NREL research points to strategies for recycling of solar panels

DOE/NATIONAL RENEWABLE ENERGY LABORATORY

Researchers at the National Renewable Energy Laboratory (NREL) have conducted the first global assessment into the most promising approaches to end-of-life management for solar photovoltaic (PV) modules.

PV modules have a 30-year lifespan. There is currently no plan for how to manage this at end of their lifespan. The volume of modules no longer needed could total 80 million metric tons by 2050. In addition to quantity, the nature of the waste also poses challenges. PV modules are made of valuable, precious, critical, and toxic materials. There is currently no standard for how to recycle the valuable ones and mitigate the toxic ones.

Numerous articles review individual options for PV recycling but, until now, no one has done a global assessment of all PV recycling efforts to identify the most promising approaches.

"PV is a major part of the energy transition," said Garvin Heath, a senior scientist at NREL who specializes in sustainability science. "We must be good stewards of these materials and develop a circular economy for PV modules."

Heath is lead author of "Research and development priorities for silicon photovoltaic module recycling supporting a circular economy," which appears in the journal Nature Energy. His co-authors from NREL are Timothy Silverman, Michael Kempe, Michael Deceglie, and Teresa Barnes; and former NREL colleagues Tim Remo and Hao Cui. The team also collaborated with outside experts, particularly in solar manufacturing.

"It provides a succinct, in-depth synthesis of where we should and should not steer our focus as researchers, investors, and policymakers," Heath said.

The authors focused on the recycling of crystalline silicon, a material used in more than 90% of installed PV systems in a very pure form. It accounts for about half of the energy, carbon footprint, and cost to produce PV modules, but only a small portion of their mass. Silicon's value is determined by its purity.

"It takes a lot of investment to make silicon pure," said Silverman, PV hardware expert. "For a PV module, you take these silicon cells, seal them up in a weatherproof package where they're touching other materials, and wait 20 to 30 years--all the while, PV technology is improving. How can we get back that energy and material investment in the best way for the environment?"

The authors found some countries have PV recycling regulations in place, while others are just beginning to consider solutions. Currently, only one crystalline silicon PV-dedicated recycling facility exists in the world due to the limited amount of waste being produced today.

Based on their findings, the authors recommend research and development to reduce recycling costs and environmental impacts, while maximizing material recovery. They suggest focusing on high-value silicon versus intact silicon wafers. The latter has been touted as achievable, but silicon wafers often crack and would not likely meet today's exacting standards to enable direct reuse. To recover high-value silicon, the authors highlight the need for research and development of silicon purification processes.

The authors also emphasize that the environmental and economic impacts of recycling practices should be explored using techno-economic analyses and life-cycle assessments.

Finally, the authors note that finding ways to avoid waste to begin with is an important part of the equation, including how to make solar panels last longer, use materials more effectively, and produce electricity more efficiently.

"We need research and development because the accumulation of waste will sneak up on us," Silverman said. "Much like the exponential growth of PV installations, it will seem to move slowly and then rapidly accelerate. By the time there's enough waste to open a PV-dedicated facility, we need to have already studied the proper process."

If successful, these findings could contribute one piece of a PV circular economy.

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The U.S. Department of Energy's Solar Energy Technologies Office funded the analysis.

NREL is the U.S. Department of Energy's primary national laboratory for renewable energy and energy efficiency research and development. NREL is operated for the Energy Department by The Alliance for Sustainable Energy, LLC.

Designing better asteroid explorers

New research provides important information in improving the accuracy of data collection on asteroids

UNIVERSITY OF ROCHESTER

 

Recent NASA missions to asteroids have gathered important data about the early evolution of our Solar System, planet formation, and how life may have originated on Earth. These missions also provide crucial information to deflect asteroids that could hit Earth.

Missions like the OSIRIS-REx mission to Asteroid Bennu and the Hyabusa II mission to Ryugu, are often conducted by robotic explorers that send images back to Earth showing complex asteroid surfaces with cracked, perched boulders and rubble fields.

In order to better understand the behavior of asteroid material and design successful robotic explorers, researchers must first understand exactly how these explorers impact the surface of asteroids during their touchdown.

