4,146 research outputs found
Characteristics and carbon stable isotopes of fluids in the Southern Kerala granulites and their bearing on the source of CO2
Carbon dioxide-rich inclusions commonly occur in the banded charnockites and khondalites of southern Kerala as well as in the incipient charnockites formed by desiccation of gneisses along oriented zones. The combined high density fluid inclusion isochores and the range of thermometric estimates from mineral assemblages indicate entrapment pressures in the range of 5.4 to 6.1 Kbar. The CO2 equation of state barometry closely compares with the 5 plus or minus 1 Kbar estimate from mineral phases for the region. The isochores for the high density fluid inclusions in all the three rock types pass through the P-T domain recorded by phase equilibria, implying that carbon dioxide was the dominating ambient fluid species during peak metamorphic conditions. In order to constrain the source of fluids and to evaluate the mechanism of desiccation, researchers undertook detailed investigations of the carbon stable isotope composition of entrapped fluids. Researchers report here the results of preliminary studies in some of the classic localities in southern Kerala namely, Ponmudi, Kottavattom, Manali and Kadakamon
Stable isotope studies on granulites from the high grade terrain of Southern India
Fluid inclusion and petrologic characteristics of South India granulites and their bearing on the sources of metamorphic fluids are discussed. This paper served as a review and an introduction to the next paper by D. Jackson. Jackson presented carbon isotope data from gases extracted from fluid inclusions in South Indian granulites. The uniformly low Delta C-13 values (minus 10 plus or minus 2 per mil) and the greater abundance of CO2 in the incipient charnockites are suggestive of fluid influx from an externally buffered reservoir
Paramagnetic magnetization signals and curious metastable behaviour in field-cooled magnetization of a single crystal of superconductor 2H-NbSe2
We present here some newer characteristics pertaining to paramagnetic
Meissner effect like response in a single crystal of the low Tc superconducting
compound 2H-NbSe2 via a detailed study of effects of perturbation on the
field-cooled magnetization response. In the temperature range, where an
anomalous paramagnetic magnetization occurs, the field-cooled magnetization
response is found to be highly metastable: it displays a curious tendency to
switch randomly from a given paramagnetic value to a diamagnetic or to a
different paramagnetic value, when the system is perturbed by an impulse of an
externally applied ac field. The new facets revealed in a single crystal of
2H-NbSe2 surprisingly bear a marked resemblance with the characteristics of
magnetization behaviour anticipated for the giant vortex states with multiple
flux quanta predicted to occur in mesoscopic-sized superconducting specimen and
possible transitions amongst such states.Comment: 12 pages, 9 figures, submitted to Journal of Physics: Condensed
Matte
Missing Transverse-Doppler Effect in Time-Dilation Experiments with High-Speed Ions
Recent experiments with high-speed ions have investigated potential
deviations from the time-dilation predicted by special relativity (SR). The
main contribution of this article is to show that the SR predictions are
matched by the experimental results only when the transverse Doppler effect in
the observed emissions from the ions are neglected in the analysis. However,
the Doppler effect in the emission cannot be neglected because it is similar to
the time dilation effect. Thus, the article highlights the need to consider
Doppler emission effects when validating SR time dilation using high-speed ion
experiments.Comment: 3 pages, 3 figure
Probing quark gluon plasma properties by heavy flavours
The Fokker Planck (FP) equation has been solved to study the interaction of
non-equilibrated heavy quarks with the Quark Gluon Plasma (QGP) expected to be
formed in heavy ion collisions at RHIC energies. The solutions of the FP
equation have been convoluted with the relevant fragmentation functions to
obtain the and meson spectra. The results are compared with
experimental data measured by STAR collaboration. It is found that the present
experimental data can not distinguish between the spectra obtained from
the equilibrium and non-equilibrium charm distributions. Data at lower
may play a crucial role in making the distinction between the two. The nuclear
suppression factor, for non-photonic single electron spectra
resulting from the semileptonic decays of hadrons containing heavy flavours
have been evaluated using the present formalism. It is observed that the
experimental data on nuclear suppression factor of the non-photonic electrons
can be reproduced within this formalism by enhancing the pQCD cross sections by
a factor of 2 provided the expansion of the bulk matter is governed by the
velocity of sound, . Ideal gas equation of state fails to
reproduce the data even with the enhancement of the pQCD cross sections by a
factor of 2.Comment: Minor modification of tex
- …
