25 research outputs found
Assessing Vegetation Resistace from Observed Temporal Water Surface Profiles of Flood Flows in Rivers
Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv
アーベリアン射影におけるゲージ依存性について
取得学位:博士(理学),学位授与番号:博乙第204号,学位授与年月日:平成12年3月22日,学位授与年:200
Gauge independence of Abelian and monopole dominance
We formulate a stochastic gauge fixing method to study the gauge dependence
of Abelian projection. In this method, one can change the gauge from the
maximally Abelian one to no gauge fixing continuously. We have found that the
linear part of the heavy quark potential from Abelian contribution depends
little on the gauge parameter. Similar results have been obtained for the
monopole contribution part.We also investigate the gauge dependence of the
length of monopole loop, which is known to be important for the confinement,
and monopole density. These results suggest that the picture that monopole
plays an important role for the confinement of QCD dose not depend on choice of
the gauge.Comment: Lattice 2000 (Topology), 4 pages, 7 figures, LaTe
Numerical Simulation of Flat-to-slant Ductile Fracture Transition in Notched Plate
AbstractThe effort of this study is to develop a damage model for simulating large ductile crack extension accompanied by a flat and a slant surface observed in the hydrostatic full-scale tests up to rupture for API X80 line pipes with an axial through-wall notch. A small and thin specimen with a shallow through-thickness notch having a large ligament (sub-sized Charpy V-notch (Sub-CVN) specimen subjected to 3-point bending) is used for a fundamental verification study. The Sub-CVN specimen provided the similar macroscopic process as well as micro-mechanism for ductile cracking, where a flat-to-slant fracture transition accompanied by a transition from an equi-axed dimple mode to a shear-slip mode fracture is presented. On the basis of the observed mechanism of ductile crack growth, a numerical ductile damage model for predicting the large ductile crack growth resistance is proposed taking into account an effect of the Lode parameter on ductile fracture into the present damage model proposed by authors. The crucial consideration is that the damage parameters to be identified can be correlated to the material properties. In this model, the shear-dominated stress state is assumed to advance the acceleration of damage evolution due to a shear localization mechanism at lower damage level even at the same stress triaxiality condition, so that the critical damage fraction dependent on the Lode parameter is phenomenologically employed in this model. The modified damage model reproduces the same ductile crack profile together with the same micro-mechanisms for forming the chevron-shaped flat surface as those observed in the experiment. The possibility to reproduce the flat-to-slant fracture transition is also demonstrated by the simulation
Nf=1 QCD simulation with improved gauge action at finite temperature
We study the deconfinement transition of QCD by the hybrid Monte
Carlo algorithm with Wilson fermions. We calculate the Polyakov loop, its
susceptibility and Binder cumulant and use the method to locate the
phase transition point. Our results are similar to the previous results
obtained by the multiboson algorithm.Comment: 3 pages, 3 figures: Lattice2003(Non-zero temperature and density
Three topics of monopole dynamics in abelian projected QCD
Three topics about monopole dynamics after abelian projection are reported.
The first is the new and detailed analyses of monopole action obtained
after the block-spin transformation on the dual lattice. The
dependence for all couplings are well fitted with a universal curve. The
distance dependence of the couplings is well reproduced by a massive propagator
with the mass in unit of . The second is the monopole action
recently obtained. The third is new interesting gauges showing abelian and
monopole dominances as in the maximally abelian gauge.Comment: Talk presented at LATTICE96(topology), 4 Pages, 7 eps figure
Recent topics of infrared effective lattice QCD
Three topics concerning infrared effective lattice QCD are discussed.
(1)Perfect lattice action of infrared SU(3) QCD and perfect operators for the
static potential are analytically given when we assume two-point monopole
interactions alone. The assumption seems to be justified from numerical
analyses of pure SU(3) QCD in maximally abelian gauge. (2)Gauge invariance of
monopole dominance can be proved theoretically if the gauge invariance of
abelian dominance is proved. The gauge invariance of monopole condensation
leads us to confinement of abelian neutral but color octet states after abelian
projection. (3)A stochastic gauge fixing method is developed to study the gauge
dependence of the Abelian projection, which interpolates between the maximally
abelian (MA) gauge and no gauge fixing. Abelian dominance for the heavy quark
potential holds even in the gauge which is far from Maximally Abelian one.Comment: LATTICE99(Poster),3 pages, LaTeX with 4 eps figure
The K computer Operations: Experiences and Statistics
AbstractThe K computer, released on September 29, 2012, is a large-scale parallel supercomputer system consisting of 82,944 compute nodes. We have been able to resolve a significant number of operation issues since its release. Some system software components have been fixed and improved to obtain higher stability and utilization. We achieved 94% service availability because of a low hardware failure rate and approximately 80% node utilization by careful adjustment of operation parameters. We found that the K computer is an extremely stable and high utilization system