Effective resistance of current-carrying superconducting wire in oscillating magnetic fields 1: Single core composite conductor

The influence of oscillating magnetic fields on the dc transport current in a single core superconducting wire has been studied by observing the terminal voltage of the wire. The voltage versus oscillating field characteristics can be explained quantitatively by a theoretical analysis based on the critical state model. The analysis shows that the voltage measurement gives detailed information on the change of the distribution of the magnetic induction inside the superconductor. An effective resistance appears in the transport current loop when the amplitude of the oscillating field exceeds a certain threshold value. The dependence of the effective resistance on the amplitude and frequency of the oscillating field and on the conductor diameter is discussed.     

Pulsed field loss characteristics of the Japanese test coil for the large coil task

This paper describes some results of an analytical calculation and the measurements of a pulsed field loss on the Japanese LCT conductor. The conductor, whose aspect ratio is around 2.5, is wound edge wise to reduce the pulsed field loss. The Japanese LCT coil, with the conductor thus designed, was evaluated to have a pulsed field loss of about 19W. This includes the loss of the helium vessel under the normal LCT test with a pulsed field of 0 to 0.14T. In addition, the loss measurement has been carried out up to 25 T/s. Measured results on the relation between the loss of a single strand and that of a whole strand pack well supports the validity of the loss analysis which includes a newly arranged set of analytical equations.     

Isolation of dimethyl sulfone-degrading microorganisms and application to odorless degradation of dimethyl sulfoxide

With the objective of developing an odorless biodegradation process for dimethyl sulfoxide (DMSO), Hyphomicrobium sp. WU-OM3 was isolated. During the cultivation of strain WU-OM3 cells with 20 mM dimethyl sulfone (DMSO2) as the sole carbon source, DMSO2 was completely consumed within 48 h and sulfate ion accumulated in the culture broth. Methanesulfonate was also detected as an intermediate of DMSO2 degradation. By combining the DMSO-oxidizing microorganism and strain WU-OM3 cells, 0.64 mM (50 mg/l) DMSO was degraded to sulfate ion with 80% molar conversion ratio.     

Trading variance reduction with unbiasedness: the regularized subspace information criterion for robust model selection in kernel regression

A well-known result by Stein (1956) shows that in particular situations, biased estimators can yield better parameter estimates than their generally preferred unbiased counterparts. This letter follows the same spirit, as we will stabilize the unbiased generalization error estimates by regularization and finally obtain more robust model selection criteria for learning. We trade a small bias against a larger variance reduction, which has the beneficial effect of being more precise on a single training set. We focus on the subspace information criterion (SIC), which is an unbiased estimator of the expected generalization error measured by the reproducing kernel Hilbert space norm. SIC can be applied to the kernel regression, and it was shown in earlier experiments that a small regularization of SIC has a stabilization effect. However, it remained open how to appropriately determine the degree of regularization in SIC. In this article, we derive an unbiased estimator of the expected squared error, between SIC and the expected generalization error and propose determining the degree of regularization of SIC such that the estimator of the expected squared error is minimized. Computer simulations with artificial and real data sets illustrate that the proposed method works effectively for improving the precision of SIC, especially in the high-noise-level cases. We furthermore compare the proposed method to the original SIC, the cross-validation, and an empirical Bayesian method in ridge parameter selection, with good results.     

Wind-flow measurement over the Subaru Telescope

Wind flows over the 8.2-m Subaru Telescope at Mauna Kea in Hawaii were analyzed with a correlation method. Three or four wind flows were detected from our measurements. Spatial and temporal resolution of the wind-flow analysis across the 8.2 m pupil were investigated experimentally. A three-dimensional spatiotemporal-frequency analysis was also applied to the wind-flow data.     

Solid-Liquid Interface Motion of 4He in an Acoustic Field

When acoustic waves were applied to the solid-liquid interface of ⁴He perpendicularly, from the solid side, the solid was megted at high temperatures and grown at low temperatures. This means that the direction of the force on the interface was inverted at an inversion temperature, T _i. We attributed this effect to the acoustic radiation pressure, which induced crystallization and megting [Phys. Rev. Lett. 90, 075301, (2003)]. Temperature dependence of the interface motion by acoustic waves was investigated in several surface orientations. Anisotropy of T _i was found and T _i was lower on a vicinal surface than on a rough surface.     

Polymer film-type channel electron multipliers: Their characteristics and comparison with bulk-type flexible multipliers

Polymer film-type channel electron multipliers (CEMs) were developed and their characteristics investigated in comparison with bulk-type flexible CEM. As film-type CEMs, a paint-coating-type CEM and a solvent-etching-type CEM were fabricated. The paint-coating-type CEM is made by coating a “paint” which is prepared by dissolving in a solvent an electronically conductive polymeric composition having a high secondary electron emission yield. Up to the present study the mean gain of the film-type CEM, in spite of the lower resistivity of the dynode, seems to be slightly more dependent on the count rate than that of the bulk-type CEM made of the same material. However, the convenience of fabricating the dynode film by coating the dynode-forming paint on the internal surface of any shaped tube or a flexible polymer tube would overcome the slight disadvantage mentioned above.     

Bioconversion of n−3 and n−6 PUFA by <Emphasis Type="Italic">Clavibacter</Emphasis> sp. ALA2

Clavibacter sp. ALA2 oxidized n−3 and n−6 PUFA into a variety of oxylipins. Structures of products converted from EPA and DHA were determined as 15,18-dihydroxy-14,17-epoxy-5(Z),8(Z),11(Z)-eicosatrienoic acid and 17,20-dihydroxy-16,19-epoxy-4(Z),7(Z),10(Z),13(Z)-docosatetraenoic acid by GC-MS and NMR analyses. In contrast, γ-linolenic acid and arachidonic acid were converted to diepoxy bicyclic FA, tetrahydrofuranyl monohydroxy FA, and trihydroxy FA. Thus, the structures of bioconversion products were different between n−3 and n−6 PUFA. Furthermore, strain ALA2 placed hydroxy groups and cyclic structures at the same position from the ω-terminal despite the number of carbons in the chain and the double bonds in the PUFA.     

Tensile creep behavior of 3-D woven Si-Ti-C-O fiber/SiC-based matrix composite with glass sealant

The present work investigates the tensile creep behavior (deformation and rupture) at 1100–1300°C in air of a 3-D woven Si-Ti-C-O (Tyranno) fiber/SiC-based matrix composite with and without glass sealant. The composite contained Si-Ti-C-O fibers with an additional surface modification in order to improve interface properties. Although a significant decrease in tensile strength was observed in the unsealed composite beyond 1000°C in air (and attributed to oxidation of the fiber/matrix interface), the composite with glass sealant possessed excellent mechanical properties for short-term (<1 hr.) exposure in air. In this study, tensile creep testing was conducted at 1100–1300°C in air and the effect of glass sealant on medium- and long-term strength was investigated. In addition, chemical stability of the glass sealant was evaluated by X-ray diffraction analysis (XRD) and energy dispersive X-ray spectrometer (EDS). The creep rupture behavior of the composite with glass sealant under long-term exposure is suggested to depend on several factors including decomposition, evaporation, and crystallization of the glass sealant material, in addition to the applied stress.