Other studies are being carried out to identify velocity patterns within axially rotating cylindrical containers using laser doppler velocimetry techniques. Rheological studies in collaboration with Dr. Juming Tang have concentrated on the mechanical properties of calcium, sodium and potassium-crosslinked gellan gels. Molded specimens have been tested in torsion, tension and compression experiments. Shear stresses at failure have been found to increase with ion concentration up to a critical value then decrease with further increases in concentration. Shear strain at failure decreases with both polymer and ion concentration below a critical value for ion concentration, above which it converges at a constant value.
Properties are also related to ion size, with magnesium crosslinked gels weaker than calcium ones.
In order studies on whey protein gels, we have included polystyrene microspheres to monodisperse inclusions for a range of sizes and volume fractions in order to measure effects on viscoelasticity and failure properties.