Researchers at the Helmholtz Institute for Pharmaceutical Research Saarland (HIPS) and the Helmholtz Centre for Infection Research in Braunschweig (HZI) are working on a project which could allow vaccinations to be administered via a skin cream.
The “taxis,” as Claud-Michael Lehr, director of the drug delivery department at HIPS, puts it, are biologically degradable nanoparticles.
The tiny transporters attach themselves to the hair follicles and so transmit the vaccination into the body, according to him.
“The skin is not broken,” says Lehr. “Ideally in the future you could simply put on some skin cream and you would be vaccinated.”
Such creams would be significantly cheaper to produce and simpler to administer, advantages which would be especially important for developing countries.
According to Ralph von Kiedrowski, regional director of the Association of German Dermatologists in Rheinland Palatinate, it is a method which is certainly workable.
There are already vaccinations which are absorbed via the lining of the mouth, he says.
Another advantage of administering drugs via a cream would be that it could be used for people who are afraid of needles, he says.
But the nanoparticles would have to consist of substances that would not cause an unintentioned reaction by the body’s immune system. And the packaging would have to be constructed in a way that the correct amount of the vaccination was used.
“It all depends on the correct dosage,” said Rolf Hoemke, spokesman for the Association of Research-Based Pharmaceutical Companies in Berlin. “But it must be possible to find a way of doing that with a cream.”
There are always thoughts of developing new methods of giving vaccinations without injections, he added, and a cream would be realistic.
The cream developed by the Helmholtz researchers is still in the pre-clinical phase, meaning it has only been tested in the laboratory and on animals.
A clinical study, which would involve people, is not being planned due to a lack of sponsors, says Lehr.
He believes that traditional vaccinations using injections have various disadvantages.
“It’s very laborious and expensive to produce such vaccinations and you need trained staff to administer it,” he explains.
Since the nanoparticles do not deliver enough of the vaccination to the body in order to create the desired effect on its immune system, the researchers have also funnelled so-called adjuvants through the skin via the transporters.
These chemical additives strengthen the immune response and are also used in traditional vaccines, according to Lehr.
The scientist believes that creams could also be used to treat people who suffer from allergies. – Sapa-dpa
24 Oct 2014
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Nanotechnology and Our Future
Nanotechnology has been called “The Next Industrial Revolution.” It will or already has, impacted almost every facet of our daily lives. From ‘Nano-Enabled’ Solar Energy & Storage, Nano-Enabled Water Filtraion & Remediation to ‘Nano-Enabled’ Drug Therapies for Cancer, Alzheimers and Diabetes – Nanotechnology will serve to advance our technology capabilities to meet the Vision for a Better Quality of Life for all of us who share this Planet Earth as ‘Home’.
Genesis Nanotechnology (GNT™) is an applied Nanotechnology Development Company. GNT™ acquires University developed ‘Nano-IP’ (Intellecutual Properties or Technologies), then develops; Patents, Trade Secrets & Processes for the commercialization of those technologies. Our areas of focus (our passions) are Clean, Renewable Energy and Clean, Accessible Water via ‘Nanotechnology’ – for our Planet – Our Home.
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With the installation of this first article (from the Financial Times) we will begin a series of articles addressing not only California’s “Water Disaster”, but the impact the lack of access to Clean, Abundant, Affordable WATER is having on our world – PLANET EARTH.
More importantly, we will address how we believe Nanotechnology with its many ‘cross disciplines’ across many Scientific Fields “holds the KEY” to solving the World’s Water Crisis. We believe that Nanotechnology and the need for water will also create commercial opportunities and the “Opportunity to Do Well … by Doing Good”. – Team GNT
“Nanotechnology and Desalinization – “An Answer to World’s Thirst for Water?”
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Our Foundational Technologies are in Water Filtration (including desalinization), Waste Water Remediation (including remediation of ‘Fracking Water’) and Mass Synthesis (production) of Nanomaterials that will enable new or replace existing technologies across a broad spectrum of mature Industries (Ex. – Textiles, Paints, Coatings, Inks, Solar, Electronics, Sensors, Water Filtration).
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Our GNT Team plans for the transition of “Developed Technology” into “Commercial Entities” even as we continue to work closely with our University Partners. While there are many ‘off ramps’ (‘Exit Strategies’) for the developed technologies, most will have a 3 to 5 Year Time Horizon, at which time our experience tells us that our ‘Investment Multiple’ ranges from 80:1 to 100:1. – “Doing Well … by Doing Good!”
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*** Note to Readers: With the installation of this first article (from the Financial Times) we will begin a series of articles addressing not only California’s “Water Disaster”, but the impact the lack of access to Clean, Abundant, Affordable WATER is having on our world – PLANET EARTH.
More importantly, we will address how we believe Nanotechnology with its ‘cross disciplines’ across many Scientific Fields “holds the KEY” to solving the World’s Water Crisis. We believe that Nanotechnology and the need for water will also create commercial opportunities and the “Opportunity to Do Well … by Doing Good”. – Team GNT
Next Week: “Nanotechnology and Desalinization – “An Answer to World’s Thirst for Water?”
