Bio-inspired battery design

Flexible sodium-ion batteries improved by electrolyte methylation

Peer-Reviewed Publication

WILEY

Flexible aqueous batteries, such as those used in portable electronics, often contain a hydrogel electrolyte containing water and salt. Using a chemical modification inspired by nature, a team of Chinese researchers have now significantly increased the salt stability of hydrogels used in sodium-ion batteries. A simple methylation of the hydrogel’s structural polymer prevented salting-out and improved battery capacity and cycling performance, the team report in the journal Angewandte Chemie.

Sodium-ion batteries are a promising alternative to lithium-ion batteries, since they contain cheaper and more eco-friendly materials than Li-ion batteries. However, new batteries require the development of many new components, all of which have to be adapted to the sodium ion. One of the most essential components is the electrolyte, which in the case of thin, flexible batteries, is often in the form of a hydrogel. These flexible, water-containing materials absorb dissolved sodium salts and can conduct ions.

Despite the suitability of hydrogels, an as-yet unsolved problem is phase separation and salting out at the high salt concentrations needed for a broad electrochemical stability window. Guanglei Cui and colleagues from the Chinese Academy of Sciences in Qingdao, China have now succeeded in modifying a hydrogel for a sodium-ion battery to make it absorb considerably more salt in a stable and secure manner.

To achieve this, they turned to a technique also employed in nature for the regulation of water- and salt-binding in large biomolecules: methylation. In proteins, methylation causes the “capping” of amine and amide groups, which become less accessible for water molecules that play a role in cross-linking within the protein structure and the dissolution of salt ions.

As the polyamide polymers used for hydrogels also contain amide groups, their extensive cross-linking through water molecules can cause salting out, which leads to the breakdown of the electrolyte. With this in mind, the team compared a hydrogel made of a common polyamide to a hydrogel made of a polyamide with methylated amide groups. The latter was able to absorb significantly more salt than the original variant. Even at record-high salt concentrations, the hydrogel electrolyte remained transparent and stable.

The higher salt content means that the electrochemically usable voltage range of the cell can be expanded. In addition, the team did not observe any signs of disintegration at the electrodes, better cycling stability and the assembled battery cell achieved a greater capacity than the non-methylated variant. It was even possible to use inexpensive aluminum foil as a current collector in this system.

The authors suggest that simple polyamide methylation could also be suitable for other technologies, for example, in drug development, to make hydrogels more resistant to salts and therefore more stable.

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About the Author

Guanglei Cui is a professor at the Qingdao Institute of Bioenergy and Bioprocess Technology at the Chinese Academy of Sciences, Qingdao, China. His research interests mainly focus on low-cost energy storage systems, solid-state batteries, deep-sea power supply systems, and photoelectric conversion devices.

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JOURNAL

Angewandte Chemie International Edition

DOI

10.1002/anie.202311589 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

A Bio-Inspired Methylation Approach to Salt-Concentrated Hydrogel Electrolytes for Long-Life Rechargeable Batteries

 

Andalusian families do not have the same bilingual education opportunities

According to a study, factors such as their place of residence, the economic level of their neighborhoods, and school type, strongly limit equal access to bilingual education in Andalusia

Peer-Reviewed Publication

UNIVERSITY OF CÓRDOBA

 

IMAGE: 

THE RESEARCHER ALBERTO ÁLVAREZ DE SOTOMAYOR

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CREDIT: UNIVERSITY OF CORDOBA

According to a study, factors such as their place of residence, the economic level of their neighborhoods, and school type, strongly limit equal access to bilingual education in Andalusia

Bilingual education programs, which began to be implemented in Spain in the mid-2000s, and were created, in part, to prevent inequalities from determining access to foreign language education (usually English) are characterized by precisely what they wanted to avoid: disparities in access. According to a study featuring participation by University of Cordoba Sociology Area researcher Alberto Álvarez de Sotomayor, Pablo de Olavide University researcher Juan Miguel Gómez Espino, and Ricardo Barbieri, a former student for a Degree in Primary Education at the UCO, access to bilingual primary education in Andalusia is shaped by a series of geographical, social and economic factors, which prevent families from choosing a bilingual center with equal opportunities.

