45,509 research outputs found
Deciphering Deconfinement in Correlations of Conserved Charges
Diagonal and off-diagonal flavor and conserved charge susceptibilities reveal
the prevalent degrees of freedom of heated strongly interacting matter. Results
obtained from lattice simulations are compared with various model estimates in
an effort to weed down various possible pictures of a quark gluon plasma. We
argue that the vanishing of the off-diagonal quark flavor susceptibilities and
its derivatives with respect to chemical potential, at temperatures above
1.5Tc, can only be understood in a picture of a gas or liquid composed of
quasi-particles which carry the same quantum numbers as quarks and antiquarks.
A potential new observable, blind to neutral and non-strange particles, is
introduced and related via isospin symmetry to the ratio of susceptibilities of
baryonic strangeness to strangeness generated in the excited matter created at
RHIC.Comment: 5 pages, 3 figures, LATEX, To appear in the proceedings of the
International Conference on Strangeness in Quark Matter, Los Angeles, CA, Mar
26-31, 200
Surface Impedance Determination via Numerical Resolution of the Inverse Helmholtz Problem
Assigning boundary conditions, such as acoustic impedance, to the frequency
domain thermoviscous wave equations (TWE), derived from the linearized
Navier-Stokes equations (LNSE) poses a Helmholtz problem, solution to which
yields a discrete set of complex eigenfunctions and eigenvalue pairs. The
proposed method -- the inverse Helmholtz solver (iHS) -- reverses such
procedure by returning the value of acoustic impedance at one or more unknown
impedance boundaries (IBs) of a given domain, via spatial integration of the
TWE for a given real-valued frequency with assigned conditions on other
boundaries. The iHS procedure is applied to a second-order spatial
discretization of the TWEs on an unstructured staggered grid arrangement. Only
the momentum equation is extended to the center of each IB face where pressure
and velocity components are co-located and treated as unknowns. The iHS is
finally closed via assignment of the surface gradient of pressure phase over
the IBs, corresponding to assigning the shape of the acoustic waveform at the
IB. The iHS procedure can be carried out independently for different
frequencies, making it embarrassingly parallel, and able to return the complete
broadband complex impedance distribution at the IBs in any desired frequency
range to arbitrary numerical precision. The iHS approach is first validated
against Rott's theory for viscous rectangular and circular ducts. The impedance
of a toy porous cavity with a complex geometry is then reconstructed and
validated with companion fully compressible unstructured Navier-Stokes
simulations resolving the cavity geometry. Verification against one-dimensional
impedance test tube calculations based on time-domain impedance boundary
conditions (TDIBC) is also carried out. Finally, results from a preliminary
analysis of a thermoacoustically unstable cavity are presented.Comment: As submitted to AIAA Aviation 201
DESIGN AND ANTIINFLAMATORY ACTIVITY OF SOME NOVEL OXADIAZOLE DERIVATIVES – AN OVERVIEW
Oxadiazole derivates play vital role in biological field suchas anti-microbial, anti-viral, anti-tubercular, antiinflammatoryand anti-convulsant activity. Therapeuticsignificance of these clinically useful drugs in treatment ofinflammation encouraged the development of some morepotent and significant compounds. oxadiazole derivativesare remarkably effective compounds for inflammation andanalgesic activity. Extensive biochemical andpharmacological studies have confirmed that thesemolecules are effective in inflammation. Thiscomprehensive overview summarizes the chemistry ofdifferent derivatives of substitute
Cohesion of BaReH and BaMnH: Density Functional Calculations and Prediction of (MnH Salts
Density functional calculations are used to calculate the structural and
electronic properties of BaReH and to analyze the bonding in this compound.
The high coordination in BaReH is due to bonding between Re 5 states and
states of -like symmetry formed from combinations of H orbitals in the
H cage. This explains the structure of the material, its short bond lengths
and other physical properties, such as the high band gap. We compare with
results for hypothetical BaMnH, which we find to have similar bonding and
cohesion to the Re compound. This suggests that it may be possible to
synthesize (MnH salts. Depending on the particular cation, such salts
may have exceptionally high hydrogen contents, in excess of 10 weight
Fluctuations, strangeness and quasi-quarks in heavy-ion collisions from lattice QCD
We report measurements of diagonal susceptibilities for the baryon number,
chi_B, electrical charge, chi_Q, third component of isospin, chi_I,
strangeness, chi_S, and hypercharge, chi_Y, as well as the off-diagonal chi_BQ,
chi_BY, chi_BS, etc. We show that the ratios of susceptibilities in the high
temperature phase are robust variables, independent of lattice spacing, and
therefore give predictions for experiments. We also investigate strangeness
production and flavour symmetry breaking matrix elements at finite temperature.
Finally, we present evidence that in the high temperature phase of QCD the
different flavour quantum numbers are excited in linkages which are exactly the
same as one expects from quarks. We present some investigations of these
quark-like quasi particles
- …