Entrepreneurons:  Practical Advice and Networking for Entrepreneurs

Fostering entrepreneurship at the UW-Madison: Executive Q&A|John Surdyk

 

Save the date (Sept 21-22, UW Eau Claire) - for the 2015 Regional Materials and Manufacturing Network (RM2N) Symposium!

Please join us for the kick off meeting that brings together materials science colleagues, students from campus member affiliates, and industry representatives.

Program includes :
a student poster session,
networking opportunities,
research and industrial talks.

Discussions will include how the RM2N network can better engage Wisconsin industry/manufacturers and the UW system schools and put us in a better position to take advantage of local expertise, instrumentation and other resources, and how this can work to benefit all

Susann Ely

parties.

More details to come! Please contact Susann Ely  ( sely@wisc.edu) if you have further questions or visit wiscmat.org

For more information, please contact Felix Lu or Erin Gill .

 Quartz Crystal Microbalance

The MRSEC is in the process of procuring a a QCM-D which will reside in the Soft Materials Laboratory in Engineering Hall.

A quartz crystal microbalance (QCM) measures a mass variation per unit area by measuring the change in

frequency of a quartz crystal resonator. The resonance is disturbed by the addition or removal of a small mass due to oxide growth/decay or film deposition at the surface of the acoustic resonator. The QCM can be used under vacuum, in gas phase ("gas sensor", first use described by King [1] ) and more recently in liquid environments. It is useful for monitoring the rate of deposition in thin film deposition systems under vacuum. In liquid, it is highly effective at determining the affinity of molecules ( proteins , in particular) to surfaces functionalized with recognition sites. Larger entities such as viruses or polymers are investigated, as well. QCM has also been used to investigate interactions between biomolecules. Frequency measurements are easily made to high precision (discussed below); hence, it is easy to measure mass densities down to a level of below 1 ?g/cm2. In addition to measuring the frequency, the dissipation factor (equivalent to the resonance bandwidth) is often measured to help analysis. The dissipation factor is the inverse quality factor of the resonance, Q?1 = w/fr (see below); it quantifies the damping in the system and is related to the sample's viscoelastic 

properties.

[Source: Wikipedia]

If you have any questions about these instruments, please contact Felix Lu ( fplu@wisc.edu) or call me at (608) 262-6099.

 

  ( http://www.fisher-barton.com/ )

Do you want to submit a member  spotlight for your company? Please contact Felix Lu ( fplu@wisc.edu) for more details.

 

link to : mPrep Workshop Information

Do you want to submit a member  spotlight for your company? Please contact Felix Lu ( fplu@wisc.edu) for more details.

 

[Read more: http://www.news.wisc.edu/23592

[Read more: http://www.news.wisc.edu/23585

 

 

A LOT of tosh is talked about "nanotechnology", much of it designed to separate unwary investors from their hard-earned cash. This does not mean, though, that controlling the structure of things at the level of nanometres (billionths of a metre) is unimportant. In materials science it is vital, as a paper just published in Nature, by Hansoo Kim and his colleagues at the Pohang University of Science and Technology, in South Korea, demonstrates. By manipulating the structure of steel on a nanometre scale, Dr Kim has produced a material which has the strength and the lightness of titanium alloys but will, when produced at scale, cost a tenth as much.

Steel is useful because it is strong and cheap. But it is also heavy. It has, therefore, always been useless for applications such as aircraft. In a world that demands the ever-more efficient use of fuel in motor cars and lorries, it is now falling out of favour there, too. According to Dr Kim, the share by weight of steel in an average light vehicle fell from 68.1% in 1995 to 60.1% in 2011.

 

Read more at: http://www.economist.com/news/science-and-technology/21642107-alloy-iron-and-aluminium-good-titanium-tenth

 

Samples show some of the colors researchers have produced in electrochromic polymers. The materials can be used for applications such as sunglasses and window tinting that can be turned on and off through the application of an electrical potential. Image: Rob Felt

Artists, print designers and interior decorators have long had access to a broad palette of paint and ink colors for their work. Now, researchers have created a broad color palette of electrochromic polymers, materials that can be used for sunglasses, window tinting and other applications that rely on electrical current to produce color changes.

By developing electrochromic polymer materials in a range of primary and secondary colors and combining them in specific blends, the researchers have covered the color spectrum - even creating four shades of brown, a particularly difficult color combination. The materials could be used to make sunglasses that change from tinted to clear in a matter of seconds, at the press of a button. Other uses could include window tinting, signage and even greeting cards that change color through the application of low-voltage electrical current.

Supported by BASF, the research is reported in ACS Applied Materials & Interfaces. The research was done in the laboratory of John Reynolds, a professor in the School of Chemistry and Biochemisty and the School of Materials Science and Engineering at the Georgia Institute of Technology.

"We've demonstrated the ability to create virtually any color we want by mixing different electrochromic polymers, just like mixing paint," said Anna ?sterholm, a research scientist in Georgia Tech's School of Chemistry and Biochemistry and the paper's first author. "Using a simple coating method or even inkjet printing, we can create films that change color with the application of a voltage."

