Structure and crystallization behaviour of syndiotactic polystyrene/layered double hydroxide nanocomposites

Syndiotactic polystyrene (sPS) based polymer nanocomposites have been prepared using surfactant‐free layered double hydroxides (SF‐LDHs) by a modified solvent mixing method with different loadings of 1, 2.5, 5 and 10 wt%. The nanocomposite preparation process involves a wash treatment of as‐prepared SF‐LDHs in an appropriate organic solvent followed by gel formation in a non‐polar solvent. The gel was directly used to make highly dispersed polymer nanocomposites. The influence of highly dispersed SF‐LDH platelets on the crystallization, polymorphism, thermal stability and flame retardancy of sPS was examined. It was shown that SF‐LDHs significantly enhance the crystallization rate of sPS and favour the formation of the thermodynamically stable β form along with the α form of sPS. Moreover, highly dispersed SF‐LDHs decrease the heat release rate and total heat release of sPS indicating the enhancement of flame‐retardant properties of sPS. In this way, it was found that the dispersed SF‐LDH platelets act as a multifunctional nanofiller for sPS. © 2015 Society of Chemical Industry     

Use of essential oil from Mentha arvensis L. to control storage moulds and insects in stored chickpea

BACKGROUND: Fungal contamination and Callosobruchus infestation results in qualitative and quantitative losses of chickpea seeds during storage. Most of the synthetic chemicals used as preservatives have adverse effects. Therefore, the antifungal and insecticidal potential of Mentha arvensis essential oil was evaluated to determine whether this could be an eco‐friendly substitute of synthetic preservatives. RESULTS: The stored chickpea seeds were dominated by Aspergillus flavus (46.1%) and 30% isolates among them were found toxigenic. The MIC of Mentha oil against A. flavus was recorded at 400 µL L^?1 and it exhibited broad fungitoxic activity against 14 storage fungi. The oil was found superior to some prevalent synthetic fungicides. Mentha oil showed potent insecticidal activity against Callosobruchus chinensis at different concentrations and exposure times. The oviposition by C. chinensis was completely checked at 10 µL L^?1 while F₁ emergence was completely inhibited at 200 µL L^?1. During in situ experiments, 94.05% protection of the chickpea from C. chinensis by Mentha oil showed superiority over the organophosphate insecticide malathion, where 90.75% protection was recorded. CONCLUSION: The Mentha EO showing potent fungitoxic and insecticidal efficacy and may be recommended as a plant‐based preservative in the management of fungal and insect infestation of chickpea and other pulses during storage. Copyright © 2009 Society of Chemical Industry     

Character of superposed states under deterministic LOCC

In this paper we investigate the effect of superposition of states on local conversion of pure bipartite states under deterministic LOCC. We are able to form a bridge between comparable and incomparable classes of states through the linear superposition of states. For example, if we consider two pairs of incomparable states, then their superposition may result into a comparable pair of states. We investigate many such cases and provide some of the results in tabular form. We also investigate the entanglement behavior of such classes of states, specifically their monotone nature. Finally we provide some bounds of different measures of entanglement based on the idea of comparability and incomparability under deterministic LOCC.     

Analysis of Climate and Melt-runoff in Dunagiri Glacier of Garhwal Himalaya (India)

The hydrology of high altitude glacierized basin in Himalaya is complex to understand due to high variability in climate and lack of hydro-meteorological data. In this study, analysis of hydrological, glacier ablation and meteorological records have been made for Dunagiri Glacier (~4,200 m) during the melt season (July - September), for the years 1985 and 1987–1989. In the daily cycle of mean diurnal discharge in summer months during 1985–1989, maximum discharge occurred at midnight, and minimum discharge occurred in the morning. Mean daytime and nighttime discharge volume was contributing approximately equal amounts. Such type of analysis will be the basis for designing/developing Run-off-the river type hydroelectric power projects which are heavily dependent on snow and glacier melt in Himalaya. Time series analysis of available hydro-meteorological records have been used to understand governing hydrological processes within the basin and to develop regression model for future development in runoff forecasting using climate data.     

Influence of nitrogen doping on the sputter-deposited WO3 films

Tungsten oxide films were produced using reactive rf magnetron sputtering. In this work, nitrogen doping was used to modify structural and, optical properties of the material in the presence of two inert gases (argon and helium). Substituting helium gas with argon results in a decrease in the particle sizes and thus affects the band gap values. Bandgap values were obtained over the range of 2.43 to 3.01 eV via incorporating oxygen-nitrogen-argon/helium mixtures in the gas ambient. It was also observed that the atomic mass of the sputtering gas plays a major role for changing the primary crystallite size as well as the surface morphology and texture.     

View factor calculation in the 2-D geometries using the collapsed dimension method

Usage of the collapsed dimension method (CDM) applied so far in solving radiative transport problems with participating media has been extended for the determination of view factors of the 2-D geometries. Unlike its application in the participating media, in view factor calculations, the CDM does not require tracing of rays, and thus its expressions are exact. To test the applicability of the CDM for the calculation of view factors, two geometries were considered. The CDM results were found to match precisely with the exact results. If in the CDM, the view factor expressions are not considered exact, the ray tracing becomes mandatory and, in this method too like the discrete ordinate method, the discrete transfer method and the finite volume method, ray effect manifests. For this situation, for a given number of control surfaces, effects of number rays were studied and trends were found similar to those found in other methods.     

Synthesis and corrosion protection study of poly(o-ethylaniline) coatings on copper

Poly(o-ethylaniline) coatings were synthesized on copper (Cu) by electrochemical polymerization of o-ethylaniline in an aqueous salicylate solution by using cyclic voltammetry. The characterization of these coatings was carried out by cyclic voltammetry, UV-visible absorption spectroscopy, Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The results of these characterizations indicate that the aqueous salicylate solution is a suitable medium for the electrochemical polymerization of o-ethylaniline to generate strongly adherent and smooth poly(o-ethylaniline) coatings on Cu substrates. The performance of poly(o-ethylaniline) as protective coating against corrosion of Cu in aqueous 3% NaCl was assessed by the potentiodynamic polarization technique and electrochemical impedance spectroscopy (EIS). The results of these studies demonstrate that the poly(o-ethylaniline) coating has ability to protect the Cu against corrosion. The corrosion potential was about 0.078 V versus SCE more positive in aqueous 3% NaCl for the poly(o-ethylaniline) coated Cu (∼ 15 μm thick) than that of uncoated Cu and reduces the corrosion rate of Cu almost by a factor of 70.