Tag Archives: Singapore

Self-healing supercapacitors from Singapore

Michael Berger has written up the latest and greatest regarding self-healing capacitors and carbon nanotubes (which could have more relevance to your life than you realize) in a March 10, 2014 Nanowerk Spotlight article,

If you ever had problems with the (non-removable) battery in your iPhone or iPad then you well know that the energy storage or power source is a key component in a tightly integrated electronic device. Any damage to the power source will usually result in the breakdown of the entire device, generating at best inconvenience and cost and in the worst case a safety hazard and your latest contribution to the mountains of electronic waste.

A solution to this problem might now be at hand thanks to researchers in Singapore who have successfully fabricated the first mechanically and electrically self-healing supercapacitor.

Reporting their findings in Advanced Materials (“A Mechanically and Electrically Self-Healing Supercapacitor”) a team led by Xiaodong Chen, an associate professor in the School of Materials Science & Engineering at Nanyang Technological University, have designed and fabricated the first integrated, mechanically and electrically self-healing supercapacitor by spreading functionalized single-walled carbon nanotube (SWCNT) films on self-healing substrates.

Inspired by the biological systems’ intrinsic self-repairing ability, a class of artificial ‘smart’ materials, called self-healing materials, which can repair internal or external damages have been developed over the past decade …

Berger goes on to describe how the researchers addressed the issue of restoring electrical conductivity, as well as, restoring mechanical properties to self-healing materials meant to be used as supercapacitors.

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

A Mechanically and Electrically Self-Healing Supercapacitor by Hua Wang, Bowen Zhu, Wencao Jiang, Yun Yang, Wan Ru Leow, Hong Wang, & Xiaodong Chen. Advanced Materials Article first published online: 19 FEB 2014 DOI: 10.1002/adma.201305682

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

Xiaodong Chen and his team were last mentioned here in a Jan. 9, 2014 posting in connection with their work on memristive nanodevices derived from protein.

Nanopolis and China’s Showroon for Nanotechnology

Courtesy: HENN [Architects] [downloaded from http://www.henn.com/en/projects/culture/nanopolis-showroom]

Courtesy: Henn Architects [downloaded from http://www.henn.com/en/projects/culture/nanopolis-showroom]

Marija Bojovic’s Jan. 17, 2014 article for evolo.us offers the preceding image and more in an ar6ticle where she describes the building (Note: Links have been removed),

The layout of the curved building follows the classical inner courtyard typology and its form makes reference to the interplay of three ellipses. The largest ellipse defines the external size of the building, the smallest, the inner courtyard and the middle, the roof edge. At the lowest point, the pronounced slope of the annular allows a second access across the inner courtyard and opens the building to the forecourt opposite and the city. At the same time, the building rises from this point and terminates in the glass facade, which extends over the full height of the building and faces toward the water-scape.

The Showroom for Nanotechnology is part of a larger complex called Nanopollis, which in turn is part of an industrial park, in the city of Suzhou, China. The Nanopolis complex is expected to be opened in 2015. Here’s more about the project according to the agency which is responsible for it (from the Suzhou Nanotechnology webpage on the the Nanopolis website),

Founded in September 2010 as a state-owned company of Suzhou Industrial Park, Suzhou Nanotech focuses on nanotech industry promotion and service to establish an ecosystem for nanotech innovation and commercialization. The company actively works on recruitment and cooperation with industry and innovation resources, R&D facilities and platforms set-up and operation, investment and incubation, marketing and supporting services as well as the construction of “Nanopolis Suzhou”. Nowadays we have two wholly-owned subsidiaries named as Suzhou Nano Venture Capital Co.,Ltd. and SIP Nanotechnology Industry Institute Co., Ltd.

6 main Functions

• Nanopolis construction and operation
• Industry & innovation introduction and cooperation
• Nanotech industry cluster development
• Public platform construction and operation
• Investment and incubation
• Industry promotion & brand establishment

I did find two slides (PDF) describing the project in more detail on the Netherlands Enterprise Agency website,

The SIP [Singapore jointly developed Suzhou Industrial Park] has committed 10 billion RMB (about 1.5 BUSD) for the next five years to further develop Suzhou high-tech industries including nanotech enabled industries. Today the SIP is housed with 20000 national and multinational companies including 3M, Samsung, Siemens, Johnson & Johnson, Phillips, AMD, Bosch, Eli Lily and others within 288 square kilometers. Suzhou was ranked top 3 in “2010 China’s Most Innovative Cities” by Forbes.

… Suzhou intends to attract over 200 nanotech companies from all over the world and 10,000 nanotech experts within the next 5 years to make Suzhou the most global and innovative nanotech hub in China by 2015.

