2,147 research outputs found
Count three for wear able computers
This paper is a postprint of a paper submitted to and accepted for publication in the Proceedings of the IEE Eurowearable 2003 Conference, and is subject to Institution of Engineering and Technology Copyright. The copy of record is available at the IET Digital Library.
A revised version of this paper was also published in Electronics Systems and Software, also subject to Institution of Engineering and Technology Copyright. The copy of record is also available at the IET Digital Library.A description of 'ubiquitous computer' is presented. Ubiquitous computers imply portable computers embedded into everyday objects, which would replace personal computers. Ubiquitous computers can be mapped into a three-tier scheme, differentiated by processor performance and flexibility of function. The power consumption of mobile devices is one of the most important design considerations. The size of a wearable system is often a design limitation
Variation of turbulent burning rate of methane, methanol, and iso-octane air mixtures with equivalence ratio at elevated pressure
Turbulent burning velocities for premixed methane, methanol, and iso-octane/air mixtures have been experimentally determined for an rms turbulent velocity of 2 m/s and pressure of 0.5 MPa for a wide range of equivalence ratios. Turbulent burning velocity data were derived using high-speed schlieren photography and transient pressure recording; measurements were processed to yield a turbulent mass rate burning velocity, utr. The consistency between the values derived using the two techniques, for all fuels for both fuel-lean and fuel-rich mixtures, was good. Laminar burning measurements were made at the same pressure, temperature, and equivalence ratios as the turbulent cases and laminar burning velocities and Markstein numbers were determined. The equivalence ratio (φ) for peak turbulent burning velocity proved not always coincident with that for laminar burning velocity for the same fuel; for isooctane, the turbulent burning velocity unexpectedly remained high over the range φ= 1 to 2. The ratio of turbulent to laminar burning velocity proved remarkably high for very rich iso-octane/air and lean methane/air mixtures
Quantum interface between an electrical circuit and a single atom
We show how to bridge the divide between atomic systems and electronic
devices by engineering a coupling between the motion of a single ion and the
quantized electric field of a resonant circuit. Our method can be used to
couple the internal state of an ion to the quantized circuit with the same
speed as the internal-state coupling between two ions. All the well-known
quantum information protocols linking ion internal and motional states can be
converted to protocols between circuit photons and ion internal states. Our
results enable quantum interfaces between solid state qubits, atomic qubits,
and light, and lay the groundwork for a direct quantum connection between
electrical and atomic metrology standards.Comment: Supplemental material available on reques
Rotational Effects of Twisted Light on Atoms Beyond the Paraxial Approximation
The transition probability for the emission of a Bessel photon by an atomic
system is calculated within first order perturbation theory. We derive a closed
expression for the electromagnetic potentials beyond the paraxial approximation
that permits a systematic multipole approximation . The matrix elements between
center of mass and internal states are evaluated for some specially relevant
cases. This permits to clarify the feasibility of observing the rotational
effects of twisted light on atoms predicted by the calculations. It is shown
that the probability that the internal state of an atom acquires orbital
angular momentum from light is, in general, maximum for an atom located at the
axis of a Bessel mode. For a Gaussian packet, the relevant parameter is the
ratio of the spread of the atomic center of mass wave packet to the transversal
wavelength of the photon.Comment: 10 pages, no figure
Real-time digital-computer-hardware simulation of a spacecraft with control-moment-gyroscope stabilization
Computer simulation of Apollo Telescope Mount to evaluate performance of control moment gyroscope system used for stabilizatio
On the Quantum Theory of Molecules
Transition state theory was introduced in the 1930s to account for chemical
reactions. Central to this theory is the idea of a potential energy surface
(PES). It was assumed that such a surface could be constructed using
eigensolutions of the Schr\"{o}dinger equation for the molecular (Coulomb)
Hamiltonian but at that time such calculations were not possible. Nowadays
quantum mechanical ab-initio electronic structure calculations are routine and
from their results PESs can be constructed which are believed to approximate
those assumed derivable from the eigensolutions. It is argued here that this
belief is unfounded. It is suggested that the potential energy surface
construction is more appropriately regarded as a legitimate and effective
modification of quantum mechanics for chemical purpose
A near-infrared spectroscopic screening of the red giant populations in omega Centauri
Near-infrared spectra of 21 giants in omega Centauri, spanning the whole
range of metallicities observed in this cluster, are presented. This work is
part of a coordinated photometric and spectroscopic campaign in the optical and
in the infrared, aimed at studying the complex stellar population of omega
Centauri and understanding its formation and chemical evolution. By analyzing
the several CO and OH molecular bands and atomic lines in the spectra of the
selected giants, metal abundances and abundance ratios have been obtained. The
existence of three major metallicity regimes at [Fe/H]=-1.6, -1.2 and
[Fe/H]<-0.5 has been confirmed. The most metal-rich stars in our sample show a
lower (if any) alpha-enhancement when compared to the more metal-poor
components, suggesting that they should have formed in a medium significantly
polluted by type Ia supernova ejecta. Isotopic carbon abundances have been also
inferred, providing an average 13C/12C=4, which clearly indicates that
extra-mixing processes occurred in the stellar interiors during the ascent on
the Red Giant Branch.Comment: 22 pages, 7 .ps figures. aastex. Accepted for pubilcation in the
Astrophysical Journa
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