Engineering and Technology Updates
New Technology to Reduce Potholes
Researchers have developed new “intelligent compaction” technology, which integrates into a road roller and can assess in real-time the quality of road base compaction. Improved road construction can reduce potholes and maintenance costs, and lead to safer, more resilient roads. Months of heavy rain and floods have highlighted the importance of road quality, with poor construction leading to potholes and road subsidence. This not only causes tyre blowouts and structural damage to cars and trucks, but also increases the chance of serious accidents. The innovative machine-learning technique, which processes data from a sensor attached to construction roller, was developed by a research team from the University of Technology Sydney. They developed an advanced computer model that incorporates machine-learning and big data from construction sites to predict the stiffness of compacted soil with a high degree of accuracy in a fraction of second, so roller operators can make adjustments. Roads are made up of three or more layers, which are rolled and compacted. The subgrade layer is usually soil, followed by natural materials such as crushed rock, and then asphalt or concrete on top. The variable nature of soil and moisture conditions can result in under or over-compacted material. The compaction needs to be ‘just right’ to provide the correct structural integrity and strength. Over-compaction can break down the material and change its composition, and under-compaction can lead to uneven settlement. The research suggests the application of this technology could help build longer-lasting roads that can better withstand severe weather conditions. The team is now looking to test the new technology onsite for various ground and roller conditions for road, railway and dam construction projects, and explore techniques to measure density and moisture content of the compacted soil in real-time during construction.
Revolutionary AI System Learns Concepts Shared Across Video, Audio, and Text
A machine-learning model can identify the action in a video clip and label it, without the help of humans. Humans observe the world through a combination of different modalities, like vision, hearing, and our understanding of language. Machines, on the other hand, interpret the world through data that algorithms can process. So, when a machine “sees” a photo, it must encode that photo into data it can use to perform a task like image classification. This process becomes more complicated when inputs come in multiple formats, like videos, audio clips, and images. Researchers at the Computer Science and Artificial Intelligence Laboratory (CSAIL) have developed an artificial intelligence (AI) technique that allows machines to learn concepts shared between different modalities such as videos, audio clips, and images. The AI system can learn that a baby crying in a video is related to the spoken word “crying” in an audio clip, for example, and use this knowledge to identify and label actions in a video. The technique performs better than other machine-learning methods at cross-modal retrieval tasks, where data in one format (e.g. video) must be matched with a query in another format (e.g. spoken language). It also allows users to see the reasoning behind the machine’s decision-making. In the future, this technique could potentially be used to help robots learn about the world through perception in a way similar to humans. MIT researchers developed a machine learning technique that learns to represent data in a way that captures concepts which are shared between visual and audio modalities. Their model can identify where certain action is taking place in a video and label it. The researchers developed an artificial intelligence technique that learns to represent data in a way that captures concepts which are shared between visual and audio modalities. For instance, their method can learn that the action of a baby crying in a video is related to the spoken word “crying” in an audio clip. Using this knowledge, their machine-learning model can identify where a certain action is taking place in a video and label it. It performs better than other machine-learning methods at cross-modal retrieval tasks, which involve finding a piece of data, like a video, that matches a user’s query given in another form, like spoken language. Their model also makes it easier for users to see why the machine thinks the video it retrieved matches their query. This technique could someday be utilized to help robots learn about concepts in the world through perception, more like the way humans do. The researchers’ focus their work on representation learning, which is a form of machine learning that seeks to transform input data to make it easier to perform a task like classification or prediction. The representation learning model takes raw data, such as videos and their corresponding text captions, and encodes them by extracting features, or observations about objects and actions in the video. Then it maps those data points in a grid, known as an embedding space. The model clusters similar data together as single points in the grid. Each of these data points, or vectors, is represented by an individual word. For instance, a video clip of a person juggling might be mapped to a vector labeled “juggling.” The researchers constrain the model, so it can only use 1,000 words to label vectors. The model can decide which actions or concepts it wants to encode into a single vector, but it can only use 1,000 vectors. The model chooses the words it thinks best represent the data. Rather than encoding data from different modalities onto separate grids, their method employs a shared embedding space where two modalities can be encoded together. This enables the model to learn the relationship between representations from two modalities, like video that shows a person juggling and an audio recording of someone saying “juggling.” To help the system process data from multiple modalities, they designed an algorithm that guides the machine to encode similar concepts into the same vector. They tested the model on cross-modal retrieval tasks using three datasets: a video-text dataset with video clips and text captions, a video-audio dataset with video clips and spoken audio captions, and an image-audio dataset with images and spoken audio captions. For example, in the video-audio dataset, the model chose 1,000 words to represent the actions in the videos. Then, when the researchers fed it audio queries, the model tried to find the clip that best matched those spoken words. Not only was their technique more likely to find better matches than the models they compared it to, it is also easier to understand.
