Computational procedure for finite difference solution of one-dimensional heat conduction problems reduces computer time

Computational procedure reduces the numerical effort whenever the method of finite differences is used to solve ablation problems for which the surface recession is large relative to the initial slab thickness. The number of numerical operations required for a given maximum space mesh size is reduced

Bound States of (Anti-)Scalar-Quarks in SU(3)_c Lattice QCD

Light scalar-quarks \phi (colored scalar particles or idealized diquarks) and their color-singlet hadronic states are studied with quenched SU(3)_c lattice QCD in terms of mass generation. We investigate ``scalar-quark mesons'' \phi^\dagger \phi and ``scalar-quark baryons'' \phi\phi\phi as the bound states of scalar-quarks \phi. We also investigate the bound states of scalar-quarks \phi and quarks \psi, i.e., \phi^\dagger \psi, \psi\psi\phi and \phi\phi\psi, which we name ``chimera hadrons''. All the new-type hadrons including \phi are found to have a large mass due to large quantum corrections by gluons, even for zero bare scalar-quark mass m_\phi=0 at a^{-1}\sim 1{\rm GeV}. We conjecture that all colored particles generally acquire a large effective mass due to dressed gluon effects.Comment: Talk given at The 17th International Spin Physics Symposium (SPIN2006), Kyoto, Japan, 2-7 Oct 200

Detection of flux emergence, splitting, merging, and cancellation of network field. I Splitting and Merging

Frequencies of magnetic patch processes on supergranule boundary, namely flux emergence, splitting, merging, and cancellation, are investigated through an automatic detection. We use a set of line of sight magnetograms taken by the Solar Optical Telescope (SOT) on board Hinode satellite. We found 1636 positive patches and 1637 negative patches in the data set, whose time duration is 3.5 hours and field of view is 112" \times 112". Total numbers of magnetic processes are followed: 493 positive and 482 negative splittings, 536 positive and 535 negative mergings, 86 cancellations, and 3 emergences. Total numbers of emergence and cancellation are significantly smaller than those of splitting and merging. Further, frequency dependences of merging and splitting processes on flux content are investigated. Merging has a weak dependence on flux content only with a power- law index of 0.28. Timescale for splitting is found to be independent of parent flux content before splitting, which corresponds to \sim 33 minutes. It is also found that patches split into any flux contents with a same probability. This splitting has a power-law distribution of flux content with an index of -2 as a time independent solution. These results support that the frequency distribution of flux content in the analyzed flux range is rapidly maintained by merging and splitting, namely surface processes. We suggest a model for frequency distributions of cancellation and emergence based on this idea.Comment: 32 pages, 10 figures, 1 table, accepted to Ap

Surface damage resulting from rolling contact operating in magnetic field

This paper describes the effects of magnetic field in rolling contact tests of steel by using a two-disc configuration and the investigation of mechanisms involved. Two contact conditions, namely pure rolling and rolling with 10% sliding were used together with 0.4 and 1.1 Tesla horizontal static magnetic fields created by permanent magnets. Results of optical and scanning electron microscope observations point out that finer wear particles and smoother worn surfaces are produced in the presence of a magnetic field. It is proposed that finer wear particles result from the movement of subsurface crack initiation towards the surface due to the action of magnetic field

Single domain YBCO/Ag bulk superconductors fabricated by seeded infiltration and growth

We have applied the seeded infiltration and growth (IG) technique to the processing of samples containing Ag in an attempt to fabricate Ag-doped Y-Ba-Cu-O (YBCO) bulk superconductors with enhanced mechanical properties. The IG technique has been used successfully to grow bulk Ag-doped YBCO superconductors of up to 25 mm in diameter in the form of single grains. The distribution of Ag in the parent Y-123 matrix fabricated by the IG technique is observed to be at least as uniform as that in samples grown by conventional top seeded melt growth (TSMG). Fine Y-211 particles were observed to be embedded within the Y-123 matrix for the IG processed samples, leading to a high critical current density, Jc, of over 70 kA/cm2 at 77.3 K in self-field. The distribution of Y-211 in the IG sample microstructure, however, is inhomogeneous, which leads to a variation in the spatial distribution of Jc throughout the bulk matrix. A maximum-trapped field of around 0.43 T at 1.2 mm above the sample surface (i.e. including 0.7 mm for the sensor mould thickness) is observed at liquid nitrogen temperature, despite the relatively small grain size of the sample (20 mm diameter × 7 mm thickness)