Rock Joint Surfaces Measurement and Analysis of Aperture Distribution under Different Normal and Shear Loading Using GIS

Geometry of the rock joint is a governing factor for joint mechanical and hydraulic behavior. A new method of evaluating aperture distribution based on measurement of joint surfaces and three dimensional characteristics of each surface is developed. Artificial joint of granite surfaces are measured,processed, analyzed and three dimensional approaches are carried out for surface characterization. Parameters such as asperity's heights, slope angles, and aspects distribution at micro scale,local concentration of elements and their spatial localization at local scale are determined by Geographic Information System (GIS). Changes of aperture distribution at different normal stresses and various shear displacements are visualized and interpreted. Increasing normal load causes negative changes in aperture frequency distribution which indicates high joint matching. However, increasing shear displacement causes a rapid increase in the aperture and positive changes in the aperture frequency distribution which could be due to unmatching, surface anisotropy and spatial localization of contact points with proceeding shear

Critical current destabilizing perpendicular magnetization by the spin Hall effect

The critical current needed to destabilize the magnetization of a perpendicular ferromagnet via the spin Hall effect is studied. Both the dampinglike and fieldlike torques associated with the spin current generated by the spin Hall effect is included in the Landau-Lifshitz-Gilbert equation to model the system. In the absence of the fieldlike torque, the critical current is independent of the damping constant and is much larger than that of conventional spin torque switching of collinear magnetic systems, as in magnetic tunnel junctions. With the fieldlike torque included, we find that the critical current scales with the damping constant as $\alpha^{0}$ (i.e., damping independent),$\alpha$, and $\alpha^{1/2}$ depending on the sign of the fieldlike torque and other parameters such as the external field. Numerical and analytical results show that the critical current can be significantly reduced when the fieldlike torque possesses the appropriate sign, i.e. when the effective field associated with the fieldlike torque is pointing opposite to the spin direction of the incoming electrons. These results provide a pathway to reducing the current needed to switch magnetization using the spin Hall effect.Comment: 12 pages, 8 figure

Current-Induced Instability of a Perpendicular Ferromagnet in Spin Hall Geometry

We develop a theoretical formula of spin Hall torque in the presence of two ferromagnets. While the direction of the conventional spin Hall torque always points to the in-plane direction, the present system enables to manipulate the torque direction acting on one magnetization by changing the direction of another magnetization. Based on the diffusion equation of the spin accumulation and the Landauer formula, we derive analytical formula of the spin Hall torque. The present model provides a solution to switch a perpendicular ferromagnet deterministically at zero field using the spin Hall effect.Comment: 5 pages, 2 figures, conference proceeding of Joing MMM/Intermag conference 201

Does gender matter for demand revelation in threshold public goods experiments?

We examine the effect of gender on real and hypothetical contributions in a threshold public goods experiment using heterogeneous induced-values approach. Our analysis of the experimental data leads to several findings. First, gender differences in contributions are found for hypothetical payments, but not for real payments. This result is obtained while controlling for subjects' true values (induced-values) as well as socio-economic variables. Second, females are more likely to truthfully reveal their true value than males for hypothetical payments, but this effect is not significant for real payments. One could interpret these results as suggesting that females are more likely to state their value through hypothetical payments.Contingent valuation

Microwave assisted resonant domain wall nucleation in permalloy nanowires

We have designed a system to study microwave assisted domain wall nucleation in permalloy nanowires. We find a substantial decrease in the nucleation field when microwave fields are applied, in comparison to pulse fields. A clear resonance peak is observed in the frequency dependence of the nucleation field, which coincides with the uniform mode ferromagnetic resonance frequency. Owing to the well-defined nucleation process, the switching field distribution is small in contrast to previous reports. Our results show that localized microwave field provides an efficient tool for injecting domain walls into magnetic nanowires

Spectral Energy Distribution of the First Galaxies: Contribution from Pre-Main-Sequence Stars

