I think I am done with my experiments. Whew. This summer I was able to run the test loop that my colleagues and I devised to investigate boiling flow in expanding microchannels. A mouthful, eh? True, but the data output is a rather a bigger bite. It's no Large Hadron Collider, but my four experiments ran to a 100 MB chunk of text data. What do you do with this? Well, certainly you write programs (in MATLAB) to organize it, do calculations, sniff through it, plot the parts you want, and so on. But you look at all of it. And you don't delete. And you don't fudge. This is not to say that you don't analyze it, or ignore the big spike where you turned power on, or even perhaps use a smoothing routine on the thermocouples (which are as noisy as undergrads), but if you do any of these things you say so. You work only from what the data confidently allows you to say, and the more layers of analysis lie between you and the data, the bigger the uncertainty becomes. You don't clip... read more
I am a researcher. That is why I am pursuing a PhD, that is why I obtained a Master's, and that (at some level) is what I want my career to be when I am finished with grad school (where I tutor on the side). Research is a business of trust. If I publish, I am asserting that this work represents the truth as far as I can carefully deduce. Others who may use my work rely on that assertion; why would you use, say, a heat transfer model prepared by a kook or a liar? Peer review is meant to guard the gates of academic literature from error, which is a tried and true, if not foolproof, method. But what about undergraduates? They are not researchers. They are not publishing. They are, by and large, turning the crank on basic problems. So what if they share work, or hire an unscrupulous tutor? It's a victimless crime, right? Let's pause and think out that line of thought. If I am a recruiter at General Electric, and a resume comes across my desk with a fabulous GPA from a school... read more
Engineering and science are slow fields. Yes, you read about breakthroughs, revolutions, and the like, but those headlines are the fruit of years of labor. I acknowledge that all fields require planning, thought, and care, but the businessman can just go out and make a deal (perhaps a bad one) in a fairly short amount of time. You can't just go out and build a bridge (however poor) in an afternoon, or even a week. Enough anecdotes. If you want to pursue an education, especially in the science/engineering fields, you must commit yourself to it for substantial periods of time. This is not easy. It is done at the expense of fun, friends, and even perhaps family. As a PhD student, I do not get to spend nearly as much time with my wife as I did when I was a practicing engineer. It is a very rare weekend when I can hang out with friends. A good education makes demands on you. All this to say, if you are serious about learning, you will learn. If you are unwilling to give... read more
I went to a lecture today, given by the president of the Illinois Institute of Technology. He was an engaging fellow, and spoke of his school's efforts to optimize both the aims and the means of undergraduate engineering education. Following his lead, I should note that the engineering field (through the good offices of the American Society of Engineering Education) has routinely sought to improve the content, methods, and presentation of engineering education. Every few years, serious people take a serious look at it, asking "What can we do better?", and (as important) "What shouldn't we be doing?" So, is the "standard American" model of undergrad engineering education a good one? This post will consider only two of the many options (just to keep it bounded). Should there be a "core curriculum" with discipline-specific branches, as I experienced? The upshots of this are that each student is armed with a standard,... read more
Three hundred years after Newton and Leibniz invented a vast mathematical structure and proceeded to bludgeon each other with it, people are still curious why calculus is so darn hard. The people who wonder that, however, are very often undergraduates or advanced high-schoolers, and they generally seem to think that, like freshman English, they ought to be able to breeze through calculus with a minimal amount of effort. After all, it's college, and who has to work in college? The American academic track and the psychical progression of American youth often collide violently at this point. Speaking only for myself, I had a blast my senior year of high school. I went off-roading, saw my friends a lot, and took as few courses with as much college credit as I could, figuring that I ought to make college as easy as possible. I went on to the business school at university, and was not disappointed. It was cake. Now you call it "networking" instead of "hanging... read more
Richard Feynman once said: "The problem of how to deduce new things from old, and how to solve problems, is really very difficult to teach, and I don't really know how to do it. I don't know how to tell you something that will transform you from a person who can't analyze new situations or solve problems, to a person who can. In the case of mathematics, I can transform you from somebody who can't differentiate to somebody who can, by giving you all the rules. But in the case of the physics, I can't transform you from somebody who can't to somebody who can, so I don't know what to do." This humble and frank assessment came from a man widely regarded as a fantastic teacher. It came in a review lecture available in "Feynman's Tips on Physics" (Feynman, Gottlieb, & Leighton; Pearson-Addison-Wesley; 2006), a supplement to "The Feynman Lectures on Physics", one of the most fascinatingly thorough digests of undergraduate physics. However, Feynman... read more
