Tag Archives: US Air Force

From flubber to thubber

Flubber (flying rubber) is an imaginary material that provided a plot point for two Disney science fiction comedies, The Absent-Minded Professor in 1961 which was remade in 1997 as Flubber. By contrast, ‘thubber’ (thermally conductive rubber) is a real life new material developed at Carnegie Mellon University (US).

A Feb. 13, 2017 news item on phys.org makes the announcement (Note: A link has been removed),

Carmel Majidi and Jonathan Malen of Carnegie Mellon University have developed a thermally conductive rubber material that represents a breakthrough for creating soft, stretchable machines and electronics. The findings were published in Proceedings of the National Academy of Sciences this week.

The new material, nicknamed “thubber,” is an electrically insulating composite that exhibits an unprecedented combination of metal-like thermal conductivity, elasticity similar to soft, biological tissue, and can stretch over six times its initial length.

A Feb.13, 2017 Carnegie Mellon University news release (also on EurekAlert), which originated the news item, provides more detail (Note A link has been removed),

“Our combination of high thermal conductivity and elasticity is especially critical for rapid heat dissipation in applications such as wearable computing and soft robotics, which require mechanical compliance and stretchable functionality,” said Majidi, an associate professor of mechanical engineering.

Applications could extend to industries like athletic wear and sports medicine—think of lighted clothing for runners and heated garments for injury therapy. Advanced manufacturing, energy, and transportation are other areas where stretchable electronic material could have an impact.

“Until now, high power devices have had to be affixed to rigid, inflexible mounts that were the only technology able to dissipate heat efficiently,” said Malen, an associate professor of mechanical engineering. “Now, we can create stretchable mounts for LED lights or computer processors that enable high performance without overheating in applications that demand flexibility, such as light-up fabrics and iPads that fold into your wallet.”

The key ingredient in “thubber” is a suspension of non-toxic, liquid metal microdroplets. The liquid state allows the metal to deform with the surrounding rubber at room temperature. When the rubber is pre-stretched, the droplets form elongated pathways that are efficient for heat travel. Despite the amount of metal, the material is also electrically insulating.

To demonstrate these findings, the team mounted an LED light onto a strip of the material to create a safety lamp worn around a jogger’s leg. The “thubber” dissipated the heat from the LED, which would have otherwise burned the jogger. The researchers also created a soft robotic fish that swims with a “thubber” tail, without using conventional motors or gears.

“As the field of flexible electronics grows, there will be a greater need for materials like ours,” said Majidi. “We can also see it used for artificial muscles that power bio-inspired robots.”

Majidi and Malen acknowledge the efforts of lead authors Michael Bartlett, Navid Kazem, and Matthew Powell-Palm in performing this multidisciplinary work. They also acknowledge funding from the Air Force, NASA, and the Army Research Office.

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

High thermal conductivity in soft elastomers with elongated liquid metal inclusions by Michael D. Bartlett, Navid Kazem, Matthew J. Powell-Palm, Xiaonan Huang, Wenhuan Sun, Jonathan A. Malen, and Carmel Majidi.  Proceedings of the National Academy of Sciences of the United States of America (PNAS, Proceedings of the National Academy of Sciences) doi: 10.1073/pnas.1616377114

This paper is open access.

Carbon nanotubes that can outperform silicon

According to a Sept. 2, 2016 news item on phys.org, researchers at the University of Wisconsin-Madison have produced carbon nanotube transistors that outperform state-of-the-art silicon transistors,

For decades, scientists have tried to harness the unique properties of carbon nanotubes to create high-performance electronics that are faster or consume less power—resulting in longer battery life, faster wireless communication and faster processing speeds for devices like smartphones and laptops.

But a number of challenges have impeded the development of high-performance transistors made of carbon nanotubes, tiny cylinders made of carbon just one atom thick. Consequently, their performance has lagged far behind semiconductors such as silicon and gallium arsenide used in computer chips and personal electronics.

Now, for the first time, University of Wisconsin-Madison materials engineers have created carbon nanotube transistors that outperform state-of-the-art silicon transistors.

