New material offers ecofriendly solution to converting waste heat into energy

by Northwestern University

Credit: Unsplash/CC0 Public Domain

Perseverance, NASA's 2020 Mars rover, is powered by something very desirable here on Earth: a thermoelectric device, which converts heat to useful electricity.

On Mars, the heat source is the radioactive decay of plutonium, and the device's conversion efficiency is 4-5%. That's good enough to power Perseverance and its operations but not quite good enough for applications on Earth.

A team of scientists from Northwestern University and Seoul National University in Korea now has demonstrated a high-performing thermoelectric material in a practical form that can be used in device development. The material—purified tin selenide in polycrystalline form—outperforms the single-crystal form in converting heat to electricity, making it the most efficient thermoelectric system on record. The researchers were able to achieve the high conversion rate after identifying and removing an oxidation problem that had degraded performance in earlier studies.

The polycrystalline tin selenide could be developed for use in solid-state thermoelectric devices in a variety of industries, with potentially enormous energy savings. A key application target is capturing industrial waste heat—such as from power plants, the automobile industry and glass- and brick-making factories—and converting it to electricity. More than 65% of the energy produced globally from fossil fuels is lost as waste heat.

"Thermoelectric devices are in use, but only in niche applications, such as in the Mars rover," said Northwestern's Mercouri Kanatzidis, a chemist who specializes in the design of new materials. "These devices have not caught on like solar cells, and there are significant challenges to making good ones. We are focusing on developing a material that would be low cost and high performance and propel thermoelectric devices into more widespread application."

Kanatzidis, the Charles E. and Emma H. Morrison Professor of Chemistry in the Weinberg College of Arts and Sciences, is a co-corresponding author of the study. He has a joint appointment with ArgonneNational Laboratory.

Details of the thermoelectric material and its record-high performance will be published Aug. 2 in the journal Nature Materials.

In Chung of Seoul National University is the paper's other co-corresponding author. Vinayak Dravid,the Abraham Harris Professor of Materials Science and Engineering at Northwestern's McCormick School of Engineering,is one of the study's senior authors. Dravid is a long-time collaborator of Kanatzidis'.

Thermoelectric devices are already well defined, says Kanatzidis, but what makes them work well or not is the thermoelectric material inside. One side of the device is hot and the other side cold. The thermoelectric material lies in the middle. Heat flows through the material, and some of the heat is converted to electricity, which leaves the device via wires.

The material needs to have extremely low thermal conductivity while still retaining good electrical conductivity to be efficient at waste heat conversion. And because the heat source could be as high as 400-500 degrees Celsius, the material needs to be stable at very high temperatures. These challenges and others make thermoelectric devices more difficult to produce than solar cells.

'Something diabolical was happening'

In 2014, Kanatzidis and his team reported the discovery of a surprising material that was the best in the world at converting waste heat to useful electricity: the crystal form of the chemical compound tin selenide. While an important discovery, the single-crystal form is impractical for mass production because of its fragility and tendency to flake.

Tin selenide in polycrystalline form, which is stronger and can be cut and shaped for applications, was needed, so the researchers turned to studying the material in that form. In an unpleasant surprise, they found the material's thermal conductivity was high, not the desirable low level found in the single-crystal form.

"We realized something diabolical was happening," Kanatzidis said. "The expectation was that tin selenide in polycrystalline form would not have high thermal conductivity, but it did. We had a problem."

Upon closer examination, the researchers discovered a skin of oxidized tin on the material. Heat flowed through the conductive skin, increasing the thermal conductivity, which is undesirable in a thermoelectric device.

A solution is found, opening doors

After learning that the oxidation came from both the process itself and the starting materials, the Korean team found a way to remove the oxygen. The researchers then could produce tin selenide pellets with no oxygen, which they then tested.

The true thermal conductivity of the polycrystalline form was measured and found to be lower, as originally expected. Its performance as a thermoelectric device, converting heat to electricity, exceeded that of the single crystal form, making it the most efficient on record.

The efficiency of waste heat conversion in thermoelectrics is reflected by its "figure of merit," a number called ZT. The higher the number, the better the conversion rate. The ZT of single-crystal tin selenide earlier was found to be approximately 2.2 to 2.6 at 913 Kelvin. In this new study, the researchers found the purified tin selenide in polycrystalline form had a ZT of approximately 3.1 at 783 Kelvin. Its thermal conductivity was ultralow, lower than the single-crystals.

"This opens the door for new devices to be built from polycrystalline tin selenide pellets and their applications explored," Kanatzidis said.

Northwestern owns the intellectual property for the tin selenide material. Potential areas of application for the thermoelectric material include the automobile industry (a significant amount of gasoline's potential energy goes out of a vehicle's tailpipe), heavy manufacturing industries (such as glass and brick making, refineries, coal- and gas-fired power plants) and places where large combustion engines operate continuously (such as in large ships and tankers).

The title of the paper is "Polycrystalline SnSe with a thermoelectric figure of merit greater than the single-crystal."

