Methods for the production of carbon foam from swelling coals that do not require the use of high process pressures, oxidized coal, devolatized coal, or high-strength, foam expansion confining molds are described. A Christmas tree stand comprises a supporting base and non-penetrative one-way-pushable screws. The portion of the stent having helical elements provides a high percentage of covered area for example, in an aneurysm area. Other devices such as fans, cooling fins, coolant circulation systems and the like can be employed by the apparatus to further facilitate dissipation of the heat energy from the cooling surface. In this manner, model changes are considered on a case-by-case basis to determine an extent, if any, to which subsets should be re-computed. The scheduling methodology is implemented at the Master and therefore has access to information about the Master queues.