Led by Michael Arnold and Padma Gopalan, UW-Madison professors of materials science and engineering, the team’s carbon nanotube transistors achieved current that’s 1.9 times higher than silicon transistors. …

A Sept. 2, 2016 University of Wisconsin-Madison news release (also on EurekAlert) by Adam Malecek, which originated the news item, describes the research in more detail and notes that the technology has been patented,

“This achievement has been a dream of nanotechnology for the last 20 years,” says Arnold. “Making carbon nanotube transistors that are better than silicon transistors is a big milestone. This breakthrough in carbon nanotube transistor performance is a critical advance toward exploiting carbon nanotubes in logic, high-speed communications, and other semiconductor electronics technologies.”

This advance could pave the way for carbon nanotube transistors to replace silicon transistors and continue delivering the performance gains the computer industry relies on and that consumers demand. The new transistors are particularly promising for wireless communications technologies that require a lot of current flowing across a relatively small area.

As some of the best electrical conductors ever discovered, carbon nanotubes have long been recognized as a promising material for next-generation transistors.

Carbon nanotube transistors should be able to perform five times faster or use five times less energy than silicon transistors, according to extrapolations from single nanotube measurements. The nanotube’s ultra-small dimension makes it possible to rapidly change a current signal traveling across it, which could lead to substantial gains in the bandwidth of wireless communications devices.

But researchers have struggled to isolate purely carbon nanotubes, which are crucial, because metallic nanotube impurities act like copper wires and disrupt their semiconducting properties — like a short in an electronic device.

The UW–Madison team used polymers to selectively sort out the semiconducting nanotubes, achieving a solution of ultra-high-purity semiconducting carbon nanotubes.

“We’ve identified specific conditions in which you can get rid of nearly all metallic nanotubes, where we have less than 0.01 percent metallic nanotubes,” says Arnold.

Placement and alignment of the nanotubes is also difficult to control.

To make a good transistor, the nanotubes need to be aligned in just the right order, with just the right spacing, when assembled on a wafer. In 2014, the UW–Madison researchers overcame that challenge when they announced a technique, called “floating evaporative self-assembly,” that gives them this control.

The nanotubes must make good electrical contacts with the metal electrodes of the transistor. Because the polymer the UW–Madison researchers use to isolate the semiconducting nanotubes also acts like an insulating layer between the nanotubes and the electrodes, the team “baked” the nanotube arrays in a vacuum oven to remove the insulating layer. The result: excellent electrical contacts to the nanotubes.

The researchers also developed a treatment that removes residues from the nanotubes after they’re processed in solution.

“In our research, we’ve shown that we can simultaneously overcome all of these challenges of working with nanotubes, and that has allowed us to create these groundbreaking carbon nanotube transistors that surpass silicon and gallium arsenide transistors,” says Arnold.

The researchers benchmarked their carbon nanotube transistor against a silicon transistor of the same size, geometry and leakage current in order to make an apples-to-apples comparison.

They are continuing to work on adapting their device to match the geometry used in silicon transistors, which get smaller with each new generation. Work is also underway to develop high-performance radio frequency amplifiers that may be able to boost a cellphone signal. While the researchers have already scaled their alignment and deposition process to 1 inch by 1 inch wafers, they’re working on scaling the process up for commercial production.

Arnold says it’s exciting to finally reach the point where researchers can exploit the nanotubes to attain performance gains in actual technologies.

“There has been a lot of hype about carbon nanotubes that hasn’t been realized, and that has kind of soured many people’s outlook,” says Arnold. “But we think the hype is deserved. It has just taken decades of work for the materials science to catch up and allow us to effectively harness these materials.”

The researchers have patented their technology through the Wisconsin Alumni Research Foundation.

Interestingly, at least some of the research was publicly funded according to the news release,

Funding from the National Science Foundation, the Army Research Office and the Air Force supported their work.

Will the public ever benefit financially from this research?

US Air Force wants to merge classical and quantum physics

The US Air Force wants to merge classical and quantum physics for practical purposes according to a May 5, 2014 news item on Azonano,

The Air Force Office of Scientific Research has selected the Harvard School of Engineering and Applied Sciences (SEAS) to lead a multidisciplinary effort that will merge research in classical and quantum physics and accelerate the development of advanced optical technologies.

Federico Capasso, Robert L. Wallace Professor of Applied Physics and Vinton Hayes Senior Research Fellow in Electrical Engineering, will lead this Multidisciplinary University Research Initiative [MURI] with a world-class team of collaborators from Harvard, Columbia University, Purdue University, Stanford University, the University of Pennsylvania, Lund University, and the University of Southampton.

