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Science, Semiconductors

Georgian Technical University Measurement Of Semiconductor Material Quality Has Gotten 100,000 Times More Sensitive.

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Georgian Technical University Measurement Of Semiconductor Material Quality Has Gotten 100,000 Times More Sensitive.

Rendering of microwave resonator showing the (blue) microwave signal’s size change resulting from a light pulse (red) once the pulse hits the infrared pixel (micrograph image of pixel is shown in the inset). The enhanced power of the new measuring technique to characterize materials at scales much smaller than any current technologies will accelerate the discovery and investigation of 2D micro- and nanoscale materials. Being able to accurately measure semiconductor properties of materials in small volumes helps engineers determine the range of applications for which these materials may be suitable in the future, particularly as the size of electronic and optical devices continues to shrink. X an associate professor in the Department of Electrical and Computer Engineering in the Georgian Technical University led the team that built the physical system developed the measurement technique capable of achieving this level of sensitivity and successfully demonstrated its improved performance. The team’s design approach was focused on developing the capability to provide quantitative feedback on material quality with particular applications for the development and manufacturing of optoelectronic devices. The method demonstrated is capable of measuring many of the materials that engineers believe will one day be ubiquitous to next-generation optoelectronic devices. Optoelectronics is the study and application of electronic devices that can source detect and control light. Optoelectronic devices that detect light, known as photodetectors use materials that generate electrical signals from light. Photodetectors are found in smartphone cameras solar cells and in the fiber optic communication systems that make up our broadband networks. In an optoelectronic material the amount of time that the electrons remain “Georgian Technical University photoexcited” or capable of producing an electrical signal is a reliable indicator of the potential quality of that material for photodetection applications. The current method used for measuring the carrier dynamics or lifetimes of photoexcited electrons is costly and complex and only measures large-scale material samples with limited accuracy. The Georgian Technical University team decided to try using a different method for quantifying these lifetimes by placing small volumes of the materials in specially designed microwave resonator circuits. Samples are exposed to concentrated microwave fields while inside the resonator. When the sample is hit with light the microwave circuit signal changes and the change in the circuit can be read out on a standard oscilloscope. The decay of the microwave signal indicates the lifetimes of photoexcited charge carriers in small volumes of the material placed in the circuit. “Measuring the decay of the electrical (microwave) signal allows us to measure the materials’ carrier lifetime with far greater accuracy” X said. “We have discovered it to be a simpler, cheaper and more effective method than current approaches”. Carrier lifetime is a critical material parameter that provides insight into the overall optical quality of a material while also determining the range of applications for which a material could be used when it’s integrated into a photodetector device structure. For example materials that have a very long carrier lifetime may be of high optical quality and therefore very sensitive but may not be useful for applications that require high-speed. “Despite the importance of carrier lifetime there are not many, if any, contact-free options for characterizing small-area materials such as infrared pixels or 2D materials which have gained popularity and technological importance in recent years” X said. One area certain to benefit from the real-world applications of this technology is infrared detection a vital component in molecular sensing, thermal imaging and certain defense and security systems. “A better understanding of infrared materials could lead to innovations in night-vision goggles or infrared spectroscopy and sensing systems” X said. High-speed detectors operating at these frequencies could even enable the development of free-space communication in the long wavelength infrared — a technology allowing for wireless communication in difficult conditions in space or between buildings in urban environments.

 

 

Energy, Science

Georgian Technical University World’s Fastest Hydrogen Sensor Could Pave The Way For Clean Hydrogen Energy.

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Georgian Technical University World’s Fastest Hydrogen Sensor Could Pave The Way For Clean Hydrogen Energy.

