Coal Flotation : The Status and Outlook

Coal is the principal source of energy for India and will continue to remain as at the onsat of the 21st century. But the avaluation of coal as the major domestic energy source for the next century depends among other factors on finding solution for technical problems associated with beneficiation of coal to convert it into an environ-mentally acceptable fuel. The msot affective technique for cleaning coal fines is froth flotation. but msot ofthe developments in the froth flotation tachnology is in the areas of metallic mineral flotation. Processing plant operators very often tend to over look the basic differences in characteristics of coal and metallic mineral as raw matrial for flotation treatment

Stability of a horizontal viscous fluid layer in a vertical time periodic electric field

The stability of a horizontal interface between two viscous fluids, one of which is conducting and the other is dielectric, acted upon by a vertical time-periodic electric field is considered. The two fluids are bounded by electrodes separated by a finite distance. By means of Floquet theory, the marginal stability curves are obtained, thereby elucidating the dependency of the critical voltage and wavenumber upon the fluid viscosities. The limit of vanishing viscosities is shown to be in excellent agreement with the marginal stability curves predicted by means of a Mathieu equation. The methodology to obtain the marginal stability curves developed here is applicable to any arbitrary but time periodic-signal, as demonstrated for the case of a signal with two different frequencies. As a special case, the marginal stability curves for an applied ac voltage biased by a dc voltage are depicted. It is shown that the mode coupling caused by the normal stress at the interface due to the electric field leads to appearance of harmonic modes and subharmonic modes. This is in contrast to the application of a voltage with a single frequency which always leads to a harmonic mode. Whether a harmonic or subharmonic mode is the most unstable one depends on details of the excitation signal. It is also shown that the electrode spacing has a distinct effect on the stability bahavior of the system

Scattering phase shifts in quasi-one-dimension

Scattering of an electron in quasi-one dimensional quantum wires have many unusual features, not found in one, two or three dimensions. In this work we analyze the scattering phase shifts due to an impurity in a multi-channel quantum wire with special emphasis on negative slopes in the scattering phase shift versus incident energy curves and the Wigner delay time. Although at first sight, the large number of scattering matrix elements show phase shifts of different character and nature, it is possible to see some pattern and understand these features. The behavior of scattering phase shifts in one-dimension can be seen as a special case of these features observed in quasi-one-dimensions. The negative slopes can occur at any arbitrary energy and Friedel sum rule is completely violated in quasi-one-dimension at any arbitrary energy and any arbitrary regime. This is in contrast to one, two or three dimensions where such negative slopes and violation of Friedel sum rule happen only at low energy where the incident electron feels the potential very strongly (i.e., there is a very well defined regime, the WKB regime, where FSR works very well). There are some novel behavior of scattering phase shifts at the critical energies where $S$-matrix changes dimension.Comment: Minor corrections mad

Critical Issues in Controlling Suspended Particulate Matters (SPM) from Cupola Exit Gases

Among the various industries in our country, the metallurgical industry is one of the most polluting. Since we produce about 18 million tonnes of steel per year, due to its huge production rate the iron and steel sector is a major polluting industry among the various metallurgical industries. The present paper deals with one of the most neglected metallurgical industries in our countrynamelyfoundries where very little work has been done to reduce pollution especially pollution caused by suspended particulate matters (SPM). The paper describes the results of the investigation carried out by the authors to understand the nature of pollution caused byfoundries in West Bengal. It has also been shown that SPM level from cupola exit gases can be brought down below 150 mglNm3 by proper design and operation of cupola and aided by simple and inexpensive pollution control devices. The results are based on the data collected at the demonstration plant where the pollution control system designed by the authors have been set up

A Reappraisal of the Eruptive History and Recent (1991-2009) Volcanic Eruptions of the Barren Island, Andaman Sea

The Barren Island volcano in the Western Sunda Arc has displayed explosive Strombolian eruptions for more than two decades. This recent explosive event, together with the historic and prehistoric volcanic landforms, present reliable information about explosive Strombolian eruptions and the volcanological evolution of the Barren Island volcano. This study is a re-evaluation of existing knowledge and incorporates new information and interpretations of the recent and past volcanic activity on Barren Island. Direct observations of explosive eruptions since 1991 showed discrete events of bursting and ballistic transport of blocks and formation of sustained ash plumes, indicating Strombolian and violent Strombolian eruptions. Active lava flows were not seen during the observations which, instead, reveal intact preservation of the historic lava flows. A prehistoric mafic stratocone with a central depression (caldera), a central scoria cone with summit crater and abundant basaltic lava flows of historic eruptions and the scoria cones of the recent activity are the major volcanic landforms. They bear evidence of alternating effusive and explosive activity during prehistoric times accompanied by caldera forming activity; scoria cone Strombolian activity switches over to effusive events during the historic period and exclusively Strombolian activity during recent times. The results of this study differ from previous studies that interpreted several episodes of active lava flows and Hawaiian, Plinian and Vulcanian styles of the recent eruptions. It also provides new insights into the volcanological evolution of the Barren Island volcano which is crucial in understanding the future behaviour of the volcano and risk assessment

