16,415 research outputs found

    Long-term evolution of highly alkaline steel slag drainage waters

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    © 2015, Springer International Publishing Switzerland. The disposal of slag generated by the steel industry can have negative consequences upon the surrounding aquatic environment by the generation of high pH waters, leaching of potentially problematic trace metals, and rapid rates of calcite precipitation which smother benthic habitats. A 36-year dataset was collated from the long-term ambient monitoring of physicochemical parameters and elemental concentrations of samples from two steel slag leachate-affected watercourses in northern England. Waters were typified by elevated pH ( > 10), high alkalinity, and were rich in dissolved metals (e.g. calcium (Ca), aluminium (Al), and zinc (Zn)). Long-term trend analysis was performed upon pH, alkalinity, and Ca concentration which, in addition to Ca flux calculations, were used to highlight the longevity of pollution arising as a result of the dumping and subsequent leaching of steel slags. Declines in calcium and alkalinity have been modest over the monitoring period and not accompanied by significant declines in water pH. If the monotonic trends of decline in alkalinity and calcium continue in the largest of the receiving streams, it will be in the region of 50–80 years before calcite precipitation would be expected to be close to baseline levels, where ecological impacts would be negligible

    A note on leapfrogging vortex rings

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    In this paper we provide examples, by numerical simulation using the Navier-Stokes equations for axisymmetric laminar flow, of the 'leapfrogging' motion of two, initially identical, vortex rings which share a common axis of symmetry. We show that the number of clear passes that each ring makes through the other increases with Reynolds number, and that as long as the configuration remains stable the two rings ultimately merge to form a single vortex ring

    Short-Chained Oligo(Ethylene Oxide)-Functionalized Gold Nanoparticles: Realization Of Significant Protein Resistance

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    Protein corona formed on nanomaterial surfaces play an important role in the bioavailability and cellular uptake of nanomaterials. Modification of surfaces with oligoethylene glycols (OEG) are a common way to improve the resistivity of nanomaterials to protein adsorption. Short-chain ethylene oxide (EO) oligomers have been shown to improve the protein resistance of planar Au surfaces. We describe the application of these EO oligomers for improved protein resistance of 30 nm spherical gold nanoparticles (AuNPs). Functionalized AuNPs were characterized using UV-Vis spectroscopy, dynamic light scattering (DLS), and zeta potential measurements. Capillary electrophoresis (CE) was used for separation and quantitation of AuNPs and AuNP-protein mixtures. Specifically, nonequilibrium capillary electrophoresis of equilibrium mixtures (NECEEM) was employed for the determination of equilibrium and rate constants for binding between citrate-stabilized AuNPs and two model proteins, lysozyme and fibrinogen. Semi-quantitative CE analysis was carried out for mixtures of EO-functionalized AuNPs and proteins, and results demonstrated a 2.5-fold to 10-fold increase in protein binding resistance to lysozyme depending on the AuNP surface functionalization and a 15-fold increase in protein binding resistance to fibrinogen for both EO oligomers examined in this study

    A Ka-band (32 GHz) beacon link experiment (KABLE) with Mars Observer

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    A proposal for a Ka-Band (32 GHz) Link Experiment (KABLE) with the Mars Observer mission was submitted to NASA. The experiment will rely on the fourth harmonic of the spacecraft X-band transmitter to generate a 33.6 GHz signal. The experiment will rely also on the Deep Space Network (DSN) receiving station equipped to simultaneously receive X- and Ka-band signals. The experiment will accurately measure the spacecraft-to-Earth telecommunication link performance at Ka-band and X-band (8.4 GHz)

    Population Update, Report Number 4

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    The preliminary report* from the 1980 U.S. Census for South Dakota shows that the state\u27s population increased 21,960 persons, or 3.3%, from 1970 to 1980. Significant changes have taken place in South Dakota\u27s population during this past decade. Basic changes have occurred primarily in birth rate and migration. In the 1950\u27s South Dakota experienced a small population increase (4.3%, Table 1) in spite of a high loss through out-migration. The out-migration was compensated for by the high birth rate of the “baby boom.” By 1960 the baby boom had peaked; and the lower fertility of the 1960\u27s, together with a continued high rate of out-migration, gave South Dakota a population loss for the 60\u27s of 2.1%. The 1970\u27s present a different picture. During this decade the birth rate continued at a relatively low level. However, a dramatic reduction in net out-migration during the 70\u27s was sufficient to give South Dakota a population increase of 3.3% in spite of the low fertility. (See more in text