The grant is expected to advance physics and materials science in directions that could lead to very sophisticated lenses, communication technologies, quantum information devices, and imaging technologies.

“This is one of the world’s strongest possible teams,” said Capasso. “I am proud to lead this group of people, who are internationally renowned experts in their fields, and I believe we can really break new ground.”

A May 1, 2014 Harvard University School of Engineering and Applied Sciences news release, which originated the news item, provides a description of project focus: nanophotonics and metamaterials along with some details of Capasso’s work in these areas (Note: Links have been removed),

The premise of nanophotonics is that light can interact with matter in unusual ways when the material incorporates tiny metallic or dielectric features that are separated by a distance shorter than the wavelength of the light. Metamaterials are engineered materials that exploit these phenomena, producing strange effects, enabling light to bend unnaturally, twist into a vortex, or disappear entirely. Yet the fabrication of thick, or bulk, metamaterials—that manipulate light as it passes through the material—has proven very challenging.

Recent research by Capasso and others in the field has demonstrated that with the right device structure, the critical manipulations can actually be confined to the very surface of the material—what they have dubbed a “metasurface.” These metasurfaces can impart an instantaneous shift in the phase, amplitude, and polarization of light, effectively controlling optical properties on demand. Importantly, they can be created in the lab using fairly common fabrication techniques.

At Harvard, the research has produced devices like an extremely thin, flat lens, and a material that absorbs 99.75% of infrared light. But, so far, such devices have been built to order—brilliantly suited to a single task, but not tunable.

This project, however,is focused on the future (Note: Links have been removed),

“Can we make a rapidly configurable metasurface so that we can change it in real time and quickly? That’s really a visionary frontier,” said Capasso. “We want to go all the way from the fundamental physics to the material building blocks and then the actual devices, to arrive at some sort of system demonstration.”

The proposed research also goes further. A key thrust of the project involves combining nanophotonics with research in quantum photonics. By exploiting the quantum effects of luminescent atomic impurities in diamond, for example, physicists and engineers have shown that light can be captured, stored, manipulated, and emitted as a controlled stream of single photons. These types of devices are essential building blocks for the realization of secure quantum communication systems and quantum computers. By coupling these quantum systems with metasurfaces—creating so-called quantum metasurfaces—the team believes it is possible to achieve an unprecedented level of control over the emission of photons.

“Just 20 years ago, the notion that photons could be manipulated at the subwavelength scale was thought to be some exotic thing, far fetched and of very limited use,” said Capasso. “But basic research opens up new avenues. In hindsight we know that new discoveries tend to lead to other technology developments in unexpected ways.”

The research team includes experts in theoretical physics, metamaterials, nanophotonic circuitry, quantum devices, plasmonics, nanofabrication, and computational modeling. Co-principal investigator Marko Lončar is the Tiantsai Lin Professor of Electrical Engineering at Harvard SEAS. Co-PI Nanfang Yu, Ph.D. ’09, developed expertise in metasurfaces as a student in Capasso’s Harvard laboratory; he is now an assistant professor of applied physics at Columbia. Additional co-PIs include Alexandra Boltasseva and Vladimir Shalaev at Purdue, Mark Brongersma at Stanford, and Nader Engheta at the University of Pennsylvania. Lars Samuelson (Lund University) and Nikolay Zheludev (University of Southampton) will also participate.

The bulk of the funding will support talented graduate students at the lead institutions.

The project, titled “Active Metasurfaces for Advanced Wavefront Engineering and Waveguiding,” is among 24 planned MURI awards selected from 361 white papers and 88 detailed proposals evaluated by a panel of experts; each award is subject to successful negotiation. The anticipated amount of the Harvard-led grant is up to $6.5 million for three to five years.

For anyone who’s not familiar (that includes me, anyway) with MURI awards, there’s this from Wikipedia (Note: links have been removed),

Multidisciplinary University Research Initiative (MURI) is a basic research program sponsored by the US Department of Defense (DoD). Currently each MURI award is about $1.5 million a year for five years.

I gather that in addition to the Air Force, the Army and the Navy also award MURI funds.