 

Read more at: http://www.rdmag.com/news/2015/02/electrochromic-polymers-create-broad-color-palette-sunglasses-windows?et_cid=4406566&et_rid=614174443&type=headline

 

Journal article: http://pubs.acs.org/doi/abs/10.1021/am507063d

Forces exerted by the cells surrounding the gap (dotted blue line) extend away at first, then direct inwards, towards the gap, during contraction of the 'purse-string' cable (red filaments). Image: Mechanobiology Institute, National Univ. of Singapore

A collaborative study led by scientists from the Mechanobiology Institute (MBI) at the National Univ. of Singapore (NUS) has revealed the mechanical forces that drive epithelial wound healing in the absence of cell supporting environment. This research was published in Nature Communications.

Sealing the gaps
Skin not only provides an essential protective barrier against foreign materials and pathogens, but it also helps the body retain various fluids and electrolytes. When this barrier is damaged, the consequences can be devastating. Ulcers, bleeding and bacterial infections may result and the chances of these occurring increases the longer wounds remain open.

Fortunately, epithelial cell sheets are self-repairing. The moment the integrity of the barrier is compromised, cellular mechanisms are initiated to close the gap. Cells begin crawling forward, and contractile cables are formed in the cells surrounding the wound to help pull the gap close. For several years, scientists have been learning much about how cells coordinate these processes and repair wounds quickly. In most cases, the healthy skin cells responsible for carrying out wound repair rely on a supporting layer underneath them. This layer comprises sticky proteins, and is known as the extracellular matrix (ECM), which provides support for them to adhere to and crawl over.

However, in cases of chronic or severe wounds, the underlying layers could also be damaged. Surrounding cells could also be unable to replace the ECM proteins. Yet the repair of these gaps, known as non-adherent gaps, does occur, albeit at a slower rate and with an increased likelihood of infection or other complications. So the question remained; how do cells close gaps in protective epithelial barriers where the underlying layers are also damaged or the ECM eroded?

 

 

 

Read more at: http://www.rdmag.com/news/2015/02/forcing-wounds-close?et_cid=4406566&et_rid=614174443&type=headline

 

Journal article: Vedula et al., Mechanics of epithelial closure over non-adherent environments, Nature Communications, 22 Jan 2015, doi: 10.1038/ncomms7111

Advanced manufacturing industries usually boast an advanced supplier base. A case in point is the newly operational vertical bloom caster at TimkenSteel's Faircrest Plant, which supplies premium steel alloys to forging plants.

Forging is not only an enduring industry, but it is also an advanced industry. Despite Western society's disdain for old and improperly labeled "archaic" metalworking industries (such as foundry or forging), the U.S. forging industry is anything but archaic. In fact, the industry is vibrant, technologically challenging and critical to the country's economic health and defense. Not unlike the ancient workers of bronze or iron, today's workers of steel, aluminum, superalloys and titanium are critical to the current prosperity and future defense of the U.S.

Recognizing that there are many so-called "advanced manufacturing" technologies - e.g., nanotechnology, additive manufacturing, energy systems (batteries, wind power, compressed gas systems, etc.) - we have collaborated to write this article (and those to follow) to illustrate the significance of this critical, enabling metal-forging industry. This is the first in a series of articles we prepared to illustrate the value and necessity of forgings that enable the design and manufacture of high-performance systems in transportation, energy, biomedical and defense, to name but a few. Without the forging industry - an advanced manufacturing industry - the U.S. would be at a tremendous disadvantage in the international marketplace.

 

Defining Advanced Manufacturing

Along with the current renaissance of manufacturing in America, the label advanced manufacturing has been applied to "new" manufacturing technologies. Considerable discussion amongst the "manufacturing intelligentsia" has offered numerous definitions of advanced manufacturing depending on the viewpoint of the industry.

 

 

Read more at: http://www.forgemag.com/articles/84311-north-american-forging-is-advanced-manufacturing 

Leidenfrost effect power

Martian colonists could use an innovative new technique to harvest energy from carbon dioxide thanks to research pioneered at Northumbria and Edinburgh Universities. 

The technique, which has been proven for the first time by researchers at the two Universities, has been published in the prestigious journal Nature Communications.

The technique has exciting implications for working in extreme and alien environments, such as outer space, where it could be used to make long-term exploration and colonisation sustainable by using naturally occurring solid carbon dioxide as a resource rather than a waste product. If this could be realised, then future missions to Mars, such as those in the news recently, may not need to be 'one-way' after all.

Dry ice may not be abundant on Earth, but increasing evidence from NASA's Mars Reconnaissance Orbiter (MRO) suggests it may be a naturally occurring resource on Mars as suggested by the seasonal appearance of gullies on the surface of the red planet. If utilised in a Leidenfrost-based engine dry-ice deposits could provide the means to create future power stations on the surface of Mars. journal Nature Communications.

The research proposes a new kind of engine for producing energy based on the Leidenfrost effect - a phenomenon which happens when a liquid comes into near contact with a surface much hotter than its boiling point. This effect is commonly seen in the way water appears to skitter across the surface of a hot pan, but it also applies to solid carbon dioxide, commonly known as dry ice. Blocks of dry ice are able to levitate above hot surfaces protected by a barrier of evaporated gas vapour. Northumbria's research proposes using the vapour created by this effect to power an engine. This is the first time the Leidenfrost effect has been adapted as a way of harvesting energy.