Thus, factors such as the family's area of residence, economic level, and the possibility of attending public, semi-private, or private schools are those that end up limiting students' opportunities to access a bilingual school. If a family residing in the Polígono Sur area of Seville, for example, would like to choose this type of education for their children, this will be difficult, since none of the eight primary schools in their area are bilingual.

According to the study, published in the journal Language and Education, inequality is also the result of two political-administrative decisions. First, the voluntary nature of bilingual teaching programs; it is the schools that decide whether or not to adhere to this program, which, in itself, gives rise to possible inequalities between students the important area of learning English. Then there is the school admissions model, according to which, in the event of many requests for slots at a school, the Public Administration prioritizes "areas of influence," a territorial delimitation that (among other secondary factors)  assigns families higher scores if they reside near the school.

Taking into account these two characteristics of the Andalusian educational system (and practically all of Spain), the research team studied, through cartographic and statistical analyses, the distribution of primary education centers in the 29 municipalities of Andalusia with more than 50,000 inhabitants. Although future studies will expand both the size of the municipality (to also include rural areas) and the teaching stage, focusing on Primary Education is key because, as Álvarez de Sotomayor explains, early ages are the most important when it comes to the acquisition of second languages and, therefore, the inequalities that could be generated are potentially greater during it.

Of those 29 municipalities, the researchers analyzed a series of factors that could influence inequality: whether or not the schools were bilingual, the type of school (public, semi-private or private), its area of influence, the economic level of the population that lives within that area, and the distance between the schools, among others. Based on these factors, the study found that the variable that most impacts access to bilingual education is type of school. Public schools offer bilingual education to a much lesser extent than semi-private or private ones. In fact, in the 29 municipalities studied, only 34% of public schools offered bilingual education, while in the semi-private schools the percentage rose to 72%. At private schools the figure was 62%, but not taking into account international schools, which do not fall within the Andalusian educational system and are not governed by Spanish legislation. In the words of Álvarez de Sotomayor "the inequality between school types is great, and is also associated with the socioeconomic issue, because not all people can afford to attend private or semi-private schools."

There are areas of influence where many bilingual schools are concentrated, while there are others that have none, or few. Therefore, depending on where they live, families have more or fewer opportunities to access this type of education. This is related to the population's economic level; areas of influence with moderate or high economic levels are those with the most bilingual schools, while areas of influence that coincide with the poorest neighborhoods have hardly any bilingual centers, or none at all.

Knowing about opportunities for bilingual education becomes more relevant because families don't choose in a vacuum, but between a series of opportunities. "It's important to know families' real opportunities to access this type of education. Based on this we will know the extent to which a program created to mitigate the inequality that existed in terms of foreign language levels between social classes, or between rural and urban areas, is helping to mitigate these inequalities or not. What we are seeing is that it is doing the opposite, to reproducing those inequalities," says Álvarez de Sotomayor.

To alleviate this situation the research team proposes three possible solutions: reconfigure the areas of influence, change the admissions model, or encourage schools located in low-income neighborhoods to opt for bilingual education.

EQUIBIL Project

The study is part of a broader one funded by the Ministry of Science and Innovation as part of the 2021 Knowledge Generation Projects, under the title "Equity and bilingual education (Spanish-English) in school quasi-market contexts. A study of the Andalusian case " (EQUIBIL). This project aims to expand knowledge of the implications of Spanish-English bilingual school programs in terms of educational equity. To this end, it has two general objectives: first, to study equal opportunities in access to them by analyzing the dynamics of school markets and the logic of the main agents that make them up, paying special attention to possible effects on school segregation processes;  second, to evaluate the effects of these bilingual programs on equal educational opportunities in terms of academic and linguistic achievement in English.

