For Our Loved Ones in Maryland

Stuff, gunk and whatnot

Sadly, I can not get my pictures to load onto the campus computers, so I will just have to barrage you all with them later. As a note, I actually have been taking more pictures as of late, even if they are all research related.

Speaking of research, it might be interesting to some to know what exactly I am doing this summer. I'll say it first in jargon, which makes more sense to me, and then I will try and clarify what I said. I am studying non-linear acoustics, in particular shocks in a plane wave tube. Dr. Gee has an awful lot of stuff that he wants to look into, but I don't think that I will have time to do much more than just one, which is shock coalescence.

Ok, before I go on, I should clarify that last paragraph. I am studying sound waves that are very loud, which means that we can't make a lot of the approximations and simplifications that are usually done. One example is the small angle approximation is no longer valid. When amplitudes of sound are that large, it turns out that the speed of sound is different for different parts of the waveform. This means that the shape of the wave can change, like this:
When the wave is perfectly vertical in any given position, it is said to have formed a shock. As anyone with some good calculus background could tell you, perfectly vertical slopes are pretty hard to work with in a mathematical sense. And shocks do some pretty funky things in the real world. For example, they eat each other. Usually sound just passes through each other, which means that if two people are talking to you at once, theoretically (I can't do it) you can get what both of them are saying. However, if they were talking with shocks, we have no idea what you would hear right now, especially if there was some nonlinear (very, very loud) noise with it. This eating process is called shock coalescence.

Ok, if you are still reading this, I congratulate you on your perseverance. Finally, I am studying the noise aspect of this shock coalescence. Very smart people have been able to show what happens if you have just one tone at these very loud levels, but people aren't really sure what will happen with random noise (like the noise off of jet aircraft...). Thus, I am building a tube which will allow us to play noise into it at very high levels (today I pumped up to about 155 dB sound pressure level) and see what will happen. However, we want to to this right, so I am spending a lot of time making sure that I build this tube correctly.

Any questions? Please ask them!

Let's see, anything else...? Here's this. While working I have been listening to Pandora, and I heard a song that I hadn't before, which I really like. It is called That's All by Genesis (it's a British rock band that has Phil Colins in it). Look it up, if you don't already know it.

Alaska

Well, I must say that I had a wonderful time in Alaska. The weather was great, the company, too, and I got to see Beluga whales. How awesome is that?

Here are some pictures that I was given of our trip.