5,468 research outputs found
Ultraviolet instrumentation for orbital remote sensors
Ultraviolet instrumentation for orbital remote sensor
Energy Efficiency in Multi-hop CDMA Networks: A Game Theoretic Analysis
A game-theoretic analysis is used to study the effects of receiver choice on
the energy efficiency of multi-hop networks in which the nodes communicate
using Direct-Sequence Code Division Multiple Access (DS-CDMA). A Nash
equilibrium of the game in which the network nodes can choose their receivers
as well as their transmit powers to maximize the total number of bits they
transmit per unit of energy is derived. The energy efficiencies resulting from
the use of different linear multiuser receivers in this context are compared,
looking at both the non-cooperative game and the Pareto optimal solution. For
analytical ease, particular attention is paid to asymptotically large networks.
Significant gains in energy efficiency are observed when multiuser receivers,
particularly the linear minimum mean-square error (MMSE) receiver, are used
instead of conventional matched filter receivers.Comment: To appear in the Proceedings of the Workshop on Multi-Layer Modelling
and Design of Multi-Hop Wireless Networks (MLMD 06), Minneapolis, MN, July 12
- 15, 200
Advanced evaluation of vacuum UV detector- spectroscopy systems for capsule reentry measurements
Vacuum ultraviolet detector evaluation - spectroscopy systems for capsule reentry measurement
Electron capture to continuum in collisions of bare projectiles with Ne targets
Abstract. We have investigated the cusp resulting from electron capture to the continuum of 1.25-5 MeV m u- ' fully stripped hydrogen and oxygen as a function of the collision energy and the detector angular resolution B o. It is revealed that the characteristic cusp shape parameters depend strongly on the experimental resolution. Our experimental data are "pared with the second-order Born theory and the impulse approximation. Both theories mnhrm the 8, dependence of the shape parameters and gjve a reasonable descrip-lion of the cusp asymmetry. However, theory tends to overestimate the absolute cross sections, in particular in the case of oxygen. 1
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Conical Correlations, Bragg Peaks, and Transverse Flow Deflections in Jet Tomography
We use (3+1)-dimensional ideal hydrodynamics to describe a variety of
different jet energy loss scenarios for a jet propagating through an opaque
medium. The conical correlations obtained for fully stopped jets, revealing a
Bragg peak, are discussed as well as results from pQCD and AdS/CFT. Moreover,
we investigate transverse flow deflection. It is demonstrated that a
double-peaked away-side structure can be formed due to the different
contributions of several possible jet trajectories through an expanding medium.Comment: 4 pages, 3 figures - To appear in the conference proceedings for
Quark Matter 2009, March 30 - April 4, Knoxville, Tennessee, revised versio
From kinetic theory to dissipative fluid dynamics
We present the results of deriving the Israel-Stewart equations of
relativistic dissipative fluid dynamics from kinetic theory via Grad's
14-moment expansion. Working consistently to second order in the Knudsen
number, these equations contain several new terms which are absent in previous
treatments.Comment: 7 pages, proceedings of the Erice School on Nuclear Physics "Heavy
Ion collisions from the Coulomb Barrier up to the Quark Gluon Plasma", Erice,
Sicily, Sep. 16 - 24, 200
Jet Propagation and Mach Cones in (3+1)d Ideal Hydrodynamics
The observation of jet quenching and associated away--side Mach cone--like
correlations at RHIC provide powerful ``external'' probes of the sQGP produced
in A+A reactions, but it simultaneously raises the question where the jet
energy was deposited. The nearly perfect bulk fluidity observed via elliptic
flow suggests that Mach cone--like correlations may also be due to rapid local
equilibration in the wake of penetrating jets. Multi-particle correlations lend
further support to this possibility. However, a combined study of energy
deposition and fluid response is needed. We solve numerically 3--dimensional
ideal hydrodynamical equations to compute the flow correlation patterns
resulting from a variety of possible energy-momentum deposition models.
Mach--cone correlations are shown to depend critically on the energy and
momentum deposition mechanisms. They only survive for a special limited class
of energy--momentum loss models, which assume significantly less longitudinal
momentum loss than energy loss per unit length. We conclude that the correct
interpretation of away--side jet correlations will require improved
understanding and independent experimental constraints on the jet
energy--momentum loss to fluid couplings.Comment: 4 pages, 3 figures, To appear in the proceedings of Quark Matter 200
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