The EPMA is hosting a webinar covering the possibility of producing metal powder at low orbit with low or reduced gravity.
‘With the increased activity of space agencies and even private companies in space, there is a growing number of examples of successful research carried out in microgravity conditions in order to improve industrial processes at ground level,’ the organisation said. ‘In the past, powder metallurgy experiments have been carried out, for instance, on board of the International Space Station.’
The webinar will feature a presentation from US company Space Commerce Matters (SCM) about conducting technology experiments in low orbit flights.
The deadline for registration is 25 January 2021. To register, go here and for more information go here.
This story uses material from the EPMA, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier.
A new supply chain management consultancy has been launched in the UK focusing on SMEs in the automotive, aerospace and defense sectors.
According to Develop and Supply In-Sync (DASIS), the company covers aspects of the product manufacturing process from concept to completion for sectors such as CNC machining, composites, additive manufacturing (AM), technical products, engineering services and consumable products.
‘Together with our consortium of trusted partners, we offer businesses a unified and bespoke service that ensures on time delivery of first-class products and components,’ said Ian Wilson, CEO of DASIS. ‘Our extensive knowledge of program management, combined with hands on manufacturing experience, has allowed us to fulfil a dream of synchronising supply chain activity.’
This story uses material from DASIS, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier.
Engineering researchers have developed a new technique for eliminating particularly tough blood clots, by using engineered nanodroplets and an ultrasound 'drill' to break up the clots from the inside out. The technique has not yet gone through clinical testing, but in vitro testing has shown promising results.
Specifically, the new approach is designed to treat retracted blood clots, which form over extended periods of time and are especially dense. These clots are particularly difficult to treat because they are less porous than other clots, making it hard for drugs that dissolve blood clots to penetrate into the clot.
The new technique has two key components: the nanodroplets and the ultrasound drill. The nanodroplets consist of tiny lipid spheres that are filled with liquid perfluorocarbons (PFCs). Specifically, the nanodroplets are filled with low-boiling-point PFCs, which means that a small amount of ultrasound energy will cause the liquid to convert into gas. As they convert into a gas, the PFCs expand rapidly, vaporizing the nanodroplets and forming microscopic bubbles.
"We introduce nanodroplets to the site of the clot, and because the nanodroplets are so small, they are able to penetrate and convert to microbubbles within the clots when they are exposed to ultrasound," explains Leela Goel, first author of a paper on this work in Microsystems & Nanoengineering. Goel is a PhD student in the joint biomedical engineering department at North Carolina (NC) State University and the University of North Carolina (UNC) at Chapel Hill.
After the microbubbles form within the clots, the continued exposure of the clots to ultrasound oscillates the microbubbles. This rapid vibration causes the microbubbles to behave like tiny jackhammers, disrupting the physical structure of the clots and helping to dissolve them. This vibration also creates larger holes in the clot mass that allow blood-borne anti-clotting drugs to penetrate deep into the clot and further break it down.
The technique is made possible by the ultrasound drill – which is an ultrasound transducer that is small enough to be introduced to the blood vessel via a catheter. The drill can aim ultrasound directly ahead, which makes it extremely precise. It is also able to direct enough ultrasound energy to the targeted location to activate the nanodroplets, without causing damage to surrounding healthy tissue. The drill incorporates a tube that allows users to inject nanodroplets at the site of the clot.
In in vitro testing, the researchers compared the new technique with various combinations of drug treatment, microbubbles and ultrasound for eliminating blood clots.
"We found that the use of nanodroplets, ultrasound and drug treatment was the most effective, decreasing the size of the clot by 40%, plus or minus 9%," says Xiaoning Jiang, professor of mechanical and aerospace engineering at NC State and corresponding author of the paper. "Using the nanodroplets and ultrasound alone reduced the mass by 30%, plus or minus 8%. The next best treatment involved drug treatment, microbubbles and ultrasound – and that reduced clot mass by only 17%, plus or minus 9%. All these tests were conducted with the same 30-minute treatment period.
"These early test results are very promising."
"The use of ultrasound to disrupt blood clots has been studied for years, including several substantial studies in patients in Europe, with limited success," says co-author Paul Dayton, professor of biomedical engineering at UNC and NC State. "However, the addition of the low-boiling-point nanodroplets, combined with the ultrasound drill, has demonstrated a substantial advance in this technology."
"Next steps will involve pre-clinical testing in animal models that will help us assess how safe and effective this technique may be for treating deep vein thrombosis," says Zhen Xu, a professor of biomedical engineering at the University of Michigan and co-author of the paper.
Reactive molecules such as free radicals can be produced in the body after exposure to certain environments or substances and go on to cause cell damage. Antioxidants can minimize this damage by interacting with the radicals before they affect cells.
A team of researchers has now applied this concept to the task of preventing imaging damage to the conducting polymers found in soft electronic devices such as organic solar cells, organic transistors, bioelectronic devices and flexible electronics. The researchers, led by Enrique Gomez, professor of chemical engineering and materials science and engineering at Penn State, report their findings in a paper in Nature Communications.
According to Gomez, visualizing the structures of conducting polymers is crucial to the further development of these materials and their commercialization in soft electronic devices – but the imaging process can cause damage to the polymers that limits what researchers can see and understand.
"It turns out antioxidants, like those you'd find in berries, aren't just good for you but are also good for polymer microscopy," Gomez said.
Polymers can only be imaged to a certain point with high-resolution transmission electron microscopy (HRTEM), because the bombardment of electrons used to form images breaks the sample apart. The researchers examined this damage with the goal of identifying its fundamental cause.
They found that the HRTEM electron beam generates free radicals that degrade the sample's molecular structure. But introducing butylated hydroxytoluene, an antioxidant often used as a food additive, to the polymer sample prevented this damage and removed another restriction on imaging conditions – temperature.
"Until now, the main strategy for minimizing polymer damage has been imaging at very low temperatures," said paper co-author Brooke Kuei, who recently earned her doctorate in materials science and engineering in the Penn State College of Earth and Mineral Sciences. "Our work demonstrates that the beam damage can be minimized with the addition of antioxidants at room temperature."
Although the researchers did not quantitatively test the resolution limits that resulted from this method, they were able to image the polymer at a resolution of 3.6 angstroms, an improvement on their previous resolution of 16 angstroms.
Polymers are made up of molecular chains lying on top of each other. The previous resolution of 16 angstroms was the distance between chains, but imaging at 3.6 angstroms allowed the researchers to visualize patterns of close contacts along the chains. For the electrically conductive polymer examined in this study, this meant the researchers could follow the direction along which electrons travel. According to Gomez, this allows them to better understand the conductive structures in the polymers.
"The key to this advancement in polymer microscopy was understanding the fundamentals of how the damage occurs in these polymers," Gomez said. "This technological advance will hopefully help lead to the next generation of organic polymers."
This story is adapted from material from Penn State, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.
This method provides a new route to convert abundant carbon sources to high-value materials with ecological and economic benefitsTe-Yu Chien
Researchers at the University of Wyoming have shown how to easily and cheaply convert coal powder into graphite using just copper foil, glass containers and a standard microwave oven. With the demand for coal declining due to climate change, this breakthrough in pulverizing coal powder into nano-graphite – which is used as a lubricant and in a range of products such as lithium-ion batteries and fire extinguishers – could help identify new uses for coal.
Although previous studies had used microwaves to reduce the moisture content of coal, as well as remove sulfur and other minerals, these approaches tend to depend on chemical pre-treatment of the coal and are problematic due to the complexity and interpretation of the results. However, as reported in the journal Nano-Structures & Nano-Objects [Masi et al. Nano-Struct. Nano-Objects (2020) DOI: 10.1016/j.nanoso.2020.100660], here raw coal powder was converted into nano-graphite in a single stage approach based around four factors: high temperature, a reducing environment, a catalyst and microwave radiation.
Raw coal was first ground into powder, before it was positioned on copper foil and sealed in a glass vial with a gas mixture of argon and hydrogen, and then put into a conventional household microwave oven. Sparks produced by the microwaves made the high temperatures required to change the coal powder into polycrystalline graphite, a process that was also facilitated by the copper foil and hydrogen gas. On testing microwave durations of up to 45 minutes, it was found that the best duration was 15 minutes.
With finite graphite reserves and environmental concerns about how it is extracted, this new approach to coal conversion could be refined to offer a higher quality and quantity of nano-graphite materials. As team leader TeYu Chien said, “This method provides a new route to convert abundant carbon sources to high-value materials with ecological and economic benefits”.
Further research is needed to assess if their approach is viable at a larger scale, and if it is possible to extract or isolate the converted graphite from the non-converted matrix. However, modifying the recipe could lead to new possibilities of treating coal and other materials of interest, and the team have already tried using plastic powder from a conventional plastic water bottle. Various functional and complex materials could also be produced by changing the metal used, or the temperature, or varying the source materials to target different areas, while modifying the environment could provide different reactions such as doping.
Almost 600 thousand PLN of funding from the NCS will be granted to researchers from the Faculty of Electronics for their research into lifelong machine learning. They will collaborate on the project with researchers from the Czech Republic.
The Powder Coating Institute (PCI) has released the fifth edition of Powder Coating: The Complete Finisher’s Handbook.
According to the institute, the 485-page handbook is a guide for those performing powder coating operations or interested in learning more about powder coating technology.
‘The 5th edition of the powder coating handbook is a complete update to every chapter covering the latest trends and technologies,’ said PCI education committee chairman Greg Dawson. ‘PCI has a vast pool of members that worked incredibly hard to produce the latest edition in what is recognized as the authoritative resource manual on powder coating. Contributing authors to the fifth edition include professionals from every discipline you’ll require to become a powder coating expert.’
The handbook covers powder coating materials, production analysis, surface preparation, application methods and equipment, powder recovery, curing, maintenance, quality testing, troubleshooting, and much more. It also features appendices with PCI technical briefs and recommended test procedures along with a system troubleshooting guide and a maintenance checklist, the PCI said.
The handbook is available to PCI members for US$60.00 plus shipping and US$120.00 plus shipping for non-members. It can be ordered here.
This story uses material from the PCI, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier.
A range of honeycomb material is being used to make parts by two automotive manufacturers in Mexico.
Fynotej, which licences EconCore material in the country, has reportedly secured two major contracts to supply 120,000 m2 of trunk load floors over two years. One contract is for a new, not yet launched project and the other is for a current, already in production platform, the company said.
According to EconCore, the material can help save fuel and reduce CO2. The product is typically made from 30% recycled content, making it a more sustainable and environmentally friendly product. In this automotive application, the honeycomb core panel is made from polypropylene (PP), and Fynotej uses a proprietary inline lamination process that can laminate panels with non-woven automotive carpets by thermofusion without using adhesives.
‘We know vehicle manufacturers, as they transition to electric and hybrid cars, see light-weighting as a critical area for development, to increase the range of these vehicles,’ said Fynotej’s Fabiola Carbajal, sales manager.
This story uses material from Econcore, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier.
