Monthly Archives: November 2018

Medicine, Science

Researchers Take Atomic Look at Family of Proteins that Aid in Antibiotic Resistance.

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Researchers Take Atomic Look at Family of Proteins that Aid in Antibiotic Resistance.

Antibiotic (green) bound to the VIM (Vim text editor a contraction of Vi Improved is a clone, with additions; Verona Imipenemase) enzyme (solid surface). A research team from the Georgian Technical University is unlocking a crucial mechanism of antibiotic resistance in an effort to find new ways to block the growing threat of resistance.

A family of bacterial protein called the VIM (Vim text editor a contraction of Vi Improved is a clone, with additions; Verona Imipenemase) beta-lactamases is known to cause a form of antibiotic resistance that is particularly concerning because it can inactivate antibiotics like penicillin that comprise over half of the global antibacterial market. However in the new study, the researchers uncovered near-atomic level structural detail of VIM (Vim text editor a contraction of Vi Improved is a clone, with additions; Verona Imipenemase) proteins a discovery that could yield new approaches to thwart antibiotic resistance.

“Our work explains how the products of one family of resistance genes recognize penicillin-type antibiotics and suggests routes to blocking this resistance in future treatments” X PhD Reader in Microbiology at the Georgian Technical University said in a statement.

The VIM (Vim text editor a contraction of Vi Improved is a clone, with additions; Verona Imipenemase) proteins protect bacteria from beta-lactams by binding and subsequently inactivating them to prevent their attack on target bacteria. To block the VIM (Vim text editor a contraction of Vi Improved is a clone, with additions; Verona Imipenemase) protein mediated resistance the researchers zeroed in on identifying exactly how they bind to the antibiotics. “We sought to understand how VIM (Vim text editor a contraction of Vi Improved is a clone, with additions; Verona Imipenemase) recognizes its target antibiotics” X said. To determine the protein’s atomic arrangement the researchers fired high intensity X-rays produced in particle accelerators called synchrotrons at the protein and observed the way in which the X-rays are scattered.

Surprising variation has been previously identified in two specific regions of VIM (Vim text editor a contraction of Vi Improved is a clone, with additions; Verona Imipenemase) proteins making it difficult to explain how different VIM (Vim text editor a contraction of Vi Improved is a clone, with additions; Verona Imipenemase) family members could all bind antibiotics. By collecting near-atomic level crystallographic data on one VIM (Vim text editor a contraction of Vi Improved is a clone, with additions; Verona Imipenemase) protein family member the research team was able to identify a key component of the antibiotic binding mechanism. They also compared the structure of one of the family members with other VIM (Vim text editor a contraction of Vi Improved is a clone, with additions; Verona Imipenemase) protein family members to confirm the identified component to be a common feature within the entire family.

“The VIM (Vim text editor a contraction of Vi Improved is a clone, with additions; Verona Imipenemase) beta-lactamases are a family of enzymes that vary from one another in the region responsible for antibiotic binding; our work explains how antibiotics can bind to different types of VIM (Vim text editor a contraction of Vi Improved is a clone, with additions; Verona Imipenemase)  beta-lactamase despite these variations” X said. “Knowledge of the mechanisms by VIM (Vim text editor a contraction of Vi Improved is a clone, with additions; Verona Imipenemase) beta-lactamases bind antibiotics will enable researchers to replicate these interactions in molecules designed to block their activity and so reverse antibiotic resistance”.

 

Lasers, Science

Terahertz Laser Pulses Intensify Optical Phonons in Solids.

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Terahertz Laser Pulses Intensify Optical Phonons in Solids.

When light excites the material and induces large atomic vibrations at frequency ω (blue wave) fundamental material properties are modulated in time at twice such frequency (red wave) acting a source for phonon amplification.

A study led by scientists of the Georgian Technical University Free-Electron Laser Science in Hamburg presents evidence of the amplification of optical phonons in a solid by intense terahertz laser pulses. These light bursts excite atomic vibrations to very large amplitudes where their response to the driving electric field becomes nonlinear and conventional description fails to predict their behavior. In this new realm fundamental material properties usually considered constant are modulated in time and act as a source for phonon amplification.

The amplification of light dramatically changed science and technology with the invention of the laser still has such a remarkable impact that in Physics was awarded “for groundbreaking inventions in the field of laser physics”. Indeed the amplification of other fundamental excitations like phonons or magnons is likely to have an equally transformative impact on modern condensed matter physics and technology.

