What do you call 3 EnPhys in a fume hood?

I’ve been sitting in an ETLC computer lab for quite a few hours here trying to write a computer simulation of the phys 397 lab that Rob Joseph and I have been working on for the last month. What should have ended up being a “straight line” passing through a nice series of 60 data points is actually a straight line passing through a jungle of randonimity. What I believe turned out to be our problem was that when we approximated our “filter function” (the transmission spectrum of the IR filters being used) we just used e as the base of the exponent. Assuming that a bell curve is accurately described by a gaussian distribution is something that loads of people probably do every day. I mean we did it every day for a month in Statistical Mechanics when we use the Stirlings approximation of large factorials. There are situations, and unfortunately our lab turns out to be one of them where a Gaussian just doesn’t describe a bell curve very well at all.

Indeed it’s the difference between something being gaussian and something being a bit wider up top or more triangular that throws our data for a loop. When performing the numerical integration right near the peak of the blackbody curve the filter is much narrower than the peak of the spectrum. This means that the variation from one filter to another across this regions is not
extremly pronounced. When the filter funtion is poorly approximated it makes a big difference!

What really needs to be done is to replicate the bell curve of the filter using a numerically exact model. Since I don’t have any means to do this I’m going to have to switch my beautiful 60 data point set into 10 data sets (ten filters) with only 6 data points each.

I was also going to pursue a reverse derivation of the plank curve using a 3D curve fit of my data array, that would have made my lab something close to a manifestation of sheer beauty on paper. But with these results I think it’s not going to be
worth the effort, I know that the answer will be poor.

I’m not all that worried about poor data, If I can write a blog at 12:50 am on a Friday night about the intricacies of a Gaussian Distribution, I’m not going to have any trouble filling 5 pages in Latex on the topic.

Quantum Mechanics is honestly the sweetest course I have ever taken in the history of my life. I’m now checking it off on my list of life goals as complete

Now, anybody else in the course right now might be thinking otherwise as we are all finishing up the largest “weekly” assignment of our lives. Mine totals 16 pages. But by struggling through some ridiculous matheMagic to do those complex integrals and expectation values etc. I’ve developed not only a greater interest in the stuff, I’ve really got a much larger respect for the whole deal.

When you start an integral on one page, and hack your way through it on 2 pages, making reference to another 4 pages of previous results for simplification along the way, and arrive at the finish line with an answer of h|bar*(l^2 + a). You really get a grip on how intricately everything fits together. Having started with an expression that was so long I couldn’t even write it on one line (and couldn’t be reduced from there either!) and can develop such an elegant result I’m beginning to get a bit better grip on how perfectly God has this world balanced out. Whether or not the quantum mechanics aspect of the problem characterizes the real world very accurately, the math itself is something that elicits a bit of awe in me. I can’t help but sit here at my desk and be in a good mood even though the clock now shows “12:50″ because I’ve just seen a few of God’s fingerprints.

Andrew and I spent a bonus 3.5 hours sitting in the 350 lab today working on our audio amplifier and it seems that we did nail it in the end. Our power amplification is well above the 1 million times specified in the manual. In fact, we pretty much maxed it out. Instead of doing like EE 340 where I figured out everything before I did it we decided to go for it and start building amplifier stages with the hopes that we could just tweak them into working correctly rather than actually calculating everything properly.

We started out by asking for maximum amplification from out MOSFET and found that we could get a voltage amplification of about 30 from it. Because it was impossible to drive our 8 Ohm speaker directly from the output of the amp we needed to put it through a BJT amplifier with a bit more reasonable of an output impedance. Anyhow, maximum power called for approximately 860 Ohms resistance on the drain of the FET, and this drove the BJT into clipping rather severly. Our simple solution to the problem was to decrease the amount of signal being coupled into the BJT by decreasing the efficiency of the FET, what started at 860 quickly became 560, then 480, 360, 240 and finally 150 Ohms. This amounted to a signal just clear of the level of clipping onset. And left us with well more than power amplification of 60dB.

