Large Hardon Collider

[Eliseos]

That can't be right...

E=mc², so a macroscopic entity has a very high amount of rest energy.

[Khamsin]

That can't be right...

There must be a lot of space between atoms or something. Not to mention the much fewer molecules, proteins, acids, or other advanced structures made up of those 1024 atoms.

[Waef]

E=mc², so a macroscopic entity has a very high amount of rest energy.

It wasn't in regards to the energy, it was in regards to the numbers of atoms. It seems like there would be many, many more atoms than 1024 in a mosquito.

[Eliseos]

Oh oops, yeah that doesn't seem right. ~1000 atoms would be about a micrometer, if an atom's electron cloud on average is 10^-10 meters, or the width of a human hair.

[Kryssan]

See, this is why you post the source too.

[Eliseos]

It's possible they meant the mouth of the mosquito and just didn't write that.

Looks like this http://www.dailytech.com/Scientists+...ticle17598.htm is the source with other blogs copypasta'ing it with a google search.

[Eliseos]

Ok, the original article had 10^24, not 1024. I thought it was something like that since 1023 to 1024 is a weird range to give for something like that.

[Lhyet]

My bad, sorry. I'll be sure to post the source in future~
However, Eliseos had the correct link.

[Jefe]

Going off on a tan, but has anyone stumbled upon high quality bubble chamber photos? Google returns junk. Could use them for a project of mine, thx.

[Woozie]

I did a google image search of the word "bubble chamber, and the first three are pretty much the best qualitiy I've ever seen. They're pretty much the only quality I've ever seen. I don't think they get much better than that (as long as you can see the path of the particles, that's all that matters anyways).

[Kryssan]

Promoting jealousy to all those who would care...


Masters of Fusion


Crossposted:

The presence on French soil of two major fusion projects, ITER and the Laser Mégajoule (LMJ), led France's academic authorities to establish a Master's degree program in Fusion Science in 2006.

The one-year program is offered by ten participating higher education institutions in France, but all students have one thing in common: they spend the third quarter of their course either at Cadarache's INSTN, or in Bordeaux, close to the LMJ installation, and do a six months internship in a fusion lab or installation.

To this day, more than one hundred students have earned the Master's degree in Fusion Science.

This Thursday, 4 February, 23 students gathered in the INSTN amphitheatre near the Château de Cadarache. They were welcomed by Francis Kovacs, Deputy Director of CEA-Cadarache; Pr. Guy Bonnaud, in charge of the Fusion Science Master's program at INSTN; Pr Yves Sarazin, of INSTN-Cadarache, and Jean Jacquinot, former Director of JET and Tore Supra who gave a presentation on "The socio-economic implications of magnetic confinement fusion."

Christophe Guillemaut, 29 - who already holds a Master's degree in physics - and Germain Broydé, 21, are among the three students who have been accepted for an internship at ITER. They will both work on divertor-related matters.

"I remember reading about fusion and the JET installation in a science magazine when I was 12 and being totally enthralled with it," says Christophe. "Later on, while studying physics, fusion appeared to me as the perfect mix of theory and engineering."

Alongside Richard Pitts in the FST Department, Christophe will tackle computer modeling of energy loads on the ITER Divertor.

Broydé, despite his young age, comes to ITER with rich international experience. A third-year student at the Arts et Métiers Engineering School, he has studied in New Zealand and "discovered the nuclear world" at the Indian Institute of Technology in Kampur. His "passion" is energy: he'll be working with Frédéric Escourbiac on thermomechanical analysis of the ITER Divertor.

Of the 23 magnetic fusion students who gathered last Thursday at INSTN-Cadarache, almost half will be doing their internship at Tore Supra. "It will be a great privilege to be working in such environments," Guy Bonnaud told them in his welcoming address.

This isn't so much news as it is promoting angst. Sorry, but I can't resist.

[Eliseos]

Do wish they had something like that in the US. Same for that other nuclear school you posted earlier.

[Kaelan?]

Was looking up stuff on physics simulations on youtube when I ran across this guy:

http://www.youtube.com/watch?v=AicDEJ1mZs0
http://www.youtube.com/watch?v=zpZ4GsukGHM
http://www.youtube.com/watch?v=HtsSOIrmnAY

I'm loving his videos so far, he talks a bit fast but ha been really good at explaining several topics (I wish I knew about him when I was taking fluid mechanics last year). Could have posted in the youtube thread, but I figure the people in this thread would be more interested.

[Kaylia]

He needs to stop moving so much, I had to change window to listen to him.

[Eliseos]

Ok, have a mathy-related homework question and it is pissing me off. I've either forgotten how to do partial differentials, or these are trick questions.

