Category Archives: electronics

‘Beleafing’ in magic; a new type of battery

A Jan. 28, 2016 news item on ScienceDaily announces the ‘beleaf’,

Scientists have a new recipe for batteries: Bake a leaf, and add sodium. They used a carbonized oak leaf, pumped full of sodium, as a demonstration battery’s negative terminal, or anode, according to a paper published yesterday in the journal ACS Applied Materials Interfaces.

Scientists baked a leaf to demonstrate a battery. Credit: Image courtesy of Maryland NanoCenter

Scientists baked a leaf to demonstrate a battery.
Credit: Image courtesy of Maryland NanoCenter

A Jan. ??, 2016 Maryland NanoCenter (University of Maryland) news release, which originated the news item, provides more information about the nature (pun intended) of the research,

“Leaves are so abundant. All we had to do was pick one up off the ground here on campus,” said Hongbian Li, a visiting professor at the University of Maryland’s department of materials science and engineering and one of the main authors of the paper. Li is a member of the faculty at the National Center for Nanoscience and Technology in Beijing, China.

Other studies have shown that melon skin, banana peels and peat moss can be used in this way, but a leaf needs less preparation.

The scientists are trying to make a battery using sodium where most rechargeable batteries sold today use lithium. Sodium would hold more charge, but can’t handle as many charge-and-discharge cycles as lithium can.

One of the roadblocks has been finding an anode material that is compatible with sodium, which is slightly larger than lithium. Some scientists have explored graphene, dotted with various materials to attract and retain the sodium, but these are time consuming and expensive to produce.  In this case, they simply heated the leaf for an hour at 1,000 degrees C (don’t try this at home) to burn off all but the underlying carbon structure.

The lower side of the maple [?] leaf is studded with pores for the leaf to absorb water. In this new design, the pores absorb the sodium electrolyte. At the top, the layers of carbon that made the leaf tough become sheets of nanostructured carbon to absorb the sodium that carries the charge.

“The natural shape of a leaf already matches a battery’s needs: a low surface area, which decreases defects; a lot of small structures packed closely together, which maximizes space; and internal structures of the right size and shape to be used with sodium electrolyte,” said Fei Shen, a visiting student in the department of materials science and engineering and the other main author of the paper.

“We have tried other natural materials, such as wood fiber, to make a battery,” said Liangbing Hu, an assistant professor of materials science and engineering. “A leaf is designed by nature to store energy for later use, and using leaves in this way could make large-scale storage environmentally friendly.”

The next step, Hu said, is “to investigate different types of leaves to find the best thickness, structure and flexibility” for electrical energy storage.  The researchers have no plans to commercialize at this time.

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

Carbonized-leaf Membrane with Anisotropic Surfaces for Sodium-ion Battery by Hongbian Li, Fei Shen, Wei Luo, Jiaqi Dai, Xiaogang Han, Yanan Chen, Yonggang Yao, Hongli Zhu, Kun Fu, Emily Hitz, and Liangbing Hu. ACS Appl. Mater. Interfaces, 2016, 8 (3), pp 2204–2210 DOI: 10.1021/acsami.5b10875 Publication Date (Web): January 4, 2016

Copyright © 2016 American Chemical Society

This paper is behind a paywall.

Cellulose-based nanogenerators to power biomedical implants?

This cellulose nanogenerator research comes from India. A Jan. 27, 2016 American Chemical Society (ACS) news release makes the announcement,

Implantable electronics that can deliver drugs, monitor vital signs and perform other health-related roles are on the horizon. But finding a way to power them remains a challenge. Now scientists have built a flexible nanogenerator out of cellulose, an abundant natural material, that could potentially harvest energy from the body — its heartbeats, blood flow and other almost imperceptible but constant movements. …

Efforts to convert the energy of motion — from footsteps, ocean waves, wind and other movement sources — are well underway. Many of these developing technologies are designed with the goal of powering everyday gadgets and even buildings. As such, they don’t need to bend and are often made with stiff materials. But to power biomedical devices inside the body, a flexible generator could provide more versatility. So Md. Mehebub Alam and Dipankar Mandal at Jadavpur University in India set out to design one.

The researchers turned to cellulose, the most abundant biopolymer on earth, and mixed it in a simple process with a kind of silicone called polydimethylsiloxane — the stuff of breast implants — and carbon nanotubes. Repeated pressing on the resulting nanogenerator lit up about two dozen LEDs instantly. It also charged capacitors that powered a portable LCD, a calculator and a wrist watch. And because cellulose is non-toxic, the researchers say the device could potentially be implanted in the body and harvest its internal stretches, vibrations and other movements [also known as, harvesting biomechanical motion].

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

Native Cellulose Microfiber-Based Hybrid Piezoelectric Generator for Mechanical Energy Harvesting Utility by
Md. Mehebub Alam and Dipankar Mandal. ACS Appl. Mater. Interfaces, 2016, 8 (3), pp 1555–1558 DOI: 10.1021/acsami.5b08168 Publication Date (Web): January 11, 2016

Copyright © 2016 American Chemical Society

This paper is behind a paywall.

I did take a peek at the paper to see if I could determine whether or not they had used wood-derived cellulose and whether cellulose nanocrystals had been used. Based on the references cited for the paper, I think the answer to both questions is yes.

My latest piece on harvesting biomechanical motion is a June 24, 2014 post where I highlight a research project in Korea and another one in the UK and give links to previous posts on the topic.

Plastic memristors for neural networks

There is a very nice explanation of memristors and computing systems from the Moscow Institute of Physics and Technology (MIPT). First their announcement, from a Jan. 27, 2016 news item on ScienceDaily,

A group of scientists has created a neural network based on polymeric memristors — devices that can potentially be used to build fundamentally new computers. These developments will primarily help in creating technologies for machine vision, hearing, and other machine sensory systems, and also for intelligent control systems in various fields of applications, including autonomous robots.

The authors of the new study focused on a promising area in the field of memristive neural networks – polymer-based memristors – and discovered that creating even the simplest perceptron is not that easy. In fact, it is so difficult that up until the publication of their paper in the journal Organic Electronics, there were no reports of any successful experiments (using organic materials). The experiments conducted at the Nano-, Bio-, Information and Cognitive Sciences and Technologies (NBIC) centre at the Kurchatov Institute by a joint team of Russian and Italian scientists demonstrated that it is possible to create very simple polyaniline-based neural networks. Furthermore, these networks are able to learn and perform specified logical operations.

