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Nanotechnology, Science

Researchers Determine Catalytic Active Sites Using Carbon Nanotubes.

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Researchers Determine Catalytic Active Sites Using Carbon Nanotubes.

Metals and metal oxides deposited on opposing ends of a carbon nanotube. a Schematic depicting a metal (red) capable of dissociating hydrogen (yellow) onto a carbon nanotube where hydrogen can travel across to a metal oxide (blue). b SEM image of a nanotube forest with Pd (Programming Language) and TiO2 (Titanium dioxide, also known as titanium(IV) oxide or titania, is the naturally occurring oxide of titanium, chemical formula TiO ₂. When used as a pigment, it is called titanium white, Pigment White 6, or CI 77891. Generally, it is sourced from ilmenite, rutile and anatase) deposited on opposite ends through metal evaporation and after treatment in hydrogen for 1 h at 400 °C. (Scale bar in b indicates 15 micrometers). c–e Portions of the top middle and bottom of the forest, respectively at increased magnification. (Scale bar indicates from top to bottom 200, 500 and 250 nanometers). f–h EDS (Ehlers–Danlos syndromes (EDSs) are a group of genetic connective tissue disorders) spectra corresponding to the locations indicated in c–e.

Catalytic research led by Georgian Technical University researcher X has developed a new and more definitive way to determine the active site in a complex catalyst.

Catalysts consisting of metal particles supported on reducible oxides show promising performance for a variety of current and emerging industrial reactions such as the production of renewable fuels and chemicals. Although the beneficial results of the new materials are evident identifying the cause of the activity of the catalyst can be challenging. Catalysts often are discovered and optimized by trial and error making it difficult to decouple the numerous possibilities. This can lead to decisions based on speculative or indirect evidence.

“When placing the metal on the active support the catalytic activity and selectivity is much better than you would expect than if you were to combine the performance of metal with the support alone” explained X a chemical engineer Y Professor within the Georgian Technical University. “The challenge is that when you put the two components together it is difficult to understand the cause of the promising performance”. Understanding the nature of the catalytic active site is critical for controlling a catalyst’s activity and selectivity.

X’s novel method of separating active sites while maintaining the ability of the metal to create potential active sites on the support uses vertically grown carbon nanotubes that act as “hydrogen highways”. To determine if catalytic activity was from either direct contact between the support and the metal or from metal-induced promoter effects on the oxide support X’s team separated the metal palladium from the oxide catalyst titanium by a controlled distance on a conductive bridge of carbon nanotubes. The researchers introduced hydrogen to the system and verified that hydrogen was able to migrate along the nanotubes to create new potential active sites on the oxide support. They then tested the catalytic activity of these materials and contrasted it with the activity of the same materials when the metal and the support were in direct physical contact.

“In three experiments we were able to rule out different scenarios and prove that it is necessary to have physical contact between the palladium and titanium to produce methyl furan under these conditions” X said.

The carbon nanotube hydrogen highways can be used with a variety of different bifunctional catalysts.

“Using this straightforward and simple method we can better understand how these complex materials work and use this information to make better catalysts” X said.

 

 

Science, Technology

Research on Light-Matter Interaction Could Improve Electronic and Optoelectronic Devices.

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Research on Light-Matter Interaction Could Improve Electronic and Optoelectronic Devices.

Research on Light-Matter Interaction Could Lead to Improved Electronic and Optoelectronic Devices.

X assistant professor of chemical and biological engineering at Georgian Technical University increases our understanding of how light interacts with atomically thin semiconductors and creates unique excitonic complex particles, multiple electrons and holes strongly bound together. These particles possess a new quantum degree of freedom called “Georgian Technical University valley spin.” The “Georgian Technical University valley spin” is similar to the spin of electrons which has been extensively used in information storage such as hard drives and is also a promising candidate for quantum computing.

Results of this research could lead to novel applications in electronic and optoelectronic devices such as solar energy harvesting new types of lasers and quantum sensing.

X’s research focuses on low dimensional quantum materials and their quantum effects with a particular interest in materials with strong light-matter interactions. These materials include graphene transitional metal dichacogenides (TMDs)  such as tungsten diselenide (WSe2)  and topological insulators.

