Plasma heating due to X-B mode conversion in a cylindrical ECR plasma system

Extra Ordinary (X) mode conversion to Bernstein wave near Upper Hybrid Resonance (UHR) layer plays an important role in plasma heating through cyclotron resonance. Wave generation at UHR and parametric decay at high power has been observed during Electron Cyclotron Resonance (ECR) heating experiments in toroidal magnetic fusion devices. A small linear system with ECR and UHR layer within the system has been used to conduct experiments on X-B conversion and parametric decay process as a function of system parameters. Direct probing {\em in situ} is conducted and plasma heating is evidenced by soft x-ray emission measurement. Experiments are performed with hydrogen plasma produced with 160-800 W microwave power at 2.45 GHz of operating frequency at $10^{-3}$ mbar pressure. The axial magnetic field required for ECR is such that the resonant surface (B = 875 G) is situated at the geometrical axis of the plasma system. Experimental results will be presented in the paper.Comment: 12th International Congress on Plasma Physics, 25-29 October 2004, Nice (France

1/f noise in nanowires

We have measured the low-frequency resistance fluctuations (1 mHz<f<10 Hz) in Ag nanowires of diameter 15 nm<d<200 nm at room temperatures. The power spectral density (PSD) of the fluctuations has a 1/f^{\alpha} character as seen in metallic films and wires of larger dimension. Additionally, the PSD has a significant low-frequency component and the value of \alpha increases from the usual 1 to ~3/2 as the diameter d is reduced. The value of the normalized fluctuation \frac{}{R^2} also increases as the diameter d is reduced. We observe that there are new features in the 1/f noise as the size of the wire is reduced and they become more prominent as the diameter of the wires approaches 15nm. It is important to investigate the origin of the new behavior as 1/f noise may become a limiting factor in the use of metal wires of nanometer dimensions as interconnects.Comment: 9 pages, 6 figures, published in Nanotechnolog

Resolving Octant Degeneracy at LBL experiment by combining Daya Bay Reactor Setup

Long baseline Experiment (LBL) have promised to be a very powerful experimental set up to study various issues related to Neutrinos. Some ongoing and planned LBL and medium baseline experiments are - T2K, MINOS, NOvA, LBNE, LBNO etc. But the long baseline experiments are crippled due to presence of some parameter degeneracies, like the Octant degeneracy. In this work, we first show the presence of Octant degeneracy in LBL experiments, and then combine it with Daya Bay Reactor experiment, at different values of CP violation phase. We show that the Octant degeneracy in LBNE can be resolved completely with this proposal.Comment: 4 pages, 8 figure

Hematite and its hybrid nanostructures for photoelectrochemical water splitting: how do properties affect functionality?

The concept of water splitting in photo-electrochemical cells (PEC) dates back to 1972 when Fujishima and Honda developed the titania electrode which splits water into H2 and O2 under the presence of light and bias. The water splitting reaction is well established in nature. For instance, green plants and cyanobacteria used this water splitting machinery to run the very important photosynthetic process. Hematite films are suitable for PEC because of their stability, suitable band gap, and energy band positions. I have dedicated my PhD thesis to this field and will present here my results. The final PEC properties of the films have been studied by running current vs. potential measurement and it is found that one dip coated layer gives rise to around 250 μA /cm2. Optimization of their photocurrent densities has been achieved either through doping or by morphological modification. Doping with silicon resulted in the formation of dendritic nanostructures and a significant increase in the incident photon to- current conversion efficiency of 42% at 320 nm wavelength. Following this, Si doping have been performed and it is found that 0.5% silicon doped hematite film showing maximum photocurrent density of around 2.4 mA/cm2. After this surface modification strategy has been employed in order to get hybrid nanostructure. In this regard, a simple one pot hydrothermal method is described for converting a dip coated hematite nanoparticulate film into an array of nanorods with superimposed flower like structures suitable for the water splitting in photoelectrochemical cells. The hydrothermal treatment of the dip-coated hematite film with FeCl3•6H2O and L – Arginine enhances the photocurrent by a factor of two. The photocurrent density of the pristine film reached 218 μA /cm2 after 48 hours of hydrothermal treatment and this increase was attributed to the higher specific surface area of the modified film and changes in the optical properties pristine film after hydrothermal treatment. Another way of increasing the photocurrent of hematite by covalent cross-coupling with phycocyanin has been developed. For this, a hematite – phycocyanin integrated system is assembled by consecutive adsorption and cross coupling of protein molecules separated by an agarose layer and a linker molecule on the top of a mesoporous hematite film. The hematite - phycocyanin assembly shows a two-fold increased photocurrent in comparison with the pristine hematite film. The increase in the photocurrent is attributed to the enhanced light absorbing of the hematite film after integration with protein, as is evident from the UV-Vis spectra and from the photocurrent action spectrum. The assembly shows long term stability and thus constitutes a promising hybrid photoanode for photoelectrochemical applications. Finally, a multiple band gap photoelectrode was fabricated by employing the hydrothermal deposition of NiO nanostructure on the top of hematite electrode. This system showed good gas evolution and a current density of around 16 mA /cm2 and systems works by the redox reaction of Ni and Fe

Estimate of CP Violation for the LBNE Project and $\delta_{CP}

Measurements of CP violation (CPV) and the basic $\delta_{CP}$ parameter are the goals of the LBNE Project, which is being planned. Using the expected energy and baseline parameters for the LBNE Project, CPV and the dependence of CPV on $\delta_{CP}$ are estimated, to help in the planning of this project.Comment: 7 pages, 1 figur

Scanning thermal microscope study of a metal film under current stressing: role of temperature inhomogeneity in the damage process

We report direct observation of the evolution of local temperature inhomogeneity and the resulting atomic migration in a metal film (Ag on Si) stressed by a high electrical current is reported. Experiments were carried out by simultaneous temperature mapping and topography imaging using a scanning thermal microscope in combination with resistance measurements. The experimental observation is analysed using a model based simulation. The experimental observation and the simulation show that due to current stressing the temperature of the film becomes significantly inhomogeneous over time (with the local temperature deviating strongly from the mean). This creates local stress as well as local temperature gradients (as high as &#8776;3 &#956;m&#8722;1) that lead to mass migration in addition to electromigration. The local temperature inhomogeneity serves as one of the main agents for local atomic migration which leads to a change in the film microstructure. The migration leads to damage and eventual failure as simultaneously monitored by in situ resistance measurements

Field application of anabolic steroids in carp seed production. II. Rearing of spawn to fry stage.

Two synthetic androgenic steroids, Ethylestrenol (17 β - Hydroxy - 17 α ethyl - estr - 4 - en - 3 - one) and Stanozolal (17 β - Hydroxy- 17 α - methyl - 5 a - androstano - 3, 2 - C - pyrazole) were fed via diet at 3 ppm to the spawn of Rohu and Mrigal which were reared up to fry stage over a period of 15 days in earthen carp nurseries. Both hormones enhanced growth of spawn. A maximum of 25.78% increase in length and 25.69% increase in weight as compared to the controls has been recorded. Growth rate was recorded to be 0.8 mm & 2.48 mg/day (control), and 1.13 mm & 2.67 mg/day (Stanozolol treated) in case of Mrigal spawn; and 0.91 mm & 2.39 mg/day (control), 1.12 mm & 2.90 mg/day (Ethylestrenol treated), and 1.10 mm & 2.57 mg/day (Stanozolol treated) in case of Rohu spawn. A decrease in the values of Relative Condition Factor upon hormone administration was also noticed