INAE Monthly E-News Letter Vol. VIII, Issue 5, May 1, 2017

 (+) Academy Activities

From the Editor’s Desk

A Humane Organization

A humane organization has adaptability, diversity, and creativity. It responds to new concepts and new knowledge.  It wants to learn and is flexible. In a humane organization, an employee is first a human being, and the Read more...

Purnendu Ghosh
Chief Editor of Publications

 (+) Editorial Board, INAE

 (+) Articles by INAE Fellows

Dr Purnendu Ghosh
Dr Baldev Raj
Dr K V Raghavan
Dr Sanak Mishra
Prof. Indranil Manna
Prof BS Murty
Prof Sanghamitra Bandyopadhyay
Prof Pradip Dutta
Prof Manoj K Tiwari
Prof Sanjay Mittal
Prof Prasun K Roy
Brig Rajan Minocha

 (+) Engineering and Technology Updates

  Civil Engineering

  Computer Engineering  and Information Technology

  Mechanical Engineering

  Chemical Engineering

  Electrical Engineering

  Electronics and Communication Engineering

  Aerospace Engineering

  Mining, Metallurgical and Materials Engineering

  Energy Engineering

  Interdisciplinary Engineering and Special Fields 

 (+) Engineering Innovation in India
 (+) Previous E-newsletter

 

Civil Engineering

1. Performance of Earthquake Early Warning Systems

The future of earthquake early warning systems may be contained in smartphones — and vehicles, and “smart” appliances and the increasing number of everyday objects embedded with sensors and communication chips that connect them with a global network.At a presentation at the 2017 Seismological Society of America’s (SSA) Annual Meeting, Benjamin Brooks of the U.S. Geological Survey and colleagues will share data from a recent project in Chile that provided early detection, estimates and locations for earthquakes using a network of sensor boxes equipped with smartphones and consumer-quality GPS chips. Data collected by the sensor boxes is transmitted through an Android app developed by the researchers and analyzed to produce earthquake source models, which in turn can be used to create ground shaking forecasts and local tsunami warnings.The sensor stations have successfully detected three magnitude 5 or larger earthquakes since December 2016, with no false alarms. Although the smartphone-based sensors in the study are distributed in a fixed network, Brooks and colleagues say, it may be possible to someday harness individual smartphones and “smart” appliances into a crowd-sourced network for earthquake early warning.On the U.S West Coast, seismologists at the University of Washington are expanding and testing the capabilities of earthquake early warning systems already under development, such as the G-FAST system in the Pacific Northwest, and ShakeAlert in California. Brendan Crowell and colleagues will discuss the performance of G-FAST as tested by 1300 simulated megathrust earthquakes of magnitudes between 7.5 and 9.5 in the Cascadia region. Renate Hartog will present data suggesting that the algorithms behind ShakeAlert can be configured to work for the Pacific Northwest as well as California, suggesting that a West Coast-wide earthquake early warning system could be closer to reality.In other presentations at the SSA Annual Meeting, researchers will also discuss how earthquake early warning systems are developing ways to improve real-time ground motion alerts. Many early warning systems perform best when asked to pinpoint the magnitude and location of earthquakes, but ground motion warnings are also key to predicting and preventing infrastructure damage and destruction.

 

Source : https://www.sciencedaily.com/releases/2017/04/170411130741.htm

 

Computer Engineering and Information Technology

2.  Internet Atlas Maps the Physical Internet to Enhance Security

A team of scientists developed Internet Atlas, the first detailed map of the internet’s structure worldwide. The lines represent crucial pieces of the physical infrastructure of the internet that billions of people rely on.

