Beneficiation studies on Copper ore samples from Rajasthan

COPPER is an essential metal in modern industry.It is one of the metals in which India is deficient,with an annual production of only about 10000 tonnes against her estimated requirement of 124000 tonnes at the end of the fourth plan period. Because of the severe import restri-ctions and increased growth of copper consuming indus-tries, it has become an absolute necessity to produce this vital metal from the available deposits in India and intensive efforts are being made to raise the output to about 50000 tonnes by the end of the Fourth Plan

Predicting the Warm Forming Behavior of WE43 and AA5086 Alloys

In the present work, we have studied the formability behaviour of two types of magnesium alloys, WE43 hot rolled and WE43 cold rolled by carrying out uniaxial tensile test at elevated temperatures of 350 °C to 500 °C both experimentally and numerically at a constant strain rate of 10-3s-1. Finite element (FE) model is simulated in ABAQUS/CAE 6.7-6 using coupled temperature-displacement step at higher temperature considering material's property to be isotropic in nature. The effect of temperature on maximum flow stress and major strain at onset of necking is discussed. The true stress-strain behaviour and necking evolution through strain mapping are predicted from FE model and compared with the experimental results. The results show that with increase in temperature, the maximum flow stress decreases and necking delays with increase in limiting major strain for the Magnesium alloys. The work has been extended to predict the forming limit strains of Al 5086 alloy only on the negative minor strain region using M-K (Marciniak and Kuczynski) concept. An FE model based on M-K concept is simulated at 20 °C, 150 °C and 200 °C using coupled temperature-displacement step considering anisotropic sheet material. A groove is created in the middle of the model with an optimized f value of 0.99, after much iteration. The forming limit strains from such FE simulations are compared with the available experimental data. The results are encouraging providing scope for further improvements in modelling

Multi-Scaled Explorations of Binding-Induced Folding of Intrinsically Disordered Protein Inhibitor IA3 to its Target Enzyme

Biomolecular function is realized by recognition, and increasing evidence shows that recognition is determined not only by structure but also by flexibility and dynamics. We explored a biomolecular recognition process that involves a major conformational change – protein folding. In particular, we explore the binding-induced folding of IA3, an intrinsically disordered protein that blocks the active site cleft of the yeast aspartic proteinase saccharopepsin (YPrA) by folding its own N-terminal residues into an amphipathic alpha helix. We developed a multi-scaled approach that explores the underlying mechanism by combining structure-based molecular dynamics simulations at the residue level with a stochastic path method at the atomic level. Both the free energy profile and the associated kinetic paths reveal a common scheme whereby IA3 binds to its target enzyme prior to folding itself into a helix. This theoretical result is consistent with recent time-resolved experiments. Furthermore, exploration of the detailed trajectories reveals the important roles of non-native interactions in the initial binding that occurs prior to IA3 folding. In contrast to the common view that non-native interactions contribute only to the roughness of landscapes and impede binding, the non-native interactions here facilitate binding by reducing significantly the entropic search space in the landscape. The information gained from multi-scaled simulations of the folding of this intrinsically disordered protein in the presence of its binding target may prove useful in the design of novel inhibitors of aspartic proteinases

Reduction of Iron content in a Manganese ore sample from M/s. National Carbon Co., Calcutta

A Sample of manganese ore assaying 52.09% Mn, 74.50% MnO2, 5.9% Fe, 2.3% Al2O3 and 2.8% SiO2 was received from M/s. National Carbon Co., Calcutta to investigate the possibility of reducing its iron content by physical methods so that it could be employed in dry cell industry. Petrological examination of the sample revealed that pyrolusite was the principal manganese manganite. Hematite, magnetite and goethite constituted the ferruginous gangue and the siliceous gangue consisted mainly of muscovite and quartz. Straight wet magnetic separation of the original sample (mostly 6 mesh) as well as after grinding to -35 mesh size yielded concentrates assaying 53.6% Mn, 4.6% Fe and 53.7% Mn, 4.5% Fe with recoveries of 88.5% and 94.2% respectively. Dry magnetic separation after desliming of -35 mesh ground sample produced a concentrate assaying 54.9% Mn and 3.7% Fe with a recovery of only 61.4% Mn. Tabling followed by magnetic separation of the table concentrate as well as slime yielded the best result in a combined non-magnetic manganese concentrate assaying 54.55% Mn and 3.6% Fe with a recovery of 78.2% Mn