 

 

 

Read more at: https://www.northumbria.ac.uk/about-us/news-events/news/2015/03/breakthrough-in-energy-harvesting-could-power-life-on-mars/  

 

Journal link: http://www.nature.com/ncomms/2015/150303/ncomms7390/full/ncomms7390.html  

Reactive molecular dynamics of Electrochemical Metallization Cell

Researchers have used an advanced model to simulate in unprecedented detail the workings of "resistance-switching cells" that might replace conventional memory for electronics applications, with the potential to bring faster and higher capacity computer memory while consuming less energy.

These electromechanical "metallization cells" rapidly switch from high resistance to low resistance-a two-state operation that could be used to represent the ones and zeros in the binary code needed to carry out software commands and store information in computers.

Researchers at Purdue Univ. developed a new method to simulate the electrochemical processes that govern the operation with atomistic detail. The researchers used the model to simulate the performance of a type of resistance-switching cells also called conductive bridging cells.

"Despite their importance, the mechanisms that govern their remarkable properties have been poorly understood, limiting our ability to assess the ultimate performance and potential for commercialization," said Alejandro Strachan, a professor of materials engineering at Purdue. "Now, an atomic-level mechanistic understanding of the switching process provides new guidelines for materials optimization."

The resistance-switching cells are being considered as a possible replacement for current non-volatile memory, which is reaching its technological limits and could also be used for logic applications. The conductive bridging cells can switch in a matter of nanoseconds-making them potentially capable of ultra-fast operation-and they are extremely small, possibly allowing for more compact, powerful computer memory, Strachan said.

Findings are detailed in Nature Materials. The paper was authored by Purdue postdoctoral research associate Nicolas Onofrio, graduate student David Guzman and Strachan.

The devices contain two metallic electrodes separated by a dielectric, or insulating material. As a voltage is applied, the active electrode-made of copper in this case-dissolves in the dielectric and the ions start moving toward the inactive electrode. These ions eventually form a conductive filament that connects the two electrodes, reducing the electrical resistance. When the voltage is reversed, the filaments break, switching back to the high-resistance state.

The researchers were able to simulate for the first time what happens at the actual nanoscale size and time regimes of the devices, yielding new information about how the filaments form and break. Findings provide new insights into the electrochemical reactions leading to the formation of the filaments and their breakup, predicting the ultra-fast operation observed in previous experiments with larger devices, with switching as fast as a few nanoseconds.

The emergence of such advanced simulations is making it possible to predict the precise behavior and performance of new devices before they've been constructed, a goal of the Materials Genome Initiative formed in 2011.

 

 

 

Read more at: http://www.rdmag.com/news/2015/03/simulations-provide-new-insight-emerging-nanoelectronic-device?et_cid=4449310&et_rid=614174443&type=cta

 

Journal link: Atomic origin of ultrafast resistance-switching in nanoscale eletrometallization cells    

Dan Buttry, professor and chair of ASU's Dept. of Chemistry and Biochemistry, examines a battery sample with graduate student Tylan Watkins. Image: Mary Zhu

Lithium-ion batteries are common in consumer electronics. They are one of the most popular types of rechargeable batteries for portable electronics, with a high energy density, no memory effect and only a slow loss of charge when not in use. Beyond consumer electronics, lithium-ion batteries have also grown in popularity for military, electric vehicle and aerospace applications.

Now, researchers at Arizona State Univ. are exploring new energy storage technology that could give the battery an even longer lifecycle.

Led by Dan Buttry, professor and chair of ASU's Dept. of Chemistry and Biochemistry, the research also involves former undergraduate researcher Jarred Olsen and current graduate student Tylan Watkins. Olsen joined Buttry's group as an undergraduate researcher to work in the ionic liquids area. The work he contributed to this study was performed while he was on an internship at Boulder Ionics working at both Boulder and ASU with Watkins. Olsen is currently a doctoral student at the Univ. of Washington, Seattle.

The research, published in Nature Communications, brings together scientists from Arizona State Univ., Univ. of Colorado at Boulder, Sandia National Laboratories, Boulder Ionics Corporation and Seoul National Univ., Korea.

Prolonging the lifecycle
Room temperature ionic liquids have attracted a great deal of interest in recent years due to their remarkable physicochemical properties, including high thermal stability, wide electrochemical window and low vapor pressure.

"We used a device called a quartz crystal microbalance to measure very tiny mass changes in thin films at the surface of the battery material during charging and discharging," said Buttry. "One of the key features of successful lithium battery materials is that they develop thin films that protect the surface of the battery electrodes, which prolongs the life of the battery. This study documents the development of just such a film in a new type of battery formulation that has many more attractive features than existing commercial lithium batteries."

Buttry added: "The hope is that this new formulation will find its way into commercial use."

The work is part of a larger effort in Buttry's lab that has included funding from the Advanced Research Projects Agency - Energy (ARPA-E) and now from the Army Research Office.

