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Is the World After All Just a Dream?
DocPerform is a multi and interdisciplinary research project based at City, University of London. Led by members of the Department of Library & Information Science, it comprises scholars and practitioners from the fields of performing arts and library & information science. The project concerns conceptual, methodological and technological innovations in the documentation of performance, and the extent to which performance may itself be considered to be a document. The collection of papers in this special issue of Proceedings from the Document Academy are selected from the second DocPerform Symposium, held at City, University of London, 6–7 November 2017. This editorial introduces those papers and provides disciplinary and historical context for DocPerform
A Large Eddy Simulation of Turbulent Compressible Convection: Differential Rotation in the Solar Convection Zone
We present results of two simulations of the convection zone, obtained by
solving the full hydrodynamic equations in a section of a spherical shell. The
first simulation has cylindrical rotation contours (parallel to the rotation
axis) and a strong meridional circulation, which traverses the entire depth.
The second simulation has isorotation contours about mid-way between cylinders
and cones, and a weak meridional circulation, concentrated in the uppermost
part of the shell.
We show that the solar differential rotation is directly related to a
latitudinal entropy gradient, which pervades into the deep layers of the
convection zone. We also offer an explanation of the angular velocity shear
found at low latitudes near the top. A non-zero correlation between radial and
zonal velocity fluctuations produces a significant Reynolds stress in that
region. This constitutes a net transport of angular momentum inwards, which
causes a slight modification of the overall structure of the differential
rotation near the top. In essence, the {\it thermodynamics controls the
dynamics through the Taylor-Proudman momentum balance}. The Reynolds stresses
only become significant in the surface layers, where they generate a weak
meridional circulation and an angular velocity `bump'.Comment: 11 pages, 14 figures, the first figure was too large and is excluded.
Accepted for publication in MNRA
Distribution of lactic acid between plasma and red cells during work and recovery
Lactic acid concentrations in plasma and red cells during work and recover
Surface coordinate measurement of rough diamonds
Imperial Users onl
Evaluation of a hybrid, anisotropic, multilayered, quadrilateral finite element
A multilayered finite element with bending-extensional coupling is evaluated for: (1) buckling of general laminated plates; (2) thermal stresses of laminated plates cured at elevated temperatures; (3) displacements of a bimetallic beam; and (4) displacement and stresses of a single-cell box beam with warped cover panels. Also, displacements and stresses for flat and spherical orthotropic and anisotropic segments are compared with results from higher order plate and shell finite-element analyses
Epitaxial gallium arsenide wafers
The preparation of GaAs epitaxial layers by a vapor transport process using AsCl3, Ga and H2 was pursued to provide epitaxial wafers suitable for the fabrication of transferred electron oscillators and amplifiers operating in the subcritical region. Both n-n(+) structures, and n(++)-n-n(+) sandwich structures were grown using n(+) (Si-doped) GaAs substrates. Process variables such as the input AsCl3 concentration, gallium temperature, and substrate temperature and temperature gradient and their effects on properties are presented and discussed
A cost-performance model for ground-based optical communications receiving telescopes
An analytical cost-performance model for a ground-based optical communications receiving telescope is presented. The model considers costs of existing telescopes as a function of diameter and field of view. This, coupled with communication performance as a function of receiver diameter and field of view, yields the appropriate telescope cost versus communication performance curve
Effects of Rotationally-Induced Mixing in Compact Binary Systems with Low-Mass Secondaries and in Single Solar-Type Stars
Many population synthesis and stellar evolution studies have addressed the
evolution of close binary systems in which the primary is a compact remnant and
the secondary is filling its Roche lobe, thus triggering mass transfer.
Although tidal locking is expected in such systems, most studies have neglected
the rotationally-induced mixing that may occur. Here we study the possible
effects of mixing in the mass-losing stars for a range in secondary star masses
and metallicities. We find that tidal locking can induce rotational mixing
prior to contact and thus affect the evolution of the secondary star if the
effects of the Spruit-Tayler dynamo are included both for angular momentum and
chemical transport. Once contact is made, the effect of mass transfer tends to
be more rapid than the evolutionary time scale, so the effects of mixing are no
longer directly important, but the mass transfer strips matter to inner layers
that may have been affected by the mixing. These effects are enhanced for
secondaries of 1-1.2 Msun and for lower metallicities. We discuss the possible
implications for the paucity of carbon in the secondaries of the cataclysmic
variable SS Cyg and the black hole candidate XTE J1118+480 and for the
progenitor evolution of Type Ia supernovae. We also address the issue of the
origin of blue straggler stars in globular and open clusters. We find that for
models that include rotation consistent with that observed for some blue
straggler stars, evolution is chemically homogeneous. This leads to tracks in
the HR diagram that are brighter and bluer than the non-rotating main-sequence
turn-off point. Rotational mixing could thus be one of the factors that
contribute to the formation of blue stragglers.Comment: 46 pages, 18 figure
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