This writeup is a compilation of the predictions for the forthcoming Heavy Ion Program at the Large Hadron Collider, as presented at the CERN Theory Institute ‘Heavy Ion Collisions at the LHC—Last Call for Predictions’, held from 14th May to 10th June 2007.

Solid Freeform Fabrication SFF processes have demonstrated the ability to produce parts with locally controlled composition. In the limit, processes such as 3D Printing can create parts with composition control on a length scale of 100 m. To exploit this potential, new methods to model, exchange, and process parts with local composition control need to be developed. An approach to modeling a part's geometry, topology, and composition is presented. This approach is based on subdividing the solid model into sub-regions and associating analytic composition blending functions with each region. These blending functions de ne the composition throughout the model as mixtures of the primary materials available to the SFF machine. Design tools based u p on distance functions are also introduced, such as the speci cation of composition as a function of the distance from the surface of a part. Finally, the role of design rules restricting maximum and minimum concentrations is discussed.

A set of condensation experiments in the presence of noncondensables (e.g. air, helium) were conducted to evaluate the heat removal capacity of a passive cooling unit in a postaccident containment.Condensation heat transfer coefficients on a vertically mounted smooth tube have been obtained for total pressure ranging from 36 psia to 66 psia, and air mass fraction ranging from 0.30 to 0.65. An empirical correlation has been developed in term of a parameter group made up of steam mole fraction(Xs), total pressure(P), temperature difference between bulk gas and wall surface (dT). This correlation covers all data points within 20%. All data points are also in good agreement with the prediction of the Diffusion Layer Model (DLM) with suction. The effect of helium (simulating hydrogen) on heat transfer coefficient was investigated for helium mole fraction in noncondensable gases Xhe/Xnc at 15%, 30% and 60%. It was found that the condensation heat transfer coefficients are generally lower when introducing helium into noncondensable gas. The difference is within 20% of air-only cases when Xhe/Xnc is less than 30% and total pressure is less than 66 psia. A gas stratification phenomenon was clearly observed for helium mole fraction in excess of 60%. The limiting case of the shadowing effect in a tube bundle has been investigated by adding a shroud around the smooth tube. It was found that the average heat removal capability is reduced by a factor of 0.6.

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