The Mantis shrimp inspires a new material—made by bacteria

Photograph: Getty Images

 

From Wired 

 

By 3D-printing scaffolds and dipping them in microbe juice, scientists make robust structures that could one day lead to self-growing roads.

To humans, the mantis shrimp is known as the “thumb splitter,” due to its propensity to punch the digits of unfortunate fishers.
To its prey on the seafloor, the mantis shrimp is known as “death incarnate”—the crustacean cocks back its two hammer-like appendages under its face, releasing them with such force that they obliterate clam shells, one of the toughest materials in nature.
The mantis shrimp has even more fun with crabs, strategically blowing off their claws first so the prey can’t defend itself.

All that bashing puts serious stress on the hammers themselves.
So to deal with the constant punching, evolution gave the material of these weapons a “Bouligand” shape.
Instead of the layers of material neatly stacking one on top of another, the layers are twisted, almost like the helical structure of DNA.
So when a mantis shrimp’s hammer smashes into a thumb or a clam or a crab’s face, any crack in its structure will propagate in a twist pattern, dissipating the energy throughout the material.
As a result, the hammer doesn’t snap in half.

 

Neat, said engineers at the University of Southern California and the University of California, Irvine, who’ve invented a clever kind of material based on the mantis shrimp’s clobber-sticks.
(If you’re one for formal terminology, they’re called dactyls.) It’s a twist within a twist: They’ve been able to get minerals to grow within a 3D-printed shrimp-inspired Bouligand structure with the help of bacteria, of all things.

 

Courtesy of Qiming Wang

The researchers began by 3D-printing a simple lattice structure, basically a grid, out of a polymer.
As you can see in the image above, the resulting scaffold had plenty of empty space within—think of it as being like the beams that support a building.
They then dipped the whole structure in a bacterial solution and let it sit for 12 to 24 hours.
The Sporosarcina pasteurii bacteria in the solution attached to the polymer lattice and started secreting an enzyme called urease.

Courtesy of Qiming Wang

When the researchers dipped the structure into a second bath of urea and calcium ions, the urease kicked off a chemical reaction that created calcium carbonate.
This is the same material that gives a clam’s shell—as well as your own bones and teeth—their strength.
It’s also a component of the mantis shrimp’s hammer.
In the lab, as the researchers left the scaffolding in the solution, the calcium carbonate kept on accumulating, filling in the lattice entirely within 10 days, and giving the researchers a super-tough material made of a polymer skeleton and mineral innards.
You can see the structure’s progress in the image above.

Courtesy of Qiming Wang

The researchers were able to 3Dprint lattices with a variety of interior shapes, from wave patterns to crosses, as shown in the images above.
Row C shows where the mineral filled in gaps in the polymer skeleton.
In the colorful images of row D, you can see that calcium carbonate mineral deposits score high in stiffness (indicated in red), while the lattice ranks lower (shown in blue and green).

But what the researchers were really after was the Bouligand structure, which gives the mantis shrimp’s hammer its resilience.
In the image below, there are four different types of lattices.
Image A shows what those 3D-printed structures look like, with Type I being just a linear stack of material, while Type IV is the Bouligand structure—each layer shifts 45 degrees, creating a kind of swirl.
In row C, the images show the dark bands of polymer filled in with white calcium carbonate.
Type I is arranged like aisles in the grocery store, whereas Type IV looks more chaotic.

 

Courtesy of Qiming Wang

 

A good kind of chaotic, as it happens.
When the researchers tested the strength of each lattice, the Type IV Bouligand structure absorbed 20 times as much energy as Type I.
“This kind of microstructure makes sure that this kind of composite is very tough,” says University of Southern California engineer Qiming Wang, coauthor on a new paper describing the findings in the journal Advanced Materials.

“When you have a crack, that crack will propagate in the twist pattern to dissipate the energy inside the material.” In fact, the material absorbs more energy than natural nacre (mother of pearl), which gives some shells their strength, and also beats existing artificial materials, Wang and his colleagues say.

