18,160 research outputs found
Indexed keyed connection Patent
Standard coupling design for mass productio
Satellite Power System. Concept development and evaluation program, volume 6: Construction and operations
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
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 magnetic moment is found to be in good agreement with
experiment: is predicted to be compared to the
experimental result of (2.02 0.05) .Comment: 19 pages, 2 figure
1/N_c Expansion of the Heavy Baryon Isgur-Wise Functions
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 PT
The paper deals with two issues. First, we explore the quantitiative
importance of higher multiplets for properties of the 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
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
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
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
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
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 . 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 in the Context of Chiral Perturbation Theory
We study the decay , using
chiral perturbation theory for heavy charmed mesons
and vector mesons, in the kinematic regime where (here or ) is much smaller than the chiral symmetry breaking
scale, ( 1 GeV). We present the
leading diagrams and amplitude, and calculate the rate, in the region where, to
leading order in our calculations, the is at zero recoil in the
rest frame. The rate thus calculated is given in terms of a known form
factor and depends on the coupling constant 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 , 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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