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We have been studied the sterilization of liquid using high electric field pulse. In this paper, we report the effect of temperature on survival rate in high electric field pulse sterilization. The sample was liquid medium including E. coli (JM103). Experiments were carried out at two temperatures region, room temperature region (18∼25 °C) and low temperature region (2∼5°C). Effect of pulse interval between successive pulses was also examined at 60sec and 120sec. We obtained the results as follows: 1. The survival rate at low temperature region was higher than that at room temperature region. The low flexibility of cell membrane at low temperature is considered to be responsible for the high survival rate, because the stiff cell membrane has high resistivity against mechanical deformation due to the pulse shaped Maxwell stress. 2. At room temperature region, the survival rate after 50 pulses decreased to 0.69×10−3 for 120sec interval ∼ 2.9×10−3 for 60sec interval. These rates clear a hygiene standard in Japan of 1.0×10−2 for milk sterilization at 63°C for 30 minutes. 3. At low temperature region, the survival rate after 50 pulses stayed at the level of 1.2×10−2 for 60sec interval ∼ 7.4×10−2 for 120sec interval. [ABSTRACT FROM PUBLISHER]

Electric double layer (EDL) is a kind of interfacial phenomenon. The Phenomenon is known to have huge capacitance. The purpose of the present study is analysis of behavior of ions in electric double layer. For this purpose, we measured capacitance of EDL in 5 wt% NaCl solution at room temperature using step voltage and ramp voltage. We also observed characteristics of EDL at low temperature. We obtained following results. The capacitance by the ramp voltage is about ten times larger than that by the step voltage. EDL is kept in frozen NaCl solution after short-circuiting. Capacitance of frozen EDL is larger than that of liquid EDL at room temperature. [ABSTRACT FROM PUBLISHER]

In recent year, the improvement of efficiency of electric power apparatus is required because the environmental and energy problem is serious. Thus, the development of superconducting power apparatus has been proceeded. Glass Fiber Reinforced Plastics (GFRP) is widely used as electrical insulating material in superconducting power apparatus. However, GFRP gives heavy load to environment when scrapped because it is not recycled, nor naturally decomposed. We pay attention to combination of natural fiber and ice as electrical insulating material at cryogenic temperature. Both natural fiber and ice are environment-friendly material. A.C. breakdown strength of ice is degraded if void or crack exists. Thus, we used bamboo or kenaf fiber to prevent formation of void or crack. We had confirmed A.C. breakdown strength of the composite system of bamboo-ice or kenaf fiber-ice is comparable to GFRP laminated board at 77K. We consider that mixture of water soluble material and water may prevent formation of void or crack, and improve A.C. breakdown strength of the composite system. We examined A.C. breakdown strength of ice-glycerin mixed system at 77K. As a result, it is suggested that mixture of glycerin increases A.C. breakdown strength of ice at 77K. [ABSTRACT FROM PUBLISHER]

Silicone rubber (SiR) has various excellent characteristics, and is widely used in various apparatus as insulating material. However, tree initiation processes and degradation phenomena in SiR are not clear. The investigations of tree initiation processes at high electric field region are very important. In this paper, the effect of H2O on electrical tree initiation voltage will be examined. Three kinds of samples were tested; untreated SiR, SiR treated by vacuum heating, and SiR impregnated with liquid water after vacuum heating treatment. The tree initiation voltage of SiR treated by vacuum heating was higher than that of untreated SiR. It is considered that the tree initiation voltage is increased by removing gaseous H2O molecules. However the tree initiation voltage of SiR impregnated with liquid water after vacuum heating was higher than that of SiR treated by vacuum heating. These results seem to contradict each other. We consider that the tree initiation voltage is increased by presence of liquid H2O. It is suggested that the states of H2O molecules included in the free volume have a large effect on ac tree initiation in SiR. [ABSTRACT FROM PUBLISHER]

The influence of AC electric field on the growth of thale cress was studied. The seeds of thale cress were cultivated under two circumstances; one was under the AC 60Hz electric field of 2.5kV/m, and the other was under no electric field. They were grown for four or eight days, and the seed germination rate was counted every day, and stem length was measured on the fourth and the eighth day. We have confirmed the following things; (1) AC electric field accelerates the seed germination of thale cress. (2) The AC electric field accelerates the stem growth of thale cress. These results are similar to the effects of DC electric field on plant growth, however, the effects of the AC field are smaller than those of DC field. [ABSTRACT FROM PUBLISHER]

We have studied the influence of D.C. electric field on plant growth. Raphanus sativus longipinnatus (daikon radish) and Arabidopsis thaliana (thale cress) were used as sample. Thale cress is widely used as one of the model organisms for studying plant sciences, because its genome has been already sequenced. In the previous paper, we had reported the following results for daikon radish: (a) The application of D.C. electric field improves the seed germination rate. (b) The D.C. electric field increases the length and the weight. (c) The D.C. electric field encourages the consumption of substances which is stored in the seed. The following results had been also reported for thale cress: (d) The D.C. electric field accelerates the seed germination. (e) The D.C. electric field exerts no effect on seed germination when the electric potential of the thale cress is grounded. It is expected that there is an optimum strength of D.C. electric field for plant growth acceleration. As the first step to seek the optimum strength, we adopted 2.5kV/m and 10.0kV/m. Namely, the seeds of thale cress were cultivated under D.C. electric field of 2.5kV/m and 10.0kV/m. As a result, the growth of the sample was more promoted by 10.0kV/m D.C. field than by 2.5kV/m D.C. field. [ABSTRACT FROM PUBLISHER]