New breakthrough in battery charging technology

A team of researchers, affiliated with UNIST has developed a single-unit, photo-rechargeable portable power source based on high-efficiency silicon solar cells and lithium-ion batteries (LIBs). This newly-developed power source is designed to work under sunlight and indoor lighting, allowing users to power their portable electronics anywhere with access to light. In addition, the new device could power electric devices even in the absence of light. In this work, the team of Professor Sang-Young Lee and Professor Kwanyoung Seo of Energy and Chemical Engineering at UNIST presented a new class of monolithically integrated, portable PV-battery systems (denoted as 'SiPV-LIBs') based on miniaturized crystalline Si photovoltaics (c-Si PVs) and printed solid-state lithium-ion batteries (LIBs). The device uses a thin-film printing technique, in which the solid-state LIB is directly printed on the high-efficiency c-Si PV module. "This device provides a solution to fix both the energy density problem of batteries and the energy storage concerns of solar cells," says Professor Lee. "More importantly, batteries have relatively high power and energy densities under direct sunlight, which demonstrates its potential application as a solar-driven infinite energy conversion/storage system for use in electric vehicles and portable electronics." According to the research team, this single-unit PV-LIB device exhibits exceptional photo-electrochemical performance and design compactness that lie far beyond those achievable by conventional PVs or LIBs alone. It also displays unprecedented improvements in photo-charging (rapid charging in less than 2 min with a photo-electric conversion/storage efficiency of 7.61%). In the study, the research team fabricated a solid-state LIB with a bipolar cell configuration directly on the aluminium (Al) electrode of a c-Si PV module through an in-series printing process. To enable the seamless architectural/electrical connection of the two different energy systems, the Al metal layer is simultaneously used as a current collector of the LIB, as well as an electrode for solar cells. This allows the battery to be charged without the loss of energy. Professor Seo and his team have successflly implemented lossless c-Si PV modules by designing rear electrode-type solar cells. Using single-junction solar cells to fabricate solar cell modules may cause energy loss, which can be prevented by the rear electrode-type design. They also simplified the manufacturing process, using the small solar cell arragements formed on a single Si substrate substrate. In the study, Professor Lee and his research team connected the device to various portable electronics to explore its practical use. They fabricated a monolithically integrated smartcard by inserting the SiPV-LIB device into a pre-cut credit card. Then, electric circuits were drawn on the back of the credit card using a commercial Ag pen to connect the SiPV-LIB device with an LED lamp. The SiPV-LIB device was also electrically connected with a smartphone or MP3 player and its potential application as a supplementary portable power source was explored under sunlight illumination. The SiPV-LIB device was capable of fully charging under sunlight illumination after only 2 min. It also showed decent photo-rechargeable electric energy storage behaviour even at a high temperature of 60°C and even at an extremely low light intensity of 8 mWcm-2, which corresponds to the intensity in a dimly-lit living room. "The SiPV-LIB device presented herein shows great potential as a photo-rechargeable mobile power source that will play a pivotal role in the future era of ubiquitous electronics," says Professor Lee. The results of the study will be featured on the front cover of the April 2017 issue of the world-renowned journal Energy & Environmental Science (EES). This work has been supported by the Basic Research Program and the Wearable Platform Materials Technology Center through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT & Future Planning (MSIP). It was also supported by the Development Program of the Korea Institute of Energy Research (KIER).   Story Source: Materials provided by Ulsan National Institute of Science and Technology(UNIST). Note: Content may be edited for style and length.

