Aurelia Butler

Three-dimensional (3D) metal-plastic composite structures have widespread potential applicability in smart electronics, micro/nanosensing, internet-of-things (IoT) devices, and even quantum computing. Devices constructed using these structures have a higher degree of design freedom, and can have more complex features, complex geometry, and increasingly smaller sizes. But current methods to fabricate such parts are expensive and complicated.
Recently, a group of researchers from Japan and Singapore developed a new multimaterial digital light processing 3D printing (MM-DLP3DP) process to fabricate metal-plastic composite structures with arbitrarily complex shapes. Explaining the motivation behind the study, lead authors Professor Shinjiro Umezu, Mr. Kewei Song from Waseda University and Professor Hirotaka Sato from Nanyang Technological University, Singapore state, “Robots and IoT devices are evolving at a lightning pace. Thus, the technology to manufacture them must evolve as well. Although existing technology can manufacture 3D circuits, stacking flat circuits is still an active area of research. We wanted to address this issue to create highly functional devices to promote the progress and development of human society.” The study has been published in ACS Applied Materials & Interfaces.
The MM-DLP3DP process is a multi-step process that begins with the preparation of the active precursors — chemicals which can be converted into the desired chemical after 3D printing, as the desired chemical cannot be 3D printed itself. Here, palladium ions are added to light-cured resins to prepare the active precursors. This is done to promote electroless plating (ELP), a process that describes the auto-catalytic reduction of metal ions in an aqueous solution to form a metal coating. Next, the MM-DL3DP apparatus is used to fabricate microstructures containing nested regions of the resin or the active precursor. Finally, these materials are directly plated, and 3D metal patterns are added to them using ELP.
The research team manufactured a variety of parts with complex topologies to demonstrate the manufacturing capabilities of the proposed technique. These parts had complex structures with multimaterial nesting layers, including microporous and tiny hollow structures, the smallest of which was 40 μm in size. Moreover, the metal patterns on these parts were very specific and could be precisely controlled. The team also manufactured 3D circuit boards with complex metal topologies, like an LED stereo circuit with nickel and a double-sided 3D circuit with copper.
“Using the MM-DLP3DP process, arbitrarily complex metal-plastic 3D parts having specific metal patterns can be fabricated. Furthermore, selectively inducing metal deposition using active precursors can provide higher quality metal coatings. Together, these factors can contribute to the development of highly integrated and customizable 3D microelectronics,” Umezu, Song, and Sato state.
The new manufacturing process promises to be a breakthrough technology for the manufacturing of circuits, with applications in a diverse variety of technologies, including 3D electronics, metamaterials, flexible wearable devices, and metal hollow electrodes.
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Testing time perception in an unusually lifelike setting — a virtual reality ride on a New York City subway train — an interdisciplinary Cornell research team found that crowding makes time seem to pass more slowly.
As a result, rush-hour commutes on public transit may feel significantly longer than other rides that objectively take the same amount of time.
The research adds to evidence that social context and subjective feelings distort our sense of the passage of time, and may have practical implications for people’s willingness to use public transit, particularly after the pandemic.
“It’s a new way of thinking about social crowding, showing that it changes how we perceive time,” said Saeedeh Sadeghi, M.S. ’19, a doctoral student in the field of psychology. “Crowding creates stressful feelings, and that makes a trip feel longer.”
Sadeghi is the lead author of “Affective Experience in a Virtual Crowd Regulates Perceived Travel Time,” published Nov. 3 in the journal Virtual Reality. Co-authors are Ricardo Daziano, associate professor of civil and environmental engineering in the College of Engineering; So-Yeon Yoon, associate professor in the Department of Human Centered Design in the College of Human Ecology (CHE); and Adam K. Anderson, professor in the Department of Psychology and in CHE.