Reference:

Alberto Álvarez-Sotomayor, Juan Miguel Gómez-Espino and Ricardo Barbieri, “Mapping the opportunities of attending bilingual schools in Spain”, Language and Education, https://doi.org/10.1080/09500782.2023.2240294.

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JOURNAL

Language and Education

DOI

10.1080/09500782.2023.2240294 

ARTICLE TITLE

“Mapping the opportunities of attending bilingual schools in Spain”

 

Researchers propose radical change in how animal facial expressions are defined and studied

A new approach to analyzing facial expressions has been created to help better understand animal behavior

Peer-Reviewed Publication

UNIVERSITY OF PORTSMOUTH

Researchers have developed a new method to analyse facial expressions, as part of efforts to better understand animal communication.

The human Facial Action Coding System, or FACS, was originally created in the seventies to break down facial expressions into individual components of muscle movement, called Action Units (AU).

Behaviour experts have combined this system with the Social Network Analysis, which is used to measure relationships between muscle movements, to develop a statistical package known as NetFACS. 

The process allows researchers to answer questions about the use of specific facial movements, the combination of movements, and the facial communication system as a whole in humans and non-human animals.

Dr Jerome Micheletta from the Centre for Comparative and Evolutionary Psychology at the University of Portsmouth, said: “Communication is a defining feature of sociality, and faces offer others a wealth of information about identity, intentions and sometimes emotions.

“Despite this, we know little about what makes facial communication complex, and how to distinguish between species that have sophisticated facial communication, and those that don’t.

“While the FACS system helps label facial movements precisely and objectively, this new framework can be used by researchers to analyse them, and ultimately improve our understanding of the evolution of communication across species.”

Furthering our knowledge of animal behaviour is important, as it puts us in a stronger position to understand conservation problems, and evaluate the importance of human-related threats.

Professor Bridget Waller from Nottingham Trent University added: “We see facial expressions as facial movements that are linked with each other, interacting to produce a way to communicate. Our method considers the dynamic nature of facial expressions and therefore, better reflects its complexity.”

The NetFACS project has been funded by the Leverhulme Trust, and is a collaboration between the universities of Portsmouth, Nottingham Trent, Lincoln, St Andrews and the French National Centre for Scientific Research.

The team has trialled the NetFACS system by examining three species of macaques (rhesus, Barbary and crested). 

“The interesting thing with these species is that they vary in social tolerance, and therefore social complexity”, explained Dr Micheletta.

“It’s widely believed that animals living in large groups with greater complex relationships and social roles, will demonstrate greater and more complex communication.”

To test this theory, experts have coded facial behaviour of macaques in more than 3,000 social interactions across the contexts of aggressive, submissive, and affiliative.

Using the Facial Action Coding System for macaques (MaqFACS), the team found the more tolerant species of macaques had more complex facial communication. 

Their paper, published in eLife, says crested macaques use a higher diversity of facial behaviour more often, compared to Barbary and rhesus macaques.

Lead author, Dr Alan Rincon, said: “We were able to predict whether an animal was being aggressive, submissive or affiliative from their facial behaviour MaqFACS better than chance in all three species. 

“However, prediction accuracy was lowest for the more tolerant and socially complex species, the crested macaques, indicating that they have a more complex facial communication system. 

“Overall these results support the predicted link between social and communicative complexity and therefore help us better understand the evolution of communication.”

Dr Micheletta added: “Our next steps are exploring the facial repertoire of macaques in more detail, looking at how social factors such as social status and social integration are linked to facial communication.

“We also plan to look at the relationship between the nature and quality of social relationships (dominance relationships, kinship, social bonds) and facial communication. We would also continue to develop NetFACS, in particular implementing functions that would allow us to study the temporal dynamics  of facial communication in more detail.”

