Whom to believe December 5, 2012Posted by mareserinitatis in engineering, research, work.
Tags: engineering, engineering research, ideas, negative people, research
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I went to conference earlier this year in Tucson, Arizona. While there, I saw a lot of cool presentations, but one in particular really got me interested. I knew we’d done some work similar to this presentation, and it was obvious that there was some interest in the area. However, I wanted to come up with a different application so as not to be competing with work already being done.
When I came back, we did a lot of brainstorming, but couldn’t quite come up with anything. Or rather, it’s not that we didn’t come up with anything but that the practicalities of applying this solution to the application in mind had some serious issues. The idea sat for months in the back of my head, churning. Finally, about 3 months ago, I came up with a method to deal with the problems. I got together some people whose skills were required, convinced them my crazy idea might have some merit, and we started writing out proposals and white papers.
(Note: coming up with an idea less than two weeks before the opening of proposal windows for major funding agencies is NOT a good idea.)
Of the few people who have heard about this idea, they generally liked it and thought it was clever as well as pragmatic. (And here I feel like I’m doing well if I manage to hit one of those!) However, there was one person who really did NOT like the idea. In meeting with this person, they spent a good chunk of our meeting dismissing it and pointing out its flaws. I was feeling, after talking with this person, that maybe I’d made a mistake and the idea wasn’t terribly good. In fact, I really felt like they were suggesting the project was a waste of time.
Four days later, I got an email saying that the letter of intent submitted to one funding agency had been reviewed: they want a full proposal. I felt considerably better after that. However, rather than feeling entirely vindicated, I think I might want to sit down and take notes on the drawbacks and flaws that were pointed out. Hopefully, this will contribute to a better final proposal.
After that email, however, I’m not sure I believe that the idea is a total loss. I guess the funding agencies will let me know one way or the other.
Students finding their direction June 23, 2012Posted by mareserinitatis in education, engineering, geology, geophysics, physics, research, teaching.
Tags: engineering, geophysics, majors, math, physics, students
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The younger son’s birthday was this week, and we opted to host a pool party at a local hotel. (IMO, pool parties are the best for the elementary school age group: they keep themselves busy and then go home exhausted.) I was checking in when I noticed a young man standing at the other end of the counter. He looked familiar, so I asked if I knew him.
“I took your class last fall.”
“Oh great! How did the rest of the school year go for you?”
“Great. I actually switched to business and am really liking it.”
“Really? Why did you switch?”
“I just figured I liked business a lot better.”
“That’s why they have you take those early major classes – so that you find out you don’t like it before you get too far into it.”
I think the poor kid thought I would be mad that he had switched. But I wasn’t mad at all. If he feels like he’d be better off in a different major, then he ought to go for it. And that is part of what I’m trying to set out in the class – this is what engineers do. If it doesn’t look fun, then you ought to think about a different major. That’s a perfectly valid choice, and no one should judge a student for it.
(Yeah, I know…I sit here and wring my hands because older son gets these obnoxiously high scores in math and science but wants to be a writer…I’m one to talk.)
But seriously, I actually think it’s sort of silly to make students choose a major really early on in school. I think it’s a good idea to try to take a lot of classes in different fields before you really choose. I say this as someone who major hopped a lot during undergrad. I spent some time in physics, chemistry, journalism, and graphic arts. I finally decided that I liked physics after all, but what got me excited was geophysics. I happened to take a geology class when I was at Caltech because I had to take a lab course, and everyone told me geology was the easiest. Turns out, I really liked it and did very well in the course. (Of course, later on, I found that geology feels too qualitative and prefer geophysics, so it all worked out. On the other hand, I think I would’ve liked geology better if it had all been field courses.) :-)
I have run into people who got upset with me for this type of thing. I was doing research with a professor in undergrad, but I felt like the research wasn’t going well and got sort of excited about a math project that I’d seen a professor give a talk about. I talked to that professor to see if he’d be interested in having me as a student, which he was. When I told the other professor that I was going to work with the math professor, all hell broke loose. (I still think I made the right choice, though, especially since the first project really never did go anywhere.) I have yet to figure out why the first professor got upset, though, and did some petty stuff, like kicking me out of the student office (despite no one needing a spot) and having the secretary take away my mailbox. (This was silly, BTW, as I was president of the Society of Physics Students, so she ended up giving it back to me a month later so I could get SPS mail.)
