Effect of heat treatment on the sliding wear behaviour of aluminium alloy (Al–Zn–Mg) hard particle composite

Effect of heat treatment on the sliding wear behaviour of aluminium alloy hard particle composite was studied under varying applied load and sliding speed, giving emphasis on the parameters such as wear rate, temperature rise, coefficient of friction and seizure pressure. Hardness is improved due to heat treatment irrespective of the material. Maximum hardness is noted when the materials are aged for 6 h. These facts have been discussed on the basis of nature of worn surface produced after wear. In the present investigation, aging time has been varied from 4 to 10 h at a regular increment of 2 h.     

All-optical packet switching for metropolitan area networks:opportunities and challenges

The fast evolution of networks has been continuously driven by new advances in enabling technologies, as well as the growth of Internet traffic. All-optical packet switching provides high throughput, rich routing functionalities, and excellent flexibility. These characteristics make it an excellent candidate for next-generation metropolitan area networks, which will be much more dynamic and demanding than today's networks. In this article we not only discuss some of the architectural challenges involved in the design of all-optical packet switched networks, but also present the reader a high-level picture of how such future networks could be integrated with other network segments, to provide users end-to-end connectivity with performance and simplicity     

Drying of Multilayer Polymeric Coatings,Part I: An Experimental Study

Designing of multilayer coatings of poly(styrene)-tetrahydrofuran and poly(methyl methacrylate)-tetrahydrofuran has been studied. Multilayers were prepared by layer-by-layer and simultaneous methods. Several binary polymeric coatings of poly(styrene)-tetrahydrofuran and poly(methyl methacrylate)-tetrahydrofuran systems have been dried under quiescent drying conditions. Gravimetric analyses were performed using an analytical weighing balance. The initial amount of polymer was kept constant in both solution coatings. Coating which is likely to go through the glass transition temperature should be applied on the bottom side in order to minimize the residual solvent. For instance, residual solvent content is high in multilayer coating having poly(methyl methacrylate)-tetrahydrofuran coating on the top and poly(styrene)-tetrahydrofuran coating on the bottom, as compared to multilayer coatings having poly(styrene)-tetrahydrofuran on the top of poly(methyl methacrylate)-tetrahydrofuran coating.     

The first measurements of soft x-ray flux from ignition scale Hohlraums at the National Ignition Facility using DANTE (invited)

The first 96 and 192 beam vacuum Hohlraum target experiments have been fielded at the National Ignition Facility demonstrating radiation temperatures up to 340 eV and fluxes of 20 TW/sr as viewed by DANTE representing an ～20?times flux increase over NOVA/Omega scale Hohlraums. The vacuum Hohlraums were irradiated with 2 ns square laser pulses with energies between 150 and 635 kJ. They produced nearly Planckian spectra with about 30±10% more flux than predicted by the preshot radiation hydrodynamic simulations. To validate these results, careful verification of all component calibrations, cable deconvolution, and software analysis routines has been conducted. In addition, a half Hohlraum experiment was conducted using a single 2 ns long axial quad with an irradiance of ～2×10(15)?W/cm(2) for comparison with NIF Early Light experiments completed in 2004. We have also completed a conversion efficiency test using a 128-beam nearly uniformly illuminated gold sphere with intensities kept low (at 1×10(14)?W/cm(2) over 5 ns) to avoid sensitivity to modeling uncertainties for nonlocal heat conduction and nonlinear absorption mechanisms, to compare with similar intensity, 3 ns OMEGA sphere results. The 2004 and 2009 NIF half-Hohlraums agreed to 10% in flux, but more importantly, the 2006 OMEGA Au Sphere, the 2009 NIF Au sphere, and the calculated Au conversion efficiency agree to ±5% in flux, which is estimated to be the absolute calibration accuracy of the DANTEs. Hence we conclude that the 30±10% higher than expected radiation fluxes from the 96 and 192 beam vacuum Hohlraums are attributable to differences in physics of the larger Hohlraums.     

Quantum dot encapsulation in viral capsids

Incorporation of CdSe/ZnS semiconductor quantum dots (QDs) into viral particles provides a new paradigm for the design of intracellular microscopic probes and vectors. Several strategies for the incorporation of QDs into viral capsids were explored; those functionalized with poly(ethylene glycol) (PEG) can be self-assembled into viral particles with minimal release of photoreaction products and enhanced stability against prolonged irradiation.     

