A tandem approach for better solar cells

KING ABDULLAH UNIVERSITY OF SCIENCE & TECHNOLOGY (KAUST)

 

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A REVIEW OF THE POTENTIAL OF COMBINING SILICON SOLAR CELLS WITH PEROVSKITE MATERIALS HIGHLIGHTS HOW TO SCALE UP THIS TECHNOLOGY.

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CREDIT: © 2024 KAUST; HENO HWANG.

Perovskite-based solar cells were first proved in 2009 to have excellent light-absorbing properties of methylammonium lead bromide and methylammonium lead iodide, collectively referred to as lead halide perovskites or, more simply, perovskites. While the efficiency of these first perovskite solar cells was modest, it was the start of a new path in photovoltaic research.

Today, it is clear that future solar cells are likely to include these perovskites in combination with traditional silicon. Erkan Aydin, Stefaan De Wolf and a team from KAUST have reviewed how this tandem technology can move out of the laboratory and be scaled up for commercial fabrication.[1]

The excitement over perovskites stems from the fact that they can be created at low temperatures and are easily deposited on most surfaces, including flexible ones, making them lighter, more adaptable and potentially cheaper than silicon solar panels.

“Both perovskite and silicon solar cells have proved to be highly efficient; however, using them both in tandem in a single cell enables better utilization of sunlight by minimizing the losses that are not converted to electrical charge,” says Aydin.

Aydin and his co-authors have charted the developments in tandem solar-cell fabrication that enable increases in size and power-conversion efficiency. But they highlight that other approaches are needed to make them commercially viable.

One challenge, for example, is that the topography of the silicon surface affects the deposition of the perovskite. The best-performing laboratory devices to date have used spin coating of a perovskite-precursor ink combined with an antisolvent treatment. However, this approach is not suited to commercial processing as it is hard to scale up and wastes a lot of material. Aydin and co-authors discuss the pros and cons of alternative approaches, such as slot-die coating and physical vapor deposition.

Another consideration is that moisture and heat and their combination with light accelerates the degradation of perovskite subcells. The authors detail various accelerated aging and real environment tests on perovskite/silicon tandem solar cells and underline the necessity of focused efforts in this direction. These help predict the reliability and lifetime of perovskite/silicon modules in a range of harsh environments.

“I think the biggest challenge is increasing the reliability of the perovskites subcells,” says Aydin. “Research activities we had so far have indicated that we have not yet reached any fundamental limit, so we need more concentrated effort to realize long-term stable devices.”

The proof-of-concept tandem modules have been introduced already. However, given the significant practical challenges, it is still unclear when perovskite/silicon tandems will reach market grade. However, the success in developing efficient commercial solar cells is vital for meeting the increasing demand for energy while reducing environmental impact.

 

REFERENCE

1. Aydin, E., Allen, T.B., De Bastiani, M., Razzaq, A., Xu, L., Ugur, E., Liu, J. & De Wolf, S. Pathways toward commercial perovskite/silicon tandem photovoltaics. Science 383, 162 (2024).| article

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JOURNAL

Science

DOI

10.1126/science.adh3849 

ARTICLE TITLE

Pathways toward commercial perovskite/silicon tandem photovoltaics

 

Two plant extracts with potential as GLP-1 agonist weight loss pills are identified by AI-based analysis

EUROPEAN ASSOCIATION FOR THE STUDY OF OBESITY

Two plant compounds with potential as GLP-1 agonist weight loss pills have been identified in an AI (artificial intelligence)-based study, the European Congress on Obesity (ECO 2024) (Venice 12-15 May), will hear.

Glucagon-like peptide-1 (GLP-1) receptor agonists such as semaglutide and tirzepatide are highly effective at helping people lose weight.  By mimicking the action of a hormone called GLP-1 and binding to and activating the GLP-1 receptor in cells, they reduce appetite and feelings of hunger, slow the release of food from the stomach and increase feelings of fullness after eating.

There is, however, a need for alternatives, says Elena Murcia, of the Structural Bioinformatics and High-Performance Computing Research Group (BIO-HPC) & Eating Disorders Research Unit, Catholic University of Murcia (UCAM), Murcia, Spain.

She explains: “Although the effectiveness of current GLP-1 agonists has been demonstrated, there are some side-effects associated with their use – gastrointestinal issues such as nausea, vomiting, and mental health changes like anxiety and irritability. Recent data has also confirmed that when patients stop treatment they regain lost weight.(1,2)

“In addition, most GLP-1 agonists are peptides – short chains of amino acids that can be degraded by stomach enzymes – and so they are currently more likely to be injected rather than taken orally.