And what did this do? Certainly reinforced that I didn’t want to work with this person, but I could also see it making a student feel like this person is representative of a particular field. Wouldn’t you wonder if a student would not want to go into a major because of the way the professors treat him or her? I can (and did!), and it just shows how ridiculous the whole thing was.
No, students need some time to explore their interests and getting mad at them for not doing what you think they should do is silly. They are the ones who have to deal with the consequences of their choices, and if a student takes my class and decides they don’t want to spend the next five to ten years of their life studying engineering, then I think they’ve learned something very important and just as valid as anything else I have to teach them.
Repost: Microwave Unsafe or Unsafe Microwave June 22, 2012Posted by mareserinitatis in electromagnetics, engineering, food/cooking, science.
Tags: cooking, engineering, food, microwaves
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(Note: this is from the old blog, back when living in Minneapolis)
There’s nothing like a nice, hot cup of English Breakfast or Earl Grey in the morning…until you reach into the microwave and burn your hand on your mug.
I’ve noticed something very irritating. Since I moved into my new place, all of my dishes get hot and some of them have cracking glaze after use in the microwave. The most irritating thing, aside from the pain, is that I’ve noticed my favorite mug is expanding and shrinking. It expands when heated and then contracts as it cools. This, unfortunately, has caused my tea basket to get physically stuck in the mug, which never happened with my old microwave (thus eliminating the notion that heating of the basket causes it to expand and get stuck).
Traditionally, this means that my dishes are not “microwave safe”. In other words, there is something in the dishes that heats up when put in the microwave. That means that you can destroy the dishes and burn yourself.
It wouldn’t be that big an issue except that all of these dishes worked fine in my other microwave back in Fargo.
This has led me to look into what might be causing the problem. Hypothetically, if something is microwave safe in one microwave, it should be that way in all microwaves.
There are lots of places that give you the basics of how a microwave works. A brief overview is that it emits electromagnetic waves which cause water molecules in food to rotate. The frequency of most commercial microwaves for the home is around 2.45 GHz, which is apparently a good frequency to get water molecules to “flip”. Flipping, rotating, shaking are all ways that molecules move, and molecular movement translates into heat. So the microwave makes all these water molecules do their jig because it excites them at just the right tempo. If you try exciting them at a different frequency or tempo, the water molecules won’t respond as well.
It’s harder to find information about how microwaves create these fields. It turns out that they generate electromagnetic waves with something called a magnetron. (An excellent and quite detailed description of how they work can be found here. According to The Art of Electronics, magnetrons fall under the category of “exotic devices”. This is probably code for “uses an electromagnetic field in a non-obvious way” or maybe “doesn’t always use silicon to do its job”. Interestingly enough, these are the same devices used to create fields for radar, including the Doppler radar that is used to look at cloud cover and precipitation. (If you’re a Wunderground nerd, like me, you spend a lot of time looking at images generated by Doppler radar.)
Again, I’ll summarize. There is a cathode (something which generates electrons) running down the middle of a cylindrical chamber. The chamber is subdivided into resonant chambers. Resonant chambers are areas where electromagnetic energy creates a standing wave. (A good though not exact analogy from sound, which is also a wave, would be an organ pipe.) The electrons formed around the cathode form into groups which spin and sweep past the resonant chamber openings. Because moving charge creates an electromagnetic wave which becomes a standing wave in the resonant chambers. This wave then creates a current in a wire or “feed”, which conducts a current to a waveguide. A waveguide is basically a replacement for a wire. It conducts an electromagnetic field when the power is too high or you could easily lose too much power through a wire. (Wires can be awfully lossy.) All it looks like is a rectangular tube, but the size of the tube is important because this will determine the frequency of the waves it can carry. (Remember, we want to have things pretty sharply focused at 2.45 GHz.) This tube leads into the microwave chamber which is tada! a Faraday cage. This is something that will contain electromagnetic energy inside of it without letting it escape as well as keep electromagnetic energy from your surroundings out. In this case, we want the energy inside. Waves which don’t hit our food will hit the side of the chamber and bounce around until it hits the food.
