A seminar by Prof. Leonard A. Dissado - Emeritus Professor, University of Leicester (UK)
Date: 28 MAY 2019 from 10:00 to 11:30
Event location: Aula 5C - Chimica Industriale - Viale Risorgimento, 4 Bologna
Type: Seminar
A dielectric is defined as a material that when placed in an electric field polarises rather than conducts. The basic physical features of dielectrics that give rise to this behaviour are briefly described, and their practical importance in terms of energy storage outlined. The other major application of dielectric response is that of an analytical tool yielding information on the density of dipoles free to adapt their orientation in an electric field and the rate at which they do this, both of which are dependent upon the material chemistry and morphology. The fundamental equations governing the frequency-dependent susceptibility are presented and compared to experiment with a glass-forming material and a ferroelectric used as examples. It is pointed out that in typical experiments more than one process may contribute to the observed response, and that the combination may either correspond to a parallel combination (additive) or a series combination (addition of inverses). The lecture finishes with examples of a series combination using the dielectric response of biological tissues for which the basic feature is the limited displacement of ions rather than dipole relaxation.
Leonard A Dissado, BSc, PhD, DSc, FIEEE is a Professor Emeritus with the University of Leicester UK. He is the co-author of the book Electrical degradation and Breakdown in Polymers and has published more than 330 papers, of which more than 250 are on electrical degradation and dielectric spectroscopy. He has been a visiting professor at universities in Australia, Italy, France, Japan, China, and the USA. He has given numerous invited lectures, including the E.O.Forster (ICSD 2001) and the Whitehead (CEIDP 2002) memorial lectures, and received the award of Doctuer Honoris Cause from the University of Toulouse, Honorary Professor from Xi’an Jiaotong University China, and the Dakin Award of the IEEE DEIS. He is currently a member of the DEIS Publications Committee.