Tag Archives: Purdue University

Boosting chip speeds with graphene

There’s a certain hysteria associated with chip speeds as engineers and computer scientists try to achieve the ever improved speed times that consumers have enjoyed for some decades. The question looms, is there some point at which we can no longer improve the speed? Well, we haven’t reached that point yet according to a June 18, 2015 news item on Nanotechnology Now,

Stanford engineers find a simple yet clever way to boost chip speeds: Inside each chip are millions of tiny wires to transport data; wrapping them in a protective layer of graphene could boost speeds by up to 30 percent. [emphasis mine]

A June 16, 2015 Stanford University news release by Tom Abate (also on EurekAlert but dated June 17, 2015), which originated the news item, describes how computer chips are currently designed and the redesign which yields more speed,

A typical computer chip includes millions of transistors connected with an extensive network of copper wires. Although chip wires are unimaginably short and thin compared to household wires both have one thing in common: in each case the copper is wrapped within a protective sheath.

For years a material called tantalum nitride has formed protective layer in chip wires.

Now Stanford-led experiments demonstrate that a different sheathing material, graphene, can help electrons scoot through tiny copper wires in chips more quickly.

Graphene is a single layer of carbon atoms arranged in a strong yet thin lattice. Stanford electrical engineer H.-S. Philip Wong says this modest fix, using graphene to wrap wires, could allow transistors to exchange data faster than is currently possible. And the advantages of using graphene would become greater in the future as transistors continue to shrink.

Wong led a team of six researchers, including two from the University of Wisconsin-Madison, who will present their findings at the Symposia of VLSI Technology and Circuits in Kyoto, a leading venue for the electronics industry.

Ling Li, a graduate student in electrical engineering at Stanford and first author of the research paper, explained why changing the exterior wrapper on connecting wires can have such a big impact on chip performance.

It begins with understanding the dual role of this protective layer: it isolates the copper from the silicon on the chip and also serve to conduct electricity.

On silicon chips, the transistors act like tiny gates to switch electrons on or off. That switching function is how transistors process data.

The copper wires between the transistors transport this data once it is processed.

The isolating material–currently tantalum nitride–keeps the copper from migrating into the silicon transistors and rendering them non-functional.

Why switch to graphene?

Two reasons, starting with the ceaseless desire to keep making electronic components smaller.

When the Stanford team used the thinnest possible layer of tantalum nitride needed to perform this isolating function, they found that the industry-standard was eight times thicker than the graphene layer that did the same work.

Graphene had a second advantage as a protective sheathing and here it’s important to differentiate how this outer layer functions in chip wires versus a household wires.

In house wires the outer layer insulates the copper to prevent electrocution or fires.

In a chip the layer around the wires is a barrier to prevent copper atoms from infiltrating the silicon. Were that to happen the transistors would cease to function. So the protective layer isolates the copper from the silicon

The Stanford experiment showed that graphene could perform this isolating role while also serving as an auxiliary conductor of electrons. Its lattice structure allows electrons to leap from carbon atom to carbon atom straight down the wire, while effectively containing the copper atoms within the copper wire.

These benefits–the thinness of the graphene layer and its dual role as isolator and auxiliary conductor–allow this new wire technology to carry more data between transistors, speeding up overall chip performance in the process.

In today’s chips the benefits are modest; a graphene isolator would boost wire speeds from four percent to 17 percent, depending on the length of the wire. [emphasis mine]

But as transistors and wires continue to shrink in size, the benefits of the ultrathin yet conductive graphene isolator become greater. [emphasis mine] The Stanford engineers estimate that their technology could increase wire speeds by 30 percent in the next two generations

The Stanford researchers think the promise of faster computing will induce other researchers to get interested in wires, and help to overcome some of the hurdles needed to take this proof of principle into common practice.

This would include techniques to grow graphene, especially growing it directly onto wires while chips are being mass-produced. In addition to his University of Wisconsin collaborator Professor Michael Arnold, Wong cited Purdue University Professor Zhihong Chen. Wong noted that the idea of using graphene as an isolator was inspired by Cornell University Professor Paul McEuen and his pioneering research on the basic properties of this marvelous material. Alexander Balandin of the University of California-Riverside has also made contributions to using graphene in chips.

“Graphene has been promised to benefit the electronics industry for a long time, and using it as a copper barrier is perhaps the first realization of this promise,” Wong said.

I gather they’ve decided to highlight the most optimistic outcomes.

Call for nanoHUB User Conference proposals *deadline extension*

The deadline for the conference is June 15, 2015. Here’s more from a June 6, 2015 nanoHUB announcement,

Conference Description: The nanoHUB User Conference brings together users from research, education, and industry to network and learn from each other as well as from the nanoHUB team. Join us this year at Purdue University and hear from experienced users how nanoHUB is integrated into their research/classrooms, discover how nanoHUB is used in projects, and learn how to apply this information through a series of workshops offered by nanoHUB experts.

Abstract submission deadline is June 15th, 2015. *The deadline has been extend to Monday, June 22, 2105.* Additional information and instructions can be found here.

The conference will be held August 31st – September 1st, 2015, at Purdue University in West Lafayette, Indiana, USA. Registration for the conference is now open at: http://nanohub.org/newsletter/track/click/?t=IDAgRTVDNTAxNiBFNTQ1MTU1IDI0MDQ3NzM0MzUxNTI0RjFFNTI1OA%3D%3D&l=https%3A%2F%2Fnanohub.org%2Fgroups%2Fconference%2Fregistration


Abstract Submissions Deadline

June 15th, 2015 *Extended to Monday, June 22, 2015*

Authors Notified of Acceptance

July 15th, 2015

Poster Submissions Deadline

August 1st, 2015

For anyone who read this out of curiosity, here’s a brief description of nanoHUB from the website’s About Us webpage,

What is nanoHUB.org?

nanoHUB.org is the premier place for computational nanotechnology research, education, and collaboration. Our site hosts a rapidly growing collection of Simulation Programs for nanoscale phenomena that run in the cloud and are accessible through a web browser. In addition to simulation devices, nanoHUB provides Online Presentations, Courses, Learning Modules, Podcasts, Animations, Teaching Materials, and more. These resources help users learn about our simulation programs and about nanotechnology in general. Our site offers researchers a venue to explore, collaborate, and publish content, as well. Much of these collaborative efforts occur via Workspaces and User groups.

