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Suit up with nanofiber for protection against explosions and high temperatures

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Where explosions are concerned you might expect to see some army research and you would be right. A June 29, 2020 news item on ScienceDaily breaks the news,

Since World War I, the vast majority of American combat casualties has come not from gunshot wounds but from explosions. Today, most soldiers wear a heavy, bullet-proof vest to protect their torso but much of their body remains exposed to the indiscriminate aim of explosive fragments and shrapnel.

Designing equipment to protect extremities against the extreme temperatures and deadly projectiles that accompany an explosion has been difficult because of a fundamental property of materials. Materials that are strong enough to protect against ballistic threats can’t protect against extreme temperatures and vice versa. As a result, much of today’s protective equipment is composed of multiple layers of different materials, leading to bulky, heavy gear that, if worn on the arms and legs, would severely limit a soldier’s mobility.

Now, Harvard University researchers, in collaboration with the U.S. Army Combat Capabilities Development Command Soldier Center (CCDC SC) and West Point, have developed a lightweight, multifunctional nanofiber material that can protect wearers from both extreme temperatures and ballistic threats.

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A June 29, 2020 Harvard University news release (also on EurekAlert) by Leah Burrows, which originated the news item, expands on the theme,

“When I was in combat in Afghanistan, I saw firsthand how body armor could save lives,” said senior author Kit Parker, the Tarr Family Professor of Bioengineering and Applied Physics at the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) and a lieutenant colonel in the United States Army Reserve. “I also saw how heavy body armor could limit mobility. As soldiers on the battlefield, the three primary tasks are to move, shoot, and communicate. If you limit one of those, you decrease survivability and you endanger mission success.”

“Our goal was to design a multifunctional material that could protect someone working in an extreme environment, such as an astronaut, firefighter or soldier, from the many different threats they face,” said Grant M. Gonzalez, a postdoctoral fellow at SEAS and first author of the paper.

In order to achieve this practical goal, the researchers needed to explore the tradeoff between mechanical protection and thermal insulation, properties rooted in a material’s molecular structure and orientation.

Materials with strong mechanical protection, such as metals and ceramics, have a highly ordered and aligned molecular structure. This structure allows them to withstand and distribute the energy of a direct blow. Insulating materials, on the other hand, have a much less ordered structure, which prevents the transmission of heat through the material.

Kevlar and Twaron are commercial products used extensively in protective equipment and can provide either ballistic or thermal protection, depending on how they are manufactured. Woven Kevlar, for example, has a highly aligned crystalline structure and is used in protective bulletproof vests. Porous Kevlar aerogels, on the other hand, have been shown to have high thermal insulation.

“Our idea was to use this Kevlar polymer to combine the woven, ordered structure of fibers with the porosity of aerogels to make long, continuous fibers with porous spacing in between,” said Gonzalez. “In this system, the long fibers could resist a mechanical impact while the pores would limit heat diffusion.”

The research team used immersion Rotary Jet-Spinning (iRJS), a technique developed by Parker’s Disease Biophysics Group, to manufacture the fibers. In this technique, a liquid polymer solution is loaded into a reservoir and pushed out through a tiny opening by centrifugal force as the device spins. When the polymer solution shoots out of the reservoir, it first passes through an area of open air, where the polymers elongate and the chains align. Then the solution hits a liquid bath that removes the solvent and precipitates the polymers to form solid fibers. Since the bath is also spinning — like water in a salad spinner — the nanofibers follow the stream of the vortex and wrap around a rotating collector at the base of the device.

By tuning the viscosity of the liquid polymer solution, the researchers were able to spin long, aligned nanofibers into porous sheets — providing enough order to protect against projectiles but enough disorder to protect against heat. In about 10 minutes, the team could spin sheets about 10 by 30 centimeters in size.

To test the sheets, the Harvard team turned to their collaborators to perform ballistic tests. Researchers at CCDC SC in Natick, Massachusetts simulated shrapnel impact by shooting large, BB-like projectiles at the sample. The team performed tests by sandwiching the nanofiber sheets between sheets of woven Twaron. They observed little difference in protection between a stack of all woven Twaron sheets and a combined stack of woven Twaron and spun nanofibers.

“The capabilities of the CCDC SC allow us to quantify the successes of our fibers from the perspective of protective equipment for warfighters, specifically,” said Gonzalez.

