Initial stages of cavitation damage and erosion on copper and brass tested in a rotating disk device

In view of the differences in flow and experimental conditions, there has been a continuing debate as to whether or not the ultrasonic method of producing cavitation damage is similar to the damage occurring in cavitating flow systems, namely, venturi and rotating disk devices. In this paper, the progress of cavitation damage during incubation periods on polycrystalline copper and brass tested in a rotating disk device is presented. The results indicate several similarities and differences in the damage mechanism encountered in a rotating disk device (which simulates field rotary devices) and a magnetostriction apparatus. The macroscopic erosion appears similar to that in the vibratory device except for nonuniform erosion and apparent plastic flow during the initial damage phase

Rapid Determination of Copper in Copper Ores

Low grade copper ores and copper ores in association with considerable quantities of other elements such as iron, lead, zinc and vanadium require a separational step wherein copper is generally seperated as sulphide either with sodium thiosulfate or with thiocetamide. In these methods the precipitated copper sulfide is ignited to cupric oxide, dissolved in dilute nitric acid and titrated idometrically. In a recent methorl wet oxidation of precipitated copper sulfide is effected with nitric acid ,and perchloric acid and titrated with disodium ethylene diamine tetraacetate (EDTA). The authors' work on the beneficiation of low grade copper ores. and extraction of copper, from these ores has necessitated developing a rapid and accurate method for the determination of copper. A separational step wherein cupric ion could be preci-pitated as cuprous oxide has been introduced to avoid ignition of copper sulfide to cupric oxide, which is time consuming

Climate change, mitigation and adaptation with reference to agriculture over the humid tropics - Winter School on Impact of Climate Change on Indian Marine Fisheries held at CMFRI, Cochin 18.1.2008 to 7.2.2008 -Winter School on Impact of Climate Change on Indian Marine Fisheries

The Bali road map under UNFCCC highlighted the conclusions of IPCC on climate change across the World. It indicates that the global warming is real. The Polar ice is melting and sea level will increase. One-third of our plant and animal species are likely to vanish. There will be famine around the world, particularly in Africa and central Asia. The Reduction of Emissions from Deforestation and Degradation (REDD) in developing countries is on top priority as deforestation alone may cause 20 to 25% increase in greenhouse gas emissions in the atmosphere. The second major issue is on “Adaptation Fund” designed to help developing countries dealing with impact of climate change. Therefore, it is pertinent to follow the guidelines at the regional scale so as to mitigate the ill effects of climate change on war-footing

Impact of weather extremes on Indian food grain production -Winter School on Impact of Climate Change on Indian Marine Fisheries held at CMFRI, Cochin 18.1.2008 to 7.2.2008

Climate change and variability are recent concerns of humankind. The recurrent drought and desertification threaten seriously the livelihood of over 1.2 billion people who depend on land for most of their needs. The global economy has adversely been influenced due to droughts and floods, cold and heat waves, forest fires, landslips and mudslips, icestorms, duststorms, hailstorms, thunder clouds associated with lightning and sea level ris

Equivariant map superalgebras

Suppose a group $\Gamma$ acts on a scheme $X$ and a Lie superalgebra $\mathfrak{g}$. The corresponding equivariant map superalgebra is the Lie superalgebra of equivariant regular maps from $X$ to $\mathfrak{g}$. We classify the irreducible finite dimensional modules for these superalgebras under the assumptions that the coordinate ring of $X$ is finitely generated, $\Gamma$ is finite abelian and acts freely on the rational points of $X$, and $\mathfrak{g}$ is a basic classical Lie superalgebra (or $\mathfrak{sl}(n,n)$, $n > 0$, if $\Gamma$ is trivial). We show that they are all (tensor products of) generalized evaluation modules and are parameterized by a certain set of equivariant finitely supported maps defined on $X$. Furthermore, in the case that the even part of $\mathfrak{g}$ is semisimple, we show that all such modules are in fact (tensor products of) evaluation modules. On the other hand, if the even part of $\mathfrak{g}$ is not semisimple (more generally, if $\mathfrak{g}$ is of type I), we introduce a natural generalization of Kac modules and show that all irreducible finite dimensional modules are quotients of these. As a special case, our results give the first classification of the irreducible finite dimensional modules for twisted loop superalgebras.Comment: 27 pages. v2: Section numbering changed to match published version. Other minor corrections. v3: Minor corrections (see change log at end of introduction

Geophysical and Geochemical Approach for Seawater Intrusion Assessment in the Godavari Delta Basin, A.P., India

Coastal lands around Bay of Bengal in Central Godavari Delta are mainly agriculture fields and two times annually paddy crops putting in the study area. Canals of Godavari River are the main source of water for irrigation. Geophysical and geochemical investigations were carried out in the study area to decipher subsurface geologic formation and assessing seawater intrusion. Electrical resistivity tomographic surveys carried out in the watershed-indicated low resistivity formation in the upstream area due to the presence of thick marine clays up to thickness of 20–25 m from the surface. Secondly, the lowering of resistivity may be due to the encroachment of seawater in to freshwater zones and infiltration during tidal fluctuation through mainly the Pikaleru drain, and to some extent rarely through Kannvaram and Vasalatippa drains in the downstream area. Groundwater quality analyses were made for major ions revealed brackish nature of groundwater water at shallow depth. The in situ salinity of groundwater is around 5,000 mg/l and there is no groundwater withdrawal for irrigation or drinking purpose in this area except Cairn energy pumping wells which is using for inject brackish water into the oil wells for easy exploration of oil. Chemical analyses of groundwater samples have indicated the range of salt concentrations and correlation of geophysical and borehole litholog data in the study area predicting seawater-contaminated zones and influence of in situ salinity in the upstream of study area. The article suggested further studies and research work that can lead to sustainable exploitation/use and management of groundwater resources in coastal areas

Seed nitrogen and fatty acids reflecting yield variation in groundnut (Arachis hypogaea)

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