Floes structural parameters

The next problem is to find an expression for Asg. This entropy difference is a function of the particle volume fractions in the dispersion ( ) and in the floe (<(> ). As a first approximation, we assume that Ass is independent of the concentration and chain length of free polymer. This assumption is not necessarily true the floe structure, and thus < >f, may depend on the latter parameters because also the solvent chemical potential in the solution (affected by the presence of polymer) should be the same as that in the floe phase (determined by the high particle concentration). However, we assume that these effects will be small, and we take as a constant. 

In the course of further work on characterizing the MCC sols it was found that the CCC of a variety of salts varied both with the solids content and temperature. Investigation of these parameters forms the basis of the study. It will be shown that as a result of particle shape, concentration and surface characteristics, coagulation leads to a gel-like structure. On further addition of salt the coagulated gel-like structure aggregates into floes that are irreversible. In this paper, we outline the experimental parameters which lead to these phenomena and present some possible explanations. 

Accepting the elastic floe model as a reasonable description of the structured suspension, it is possible to calculate a few more parameters from the experimental results. For example C p may be calculatedfrom which, in turn, may be obtained from the plastic viscosity, ripj using the Mooney equation (23),... 

In this case, the oscillation is fixed (e.g., at 1 Hz) and the viscoelastic parameters are measured as a function of strain ampHtude. G, G and G" remain virtually constant up to a critical strain value, (this region is the linear viscoelastic region), but above G and G starts to fall, whereas G" starts to increase (this is the nonhnear region). The value of may be identified with the minimum strain above which the structure of the dispersion starts to break down (e.g., the breakdown of floes into smaller units and/or the breakdown of a structuring agent). 

The development of offshore exploration for oil and gas in the Arctic and Sub-Arctic regions has motivated interaction studies of ice floes and ice fields with offshore structures. Ice forces experienced by the structure depend on many parameters such as ice floe thickness, contact width of ice structure Interface, shape of the structure, strain rate in the ice at the contact zone, material characteristics of the ice, structure velocity at the contact zone (dependent on structure stiffness), temperature, etc. Random ice excitation can be nonstationary in frequency content or intensity or both. The excitation can... 

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