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JOURNAL

eLife

DOI

10.7554/eLife.87008.3 

METHOD OF RESEARCH

Observational study

SUBJECT OF RESEARCH

Animals

ARTICLE TITLE

Higher social tolerance is associated with more complex facial behavior in macaques

ARTICLE PUBLICATION DATE

3-Oct-2023

Awe-inspiring science can have a positive effect on mental wellbeing, new research finds

 MAGICK; THE METHOD OF SCIENCE AND THE AIM OF RELIGION

UNIVERSITY OF WARWICK

Research led by psychologists at the University of Warwick has revealed a profound connection between the spirituality of science and positive wellbeing, much like the benefits traditionally associated with religion.

The research explored how people use science as a source of spirituality and its connection with their sense of wellbeing.

Dr Jesse Preston, Associate Professor in the Department of Psychology at the University of Warwick and lead author of the study said: “Spirituality is most often associated with religion, but science can be a powerful source of awe and wonder for many. It can provide a meaningful source of understanding oneself and the universe, and it can foster a sense of connection to others and our place in the world.”

Science parallels positive wellbeing observed in religious people

In three studies, Dr. Preston and her research team surveyed 1197 people (602 men, 589 women, and 6 others) on their attitudes towards religious beliefs, spirituality and their interest and belief in science.

The first study established the concept of “Spirituality of Science”, and asked people about feelings of transcendence, connection and meaning when engaging with science. Participants’ responses were compared with other attitudes towards science, including an interest in science and belief in science, feelings of awe, meaning in their lives and religious beliefs.

Spirituality of Science was related to belief in science, but unlike other attitudes including interest in science and belief in science, Spirituality of Science was also associated with feelings of awe and general spirituality. This showed that scientific sources of spirituality may be psychologically similar to religious spirituality.

In the second study, the researchers focused specifically on a group of 526 atheists and agnostics, and found that Spirituality of Science was correlated with measures of psychological wellbeing, such as happiness, and meaning in life.

Preston explained: “Previous research has found that religious belief generally predicts positive mental wellbeing, but it has also implied that non-religious people may be subject to poorer psychological wellbeing. This research has found that in fact, sources of spirituality outside of religion, like science, can have similar positive effects.”

Meaningful experiences could improve educational outcomes in science

The third study investigated links between Spirituality of Science and engagement and learning in science, and found that spiritual experiences in science predicted stronger engagement and recall of scientific information.

Dr Preston says the findings of the research could improve the teaching and learning of science in schools and predict better educational outcomes:

“Although science and religion differ in many ways, they share a capacity for spirituality through feelings of awe, coherence, and meaning in life. This capacity for spirituality has some important benefits and implications, as this research has found.

“People with greater feelings of Spirituality of Science were more positively engaged with science material, which predicted better science performance. And in a group of atheists and agnostics, Spirituality of Science predicted measures of well-being and meaning in life, paralleling the positive effects of religion that is frequently observed in religious people.

Dr Preston added: “This work contributes not only to our current understanding of science attitudes but also to our general understanding of spirituality.”

The paper, Spirituality of Science: Implications for Meaning, Well-Being, and Learning has been published in Personality and Social Psychology Bulletin.

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JOURNAL

Personality and Social Psychology Bulletin

DOI

10.1177/01461672231191356 

SUBJECT OF RESEARCH

People

ARTICLE TITLE

Spirituality of Science: Implications for Meaning, Well-Being, and Learning

 

Bumblebees drop to shake off Asian hornets

Peer-Reviewed Publication

UNIVERSITY OF EXETER

 

IMAGE: 

ASIAN HORNETS

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CREDIT: SANDRA ROJAS-NOSSA

Bumblebees have a remarkably successful method for fighting off Asian hornets, new research shows.

When attacked, buff-tailed bumblebees drop to the ground – taking the hornets down with them. This either causes the hornet to lose its grip, or the bee raises its sting and tussles until the hornet gives up.

University of Exeter scientists witnessed over 120 such attacks, and were stunned to find that bumblebees fought off the hornets every time.

Despite this, they found bumblebee colonies had reduced growth rates in areas with high numbers of Asian hornets – suggesting the hornets still had a negative impact, even if their attacks at colony entrances usually failed.

