Nucleation of Quark--Gluon Plasma from Hadronic Matter

The energy densities achieved during central collisions of large nuclei at Brookhaven's AGS may be high enough to allow the formation of quark--gluon plasma. Calculations based on relativistic nucleation theory suggest that rare events, perhaps one in every 10$^2$ or 10$^3$, undergo the phase transition. Experimental ramifications may include an enhancement in the ratio of pions to baryons, a reduction in the ratio of deuterons to protons, and a larger source size as seen by hadron interferometry.Comment: 22 pages, 7 figures available upon request, NUC--MINN--94/5--

Scattering in the Presence of Electroweak Phase Transition Bubble Walls

We investigate the motion of fermions in the presence of an electro\-weak phase transition bubble wall. We derive and solve the Dirac equation for such fer\-mions, and compute the transmission and reflection coefficients for fermions traveling from the symmetric to the asymmetric phases separated by the domain wall.Comment: TPI--MINN--54, NUC--MINN--93/30--T, UMN--TH--1226/93, LaTex, 29 page

Louis I. Kahn and Richard Kelly: collaborative design in creation of the luminous environment

As one of the most prominent architects of the twentieth century, Louis I. Kahn aspired to use natural light to shape his architecture. The lighting designer Richard Kelly, one of his close collaborators, had significant influence on modern architectural lighting design in the twentieth century. Kahn and Kelly designed the luminous environments in three art-gallery and museum buildings, The Yale University Art Gallery, the Kimbell Art Museum and the Yale Center for British Art. Collaboration between the architect and the lighting designer resulted in well-resolved lighting solutions. This research investigated the collaboration between Louis I. Kahn and Richard Kelly from both theoretical and pragmatic perspectives. In terms of the theoretical perspective, a detailed overview of their collaborative work is provided through literature review. In terms of the pragmatic perspective, the background of their cooperation and the technical details are presented. In addition, daylighting performance analysis of these three buildings through digital modelling was undertaken. This study found that the lighting design solutions produced together by Louis I. Kahn and Richard Kelly, especially the way of using daylight, have had significant impact on architectural space and the luminous environment. More importantly, this kind of collaborative working method could provide a useful reference and guidance for contemporary architecture and lighting design