That metal screen is part of the Faraday cage and is keeping your brains from being baked when you’re pressing your nose to the glass going, “When will it be done?!”
Many microwaves contain things that look like fans but are actually “mixers” or “stirrers”. They cause the waves to bounce more randomly and create a more even distribution of the waves for heating. When the waves hit your food, they can only penetrate to about an inch. How far the wave goes into the food is quantified by something called a “skin depth”. Because your food isn’t a good conductor (like copper) which has pretty much no penetration depth, you will often notice that things get hot on the outside but not on the inside, like often happens to me when I reheat lasagna.
Food is also not a pure dielectric (like air or styrofoam) where the wave passes through and can’t generate a current inside. Food which is more conductive (which will likely have more water) will tend to heat up better or faster (as well as internally distribute that heat better) than food that doesn’t. Conductive food will also tend to have more water. In this case, you may be heating up a fruit-filled pie. The pie filling has a lot of water and will heat up fast, but the crust doesn’t and doesn’t seem to get as warm. You bite in, expecting the filling to be the same temp as the crust but end up getting burned instead.
People who design fast food meals ought to consult with microwave engineers on optimal heating set up.
As I mentioned before, microwave safe dishes don’t contain anything that will heat up when exposed to microwaves. Dishes which aren’t microwave safe contain some molecules that will be able to rotate, twist or vibrate in some way similar to water, causing the dish to heat up.
Sometimes you have dishes which are “thermally conductive”…that is, they transfer heat well. While you’re heating up your food, the dish is pulling a lot of that heat away from the food and into itself, causing the dish to get hot.
However, that doesn’t seem to be my situation. My previous microwave was much a higher power and seemed to heat up the food fine without heating up the dishes. My current one seems to do nearly the opposite. And since these are the same dishes, I have to conclude that it is in fact the microwave with the issue.
My first guess is one that doesn’t seem plausible. I don’t think it has anything to do with the size/shape of the magnetron or waveguide. Those are fairly large objects that can be mass constructed well within tolerances. I could be wrong, but that’s my initial guess. This also minimizes the chance that there may be some sort of mismatch between the magnetron and the waveguide.
Looking at the remaining possibilities, I’ve come up with three.
The first is that my microwave is poorly designed in the sense that it doesn’t direct electromagnetic energy well. This may be part of the problem as it seems to heat the dishes in areas away from the food. I don’t think that this is the entire issue because, if designed poorly, the wave should just bounce around until it hits something with high water content. However, I can’t say it’s not doing this.
There are two other possibilities. It turns out that magnetron frequency can change both with the temperature and the current through the cathode. Although the cathode temperatures get pretty high, I doubt that it would be that huge a change from a prototype once it gets over the initial change.
The last option seems most likely to me: the cathode isn’t working exactly the way it’s supposed to (which can be characterized by something called a “pushing curve”). If the current from the cathode is too high or too low, this will change the way the electrons behave, which will alter the frequency of the wave being generated by the magnetron.
In doing some research on my microwave, it turns out to have a horrid reputation. They die a lot, like within a year. Unfortunately, they’re so cheap that it’s not worth it to send them in for repairs because you have to pay for shipping to and from. When microwaves die like this, a lot of times it can be due to power problems, and thus the design of the controlling electronics or the high voltage power system can come into play. (Did I mention that magnetrons require huge voltages to operate???)
It appears that perhaps this line of microwaves may not have the best electronics design, and for whatever reason, the power into the magnetron isn’t quite right. This is causing my dishes to heat and expand while not heating my food optimally.
I guess I’ll be using oven mitts to take everything out of there until it decides to kick the bucket.
Tags: engineering, friday fun, Gigadog
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A friend posted the following video on facebook. I think I may use this with my class this fall, so they can get a good handle on the cool things you can do with control theory:
This is based on the following video created with computer animation. (I find it amusing that for so many years, we’ve been trying to master creating animation that looks real, and now Intel tried to make something real that mimicked an animation.)
