Preparation, characterization, physical testing and performance of fluorocarbon membranes and separators

The direct fluorination method of converting carefully selected hydrocarbon substrates to fluorinated membranes was successfully applied to produce promising, novel membranes for electrochemical devices. A family of polymer blends was identified which permits wide latitude in the concentration of both crosslinks and carboxyl groups in hydrocarbon membranes. These membranes were successfully fluorinated and are potentially competitive with commercial membranes in performance, and potentially much cheaper in price

Preparation, characterization, physical testing and performance of flurocarbon membranes and separators

The direct fluorination method of converting carefully selected hydrocarbon substrates to fluorinated membranes was successfully applied to produce promising, novel membranes for electrochemical devices. A family of polymer blends was identified which permits wide latitude in the concentration of both crosslinks and carboxyl groups in hydrocarbon membranes. The membranes of paragraph two were successfully fluorinated

Two-point functions for SU(3) Polyakov Loops near T_c

We discuss the behavior of two point functions for Polyakov loops in a SU(3) gauge theory about the critical temperature, T_c. From a Z(3) model, in mean field theory we obtain a prediction for the ratio of masses at T_c, extracted from correlation functions for the imaginary and real parts of the Polyakov loop. This ratio is m_i/m_r = 3 if the potential only includes terms up to quartic order in the Polyakov loop; its value changes as pentic and hexatic interactions become important. The Polyakov Loop Model then predicts how m_i/m_r changes above T_c.Comment: 5 pages, no figures; reference adde

Hadronic freeze-out following a first order hadronization phase transition in ultrarelativistic heavy-ion collisions

We analyze the hadronic freeze-out in ultra-relativistic heavy ion collisions at RHIC in a transport approach which combines hydrodynamics for the early, dense, deconfined stage of the reaction with a microscopic non-equilibrium model for the later hadronic stage at which the hydrodynamic equilibrium assumptions are not valid. With this ansatz we are able to self-consistently calculate the freeze-out of the system and determine space-time hypersurfaces for individual hadron species. The space-time domains of the freeze-out for several hadron species are found to be actually four-dimensional, and di er drastically for the individual hadrons species. Freeze-out radii distributions are similar in width for most hadron species, even though the is found to be emitted rather close to the phase boundary and shows the smallest freeze- out radii and times among all baryon species. The total lifetime of the system does not change by more than 10% when going from SPS to RHIC energies

On possible implications of gluon number fluctuations in DIS data

We study the effect of gluon number fluctuations (Pomeron loops) on deep inelastic scattering (DIS) in the fixed coupling case. We find that the description of the DIS data is improved once gluon number fluctuations are included. Also the values of the parameters, like the saturation exponent and the diffussion coefficient, turn out reasonable and agree with values obtained from numerical simulations of toy models which take into account fluctuations. This outcome seems to indicate the evidence of geometric scaling violations, and a possible implication of gluon number fluctuations, in the DIS data. However, we cannot exclude the possibility that the scaling violations may also come from the diffusion part of the solution to the BK-equation, instead of gluon number fluctuations.Comment: 9 pages, 2 figures; references added, minor changes, matches published versio

Dimension 2 condensates and Polyakov Chiral Quark Models

We address a possible relation between the expectation value of the Polyakov loop in pure gluodynamics and full QCD based on Polyakov Chiral Quark Models where constituent quarks and the Polyakov loop are coupled in a minimal way. To this end we use a center symmetry breaking Gaussian model for the Polyakov loop distribution which accurately reproduces gluodynamics data above the phase transition in terms of dimension 2 gluon condensate. The role played by the quantum and local nature of the Polyakov loop is emphasized.Comment: 3 pages, 1 figure. Talk given at the IVth International Conference on Quarks an Nuclear Physics, Madrid, June 5th-10th 200

Hydrodynamic Models for Heavy-Ion Collisions, and beyond

A generic property of a first-order phase transition in equilibrium, and in the limit of large entropy per unit of conserved charge, is the smallness of the isentropic speed of sound in the ``mixed phase''. A specific prediction is that this should lead to a non-isotropic momentum distribution of nucleons in the reaction plane (for energies around 40 AGeV in our model calculation). On the other hand, we show that from present effective theories for low-energy QCD one does not expect the thermal transition rate between various states of the effective potential to be much larger than the expansion rate, questioning the applicability of the idealized Maxwell/Gibbs construction. Experimental data could soon provide essential information on the dynamics of the phase transition.Comment: 10 Pages, 4 Figures. Presented at 241st WE-Heraeus Seminar: Symposium on Fundamental Issues in Elementary Matter: In Honor and Memory of Michael Danos, Bad Honnef, Germany, 25-29 Sep 200