False body

Thus, equation 3.127, which includes three parameters, is effectively a combination of equations 3.121 and 3.125. It is sometimes called the generalised Bingham equation or Herschel -Bulkley equation, and the fluids are sometimes referred to as having/n/re body. Figures 3.30 and 3.31 show shear stress and apparent viscosity, respectively, for Bingham plastic and false body fluids, using linear coordinates. 

Figure 3.30. Shear stress-shear rate data for Bingham-plastic and false-body fluids using linear scale axes...

P.P.S. system 3. 5 Fahrenheit units 3 False body fluids 112 Fanno lines 172 Fans 344... 

The products of starch cooking with retention are similar to those obtained by dispersion with excess steam. Retention of starch paste for several minutes under pressure requires that all steam is condensed otherwise false body of uncondensed steam will shorten the retention. Jet cooking with retention is practiced for on-site chemical starch modification. 

Another technique for the preparation of a stable suspension is based on the concept of the structured vehicle, in which the viscosity of the preparation, under static conditions of very low shear, on storage approaches infinity. The vehicle is said to behave like a false body that is able to maintain the suspended particles in a state of more or less permanent suspension. 

An emulsion base or a waxy-type self-emulsifier to develop structure or false body in suspension... 

Deaeration of product may be helpful to avoid development of false body on storage. Use of the Kaopolite 1168 gives more aggressive cleaning and polishing action to the formulation. SOURCE Kaopolite, Inc. Suggested Formulations... 

The term false body has been introduced to describe the thixotropic behaviour of viscoplastic materials. Although the thixotropy is associated with the build-up of structure at rest and breakdown of structure under shear, viscoplastic materials do not lose their solid-like properties completely and can still exhibit a yield stress, though this is usually less than the original value of the virgin sample which is regained (if at all) only after a long recovery period. 

False body n. Thixotropic flow property of a suspension or dispersion. When a composition thins down on stirring and builds up on standing it is said to exhibit false body. The term false body is also used in practice for buttery materials, which are characterized by a relatively low viscosity and high yield value. 

Also called false body and shear thinning. 

Thixotropic adj (1) A liquid or dispersion that exhibits a reduction in viscosity with time at constant shear stress, opposite effect is rheopectic (not to be confused with pseudoplastic, reduction of viscosity with shear stress). (2) A term that describe full-bodies material which undergoes a reduction in viscosity when shaken, stirred, or otherwise mechanically disturbed and which readily recovers the original full-bodied condition on standing. See Body False Body. 

The Metzner-Otto relationship, eq. (6-17), does not apply for other non-Newtonian fluids, such as shear thickening finids, Bingham plastics, and false body fluids. In these finids, shear rates are highly localized aronnd the impeller blade, with the rest of the tank stagnant. The relationship does not apply in highly turbulent flow as well. 

It is uncertain whether thixotropy is of perfectly general occurrence in any gelling system. It looks indeed as if this might be the case, with the restriction that there arc systems (especially the coarser ones) with negligible setting time, which is distinguished from the usual thixotropy with finite setting time by the name false body ... 

Van Selms and Kruyt applied the principle of the rolling sphere viscometer (Hoppler viscometer) to thixotropic or rather to false body systems. The method allows one to obtain D-t curves though not on an absolute scale. Consequently it gives a measure for the gel strength and if the measurements are repeated after different waiting times, also for the rate of solidification. 

Paints and printing inks arc usually thixotropic. If the pigment were completely stabilized on standing it would form a very compact sediment, which is not easily redispersed. Moreover, after brushing the paint on a vertical surface, it would have a tendency to flow off. On the other hand of course, the system should be capable of being brushed out and therefore behave like a liquid. Its time of solidification should be just long enough to allov/ the strokes of the brush to be levelled out. A time of solidification zero is an undesirable property in a paint (hence the name false body for this property). 

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