A Jan. 27, 2016 MIPT press release on EurekAlert, which originated the news item, offers an explanation of memristors and a description of the research,

A memristor is an electric element similar to a conventional resistor. The difference between a memristor and a traditional element is that the electric resistance in a memristor is dependent on the charge passing through it, therefore it constantly changes its properties under the influence of an external signal: a memristor has a memory and at the same time is also able to change data encoded by its resistance state! In this sense, a memristor is similar to a synapse – a connection between two neurons in the brain that is able, with a high level of plasticity, to modify the efficiency of signal transmission between neurons under the influence of the transmission itself. A memristor enables scientists to build a “true” neural network, and the physical properties of memristors mean that at the very minimum they can be made as small as conventional chips.

Some estimates indicate that the size of a memristor can be reduced up to ten nanometers, and the technologies used in the manufacture of the experimental prototypes could, in theory, be scaled up to the level of mass production. However, as this is “in theory”, it does not mean that chips of a fundamentally new structure with neural networks will be available on the market any time soon, even in the next five years.

The plastic polyaniline was not chosen by chance. Previous studies demonstrated that it can be used to create individual memristors, so the scientists did not have to go through many different materials. Using a polyaniline solution, a glass substrate, and chromium electrodes, they created a prototype with dimensions that, at present, are much larger than those typically used in conventional microelectronics: the strip of the structure was approximately one millimeter wide (they decided to avoid miniaturization for the moment). All of the memristors were tested for their electrical characteristics: it was found that the current-voltage characteristic of the devices is in fact non-linear, which is in line with expectations. The memristors were then connected to a single neuromorphic network.

A current-voltage characteristic (or IV curve) is a graph where the horizontal axis represents voltage and the vertical axis the current. In conventional resistance, the IV curve is a straight line; in strict accordance with Ohm’s Law, current is proportional to voltage. For a memristor, however, it is not just the voltage that is important, but the change in voltage: if you begin to gradually increase the voltage supplied to the memristor, it will increase the current passing through it not in a linear fashion, but with a sharp bend in the graph and at a certain point its resistance will fall sharply.

Then if you begin to reduce the voltage, the memristor will remain in its conducting state for some time, after which it will change its properties rather sharply again to decrease its conductivity. Experimental samples with a voltage increase of 0.5V hardly allowed any current to pass through (around a few tenths of a microamp), but when the voltage was reduced by the same amount, the ammeter registered a figure of 5 microamps. Microamps are of course very small units, but in this case it is the contrast that is most significant: 0.1 μA to 5 μA is a difference of fifty times! This is more than enough to make a clear distinction between the two signals.

After checking the basic properties of individual memristors, the physicists conducted experiments to train the neural network. The training (it is a generally accepted term and is therefore written without inverted commas) involves applying electric pulses at random to the inputs of a perceptron. If a certain combination of electric pulses is applied to the inputs of a perceptron (e.g. a logic one and a logic zero at two inputs) and the perceptron gives the wrong answer, a special correcting pulse is applied to it, and after a certain number of repetitions all the internal parameters of the device (namely memristive resistance) reconfigure themselves, i.e. they are “trained” to give the correct answer.

The scientists demonstrated that after about a dozen attempts their new memristive network is capable of performing NAND logical operations, and then it is also able to learn to perform NOR operations. Since it is an operator or a conventional computer that is used to check for the correct answer, this method is called the supervised learning method.

Needless to say, an elementary perceptron of macroscopic dimensions with a characteristic reaction time of tenths or hundredths of a second is not an element that is ready for commercial production. However, as the researchers themselves note, their creation was made using inexpensive materials, and the reaction time will decrease as the size decreases: the first prototype was intentionally enlarged to make the work easier; it is physically possible to manufacture more compact chips. In addition, polyaniline can be used in attempts to make a three-dimensional structure by placing the memristors on top of one another in a multi-tiered structure (e.g. in the form of random intersections of thin polymer fibers), whereas modern silicon microelectronic systems, due to a number of technological limitations, are two-dimensional. The transition to the third dimension would potentially offer many new opportunities.

The press release goes to explain what the researchers mean when they mention a fundamentally different computer,

The common classification of computers is based either on their casing (desktop/laptop/tablet), or on the type of operating system used (Windows/MacOS/Linux). However, this is only a very simple classification from a user perspective, whereas specialists normally use an entirely different approach – an approach that is based on the principle of organizing computer operations. The computers that we are used to, whether they be tablets, desktop computers, or even on-board computers on spacecraft, are all devices with von Neumann architecture; without going into too much detail, they are devices based on independent processors, random access memory (RAM), and read only memory (ROM).

The memory stores the code of a program that is to be executed. A program is a set of instructions that command certain operations to be performed with data. Data are also stored in the memory* and are retrieved from it (and also written to it) in accordance with the program; the program’s instructions are performed by the processor. There may be several processors, they can work in parallel, data can be stored in a variety of ways – but there is always a fundamental division between the processor and the memory. Even if the computer is integrated into one single chip, it will still have separate elements for processing information and separate units for storing data. At present, all modern microelectronic systems are based on this particular principle and this is partly the reason why most people are not even aware that there may be other types of computer systems – without processors and memory.

*) if physically different elements are used to store data and store a program, the computer is said to be built using Harvard architecture. This method is used in certain microcontrollers, and in small specialized computing devices. The chip that controls the function of a refrigerator, lift, or car engine (in all these cases a “conventional” computer would be redundant) is a microcontroller. However, neither Harvard, nor von Neumann architectures allow the processing and storage of information to be combined into a single element of a computer system.

However, such systems do exist. Furthermore, if you look at the brain itself as a computer system (this is purely hypothetical at the moment: it is not yet known whether the function of the brain is reducible to computations), then you will see that it is not at all built like a computer with von Neumann architecture. Neural networks do not have a specialized computer or separate memory cells. Information is stored and processed in each and every neuron, one element of the computer system, and the human brain has approximately 100 billion of these elements. In addition, almost all of them are able to work in parallel (simultaneously), which is why the brain is able to process information with great efficiency and at such high speed. Artificial neural networks that are currently implemented on von Neumann computers only emulate these processes: emulation, i.e. step by step imitation of functions inevitably leads to a decrease in speed and an increase in energy consumption. In many cases this is not so critical, but in certain cases it can be.

