7,211 research outputs found
Inhomogeneous vortex-state-driven enhancement of superconductivity in nanoengineered ferromagnet-superconductor heterostructures
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
Tunneling spectroscopy measurements have been carried out on a single
molecule device formed by two Pd nanocrystals (dia, 5 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 0.67 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 (0.3 V).Comment: Accepted in Praman
An Experimental Study on Performance of Sugarcane Bioethanol blend on VCR Engine
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
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
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
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
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
This work was supported
by funding from Biogen, including funding for the
editorial and writing support in the the development of
this paper
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