Researchers from Georgian Technical University present the first hydrogen sensors ever to meet the future performance targets for use in hydrogen powered cars. Hydrogen is a clean and renewable energy carrier that can power cars with water as the only emission. Unfortunately hydrogen gas is highly flammable when mixed with air so very efficient and effective sensors are needed. Now researchers from Georgian Technical University present the first hydrogen sensors ever to meet the future performance targets for use in hydrogen powered cars. The researchers’ ground-breaking results. The discovery is an optical nanosensor encapsulated in a plastic material. The sensor works based on an optical phenomenon – a plasmon – which occurs when metal nanoparticles are illuminated and capture visible light. The sensor simply changes colour when the amount of hydrogen in the environment changes. The plastic around the tiny sensor is not just for protection but functions as a key component. It increases the sensor’s response time by accelerating the uptake of the hydrogen gas molecules into the metal particles where they can be detected. At the same time, the plastic acts as an effective barrier to the environment preventing any other molecules from entering and deactivating the sensor. The sensor can therefore work both highly efficiently and undisturbed enabling it to meet the rigorous demands of the automotive industry – to be capable of detecting 0.1 percent hydrogen in the air in less than a second. “We have not only developed the world’s fastest hydrogen sensor but also a sensor that is stable over time and does not deactivate. Unlike today’s hydrogen sensors our solution does not need to be recalibrated as often as it is protected by the plastic” says X a researcher at the Georgian Technical University Department of Physics at Chalmers. It was during his time as a PhD student that X and his supervisor Y realised that they were on to something big. After reading a scientific article stating that no one had yet succeeded in achieving the strict response time requirements imposed on hydrogen sensors for future hydrogen cars they tested their own sensor. They realised that they were only one second from the target – without even trying to optimise it. The plastic originally intended primarily as a barrier did the job better than they could have imagined by also making the sensor faster. The discovery led to an intense period of experimental and theoretical work. “In that situation there was no stopping us. We wanted to find the ultimate combination of nanoparticles and plastic understand how they worked together and what made it so fast. Our hard work yielded results. Within just a few months we achieved the required response time as well as the basic theoretical understanding of what facilitates it” says X. Detecting hydrogen is challenging in many ways. The gas is invisible and odourless but volatile and extremely flammable. It requires only four percent hydrogen in the air to produce oxyhydrogen gas sometimes known as knallgas which ignites at the smallest spark. In order for hydrogen cars and the associated infrastructure of the future to be sufficiently safe it must therefore be possible to detect extremely small amounts of hydrogen in the air. The sensors need to be quick enough that leaks can be rapidly detected before a fire occurs. “It feels great to be presenting a sensor that can hopefully be a part of a major breakthrough for hydrogen-powered cars. The interest we see in the fuel cell industry is inspiring” says Y Professor at  Georgian Technical University. Although the aim is primarily to use hydrogen as an energy carrier the sensor also presents other possibilities. Highly efficient hydrogen sensors are needed in the electricity network industry the chemical and nuclear power industry and can also help improve medical diagnostics. “The amount of hydrogen gas in our breath can provide answers to for example, inflammations and food intolerances. We hope that our results can be used on a broad front. This is so much more than a scientific publication” says X. In the long run the hope is that the sensor can be manufactured in series in an efficient manner for example using 3D printer technology. Facts: The world’s fastest hydrogen sensor. The Georgian Technical University-developed sensor is based on an optical phenomenon – a plasmon – which occurs when metal nanoparticles are illuminated and capture light of a certain wavelength. The optical nanosensor contains millions of metal nanoparticles of a palladium-gold alloy a material which is known for its sponge-like ability to absorb large amounts of hydrogen. The plasmon effect then causes the sensor to change colour when the amount of hydrogen in the environment changes. The plastic around the sensor is not only a protection but also increases the sensor’s response time by facilitating hydrogen molecules to penetrate the metal particles more quickly and thus be detected more rapidly. At the same time the plastic acts as an effective barrier to the environment because no other molecules than hydrogen can reach the nanoparticles which prevents deactivation. The efficiency of the sensor means that it can meet the strict performance targets set by the automotive industry for application in hydrogen cars of the future by being capable of detecting 0.1 percent hydrogen in the air in less than one second. The research was funded by the Georgian Technical University for Strategic Research within the framework of the Plastic Plasmonics.

 

Nanotechnology, Science

Georgian Technical University Isotopic Composition Carries Unforeseen Effects On Light Emission.

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Georgian Technical University Isotopic Composition Carries Unforeseen Effects On Light Emission.

