Tag Archives: US

Boron nitride-graphene hybrid nanostructures could lead to next generation ‘green’ cars

An Oct. 24, 2016 phys.org news item describes research which may lead to improved fuel storage in ‘green’ cars,

Layers of graphene separated by nanotube pillars of boron nitride may be a suitable material to store hydrogen fuel in cars, according to Rice University scientists.

The Department of Energy has set benchmarks for storage materials that would make hydrogen a practical fuel for light-duty vehicles. The Rice lab of materials scientist Rouzbeh Shahsavari determined in a new computational study that pillared boron nitride and graphene could be a candidate.

An Oct. 24, 2016 Rice University news release (also on EurekAlert), which originated the news item, provides more detail (Note: Links have been removed),

Shahsavari’s lab had already determined through computer models how tough and resilient pillared graphene structures would be, and later worked boron nitride nanotubes into the mix to model a unique three-dimensional architecture. (Samples of boron nitride nanotubes seamlessly bonded to graphene have been made.)

Just as pillars in a building make space between floors for people, pillars in boron nitride graphene make space for hydrogen atoms. The challenge is to make them enter and stay in sufficient numbers and exit upon demand.

In their latest molecular dynamics simulations, the researchers found that either pillared graphene or pillared boron nitride graphene would offer abundant surface area (about 2,547 square meters per gram) with good recyclable properties under ambient conditions. Their models showed adding oxygen or lithium to the materials would make them even better at binding hydrogen.

They focused the simulations on four variants: pillared structures of boron nitride or pillared boron nitride graphene doped with either oxygen or lithium. At room temperature and in ambient pressure, oxygen-doped boron nitride graphene proved the best, holding 11.6 percent of its weight in hydrogen (its gravimetric capacity) and about 60 grams per liter (its volumetric capacity); it easily beat competing technologies like porous boron nitride, metal oxide frameworks and carbon nanotubes.

At a chilly -321 degrees Fahrenheit, the material held 14.77 percent of its weight in hydrogen.

The Department of Energy’s current target for economic storage media is the ability to store more than 5.5 percent of its weight and 40 grams per liter in hydrogen under moderate conditions. The ultimate targets are 7.5 weight percent and 70 grams per liter.

Shahsavari said hydrogen atoms adsorbed to the undoped pillared boron nitride graphene, thanks to  weak van der Waals forces. When the material was doped with oxygen, the atoms bonded strongly with the hybrid and created a better surface for incoming hydrogen, which Shahsavari said would likely be delivered under pressure and would exit when pressure is released.

“Adding oxygen to the substrate gives us good bonding because of the nature of the charges and their interactions,” he said. “Oxygen and hydrogen are known to have good chemical affinity.”

He said the polarized nature of the boron nitride where it bonds with the graphene and the electron mobility of the graphene itself make the material highly tunable for applications.

“What we’re looking for is the sweet spot,” Shahsavari said, describing the ideal conditions as a balance between the material’s surface area and weight, as well as the operating temperatures and pressures. “This is only practical through computational modeling, because we can test a lot of variations very quickly. It would take experimentalists months to do what takes us only days.”

He said the structures should be robust enough to easily surpass the Department of Energy requirement that a hydrogen fuel tank be able to withstand 1,500 charge-discharge cycles.

Shayeganfar [Farzaneh Shayeganfar], a former visiting scholar at Rice, is an instructor at Shahid Rajaee Teacher Training University in Tehran, Iran.

 

Caption: Simulations by Rice University scientists show that pillared graphene boron nitride may be a suitable storage medium for hydrogen-powered vehicles. Above, the pink (boron) and blue (nitrogen) pillars serve as spacers for carbon graphene sheets (gray). The researchers showed the material worked best when doped with oxygen atoms (red), which enhanced its ability to adsorb and desorb hydrogen (white). Credit: Lei Tao/Rice University

Caption: Simulations by Rice University scientists show that pillared graphene boron nitride may be a suitable storage medium for hydrogen-powered vehicles. Above, the pink (boron) and blue (nitrogen) pillars serve as spacers for carbon graphene sheets (gray). The researchers showed the material worked best when doped with oxygen atoms (red), which enhanced its ability to adsorb and desorb hydrogen (white). Credit: Lei Tao/Rice University

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

Oxygen and Lithium Doped Hybrid Boron-Nitride/Carbon Networks for Hydrogen Storage by Farzaneh Shayeganfar and Rouzbeh Shahsavari. Langmuir,  DOI: 10.1021/acs.langmuir.6b02997 Publication Date (Web): October 23, 2016

Copyright © 2016 American Chemical Society

This paper is behind a paywall.

I last featured research by Shayeganfar and  Shahsavari on graphene and boron nitride in a Jan. 14, 2016 posting.