This Hack Will Forever Change the Way You Make Grilled Cheese

It sounds pretty obvious: adding more cheese to grilled cheese will make it better. But it turns out that where you put the cheese might have more of an impact than how much cheese you add. I learned this trick recently when I got a demo of the Cinder, the world's first precision grill. If you're wondering what exactly that means, think of it as a really fancy panini press that can be used to sear steaks, sauté vegetables, make omelets and pancakes, and much more, and it cooks everything to your exact targeted temperature without the possibility of overcooking. And it makes one hell of a grilled cheese. When Cinder's CEO and founder Eric Norman started making a grilled cheese in my office, I was immediately intrigued by what he did: he buttered the bread and then not only sprinkled cheese in the middle of the bread, but he sprinkled it on top, too. Genius! I don't know why I never thought to do this before when making grilled cheese, but now I'm convinced it's the only way to go. What happens when the top half of the hot grill hits the cheese-covered slice of bread is the cheese melts onto the bread and the butter melts to create a golden-brown, crispy exterior. If you don't have a Cinder in your own kitchen, you can use a flat panini press to achieve the exact same results. And if you don't have either of those to work with, we think you can re-create the hack in a good-old nonstick skillet on the stovetop. (But disclaimer: we haven't tested that). Here's what we're thinking you can do: as your butter (or ghee, which is best for high-heat cooking) is sizzling over high heat, sprinkle your favorite cheese into the pan; we used a pizza blend with mozzarella and provolone. It'll form a melty bottom layer that you can add your slice of bread directly onto. Then add more cheese followed by the second slice of bread. Allow it to cook until the cheese crisps up into a caramelized crust. Flip the grilled cheese to finish searing the other side, and voila! You've got a grilled cheese topped with cheese. What more could you ask for in life? If you want to spice things up a little, try adding mushrooms — they basically become one with the bread, and they look adorable and taste delicious. However you decide to customize your own sandwich, one thing is for sure: you'll never go back to a "regular" grilled cheese again.   April 24, 2017 by ERIN CULLUM  

Nanoparticle vaccine shows potential as immunotherapy to fight multiple cancer types

Researchers from UT Southwestern Medical Center have developed a first-of-its-kind nanoparticle vaccine immunotherapy that targets several different cancer types. The nanovaccine consists of tumor antigens -- tumor proteins that can be recognized by the immune system -- inside a synthetic polymer nanoparticle. Nanoparticle vaccines deliver minuscule particulates that stimulate the immune system to mount an immune response. The goal is to help people's own bodies fight cancer. "What is unique about our design is the simplicity of the single-polymer composition that can precisely deliver tumor antigens to immune cells while stimulating innate immunity. These actions result in safe and robust production of tumor-specific T cells that kill cancer cells," said Dr. Jinming Gao, a Professor of Pharmacology and Otolaryngology in UT Southwestern's Harold C. Simmons Comprehensive Cancer Center. A study outlining this research, published online in Nature Nanotechnology, reported that the nanovaccine had anti-tumor efficacy in multiple tumor types in mice. The research was a collaboration between the laboratories of study senior authors Dr. Gao and Dr. Zhijian "James" Chen, Professor of Molecular Biology and Director of the Center for Inflammation Research. The Center was established in 2015 to study how the body senses infection and to develop approaches to exploit this knowledge to create new treatments for infection, immune disorders, and autoimmunity. Typical vaccines require immune cells to pick up tumor antigens in a "depot system" and then travel to the lymphoid organs for T cell activation, Dr. Gao said. Instead, nanoparticle vaccines can travel directly to the body's lymph nodes to activate tumor-specific immune responses. "For nanoparticle vaccines to work, they must deliver antigens to proper cellular compartments within specialized immune cells called antigen-presenting cells and stimulate innate immunity," said Dr. Chen, also a Howard Hughes Medical Institute Investigator and holder of the George L. MacGregor Distinguished Chair in Biomedical Science. "Our nanovaccine did all of those things." In this case, the experimental UTSW nanovaccine works by activating an adaptor protein called STING, which in turn stimulates the body's immune defense system to ward off cancer. The scientists examined a variety of tumor models in mice: melanoma, colorectal cancer, and HPV-related cancers of the cervix, head, neck, and anogenital regions. In most cases, the nanovaccine slowed tumor growth and extended the animals' lives. Other vaccine technologies have been used in cancer immunotherapy. However, they are usually complex -- consisting of live bacteria or multiplex biological stimulants, Dr. Gao said. This complexity can make production costly and, in some cases, lead to immune-related toxicities in patients. With the emergence of new nanotechnology tools and increased understanding of polymeric drug delivery, Dr. Gao said, the field of nanoparticle vaccines has grown and attracted intense interest from academia and industry in the past decade. "Recent advances in understanding innate and adaptive immunity have also led to more collaborations between immunologists and nanotechnologists," said Dr. Chen. "These partnerships are critical in propelling the rapid development of new generations of nanovaccines." The investigative team is now working with physicians at UT Southwestern to explore clinical testing of the STING-activating nanovaccines for a variety of cancer indications. Combining nanovaccines with radiation or other immunotherapy strategies such as "checkpoint inhibition" can further augment their anti-tumor effectiveness.     Story Source: Materials provided by UT Southwestern Medical Center. Note: Content may be edited for style and length.

