Tag Archives: explosives

Fireworks for fuel?

Scientists are attempting to harness the power in fireworks for use as fuel according to a Jan. 18, 2017 news item on Nanowerk,

The world relies heavily on gasoline and other hydrocarbons to power its cars and trucks. In search of an alternative fuel type, some researchers are turning to the stuff of fireworks and explosives: metal powders. And now one team is reporting a method to produce a metal nanopowder fuel with high energy content that is stable in air and doesn’t go boom until ignited.

A Jan. 18, 2017 American Chemical Society (ACS) news release, which originated the news item, expands on the theme,

Hydrocarbon fuels are liquid at room temperature, are simple to store, and their energy can be used easily in cars and trucks. Metal powders, which can contain large amounts of energy, have long been used as a fuel in explosives, propellants and pyrotechnics. It might seem counterintuitive to develop them as a fuel for vehicles, but some researchers have proposed to do just that. A major challenge is that high-energy metal nanopowder fuels tend to be unstable and ignite on contact with air. Albert Epshteyn and colleagues wanted to find a way to harness and control them, producing a fuel with both high energy content and good air stability.

The researchers developed a method using an ultrasound-mediated chemical process to combine the metals titanium, aluminum and boron with a sprinkle of hydrogen in a mixed-metal nanopowder fuel. The resulting material was both more stable and had a higher energy content than the standard nano-aluminum fuels. With an energy density of at least 89 kilojoules/milliliter, which is significantly superior to hydrocarbons’ 33 kilojoules/milliliter, this new titanium-aluminum-boron nanopowder packs a big punch in a small package.

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

Optimization of a High Energy Ti-Al-B Nanopowder Fuel by Albert Epshteyn, Michael Raymond Weismiller, Zachary John Huba, Emily L. Maling, and Adam S. Chaimowitz. Energy Fuels, DOI: 10.1021/acs.energyfuels.6b02321 Publication Date (Web): December 30, 2016

Copyright © 2016 American Chemical Society

This paper is behind a paywall.

Spinach and plant nanobionics

Who knew that spinach leaves could be turned into electronic devices? The answer is: engineers at the Massachusetts Institute of Technology, according to an Oct. 31, 2016 news item on phys.org,

Spinach is no longer just a superfood: By embedding leaves with carbon nanotubes, MIT engineers have transformed spinach plants into sensors that can detect explosives and wirelessly relay that information to a handheld device similar to a smartphone.

This is one of the first demonstrations of engineering electronic systems into plants, an approach that the researchers call “plant nanobionics.”

An Oct. 31, 2016 MIT news release (also on EurekAlert), which originated the news item, describes the research further (Note: Links have been removed),

“The goal of plant nanobionics is to introduce nanoparticles into the plant to give it non-native functions,” says Michael Strano, the Carbon P. Dubbs Professor of Chemical Engineering at MIT and the leader of the research team.

In this case, the plants were designed to detect chemical compounds known as nitroaromatics, which are often used in landmines and other explosives. When one of these chemicals is present in the groundwater sampled naturally by the plant, carbon nanotubes embedded in the plant leaves emit a fluorescent signal that can be read with an infrared camera. The camera can be attached to a small computer similar to a smartphone, which then sends an email to the user.

“This is a novel demonstration of how we have overcome the plant/human communication barrier,” says Strano, who believes plant power could also be harnessed to warn of pollutants and environmental conditions such as drought.

Strano is the senior author of a paper describing the nanobionic plants in the Oct. 31 [2016] issue of Nature Materials. The paper’s lead authors are Min Hao Wong, an MIT graduate student who has started a company called Plantea to further develop this technology, and Juan Pablo Giraldo, a former MIT postdoc who is now an assistant professor at the University of California at Riverside.

Environmental monitoring

Two years ago, in the first demonstration of plant nanobionics, Strano and former MIT postdoc Juan Pablo Giraldo used nanoparticles to enhance plants’ photosynthesis ability and to turn them into sensors for nitric oxide, a pollutant produced by combustion.

Plants are ideally suited for monitoring the environment because they already take in a lot of information from their surroundings, Strano says.

“Plants are very good analytical chemists,” he says. “They have an extensive root network in the soil, are constantly sampling groundwater, and have a way to self-power the transport of that water up into the leaves.”

Strano’s lab has previously developed carbon nanotubes that can be used as sensors to detect a wide range of molecules, including hydrogen peroxide, the explosive TNT, and the nerve gas sarin. When the target molecule binds to a polymer wrapped around the nanotube, it alters the tube’s fluorescence.