Authors of content published on nanoHUB.org represent a broad and growing cross-section of the nanotechnology community. Their work impacts industry, education, and governmental organizations around the world, as shown by the animated user location map below. The majority of nanoHUB users are affiliated with academic institutions, while other individuals are part of government and industry groups. nanoHUB makes public detailed usage analysis for the site with a degree of transparency uncommon among other sites.

nanoHUB content has been cited over 1,100 times in the scientific literature. These papers collectively have an h-index of 57, and the majority of them are by authors not affiliated with the Network for Computational Nanotechnology, the project that produces nanoHUB. Through automated assessment of user behavior, we have identified over 1100 clusters at 185 institutions using nanoHUB tools in the classroom. nanoHUB annual uptime regularly exceeds 99 percent.

Getting back to the call, good luck to everyone who makes a submission.

*Deadline extension updated added June 15, 2015.

3D printing soft robots and flexible electronics with metal alloys

This research comes from Purdue University (Indiana, US) which seems to be on a publishing binge these days. From an April 7, 2015 news item on Nanowerk,

New research shows how inkjet-printing technology can be used to mass-produce electronic circuits made of liquid-metal alloys for “soft robots” and flexible electronics.

Elastic technologies could make possible a new class of pliable robots and stretchable garments that people might wear to interact with computers or for therapeutic purposes. However, new manufacturing techniques must be developed before soft machines become commercially feasible, said Rebecca Kramer, an assistant professor of mechanical engineering at Purdue University.

“We want to create stretchable electronics that might be compatible with soft machines, such as robots that need to squeeze through small spaces, or wearable technologies that aren’t restrictive of motion,” she said. “Conductors made from liquid metal can stretch and deform without breaking.”

A new potential manufacturing approach focuses on harnessing inkjet printing to create devices made of liquid alloys.

“This process now allows us to print flexible and stretchable conductors onto anything, including elastic materials and fabrics,” Kramer said.

An April 7, 2015 Purdue University news release (also on EurekAlert) by Emil Venere, which originated the news item, expands on the theme,

A research paper about the method will appear on April 18 [2015] in the journal Advanced Materials. The paper generally introduces the method, called mechanically sintered gallium-indium nanoparticles, and describes research leading up to the project. It was authored by postdoctoral researcher John William Boley, graduate student Edward L. White and Kramer.

A printable ink is made by dispersing the liquid metal in a non-metallic solvent using ultrasound, which breaks up the bulk liquid metal into nanoparticles. This nanoparticle-filled ink is compatible with inkjet printing.

“Liquid metal in its native form is not inkjet-able,” Kramer said. “So what we do is create liquid metal nanoparticles that are small enough to pass through an inkjet nozzle. Sonicating liquid metal in a carrier solvent, such as ethanol, both creates the nanoparticles and disperses them in the solvent. Then we can print the ink onto any substrate. The ethanol evaporates away so we are just left with liquid metal nanoparticles on a surface.”

After printing, the nanoparticles must be rejoined by applying light pressure, which renders the material conductive. This step is necessary because the liquid-metal nanoparticles are initially coated with oxidized gallium, which acts as a skin that prevents electrical conductivity.

“But it’s a fragile skin, so when you apply pressure it breaks the skin and everything coalesces into one uniform film,” Kramer said. “We can do this either by stamping or by dragging something across the surface, such as the sharp edge of a silicon tip.”

The approach makes it possible to select which portions to activate depending on particular designs, suggesting that a blank film might be manufactured for a multitude of potential applications.

“We selectively activate what electronics we want to turn on by applying pressure to just those areas,” said Kramer, who this year was awarded an Early Career Development award from the National Science Foundation, which supports research to determine how to best develop the liquid-metal ink.

The process could make it possible to rapidly mass-produce large quantities of the film.

Future research will explore how the interaction between the ink and the surface being printed on might be conducive to the production of specific types of devices.

“For example, how do the nanoparticles orient themselves on hydrophobic versus hydrophilic surfaces? How can we formulate the ink and exploit its interaction with a surface to enable self-assembly of the particles?” she said.

The researchers also will study and model how individual particles rupture when pressure is applied, providing information that could allow the manufacture of ultrathin traces and new types of sensors.

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

Nanoparticles: Mechanically Sintered Gallium–Indium Nanoparticles by John William Boley, Edward L. White and Rebecca K. Kramer. Advanced Materials Volume 27, Issue 14, page 2270, April 8, 2015 DOI: 10.1002/adma.201570094 Article first published online: 7 APR 2015

© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

This article is behind a paywall.

Cellullose nanocrystals (CNC) and better concrete

Earlier this week in a March 30, 2015 post, I was bemoaning the dearth of applications for cellulose nanocrystals (CNC) with concomitant poor prospects for commercialization and problems for producers such as Canada’s CelluForce. Possibly this work at Purdue University (Indiana, US) will help address some of those issues (from a March 31, 2015 news item on Nanowerk),

Cellulose nanocrystals derived from industrial byproducts have been shown to increase the strength of concrete, representing a potential renewable additive to improve the ubiquitous construction material.

The cellulose nanocrystals (CNCs) could be refined from byproducts generated in the paper, bioenergy, agriculture and pulp industries. They are extracted from structures called cellulose microfibrils, which help to give plants and trees their high strength, lightweight and resilience. Now, researchers at Purdue University have demonstrated that the cellulose nanocrystals can increase the tensile strength of concrete by 30 percent.

A March 31, 2015 Purdue University news release by Emil Venere, which originated the news item, further describes the research published in print as of February 2015 (Note: A link has been removed),

One factor limiting the strength and durability of today’s concrete is that not all of the cement particles are hydrated after being mixed, leaving pores and defects that hamper strength and durability.

