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Bogeyman 

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Scientists Discovered A 2D Material That Is 10X Tougher Than Graphene​

Hexagonal boron nitride (h-BN) is officially the iron man of two-dimensional materials. It’s so resistant to cracking that it defies a century-old fundamental theoretical description of fracture mechanics that engineers still use to predict and measure toughness.

h-BN has remarkably similar physical properties to graphene, but it’s so resistant to cracking that it significantly surpasses graphene in toughness.

Jun Lou, a materials scientist at Rice University and co-corresponding author of the study, said:

What we observed in this material is remarkable. Nobody expected to see this in 2D materials. That’s why it’s so exciting.
Both h-BN and graphene consist of hexagonal lattices of atoms. However, graphene’s hexagons are all carbon atoms, while h-BN’s are three nitrogen and three boron atoms. Here’s where things get interesting. It’s expected that graphene would be much more robust than h-BN because carbon-carbon bonds are among the strongest in nature.

And it essentially is since both materials have nearly equal values for elasticity and strength – but graphene’s values are slightly higher. Graphene has a strength of about 1.0 terapascals for elasticity and 130 gigapascals for strength; h-BN’s values are 0.8 terapascals and 100 gigapascals, respectively.

But graphene’s performance can go from extraordinary to mediocre if even a few atoms are out of place. And since no material is defect-free in the real world, the chances of this are higher than not. That’s why graphene has a low resistance to cracks, meaning it very brittle.


Lou explained:

We measured the fracture toughness of graphene seven years ago, and it’s not very resistant to fracture. If you have a crack in the lattice, a small load will break that material.
Meanwhile, when the researchers tested h-BN’s fracture resistance, they found it to be ten times higher than that of graphene’s. Its behavior in fracture tests was so unforeseen that it defied description with Griffith’s formula.

Huajian Gao, a mechanician at Nanyang Technological University in Singapore, said:

What makes this work so exciting is that it unveils an intrinsic toughening mechanism in a supposedly perfectly brittle material. Even Griffith couldn’t foresee such drastically different fracture behaviors in two brittle materials with similar atomic structures.
It took Lou’s lab over 1,000 hours of experiments to show precisely how h-BN behaved and why.

branching-fracture.jpg

“A scanning electron microscope image shows branched cracks in a single crystal of 2D hexagonal boron nitride (h-BN). Experiments and computational modeling by Rice University and Nanyang Technological University showed h-BN lattice asymmetry allows cracks to follow branching paths, which effectively toughens the 2D material by making it more difficult for cracks to propagate.” Credit: J. Lou/Rice University)


They found that h-BN has a slight asymmetry in its hexagonal structure because of the contrast in stress between the nitrogen and the boron, meaning cracks tend to bifurcate. So, breaks tend to branch and turn. On the other hand, graphene has a symmetrical hexagonal structure, so cracks tend to zig-zag straight through from top to bottom. So, cracks open bonds like a zipper.

Lou said:

Boron and nitrogen are not the same, so even though you have this hexagon, it is not exactly like the carbon hexagon (in graphene) because of this asymmetric arrangement.

If the crack is branched, that means it is turning. If you have this turning crack, it costs additional energy to drive the crack further. So, you’ve effectively toughened your material by making it much harder for the crack to propagate.
Gao added:

The intrinsic lattice asymmetry endows h-BN with a permanent tendency for a moving crack to branch off its path, like a skier who has lost her or his ability to maintain a balanced posture to move straight forward.
This discovery marks h-BN as an ideal candidate material for developing flexible 2D materials for electronics and other applications. And h-BN is also heat resistant, chemically stable. It possesses dielectric properties (allowing it to serve as an insulating layer between and a supporting base for electronic components) – all the properties of a material suitable for electronics.

Lou said:

The niche area for 2D material-based electronics is the flexible device. For this type of configuration, you need to ensure the material itself is mechanically robust when you bend it around. That h-BN is so fracture-resistant is great news for the 2D electronic community because it can use this material as a very effective protective layer.
Potential uses for h-BN include technologies like stick-on electronic tattoos, electronic textiles, and implants.
 

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Using liquid metal to turn motion into electricity, even underwater​


Researchers at North Carolina State University have created a soft and stretchable device that converts movement into electricity and can work in wet environments.