Despite the internet-dependent nature of our world, a thorough understanding of the internet’s physical makeup has only recently emerged, thanks to painstaking work by University of Wisconsin-Madison researchers and their collaborators.Professor of Computer Sciences Paul Barford, Ph.D. candidate Ramakrishnan Durairajan and colleagues have developed Internet Atlas, the first detailed map of the internet’s structure worldwide.While average users rarely think of these elements, things like submarine cables — buried below the ocean floor — run between continents to enable communication. Data centers in buildings all over the world are packed with servers storing many types of data. Traffic exchange occurs between different service providers at internet exchange points.Though these and other elements may be out of sight for the average user, they are crucial pieces of the physical infrastructure that billions of people rely on.Internet Atlas was one of a select group of DHS-funded projects invited to present at the conference. Mapping the physical internet helps stakeholders boost performance and guard against a number of threats, from terrorism to extreme weather events like hurricanes. Furthermore, “a lot of infrastructure is by major right-of-ways, like railroad lines,” says Barford, meaning that an event like a train derailment could end up disrupting internet communications. “The question of ‘how does mapping contribute to security?’ is one of our fundamental concerns,” says Durairajan.The project has helped direct attention to the problem of shared risk, the subject of an influential 2015 paper by the team. Physical infrastructure is commonly shared by multiple networking entities, so damage to any particular piece of infrastructure can impact more than one entity. “We quantified that for the first time,” says Barford.Much of the data used to create the Internet Atlas comes from publicly available information, such as what internet service providers publish on their websites. Other data has taken more legwork to uncover, such as combing through mundane items like local permits for laying cables. “The core work is grunt work, but by rolling up our sleeves, we assembled a unique data set,” says Barford.Now, the team is looking to enhance the maps even further and share their work so it can be deployed by others to boost network performance and security.”We’ll complement the static maps with the ability to actually examine the status of the network in real time,” says Barford. “We’ve built certain capabilities that allow exactly that to be done, and one of the important focuses going forward is to enhance that capability, basically putting the maps in motion.”



Source : https://www.sciencedaily.com/releases/2017/04/170411141033.htm
 

 

Mechanical Engineering

3.  Device Pulls Water from Dry Air, Powered Only by The Sun

This is the water harvester built at MIT with MOFs from UC Berkeley. Using only sunlight, the harvester can pull liters of water from low-humidity air over a 12-hour period.

Imagine a future in which every home has an appliance that pulls all the water the household needs out of the air, even in dry or desert climates, using only the power of the sun.That future may be around the corner, with the demonstration this week of a water harvester that uses only ambient sunlight to pull liters of water out of the air each day in conditions as low as 20 percent humidity, a level common in arid areas.The solar-powered harvesterwas constructed at the Massachusetts Institute of Technology using a special material — a metal-organic framework, or MOF — produced at the University of California, Berkeley.”This is a major breakthrough in the long-standing challenge of harvesting water from the air at low humidity,” said Omar Yaghi, one of two senior authors of the paper, who is a faculty scientist at Lawrence Berkeley National Laboratory. “There is no other way to do that right now, except by using extra energy. Your electric dehumidifier at home ‘produces’ very expensive water.”The prototype, under conditions of 20-30 percent humidity, was able to pull 2.8 liters of water from the air over a 12-hour period, using one kilogram of MOF. Rooftop tests at MIT confirmed that the device works in real-world conditions.”One vision for the future is to have water off-grid, where you have a device at home running on ambient solar for delivering water that satisfies the needs of a household,” said Yaghi, who is the founding director of the Berkeley Global Science Institute. Yaghi invented metal-organic frameworks more than 20 years ago, combining metals like magnesium or aluminum with organic molecules in a tinker-toy arrangement to create rigid, porous structures ideal for storing gases and liquids. Since then, more than 20,000 different MOFs have been created by researchers worldwide. Some hold chemicals such as hydrogen or methane: the chemical company BASF is testing one of Yaghi’s MOFs in natural gas-fueled trucks, since MOF-filled tanks hold three times the methane that can be pumped under pressure into an empty tank.Other MOFs are able to capture carbon dioxide from flue gases, catalyze the reaction of adsorbed chemicals or separate petrochemicals in processing plants.In 2014, Yaghi and his UC Berkeley team synthesized a MOF — a combination of zirconium metal and adipic acid — that binds water vapor, and he suggested to Evelyn Wang, a mechanical engineer at MIT, that they join forces to turn the MOF into a water-collecting system.The system Wang and her students designed consisted of more than two pounds of dust-sized MOF crystals compressed between a solar absorber and a condenser plate, placed inside a chamber open to the air. As ambient air diffuses through the porous MOF, water molecules preferentially attach to the interior surfaces. X-ray diffraction studies have shown that the water vapor molecules often gather in groups of eight to form cubes.Sunlight entering through a window heats up the MOF and drives the bound water toward the condenser, which is at the temperature of the outside air. The vapor condenses as liquid water and drips into a collector.”This work offers a new way to harvest water from air that does not require high relative humidity conditions and is much more energy efficient than other existing technologies,” Wang said.This proof of concept harvester leaves much room for improvement, Yaghi said. The current MOF can absorb only 20 percent of its weight in water, but other MOF materials could possibly absorb 40 percent or more. The material can also be tweaked to be more effective at higher or lower humidity levels.”It’s not just that we made a passive device that sits there collecting water; we have now laid both the experimental and theoretical foundations so that we can screen other MOFs, thousands of which could be made, to find even better materials,” he said. “There is a lot of potential for scaling up the amount of water that is being harvested. It is just a matter of further engineering now.”Yaghi and his team are at work improving their MOFs, while Wang continues to improve the harvesting system to produce more water.”To have water running all the time, you could design a system that absorbs the humidity during the night and evolves it during the day,” he said. “Or design the solar collector to allow for this at a much faster rate, where more air is pushed in. We wanted to demonstrate that if you are cut off somewhere in the desert, you could survive because of this device. A person needs about a Coke can of water per day. That is something one could collect in less than an hour with this system.”



