18,160 research outputs found

    Indexed keyed connection Patent

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    Standard coupling design for mass productio

    Satellite Power System. Concept development and evaluation program, volume 6: Construction and operations

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    The construction, operation, and maintenance requirements for a solar power satellite, including the space and ground systems, are reviewed. The basic construction guidelines are explained, and construction location options are discussed. The space construction tasks, equipment, and base configurations are discussed together with the operations required to place a solar power satellite in geosynchronous orbit. A rectenna construction technique is explained, and operation with the grid is defined. Maintenance requirements are summarized for the entire system. Key technology issues required for solar power satellite construction operations are defined

    Decuplet baryon magnetic moments in a QCD-based quark model beyond quenched approximation

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    We study the decuplet baryon magnetic moments in a QCD-based quark model beyond quenched approximation. Our approach for unquenching the theory is based on the heavy baryon perturbation theory in which the axial couplings for baryon - meson and the meson-meson-photon couplings from the chiral perturbation theory are used together with the QM moment couplings. It also involves the introduction of a form factor characterizing the structure of baryons considered as composite particles. Using the parameters obtained from fitting the octet baryon magnetic moments, we predict the decuplet baryon magnetic moments. The Ω−\Omega^- magnetic moment is found to be in good agreement with experiment: ΌΩ−\mu_{\Omega^-} is predicted to be −1.97ÎŒN-1.97 \mu_N compared to the experimental result of (−-2.02 ±\pm 0.05) ÎŒN\mu_N.Comment: 19 pages, 2 figure

    1/N_c Expansion of the Heavy Baryon Isgur-Wise Functions

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    The 1/N_c expansion of the heavy baryon Isgur-Wise functions is discussed. Because of the contracted SU(2N_f) light quark spin-flavor symmetry, the universality relations among the Isgur-Wise functions of \Lambda_b to \Lambda_c and \Sigma_b^{(*)} to \Sigma_c^{(*)} are valid up to the order of 1/N_c^2.Comment: 7 pages, latex, no figures, to appear in Phys. Rev.

    The Decuplet Revisited in χ\chiPT

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    The paper deals with two issues. First, we explore the quantitiative importance of higher multiplets for properties of the Δ\Delta decuplet in chiral perturbation theory. In particular, it is found that the lowest order one--loop contributions from the Roper octet to the decuplet masses and magnetic moments are substantial. The relevance of these results to the chiral expansion in general is discussed. The exact values of the magnetic moments depend upon delicate cancellations involving ill--determined coupling constants. Second, we present new relations between the magnetic moments of the Δ\Delta decuplet that are independent of all couplings. They are exact at the order of the chiral expansion used in this paper.Comment: 7 pages of double column revtex, no figure

    Deep UV Luminosity Functions at the Infall Region of the Coma Cluster

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    We have used deep GALEX observations at the infall region of the Coma cluster to measure the faintest UV luminosity functions (LFs) presented for a rich galaxy cluster thus far. The Coma UV LFs are measured to M_UV = -10.5 in the GALEX FUV and NUV bands, or 3.5 mag fainter than previous studies, and reach the dwarf early-type galaxy population in Coma for the first time. The Schechter faint-end slopes (alpha = -1.39 in both GALEX bands) are shallower than reported in previous Coma UV LF studies owing to a flatter LF at faint magnitudes. A Gaussian-plus-Schechter model provides a slightly better parametrization of the UV LFs resulting in a faint-end slope of ~ -1.15 in both GALEX bands. The two-component model gives faint-end slopes shallower than -1 (a turnover) for the LFs constructed separately for passive and star forming galaxies. The UV LFs for star forming galaxies show a turnover at M_UV ~ -14 owing to a deficit of dwarf star forming galaxies in Coma with stellar masses below M*=10^8 Msun. A similar turnover is identified in recent UV LFs measured for the Virgo cluster suggesting this may be a common feature of local galaxy clusters, whereas the field UV LFs continue to rise at faint magnitudes. We did not identify an excess of passive galaxies as would be expected if the missing dwarf star forming galaxies were quenched inside the cluster. In fact, the LFs for both dwarf passive and star forming galaxies show the same turnover at faint magnitudes. We discuss the possible origin of the missing dwarf star forming galaxies in Coma and their expected properties based on comparisons to local field galaxies.Comment: accepted for publication in Ap

