A dynamic-angle spinning probe for solid-state nuclear magnetic resonance is acquired tosupport research in engineering. The initial use of the probe will be the characterization of amorphous silia-alumina acid catalysts. Model catalysts with the acid function restricted to the surface are prepared and the density and strength of acid sites aremeasured by a conbination of base adosrption andacid- catalyzed reactions. The activity of tehsilica-aluminas is correlated with the structure determined by dunamic-angle aluninum-27 nuclear magnetic resonance. Acid catalysts are widely used industrially. Because of their low cost, applications can be expected to increase in fuels refinement, chemicals production, and environmental control. However, a better understanding of their behavior is necessary to design control systems for optimum conversions.