In the new study, the researchers embedded sensors for nitroaromatic compounds into the leaves of spinach plants. Using a technique called vascular infusion, which involves applying a solution of nanoparticles to the underside of the leaf, they placed the sensors into a leaf layer known as the mesophyll, which is where most photosynthesis takes place.

They also embedded carbon nanotubes that emit a constant fluorescent signal that serves as a reference. This allows the researchers to compare the two fluorescent signals, making it easier to determine if the explosive sensor has detected anything. If there are any explosive molecules in the groundwater, it takes about 10 minutes for the plant to draw them up into the leaves, where they encounter the detector.

To read the signal, the researchers shine a laser onto the leaf, prompting the nanotubes in the leaf to emit near-infrared fluorescent light. This can be detected with a small infrared camera connected to a Raspberry Pi, a $35 credit-card-sized computer similar to the computer inside a smartphone. The signal could also be detected with a smartphone by removing the infrared filter that most camera phones have, the researchers say.

“This setup could be replaced by a cell phone and the right kind of camera,” Strano says. “It’s just the infrared filter that would stop you from using your cell phone.”

Using this setup, the researchers can pick up a signal from about 1 meter away from the plant, and they are now working on increasing that distance.

Michael McAlpine, an associate professor of mechanical engineering at the University of Minnesota, says this approach holds great potential for engineering not only sensors but many other kinds of bionic plants that might receive radio signals or change color.

“When you have manmade materials infiltrated into a living organism, you can have plants do things that plants don’t ordinarily do,” says McAlpine, who was not involved in the research. “Once you start to think of living organisms like plants as biomaterials that can be combined with electronic materials, this is all possible.”

“A wealth of information”

In the 2014 plant nanobionics study, Strano’s lab worked with a common laboratory plant known as Arabidopsis thaliana. However, the researchers wanted to use common spinach plants for the latest study, to demonstrate the versatility of this technique. “You can apply these techniques with any living plant,” Strano says.

So far, the researchers have also engineered spinach plants that can detect dopamine, which influences plant root growth, and they are now working on additional sensors, including some that track the chemicals plants use to convey information within their own tissues.

“Plants are very environmentally responsive,” Strano says. “They know that there is going to be a drought long before we do. They can detect small changes in the properties of soil and water potential. If we tap into those chemical signaling pathways, there is a wealth of information to access.”

These sensors could also help botanists learn more about the inner workings of plants, monitor plant health, and maximize the yield of rare compounds synthesized by plants such as the Madagascar periwinkle, which produces drugs used to treat cancer.

“These sensors give real-time information from the plant. It is almost like having the plant talk to us about the environment they are in,” Wong says. “In the case of precision agriculture, having such information can directly affect yield and margins.”

Once getting over the excitement, questions spring to mind. How could this be implemented? Is somebody  going to plant a field of spinach and then embed the leaves so they can detect landmines? How will anyone know where to plant the spinach? And on a different track, is this spinach edible? I suspect that if spinach can be successfully used as a sensor, it might not be for explosives but for pollution as the researchers suggest.

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

Nitroaromatic detection and infrared communication from wild-type plants using plant nanobionics by Min Hao Wong, Juan P. Giraldo, Seon-Yeong Kwak, Volodymyr B. Koman, Rosalie Sinclair, Tedrick Thomas Salim Lew, Gili Bisker, Pingwei Liu, & Michael S. Strano. Nature Materials (2016) doi:10.1038/nmat4771 Published online 31 October 2016

This paper is behind a paywall.

The last posting here which featured Strano’s research is in an Aug. 25, 2015 piece about carbon nanotubes and medical sensors.

US Army offers course on nanotechnology

As you might expect, the US Army course on nanotechnology stresses the importance of nanotechnology for the military, according to a June 16, 2016 news item on Nanowerk,

If there is one lesson to glean from Picatinny Arsenal’s new course in nanomaterials, it’s this: never underestimate the power of small.

Nanotechnology is the study of manipulating matter on an atomic, molecular, or supermolecular scale. The end result can be found in our everyday products, such as stained glass [This is a reference to the red glass found in churches from the Middle Ages. More about this later in the posting], sunscreen, cellphones, and pharmaceutical products.

Other examples are in U.S. Army items such as vehicle armor, Soldier uniforms, power sources, and weaponry. All living things also can be considered united forms of nanotechnology produced by the forces of nature.

“People tend to think that nanotechnology is all about these little robots roaming around, fixing the environment or repairing damage to your body, and for many reasons that’s just unrealistic,” said Rajen Patel, a senior engineer within the Energetics and Warheads Manufacturing Technology Division, or EWMTD.

