APSS

Question 1

what kind of equipment separates aerosols using the inertia of a particle

Answer 1

impactor

Question 2

what kind of equipment can you use to obtain mass distribution?

Answer 2

cascade impactor

Question 3

which dimensionless number relates to inertia and relaxation time?

Answer 3

stokes number

Question 4

for the design of impactor, what must be the reynolds number and H/D_j ratio

Answer 4

500 - 3000 and H/D_j is greater than 1.5

Question 5

a mobility particle size spectrometer is composed of?

Answer 5

bipolar diffusion charger, DMA, CPC

Question 6

what are the types of Mobility Particle Spectrometer?

Answer 6

differential and continuous

Question 7

how should we design DMA?

Answer 7

we should use long DMA for large Dp and short DMA for small Dp

Question 8

why do we use pre-impactor

Answer 8

to eliminate the influence of multiple charged particles greater than the nominal size

Question 9

when should we not use a pre-impactor?

Answer 9

if the MPSS size range is up to 800 nm

Question 10

how can we calculate the internal losses due to diffusion of an MPSS?

Answer 10

method of equivalent pipe length

Question 11

what particles we use for size calibration of MPSS?

Answer 11

latex particles

Question 12

how do we check the comparabilit of candidate MPSS and reference MPSS?

Answer 12

we check the agreement of their measurements by comparing their linearity and RSQ

Question 13

what does a shift in the graph of MPSS mean in calibration?

Answer 13

sheath air might be incorrect

Question 14

what are the elements we can use for bipolar charging?

Answer 14

krypton, nickel, Americium

Question 15

stokes number is the ratio of what?

Answer 15

particle stopping distance and nozzle diameter

Question 16

which geometry leads to higher stokes number, rectangular or round nozzle?

Answer 16

rectangular

Question 17

what are the different types of particle size spectrometer we use?

Answer 17

electrical mobility and aerodynamic mobility or time of flight

Question 18

which instrument measures the time-of-flight between two laser beams?

Answer 18

laser anemometer

Question 19

what is the time difference between two pulse maxima

Answer 19

time-of-flight

Question 20

what is particle coincidence in aerodynamic PSS?

Answer 20

when two or more particles are in the measuring volume at the same time

Question 21

what is the aerodynamic particle size range of APSS?

Answer 21

0.5 to 20 microns

Question 22

what is the operating pressure of an APSS?

Answer 22

0.4 to 1 bar

Question 23

what should be the ambient conditions for APSS?

Answer 23

10 - 40 degC and less than 40% RH