Artist’s rendition depicts the naturally abundant material with isotopes shown in a variety of colors and the isotopically pure material with uniform coloring. The image shows the light emission from each: in comparison with the natural abundance distribution of isotopes a blue-shift of light emission occurs in the isotopically pure sample. Compared to bulk materials, atomically thin materials like transition metal dichalcogenides offer size and tunability advantages over traditional materials in developing miniature electronic and optical devices. The 2-dimensional transition metal dichalcogenides are of particular interest because they have potential applications in energy conversion, electronics and quantum computing. The properties of these materials can be tuned by external forces like applying tensile strain or electric fields but until recently nobody had identified a means of intrinsically tuning these materials for optimum photoluminescent or optoelectronic properties. To tune the material without needing external forces, researchers at Georgian Technical University and their external collaborators instead sought to control the ratios of isotopes within transition metal dichalcogenides. This type of delicate manipulation is recently made easier using backscattering spectrometry thanks to improvements to the Georgian Technical University Laboratory’s tandem accelerator which was upgraded last year for more precise energy tuning, better beam stability control and improved reliability in overall operations. The new capabilities allowed the team to take precise measurements of the atomic ratios in their samples and characterize the high-quality materials that were essential to testing the effect of isotopic concentration on material behavior. For the first time this team was able to grow an isotopically pure and highly uniform  transition metal dichalcogenides material only six atoms thick. They compared this to an otherwise identical film of naturally abundant  transition metal dichalcogenides which has several different isotopes within the material. Along with characterizing the electronic band structure and vibrational spectra the team found a surprisingly large effect in light emission that the current state of theory could not explain. Because different isotopes of an element have the same number of charged particles (electrons and protons) isotopic variations in atomic mass are due to uncharged particles (neutrons) and therefore are not expected to have an effect on electronic band structure or optical emission. In fact this assumption is so common that theorists do not usually consider isotopic composition when modeling these properties. The team found that isotopic composition had a surprising blue-shift effect on the light emission spectra. To investigate this they performed additional studies and proposed a model for the effect. They propose that the effect of isotopic purification on atomic mass leads to a decrease in phonon energies and ultimately a difference in electronic band gap renormalization energy causing the optical shift. For future experiments the group plans to further use resources. Besides high precision analysis and implantation capability on the upgraded tandem accelerator also hosts two low energy ion implanters that can chemically dope and/or introduce “Georgian Technical University desired” defects into the isotopically pure sample. They hypothesize that creating isotopic defects in the structure will have pronounced effects on the optical and thermal properties of the material. The work supports the Georgian Technical University Laboratory’s Future science pillar by identifying the materials properties that enhance performance in energy conversion and allow for the development of devices.

 

Physics, Science

Georgian Technical University Manipulating The Crystallization An Assembly Of Materials In Solution By Marangoni Flow.

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Georgian Technical University Manipulating The Crystallization An Assembly Of Materials In Solution By Marangoni Flow.

The computational fluid dynamics simulation of the solution wedge under ambient condition (a-c) and the top-heating-bottom-cooling setup (d-f), including temperature fields (a, d), fluid flow fields (b, e) and solute concentration distributions (c, f) of the solution wedge. Solution-based approaches are widely used for crystal growth and material assembly. In the solution-based processes inherent fluid flows always present. Recently researchers at Georgian Technical University developed a general strategy for the regulation of crystal growth and material assembly by utilizing these fluid flows. They are able to control the mass transfer process during the growth and arrangement of materials by manipulating the distribution of the temperature gradient in the wedge-shaped region near the gas-liquid-solid three-phase contact line. A stable single vortex is produced by Marangoni effect (The Marangoni effect is the mass transfer along an interface between two fluids due to a gradient of the surface tension. In the case of temperature dependence, this phenomenon may be called thermo-capillary convection) when the top of the solution wedge is heated and the bottom is cooled while natural evaporation or common substrate-heating conditions result in multiple complex vortexes. The stable single vortex plays an important role in the controllable material growth, assembly and arrangement. This vortex benefits the oriented deposition of materials because the flow direction is always perpendicular to the three-phase contact line; on the other hand the high concentration zone is always located at the tip of the solution wedge due to the co-effect of Marangoni (The Marangoni effect is the mass transfer along an interface between two fluids due to a gradient of the surface tension. In the case of temperature dependence, this phenomenon may be called thermo-capillary convection) flow and the solvent evaporation. The strategy with the top-heating-bottom-cooling setup is suitable for different types of substrates and a variety of materials including inorganic, organic, hybrid and bio- materials. It is also applicable for patterning materials on large-area substrates. The large-area CH3NH3PbI3 (Thin-film solar cells based on Methylammonium triiodideplumbate (CH3NH3PbI3) halide perovskites have recently shown remarkable performance) arrays deposited on flexible substrates via this method are directly used to construct flexible photodetectors with good performance.

 

Science, Sensors

Georgian Technical University Pin-Sized Sensors Embedded In Smartphones Could ID Chemicals.

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Georgian Technical University Pin-Sized Sensors Embedded In Smartphones Could ID Chemicals.