I look forward to hearing more about Nanopolis when it opens. In the meantime, here’s what the architects have to say about their approach to the project (from the HENN Nanopolis webpage),

Suzhou has set itself the target of closing the gap on the world’s leaders as a research and development location. Alongside the Biobay biotechnology park in the west of the city, Nanotech City marks another key element in that strategy. The program includes a total of 1.3 million square metres of floor area.

The creative leitmotif of the design is the relationship of scale between the molecular world, man and urban space. All elements of urban, architectural and landscape design range in density, size and height from the very large to the very small. The fractal logic of the division into units of diminishing size continues from the urban scale down to the facades, where elements of local architecture are reflected in aspects such as colour and structure.

As for HENN, here’s a little more about the company from the company’s About Us webpage,

HENN is an international architectural consultancy with 65 years of expertise in the design and realisation of buildings, masterplans and interior spaces in the fields of culture, administration, teaching and research, development and production as well as urban design.

The office is led by Gunter Henn and eleven partners with offices in Munich, Berlin, Beijing and Shanghai. 350 employees from 25 countries are able to draw upon a wealth of knowledge collected over three generations of building experience in addition to a worldwide network of partners and experts in a variety of disciplines.

 

*2700th posting: new generation of hybird memristive nanodevices and an update of HP labs and its memristive products

Hard to believe this is the *2700th posting but yay! To commemorate this special occasion I’m featuring two items about memristors, work on protein-based memristors and an update of my Feb. 7, 2013 posting on the HP Labs and its promises of memristor-based products.

Michael Berger’s Dec. 16, 2013 issue of Nanowerk Spotlight focused on memristor research from bioengineers at Singapore’s Nanyang Technological University (Note: Links have been removed),

 Based on the rapid development of synthetic chemistry and bioengineering, researchers have begun to build hybrid nanostructures with various biomolecules to fulfill the functional requirements of advanced nanocircuits. Proteins already perform functions such as signalling, charge transport or storage, in all biochemical processes.

“Although the diversity of these natural molecules is vast – for instance, more than a million variants of an individual protein may be created via genetic engineering – tailoring their structures to fit the variable and complex requirements of both the biological and non-biological world is achievable by leveraging on the rapidly developing bioengineering field,” Xiaodong Chen, an Associate Professor in the School of Materials Science & Engineering at Nanyang Technological University, tells Nanowerk. “On a parallel note, bioengineering may provide an alternative approach to tune the structural and electronic properties of functional molecules leading to further development in the field of molecular electronics.”

Berger provides more context on this work by way of a 2011 Spotlight about the research (featured in my Sept. 19, 2011 posting) and then describes Chen’s latest work,

In new work, reported in a recent edition of Small (“Bioengineered Tunable Memristor Based on Protein Nanocage”) Chen and his team demonstrate a strategy for the fabrication of memristive nanodevices with stable and tunable performance by assembling ferritin monolayer inside a on-wire lithography-generated ∼12 nm gap.

Whereas the protein-based memristor devices in the previous work were fabricated from the commercial horse spleen ferritin, the new work uses the unique high iron loading capacity of Archaeoglobus fulgidus ferritin (AfFtn).

“We hypothesized that if the composition of this iron complex core can be modulated, the switching performance of the protein-based device can be controlled accordingly,” says Chen.

They found that the (tunable) iron loading in the AfFtn nanocages drastically impacts the performance of the memristive devices. The higher iron loading amount contributes to better memristive performance due to higher electrochemical activity of the ferric complex core.

This work is not going to be found in any applications for molecular devices at any time soon but it seems promising at this stage. For those who’d like more information, there’s Berger’s article or this link and a citation to the researchers’ paper,

Bioengineered Tunable Memristor Based on Protein Nanocage by Fanben Meng, Barindra Sana, Yuangang Li, Yuanjun Liu, Sierin Lim, & Xiaodong Chen. Article first published online: 19 AUG 2013 DOI: 10.1002/smll.201300810
© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

This paper is behind a paywall but Wiley does offer a number of viewing options at different price points.

HP Labs and its memristor-based products

Following on last year’s Feb. 7, 2013 update (scroll down about 1/2 way), it seems like another annual update is in order unfortunately, the news seems like a retread. Memristor’-based devices from HP Labs will not be launched (in the marketplace or even to show at technology shows) this year either. In fact, any sort of launch is much further in the future according to Chris Mellor’s Nov. 1, 2013 article for The Register; Note: Links have been removed),

HP has warned El Reg not to get its hopes up too high after the tech titan’s CTO Martin Fink suggested StoreServ arrays could be packed with 100TB Memristor drives come 2018.

In five years, according to Fink, DRAM and NAND scaling will hit a wall, limiting the maximum capacity of the technologies: process shrinks will come to a shuddering halt when the memories’ reliability drops off a cliff as a side effect of reducing the size of electronics on the silicon dies.

