21,321 research outputs found
Explosive condensation in a mass transport model
We study a far-from-equilibrium system of interacting particles, hopping
between sites of a 1d lattice with a rate which increases with the number of
particles at interacting sites. We find that clusters of particles, which
initially spontaneously form in the system, begin to move at increasing speed
as they gain particles. Ultimately, they produce a moving condensate which
comprises a finite fraction of the mass in the system. We show that, in
contrast with previously studied models of condensation, the relaxation time to
steady state decreases as an inverse power of ln L with system size L and that
condensation is instantenous for L-->infinity.Comment: 5 pages, 5 figures, minor changes, references adde
Welding of precipitation-hardening stainless steels
Welding of precipitation hardening stainless steel
The effect of neuronal conditional knock-out of peroxisome proliferator-activated receptors in the MPTP mouse model of Parkinson's disease
This study was supported by Parkinson’s Disease Foundation (IRGP 09-11 (P.T.)), the Royal Society (2006/R1 (P.T.)), the Wellcome Trust (WT080782MF (P.T.)), the Biotechnology and Biological Sciences Research Council (P.T. and H.L.M.), the National Institutes of Health (DK057978) (R.M.E.), and by grants from the Leona M. and Harry B. Helmsley Charitable Trust (R.M.E.), the Glenn Foundation for Medical Research (R.M.E.), and the Ellison Medical Foundation (R.M.E.). R.M.E. is an investigator at the Howard Hughes Medical Institute and March of Dimes Chair in Molecular and Developmental Biology at the Salk Institute. The authors would like to thank Lynne J. Hocking, University of Aberdeen, for her assistance with the statistics. We are grateful to the staff of the Medical Research Facility for their help with the animal care and the microscopy core facility at the University of Aberdeen for the use of microscopy equipment.Peer reviewedPublisher PD
The effects of polydispersity and metastability on crystal growth kinetics
We investigate the effect of metastable gas-liquid (G-L) separation on
crystal growth in a system of either monodisperse or slightly size-polydisperse
square well particles, using a simulation setup that allows us to focus on the
growth of a single crystal. Our system parameters are such that, inside the
metastable G-L binodal, a macroscopic layer of the gas phase "coats" the
crystal as it grows, consistent with experiment and theoretical free energy
considerations. Crucially, the effect of this metastable G-L separation on the
crystal growth rate depends qualitatively on whether the system is
polydisperse. We measure reduced polydispersity and qualitatively different
local size ordering in the crystal relative to the fluid, proposing that the
required fractionation is dynamically facilitated by the gas layer. Our results
show that polydispersity and metastability, both ubiquitous in soft matter,
must be considered in tandem if their dynamical effects are to be understood.Comment: Published in Soft Matter. DOI: 10.1039/C3SM27627
Driven Tracers in a One-Dimensional Periodic Hard-Core Lattice Gas
Totally asymmetric tracer particles in an environment of symmetric hard-core
particles on a ring are studied. Stationary state properties, including the
environment density profile and tracer velocity are derived explicitly for a
single tracer. Systems with more than one tracer are shown to factorise into
single-tracer subsystems, allowing the single tracer results to be extended to
an arbitrary number of tracers. We demonstrate the existence of a cooperative
effect, where many tracers move with a higher velocity than a single tracer in
an environment of the same size and density. Analytic calculations are verified
by simulations. Results are compared to established results in related systems.Comment: Added reference. Corrected typo in section 3.
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