Prior research has identified subjective emotions, heart rate and a situation’s complexity, including the number of items requiring attention, among factors that can influence one’s experience of time. Experiments typically have been conducted in lab settings using simple tasks and stimuli, such as shapes or images on a computer screen, for short durations. More

Owing to their lightweight nature and flexibility, thermally conductive polymer composites are applied between a heat source and a sink in electronics to dissipate the generated heat to the surroundings. Efficient heat dissipation is achieved due to the use of fillers with certain orientations that facilitate heat flow. The conventional process of modifying the orientation of the filler material, however, is an energy-intensive process that requires the use of electric/magnetic fields and surface modifications that can compromise the filler’s quality and its thermal properties.
Now, in a new study, Professor Chae Bin Kim and his team at Pusan National University, Republic of Korea, have developed an energy-efficient process to change the orientation of the filler without the need for surface modifications.
This paper was made available online on 17 October 2022 and will be published in Volume 117 of the journal Polymer Testing on 1 January 2023.
The proposed method makes use of thermophoresis, a phenomenon in which a temperature gradient causes solid particles suspended in a fluid medium to move or rotate. To prepare the polymer composite, the researchers suspended thermally conductive hexagonal boron nitride (h-BN) filler particles in a UV-curable liquid and coated it between two glass plates. A temperature gradient was applied along the film thickness, causing the filler particles to rotate, and realign along the applied temperature gradient. On achieving the desired orientations, the composite was photocured, resulting in a solid composite with fixed filler orientations that form a heat transfer pathway.
“To our best knowledge, the current study is the first experimental demonstration of controlling anisotropic filler orientation using thermophoresis,” says Professor Kim.
Thermally conductive polymer composites such as thermal paste are used in phones, laptops, even in batteries. Considering the growing production of electronics and the expected transition to electric vehicles, the proposed method has the potential to lower the energy cost of manufacturing thermally conductive polymer composites. Furthermore, by avoiding the need for surface modifications, highly efficient thermally conductive polymer composites can be developed for improved heat dissipation and extend the life of electronics.
“Efficient heat dissipating materials can ensure best operating conditions for the device with improved reliability, lifespan, and user’s safety,” says Professor Kim.
Apart from improving thermal conductivity, fillers are also used to alter a composite’s optical, electrical, and mechanical properties. By offering a way to reorient the filler without any surface modifications, the proposed method can also be adopted to tune the properties of a wide range of polymer composites without deteriorating their quality.
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A team of quantum engineers at UNSW Sydney has developed a method to reset a quantum computer — that is, to prepare a quantum bit in the ‘0’ state — with very high confidence, as needed for reliable quantum computations. The method is surprisingly simple: it is related to the old concept of ‘Maxwell’s demon’, an omniscient being that can separate a gas into hot and cold by watching the speed of the individual molecules.
“Here we used a much more modern ‘demon’ — a fast digital voltmeter — to watch the temperature of an electron drawn at random from a warm pool of electrons. In doing so, we made it much colder than the pool it came from, and this corresponds to a high certainty of it being in the ‘0’ computational state,” says Professor Andrea Morello of UNSW, who led the team.
“Quantum computers are only useful if they can reach the final result with very low probability of errors. And one can have near-perfect quantum operations, but if the calculation started from the wrong code, the final result will be wrong too. Our digital ‘Maxwell’s demon’ gives us a 20x improvement in how accurately we can set the start of the computation.”
The research was published in Physical Review X, a journal published by the American Physical Society.
Watching an electron to make it colder
Prof. Morello’s team has pioneered the use of electron spins in silicon to encode and manipulate quantum information, and demonstrated record-high fidelity — that is, very low probability of errors — in performing quantum operations. The last remaining hurdle for efficient quantum computations with electrons was the fidelity of preparing the electron in a known state as the starting point of the calculation. More

New analysis of elite women’s basketball automatically pinpoints a team’s chances of high or low scoring plays despite the ball’s trajectory looking the same, in research developed by QUT data scientists.
The study, published recently in PLOS One, used existing data from 72 women’s international basketball games ranging from the 2014 FIBA World Championships to the 2016 Rio Olympics.
The results provide insights to support coaches to scrutinise teams’ effective or problematic plays by classifying and tracking the dynamics of ball movements as to whether a team scored and relating types of play to scoring outcomes.