Markforged, which makes metal and carbon fiber 3D printers, has distributed a number additive manufacturing (AM) machines to manufacturers in Michigan, USA as part of Project DIAMOnD, a group of manufacturers focused on 3D printing personal protective equipment (PPE).
According to the company, more than 200 manufacturers have already received the printers and are ready to print PPE when required. In the meantime, they can also use the printers to make parts as part of their manufacturing operations.
‘The project is poised to become the world’s largest emergency response network for printing physical objects on demand,’ a press release said. ‘The project will also create supply chain resiliency and flexibility by presenting an opportunity for the participating manufacturers to print the parts they might need to keep their lines operational and versatile in the face of future disruption.’
‘Traditionally, governments have maintained special networks dedicated to the distribution of information and goods during emergencies, but this will be the first response network capable of actually manufacturing tangible parts and objects on demand as needs arise,’ said Michael Kelly, director at Markforged.
This story uses material from Markforged, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier.
Francisco José Pena Benitez, PhD will receive almost 200,000 EUR for conducting research and assembling a research team to work at WUST’s W11. The funding comes from the POLS competition organised by the National Centre for Science.
Inspired by the color-changing skin of cuttlefish, octopuses and squids, engineers at Rutgers University have created a 3D-printed smart gel that changes shape when exposed to light. This allows the gel to act as 'artificial muscle', and may lead to new military camouflage, soft robotics and flexible displays.
The engineers also developed a 3D-printed stretchy material that can reveal colors when the light changes, according to a paper on this work in ACS Applied Materials & Interfaces.
Their invention is modeled after the amazing ability of cephalopods such as cuttlefish, octopuses and squids to change the color and texture of their soft skin for camouflage and communication. This is achieved by thousands of color-changing cells, called chromatophores, in their skin.
"Electronic displays are everywhere and despite remarkable advances, such as becoming thinner, larger and brighter, they're based on rigid materials, limiting the shapes they can take and how they interface with 3D surfaces," said senior author Howon Lee, an assistant professor in the Department of Mechanical and Aerospace Engineering in the School of Engineering at Rutgers University-New Brunswick. "Our research supports a new engineering approach featuring camouflage that can be added to soft materials and create flexible, colorful displays."
The 3D-printed smart gel is based on a hydrogel, which is mainly composed of water but is still able to keep its shape and stay solid. Hydrogels are found in the human body, Jell-O, diapers and contact lenses, among many other examples.
The engineers incorporated a light-sensing nanomaterial into the hydrogel, turning it into an 'artificial muscle' that contracts in response to changes in light. When combined with the 3D-printed stretchy material, this light-sensing smart gel can also change color, resulting in a camouflage effect.
Next steps will include improving the technology's sensitivity, response time, scalability, packaging and durability.
This story is adapted from material from Rutgers University, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.
Engineers at the University of Maryland (UMD) have created a new shape-changing, or 'morphing', 3D printing nozzle, which they report in a paper in Advanced Materials Technologies.
The team's morphing nozzle offers researchers new means for 3D printing 'fiber-filled composites' – materials made up of short fibers that offer several advantages over traditional 3D-printed parts, such as enhanced part strength and electrical conductivity. But these properties are based on the directions or 'orientations' of the short fibers, which has been difficult to control during the 3D printing process, until now.
"When 3D printing with the morphing nozzle, the power lies on their side actuators, which can be inflated like a balloon to change the shape of the nozzle, and in turn, the orientations of the fibers," said Ryan Sochol, an assistant professor in mechanical engineering and director of the Bioinspired Advanced Manufacturing (BAM) Laboratory at UMD's A. James Clark School of Engineering.
To demonstrate their new approach, the researchers set their sights on emerging '4D printing' applications. "4D printing refers to the relatively new concept of 3D printing objects that can reshape or transform depending on their environment," said UMD mechanical engineering professor David Bigio, a co-author of the study. "In our work, we looked at how printed parts swelled when submerged in water, and specifically, if we could alter that swelling behavior using our morphing nozzle."
Recent advances in 4D printing rely on materials capable of both 'anisotropic' expansion – swelling more in one direction than another – and 'isotropic' expansion – swelling identically in all directions. Unfortunately, switching between these conditions has typically required researchers to print with several different materials.
"What was exciting was discovering that we could cause a single printed material to transition between anisotropic and isotropic swelling just by changing the nozzle's shape during the 3D printing process," said Connor Armstrong, lead author of the paper. Armstrong developed the approach as part of his MS thesis research at UMD.
"Importantly, the nozzle's ability to morph and to even up the score in terms of swelling properties is not limited to 4D printing," said study co-author and recently graduated mechanical engineering undergraduate student Noah Todd. "Our approach could be applied for 3D printing many other composite materials to customize their elastic, thermal, magnetic or electrical properties for example."
Interestingly, to build the morphing nozzle itself, the team actually turned to a different 3D printing technology called 'PolyJet Printing'. This multi-material inkjet-based approach, offered by UMD's Terrapin Works 3D Printing Hub, allowed the researchers to 3D print their nozzle with flexible materials for the inflatable side actuators and the shape-changing central channel, and rigid materials for the outer casing and the access ports.
"The use of multi-material PolyJet 3D printing enabled us to design the nozzle with an operating power range or set of pressure magnitudes that can be reproduced in essentially any research laboratory," said study co-author and mechanical engineering PhD candidate Abdullah Alsharhan.
The team is now exploring the use of its morphing nozzle to realize biomedical applications in which bulk printed objects could reshape in the presence of particular stimuli from the body. It is also in discussions with several US Department of Defense laboratories to use the morphing nozzle to support the production of weapons for defense and other military systems.
"By providing researchers with an accessible way to 3D print fiber-filled composite materials with on-demand control of their fiber orientations, and thus their ultimate performance, this work opens the door for new applications of 3D printing that harness these unique material properties and the distinctive capabilities they enable," said Sochol.
This story is adapted from material from the University of Maryland, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.
63 fields of study, including 21 in English, three novelties, over four thousand free places are the basic facts summing up the offering of Wrocław University of Science and Technology in the winter enrolment time. The enrolments end on February 12.
The ubiquity of artificial intelligence in the manufacturing domain draws inspiration for the present article. The implementation of a neural network technique is still a difficult and time-consuming effort for the industry. Prediction of machining variables is a considerable issue that needs to be explored for preventive maintenance of the machine structure and to optimize the surface quality. This work aims at predicting response parameters of the dry turning process for Inconel 825 alloy using deep-cryogenic treated tungsten-carbide insert through artificial neural network technique. Process parameters considered in this work were cutting speed, feed and depth of cut, whereas, surface-roughness, tool-wear, and material-removal-rate were taken as the three response parameters.14 types of training functions were compared based upon their error indices searching for the training function which best suits this work. Artificial Neural Network (ANN) model was developed by taking Bayesian regularization back propagation based training function. The response values predicted by the ANN were in very close approximation to the actual experimental value with the mean square error of only 0.0011?μm2, 39.0882?μm2 and 0.0520?cm6/min2in the prediction of surface-roughness, tool-wear, and material-removal-rate of dry turning process of Inconel 825 using treated carbide tool.
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Hermann Staudinger published “On Polymerization” in 1920, insightfully describing the chemical structures of the molecules that were produced by polymerization reactions. This POLYMER Special Issue commemorates the “On Polymerization” Centennial by celebrating contemporary polymer science and engineering with papers that describe the myriad and complex macromolecular architectures and arrangements that have generated the incredible variety of polymeric materials that exist today. Ironically, Staudinger produced his seminal work during the Spanish flu pandemic and this Centennial Special Issue was published during the COVID-19 pandemic. The prominent and indispensable role of polymers in today’s world is exemplified by the ubiquitous masks and gloves that were integral to our achieving a modicum of normalcy during these extremely difficult times.
ASTM International has announced that all its previously scheduled in-person April standards development meetings (including independent meetings) have been canceled.
According to the organization, this decision follows continued review of information and recommendations from the US Centers for Disease Control and Prevention (CDC), the World Health Organization (WHO), and other governmental bodies, input from ASTM International members whose organizations are increasingly concerned with travel, and specific information on the projected city restrictions in Toronto, Ontario, CA, and other cities.
Olympus has developed a new scanner that it says makes it easier to inspect composite components with large surface areas.
According to the company, while ultrasonic testing is a standard nondestructive method for composites, extensive surface area, the attenuative nature of composites and the complicated operation of some ultrasonic testing equipment can cause problems.
The RollerFORM XL scanner features an integrated phased array probe which can reportedly provide a beam coverage that is twice as wide. Scanning large parts is more efficient and the data’s accuracy is improved since the wider beam coverage also increases the probability of detection, according to Olympus.
It takes less effort to set up and inspect compared with immersion-based testing and can obtain stronger, more reliable signals without a couplant pumping system due to the scanner’s tire. Interface reflections are minimized because the tire is filled with liquid and the material has an acoustic impedance that closely matches water, and this similarity enables the ultrasound beam energy to transmit efficiently into the part, the company said. The RollerFORM XL scanner also has an encoder, an indexing button and a start acquisition button to facilitate complete scans of large wings or blades.
This story uses material from Olympus, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier.
The US National Institute of Standards and Technology (NIST) has awarded nearly US$4 million in grants to develop 3D printing measurement methods and standards.
According to NIST, additive manufacturing (AM) standards require improvement with regards to surface finish and quality issues, dimensional accuracy, fabrication speed, material properties and computational requirements.
The Institute will fund four research projects:
Georgia Tech Research Corporation (US$1 million)
This project will analyze data gathered during a powder bed fusion process to control the manufacturing and predict the final properties of the manufactured parts. The goal is to establish a comprehensive basis to qualify, verify and validate parts produced by this technique. The initial focus will be on a titanium alloy for the health care and aerospace sectors.
University of Texas at El Paso (US$1 million)
This project will define a test artifact to standardize the collection of data on the process inputs and performance of parts made via laser powder bed fusion. Academic, government and industrial partners will replicate the artifact and collect data on the key inputs to the process and the resulting properties of the artifact for a data repository. The work will lead to a greater understanding of the AM process and will allow for greater confidence in final parts.
Purdue University (US$999,929)
This project aims to reduce the time required to qualify AM parts by developing a standardized approach to predict key performance properties by measuring material microstructures and the use of mathematical models. The work aims to create a streamlined method for industry to understand part performance with less testing than is currently required.
Northeastern University (US$999,464)
This project aims to improve sensing approaches and create a suite of sensor technologies that will help improve cold spray AM. Cold spray AM processes have the potential to create parts that are more durable and stronger than those made with other AM processes. New sensors will help characterize the properties of the powder feedstock and the key parameters of the process, such as temperatures and part dimensions, and allow for better control of this promising technique.
NIST says that it also plans to fund additional projects as part of a second phase of awards in the first half of 2021.
‘By addressing important measurement challenges, these projects will improve US manufacturers’ ability to use metals-based additive manufacturing to make high-quality, innovative and complex products at high volume,’ said NIST director Walter G Copan.
This story uses material from the NIST, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier.
