49,686 research outputs found
Unsteady Flow of a Dusty Viscous Liquid in a Channel Bounded by two Parallel Flat Plates
This Paper describes the unsteady motion of a dusty viscous liquid in a channel bounded by two parallel flat plates. The differential equations describing the problem are given. The liquid and the dust velocity profiles are obtained exactly and discussed in terms of the parameters of the problem
The BCS theory of q-deformed nucleon pairs - qBCS
We construct a coherent state of q-deformed zero coupled nucleon pairs
distributed in several single-particle orbits. Using a variational approach,
the set of equations of qBCS theory, to be solved self consistently for
occupation probabilities, gap parameter Delta, and the chemical potential
lambda, is obtained. Results for valence nucleons in nuclear degenerate sdg
major shell show that the strongly coupled zero angular momentum nucleon pairs
can be substituted by weakly coupled q-deformed zero angular momentum nucleon
pairs. A study of Sn isotopes reveals a well defined universe of (G, q) values,
for which qBCS converges. While the qBCS and BCS show similar results for Gap
parameter Delta in Sn isotopes, the ground state energies are lower in qBCS.
The pairing correlations in N nucleon system, increase with increasing q (for q
real).Comment: 8 pages, REVTEX, 3 eps figure
Schr\"{o}dinger cat state of trapped ions in harmonic and anharmonic oscillator traps
We examine the time evolution of a two level ion interacting with a light
field in harmonic oscillator trap and in a trap with anharmonicities. The
anharmonicities of the trap are quantified in terms of the deformation
parameter characterizing the q-analog of the harmonic oscillator trap.
Initially the ion is prepared in a Schr\"{o}dinger cat state. The entanglement
of the center of mass motional states and the internal degrees of freedom of
the ion results in characteristic collapse and revival pattern. We calculate
numerically the population inversion I(t), quasi-probabilities and
partial mutual quantum entropy S(P), for the system as a function of time.
Interestingly, small deformations of the trap enhance the contrast between
population inversion collapse and revival peaks as compared to the zero
deformation case. For \beta =3 and determines the average number
of trap quanta linked to center of mass motion) the best collapse and revival
sequence is obtained for \tau =0.0047 and \tau =0.004 respectively. For large
values of \tau decoherence sets in accompanied by loss of amplitude of
population inversion and for \tau \sim 0.1 the collapse and revival phenomenon
disappear. Each collapse or revival of population inversion is characterized by
a peak in S(P) versus t plot. During the transition from collapse to revival
and vice-versa we have minimum mutual entropy value that is S(P)=0. Successive
revival peaks show a lowering of the local maximum point indicating a
dissipative irreversible change in the ionic state. Improved definition of
collapse and revival pattern as the anharminicity of the trapping potential
increases is also reflected in the Quasi- probability versus t plots.Comment: Revised version, 16 pages,6 figures. Revte
The nuclear shell effects near the r-process path in the relativistic Hartree-Bogoliubov theory
We have investigated the evolution of the shell structure of nuclei in going
from the r-process path to the neutron drip line within the framework of the
Relativistic Hartree-Bogoliubov (RHB) theory. By introducing the quartic
self-coupling of meson in the RHB theory in addition to the non-linear
scalar coupling of meson, we reproduce the available data on the shell
effects about the waiting-point nucleus Zn. With this approach, it is
shown that the shell effects at N=82 in the inaccessible region of the
r-process path become milder as compared to the Lagrangian with the scalar
self-coupling only. However, the shell effects remain stronger as compared to
the quenching exhibited by the HFB+SkP approach. It is also shown that in
reaching out to the extreme point at the neutron drip line, a terminal
situation arises where the shell structure at the magic number is washed out
significantly.Comment: 18 pages (revtex), 8 ps figures, to appear in Phys. Rev.
Stress-stabilized sub-isostatic fiber networks in a rope-like limit
The mechanics of disordered fibrous networks such as those that make up the
extracellular matrix are strongly dependent on the local connectivity or
coordination number. For biopolymer networks this coordination number is
typically between three and four. Such networks are sub-isostatic and linearly
unstable to deformation with only central force interactions, but exhibit a
mechanical phase transition between floppy and rigid states under strain.
Introducing weak bending interactions stabilizes these networks and suppresses
the critical signatures of this transition. We show that applying external
stress can also stabilize sub-isostatic networks with only tensile central
force interactions, i.e., a rope-like potential. Moreover, we find that the
linear shear modulus shows a power law scaling with the external normal stress,
with a non-mean-field exponent. For networks with finite bending rigidity, we
find that the critical stain shifts to lower values under prestress
Bound State Solutions of Klein-Gordon Equation with the Kratzer Potential
The relativistic problem of spinless particle subject to a Kratzer potential
is analyzed. Bound state solutions for the s-wave are found by separating the
Klein-Gordon equation in two parts, unlike the similar works in the literature,
which provides one to see explicitly the relativistic contributions, if any, to
the solution in the non-relativistic limit.Comment: 6 page
Evaluation of Mulch Colour for Enhancing Winter-Strawberry Production under Polyhouse in Mid-Hills of Himachal Pradesh
Strawberry cultivation in Himachal Pradesh is mainly based on outdoor planting using hay as mulch and, very recently, using black polythene as mulch. The bulk of its production under field conditions usually occurs in April- May when market price is quite low. In an effort to make the crop remunerative through enhanced winter-production, a polyhouse experiment was set up to investigate influence of mulch colour on off-season fruiting response, fruit size and quality in strawberry (Fragaria x ananassa Duch.). Plants of cv. Chandler were planted in September, 2004. Irrigation was imposed using the given through T-Tape system, from 8.00 AM to 5.00 PM. Yellow plastic mulch significantly increased number of fruits, effected early and higher total yield compared to black or silver-over-purple plastic mulches. Un-mulched bed produced lowest yield and fruit quality. Yellow plastic mulch raised soil temperature by at least 2°C compared to the un-mulched bed
Energy efficient engine: Low-pressure turbine subsonic cascade component development and integration program
A subsonic cascade test program was conducted to provide technical data for optimizing the blade and vane airfoil designs for the Energy Efficient Engine Low-Pressure Turbine component. The program consisted of three parts. The first involved an evaluation of the low-chamber inlet guide vane. The second, was an evaluation of two candidate aerodynamic loading philosophies for the fourth blade root section. The third part consisted of an evaluation of three candidate airfoil geometries for the fourth blade mean section. The performance of each candidate airfoil was evaluated in a linear cascade configuration. The overall results of this study indicate that the aft-loaded airfoil designs resulted in lower losses which substantiated Pratt & Whitney Aircraft's design philosophy for the Energy Efficient Engine low-pressure turbine component
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