Development of a novel thermoelectric material with record-high conversion efficiency

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More information: Polycrystalline SnSe with a thermoelectric figure of merit greater than the single crystal, Nature Materials (2021). DOI: 10.1038/s41563-021-01064-6 , www.nature.com/articles/s41563-021-01064-6

Journal information: Nature Materials 

Provided by Northwestern University 

Salmon are getting cooked by climate change. Here's how they could be saved

Both Pacific and Atlantic salmon at risk from climate change impacts, but habitat tweaks could help

Emily Chung · CBC News · Posted: Jul 23, 2021 

A dead chinook salmon floats in a fish trap on the lower Klamath River in Weitchpec, Calif., in June. A historic drought and low water levels on the Klamath River are threatening the existence of fish species along the 413-kilometre long river. But heat and drought also threaten salmon on both of Canada's coasts. (Nathan Howard/The Associated Press)

A heat wave is expected to kill all juvenile chinook salmon in California's Sacramento River, wildlife officials say. Meanwhile, climate change and extreme heat waves are hitting Canada's salmon too, on both coasts.

So, how bad is it here, and what can be done to save our salmon? CBC News explains.
What's happening to salmon in California?

California's Department of Fish and Wildlife warned last week that among chinook salmon in the Sacramento River "it is possible that all in-river juveniles will not survive this season." That was due to a heat wave that pushed local temperatures above 37 C, combined with a drought that caused more water to be diverted to cities and farmers, making the river shallower and quick to heat up.

Has that kind of thing happened further north?

There are some reports of it happening amid this year's record-breaking heat wave in B.C. The B.C. Wildlife Federation reports that the Okanagan River was more than 23 C this week, causing sockeye salmon to halt their migration.

"There's a good chance the run will be ... doomed by heat," said Jesse Zeman, director of the federation's fish and wildlife restoration program.

In 2016, warm temperatures were blamed for the lowest number of returning sockeye in B.C.'s Fraser River on record, and two years later, officials warned that the river was so warm that migrating sockeye salmon might die on their journey. In 2019, there were heat-related salmon die-offs blamed in Alaska and at a fish farm in Newfoundland.

WATCH | Team surveys dead salmon on Alaska river:



Team surveys dead salmon on Alaska River2 years ago
2:18 A team from the Yukon River Inter-Tribal Fish Commission in Alaska surveys dead chum salmon on the Koyukuk River in July. 

But salmon deaths due to heat aren't necessarily sudden and noticeable. Many populations of both Pacific and Atlantic salmon have been in gradual decline for decades, and scientists say warmer temperatures and other aspects of climate change have played a role.

Atlantic salmon in eastern Cape Breton could be added to list of species at risk

New research suggests 70% decline in diversity of B.C. sockeye salmon stock in past century

How do warm temperatures harm or kill salmon?

Both Atlantic and Pacific salmon are cold-water fish, which means they tend to do best at temperatures in the mid-teens and struggle when it's over 20 C.

Warm water can harm salmon in several ways. For one thing, warmer water holds less oxygen, making it harder for fish to breathe. Because they're cold-blooded, they can't adjust their body temperature relative to the environment when conditions get too warm or too cold. Warmer temperatures speed up their metabolism, causing them to require more oxygen and food, and also forcing them to swim to find cooler waters, consuming more energy.

The heat makes it harder for them to swim and can stress salmon migrating to their spawning grounds, said Sue Grant, head of the state of salmon program at Fisheries and Oceans Canada. As a result, some don't survive to spawn, and those that do may produce less healthy offspring.
Are other impacts hurting salmon?

Yes. Besides extreme heat, climate change is causing drier conditions. Shrinking glaciers, smaller winter snowpacks and an earlier spring melt reduce the amount and depth of water in rivers, causing them to heat up more quickly, said Aaron Hill, executive director of the Watershed Watch Salmon Society.

"By the late summer, rivers are running low and becoming lethally hot for salmon," he said.

WATCH | Glacier melt in B.C. at shocking levels:




Glacier melt in B.C. at 'shocking' levels6 years ago
10:23Hot summer a 'sad window' into future without glaciers, reports Chris Brown 10:23

During droughts, humans also divert more water to cities and farmers, leaving less in the rivers — one of the big problems in California's Sacramento River, but also in water-stressed parts of B.C., such as the Interior and the east coast of Vancouver Island.

People are also taking too much groundwater that would otherwise cool streams as it seeps into them gradually, Hill said.

Deforestation from wildfires, pests such as mountain pine beetle and clearcut logging have increased erosion and landslides that can damage spawning grounds or block salmon migration to those spawning grounds.

"It's just this compounding, interacting set of impacts, both natural and human caused," Hill said.

But it's not just in rivers that salmon face challenges, as they spend much of their life at sea. There, they also face marine heat waves, such as the one dubbed "the blob," which raised temperatures along the Pacific coast by 3 to 5 C from 2013 until now, said Grant. That has altered the food web, replacing the large, fatty northern zooplankton that salmon normally eat with less nutritious zooplankton from the south.

"Animals that are feeding on these poor-quality animals at the base of the food web will grow more slowly," Grant said. "They'll be more vulnerable to predation."