Devices that do not simply imitate the function of neural networks, but are fundamentally the same could be used for a variety of tasks. Most importantly, neural networks are capable of pattern recognition; they are used as a basis for recognising handwritten text for example, or signature verification. When a certain pattern needs to be recognised and classified, such as a sound, an image, or characteristic changes on a graph, neural networks are actively used and it is in these fields where gaining an advantage in terms of speed and energy consumption is critical. In a control system for an autonomous flying robot every milliwatt-hour and every millisecond counts, just in the same way that a real-time system to process data from a collider detector cannot take too long to “think” about highlighting particle tracks that may be of interest to scientists from among a large number of other recorded events.

Bravo to the writer!

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

Hardware elementary perceptron based on polyaniline memristive devices by V.A. Demin. V. V. Erokhin, A.V. Emelyanov, S. Battistoni, G. Baldi, S. Iannotta, P.K. Kashkarov, M.V. Kovalchuk. Organic Electronics Volume 25, October 2015, Pages 16–20 doi:10.1016/j.orgel.2015.06.015

This paper is behind a paywall.

#BCTECH: preview of Summit, Jan. 18 – 19, 2016

It is the first and it is sold out. Fear Not! I have gotten a press pass so I can investigate a bit further. In the meantime, #BCTECH Summit 2016 is a joint venture between the province of British Columbia (BC, Canada) and the BC Innovation Council (BCIC), a crown corporation formerly known as the Science Council of British Columbia.  A Jan 6, 2016 BCIC news release tells the story,

With less than two weeks to go and tickets 95% sold out, world-renowned keynote speakers will reinforce technology’s increasing economic and social impact to more than 2,000 people during B.C.’s first #BCTECH Summit on Jan. 18 & 19, 2016.

With Microsoft confirmed as the title sponsor, the summit will feature numerous dynamic keynote speakers:

  •  Ray Kurzweil, inventor, futurist—described as “the restless genius”, with predictions that will change how people think about the future.
  •  Andrew Wilson, CEO, Electronic Arts—named one of the top people in business by Fortune magazine.
  •  T.K. “Ranga” Rengarajan, corporate vice-president, Microsoft—will explore how technology and the cloud is empowering Canadians and changing how we do business and interact in the digital world.
  •  Elyse Allan, president and CEO, GE Canada—named one of the 25 most powerful people in Canada.
  •  Eric Ries, pioneer of the Lean Startup movement—a new approach to business that’s being adopted around the world; changing the way companies are built and new products are launched.

In addition, panel discussions featuring B.C. business leaders and global thought leaders will explore the latest trends, including fintech, cleantech, big data and cyber security.

A technology showcase will feature B.C.’s most innovative technology at work, including robots, 3D printing and electric cars. A new exhibit, the 4D Portal, will take delegates on a journey of B.C. tech, from deep below the earth’s surface into outer space.

More than 500 high school and post-secondary students will also take part in the summit’s career showcase featuring speakers and exhibitors sharing the latest information about technology as a career choice that pays, on average, 60% more than the B.C. average.

As part of the career showcase, nearly 200 high school students will participate in a coding camp and learn basic coding skills. The coding camp will also be offered via live webcast so schools throughout the province can participate.

A key component of the summit will profile venture capital presentations made by 40 promising small- to medium-sized B.C. companies aiming to attract investors and proceed to the next stage of development.

B.C.’s technology sector, a key pillar of the BC Jobs Plan, is consistently growing faster than the economy overall. Its continued growth is integral to diversifying the Province’s economy, strengthening B.C.’s business landscape and creating jobs in B.C. communities.

The new $100 million venture capital BC Tech Fund, announced Dec. 8, 2015, is the first pillar of the comprehensive #BCTECH Strategy to be released in full at B.C.’s first #BCTECH Summit, Jan. 18 – 19, 2016. The conference is presented by the B.C. government in partnership with the BC Innovation Council (BCIC). To register or learn more, go to: http://bctechsummit.ca

Quotes:

Minister of Technology, Innovation and Citizens’ Services, Amrik Virk –

“Strengthening our technology sector is part of our commitment to support our diverse economy. The summit provides an unprecedented opportunity for like-minded individuals to get together and discuss ways of growing this sector and capitalizing from that growth.”

President and CEO, BCIC, Greg Caws –

“We are pleased to provide British Columbians from across the province with the opportunity to explore how technology impacts our lives and our businesses. Above all, the #BCTECH Summit will be a catalyst for all of us to embrace technology and an innovation mindset.”

President, Microsoft Canada, Janet Kennedy –

“Microsoft is proud to be the title sponsor of the #BCTECH Summit—an event that showcases B.C.’s vibrant technology industry. We are excited about the growth of B.C.’s tech sector and are pleased that we’re expanding our developer presence in Vancouver and supporting Canadian private and public sector organizations through our investments in Canadian data centres.”

Quick Facts:

  •  The technology sector directly employs more than 86,000 people, and wages for those jobs are 60% higher than B.C.’s industrial average.
  •  B.C.’s technology sector is growing faster than the overall economy. In 2013, it grew at a rate of 4.7%, higher than the 3.2% growth observed in the provincial economy.
  •  In 2013, the technology sector added $13.9 billion to B.C.’s GDP.
  •  B.C.’s 9,000 technology companies combined generated $23.3 billion in revenue in 2013.
  •  New technology companies are emerging at increasing rates throughout the province. In 2013, there was an addition of more than 700 new technology companies in B.C., an increase of 8% over the prior year.

I’m not a big fan of Kurzweil’s but the man can sell tickets and, in days past, he did develop some important software. You can find out more about him on his website and critiques can be found here on Quora, as well as, a thoughtful Nov. 5, 2012 piece by Gary Marcus for the New Yorker about Kurzweil’s latest book (“How to Create a Mind: The Secret of Human Thought Revealed”).