    Ice Age Epochs and the Sun's Path Through the Galaxy

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    We present a calculation of the Sun's motion through the Milky Way Galaxy over the last 500 million years. The integration is based upon estimates of the Sun's current position and speed from measurements with Hipparcos and upon a realistic model for the Galactic gravitational potential. We estimate the times of the Sun's past spiral arm crossings for a range in assumed values of the spiral pattern angular speed. We find that for a difference between the mean solar and pattern speed of Omega_Sun - Omega_p = 11.9 +/- 0.7 km/s/kpc the Sun has traversed four spiral arms at times that appear to correspond well with long duration cold periods on Earth. This supports the idea that extended exposure to the higher cosmic ray flux associated with spiral arms can lead to increased cloud cover and long ice age epochs on Earth.Comment: 14 pages, 3 figures, accepted for publication in Ap

    Stories as personal coaching philosophy

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    The importance of coaches developing and articulating a personal coaching philosophy which encapsulates their values and beliefs is widely recognised. Yet it is also acknowledged that many coaches resist what appears an abstract task or find it to be of limited use in their day-to-day practice. In this paper we explore the potential of an alternative approach to developing and articulating a personal coaching philosophy: storytelling. Following a discussion of the potential of stories, we present a story written by one coach which expresses her personal philosophy in a way that is firmly rooted in her coaching practice. Storytelling approaches, we suggest, can reveal the connections between abstract/general philosophy and the personal embodied experience of coaching. We reflect on the possibilities and problems of using stories as philosophy and offer some suggestions for how coaches may be supported in developing their coaching philosophy through storytelling

    Sand as Maxwell's demon

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    We consider a dilute gas of granular material inside a box, kept in a stationary state by shaking. A wall separates the box into two identical compartments, save for a small hole at some finite height hh. As the gas is cooled, a second order phase transition occurs, in which the particles preferentially occupy one side of the box. We develop a quantitative theory of this clustering phenomenon and find good agreement with numerical simulations

    The Decay D0→Kˉ∗0π−e+ÎœeD^0\to \bar K^{*0} \pi^- e^+ \nu_e in the Context of Chiral Perturbation Theory

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    We study the decay D0→Kˉ∗0π−e+ÎœeD^0\rightarrow \bar K^{*0} \pi^- e^+ \nu_e, using SU(2)L⊗SU(2)RSU(2)_L \otimes SU(2)_R chiral perturbation theory for heavy charmed mesons and vector mesons, in the kinematic regime where pM⋅pπ/mMp_M \cdot p_\pi/m_M (here M=D0M = D^0 or Kˉ∗0\bar K^{*0}) is much smaller than the chiral symmetry breaking scale, ΛχSB\Lambda_{\chi SB} ( ΛχSB∌\Lambda_{\chi SB} \sim 1 GeV). We present the leading diagrams and amplitude, and calculate the rate, in the region where, to leading order in our calculations, the Kˉ∗0\bar K^{*0} is at zero recoil in the D0D^0 rest frame. The rate thus calculated is given in terms of a known form factor and depends on the DD∗πDD^* \pi coupling constant gDg_D of the heavy (charmed) meson chiral perturbation theory Lagrangian. A measurement of the above decay, in the aforementioned kinematic regime, can result in the extraction of an experimental value for gDg_D, accurate at the level of our approximations, and give us a measure of the validity of approaches based on chiral perturbation theory in studying similar processes.Comment: 17 pages, Latex, 2 embedded postscript figure
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