Recent content by DukeLuke

I tried separation of variables, but it didn't work because of the coupling. Using z=x+iy I was able to reduce the system to a single equation (multiply the 2nd equation by i and add it to the first). (r^2\nabla^2-1)Z(r,\theta,z) - 2i \frac{\partial Z(r,\theta,z)}{\partial \theta} = 0...

(r^2 \nabla^2 - 1) X(r,\theta,z) + 2 \frac{\partial}{\partial \theta} Y(r,\theta,z) = 0 (r^2 \nabla^2 - 1) Y(r,\theta,z) - 2 \frac{\partial}{\partial \theta} X(r,\theta,z) = 0 any suggestions are greatly appreciated :)

Like you mention national labs have programs that accept students who have just graduated (SULI is one). If you don't end up with a position come spring you can email professors in the grad school you will be going to in the fall. In my program it's not uncommon for students to move early and do...

I think your attitude of accepting responsibility (not blaming others) is excellent and way ahead of a lot of other people in similar situations. It also sounds like there were problems outside of the courses themselves that hurt your studies. To me an important question to answer is to what...

If I apply the Liebniz rule to the term I'm having trouble with, \frac{d}{dr} \int_a^r \frac{x^2}{r^2} f(x) dx = f(r) - 2 \int_a^r \frac{x^2}{r^3} f(x) dx The f(x) cancels with the other integral result of -f(x). If I differentiate one more time using the rule I think I'm left with...

Thanks for the response. I'm confused about how to apply the FTC to the second integral. I'm not sure what \frac{d}{dr} \int_a^r \frac{x^2}{r^2}f(x) dx is because it contains the x^2 and r^2 in the integrand. It seems like some sort of product rule for integration is needed (or...

Any advice on how to approach a problem like this either numerically or analytically? I'm looking to find the form of f where b>a. \frac{1}{f(r)+1} = \int_r^b f(x) dx + \int_a^r \frac{x^2}{r^2}f(x)dx

Thermalne is wrong about Berkeley as they have several groups with large grants working hard on next generation reactors (including pebble bed and breed-and-burn). My advice is to apply to all the top tier schools and visit every single one you get into ( most will pay for your trip :) ). What I...

Getting into good PhD programs is highly dependent on research experience (and good letters of rec from research advisers). Take a look at the CCI program. It's a great opportunity for community college students to work at a national laboratory. An experience like this where you work hard and...

Here is a link to many excellent presentations from last summer's workshop in Erice. There are a few talks on real time dosimetry. http://erice2011.na.infn.it/speakers0.htm

got it, thanks!

Let's say you have four points that define a rectangle in the xy plane centered at the origin (with the x,y axes bisecting the sides). How can you transform these points so that the rectangle lies in an arbitrary plane (defined by a point p and a normal vector n) so it is centered about point p...

Not really lame at all when you have 1000+ papers (and many multidisciplinary). Finding a single paper you know about is not really that difficult with a naming system, but being able to search by keywords or areas would be extremely beneficial for me. I'm going to take a look at some of the...

I have many papers in pdf form and fail at organizing them in a way I can find them efficiently. Any suggestions?

I did physics and math as an undergrad, and I'm currently a graduate student in an engineering department. About 1/3 of the my peers have undergraduate degrees in physics as well. Most of us took a few extra undergraduate classes our first semester, meaning we started slightly behind those who...