11,592 research outputs found
On dispersion and characteristic motions of temperature rate dependent materials
Three dimensional theory of thermomechanical material developed using techniques of continuum mechanics and law of thermodynamic
Magnetic field induced singlet - triplet phase transition in quasi one-dimensional organic superconductors
We propose a theoretical model of quasi-one-dimensional superconductors, with
attractive electron-electron interactions dominant in the singlet d-wave
channel and sub-dominant in the p-wave channel. We discuss, in the mean field
approximation, the effect of a magnetic field applied perpendicularly to the
direction of the lowest conductivity. The lowest free energy phase corresponds
to a singlet d-wave symmetry in low fields, but to a triplet symmetry in high
fields. A first order singlet-triplet phase transition is expected at moderate
applied fields of a few teslas. We propose to ascribe the recent critical field
and NMR experimental data, observed in superconducting (TMTSF)2ClO4 to such an
effect.Comment: 6 pages, 2 figures, accepted in EP
On Negotiation as Concurrency Primitive
We introduce negotiations, a model of concurrency close to Petri nets, with
multiparty negotiation as primitive. We study the problems of soundness of
negotiations and of, given a negotiation with possibly many steps, computing a
summary, i.e., an equivalent one-step negotiation. We provide a complete set of
reduction rules for sound, acyclic, weakly deterministic negotiations and show
that, for deterministic negotiations, the rules compute the summary in
polynomial time
meson effects on neutron stars in the modified quark-meson coupling model
The properties of neutron stars are investigated by including meson
field in the Lagrangian density of modified quark-meson coupling model. The
population with meson is larger than that without
meson at the beginning, but it becomes smaller than that without meson
as the appearance of . The meson has opposite effects on
hadronic matter with or without hyperons: it softens the EOSes of hadronic
matter with hyperons, while it stiffens the EOSes of pure nucleonic matter.
Furthermore, the leptons and the hyperons have the similar influence on
meson effects. The meson increases the maximum masses of
neutron stars. The influence of on the meson effects
are also investigated.Comment: 10 pages, 6 figures, 4 table
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School nurses' involvement, attitudes and training needs for mental health work: a UK-wide cross-sectional study
Aim.  The aim of this study was to identify school nurses’ views concerning the mental health aspects of their role, training requirements and attitudes towards depression in young people.
Background.  Mental health problems in children and young people have high prevalence worldwide; in the United Kingdom they affect nearly 12% of secondary school pupils. School nurses have a wide-ranging role, and identifying and managing mental health problems is an important part of their work
Methods.  A cross-sectional study was conducted using a postal questionnaire sent to a random sample of 700 school nurses throughout the United Kingdom in 2008. Questions concerned involvement in mental health work and training needs for this work. Attitudes were measured using the Depression Attitude Questionnaire
Results.  Questionnaires were returned by 258 (37%) nurses. Nearly half of respondents (46%) had not received any postregistration training in mental health, yet 93% agreed that this was an integral part of their job. Most (55%) noted that involvement with young people’s psychological problems occupied more than a quarter of their work time. Staff attitudes were broadly similar to those of other primary care professionals, and indicated a rejection of stigmatizing views of depression and strong acknowledgement of the role of the school nurse in providing support.
Conclusion.  Working with young people who self-harm, and recognizing and being better equipped to assist in managing depression and anxiety are key topics for staff development programmes
First measurements of the flux integral with the NIST-4 watt balance
In early 2014, construction of a new watt balance, named NIST-4, has started
at the National Institute of Standards and Technology (NIST). In a watt
balance, the gravitational force of an unknown mass is compensated by an
electromagnetic force produced by a coil in a magnet system. The
electromagnetic force depends on the current in the coil and the magnetic flux
integral. Most watt balances feature an additional calibration mode, referred
to as velocity mode, which allows one to measure the magnetic flux integral to
high precision. In this article we describe first measurements of the flux
integral in the new watt balance. We introduce measurement and data analysis
techniques to assess the quality of the measurements and the adverse effects of
vibrations on the instrument.Comment: 7 pages, 8 figures, accepted for publication in IEEE Trans. Instrum.
Meas. This Journal can be found online at
http://ieeexplore.ieee.org/xpl/RecentIssue.jsp?punumber=1
Applicability of Modified Effective-Range Theory to positron-atom and positron-molecule scattering
We analyze low-energy scattering of positrons on Ar atoms and N2 molecules
using Modified Effective-Range Theory (MERT) developped by O'Malley, Spruch and
Rosenberg [Journal of Math. Phys. 2, 491 (1961)]. We use formulation of MERT
based on exact solutions of Schroedinger equation with polarization potential
rather than low-energy expansions of phase shifts into momentum series. We show
that MERT describes well experimental data, provided that effective-range
expansion is performed both for s- and p-wave scattering, which dominate in the
considered regime of positron energies (0.4 - 2 eV). We estimate the values of
the s-wave scattering lenght and the effective range for e+ - Ar and e+ - N2
collisions.Comment: RevTeX, 4 pages, 2 figure
Non deterministic Repairable Fault Trees for computing optimal repair strategy
In this paper, the Non deterministic Repairable Fault Tree (NdRFT) formalism is proposed: it allows to model failure modes of complex systems as well as their repair processes. The originality of this formalism
with respect to other Fault Tree extensions is that it allows to face repair strategies optimization problems: in an NdRFT model, the decision on whether to start or not a given repair action is non deterministic, so
that all the possibilities are left open. The formalism is rather powerful allowing to specify which failure events are observable, whether local repair or global repair can be applied, and the resources needed to start
a repair action. The optimal repair strategy can then be computed by solving an optimization problem on a Markov Decision Process (MDP) derived from the NdRFT. A software framework is proposed in order to perform in automatic way the derivation of an MDP from a NdRFT model, and to deal with the solution of the MDP
Tungsten nuclear rocket, phase I, part 1 Final report
Tungsten water moderated nuclear rocket reactor experiments and analyse
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