"Our machine-learning framework achieves essentially the same accuracy as the high-fidelity model but at a fraction of the computational cost."Rémi Dingreville, Sandia National Laboratories
A research team at Sandia National Laboratories has successfully used machine learning – computer algorithms that improve themselves by learning patterns in data – to complete cumbersome materials science calculations more than 40,000 times faster than normal.
Their results, reported in a paper in npj Computational Materials, could herald a dramatic acceleration in the creation of new technologies for optics, aerospace, energy storage and potentially even medicine while simultaneously saving laboratories money on computing costs.
"We're shortening the design cycle," said David Montes de Oca Zapiain, a computational materials scientist at Sandia who helped lead the research. "The design of components grossly outpaces the design of the materials you need to build them. We want to change that. Once you design a component, we'd like to be able to design a compatible material for that component without needing to wait for years, as it happens with the current process."
The research, funded by the US Department of Energy (DOE)'s Basic Energy Sciences program, was conducted at the Center for Integrated Nanotechnologies, a DOE user research facility jointly operated by Sandia and Los Alamos national labs.
Sandia researchers used machine learning to accelerate a computer simulation that predicts how changing a design or fabrication process, such as tweaking the amounts of metals in an alloy, will affect a material. A project might require thousands of these simulations, which can take weeks, months or even years to run.
The team clocked a single, unaided simulation on a high-performance computing cluster with 128 processing cores (a typical home computer has two to six processing cores) at 12 minutes. With machine learning, however, the same simulation took 60 milliseconds using only 36 cores, equivalent to 42,000 times faster on equal computers. This means researchers can now learn in under 15 minutes what would normally take a year.
Sandia's new algorithm arrived at an answer that was 5% different from the standard simulation's result, a very accurate prediction for the team's purposes. Machine learning trades some accuracy for speed because it makes approximations to shortcut calculations.
"Our machine-learning framework achieves essentially the same accuracy as the high-fidelity model but at a fraction of the computational cost," said Sandia materials scientist Rémi Dingreville, who also worked on the project.
Dingreville and Montes de Oca Zapiain are initially going to use their algorithm to research ultrathin optical technologies for next-generation monitors and screens. But their research could prove widely useful, because the simulation they accelerated describes a common event – the change, or evolution, of a material's microscopic building blocks over time.
Machine learning has previously been used to shortcut simulations that calculate how interactions between atoms and molecules change over time. This study, however, demonstrates the first use of machine learning to accelerate simulations of materials at relatively large, microscopic scales, which the Sandia team expects will be of greater practical value to scientists and engineers.
For instance, scientists can now quickly simulate how miniscule droplets of melted metal will glob together when they cool and solidify, or conversely, how a mixture will separate into layers of its constituent parts when it melts. Many other natural phenomena, including the formation of proteins, follow similar patterns. And while the Sandia team has not yet tested the machine-learning algorithm on simulations of proteins, they are interested in exploring this possibility in the future.
Due to their versatile properties, polymers are used for a variety of purposes. For example, polymers with high tensile strength and resistance can be used in construction, while polymers that are more lightweight and flexible can be used to manufacture plastic bags.
These differences in the properties of different polymers stem from their internal structure. Polymers are made up of long chains of smaller sub-units, called 'monomers'. Crystallization occurs when crystalline polymers are first melted then cooled down slowly, which allows the chains to organize themselves into neatly arranged plates.
Depending on the degree and location of crystallization, this process can provide polymers with various properties, including flexibility, heat conductivity and strength. However, if not properly controlled, crystallization can also weaken the material, putting undue stress on the polymer chains. This is especially problematic when polymers are subjected to extreme conditions, such as freezing temperatures or intense pressure.
Guaranteeing optimal performance requires predicting how a given polymer will react to mechanical stress and to what degree crystallization contributes to this response. But scientists know very little about the intricate forces at play during crystallization, having never been able to observe them directly or measure them accurately without destroying the material first.
Based on recent advances in polymer science, a research group led by Hideyuki Otsuka from Tokyo Institute of Technology in Japan has been working on a method to visualize polymer crystallization in real time. As the group reports in a paper in Nature Communications, this method is based on embedding reactive molecules called radical-type 'mechanophores' in the polymer structures.
Radical-type mechanophores are sensitive to mechanical stress and easily break down into two equivalent radical species, which can act as probes for determining when and how stress is applied. In this case, to examine the mechanical forces at play during crystallization, the researchers used a radical-type mechanophore called tetraarylsuccinonitrile (TASN), which breaks down and emits fluorescence when subjected to mechanical stress.
The team had already used similar molecules to visualize and evaluate the degree of mechanical stress within a polymer material. In the current study, they used a similar method to observe the crystallization of a polymer.
As the crystals form, the mechanical forces cause the mechanophores in the polymer structure to dissociate into smaller, pink-colored radicals with a characteristic yellow fluorescence, allowing the team to observe the crystallization process. By measuring the emitted wavelengths of the fluorescence, the researchers are able to determine the exact rate of crystallization, as well as its extent and precise location within the polymer material.
"The direct visualization of polymer crystallization offers unprecedented insight into crystal growth processes," says Otsuka. This method could now allow manufacturers to test polymer materials for specific mechanical properties during crystallization. The researchers believe their study will permit the industrial optimization of polymer materials by controlling the crystallization process to obtain desired properties. Ultimately, Otsuka concludes, this could "lead to design guidelines for advanced polymer materials".
The MPIF has published the program for MIM2021: International Conference on Injection Molding of Metals, Ceramics and Carbides, taking place virtually from 22-25 February 2021.
According to the company, the keynote presentations will cover metal working for surgical instruments and MIM components for golf equipment.
Other events will include a powder injection molding tutorial, three days of technical sessions and a virtual exhibition.
‘The metal injection molding industry is an innovative and highly competitive marketplace,’ said Paul Sedor, vice president, MPIF. ‘The annual MIM conference provides an optimal venue for gaining industry insight and learning about the latest technology.’
Last year’s MIM2020 attendees consisted of 38% parts manufacturers; 30% equipment & service providers; 11% powder and feedstock suppliers; 5% consumers; and 16% other, which includes students and academia. A similar attendance base is expected for 2021, the MPIF said.
Ceratizit says that it has won an innovation award for developing a new way to 3D print tungsten carbide-cobalt.
The company was recognized by FEDIL, a Luxembourgian business networking company, in its process category.
‘The additive manufacturing [AM] of components made of plastic, steel and other materials has continued to grow in importance over the last few years,’ the company said. ‘However, in the case of cemented carbide, there had not been a reliable process so far that achieved the same standard of quality as the manufacturing processes that had been established and optimised over decades.’
According to Ceratizit, another advantage of AM carbide is being able to make small, highly complex parts such as prototypes, without requiring production-intensive shapes and dies as well as the expensive, diamond-tipped tools which are needed for the machining of carbide parts.
It is also possible to print structures with undercuts or areas inaccessible to cutting tools such as cavities and channels inside the finished body, which cannot be accessed from outside at a later stage, the company said.
This story uses material from Ceratizit, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier.
Scott Bader Co Ltd has partnered with Pultex GmbH to distribute its composite structural adhesives in Germany.
Pultex also offers the adhesive dispensing equipment required for Scott Bader’s Crestabond and Crestomer adhesives, the company said.
‘Scott Bader and their products complete our range and offers us new possibilities to meet the increasing demands of our customers for high-quality adhesives,’ said Guido Bongard, MD at Pultex, said. ‘The intersections of our business areas are high.
This story uses material from Scott Bader, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier.
Polynt Composites has raised the price of its UPR and gelcoats by €100/ton.
The company says that it has also raised the price of its range of vinylester by €180/ton.
The price raises will be effective from 15 January or as agreements allow in Europe, the Middle East, and Africa.
According to Polynt, this is due to a ‘further extraordinary escalation of UPRs raw material and logistic cost’. ‘Polynt Composites will continue to work hard to limit the impact of rising costs and raw material availablw upon product pricing and supply,’ a press release said.
This story uses material from Polynt, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier.
Polarons are fleeting distortions in a material's atomic lattice that form around a moving electron in a few trillionths of a second, then quickly disappear. As ephemeral as they are, they can affect a material's behavior, and may even be the reason that solar cells made with lead hybrid perovskites achieve such extraordinarily high efficiencies in the lab.
Now, scientists at the US Department of Energy (DOE)'s SLAC National Accelerator Laboratory and Stanford University have used the lab's X-ray laser to watch and directly measure the formation of polarons for the first time. They report their findings in a paper in Nature Materials.
"These materials have taken the field of solar energy research by storm because of their high efficiencies and low cost, but people still argue about why they work," said Aaron Lindenberg, an investigator with the Stanford Institute for Materials and Energy Sciences (SIMES) at SLAC and an associate professor at Stanford, who led the research.
"The idea that polarons may be involved has been around for a number of years. But our experiments are the first to directly observe the formation of these local distortions, including their size, shape and how they evolve."
Perovskites are crystalline materials named after the mineral perovskite, which has a similar atomic structure. Scientists started to incorporate perovskites into solar cells about a decade ago. Since then, the efficiency of these cells at converting sunlight to energy has steadily increased, despite the fact that the perovskite components have a lot of defects that should inhibit the flow of current.
These materials are famously complex and hard to understand, Lindenberg said. Scientists find them exciting because they are both efficient and easy to produce, raising the possibility that they could make solar cells cheaper than today's silicon cells. But they are also highly unstable, breaking down when exposed to air, and contain lead that has to be kept out of the environment.
Previous studies at SLAC have delved into the nature of perovskites with an 'electron camera' or with X-ray beams. Among other things, these studies revealed that light whirls atoms around in perovskites; they also measured the lifetimes of acoustic phonons – sound waves - that carry heat through the materials.
For this study, Lindenberg's team used SLAC's Linac Coherent Light Source (LCLS), a powerful X-ray free-electron laser that can image materials in near-atomic detail and capture atomic motions occurring over millionths of a billionth of a second. They investigated single crystals of hybrid perovskite, synthesized by Hemamala Karunadasa's group at Stanford, by hitting the crystals with light from an optical laser and then using the X-ray laser to observe how they responded over the course of tens of trillionths of a second.
"When you put a charge into a material by hitting it with light, like what happens in a solar cell, electrons are liberated, and those free electrons start to move around the material," explained Burak Guzelturk, a scientist at DOE's Argonne National Laboratory who was a postdoctoral researcher at Stanford at the time of the experiments.
"Soon they are surrounded and engulfed by a sort of bubble of local distortion – the polaron – that travels along with them. Some people have argued that this 'bubble' protects electrons from scattering off defects in the material, and helps explain why they travel so efficiently to the solar cell's contact to flow out as electricity."
The hybrid perovskite lattice structure is flexible and soft – like "a strange combination of a solid and a liquid at the same time", as Lindenberg puts it – and this is what allows polarons to form and grow.
The scientists' observations revealed that polaronic distortions start very small – on the scale of a few angstroms, about the spacing between atoms in a solid – and rapidly expand outward in all directions to a diameter of around five billionths of a meter, which is about a 50-fold increase. This nudges about 10 layers of atoms slightly outward within a roughly spherical area over the course of tens of picoseconds, or trillionths of a second.
