38 research outputs found
Aiding clinicians through summarization of perinatal data
posterExploratory analysis has focused on developing summarized views of monitor-captured perinatal data to support adherence to established clinical protocols. In addition to facilitating rapid access to significant clinical trends and reducing subjective interpretation of monitor-captured data, combining data summaries with traditional monitor review may assist in the anticipation of complications
Force distributions in 3D granular assemblies: Effects of packing order and inter-particle friction
We present a systematic investigation of the distribution of normal forces at
the boundaries of static packings of spheres. A new method for the efficient
construction of large hexagonal-close-packed crystals is introduced and used to
study the effect of spatial ordering on the distribution of forces. Under
uniaxial compression we find that the form for the probability distribution of
normal forces between particles does not depend strongly on crystallinity or
inter-particle friction. In all cases the distribution decays exponentially at
large forces and shows a plateau or possibly a small peak near the average
force but does not tend to zero at small forces.Comment: 9 pages including 8 figure
Random Packings of Frictionless Particles
We study random packings of frictionless particles at T=0.
The packing fraction where the pressure becomes nonzero is the same as the
jamming threshold, where the static shear modulus becomes nonzero. The
distribution of threshold packing fractions narrows and its peak approaches
random close-packing as the system size increases. For packing fractions within
the peak, there is no self-averaging, leading to exponential decay of the
interparticle force distribution.Comment: 4 pages, 3 figure
Force distributions near the jamming and glass transitions
We calculate the distribution of interparticle normal forces near the
glass and jamming transitions in model supercooled liquids and foams,
respectively. develops a peak that appears near the glass or jamming
transitions, whose height increases with decreasing temperature, decreasing
shear stress and increasing packing density. A similar shape of was
observed in experiments on static granular packings. We propose that the
appearance of this peak signals the development of a yield stress. The
sensitivity of the peak to temperature, shear stress and density lends credence
to the recently proposed generalized jamming phase diagram.Comment: 4 pages, 3 postscript figures;Version 3 replaces figure 1 and removes
figure 2 from version 1. Significant rewording of version 1 to emphasize the
formation of peak in P(F) when these systems jam along five different routes
of the recently proposed jamming phase diagram. Version 2 displayed the
incorrect abstrac
LSST: from Science Drivers to Reference Design and Anticipated Data Products
(Abridged) We describe here the most ambitious survey currently planned in
the optical, the Large Synoptic Survey Telescope (LSST). A vast array of
science will be enabled by a single wide-deep-fast sky survey, and LSST will
have unique survey capability in the faint time domain. The LSST design is
driven by four main science themes: probing dark energy and dark matter, taking
an inventory of the Solar System, exploring the transient optical sky, and
mapping the Milky Way. LSST will be a wide-field ground-based system sited at
Cerro Pach\'{o}n in northern Chile. The telescope will have an 8.4 m (6.5 m
effective) primary mirror, a 9.6 deg field of view, and a 3.2 Gigapixel
camera. The standard observing sequence will consist of pairs of 15-second
exposures in a given field, with two such visits in each pointing in a given
night. With these repeats, the LSST system is capable of imaging about 10,000
square degrees of sky in a single filter in three nights. The typical 5
point-source depth in a single visit in will be (AB). The
project is in the construction phase and will begin regular survey operations
by 2022. The survey area will be contained within 30,000 deg with
, and will be imaged multiple times in six bands, ,
covering the wavelength range 320--1050 nm. About 90\% of the observing time
will be devoted to a deep-wide-fast survey mode which will uniformly observe a
18,000 deg region about 800 times (summed over all six bands) during the
anticipated 10 years of operations, and yield a coadded map to . The
remaining 10\% of the observing time will be allocated to projects such as a
Very Deep and Fast time domain survey. The goal is to make LSST data products,
including a relational database of about 32 trillion observations of 40 billion
objects, available to the public and scientists around the world.Comment: 57 pages, 32 color figures, version with high-resolution figures
available from https://www.lsst.org/overvie