Source: https://www.sciencedaily.com/releases/2017/04/170413141104.htm
 

 

Chemical Engineering

4.  Chemists Devise Simple Method for Making Sought-After Boronic Acid-Based Drugs and Other Products

Chemists at The Scripps Research Institute (TSRI) have developed a broad and strikingly easy method for synthesizing a class of molecules that have demonstrated value as pharmaceuticals.The difficulty of preparing these compounds — boronic acids and closely related molecules known as boronate esters — has greatly limited their use in the pharmaceutical industry, and to date there are only three FDA-approved drugs in this category.

With the new method chemists can take abundant, inexpensive, structurally diverse compounds known as carboxylic acids and convert them easily into similarly structured boronic acids and related compounds. “Carboxylic acids are the ideal starting material for synthesizing boronic acids, but until now there hasn’t been any method for getting from one to the other,” said principal investigator Phil S. Baran, Darlene Shiley Professor of Chemistry at TSRI.Among the boronic acid-derived molecules Baran and his team made in demonstrating the new method were several novel compounds that are now being investigated further as potential treatments for COPD and other lung disorders.The development of the new method, known as decarboxylative borylation, follows a breakthrough made a year ago when Baran and his team were studying a reaction commonly used in laboratory chemistry as well as in nature: the amide-bond forming reaction, which among other things, helps stitch amino acids into proteins. “We realized that the principles of amide bond formation, still the most utilized reaction in all of chemical synthesis, could be used to simplify a much broader set of molecule-building tasks,” Baran said.In this case, the insight enables the transformation of virtually any carboxylic acid, whether simple or complex, using just a single reaction step and inexpensive nickel catalysts. The new method essentially replaces a key carbon atom on a carboxylic acid with a boron atom. “Instead of devoting 95 percent of their effort to introducing a single boron atom, chemists can now easily install boron at any stage,” Baran said.Borylated versions of drug compounds should often have superior properties to their carboxylic acid counterparts. The new method for the first time makes it broadly practical for pharmaceutical chemists to create and investigate these borylated structures. To demonstrate, Baran and his team used the new method to make boronic acid versions of several common drugs, including Lipitor (atorvastatin) and vancomycin.In a collaboration to demonstrate the translational utility of the discovery, Baran’s team and chemists from the California Institute for Biomedical Research (Calibr), also used the method to make boronic acid-based compounds that inhibit a human enzyme known as neutrophil elastase. Immune cells release this enzyme within the lungs during infections and other conditions involving lung inflammation. Elastase is considered a major cause of the lung damage seen in COPD, cystic fibrosis, and related respiratory ailments.To date, elastase inhibitors developed through other methods have shown limited effectiveness and/or significant side effects, and so far none has been FDA-approved. However, the team found in initial lab-dish tests that their boronic acid-based compounds inhibit elastase more strongly than older elastase-inhibiting compounds. “We found that we could get a significant boost in potency by using a boronic acid group,” said study co-author Arnab Chatterjee, director of medicinal chemistry at Calibr.These boronic acid-based compounds can bind very tightly to their target molecules but in a way that allows them to detach eventually, thus potentially reducing the impact of off-target interactions that cause unwanted side effects.”The next step is to see how well these compounds perform in animal models,” said Chatterjee. “In general, this new method allows us in a practical way to get into this largely unexplored but promising chemical space of borylated compounds, and thus enables us to revisit old targets, such as elastase, that have largely resisted prior drug development efforts.”



