For the past decade, disordered rock salt has been studied as a potential breakthrough cathode material for use in lithium-ion batteries and a key to creating low-cost, high-energy storage for everything from cell phones to electric vehicles to renewable energy storage.A new MIT study is making sure the material fulfills that promise.Led by Ju Li, the Tokyo Electric Power Company Professor in Nuclear Engineering and professor of materials science and engineering, a team of researchers describe a new class of partially disordered rock salt cathode, integrated with polyanions — dubbed disordered rock salt-polyanionic spinel, or DRXPS — that delivers high energy density at high voltages with significantly improved cycling stability.“There is typically a trade-off in cathode materials between energy density and cycling stability … and with this work we aim to push the envelope by designing new cathode chemistries,” says Yimeng Huang, a postdoc in the Department of Nuclear Science and Engineering and first author of a&nbsp;<a href="https://www.nature.com/articles/s41560-024-01615-6" target="_blank">paper describing the work published today in&nbsp;Nature Energy</a>. “(This) material family has high energy density and good cycling stability because it integrates two major types of cathode materials, rock salt and polyanionic olivine, so it has the benefits of both.”Importantly, Li adds, the new material family is primarily composed of manganese, an earth-abundant element that is significantly less expensive than elements like nickel and cobalt, which are typically used in cathodes today.“Manganese is at least five times less expensive than nickel, and about 30 times less expensive than cobalt,” Li says. “Manganese is also the one of the keys to achieving higher energy densities, so having that material be much more earth-abundant is a tremendous advantage.”<h2>A possible path to renewable energy infrastructure</h2>That advantage will be particularly critical, Li and his co-authors wrote, as the world looks to build the renewable energy infrastructure needed for a low- or no-carbon future.Batteries are a particularly important part of that picture, not only for their potential to decarbonize transportation with electric cars, buses, and trucks, but also because they will be essential to addressing the intermittency issues of wind and solar power by storing excess energy, then feeding it back into the grid at night or on calm days, when renewable generation drops.Given the high cost and relative rarity of materials like cobalt and nickel, they wrote, efforts to rapidly scale up electric storage capacity would likely lead to extreme cost spikes and potentially significant materials shortages.“If we want to have true electrification of energy generation, transportation, and more, we need earth-abundant batteries to store intermittent photovoltaic and wind power,” Li says. “I think this is one of the steps toward that dream.”That sentiment was shared by Gerbrand Ceder, the&nbsp;Samsung&nbsp;Distinguished&nbsp;Chair&nbsp;in Nanoscience and Nanotechnology Research and a professor of materials science and engineering at the University of California at Berkeley.“Lithium-ion batteries are a critical part of the clean energy transition,” Ceder says. “Their continued growth and price decrease depends on the development of inexpensive, high-performance cathode materials made from earth-abundant materials, as presented in this work.”<h2>Overcoming obstacles in existing materials</h2>The new study addresses one of the major challenges facing disordered rock salt cathodes — oxygen mobility.While the materials have long been recognized for offering very high capacity — as much as 350 milliampere-hour per gram — as compared to traditional cathode materials, which typically have capacities of between 190 and 200 milliampere-hour per gram, it is not very stable.The high capacity is contributed partially by oxygen redox, which is activated when the cathode is charged to high voltages. But when that happens, oxygen becomes mobile, leading to reactions with the electrolyte and degradation of the material, eventually leaving it effectively useless after prolonged cycling.To overcome those challenges, Huang added another element — phosphorus — that essentially acts like a glue, holding the oxygen in place to mitigate degradation.“The main innovation here, and the theory behind the design, is that Yimeng added just the right amount of phosphorus, formed so-called polyanions with its neighboring oxygen atoms, into a cation-deficient rock salt structure that can pin them down,” Li explains. “That allows us to basically stop the percolating oxygen transport due to strong covalent bonding between phosphorus and oxygen … meaning we can both utilize the oxygen-contributed capacity, but also have good stability as well.”That ability to charge batteries to higher voltages, Li says, is crucial because it allows for simpler systems to manage the energy they store.“You can say the quality of the energy is higher,” he says. “The higher the voltage per cell, then the less you need to connect them in series in the battery pack, and the simpler the battery management system.”<h2>Pointing the way to future studies</h2>While the cathode material described in the study could have a transformative impact on lithium-ion battery technology, there are still several avenues for study going forward.Among the areas for future study, Huang says, are efforts to explore new ways to fabricate the material, particularly for morphology and scalability considerations.“Right now, we are using high-energy ball milling for mechanochemical synthesis, and … the resulting morphology is non-uniform and has small average particle size (about 150 nanometers). This method is also not quite scalable,” he says. “We are trying to achieve a more uniform morphology with larger particle sizes using some alternate synthesis methods, which would allow us to increase the volumetric energy density of the material and may allow us to explore some coating methods … which could further improve the battery performance. The future methods, of course, should be industrially scalable.”In addition, he says, the disordered rock salt material by itself is not a particularly good conductor, so significant amounts of carbon — as much as 20 weight percent of the cathode paste — were added to boost its conductivity. If the team can reduce the carbon content in the electrode without sacrificing performance, there will be higher active material content in a battery, leading to an increased practical energy density.“In this paper, we just used Super P, a typical conductive carbon consisting of nanospheres, but they’re not very efficient,” Huang says. “We are now exploring using carbon nanotubes, which could reduce the carbon content to just 1 or 2 weight percent, which could allow us to dramatically increase the amount of the active cathode material.”Aside from decreasing carbon content, making thick electrodes, he adds, is yet another way to increase the practical energy density of the battery. This is another area of research that the team is working on.“This is only the beginning of DRXPS research, since we only explored a few chemistries within its vast compositional space,” he continues. “We can play around with different ratios of lithium, manganese, phosphorus, and oxygen, and with various combinations of other polyanion-forming elements such as boron, silicon, and sulfur.”With optimized compositions, more scalable synthesis methods, better morphology that allows for uniform coatings, lower carbon content, and thicker electrodes, he says, the DRXPS cathode family is very promising in applications of electric vehicles and grid storage, and possibly even in consumer electronics, where the volumetric energy density is very important.<hr>This work was supported with funding from the Honda Research Institute USA Inc. and the Molecular Foundry at Lawrence Berkeley National Laboratory, and used resources of the National Synchrotron Light Source II at Brookhaven National Laboratory and the Advanced Photon Source at Argonne National Laboratory. The work was carried out, in part, using MIT.nano’s facilities.&nbsp;

An artistic illustration of the integration between two distinct battery cathode structures, rock salt (blue polyhedra) and polyanion olivine (red/yellow polyhedra). A novel hybrid structure is obtained by integrating polyanions (yellow polyhedra) into a rock salt (blue polyhedra) structure. Photo: Yimeng Huang/Department of Nuclear Science and Engineering

A new family of integrated rock salt-polyanion cathodes opens door to low-cost, high-energy storage.

