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Static magnetic filed was superimposed for surface tension measurement of molten silicon by oscillating droplet method using ElectroMagnetic Levitation (EML). Amplitude of surface oscillation of the m = 0, +/-1 and +/-2 was attenuated with increasing the static magnetic field from 0 to 0.3 T. When the static magnetic field was above 0.4 T, the surface oscillations of m = 0 and +/-1 vanished, whereas only the m = +/-2 oscillation remained at 0.4 - 0.8 T. The oscillation frequencies of m = 0 and +/-1 were increased with increasing static magnetic field, whereas that of m = +/-2 oscillation was constant at 0 - 0.3 T. Although the frequency of the m = +/-2 oscillation became a slightly small at 0.4 T, it kept constant again at 0.4 - 0.8 T. The calculated surface tension of molten silicon was influenced by the static magnetic field. Superimposition of static magnetic filed to EML is not equivalent to the microgravity experiment., 資料番号: AA0063706010

Microgravity conditions have advantages of measurement of the surface tension and the viscosity of metallic alloys by the oscillating drop method with an ElectroMagnetic Levitation (EML) device. However, in Japan we have no facilities of measurement of these thermophysical properties of high temperature melts under microgravity conditions. Therefore, we rearrange the Parabolic Flight Levitation Experiment Facility (PFLEX) devices for measurements of thermophysical properties of them under the microgravity conditions. We succeeded to measure surface oscillation of levitated liquid droplets using PFLEX on bad flight experiments performed from September 17-29, 2007 operated by DAS (Diamond Air Service). In these experiments, we obtained not only the thermophysical properties of Cu melts but the effects of electromagnetic force for levitation on the surface oscillation. Base on this result, we are planning next parabolic flight experiments to study of oxygen effects on surface tension, and also to perform more precise measurements of surface oscillation in order to improve analysis method the surface oscillation spectra. If we will succeed this approach, we will be able to measure high temperature, reactive alloys such as Ti based alloys which is planning to use next generation materials for turbine brads of the jet engine and the power plants., 資料番号: AA0063706007

It is significant to measure surface tension and its temperature under microgravity in an ambient atmosphere with various oxygen partial pressures as a function of temperature, from the view point of both industry application and science of high temperature melts. Measurement will be carried out using the electromagnetic levitator on board the Gulfstream., 資料番号: AA0063706002

Levitation is an elegant method to measure thermophysical properties of high temperature melts, such as molten semiconductors, molten steel and so on. The effect of applying magnetic field and use of microgravity environment are compared. We propose measurement of surface tension by electromagnetic levitation in an atmosphere with various oxygen partial pressures in microgravity on board the airplane under the collaboration with European scientists in a the frame work of collaboration program 'JAXA-ESA Topical Team'., 資料番号: AA0063349043

A static magnetic field up to 1.0 T was superimposed to silicon droplet levitated by electromagnetic force. The influences of the superimposition of the static magnetic field on the surface oscillation of the droplet were investigated. Surface oscillation of m = 0, +/- 1, and +/- 2 modes was attenuated vanishingly above 0.5 T. Although another oscillation like m = +/- 2 mode still remained under the static magnetic field from 0.5 to 0.8 T, an analysis of a deflection angle for the elliptically deformed droplet showed that it was due to the rotation., 資料番号: AA0063349038

第25回宇宙利用シンポジウム(2009年1月14日-15日, 宇宙航空研究開発機構宇宙科学研究本部相模原キャンパス), The Twenty-fifth Space Utilization Symposium (January 14-15, 2009: ISAS/JAXA Sagamihara, Japan), The electromagnetic levitator for microgravity condition called PFLEX (Parabolic Flight Levitation Experiment Facility) was improved for precision measurement of surface tension of high temperature melt. We succeeded in the electromagnetic levitation of molten copper during the parabolic flight regardless of the gravitational change from 1.5 G to micro G. Several peaks were observed in the frequency spectrum for the surface oscillation of the molten copper, the spectrum becomes simple under micro G due to the release of the external force from gravitational acceleration and electromagnetic force., 資料番号: AA0064297085

An identification of frequencies of the m = +/-2 oscillation is required to measure an accurate surface tension of high temperature by the oscillating droplet technique using electromagnetic levitation. However, it is very difficult because the frequency peak of the m = 2 oscillation splits into two peaks in the frequency analysis if the droplet rotates. In this study, we clarified the influence of the droplet rotation on the m = +/-2 oscillation in the frequency analysis considering initial phase difference between m = +2 and m = -2., 資料番号: AA0063706009