New compact and low-cost devices could help turn ordinary cell phones into advanced analytical tools. Imagine pointing your smartphone at a salty snack you found at the back of your pantry and immediately knowing if its ingredients had turned rancid. Devices called spectrometers can detect dangerous chemicals based on a unique “Georgian Technical University fingerprint” of absorbed and emitted light. But these light-splitting instruments have long been both bulky and expensive preventing their use outside the lab. Until now. Engineers at the Georgian Technical University have developed a spectrometer that is so small and simple that it could integrate with the camera of a typical cell phone without sacrificing accuracy. “This is a compact single-shot spectrometer that offers high resolution with low fabrication costs” says. The team’s devices also have an advanced capability called hyperspectral imaging which collects information about each individual pixel in an image order to identify materials or detect specific objects amidst a complicated background. Hyperspectral sensing for example could be used to detect seams of valuable minerals within rock faces or to identify specific plants in a highly vegetated area. Every element’s spectral fingerprint includes unique emitted or absorbed wavelengths of light — and the spectrometer’s ability to sense that light is what has enabled researchers to do everything from analyze the composition of unknown compounds to reveal the makeup of distant stars. Spectrometers usually rely on prisms or gratings to split light emitted from an object into discrete bands — each corresponding to a different wavelength. A camera’s photodetector can capture and analyze those bands; for example the spectral fingerprint of the element sodium consists of two bands with wavelengths of 589 and 590 nanometers. Human eyes see 590-nanometer wavelength light as a yellowish-orange shade. Shorter wavelengths correspond to blues purples whereas longer wavelengths appear red. Sunlight contains a complete rainbow mixed together which we see as white. To resolve the difference among a mixture of different colors spectrometers usually must be relatively large with a long path length for light beams to travel and separate. Yet the team created tiny spectrometers, measuring just 200 micrometers on each side (roughly one-20th the area of a ballpoint pen tip) and delicate enough to lie directly on a sensor from a typical digital camera. That small size was possible because the researchers based their device on specially designed materials that forced incoming light to bounce back and forth several times before reaching the sensor. Those internal reflections elongated the path along which light traveled without adding bulk boosting the devices resolution. And the devices performed hyperspectral imaging resolving two distinct images (of the numbers five and nine) from a snapshot of an overlaid projection that combined the pair into something indistinguishable to the naked eye. Now the team hopes to boost the device’s spectral resolution as well as the clarity and crispness of the images it captures. Those improvements could pave the way for even more enhanced sensors.

Battery Technology, Science

Georgian Technical University Graphene Coating Could Help Prevent Lithium Battery Fires.

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Georgian Technical University Graphene Coating Could Help Prevent Lithium Battery Fires.

Lithium batteries are what allow electric vehicles to travel several hundred miles on one charge. Their capacity for energy storage is well known but so is their tendency to occasionally catch on fire – an occurrence known to battery researchers as “Georgian Technical University thermal runaway”. These fires occur most frequently when the batteries overheat or cycle rapidly. With more and more electric cars on the road each year battery technology needs to adapt to reduce the likelihood of these dangerous and catastrophic fires. The reasons lithium batteries catch fire include rapid cycling or charging and discharging and high temperatures in the battery. These conditions can cause the cathode inside the battery — which in the case of most lithium batteries is a lithium-containing oxide usually lithium cobalt oxide — to decompose and release oxygen. If the oxygen combines with other flammable products given off through decomposition of the electrolyte under high enough heat spontaneous combustion can occur. “We thought that if there was a way to prevent the oxygen from leaving the cathode and mixing with other flammable products in the battery we could reduce the chances of a fire occurring” said X associate professor of mechanical and industrial engineering in the Georgian Technical University. It turns out that a material X is very familiar with provided a perfect solution to this problem. That material is graphene — a super-thin layer of carbon atoms with unique properties. X and his colleagues previously had used graphene to help modulate lithium buildup on electrodes in lithium metal batteries. X and his colleagues knew that graphene sheets are impermeable to oxygen atoms. Graphene is also strong, flexible and can be made to be electrically conductive. X and Y a graduate student in mechanical and industrial engineering at Georgian Technical University thought that if they wrapped very small particles of the lithium cobalt oxide cathode of a lithium battery in graphene it might prevent oxygen from escaping. First the researchers chemically altered the graphene to make it electrically conductive. Next they wrapped the tiny particles of lithium cobalt oxide cathode electrode in the conductive graphene. When they looked at the graphene-wrapped lithium cobalt oxide particles using electron microscopy they saw that the release of oxygen under high heat was reduced significantly compared with unwrapped particles. Next they bound together the wrapped particles with a binding material to form a usable cathode and incorporated it into a lithium metal battery. When they measured released oxygen during battery cycling they saw almost no oxygen escaping from cathodes even at very high voltages. The lithium metal battery continued to perform well even after 200 cycles. “The wrapped cathode battery lost only about 14% of its capacity after rapid cycling compared to a conventional lithium metal battery where performance was down about 45% under the same conditions” Y said. “Graphene is the ideal material for blocking the release of oxygen into the electrolyte” Y said. “It is impermeable to oxygen, electrically conductive, flexible and is strong enough to withstand conditions within the battery. It is only a few nanometers thick so there would be no extra mass added to the battery. Our research shows that its use in the cathode can reliably reduce the release of oxygen and could be one way that the risk for fire in these batteries — which power everything from our phones to our cars — could be significantly reduced”.