“Academic collaborations, especially those with distinguished local universities such as Harvard, provide CCDC SC the opportunity to leverage cutting-edge expertise and facilities to augment our own R&D capabilities,” said Kathleen Swana, a researcher at CCDC SC and one of the paper’s authors. “CCDC SC, in return, provides valuable scientific and soldier-centric expertise and testing capabilities to help drive the research forward.”

In testing for thermal protection, the researchers found that the nanofibers provided 20 times the heat insulation capability of commercial Twaron and Kevlar.

“While there are improvements that could be made, we have pushed the boundaries of what’s possible and started moving the field towards this kind of multifunctional material,” said Gonzalez.

“We’ve shown that you can develop highly protective textiles for people that work in harm’s way,” said Parker. “Our challenge now is to evolve the scientific advances to innovative products for my brothers and sisters in arms.”

Harvard’s Office of Technology Development has filed a patent application for the technology and is actively seeking commercialization opportunities.

Here’s a link to and a citation for the paper,

para-Aramid Fiber Sheets for Simultaneous Mechanical and Thermal Protection in Extreme Environments by Grant M. Gonzalez, Janet Ward, John Song, Kathleen Swana, Stephen A. Fossey, Jesse L. Palmer, Felita W. Zhang, Veronica M. Lucian, Luca Cera, John F. Zimmerman, F. John Burpo, Kevin Kit Parker. Matter DOI: https://doi.org/10.1016/j.matt.2020.06.001 Published:June 29, 2020

This paper is behind a paywall.

While this is the first time I’ve featured clothing/armour that’s protective against explosions I have on at least two occasions featured bulletproof clothing in a Canadian context. A November 4, 2013 posting had a story about a Toronto-based tailoring establishment, Garrison Bespoke, that was going to publicly test a bulletproof business suit. Should you be interested, it is possible to order the suit here. There’s also a February 11, 2020 posting announcing research into “Comfortable, bulletproof clothing for Canada’s Department of National Defence.”

Masdar Institute and rainmaking

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Water security, of course, is a key issue and of particular concern in many parts of the world including the Middle East. (In the Pacific Northwest, an area described as a temperate rain forest, there tends to be less awareness but even we are sometimes forced to ration water.) According to a July 5, 2017 posting by Bhok Thompson (on the Green Prophet website) scientists at the Masdar Institute of Science and Technology (in Abu Dhabi, United Arab Emirates [UA]E) have applied for a patent on a new technique for rainmaking,

Umbrella sales in the UAE may soon see a surge in pricing. Researchers at the Masdar Institute have filed for a provisional patent with the United States Patent and Trademark Office for their discovery – and innovative cloud seeding material that moves them closer to their goal of producing rain on demand. It appears to be a more practical approach than building artificial mountains.

Dr. Linda Zou is leading the project. A professor of chemical and environmental engineering, she is one of the first scientists to explore nanotechnology to enhance a cloud seeding material’s ability to produce rain. By filing a patent, the team is paving a way to commercialize their discovery, and aligning with Masdar Institute’s aim to position the UAE as a world leader in science and tech, specifically in the realm of environmental sustainability.

A January 31, 2017 posting by Erica Solomon for the Masdar Institute reveals more about the project,

The Masdar Institute research team that was one of the inaugural recipients of the US$ 5 million grant from the UAE Research Program for Rain Enhancement Science last year has made significant progress in their work as evidenced by the filing a provisional patent with the United States Patent and Trademark Office (USPTO).

By filing a patent on their innovative cloud seeding material, the research team is bringing the material in the pathway for commercialization, thereby supporting Masdar Institute’s goal of bolstering the United Arab Emirates’ local intellectual property, which is a key measure of the country’s innovation drive. It also signifies a milestone towards achieving greater water security in the UAE, as rainfall enhancement via cloud seeding can potentially increase rainfall between 10% to 30%, helping to refresh groundwater reserves, boost agricultural production, and reduce the country’s heavy reliance on freshwater produced by energy-intensive seawater desalination.

