Electric Charge, Surfactants, Bubble Nucleation, and …

… Boiling of Water! Here’s a neat video about the work.

Here’s a quote from an MIT News story on the research:

“The whole concept relies on the fact that whether a surface is hydrophobic or hydrophilic will affect the rate of nucleation,” Cho says. “If it’s hydrophilic, it’s very difficult to nucleate bubbles.” So by switching the polarity, the rate of bubbling can be precisely controlled.

Unlike other approaches to modifying the wettability of metal surfaces, which rely on the creation of precise kinds of nanoscale textures on the surface, this system makes use of the tiny irregularities that naturally exist on a metal surface and does not require special processing.

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Hat tip: Alissa Walker at Gizmodo.

A Computational Look into Melting Predicts a Very High Melting Compound

This paper from Axel van de Walle’s group sounds interesting: Researchers predict material with record-setting melting point [see also this WaPo story]:

The experimental record-holder is a substance made from the elements hafnium, tantalum, and carbon (Hf-Ta-C). But these new calculations suggest that an optimal composition of hafnium, nitrogen, and carbon — HfN0.38C0.51 — is a promising candidate to set a new mark. The next step, which the researchers are undertaking now, is to synthesize the material and corroborate the findings in the lab.

“The advantage of starting with the computational approach is we can try lots of different combinations very cheaply and find ones that might be worth experimenting with in the lab,” said Axel van de Walle, associate professor of engineering and co-author of the study with postdoctoral researcher Qijun Hong. “Otherwise we’d just be shooting in the dark. Now we know we have something that’s worth a try.”

“The advantage of starting with the computational approach is we can try lots of different combinations very cheaply and find ones that might be worth experimenting with in the lab.”
The researchers used a computational technique that infers melting points by simulating physical processes at the atomic level, following the law of quantum mechanics.

Richard J. Light: “How to Live Wisely”

Harvard Graduate School of Education’s Richard Light talks about an interesting seminar/discussion course in his NYTimes column. The short course (more like a module running into several sessions) is built around a set of exercises which make the students not just think through their core values, but also consider situations where they might lead to conflicting conclusions. Here’s one of them:

This exercise presents a parable of a happy fisherman living a simple life on a small island. The fellow goes fishing for a few hours every day. He catches a few fish, sells them to his friends, and enjoys spending the rest of the day with his wife and children, and napping. He couldn’t imagine changing a thing in his relaxed and easy life.

A recent M.B.A. visits this island and quickly sees how this fisherman could become rich. He could catch more fish, start up a business, market the fish, open a cannery, maybe even issue an I.P.O. Ultimately he would become truly successful. He could donate some of his fish to hungry children worldwide and might even save lives.

“And then what?” asks the fisherman.

“Then you could spend lots of time with your family,” replies the visitor. “Yet you would have made a difference in the world. You would have used your talents, and fed some poor children, instead of just lying around all day.”

We ask students to apply this parable to their own lives. Is it more important to you to have little, accomplish little, yet be relaxed and happy and spend time with family? Or is it more important to you to work hard, use your talents, perhaps start a business, maybe even make the world a better place along the way?

Typically, this simple parable leads to substantial disagreement.

Chemical energy!

Suppose a typical modern family car does about 40 miles to the gallon or, in metric terms, 100 km for every 7 litres of fuel. That means if you have a teaspoon of petrol (about 0.004 litres), it contains enough energy to roll your car about 60 m (200 ft), or roughly 15 times the car’s own length. Consider how hard it is to push a car, even once you’ve got it going from a standstill, and I’m sure you’ll agree that’s quite remarkable. The simple fact is that petrol is absolutely chock full of energy: short of uranium (nuclear fuel), it’s just about the most energy-rich material there is. […]

That’s from Chris Woodford in his article, Why Your Car is a Chemistry Lab on Wheels (“What makes cars one of the most successful inventions of all time? The answer lies in science”).

Fabulous stuff!

Materials in Apple Watch

Here’s a fine piece —

How Apple Makes the Watch — on the materials (specidfically, gold, stainless steel and aluminum) and processes which go into making several key (but non-electronic) components of Apple watch. It uses publicity videos from Apple as a starting point, and describes some of the processing steps (and perhaps the science behind it) seen in those videos.

Strongest Natural Material?

David Schultz in ScienceShhot: Spider silk dethroned as nature’s toughest fiber:

Spider silk is famous for its amazing toughness, and until recently a tensile strength of 1.3 gigapascals (GPa) was enough to earn it the title of strongest natural material. However, researchers report online today in the Journal of the Royal Society Interface that the record books need to be updated to properly recognize the incredible strength of the limpet teeth. … [T]he limpets’ teeth boast a tensile strength of between 3 and 6.5 GPa, researchers report.


One more theoretical prediction about a supermolecule with 20 selenium atoms and 60 carbon atoms whose architecture resembles that of a volleyball (arXiv link to the paper):

The simulation gives a remarkably detailed picture of the properties of the new molecule. Jing and co have simulated the character of the bonds that hold it together, their binding energy, their vibrational frequencies, and the stability of the structure.

And they say volleballene is clearly the most stable of all the structures that Sc20C60 can form. The tam’s vibrational analysis suggests that volleyballene should be stable when heated and remarkably stable chemically too.

In other words, volleyballene is a molecule waiting to be synthesized.

Nerdy cartoons

We talked a little about nerdy cartoons in my class this morning. The topic came up in the context of a couple of quotes:

  • George Box: “Essentially, all models are wrong, but some are useful.” [This quote came up naturally in the context of the discussion on some of the (bad) implications of the underlying assumptions in a model that we were talking about].
  • Stephen Robbins: “God gave all the easy problems to the physicists.”. [This quote came up in the context of the need for simple models to study complex phenomena (such as those that we study in materials science); and nothing gets more complex than human behaviour studied by social scientists!] Here’s the context in which this quote appears (from the 15th edition of his textbook on Organizational Behaviour):

    Laws in the physical sciences —- chemistry, astronomy, physics—are consistent and apply in a wide range of situations. They allow scientists to generalize about the pull of gravity or to be confident about sending astronauts into space to repair satellites. But as a noted behavioral researcher observed, “God gave all the easy problems to the physicists.” Human beings are complex, and few, if any, simple and universal principles explain organizational behavior. Because we are not alike, our ability to make simple, accurate, and sweeping generalizations is limited. Two people often act very differently in the same situation, and the same person’s behavior changes in different situations. Not everyone is motivated by money, and people may behave differently at a religious service than they do at a party. [Bold emphasis added]

Which led immediately to a comment about every self-respecting academic has a healthy disdain for what others do. This disdain is expressed using some metric by which one’s profession can be “proven” to be better than the others; one such metric is purity (or, fundamental-ness) of one’s field, as in this absolutely great xkcd cartoon. Here’s a version of it in Abstruse Goose. This SMBC strip about a mathematician’s fantasy fight with a physicist is also a classic.

Elsewhere, I have a post on academic put-downs; and there’s a separate category on Interdisciplinary Wars right here on this blog.