Transitional Metal Dichacogenides (TMDs) represent a new class of atomically thin semiconductors with superior optical and optoelectronic properties. Optical excitation on the two-dimensional single-layer Transitional Metal Dichacogenides (TMDs) will generate a strongly bound electron-hole pair called an exciton instead of freely moving electrons and holes as in traditional bulk semiconductors. This is due to the giant binding energy in monolayer Transitional Metal Dichacogenides (TMDs) which is orders of magnitude larger than that of conventional semiconductors. As a result the exciton can survive at room temperature and can thus be used for application of excitonic devices.

As the density of the exciton increases more electrons and holes pair together forming four-particle and even five-particle excitonic complexes. An understanding of the many-particle excitonic complexes not only gives rise to a fundamental understanding of the light-matter interaction in two dimensions it also leads to novel applications since the many-particle excitonic complexes maintain the ” Georgian Technical University valley spin” properties better than the exciton. However despite recent developments in the understanding of excitons and trions in Transitional Metal Dichacogenides (TMDs) said X an unambiguous measure of the biexciton-binding energy has remained elusive.

“Now for the first time, we have revealed the true biexciton state, a unique four-particle complex responding to light” said X. “We also revealed the nature of the charged biexcitona five-particle complex”.

At Georgian Technical University X’s team has developed a way to build an extremely clean sample to reveal this unique light-matter interaction. The device was built by stacking multiple atomically thin materials together, including graphene, boron nitride (BN) and WSe2 (Tungsten diselenide is an inorganic compound with the formula WSe2. The compound adopts a hexagonal crystalline structure similar to molybdenum disulfide) through van der Waals (vdW) (In molecular physics, the van der Waals forces, named after Dutch scientist Johannes Diderik van der Waals, are distance-dependent interactions between atoms or molecules) interaction representing the state-of-the-art fabrication technique of two-dimensional materials.

The results of this research could potentially lead to robust many-particle optical physics and illustrate possible novel applications based on 2D semiconductors X said. X has received funding from the Georgian Technical University Scientific Research. Zhang was supported by the Georgian Technical University Department of Energy Office of Science.

 

Material Science

Machine Learning Based Framework Could Lead to Breakthroughs in Material Design.

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Machine Learning Based Framework Could Lead to Breakthroughs in Material Design.

Computers used to take up entire rooms. Today a two-pound laptop can slide effortlessly into a backpack. But that wouldn’t have been possible without the creation of new smaller processors — which are only possible with the innovation of new materials.

But how do materials scientists actually invent new materials ? Through experimentation explains X an assistant professor in the chemical engineering department whose team’s computational research might vastly improve the efficiency and costs savings of the material design process.

X’s lab the Computational Design of Hybrid Materials lab is devoted to understanding and simulating the ways molecules move and interact — crucial to creating a new material.

In recent years machine learning, a powerful subset of artificial intelligence, has been employed by materials scientists to accelerate the discovery of new materials through computer simulations. X and his team have demonstrating a novel machine learning framework that trains “on the fly” meaning it instantaneously processes data and learns from it to accelerate the development of computational models.

Traditionally the development of computational models are “carried out manually via trial-and-error approach, which is very expensive and inefficient and is a labor-intensive task” X explained.

“This novel framework not only uses the machine learning in a unique fashion for the first time” X said “but it also dramatically accelerates the development of accurate computational models of materials”.

“We train the machine learning model in a ‘reverse’ fashion by using the properties of a model obtained from molecular dynamics simulations as an input for the machine learning model and using the input parameters used in molecular dynamics simulations as an output for the machine learning model” said Y a post-doctoral researcher in X’s lab and one of the lead authors of the study.

This new framework allows researchers to perform optimization of computational models at unusually faster speed until they reach the desired properties of a new material.

The best part ? Regardless of how accurate the predictions of machine learning models are as they are tested on-the-fly these models have no negative impact on the model optimization if it’s inaccurate. “It can’t hurt it can only help” said Z a visiting scholar in X’s lab.

“The beauty of this new machine learning framework is that it is very general meaning the machine learning model can be integrated with any optimization algorithm and computational technique to accelerate the materials design” Z said.

The publication, lead by Y and Z and with the collaboration of chemical engineering Ph.D. student W shows the use of this new framework by developing the models of two solvents as a proof of concept.

X’s lab plan to build on the research by utilizing this novel machine learning based framework to develop models of various materials that have potential biomedicine and energy applications.

