15,109 research outputs found
Think Locally, Act Locally: Spillovers, Spillbacks, and Efficient Decentralized Policymaking
In this paper, we analyze a class of models in which there are interjurisdictional spillovers among heterogeneous jurisdictions, as illustrated for instance by CO2 emissions that affect the global environment. Each jurisdiction’s emissions depend upon the local stock of private capital. Capital is interjurisdictionally-mobile and may be taxed to help finance local public expenditures. We show that decentralized policymaking leads to efficient resource allocations in important cases, even in the complete absence of corrective interventions by higher-level governments or coordination of policy through Coasian bargaining. In particular, even when the preferences and production technologies differ among the agents, the decentralized system can still result in globally efficient allocation.
Point defect concentrations in metastable Fe-C alloys
Point defect species and concentrations in metastable Fe-C alloys are
determined using density functional theory and a constrained free-energy
functional. Carbon interstitials dominate unless iron vacancies are in
significant excess, whereas excess carbon causes greatly enhances vacancy
concentration. Our predictions are amenable to experimental verification; they
provide a baseline for rationalizing complex microstructures known in hardened
and tempered steels, and by extension other technological materials created by
or subjected to extreme environments
Hypothesis testing for Gaussian states on bosonic lattices
The asymptotic state discrimination problem with simple hypotheses is
considered for a cubic lattice of bosons. A complete solution is provided for
the problems of the Chernoff and the Hoeffding bounds and Stein's lemma in the
case when both hypotheses are gauge-invariant Gaussian states with
translation-invariant quasi-free parts.Comment: 22 pages, submitted versio
Improved Formalism for Precision Higgs Coupling Fits
Future e+e- colliders give the promise of model-independent determinations of
the couplings of the Higgs boson. In this paper, we present an improved
formalism for extracting Higgs boson couplings from e+e- data, based on the
Effective Field Theory description of corrections to the Standard Model. We
apply this formalism to give projections of Higgs coupling accuracies for
stages of the International Linear Collider and for other proposed e+e-
colliders.Comment: 34 pages, 4 figures; v4: clarifications and new references added; v5,
additional references adde
Polymers in Curved Boxes
We apply results derived in other contexts for the spectrum of the Laplace
operator in curved geometries to the study of an ideal polymer chain confined
to a spherical annulus in arbitrary space dimension D and conclude that the
free energy compared to its value for an uncurved box of the same thickness and
volume, is lower when , stays the same when , and is higher when
\mbox{}. Thus confining an ideal polymer chain to a cylindrical shell,
lowers the effective bending elasticity of the walls, and might induce
spontaneous symmetry breaking, i.e. bending. (Actually, the above mentioned
results show that {\em {any}} shell in induces this effect, except for
a spherical shell). We compute the contribution of this effect to the bending
rigidities in the Helfrich free energy expression.Comment: 20 pages RevTeX, epsf; 4 figures; submitted to Macromoledule
Spontaneous thermal runaway as an ultimate failure mechanism of materials
The first theoretical estimate of the shear strength of a perfect crystal was
given by Frenkel [Z. Phys. 37, 572 (1926)]. He assumed that as slip occurred,
two rigid atomic rows in the crystal would move over each other along a slip
plane. Based on this simple model, Frenkel derived the ultimate shear strength
to be about one tenth of the shear modulus. Here we present a theoretical study
showing that catastrophic material failure may occur below Frenkel's ultimate
limit as a result of thermal runaway. We demonstrate that the condition for
thermal runaway to occur is controlled by only two dimensionless variables and,
based on the thermal runaway failure mechanism, we calculate the maximum shear
strength of viscoelastic materials. Moreover, during the thermal
runaway process, the magnitude of strain and temperature progressively localize
in space producing a narrow region of highly deformed material, i.e. a shear
band. We then demonstrate the relevance of this new concept for material
failure known to occur at scales ranging from nanometers to kilometers.Comment: 4 pages, 3 figures. Eq. (6) and Fig. 2a corrected; added references;
improved quality of figure
PIV measurement of internal flow in mini centrifugal pump
The diameter of the ventricular assist pump and cooling pump for electrical devices like servers is about a dozen millimetres and these kinds of pumps belong to the mini pump. The internal flow condition of the mini centrifugal pump has to be clarified because there are so many types of mini pumps according to special specifications and shapes. Therefore, in this research, an open impeller was adopted as a mini centrifugal pump with 55mm impeller diameter in consideration of reduction in impeller manufacturing cost and its internal flow was investigated. Since the outlet angle of the test impeller is large, the maximum efficiency flow rate moves to a large flow rate and the relatively high head and efficiency were obtained in large flow rate region. In the present paper, the velocity and vorticity distribution near the volute tongue are shown and the internal flow in the mini centrifugal pump is clarified based on the PIV measurement results
Locating Principals Who are Leaders: The Assessment Center Concept
With knowledge about leadership, the selection of leaders can be improved
On the definition of Quantum Free Particle on Curved Manifolds
A selfconsistent definition of quantum free particle on a generic curved
manifold emerges naturally by restricting the dynamics to submanifolds of
co-dimension one.
PACS 0365 0240Comment: 8 p., phyzzx macropackag
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