Rheology

Question 1

The study of deformation and flow properties of matter

Answer 1

rheology

Question 2

(main components)
- resistance to flow
- property of liquids

Answer 2

viscosity

Question 3

(main components)
- stickiness or structure
- property of solids

Answer 3

elasticity

Question 4

newtonian systems

Answer 4

-shearing stress (F)
-rate of shear (G)
-fluidity
-kinematic viscosity

Question 5

force per unit area required to bring about a flow

Answer 5

Shearing Stress (F)

Question 6

Directly proportional to shearing stress

Answer 6

Rate of Shear (G)

Question 7

Coefficient of viscosity or VISCOSITY

Answer 7

η →Greek letter “eta” [ey-tuh]

Question 8

unit of viscosity

Answer 8

𝑔 / 𝑐𝑚 𝑠𝑒𝑐 𝑜𝑟 Poise (poiz)

Question 9

centipoise (cp)

Answer 9

0.01 poise

Question 10

Reciprocal of viscosity

Answer 10

• fluidity
• φ →Greek letter “phi” [fahy]
• φ = 𝟏 / 𝜼

Question 11

absolute viscosity divided by density of the liquid at specific temperature,
- 𝝂 = 𝜼 / 𝝆
- ν →Greek letter “nu” [nyoo]

Answer 11

kinematic viscosity

Question 12

unit of measurement for kinematic viscosity

Answer 12

stokes (s) or centistokes (cs)

Question 13

(temperature dependence of viscosity) for liquids: when temperature increases

Answer 13

viscosity decreases

Question 14

why do liquids and their viscosity act accordingly when it comes to their temperature?

Answer 14

due to decrease in intramolecular forces of attraction

Question 15

(temperature dependence of viscosity) for gases: when temperature increases

Answer 15

viscosity increases

Question 16

Examples are simple liquids, either pure chemicals or solutions, water

Answer 16

newtonian fluids

Question 17

viscosity of newtonian fluids is ________ on the rate of shear

Answer 17

independent

Question 18

Majority of fluid pharmaceutical products do not follow Newton’s law of flow.

Answer 18

non-newtonian systems

Question 19

non-newtonian systems are generally exhibited by:

Answer 19

• colloids
• emulsions
• suspensions
• ointments

Question 20

a non-newtonian fluid ________ when under stress or strain

Answer 20

changed its behavior

Question 21

(determination of rheologic properties)
- Capillary Viscometer
- Falling Sphere Viscometer

Answer 21

newtonian liquids

Question 22

(determination of rheologic properties)
- Rotational Viscometer
(1) Cup and Bob Viscometer
(2) Cone and Plate Viscometer

Answer 22

non-newtonian liquids

Question 23

The viscosity of a Newtonian liquid can be determined by measuring the time required for the liquid to pass between two marks as it flows by gravity through a vertical capillary tube.

Answer 23

capillary viscometer

Question 24

another name for capillary viscometer

Answer 24

ostwald viscometer

Question 25

A glass or steel ball rolls down an almost vertical glass tube containing the test liquid at a known constant temperature. The rate at which a ball of a particular density and diameter falls is an inverse function of the viscosity of the sample.

Answer 25

falling sphere viscometer

Question 26

another name for falling sphere viscometer

Answer 26

hoeppler viscometer

Question 27

the sample is sheared in the space between the outer wall of a bob and the inner wall of a cup into which the bob fits.

Answer 27

cup-and-bob viscometer

Question 28

rotating cup

Answer 28

couette type - macmichael viscometer

Question 29

rotating bob

Answer 29

searle type - brookfield and stoermer viscometer

Question 30

* the sample is placed at the center of the plate, which is then raised into position under the cone. * A variable-speed motor drives the cone, and the sample is sheared in the narrow gap between the stationary plate and the rotating cone.

Answer 30

CONE-AND-PLATE VISCOMETER

Question 31

another name for cone-and-plate viscometer

Answer 31

ferranti-shirley viscometer

Question 32

Exhibit both viscous fluidity and elastic solidity when undergoing deformation

Answer 32

viscoelasticity