Study of disordered rock salts leads to battery breakthrough

A view into how nanoscale building blocks can rearrange into different organized structures on command is now possible with an approach that combines an electron microscope, a small sample holder with microscopic channels, and computer simulations, according to a new study by researchers at the University of Michigan and Indiana University.The approach could eventually enable smart materials and coatings that can switch between different optical, mechanical and electronic properties.“One of my favorite examples of this phenomenon in nature is in chameleons,” said <a href="https://che.engin.umich.edu/people/dwyer-tobias/" target="_blank" rel="noreferrer noopener">Tobias Dwyer</a>, U-M doctoral student in chemical engineering and co-first author of the study published in Nature Chemical Engineering. “Chameleons change color by altering the spacing between nanocrystals in their skin. The dream is to design a dynamic and multifunctional system that can be as good as some of the examples that we see in biology.”The imaging technique lets researchers watch how nanoparticles react to changes in their environment in real time, offering an unprecedented window into their assembly behavior.<img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNzI1MzIxMzE4NjkzLWZsb3ctY2VsbC5qcGciLCJlZGl0cyI6eyJyZXNpemUiOnsid2lkdGgiOjk1MCwiZml0IjoiY292ZXIifX19" style="width: 100%px;" class="fr-fic fr-dib">An illustration of an imaging technique that allows researchers to watch how nanoparticles respond to changes in their environment in real time. The blue lines represent the beam of an electron microscope as it impacts gold nanoblocks suspended in liquid in a small sample holder device called a liquid flow cell. Image credit: Ella Maru Studio.In the study, the Indiana team first suspended nanoparticles, a class of materials smaller than the average bacteria cell, in tiny channels of liquid on a microfluidic flow cell. This type of device allowed the researchers to flush different kinds of fluid into the cell on the fly while they viewed the mixture under their electron microscope. The researchers learned that the instrument gave the nanoparticles—which normally are attracted to each other—just enough electrostatic repulsion to push them apart and allow them to assemble into ordered arrangements.The nanoparticles, which are cubes made of gold, either perfectly aligned their faces in a tidy cluster or formed a more messy arrangement. The final arrangement of the material depended on the properties of the liquid the blocks were suspended in, and flushing new liquids into the flow cell caused the nanoblocks to switch between the two arrangements.The experiment was a proof of concept for how to steer nanoparticles into desired structures. Nanoparticles are too small to manually manipulate, but the approach could help engineers learn to reconfigure other nanoparticles by changing their environment.“You might have been able to move the particles into new liquids before, but you wouldn’t have been able to watch how they respond to their new environment in real-time,” said <a href="https://www.chem.indiana.edu/faculty/xingchen-ye/" target="_blank">Xingchen Ye</a>, IU associate professor of chemistry who developed the experimental technique and is the study’s lead corresponding author.“We can use this tool to image many types of nanoscale objects, like chains of molecules, viruses, lipids and composite particles. Pharmaceutical companies could use this technique to learn how viruses interact with cells in different conditions, which could impact drug development.”<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1725321753505-ezgif-6-b9c5db5d11.gif" style="width: 100%px;" class="fr-fic fr-dib">A view through an electron microscope of gold nanoparticles reconfiguring themselves in response to researchers changing the liquid the gold nanoparticles are suspended in—either butanol or a mix of octane and butanol. The black and white image on the left is unedited. At right, the gold nanoparticles are color-coded by their orientation. Initially floating in butanol, they’re arranged in a skewed crystal with more unfilled space in its center. Green and orange particles are mixed with blue particles. After researchers change the liquid to a mixture of butanol and octane, the squares’ faces align more closely together and more of the squares in the center of the crystal turn blue and green, representing a more ordered arrangement. Animation credit: Tobias Dwyer, Glotzer Lab, University of Michigan.An electron microscope isn’t necessary to activate the particles in practical morphable materials, the researchers said. Changes in light and pH could also serve that purpose.But to extend the technique to different kinds of nanoparticles, the researchers will need to know how to change their liquids and microscope settings to arrange the particles. Computer simulations run by the U-M team open the door to that future work by identifying the forces that caused the particles to interact and assemble.“We think we now have a good enough understanding of all the physics at play to predict what would happen if we use particles of a different shape or material,” said&nbsp;<a href="https://che.engin.umich.edu/people/moore-timothy/" target="_blank" rel="noreferrer noopener">Tim Moore</a>, U-M assistant research scientist of chemical engineering and co-first author of the study. He designed the computer simulations together with Dwyer and&nbsp;<a href="https://che.engin.umich.edu/people/glotzer-sharon/" target="_blank" rel="noreferrer noopener">Sharon Glotzer</a>, the Anthony C. Lembke Department Chair of Chemical Engineering at U-M and a corresponding author of the study.“The combination of experiments and simulations is exciting because we now have a platform to design, predict, make and observe in real time new, morphable materials together with our IU partners,” said Glotzer, who is also the John Werner Cahn Distinguished University Professor and Stuart W. Churchill Collegiate Professor of Chemical Engineering.

It’s a step toward smart coatings that change color—or other properties—on the fly.

Morphable materials: Researchers coax nanoparticles to reconfigure themselves

This article will guide you through the key features, functions, and configurations of the ESP8266 Pinout, setting the foundation for successful IoT implementations.

ESP8266 Pinout: Unlocking the Power of IoT's Favorite Microcontroller

Energy demands are at an all-time high, as is the need to be environmentally conscious. That’s why chemical engineering professors Drs. Joseph Kwon and Mark Barteau have developed a strategy to predict the performance of new catalysts for greener ammonia production. &nbsp;“By making industrial processes like ammonia production more sustainable, this research contributes to broader efforts to combat climate change, promoting a healthier planet for future generations,” Kwon said.&nbsp;Changing how ammonia is produced has environmental and economic benefits and enhances food security. This can be achieved by lowering the energy requirements and carbon emissions associated with traditional ammonia production.&nbsp;It is estimated that 1 to 2% of global energy consumption, and a similar fraction of man-made greenhouse gas (GHG) emissions, are associated with the production of ammonia for fertilizer.&nbsp;Ammonia is produced by the Haber-Bosch process, a century-old technology that uses atmospheric nitrogen and hydrogen to produce ammonia. The hydrogen is typically generated from methane via a process that generates a large GHG footprint.According to Kwon and Barteau, their research focuses on a greener alternative to the Haber-Bosch process. They are developing electrocatalysts for the electrochemical nitrogen reduction reaction, called NRR, using the hydrogen atoms in water.“The goal is to understand and enhance the interaction of nitrogen and hydrogen on the catalyst surface to efficiently produce ammonia at lower temperatures and pressures,” Kwon said. “To make these catalysts work as we hope, we computationally analyze various materials and their properties to predict which will perform best under NRR conditions.” &nbsp;<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1725000282502-News-CHEN-AmmoniaParticles-13August2024.jpg" style="width: 100%px;" class="fr-fic fr-dib">Nitrogen and Hydrogen produce ammonia in a procedure called the Haber-Bosch process, which creates a large GHG footprint. | Image:&nbsp;<cite id="isPasted">Texas A&amp;M Engineering</cite>Kwon and Barteau’s team combines the computational methods of density functional theory (DFT) and kinetic Monte Carlo (kMC) simulations to predict the efficiency and the stability of catalysts under electrochemical reaction conditions.Density functional theory is a modeling method that uses physics, chemistry and materials science to investigate the electronic structure of atoms and molecules. This method allows Kwon to predict how different materials will interact with nitrogen and hydrogen molecules.“Computational tools like DFT and kMC have revolutionized catalyst design in the 21st century,” said Barteau, one of the early practitioners applying DFT to heterogeneous catalysts. “What is particularly powerful about the combination of these tools is the ability to predict the dynamic performance of active materials under different conditions and over time.Kinetic Monte Carlo simulations use probability estimates to predict possible outcomes for an uncertain event. This will help researchers understand how the reactions evolve at different temperatures and pressures, providing insights into the scalability and lifetime of potential catalysts.&nbsp;“We aim to explore new electrocatalyst materials,” Kwon said. “However, employing each method independently can limit the scope of properties regarding materials and reaction processes. This approach allows us to systematically optimize the catalysts before they are even tested in a laboratory, streamlining the development process and paving the way for more sustainable fertilizer production methods.”&nbsp;Kwon also hopes that this research can lead to breakthroughs in catalyst design and a greater understanding of their function at the molecular level. &nbsp;Several key areas that the research focuses on are reducing environmental impact, advancing green chemistry, promoting energy security and catalyzing technological innovation. &nbsp;“This integrated approach not only accelerates the discovery of viable catalysts but also provides a comprehensive understanding of their behavior in real-world conditions, setting the stage for experimental validation and eventual industrial application,” Kwon said.