(Story from the Financial Times: By Pilita Clark)
With his military fatigues and the holstered gun at his hip, Lieutenant John Nores Jr. is a slightly unnerving sight as he slips through the woody foothills overlooking the southern edge of California’s Silicon Valley. But what the 45-year-old game warden has come to look at is more alarming.
Here in the late summer heat, not far from the sleek headquarters of technology giants Apple and Google, he leads the way to a carefully hidden patch of terraced ground pockmarked with hundreds of shallow holes that until very recently contained towering marijuana plants.
California pioneered laws allowing marijuana use for medical reasons. But it has yet to follow states such as Colorado that permit recreational use and, in any case, this crop was on public land, making it illegal and dangerous to eliminate – Lt. Nores has witnessed several shoot-outs over the past decade.
He estimates that each of the state’s 2,000-odd cartel pot farms contains an average of 5,000 plants, and that each one sucks up between eight and 11 gallons of water a day, depending on the time of year. That means at least 80m gallons of water – enough for more than 120 Olympic-size swimming pools – is probably being stolen daily in a state that in some parts is running dry as a three-year-old drought shrinks reservoirs, leaves fields fallow and dries wells to the point that some 1,300 people have had no tap water in their homes for months.
Jerry Brown, California’s governor, declared a state of emergency in January after the driest year on record in 2013, but as the annual wet season beckons, the prospect of a complete drought recovery this winter is highly unlikely, government officials say.
“Marijuana cultivation is the biggest drought-related crime we’re facing right now,” says Lt Nores as he pokes at a heap of plastic piping the growers used to divert water from a dried-up creek near the plantation.
But California’s drought is exposing a series of problems in the US’s most populous state that are a reminder of an adage popularized by Michael Kinsley, the columnist: the scandal is often not what is illegal but what is legal.
The theft of 80m gallons of water a day by heavily armed marijuana cartels is undoubtedly a serious concern, not least when the entire state is affected by drought and 58 per cent is categorized as being in “exceptional drought”, as defined by the government-funded US Drought Monitor.
However, this is a tiny fraction of the water used legally every day in a state that, like so many other parts of the world, has a swelling population driving rising competition for more heavily regulated supplies that have long been taken for granted and may face added risks as the climate changes.
California has always been a dry state. For almost six months of the year many of its citizens get little rain. There have been at least nine statewide droughts since 1900, not counting the latest one.
The state’s history is littered with water wars, among them the conflicts surrounding Los Angeles’s move to siphon off most of the Owens river last century that inspired the classic 1974 film, Chinatown . That dispute was over just one part of a vast system of canals and reservoirs built in the last 100-odd years that are the reason California is sometimes called the most hydro-logically altered landmass on the planet.
The system channels water from wetter to drier spots, using rivers and streams that in a normal year fill with melted snow from mountain ranges ringing the state, supplying about a third of California’s farms and cities.
The crisis is more severe because a decline in snowfall has compounded problems caused by the lack of rain. The state’s mountain snowpack was just 18 per cent of its average earlier this year, a situation scientists say could be repeated as the climate warms.
As a result eight major reservoirs were last week holding less than half their average storage for this time of year. Reservoir levels sank worryingly when a bad drought hit California in 1976-77, but there were fewer than 22m people in the state then, compared with 38.3m now.
There were also fewer laws such as those protecting creatures such as the endangered Delta smelt, a finger-sized fish that can be affected by the management of the canal system, prompting restrictions on pumping the water used by a farming sector that accounts for nearly 80 per cent of the state’s human water use. Those laws regularly inflame debate between conservationists and farmers during droughts – and are doing so again today.
The farmer’s story
“I farm in a very environmentally conscious manner, but these regulations have made it much worse for the farmers,” says Barat Bisabri, a citrus and almond farmer whose property lies in the Central Valley, one of the regions worst hit by the drought.
This flat, fertile strip runs south for about 450 miles from the northern reaches of the Sacramento Valley through the heart of the state and grows a lot of what America eats. Nearly half the fruit and nuts grown in the US come from California, including 80 per cent of the world’s almonds.
An investigation into how businesses are having to adapt to rising water costs around the world
Much of that produce comes from the Central Valley, where farming is carried out on an industrial scale. Crops and orchards grow up to the edge of people’s houses. Driving down the valley’s long, straight roads, it is striking to see an orchard of dead, brown trees next to another with puddles of water around healthy ones.
This may partly be a symptom of a century-old water rights system that critics say is so weak and archaic it makes it hard for regulators to tell whose supplies should be cut during a drought.
Mr. Bisabri’s grim predicament shows why one study estimates the drought will cost the state $2.2bn in 2014.
From the windows of the roomy farmhouse that overlooks row upon row of the property’s citrus trees, Mr Bisabri points to two of California’s main waterways, the Delta-Mendota Canal and the California Aqueduct. Both run straight through his farm but because of the drought, authorities have sharply limited the amount of water many users can take from them.
“Unfortunately we cannot get water from either of them this year,” says Mr Bisabri, as he explains how, a few weeks earlier, he used bulldozers to rip out 85 acres of healthy mandarin, orange and grapefruit trees that would have used so much water it would have made the rest of the crop far less valuable.