Source: https://www.sciencedaily.com/releases/2017/04/170414123731.htm
 

 

Electrical Engineering

5. Tunable Electric Eyeglasses Bend to The Will of The Wearer

Engineers funded by the National Institute of Biomedical Imaging and Bioengineering (NIBIB) have developed glasses with liquid-based lenses that “flex” to refocus on whatever the wearer is viewing.The adjustable “smart glasses” were developed by a University of Utah team led by electrical and computer engineering professor Carlos H. Mastrangelo, Ph.D., and his doctoral student Nazmul Hasan. “The glasses incorporate an impressive array of electrical, mechanical, optical, sensor, and computer technologies with the goal of developing a one-size-fits-all approach to vision correction,” said Andrew Weitz, Ph.D., NIBIB program director, whose expertise includes bioelectronic vision technologies.The glasses are designed to mimic the behaviour of the eye’s natural lens — flexing to focus on wherever an individual is looking: near, far or in-between. Unfortunately for many of us, as we age our lenses become stiffer and lose the ability to bend enough to focus at different distances.Standard glasses compensate for the bend our ageing eyes can no longer achieve to focus. This becomes more complicated if we are unable to focus at multiple distances, which necessitates glasses with multiple lenses for different distances, such as bifocals, trifocals or progressive lenses, which must be regularly replaced as our eyesight changes.The central technology of the glasses created by the research team are lenses made of glycerin, a clear thick liquid sandwiched between flexible membranes. The lenses are mounted into frames that have an electromechanical system that causes the membranes to bend to adjust their focus. The ability of the lens to flex and bend allows the single lens to act like multiple lenses.The glasses are designed to work for most people at a wide range of distances due to a sophisticated computer algorithm that works with two critical variables. One is the eyeglass prescription that the user enters into the system using an attached mobile app. The other is where the user is looking — specifically how far away. This information is provided by a sensor mounted in the bridge of the glasses that uses pulses of infrared light to identify where the user is looking and provide the precise distance.The combination of the user’s prescription information and the distance information is used by the algorithm to instantly adjust the shape of the liquid lenses to allow the user to focus on what they are viewing. Remarkably, if the user looks elsewhere, the change in lens shape needed to focus at the new distance is made in a staggering 14 milliseconds — 25 times faster than an eye blink.”Theoretically, these would be the only glasses a person would ever have to buy because they can correct the majority of focusing problems,” says Mastrangelo. “Users just have to input their new prescription as their eyesight changes.”Because they house a lot of technology, including a rechargeable battery, the current prototype is on the bulky side. However, the research team is constantly improving the design to make them smaller and lighter. A startup company, Sharpeyes, has been created to move toward commercialization with the aim of making the glasses available on the market in about three years.



Source : https://www.sciencedaily.com/releases/2017/04/170411182509.htm
 

 

Electronics and Communication Engineering

6. Method Improves Semiconductor Fiber Optics, Paves Way for Developing Devices

Amorphous silicon core is inside a 1.7-micron inner-diameter glass capillary.