In a paper published in the journal Icarus, researchers in the University of Rochester's Department of Physics and Astronomy, including Alice Quillen, a professor of physics and astronomy, and Esteban Wright, a graduate student in Quillen's lab, conducted lab experiments to determine what happens when explorers and other objects touch down on complex, granular surfaces in low gravity environments. Their research provides important information in improving the accuracy of data collection on asteroids.

"Controlling the robotic explorer is paramount to mission success," Wright says. "We want to avoid a situation where the lander is stuck in its own landing site or potentially bounces off the surface and goes in an unintended direction. It may also be desirable for the explorer to skip across the surface to travel long distances."

The researchers used sand to represent an asteroid's surface in the lab. They used marbles to measure how objects impact the sandy surfaces at different angles, and filmed the marbles with high-speed video in order to track the marbles' trajectories and spin during impact with the sand.

"Granular materials like sand are usually quite absorbent upon impact," Quillen says. "Similar to a cannonball ricocheting off of water, pushed sand can act like a snow in front of a snowplow, lifting the projectile, causing it to skip off the surface."

The researchers constructed a mathematical model that includes the Froude number, a dimensionless ratio that depends on gravity, speed, and size. By scaling the model with the Froude number, the researchers were able to apply the knowledge gained from their experiments with the marbles to low gravity environments, such as those found on the surfaces of asteroids.

"We found that at velocities near the escape velocity--the velocity at which an object will escape gravitational attraction--many if not most rocks and boulders are likely to ricochet on asteroids," Wright says.

The results provide an explanation for why asteroids have strewn boulders and rocks that are perched on their surfaces, and they also influence the angle at which robotic missions will need to successfully touch down on the surface of an asteroid.

"Robotic missions that touch down on the surface of an asteroid will need to control the moment of touch down so that they don't bounce," Quillen says. "The robots can accomplish this by making their angle of impact nearly vertical, by reducing the velocity of impact to a very small value, or by making the velocity of impact large enough to form a deep crater that the robotic explorer won't bounce out of."

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More than one cognition: A call for change in the field of comparative psychology

Reviewing 40 years of research, a new paper challenges hypotheses and calls for a more biocentric understanding of cognitive evolution

MAX PLANCK INSTITUTE FOR THE SCIENCE OF HUMAN HISTORY

IMAGE: REVIEWING 40 YEARS OF RESEARCH, A NEW PAPER CHALLENGES HYPOTHESES AND CALLS FOR A MORE BIOCENTRIC UNDERSTANDING OF COGNITIVE EVOLUTION. view more 

CREDIT: CLOCKWISE FROM TOP LEFT: SIMONE PIKA, JULIANE BRAEUER, AND NATALIE UOMINI.

What makes a species "smart" and how do strategies for processing information evolve? What goes on in the minds of non-human animals and which cognitive skills can we claim as hallmarks of our species? These are some of the questions addressed by the field of comparative psychology, but a recent review in the Journal of Intelligence joins a growing body of literature that argues that studies of cognition are hampered by anthropocentrism and missing the bigger picture of cognitive evolution.

Based on 40 years of scientific literature and case studies of three non-human animals, the current paper identifies two main problems hindering research in comparative psychology.

First of which is the assumption that human cognition is the standard by which animal cognition should be measured. Human cognition is generally believed to be the most flexible, adaptable form of intelligence, with the abilities of other species evaluated in accordance to the extent they match human cognitive skills. Such an approach tends to overrate human-like cognitive skills and may overlook cognitive skills that play only a small part, or no part at all, in human psychology.

"This approach, whether implicit or explicit, can only produce a restrictive, anthropocentric view of cognitive evolution that ignores the incredible diversity of cognitive skills present in the world," says Juliane Bräuer, leader of the DogLab at the Max Planck Institute for the Science of Human History. Instead, research into the evolution of cognition should take a biocentric approach, considering each species investigated in its own right.

"Applying Darwinian thinking to comparative psychology and removing the 'benchmark' of human intelligence allows us to reveal the evolutionary, developmental and environmental conditions that foster the growth of certain unique abilities and the convergence of skills shared among a species," adds Natalie Uomini, the main co-author of the paper.