Asian hornets (also known as yellow-legged hornets) have already invaded much of mainland Europe and parts of east Asia, and have recently been reported in the US for the first time.

Sightings in the UK and continental Europe are at record levels this year – raising fears for pollinators and prompting substantial control efforts.

“Asian hornets prey on a wide range of insects, including honey bees, but little is known about their impact on other pollinators,” said Thomas O'Shea-Wheller, of the Environment and Sustainability Institute on Exeter’s Penryn Campus in Cornwall.

“With honey bees, the hornets do something called ‘hawking’ – hovering outside the bees’ nest and attacking returning foragers as they fly past.

“We recorded hornets doing the same thing to bumblebees, but with the surprising difference that in our observations, they were entirely unsuccessful.”

In the study, commercially reared bumblebee colonies were placed at 12 locations across the province of Pontevedra, Spain, with varying local Asian hornet densities.

Colonies were weighed every two days (weight change is a measure of colony growth) and those in areas with higher Asian hornet densities grew more slowly.

“We can’t say for certain why this is,” O'Shea-Wheller said.

“It’s possible that some external factor is good for Asian hornets, allowing them to thrive, but bad for bumblebees.

“However, it’s perhaps more likely that the presence of Asian hornets limits the success of bumblebee colonies.

“Although the attacks we witnessed at colony entrances were unsuccessful, bumblebees have been reported in the diet of Asian hornets, and the hornets are known to prey on them elsewhere.

“Furthermore, defending against such attacks is likely energetically costly – and when hornet abundance is high, this could be a major problem for bees out foraging.

“Hornets also consume nectar from flowers, meaning they compete directly with bees for food and harass them at flower patches via constant attacks.”

Commenting on the hornets’ low success rate during attacks, O'Shea-Wheller said: “I have seen hornets attack bumblebees of all sizes, including some that are larger than them.

“They are very persistent and generalist predators, so these attacks may still be worthwhile despite the high failure rate, as long as they sometimes get a kill.”

Buff-tailed bumblebees (Bombus terrestris) have not evolved alongside Asian hornets (Vespa velutina), so O'Shea-Wheller said their successful defensive strategy may well be an “evolutionary coincidence”.

“While honey bees are often unable to escape the clutches of Asian hornets once grappled in the air, the bumblebees’ defensive response of dropping to the ground appears to be more successful,” he said.

In addition to the University of Exeter, the research team included scientists from the University of Vigo and the University of Santiago de Compostela.

The study was funded by the Biotechnology and Biological Sciences Research Council (BBSRC) and the European Regional Development Fund (ERDF).

The paper, published in the journal Communications Biology, is entitled: “Quantifying the impact of an invasive hornet on Bombus terrestris colonies.”

 

Hornet and bumblebee

CREDIT

Thomas O'Shea-Wheller

Hornet in hand

CREDIT

Peter Kennedy

JOURNAL

Communications Biology

DOI

10.1038/s42003-023-05329-5 

METHOD OF RESEARCH

Observational study

SUBJECT OF RESEARCH

Animals

ARTICLE TITLE

Quantifying the impact of an invasive hornet on Bombus terrestris colonies

ARTICLE PUBLICATION DATE

5-Oct-2023

 

AAAS launches STPF Rapid Response Cohort in AI to support policy development in Congress

Business Announcement

AMERICAN ASSOCIATION FOR THE ADVANCEMENT OF SCIENCE (AAAS)

The American Association for the Advancement of Science (AAAS) has conceived of and launched a new artificial intelligence (AI) fellowship in just two months — record speed — to support leaders in Congress as they craft legislation, in particular policies related to emerging opportunities and challenges with AI. Capitol Hill’s surging interest in AI policy follows the public release of ChatGPT and other generative AI tools.

