1,758 research outputs found

    Computerized conductometric determination of stability constants of complexes of crown ethers with alkali metal salts and with neutral molecules in polar solvents

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    A computerized conductometric procedure for the determination of stability constants of the complexes of crown ethers (15-crown-5, benzo-15-crown-5 and 12-crown-4) with alkali metal salts in polar solvents is described, based on a microcomputer-controlled titration system. For the control of the experiments from software, a modular computer program was written in FORTH computer language. The procedure is especially suitable for the study of 1:2 metal ion/ligand complexes, which occur frequently with the compounds used. For the study of the interaction between crown ethers and neutral molecules, an indirect procedure is outlined

    Gravitational waves from Sco X-1: A comparison of search methods and prospects for detection with advanced detectors

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    The low-mass X-ray binary Scorpius X-1 (Sco X-1) is potentially the most luminous source of continuous gravitational-wave radiation for interferometers such as LIGO and Virgo. For low-mass X-ray binaries this radiation would be sustained by active accretion of matter from its binary companion. With the Advanced Detector Era fast approaching, work is underway to develop an array of robust tools for maximizing the science and detection potential of Sco X-1. We describe the plans and progress of a project designed to compare the numerous independent search algorithms currently available. We employ a mock-data challenge in which the search pipelines are tested for their relative proficiencies in parameter estimation, computational efficiency, robust- ness, and most importantly, search sensitivity. The mock-data challenge data contains an ensemble of 50 Scorpius X-1 (Sco X-1) type signals, simulated within a frequency band of 50-1500 Hz. Simulated detector noise was generated assuming the expected best strain sensitivity of Advanced LIGO and Advanced VIRGO (4×10−244 \times 10^{-24} Hz−1/2^{-1/2}). A distribution of signal amplitudes was then chosen so as to allow a useful comparison of search methodologies. A factor of 2 in strain separates the quietest detected signal, at 6.8×10−266.8 \times 10^{-26} strain, from the torque-balance limit at a spin frequency of 300 Hz, although this limit could range from 1.2×10−251.2 \times 10^{-25} (25 Hz) to 2.2×10−262.2 \times 10^{-26} (750 Hz) depending on the unknown frequency of Sco X-1. With future improvements to the search algorithms and using advanced detector data, our expectations for probing below the theoretical torque-balance strain limit are optimistic.Comment: 33 pages, 11 figure

    The 4^4He(e,eâ€Čp)(e,e'p) Cross Section at Large Missing Energy

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    The (e,eâ€Čp)(e,e'p) reaction on 4He^{4}{He} nuclei was studied in kinematics designed to emphasize effects of nuclear short-range correlations. The measured cross sections display a peak in the kinematical regions where two-nucleon processes are expected to dominate. Theoretical models incorporating short-range correlation effects agree reasonably with the data.Comment: 4 pages LaTeX, using espcrc1.sty and wrapfig.sty (included), two figures. Talk presented by J. Templon at the 15th Int. Conf. on Few-Body Problems in Physics, Groningen, The Netherlands, 22-26 July, 199

    Inclusive Electron Scattering from Nuclei at x≃1x \simeq 1

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    The inclusive A(e,e') cross section for x≃1x \simeq 1 was measured on 2^2H, C, Fe, and Au for momentum transfers Q2Q^2 from 1-7 (GeV/c)2^2. The scaling behavior of the data was examined in the region of transition from y-scaling to x-scaling. Throughout this transitional region, the data exhibit Ο\xi-scaling, reminiscent of the Bloom-Gilman duality seen in free nucleon scattering.Comment: 4 pages, RevTeX; 4 figures (postscript in .tar.Z file

    Tensor Analyzing Powers for Quasi-Elastic Electron Scattering from Deuterium

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    We report on a first measurement of tensor analyzing powers in quasi-elastic electron-deuteron scattering at an average three-momentum transfer of 1.7 fm−1^{-1}. Data sensitive to the spin-dependent nucleon density in the deuteron were obtained for missing momenta up to 150 MeV/cc with a tensor polarized 2^2H target internal to an electron storage ring. The data are well described by a calculation that includes the effects of final-state interaction, meson-exchange and isobar currents, and leading-order relativistic contributions.Comment: 4 pages, 3 figure

    General Survey of Polarization Observables in Deuteron Electrodisintegration

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    Polarization observables in inclusive and exclusive electrodisintegration of the deuteron using a polarized beam and an oriented target are systematically surveyed using the standard nonrelativistic framework of nuclear theory but with leading order relativistic contributions included. The structure functions and the asymmetries corresponding to the various nucleon polarization components are studied in a variety of kinematic regions with respect to their sensitivity to realistic NNNN-potential models, to subnuclear degrees of freedom in terms of meson exchange currents, isobar configurations and to relativistic effects in different kinematical regions, serving as a benchmark for a test of present standard nuclear theory with effective degrees of freedom.Comment: 56 pages, 32 figures, revtex

    Enabling a healthy future for everyone: Important research topics on behalf of an advisory board of inhabitants

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    Experiential knowledge is crucial to enable healthy living, and reduce health inequalities. An advisory board of inhabitants, installed at the chairgroup Consumption and Healthy Lifestyles at Wageningen University and Research presents important topics for future research from their perspective. These research topics relate to (1) the complexity of the system; (2) the interaction between mental health and healthy living; (3) the living environment. Furthermore, relevant similarities and differences appear from a comparison of these topics with the “Kennisagenda Samen Gezond Leven”, a knowledge agenda issued recently by scientific experts, policymakers and professionals

    Relativistic effects and two-body currents in 2H(e⃗,eâ€Čp)n^{2}H(\vec{e},e^{\prime}p)n using out-of-plane detection

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    Measurements of the 2H(e⃗,eâ€Čp)n{^2}H(\vec{e},e^{\prime}p)n reaction were performed using an 800-MeV polarized electron beam at the MIT-Bates Linear Accelerator and with the out-of-plane magnetic spectrometers (OOPS). The longitudinal-transverse, fLTf_{LT} and fLTâ€Čf_{LT}^{\prime}, and the transverse-transverse, fTTf_{TT}, interference responses at a missing momentum of 210 MeV/c were simultaneously extracted in the dip region at Q2^2=0.15 (GeV/c)2^2. On comparison to models of deuteron electrodisintegration, the data clearly reveal strong effects of relativity and final-state interactions, and the importance of the two-body meson-exchange currents and isobar configurations. We demonstrate that these effects can be disentangled and studied by extracting the interference response functions using the novel out-of-plane technique.Comment: 4 pages, 4 figures, and submitted to PRL for publicatio

    Spin-Momentum Correlations in Quasi-Elastic Electron Scattering from Deuterium

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    We report on a measurement of spin-momentum correlations in quasi-elastic scattering of longitudinally polarized electrons with an energy of 720 MeV from vector-polarized deuterium. The spin correlation parameter AedVA^V_{ed} was measured for the 2H⃗(e⃗,eâ€Čp)n^2 \vec{\rm H}(\vec e,e^\prime p)n reaction for missing momenta up to 350 MeV/cc at a four-momentum transfer squared of 0.21 (GeV/c)2^2. The data give detailed information about the spin structure of the deuteron, and are in good agreement with the predictions of microscopic calculations based on realistic nucleon-nucleon potentials and including various spin-dependent reaction mechanism effects. The experiment demonstrates in a most direct manner the effects of the D-state in the deuteron ground-state wave function and shows the importance of isobar configurations for this reaction.Comment: 4 pages, 3 figures, submitted to Phys. Rev. Lett. for publicatio
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