WATCH | How a new 'blob' is set to impact marine life off B.C.'s coast:





A new “blob” is brewing, and it’s set to seriously impact marine life off B.C.’s coast2 years ago

7:10A new marine heat wave spreading across a portion of the Pacific Ocean off the coast of British Columbia has so far grown into one of the largest of its kind in the last four decades, officials say, second only to the infamous "blob" that disrupted marine life five years ago. 7:10

Atlantic salmon face similar impacts in the northwest Atlantic, where fish from all populations from both North America and Europe grow into adults.

"That's having a big impact on sea survival," Crabbe said, noting that fewer adults have been returning to Canada to spawn since the early 1990s.
Are all salmon vulnerable?

Some are more vulnerable than others. On the Pacific coast, chinook are doing particularly poorly, declining in numbers, size and reproductive rate throughout their range, from California to Alaska, said Grant, lead author of a 2019 report on how Pacific salmon are doing.

Pink and chum, species that spend less time in freshwater, where temperature changes are more extreme, were doing better than chinook, coho and sockeye. Grant said pink and chum did see some decline in 2019 and 2020, after the report was published.

Spawning sockeye salmon, a species of Pacific salmon, are seen making their way up the Adams River. Chinook, coho and sockeye, which spend more time in freshwater, are seeing bigger declines thank pink and chum, which spend more of their lives at sea. (Jonathan Hayward/The Canadian Press)

With Atlantic salmon, the young are particularly vulnerable, said Emily Corey, a PhD candidate at the University of New Brunswick, has been studying the effects of heat stress on juvenile Atlantic salmon.

She points to three main reasons why the young are more at risk:

They spend the first three to five years of their lives in freshwater, where temperatures can get more extreme.

They don't swim very well.

They tend to be territorial, so they don't like to move to a new location unless they have to.

That said, her research has found that some can move up to several kilometres to find cold water if necessary.
What is being done to reduce impact of extreme heat on salmon?

In June, the federal government announced the $647.1 million Pacific Salmon Strategy Initiative. It includes several kinds of solutions. Many are also targeted at Atlantic salmon under other programs:

Conservation and stewardship

This involves habitat monitoring and restoration, some of the goals of the Watershed Watch Salmon Society and the Atlantic Salmon Federation and its partners.

In Nova Scotia, the Margaree Salmon Association has installed water temperature monitors in the Margaree and Mabout rivers to help find hot spots. When they're found, work crews will do things such as plant trees to shade the river at those locations.

In New Brunswick, the Miramichi Salmon Association has been enhancing pools of cold water along the river by diverting the river's flow to carve them out and make them bigger.

The Donnelly Brook cold water enhancement project was completed by the Miramichi Salmon Association in 2014. It's designed to direct the flow of water to enlarge cold water pools within the waterway where salmon can shelter from extreme heat

. (Nathan Wilbur/Atlantic Salmon Federation)

On both coasts, conservationists say better land use planning and targeting salmon habitat for protection and reforestation will have a big impact. In New Brunswick, the ASF is working with the provincial government to protect the most-critical cold water springs and brooks feeding into important salmon rivers such as the Miramichi.

In B.C., Hill says there are huge swaths of great potential salmon habitat throughout the Fraser River watershed that have been blocked by structures such as culverts and road crossings. It's possible to replace those with alternatives that will allow salmon to use that habitat.

Meanwhile, in drier areas, Hill says better water planning is needed, along with licensing and regulating groundwater use, which hasn't yet been implemented by the provincial government.

Some B.C. restaurants remove wild salmon from menu in response to declining stocks
Drought danger grows as some parts of B.C. see no rain for almost 5 weeks

Changes, closures to fisheries and harvest

This is one happening on both coasts. In late June, the federal government closed 60 per cent of commercial salmon fisheries in B.C. and Yukon to conserve stocks. Most recreational fisheries for Fraser chinook have also faced widespread closures since 2019.

Many Atlantic salmon commercial fisheries have also closed. In 2018, the Atlantic Salmon Federation struck a 12-year deal with partners in Iceland and Greenland to ban commercial fishing on the west coast of Greenland and in the Faroe Islands. Already, more salmon seem to be returning to Canada, Crabbe said.

Atlantic salmon returned from the ocean in greater numbers last year

Biologists find glimmer of hope in year of higher Atlantic salmon numbers. 3:49

Important cold water pools in the Miramichi River system in N.B. are typically closed to recreational fishing when the water temperature exceeds 20 C, Crabbe added. In 2018, there were almost 60 days like that.

Stocking programs. Enhanced hatchery production is one of the solutions in the federal Pacific salmon strategy. In California, officials aim to save some Sacramento River chinook by trucking them to a hatchery. Hill said there are some desperate situations that call for that kind of response. But in general, it's controversial, as there's evidence hatchery-raised salmon are less fit to survive than their wild counterparts.

Thousands of salmon fry released in B.C. river to restore populations devastated by Big Bar landslide
Captive rearing can accidentally change animals so they may not survive in the wild
Could salmon go extinct due to climate change?

"No one's worried that they're all going to disappear," Grant said.

They do seem to be adapting to climate change to some extent. Both Atlantic and Pacific salmon are being found further north, and some northern populations are doing well. But some populations could disappear, especially in the south, and the loss will be felt by communities with deep and strong connections to salmon, both Crabbe and Grant say.