Creeping gel does ‘The Loco-Motion’

Now it’s the creeping gel’s turn, from an Oct. 24, 2016 news item on phys.org,

Directed motion seems simple to us, but the coordinated interplay of complex processes is needed, even for seemingly simple crawling motions of worms or snails. By using a gel that periodically swells and shrinks, researchers developed a model for the waves of muscular contraction and relaxation involved in crawling. As reported in the journal Angewandte Chemie, they were able to produce two types of crawling motion by using inhomogeneous irradiation.

 

Courtesy: Angewandte Chemie

Courtesy: Angewandte Chemie

An Oct. 24, 2016 Angewandte Chemie (Wiley) press release (also on EurekAlert), which originated the news item, explains further,

Crawling comes from waves that travel through muscle. These waves can travel in the same direction as the animal is crawling (direct waves), from the tail end toward the head, or in the opposite direction (retrograde waves), from the head toward the tail. While land snails use the former type of wave, earthworms and limpets use the latter. Chitons (polyplacophora) can switch between both types of movement.

With the aid of a chemical model in the form of a self-oscillating gel, researchers working with Qingyu Gao at the China University of Mining and Technology (Jiangsu, China) and Irving R. Epstein at Brandeis University (Waltham, Massachusetts, USA) have been able to answer some of the many questions about these crawling processes.

A gel is a molecular network with liquid bound in the gaps. In this case, the liquid contains all of the ingredients needed for an oscillating chemical reaction (“chemical clock”). The researchers incorporated one component of their reaction system into the network: a ruthenium complex. During the reaction, the ruthenium periodically switches between two oxidation states, Ru2+ and Ru3+. This switch changes the gel so that in one state it can hold more liquid than the other, so the gel swells and shrinks periodically. Like the chemical clock, these regions propagate in waves, similar to the waves of muscle contractions in crawling.

The complex used in this gel also changes oxidation state when irradiated with light. When the right half of the gel is irradiated more strongly than the left, the waves move from right to left, i.e., from a high- to a low-frequency region of gel oscillations. Once the difference in intensity of irradiation reaches a certain threshold, it causes a wormlike motion of the gel from left to right, retrograde wave locomotion. If the difference is increased further, the gel comes to a stop. A further increase in the difference causes the gel to move again, but in the opposite direction, i.e., direct wave locomotion. The nonuniform illumination plays a role analogous to that of anchoring segments and appendages (such as limbs and wings) during cell migration and animal locomotion, which control the direction of locomotion by strengthening direct movement and/or inhibiting the opposite movement.

By using computational models, the researchers were able to describe these processes. Within the gel, there are regions where pulling forces predominate; pushing forces predominate in other areas. Variations in the intensity of the irradiation lead to different changes in the friction forces and the tensions in the gel. When these effects are added up, it is possible to predict in which direction a particular grid element of the gel will move.

One important finding from this model: special changes in the viscoelastic properties of the slime excreted by the snails and worms as they crawl are not required for locomotion, whether retrograde or direct.

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

Retrograde and Direct Wave Locomotion in a Photosensitive Self-Oscillating Gel by Lin Ren, Weibing She, Prof. Dr. Qingyu Gao, Dr. Changwei Pan, Dr. Chen Ji, and Prof. Dr. Irving R. Epstein. Angewandte Chemie International Edition DOI: 10.1002/anie.201608367 Version of Record online: 13 OCT 2016

© 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

This paper is behind a paywall.

For anyone curious about the song, there’s this from its Wikipedia entry (Note: Links have been removed),

“The Loco-Motion” is a 1962 pop song written by American songwriters Gerry Goffin and Carole King. “The Loco-Motion” was originally written for Dee Dee Sharp but Sharp turned the song down.[1] The song is notable for appearing in the American Top 5 three times – each time in a different decade, performed by artists from three different cultures: originally African American pop singer Little Eva in 1962 (U.S. No. 1);[2] then American band Grand Funk Railroad in 1974 (U.S. No. 1);[3] and finally Australian singer Kylie Minogue in 1988 (U.S. No. 3).[4]

The song is a popular and enduring example of the dance-song genre: much of the lyrics are devoted to a description of the dance itself, usually done as a type of line dance. However, the song came before the dance.

“The Loco-Motion” was also the second song to reach No. 1 by two different musical acts. The earlier song to do this was “Go Away Little Girl”, also written by Goffin and King. It is one of only nine songs to achieve this

I had not realized this song had such a storied past; there’s a lot more about it in the Wikipedia entry.

I hear the proteins singing

Points to anyone who recognized the paraphrasing of the title for the well-loved, Canadian movie, “I heard the mermaids singing.” In this case, it’s all about protein folding and data sonification (from an Oct. 20, 2016 news item on phys.org),

Transforming data about the structure of proteins into melodies gives scientists a completely new way of analyzing the molecules that could reveal new insights into how they work – by listening to them. A new study published in the journal Heliyon shows how musical sounds can help scientists analyze data using their ears instead of their eyes.