“Drugs that aren't peptides may have fewer side-effects and be easier to administer, meaning they could be given as pills rather than injections. Other recent research has highlighted two promising non-peptide compounds, TTOAD2 and orforglipron.(3,4)

“These are synthetic and we were interested in finding natural alternatives.”

Ms Murcia and colleagues used high-performance artificial intelligence (AI) techniques to identify non-peptide natural compounds that activate the GLP-1 receptor.

“We focused on plant extracts and other natural compounds because they may have fewer side-effects,” says Ms Murcia. 

Virtual screening was used to sift through more than 10,000 compounds to identify those that bound to the GLP-1 receptor.

Next, further AI-based methods were used to look at how closely these bonds resembled those that occur between the GLP-1 hormone and its receptor. The 100 compounds that bound most similarly were then chosen for additional visual analysis, to determine whether they interacted with key residues – amino acids – on the receptor.

Finally, a Venn diagram (a mathematical graph using overlapping circles) was compiled to identify the compounds with the highest potential as GLP1-R agonists.

This resulted in a shortlist of 65 compounds, two of which, “Compound A” and “Compound B”, bound strongly to the key residues in a similar way to TTOAD2 and orforglipron. 

Compound A and Compound B are derived from very common plants, extracts of which have been associated with beneficial effects on the human metabolism in the past. Further details of the plants and the compounds are being kept confidential until patents are granted.  It is hoped both could be given in pill-form. The two compounds are now undergoing lab tests. 

Ms Murcia says: “We are in the early stages of developing new GLP-1 agonists derived from natural sources. If our AI-based calculations confirmed in vitro and then in clinical trials, we will have other therapeutic options to manage obesity. 

“Computer-based studies such as ours have key advantages, such as reductions in costs and time, rapid analysis of large data sets, flexibility in experimental design and the ability to identify and mitigate any ethical and safety risks before conducting experiments in the laboratory.

“These simulations also allow us to take advantage of AI resources to analyse complex problems and so provide a valuable initial perspective in the search for new drugs.”

Notes to editors:

References
1. Meier, J. J. Efficacy of Semaglutide in a Subcutaneous and an Oral Formulation. Front. Endocrinol. (Lausanne). 2021, 12. https://doi.org/10.3389/fendo.2021.645617

2. Tobaiqy, M., Elkout, H. Psychiatric adverse events associated with semaglutide, liraglutide and tirzepatide: a pharmacovigilance analysis of individual case safety reports submitted to the EudraVigilance database. Int J Clin Pharm (2024). https://doi.org/10.1007/s11096-023-01694-7
3. Zhao, P., Liang, YL., Belousoff, M.J. et al. Activation of the GLP-1 receptor by a non-peptidic agonist. Nature 577, 432-436 (2020). https://doi.org/10.1038/s41586-019-1902-z
4. Kawai T, Sun B, Yoshino H, Feng D, Suzuki Y, Fukazawa M, Nagao S, Wainscott DB, Showalter AD, Droz BA, Kobilka TS, Coghlan MP, Willard FS, Kawabe Y, Kobilka BK, Sloop KW. Structural basis for GLP-1 receptor activation by LY3502970, an orally active nonpeptide agonist. Proc Natl Acad Sci USA. 2020 Nov 24;117(47):29959-29967. https://doi.org/10.1073/pnas.201487911

 

 

 

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ARTICLE PUBLICATION DATE

26-Mar-2024

 

Nutritional rewards and risks revealed for edible seaweed around Hawaii

AMERICAN CHEMICAL SOCIETY

 

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SOME SEAWEEDS, LIKE THE ONE SHOWN HERE, ARE A SOURCE OF ESSENTIAL NUTRIENTS BUT MAY ALSO EXPOSE CONSUMERS TO UNSAFE LEVELS OF HEAVY METALS.

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CREDIT: ADAPTED FROM ACS FOOD SCIENCE & TECHNOLOGY 2024, DOI: 10.1021/ACSFOODSCITECH.3C00476

From sushi to soups, seaweed is a popular food around the world because it adds delicious flavors and beneficial nutrients to dishes. However, it might also expose consumers to heavy metals that accumulate in the fronds before they’re harvested. Given seaweed’s importance in the Hawaiian islands, a recent ACS Food Science & Technology publication reports a comprehensive analysis of essential nutrients and heavy metals for six species of seaweeds collected around Hawaii.