I am taking a course on combustion this semester, which is a lot less exciting than it sounds. Sort of. Combustion is one of those topics where you use incendiary language (ha-ha) to describe phenomena that end up being duller than their advertising. Explosion limits? The time it takes for a fuel mixture to ignite under certain conditions (like those kerosene-soaked rags you put in the trash can in the sun). Combustion bomb? Yep, it's a sphere with two windows where you get to watch very small explosions develop very symmetrically. But enough ragging on the hype. It is a very interesting class, nonetheless. One of the biggest takeaways so far is the power of approximate modeling. We often come upon complicated terms, but we very rarely carry them forward. Why? Because we don't need to. How come? This question draws the line between an experienced experimental engineer and an overeager graduate student theorist. All of the math that comes out of the combustion... read more
There's an interesting concept in thermodynamics called "exergy". It's not one that comes up often in daily use, like energy (how much the molecules want to move), or even entropy (how much of that energy you lose and can't get back, per temperature). No, exergy is kind of an odd duck, because it's relative. Let me explain. There was a problem I had in my homework with a car fueled by liquid nitrogen. An odd concept, for sure, unless you think about it in terms of "how different is my system from its surroundings?" For example, you can be at the top of the Space Needle, and if you were to, say, lower a weight on a rope that turned a generator, you'd get some work out, corresponding to the height of the Space Needle. Now, instead, imagine yourself standing on the ground at the mouth of a shaft mine with the same apparatus. You can still get work out, because you can still lower the weight. It all depends on the relative height of the start and end point,... read more
Everybody knows what a rocket is, right? Rockets are the big white cylinders strapped to the sides of the shuttle gas tank, and they're the black nozzles on the back of the shuttle itself, right? Quite correct, but do you remember Deep Space 1? This long-range probe used an engine that looked and behaved quite a bit differently than you might expect. After all, what makes a rocket? Is it the shape? The propellant? The use we put it to? Very simply, and perhaps boringly, a rocket is defined by the way we do the math. Let's look at Newton's second law in its general form F=d(m*v)/dt. If that doesn't mean anything to you, don't panic. All it says is that the Force on an object is equal to the time rate of change of the quantity (Mass times Velocity). So, force is related to how we change two things, mass and velocity, ok? Many people (freshman engineering students) who use the second law just jump a few steps and say F=ma, where they've shortcutted by saying the mass... read more
Does anyone recall the caloric theory? It was abandoned intellectually in the mid-eighteen-hundreds, but lives on in most introductory discussions of heat transfer. In it, heat is referred to as "caloric fluid", and is a massless, inviscid substance which has the capacity of permeating all bodies. Temperature was a measure of its density. It's where we got the notions of "heat flow". You put a hot body on a cold one, the highly dense caloric in the hot body flows down into the less dense region of the cold body, until they've equilibrated at a uniform caloric density. Nice, huh? This theory functions very well for heat conduction in solids, it gets along alright for convection in liquids, but boy does it choke on radiation. And yet the language we use about many heat transfer phenomena derives from this theory. Why? A theory is not reality. This is what we must keep in mind if we are to profit by them and not be tied to them. A theory is what we... read more
I don't really like the term "engineering ethics", because it implies that right and wrong may only be defined within the scope of a discipline, but as it is the term du jour, oh well. As an undergraduate, you get a few courses here and there that touch on "engineering ethics", or maybe a special class devoted to it, and most all the kids I knew kind of blew it off. It was an easy class, you just BS a paper or two about a famous disaster, and how the engineers were to blame, and you get an A. Then you graduate, go out into the workforce, and start playing the CYA game. You may not like to hear it, but that's a pervasive theme in modern business. You don't ask "How can I make this situation right?" You ask "Who is on the hook for this, and how can I make it NOT ME?" That's not honesty. That's not engineering. Insofar as you deal with hard facts, careful estimates, and the reality of universal physical laws, you're on the... read more
From late evening on August 12th to early morning on August 13th, you will have the opportunity to attend one of the greatest shows on Earth. Well, not exactly on Earth, per se, but up in the mesosphere. Some 30-50 miles above your heads, debris cast off from comet Swift-Tuttle will enter the atmosphere, pass through the very sparse thermosphere, and collide with gas particles in the relatively denser mesosphere. Fragments of rock and dust will leave their bright tracks for an instant on the night sky. Details- Doors open when the moon sets, around 9pm (best viewing after midnight), no cover charge, all ages welcome. Look northeast, around the constellation Perseus. Happy Perseids Meteor Shower!
My wife sometimes jokes that engineering is less a profession than a condition. If you're wired a certain way, you end up fiddling with pens at your desk, taking apart your phone because you're bored, and reflecting on how you could really use some Legos right about now, because you had a really cool idea and you wanted to see if you could build it. "Wanted to see if you could" could very well be the motto of science and engineering. The scientists want to see if the universe does a certain thing in a certain way, and the engineer wants to see if the universe can be used in a certain way. It's a really neat world we live in, and it's a lot of fun to examine it and use it in constructive ways. Anyhow, just some thoughts that may hopefully encourage folks who wonder "why bother with all this science stuff? What's it good for?" It comes back to "wanted to see if you could". Happy hunting!