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In the Future, Planes Could be Made with Self-Healing Materials

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Tiny cracks, the kind that you can't readily see, are big problems for planes. A scratch on the wing may go unnoticed for too long and eventually present a serious problem at the most inopportune time. To avoid the potentially catastrophic effects, researchers at the University of Bristol are working on a material for airplane wings that would "self heal."

The process works by embedding tiny spheres of liquid in the material used to make the wing. In the event of a scratch, those spheres would burst, releasing a carbon-based substance that would react with catalysts—also built into the wing material—to harden and seal the crack. The process is similar to what happens when you get a scratch on your body: blood pools into the wound and hardens into a scab to seal off the damage from your environment.

"Composite materials are increasingly used in modern airlines, military aircraft, and wind turbines. They are very stiff and strong but very light," researcher Duncan Wass told the BBC of existing airplane material. "That's perfect for aerospace...but the problem is if they are damaged, they are difficult to protect and repair. Our technology would enable you to maybe extend the maintenance schedule or use less material without compromising safety."

The repaired wing will be just as sturdy as the undamaged original, and the scientists predict the self-healing model will be introduced in the next five to 10 years.

While the researchers are focused on airplanes for now, once the technology is perfected and made more cheaply available, the applications are vast: Cars that don't scratch, cellphone screens that don't crack, offshore wind turbines that don't need as much costly maintenance. (Scientists are already working on self-healing concrete.)

"Basically, any industry which uses carbon fiber composites could benefit," Wass told Forbes. "At the consumer end of the market that could be sports equipment, bike frames, and so on."

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Hawaii's Kilauea Volcano Is Causing Another Explosive Problem: Laze
Mario Tama, Getty Images
Mario Tama, Getty Images

Rivers of molten rock aren't the only thing residents near Hawaii's Kilauea volcano have to worry about. Lava from recent volcanic activity has reached the Pacific Ocean and is generating toxic, glass-laced "laze," according to Honolulu-based KITV. Just what is this dangerous substance?

Molten lava has a temperature of about 2000°F, while the surrounding seawater in Hawaii is closer to 80°F. When this super-hot lava hits the colder ocean, the heat makes the water boil, creating powerful explosions of steam, scalding hot water, and projectile rock fragments known as tephra. These plumes are called lava haze, or laze.

Though it looks like regular steam, laze is much more dangerous. When the water and lava combine, and hot lava vaporizes seawater, a series of reactions causes the formation of toxic gas. Chloride from the sea salt mixes with hydrogen in the steam to create a dense, corrosive mixture of hydrochloric acid. The vapor forms clouds that then turn into acid rain.

Laze blows out of the ocean near a lava flow
USGS

That’s not the only danger. The lava cools down rapidly, forming volcanic glass—tiny shards of which explode into the air along with the gases.

Even the slightest encounter with a wisp of laze can be problematic. The hot, acidic mixture can irritate the skin, eyes, and respiratory system. It's particularly hazardous to those with breathing problems, like people with asthma.

In 2000, two people died in Hawaii Volcanoes National Park from inhaling laze coming from an active lava flow.

The problem spreads far beyond where the lava itself is flowing, pushing the problem downwind. Due to the amount of lava flowing into the ocean and the strength of the winds, laze currently being generated by the Kilauea eruptions could spread up to 15 miles away, a USGS geologist told Reuters.

[h/t Forbes]

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Big Questions
Do Bacteria Have Bacteria?
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Drew Smith:

Do bacteria have bacteria? Yes.

We know that bacteria range in size from 0.2 micrometers to nearly one millimeter. That’s more than a thousand-fold difference, easily enough to accommodate a small bacterium inside a larger one.

Nothing forbids bacteria from invading other bacteria, and in biology, that which is not forbidden is inevitable.

We have at least one example: Like many mealybugs, Planococcus citri has a bacterial endosymbiont, in this case the β-proteobacterium Tremblaya princeps. And this endosymbiont in turn has the γ-proteobacterium Moranella endobia living inside it. See for yourself:

Fluorescent In-Situ Hybridization confirming that intrabacterial symbionts reside inside Tremblaya cells in (A) M. hirsutus and (B) P. marginatus mealybugs. Tremblaya cells are in green, and γ-proteobacterial symbionts are in red. (Scale bar: 10 μm.)
Fluorescent In-Situ Hybridization confirming that intrabacterial symbionts reside inside Tremblaya cells in (A) M. hirsutus and (B) P. marginatus mealybugs. Tremblaya cells are in green, and γ-proteobacterial symbionts are in red. (Scale bar: 10 μm.)

I don’t know of examples of free-living bacteria hosting other bacteria within them, but that reflects either my ignorance or the likelihood that we haven’t looked hard enough for them. I’m sure they are out there.

Most (not all) scientists studying the origin of eukaryotic cells believe that they are descended from Archaea.

All scientists accept that the mitochondria which live inside eukaryotic cells are descendants of invasive alpha-proteobacteria. What’s not clear is whether archeal cells became eukaryotic in nature—that is, acquired internal membranes and transport systems—before or after acquiring mitochondria. The two scenarios can be sketched out like this:


The two hypotheses on the origin of eukaryotes:

(A) Archaezoan hypothesis.

(B) Symbiotic hypothesis.

The shapes within the eukaryotic cell denote the nucleus, the endomembrane system, and the cytoskeleton. The irregular gray shape denotes a putative wall-less archaeon that could have been the host of the alpha-proteobacterial endosymbiont, whereas the oblong red shape denotes a typical archaeon with a cell wall. A: archaea; B: bacteria; E: eukaryote; LUCA: last universal common ancestor of cellular life forms; LECA: last eukaryotic common ancestor; E-arch: putative archaezoan (primitive amitochondrial eukaryote); E-mit: primitive mitochondrial eukaryote; alpha:alpha-proteobacterium, ancestor of the mitochondrion.

The Archaezoan hypothesis has been given a bit of a boost by the discovery of Lokiarcheota. This complex Archaean has genes for phagocytosis, intracellular membrane formation and intracellular transport and signaling—hallmark activities of eukaryotic cells. The Lokiarcheotan genes are clearly related to eukaryotic genes, indicating a common origin.

Bacteria-within-bacteria is not only not a crazy idea, it probably accounts for the origin of Eucarya, and thus our own species.

We don’t know how common this arrangement is—we mostly study bacteria these days by sequencing their DNA. This is great for detecting uncultivatable species (which are 99 percent of them), but doesn’t tell us whether they are free-living or are some kind of symbiont. For that, someone would have to spend a lot of time prepping environmental samples for close examination by microscopic methods, a tedious project indeed. But one well worth doing, as it may shed more light on the history of life—which is often a history of conflict turned to cooperation. That’s a story which never gets old or stale.

This post originally appeared on Quora. Click here to view.

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