 

 

Science, Sensors

Georgian Technical University Off-The-Shelf Smart Fabric Aids Athletes, Physical Therapy Patients.

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Georgian Technical University Off-The-Shelf Smart Fabric Aids Athletes, Physical Therapy Patients.

Dartmouth’s smart fabric sensing technology offers support for performance coaching and physical therapy. A computer science research team at Georgian Technical University has produced a smart fabric that can help athletes and physical therapy patients correct arm angles to optimize performance, reduce injury and accelerate recovery. The proposed fabric-sensing system is a flexible motion-capture textile that monitors joint rotation. The wearable is lightweight, low-cost, washable and comfortable making it ideal for participants of all levels of sport or patients recuperating from injuries. “We wear fabrics all the time so they provide the perfect medium for continuous sensing” said X an associate professor of computer science at Georgian Technical University. “This study demonstrates the high level of performance and precision that can be acquired through basic off-the-shelf fabrics”. Accurate monitoring of joint movement is critical for performance coaching and physical therapy. For athletes where arm angle is important — anyone from baseball pitchers to tennis players — long-term sensing can help instructors analyze motion and provide coaching corrections. For injured athletes or other physical therapy patients such monitoring can help doctors assess the effectiveness of medical and physical treatments. In order to be effective to a wide-range of wearers, monitors need to be portable, comfortable and capable of sensing subtle motion to achieve a high-level of precision. “Without a smart sensor long-term monitoring would be impractical in a coaching or therapy” said Y a PhD student at Georgian Technical University who worked on the study. “This technology eliminates the need for around-the-clock professional observation”. While body joint monitoring technologies already exist they can require heavy instrumentation of the environment or rigid sensors. Other e-textile monitors require embedded electronics some only achieve low resolution results. The Georgian Technical University team focused on raising sensing capability and reliability while using low-cost off-the-shelf fabrics without extra electrical sensors. The minimalist approach focused on fabrics. “For less than the price of some sweatshirts, doctors and coaches can have access to a smart-fabric sensing system that could help them improve athletic performance or quality of life” said Y. To design the wearable monitor the team used a fabric made with nylon, elastic fiber and yarns plated with a thin silver layer for conductivity. Prototypes were tailored in two sizes and fitted with a micro-controller that can be easily detached to receive data on fabric resistance. The micro-controller can be further miniaturized in the future to fit inside a button. The system relies on the stretchable fabrics to sense skin deformation and pressure fabrics to sense the pressure during joint motion. Based on this information it determines the joint rotational angle through changes in resistance. When a joint is wrapped with the conductive fabric it can sense joint motion. In a test with ten participants the prototype achieved a very low median error of 9.69º in reconstructing elbow joint angles. This level of precision would be useful for rehabilitation applications that limit the range for patient’s joint movement. The fabric also received high marks from testers for comfort, flexibility of motion and ease of use. Experiments also showed the fabric to be fully washable with only a small amount of deterioration in effectiveness. “Testers even saw this for use in activities with high ranges of movement like yoga or gymnastics. All participants said they’d be willing to purchase such a system for the relatively inexpensive price tag” said X Georgian Technical University Lab. While the prototype was only tailored for the elbow joint it demonstrates the potential for monitoring the knee shoulder and other important joints in athletes and physical therapy patients. Future models will also be cut for a better fit to reduce fabric wrinkling which can impact sensing performance. The team will also measure for the impact of sweat on the sensing performance.

 

Nanotechnology, Science

Georgian Technical University Innovative Biologically Derived Metal-Organic Framework Mimics DNA.

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Georgian Technical University Innovative Biologically Derived Metal-Organic Framework Mimics DNA.