“I had to make a decision to kill some so the other ones could survive,” he says, as he drives to the bare patch where the trees once stood. “Had I not made that decision and kept all the citrus that we had, then I would have run out of water in the middle of August.” It is a dilemma facing farmers across the Central Valley, many of whom have shifted from crops such as tomatoes or peppers to more valuable almonds or other trees that cannot be left unwatered in a dry year.
Perennial crops such as nuts and grapes accounted for 32 per cent of the state’s irrigated crop acreage in 2010, up from 27 per cent in 1998. The shift has been even more marked in the southern Central Valley, so when drought hits, farmers face difficult choices.
A few miles down the road from his farm, Mr Bisabri stops at a jaw-dropping sight by an almond orchard of withered trees: a huge earthmoving machine is scooping up several at a time and feeding them into another machine that grinds them with an ear-splitting roar into great mounds of woodchip.
“That is exactly the same machine that we used on my farm,” he says.
Mr Bisabri has had to bring in water from other sources this year, but he says the price was almost $1.2m, 10 times what it was the previous year.
That does not include the $250,000 he spent on digging new wells to try to get supplies from the one source farmers and communities have always turned to in times of drought: groundwater.
In a normal year, aquifers supply about a third of the state’s water. In a drought, that can rise to as much as 60 per cent. But one of the most alarming aspects of this drought is that groundwater levels are plummeting.
“Water levels are dropping at an incredibly rapid rate in some places, like 100ft a year,” says Michelle Sneed, a hydrologist with the US Geological Survey who monitors groundwater in the Central Valley. “It is very extreme. Ordinarily, talking with hydrologists, if you would talk about a well dropping 10ft a year that would really get somebody’s attention, like wow! Really? Ten feet? And now we’re 10 times that.”
The depletion of this vital resource is not just a concern because it is so difficult to refill some aquifers when drought eventually subsides. It is also creating extraordinary rates of subsidence because as the groundwater disappears the land above it can sink. In one part of the valley, land has been subsiding by almost a foot a year, which Ms Sneed says is among the fastest rates anywhere in the world.
This is damaging the very canal system California built to reduce reliance on groundwater, she says, because these waterways depend on gravity for a steady flow and when parts of a canal start sinking it creates a depression that needs more water to fill it before flows can resume.
‘We ran out of water in June’
Two hours’ drive south from Mr. Bisabri’s farm, the town of East Porterville has more pressing groundwater worries. At least 1,300 people in the town rely for drinking and bathing water on wells that have gone dry as the drought has deepened.
“We ran out of water in June,” says Donna Johnson, a 72-year-old retired counsellor who delivers water to dozens of dry households from the back of her pick-up truck. Ms Johnson depends on a hose running to her home from a neighbor whose well is still working.
Until now, California has been notable among dry, western states for a pump-as-you-please approach to groundwater. A powerful agricultural lobby resisted repeated attempts at reform.
But the severity of this drought finally led to a package of measures signed into law in September requiring local agencies to monitor and manage wells, or face state intervention. Some critics say it is too little too late: many local agencies will have five to seven years to come up with plans, and until 2040 to implement them. Still, it is a lot better than nothing, say others.
“It’s a giant step for California,” says Robert Glennon, a law professor at the University of Arizona and the author of Unquenchable: America’s Water Crisis and What To Do About It . “You cannot manage what you don’t measure, full stop.”
The crisis may also encourage approval of another measure to be voted on in November allowing billions of dollars to be borrowed for new reservoirs and other steps to strengthen drought resilience.
None of this will help farmers such as Mr. Bisabri or the residents of East Porterville this year. Still, it is one more example of how the state often responds to a serious drought, says Jay Lund, a water expert at the University of California, Davis.
“Every drought brings a new innovation where we say, ‘Oh, here’s something we haven’t been doing that would really be helpful’,” says Prof Lund, pointing to irrigation systems, reservoirs and water markets rolled out after past dry spells.
“In this drought, it’s groundwater regulation so far,” he says. And will it eventually work? “It opens the door.”
That is small comfort when the latest outlook from the US Climate Prediction Center suggests the drought “will likely persist or intensify in large parts of the state” this winter.
“If there’s no water for people to live, and you don’t have the basic necessities of life, your population is going to leave,” says Andrew Lockman, the emergency services manager responsible for East Porterville. “Our primary economic driver is agriculture. If there’s no water to water crops, we’re not going to have any agriculture business, so you could see the economy of this area just decimated.”
Next Week: “Nanotechnology and Desalinization – “An Answer to World’s Thirst for Water?”
Today’s electric vehicles, renewable energy storage, and many electronic gadgets are typically powered by lithium-ion batteries. The chemistry of lithium-ion batteries, however, limits how much energy they can store and this mature technology has reached its theoretical limit. Copyright By Michael Berger.
One promising alternative is the lithium-sulfur battery, which theoretically can hold as much as four times (2600 Wh kg-1) more energy per mass than lithium-ion batteries. The downside of lithium-sulfur batteries is that they have a much shorter lifespan because they can’t currently be charged as many times as lithium-ion batteries.