“So, in essence, we are not using 100 percent of the cement,” Zavattieri [Pablo Zavattieri, an associate professor in the Lyles School of Civil Engineering] said.

However, the researchers have discovered that the cellulose nanocrystals increase the hydration of the concrete mixture, allowing more of it to cure and potentially altering the structure of concrete and strengthening it.  As a result, less concrete needs to be used.

The cellulose nanocrystals are about 3 to 20 nanometers wide by 50-500 nanometers long – or about 1/1,000th the width of a grain of sand – making them too small to study with light microscopes and difficult to measure with laboratory instruments. They come from a variety of biological sources, primarily trees and plants.

The concrete was studied using several analytical and imaging techniques. Because chemical reactions in concrete hardening are exothermic, some of the tests measured the amount of heat released, indicating an increase in hydration of the concrete. The researchers also hypothesized the precise location of the nanocrystals in the cement matrix and learned how they interact with cement particles in both fresh and hardened concrete. The nanocrystals were shown to form little inlets for water to better penetrate the concrete.

The research dovetails with the goals of P3Nano, a public-private partnership supporting development and use of wood-based nanomaterial for a wide-range of commercial products.

“The idea is to support and help Purdue further advance the CNC-Cement technology for full-scale field trials and the potential for commercialization,” Zavattieri said.

The researchers have provided an image,

This transmission electron microscope image shows cellulose nanocrystals, tiny structures derived from renewable sources that might be used to create a new class of biomaterials with many potential applications. The structures have been shown to increase the strength of concrete. (Purdue Life Sciences Microscopy Center)

This transmission electron microscope image shows cellulose nanocrystals, tiny structures derived from renewable sources that might be used to create a new class of biomaterials with many potential applications. The structures have been shown to increase the strength of concrete. (Purdue Life Sciences Microscopy Center)

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

The influence of cellulose nanocrystal additions on the performance of cement paste by Yizheng Cao, Pablo Zavaterri, Jeff Youngblood, Robert Moon, and Jason Weiss. Cement and Concrete Composites, Volume 56, February 2015, Pages 73–83  DOI: 10.1016/j.cemconcomp.2014.11.008 Available online 18 November 2014

The paper is behind a paywall.

One final note, cellulose nanocrystals (CNC) may also be referred to nanocrystalline cellulose (NCC).


Nano for car lubricants and for sensors on dashboards

I have two car-oriented news items today. The first concerns the introduction of carbon nanospheres into lubricants as a means of reducing friction. From a March 5, 2015 news item on Nanowerk,

Tiny, perfectly smooth carbon spheres added to motor oil have been shown to reduce friction and wear typically seen in engines by as much as 25 percent, suggesting a similar enhancement in fuel economy.

The researchers also have shown how to potentially mass-produce the spheres, making them hundreds of times faster than previously possible using ultrasound to speed chemical reactions in manufacturing.

“People have been making these spheres for about the last 10 years, but what we discovered was that instead of taking the 24 hours of synthesis normally needed, we can make them in 5 minutes,” said Vilas Pol, an associate professor of chemical engineering at Purdue University.

The spheres are 100-500 nanometers in diameter, a range that generally matches the “surface roughness” of moving engine components.

“So the spheres are able to help fill in these areas and reduce friction,” said mechanical engineering doctoral student Abdullah A. Alazemi.

A March 4, 2015 Purdue University news release by Emil Venere, which originated the news item, elaborates on the impact this finding could have (Note: A link has been removed),

Tests show friction is reduced by 10 percent to 25 percent when using motor oil containing 3 percent of the spheres by weight.

“Reducing friction by 10 to 25 percent would be a significant improvement,” Sadeghi said. “Many industries are trying to reduce friction through modification of lubricants. The primary benefit to reducing friction is improved fuel economy.”

Friction is greatest when an engine is starting and shutting off, so improved lubrication is especially needed at those times.

“Introducing microspheres helps separate the surfaces because the spheres are free to move,” Alazemi said. “It also is possible that these spheres are rolling and acting as little ball bearings, but further research is needed to confirm this.” [emphasis mine]

Findings indicate adding the spheres did not change the viscosity of the oil.

“It’s very important not to increase the viscosity because you want to maintain the fluidity of the oil so that it can penetrate within engine parts,” Alazemi said.

The spheres are created using ultrasound to produce bubbles in a fluid containing a chemical compound called resorcinol and formaldehyde. The bubbles expand and collapse, generating heat that drives chemical reactions to produce polymer particles. These polymeric particles are then heated in a furnace to about 900 degrees Celsius, yielding the perfectly smooth spheres.

“A major innovation is that professor Pol has shown how to make lots of these spheres, which is important for potential industrial applications,” Sadeghi said.

Etacheri said, “Electron microscopy images and Raman spectra taken before and after their use show the spheres are undamaged, suggesting they can withstand the punishing environment inside engines and other machinery.”

Funding was provided by Purdue’s School of Chemical Engineering. Electron microscopy studies were performed at the Birck Nanotechnology Center in Purdue’s Discovery Park.

Future research will include work to determine whether the spheres are rolling like tiny ball bearings or merely sliding. A rolling mechanism best reduces friction and would portend well for potential applications. Future research also will determine whether the resorcinol-formaldehyde particles might themselves be used as a lubricant additive without heating them to produce pure carbon spheres.

I’m not sure why the researcher is referring to microspheres as the measurements are at the nanoscale, which should mean these are ‘nanospheres’ or, as the researchers have it in the title for their paper, ‘submicrometer spheres’.

