Computer aided Design and Optimization of Mineral Processing Plants by a State of the Art Simulator

Tata Research Development and Design Centre (TRDDC) has developed a state of the art mineral processing simulator called SimL8. It performs modelling, simulation and optimisation functions and provides viable strategies for enhancement of the performance of mineral processing plants. A number of case studies on plant diagnostics, grinding,classification, flotation and pressure filtration are taken up to demonstrate the utility of modelling and simulation on SimL8 platform

Regularities in pressure filtration of fine and colloidal suspensions

A number of interesting and potentially useful regularities have been observed in high pressure batch filtration of fine and colloidal suspensions carried out to equilibrium under a wide variety of physical and chemical process conditions. Two such regularities are described here. The first regular behavior, demonstrated by a large number of colloidal suspensions, can be represented by the Pareto profile, which relates filtration rate with solid content of filter cake at equilibrium. The profile is found to be a strong function of material fineness but is seemingly independent of physical and chemical process conditions. Since it can be treated as a constrained performance benchmark for the filtration of a suspension, it is germane for evaluating the filtration process in terms of two of its more important process measures, namely, kinetics and maximum extent of dewatering that is achievable. The Pareto regularity reflects the fact that in general it is not feasible to improve both measures simultaneously in a batch filtration which is driven to equilibrium, and any process modification may improve one measure but invariably at the expense of the other. The second regular behavior, namely, self-similarity in pressure filtration is demonstrated for filtration of wide variety of varying materials and process conditions. Simple transformation and scaling of slurry filtration data with critical solid volume fraction and critical time at the transition from cake formation stage to cake consolidation stage translate the filtration curves into a form which are remarkably self-similar. This self-preserving behavior is demonstrated for a wide variety of experimental data under varying physical and chemical process conditions for different colloidal systems. Some implications of the regularities are discussed

Solving relativistic hydrodynamic equation in presence of magnetic field for phase transition in a neutron star

Hadronic to quark matter phase transition may occur inside neutron stars (NS) having central densities of the order of 3-10 times normal nuclear matter saturation density ($n_0$). The transition is expected to be a two-step process; transition from hadronic to 2-flavour matter and two-flavour to $\beta$ equilibrated charge neutral three-flavour matter. In this paper we concentrate on the first step process and solve the relativistic hydrodynamic equations for the conversion front in presence of high magnetic field. Lorentz force due to magnetic field is included in the energy momentum tensor by averaging over the polar angles. We find that for an initial dipole configuration of the magnetic field with a sufficiently high value at the surface, velocity of the front increases considerably.Comment: 16 pages, 4 figures, same as published version of JPG, J. Phys. G: Nucl. Part. Phys. 39 (2012) 09520

Improved Protection from Velogenic Newcastle Disease Virus Challenge Following Multiple Immunizations With Plasmid DNA Encoding for F And HN Genes

Specific-pathogen free (SPF) chicken were inoculated with the plasmid combination and challenged with velogenic NDV. The antibody level against NVD was measured using commercial enzyme linked immunosorbent assay (ELISA). In the first immunization regimen, SPF chickens inoculated twice with NDV-F or NDV-HN constructs elicited antibody responses 1 week after the second injection. However, the levels of the antibody were low and did not confer significant protection from the lethal challenge. In addition, admininistration of the plasmid constructs with Freund’s adjuvant did not improve the level of protection. In the second immunization regimen, chickens inoculsted trice with the plasmid constructs emulsified with Freund”s adjuvant induced significant antibody titers after the third injection. Three out of nine (33.3 %) chickensvaccinated with pEGFP-HN, five of ten (50.0%) chicken vaccinated with pEGFP-F and nine of ten (90.0%) chicken vaccinated with combined pEGFP-F and pEGFP-HN were protected from the challenge. No significant differences in the levels of protection were observed when the chicken were vaccinated with linearized pEGFP-F. the results suggested that more than two injections with both F and HN encoding plasmid DNA were required to induce level of antibodies for protection against velogenic NDV in chickens

Coupled plasma filtration adsorption (CPFA) plus continuous veno-venous haemofiltration (CVVH) versus CVVH alone as an adjunctive therapy in the treatment of sepsis

