1,055 research outputs found
Fluctuations and Intrinsic Pinning in Layered Superconductors
A flux liquid can condense into a smectic crystal in a pure layered
superconductors with the magnetic field oriented nearly parallel to the layers.
If the smectic order is commensurate with the layering, this crystal is {\sl
stable} to point disorder. By tilting and adjusting the magnitude of the
applied field, both incommensurate and tilted smectic and crystalline phases
are found. We discuss transport near the second order smectic freezing
transition, and show that permeation modes lead to a small non--zero
resistivity and large but finite tilt modulus in the smectic crystal.Comment: 4 pages + 1 style file + 1 figure (as uufile) appended, REVTEX 3.
Implementing an offsite construction strategy: a UK contracting organisation case study
Many United Kingdom (UK) contractors only consider offering offsite solutions on a
bespoke project-by-project basis, with very few having immediate plans for
integrating fully offsite manufacturing as part of their core business strategy. Limited
literature exists regarding how a major UK contractor could achieve such a strategic
offsite capability, as this capability is usually referred to as an out-sourced, subcontracted
activity. The concept of a major contractor providing its own capability
and completing large scale infrastructure projects using offsite construction (OSC)
methods is not common in the UK, although the concept is less rare in certain other
countries, such as Australia. The aim of this paper is to determine the benefits that
OSC can offer for UK contractors and to investigate how an offsite strategy can be
implemented in practice. Semi-structured interviews were conducted with a major UK
contractor, transcribed, and thematically analysed to determine how effectively the
offsite strategy and methods were being implemented at different levels within the
contractor’s operations. The potential attractiveness and future of offsite for major
UK contractors is discussed. The paper concludes with three recommendations for
contractors considering the development of offsite capability. First, commitment from
senior leadership at a strategic level, second, clear communication to all level through
the firm and third, investment in innovation
Topological Defects on Fluctuating Surfaces: General Properties and the Kosterlitz-Thouless Transition
We investigate the Kosterlitz-Thouless transition for hexatic order on a free
fluctuating membrane and derive both a Coulomb gas and a sine-Gordon
Hamiltonian to describe it. The Coulomb-gas Hamiltonian includes charge
densities arising from disclinations and from Gaussian curvature. There is an
interaction coupling the difference between these two densities, whose strength
is determined by the hexatic rigidity, and an interaction coupling Gaussian
curvature densities arising from the Liouville Hamiltonian resulting from the
imposition of a covariant cutoff. In the sine-Gordon Hamiltonian, there is a
linear coupling between a scalar field and the Gaussian curvature. We discuss
gauge-invariant correlation function for hexatic order and the dielectric
constant of the Coulomb gas. We also derive renormalization group recursion
relations that predict a transition with decreasing bending rigidity .Comment: REVTEX, 45 pages with 11 postscript figures compressed using uufiles.
Accepted for publication in Phys. Rev.
Recommended from our members
Book review of perspectives on organizational fit by Cheri Ostroff and Timothy A. Judge (Editors)
From the first moment you set your eyes on this book, you are aware
that it is a serious endeavor. Edited by two of the most published people in the field and sporting an imposing black and lime green dust cover containing an image of a swarm of black skull-headed moths, it contains chapters written by virtually all of “the good and the great” of the field. A flick through the pages reveals hundreds of pages of narrow margins and dense typescript interspersed with equations and three-dimensional graphs. This is a book that demands attention
Book review of 'the people make the place: dynamic linkages between individuals and organizations edited by D. Brent Smith'
The People Make the Place is a festschrift celebrating the work of industrial/organizational psychologist Benjamin Schneider. It contains 11 specially written chapters each addressing a different element of Schneider’s work. The twelfth chapter, written by the honored scholar, summarizes the contributions and uses the opportunity to clarify many of the ideas surrounding attraction-selection-attrition (ASA) theory
Current Status of Simulations
As the title suggests, the purpose of this chapter is to review the current
status of numerical simulations of black hole accretion disks. This chapter
focuses exclusively on global simulations of the accretion process within a few
tens of gravitational radii of the black hole. Most of the simulations
discussed are performed using general relativistic magnetohydrodynamic (MHD)
schemes, although some mention is made of Newtonian radiation MHD simulations
and smoothed particle hydrodynamics. The goal is to convey some of the exciting
work that has been going on in the past few years and provide some speculation
on future directions.Comment: 15 pages, 14 figures, to appear in the proceedings of the ISSI-Bern
workshop on "The Physics of Accretion onto Black Holes" (8-12 October 2012
Hydrodynamics of Spatially Ordered Superfluids
We derive the hydrodynamic equations for the supersolid and superhexatic
phases of a neutral two-dimensional Bose fluid. We find, assuming that the
normal part of the fluid is clamped to an underlying substrate, that both
phases can sustain third-sound modes and that in the supersolid phase there are
additional modes due to the superfluid motion of point defects (vacancies and
interstitials).Comment: 24 pages of ReVTeX and 7 uuencoded figures. Submitted for publication
in Phys. Rev.
Interstitials, Vacancies and Dislocations in Flux-Line Lattices: A Theory of Vortex Crystals, Supersolids and Liquids
We study a three dimensional Abrikosov vortex lattice in the presence of an
equilibrium concentration of vacancy, interstitial and dislocation loops.
Vacancies and interstitials renormalize the long-wavelength bulk and tilt
elastic moduli. Dislocation loops lead to the vanishing of the long-wavelength
shear modulus. The coupling to vacancies and interstitials - which are always
present in the liquid state - allows dislocations to relax stresses by climbing
out of their glide plane. Surprisingly, this mechanism does not yield any
further independent renormalization of the tilt and compressional moduli at
long wavelengths. The long wavelength properties of the resulting state are
formally identical to that of the ``flux-line hexatic'' that is a candidate
``normal'' hexatically ordered vortex liquid state.Comment: 21 RevTeX pgs, 7 eps figures uuencoded; corrected typos, published
versio
Calibration of Tethered Particle Motion Experiments
The Tethered Particle Motion (TPM) method has been used to observe and characterize a variety of protein-DNA interactions including DNA loping and transcription. TPM experiments exploit the Brownian motion of a DNA-tethered bead to probe biologically relevant conformational changes of the tether. In these experiments, a change in the extent of the bead’s random motion is used as a reporter of the underlying macromolecular dynamics and is often deemed sufficient for TPM analysis. However, a complete understanding of how the motion depends on the physical properties of the tethered particle complex would permit more quantitative and accurate evaluation of TPM data. For instance, such understanding can help extract details about a looped complex geometry (or multiple coexisting geometries) from TPM data. To better characterize the measurement capabilities of TPM experiments involving DNA tethers, we have carried out a detailed calibration of TPM magnitude as a function of DNA length and particle size. We also explore how experimental parameters such as acquisition time and exposure time affect the apparent motion of the tethered particle. We vary the DNA length from 200 bp to 2.6 kbp and consider particle diameters of 200, 490 and 970 nm. We also present a systematic comparison between measured particle excursions and theoretical expectations, which helps clarify both the experiments and models of DNA conformation
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