A new method to improve semiconductor fiber optics may lead to a material structure that might one day revolutionize the global transmission of data, according to an interdisciplinary team of researchers.Researchers are working with semiconductor optical fibers, which hold significant advantages over silica-based fiber optics, the current technology used for transmitting nearly all digital data. Silica — glass — fibers can only transmit electronic data converted to light data. This requires external electronic devices that are expensive and consume enormous amounts of electricity. Semiconductor fibers, however, can transmit both light and electronic data and might also be able to complete the conversion from electrical to optical data on the fly during transmission, improving delivery speed.Think of these conversions as exit ramps on the information superhighway, said Venkatraman Gopalan, professor of materials science and engineering, Penn State. The fewer the exits the data takes, the faster the information travels. Call it “fly-by optoelectronics,” he said.In 2006, researchers, first developed silicon fibers by embedding silicon and other semiconductor materials into silica-fiber capillaries. The fibers, comprised of a series of crystals, were limited in their ability to transmit data because imperfections, such as grain boundaries at the surfaces where the many crystals within the fiber core bonded together, forced portions of the light to scatter, disrupting the transmission.A method improves on the polycrystalline core of the fiber by melting a high-purity amorphous silicon core deposited inside a 1.7-micron inner-diameter glass capillary using a scanning laser, allowing for formation of silicon single crystals that were more than 2,000 times as long as they were thick. This method transforms the core from a polycrystal with many imperfections to a single crystal with few imperfections that transmits light much more efficiently.That process demonstrates a new methodology to improve data transfer by eliminating imperfections in the fiber core that can be made of various materials. Because of the ultra-small core, the researcher was able to melt and refine the crystal structure of the core material at temperatures of about 750 to 930 degrees Fahrenheit, lower than a typical fiber-drawing process for silicon core fibers. The lower temperatures and the short heating time that can be controlled by the laser power and the laser scanning speed also prevented the silica capillary, which has different thermal properties, from softening and contaminating the core.”High purity is fundamentally important for high performance when dealing with materials designated for optical or electrical use,” said a researcher.The important takeaway, said a scioentist, is that this new method lays out the methodology for how a host of materials can be embedded into fiber optics and how voids and imperfections can be reduced to increase light-transfer efficiency, necessary steps to advancing the science from its infancy.”Glass technology has taken us this far,” he said. “A researcher has been able to start from nicely deposited amorphous silicon and germanium core and use a laser to crystallize them, so that the whole semiconductor fiber core is one nice single crystal with no boundaries,” said Gopalan. “This improved light and electronic transfer. Now we can make some real devices, not just for communications, but also for endoscopy, imaging, fiber lasers and many more.”Gopalan said he is not only in the business of creating commercially viable materials. He is interested in dreaming big and taking the long view on new technologies. Perhaps one day, every new home constructed might have a semiconductor fiber, bringing faster internet to it.



Source: https://www.sciencedaily.com/releases/2017/04/170413101840.htm
 

 