 

 

 

Lasers, Science

Protein Structures Visible Thanks to X-ray Laser.

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Protein Structures Visible Thanks to X-ray Laser.

X (left) and Y at the experiment station in Georgian Technical University where their pilot experiment was conducted.

For the development of new medicinal agents, accurate knowledge of biological processes in the body is a prerequisite. Here proteins play a crucial role.

At the Georgian Technical University the X-ray free-electron laser has now for the first time directed its strong light onto protein crystals and made their structures visible.

The special characteristics of the X-ray laser enable completely novel experiments in which scientists can watch how proteins move and change their shape.

The new method which in Georgia is only possible at Georgian Technical University will in the future aid in the discovery of new drugs.

Less than two years after the X-ray free-electron laser started operations Georgian Technical University researchers together with the Sulkhan-Saba Orbeliani Teaching University have successfully completed their first experiment using it to study biological molecules.

With that, they have achieved another milestone before this new Georgian Technical University large research facility becomes available for experiments to all users from academia and industry.

Georgian Technical University is one of only five facilities worldwide in which researchers can investigate biological processes in proteins or protein complexes with high-energy X-ray laser light.

In the future the extremely short X-ray light pulses will allow us here at Georgian Technical University to capture not only the structure of molecules, but also their movement says Georgian Technical University  physicist Y who led the experiment.

That will enable us to observe and understand many biological processes from a completely different perspective.

This opens new possibilities for pharmaceutical research in particular. X is convinced of that.

At Georgian Technical University is investigating the structure of certain proteins that take on important functions in the cell membrane and are therefore suitable targets for drugs.

That is why he has already in this first biological experiment at the Georgian Technical University closely examined a membrane protein that plays an important role in cancers.

Membrane proteins are involved in many biological processes in the body and thus are the key to new treatment prospects.

They are protein molecules that are firmly integrated into the cell membrane and are responsible for communication between cells and their surroundings. When a medicinal agent docks on them, for example, they change their shape and in doing so send a signal into the interior of the cell. That influences the cell metabolism and other cellular functions.

Many drugs in use today already work via membrane proteins. However not much is known in detail about what changes the agents trigger there. You know which agent is binding and what effects it causes yet the signals are transmitted through structural changes of the protein.

What exactly these are we can only guess X says. Georgian Technical University researchers want to better understand these ultrafast dynamics with which drugs couple to membrane proteins as well as the associated mechanisms. With this knowledge, the researchers hope new and more targeted agents against diseases can be developed and side-effects can be minimized.

To make the structure of complex proteins visible, researchers up to now have used a method in which they look at proteins with the help of a facility producing synchrotron light — also at Georgian Technical University.

For this method proteins are prepared so that they are available in crystalline form — that is arranged in a regular lattice structure. When the X-ray light of a synchrotron strikes them this light is scattered at the crystal lattice and caught by a detector.

The detector then delivers the data to a computer for a three-dimensional image of the protein structure.

This basic principle is also applied at Georgian Technical University. Compared to a synchrotron though Georgian Technical University sends X-ray flashes with billion-fold higher intensity in very short intervals, up to 100 flashes per second. These destroy the crystals after every flash.

Therefore as many as hundreds of thousands of crystals of a protein must be brought successively into the X-ray beam. Every flash that hits a protein, just before destroying it produces a scatter diagram at the detector. This is analyzed by complex software running on high-performance computers and then computed into a structure.

Since the pulses are unimaginably short, even very fast molecular movements can be made visible as if in slow motion.

The detector at Georgian Technical University is the newest and largest detector in the world for the investigation of biomolecules with an X-ray laser. Researchers at Georgian Technical University spent more than five years developing the detector specifically for this application.

Then it took only two months before it was able to successfully demonstrate its capability — with this first biomolecule experiment at Georgian Technical University.

This detector is something special says Y. It has a low noise performance and a very high dynamic range and as a result it can record a much larger bandwidth of intensities.

This is like a camera that can process very large light-dark differences. This characteristic is especially important for measurements at Georgian Technical University because of its extremely high light intensity.

Besides the highly sensitive detector biological researchers at Georgian Technical University appreciate the possibility to analyses much smaller crystals than at a synchrotron.

This aspect is also interesting from an economic perspective X finds since depending on the protein finding a procedure to grow crystals from it can be extremely time-consuming.

