13,026 research outputs found
Emerging urban markets in the Midwest
Chicago (Ill.) ; Community development ; Middle West
Multiscale model of global inner-core anisotropy induced by hcp-alloy plasticity
Multiscale model of inner-core anisotropy produced by hcp alloy
deformation 5 to 20% single-crystal elastic anisotropy and plastic
deformation by pyramidal slip Low-degree inner-core formation model
with faster crystallization at the equatorThe Earth's solid inner-core exhibits
a global seismic anisotropy of several percents. It results from a coherent
alignment of anisotropic Fe-alloy crystals through the inner-core history that
can be sampled by present-day seismic observations. By combining
self-consistent polycrystal plasticity, inner-core formation models,
Monte-Carlo search for elastic moduli, and simulations of seismic measurements,
we introduce a multiscale model that can reproduce a global seismic anisotropy
of several percents aligned with the Earth's rotation axis. Conditions for a
successful model are an hexagonal-close-packed structure for the inner-core
Fe-alloy, plastic deformation by pyramidal \textless{}c+a\textgreater{} slip,
and large-scale flow induced by a low-degree inner-core formation model. For
global anisotropies ranging between 1 and 3%, the elastic anisotropy in the
single crystal ranges from 5 to 20% with larger velocities along the c-axis
Electric field distortions in structures of the twist bend nematic (NTB) phase of a bent-core liquid crystal
Dielectric spectroscopy of a twist bend nematic phase of an achiral bent core
liquid crystalline compound under DC bias is used to investigate its response
to electric field. Two collective relaxation processes are revealed, these are
assigned to distortions of helicoidal structure by the external bias field.
Frequency of the mode depends primarily on the helicoidal angle and has
anomalous, softening- like behaviour at the nematic to the twist bend nematic
transition. A coupling of dielectric anisotropy with electric field gives rise
to a new equilibrium periodic structure in the time scale involved. The modulus
of the wave vector gradually vanishes on increasing the bias field (except for
the initial behaviour, which is just the opposite). Transition from the twist
bend to the splay bend structure is clearly observed by a sudden drop in the
frequency of this mode, which decreases almost linearly with increasing field.
Results agree with predictions from current models for the periodically
distorted a twist bend nematic phase.Comment: 14 PAGES, 7 FIGURES, submitted to Physical Review Letter
The binational Great Lakes economy
Great Lakes ; North American Free Trade Agreement ; Canada ; Manufactures
From Bare Metal to Virtual: Lessons Learned when a Supercomputing Institute Deploys its First Cloud
As primary provider for research computing services at the University of
Minnesota, the Minnesota Supercomputing Institute (MSI) has long been
responsible for serving the needs of a user-base numbering in the thousands.
In recent years, MSI---like many other HPC centers---has observed a growing
need for self-service, on-demand, data-intensive research, as well as the
emergence of many new controlled-access datasets for research purposes. In
light of this, MSI constructed a new on-premise cloud service, named Stratus,
which is architected from the ground up to easily satisfy data-use agreements
and fill four gaps left by traditional HPC. The resulting OpenStack cloud,
constructed from HPC-specific compute nodes and backed by Ceph storage, is
designed to fully comply with controls set forth by the NIH Genomic Data
Sharing Policy.
Herein, we present twelve lessons learned during the ambitious sprint to take
Stratus from inception and into production in less than 18 months. Important,
and often overlooked, components of this timeline included the development of
new leadership roles, staff and user training, and user support documentation.
Along the way, the lessons learned extended well beyond the technical
challenges often associated with acquiring, configuring, and maintaining
large-scale systems.Comment: 8 pages, 5 figures, PEARC '18: Practice and Experience in Advanced
Research Computing, July 22--26, 2018, Pittsburgh, PA, US
Generation and detection of NOON states in superconducting circuits
NOON states, states between two modes of light of the form
allow for super-resolution interformetry. We
show how NOON states can be efficiently produced in circuit quntum
electrodynamics using superconducting phase qubits and resonators. We propose a
protocol where only one interaction between the two modes is required, creating
all the necessary entanglement at the start of the procedure. This protocol
makes active use of the first three states of the phase qubits. Additionally,
we show how to efficiently verify the success of such an experiment, even for
large NOON states, using randomly sampled measurements and semidefinite
programming techniques.Comment: 15 pages and 3 figure
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