While data on spatial characteristics like a basketball’s bounce, its speed, the possession time, points scored as well as previous teams’ history are already wide ranging, research attempting to cluster play types using ball movement is limited.
This new research, applying the concept of ‘dynamic time warping’, was led by Distinguished Professor Kerrie Mengersen and Dr Paul Wu from QUT’s Centre for Data Science, Dr Wade Hobbs from the Australian Institute of Sport, and University of Sydney and QUT student Alan Yu.
Dr Wu said the study was prompted by questions about the unpredictability of plays and whether that led to better scoring outcomes. More

Imagine a team of humans and robots working together to process online orders — real-life workers strategically positioned among their automated coworkers who are moving intelligently back and forth in a warehouse space, picking items for shipping to the customer. This could become a reality sooner than later, thanks to researchers at the University of Missouri, who are working to speed up the online delivery process by developing a software model designed to make “transport” robots smarter.
“The robotic technology already exists,” said Sharan Srinivas, an assistant professor with a joint appointment in the Department of Industrial and Manufacturing Systems Engineering and the Department of Marketing. “Our goal is to best utilize this technology through efficient planning. To do this, we’re asking questions like ‘given a list of items to pick, how do you optimize the route plan for the human pickers and robots?’ or ‘how many items should a robot pick in a given tour? or ‘in what order should the items be collected for a given robot tour?’ Likewise, we have a similar set of questions for the human worker. The most challenging part is optimizing the collaboration plan between the human pickers and robots.”
Currently, a lot of human effort and labor costs are involved with fulfilling online orders. To help optimize this process, robotic companies have already developed collaborative robots — also known as cobots or autonomous mobile robots (AMRs) — to work in a warehouse or distribution center. The AMRs are equipped with sensors and cameras to help them navigate around a controlled space like a warehouse. The proposed model will help create faster fulfillment of customer orders by optimizing the key decisions or questions pertaining to collaborative order picking, Srinivas said.
“The robot is intelligent, so if it’s instructed to go to a particular location, it can navigate the warehouse and not hit any workers or other obstacles along the way,” Srinivas said.
Srinivas, who specializes in data analytics and operations research, said AMRs are not designed to replace human workers, but instead can work collaboratively alongside them to help increase the efficiency of the order fulfillment process. For instance, AMRs can help fulfill multiple orders at a time from separate areas of the warehouse quicker than a person, but human workers are still needed to help pick items from shelves and place them onto the robots to be transported to a designated drop-off point inside the warehouse.
“The one drawback is these robots do not have good grasping abilities,” Srinivas said. “But humans are good at grasping items, so we are trying to leverage the strength of both resources — the human workers and the collaborative robots. So, what happens in this case is the humans are at different points in the warehouse, and instead of one worker going through the entire isle to pick up multiple items along the way, the robot will come to the human worker, and the human worker will take an item and put it on the robot. Therefore, the human worker will not have to strain himself or herself in order to move large carts of heavy items throughout the warehouse.”
Srinivas said a future application of their software could also be applied in other locations such as grocery stores, where robots could be used to fill orders while also navigating among members of the general public. He could see this potentially happening within the next three-to-five years.
“Collaborative order picking with multiple pickers and robots: Integrated approach for order batching, sequencing and picker-robot routing” was published in the International Journal of Production Economics. Shitao Yu, a doctoral candidate in the Department of Industrial and Manufacturing Systems Engineering at MU, is a co-author of the study.
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The emergence of distributed energy resources (DERs) — facilities owned by individuals or small companies that can generate, store and return power to energy grids — is transforming the way power is used across the world.
The technology is becoming more prevalent as society looks for alternative sources of energy, but its rapid growth brings with it a new field of vulnerabilities open to cyberattacks.
DERs like home-based solar panels or electric vehicle chargers rely on field devices known as smart inverters to interface with power grids. As a new study by Concordia researchers shows, these devices’ reliance on digital information and communication technology can be attacked in multiple ways by malicious actors, with serious repercussions for the public.
