Spin polarization amplification within nonmagnetic semiconductors at room temperature

We demonstrate theoretically that the spin polarization of current can be electrically amplified within nonmagnetic semiconductors by exploiting the fact the spin current, compared to the charge current, is weakly perturbed by electric driving forces. As a specific example, we consider a T-shaped current branching geometry made entirely of a nonmagnetic semiconductor, where the current is injected into one of the branches (input branch) and splits into the other two branches (output branches). We show that when the input current has a moderate spin polarization, the spin polarization in one of the output branches can be higher than the spin polarization in the input branch and may reach 100% when the relative magnitudes of current-driving electric fields in the two output branches are properly tuned. The proposed amplification scheme does not use ferromagnets or magnetic fields, and does not require low temperature operation, providing an efficient way to generate a highly spin polarized current in nonmagnetic semiconductors at room temperature.Comment: 11 pages, 2 figures, to appear in Phys. Rev.

Current-induced domain wall motion in a nanowire with perpendicular magnetic anisotropy

We study theoretically the current-induced magnetic domain wall motion in a metallic nanowire with perpendicular magnetic anisotropy. The anisotropy can reduce the critical current density of the domain wall motion. We explain the reduction mechanism and identify the maximal reduction conditions. This result facilitates both fundamental studies and device applications of the current- induced domain wall motion

Current-Induced Magnetic Domain-Wall Motion by Spin Transfer Torque: Collective Coordinate Approach with Domain-Wall Width Variation

The spin transfer torque generated by a spin-polarized current can induce the shift of the magnetic domain-wall position. In this work, we study theoretically the current-induced domain-wall motion by using the collective coordinate approach [Gen Tatara and Hiroshi Kohno, Phys. Rev. Lett. 92, 86601 (2004)]. The approach is extended to include not only the domain-wall position and the polarization angle changes but also the domain-wall width variation. It is demonstrated that the width variation affects the critical current.Comment: 13 pages, 3 figure

DECAY FACTOR WITH EXPERIMENTAL VARIABLES IN TWO CIRCULATING FLUIDIZED BED (CFB) RISERS

The effects of the riser inlet velocity, solid mass flux and particle size on the axial solid holdup profile and decay factor were investigated using two circulating fluidized beds (CFBs) with FCC (Geldart A) particles as the bed materials. Based on the experimental results from the two-CFBs, the axial solid holdup in the two CFBs were compared with the correlations of previous studies. Also, an empirical correlation was proposed for decay factor that exhibited a good agreement with experimental data

Quantifying the environmental burdens of the hot mix asphalt (HMA) pavements and the production of warm mix asphalt (WMA)

AbstractAsphalt pavement has significant environmental burdens throughout its life cycle. A life cycle assessment (LCA) model is used to quantify the environmental burdens for material, construction, maintenance and use phases of hot mix asphalt (HMA) pavement. Two peer reviewed journals have been used to collect all of the inventory loadings as an input for the LCA model and ten impact categories have been evaluated as output. The result of the inventory analysis is a summary of all inflows and outflows related to the “functional unit”. The result of each impact category is the total of all the individually characterized inventory loadings in each category. Each life cycle phase of HMA pavement has been quantified on these ten impact categories and a comparison provided among the phases to understand the percentage contribution to the environment. Human and eco toxicity values are higher for the material phase, whereas the rest of the impact categories are significant in the use phase. The material phase contributes 97% of the overall human toxicity in water from standpoint of asphalt pavements, whereas in the material phase the production of bitumen is responsible for 90% human and eco toxicity in terms of air based burden. As a solution, the life cycle inventory of WMA has been estimated and reduction only done in HMA production. From analysis, it was estimated that WMA provides a reduction of 29% on the acidification impact and 25% reduction on both fossil fuel consumption and photo oxidant formation impact of HMA

A STUDY OF MOTION CHARACTERISTICS LED BY CONNECTION METHODS AND POSITIONS OF A WAVE-ENERGY CONVERTER IN A REGULAR WAVE

The potential of wave power as an alternative energy resource is being studied to address problems associated with fossil fuel exhaustion and environmental pollution. In this paper, to improve the power generation efficiency of a floating-type wave-energy converter that has an activating body, the effects of the positions of a connecting bridge and different connecting methods between a main body and the activating body of the wave-energy converter were studied. In order to research the activating body’s motion characteristics that are caused by the changes of connecting bridge’s position and connecting methods; hinged or fixed connector, the wave-energy converter was modeled and simulated by using a commercial software. The moment and angular velocity of the axis of power generation were measured from the results of simulations and then the power outputs were calculated based on the moment and angular velocity. The outputs, which were analyzed under several regular wave conditions, were compared to each other

Exploring a Process Model for Stakeholder Management

This paper expands stakeholder management practice by incorporating concepts from the issues management process model. Based on Jones and Chase’s issuesprocess model, this study provides a comprehensive three-step stakeholder management process: (1) stakeholder identification and analysis, (2) development and implementation of stakeholder management strategies, and (3) stakeholder management evaluation. From a practical point of view, the stakeholder identification step helps organizations picture what types of reactions or attacks will occur in the near future. In addition, stakeholder analysis allows organizations to enlist salient stakeholders and offers a practical initiation into stakeholder management. The criteria for stakeholder identification and analysis in this model can provide practical guidelines for ongoing brainstorming drills within organizations to determine which stakeholders should be engaged. Furthermore, an organization’s stakeholder management strategies are created and selected according to stakeholder categories on the basis of types and priorities. This cyclical process can motivate organizations to continue their implementation and evaluation, which will lead to an effective and efficient issues management process that can result in the construction of a better society

Glomerular Fingerprint Deposits In Hepatitis B Virus-associated Nephropathy

Fingerprint deposits have been considered as a characteristic feature of lupus nephritis. We report such deposits in a case with hepatitis B virus-associated membranoproliferative glomerulonephritis. The patient did not show any sign of systemic lupus erythematosus at time of biopsy or during a 3· year follow-up period