"Mechanical energy—such as the kinetic energy of wind, waves, body movement and vibrations from motors—is abundant," says Michael Dickey, corresponding author of a paper on the work and Camille & Henry Dreyfus Professor of Chemical and Biomolecular Engineering at NC State. "We have created a device that can turn this type of mechanical motion into electricity. And one of its remarkable attributes is that it works perfectly well underwater."

The heart of the energy harvester is a liquid metal alloy of gallium and indium. The alloy is encased in a hydrogel—a soft, elastic polymer swollen with water.

The water in the hydrogel contains dissolved salts called ions. The ions assemble at the surface of the metal, which can induce charge in the metal. Increasing the area of the metal provides more surface to attract charge. This generates electricity, which is captured by a wire attached to the device.

"Since the device is soft, any mechanical motion can cause it to deform, including squishing, stretching and twisting," Dickey says. "This makes it versatile for harvesting mechanical energy. For example, the hydrogel is elastic enough to be stretched to five times its original length."



In experiments, researchers found that deforming the device by only a few millimeters generates a power density of approximately 0.5 mW m-2. This amount of electricity is comparable to several popular classes of energy harvesting technologies.

"However, other technologies don't work well, if at all, in wet environments," Dickey says. "This unique feature may enable applications from biomedical settings to athletic wear to marine environments. Plus, the device is simple to make.

"There is a path to increase the power, so we consider the work we described here a proof-of-concept demonstration."

The researchers already have two related projects under way.

One project is aimed at using the technology to power wearable devices by increasing the harvester's power output. The second project evaluates how this technology could be used to harvest wave power from the ocean.

The paper, "A Soft Variable-Area Electrical-Double-Layer Energy Harvester," is published in the journal Advanced Materials.

 

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Ultrathin self-healing polymers create new, sustainable water-resistant coatings​


Researchers have found a way to make ultrathin surface coatings robust enough to survive scratches and dings. The new material, developed by merging thin-film and self-healing technologies, has an almost endless list of potential applications, including self-cleaning, anti-icing, anti-fogging, anti-bacterial, anti-fouling and enhanced heat exchange coatings, researchers said.

The new study found that the rapid evaporative qualities of a specialized polymer containing a network of dynamic bonds in its backbone help form a water-resistant, self-healing coating of nanoscale thicknesses. The study, led by University of Illinois Urbana-Champaign mechanical science and engineering professor Nenad Miljkovic and materials science and engineering professor Christopher Evans, is published in the journal Nature Communications.

For this study, the Miljkovic group’s primary focus was on boosting the efficiency of steam power plants, which are the biggest producers of electricity globally, by using these types of coatings in their condensers. “The coatings, when applied to the surfaces of the condensers, make them more water-resistant and efficient at forming water droplets, which optimizes heat transfer,” said graduate research assistant Jingcheng Ma, a co-lead author of the study.

When used in steam power plants, thin coatings can run into a multitude of durability problems, the researchers said. Coatings can break down in weeks, sometimes even hours. Such a short lifetime makes the real-world application of the coatings impractical, which has been a foundational challenge in mechanical and materials sciences for about eight decades. Thicker coatings can be more durable, but they reduce heat transfer and erode the associated benefit of the coating.

Previous studies have shown that most ultrathin coatings develop tiny pinhole defects once they cure onto a surface. Steam penetrates through these defects, leading to the gradual delamination of the coating, the researchers said, so their goal was to develop a pinhole-free, water-resistant thin-film and enhance the overall energy efficiency of steam power plants by several percent.

“Self-healing materials can recycle and reprocess themselves,” Evans said. “We found that we can successfully utilize the healing enabled by the dynamic bonds, allowing the coatings to self-repair in response to scratching or to prevent pinholes from growing.”

Called dyn-PDMS, the material can be easily dip-coated onto materials in nanoscale layers on various surfaces like silicon, aluminum, copper or steel.

“One of the reasons we can get such thin layers is because the solvents used in the reaction evaporate very quickly, leaving only the polymer,” Evans said. “Also, once cured, the material repairs itself from scratches very fast – so fast that it is difficult to observe in real time. We do not see this behavior in large, bulk samples of the material – only in the thin-film, and that is a question we are trying to answer now.”

The researchers posit that the ultrathin coatings developed in this study offer a solution for sustainable water-resistant materials and raise open scientific questions within materials science and fluid mechanics that remain unanswered.