 

Just as the mantis shrimp’s hammer absorbs the energy of its punches without snapping, so too might materials developed with this new method.
For potential uses, Wang says to think of body armor, which needs to dissipate a bullet’s energy.
Calcium carbonate is also fairly lightweight, so scientists might also be able to grow tougher panels for aircraft or even skins for robots, Wang says.

 

“This is, for me, a way to do manufacturing in the future, and I'm not the only one saying that,” says Purdue University civil engineer Pablo Zavattieri, who wasn’t involved in this research.
In traditional manufacturing, defects can sneak in.
Nature, on the other hand, has, over the course of millions of years, developed the wondrous Bouligand structure in the mantis shrimp’s hammer, and it’s a pattern that can be replicated with a simple lattice and a bacterial bath.
“Nature is, in that way, impeccable,” Zavattieri says.
“Nature is a 3D printer.”

 

Another thing that makes this bacteria-built material special is its ability to regenerate.
Like, what if instead of building roads, we grew them? “If we have damage, you just introduce bacteria inside, and it can grow it back,” says Wang.
“These structures are very tough, very strong, and can potentially repair themselves.”

 

The researchers aren’t there quite yet—they got the bacteria to grow minerals in controlled conditions in the lab, and even then it was only in small quantities.
Scaling up for constructing roads would bring additional engineering challenges; for instance, getting the right ratio of supporting scaffold to hardening material.
But Zavattieri is actually already working on 3D-printing concrete.
“I don't think it's super crazy,” he says.
“We can totally have robots print the classic scaffold, leave the bacteria there, and then let them grow the material for 10 days.”
So perhaps one day the unabashed bashing of the mantis shrimp could help fix America’s busted infrastructure, instead of just breaking thumb.

 

Links :

• Physic World : Merging nature and engineering: mantis shrimp vision in the operating room

How high-tech robotic surfboards could change our understanding of the Gulf Stream

From WashingtonPost by Matthew Capucci

How high-tech robotic surfboards could change our understanding of the Gulf Stream
The ‘saildrones’ can go places that most science ships can’t

The Gulf Stream, the warm water current that weaves a serpentine path from the west Atlantic to the United Kingdom, routinely brews some of the most extreme winter storms in the northern hemisphere, disrupting shipping and marine commerce while affecting weather throughout the globe.

The Gulf Stream is also an enormous absorber of carbon dioxide, trapping greenhouse gases and preventing the pace of climate change from accelerating further.

Scientists are now hoping to gain a better understanding of what makes the Gulf Stream tick by launching “saildrones” — or surfboard-like “uncrewed surface vehicles” — that will ride the waters and transmit observations for up to a year.
Developed by the Saildrone company in Alameda, Calif., they are used to survey weather and ocean observations and can cover thousands of square miles with no carbon footprint.

“We had a competition where we asked what people would do if they had a Saildrone for a month,” said Anne Miglarese, Saildrone’s program executive officer for impact science.
Jaime Palter, a professor of oceanography at the University of Rhode Island, said she would “stick it in the Gulf Stream,” Miglarese recalled.

Saildrone was enthusiastic about the proposal.
It loaned Palter a unit that was launched from Newport, R.I., on Jan. 30, 2019.
Palter’s aim was to better understand how currents like the Gulf Stream fit into the global carbon cycle and how much of a net carbon sink, or absorber, they are.
Humans routinely emit more than 35 billion tons of carbon dioxide annually, about a third of which is believed to immediately end up in the oceans.

Recent Saildrone missions in the Antarctic have shown that the ocean’s role in the carbon cycle may not be as well understood as once believed, which could result in significant changes in how scientists model and research the dynamics of climate change.

“We circumnavigated the Antarctic last year on another philanthropic mission focused on monitoring carbon,” Miglarese explained.
“The scientific consensus [at the time] was that the Antarctic was a sink for carbon.
Our science showed it was a source part of the year.”

According to the paper published with the data, “observing the Southern Ocean is challenging due to its size, remoteness, and harsh conditions,” a problem that is also inveterate to the North Atlantic during winter.

