Digital Filtering Approach to Fast Simulation for Interferometric Gravitational Wave Detectors of Ring-Cavity Sagnac Topology

A digital filtering approach to fast simulation for interferometric gravitational wave detectors of Michelson topology involving dynamical coupled cavities was developed in a recent paper. The present paper describes its application to detectors which might be of Sagnac topology with ring-cavities in arms and thus would be characterised by a different and more complicated nature of coupling among fields in various constituent cavities. The simulation results show that digital filtering approach is successful in developing a fast and reasonably accurate algorithm for the computation of dynamical evolution of fields in such a detector.     

Expanding the tools available for direct ortho cupration--targeting lithium phosphidocuprates

Reaction of in situ generated lithium phosphides with 0.5 eq. Cu(I) is employed as a means of targeting lithium phosphidocuprates of either Gilman- or Lipshutz-type formulation--e.g., (R(2)P)(2)CuLi·n(LiX) (n = 0, 1). For R = Ph, X = CN in toluene followed by thf or R = Ph, X = I in thf/toluene an unexpected product results. [(Ph(2)P)(6)Cu(4)][Li·4thf](2)1 reveals an ion-separated structure in the solid state, with solvated lithium cations countering the charge on an adamantyl dianion [(Ph(2)P)(6)Cu(4)](2-). Deployment of R = Ph, X = CN in thf affords a novel network based on the dimer of Ph(2)PCu(CN)Li·2thf 2 with trianions based on 6-membered (PCu)(3) rings acting as nodes in the supramolecular array and solvated alkali metal counter-ions completing the linkers. Cy(2)PLi (Cy = cyclohexyl) has been reacted with CuCN in thf/toluene to yield Gilman-type lithium bis(phosphido)cuprate (Cy(2)P)(2)CuLi·2thf 3 by the exclusion of in situ generated LiCN. A polymer is noted in the solid state.     

Upper limits on a stochastic background of gravitational waves

The Laser Interferometer Gravitational-Wave Observatory has performed a third science run with much improved sensitivities of all three interferometers. We present an analysis of approximately 200 hours of data acquired during this run, used to search for a stochastic background of gravitational radiation. We place upper bounds on the energy density stored as gravitational radiation for three different spectral power laws. For the flat spectrum, our limit of omega0 < 8.4 x 10(-4) in the 69-156 Hz band is approximately 10(5) times lower than the previous result in this frequency range.     

Lock acquisition of a gravitational-wave interferometer

Interferometric gravitational-wave detectors, such as the Laser Interferometer Gravitational Wave Observatory (LIGO) detectors currently under construction, are based on kilometer-scale Michelson interferometers, with sensitivity that is enhanced by addition of multiple coupled optical resonators. Reducing the relative optic motions to bring the system to the resonant operating point is a significant challenge. We present a new approach to lock acquisition, used to lock a LIGO interferometer, whereby the sensor transformation matrix is dynamically calculated to sequentially bring the cavities into resonance.     

Recalculation of monomer reactivity considering the effect of monomer partitioning in microemulsion

From the copolymerisation data for the microemulsion polymerisation of both partially water soluble monomers ethylacrylate (EA)-methylmethacrylate (MMA) the concentration of the monomer at the polymerisation loci was calculated. While the reported copolymerisation data for the microemulsion copolymerisation of styrene (Sty)-methylacrylate (MA), monomer pair with different solubility and polarity and Sty-butylacrylate (BA), monomer pair with similar solubility and different polarity was used to calculate the monomer concentration at loci. It was inferred from the non-constancy of f^′_A/f_A and f^′_B/f_B ratio that the preferential site of polymerisation might be the emulsifier layer in case of Sty-MA and Sty-BA. While, based on the monomer fraction in the copolymer and the constancy of f^′_A/f_A and f^′_B/f_B it was concluded that microemulsion polymerisation for monomer pair EA-MMA, having similar solubility and polarity, conforms more to bulk polymerisation, where there is no preferential site of polymerisation. The loci concentration rather than feed value was used to recalculate the reactivity at the site of polymerisation. Also the loci concentration was calculated assuming their sum at the polymerisation site equal to unity.     

A facile green synthesis of silver nanoparticle-decorated hydroxyapatite for efficient catalytic activity towards 4-nitrophenol reduction

Research on Chemical Intermediates - Silver nanoparticles (AgNPs) were gradually grown on a hydroxyapatite surface via a green self-reducing approach. Hydroxyapatite (HAP) was functionalized by...     

New Synthesis of 1-Aryl-4-(4-hydroxy-3,5-diiodo-α-methylbenzylidene)-2-phenylimidazol-5-ones

Some new 1-aryl-4-(4-hydroxy-3,5-diiodo--methylbenzylidene)-2-phenylimidazol-5-ones were prepared by treating the mixture of an analogous 5-oxazolone derivative with aromatic and substituted aromatic amines in the presence of Zeolite (Y-H) catalyst.