Seaweeds accumulate elements from the environment they’re grown in. Scientists know that factors such as the species or growing conditions impact the essential minerals, nutrients, and nonessential or toxic heavy metals in a serving of seaweed. However, not much is known about the balance of helpful versus potentially harmful compounds in many of the varieties traditionally eaten in Hawaii. Furthermore, the U.S. has not established safe regulatory limits for toxic substances such as arsenic and lead in whole pieces of edible seaweed, meaning that some products available for sale may not be tested for these compounds. So, Kacie Ho and colleagues decided to analyze key nutrients and metals in seaweed species grown around Hawaii.

The researchers obtained six types of seaweed that were either cultivated or collected in the wild. They measured the beneficial nutrients and toxic elements in each species and used statistics to differentiate between samples. They found that:

• Four of the six tested seaweeds were excellent sources of at least one essential mineral — with greater than 20% of the recommended daily value per serving of either iron, manganese, or both calcium and magnesium.
• The amounts of protein, fat, carbohydrates and fiber varied significantly across the tested species, and generally aligned with previous nutritional assessments for three of the seaweeds.
• Two wild species that are not commonly consumed, S. aquifolium and S. echinocarpum, had the highest levels of arsenic-containing compounds — far exceeding safe consumption limits established by other countries.
• Two farmed species, H. formosa and G. parvispora, contained elevated lead levels, which are above those recommended for safe eating in Taiwan.

Overall, the researchers found that Hawaiian seaweeds provide many essential minerals and nutrients, but may also expose consumers to unsafe levels of heavy metals, depending on factors such as seaweed type and growing conditions. Previously published studies suggested that boiling or rinsing other seaweed species, which weren’t included in this work, could remove some harmful substances. But these techniques may also strip away beneficial nutrients. So, Ho and colleagues are collaborating with seaweed growers to study the impact of growing location and common cooking practices on levels of heavy metals and nutrients in Hawaiian seaweeds. Their findings could inform future regulations and ensure nutritious and safe seaweed food products.

The authors acknowledge funding from the United States Department of Agriculture’s National Institute of Food and Agriculture, Multistate Project.

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The American Chemical Society (ACS) is a nonprofit organization chartered by the U.S. Congress. ACS’ mission is to advance the broader chemistry enterprise and its practitioners for the benefit of Earth and all its people. The Society is a global leader in promoting excellence in science education and providing access to chemistry-related information and research through its multiple research solutions, peer-reviewed journals, scientific conferences, eBooks and weekly news periodical Chemical & Engineering News. ACS journals are among the most cited, most trusted and most read within the scientific literature; however, ACS itself does not conduct chemical research. As a leader in scientific information solutions, its CAS division partners with global innovators to accelerate breakthroughs by curating, connecting and analyzing the world’s scientific knowledge. ACS’ main offices are in Washington, D.C., and Columbus, Ohio.

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JOURNAL

ACS Food Science & Technology

DOI

10.1021/acsfoodscitech.3c00476 

ARTICLE TITLE

Determination of the Nutrient and Toxic Element Content of Wild-Collected and Cultivated Seaweeds from Hawai‘i

 POSTMODERN MINERAL ALCHEMY

NHM scientists discover first-ever mineral-based treatment for widespread disease using the structure of crystals

Based on the structure of cubic zirconium silicate, the innovative treatment opens doors to future mineral-based treatments made possible by cutting-edge museum science

NATURAL HISTORY MUSEUM OF LOS ANGELES COUNTY

 

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FIG 18 FROM THE STUDY. AN ILLUSTRATION OF PART OF A 3MR SHOWING HOW THE DOUBLE LEVER MECHANISMS WORKS IN CZS-(NA,H).

 

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CREDIT: JASON LIVELY, AARON J. CELESTIAN

Los Angeles, CA (March 26, 2024) — In a ground breaking discovery, scientists at the Natural History Museum of Los Angeles County and pharmaceutical firm AstraZeneca have published the first-ever mineral-based treatment for a widespread disease. Reported in the journal PLOS One, the study by mineralogist Dr. Aaron Celestian, Curator of Mineral Sciences at NHM, and pharmaceutical chemist  Dr. Jason Lively, opens the door to more advanced mineral-based treatments in the future.

The paper describes how crystals have been used as a new treatment for hyperkalemia, a disease that affects roughly 350 million people across the planet. Hyperkalemia strikes when a person has too much potassium in their blood and cannot regulate potassium levels. It can result in cardiac arrest in acute cases or cause kidney and liver dysfunction or failure in persistent cases that last decades. 

“For people suffering from hyperkalemia, the biological processes that regulate potassium in the body are not working optimally, so they have to constantly manage their condition through medications that have potentially harmful side effects and dietary restrictions,” says Celestian. 

The new treatment lets patients flush the excess potassium through ion transfer. “The crystals find the potassium,  absorb it, and then excess gets filtered out of the body through the kidneys,”  says Celestian.

