When blood is taken out of the body for processing into an extracorporeal device, a major concern is that the level of shear stress to which the blood is exposed should be less than a critical level (roughly 1000 dyne/cm2 ). For exposure to shear stress levels higher than this, lysis of the red blood cells can occur, together with platelet activation and initiation of the clotting process. Consider the flow of blood through a device that has a set of parallel tubes each with a diameter of 1mm and a length of 10 cm. What is the maximum pressure drop that should be used for such a device if the highest shear levels in the device occur in these tubes? State your assumptions.