One-neutron removal strength of 7He into 6He using the complex scaling method

We study the one-neutron removal strength of the 7He ground state, which provides us with the 6He-n component in 7He. The He isotopes are described on the basis of the 4He+Xn cluster model (X=1,2,3). The complex scaling method is applied to describe not only the Gamow resonances but also the nonresonant continuum states of valence neutrons, with the correct boundary condition of particle decays. The one-neutron removal strength of 7He into the unbound states of 6He is calculated using the complex-scaled Green's function, in which a complex-scaled complete set of 4He+n+n states is adopted. Using this framework, we investigate resonant and nonresonant contributions of the strength, which individually produce specific structures in the distributions. In addition, we propose a method to obtain the real-value strength using the complex values of spectroscopic factors of Gamow states. As a result, the 6He(2+) resonance is found to give the largest contribution.Comment: 11 pages, 10 figures, Corrected typo

Crossover from negative to positive shear rate dependence in granular friction

We conduct an experiment on the frictional properties of granular matter over a wide range of shear rate that covers both the quasistatic and the inertial regimes. We show that the friction coefficient exhibits negative shear-rate dependence in the quasistatic regime, whereas the shear-rate dependence is positive in the inertial regime. This crossover from negative to positive shear-rate dependence occurs at a critical inertial number. This is explained in terms of the competition between two physical processes, namely frictional healing and anelasticity. We also find that the result does not depend on the shape of the grains and that the behavior in the inertial regime is quantitatively the same as that in numerical simulations.Comment: 4 page

Reconciling aging and slip state evolutions from laboratory-derived canons of rate-and-state friction

The aging law and the slip law are two representative evolution laws of the rate- and state-dependent friction (RSF) law, based on canonical behaviors in three types of laboratory experiments: slide-hold-slide (SHS), velocity-step (VS), and steady-state (SS) tests. The aging law explains the SHS canon but contradicts the VS canon, and vice versa for the slip law. The later proposed composite law, which switches these two laws according to the slip rate $V$, explains both canons but contradicts the SS canon. The present study constructs evolution laws satisfying all three canons throughout the range of variables where experiments have confirmed the canons. By recompiling the three canons, we have derived constraints on the evolution law and find that the evolution rates in the strengthening phases of the SHS and VS canons are so different that complete reconciliation throughout the entire range of variables is mathematically impossible. However, for the limited range of variables probed by experiments so far, we have found that the SHS and VS canons can be reconciled without violating the SS canon by switching the evolution function according to $\Omega$, the ratio of the state $\theta$ to its steady-state value $\theta_{\rm SS}$ for the instantaneous slip rate. We could generally show that, as long as the state evolution rate $\dot \theta$ depends only on the instantaneous values of $V$ and $\theta$, simultaneous reproduction of the three canons, throughout the experimentally confirmed range, requires the aging-law-like evolution for $\Omega$ sufficiently below a threshold $\beta$ and the slip-law-like evolution for $\Omega$ sufficiently above $\beta$. The validity of the canons in existing experiments suggests $\beta \lesssim 0.01$.Comment: 90pages, 13 figure

The mechanics of first order splay faulting: The strike-slip case

First order splay faults, as defined here, are secondary faults that form at acute angles symmetrically on either side of a primary fault of the same sense of shear. We show that these faults form when the primary fault becomes critically misaligned with the principal stresses such that splay fault formation, on the optimum plane for faulting, is favored. First order splay faults, in distinction from other splay faults, are secondary only in the temporal sense – they are subsequent but not subordinate, in a tectonic sense, to the primary fault. Here we analyze the case of strike-slip faults, and compare it with data for several continental transform fault systems, where we show that the splay faults form in the most favorable direction: parallel to the plate motion vector. We also discuss and speculate on several outstanding problems with regard to first order splay faults: the placement of them in space, means by which primary faults become misoriented in the stress field, and the mechanics of first order splay fault-primary fault junctions, once formed

Editorial introduction: Transportation-oriented Urban Planning and Management

“2018 International workshop on urban planning and management, Toyota Japan” was held on 25-26th May 2018. Though some parts of the workshop such as keynote and special speeches, and oral sessions, etc., attendees widely discussed methods and applications of transportation oriented urban planning for achieving sustainable development