The division is part of the U.S. Army Armament Research, Development and Engineering Center or ARDEC.

A June 15, 2016 ARDEC news release by Cassandra Mainiero, which originated the news item, expands on the theme,

“For me, nanotechnology means getting materials to have these properties that you wouldn’t expect them to have.” [Patel]

The subject can be separated into multiple types (nanomedicine, nanomachines, nanoelectronics, nanocomposites, nanophotonics and more), which can benefit areas, such as communications, medicine, environment remediation, and manufacturing.

Nanomaterials are defined as materials that have at least one dimension in the 1-100 nm range (there are 25,400,000 nanometers in one inch.) To provide some size perspective: comparing a nanometer to a meter is like comparing a soccer ball to the earth.

Picatinny’s nanomaterials class focuses on nanomaterials’ distinguishing qualities, such as their optical, electronic, thermal and mechanical properties–and teaches how manipulating them in a weapon can benefit the warfighter [soldier].

While you could learn similar information at a college course, Patel argues that Picatinny’s nanomaterial class is nothing like a university class.

This is because Picatinny’s nanomaterials class focuses on applied, rather than theoretical nanotechnology, using the arsenal as its main source of examples.

“We talk about things like what kind of properties you get, how to make materials, places you might expect to see nanotechnology within the Army,” explained Patel.

The class is taught at the Armament University. Each class lasts three days. The last one was held in February.

Each class includes approximately 25 students and provides an overview of nanotechnology, covering topics, such as its history, early pioneers in the field, and everyday items that rely on nanotechnology.

Additionally, the course covers how those same concepts apply at Picatinny (for electronics, sensors, energetics, robotics, insensitive munitions, and more) and the major difficulties with experimenting and manufacturing nanotechnology.

Moreover, the class involves guest talks from Picatinny engineers and scientists, such as Dan Kaplan, Christopher Haines, and Venkataraman Swaminathan as well as tours of Picatinny facilities like the Nanotechnology Center and the Explosives Research Laboratory.

It also includes lectures from guest speakers, such as Gordon Thomas from the New Jersey Institute of Technology (NJIT), who spoke about nanomaterials and diabetes research.

A CLASSROOM COINCIDENCE

Relatively new, the nanomaterials class launched in January 2015. It was pioneered by Patel after he attended an instructional course on teaching at the Armament University, where he met Erin Williams, a technical training analyst at the university.

“At the Armament University, we’re always trying to think of, ‘What new areas of interest should we offer to help our workforce? What forward reaching technologies are needed?’ One topic that came up was nanotechnology,” said Williams about how the nanomaterials class originated.

“I started to do research on the subject, how it might be geared toward Picatinny, and trying to think of ways to organize the class. Then, I enrolled in the instructional course on teaching, where I just so happen to be sitting across from Dr. Rajen Patel, who not only knew about nanotechnology, but taught a few seminars at NJIT, where he did his doctorate,” explained Williams. “I couldn’t believe the coincidence! So, I asked him if he would be interested in teaching a class and he said ‘Yes!'”

“After the first [nanomaterials] class, one of the students came up to me and said ‘This was the best course I’ve ever been to on this arsenal,'” added Williams. “…This is really how Picatinny shines as a team: when you meet people and utilize your knowledge to benefit the organization.”

The success of the first nanomaterials course encouraged Patel to expand his class into specialty fields, designing a two-day nanoenergetics class taught by himself and Victor Stepanov, a senior scientist at EWMTD.

Stepanov works with nano-organic energetics (RDX, HMX, CL-20) and inorganic materials (metals.) He is responsible for creating the first nanoorganic energetic known as nano-RDX. He is involved in research aimed at understanding the various properties of nanoenergetics including sensitivity, performance, and mechanical characteristics. He and Patel teach the nanoenergetics class that was first offered last fall and due to high demand is expected to be offered annually. The next one will be held in September.

“We always ask for everyone’s feedback. And, after our first class, everyone said ‘[Picatinny] is the home of the Army’s lethality–why did we not talk about nanoenergetics?’ So, in response to the student’s feedback, we implemented that nanoenergetics course,” said Patel. “Besides, in the long run, you’ll probably replace most energetics with nano-energetics, as they have far too many advantages.”

TECHNOLOGY EVOLUTION

Since all living things are a form of nanotechnology manipulated by the forces of nature, the history of nanotechnology dates back to the emergence of life. However, a more concrete example can be traced back to ancient times, when nanomaterials were manipulated to create gold and silver art such as Lycurgus Cup, a 4th century Roman glass [I’ve added more about the Lycurgus Cup later in this post].

