6,689 research outputs found
Superconductivity at 5.2 K in ZrTe3 polycrystals and the effect of Cu, Ag intercalation
We report the occurrence of superconductivity in polycrystalline samples of
ZrTe3 at 5.2 K temperature at ambient pressure. The superconducting state
coexists with the charge density wave (CDW) phase, which sets in at 63K. The
intercalation of Cu or Ag, does not have any bearing on the superconducting
transition temperature but suppresses the CDW state. The feature of CDW anomaly
in these compounds is clearly seen in the DC magnetization data. Resistivity
data is analysed to estimate the relative loss of carriers and reduction in the
nested Fermi surface area upon CDW formation in the ZrTe3 and the intercalated
compounds.Comment: 5 pages, 8 figure
Accelerating dark energy models in bianchi Type-V space-time
Some new exact solutions of Einstein's field equations in a spatially
homogeneous and anisotropic Bianchi type-V space-time with minimally
interaction of perfect fluid and dark energy components have been obtained. To
prevail the deterministic solution we choose the scale factor , which yields a time dependent deceleration parameter (DP),
representing a model which generates a transition of the universe from the
early decelerating phase to the recent accelerating phase. We find that for , the quintessence model is reproducible with present and expected
future evolution of the universe. The other models (for ), we observe
the phantom scenario. The quintessence as well as phantom models approach to
isotropy at late time. For different values of , we can generate a class of
physically viable DE models. The cosmic jerk parameter in our descended model
is also found to be in good concordance with the recent data of astrophysical
observations under appropriate condition. The physical and geometric properties
of spatially homogeneous and anisotropic cosmological models are discussed.Comment: 12 pages, 6 figure
Description of Drip-Line Nuclei within Relativistic Mean-Field Plus BCS Approach
Recently it has been demonstrated, considering Ni and Ca isotopes as
prototypes, that the relativistic mean-field plus BCS (RMF+BCS) approach
wherein the single particle continuum corresponding to the RMF is replaced by a
set of discrete positive energy states for the calculation of pairing energy
provides a good approximation to the full relativistic Hartree-Bogoliubov (RHB)
description of the ground state properties of the drip-line neutron rich
nuclei. The applicability of RMF+BCS is essentially due to the fact that the
main contribution to the pairing correlations is provided by the low-lying
resonant states. General validity of this approach is demonstrated by the
detailed calculations for the ground state properties of the chains of isotopes
of O, Ca, Ni, Zr, Sn and Pb nuclei. The TMA and NL-SH force parameter sets have
been used for the effective mean-field Lagrangian. Comprehensive results for
the two neutron separation energy, rms radii, single particle pairing gaps and
pairing energies etc. are presented. The Ca isotopes are found to exhibit
distinct features near the neutron drip line whereby it is found that further
addition of neutrons causes a rapid increase in the neutron rms radius with
almost no increase in the binding energy, indicating the occurrence of halos. A
comparison of these results with the available experimental data and with the
recent continuum relativistic Hartree-Bogoliubov (RCHB) calculations amply
demonstrates the validity and usefulness of this fast RMF+BCS approach.Comment: 59 pages, 40 figure
Alpha-decay chains of and in the Relativistic Mean Field theory
In the recent experiments designed to synthesize the element 115 in the
Am+Ca reaction at Dubna in Russia, three similar decay chains
consisting of five consecutive -decays, and another different decay
chain of four consecutive -decays are detected, and the decay
properties of these synthesized nuclei are claimed to be consistent with
consecutive -decays originating from the parent isotopes of the new
element 115, and , respectively\cite{ogan.03}. Here in
the present work, the recently developed deformed RMF+BCS method with a
density-independent delta-function interaction in the pairing channel is
applied to the analysis of these newly synthesized superheavy nuclei
, , and their -decay daughter nuclei. The
calculated -decay energies and half-lives agree well with the
experimental values and with those of the macroscopic-microscopic FRDM+FY and
YPE+WS models. In the mean field Lagrangian, the TMA parameter set is used.