Drs. Joseph Kwon and Mark Barteau have discovered a way to produce ammonia for fertilizer that is greener and more efficient.

Greener Pastures: Better Ammonia Production for a More Sustainable Future

Soft polymers with the combined properties of electrolytes and traditional polymers offer some unique and desirable properties that can be drastically changed on demand. These gels, called metallo-polyelectrolyte complexes (MPECs, pronounced "EM-pecks"), can be stimulated externally by magnetic, electrochemical, and optical stimuli, making them ideal for some energy devices, responsive actuators, and nanofiltration systems. Metal ions within their cores provide the materials with these unique capabilities and form dynamic, "reversible" ionic bonds with polymer chains rather than much harder to break covalent bonds.While scientists had previously identified and, in some cases, synthesized, MPECs that demonstrate unusual material properties, which vary, for example, with the pH of the solution before they form into gels, the exact source of those unusual mechanical properties had remained a mystery. In addition, earlier fabrication techniques often were not easily scaled and suffered from uneven composition.Now, through a combination of extensive laboratory experiments, computational theoretical work, and additive manufacturing, a team of Caltech scientists has developed a complete framework for understanding a class of MPECs from the level of molecular bonds up to that of material properties. As a result, the work, reported in <a href="https://www.nature.com/articles/s41467-024-50860-6#Ack1" target="_blank">a paper</a> in the journal Nature Communications, provides a road map of sorts for designing and tailor-making gels with desired functionality and mechanical properties."Our lab typically works on interesting materials, which respond to external stimuli because of the way we build them into specific micro- or nano-architectures. What's so interesting and exciting about MPECs is that they can be actuated even without that kind of architecture," says <a href="https://www.eas.caltech.edu/people/jrgreer?back_url=%2Fpeople" target="_blank">Julia R. Greer</a>, the Ruben F. and Donna Mettler Professor of Materials Science, Mechanics and Medical Engineering; and the Fletcher Jones Foundation Director of the <a href="https://kni.caltech.edu/" target="_blank">Kavli Nanoscience Institute</a> at Caltech. She explains that these materials can exhibit vastly different properties and responses. For example, by choice of metal ion and pH, a sample can be made that bends to the left or to the right depending on how fast a force is applied to it. In another case, a sample can fully dissolve in water or remain solid for several days, with the only difference being the metal's ionic charge."This opens the door for 'training' an entire suite of new materials—both computationally and experimentally—that can enable previously challenging technologies, from self-monitoring autonomous filters to advanced ion-exchange membranes and catalysts, and even artificial muscles," Greer says."We were really focused on making a bridge between the molecular level interactions to the mechanical properties on a global scale, providing insight into phenomena that we can't necessarily see," says Seola Lee, co-lead author of a new paper about the work and a PhD student in mechanical engineering in the Greer lab who is currently a research scientist intern at Meta. "We hope that the guidelines we've demonstrated with will help people tap into the design territory in terms of what they will be able to make with these materials."Central to the changeability of MPECs are the metal ions at their cores and the connections they make to charged polymer chains. Many transition metals are multivalent, meaning they can have more than one possible charge. Valency is determined by an atom's outer shell of electrons. Iron, for example, can be present as Fe2+, a form in which it would likely attach to two polymer chains, or Fe3+, which would be more likely to bind with three chains.The Caltech team determined that the metal ions' valency is one of several levers that can be adjusted to tune the properties of MPECs, with the others being pH of the solution and the solvent used.For their investigation, the group used a process called stereolithography, a type of 3D printing where a light-induced polymerization creates a solid structure layer by layer. Carrying out this printing process with a resin that includes various metal ions, it is possible to print out a stable polymer called polyacrylic acid (PAA) with these metal ions bound to it. Next, they conducted exhaustive thermal and mechanical experiments on those materials to probe the material responses at different length scales. Pierre Walker, co-lead author of the paper and a graduate student in chemical engineering in the lab of&nbsp;<a href="https://cce.caltech.edu/people/zhen-gang-wang?back_url=%2Fpeople" target="_blank">Zhen-Gang Wang</a>, the Dick and Barbara Dickinson Professor of Chemical Engineering, analyzed the data and calculated how to model the details from the molecular level up to the full material scale."A lot of this investigation was kind of like walking around in the dark, where there were many different levers that at the time we had no idea were present," Walker says. "Other papers have looked at one or two effects at most in their study. The fact that we were able to couple all three, and the fact that we are able to not only understand how each of them interacts with each other, but how they then impact the global property really makes it much easier for future users of MPEC gels to navigate the space."In the new paper, the authors describe a few examples of MPECs they were able to design using their new framework. One, a shape-memory polymer, looks like a yellow gummy flower that has bloomed and is lying flat. After heating the flower to 90 degrees Celsius, Lee manually lifted the petals, closing the flower into a bud shape. She then cooled the whole thing to -5 degrees C. When she brought the temperature back to 90 degrees C, the flower bloomed and returned to its original shape. Here, the valency of the metal dictated how well the material "remembered" its original shape. The gel made with aluminum (Al3+) returned to the open flower position much more quickly and completely than either calcium (Ca2+) or sodium (Na+).In a second example, the scientists made a gel strip where one side was fabricated with a high pH and the other with a lower pH. Based on the theoretical modeling, the scientists knew how the two sides should behave when submerged in different solutions. And just as expected, when the bilayer was submerged in water, it buckled to the left; when in an aluminum solution, it buckled to the right."We now have a really robust explanation for if you change some of these small molecular levers, here's what comes out at the global scale," says Seneca Velling, a former graduate student in the Greer group who is now completing his studies in the Origins and Habitability Lab at JPL, which Caltech manages for NASA. "Therefore, if you want a global scale property, you can back it out by thinking about what starting conditions make that global property a reality, which is a really cool way to design a material. You can now explain it top-down or bottom-up."Additional authors of the new paper, titled "<a href="https://www.nature.com/articles/s41467-024-50860-6" target="_blank">Molecular Control via Dynamic Bonding Enables Material Responsiveness in Additively Manufactured Metallo-Polyelectrolytes</a>," are Amylynn Chen (PhD '23), Zane W. Taylor (BS '22), Cyrus J.B.M Fiori, Vatsa Gandhi (PhD '23, and Zhen-Gang Wang. The work was supported by funding from the&nbsp;<a href="https://cast.caltech.edu/" target="_blank">Center for Autonomous Systems and Technologies</a> at Caltech, the Army Research Office's Institute for Collaborative Biotechnologies, and the Schwartz/Reisman Foundation's Schwartz/Reisman Collaborative Science Program. Wang receives funding from the Hong Kong Quantum AI Lab and AIRInnoHK of the Hong Kong government.

Soft polymers with the combined properties of electrolytes and traditional polymers offer some unique and desirable properties that can be drastically changed on demand.

