Rheology

Question 1

The study of flow, addresses the viscosity characteristics of powders, fluids, and semisolids

Answer 1

Rheology

Question 2

Refers to resistance to flow or thickness

Answer 2

Viscosity

Question 3

Refers to stickiness or structure

Answer 3

Elasticity

Question 4

Refers to when materials exhibit both elastic behavior and viscous flow

Answer 4

Viscoelasticity

Question 5

Basic unit of viscosity

Answer 5

Poise

Question 6

1 poise = _____ centipoise

Answer 6

100 centipoise

Question 7

Is characterized by constant viscosity, regardless of the shear rates applied

Answer 7

Newtonian flow

Question 8

Is characterized by a change in viscosity characteristics with increasing shear rates

Answer 8

Non-Newtonian flow

Question 9

Does not begin until a shearing stress corresponding to a certain yield value is exceeded

Answer 9

Plastic flow (Bingham bodies)

Question 10

These substances begin flow when a shearing stress is applied; therefore, they exhibit no yield value

Answer 10

Pseudoplastic

Question 11

Are observed in systems that deform and flow; instantaneously with applied stress; viscosity decreases at increasing shear stress

Answer 11

Plastic flow (Shear-thinning)

Question 12

Increase in volume when sheared; and the viscosity increases with increasing shear rate

Answer 12

Dilatant flow (Shear-thickening)

Question 13

Is a reversible gel-sol formation with no change in volume or temperature; a type of non-Newtonian flow

Answer 13

Thixotropy

Question 14

Represents an increase in consistency with increased time of shear

Answer 14

Negative thixotropy/Antithixotropy

Question 15

A phenomenon in which a solid forms a gel more readily when gently shaken or otherwise sheared

Answer 15

Rheopexy

Question 16

Is the taking up of a certain amount of liquid without a measurable increase in volume

Answer 16

Imbibition

Question 17

Is the taking up of a liquid by a gel with an increase in volume

Answer 17

Swelling

Question 18

Occurs when the interaction between particles of the dispersed phase becomes so great that on standing, the dispersing medium is squeezed out in droplets and the gel shrinks

Answer 18

Syneresis

Question 19

Is formed when the liquid is removed from a gel and only the framework remains

Answer 19

Xerogel