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

Ultrasmooth Submicrometer Carbon Spheres as Lubricant Additives for Friction and Wear Reduction by Abdullah A. Alazemi, Vinodkumar Etacheri, Arthur D. Dysart, Lars-Erik Stacke, Vilas G. Pol, and Farshid Sadeghi. ACS Appl. Mater. Interfaces, Article ASAP DOI: 10.1021/acsami.5b00099 Publication Date (Web): February 17, 2015
Copyright © 2015 American Chemical Society

This paper is behind a paywall but there is an instructive image freely available,

This image taken with an electron microscope shows that tiny carbon spheres added to motor oil reduce friction and wear typically seen in engines by as much as 25 percent, suggesting a similar enhancement in fuel economy. Purdue researchers also have shown how to potentially mass-produce the spheres. (Purdue University image)

This image taken with an electron microscope shows that tiny carbon spheres added to motor oil reduce friction and wear typically seen in engines by as much as 25 percent, suggesting a similar enhancement in fuel economy. Purdue researchers also have shown how to potentially mass-produce the spheres. (Purdue University image)

My second car item concerns thin films and touch. From a March 5, 2015 news item on Azonano (Note: A link has been removed),,

Canatu, a leading manufacturer of transparent conductive films, has in partnership with Schuster Group [based in Germany] and Display Solution AG [based in Germany], showcased a pioneering 3D encapsulated touch sensor for the automotive industry.

The partnership is delivering the first ever, button free, 3D shaped true multitouch panel for automotives, being the first to bring much anticipated touch applications to dashboards and paneling. The demonstrator provides an example of multi-functional display with 5 finger touch realized in IML [in mould labeling] technology.

A March 5, 2015 Canatu press release, which originated the news item, provides more details about the technology and some insight into future plans,

The demonstrator provides an example of multi-functional display with 5 finger touch realized in IML technology. The integration of touch applications to dashboards and other paneling in cars has long been a desired by automotive designers but a suitable technology was not available. Finally the technology is now here. Canatu’s CNB™ (Carbon NanoBud®) In-Mold Film, with its unique stretch properties provides a clear path to the eventual replacement of mechanical controls with 3D touch sensors. The touch application was made using an existing mass manufacturing tool and industry standard processes.

Specifically designed for automobile center consoles and dashboards, household machines, wearable devices, industrial user interfaces, commercial applications and consumer devices, CNB™ In-Mold Films can be easily formed into shape. The film is first patterned to the required touch functionality, then formed, then back-molded by injection molding, resulting in a unique 3D shape with multitouch functionality.

With a bending radius of 1mm, CNB™ In-Mold Films can bring touch to almost any surface imaginable. The unique properties of CNB™ In-Mold Films are unmatched as no other film on the market can be stretched 120% and molded without losing their conductivity.

You can find out more about Canatu, based in Finland, here.

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.

Nanomaterials and safety: Europe’s non-governmental agencies make recommendations; (US) Arizona State University initiative; and Japan’s voluntary carbon nanotube management

I have three news items which have one thing in common, they concern nanomaterials and safety. Two of these of items are fairly recent; the one about Japan has been sitting in my drafts folder for months and I’m including it here because if I don’t do it now, I never will.

First, there’s an April 7, 2014 news item on Nanowerk (h/t) about European non-governmental agencies (CIEL; the Center for International Environmental Law and its partners) and their recommendations regarding nanomaterials and safety. From the CIEL April 2014 news release,

CIEL and European partners* publish position paper on the regulation of nanomaterials at a meeting of EU competent authorities

*ClientEarth, The European Environmental Bureau, European citizen’s Organization for Standardisation, The European consumer voice in Standardisation –ANEC, and Health Care Without Harm, Bureau of European Consumers

… Current EU legislation does not guarantee that all nanomaterials on the market are safe by being assessed separately from the bulk form of the substance. Therefore, we ask the European Commission to come forward with concrete proposals for a comprehensive revision of the existing legal framework addressing the potential risks of nanomaterials.

1. Nanomaterials are different from other substances.

We are concerned that EU law does not take account of the fact that nano forms of a substance are different and have different intrinsic properties from their bulk counterpart. Therefore, we call for this principle to be explicitly established in the REACH, and Classification Labeling and Packaging (CLP) regulations, as well as in all other relevant legislation. To ensure adequate consideration, the submission of comprehensive substance identity and characterization data for all nanomaterials on the market, as defined by the Commission’s proposal for a nanomaterial definition, should be required.

Similarly, we call on the European Commission and EU Member States to ensure that nanomaterials do not benefit from the delays granted under REACH to phase-in substances, on the basis of information collected on their bulk form.

Further, nanomaterials, due to their properties, are generally much more reactive than their bulk counterpart, thereby increasing the risk of harmful impact of nanomaterials compared to an equivalent mass of bulk material. Therefore, the present REACH thresholds for the registration of nanomaterials should be lowered.

Before 2018, all nanomaterials on the market produced in amounts of over 10kg/year must be registered with ECHA on the basis of a full registration dossier specific to the nanoform.

2. Risk from nanomaterials must be assessed

Six years after the entry into force of the REACH registration requirements, only nine substances have been registered as nanomaterials despite the much wider number of substances already on the EU market, as demonstrated by existing inventories. Furthermore, the poor quality of those few nano registration dossiers does not enable their risks to be properly assessed. To confirm the conclusions of the Commission’s nano regulatory review assuming that not all nanomaterials are toxic, relevant EU legislation should be amended to ensure that all nanomaterials are adequately assessed for their hazardous properties.

Given the concerns about novel properties of nanomaterials, under REACH, all registration dossiers of nanomaterials must include a chemical safety assessment and must comply with the same information submission requirements currently required for substances classified as Carcinogenic, Mutagenic or Reprotoxic (CMRs).

3. Nanomaterials should be thoroughly evaluated

Pending the thorough risk assessment of nanomaterials demonstrated by comprehensive and up-to-date registration dossiers for all nanoforms on the market, we call on ECHA to systematically check compliance for all nanoforms, as well as check the compliance of all dossiers which, due to uncertainties in the description of their identity and characterization, are suspected of including substances in the nanoform. Further, the Community Roling Action Plan (CoRAP) list should include all identified substances in the nanoform and evaluation should be carried out without delay.

4. Information on nanomaterials must be collected and disseminated

All EU citizens have the right to know which products contain nanomaterials as well as the right to know about their risks to health and environment and overall level of exposure. Given the uncertainties surrounding nanomaterials, the Commission must guarantee that members of the public are in a position to exercise their right to know and to make informed choices pending thorough risk assessments of nanomaterials on the market.