As for me, I’m most interested in the trade show/research row/technology showcase. Simon Fraser University sent out a Jan. 14, 2016 news release highlighting its participation in the trade show and summit (weirdly there was nothing from the other major local research institution, the University of British Columbia),

Simon Fraser University is a gold sponsor of the #BCTECH Summit a new two-day event presented by the B.C. government and the BC Innovation Council to showcase the province’s vibrant technology sector

 

Simon Fraser University will be highly visible at the inaugural #BCTECH Summit taking place on January 18-19 at the Vancouver Convention Centre.

 

In addition to technology displays from student entrepreneurs at the SFU Innovates booth, SFU research will be featured at both the Technology Showcase and Research Row. [emphasis mine] SFU representatives will be on hand at the Career Showcase to speak to secondary and post-secondary students who are interested in the industry. And several investment-ready companies affiliated with SFU will be pitching to elite investors.

 

During the summit, entrepreneurs, investors, researchers, students and government will explore new ideas on how to gain a competitive advantage for B.C. The event will spark discussion on directions for the province’s rapidly developing high tech sector, while several streams will illustrate and share new innovations.

 

“This event provides us with an opportunity to showcase how SFU students, faculty, alumni and client companies are stimulating innovation and creating jobs and opportunities for British Columbia,“ says SFU Vice-President Research Joy Johnson. “And it highlights the work we’ve been doing to inspire, develop and support impact-driven innovation and entrepreneurship through SFU Innovates.”

 

SFU Innovates was launched in October to synergize and strengthen the university’s activities and resources related to community and industry engagement, incubation and acceleration, entrepreneurship and social innovation.

 

Johnson will introduce the summit’s keynote address by Eric Ries, Silicon Valley entrepreneur and author of The Lean Startup, on How today’s Entrepreneurs Use Continuous Innovation to Create Radically Successful Businesses, on Jan. 18 [2016] at 10:45 a.m.

 

SFU Faculty of Applied Sciences professor Ryan D’Arcy will be a panelist at a session titled Industry Deep Dive – Healthcare, moderated by Paul Drohan, CEO, Life Sciences BC, on Jan. 19 [2016] at 11 a.m. He will share how Surrey’s thriving Innovation Boulevard (IB) is progressing. SFU is a founding partner of IB and contributes via the university’s research strengths in health and technology and its focus on health tech innovation.

 

Steven Jones, an SFU professor of molecular biology and biochemistry, and associate director and head of bioinformatics at the Michael Smith Genome Sciences Centre, BCCA [BC Cancer Agency], will participate on a panel titled Shaping the Future of Health, on Jan. 19 [2016] at 2:15 p.m., to be moderated by the Honourable Terry Lake, Minister of Health.

 

And Igor Faletski, CEO of Mobify (and an SFU alumnus) will participate in the “Why BC?” session to be moderated by Bill Tam, CEO of BCTIA [BC Technology Industry Association], on Jan. 18 [2016] at 11:30 a.m.

 

Students and delegates will also have the opportunity to explore the various research and technology showcases.

 

Backgrounder: SFU Innovations at #BCTECH Summit

 

Research Row

 

4D LABS will showcase how it has helped B.C.’s academic and industry tech clients turn their ideas into innovations. The facility has been instrumental in bringing numerous ideas out of the lab and into the marketplace, advancing a diverse range of technologies, including fuel cells, batteries, biosensors, security devices, pharmaceutical delivery, MEMS, and many more. As B.C.’s premier materials research institute, the open-access, $65 million state-of-the-art facility has helped to advance nearly 50 companies in the local tech sector.

 

• SFU researchers led by JC Liu of the Faculty of Applied Sciences will display their cloud gaming platform, Rhizome, utilizing the latest hardware support for both remote servers and local clients. The platform takes the first step towards bridging online gaming systems and the public cloud, accomplishing ultra-low latency and resulting in a low power consumption gaming experience. Their demo shows that gaming over virtualized cloud can be made possible with careful optimization and integration of different modules. They will also introduce CrowdNavigation, a complementary service to existing navigation systems that combats the “last mile puzzle” and helps drivers to determine the end of routes.

 

Molescope is a hand held tool that uses a smartphone to monitor skin for signs of cancer. The device is based on research that Maryam Sadeghi conducted during her doctoral studies at SFU and commercialized through her company, MetaOptima Inc., a former SFU Venture Connection client. The product was unveiled at the World Congress of Dermatology in 2015 and is also now available at the consumer level. Molescope enables people to monitor their moles and manage skin health.

 

Technology Showcase

 

• Engineering science professors Siamak Arzanpour and Edward Park will showcase their Wearable Lower Limb Anthropomorphic Exoskeleton (WLLAE) – a lightweight, battery-operated and ergonomic robotic system to help those with mobility issues improve their lives. The exoskeleton features joints and links that correspond to those of a human body and sync with motion. SFU has designed, manufactured and tested a proof-of-concept prototype and the current version can mimic all the motions of hip joints. Researchers anticipate the next generation of this system early this year. The prototype will be live-demoed as an example of a breakthrough innovation.

 

Venture Capital Presentations

 

Several SFU-affiliated companies were selected to present investment pitches to local and international venture capitalists at the summit, including:

 

H+ Technology, creator of Holus, an interactive, tabletop holographic platform that converts any digital content from your tablet, smartphone, PC or Mac into a 360-degree holographic experience. H+ was co-founded by three SFU alumni and was a former client company of the SFU incubator at the Harbour Centre campus.

 

Optigo Networks, a VentureLabs® client company that delivers next-generation security for the commercial Internet of Things.

 

Saltworks Technologies Inc., provider of advanced water treatment solutions and a company founded by two graduates of SFU’s Management of Technology MBA program.

 

Semios, a VentureLabs® client company and emerging leader in agricultural technology innovation.

 

VeloMetro Mobility Inc., a former SFU Venture Connection and current VentureLabs® client company with the mission to provide people with human-powered vehicles that parallel automobile functionality for urban use.

 

SFU Innovates Trade Show will include:

 

• H+ Technology (see above)

 

Shield X Technology, creators of Brainshield™, an impact-diverting decal for sports helmets that is the result of six years of R&D at SFU’s School of Mechatronics Systems Engineering at the Surrey campus. An SFU spinout, it is a current VentureLabs® client company.

 

• Acceleration Innovations, creator of Birth Alert, the first ever app-enabled, automatic and wireless contraction-monitoring device. Acceleration Innovations was founded by a team of students from the Technology Entrepreneurship@SFU program.

