1. Professor, Faculty of Civil Engineering and Services, Technical Univ. of Gheorghe Asachi Iasi, B-dul D., Mangeron 43, Iasi 700050, Romania.
2. Associate Professor, Faculty of Chemical Engineering and Environmental Protection, Technical Univ. of Gheorghe Asachi Iasi, B-dul D., Mangeron 73, Iasi 700050, Romania.
3. Lecturer, Faculty of Chemical Engineering and Environmental Protection, Technical Univ. of Gheorghe Asachi Iasi, B-dul D., Mangeron 73, Iasi 700050, Romania (corresponding author).