To further address this anthropocentric view, the authors also argue for increased focus on cognitive abilities in which animals outperform humans and discuss cases in which various species demonstrate better-than-human abilities in delayed gratification, navigation, communication, pattern recognition and statistical reasoning.

The second problem addressed is the assumption that cognition evolves as a package of skills similar to those apparent in humans, skills which taken together constitute "one cognition." The authors survey various major hypotheses from psychology, including Social Intelligence Hypothesis, Domestication Hypothesis and Cooperative Breeding Hypothesis, and argue that while each has evidence to support its claims, none account for the whole picture of cognition.

Instead of a cluster of linked skills originating from a single evolutionary pressure, the paper provides a framework for understanding cognitive arrays as the result of species-typical adaptations to the entire ecological and social environment.

"If we want to account for the fascinating variety of animal minds, comparative scientists should focus on skills that are ecologically relevant for a given species," say Bräuer and Uomini.

The paper discusses three distantly related species - chimpanzees, dogs and New Caledonian crows - that are highly sophisticated in one cognitive domain yet perform poorly in others generally believed to be linked.

The paper also lays out recommendations to make future experiments in comparative psychology ecologically relevant to the target species, including differentiating tasks for each species and accounting for diverse senses of perception, such as smell in the case of dogs.

In Germany, where the authors of the paper are based, comparative psychology is a relatively unknown field. The authors hope to stimulate interest and growth in the subject with future research dedicated to the study of each species' cognitive skills for their own sake, leading to a more relevant and holistic perspective on animals' cognitive skills and the recognition that there is not only "one cognition."

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GET RID OF HR

Tech sector job interviews assess anxiety, not software skills

NORTH CAROLINA STATE UNIVERSITY

 

A new study from North Carolina State University and Microsoft finds that the technical interviews currently used in hiring for many software engineering positions test whether a job candidate has performance anxiety rather than whether the candidate is competent at coding. The interviews may also be used to exclude groups or favor specific job candidates.

"Technical interviews are feared and hated in the industry, and it turns out that these interview techniques may also be hurting the industry's ability to find and hire skilled software engineers," says Chris Parnin, an assistant professor of computer science at NC State and co-author of a paper on the work. "Our study suggests that a lot of well-qualified job candidates are being eliminated because they're not used to working on a whiteboard in front of an audience."

Technical interviews in the software engineering sector generally take the form of giving a job candidate a problem to solve, then requiring the candidate to write out a solution in code on a whiteboard - explaining each step of the process to an interviewer.

Previous research found that many developers in the software engineering community felt the technical interview process was deeply flawed. So the researchers decided to run a study aimed at assessing the effect of the interview process on aspiring software engineers.

For this study, researchers conducted technical interviews of 48 computer science undergraduates and graduate students. Half of the study participants were given a conventional technical interview, with an interviewer looking on. The other half of the participants were asked to solve their problem on a whiteboard in a private room. The private interviews did not require study participants to explain their solutions aloud, and had no interviewers looking over their shoulders.

Researchers measured each study participant's interview performance by assessing the accuracy and efficiency of each solution. In other words, they wanted to know whether the code they wrote would work, and the amount of computing resources needed to run it.

"People who took the traditional interview performed half as well as people that were able to interview in private," Parnin says. "In short, the findings suggest that companies are missing out on really good programmers because those programmers aren't good at writing on a whiteboard and explaining their work out loud while coding."

The researchers also note that the current format of technical interviews may also be used to exclude certain job candidates.

"For example, interviewers may give easier problems to candidates they prefer," Parnin says. "But the format may also serve as a barrier to entire classes of candidates. For example, in our study, all of the women who took the public interview failed, while all of the women who took the private interview passed. Our study was limited, and a larger sample size would be needed to draw firm conclusions, but the idea that the very design of the interview process may effectively exclude an entire class of job candidates is troubling."

What's more, the specific nature of the technical interview process means that many job candidates try to spend weeks or months training specifically for the technical interview, rather than for the actual job they'd be doing.

"The technical interview process gives people with industry connections an advantage," says Mahnaz Behroozi, first author of study and a Ph.D. student at NC State. "But it gives a particularly large advantage to people who can afford to take the time to focus solely on preparing for an interview process that has very little to do with the nature of the work itself.