The paper, published in the IEEE: Transactions on Power Electronics journal, surveys the landscape of smart inverter cybersecurity and identifies attack strategies at the device and grid level. It also looks at ways to defend against, mitigate and prevent them.
“We are still in the first decade of trying to understand the problem and identifying the most prominent risks,” says the paper’s co-author Jun Yan, associate professor at the Concordia Institute for Information Systems Engineering.
“Threats are inevitable. We have so many homeowners and third parties using these devices that having a perfect line of defence is impossible. We must look at our strategic priorities to start.”
Yuanling Li, a Concordia PhD student and research intern at Ericsson’s Global Artificial Intelligence Accelerator (GAIA), is the paper’s lead author. More

Silicon carbide (SiC) is a semiconductor material that outperforms pure silicon-based semiconductors in several applications. Used mostly in power inverters, motor drives, and battery chargers, SiC devices offer benefits such as a high power density and reduced power losses at high frequencies even at high voltages. Although these properties and its relatively low cost make SiC a promising contender in various sectors of the semiconductor market, its poor long-term reliability has been an insurmountable barrier since the past two decades.
One of the most pressing issues with 4H-SiC -a SiC type with superior physical properties- is bipolar degradation. This phenomenon is caused by the expansion of stacking faults in 4H-SiC crystals. Put simply, small dislocations in the crystal structure grow over time into large defects called “single Shockley stacking faults” that progressively degrade performance and cause the device to fail. Although some methods to mitigate this problem exist, they make the device fabrication process more expensive.
Fortunately, a team of researchers from Japan led by Associate Professor Masashi Kato from the Nagoya Institute of Technology, have now found a feasible solution for this issue. In their study made available online on 5 November 2022 and published in the journal Scientific Reports on 5 November 2022, they present a fault suppression technique called “proton implantation” that can prevent bipolar degradation in 4H-SiC semiconductor wafers when applied prior to the device fabrication process. Explaining the motivation for this study, Dr. Kato says, “Even in the recently developed SiC epitaxial wafers, bipolar degradation persists in the substrate layers. We wanted to help the industry navigate this challenge and find a way for developing reliable SiC devices, and, therefore, decided to investigate this method for eliminating bipolar degradation.” Associate professor Shunta Harada from Nagoya University, and Hitoshi Sakane, an academic researcher from SHI-ATEX, both in Japan, were also part of this study.
Proton implantation involves “injecting” hydrogen ions into the substrate using a particle accelerator. The idea is to prevent the formation of single Shockley stacking faults by pinning down partial dislocations in the crystal, one of the effects of introducing proton impurities. However, proton implantation itself can damage the 4H-SiC substrate, due to which high-temperature annealing is used as an additional processing step to repair this damage.
The research team wanted to verify if proton implantation would be effective when applied before the device fabrication process, which typically includes a high-temperature annealing step. Accordingly, they applied proton implantation at different doses on 4H-SiC wafers and used them to fabricate PiN diodes. They then analyzed the current-voltage characteristics of these diodes and compared them to those of a regular diode without proton implantation. Finally, they captured electroluminescence images of the diodes to check whether stacking faults had formed or not.
Overall, the results were very promising as diodes that had undergone proton implantation performed just as well as regular ones but without signs of bipolar degradation. The deterioration of the current-voltage characteristics of the diodes caused by proton implantation at lower doses were not significant. However, the suppression of the expansion of single Shockley stacking faults was significant.
The researchers hope that these findings will help realize more reliable and cost-effective SiC devices that can reduce power consumption in trains and vehicles. “Although the additional fabrication costs of proton implantation should be considered, they would be similar to those incurred in aluminum-ion implantation, currently an essential step in the fabrication of 4H-SiC power devices.” speculates Dr. Kato. “Moreover, with further optimization of implantation conditions, there is a possibility of applying this method for the fabrication of other kinds of devices based on 4H-SiC.”
Hopefully, these findings will help unlock the full potential of SiC as a semiconductor material for powering next-generation electronics.
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