The challenges of collecting data from the Gulf Stream motivated Saildrone to work with partners to explore the current’s role in the sequestration and release of CO2.
They’re partnering with NOAA, along with Palter, to analyze the findings once obtained.

“We need a more accurate global carbon budget, and missions like this one will support that and help test our assumptions,” Miglarese said.

A dramatic view of Hurricane Florence as seen from the International Space Station.

A tropical cyclone is a generic term for a rapidly rotating tropical storm with a low-pressure center and clouds spiraling toward the center of the system.

In the Atlantic, they are also called hurricanes; in the Pacific they’re called typhoons.

Photo: NASA Goddard Space Flight Center/Flickr.

With the help of a roughly $1 million investment from Google, Saildrone will be launching a half dozen of its drones to roam the North Atlantic.
The company has three sizes of drones and is choosing its 23-foot Explorer model for this mission.

The drones resemble enormous surfboards with fins and have a 16-foot sail on top that is used as a mast for weather instruments, solar panels and a camera.
It can travel at speeds of three knots on missions lasting up to a year at a time.

The drones are powered by sunlight and wind and wirelessly transmit compressed data back to shore.
Some Saildrones are equipped to monitor populations of sharks and other fish and algae.

The design builds upon the last iteration of the Saildrone Explorer, which was used in Palter’s 2019 study.
During that mission, a strong gust of wind tore the wing from the Saildrone — but that didn’t halt the project.

Saildrone Hurricane Wing Testing

“The wing ripped in half, but the drone continued to operate for about 10 days,” said Miglarese.
“They got more data than they’ve ever gotten before.
After that mission, Richard, [Saildrone’s CEO], redesigned the wing.
Now they are meant specifically for this work.”

The new “hurricane wings” will be added to Saildrones that the National Oceanic and Atmospheric Administration will place in the tropics during hurricane season as part of a later project.

Saildrone’s latest endeavor will investigate more than just dissolved carbon concentration.
The drones will collect weather and water temperature data in a part of the Atlantic largely bereft of weather buoys.
That could prove enormously beneficial in improving the accuracy of weather forecasts.

NOAA’s Climate Prediction Center is predicting a 60% chance that the 2021 Atlantic hurricane season will be above-normal, with 13–20 named storms.

About half of those are expected to become hurricanes, and 3–5 of those are expected to become major hurricanes, Category 3 or higher. 

The European Centre for Medium-range Weather Forecasts, or ECMWF, hosts the most powerful weather model in the world and is often considered the most accurate.
It hopes that data provided by the Saildrones will improve forecasts made for Europe.

“We will ingest some of the data from the Saildrones, but not all,” Philip Browne, a data scientist at the ECMWF, wrote in an email.
“In particular we will use the surface pressure data operationally, and that will go straight into the weather forecasts we produce.”

That could bring model improvements as soon as the data starts flowing.

Ocean current data from the Gulf Stream will be vetted and used only internally at first because scientists at the ECMWF need to make sure the data is processed and handled by computers correctly.

“The many other sensors and observation types carried by the Saildrones have different routes into the system,” Browne said.
“For example, the sea surface temperature measurements will end up in our forecasts.”

He explained that sea surface data is first taken in by the United Kingdom Met Office, which produces a global sea surface temperature analysis, which is fed into the ECMWF model.
“The data should be available for all weather centres to use if they can,” Browne wrote.

In the meantime, Miglarese said she is excited for what’s ahead for Saildrone and is looking to the rollout of its biggest model yet — the Saildrone Surveyor.
“We just launched a 72-foot drone that does bathymetric measurements,” she said.
Bathymetry describes the shape, depth and topographic features of the sea floor.
“It’s a big vessel. It’s pushing a lot of power.”