"And the problems this study highlights are in addition to a suite of other problems associated with the hiring process in the tech sector, which we presented at ICSE-SES [the International Conference on Software Engineering, Software Engineering In Society]," adds Behroozi. "If the tech sector can address all of these challenges in a meaningful way, it will make significant progress in becoming more fair and inclusive. More to the point, the sector will be drawing from a larger and more diverse talent pool, which would contribute to better work."

The study on technical interviews, "Does Stress Impact Technical Interview Performance?," will be presented at the ACM Joint European Software Engineering Conference and Symposium on the Foundations of Software Engineering, being held virtually from Nov. 8-13. The study was co-authored by Shivani Shirolkar, a Ph.D. student at NC State who worked on the project while an undergraduate; and by Titus Barik, a researcher at Microsoft and former Ph.D. student at NC State.

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Robot jaws shows medicated chewing gum could be the future

UNIVERSITY OF BRISTOL

 

IMAGE: A CLOSE UP OF THE HUMANOID CHEWING ROBOT. view more 

CREDIT: DR KAZEM ALEMZADEH, UNIVERSITY OF BRISTOL

Medicated chewing gum has been recognised as a new advanced drug delivery method but currently there is no gold standard for testing drug release from chewing gum in vitro. New research has shown a chewing robot with built-in humanoid jaws could provide opportunities for pharmaceutical companies to develop medicated chewing gum.

The aim of the University of Bristol study, published in IEEE Transactions on Biomedical Engineering, was to confirm whether a humanoid chewing robot could assess medicated chewing gum. The robot is capable of closely replicating the human chewing motion in a closed environment. It features artificial saliva and allows the release of xylitol the gum to be measured.

The study wanted to compare the amount of xylitol remaining in the gum between the chewing robot and human participants. The research team also wanted to assess the amount of xylitol released from chewing the gum.

The researchers found the chewing robot demonstrated a similar release rate of xylitol as human participants. The greatest release of xylitol occurred during the first five minutes of chewing and after 20 minutes of chewing only a low amount of xylitol remained in the gum bolus, irrespective of the chewing method used.

Saliva and artificial saliva solutions respectively were collected after five, ten, 15 and 20 minutes of continuous chewing and the amount of xylitol released from the chewing gum established.

Dr Kazem Alemzadeh, Senior Lecturer in the Department of Mechanical Engineering, who led the research, said: "Bioengineering has been used to create an artificial oral environment that closely mimics that found in humans.

"Our research has shown the chewing robot gives pharmaceutical companies the opportunity to investigate medicated chewing gum, with reduced patient exposure and lower costs using this new method."

Nicola West, Professor in Restorative Dentistry in the Bristol Dental School and co-author, added: "The most convenient drug administration route to patients is through oral delivery methods. This research, utilising a novel humanoid artificial oral environment, has the potential to revolutionise investigation into oral drug release and delivery."

VIDEO GAMES IMPACT GAMBLERS NOT SHOOTERS

Links between video games and gambling run deeper than previously thought, study reveals

A range of video game practices have potentially dangerous links to problem gambling, a study has revealed.

UNIVERSITY OF YORK

 

A range of video game practices have potentially dangerous links to problem gambling, a study has revealed.

Building on previous research by the same author, which exposed a link between problem gambling and video game loot boxes, the new study suggests that a number of other practices in video games, such as token wagering, real-money gaming, and social casino spending, are also significantly linked to problem gambling.

The research provides evidence that players who engage in these practices are also more likely to suffer from disordered gaming - a condition where persistent and repeated engagement with video games causes an individual significant impairment or distress.

Author of the study, Dr David Zendle from the Department of Computer Science at the University of York, said: "These findings suggest that the relationship between gaming and problem gambling is more complex than many people think."

"When we go beyond loot boxes, we can see that there are multiple novel practices in gaming that incorporate elements of gambling. All of them are linked to problem gambling, and all seem prevalent. This may pose an important public health risk. Further research is urgently needed"

For the study, a group of just under 1,100 participants were quota-sampled to represent the UK population in terms of age, gender, and ethnicity. They were then asked about their gaming and gambling habits.

