7,211 research outputs found

    Inhomogeneous vortex-state-driven enhancement of superconductivity in nanoengineered ferromagnet-superconductor heterostructures

    Get PDF
    Thin film heterostructures provide a powerful means to study the antagonism between superconductivity (SC) and ferromagnetism (FM). One interesting issue in FM-SC hybrids which defies the notion of antagonistic orders is the observation of magnetic field induced superconductivity (FIS). Here we show that in systems where the FM domains/islands produce spatial inhomogeneities of the SC order parameter, the FIS can derive significant contribution from different mobilities of the magnetic flux identified by two distinct critical states in the inhomogeneous superconductor. Our experiments on nanoengineered bilayers of ferromagnetic CoPt and superconducting NbN where CoPt/NbN islands are separated by a granular NbN, lend support to this alternative explanation of FIS in certain class of FM-SC hybrids.Comment: 5 figure

    A single molecule switch based on two Pd nanocrystals linked by a conjugated dithiol

    Get PDF
    Tunneling spectroscopy measurements have been carried out on a single molecule device formed by two Pd nanocrystals (dia, \sim5 nm) electronically coupled by a conducting molecule, dimercaptodiphenylacetylene. The I-V data, obtained by positioning the tip over a nanocrystal electrode, exhibit negative differential resistance (NDR) on a background M-I-M characteristics. The NDR feature occurs at \sim0.67 V at 300 K and shifts to a higher bias of 1.93 V at 90 K. When the tip is held in the middle region of the device, a coulomb blockade region is observed (±\pm\sim0.3 V).Comment: Accepted in Praman

    An Experimental Study on Performance of Sugarcane Bioethanol blend on VCR Engine

    Get PDF
    Biofuels are a wide ranged of fuels which are in some way derives  from biomass. Biofuels are gaining increased public and scientific attention, driven by  factored such as oil price spikes, the need for increased energies securities and concern over greenhouse gas emissions from fossil fuels. Biofuels have become particularly appealing to developing countries because of their potentially to stimulate economics development in rural area and eradicate poverty through the recreates of employment opportunities and increased incomes in agricultural sector

    Metallicity Evolution of Damped Lyman-Alpha Galaxies

    Full text link
    We have reanalyzed the existing data on Zinc abundances in damped Ly-alpha (DLA) absorbers to investigate whether their mean metallicity evolves with time. Most models of cosmic chemical evolution predict that the mass- weighted mean interstellar metallicity of galaxies should rise with time from a low value ~ 1/30 solar at z ~ 3 to a nearly solar value at z ~ 0. However, several previous analyses have suggested that there is little or no evolution in the global metallicity of DLAs. We have used a variety of statistical techniques to quantify the global metallicity-redshift relation and its uncertainties, taking into account both measurement and sampling errors. Three new features of our analysis are: (a) an unbinned N(H I)-weighted nonlinear chi-square fit to an exponential relation; (b) survival analysis to treat the large number of limits in the existing data; and (c) a comparison of the data with several models of cosmic chemical evolution based on an unbinned N(H I)-weighted chi-square. We find that a wider range of evolutionary rates is allowed by the present data than claimed in previous studies. The slope of the exponential fit to the N(H I)-weighted mean Zn metallicity vs. redshift relation is -0.20 plus minus 0.11 counting limits as detections and -0.27 plus minus 0.12 counting limits as zeros. Similar results are also obtained if the data are binned in redshift, and if survival analysis is used. These slopes are marginally consistent with no evolution, but are also consistent with the rates predicted by several models of cosmic chemical evolution. Finally, we outline some future measurements necessary to improve the statistics of the global metallicity-redshift relation.Comment: 25 pages, 1 figure, accepted for publication in the Astrophysical Journa

    Effect on strength of Involute spur gear tooth by considering Uncertainties in Geometry and Material propertiesby using Finite Element Methods-A Review

    Get PDF
    Gearing is the special division of Mechanical Engineering concerned with the transmission of power and motion between the rotating shafts. Gears not only transmit motion and enormous power satisfactorily, but can do so with very uniform motion. It is the best and the economical means of achieving this transmission. Gear teeth fail due to the static and the dynamic loads acting over it. This paper presents study of effect of various parameters on beam strength of involute spur gear tooth. The effect on strength of involute spur gear tooth is studied by considering uncertainties in geometric parameters like fillet radius, face width etc. Also the uncertainties in material properties which affect strength of involute spur gear tooth are studied

    Mechanisms of rolling contact spalling

    Get PDF
    The results of a study aimed at analyzing the mechanical material interactions responsible for rolling contact spalling of the 440 C steel, high pressure oxygen turbopump bearings are presented. A coupled temperature displacement finite element analysis of the effects of friction heating under the contact is presented. The contact is modelled as a stationary, heat generating, 2 dimensional indent in an elastic perfectly plastic half-space with heat fluxes up to 8.6 x 10000 KW/m sq comparable to those generated in the bearing. Local temperatures in excess of 1000 C are treated. The calculations reveal high levels of residual tension after the contact is unloaded and cools. Efforts to promote Mode 2/Mode 3 fatigue crack growth under cyclic torsion in hardened 440 C steel are described. Spalls produced on 440 C steel by a 3 ball/rod rolling contact testing machine were studied with scanning microscopy. The shapes of the cyclic, stress strain hysteresis loops displayed by hardened 440 C steel in cyclic torsion at room temperature are defined for the plastic strain amplitudes encountered in rolling/sliding contact. Results of these analyses are discussed in detail

    Towards a public analysis database for LHC new physics searches using MadAnalysis 5

    Get PDF
    We present the implementation, in the MadAnalysis 5 framework, of several ATLAS and CMS searches for supersymmetry in data recorded during the first run of the LHC. We provide extensive details on the validation of our implementations and propose to create a public analysis database within this framework.Comment: 20 pages, 15 figures, 5 recast codes; version accepted by EPJC (Dec 22, 2014) including a new section with guidelines for the experimental collaborations as well as for potential contributors to the PAD; complementary information can be found at http://madanalysis.irmp.ucl.ac.be/wiki/PhysicsAnalysisDatabas

    Recombinant factorVIII Fc fusion protein for the prevention and treatment of bleeding in children with severe hemophilia A

    Get PDF
    This work was supported by funding from Biogen, including funding for the editorial and writing support in the the development of this paper
    corecore