Another curious note which we didn’t understand immediately, but soon got a handle on as everyone else in the lab was running into the same problem was a massive drift in power gain. It turns out to be no surprise at all that when a 100uF cap is in series with approximately 500K your time constant is a whopping 50 seconds! So evenif you let the circuit “warm up” for a minute you’ve still got a fractional drift of ~1/e to deal with after 2 minutes (1/e)^2 etc… Based on PSpice simulation I can drop that capacitance by a factor of 10 (or even 100) and not lose any bandwidth so it shouldn’t be a problem in the future (Time constant is 5 seconds (or 0.5)), just a funny story.

The Engineering physics club placed 4th in Geer Week 2007! We also managed to clean up in 3 events and the club room will be adorned with 3 pretty sweet-action plaques until January 2008! to check out some of the pictures from the week visit the Eng Phys Photo Gallery (click the thumbnail).

• 1^st Place – Scavenger Hunt
• 1^st Place – Godiva (Eng Week Newspaper)
• 1^st Place – Blood Drive

We scored Second in the Tech Display and placed far lower in the Design competition (5th) and the Movie (6th) than I think we deserved. Placement in other events can be found on the Engingeering Student’s Society Webpage.

Engineering week ends tomorrow with the 68th annual Engineers Ball. I would consider this one the most fun yet and would attribute that entirely to the fact that I went to essentially everything! I missed out on the Keg Races Obstacle course because I had a mandatory lab and I skipped out on the Wrap-Up party because I wasn’t interested in any of the bands playing there. What I did attend is nothing to be laughed at…

• Tug of War EP placed top 4
• Scavenger Hunt EP beat mecE, civE and EE.. all the big guns
• civE party
• Toboggan Races Had to borrow a female participant who incurred penalties for us =(
• Battle of the Bands
• chemE party
• Shangria First near-beer down and first to the bat… …last one back
• Design Competition Highest towerby far
• mecE party
• Movie Night Got to judge on behalf of our club, we certainly did good
• EE party
• Career Fair
• Beer Brewing / Boat RacesAnchored the team on one of the heats (5th place)
• Engineers Ball

I’ll find out tomorrow how we did in all these events and list our sweet achievements then. For now feel free to check out the EnPhys Gallery to see some pictures of the weeks events. Of special note are the ones involving shredded paper and club offices.

Rick Mercer visited the University of Alberta this past week and the segments were featured on “The Rick Mercer Report” today. The main feature is the pandas volleyball team but Rick also pays a visit to the NanoFab and cooks dinner using the flame throwers in Mechanical Engineering.

If you are like me and can’t be bothered to fit your life in around a TV schedule it’s also possible to check out the segment online. I don’t know how long it will be valid for… Probably at least a week but here’s the segment anyhow. The Rick Mercer Report Visits UofA

I’ll let your read the email correspondence between my prof and myself and let you judge the results for yourself…

FROM: Josh TO: Z.W. GortelI’m interested to come and have a look at my Physics 311 final exam. Is this possible?, I mean do you have it on file or is it locked up somewhere and unaccesible. I didn’t feel particularily confident with regards to my final exam performance and was a bit dissapointed although not entirely suprised with my grade (B+). After talking with a number of peers following the break they also thought they didn’t do very well on the final but still recieved excellent marks.

FROM: Z.W. Gortel TO: Josh Thank you for getting to me. It looks like we have a once in a lifetime bad luck with reporting. In fact, your grade is A+ (you had a second best final exam). I have, mistakenly transcribed this as B+ in my final report. Well, you can treat this as a New Year’s gift or come and kill me for causing you such an anxiety. I will correct the record (and check if I did not do a similar error with someone else). And, of course, you can come and see your final exam.

Engineering Week is now officially underway

I’m sure that attending class will be at approximately a rate of 60%. 75% if I’m lucky, I’m going to do my best to fit in a dozen events and meet the requirements for the beer fridge draw. Design competition, movie night, scavenger hunt, a couple parties and the noon events and I should be able to do it. Our progress is alright thus far, top 4 in the Tug of War (with a bunch of skinny nerds) is pretty impressive if you ask me.

Tuesday and Thursday this semester are certainly days that will teach me that even great things like physics need to be managed in moderation.

Hopefully this semester won’t turn me against it (I have little doubt that this is impossible) but I’ll certainly get my fill. Starting with Electrodynamics and then Quantum for 3 hours straight each morning I then roll right into 3 hours of labs in the afternoon. It’s a bit overboard but that’s just how the cookie crumbles.

I’m a little worried that I’ll get buried within a few weeks and won’t emerge until May.