The researchers, from the University of Tampere in Finland, Eastern Washington University in the US and the Francis Crick Institute in the UK, believe their technique could help scientists identify anomalies in proteins more easily.

An Oct. 20, 2016 Elsevier Publishing press release on EurekAlert, which originated the news item, expands on the theme,

“We are confident that people will eventually listen to data and draw important information from the experiences,” commented Dr. Jonathan Middleton, a composer and music scholar who is based at Eastern Washington University and in residence at the University of Tampere. “The ears might detect more than the eyes, and if the ears are doing some of the work, then the eyes will be free to look at other things.”

Proteins are molecules found in living things that have many different functions. Scientists usually study them visually and using data; with modern microscopy it is possible to directly see the structure of some proteins.

Using a technique called sonification, the researchers can now transform data about proteins into musical sounds, or melodies. They wanted to use this approach to ask three related questions: what can protein data sound like? Are there analytical benefits? And can we hear particular elements or anomalies in the data?

They found that a large proportion of people can recognize links between the melodies and more traditional visuals like models, graphs and tables; it seems hearing these visuals is easier than they expected. The melodies are also pleasant to listen to, encouraging scientists to listen to them more than once and therefore repeatedly analyze the proteins.

The sonifications are created using a combination of Dr. Middleton’s composing skills and algorithms, so that others can use a similar process with their own proteins. The multidisciplinary approach – combining bioinformatics and music informatics – provides a completely new perspective on a complex problem in biology.

“Protein fold assignment is a notoriously tricky area of research in molecular biology,” said Dr. Robert Bywater from the Francis Crick Institute. “One not only needs to identify the fold type but to look for clues as to its many functions. It is not a simple matter to unravel these overlapping messages. Music is seen as an aid towards achieving this unraveling.”

The researchers say their molecular melodies can be used almost immediately in teaching protein science, and after some practice, scientists will be able to use them to discriminate between different protein structures and spot irregularities like mutations.

Proteins are the first stop, but our knowledge of other molecules could also benefit from sonification; one day we may be able to listen to our genomes, and perhaps use this to understand the role of junk DNA [emphasis mine].

About 97% of our DNA (deoxyribonucleic acid) has been known for some decades as ‘junk DNA’. In roughly 2012, that was notion was challenged as Stephen S. Hall wrote in an Oct. 1, 2012 article (Hidden Treasures in Junk DNA; What was once known as junk DNA turns out to hold hidden treasures, says computational biologist Ewan Birney) for Scientific American.

Getting back to  2016, here’s a link to and a citation for ‘protein singing’,

Melody discrimination and protein fold classification by  Robert P. Bywater, Jonathan N. Middleton. Heliyon 20 Oct 2016, Volume 2, Issue 10 DOI: 10.1016/j.heliyon.2016.e0017

This paper is open access.

Here’s what the proteins sound like,

Supplementary Audio 3 for file for Supplementary Figure 2 1r75 OHEL sonification full score. [downloaded from the previously cited Heliyon paper]

Joanna Klein has written an Oct. 21, 2016 article for the New York Times providing a slightly different take on this research (Note: Links have been removed),

“It’s used for the concert hall. It’s used for sports. It’s used for worship. Why can’t we use it for our data?” said Jonathan Middleton, the composer at Eastern Washington University and the University of Tampere in Finland who worked with Dr. Bywater.

Proteins have been around for billions of years, but humans still haven’t come up with a good way to visualize them. Right now scientists can shoot a laser at a crystallized protein (which can distort its shape), measure the patterns it spits out and simulate what that protein looks like. These depictions are difficult to sift through and hard to remember.

“There’s no simple equation like e=mc2,” said Dr. Bywater. “You have to do a lot of spade work to predict a protein structure.”

Dr. Bywater had been interested in assigning sounds to proteins since the 1990s. After hearing a song Dr. Middleton had composed called “Redwood Symphony,” which opens with sounds derived from the tree’s DNA, he asked for his help.

Using a process called sonification (which is the same thing used to assign different ringtones to texts, emails or calls on your cellphone) the team took three proteins and turned their folding shapes — a coil, a turn and a strand — into musical melodies. Each shape was represented by a bunch of numbers, and those numbers were converted into a musical code. A combination of musical sounds represented each shape, resulting in a song of simple patterns that changed with the folds of the protein. Later they played those songs to a group of 38 people together with visuals of the proteins, and asked them to identify similarities and differences between them. The two were surprised that people didn’t really need the visuals to detect changes in the proteins.

Plus, I have more about data sonification in a Feb. 7, 2014 posting regarding a duet based on data from Voyager 1 & 2 spacecraft.

Finally, I hope my next Steep project will include  sonification of data on gold nanoparticles. I will keep you posted on any developments.