The study revealed that a significant proportion (18.5%) of the participants had engaged in some behaviour that related to both gaming and gambling, such as playing a social casino game or spending money on a loot box.

Dr Zendle added: "There are currently loopholes that mean some gambling related elements of video games avoid regulation. For example social casinos are 'video games' that are basically a simulation of gambling: you can spend real money in them, and the only thing that stops them being regulated as proper gambling is that winnings cannot be converted into cash.

"We need to have regulations in place that address all of the similarities between gambling and video games. Loot boxes aren't the only element of video games that overlaps with gambling: They're just a tiny symptom of this broader convergence"

Last year, University of York academics, including Dr David Zendle, contributed to a House of Commons select committee inquiry whose report called for video game loot boxes to be regulated under gambling law and for their sale to children to be banned. Dr Zendle also provided key evidence to the recent House of Lords select committee inquiry that likewise produced a report recommending the regulation of loot boxes as gambling.

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'Beyond loot boxes: a variety of gambling-like practices in video games are linked to both problem gambling and disordered gaming' is published in the journal PeerJ.

Particulate plutonium released from the Fukushima Daiichi meltdowns

New research strongly suggests that the nano-scale heterogeneity that is common in normal nuclear fuels is still present in the fuel debris that remains inside the Fukushima's damaged reactors.

UNIVERSITY OF HELSINKI

IMAGE: (A)ELECTRON IMAGING OF A CSMP WITH ELEMENTAL MAPS. (B) SYNCHROTRON MICRO-FOCUS X-RAY FLUORESCENCE (ΜXRF) ELEMENTAL MAPS. (C) IMAGE OF URANIUM DIOXIDE INCLUSION IN THE CSMP. (D) URANIUM L3-EDGE X-RAY ABSORPTION... view more 

CREDIT: KYUSHU UNIVERSITY

Small amounts of plutonium (Pu) were released from the damaged Fukushima Daiichi Nuclear Power Plant (FDNPP) reactors into the environment during the site's 2011 nuclear disaster. However, the physical, chemical, and isotopic form of the released Pu has remained unknown.

Now, recent work published in the journal Science of the Total Environment has shown that Pu was included inside cesium-rich microparticles (CsMPs) that were emitted from the site. CsMPs are microscopic radioactive particles that formed inside the Fukushima reactors when the melting nuclear fuel interacted with the reactor's structural concrete. Due to loss of containment in the reactors, the particles were released into the atmosphere; many were then deposited across Japan.

Studies have shown that the CsMPs are incredibly radioactive and that they are primarily composed of glass (with silica from the concrete) and radio-cesium (a volatile fission product formed in the reactors). Whilst the environmental impact and distribution of the CsMPs is still an active subject of debate, learning about the chemical composition of the CsMPs has been shown to offer a much-needed insight into the nature and extent of the FDNPP meltdowns.

The study published in Science of the Total Environment, involving scientists from Japan, Finland, France, Switzerland, the UK, and USA, was led by Dr. Satoshi Utsunomiya and graduate student Eitaro Kurihara (Department of Chemistry, Kyushu University). The team used a combination of advanced analytical techniques (synchrotron-based micro-X-ray analysis, secondary ion mass spectrometry, and high-resolution transmission electron microscopy) to find and characterize the Pu that was present in the CsMP samples.

The researchers initially discovered incredibly small uranium-dioxide inclusions, of less than 10 nanometers in diameter, inside the CsMPs; this indicated possible inclusion of nuclear fuel inside the particles. Detailed analysis then revealed, for the first-time, that Pu-oxide concentrates were associated with the uranium, and that the isotopic composition of the U and Pu matched that calculated for the FDNPP irradiated fuel inventory.

Dr Utsunomiya stated "these results strongly suggest that the nano-scale heterogeneity that is common in normal nuclear fuels is still present in the fuel debris that remains inside the site's damaged reactors. This is important information as it tells us about the extent / severity of the melt-down. Further, this is important information for the eventual decommissioning of the damaged reactors and the long-term management of their wastes."

With regards environmental impact, Dr Utsunomiya states "that as we already know that the CsMPs were distributed over a wide region in Japan (up to 230 km from the FDNPP), small amounts of Pu were likely dispersed in the same way."