Bioremediation potential of genus Portulaca L. collected from industrial areas in Vadodara, Gujarat, India

During the present study, two species of Portulaca, i.e., P. tuberosa and P. oleracea were collected from two field sites in Vadodara, Gujarat, India; one irrigated with industrial effluent and other with tube well water, and were analyzed for heavy metal accumulation in different plant parts viz., roots, stem, leaves, and flowers. Plants collected from effluent irrigated areas showed high accumulation of all the investigated heavy metals in all plant parts with the maximum being in roots and the least in flowers. Interestingly, both species of Portulaca demonstrated hyperaccumulation of multiple elements viz., Cu, Ni, Hg, and Pb. The total shoot concentrations (μg g⁻¹ dw) of Cu, Ni, Hg, and Pb in P. tuberosa were 1538, 1191, 789, and 2744, respectively, while in P. oleracea, these were 1940, 1542, 534, and 2312, respectively. Besides this, selective hyperaccumulation of Se (2,327 μg g⁻¹ dw) and Al (1,164 μg g⁻¹ dw) was shown by P. tuberosa and P. oleracea, respectively. Total shoot concentrations (μg g⁻¹ dw) of Mo were about 399 and 668 in P. tuberosa and P. oleracea, respectively. Overall, P. oleracea accumulated higher amounts of multiple metals from industrial effluent contaminated site, hence appears to be a suitable candidate for phytoremediation purposes of metal contaminated areas.     

Analysis on the saturation of refractive index modulation in fiber Bragg gratings (FBGs) written by partially coherent UV beams

We present an analysis on the saturation of refractive index modulation of fiber Bragg gratings written in nonhydrogenated Ge-B co-doped single-mode photosensitive optical fiber by partially coherent pulsed UV beams. The UV beams of different spatial coherence properties were generated by second harmonic conversion of high repetition rate, high average power copper vapor laser (CVL) oscillators with different optical resonators. It is observed that for UV beams of higher spatial coherence, the fiber Bragg grating reflectivity growth was faster and saturation of refractive index modulation was higher. The experimental results are explained with the help of a physical model based on exponential decay of defect centers per unit volume on UV absorption in the fiber core. The subsequent increase in the refractive index was attributed to the structural modification and densification of the fiber core.     

Analysis of the parasitic S/D resistance in multiple-gate FETs

The multiple-gate field-effect transistor (FET) is a promising device architecture for the 45-nm CMOS technology node. These nonplanar devices suffer from a high parasitic resistance due to the narrow width of their source/drain (S/D) regions. We analyze the parasitic S/D resistance behavior of the multiple-gate FETs using a novel, S/D geometry-based analytical model, which is validated using three-dimensional device simulations and experimental results. The model predicts limits to parasitic S/D resistance scaling, which reveal that the contact resistance between the S/D silicide and Si-fin dominates the parasitic S/D resistance behavior of multiple-gate FETs. It is shown that the selective epitaxial growth of Si on S/D regions alone may be insufficient to meet the semiconductor roadmap target for parasitic S/D resistance at the 45-nm CMOS technology node.     

Resource potential and scope of utilization of renewable energy in Jammu and Kashmir, India

Jammu and Kashmir the northern most state of India is blessed with immense potential for utilization of renewable energy. The state at present is fairly untapped in terms of energy utilization and thus venturing into this region would definitely prove to be profitable. The natural energy sources like sunshine, wind, vegetation, water flow, biomass and other biological wastes though abundantly available in the state yet are not being potentially harnessed resulting in very low per capita energy availability, deforestation and poor health. Renewable energy acquires a promising option not only for energy availability next view and of environment protection but also the socio-economic conditions of the people residing in these areas can be improved to a great extent. The hydroelectric power has tremendous potential for generation of electricity in the state because the topography of the state provides extensive network of canals and streams. This paper describes the resource potential and opportunity to enter the market and bring more renewable energy projects in the form of solar, biomass derived fuels, biogas and hydroelectric in the state.