31,923 research outputs found
Topological Complexity of Frictional Interfaces: Friction Networks
Through research conducted in this study, a network approach to the
correlation patterns of void spaces in rough fractures (crack type II) was
developed. We characterized friction networks with several networks
characteristics. The correlation among network properties with the fracture
permeability is the result of friction networks. The revealed hubs in the
complex aperture networks confirmed the importance of highly correlated groups
to conduct the highlighted features of the dynamical aperture field. We found
that there is a universal power law between the nodes' degree and motifs
frequency (for triangles it reads T(k)\proptok{\beta} ({\beta}
\approx2\pm0.3)). The investigation of localization effects on eigenvectors
shows a remarkable difference in parallel and perpendicular aperture patches.
Furthermore, we estimate the rate of stored energy in asperities so that we
found that the rate of radiated energy is higher in parallel friction networks
than it is in transverse directions. The final part of our research highlights
4 point sub-graph distribution and its correlation with fluid flow. For shear
rupture, we observed a similar trend in sub-graph distribution, resulting from
parallel and transversal aperture profiles (a superfamily phenomenon)
Magnetic properties of geometrically frustrated SrGd2O4
A study of the magnetic properties of the frustrated rare earth oxide SrGd2O4
has been completed using bulk property measurements of magnetization,
susceptibility and specific heat on single crystal samples. Two zero-field
phase transitions have been identified at 2.73 and 0.48 K. For the field, H,
applied along the a and b axes, a single boundary is identified that delineates
the transition from a low field, low temperature magnetically ordered regime to
a high field, high temperature paramagnetic phase. Several field-induced
transitions, however, have been observed with H || c. The measurements have
been used to map out the magnetic phase diagram of SrGd2O4, suggesting that it
is a complex system with several competing magnetic interactions. The
low-temperature magnetic behavior of SrGd2O4 is very different compared to the
other SrLn2O4 (Ln = Lanthanide) compounds, even though all of the SrLn2O4
compounds are isostructural, with the magnetic ions forming a low-dimensional
lattice of zigzag chains that run along the c axis. The differences are likely
to be due to the fact that in the ground state Gd3+ has zero orbital angular
momentum and therefore the spin-orbit interactions, which are crucial for other
SrLn2O4 compounds, can largely be neglected. Instead, given the relatively
short Gd3+-Gd3+ distances in SrGd2O4, dipolar interactions must be taken into
account for this antiferromagnet alongside the Heisenberg exchange terms.Comment: 10 pages, 9 figure
A millimeter wavelength interferometer spectrometer Final report
Millimeter wavelength interferometer spectrometer for geological measurement
Experimental and numerical studies of ferritic stainless steel tubular cross sections under combined compression and bending
An experimental and numerical study of ferritic stainless steel tubular cross sections under combined loading is presented in this paper. Two square hollow section (SHS) sizes—SHS 40×40×240×40×2 and SHS 50×50×250×50×2 made of Grade EN 1.4509 (AISI 441) stainless steel—were considered in the experimental program, which included 2 concentrically loaded stub column tests, 2 four-point bending tests, and 14 eccentrically loaded stub column tests. In parallel with the experimental investigation, a finite-element (FE) study was also conducted. Following validation of the FE models against the test results, parametric analyses were carried out to generate further structural performance data. The experimental and numerical results were analyzed and compared with the design strengths predicted by the current European stainless steel design code EN 1993-1-4 and American stainless steel design specification SEI/ASCE-8. The comparisons revealed that the codified capacity predictions for ferritic stainless steel cross sections under combined loading are unduly conservative. The deformation-based continuous strength method (CSM) has been extended to cover the case of combined loading. The applicability of CSM to the design of ferritic stainless steel cross sections under combined loading was also evaluated. The CSM was shown to offer substantial improvements in design efficiency over existing codified methods. Finally, the reliability of the proposals was confirmed by means of statistical analyses according to both the SEI/ASCE-8 requirements and those of EN 1990
An Extremal Chiral Primary Three-Point Function at Two-loops in ABJ(M)
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