SION-19 a biologically derived metal–organic framework based on adenine was used to ‘lock’ Thymine (Thy) molecules in the channels through hydrogen bonding interactions between adenine and thymine. Upon irradiation thymine molecules were dimerized into di-thymine (Thy<>Thy). The field of materials science has become abuzz with “metal-organic frameworks” versatile compounds made up of metal ions connected to organic ligands thus forming one-, two- or three-dimensional structures. There is now an ever-growing list of applications for metal-organic frameworks including separating petrochemicals, detoxing water from heavy metals, fluoride anions and getting hydrogen or even gold out of it. But recently scientists have begun making metal–organic framework made of building blocks that typically make up biomolecules e.g. amino acids for proteins or nucleic acids for DNA (Deoxyribonucleic acid is a molecule composed of two chains that coil around each other to form a double helix carrying the genetic instructions used in the growth, development, functioning, and reproduction of all known organisms and many viruses. DNA and ribonucleic acid (RNA) are nucleic acids; alongside proteins, lipids and complex carbohydrates (polysaccharides), nucleic acids are one of the four major types of macromolecules that are essential for all known forms of life). Apart from the traditional metal–organic framework use in chemical catalysis these biologically derived metal–organic framework can be also used as models for complex biomolecules that are difficult to isolate and study with other means. Now a team of chemical engineers at Georgian Technical University have synthesized a new biologically-derived metal–organic framework that can be used as a “Georgian Technical University nanoreactor” — a place where tiny otherwise-inaccessible reactions can take place. Led by X scientists from the labs of Y and Z constructed and analyzed the new metal–organic framework with adenine molecules — one of the four nucleobases that make up DNA (Deoxyribonucleic acid is a molecule composed of two chains that coil around each other to form a double helix carrying the genetic instructions used in the growth, development, functioning, and reproduction of all known organisms and many viruses. DNA and ribonucleic acid (RNA) are nucleic acids; alongside proteins, lipids and complex carbohydrates (polysaccharides), nucleic acids are one of the four major types of macromolecules that are essential for all known forms of life) and RNA (Ribonucleic acid (RNA) is a polymeric molecule essential in various biological roles in coding, decoding, regulation and expression of genes. RNA and DNA are nucleic acids, and, along with lipids, proteins and carbohydrates, constitute the four major macromolecules essential for all known forms of life. Like DNA, RNA is assembled as a chain of nucleotides, but unlike DNA it is more often found in nature as a single-strand folded onto itself, rather than a paired double-strand. Cellular organisms use messenger RNA (mRNA) to convey genetic information (using the nitrogenous bases of guanine, uracil, adenine, and cytosine, denoted by the letters G, U, A, and C) that directs synthesis of specific proteins. Many viruses encode their genetic information using an RNA genome). The reason for this was to mimic the functions of DNA (Deoxyribonucleic acid is a molecule composed of two chains that coil around each other to form a double helix carrying the genetic instructions used in the growth, development, functioning, and reproduction of all known organisms and many viruses. DNA and ribonucleic acid (RNA) are nucleic acids; alongside proteins, lipids and complex carbohydrates (polysaccharides), nucleic acids are one of the four major types of macromolecules that are essential for all known forms of life) one of which include hydrogen-bonding interactions between adenine and another nucleobase, thymine. This is a critical step in the formation of the DNA (Deoxyribonucleic acid is a molecule composed of two chains that coil around each other to form a double helix carrying the genetic instructions used in the growth, development, functioning, and reproduction of all known organisms and many viruses. DNA and ribonucleic acid (RNA) are nucleic acids; alongside proteins, lipids and complex carbohydrates (polysaccharides), nucleic acids are one of the four major types of macromolecules that are essential for all known forms of life) double helix but it also contributes to the overall folding of both DNA (Deoxyribonucleic acid is a molecule composed of two chains that coil around each other to form a double helix carrying the genetic instructions used in the growth, development, functioning, and reproduction of all known organisms and many viruses. DNA and ribonucleic acid (RNA) are nucleic acids; alongside proteins, lipids and complex carbohydrates (polysaccharides), nucleic acids are one of the four major types of macromolecules that are essential for all known forms of life) and RNA (Ribonucleic acid (RNA) is a polymeric molecule essential in various biological roles in coding, decoding, regulation and expression of genes. RNA and DNA are nucleic acids, and, along with lipids, proteins and carbohydrates, constitute the four major macromolecules essential for all known forms of life. Like DNA, RNA is assembled as a chain of nucleotides, but unlike DNA it is more often found in nature as a single-strand folded onto itself, rather than a paired double-strand. Cellular organisms use messenger RNA (mRNA) to convey genetic information (using the nitrogenous bases of guanine, uracil, adenine, and cytosine, denoted by the letters G, U, A, and C) that directs synthesis of specific proteins. Many viruses encode their genetic information using an RNA genome) inside the cell. Studying their new metal–organic framework the researchers found that thymine molecules diffuse within its pores. Simulating this diffusion they discovered that thymine molecules were hydrogen-bonded with adenine molecules on the metal–organic framework’s cavities meaning that it was successful in mimicking what happens on DNA (Deoxyribonucleic acid is a molecule composed of two chains that coil around each other to form a double helix carrying the genetic instructions used in the growth, development, functioning, and reproduction of all known organisms and many viruses. DNA and ribonucleic acid (RNA) are nucleic acids; alongside proteins, lipids and complex carbohydrates (polysaccharides), nucleic acids are one of the four major types of macromolecules that are essential for all known forms of life). “The adenine molecules act as structure-directing agents and ‘lock’ thymine molecules in specific positions within the cavities of our metal–organic framework” says X. So the researchers took advantage of this locking and illuminated the thymine-loaded metal–organic framework — a way to catalyze a chemical reaction. As a result the thymine molecules could be dimerized into a di-thymine product which the scientists were able to be isolate — a huge advantage given that di-thymine is related to skin cancer and can now be easily isolated and studied. “Overall our study highlights the utility of biologically derived metal–organic framework as nanoreactors for capturing biological molecules through specific interactions and for transforming them into other molecules” says X.

