Archive for July, 2011

Let’s make some noise!

Today for Physics Friday, let’s make some noise! Specifically, let’s talk about signals and noise, what they are, and why we care about them.

Most of the time, we are primarily interested in signal. I would broadly define a signal as any source of information that is of interest to the observer. For instance, a satellite can beam a signal down to your television that you can watch. A doctor listens to your heartbeat through a stethoscope. An antenna collects radio waves and sends the resulting music through your car speakers.

However, I’m sure we are have faced situations where, for example, we weren’t able to actually hear the song playing on the radio because of the static being broadcast through our speakers as well. That static is an example of noise….not just because it’s noisy in an audible sense, although the ideas are definitely related. Noise is any source of information that is not related to the desired signal yet competes with it for attention. In that case, you might consider yourself to be the signal and your little brother to be the noise.

In a more technical sense, a signal is usually an electronic pulse defined by a changing voltage as it travels through wires of a circuit or other electronic devices. If you remember back to our discussion of frequency and sine waves, then you can envision most electronic signals as having voltages that vary in time like the sine wave. There are other shapes of electronic signals, but we’ll stick to this one in our analysis here. Noise on a sine wave is considered any fluctuation in the amplitude or zero crossing (time, or phase) from the expected value.

Often, you will hear people discussing the signal-to-noise ratio (or SNR). This parameter describes exactly what it says: in compares the amount of signal you have to the amount of noise you have. For audible signals, you would compare the loudness of the signal compared to the loudness of noise. For a light signal, you might compare the brightness or intensity. For an electronic signal, you would compare the voltages  (which, if you were curious, is related to the power by Ohm’s Law: P=V^2*R, where R is the resistance in your circuit). As with any fraction, if your signal on top is really big and your noise on bottom is really small, then the signal-to-noise ratio is big, which is generally desired. However, if noise begins to get too big on the bottom of the fraction, the overall fraction goes down. This would result in the aforementioned dilemma of not being able to see the signal as well: i.e., not hearing the song on the radio due to static.

Simplistically, we would just continue to crank up the signal to increase the SNR. However, most systems that generate signals are complex, and putting more energy into the system to crank up the signal will inevitably cause more sources of noise to appear and get larger as well. Therefore, this isn’t always an option.

Day to day for you and me, we get plenty of signal and are able to drown out the noise. But in scientific applications that require lots of precision, noise can be a big problem. For clocks, this means that you and I will know what time it is well enough to get to work on time, but for something like GPS that needs many decimal places of clock accuracy or for a signal that is very faint, noise can start to be a problem. It’s very easy to compete for attention at seventeen decimal places! It’s like trying to go to sleep with someone mowing the lawn right outside your window…something you would barely notice or hear when awake and surrounded by normal noises during the daytime. When the overall signal goes down, the noise is much more pronounced.

In my research, my bread and butter is analyzing the noise that gets in the way of our signals. Not only do I try to locate the sources of noise, I also characterize what kind of noise it is and, ultimately, try to get rid of it! Indeed, my overall thesis topic is that of generating low noise signals from optical (laser) sources.

A colleague of mine who is older and has had an illustrious career in astronomy and physics is fond of saying that, as a youth, he only cared about signals (that is an astronomer’s bread and butter!). However, as he got older, he began to find that the noise that he ignored became more and more interesting and important to him. Now he looks at noise almost exclusively. He told me I was very mature and wise beyond my years to get interested in noise now while I am young. 😉 Granted, I did just fall into this area of research without much forethought, but it indeed has been interesting with benefits to all areas of science. My friends in other areas of physics occasionally ask me about it, and I get queries from all over the world at conferences or in response to journal papers about my work.

In some ways, looking at noise is kind of like being the exterminator of the science world, getting rid of all the pests that get in the way of someone’s main agenda. But as technology pushes toward fundamental limits, noise becomes a very important issue. Fortunately for science, I’m here with the noise flyswatter!

