16 research outputs found
The Critical Richardson Number and Limits of Applicability of Local Similarity Theory in the Stable Boundary Layer
Measurements of atmospheric turbulence made over the Arctic pack ice during
the Surface Heat Budget of the Arctic Ocean experiment (SHEBA) are used to
determine the limits of applicability of Monin-Obukhov similarity theory (in
the local scaling formulation) in the stable atmospheric boundary layer. Based
on the spectral analysis of wind velocity and air temperature fluctuations, it
is shown that, when both of the gradient Richardson number, Ri, and the flux
Richardson number, Rf, exceed a 'critical value' of about 0.20 - 0.25, the
inertial subrange associated with the Richardson-Kolmogorov cascade dies out
and vertical turbulent fluxes become small. Some small-scale turbulence
survives even in this supercritical regime, but this is non-Kolmogorov
turbulence, and it decays rapidly with further increasing stability. Similarity
theory is based on the turbulent fluxes in the high-frequency part of the
spectra that are associated with energy-containing/flux-carrying eddies.
Spectral densities in this high-frequency band diminish as the
Richardson-Kolmogorov energy cascade weakens; therefore, the applicability of
local Monin-Obukhov similarity theory in stable conditions is limited by the
inequalities Ri < Ri_cr and Rf < Rf_cr. However, it is found that Rf_cr = 0.20
- 0.25 is a primary threshold for applicability. Applying this prerequisite
shows that the data follow classical Monin-Obukhov local z-less predictions
after the irrelevant cases (turbulence without the Richardson-Kolmogorov
cascade) have been filtered out.Comment: Boundary-Layer Meteorology (Manuscript submitted: 16 February 2012;
Accepted: 10 September 2012
Search for doubly charged Higgs boson pair production in the decay to mu(+)mu(+)mu(-)mu(-) in p(p)over-bar collisions at root s=1.96 TeV
A search for pair production of doubly charged Higgs bosons in the process p (p) over bar -->H++H---->mu(+)mu(+)mu(-)mu(-) is performed with the D0 run II detector at the Fermilab Tevatron. The analysis is based on a sample of inclusive dimuon data collected at an energy of roots=1.96 TeV, corresponding to an integrated luminosity of 113 pb(-1). In the absence of a signal, 95% confidence level mass limits of M(H-L(+/-+/-))>118.4 GeV/c(2) and M(H-R(+/-+/-))>98.2 GeV/c(2) are set for left-handed and right-handed doubly charged Higgs bosons, respectively, assuming 100% branching into muon pairs
African serum interference in the determination of chloroquine sensitivity inPlasmodium falciparum
PEG-SO3H as a catalyst in aqueous media: A simple, proficient and green approach for the synthesis of quinoline derivatives
Lithium triflate (LiOTf): a highly efficient and reusable catalytic system for the synthesis of diversified quinolines under neat conditions
Investigation of the stable atmospheric boundary layer at Halley Antarctica
Boundary-layer measurements from the Brunt Ice Shelf, Antarctica are analyzed to determine flux–profile relationships. Dimensionless quantities are derived in the standard approach from estimates of wind shear, potential temperature gradient, Richardson number, eddy diffusivities for momentum and heat, Prandtl number, mixing length and turbulent kinetic energy. Nieuwstadt local scaling theory for the stable atmospheric boundary-layer appears to work well departing only slightly from expressions found in mid-latitudes. An E E – lm l m single-column model of the stable boundary layer is implemented based on local scaling arguments. Simulations based on the first GEWEX Atmospheric Boundary-Layer Study case study are validated against ensemble-averaged profiles for various stability classes. A stability-dependent function of the dimensionless turbulent kinetic energy allows a better fit to the ensemble profiles
Wavelike Structures in the Turbulent Layer During the Morning Development of Convection at Dome C, Antarctica
Search for doubly charged higgs boson pair production in the decay to mu(+)mu(+)mu(-)mu(-) in pp collisions at sqrt[s]=1.96 TeV.
A search for pair production of doubly charged Higgs bosons in the process pp -->H(++)H(--) -->mu(+)mu(+)mu(-)mu(-) is performed with the D0 run II detector at the Fermilab Tevatron. The analysis is based on a sample of inclusive dimuon data collected at an energy of sqrt[s]=1.96 TeV, corresponding to an integrated luminosity of 113 pb(-1). In the absence of a signal, 95% confidence level mass limits of M(H(+/-+/-)(L))>118.4 GeV/c(2) and M(H(+/-+/-)(R))>98.2 GeV/c(2) are set for left-handed and right-handed doubly charged Higgs bosons, respectively, assuming 100% branching into muon pairs