Ethylene gas was decomposed using packed-bed type dielectric barrier discharge (PBDBD) plasma reactor to keep freshness of fruits. The ethylene gas was diluted with gas mixture of nitrogen, oxygen and carbon dioxide as simulated gas in the transportation container. The PBDBD plasma was generated by a pulse switching power supply which consisted of MOS-FET switching devices, capacitors and pulse transformers. The Ag nanoparticle-loaded zeolite as catalyst has high activity and good performance for reduction of ozone and oxidizing carbon monoxide at room temperature. The Ag nanoparticle-loaded zeolite pellets enhanced ethylene removal efficiency and reduced ozone and carbon monoxide produced by the plasma treatment. It was confirmed that the carbon monoxide in the gas simulated dry air composition was oxidized using Ag nanoparticle-loaded zeolite with plasma treatment.

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In this research effects of pulsed power applications to Gladiolus bulb on germination, growth and dormancy breaking were investigated. The peak voltage, pulse width and repetition rate were 20 kV, 300 ns and 2 pps, respectively. The deposited energy density to bulb is approximately 6.5 mJ/g for one pulse. From the experiments optimum number of application for germination was found to be 10 times, it corresponds to a total deposited energy density of 59 mJ/g. Even if no water incubation the germination was confirmed after application. It suggest that the pulsed power application results in expression of germination gene. The germination ratio in intensive applications into one place were compared with that in dispersive applications. Higher germination ratio was obtained at dispersive applications. The reason for that is damages of bulb was reduced due to the decrease of deposited energy density. From experiments using dormant bulbs it was found that the pulsed power application can break the dormancy.

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A large number of micro bubbles are generated by injection of a pulsed power (0.41 MW, 1 µs [FWHM]) into water solution with 5.7-wt% sodium hydrogen carbonate (NaHCO₃) as an additive. The diameter of the bubbles is estimated to be 23 µm which is half of that obtained without the additive. The number density of the bubbles with the additive is 6 times as high as that obtained without the additive. We found that 98 % of the larva of Artemia (brine shrimp) are successfully inactivated by firing 800 injections of pulsed power into water solution with the additive, which is 1.6 times as high as that obtained for the water solution without the additive. The gross energy efficiency for inactivation reaches 0.25 million larvae a kWh. It indicates that a large number of micro bubbles generated by the injection of pulsed power are effective to inactivate the zooplankton in the water.

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It is said that the sterilization by pulsed electric field occurs by pores generated by dielectric breakdown of cell membranes. In the paper, we have discussed what factor by the electric field has generated electric discharge on a cell membrane of bacteria and has been dominant for the sterilization ratio. The dominant factor generating the discharge on the cell membrane has been indicated by organizing the relationship between the condition applying the pulse electric field and the sterilization ratio. As the result, it has been shown that the energy consumption in the membrane of bacteria has worked dominantly in sterilization. It shows the possibility that thermal breakdown takes place by the Joule heat generated by the energy that is consumed in the cell membrane. This result is evidence that electrical breakdown is dominant factor for sterilization in PEF.

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The mechanism of the growth enhancement effect of plants induced by a low-pressure oxygen plasma is investigated. The growth enhancement of plants would be caused by the regulation of the antioxidative activity in plants. Antioxidative activities in seeds and stems of radish sprouts are varied by a low-pressure oxygen plasma irradiation. The thiol compounds amount in seeds of radish sprouts, which relates to the antioxidative activity, has the same tendency as the active oxygen amount in a low-pressure oxygen plasma. Major active oxygen species controlling the antioxidative activity and the thiol compounds amount in radish sprouts would be the singlet excited oxygen molecule, which is revealed by the light emission intensity at 762 nm.

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Effects of electrical stimulation on yield of Agitake mushroom (Pleurotus jp takizawa) in sawdust-bed cultivation using high voltage pulses were investigated experimentally. The pulsed voltage was applied to the sawdust-bed using a high-voltage generator based on Cockcroft-Walton circuit. The input energy was controlled by number of the high-voltage pulse applying to the sawdust-bed. The experimental results showed that the yield of fruit body increased to be 2.0 times larger by applying high-voltage pulses at 0.68 J (30 kV, 60 times applying voltage) input energy. The increment of the yield by applying voltage had maximum at optical input energy.

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Incubation rate of zooplankton (Artemia Salina) eggs irradiated with pulsed intense relativistic electron beam (PIREB) is studied in the air. The PIREB with a kinetic energy of up to 6MeV, a peak current of -0.5kA and pulse duration of 80ns (FWHM) is generated by using the pulsed power generator ETIGO-III. The incubation rate of zooplankton eggs reduced to 31% after a shot of PIREB irradiation in comparison with one of 79% without PIREB irradiation. The incubation rate reduced up to 1% after 3 shots of PIREB irradiation.

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In this study, we propose a new treatment method to sanitize ballast water contaminated with plankton and/or bacteria. This method is constituted of water cavitation and discharge plasma in this cavitation field. The 0.5% brackish water containing brine shrimp (2.5×10⁴ and 1.25×10⁵ m^-3) was treated in 60 s. Then, we saw no surviving plankton in the treated water. Similarly, the treatment of water containing Escherichia coli cells (4×10¹⁵ m^-3) in 120 s completed the sterilization. We also observed the DNA damage and destruction of the cellular morphology after treatment. It seems that the mechanisms of sterilization are radical reactions and physical damage caused by shockwave, and radical reactions are dominant mechanism.

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A compact pulsed power device was proposed and constructed for plasma interaction experiments relevant to astrophysical phenomena using a configuration of counter-streaming high-speed plasma flows. A controllable, high-speed argon plasma flow with a drift velocity of ∼ 20km/s, an ion density of 10¹³cm^-3, an electron temperature of ∼ 1eV, and a pulse length of a few microseconds was obtained using tapered z-pinch discharge. Plasma interaction experiments were carried out at high-acoustic-Mach number regime (M_i∼ 10) in which ion-ion collision was negligible. An enhancement of line emission and a decrease of probe current were observed in the interaction region of counter-streaming plasmas. These results indicate that the ion flow decelerated even without momentum transfer due to ion-ion collisions.

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As a sterilization technique, the hydrogen peroxide plasma sterilization is generally used. The hydrogen peroxide plasma sterilization can not be used in food sterilization for the use of toxic hydrogen peroxide. Example of other sterilization techniques, the atmospheric pressure plasma sterilization has been attempted. By the way, studies have been attempted for application to sterilization techniques of PBII technology. Application to medical equipment is considered, because it uses harmless nitrogen or oxygen gas to sterilization using PBII. Sterilization using PBII is possible processing a short time at low temperatures.  In this study, using the PBII sterilization technique using a harmless gas, the authors tried the application to the sterilization of food. Therefore, the authors examined the plasma generation technology suitable for the sterilization process by the measurement of the spectrum. Increase in the number of ions in the plasma was observed with the combination of RF burst plasma and self-ignited plasma. The authors evaluated sterilization processing by the number of living bacteria of the spore bearing bacterium about only self-ignition plasma and the combination of RF burst plasma and self-ignited plasma.

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The plasma fluid flow with the propagation of laser-supported detonation (LSD) in a pulsed-laser-driven MHD electrical power generator has been examined with a time-dependent two-dimensional numerical simulation, and the performance has been evaluated for the different incident direction of laser and for various generator shapes. Both the direct propagation of LSD through the generator and the high temperature and pressure gas flow produced by LSD in the upper-outside region of the generator contribute to the power generation. The supersonic flow realized in the generator with a throat can lead a higher enthalpy extraction ratio with a longer duration time of power generation.

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