A Precision Arm for Miniature Robots
A single robot can be used to carry out a variety of tasks. Until today, miniature systems that transport miniscule amounts of liquid through fine capillaries have had little association with such robots. eveloped by researchers as an aid for laboratory analysis, such systems are known as microfluidics or lab-on-a-chip and generally make use of external pumps to move the liquid through the chips. To date, such systems have been difficult to automate, and the chips have had to be custom-designed and manufactured for each specific application. Scientists at ETH are now combining conventional robotics and microfluidics. They have developed a device that uses ultrasound and can be attached to a robotic arm. It is suitable for performing a wide range of tasks in microrobotic and microfluidic applications and can also be used to automate such applications. The device comprises a thin, pointed glass needle and a piezoelectric transducer that causes the needle to oscillate. Similar transducers are used in loudspeakers, ultrasound imaging and professional dental cleaning equipment. The ETH researchers can vary the oscillation frequency of their glass needle. By dipping the needle into a liquid, they create a three-dimensional pattern composed of multiple vortices. Since this pattern depends on the oscillation frequency, it can be controlled accordingly. The researchers were able to use this to demonstrate several applications. First, they were able to mix tiny droplets of highly viscous liquids. “The more viscous liquids are, the more difficult it is to mix them,” a researcher explains. “However, our method succeeds in doing this because it allows us to not only create a single vortex, but to also efficiently mix the liquids using a complex three-dimensional pattern composed of multiple strong vortices.” Second, the scientists were able to pump fluids through a mini-channel system by creating a specific pattern of vortices and placing the oscillating glass needle close to the channel wall. Third, they succeeded in using their robot-assisted acoustic device to trap fine particles present in the fluid. This works because a particle’s size determines its reaction to the sound waves. Relatively large particles move towards the oscillating glass needle, where they accumulate. The researchers demonstrated how this method can capture not only inanimate particles but also fish embryos. They believe it should also be capable of capturing biological cells in the fluid. “In the past, manipulating microscopic particles in three dimensions was always challenging. Our microrobotic arm makes it easy,” the researcher says. “Until now, advancements in large, conventional robotics and microfluidic applications have been made separately,” he says. “Our work helps to bring the two approaches together.” As a result, future microfluidic systems could be designed similarly to today’s robotic systems. An appropriately programmed single device would be able to handle a variety of tasks. “Mixing and pumping liquids and trapping particles — we can do it all with one device,” Ahmed says. This means tomorrow’s microfluidic chips will no longer have to be custom-developed for each specific application. The researchers would next like to combine several glass needles to create even more complex vortex patterns in liquids. In addition to laboratory analysis, other applications envisaged are for microrobotic arms, such as sorting tiny objects. The arms could conceivably also be used in biotechnology as a way of introducing DNA into individual cells. It should ultimately be possible to employ them in additive manufacturing and 3D printing.
