2,761 research outputs found

    High contrast Mach-Zehnder lithium atom interferometer in the Bragg regime

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    We have constructed an atom interferometer of the Mach-Zehnder type, operating with a supersonic beam of lithium. Atom diffraction uses Bragg diffraction on laser standing waves. With first order diffraction, our apparatus has given a large signal and a very good fringe contrast (74%), which we believe to be the highest ever observed with atom interferometers. This apparatus will be applied to high sensitivity measurementsComment: 6 pages, 3 figures, accepted by Appl. Phys.

    Simulation of Green Water Loading Using the Navier-Stokes Equations

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    Simulation of Green Water Loading Using the Navier-Stokes Equations

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    Simulation of Green Water Loading Using the Navier-Stokes Equations

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    Simulating viscous flows with a free surface causes special difficulties, since its position will change continuously. Therefore, besides solving the Navier-Stokes equations, the position of the free surface must be determined every time step. In the present method, the Navier-Stokes equations are solved on a three-dimensional Cartesian grid. A Volume-of-Fluid function is used for the position of the fluid. Since the method is able to handle arbitrary forms of the geometry, many types of industrial flow problems can be simulated. In this paper the problem of green water loading on the foredeck of a ship is discussed and a comparison is made with experimental results. Waterheights, pressures and water contours are produced and compared with model tests. Also forces on different structures placed on the deck are compared and analyzed

    Simulation of Green Water Loading Using the Navier-Stokes Equations

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    Poly[[tetra­kis­(μ2-pyrazine N,N′-dioxide-κ2 O:O′)holmium(III)] tris­(perchlorate)]

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    The title three-dimensional coordination network, {[Ho(C4H4N2O2)4](ClO4)3}n, is isostructural to that of other lanthanides. The Ho+3 cation lies on a fourfold roto-inversion axis. It is coordinated in a distorted square anti-prismatic fashion by eight O atoms from bridging pyrazine N,N′-dioxide ligands. There are two unique pyrazine N,N′-dioxide ligands. One ring is located around an inversion center, and there is a a twofold rotation axis at the center of the other ring. There are also two unique perchlorate anions. One is centered on a twofold rotation axis and the other on a fourfold roto-inversion axis. The perchlorate anions are located in channels that run perpendicular to (001) (110) and inter­act with the coordination network through C—H⋯O hydrogen bonds

    Management of von Willebrand disease type 3 during pregnancy - 2 cases reports.

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    BACKGROUND: von Willebrand disease type 3, is an extremely rare condition. It can be severe and potentially life-threatening, particularly in pregnant women during labor and subsequently during early puerperium. Due to its rarity, there is no optimal treatment/management during pregnancy. CASE: We describe two cases of pregnant women with von Willebrand disease type 3, and its successful surveillance and treatment with Haemate P FVIII (human plasma-derived von Willebrand Factor-ristocetin co-factor associated with human coagulation factor VIII), during pregnancy, partum and puerperium. CONCLUSIONS: Daily prophylaxis with Haemate P FVIII in women with von Willebrand disease type 3, starting 2 hours before caesarean section until the 7th day of puerperium, associated with close analytical and clinical surveillance seems to be a safe clinical option
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