A method and apparatus for supporting cache coherency in a multiprocessor computing environment having multiple processing units, each processing unit having a local cache memory associated therewith. For example, two or more spheres are used to bound an object so that each of the spheres is larger than a minimum necessary to bound the object, and a volume defined by an intersection between the shapes defines a smaller volume in which the object is bounded. The cells are divided into at least two different types of the individual cells, configured so that sound waves emitted by a first type of said different types of individual cells establishes a sound cancellation pattern with sound waves emitted by a second type of said different individual cells or an aggregation of different types of the individual cells. Therefore, a back lid cannot be opened, and the cam plate locks a power source lever, so that a power switch cannot be turned on. The method further includes determining an objective function for an optimization problem using the topology information and demands, and determining a solution to that specifies a network path for each demand. The hydrogen reacts with the sulfur oxides to form hydrogen sulfides thereby removing the sulfur oxides from the HC-SCR catalyst.