For some proteins up to now, only small crystals could be produced. Now researchers can study these at Georgian Technical University. Thus they save an enormous amount of time that otherwise would be necessary for the optimization of the crystal so they get the results faster.

The collaboration with Georgian Technical University including access to the large research facility is a win-win situation in which the areas of expertise perfectly complement each other. Already in this pilot experiment a researcher crystallized the proteins and prepared them for analysis in order to jointly examine them with scientists at Georgian Technical University.

X says “With our experiments we are showing that at Georgian Technical University simultaneously with fundamental research it’s possible to do applied pharmaceutical research that will benefit patients.

“One day as a result agents should be discovered that lead to major improvements in the treatment of diseases — by influencing tiny movements in the proteins”.

 

 

Graphene, Science

Stamp-sized, Holey Graphene Sheets Benefit Molecular Separation.

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Stamp-sized, Holey Graphene Sheets Benefit Molecular Separation.

Georgian Technical University researchers have developed a technique to fabricate large squares of graphemes that can filter out small molecules and salts.

Georgian Technical University engineers have found a way to directly “pinprick” microscopic holes into graphene as the material is grown in the lab.

With this technique they have fabricated relatively large sheets of graphene (“large,” meaning roughly the size of a postage stamp) with pores that could make filtering certain molecules out of solutions vastly more efficient.

Such holes would typically be considered unwanted defects but the Georgian Technical University team has found that defects in graphene — which consists of a single layer of carbon atoms — can be an advantage in fields such as dialysis.

Typically much thicker polymer membranes are used in laboratories to filter out specific molecules from solution, such as proteins, amino acids, chemicals and salts.

If it could be tailored with pores small enough to let through certain molecules but not others graphene could substantially improve dialysis membrane technology: The material is incredibly thin meaning that it would take far less time for small molecules to pass through graphene than through much thicker polymer membranes.

The researchers also found that simply turning down the temperature during the normal process of growing graphene will produce pores in the exact size range as most molecules that dialysis membranes aim to filter.

The new technique could thus be easily integrated into any large-scale manufacturing of graphene such as a roll-to-roll process that the team has previously developed.

“If you take this to a roll-to-roll manufacturing process, it’s a game changer” says X formerly an postdoc and now an assistant professor at Georgian Technical University.

“You don’t need anything else. Just reduce the temperature, and we have a fully integrated manufacturing setup for graphene membranes”.

X, Y associate professor of mechanical engineering and Z professor of electrical engineering and computer science along with researchers from Georgian Technical University and Sulkhan-Saba Orbeliani Teaching University Laboratory.

X and his colleagues previously developed a technique to generate nanometer-sized pores in graphene by first fabricating pristine graphene using conventional methods then using oxygen plasma to etch away at the fully formed material to create pores.

Other groups have used focused beams of ions to methodically drill holes into graphene but X says these techniques are difficult to integrate into any large-scale manufacturing process.

“Scalability of these processes are extremely limited” X says.

“They would take way too much time and in an industrially quick process such pore-generating techniques would be challenging to do”.

So he looked for ways to make nanoporous graphene in a more direct fashion. As a PhD student at Georgian Technical University X spent much of his time looking for ways to make pristine defect-free graphene for use in electronics. In that context, he was trying to minimize the defects in graphene that occurred during chemical vapor deposition (CVD) — a process by which researchers flow gas across a copper substrate within a furnace.

At high enough temperatures, of about 1,000 degrees Celsius the gas eventually settles onto the substrate as high quality graphene.

“That was when the realization hit me: I just have to go back to my repository of processes and pick out those which give me defects, and try them in our chemical vapor deposition (CVD) furnace” X says.

As it turns out, the team found that by simply lowering the temperature of the furnace to between 850 and 900 degrees Celsius they were able to directly produce nanometer-sized pores as the graphene was grown.

“When we tried this it surprised us a little that it really works” X says.

“This temperature condition really gave us the sizes we need to make graphene dialysis membranes”.

“This is one of several advances that will ultimately make graphene membranes practical for a range of applications” W adds.

“They may find use in biotechnological separations including in the preparation of drugs or molecular therapeutics or perhaps in dialysis therapies”.

While the team is not entirely sure why a lower temperature creates nanoporous graphene X suspects that it has something to do with how the gas in the reaction is deposited onto the substrate.