The abundance and environmentally friendly nature of the element sulfur as cathode material contributes to the huge potential of lithium-sulfur batteries. Researchers have already shown that a combination of nanocarbon and sulfur is an effective routine to overcome the insulating nature of sulfur for lithium sulfur batteries (read more: “Aligned carbon nanotube/graphene sandwiches for high-rate lithium-sulfur batteries” and “Nitrogen tunes carbon-sulfur interfaces for stable lithium-sulfur batteries“).
“Due to excellent electrical conductivity, mechanical strength and chemical stability, nanocarbon materials have been playing an essential role in the area of advanced energy storage,” Dr. Qiang Zhang, an associate professor at the Department of Chemical Engineering at Tsinghua University, tells Nanowerk. “However, most contributions concerning carbon/sulfur composite cathodes possessed a relatively low areal loading of sulfur of less than 2.0 mg cm-2, which prevents the full demonstration of the outstanding performance of C/S composite cathodes.
“The areal capacity of commercially used lithium-ion batteries is about 4 mAh cm-2, and therefore, the areal loading of sulfur in the cathode of lithium-sulfur batteries needs to be greatly improved,” adds Qiang. Zhang and his collaborators have now created a free-standing carbon nanotube paper electrode with high sulfur loading for lithium-sulfur batteries. As the team reports in Advanced Functional Materials (“Hierarchical Free-Standing Carbon-Nanotube Paper Electrodes with Ultrahigh Sulfur-Loading for Lithium–Sulfur Batteries”), they employed a bottom-up strategy to design and fabricate a hierarchical structure.
Schematic illustration of the hierarchical, free-standing electrode with ultrahigh sulfur-loading capability via a facile bottom–up approach. Red and purple spheres represent lithium ions and electrons, respectively. (Reprinted with permission by Wiley-VCH Verlag)
The team selected carbon nanotubes (CNTs) – one of the most efficient and effective conductive fillers for electrodes – as the building block. They used short multi-walled CNTs (MWCNTs) with lengths of 10-50 µm as the short-range electrical conductive network to support sulfur, as well as super-long CNTs with lengths of 1000-2000 µm from vertically aligned CNTs (VACNTs) as both long-range conductive networks and inter-penetrated binders for the hierarchical free-standing paper electrode.
“We have developed a bottom-up routine in which sulfur was first well dispersed into the MWCNT network to obtain MWCNT@S building blocks and then MWCNT@S and VACNTs were assembled into macro-CNT-S films via the dispersion in ethanol followed by vacuum filtration,” Zhe Yuan, a graduate student working with Zhang, and the paper’s first author, explains. “These sulfur electrodes with hierarchical CNT scaffolds can accommodate over 5-10 times sulfur compared to conventional electrodes on metal foil current collectors while maintaining the high utilization level of sulfur.”
In most reported Li-S cells, aluminum foil was used as current collector and a routine slurry-coating procedure was widely used during fabrication. This resulted in a ratio of 10-50 wt % of binders, conductive agents, as well as modifying precursors in the electrode, which neutralized the advantage of a Li-S system with high specific capacity.
This new fabrication method by the Tsinghua team does not employ aluminum foil or binders. “With our CNT paper electrodes we were able to achieve an initial discharge capacity of 6.2 mAh cm-2 (995 mAh g-1), a 60 % utilization of sulfur, and a slow cyclic fading rate of 0.20 %/cyc within the initial 150 cycles at a low current density of 0.05 C,” Jia-Qi Huang, a co-author of the paper, points out. “The areal capacity can be further increased to 15.1 mAh cm-2 by stacking three CNT-S paper electrodes, with an areal sulfur loading of 17.3 mg cm-2 as the cathode in a Li-S cell.”
High areal capacities of stacked lasagna-like structured electrodes: cycling performance (with insets depicting the corresponding electrode structures). (Reprinted with permission by Wiley-VCH Verlag)
“Our proof-of-concept experiment indicates that the rational design of the nanostructured electrode offers the possibility to efficiently use the active materials at practical loading,” says Zhang. “The current bottom-up electrode fabrication procedure is effective for the preparation of large-scale flexible paper electrodes with a good distribution of all functional compounds; this procedure is also potentially applicable to graphene, CNT-graphene, and CNT-(metal oxide)-based flexible electrodes.” This free-standing paper electrode offers the possibility of ubiquitous applications of Li-S batteries at a low cost and at high energy densities for future flexible electronic devices.
As sustainability has increasingly become a central focus in many sectors of the global economy, manufacturers are constantly striving to increase efficiency in terms of energy, weight, emissions and generally reducing their environmental footprint.
Those requirements are the primary drivers behind the widespread adoption of composite materials.
Composite “materials” are created when two or more different materials are arranged together according to a microstructure (i.e. the way these materials are arranged together in space). The properties at large scale are intimately related to this microstructure. In other words, starting from the same raw materials but engineering different microstructures can result in completely different behaviors.
That makes this field full of opportunities for optimizing and tailoring the material to the application. When not only the mechanical behavior is considered, but multiple physics together (thermal, electrical) as well as the coupling between them, such materials can be engineered to obtain the complex behaviors needed for achieving multifunctional structures.
