Hydrogen is gaining significant attention as an efficient way to store ‘green energy’ from renewables such as wind and solar. Compressed gas is the most common form of hydrogen storage, however it can also be stored in a liquid or solid state.

Dr Saidul Islam, from the University of Technology Sydney, said solid hydrogen storage, and in particular metal hydride, is attracting interest because it is safer, more compact, and lower cost than compressed gas or liquid, and it can reversibly absorb and release hydrogen.

“Metal hydride hydrogen storage technology is ideal for onsite hydrogen production from renewable electrolysis. It can store the hydrogen for extended periods and once needed, it can be converted as gas or a form of thermal or electric energy when converted through a fuel cell,” said Dr Islam.

“Applications include hydrogen compressors, rechargeable batteries, heat pumps and heat storage, isotope separation and hydrogen purification. It can also be used to store hydrogen in space, to be used in satellites and other ‘green’ space technology,” he said.

However, a problem with metal hydride for hydrogen energy storage has been its low thermal conductivity, which leads to slow charging and discharging times.

To address this the researchers developed a new method to improve solid-state hydrogen charging and discharging times. The study: Design optimization of a magnesium-based metal hydride hydrogen energy storage system, was recently published in the journal Scientific Reports.

First author Puchanee Larpruenrudee, a PhD candidate in the UTS School of Mechanical and Mechatronic Engineering, said faster heat removal from the solid fuel cell results in faster charging times.

“Several internal heat exchangers have been designed for use with metal hydride hydrogen storage. These include straight tubes, helical coil or spiral tubes, U-shape tubes, and fins. Using a helical coil significantly improves heat and mass transfer inside the storage.

“This is due to the secondary circulation and having more surface area for heat removal from the metal hydride powder to the cooling fluid. Our study further developed a helical coil to increase heat transfer performance.”

The researchers developed a semi-cylindrical coil as an internal heat exchanger, which significantly improved heat transfer performance. The hydrogen charging time was reduced by 59% when using the new semi-cylindrical coil compared to a traditional helical coil heat exchanger.

They are now working on the numerical simulation of the hydrogen desorption process, and continuing to improve absorption times. The semi-cylindrical coil heat exchanger will be further developed for this purpose.

Finally, the researchers aim to develop a new design for hydrogen energy storage, which will combine other types of heat exchangers. They hope to also work with industry partners to investigate real tank performance based on the new heat exchanger.

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Materials provided by University of Technology Sydney. Note: Content may be edited for style and length.

The research, published in Cell Reports by Assistant Professor Kshitiz in collaboration with Dr. Junaid Afzal in the cardiology department at the University of California San Francisco, presents a method that accelerates maturation of human cardiac cells towards a state suitable enough to be a surrogate for preclinical drug testing.

“There is a very strong need to create human cardiac constructs for all sorts of applications. Small animal models just do not recapitulate human heart biology, and human samples are scarce,” says Kshitiz. “This matters because all drugs need to be tested for their toxicity to heart. It is widely believed that a large number of them unnecessarily fail clinical trials because we do not have human samples to test them with.”

Kshitiz and Afzal first identified the need to create a matured human cardiac tissue during their time together at Johns Hopkins Medicine.

“When methods were developed to differentiate human pluripotent stem cells to cardiac cells, it created a big hope that finally we will have human heart constructs to work with,” said Afzal. “While it is straightforward to get human cardiac cells, they are similar to fetal cells. What we need is adult cells.”

Cardiovascular safety is the number one cause for failure of preclinical drug development, and there is a long standing need to create human cardiac tissue models to test drugs for cardiotoxicity. Currently, the small animal heart models display vastly different biochemical, physiological, and genetic features from humans — making it difficult to replicate the human heart in preclinical studies. In particular, it is very difficult to perform metabolic assessment of current cardiac constructs. Heart beats continuously and is a highly metabolically active organ.

“Metabolic and redox maturation is critical for heart cells, and we are able to achieve it and possibly create a gold standard — fundamentally shifting our expectations of creating a metabolically mature cardiac tissue,” the researchers said.

In the study, the researchers utilized the cardiac biology in an adult human heart to rapidly mature differentiated cardiac cells into a more adult-like state. Within 30 days, the researchers achieved cardiac cells that displayed structural, mechanical, metabolic, and electrophysiological characteristics close to adult heart muscle.

The researchers are optimistic that this application will not only be used for preclinical drug testing, but can also be used in future precision disease modeling to study disease mechanisms and test for regenerative therapies. The researchers hope that the many drugs that fail unnecessarily due to non-human methods will be salvaged for cures for cancer, immune and neurological diseases.

UConn Health researchers Yamin Liu, Wenquang Du, Yasir Suhail, Pengyu Zong, Jianlin Feng, Visar Ajeti, Maya Yankova, Alix Deymier, and Lixia Yue also contributed to this study.

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Materials provided by University of Connecticut. Original written by Courtney Chandler. Note: Content may be edited for style and length.

Astronomers using Hubble and other telescopes have deduced that the star blew off a huge piece of its visible surface in 2019.

This has never before been seen on a star. Our petulant Sun routinely goes through mass ejections of its outer atmosphere, the corona. But those events are orders of magnitude weaker than what was seen on Betelgeuse. The first clue came when the star mysteriously darkened in late 2019. An immense cloud of obscuring dust formed from the ejected surface as it cooled. Astronomers have now pieced together a scenario for the upheaval. And the star is still slowly recovering; the photosphere is rebuilding itself. And the interior is reverberating like a bell that has been hit with a sledgehammer, disrupting the star’s normal cycle. This doesn’t mean the monster star is going to explode any time soon, but the late-life convulsions may continue to amaze astronomers.

