[1] Institute of Chemical Technology and Engineering Poznan University of Technology pl. M. Sklodowskiej-Curie 2 60-965 Poznan,
[2] Poland e-mail: teofil.jesionowski@put.poznan.pl Tel.: +48-61-6653626 Fax: +48-61-6653649,undefined
[3] Institute of Material Technology Poznan University of Technology ul. Piotrowo 3,undefined
[4] 61-138 Poznan,undefined
[5] Poland,undefined