Manufacturing Bits: Dec. 26

Polymer pen litho; beam steering; taming atoms.


Polymer pen litho
Using a polymer pen lithography technique, the Air Force Research Laboratory and Northwestern University have developed a quick way to discover new materials.

Researchers have developed a combinatorial library of tiny nanoparticles on a substrate. A combinatorial library, sometimes referred to as a megalibrary, is a collection of different structures. Each structure is encoded at different sites on a surface.

Let’s say you are trying to find a new material. Then, by applying a screening process to the substrate, you can find the best material for a given application.

The libraries are created using a technology called polymer pen lithography. Polymer pen lithography makes use of a tool, which has an array of thousands of tiny tips. The tips deposit individual polymer dots on the surface. Each dot consists of a different metal. During the process, the dots are heated, forming a single nanoparticle at a fixed size.

In the lab, researchers combined the megalibrary and an in situ Raman spectroscopy-based screening technique. The spectroscopy technique, dubbed ARES, has been devised by the Air Force Research Laboratory. Using this screening technique, researchers identified a gold-copper composition as a new catalyst for synthesizing single-walled carbon nanotubes. Carbon nanotubes are hard, cylindrical nanostructures with good electrical properties.

The screening process took less than one week. It is thousands of times faster than traditional screening methods.

Laser-induced heating of nanoparticles on micropillars for carbon nanotube growth. (Source: Northwestern University)

“By going small, we create two advantages in high throughput materials discovery,” said Chad Mirkin, a professor at Northwestern. “First, we can pack millions of features into square-centimeter areas, creating a path for making the largest and most complex libraries, to date. Second, by working at the sub-100 nanometer-length scale, size can become a library parameter, and much of the action, for example, in the field of catalysis, is on this length scale.”

Benji Maruyama, leader of the flexible materials and process research team at the Air Force Research Laboratory, added: “We were able to rapidly zero in on an optimal composition that produced the highest nanotube yield much faster than using conventional methods. The findings suggest we may have the ultimate discovery tool—a potential game changer in materials discovery.”

Beam steering
The U.S. Naval Research Laboratory has demonstrated a new nonmechanical chip-based beam steering technology.

The chip is known as a steerable electro-evanescent optical refractor (SEEOR). SEEORs were originally developed to manipulate shortwave infrared (SWIR) light. This is the same part of the spectrum used for telecommunications. SEEORs have also found applications in guidance systems for self-driving cars.

The device takes laser light in the mid-wavelength infrared (MWIR) as an input. Then, it steers the beam in two dimensions at the output. This is done without the need for mechanical devices. And it has better steering capabilities and higher scan speed rates than conventional methods.

“Given the low size, weight and power consumption and continuous steering capability, this technology represents a promising path forward for MWIR beam-steering technologies,” said Jesse Frantz, research physicist at NRL. “Mapping in the MWIR spectral range demonstrates useful potential in a variety of applications, such as chemical sensing and monitoring emissions from waste sites, refineries, and other industrial facilities.”

Top 10 breakthroughs
The U.S. Army Research Development and Engineering Command (RDECOM), the Army’s corporate research laboratory, has a mission to develop technologies to ensure dominant strategic land power.

RDECOM came up with a list of its top 10 “coolest” advances from 2018:

10. Quantum information
Governments, R&D organizations and companies are working on quantum computing. In the future, the military also plans to use quantum computers and sensors.

In 2018, the Army discovered “how two separated photons can now stay entangled without distortion.” The findings were published in the journal Nature.

9. Ultra-broadband atomic antenna
Traditional antenna work, but the technology is sometimes limited. The Army is developing quantum antenna. The antenna makes use of atoms, which are excited to high energy levels. The atoms move into quantum states and achieve fast communication rates than today’s antenna.

In 2018, the Army presented its findings on a new quantum receiver. This research was published in Applied Physics Letters.

8. Neuromorphic computing
The industry is developing neuromorphic computing. So is the Army. Traditional computing makes use of processors, memory and storage. In neuromorphic computing, though, the idea is to mimic the brain to solve problems. To perform these tasks, the industry is working on next-generation memory types.

In 2018, the Army discussed this in IEEE Transactions on Circuits and Systems.

7. Inside a gas turbine’s combustor
Researchers are developing future gas turbine combustors, which may operate on alternative jet fuels. This, in turn, would boost the power density and efficiency in these systems.

However, it is difficult to image and measure the process of the atoms in future gas turbine combustors. But using X-ray metrology, the Army discovered a way to do this at Argonne National Laboratory’s Advanced Photon Source.

6. Thermal coatings
The helicopter is a key system in the battlefield. But sand is a problem in places like the desert. Sand may get into the blades or the turbine engine, causing various issues.

The Army created a new coating material, which rejects the sand particles. This in turn will allow the blades to survive longer. The Army published its findings in the Journal of Engineering for Gas Turbines and Power.

5. Nanocrystalline alloy
The Army developed a nanocrystalline alloy of copper and tantalum. The grains are about 50nm in size and arranged into clusters.

This alloy can withstand extreme impact and temperature, making it ideal for projectiles or armor. The Army published its findings to the journal Nature.

4. Powerful jumping robots
The Army sponsored research to discover the general principles of jumping in biological systems. For example, a grasshopper can jump far and fast, but it’s unclear how the insect performs this task.

The design principles are common to animals, plants, fungi and machines. In the future, the military may want to develop systems that can perform these tasks.

For example, it may use jumping robots. These systems may collect intelligence without being noticed. Researchers published their findings in the journal Science. The research was also conducted with Duke University, Carnegie Mellon University, University of Massachusetts Amherst, University of California Irvine and Harvard University.

3. New explosives
The Army is working on a new explosive material. The material, called BODN, is 50% more powerful than today’s TNT.
BODN is stable from a molecular standpoint. And unlike TNT, BODN is non-toxic. Researchers also developed a way to synthesize BODN. This research is published in Chemical & Engineering News.

2. AI agents
The Army has developed new machine learning techniques for robots or computers, which are referred to as artificial agents.

Researchers have devised new algorithms, called Deep TAMER. The program enables these systems to perform tasks by interacting with a human instructor. These techniques use programs to help systems learn faster with less data.

1. Taming the atom
The Army has found a way to release energy from the nucleus of an atom in a controlled manner. This is not a nuclear reaction. In the lab, “researchers arranged electrons at just the right speeds to be captured by atoms, tickling their nuclei to release energy. This significant scientific achievement, published in the journal Nature, marks a step in the Army’s quest to find and access alternative energy sources.”

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