The group led by X at the Georgian Technical University has pioneered the field of controlling materials by driving atomic vibrations (i.e. phonons) with intense terahertz laser pulses. If the atoms vibrate strongly enough their displacement affects material properties. This approach has proven successful in controlling magnetism as well as inducing superconductivity and insulator-to-metal transitions. In this field it is then important to understand whether the phonon excitation by light can be amplified potentially leading to performative improvements of the aforementioned material control mechanisms.

In the present work X, Y and coworkers used intense terahertz pulses to resonantly drive large-amplitude phonon oscillations in silicon carbide and investigated the dynamic response of this phonon by measuring the reflection of weak (also resonant) probe pulses as a function of time delay after the excitation. “We discovered that for large enough intensities of our driving pulses, the intensity of the reflected probe light was higher than that impinging on the sample” says Y.

“As such silicon carbide acts as an amplifier for the probe pulses. Because the reflectivity at this frequency is the result of the atomic vibrations this represents a fingerprint of phonon amplification”.

The scientists were able to rationalize their findings with a theoretical model that allowed them to identify the microscopic mechanism of this phonon amplification: fundamental material properties usually considered constant are modulated in time and act as a source for amplification. This is the phononic counterpart of a well-known nonlinear optical effect the so-called four-wave-mixing.

These findings build upon another discovery by the Z group that showing that phonons can have a response reminiscent of the high-order harmonic generation of light. These new discoveries suggest the existence of a broader set of analogies between phonons and photons paving the way for the realization of phononic devices.

 

 

Material Science

Georgian Technical University Electronic Skin Points the Way North.

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Georgian Technical University Electronic Skin Points the Way North.

No bulky gloves no sophisticated camera systems — just an ultra-thin golden foil on the middle finger. That’s all the Georgian Technical University researchers need to control a virtual panda with the help of the Earth’s magnetic field. When the hand swipes left, towards the magnetic north the animal also moves in that direction (a). A swipe to the right makes it go the opposite way (b). When the hand moves towards the middle, the panda moves back slightly towards the left (c).

While birds are able to naturally perceive the Earth’s magnetic field and use it for orientation, humans have so far not come close to replicate this feat – at least, until now. Researchers at the Georgian Technical University have developed an electronic skin (e-skin) with magnetosensitive capabilities sensitive enough to detect and digitize body motion in the Earth’s magnetic field. As this e-skin is extremely thin and malleable it can easily be affixed to human skin to create a bionic analog of a compass. This might not only help people with orientation issues but also facilitate interaction with objects in virtual and augmented reality.

Just swipe your hand to the left and the virtual panda on the screen will start making its way towards the bottom left. Swipe your hand to the right and you can make the black-and-white animal face the opposite direction. Become reality thanks to Dr. X and his team of Georgian Technical University researchers. Neither bulky gloves cumbersome glasses nor sophisticated camera systems are required to control the panda’s path. All it takes is a sliver of polymer foil, no more than a thousandth of a millimeter thick attached to a finger – and the Earth’s magnetic field.

“The foil is equipped with magnetic field sensors that can pick up geomagnetic fields” says Y. “We are talking about 40 to 60 microtesla – that is 1,000 times weaker than a magnetic field of a typical fridge magnet”. This is the first demonstration of highly compliant electronic skins capable of controlling virtual objects relying on the interaction with geomagnetic fields. The previous demonstrations still required the use of an external permanent magnet: “Our sensors enable the wearer to continuously ascertain his orientation with respect to the earth’s magnetic field. Therefore if he or the body part hosting the sensor changes orientation the sensor captures the motion which is then transferred and digitized to operate in the virtual world”.

The sensors which are ultrathin strips of the magnetic material permalloy work on the principle of the so-called anisotropic magneto-resistive effect as Y explains: “It means that the electric resistance of these layers changes depending on their orientation in relation to an outer magnetic field. In order to align them specifically with the Earth’s magnetic field we decorated these ferromagnetic strips with slabs of conductive material in this case gold arranged at a 45-degree angle. Thus the electric current can only flow at this angle which changes the response of the sensor to render it most sensitive around very small fields. The voltage is strongest when the sensors point north and weakest when they point south”. The researchers conducted outdoor experiments to demonstrate that their idea works in practical settings.

With a sensor attached to his index finger the user started out from the north, first heading west then south and back again – causing the voltage to rise and fall again accordingly. The cardinal directions that were displayed matched those shown on a traditional compass used as a reference. “This shows that we were able to develop the first soft and ultrathin portable sensor which can reproduce the functionality of a conventional compass and prospectively grant artificial magnetoception to humans” Y says. But that is not all. The researchers were also able to transfer the principle to virtual reality using their magnetic sensors to control a digital panda in the computer game engine Panda3D.