Aerospace Engineering

7. Hubble Takes Close-Up Portrait of Jupiter

On April 3, 2017, as Jupiter made its nearest approach to Earth in a year, NASA’s Hubble Space Telescope viewed the solar system’s largest planet in all of its up-close glory. At a distance of 668 million kilometers from Earth, Jupiter offered spectacular views of its colourful, roiling atmosphere, the legendary Great Red Spot, and it smaller companion at farther southern latitudes dubbed “Red Spot Jr.”The giant planet is now at “opposition,” positioned directly opposite the sun from the Earth. This means that the sun, Earth and Jupiter line up, with Earth sitting between the sun and the gas giant. Opposition also marks Jupiter’s closest point to us, and the planet appears brighter in the night sky than at any other time in the year.This positioning allowed a team led by Amy Simon of NASA’s Goddard Space Flight Center in Greenbelt, Maryland to observe Jupiter using Hubble’s Wide Field Camera 3. Hubble photographed exquisite details in Jupiter’s atmosphere, as small as about 129 kilometers across.With its immense and powerful storms and hundreds of smaller vortices, the atmosphere of Jupiter is divided into several distinct, colourful bands, parallel to the equator. These bands, with alternating wind motions, are created by differences in the thickness and height of the ammonia ice clouds; the lighter bands rise higher and have thicker clouds than the darker bands. The bands are separated by winds that can reach speeds of up to 644 kilometers per hour.Jupiter is best known for the Great Red Spot, an anticyclone that has raged for at least 150 years. This famous storm is larger than Earth. However, the Great Red Spot is slowly shrinking — a trend seen since the late 1800s. The reason for this phenomenon is still unknown. Hubble will continue to observe Jupiter in hopes of solving this mysterious riddle.The images are part of the Outer Planets Atmospheres Legacy program or OPAL. This program provides yearly Hubble global views of the outer planets to look for changes in their storms, winds, and clouds. It began in 2014 with Uranus, and has been studying Jupiter and Neptune since 2015. In 2018, it will begin viewing Saturn.The team timed the Hubble observation to coincide with when NASA’s space probe Juno would be near its closest point to Jupiter, so that scientists could get concurrent observations.The Hubble Space Telescope is a project of international cooperation between NASA and ESA (European Space Agency). NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, Inc., in Washington, D.C.



Source : https://www.sciencedaily.com/releases/2017/04/170406143852.htm
 

 

Mining, Metallurgical and Materials Engineering

 

8.  Computers Create Recipe for Two New Magnetic Materials

This is a microscopic look at the atomic structure of a manganese-platinum-palladium mixture (Mn2PtPd), that is one of the newly predicted and manufactured magnetic materials. Each color shows the distribution of a different element. The uniformity for each material — with the exception the small spots indicating a different phase state — matches the predictions for a stable three-element material.

Material scientists have predicted and built two new magnetic materials, atom-by-atom, using high-throughput computational models. The success marks a new era for the large-scale design of new magnetic materials at unprecedented speed.Although magnets abound in everyday life, they are actually rarities — only about five percent of known inorganic compounds show even a hint of magnetism. And of those, just a few dozen are useful in real-world applications because of variability in properties such as effective temperature range and magnetic permanence.The relative scarcity of these materials can make them expensive or difficult to obtain, leading many to search for new options given how important magnets are in applications ranging from motors to magnetic resonance imaging (MRI) machines. The traditional process involves little more than trial and error, as researchers produce different molecular structures in hopes of finding one with magnetic properties. Many high-performance magnets, however, are singular oddities among physical and chemical trends that defy intuition.In a new study, materials scientists from Duke University provide a shortcut in this process. They show the capability to predict magnetism in new materials through computer models that can screen hundreds of thousands of candidates in short order. And, to prove it works, they’ve created two magnetic materials that have never been seen before.The group focused on a family of materials called Heusler alloys — materials made with atoms from three different elements arranged in one of three distinct structures. Considering all the possible combinations and arrangements available using 55 elements, the researchers had 236,115 potential prototypes to choose from.To narrow the list down, the researchers built each prototype atom-by-atom in a computational model. By calculating how the atoms would likely interact and the energy each structure would require, the list dwindled to 35,602 potentially stable compounds.From there, the researchers conducted a more stringent test of stability. Generally speaking, materials stabilize into the arrangement requiring the least amount of energy to maintain. By checking each compound against other atomic arrangements and throwing out those that would be beat out by their competition, the list shrank to 248.Of those 248, only 22 materials showed a calculated magnetic moment. The final cut dropped any materials with competing alternative structures too close for comfort, leaving a final 14 candidates to bring from theoretical model into the real world.But as most things in a laboratory turn out, synthesizing new materials is easier said than done. After years of attempting to create four of the materials, researchers succeeded with two.Both were, as predicted, magnetic.The first newly minted magnetic material was made of cobalt, magnesium and titanium (Co2MnTi). By comparing the measured properties of similarly structured magnets, the researchers were able to predict the new magnet’s properties with a high degree of accuracy. Of particular note, they predicted the temperature at which the new material lost its magnetism to be 940 K. In testing, the actual “Curie temperature” turned out to be 938 K — an exceptionally high number. This, along with its lack of rare earth elements, makes it potentially useful in many commercial applications.”Many high-performance permanent magnets contain rare earth elements,” said a researcher. “And rare earth materials can be expensive and difficult to acquire, particularly those that can only be found in Africa and China. The search for magnets free of rare-earth materials is critical, especially as the world seems to be shying away from globalization.”The second material was a mixture of manganese, platinum and palladium (Mn2PtPd), which turned out to be an antiferromagnet, meaning that its electrons are evenly divided in their alignments. This leads the material to have no internal magnetic moment of its own, but makes its electrons responsive to external magnetic fields.While this property doesn’t have many applications outside of magnetic field sensing, hard drives and Random Access Memory (RAM), these types of magnets are extremely difficult to predict. Nevertheless, the group’s calculations for its various properties remained spot on.”It doesn’t really matter if either of these new magnets proves useful in the future,” said a lead researcher. “The ability to rapidly predict their existence is a major coup and will be invaluable to materials scientists moving forward.”



