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Hey guys, have you encountered any instances in which you had to calculate creep rate? I am finding some more complex equations that all involve calculus that are above the level usually included in Science Olympiad.

parasaurolophus wrote:Hey guys, have you encountered any instances in which you had to calculate creep rate? I am finding some more complex equations that all involve calculus that are above the level usually included in Science Olympiad.

Yes, several times, though generally using given data points. Plot it to find the linear region (secondary creep), and your standard delta y over delta x usually suffices. I have yet to see a scenario involving calculus.

So I've been doing Materials Science all year, I've got some good notes on the general properties section and on the materials characterization.

However, I'm struggling with the IMFs section.
What is a good textbook to find info about atomic packing and especially miller indices?
Also, anyone know a good source that explains detailed properties about various types of bonds?

Thanks.

Avogadro wrote:

parasaurolophus wrote:Hey guys, have you encountered any instances in which you had to calculate creep rate? I am finding some more complex equations that all involve calculus that are above the level usually included in Science Olympiad.

Yes, several times, though generally using given data points. Plot it to find the linear region (secondary creep), and your standard delta y over delta x usually suffices. I have yet to see a scenario involving calculus.

Thank you so much! So do Materials Scientists generally not care about the primary and tertiary creep? Or rather, for Science Olympiad purposes

Tesel wrote:So I've been doing Materials Science all year, I've got some good notes on the general properties section and on the materials characterization.

However, I'm struggling with the IMFs section.
What is a good textbook to find info about atomic packing and especially miller indices?
Also, anyone know a good source that explains detailed properties about various types of bonds?

Thanks.

Any text used for AP chemistry should have adequate coverage of intermolecular forces generally speaking and, hopefully, some bits on solid state chemistry (even if it's not being tested in ways it once was). After that, I find the chemistry texts inadequate relative to the introductory mat sci ones discussed herein, but they all contribute something.

parasaurolophus wrote:

Avogadro wrote:

parasaurolophus wrote:Hey guys, have you encountered any instances in which you had to calculate creep rate? I am finding some more complex equations that all involve calculus that are above the level usually included in Science Olympiad.

Yes, several times, though generally using given data points. Plot it to find the linear region (secondary creep), and your standard delta y over delta x usually suffices. I have yet to see a scenario involving calculus.

Thank you so much! So do Materials Scientists generally not care about the primary and tertiary creep? Or rather, for Science Olympiad purposes

For Science Olympiad purposes I haven't been too concerned about it. I'm sure it's more important if you're actually an engineer.

Question on closed packed planes coming at you guys if you don't mind. This comes straight off a practice test and is as follows:

Give the Miller indices of a family of close packed planes in copper. Use the conventional notation indicating a family of planes.

The answer is {1,1,1},

1. What is a close packed plane?
2. Where is this plane (isn't it just from 0,0,0 to 1,1,1 the plane that is formed there?)
3. Why is the answer {1,1,1}? How do you just know that?

Ok Thanks for the help.

So I've looked it up and apparently there was something called slip all along, with specific planes that are easier to slip (which I think basically means to break/plastically deform easier on) on and these planes are along the close packed planes. {1,1,1} seemed to be the first one they said. Should I memorize these planes? There really isn't a way to "derive" them, is there? Like you just have to know them?

Hello everyone! I'm hoping to see if anyone can help me figure out how to determine the crystal structure that will be formed or a given material There have been questions on the practice tests that ask us to figure out the crystal structure of materials such as sodium chloride and I am not too sure how to figure that out without memorizing the structures of the materials. Thank you so much for your time!

younessnb wrote:Hello everyone! I'm hoping to see if anyone can help me figure out how to determine the crystal structure that will be formed or a given material There have been questions on the practice tests that ask us to figure out the crystal structure of materials such as sodium chloride and I am not too sure how to figure that out without memorizing the structures of the materials. Thank you so much for your time!

Something that might help would be the wiki, which kind of helps to explain the 6:6 ratio coordination between Na and Cl. Basically it means you have sodium atoms surrounded with 6 other atoms.

I'm really not quite sure though, I think there is something related with the atomic radii, and then you actually take a ratio between them and then you can figure out how it is coordinated... Maybe someone else can help. Hope this helps, though.