The Office of Naval Research, the International Institute for Carbon Neutral Energy Research, the Air Force Office of Scientific Research and the National Science Foundation supported this research.

Miljkovic and Evans are both affiliated with the Materials Research Laboratory. Miljkovic also is affiliated with electrical and computer engineering. Evans also is affiliated with the Beckman Institute for Advanced Science and Technology and chemical and biomolecular engineering.

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Saithan

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The CarbFix method was upscaled at the Hellisheiði geothermal power plant to inject and mineralize the plant’s CO2 and H2S emissions in June 2014. This approach first captures the gases by their dissolution in water, and the resulting gas-charged water is injected into subsurface basalts.

The dissolved CO2 and H2S then react with the basaltic rocks liberating divalent cations, Ca²⁺, Mg²⁺, and Fe²⁺, increasing the fluid pH, and precipitating stable carbonate and sulfide minerals. By the end of 2017, 23,200 metric tons of CO2 and 11,800 metric tons of H2S had been injected to a depth of 750 m into fractured, hydrothermally altered basalts at >250 °C. The in situ fluid composition, as well as saturation indices and predominance diagrams of relevant secondary minerals at the injection and monitoring wells, indicate that sulfide precipitation is not limited by the availability of Fe or by the consumption of Fe by other secondary minerals; Ca release from the reservoir rocks to the fluid phase, however, is potentially the limiting factor for calcite precipitation, although dolomite and thus aqueous Mg may also play a role in the mineralization of the injected carbon.

During the first phase of the CarbFix2 injection (June 2014 to July 2016) over 50% of injected carbon and 76% of sulfur mineralized within four to nine months, but these percentages increased four months after the amount of injected gas was doubled during the second phase of CarbFix2 (July 2016–December 2017) at over 60% of carbon and over 85% of sulfur. The doubling of the gas injection rate decreased the pH of the injection water liberating more cations for gas mineralization. Notably, the injectivity of the injection well has remained stable throughout the study period confirming that the host rock permeability has been essentially unaffected by 3.5 years of mineralization reactions. Lastly, although the mineralization reactions are accelerated by the high temperatures (> 250 °C), this is the upper temperature limit for carbon storage via the mineral carbonation of basalts as higher temperatures leads to potential decarbonation reactions.


Shouldn't we invest in this technology and get some first hand experience and knowledge on it ?

In short it's a method of injecting co2 into water and pump it subsurface to a place with basalt of sorts and such.
 

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Everyone owes it to themselves (if they haven't already) knowing the basics of semiconductor solar technology, given it is going to be a huge increasing part of electricity generation profile in the years to come.

This video does a very good job in laying out the basics:


It reminds me quite a bit of how my dad (who worked in a semiconductor MNC for his career) would fill my head with all this kind of information when I was still kind of young to really grasp it. I have long since overall understood and used the technology myself haha.

For those that would like a bit more expansion on where the improvement in efficiency is broadly headed....it is by use of a larger profile of semiconductor materials (that have different band gaps to silicon and thus able to use more of the incident sunlight emission spectrum when you multi-layer and multi-junction by stacking them up etc...given lot of these materials are not constrained by silicon's "indirect bandgap" which wastes energy by lattice vibration)

A good summary of this can be found here for those interested:


There are of course engineering, design and cost challenges of this approach (you will notice the page is from 2002) and this forms the ongoing research and development of this technology currently.

Some of the recent news on it (multijunction):



10 billion dollar and years of R&D, lets hope it doesn't fail...
 

Zafer

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Nilgiri

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this is a crazy idea, what for now never will happen.

I think its interesting approach. I mean we are talking about small payloads here.....there is lot of money to be saved for sounding rocket lower stage.
 

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What 'phase' of the universe after the Big Bang each megaproject studies/seeks to recreate.

Note: the graphic only shows those programs that the Indian govt. is directly invested in as a partner, there are several other, smaller scale programs across the world that study each of the 'phases' so this is not a definitive list.

