Superior Supercapacitors based on Biowaste Materials

Carbon nano spheres derived from Allium cepa were synthesized at different temperatures in a one-step pyrolysis process for supercapacitor electrodes. Obtained carbon nano spheres were analyzed using SEM, FTIR, BET and XRD. The nano materials were fabricated into conducting electrodes for cyclic voltammetry, constant current charge-discharge and electrochemical impedance spectroscopy studies. All the studies were done in 3.0 M KOH electrolyte. Specific capacitance from charge discharge experiments were found to be 132.03 F/g and 149.49 F/g for nano materials synthesized at 500ºC and 600ºC respectively. Obtained values suggest a way forward in producing a green electrode for commercial applications

Enhancement of magnetoresistance in manganite multilayers

Magnanite multilayers have been fabricated using La0.67Ca0.33MnO3 as the ferromagnetic layer and Pr0.7Ca0.3MnO3 and Nd0.5Ca0.5MnO3 as the spacer layers. All the multilayers were grown on LaAlO3 (100) by pulse laser deposition. An enhanced magnetoresistnace (defined (RH- R0)/R0) of more than 98% is observed in these multilayers. Also a low field magnetoresistance of 41% at 5000 Oe is observed in these multilayer films. The enhanced MR is attributed to the induced double exchange in the spacer layer, which is giving rise to more number of conducting carriers. This is compared by replacing the spacer layer with LaMnO3 where Mn exists only in 3+ state and no enhancement is observed in the La0.67Ca0.33MnO3 / LaMnO3 multilayers as double exchange mechanism can not be induced by external magnetic fields.Comment: 13 pages, 5 Figure

Night sky at the Indian Astronomical Observatory during 2000-2008

We present an analysis of the optical night sky brightness and extinction coefficient measurements in UBVRI at the Indian Astronomical Observatory (IAO), Hanle, during the period 2003-2008. They are obtained from an analysis of CCD images acquired at the 2 m Himalayan Chandra Telescope at IAO. Night sky brightness was estimated using 210 HFOSC images obtained on 47 nights and covering the declining phase of solar activity cycle-23. The zenith corrected values of the moonless night sky brightness in mag/square arcsecs are 22.14(U), 22.42(B), 21.28(V), 20.54(R) and 18.86(I) band. This shows that IAO is a dark site for optical observations. No clear dependency of sky brightness with solar activity is found. Extinction values at IAO are derived from an analysis of 1325 images over 58 nights. They are found to be 0.36 in U-band, 0.21 in B-band, 0.12 in V-band, 0.09 in R-band and 0.05 in I-band. On average, extinction during the summer months is slightly larger than that during the winter months. No clear evidence for a correlation between extinction in all bands and the average night time wind speed is found. Also presented here is the low resolution moonless optical night sky spectrum for IAO covering the wavelength range 3000-9300 \AA. Hanle region thus has the required characteristics of a good astronomical site in terms of night sky brightness and extinction, and could be a natural candidate site for any future large aperture Indian optical-infrared telescope(s).Comment: 18 pages, 7 figures, uses basi.cls, accepted for publication in Bulletin of the Astronomical Society of Indi

Ayurvedic management of Diabetic Foot Ulcer - A Case Study

There are 424.9 million adults estimated to currently have diabetes globally.[1] Diabetic patients have an inherent risk of foot problems. Globally every 30 seconds, a major amputation occurs; 85% of which are preceded by trivial foot lesions.[2] In Ayurvedic literature, it is explained that Pidakas are formed in Adhoshaka in patients with Prameha due to the weakness of Rasayanis of lower limbs.[3] Such Pidakas if neglected over a period of time, without treatment will undergo Paaka and form a Vrana. Acharya Sushruta has described Shashti Upakramas (60 modalities) for the successful management of Vranas. Among them this article highlights the use of Shodhana, Kshara Varma, Chedana, Ropana and Bandhana Upakramas in the management of Diabetic Foot Ulcer/ Madhumehajanya Dushtavrana and also the need of Shastrakarma (surgical intervention) at the right time. In this study, Triphala Kashaya Avagaha and Pratisaraneeya kshara Karma for Vranashodhana, Chedana Karma followed by Ropana with Jatyaditaila was carried out. The course of treatment carried out brought about Dushtavranaavastha to Shuddhavranaavastha

The Zero-n Gap Soliton

Periodic structures consisting of alternating layers of positive index and negative index materials possess a novel band gap at the frequency at which the average refractive index is zero. We show that in the presence of a Kerr nonlinearity, this zero-n gap can switch from low transmission to a perfectly transmitting state, forming a nonlinear resonance or gap soliton in the process. This zero-n gap soliton is omnidirectional in contrast to the usual Bragg gap soliton of positive index periodic structure

Seed abortion in Pongamia pinnata (Fabaceae)

In Pongamia pinnata only one of the two ovules develops into a seed in most of the pods. Since pollen was not found to be limiting and reduced fertilization could not completely explain the observed frequency of seed abortion, it implied an effect of postfertilization factors. Aqueous extracts of developing seeds and maternal tissue (placenta) did not influence abortion in vitro, suggesting that abortion may not be mediated by a chemical. Experimental uptake of 14C sucrose in vitro indicated that both the stigmatic and the peduncular seed have similar inherent capacities of drawing resources, but the peduncular seed is deprived of resources in the presence of the stigmatic seed. This deprivation of the peduncular seed could be offset by supplying an excess of hormones leading to the subsequent formation of two seeds in a pod. The prevalence of single-seeded pods in P. pinnata seems therefore to be a result of competition between the two seeds for maternal resources. The evolutionary significance of single-seeded pods in P. pinnata is discussed with respect to possible dispersal advantage enjoyed by such pods