gun. The developed machine is suitable for high-variety engineer-to-order manufacturing because of flexibility design and maskinglessness.

5aC-3

“Optimization of Operating Conditions of Electrostatic Powder Coating using Atomized Powder Coating System with Atomized Particle Powder”

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

Mitsuru MATSUI*, Takashi TAKAHASHI** and Tsutomu ITO***

Fundamental parameters which determine the quality of coating in electrostatic powder coating, are discussed and three issues, mass flow rate (MFR) of powder delivering to gun, particle size distribution of powder, and amount of conveying air, have been derived as the most dominant parameters. The first issue has been resolved with the atomized powder coating system in which a newly designed MFR sensor and controller has been installed, as a result the system functions as a sensor based full automatic control system [Proc. IESJ, 28 (2004) 120-126]. The third issue, the amount of conveying air, which affects strongly to penetrating of powder inside recessed areas and electrostatic wrap effect is experimentally investigated using the atomized powder coating system with atomized particle powder. When amount of the conveying air is increased, coating thickness on the recessed area has increased evidently. Thus, increase of the conveying air from 80 l/min that is an empirical standard value at most industrial coating lines, to 120 l/min has yielded about 13% of increase in coating thickness.

5aC-4

“Improvement of the Charging Process for High-speed Electrophotography”

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. Instead of ordinary corona discharge, streamer discharge was tested for the present purpose using a metal drum with insulator layer on its surface. As a result, the charging speed obtained was very high, but sometimes charge distribution was not uniform and linear patterns of non-charging areas were observed. The distribution showed the tendency to become uniform by charging the drum surface repeatedly.

5aC-5

“Dependency of EHD effect with Spherical−Cylindrical Electrode System on Conductivity of Si Oil Medium”

Dep. Electrical engineering, Yamagata University

Koji Watanabe

A dielectric liquid in EHD (Electrohydrodynamic) pump is driven directly by an electrical force. Two well-known electrical forces, ion-drag force and electrostriction force, are involved with an EHD flow. In ion-drag phenomenon, contamination of the insulating liquid will be the major problem, while higher EHD pumping pressure can be obtained. We have investigated EHD phenomena with spherical electrode to aim a contamination free EHD pump system. It is reported that the EHD effect is drastically altered by slight conductivity.

5aC-6

“Electrostatic Process in Liquid-Liquid System (I)　-Production of W/O Emulsion by Electrostatic Atomization-”

Department of Electrical and Electronic Engineering，Oita University

Yusuke TAKAHASHI, Seiji KANAZAWA, Yukiharu NOMOTO

An experimental investigation of electrostatic atomization in liquid/liquid system was conducted with a view toward emulsification and demulsification processes. Fine water droplets were generated in silicon oil using a nozzle electrode with ac high voltage and a stable water-in-oil emulsion was produced without surfactants. The mode of atomization was observed as well as the trajectory of fine droplets flow. The diameter of fine droplets and their distributions were measured as a function of applied voltage and its frequency. Electrohydrodynamic induced liquid flow with water droplets played the important role for the formation of the emulsion.

5aC-7

“Development of NO generator for medical applications”

Kumamoto University*, Shinshu University

○Takao Namihira*, Douyan Wang*, Tsuyoshi Kiyan*, Sunao Katsuki*, Hidenori Akiyama*, Kazufumi Okamoto**, Shinichi Ohira* and Kei Toda*

Since NO was identified as effective in treatments involving endothelium-derived relaxing factor in 1987, inhalation of NO (iNO) has been widely used in the medical treatment of acute respiratory distress syndrome, acute lung injury, high blood pressure, and other related illnesses. Current iNO systems usually include a gas cylinder of N2 with a high concentration of NO. This system has an inherent risk of generating nitric dioxide (NO2) if leaked NO mixes with air. NO2 is thought to be toxic to the lungs. Therefore, a system that does not include storage of NO is very desirable for administering iNO.In this paper, Prototype of On-site NO generator, which includes a discharge reactor, a NO2-NO catalyst, a charcoal and a particle filter, is developed for animal experiments.

5aC-8

“Evaporation rate measurement of an oscillating droplet using electrodynamic balance”

Gunma University

Nao Saitou, Katsutoshi Fukai, Azuchi Harano

It is important to understand the mechanism of fine droplet evaporation under the unsteady flow for ingenious designs of the spray tower, the diesel engine and so on. However, the analyses for droplet evaporation have been only developed for the steady state flow. In this experiment, we adapted the electrodynamic balance (EDB) to establish the unsteady flow around the droplet by oscillating a single droplet by AC electric field. The enhancement of mass transfer from single oscillating droplet having been measured from DC voltage applied EDB device. The frequency and amplitude of the oscillation were controlled by means of ac and dc fields applied to the cylindrical electrodes of the EDB. It is found that the evaporation rate in the unsteady flow field is influenced by the frequency and amplitude of the droplet under 40μm oscillating and the enhancement is substantially larger than that predicted by quasi-steady-flow mass transfer.

5aC-9

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

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

○M. Hattori*, K. Takahashi*, T. Oizumi*, and K. Izumi**

To date, a multi-disk-type corona motor that consists of a number of multi-DVDs (Digital Video Disk) type of rotor and a number of dual-printed circuit boards stator was proposed and has been 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 taking it apart. To use the corona motor, an ozonic water generation system was constructed. This system has a small centrifugal pump, gaseous and liquid ozonic monitors, and a small dc motor for speed control of the corona motor. Most of the elements of this system are all computer controlled and measured using MATLAB/Simulink software and a DSP control board. The generating characteristics of gaseous ozone is the focus of our current report.

