25,317 research outputs found
Estimated Surface Motions of the Earth's Core
Estimated surface fluid motions of earth core, and rotational and irrotational flow dat
Comparison of estimates of surface fluid motions of the earth's core various epochs
Method of determining velocity of surface fluid motions of earth core for various epoch
Nature of surface flow in the earth's central core
Nonuniform fluid velocity effect at surface of earth core on nature of surface flo
A simple solution of sound transmission through an elastic wall to a rectangular enclosure, including wall damping and air viscosity effects
A simple solution to the problem of the acoustical coupling between a rectangular structure, its air content, and an external noise source is presented. This solution is a mathematical expression for the normalized acoustic pressure inside the structure. Numerical results for the sound-pressure response for a specified set of parameters are also presented
Incompatible sets of gradients and metastability
We give a mathematical analysis of a concept of metastability induced by
incompatibility. The physical setting is a single parent phase, just about to
undergo transformation to a product phase of lower energy density. Under
certain conditions of incompatibility of the energy wells of this energy
density, we show that the parent phase is metastable in a strong sense, namely
it is a local minimizer of the free energy in an neighbourhood of its
deformation. The reason behind this result is that, due to the incompatibility
of the energy wells, a small nucleus of the product phase is necessarily
accompanied by a stressed transition layer whose energetic cost exceeds the
energy lowering capacity of the nucleus. We define and characterize
incompatible sets of matrices, in terms of which the transition layer estimate
at the heart of the proof of metastability is expressed. Finally we discuss
connections with experiment and place this concept of metastability in the
wider context of recent theoretical and experimental research on metastability
and hysteresis.Comment: Archive for Rational Mechanics and Analysis, to appea
Light-cone sum rules for form factors revisited
We reconsider and update the QCD light-cone sum rules for form
factors. The gluon radiative corrections to the twist-2 and twist-3 terms in
the correlation functions are calculated. The -quark mass is
employed, instead of the one-loop pole mass used in the previous analyses. The
light-cone sum rule for is fitted to the measured
-distribution in , fixing the input parameters with the
largest uncertainty: the Gegenbauer moments of the pion distribution amplitude.
For the vector form factor at zero momentum transfer we predict
. Combining it with the value of the
product extracted from experiment, we obtain
. In addition, the scalar
and penguin form factors and are
calculated.Comment: 33 pages, 7 figures, one figure and a few comments added, version to
appear in JHE
The Legacy of ERA, Privatization and the Policy Ratchet
This article explores the ways in which the neo-liberal impetus toward the privatization of state schooling signalled in the Education Reform Act 1988 (ERA) has become embedded in the English school system. Four main points are made. First, that ERA itself was of huge strategic rather than substantive importance as far as privatization is concerned. Second, by tracing the lineage of privatization from ERA onwards a 'ratchet' effect of small and incremental policy moves can be identified, which have disseminated, embedded and naturalized privatization within public sector provision. Third, that while privatization has been taken up and taken much further by New Labour than it had been by the Conservatives there are differences between the two sets of governments in the role of privatization in education policy and the role of the state. Fourth, the participation of private providers in the planning and delivery of state services has put the private sector at the very heart of policy. At points the article draws upon interviews conducted with private sector providers. © 2008 Sage Publications
Measuring the Magnetic Flux Density in the CMS Steel Yoke
The Compact Muon Solenoid (CMS) is a general purpose detector, designed to
run at the highest luminosity at the CERN Large Hadron Collider (LHC). Its
distinctive features include a 4 T superconducting solenoid with 6-m-diameter
by 12.5-m-length free bore, enclosed inside a 10000-ton return yoke made of
construction steel. The return yoke consists of five dodecagonal three-layered
barrel wheels and four end-cap disks at each end comprised of steel blocks up
to 620 mm thick, which serve as the absorber plates of the muon detection
system. Accurate characterization of the magnetic field everywhere in the CMS
detector is required. To measure the field in and around the steel, a system of
22 flux-loops and 82 3-D Hall sensors is installed on the return yoke blocks.
Fast discharges of the solenoid (190 s time-constant) made during the CMS
magnet surface commissioning test at the solenoid central fields of 2.64, 3.16,
3.68 and 4.01 T were used to induce voltages in the flux-loops. The voltages
are measured on-line and integrated off-line to obtain the magnetic flux in the
steel yoke close to the muon chambers at full excitations of the solenoid. The
3-D Hall sensors installed on the steel-air interfaces give supplementary
information on the components of magnetic field and permit to estimate the
remanent field in steel to be added to the magnetic flux density obtained by
the voltages integration. A TOSCA 3-D model of the CMS magnet is developed to
describe the magnetic field everywhere outside the tracking volume measured
with the field-mapping machine. The results of the measurements and
calculations are presented, compared and discussed.Comment: 9 pages, 7 figures, 16 references, presented at the III International
Conference on Superconductivity and Magnetism (ICSM-2012), Kumburgaz,
Istanbul, Turkey, 29 April - 4 May 201
Measuring the Magnetic Flux Density with Flux Loops and Hall Probes in the CMS Magnet Flux Return Yoke
The Compact Muon Solenoid (CMS) is a general purpose detector, designed to
run at the highest luminosity at the CERN Large Hadron Collider (LHC). Its
distinctive features include a 4 T superconducting solenoid with 6-m-diameter
by 12.5-m-length free bore, enclosed inside a 10,000-ton return yoke made of
construction steel. The flux return yoke consists of five dodecagonal
three-layered barrel wheels and four end-cap disks at each end comprised of
steel blocks up to 620 mm thick, which serve as the absorber plates of the muon
detection system. To measure the field in and around the steel, a system of 22
flux loops and 82 3-D Hall sensors is installed on the return yoke blocks. A
TOSCA 3-D model of the CMS magnet is developed to describe the magnetic field
everywhere outside the tracking volume that was measured with the field-mapping
machine. The voltages induced in the flux loops by the magnetic flux changing
during the CMS magnet standard ramps down are measured with six 16-bit DAQ
modules. The off-line integration of the induced voltages reconstructs the
magnetic flux density in the yoke steel blocks at the operational magnet
current of 18.164 kA. The results of the flux loop measurements during three
magnet ramps down are presented and discussed.Comment: 3 pages, 6 figures, presented at the IEEE Nuclear Science Symposium
2016 (NSS) in Strasbourg, France on November 3, 2016. arXiv admin note: text
overlap with arXiv:1605.0877
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