"These were not trivial measurements to make because composite films (meaning a film of the active material in a polymer matrix) are often difficult to use with a quartz crystal microbalance," said Watkins. "Most, if not all, quartz crystal microbalance studies of this sort use very thin films of the active material alone, which means specialty deposition methods must be used. What was cool here is that we were able to make the measurement on a more practical film, something you might realistically see in a commercial battery."

 

 

 Slides from ThermoScientific: From surface to cell - understanding the Li-ion battery 

 

 

Read more at: http://www.rdmag.com/news/2015/03/researchers-explore-longer-lifecycle-batteries?et_cid=4449310&et_rid=614174443&type=cta  

 

Journal link: http://www.nature.com/ncomms/2015/150225/ncomms7230/abs/ncomms7230.html

This is an artist's rendition of the high pressure thermal conductance experiment in a diamond anvil cell. The flat tips of the diamond anvils are less than half a millimeter in diameter, and the metal film (gray), ruby sphere (red), and pressure medium (blue fluid) are sealed between the diamonds by a metal gasket (solid purple). Image: Alex D. Jerez Roman, Visualization Laboratory, Beckman Institute, Univ. of Illinois

With more than five times the thermal conductivity of copper, diamond is the ultimate heat spreader. But the slow rate of heat flow into diamond from other materials limits its use in practice. In particular, the physical process controlling heat flow between metals and diamond has remained a mystery to scientists for many years.

By applying extreme pressure in a diamond anvil cell to metal films on diamond, researchers at the Univ. of Illinois at Urbana-Champaign have now determined the physical process dominating this unexplained heat flow, which has implications for understanding and improving heat flow between any two materials.

"Overheating has become a major limiting factor in the performance of high-power RF devices," said David Cahill, a professor and head of the Dept. of Materials Science and Engineering at Illinois. "Modern RF electronics for wireless devices such as satellites and cellphones generate so much heat in a microscopic area that the packing density and performance of RF devices isn't limited by Moore's Law anymore, so much as by how fast we can pull heat away from those devices. For overheating at microscopic length scales, it's not enough to just swap out silicon for diamond; we need a microscopic understanding of how heat enters materials like diamond."

Cahill explained that this work lies more on the fundamental side of thermal physics research, although materials like diamond and silicon carbide are being actively developed as alternative substrates for high powered radio-frequency (RF) devices. "Studies of extremes like metals on diamond at high pressure are valuable because they allow us to test our ideas about what is happening in this complex problem. The experiments we designed let us test and falsify a series of hypotheses, ultimately leading to a better understanding of heat flow between dissimilar materials."

"The simplest way for a phonon to cross an interface is by a two-phonon elastic processes: a phonon comes in, a phonon of the same frequency goes out." explained Greg Hohensee, first author of the paper appearing in Nature Communications. "But metals on diamond are a special case. The diamond is so stiff that it's like banging a pot attached to a rope and expecting the rope to dance. The vibrations stay in the pot, because the rope is not stiff enough to carry such high frequency vibrations. Likewise, you can't make the pot sing by shaking the rope. But somehow, metals on diamond are doing exactly that."

The thermal conductance of an interface determines the rate of heat flow for a given temperature difference between the materials. Typically, the carriers for heat in crystalline materials like diamond are traveling vibrational waves called phonons. A central challenge of thermal physics-and of interfacial thermal conductance, specifically-is that phonons exist over a wide frequency range, and how phonons interact with interfaces and other phonons depends on their frequencies.

 

Read more at:  http://www.rdmag.com/news/2015/03/squeezing-out-new-science-materials-interfaces?et_cid=4450165&et_rid=614174443&type=cta 

 

Journal link: http://www.nature.com/ncomms/2015/150306/ncomms7578/full/ncomms7578.html

A small honeycomb structure cloaked the cylinder beneath from being felt

Physicists are abuzz with possibilities for "metamaterials" that can be designed to have surprising properties.

Tweaking the structure of materials to manipulate things like their appearance is already fairly well-known; the next phase is changing their mechanics.

A major conference is alive with ideas, designs and samples including springy ceramics, unfeelability cloaks and programmable rubber sponges. They could help build spacecraft tiles or even terrain-sensitive shoe soles. "I think this idea of metamaterials is slowly migrating into different areas," said Prof Martin Wegener, from the Karlsruhe Institute of Technology in Germany.

"Originally the excitement was all about electromagnetism - and then it went to totally different areas like thermodynamics and, lately, mechanics."

 

Prof Wegner also told the BBC that the term "metamaterial" has been applied to all sorts of weird and wonderful designs, without much consistency - but that it usually refers to a case where unusual properties jump out, which would not be expected from the original ingredients.

 

Now you feel it

Prof Wegener works on cloaking, but his aim is not to make things invisible. He wants to hide them from physical forces, and last year his lab produced a honeycomb-like material that made an object beneath it unfeelable.

This particular metamaterial was a solid lattice that acts like a fluid in certain ways, deflecting pressure around its hidden cargo.