US Air Force takes baby steps toward shapeshifting materials

When I see information about US military futuristic projects it’s usually from the US Army’s DARPA (Defense Advanced Research Projects Agency).  Consequently, I was surprised to notice that this shapeshifting project is being funded by the US Air Force Office of Scientific Research according to the July 11, 2012 news item on phys.org,

An international research team has received a $2.9 million grant from the Air Force Office of Scientific Research to design nanomaterials whose internal structure changes shape in response to stimuli such as heat or light.

Each of these novel materials will be constructed from three types of components: inorganic nanoparticles with desired optical or electrical properties; peptides that bond to these nanoparticles; and special molecules called spacers, which sit between the peptides and bend in the presence of heat, light or other triggers.

When stimulated, the spacers will cause the arrangement of nanoparticles within the material to morph — a process that can lead to interesting and useful effects.

Shape-shifting materials of the kind the researchers are planning to create could have use in applications including color-changing sensors and plasmonic circuits that divert light in two directions.

The news item originated from a July 11, 2012 news release from the State University of New York (SUNY) at Buffalo,

The project is being led by Paras Prasad, SUNY Distinguished Professor in the University at Buffalo’s departments of chemistry, physics, electrical engineering and medicine, and executive director of UB’s Institute for Lasers, Photonics and Biophotonics (ILPB). …

Prasad’s fellow investigators include Aidong Zhang, professor and chair of the Department of Computer Science and Engineering at UB; Mark T. Swihart, professor of chemical and biological engineering at UB and director of the UB 2020 Integrated Nanostructured Systems Strategic Strength; Tiffany R. Walsh, associate professor at the Institute for Frontier Materials at Deakin University in Australia; and Marc R. Knecht, associate professor of chemistry at the University of Miami.

The palette of parts the team will use to build the nanomaterials includes spacers of different sizes, along with seven types of nanoparticles — gold, silver, silica, iron-oxide, iron-platinum, cadmium-sulfide and zinc-sulfide.

To identify the combinations of components that will produce the most interesting materials, the scientists will use high-throughput experiments and data-mining techniques to screen and analyze the vast number of possible combinations of nanostructures, biomolecular linking elements (the peptides) and assembly conditions.

“One of our goals is to contribute to the fundamental understanding of how the spatial arrangement of nanoscale components in materials affects their optical, magnetic and plasmonic properties,” Prasad said. “The high-throughput techniques we are using were pioneered in the field of bioinformatics, but also have extraordinary promise in the exploration of advanced materials.”

Zhang said, “The computational capabilities offered by informatics and data mining will enable us to maximize the value of our data regarding the nanoassemblies, to generate and to construct new assemblies that span a wide range of inorganic and bimolecular components so as to achieve desired combinatorics-based properties.”

It’s not exactly the shapeshifting one sees in science fiction but this will be the real stuff (not to be confused with The Right Stuff, a 1983 movie about the US space travel programme of the late 1950s to 1960s).

Science comic books

Some time before Christmas I came across (via Twitter, sorry I can’t remember who) a listing of comic books that focus on science. The list is on a University of Texas at Dallas web space for their CINDI educational website. From the CINDI home page,

The Coupled Ion Neutral Dynamics Investigation (CINDI) is a joint NASA/US Air Force funded ionospheric (upper atmosphere) plasma sensors built by the Center for Space Sciences at the University of Texas at Dallas. This instrument package is now flying on the Air Force’s Communication/Navigation Outage Forecast Satellite (C/NOFS) launched in spring 2008. On this site you will find a collection of teaching and education resources for grades 6-9 about the CINDI project, the Earth’s atmosphere, space weather, the scale in the Earth-Moon system, satellites and rockets and more.

Amongst other outreach initiatives, they’ve produced a series of ‘Cindi’ comic books. Here’s a copy of one of the covers.

)”]This particular issue is intended for students from grades 6 – 9.

The Cindi series was featured in an article by Dan Stillman for NASA (US National Aeronautics and Space Administration). From the article,

… Cindi, a spiky-haired android space girl, and her two space dogs, Teks and Taks, are stars of a comic book series that just released its second installment. With more than enough colorful pictures to go around, the comic books serve up a hearty helping of knowledge about the CINDI mission and the ionosphere, with a side of humor.

