Particle Size Analysis Flashcards

Question 1

Q

Challenges

Answer

A

HETEROGENEOUS powder particle size - RANGE
IRREGULAR particle shapes
2D

Question 2

Q

Solutions

Answer

A

Equivalent sphere diameter
Statistics
Analytical techniques

Question 3

Q

Particle shape considers

Answer

A

Convexity, aspect ratio, circularity, solidity

Question 4

Q

Particle size ANALYTICAL TECHNIQUES

Answer

A

Sieving
sedimentation
microscopy
image analysis
laser diffraction
dynamic light scattering
electrozone sensing

Question 5

Q

LASER DIFFRACTION:

particle size range

Answer

A

0.01-3500ym

Question 6

Q

LASER DIFFRACTION:

mechanism

Answer

A

Particles passing through the laser beam scatter light.

ANGLE OF LIGHT SCATTER is measured by photodetectors around sample chamber
- measures LIGHT INTENSITY

Question 7

Q

LASER DIFFRACTION:

smaller particles have a ____ scatter angle

Question 8

Q

LASER DIFFRACTION:

advantages

Answer

A

RAPID (mins)
minimal sample prep
NO CALIBRATION

Question 9

Q

DYNAMIC LIGHT SCATTERING:

particle size range

Answer

A

0.3nm-10ym

Question 10

Q

DYNAMIC LIGHT SCATTERING:

mechanism

Answer

A

(same as laser diffraction)
BUT
Photodetectors measure FLUCTUATIONS in scatter.

Scatter due to BROWNIAN MOTION

Question 11

Q

Compare LD & DL:

Answer

A

LD uses wet & dry samples (DL: wet only)
LD: broader particle size range
LD measures ANGLE OF LIGHT SCATTER
DL measures FLUCTUATIONS of light scatter

Question 12

Q

NORMAL DISTRIBUTION CURVE:
mean
median
mode

Answer

A

mean=median=mode

Question 13

Q

NORMAL DISTRIBUTION CURVE:

shows

Answer

A

UNIFORMITY of particle size

Question 14

Q

BIMODAL DISTRIBUTION:

relate modes & peaks

Answer

A

1 peak = 1 mode

2 peaks = 2 modes

Question 15

Q

BIMODAL DISTRIBUTION:

shows

Answer

A

2 or more distinct populations in powder

Question 16

Q

NEGATIVE SKEW:
mean
median
mode

Question 17

Q

NEGATIVE SKEW:

shows

Answer

A

MORE LARGER PARTICLES

Question 18

Q

NEGATIVE SKEW:

peak lies on ___ side

Question 19

Q

POSITIVE SKEW:
mean
median
mode

Answer

A

mean>median>mode

Question 20

Q

POSITIVE SKEW:

shows

Answer

A

MORE SMALLER particles

Question 21

Q

POSITIVE SKEW:

peak lies to ____ side

Answer

A

LEFT

closest to y axis

Question 22

Q

D values:

calculate

Question 23

Q

SPAN

equation

Answer

A

(D90-D10)/D50

Question 24

Q

SPAN shows

Answer

A

width of particle size distribution

Question 25

Q

IQCS<0

Answer

A

NEGATIVE SKEW

Question 26

Q

IQCS>0

Answer

A

POSITIVE SKEW

Question 27

Q

IQCS=0

Answer

A

NORMAL DISTRIBUTION

Question 28

Q

IQCS values lie between range …….

Answer

A

-1 and +!

Question 29

Q

IQCS shows

Answer

A

Interquartile coefficient of skewness

Question 30

Q

POLYDISPERSITY INDEX: shows

Answer

A

uniformity of particle size

Question 31

Q

POLYDISPERSITY INDEX:

assumes

Answer

A

NORMAL DISTRIBUTION

Question 32

Q

POLYDISPERSITY INDEX:

equation

Answer

A

SD

mean particle size

Question 33

Q

POLYDISPERSITY INDEX:

MONODISPERSE

Answer

A

narrow dist, uniform particle size

Question 34

Q

POLYDISPERSITY INDEX:

POLYDISPERSE

Answer

A

broad dist

variable particle size

Question 35

Q

DYNAMIC LIGHT SCATTERING:

which equation relates?

Answer

A

Stokes-Einstein Equation