Therefore, a publicly accessible inventory of nanomaterials and consumer products containing nanomaterials must be established at European level. Moreover, specific nano-labelling or declaration requirements must be established for all nano-containing products (detergents, aerosols, sprays, paints, medical devices, etc.) in addition to those applicable to food, cosmetics and biocides which are required under existing obligations.

5. REACH enforcement activities should tackle nanomaterials

REACH’s fundamental principle of “no data, no market” should be thoroughly implemented. Therefore, nanomaterials that are on the market without a meaningful minimum set of data to allow the assessment of their hazards and risks should be denied market access through enforcement activities. In the meantime, we ask the EU Member States and manufacturers to use a precautionary approach in the assessment, production, use and disposal of nanomaterials

This comes on the heels of CIEL’s March 2014 news release announcing a new three-year joint project concerning nanomaterials and safety and responsible development,

Supported by the VELUX foundations, CIEL and ECOS (the European Citizen’s Organization for Standardization) are launching a three-year project aiming to ensure that risk assessment methodologies and risk management tools help guide regulators towards the adoption of a precaution-based regulatory framework for the responsible development of nanomaterials in the EU and beyond.

Together with our project partner the German Öko-Institut, CIEL and ECOS will participate in the work of the standardization organizations Comité Européen de Normalisation and International Standards Organization, and this work of the OECD [Organization for Economic Cooperation and Development], especially related to health, environmental and safety aspects of nanomaterials and exposure and risk assessment. We will translate progress into understandable information and issue policy recommendations to guide regulators and support environmental NGOs in their campaigns for the safe and sustainable production and use of nanomaterials.

The VILLUM FOUNDATION and the VELUX FOUNDATION are non-profit foundations created by Villum Kann Rasmussen, the founder of the VELUX Group and other entities in the VKR Group, whose mission it is to bring daylight, fresh air and a better environment into people’s everyday lives.

Meanwhile in the US, an April 6, 2014 news item on Nanowerk announces a new research network, based at Arizona State University (ASU), devoted to studying health and environmental risks of nanomaterials,

Arizona State University researchers will lead a multi-university project to aid industry in understanding and predicting the potential health and environmental risks from nanomaterials.

Nanoparticles, which are approximately 1 to 100 nanometers in size, are used in an increasing number of consumer products to provide texture, resiliency and, in some cases, antibacterial protection.

The U.S. Environmental Protection Agency (EPA) has awarded a grant of $5 million over the next four years to support the LCnano Network as part of the Life Cycle of Nanomaterials project, which will focus on helping to ensure the safety of nanomaterials throughout their life cycles – from the manufacture to the use and disposal of the products that contain these engineered materials.

An April 1, 2014 ASU news release, which originated the news item, provides more details and includes information about project partners which I’m happy to note include nanoHUB and the Nanoscale Informal Science Education Network (NISENet) in addition to the other universities,

Paul Westerhoff is the LCnano Network director, as well as the associate dean of research for ASU’s Ira A. Fulton Schools of Engineering and a professor in the School of Sustainable Engineering and the Built Environment.

The project will team engineers, chemists, toxicologists and social scientists from ASU, Johns Hopkins, Duke, Carnegie Mellon, Purdue, Yale, Oregon’s state universities, the Colorado School of Mines and the University of Illinois-Chicago.

Engineered nanomaterials of silver, titanium, silica and carbon are among the most commonly used. They are dispersed in common liquids and food products, embedded in the polymers from which many products are made and attached to textiles, including clothing.

Nanomaterials provide clear benefits for many products, Westerhoff says, but there remains “a big knowledge gap” about how, or if, nanomaterials are released from consumer products into the environment as they move through their life cycles, eventually ending up in soils and water systems.

“We hope to help industry make sure that the kinds of products that engineered nanomaterials enable them to create are safe for the environment,” Westerhoff says.

“We will develop molecular-level fundamental theories to ensure the manufacturing processes for these products is safer,” he explains, “and provide databases of measurements of the properties and behavior of nanomaterials before, during and after their use in consumer products.”

Among the bigger questions the LCnano Network will investigate are whether nanomaterials can become toxic through exposure to other materials or the biological environs they come in contact with over the course of their life cycles, Westerhoff says.

The researchers will collaborate with industry – both large and small companies – and government laboratories to find ways of reducing such uncertainties.

Among the objectives is to provide a framework for product design and manufacturing that preserves the commercial value of the products using nanomaterials, but minimizes potentially adverse environmental and health hazards.

In pursuing that goal, the network team will also be developing technologies to better detect and predict potential nanomaterial impacts.

Beyond that, the LCnano Network also plans to increase awareness about efforts to protect public safety as engineered nanomaterials in products become more prevalent.

The grant will enable the project team to develop educational programs, including a museum exhibit about nanomaterials based on the LCnano Network project. The exhibit will be deployed through a partnership with the Arizona Science Center and researchers who have worked with the Nanoscale Informal Science Education Network.

The team also plans to make information about its research progress available on the nanotechnology industry website Nanohub.org.

“We hope to use Nanohub both as an internal virtual networking tool for the research team, and as a portal to post the outcomes and products of our research for public access,” Westerhoff says.

The grant will also support the participation of graduate students in the Science Outside the Lab program, which educates students on how science and engineering research can help shape public policy.

Other ASU faculty members involved in the LCnano Network project are:

• Pierre Herckes, associate professor, Department of Chemistry and Biochemistry, College of Liberal Arts and Sciences
• Kiril Hristovski, assistant professor, Department of Engineering, College of Technology and Innovation
• Thomas Seager, associate professor, School of Sustainable Engineering and the Built Environment
• David Guston, professor and director, Consortium for Science, Policy and Outcomes
• Ira Bennett, assistant research professor, Consortium for Science, Policy and Outcomes
• Jameson Wetmore, associate professor, Consortium for Science, Policy and Outcomes, and School of Human Evolution and Social Change

I hope to hear more about the LCnano Network as it progresses.