 

ORA Scents, a mobile device company created by an SFU Beedie School of Business undergrad student, that is introducing the world’s first app-enabled scent diffuser that enables users to create, control and share personalized scents in real-time. [Sounds like oPhone mentioned in my June 18, 2014 posting.)

 

Also presenting at the VentureLabs area within the BC Accelerator Network Pavilion will be: PHEMI Health Systems, Semios, XCo, U R In Control, TeamFit, Instant, Wearable Therapeutics, V7 Entertainment, ThinkValue, and Aspect Biosystems. Lungpacer Medical and Metacreative, both companies formed around SFU faculty research, will also have exhibits.

 

Prize draws will be held for projects from RADIUS Slingshot ventures The Capilano Tea House & Botanical Soda Co. and Naked Snacks.

I’m particularly interested in what 4D Labs is doing these days. (They used to brand themselves as a nanotechnology laboratory but they’ve moved on to what they see as more sophisticated branding. I’m just curious. Have they changed focus or is it nanotechnology under a new name?)

Self-assembly with porphine molecules

A Jan. 12, 2016 American Institute of Physics (AIP) news release by John Arnst (also on EurekAlert but dated Jan. 14, 2016) describes computational research into self-assembling nanodevices based on porphine molecules,

As we continue to shrink electronic components, top-down manufacturing methods begin to approach a physical limit at the nanoscale. Rather than continue to chip away at this limit, one solution of interest involves using the bottom-up self-assembly of molecular building blocks to build nanoscale devices.

Successful self-assembly is an elaborately choreographed dance, in which the attractive and repulsive forces within molecules, between each molecule and its neighbors, and between molecules and the surface that supports them, have to all be taken into account. To better understand the self-assembly process, researchers at the Technical University of Munich have characterized the contributions of all interaction components, such as covalent bonding and van der Waals interactions between molecules and between molecules and a surface.

“In an ideal case, the smallest possible device has the size of a single atom or molecule,” said Katharina Diller, who worked as a postdoctoral researcher in the group of Karsten Reuter at the Technical University of Munich. Reuter and his colleagues present their work this week in The Journal of Chemical Physics, from AIP Publishing.

One such example is a single-porphyrin switch, which occupies a surface area of only one square nanometer. [emphasis mine] The porphine molecule, which was the object of this study, is even smaller than this. Porphyrins are a group of ringed chemical compounds which notably include heme – responsible for transporting oxygen and carbon dioxide in the bloodstream – and chlorophyll. In synthetically-derived applications, porphyrins are studied for their potential uses as sensors, light-sensitive dyes in organic solar cells, and molecular magnets.

The researchers from TU Munich assessed the interactions of the porphyrin molecule 2H-porphine by using density functional theory, a quantum mechanical computational modelling method used to describe the electronic properties of molecules and materials. Their simulations were performed at the high-performance supercomputer SuperMUC at Leibniz-Rechenzentrum in Garching.

The metallic substrates the researchers chose for the porphyrin molecules to assemble on, the close packed single crystal surfaces of copper and silver, are widely used as substrates in surface science. This is due to the densely packed nature of the surfaces, which allow the molecules to exhibit a smooth adsorption environment. Additionally, copper and silver each react differently with porhyrins – the molecule adsorbs more strongly on copper, whereas silver does a better job of keeping the electronic structure of the molecule intact – allowing the researchers to monitor a variety of competing effects for future applications.

In their simulation, porphyrin molecules were placed on a copper or silver slab, which was repeated periodically to simulate an extended surface. After finding the optimal geometry in which the molecules would adsorb on the surface, the researchers altered the size of the metal slab to increase or decrease the distance between molecules, thus simulating different molecular coverages. The computational setup gave them a switch to turn the energy contributions of neighboring molecules on and off, in order to observe the interplay of the individual interactions.

Diller and Reuter, along with colleagues Reinhard Maurer and Moritz Müller, who is first author on the paper, found that the weak long-range van der Waals interactions yielded the largest contribution to the molecule-surface interaction, and showed that the often employed methods to quantify the electronic charges in the system have to be used with caution. Surprisingly, while interactions directly between molecules are negligible, the researcher found indications for surface-mediated molecule-molecule interactions at higher molecular coverages.

“The analysis of the electronic structure and the individual interaction components allows us to better understand the self-assembly of porphine adsorbed on copper and silver, and additionally enables predictions for more complex porphyrine analogues,” Diller said. “These conclusions, however, come without yet considering the effects of atomic motion at finite temperature, which we did not study in this work.”

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

Interfacial charge rearrangement and intermolecular interactions: Density-functional theory study of free-base porphine adsorbed on Ag(111) and Cu(111) by Moritz Müller, Katharina Diller, Reinhard J. Maurer, and Karsten Reuter. J. Chem. Phys. 144, 024701 (2016); http://dx.doi.org/10.1063/1.4938259

This paper appears to be open access.

Finally, the researchers have made this illustrative diagram titled ‘Energy’ available,

Caption: Schematic depiction of different energy terms contributing to the adsorption energy, and charge density difference of 2H-P after adsorption onto Cu(111) at 12.8 Angstrom separation. Credit: M. Müller/TU Munich

Caption: Schematic depiction of different energy terms contributing to the adsorption energy, and charge density difference of 2H-P after adsorption onto Cu(111) at 12.8 Angstrom separation. Credit: M. Müller/TU Munich

Graphene-boron nitride material research from Rice University (US) and Polytechnique Montréal (Canada)

A Jan. 13, 2016 Rice University news release (also on EurekAlert) highlights computational research on hybrid material (graphene-boron nitride),

Developing novel materials from the atoms up goes faster when some of the trial and error is eliminated. A new Rice University and Montreal Polytechnic study aims to do that for graphene and boron nitride hybrids.

Rice materials scientist Rouzbeh Shahsavari and Farzaneh Shayeganfar, a postdoctoral researcher at Montreal Polytechnic (also known as École Polytechnique de Montréal or Polytechnique de Montréal), designed computer simulations that combine graphene, the atom-thick form of carbon, with either carbon or boron nitride nanotubes.

Their hope is that such hybrids can leverage the best aspects of their constituent materials. Defining the properties of various combinations would simplify development for manufacturers who want to use these exotic materials in next-generation electronics. The researchers found not only electronic but also magnetic properties that could be useful.

