Engineers at RMIT University have designed an innovative tubular structural system that can be packed flat for easier transport and pop up into strong building materials. This breakthrough is made possible by a self-locking system inspired by curved-crease origami—a technique that uses curved crease lines in paper folding.

Lead researchers Dr. Jeff (Ting-Uei) Lee and Distinguished Professor Mike (Yi Min) Xie, said that bamboo, which has internal structures providing natural reinforcement, inspired the tube design.

“This self-locking system is the result of an intelligent geometric design,” said Lee, from RMIT’s School of Engineering. “Our invention is suitable for large-scale use—a panel, weighing just 1.3 kg, made from multiple tubes can easily support a 75 kg person.”

Flat-pack tubes are already widely used in engineering and scientific applications, such as in biomedical devices, aerospace structures, robotics and civil construction, including pop-up buildings as part of disaster recovery efforts.

The new system makes these tubes quicker and easier to assemble, with the capability to automatically transform into a strong, self-locked state.

The research is published in Proceedings of the National Academy of Sciences. Other contributors to this work include Drs Hongjia Lu, Jiaming Ma and Ngoc San Ha from RMIT’s School of Engineering and Associate Professor Joseph Gattas from the University of Queensland.

“Our research not only opens up new possibilities for innovative and multifunctional structural designs, but it can also significantly improve existing deployable systems,” said Xie, from the School of Engineering.

“When NASA deploys solar arrays, for example, the booms used are tubes that were packed flat before being unfurled in space,” Lee said. “These tubes are hollow, though, so they could potentially deform under certain forces in space. With our new design, these booms could be a stronger structure.”

Xie explained that their smart algorithm enabled control over how the structure behaved under forces by changing the tube orientations.

“With our origami-inspired innovation, flat-pack tubes are not only easy to transport, but they also become strong enough to withstand external forces when in use,” Xie said. “The tube is also self-locking, meaning its strong shape is securely locked in place without the need for extra mechanisms or human intervention.”

Next steps

The team will continue to improve the design and explore new possibilities for its development.

“We aim to extend the self-locking feature to different tube shapes and test how the tubes perform under various forces, such as bending and twisting,” Lee said. “We are also exploring new materials and manufacturing methods to create smaller, more precise tubes.”

The team is developing tubes that can deploy themselves for a range of applications without needing much manual effort.

“We plan to improve our smart algorithm to make the tubes even more adaptable and efficient for different real-world situations,” Xie said.

Many sharks and rays are known to breach, leaping fully or partly out of the water. In a recent study, colleagues and I reviewed research on breaching and ranked the most commonly hypothesized functions for it.

We found that removal of external parasites was the most frequently proposed explanation, followed by predators chasing their prey; predators concentrating or stunning their prey; males chasing females during courtship; and animals fleeing predators, such as a ray escaping from a hammerhead shark in shallow water.

We found that the highest percentage of breaches, measured by the number of studies that described it, occurred in manta rays and devil rays, followed by basking sharks and then by eagle rays and cownose rays. However, many other species of sharks, as well as sawfishes and stingrays, also perform this behavior.

Why it matters

It takes a lot of energy for a shark or ray to leap out of the water—especially a massive creature like a basking shark, which can grow up to 40 feet (12 meters) and weigh up to 5 tons (4.5 tonnes). Since the animal could use that energy for feeding or mating, breaching must serve some useful purpose.

Sharks that have been observed breaching include fast-swimming predatory species such as blacktip sharks and blue sharks. White sharks have been seen breaching while capturing seals in waters off South Africa and around the Farallon Islands off central California.

However, basking sharks—enormous, slow-swimming sharks that feed by filtering tiny plankton from seawater—also breach. So do many ray species, such as manta rays, which also are primarily filter feeders. This suggests that breaching likely serves different functions among different types of sharks and rays.

The most commonly proposed explanation for breaching in planktivores, like basking sharks and most rays, is that it helps dislodge parasites attached to their bodies. Basking sharks are known to host parasites, including common remoras and sea lampreys. The presence of fresh wounds on basking sharks that match the shape and size of a lamprey’s mouth suggests that breaching has torn the lampreys off the sharks’ bodies.

Other species may breach to communicate. For example, white sharks propelling themselves out of the water near the Farallon Islands may do so to deter other sharks from feeding upon the carcass of a seal.

Researchers have seen large groups of mantas and devil rays jumping together among dense schools of plankton—presumably to concentrate or stun the plankton so the rays can more easily scoop them up. Scientists have also suggested that planktivorous sharks and rays may breach to clear the prey-filtering structures in their gills.

Understanding more clearly when and how different types of sharks and rays breach can provide insights into these animals’ life habits, and into their interactions with their own species and competitors.

How we did our work

I worked with marine scientists Tobey Curtis, Emmett Johnston, Alison Kock and Guy Stevens. Across our various projects, we have seen breaching in bull sharks in Florida, basking sharks in Ireland, white sharks in South Africa and central California, and manta rays in the Maldives. Each of us has proposed different explanations for why the animals did it.

We reviewed scientific studies and video footage to see what species had been observed to breach, under what conditions, and the functions that other researchers had proposed for them doing so. This included information gathered from data logging tags attached to sharks and rays, digital photography, and imagery from underwater and aerial drones.

Our review proposes further studies that could provide more information about breaching in different species. For example, attaching data loggers to individual animals would help scientists measure how quickly a shark or ray accelerates as it propels itself out of the water.