Once you’ve finished watching those, you’ll want to check out the latest cartoon featuring Gigadog. (I think all Newf owners understand this one…)
Musings on research June 13, 2012Posted by mareserinitatis in career, engineering, grad school, papers, research, science.
Tags: engineering, engineering research, research, scooped
I made an interesting observation today. It’s funny that I should’ve noticed this before, but I didn’t.
I have finally come to the realization that the question, “How’s your research going?” is really a euphemism for, “How long until you’ve finished your PhD?” I’m not sure why it didn’t hit me before. My usual response to the question is to ask ‘which research?’ because I work in two totally different areas of research, both of which I find pretty fascinating. I thought the person asking the question was actually interested in what I was doing.
Nope. I realized today that they always say, “Why, your PhD work, of course!” And, when it comes down to it, only a handful of people who ask really are interested in the research itself. Most are just interested in how close that completion date is.
The reason I should’ve realized this before is because my husband got the question all the time. It didn’t occur to me until this line of thought became clear that once he’d graduated, people started asking, “How’s work?” (And usually, they aren’t interested in his research, either.)
If there isn’t a PhD comic strip devoted to this topic yet, there ought to be.
I got scooped. (A work related project – not my dissertation.) It was a small side project that I’d worked on here and there but had really not had any significant time to commit to. I’d gotten started on it and looked at things here and there. In part, I was waiting for someone else to finish some of his software development. (Of course, he was laid off earlier this year…so I imagine I’ll be waiting a while.)
Anyway, I am kicking myself because I obviously had a good idea (given someone else published exactly. the. same. thing.), but there was just no time to flesh it out. Did I make the right choice by focusing on other things or did I miss the boat? On the other hand…hey! I had a good idea. I, of course, have a couple of ideas of things that can be done based on the original project, but it’s disappointing that I won’t have the paper that gives the original idea. Of course, at the rate that particular project is going (because it’s so low priority…just some ideas I had playing around in the lab), I’m not sure I’ll ever get those other papers out.
This makes me wonder…is it good to focus on the ‘next big thing’? Or should one keep trying to work on those little things in the meantime? How do you prioritize? I think I made the right decision…but it’s easy to second-guess yourself.
The moment your heart stops beating May 25, 2012Posted by mareserinitatis in engineering, research.
Tags: bad results, engineering, engineering research, experiment, research
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I hate when I hear the words, “I need some help in the lab.”
I try my best, but I’m the last person you want in the lab. Therefore, if someone is asking me to help in the lab, you know there is a major catastrophe.
The other day I was asked to help in the lab because things weren’t working right. In fact, when I started looking at it, things weren’t working at all. While I hadn’t done the setup on this particular experiment, I was supervising it. So I had to run through the list of variables that could be affecting the results. It took a couple hours, but it turned out that some piece of equipment was being swapped out for another, and this new equipment simply didn’t work in the experiment. So we tried the original equipment again and it worked. New equipment didn’t. We tried a third piece of gear and found it worked, but only in particular situations where we spoke the incantations in a foreign tongue (or something similar).
Anyway, we figured it out for two of the three cases. However, when I first was looking at the non-working gear and not getting anything, my heart just stopped for a moment. It’s one of those moments where you think, “But I thought I knew what was going on? Did I completely screw up?! How could I have made such a huge mistake?!”
And of course the best one: “Does this mean ALL of my research is trash?!!!!”
I hate those moments, even if short-lived. Don’t you?
Review season May 7, 2012Posted by mareserinitatis in engineering, papers, research, younger son.
Tags: engineering, engineering research, papers, peer review, research, reviewer comments
Both Mike and I have been getting requests to review papers, and this has led to a lot of foul language around the house…along with frequent reminders from the younger son that our language is inappropriate.
It’s really hard to restrain yourself, however. As we’re sitting at the dining room table, occasionally one of us will turn our laptop toward the other and ask something like, “What does this look like to you?” or, “What do you think this means?” or, “What the hell were they thinking?”