Now the tiny, hidden cylinder was very small in that case (less than 1mm) but related work by Prof Wegener's team was picked up by French physicists and engineers, who showed that a careful pattern of drilled holes could divert damaging earthquake vibrations.

Turning the ground itself into a sort of metamaterial, it seems, might go so far as to protect a power station from a tremor.

Here at the American Physical Society's March Meeting, Prof Wegener presented his latest work - which includes cloaking a hole at the centre of a flat sheet - saying: "It's a design principle. You can apply it to anything you want."

 

 

Read more at:  http://www.bbc.com/news/science-environment-31725045 

 

A 3-D rendering of fibrin forming a blood clot, with PolySTAT (in blue) binding strands together. Image: William Walker/Univ. of Washington

Most military battlefield casualties die before ever reaching a surgical hospital. Of those soldiers who might potentially survive, most die from uncontrolled bleeding.

In some cases, there's not much medics can do-a tourniquet won't stop bleeding from a chest wound, and clotting treatments that require refrigerated or frozen blood products aren't always available in the field.

That's why Univ. of Washington researchers have developed a new injectable polymer that strengthens blood clots, called PolySTAT. Administered in a simple shot, the polymer finds any unseen or internal injuries and starts working immediately.

The new polymer, described in a paper featured in Science Translational Medicine, could become a first line of defense in everything from battlefield injuries to rural car accidents to search and rescue missions deep in the mountains. It has been tested in rats, and researchers say it could reach human trials in five years.

In the initial study with rats, 100% of animals injected with PolySTAT survived a typically-lethal injury to the femoral artery. Only 20% of rats treated with a natural protein that helps blood clot survived.

"Most of the patients who die from bleeding die quickly," said co-author Dr. Nathan White, an assistant professor of emergency medicine who teamed with UW bioengineers and chemical engineers to develop the macromolecule.

"This is something you could potentially put in a syringe inside a backpack and give right away to reduce blood loss and keep people alive long enough to make it to medical care," he said.

The UW team was inspired by factor XIII, a natural protein found in the body that helps strengthen blood clots.

Normally after an injury, platelets in the blood begin to congregate at the wound and form an initial barrier. Then a network of specialized fibers-called fibrin-start weaving themselves throughout the clot to reinforce it.

If that scaffolding can't withstand the pressure of blood pushing against it, the clot breaks apart and the patient keeps bleeding.

Both PolySTAT and factor XIII strengthen clots by binding fibrin strands together and adding "cross-links" that reinforce the latticework of that natural bandage.

"It's like the difference between twisting two ropes together and weaving a net," said co-author Suzie Pun, the UW's Robert J. Rushmer Professor of Bioengineering. "The cross-linked net is much stronger."

But the synthetic PolySTAT offers greater protection against natural enzymes that dissolve blood clots. Those help during the healing process, but they work against doctors trying to keep patients from bleeding to death.

 

 

 

Read more at:  

http://www.rdmag.com/news/2015/03/injectable-polymer-could-prevent-bleeding-death?et_cid=4457139&et_rid=614174443&type=cta

 

 

Rendering of the molecular structure of sodium disilicate glass. Researchers have identified a way to produce glass that is more durable. Image: UCLA Engineering

Researchers at the Univ. of California, Los Angeles (UCLA) Henry Samueli School of Engineering and Applied Science and the Univ. Pierre et Marie Curie in Paris have identified a method for manufacturing longer-lasting and stronger forms of glass. The research could lead to more durable display screens, fiber-optic cables, windows and other materials, including cement. 

Glasses are liquids that are cooled in the manufacturing process to reach a stable "frozen liquid" state. However, as glass ages and is exposed to temperature variations, it continues to flow or "relax," causing it to change shape.

This means that over time, windows and digital screens can deform, eventually becoming unusable. In the case of cement, which has a molecular structure similar to that of glass, relaxation eventually leads to cracking and, in bridges and tall buildings, a loss of structural integrity.

Mathieu Bauchy, an assistant professor of civil and environmental engineering at UCLA, and Matthieu Micoulaut, a professor of materials science at the Univ. Pierre et Marie Curie, have identified optimal conditions for developing more durable glass and cement.  

By performing computer simulations to test the molecular dynamics of materials commonly used to make glass, the researchers identified a range of pressures that are best for achieving "thermal reversibility," in which a material will retain the same properties it had when it was produced, even if it has been exposed over time to variations in temperature.

The research was published in Nature Communications.

"The key finding is that if you use specific conditions to form glass-the right pressure and the right composition of the material-you can design reversible glasses that show little or no aging over time," Bauchy said.

Bauchy said the molecular structure of glass is analogous to the metal framework of the Eiffel Tower. Strength and rigidity are partially a result of the angles at which beams and crossbeams connect. The researchers' new process improves the angles at which molecular bonds occur, making the material stronger.

 

Read more at:  http://www.rdmag.com/news/2015/03/process-identified-improving-durability-glass?et_cid=4457139&et_rid=614174443&type=cta  

 

Color change in an adult male panther chameleon resulting from excitation caused by the presentation of another adult male in its field of vision. (Credit: EpiPhysX science channel/Youtube/Nature Communications)

Everyone knows that chameleons are the kings of camouflage. But as to the exact process by which these familiar lizards change color to match their environment, no one knew.

