8,055 research outputs found
Spectral imbalance and the normalized dissipation rate of turbulence
The normalized turbulent dissipation rate is studied in decaying
and forced turbulence by direct numerical simulations, large-eddy simulations,
and closure calculations. A large difference in the values of is
observed for the two types of turbulence. This difference is found at moderate
Reynolds number, and it is shown that it persists at high Reynolds number,
where the value of becomes independent of the Reynolds number, but
is still not unique. This difference can be explained by the influence of the
nonlinear cascade time that introduces a spectral disequilibrium for
statistically nonstationary turbulence. Phenomenological analysis yields simple
analytical models that satisfactorily reproduce the numerical results. These
simple spectral models also reproduce and explain the increase of
at low Reynolds number that is observed in the simulations
Decuplet baryon magnetic moments in a QCD-based quark model beyond quenched approximation
We study the decuplet baryon magnetic moments in a QCD-based quark model
beyond quenched approximation. Our approach for unquenching the theory is based
on the heavy baryon perturbation theory in which the axial couplings for baryon
- meson and the meson-meson-photon couplings from the chiral perturbation
theory are used together with the QM moment couplings. It also involves the
introduction of a form factor characterizing the structure of baryons
considered as composite particles. Using the parameters obtained from fitting
the octet baryon magnetic moments, we predict the decuplet baryon magnetic
moments. The magnetic moment is found to be in good agreement with
experiment: is predicted to be compared to the
experimental result of (2.02 0.05) .Comment: 19 pages, 2 figure
Valence bond glass on an fcc lattice in the double perovskite Ba2YMoO6
Peer reviewedPublisher PD
Broilers with Taste - Sustainable chicken takes flight
Engelse versie van de brochure 'Pluimvee met smaak : duurzame kip krijgt vleugels', die laat zien waar kansen liggen voor de Nederlandse pluimveesector om te verduurzamen. Twee uiteenlopende concepten, de Som der Delen en de Windstreek, geven ieder op eigen wijze invulling aan duurzaamheid op het primaire bedrijf. Ze bevatten belangrijke elementen voor verduurzaming, die als geheel of in onderdelen, nu of later, in de praktijk gebracht kunnen worden. Duurzaamheid kent immers niet één, maar vele vormen, afhankelijk van de ondernemers, de markt en de omgeving
Ferromagnetism below 10 K in Mn doped BiTe
Ferromagnetism is observed below 10 K in [Bi0.75Te0.125Mn0.125]Te. This
material has the BiTe structure, which is made from the stacking of two
Te-Bi-Te-Bi-Te blocks and one Bi-Bi block per unit cell. Crystal structure
analysis shows that Mn is localized in the Bi2 blocks, and is accompanied by an
equal amount of TeBi anti-site occupancy in the Bi2Te3 blocks. These TeBi
anti-site defects greatly enhance the Mn solubility. This is demonstrated by
comparison of the [Bi1-xMnx]Te and [Bi1-2xTexMnx]Te series; in the former, the
solubility is limited to x = 0.067, while the latter has xmax = 0.125. The
magnetism in [Bi1-xMnx]Te changes little with x, while that for
[Bi1-2xTexMnx]Te shows a clear variation, leading to ferromagnetism for x >
0.067. Magnetic hysteresis and the anomalous Hall Effect are observed for the
ferromagnetic samples.Comment: Accepted for publication in Phys. Rev.
Equivariant differential characters and symplectic reduction
We describe equivariant differential characters (classifying equivariant
circle bundles with connections), their prequantization, and reduction
Comparing phenomenological recipes with a microscopic model for the electric amplitude in strangeness photoproduction
Corrections to the Born approximation in photo-induced strangeness production
off a proton are calculated in a semi-realistic microscopic model. The vertex
corrections and internal contributions to the amplitude of the reaction are included on the one-loop level. Different
gauge-invariant phenomenological prescriptions for the modification of the Born
contribution via the introduction of form factors and contact terms are
discussed. In particular, it is shown that the popular minimal-substitution
method of Ohta corresponds to a special limit of the more realistic approach.Comment: 10 pages, 6 figures in the tex
The Geo-Ecological Risks of Oil Investments by China and the Global South: The Right to Development Revisited
Regionale input-outputanalyse. In welke regio's en sectoren heeft een vraagimpuls het hoogste rendement?
Regionaal-economisch stimuleringsbeleid is gebaat bij kennis over de te verwachten effecten van een vraagimpuls. Deze studie laat zien dat het effect van een economische impuls duidelijk verschilt per regio en per sector. Relatief grote verschillen tussen regio's bestaan met name voor de landbouw en visserij en de industrie en delfstoffenwinning. Investeren in de Randstad heeft gemiddeld gezien minder effect dan in een andere regio van Nederland, vooral vanwege de relatief kleine spin-off. Op grond van deze effectenanalyse kunnen vraagtekens gezet worden bij het huidige regionaal-economische beleid dat met name gericht is op stimulering van sectoren als transport en communicatie (in de Randstad) en de tertiaire en quartaire sector in het algemeen (dienstverlening). Stimulering van sectoren die sterk(er) gericht zijn op de binnenlandse markt en die onderdeel uitmaken of sterk verbonden zijn aan de traditionele primaire en secundaire bedrijfstakken dan op de eerder genoemde sectoren levert meer op
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