Finally, there was this Nov. 12, 2013 news item on Nanowerk about instituting  voluntary safety protocols for carbon nanotubes in Japan,

Technology Research Association for Single Wall Carbon Nanotubes (TASC)—a consortium of nine companies and the National Institute of Advanced Industrial Science and Technology (AIST) — is developing voluntary safety management techniques for carbon nanotubes (CNTs) under the project (no. P10024) “Innovative carbon nanotubes composite materials project toward achieving a low-carbon society,” which is sponsored by the New Energy and Industrial Technology Development Organization (NEDO).

Lynn Bergeson’s Nov. 15, 2013 posting on nanotech.lawbc.com provides a few more details abut the TASC/AIST carbon nanotube project (Note: A link has been removed),

Japan’s National Institute of Advanced Industrial Science and Technology (AIST) announced in October 2013 a voluntary guidance document on measuring airborne carbon nanotubes (CNT) in workplaces. … The guidance summarizes the available practical methods for measuring airborne CNTs:  (1) on-line aerosol measurement; (2) off-line quantitative analysis (e.g., thermal carbon analysis); and (3) sample collection for electron microscope observation. …

You can  download two protocol documents (Guide to measuring airborne carbon nanotubes in workplaces and/or The protocols of preparation, characterization and in vitro cell based assays for safety testing of carbon nanotubes), another has been published since Nov. 2013, from the AIST’s Developing voluntary safety management techniques for carbon nanotubes (CNTs): Protocol and Guide webpage., Both documents are also available in Japanese and you can link to the Japanese language version of the site from the webpage.

Researchers at Purdue University (Indiana, US) and at the Indian Institute of Technology Madras (Chennai, India) develop Star Trek-type ‘tricorders’

To be clear, the Star Trek-type ‘tricorder’ referred to in the heading is, in fact, a hand-held spectrometer and the research from Purdue University and the Indian Institute of Technology Madras represents a developmental leap forward, not a new product. From a March 26, 2014 news item on Azonano,

Nanotechnology is advancing tools likened to Star Trek’s “tricorder” that perform on-the-spot chemical analysis for a range of applications including medical testing, explosives detection and food safety.

Researchers found that when paper used to collect a sample was coated with carbon nanotubes, the voltage required was 1,000 times reduced, the signal was sharpened and the equipment was able to capture far more delicate molecules.

Dexter Johnson in his March 26, 2014 posting (Nanoclast blog on the IEEE [Institute of Electrical and Electronics Engineers] website) provides some background information about the race to miniaturize spectrometers (Note: A link has been removed),

Recent research has been relying on nanomaterials to build smaller spectrometers. Late last year, a group at the Technische Universität Dresden and the Fraunhofer Institute in Germany developed a novel, miniature spectrometer, based on metallic nanowires, that was small enough to fit into a mobile phone.

Dexter goes on to provide a summary about this latest research, which I strongly recommend reading, especially if you don’t have the patience to read the rest of the news release. The March 25, 2014 Purdue University news release by Elizabeth K. Gardner, which originated the news item, provides insight from the researchers,

“This is a big step in our efforts to create miniature, handheld mass spectrometers for the field,” said R. Graham Cooks, Purdue’s Henry B. Hass Distinguished Professor of Chemistry. “The dramatic decrease in power required means a reduction in battery size and cost to perform the experiments. The entire system is becoming lighter and cheaper, which brings it that much closer to being viable for easy, widespread use.”

Cooks and Thalappil Pradeep, a professor of chemistry at the Indian Institute of Technology Madras, Chennai, led the research.

“Taking science to the people is what is most important,” Pradeep said. “Mass spectrometry is a fantastic tool, but it is not yet on every physician’s table or in the pocket of agricultural inspectors and security guards. Great techniques have been developed, but we need to hone them into tools that are affordable, can be efficiently manufactured and easily used.”

The news release goes on to describe the research,

The National Science Foundation-funded study used an analysis technique developed by Cooks and his colleagues called PaperSpray™ ionization. The technique relies on a sample obtained by wiping an object or placing a drop of liquid on paper wet with a solvent to capture residues from the object’s surface. A small triangle is then cut from the paper and placed on a special attachment of the mass spectrometer where voltage is applied. The voltage creates an electric field that turns the mixture of solvent and residues into fine droplets containing ionized molecules that pop off and are vacuumed into the mass spectrometer for analysis. The mass spectrometer then identifies the sample’s ionized molecules by their mass.

The technique depends on a strong electric field and the nanotubes act like tiny antennas that create a strong electric field from a very small voltage. One volt over a few nanometers creates an electric field equivalent to 10 million volts over a centimeter, Pradeep said.

“The trick was to isolate these tiny, nanoscale antennae and keep them from bundling together because individual nanotubes must project out of the paper,” he said. “The carbon nanotubes work well and can be dispersed in water and applied on suitable substrates.”

The Nano Mission of the Government of India supported the research at the Indian Institute of Technology Madras and graduate students Rahul Narayanan and Depanjan Sarkar performed the experiments.

In addition to reducing the size of the battery required and energy cost to run the tests, the new technique also simplified the analysis by nearly eliminating background noise, Cooks said.

“Under these conditions, the analysis is nearly noise free and a sharp, clear signal of the sample is delivered,” he said. “We don’t know why this is – why background molecules that surround us in the air or from within the equipment aren’t being ionized and entering into the analysis. It’s a puzzling, but pleasant surprise.”

The reduced voltage required also makes the method gentler than the standard PaperSpray™ ionization techniques.

“It is a very soft method,” Cooks said. “Fragile molecules and complexes are able to hold together here when they otherwise wouldn’t. This could lead to other potential applications.”

The team plans to investigate the mechanisms behind the reduction in background noise and potential applications of the gentle method, but the most promising aspect of the new technique is its potential to miniaturize the mass spectrometry system, Cooks said.

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

Molecular Ionization from Carbon Nanotube Paper by Rahul Narayanan, Depanjan Sarkar, Prof. R. Graham Cooks, and Prof. Thalappil Pradeep. Angewandte Chemie International Edition Article first published online: 18 MAR 2014 DOI: 10.1002/anie.201311053

© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

This paper is behind a paywall.