The STPF Rapid Response Cohort in AI operates under the AAAS Science & Technology Policy Fellowships (STPF) program and is part of the 51st class of 276 scientists and engineers placed across all branches of the federal government who just kicked off their assignments. The AI cohort is comprised of six scientists who will serve as expert staff in a congressional office or committee with most starting their yearlong placements this week to provide guidance on pressing issues such as AI ethics, information integrity, intellectual property, human rights and algorithmic risk.

“We have been running the STPF program for half a century, and this is the first time we have been able to bring the support and a talented pool of applicants together in such a short timeframe. It took activating partners, scientific societies, industry colleagues and our networks to attract promising candidates and make this program a reality,” said Rashada Alexander, Ph.D., STPF director at AAAS. “Thanks to broad-base support, legislators can now more easily access AI-specific scientific and technical expertise as they explore policy options.”

The AI fellows were selected for their expertise and proficiency on the complexities of developing and deploying a multitude of AI technologies. They will help policymakers and their staff understand conceptually how AI works, along with the technical, economic and social issues that may arise from its widespread deployment. The AI fellows had two weeks to apply and two more weeks to wrap up their personal and professional lives — and, in most cases, move their households to Washington, D.C.

“The sudden explosion in generative AI affects every aspect of policy, from national security, workforce, and health care to intellectual property, education and transportation,” said Craig Mundie, former chief research and strategy officer for Microsoft, who conceived of this new fellowship cohort program with AAAS. “We are entering a transformational era in human history that requires informed policymakers who understand the potential implications of AI on society.”

Placements for the 2023-24 STPF Rapid Response Cohort in AI include: 

• U.S. Senate Committee on Banking, Housing, and Urban Affairs: Serena Booth, Ph.D., Computer Science, Massachusetts Institute of Technology. Prior positions: Visiting researcher at the University of Texas at Austin and product manager at Google. 
  • The committee scrutinizes AI, algorithms and other emerging technologies, which may be used in the banking, housing and investment fields.
• Office of Sen. Bill Cassidy (R-La.): Soribel Feliz, M.S., Public Administration and Economics, Syracuse University. Prior positions: Microsoft, Meta and the U.S. Department of State. 
  • Sen. Cassidy is a member of the U.S. Senate Committee on Health, Education, Labor & Pensions, which will cover AI impacts in health care, privacy, education and the workplace.
• Office of Sen. Martin Heinrich (D-N.M.): Cynthia Lee, Ph.D., Computer Science, University of California San Diego. Prior position: Faculty, Computer Science Department, Stanford University; has also served as an expert witness. 
  • Sen. Heinrich is co-chair of the Senate AI Caucus.
• Office of Sen. Mark Kelly (D-Ariz.): Kiri Wagstaff, Ph.D., Computer Science, Cornell University. Prior position: Senior Instructor I, Oregon State University, and the National Aeronautics and Space Administration.
  • Sen. Kelly is a member of the Senate AI Caucus.
• Office of Sen. Mike Rounds (R-S.D.): Rebecca Voglewede, Ph.D., Neuroscience, Tulane University. Prior position: National Institute on Deafness and Other Communication Disorders, National Institutes of Health.
  • Sen. Rounds is co-chair of the Senate AI Caucus.
• Office of Sen. Ron Wyden (D-Ore.): Eoghan Stafford, Ph.D., Political Science, University of California Los Angeles. Prior position: Centre for the Governance of AI (United Kingdom); researcher focused on the intersection of data science and human rights, democracy and international conflict. 
  • Sen. Wyden is focused on privacy, cybersecurity and other related issues to understand potentially abusive practices and advance national policy to prevent misuse.

“I am pleased to welcome Dr. Cynthia Bailey Lee to my team as a new AAAS fellow. Cynthia brings a wealth of computer science expertise, particularly in the area of artificial intelligence. She will be an important part of my team as the Senate continues to determine how best to govern AI,” said Sen. Heinrich.

Sen. Wyden added: “Eoghan's expertise on the intersection of AI and international human rights and free speech will provide a valuable new perspective to my office's work on those pressing issues. I look forward to Eoghan joining our team and contributing to the vital conversation about how to defend those core values in the face of rapid technological advancements.”

