1,313 research outputs found

    Do the new exchange rate indexes offer better answers to old questions?

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    Foreign exchange rates ; Dollar, American ; International trade

    Selecting an intermediate target for monetary policy

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    Monetary policy ; Money supply

    Decoupling of epitaxial graphene via gold intercalation probed by dispersive Raman spectroscopy

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    Signatures of a superlattice structure composed of a quasi periodic arrangement of atomic gold clusters below an epitaxied graphene (EG) layer are examined using dispersive Raman spectroscopy. The gold-graphene system exhibits a laser excitation energy dependant red shift of the 2D mode as compared to pristine epitaxial graphene. The phonon dispersions in both the systems are mapped using the experimentally observed Raman signatures and a third-nearest neighbour tight binding electronic band structure model. Our results reveal that the observed excitation dependent Raman red shift in gold EG primarily arise from the modifications of the phonon dispersion in gold-graphene and shows that the extent of decoupling of graphene from the underlying SiC substrate can be monitored from the dispersive nature of the Raman 2D modes. The intercalated gold atoms restore the phonon band structure of epitaxial graphene towards free standing graphene

    Unusual magnetic-field dependence of partially frustrated triangular ordering in manganese tricyanomethanide

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    Manganese tricyanomethanide, Mn[C(CN)3]2, consists of two interpenetrating three-dimensional rutile-like networks. In each network, the tridentate C(CN)3- anion gives rise to superexchange interactions between the Mn2+ ions (S=5/2) that can be mapped onto the "row model" for partially frustrated triangular magnets. We present heat capacity measurements that reveal a phase transition at T_N = 1.18K, indicative of magnetic ordering. The zero-field magnetically ordered structure was solved from neutron powder diffraction data taken between 0.04 and 1.2 K. It consists of an incommensurate spiral with a temperature independent propagation vector Q=(2Q 0 0)=(+/-0.622 0 0), where different signs relate to the two different networks. This corresponds to (+/-0.311 +/-0.311 0) in a quasi-hexagonal representation. The ordered moment mu=3.3mu_B is about 2/3 of the full Mn2+ moment. From the values of T_N and Q, the exchange parameters J/k = 0.15 K and J'/J = 0.749 are estimated. The magnetic-field dependence of the intensity of the Bragg reflection, measured for external fields H||Q, indicates the presence of three different magnetic phases. We associate them with the incommensurate spiral (H < 13.5 kOe), an intermediate phase (13.5 kOe 16 kOe) proposed for related compounds. For increasing fields, Q continuously approaches the value 1/3, corresponding to the commensurate magnetic structure of the fully frustrated triangular lattice. This value is reached at H_c = 19 kOe. At this point, the field-dependence reverses and Q adopts a value of 0.327 at 26 kOe, the highest field applied in the experiment. Except for H_c, the magnetic ordering is incommensurate in all three magnetic phases of Mn[C(CN)3]2.Comment: accepted for publication in J. Phys.: Condens. Matte

    Continuous Commissioning of a Central Chilled Water & Hot Water System

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    A central chilled water / hot water system provides cooling / heating energy from central utility plants to multiple customers (buildings) through campus distribution loops. To effectively transport the chilled water and hot water to the buildings and control the flow, several types of bypass schemes are used, including air handling unit coil bypass, pump bypass, building loop bypass, distribution loop bypass, and central utility plant decoupling. Most of the bypass schemes are designed to provide comfort to each building without regard for the loop pumping requirements. Continuous Commissioning of the building and campus loops is necessary to ensure adequate water flow to each building and reduce the overall pumping energy required for both the campus loops and the building loops. Some optimization of the plant chiller 1 boiler operation is also necessary and beneficial. In general, through Continuous Commissioning, chilled water and hot water loop temperature differences will be improved, leading to reduced chilled water and hot water flow rates. This will save pumping energy and improve chiller/boiler efficiancy
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