Materials Scientists Develop Road Map for Designing Responsive Gels with Unusual Properties

Not only do we need to cut carbon emissions to curb climate change, but many scientists say we also need to capture excess CO2 from the air to prevent continued climate impacts. Currently, however, carbon removal tends to be costly, and polluters may lack incentives to clean up their emissions.One solution is to create useful products from captured CO2, thus increasing the value of drawing it out of the air. Stanford engineers are proposing a way to do just that.In two recent papers, published in the&nbsp;<a href="https://pubs.acs.org/doi/10.1021/jacs.4c03652" data-extlink="" target="_blank">Journal of the American Chemical Society</a>&nbsp;and <a href="https://onlinelibrary.wiley.com/doi/10.1002/anie.202406761" data-extlink="" target="_blank">Angewandte Chemie</a>, a team of Stanford researchers demonstrated that it’s possible not only to convert carbon dioxide to ethanol but also to do so with very few byproducts. Previous efforts have not been able to design a reaction converting the gas with such high selectivity.The researchers chose to focus on ethanol – the same stuff that’s in alcoholic beverages – because the chemical is useful for many industries such as fuels, polymers, and pharmaceuticals. But right now ethanol is mostly made from crops such as corn harvested from vast acres in regions like the Midwest – the process is both land and resource intensive.The researchers propose a win-win: taking captured carbon dioxide and making ethanol, which would further reduce emissions by replacing more energy-intensive ethanol sources. “If we are able to turn CO2 into valuable chemicals, we close the cycle,” said the lead author of the two papers, Chengshuang Zhou, recent PhD graduate in chemical engineering. “We have the opportunity of not producing more carbon, but instead circulating the carbon that is already out there.”<h2>Creating the catalyst</h2>To test this idea, the researchers needed to combine carbon dioxide with hydrogen. But you can’t just put the two gases in a cylinder and shake them to make ethanol, because the reaction isn’t favorable. So the team needed to find a catalyst that would provide an extra kick, moving the reaction in the desired direction.To do so, they first considered the molecular structure of ethanol. “How do we cut several bonds to reconstruct CO2 so that we can retroactively come up with ways to synthesize ethanol from CO2?” Zhou asked. “This reaction would necessarily involve not only hydrogenation, essentially adding hydrogen to CO2, but also coupling two carbon atoms into one single molecule.”He identified that an ideal catalyst must produce at least two fragments, one deeply hydrogenated like methane (-CH3) and one partially hydrogenated like methanol (-CH2OH), which can then come together to form ethanol. He scoured the scientific literature for elements that can both synthesize methanol and encourage hydrogenation, arriving at ruthenium and indium. “Ruthenium has been well documented to be a great catalyst for the CO2 hydrogenation reaction to produce methane,” he said, while “indium oxide-based catalysts have been documented to catalyze CO2 hydrogenation to methanol.” The perfect match.Using nanoscale design and synthesis, the researchers created a ruthenium-indium oxide (Ru/In2O3) catalyst and put it to the test. In a stainless steel tube, the team flowed carbon dioxide and hydrogen across a small scoop of the powdered catalyst, adding pressure and heat to speed the reaction, and analyzed the gases that came out the other end.<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1724891477747-schematic_0.jpg" style="width: 100%px;" class="fr-fic fr-dib">A ruthenium-indium oxide catalyst that selectively converts CO2 and H2 into ethanol. Ruthenium nanoparticles (blue) are promoted by the encapsulation of both indium oxide (green) and functional organic polymers (pink). | Chengshuang ZhouIn their initial run, they produced mostly methanol, a promising first step reported in the&nbsp;Journal of the American Chemical Society&nbsp;that provided clues to the catalyst’s function. Now that they had one of two components, they could tweak the catalyst’s structure to encourage more stability, and thus produce ethanol.After the changes, they ran the experiment again and found that the input gases converted to 70% ethanol and only carbon monoxide as a byproduct, a finding reported in&nbsp;Angewandte Chemie. “That’s the biggest discovery,” said&nbsp;<a href="https://profiles.stanford.edu/matteo-cargnello" data-extlink="" target="_blank">Matteo Cargnello</a>, senior author of the papers and an associate professor of chemical engineering. “There was a way to direct this reaction to make mostly ethanol rather than other products.”This high selectivity of conversion is important because separating out ethanol from a mixture would be more energy intensive, which would somewhat defeat the purpose of the research. “If you can selectively make a simple, single product, that will absolutely reduce emissions,” said Cargnello.<h2>Scaling up to smokestacks</h2>While the team performed the experiment in a small tube, they believe the process could scale to settings like industrial chimneys. Before this work, “there hasn’t been a concise guiding principle” for converting carbon dioxide to ethanol, said Zhou. By demonstrating the potential to produce a high rate of ethanol, he believes the work sets the stage for future efforts to use metals that are more abundant. Ruthenium and indium are scarce metals, and using them for mass production of a catalyst would be costly.That’s Cargnello’s next step. He will work with elements in the first row of transition metals on the periodic table, which are far more common and therefore cheaper to scale. He plans to develop a catalyst that can be widely used in conjunction with various sources of carbon dioxide – including captured from the air or from a smokestack – to turn the gas into ethanol, which can then be bottled and sold.“Our hypothesis is that we can make it work with cheaper metals and then be able to scale it up,” Cargnello said. “Because we certainly want our discovery to not just be an academic discovery, we would like it to be translated into a larger scale process.”Cargnello is also a member of&nbsp;<a href="https://biox.stanford.edu/" data-extlink="" target="_blank">Stanford Bio-X</a>.Additional Stanford co-authors of the papers include graduate students Gennaro Liccardo, Jinwon Oh, and Sindhu Nathan; and postdoctoral researchers Michael Stone, Eric J. McShane, and Baraa Werghi.&nbsp;Other co-authors include researchers at the California Institute of Technology, SLAC National Accelerator Laboratory, and Lawrence Berkeley National Lab.&nbsp;

Researchers demonstrated that it’s possible not only to convert carbon dioxide to ethanol but also to do so with very few byproducts. | iStock/onurdongel

Stanford scientists designed a catalyst that turns carbon dioxide into ethanol, which could incentivize cleaning up emissions.