Masdar Institute Professor of Chemical and Environmental Engineering, Dr. Linda Zou, is the principal investigator of this research project, and one of the first scientists in the world to explore the use of nanotechnology to enhance a cloud seeding material’s ability to produce rain.
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“Using nanotechnology to accelerate water droplet formation on a typical cloud seeding material has never been researched before. It is a new approach that could revolutionize the development of cloud seeding materials and make them significantly more efficient and effective,” Dr. Zou remarked.

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Conventional cloud seeding materials are small particles such as pure salt crystals, dry ice and silver iodide. These tiny particles, which are a few microns (one-thousandth of a millimeter) in size, act as the core around which water condenses in the clouds, stimulating water droplet growth. Once the air in the cloud reaches a certain level of saturation, it can no longer hold in that moisture, and rain falls. Cloud seeding essentially mimics what naturally occurs in clouds, but enhances the process by adding particles that can stimulate and accelerate the condensation process.

Dr. Zou and her collaborators, Dr. Mustapha Jouiad, Principal Research Scientist in Mechanical and Materials Engineering Department, postdoctoral researcher Dr. Nabil El Hadri and PhD student Haoran Liang, explored ways to improve the process of condensation on a pure salt crystal by layering it with a thin coating of titanium dioxide.

The extremely thin coating measures around 50 nanometers, which is more than one thousand times thinner than a human hair. Despite the coating’s miniscule size, the titanium dioxide’s effect on the salt’s condensation efficiency is significant. Titanium dioxide is a hydrophilic photocatalyst, which means that when in contact with water vapor in the cloud, it helps to initiate and sustain the water vapor adsorption and condensation on the nanoparticle’s surface. This important property of the cloud seeding material speeds up the formation of large water droplets for rainfall.

Dr. Zou’s team found that the titanium dioxide coating improved the salt’s ability to adsorb and condense water vapor over 100 times compared to a pure salt crystal. Such an increase in condensation efficiency could improve a cloud’s ability to produce more precipitation, making rain enhancement operations more efficient and effective. The research will now move to the next stage of simulated cloud and field testing in the future.

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Dr. Zou’s research grant covers two more years of research. During this time, her team will continue to study different design concepts and structures for cloud seeding materials inspired by nanotechnology.

To give you a sense of the urgent need for these technologies, here’s the title from my Aug. 24, 2015 posting, The Gaza is running out of water by 2016 if the United Nations predictions are correct. I’ve not come across any updates on the situation in the Gaza Strip but both Israel and Palestine have recently signed a deal concerning water. Dalia Hatuqa’s August 2017 feature on the water deal for Al Jazeera is critical primarily of Israel (as might be expected) but there are one or two subtle criticisms of Palestine too,

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Critics have also warned that the plan does not address Israeli restrictions on Palestinian access to water and the development of infrastructure needed to address the water crisis in the occupied West Bank.

Palestinians in the West Bank consume only 70 litres of water per capita per day, well below what the World Health Organization recommends as a minimum (100).

In the most vulnerable communities in Area C – those not connected to the water network – that number further drops to 20, according to EWASH, a coalition of Palestinian and international organisations working on water and sanitation in the Palestinian territories.

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The recent bilateral agreement, which does not increase the Palestinians’ quota of water in the Jordan River, makes an untenable situation permanent and guarantees Israel a lion’s share of its water, thus reinforcing the status quo, Buttu [Diana Buttu, a former adviser to the Palestinian negotiating team] said.

“They have moved away from the idea that water is a shared resource and instead adopted the approach that Israel controls and allocates water to Palestinians,” she added. “Israel has been selling water to Palestinians for a long time, but this is enshrining it even further by saying that this is the way to alleviate the water problem.”

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Israeli officials say that water problems in the territories could have been addressed had the Palestinians attended the meetings of the joint committee. Palestinians attribute their refusal to conditions set by their counterparts, namely that they must support Israeli settlement water projects for any Palestinian water improvements to be approved.

According to Israeli foreign ministry spokesman Emmanuel Nahshon, “There are many things to be done together to upgrade the water infrastructure in the PA. We are talking about old, leaking pipes, and a more rational use of water.” He also pointed to the illegal tapping into pipes, which he maintained Palestinians did because they did not want to pay for water. “This is something we’ve been wanting to do over the years, and the new water agreement is one of the ways to deal with that. The new agreement … is not only about water quotas; it’s also about more coherent and better use of water, in order to address the needs of the Palestinians.”