Fundamental mechanical behaviour of cellulose nanocrystals (aka nanocrystalline cellulose)

Emil Venere at Purdue University offers an excellent explanation of why there’s so much international interest in cellulose nanocrystals (CNC aka, nanocrystalline cellulose [NCC]) in his Dec. 16, 2013 Purdue University (Indiana, US) news release (also on EurekAlert), Note: A link has been removed,

The same tiny cellulose crystals that give trees and plants their high strength, light weight and resilience, have now been shown to have the stiffness of steel.

The nanocrystals might be used to create a new class of biomaterials with wide-ranging applications, such as strengthening construction materials and automotive components.

Calculations using precise models based on the atomic structure of cellulose show the crystals have a stiffness of 206 gigapascals, which is comparable to steel, said Pablo D. Zavattieri, a Purdue University assistant professor of civil engineering.

Here’s an image of the cellulose crystals being examined,

This transmission electron microscope image shows cellulose nanocrystals, tiny structures that give trees and plants their high strength, light weight and resilience. The nanocrystals might be used to create a new class of biomaterials that would have a wide range of applications. (Purdue Life Sciences Microscopy Center)

This transmission electron microscope image shows cellulose nanocrystals, tiny structures that give trees and plants their high strength, light weight and resilience. The nanocrystals might be used to create a new class of biomaterials that would have a wide range of applications. (Purdue Life Sciences Microscopy Center)

You’ll notice this image is not enhanced and made pretty as compared to the images in my Dec. 16, 2013 posting about Bristol University’s Art of Science competition. It takes a lot of work to turn the types of images scientists use into ‘art’.

Getting back to the CNC, this news release was probably written by someone who’s not familiar with the other work being done in the field (university press officers typically write about a wide range of topics and cannot hope to have in depth knowledge on each topic) and so it’s being presented as if it is brand new information. In fact, there has been several years work done in five other national jurisdictions that I know of (Sweden, Finland, Canada, Brazil, and Israel) and there are likely more. That’s not including other US states pursuing research in this area, notably Wisconsin.

What I (taking into account  my limitations) find particularly exciting in this work is the detail they’ve been able to determine and the reference to quantum mechanics. Here’s more from the news release (Note: Links have been removed),

“It is very difficult to measure the properties of these crystals experimentally because they are really tiny,” Zavattieri said. “For the first time, we predicted their properties using quantum mechanics.”

The nanocrystals are about 3 nanometers wide by 500 nanometers long – or about 1/1,000th the width of a grain of sand – making them too small to study with light microscopes and difficult to measure with laboratory instruments.

The findings represent a milestone in understanding the fundamental mechanical behavior of the cellulose nanocrystals.

“It is also the first step towards a multiscale modeling approach to understand and predict the behavior of individual crystals, the interaction between them, and their interaction with other materials,” Zavattieri said. “This is important for the design of novel cellulose-based materials as other research groups are considering them for a huge variety of applications, ranging from electronics and medical devices to structural components for the automotive, civil and aerospace industries.”

From an applications perspective (which is what excites so much international interest),

The cellulose nanocrystals represent a potential green alternative to carbon nanotubes for reinforcing materials such as polymers and concrete. Applications for biomaterials made from the cellulose nanocrystals might include biodegradable plastic bags, textiles and wound dressings; flexible batteries made from electrically conductive paper; new drug-delivery technologies; transparent flexible displays for electronic devices; special filters for water purification; new types of sensors; and computer memory.

Cellulose could come from a variety of biological sources including trees, plants, algae, ocean-dwelling organisms called tunicates, and bacteria that create a protective web of cellulose.

“With this in mind, cellulose nanomaterials are inherently renewable, sustainable, biodegradable and carbon-neutral like the sources from which they were extracted,” Moon said. “They have the potential to be processed at industrial-scale quantities and at low cost compared to other materials.”

Biomaterials manufacturing could be a natural extension of the paper and biofuels industries, using technology that is already well-established for cellulose-based materials.

“Some of the byproducts of the paper industry now go to making biofuels, so we could just add another process to use the leftover cellulose to make a composite material,” Moon said. “The cellulose crystals are more difficult to break down into sugars to make liquid fuel. So let’s make a product out of it, building on the existing infrastructure of the pulp and paper industry.”

Their surface can be chemically modified to achieve different surface properties.

“For example, you might want to modify the surface so that it binds strongly with a reinforcing polymer to make a new type of tough composite material, or you might want to change the chemical characteristics so that it behaves differently with its environment,” Moon said.

Zavattieri plans to extend his research to study the properties of alpha-chitin, a material from the shells of organisms including lobsters, crabs, mollusks and insects. Alpha-chitin appears to have similar mechanical properties as cellulose.

“This material is also abundant, renewable and waste of the food industry,” he said.

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

Anisotropy of the Elastic Properties of Crystalline Cellulose Iβ from First Principles Density Functional Theory with Van der Waals Interactions by Fernando L. Dri, Louis G. Hector Jr., Robert J. Moon, Pablo D. Zavattieri.  Cellulose December 2013, Volume 20, Issue 6, pp 2703-2718. 10.1007/s10570-013-0071-8

This paper is behind a paywall although you can preview the first few pages.

Erasing time to create a temporal invisibility cloak

The idea of taking an eraser and just rubbing out embarrassing (or worse) incidents in one’s life is tempting but not yet possible despite efforts by researchers at Purdue University (Indiana, US). From a June 5, 2013 news item on ScienceDaily,

Researchers have demonstrated a method for “temporal cloaking” of optical communications, representing a potential tool to thwart would-be eavesdroppers and improve security for telecommunications.

“More work has to be done before this approach finds practical application, but it does use technology that could integrate smoothly into the existing telecommunications infrastructure,” said Purdue University graduate student Joseph Lukens, working with Andrew Weiner, the Scifres Family Distinguished Professor of Electrical and Computer Engineering.