Turning carbon pollution into ethanol

Acrylonitrile Styrene Acrylate (ASA) filament has emerged as a popular choice in 3D printing, particularly for applications demanding both durability and resilience. As a copolymer, ASA combines the properties of acrylonitrile, styrene, and acrylate, resulting in a material that offers superior performance in challenging environments. One of the critical factors influencing ASA’s usability is its glass transition temperature (Tg), which plays a pivotal role in determining the filament's suitability for various applications.The ASA glass transition temperature, typically about 100°C depending on the material and testing process, is a measure of the temperature at which the polymer transitions from a rigid, glassy state to a more flexible, rubbery state.[1] This property is crucial for assessing the material’s thermal stability and its ability to maintain structural integrity under heat. A high Tg indicates that ASA can withstand elevated temperatures without significant deformation, making it an ideal choice for parts exposed to heat or thermal cycles.Additionally, the ASA glass transition temperature affects its performance in outdoor and high-stress environments. The ability of ASA to retain its mechanical properties and resist deformation at elevated temperatures contributes to its suitability for a range of applications, from automotive components to outdoor equipment.[2] This article goes over the basics of ASA glass transition temperature and its relevance to 3D printing.<h2 dir="ltr">What is ASA 3D Printing Filament?</h2><img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1724850853776-3d_printed_gears.jpg" style="width: 100%px;" class="fr-fic fr-dib" alt="asa filament">ASA filament is comparable in performance to ABSAcrylonitrile Styrene Acrylate (ASA) is a widely used thermoplastic in FDM/FFF 3D printing, known for its excellent weather resistance, mechanical strength, and UV stability. Often compared to ABS (Acrylonitrile Butadiene Styrene), ASA offers similar strength and durability but with superior resistance to outdoor conditions, making it ideal for applications that require exposure to sunlight or harsh weather.ASA’s UV stability prevents yellowing and degradation, ensuring that parts maintain their color and structural integrity over time. This property makes it a popular choice for automotive components, outdoor fixtures, and any application where prolonged exposure to the elements is a concern. Additionally, ASA is resistant to chemicals and has good impact strength, making it suitable for functional prototypes and end-use parts.In terms of printability, ASA is less prone to warping compared to ABS, although it still requires a heated bed and an enclosed build chamber for optimal results. Its slightly lower shrinkage reduces the risk of warping, but careful attention to bed adhesion and temperature control is necessary to minimize these issues. ASA typically prints at temperatures between 240°C and 260°C, with a heated bed set around 90°C to 110°C. The use of an enclosure helps maintain consistent temperature, reducing the likelihood of warping and cracking.ASA also supports post-processing, such as sanding, painting, and vapor smoothing, allowing for aesthetically pleasing and functional final products. However, one drawback is the emission of fumes during printing, similar to ABS, which requires adequate ventilation.Recommended reading: <a href="https://www.wevolver.com/article/asa-vs-abs" target="_blank">ASA vs ABS: Finding the right 3D printing filament</a><h2 dir="ltr">ASA Glass Transition Temperature</h2>The glass transition temperature (Tg) of Acrylonitrile Styrene Acrylate (ASA) is around 100°C, depending on the material and the testing process. This is a fairly high glass transition temperature compared to other low-cost 3D printing thermoplastics (but low compared to engineering plastics), making ASA particularly suitable for prototyping and low-risk applications where heat resistance and structural integrity are important.For comparison, ABS, a close relative of ASA, has a Tg of about 105°C, slightly higher than ASA. Both materials behave similarly during printing, requiring heated beds and enclosed chambers to maintain temperatures above their Tg to ensure proper layer adhesion. However, ASA offers better UV and weather resistance, making it the preferred choice for outdoor applications.On the other hand, PLA (Polylactic Acid), another widely used 3D printing material, has a much lower Tg of around 60°C. While PLA is easier to print due to its lower temperature requirements and minimal warping, its lower Tg limits its use in environments where higher temperatures are present. PLA parts can deform or soften under moderate heat, making them unsuitable for outdoor or high-heat applications where ASA would excel.Comparatively, materials like PETG (Polyethylene Terephthalate Glycol) have a Tg around 80°C. PETG offers a good balance between ease of printing and heat resistance but lacks the UV stability of ASA, making ASA a better choice for outdoor parts that must endure sunlight and heat without degrading.ASA’s Tg ensures that printed parts remain structurally stable and retain their mechanical properties in environments that would challenge lower Tg materials. However, designers must still consider ASA's limitations, ensuring that printed parts do not operate in conditions where temperatures exceed 100°C, as this could lead to softening and loss of strength.<h2 dir="ltr">Why Does ASA Glass Transition Temperature Vary?</h2>The glass transition temperature (Tg) of ASA (Acrylonitrile Styrene Acrylate) can vary due to several factors related to its composition and processing conditions. ASA is a copolymer, meaning it is made from multiple monomers—acrylonitrile, styrene, and acrylate.[3] The ratios of these monomers can affect the Tg. Variations in the proportions can lead to differences in the polymer's rigidity and thermal properties.Additionally, the presence of additives or fillers can influence the Tg. These can include impact modifiers, stabilizers, or colorants, each of which can alter the polymer’s thermal behavior. The manufacturing process also plays a crucial role; factors such as polymerization conditions, cooling rates, and thermal history can impact the final Tg. Variability in these conditions can result in slight changes in the Tg from one batch of ASA to another.Finally, the Tg can be affected by the molecular weight of the polymer chains. Higher molecular weight ASA may exhibit a different Tg compared to lower molecular weight variants due to differences in chain entanglement and mobility. Thus, the glass transition temperature of ASA is not fixed but rather a range influenced by its specific formulation and processing history.<h2 dir="ltr">Thermal Properties of Different ASA Filament Brands</h2><img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNzI0Njk2ODI3Mjk0LVAxNTMzMDk0LTEwMjR4NTc3LmpwZyIsImVkaXRzIjp7InJlc2l6ZSI6eyJ3aWR0aCI6OTUwLCJmaXQiOiJjb3ZlciJ9fX0=" style="width: 100%px;" class="fr-fic fr-dib" alt="prusament">Part made with Prusament ASA material (image credit:&nbsp;<a href="https://prusament.com/materials/prusament-asa/" target="_blank" rel="noopener noreferrer">Prusament</a>)&nbsp;When 3D printing ASA filament, the ASA glass transition temperature is not necessarily the main property to focus on. This is due to a number of factors, but mainly because the extrusion temperature of a material is closer to its melting point than its glass transition temperature.All filament manufacturers offer recommended printing temperatures for their ASA filament, as well as recommended bed temperatures. But many do not specify the glass transition temperature of the product, as it is less relevant for its end use. The table below shows the slight variations in ASA print settings between filament brands.<div dir="ltr" align="left"><table><tbody><tr><td>Brand</td><td>Glass Transition Temperature</td><td>Recommended Printing Temperature</td><td>Recommended Bed Temperature</td></tr><tr><td>Prusament ASA</td><td>Not specified</td><td>255°C - 265°C</td><td>105°C - 115°C</td></tr><tr><td>FormFutura ApolloX</td><td>98°C</td><td>235°C - 255°C</td><td>80°C - 100°C</td></tr><tr><td>Filamentum ASA extrafill</td><td>Not specified</td><td>240°C - 255°C</td><td>80°C - 105°C</td></tr><tr><td>Polymaker PolyLite ASA</td><td>97.8°C</td><td>240°C - 260°C</td><td>75°C - 95°C</td></tr><tr><td>eSun ASA</td><td>Not specified</td><td>240°C - 270°C</td><td>90°C - 110°C</td></tr></tbody></table></div><h2 dir="ltr">High-Temperature Performance of 3D Printed ASA</h2>3D printed ASA (Acrylonitrile Styrene Acrylate) is known for its good temperature resistance and UV resistance for its price point, making it a preferred material for outdoor and high-temperature applications. This property is also particularly advantageous for parts that undergo thermal cycling.In terms of UV resistance, ASA excels compared to other common 3D printing materials like ABS. ASA’s chemical composition includes a high level of acrylate, which provides better protection against UV degradation. This makes ASA highly resistant to yellowing and physical degradation when exposed to sunlight, ensuring that printed parts retain their mechanical properties and aesthetic appearance over time. The inherent UV stability of ASA is beneficial for outdoor applications, such as automotive parts, construction components, and various outdoor equipment.To enhance the heat resistance of ASA 3D prints, consider the following strategies:<h3 dir="ltr">Optimize Print Settings</h3>Increase the extrusion temperature and print bed temperature to ensure better layer adhesion and reduce internal stresses. A higher nozzle temperature (typically between 240°C and 260°C) ensures the material is fully fused, leading to stronger, more heat-resistant prints. Slower print speeds can also improve inter-layer bonding, contributing to overall thermal stability.<h3 dir="ltr">Annealing</h3>Post-process the ASA print by annealing it in an oven. Heating the print to a temperature just below the glass transition temperature (around 85°C to 95°C) for a few hours can relieve internal stresses and improve the crystallinity of the polymer. This process can enhance the print’s thermal resistance and dimensional stability when exposed to higher temperatures.<h3 dir="ltr">Infill and Wall Thickness Adjustment</h3>Increase the infill percentage and wall thickness to reinforce the print. A denser infill and thicker walls create a more robust structure that can better resist deformation under heat. Additionally, using a higher number of perimeters can enhance the print’s rigidity, making it less susceptible to warping or softening when exposed to elevated temperatures.Recommended reading: <a href="https://www.wevolver.com/article/what-is-pla-filament-composition-advantages-applications" target="_blank">What is PLA Filament? Composition, Advantages, Applications</a><h1 dir="ltr">Conclusion</h1><img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1724850879343-green_car_side_mirror.jpg" style="width: 100%px;" class="fr-fic fr-dib" alt="car">ASA's UV resistance makes it suitable for external car parts like mirror housingsASA's glass transition temperature (Tg) is an important parameter that influences its mechanical, thermal, and chemical properties. Understanding Tg is helpful for optimizing ASA's performance in diverse engineering applications, from automotive exteriors to electronic housings. However, ordinary 3D printer users should focus on a material’s suggested printing temperature rather than its glass transition temperature to achieve a high level of printing performance.<h1 dir="ltr">Frequently Asked Questions (FAQ)</h1>What is the ASA glass transition temperature?The glass transition temperature of ASA is around 100°C.What is the ideal printing temperature for ASA?ASA filament prints best at an extrusion temperature of around 250°C and a bed temperature of around 100°C.How does ASA compare to ABS?ASA has a slightly lower glass transition temperature than ABS. It is therefore fractionally less heat resistant but offers superior UV and water resistance.What are some popular ASA filaments?Common ASA filament brands include FormFuture ApolloX, Filamentum ASA extrafill, and Polymaker PolyLite ASA.<h1 dir="ltr">References</h1>[1] Shen MC, Eisenberg A. <a href="https://www.sciencedirect.com/science/article/abs/pii/0079678667900398" target="_blank">Glass transitions in polymers</a>. Rubber Chemistry and Technology. 1970 Jan 1;43(1):95-155.[2] Berzinis A, Andriuli M. <a href="https://www.sae.org/publications/technical-papers/content/1999-01-0847/" target="_blank">Weathering performance of black thermoplastic resins for unpainted automotive exterior applications</a>. SAE transactions. 1999 Jan 1:706-15.[3] Breulmann M. <a href="https://www.researchgate.net/publication/230137160_Synthesis_Properties_and_Applications_of_Acrylonitrile-Styrene-Acrylate_Polymers" target="_blank">Synthesis, Properties and Applications of Acrylonitrile±Styrene±Acrylate Polymers</a>. Modern Styrenic Polymers: Polystyrenes and Styrenic Copolymers. 2003 Mar 1:341.