5aC-10

“Development of emulsification method by electric field and its application”

＊Department of Ecological Engineering, Toyohashi University of Technology, ＊＊Department of Electrical Engineering, University of Tokyo

○Michihiko NAKANO＊, Sayaka KUNITANI＊, Kazunori TAKASHIMA ＊, Shinji KATSURA＊, ＊＊ and Akira MIZUNO＊

Water-in-oil (W/O) emulsion has attracted attention to biological and combinatorial applications since water droplets in W/O emulsion are served as micro reactors. To produce emulsion, especially for their applications, stirring device or homogenizer is employed. However, methods by these devices are at risk for serious contamination since they are usually used in repeating fashion. Moreover, they need a certain amount of volume at least 1ml. In this paper, emulsification induced by electric field is presented. An electrode applying A.C. high voltage was placed inside a micro tube. 100ul to 500ul of W/O emulsion was formed when high voltage was applied. Diameter of droplets dispersed in the emulsion was measured in several experimental conditions. In addition, inhibitory effects of this method on polymerase chain reaction were investigated. When 5kVp of high voltage was applied for 30sec or 3kVp of high voltage was applied for 60sec, PCR amplification was not inhibited. Because the electrode inside micro tube was simply structured that made of glass capillary and tungsten wire, it must be very cheap and use disposable.

5pC-1

“Sterilization of inner wall of tubes using pulse discharge at low pressure”

*Department of Ecological Engineering, Toyohashi University of Technology, ** Department of Electrical Engineering The University of Tokyo

○Masakazu TANINO*, Isamu AMANO*, Kazunori TAKASHIMA*, Shinji KATSURA*,**, and Akira MIZUNO

A new type of low pressure sustained plasma is introduced for inner tube treatment. The newly developed plasma method has advantages of low temperature operation, time-saving and non-toxicity over the conventional methods, such as dry heat, steam autoclave, and ethylene oxide (EO) gas. Sterilization effect of discharge plasma on Bacillus subtilis on inner surface of tubes at low pressure was investigated using pulse discharge plasma. The system showed higher performance in terms of treatment time compared with conventional ones.

5pC-2

“Effect of PEF on Lysozyme refolding and structural change”

Department of Biologica and chemical Engineering,Gunma University

○Shinji WARABINO,Takayuki OHSHIMA, and Masayuki SATO

t has been suggested that PEF treatment can induce the refolding of denatured soluble enzymes. The effect of PEF treatment on soluble lysozyme, which has been investigated by many researchers molecular biologically and morphologically, was studied in this research. When 7kV/cm PEF was applied to partially heat-denaturated lysozyme solution, 16 % of enhanced lysozyme activity was observed. We also studied the difference of tryptophanyl fluorescence intensities before and after PEF treatment, and some conformational change seemed to be induced by PEF treatment. These results suggested that PEF treatment affects the conformation of lysozyme, that resulted in the change of lysozyme enzyme activity.

5pC-3

“High-efficiency Electroporation Using Field Constriction at Micro Orifife”

1Advance Co., 2 Dept. Mechanical Engineering, The University of Tokyo, 3 Dept. Physiology, Kyoto University, 4 Dept. MicroEnginering, Kyoto University

Osamu KUROSAWA1, Hidehiro OANA2, Yoshifumi WAKE2, Satoshi MATSUOKA3, Akinori NOMA3, Hidetoshi KOTERA4, Masao WASHIZU2

A novel method of electroporation, having no dependence on the cell size or shape, is developed based on a field constriction at a micro orifice. The device consists of an insulator plate, having an array of micro orifices with a typical diameter of 2 μm, and a pair of electrodes placed on both sides of the plate. Cells are immobilized at the orifices by aspiration, and a train of pulse voltage is applied to the electrodes. If the pulse duration is large compared with the time constant of the system, as it is the case with normal electroporation conditions, the field lines cannot penetrate through the insulator plate but converges into the orifice, so that field constriction is created at the orifice. This means that most voltage drop occurs in the vicinity of the orifice, and as a result, controllable voltage is imposed locally to the membrane there, so that reversible membrane breakdown occurs reproducibly irrespective of the cell size, shape or orientation. The required voltage is only a few volts, and pulse can be repeated without destroying the cell until adequate uptake of foreign molecules occurs. The experiments are performed using a spherical cell (human monocyte) and a non-spherical cell (murine myocyte), and uptake of a fluorescence intercalator dye YO-PRO-1 is demonstrated by a train of electrical pulses with an amplitude as low as 1.5 V.

5pC-4

“Continuous Separation of Cells using Dielectrophoretic Device with Porous Insulation Membrane”

*Faculty of Engineering, Gunma University, **Center for Advanced Science and Innovation, Osaka University

○Masaru HAKODA*, Motoko TOSHINAI* and Yoshikazu WAKIZAKA**

Dielectrophoresis (DEP) is a motion of dielectric particles caused by polarization effects in a non-uniform electric field. We apply the DEP to separate the viable and non-viable cells by considering the difference of permittivity between viable and non-viable cells. The development of the separator of the viable and the non-viable cell using DEP device which arranged a porous insulation membrane between the parallel plate electrodes was examined. Therefore, DEP velocities of cells were measured under the various conditions of the pore-diameter and the thickness of the membrane. Furthermore, DEP velocities of cells were analyzed by the simulation and it compared with the experimental value. Moreover, the separation of the viable and the non-viable cells was carried out using the continuous DEP separator. And the retention ratio of the viable cell was examined under the various conditions of flow rate, applied voltage, and electric field frequency. The retention ratio of the viable cell was greater than 90 % under the condition of 1 kHz, 70 Vpp, flow rate 0.3 ml/min. It is found that the porous insulation membrane type DEP separator was effective for the separation of the viable and the non-viable cell.

5pC-5

“Viable and Non-viable Cell Separation by Dielectrophoretic Filter”

*Center for Advanced Science and Innovation, Osaka Univ., **Faculty of Engineering, Gunma Univ., ***Masuda Research, Inc., ****Textile Research Institute of Gunma

Yoshikazu WAKIZAKA*, Masaru HAKODA**, Shin SUGIMURA**, Shinichi MII***, Nobuyoshi KITAJIMA****

Recently, studies of selective separation of cells using dielectrophoresis (DEP) have been performed. However, these are not applied to a large scale separation because they cannot do so efficiently. For the problem of the DEP separation, a DEP force is effectively acted only when it is close to electrodes. However, a DEP filter would be one of the answers for the large scale separation.

In this paper, viable and non-viable cell separation efficiency of the DEP filter was examined. First, dependency of applied AC electric field frequency on DEP velocity for the viable and the non-viable animal cells (3-2H3 cell) was discussed. The frequency response of the DEP velocity was different between the viable and the non-viable cells. And considering the result, the viable and the non-viable cells were separated using the DEP filter, and the best operating conditions such as the applied voltage, the applied electric field frequency and the flow rate were discussed.

