5,091 research outputs found
Weak and strong regimes of incompressible magnetohydrodynamic turbulence
It is shown that in the framework of the weak turbulence theory, the
autocorrelation and cascade timescales are always of the same order of
magnitude. This means that, contrary to the general belief, any model of
turbulence which implies a large number of collisions among wave packets for an
efficient energy cascade (such as the Iroshnikov-Kraichnan model) are not
compatible with the weak turbulence theory.Comment: Accepted to Phys. Plasma
Investigating texture six zero lepton mass matrices
Texture six zero Fritzsch like as well as non Fritzsch like hermitian lepton
mass matrices (144 combinations in all) have been investigated for both
Majorana and Dirac neutrinos for their compatibility with the current neutrino
oscillation data, keeping in mind the hierarchy of neutrino masses. All the
combinations considered here for Majorana neutrino masses are ruled out by the
existing data in the case of inverted hierarchy and degenerate scenario. For
Majorana neutrinos with normal hierarchy, only 16 combinations can accommodate
the experimental data. Assuming neutrinos to be Dirac particles, normal
hierarchy, inverted hierarchy as well as degenerate neutrinos are ruled out for
all combinations of texture 6 zero hermitian mass matrices.Comment: 14 pages, 2 figure
Avalanche Initiaition Mechanism - A Finite-element Approach
The Himalayas, the longest chain of mountains in the world, experiences extensive snowfall and avalanche activity during winter. Some of these areas are densely populated, and death and destruction on large scale due to avalanche activity has been reported in these areas. One of the ways of reducing the loss of life and material due to avalanches is through prediction of avalanches. An understanding of weather forecasting, terrain, and avalanche initiation mechanism is a prerequisite for avalanche prediction. In the present paper mathematical modelling of avalanche initiation mechanism has been discussed
Investigating non-Fritzsch like texture specific quark mass matrices
A detailed investigation of all possible textures of Fritzsch-like and
non-Fritzsch like, 144 for texture 6 zero and 432 for texture 5 zero mass
matrices, have been carried out to ascertain their compatibility with the
existing quark mixing data. It seems that all the texture 6 zero possibilities
are completely ruled out whereas in the case of texture 5 zero mass matrices
the only viable possibility looks to be that of Fritzsch-like.Comment: 13 pages, 4 figures, Accepted for publication in IJMP
A Review :Design and Development of Smart Automated Door Control System For Dam
This paper focused on the controlling & monitoring system for automated dam i.e. irrigation & evaluation of river water quality department using automation (PLC & SCADA). Such as paper belongs to different types of sections , how dam door controlling works on PLC ,as forward ,how system handles section of motors i.e. DC motors, SMPS etc. Dam door controlling system also deals with the monitoring structure i.e. SCADA part of the system. SCADA provides you the visualization structure that makes safety of natural water assets becomes important issue ,on-site monitoring on water quality parameters with measured equipment
Impact of Feature Representation on Remote Sensing Image Retrieval
Remote sensing images are acquired using special platforms, sensors and are classified as aerial, multispectral and hyperspectral images. Multispectral and hyperspectral images are represented using large spectral vectors as compared to normal Red, Green, Blue (RGB) images. Hence, remote sensing image retrieval process from large archives is a challenging task. Remote sensing image retrieval mainly consist of feature representation as first step and finding out similar images to a query image as second step. Feature representation plays important part in the performance of remote sensing image retrieval process. Research work focuses on impact of feature representation of remote sensing images on the performance of remote sensing image retrieval. This study shows that more discriminative features of remote sensing images are needed to improve performance of remote sensing image retrieval process
Systems of Linear Equations over and Problems Parameterized Above Average
In the problem Max Lin, we are given a system of linear equations
with variables over in which each equation is assigned a
positive weight and we wish to find an assignment of values to the variables
that maximizes the excess, which is the total weight of satisfied equations
minus the total weight of falsified equations. Using an algebraic approach, we
obtain a lower bound for the maximum excess.
Max Lin Above Average (Max Lin AA) is a parameterized version of Max Lin
introduced by Mahajan et al. (Proc. IWPEC'06 and J. Comput. Syst. Sci. 75,
2009). In Max Lin AA all weights are integral and we are to decide whether the
maximum excess is at least , where is the parameter.
It is not hard to see that we may assume that no two equations in have
the same left-hand side and . Using our maximum excess results,
we prove that, under these assumptions, Max Lin AA is fixed-parameter tractable
for a wide special case: for an arbitrary fixed function
.
Max -Lin AA is a special case of Max Lin AA, where each equation has at
most variables. In Max Exact -SAT AA we are given a multiset of
clauses on variables such that each clause has variables and asked
whether there is a truth assignment to the variables that satisfies at
least clauses. Using our maximum excess results, we
prove that for each fixed , Max -Lin AA and Max Exact -SAT AA can
be solved in time This improves
-time algorithms for the two problems obtained by Gutin et
al. (IWPEC 2009) and Alon et al. (SODA 2010), respectively
Spin-gap behaviour in the 2-leg spin-ladder BiCu2PO6
We present magnetic suscceptibility and heat capacity data on a new S=1/2
two-leg spin ladder compound BiCu2PO6. From our susceptibility analysis, we
find that the leg coupling J1/k_B is ~ 80 K and the ratio of the rung to leg
coupling J2/J1 ~ 0.9. We present the magnetic contribution to the heat capacity
of a two-leg ladder. The spin-gap Delta/k_B =3 4 K obtained from the heat
capacity agrees very well with that obtained from the magnetic susceptibility.
Significant inter-ladder coupling is suggested from the susceptibility
analysis. The hopping integrals determined using Nth order muffin tin orbital
(NMTO) based downfolding method lead to ratios of various exchange couplings in
agreement with our experimental data. Based on our band structure analysis, we
find the inter-ladder coupling in the bc-plane J2 to be about 0.75J1 placing
the compound presumably close to the quantum critical limit.Comment: 8 pages, 5 figure
Cosmic Censorship in Higher dimension II
Generalizing earlier results on dust collapse in higher dimensions, we show
here that cosmic censorship can be restored in gravitational collapse with
tangential pressure present if we take the spacetime dimension to be .
This is under conditions to be motivated physically, such as the smoothness of
initial data from which the collapse develops. The models considered here
incorporating a non-zero tangential pressure include the Einstein cluster
spacetime.Comment: 7 pages,1 figure,revtex
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