Shahsavari’s lab studies materials to see how they can be made more efficient, functional and environmentally friendly. They include macroscale materials like cement and ceramics as well as nanoscale hybrids with unique properties.

“Whether it’s on the macro- or microscale, if we can know specifically what a hybrid will do before anyone goes to the trouble of fabricating it, we can save cost and time and perhaps enable new properties not possible with any of the constituents,” Shahsavari said.

His lab’s computer models simulate how the intrinsic energies of atoms influence each other as they bond into molecules. For the new work, the researchers modeled hybrid structures of graphene and carbon nanotubes and of graphene and boron nitride nanotubes.

“We wanted to investigate and compare the electronic and potentially magnetic properties of different junction configurations, including their stability, electronic band gaps and charge transfer,” he said. “Then we designed three different nanostructures with different junction geometry.”

Two were hybrids with graphene layers seamlessly joined to carbon nanotubes. The other was similar but, for the first time, they modeled a hybrid with boron nitride nanotubes. How the sheets and tubes merged determined the hybrid’s properties. They also built versions with nanotubes sandwiched between graphene layers.

Graphene is a perfect conductor when its atoms align as hexagonal rings, but the material becomes strained when it deforms to accommodate nanotubes in hybrids. The atoms balance their energies at these junctions by forming five-, seven- or eight-member rings. These all induce changes in the way electricity flows across the junctions, turning the hybrid material into a valuable semiconductor.

The researchers’ calculations allowed them to map out a number of effects. For example, it turned out the junctions of the hybrid system create pseudomagnetic fields.

“The pseudomagnetic field due to strain was reported earlier for graphene, but not these hybrid boron nitride and carbon nanostructures where strain is inherent to the system,” Shahsavari said. He noted the effect may be useful in spintronic and nano-transistor applications.

“The pseudomagnetic field causes charge carriers in the hybrid to circulate as if under the influence of an applied external magnetic field,” he said. “Thus, in view of the exceptional flexibility, strength and thermal conductivity of hybrid carbon and boron nitride systems, we propose the pseudomagnetic field may be a viable way to control the electronic structure of new materials.”

All the effects serve as a road map for nanoengineering applications, Shahsavari said.

“We’re laying the foundations for a range of tunable hybrid architectures, especially for boron nitride, which is as promising as graphene but much less explored,” he said. “Scientists have been studying all-carbon structures for years, but the development of boron nitride and other two-dimensional materials and their various combinations with each other gives us a rich set of possibilities for the design of materials with never-seen-before properties.”

Shahsavari is an assistant professor of civil and environmental engineering and of materials science and nanoengineering.

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Rice supported the research, and computational resources were provided by Calcul Quebec and Compute Canada.

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

Electronic and pseudomagnetic properties of hybrid carbon/boron-nitride nanomaterials via ab-initio calculations and elasticity theory by Farzaneh Shayeganfar and Rouzbeh Shahsavari. Carbon Volume 99, April 2016, Pages 523–532 doi:10.1016/j.carbon.2015.12.050

This paper is behind a paywall.

Here’s an image illustrating the hybrid material,

Caption: The calculated properties of a three-dimensional hybrid of graphene and boron nitride nanotubes would have pseudomagnetic properties, according to researchers at Rice University and Montreal Polytechnic. Credit: Shahsavari Lab/Rice University

Caption: The calculated properties of a three-dimensional hybrid of graphene and boron nitride nanotubes would have pseudomagnetic properties, according to researchers at Rice University and Montreal Polytechnic. Credit: Shahsavari Lab/Rice University

No more kevlar-wrapped lithium-ion batteries?

Current lithium-ion batteries present a fire hazard, which is why, last, year a team of researchers at the University of Michigan came up with a plan to prevent fires by wrapping the batteries in kevlar. My Jan. 30, 2015 post describes the research and provides some information about airplane fires caused by the use of lithium-ion batteries.

This year, a team of researchers at Stanford University (US) have invented a lithium-ion (li-ion) battery that shuts itself down when it overheats, according to a Jan. 12, 2016 news item on Nanotechnology Now,

Stanford researchers have developed the first lithium-ion battery that shuts down before overheating, then restarts immediately when the temperature cools.

The new technology could prevent the kind of fires that have prompted recalls and bans on a wide range of battery-powered devices, from recliners and computers to navigation systems and hoverboards [and on airplanes].

“People have tried different strategies to solve the problem of accidental fires in lithium-ion batteries,” said Zhenan Bao, a professor of chemical engineering at Stanford. “We’ve designed the first battery that can be shut down and revived over repeated heating and cooling cycles without compromising performance.”

Stanford has produced a video of Dr. Bao discussing her latest work,

A Jan. 11, 2016 Stanford University news release by Mark Schwartz, which originated the news item, provides more detail about li-ion batteries and the new fire prevention technology,

A typical lithium-ion battery consists of two electrodes and a liquid or gel electrolyte that carries charged particles between them. Puncturing, shorting or overcharging the battery generates heat. If the temperature reaches about 300 degrees Fahrenheit (150 degrees Celsius), the electrolyte could catch fire and trigger an explosion.

Several techniques have been used to prevent battery fires, such as adding flame retardants to the electrolyte. In 2014, Stanford engineer Yi Cui created a “smart” battery that provides ample warning before it gets too hot.

“Unfortunately, these techniques are irreversible, so the battery is no longer functional after it overheats,” said study co-author Cui, an associate professor of materials science and engineering and of photon science. “Clearly, in spite of the many efforts made thus far, battery safety remains an important concern and requires a new approach.”

Nanospikes

To address the problem Cui, Bao and postdoctoral scholar Zheng Chen turned to nanotechnology. Bao recently invented a wearable sensor to monitor human body temperature. The sensor is made of a plastic material embedded with tiny particles of nickel with nanoscale spikes protruding from their surface.

For the battery experiment, the researchers coated the spiky nickel particles with graphene, an atom-thick layer of carbon, and embedded the particles in a thin film of elastic polyethylene.

“We attached the polyethylene film to one of the battery electrodes so that an electric current could flow through it,” said Chen, lead author of the study. “To conduct electricity, the spiky particles have to physically touch one another. But during thermal expansion, polyethylene stretches. That causes the particles to spread apart, making the film nonconductive so that electricity can no longer flow through the battery.”