5pC-6

“Selective detection of bacteria by using electropermeabilization-assisted dielectrophoretic impedance measurement with antigen-antibody reaction”

Graduate School of Information Science and Electrical Engineering, Kyushu University

Akio OHTSUBO, Kouichi SATA, Junya SUEHIRO and ○ Masanori HARA

This paper describes a selective detection technique of bacteria based on dielectrophoresis and electrical impedance measurements. The authors have previously proposed a fast and easy detection technique of biological particles called DEPIM (dielectrophoretic impedance measurement) method, and a selective detection technique by combining antigen-antibody reaction with the DEPIM. In this study, the authors demonstrated a selective DEPIM method by using immobilized antibody on a chip. It was difficult to detect Escherichia coli (E. coli) left on the chip on which E. coli-specific antibody was immobilized in advance by DEPIM, but it was possible using electropermeabilization-assisted DEPIM (EPA-DEPIM), which induced intracellular ion release through damaged cell membrane under high electric field pulses. It was also possible to selectively detect E. coli in a mix suspension with Serratia.

5pC-7

“Nano-printing of stretch-and-positioned DNA for Molecular Surgery”

epartment of Mechanical Engineering, The University of Tokyo

○Masafumi FUKE, Hidehiro OANA and Masao Washizu

Molecular surgery refers to the space-resolved operation on a molecule, where the target molecule is immobilized onto a solid surface and the operation is performed using position-controlled probes. In order to achieve a high resolution DNA surgery with enzyme-immobilized probes, the target DNA must be immobilized onto a solid surface with a stretched conformation, yet in such a way that the surface itself does not cause steric hindrance to the activity of the enzyme. In this paper, we propose and experimentally demonstrate a new method to realize such immobilization using nano-printing of DNA onto a microfabricated convex/concave structure. DNA is first stretched and anchored onto a micro electrode system using electrostatic stretch-and-positioning method. A substrate having a surface microstructure of periodical convex /concave texture is prepared separately, onto which the stretch-and-positioned DNA is made into contact to transfer DNA onto the texture. It is found that the binding strength between DNA and the surface must be carefully controlled for successful transfer, and is realized in this paper by a discharge plasma treatment of PDMS. DNA strands, being securely held at multiple locations along its length onto the convexes, while leaving other parts freely suspended above the concaves to allow interactions with enzymes, are obtained with the method.

5pC-8

“Stretching of yeast chromosomal DNA with globule-coil transition”

＊Toyohashi University of Technology, ＊＊University of Tokyo

○Jun Komatsu*, Kazunori Takashima*, Shinji Katsura*,**, Akira Mizuno*

Stretching and immobilization of genomic DNA molecules is important for high-throughput DNA sequencing which is based on controlled fragmentation of single stretched DNA molecule and analyzing of each fragment. In this study, yeast genomic DNA was recovered by electrophoresis and coil-globule transition to suppress random fragmentation of DNA during recovery and further process. Pulsed field gel electrophoresis demonstrated that the recovered globular chromosomal DNA has same size-distribution as one of native yeast chromosome. Because stretching and globule-coil transition should be carried under fluorescence microscopic field, dependence of fluorescence dye affinity to DNA molecules on both globular and coiled state of DNA molecules was investigated using a fluorometer. While intercalater dye YOYO-1 is likely to bind to coiled DNA, groove binder dye DAPI prefers globular DNA. The recovered DNA was also gently diluted with decondensation buffer for stretching. Observation of the stretched DNA showed some of DNA molecules were successfully stretched, but most of them were bundled or aggregated. This result indicates the recovered DNA are entangled each other during first phase transition, coiled to globular state.

5pC-9

“Uniform labeling of whole-DNA molecule with microparticles for single molecule manipulation”

Department of Ecological Engineering, Toyohashi University of Technology

○Junpei SAITOH , Jun KOMATSU, Kazunori TAKASHIMA, Shinji KATSURA, and Akira MIZUNO

A general genome analysis method called shotgun method needs to break down DNA into short fragments. Therefore, it takes a lot of time to recover original ordering information of the DNA. To solve this problem, we propose a new method to manipulate intended parts of DNA. This method is based on uniform particle labeling of DNA by using Psoralen-conjugated biotin. The particle labeled DNA can be easily manipulated by laser tweezers. At first, we confirmed that Psoralen-conjugated biotin inhibits neither restriction enzyme reaction nor PCR. We also demonstrated that avidin coated beads were linked to stretched DNA molecules on a glass substrate. This method will be applied for single fragment recovery from genomic DNA.

6aA-1

“Characteristics of Photoemission and Electrification of Glass”

Faculty of Science and Technology Tokyo University of Science

Syunsuke Naruse

Measurements of contact and frictional charging characteristics of various glass samples were carried out. In addition that characteristics of photoemission of these samples were measured. It was found that all glass samples had clear differences in charging characteristics. Threshold energies of photoemission measured were from 3.41eV to 3.87eV. As a result, there was a clear correlation between characteristics of photoemission and electrification.

6aA-2

“Charging characteristics of PVDF/PMMA polymer blends”

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

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

We investigated the charging characteristics of PVDF/PMMA polymer blends and their thermal annealing effects.

6aA-3

“Charging of Adhesive Tapes on Peeling off Adherends”

Graduate School of Engineering, Nagoya Institute of Technology

○Makoto HONAGA,Isao ISHIBE,Yasuro HORI

Charging behaviors of adhesive tapes were investigated on peeling them off various adherends. In order to measure amounts of charges accurately, a newly designed pre-amplifier in which an AD8627 operational amplifier is used was connected between a Faraday cage and an electrometer. The necessary static elimination of adhesive tapes was made by using an air ionizer, before the adhesive tapes adhere to an adherend, and before it is peeled off an adherend. A Nichiban vinyl tape VT-19 having rubber-type adhesives was used as adhesive tapes, and various polymers, three metals (Au, Cu, Al) and a silicon wafer were used as adherends. The charge of adhesive tapes on peeling off the PTFE or silicone rubber was maximum at the (+) charging end, and those off the PC or Nylon was maximum at the (-) side. The amount of charge on peeling off the PVA, PE or PP was very small. The series of charge amount on peeling off adherends is similar to the series of friction charging.

