1,761 research outputs found
High-strength tungsten alloy with improved ductility
Alloy combines superior strength at elevated temperatures with improved ductility at lower temperatures relative to unalloyed tungsten. Composed of tungsten, rhenium, hafnium, and carbon, the alloy is prepared by consumable electrode vacuum arc-melting and can be fabricated into rod, plate, and sheet
The mechanical response of semiflexible networks to localized perturbations
Previous research on semiflexible polymers including cytoskeletal networks in
cells has suggested the existence of distinct regimes of elastic response, in
which the strain field is either uniform (affine) or non-uniform (non-affine)
under external stress. Associated with these regimes, it has been further
suggested that a new fundamental length scale emerges, which characterizes the
scale for the crossover from non-affine to affine deformations. Here, we extend
these studies by probing the response to localized forces and force dipoles. We
show that the previously identified nonaffinity length [D.A. Head et al. PRE
68, 061907 (2003).] controls the mesoscopic response to point forces and the
crossover to continuum elastic behavior at large distances.Comment: 16 pages, 18 figures; substantial changes to text and figures to
clarify the crossover to continuum elasticity and the role of finite-size
effect
Incompatibility of the Digital Economy Act 2010 subscriber appeal process provisions with Article 6 of the ECHR
This is the accepted manuscript of an article published by Taylor & Francis in International Review of Law, Computers and Technology on 10 January 2014. The version of record [Romero-Moreno, F. (2014) Incompatibility of the Digital Economy Act 2010 subscriber appeal process provisions with Article 6 of the ECHR', International Review of Law, Computers & Technology, 28(1): 81-97, first published on line January 10, 2014] is available online via doi: http://dx.doi.org/10.1080/13600869.2013.869912Through case-law research, this paper critically assesses the compatibility of the Digital Economy Act 2010 (DEA) subscriber appeal process provisions (Section 13 of the DEA) with Article 6 of the European Convention on Human Rights (ECHR). Drawing on the European Court of Human Rights (ECtHR) case-law, Ofcom's Initial Obligations Code (the Code), and the DEA judicial review decision, namely, BT PLC and Talk Talk PLC v Secretary of State for Business Innovation and Skills and others, this paper focuses on the three Strasbourg Court principles of equality of arms, admissibility of evidence, and presumption of innocence, in an effort to determine whether Section 13 of the DEA infringes them, and whether this constitutes a breach of a subscriber's right to a fair trial under Article 6 of the ECHR. The paper examines these three ECtHR principles. It contrasts such principles with the Code's provisions, and considers the compatibility of Section 13 of the DEA with Article 6 of the ECHR. It concludes that the DEA subscriber appeal process provisions do indeed infringe these principles, thus constituting a violation of subscribers' right to a fair trial. It also recommends that the UK government start taking seriously human rights in general, and Article 6 of the ECHR in particular.Peer reviewe
Indeterminacy of Spatiotemporal Cardiac Alternans
Cardiac alternans, a beat-to-beat alternation in action potential duration
(at the cellular level) or in ECG morphology (at the whole heart level), is a
marker of ventricular fibrillation, a fatal heart rhythm that kills hundreds of
thousands of people in the US each year. Investigating cardiac alternans may
lead to a better understanding of the mechanisms of cardiac arrhythmias and
eventually better algorithms for the prediction and prevention of such dreadful
diseases. In paced cardiac tissue, alternans develops under increasingly
shorter pacing period. Existing experimental and theoretical studies adopt the
assumption that alternans in homogeneous cardiac tissue is exclusively
determined by the pacing period. In contrast, we find that, when calcium-driven
alternans develops in cardiac fibers, it may take different spatiotemporal
patterns depending on the pacing history. Because there coexist multiple
alternans solutions for a given pacing period, the alternans pattern on a fiber
becomes unpredictable. Using numerical simulation and theoretical analysis, we
show that the coexistence of multiple alternans patterns is induced by the
interaction between electrotonic coupling and an instability in calcium
cycling.Comment: 20 pages, 10 figures, to be published in Phys. Rev.
