Controlled engineering of spin polarized transport properties in a zigzag graphene nanojunction

We investigate a novel way to manipulate the spin polarized transmission in a two terminal zigzag graphene nanoribbon in presence of Rashba spin-orbit (SO) interaction with circular shaped cavity engraved into it. A usual technique to control the spin polarized transport behaviour of a nanoribbon can be achieved by tuning the strength of the SO coupling, while we show that an efficient engineering of the spin polarized transport properties can also be done via cavities of different radii engraved in the nanoribbon. Simplicity of the technique in creating such cavities in the experiments renders an additional handle to explore transport properties as a function of the location of the cavity in the nanoribbon. Further, a systematic assessment of the interplay of the Rashba interaction and the dimensions of the nanoribbon is presented. These results should provide useful input to the spintronic behaviour of such devices. In addition to the spin polarization, we have also included an interesting discussion on the charge transmission properties of the nanoribbon, where, in absence of any SO interaction a metal-insulator transition induced by the presence of a cavity is observed.Comment: 7 pages, 9 figures (Accepted in Europhysics Letters

Chirality Reversing Active Brownian Motion in Two Dimensions

We study the dynamics of a chirality reversing active Brownian particle, which models the chirality reversing active motion common in many microorganisms and microswimmers. We show that, for such a motion, the presence of the two time-scales set by the chirality reversing rate $\gamma$ and rotational diffusion constant $D_R$ gives rise to four dynamical regimes, namely, (I) $t \ll \text{min}(\gamma^{-1}, D_R^{-1})$, (II) $\gamma^{-1} \ll t \ll D_R^{-1}$, (III) $D_R^{-1} \ll t \ll \gamma^{-1}$ and (IV) $t \gg \text{max}(\gamma^{-1}, D_R^{-1})$, each showing different behaviour. The short-time regime (I) is characterized by a strongly anisotropic and non-Gaussian position distribution, which crosses over to a diffusive Gaussian behaviour in the long-time regime (IV) via an intermediate regime (II) or (III), depending on the relative strength of $\gamma$ and $D_R$. In regime (II), the chirality reversing active Brownian motion reduces to that of an ordinary active Brownian particle, with an effective rotation diffusion coefficient which depends on the angular velocity. Finally, we find that, the regime (III) is characterized by an effective chiral active Brownian motion.Comment: 13 pages, 7 figure

Evaluation of impact of landscape changes on large Mammal Habitats in Pench Tiger Reserve, Madhya Pradesh, India

Not availabl

Effect of pre-treatment on physicochemical, microstructural and pasting properties of pearl millet and cowpea

The effects of soaking, germination and fermentation on physicochemical, microstructural and pasting properties of improved and drought-tolerant Mozambican varieties of pearl millet and cowpea were investigated. Total starch content in both germinated pearl millet (GPM, 67.2 % of DM) and germinated cowpea (GCP, 47.4 % of DM) was found to be affected by germination, which consequently affected the amylose content of GPM and GCP. Morphological and pasting properties of pearl millet starch granules were altered by germination, with numerous holes and broken starch granules developing, leading to a drastic reduction in final viscosity (4 mPa.s). Cowpea starch granule structure was not markedly affected by pre-treatment, but peak (310 mPa.s) and final viscosity (196 mPa.s) were decreased by germination. Cowpea flour had smaller particle size distribution than pearl millet, but no significant differences in the flour were observed after pre-treatment (soaking, germination, fermentation). Therefore, these simple, low-cost and culturally acceptable treatments can be used to alter technical functionality and improve the nutritional benefits of flour, e.g. different pre-treatments of pearl millet and cowpea could be used to develop food products with high energy density and acceptable sensory profile such as porridge for undernourished children in low and middle-income countries

Real time simulation of rail dispacher operations

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1999.Includes bibliographical references (leaf 120).by Santanu Basu.S.M