Better living through pressure: Functional nanomaterials made easy

Using pressure instead of chemicals, a Sandia National Laboratories team has fabricated nanoparticles into nanowire-array structures similar to those that underlie the surfaces of touch-screens for sensors, computers, phones and TVs. The pressure-based fabrication process takes nanoseconds. Chemistry-based industrial techniques take hours. The process, called stress-induced fabrication, "is a new technology that mimics imprint processes already used by manufacturers," said Sandia researcher Hongyou Fan, who led the effort. "Only instead of embossing credit cards, we're using the same type of process to fabricate nanowires or other nano-sized components at ultrashort time scales." The method, for which three patents have been issued, is 9 million times faster than any known chemical method when performed on Sandia's Veloce pulsed-power machine, which generates pressures on the order of 100,000 atmospheres, said Fan's colleague, Jack Wise. Less exotically, for manufacturing instead of research, embossing machines similar to those already commercially in use could serve. "It's conceivable that few modifications would be needed to convert the machines from embossing to fabrication," Fan said. The Sandia process saves: time, because circuits can be fabricated in seconds instead of the hours required by chemical methods; the environment, because there's no chemical waste to clean up; materials, because exactly the amount needed is placed on a substrate. Also, defects common in industrial chemical fabrication of semiconductors are reduced in number by the pressure process, which acts to fill any vacancies occurring in the product's atomic lattice. "I have never seen or heard of this [process] in our extensive interaction with some of the leading material scientists in the world," said Tom Brennan of Chicago-based Arch Venture Partners, speaking in a video about an earlier version of the process. "It allows us to think of completely new material solutions to problems industry is facing across the board." That earlier version of the pressure-based process worked by using a hand-tightened vise with diamond anvils, but that tool was not rapid or malleable enough for commercial production. Industrial embossing machines, on the other hand, produce sufficient pressure and are controllable. "For a touch-screen, the pressure has to be worked out beforehand to stop the compression at just the right distance from the target: not too far, not too close, to produce the underlying nanowiring for a flat screen," said Fan. "It's a matter of programming the force applied to precisely determine how much to compress." That is, for flat screens, the nanowires need to be made flexible enough to contact an electrically charged layer of the device when pressed by a finger, yet far enough apart to remain separate when there's no signal. The technology, recently reported in Nature Communications, can fabricate a wide variety of nanoscale components including nanorods and nanosheets. The components can either be organized during their formation or dispersed in solvents for later assembly. The method could be used for chemical sensors, strain detectors and electrodes in solar cells. Sandia researcher Hongyou Fan has been appointed a National Laboratory Professor at the University of New Mexico's School of Engineering in its chemical and biological engineering department. The non-tenure-track appointment, which took effect March 1, automatically renews every three years and was made "in recognition of your significant achievements," according to the university's award notification. "I look forward to the opportunities for development of collaborative programs and student mentoring," said Fan.   Story Source: Materials provided by DOE/Sandia National Laboratories. Note: Content may be edited for style and length.