The HP answer to this scaling wall is Memristor, its flavour of resistive RAM technology that is supposed to have DRAM-like speed and better-than-NAND storage density. Fink claimed at an HP Discover event in Las Vegas that Memristor devices will be ready by the time flash NAND hits its limit in five years. He also showed off a Memristor wafer, adding that it could have a 1.5PB capacity by the end of the decade.

Fink spoke about the tech in June, but this week a HP spokesperson clarified to The Reg:

As with many other ground-breaking technologies being developed at HP Labs, HP has not yet committed to a specific product roadmap for Memristor-based products. HP does have internal milestones that are subject to change, depending on shifting market, technology and business conditions.

Every time I read about it HP Labs’ memristor-based products  they keep receding further into the future. Compare this latest announcement with what was being said at the time of my Feb.7, 2013 posting,

… Stanley Williams’ presence in the video reminded me of the memristor and an announcement (mentioned in my April 19, 2012 posting) that HP Labs would be rolling out some memristor-enabled products in 2013. Sadly, later in the year I missed this announcement, from a July 9, 2012 posting by Chris Mellor for TheRegister.co.uk,

Previously he (Stanley Williams) has said that HP and fab partner Hynix would launch a memristor product in the summer of 2013. At the Kavli do [Kavli Foundation Roundtable, June 2012], Williams said: “In terms of commercialisation, we’ll have something technologically viable by the end of next year [2014].”

To be fair, it seems HP Labs had abandoned plans for a commercial launch of memristor-based products even in 2013 but now it seems there is no roadmap of any kind.

* Corrected from ’3000′ to ’2700′.

Nanoimprint Foundry in Singapore

Sept. 30, 2013 marks the date for the launch of Singapore’s Nanoimprint Foundry. From the Sept. 30, 2013 news item on Nanowerk,

A*STAR’s [Agency for Science, Technology and Research] Institute of Materials Research and Engineering (IMRE) and its partners launched a new Nanoimprint Foundry that will develop, test-bed and prototype specially engineered plastics and surfaces for the specific purpose of commercialising the technologies. Possible applications of nanoimprint technology include dry adhesives, aesthetic packaging, contact lenses, biomedical cell scaffolds, anti-frost surfaces and anti-bacteria materials.

The multi-party investment will bring together national research organisations, suppliers and manufacturers spanning the nanotechnology value chain, and government agencies to promote the technology. The Foundry is part of a masterplan spearheaded by A*STAR to push translational research and accelerate commercialisation of home-grown technologies. In partnership with other A*STAR research institutes, IMRE will work with companies like Toshiba Machines Co Ltd, EV Group, NTT Advanced Technology Corporation, NIL Technology ApS, Kyodo International Inc., micro resist technology GmbH, Nanoveu Pte Ltd and Solves Innovative Technology Pte Ltd to produce prototypes for real-world products and applications. The Foundry and its partners will also work closely with Singapore’s Economic Development Board (EDB) and SPRING to promote its nanoimprint applications to industry as part of the plans to build up Singapore’s high-value manufacturing capabilities.

The Sept. 30, 2013 A*STAR press release, which originated the news item, itemizes the various news points of interest,

3.     “We can help companies develop up to 20,000 samples for proof-of-concept and pilot production allowing manufacturers to shorten the product cycle but minus the heavy capital R&D investment”, said Dr Karen Chong, the IMRE scientist who is heading the Foundry. Dr Chong added that the Foundry will be a one-stop shop for companies seeking to conceive, design and develop solutions for new, revolutionary products based on the versatile nanoimprint technology.

4.     “The Foundry gives us the tools for creating real products that target industry end users and ultimately consumers”, explained Mr Masayuki Yagi, Director & General Manager, Advanced Machinery Business Unit, Toshiba Machines Co Ltd, Japan on why the company chose to participate in the initiative. “Toshiba Machines and the Foundry will aim to deliver innovative engineering solutions based on nanoimprint and be the best partner for leading industries”.

5.     According to Mr Koh Teng Kwee, Director of Solves Innovative Technology Pte Ltd, “Working with IMRE since IICON 1[1] am sure IMRE’s nanoimprint technology and know-how is now ready for industrial adoption.  In my opinion, IMRE is able to provide everything needed for a new product realisation involving nanoimprinting.”

6.     “There is a billion-dollar, virtually untapped market for new advanced nanotechnology products that can make use of what the Foundry has to offer”, said Prof Andy Hor, Executive Director for IMRE, adding that the initiative will hasten the industrialisation of nanoimprinting in this lucrative market segment. In consumer care for example, the global market for contact lenses – where nanoimprint technology can be used to produce new functionalities like multi-coloured lenses – is expected to grow to USD 11.7 billion by 2015[2].

7.     “The Foundry is the first one-stop shop to pull different value chain partners together to offer solutions based on nanoimprint through equipment, moulds, materials and applications to end user companies”, said Dr Tan Geok Leng, Executive Director of A*STAR’s Science and Engineering Research Council which oversees a number of the research institutes dedicated to the physical sciences and engineering. “The new Foundry is part of Singapore’s strategy to create a new, advanced high-value manufacturing sector to support its growing knowledge-based economy.”

