2,778 research outputs found
Groundstate and Collective Modes of a Spin-Polarized Dipolar Bose-Einstein Condensate in a Harmonic Trap
We report new results for the Thomas-Fermi groundstate and the quadrupolar
modes of density oscillations of a spin- polarized dipolar interacting
Bose-Einstein condensate for the case when the external magnetic field is not
orientated parallel to a principal axis of a harmonic anisotropic trap.Comment: Final version, published in Physical Review
Dissipation in Compressible MHD Turbulence
We report results of a three dimensional, high resolution (up to 512^3)
numerical investigation of supersonic compressible magnetohydrodynamic
turbulence. We consider both forced and decaying turbulence. The model
parameters are appropriate to conditions found in Galactic molecular clouds. We
find that the dissipation time of turbulence is of order the flow crossing time
or smaller, even in the presence of strong magnetic fields. About half the
dissipation occurs in shocks. Weak magnetic fields are amplified and tangled by
the turbulence, while strong fields remain well ordered.Comment: 5 pages, 3 Postscript figures, LaTeX, accepted by Ap.J.Let
The spatial correlations in the velocities arising from a random distribution of point vortices
This paper is devoted to a statistical analysis of the velocity fluctuations
arising from a random distribution of point vortices in two-dimensional
turbulence. Exact results are derived for the correlations in the velocities
occurring at two points separated by an arbitrary distance. We find that the
spatial correlation function decays extremely slowly with the distance. We
discuss the analogy with the statistics of the gravitational field in stellar
systems.Comment: 37 pages in RevTeX format (no figure); submitted to Physics of Fluid
Yield and quality improvement in Bt cotton through foliar application of trifloxystrobin and tebuconazole
In agriculture, fungi can cause serious damage, resulting in critical losses of yield, quality and profit. Fungicides help in reducing the damage caused by fungus, reduce the yield loss and play a major role in quality improvement. The present investigation was carried out at Tamil Nadu Agricultural University to evaluate the influence of trifloxystrobin 50% + tebuconazole 25% (Nativo 75WG) on the yield and quality improvement on Bunny hybrid Bt cotton. Nativo 75WG was applied on the leaves of cotton plants at 40-60 (DAS) and 60-80 (DAS) at the concentration of 250, 300, 350 g/ha and Carbendazim @ 500 g/ha. The observations recorded were related to yield and quality attributes in all treatments. The application of Nativo @ 300 g/ha showed a significant increase in boll weight (4.86 g), lint yield per boll (3.86 g boll-1) and lint per plant (138.48 g plant -1) than other treatments. With respect to seed cotton yield and harvest index (0.37 %), the Nativo @ 300 g/ha registered a higher yield (20.2 %) and HI than control under the irrigated situation. Foliar application of treatments during the flowering stage (40-60 DAS) and boll formation stages (60-80 DAS) had increased the quality parameters such as fiber length (2.5% staple length, 50 % staple length) and fiber strength. Further, the foliar spray of Nativo @ 300 g/ha applied to bunny hybrid Bt cotton had resulted in a higher yield (2920.15 kg ha-1) due to an increase in leaf area index, greenness of leaf and higher dry matter production of the plant
Gravitational Collapse of a Massless Scalar Field and a Perfect Fluid with Self-Similarity of the First Kind in (2+1) Dimensions
Self-similar solutions of a collapsing perfect fluid and a massless scalar
field with kinematic self-similarity of the first kind in 2+1 dimensions are
obtained. Their local and global properties of the solutions are studied. It is
found that some of them represent gravitational collapse, in which black holes
are always formed, and some may be interpreted as representing cosmological
models.Comment: 13 page
Solving the Darwin problem in the first post-Newtonian approximation of general relativity
We analytically calculate the equilibrium sequence of the corotating binary
stars of incompressible fluid in the first post-Newtonian(PN) approximation of
general relativity. By calculating the total energy and total angular momentum
of the system as a function of the orbital separation, we investigate the
innermost stable circular orbit for corotating binary(we call it ISCCO). It is
found that by the first PN effect, the orbital separation of the binary at the
ISCCO becomes small with increase of the compactness of each star, and as a
result, the orbital angular velocity at the ISCCO increases. These behaviors
agree with previous numerical works.Comment: 33 pages, revtex, 4 figures(eps), accepted for publication in Phys.
Rev.
Analytic treatment of complete and incomplete geodesics in Taub-NUT space-times
We present the complete set of analytical solutions of the geodesic equation
in Taub-NUT space-times in terms of the Weierstrass elliptic function. We
systematically study the underlying polynomials and characterize the motion of
test particles by its zeros. Since the presence of the "Misner string" in the
Taub-NUT metric has led to different interpretations, we consider these in
terms of the geodesics of the space-time. In particular, we address the
geodesic incompleteness at the horizons discussed by Misner and Taub, and the
analytic extension of Miller, Kruskal and Godfrey, and compare with the
Reissner-Nordstr\"om space-time.Comment: 22 pages, 14 figures, accepted for publication in PR
Bend and splay elastic constants of a discotic nematic
We report the dielectric constants and the splay and bend elastic constants of hexan-dodecanoyloxy truxene in the nematic phase, which occurs between two columnar phases. The dielectric anisotropy is positive. The elastic constants are ∼10−7 dyne, which is of the same order as for nematics of rod-like molecules. Further, k33 > k11, probably as a consequence of the columnar short range order in the medium
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