Composites are found in sports equipment, buildings, aircraft manufacturing, and the energy sector to name a few. Latest generation composite aircraft, for instance, can have a gain of around 25% efficiency compared to the same metallic design. Composites pipes can be used to make water or oil transportation infrastructures insensitive to corrosion and to reduce the pollution of the conveyed product.
As most common composites make use of carbon, they are often referred as “black metal”. They have of course nothing to do with more classical metallic materials, but this expression well stresses the potential of these materials to become the most popular candidates for large-scale engineering. Yet, we are only at the beginning of the “black metal” revolution.
“Today we are very good at making composite structures; the main problem is how they are going to evolve in time,” says Gilles Lubineau, Associate Professor of Mechanical Engineering at KAUST and Principal Investigator of the Composite and Heterogeneous Materials Analysis and Simulation Laboratory (COHMAS). That means it’s possible to employ innovative composite structure technology to manufacture versatile aircrafts, windmill blades, and industrial pipes — but the big question is ensuring their “stability and service lifetime.”
Prof. Lubineau and his group’s research thrust essentially focuses on computational modeling and experimental developments to tackle complex problems related to composite engineering. In the group, new materials are developed to meet new challenging operational conditions, techniques are being developed to understand their behavior, monitor their integrity, and computational approaches are being put in place to make possible the prediction of the relations between microstructure, functionality and durability.
Optimizing the microstructure to achieve the best performance
Successfully capturing the structural properties and optimal functionality of composite and heterogeneous materials requires a multi-faceted set of skills. The COHMAS team is split 50 percent with experts in computational mechanics while the other 50 percent has an expertise in experimental mechanics.
One of the particularities of Professor Lubineau’s team, part of the mechanical engineering program and specializing in a wide variety of composite materials, is to bring together people with very different backgrounds, ranging from mechanical engineering, applied mathematics, and theoretical mechanics to material science and chemical engineering.
“This wide variety of background makes the team able to tackle real composite problems that are necessarily multiphysics and multiscale problems. This also makes the team capable of theoretically designing the microstructure to reach the best performance, and then to synthesize it and explore it from the experimental point of view; this ability is quite rare in a single group,” Prof. Lubineau says.
The background of the team being primarily Mechanical Engineering and not Material Science, “we look at the material more from a structural point of view and this completely changes the approach” as Lubineau explains. The COHMAS team sees the material as a structure or as something that is part of a structure.
For illustration purposes, Prof. Lubineau takes the example of an aircraft: “The stresses, strains and everything is very heterogeneous. So it becomes necessary to accommodate the gradients in order to optimize materials at the critical locations in the aircraft’s structure.”
Doing so, Prof. Lubineau’s group has recently design highly conductive polymer fibers with controlled conductivity and piezoresistivity. “Such fibers will help in creating new self sensing and multifunctional structures and fast-response heating components in wearable textiles. They are the building blocks for better functional integration which serves cost reduction, energy efficiency and improved conductivity in service,” said Prof. Lubineau. “This has been made possible only by people with very different backgrounds working together towards a common goal”.
Prof. Lubineau’s group also works on composite materials destined for large industrial pipes, five or six meters in diameter, used for oil or water transportation. Particularly in arid regions like in Saudi Arabia, these pipes can experience high levels of degradation and specific aging conditions due to the extreme environmental conditions. Here again, understanding how the microstructure drives the final performance is key to process and design optimization.
Predicting and monitoring integrity
Material design is important, but understanding how the material is going to evolve in time is at least as crucial. A material might have tremendous properties, and be totally useless if these cannot be sustained at long term in a real working environment.
Among the multitude of factors that need to be considered are: mechanical degradation, aging, coupling with environments.
“You need to be able to predict what will happen in thirty years based on experiments that cannot last for more than a few weeks or a few months. What we want to achieve is more than a classical phenomenological model. We need models that can be use for making predictions with trust, models that can be use for design and exploration of new solutions,” Lubineau said.
Predictive science, with a physics based description of experimental observations later formalized in rigorous models, is then essential to Prof. Lubineau’s group. They have been engaged in designing models for many advanced structures while at Kaust, ranging from composite fuselage integrity to pipes integrity in sour environment.
Prof. Lubineau stresses that the objective is not to replace accelerated testing that is usually the preferred choice in industry (that means subjecting the structure to harsher condition during a shorter time to predict long term degradation).
“The objective of predictive testing is first, to design relevant accelerated testing conditions that are actually representative of what will happen at long term, and to understand the physics well enough to develop techniques for structural health monitoring (SHM),” said Prof. Lubineau.
“Monitoring composites is a real challenge today. Practical technologies are investigated to provide the most efficient and reliable real time monitoring such as optical fiber sensing (with Fiber Bragg Gratings) or electrical impedance/resistivity tomography (EIT/ERT). Thanks to these detection methods more challenging engineering may be envisaged through the design of preventive maintenance strategies.” His team is then investigating how such reliable models can be used for better SHM techniques. Successes have already been met for impedance based monitoring for example.
