报告题目：Desiccation Crack Patterns in Clay Samples Dried in an Electric Field
报 告 人：Prof. Sujata Tarafdar
所在单位：Jadavpur University, India
主 持 人：臧渡洋 副教授
We study crack patterns formed in drying samples of a synthetic clay – Laponite placed in an electric field. The patterns depend strongly on the direction and strength of the field. For DC (direct current) fields the patterns can be explained using a simple spring network model. Preliminary results for an AC (alternating current) field are presented as well. We also study cracks in small droplets when the electric field is applied for a finite time interval. Scaling laws can be formulated connecting the time of appearance of cracks and the number of cracks, with the time duration and strength of the applied DC field.
报告题目：Pattern Formation in Drying Droplets of Complex Fluids Containing Salt
A droplet of complex fluid containing sodium chloride forms a variety of patterns during drying depending on the composition of the fluid and the concentration of salt. We show that for only salt and water, the coffee stain effect is found, whereas with gelatinized starch, carboxy-methyl cellulose or gelatin the salt crystallizes in different forms like – regular crystals, hopper crystals, dendrites or multi-fractal patterns.