According to Stepanov, ARDEC’s interest in nanotechnology gained significant momentum approximately 20 years ago. The initiative at ARDEC was directly tied to the emergence of advanced technologies needed for production and characterization of nanomaterials, and was concurrent with adoption of nanotechnologies in other fields such as pharmaceuticals.

In 2010, an article in The Picatinny Voice titled “Tiny particles, big impact: Nanotechnology to help warfighters” discussed Picatinny’s ongoing research on nanopowders.

It noted that Picatinny’s Nanotechnology Lab is the largest facility in North America to produce nanopowders and nanomaterials, which are used to create nanoexplosives.

It also mentioned how using nanomaterials helped to develop lightweight composites as an alternative to traditional steel.

The more recent heightened study is due to the evolution of technology, which has allowed engineers and scientists to be more productive and made nanotechnology more ubiquitous throughout the military.

“Not too long ago making milligram quantities of nanoexplosives was challenging. Now, we have technologies that allow us make pounds of nanoexplosives per hour at low cost,” said Stepanov.

Pilot scale production of nanoexplosives is currently being performed at ARDEC, lead by Ashok Surapaneni of the Explosives Development Branch.

The broad interest in developing nanoenergetics such as nano-RDX and nano-HMX is their remarkably low initiation sensitivity.

These materials can thus be crucial in the development of safer next generation munitions that are much less vulnerable to accidental initiation.

SMALL CHANGES, BIG RESULTS

As a result, working with nanotechnology can have various payoffs, such as enhancing the performance of military products, said Patel. For instance, by manipulating nanomaterials, an engineer could make a weapon stronger, lighter, or increase its reactivity or durability.

“Generally, if you make something more safe, you make it less powerful,” said Stepanov. “But, with nanomaterials, you can make a product more safe and, in many cases, more powerful.”

There are two basic approaches to studying nanomaterials: bottom-up (building a large object atom by atom) and top-down (deconstructing a larger material.) Both approaches have been successfully employed in the development of nanoenergetics at ARDEC.

One of the challenges with manufacturing nonmaterials can be coping with shockwaves.

A shockwave initiates an explosive as it travels through a weapon’s main fill or the booster. When a shockwave travels through an energetic charge, it can hit small regions of defects, or voids, which heat up quickly and build pressure until the explosive reaches detonation. By using nanoenergetics, one could adjust the size and quantity of the defects and voids, so that the pressure isn’t as strong and ultimately prevent accidental detonation.

Nanomaterials also are difficult to process because they tend to agglomerate (stick together) and are also prone to Ostwald Ripening, or spontaneous growth of the crystals, which is especially pronounced at the nano-scale. This effect is commonly observed with ice cream, where ice can re-crystallize, resulting in a gritty texture.

“It’s a major production challenge because if you want to process nanomaterials–if you want to coat it with some polymer for explosives–any kind of medium that can dissolve these types of materials can promote ripening and you can end up with a product which no longer has the nanomaterial that you began with,” explained Stepanov.

However, nanotechnology research continues to grow at Picatinny as the research advances in the U.S. Army.

This ongoing development and future applicability encourages Patel and Stepanov to teach the nanomaterials and nanoenergetics course at Picatinny.

“I’m interested in making things better for the warfighter,” said Patel. “Nano-materials give you so many opportunities to do so. Also, as a scientist, it’s just a fascinating realm because you always get these little interesting surprises.

“You can know all the material science and equations, but then you get in the nano-world, and there’s something like a wrinkle–something you wouldn’t expect,” Patel added.

“It satisfies three deep needs: getting the warfighter technology, producing something of value, and it’s fun. You always see something new.”

Medieval church windows and the Lycurgus Cup

The shade of red in medieval church window glass is said to have been achieved by the use of gold nanoparticles. There is a source which claims the colour is due to copper rather than gold. I have not had to time to pursue the controversy such as it is but do have November 1, 2010 posting about stained glass and medieval churches which may prove of interest.

As for the Lycurgus Cup, it’s from the 4th century (CE or AD) and is an outstanding example of Roman art and craft. The glass in the cup is dichroic (it looks green or red depending on how the light catches it). The effect was achieved with the presence of gold and silver nanoparticles in the glass. I have a more extensive description and pictures in a Sept. 21, 2010 posting.

Final note

There is an  army initiative involving an educational institution, the Massachusetts Institute of Technology (MIT). The initiative is the MIT Institute for Soldier Nanotechnologies.