2,657 research outputs found

    Aerodynamic investigation of an air-cooled axial-flow turbine. Part 2: Rotor blade tip-clearance effects on overall turbine performance and internal gas flow conditions: Experimental results and prediction methods

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    Total turbine blade performance was investigated while changing the blade tip clearance in three ways. The internal flow at the moving blade outlet point was measured. Experimental results were compared with various theoretical methods. Increased blade clearance leads to decreased turbine efficiency

    Pupillometry, a bioengineering overview

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    The pupillary control system is examined using a microprocessor based integrative pupillometer. The real time software functions of the microprocessor include: data collection, stimulus generation and area to diameter conversion. Results of an analysis of linear and nonlinear phenomena are presented

    Single-crystal growth of underdoped Bi-2223

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    To investigate the origin of the enhanced Tc ({\approx} 110 K) of the trilayer cuprate superconductor Bi2Sr2Ca2Cu3O10+{\delta} (Bi-2223), its underdoped single crystals are a critical requirement. Here, we demonstrate the first successful in-plane resistivity measurements of heavily underdoped Bi-2223 (zero-resistivity temperatures {\approx} 20~35 K). Detailed crystal growth methods, the annealing process, as well as X-ray diffraction (XRD) and magnetic susceptibility measurement results are also reported.Comment: 4 pages, 4 figures, 27th International Symposium on Superconductivity, ISS 2014, to appear in Physics Procedi

    Effect of Sulfur on Siderophile Element Partitioning Between Olivine and Martian Primary Melt

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    Since olivine is a common early crystallizing phase in basaltic magmas that have produced planetary and asteroidal crusts, a number of experimental studies have investigated elemental partitioning between olivine and silicate melt [e.g., 1, 2, 3]. In particular, olivine/melt partition coefficients of Ni and Co (DNi and DCo) have been intensively studied because these elements are preferentially partitioned into olivine and thus provide a uniquely useful insight into the basalt petrogenesis [e.g., 4, 5]. However, none of these experimental studies are consistent with incompatible signatures of Co [e.g., 6, 7, 8] and Ni [7] in olivines from Martian meteorites. Chemical analyses of undegassed MORB samples suggest that S dissolved in silicate melts can reduce DNi up to 50 % compared to S-free experimental systems [9]. High S solubility (up to 4000 ppm) for primitive shergottite melts [10] implies that S might have significantly influenced the Ni and Co partitioning into shergottite olivines. This study conducts melting experiments on Martian magmatic conditions to investigate the effect of S on the partitioning of siderophile elements between olivine and Martian primary melt

    Improvement of Production Rate of YBCO Coated Conductors Fabricated by TFA-MOD Method

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    AbstractThe metal-organic deposition (MOD) method using trifluoroacetate (TFA) salts is considered to be an effective method for inexpensively fabricating YBa2Cu3O7-y (YBCO) coated conductors with high critical current density property. The long-length TFA-MOD YBCO coated conductors have been fabricated by multi-turn reel-to-reel system. Increasing the thickness per single coating in the multi-turn reel-to-reel system is a cost-effective technique for fabrication of the precursor films in the calcination process since it reduces the number of coatings and shortens the processing time. In this work, we have developed a new starting solution consisting of non-fluorine salts of yttrium propionate and copper 2-ethylhexanoate with focusing on increasing the thickness per single coating for a high-rate fabrication of the YBCO coated conductors by the TFA-MOD method. The critical thickness per single coating of the precursor film fabricated from the new starting solution was improved to 0.44μm/coat. Furthermore, the addition of diacetoneacrylamide in the new starting solution increased the critical thickness per single coating to 0.79μm/coat. High critical current of 791 A/cm-width with high critical current density of 2.7 MA/cm2 was obtained using the new starting solution with diacetoneacrylamide at the thickness per single coating of 0.49μm/coat

    Proximity to Fermi-surface topological change in superconducting LaO0.54F0.46BiS2

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    The electronic structure of nearly optimally-doped novel superconductor LaO1−x_{1-x}Fx_xBiS2_2 (x{\it x} = 0.46) was investigated using angle-resolved photoemission spectroscopy (ARPES). We clearly observed band dispersions from 2 to 6 eV binding energy and near the Fermi level (EF{\it E}_{\rm F}), which are well reproduced by first principles calculations when the spin-orbit coupling is taken into account. The ARPES intensity map near EF{\it E}_{\rm F} shows a square-like distribution around the Γ\Gamma(Z) point in addition to electronlike Fermi surface (FS) sheets around the X(R) point, indicating that FS of LaO0.54_{0.54}F0.46_{0.46}BiS2_2 is in close proximity to the theoretically-predicted topological change.Comment: 6 pages, 3 figures, + supplemental materia
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