Author Topic: n-word Posts  (Read 6874 times)

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Ken B

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Re: n-word Posts
« Reply #60 on: July 24, 2014, 02:29:08 PM »
Just say no to fluid mechanics.

bwv 1080

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Re: n-word Posts
« Reply #61 on: July 24, 2014, 07:09:44 PM »
or, to go completely friccin nuts, you can combine Navier-Stokes w General Relativity

http://personalpages.to.infn.it/~alberico/QGP2008/Romatschke/Romatschke-lectures.pdf

Offline k a rl h e nn i ng

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Re: n-word Posts
« Reply #62 on: July 25, 2014, 03:18:53 AM »
I might. Then again, I might not.
Karl Henning, Ph.D.
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bwv 1080

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Re: n-word Posts
« Reply #63 on: July 25, 2014, 06:24:05 AM »
Here is QFT and NS.  Checking their derivation I think they got a sign wrong on page 15

http://arxiv.org/pdf/1305.0798v2.pdf

"We study linear and nonlinear wave propagation in a dense and cold hadron gas and also in
a cold quark gluon plasma, taking viscosity into account and using the Navier-Stokes equation.
The equation of state of the hadronic phase is derived from the nonlinear Walecka model in the
mean field approximation. The quark gluon plasma phase is described by the MIT equation of
state. We show that in a hadron gas viscosity strongly damps wave propagation and also hinders
shock wave formation. This marked difference between the two phases may have phenomenological
consequences and lead to new QGP signatures"

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Re: n-word Posts
« Reply #64 on: July 25, 2014, 07:06:36 AM »
Here is QFT and NS.  Checking their derivation I think they got a sign wrong on page 15
*universe implodes*

Yeah, sure, I totally see what you mean... :-X
Beethoven's Op. 133 -- A fugue so bad that even Beethoven himself called it "Grosse".

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Re: n-word Posts
« Reply #65 on: August 24, 2014, 01:56:31 AM »
Classes start this coming Tuesday (day after tomorrow!) and I still haven't gotten my departmental TA assignment... Fingers crossed for machine design (kinematics and kinetics). I'll probably get it. It was my first choice (after that were fluids and thermo) and no one else probably wants it. I love that kind of stuff. Graphical and analytical four-bar linkage synthesis, kinematic linkage analysis, cams, and gears. One of my all-time favorite classes in mechanical engineering. It's a good thing I liked it, though, because the homework in that class took forever. The one on acceleration took me 20 pages of engineering paper and a few days to figure out and complete. Once you figure it out it isn't really difficult -- just tedious.

Stuff like this:
Beethoven's Op. 133 -- A fugue so bad that even Beethoven himself called it "Grosse".

Ken B

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Re: n-word Posts
« Reply #66 on: August 24, 2014, 05:47:05 AM »
Classes start this coming Tuesday (day after tomorrow!) and I still haven't gotten my departmental TA assignment... Fingers crossed for machine design (kinematics and kinetics). I'll probably get it. It was my first choice (after that were fluids and thermo) and no one else probably wants it. I love that kind of stuff. Graphical and analytical four-bar linkage synthesis, kinematic linkage analysis, cams, and gears. One of my all-time favorite classes in mechanical engineering. It's a good thing I liked it, though, because the homework in that class took forever. The one on acceleration took me 20 pages of engineering paper and a few days to figure out and complete. Once you figure it out it isn't really difficult -- just tedious.

Stuff like this:

You can't fool me. That's actually part of the score of Gruppen.

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Re: n-word Posts
« Reply #67 on: August 25, 2014, 06:26:28 AM »
You can't fool me. That's actually part of the score of Gruppen.
:laugh:

I just found out that I got it, so I'm happy. This can be the theme for this year's class. I've always thought that it sounded very mechanical.
           


There's also the opening of Bartok's Sonata Sz. 80 (solo piano). And, of course, Honegger's Pacific 2.3.1.
Beethoven's Op. 133 -- A fugue so bad that even Beethoven himself called it "Grosse".

Ken B

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Re: n-word Posts
« Reply #68 on: August 25, 2014, 06:09:13 PM »
:laugh:

I just found out that I got it, so I'm happy. This can be the theme for this year's class. I've always thought that it sounded very mechanical.
           


There's also the opening of Bartok's Sonata Sz. 80 (solo piano). And, of course, Honegger's Pacific 2.3.1.
You may know it but I saw a Brit TV thing once about a guy who recreated and repairded and elaborated centuries old automata. Geears, cam, etc, to drive not just cuckoo clocks etc but robots and figurines that were simply amazing. Wish I had more details.

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Re: n-word Posts
« Reply #69 on: August 28, 2014, 10:37:27 AM »
Just say no to fluid mechanics.
I'm about to leave to go to my fluid mechanics class. I think we're covering tensors today, but I could be wrong and it might be sometime next week. I'll let you know :D.
Beethoven's Op. 133 -- A fugue so bad that even Beethoven himself called it "Grosse".