Particular emphasis is paid on the influence to both the ground-state
properties and energy surfaces introduced by different treatments of pairing.
Two different effective interactions in the particle-particle channel, i.e.,
the constant pairing and the density-independent delta-function interaction,
together with the blocking effect are discussed in detail.Comment: 17 pages, 5 figure
Removal of Heavy Metals from Acid Mine Drainage: A Review
ABSTRACT: Mining of coals and metals generates solid and liquid wastes that are potentially hazardous to the water resources and environment. Mine water (MW) also known as acid mine drainage (AMD) or acid rock drainage (ARD) is one of the very serious challenges of mining industries worldwide. This literature review summarises the removal of toxic metals from the mine waste water by various suitable treatment process. In order to reduce and remove the toxic heavy metals from mine waste water
A systematic study of Zr and Sn isotopes in the Relativistic Mean Field theory
The ground-state properties of Zr and Sn isotopes are studied within the
relativistic mean field theory. Zr and Sn isotopes have received tremendous
attention due to various reasons, including the predicted giant halos in the
neutron-rich Zr isotopes, the unique feature of being robustly spherical in the
region of Sn Sn and the particular interest of Sn
isotopes to nuclear astrophysics. Furthermore, four (semi-) magic neutron
numbers, 40, 50, 82 and 126, make these two isotopic chains particularly
important to test the pairing correlations and the deformations in a
microscopic model. In the present work, we carry out a systematic study of Zr
and Sn isotopes from the proton drip line to the neutron drip line with
deformation effects, pairing correlations and blocking effects for nuclei with
odd number of neutrons properly treated. A constrained calculation with
quadrupole deformations is performed to find the absolute minimum for each
nucleus on the deformation surface. All ground-state properties, including the
separation energies, the odd-even staggerings, the nuclear radii, the
deformations and the single-particle spectra are analyzed and discussed in
detail.Comment: the final version to appear in Modern Physics Letters A. more
figures, discussions, and references added. the data remain unchange
Screening of Selected Mulberry (Morus) Germplasm Varieties Through Propagation Parameters.
Nine mulberry varieties along with one check variety M5 were field tested at Bethamangala village of Kolar district, Karnataka. These mulberry varieties were evaluated for the propagation parameters, like sprouting, survival, shoot growth and rooting behaviour. Results showed that, sprouting percentage was above 95% inTR8, TR12 and S1708 mulberry varieties, while survival rate was as high as 93% in S1708. Mulberry variety S1708 recorded highest shoot length of 62.63cm and shorter shoot length was recorded in C6(35.55cm). Mulberry varieties studied exhibited considerable variations in fresh shoot and dry shoot weight. Among the mulberry varieties studied, Matigara black showed the longest root length (25.99cm) followed by TR12 (23.57cm) and TR8 (21.98cm). Numbers of roots / sapling were recorded more in Matigara black (42) and less in TR8 (14). Root volume was significantly high in Matigara black (16.27ml) and Tr20 (14.21ml) when compared to other varieties. Overall the mulberry variety S1708 showed better results in many propagation characters followed by TR8 and TR20 mulberry varieties. Key Words: Growth, mulberry germplasm; sprouting; survival; rooting; root length, root volume
Modelling of compound nucleus formation in fusion of heavy nuclei
A new model that includes the time-dependent dynamics of the single-particle
(s.p.) motion in conjunction with the macroscopic evolution of the system is
proposed for describing the compound nucleus (CN) formation in fusion of heavy
nuclei. The diabaticity initially keeps the entrance system around its contact
configuration, but the gradual transition from the diabatic to the adiabatic
potential energy surface (PES) leads to fusion or quasifission. Direct
measurements of the probability for CN formation are crucial to discriminate
between the current models.Comment: 4 pages,2 figures,1 table, Submitted to PR
- âŠ