6aA-4

“Effect of strain on Tribo-electrification using ice”

Department of Geophysics, Graduate School of Science, Hokkaido University of Education

Hisashi SHIO

The triboelectrification of two pieces of similar quality ice specimens was investigated with asymmetrically rubbing. In this case, there is an asymmetry of heating in the experiments with crossed rods, the one has the rubbed surface developing a hot spot, the other has the rubber recerving a relatively small rise in temperature. The rubbed surface as like the hot spot was negatively charged against the other rubber as ribbon. Moreover, if the rubbing continued for a long time, the polarity of charge became reversed due to a changed nature at the rubbed surface of one of the specimens caused by the rubbing. The hot spot suffers more strain than the surface of the other rubber and only the hot spot with strain was recrystallized from a single crystal to polycystalline. In order to make a clear the effect of the strain on the triboelectrification of two kinds of specimens with isomeric properties, the one a strained ice specimen, the other a normal specimen, the experiment was carried out. As a result, the conclusion, namely, the more strained the specimen, the more the specimen got charged positively, was obtaine.

6aA-5

“LBM Study on Rayleigh Instability with Charged Droplet”

Faculty of Engineering, Soka University

○Takuya ABE, Tatsushi MATSUYAMA and Hideo YAMAMOTO

Rayleigh instability of charged droplet is well known phenomenon. Although the instability condition was revealed by Lord Rayleigh, how the deformation is developed after unstable state is still remaining as a question because of its dynamic nature. Therefore, a numerical simulative method will help to study the phenomenon. In this paper we report LBM (Lattice Boltzmann Method) simulation of the Rayleigh instability of charged droplet. We show an interesting extension of the LBM to involve electrostatic repulsive force working on the surface of an individual liquid droplet by means of momentum modification. The method successfully simulates the Rayleigh instability, in which a droplet is stretched its ellipsoidal shape when the electrostatic potential exceeds Rayleigh's threshold, on the contrary, a droplet with a less potential than the threshold deforms back to a spherical shape as a static form.

6aA-6

“lectrification Properties of Fibers and Fabrics”

Faculty of Textile Science and Technology, Shinshu University

Kazutoyo KUROKI, Saori ANDO, Isao NAKAMURA and　〇Keiji OHARA

Electrification charges due to frictional and corona electrification of nylon strings, nylon gauze and nylon fibers extracted from the gauze were measured and analyzed. The results showed the possibility of estimating the electrification properties of fabrics on the basis of the charging properties measured for fibers.

6aA-7

“Measurement of Force Curve due to Electrostatic Charge on a Particle with AFM”

Faculty of Engineering Soka University

Masaaki Otsuka Tatsushi MATSUYAMA and Hideo YAMAMOTO

In this reserch, a force curve working on a particle was measured with atomic force microscopy(AFM). Obtained force curve was evaluated by disk-to-disk charge interaction model. As a result, the fitted curve was corresponding to the data. As for this, it was confirmed that the data was due to electrostatic force. In the measurement using 8 kinds of metal as a contacting target, the data showing relation between the obtained charge density and the work function of meatal target was scattered. However, the strong relation between contact area and charge density was found. The cause of these results has been unknown. These points will be necessary to study in more detail in the future.

6pA-1

“Automatic Arrangement of Fictitous Charges and Contour Points in Charge Simulation Method by Immune Algorithm”

Electrical and Electronic Engineering, Tottori University

○Ryo NISHIMURA, Katsumi NISHIMORI

We adopt an Immune Algorithm (IA) to an arrangement problem of the fictitious charges the contour points in charge simulation method. First, the arrangement of the charges and the contour points is given randomly. Then, it is automatically adjusted by using IA in order to improve the accuracy of the electrode surface potential. We show that the electrode potentials can be accurately imitated for 3-D asymmetrical electrode system of which search domain is too large to determine the charge and contour point arrangement appropriately by Genetic Algorithm (GA).

6pA-2

“Electrical Properties for TiO2 Thin Films Having Photocatalytic Activities.”

College of Industrial Technology , Nihon University

○Takahiro Hayakawa, Kiyozumi Niizuma, Yoshio Utsushikawa

In this paper, the authors clarified electrical properties for TiO2 thin films having photocatalytic activities prepared under Ar+O2 atmosphere by RF magnetron sputtering method. From the result of XRD, crystal structure of anatase type was formed in TiO2 thin films prepared under Ar+40%O2 atmosphere. For TiO2 thin films prepared at gas pressure 3.0 Pa under Ar+40%O2 atmosphere, limited contact angle for water showed 9 under UV irradiation for 240 min. and absorbance for coloring matter of methylene blue showed -0.067 under UV irradiation for 120 min. Therefore, photocatalysis activities were the most excellent at gas pressure 3.0 Pa under Ar+40%O2 atmosphere. Moreover, it revealed that electrical resistivity ρ for TiO2 thin films prepared under the same conditions changed from 8.0×103 Ω･m to 2.0×10-2 Ω･m under UV irradiation for 60 min. It clarified that electrical properties and photocatalytic activities are considerably influenced gas pressure in preparing TiO2 thin films.

6pA-3

“Manufacturing Electric Wire Using Biodegradable Polymer”

＊Graduate School of Engineering, Kansai University、＊＊Imoto Mechanical Engineering

＊Yuuki Kawachi、＊Masahiro Honda, ＊＊Kenji Imoto, ＊Takayuki Yamakita, ＊Yoshiro Tajitsu

We developed an interesting instrument for manufacturing a biodegradable-polymer-insulated cable, with a variety of new functions. Using this instrument, we manufactured a poly-l-lactic acid (PLLA)-insulated cable. We measured the basic electrical insulation characteristic of the PLLA-insulated cable, and the following results were obtained. The mean breakdown strength of PLLA-insulated electric wire was approximately 3.5 times that of a polyvinyl chloride-insulated electric wire (VVF cable). Also, the bending and weather-fastness tests of the PLLA-insulated electric cable was performed. We obtained good results.