AAAS administers the STPF program, including the new AI cohort, and provides professional development throughout a fellow’s term. The selection process for STPF fellows is nonpartisan, and the fellows interview with host offices — personal offices and congressional committees — prior to making their final decisions. Of the 276 scientists and engineers in the 2023-24 STPF class, 38 are serving in Congress, one is serving at the Federal Judicial Center, and 237 are serving in the executive branch across 19 federal agencies or departments.

“These exceptional technology experts answered the call to help shape the future of AI. They will inform policy that enables the greatest AI advancements while ensuring benefits for all,” said Sudip S. Parikh, Ph.D., chief executive officer of AAAS. “As AAAS turns 175 and strives to ignite progress for the next two centuries, agile programs that provide timely expertise for urgent policy matters will be crucial — AI is just the beginning.”

AAAS received more than 130 applications for the AI cohort program from a wide range of scientists and engineers with AI-relevant expertise, who recognized the rare opportunity to serve in Congress during a pivotal time in the public policy landscape. The new AI fellowship class is sponsored by a funding consortium of foundations, corporations and individuals who recognize the need for AI technical expertise on Capitol Hill. For more information on the STPF program, visit this page.   

 

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The American Association for the Advancement of Science (AAAS) is the world’s largest general scientific society and publisher of the journal Science, as well as Science Translational Medicine; Science Signaling; a digital, open-access journal, Science Advances; Science Immunology; and Science Robotics. AAAS was founded in 1848 and includes more than 250 affiliated societies and academies of science, serving 10 million individuals. The nonprofit AAAS is open to all and fulfills its mission to “advance science and serve society” through initiatives in science policy, international programs, science education, public engagement, and more. For additional information about AAAS, visit www.aaas.org.

 

Founded in 1973, the AAAS Science & Technology Policy Fellowships (STPF) program provides opportunities to outstanding scientists and engineers to learn first-hand about policymaking and contribute their knowledge and analytical skills in the policy realm. As one of AAAS’ immersive fellowships, STPF aims to help ensure that public policy is made better and more complete with the consideration of scientific evidence. Fellows serve yearlong assignments in the federal government and represent a broad range of backgrounds, disciplines and career stages. Each year, STPF adds to a growing corps of approximately 4,000 policy-savvy leaders working across academia, government, nonprofits and industry to serve the nation and citizens around the world.

 

A cellulose-based thickener to reduce environmental risks of liquefied stabilized soil

Researchers show that adding a thickener can prevent bleeding, loss of fine particles, and unwanted settling of liquefied stabilized soil

Peer-Reviewed Publication

SHIBAURA INSTITUTE OF TECHNOLOGY

 

IMAGE: 

THE IMAGE SHOWS HOW LIQUEFIED STABILIZED SOIL CAN FIND USE AS A BACKFILL MATERIAL AT DIFFERENT LOCATIONS ON A CONSTRUCTION SITE.

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CREDIT: SHINYA INAZUMI FROM SHIBAURA INSTITUTE OF TECHNOLOGY, JAPAN IMAGE SOURCE: HTTPS://WWW.SCIENCEDIRECT.COM/SCIENCE/ARTICLE/PII/S2214509523005879?VIA%3DIHUB#COI0005

In many regions across the globe, rapid economic growth has increased the industrial waste generated from construction sites. The environmentally responsible disposal of this waste is a challenge. However, governments are now enacting stricter laws to prevent waste generation and ensure proper disposal of such waste. Popularized in the 1990s, liquefied soil stabilization is one approach to reuse excavated soil and harmful sludge at construction sites. The construction-generated waste is mixed with cement or other solidifying materials and reused as backfill for reinforcement and ground stabilization. The ability to pump and pour this material across a site is especially advantageous when applied in areas with constraints related to soil compaction that require rapid solidification.

