2014 Annual Meeting of The Institute of Electrostatics Japan
Hiroshima International University
September 7-8, 20148aC-1
September 8th (Mon.), <10:30-11:45>
Room 3Development of Advanced Water Treatment System Using
Discharge-induced Plasmas○Seiji KANAZAWA*, Yuki ANAN*, Hiroyuki HAYASHI*, Shuichi AKAMINE*,Ryuta ICHIKI*,Taketoshi YAMAMURA**, Yutaka YAMAHIRA**, and Youichi
HONZI** Faculty of Engineering, Oita University** TRC Co., Ltd.

Abstract:
Advanced oxidation processes (AOPs) are well known for the treatmentof waste water. AOPs are facilitated by the use of the combination of UV, ozone,and chemical agents such as hydrogen peroxide. Especially, it is consideredthat the hydroxyl radicals (・OH) play the important role in the process. In thisstudy, a novel advanced oxidation process using the discharge-induced plasma
is proposed. We have developed a system which is combined with filtration,ozonation, and plasmas. The basic property of the discharge-induced plasma
is introduced and then the performance of the system is evaluated.

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

8aC-2
September 8th (Mon.), <10:30-11:45>
Room 3

Plasma characteristics of discharge in a cell culture medium○Yusuke Sato*，Takehiko Sato**，Daisuke Yoshino***Graduate School of Engineering, Tohoku University，**Institute of Fluid ScienceAbstract:
To apply a plasma directly to cells, generation of plasma in a cell culture
medium and its characteristics have been investigated. Although there are manystudies of plasma in liquids, generation of plasma in a cell culture medium has
not been reported. In this study, to reveal plasma-emission species and effect oforganic compounds in a culture medium, we investigated the spectrum ofplasma emission, OH intensity and H2O2 concentration by comparing with theresults of chloride solutions. The spectra analysis showed little difference
between the cell culture medium and the chloride solutions. OH intensity andH2O2 concentration had a more relationship with electrical conductivity thanchloride species in liquids.

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

8aC-3
September 8th (Mon.), <10:30-11:45>
Room 3The Effect of Oxygen Concentration and Water Vapor
Evaporated from Agar on Spore Sterilization Using Plasma
Masayuki KOMATSU
The University of Tokyo

Abstract:
The effects of oxygen concentration and water vapor evaporated fromagar medium on plasma sterilization of spore are examined. A nanosecond
pulsed streamer discharge is used. The sterilization rate increases withdecreased N2 gas flow rate. It indicates that reactive species produced fromwater vapor evaporated from the agar medium, such as OH and H2O2, sterilizes
the spore because the humidity on the agar medium due to the evaporated
water from the agar medium increases with the decreased N2 gas flow rate. The
spore is also sterilized by O3. The sterilization area by O3 is much wider thanthat by the reactive species from H2O.

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

8aC-4
September 8th (Mon.), <10:30-11:45>
Room 3Inactivation of microorganisms on the spherical solid surface
with DBD
Takuya ARISAKA, Takanori TANINO and ○Takayuki OHSHIMA
Graduated School of Engineering, Gunma University

Abstract:
Inactivation of microorganism on the surfaces, such as a soybean andrice, is important in food engineering.
In this research, we used a biodegradable plastic sphere, which has
6 mm in diameter, as a food solid model. The plastic spheres of 25 g wereimmersed in Aspergillus niger or Bacillus subtilis spore suspension, and dried atroom temperature overnight. The cell concentration of A. niger and B. subtilis
spore suspension were 1.0×108 CFU/mL and 1.0×106 CFU/mL, respectively.
The electric discharge unit consisted of the silica glass board and the aluminum
two tapes, and AC high voltage (6.2 kVp and30kHz) was applied to the aluminum tape. DBD (Dielectric BarrierDischarge) was generated between the aluminum tapes. The electricdischarge unit was put on a rotary shaker (75 rpm), and survival ratios weremeasured before and after DBD treatment. In the case of A. niger, the survival
ratio after DBD treatment of 30 min was 10-5. This system was useful for theinactivation of mold on the solid surface. However, it was hard to inactivate B.
subtilis spore with our system. It is thought that expansion of discharging spaceand protraction of contact time are required in order to inactivate B. subtilis
spores.