"They're really critical, critically important to the indigenous people of Western Canada for food, social, ceremonial reasons, and also really play a big role in fisheries," Grant said. "They're embedded in the culture … probably to all Canadians.

ABOUT THE AUTHOR

Emily Chung
Science and Technology Writer
Emily Chung covers science and the environment for CBC News. She has previously worked as a digital journalist for CBC Ottawa and as an occasional producer at CBC's Quirks & Quarks. She has a PhD in chemistry.

Interpretable machine learning predicts terrorism worldwide

CHINA CALLS SOUTH ASIA TERRORIST HOMELAND

by Zhejiang University

Credit: Zhejiang University

About 20 years ago, a series of coordinated terrorist attacks killed almost 3,000 people in the World Trade Center, New York and at the Pentagon. Since then, a vast amount of research has been carried out to better understand the mechanisms behind terrorism in the hope of preventing future potentially devastating acts of terror. Despite the large efforts invested to study terrorism, quantitative research has mainly developed and applied approaches aiming at describing regional cases of terrorist acts without providing reliable and accurate short-term predictions at local level required by policymakers to implement targeted interventions.   

Building a model to predict terrorism worldwide at fine spatiotemporal scales

Publishing in Science Advances, an international research team led by Dr. Andre Python from the Center of Data Science at Zhejiang University investigate machine learning algorithms capable of predicting and explaining at fine spatiotemporal scale the occurrence of terrorism perpetrated by non-state actors outside legitimate warfare (non-state terrorism) across the world. To cover all regions worldwide potentially affected by terrorism over a large time period, the authors consider about 21 million week cells, which are composed of 26,551 grid cells at 50 km × 50 km that cover inhabited areas in the world over a period of 795 weeks between 2002 and 2016. An interpretable tree-based machine learning algorithm is compared with alternative benchmark predictive models to predict and explain the probability of the occurrence of terrorism (response) in each week cell across the world. Informed by terrorism theory, the model includes 20 structural features—time-invariant variables that account for the effect of, e.g., per capita gross domestic product (GDP)—and 14 procedural features—dynamic variables that account for the fact that terrorism activity in the past affects the risk of terrorism in the future. To predict complex social phenomena such as terrorism at fine spatiotemporal scales, theoretically informed machine learning algorithms are likely to outperform parsimonious models using procedural features only, says Dr. Andre Python who led the research. The choice of the features included in the predictive model is crucial; the relevance of the model outputs and the predictive performance benefit from a solid conceptual understanding of the mechanisms driving terrorism at the scale on which predictions are made.

Can terrorism be accurately predicted?

While the predictive performance of machine learning algorithms is relatively high in areas that are highly affected by terrorism, it remains challenging to predict events that occur in regions that have not experienced terrorism over a long period. Algorithms may show a relatively good overall accuracy even at fine spatial and temporal resolution. However, it is virtually impossible to predict 'black swan events'—those events that occur only once over a very large period of time, says Python. Terrorist events occurred in less than 2% of the week cells considered in our global study. Data imbalance reduces the precision of the models, which is the number of week cells that encountered terrorism and have been correctly predicted divided by the total number of week cells predicted to encounter terrorism. This means that to prevent a large proportion of terrorist events in a region that is not much affected by terrorism, important resources are required to survey large areas where terrorism can potentially occur.

Along with disagreement among scholars about the definition of terrorism, the availability, spatiotemporal coverage, and the quality of publicly available data on terrorism and its potential drivers remain an important barrier to accurately predict terrorism globally and at policy-relevant scales, says Python. But terrorism data and socioeconomical drivers are becoming more detailed, comprehensive and more easily accessible. Also, the ongoing development in interpretable machine learning algorithms is very promising and will make these powerful tools more accessible to the research community and practitioners in the coming years.

The important role of interpreting the results of machine learning algorithms

Until recently, the interpretation of models was almost essentially reserved to classical statistical models which impose a parametric relationship between features and the response like in linear regression models where features are assumed to be linearly associated with the response, and the coefficient associated with each feature can be estimated and further interpreted in line with existing terrorism theories. In this study, the researchers used an interpretable machine-learning algorithm to obtain relatively high predictive performance without compromising the interpretability of the results.

The research team used a gradient-boosted trees algorithm, from which they compute the accumulated local effect (ALE) plots, which highlight the marginal difference in the predicted probability of terrorism occurrence with an incremental change in the feature. The relationship between features and the occurrence of terrorism is likely to be non-linear and cannot be identified by standard statistical models, said Python. The ALE plots are an important interpretative tool. They can capture these complex relationships learned by the algorithm, says Python. In our study, we assessed the relationship between 34 relevant features and the occurrence of terrorism in 13 regions worldwide, he adds. We observed that some feature relationships are stable while others are more variable across regions. These results allowed us to better understand regional similarities and differences in the effects of major drivers of terrorism.