6pA-4

“Charge distribution of Potassium Salt Ionomers of Ethylene Copolymer”

DuPont Mitsui Polychemicals Co., LTD., Graduate School of Engineering,

Kansai University

Nobuyuki Maki

Our objective is to analyze the mechanism of electric charge behavior of potassium salt ionomers of ethylene copolymer. First, we measured the space charge distributions of potassium salt ionomers of poly (ethylene methacrylic acid) using the pulsed electro acoustic method. When positive dc voltage was applied to an electrode of the potassium ionomer sample, negative charges are produced and distributed in the potassium ionomer sample. On the other hand, charge induced on the surface of the counter electrode was not observed. From the presence of the characteristic space charge distribution, we speculate that there exists a microscopically inhomogeneous structure that affects ion transport processes in the potassium ionomer sample.

6aB-1

“Improvement of the focused excitation laser shape to measure atomic oxygen with TALIF in atmospheric streamer discharge”

School of Engineering, University of Tokyo

Kei Takezawa, Ryo Ono, Hisashi doita, Tetsuji Oda

TALIF (Two-photon Absorption Laser-Induced Fluorescence) is used for the measurement of the atomic oxygen in the non-thermal plasma. But focusing the excitation laser on the spot has two problems. One is generation atomic oxygen from O2 by photodissociation which is not related to the discharge because of high power density of the tightly focused laser beam. And the other is that the exitation laser focused on the spot can't always catch the nonuniform plasma like stremer discharge.

TALIF measurement needs much laser energy density, but the high energy laser density also causes the direct atomic oxygen dissociated from the oxygen molecule which results in overestimation of the atomic oxygen radical generated by the discharge plasma. Focused laser beam measurement causes another problem that the atomic oxygen observation area is too small and the beam cannot pass through the central part of the streamer. At the same time, the author would like to know the vertical distribution of the atomic oxygen below the needle. For those conditions, the excitation laser beam is focused to a rectangle pattern by the cylindrical lens. The sensitivity and spatial resolution on the vertical direction was kept and a higher reproducibility of each shot response is obtained.

6aB-2

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

* 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*, Yukiharu NOMOTO*, Marek Kocik**，Jerzy Mizeraczyk**，Jen-Shih Chang***

The LIF detection of the hydroxyl (OH) radicals was performed in a nozzle-to-plane electrode system having an electrode gap of 30mm during the steady-state positive streamer corona discharge in open air. For monitoring the ground-state OH radicals, OH ( X2П(v’’=0)→ A2Σ+(v’ =1) ) transition at 282nm was used. Time relationship between the streamer discharge current, probe laser and LIF signal was measured. Two-dimensional OH distribution in the DC corona discharge was also investigated. The obtained results showed that the ground-state OH radicals were observed within the region of branching streamers.

6aB-3

“Two-Dimensional Distribution Measurement of Atomic Oxygen in Atmospheric Nonthermal Plasma”

School of Engineering, University of Tokyo

Hisashi doita, Kei Takezawa, Ryo Ono and Tetsuji Oda

Nonthermal plasma is a very effective method in removing environmental pollutants such as volatile organic compounds and NOx in the flue gas. However, chemical reactions in atmospheric pressure plasma have not been fully understtod yet. The purpose of this research is elucidation of plasma parameters. The authors observed behavior of atomic oxygen which is assumed to play an important role in removal process of poisonous gas in plasma. In this study, a pulsed dielectric barrier discharge method was used for generating nonthermal plasma. Atomic oxygen was observed with two-photon absorption laser induced fluorescence (TALIF) spectroscopy. The results show that there is a correlation between the density of atomic oxygen and electric field intensity which influences the streamer channel. It is also aparent that atomic oxygen decreases during approximately 10μs after the discharge.

6aB-4

“Ozone Production Process in Pulsed Dielectric Barrier Discharge”

The University of Tokyo

○Ryo Ono, Tetsuji Oda

Ozone production process in pulsed dielectric barrier discharge (DBD) is studied by measuring spatial distribution of ozone density using two-dimensional laser absorption method. DBD occurs in a 6 mm point-to-plane gap with a 1 mm thick glass plate placed on the plane electrode. Positive high-voltage pulses of 20 to 30 kV are applied between the DBD gap. First, propagation of DBD is observed with a short-gated ICCD camera. Primary streamers develop from the anode to the cathode when a high-voltage is applied between the gap, then secondary streamers propagate from the anode and surface discharge occurs on the glass plate. Next, ozone spatial distribution is measured. It is shown that ozone is mostly produced in secondary streamer and surface discharge channels, while only a small amount of ozone is produced in primary streamer channels. The rate coefficient of ozone production reaction, O + O2 + M -> O3 + M, is estimated to be 2.5 x 10(-34) cm6/s.

6aB-5

“Ozone generation by the corona discharge between needle electrode and the plate electrode”

Mitsubishi Electric Corporation

〇Takuya FURUHASHI, Akira SHIGA, Shiro TAKEUCHI and Yoji FUJITA

The ozone generation by the corona discharge between needle discharge electrode and a plate electrode was investigated. The amount of ozone generation was changed by the material and configuration of needle discharge electrode. That's study showed there were an optimal needle material and configuration of needle discharge electrode affect ozone generation. The amount of the ozone generation were decreased by the metal with the catalytic oxide.The ozone generation decreases by thinning the thickness of the needle electrode. The ozone generation were increased, as the needle base width of the needle electrode became longer. The ozone generation were increased when the width of the plate electrode was small. The ozone generation could be controlled by the catalytic oxide on the surface of needle electrode and the less volume of corona discharge.

6aB-6

“Effective Ozone Generation of a Wire-Plate Discharge System with a Slit Barrier”

Dept of Electrical Engg, Graduate School, Kyungpook National University

OJae-seung Jung, Deog-hyun Hwang, Tae-hoon Kim, Jae-Duk Moon

A wire-plate discharge system with a slit barrier has been proposed and investigated experimentally by focusing on the discharges on the slit barrier. This wire-plate discharge system with a slit barrier can generate a corona discharge twice, once from the corona wire electrode and a second time from the surface and the slits of the slit barrier. As a result, this proposed wire-plate discharge system with the slit barrier can produce greatly increased ozone than without the slit barrier. The discharge mechanism of the wire-plate discharge system with the slit barrier showed that there would be hard to arc-discharge and breaks the system down directly because of the blocking action of the slit barrier. This type of wire-plate discharge system with the slit barrier could be used for effective ozone generation as a means with regard to the removal of pollutant gases.