Robotic cheetah created

University of Twente researcher Geert Folkertsma has developed a prototype cheetah robot. Folkertsma has dedicated four years of research and development to constructing a scaled-down robotic version of the fastest land animal in the world, with a view to replicating its movements. Relatively speaking, the robot moves using only about fifteen percent more energy than a real cheetah. Folkertsma's doctoral defence of this unique project will take place on 21 April 2017 at the University of Twente. "As you might expect of the fastest land animal in the world, the cheetah makes very efficient use of its energy," Folkertsma explains. "I wanted to create a robot that runs the same way, with the aim of applying this knowledge to the development of new robots. Robots are bound to play an increasingly important part in our daily lives and we therefore have to ensure that they can move effectively in our environment. My robot vacuum cleaner, for example, cannot climb stairs or even cope with thresholds. We therefore need to develop robots that can walk and when it comes to moving around efficiently, there's a lot we can learn from the cheetah." While walking robots tend to be large and heavy, taking cumbersome steps that use a lot of energy, the cheetah runs swiftly and smoothly. "By applying knowledge about the movement patterns of the cheetah, you can develop robots that walk more elegantly and above all efficiently," Folkertsma continues. His research provides valuable knowledge that can be used to optimize the robots of the future, designed to support us in areas such as healthcare or housekeeping. The knowledge gained from the project can also be put to good use in rehabilitation robots or advanced prosthetics that are equipped with robotics. Folkertsma studied extensive video footage of cheetahs and used software to analyse their movements. The backbone proves crucial to the power this big cat generates. Bending and extending its spine enables the cheetah to move efficiently, run exceptionally fast and make huge leaps. "The main difference between existing walking robots and my cheetah robot is therefore the backbone," Folkertsma says. "The trick was to imitate it without complicating matters unnecessarily: instead of vertebrae and intervertebral discs, we worked with a cleverly placed spring which delivers approximately the same effect. Cheetahs are also able to store a lot of energy in their muscles for later use. This too is something we have imitated by fitting carefully selected springs in our robot's legs." "My robot can be seen as a simulated skeleton, complete with muscles and joints. Not every element is where you would find it in the animal, but the spine, shoulders and hips occupy the same position. A real cheetah not only runs, but also climbs trees for example. That is not something our robot needs to copy. After all, the aim was not to reconstruct a cheetah, but to reap the rewards of its efficient way of running. By way of illustration, the robot does not have a normal foot, but a light-weight mechanism with springs which turned out to be more efficient." The prototype developed by Folkertsma weighs in at 2.5 kg and is 30 cm long: twenty times lighter than a real cheetah and four times smaller. Taking into account the weight difference, the robot moves using only about fifteen percent more energy than a real cheetah. The robot can currently reach a speed of about one kilometre per hour. "That's quite a pace for such a small robot," Folkertsma observes. "More research is needed to enable it to run as fast as a real cheetah, relatively speaking. That would entail getting up to a speed of around twenty kilometres per hour. A Master's student is currently working on a newly developed robotic leg and the first tests, focusing on a single leg, are already promising. With four legs of this type, the robot will be able to run much faster; I think this will help us make genuine advances." Geert Folkertsma will defend his PhD thesis entitled Energy-based and biomimetic robotics in the Prof. G. Berkhoff hall, in the Waaier Building on the University of Twente campus at 16.45 on 21 April. He conducted his doctoral research at the Department of Robotics and Mechatronics (RAM), under the supervision of Prof. Stefano Stramigioli.   Story Source: Materials provided by University of Twente. Note: Content may be edited for style and length.

Shell growth observed thanks to 'ion sponge'