Links :

• CNET : Autonomous Saildrones are the newest weapon in fighting climate change
• SailDrone : Sailing into the Eye of the Storm
• WashingtonPost : Scientists hope to steer robotic surfboards into hurricanes 
• ECMWF : Saildrone to help ECMWF understand the Gulf Stream

In sailing, women are taking more than a seat

The all-female Team SCA, of which the British sailor Sam Davies was the skipper, during the Cape Town Practice Race of the Volvo Ocean Race 2014-15.

Credit... Ainhoa Sanchez/Volvo Ocean Race, via Getty Images

From NYTimes by David Schmidt

They have waited years to earn respect, but now they are winning races and skippering and owning boats.

Competitive sailing has long been an old-boys’ club, yet over the past several decades, women have not only been joining the sport, they have also sometimes been taking charge of it.
They have become senior executives of sailing organizations and yacht clubs, and skippers and owners of boats.

For the first time, in 2018, a female skipper won an around-the-world race, one of the most grueling events in any sport, and five all-women’s teams have completed the round-the-world Volvo Ocean Race (now called just the Ocean Race).
The last American sailor to win an Olympic gold medal was a woman, in 2008, and women have also hoisted the America’s Cup.

Dawn Riley did that in 1992, and she now leads one of the pre-eminent high-performance sailing training centers in the United States.
Cory Sertl is president of US Sailing, the national governing body, and vice president of World Sailing, the international governing body.
And Lindsey Duda Coe was one of the winners of the Chicago Yacht Club’s 2019 Race to Mackinac on the boat she owns.

“Women athletes have been participating in Olympic sailing since 1988,” Sertl said.
“So, there are now more women who have experienced sailing at the highest level, and a number of these women have been drawn into being officials and leaders in the sport.”

Anna Tunnicliffe Tobias of the United States, competing at the 2008 Olympic Games in Beijing, where she won a gold medal.Credit...

Clive Mason/Getty Images

Pamela Healy, a bronze medalist at the 1992 Summer Olympics, said having female leaders was vital.

“There was a Harvard Business Review study on boardroom dynamics that showed that corporations are more successful when they have at least three women voting members on their board of directors,” she said.
“Women add a diverse perspective that is invaluable to decision making and problem solving.”

In addition to winning countless races, Healy has served on the boards of directors of the St.
Francis Yacht Club and the San Francisco Yacht Club and is the president of the St.
Francis Sailing Foundation.
“I feel respected,” she said.
“I don’t feel that I’m a token.”

Still, she sees opportunities for improvement.
“It’s important to see photos of women in blazers on the wall, so women feel represented,” Healy said, referring to yacht-club leadership.
“And we need to improve boat ownership. That will equate to true equality.”

Some gender accomplishments have been hard-won.
Riley said she once discovered that a male crew member with similar duties and experience was being paid twice as much as she was.

“I’m pretty happy with where I’ve gotten,” said Riley, who later served as team captain of the mostly female America’s Cup team­ Mighty Mary.
“But my path was decidedly different than if I was male.”

Sertl, who was a member of the 1988 United States Olympic Sailing Team, said sailing was still evolving.

“I feel really fortunate in the U.S. to have tremendous support from men and women,” she said of her position at US Sailing.
“But World Sailing is different and changing.”

For example, five years ago, Sertl made a motion at a meeting of World Sailing to have gender equity in classes of boats and in the number of medals and athletes at future Olympics.
At that time, there were more sailing events for men than for women.
“Three men in the room objected,” she said.

While women have competed for sailing medals since the 1988 Summer Olympics, and the International Olympic Committee is mandating a push for gender equality, Sertl wants to see more female coaches who can serve as role models for aspiring female Olympic athletes.
“Many female athletes coming up haven’t had a high-performance female sailing coach,” she said

Sam Davies is one of the most accomplished offshore sailors in the world, male or female, and has competed three times in the Vendée Globe, the solo around-the-world race.
Far more people have reached the summit of Mount Everest than have completed the Vendée Globe, which takes about 80 days to finish.

“I think that some of the hardest challenges I face are not because I’m a woman skipper, but because what I do is hard,” said Davies, who has also skippered the all-women’s Team SCA in the 2014-15 fully crewed Volvo Ocean Race.