The machine-learning algorithm has potentially captured complex relationships of local and global drivers of terrorism at a scale that is relevant for policy makers says Python. The interpretability of our model has important benefits beyond its predictive capabilities. Results can be analyzed in line with terrorism theories and can therefore contribute to build trust among modelers and practitioners, which is a crucial step to make these algorithms valuable for the entire research community.Researchers identify difficulties in balancing terrorism media coverage

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More information: Andre Python et al, Predicting non-state terrorism worldwide, Science Advances (2021). DOI: 10.1126/sciadv.abg4778

Journal information: Science Advances 

Provided by Zhejiang University

 

A comprehensive study of technological change

by Scott Murray, Massachusetts Institute of Technology

Distribution of predicted improvement rates (in percent per year) for all 1,757 technology domains. Domains to the right of dashed red line are improving faster than 36.5 percent per year, the predicted rate for integrated chips according to Moore's law. Credit: Institute for Data, Systems, and Society

The societal impacts of technological change can be seen in many domains, from messenger RNA vaccines and automation to drones and climate change. The pace of that technological change can affect its impact, and how quickly a technology improves in performance can be an indicator of its future importance. For decision-makers like investors, entrepreneurs, and policymakers, predicting which technologies are fast improving (and which are overhyped) can mean the difference between success and failure.

"The rate of improvement can only be empirically estimated when substantial performance measurements are made over long time periods," says Anuraag Singh SM '20, lead author of the paper. "In some large technological fields, including software and clinical medicine, such measures have rarely, if ever, been made."New research from MIT aims to assist in the prediction of technology performance improvement using U.S. patents as a dataset. The study describes 97 percent of the U.S. patent system as a set of 1,757 discrete technology domains, and quantitatively assesses each domain for its improvement potential.

A previous MIT study provided empirical measures for 30 technological domains, but the patent sets identified for those technologies cover less than 15 percent of the patents in the U.S. patent system. The major purpose of this new study is to provide predictions of the performance improvement rates for the thousands of domains not accessed by empirical measurement. To accomplish this, the researchers developed a method using a new probability-based algorithm, machine learning, natural language processing, and patent network analytics.

Overlap and centrality

A technology domain, as the researchers define it, consists of sets of artifacts fulfilling a specific function using a specific branch of scientific knowledge. To find the patents that best represent a domain, the team built on previous research conducted by co-author Chris Magee, a professor of the practice of engineering systems within the Institute for Data, Systems, and Society (IDSS). Magee and his colleagues found that by looking for patent overlap between the U.S. and international patent-classification systems, they could quickly identify patents that best represent a technology. The researchers ultimately created a correspondence of all patents within the U.S. patent system to a set of 1,757 technology domains.

To estimate performance improvement, Singh employed a method refined by co-authors Magee and Giorgio Triulzi, a researcher with the Sociotechnical Systems Research Center (SSRC) within IDSS and an assistant professor at Universidad de los Andes in Colombia. Their method is based on the average "centrality" of patents in the patent citation network. Centrality refers to multiple criteria for determining the ranking or importance of nodes within a network.

Those rates vary—from a low of 2 percent per year for the "Mechanical skin treatment—Hair removal and wrinkles" domain to a high of 216 percent per year for the "Dynamic information exchange and support systems integrating multiple channels" domain. The researchers found that most technologies improve slowly; more than 80 percent of technologies improve at less than 25 percent per year. Notably, the number of patents in a technological area was not a strong indicator of a higher improvement rate."Our method provides predictions of performance improvement rates for nearly all definable technologies for the first time," says Singh.

"Fast-improving domains are concentrated in a few technological areas," says Magee. "The domains that show improvement rates greater than the predicted rate for integrated chips—42 percent, from Moore's law—are predominantly based upon software and algorithms."

TechNext Inc.

The researchers built an online interactive system where domains corresponding to technology-related keywords can be found along with their improvement rates. Users can input a keyword describing a technology and the system returns a prediction of improvement for the technological domain, an automated measure of the quality of the match between the keyword and the domain, and patent sets so that the reader can judge the semantic quality of the match.

Moving forward, the researchers have founded a new MIT spinoff called TechNext Inc. to further refine this technology and use it to help leaders make better decisions, from budgets to investment priorities to technology policy. Like any inventors, Magee and his colleagues want to protect their intellectual property rights. To that end, they have applied for a patent for their novel system and its unique methodology.

"Technologies that improve faster win the market," says Singh. "Our search system enables technology managers, investors, policymakers, and entrepreneurs to quickly look up predictions of improvement rates for specific technologies."

Adds Magee, "Our goal is to bring greater accuracy, precision, and repeatability to the as-yet fuzzy art of technology forecasting.

New method uses patent data to estimate a technology's future rate of improvement

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More information: Anuraag Singh et al, Technological improvement rate predictions for all technologies: Use of patent data and an extended domain description, Research Policy (2021). DOI: 10.1016/j.respol.2021.104294

Provided by Massachusetts Institute of Technology 

Australia Tesla battery blaze under control after three days

This handout picture taken on July 30, 2021 and released on August 2 by Fire Rescue Victoria shows a fire from a 13-tonne lithium battery unit at a Tesla battery site in Australia.

A blaze at a massive Tesla battery site in Australia that started three days ago was brought under control on Monday, firefighters said.

Emergency services were first called to the Victoria Big Battery project—built by French renewable energy firm Neoen using Tesla batteries—on Friday morning.

