13,269 research outputs found
Evaluation of primary water stress corrosion cracking growth rates by using the extended finite element method
AbstractBackgroundMitigation of primary water stress corrosion cracking (PWSCC) is a significant issue in the nuclear industry. Advanced nickel-based alloys with lower susceptibility have been adopted, although they do not seem to be entirely immune from PWSCC during normal operation. With regard to structural integrity assessments of the relevant components, an accurate evaluation of crack growth rate (CGR) is important.MethodsFor the present study, the extended finite element method was adopted from among diverse meshless methods because of its advantages in arbitrary crack analysis. A user-subroutine based on the strain rate damage model was developed and incorporated into the crack growth evaluation.ResultsThe proposed method was verified by using the well-known Alloy 600 material with a reference CGR curve. The analyzed CGR curve of the alternative Alloy 690 material was then newly estimated by applying the proven method over a practical range of stress intensity factors.ConclusionReliable CGR curves were obtained without complex environmental facilities or a high degree of experimental effort. The proposed method may be used to assess the PWSCC resistance of nuclear components subjected to high residual stresses such as those resulting from dissimilar metal welding parts
Charged Rotating Black Holes on DGP Brane
We consider charged rotating black holes localized on a three-brane in the
DGP model. Assuming a -symmetry across the brane and with a stationary and
axisymmetric metric ansatz on the brane, a particular solution is obtained in
the Kerr-Schild form. This solution belongs to the accelerated branch of the
DGP model and has the characteristic of the Kerr-Newman-de Sitter type solution
in general relativity. Using a modified version of Boyer-Lindquist coordinates
we examine the structures of the horizon and ergosphere.Comment: LaTeX, 15 pages, Discussion on a bulk solution is adde
Large-scale filamentary structures around the Virgo cluster revisited
We revisit the filamentary structures of galaxies around the Virgo cluster,
exploiting a larger dataset based on the HyperLeda database than previous
studies. In particular, this includes a large number of low-luminosity
galaxies, resulting in better sampled individual structures. We confirm seven
known structures in the distance range 4~~Mpc~ SGY~ 16~
Mpc, now identified as filaments, where SGY is the axis of the supergalactic
coordinate system roughly along the line of sight. The Hubble diagram of the
filament galaxies suggests they are infalling toward the main-body of the Virgo
cluster. We propose that the collinear distribution of giant elliptical
galaxies along the fundamental axis of the Virgo cluster is smoothly connected
to two of these filaments (Leo~II~A and B). Behind the Virgo cluster
(16~~Mpc~ SGY~ 27~~Mpc), we also identify a new filament
elongated toward the NGC 5353/4 group ("NGC 5353/4 filament") and confirm a
sheet that includes galaxies from the W and M clouds of the Virgo cluster ("W-M
sheet"). In the Hubble diagram, the NGC 5353/4 filament galaxies show infall
toward the NGC 5353/4 group, whereas the W-M sheet galaxies do not show hints
of gravitational influence from the Virgo cluster. The filamentary structures
identified can now be used to better understand the generic role of filaments
in the build-up of galaxy clusters at z~~0.Comment: 8 pages, 4 figures, accepted for publication in Ap
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