59,368 research outputs found
Simple, reproducible methods for thermal shock testing of brittle materials
Technique requires radio frequency induction power source, induction furnace and good vacuum system to induce brittle material thermal shock testing
Further developments in generating type-safe messaging
At ICALEPCS '09, we introduced a source code generator that allows processes
to communicate safely using data types native to each host language. In this
paper, we discuss further development that has occurred since the conference in
Kobe, Japan, including the addition of three more client languages, an
optimization in network packet size and the addition of a new protocol data
type.Comment: 4 pp. 13th International Conference on Accelerator and Large
Experimental Physics Control Systems (ICALEPCS 2011). 10-14 Oct 2011.
Grenoble, Franc
The standstill luminosity in Z Cam systems
We consider accretion discs in close binary systems. We show that heating of
a disc at the impact point of the accretion stream contributes significantly to
the local energy budget at its outer edge. As a result the thermal balance
relation between local accretion rate and surface density (the `S-curve')
changes; the critical mass transfer rate above which no dwarf nova outbursts
occur can be up to 40% smaller than without impact heating. Standstills in ZCam
systems thus occur at smaller mass transfer rates than otherwise expected, and
are rather fainter than the peak luminosity during the dwarf nova phase as a
result.Comment: 3 pages, 3 figures. Accepted for publication in MNRA
High-Resolution Spectroscopy of Ursa Major Moving Group Stars
We use new and extant literature spectroscopy to address abundances and
membership for UMa moving group stars. We first compare the UMa, Coma, and
Hyades H-R diagrams via a homogeneous set of isochrones, and find that these
three aggregates are essentially coeval. Our spectroscopy of cool UMa dwarfs
reveals striking abundance anomalies--trends with Teff, ionization state, and
excitation potential--like those recently seen in young cool M34, Pleaides, and
Hyades dwarfs. In particular, the trend of rising 7774 Ang-based OI abundance
with declining Teff is markedly subdued in UMa compared to the Pleiades,
suggesting a dependence on age or metallicity. Despite disparate sources of Li
data,our homogeneous analysis indicates that UMa members evince remarkably
small scatter in the Li-Teff plane for Teff>5200 K. Significant star-to-star
scatter suggested by previous studies is seen for cooler stars. Comparison with
the consistently determined Hyades Li-Teff trend reveals differences
qualitatively consistent with this cluster's larger [Fe/H] (and perhaps
slightly larger age). However, quantitative comparison with standard stellar
models indicates the differences are smaller than expected, suggesting the
action of a fourth parameter beyond age, mass, and [Fe/H] controlling Li
depletion.Comment: To appear in Publ. Astron. Soc. Pacif. (September 2005
Master/slave manipulator system
System capabilities are equivalent to mobility, dexterity, and strength of human arm. Arrangement of torque motor, harmonic drive, and potentiometer combination allows all power and control leads to pass through center of slave with position-transducer arrangement of master, and "stovepipe joint" is incorporated for manipulator applications
Anthropomorphic master/slave manipulator system
An anthropomorphic master/slave manipulator system including master arm apparatus with a plurality of master tubular articulated portions is outlined. Objectives of this investion were to provide a system that accurately and smoothly simulates human limb movement at a remote location. The system has a high frequency response, a high structural stiffness and a design that protects the components of the slave mechanism. Simulation of human movements is possible in outer space, underwater, and in a hazardous environment such as in a high radiation area. The equivalent ability, dexterity, and strength of a human arm are simulated
Hopf algebras and characters of classical groups
Schur functions provide an integral basis of the ring of symmetric functions.
It is shown that this ring has a natural Hopf algebra structure by identifying
the appropriate product, coproduct, unit, counit and antipode, and their
properties. Characters of covariant tensor irreducible representations of the
classical groups GL(n), O(n) and Sp(n) are then expressed in terms of Schur
functions, and the Hopf algebra is exploited in the determination of
group-subgroup branching rules and the decomposition of tensor products. The
analysis is carried out in terms of n-independent universal characters. The
corresponding rings, CharGL, CharO and CharSp, of universal characters each
have their own natural Hopf algebra structure. The appropriate product,
coproduct, unit, counit and antipode are identified in each case.Comment: 9 pages. Uses jpconf.cls and jpconf11.clo. Presented by RCK at
SSPCM'07, Myczkowce, Poland, Sept 200
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