6aB-7

“Production of Atmospheric Pressure Non-Thermal Plasma Using Capacity-Coupled Electrode”

Iwate University*, Ibaraki University**, Tohoku University***

〇Koichi TAKAKI*, Reina Ohmukai*, Seiji MUKAIGAWA*, Tamiya FUJIWARA*, Hiroshi MASE**, Noriyoshi SATO***

Capacity-Coupled Multi-Discharge (CCMD), which was substantially a self-quenching discharge in the same manner as the dielectric barrier discharge (DBD), was newly developed as atmospheric plasma source. We employed a coaxial cable as a capacitor to quench the discharge within short duration and controlled an input energy into the discharge plasma. A needle-to-plane electrode configuration was used as discharge gap. The needle and the plane electrodes were connected to the quenching capacitor and to an ac high voltage power source, respectively. The discharge gap was put in atmospheric pressure air with setting to be 1 mm in gap length. The discharge was successfully quenched within 40 ns by 9.4 pF quenching capacitor. The energy into the plasma per one cycle of applied voltage was 0.24 mJ which was almost two orders higher than that of needle-to-plane DBD (2.5 mJ). The power into the plasma increased stepwise with applied voltage. This stepwise increase is in good agreement with a theoretical prediction.

6aB-8

“Feeding of electrically charged cutting-fluid mist for efficient and clean machining”

*EnomotoBeA co.Ltd, **Toyohashi University of Technology, *** Nagoya Institute of Technology

Masayuki Okamoto Yutaka Hatanaka*, Michihiko Nakano**, Humihiro Itoigawa*** , Akira Mizuno**

In machining process, production cost and waste material can be reduced by replacing the cutting fluid from a conventional “flood type emulsion” to an “oil mist” {or “minimum quantity lubrication (MQL) system”}. However, since the MQL system has tendency with the surface roughness become worth in relatively heavy machining parameter, and has a problem of oil fume generation to the atmosphere, the application of the MQL has been limited.

In the intermittent machining, oil film on the tool surface is repeatedly formed and stripped off. There is no oil film on tip of the tool after a cycle of cutting; therefore the surface of the tool becomes bared metal. Supplying the cutting oil mists that are electrically charged by Corona discharge to the tool, the mists can be stuck on the bare tool surface selectively and form oil film.

Through the series of tests by measuring cutting force, it was observed that the cutting force is reduced using the charged cutting oil mist, especially in MQL condition. In addition, up to 74% of oil fume was removed when the mist was electrically charged by D.C. High voltage when the tool and the wall was grounded.

6pS-1

“The Restoration of Classic Airplane at Industrial Archaeology”

College of Indust. Tech., Nihon Univ.

Masahiro Mino

6pB-1

“Decomposition of LAS Solution by Pulsed pPower Discharge in Gas Phase”

Faculty of Engineering, Yamagata University

○Yasushi MINAMITANI and Yoshio HIGASHIYAMA

A method for decomposing organic compound by spraying water solution into non-equilibrium plasma in gas phase was investigated using a pulsed-corona discharge reactor. The corona reactor used consists of a discharge wire and a cylindrical electrode. Water solution of sodium dedecylbenzensulfonate (C12-LAS) with a concentration of 10mg/L was sprayed into the reactor from a showerhead. The sprayed water solution was circulated into the reactor. C12-LAS was decomposed up to about 90 % by one time exposure in the discharge for the discharging power of 6 W.

6pB-2

“Pilot-Scale NOx Removal from Boiler Emission Using Indirect Plasma and Chemical Hybrid Process”

Department of Mechanical Engineering, Osaka Prefecture University

○Masaaki OKUBO, Tomoyuki KUROKI, Hidekatsu FUJISHIMA and Toshiaki YAMAMOTO

The pilot-scale NOx removal from boiler emission was performed using our proposed indirect plasma and a chemical hybrid process. The flue gas flow rate was in the range of 450 ~ 1,470 m3N/hr, the gas temperature of 280 C, and NOx concentration of 30 ppm for gas firing and 70 ppm for oil firing, respectively. The NO2 oxidized by the indirect plasma was further reduced by a Na2SO3 solution chemical scrubber to N2. The NOx removal efficiency for gas firing exceeded 90%. It was known that the quality of wastewater was proved to be disposable.

6pB-3

“Desulfurization reaction mechanism of a Na2CO3 droplet using electrodynamic balance”

Gunma University

Azuchi Harano, Akira Akahoshi

Desulfurization reactions of a levitated single Na2CO3 droplet under high humidity were followed by electrodynamic balances (EDB) coupled with a Raman spectroscopy. The changes in weight and chemical composition of the single droplet were measured by DC levitation voltage applied to EDB and Raman spectra, respectively. The reaction product between SO2 and aqueous solution droplet of Na2CO3 depended on exposure time of SO2 gas in EDB chamber. The Raman spectra show that the product was nearly all Na2SO3 for short exposure time, but for long exposure time, the addition of SO2 to Na2SO3 led to NaHSO3 (or NaS2O5) as final product. And the produced NaHSO3 (or NaS2O5) particle turned back to Na2SO3 through the emission of SO2 gas under high humidity in

the absence of SO2. Gravimetric analysis based on the DC levitation voltage also indicated that a series of above reactions occurs under desulfurization reaction using the desulfurizing reagents containing Na. It has been demonstrated that EDB was a powerful tool for the kinetic studies of fine droplet such as desulfurization.