When the researchers heated the battery above 160 F (70 C), the polyethylene film quickly expanded like a balloon, causing the spiky particles to separate and the battery to shut down. But when the temperature dropped back down to 160 F (70 C), the polyethylene shrunk, the particles came back into contact, and the battery started generating electricity again.

“We can even tune the temperature higher or lower depending on how many particles we put in or what type of polymer materials we choose,” said Bao, who is also a professor, by courtesy, of chemistry and of materials science and engineering. “For example, we might want the battery to shut down at 50 C or 100 C.”

Reversible strategy

To test the stability of new material, the researchers repeatedly applied heat to the battery with a hot-air gun. Each time, the battery shut down when it got too hot and quickly resumed operating when the temperature cooled.

“Compared with previous approaches, our design provides a reliable, fast, reversible strategy that can achieve both high battery performance and improved safety,” Cui said. “This strategy holds great promise for practical battery applications.”

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

Fast and reversible thermoresponsive polymer switching materials for safer batteries by Zheng Chen, Po-Chun Hsu, Jeffrey Lopez, Yuzhang Li, John W. F. To, Nan Liu, Chao Wang, Sean C. Andrews, Jia Liu, Yi Cui, & Zhenan Bao. Nature Energy 1, Article number: 15009 (2016) doi:10.1038/nenergy.2015.9 Published online: 11 January 2016

This paper appears to be open access.

Nanowalls (like waffles) for touchscreens

ETH Zurich has announced a new technique for creating transparent electrodes in a Jan. 6, 2016 news item on ScienceDaily,

Transparent electrodes have been manufactured for use in touchscreens using a novel nanoprinting process. The new electrodes are some of the most transparent and conductive that have ever been developed.

From smartphones to the operating interfaces of ticket machines and cash dispensers, every touchscreen we use requires transparent electrodes: The devices’ glass surface is coated with a barely visible pattern made of conductive material. It is because of this that the devices recognise whether and where exactly a finger is touching the surface.

Here’s an image illustrating the new electrodes,

With a special mode of electrohydrodynamic ink-jet printing scientists can create a grid of ultra fine gold walls. (Visualisations: Ben Newton / Digit Works)

With a special mode of electrohydrodynamic ink-jet printing scientists can create a grid of ultra fine gold walls. (Visualisations: Ben Newton / Digit Works)

I think these electrodes resemble waffles,

[downloaded from https://github.com/jhermann/Stack-O-Waffles] Credit: jherman

[downloaded from https://github.com/jhermann/Stack-O-Waffles] Credit: jherman

Getting back to the electrodes themselves, a Jan. 6, 2016 ETH Zurich press release (also on EurekAlert*)by Fabio Bergamin, which originated the news item, provides more details,

Researchers under the direction of Dimos Poulikakos, Professor of Thermodynamics, have now used 3D print technology to create a new type of transparent electrode, which takes the form of a grid made of gold or silver “nanowalls” on a glass surface. The walls are so thin that they can hardly be seen with the naked eye. It is the first time that scientists have created nanowalls like these using 3D printing. The new electrodes have a higher conductivity and are more transparent than those made of indium tin oxide, the standard material used in smartphones and tablets today. This is a clear advantage: The more transparent the electrodes, the better the screen quality. And the more conductive they are, the more quickly and precisely the touchscreen will work.

Third dimension

“Indium tin oxide is used because the material has a relatively high degree of transparency and the production of thin layers has been well researched, but it is only moderately conductive,” says Patrik Rohner, a PhD student in Poulikakos’ team. In order to produce more conductive electrodes, the ETH researchers opted for gold and silver, which conduct electricity much better. But because these metals are not transparent, the scientists had to make use of the third dimension. ETH professor Poulikakos explains: “If you want to achieve both high conductivity and transparency in wires made from these metals, you have a conflict of objectives. As the cross-sectional area of gold and silver wires grows, the conductivity increases, but the grid’s transparency decreases.”

The solution was to use metal walls only 80 to 500 nanometres thick, which are almost invisible when viewed from above. Because they are two to four times taller than they are wide, the cross-sectional area, and thus the conductivity, is sufficiently high.

Ink-jet printer with tiny print head

The researchers produced these tiny metal walls using a printing process known as Nanodrip, which Poulikakos and his colleagues developed three years ago. Its basic principle is a process called electrohydrodynamic ink-jet printing. In this process scientists use inks made from metal nanoparticles in a solvent; an electrical field draws ultra-small droplets of the metallic ink out of a glass capillary. The solvent evaporates quickly, allowing a three-dimensional structure to be built up drop by drop.

What is special about the Nanodrip process is that the droplets that come out of the glass capillary are about ten times smaller than the aperture itself. This allows for much smaller structures to be printed. “Imagine a water drop hanging from a tap that is turned off. And now imagine that another tiny droplet is hanging from this drop – we are only printing the tiny droplet,” Poulikakos explains. The researchers managed to create this special form of droplet by perfectly balancing the composition of metallic ink and the electromagnetic field used.

Cost-efficient production

The next big challenge will now be to upscale the method and develop the print process further so that it can be implemented on an industrial scale. To achieve this, the scientists are working with colleagues from ETH spin-off company Scrona.

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

Electrohydrodynamic NanoDrip Printing of High Aspect Ratio Metal Grid Transparent Electrodes by Julian Schneider, Patrick Rohner, Deepankur Thureja, Martin Schmid, Patrick Galliker, Dimos Poulikalos. Advanced Functional Materials DOI: 10.1002/adfm.201503705 First published: 15 December 2015

This paper is behind a paywall.

*'(also on EurekAlert)’ added on Jan. 7, 2016.

Promising new technique for controlled fabrication of nanowires

This research is the result of a collaboration between French, Italian, Australian, and Canadian researchers. From a Jan. 5, 2016 news item on *phys.org,

An international team of researchers including Professor Federico Rosei and members of his group at INRS (Institut national de la recherche scientifique) has developed a new strategy for fabricating atomically controlled carbon nanostructures used in molecular carbon-based electronics. An article just published in the prestigious journal Nature Communications presents their findings: the complete electronic structure of a conjugated organic polymer, and the influence of the substrate on its electronic properties.