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Re: n-word Posts
« Reply #70 on: August 28, 2014, 10:41:43 AM »
Good Signior Leonato, you are come to meet your trouble:  the fashion of the world is to avoid cost, and you encounter it.
Karl Henning, Ph.D.
Composer & Clarinetist
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http://www.karlhenning.com/
[Matisse] was interested neither in fending off opposition,
nor in competing for the favor of wayward friends.
His only competition was with himself. — Françoise Gilot

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Re: n-word Posts
« Reply #71 on: September 16, 2014, 06:17:38 AM »
I'm about to leave to go to my fluid mechanics class. I think we're covering tensors today, but I could be wrong and it might be sometime next week. I'll let you know :D.
For Ken ;) (meant to post this last week). Now I can say (in response to the question you asked a few months ago) YES! I have covered tensors, though I am not totally convinced yet as to why I'd prefer them over vectors. I'm sure that will change as we start deriving equations using them, though.
Beethoven's Op. 133 -- A fugue so bad that even Beethoven himself called it "Grosse".

Ken B

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Re: n-word Posts
« Reply #72 on: September 16, 2014, 06:41:39 AM »
For Ken ;) (meant to post this last week). Now I can say (in response to the question you asked a few months ago) YES! I have covered tensors, though I am not totally convinced yet as to why I'd prefer them over vectors. I'm sure that will change as we start deriving equations using them, though.

It's not a matter of preferring alas. Tensors are a generalization of vectors. There are places where a vector description of something gets awkward.  I wish I had an easy way to explain the essence of what makes a tensor different from a vector, but I am not sure I can.
It is actually symmetrical but it might help to think of contravariant tensors as things to be measured, and covariant ones as things that do the measuring. I recommended a book, I think geometrical vectors by weinberg. I'll see if I can recall it exactly.
if, unlike me, you are not anal about formal definitions and mathematical rigor then the best book is the start of Gravitation by Misner et al. Very visual.

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Re: n-word Posts
« Reply #73 on: September 16, 2014, 09:47:24 AM »
It's not a matter of preferring alas. Tensors are a generalization of vectors. There are places where a vector description of something gets awkward.  I wish I had an easy way to explain the essence of what makes a tensor different from a vector, but I am not sure I can.
It is actually symmetrical but it might help to think of contravariant tensors as things to be measured, and covariant ones as things that do the measuring. I recommended a book, I think geometrical vectors by weinberg. I'll see if I can recall it exactly.
if, unlike me, you are not anal about formal definitions and mathematical rigor then the best book is the start of Gravitation by Misner et al. Very visual.
No, I understand that -- a scalar is a zeroth-order tensor, a vector is a first-order tensor, etc. I took the undergraduate fluids with the same professor and we derived equations using vectors. I have never dealt with tensors, but he made it sound like the derivations can go much further with tensors than they can with vectors.

Also, by preferring, I was referring to index notation versus the standard vector ('e'-hat) notation that I'm used to for dealing with first-order tensors. The problems on our first homework dealt with vectors, but we had to use index notation to get used to it.

YES!!! The library has the Misner. I couldn't find anything by Weinberg, but right now what I need is a good visual approach especially since this is for a concrete subject like fluid mechanics. I was going to stop by the library to get a book/bio on Webern and another on Messiaen (not joking!), so I'll get this one as well. Thanks -- any textbook suggestions you have are of great use to me! It's time consuming to go to the library or go on Amazon and just use trial-and-error to find a good book when I need help on something.
Beethoven's Op. 133 -- A fugue so bad that even Beethoven himself called it "Grosse".

Ken B

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Re: n-word Posts
« Reply #74 on: September 16, 2014, 10:22:58 AM »
No, I understand that -- a scalar is a zeroth-order tensor, a vector is a first-order tensor, etc. I took the undergraduate fluids with the same professor and we derived equations using vectors. I have never dealt with tensors, but he made it sound like the derivations can go much further with tensors than they can with vectors.

Also, by preferring, I was referring to index notation versus the standard vector ('e'-hat) notation that I'm used to for dealing with first-order tensors. The problems on our first homework dealt with vectors, but we had to use index notation to get used to it.

