Attitude stabilization of spacecraft using magnetorqers can be achieved by a proportional-derivative-like control algorithm. The gains of this algorithm are usually determined by using a trial-and-error approach within the large search space of the possible values of the gains. However, when finding the gains in this manner, only a small portion of the search space is actually explored. We prop...

We study in this paper the problem of robust and perfect tracking for discrete-time linear multivariable systems. By robust and perfect tracking, we mean the ability of a controller to track a given reference signal with arbitrarily small settling time in the face of external disturbances and initial conditions. A set of necessary and su$cient conditions under which the proposed problem is solv...

Chitosan, a cationic carbohydrate polymer manufactured from chitin in shrimp and crab wastes, coagulated suspended solids in cheese whey as effectively or more so than ten commercial synthetic polymers. Concentrations of suspended solids after settling were reduced over 90% by coagulation at pH 6.0 with a ratio of chitosan to suspended solids of 2.15% (1:46.5). The yield of coagulated solids wa...