43,815 research outputs found
Operation of a forced circulation, haynes alloy no. 25, mercury loop to study corrosion product separation techniques
Forced circulation, Haynes alloy 25, mercury loop to study corrosion product separatio
Operation of a haynes alloy no. 25 forced circulation loop to study the effects of hydrogen in a simulated sunflower system
Haynes alloy forced circulation mercury loop for studying hydrogen effects in working fluid of Rankine cycle Sunflower solar power syste
Operation of a forced circulation, croloy 9 m, mercury loop to study corrosion product separation techniques
Forced circulation, Croloy 9M mercury loop designed to investigate corrosion product separation technique
On the origin and application of the Bruggeman correlation for analysing transport phenomena in electrochemical systems
The widely used Bruggeman equations correlate tortuosity factors of porous media with their porosity. Finding diverse application from optics to bubble formation, it received considerable attention in fuel cell and battery research, recently. The ability to estimate tortuous mass transport resistance based on porosity alone is attractive, because direct access to the tortuosity factors is notoriously difficult. The correlation, however, has limitations, which are not widely appreciated owing to the limited accessibility of the original manuscript. We retrace Bruggeman's derivation, together with its initial assumptions, and comment on validity and limitations apparent from the original work to offer some guidance on its use
Non-equilibrium dynamics in quantum field theory at high density: the tsunami
The dynamics of a dense relativistic quantum fluid out of thermodynamic
equilibrium is studied in the framework of the Phi^4 scalar field theory in the
large N limit. The time evolution of a particle distribution in momentum space
(the tsunami) is computed. The effective mass felt by the particles in such a
high density medium equals the tree level mass plus the expectation value of
the squared field. The case of negative tree level squared mass is particularly
interesting. In such case dynamical symmetry restoration as well as dynamical
symmetry breaking can happen. Furthermore, the symmetry may stay broken with
vanishing asymptotic squared mass showing the presence of out of equilibrium
Goldstone bosons. We study these phenomena and identify the set of initial
conditions that lead to each case. We compute the equation of state which turns
to depend on the initial state. Although the system does not thermalize, the
equation of state for asymptotically broken symmetry is of radiation type. We
compute the correlation functions at equal times. The two point correlator for
late times is the sum of different terms. One stems from the initial particle
distribution. Another term accounts for the out of equilibrium Goldstone bosons
created by spinodal unstabilities when the symmetry is asymptotically
broken.Both terms are of the order of the inverse of the coupling for distances
where causal signals can connect the two points. The contribution of the out of
equilibrium Goldstones exhibits scaling behaviour in a generalized sense.Comment: LaTex, 49 pages, 15 .ps figure
Super high compression of line drawing data
Models which can be used to accurately represent the type of line drawings which occur in teleconferencing and transmission for remote classrooms and which permit considerable data compression were described. The objective was to encode these pictures in binary sequences of shortest length but such that the pictures can be reconstructed without loss of important structure. It was shown that exploitation of reasonably simple structure permits compressions in the range of 30-100 to 1. When dealing with highly stylized material such as electronic or logic circuit schematics, it is unnecessary to reproduce configurations exactly. Rather, the symbols and configurations must be understood and be reproduced, but one can use fixed font symbols for resistors, diodes, capacitors, etc. Compression of pictures of natural phenomena such as can be realized by taking a similar approach, or essentially zero error reproducibility can be achieved but at a lower level of compression
Gauge Fields Out-Of-Equilibrium: A Gauge Invariant Formulation and the Coulomb Gauge
We study the abelian Higgs model out-of-equilibrium in two different
approaches, a gauge invariant formulation, proposed by Boyanovsky et al.
\cite{Boyanovsky:1996dc} and in the Coulomb gauge. We show that both approaches
become equivalent in a consistent one loop approximation. Furthermore, we carry
out a proper renormalization for the model in order to prepare the equations
for a numerical implementation. The additional degrees of freedom, which arise
in gauge theories, influence the behavior of the system dramatically. A
comparison with results in the 't Hooft-Feynman background gauge found by us
recently, shows very good agreement.Comment: 32 pages, 8 figure
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