4,656 research outputs found

    Accurate and efficient gravitational waveforms for certain galactic compact binaries

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    Stellar-mass compact binaries in eccentric orbits are almost guaranteed sources of gravitational waves for Laser Interferometer Space Antenna. We present a prescription to compute accurate and efficient gravitational-wave polarizations associated with bound compact binaries of arbitrary eccentricity and mass ratio moving in slowly precessing orbits. We compare our approach with those existing in the literature and present its advantages.Comment: 10 pages, 7 figures, to be published in MNRA

    Numerical Analyses of Weakly Nonlinear Velocity-Density Coupling

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    We study evolution of various statistical quantities of smoothed cosmic density and velocity fields using N-body simulations. The parameter C≡/()C\equiv /( ) characterizes nonlinear coupling of these two fields and determines behavior of bulk velocity dispersion as a function of local density contrast. It is found that this parameter depends strongly on the smoothing scale even in quasi-linear regimes where the skewness parameter S3S_3 is nearly constant and close to the predicted value by the second-order perturbation theory. We also analyze weakly nonlinear effects caused by an adaptive smoothing known as the gather approach.Comment: 22 pages, 4 figures, to appear in ApJ (558, Sep 10

    Apollo cryogenic integrated systems program

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    The integrated systems program is capable of simulating both nominal and anomalous operation of the Apollo cryogenics storage system (CSS). Two versions of the program exist; one for the Apollo 14 configuration and the other for J Type Mission configurations. The program consists of two mathematical models which are dynamically coupled. A model of the CSS components and lines determines the oxygen and hydrogen flowrate from each storage tank given the tank pressures and temperatures, and the electrical power subsystem and environmental control subsystem flow demands. Temperatures and pressures throughout the components and lines are also determined. A model of the CSS tankage determines the pressure and temperatures in the tanks given the flowrate from each tank and the thermal environment. The model accounts for tank stretch and includes simplified oxygen tank heater and stratification routines. The program is currently operational on the Univac 1108 computer

    Unbinding Transition Induced by Osmotic Pressure in Relation to Unilamellar Vesicle Formation

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    Small-angle X-ray scattering and phase-contrast microscopy experiments were performed to investigate the effect of the osmotic pressure on vesicle formation in a dioleoylphosphatidylcholine (DOPC)/water/NaI system. Multi-lamellar vesicles were formed when a pure lipid film was hydrated with an aqueous solution of NaI. On the other hand, uni-lamellar vesicles (ULVs) were formed when a lipid film mixed with an enough amount of NaI was hydrated. To confirm the effect of the osmotic pressure due to NaI, a free-energy calculation was performed. This result showed that the osmotic pressure induced an unbinding transition on the hydration process, which resulted in ULV formation

    Signature of the Overhauser field on the coherent spin dynamics of donor-bound electron in a single CdTe quantum well

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    We have studied the coherent spin dynamics in an oblique magnetic field of electrons localized on donors and placed in the middle of a single CdTe quantum well, by using a time-resolved optical technique: the photo-induced Faraday rotation. We showed that this dynamics is affected by a weak Overhauser field created via the hyperfine interaction of optically spin-polarized donor-bound electrons with the surrounding nuclear isotopes carrying non-zero spins. We have measured this nuclear field, which is on the order of a few mT and can reach a maximum experimental value of 9.4 mT. This value represents 13 % of the maximal nuclear polarization, and corresponds also to 13 % of maximal electronic polarization.Comment: 15 pages, 4 figure
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