Texturing of high T(sub c) superconducting polycrystalline fibers/wires by laser-driven directional solidification in an thermal gradient

This paper summarizes the technique of laser-driven directional solidification in a controlled thermal gradient of yttria stabilized zirconia core coated Y-Ba-Cu-O materials to produce textured high T(sub c) superconducting polycrystalline fibers/wires with improved critical current densities in the extended range of magnetic fields at temperatures greater than 77 K. The approach involves laser heating to minimize phase segregation by heating very rapidly through the two-phase incongruent melt region to the single phase melt region and directionally solidifying in a controlled thermal gradient to achieve highly textured grains in the fiber axis direction. The technique offers a higher grain growth rate and a lower thermal budget compared with a conventional thermal gradient and is amenable as a continuous process for improving the J(sub c) of high T(sub c) superconducting polycrystalline fibers/wires. The technique has the advantage of suppressing weak-link behavior by orientation of crystals, formation of dense structures with enhanced connectivity, formation of fewer and cleaner grain boundaries, and minimization of phase segregation in the incongruent melt region

Effects of different doses of nitrogen treatments on isoprene emission from Ficus glomerata

In the present investigation on the effect of nitrogen treatments on emission of isoprene from Ficus glomerata has been evaluated. Four sets of plants were treated with following four doses of nitrogen in the form of ammonium nitrate solution (i) 10 mM (ii) 50 mM (iii) 100 mM (iv) 200 (mM) and control set was designed without any treatment. Nitrogen treated as well as control plants were sampled for isoprene emission using a dynamic flow through enclosure chamber technique and samples were analysed with the help of GC-FID. Isoprene emissions from control, 10 mM, 50 mM, 100 mM, and 200 mM nitrogen treated plants were found to be 27.5 ± 4 ?gg-1h-1, 56 ± 6 ?gg-1h-1, 91 ± 11 ?gg-1h-1, 101 ± 10 ?gg-1h-1, and 15 ± 4 ?gg-1h-1 respectively. Lowest isoprene emission (15 ± 4 ?gg-1h-1) was noticed in plants treated with 200 mM nitrogen. Isoprene emissions were found to increase exponentially in plants treated with nitrogen up to 100 mM. Nevertheless, plants treated with 200 mM nitrogen exhibited decrease in emission by 46 per cent, probably on account of nitrite toxicity and reduction in soil pH at high nitrogen dose