Computational techniques for better design of Composite structures
A last axis of Prof. Lubineau’s group is the design of adequate computational techniques to predict the integrity of complex structures such as composite made structures.
Prediction of crack propagation in such complex media is particularly challenging. Yet, this is a real industrial need.
“A crack is first of all a discontinuity, and continuum mechanics does not like discontinuities. It makes simulations much more complex and sometimes intractable with current technologies when many of them are involved,” said Prof. Lubineau.
He developed with Boeing a successful technique called “morphing”, published in Journal of the Mechanics and Physics of Solids, in which non-local continuum mechanics can be efficiently glued with classical continuum mechanics. “This provides a natural framework for computing crack nucleation and extension. This is still in its infancy, but we believe a promising technique in the future” adds Prof. Lubineau
Collaborations with Industry
Most of Prof. Lubineau’s research at COHMAS is done in close collaboration with major industrial partners such as Boeing, Sabic, Aramco or Amiantit. The applied research and advanced theoretical concepts are directly tested and applied to concrete problems.
Despite the variety of these projects, they are all related to the application of advanced composite material to some real application such as composite fuselage, composite pipes, composites for civil engineering or the automotive industry. The team helps in bridging the gap between theoretical knowledge and the real application of these materials.
Saudi Arabia is already a major player as a provider of the raw products. But Prof. Lubineau foresees an expanded future role for the Kingdom where, instead of just selling the raw material, Saudi Arabia could directly sell technologies with the more advanced derived material at a much higher added value. “This can really play a role in developing the local economy.”
At first glance, the static, greyscale display created by a group of researchers from the Hong Kong University of Science and Technology, China might not catch the eye of a thoughtful consumer in a market saturated with flashy, colorful electronics.
But a closer look at the specs could change that: the ultra-thin LCD screen described today in a paper in The Optical Society’s (OSA) journal Optics Letters is capable of holding three-dimensional images without a power source, making it a compact, energy-efficient way to display visual information.
Liquid crystal displays (LCDs) are used in numerous technological applications, from television screens to digital clock faces. In a traditional LCD, liquid crystal molecules are sandwiched between polarized glass plates. Electrodes pass current through the apparatus, influencing the orientation of the liquid crystals inside and manipulating the way they interact with the polarized light. The light and dark sections of the readout display are controlled by the amount of current flowing into them.
Credit: Optical Society of America
The new displays ditch the electrodes, simultaneously making the screen thinner and decreasing its energy requirements. Once an image is uploaded to the screen via a flash of light, no power is required to keep it there. Because these so-called bi-stable displays draw power only when the image is changed, they are particularly advantageous in applications where a screen displays a static image for most of the time, such as e-book readers or battery status monitors for electronic devices.
“Because the proposed LCD does not have any driving electronics, the fabrication is extremely simple. The bi-stable feature provides a low power consumption display that can store an image for several years,” said researcher Abhishek Srivastava, one of the authors of the paper.
The researchers went further than creating a simple LCD display, however —they engineered their screen to display images in 3D. Real-world objects appear three-dimensional because the separation between your left eye and your right creates perspective. 3D movies replicate this phenomenon on a flat screen by merging two films shot from slightly different angles, and the glasses that you wear during the film selectively filter the light, allowing one view to reach your left eye and another to fall on your right to create a three-dimensional image.
However, instead of displaying multiple images on separate panels and carefully aligning them—a tedious and time-consuming process—the researchers create the illusion of depth from a single image by altering the polarization of the light passing through the display. They divide the image into three zones: one in which the light is twisted 45 degrees to the left, another in which it is twisted 45 degrees to the right, and a third in which it is unmodified. When passed through a special filter, the light from the three zones is polarized in different directions. Glasses worn by the viewer then make the image appear three-dimensional by providing a different view to each eye.
This technology isn’t ready to hit the television market just yet: it only displays images in greyscale and can’t refresh them fast enough to show a film. However, Srivastava and his colleagues are in the process of optimizing their device for consumer use by adding color capabilities and improving the refresh rate. The thin profile and minimal energy requirements of devices could also make it useful in flexible displays or as a security measure on credit cards.
22 Oct 2014
UC Irvine technologists have produced a nanotechnology device that can detect lung infections. The project was led by Regina Ragan and electrical engineer Filippo Capolino. According to Controlled Environments, the device is a nano-optical sensor that can detect tiny quantities of infection in a small sample of breath. As well as diagnosing medical conditions, the device can potentially detect air pollution.
The primary aim is as an early warning sign for people with cystic fibrosis. Cystic fibrosis is an autosomal recessive genetic disorder that affects mostly the lungs but also the pancreas, liver, and intestine. Suffers are at a risk from developing lung infections, and here infections can cripple the lungs further or even result in death. Most people with cystic fibrosis are on antibiotics at all times, even when healthy, in order to suppress infection.
The device was developed through a $1.3 million grant from the National Science Foundation. The importance of such a device is that knowledge of a lung infection would let people with cystic fibrosis seek immediate treatment and thereby prevent permanent damage occurring to their lungs.