A 13-tonne lithium battery inside a shipping container had caught fire at the site near Geelong, about an hour's drive from Australia's second city Melbourne, the Country Fire Service (CFA) said.

"There was one battery pack on fire to start with, but it did spread to a second pack that was very close to it," incident controller Ian Beswicke said in a statement.

Images released by the CFA showed a cloud of smoke rising from one of the units at the site.

The fire service said the incident had been declared "under control" just after 3 pm (0500 GMT) on Monday.

"Firefighters have successfully completed the operation of opening all doors to the container of the battery, with no sign of fire," the CFA said in an update.

Fire authorities said the cause of the blaze was unknown.

"A smaller number of firefighters and fire trucks from CFA will remain on scene for the next 24 hours as a precaution in case of reignition, the update added.

Fire authorities said the cause of the blaze was unknown.

The battery site—one of the largest in the world—is designed to store energy produced by renewables and send power to the grid.

Fire authorities said the cause of the blaze was unknown.

The battery site—one of the largest in the world—is designed to store energy produced by renewables and send power to the grid.

"The will continue taking thermal temperature readings two-hourly to monitor damaged units."

The battery site—one of the largest in the world—is designed to store energy produced by renewables and send power to the grid.

Local residents were initially warned about the possibility of toxic smoke but the Environmental Protection Agency said monitoring had shown "good air quality" near homes.

Neoen Australia managing director Louis de Sambucy said no one was injured in the incident, and with the site disconnected from the grid, there had been no impact on electricity supply.

"Investigation preparations are underway and physical inspections will commence once the CFA have completed their procedures," he said.

© 2021 AFP

HAIL HYDRA!

How headless hydra feel, react to prodding

by Rice University

Researchers at Rice University and the University of California, Davis, identified redundant neural networks in jellyfish-like, freshwater hydra by altering and then capturing them in microfluidic devices to be poked and prodded. The work is a step toward modeling how internal states and external stimuli shape the behavior of an organism with a highly dynamic neural architecture. Credit: Jeff Fitlow/Rice University

Even the simplest creatures seem extraordinarily complex when you look beneath the surface. Fortunately, hydra make that part easy.

Rice electrical and computer engineer Jacob Robinson and lead author and alumna Krishna Badhiwala of the university's Brown School of Engineering are taking advantage of the animal's transparency to do the hard part, manipulating the small, remarkably resilient creatures in just about every possible way to learn how they sense touch.

Their comprehensive analysis of hydra in the open-access journal eLife, in collaboration with biologist Celina Juliano and graduate student Abby Primack of the University of California, Davis, is a small step toward understanding neural networks in all living creatures.

Hydra vulgaris, freshwater cnidarians that look like miniature jellyfish polyps, expand and contract as they navigate their environments, but can also be prompted to do so by giving them a poke. The Rice lab has developed highly specialized equipment over the last decade to do that, temporarily constraining the animals in the channel of a microfluidic device to capture simultaneous images and data that detail their muscular and neural responses.

There, hydra can be physically prodded with a controlled amount of force to make them contract. For the new study, the researchers genetically modified hydra to express a green fluorescent protein when the associated neurons are activated, and then removed sets of those neurons—and even body parts—to see how networks respond upon poking the animals.

Their goal was to build a model of how internal states and external stimuli shape the behavior of an organism with a highly dynamic neural architecture.

"We need to establish the fundamentals for how animals like hydra work, in terms of their neurobiology, so we can then begin to make comparisons to really diverse animals," said Robinson, part of Rice's Neuroengineering Initiative. "I could see in five or 10 years there's going to be a lot of really interesting questions we can answer now that we've established some of the basics."

Neurons in hydra are concentrated in the oral region (adjacent to the tentacles) and the aboral region (around the "foot"), but the researchers identified two distinct kinds of neurons—"mechanically responsive" and previously discovered "contraction burst" neurons—distributed throughout the bodies. That helped explain the different firing patterns they discovered, depending on whether hydra contract spontaneously or are mechanically triggered.

Credit: Rice University

The researchers also found that both oral and aboral regions play a role in spontaneous contractions. The oral region, aka the hypostome, is more significant; because it appears to coordinate motor response, they learned that removing the hypostome entirely significantly reduced a hydra's response to prodding.

The aboral, aka peduncle, region appears to contain a high concentration of motor neurons involved in contraction, evidenced by calcium networks that activate from the foot on up when triggered either by the hypostome or by prodding "headless" hydra.

Most interesting was evidence that when hydra had one network or the other removed or were literally cut in half, the remaining neurons picked up the slack to maintain at least rudimentary function and/or regenerate the lost pieces.

Researchers at Rice University and the University of California, Davis, have identified redundant neural networks in jellyfish-like, freshwater hydra. Credit: Robinson Lab/Rice University

"When we started studying hydra, we wanted to understand as much as we could about how it works, its commonalities and differences when compared to other animals," Robinson said. "One of the things we didn't know about were the specific kinds of neural structures. Hydra in particular have a distributed nerve network, and we wanted to know whether particular regions of the animal process information in a centralized way, or if all the neurons are kind of the same."

