Dislocations in Elastic Solids; Bulk, Surface and Interfacial Waves in Anisotropic Elastic Media; Mechanics of Piezoelectric and Piezomagnetic Materials, Modeling of transport in fuel cell materials and of AFM usage to characterize charge distributions and impedance of fuel cell media. He is the author of over 125 technical articles concerned with dislocations and waves in anisotropic elastic and piezoelectric media.