    Population Update Report Number 5

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    South Dakota\u27s population on April 1, 1980, was 690,768. This is an increase of 24,511 people or 3.8% from the 666,257 in 1970. The growth rate of 3.8% for 1970-1980 ranks South Dakota sixth in the rate of increase for seven neighboring states (Table 1). The growth rates of Montana (13%) and especially Wyoming (42%), fourth highest in the nation, are particularly significant in that they are larger than the U.S. total growth of 11%. They reflect a tremendous growth due to utilization of natural resources. The surrounding farm belt states experienced the slower growth rate evident throughout the agriculturally based midwest regio

    Six Districts Begin the Principal Pipeline Initiative

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    This first report of an ongoing evaluation of The Wallace Foundation's Principal Pipeline Initiative describes the six participating school districts' plans and activities during the first year of their grants. The evaluation, conducted by Policy Studies Associates and the RAND Corporation, isintended to inform policy makers and practitioners about the process of carrying out new policies and practices for school leadership and about the results of investments in the Principal Pipeline Initiative. This report is based on collection and analysis of qualitative data, including the districts' proposals, work plans, and progress reports and semi-structured interviews in spring 2012 with 91 administrators employed by districts and their partner institutions. Leaders in all districts report wanting to enlarge their pools of strong applicants for principal positions and to identify and cultivate leadership talent as early as possible in educators' careers.Districts are actively working on allrequired pipeline components: (1) with stakeholder participation, they have developed standards and identified competencies for principals, which they plan to use to guide principal training, hiring, evaluation, and support; (2) they are initiating or strengthening partnerships with university training programs; (3) for hiring, they have standard performance tasks and are developing systems to capture data on candidates' experience; (4) they have diagnostic evaluation tools and are working to build the capacity of principals' supervisors and mentors to support principals' skill development. In addition, all are also bolstering district-run training programs for graduates of university training programs who aspire to become principals

    High-Resolution K' Imaging of the z = 1.786 Radio Galaxy 3C 294

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    We have obtained imaging in the K' band (~I-band rest frame) of the z=1.786 radio galaxy 3C 294 with the 36-element curvature-sensing adaptive optics system Hokupa`a and the Canada-France-Hawaii Telescope. At a resolution of < \~0."15, the galaxy is seen as a group of small but resolved knots distributed over a roughly triangular region ~1."4 across. The interpretation of the structure depends on the location of the nucleus, as indicated by the compact radio core. Its position is uncertain by > ~0."5 (2-sigma) because of uncertainties in the optical astrometry, but our best estimate places it at or near the southern apex of the distribution. If this location is correct, the most likely interpretation is that of a hidden quasar nucleus illuminating dusty infalling dwarf-galaxy-like clumps having characteristic sizes of ~1.5 kpc.Comment: 8 pages. One figure in gif format. Postscript version including fig. (240 kb) available at http://www.ifa.hawaii.edu/~canaguby/preprints.html To appear in ApJ. Letter

    Redundant Arrays of IDE Drives

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    The next generation of high-energy physics experiments is expected to gather prodigious amounts of data. New methods must be developed to handle this data and make analysis at universities possible. We examine some techniques that use recent developments in commodity hardware. We test redundant arrays of integrated drive electronics (IDE) disk drives for use in offline high-energy physics data analysis. IDE redundant array of inexpensive disks (RAID) prices now equal the cost per terabyte of million-dollar tape robots! The arrays can be scaled to sizes affordable to institutions without robots and used when fast random access at low cost is important. We also explore three methods of moving data between sites; internet transfers, hot pluggable IDE disks in FireWire cases, and writable digital video disks (DVD-R).Comment: Submitted to IEEE Transactions On Nuclear Science, for the 2001 IEEE Nuclear Science Symposium and Medical Imaging Conference, 8 pages, 1 figure, uses IEEEtran.cls. Revised March 19, 2002 and published August 200
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