It turned out the oral and aboral networks are fairly distinct in the way they control different aspects of hydra. "But it seems there's some redundancy and sensory information processing, which we also see in other animals," he said. "This idea of redundancy is really important for animal survival, so we see it pop up lots of times wherever we look."

While the radial nervous systems in hydra are fundamentally different from networks in bilateral creatures like mammals, there are similarities in the way all such systems share the workload when they must.

"I like to think about it this way: Let's look at all the crazy things nervous systems can do that have evolved from the same starting point," Robinson said. "That may allow us to identify fundamental principles that are harder to find in rodents and humans, where they might be obscured by other things that we've developed over time."

Robinson said neuroscientists who are looking beyond traditional small model organisms—rodents, worms, zebrafish and fruit flies—will be most interested in the hydra results. "There's a recognition that we really need to diversify our choices of the animals that we study," he said.

There are also implications for science initiatives beyond the animal kingdom. "That this particular type of nervous system can completely recover makes me think there are principals that relate to what makes a network stable," Robinson said. "These could be applied to stabilize power grids or the internet, inspired by nature.How environmental cues can affect behavior

More information: Krishna N Badhiwala et al, Multiple neuronal networks coordinate Hydra mechanosensory behavior, eLife (2021). DOI: 10.7554/eLife.64108

Journal information: eLife 

Provided by Rice University 

 

Punishment enforces cooperation in the fig-wasp mutualism: The exception proves the rule

by Smithsonian Tropical Research Institute

A cheater wasp (Eupristina sp.) laying eggs in a receptive fig of host Ficus microcarpa. Credit: Yan-Qiong Peng.

Removal of an offender's hand, tongue or ear: punishments described in Babylon's Hammurabi Code, depended on the nature of the crime. Published in 1771 B.C., the code set the first formal standards for business interactions. But scientists disagree about whether punishment is necessary to maintain mutually-beneficial interactions between animals and plants in nature. In a new study in Proceedings of the National Academy of Sciences, researchers at the Smithsonian Tropical Research Institute (STRI) in Panama and the Xishuangbanna Tropical Botanical Garden in China discovered the exception that clearly demonstrates that sanctions enforce cooperation in the fig-wasp mutualism.

The finely-tuned relationship between many different species of fig trees and their wasps took shape between 70 and 90 million years ago: a female wasp squeezes through a hole in the end of a fig losing her wings in the process. Once inside this sphere full of flowers, she places pollen and eggs on some of the flowers, and as she does, she may also deposit a drop of fluid that causes the developing flower to form gall tissue to feed wasp larvae. Wasps mate inside the fig, males chew exit holes and then females crawl out, carrying pollen as they fly off to repeat this drama in the next fig.

"The currency is unambiguous," said Allen Herre, staff scientist at the Smithsonian Tropical Research Institute in Panama. "One flower can either become one seed, which is good for the future of the tree species or one wasp, which is good for the future of the wasp species, and also is good for the tree—if the wasp carries its pollen to the next flower."

But what would happen if figs were not pollinated? No fig seeds would develop, and eventually, there would be no more figs trees. That would be a disaster for tropical forests where a huge number of animals, from birds, monkeys and bats in the treetops to wild pigs and even fish, depend on fig fruits to survive.

Botanists in China's Yunnan province discovered a fig species, Ficus microcarpa, is visited by two different, related wasp species. The first, Eupristina verticillata, is an active pollinator, has combs on its legs to harvest pollen, and pollen pockets. The second, another Eupristina species that has not yet been named, lacks combs and pockets. It lays its eggs in fig fruits and its larvae eat gall tissue, but it doesn't pollinate the fig.

"Once you have a mutualism established, because everybody benefits, you might not expect to lose it," Herre said. "We know of relatively few cases where this has clearly happened."

In previous studies of 16 fig species, fig trees appear to reward wasps that actually pollinate them and provide severe disincentives to wasps that do not. Trees drop figs containing large numbers of unpollinated flowers on the ground where they rot before the young wasps can develop and leave the fig. This punishment, or sanction, for non-pollinators should get rid of wasp species that don't pollinate.

"If only the wasps that actually pollinate figs preferentially survive, the mutualism between figs and wasps is maintained," said Charlotte Jander, who studied many different fig species in Panama. "In 16 studies of actively pollinated figs, Ficus microcarpa is the first that does not seem to eliminate non-pollinating wasps by aborting its own fruit."

"This is the first case ever reported in which a fig species seems to be ambivalent in the face of a non-helpful wasp," Herre said. "The ancestral pollinators in this case produced an 'evil twin' that stopped benefitting the fig by pollinating it. The fig-wasp mutualism is stable when you enforce good behavior. When you do not enforce good behavior, it seems that you may get burned."

Taking advantage of this special case, in Yunnan's Ficus microcarpa, researchers set up experiments in which they knew which wasp, a cheater or a pollinator, had entered a given fig. The non-pollinating wasps produced more female offspring than the pollinating wasps, perhaps because they did not waste time and energy pollinating. Figs containing only non-pollinating wasps formed more gall tissue.

