Theoretical study of reactive and nonreactive turbulent coaxial jets

The hydrodynamic properties and the reaction kinetics of axisymmetric coaxial turbulent jets having steady mean quantities are investigated. From the analysis, limited to free turbulent boundary layer mixing of such jets, it is found that the two-equation model of turbulence is adequate for most nonreactive flows. For the reactive flows, where an allowance must be made for second order correlations of concentration fluctuations in the finite rate chemistry for initially inhomogeneous mixture, an equation similar to the concentration fluctuation equation of a related model is suggested. For diffusion limited reactions, the eddy breakup model based on concentration fluctuations is found satisfactory and simple to use. The theoretical results obtained from these various models are compared with some of the available experimental data

Heavy Quarkonium Potential Model and the 1P1{}^1P_1 State of Charmonium

A theoretical explanation of the observed splittings among the P~states of charmonium is given with the use of a nonsingular potential model for heavy quarkonia. We also show that the recently observed mass difference between the center of gravity of the ${}^3P_J$ states and the ${}^1P_1$ state of $c\bar{c}$ does not provide a direct test of the color hyperfine interaction in heavy quarkonia. Our theoretical value for the mass of the ${}^1P_1$ state is in agreement with the experimental result, and its E1 transition width is 341.8~keV. The mass of the $\eta_c'$ state is predicted to be 3622.3~MeV.Comment: 15 page REVTEX documen

Natural Hazard Preparedness And Mitigation in India

Indian sub-continent is highly vulnerable to geological and hydro-meteorological hazards. Occurrences of hazard events like earthquakes, cyclones, floods, landslides have, more than often turned into disasters of varying severity with devastating impact on development process destroying human lives, property, livelihoods and social fabric. Efficient management of disasters, rather than mere response to their occurrence, has in recent decades, received an increasing attention of the national planners leading to the formulation of Disaster Management Act in 2005 by Government of India. The national policy enshrined in the Act marked a paradigm shift from the erstwhile post-disaster relief-centric approach to pro-active approach based on prevention, mitigation and preparedness. The new policy catapulted initiatives in the areas of hazard evaluation and quantification, risk assessment of built infrastructure capacity building of concerned stakeholders, structural audit and upgradation of existing unsafe buildings, post disaster damage and need assessment, updating the disaster specific codes, amending the building byelaws, land-use zoning practices of urban local bodies. The Paper summarizes the practices, institutional mechanisms and regulatory framework those emerged from the above initiatives and which are getting gradually established as accepted practices at national, state, district and local levels

N(HI) and jet power/emission in AGNs

Neutral hydrogen (HI) 21 cm absorption has been detected against more and more powerful radio jets. In this work, based on the Guppta et al. 2006a sample, we present our preliminary study of the correlations between the HI column density N(HI) and the jet power, N(HI) versus the low frequency luminosity at 408MHz, and N(HI) versus the radio luminosity at 1400MHz.Comment: 3 pages, 1 figures, Multiwavelength Variability of Blazars Guangzhou, China, Sept. 22-24, 2010; will be published by JA

A robust pseudo-inverse spectral filter applied to the Earth Radiation Budget Experiment (ERBE) scanning channels

Computer simulations of a least squares estimator operating on the ERBE scanning channels are discussed. The estimator is designed to minimize the errors produced by nonideal spectral response to spectrally varying and uncertain radiant input. The three ERBE scanning channels cover a shortwave band a longwave band and a ""total'' band from which the pseudo inverse spectral filter estimates the radiance components in the shortwave band and a longwave band. The radiance estimator draws on instantaneous field of view (IFOV) scene type information supplied by another algorithm of the ERBE software, and on a priori probabilistic models of the responses of the scanning channels to the IFOV scene types for given Sun scene spacecraft geometry. It is found that the pseudoinverse spectral filter is stable, tolerant of errors in scene identification and in channel response modeling, and, in the absence of such errors, yields minimum variance and essentially unbiased radiance estimates

Chiral Quark Model with Configuration Mixing

The implications of one gluon exchange generated configuration mixing in the Chiral Quark Model ($\chi$QM$_{gcm}$) with SU(3) and axial U(1) symmetry breakings are discussed in the context of proton flavor and spin structure as well as the hyperon $\beta$-decay parameters. We find that $\chi$QM$_{gcm}$ with SU(3) symmetry breaking is able to give a satisfactory unified fit for spin and quark distribution functions, with the symmetry breaking parameters $\alpha=.4$, $\beta=.7$ and the mixing angle $\phi=20^o$, both for NMC and the most recent E866 data. In particular, the agreement with data, in the case of $G_A/G_V, \Delta_8$, F, D, $f_s$ and $f_3/f_8$, is quite striking.Comment: 16 pages, LaTex, Table and Appendix adde

Cobalamin and Folic Acid Status in Relation to the Etiopathogenesis of Pancytopenia in Adults at a Tertiary Care Centre in North India

Background. Pancytopenia has multiple etiologies like megaloblastic anemia, aplastic anemia, leukemia, and various infections. We investigated the clinical, etiological and hematological profile including bone marrow morphology of patients with pancytopenia in relation to their vitamin B12 and folic acid status at a tertiary care referral hospital in north India. Methods. A total of 140 consecutive patients with pancytopenia were selected from June 2007 to December 2008. Bone marrow examination and other tests were carried out as warranted, including serum cobalamin and folate assays using liquid chromatography mass spectroscopy (LC MS/MS). Results. The study population consisted of 92 males and 48 females with a mean age of 32.8 years. Megaloblastic anemia 60.7%, aplastic anemia (7.8%), and leukemia (9.2%) were common causes. Infectious causes (16.4% of all cases) included leishmaniasis, HIV–AIDS, malaria and tuberculosis. Severe cobalamin deficiency (B12 < 100 pg/mL) was seen in 81% of all patients including 91.6% of patients with MA. In contrast, only 7.14% of all pancytopenic patients were folate deficient. Folate deficiency (<5 ng/mL) was seen in just 5% MA patients. Combined cobalamin and folate deficiency was seen in 5 patients (3.51%). Conclusion. Cobalamin deficiency was found to be more common in our setting and is largely underdiagnosed in the age of folate supplementation. Infectious diseases like tuberculosis, leishmaniasis, and increasingly HIV are important and treatable causes of pancytopenia. This is in contrast with the developed nations where the bulk of disease is due to malignancy or marrow aplasia