Cylindrical Design: Comments

• Irrigation Tubes

  Perforated tubes replaced uniformly porous tubes.
  Turbulent mixing increased rate of pH change.

• Terminations

  Smooth stress gradients were achieved by gradually
  increasing saponification from terminations to mid region.

• Differential Expansion

  Variable expansion/contraction rate increased stress failures.

• Fluid Flow

  Unquided and uneven fluid flow through the fiber
  bundles produced non-uniform stress.

• Mechanical Model

  Quantitative model of gel, fluid delivery, and mechanical
  systems aided subsequent design.

• Hysteresis

  Hysteretic behavior of the amphoteric gel, poly(acrylonitrile) (PAN) requires substantial pH changes.