Simple method destroys dangerous ‘forever chemicals,’ making water safe
If you’re despairing at recent reports that Earth’s water sources have been thoroughly infested with hazardous human-made chemicals called PFAS that can last for thousands of years, making even rainwater unsafe to drink, there’s a spot of good news. Chemists at UCLA and Northwestern University have developed a simple way to break down almost a dozen types of these nearly indestructible “forever chemicals” at relatively low temperatures with no harmful byproducts. The researchers show that in water heated to just 176 to 248 degrees Fahrenheit, common, inexpensive solvents and reagents severed molecular bonds in PFAS that are among the strongest known and initiated a chemical reaction that “gradually nibbled away at the molecule” until it was gone, said UCLA distinguished researcher. The simple technology, the comparatively low temperatures and the lack of harmful byproducts mean there is no limit to how much water can be processed at once, researchers added. The technology could eventually make it easier for water treatment plants to remove PFAS from drinking water. Per- and polyfluoroalkyl substances — PFAS for short — are a class of around 12,000 synthetic chemicals that have been used since the 1940s in nonstick cookware, waterproof makeup, shampoos, electronics, food packaging and countless other products. They contain a bond between carbon and fluorine atoms that nothing in nature can break. When these chemicals leach into the environment through manufacturing or everyday product use, they become part of the Earth’s water cycle. Over the past 70 years, PFAS have contaminated virtually every drop of water on the planet, and their strong carbon-fluorine bond allows them to pass through most water treatment systems completely unharmed. They can accumulate in the tissues of people and animals over time and cause harm in ways that scientists are just beginning to understand. Certain cancers and thyroid diseases, for example, are associated with PFAS. For these reasons, finding ways to remove PFAS from water has become particularly urgent. Scientists are experimenting with many remediation technologies, but most of them require extremely high temperatures, special chemicals or ultraviolet light and sometimes produce byproducts that are also harmful and require additional steps to remove. A Northwestern chemistry professor et al noticed that while PFAS molecules contain a long “tail” of stubborn carbon-fluorine bonds, their “head” group often contains charged oxygen atoms, which react strongly with other molecules. Their team built a chemical guillotine by heating the PFAS in water with dimethyl sulfoxide, also known as DMSO, and sodium hydroxide, or lye, which lopped off the head and left behind an exposed, reactive tail. “That triggered all these reactions, and it started spitting out fluorine atoms from these compounds to form fluoride, which is the safest form of fluorine,” they said. “Although carbon-fluorine bonds are super-strong, that charged head group is the Achilles’ heel.” The simulations also showed the only byproducts should be fluoride — often added to drinking water to prevent tooth decay — carbon dioxide and formic acid, which is not harmful. “Quantum mechanics is the mathematical method that simulates all of chemistry, but only in the last decade have we been able to take on large mechanistic problems like this, evaluating all the possibilities and determining which one can happen at the observed rate” they said. The current work degraded 10 types of perfluoroalkyl carboxylic acids (PFCAs) and perfluoroalkyl ether carboxylic acids (PFECAs), including perfluorooctanoic acid (PFOA). The researchers believe their method will work for most PFAS that contain carboxylic acids and hope it will help identify weak spots in other classes of PFAS. They hope these encouraging results will lead to further research that tests methods for eradicating the thousands of other types of PFAS.