6pB-4

“Improvement of de-SO2 Efficiency of Pulsed Corona Discharge by Water-Based Radicals Produced by a DC Corona Discharge”

Department of Electrical Appliances and Applied Electronics, Dalian University of Technology, Dalian 116024, P. R. China

Jie Li

Abstract： Positive DC corona discharge is formed with nozzle-plate electrode configurations, in which the water vapor is ejected through the nozzle points. The purpose is to ionize the water molecules, increase the water-based radicals, and thus improve the de-SO2 efficiency of pulsed corona reactor. In this paper, we have measured water ions by Four Stages Molecular Beam Mass Spectrometer and diagnosed the water-based radicals by Emission Spectrograph. A conclusion on the formation of ions and radicals with DC corona discharges can be drawn. When the nozzle-plate electrode system is assembled in the front of the pulsed corona plasma rector, the water-based radicals ejected from DC corona discharges electrodes can increase the de-SO2 efficiency of pulsed corona discharge plasma.

6pB-5

“Characteristics of liquid-liquid dispersion and radical polymerization of plastic monomer using pulsed dicharge plasma in water.”

Department of Biological and Chemical Engeering, Gunma University

○Ikuyo KUROIWA, Norihisa MORITA, Takayuki OHSHIMA, and Masayuki SATO

High voltage pulse may have many applications such as environmental remediation by produced active species in the plasma under gaseous or liquid medium. In water phase, the high voltage pulse creates high intensity electric field at the electrode tip and also creates plasma with generating OH radical. In the present study, liquid-liquid dispersion by pulsed electric discharge was tried to make uniformly sized water glass droplets, which were solidified due to dehydration, and then converted to silica beads due to de-Na having a diameter of several 10s mm or below. OH radicals that were generated in the pulsed discharge plasma in water initiated polymerization of plastic monomer (e.g. methylmethacrylate (MMA), styrene, acrylic resin, etc.). MMA monomer was dispersed into fine droplets by high voltage pulse and they were polymerized to PMMA (polymethylmethacrylate) particles having a diameter of 1 2 mm.

6pB-6

“Effects of Reaction Temperature and Voltage Properties on CO2 Reforming of Aliphatic Hydrocarbons with Nonthermal Plasma”

AIST

Shigeru Futamura and Annadurai Gurusamy

CO2 reforming of methane, propane, and neopentane was investigated with a ferroelectric packed-bed and silent discharge plasma reactors in N2 at temperature from 303 to 433K. The conversions of the substrate hydrocarbons and CO2, and the yields of H2 and CO were expressed as functions of reactor energy density irrespective of voltage waveform. The positive temperature effect on the hydrocarbon conversions and the product yields can be ascribed to the promotion of secondary decomposition of the hydrocarbons induced by radicals formed in situ because reactor power consumption was not affected by reaction temperature at the same frequencies and peak-to-peak voltages. At 303K, the reactivity of the hydrocarbon decreased in the order: neopentane > propane > methane. At 433K, propane and the neopentane showed the same reactivities. The molar ratio of H2 to CO was affected by hydrocarbon structure, but not by reaction temperature. Carbon balances for all the hydrocarbons were better at 433K than 303K, suggesting the higher reaction efficiencies at 433K.

6aD-1

“Effect of Residual Space Charge on Eliminating Current of Soft X-ray Air Ionizer”

The Polytechnic University

○Ryuta YOSHINO, Kazuo OKANO

A soft X-ray air ionizer is widely used for static control in manufacturing process of electronic device such as LCD because of the ｃcontamination free. Unwanted residual space charge distributes above the charged substrate to recombine with wanted charge and reduce the static elimination speed in the eliminating process. The grounded grid located between the soft X ray source and the charged substrate was proposed to absorb the residual charge and increase the elimination speed.

It was found that the grid play an important role to increase the static elimination speed.

6aD-2

“Characteristics of Electrostatic Charge Elimination by Dry Fog Ionizer”

Faculty of Science and Technology Tokyo University of Science

Atsushi Tanaka

The characteristics of the dry fog ionizer which can convey high-density ions to a position apart from it was investigated. Using a fan set behind the nozzle, the maximum value of the ion density in the space was 1840nC/m3 at the position 1m apart from the ionizer, which was 10 times as much as that without the fan. The optional position of the corona electrode system against the nozzle was experimentally decided.

6aD-3

“Space Charge Concentration Control of Air Ionizer with Ceramics transformer”

The Polytechnic University

○Shouta UJIIE, Kazuo OKANO

An airionizer with ceramics transformer is one of promising candidates in an inspection process of an LSI manufacturing factory because of low noise and small size. A control grid was proposed to adjust the final voltage of the charged body. The relationship between applied voltage to the control grid and the final voltage were measured. It was found that the final voltage of the charged body was controlled by the voltage applied to the control grid.

6aD-4

“Ion Balance Control of AC Corona Ionizer”

Faculty of Science and Technology Tokyo University of Science

Haruki Sasai

Various ionizers are widely used in the clean room for manufacturing electronic devices in order to prevent electrostatic hazard. However these ionizers could not eliminate a charged object perfectly because of unbalance of positive and negative ions generated by corona discharge. In this paper, we will report the results of investigation for ion balance control of AC corona discharge by means of applying voltage to the ring electrode in front of needle electrodes. The error ranges of the bias voltage and the AC corona voltage which are necessary to restrict the potential of the charged body after elimination under 1 and 10 V were obtained experimentally.

6aD-5

“Modeling of charge neutralization with ac corona ionizers--part I: the effect of the relationship between discharge frequency and airflow on the fluctuation of offset voltage”

National Institute of Industrial Safety

A. Ohsawa

This paper discusses the charge neutralization with ac corona ionizers investigated by a computer model, in particular, part I investigates the effect of the relationship between discharge frequency and airflow rate. The one-dimensional fluid model consists of a model for ion sources, the continuity equations for ions, Poisson's equation for the electric field, and the circuit equation for solving the potential of the object to be neutralized. The model shows that the neutralization strongly depends on the relationship and demonstrates that at relatively high airflow velocities, the charges of objects cannot be neutralized. It is determined that the essentials for sufficient neutralization are that in the region of ion transport, the density distributions of positive and negative ions have no fluctuation and the space charges by them are quasi-neutralized at a steady state. To get such distributions, we suggest that attention should be paid to the relationship in ac ionizers.

