COMMISSION * * OF THE EUROPEAN COMMUNITIES ISSN 0014-2352 GURU ABSTRACTS Scientific and technical publications from Community-funded research and development VOL. 31 N° 5/1993 ABSTRACTS : PUBLICATIONS 31/716-31/961 EURO ABSTRACTS is compi leti by the EABS (RTD-Publications). lhe on-line version of Euroabstracts, is accessible free of charge through ECHO Commission of the European Communities (European Commission Host Organization). For information, please contact : ECHO Customer Service, Airport Centre, DGXIII 'Information Technologies and Industries, and 5 rue Höhenhof, Luxembourg-Senningerberg Telecommunications'' in association with © ECSC-EEC-EAEC. Brussels-Luxembourg. 1993. Reproduction is authorized, except for commercial purposes, ECOTEC Research and Consulting Ltd provided the source is acknowledged. Legal Notice: and published by the Neither the Commission of the European Communities nor any person acting on behalf of the Commission is responsible for the use Office for Official Publications of the European which might be made of the following information. Communities EURO ABSTRACTS The abstracting journal of scientific and technical publications of the Commission of the European Communities Vol.