One of the major goals of next-generation space-borne and ground-based telescopes is to detect and characterize the first galaxies that were in place in the first few hundred million years after the big bang. We study the spectral energy distribution (SED) of the first galaxies and discuss the prospects for detection and identification. We consider very young star-forming galaxies at $z=15$ and incorporate the contribution from pre-main-sequence (PMS) stars. Unlike in the present-day galaxies, primordial protostars are not embedded in dusty gas clouds, and hence the light from them can be visible at a wide range of wavelengths. We use MESA code to follow the PMS evolution and use the BT-Settl model to calculate the SED of individual PMS stars. We show that PMS stars contribute to boost the flux in the mid-infrared, and that the galaxy SED at very early evolutionary phases is overall redder than at later phases. The infrared flux contribution is comparable to that caused by emission lines powered by massive stars. We argue that the contribution from PMS stars is important for characterizing young galaxies in the early Universe and also for target selection with future deep galaxy surveys.Comment: 5 pages, 4 figures, published online in MNRAS letter

Spin Hall magnetoresistance in metallic bilayers

Spin Hall magnetoresistance (SMR) is studied in metallic bilayers that consist of heavy metal (HM) layer and a ferromagnetic metal (FM) layer. We find nearly a ten-fold increase of SMR in W/CoFeB compared to previously studied HM/ferromagnetic insulator (FI) systems. The SMR increases with decreasing temperature despite the negligible change in the W layer resistivity with temperature. A model is developed to account for the absorption of the longitudinal spin current to the FM layer, one of the key characteristics of a metallic ferromagnet. We find that the model not only quantitatively describes the HM layer thickness dependence of SMR, allowing accurate estimation of the spin Hall angle and the spin diffusion length of the HM layer, but also can account for the temperature dependence of SMR by assuming a temperature dependent spin polarization of the FM layer. These results illustrate the unique role a metallic ferromagnetic layer plays in defining spin transmission across the HM/FM interface

Providing quality recreation experiences in Japan

This paper uses a choice experiment to evaluate the benefits to trekkers of the natural environment and the provision of appropriate recreation experiences in the Uryu-numa Mire, northern Japan. The result, applying a conditional logit model, shows that restoration of the natural environment are positively valued by trekkers, and their respective willingness to pay for one percentage point improvement are JPY 32.6 and 59.6. Likewise, provision of appropriate recreation experiences, setting a limit on the number of trekkers a day, is also positively valued. The results indicate that the optimal number of trekkers is 458, and the willingness to pay for controlling the number of trekkers from 800 to 458 is JPY 1,457. In Japan, importance of the quality of recreation experiences is not well recognized by park managers. However, our results indicate that both restoring the environment and providing excellent recreation experiences are significant challenges for recreation areas.

Effective treatment of a steroid-induced femoral neck fracture nonunion with a once-weekly administration of teriparatide in a rheumatoid patient: a case report

INTRODUCTION: Nonunion of femoral neck fractures frequently occurs in elderly patients. In patients with rheumatoid arthritis, reoperation rates after internal fixation of a displaced femoral neck fracture increase by up to 60 %. Revision surgery with arthroplasty is often preferred for nonunion of femoral neck fractures because there are few effective options for conservative treatment. Teriparatide (TPTD) is a human parathyroid hormone analog and the only anabolic drug for the treatment of severe osteoporosis. DISCUSSION: There are two types of treatment regimens using TPTD: a once-daily administration of recombinant type TPTD and a once-weekly administration of a chemically synthesized type. Although there have been some reports showing that the once-daily recombinant type TPTD was effective for nonunion treatment, the effect of a once-weekly administration of the chemically synthesized type of TPTD is unknown. This report shows the efficacy of the chemically synthesized TPTD for the treatment of femoral neck fracture nonunion in a patient with risk factors that include rheumatoid arthritis and steroid intake

Self-Organization of Vortex Length Distribution in Quantum Turbulence: An Approach from the Barabasi-Albert Model

The energy spectrum of quantum turbulence obeys Kolmogorov's law. The vortex length distribution (VLD), meaning the size distribution of the vortices, in Kolmogorov quantum turbulence also obeys a power law. We propose here an innovative idea to study the origin of the power law of the VLD. The nature of quantized vortices allows one to describe the decay of quantum turbulence with a simple model that is similar to the Barabasi-Albert model of large networks. We show here that such a model can reproduce the power law of the VLD well.Comment: 4 pages including 5 figure