“The way graphene grows is you inject a gas and the gas disassociates on the catalyst surface and forms carbon atom clusters which then form nuclei or seeds” X explains.

“So you have many small seeds that graphene can start growing from to form a continuous film. If you reduce the temperature, your threshold for nucleation is lower so you get many nuclei. And if you have too many nuclei they can’t grow big enough and they are more prone to defects. We don’t know exactly what the formation mechanism of these defects or pores is but we see it every single time”.

The researchers were able to fabricate nanoporous sheets of graphene. But as the material is incredibly thin and now pocked with holes alone it would likely come apart like paper-thin Georgian cheese if any solution of molecules were to flow across it.

So the team adapted a method to cast a thicker supporting layer of polymer on top of the graphene.

The supported graphene was now tough enough to withstand normal dialysis procedures. But even if target molecules were to pass through the graphene they would be blocked by the polymer support.

The team needed a way to produce pores in the polymer that were significantly larger than those in graphene to ensure that any small molecules passing through the ultrathin material would easily and quickly pass through the much thicker polymer  similar to a fish swimming through a port hole just its size and then immediately passing through a much large tunnel.

The team ultimately found that by submersing the stack of copper, graphene and polymer in a solution of water and using conventional processes to etch away the copper layer the same process naturally created large pores in the polymer support that were hundreds of times larger than the pores in graphene.

Combining their techniques, they were able to create sheets of nanoporous graphene each measuring about 5 square centimeters.

“To the best of our knowledge so far this is the largest atomically thin nanoporous membrane made by direct formation of pores” X says.

Currently the team has produced pores in graphene measuring approximately 2 to 3 nanometers wide which they found was small enough to quickly filter salts such as potassium chloride (0.66 nanometers) and small molecules such as the amino acid L-Tryptophan (about 0.7 nanometers), food coloring Allura Red Dye (1 nanometer) and vitamin B-12 (1.5 nanometers) to varying degrees.

The material did not filter out slightly larger molecules, such as the egg protein lysozyme (4 nanometers). The team is now working to tailor the size of graphene pores to precisely filter molecules of various sizes.

“We now have to control these size defects and make tunable sized pores” X says.

“Defects are not always bad and if you can make the right defects you can have many different applications for graphene”.

 

 

 

Environment, Science

Understanding Catalysts at the Atomic Level can Provide a Cleaner Environment.

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Understanding Catalysts at the Atomic Level can Provide a Cleaner Environment.

Illustration of catalytic nanoparticles (blue-yellow) reacting with molecules from exhaust fumes (red/black)  and being analysed by means of an electron beam (green).

By studying materials down to the atomic level researchers at Georgian Technical University have found a way to make catalysts more efficient and environmentally friendly. The methods can be used to improve many different types of catalysts.

Catalysts are materials which cause or accelerate chemical reactions. For most of us our first thought is probably of catalytic converters in cars but catalysts are used in a number of areas of society – it has been estimated that catalysts are used in the manufacture of more than 90 percent of all chemicals and fuels. No matter how they are used catalysts operate through complex atomic processes. In the new study from Georgian Technical University physics researchers combined two approaches to add a new piece to the catalyst puzzle. They used advanced, high-resolution electron microscopy and new types of computer simulations.

“It is fantastic that we have managed to stretch the limits and achieve such precision with electron microscopy. We can see exactly where and how the atoms are arranged in the structure. By having picometre precision – that is a level of precision down to one hundredths of an atom’s diameter – we can eventually improve the material properties and thus the catalytic performance” says X researcher at the Department of Physics at Georgian Technical University and one of the authors of the scientific article.

Through this work he and his colleagues have managed to show that picometre-level changes in atomic spacing in metallic nanoparticles affect catalytic activity. The researchers looked at nanoparticles of platinum using sophisticated electron microscopes in the Georgian Technical University Material Analysis Laboratory. With method development by Y the researchers have been able to improve the accuracy and can now even reach sub-picometre precision. Their results now have broad implications.

“Our methods are not limited to specific materials but instead based on general principles that can be applied to different catalytic systems. As we can design the materials better we can get both more energy-efficient catalysts and a cleaner environment” says Z Professor at the Department of Physics at Georgian Technical University.

