Linear Density, Planar Density, Atomic Packing Factor {Texas A&M: Intro to Materials (MSEN 201)}

Tutorial illustrating how to calculate linear densities, planar densities & atomic packing factors in an example (FCC) lattice.
Video lecture for Introduction to Materials Science & Engineering (MSEN 201/MEEN 222), Texas A&M University, College Station, TX.
engineering.tam...

[@j.s.s9108]

for the linear density ,can we say that the line pass through an 1/2(1/8) atom ? cuz the corner atoms are shared by 1/8th of their volumes ? why did we just consider it as half a full atom in the first example

[@yesyouareright7076]

J.S.S same doubt

[@nimes664]

Yeh,same doubt

[@francescobandozzi7708]

Same doubt for me

[@ay-pn8jy]

@@francescobandozzi7708 same 🤣

[@yazeedalmakahlah9564]

well, after 6 years, No .
Because you are considering your density along line, so ask yourself how it is shared along a line ? Not by volume.

[@MumenRider78]

Why are the number of atoms for those small corner bits a half, in the linear density and a quarter for the planar density?

[@pjshamberger]

Miah We only count that fraction of atoms within the line/area/volume of interest. So if we take planar density, the question is "how many atoms are there per unit area?" where the area is a square. if an atom is sitting exactly on the edge of a square, half of that atom is in one square region, the other half is in the neighboring region. Similarly, if the atom is sitting exactly on the corner of a square, it's evenly split between the for squares touching at that corner. This is the only way to make sure that the planar density is independent of where the square is located (picture shifting that square a little to the left or the right). Try this with a simple square lattice, and hopefully it should make a bit more sense!

[@AkashDave11]

your videos are well explained thanks

[@ilaydanur8426]

this video the best explained than others thanks

[@arjundas3314]

This video is confusing,why we took half in calculating linear density and why we took 1/6 while calculating fcc planar density ? Not explained properly. And the voice is also low. We need a headphone to listen.

[@anouaryousfi6087]

the voice is low , otherwise great video (y)

[@damny0utoobe]

Great vide this explained FCC for me

[@blank_ec828]

why is that 1/6? in (111)

[@aysen6217]

1 1 1 triangle sides will be equal to each other. so 60 degress for each angle. 60 is 1/6 part of 360

[@0899103532]

what planar density highest in fcc?

[@Mnzmanzmz]

Thank you💕💕

[@SouravKumar-fy8ff]

Excellent, thanks from india

[@emir650]

Thanks so much

[@Robmex10]

I understand that {111} and {111} w/ all negatives have the same outcome, but its extremely misleading, and doesn't follow the axis assumed,

[@IvanOooooooze]

Sweeeeet! Thanks!

[@emreo.9196]

perfect content ty so much

[@hafidzazharjakaria2615]

very well explained

[@joshuaval4590]

Wow .... Gracia's really learnt a lot

[@vicky-leehenning7536]

How do you calculate whether it is a fcc or bcc crystal structure

[@sfindaa8523]

I think it's less confusing in the Linear density to say # of radii rather than # of atoms. Because it's definitely one quarter of an atom on each edge for the LD

[@zzztttsss]

i think you mean 1/8 of an atom at the corners. and the # of radii is the # of atoms. if you pass a vector through one radius of an atom, then the vector passed through one half of that atom. if you pass a vector through two radii of an atom, then the vector passed through that entire atom.

[@bishalghimire1211]

This video creates more confusion