53,299 research outputs found
On the predominant mechanisms active during the high power diode laser modification of the wettability characteristics of an SiO2/Al2O3-based ceramic material
The mechanisms responsible for modifications to the wettability characteristics of a SiO2/Al2O3-based ceramic material in terms of a test liquid set comprising of human blood, human blood plasma, glycerol and 4-octonol after high power diode laser (HPDL) treatment have been elucidated. Changes in the contact angle, , and hence the wettability characteristics of the SiO2/Al2O3-based ceramic were attributed primarily to: modifications to the surface roughness of the ceramic resulting from HPDL interaction which accordingly effected reductions in ; the increase in the surface O2 content of the ceramic after HPDL treatment; since an increase in surface O2 content intrinsically brings about a decrease in , and vice versa and the increase in the polar component of the surface energy, due to the HPDL induced surface melting and resolidification which consequently created a partially vitrified microstructure that was seen to augment the wetting action. However, the degree of influence exerted by each mechanism was found to differ markedly. Isolation of each of these mechanisms permitted the magnitude of their influence to be qualitatively determined. Surface energy, by way of microstructural changes, was found to be by far the most predominant element governing the wetting characteristics of the SiO2/Al2O3-based ceramic. To a much lesser extent, surface O2 content, by way of process gas, was also seen to influence to a changes in the wettability characteristics of the SiO2/Al2O3-based ceramic, whilst surface roughness was found to play a minor role in inducing changes in the wettability characteristics
VISHNU hybrid model for viscous QCD matter at RHIC and LHC energies
In this proceeding, we briefly describe the viscous hydrodynamics + hadron
cascade hybrid model VISHNU for relativistic heavy ion collisions and report
the current status on extracting the QGP viscosity from elliptic flow data.Comment: 4 pages, 1 figure, the proceedings of 7th International Workshop on
Critical Point and Onset of Deconfinement, Wuhan, China, Nov. 7-11, 201
Warm dust in the terrestrial planet zone of a sun-like Pleiad: collisions between planetary embryos?
Only a few solar-type main sequence stars are known to be orbited by warm
dust particles; the most extreme is the G0 field star BD+20 307 that emits ~4%
of its energy at mid-infrared wavelengths. We report the identification of a
similarly dusty star HD 23514, an F6-type member of the Pleiades cluster. A
strong mid-IR silicate emission feature indicates the presence of small warm
dust particles, but with the primary flux density peak at the non-standard
wavelength of ~9 micron. The existence of so much dust within an AU or so of
these stars is not easily accounted for given the very brief lifetime in orbit
of small particles. The apparent absence of very hot (>~1000 K) dust at both
stars suggests the possible presence of a planet closer to the stars than the
dust. The observed frequency of the BD+20 307/HD 23514 phenomenon indicates
that the mass equivalent of Earth's Moon must be converted, via collisions of
massive bodies, to tiny dust particles that find their way to the terrestrial
planet zone during the first few hundred million years of the life of many
(most?) sun-like stars. Identification of these two dusty systems among
youthful nearby solar-type stars suggests that terrestrial planet formation is
common.Comment: ApJ in press, 19 pages including 3 figures and 2 tables, minor
changes to the tables and figure
Generalization of the Darboux transformation and generalized harmonic oscillators
The Darbroux transformation is generalized for time-dependent Hamiltonian
systems which include a term linear in momentum and a time-dependent mass. The
formalism for the -fold application of the transformation is also
established, and these formalisms are applied for a general quadratic system (a
generalized harmonic oscillator) and a quadratic system with an inverse-square
interaction up to N=2. Among the new features found, it is shown, for the
general quadratic system, that the shape of potential difference between the
original system and the transformed system could oscillate according to a
classical solution, which is related to the existence of coherent states in the
system
Off-shell effects in dilepton production from hot interacting mesons
The production of dielectrons in reactions involving a_1 mesons and pions is
studied. We compare results obtained with different phenomenological
Lagrangians that have been used in connection with hadronic matter and finite
nuclei. We insist on the necessity for those interactions to satisfy known
empirical properties of the strong interaction. Large off-shell effects in
dielectron production are found and some consequences for the interpretation of
heavy ion data are outlined. We also compare with results obtained using
experimentally-extracted spectral functions.Comment: 14 pages, LaTeX2e, 2 figure
q-Deformation of W(2,2) Lie algebra associated with quantum groups
An explicit realization of the W(2,2) Lie algebra is presented using the
famous bosonic and fermionic oscillators in physics, which is then used to
construct the q-deformation of this Lie algebra. Furthermore, the quantum group
structures on the q-deformation of this Lie algebra are completely determined.Comment: 12 page
Seamless handover in software-defined satellite networking
Satellites have largely been designed as application specific and isolated for the past decades. Though with certain benefits, it might lead to resource under utilization and limited satellite applications. As an emerging networking technology, software-defined networking (SDN) has recently been introduced into satellite networks. In this letter, we propose a software defined satellite networking (SDSN) architecture, which simplifies networking among versatile satellites and enables new protocols to be easily tested and deployed. Particularly, we propose a seamless handover mechanism based on SDSN, and conduct physical layer simulation, which shows significant improvement over the existing hard handover and hybrid handover mechanisms in terms of handover latency, throughput and quality of experience
of users
Tourism demand modelling and forecasting : how should demand be measured?
2009-2010 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe
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