Elongational thickening

PO Edema with concurrent weight gain, hypertrichosis (elongation, thickening, increased pigmentation of fine body hair develops in 80% of patients within 3-6 wk after beginning therapy)... 

Unlike the shear viscosity, the first coefficient fii for the elongational viscosity starts from a term that is independent of any derivatives of hence giving a large positive contribution. It is therefore clear that our network has a tendency to elongational thickening irrespective of the detailed form of /3(r). 

For a constant recombination rate a, a similar calculation was done by Fuller et al. [47] to study the effect of entanglements in the polymer melts. They found that the number density of entanglement junctions is a decreasing function of the flow rate, and that shear thinning and elongational thickening are two major characteristics shared by all transient networks that fall into this category. 

More elongated devices are used for slurry thickening whilst those of more squat aspect ratio devices are suitable for product classification by size, as in fines-destruction circuits. The pressure drop in a hydrocyclone varies with the feed rate raised to a power between 2 and 3.3. The cut size is a weak function of pressure drop, varying with for dilute feeds. Large pressure drops are... 

Changes in wall architecture occur during isodiametric cell expansion, cell elongation, and the thickening of a growing wall to its mature thickness, and so it is important to define whether the synthesis and secretion of particular cell-wall molecules correlates with differentiation events or with general cell expansion. Ceils are stimulated into producing wall polysaccharides upon subculture, so we used a non-inductive medium, in which the cells only expand, for comparison with inductive medium at all times. 

Myocardial hypertrophy The heart increases in size, and the chambers dilate. Initially, stretching of the heart muscle leads to a stronger contraction of the heart. However, excessive elongation of the fibers results in weaker contractions. This type of failure is termed systolic failure and is a result of a ventricle unable to pump effectively. Less commonly, patients with CHF may have diastolic dysfunction—a term applied when the ventricles ability to relax and accept blood is impaired by structural changes, such as hypertrophy. The thickening of the ventricular wall and subsequent decrease in ventricular volume decreases the ability of heart muscle to relax. In this case, the ventricle does not fill adequately, and the inadequacy of cardiac output is termed diastolic heart failure. 

Both effects have important consequences for processing of polymers. The thickening of the elongational viscosity stabilizes filaments and films of polymers. The thinning of the shear viscosity causes many problems in mixing and dispersion in polymer products, because flow then mainly occurs in high shear regions and not elsewhere. 

All these fluids can show the other non-Newtonian properties that we have already discussed elastic properties, normal stresses, and thickening or thirming of the elongational viscosity. In addition, they can also have a yield stress or a time-dependent viscosity. 

Inhibition of cell division, lack of spindle formation, inhibition of protein synthesis, increased cell size, radial elongation of cells, polyploid nuclei chromosome contraction, cell wall thickening. 

One may try to avoid the problem by the use of the upper-convected derivative, which ensures the coincidence of the principal axes of stress and strain. But doing that, it appears that any kinetics based on the stress amplitude is improper, since materials which exhibits thickening behaviour in elongation are, to the contrary, shear-thinning. Consequently no unique dependence can be expected for these two kinematics. The determination of a single set of parameters in various flows in then bound to be a compromise. 

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