"This distortion is actually quite large, something we had not known before," Lindenberg said. "That's something totally unexpected.
"While this experiment shows as directly as possible that these objects really do exist, it doesn't show how they contribute to the efficiency of a solar cell. There's still further work to be done to understand how these processes affect the properties of these materials."
Spintronics refers to a suite of physical systems that may one day replace many electronic systems. To realize this generational leap, material components that confine electrons in one dimension are highly sought after. For the first time, researchers have now created such a material, known as a higher-order topological insulator, in the form of a special bismuth-based crystal.
For spintronic applications, a new kind of electronic material is required, and it's called a topological insulator. A topological insulator differs from a conductor, insulator or semiconductor because it's insulating throughout its bulk but conducting along its surface. And what it conducts is not the flow of electrons themselves, but a property of electrons known as their spin or angular momentum. This spin current, as it's known, could open up a new world of ultrahigh-speed and low-power electronic devices.
However, not all topological insulators are equal. Two kinds, so-called strong and weak, have already been created, but they have some drawbacks: as they conduct spin along their entire surface, the electrons present tend to scatter, which weakens their ability to convey a spin current. But since 2017, a third kind of topological insulator, called a higher-order topological insulator, has been theorized.
Now, for the first time, this third kind of topological insulator has been created by a team from the Institute for Solid State Physics at the University of Tokyo in Japan. The team reports its advance in a paper in Nature Materials.
"We created a higher-order topological insulator using the element bismuth," said Takeshi Kondo, an associate professor at the University of Tokyo. "It has the novel ability of being able to conduct a spin current along only its corner edges, essentially one-dimensional lines. As the spin current is bound to one dimension instead of two, the electrons do not scatter so the spin current remains stable."
To create this three-dimensional crystal, Kondo and his team stacked two-dimensional slices of crystal one atom thick in a certain way. For strong or weak topological insulators, crystal slices in the stack are all oriented the same way, like playing cards face down in a deck. But to create the higher-order topological insulator, the researchers alternated the orientation of the slices: the metaphorical playing cards were placed face up and then face down repeatedly throughout the stack. This subtle change in arrangement makes a huge change to the behavior of the resultant three-dimensional crystal.
The crystal layers in the stack are held together by a quantum mechanical force called the van der Waals force. This is one of the rare kinds of quantum phenomena that has a noticeable effect in daily life, as it is partly responsible for the way that powdered materials clump together and flow. In the crystal, it adheres the layers together.
"It was exciting to see that the topological properties appear and disappear depending only on the way the two-dimensional atomic sheets were stacked," said Kondo. "Such a degree of freedom in material design will bring new ideas, leading toward applications including fast and efficient spintronic devices, and things we have yet to envisage."
This story is adapted from material from the University of Tokyo, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.
PyroGenesis Canada, which specializes in plasma atomized metal powder, has submitted a formal application to list its common shares on the NASDAQ Stock Exchange.
‘We believe the company is entering a heightened growth phase and the timing could not be better for uplisting our Shares to NASDAQ,’ said P Peter Pascali, CEO. ‘We expect that the move to NASDAQ will increase awareness of PyroGenesis, and its offerings, both within the financial community and amongst potential clients.’
This story uses material from PyroGenesis, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier.
A group of companies in the North of England has been formed to help accelerate the bioscience sector in the Tees Valley.
Plans are for the Northern Bio-Accelerator Partnership (NBioP) to create a bioprocessing, biomanufacturing and biopharmaceutical hub in based at Darlington’s Central Park.
‘With a high-density cluster of expertise and a well-developed business ecosystem, the North East offers a bioscience community that is second to none in the UK,’ a press release said. ‘Access to a mature supply chain and highly-skilled workforce, with much lower business costs than other areas of the UK, means a start-up company can establish itself in the region for life.’
This story uses material from Tees University, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier.
Notus Composites, based in United Arab Emirates, says that it has made its final shipment of fire retardant (FR) epoxy prepreg to be used in Dubai’s Museum of the Future.
According to Notus, over 600,000 m2 of prepreg materials have been supplied for the building’s external façade panels. The museum, which will focus on design and innovation, also features 1024 cladding panels built using a combination of Notus’ multiaxial glass and carbon prepregs. The EPFR-609 prepregs and NE11FR surfacing films have been approved by the Dubai Civil Defence (DCD), the company said.
A facade panel in the Museum of the Future featuring fire retardant (FR) epoxy prepreg.
This story uses material from Notus, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier.
Stratasys Ltd has completed its acquisition of Origin, which makes additive manufacturing (AM) systems.
‘The completion of this acquisition marks an important milestone for Stratasys, positioning us to generate meaningful incremental revenue from a wide range of new market opportunities for mass production,’ said Stratasys CEO Yoav Zeif. ‘I’m confident that Origin’s innovative solutions will be a key contributor to strong company growth beginning in 2021.’
This story uses material from Stratasys, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier.
Biodegradable metals such as iron, magnesium, and zinc could make ideal temporary bone substitutes because they degrade gradually as new bone regrows. Researchers from Delft University of Technology have taken a systematic look at porous iron, which is stronger than either magnesium or zinc, to assess its potential as a scaffold for bone repair [Putra et al., Acta Biomaterialia (2020), https://doi.org/10.1016/j.actbio.2020.11.022].
"In comparison with other biodegradable metals or polymers for bone implants, iron has a high mechanical strength, which allows for the design and fabrication of porous structures for the treatment of critical bony defects," says Amir A. Zadpoor, who led the study.
Iron is also used by the body to transport oxygen, accelerates enzyme reactions, plays a role in the immune system, and is essential to bone regeneration. But previous attempts to make bone scaffolds using fabrication methods used to, such as powder bed fusion, had limitations. So Zadpoor and his colleagues developed an alternative additive manufacturing technology using extrusion-based 3D printing.
"We wanted to verify the feasibility of applying extrusion-based 3D printing to fabricate porous iron and explore the potential of resolving the fundamental issue of bulk iron, which has a very low biodegradation rate, while maintaining other important properties such as structural integrity and mechanical properties during the bone healing period," say Zadpoor and coauthors Niko E. Putra and Jie Zhou.
In this approach, particulate iron is mixed with a polymer solution to form an ink, which is deposited layer by layer to build up a three-dimensional structure. The scaffold is heated, initially to drive off the polymer, and then at a higher temperature to fuse the iron particles together into a porous solid. The iron forms a hierarchical structure with macroscale pores and micropores within the supporting struts. When immersed in simulated body fluid, the porous iron has an accelerated biodegradation rate, losing 7% of its mass over 28 days, because of its much larger surface area.
Corrosion occurs throughout the scaffold, even inside the pores, creating a mixture of iron-, oxygen-, and carbon-rich products and trace elements including sodium, calcium, and phosphorus. The scaffold’s mechanical properties, however, remain within the range of porous bone.
"[We have confirmed] that extrusion-based 3D printing can deliver porous iron scaffolds with enhanced biodegradability and bone-mimicking mechanical properties for potential application as bone substitutes," say Zadpoor, Putra, and Zhou. "We are now exploiting the capabilities of this 3D printing technology to achieve other functionalities desired for bone-substitution applications."
Nanobioceramics could be fused with the iron scaffold to promote bone growth, as well as antibacterial agents to prevent infections or drugs to treat bone diseases.
Nature has figured out how to make great membranes: biological membranes let the right stuff into cells while keeping the wrong stuff out. They are remarkable and ideal for their job. But they're not necessarily ideal for high-volume, industrial jobs such as pushing saltwater through a membrane to remove salt and make fresh water for drinking, irrigating crops, watering livestock or creating energy.
Can we learn from those high-performing biological membranes? Can we apply nature's homogenous design strategies to manufactured polymer membranes? Can we quantify what makes some industrial membranes perform better than others?
Researchers from Iowa State University, the University of Texas (UT) at Austin, DuPont Water Solutions and Dow Chemical Co, led by Enrique Gomez at Penn State and Manish Kumar at UT Austin, have now used transmission electron microscopy and 3D computational modeling to find answers to these questions.
Iowa State's Baskar Ganapathysubramanian, a professor in engineering in the Department of Mechanical Engineering, and Biswajit Khara, a doctoral student in mechanical engineering, contributed their expertise in applied mathematics, high-performance computing and 3D modeling to the project.
The researchers found that creating a uniform membrane density down to the nanoscale of billionths of a meter is crucial for maximizing the performance of polymer membranes for water filtration. They report their findings in a paper in Science.
Working with Penn State's transmission electron microscope measurements of four different polymer membranes used for water desalination, the Iowa State engineers predicted water flow by developing 3D models of the membranes. This allowed a detailed comparative analysis of why some membranes performed better than others.
"The simulations were able to tease out that membranes that are more uniform – that have no 'hot spots' – have uniform flow and better performance," Ganapathysubramanian said. "The secret ingredient is less inhomogeneity."
These findings are highlighted in the image that graces the cover of the issue of Science containing their paper, which the Iowa State researchers created with assistance from the Texas Advanced Computing Center (see image). Red above the membrane shows water under higher pressure and with higher concentrations of salt; the gold, granular, sponge-like structure in the middle shows denser and less-dense areas within the salt-stopping membrane; silver channels show how water flows through; and the blue at the bottom shows water under lower pressure and with lower concentrations of salt.
"You can see huge amounts of variation in the flow characteristics within the 3D membranes," Khara said. Most telling are the silver lines showing water moving around dense spots in the membrane.
"We're showing how water concentration changes across the membrane." Ganapathysubramanian said of the models, which required high-performance computing to solve. "This is beautiful. It has not been done before because such detailed 3D measurements were unavailable, and also because such simulations are non-trivial to perform."
"The simulations themselves posed computational challenges, as the diffusivity within an inhomogeneous membrane can differ by six orders of magnitude," added Khara.
So, the researchers conclude, the key to better desalination membranes is figuring out how to measure and control the densities of manufactured membranes at very small scales. Manufacturing engineers and materials scientists need to make the density uniform throughout the membrane, thus promoting water flow without sacrificing salt removal.
This is one more example of how computational work from Ganapathysubramanian's lab is helping to solve a very fundamental yet practical problem. "These simulations provided a lot of information for figuring out the key to making desalination membranes much more effective," said Ganapathysubramanian, whose work on the project was partly supported by two grants from the US National Science Foundation.
This story is adapted from material from Iowa State University, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.
SINTX Technologies, which makes silicon nitride ceramic materials for medical and non-medical applications, will celebrate its 25th anniversary in 2021.
The company says that it recently developed antiviral materials for use in consumer facemasks following the Covid-19 pandemic, as well as silicon nitride embedded antimicrobial surfaces and protective medical equipment.
SINTX next plans to expand its business in 2021 by developing its formulations of silicon nitride composites and coatings, including a silicon nitride polyetheretherketone (PEEK) composite for the orthopedic implant market and silicon nitride coated titanium for joint implants.
