学术报告通知

题目：Strength Distribution of Biological Aggregates
报告人：Prof. Ramin Farnood （简介见后）
单位：Department of Chemical Engineering and Applied Chemistry, University of Toronto

时间：7月5日下午3～5点
地点：环境系系馆一会

报告内容介绍：
Better understanding of the mechanical strength of microbial aggregates helps to improve the design and operation of the biological treatment systems. The existing methods for evaluating the shear strength of biological aggregates are based on subjecting the sample to a non-homogeneous turbulent flow condition and monitoring the reduction in the bio-aggregate size distribution. However, due to the non-uniform shear rate distribution in the flow field, these techniques provide only an approximation of the average strength. Therefore, the objective of the present study is to overcome this limitation by studying the breakage of biological aggregates under well-defined hydrodynamic conditions and to determine their shear strength distribution as a function of their size and age. A Couette flow cell consisting of two concentric cylinders with a 2 mm gap was developed to create a well-controlled shear conditions. The shear stress can be adjusted by changing the rotational speed of the inner cylinder using a variable drive. The shear strength distribution of bio-aggregates was estimated by measuring the changes in their size distribution after exposing the sample to various shear stress levels. Results obtained for different sizes fractions indicate that larger size fractions have a larger fraction of weak aggregates.
作者介绍：
Professor Ramin Farnood is an associate professor at the Department of Chemical Engineering and Applied Chemistry and Associate Director of Pulp & Paper Centre at the University of Toronto. He is the principal investigator of Surface Science Consortium, an international University-Industry collaborative research program. Professor Farnood received his BASc and MASc. in chemical engineering from Sharif University of Technology in Tehran, Iran, and a Ph.D. in chemical engineering from the University of Toronto. Professor Farnood’s research interests include surface science and environmental engineering. In particular, experimental and theoretical studies in interaction of light with paper surface, compression of fibre networks, bio- and photoactive media, digital print quality, statistical geometry, characterization of stochastic materials and surfaces, surface structure of paper, paper formation and fibre flocculation, mechanical properties of flocs, effect of bioflocculation on ultraviolet disinfection, photocatalytic and sonolytic destruction of microbial and chemical contaminants in water and wastewater, and characterization of suspended particles in wastewater.