L1

Question 1

to describe the flow of liquids and the deformation of solids

Answer 1

Rheology

Question 2

is the study of the flow of the materials that behave in an interesting or unusual manner.

Answer 2

Rheology

Question 3

is an expression of the resistance of a fluid to flow

Answer 3

Viscosity

Question 4

involved in the mixing and flow of materials, their packaging into containers, and their removal prior to use, whether this is achieved by pouring from a bottle, extrusion from a tube, or passage
through a syringe needle.

Answer 4

Rheology

Question 5

can influence the selection of processing equipment used in its manufacture

Answer 5

Rheologic properties

Question 6

recognized the importance of rheology in pharmacy and
suggested its application in the formulation

Answer 6

Scott-Blair

Question 7

Scott-Blair analysis of the following pharmaceutical products:

Answer 7

• emulsions
• pastes
• suppositories
• tablet coatings

Question 8

Example of complex fluids

Answer 8

Foods
Biofluids
Personal care products
Electronic and optical materials
Pharmaceuticals

Question 9

change of the shape and the size of a body due to
applied forces (external forces and internal forces)

Answer 9

Deformation

Question 10

irreversible deformation (matter is not reverted to the original state when the force is removed)

Answer 10

Flow

Question 11

reversible deformation (matter is reverted to the original form after stress is removed)

Answer 11

Elasticity

Question 12

deformation in term of relative displacement of the particles
composing the body

Answer 12

Strain

Question 13

measure of internal forces acting within a (deformable) body

Answer 13

Stress

Question 14

deformation of a body in one direction only and having a given
perpendicular gradient

Answer 14

Shear

Question 15

Classification of Materials According to Types of Flow and Deformation

Answer 15

1. Newtonian Systems
2. Non-Newtonian Systems

Question 16

was the first to study flow properties of liquids in a quantitative way.

Answer 16

Newton

Question 17

He recognized that the higher the viscosity of a liquid, the greater is the force per unit area (shearing stress) required to produce a certain rate of shear.

Answer 17

Newton’s Law of Flow

Question 18

Ex. water, ethanol, acetone, glycerine, benzene

Answer 18

Newtonian flow

Question 19

Has linear relationship between shear rate and shear stress

Answer 19

Newtonian flow

Question 20

Constant viscosity with increasing rate of shear

Answer 20

Newtonian flow

Question 21

is the force per unit area required to required to
bring about flow.

Answer 21

Shearing stress

Question 22

Formula for shearing stress

Answer 22

F = F’ / A

Question 23

the difference of velocity
(dv) between two planes of liquid separated by an infinitesimal distance
(dr).

Answer 23

Rate of Shear (G) or Velocity Gradient

Question 24

Formula of Rate of Shear (G) or Velocity Gradient

Answer 24

G = dv/dr

Question 25

1 centinpoise is equal to ___ poise

Answer 25

0.01 poise

Question 26

reciprocal of viscosity

Answer 26

Fluidity(⌀)

Question 27

Is the absolute viscosity divided by the density of the liquid at a specific temperature

Answer 27

Kinematic Viscosity

Question 28

Shear Dependent Viscosity?

Answer 28

- plastic - pseudoplastic - dilatant

Question 29

Time Dependent Viscosity?

Answer 29

- thixotrophy - rheopexy - non newtonian sysytems

Question 30

The majority of fluid pharmaceutical products are not simple liquids and do not follow Newton's law of flow.

Answer 30

Non-Newtonian system

Question 31

Generally exhibited by liquid and solid heterogeneous dispersions such as colloidal solutions, emulsions, liquid suspensions, and ointments.

Answer 31

Non-newtonian systems

Question 32

Bingham bodies

Answer 32

Plastic

Question 33

fluid after agitation but resume their solid state after being undisturbed for a period of time.

Answer 33

Thixotrophy

Question 34

gel-sol transformation

Answer 34

Thixotrophy

Question 35

have the advantage that the particles remain in more or less permanent suspension during storage and yet when required for use, the paste are readily made fluid by tapping or shaking.

Answer 35

Thixotropic preparations

Question 36

Most apparent characteristic of a thixotropic system is the

Answer 36

hysteresis loop

Question 37

measure of thixotropic breakdown obtained by planimeter or suitable technique

Answer 37

Area of Hysteresis

Question 38

Represents an increase rather than a decrease in consistency on the down-curve

Answer 38

Negative Thixotropy/Antithixotropy

Question 39

are deflocculated and ordinarily contain greater than 50% by volume of solid dispersed phase

Answer 39

Dilatant systems

Question 40

have low solid content (1%-10%) and are flocculated.

Answer 40

Anti Thixotropy systems

Question 41

rare phenomenon in which the longer the fluid undergoes shearing forces, the higher the viscosity.

Answer 41

Rheopexy

Question 42

gel is the equilibrium form

Answer 42

Rheopectic system

Question 43

sol is the equilibrium form

Answer 43

Antithixotropic system

Question 44

The property of materials wherein this exhibit both the viscous properties of liquids as well as the elastic property of solids.

Answer 44

Viscoelasticity

Question 45

When materials are subjected to stress for a period of time they undergo slight deformation under the influence of the stress but once the stress is removed, they exhibit their behavior by returning to their original shape with little permanent deformation.

Answer 45

Viscoelasticity

Question 46

Application of Viscoelasticity

Answer 46

❖ Creams ❖ Lotions ❖ Ointments ❖ Suspensions ❖ Colloidal dispersions

Question 47

Determination of Rheologic Properties

Answer 47

I. Single-shear Rate Instrument II. Multipoint, Rotational Instruments

Question 48

Suitable for use only with Newtonian materials

Answer 48

Single-shear Rate Instrument

Question 49

Can be used both for Newtonian and non-Newtonian materials

Answer 49

Multipoint, Rotational Instruments

Question 50

Example of Single-shear Rate Instrument

Answer 50

a) Capillary Viscometer b) Falling-Sphere Viscometer

Question 51

Example of Multipoint, Rotational Instruments

Answer 51

a) Cup-and-bob Viscometer b) Cone-and-Plate Viscometer

Question 52

Shear thinning systems

Answer 52

Pseudoplastic

Question 53

Shear thickening system

Answer 53

Dilatant

Question 54

Who suggested Rheology

Answer 54

Bingham and crawford