QCD Critical Point in a Quasiparticle Model

Recent theoretical investigations have unveiled a rich structure in the quantum chromodynamics (QCD) phase diagram which consists of quark gluon plasma (QGP) and the hadronic phases but also supports the existence of a cross-over transition ending at a critical end point (CEP). We find a too large variation in determination of the coordinates of the CEP in the temperature (T), baryon chemical potential ($\mu_{B}$) plane and, therefore, its identification in the current heavy-ion experiments becomes debatable. Here we use an equation of state (EOS) for a deconfined QGP using a thermodynamically consistent quasiparticle model involving quarks and gluons having thermal masses. We further use a thermodynamically consistent excluded volume model for the hadron gas (HG) which was recently proposed by us. Using these equations of state, a first order deconfining phase transition is constructed using Gibbs' criteria. This leads to an interesting finding that the phase transition line ends at a critical point (CEP) beyond which a cross-over region exists. Using our thermal HG model, we obtain a chemical freeze out curve and we find that the CEP lies in close proximity to this curve as proposed by some authors. The coordinates of CEP are found to lie within the reach of RHIC experiment.Comment: 15 pages, 3 figures, 1 table; minor corrections, to be appeared in Phys. Rev.

The equatorial ionospheric response over Tirunelveli to the 15 January 2010 annular solar eclipse: observations

In this paper we present a case study of the annular solar eclipse effects on the ionization of E and F regions of equatorial ionosphere over Tirunelveli [77.8° E, 8.7° N, dip 0.4° N] by means of digital ionosonde on 15 January 2010. The maximum obscuration of the eclipse at this station was 84% and it occurred in the afternoon. The E and F1 layers of the ionosphere showed very clear decrease in their electron concentrations, whereas the F2 layer did not show appreciable changes. A reduction of 30% was observed in the <I>fo</I>F1 during the maximum phase of the eclipse. During the beginning phase of the eclipse, an enhancement of 0.97 MHz was observed in the <I>fo</I>F2 as compared to that of the control days. But the <I>fo</I>F2 decreased gradually as the eclipse progressed and a decrease of 0.59 MHz was observed towards the end phase of the eclipse. Observed variations in the <I>h</I>'F2 and <I>hm</I>F2 showed lower values than the control days, although <I>hm</I>F2 was found to increase a bit during the eclipse. Observed variability in the E, F1 and F2 layer ionospheric parameters on the eclipse day and their departure from the control days are discussed as the combined effect of annular eclipse and presence of counter equatorial electrojet (CEEJ)

Subpixel Target Enhancement in Hyperspectral Images

Hyperspectral images due to their higher spectral resolution are increasingly being used for various remote sensing applications including information extraction at subpixel level. Typically whenever an object gets spectrally resolved but not spatially, mixed pixels in the images result. Numerous man made and/or natural disparatetar gets may thus occur inside such mixed pixels giving rise to subpixel target detection problem. Various spectral unmixing models such as linear mixture modeling (LMM) are in vogue to recover components of a mixed pixel. Spectral unmixing outputs both the endmember spectrum and their corresponding a bundance fractions inside the pixel. It, however, does not provide spatial distribution of these abundance fractions within a pixel. This limits the applicability of hyperspectral data for subpixel target detection. In this paper, a new inverse Euclidean distance based super-resolution mapping method has been presented. In this method, the subpixel target detection is performed by adjusting spatial distribution of abundance fraction within a pixel of an hyperspectral image. Results obtainedat different resolutions indicate that super-resolution mapping may effectively be utilized in enhancing the target detection at sub-pixel level.Defence Science Journal, 2013, 63(1), pp.63-68, DOI:http://dx.doi.org/10.14429/dsj.63.376

Laminar Dispersion in Presence of Slip and Cbemical Reactions

Concentration profiles of a solute convectively diffusing and simultaneously undergoing homogeneous and heterogeneous chemical reactions under isothermal conditions in a non-Poisuelle laminar slip flow taking place in a closed parallel-plate channel with a permeable bed are presented. It is shown that presence of slip brings about an increase in concentration across the entire cross-section of the channel. Effect of varying reaction rate parameters on concentration profiles is also discussed