Unfortunately, liquefied stabilized soil has drawbacks and isn’t environmentally friendly. First, “bleeding” can occur—when the water in the stabilized soil rises to the surface, and the denser materials settle to the bottom—which causes a loss in soil strength. Next, it cannot be poured over long distances due to fluidity constraints. Lastly, the cement solidifiers used during its preparation may contain chromium that can leach into the environment and cause heavy-metal contamination. A team of researchers at Shibaura Institute of Technology (SIT) has recently shown that altering the solidifiers and thickeners can help circumvent the existing structural and environmental limitations of liquefied stabilized soil. The team was led by Prof. Shinya Inazumi from the School of Engineering and Science at SIT, and their findings were made available online in Case Studies in Construction Materials on August 18, 2023.     

“Construction sludge and excavated soil has traditionally been considered waste, but its disposal bears an environmental cost. We are pursuing creative ways to regenerate this waste so it can serve as an environmentally friendly resource. Our geotechnical advancements have allowed us to tweak the liquefaction and stabilizing parameters to improve the soil’s characteristics,” says Prof. Inazumi, elaborating on the team’s motivation behind the research.

To overcome environmental and structural limitations, the team used a cellulose-based thickener to inhibit the bleeding phenomenon and maintain fluidity. Additionally, ordinary Portland cement (OPC) solidifier was replaced with a mixture of earth silica-blast furnace slag powder (ES-B). ES-B is more sustainable as it does not contain any chromium, its components can be altered to adjust the rate of curing, and when mixed with soil, it enables homogenous mixing and better fluidity of the end product. While the team studied how a solidifier with more ES-B and less OPC influenced soil characteristics, their main focus was understanding the impact of using a cellulose-based thickener.

The researchers found that strength of the liquefied stabilized soil  remained unaffected by the addition of the cellulose-based thickener, and was able to completely suppress bleeding and prevent the separation of soil components, compared to soil that didn’t incorporate a thickener. “While the soil’s fluidity did decrease, the cellulose-based thickener did not cause any difference in the reaction products nor resulted in the stabilized soil affecting its surroundings when immersed in water,” explained Prof. Inazumi when asked to elaborate on the study’s key findings.

These improvements to liquefied stabilized soils offer several advantages, which will help facilitate the environment-friendly disposal of industrial waste, but also improving the stability of building foundations—especially in earthquake-prone zones. The reuse of waste material will also improve the circularity of construction projects, resulting in cost savings and reduced environmental impact. This technology will also reduce the time needed for ground improvement on construction sites, improving operational efficiency.

 

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Reference

DOI: https://doi.org/10.1016/j.cscm.2023.e02407

 

About Shibaura Institute of Technology, Japan

Shibaura Institute of Technology (SIT) is a private university with campuses in Tokyo and Saitama. Since the establishment of its predecessor, the Tokyo Higher School of Industry and Commerce, in 1927, it has maintained “learning through practice” as its philosophy in the education of engineers. SIT was the only private science and engineering university selected for the Top Global University Project sponsored by the Ministry of Education, Culture, Sports, Science and Technology. The institute will receive support from the ministry for ten years starting from the 2014 academic year. Its motto, “Nurturing engineers who learn from society and contribute to society,” reflects its mission of fostering scientists and engineers who can contribute to the sustainable growth of the world by exposing their over 8,000 students to culturally diverse environments, where they learn to cope, collaborate, and relate with fellow students from around the world.

Website: https://www.shibaura-it.ac.jp/en/

 

About Professor Shinya Inazumi

Dr. Shinya Inazumi is a professor in the Department of Civil Engineering at Shibaura Institute of Technology. His laboratory researches ground improvement technologies for disaster management and environmental protection, damage to underground water resources following earthquakes, water-shielding technologies, and prolonging the life cycle of waste treatment plants. He has published over 90 peer-reviewed articles since 2000.

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JOURNAL

Case Studies in Construction Materials

DOI

10.1016/j.cscm.2023.e02407 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Experimental study on properties of liquefied stabilized soil produced with different types of solidifiers and thickeners