Professor Gareth Law, a co-author on the paper from the University of Helsinki, indicated that the team "will continue to characterize and experiment with the CsMPs, in an effort to better understand their long-term behavior and environmental impact. It is clear that CsMPs are an important vector of radioactive contamination from nuclear accidents."

Professor Bernd Grambow, a co-author from Nantes/France, states that "while the Pu released from the damaged reactors is low compared to that of Cs; the investigation provides crucial information for studying the associated health impact."

Professor Rod Ewing at Stanford University emphasized that "the study used an extraordinary array of analytical techniques in order to complete the description of the particles at the atomic-scale. This is the type of information required to describe the mobility of plutonium in the environment."

Utsunomiya concluded "It took a long time to publish results on particulate Pu from Fukushima. I would like to emphasize that this is a great achievement of international collaboration. It's been almost ten years since the nuclear disaster at Fukushima," he continued "but research on Fukushima's environmental impact and its decommissioning are a long way from being over."

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NOTE: Integration of the state-of-the-art analytical techniques was accomplished through a world-wide international network that included Kyushu University, University of Tsukuba, Tokyo Institute of Technology, National Institute of Polar Research, University of Helsinki, Paul Scherrer Institute, Diamond Light Source, SUBATECH (IMT Atlantique, CNRS, University of Nantes), and Stanford University.  

Additional information:

Satoshi Utsunomiya, Associate Professor
Department of Chemistry, Kyushu University, Japan
Tel: +81-92-802-4168 Fax: +81-92-802-4168
E-mail: utsunomiya.satoshi.998@m..kyushu-u.ac.jp

Gareth Law, Professor
Department of Chemistry, Radiochemistry Unit, University of Helsinki
Tel: +358-50-55-60920
E-mail: Gareth.law@helsinki.fi

Drones and artificial intelligence show promise for conservation of farmland bird nests

UNIVERSITY OF HELSINKI

 

Farmland bird species are declining over most of Europe. Birds breeding on the ground, are particularly vulnerable because they are exposed to mechanical operations, like ploughing and sowing, which take place in spring and often accidentally destroy nests.

Locating nests on the ground is challenging for the human eye, and highly time-consuming

Researchers flew a drone carrying a thermal camera over agricultural fields to record images. These were then fed to an artificial intelligence algorithm capable of accurately identifying nests, a first step to aid their protection. Researchers tested the system in Southern Finland near University of Helsinki's Lammi Biological Station, using wild nests with eggs of the Lapwing Vanellus vanellus.

"We have been involved in conservation of ground-nesting farmland birds for years, and realized how difficult it is to locate nests on the ground. At least at high latitudes, the temperature of these nests is typically higher than that of the surrounding environment. Hence, we thought that thermal cameras could assist. A small pilot study indicated that thermal vision is hampered by vegetation and objects on the ground. Therefore to make this an efficient system, we thought that the camera could be flown using a drone, and artificial intelligence could help to analyse the resulting thermal images. We show that this works. However, the system performed best under cloudy and cold conditions, and on even grounds," says Andrea Santangeli, an Academy of Finland fellow at the Finnish Museum of Natural History Luomus, University of Helsinki.

Drone technology becoming rapidly popular in conservation

It is possible to map in near real-time the spread of diseases on crops in agricultural areas using drones with various sensors. The latter is an integral part of precision agriculture, a new way of crop production that makes large use of drone technology to monitor crops and maximize production efficiency.

Studies like this one can help pave the way to integrate bird nest detection within the drone borne sensors used in precision agriculture, and automate a system for saving those nests.

"The conservation community must be ready to embrace technology and work across disciplines and sectors in order to seek efficient solutions. This is already happening, with drone technology becoming rapidly popular in conservation. A next and most challenging step will be to test our system in different environments and with different species. Our auspice is that this system will be, one day, fully integrated into agricultural practices, so that detecting and saving nests from mechanical destruction will become a fully automated part of food production," says Andrea Santangeli.