8.     “As part of EDB’s vision to position Singapore as an Advanced Manufacturing Hub, we will continue to work with companies to co-create and adopt advanced manufacturing technologies. We see this new Research Foundry as one of the key infrastructures to strengthen nanoscale-manufacturing capabilities in Singapore”, said Mr Yi-Hsen Gian, Director (i3), Economic Development Board (EDB), Singapore.

[1]Source: Industrial Consortium On Nanoimprint, Project 1 on anti-reflection surfaces

[2] Source: Global Industry Analysts, Inc.

Good luck with the foundry and this attempt to set up a manufacturing process!

Assembly-line 3-D tissue engineering

It looks as if the researchers at Singapore’s Institute of Bioengineering and Nanotechnology (IBN), have developed a template for producing complex tissues such as those in liver and in fat, from an Aug. 20, 2013 news item on ScienceDaily,

Researchers at the Institute of Bioengineering and Nanotechnology (IBN) have developed a simple method of organizing cells and their microenvironments in hydrogel fibers. Their unique technology provides a feasible template for assembling complex structures, such as liver and fat tissues, as described in their recent publication in Nature Communications.

According to IBN Executive Director Professor Jackie Y. Ying, “Our tissue engineering approach gives researchers great control and flexibility over the arrangement of individual cell types, making it possible to engineer prevascularized tissue constructs easily. This innovation brings us a step closer toward developing viable tissue or organ replacements.”

The Aug. 19, 2013 A*STAR’s (Singapore’s Agency for Science and Technology Research) IBN  press release, which originated the news item, offers a detailed explanation of how this discovery could make tissue and organ replacements much easier,

IBN Team Leader and Principal Research Scientist, Dr Andrew Wan, elaborated, “Critical to the success of an implant is its ability to rapidly integrate with the patient’s circulatory system. This is essential for the survival of cells within the implant, as it would ensure timely access to oxygen and essential nutrients, as well as the removal of metabolic waste products. Integration would also facilitate signaling between the cells and blood vessels, which is important for tissue development.”

Tissues designed with pre-formed vascular networks are known to promote rapid vascular integration with the host. Generally, prevascularization has been achieved by seeding or encapsulating endothelial cells, which line the interior surfaces of blood vessels, with other cell types. In many of these approaches, the eventual distribution of vessels within a thick structure is reliant on in vitro cellular infiltration and self-organization of the cell mixture. These are slow processes, often leading to a non-uniform network of vessels within the tissue. As vascular self-assembly requires a large concentration of endothelial cells, this method also severely restricts the number of other cells that may be co-cultured.

Alternatively, scientists have attempted to direct the distribution of newly formed vessels via three-dimensional (3D) co-patterning of endothelial cells with other cell types in a hydrogel. This approach allows large concentrations of endothelial cells to be positioned in specific regions within the tissue, leaving the rest of the construct available for other cell types. The hydrogel also acts as a reservoir of nutrients for the encapsulated cells. However, co-patterning multiple cell types within a hydrogel is not easy. Conventional techniques, such as micromolding and organ printing, are limited by slow cell assembly, large volumes of cell suspension, complicated multi-step processes and expensive instruments. These factors also make it difficult to scale up the production of implantable 3D cell-patterned constructs. To date, these approaches have been unsuccessful in achieving vascularization and mass transport through thick engineered tissues.

To overcome these limitations, IBN researchers have used interfacial polyelectrolyte complexation (IPC) fiber assembly, a unique cell patterning technology patented by IBN, to produce cell-laden hydrogel fibers under aqueous conditions at room temperature. Unlike other methods, IBN’s novel technique allows researchers to incorporate different cell types separately into different fibers, and these cell-laden fibers may then be assembled into more complex constructs with hierarchical tissue structures. In addition, IBN researchers are able to tailor the microenvironment for each cell type for optimal functionality by incorporating the appropriate factors, e.g. proteins, into the fibers. Using IPC fiber assembly, the researchers have engineered an endothelial vessel network, as well as cell-patterned fat and liver tissue constructs, which have successfully integrated with the host circulatory system in a mouse model and produced vascularized tissues.

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

Patterned prevascularised tissue constructs by assembly of polyelectrolyte hydrogel fibres by Meng Fatt Leong,    Jerry K. C. Toh, Chan Du, Karthikeyan Narayanan, Hong Fang Lu, Tze Chiun Lim, Andrew C. A. Wan, & Jackie Y. Ying. Nature Communications 4, Article number: 2353 doi:10.1038/ncomms3353 Published 19 August 2013

This article is behind a paywall although you can preview it with ReadingCube access.