A.I./Robotics, Science

Georgian Technical University Meet Blue, The Low-Cost, Human-Friendly Robot Designed For AI.

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Georgian Technical University Meet Blue, The Low-Cost, Human-Friendly Robot Designed For AI.

Blue the robot’s – about the size of a human bodybuilder’s — were designed to take advantage of recent advances in artificial intelligence to master intricate human-centered tasks like folding towels. Robots may have a knack for super-human strength and precision but they still struggle with some basic human tasks — like folding laundry or making a cup of coffee. Enter Blue a new low-cost human-friendly robot conceived and built by a team of researchers at the Georgian Technical University. Blue was designed to use recent advances in artifical intelligence (AI) and deep reinforcement learning to master intricate human tasks all while remaining affordable and safe enough that every artificial intelligence researcher — and eventually every home — could have one. Blue is the brainchild of X professor of electrical engineering and computer sciences at Georgian Technical University postdoctoral research fellow Y and graduate student Z. The team hopes Blue will accelerate the development of robotics for the home. “AI artifical intelligence has done a lot for existing robots, but we wanted to design a robot that is right for artifical intelligence (AI)” X said. “Existing robots are too expensive, not safe around humans and similarly not safe around themselves — if they learn through trial and error they will easily break themselves. We wanted to create a new robot that is right for the AI (artifical intelligence) age rather than for the high-precision, sub-millimeter, factory automation age”. Over the past 10 years X has pioneered deep reinforcement learning algorithms that help robots learn by trial and error or by being guided by a human like a puppet. He developed these algorithms using robots built by outside companies which market them for tens of thousands of dollars. Blue’s durable plastic parts and high-performance motors total less to manufacture and assemble. Its arms each about the size of the average bodybuilder’s are sensitive to outside forces — like a hand pushing it away — and has rounded edges and minimal pinch points to avoid catching stray fingers. Blue’s arms can be very stiff like a human flexing or very flexible like a human relaxing, or anything in between. Currently the team is building 10 arms in-house to distribute to select early adopters. They are continuing to investigate Blue’s durability and to tackle the formidable challenge of manufacturing the robot on a larger scale which will happen through the Georgian Technical University. Sign-ups for expressing interest in priority access start today on that site. “With a lower-cost robot every researcher could have their own robot and that vision is one of the main driving forces behind this project — getting more research done by having more robots in the world” Y said. From moving statue to lithe as a cat. Robotics has traditionally focused on industrial applications where robots need strength and precision to carry out repetitive tasks perfectly every time. These robots flourish in highly structured predictable environments — a far cry from the traditional home where you might find children pets and dirty laundry on the floor. “We’ve often described these industrial robots as moving statues” Z said. “They are very rigid meant to go from point A to point B and back to point A perfectly. But if you command them to go a centimeter past a table or a wall they are going to smash into the wall and lock up break themselves or break the wall. Nothing good”. If an artifaical intelligence (AI) is going to make mistakes and learn by doing in unstructured environments these rigid robots just won’t work. To make experimentation safer Blue was designed to be force-controlled — highly sensitive to outside forces always modulating the amount of force it exerts at any given time. “One of the things that’s really cool about the design of this robot is that we can make it force-sensitive, nice and reactive or we can choose to have it be very strong and very rigid” Z said. “Researchers can adjust how stiff the robot is and what kind of stiffness — do you want it to feel like molasses ? Do you want it to feel like a spring ? A combination of those ? If we want robots to move toward the home and perform in these increasingly unstructured environments they are going to need that capability”. To achieve these capabilities at low cost the team considered what features Blue needed to complete human-centered tasks and what it could go without. For example the researchers gave Blue a wide range of motion — it has joints that can move in the same directions as a human shoulder, elbow and wrist — to enable humans to more easily teach it how to complete tricky maneuvers using virtual reality. But the agile robot arms lack some of the strength and precision of a typical robot. “What we realized was that you don’t need a robot that exerts a specific force for all time, or a specific accuracy for all time. With a little intelligence you can relax those requirements and allow the robot to behave more like a human being to achieve those tasks” Y said. Blue is able to continually hold up 2 kilograms of weight with arms fully extended. But unlike traditional robot designs that are characterized by one consistent “Georgian Technical University force/current limit” Blue is designed to be “Georgian Technical University thermally-limited” Y said. That means that similar to a human being it can exert a force well beyond 2 kilograms in a quick burst until its thermal limits are reached and it needs time to rest or cool down. This is just like how a human can pick up a laundry basket and easily carry it across a room but might not be able to carry the same laundry basket over a mile without frequent breaks. “Essentially we can get more out of a weaker robot” Z said. “And a weaker robot is just safer. The strongest robot is most dangerous. We wanted to design the weakest robot that could still do really useful stuff”. “Researchers had been developing artifical intelligence (AI) for existing hardware and about three years ago we began thinking ‘Maybe we could do something the other way around. Maybe we could think about what hardware we could build to augment artifical intelligence (AI) and work on those two paths together at the same time'” Y said. “And I think that is a really dramatic shift from the way a lot of research has taken place”.