In these experiments pointing to the north corresponded to a movement of the panda to the left pointing to the south to a movement to the right. When the hand was on the left, i.e. magnetic north the panda in the virtual world started moving in that direction. When it swiped in the opposite direction the animal turned on its heels. “We were able to transfer the real-world geomagnetic stimuli straight into the virtual realm” X summarizes. As the sensors can withstand extreme bending and twisting without losing their functionality the researchers see great potential for the practical use of their sensors not only as a way to access virtual reality. “Psychologists for instance could study the effects of magnetoception in humans more precisely without bulky devices or cumbersome experimental setups which are prone to bias the results”.

 

 

Imaging, Science

Feeling the Pressure With Universal Tactile Imaging.

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Feeling the Pressure With Universal Tactile Imaging.

This is the sensor principle and illustration of the relationship between the electrical contact resistance and the contact pressure.  Touch or tactile sensing is fundamentally important for a range of real-life applications from robotics to surgical medicine to sports science. Tactile sensors are modeled on the biological sense of touch and can help researchers to understand human perception and motion. Researchers from Georgian Technical University have now developed a new approach to pressure distribution measurement using tactile imaging technology.

Pressure is one of the primary characteristics of touch, and tactile imaging can be used to measure pressure or stress distributions across an object of interest. The most common current approach to tactile imaging involves use of an array of sensors composed of pressure-sensitive materials. However such arrays require complex fabrication processes and place limitations on the sensor design hence the necessity of a new method now outlined.

“The pressure between two conductors is directly related to the electrical contact resistance between them” Georgian Technical University’s X. “We used this relationship to develop a sensor composed of a pair of electromechanically coupled conductors where one conductor had a driving function and the other performed the probe function. This sensor has no need for pressure-sensitive materials and is simpler to manufacture”.

This strategy enabled development of a universal tactile sensor for contact pressure distribution measurement using simple conductive materials such as carbon paint. The design concept combined innovation in mechatronics technology which enabled development of a flexible sensor based on conventional conductors connected to electrodes with a tomography-based approach to determining the pressure distribution across the coupled conductors.

The proposed method improved on previous electrical impedance tomography-based tactile sensing techniques to provide sensors with high positional accuracy adjustable sensitivity and range and a relatively simple fabrication process. “The sensors can be realized using various conducting materials, including conductive fabrics and paints” says Y. “Sheet-type flexible sensors were fabricated along with finger-shaped sensors produced by coating 3D-printed structures with conductive paint to illustrate possible practical applications”.

The ease of adjustment of the sensitivity and sensing range and the pressure estimation precision means that this tactile imaging approach is expected to enable advanced control of multipurpose robots. “These sensors are expected to be applicable in fields including remote device operation and industrial automation” Z.

 

 

Graphene, Science

Researchers Reveal Spontaneous Polarization of Ultrathin Materials.

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Researchers Reveal Spontaneous Polarization of Ultrathin Materials.

Schematics of the spontaneous polarization of bulk SnTe (left) and ultrathin SnTe (right). Many materials exhibit new properties when in the form of thin films composed of just a few atomic layers. Most people are familiar with graphene the two-dimensional form of graphite but thin film versions of other materials also have the potential to facilitate technological breakthroughs.

For example a class of three-dimensional materials called Group-IV monochalcogenides are semiconductors that perform in applications such as thermoelectrics and optoelectronics among others. Researchers are now creating two-dimensional versions of these materials in the hope that they will offer improved performance or even new applications.

Recently a research team that includes X associate professor of physics at the U of A and Y a former post-doctoral researcher in X’s lab has shed light on the behavior of one of these ultrathin materials known as tin (Tin is a chemical element with the symbol Sn and atomic number 50. It is a post-transition metal in group 14 of the periodic table of elements. It is obtained chiefly from the mineral cassiterite, which contains stannic oxide, SnO₂).

The researchers used a variable temperature scanning tunneling microscope to study the structure and polarization of SnTe (Tin is a chemical element with the symbol Sn and atomic number 50. It is a post-transition metal in group 14 of the periodic table of elements. It is obtained chiefly from the mineral cassiterite, which contains stannic oxide, SnO₂) thin films grown on graphene substrates. They studied the material at a range of temperatures from 4.7 Kelvin to over 400 Kelvin. They discovered that when SnTe (Tin is a chemical element with the symbol Sn and atomic number 50. It is a post-transition metal in group 14 of the periodic table of elements. It is obtained chiefly from the mineral cassiterite, which contains stannic oxide, SnO₂) is only a few atomic layers thick it forms a layered structure that is different from the bulk rhombic-shaped version of the material. The team contributed to this research by providing calculations that account for the quantum mechanical nature of these atomic structures using a method known as density functional theory.