Alberta’s (Canada) science education gets shout-out from UK’s (United Kingdom) Parliamentary Under Secretary of State for Education, Elizabeth Truss

On July 11, 2013 Elizabeth Truss, UK Parliamentary Under Secretary of State for Education (H/T Nassif Ghoussoub’s Piece of Mind), spoke at an International Student Science Fair and cited Alberta’s science education and high performance, along with Singapore’s, in her speech,

So at primary, we want children to get a really solid foundation in the basics of scientific knowledge and language, backed up by more and higher quality practical work and experiments – building on the approaches to science education in high-performing jurisdictions like Singapore and Alberta.

Obviously, Truss is making a case for science and technology education as preparation for the future in a speech that amongst other things emphasizes “non-artificial intelligence,”

As the future comes hurtling towards us, the most important resource any country can boast is not physical, nor technological – but human.

Every leap forward, every flash of insight, relies not on infrastructure, capital or regulatory regimes – important as they are.

But on people. On their brains, their knowledge and their determination to succeed.

On the schoolchildren and students of today – the innovators of tomorrow.

We don’t know yet precisely what skills will be needed in the future.

But as technology transforms the working world – and jobs polarise between the low-skilled and the very high-skilled, highly-educated – we know that the value of high-level skills is growing.

The 21st century will need people who are equally comfortable manipulating numbers, words and lines of computer code; who have the skills and the knowledge to understand both foreign languages and mathematical equations. Rounded individuals who can analyse and think logically, who have mastered both arts and sciences.

Never mind Bitcoin, education is the currency of the future.

International evidence has proved that countries with successful education systems grow more quickly.

Given Truss is speaking at an International Student(s) Science Fair (this is the only site [ ISSF 2012] that seemed to fit the description), it does seem like she’s speaking to the ‘converted’. Students at an international science fair have shown a fair degree of interest and commitment and this speech while inspiring doesn’t address one of the major problems described in a rather interesting UK research project on children’s science attitudes. From my Jan. 31, 2012 posting,

One of the research efforts in the UK is the ASPIRES research project at King’s College London (KCL), which is examining children’s attitudes to science and future careers. Their latest report, Ten Science Facts and Fictions: the case for early education about STEM careers (PDF), is profiled in a Jan. 11, 2012 news item on physorg.com (from the news item),

Professor Archer [Louise Archer, Professor of Sociology of Education at King’s] said: “Children and their parents hold quite complex views of science and scientists and at age 10 or 11 these views are largely positive. The vast majority of children at this age enjoy science at school, have parents who are supportive of them studying science and even undertake science-related activities in their spare time. They associate scientists with important work, such as finding medical cures, and with work that is well paid.

“Nevertheless, less than 17 per cent aspire to a career in science. These positive impressions seem to lead to the perception that science offers only a very limited range of careers, for example doctor, scientist or science teacher. It appears that this positive stereotype is also problematic in that it can lead people to view science as out of reach for many, only for exceptional or clever people, and ‘not for me’.

Professor Archer says the findings indicate that engaging young people in science is not therefore simply a case of making it more interesting or more fun. She said: “There is a disconnect between interest and aspirations. Our research shows that young people’s ambitions are strongly influenced by their social backgrounds – ethnicity, social class and gender – and by family contexts. [emphases mine]

In that 2012 posting, I also featured a US project where researchers developed an intervention for stimulating more adolescent interest in science and technology studies by focusing on the adolescent students’ parents.

Both the UK’s ASPIRES project and the US project suggest getting children to pursue education and careers in STEM (science, technology, engineering, and mathematics) fields has more to do with family and social culture than is often recognized.

Adding a somewhat ironic wrinkle to this discussion is a finding from a study by the Brookings Metropolitan Policy program that 20% of all jobs in the US—not 4%-5% of jobs as claimed by the US National Science Foundation—could be described as STEM jobs. From the June 10, 2013 article for Fast Company by Ariel Schwartz,

…, STEM jobs aren’t limited to workers with advanced degrees–50% don’t even require a bachelor’s degree. Many of the more blue-collar STEM jobs are in fields like construction, plant and system operation, and repair (telecommunications equipment, aircraft, computer, office machine, etc.).

The irony is that family members who think that science careers are for other ‘smart and exceptional’ people may themselves have a STEM-based job/career. You can find the Brookings Institute report here. It should be noted this report The Hidden STEM Economy) has a unique definition of STEM, from the Schwartz article,

The Institute explains in a press release: “Previous studies classified workers as STEM only if they worked in a small number of professional occupations, but the Brookings definition classifies occupations according to the level of knowledge in STEM fields that workers need to perform their jobs. As a result, many nonprofessional jobs in manufacturing, health care, construction, and mining industries could be considered STEM jobs.”

Take for example, car mechanics. Today’s mechanics need to know about computers and fairly complex electronics, such as lithium-ion batteries, in addition to standard mechanics. (BTW, In the late 1980s, I had a coop student job at a school board where even then they trying to integrate electronics and information technology into their trades education programmes.)

