4,579 research outputs found
Energy absorption device Patent
Energy absorption device in high precision gear train for protection against damage to components caused by stop load
Orientations of the lamellar phase of block copolymer melts under oscillatory shear flow
We develop a theory to describe the reorientation phenomena in the lamellar
phase of block copolymer melt under reciprocating shear flow. We show that
similar to the steady-shear, the oscillating flow anisotropically suppresses
fluctuations and gives rise to the parallel-perpendicular orientation
transition. The experimentally observed high-frequency reverse transition is
explained in terms of interaction between the melt and the shear-cell walls.Comment: RevTex, 3 pages, 1 figure, submitted to PR
The effect of shear on persistence in coarsening systems
We analytically study the effect of a uniform shear flow on the persistence
properties of coarsening systems. The study is carried out within the
anisotropic Ohta-Jasnow-Kawasaki (OJK) approximation for a system with
nonconserved scalar order parameter. We find that the persistence exponent
theta has a non-trivial value: theta = 0.5034... in space dimension d=3, and
theta = 0.2406... for d=2, the latter being exactly twice the value found for
the unsheared system in d=1. We also find that the autocorrelation exponent
lambda is affected by shear in d=3 but not in d=2.Comment: 6 page
Recommended from our members
Analysis of teacher non-verbal behavior and student perceptions of that behavior in a high school typewriting classroom.
Orientational phase transitions in the hexagonal phase of a diblock copolymer melt under shear flow
We generalize the earlier theory by Fredrickson [J. Rheol. v.38, 1045 (1994)]
to study the orientational behaviour of the hexagonal phase of diblock
copolymer melt subjected to steady shear flow. We use symmetry arguments to
show that the orientational ordering in the hexagonal phase is a much weaker
effect than in the lamellae. We predict the parallel orientation to be stable
at low and the perpendicular orientation at high shear rates. Our analysis
reproduces the experimental results by Tepe et al. [Macromolecules v.28, 3008
(1995)] and explains the difficulties in experimental observation of the
different orientations in the hexagonal phase.Comment: 21 pages, 6 eps figures, submitted to Physical Review
Bulletin No. 350 - Cemeteries of Box Elder and Summit Counties
One of man\u27s greatest challenges is to build institutions that adequately meet basic needs. A cemetery is a social institution invented to take care of needs related to the dead.
Times and conditions change. A design which seemed adequate when initiated may soon become archaic and out-moded if it is not modified in the light of new discoveries.
This study raises many issues about cemeteries. As one reads the bulletin many questions concerning the nature and function of other institutions arise. What is their condition in contrast with the cemeteries?
This publication, the first in an institution series planned by the authors, suggests that the cemeteries when measured by reasonable standards appear to be sub-standard in many places. What functions in addition to burial should cemeteries perform? Under what conditions can cemeteries have greater significance and meaning to the people? This study is an appraisal of one institution. Can cemeteries or other institutions be effective if they are not subjected to regular appraisal
Derivation of an Abelian effective model for instanton chains in 3D Yang-Mills theory
In this work, we derive a recently proposed Abelian model to describe the
interaction of correlated monopoles, center vortices, and dual fields in three
dimensional SU(2) Yang-Mills theory. Following recent polymer techniques,
special care is taken to obtain the end-to-end probability for a single
interacting center vortex, which constitutes a key ingredient to represent the
ensemble integration.Comment: 18 pages, LaTe
Facilitated spin models: recent and new results
Facilitated or kinetically constrained spin models (KCSM) are a class of
interacting particle systems reversible w.r.t. to a simple product measure.
Each dynamical variable (spin) is re-sampled from its equilibrium distribution
only if the surrounding configuration fulfills a simple local constraint which
\emph{does not involve} the chosen variable itself. Such simple models are
quite popular in the glass community since they display some of the peculiar
features of glassy dynamics, in particular they can undergo a dynamical arrest
reminiscent of the liquid/glass transitiom. Due to the fact that the jumps
rates of the Markov process can be zero, the whole analysis of the long time
behavior becomes quite delicate and, until recently, KCSM have escaped a
rigorous analysis with the notable exception of the East model. In these notes
we will mainly review several recent mathematical results which, besides being
applicable to a wide class of KCSM, have contributed to settle some debated
questions arising in numerical simulations made by physicists. We will also
provide some interesting new extensions. In particular we will show how to deal
with interacting models reversible w.r.t. to a high temperature Gibbs measure
and we will provide a detailed analysis of the so called one spin facilitated
model on a general connected graph.Comment: 30 pages, 3 figure
Evidence of a Critical time in Constrained Kinetic Ising models
We study the relaxational dynamics of the one-spin facilitated Ising model
introduced by Fredrickson and Andersen. We show the existence of a critical
time which separates an initial regime in which the relaxation is exponentially
fast and aging is absent from a regime in which relaxation becomes slow and
aging effects are present. The presence of this fast exponential process and
its associated critical time is in agreement with some recent experimental
results on fragile glasses.Comment: 20 Pages + 7 Figures, Revte
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