Viscosity basic research

A special area of HP NMR in catalysis involves supercritical fluids, which have drawn substantial attention in both industrial applications and basic research [249, 254, 255]. Reactions in supercritical fluids involve only one phase, thereby circumventing the usual liquid/gas mixing problems that can occur in conventional solvents. Further advantages of these media concern their higher diffusivities and lower viscosities [219]. The most commonly used supercritical phase for metal-catalyzed processes is supercritical CO2 (SCCO2), due to its favorable properties [256-260], i. e., nontoxicity, availability, cost, environmental benefits, low critical temperature and moderate critical pressure, as well as facile separation of reactants, catalysts and products after the reaction. 

Fedoroff, "Basic Research Leading to the Development of Ideal Propellants. Preparation of Low Viscosity, High Nitrogen Nitrocellulose , PATR 1678 (Feb 1948)... 

There are few studies specifically designed to determine the effects of enzymes on the functionality of highly purified proteins. The need for basic research in this area is enormous. However, it is readily evident that functional properties such as solubility and viscosity of a purified protein can be altered drastically by proteolytic enzymes. 

The most widely used viscometers are based on measurements of the rate of elongation of a fiber of known dimensions under a known load. This method can be used for viscosities ranging from 10 to 10 Pa s. This method is also used for the determination of the Littleton softening and annealing reference points. Since the method requires formation of a long fiber for a specimen, it is well suited for many easily-worked commercial glasses, but difficulties in the formation of good fibers from many experimental compositions often limit the use of this method for basic research studies. 

While Maurice Huggins spent much of his career in industiy, he was more interested in basic research than in practical investigations. his major contributions to pol3nner science were related to entropy of mixing and the viscosity of dilute solutions. He died in California in December 1982. 

The anisotropic shear viscosity coefficients V2> 3 t]i2 have been determined only for a few liquid crystals. In contrast there have been many investigations of the shear viscosity coefficient under flow alignment. The reason for this might be that the effort required to determine. the anisotropic coefficients is greater by far. Viscosity coefficients determined under flow alignment are often used to estimate the switching times of liquid crystal displays. For basic research they are less important. 

H2d, is accordingly proportional to M2 and thus the viscosity increment proportional to M, i.e. eq. (1) is obtained. Staudin-ger s viscosity relation has exerted a great invluence on both experimental and theoretical research. As is well established, eq. (1) is not verified by either for the type of polymers under discussion here. The investigations resulting in this inclusion tend to confirm the basic concepts of macromolecular science mentioned at the beginning and thus may also be regarded as one of the first applications of these concepts. 

Ciystallization from solution is an important separation and purification process in a wide variety of industries. These range from basic materials such as sucrose, sodium chloride and fertilizer chemicals to pharmaceuticals, catalysts and specialty chemicals. The major purpose of crystallization processes is the production of a pure product. In practice however, a number of additional product specifications are often made. They may include such properties as the ciystd size distribution (or average size), bulk density, filterability, slurry viscosity, and dry solids flow properties. These properties depend on the crystal size distribution and crystal shape. The goal of crystallization research therefore, is to develop theories and techniques to allow control of purity, size distribution and shape of crystals. 

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