Source : https://www.sciencedaily.com/releases/2017/04/170415095611.htm
 

 

Energy Engineering 

9. New Infrared-Emitting Device Could Allow Energy Harvesting from Waste Heat

This illustration shows the room temperature MEMS metamaterial, which can achieve reconfigurable infrared intensities equivalent to a temperature change of nearly 20 degrees Celsius.

A new reconfigurable device that emits patterns of thermal infrared light in a fully controllable manner could one day make it possible to collect waste heat at infrared wavelengths and turn it into usable energy.The new technology could be used to improve thermophotovoltaics, a type of solar cell that uses infrared light, or heat, rather than the visible light absorbed by traditional solar cells. Scientists have been working to create thermophotovoltaics that are practical enough to harvest the heat energy found in hot areas, such as around furnaces and kilns used by the glass industry. They could also be used to turn heat coming from vehicle engines into energy to charge a car battery, for example.”Because the infrared energy emission, or intensity, is controllable, this new infrared emitter could provide a tailored way to collect and use energy from heat,” said Willie J. Padilla of Duke University, North Carolina. “There is a great deal of interest in utilizing waste heat, and our technology could improve this process.”The new device is based on metamaterials, synthetic materials that exhibit exotic properties not available from natural materials. Padilla and doctoral student Xinyu Liu used a metamaterial engineered to absorb and emit infrared wavelengths with very high efficiency. By combining it with the electronically controlled movement available from microelectromechanical systems (MEMS), the researchers created the first metamaterial device with infrared emission properties that can be quickly changed on a pixel-by-pixel basis. The new infrared-emitting device consists of an 8 × 8 array of individually controllable pixels, each measuring 120 X 120 microns. They demonstrated the MEMS metamaterial device by creating a “D” that is visible with an infrared camera.The researchers report that their infrared emitter can achieve a range of infrared intensities and can display patterns at speeds of up to 110 kHz, or more than 100,000 times per second. Scaling up the technology could allow it to be used to create dynamic infrared patterns for friend or foe identification during combat.In contrast to methods typically used to achieve variable infrared emission, the new technology emits tunable infrared energies without any change in temperature. Since the material is neither heated nor cooled, the device can be used at room temperature while other methods require high operating temperatures. Although experiments with natural materials have been successful at room-temperature, they are limited to narrow infrared spectral ranges.”In addition to allowing room-temperature operation, using metamaterials makes it simple to scale throughout the infrared wavelength range and into the visible or lower frequencies,” said Padilla. “This is because the device’s properties are achieved by the geometry, not by the chemical nature of the constituent materials that we’re using.”The new reconfigurable infrared emitter consists of a movable top layer of patterned metallic metamaterial and a bottom metallic layer that remains stationary. The device absorbs infrared photons and emits them with high efficiency when the two layers are touching but emits less infrared energy when the two layers are apart. An applied voltage controls the movement of the top layer, and the amount of infrared energy emitted depends on the exact voltage applied.