If you have the time, I do recommend reading Truss’s speech (by following either the link to Nassif’s website or the direct link to the speech) and/or Schwartz’s article.

Fish gets invisibility cloak first, cat waits patiently

An invisibility cloak devised by researchers in Singapore and China is receiving a high degree of interest online with a June 14, 2013 news item on Nanowerk, a June 11, 2013 article by Philip Ball for Nature, and a June 13, 2013 article by Sarah Gates for Huffington Post.

The research paper, Natural Light Cloaking for Aquatic and Terrestrial Creatures by Hongsheng Chen, Bin Zheng, Lian Shen, Huaping Wang, Xianmin Zhang, Nikolay Zheludev, Baile Zhang was submitted June 7, 2013 to arXiv.org (arXiv is an e-print service in the fields of physics, mathematics, computer science, quantitative biology, quantitative finance and statistics. Submissions to arXiv must conform to Cornell University academic standards. arXiv is owned and operated by Cornell University, a private not-for-profit educational institution),

A cloak that can hide living creatures from sight is a common feature of mythology but still remains unrealized as a practical device. To preserve the phase of wave, the previous cloaking solution proposed by Pendry \emph{et al.} required transforming electromagnetic space around the hidden object in such a way that the rays bending around it have to travel much faster than those passing it by. The difficult phase preservation requirement is the main obstacle for building a broadband polarization insensitive cloak for large objects. Here, we suggest a simplifying version of Pendry’s cloak by abolishing the requirement for phase preservation as irrelevant for observation in incoherent natural light with human eyes that are phase and polarization insensitive. This allows the cloak design to be made in large scale using commonly available materials and we successfully report cloaking living creatures, a cat and a fish, in front of human eyes.

What they seem to be saying is that it’s possible to create an invisibility cloak perceptible to the human eye that is made of everyday materials.

I’ll show the fish video first. Pay attention as that fish darts behind its invisibility cloak almost as soon as the video starts (from the Nanowerk Youbube channel; June 14, 2013 Nanowerk news item),

Then, there’s the cat (also from the Nanowerk Youtube channel),


The June 11, 2013 article by Philip Ball for Nature describes the device which provides invisibility,

… This latest addition to the science of invisibility cloaks is one of the simplest implementations so far, but there’s no denying its striking impact.

The ‘box of invisibility’ has been designed by a team of researchers at Zhejiang University in Hangzhou, China, led by Hongsheng Chen, and their coworkers. The box is basically a set of prisms made from high-quality optical glass that bend light around any object in the enclosure around which the prisms are arrayed, the researchers describe in a paper posted on the online repository arXiv.

Ball suggests that this latest invisibility cloak is very similar to a Victorian era music hall trick,

As such, the trick is arguably closer to ‘disappearances’ staged in Victorian music hall using arrangements of slanted mirrors than to the modern use of substances called metamaterials to achieve invisibility by guiding light rays in unnatural ways.

As far as I know, the ‘metamaterial’ invisibility cloaks require very sophisticated equipment for their production, are incredibly expensive, and aren’t all that practical.

Gates’s June 13, 2013 article for the Huffington Post provides an overview of some of the recent work on invisibility cloaks and metamaterials, as well as, previous work done by Dr. Hongsheng Chen, an electromagnetics professor at Zhejiang University (China), and Baile Zhang, an assistant physics professor at Singapore’s Nanyang Technological University before they unveiled this latest invisibility cloak.

My most recent posting on the topic was a June 6, 2013 piece on a temporal invisibility cloak.

Beautiful color printing for encoding high density data

Researchers at A*STAR (Agency for Science Technology and Research) based in Singapore have printed images at an extraordinary resolution of 100,000 dots per inch according to an Apr. 10, 2013 news item on ScienceDaily,

To print the image, the team coated a silicon wafer with insulating hydrogen silsesquioxane and then removed part of that layer to leave behind a series of upright posts of about 95 nanometers high. They capped these nanoposts with layers of chromium, silver and gold (1, 15 and 5 nanometers thick, respectively), and also coated the wafer with metal to act as a backreflector.

Each color pixel in the image contained four posts at most, arranged in a square. The researchers were able to produce a rainbow of colors simply by varying the spacing and diameter of the posts to between 50 nanometers and 140 nanometers.

When light hits the thin metal layer that caps the posts, it sends ripples — known as plasmons — running through the electrons in the metal. The size of the post determines which wavelengths of light are absorbed, and which are reflected …

Although the current process is not practical, it takes several hours to print an image there are some intriguing benefits,

Printing images in this way makes them potentially more durable than those created with conventional dyes. In addition, color images cannot be any more detailed: two adjacent dots blur into one if they are closer than half the wavelength of the light reflecting from them. Since the wavelength of visible light ranges about 380-780 nanometers, the nanoposts are as close as is physically possible to produce a reasonable range of colors.