Until now.

Previous research suggested that the color change resulted from shifting skin pigments. That's something known to occur in many species of fish, amphibians, and reptiles.

But new research conducted at the University of Geneva in Switzerland suggests that this isn't quite right. When researchers there studied the panther chameleon (Furcifer pardalis), they discovered that the color change is the result of light reflecting off microscopic crystals moving around in the animals' skin. As the crystals change their orientation, so do the wavelengths of light they reflect.

"We discovered that the animal changes its colors via the active tuning of a lattice of nanocrystals," the study's co-authors, physicist Dr. J?r?mie Teyssier and biologist Dr. Suzanne Saenko, said in a written statement. "When the chameleon is calm, the latter are organized into a dense network and reflect the blue wavelengths. In contrast, when excited, it loosens its lattice of nanocrystals, which allows the reflection of other colors, such as yellows or reds."

Next, the researchers hope to study the mechanism that underlies the movement of the nanocrystals. They say this line of research could help engineers develop color-changing materials that could be used for camouflage, Newsweek reported.

The study was published online Mar. 10 in the journal Nature Communications. 

 

 

Read more at:  http://www.huffingtonpost.com/2015/03/11/chameleons-change-color-crystals_n_6847984.html?ncid=newsltushpmg00000003 

 

Photo: Lars Sahl

Giant leaps have been made in recent years with 3-D printing. Though most 3-D printed items are made of plastic, more exotic ingredients have included sugar, mashed potatoes, and living cells. A 3-D printer commonly works by depositing a layer of material much like an ordinary printer and then printing out another layer once the material below has solidified. This procedure has a built-in problem: Even small objects take way too long to produce.

An object just several centimeters high can take hours to print. But now scientists at Carbon3D in Redwood City, Calif., and the University of North Carolina at Chapel Hill (UNC) say they can slash printing times by two orders of magnitude. Instead of printing an item step by step and layer by layer, the new technique prints objects in a continuous manner.

A 3-D printer often uses ultraviolet light to harden resins, but oxygen in the air often slows this hardening down. Instead of treating oxygen as an obstacle they had to overcome, the researchers used it to their advantage.

The new 3-D printer starts with a basin filled with a pool of liquid resin. Ultraviolet rays can emerge from beneath through a hole at the bottom of this basin. (Imagine a sink filled with resin where ultraviolet light can shine up from the drain.)

In the hole between the basin and ultraviolet rays, where a stopper might fill the hole at the bottom of a sink, is a layer of oxygen-rich liquid tens of micrometers thick. This layer serves as a transparent window for the ultraviolet rays. Solidification cannot occur in this "dead zone."

 

 

 

Read more at:  http://spectrum.ieee.org/tech-talk/at-work/innovation/liquid-3d-printing 

 

Photo: Martin Barraud/Getty Images

Foreign-born talent has fueled many Silicon Valley startups and contributed heavily to U.S. leadership in in science and engineering for decades. But national data shows that just half of science and engineering doctoral recipients who were born overseas end up staying in the U.S. to pursue their post-graduation careers. A new study has teased out several reasons why students choose to stay in the U.S. or go back to their home countries.

The limitations of U.S. immigration policy and H-1B work visas are one of the biggest challenges for foreign students interested in pursuing U.S. careers. That's according to a survey of 166 international graduate students conducted by the Center for Nanotechnology in Society at the University of California, Santa Barbara. Many students who participated in the survey pointed to uncertainty about obtaining permanent resident status after graduation as a major deterrent to both studying in the U.S. and trying to work in the U.S. after graduation. For the study, which appeared in the 11 March 2015 issue of the journal PLOS One, one mechanical engineering student summed up the frustrations of many peers thusly:

The fact that you don't have a green card at the end of your PhD-it's a nightmare. For international students, not having a green card, it impacts the job search, everything. The U.S. is welcoming to graduate students to come and study but there doesn't seem to be a plan for after students graduate. Students settle for jobs that are below them because they work for companies that will provide them with a green card.

But the study also examined how several professional, social and personal factors influenced the decisions of foreign students. The study authors focused on three key decisions: whether to pursue higher education in the home country, whether to stay in the U.S. or return home after graduation, and whether to pursue a career in academia or industry.

One of the strongest predictors of whether a student will stay or leave is whether he or she wants to pursue a career in academia or industry. Students who wanted industry careers had a 90 percent probability of pursuing U.S.-based careers after graduation. By comparison, students who planned to pursue academic careers believed they would receive better treatment from colleagues in their home country. As a result, this group had an 86 percent probability of leaving the U.S. after graduation.

 

Read more at:  http://spectrum.ieee.org/tech-talk/at-work/tech-careers/why-international-engineering-and-science-students-stay-or-go  

 

Image: U.S. Naval Research Laboratory

Lately there has been a trend in graphene research to imbue the material with both magnetic and electric properties. But just two years ago, the research world was pretty impressed that a team in Spain was able to make graphene magnetic alone.