Experiments in aquarium tanks could provide more insight into why the animals breach. For example, scientists could add remoras to a tank containing bull sharks, which can live in an aquarium environment, and observe how the sharks respond when remoras attach themselves to the sharks’ bodies.

In the field, researchers could play audio recordings of splashes from breaches to elicit withdrawal or attraction responses from sharks tagged with ultrasonic transmitters. There remains much to learn about why these animals spend precious energy jumping out of the water.

This article is republished from The Conversation under a Creative Commons license. Read the original article.

In arid inland Australia lives one of Australia’s rarest birds: the night parrot. Missing for more than a century, a live population was rediscovered in 2013. But the species remains elusive.

Until recently, Australia’s known night parrot population numbered in the tens of birds, scattered across desert in Queensland and Western Australia.

But our research team—consisting of Indigenous rangers and scientists—has made a breakthrough discovery. We’ve detected the largest known night parrot population in the world: perhaps as many as 50, living in WA’s Great Sandy Desert, on land managed by the Ngururrpa people. Our results are published today.

Urgent action is needed to protect these vulnerable populations and ensure the night parrot doesn’t go missing a second time, perhaps for good.

A highly mysterious species

The night parrot was once found throughout Australia’s arid inland, but its numbers plummeted in the late 19th century.

The bird was not definitely recorded for more than 100 years, until a dead bird was found near Boulia in western Queensland in 1990. Another dead bird was found in Diamantina National Park, also in western Queensland, in 2006.

In 2013 a small population was found by naturalist John Young in south-western Queensland. That area is now a wildlife reserve.

Night parrots are notoriously difficult to detect. They build tunnels in dense spinifex and hide there by day, emerging at night to forage. They are known only from populations in remote south-west Queensland and central and northern Western Australia. The species is critically endangered.

In Western Australia, Indigenous cultural knowledge about the species includes stories about how difficult the bird is to find. There are also whispered stories of mothers telling children the night parrot’s call was the sound of an evil spirit, and warning them not to stray from camp.

What we did

The Ngururrpa Indigenous Protected Area is in the Great Sandy Desert. It comprises vast areas of sandplains and dunefields, and smaller areas of floodplain and spinifex which are key night parrot habitats.

Ngururrpa Rangers worked with scientists to learn how to use sound recorders to search for night parrots. We then searched for the birds on Country between 2018 and 2023.

We combined the rangers’ detailed knowledge of habitats, water and seed resources with geology maps, satellite imagery and fire history data. From this we selected 31 potential roosting areas, then deployed sound recorders called “songmeters” at those sites.

We wanted to detect the night parrots’ distinctive calls which consist of whistles, croaks and bell-like sounds.

The acoustic data we gathered was then analyzed to extract any bird calls in the night parrot’s frequency range. Potential detections were verified using a reference library of known night parrot calls.

Our results

We detected night parrot calls at 17 of 31 sites. Of these, ten were roost sites, where night parrot calls were detected in the hour after sunset and the hour before sunrise.

Individual night parrots are thought to have unique calls. We analyzed how many different calls we could hear, and how loud they were (which can tell us when birds are calling from different locations). From this we built a picture of the identity and number of individuals regularly occupying a site.

We extrapolated this across the 58 patches of potential night parrot habitat on the Ngururrpa Indigenous Protected Area. We concluded up to 20 roosting areas may be occupied by night parrots.

Based on the numbers at roosting sites where we recorded calls, we estimate 40–50 night parrots could be present in the Ngururrpa Indigenous Protected Area.

Fire and predators pose grave threats

Once we found the night parrot populations, we wanted to know what threats they faced.

We used camera-traps to identify predators and also collected their scats (poos) to analyze their diets.

Dingoes were the predator detected most frequently in night parrot roosting habitat. Our cameras captured them ten times more often than feral cats. And we found dingoes regularly eat feral cats at night parrot sites.

Based on information from other areas, we suspect cats are a key predator of night parrots. Dingoes could be important in suppressing cat numbers and helping the parrots survive. So, attempts to limit predators in night parrot habitat should not harm dingoes.

We also analyzed 40 years of satellite imagery to assess the threat of fire to night parrots’ roosting habitat. Based on the vegetation types and flammability of surrounding landscapes, we found bushfires sparked by lightning are a much bigger threat to night parrots in the Great Sandy Desert than in Queensland.

Strategic aerial and ground burning, to reduce fuel loads, already occurs in the Ngururrpa Indigenous Protected Area. As our knowledge of night parrots improves, these programs can become more targeted to protect key night parrot areas.

Keeping night parrots alive

A long-term monitoring program for night parrots on Ngururrpa Country should be established to help better understand and protect this vitally important population.

And the remote, wild nature of the landscape should be retained. This means minimizing disturbance from people and vehicles, and continuing to exclude livestock and weeds.

Ngururrpa Ranger Clifford Sunfly exlpains how rangers want to help protect night parrots into the future: “We would like to spend more time on Country to find where [night parrots] are and understand what they are doing. We want those scientists to come and help us catch some night parrots and tag them. We also need more snake-cams (inspection cameras) too and more songmeters. And a kit for collecting scats for DNA. One day we would love to have our own research facility for doing our night parrot surveys. It would be our dream to have our own research base on Ngururrpa.”

This article is republished from The Conversation under a Creative Commons license. Read the original article.