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Butterfly wings inspiring next-gen technological innovations

SCIENCE CHINA PRESS

 

IMAGE: SCHEME OF BUTTERFLY WING ARCHITECTURES AND ASSOCIATED APPLICATIONS. view more 

CREDIT: ©SCIENCE CHINA PRESS

The catastrophic effects of global environmental degradation, health deterioration and diminishing energy resources are demanding remedy measures aimed at environmental conservation, health interventions and harnessing of the abundant and renewable energy resources. Consequently, sensors and renewable energy harnessing systems have emerged as worthwhile solutions to the existent challenges. However, conventional sensors and renewable energy harnessing systems have presented diminished efficiency and performance to be improved. Therefore, current research trends are focusing on improving the efficiency and performance of these systems.

For centuries, nature has availed an unlimited cache of evolved biological species with improved energy harnessing capabilities and heightened responses to external stimuli, including temperature, pH, humidity and chemical molecules. Specifically, butterfly wings have gained research and aesthetic popularity for their vivid coloring, architypes of unique micro/nanostructures, sensitivity and effective responses to stimuli. While insect enthusiasts marvel at the beautiful wing coloration and patterning, researchers have determined that the vivid coloration and wing properties result from the structures and pigments found in the wing scales. The huge variety of beautifully colored wings has led researchers to classify the various unique wing scale architectures. Equally, researchers have made attempts to mimic the wing properties in fabrication of various manmade functional materials and systems, such as sensors and energy harnessing applications.

In the overview published in National Science Review, researchers in the State Key Laboratory of Metal Matrix Composites at Shanghai Jiao Tong University, Shanghai, China present the recent research progress in sensor and energy applications inspired by butterfly wings. In their review, Zhang W. and co-workers highlight the genesis of wing scale development and the subsequent formation of wing scale architectures. They describe the general appearance of the wing scale architectures as having three distinct regions namely, the highly convoluted upper lamina, flat and featureless lower lamina and pillar-like connection of the two layers called trabeculae. In addition, the authors discuss the most recent wing structure classification based on variations in specialized regions of the architectures. These wing scale architecture variations influence wing coloration among other properties, including porosity, surface area and responses to stimuli.

Recently, researchers have worked on a variety of sensor and energy systems with the aim of mimicking the properties of natural species into manmade functional systems. This published review has focused on the progress achieved in recent research towards the fabrication of sensor and energy systems inspired by butterfly wings. By employing the different properties of butterfly wings, featured researches have successfully fabricated thermal, medical and vapor sensors, anti-counterfeit security devices, photocatalysts, photovoltaic systems, triboelectric nanogenerators and energy storage systems. Comparatively, these featured systems have demonstrated competitive efficiency and performance to similar systems inspired by other natural species.

Unfortunately, more research is still necessary to achieve optimal replication of natural properties onto manmade functional systems. As a result, authors suggest that the application scope should extend to photothermal imaging and therapy in cancer treatment and management. The good performance recorded by medical sensors for health monitoring and photothermal capabilities of butterfly wing inspired materials will generate sufficient mechanism for the detection, imaging, therapy and monitoring of terminal diseases. Similarly, photothermal materials inspired by butterfly wings can gain interest in the emerging stealth technologies research for modern-day warfare and scientific research technologies, such as rockets. Lastly, butterfly wings have exhibited numerous and diverse properties that enable them effectively respond to external stimuli. Research should envision tapping onto these characteristics in fabrication of functional systems with multiple responses and high efficiencies. This should be a real break-through in attaining next generation applications that optimize the properties of natural species and meet the global energy shortages, environmental degradation and deteriorating health conditions.

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This research received funding from the Key Program for International S&T Cooperation Program of China, National Natural Science Foundation of China, Shanghai Science and Technology Committee and National Key Research and Development Program.

See the article:

Maurice I. Osotsi, Wang Zhang, Imran Zada, Jiajun Gu, Qinglei Liu, Di Zhang

Butterfly wing architectures inspire sensor and energy applications

Natl Sci Rev 2020; doi: 10.1093/nsr/nwaa107

https://doi.org/10.1093/nsr/nwaa107

The National Science Review is the first comprehensive scholarly journal released in English in China that is aimed at linking the country's rapidly advancing community of scientists with the global frontiers of science and technology. The journal also aims to shine a worldwide spotlight on scientific research advances across China.