But she also said that women had a possible advantage in her sport: sponsorships.

“It’s maybe easier if you’re a good woman skipper,” she said of the Vendée Globe.
“Women can bring a good return on investment for a sponsor, because we’re a minority in a male-dominated sport.”

But finding sponsorship and acquiring the right boat are different matters.
Of the 30 boats that were on the starting line of the 2020-21 Vendée Globe, five were skippered by women.
Eight were new designs, all skippered by men.
“What’s missing is a sponsor who will give a boat that’s capable of winning to a female skipper,” Davies said.

The skipper Wendy Tuck, winner of the 2017-18 Clipper Round the World Race.Credit...Miguel Rojo/Agence France-Presse — Getty Images

So far, Wendy Tuck is the only female skipper to have won an around-the-world race.

“When I started skippering, I didn’t realize there wasn’t one,” said Tuck, who won the 2017-18 Clipper Round the World Race.
Unlike the professional crews of the Ocean Race, Clipper crew members pay to race aboard identical boats under the tutelage of experienced skippers like Tuck.
While this may lower the race’s level of competition, it increases the skipper’s leadership challenges.
“My crews varied, but they were roughly 30 to 40 percent women,” Tuck said.
“I’ve been on non-Clipper trips where the men say that they like having females aboard, because it changes the dynamics.”

Although the number of women who are skippers has been growing, they are still outnumbered by men, which can hurt confidence.

“A lot of women still believe that men are more capable than women,” said Kristina Plattner, who is skipper of the TP52 Phoenix 12, which she races on the 52 Super Series circuit.
“But it’s not true, especially for helming a yacht.”

Which is why role models are critical.
“I really hope that other girls can see women out there driving,” said Duda Coe, owner of the Santa Cruz 52 Sin Duda.
She admitted that being a female skipper was sometimes a struggle.
“Even on a boat I own, I’ve been intimidated by guys,” she said.

The gender disparity, she added, is part cultural and part physiological.
“Body size and strength are important,” Duda Coe said, but they are not the whole picture.

Anna Tunnicliffe Tobias after her gold medal victory in the Laser Radial class event in Beijing.

Credit... Clive Mason/Getty Images

Anna Tunnicliffe Tobias, who won the last United States sailing Olympic gold medal, said the importance of those factors depended on the task.

“I’m fairly fit, I think, but I cannot put out the wattage on the winches that some of the guys put out for 10 to 20 minutes, just because I don’t have the weight or height to put behind it,” she said.
“However, there are many other positions that I can do in the back of the boat, like drive, call tactics and navigate.”

Still, Tunnicliffe Tobias, who is also an elite-level CrossFit athlete, acknowledged that Grand Prix sailing is highly competitive.
“At the elite level, there are only so many spots available,” she said.
“I was once told, ‘If you want a spot on the boat, earn it’. It resonated well with me.”

More women are getting the opportunity to earn their spots aboard the most sophisticated boats because of efforts like SailGP’s mandate that teams have at least one female sailor.
Other Grand Prix events, such as the Ocean Race, offer incentives, like having a larger crew, to teams that race with female sailors.

So while women have made great strides in sailing, Riley isn’t content.
“When you shatter the glass ceiling, it’s not the first woman, it’s the third,” she said.
“That’s when you start to get equity.”

Maritime infographic: The fall of the mighty Titanic

 From MaritimeCyprus

The above infographic represents the best estimations science and history can currently make as to what happened in the moments immediately before and after the Titanic disappeared beneath the surface.

 

Links :

• Safety4Sea : Remembering Titanic: The tragedy behind SOLAS 

Ocean crossing in an outboard boat: The Al Grover story

Al Grover and his sons squared off against a monstrous hurricane, a near-drowning, fuel-issues and exhaustion on their way to earning a Guinness World Record for being the first outboard-powered boat to cross the Atlantic.

Man and machine vs. the ocean. Join us as we visit Grover in his home in Freeport, NY to hear his incredible story firsthand.