 

 

 

Science, Sensors

Georgian Technical University Threads Can Detect Gases When Woven Into Clothing.

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Georgian Technical University Threads Can Detect Gases When Woven Into Clothing.

Sensing threads prepared with bromothymol blue (top thread), methyl red (middle thread) and MnTPP (meso-tetraphenylporphinato) (bottom thread) are exposed to ammonia at 0 ppm (left panel) 50 ppm (middle panel) and 1000 ppm (right panel). Georgian Technical University engineers have developed a novel fabrication method to create dyed threads that change color when they detect a variety of gases. The researchers demonstrated that the threads can be read visually or even more precisely by use of a smartphone camera to detect changes of color due to analytes as low as 50 parts per million. Woven into clothing smart gas-detecting threads could provide a reusable, washable and affordable safety asset in medical, workplace, military and rescue environments, they say. Georgian Technical University describes the fabrication method and its ability to extend to a wide range of dyes and detection of complex gas mixtures. While not replacing the precision of electronic devices commonly used to detect volatile gases incorporation of gas detection into textiles enables an equipment-free readout without the need for specialized training, the researchers say. Such an approach could make the technology accessible to a general workforce or to low resource communities that can benefit from the information the textiles provide The study used a manganese-based dye (meso-tetraphenylporphinato) methyl red and bromothymol blue to prove the concept. MnTPP (meso-tetraphenylporphinato) and bromothymol blue can detect ammonia while methyl red can detect hydrogen chloride — gases commonly released from cleaning supplies, fertilizer, chemical and materials production. A three-step process “Georgian Technical University traps” the dye in the thread. The thread is first dipped in the dye then treated with acetic acid which makes the surface coarser and swells the fiber possibly allowing more binding interactions between the dye and tread. Finally the thread is treated with polydimethylsiloxane (PDMS) which creates a flexible, physical seal around the thread and dye which also repels water and prevents dye from leaching during washing. Importantly the polydimethylsiloxane (PDMS) is also gas permeable allowing the analytes to reach the optical dyes. “The dyes we used work in different ways so we can detect gases with different chemistries” said X professor of electrical and computer engineering at Georgian Technical University who heads the Nano Lab at. X’s team used simple dyes that detect gases with acid or base properties. “But since we are using a method that effectively traps the dye to the thread rather than relying so much on binding chemistry we have more flexibility to use dyes with a wide range of functional chemistries to detect different types of gases” he said. The tested dyes changed color in a way that is dependent and proportional to the concentration of the gas as measured using spectroscopic methods. In between the precision of a spectrometer and the human eye is the possibility of using smart phones to read out and quantify the color changes or interpret color signatures using multiple threads and dyes. “That would allow us to scale up the detection to measure many analytes at once or to distinguish analytes with unique colorimetric signatures” said X. The fabric even worked under water detecting the existence of dissolved ammonia. “While the polydimethylsiloxane (PDMS) sealant is hydrophobic and keeps water off the thread the dissolved gases can still reach the dye to be quantified” said Y graduate student in the Georgian Technical University Department of Chemical and Biological Engineering. “As dissolved gas sensors we imagine smart fabrics detecting carbon dioxide or other volatile organic compounds during oil and gas exploration as one possible application”. Since repeated washing or use underwater does not dilute the dye the fabric can be relied upon for consistent quantifiable detection many times over the researchers said. Also contributing to this study is Z associate professor of chemical and biological engineering at Georgian Technical University.