The researchers used the crystal structure of cubic zirconium silicate to develop a treatment without harmful biological interaction—and associated negative side effects.  This is a new way to alleviate deleterious effects on patients that other treatments have.

“It’s like material engineering using minerals as a template,” says Celestian. “Nature’s already grown incredible tools for treating illnesses, and we’re only just beginning to harness those tools.”

Besides having significantly less biological interaction, mineral-based therapies might offer the chance for more durable treatments. Using the structure of crystals means that similar treatments could potentially overcome mutations that make things like viruses so difficult to treat effectively. 

“Minerals probably don’t care about how a virus mutates, as long as it has those building block proteins that the mineral likes to interact with,” says Celestian.

 Cubic zirconium crystal structures examined under the Scanning Electron Microscope

CREDIT

Aaron Celestian

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JOURNAL

PLoS ONE

DOI

10.1371/journal.pone.0298661 

METHOD OF RESEARCH

Experimental study

ARTICLE TITLE

In situ potassium and hydrogen ion exchange into a cubic zirconium silicate microporous material

ARTICLE PUBLICATION DATE

21-Mar-2024

COI STATEMENT

Author J. Lively is employed by AstraZeneca at the time of publication. This work received partial financial support from ZS Pharma (subsequently acquired by AstraZeneca). Additional financial support was received from the John Jago Trelawney and Bandy Endowments to the Natural History Museum Mineral Sciences Department. This research used resources of the Advanced Photon Source, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357.

 

£69 million boost for hydrogen at Cranfield

Cranfield University will spearhead the research and development of the first major hydrogen technology hub to demonstrate the potential of hydrogen as a net zero aviation fuel.

CRANFIELD UNIVERSITY

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• Largest ever research funding win for Cranfield University
• Investment heralds a ‘step change’ in hydrogen research, developing the first large scale hydrogen research hub at any UK airport
• Funding will unlock technical challenges and scale-up hydrogen-enabled aviation to help meet net zero emissions targets

Cranfield University will spearhead the research and development of the first major hydrogen technology hub to demonstrate the potential of hydrogen as a net zero aviation fuel.

The £69 million investment creating the Cranfield Hydrogen Integration Incubator (CH2i) is the largest financial injection for research that Cranfield University has ever secured. £23 million comes from Research England’s Research Partnership Investment Fund (UKRPIF), with a further £46 million committed from industry partners and academic institutions.

The demand for air travel is rising, with estimates that UK passenger traffic could increase from 284 million in 2016 to 435 million by 2050. Unless action is taken, aviation will be the largest source of carbon greenhouse gas emissions by the middle of the century. In this context, the rapid development and scale up of hydrogen-enabled aviation is a critical part of addressing growing demands whist transitioning to cleaner air transport. With domestic aviation set a target of achieving net zero emissions by 2040 in the UK government’s Jet Zero strategy, CH2i will support the aviation industry to explore how to move towards the use of hydrogen at scale.

“This game-changing investment builds on Cranfield’s expertise in hydrogen research and will help the aviation industry to make the leap to using hydrogen,” said Professor Karen Holford CBE FREng, Chief Executive and Vice-Chancellor of Cranfield University.

“CH2i will integrate with other large industry research areas at Cranfield including our novel hydrogen production programmes and our Aerospace Integration Research Centre and the Digital Aviation Research and Technology Centre. Working with research and industry partners nationally and internationally, we will unlock some of the most significant technical challenges around the future development and deployment of hydrogen in aviation. It’s a very exciting prospect for our researchers, partners and for the aviation industry. It will help to build the pathway to net zero emissions aviation.”

New hydrogen ecosystem to rapidly develop technology for a sustainable future

CH2i will create a unique ecosystem at Cranfield, connecting the production, integration and use of hydrogen for net zero aviation, proving how the industry can decarbonise rapidly.

The research collaboration, linking into a new Centre for Doctoral Training in Net Zero Aviation at Cranfield, will provide an environment to develop the production technologies, catalysts, materials, structures, storage tanks, aircraft designs and engines that are urgently required to accelerate the adoption of hydrogen in a net zero world. By developing new laboratories, at scale test facilities and airport infrastructure this project will deliver a transformation in hydrogen technologies.

Bringing together academia, industry, government and regulatory authorities, CH2i’s work will inform policies, services and regulatory practices that are needed to realise regional, national and international economic growth and skills development opportunities.

Co-Principal Investigator of CH2i, Professor Dame Helen Atkinson DBE FREng, Pro-Vice-Chancellor and Head of the School for Aerospace, Transport and Manufacturing and Materials: “The consortium will bring a ‘systems engineering’ approach, accelerating the integration of hydrogen into airports and aerospace propulsion and delivering next generation technologies. Together we are committed to unlocking hydrogen’s potential for airports and aviation globally, realising our collective ambitions for a more sustainable future.”

