Study of Thermally Activated Phase-Slip and Scaling of Magneto-Resistance Near TC in YBa2Cu3O7−δ/Ag bulk composites

Journal of Superconductivity and Novel Magnetism - Dissipation in YBCO polycrystalline bulk samples added with nominally different amounts of silver (0, 5, 15, 25 wt%) has been studied through...     

Electrical behaviour of discontinuous silver films deposited on softened polystyrene and poly (4-vinylpyridine) blends

Results of the studies carried out on the electrical behaviour of silver island films deposited on the blends of polystyrene (PS) and poly (4-vinylpyridine) (P4VP) are presented here. The substrates were held at 457 K, much above the glass transition temperature of both the polymers to ensure sufficient polymer fluidity during deposition, to obtain a sub-surface particulate film. A constant deposition rate of 0.4 nm/s was used throughout the study. Films on softened PS gives rise to a very high room temperature resistance approaching that of the substrate resistance due to the formation of a highly agglomerated structure. On the other hand, films on softened P4VP gives rise to a room temperature resistance in the range of a few tens to a few hundred MΩ/, which is desirable for device applications. The blends of PS and P4VP show room temperature resistances in the desirable range even at a PS/P4VP ratio of 75:25. The films show an increase in resistance when they are exposed to atmosphere. This is attributed to the oxidation of silver islands. The film resistances in the desired range could be obtained even after exposure to atmosphere up to a PS concentration of 50%.     

Changes in the glaciers of Chandra–Bhaga basin,Himachal Himalaya,India, between 1980 and 2010 measured using remote sensing

This study reports the glacier changes of Chandra–Bhaga basin, northwest Himalaya, India, from 1980 to 2010. Satellite remote-sensing data from the Landsat Multispectral Scanner (MSS) and Thematic Mapper (TM), the Linear Imaging Self Scanning Sensor (LISS) and Advanced Wide Field Sensor (AWiFS) of the Indian Remote Sensing (IRS) series, and the Shuttle Radar Topography Mission (SRTM) digital elevation model (DEM) were used to study the changes in glacier parameters such as glacier area, length, snout elevation, and the impact of glacier topographical parameters (glacier slope, aspect, and altitude range) on the glacier changes. It was found that the total glaciated area had shrunk to 368.2 km² in 2010 from 377.6 km² in 1980, a loss of 2.5%. The average position of glacier terminuses retreated by 465.5 ± 169.1 m from 1980 to 2010 with an average rate of 15.5 ± 5.6 m year^?1. The decadal scale analysis showed that the average rate of retreat had increased the most in the recent decade. A moraine-dammed lake located in the study region was found to have expanded in area from (0.65 ± 0.01) km² in 1980 to (1.26 ± 0.03) km² in 2010. Glaciers with steep slope and less altitude range have lost more area than the glaciers having gentle slope and greater altitude range.     

Type, extent and use of colours in ready-to-eat (RTE) foods prepared in the non-industrial sector – a case study from Hyderabad, India

The type and extent of colours added to ready‐to‐eat (RTE) foods prepared in the non‐industrial sector of India was investigated. Of the 545 RTE foods analysed, 90% contained permitted colours, 2% contained a combination of permitted and non‐permitted colours and 8% contained only non‐permitted colours. However in RTE foods with permitted colours, 73% exceeded 100 ppm, as prescribed by the Prevention of Food Adulteration Act of India, and 27% were within the prescribed levels. Among the permitted colours, tartrazine was the most widely used colour followed by sunset yellow. The maximum concentration of colours was detected in sweet meats (18 767 ppm), non‐alcoholic beverages (9450 ppm), miscellaneous foods (6106 ppm) and hard‐boiled sugar confectioneries (3811 ppm). Among the non‐permitted colours found, rhodamine was most commonly used. Some of the foods, such as savouries and miscellaneous foods like sugar coated aniseed and almond milk, are not supposed to contain colours as per the Prevention of Food Adulteration Act, but were found to contain colours.     

An E-plane ferrite loaded simple waveguide radiator

Experimental investigations were conducted to examine the effect of dielectric loading on a ferrite loaded waveguide radiator (notch antenna). The antenna was made by symmetrically tapering an X-band waveguide. A cylindrical ferrite post was disposed at the apex of the notch and it was biased with a dc magnetic field. The antenna was tested for several notch angles namely 140/spl deg/, 120/spl deg/, 90/spl deg/, 80/spl deg/, 60/spl deg/ while ferrite was loaded with several dielectric sleeves, such as wood, polymer, pyrex. The dielectric loading with high permittivity material is found to give better radiation and scanning characteristics. The radial thickness of the dielectric ring is observed to affect the radiation.     

Transalkylation of toluene with C9 aromatic hydrocarbons over ZSM5 zeolites

The transalkylation reactions of a mixture of toluene and C₉⁺ aromatics were studied over HZSM5 catalysts of varying SiO₂:Al₂O₃ ratios (30–800) as well as over a NiHZSM5 catalyst. As the SiO₂: Al₂O₃ ratio is increased, the rate of transalkylation is decreased. Among the C₉ aromatics that were present in the feed, the ethyl toluenes were extensively de-ethylated to toluene. The shape-selective characteristics of the ZSM5 zeolite were revealed through the relative order of reactivity of the three trimethyl benzene isomers 1.2.4>1.2.3>1.3.5. The stable life of the catalyst can be prolonged by the incorporation of nickel. The influences of process parameters such as temperature, pressure, space velocity and H₂: hydrocarbon ratio are also presented. It was observed that the transalkylation of C₉ aromatics with toluene to yield xylenes occurs mainly on the external surface of the ZSM5 crystals. The disproportionation of toluene to yield benzene and xylene, however, takes place predominantly in the pore system.     

Provably secure lightweight client authentication scheme with anonymity for TMIS using chaotic hash function

The Journal of Supercomputing - Telecare medicine information system (TMIS) is recognized as an important tool for improving the quality and protection of healthcare services. In addition to...     

Structural properties of silver particulate films deposited on softened polymer blends of polystyrene/poly (2-vinyl pyridine)

Results of the structural studies of silver particulate films deposited at a rate of 0.4 nm/s on polymeric blends of polystyrene/poly (2-vinyl pyridine), PS/P2VP held at a temperature 457 K by evaporation in a vacuum of 8 × 10⁻⁶ Torr are reported here. The morphology of silver particulate films, characterized by their size, size distribution, shape and inter-particle separation, was observed to modify due to blending of PS with P2VP and amount of silver deposited. The red shift in the plasmon resonance indicates the effect of blending P2VP with PS. Scanning electron microscopy was used to study the change in morphology of the silver nanoparticles in correlation with the optical properties of silver particulate films on PS/P2VP blends. The silver nanoparticles on the thin layers of polymer blends exhibited much smaller, narrower dispersion and wide size distribution due to blending of PS with P2VP.