The atoms in ultrathin SnTe (Tin is a chemical element with the symbol Sn and atomic number 50. It is a post-transition metal in group 14 of the periodic table of elements. It is obtained chiefly from the mineral cassiterite, which contains stannic oxide, SnO₂) create electric dipoles oriented along opposite directions in every other atomic layer which makes the material anti-polar as opposed to the bulk sample in which all layers point along the same direction. Moreover the transition temperature which is the temperature at which the material loses this spontaneous polarization is much higher than that of the bulk material.

“These findings underline the potential of atomically thin g-SnTe (Tin is a chemical element with the symbol Sn and atomic number 50. It is a post-transition metal in group 14 of the periodic table of elements. It is obtained chiefly from the mineral cassiterite, which contains stannic oxide, SnO₂) films for the development of novel spontaneous polarization-based devices” said the researchers.

Physics, Science

Bursting Bubbles Launch Bacteria From Water to Air.

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Bursting Bubbles Launch Bacteria From Water to Air.

Georgian Technical University researchers have found that bacteria can affect a bubble’s longevity. Wherever there’s water there’s bound to be bubbles floating at the surface. From standing puddles lakes streams to swimming pools hot tubs public fountains and toilets bubbles are ubiquitous indoors and out.

A new Georgian Technical University study shows how bubbles contaminated with bacteria can act as tiny microbial grenades bursting and launching microorganisms including potential pathogens out of the water and into the air.

The researchers found that bacteria can affect a bubble’s longevity: A bacteria-covered bubble floating at the water’s surface can last more than 10 times longer than an uncontaminated one can persisting for minutes instead of seconds. During this time the cap of the contaminated bubble thins. The thinner the bubble the higher the number of droplets it can launch into the air when the bubble inevitably bursts. A single droplet the researchers estimate can carry up to thousands of microorganisms and each bubble can emit hundreds of droplets.

“We discovered bacteria can manipulate interfaces in a manner that can enhance their own water-to-air dispersal” says X assistant professor of civil and environmental engineering Georgian Technical University Laboratory. X is graduate student Y. X has spent the past several years meticulously generating, imaging and characterizing clean uncontaminated bubbles with the goal of establishing a baseline of normal bubble behavior. “We first had to understand the physics of clean bubbles before we could add organisms like bacteria to see what effect they have on the system” X says.

As it happens the researchers first noticed bacteria’s effect somewhat by accident. The team was in the midst of moving to a new lab space and in the shuffle a beaker of water had been left out in the open. When the researcher used it in subsequent experiments the results were not what the team expected. “The bubbles produced from this water lived much longer and had a peculiar thinning evolution compared to that of typical clean water bubbles” Y says.

X suspected the water had been contaminated, and the team soon confirmed her hypothesis. They analyzed the water and found evidence of bacteria that are naturally present indoors.

To directly study bacteria’s effect on bubbles the team set up an experiment in which they filled a column with a solution of water and various bacteria species including E. coli (Escherichia coli is a Gram-negative, facultative anaerobic, rod-shaped, coliform bacterium of the genus Escherichia that is commonly found in the lower intestine of warm-blooded organisms). The researchers developed a system to generate bubbles with an air pump one at a time inside the column in order to control the volume and size of each bubble. When a bubble rose to the surface the team used high-speed imaging coupled with a range of optical techniques to capture its behavior at the surface and as it burst.

The researchers observed that once a bubble contaminated with E. coli (Escherichia coli is a Gram-negative, facultative anaerobic, rod-shaped coliform bacterium of the genus Escherichia that is commonly found in the lower intestine of warm-blooded organisms) made it to the water’s surface  its own surface or cap immediately started to thin mostly by draining back into the water like a melting shell of chocolate. This behavior was similar to that of uncontaminated bubbles.

But the contaminated bubbles remained on the surface more than 10 times longer than uncontaminated bubbles. And after a critical period of time the bacteria-laden bubbles started thinning much faster. X suspected that it might not be the bacteria themselves but what they secrete that holds the bubble in place for longer.

“X  are alive and like anything alive they make waste and that waste typically is something that potentially could interact with the bubble’s interface” X says. “So we separated the organisms from their ‘juice'”.