The ASA glass transition temperature is around 100°C. This makes it slightly easier to print than ABS, while it is also better for outdoor applications due to its good UV resistance.

ASA Glass Transition Temperature & Its Impact on 3D Printing

Using a combination of machine learning and powerful X-rays, Cornell researchers have solved a mystery behind the unusual behavior seen in a class of materials with potential for thermoelectric energy conversion and other applications.Researchers have long shown that the cubic phase of germanium telluride (GeTe) exhibits an unexpected rise in lattice thermal conductivity as its temperature increases. But knowing that a property exists and explaining why it exists are two very different things.Zhiting Tian, associate professor at the Sibley School of Mechanical and Aerospace Engineering in Cornell Engineering, is the lead author of a new paper in&nbsp;<a href="https://doi.org/10.1038/s41467-024-51377-8" target="_blank">Nature Communications</a> that provides a convincing explanation for the unexpected behavior of GeTe. More generally, the research deepens researchers’ understanding of thermal transport in a class of materials known as phase-change materials.What Tian and her team of researchers found is that as a sample of GeTe is heated to the point where its phase changes from a rhombohedral structure to a cubic structure, the bonds between second-nearest neighbors of like atoms (Ge-Ge and Te-Te) strengthen considerably. Ge-Ge bond strength increased by 8.3% and the strength of Te-Te bonds increased by a remarkable 103% as the sample’s temperature rose from 693 degres Kelvin to 850 degrees Kelvin.The group used machine learning-assisted first-principles calculations corroborated by X-ray scattering measurements to computationally reproduce the increasing thermal conductivity trend for the first time. They then borrowed a commonly used chemistry technique to perform the bonding analysis, and confirmed that these increasingly strong second-nearest neighbor bonds play a major role in GeTe’s previously unexplained increase in lattice thermal conductivity.“Computationally, it was quite prohibitive to look at temperature effects and to consider higher-order scattering, for example,” Tian said. “But because we were able to leverage machine learning potential, we were able to more efficiently extract the interactions and consider the multiple effects – temperature dependence, four-phonon scattering, and coherence contribution – all at once.”Phase-change materials such as GeTe are valued for their usefulness in a range of optical and electronic applications. Their optical and electrical properties change markedly depending on which of several stable phase states they are in and these phase states can be easily reversed. Moreover, GeTe has been talked about as a replacement for the semiconductor lead telluride as a thermoelectric material, due to lead’s inherent toxicity, according to Tian, who is a faculty fellow at the Cornell Atkinson Center for Sustainability.The work demonstrates an efficient and thorough pathway toward accurate modeling of materials near phase transitions or at high temperatures that have promise for phase change, thermoelectric and other energy applications.“We also identified other materials which showed a similar increase in conductivity, including tin-telluride and tin-selenide,” Tian said. “And so we hope our work will spark interest in looking deeper into the thermal transport behavior of other phase-change materials.”The work was supported by Tian’s National Science Foundation CAREER Award.

Using a combination of machine learning and powerful X-rays, Cornell researchers have solved a mystery behind the unusual behavior seen in a class of materials with potential for thermoelectric energy conversion and other applications.

Machine learning explains material's thermal conductivity

Technician Testing Diode on Printing Circuit Board

This article delves into the intricacies of diode, anode, cathode, and polarity, exploring the fundamental principles that drive countless electronic devices and systems, shaping the technological landscape we navigate daily.

Diode, Anode, Cathode: Unlocking the Power of Semiconductor Junctions

“Nanomaterials” is a broad term used to describe chemical substances or materials in which a single unit is sized between 1 and 100 nanometers (a nanometer is a billionth of a meter). They include exotic materials such as carbon nanotubes, silver nanoparticles (used as antimicrobials), nanoporous materials, and many types of catalysts used for efficiently driving chemical reactions.Nanomaterials are currently used in a wide range of fields, from medicine to electronics, which means that the ability to determine their exact chemical composition is essential. Nonetheless, this proves challenging, because traditional methods for analyzing nanomaterials tend to be susceptible to low signal-to-noise ratios.For example, one extensively used method is energy-dispersive X-ray spectroscopy (EDX), combined with scanning transmission electron microscopy. This technique provides detailed maps of where different elements are located within a sample, but it often produces noisy data, especially on such small objects, and mixed signals when different materials overlap, making precise chemical analysis difficult.The noisy data are usually “cleaned up” with various techniques, from simple spatial filtering to more sophisticated machine learning approaches like principal component analysis, that separate the signals from the noise, but they too have their drawbacks. For example, they can introduce errors, or struggle to distinguish between chemical signals when they are very similar.Now, three scientists at EPFL, Hui Chen, Duncan Alexander, and Cécile Hébert have developed a machine learning-based method called PSNMF (“non-negative matrix factorization-based pan-sharpening”) that enhances the clarity and accuracy of EDX data, making it easier to identify and quantify different chemical elements in nanomaterials.The team started by leveraging a special characteristic of their data called “Poisson noise”. This type of noise occurs because the detection of X-ray photons is random. When the electron beam hits the sample, it produces X-ray photons, but the number detected varies randomly each time, creating a noisy, grainy pattern known as Poisson noise.To improve the clarity of their data, the researchers combined data from nearby pixels, enhancing the signal-to-noise ratio in the spectrum at the cost of the spatial resolution.They then applied a machine learning method called "non-negative matrix factorization" (NMF) to this clearer dataset. NMF is a mathematical technique that breaks down a large dataset into simpler, smaller parts, ensuring all parts are non-negative, which helps identify patterns in the data. This approach gave them good spectral data at the cost of having blurry images with large pixels.Next, they repeated the NMF process on the original high-resolution dataset to preserve detailed spatial information, but initializing the factorization with the previously identified spectral components. Finally, they combined the results from both steps to produce a high-quality dataset, that has both high spectral fidelity and high spatial resolution.The researchers validated PSNMF using synthetic data, computed thanks to a modelling algorithm developed in the lab. Those data mimicked real-world challenges, such as analyzing mineral samples formed under extreme conditions. The method proved highly effective, accurately identifying and separating different materials, even those in tiny amounts.When applied to actual samples, including a nanomineral and a nanocatalyst, PSNMF successfully separated and quantified overlapping materials. This precise analysis is crucial for understanding and developing new technologies that rely on these complex nanostructures.PSNMF is a significant improvement in nanoscale chemical analysis. By providing accurate results despite noisy data and overlapping signals, this method enhances our ability to study and utilize nanomaterials in various fields, from advanced electronics to medical devices.<hr>ReferencesHui Chen, Duncan T.L. Alexander, Cécile Hébert. Leveraging machine learning for advanced nanoscale X-ray analysis: Unmixing multicomponent signals and enhancing chemical quantification. NanoLetters 06 August 2024. DOI:&nbsp;<a href="https://doi.org/10.1021/acs.nanolett.4c02446" title="DOI URL" target="_blank" rel="noopener">10.1021/acs.nanolett.4c02446</a>

