4,815 research outputs found

    Electrolysis of Fused Anhydrous Aluminium Chloride and Chlorination of Salem Bauxite

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    Investigations carried out to determine (i)optimum condit-ions for the electrolysis of fused anhydrous aluminium chloride to yield aluminium metal and (ii) the optimum conditions for the chlorination of the ferruginous bauxite-ores from Salem District so as to eliminate selectively the chief impurities associated with these and to yield an acceptable grade of bauxite, are described. The electro-lysis experiments were carried out using chemically pure salts, to obtain reliable working results. Chlorination experiments yielded encouraging results if carried out on a mixture of the bauxite and powdered charcoal and on initially sulphided bauxite

    Performance Metrics for the Objective Assessment of Capacitive Deionization Systems

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    In the growing field of capacitive deionization (CDI), a number of performance metrics have emerged to describe the desalination process. Unfortunately, the separation conditions under which these metrics are measured are often not specified, resulting in optimal performance at minimal removal. Here we outline a system of performance metrics and reporting conditions that resolves this issue. Our proposed system is based on volumetric energy consumption (Wh/m3^3) and throughput productivity (L/h/m2^2) reported for a specific average concentration reduction, water recovery, and feed salinity. To facilitate and rationalize comparisons between devices, materials, and operation modes, we propose a nominal standard testing condition of removing 5 mM from a 20 mM NaCl feed solution at 50% water recovery for CDI research. Using this separation, we compare the desalination performance of a flow-through electrode (fte-CDI) cell and a flow between membrane (fb-MCDI) device, showing how significantly different systems can be compared in terms of generally desirable desalination characteristics. In general, we find that performance analysis must be considered carefully so to not allow for ambiguous separation conditions or the maximization of one metric at the expense of another. Additionally, for context we discuss a number of important underlying performance indicators and cell characteristics that are not performance measures in and of themselves but can be examined to better understand differences in performance

    Effects of an embedding bulk fluid on phase separation dynamics in a thin liquid film

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    Using dissipative particle dynamics simulations, we study the effects of an embedding bulk fluid on the phase separation dynamics in a thin planar liquid film. The domain growth exponent is altered from 2D to 3D behavior upon the addition of a bulk fluid, even though the phase separation occurs in 2D geometry. Correlated diffusion measurements in the film show that the presence of bulk fluid changes the nature of the longitudinal coupling diffusion coefficient from logarithmic to algebraic dependence of 1/s, where s is the distance between the two particles. This result, along with the scaling exponents, suggests that the phase separation takes place through the Brownian coagulation process.Comment: 6 pages, 5 figures. Accepted for publication in Europhys. Let

    Photodisintegration of aligned deuterons at astrophysical energies using linearly polarized photons

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    Following the model independent approach to deuteron photodisintegration with linearly polarized γ\gamma-rays, we show that the measurements of the tensor analyzing powers on aligned deuterons along with the differential cross section involve five different linear combinations of the isovector E1vj;j=0,1,2E1^j_v; j=0,1,2 amplitudes interfering with the isoscalar M1sM1_s and E2sE2_s amplitudes. This is of current interest in view of the recent experimental finding \cite{blackston1} that the three E1vjE1^j_v amplitudes are distinct and also the reported experimental observation \cite{sawatzky} on the front-back (polar angle) asymmetry in the differential cross section.Comment: 12 page

    Marine Fisheries Policy Brief-1 സമുദ്ര മത്സ്യമേഖലാ നയ പരിപ്രേക്‌ഷ്യം - 1 കേരളം (Marine Fisheries Policy Brief-1 Kerala Malayalam version)

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    Marine Fisheries Policy Brief-1 സമുദ്ര മത്സ്യമേഖലാ നയ പരിപ്രേക്‌ഷ്യം - 1 കേരളം (Marine Fisheries Policy Brief-1 Kerala Malayalam version

    Marine Fisheries Policy Brief-1 Kerala

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    Kerala which has a coastline of 590 km ranks first in marine fish production of India, contributing nearly 25% (5.81 lakh tonnes on average) to the total annual production. The export of marine products from the State earns valuable foreign exchange besides affording innumerable job opportunities in the industry. The population depending on fisheries has steadily increased over the years and stood at 6,02,234 in 2005 (Anon., 2005). Kerala has been in the forefront of absorbing innovative and new technologies in fishing practices, which have led the marine fisheries sector to take a complex structure. The 1980s was an important period in the development of marine fisheries in Kerala. In the first half of the period the motorized sector grew rapidly and became the most important sector yielding the maximum catch in 1988. By that time, ringseine became very popular in exploiting the pelagic resources and replaced the boatseines to a very great extent. Huge size of the new net (450 to 1000 m long) and large number of crew (30 to 50) needed for its operation necessitated larger boats with high capacity outboard engines (3 outboard engines of 40 hp each). This facilitated extension of fishing grounds for the motorized sector. The fishing grounds covered by the mechanised sector also extended by increasing the boat size and fishing effort and efficiency through multi-day fishing during the late 90s

    Theoretically Efficient Parallel Graph Algorithms Can Be Fast and Scalable

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    There has been significant recent interest in parallel graph processing due to the need to quickly analyze the large graphs available today. Many graph codes have been designed for distributed memory or external memory. However, today even the largest publicly-available real-world graph (the Hyperlink Web graph with over 3.5 billion vertices and 128 billion edges) can fit in the memory of a single commodity multicore server. Nevertheless, most experimental work in the literature report results on much smaller graphs, and the ones for the Hyperlink graph use distributed or external memory. Therefore, it is natural to ask whether we can efficiently solve a broad class of graph problems on this graph in memory. This paper shows that theoretically-efficient parallel graph algorithms can scale to the largest publicly-available graphs using a single machine with a terabyte of RAM, processing them in minutes. We give implementations of theoretically-efficient parallel algorithms for 20 important graph problems. We also present the optimizations and techniques that we used in our implementations, which were crucial in enabling us to process these large graphs quickly. We show that the running times of our implementations outperform existing state-of-the-art implementations on the largest real-world graphs. For many of the problems that we consider, this is the first time they have been solved on graphs at this scale. We have made the implementations developed in this work publicly-available as the Graph-Based Benchmark Suite (GBBS).Comment: This is the full version of the paper appearing in the ACM Symposium on Parallelism in Algorithms and Architectures (SPAA), 201

    The mechanism for the 3 x 3 distortion of Sn/ge (111)

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    We show that two distinct 3×33 \times 3 ground states, one nonmagnetic, metallic, and distorted, the other magnetic, semimetallic (or insulating) and undistorted, compete in α\alpha-phase adsorbates on semiconductor (111) surfaces. In Sn/Ge(111), LSDA/GGA calculations indicate, in agreement with experiment, that the distorted metallic ground state prevails. The reason for stability of this state is analysed, and is traced to a sort of bond density wave, specifically a modulation of the antibonding state filling between the adatom and a Ge-Ge bond directly underneath

    Sea truth data collection: estimation of diffuse attenuation coefficient in ocean colour mapping

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    Phytoplankton pigments in the ocean waters are the prime synthesisers in marine food chain which in turn terminate as pelagic or benthic nekton. They perform about half of the total global photosynthesis and compr is ethe upper consumption and production. These are the substances that have definite spectral characteristics and thereby govern the ocean colour
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