SU(2) Chiral Sigma Model Study of Phase Transition in Hybrid Stars

We use a modified SU(2) chiral sigma model to study nuclear matter component and simple bag model for quark matter constituting a neutron star. We also study the phase transition of nuclear matter to quark matter with the mixed phase characterized by two conserved charges in the interior of highly dense neutron stars. Stable solutions of Tolman-Oppenheimer-Volkoff equations representing hybrid stars are obtained with a maximum mass of 1.67$M_{\odot}$ and radius around 8.9 km.Comment: 14 pages, 5 figure

Assessment of manual load carrying and health status of women farm workers of district Sonipat (Haryana), India

In present study an assessment of manual load carrying and health status of women farm workers of Thana Kalan village, Kharkhoda tehsil in Sonipat district of Haryana was conducted. A total of forty women farm workers between 25-40 years age were selected with at least five year load carrying experience, involved in farm work, with no history of chronic disease and willingness to participate in the study. The women farm workers carried water, fodder, cow dung on daily basis and seed, fertilizer and other farm inputs and farm produce on seasonal basis. It was observed that preferable mode of load carrying was head. The quantum of load varied between 20-40 kg. Assessment of health status revealed that musculoskeletal disorder was prevalent in all the age groups. Musculoskeletal disorder namely lower back pain was observed in 87.5 per cent women workers, neck pain in 72.5 per cent women workers followed by knee (32.5%) and foot pain (25 %). The pain severity was mild in most of the women farm workers and nobody was bed ridden for back pain due to load carrying. The younger age women (25-30 years) preferred traditional way of oil massage and rest for relief from back pain and neck pain after load carrying, while older women (31-40 years) had to take rest for back pain relief. The issue of occupational health disorder associated with manual load carrying by women farm worker has to receive attention to reduce the potential health risk

Magnetotransport properties of a polarization-doped three-dimensional electron slab

We present evidence of strong Shubnikov-de-Haas magnetoresistance oscillations in a polarization-doped degenerate three-dimensional electron slab in an Al$_{x}$Ga$_{1-x}$N semiconductor system. The degenerate free carriers are generated by a novel technique by grading a polar alloy semiconductor with spatially changing polarization. Analysis of the magnetotransport data enables us to extract an effective mass of $m^{\star}=0.19 m_{0}$ and a quantum scattering time of $\tau_{q}= 0.3 ps$. Analysis of scattering processes helps us extract an alloy scattering parameter for the Al$_{x}$Ga$_{1-x}$N material system to be $V_{0}=1.8eV$

Recovery of metal values from copper converter and smelter slags by ferric chloride leaching

A study of the recovery of copper, nickel and cobalt from copper converter and smelter slags by leaching with ferric chloride is reported. The converter slag from Ghatsila, India contained 4.03% copper, 1.99% nickel and 0.48% cobalt and the smelter slag contained 1.76% copper, 0.23% nickel and 0.19% cobalt. Various parameters including the effect of stirring, leaching time, leaching temperature, concentration of ferric chloride, solid-liquid ratio and particle size, on the extraction of copper, nickel and cobalt have been studied. 92% copper, 28% nickel and 24% cobalt could be extracted from converter slag under optimum conditions, whereas 54% copper, 71% nickel and 44% cobalt could be extracted from smelter slag

Atomic and electronic structure of neutral and charged SinOm clusters

Using molecular orbital approach and the generalized gradient approximation in the density functional theory, we have calculated the equilibrium geometries, binding energies, ionization potentials, and vertical and adiabatic electron affinities of SinOm clusters (n⩽6,m⩽12). The calculations were carried out using both Gaussian and numerical form for the atomic basis functions. Both procedures yield very similar results. The bonding in SinOm clusters is characterized by a significant charge transfer between the Si and O atoms and is stronger than in conventional semiconductor clusters. The bond distances are much less sensitive to cluster size than seen for metallic clusters. Similarly, calculated energy gaps between the highest occupied and lowest unoccupied molecular orbital (HOMO-LUMO) of (SiO2)n clusters increase with size while the reverse is the norm in most clusters. The HOMO-LUMO gap decreases as the oxygen content of a SinOm cluster is lowered eventually approaching the visible range. The photoluminescence and strong size dependence of optical properties of small silica clusters could thus be attributed to oxygen defects

Geometry, electronic structure, and energetics of copper-doped aluminum clusters

Using density functional theory and generalized gradient approximation for exchange-correlation potential, we have calculated the equilibrium geometries and energetics of neutral and negatively charged AlnCu (n=11,12,13,14) clusters. Unlike the alkali atom-doped aluminum clusters in the same size range, the copper atom resides inside the aluminum cluster cage. Furthermore, the 3d and 4s energy levels of Cu hybridize with the valence electrons of Al causing a redistribution of the molecular orbital energy levels of the Aln clusters. However, this redistribution does not affect the magic numbers of AlnCu clusters that could be derived by assuming that Cu donates one electron to the valence levels of Aln clusters. This behavior, brought about by the smaller size and large ionization potential of the copper atom, contributes to the anomalous properties of AlnCu− anions: Unlike AlnX− (X=alkali atom), the mass ion intensities of AlnCu− are similar to those of Al−n. The calculated adiabatic electron affinities are also in very good agreement with experiment

Kinetics of Chlorination of Tantalum Pentoxide with Carbon Tetrachloride

Tantalum chloride is used as a feed material for the plasma reduction using hydrogen and in the chloride bath fused salt electrolysis routes to produce tantalum. Most of the tantalum, however, occurs in nature in the oxide form. The traditional chlorination process employs gaseous chlorine and carbon as reductant at high temperatures (1073-1273 K). Use of carbon tetrachloride as the chlor- inating agent is expected to reduce the chlorination tem-peratures significantly resulting in lower energy cons-umption and cost of capital equipment for chlorination. The purpose of the present study was to explore the use of carbon tetrachloride as an alternative chlorinating agent for Ta205. The kinetics of chlorination of pure tantalum pentoxide powders with carbon tetrachloride in nitrogen atmosphere was investigated in the temperature range 733-853 K and Pccia in the range 20-60 kPa. The kinetic results were found to conform to a diffusion controlled reaction model. Equilibrium conversions to chloride and the gas phase composition at different temperatures and partial pressures of CCI4 were calculated using the free energy minimisation technique