43 research outputs found

    Probing crystallisation of a fluoro-apatite - mullite system using neutron diffraction

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    Real-time small angle neutron scattering and wide angle neutron scattering studies were undertaken concurrently on a glass ionomer of nominal composition 4.5(SiO2)-3(Al2O3)-1.5(P2O5)-3(CaO)-2(CaF2). Neutron studies were conducted as a function of temperature to investigate the crystallisation process. No amorphous phase separation was observed at room temperature and the onset of crystallisation was found to occur at 650°C, which is 90°C lower than previously reported. The first crystalline phase observed corresponded to fluorapatite; it was only upon further heating was the mullite phase became present. The crystallite size at 650°C was found to be ~115Å and the result was consistent across all measurements

    Critical Hysteresis from Random Anisotropy

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    Critical hysteresis in ferromagnets is investigated through a NN-component spin model with random anisotropies, more prevalent experimentally than the random fields used in most theoretical studies. Metastability, and the tensorial nature of anisotropy, dictate its physics. Generically, random field Ising criticality occurs, but other universality classes exist. In particular, proximity to O(N)\mathcal{O}(N) criticality may explain the discrepancy between experiment and earlier theories. The uniaxial anisotropy constant, which can be controlled in magnetostrictive materials by an applied stress, emerges as a natural tuning parameter.Comment: four pages, revtex4; minor corrections in the text and typos corrected (published version

    MTDATA and the prediction of phase equilibria in oxide systems : 30 years of industrial collaboration

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    This paper gives an introduction to MTDATA, Phase Equilibrium Software from the National Physical Laboratory (NPL), and describes the latest advances in the development of a comprehensive database of thermodynamic parameters to underpin calculations of phase equilibria in large oxide, sulfide, and fluoride systems of industrial interest. The database, MTOX, has been developed over a period of thirty years based upon modeling work at NPL and funded by industrial partners in a project co-ordinated by Mineral Industry Research Organisation. Applications drawn from the fields of modern copper scrap smelting, high-temperature behavior of basic oxygen steelmaking slags, flash smelting of nickel, electric furnace smelting of ilmenite, and production of pure TiO2via a low-temperature molten salt route are discussed along with calculations to assess the impact of impurities on the uncertainty of fixed points used to realize the SI unit of temperature, the kelvin

    Erratum to “Structure of tin phosphate glasses by neutron and X-ray diffraction” [Journal of Non crystalline solids:X 2C (2019) 100017]

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    The publisher regrets the following conflict of interest text was not published. • All the authors listed in this article have made Substantial contributions to the conception or design of the work; or the acquisition, analysis, or interpretation of data for the work; AND drafting the work or revising it critically for important intellectual content; AND Final approval of the version to be published. • I also undertake that the article represents valid work. Neither this article nor any part of it has been copied or plagiarized from other works. • That the article has not been published so far OR communicated OR in simultaneous consideration to some other journal. • I also undertake that the authors have disclosed all potential conflict of interests associated with the work. The publisher would like to apologize for any inconvenience caused

    A NEUTRON DIFFRACTION INVESTIGATION OF THE ATOMIC AND MAGNETIC STRUCTURE OF AMORPHOUS Dy7Ni3

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    La structure atomique et magnétique de Dy7 Ni3, amorphe a été étudiée en diffraction neutronique à partir d'une méthode de double substitution isotopique qui s'est avérée extrêmement puissante.The atomic and magnetic structure of melt-spun amorphous Dy7Ni3 is being studied using the neutron diffraction double-null isotopic substitution technique. It is concluded that the double-null technique is a very powerful method for studying the atomic and magnetic structure of appropriate binary amorphous alloys
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