6aD-6

“Modeling of charge neutralization with ac corona ionizers--part II: the effect of discharge frequency on charge decay time”

National Institute of Industrial Safety

A. Ohsawa

Part II of this paper focuses on the effect of discharge frequency on charge neutralization time. Experiments with ac corona ionizers have often observed that the neutralization time decreases with increasing frequency while it almost saturates at higher frequencies. This paper gives the theoretical interpretation for this phenomenon, in which the model agrees with the experimental results. The frequency dependence is caused by the electric field created by the potential of the object to be neutralized and created by space charges of ions. In particular, the quasi-neutralization in the region of ion transport described in part I is an important factor to create the most effective field distribution for neutralization, resulting in higher density distributions of ions and higher drift velocities lead to faster decay. The saturation of the neutralization time with frequency can be explained by that when the distributions of ions are effectively quasi-neutralized with increasing frequency, the distributions become almost the same because of ion generation independent of frequency. In summary of parts I and II, the quasi-neutralization and no fluctuations in positive and negative ion distributions in the transport region are crucial for neutralization with ac corona ionizers.

6pD-1

“Waveforms of Discharge Current from Charged Human Body(IV)”

Department of Electrical Engineering, Tokyo University of Science

○Takenori SAWAI, Takahiro YOSHIDA and Noriaki MASUI

In this paper, the relationship between waveforms of discharge current from the charged human body and the body potential is discussed for three subjects. Discharge is occurred between fingertip and earthed metal sphere approaching at 0.4mm/sec. The body potential is from ±2kV to ±10kV. Waveforms for ±2kV are similar and have a high amplitude impulse at the wavefront. In case of the positive discharge, appearance ratio of waveforms of discharge current with high amplitude impulse at the wavefront is over 50% under +5kV whereas negative discharge shows the same ratio under -3kV. The relationship between waveform of discharge current and discharge pattern appiared on the fingertip is also discussed.

6pD-2

“Time Dependence of Frequency Distribution of Discharge Current from Charged Human Body”

Department of Electrical Engineering, Tokyo University of Science

Takahiro YOSHIDA, ○Keigo KUBOTA, Takenori SAWAI and Noriaki MASUI

In this study, we analyze the correlation between time and frequency of the waveforms of discharge currents from the charged human body by using the spectrogram. Body potential is from ±2kV to ±10kV. When the body potential is lower than +4kV, most the waveforms have fast rise and large peak current at the wavefront. The high frequency component appears on the wavefront of the discharge current. Especially, in case of the waveforms for +4kV, most wavefront contains frequency component over 500MHz. When the body potential is higher than +6kV and negative, frequency component is even in the maximum around 200MHz. Frequency component from DC to 20MHz with larger power appears behind the wavefront.

6pD-3

“Electrostatic discharge characteristics through conductive rubber”

National Institute of Advanced Industrial Science and Technology, Faculty of Engineering, Kyusyu Sangyo University**

○Eishi KURODA*, Toshiyuki NAGAISHI**,Yoshio NAKAYAMA*, Masatake YOSHIDA* and Syuzo FUJIWARA*

The electric resistances of conductive rubber and conductive plastic were measured and then what influence the conductive materials gave to the electrical discharge characteristics when the electrical discharge was generated on those surfaces was examined. Conductive rubber acts on a dangerous side because of making the electrical discharge circuit easy to form as known well. When the electrical discharge was caused through conductive rubber placed between electrodes, the majority of the energy consumed between electrodes showed consumption by the gaseous discharge on the surface of conductive rubber in this report. It has been understood that the electrical discharge caused on conductive rubber is equally dangerous to the electrical discharge between metallic surfaces without conductive rubber.

6pD-4

“Experimental Study on Ignitability of Dust Clouds due to Electrostatic Spark in Electric Field with Corona Discharge”

*Independent Administrative Institution, National Institute of Industrial Sagety, **Seoul National University of Technology, Department of Sagety Engineering

○K-S CHOI*, M. YAMAGUMA*, K-T MOOM** and J-H HOUNG**

This paper is a report of the ignitability of dust clouds due to an electrostatic spark in an electric field with a corona discharge. The ultrasonic vibration-type apparatus for measuring the ignitability of an electrostatic spark of dust clouds and polyester powder were used in this study. The ignitability of dust clouds was confirmed to have decreased in the electric field created by the corona discharge. The reduction was dependent on the voltage applied to the wire electrode of the corona discharger. The experimental details including the discussion are described in this paper.

6pD-5

“Development of an apparatus for predicting static charge in a glass-lined chemical vessel

and proposal of a method for screening chargeable slurries”

○Mizuki YAMAGUMA*, Tsutomu KODAMA*, Yoshiyuki ENDO**, and Shonosuke KAMACHI***

*National Institute of Industrial Safety, **Sumitomo Chemical Co. Ltd., ***Technology Institution of Industrial Safety

In chemical industry, there have been a lot of reports about mechanical damages like pinholes due to the electrostatic discharge on the wall of glass-lined (GL) chemical vessels, where slurries containing low-conductive liquid and low-soluble powder are rigorously stirred up. To cope with this problem, we have developed an easy-to-operate, desktop electric field measuring system for predicting the charge generation in a GL vessel containing a slurry concerned. Lots of combination of solvent and powder were put to the test. The electric field strengths depended on the vertical location of the sensors, the conductivity of solvent, the solubility of power, the revolution of stirrer, etc. A typical distribution and trends of electric fields during stirring up were discovered. A practical screening method to pick out potentially hazardous slurries in advance using our apparatus is proposed.

6pD-6

“A Novel Technique of Charge Elimination of the Suface Charge on the Electrostatically Charged Liquid and the Prevention of Electrostatic Spark Ignition”

*REC RD INC, **Tokyo Denki University

○Yasushichi GOSHO* and Teruo KANEDA**

We propose a novel technique of charge elimination of the surface charge on the electrostatically charged liquids. This can be achieved to float a flexible conducting float on all over the liquid surface. When this technique is used for an oil tanker, the fuel handling operation can be made quickly because the liquid fuel charging caused by the flowing electrification is always eliminated by the presence of the flexible conducting float on the liquid surface.. In the case of an oil storage tank, similarly, a quick handling operation is possible and it will bi expected to reduce the handling expenses. The proposed technique is so constructed as to withstand a vilolent earthquake and liquid sloshing is expected to be suppressed by the presence of the flexible float.