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.
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.
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 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.
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.
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.
With a sheaf of drawings in one hand and a felt marker in the other, I wandered through the plant. It was stinking hot, but I'd rather be out here than in the air-conditioned trailer; I had to be outside anyway, and every stop in the trailer is one more shock to the system that I didn't need. Acclimatization makes the temperature easier to bear, but not all of my co-workers believed that and they kept the office trailer cold. I know colds are caused by viruses, but the co-worker who spent the most time in the trailer and turned the air conditioner the coolest was also the only one of the crew who caught a cold.
The pipefitters had almost finished with the large pipes, and would be starting on the small pipes soon after, which is why I was out with the marker. Nobody told me in school that felt markers would be an important part of the engineer's toolkit.
Since any given tank might have a half dozen ports all the same size, and some of them are very specifically placed where they are for a reason, they can't just be hooked up willy-nilly. This was why I was standing on top of a tank in the hot summer sun this time. No gas masks needed this time, fortunately, as this was still a construction site and nothing toxic had been introduced anywhere yet.
I'd study the tank drawing for the tank I was standing on, re-verify that the ports were all placed and sized properly, then kneel beside a port and write the port number and connection beside it with the sharpie. After burning my knees on the sun-hot metal of the tanks, I'd tug my pant legs up so the holes weren't directly under my knees. Nobody told me in school that burnt knees were a hazard of the field, either!
I marked every single port, and killed more than one marker doing it. Not so much that it was a giant plant, as the markers just didn't last long, writing on hot metal out in the sun—maybe a tank and a half to two tanks per marker. Tedious jobs are part of engineering, and while I don't particularly enjoy them, it is good to just put your head down and plow through them and then they're done. And, in this case, once finished I wouldn't be interrupted repeatedly by the pipefitters asking me which pipe went where.
The next day, as I wandered around the plant to see the piping progress, my markings had faded dramatically. It wasn't many days until they were nearly gone. Well, I tried.
Here's a nifty new piece of technology from Stanford University for any ocean-science types: a hydrophone that can be used at any depth which has low-distortion sound detection over a dynamic range of 160dB and a frequency range of 1Hz to 100,000Hz. By contrast, the human ear can hear a range of about 20-20,000Hz, feels immediate and acute pain at about 120dB—chronic damage starts much lower, down about 85dB. (If you want to know what 120dB feels like, stand about 3m in front of an emergency vehicle with its siren sounding.)
Most microphones have a thin diaphragm which vibrates in response to the sound waves hitting it, and this one is no exception. However, when you're detecting tiny pressure changes against the crush of a deep ocean trench, you need something that will not be overwhelmed by the ambient pressure. The answer for this particular microphone was to drill tiny holes in the diaphragm so that the water pressure on both sides of the diaphragm is the same. The holes would have to be small enough that sound waves in the water wouldn't pass right through them without moving the diaphragm, and large enough that the pressure would equalize before damaging the diaphragm as it's brought to depth. The diaphragm itself is about 500nm thick, so it is very fragile. To measure the movement of such a fragile surface, they use a laser. This is highly accurate and also doesn't touch the diaphragm with anything other than light. At the quiet end of the sounds they wanted to measure, and with water resisting the motion of the diaphragm, it moves only about 0.00001nm or so. Fortunately, lasers and mirrors can detect that sort of tiny movement.
Different sizes of diaphragms (and drumskins, and sound boards, and strings, and horn tubes) are most responsive to a particular frequency, so to cover the full range of frequencies they wanted to hear without distortion would be tricky with only one diaphragm. So, they put three different sizes of diaphragm in one microphone to cover the range.
Pin holes in my jeans, above the knee. How did that happen? I don't remember them being there before I put them in the laundry. There were a half dozen on each thigh, ranging in size from just a few broken threads to something I could put a pencil through.
I wore them anyway; they're my work grubbies, intended to get dirty or damaged.
While titrating a sample, I realized a possible route to those holes. The sample was about 2 litres; the chemical dropped in from well above the edge of the container. If micro-drops had splashed back out, unseen, and landed on me, the chemicals involved could have eaten holes in my jeans. But I hadn't noticed them until after doing laundry. After getting them wet.
Here's a funny paradox for you: 98% sulphuric acid is safer (or at least easier to store) than 50% sulphuric acid. Why? Because 98% doesn't have enough water in it to dissolve the acid and activate it. Not saying it isn't still very dangerous stuff: it is, and if water gets in the tank you're in trouble.
Maybe the chemical droplets stayed on my jeans until the water activated it enough to eat a bit of the fabric, until the wash cycle diluted it to the point where it couldn't do anything anymore.
I think it's time for a lab coat. Must ask the boss for one. It's safety gear!
Traditional medicines can be interesting things. Some don't work at all despite being widely used, but some, like the bark and leaves of willow (Salix), work very well and have been effectively used for millennia—there are written records from 500 BC referring to its use. More recently (the 1820s) the active ingredient, salicylic acid, was produced, then in the 1890s acetylsalicylic acid, what we know as modern aspirin or ASA, was created. Aspirin no longer comes from plants as willow trees can't grow fast enough to sate the world's appetite for painkillers, but is now synthesized from phenols.
Another traditional painkiller, a milkwood (Tabernaemontana) has been under investigation for several years now. According to the studies, it contains a mixture of several things, including compounds in the class of opioids (a painkiller type which tends to have undesirable side effects and which causes addiction) and conolidine, among many others.
The conolidine and other compounds were isolated and identified in 2004, but conolidine couldn't be properly studied at that time because they only managed to get a 0.00014% yield when purifying it out of the plant. In May 2011, a team of researchers from the Scripps Research Institute announced that they had not only managed to synthesize conolidine, they had also tested it on mice and found out that it had painkiller effects as strong as morphine, but without any of morphine's adverse side effects.