The researchers believe there may be applications for anti-counterfeiting tags and encoding high density data.

You can read more about the work and find a citation and link to the researchers’ study published in Nature Nanotechnology at the ScienceDaily news item.

Astonishing material, multi-use titanium dioxide nanofibres

The enthusiasm in the Mar. 20, 2013 news release on EurekAlert about Darren Sun’s work with titanium dioxide nanofibres seems boundless,

A new wonder material that can generate hydrogen, produce clean water and even create energy.

Science fiction? Hardly, and there’s more – It can also desalinate water, be used as flexible water filtration membranes, help recover energy from desalination waste brine, be made into flexible solar cells and can also double the lifespan of lithium ion batteries. With its superior bacteria-killing capabilities, it can also be used to develop a new type of antibacterial bandage.

Scientists at Nanyang Technological University (NTU) in Singapore, led by Associate Professor Darren Sun have succeeded in developing a single, revolutionary nanomaterial that can do all the above and at very low cost compared to existing technology.

The Nanyang Technological University Mar. 20, 2013 news release (also posted to EurekAlert) gives details about how Sun created his ‘wonder’ material,

This breakthrough which has taken Prof Sun five years to develop is dubbed the Multi-use Titanium Dioxide (TiO2). It is formed by turning titanium dioxide crystals into patented nanofibres, which can then be easily fabricated into patented flexible filter membranes which include a combination of carbon, copper, zinc or tin, depending on the specific end product needed.

Titanium dioxide is a cheap and abundant material, which has been scientifically proven to have the ability to accelerate a chemical reaction (photocatalytic) and is also able to bond easily with water (hydrophilic).

Prof Sun, 52, from NTU’s School of Civil and Environmental Engineering, said such a low-cost and easily produced nanomaterial is expected to have immense potential to help tackle ongoing global challenges in energy and environmental issues.

With the world’s population expected to hit 8.3 billion by 2030, there will be a massive increase in the global demand for energy and food by 50 per cent and 30 per cent for drinking water (Population Institute report, titled 2030: The “Perfect Storm” Scenario).

“While there is no single silver bullet to solving two of the world’s biggest challenges: cheap renewable energy and an abundant supply of clean water; our single multi-use membrane comes close, with its titanium dioxide nanoparticles being a key catalyst in discovering such solutions,” Prof Sun said. “With our unique nanomaterial, we hope to be able to help convert today’s waste into tomorrow’s resources, such as clean water and energy.”

Prof Sun had initially used titanium dioxide with iron oxide to make anti-bacterial water filtration membranes to solve biofouling – bacterial growth which clogs up the pores of membranes, obstructing water flow.

While developing the membrane, Prof Sun’s team also discovered that it could act as a photocatalyst, turning wastewater into hydrogen and oxygen under sunlight while still producing clean water. Such a water-splitting effect is usually caused by Platinum, a precious metal that is both expensive and rare.

Here’s a list of what the researchers are claiming multi-use titanium dioxide materials can accomplish, from the news release,

Producing hydrogen and clean water

This discovery, which was published recently in the academic journal, Water Research, showed that a small amount of nanomaterial (0.5 grams of titanium dioxide nanofibres treated with copper oxide), can generate 1.53 millilitre of hydrogen in an hour when immersed in one litre of wastewater. This amount of hydrogen produced is three times more than when Platinum is used in the same situation.

Depending on the type of wastewater, the amount of hydrogen generated can be as much as 200 millilitres in an hour. Also to increase hydrogen production, more nanomaterial can be used in larger amounts of wastewater.

Producing low-cost flexible forward osmosis membranes

Not only can titanium dioxide particles help split water, it can also make water filter membranes hydrophilic – allowing water to flow through it easily, while rejecting foreign contaminants, including those of salt, making it perfect for desalinating water using forward osmosis. Thus a new super high flux (flow rate) forward osmosis membrane is developed.

This discovery was published recently in last month’s journal of Energy and Environmental Science. This is the first such report of TiO2 nanofibres and particles used in forward osmosis membrane system for clean water production and energy generation.

Producing new antibacterial bandages

With its anti-microbial properties and low cost, the membrane can also be used to make breathable anti-bacterial bandages, which would not only prevent infections and tackle infection at open wounds, but also promote healing by allowing oxygen to permeate through the plaster.

The membrane’s material properties are also similar to polymers used to make plastic bandages currently sold on the market.

Producing low-cost flexible solar cells

Prof Sun’s research projects have shown out that when treated with other materials or made into another form such as crystals, titanium dioxide can have other uses, such as in solar cells.

By making a black titanium dioxide polycrystalline sheet, Prof Sun’s team was able to make a flexible solar-cell which can generate electricity from the sun’s rays.