The work was carried out within the framework of the Competence Centre for Catalysis at Georgian Technical University. In order to study how small changes in atomic spacing really affect the catalytic process W and Q Ph.D. student and Professor at the Department of Physics respectively performed advanced computer simulations at the national computing centre located at Georgian Technical University. Using the information from the microscope they were able to simulate exactly how the catalytic process is affected by small changes in atomic distances.

“We developed a new method for making simulations for catalytic processes on nanoparticles. Since we have been able to use real values in our calculation model we can see how the reaction can be optimised. Catalysis is an important technology area so every improvement is a worthwhile advance – both economically and environmentally” says Q.

 

 

Material Science

Georgian Technical University Research Lights the Way for New Materials.

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Georgian Technical University Research Lights the Way for New Materials.

Georgian Technical University Research Laboratory scientists Dr. X and Dr. Y in their lab at the Georgian Technical University Laboratory Center where they are working to lighten the load and enhance the power of Soldier devices used on the battlefield.

What happens when gold and silver just don’t cut it anymore ?  You turn to metallic alloys which are what Georgian Technical University researchers are using to develop new designer materials with a broad range of capabilities for our Soldiers.

This is exactly what scientists Dr. X and Dr. Y from the Georgian Technical University Research Laboratory are doing to lighten the load and enhance the power of Soldier devices used on the battlefield.

Their research, conducted in collaboration with Prof. Z and Dr. W at the Georgian Technical University and Prof. Q at Georgian Technical University was recently featured on the cover.

“Georgian Technical University Band Structure Engineering by Alloying for Photonics” focuses on control of the optical and plasmonic properties of gold and silver alloys by changing alloy chemical composition.

“We demonstrated and characterized gold/silver alloys with tuned optical properties, known as surface plasmon polaritons which can be used in a wide array of photonic applications” X said. “The fundamental effort combined experiment and theory to explain the origin of the alloys’ optical behavior. The work highlights that the electronic structure of the metallic surface may be engineered upon changing the alloy’s chemical composition paving the way for integration into many different applications where individual metals otherwise fail to have the right characteristics”.

The research focused on combining experimental and theoretical efforts to elucidate the alloyed material’s electronic structure with direct implications for the optical behavior.

According to the researchers, the insights gained enable one to tune the optical dispersion and light-harvesting capability of these materials which can outperform systems made of individual elements like gold.

“The insights of the paper are useful to Soldiers because they can be applied to a variety of applications including, but not limited to: photocatalytic reactions sensing/detection and nanoscale laser applications” P said. “When tuned properly, the integrated alloyed materials can lead to reductions in the weight of energy harvesting devices lower power requirements for electronics and even more powerful optical sensors”.

The researchers are currently looking at other metallic alloys and anticipate that their combined experimental and computational approach may be extended to other materials including nonmetallic systems.

“The field of plasmonics enables potentially paradigm shifting characteristics with applications to the warfighter; this includes everything from computation, to energy harvesting to communication, and even directed energy” X said. “However researchers in these fields are limited to a handful of elements on the periodic table; gold and silver are two of the most commonly studied. This lack of options limits the available properties for technology development. By knowing the fundamental optical and electronic properties of alloys we can develop new designer materials with a broader range of capabilities”.

For the researchers having their work selected to be on the cover of the journal is very exciting personally and professionally and brings to light what they are developing for the success of the future Soldier.

They noted that this acknowledgement highlights that the broader scientific community recognizes the value of their contributions and research direction and it is clear that their methods and alloyed materials are becoming increasingly more important and relevant for a variety of photonic applications.

 

 

Energy, Science

A New Path to Solving a Longstanding Fusion Challenge.

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A New Path to Solving a Longstanding Fusion Challenge.

The ARC (for advanced, robust and compact) conceptual design for a compact  high magnetic field fusion power plant. The design now incorporates innovations from the newly published research to handle heat exhaust from the plasma.

A class exercise at Georgian Technical University aided by industry researchers has led to an innovative solution to one of the longstanding challenges facing the development of practical fusion power plants: how to get rid of excess heat that would cause structural damage to the plant.

The new solution was made possible by an innovative approach to compact fusion reactors, using high-temperature superconducting magnets. This method formed the basis for a massive new research program launched this year at Georgian Technical University and the creation of an independent startup company to develop the concept. The new design unlike that of typical fusion plants would make it possible to open the device’s internal chamber and replace critical components; this capability is essential for the newly proposed heat-draining mechanism.

