3,933 research outputs found

    Adhesive bonding and the use of corrosion resistant primers

    Get PDF
    The use of an anti-corrosive primer has been shown to be essential to assure survival of a bonded structure in a hostile environment, particularly if a stress is to be applied to the adhesively bonded joint during the environmental exposure. For example, the Lockheed L-1011 TriStar assembly, after exhaustive evaluation tests specifies use of chromate filled inhibitive polysulfide sealants, and use of corrosion inhibiting adhesive primers prior to structural bonding with film adhesive

    Surface-integral expressions for the multipole moments of post-Newtonian sources and the boosted Schwarzschild solution

    Full text link
    New expressions for the multipole moments of an isolated post-Newtonian source, in the form of surface integrals in the outer near-zone, are derived. As an application we compute the ``source'' quadrupole moment of a Schwarzschild solution boosted to uniform velocity, at the third post-Newtonian (3PN) order. We show that the consideration of this boosted Schwarzschild solution (BSS) is enough to uniquely determine one of the ambiguity parameters in the recent computation of the gravitational wave generation by compact binaries at 3PN order: zeta=-7/33. We argue that this value is the only one for which the Poincar\'e invariance of the 3PN wave generation formalism is realized. As a check, we confirm the value of zeta by a different method, based on the far-zone expansion of the BSS at fixed retarded time, and a calculation of the relevant non-linear multipole interactions in the external metric at the 3PN order.Comment: 30 pages, submitted to Classical and Quantum Gravit

    Improved filters for gravitational waves from inspiraling compact binaries

    Get PDF
    The order of the post-Newtonian expansion needed to extract in a reliable and accurate manner the fully general relativistic gravitational wave signal from inspiraling compact binaries is explored. A class of approximate wave forms, called P-approximants, is constructed based on the following two inputs: (a) the introduction of two new energy-type and flux-type functions e(v) and f(v), respectively, (b) the systematic use of the Padé approximation for constructing successive approximants of e(v) and f(v). The new P-approximants are not only more effectual (larger overlaps) and more faithful (smaller biases) than the standard Taylor approximants, but also converge faster and monotonically. The presently available (v/c)^5-accurate post-Newtonian results can be used to construct P-approximate wave forms that provide overlaps with the exact wave form larger than 96.5%, implying that more than 90% of potential events can be detected with the aid of P-approximants as opposed to a mere 10–15 % that would be detectable using standard post-Newtonian approximants

    Gravitational radiation from inspiralling compact binaries completed at the third post-Newtonian order

    Full text link
    The gravitational radiation from point particle binaries is computed at the third post-Newtonian (3PN) approximation of general relativity. Three previously introduced ambiguity parameters, coming from the Hadamard self-field regularization of the 3PN source-type mass quadrupole moment, are consistently determined by means of dimensional regularization, and proved to have the values xi = -9871/9240, kappa = 0 and zeta = -7/33. These results complete the derivation of the general relativistic prediction for compact binary inspiral up to 3.5PN order, and should be of use for searching and deciphering the signals in the current network of gravitational wave detectors.Comment: 4 pages in 2-column format, LaTeX 2e, REVTeX 4, no figur

    Adverse Effects of Cholinesterase Inhibitors in Dementia, According to the Pharmacovigilance Databases of the United-States and Canada.

    Get PDF
    This survey analyzes two national pharmacovigilance databases in order to determine the major adverse reactions observed with the use of cholinesterase inhibitors in dementia. We conducted a statistical analysis of the Food and Drug Administration Adverse Event Reporting System (FAERS) and the Canada Vigilance Adverse Reaction Database (CVARD) concerning the side effects of cholinesterase inhibitors. The statistics calculated for each adverse event were the frequency and the reporting odds ratios (ROR). A total of 9877 and 2247 reports were extracted from the FAERS and CVARD databases, respectively. A disproportionately higher frequency of reports of death as an adverse event for rivastigmine, compared to the other acetylcholinesterase inhibiting drugs, was observed in both the FAERS (ROR = 3.42; CI95% = 2.94-3.98; P<0.0001) and CVARD (ROR = 3.67; CI95% = 1.92-7.00; P = 0.001) databases. While cholinesterase inhibitors remain to be an important therapeutic tool against Alzheimer's disease, the disproportionate prevalence of fatal outcomes with rivastigmine compared with alternatives should be taken into consideration

    PRESSURE BROADENING AND SHIFTING COEFFICIENTS AS TESTS OF H2(D2)-He POTENTIAL ENERGY SURFACES

    No full text
    International audienceWe have calculated the helium-pressure broadening and shifting coefficients of the isotropic Raman Q(1) lines of the fundamental of H 2 and D 2. The quantum dynamical close coupling calculations were performed on five 3-dimensional PESs, namely: the pot3d potential of Bakr et al, 1 the so-called BMP PES, 2 the modified Muchnik and Russek PES, 3 the modified BMP PES, 1 and the Schaefer and Köhler PES. 4 The last one being the oldest one and obtained at the lowest-level of quantum chemical accuracy but has the advantage of covering interactions over a larger intramolecular interval. Moreover, the theoretical values it leads to 5,6,7 are in quite good agreement with experimental pressure broadening and shifting coeffients. 7,8,9,10 By decomposing the kinetic energy dependent pressure broadening cross-sections in an inelastic part and a dephasing one and by also looking at the isotropic contribution of the pressure shifting cross-sections allow us to bring to the fore the main differences that exist between the five PESs we have considered. The modBMP PES has been readily rejected because it is only a slight modification of the original BMP PES. The BMP and modMR PESs lead to thermally averaged values far from the experimental ones. The quantum chemical " state of the art " PES of Bakr et al provides shifting parameters in better agreement than the SK PES with experimental shifts but, the broadening parameters seem to be slightly more accurate with the SK PES. This last point should be confirmed by an accu-

    Measurability of the tidal polarizability of neutron stars in late-inspiral gravitational-wave signals

    Full text link
    The gravitational wave signal from a binary neutron star inspiral contains information on the nuclear equation of state. This information is contained in a combination of the tidal polarizability parameters of the two neutron stars and is clearest in the late inspiral, just before merger. We use the recently defined tidal extension of the effective one-body formalism to construct a controlled analytical description of the frequency-domain phasing of neutron star inspirals up to merger. Exploiting this analytical description we find that the tidal polarizability parameters of neutron stars can be measured by the advanced LIGO-Virgo detector network from gravitational wave signals having a reasonable signal-to-noise ratio of ρ=16\rho=16. This measurability result seems to hold for all the nuclear equations of state leading to a maximum mass larger than 1.97M1.97M_\odot. We also propose a promising new way of extracting information on the nuclear equation of state from a coherent analysis of an ensemble of gravitational wave observations of separate binary merger events.Comment: 28 pages, 6 figures. Submitted to Phys. Rev.
    corecore