The researchers call the non-pollinator a cheater, or a parasite, because it eats seeds but does not pollinate, as opposed to the mutualists that eat in return for pollinating. Because, in this case, the cheaters are better at reproducing than the pollinators, one would expect that they would replace the pollinators altogether, and the mutualistic relationship between figs and wasps would fall apart.

"We found that not only is there is a cheater, but, in every way, it does better than the pollinator," Herre said. "How can that happen?"

It turns out that the wind seems to play a role in maintaining the mutualism. Research conducted at STRI showed that pollinator wasps easily travel up to 30 kilometers or so. Researchers in China noticed a repeating seasonal pattern in the abundance of each species: During the non-monsoon season, non-pollinating wasps were more abundant, but during the monsoon seasons when the wind blows from the west, pollinators were more abundant.

"We are seeing a system that is not in equilibrium," Herre said. "In this species of host and these two wasp species, different proportions of incoming wasps from the two species result in different outcomes. But the take home is that sanctions prevent cheating and make for better, more mutually beneficial relationships."Is it sometimes OK to cheat? Wasps that do not pollinate figs may flourish when they go unpunished

More information: The evolution of parasitism from mutualism in wasps pollinating the fig, Ficus microcarpa, in Yunnan Province, China, Proceedings of the National Academy of Sciences (2021). www.pnas.org/cgi/doi/10.1073/pnas.2021148118

Journal information: Proceedings of the National Academy of Sciences 

Provided by Smithsonian Tropical Research Institute 

 

One insect species introduced decades ago to a small island had an effect on several insect populations

by University of Helsinki

The study system evolves on the Åland archipelago, which stands in the Baltic Sea, between the coasts of Finland and Sweden. (a) Samples used in the study originated from the five local communes of Finström (red), Föglö (green), Seglinge-Kumlinge (yellow), Saltvik (blue) and Sottunga (dashed-yellow). The habitat patches of this insect community have been studied since 1990 (Ojanen et al., 2013). (b) Melitaea cinxia caterpillars that were parasitized by Hyposoter horticola and the hyperparasitoid Mesochorus cf. stigmaticus were introduced to Sottunga (dashed yellow) from Finström (red) in 1991, and specimens of H. Horticola succesfully migrated to Seglinge-Kumlinge later in the 90’s. (c, d) The geographic distribution in Åland of the three species of this insect community changed after 1991. ‘X’:absent, ‘V’: present, and ‘??’: unknown. Credit: DOI: 10.1111/mec.16065

Larvae of the Glanville fritillary butterfly, Melitaea cinxia, were introduced to the island of Sottunga in the Åland Islands, Finland, in 1991. The original research project for which this introduction was aimed failed. However, although the island was previously free of the butterfly, the relocated species persisted, offering the ground for investigating how an entire insect community could be affected by one introduction event.

"What the researchers did not know 30 years ago was that the larvae carried along with them the butterfly parasitoid wasp Hyposoter horticola. The parasitoid then carried its hyperparasitoid wasp Mesochorus stigmaticus, and a mum-to-offspring transmitted bacterial symbiont Wolbachia pipientis that somehow increases the susceptibility of the host H. horticola to M. stigmaticus," says academy research fellow at the University of Helsinki, Dr. Anne Duplouy.

Thanks to yearly survey of the Åland butterfly population, researchers from the University of Helsinki and the Cornell University, U.S., have shown that the butterfly population introduced to Sottunga has faced several bottlenecks since 1991. It consequently is genetically quite diminished and faces a high risk of extinction.

"If local butterfly populations are small and unstable their parasitoids must be mobile enough to find hosts elsewhere. We have been able to show that the parasitoid H. horticola is dispersive in Åland. Furthermore, it has persisted and shows less genetic structure than the butterfly host. This probably explains their genetic mixing with populations on a nearby island after introduction to Sottunga. Introduced genotypes have potentially kept nearby populations from extinction during host population declines," Anne Duplouy says.

The hyperparasitoid M. stigmaticus isn't quite as mobile and has a smaller population size, so it suffers from inbreeding and is absent from some islands. Where the hyperparasitoid is absent, the parasitoid lineages with Wolbachia can flourish.

"The genetic signature of introduced wasp lineages gives us a window into what has happened in an island archipelago over the 25 years since their accidental introduction, including persistence through population bottlenecks, dispersal and interbreeding, as well as sorting among lineages depending on a hyperparasitoid and bacterial symbiont," says Dr. Saskya van Nouhuys from Cornell University, U.S., who has studied the parasitoid populations in Åland since 1998.

The researchers are excited to see how genetic methods can complement ecological studies and be useful in studying and making inferences about a population introduced decades ago.

"We have integrated population genetic and population ecology methods to find exciting insights about host and parasitoid ecology, as well as the influence of their bacterial symbionts over such short period of time," concludes University Researcher Dr. Abhilash Nair from the University of Helsinki.

Small things can have a major effect on the prevention of biodiversity loss

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More information: Anne Duplouy et al, Long‐term spatiotemporal genetic structure of an accidental parasitoid introduction, and local changes in prevalence of its associated Wolbachia symbiont, Molecular Ecology (2021). DOI: 10.1111/mec.16065

Journal information: Molecular Ecology 

Provided by University of Helsinki