C1-Emulsion

Question 1

Multi-Homo composition

Answer 1

two stirring elements ( anchor stirrer, spiral stirrer and a homogeniter

Question 2

anchor stirrer

Answer 2

equipped with two scraping arms

Question 3

which flow does the anchor stirrer creats?

Answer 3

tangential flow inside the vessel

vigorous radial mixing of materials

Question 4

spiral stirrerr

Answer 4

axial mixing of matrial and efficient vetical heat transfer

Question 5

homogenizer

Answer 5

it is installed and operated independently of the two stirring elements

Question 6

on what does the function of homogenzier based

Answer 6

rotor-stator principle

Question 7

what’s the importance of vigorous radial mixer?

Answer 7

a strong suction force draws the material from th vessel into the whirl chamber of the homogenizer

Question 8

when does the actual homogenization process takes place?

Answer 8

as the materials are pushed to the outside through the gap space between the rotor and stator

Question 9

Stephan composition?

Answer 9

one stirring element, which is the centrally rotating knife

Question 10

what are the movements of the centrally rotating knife?

Answer 10

radial and axial movements

Question 11

Ultra-turrax is based on?

Answer 11

rotor stator principle

Question 12

what’s the main different between the ultra-turrax and the multi-homo

Answer 12

ultra-turrax has a higher circumferential speed

Question 13

movement of the ultra-turrax

Answer 13

frequency shear, mechanical impact, collision, hydrodynamic potential gradients and turbulent fluid movements

Question 14

Bernoulli equation and cavitation

Answer 14

it states that the total energy of a flowing fluid

Question 15

what’s the bernoulli effect?

Answer 15

an increase in the flowing speed of a fluid (increase in kinetic energy) will be accompanied by a decrease in it static pressure (decrease pressure energy)

Question 16

what’s the resulting effect of the bernoulli effect

Answer 16

the phenomenon of cavitation

Question 17

what happend when the local pressure inside the gap area drops the vapor pressure

Answer 17

the liquid vaporizes and forms gas bubbles

Question 18

what happend after exiting?

Answer 18

the static pressure of the liquid increases and surpasses the vapor pressure, gas bubbles will violently implode

Question 19

what is the results of the implosions?

Answer 19

it leads to cavitation fragmentation , helps to break down liquid droplets

Question 20

high pressure homogenizer

Answer 20

primary function of this device is to homogenize and not to generate an emlsion from starting materials

Question 21

requirement of the HPH

Answer 21

has to be pre-emulsified mixture

Question 22

three major types of force in the HPH

Answer 22

fragmentation, cavitation, shear and turbulence

Question 23

cavitation fragmentation

Answer 23

pressure outside the gap is higher than the vapor pressure, whereas the pressure inside the gap is smaller,

Question 24

shear fragmentation

Answer 24

the tiny gap disrupts movement of the fliud and gives rise to a high shear force

Question 25

tubulence fragmentation

Answer 25

when existing the gap, the liquid forms a jet and the disintegration of this jet leads to small eddies

Question 26

two main parameter of the HPH?

Answer 26

homogenization pressure and the number of homogenization cycles

Question 27

what is the quantification of the laser diffraction with droplet size of emulsions

Answer 27

the droplet size is directly proportional to the intensity of light scattered by a droplet and inversely proportional to the angle of the laser beam

Question 28

how is the DSD measured in emsulsions?

Answer 28

Laser differecation analysis, by measuring the angular variation in intensity of light scattered as a laser beam passes through a sample

Question 29

how are smaller droplets in emulsions generated?

Answer 29

by using equipment with high mechanical energy, becuase to a certain extent smaler droplets can be generated

Question 30

why are emulsion just meta-stable and how do you achieve the meta stable state?

Answer 30

With a emulsifier, the emulsions can be stabilizied kinetically, refereing to as a meta stable state

Question 31

how can the particle velocity be decrease?

Answer 31

accoring to the stokes' law, | reduction of the particle size or increase the viscosity of the external phase

Question 32

defination of emulsion?

Answer 32

disperse system of two immiscible liquid

Question 33

continental method?

Answer 33

emulsifier is tured into a suspension by dispersing it in the internal phase then adding of the external pahse english method: emulsifier dissolved in the external phase

Question 34

what is responsible for the formation of droplet using emulsion divices?

Answer 34

solely on the mechanical energy input, which will lead to the phase inversion

Question 35

opaque and translucent occure with which equipment?

Answer 35

stephan translucent and multi-homo, Ultra Turrax and homogenizer opaque

Question 36

transulcent is an indication for?

Answer 36

creaming

Question 37

meaurement of the dropelt size of an transulcent and opaque system?

Answer 37

light is less likely to be scattered in a transulcent systme compared to the opque system

Question 38

why was autoclave carried out?

Answer 38

for sterilization at 121°C for 15 min at 2 bar

Question 39

why do we have an entlargment of droplets after autoclave?

Answer 39

Due to decrease of the viscosity, resulating to an increase of the creaming rate increase of the particle velosity

Question 40

what is the critical micelle concentration?

Answer 40

it is the limit at which a larger amount of emulsifer may futher lower the interfacial energy, thefore delay creaming

Question 41

which model can be used in a FFD and CCD?

Answer 41

``` a linear model for FFD quadratic correlations (CCD) ```

Question 42

CCd consist of ?

Answer 42

FFC, central point and star points

Question 43

rotatable design?

Answer 43

give very narrow confidence intervalts, depends on the vector length but not direction

Question 44

orthogonality?

Answer 44

prevents collinearity by an independent estimation of the coeefficient

Question 45

why is rotation more important than othogonality

Answer 45

becuase the design can be easily transofrmed into an orthogonal design by addition of runs, but not the other way around

Question 46

equation for rotation

Answer 46

do you know it?

Question 47

equation for total numbers of runs for oth

Answer 47

do you know it?

Question 48

equation forstar points?

Answer 48

do you know it?

Question 49

Q2 is?

Answer 49

it takes the ability of the model to predit values into account

Question 50

what are gels?

Answer 50

liquid immobilized by a suitbale gelling agent

Question 51

gels properties?

Answer 51

spreading properties under shear stress and great elastic pressure

Question 52

what's the critical property of gels?

Answer 52

yield point

Question 53

behaviour of a viscous fluid happend when?

Answer 53

when the applied shear stress is higher than the yield point

Question 54

below the yield point?

Answer 54

elastic solid

Question 55

what's the immobilizing mechanism if the gel?

Answer 55

it is it's swelling in water to reduce, increasing the system's viscosity

Question 56

example for a gelling agent?

Answer 56

carbomers, high molecular-weight polyacrylic acid slight cross-linked with polyalkene ethers of surga or polyalcohols

Question 57

what happend water water ia added to carbomers?

Answer 57

it takeup water to sweel and uncoil it polymer chains

Question 58

the addition of base to the carbomers?

Answer 58

chains will reple each other due to electrostatci repulsions, results to complete uncoiling and stretching of the polymer chains

Question 59

what's the diiferent in energy input for emulsion and gel preparations?

Answer 59

smaller energy is used for gel compared to emulsions

Question 60

why smaller input of energy in gel?

Answer 60

because it is thermodynamically stable systems

Question 61

what happend when more energy is used during the gel pre.

Answer 61

leads to disruption if the 3-D network and results in a loss of consistent gel structure