8,441 research outputs found
The irreversible thermodynamics of curved lipid membranes
The theory of irreversible thermodynamics for arbitrarily curved lipid
membranes is presented here. The coupling between elastic bending and
irreversible processes such as intra-membrane lipid flow, intra-membrane phase
transitions, and protein binding and diffusion is studied. The forms of the
entropy production for the irreversible processes are obtained, and the
corresponding thermodynamic forces and fluxes are identified. Employing the
linear irreversible thermodynamic framework, the governing equations of motion
along with appropriate boundary conditions are provided.Comment: 62 pages, 4 figure
Processing of Electronic Waste(E-Waste)
Rapid growth of information and telecommunication techn-ology has penetrated nearly every aspect of modern life even in the most remote area of the developing countries. The advancement of the technology has led to rapid decrease in the product lifetime and generating large quantity of waste electronic equipment (e-waste). The rapid technological progress forced manufacturer for production of new units, which ultimately adds to the number of old electronic equipment destined for land fills/recycling. The typical life span of a computer in the advanced countries is about 2 years. As the old PC, mobile, laptop and other electronic equipments become obsolete, they are replaced by the new one and added to the quantity of e-waste. The consumer electronics is now the fastest growing sector of municipal solid waste in both developed and developing countries. The e-waste is
a global concern today and it will have a far reaching adverse impact on the environment if not dealt with immediately
Lead Zinc Extraction Processes
Zinc and lead are the two most widely used non-ferrous metals after aluminium and copper as vital materials in everyday life. They are mined and smelted in many countr-ies in both the developed and developing world. Both pyrometallurgical as well as hydrometallurgical methods
are used for production of lead zinc depending on the type of raw material used as a charge. In the pyrometallurgical process, ore concentrate containing lead, zinc, or both is fed, in some cases after sintering, into a primary smelt-er. Lead concentrations can be 50-70%, and the sulfur content of sulfidic ores is in the range of 15-20%. Zinc concentration is in the range of 40-60%, with sulfur con-tent in sulfidic ores in the range of 26-34%. Ores with a mixture of lead and zinc concentrate usually have lower respective metal concentrations. During sintering, a blast of hot air or oxygen is used to oxidize the sulfur present in the feed to sulfur dioxide (SO2). An increasing propor-tion of the supply of both metals (over 50% for lead and 30% for zinc) is being met by recycling. Consumption is predominantly in industrialised countries but is increa-sing rapidly in the developed world
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