EPFL scientists have developed an AI-based technique to improve chemical analysis of nanomaterials, overcoming challenges of noisy data and mixed signals.

AI enhances chemical analysis at the nanoscale

Composite metal foam could make aircraft wings or armor simultaneously stronger and lighter. An advanced material, the properties of composite metal foam (CMF) indeed make it attractive for a wide range of applications.There’s a problem, though. To bring many of those applications to life, manufacturers must be able to weld CMF components together — without impairing the properties that make it so attractive.Researchers at NC&nbsp;State University might have found a solution. It’s called induction welding.“Most forms of traditional welding don’t work well with metal foams,” says Afsaneh Rabiei, a professor of mechanical and aerospace engineering at NC State and corresponding author of a <a href="https://onlinelibrary.wiley.com/doi/10.1002/adem.202301430" target="_blank">paper on the new research</a>.&nbsp;Induction welding, as the name implies, uses an induction coil to create an electromagnetic field that heats the metal. Rabiei and the research team published findings that indicate induction welding works very well on CMF components.<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1723586190704-CompositeMetalFoam-graphic.jpg" style="width: 100%px;" class="fr-fic fr-dib">A graphical illustration of induction welding being used on CMF components.Commonly made out of stainless steel or titanium, CMFs are foams that consist of hollow, metallic spheres. These pockets of air in CMFs make the material light, strong and effective at insulating against high temperatures.“Traditional fusion welding uses a filler to connect two pieces of metal,” Rabiei says. “This is problematic because the metal being melted to fuse two pieces of CMF is solid, so it lacks the desirable properties of the CMF on either side of it. In addition, any type of welding that uses direct heat to melt the metal results in some of the porosity in the CMF being filled in, which impairs its properties.”Rabiei says CMF is only 30-35% metal. So the electromagnetic field created by induction welding can “penetrate deeply into the material — allowing for a good weld.”&nbsp;Meanwhile, the air pockets that make up the remaining 65-70% “serve to insulate the material against the heat,” which allows a welder to heat a joint without the heat spreading too far.&nbsp;“That helps to preserve the CMF’s properties,” Rabiei says.Together with NC&nbsp;State Ph.D. students John Cance and Zubin Chacko, Rabiei&nbsp;<a href="https://news.ncsu.edu/2023/12/welding-metal-foam/" target="_blank">published “A Study on Welding of Porous Metals and Metallic Foams”</a> in the journal&nbsp;Advanced Engineering Materials&nbsp;late last year.This article is based on a&nbsp;<a href="https://news.ncsu.edu/2023/12/welding-metal-foam/" target="_blank">news release</a>&nbsp;from NC State University.

An F/A-18 Super Hornet fighter jet sits onboard an aircraft carrier deck sailing the ocean.

Composite metal foam could make aircraft wings or armor simultaneously stronger and lighter. An advanced material, the properties of composite metal foam (CMF) indeed make it attractive for a wide range of applications.

Welding Metal Foam

Electronic waste, or e-waste, is a rapidly growing global problem, and it’s expected to worsen with the production of new kinds of flexible electronics for robotics, wearable devices, health monitors, and other new applications, including single-use devices.A new kind of flexible substrate material developed at MIT, the University of Utah, and Meta has the potential to enable not only the recycling of materials and components at the end of a device’s useful life, but also the scalable manufacture of more complex multilayered circuits than existing substrates provide.The development of this new material is described this week in the journal&nbsp;RSC: Applied Polymers, in a&nbsp;<a href="http://doi.org/10.1039/D4LP00182F" target="_blank">paper</a> by MIT Professor Thomas J. Wallin, University of Utah Professor Chen Wang, and seven others.“We recognize that electronic waste is an ongoing global crisis that’s only going to get worse as we continue to build more devices for the internet of things, and as the rest of the world develops,” says Wallin, an assistant professor in MIT’s Department of Materials Science and Engineering. To date, much academic research on this front has aimed at developing alternatives to conventional substrates for flexible electronics, which primarily use a polymer called Kapton, a trade name for polyimide.Most such research has focused on entirely different polymer materials, but “that really ignores the commercial side of it, as to why people chose the materials they did to begin with,” Wallin says. Kapton has many advantages, including excellent thermal and insulating properties and ready availability of source materials.The polyimide business is projected to be a $4 billion global market by 2030. “It’s everywhere, in every electronic device basically,” including parts such as the flexible cables that interconnect different components inside your cellphone or laptop, Wang explains. It’s also widely used in aerospace applications because of its high heat tolerance. “It’s a classic material, but it has not been updated for three or four decades,” he says.However, it’s also virtually impossible to melt or dissolve Kapton, so it can’t be reprocessed. The same properties also make it harder to manufacture the circuits into advanced architectures, such as multilayered electronics. The traditional way of making Kapton involves heating the material to anywhere from 200 to 300 degrees Celsius. “It’s a rather slow process. It takes hours,” Wang says.The alternative material that the team developed, which is itself a form of polyimide and therefore should be easily compatible with existing manufacturing infrastructure, is a light-cured polymer similar to those now used by dentists to create tough, durable fillings that cure in a few seconds with ultraviolet light. Not only is this method of hardening the material comparatively fast, it can operate at room temperature.The new material could serve as the substrate for multilayered circuits, which provides a way of greatly increasing the number of components that can be packed into a small form factor. Previously, since the Kapton substrate doesn’t melt easily, the layers had to be glued together, which adds steps and costs to the process. The fact that the new material can be processed at low-temperature while also hardening very quickly on demand could open up possibilities for new multilayer devices, Wang says.As for recyclability, the team introduced subunits into the polymer backbone that can be rapidly dissolved away by an alcohol and catalyst solution. Then, precious metals used in the circuits, as well as entire microchips, can be recovered from the solution and reused for new devices.“We designed the polymer with ester groups in the backbone,” unlike traditional Kapton, Wang explains. These ester groups can be easily broken apart by a fairly mild solution that removes the substrate while leaving the rest of the device unharmed. Wang notes that the University of Utah team has co-founded a company to commercialize the technology.&nbsp;“We break the polymer back into its original small molecules. Then we can collect the expensive electronic components and reuse them,” Wallin adds. “We all know about the supply chain shortage with chips and some materials. The rare earth minerals that are in those components are highly valuable. And so we think that there’s a huge economic incentive now, as well as an environmental one, to make these processes for the recapture of these components.”The research team included Caleb Reese and Grant Musgrave at the University of Utah, and Jenn Wong, Wenyang Pan, John Uehlin, Mason Zadan and Omar Awartani at Meta’s Reality Labs in Redmond, Washington. The work was supported by a startup fund at the Price College of Engineering at the University of Utah.

