Rheological investigation

Rheological investigations of asphalts by Traxler and associates (123,124), Lee et al. (51), Pfeiffer and Van Doormaal (94), Thelen (117), Mack (60), and others show the following to be characteristic colloidal properties. 

The preceding paragraphs furnish the basic elements constituting the starting point for rheological investigations of suspensions. Subsequent analysis based thereon has a two-fold thrust (i) Determination of the (statistical)... 

The sedimentation results obtained with the structured suspensions, are consistent with the predictions from rheological investigations. In the absence of any bentonite clay, the pesticidal suspension exhibits Newtonian behaviour with unmeasurable yield value, modulus or residual viscosity. In this case the particles are free to settle individually under gravity forming a dilatant sediment or clay. On the other hand, at bentonite concentrations above the gel point (> 30 g dm the non-Newtonian behaviour of the suspensions and in particular their viscoelastic behaviour results from the formation of a "three-dimensional" network, which elastically supports the total mass. After 21 weeks standing in 100 ml measuring cylinders, no separation was observed when the bentonite concentration was >37.5 g dm corresponding to a modulus > 60 Nm. Clearly the modulus value required to support the mass of the suspension depends on the density difference between particle and medium. 

The results of rheological investigation of the kinetics of gelation of physical nature, taking place as a result of phase sepiuation of the corresponding polymer... 

Richardson, P. H., Clark, A. H., Russell, A. L., Aymard, P. and Norton, I. T. 1999. Galactomannan gelation A thermal and rheological investigation analyzed using the cascade model. Macromolecules 32(5) 1519-1527. 

Kocevar-Nared, J. Kristi, J. Smid-Korbar, J. Comparative rheological investigation of crude gastric mucin and natural gastric mucus. Biomaterials 1997, 18 (9), 677-681. 

The American Society of Rheology, which was founded in 1929, has defined rheology as the science of deformation and flow of matter. Deformation describes the change of matter in terms of shape or volume, or both. If the changes due to deformation are at least partly nonreversible, then matter flows. The full spectrum of possible types of deformation of liquid or solid matter is illustrated in Fig. 1. The gaseous state is usually not part of rheological investigations. 

Typical modern rheological investigations do not consider Newtonian liquids in the sense of the Navier-Stokes model or fully elastic solids, but are concerned with the behavior of materials between these two extremes.In the pharmaceutical sciences, however, Newtonian behavior and its characterization are of interest, and methodology and equipment are described in various pharmacopeias to provide standards for the quality of pharmaceutical materials. 

Lipid monolayers have also been studied by surface rheology, which yields complementary information. The present author is not aware of systematic studies in which optical and rheological investigations have been ceirrled out on one cuid the same sample under the same conditions. 

Zugenmaier, P. Haurand, P. Structural and rheological investigations on the lyotropic, liquid-crystalline system 0-ethylcellulose-glacial acetic acid-dichloroacetic acid. Carbohydr. Res. 1987, 160, 369-380. 

Studies of the equilibrium and dynamic adsorption behaviour of biopolymers at liquid interfaces in combination with thermodynamic and kinetic models allow us to draw conclusions about the structure of the interfacial layer. Additional information can be obtained from rheological investigations, both under shear and dilational deformations. 

No additional salt-dependent swelling measurements or rheological investigations were carried out on these gels. The following trends can be inferred ... 

The rheological investigations were conducted using a Controlled-Stress TA Instruments AR-1000 Advanced Rheometer. The temperature of the system was maintained at 30 °C throughout the experiments. 

Rheological investigations [7] of the regular polystirene starts which are differed by a number of the rays (6, 12 and 22) and by the structure of the branching center (one or two covalently connected molecules of... 

M. Horton, H. Hong, and P. Smith, A rheological investigation of carbon nanotube grease, in preparation. 

Clemens F., Corbari R., Graule T Preparation and rheological investigations on thermoplastic Zr02 pastes . Materials Week 2000, 25.-28.09.2000... 

Ti02 H2O TX-IOO /decane/water C (TIPO addition) Rheological investigation of sol-to-gel transition [90]. 

Fig. 31. The ARES rheometer was used for rheological investigations (geometry of the measuring device conus-plate diameter d=25 mm angle a=0.1 rad)...

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