3,556 research outputs found
Absorption spectrum of iron in the vacuum ultraviolet 2950 - 1588 angstrom
Absorption spectrum of iron in vacuum ultraviole
Environmental legislation as a driver of design
and other research output
Two-Particle Microrheology of quasi-2D Viscous Systems
We study the correlated motions of colloidal particles in a quasi-2D system
(Human Serum Albumin (HSA) protein molecules at an air-water interface) for
different surface viscosities . We observe a transition in the
behavior of the correlated motion, from 2-D interface dominated at high
to bulk fluid-dependent at low . The correlated motions
can be scaled onto a master curve which captures the features of this
transition. This master curve also characterizes the spatial dependence of the
flow field of a viscous interface in response to a force. From the flow field
and the correlated particle motions, we calculate a two-particle MSD (mean
square displacement) for direct comparison with rheological measurements.Comment: 4 pages, 4 figures, submitted to PR
Properties of cage rearrangements observed near the colloidal glass transition
We use confocal microscopy to study the motions of particles in concentrated
colloidal systems. Near the glass transition, diffusive motion is inhibited, as
particles spend time trapped in transient ``cages'' formed by neighboring
particles. We measure the cage sizes and lifetimes, which respectively shrink
and grow as the glass transition approaches. Cage rearrangements are more
prevalent in regions with lower local concentrations and higher disorder.
Neighboring rearranging particles typically move in parallel directions,
although a nontrivial fraction move in anti-parallel directions, usually from
pairs of particles with initial separations corresponding to the local maxima
and minima of the pair correlation function , respectively.Comment: 5 pages, 4 figures; text & figures revised in v
Hicks v. Dowd, Conservation Easements, and the Charitable Trust Doctrine: Setting the Record Straight
This is the fourth in an exchange of articles published by the Wyoming Law Review discussing the application of charitable trust principles to conservation easements conveyed as charitable gifts. In 2002, Johnson County, Wyoming, attempted to terminate a conservation easement that had been conveyed to the County as a tax-deductible charitable gift. The County\u27s actions were challenged, first in a suit brought by a resident of the County, Hicks v. Dowd, and then in a suit brought by the Wyoming Attorney General, Salzburg v. Dowd. The over six years of litigation associated with the easement\u27s attempted termination has been the catalyst and background for the exchange of articles
Hicks v. Dowd, Conservation Easements, and the Charitable Trust Doctrine: Setting the Record Straight
This is the fourth in an exchange of articles published by the Wyoming Law Review discussing the application of charitable trust principles to conservation easements conveyed as charitable gifts. In 2002, Johnson County, Wyoming, attempted to terminate a conservation easement that had been conveyed to the County as a tax-deductible charitable gift. The County\u27s actions were challenged, first in a suit brought by a resident of the County, Hicks v. Dowd, and then in a suit brought by the Wyoming Attorney General, Salzburg v. Dowd. The over six years of litigation associated with the easement\u27s attempted termination has been the catalyst and background for the exchange of articles
Circles in the Sky: Finding Topology with the Microwave Background Radiation
If the universe is finite and smaller than the distance to the surface of
last scatter, then the signature of the topology of the universe is writ large
on the microwave background sky. We show that the microwave background will be
identified at the intersections of the surface of last scattering as seen by
different ``copies'' of the observer. Since the surface of last scattering is a
two-sphere, these intersections will be circles, regardless of the background
geometry or topology. We therefore propose a statistic that is sensitive to all
small, locally homogeneous topologies. Here, small means that the distance to
the surface of last scatter is smaller than the ``topology scale'' of the
universe.Comment: 14 pages, 10 figures, IOP format. This paper is a direct descendant
of gr-qc/9602039. To appear in a special proceedings issue of Class. Quant.
Grav. covering the Cleveland Topology & Cosmology Worksho
Attraction Between Like-Charged Walls: Short-Ranged Simulations Using Local Molecular Field Theory
Effective attraction between like-charged walls mediated by counterions is
studied using local molecular field (LMF) theory. Monte Carlo simulations of
the "mimic system'' given by LMF theory, with short-ranged "Coulomb core"
interactions in an effective single particle potential incorporating a
mean-field average of the long-ranged Coulomb interactions, provide a direct
test of the theory, and are in excellent agreement with more complex
simulations of the full Coulomb system by Moreira and Netz [Eur. Phys. J. E 8,
33 (2002)]. A simple, generally-applicable criterion to determine the
consistency parameter sigma_{min} needed for accurate use of the LMF theory is
presented
Direct visualization of aging in colloidal glasses
We use confocal microscopy to directly visualize the dynamics of aging
colloidal glasses. We prepare a colloidal suspension at high density, a simple
model system which shares many properties with other glasses, and initiate
experiments by stirring the sample. We follow the motion of several thousand
colloidal particles after the stirring and observe that their motion
significantly slows as the sample ages. The aging is both spatially and
temporally heterogeneous. Furthermore, while the characteristic relaxation time
scale grows with the age of the sample, nontrivial particle motions continue to
occur on all time scales.Comment: submitted to proceedings for Liquid Matter Conference 200
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