9,925 research outputs found
Characteristics of the motions, turbulence intensity, diffusivity, flux of momentum and sensible heat in the upper atmosphere
Analyses of the meteorological rocket data obtained from an experiment conducted at 3-hour intervals at 8 western meridional rocket stations are presented. Large variations in the meridional wind contribute substantially to overall turbulence in the tropical stratosphere. The solar semidiurnal component of wind oscillations in the tropics was observed to be much higher than predicted by theory, often exceeding the magnitude of the diurnal amplitude throughout the stratosphere. The observed value of the solar diurnal amplitude in the stratosphere was in line with theoretical prediction. The solar terdiurnal amplitudes for temperature, meridional and zonal winds were non-negligible and must be considered in any harmonic analysis. Phase angle variation with height was rapid for all harmonics; however, there was general agreement between predicted and observed phase angles. Because of large changes in the mean winds in the mesosphere with season, harmonic determinations are difficult. There appear to be large zonal wind changes even within the same season as mentioned previously. Turbulence diffusivity in the upper stratosphere is greater near the equator than in the mid-latitudes
QCD Glueball Masses from AdS-6 Black Hole Description
By using the generalized version of gauge/gravity correspondence, we study
the mass spectra of several typical QCD glueballs in the framework of
AdS black hole metric of Einstein gravity theory. The obtained glueball
mass spectra are numerically in agreement with those from the AdS
black hole metric of the 11-dimensional supergravity.Comment: 10 pages, references updated and minor change
The effects of natural, forced and thermoelectric magnetohydrodynamic convection during the solidification of thin sample alloys
Using a fully coupled transient 3-dimensional numerical model, the effects of convection on the microstructural evolution of a thin sample of Ga-In25%wt. was predicted. The effects of natural convection, forced convection and thermoelectric magnetohydrodynamics were investigated numerically. A comparison of the numerical results is made to experimental results for natural convection and forced convection. In the case of natural convection, density variations within the liquid cause plumes of solute to be ejected into the bulk. When forced convection is applied observed effects include the suppression of solute plumes, preferential secondary arm growth and an increase in primary arm spacing. These effects were observed both numerically and experimentally. By applying an external magnetic field inter-dendritic flow is generated by thermoelectrically induced Lorentz forces, while bulk flow experiences an electromagnetic damping force. The former causes preferential secondary growth, while the latter slows the formation of solute plumes. This work highlights that the application of external forces can be a valuable tool for tailoring the microstructure and ultimately the macroscopic material properties
Discovering the Higgs Bosons of Minimal Supersymmetry with Muons and a Bottom Quark
We investigate the prospects for the discovery at the CERN Large Hadron
Collider of a neutral Higgs boson produced with one bottom quark followed by
Higgs decay into a muon pair. We work within the framework of the minimal
supersymmetric model. The dominant physics background from the production of , , j=g,u,d,s,c, and is calculated
with realistic acceptance cuts. Promising results are found for the CP-odd
pseudoscalar () and the heavier CP-even scalar () Higgs bosons with
masses up to 600 GeV. This discovery channel with one energetic bottom quark
greatly improves the discovery potential of the LHC beyond the inclusive
channel .Comment: Version to appear in Phys. Rev. Let
Vibration of a circular cylindrical elastic tank, partially filled with an incompressible fluid, undergoing an axial acceleration composed of a uniform and a periodic component technical memorandum no. 102
Forced vibration of circular cylindrical elastic shell partially filled with incompressible liquid and initially at rest in uniform gravitational fiel
The Chern-Simons Coefficient in Supersymmetric Non-abelian Chern-Simons Higgs Theories
By taking into account the effect of the would be Chern-Simons term, we
calculate the quantum correction to the Chern-Simons coefficient in
supersymmetric Chern-Simons Higgs theories with matter fields in the
fundamental representation of SU(n). Because of supersymmetry, the corrections
in the symmetric and Higgs phases are identical. In particular, the correction
is vanishing for N=3 supersymmetric Chern-Simons Higgs theories. The result
should be quite general, and have important implication for the more
interesting case when the Higgs is in the adjoint representation.Comment: more references and explanation about rgularization dpendence are
included, 13 pages, 1 figure, latex with revte
Higgs Boson Discovery Potential of LHC in the Channel
We discuss the SM Higgs discovery potential of LHC in the reaction when the jet is observed at sufficiently high to
be reliably identified. We conclude that this channel gives promising discovery
possibilities for the Higgs boson mass range 100-140 GeV, during LHC operation
at a low luminosity. With 30 fb of accumulated data and for
GeV about 100 signal events could be observed with the number of background
events larger by a factor of 2 only, showing a signal significance
. We use the difference of distributions in the partonic
subprocess energy for the signal and background for a better
separation of the signal.Comment: 15 pages including 6 figures, LaTeX, use epsfig.sty. To appear in
Phys.Lett.B. In this replacement minor LaTeX improvements are mad
Developing and utilizing an Euler computational method for predicting the airframe/propulsion effects for an aft-mounted turboprop transport. Volume 2: User guide
This manual explains how to use an Euler based computational method for predicting the airframe/propulsion integration effects for an aft-mounted turboprop transport. The propeller power effects are simulated by the actuator disk concept. This method consists of global flow field analysis and the embedded flow solution for predicting the detailed flow characteristics in the local vicinity of an aft-mounted propfan engine. The computational procedure includes the use of several computer programs performing four main functions: grid generation, Euler solution, grid embedding, and streamline tracing. This user's guide provides information for these programs, including input data preparations with sample input decks, output descriptions, and sample Unix scripts for program execution in the UNICOS environment
How Unsplittable-Flow-Covering helps Scheduling with Job-Dependent Cost Functions
Generalizing many well-known and natural scheduling problems, scheduling with
job-specific cost functions has gained a lot of attention recently. In this
setting, each job incurs a cost depending on its completion time, given by a
private cost function, and one seeks to schedule the jobs to minimize the total
sum of these costs. The framework captures many important scheduling objectives
such as weighted flow time or weighted tardiness. Still, the general case as
well as the mentioned special cases are far from being very well understood
yet, even for only one machine. Aiming for better general understanding of this
problem, in this paper we focus on the case of uniform job release dates on one
machine for which the state of the art is a 4-approximation algorithm. This is
true even for a special case that is equivalent to the covering version of the
well-studied and prominent unsplittable flow on a path problem, which is
interesting in its own right. For that covering problem, we present a
quasi-polynomial time -approximation algorithm that yields an
-approximation for the above scheduling problem. Moreover, for
the latter we devise the best possible resource augmentation result regarding
speed: a polynomial time algorithm which computes a solution with \emph{optimal
}cost at speedup. Finally, we present an elegant QPTAS for the
special case where the cost functions of the jobs fall into at most
many classes. This algorithm allows the jobs even to have up to many
distinct release dates.Comment: 2 pages, 1 figur
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