VS.JPG


More details regarding each project & the involvement from companies:

 

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A futurist engineer from Yemen and Hashim al-Ghaili developed a project for a flying plane-hotel Sky Cruise. The flying nuclear-powered hotel Sky Cruise is capable of carrying up to 5,000 people. The giant plane will fly without pilots. The artificial intelligence system will be in charge of this, but a human will be able to take control at any time. According to the author's idea, the artificial intelligence-controlled Sky Cruise will take to the skies thanks to 20 nuclear-powered engines. According to the creator, this will solve the issue of carbon dioxide emissions. The liner will not need to land on the ground for maintenance, it will be able to fly for years. Everything necessary for a normal life of people will be delivered by electric aircraft. So far, mankind does not have the opportunity to implement such a project. On the other hand, not so long ago, tourist flights into space were also considered science fiction.

 

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haithem-taha-soe-sign-1-400x300-v1.jpg

Pursuit of ‘Useless’ Knowledge Leads to New Theory of Lift​



Challenging a century-old theory of flight is not an easy journey. In fact, many might consider it a pointless pursuit – especially as millions of people board airplanes without a thought about the aerodynamics that keep them in the air.

However, Haithem Taha, UC Irvine associate professor of mechanical and aerospace engineering, and Cody Gonzalez, mechanical and aerospace engineering graduate student, followed their curiosity into what has been considered “useless” knowledge and discovered a new theory of lift, which fundamentally changes how we understand flight. They have published their work “A Variational Theory of Lift” in the Journal of Fluid Mechanics May 6, 2022, issue.

Taha explained, “This work solves a century-old puzzle in aerodynamics. The way we solved the puzzle is not by a complex microscope, an expensive piece of equipment or an advanced computational tool/algorithm. The intellectual puzzle that lasted over a century is solved by using philosophical principles in classical mechanics that were available to the early pioneers of aviation: [Martin] Kutta, [Nikolai] Zhukovky, [Ludwig] Prandtl, [Theodore] Von Karman among others.”

Currently, the main theory of lift taught in aeronautical engineering schools and found in books on aerodynamics is attributed to German mathematician Martin Kutta, published in 1910, explained Taha. Kutta’s theory is confined to special types of shapes of wing sections: those with a single sharp edge at the rear.

However, Kutta’s theory fails to apply if planes have multiple sharp edges, no sharp edges, a single sharp edge in the front, or even a single rear sharp edge in an unsteady flow. The new theory of lift is generally applicable to all those cases and is derived from first principles in mechanics, in contrast to Kutta’s theory.

The principle used to resolve this problem, the Hertz principle of least curvature, is rarely found in textbooks of classical physics and analytical mechanics. “I spent several years studying the history and philosophy of mechanics, which is deemed by contemporary metrics as ‘useless’ knowledge; no publications could come of it,” said Taha. “Also, the courage of my doctoral student, Cody Gonzalez, to pursue his curiosity in an idea that seemed outdated and obsolete, and the freedom given to him to go in this direction played a great factor. The fact this pursuit of ‘useless’ knowledge solves one of the fundamental technical challenges in aerodynamics that lasted over a century confirms the premise of Abraham Flexner's thesis ‘The Usefulness of Useless Knowledge.’”

Peer reviewers have commended the work. “It is a breakthrough in theoretical aerodynamics. Some chapters in aerodynamics books will be rewritten,” said Saad Ragab, professor of biomedical engineering and mechanics at Virginia Tech.

Taha and Gonzalez are sharing their discovery with students and a wider audience through a video, which helps explain the work in layperson’s terms.


“It is expected that this theory may replace or be taught side by side to Kutta’s in the undergraduate curriculum of aeronautical engineering schools throughout the world,” said Taha. “Here at UCI, as well as my alma mater, Virginia Tech, and other schools, some colleagues will start teaching it next year. It is rare to discover new findings related to the basic concepts taught at the undergraduate level in engineering schools. On the industry level, this theory may help create new shapes for wings in the future.”


 

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Researchers achieve world's first international holographic teleportation​



Holographic teleportation sounds like something out of Star Wars or Star Trek, but instead of the bridge of a flashy interstellar spaceship, a world-first technological achievement took place in a nondescript boardroom on campus at Western recently.

The term holographic teleportation, or holoport, is a combination of hologram and teleport: when a hologram of a person or object is transmitted instantaneously to another location.

On the afternoon of July 27, a small group of students from the Western Institute for Space Exploration (Western Space) gathered to witness and take part in the world's first international holoport demonstration.