A new kind of flexible substrate material developed at MIT, the University of Utah, and Meta could help combat e-waste. Credit: Christine Daniloff, MIT; iStock

Electronic waste is a rapidly growing problem, but this degradable material could allow the recycling of parts from many single-use and wearable devices.

New substrate material for flexible electronics could help combat e-waste

<h2 id="isPasted">Programmable Logic Controller (PLC)</h2>A PLC is designed to control part or all of a manufacturing process and is simple to use and set up, even for entry-level programmers. A PLC can diagnose faults quickly, and its modular design allows for tailor-made systems to suit every application. A PLC is a highly reliable industrial computer constructed from high-grade, durable materials that can withstand a range of environmental pressures. Its real-time response to changing conditions means operations continue uninterrupted, even when a fault is being resolved.<h2>Human Machine Interface (HMI)</h2>An HMI is what enables human interaction with the machines that are doing the work, and usually consists of a panel interface that may have keypads, displays and USB connections. While human beings control and operate the machine via the HMI, the machine closely monitors production and simultaneously feeds back information to the operator. This allows quicker and more accurate decision-making and a rapid response to constantly changing production demands.<h2>Distributed Control System (DCS)</h2>A Distributed Control System is one where a network of autonomous machine controllers is centrally governed by a supervisory operator. Various nodes and control processors are placed at strategic points throughout the manufacturing system, where they can assist in batch-orientated or continuous processes. This means that any problems in the system are localised and only affect that part of the manufacturing process directly controlled by the node, thus reducing overall production downtime.<h2>Supervisory Control and Data Acquisition (SCADA)</h2>SCADA is a more complex automation concept, referring to a control system architecture which provides an advanced level of supervisory plant management. This architecture comprises a whole network of computers, in one or more locations, combined with a user interface and high speed data communications which allow a distributed network to be accessed remotely.<h2>Artificial Neural Network (ANN)</h2>An ANN is the basis of Artificial Intelligence and is effectively a computer model based on a biological brain. The brain's neural structure comprises a network of interconnected sensors and synapses, which receive and transmit information to a biological creature and control its responses to received sensory data. The big advantage of a neural network is that it learns by processing and adapting both internal and external information, and an ANN does this in the same way as a biological one. ANNs process data sets and learn from the information there so that they can respond to problems and produce solutions from their own computational capacity.

Automation concepts cover a range of increasingly complex machine initiatives that enhance all areas of 21st century life, and are especially useful for streamlining commercial and production processes.

Five Key Concepts in Automation

What is PLA filament and why is it so popular for entry-level 3D printing and beyond? This article covers the basics of Polylactic Acid.

What is PLA Filament? Composition, Advantages, Applications

Manufacturing cars with strong, lightweight aluminum alloys rather than steel could improve fuel efficiency and extend electric vehicle range, but the material’s instability at high temperatures has held the alloys back from widespread adoption.Creating tiny, reinforcing particles of titanium carbide (TiC) directly inside of molten aluminum results in a stronger, more temperature resistant aluminum-based material called a metal matrix nanocomposite.Up to this point, researchers have not understood how these nanoparticles form, or how they interact with other features in the microstructure, hindering production of the material on an industrial scale.University of Michigan researchers have used a unique high-resolution, 3D x-ray technique to provide a first glimpse into how nanoparticles form, where they are located and how they facilitate further solidification of the molten metal. A paper on the work will be published in the September edition of Acta Materialia.“Most metals start their lifetimes in the liquid state. How they convert from liquid to solid will ultimately determine their microstructures, and hence, their properties and applications,” said <a href="https://mse.engin.umich.edu/people/shahani" target="_blank" rel="noreferrer noopener">Ashwin Shahani</a>, an associate professor of materials science and engineering and chemical engineering at U-M and co-corresponding author of the study.“The study enabled us to understand exactly how the nanoparticles interact with secondary phases in casting, which has been a major challenge for the past half-century.”&nbsp;As nanoparticles are less than 100 nanometers, one ten-thousandth of a millimeter, the researchers used a powerful imaging technique called synchrotron-based x-ray nanotomography to visualize metal microstructure nondestructively in 3D—a feat not possible with conventional imaging approaches.To obtain the visualizations, the researchers created an aluminum composite reinforced with titanium carbide (TiC). That involved a flux-assisted reaction in which a mixture of carbon powder and titanium-bearing salt was reacted with an aluminum melt. 3D reconstructions revealed an unexpected diversity of titanium aluminide (Al3Ti) intermetallic structures, including one that formed directly on TiC nanoparticles larger than 200 nm in diameter. In that case, the Al3Ti crystals grew into an unusual orthogonal plate structure. Meanwhile, the TiC nanoparticles smaller than the 200 nanometer threshold split the Al3Ti intermetallic plates during solidification, forming branched structures.<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1722783000473-ezgif-6-9087a81780.gif" style="width: 100%px;" class="fr-fic fr-dib">A magnified view of the “orthogonal plates” of Al3Ti that nucleated on a TiC nanoparticle. The structure measures 10 μm along its longest dimension. Credit: Ashwin Shahani, Michigan Engineering.In addition to imaging, the researchers used phase-field simulations to fill in spatiotemporal “gaps” in the experiments and propose a mechanism for microstructure formation.“We now have evidence that the nanoparticles form well before the intermetallics, and not the other way around, which has important implications regarding the nucleation of the nanoparticles in the first place,” said Shahani.With these results in hand, industry partners can now guide TiC and Al3Ti formation when manufacturing aluminum composites on a large scale—adjusting solidification pathways or alloy chemistries to achieve the desired microstructure and its associated properties.“We have known for a long time that nano-sized particles could improve the performance of metal matrix composites, but the materials could not be produced at scale. We now understand the formation mechanisms that will enable our industry partners to optimize the process for lightweighting applications,” said Alan Taub, a Robert H. Lurie Professor of Engineering and director of the Electric Vehicle Center at U-M and co-corresponding author of the study.Taub is also a professor of materials science and engineering, mechanical engineering and macromolecular science and engineering.This research was funded by the National Science Foundation (grant no. 1762657).Synchrotron-based x-ray nanotomography was performed at the National Synchrotron Light Source II at Brookhaven National Laboratory. Further characterization was done at the Michigan Center for Materials Characterization. &nbsp;&nbsp;

The lightweight material could extend EV range or fuel efficiency once its microstructure is understood.

First 3D visualization of an aluminum nanocomposite for the auto industry

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materials

PLA, ABS, and PETG are three of the most popular filaments for FDM 3D printing.

In this article, we look at how three of the most commonly used filaments—PLA, ABS, and PETG—compare in terms of printability, properties, and availability.

PLA vs ABS vs PETG: A Comparison of 3D Printing Filaments

Thermoplastic filament is just one type of 3D printing material

From low-cost plastic filament to engineering-grade titanium powder, the range of available 3D printing materials is wider than ever. Here we look at the key material categories.

Types of 3D Printing Materials and How They Form Backbone of Additive Manufacturing

materials

Profiles