Lithium-Sulfur Batteries Are One Step Closer to Powering the Future
With a new design, lithium-sulfur batteries could reach their full potential. Batteries are everywhere in daily life, from cell phones and smart watches to the increasing number of electric vehicles. Most of these devices use well-known batteries-lithium-ion battery technology. And while lithium-ion batteries have come a long way since they were first introduced, they have some familiar drawbacks as well, such as short lifetimes, overheating and supply chain challenges for certain raw materials. Scientists at the U.S. Department of Energy’s (DOE) Argonne National Laboratory are researching solutions to these issues by testing new materials in battery construction. One such material is sulfur. Sulfur is extremely abundant and cost effective and can hold more energy than traditional ion-based batteries. In a new study, researchers advanced sulfur-based battery research by creating a layer within the battery that adds energy storage capacity while nearly eliminating a traditional problem with sulfur batteries that caused corrosion. “These results demonstrate that a redox-active interlayer could have a huge impact on Li-S battery development. We’re one step closer to seeing this technology in our everyday lives” said scientists. A promising battery design pairs a sulfur-containing positive electrode (cathode) with a lithium metal negative electrode (anode). In between those components is the electrolyte, or the substance that allows ions to pass between the two ends of the battery. Early lithium-sulfur (Li-S) batteries did not perform well because sulfur species (polysulfides) dissolved into the electrolyte, causing its corrosion. This polysulfide shuttling effect negatively impacts battery life and lowers the number of times the battery can be recharged. To prevent this polysulfide shuttling, previous researchers tried placing a redox-inactive interlayer between the cathode and anode. The term “redox-inactive” means the material does not undergo reactions like those in an electrode. But this protective interlayer is heavy and dense, reducing energy storage capacity per unit weight for the battery. It also does not adequately reduce shuttling. This has proved a major barrier to the commercialization of Li-S batteries. To address this, researchers developed and tested a porous sulfur-containing interlayer. Tests in the laboratory showed initial capacity about three times higher in Li-S cells with this active, as opposed to inactive, interlayer. More impressively, the cells with the active interlayer maintained high capacity over 700 charge-discharge cycles. To further study the redox-active layer, the team conducted experiments at the 17-BM beamline of Argonne’s Advanced Photon Source (APS), a DOE Office of Science user facility. The data gathered from exposing cells with this layer to X-ray beams allowed the team to ascertain the interlayer’s benefits. The data confirmed that a redox-active interlayer can reduce shuttling, reduce detrimental reactions within the battery and increase the battery’s capacity to hold more charge and last for more cycles.
A Cheaper and Greener Internet of Things with No Wires Attached
Emerging forms of thin-film device technologies that rely on alternative semiconductor materials, such as printable organics, nanocarbon allotropes, and metal oxides, could contribute to a more economically and environmentally sustainable internet of things (IoT), a KAUST-led international team suggests. The IoT is set to have a major impact on daily life and many industries. It connects and facilitates data exchange between a multitude of smart objects of various shape and size — such as remote-controlled home security systems, self-driving cars equipped with sensors that detect obstacles on the road, and temperature-controlled factory equipment — over the internet and other sensing and communications networks. This burgeoning hypernetwork is projected to reach trillions of devices by next decade, boosting the number of sensor nodes deployed in its platforms. Current approaches used to power sensor nodes rely on battery technology, but batteries need regular replacement, which is costly and environmentally harmful over time. Also, the current global production of lithium for battery materials may not keep up with the increasing energy demand from the swelling number of sensors. Wirelessly powered sensor nodes could help achieve a sustainable IoT by drawing energy from the environment using so-called energy harvesters, such as photovoltaic cells and radio-frequency (RF) energy harvesters, among other technologies. Large-area electronics could be key in enabling these power sources. KAUST researchers assessed the viability of various large-area electronic technologies and their potential to deliver ecofriendly, wirelessly powered IoT sensors. Large-area electronics have recently emerged as an appealing alternative to conventional silicon-based technologies thanks to significant progress in solution-based processing, which has made devices and circuits easier to print on flexible, large-area substrates. They can be produced at low temperatures and on biodegradable substrates such as paper, which makes them more ecofriendly than their silicon-based counterparts. Over the years, the team has developed a range of RF electronic components, including metal-oxide and organic polymer-based semiconductor devices known as Schottky diodes. These devices are crucial components in wireless energy harvesters and ultimately dictate the performance and cost of the sensor nodes. Key contributions from the KAUST team include scalable methods for manufacturing RF diodes to harvest energy reaching the 5G/6G frequency range. Such technologies provide the needed building blocks toward a more sustainable way to power the billions of sensor nodes in the near future. The team is investigating the monolithic integration of these low-power devices with antenna and sensors to showcase their true potential.