One of the problems is " Let f(x,y) = http://latex.codecogs.com/gif.latex?...}{x^{2}+y^{2}} if (x,y) != 0, f(x,y)=0 otherwise. Prove that a) both http://latex.codecogs.com/gif.latex?...elta%20x})_{y} and http://latex.codecogs.com/gif.latex?...elta%20y})_{x} exist at (0,0) (and find their values) but that b) f(x, y) is discontinuous at (0,0)."

First I use the quotient rule to get:

http://latex.codecogs.com/gif.latex?...elta%20x})_{y} = http://latex.codecogs.com/gif.latex?...2}+y^{2})^{2}}

Then distributing and combining like terms :

http://latex.codecogs.com/gif.latex?...2}+y^{2})^{2}} which looks undefined to me at (0,0), unless if there is some mathy trick I am not seeing. I get something similar for the partial derivative with respect to y, just flip the x and y locations. Pretty much all of the homework problems dealing with partials are not working out for me since they all show undefined at (0,0) when the problem makes it out that they shouldn't be.

Am I going crazy and doing this right, or did I miss something somewhere?

[Kaylia]

I was browsing articles from american journal of physics, and fell on this
http://scitation.aip.org/getabs/serv...ifs=Yes&ref=no
What the...I wish I could open the file at home....it looks so terrible...



I will look at your problem tomorrow Eliseos..sleep pills are kicking in, and I don't see what's wrong with what you did atm. I've done this one last semester, so I'm pretty confident I can still do it...I hope >_>

[Eliseos]

Haha, how does something like that even get published?

Edit: think I figured it out. If I set y=t=x it reduces properly. Is that even legal?

[Enkidu]

I was browsing articles from american journal of physics, and fell on this
http://scitation.aip.org/getabs/serv...ifs=Yes&ref=no
What the...I wish I could open the file at home....it looks so terrible...

Just read it, pretty terrible. It's about... tennis and physics olympics.

I guess that journal is meant to be more interesting/easy to read, rather then just science. You physics people need to publish something though, right?

[Woozie]

I may get to the problem by this weekend, Eliseos. If it's due before next week, then hopefully Kaylia will have time before then. If school isn't canceled tomorrow (which it should be because it's raining glaciers and avalanches outside. It's been snowing non-stop for hours and isn't going to stop until sometime tomorrow) then I definitely wont have any free time before Saturday.

Edit: I'm going to copy and paste the PM I sent you, Eli. So that someone can correct me if I'm wrong or expand on what I said if I'm on the right track.

Posted this in the LHC thread but got no bites on it. If you have time to help me on it, I'd appreciate it, if not no big deal.

Ok, have a mathy-related homework question and it is pissing me off. I've either forgotten how to do partial differentials, or these are trick questions.

One of the problems is " Let f(x,y) = http://latex.codecogs.com/gif.latex?...}{x^{2}+y^{2}} if (x,y) != 0, f(x,y)=0 otherwise. Prove that a) both http://latex.codecogs.com/gif.latex?...elta%20x})_{y} and http://latex.codecogs.com/gif.latex?...elta%20y})_{x} exist at (0,0) (and find their values) but that b) f(x, y) is discontinuous at (0,0)."

First I use the quotient rule to get:

http://latex.codecogs.com/gif.latex?...elta%20x})_{y} = http://latex.codecogs.com/gif.latex?...2}+y^{2})^{2}}

Then distributing and combining like terms :

http://latex.codecogs.com/gif.latex?...2}+y^{2})^{2}} which looks undefined to me at (0,0), unless if there is some mathy trick I am not seeing. I get something similar for the partial derivative with respect to y, just flip the x and y locations. Pretty much all of the homework problems dealing with partials are not working out for me since they all show undefined at (0,0) when the problem makes it out that they shouldn't be.

Am I going crazy and doing this right, or did I miss something somewhere?

I just noticed the LHC thread. I wont have much time to look at it until the weekend, but I do notice that if you apply the actual definition of a derivative, you get 0 as your answer.

So if you have f(x,y) = xy/(x^2 + y^2), then by definition, the derivative at y = 0 is:

limit as h approaches infinity of (f(x,h)-f(x,0))/h. (or use ∆y instead of h, if that's what your professor prefers. Either way you get 0 if I'm doing my math right). I hope that's enough to help. If not, I'll look into it on the weekend when I have more time.

At the particular point (0,0), f(x,y) isn't very well-behaved, so differentiating and putting in numbers isn't a good idea for that particular point of the function.

[Eliseos]

Alright that helped, thanks Woozie. I think I got it (I got x/(h²+x²) which goes to zero as h-> infinity). This is all for my thermo class, I've done double the amount of homework/studying in this class than all my other classes.