‘We made meaningful progress in our R&D, made significant investments in new personnel and equipment, and identified new customers and opportunities during 2020, as we moved beyond manufacturing spinal implants,’ said D. Sonny Bal, CEO. ‘The company will apply its knowledge and technology toward generating revenue in 2021.’
This story uses material from SINTX, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier.
The British Plastics Federation (BPF) has launched a sustainability report focusing on the plastics supply chain, including sustainable manufacturing practices, sector-specific contributions to sustainability and end of life management.
According to the BFP, the report shows how the plastics industry is ‘contributing significantly to strengthening the market for secondary plastics materials, decreasing energy use in plastics processing, and setting new international standards’.
The report also features case studies on subjects such as reducing reliance on energy from the grid and sorting technology for plastic waste.
‘Because the plastics industry has been under such public scrutiny it has a far greater understanding of what sustainability means for an industrial material than any other sector,’ said chairman of BPF sustainability committee Jason Leadbitter.
‘Most major sectors depend on plastics to a greater or lesser degree: retail, automotive, aerospace, construction and healthcare, just to cite a few,’ added BPF director-general, Philip Law. ‘Gains in the sustainability of plastics are gains for these businesses and for the UK economy and environment as a whole.’
Bulk metallic glasses (BMGs) have outstanding mechanical properties but because the atoms in these amorphous materials do not have long-range order their properties are difficult to understand. Now researchers from the University of New South Wales (UNSW Sydney), University of Sydney, Austrian Academy of Sciences, and University of Leoben have uncovered hierarchical structure in BMGs at the nanoscale that determines their properties [Nomoto et al., Materials Today (2020), https://doi.org/10.1016/j.mattod.2020.10.032].
“BMGs are carefully alloyed and processed to avoid crystallization,” explains Jamie J. Kruzic of UNSW Sydney, who led the study. “Our ability to control their properties precisely is limited because we have difficulties observing and quantifying the structural arrangements of the atoms and understanding how those atomic arrangements control the final properties.”
The researchers turned to nanobeam electron diffraction (NBED) in a transmission electron microscope (TEM) to look for tell-tale atomic structural features in a promising class of Zr-based BMGs. As-cast material was deformed or subjected to cryogenic thermal treatment to create hard and soft regions. Cross-sections of the BMGs were then examined to reveal the amount and size of locally ordered atomic arrangements over the scale of a few nanometers, which is known as medium range order (MRO).
The analysis revealed that the size and volume fraction of MRO regions change with deformation or thermal treatment and, more importantly, larger MRO cluster sizes and higher volume fractions are associated with decreased local hardness.
“Our findings represent the first detailed experimental characterization of the hierarchical structure of BMGs,” says Kruzic. “We have connected the nanoscale structure to the microscale structure by revealing how local microscale hardness heterogeneities arise from differences in the MRO cluster size and volume fraction.”
The findings hold true for BMGs of different compositions, as well as after deformation or cryogenic thermal cycling. The ordering of atoms on a local scale within BMGs appears to be responsible for their mechanical properties rather than the presence of nanocrystals or chemical variations in the material. The researchers suggest that this could be the result of the presence of crystal- and icosahedral-like structures in BMGs. The atoms in crystal-like regions tend to take up a face-centered-cubic (FCC) like arrangement, which is softer than icosahedral regions. FCC-like MRO clusters also initiate the deformation of the harder, less ordered matrix, the researcher believe.
“Our findings present a new picture of the structural hierarchy existing in BMGs and provide a significantly improved understanding of their deformation mechanisms and how the glassy structure connects processing and mechanical properties,” says Kruzic. “This knowledge will be extremely useful in creating BMGs with controllable and reliable mechanical properties for applications in aerospace, transportation, biomedicine, and consumer products.”
Hydrogen is a sustainable source of clean energy that avoids toxic emissions and can add value to multiple sectors of the economy, including transportation, power generation and metals manufacturing, among others. Technologies for storing and transporting hydrogen bridge the gap between sustainable energy production and fuel use, and therefore are an essential component of a viable hydrogen economy. But traditional means of storing and transporting hydrogen are expensive and susceptible to contamination.
Researchers are therefore searching for alternative techniques that are reliable, low-cost and simple. More efficient hydrogen delivery systems would benefit many applications, such as stationary power, portable power and mobile vehicle industries.
Now, as reported in a paper in the Proceedings of the National Academy of Sciences, researchers have designed and synthesized an effective material for speeding up one of the limiting steps in extracting hydrogen from alcohols. The material is a catalyst made from tiny clusters of nickel metal anchored to a 2D substrate.
The team, led by researchers at Lawrence Berkeley National Laboratory (Berkeley Lab)'s Molecular Foundry, found that the catalyst could cleanly and efficiently accelerate the reaction that removes hydrogen atoms from a liquid chemical carrier. The material is robust and made from Earth-abundant metals rather than precious metals, and will help make hydrogen a viable energy source for a wide range of applications.
"We present here not merely a catalyst with higher activity than other nickel catalysts that we tested, for an important renewable energy fuel, but also a broader strategy toward using affordable metals in a broad range of reactions," said Jeff Urban, the Inorganic Nanostructures Facility director at the Molecular Foundry, who led the work.
Chemical compounds that act as catalysts are commonly used to increase the rate of a chemical reaction without the compound itself being consumed. They might hold a particular molecule in a stable position, or serve as an intermediary that allows an important step to be reliably completed.
For the chemical reaction that produces hydrogen from liquid carriers, the most effective catalysts are made from precious metals, but they are associated with high costs and low abundance, and are susceptible to contamination. Other less expensive catalysts, made from more common metals, tend to be less effective and less stable, which limits their activity and their practical deployment for hydrogen production.
To improve the performance and stability of these Earth-abundant metal-based catalysts, Urban and his colleagues modified a strategy that focuses on tiny, uniform clusters of nickel metal. Tiny clusters are important because they maximize the exposure of the reactive surface for a given amount of material. But these clusters also tend to clump together, which inhibits their reactivity.
Postdoctoral research assistant Zhuolei Zhang and project scientist Ji Su, both at the Molecular Foundry and co-lead authors on the paper, designed and performed an experiment to combat clumping by depositing 1.5nm-diameter nickel clusters onto a 2D substrate made of boron and nitrogen engineered to host a grid of atomic-scale dimples. The nickel clusters became evenly dispersed and securely anchored to the dimples. Not only did this design prevent clumping, but the 2D substrate's thermal and chemical properties greatly improved the catalyst's overall performance by directly interacting with the nickel clusters.
"The role of the underlying surface during the cluster formation and deposition stage has been found to be critical, and may provide clues to understanding their role in other processes," said Urban.
Detailed X-ray and spectroscopy measurements, combined with theoretical calculations, revealed much about the underlying surfaces and their role in catalysis. Using tools at the Advanced Light Source at Berkeley Lab and computational modelling methods, the researchers identified changes in the physical and chemical properties of the 2D sheets while the tiny nickel clusters were deposited on them.
The team proposed that the nickel clusters occupy pristine regions of the sheets and interact with nearby edges, thus preserving the tiny size of the clusters. The tiny, stable clusters were able to facilitate the processes through which hydrogen is separated from its liquid carrier, endowing the catalyst with excellent selectivity and productivity, and ensuring a stable performance.
Calculations showed that the catalyst's size was the reason its activity was among the best ever achieved. David Prendergast, director of the Theory of Nanostructured Materials Facility at the Molecular Foundry, along with postdoctoral research assistant and co-lead author Ana Sanz-Matias, used models and computational methods to uncover the unique geometric and electronic structure of the tiny metal clusters.
Bare metal atoms, abundant on these tiny clusters, more readily attracted the liquid carrier than did larger metal particles. These exposed atoms also eased the steps of the chemical reaction that strips hydrogen from the carrier, while preventing the formation of contaminants that may clog the surface of the cluster. As a consequence, the material remained free of pollution during key steps in the hydrogen-production reaction. These catalytic and anti-contamination properties emerged from the imperfections that had been deliberately introduced to the 2D sheets and ultimately helped keep the cluster size small.
"Contamination can render possible non-precious metal catalysts unviable. Our platform here opens a new door to engineering those systems," said Urban. Future work by the Berkeley Lab team will further hone the strategy of modifying 2D substrates in ways that support tiny metal clusters, to develop even more efficient catalysts.
The CCAI says that applications for the 2021 Matt Heuertz Scholarship Program are now being accepted. The program, administered by the non-profit CCAI Finishing Education Foundation (CCAIFEF), aims at encouraging students to pursue education that can lead to a career in industrial finishing.
The foundation has reportedly awarded more than US$100,000 in scholarship funds over the past five years. Scholarship recipients also receive a free one-year CCAI student membership.
‘Attracting new young talent is crucial to the future of our industry,’ said CCAIFEF executive director, Sheila LaMothe. ‘Each year we receive applications from an outstanding pool of students that are not only pursuing studies that could likely lead to a career in industrial finishing, but many of whom are already engaged in the industry through internships, summer employment and job shadow opportunities.’
For more information go here. The deadline for submission is 15 April 2021, and the awards will be announced in June.
This story uses material from the CCAI, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier.
Hexion Inc, which makes phenolic resins for composites, has appointed Karen M Fowler as its first Director of diversity, equity and inclusion (DEI).
According to the company, Fowler will be responsible for improving the organization’s diversity, equity and inclusion, including developing and implementing a strategy to attract, retain and develop diverse talent and promote an inclusive environment.
‘Diversity and inclusion enhance creativity and innovation as team members come together with different information, opinions, and viewpoints,’ said Craig Rogerson, CEO. ‘Diversity and inclusion encourage the search for novel information and perspectives, leading to better decision making and problem solving.’
Fowler recently served as a director at the National Diversity Council and also worked at Thermo Fisher Scientific, Time Warner Cable, and The Ohio State University.
This story uses material from Hexion, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier.
GE Additive and the University of Sydney have formed a five-year agreement to improve Australia’s additive manufacturing (AM) capabilities.
Plans are to develop a 3D printing space at the Sydney Manufacturing Hub to train specialists and academics working in additive manufacturing and create small to medium manufacturing enterprises.
According to GE, the output of Australian manufacturing is estimated to reach AUS$131 billion by 2026, with ‘advanced manufacturing’ potentially growing the domestic sector by approximately AUS$30 billion over the next five years.
Professor Simon Ringer, University director of core research facilities, said that the recent COVID-19 crisis had exposed the country to vulnerabilities due to dependence on complex, ‘just-in-time’ supply chains. ‘Pre-Covid-19, a national focus on manufacturing resilience was generally regarded as a nice thought,’ he said. ‘We have long believed this needs to be a critical national priority, and Covid-19 has raised the stakes. A manufacturing renaissance is coming and for Australia to lead in this space, there must be an investment in skills.’
The organizations say that aerospace and space, the defence industry, robotics platforms, medical devices, construction, agricultural-tech, oil and gas, and mining, could all benefit from AM technology.
This story uses material from The University of Sydney, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier.