"We had the incredible opportunity to demonstrate the first international, two-way holographic teleportation," said project leader Leap Biosystem's co-founder, Dr. Adam Sirek, a faculty member at the Schulich School of Medicine Dentistry, and Western Space.

In April, NASA successfully holoported a doctor on to the International Space Station (ISS), becoming the first "holonaut," but last Thursday's Western Space demonstration was the first time anyone has crossed international borders through holographic teleportation.


"We transported one person from Alabama to London, Ontario, and then each of the students here on the project were able to instantly holoport themselves in holographic form down to Huntsville, Alabama," Sirek said.

He joked about the team crossing the border without having to pay an airfare, but within the quick quip comes a nugget of truth about the vast potential of such technology.

The team, composed largely of undergraduate and medical students, is exploring the way this futuristic technology can be used in the real world. Whether it is for people communicating or providing assistance and medical care to remote areas, even in the ISS, the possibilities are only just beginning to be understood.

Precipice of opportunity

The technology for holographic teleportation comes from hardware developed by Microsoft and software from Aexa Aerospace, headquartered in Houston.

Aexa has partnered with Western and Canadian company Leap Biosystems to explore medical applications for the technology, which led to the demonstration of the first international holographic teleportation.


The technology involves a special camera that creates a holographic image of a subject, which is then sent to the destination of choice. The user on the other end is wearing a device called a hololens, not unlike virtual reality gaming headsets. Through the hololens the individual can see the subject within their environment. If both are wearing a hololens, they can interact in their environments as if they are actually there.

While the novelty of traveling a great distance instantaneously is fascinating, for medical student and project intern Adam Levschuk the possibilities for medical care are most exciting.

"It's like the best of both worlds between medicine and engineering. The applications I'm particularly looking at is facilitating physical exams that a doctor would normally conduct in an examination room."

Although there is still work to be done to make conducting a virtual medical exam over the hololens a reality, Levschuk said he is excited to get the opportunity to explore the possibilities.

He also has the added bragging right of saying he attempted the first virtual handshake across international borders.

"Every time you put it on and you see the hologram appear in front of you, it's still a little bit shocking… I could reach out and virtually shake the person's hand on the other end of the line."

Medical student and project intern Alex Zhou said the implications of the technology could be huge for access to health care in remote locations.

"This is very much the future of health care in terms of accessing remote communities, remote environments, and providing rural health-care access," said Zhou.

Sirek agreed with Zhou, emphasizing the cost of the technology is currently around $5,000 which, when compared to the cost of medivacs or even traveling for exams, leads one to conclude this kind of technology could have the potential for huge cost savings for the health-care system.

"It can impact a number of factors including physician access to these (remote) areas and physician licensing. I think it is going to be a very big game-changer for rural health care."

But with the promise of new technology there are inevitably limitations and hurdles to overcome—and that is where the engineering side of the project comes in.

Jocelyn Whittal, a third-year engineering student at Western, found herself being part of the team after she was encouraged to apply by one of her professors.

"As far as the hololens goes, I'm sort of looking at what biosensors might be really easy and also really helpful to integrate with it," said Whittal.

"So whether that's like monitoring heart rate, oxygen saturation or even looking at haptics."

Haptics is the science and technology of transmitting and understanding information through touch, which with a hologram is currently a hurdle.

While the technology can transport a person's image across borders it can't yet interact with touch, which is a big part of a medical exam.

However, Whittal said she is hoping to get haptics as part of the hololens in the future, and of the hololens itself. "I feel like Iron Man."

Next steps

Sirek is excited about the possibilities for the technology, which are not limited to the grand scope of space or betterment of medical care.

Perhaps one of the most obtainable possibilities of this technology for the general public is its potential to connect people. Virtual meetings are the norm now, but with hololens and holographic teleportation, the physical, three-dimensional experience could become mainstream.

"We look at that again from a space perspective; wouldn't it be nice if you're on a three-month deployment to the space station, and you could come down and sit in the room (at home) for a family dinner."

Sirek said one of the most exciting parts is seeing this new generation of students taking on the challenges of today for a better, more connected world tomorrow.

"We have three undergraduate students taking advanced technology and potentially demonstrating that to leaders and decisions-makers for the future of Canada. Our students are actively involved in pushing the boundary of what novel technology can do."

 

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