But water specialists say that the root cause of the problem is not illegal activity, but the unavailability of water resources to Palestinians and the mismanagement and diversion of the Jordan River.

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Access to water is gong to be of increasing urgency should temperatures continue to rise as they have. In many parts of the world, potable water is not easy to find and if temperatures continue to rise areas that did have some water security will lose it and the potential for conflict rises hugely. Palestine and Israel may be a harbinger of what’s to come. As for the commodification of water, I have trouble accepting it; I think everyone has a right to water.

The ultimate natural sunscreen

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For those of us in the northern hemisphere, sunscreen season is on the horizon. While the “ultimate natural sunscreen” researchers from the University of California at San Diego (UCSD) have developed is a long way from the marketplace, this is encouraging news (from a May 17, 2017 news item on Nanowerk),

Chemists, materials scientists and nanoengineers at UC San Diego have created what may be the ultimate natural sunscreen.

In a paper published in the American Chemical Society journal ACS Central Science, they report the development of nanoparticles that mimic the behavior of natural melanosomes, melanin-producing cell structures that protect our skin, eyes and other tissues from the harmful effects of ultraviolet radiation.

“Basically, we succeeded in making a synthetic version of the nanoparticles that our skin uses to produce and store melanin and demonstrated in experiments in skin cells that they mimic the behavior of natural melanosomes,” said Nathan Gianneschi, a professor of chemistry and biochemistry, materials science and engineering and nanoengineering at UC San Diego, who headed the team of researchers. The achievement has practical applications.

A May 17, 2017 UCSD news release, which originated the news item, delves into the research,

“Defects in melanin production in humans can cause diseases such as vitiligo and albinism that lack effective treatments,” Gianneschi added.

Vitiligo develops when the immune system wrongly attempts to clear normal melanocytes from the skin, effectively stopping the production of melanocytes. Albinism is due to genetic defects that lead to either the absence or a chemical defect in tyrosinase, a copper-containing enzyme involved in the production of melanin. Both of these diseases lack effective treatments and result in a significant risk of skin cancer for patients.

“The widespread prevalence of these melanin-related diseases and an increasing interest in the performance of various polymeric materials related to melanin prompted us to look for novel synthetic routes for preparing melanin-like materials,” Gianneschi said.

UC San Diego Ultimate natural sunscreenThe scientists found that the synthetic nanoparticles were taken up in tissue culture by keratinocytes, the predominant cell type found in the epidermis, the outer layer of skin. Photo by Yuran Huang and Ying Jones/UC San Diego

Melanin particles are produced naturally in many different sizes and shapes by animals—for iridescent feathers in birds or the pigmented eyes and skin of some reptiles. But scientists have discovered that extracting melanins from natural sources is a difficult and potentially more complex process than producing them synthetically.

Gianneschi and his team discovered two years ago that synthetic melanin-like nanoparticles could be developed in a precisely controllable manner to mimic the performance of natural melanins used in bird feathers.

“We hypothesized that synthetic melanin-like nanoparticles would mimic naturally occurring melanosomes and be taken up by keratinocytes, the predominant cell type found in the epidermis, the outer layer of skin,” said Gianneschi.

In healthy humans, melanin is delivered to keratinocytes in the skin after being excreted as melanosomes from melanocytes.

The UC San Diego scientists prepared melanin-like nanoparticles through the spontaneous oxidation of dopamine—developing biocompatible, synthetic analogues of naturally occurring melanosomes. Then they studied their update, transport, distribution and ultraviolet radiation-protective capabilities in human keratinocytes in tissue culture.

The researchers found that these synthetic nanoparticles were not only taken up and distributed normally, like natural melanosomes, within the keratinocytes, they protected the skin cells from DNA damage due to ultraviolet radiation.

“Considering limitations in the treatment of melanin-defective related diseases and the biocompatibility of these synthetic melanin-like nanoparticles in terms of uptake and degradation, these systems have potential as artificial melanosomes for the development of novel therapies, possibly supplementing the biological functions of natural melanins,” the researchers said in their paper.

The other co-authors of the study were Yuran Huang and Ziying Hu of UC San Diego’s Materials Science and Engineering Program, Yiwen Li and Maria Proetto of the Department of Chemistry and Biochemistry; Xiujun Yue of the Department of Nanoengineering; and Ying Jones of the Electron Microscopy Core Facility.

