Design and analysis of RF MEMS shunt switch for V-band applications

Microsystem Technologies - In this paper, we have designed and simulations of RF MEMS shunt switch. The electro-mechanical and electromagnetic analysis of the switch have been done using COMSOL...     

Isolation and purification of a novel antioxidant protein from the water extract of Sundakai (Solanum torvum) seeds

Reactive oxygen species (ROS) at physiological concentrations may be required for normal cell function. Excessive production of ROS can be detrimental to cells, because ROS can cause oxidative damage to lipids, proteins, and DNA. Herein, we describe the isolation and purification of a novel antioxidant protein the water extract of dried, powdered Sundakai (Solanum torvum [Solanaceae]) seeds. Sundakai belongs to the Solanaceae family, a small shrub, which is distributed widely in India, Malaya, China, Phillipines and tropical America. Fifty percent of ammonium sulphate-precipitated crude water extract was fractionated on a Sephadex G100 column, which yielded two peaks, PI and PII. Peaks PI and PII inhibited lipid peroxidation up to 40% and 89%, respectively in linolenic acid micelles. Rechromatographing of peak PII on Sephadex G100 yielded a single peak, indicating the homogeneity of the purified protein. SDS–PAGE analysis indicated the molecular weight of the purified protein to be ∼28 kDa. The purified protein, at 0.8 μM, inhibited deoxyribose degradation induced by generation of hydroxyl radicals by 90% and scavenged DPPH (1,1-diphenyl-2-picrylhydrazyl) radicals by 76%. The reducing power and chelating power of the purified protein, at 0.8 μM, were found to be 72% and 85%, respectively. The protein, at 0.8 μM, also offered significant protection to calf thymus DNA damage induced by H₂O₂ (1 mM). Therefore, the present study demonstrates, for the first time, a novel protein from the water extract of Sundakai seeds as an excellent antioxidant.     

Static and dynamic characteristics of short wavy journal bearings

A general analysis has been done to investigate the static and dynamic performance of short wavy journal bearing. Reynolds equation is solved for both steady‐ and unsteady‐state operations. The steady‐state analysis has been done and compared with circular bearing with respect to their load capacity, flow rate, pressure distribution and friction factor. The unsteady‐state analysis has been used to determine the rotor dynamic coefficients for various eccentricity ratios. These coefficients are used to determine the stability parameters, such as critical mass and whirl ratio, and prove that wave bearing has not only better load carrying capacity but also provides better stability at high speed than circular bearing. Copyright © 2010 John Wiley & Sons, Ltd.     

Polyindole-Au nanocomposite produced at the liquid/liquid interface

This letter is a continuation of our previous work on synthesis of polyindole-gold nanocomposite published in this journal. In the present work, we have synthesized the similar hybrid organo-inorganic composite using a novel interfacial polymerization route at water/dichloromethane interface. The hybrid organo-inorganic composite material is based on conducting polymer, polyindole and gold nanoparticles; the redox character of indole (monomer) and chloroauric acid facilitates the polymerization of monomer. Entirely different morphological and structural features are observed compared to our previous results. The contact of monomer and metal salt acid (chloroauric acid) at the interface results in the formation of polyindole-Au nanocomposite (without any need of template or capping agent) of nanorod morphology encapsulating Au nanoparticles. XRD studies shows semi-crystalline nature of the polymer unlike the amorphous polyindole formed using other methods. Tunable photoluminescence spectra show the potential applications of the composite in the field of organic laser and organic optoelectronics.     

Hybrid Nanostructures for Energy Storage Applications

Materials engineering plays a key role in the field of energy storage. In particular, engineering materials at the nanoscale offers unique properties resulting in high performance electrodes and electrolytes in various energy storage devices. Consequently, considerable efforts have been made in recent years to fulfill the future requirements of electrochemical energy storage using these advanced materials. Various multi‐functional hybrid nanostructured materials are currently being studied to improve energy and power densities of next generation storage devices. This review describes some of the recent progress in the synthesis of different types of hybrid nanostructures using template assisted and non‐template based methods. The potential applications and recent research efforts to utilize these hybrid nanostructures to enhance the electrochemical energy storage properties of Li‐ion battery and supercapacitor are discussed. This review also briefly outlines some of the recent progress and new approaches being explored in the techniques of fabrication of 3D battery structures using hybrid nanoarchitectures.     

Synthesis and hydrogen storage properties of different types of boron nitride nanostructures

The present work reports the synthesis and hydrogen storage properties of different types of boron nitride (BN) nanostructures prepared by an in situ silica-assisted catalytic chemical vapor deposition technique. The BN nanostructures have been characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), Brunauer, Emmett, and Teller (BET), Raman spectroscopy and Fourier transform infrared (FTIR) spectroscopy studies. The hydrogen storage properties of BN nanostructures have been investigated using a high-pressure Seiverts' apparatus in the pressure range of 1–100 bar and at 298 K. The dependence of hydrogen storage capacity on the morphology of BN nanostructures is discussed in detail.