11,191 research outputs found
System size, energy and pseudorapidity dependence of directed and elliptic flow at RHIC
PHOBOS measurements of elliptic flow are presented as a function of
pseudorapidity, centrality, transverse momentum, energy and nuclear species.
The elliptic flow in Cu-Cu is surprisingly large, particularly for the most
central events. After scaling out the geometry through the use of an
alternative form of eccentricity, called the participant eccentricity, which
accounts for nucleon position fluctuations in the colliding nuclei, the
relative magnitude of the elliptic flow in the Cu-Cu system is qualitatively
similar to that measured in the Au-Au system.Comment: Presented at the 18th International Conference on Ultra-Relativistic
Nucleus-Nucleus Collisions in Budapest, Hungary, Aug. 4-9, 200
Energy and precious fuels requirements of fuel alcohol production. Volume 4: Appendices G and H, methanol from coal
Coal mine location, mining technology, energy consumption in mining, coal transport, and potential availability of coal are discussed. Methanol from coal is also discussed
Geoneutrinos in Borexino
This paper describes the Borexino detector and the high-radiopurity studies
and tests that are integral part of the Borexino technology and development.
The application of Borexino to the detection and studies of geoneutrinos is
discussed.Comment: Conference: Neutrino Geophysics Honolulu, Hawaii December 14-16, 200
Exploring the importance of reflection in the control room
While currently difficult to measure or explicitly design for, evidence suggests that providing people
with opportunities to reflect on experience must be recognized and valued during safety-critical
work. We provide an insight into reflection as a mechanism that can help to maintain both individual
and team goals. In the control room, reflection can be task-based, critical for the 'smooth' day-to-day
operational performance of a socio-technical system, or can foster learning and organisational change
by enabling new understandings gained from experience. In this position paper we argue that
technology should be designed to support the reflective capacity of people. There are many
interaction designs and artefacts that aim to support problem-solving, but very few that support
self-reflection and group reflection. Traditional paradigms for safety-critical systems have focussed
on ensuring the functional correctness of designs, minimising the time to complete tasks, etc. Work
in the area of user experience design may be of increasing relevance when generating artefacts that
aim to encourage reflection
3D Relativistic Hydrodynamic Computations Using Lattice-QCD-Inspired Equations of State
In this communication, we report results of three-dimensional hydrodynamic
computations, by using equations of state with a critical end point as
suggested by the lattice QCD. Some of the results are an increase of the
multiplicity in the mid-rapidity region and a larger elliptic-flow parameter
v2. We discuss also the effcts of the initial-condition fluctuations and the
continuous emission.Comment: 10 pages, 16 figures, prepared for Quark Matter 2005 Conferenc
Fundamental study of flow field generated by rotorcraft blades using wide-field shadowgraph
The vortex trajectory and vortex wake generated by helicopter rotors are visualized using a wide-field shadowgraph technique. Use of a retro-reflective Scotchlite screen makes it possible to investigate the flow field generated by full-scale rotors. Tip vortex trajectories are visible in shadowgraphs for a range of tip Mach number of 0.38 to 0.60. The effect of the angle of attack is substantial. At an angle of attack greater than 8 degrees, the visibility of the vortex core is significant even at relatively low tip Mach numbers. The theoretical analysis of the sensitivity is carried out for a rotating blade. This analysis demonstrates that the sensitivity decreases with increasing dimensionless core radius and increases with increasing tip Mach number. The threshold value of the sensitivity is found to be 0.0015, below which the vortex core is not visible and above which it is visible. The effect of the optical path length is also discussed. Based on this investigation, it is concluded that the application of this wide-field shadowgraph technique to a large wind tunnel test should be feasible. In addition, two simultaneous shadowgraph views would allow three-dimensional reconstruction of vortex trajectories
An Experimental Investigation of Fluid Flow and Heating in Various Resonance Tube Modes
Experiments have been performed to study resonance phenomena in tubes excited by underexpanded jet flows. This investigation comprised the following: Study of the various resonance tube modes under a wide range of nozzle pressure, spacing between nozzle and tube mouth, and different tube length; the effects of these modes on the endwall pressure and gas temperature; flow visualization of both jet and tube flows by spark shadowgraph technique; and measurement of wave speed inside the tube by the laser-schlieren techniques. An extensive study of the free-jet flow was undertaken to explain important aspects of various modes of operation of resonance tube flows
Elliptic Flow, Initial Eccentricity and Elliptic Flow fluctuations in Heavy Ion Collisions at RHIC
We present measurements of elliptic flow and event-by-event fluctuations
established by the PHOBOS experiment. Elliptic flow scaled by participant
eccentricity is found to be similar for both systems when collisions with the
same number of participants or the same particle area density are compared. The
agreement of elliptic flow between Au+Au and Cu+Cu collisions provides evidence
that the matter is created in the initial stage of relativistic heavy ion
collisions with transverse granularity similar to that of the participant
nucleons. The event-by-event fluctuation results reveal that the initial
collision geometry is translated into the final state azimuthal particle
distribution, leading to an event-by-event proportionality between the observed
elliptic flow and initial eccentricity.Comment: To appear in the proceedings of the Lake Louise Winter Institute
2007. The proceedings of the institute will be published by World Scientifi
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