I have to admit that I appreciate having a second pair of eyes to catch the things that I miss. I’m sure the authors of the papers we’re reviewing probably will not appreciate it. Not only do they have the third reviewer going over their papers, they have two of them. I hope this will result in double the hair pulling and teeth gnashing on their end…because it sure has for us.
When I was at the conference… March 13, 2012Posted by mareserinitatis in electromagnetics, engineering, physics, research.
Tags: conference, engineering, physics, research
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When I was at the conference last week, I had one fellow come up and look at my poster. He is working on a similar problem but in a different application, and he made some comment about how he definitely thought what I was doing had merit. (After seeing his talk, it made sense because he was trying something similar.)
However, we spent about 20 minutes arguing as to what we thought was going on in one of my plots. He kept suggesting something that I had ruled out with experiment.
Tonight I’m looking at papers on some theory related to this project, and I think I have managed to find the answer to that mysterious plot. Sadly, I was way off in my explanation, but I have to admit that apparently I wasn’t the only one. The fellow I was arguing with had it wrong as well.
The real answer appears to be way cooler than either of us thought. I love physics.
Doing before thinking January 3, 2012Posted by mareserinitatis in engineering, research, science, societal commentary.
Tags: engineering, INTJ, personality types, reflection
I like to plan. I like to work things out in my head before starting to do things with my hands. I’m an INTJ, and from what I understand, this is fairly common for people with this personality type.
It’s frustrating for me to see people do things when I’m not sure they know why they’re doing it. For instance, I was trying to work on a problem with a widget. Someone sent me some information on another widget which worked in a completely different way. Absolutely every component of colleagues widget was different from mine.
While I really appreciate the fact that someone is trying to help me out, I found myself putting a lot of time into trying to figure out how their data was going to help me. Was I missing something? Maybe one of the parts is really the same, so I can rule that out? Nope. Basically, the only thing that came of it is that the measurement device was working correctly. That’s certainly a good thing to know…but if it’s calibrated properly and regularly, that shouldn’t be a concern in the first place.
I guess if people want to spin their wheels taking useless data, that’s okay with me. However, it gets frustrating when I spend a lot of time trying to figure out what the point is, only to realize I just wasted a bunch of time on something that really didn’t help at all.
As much as I know some people are bothered by the time I “waste” thinking about taking, I guess it makes me feel better knowing that sometimes diving in head first without thinking can be just as much of a waste…and sometimes more.
The end is nigh December 10, 2011Posted by mareserinitatis in engineering, teaching.
Tags: engineering, teaching
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I’m through the ‘grading semifinals’: that is, I have no more grading until after the “all assignments are due” date on Monday. Unfortunately, I have a bad feeling about how this is going to go with some students. I have several students who handed in last minute assignments. It also appears they didn’t read the criteria for the assignment carefully and will not be getting credit for some of those assignments unless they redo them before Monday and submit them again. Some of these assignments are the required assignments.
I had structured the class so that there were six required assignments and 9 optional assignments. To pass the class, you had to do all required assignments. These included things like a personal essay, filling out a curriculum sheet so that the students knew how to plan what classes to take, a presentation on a subfield of engineering, how to keep a lab notebook, and how to write a lab report. The optional assignments involved a lot of metacognitive items like homework and test wrappers, a couple things on learning styles, a library quiz, and the dreaded Matlab assignments.
A couple weeks ago, I gave everyone a little piece of paper that showed what assignments were outstanding and what their current grade was. Realistically, this has always been available on blackboard. However, it was very disconcerting to see how many people were failing to turn in certain required assignments and thus were failing the course. This also led to an onslaught of homework that needed to be graded. What’s disappointing, however, is that a good chunk of these assignments were poorly done and didn’t fill the criteria outlined in the assignment. I had more than one student who handed in a lab report that was three paragraphs in essay form. No sections, no data, no cover page, etc.
I’ve never had to fail too many students in the past. In fact, the only one I can really recall was someone who did dangerous things during lab and then showed up to a makeup lab drunk. I guess facing the prospect of failing a large number of students (>5) is rather disconcerting. It makes me even more glad to get this over with, although I’m going to be very disappointed every time I have to put down an F.