Investment to enable development across whole supply chain

As the only university in Europe with its own airport, research aircraft and air traffic control facilities, Cranfield has a controlled airside environment which can demonstrate, test and advance new technologies, systems and processes at scale.

Co-Principal Investigator of CH2i, Professor Chris Fogwill, Pro-Vice-Chancellor and Head of School for Water, Energy and Environment at Cranfield University said: “We’re creating the blueprint for sustainable zero emissions flight and infrastructure, by building world-class laboratory and test facilities that integrate the production, storage and utilisation of hydrogen at scale across the campus and airport.”

CH2i will connect and expand existing facilities at Cranfield, supporting research and development across the whole supply chain from production, storage, transport and usage, through to assessment of the environmental impacts. CH2i will demonstrate where hydrogen can be integrated into both ground operations and as a fuel for aircraft propulsion.

CH2i will include three large infrastructure elements:

1. Hydrogen Integration Research Centre – extending an existing facility, this will include new labs for advanced materials synthesis and testing for hydrogen-based technologies, analytical laboratories and a dedicated innovation area to develop next generation hydrogen pilot plant demonstration, electrolysis, catalyst development and green hydrogen.

2. Enabling Hydrogen Innovation (Test Area) - investment into two separate test bed facilities, able to support hydrogen and liquid hydrogen activity, fuel systems, storage and propulsion system integration at mid- and high-technology readiness levels.

3. Development of Cranfield Airport’s infrastructure, increasing its capability for safe operation and testing of future demonstrator hydrogen-powered aviation.

The funding will also provide new equipment, project management and staffing to support the project.

Track record in safe developments for industrial use

“A key part of this initiative is achieving rapid innovation within a regulated, safety-critical context,” commented Professor Leon A. Terry, Pro-Vice-Chancellor for Research and Innovation at Cranfield University.

“Cranfield has existing expertise in the production, storage and use of hydrogen in an industrial context, and a track record of building near-industrial scale facilities. This funding heralds a transformation in the hydrogen research trajectory, and our unique expertise and facilities puts Cranfield right at the centre of accelerating hydrogen development in the UK.”

Building capability for the UK and industry

Professor Sir Iain Gray, Director of Aerospace at Cranfield University and a member of the UK Jet Zero Council, noted that new business opportunities will emerge: “CH2i is set to act as a global and regional incubator for sustainable aviation research and innovation. It builds on our strategic relationships with industry and will create an environment where we can openly explore how hydrogen innovations will change aviation. It will also stimulate new business opportunities across the aviation supply chain and help to provide a new talent pipeline of researchers to grow a competitive high technology capability for the UK.”

Marshall CEO Kathy Jenkins commented: “This investment in CH2i is a clear vote of confidence in Cranfield’s unique position as a scientific and industrial flagship for the UK. It demonstrates hydrogen’s transformative potential in aviation. As we continue to advance our strategic relationship with Cranfield, these test facilities will serve as an ideal proving ground for our newly established HyFIVE consortium. It is here we will develop globally outstanding hydrogen technologies and products that support clean growth and future mobility.”

Cranfield Aerospace Solutions CEO, Paul Hutton said: “CAeS welcomes the establishment of the CH2i hydrogen hub at Cranfield and is proud to be a major industrial partner in the programme. The investment will provide valuable facilities for our hydrogen fuel cell propulsion system development programme and we look forward to deepening our relationship with the Cranfield University team as we develop the technology needed for a more sustainable aviation industry."

£1 billion investment since funding scheme began

The investment from Research England brings the total funding figure for the RPIF scheme to £1 billion since its inception. Cranfield is one of four universities to receive funding in this round.

Professor Dame Jessica Corner, Executive Chair at Research England, said:“I am pleased to be able to award four more universities funding from our flagship UK Research Partnership Investment Fund to create four centres in a diverse range of topics, from net zero aviation to wound research, and disease therapies to future transport.

“The fact that we have been able to fund 60 research centres and facilities from the fund since 2012, investing £1 billion to tackle some of today’s biggest research challenges, from developing treatments for Parkinson’s and Alzheimer’s disease to tackling global inequalities, and finding better treatments for cancer to net zero growth, is something I am immensely proud of.

“I very much look forward to seeing how these new facilities deliver against a variety of diverse challenges over the coming years.”