New alloys can be designed and implemented without a long lead-time in critical areas such as spinal devices, dental and craniomaxillofacial devices, as well as other load-bearing applicationsAmit Bandyopadhyay
With over half of all commercial biomedical implants containing metal, a new study by researchers at Washington State University, the Mayo Clinic, and Stanford University Medical Center has shown the value of using 3D printing to identify new alloys that improve upon metals that have been in surgical use for decades.
As reported in Materials Today [Mitra et al. Mater. Today (2020) DOI: 10.1016/j.mattod.2020.11.021], 3D printing was used to assess a range of new and more effective alloys in implants – mainly used in orthopedic, dental, fracture management, spinal and cardiovascular applications. The three main alloys are currently employed in biomedical implants: stainless steel, titanium, and cobalt–chrome were originally developed by the automotive and aerospace industries for their strength, fatigue, corrosion resistance, and not for their biological performance.
A common problem with metallic implants is metal ion hypersensitivity and a lack of favorable tissue materials interaction for faster healing. Different coatings have been used to improve the surface properties of implants, which have worked to an extent, but a lack of strong bonding with the base metal is common, which has resulted in many interfacial failures, leading to revision surgeries. This drove the multi-disciplinary team to explore how best to design new alloys specifically to improve their biocompatibility (i.e., biological performance).
Their straightforward approach based on 3D printing technology could be a game-changer, as it allows for parts to be made with complex shapes, flexible design, and the ability to customize. This could also reduce healing time and increase the lifetime of implants. As team leader Amit Bandyopadhyay told Materials Today, “New alloys can be designed and implemented without a long lead-time in critical areas such as spinal devices, dental and craniomaxillofacial devices, as well as other load-bearing applications”.
Existing implants coated with tantalum demonstrate the metal has excellent biocompatibility, with applications as a coating to enhance tissue–materials interactions. As tantalum has a very high density and a very high melting point, and is much more expensive than titanium, the addition of tantalum to titanium was tried via 3D printing. While processing tantalum is a major challenge, a titanium–tantalum alloy can be processed efficiently while keeping to a similar density. Tests showed that an alloy of 90% titanium and 10% tantalum exhibited similar biological performance as 100% tantalum, indicating that only a small fraction of tantalum would be sufficient.
The team is now looking at potential new alloys to help stop infections on implants' surfaces to minimize many painful revision surgeries, particularly for patients with bone disorders.
Leading a collaboration of institutions in the US and abroad, Princeton University's Department of Chemistry is reporting new topological properties of the magnetic pyrite cobalt disulfide (CoS2) that expand science's understanding of electrical channels in this long-investigated material.
Using angle-resolved photoelectron spectroscopy and ab-initio calculations, researchers working within the Schoop Lab at Princeton discovered the presence of Weyl nodes in bulk CoS2 that allow predictions to be made about its surface properties. The material hosts Weyl-fermions and Fermi-arc surface states within its band structure, which may allow it to serve as a platform for exotic phenomena and potentially find use in spintronic devices.
The research also settles a long-standing debate, by proving that CoS2 is not a true half-metal. A half-metal is any substance that acts as a conductor to electrons of one spin orientation but as an insulator or semiconductor to those of the opposite orientation. Although all half-metals are ferromagnetic, most ferromagnets are not half-metals. This finding that CoS2 is not a half-metal has important implications for materials and device engineering.
Leslie Schoop, assistant professor of chemistry at Princeton Chemistry, called the work "a rediscovery of new physics in an old material". Schoop and her colleagues report their findings in a paper in Science Advances.
CoS2 has been a subject of study for many decades because of its itinerant magnetism. Since the early 2000s – before topological insulators were predicted and discovered – it has also been investigated for its potential to be a half-metal. Th researchers were "happy" to put the latter discussion to rest.
Through the Schoop research, CoS2 was discovered to be a rare example of a group of magnetic topological metals proposed as agents of charge-to-spin conversion. By disentangling the bulk and surface electronic structure of CoS2, the researchers have demonstrated that there is a relationship between electronic channels in the inner material that can predict other states at its surface.
An electrical current can go through the bulk of a material or flow along its surface. Researchers found that bulk CoS2 contains objects called Weyl nodes within its structure that serve as electronic channels that can predict other states at the surface.
"The beautiful physics here is you have these Weyl nodes that demand spin-polarized surface states. These may be harvested for spintronic applications," said Schoop.
"These electronic states that only exist at the surface have chirality associated with them, and because of that chirality the electrons can also only move in certain directions. Some people think about using these chiral states in other applications. There aren't many magnetic materials where these have been found before."
Chirality refers to the property that makes an object or system distinguishable from its mirror image – i.e. not superimposable – and is an important property in many branches of science.
Schoop added that the electronic channels are polarized. This magnetism could potentially be used to manipulate CoS2: scientists could switch the magnetization direction and surface states could then be reconfigured as a response to this applied magnetic field.
"There are just a very few magnetic materials that have been measured to have such surface states, or Fermi arcs, and this is like the fourth, right? So, it's really amazing that we could actually measure and understand the spinchannels in a material that was known for so long," said Maia Vergniory from the Donostia International Physics Center in Spain, who is a co-author of the paper.
As colleagues in 2016, Schoop and Vergniory discussed investigating the material properties of CoS2, particularly whether it could be classified as a true half-metal. Their investigation went through several iterations after Schoop arrived at Princeton in 2017, and was worked on by graduate students under Schoop and under Vergniory at Donostia.
Niels Schröter, a colleague at the Paul Scherrer Institute in Switzerland and lead author of the paper, oversaw the team at the Swiss Light Source that mapped out the material Weyl nodes.
"What we wanted to measure was not just the surface electronic structure," said Schröter. "We also wanted to learn something about the bulk electronic properties, and in order to get both of these complementary pieces of information, we had to use the specialized ADRESS beamline at the Swiss Light Source to probe electrons deep in the bulk of the material."
Schröter explained how engineers might build a device down the road using CoS2. "You would put this material in contact with another material, for instance with a magnetic insulator or something like that in which you then want to create magnetic waves by running an electric current through it.
"The beauty of these topological materials is that these interfacial electrons that may be used for spin-injection, they are very robust. You cannot easily get rid of them. This is where these fields of topology and spintronics may meet, because topology is maybe a way to ensure that you have these spin-polarized interface states in contact with other magnetic materials that you would like to control with currents or fields."
"I think that this kind of rediscovery in this very old and well-studied material is very exciting, and I'm glad I have these two amazing collaborators who helped nail it down," added Schoop.
This story is adapted from material from Princeton University, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.
Are production plants – facilities consuming huge amounts of energy – doomed to the energy that comes from burning of fossil fuels? A consortium of scientists and specialists is developing technologies that will make it possible...
The Editorial Board of Nuclear Instruments and Methods, Section A (NIMA) is currently accepting nominations for the following award, and we are counting on your to help us identify potential honorees! We invite you to review the award criteria, and to nominate a worthy colleague. All nominations should be submitted via email no later than the 15th of March 2021 to Prof. Fulvio Parmigiani (chair of the scientific committee, firstname.lastname@example.org) and Prof. Bill Barletta (co-chair, email@example.com).
The prize aims to recognize and encourage outstanding experimental achievements in synchrotron radiation research with a significant component of instrument development. Particular preference will be given to the development of synchrotron radiation spectroscopies.
Rules and eligibility:
Nominations are open to scientists of all nationalities without regard to the geographical site at which the work was performed. Usually, the prize shall be awarded to one person but it may be shared if all recipients have contributed to the same accomplishment. The prize recipient should be 45 years old or younger at the time of selection. Nominations are active for two prize cycles.
Nominations are accepted from the NIMA advisory board, the NIM board of editors, synchrotron radiation facility directors as well as from scientists engaged in synchrotron radiation science. Nomination packages should include a nominating letter, at least one supporting letter, a list of five papers on which the award is based as well as a proposed citation for the award.
The award will be given at the SRI conference (Synchrotron Radiation Instrumentation conference) held in Hamburg, Germany from the 30th of August until the 3rd of September 2021 and a ceremony will be organized by the Physics Department of the Uppsala University, Sweden. (Please note that in the present context modifications to this organizations may occur due to the COVID-19 situation.)
The prize is being awarded every two years and consists of a EUR 3000 prize plus a travel allowance to the meeting at which the prize is awarded and a certificate citing the contributions made by the recipient.
At least one member of the NIM board of editors
One previous prize winner
Three to four senior scientists from the field of synchrotron radiation research
The scientific committee of the 2021 Kai Siegbahn prize is:
F. Parmigiani (Chair, Editor of NIMA, University of Trieste); W. Barletta (Co-Chair, Editor in Chief of NIMA, MIT); Prof. Dr. Yulin Chen ( University of Oxford); Prof. Dr. Hermann Dürr (University of Uppsala); Dr. Robert Schoenlein ( SLAC-LCLS- Stanford); Prof. Dr. Henry Chapman (CFEL and University of Hamburg); Dr. Elke Plönjes-Palm (FLASH, DESY); Dr. Sakura Pascarelli (European XFEL); Dr Christian Tusche (Forschungszentrum Jülich)
Airbus says that the Belgian Air Force has taken delivery of its first of seven Airbus A400M military transport aircraft.
The second A400M for Belgium will be delivered in early 2021.
‘With the delivery of this aircraft all launch customers are now equipped with the A400M,’ said Alberto Gutierrez, head of military aircraft at Airbus Defence and Space. ‘MSN106 will join Luxemburg’s aircraft in the binational unit operated jointly with Belgium. Despite challenges due to Covid-19, our teams have achieved all 10 aircraft deliveries scheduled this year, bringing the global fleet in operation to 98 aircraft.’
This story uses material from Airbus, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier.
Lockheed Martin Corporation has agreed to acquire aerospace and defense rocket engine manufacturer Aerojet Rocketdyne Holdings Inc for a total transaction value of US$4.4 billion.
Aerojet had a 2019 revenue of approximately US$2 billion and employs nearly 5000 employees in 15 primary operations sites across the United States. According to Lockheed, Aerojet Rocketdyne's propulsion systems are already a component of Lockheed Martin's supply chain and systems in its aeronautics, missiles and fire control, and space business areas.
‘Acquiring Aerojet Rocketdyne will preserve and strengthen an essential component of the domestic defense industrial base and reduce costs for our customers and the American taxpayer,’ said James Taiclet, Lockheed Martin president and CEO. ‘This transaction enhances Lockheed Martin's support of critical US and allied security missions and retains national leadership in space and hypersonic technology.’
The transaction is expected to close in the second half of 2021.
This story uses material from Lockheed, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier.
3D printing company VELO3D has formed a distribution partnership in the US with additive manufacturing (AM) sales specialist GoEngineer.
GoEngineer also supplies Stratasys and Solidworks 3D printing products in the country.
‘We are pleased to partner with VELO3D to help manufacturing companies across the US produce mission-critical parts for industrial use,’ said Ken Clayton, CEO of GoEngineer. ‘VELO3D delivers breakthrough SupportFree technology for the design and manufacturing of metal parts that are not hindered by geometric constraints nor compromised by part quality. Metal additive manufacturing is an important piece to GoEngineer’s portfolio and we are excited to help our customers differentiate themselves even more.’