Using an infrared camera, the researchers demonstrated that they could dynamically modify the number of infrared photons coming off the surface of the MEMS metamaterial over a range of intensities equivalent to a temperature change of nearly 20 degrees Celsius.The researchers say that they could modify the metamaterial patterns used in the top layer to create different colored infrared pixels that would be each be tunable in intensity. This could allow the creation of infrared pixels that are similar to the RGB pixels used in a TV. They are now working to scale up the technology by making a device with more pixels — as many as 128 X 128 — and increasing the size of the pixels.”In principle, an approach similar to ours could be used to create many kinds of dynamic effects from reconfigurable metamaterials,” said Padilla. “This could be used to achieve a dynamic infrared optical cloak or a negative refractive index in the infrared, for example.”



Source : https://www.sciencedaily.com/releases/2017/04/170413101843.htm
 

 

Interdisciplinary Engineering and Special Fields

10. Nanoparticle Research Tested in Locusts Focuses on New Drug-Delivery Method

Delivering life-saving drugs directly to the brain in a safe and effective way is a challenge for medical providers. One key reason: the blood-brain barrier, which protects the brain from tissue-specific drug delivery. Methods such as an injection or a pill aren’t as precise or immediate as doctors might prefer, and ensuring delivery right to the brain often requires invasive, risky techniques.A team of engineers from Washington University in St. Louis has developed a new nanoparticle generation-delivery method that could someday vastly improve drug delivery to the brain, making it as simple as a sniff.”This would be a nanoparticle nasal spray, and the delivery system could allow a therapeutic dose of medicine to reach the brain within 30 minutes to one hour,” said Ramesh Raliya, research scientist at the School of Engineering & Applied Science.”The blood-brain barrier protects the brain from foreign substances in the blood that may injure the brain,” Raliya said. “But when we need to deliver something there, getting through that barrier is difficult and invasive. Our non-invasive technique can deliver drugs via nanoparticles, so there’s less risk and better response times.”The novel approach is based on aerosol science and engineering principles that allow the generation of monodisperse nanoparticles, which can deposit on upper regions of the nasal cavity via diffusion. Working with Assistant Vice Chancellor Pratim Biswas, chair of the Department of Energy, Environmental & Chemical Engineering and the Lucy & Stanley Lopata Professor, Raliya developed an aerosol consisting of gold nanoparticles of controlled size, shape and surface charge. The nanoparticles were tagged with fluorescent markers, allowing the researchers to track their movement.Next, Raliya and biomedical engineering postdoctoral fellow Debajit Saha exposed locusts’ antennae to the aerosol, and observed the nanoparticles travel from the antennas up through the olfactory nerves. Due to their tiny size, the nanoparticles passed through the brain-blood barrier, reaching the brain and suffusing it in a matter of minutes.The team tested the concept in locusts because the blood-brain barriers in the insects and humans have anatomical similarities, and the researchers consider going through the nasal regions to neural pathways as the optimal way to access the brain.

“The shortest and possibly the easiest path to the brain is through your nose,” said Barani Raman, associate professor of biomedical engineering. “Your nose, the olfactory bulb and then olfactory cortex: two relays and you’ve reached the cortex. The same is true for invertebrate olfactory circuitry, although the latter is a relatively simpler system, with supraesophageal ganglion instead of an olfactory bulb and cortex.”To determine whether or not the foreign nanoparticles disrupted normal brain function, Saha examined the physiological response of olfactory neurons in the locusts before and after the nanoparticle delivery. Several hours after the nanoparticle uptake, no noticeable change in the electrophysiological responses was detected.”This is only a beginning of a cool set of studies that can be performed to make nanoparticle-based drug delivery approaches more principled,” Raman said.The next phase of research involves fusing the gold nanoparticles with various medicines, and using ultrasound to target a more precise dose to specific areas of the brain, which would be especially beneficial in brain-tumour cases.”We want to drug target delivery within the brain using this non-invasive approach,” Raliya said. “In the case of a brain tumour, we hope to use focused ultrasound so we can guide the particles to collect at that particular point.”



Source : https://www.sciencedaily.com/releases/2017/04/170412145225.htm

 
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