Today’s XKCD made me laugh out loud. Some problems are marketing and sales problems, not engineering problems.

Spinal Tap Engineering (Click to see original)

Units of measure are sooooo unnecessary.

Turkey. Representative of typical results.

This is where we start to run in to problems with the assumption that osmotic pressure is the mechanism behind turkey brining. We know from the brine recipe that there is about 1/2 cup of salt per gallon of water, which results in a 1.12 M solution. For comparison, physiological saline (0.9% NaCl) has a molarity of 0.156 M. If we assume turkeys have the same salt concentration as people, that leaves a difference between the brine and the turkey meat of 0.964 M. The big problem here is the direction of the offset. The higher concentration is in the brine, not the turkey meat. The pressure is in the wrong direction to force more H₂0 into the meat.

It turns out I’m not the first to ponder this question, and there is an alternate hypothesis.

The real answer has to do with the shape of proteins. In their natural state, the muscle cells are tightly bound within their protein sheaths—this doesn’t leave much room for excess water to collect in the meat.

But as anyone who has ever made sausages or cured meats knows, salt has a powerful effect on muscles. A 6% solution of salt will effectively denature (read: unravel) the proteins that make up the sheath around the muscle bundles. In this loosened, denatured state, you can now fit more water into those muscles than in their natural state. Even better, the denatured proteins in the sheaths contract far less as they cook, therefore squeezing out much less moisture.

So it turns out that denaturing proteins has a much bigger role in the effect of brining turkey than osmotic pressure.

I don’t think the knowledge will help you make a better turkey next year, but if you need something new to talk about at the Thanksgiving table, it might due the trick. If the guests fall asleep you can always blame the tryptophan.

From Make

The first rule of fight club is you do not talk about fight club

Math is always portrayed as exacting and calculating, but there is a great need for those that deal with numbers on a regular basis to also have a sense for approximate answers. Throughout engineering school it is often referred to as “back of the envelope” calculation. Quick and dirty approximation that gives a sense of the exact answer.

A colleague pointed me to a class called “Street-Fighting Mathematics” over on the MIT Open Course Ware site. MIT OCW is a site with lecture notes, readings, exams and videos from quite a few classes. Now you have no excuse for sitting around doing nothing on a Friday night! Street-fighting Mathematics is taught by Sanjoy Mahajan, and it looks pretty well put together.

The course description reads:

This course teaches the art of guessing results and solving problems without doing a proof or an exact calculation. Techniques include extreme-cases reasoning, dimensional analysis, successive approximation, discretization, generalization, and pictorial analysis. Applications include mental calculation, solid geometry, musical intervals, logarithms, integration, infinite series, solitaire, and differential equations. (No epsilons or deltas are harmed by taking this course.)

Seems to be the thing everybody should review every once in a while. Here is your first assignment, now get to work!

While it something that I would not mind reading some day, I really only mention it so that I can link to the YouTube video of the lecture Pausch gave for the Last Lecture “Achieving Your Childhood Dreams”. Watch the whole thing, you will be a better person for it. The insights and clarity are not often available like this.

Below are a few of the images captured during the course, during the bullet lab. It consisted of taking still images with a 500 nanosecond strobe of (what else?) .22 bullets going through things. These were taken in a dark room with the camera shutter open, and a microphone trigger for the strobe. I re-hosted these and others in the general photography section of this site and in addition you can find them on the Edgerton Center Site, along with others from previous years.

The course was great, split about 50-50 between lectures and laboratory work, starting with the basics of high speed photography and touching on some of the most advanced technologies that are just being released commercially. In the four days of the class we covered a wide range of useful topics:

• Camera and Setting Selection
• Lighting
• Lens Selection
• Laser Illumination
• Schlieren Imaging
• Motion Analysis Software

The 32+ course attendees were split into four groups and assigned a rather tongue in cheek project to be presented at the dinner the final evening of the course. This was a competition between teams, with prizes for the team with the “best” presentation. The point was to demonstrate some of the principles that were learned in the class, but also included points awarded for originality and entertainment. I won’t divulge details of what happened, but these were some of the funniest presentations I have ever seen. For some reason there were quite a few high speed video clips of people being hit in the head with things (including hot dogs and balls of clay). My group didn’t win the competition, but I must admit that the team that won earned every bit of it.

So many thanks to Dr. Jim Bales for the great course and the chance to have a little fun while we were at it!

* The Miracle of Science is a bar and grill about 3 blocks from MIT. Very much a tech college decor, the menu is nicely done as a periodic table on a chalkboard (I had the Rony Burger, chemical symbol “Rb”), and the bar and tables are the black lab surfaces that we all remember from chemistry lab.

The conference venue was a hospital that was located about six or seven kilometers from the hotel, so I quickly learned the layout of the subway system in order to get back and forth each day. The hotel was close to the center of town, so there was a chance to see the Rathaus and wander around downtown each night.

One slow afternoon, I made it to the Deutsches Museum, by far the best science and industry museum I have ever been to. I could have spent days there.

After the conference was over, I spent my last afternoon in Munich vistitng the Olympic Park, and seeing where baby BMWs are made.

It was a nice trip, I really enjoyed Munich. Next time I’ll have to bring the family and spend some extra time.

It looks like that future we have heard about has arrived. At the Greener Gadgets Conference in New York, there was a Bluetooth enabled touch screen that is designed to be inserted between the skin and the muscle. That’s right, an animated and interactive tattoo. But that is not the awesome part.

The basis of the 2×4-inch “Digital Tattoo Interface” is a Bluetooth device made of thin, flexible silicon and silicone. It´s inserted through a small incision as a tightly rolled tube, and then it unfurls beneath the skin to align between skin and muscle. Through the same incision, two small tubes on the device are attached to an artery and a vein to allow the blood to flow to a coin-sized blood fuel cell that converts glucose and oxygen to electricity. After blood flows in from the artery to the fuel cell, it flows out again through the vein.

It runs off energy from your blood. How cool is that.