Producing longer lasting lithium ion batteries

Concurrently, Prof Sun has another team working on developing the black titanium dioxide nanomaterial to be used in Lithium ion batteries commonly used in electronic devices.

Preliminary results from thin coin-like lithium ion batteries, have shown that when titanium dioxide sphere-like nanoparticles modified with carbon are used as the anode (negative pole), it can double the capacity of the battery. This gives such batteries a much longer lifespan before it is fully drained. The results were featured prominently in a highly respected Journal of Materials Chemistry on its cover page last year.

As is expected these days, from the news release,

Next step – commercialisation

Prof Sun and his team of 20, which includes 6 undergraduates, 10 PhD students and 4 researchers, are now working to further develop the material while concurrently spinning off a start-up company to commercialise the product.

They are also looking to collaborate with commercial partners to speed up the commercialisation process.

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

Novel-Structured Electrospun TiO2/CuO Composite Nanofibers for High Efficient Photocatalytic Cogeneration of Clean Water and Energy from Dye Wastewater by Siew Siang Lee, Hongwei Bai Zhaoyang Liu, & Darren Delai Sun. Water Research Available online 19 March 2013 In Press, Accepted Manuscript http://dx.doi.org/10.1016/j.watres.2012.12.044

This paper is behind a paywall. Good luck to Professor Sun and his colleagues.

Make your carbon atoms stand taller to improve electronic devices

Scientists from Ireland ((Tyndall National Institute at University College Cork [UCC]) and Singapore (National University of Singapore [NUS]) have jointly published a paper about how they achieved a ten-fold increase in the switching efficiency of electronic devices by changing one carbon atom. From the Jan. 21, 2013 news item on ScienceDaily,

These devices could provide new ways to combat overheating in mobile phones and laptops, and could also aid in electrical stimulation of tissue repair for wound healing.

The breakthrough creation of molecular devices with highly controllable electrical properties will appear in the February [2013] issue of Nature Nanotechnology. Dr. Damien Thompson at the Tyndall National Institute, UCC and a team of researchers at the National University of Singapore led by Prof. Chris Nijhuis designed and created the devices, which are based on molecules acting as electrical valves, or diode rectifiers.

Dr. Thompson explains, “These molecules are very useful because they allow current to flow through them when switched ON and block current flow when switched OFF. The results of the study show that simply adding one extra carbon is sufficient to improve the device performance by more than a factor of ten. We are following up lots of new ideas based on these results, and we hope ultimately to create a range of new components for electronic devices.” Dr. Thompson’s atom-level computer simulations showed how molecules with an odd number of carbon atoms stand straighter than molecules with an even number of carbon atoms. This allows them to pack together more closely. Tightly-packed assemblies of these molecules were formed on metal electrode surfaces by the Nijhuis group in Singapore and were found to be remarkably free of defects. These high quality devices can suppress leakage currents and so operate efficiently and reliably. The device can be cleanly switched on and off purely on the basis of the charge and shape of the molecules, just like in the biological nanomachines that regulate photosynthesis, cell division and tissue growth.

The Jan. ??, 2013 University College Cork news release, which originated the news item, provides more details,

The combined experiments and simulations show for the first time that minute improvements in molecule orientation and packing trigger changes in van der Waals forces that are sufficiently large to dramatically improve the performance of electronic devices. Dr. Thompson explains: “These van der Waals forces are the weakest of all intermolecular forces and only become significant when summed over large areas. Hence, up until now, the majority of research into ultra-small devices has used stronger “pi-pi” interactions to stick molecules together, and has ignored the much weaker, but ubiquitous, van der Waals interactions. The present study shows how van der Waals effects, which are present in every conceivable molecular scale device, can be tuned to optimise the performance of the device.”

The devices are based on molecules that act as diodes by allowing current to pass through them when operated at forward bias and blocking current when the bias is reversed. Molecular rectifiers were first proposed back in 1974, and advances in scientific computing have allowed molecular‐level design to be used over the past decade to develop new organic materials that provide better electrical responses. However, the relative importance of the interactions between the molecules, the nature of the molecule-metal contact and the influence of environmental effects have been questioned. This new research demonstrates that dramatic improvements in device performance may be achieved by controlling the van der Waals forces that pack the molecules together. Simply changing the number of carbon atoms by one provides significantly more stable and more reproducible devices that exhibit an order of magnitude improvement in ON/OFF ratio. The research findings demonstrate the feasibility of boosting device performances by creating tighter seals between molecules.

Here a citation and a link to the paper,

The role of van der Waals forces in the performance of molecular diodes by Nisachol Nerngchamnong, Li Yuan, Dong-Chen Qi, Jiang Li, Damien Thompson, & Christian A. Nijhuis. Nature Nanotechnology (2013) doi:10.1038/nnano.2012.238 Advance online publication: Jan. 6, 2013.

This paper is behind a paywall.