To compare the efficacy of Coupled Plasma Filtration and Adsorption (CPFA) plus Continuous Veno-Venous Haemofiltration (CVVH) versus CVVH alone as an adjunct treatment of sepsis in terms of haemodynamic stability, inotropic requirement and inflammatory mediators. Design and Methods: Prospective randomized controlled trial involving septic patients with/without acute kidney injury (AKI) whom were randomized to receive CPFA + CVVH or CVVH alone. Haemodynamic parameters including inotropic requirements and inflammatory mediators [procalcitonin (PCT) and C reactive protein (CRP)] were measured. Results: Twenty-three patients [CPFA + CVVH (n = 11), CVVH (n = 12)] were enrolled. Haemodynamic stability occurred earlier and sustained in the CPFA + CVVH group with an increase in diastolic blood pressure (p = 0.001 vs. p = 0.226) and mean arterial pressure (p = 0.001 vs. p = 0.575) at the end of treatment with no increment in inotropic requirement. Both groups had a reduction in PCT and CRP (CPFA + CVVH: p = 0.003, p = 0.026 and CVVH: p = 0.008, p = 0.071 respectively). The length of intensive care unit stay, hospital stay and 30 day outcomes were similar between the groups. There was an inverse association between serum albumin and CRP (p = 0.018). Serum albumin positively correlated with systolic blood pressure (p = 0.012) and diastolic blood pressure (p = 0.009). We found a trend between CRP and length of hospital stay (p = 0.056). Patients with a lower PCT at 24 h had a better outcome (survival) than those with a higher PCT (p = 0.045). Conclusion: CPFA is a feasible, albeit expensive adjunctive extracorporeal treatment that may be superior to CVVH alone in the treatment of severe sepsis

Relics of the Cosmological QCD Phase Transition

The abundance and size distribution of quark nuggets (QN), formed a few microseconds after the big bang due to first order QCD phase transition in the early universe, has been estimated. It appears that stable QNs could be a viable candidate for cosmological dark matter. The evolution of baryon inhomogeneity due to evaporated (unstable) QNs are also examined.Comment: To appear in Physical Review

Aerosol Chemistry over a High Altitude Station at Northeastern Himalayas, India

BACKGROUND: There is an urgent need for an improved understanding of the sources, distributions and properties of atmospheric aerosol in order to control the atmospheric pollution over northeastern Himalayas where rising anthropogenic interferences from rapid urbanization and development is becoming an increasing concern. METHODOLOGY/PRINCIPAL FINDINGS: An extensive aerosol sampling program was conducted in Darjeeling (altitude approximately 2200 meter above sea level (masl), latitude 27 degrees 01'N and longitude 88 degrees 15'E), a high altitude station in northeastern Himalayas, during January-December 2005. Samples were collected using a respirable dust sampler and a fine dust sampler simultaneously. Ion chromatograph was used to analyze the water soluble ionic species of aerosol. The average concentrations of fine and coarse mode aerosol were found to be 29.5+/-20.8 microg m(-3) and 19.6+/-11.1 microg m(-3) respectively. Fine mode aerosol dominated during dry seasons and coarse mode aerosol dominated during monsoon. Nitrate existed as NH(4)NO(3) in fine mode aerosol during winter and as NaNO(3) in coarse mode aerosol during monsoon. Gas phase photochemical oxidation of SO(2) during premonsoon and aqueous phase oxidation during winter and postmonsoon were the major pathways for the formation of SO(4)(2-) in the atmosphere. Long range transport of dust aerosol from arid regions of western India was observed during premonsoon. The acidity of fine mode aerosol was higher in dry seasons compared to monsoon whereas the coarse mode acidity was higher in monsoon compared to dry seasons. Biomass burning, vehicular emissions and dust particles were the major types of aerosol from local and continental regions whereas sea salt particles were the major types of aerosol from marine source regions. CONCLUSIONS/SIGNIFICANCE: The year-long data presented in this paper provide substantial improvements to the heretofore poor knowledge regarding aerosol chemistry over northeastern Himalayas, and should be useful to policy makers in making control strategies