ISRO operates cryo engine CE-20 at high thrust for 650 seconds
The Indian Space Research Organisation recently said the CE-20 — a cryogenic rocket engine developed by the Liquid Propulsion Systems Centre (LPSC) — was successfully operated with a thrust level of 22t for a long duration of 650 seconds on December 23, 2022. The activity was carried out at the Cryogenic Main Engine & Stage Test Facility of ISRO Propulsion Complex (IPRC) in Mahendragiri, Tamil Nadu. “With this, the engine qualification for 20t thrust level is also successfully completed for induction in flight. The CE20 engine was operated with a 20.2t thrust level for the first 40 seconds, followed by an operation at 20t off-nominal zones before operating it at 22.2t for a duration of 435 seconds, by moving the thrust control valve,” ISRO said. The mixture ratio and thrust control were in open-loop mode, the space agency said. It added that during the test, the engine and the facility performed normally, and the required engine performance parameters were achieved as predicted. “The engine used for this hot test had undergone 11 hot tests with a cumulative duration of 2,720 seconds earlier. Thus, this engine has undergone 3,370 seconds cumulative burn duration at different thrust and mixture ratio levels,” ISRO said.
Scientists discover material that can be made like a plastic but conducts like metal
Scientists with the University of Chicago have discovered a way to create a material that can be made like a plastic but conducts electricity more like a metal. The research shows how to make a kind of material in which the molecular fragments are jumbled and disordered but can still conduct electricity extremely well. This goes against all of the rules we know about for conductivity. But the finding could also be extraordinarily useful; if you want to invent something revolutionary, the process often first starts with discovering a completely new material. Conductive materials are absolutely essential if you’re making any kind of electronic device, whether it be an iPhone, a solar panel, or a television. By far the oldest and largest group of conductors is the metals: copper, gold, aluminium. Then, about 50 years ago, scientists were able to create conductors made out of organic materials, using a chemical treatment known as “doping,” which sprinkles in different atoms or electrons through the material. This is advantageous because these materials are more flexible and easier to process than traditional metals, but the trouble is they aren’t very stable; they can lose their conductivity if exposed to moisture or if the temperature gets too high. But fundamentally, both of these organic and traditional metallic conductors share a common characteristic. They are made up of straight, closely packed rows of atoms or molecules. This means that electrons can easily flow through the material, much like cars on a highway. In fact, scientists thought a material had to have these straight, orderly rows in order to conduct electricity efficiently. Then researchers began experimenting with some materials discovered years ago, but largely ignored. He strung nickel atoms like pearls into a string of molecular beads made of carbon and sulfur and began testing. To the scientists’ astonishment, the material easily and strongly conducted electricity. What’s more, it was very stable. But to the scientists, the most striking thing was that the molecular structure of the material was disordered. The team tried to understand how the material can conduct electricity. After tests, simulations, and theoretical work, they think that the material forms layers, like sheets. Even if the sheets rotate sideways, no longer forming a neat stack, electrons can still move horizontally or vertically — as long as the pieces touch. The end result is unprecedented for a conductive material. The scientists are excited because the discovery suggests a fundamentally new design principle for electronics technology. Conductors are so important that virtually any new development opens up new lines for technology, they explained. One of the material’s attractive characteristics is new options for processing. For example, metals usually have to be melted in order to be made into the right shape for a chip or device, which limits what you can make with them, since other components of the device have to be able to withstand the heat needed to process these materials. The new material has no such restriction because it can be made at room temperatures. It can also be used where the need for a device or pieces of the device to withstand heat, acid or alkalinity, or humidity has previously limited engineers’ options to develop new technology. The team is also exploring the different forms and functions the material might make.