Project partners

Research and industry partners who are co-investors for the project include:

• Marshall
• Cranfield Aerospace Solutions
• GKN Aerospace
• AIRBUS
• Element 2
• Hywaves
• Toyota
• GTI Energy
• Siemens Energy
• Heathrow Airport
• Modular Clinton Global
• Equilibrion

Academic partners include:

• Imperial College London
• Midlands Innovation Energy Research Accelerator (ERA)
• UKRI NERC National Centre for Atmospheric Science
• UK Aerospace Research Consortium
• UK Collaboration for Research on Infrastructure and Cities (UKCRIC)
• National Physical Laboratory (NPL)

 

MIT-derived algorithm helps forecast the frequency of extreme weather

The new approach “nudges” existing climate simulations closer to future reality

MASSACHUSETTS INSTITUTE OF TECHNOLOGY

To assess a community’s risk of extreme weather, policymakers rely first on global climate models that can be run decades, and even centuries, forward in time, but only at a coarse resolution. These models might be used to gauge, for instance, future climate conditions for the northeastern U.S., but not specifically for Boston. 

To estimate Boston’s future risk of extreme weather such as flooding, policymakers can combine a coarse model’s large-scale predictions with a finer-resolution model, tuned to estimate how often Boston is likely to experience damaging floods as the climate warms. But this risk analysis is only as accurate as the predictions from that first, coarser climate model. 

“If you get those wrong for large-scale environments, then you miss everything in terms of what extreme events will look like at smaller scales, such as over individual cities,” says Themistoklis Sapsis, the William I. Koch Professor and director of the Center for Ocean Engineering in MIT’s Department of Mechanical Engineering. 

Sapsis and his colleagues have now developed a method to “correct” the predictions from coarse climate models. By combining machine learning with dynamical systems theory, the team’s approach “nudges” a climate model’s simulations into more realistic patterns over large scales. When paired with smaller-scale models to predict specific weather events such as tropical cyclones or floods, the team’s approach produced more accurate predictions for how often specific locations will experience those events over the next few decades, compared to predictions made without the correction scheme. 

Sapsis says the new correction scheme is general in form and can be applied to any global climate model. Once corrected, the models can help to determine where and how often extreme weather will strike as global temperatures rise over the coming years.  

“Climate change will have an effect on every aspect of human life, and every type of life on the planet, from biodiversity to food security to the economy,” Sapsis says. “If we have capabilities to know accurately how extreme weather will change, especially over specific locations, it can make a lot of difference in terms of preparation and doing the right engineering to come up with solutions. This is the method that can open the way to do that.”

The team’s results appear today in the Journal of Advances in Modeling Earth Systems. The study’s MIT co-authors include postdoc Benedikt Barthel Sorensen and Alexis-Tzianni Charalampopoulos SM ’19, PhD ’23, with Shixuan Zhang, Bryce Harrop, and Ruby Leung of the Pacific Northwest National Laboratory in Washington state.

Over the hood

Today’s large-scale climate models simulate weather features such as the average temperature, humidity, and precipitation around the world, on a grid-by-grid basis. Running simulations of these models takes enormous computing power, and in order to simulate how weather features will interact and evolve over periods of decades or longer, models average out features every 100 kilometers or so. 

“It’s a very heavy computation requiring supercomputers,” Sapsis notes. “But these models still do not resolve very important processes like clouds or storms, which occur over smaller scales of a kilometer or less.”

To improve the resolution of these coarse climate models, scientists typically have gone under the hood to try and fix a model’s underlying dynamical equations, which describe how phenomena in the atmosphere and oceans should physically interact. 

“People have tried to dissect into climate model codes that have been developed over the last 20 to 30 years, which is a nightmare, because you can lose a lot of stability in your simulation,” Sapsis explains. “What we’re doing is a completely different approach, in that we’re not trying to correct the equations but instead correct the model’s output.”

The team’s new approach takes a model’s output, or simulation, and overlays an algorithm that nudges the simulation toward something that more closely represents real-world conditions. The algorithm is based on a machine-learning scheme that takes in data, such as past information for temperature and humidity around the world, and learns associations within the data that represent fundamental dynamics among weather features. The algorithm then uses these learned associations to correct a model’s predictions.

“What we’re doing is trying to correct dynamics, as in how an extreme weather feature, such as the windspeeds during a Hurricane Sandy event, will look like in the coarse model, versus in reality,” Sapsis says. “The method learns dynamics, and dynamics are universal. Having the correct dynamics eventually leads to correct statistics, for example, frequency of rare extreme events.”