“Science is threatening to a lot of people. And even if it’s not threatening, most people have this misconception that ‘science is too hard for me to understand,'” said Hairston, [Mark Hairston]who together with Urquhart [Mary Urquhart] dreamed up the Cindi character and storyline. “But a comic book is not threatening. It’s pretty, it’s entertaining, and it’s easy to understand. So we can get people to read — and read all the way to the end.

“It grabs their interest and attention, and once we have that, we can then smuggle an amazing amount of scientific ideas and concepts into their minds.”

Even for Cindi, it’s no easy task to explain how atoms become ions and what NASA’s CINDI instruments do as they fly aboard an Air Force research satellite. The first Cindi comic book — “Cindi in Space,” published in 2005 — breaks the ice with an analogy involving Cindi’s dogs.

Getting back to where I started, the organizers have created a list of other science-focused comic books including a series from the Solar-Terrestrial Environment Laboratory (STEL) at  Nagoya University (Japan),which are manga-influenced. At this time, nine have been translated into English. Here’s copy of the cover from their latest,

Cover for What is the Sun-Climate Relationship? manga (STEL project at Nagoya University, Japan)

The Cindi folks also mention Jim Ottaviani and G. T. Labs, which has produced a number of graphic novels/comic books including, Bone Sharps, Cowboys, and Thunder Lizards about 19th century dinosaur bone hunters and a very bitter feud between two of them, and Dignifying Science which features stories about women scientists. I went over to the G. T. Labs website where they were featuring their latest, Feynman which was published in August 2011 (from the Feynman webpage),

Physicist . . . Nobel winner . . . bestselling author . . . safe-cracker.

Feynman tells the story of a great man’s life, from his childhood in Long Island to his work on the Manhattan Project and the Challenger disaster. You’ll see him help build the first atomic bomb, give a lecture to Einstein, become a safecracker, try not to win a Nobel Prize (but do it anyway), fall in love, learn how to become an artist, and discover the world.

Anyone who ever wanted to know more about quantum electrodynamics, the fine art of the bongo drums, the outrageously obscure nation of Tuva, or the development and popularization of physics in the United States need look no further!

Feynman explores a wonderful life, lived to the fullest.

Ottaviani’s Dec. 14, 2011 blog posting notes this about Feynman,

Though come to think of it, the context is sort of crazy, as in Feynman is nominated for the American Association for the Advancement of Science’s [AAAS] SB&F Prize, and it was also featured on Oprah.com’s “BookFinder” last week.

Congratulations to Ottaviani and G. T. Labs. (Sidebar: The AAAS 2012 annual meeting will be in Vancouver, Canada this February.)

Memristor tidbit from an unexpected source

The US Air Force has funded research to enable memristors to be integrated into CMOS (complementary metal-oxide semiconductor) devices. From the news item on Nanowerk,

Dr. Wei Wang, CNSE [College of Nanoscale Science and Engineering] Assistant Professor and Senior Research Scientist of Nanoscale Engineering, and Dr. Nathaniel Cady, CNSE  Assistant Professor of Nanobioscience, received $460,000 in funding from the U.S. Air Force Research Laboratory (“AFRL”) to enable integration of CMOS devices with memristors – including the development of novel prototypes – to support a new computing paradigm. Early research shows significant promise for the development of smaller nanoelectronic computer architectures that generate new and efficient ways to perform computational tasks while consuming less power.

The work is being performed at the University of Albany where the CNSE resides. In total, they received over $2M in US federal funding for various nanotechnology research projects.

After the discussion about memristors (see below) a few months back, I’m tickled to see this development.

Articles listed with the most recent article first:

Science in the British election and CASE; memristor and artificial intelligence; The Secret in Their Eyes, an allegory for post-Junta Argentina?

Measuring professional and national scientific achievements; Canadian science policy conferences

New approaches for emerging technologies; memristor comments by Dr. Leon Chua; more about I’m a scientist

Memristors and nuances in a classification tug-of-war; NRC of Canada insights; rapping scientists

Interview about memristors with Forrest H Bennett III

The memristor rises; commercialization and academic research in the US; carbon nanotubes could be made safer than we thought

More on memristors and a little bit on food packaging and nano

Canada’s nano article numbers (part 2) plus memristor and L’Oreal updates

Memristors and green energy