Filtration studies for separation of solid particles from slurry generated in hydrometallurgical processing of ores and concentrates

Polymetallic sea nodules are a source for the recovery of valuable non-ferrous metals. In this study the sea nodule residue from the leach slurry of Indian polymetallic sea nodules is filtered to separate solids from the leach solution. Separation of solid particles from slurry generated from hydrometallurgical processing of ores and concentrates. Separation of solid particles is usually carried out by the sedimentation and filtration operation. Sedimentation of slurry is done in a graduated cylindrical vessel. In filtration the slurry is filtered to get a clear filtrate solution and solid particles. Filtration of slurries such as sea nodule residue in ammoniacal liquor (20%) and Zinc carbonate slurry in water was carried out in a Buckner funnel attached to a graduated tube connected to a vacuum pump. The study was carried out under different conditions of pressure, slurry concentration, filter media et. The filtration studies have been carried out under vacuum pressure of 8 mm Hg to 100 mm Hg and 150 mm Hg gauge; slurry concentrations of 10% , 20% and 25%. Studies were done to know the filtration characteristicssuch as rate of filtration, plugging of pores in repeated use, filter cake resistance and filter medium resistance. The cake and medium resistance were calculated using the filtration equation.The cake and medium resistances were found to depend on filter medium pressure applied and nature of particles

The Forkhead box F1 transcription factor inhibits collagen deposition and accumulation of myofibroblasts during liver fibrosis

Hepatic fibrosis is the common end stage to a variety of chronic liver injuries and is characterized by an excessive deposition of extracellular matrix (ECM), which disrupts the liver architecture and impairs liver function. The fibrous lesions are produced by myofibroblasts, which differentiate from hepatic stellate cells (HSC). The myofibroblast’s transcriptional networks remain poorly characterized. Previous studies have shown that the Forkhead box F1 (FOXF1) transcription factor is expressed in HSCs and stimulates their activation during acute liver injury; however, the role of FOXF1 in the progression of hepatic fibrosis is unknown. In the present study, we generated αSMACreER;Foxf1fl/fl mice to conditionally inactivate Foxf1 in myofibroblasts during carbon tetrachloride-mediated liver fibrosis. Foxf1 deletion increased collagen depositions and disrupted liver architecture. Timp2 expression was significantly increased in Foxf1-deficient mice while MMP9 activity was reduced. RNA sequencing of purified liver myofibroblasts demonstrated that FOXF1 inhibits expression of pro-fibrotic genes, Col1α2, Col5α2, and Mmp2 in fibrotic livers and binds to active repressors located in promotors and introns of these genes. Overexpression of FOXF1 inhibits Col1a2, Col5a2, and MMP2 in primary murine HSCs in vitro. Altogether, FOXF1 prevents aberrant ECM depositions during hepatic fibrosis by repressing pro-fibrotic gene transcription in myofibroblasts and HSCs

Equity norms in global environmental governance

Contestations over justice and equity in international environmental regimes present striking evidence of the struggle to create institutions for global environmental governance that are based on widely shared ethical standards of responsibility and accountability. Focusing on two key equity norms-the common heritage of mankind (CHM) and common but differentiated responsibility (CDR)-this paper highlights four factors that affect the influence of moral responsibility norms in global environmental regimes: (i) source and force of articulation; (ii) nature of issue-area; (iii) "moral temper" of the international community; and (iv) "fitness" of norms with the prevailing neoliberal economic idea and structure. Consequent upon the argument that the most important of all these factors is the "fitness" with the extant neoliberal order, the paper questions the assumptions of the burgeoning constructivist scholarship that tends to overemphasize the independent role of intersubjective beliefs in international politics. Further, it is suggested that the abiding "responsibility deficit" in institutions for global environmental governance is due mostly to the successful co-optation of equity norms for neoliberal ends. (c) 2008 by the Massachusetts Institute of Technology.