TEION KOGAKU (Journal of Cryogenics and Superconductivity Society of Japan)

Four film boiling modes including the silent film boiling and the noisy film boiling were discriminated experimentally. Each mode was classified through visual observation and transient pressure and temperature measurements near the heater. It was found that in subcooled He II there were two film boiling modes, which are the strongly subcooled and weakly subcooled film boiling modes. The variation of boiling state between these two modes could be visually observed well by use of a transparent heater. All mode of film boiling is clearly mapped in diagrams as a function of pressure, temperature and heat flux. It is elucidated that the existence of He I layer influences the development of the vapor layer. (Translation of the article originally published in Cryogenics 49 (2009) 583–588)

View full abstract

Show abstractHide abstract

The uncertainty of AC loss measurements for multifilamentary superconducting wires by a pickup coil method is evaluated on the basis of the law of propagation of uncertainty. In this evaluation, the effects of measurement conditions, signal processing, and the division of the AC loss into its components (hysteresis loss and coupling loss) are taken into account as ele-ments of uncertainty. The effect of the measurement conditions is evaluated using theoretical expressions of the two main compo-nents. Additionally, the effect of signal processing is considered in accordance with the actual processes of the AC loss measure-ment using experimental outputs. The main factors that contribute to the uncertainty in the propagation process are discussed. The estimated resultant uncertainties are compared to experimental ones for round robin tests of AC loss measurement of Nb-Ti multi-filamentary wires exposed to an alternating transverse magnetic field. (Translation of the article originally published in Cryogen-ics 50 (2010) 111–117)

View full abstract

Download PDF (331K)

Register with J-STAGE for free!