Now researchers at the U.S. Naval Research Laboratory (NRL) have gone back to imparting just magnetic properties into graphene, and in so doing may have developed a method that could lead to graphene becoming a new data storage medium capable of a million-fold increase in capacity over today's hard drives.

While previous methods for magnetizing graphene involved putting defects into it or adding chemical groups to it, this new method the NRL researchers developed, which is described in the journal Advanced Materials, is actually a simple and seemingly scalable process. The result is that it can produce large-area magnetic graphene that can be easily patterned.

The production technique starts with putting a layer of graphene over a silicon wafer. The graphene-covered silicon wafer is then placed into cryogenic ammonia that contains a small amount of lithium. This process adds hydrogen to the wafer, which makes it ferromagnetic.

While that is a pretty neat feat, what surprised the researchers was just how evenly the magnetism was spread across the wafer.

 

 

Read more at:  http://spectrum.ieee.org/nanoclast/semiconductors/materials/graphene-promises-a-millionfold-increase-in-data-storage-capacity  

 

This figure shows the change in near surface temperatures over time with ocean pipes and without pipes. Image: Lester Kwiatkowski, Ken Caldeira and Katharine Ricke

To combat global climate change caused by greenhouse gases, alternative energy sources and other types of environmental recourse actions are needed. There are a variety of proposals that involve using vertical ocean pipes to move seawater to the surface from the depths in order to reap different potential climate benefits. A new study from a group of Carnegie scientists determines that these types of pipes could actually increase global warming quite drastically. It is published in Environmental Research Letters.

One proposed strategy-called Ocean Thermal Energy Conversion, or OTEC-involves using the temperature difference between deeper and shallower water to power a heat engine and produce clean electricity. A second proposal is to move carbon from the upper ocean down into the deep, where it wouldn't interact with the atmosphere. Another idea, and the focus of this particular study, proposes that ocean pipes could facilitate direct physical cooling of the surface ocean by replacing warm surface ocean waters with colder, deeper waters.

"Our prediction going into the study was that vertical ocean pipes would effectively cool the Earth and remain effective for many centuries," said Ken Caldeira, one of the three co-authors.

The team, which also included lead author Lester Kwiatkowski as well as Katharine Ricke, configured a model to test this idea and what they found surprised them. The model mimicked the ocean-water movement of ocean pipes if they were applied globally reaching to a depth of about a kilometer (just over half a mile). The model simulated the motion created by an idealized version of ocean pipes, not specific pipes. As such the model does not include real spacing of pipes, nor does it calculate how much energy they would require.

Their simulations showed that while global temperatures could be cooled by ocean pipe systems in the short term, warming would actually start to increase just 50 years after the pipes go into use. Their model showed that vertical movement of ocean water resulted in a decrease of clouds over the ocean and a loss of sea-ice.

Colder air is denser than warm air. Because of this, the air over the ocean surface that has been cooled by water from the depths has a higher atmospheric pressure than the air over land. The cool air over the ocean sinks downward reducing cloud formation over the ocean. Since more of the planet is covered with water than land, this would result in less cloud cover overall, which means that more of the Sun's rays are absorbed by Earth, rather than being reflected back into space by clouds.

Water mixing caused by ocean pipes would also bring sea ice into contact with warmer waters, resulting in melting. What's more, this would further decrease the reflection of the Sun's radiation, which bounces off ice as well as clouds.

After 60 years, the pipes would cause an increase in global temperature of up to 1.2 C (2.2 F). Over several centuries, the pipes put the Earth on a warming trend towards a temperature increase of 8.5 C (15.3 F).

"I cannot envisage any scenario in which a large scale global implementation of ocean pipes would be advisable," Kwiatkowski said. "In fact, our study shows it could exacerbate long-term warming and is therefore highly inadvisable at global scales."

 

 

 

 

Read more at:  http://spectrum.ieee.org/nanoclast/semiconductors/materials/graphene-promises-a-millionfold-increase-in-data-storage-capacity   

 

Rutgers Univ. chemistry Profs. Martha Greenblatt and Charles Dismukes in a laboratory on the Busch Campus in Piscataway. Photo: Nick Romanenko/Rutgers Univ.

New research published by Rutgers Univ. chemists has documented significant progress confronting one of the main challenges inhibiting widespread utilization of sustainable power: Creating a cost-effective process to store energy so it can be used later.

"We have developed a compound, Ni5P4 (nickel-5 phosphide-4), that has the potential to replace platinum in two types of electrochemical cells: electrolyzers that make hydrogen by splitting water through hydrogen evolution reaction (HER) powered by electrical energy, and fuel cells that make electricity from combining hydrogen and oxygen," said Rutgers chemistry Prof. Charles Dismukes. "Platinum is the benchmark material for both devices as it has the best conversion efficiency. However, while platinum may be acceptable for making jewelry and low volume specialty applications, it is too expensive for large-scale applications such as energy storage and conversion. Our new HER catalyst, Ni5P4, has the strong potential to overcome this challenge."

Rutgers chemistry Prof. Martha Greenblatt, Dismukes and colleagues published their findings on the patent-pending technology in Energy & Environmental Science.