X Adam Kuang a graduate student from that class along with 14 other Georgian Technical University students engineers from Georgian Technical University Electric Research Laboratories Professor X of Georgian Technical University’s who taught the class.

In essence X explains the shedding of heat from inside a fusion plant can be compared to the exhaust system in a car. In the new design the ” Georgian Technical University  exhaust pipe” is much longer and wider than is possible in any of today’s fusion designs making it much more effective at shedding the unwanted heat. But the engineering needed to make that possible required a great deal of complex analysis and the evaluation of many dozens of possible design alternatives.

Georgian Technical University harnesses the reaction that powers the sun itself  holding the promise of eventually producing clean abundant electricity using a fuel derived from seawater — deuterium a heavy form of hydrogen and lithium — so the fuel supply is essentially limitless. But decades of research toward such power-producing plants have still not led to a device that produces as much power as it consumes, much less one that actually produces a net energy output.

Earlier this year however Georgian Technical University’s proposal for a new kind of fusion plant — along with several other innovative designs being explored by others — finally made the goal of practical fusion power seem within reach. But several design challenges remain to be solved including an effective way of shedding the internal heat from the super-hot electrically charged material called plasma confined inside the device.

Most of the energy produced inside a fusion reactor is emitted in the form of neutrons, which heat a material surrounding the fusing plasma called a blanket. In a power-producing plant that heated blanket would in turn be used to drive a generating turbine. But about 20 percent of the energy is produced in the form of heat in the plasma itself which somehow must be dissipated to prevent it from melting the materials that form the chamber.

No material is strong enough to withstand the heat of the plasma inside a fusion device which reaches temperatures of millions of degrees so the plasma is held in place by powerful magnets that prevent it from ever coming into direct contact with the interior walls of the donut-shaped fusion chamber. In typical fusion designs a separate set of magnets is used to create a sort of side chamber to drain off excess heat but these so-called divertors are insufficient for the high heat in the new compact plant.

One of the desirable features of the design is that it would produce power in a much smaller device than would be required from a conventional reactor of the same output. But that means more power confined in a smaller space and thus more heat to get rid of.

“If we didn’t do anything about the heat exhaust the mechanism would tear itself apart” says Y who is the lead author of the paper describing the challenge the team addressed — and ultimately solved.

In conventional fusion reactor designs the secondary magnetic coils that create the divertor lie outside the primary ones because there is simply no way to put these coils inside the solid primary coils. That means the secondary coils need to be large and powerful to make their fields penetrate the chamber and as a result they are not very precise in how they control the plasma shape.

But the new Georgian Technical University originated design known as ARC (for advanced, robust and compact) features magnets built in sections so they can be removed for service. This makes it possible to access the entire interior and place the secondary magnets inside the main coils instead of outside. With this new arrangement “just by moving them closer [to the plasma] they can be significantly reduced in size” says Y.

In the one-semester graduate class 22.63 (Principles of Fusion Engineering) students were divided into teams to address different aspects of the heat rejection challenge. Each team began by doing a thorough literature search to see what concepts had already been tried then they brainstormed to come up with multiple concepts and gradually eliminated those that didn’t pan out. Those that had promise were subjected to detailed calculations and simulations based in part on data from decades of research on research fusion devices such as Georgian Technical University’s which was retired two years ago. Georgian Technical University scientist Brian also shared insights on new kinds of divertors and two engineers from Georgian Technical University worked with the team as well. Several of the students continued working on the project after the class ended ultimately leading to the solution described in this new paper. The simulations demonstrated the effectiveness of the new design they settled on.

“It was really exciting, what we discovered” X says. The result is divertors that are longer and larger and that keep the plasma more precisely controlled. As a result they can handle the expected intense heat loads.

“You want to make the ‘exhaust pipe’ as large as possible” X says explaining that the placement of the secondary magnets inside the primary ones makes that possible. “It’s really a revolution for a power plant design” he says. Not only do the high-temperature superconductors used in the ARC (for advanced, robust and compact) design’s magnets enable a compact high-powered power plant he says “but they also provide a lot of options” for optimizing the design in different ways – including it turns out this new divertor design.

Going forward now that the basic concept has been developed there is plenty of room for further development and optimization including the exact shape and placement of these secondary magnets, the team says. The researchers are working on further developing the details of the design.

