1,157 research outputs found

    Preparation, characterization, physical testing and performance of fluorocarbon membranes and separators

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    The direct fluorination method of converting carefully selected hydrocarbon substrates to fluorinated membranes was successfully applied to produce promising, novel membranes for electrochemical devices. A family of polymer blends was identified which permits wide latitude in the concentration of both crosslinks and carboxyl groups in hydrocarbon membranes. These membranes were successfully fluorinated and are potentially competitive with commercial membranes in performance, and potentially much cheaper in price

    Preparation, characterization, physical testing and performance of flurocarbon membranes and separators

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    The direct fluorination method of converting carefully selected hydrocarbon substrates to fluorinated membranes was successfully applied to produce promising, novel membranes for electrochemical devices. A family of polymer blends was identified which permits wide latitude in the concentration of both crosslinks and carboxyl groups in hydrocarbon membranes. The membranes of paragraph two were successfully fluorinated

    Fractional Curve Flows and Solitonic Hierarchies in Gravity and Geometric Mechanics

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    Methods from the geometry of nonholonomic manifolds and Lagrange-Finsler spaces are applied in fractional calculus with Caputo derivatives and for elaborating models of fractional gravity and fractional Lagrange mechanics. The geometric data for such models are encoded into (fractional) bi-Hamiltonian structures and associated solitonic hierarchies. The constructions yield horizontal/vertical pairs of fractional vector sine-Gordon equations and fractional vector mKdV equations when the hierarchies for corresponding curve fractional flows are described in explicit forms by fractional wave maps and analogs of Schrodinger maps.Comment: latex2e, 11pt, 21 pages; the variant accepted to J. Math. Phys.; new and up--dated reference

    Lax Tensors, Killing Tensors and Geometric Duality

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    The solution of the Lax tensor equations in the case Lαβγ=LβαγL_{\alpha\beta\gamma}=-L_{\beta\alpha\gamma} was analyzed. The Lax tensors on the dual metrics were investigated. We classified all two dimensional metrics having the symmetric Lax tensor LαβγL_{\alpha\beta\gamma}. The Lax tensors of the flat space, Rindler system and its dual were found.Comment: 9 pages LATE

    Extraction of reliable information from time-domain pressure and flow signals measured by means of forced oscillation techniques

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    This paper aims to give a proof-of-concept for the possible application of the forced oscillation lung function test to assess the viscoelastic properties of the airways and tissue. In particular, a novel signal processing algorithm is employed on non-stationary, noisy, (relatively) short time series of respiratory pressure and flow signals. This novel technique is employed to filter the useful information from the signals acquired under two measurement conditions: pseudo-functional residual capacity (PFRC) and pseudo-total lung capacity (PTLC). The PFRC is the measurement performed at lowest lung volume with maximum deflation, and the PTLC is measurement performed at the maximum lung volume under maximum inflation. The results suggest that the proposed technique is able to extract information on the viscoelastic properties of the lung tissue at a macroscopic level. The conclusion of this preliminary study is that the proposed combination of signal processing method and lung function test is suited to be employed on a large database in order to deliver reference values and perform further statistical analysis

    Note on counterterms in asymptotically flat spacetimes

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    We consider in more detail the covariant counterterm proposed by Mann and Marolf in asymptotically flat spacetimes. With an eye to specific practical computations using this counterterm, we present explicit expressions in general dd dimensions that can be used in the so-called `cylindrical cut-off' to compute the action and the associated conserved quantities for an asymptotically flat spacetime. As applications, we show how to compute the action and the conserved quantities for the NUT-charged spacetime and for the Kerr black hole in four dimensions.Comment: 13 pages, v. 2 added reference

    The burden of clostridium difficile infection in patients with liver cirrhosis

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    Clostridium Difficile Infection (CDI) has registered a dramatically increasing incidence in the general population over the past decades. Nowadays, Clostridium Difficile is the leading cause of hospital-acquired diarrhea in Europe and North America. Liver cirrhosis is the final stage of any chronic liver disease (CLD). The most common causes are chronic hepatitis C or B and viral co-infections, alcohol misuse, and nonalcoholic fatty liver disease (NAFLD). CLD and cirrhosis are listed among the ten leading causes of death in the US. Cirrhosis due to any etiology disrupts the homeostatic role of the liver in the body. Cirrhosis-associated immune dysfunction (CAID) leads to alterations in both inherited and acquired systemic and local liver immunity. CAID is caused by increased systemic inflammation and immunodeficiency and it is responsible for 30% of mortality rates all over the world. Clostridium Difficile infection frequently affects patients suffering from liver cirrhosis because of the high number of prolonged hospitalizations, regular use of antibiotics for the prevention or treatment of SBP, proton pump inhibitor (PPI) use, and an overall immunocompromised state. Clostridium Difficile is a Gram-positive bacterium responsible for the high morbidity and mortality rates in patients with cirrhosis, with an essential increase in a 30-day mortality

    Vortex stability in nearly two-dimensional Bose-Einstein condensates with attraction

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    We perform accurate investigation of stability of localized vortices in an effectively two-dimensional ("pancake-shaped") trapped BEC with negative scattering length. The analysis combines computation of the stability eigenvalues and direct simulations. The states with vorticity S=1 are stable in a third of their existence region, 0<N<(1/3)Nmax(S=1)0<N<(1/3)N_{\max}^{(S=1)}, where NN is the number of atoms, and Nmax(S=1)N_{\max}^{(S=1)} is the corresponding collapse threshold. Stable vortices easily self-trap from arbitrary initial configurations with embedded vorticity. In an adjacent interval, (1/3)Nmax(S=1)<N<(1/3)N_{\max }^{(S=1)}<N< 0.43Nmax(S=1)\allowbreak 0.43N_{\max}^{(S=1)}, the unstable vortex periodically splits in two fragments and recombines. At N>N> 0.43Nmax(S=1)\allowbreak 0.43N_{\max}^{(S=1)}, the fragments do not recombine, as each one collapses by itself. The results are compared with those in the full 3D Gross-Pitaevskii equation. In a moderately anisotropic 3D configuration, with the aspect ratio 10\sqrt{10}, the stability interval of the S=1 vortices occupies 40\approx 40% of their existence region, hence the 2D limit provides for a reasonable approximation in this case. For the isotropic 3D configuration, the stability interval expands to 65% of the existence domain. Overall, the vorticity heightens the actual collapse threshold by a factor of up to 2. All vortices with S2S\geq 2 are unstable.Comment: 21 pages, 8 figures, to appear in Physical Review
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