Climate correction

As a first test of their new approach, the team used the machine-learning scheme to correct simulations produced by the Energy Exascale Earth System Model (E3SM), a climate model run by the U.S. Department of Energy, that simulates climate patterns around the world  at a resolution of 110 kilometers. The researchers used eight years of past data for temperature, humidity, and wind speed to train their new algorithm, which learned dynamical associations between the measured weather features and the E3SM model. They then ran the climate model forward in time for about 36 years and applied the trained algorithm to the model’s simulations. They found that the corrected version produced climate patterns that more closely matched real-world observations from the last 36 years, not used for training. 

 

“We’re not talking about huge differences in absolute terms,” Sapsis says. “An extreme event in the uncorrected simulation might be 105 degrees Fahrenheit, versus 115 degrees with our corrections. But for humans experiencing this, that is a big difference.”

When the team then paired the corrected coarse model with a specific, finer-resolution model of tropical cyclones, they found the approach accurately reproduced the frequency of extreme storms in specific locations around the world. 

“We now have a coarse model that can get you the right frequency of events, for the present climate. It’s much more improved,” Sapsis says. “Once we correct the dynamics, this is a relevant correction, even when you have a different average global temperature, and it can be used for understanding how forest fires, flooding events, and heat waves will look in a future climate. Our ongoing work is focusing on analyzing future climate scenarios.”

This work was supported, in part, by the U.S. Defense Advanced Research Projects Agency.

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Written by Jennifer Chu, MIT News

Paper: “A non-intrusive machine learning framework for debiasing long-time coarse resolution climate simulations and quantifying rare events statistics”

https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2023MS004122

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JOURNAL

Journal of Advances in Modeling Earth Systems

DOI

10.1029/2023MS004122 

ARTICLE TITLE

“A non-intrusive machine learning framework for debiasing long-time coarse resolution climate simulations and quantifying rare events statistics”

 

Artificial reef designed by MIT engineers could protect marine life, reduce storm damage

The sustainable and cost-saving structure could dissipate more than 95 percent of incoming wave energy using a small fraction of the material normally needed

MASSACHUSETTS INSTITUTE OF TECHNOLOGY

 

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AN MIT TEAM IS HOPING TO FORTIFY COASTLINES WITH “ARCHITECTED” REEFS — SUSTAINABLE, OFFSHORE STRUCTURES THAT ARE ENGINEERED TO MIMIC THE WAVE-BUFFERING EFFECTS OF NATURAL REEFS WHILE ALSO PROVIDING POCKETS FOR FISH AND OTHER MARINE LIFE TO LIVE.

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CREDIT: COURTESY OF MICHAEL TRIANTAFYLLOU, ET AL

The beautiful, gnarled, nooked-and-crannied reefs that surround tropical islands serve as a marine refuge and natural buffer against stormy seas. But as the effects of climate change bleach and break down coral reefs around the world, and extreme weather events become more common, coastal communities are left increasingly vulnerable to frequent flooding and erosion. 

An MIT team is now hoping to fortify coastlines with “architected” reefs — sustainable, offshore structures engineered to mimic the wave-buffering effects of natural reefs while also providing pockets for fish and other marine life. 

The team’s reef design centers on a cylindrical structure surrounded by four rudder-like slats. The engineers found that when this structure stands up against a wave, it efficiently breaks the wave into turbulent jets that ultimately dissipate most of the wave’s total energy. The team has calculated that the new design could reduce as much wave energy as existing artificial reefs, using 10 times less material.

The researchers plan to fabricate each cylindrical structure from sustainable cement, which they would mold in a pattern of “voxels” that could be automatically assembled, and would provide pockets for fish to explore and other marine life to settle in. The cylinders could be connected to form a long, semipermeable wall, which the engineers could erect along a coastline, about half a mile from shore. Based on the team’s initial experiments with lab-scale prototypes, the architected reef could reduce the energy of incoming waves by more than 95 percent.

“This would be like a long wave-breaker,” says Michael Triantafyllou, the Henry L. and Grace Doherty Professor in Ocean Science and Engineering in the Department of Mechanical Engineering. “If waves are 6 meters high coming toward this reef structure, they would be ultimately less than a meter high on the other side. So, this kills the impact of the waves, which could prevent erosion and flooding.”

Details of the architected reef design are reported today in a study appearing in the open-access journal PNAS Nexus. Triantafyllou’s MIT co-authors are Edvard Ronglan SM ’23; graduate students Alfonso Parra Rubio, Jose del Auila Ferrandis, and Erik Strand; research scientists Patricia Maria Stathatou and Carolina Bastidas; and Professor Neil Gershenfeld, director of the Center for Bits and Atoms; along with Alexis Oliveira Da Silva at the Polytechnic Institute of Paris, Dixia Fan of Westlake University, and Jeffrey Gair Jr. of Scinetics, Inc.

