1,579 research outputs found
Investigation of Io's Auroral Hiss Emissions Due To Its Motion in Jupiter's Magnetosphere
The left-hand side of the auroral hiss emission observed by Galileo has a
frequency time shaped very similar to the funnel shape observed in the earth's
auroral region. This close similarity indicates that we can use the
whistler-mode propagation near resonance cone to locate the emission source. In
this paper the general characteristic of the whistler mode are discussed. Then
the position of the emission source has been investigated using a geometry
method that takes into account the Galileo's trajectory. Initially it is
assumed the source is a point. Then the possibility of sheet source aligned
along the magnetic field lines which are tangent to the surface of Io is
investigated. Both of two types of sources show that the whistler mode
radiation originates very close to the surface of the Io
Modeling batch annealing process using data mining techniques for cold rolled steel sheets
The annealing process is one of the important operations in production of cold rolled steel sheets, which significantly influences the final product quality of cold rolling mills. In this process, cold rolled coils are heated slowly to a desired temperature and then cooled. Modelling of annealing process (prediction of heating and cooling time and trend prediction of coil core temperature) is a very sophisticated and expensive work. Modelling of annealing process can be done by using of thermal models. In this paper, Modelling of steel annealing process is proposed by using data mining techniques. The main advantages of modelling with data mining techniques are: high speed in data processing, acceptable accuracy in obtained results and simplicity in using of this method. In this paper, after comparison of results of some data mining techniques, feed forward back propagation neural network is applied for annealing process modelling. A good correlation between results of this method and results of thermal models has been obtained
Correlation Functions and AdS/LCFT Correspondence
Correlation functions of Logarithmic conformal field theory is investigated
using the ADS/CFT correspondence and a novel method based on nilpotent weights
and 'super fields'. Adding an specific form of interaction, we introduce a
perturbative method to calculate the correlation functions.Comment: 11 pages, 4 figure
On the AdS/CFT Correspondence and Logarithmic Operator
Logarithmic conformal field theory is investigated using the AdS/CFT
correspondence and a novel method based on nilpotent weights. Using this device
we add ghost fermions and point to a BRST invariance of the theory.Comment: 8 Pages, Typos corrected, references added changes in the content of
the last sectio
Mass Exchange Dynamics of Surface and Subsurface Oil in Shallow-Water Transport
We formulate a model for the mass exchange between oil at and below the sea
surface. This is a particularly important aspect of modeling oil spills.
Surface and subsurface oil have different chemical and transport
characteristics and lumping them together would compromise the accuracy of the
resulting model. Without observational or computational constraints, it is thus
not possible to quantitatively predict oil spills based upon partial field
observations of surface and/or sub-surface oil. The primary challenge in
capturing the mass exchange is that the principal mechanisms are on the
microscale. This is a serious barrier to developing practical models for oil
spills that are capable of addressing questions regarding the fate of oil at
the large spatio-temporal scales, as demanded by environmental questions. We
use upscaling to propose an environmental-scale model which incorporates the
mass exchange between surface and subsurface oil due to oil droplet dynamics,
buoyancy effects, and sea surface and subsurface mechanics. While the mass
exchange mechanism detailed here is generally applicable to oil transport
models, it addresses the modeling needs of a particular to an oil spill model
[1]. This transport model is designed to capture oil spills at very large
spatio-temporal scales. It accomplishes this goal by specializing to
shallow-water environments, in which depth averaging is a perfectly good
approximation for the flow, while at the same time retaining mass conservation
of oil over the whole oceanic domain.Comment: 18 pages, 6 figure
Avalanche frontiers in dissipative abelian sandpile model as off-critical SLE(2)
Avalanche frontiers in Abelian Sandpile Model (ASM) are random simple curves
whose continuum limit is known to be a Schramm-Loewner Evolution (SLE) with
diffusivity parameter . In this paper we consider the dissipative
ASM and study the statistics of the avalanche and wave frontiers for various
rates of dissipation. We examine the scaling behavior of a number of functions
such as the correlation length, the exponent of distribution function of loop
lengths and gyration radius defined for waves and avalanches. We find that they
do scale with the rate of dissipation. Two significant length scales are
observed. For length scales much smaller than the correlation length, these
curves show properties close to the critical curves and the corresponding
diffusivity parameter is nearly the same as the critical limit. We interpret
this as the ultra violet (UV) limit where corresponding to .
For length scales much larger than the correlation length we find that the
avalanche frontiers tend to Self-Avoiding Walk, the corresponding driving
function is proportional to the Brownian motion with the diffusion parameter
corresponding to a field theory with . This is the infra
red (IR) limit. Correspondingly the central charge decreases from the IR to the
UV point.Comment: 11 Pages, 6 Figure
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