This story uses material from VELO3D, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier.
A hybrid structure based inspired by the skin color-changing talents of cephalopods has been developed by researchers in the USA. The material is comprised of a rigid film with a low thermal emissivity and a substrate with a high thermal emissivity, with a stretchable heater that can generate microscopic cracks in the surface. The thermal emissivity can be changed reversibly and instantaneously. Such a biomimetic material might be useful in motion sensing, specifically finger motion on a touch screen, in information encryption, multiplexing displays, and thermal, infrared, camouflage.
Earlier work on creating tuneable thermal emissive materials of this kind have often been limited by low response rates, high working temperatures, or simply being difficult to fabricate. Songshan Zeng of the University of Connecticut in Storrs, and colleagues there and at Dartmouth College in Hanover, New Hampshire, turned to biological systems as inspiration they hoped would circumvent these and other problems. [Zeng, S. et al., Mater. Today (2020); DOI: j.mattod.2020.12.001]
Cephalopods, such as cuttlefish, squid, and octopuses, have sophisticated systems in their skin that allow them to change color, generate dynamic patterns, and produce surface-mimicking camouflage very effectively and efficiently. There are usually two types of functional skin cells in the active layer that each have different optical properties. The first type of cells is the iridocytes, which contain periodic protein building blocks and spaces. This presents a Bragg stacking geometry for actively controlling the scattering, refraction, and reflection of light. The second class is the chromatophores. These contain pigments surrounded by tissues that can block or reveal the underlying colors.
Other researchers have focused on mimicking the iridocytes with some degree of success. Commonly, however, there are issues with this approach such as low response rates. Zeng and colleagues have looked at mechanical strain as an alternative approach that nevertheless mimics the mechanical changes in the cephalopod skin, and as such takes its lead from the way in which chromatophores work to hide and reveal pigments using a mechanical mechanism.
The team's system has a mirror chrome coating containing thin aluminum ?akes) - this is the low emissivity layer. This is on top of a polyvinyl alcohol (PVA)/laponite composite transition layer bonded to a stretchable substrate - the high emissivity layer. The stretchable heater layer is made of a serpentine patterned conductive thread sandwiched by stretchable double-sided tape beneath the substrate. Applying strain generates microscopic cracks. When these microscopic cracks are opened or closed they reveal or hide the high emissivity layer underlying the film.
The team has demonstrated how this composite film might be used as a wearable finger motion sensor. They have also demonstrated a mechanical responsive information encryption device. The same composite film also has potential in the construction of thermographic display arrays and dynamic thermal camouflage that can adapt to a changing thermal environment to hide something from an infrared camera or detector, for instance.
"This work is expected to facilitate the creation of the next-generation thermal modulation devices with autonomous, on-demand, and wide-range control," the team concludes.
David Bradley also writes at Sciencebase Science Blog and tweets @sciencebase. His popular science book Deceived Wisdom is now available.
Treating neurodegenerative diseases like Alzheimer’s and Parkinson’s is challenging because of the presence of the blood brain barrier, which effectively blocks potentially harmful agents from reaching the brain. Nanoparticles (NPs) made of the biocompatible polymers polylactic acid (PLA) and polyethylene glycol (PEG) can limit clearance by the immune system and access the brain, according to scientists [Rabanel et al., Journal of Controlled Release328 (2020) 679-695, https://doi.org/10.1016/j.jconrel.2020.09.042].
“The blood-brain barrier filters out harmful substances to prevent them reaching the brain. But this same barrier also blocks the passage of drugs,” explains Charles Ramassamy of INRS in Canada, who led the study. “Typically, high doses are required to get a small amount of a drug into the brain. What remains in the bloodstream can induce side effects.”
Polymeric NPs are a promising candidate for all types of drug delivery but could have unique advantages for overcoming the blood brain barrier. Ramassamy and his team used a simple synthetic approach to create particles with a PLA core and a shell of PEG chains. The size of the particle, as well as the length and density of PEG chains can be varied, allowing the researchers to select combinations with the most promising properties, which were then tested in vivo using zebrafish.
“The zebrafish is a good model for the blood brain barrier [because it] retains many of the features of mammals,” explains first author of the study, Jean-Michel Rabanel. “The great advantage is that the biodistribution of NPs can be imaged in real time.”
The researchers’ observations confirm that particles cross the blood brain barrier through active cellular processes known as endocytosis and exocytosis. In zebrafish, the team found that the NPs are also translocated across vascular walls and end up in specific regions, including the brain.
“A layer of PEG… makes [the NPs] invisible to the immune system, so their half-life in the bloodstream is longer,” explains Ramassamy.
The length of PEG chains on the surface of the NPs seems to influence the endocytosis pathway, while the density of chains has an effect on the interaction of NPs with vascular endothelial cells.
“Drug nanotransporters have numerous advantages to target toxic or degradation-sensitive drugs across cell barriers,” points out Rabanel. “[Our results] could have implications for blood brain barrier particle adhesion and translocation to the brain, but we still need to optimize transport efficiency and understand the interactions between NPs and the vascular endothelium.”
The team now plans to explore other surface parameters and, ultimately, test NPs in other animal models, particularly mammals that are closer to humans.
Chemical company INEOS has become part of the Mercedes-AMG Petronas Formula One team as a one third equal shareholder alongside Daimler and Austrian investor Toto Wolff.
The INEOS one-third stake in the team will be in addition to its existing role as principal partner, the company said. Daimler will reduce its current 60% shareholding and Toto Wolff increase his current 30%, in order to create three equal partners in the company.
‘Big challenges are a core part of our mindset at INEOS and our involvement across a number of different sports demonstrates that we always aim for the very best,’ said Sir Jim Ratcliffe, chairman of INEOS. ‘This is a unique opportunity to make a financial investment in a team at the very top of its game, but which still has rich potential to grow in the future.’
This story uses material from INEOS, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier.
3D printing company Renishaw plans to strengthen its presence in the EU, following the completion of Brexit.
This includes new and expanded logistics centers in Ireland and Germany, an increase in stock levels throughout the EU region and converting local offices into independent subsidiaries.
Transactions and deliveries could then take place via these local subsidiaries instead of through the UK, the company said.
‘To mitigate against the possible impacts of Brexit, we have been focused on ensuring that our customers within the EU are able to receive optimal support from our local offices and that all transactions, including deliveries of goods, are as simple as possible,’ said Rainer Lotz, president of Renishaw's EMEA region.
This story uses material from Renishaw, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier.
DMG MORI, which makes cutting tools and additive manufacturing (AM) machines, has selected a melt pool monitoring system from Sigma Labs for its range of metal 3D printers.
DMG’s LASERTEC SLM machines will be interfaced with PrintRite3D Ready, Sigma says.
‘Covid-19 has demonstrated the importance of digital readiness, which allows business and life to continue as usual – as much as possible – during pandemics,’ said The World Economic Forum, cited in a press release. ‘Building the necessary infrastructure to support a digitized world and stay current in the latest technology will be essential for any business or country to remain competitive in a post-Covid-19 world.’
This story uses material from Sigma, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier.
The technique allows one to effectively investigate the evolution of physical properties of 2D materials with respect to twist angles, including low-frequency interlayer modes, band structure, optical and electrical propertiesYaping Yang
An international team from the University of Manchester have demonstrated a new way to fine tune the angle, or “twist”, between atom-thin materials in van der Waals heterostructures, a breakthrough that helps control the interlayer twist angle to offer a range of possible applications. The method was shown to exhibit in situ dynamical rotation and manipulation of 2D materials that were located on top of each other to form van der Waals heterostructures, nanoscale devices that offer unusual properties and interesting phenomena.
With the tuning of the twist angle to control the topology and electron interactions in 2D materials being increasingly investigated, this technique, reported in Science Advances [Yang et al. Sci Adv. (2020) DOI: 10.1126/sciadv.abd3655], enables twisted van der Waals heterostructures with dynamically tuneable optical, mechanical and electronic properties. Twisting together layers of 2D crystals results in a moiré pattern where lattices of the parent 2D crystals form a superlattice, which would bring precise positioning, rotation and manipulation, and also changes in the behavior of electrons in the system.
The team managed to fabricate heterostructures where graphene is perfectly aligned with both top and bottom encapsulating layers of hexagonal boron nitride, producing double moiré superlattices at the two interfaces. A glass slide with a droplet of polydimethylsiloxane (PDMS) was used as a manipulator, which is cured and naturally shaped into a hemisphere geometry, while also depositing an epitaxial polymethyl methacrylate (PMMA) patch on top of a target 2D crystal.
Manipulating the target flakes involved lowering the polymer gel handle to bring the PDMS hemisphere into contact with the PMMA patch. It was then straightforward to move or rotate the target 2D crystals on the surface of the bottom flake, made possible by the superlubricity between the two crystalline structures.
The method allows for continuous tuning of the twist angle between the layers even after heterostructure assembly. It is possible to design the patch into any shape, typically taking the geometry that fits the target flake. This patch has a key role in the manipulation, with the contact area of the polymer gel manipulator being limited to the patterned shape of the epitaxial polymer layer, allowing precise control of the manipulation and a much greater controlling force to be applied.
This approach is non-destructive and can manipulate flakes irrespective of their thickness. As main author Yaping Yang said, “The technique … allows one to effectively investigate the evolution of physical properties of 2D materials with respect to twist angles, including low-frequency interlayer modes, band structure, optical and electrical properties”. The team are now exploring how in twistronics the topology and electron interactions in twisted 2D material system are highly dependent on the twist angles.
Two recent studies involving researchers at the University of Pennsylvania demonstrate how to fabricate materials with single atom-sized pores that can be used for liquid and gas filtration. This regime of 'zero dimensional' pores has a broad range of future applications, from water and gas purification to energy harvesting.
The first study, reported in a paper in ACS Nano and led by graduate student Jothi Priyanka Thiruraman, postdoc Paul Masih Das and professor Marija Drndic at the University of Pennsylvania, demonstrates the ionic transport properties of these pores, which show promise for applications in water purification and desalination. They could also be used to create artificial pores that mimic ion channels in biology.
The second study, reported in a paper in Science Advances, demonstrates how helium gas flows through these pores. This work was conducted by experimentalists at the University of Pennsylvania and in Radha Boya’s group at the University of Manchester in the UK, with theoretical modelling by researchers at Shahid Rajaee University in Iran and the University of Antwerp in Belgium.
Researchers in the Drndic lab have expertise in making atomically thin materials and devices that are dotted with nanopores. Wanting to scale these pores down even further, Thiruraman and Masih Das previously developed a method for making 'angstrom-size' pores, which are small enough to only allow single atoms and small molecules to pass through.
While this work was instrumental in demonstrating that these types of pores could be made, fabricating devices for use outside of controlled, experimental settings remained a challenge. “There’s a lot of device physics between finding something in a lab and creating a usable membrane,” says Drndic.