The UC San Diego Office of Innovation and Commercialization has filed a patent application on the use of polydopamine-based artificial melanins as an intracellular UV-shield. Companies interested in commercializing this invention should contact Skip Cynar at invent@ucsd.edu

Here’s a link to and a citation fro the paper,

Mimicking Melanosomes: Polydopamine Nanoparticles as Artificial Microparasols by
Yuran Huang, Yiwen Li, Ziying Hu, Xiujun Yue, Maria T. Proetto, Ying Jones, and Nathan C. Gianneschi. ACS Cent. Sci., Article ASAP DOI: 10.1021/acscentsci.6b00230 Publication Date (Web): May 18, 2017

Copyright © 2017 American Chemical Society

This is an open access paper,

Detonating (exploding) your way to graphene

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Physicists at Kansas State University use controlled detonation to make graphene according to a Jan. 25, 2017 news item on Nanowerk (Note: A link has been removed),

Forget chemicals, catalysts and expensive machinery — a Kansas State University team of physicists has discovered a way to mass-produce graphene with three ingredients: hydrocarbon gas, oxygen and a spark plug.

Their method is simple: Fill a chamber with acetylene or ethylene gas and oxygen. Use a vehicle spark plug to create a contained detonation. Collect the graphene that forms afterward.

Chris Sorensen, Cortelyou-Rust university distinguished professor of physics, is the lead inventor of the recently issued patent, “Process for high-yield production of graphene via detonation of carbon-containing material”. Other Kansas State University researchers involved include Arjun Nepal, postdoctoral researcher and instructor of physics, and Gajendra Prasad Singh, former visiting scientist.

For further reading here’s the Jan. 25, 2017 Kansas State University news release, which originated the news item,

“We have discovered a viable process to make graphene,” Sorensen said. “Our process has many positive properties, from the economic feasibility, the possibility for large-scale production and the lack of nasty chemicals. What might be the best property of all is that the energy required to make a gram of graphene through our process is much less than other processes because all it takes is a single spark.”

Graphene is a single atom-thick sheet of hexagonally coordinated carbon atoms, which makes it the world’s thinnest material. Since graphene was isolated in 2004, scientists have found it has valuable physical and electronic properties with many possible applications, such as more efficient rechargeable batteries or better electronics.

For Sorensen’s research team, the serendipitous path to creating graphene started when they were developing and patenting carbon soot aerosol gels. They created the gels by filling a 17-liter aluminum chamber with acetylene gas and oxygen. Using a spark plug, they created a detonation in the chamber. The soot from the detonation formed aerosol gels that looked like “black angel food cake,” Sorensen said.

But after further analysis, the researchers found that the aerosol gel was more than lookalike dark angel food cake — it was graphene.

“We made graphene by serendipity,” Sorensen said. “We didn’t plan on making graphene. We planned on making the aerosol gel and we got lucky.”

But unlike other methods of creating graphene, Sorensen’s method is simple, efficient, low-cost and scalable for industry.

Other methods of creating graphene involve “cooking” the mineral graphite with chemicals — such as sulfuric acid, sodium nitrate, potassium permanganate or hydrazine — for a long time at precisely prescribed temperatures. Additional methods involve heating hydrocarbons to 1,000 degrees Celsius in the presence of catalysts.

Such methods are energy intensive — and even dangerous — and have low yield, while Sorensen and his team’s method makes larger quantities with minimal energy and no dangerous chemicals.

“The real charm of our experiment is that we can produce graphene in the quantity of grams rather than milligrams,” Nepal said.

Now the research team — including Justin Wright, doctoral student in physics, Camp Hill, Pennsylvania — is working to improve the quality of the graphene and scale the laboratory process to an industrial level. They are upgrading some of the equipment to make it easier to get graphene from the chamber seconds — rather than minutes — after the detonation. Accessing the graphene more quickly could improve the quality of the material, Sorensen said.

The patent was issued to the Kansas State University Research Foundation, a nonprofit corporation responsible for managing technology transfer activities at the university.

I wish they’d filmed one of their graphene explosions even if it meant that all we’d get is the sight of a canister and the sound of a boom. Still, they did show a brief spark from the spark plug.