At present, only a prototype has been built. The developers are working out how to create a device that can be produced on a commercial scale. The complications are around the nano-scale technology and with making the device cost-effective.
In related news, scientists from Denmark have demonstrated precisely how bacteria can grow directly in the lungs of cystic fibrosis patients. This insight into bacteria behavior and growth in chronic infections should help with treatment.
Conventional solar cells exhibit limited efficiencies in part due to their inability to absorb the entire solar spectrum. Sub-band-gap photons are typically lost but could be captured if a material that performs up-conversion, which shifts photon energies higher, is coupled to the device.
Recently, molecular chromophores that undergo triplet–triplet annihilation (TTA) have shown promise for efficient up-conversion at low irradiance, suitable for some types of solar cells. However, the molecular systems that have shown the highest up-conversion efficiency to date are ill suited to broadband light harvesting, reducing their applicability.
Here we overcome this limitation by combining an organic TTA system with highly fluorescent CdSe semiconductor nanocrystals. Because of their broadband absorption and spectrally narrow, size-tunable fluorescence, the nanocrystals absorb the radiation lost by the TTA chromophores, returning this energy to the up-converter. The resulting nanocrystal-boosted system shows a doubled light-harvesting ability, which allows a green-to-blue conversion efficiency of ∼12.5% under 0.5 suns of incoherent excitation. This record efficiency at subsolar irradiance demonstrates that boosting the TTA by light-emitting nanocrystals can potentially provide a general route for up-conversion for different photovoltaic and photocatalytic applications.
Wearable computing is lauded as the next evolution of computing and interactivity. Today this is manifesting in the market with “smart” watches and displays and the first wave of “smart glasses.” The next step in wearable computing is in “smart” clothing, i.e. fabrics integrated with various electronics and computing components and energy harvesting, and even fabrics that incorporate some of those capabilities themselves. Some clothing that could be plausibly considered “smart” has been available for years, essentially as a niche market.
NanoMarkets sees this category poised to emerge into the spotlight and becoming a significant revenue generator for various levels in the supply chain, from materials suppliers to retailers. The key lies in the progress of development and commercialization of new and improved fabrics and sensors that are the essential building blocks for the capabilities — and value — of various smart clothing products.
Three main barriers historically have been, and continue to be, at the center of development for “smart clothing” to pave the way for mass adoption:
- improved connectivity between modules,
- improved washability of smart fabrics, and s
- standardized protocols.
Thus, here also lies the opportunity for both materials and sensor manufacturers to develop new and improved types of smart fabrics and sensors: from lighter, soft flexible sensors to functional fabrics, conductive polymers, and even fibertronics that can function without the need for sensors.
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21 Oct 2014
From the newly released NanoMarkets report, “Materials for Next-Generation Photovoltaics – 2014-2021”
The solar panel industry now seems back on track following the boom-and-bust period. It’s still a sector dominated by crystalline silicon, but the current upswing means that the search is on once more for materials platforms that improve the conversion efficiency of solar panels, and efforts have been rebooted to hone and ultimately commercialize these next-generation materials.
Some of them are close at hand, such as novel approaches to doping silicon panels. Meanwhile, the thin-film PV sector continues to seek success against entrenched c-Si; this could come from improvements to CdTe and CIGS, while other thin-film materials are beginning to receive serious commercial attention.
The solar industry also is beginning to think out of the box with a slew of entirely new nanomaterials such as quantum dots, nanowires, nanotubes and graphene.
Here’s a rundown of what we see emerging in next-gen solar PV materials:
Opportunities in Silicon Photovoltaics
The need for better c-Si technology has urged a more aggressive roadmap based on advanced c-Si technologies. Prominent ones gaining traction include n-type cells, back-contact cells, selective emitter options, wrap-through variants, and cells with rear side passivation. We anticipate a scale-up to volume production is likely to occur 2015, when investments are expected to pick up — we currently see the materials market value for advanced c-Si racing ahead from just $16 million in 2014 to $115 million in 2016, and topping $1.5 billion by 2020.
Compared with standard and matured p-type c-Si technology, n-type Si offers better tolerance to common impurities, higher device lifetime, and lesser light-induced degradation, though further research is needed to eliminate non-uniform electrical resistivity and to come up with more effective passivation techniques for charting out a sizable, and cost-effective, production route. Among the potential n-type substrates, PERT, HJ and IBC cell architectures are likely to be investigated further. Wafer thinning (and new ultra-thin wafers), multiple-junction structures, screen printing, and ion implantation also can be routes to develop high-efficiency n-type solar cells.
Although suppliers in Taiwan, the U.S., and Europe have shown signs of adopting higher efficiency c-Si technology, greater adoption in Japan and bigger involvement of Chinese players will be significant to facilitate the migration of standard c-Si technologies to the advanced forms.
Next-generation thin-film PV
Standard thin-film PV has found it hard to compete with conventional c-Si’s relentless cost cuts, pricing pressure, and efficiency improvements. Part of the answer for thin-film PV lies in multi-junction PV cells to utilize more of the available solar spectrum; other avenues include addressing markets where c-Si has disadvantages, such as certain low-light and hot outdoor environments, and in building-integrated photovoltaics (BIPV). Given the ambitious roadmaps of the two thin-film leaders First Solar and Solar Frontier, we expect 2015 could witness active commercial developments as the cost difference between the standard C-Si and existing thin-film technologies narrows. This is especially important as the solar industry shifts toward remote and unsubsidized markets.
