4. a researcher is testing a polymer with a known poisson’s ratio of 0.375 as a vascular graft. a 10 cm tube of the polymer with an outer diameter of 0.5 cm and a thickness of 0.2 cm is subject to conditions similar to blood flow and the length of the graft decreases by 10%. a. what is the inner diameter dimension when the graft is compressed? b. is this polymer an isotropic or anisotropic material?

Amixture of slurry and mud is to be pumped through a horizontal pipe of diameter 500 mm. the fluid behaves as a bingham plastic with a yield stress of 30 pa and viscosity 0.04 pa. s. describe the effects of the shear stress through a transverse section of the pipe by plotting the variation in shear stress and velocity profile: (i) just before the slurry starts to move (ii) as the slurry flows when the pressure gradient is double that in part (i)