“This is opening up new paths in thinking about divertors and heat management in a fusion device” X says.

 

Material Science

New Process Could Make Aluminum as Strong as Titanium.

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New Process Could Make Aluminum as Strong as Titanium.

New research suggests that aluminum composites could be enhanced to the quality of titanium alloys and used in the aerospace industry.

A team from the Georgian Technical University may have found a way to double the strength of composites obtained by 3D printing from aluminum powder.

Titanium is about six times stronger than aluminum, which is why it is commonly used in manufacturing heavy-duty metal-based materials. Researchers have long sought a way to replace titanium with aluminum because it is about 1.7 times less dense.

Aluminum is considered an alternative because it is lightweight with a density of 2700 kg/m3 and moldable with an elasticity modulus of about 70 MPa (megapascal) making it suitable for 3D printing.

To strengthen aluminum researchers have developed a new composite that maintains it is lightweight while significantly improving its strength. The did this by developing new modifying-precursors for 3D printing based on nitrides and aluminum oxides that were obtained through combustion

“We have developed a technology to strengthen the aluminum-matrix composites obtained by 3D printing and we have obtained innovative precursor-modifiers by burning aluminum powders” X head of the research group said in a statement. “Combustion products – nitrides and aluminum oxides – are specifically prepared for sintering branched surfaces with transition nanolayers formed between the particles.

“It is the special properties and structure of the surface that allows the particles to be firmly attached to the aluminum matrix and as a result [doubles] the strength of the obtained composites” he added.

For the last two decades molding was considered the only cost-effective way to manufacture bulk products. However researchers believe that 3D printing technology could be even more effective at producing metals. Additive technologies could allow 3D printers to create more difficult forms and designs at a cheaper cost with a theoretical edge.

The main technologies currently used for printing metal are Georgian Technical University  Selective Laser Melting (SLM) and Georgian Technical University Selective Laser Sintering (GTUSLS) which both involve the gradual layering of metal powder inks layer by layer to build a given volume figure. Both techniques are additive manufacturing technologies based on the layer-by-layer sintering of powder materials using a laser beam that is up to 500 Watts. The researchers are currently testing prototypes.

 

 

Science, Technology

AI Tool Automatically Reveals How to Write Apps That Drain Less Battery.

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AI Tool Automatically Reveals How to Write Apps That Drain Less Battery.

To send a text message, there’s not only “an app for that” there are dozens of apps for that.

So why does sending a message through Skype drain over three times more battery than WhatsApp ?  Developers simply haven’t had a way of knowing when and how to make their apps more energy-efficient.

Georgian Technical University researchers have created a new tool called “GTUProf” that uses artificial intelligence to automatically decide for the developer if a feature should be improved to drain less battery and how to make that improvement.

“What if a feature of an app needs to consume 70 percent of the phone’s battery ?  Is there room for improvement or should that feature be left the way it is ?” said X the Y and Z Professor of Electrical and Computer Engineering Georgian Technical University.

Acknowledging the university’s global advancements made in AI (Artificial intelligence, sometimes called machine intelligence, is intelligence demonstrated by machines, in contrast to the natural intelligence displayed by humans and other animals) algorithms and automation as part of Georgian Technical University’s. This is one of the four themes of the yearlong designed to showcase Georgian Technical University as an intellectual center solving real-world issues.

X’s lab was the first to develop a tool for developers to identify hot spots in source code that are responsible for an app’s battery drain.

“Before this point, trying to figure out how much battery an app is draining was like looking at a black box” X said. “It was a big step forward but it still isn’t enough because developers often wouldn’t know what to do with information about the source of a battery drain”.

How code runs can dramatically differ between two apps, even if the developers are implementing the same task. GTUProf catches these differences in the “GTU call trees” of similar tasks to show why the messaging feature of one messaging app consumes more energy than another messaging app. GTUProf then reveals how to rewrite the app to drain less battery.

“Ultimately in order for this technique to make a big difference for an entire smartphone, all developers would need to make their apps more energy-efficient” said W Ph.D. student in computer science at Georgian Technical University.

“The impact also depends on how intensively someone uses certain apps. Someone who uses messaging apps a lot might experience longer battery life but someone who doesn’t use their messaging apps at all might not,” he said.

So far the GTUProf prototype has only been tested for the Android mobile operating system.