17,843 research outputs found
Key Findings From HSC's 2010 Site Visits: Health Care Markets Weather Economic Downturn, Brace for Health Reform
Presents findings about hospital payment rate increases, hospital-physician alignment, and insurance premiums, funding for safety-net providers, and their implications from HSC's site visits to twelve nationally representative metropolitan communities
String order and hidden topological symmetry in the SO(2n+1) symmetric matrix product states
We have introduced a class of exactly soluble Hamiltonian with either
SO(2n+1) or SU(2) symmetry, whose ground states are the SO(2n+1) symmetric
matrix product states. The hidden topological order in these states can be
fully identified and characterized by a set of nonlocal string order
parameters. The Hamiltonian possesses a hidden
topological symmetry. The breaking of this hidden symmetry leads to
degenerate ground states with disentangled edge states in an open chain system.
Such matrix product states can be regarded as cluster states, applicable to
measurement-based quantum computation.Comment: 5 pages, 1 figur
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Analysis of rolling bearing power loss models for twin screw oil injected compressor
The mechanical losses inside a screw compressor limit the performance of the compressor in terms of efficiency. These losses arise due to relative motion between elements inside the screw compressor. The estimation of mechanical losses predicted in the literature is around 10-15% of the total shaft power. One of the elements which contribute significantly to these losses is rolling element bearings. There are numerous mathematical models available which predict power losses in the rolling bearings. The objective of this paper is to study different models to predict power loss for rolling bearings and to predict the power losses for the bearings used for oil injected, twin screw compressor. A comparison between different power loss models for different operating conditions of compressor is also presented in this paper and results of analysis are compared with available experimental observations. The analysis helps to determine suitable power loss model for different operating conditions and more realistic predictions of the power losses. This allows designers for more accurate estimation of the performance of screw compressors
2D and 3D cubic monocrystalline and polycrystalline materials: their stability and mechanical properties
We consider 2- and 3-dimensional cubic monocrystalline and polycrystalline
materials. Expressions for Young's and shear moduli and Poisson's ratio are
expressed in terms of eigenvalues of the stiffness tensor. Such a form is well
suited for studying properties of these mechanical characteristics on sides of
the stability triangles. For crystalline high-symmetry directions lines of
vanishing Poisson's ratio are found. These lines demarcate regions of the
stability triangle into areas of various auxeticity properties. The simplest
model of polycrystalline 2D and 3D cubic materials is considered. In
polycrystalline phases the region of complete auxetics is larger than for
monocrystalline materials.Comment: 9 pages, 3 figures, in proceedings of the Tenth International School
on Theoretical Physics, Symmetry and Structural Properties of Condensed
Matter, Myczkowce 200
Healthcare Price Transparency: Policy Approaches and Estimated Impacts on Spending
Healthcare price transparency discussions typically focus on increasing patients' access to information about their out-of-pocket costs, but that focus is too narrow and should include other audiences -- physicians, employers, health plans and policymakers -- each with distinct needs and uses for healthcare price information. Greater price transparency can reduce U.S. healthcare spending.For example, an estimated 18 billion over the next decade. While 40 trillionin total projected health spending over the same period. In contrast, using state all-payer claims databases to gather and report hospital-specific prices might reduce spending by an estimated $61 billion over 10 years.The effects of price transparency depend critically on the intended audience, the decision-making context and how prices are presented. And the impact of price transparency can be greatly amplified if target audiences are able and motivated to act on the information. Simply providing prices is insufficient to control spending without other shifts in healthcare financing, including changes in benefit design to make patients more sensitive to price differences among providers and alternative treatments. Other reforms that can amplify the impact of price transparency include shifting from fee-for-service payments that reward providers for volume to payment methods that put providers at risk for spending for episodes of care or defined patient populations. While price transparency alone seems unlikely to transform the healthcare system, it can play a needed role in enabling effective reforms in value-based benefit design and provider payment
Bounds of Efficiency at Maximum Power for Normal-, Sub- and Super-Dissipative Carnot-Like Heat Engines
The Carnot-like heat engines are classified into three types (normal-, sub-
and super-dissipative) according to relations between the minimum irreversible
entropy production in the "isothermal" processes and the time for completing
those processes. The efficiencies at maximum power of normal-, sub- and
super-dissipative Carnot-like heat engines are proved to be bounded between
and , and , 0 and
, respectively. These bounds are also shared by linear, sub-
and super-linear irreversible Carnot-like engines [Tu and Wang, Europhys. Lett.
98, 40001 (2012)] although the dissipative engines and the irreversible ones
are inequivalent to each other.Comment: 1 figur
Thermoelectric efficiency at maximum power in a quantum dot
We identify the operational conditions for maximum power of a
nanothermoelectric engine consisting of a single quantum level embedded between
two leads at different temperatures and chemical potentials. The corresponding
thermodynamic efficiency agrees with the Curzon-Ahlborn expression up to
quadratic terms in the gradients, supporting the thesis of universality beyond
linear response.Comment: 4 pages, 3 figure
Ultra narrow AuPd and Al wires
In this letter we discuss a novel and versatile template technique aimed to
the fabrication of sub-10 nm wide wires. Using this technique, we have
successfully measured AuPd wires, 12 nm wide and as long as 20 m. Even
materials that form a strong superficial oxide, and thus not suited to be used
in combination with other techniques, can be successfully employed. In
particular we have measured Al wires, with lateral width smaller or comparable
to 10 nm, and length exceeding 10 m.Comment: 4 pages, 4 figures. Pubblished in APL 86, 172501 (2005). Added
erratum and revised Fig.
Multiple-Resampling Receiver Design for OFDM Over Doppler-Distorted Underwater Acoustic Channels
Cataloged from PDF version of article.In this paper, we focus on orthogonal frequency-divisionmultiplexing
(OFDM) receiver designs for underwater acoustic
(UWA) channels with user- and/or path-specific Doppler scaling
distortions. The scenario is motivated by the cooperative communications
framework, where distributed transmitter/receiver
pairs may experience significantly different Doppler distortions, as
well as by the single-user scenarios, where distinct Doppler scaling
factors may exist among different propagation paths. The conventional
approach of front–end resampling that corrects for common
Doppler scalingmay not be appropriatein such scenarios, rendering
a post-fast-Fourier-transform (FFT) signal that is contaminated by
user- and/or path-specific intercarrier interference. To counteract
this problem, we propose a family of front–end receiver structures
thatutilizemultiple-resampling (MR)branches,eachmatched to the
Doppler scaling factor of a particular user and/or path. Following
resampling, FFT modules transform the Doppler-compensated
signals into the frequency domain for further processing through
linear or nonlinear detection schemes. As part of the overall receiver
structure, a gradient–descent approachis also proposed to refine the
channel estimates obtained by standard sparse channel estimators.
The effectiveness and robustness of the proposed receivers are
demonstrated via simulations, as well as emulations based on real
data collected during the 2010 Mobile Acoustic Communications
Experiment (MACE10, Martha’s Vineyard, MA) and the 2008
Kauai Acomms MURI (KAM08, Kauai, HI) experiment
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