Methods and systems for electronics assembly system consultation and sales build upon an approach to modeling and simulation of such systems in which the system is modeled at a preselected level of abstraction, which in the preferred embodiment of the invention is the material flow level of abstraction. The apparatus or system may comprise a moving-bed or a simulated moving-bed adsorption means. When diafiltration is performed, an additional removal of substances occurs by convection as a larger portion of plasma water from a blood compartment can be filtered across a semi-permeable membrane at the same transmembrane pressure due to the reduced viscosity of the heated blood and plasma water. A method of using a disposable undergarment includes stretching at least one of the back sheet and the top sheet. In one embodiment, the number of secondary bonus awards is determined based on the number of active gaming machines.