Dutch and American researchers are able to observe the formation of shells in real time on a nanometer scale thanks to a new electron microscopy technique. This enabled them for the first time to see how pieces of polymer act as 'ion sponges' -- thereby confirming a 30-year-old theory. The required ions are absorbed so that crystals are only formed at these specific locations. The researchers publish their result today in Nature Materials. Their finding not only throws a new light on biological crystal formation in nature, which is still not fully understood. The results also provide additional understanding of industrial crystal formation processes, which are used for example to increase efficiency in the production of ICs and solar cells. Natural biomineralization, through which organisms and minerals grow, typically in shells and teeth, follows a process that technologists can only dream of. Our control of the present industrial crystallization processes is relatively primitive, compared with the perfection with which crystals grow and are ordered in nature. Therefore, scientists have for decades been trying desperately to understand and control these unique chemical processes in nature. New theory At the end of the 1980s, researchers in Israel presented a new theory about the first steps in the formation of shells, in which calcium and carbonate ions are present in solution shortly before they bond and crystallize into the well known, hard material: calcium carbonate. They believe that this crystallization process is initiated by surfaces of insoluble biopolymers that act as 'ion sponge': they attract calcium ions, so that they concentrate in these specific locations. The carbonate ions can then bond much more easily to the calcium, in a way that the calcium carbonate crystals only form at the specific locations of the sponges. Liquid microscopy More than 30 years later, the technology is now advanced enough and researchers from Eindhoven University of Technology (TU/e), Pacific Northwest National Laboratory (PNNL) and Lawrence Berkeley National Laboratory led by Nico Sommerdijk (TU/e) and Jim de Yoreo (PNNL) have indeed seen how these ion sponges are formed. Using a new kind of electron microscopy technique, they have observed the formation of shells in a solution, in real time and on a nanometer scale. "This is a big difference from the earlier standard, in which you have to freeze samples. This means you could only study the individual steps in the process. Instead of studying 'snapshots' of those separate steps, we can now look at a 'film' of the complete process," says Sommerdijk. 'Aquarium' In the experiment, the polymer polystyrene sulfonate acts as an 'ion sponge'. The solution to be studied was covered by thin, transparent membranes, forming a kind of 'aquarium'. Using inlet valves, the researchers were able to allow ions of calcium and carbonate to flow into the experiment at will. In a first experiment without the polymer, few interesting effects were observed: the usual small crystals only formed occasionally. But with the addition of the polymer, it was clearly visible how the calcium was mainly adsorbed by the polymer, after which crystals formed primarily at these locations in the presence of the carbonate crystals. In addition the process was many times faster than without the polymer. Efficient crystal formation Crystallization is used in many technology applications, for example in nanotechnology or in the production of pharmaceuticals. "To get the crystallization process started just requires -- in simple terms -- the solution to be made less soluble," Sommerdijk explains. "For example if I allow a warm solution of sugar to cool, the sugar will crystallize. But you never know where exactly the crystals will grow. With this kind of sponge, you can not only control where the crystals will grow, but also how the process will take place. This means you have much better control not only of their location, but also of their shape." Story Source: Materials provided by Eindhoven University of Technology. Note: Content may be edited for style and length.

Nanoparticles remain unpredictable

The nanotech industry is booming. Every year, several thousands of tonnes of human-made nanoparticles are produced worldwide; sooner or later, a certain part of them will end up in bodies of water or soil. But even experts find it difficult to say exactly what happens to them there. It is a complex question, not only because there are many different types of human-made (engineered) nanoparticles, but also because the particles behave differently in the environment depending on the prevailing conditions. Researchers led by Martin Scheringer, Senior Scientist at the Department of Chemistry and Applied Biosciences, wanted to bring some clarity to this issue. They reviewed 270 scientific studies, and the nearly 1,000 laboratory experiments described in them, looking for patterns in the behaviour of engineered nanoparticles. The goal was to make universal predictions about the behaviour of the particles. Particles attach themselves to everything However, the researchers found a very mixed picture when they looked at the data. "The situation is more complex than many scientists would previously have predicted," says Scheringer. "We need to recognise that we can't draw a uniform picture with the data available to us today." Nicole Sani-Kast, a doctoral student in Scheringer's group and first author of the analysis published in the journal PNAS, adds: "Engineered nanoparticles behave very dynamically and are highly reactive. They attach themselves to everything they find: to other nanoparticles in order to form agglomerates, or to other molecules present in the environment." Network analysis To what exactly the particles react, and how quickly, depends on various factors such as the acidity of the water or soil, the concentration of the existing minerals and salts, and above all, the composition of the organic substances dissolved in the water or present in the soil. The fact that the engineered nanoparticles often have a surface coating makes things even more complicated. Depending on the environmental conditions, the particles retain or lose their coating, which in turn influences their reaction behaviour. To evaluate the results available in the literature, Sani-Kast used a network analysis for the first time in this research field. It is a technique familiar in social research for measuring networks of social relations, and allowed her to show that the data available on engineered nanoparticles is inconsistent, insufficiently diverse and poorly structured. More method for machine learning "If more structured, consistent and sufficiently diverse data were available, it may be possible to discover universal patterns using machine learning methods," says Scheringer, "but we're not there yet." Enough structured experimental data must first be available. "In order for the scientific community to carry out such experiments in a systematic and standardised manner, some kind of coordination is necessary," adds Sani-Kast, but she is aware that such work is difficult to coordinate. Scientists are generally well known for preferring to explore new methods and conditions rather than routinely performing standardized experiments. [Box:] Distinguishing human-made and natural nanoparticles In addition to the lack of systematic research, there is also a second tangible problem in researching the behaviour of engineered nanoparticles: many engineered nanoparticles consist of chemical compounds that occur naturally in the soil. So far it has been difficult to measure the engineered particles in the environment since it is hard to distinguish them from naturally occurring particles with the same chemical composition. However, researchers at ETH Zurich's Department of Chemistry and Applied Biosciences, under the direction of ETH Professor Detlef Günther, have recently established an effective method that makes such a distinction possible in routine investigations. They used a state-of-the-art and highly sensitive mass spectrometry technique (called spICP-TOF mass spectrometry) to determine which chemical elements make up individual nanoparticles in a sample. In collaboration with scientists from the University of Vienna, the ETH researchers applied the method to soil samples with natural cerium-containing particles, into which they mixed engineered cerium dioxide nanoparticles. Using machine learning methods, which were ideally suited to this particular issue, the researchers were able to identify differences in the chemical fingerprints of the two particle classes. "While artificially produced nanoparticles often consist of a single compound, natural nanoparticles usually still contain a number of additional chemical elements," explains Alexander Gundlach-Graham, a postdoc in Günther's group. The new measuring method is very sensitive: the scientists were able to measure engineered particles in samples with up to one hundred times more natural particles.   Story Source: Materials provided by ETH Zurich. Note: Content may be edited for style and length.

