Patterns Formation in Drying Drops of Blood

The drying of a drop of human blood exhibits coupled physical mechanisms, such as Marangoni flow, evaporation and wettability. The final stage of a whole blood drop evaporation reveals regular patterns with a good reproducibility for a healthy person. Other experiments on anaemic and hyperlipidemic people were performed, and different patterns were revealed. The flow motion inside the blood drop is observed and analyzed with the use of a digital camera: the influence of the red blood cells (RBCs) motion is revealed at the drop periphery as well as its consequences on the final stage of drying. The mechanisms which lead to the final pattern of the dried blood drops are presented and explained on the basis of fluid mechanics in conjunction with the principles of haematology. The blood drop evaporation process is evidenced to be driven only by Marangoni flow. The same axisymetric pattern formation is observed, and can be forecast for different blood drop diameters. The evaporation mass flux can be predicted with a good agreement, assuming only the knowledge of the colloids mass concentration.Comment: 1 page + conference APS 2011 (1 movie for the gallery + 1 movie for ArXiv

Mars Rover - URC

The Rover’s key design components that will allow it to overcome the tasks in the competition are the suspension, differential, and motors. The suspension was designed to overcome a 60 cm tall flat vertical face without tipping or falling back on itself. The suspension was run through a SolidWorks simulation and numerous iterations to help in testing the suspension’s limitations. This will be especially useful in the competition’s terrain traversal task, and allow us to overcome numerous obstacles