Leveraging turbulence

Some regions have already erected artificial reefs to protect their coastlines from encroaching storms. These structures are typically sunken ships, retired oil and gas platforms, and even assembled configurations of concrete, metal, tires, and stones. However, there’s variability in the types of artificial reefs that are currently in place, and no standard for engineering such structures. What’s more, the designs that are deployed tend to have a low wave dissipation per unit volume of material used. That is, it takes a huge amount of material to break enough wave energy to adequately protect coastal communities. 

The MIT team instead looked for ways to engineer an artificial reef that would efficiently dissipate wave energy with less material, while also providing a refuge for fish living along any vulnerable coast. 

“Remember, natural coral reefs are only found in tropical waters,” says Triantafyllou, who is director of the MIT Sea Grant. “We cannot have these reefs, for instance, in Massachusetts. But architected reefs don’t depend on temperature, so they can be placed in any water, to protect more coastal areas.”

The new effort is the result of a collaboration between researchers in MIT Sea Grant, who developed the reef structure’s hydrodynamic design, and researchers at the Center for Bits and Atoms (CBA), who worked to make the structure modular and easy to fabricate on location. The team’s architected reef design grew out of two seemingly unrelated problems. CBA researchers were developing ultralight cellular structures for the aerospace industry, while Sea Grant researchers were assessing the performance of blowout preventers in offshore oil structures — cylindrical valves that are used to seal off oil and gas wells and prevent them from leaking.

The team’s tests showed that the structure’s cylindrical arrangement generated a high amount of drag. In other words, the structure appeared to be especially efficient in dissipating high-force flows of oil and gas. They wondered: Could the same arrangement dissipate another type of flow, in ocean waves?

The researchers began to play with the general structure in simulations of water flow, tweaking its dimensions and adding certain elements to see whether and how waves changed as they crashed against each simulated design. This iterative process ultimately landed on an optimized geometry: a vertical cylinder flanked by four long slats, each attached to the cylinder in a way that leaves space for water to flow through the resulting structure. They found this setup essentially breaks up any incoming wave energy, causing parts of the wave-induced flow to spiral to the sides rather than crashing ahead. 

“We’re leveraging this turbulence and these powerful jets to ultimately dissipate wave energy,” Ferrandis says.

Standing up to storms

Once the researchers identified an optimal wave-dissipating structure, they fabricated a laboratory-scale version of an architected reef made from a series of the cylindrical structures, which they 3D-printed from plastic. Each test cylinder measured about 1 foot wide and 4 feet tall. They assembled a number of cylinders, each spaced about a foot apart, to form a fence-like structure, which they then lowered into a wave tank at MIT. They then generated waves of various heights and measured them before and after passing through the architected reef. 

“We saw the waves reduce substantially, as the reef destroyed their energy,” Triantafyllou says. 

The team has also looked into making the structures more porous, and friendly to fish. They found that, rather than making each structure from a solid slab of plastic, they could use a more affordable and sustainable type of cement. 

“We’ve worked with biologists to test the cement we intend to use, and it’s benign to fish, and ready to go,” he adds.

They identified an ideal pattern of “voxels,” or microstructures, that cement could be molded into, in order to fabricate the reefs while creating pockets in which fish could live. This voxel geometry resembles individual egg cartons, stacked end to end, and appears to not affect the structure’s overall wave-dissipating power.

“These voxels still maintain a big drag while allowing fish to move inside,” Ferrandis says. 

The team is currently fabricating cement voxel structures and assembling them into a lab-scale architected reef, which they will test under various wave conditions. They envision that the voxel design could be modular, and scalable to any desired size, and easy to transport and install in various offshore locations. “Now we’re simulating actual sea patterns, and testing how these models will perform when we eventually have to deploy them,” says Anjali Sinha, a graduate student at MIT who recently joined the group. 

Going forward, the team hopes to work with beach towns in Massachusetts to test the structures on a pilot scale. 

“These test structures would not be small,” Triantafyllou emphasizes. “They would be about a mile long, and about 5 meters tall, and would cost something like 6 million dollars per mile. So it’s not cheap. But it could prevent billions of dollars in storm damage. And with climate change, protecting the coasts will become a big issue.”

This work was funded, in part, by the U.S. Defense Advanced Research Projects Agency.

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Written by Jennifer Chu, MIT News

Paper: “Architected Materials for Artificial Reefs to Increase Storm Energy Dissipation”

https://academic.oup.com/pnasnexus/article/3/3/pgae101/7631220

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JOURNAL

PNAS Nexus

DOI

10.1093/pnasnexus/pgae101 

ARTICLE TITLE

“Architected Materials for Artificial Reefs to Increase Storm Energy Dissipation”