Some Observations on the Emulsion Polymerization of Styrene In the Aqueous Phase at 50° & Low Monomer Concentration

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Novel geopolymeric building materials through synergistic utilisation of industrial waste

Synergistic utilisation of major industrial wastes generated in India, namely fly ash, blast furnace slag and red mud, has been explored to develop novel building components using geopolymerisation. These include: (a) high strength cements (b) self glazed wall tiles, and (c) pavement tiles. Fly ash was used as main source of silico-aluminate for geopolymerisation. Granulated blast furnace slag (GBFS) and red mud were used individually or in combination with fly ash to tailor properties of the developed components. Chemical and mechanical activation have been judiciously incorporated in the processing schemes through an understanding of processing-structure-property relationships. Improvement in the reactivity of fly ash by mechanical activation using highenergy mills was found to results in the formation of a compact microstructure during geopolymerisation leading to high compressive strength (above 100 MPa) in geopolymer cements. The cements also exhibited improved setting time and a very low autoclave expansion. In self-glazed wall tiles, the hard impervious glazed surface was obtained at temperature lower than 150°C by controlling the particle size distribution of solid reactants, viscosity of slurry and reaction atmosphere. The self-glazed surface showed the presence of gismodine (Na-plagioclase) phase which was absent in the main body of the tiles. In pavement tiles, fly ash and granulated blast furnace slag were used to give structural framework, whereas red mud was used to supplement the iron oxide for colouring effect and alkalis. The setting and hardening occurred due to formation of cementitious A-S-H and C-S-H gel (A = Al2O3, S = SiO2, C = CaO, H = H2O). The technologies have been developed at bench scale and efforts are underway for scaling up to pilot plant level

Performance Studies on the Crushing and Screening Circuit at South Bank Treatment Plant of Hindustan Copper Ltd.

The global energy crisis, inflation and financial diffi-culties, spiralling increase in operating costs against non-remunerative prices of the finished products are generally the constraints for expansion and modernisat- ion of any mineral processing plant today.However, a very careful look is warranted for before taking any investment decision and a prudent justification for evaluation of the full potential of any plant. The Treatment Plant at South Bank (TPSB) is a typical old plant of HCL/ICC and is the subject of present study

The presence of heterogeneous nuclear ribonucleoproteins in frontotemporal lobar degeneration with FUS positive inclusions

Frontotemporal lobar degeneration with fused in sarcoma–positive inclusions (FTLD-FUS) is a disease with unknown cause. Transportin 1 is abundantly found in FUS-positive inclusions and responsible for the nuclear import of the FET proteins of which FUS is a member. The presence of all FET proteins in pathological inclusions suggests a disturbance of transportin 1–mediated nuclear import. FUS also belongs to the heterogeneous nuclear ribonucleoprotein (hnRNP) protein family. We investigated whether hnRNP proteins are associated with FUS pathology implicating dysfunctional nuclear export in the pathogenesis of FTLD-FUS. hnRNP proteins were investigated in affected brain regions in FTLD-FUS using immunohistochemistry, biochemical analysis, and the expression analysis. We demonstrated the presence of several hnRNP proteins in pathological inclusions including neuronal cytoplasmic inclusions and dystrophic neurites. The biochemical analysis revealed a shift in the location of hnRNP A1 from the nucleus to the cytoplasm. The expression analysis revealed an increase in several hnRNP proteins in FTLD-FUS. These results implicate a wider dysregulation of movement between intracellular compartments, than mechanisms only affecting the nuclear import of FUS proteins

In silico comparative analysis of LRRK2 interactomes from brain, kidney and lung

Mutations in LRRK2 are the most frequent cause of familial Parkinson’s disease (PD), with common LRRK2 non-coding variants also acting as risk factors for idiopathic PD. Currently, therapeutic agents targeting LRRK2 are undergoing advanced clinical trials in humans, however, it is important to understand the wider implications of LRRK2 targeted treatments given that LRRK2 is expressed in diverse tissues including the brain, kidney and lungs. This presents challenges to treatment in terms of effects on peripheral organ functioning, thus, protein interactors of LRRK2 could be targeted in lieu to optimize therapeutic effects. Herein an in-silico analysis of LRRK2 direct interactors in brain tissue from various brain regions was conducted along with a comparative analysis of the LRRK2 interactome in the brain, kidney, and lung tissues. This was carried out based on curated protein–protein interaction (PPI) data from protein interaction databases such as HIPPIE, human gene/protein expression databases and Gene ontology (GO) enrichment analysis using Bingo. Seven targets (MAP2K6, MATK, MAPT, PAK6, SH3GL2, CDC42EP3 and CHGB) were found to be viable objectives for LRRK2 based investigations for PD that would have minimal impact on optimal functioning within peripheral organs. Specifically, MAPT, CHGB, PAK6, and SH3GL2 interacted with LRRK2 in the brain and kidney but not in lung tissue whilst LRRK2-MAP2K6 interacted only in the cerebellum and MATK-LRRK2 interaction was absent in kidney tissues. CDC42EP3 expression levels were low in brain tissues compared to kidney/lung. The results of this computational analysis suggest new avenues for experimental investigations towards LRRK2-targeted therapeutics