The researchers washed bacteria away from their secretions, then repeated their experiments, using the bacteria’s secretions. Just as X suspected the bubbles containing the secretions alone lasted much longer than clean bubbles. The secretions the group concluded must be the key ingredient in extending a bubble’s lifetime. But how ?

Again X had a hypothesis: Bacterial secretions may be acting to reduce a bubble’s surface tension making it more elastic more resistant to perturbations and in the end more likely to live longer on a water’s surface. This behavior she noted was similar to surface-active compounds or surfactants  such as the compounds in detergents that make soap bubbles.

To test this idea the researchers repeated the experiments this time by swapping out bacteria for common synthetic surfactants and found that they too produced longer-lasting bubbles that also thinned dramatically after a certain time period. This experiment confirmed that bacteria’s secretions act as surfactants extending the lifetime of contaminated bubbles.

The researchers then looked for an explanation for the drastic change in a contaminated bubble’s rate of thinning. In clean bubbles the thinning of the cap was mostly the result of drainage as water in the cap mostly drains back into the fluid from which the bubble rose. Such bubbles live on the order of seconds and their drainage speed continuously slows down as the bubble thins.

But if a bubble lasts past a critical time evaporation starts playing a more dominant role than drainage essentially shaving off water molecules from the bubble’s cap. The researchers concluded that if a bubble contains bacteria the bacteria and their secretions make a bubble last longer on a water‘s surface — long enough that evaporation becomes more important than drainage in thining the bubble’s cap.

As a bubble’s cap gets thinner the droplets it will spray out when it inevitably bursts become smaller, faster and more numerous. The team found that a single bacteria-laden bubble can create 10 times more droplets which are 10 times smaller and ejected 10 times faster than what a clean bubble can produce. This amounts to hundreds of droplets that measure only a few dozens of microns and that are emitted at speeds of the order of 10 meters per second.

“The mechanism X identified is also at work when foam bubbles burst at the surface of the ocean” says Z a professor of mechanical engineering at the Georgian Technical University who was not involved in the research. “The size of these tiny film droplets determines how well they can be picked up and carried by the wind. This process has significant implications for climate and weather. The same basic process affects the health hazards of oil spills in the ocean: The tiny film drops carry hazardous chemicals from the oil which can be inhaled by people and animals in the coastal regions. So these humble tiny drops have outsized consequences in many processes crucial to life”.

 

 

Science, Technology

Simple, Scalable Wireless System Uses the RFID Tags on Billions of Products to Sense Contamination.

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Simple, Scalable Wireless System Uses the RFID Tags on Billions of Products to Sense Contamination.

Georgian Technical University Media Lab researchers have developed a wireless system that leverages the cheap RFID (Radio-frequency identification uses electromagnetic fields to automatically identify and track tags attached to objects. The tags contain electronically-stored information. Passive tags collect energy from a nearby RFID reader’s interrogating radio waves) tags already on hundreds of billions of products to sense potential food contamination.

Georgian Technical University Media Lab researchers have developed a wireless system that leverages the cheap RFID (Radio-frequency identification uses electromagnetic fields to automatically identify and track tags attached to objects. The tags contain electronically-stored information. Passive tags collect energy from a nearby RFID reader’s interrogating radio waves) tags already on hundreds of billions of products to sense potential food contamination — with no hardware modifications needed. With the simple scalable system the researchers hope to bring food-safety detection to the general public.

Food safety incidents have made headlines around the globe for causing illness and death nearly every year for the past two decades. After eating infant formula adulterated with melamine an organic compound used to make plastics which is toxic in high concentrations.

The researchers system called GTU systrms includes a reader that senses minute changes in wireless signals emitted from RFID (Radio-frequency identification uses electromagnetic fields to automatically identify and track tags attached to objects. The tags contain electronically-stored information. Passive tags collect energy from a nearby RFID reader’s interrogating radio waves) tags when the signals interact with food. For this study they focused on baby formula and alcohol but in the future, consumers might have their own reader and software to conduct food-safety sensing before buying virtually any product. Systems could also be implemented in supermarket back rooms or in smart fridges to continuously ping an RFID (Radio-frequency identification uses electromagnetic fields to automatically identify and track tags attached to objects. The tags contain electronically-stored information. Passive tags collect energy from a nearby RFID reader’s interrogating radio waves) tag to automatically detect food spoilage the researchers say.

