Simulated Failure

Simulating normal operation is something that's been done for a while now, ever since computers got powerful enough to do it. Once validated, a model of, say, a stirred tank, will let an engineer consider where two liquids being mixed are not mixing properly, or where fragile solids are likely to be broken because the shear is high, and adjust the design accordingly before the manufacturer ever cuts metal.

I started by talking about fluid dynamics simulation because that and chemical reaction simulation are the two aspects I'm most likely to work with. Other simulations which could affect me but are outside of my field are materials and mechanical related - pipe and tank fractures, for example. The stresses and weak points of a piece of equipment are something I have to trust to a mechanical engineer, but I have to think about it at least a bit, because what's inside those tanks and pipes is sometimes hot, sometimes toxic, sometimes corrosive, or other forms of dangerous and undesirable to have present outside the equipment, and I have to know what kind of safety features and procedures I have to put in place, from sensors to detect a small leak to secondary containment to prevent a catastrophic spill from escaping and doing even more damage.

Splat!

Figuring out where a spatter came from is useful sometimes. Not in any field I've personally worked in, but then I don't usually work with things that go splat. Some things which go splat, where the spatter marks remaining after the fact are the only evidence available to figure out how exactly it happened, include volcanoes (which can make very big, very dangerous splats most sane people wouldn't want to watch in person) and people being attacked (which often ends with the source of the spatter in no condition to describe the attack).

One obvious thing about spatters is that the individual marks are ovals, and they point in the direction of their source. This has been known for a long time now, and has been used in forensics to determine where a victim was. It could also be used for volcanoes, if nobody saw which of the vents erupted due to running for their lives.

What the oval spatters didn't accurately point to was how high the source was.

Biodegrading ... into what?

"Biodegradable" is one of many words commonly used to indicate something is environmentally friendly, but like many technical terms, it often doesn't mean the same thing in common usage as it does to a scientist. To me, "biodegradable" just means that the substance in question can be processed by some biological route into some other, usually lower molecular weight, substance.

It says nothing about the toxicity or harm—or benefit—that might be caused by the new substance.

The Chocolate Process

Chocolate, as you probably know, comes from cocoa trees, but to get from the tree to edible chocolate takes a fair bit of processing. In short, the cocoa beans are removed from the pod, fermented, dried, roasted and shelled, ground, and sweetened.

I can understand why ancient people paid any attention at all to these seed pods; when you cut through the thick rind, the white pulp the seeds are embedded in is delicious straight off the tree. However, the seeds are pretty bitter and nasty tasting when raw. How did they ever go from "suck on this but don't crack the seed open" to "ferment+dry+roast+grind+sweeten = delicious"?

How much does a cloud weigh?

I was chatting with a friend not long ago, and he mentioned that he sometimes pictured clouds as these malevolant, multi-ton monstrosities hovering overhead, just waiting to smash down on us tiny humans. And by the way, how much does a cloud actually weigh?

Clearly, this calls for some math: I decided to calculate how much a cloud actually massed.

I started out by finding a cloud that I could measure reasonably well.

Nanostamp

Nano-scale devices have been around for a while now, filling functions such as chemical sensors of extraordinary sensitivity and selectivity, your computer's CPU, and the read/write head on the hard drive. There has also been a lot of progress on what people would recognize as nanomachines, too: motors, gears, switches, all on the nano-scale.

In most cases, however, they're still difficult to make, using the same sorts of high-purity, cleanroom processes as for computer CPUs. Yes, those are in mass production as evidenced by how there are computers in everything these days, right down to doorknobs, but it's still an intensive process requiring extreme purity and cleanroom procedures.

Until recently, that is: some nanoscale devices can now be made easily, even with something as crude as a tabletop vise. Plus, the crucial part, a stamp.

The stamp was made using the cleanroom process, and once complete it can stamp out multiple copies of the actual device outside of a cleanroom, which makes them much cheaper and faster to produce.

One thing that is particularly interesting to me as a chemical engineer is how simply changing the coating on the nanostructured surface (for example, a tiny diffraction grating) changes what chemicals it detects (or more specifically, what chemicals stick to it). Then, on shining a light on it, the presence of those stuck chemicals changes the reflection or diffraction pattern in a way that's proportional to the amount of chemical adsorbed. And, moving outside of my field of expertise, biological molecules can be very specific in what will stick together and what will not. There's a lot of work going on to make these sensors to detect specific enzymes or enzyme activity that are characteristic of a disease, antibodies, and even parasites.

Making these sensors faster and cheaper means that development of useful tests for hospitals, and maybe eventually your GP's office, will speed up dramatically.

Life-giving crystals

Another piece of the puzzle that is life has fallen into place, and it is a spiky crystal.

That right there is one powerful crystal: it is the chemical precursor to RNA, the earliest self-replicating molecule that science is aware of, and thus the starting point for life. It grew from a mixture of basic, common organic chemicals in the presence of a few common amino acids, and is stable and will stay put until the next step, converting it to RNA, takes place.

Not only that, but it's the correct form of the two possible enantiomers that the RNA precursor can take, and it grew naturally out of a mixture of chemicals that didn't start out composed of the pure correct enantiomer, but of a racemic mixture plus a nearly racemic mixture of amino acid that had only 1% excess of the enantiomer they wanted.

I am not a flower

I was on a job site, walking outdoors, when something small and bright moved near my shoulder. My first reflex was to swat at it; there are no lack of wasps around here. Fortunately I managed to stay my hand when I recognized it—a bright yellow butterfly, exactly the same colour as my yellow safety vest.

It landed on my vest, took off, landed, took off, and kept doing that for about a minute.

"Sorry, butterfly, I'm not a flower," I said to it, standing still next to the reactor.

It landed on me a few more times, then eventually realized I wasn't actually a jackpot of a bright yellow flower, and flew away.

My co-workers probably think I'm crazy. I've rescued a ladybug from one of the tanks in the same plant. As it was walking all over my hand the way ladybugs do, one co-worker asked me why I was talking to a bug.

"I like ladybugs," I said. "They eat the bugs that eat my garden."

We've also rescued a small frog from one of the tanks, and chased another out of its daytime hiding spot inside a short length of 1/2" PVC before using it. On moving an orange road cone, another co-worker commented that he was going to go fishing, after catching some of the explosion of crickets that burst out when the sun hit them.

Despite all that, I don't like it when wasps build nests on my equipment. They're the only ones I'll get out the killing spray for—not because I have something against wasps, only that they can't be building nests on my equipment when people need to be working in that area. They can build their nests somewhere else. Unfortunately, convincing them not to keep rebuilding in the same spot requires that killing spray. I hope after hitting two nests they're getting the idea.

Inspired by: water striders

Here's another small robot that illustrates a fundamental property of physics. Like the Waalbot I mentioned last week demonstrated van der Waals forces, this one demonstrates surface tension.

Above is a water strider. Notice the dimples in the water where each foot touches the surface of the water.

Inspired by: geckos

This bit of news isn't actually all that new, but that's the nature of science: from discovery of physical principle to practical application takes a while.

So way back in the '70s, there was finally a microscope powerful enough to see what a gecko's hairy feet looked like. Because however they managed to climb polished glass, it wasn't glue, it wasn't suction cups, and it wasn't hooks or claws. This is what they found:

Yup, those are some hairy toes.