Nano-decoy for human influenza A virus

While the implications for this research are exciting, keep in mind that so far they’ve been testing immune-compromised mice. An Oct. 24, 2016 news item on Nanowerk announces the research,

To infect its victims, influenza A heads for the lungs, where it latches onto sialic acid on the surface of cells. So researchers created the perfect decoy: A carefully constructed spherical nanoparticle coated in sialic acid lures the influenza A virus to its doom. When misted into the lungs, the nanoparticle traps influenza A, holding it until the virus self-destructs.

An Oct. 24, 2015 Rensselaer Polytechnic Institute press release by Mary L. Martialay, which originated the news item, describes the research (Note: Links have been removed),

In a study on immune-compromised mice, the treatment reduced influenza A mortality from 100 percent to 25 percent over 14 days. The novel approach, which is radically different from existing influenza A vaccines, and treatments based on neuraminidase inhibitors, could be extended to a host of viruses that use a similar approach to infecting humans, such as Zika, HIV, and malaria. …

“Instead of blocking the virus, we mimicked its target – it’s a completely novel approach,” said Robert Linhardt, a glycoprotein expert and Rensselaer Polytechnic Institute professor who led the research. “It is effective with influenza and we have reason to believe it will function with many other viruses. This could be a therapeutic in cases where vaccine is not an option, such as exposure to an unanticipated strain, or with immune-compromised patients.”

The project is a collaboration between researchers within the Center for Biotechnology and Interdisciplinary Studies (CBIS) at Rensselaer and several institutions in South Korea including Kyungpook National University. Lead author Seok-Joon Kwon, a CBIS research scientist, coordinated the project across borders, enabling the South Korean institutions to test a drug designed and characterized at Rensselaer. …

To access the interior of a cell and replicate itself, influenza A must first bind to the cell surface, and then cut itself free. It binds with the protein hemagglutinin, and severs that tie with the enzyme neuraminidase. Influenza A produces numerous variations each of hemagglutinin and neuraminidase, all of which are antigens within the pathogen that provoke an immune system response. Strains of influenza A are characterized according to the variation of hemagglutinin and neuraminidase they carry, thus the origin of the familiar H1N1 or H3N2 designations.

Medications to counter the virus do exist, but all are vulnerable to the continual antigenic evolution of the virus. A yearly vaccine is effective only if it matches the strain of virus that infects the body. And the virus has shown an ability to develop resistance to a class of therapeutics based on neuraminidase inhibitors, which bind to and block neuraminidase.

The new solution targets an aspect of infection that does not change: all hemagglutinin varieties of influenza A must bind to human sialic acid. To trap the virus, the team designed a dendrimer, a spherical nanoparticle with treelike branches emanating from its core. On the outermost branches, they attached molecules, or “ligands,” of sialic acid.

The research found that the size of the dendrimer and the spacing between the ligands is integral to the function of the nanoparticle. Hemagglutinin occurs in clusters of three, or “trimers,” on the surface of the virus, and researchers found that a spacing of 3 nanometers between ligands resulted in the strongest binding to the trimers. Once bound to the densely packed dendrimer, viral neuraminidase is unable to sever the link. The coat of the virus contains millions of trimers, but the research revealed that only a few links provokes the virus to discharge its genetic cargo and ultimately self-destruct.

A different approach, using a less structured nanoparticle, had been previously tested in unrelated research, but the nanoparticle selected proved both toxic, and could be inactivated by neuraminidase. The new approach is far more promising.

“The major accomplishment was in designing an architecture that is optimized to bind so tightly to the hemagglutinin, the neuraminidase can’t squeeze in and free the virus,” said Linhardt. “It’s trapped.”

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

Nanostructured glycan architecture is important in the inhibition of influenza A virus infection by Seok-Joon Kwon, Dong Hee Na, Jong Hwan Kwak, Marc Douaisi, Fuming Zhang, Eun Ji Park, Jong-Hwan Park, Hana Youn, Chang-Seon Song, Ravi S. Kane, Jonathan S. Dordick, Kyung Bok Lee, & Robert J. Linhardt. Nature Nanotechnology (2016)  doi:10.1038/nnano.2016.181 Published online 24 October 2016

This paper is behind a paywall.

US nanotechnology resource map

I have two links to the US National Nanotechnology Inititative’s (NNI) Nanotechnology Resource Map. Here’s the more confusing one: US Nanotechnology Resource Map: Higher Ed Programs and NNI Centers and User Facilities (from the homepage),

This interactive map shows the currently funded NNI Centers and User Facilities, as well as the nation’s higher education nanotechnology degrees– from community college through PhD programs.