YES!!! The library has the Misner. I couldn't find anything by Weinberg, but right now what I need is a good visual approach especially since this is for a concrete subject like fluid mechanics. I was going to stop by the library to get a book/bio on Webern and another on Messiaen (not joking!), so I'll get this one as well. Thanks -- any textbook suggestions you have are of great use to me! It's time consuming to go to the library or go on Amazon and just use trial-and-error to find a good book when I need help on something.
I muffed the name as I feared
http://www.amazon.com/Geometrical-Vectors-Chicago-Lectures-Physics/dp/0226890481/ref=sr_1_4?s=books&ie=UTF8&qid=undefined&sr=1-4&keywords=geometric+vectors+tensors
It's quite useful.
But if you can lug Misner Thorne Wheeler around it's very useful on visualizing. And it's a babe magnet.  ;)

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Re: n-word Posts
« Reply #75 on: September 16, 2014, 04:25:36 PM »
I muffed the name as I feared
http://www.amazon.com/Geometrical-Vectors-Chicago-Lectures-Physics/dp/0226890481/ref=sr_1_4?s=books&ie=UTF8&qid=undefined&sr=1-4&keywords=geometric+vectors+tensors
It's quite useful.
But if you can lug Misner Thorne Wheeler around it's very useful on visualizing. And it's a babe magnet.  ;)
I wasn't expecting the book to be that big, but I guess that gravitation is a pretty complex subject. I flipped through it so far and the physics looks utterly terrifying, but the math I can certainly handle. I'm sure that it will be useful. I'll see if I can find the 2nd one as well.
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Re: n-word Posts
« Reply #76 on: September 17, 2014, 02:57:01 AM »
"nebulous"
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Re: n-word Posts
« Reply #77 on: September 29, 2014, 03:08:43 PM »
I have an exam tomorrow in my engineering math course. I took the class last year and did well, so it shouldn't be bad.

Guess what it's on?

Eigenvalues and Eigenvectors!

...actually, it isn't about finding them, instead covering related things like diagonalization, quadratic forms, solutions by eigenvector expansion, etc. I always panic during exams when finding eigenvectors because I think "Oh no! The rows are linearly dependent! I must have done something wrong!" Then I realize that they are supposed to be linearly dependent, solve in terms of a parameter, set the parameter equal to 1 (that's just how I do it), and feel better. I first learned about eigenthings almost five years ago, but I still panic (though wrongly). Then there is always the case where there is a repeated eigenvalue and I have to worry about getting two eigenvectors from one eigenvalue. I am very comfortable with the concept, though.
Beethoven's Op. 133 -- A fugue so bad that even Beethoven himself called it "Grosse".

kishnevi

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Re: n-word Posts
« Reply #78 on: September 29, 2014, 05:25:46 PM »
Attack of the Eigenthings

that would have made a great 1950s sci fi movie, I think.


Well, Nate, may the Eigenforce be with you.

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Re: n-word Posts
« Reply #79 on: September 30, 2014, 12:15:20 AM »
Attack of the Eigenthings

that would have made a great 1950s sci fi movie, I think.


Well, Nate, may the Eigenforce be with you.
:laugh: :laugh:  :laugh: Thanks! :)

Our professor calls it eigenhunting. You could fill a dictionary with the number of words accepted by mathematicians that have "eigen" as a prefix. Off of the top of my head -- eigenvalue, eigenvector, eigenspace, eigencondition, eigenproblem, eigenfunction, eigenface (yes, that is really one related to image processing), eigensolution, eigendecomposition, eigenmode, eigenstate, eigenpair, eigenbasis ... eigenetc...

It's a problem that has fascinated me in math since I first learned it. Since I have a bit of a backwards education when it comes to math, I first learned the eigenvalue problem in the context of solving systems of linear ODEs. I didn't think much of it until we started learning phase plane analysis of systems. Then I was intrigued. Why does a system evolve along the direction of its eigenvectors in the phase plane? What is the meaning of this? Then, when I took a class on nonlinear dynamics (still no linear algebra yet!) it made more sense. Then I took classes in linear algebra, system dynamics and controls, and even vector spaces (the latter was way over my head as a non-math major). It all made sense (I'm a very slow learner, so it took many classes for me to "get it"). I must have seen the stuff in 10 different courses by now and it still fascinates me.

What's more is we covered the Sturm-Liouville problem last year (we'll do it again this year since I'm re-taking the class for various reasons). Now we have function spaces? Until then, I had only heard of them!

It's all based off of such a simple problem that could be explained in words to someone even with no mathematical background. Even with the math, the basic problem is a simple computation that a high school student could do (though, they probably wouldn't know that they could). But, it leads to so many things that are just -- well -- beautiful.



An interesting (though not-mathematically-rigorous) visual example:


EDIT: I think it went well. Last year I got an 87/100 which wasn't bad considering the class average was a 57/100. I was irritated with myself for not knowing a proof that the professor specified in the syllabus. I'm hoping for above a 95 this year (my standards are not usually this high, but since it isn't unreasonable since I've taken the class before). I forgot this one thing about quadratic form, but it was very minor. I might have still done it correctly.
« Last Edit: September 30, 2014, 04:40:03 PM by EigenUser »
Beethoven's Op. 133 -- A fugue so bad that even Beethoven himself called it "Grosse".