Coupled dynamics of voltage and calcium in paced cardiac cells
We investigate numerically and analytically the coupled dynamics of
transmembrane voltage and intracellular calcium cycling in paced cardiac cells
using a detailed physiological model and its reduction to a three-dimensional
discrete map. The results provide a theoretical framework to interpret various
experimentally observed modes of instability ranging from electromechanically
concordant and discordant alternans to quasiperiodic oscillations of voltage
and calcium
MOST detects variability on tau Bootis possibly induced by its planetary companion
(abridged) There is considerable interest in the possible interaction between
parent stars and giant planetary companions in 51 Peg-type systems. We
demonstrate from MOST satellite photometry and Ca II K line emission that there
has been a persistent, variable region on the surface of tau Boo A which
tracked its giant planetary companion for some 440 planetary revolutions and
lies ~68deg (phi=0.8) in advance of the sub-planetary point. The light curves
are folded on a range of periods centered on the planetary orbital period and
phase dependent variability is quantified by Fourier methods and by the mean
absolute deviation (MAD) of the folded data for both the photometry and the Ca
II K line reversals. The region varies in brightness on the time scale of a
rotation by ~1 mmag. In 2004 it resembled a dark spot of variable depth, while
in 2005 it varied between bright and dark. Over the 123 planetary orbits
spanned by the photometry the variable region detected in 2004 and in 2005 are
synchronised to the planetary orbital period within 0.0015 d. The Ca II K line
in 2001, 2002 and 2003 also shows enhanced K-line variability centered on
phi=0.8, extending coverage to some 440 planetary revolutions. The apparently
constant rotation period of the variable region and its rapid variation make an
explanation in terms of conventional star spots unlikely. The lack of
complementary variability at phi=0.3 and the detection of the variable region
so far in advance of the sub-planetary point excludes tidal excitation, but the
combined photometric and Ca II K line reversal results make a good case for an
active region induced magnetically on the surface of tau Boo A by its planetary
companion.Comment: 7 pages, 7 figures; accepted for publication in A&
Dimensionality dependent electronic structure of the exfoliated van der Waals antiferromagnet NiPS
Resonant Inelastic X-ray Scattering (RIXS) was used to measure the local
electronic structure in few-layer exfoliated flakes of the van der Waals
antiferromagnet NiPS. The resulting spectra show a systematic softening and
broadening of multiplet excitations with decreasing layer count from
the bulk to three atomic layers (3L). These trends are driven by a decrease in
the transition metal-ligand and ligand-ligand hopping integrals, and in the
charge-transfer energy: = 0.60 eV in the bulk and 0.22 eV in 3L
NiPS. Relevant intralayer magnetic exchange integrals computed from the
electronic parameters exhibit a systematic decrease in the average interaction
strength with thickness and place 2D NiPS close to the phase boundary
between stripy and spiral antiferromagnetic order, which may explain the
apparent vanishing of long-range order in the 2D limit. This study explicitly
demonstrates the influence of layer electronic interactions on
layer ones in insulating magnets. As a consequence, the magnetic
Hamiltonian in few-layer insulating magnets can be significantly different from
that in the bulk.Comment: 5 pages, 4 figures; additional 9 pages and 13 figures of
supplementary informatio
Measuring the Quantum State of a Large Angular Momentum
We demonstrate a general method to measure the quantum state of an angular
momentum of arbitrary magnitude. The (2F+1) x (2F+1) density matrix is
completely determined from a set of Stern-Gerlach measurements with (4F+1)
different orientations of the quantization axis. We implement the protocol for
laser cooled Cesium atoms in the 6S_{1/2}(F=4) hyperfine ground state and apply
it to a variety of test states prepared by optical pumping and Larmor
precession. A comparison of input and measured states shows typical
reconstruction fidelities of about 0.95.Comment: 4 pages, 6 figures, submitted to PR
Planetary vehicle thermal insulation systems Final report
Goldized Mylar or Kapton and other materials for planetary vehicle thermal insulation system
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