Here’s the less confusing version: NNI’s Interactive
Nanotechnology Resource Map (from the About the map webpage),

With this interactive map tool, you can search for nanotechnology-related higher education and training programs, NNI Centers and User Facilities, as well as regional, state, and local initiatives in nanotechnology located throughout the country. In addition, the map provides the location of the facility, as well as a street view, directions to the site, and a link to the facility’s website.

This map is searchable by state, facility-type, or keyword. Hovering the mouse over a state creates a small pop up window that provides the statewide totals for the following figures:

  • Schools offering Bachelor Degree programs in nanotechnology
  • Schools offering Masters Degree programs in nanotechnology
  • Schools offering Ph.D. programs in nanotechnology
  • Community Colleges and Training Programs with nanotechnology courses and degree programs
  • National Nanotechnology Initiative Centers and User Facilities (laboratories)
  • Regional, state, & local initiatives in nanotechnology

….

  • You can narrow your search results by using the filter criteria and limit your search to your areas of interest, e.g., checking or unchecking the boxes or choosing a state from the drop down menu.
  • Alternatively, you can search by keyword or phrase and the results will be populated in tabular format under the map. Type “all” and all results will be displayed.
  • Clicking on a state will open a new window that displays the map of that state and the statewide results under the map as defined in the search criteria.
  • Clicking on a point on the map or a row in the table, will display more information about that particular institution.
  • From the main map, you can toggle the view at anytime between the state totals map and the cluster map that shows nationwide results.

Good luck!

Not enough silver nanoparticles in water supply to be harmful?

While the news of a low concentration of silver nanoparticles in the water supply seems good in the short term, one can’t help wondering what will happen as more of them end up in the our water. As for the news itself, here’s the announcement concerning a review of some 300 papers, from an Oct. 13, 2016 news item on Nanowerk,

Silver nanoparticles have a wide array of uses, one of which is to treat drinking water for harmful bacteria and viruses. But do silver nanoparticles also kill off potentially beneficial bacteria or cause other harmful effects to water-based ecosystems? A new paper from a team of University of Missouri College of Engineering researchers says that’s not the case.

An Oct. 12, 2016 University of Missouri news release (also on EurekAlert), which originated the news item, expands on the theme (Note: Links have been removed),

In their paper, “Governing factors affecting the impacts of silver nanoparticles on wastewater treatment,” recently published in Science of the Total Environment, Civil and Environmental Engineering Department doctoral students Chiqian Zhang and Shashikanth Gajaraj and Department Chair and Professor Zhiqiang Hu worked with Ping Li of the South China University of Technology to analyze the results of approximately 300 published works on the subject of silver nanoparticles and wastewater. What they found was while silver nanoparticles can have moderately or even significantly adverse effects in large concentrations, the amount of silver nanoparticles found in our wastewater at present isn’t harmful to humans or the ecosystem as a whole.

“If the concentration remains low, it’s not a serious problem,” Zhang said.

Silver nanoparticles are used in wastewater treatment and found increasingly in everyday products in order to combat bacteria. In terms of wastewater treatment, silver nanoparticles frequently react with sulfides in biosolids, vastly limiting their toxicity.

Zhang said many of the studies looked at high concentrations and added that if, over time, the concentration rose to much higher levels of several milligrams per liter or higher), toxicity could become a problem. But he explained that it would take decades or even longer potentially to get to that point.

“People evaluate the toxicity in a small-scale system,” he said. “But with water collection systems, much of the silver nanoparticles become silver sulfide and not be harmful.”

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

Governing factors affecting the impacts of silver nanoparticles on wastewater treatment by Chiqian Zhang, Zhiqiang Hu, Ping Li, Shashikanth Gajaraj. Science of The Total Environment http://dx.doi.org/10.1016/j.scitotenv.2016.07.145 Available online 16 August 2016

This study is behind a paywall.

For the curious, I have a Feb. 28, 2013 posting where I contrasted two silver nanoparticle studies one of which found little risk and the other which raised serious concerns. Scroll down about about 60% of the way for the ‘cautionary’ study.

Personally, I’m inclined to agree silver nanoparticles are not an immediate concern but since no one knows what the tipping point might be, now would be a good time to get serious about research, policies, and regulation.

Achieving ultra-low friction without oil

Oiled gears as small parts of large mechanism Courtesy: Georgia Institute of Technology

Oiled gears as small parts of large mechanism Courtesy: Georgia Institute of Technology

Those gears are gorgeous, especially in full size; I will be giving a link to a full size version in a bit. Meanwhile, an Oct. 11, 2016 news item on Nanowerk makes an announcement about ultra-low friction without oil,

Researchers at Georgia Institute of Technology [Georgia Tech; US] have developed a new process for treating metal surfaces that has the potential to improve efficiency in piston engines and a range of other equipment.

The method improves the ability of metal surfaces to bond with oil, significantly reducing friction without special oil additives.