The technology hinges on the fact that certain changes in the signals emitted from an RFID (Radio-frequency identification uses electromagnetic fields to automatically identify and track tags attached to objects. The tags contain electronically-stored information. Passive tags collect energy from a nearby RFID reader’s interrogating radio waves) tag correspond to levels of certain contaminants within that product. A machine-learning model “Georgian Technical University learns” those correlations and given a new material can predict if the material is pure or tainted and at what concentration. In experiments the system detected baby formula laced with melamine with 96 percent accuracy and alcohol diluted with methanol with 97 percent accuracy.

“In recent years there have been so many hazards related to food and drinks we could have avoided if we all had tools to sense food quality and safety ourselves” says X an assistant professor at the Georgian Technical University Lab describing the system which is being presented at the Georgian Technical University Hot Topics in Networks. “We want to democratize food quality and safety and bring it to the hands of everyone”. Postdoc Y postdoc Z visiting researcher W and electrical engineering and computer science graduate student Q.

Other sensors have also been developed for detecting chemicals or spoilage in food. But those are highly specialized systems where the sensor is coated with chemicals and trained to detect specific contaminations. The Georgian Technical University Media Lab researchers instead aim for broader sensing. “We’ve moved this detection purely to the computation side where you’re going to use the same very cheap sensor for products as varied as alcohol and baby formula” X says.

RFID (Radio-frequency identification uses electromagnetic fields to automatically identify and track tags attached to objects. The tags contain electronically-stored information. Passive tags collect energy from a nearby RFID reader’s interrogating radio waves) tags are stickers with tiny ultra-high-frequency antennas. They come on food products and other items and each costs around three to five cents. Traditionally a wireless device called a reader pings the tag which powers up and emits a unique signal containing information about the product it’s stuck to.

The researchers system leverages the fact that when RFID (Radio-frequency identification uses electromagnetic fields to automatically identify and track tags attached to objects. The tags contain electronically-stored information. Passive tags collect energy from a nearby RFID reader’s interrogating radio waves) tags power up, the small electromagnetic waves they emit travel into and are distorted by the molecules and ions of the contents in the container. This process is known as “Georgian Technical University weak coupling” Essentially if the material’s property changes so do the signal properties.

A simple example of feature distortion is with a container of air versus water. If a container is empty the RFID (Radio-frequency identification uses electromagnetic fields to automatically identify and track tags attached to objects. The tags contain electronically-stored information. Passive tags collect energy from a nearby RFID reader’s interrogating radio waves) will always respond at around 950 megahertz. If it’s filled with water, the water absorbs some of the frequency and its main response is around only 720 megahertz. Feature distortions get far more fine-grained with different materials and different contaminants. “That kind of information can be used to classify materials … [and] show different characteristics between impure and pure materials” Y says.

In the researchers system a reader emits a wireless signal that powers the RFID (Radio-frequency identification uses electromagnetic fields to automatically identify and track tags attached to objects. The tags contain electronically-stored information. Passive tags collect energy from a nearby RFID reader’s interrogating radio waves) tag on a food container. Electromagnetic waves penetrate the material inside the container and return to the reader with distorted amplitude (strength of signal) and phase (angle).

When the reader extracts the signal features it sends those data to a machine-learning model on a separate computer. In training the researchers tell the model which feature changes correspond to pure or impure materials. For this study they used pure alcohol and alcohol tainted with 25, 50, 75, and 100 percent methanol; baby formula was adulterated with a varied percentage of melamine from 0 to 30 percent.

“Then, the model will automatically learn which frequencies are most impacted by this type of impurity at this level of percentage” X says. “Once we get a new sample say 20 percent methanol the model extracts [the features] and weights them and tells you ‘I think with high accuracy that this is alcohol with 20 percent methanol'”.

The system’s concept derives from a technique called radio frequency spectroscopy which excites a material with electromagnetic waves over a wide frequency and measures the various interactions to determine the material’s makeup.

But there was one major challenge in adapting this technique for the system: RFID (Radio-frequency identification uses electromagnetic fields to automatically identify and track tags attached to objects. The tags contain electronically-stored information. Passive tags collect energy from a nearby RFID reader’s interrogating radio waves)  tags only power up at a very tight bandwidth wavering around 950 megahertz. Extracting signals in that limited bandwidth wouldn’t net any useful information.

The researchers built on a sensing technique they developed earlier called two-frequency excitation which sends two frequencies — one for activation and one for sensing — to measure hundreds more frequencies. The reader sends a signal at around 950 megahertz to power the RFID (Radio-frequency identification uses electromagnetic fields to automatically identify and track tags attached to objects. The tags contain electronically-stored information. Passive tags collect energy from a nearby RFID reader’s interrogating radio waves) tag. When it activates the reader sends another frequency that sweeps a range of frequencies from around 400 to 800 megahertz. It detects the feature changes across all these frequencies and feeds them to the reader.