A Jan. 5, 2016 INRS news release by Gisèle Bolduc, which originated the news item, indicates this is the beginning rather than an endpoint (Note: A link has been removed),

The researchers combined two procedures previously developed in Professor Rosei’s lab—molecular self-assembly and chain polymerization—to produce a network of long-range poly(para-phenylene) (PPP) nanowires on a copper (Cu) surface. Using advanced technologies such as scanning tunneling microscopy and photoelectron spectroscopy as well as theoretical models, they were able to describe the morphology and electronic structure of these nanostructures.

“We provide a complete description of the band structure and also highlight the strong interaction between the polymer and the substrate, which explains both the decreased bandgap and the metallic nature of the new chains. Even with this hybridization, the PPP bands display a quasi one-dimensional dispersion in conductive polymeric nanowires,” said Professor Federico Rosei, one of the authors of the study.

Although further research is needed to fully describe the electronic properties of these nanostructures, the polymer’s dispersion provides a spectroscopic record of the polymerization process of certain types of molecules on gold, silver, copper, and other surfaces. It’s a promising approach for similar semiconductor studies—an essential step in the development of actual devices.

The results of the study could be used in designing organic nanostructures, with significant potential applications in nanoelectronics, including photovoltaic devices, field-effect transistors, light-emitting diodes, and sensors.

About the article

This study was designed by Yannick Fagot-Revurat and Daniel Malterre of Université de Lorraine/CNRS, Federico Rosei of INRS, Josh Lipton-Duffin of the Institute for Future Environments (Australia), Giorgio Contini of the Italian National Research Council, and Dmytro F. Perepichka of McGill University. […]The researchers were generously supported by Conseil Franco-Québécois de coopération universitaire, the France–Italy International Program for Scientific Cooperation, the Natural Sciences and Engineering Research Council of Canada, Fonds québécois de recherche – Nature et technologies, and a Québec MEIE grant (in collaboration with Belgium).

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

Quasi one-dimensional band dispersion and surface metallization in long-range ordered polymeric wires by Guillaume Vasseur, Yannick Fagot-Revurat, Muriel Sicot, Bertrand Kierren, Luc Moreau, Daniel Malterre, Luis Cardenas, Gianluca Galeotti, Josh Lipton-Duffin, Federico Rosei, Marco Di Giovannantonio, Giorgio Contini, Patrick Le Fèvre, François Bertran, Liangbo Liang, Vincent Meunier, Dmitrii F. Perepichka. Nature Communications 7, Article number:  10235 doi:10.1038/ncomms10235 Published 04 January 2016

This is an open access paper.

*’ScienceDaily’ corrected to ‘phys.org’ on Tues., Jan. 5, 2016 at 1615 PST.

A bioelectronic future made possible with DNA-based electromechanical switch

DNA-based electronics are discussed in the context of a Dec. 14, 2015 news item by Beth Ellison for Azonano about research into electromechanical switches at the University of California at Davis,

Researchers from the University of California, Davis (UC Davis) and the University of Washington have shown the possibility of using DNA-based electromechanical switches for nanoscale computing.

DNA is considered to be the molecule of life, and researchers have shown considerable interest in utilizing DNA as a nanoscale material in various applications.

A Dec. 14, 2015 UC Davis news release on EurekAlert, which originated the news item, provides more detail,

In their paper published in Nature Communications, the team demonstrated that changing the structure of the DNA double helix by modifying its environment allows the conductance (the ease with which an electric current passes) to be reversibly controlled. This ability to structurally modulate the charge transport properties may enable the design of unique nanodevices based on DNA. These devices would operate using a completely different paradigm than today’s conventional electronics.

“As electronics get smaller they are becoming more difficult and expensive to manufacture, but DNA-based devices could be designed from the bottom-up using directed self-assembly techniques such as ‘DNA origami’,” said Josh Hihath, assistant professor of electrical and computer engineering at UC Davis and senior author on the paper. DNA origami is the folding of DNA to create two- and three-dimensional shapes at the nanoscale level.

“Considerable progress has been made in understanding DNA’s mechanical, structural, and self-assembly properties and the use of these properties to design structures at the nanoscale. The electrical properties, however, have generally been difficult to control,” said Hihath.

New Twist on DNA? Possible Paradigms for Computing

In addition to potential advantages in fabrication at the nanoscale level, such DNA-based devices may also improve the energy efficiency of electronic circuits. The size of devices has been significantly reduced over the last 40 years, but as the size has decreased, the power density on-chip has increased. Scientists and engineers have been exploring novel solutions to improve the efficiency.

“There’s no reason that computation must be done with traditional transistors. Early computers were fully mechanical and later worked on relays and vacuum tubes,” said Hihath. “Moving to an electromechanical platform may eventually allow us to improve the energy efficiency of electronic devices at the nanoscale.”

This work demonstrates that DNA is capable of operating as an electromechanical switch and could lead to new paradigms for computing.

To develop DNA into a reversible switch, the scientists focused on switching between two stable conformations of DNA, known as the A-form and the B-form. In DNA, the B-form is the conventional DNA duplex that is commonly associated with these molecules. The A-form is a more compact version with different spacing and tilting between the base pairs. Exposure to ethanol forces the DNA into the A-form conformation resulting in an increased conductance. Similarly, by removing the ethanol, the DNA can switch back to the B-form and return to its original reduced conductance value.

One Step Toward Molecular Computing

In order to develop this finding into a technologically viable platform for electronics, the authors also noted that there is still a great deal of work to be done. Although this discovery provides a proof-of-principle demonstration of electromechanical switching in DNA, there are generally two major hurdles yet to be overcome in the field of molecular electronics. First, billions of active molecular devices must be integrated into the same circuit as is done currently in conventional electronics. Next, scientists must be able to gate specific devices individually in such a large system.

“Eventually, the environmental gating aspect of this work will have to be replaced with a mechanical or electrical signal in order to locally address a single device,” noted Hihath.

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

Conformational gating of DNA conductance by Juan Manuel Artés, Yuanhui Li, Jianqing Qi, M. P. Anantram, & Joshua Hihath. Nature Communications 6, Article number: 8870 doi:10.1038/ncomms9870 Published 09 December 2015

This paper is open access.