Towards prosperous public goods with freedom of choice

TOKYO INSTITUTE OF TECHNOLOGY

 

IMAGE: WITHOUT A POSSIBILITY TO PRIORITIZE THEIR CONTRIBUTIONS (LEFT), SAY, BETWEEN A LOCAL PARK, A LIBRARY, OR AN ENVIRONMENTAL INITIATIVE, PEOPLE ARE LESS LIKELY TO PARTICIPATE IN PUBLIC-GOODS PROVISION. LOW PARTICIPATION... view more 

CREDIT: TOKYO TECH

From climate and biodiversity to public health and law enforcement, public goods benefit all. They are produced or maintained through widespread participation in public-goods provision that is vulnerable to low participation rates. Avoiding this vulnerability has spurred a continuing search for better ways to promote participation.

Now, a study by an international group of researches shows that the ability to freely choose preferred public goods adds to their value by increasing participation rates. The findings offer surprising insights into human decision making, while also suggesting that societies may profit from bottom-up approaches to public-goods provision.

Decades of experiments on human behavior and public goods games have consistently confirmed that initial participation rates hover around 50%, but then decrease due to free riding (the act of piggybacking on the goodwill of others). Recent theoretical research suggests that social networks are instrumental in offsetting free riding but so far, large-scale experiments have failed to support these theoretical predictions.

To investigate factors affecting public-goods provision, a research team coordinated by Marko Jusup from Tokyo Institute of Technology (Tokyo Tech) in Japan and Zhen Wang from Northwestern Polytechnical University in China conducted a social-dilemma experiment designed specifically to reveal what drives participation rates. Is it global characteristics of social networks or local circumstances of each individual?

The team organized a game experiment played by 596 students who were equally distributed across three social-network configurations and two experimental conditions. Under control conditions, players could only decide whether to participate in public goods provision or not. A decision to participate implied contributing one unit of wealth to each public good within their reach. The total contribution would then be multiplied by an interest rate and divided equally not only between actual contributors, but also free riders who could have contributed, but chose not to. Free riders could thus piggyback on the effort of contributors to gain benefits without sharing costs. Players under treatment conditions could additionally decide how much to contribute to each of the public goods within their reach.

A player with access to five different public goods would, by opting to participate under control conditions, contribute one unit of wealth to each of the public goods for a total contribution of five units. The same player under treatment conditions would also contribute a total of five units of wealth, but with a caveat that how much goes to each of the five public goods is subject to free will.

The study found that local circumstances are more important than the global characteristics of social networks. Changing the network configuration does not appear to affect player decisions in any significant way, whereas letting players distribute their wealth freely increases participation in public goods provision, motivates better provisioning, and thus adds value to public goods.

Remarkably, treatment conditions jump-started participation from the very beginning to form a cooperative milieu that is independent of social-network characteristics. Jusup comments: "This is surprising! We expected initial participation to be similar under both control and treatment conditions. Only later in the game did we expect gradual learning and optimization from players who could choose freely. We observed that increased participation in public-goods provision happens from the very first round of the game, as if the players could feel that extra freedoms weaken the underlying dilemma of whether to participate or not. Over time, more participation leads to more wealth, generating something akin to a free lunch for players under treatment conditions."

The study identified three behavioral types that account for the results: prosocial, antisocial, and conditional cooperators. Prosocial players participate almost unconditionally, antisocial players mostly forgo participation, and conditional cooperators refuse participation when there are no other participators around. Notably, freedom of choice seems to foster conditional cooperation, as evidenced by the fact that conditional cooperators are mostly absent under control conditions but predominate under treatment conditions. This occurs because in the latter case, players receive much clearer signals from their surroundings, and can then better gauge the overall cooperativeness of their neighbors.

There are many interesting implications for socio-economic settings. "Policymakers, for instance, could facilitate raising residential taxes by offering a portfolio of public goods for taxpayers to choose from," write the researchers in their study published in Proceedings of the National Academy of Sciences.

"And by doing so, voters could decouple long-term, life-improving, public-goods projects from the whims and fancies of political election cycles," adds Ivan Romi?, a co-author of the study. "Going beyond the politics, private companies might be able to motivate customers to pay premium product prices if the premium could be directed toward a public good of customers' choosing, thus stepping up the corporate social responsibility while remaining profitable."

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