Researchers Create Smaller, Cheaper Flow Batteries for Clean Energy
Clean energy is the leading solution for climate change. But solar and wind power are inconsistent at producing enough energy for a reliable power grid. Alternatively, lithium-ion batteries can store energy but are a limited resource. Flow batteries offer a solution. Electrolytes flow through electrochemical cells from storage tanks in this rechargeable battery. The existing flow battery technologies are too expensive for practical application, but scientists in the School of Chemical and Biomolecular Engineering developed a more compact flow battery cell configuration that reduces the size of the cell by 75%, and correspondingly reduces the size and cost of the entire flow battery. Flow batteries get their name from the flow cell where electron exchange happens. Their conventional design, the planar cell, requires bulky flow distributors and gaskets, increasing size and cost but decreasing overall performance. The cell itself is also expensive. To reduce footprint and cost, the researchers focused on improving the flow cell’s volumetric power density (W/L-of-cell). They turned to a configuration commonly used in chemical separation — sub-millimeter, bundled microtubular (SBMT) membrane — made of a fiber-shaped filter membrane known as a hollow fiber. This innovation has a space-saving design that can mitigate pressure across the membranes that ions pass through without needing additional support infrastructure. They were interested in the effect of the battery separator geometry on the performance of flow batteries and were aware of the advantages that hollow fibers imparted on separation membranes and set out to realize those same advantages in the battery field. Applying this concept, the researchers developed an SMBT that reduces membrane-to-membrane distance by almost 100 times. The microtubular membrane in the design works as an electrolyte distributor at the same time without the need for large supporting materials. The bundled microtubes create a shorter distance between electrodes and membranes, increasing the volumetric power density. This bundling design is the key discovery for maximizing flow batteries’ potential. To validate their new battery configuration, the researchers used four different chemistries: vanadium, zinc-bromide, quinone-bromide, and zinc-iodide. Although all chemistries are functional, two were most promising. Vanadium was the most mature chemistry, but also less accessible, and the reduced form of it is unstable in air. They found zinc iodide was the most energy-dense option, making it the most effective for residential units. Zinc-iodide offered many advantages even compared to lithium: It has less of a supply chain issue and also can be turned into zinc oxide and dissolve in acid, making it much easier to recycle. This electrochemical solution for this unique shape of the flow battery proved more powerful than conventional planar cells. The researchers are already working on commercialization, focusing on developing batteries with different chemistries like vanadium and scaling up their size. Scaling will require coming up with an automated process to manufacture a hollow fiber module, which now is done manually, fiber by fiber. The SBMT cells could also be applied to different energy storage systems like electrolysis and fuel cells. The technology could even be strengthened with advanced materials and different chemistry in various applications.
Screen-Printing Method Can Make Wearable Electronics Less Expensive
The glittering, serpentine structures that power wearable electronics can be created with the same technology used to print rock concert t-shirts, new research shows. The study, led by Washington State University researchers, demonstrates that electrodes can be made using just screen printing, creating a stretchable, durable circuit pattern that can be transferred to fabric and worn directly on human skin. Such wearable electronics can be used for health monitoring in hospitals or at home. They wanted to make flexible, wearable electronics in a way that is much easier, more convenient and lower cost. That’s why they focused on screen printing: it’s easy to use. It has a simple setup, and it is suitable for mass production. Current commercial manufacturing of wearable electronics requires expensive processes involving clean rooms. While some use screen printing for parts of the process, this new method relies wholly on-screen printing, which has advantages for manufacturers and ultimately, consumers. In the study the team details the electrode screen-printing process and demonstrate how the resulting electrodes can be used for electrocardiogram monitoring, also known as ECG. They used a multi-step process to layer polymer and metal inks to create snake-like structures of the electrode. While the resulting thin pattern appears delicate, the electrodes are not fragile. The study showed they could be stretched by 30% and bend to 180 degrees. Multiple electrodes are printed onto a pre-treated glass slide, which allows them to be easily peeled off and transferred onto fabric or other material. After printing the electrodes, the researchers transferred them onto an adhesive fabric that was then worn directly on the skin by volunteers. The wireless electrodes accurately recorded heart and respiratory rates, sending the data to a mobile phone. While this study focused on ECG monitoring, the screen-printing process can be used to create electrodes for a range of uses, including those that serve similar functions to smart watches or fitness trackers, researchers said. The lab is currently working on expanding this technology to print different electrodes as well as entire electronic chips and even potentially whole circuit boards.