“About 50 percent of the mechanical energy losses in an internal combustion engine result from piston assembly friction. So if we can reduce the friction, we can save energy and reduce fuel and oil consumption,” said Michael Varenberg, an assistant professor in Georgia Tech’s George W. Woodruff School of Mechanical Engineering.

An Oct. 5, 2016 Georgia Tech news release (also on EurekAlert but dated Oct. 11, 2016), which originated the news item, describes the research in more detail,

In the study, which was published Oct. 5 [2016] in the journal Tribology Letters, the researchers at Georgia Tech and Technion – Israel Institute of Technology tested treating the surface of cast iron blocks by blasting it with mixture of copper sulfide and aluminum oxide. The shot peening modified the surface chemically that changed how oil molecules bonded with the metal and led to a superior surface lubricity.

“We want oil molecules to be connected strongly to the surface. Traditionally this connection is created by putting additives in the oil,” Varenberg said. “In this specific case, we shot peen the surface with a blend of alumina and copper sulfide particles.  Making the surface more active chemically by deforming it allows for replacement reaction to form iron sulfide on top of the iron. And iron sulfides are known for very strong bonds with oil molecules.”

Oil is the primary tool used to reduce the friction that occurs when two surfaces slide in contact. The new surface treatment results in an ultra-low friction coefficient of about 0.01 in a base oil environment, which is about 10 times less than a friction coefficient obtained on a reference untreated surface, the researchers reported.

“The reported result surpasses the performance of the best current commercial oils and is similar to the performance of lubricants formulated with tungsten disulfide-based nanoparticles, but critically, our process does not use any expensive nanostructured media,” Varenberg said.

The method for reducing surface friction is flexible and similar results can be achieved using a variety of processes other than shot peening, such as lapping, honing, burnishing, laser shock peening, the researchers suggest. That would make the process even easier to adapt to a range of uses and industries. The researchers plan to continue to examine that fundamental functional principles and physicochemical mechanisms that caused the treatment to be so successful.

“This straightforward, scalable pathway to ultra-low friction opens new horizons for surface engineering, and it could significantly reduce energy losses on an industrial scale,” Varenberg said. “Moreover, our finding may result in a paradigm shift in the art of lubrication and initiate a whole new direction in surface science and engineering due to the generality of the idea and a broad range of potential applications.”

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

Mechano-Chemical Surface Modification with Cu2S: Inducing Superior Lubricity by Michael Varenberg, Grigory Ryk, Alexander Yakhnis, Yuri Kligerman, Neha Kondekar, & Matthew T. McDowell. Tribol Lett (2016) 64: 28. doi:10.1007/s11249-016-0758-8 First online: Oct. 5, 2016

This paper is behind a paywall.

Scaling up quantum dot, solar-powered windows

An Oct. 12, 2016 news item on phys.org announces that Los Alamos National Laboratory (US) may have taken a step towards scaling up quantum dot, solar-powered windows for industrial production (Note: A link has been removed),

In a paper this week for the journal Nature Energy, a Los Alamos National Laboratory research team demonstrates an important step in taking quantum dot, solar-powered windows from the laboratory to the construction site by proving that the technology can be scaled up from palm-sized demonstration models to windows large enough to put in and power a building.

“We are developing solar concentrators that will harvest sunlight from building windows and turn it into electricity, using quantum-dot based luminescent solar concentrators,” said lead scientist Victor Klimov. Klimov leads the Los Alamos Center for Advanced Solar Photophysics (CASP).

Los Alamos Center for Advanced Solar Photophysics researchers hold a large prototype solar window. From left to right: Jaehoon Lim, Kaifeng Wu, Victor Klimov, Hongbo Li.

Los Alamos Center for Advanced Solar Photophysics researchers hold a large prototype solar window. From left to right: Jaehoon Lim, Kaifeng Wu, Victor Klimov, Hongbo Li.

An Oct. 11, 2016 Los Alamos National Laboratory news release, which originated the news item, describes the work in more detail,

Luminescent solar concentrators (LSCs) are light-management devices that can serve as large-area sunlight collectors for photovoltaic cells. An LSC consists of a slab of transparent glass or plastic impregnated or coated with highly emissive fluorophores. After absorbing solar light shining onto a larger-area face of the slab, LSC fluorophores re-emit photons at a lower energy and these photons are guided by total internal reflection to the device edges where they are collected by photovoltaic cells.

At Los Alamos, researchers expand the options for energy production while minimizing the impact on the environment, supporting the Laboratory mission to strengthen energy security for the nation.

In the Nature Energy paper, the team reports on large LSC windows created using the “doctor-blade” technique for depositing thin layers of a dot/polymer composite on top of commercial large-area glass slabs. The “doctor-blade” technique comes from the world of printing and uses a blade to wipe excess liquid material such as ink from a surface, leaving a thin, highly uniform film behind. “The quantum dots used in LSC devices have been specially designed for the optimal performance as LSC fluorophores and to exhibit good compatibility with the polymer material that holds them on the surface of the window,” Klimov noted.