Before this analogy gets any sillier, I’ll just abruptly wrap up this edition of Physics Friday. Stay tuned in coming weeks for more science topics you never thought you’d want to know!

 

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Would you like fries with that?

In stark contrast to fresh squash, ripe tomatoes, and verdant garden greens stands the newest addition to the New York State Fair menu: The Big Kahuna Donut Burger.

You heard that right. It’s a quarter pound burger with all the fixings piled onto a sliced grilled donut. Now, don’t get me wrong, I love a good hamburger, and a fresh glazed donut can occasionally hit the spot, but I imagine that I would prefer them separated. Of course, never knock it till you try it, right?

To be fair, you can get it with lettuce, onion, and tomato, which are vegetables and downright good for you, right? However, it will set you back 1500 calories, making it the size of two normal meals for a day. Of course, it is a donut and a hamburger, so it really does span two daily meals. Just remember to eat  a “sensible dinner,” okay?

Squashzilla

While we were gone for a week, I often wondered how our garden was doing. Was it getting plenty of water? Were any veggies growing? Did anything die? When we got back, we found our garden was a little wild but doing pretty well.

Our tomato plants are going a little crazy, which is great! This is the first year we’ve had any luck at all with tomatoes. They are kind of crowding our bell peppers, but they don’t seem to mind; there are half a dozen little peppers coming along (which is also the best luck we’ve ever had with peppers, too).

The most amazing sight to behold, however, was the gigantic squash we had. When we left, I couldn’t remember seeing a squash any bigger than my pinkie finger. But in ten days’ time one had developed to be a monster. We harvested it, along with a smaller one (what I would usually consider normal!) and set them out for comparison (even with vegetables, I can’t quit measuring!).

Squashzilla is nearly one foot long! The other squash is the same size you’d get in the grocery store, or even slightly larger. For reference, here’s how squashzilla compares with my dachshund, Murphy, as a reference.

Squashzilla appears to be not much smaller than the main body of our pup! That’s quite an amazing squash. It’s also amazing that I got a picture of Murphy sitting calmly beside the squash instead of sniffing and investigating.

Now, I just have to decide what to do with these squash and the many more that will inevitably follow. I will usually either bake or grill them, which is simple and very yummy. I often saute cubed squash with other veggies for use in main dishes. Feel free to share your favorite squash recipes, though, because I envision having more than I can possibly deal with in the near future!

If at first you don’t succeed

….then what’s to say you’ll manage to do it right next time, either? Oh, wait. I think I got that saying wrong.

I went into the machine shop to drill some holes into a mounting plate today; however, I didn’t have a lot of luck. Anyone who has tried to make four holes in one object perfectly match four holes in another object will understand how being just a millimeter off can ruin everything. I certainly didn’t nail it the first time with my drilling, so I gave up and went to eat lunch.

I guess it’s probably time to dust the aluminum bits off and make a second attempt. This time I probably need to recruit a volunteer to help me with the drill press. I wasn’t able to lift the heavy platform earlier, which would have been helpful. My alternative approaches obviously didn’t work, so I’ll probably have better luck if I take care of it this time instead of working around it. Here’s to try, try, trying again until it’s done.

A fresh start

Hey everyone! I am back after my one week hiatus. As I’ve mentioned plenty of times before, it’s hard to get back into the swing of things after a break of some kind, and this Monday is no different. It’s particularly more challenging today because I am quite tired.

However, I feel like now is a very good time for a fresh start. It’s a little bit past half-way through the year, and all my major summer plans have been accomplished. Coming home and back to work after last week’s absence feels like an opportunity for a new beginning. I felt really motivated yesterday thinking about it, but today I am so exhausted from traveling that it’s hard to recover that enthusiasm and start running out of the gate. However, even when I don’t feel like doing something, I hope that I can still pick myself up and at least stumble along a little bit. A start of some kind is better than not starting at all. 🙂

At home and at work, I have a list of things that I need and want to get done in the near future. However, while I do have some longer-term goals, I will as usual focus on just a few tasks for this week to get the ball rolling. At work this week I want to move my photodiode set-up to its final location and begin arranging our equipment for our upcoming measurement with our guest researcher (just a mere three weeks away now!). I also need to proofread a paper that our group will soon submit to a journal.