Various thin-film technologies are being pursued. CdTe PV cells currently pose a strong challenge to multi-Si cells in terms of efficiency, and should find acceptance in constrained spaces and other related industrial applications — novel and cost-effective approaches for doping, back-contact formation, and printing will be key. Commercial progress with CIGS has been slow due to processing complexities and encapsulation concerns, but in terms of efficiency CIGS is now tantalizingly close to that of single-crystal PV, and new production approaches and methodologies illuminate a path to beat Si-based PV technologies in cost terms. Other emerging thin-film candidates include CZTS (a CIGS variant with a different absorber material), CdMgTe (a II-VI semiconductor alloy), and pyrites.
Collectively, NanoMarkets sees emerging thin-film PV as fledgling in the near term, cracking the $120 million barrier at the far end of our eight-year forecast window (2021).
OPV and DSC
Organic photovoltaic (OPV) cells have been the focus of much research as they are lightweight, flexible, inexpensive, highly tunable, and potentially disposable. Their main advantage is a very high absorption coefficient coupled with the use of low-cost, high-throughput manufacturing techniques (such as inkjet printing and roll-to-roll). Despite the improving performance of OPV cells, there are urgent needs to address: develop large-area monolithic panels, reduce defect density and improve yields, and devise better encapsulation systems to improve OPV module lifetime to at least 10 years.
We think OPV modules need to demonstrate closer to 8% efficiency level and 10 years of lifetime — and ultimately module production costs to below $0.50/watt — within the next five years’ time to be competitive in the marketplace, first in DC portable power devices followed by building integrated PV (BIPV) applications. Part of this will involve commercialization efforts through industry joint collaborative projects, and a specific OPV material-related IP ecosystem with a sea of change of newer players bringing out new materials, such as narrow optical gap photoactive polymers.
Perhaps the most excitement around solar PV materials is around perovskite, which in just a few short years has enjoyed a trajectory of efficiency improvements unlike any other solar PV material — from breaking the 10% barrier in 2012 to 15% in 2013 and nearly 20% already this year, and likely as high as 30% before being commercially rolled out. NanoMarkets sees very important ramifications from perovskite’s unprecedented trajectory for one specific market segment: dye-sensitized solar cells (DSC). Several key DSC firms already have been at the forefront of the perovskite solar revolution. A great deal of research continues into perovskite materials optimization and processing techniques. We believe it is indeed possible that perovskite PV cells could quickly ramp to and beyond the 20% mark and compete against the more established Si counterparts within the next several years.
NanoMarkets sees enough positive signs from this segment of emerging PV — OPV, DSC, and perovskite — that we think it could begin to rival that of aforementioned advanced c-Si by the end of our forecast period, topping $1.1 billion in materials market value.
Nanomaterials for Next-generation PV
Further along the solar PV technology roadmap are a number of nanomaterials which present various attractive options, and challenges that continue to slow their development toward commercialization anytime soon:
– Silver nanowires offer the potential to replace traditional electrode materials due to their intriguing electrical, thermal, and optical properties: an inherent low resistivity, high specular transmittance, superior flexibility, and surface plasmon resonance effect. Despite substantial progress, however, they have yet to find use in commercial use as efficient transparent electrodes that can boost energy conversion efficiency to realistic levels, still demonstrating efficiency below 10%.
– Quantum dots are considered as one of the most attractive candidates for solar PV, thanks to inexpensive low-temperature solution processing techniques and a theoretical energy conversion efficiency of up to 45%. Actual efficiency, however, is still below 10%, so commercial viability is still a long way off — but put another way, there’s still a lot of room for improvement, including ways to pair QDs with other suitable PV materials as co-absorbers in PV cells
– Carbon nanotubes (CNT) are gaining broad interest for their unique properties which can be used effectively for photovoltaic solar cells: easy and inexpensive to manufacture, stable and durable, and both good light absorbers and electrical conductors. CNTs have shown PV cell energy conversion efficiency of up to 80% via an efficient charge transport mechanism inside the cell, and recent advances allow greater level of control over their chemical makeup. In fact CNTs could be on track to be commercially ready before quantum dots — but that’s a relative assessment, because we feel they’re still unlikely to be commercialized for PV applications anytime soon.
– Which brings us to the ever-next-gen material, graphene, which in the case of PV applications has shown promise as absorber and photoactive layer with extreme conductivity and transparency, plus an affinity to keep its properties even after being coated with another conductive material (e.g. silicon or copper). Research initiatives around the use of graphene in PV applications have shifted from treating graphene as a substitute for ITO (in transparent electrodes) to viewing it as a potential conduction layer candidate in the next generation of PV cells. There is a possibility of using it in combination with titanium dioxide as a charge collector, keeping perovskite material as the sunlight absorber in PV cells. Under such an arrangement, cell efficiency of 15.6% has been achieved.