Diamond’s 2-billion-year growth charts tectonic shift in early Earth’s carbon cycle

 A study of tiny mineral 'inclusions' within diamonds from Botswana has shown that diamond crystals can take billions of years to grow. One diamond was found to contain silicate material that formed 2.3 billion years ago in its interior and a 250 million-year-old garnet crystal towards its outer rim, the largest age range ever detected in a single specimen. Analysis of the inclusions also suggests that the way that carbon is exchanged and deposited between the atmosphere, biosphere, oceans and geosphere may have changed significantly over the past 2.5 billion years. 'Although a jeweller would consider diamonds with lots of inclusions to be flawed, for a geologist these are the most valuable and exciting specimens,' said Prof Gareth Davies, of Vrije Universiteit (VU) Amsterdam, who co-authored the study. 'We can use the inclusions to date different parts of an individual diamond, and that allows us to potentially look at how the processes that formed diamonds may have changed over time and how this may be related to the changing carbon cycle on Earth.' Sixteen diamonds from two mines in north eastern Botswana were analysed in the study: seven specimens from the Orapa mine and nine from the Letlhakane mine. A team at VU Amsterdam measured the radioisotope, nitrogen and trace element contents of inclusions within the diamonds. Although the mines are located just 40 kilometres apart, the diamonds from the two sources had significant differences in the age range and chemical composition of inclusions. The Orapa diamonds contained material dating from between around 400 million and more than 1.4 billion years ago. The Letlhakane diamond inclusions ranged from less than 700 million and up to 2-2.5 billion years old. In every case, the team were able to link the age and composition of material in the inclusions to distinct tectonic events occurring locally in the Earth's crust, such as a collision between plates, continental rifting or magmatism. This suggests that diamond formation is triggered by heat fluctuations and magma fluid movement associated with these events. The Letlhakane diamonds also provided a rare opportunity to look back in time to the early Earth. The oldest inclusions date back to before the Great Oxidation Event (GOE) around 2.3 billion years ago, when oxygen produced by multicellular cyanobacteria started to fill the atmosphere, radically changing the weathering and sediment formation processes and thus altering the chemistry of rocks. 'The oldest inclusions in the diamonds contain a higher proportion of the lighter carbon isotope. As photosynthesis favours the lighter isotope, carbon 12, over the heavier carbon 13, this 'light' ratio finding suggests that organic material from biological sources may have been more abundant in diamond-forming zones early in the Earth's history than we find today,' explained Suzette Timmerman, lead author on the study. 'Higher temperatures in the Earth's interior before the GOE may have affected the way that carbon was released into the diamond forming regions beneath the Earth's continental plates and may be evidence of a fundamental change in tectonic processes. However, we are currently working with a very small dataset and need further studies to establish if this is a global phenomenon.' Story Source: Materials provided by Europlanet Media Centre. Note: Content may be edited for style and length.
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