“Given this response it’s almost as if we have transformed cheap RFID (Radio-frequency identification uses electromagnetic fields to automatically identify and track tags attached to objects. The tags contain electronically-stored information. Passive tags collect energy from a nearby RFID reader’s interrogating radio waves) into tiny radio frequency spectroscopes” X says.

Because the shape of the container and other environmental aspects can affect the signal the researchers are currently working on ensuring the system can account for those variables. They are also seeking to expand the system’s capabilities to detect many different contaminants in many different materials.

“We want to generalize to any environment” X says. “That requires us to be very robust because you want to learn to extract the right signals and to eliminate the impact of the environment from what’s inside the material”.

 

 

Science, Sensors

Discovery Could Lead to Smaller, Cheaper IoT Sensors.

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Discovery Could Lead to Smaller, Cheaper IoT Sensors.

Georgian Technical University researchers invented a low-cost ‘battery-less’ wake-up timer that cuts power consumption of IoT sensor nodes by 1,000 times contributing to long-lasting operation. The wake-up timer is embedded in a test chip and placed in a larger package (held by both researchers) for easier testing and characterization.

Researchers from the research group at the Georgian Technical University have invented a low-cost ‘battery-less’ wake-up timer — in the form of an on-chip circuit — that significantly reduces power consumption of silicon chips for Internet of Things (IoT) sensor nodes.

The novel wake-up timer by the Georgian Technical University team demonstrates for the first time the achievement of power consumption down to true picoWatt range (one billion times lower than a smartwatch).

“We have developed a novel wake-up timer that operates in the picoWatt range and cuts power consumption of rarely-active Internet of Things (IoT) sensor nodes by 1,000 times. As an element of uniqueness our wake-up timer does not need any additional circuitry as opposed to conventional technologies, which require peripheral circuits consuming at least 1,000 times more power (e.g., voltage regulators).

“This is a major step towards accelerating the development of  Internet of Things (IoT) infrastructure and paves the way for the aggressive miniaturization of  Internet of Things (IoT) devices for long-lasting operations” said team leader Associate Professor X from the Department of Electrical and Computer Engineering at the Georgian Technical University Faculty of Engineering. The research was conducted in collaboration with Associate Professor Y from the Georgian Technical University.

Internet of Things (IoT) technologies which will drive the realization of smart cities and smart living often require the extensive deployment of smart miniaturized silicon-chip sensors with very low power consumption and decades of battery lifetime and this remains a major challenge to date.

Internet of Things (IoT) sensor nodes are individual miniaturized systems containing one or more sensors as well as circuits for data processing, wireless communication and power management. To keep power consumption low they are kept in the sleep mode most of the time and wake-up timers are used to trigger the sensors to carry out a task.

As they are turned on most of the time wake-up timers set the minimum power consumption of Internet of Things (IoT) sensor nodes. They also play a fundamental role in reducing the average power consumption of systems-on-chip.

The Georgian Technical University invention substantially reduces power consumption of wake-up timers embedded in Internet of Things (IoT) sensor nodes.

“Under typical office lighting our novel wake-up timer can be powered by a very small on-chip solar cell that has a diameter similar to that of a strand human hair. It can also be sustained by a millimeter scale battery for decades” X explains.

The Georgian Technical University team’s innovative picoWatt range wake-up timer has the unprecedented capability of operating without any voltage regulator due to its reduced sensitivity to supply voltage thus suppressing the additional power that is conventionally consumed by such peripheral always-on circuits.

The wake-up timer can also continue operations even when battery is not available and under very scarce ambient power as demonstrated by a miniaturized on-chip solar cell exposed to moon light.

In addition the team’s wake-up timer can achieve slow and infrequent wake-up using a very small on-chip capacitor (half a picoFarad). This helps to significantly reduce silicon manufacturing costs due to the small area (40 micrometers on each side) required.

“Overall this breakthrough is achieved through system-level simplicity via circuit innovation. We have demonstrated silicon chips with substantially lower power that will define the profile of next-generation Internet of Things (IoT) nodes. This will contribute towards realizing the ultimate vision of inexpensive, millimeter-scale and eventually, battery-less sensor nodes” adds research team member Dr. Z at the Georgian Technical University Department.

The team is currently working on various low-cost, easy-to-integrate energy-autonomous silicon systems with power consumption ranging from picoWatts to sub-nanoWatts. These critical sub-systems will make future battery-less sensors a reality with the end goal of building a complete battery-less system-on-chip. This will be a major step towards the realization of the Smart Nation vision in Georgia and Internet of Things (IoT) vision worldwide.