Other researchers in 2012 invented temporal cloaking, but it cloaked only a tiny fraction — about a 10,000th of a percent — of the time available for sending data in optical communications. Now the Purdue researchers have increased that to about 46 percent, potentially making the concept practical for commercial applications.

The Purdue University June 5, 2013 news release, which originated the news item, describes the new technique,

The technique works by manipulating the phase, or timing, of light pulses. The propagation of light can be likened to waves in the ocean. If one wave is going up and interacts with another wave that’s going down, they cancel each other and the light has zero intensity. The phase determines the level of interference between these waves.

“By letting them interfere with each other you are able to make them add up to a one or a zero,” Lukens said. “The zero is a hole where there is nothing.”

Any data in regions where the signal is zero would be cloaked.

Controlling phase allows the transmission of signals in ones and zeros to send data over optical fibers. A critical piece of hardware is a component called a phase modulator, which is commonly found in optical communications to modify signals.

In temporal cloaking, two phase modulators are used to first create the holes and two more to  cover them up, making it look as though nothing was done to the signal.

“It’s a potentially higher level of security because it doesn’t even look like you are communicating,” Lukens said. “Eavesdroppers won’t realize the signal is cloaked because it looks like no signal is being sent.”

Such a technology also could find uses in the military, homeland security or law enforcement.

“It might be used to prevent communication between people, to corrupt their communication links without them knowing,” he said. “And you can turn it on and off, so if they suspected something strange was going on you could return it to normal communication.”

The technique could be improved to increase its operational bandwidth and the percentage of cloaking beyond 46 percent, he said.

In a July 14, 2011 posting I wrote about some of the research that laid the groundwork for this breakthrough at Purdue University,

Ian Sample in his July 13, 2011 posting on The Guardian Science blogs describes an entirely different approach, one that focusses on cloaking events rather than objects. From Samples’s posting,

The theoretical prospect of a “space-time” cloak – or “history editor” – was raised by Martin McCall and Paul Kinsler at Imperial College in a paper published earlier this year. The physicists explained that when light passes through a material, such as a lens, the light waves slow down. But it is possible to make a lens that splits the light in two, so that half – say the shorter wavelengths – speed up, while the other half, the longer wavelengths, slow down. This opens a gap in the light in which an event can be hidden, because half the light arrives before it has happened, and the other half arrives after the event.

In their paper, McCall and Kinsler outline a scenario whereby a video camera would be unable to record a crime being committed because there was a means of splitting the light such that 1/2 of it reached the camera before the crime occurred and the other 1/2  reached the camera afterwards. Fascinating, non?

It seems researchers at Cornell University have developed a device that can in a rudimentary fashion cloak events (from Samples’s posting),

The latest device, which has been shown to work for the first time by Moti Fridman and Alexander Gaeta at Cornell University, goes beyond the more familiar invisibility cloak, which aims to hide objects from view, by making entire events invisible.

Zeeya Merali in her extensive June 5, 2013 article (Temporal cloak erases data from history) for Nature provides an in depth explanation of the Purdue research,

To speed up the cloaking rate, Lukens and his colleagues exploited a wave phenomenon that was first discovered by British inventor Henry Fox Talbot in 1836. When a light wave passes through a series of parallel slits called a diffraction grating, it splits apart. The rays emanating from the slits combine on the other side to create an intricate interference pattern of peaks and troughs. Talbot discovered that this pattern repeats at regular intervals, creating what is now known as a Talbot carpet. There is also a temporal version of this effect in which you manipulate light over time to generate regular periods with zero light intensity, says Lukens. Data can be then be hidden in these holes in time.

Lukens’ team created its Talbot carpet in time by passing laser light through a ‘phase modulator’, a waveguide that also had an oscillating electrical voltage applied to it. As the voltage varied, the speed at which the light travelled through the waveguide was altered, splitting the light into its constituent frequencies and knocking these out of step. As predicted, at regular time intervals, the separate frequencies recombined destructively to generate time holes. Lukens’ team then used a second round of phase modulation to compress the energy further, expanding the duration of the time windows to 36 picoseconds (or 36 trillionths of a second).

The researchers tested the cloak to see if it was operating correctly by inserting a separate encoded data stream into the fibre during the time windows. They then applied two more rounds of phase modulation — to “undo the damage of the first two rounds”, says Lukens — decompressing the energy again and then combining the separated frequencies back into one. They confirmed that a user downstream would pick up the original laser signal alone, as though it had never been disturbed. The cloak successfully hid data added at a rate of 12.7 gigabits per second.

Unfortunately, the researchers were a little too successful and managed to erase the event entirely, which seems to answer a question I posed facetiously in my July 14, 2011 posting,

If you can’t see the object (light bending cloak), and you never saw the event (temporal cloak), did it exist and did it happen?

In addition to the military applications that Lukens imagines for temporal invisibility cloaks, Merali notes a another possibility in her Nature article,

Ironically, the first application of temporal cloaks may not be to hide data, but to help them to be read more accurately. The team has shown that splitting and recombining light waves in time creates increased periods in which the main data stream can be made immune to corruption by inserted data. “This could be useful to cut down crosstalk when multiple data streams share the same fibre,” says Lukens.

Gaeta agrees that the primary use for cloaking will probably be for innocent, mundane purposes. “People always imagine doing something illicit when they hear ‘cloaking’,” he says. “But these ways for manipulating light will probably be used to make current non-secret communication techniques more sophisticated.”

The research paper can be found here,

A temporal cloak at telecommunication data rate by Joseph M. Lukens, Daniel E. Leaird & Andrew M. Weiner. Nature (2013) doi:10.1038/nature12224 Published online 05 June 2013

This paper is behind a paywall. Fortunately, anyone can access my June 5, 2013 posting (Memories, science, archiving, and authenticity) which seems relevant here for two reasons. First, there’s a mention of a new open access initiative in the US which would make this research more freely available in the future with a proposal (there may be others as this initiative develops) called the Clearinghouse for the Open Research of the United States (CHORUS).  I imagine there would be some caveats and I notice that Nature magazine has signed up for this proposal. I think the second reason for mentioning yesterday’s post is pretty obvious, memory/erasing, etc.