At home, my biggest goal is getting organized with meals again. In a way, it’s hard to come back to an empty refrigerator after a week; on the other hand, I am excited for a fresh start here as well. Without a bunch of food needing to be used up, I can actually start planning meals now before I go to the grocery store and get exactly what I need for the upcoming week. Secondly, the lawn needs work after being neglected for a week. DH will probably mow, and I will take charge of weeding and pruning old flowers and foliage that have come and gone. Finally, I plan on finishing unpacking this evening.

Without further ado, I shall wrap up here and go make that aforementioned strong start back to work in the lab. Wish me luck!

One hundred posts

This is my one hundredth post on this blog! I’ve been steadily blogging for five months (and sporadically since the beginning of the year) to talk about my research and other stuff going on in life in general. Hopefully you haven’t been bored silly or anything, although I do realize some topics are much more interesting than others. That’s a pretty accurate description of a scientist’s research as well!

At the beginning of the year, I gave a lot of though to doing a blog-a-day as a challenge for the new year. I had a little trouble coming up with topic that would be somewhat meaningful and would be different than just an online journal within which I complained about stuff I didn’t like. Once I was inspired to expound upon my experiences in my final stretch of graduate school, I eventually settled into the current format. I never realized quite how involved blogging would be. I try to come up with meaningful topics of discussion every day, and I also try to spend enough time making quality content. I know I don’t always succeed and sometimes I have short or rambling posts, but hopefully the majority of the blog is well-written, entertaining, and informative over a wide range of topics.

Even if my blog isn’t widely popular or relevant to a large group of people, it has been a nice experience to at least keep track of my progress for myself. It’s also a good motivator and often keeps me accountable to 1. make sure the blog post is done for each day, and 2. follow through with the tasks I’ve told the world I intend to do!

Most of all, I’d really like to thank you for reading my blog! It’s always a nice feeling to know people are interested in my perspective on things, and, as I said, I do try to make it a quality and interesting read for you (and if you don’t think that SI units and Pi Day are enthralling subjects, then you’re just a poo-poo head ;)).

After all this intense blogging, I’ve decided I will most likely be taking a break for the next week, but I’ll be back to my regularly scheduled ranting and raving very soon! Thanks again for hanging out with me here so far. 🙂

My garlic crop!

As promised, this week I harvested my garlic crop! It was very exciting to see what they were actually doing under the surface; their progress has been a big secret since last October when I planted the cloves. Here are my seven bulbs!

You see that one little bulb is quite clean while the others are dirty. I harvested that one last Saturday to check the status of the crop as a whole, and it got caught out in the rain. The other six were just harvested Wednesday evening. The garlic is supposed to stay dirty (not washed off with water) and attached to the stalk for a few weeks while they dry out. The clean one will probably be fine, though.

The really long stalk with the bulbous end is the scape. It’s evidently something like a flower without actually being, you know, a flower. The whole scape is supposed to be edible and is evidently very flavorful to sautee, although I haven’t tried it. Garlic growers are pretty much evenly divided about leaving the scape on or removing it from the garlic. Some claim that if you leave it, the plant puts energy into the scape that it could be using to develop the bulb even more. This time I just decided to let the scape be. Maybe next year I will experiment with cutting it off earlier.

My previous attempts at garlic have all mostly failed; last year, while I did actually get a couple of bulbs, they were tiny due to the compacted soil in which I planted them. This time I really loosened up and amended the soil before planting, and it evidently helped. These bulbs aren’t huge, but they are definitely more robust and lovely than what I’ve grown before!

I’m very excited about my crop. I guess garlic is just one of those things I never heard of someone growing in a garden, so the idea of having it next to my tomatoes and squash is a little bit exotic. I’m very pleased with the results, and maybe next year I’ll have an even bigger crop!