"Scientists have been working for years to develop low-cost replacements for platinum and other noble metals used in these devices," Greenblatt said. "Ni5P4 is the most promising new material presently available that combines both the energy conversion efficiency of noble metals, yet is much more affordable based on the high natural abundance of its elements-over a million times greater than platinum."

The researchers believe that Ni5P4 should lower the material costs of both electrolyzers and fuel cells, while maintaining the efficiencies of these technologies for electrical conversion. "These devices are two key technological advances that could open the door to renewable fuels produced from sustainable feedstocks-water and sunlight," Dismukes said.

The next step for the research is to test the operating stability and efficiency of the compound over extended time periods in commercial electrolyzers and fuel cells. As these devices have different requirements for operation, independent tests for both will be needed. Rutgers has partnered with Proton OnSite of Wallingford, Conn., a commercial manufacturer of electrolyzers, to test Ni5P4 as an appropriate HER catalyst.

To achieve the overall water splitting process, the HER catalyst cathode will be combined with an oxygen-evolving (OER) catalyst anode. The Rutgers team has previously developed a noble-metal-free OER catalyst-LiCoO2 (lithium cobalt oxide)-that has shown promising performance in preliminary tests at Proton OnSite.

"If used together, these catalysts could eliminate the need for expensive noble metal based electrode materials," Greenblatt said.

 

 

Read more at:  http://www.rdmag.com/news/2015/03/study-holds-great-promise-advancing-sustainable-energy?et_cid=4473369&et_rid=614174443&type=cta 

 

NIST's new silver nanoparticle reference material is designed for extended shelf life to support environmental health and safety studies.

(Nanowerk News) The National Institute of Standards and Technology (NIST) has issued a new silver nanoparticle reference material to support researchers studying potential environmental, health and safety risks associated with the nanoparticles, which are being incorporated in a growing number of consumer and industrial products for their antimicrobial properties. The new NIST test material is believed to be the first of its kind to stabilize the highly reactive silver particles in a freeze-dried, polymer coated, nanoparticle cake for long-term storage.

 

Read more at:  http://www.nanowerk.com/nanotechnology-news/newsid=39273.php 

 
Reference link: https://www-s.nist.gov/srmors/view_report.cfm?srm=8017

NIST's new silver nanoparticle reference material is designed for extended shelf life to support environmental health and safety studies.

(Nanowerk News) Researchers in South Korea have, for the first time, developed a simple technique to produce a two-dimensional nitrogen-containing crystal that has the capacity to be a potential rival to graphene and silicon as semi-conductor materials (Nature Communications, "Nitrogenated holey two-dimensional structures").

Graphene is a two-dimensional (2D) one-atom-thick sheet of carbon crystals that has many extraordinary properties in terms of its strength, electrical and thermal conductivity, and optical transparency. Graphene shows promise for use in nanoelectronics, hydrogen storage, batteries and sensors. Research on graphene in recent years has raised huge interest among scientists about the potential of synthesising other 2D crystals by introducing elements other than carbon into graphene's carbon lattice. The motivation behind this is the possibility this might provide to develop materials that can be used as an active switching element in electronics.

The atomic size and structure of nitrogen make it an excellent choice for this purpose because it can fit naturally into a strong network of carbon atoms by creating bonds (sp2) in which electrons are shared by the whole network.

Whereas there are many difficulties in the synthesis of graphene, the team of researchers at Ulsan National Institute of Science and Technology (UNIST) and Pohang University of Science and Technology in South Korea synthesized nitrogenated 2D crystals using a simple chemical reaction in liquid phase without using a template. Conventional methods for the formation of 2D crystals require the use of such a template.

The researchers verified the structure of the nitrogenated crystal by atomic-resolution scanning tunnelling microscopy imaging and confirmed its semiconducting nature by testing it with a field effect transistor. The unique geometric and electronic structure of the nitrogenated crystals make it potentially suitable for use in electronics, sensors and catalysis. Its successful synthesis using a simple technique may open a new chapter in the cost-effective generation of other 2D materials.

 

Read more at: http://www.nanowerk.com/nanotechnology-news/newsid=39347.php  

 
Journal link: http://www.nature.com/ncomms/2015/150317/ncomms7539/full/ncomms7539.html#contrib-auth

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

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

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

"This is an abundant, renewable material that can be harvested from low-quality cellulose feedstocks already being produced in various industrial processes," said Pablo Zavattieri, an associate professor in the Lyles School of Civil Engineering.

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

Research findings were published in February in the journal Cement and Concrete Composites. The work was conducted by Jason Weiss, Purdue's Jack and Kay Hockema Professor of Civil Engineering and director of the Pankow Materials Laboratory; Robert J. Moon, a researcher from the U.S. Forest Service's Forest Products Laboratory; Jeffrey Youngblood, an associate professor of materials engineering; doctoral student Yizheng Cao; and Zavattieri.

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

"So, in essence, we are not using 100 percent of the cement," Zavattieri said.

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

 

Read more at: http://www.purdue.edu/newsroom/releases/2015/Q1/natural-nanocrystals-shown-to-strengthen-concrete-.html? 

 

 

Journal link: http://www.sciencedirect.com/science/article/pii/S095894651400211X

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