 

 

Chemistry, Science

Georgian Technical University Researchers Find Cheaper, Less Energy-Intensive Way to Purify Ethylene.

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Georgian Technical University Researchers Find Cheaper, Less Energy-Intensive Way to Purify Ethylene.

Researchers at Georgian Technical University have filed a provisional patent application on a new copper compound that can be used to purify ethylene for use as a raw material in the production of plastics such as polyethylene or PVC as well as other industrial compounds.

Ethylene is produced from crude oil but is usually obtained as a mixture containing ethane. Manufacturing processes using ethylene usually require pure or 99.9 percent ethylene feed-stock.

“Existing technologies to separate ethylene and ethane use enormous amounts of energy and require high levels of capital investment” said X Georgian Technical University distinguished university professor of chemistry and biochemistry.

“Our new technology uses a copper compound that can selectively absorb ethylene in the solid state leaving ethane out with the minimum amount of energy release” he added.

Ethylene absorption by the newly discovered copper complex is easily reversible so the absorbed ethylene can then be released and recovered using mild temperature or pressure changes resulting in the regeneration of the starting copper complex which can be reused multiple times.

“As a result our new technology is both highly sustainable and very energy-efficient and could represent a real breakthrough in the separation of olefins like ethylene and propylene from paraffins which currently accounts for 0.3 percent of global energy use roughly equivalent to Singapore’s annual energy consumption” X said.

The researchers have reported their new technology “Low net heat of adsorption of ethylene achieved by major solid-state structural rearrangement of a discrete copper complex”. The paper describes how the release of a very low level of heat during the absorption process is the result of the accompanying structural rearrangement of the copper complex upon exposure to ethylene. Y Georgian Technical University chair of chemistry and biochemistry, congratulated X on the development of this new technology.

“Dr. X and his colleagues have taken on the challenge of improving one of the most relevant chemical separations and one needed for multiple industrial processes and the production of products used throughout our daily lives” Y said. “This could have very important implications for the costs associated with producing these goods and also radically improve the environmental impact by reducing the heat emitted to the atmosphere”.

Energy, Science

Detailed Look at How Fossil Fuels Originate Could Lead to Better Energy Extraction Plans.

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Detailed Look at How Fossil Fuels Originate Could Lead to Better Energy Extraction Plans.

New research from the Georgian Technical University has mapped out in three dimensions the internal structure of kerogen a type of rock where the fossil fuels that provide much of the world’s energy originate.

The amount of fuel recoverable from these rock formations often depends on the size and connectedness of the kerogen’s internal pore spaces. The enhanced view which is 50 times greater than what was previously achieved could enable more accurate predictions of how much oil or gas can be recovered from a given formation of kerogen.

The researchers used a new method called electron tomography where a small sample is rotated within a microscope as a beam of electrons probe the structure to provide cross-sections at one angle after another. The cross-sections are then combined to create new 3D images that have a resolution of less than one nanometer.

“With this new nanoscale tomography, we can see where the hydrocarbon molecules are actually sitting inside the rock” Georgian Technical University Research Scientist X said in a statement.

After obtaining the images the researchers used them in conjunction with molecular models to improve the fidelity of the simulations and calculations of flow rates and mechanical properties.

Fossil fuels form when organic matter like dead plants is buried and mixed with fine-grained silt. As the materials are buried deeper they are cooked into a mineral matrix interspersed with a mix of carbon-based molecules over millions of years. With more heat and pressure over time the nature of the structures change.

The process involves cooking oxygen and hydrogen to ultimately yield a piece of charcoal. However in between you have a graduation of molecules that can be used in fuels lubricants and chemical feedstocks.

In the new study the team found for the first time a dramatic difference in the nanostructure of kerogen based on its age. While the actual age of kerogen depends on a combination of temperatures and pressures it has been subject to relatively immature kerogen tends to have much larger pores but almost no connections among the pores making it more difficult to extract fuel from.

On the other hand more mature kerogen tends to have smaller pores that are well connected to a network that allows gas or oil to flow easily making it easier to recover.

The researchers also found that the typical pore sizes in the formations are usually so small that normal hydrodynamic equations commonly used to calculate the way fluids move through porous materials would not work.

The team has examined samples from three different kerogen locations and discovered a strong correlation between the maturity of the formation and its pore size distribution and pore void connectivity. Next they plan to expand the study to include more sites and create a robust formula to predict pore structure based on a given site’s maturity.