LSCs use colloidal quantum dots to collect light because they have properties such as widely tunable absorption and emission spectra, nearly 100 percent emission efficiencies, and high photostability (they don’t break down in sunlight).

If the cost of an LSC is much lower than that of a photovoltaic cell of comparable surface area and the LSC efficiency is sufficiently high, then it is possible to considerably reduce the cost of producing solar electricity, Klimov said. “Semitransparent LSCs can also enable new types of devices such as solar or photovoltaic windows that could turn presently passive building facades into power generation units.”

The quantum dots used in this study are semiconductor spheres with a core of one material and a shell of another. Their absorption and emission spectra can be tuned almost independently by varying the size and/or composition of the core and the shell. This allows the emission spectrum to be tuned by the parameters of the dot’s core to below the onset of strong optical absorption, which is itself tuned by the parameters of the dot’s shell. As a result, loss of light due to self-absorption is greatly reduced. “This tunability is the key property of these specially designed quantum dots that allows for record-size, high-performance LSC devices,” Klimov said.

The “LSC quantum dots” were synthesized by Jaehoon Lim (a postdoctoral research associate). Hongbo Li (postdoctoral research associate), and Kaifeng Wu (postdoctoral Director’s Fellow) developed the procedures for encapsulating quantum dots into polymer matrices and their deposition onto glass slabs by doctor-blading. Hyung-Jun Song (postdoctoral research associate) fabricated prototypes of complete LSC-solar-cell devices and characterized them.

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

Doctor-blade deposition of quantum dots onto standard window glass for low-loss large-area luminescent solar concentrators by Hongbo Li, Kaifeng Wu, Jaehoon Lim, Hyung-Jun Song, & Victor I. Klimov. Nature Energy 1, Article number: 16157 (2016) doi:10.1038/nenergy.2016.157 Published online: 10 October 2016

This paper is behind a paywall.

Nanorods as multistate switches

This research goes beyond the binary (0 or 1) and to an analog state that resembles quantum states. Fascinating, yes? An Oct. 10, 2016 news item on phys.org tells more,

Rice University scientists have discovered how to subtly change the interior structure of semi-hollow nanorods in a way that alters how they interact with light, and because the changes are reversible, the method could form the basis of a nanoscale switch with enormous potential.

“It’s not 0-1, it’s 1-2-3-4-5-6-7-8-9-10,” said Rice materials scientist Emilie Ringe, lead scientist on the project, which is detailed in the American Chemical Society journal Nano Letters. “You can differentiate between multiple plasmonic states in a single particle. That gives you a kind of analog version of quantum states, but on a larger, more accessible scale.”

Ringe and colleagues used an electron beam to move silver from one location to another inside gold-and-silver nanoparticles, something like a nanoscale Etch A Sketch. The result is a reconfigurable optical switch that may form the basis for a new type of multiple-state computer memory, sensor or catalyst.

An Oct. 10, 2016 Rice University news release, which originated the news item, describes the work in additional detail,

At about 200 nanometers long, 500 of the metal rods placed end-to-end would span the width of a human hair. However, they are large in comparison with modern integrated circuits. Their multistate capabilities make them more like reprogrammable bar codes than simple memory bits, she said.

“No one has been able to reversibly change the shape of a single particle with the level of control we have, so we’re really excited about this,” Ringe said.

Altering a nanoparticle’s internal structure also alters its external plasmonic response. Plasmons are the electrical ripples that propagate across the surface of metallic materials when excited by light, and their oscillations can be easily read with a spectrometer — or even the human eye — as they interact with visible light.

The Rice researchers found they could reconfigure nanoparticle cores with pinpoint precision. That means memories made of nanorods need not be merely on-off, Ringe said, because a particle can be programmed to emit many distinct plasmonic patterns.

The discovery came about when Ringe and her team, which manages Rice’s advanced electron microscopy lab, were asked by her colleague and co-author Denis Boudreau, a professor at Laval University in Quebec, to characterize hollow nanorods made primarily of gold but containing silver.

“Most nanoshells are leaky,” Ringe said. “They have pinholes. But we realized these nanorods were defect-free and contained pockets of water that were trapped inside when the particles were synthesized. We thought: We have something here.”

Ringe and the study’s lead author, Rice research scientist Sadegh Yazdi, quickly realized how they might manipulate the water. “Obviously, it’s difficult to do chemistry there, because you can’t put molecules into a sealed nanoshell. But we could put electrons in,” she said.

Focusing a subnanometer electron beam on the interior cavity split the water and inserted solvated electrons – free electrons that can exist in a solution. “The electrons reacted directly with silver ions in the water, drawing them to the beam to form silver,” Ringe said. The now-silver-poor liquid moved away from the beam, and its silver ions were replenished by a reaction of water-splitting byproducts with the solid silver in other parts of the rod.

