Balance rheometer

Binding, D. M., Davies, J. M., and Walters, K., Elastico-viscous squeeze films 111. The torsional balance rheometer, /. Non-Newtonian Fluid Mech., 1, 277 (1976). Zahorski, S., scoelastic properties in plane squeeze-film flows,/. Non-Newtonian Fluid Meek, 4, 217 (1978). 

Other eccentric rotating geometries (a) tilted rotating hemispheres (also called balance rheometer), (b) eccentric rotating cylinders, and (c) tilted rotating cone and plate. 

Several other eccentric geometries have been described. Three of them are shown in Figure 5.7.5. Kepes (1968) and Kaelble (1969) developed tilted rotating hemispheres also known as the Kepes balance rheometer. Figure 5.7,3 shows that this rheometer can measure li and G data accurately. ... 

The Kepes balance rheometer is another device that determines dynamic properties in steady rotation. Material is confined between concentric hemispheres whose axes of rotation form an angle 6. Both hemispheres rotate with the same angular velocity cd. Ro — Rf = 8 Ri and 6 is small. 

Other devices have been developed that operate along similar lines. The so-called balance rheometer confines a test fluid between two concentric hemispheres that rotate at the same rate but whose axes of rotation are inclined at an angle to one another. Similarly, cone-and-plate geometry, in which the axis of the cone is not perpendicular to the plate, and Couette (cup-and-bob) geometry, with the bob not centered in the cup can also be used to obtain dynamic data. These devices are analyzed by Walters. Dynamic tensile properties can be obtained for relatively rigid materials by subjecting a rotating cylindrical rod to a cantilever deflection. ... 

Naumann CA, Brooks CF, Fuller GG, Knoll W, Frank CW (1999) Viscoelastic properties of lipopolymers at the air-water interface a combined interfacial stress rheometer and film balance study. Langmuir 15 7752-7761... 

Standard mud laboratory equipment was utilized in this research. Mud density was determined by a Baroid mud balance. Mud rheology was determined by a Bariod variable-speed electronic rheometer and a standard filter press. Presently, there Is no API approved method for determining abrasiveness of a... 

An alternative procedure, to ensure no external force is applied to the powder bed by the vaned paddle, is to place the compacted sample on a balance and when the paddle is immersed in the powder to raise the vaned head slowly until the balance reading is zero. This dynamic method of bulk powder characterisation is allied to the rheological method for measurement of the viscosity of non-Newtonian fluids and suspensions. Commercial instruments based on the WSL cohesion tester are now available in the form of the FT4 Powder Rheometer (Freeman Technology) and the Stable Micro Systems Powder Flow Analyser (Stable Micro Systems). 

Solution. Based on the description of the cone-and-plate rheometer in Section 3.3 we can consider the flow to be as shown in Figure 5.4. Based on the dimensions given, the height, H, at the edge is 0.125 cm. An energy balance is performed on the slab of thickness Ay and unit width. It is assumed that heat is generated by viscous dissipation, which is the conversion of mechanical energy into heat. The viscous dissipation per unit volume is... 

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