Collective flow and two-pion correlations from a relativistic hydrodynamic model with early chemical freeze out

We investigate the effect of early chemical freeze-out on radial flow, elliptic flow and HBT radii by using a fully three dimensional hydrodynamic model. When we take account of the early chemical freeze-out, the space-time evolution of temperature in the hadron phase is considerably different from the conventional model in which chemical equilibrium is always assumed. As a result, we find that radial and elliptic flows are suppressed and that the lifetime and the spatial size of the fluid are reduced. We analyze the p_t spectrum, the differential elliptic flow, and the HBT radii at the RHIC energy by using hydrodynamics with chemically non-equilibrium equation of state.Comment: One subsection and two figures adde

MoEDAL search in the CMS beam pipe for magnetic monopoles produced via the Schwinger effect

We report on a search for magnetic monopoles (MMs) produced in ultraperipheral Pb-Pb collisions during Run 1 of the LHC. The beam pipe surrounding the interaction region of the CMS experiment was exposed to 184.07  μ⁢b−1 of Pb-Pb collisions at 2.76 TeV center-of-mass energy per collision in December 2011, before being removed in 2013. It was scanned by the MoEDAL experiment using a SQUID magnetometer to search for trapped MMs. No MM signal was observed. The two distinctive features of this search are the use of a trapping volume very close to the collision point and ultrahigh magnetic fields generated during the heavy-ion run that could produce MMs via the Schwinger effect. These two advantages allowed setting the first reliable, world-leading mass limits on MMs with high magnetic charge. In particular, the established limits are the strongest available in the range between 2 and 45 Dirac units, excluding MMs with masses of up to 80 GeV at a 95% confidence level

Heat Transfer Research; Findings in Heat Transfer Research Reported from Multimedia University

According to the news reporters, the research concluded: "The results indicate that both heat transfer coefficient and heat flux are of considerably high values, confirming that the heat transport capability of a micro heat pipe is dominated by the phase-change heat transfer at the liquid-vapor interface

Heat Transfer Research; Data on Heat Transfer Research Described by Researchers at Multimedia University

According to the news editors, the research concluded: "The effects of gravity, through the angle of inclination, on the heat transport capacity, the optimal charge level of the working fluid, the liquid volume fraction distribution, the circulation strength of working fluid and the solid wall temperature distribution are analysed, to provide a better insight for the design of inclined micro heat pipes.

MOMENTUM INTEGRAL METHOD FOR FORCED CONVECTION IN THERMAL NONEQUILIBRIUM POWER-LAW FLUID-SATURATED POROUS MEDIA

Forced convection heat transfer for power-law fluid flow in porous media was studied analytically. The analytical solutions were obtained based on the Brinkman-extended Darcy model for fluid flow and the two-equation model for forced convection heat transfer. As a closed-form exact velocity profile is unobtainable for the general power-law index, an approximate velocity profile based on the parabolic model is proposed by subscribing to the momentum boundary layer integral method. Heat transfer analysis is based on the two-equation model by considering local thermal nonequilibrium between fluid and solid phases and constant heat flux boundary conditions. The velocity and temperature distributions obtained based on the parabolic model were verified to be reasonably accurate and improvement is justified compared to the linear model. The expression for the overall Nusselt number was derived based on the proposed parabolic model. The effects of the governing parameters of engineering importance such as Darcy number, power-law index, nondimensional interfacial heat transfer coefficient, and effective thermal conductivity ratio on the convective heat transfer characteristics of non-Newtonian fluids in porous media are analyzed and discussed

Electromigration of Sn-9wt.%Zn solder

The morphological evolution of Sn-9wt.%Zn solder under electromigration at a current density of about 10(5) A/cm(2) was examined. Sn extrusion was observed, suggesting that Sn is the dominant moving species under electromigration. In contrast, Zn appeared to be immobile. It was also found that the microstructure of the solder had a significant effect on the electromigration behavior. For the solder with f ine Zn precipitates, the surface morphology of the solder was almost unchanged except for the formation of Sn extrusion sites at the anode side after electromigration. However, for the solder with coarse Zn precipitates, more Sn extrusion sites were observed, and they were located not only at the anode side but also within the solder. Coarse Zn precipitates appeared to block Sn migration, thus Sn migration was intercepted in front of the Zn precipitates. The Sn atoms accumulated there, which led to its extrusion. The blocking effect was found to depend strongly on the size and orientation of the Zn precipitates

Electromigration of Sn-8 wt.% Zn-3 wt.% Bi and Sn-9 wt.% Zn-1 wt.% Cu solders

Stripe-type Cu/solder/Cu reaction couples were utilized to investigate electromigration behaviors of Sn-8Zn-3Bi and Sn-9Zn-1Cu (in wt.%) solders under current stressing with a density of 10(5) A/cm(2) at 80-125 degrees C. Two cooling conditions, fan and furnace cooling, were performed after the solders was reflowed on the Cu stripe. No noticeable microstructural change was found in the fan-cooled Sn-8Zn-3Bi solder at 80 degrees C except that Bi migrated along with the electron flow toward the anode. While significant microstructural change was found at 125 degrees C, indicating that electromigration effect is enhanced at higher temperatures. Sn was extruded in front of the Cu electrode at the anode side and voids were formed in the solder near the cathode side. For the furnace-cooled solder, microstructural change was found even at 80 degrees C. For the Sn-9Zn-1Cu solder, regardless of fan or furnace cooling, Sn extrusion and voids were formed at the anode and cathode sides, respectively, after current stressing at 80 degrees C. Voids were formed in the solder and mainly surrounded the Cu-Zn compounds. (c) 2008 Elsevier B.V. All rights reserved