“We actually were moving silver in the solution, reconfiguring it,” she said. “Because it’s a closed system, we weren’t losing anything and we weren’t gaining anything. We were just moving it around, and could do so as many times as we wished.”

The researchers were then able to map the plasmon-induced near-field properties without disturbing the internal structure — and that’s when they realized the implications of their discovery.

“We made different shapes inside the nanorods, and because we specialize in plasmonics, we mapped the plasmons and it turned out to have a very nice effect,” Ringe said. “We basically saw different electric-field distributions at different energies for different shapes.” Numerical results provided by collaborators Nicolas Large of the University of Texas at San Antonio and George Schatz of Northwestern University helped explain the origin of the modes and how the presence of a water-filled pocket created a multitude of plasmons, she said.

The next challenge is to test nanoshells of other shapes and sizes, and to see if there are other ways to activate their switching potentials. Ringe suspects electron beams may remain the best and perhaps only way to catalyze reactions inside particles, and she is hopeful.

“Using an electron beam is actually not as technologically irrelevant as you might think,” she said. “Electron beams are very easy to generate. And yes, things need to be in vacuum, but other than that, people have generated electron beams for nearly 100 years. I’m sure 40 years ago people were saying, ‘You’re going to put a laser in a disk reader? That’s crazy!’ But they managed to do it.

“I don’t think it’s unfeasible to miniaturize electron-beam technology. Humans are good at moving electrons and electricity around. We figured that out a long time ago,” Ringe said.

The research should trigger the imaginations of scientists working to create nanoscale machines and processes, she said.

“This is a reconfigurable unit that you can access with light,” she said. “Reading something with light is much faster than reading with electrons, so I think this is going to get attention from people who think about dynamic systems and people who think about how to go beyond current nanotechnology. This really opens up a new field.”

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

Reversible Shape and Plasmon Tuning in Hollow AgAu Nanorods by Sadegh Yazdi, Josée R. Daniel, Nicolas Large, George C. Schatz, Denis Boudreau, and Emilie Ringe. Nano Lett., Article ASAP DOI: 10.1021/acs.nanolett.6b02946 Publication Date (Web): October 5, 2016

Copyright © 2016 American Chemical Society

This paper is behind a paywall.

The researchers have made this video available for the public,

The Future of Federal Citizen Science and Crowdsourcing; a Nov. 15, 2016 event at the Wilson Center (Washington, DC)

I received this Oct. 25, 2016 notice from the Wilson Center in Washington, DC (US) via email,

Citizen Science and Crowdsourcing, a form of open innovation that engages the public in authentic scientific research, has many documented benefits like advancing research, STEM education and addressing societal needs. This method has gained significant momentum in the U.S. Federal government in the past four years. In September 2015 the White House issued a memorandum asking federal agencies to report on their citizen science and crowdsourcing projects and appoint coordinators within each agency. In 2016 we witnessed the launch of www.citizenscience.gov, a platform with an extensive toolkit on how to conduct these projects as well as a catalog and community hub. In addition to these Executive Branch initiatives, a grassroots Federal Community of Practice for Crowdsourcing and Citizen Science (CCS) has emerged with 300 members across 59 agencies. The Science and Technology Program (STIP) at the Wilson Center has played a role in encouraging this momentum, providing support through building a cartographic catalog of federally supported citizen science and crowdsourcing projects and through extensive research into some of the legal, administrative and intellectual property concerns for conducting projects within the Federal government.

However, a new Administration often brings new priorities, and it’s vital to preserve this momentum and history for new leadership. STIP conducted interviews with twelve representatives of the Federal Community of practice and Agency Coordinators and conducted desk research to compile 10 strategic recommendations for advancing federal policies and programs in citizen science and crowdsourcing to facilitate the transfer of knowledge on this incredible momentum.

Please join us for a discussion of these recommendations, a celebration of the history of the movement and a dialogue on the future of citizen science and crowdsourcing in the Federal government.

The speakers are:

Elizabeth Tyson

Co-Director, Commons Lab/Program Associate, Science and Technology Innovation Program

Anne Bowser

Co-Director, Commons Lab/ Senior Program Associate, Science and Technology Innovation Program

David Rejeski

Global Fellow

The logistics:

Tuesday, November 15th, 2016
1:30pm – 3:00pm

5th floor conference room

Wilson Center
Ronald Reagan Building and
International Trade Center
One Woodrow Wilson Plaza
1300 Pennsylvania, Ave., NW
Washington, D.C. 20004

Phone: 202.691.4000

You can register here and you can find the Wilson Center Federal Crowdsourcing and Citizen Science Catalog here.

In the past, there would be livestreaming of these events but I didn’t see a notice on the event webpage.