To get from fundamental discovery to a working device, Thiruraman and Masih Das synthesized materials with angstrom-sized pores while making systematic changes to their previous method to try to create a more resilient material. Their method involves first growing a monolayer of tungsten disulphide by chemical vapor deposition. Then, they transfer this 2D material to a transmission electron microscope grid and expose it to either a focused electron or ion beam, which punches out single atoms from the monolayer to leave behind tiny, atom-sized pores.
Using a systematic approach to testing and modifying this fabrication process, the researchers were able to refine their method and develop a prototype that could be tested in more 'real-world' conditions than was previously possible. “Instead of just studying the material inside of an electron microscope, how do you make an actual device? That’s something that took us a long time to figure out,” says Masih Das. “We used our knowledge to make devices that you can measure ionic or gas transport on, and that was the big difficulty.”
“Being able to reach that atomic scale experimentally, and to have the imaging of that structure with precision so you can be more confident it’s a pore of that size and shape, was a challenge,” adds Drndic. “That came with the advancement of the technology as well as our own methodology, and what is novel here is to integrate this into a device that you can actually take out, transport across the ocean to Manchester if you wish and measure.”
Prototypes in hand, the researchers ran experiments using salt water to see how effective the material was at removing salt ions from the water, reporting their findings in the ACS Nano paper. “When you shrink the system to a single atom, we see that it’s independent of the salt water that you are putting in, so the hole does not seem to distinguish between what ion is going through,” says Thiruraman. “For salt ions, we are able to see with just a single hole a very standard saturated current level because the hole is so small, and its size dominates the conduction behavior.”
Then, to see if the material could also filter gases, they collaborated with researchers at the University of Manchester who had previously developed a way to measure gas transport in nanoscale devices. This work, reported in the Science Advances paper, shows that their device can also be used to move helium atoms through atomic apertures and is the first-ever measurement of its kind.
“We were very surprised to get any results at all because the holes are tiny,” Thiruraman says. “No one’s ever measured something like this, so just getting a helium atom to pass and detect through atomic apertures was very cool.”
The opportunities for potential applications are wide-ranging, from water desalination to energy harvesting to measuring small molecules such as hormones and pharmaceuticals. “But of course, at this fundamental level, we’re trying to see how these materials are robust at the atomic scale,” says Drndic.
The researchers are now interested in continuing their fundamental investigations into this material to better understand if the pores change over time and if layering individual sheets could change the material’s properties. They also want to explore how the geometric shapes of the pores themselves influence transport mechanisms and device properties.
Composites specialist Airborne is collaborating with a software company to create a digital interface for automated kitting.
According to the company it plans to integrate its automated kitting solution and JETCAM’s CrossTrack composite material tracking software.
Airborne says that this will make it easier to exchange data between the two systems as plies are unloaded from the cutting table and then automatically sorted into ordered kits by the Airborne’s kitting system. As the operator loads each ply to the kitting machine it is scanned and its shape identified, along with its stacking order. The robot sorts, sequences and stacks all subsequent plies until the kit is complete, automatically updating its status within CrossTrack without any user input. When the completed kit leaves the buffer its location status is updated, automating the process from cutting through to moving onto layup.
‘Many companies move from producing static single kit nests to using nesting software, creating highly efficient dynamic nests, often containing multiple kits,’ said Martin Bailey, General Manager at JETCAM International. ‘However, this leads to bottlenecks at the cutter as staff try to unload and sort plies into kits, often removing some or all of the material savings made.’
This story uses material from Airborne, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier.
COMAC subsidiary SAMC, AVIC Supply and GKN Aerospace have signed a strategic joint venture (JV) agreement to make composite and metal aerostructures in Jingjiang, China.
This will reportedly involve building an 80,000m2 facility, with production scheduled to begin in Q4 2021. By the mid-2020s, the workforce is expected to grow to 1,000 people, GKN said.
The company also plans to open a separate 20,000 m2 site nearby, focusing on making transparencies for the commercial market.
‘The establishment of the first aerostructures JV and the upcoming opening of the transparencies facility in Jingjiang, Jiangsu Province, China are exciting milestones,’ said John Pritchard, president civil aerospace at GKN. ‘We are excited to be part of the growth of the commercial aerospace industry in China.’
This story uses material from GKN, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier.
Proto Labs has appointed Robert Bodor to succeed Vicki Holt as the company’s president and CEO.
Holt is reportedly retiring after leading the company for the past seven years.
‘Since joining the company, Rob has held a variety of leadership roles, including overseeing our largest region since 2015,’ she said. He has more than doubled the revenue of the Americas’ business during his tenure and played an instrumental role in expanding the company’s services into 3D printing and sheet metal fabrication. Rob is a very strategic business leader and a great leader of people.’
Bodor previously served as Protolabs vice president and general manager of the Americas. He also held roles as chief technology officer and leader of the company’s business development and product development functions.
This story uses material from Protolabswith editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier.
This film can be further implemented to wearable devices in the near future, since the wearable device will be continuously flexed (cracked) during applicationYu-Chi Chang
A self-healing gelatin-based film that can repair itself numerous times while maintaining the electronic signals required to access data in a device has been demonstrated by a group from the National Cheng Kung University in Taiwan. The film offers useful properties for overcoming fragility problems – such as cracks in the casing, or fractures develop in the material that stores data – in touchscreen and flexible display devices, and could also find uses in advanced robotics and assisted health technologies.
Gelatin has already been employed in new electronic devices due it its translucency, flexibility, water solubility and biodegradability. It is also easily available and safe, and can be easily stored in an ambient atmosphere for long periods without deterioration. However, damaged gelatin films tend not to restore quickly, while other self-repairing films usually work only once, and can contain harmful agents. However, as reported in ACS Applied Polymer Materials [Chang et al. ACS Appl. Polym. Mater. (2020) DOI: 10.1021/acsapm.0c01119], this research investigated if it was possible to develop a repeatedly self-healing gelatin-based film that could mend cracks quickly while preserving electrical functionality.
The team had previously applied gelatin to resistive memory, showing excellent stability, and developed fully transparent resistive memory, highly uniform resistive memory elements and full biological properties with decomposed electronic components. While gelatin shows promise for making flexible resistive memory components, their previous work had shown that continuous deflection made the gelatin irregular and caused cracks in the film, resulting in rapid loss in the performance for resistive memory devices.
Here, glucose was combined with gelatin to produce a flexible film that was then placed in a conductive material to simulate an electronic device. When this device was bent, breaks in the gelatin-glucose film disappeared within three hours at room temperature, and also within 10 minutes when the device was heated to 600C. The glucose-based gelatin was also able to send out an electrical signal after many rounds of damage and repair, with the film's electrical performance also surprisingly being improved.
When supplemented by temperature from the human body, the film could possibly be used in wearable components. As group leader Yu-Chi Chang told Materials Today, “This film can be further implemented to wearable devices in the near future, since the wearable device will be continuously flexed (cracked) during application”.
With the method for producing this film being relatively straightforward, the researchers expect many applications in electronic components and biomedicine. They are continuing apply the self-healing film to different electronic components, such as sensing components, and to complete self-healing circuits without the need for a vacuum process.
Superhard materials are in high demand by industry, for use in applications ranging from energy production to aerospace, but finding suitable new materials has largely been a matter of trial and error, based on classical hard materials such as diamonds. Until now.
In a paper in Advanced Materials, researchers from the University of Houston (UH) and Manhattan College report a machine-learning model that can accurately predict the hardness of new materials, allowing scientists to more readily find compounds suitable for use in a variety of applications.
Materials that are superhard – defined as those with a hardness value exceeding 40 gigapascals on the Vickers scale, meaning it would take more than 40 gigapascals of pressure to leave an indentation on the material's surface – are rare.
"That makes identifying new materials challenging," said Jakoah Brgoch, associate professor of chemistry at UH and corresponding author of the paper. "That is why materials like synthetic diamond are still used even though they are challenging and expensive to make."
One of the complicating factors is that the hardness of a material may vary depending on the amount of pressure exerted, known as load dependence. That makes testing a material experimentally complex and ensures that computational modeling is currently almost impossible.
The model reported by the researchers overcomes these difficulties by predicting the load-dependent Vickers hardness based solely on the chemical composition of the material. The researchers report finding more than 10 new stable borocarbide phases that show promise; work is now underway to design and produce the materials so they can be tested in the lab.
Based on the model's reported accuracy, the odds are good. Researchers reported its accuracy at 97%.
First author Ziyan Zhang, a doctoral student at UH, said the database built to train the algorithm is based on data involving 560 different compounds, each yielding several data points. Finding the data to build a representative dataset required poring over hundreds of published academic papers.
"All good machine learning projects start with a good dataset," said Brgoch, who is also a principal investigator with the Texas Center for Superconductivity at UH. "The true success is largely the development of this dataset."
Researchers have traditionally used machine learning to predict a single variable of hardness, Brgoch said, but that doesn't account for the complexities of a property like load dependence, which he said still isn't well understood. That makes machine learning a good tool, despite earlier limitations.
"A machine learning system doesn't need to understand the physics," he said. "It just analyzes the training data and makes new predictions based on statistics."
Machine learning does have limitations, though. "The idea of using machine learning isn't to say, 'Here is the next greatest material', but to help guide our experimental search," Brgoch said. "It tells you where you should look."
This story is adapted from material from the University of Houston, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.
A recent study conducted by Stanford University recognized several members from the Editorial Boards of the two journals affiliated with the European Ceramic Society, Journal of the European Ceramic Society and Open Ceramics, as the most-cited world researchers in the field of Materials Science.
Looking at several indicators, the study analyzed data from 1996 through 2019, covering ~7 million scientists in 22 major fields ranging from chemistry to engineering to economics and business.
Please find the list of our editors below:
Professor Richard Todd
University of Oxford, Department of Materials, Oxford, United Kingdom
Professor Paolo Colombo
University of Padova, Department Industrial Engineering, Padova, Italy
Professor Jon Binner
University of Birmingham, Birmingham, United Kingdom
Professor Vincenzo Buscaglia
Institute of Condensed Matter Chemistry and Technologies for Energy, National Research Council, Genoa, Italy
Professor Jérôme Chevalier
National Institute of Applied Sciences of Lyon, Villeurbanne, France
Professor Laura Montanaro
Polytechnic of Turin, Department of Applied Science and Technology, Torino, Italy
Professor Rodrigo Moreno
Institute of Ceramics and Glass, Madrid, Spain
Professor Eduardo Saiz
Imperial College London, London, United Kingdom
Professor Robert Vaßen
Julich Research Centre, Institute of Energy and Climate Research, Julich, Germany
Professor Gerard Vignoles
Laboratory of Thermostructural Composites, Université de Bordeaux - CNRS - CEA - Safran Ceram, Pessac, France
Professor Jozef Vleugels
KU Leuven, Department of Materials Science, Leuven, Belgium
Professor Robert Freer
The University of Manchester, School of Materials, Manchester, United Kingdom
Professor Christian Rüssel
Friedrich Schiller University, Jena, Germany
Professor Albert Tarancón
Catalan Institution for Research and Advanced Studies, Barcelona, Spain