Analyzing data from NASA’s Hubble Space Telescope and several other observatories, astronomers have concluded that the bright red supergiant star Betelgeuse quite literally blew its top in 2019, losing a substantial part of its visible surface and producing a gigantic Surface Mass Ejection (SME). This is something never before seen in a normal star’s behavior.

Our Sun routinely blows off parts of its tenuous outer atmosphere, the corona, in an event known as a Coronal Mass Ejection (CME). But the Betelgeuse SME blasted off 400 billion times as much mass as a typical CME!

The monster star is still slowly recovering from this catastrophic upheaval. “Betelgeuse continues doing some very unusual things right now; the interior is sort of bouncing,” said Andrea Dupree of the Center for Astrophysics | Harvard & Smithsonian in Cambridge, Massachusetts.

These new observations yield clues as to how red stars lose mass late in their lives as their nuclear fusion furnaces burn out, before exploding as supernovae. The amount of mass loss significantly affects their fate. However, Betelgeuse’s surprisingly petulant behavior is not evidence the star is about to blow up anytime soon. So the mass loss event is not necessarily the signal of an imminent explosion.

Dupree is now pulling together all the puzzle pieces of the star’s petulant behavior before, after, and during the eruption into a coherent story of a never-before-seen titanic convulsion in an aging star.

This includes new spectroscopic and imaging data from the STELLA robotic observatory, the Fred L. Whipple Observatory’s Tillinghast Reflector Echelle Spectrograph (TRES), NASA’s Solar Terrestrial Relations Observatory spacecraft (STEREO-A), NASA’s Hubble Space Telescope, and the American Association of Variable Star Observers (AAVSO). Dupree emphasizes that the Hubble data was pivotal to helping sort out the mystery.

“We’ve never before seen a huge mass ejection of the surface of a star. We are left with something going on that we don’t completely understand. It’s a totally new phenomenon that we can observe directly and resolve surface details with Hubble. We’re watching stellar evolution in real time.”

The titanic outburst in 2019 was possibly caused by a convective plume, more than a million miles across, bubbling up from deep inside the star. It produced shocks and pulsations that blasted off the chunk of the photosphere leaving the star with a large cool surface area under the dust cloud that was produced by the cooling piece of photosphere. Betelgeuse is now struggling to recover from this injury.

Weighing roughly several times as much as our Moon, the fractured piece of photosphere sped off into space and cooled to form a dust cloud that blocked light from the star as seen by Earth observers. The dimming, which began in late 2019 and lasted for a few months, was easily noticeable even by backyard observers watching the star change brightness. One of the brightest stars in the sky, Betelgeuse is easily found in the right shoulder of the constellation Orion.

Even more fantastic, the supergiant’s 400-day pulsation rate is now gone, perhaps at least temporarily. For almost 200 years astronomers have measured this rhythm as evident in changes in Betelgeuse’s brightness variations and surface motions. Its disruption attests to the ferocity of the blowout.

The star’s interior convection cells, which drive the regular pulsation may be sloshing around like an imbalanced washing machine tub, Dupree suggests. TRES and Hubble spectra imply that the outer layers may be back to normal, but the surface is still bouncing like a plate of gelatin dessert as the photosphere rebuilds itself.

Though our Sun has coronal mass ejections that blow off small pieces of the outer atmosphere, astronomers have never witnessed such a large amount of a star’s visible surface get blasted into space. Therefore, surface mass ejections and coronal mass ejections may be different events.

Betelgeuse is now so huge now that if it replaced the Sun at the center of our solar system, its outer surface would extend past the orbit of Jupiter. Dupree used Hubble to resolve hot spots on the star’s surface in 1996. This was the first direct image of a star other than the Sun.

NASA’s Webb Space Telescope may be able to detect the ejected material in infrared light as it continues moving away from the star.

With trillions of individuals migrating every year, insects are some of the most common migrating animals on Earth. They include species of renown, such as the monarch butterfly, as well as species of enormous societal and environmental importance, such as locusts, mosquitos, and bees. But even though insect migrants far outnumber better-known migrants, such as birds or mammals, their migration is the least understood form of long-range animal movement.

The problem, for the most part, has been methodological. “Studying insects on the move is a formidable challenge,” says first author Myles Menz, who conducted the research at MPI-AB and is now a lecturer at James Cook University in Australia. “They’re usually too numerous to mark and find again, and too small to carry tracking devices.”

Much of what we know about insect migration has come from studies that sample insects at a single moment in time, such as through radar or direct observation, which has left vast blank spots in our knowledge. “Understanding what insects do during migration, and how they respond to weather, is a last frontier in migration science,” says Menz.

The current study, which followed radio-tagged individuals in a light aircraft, is the first to continuously study nocturnal migrating insects in the wild and represents the longest distance over which any insect has been continuously tracked in the field. The team, which includes researchers from the MPI-AB and University of Konstanz in Germany and the University of Exeter in the UK, focused on the death’s-head hawkmoth—a large, nocturnal migrant that travels up to 4000 kilometers between Europe and Africa every year. Like many insects, the species is a multi-generational migrant, which means that no individual knows the entire route.

At the MPI-AB in Konstanz, Germany, the team reared caterpillars until adulthood in the laboratory to ensure that individuals were naïve. When moths emerged as adults, they were fixed with radio tags weighing 0.2 grams—less than 15% of adults’ body weight. “The moths would probably eat more weight than that in a night, so these tags are extremely light for the insects,” says Menz.

The researchers released the tagged moths and waited for flight to begin, after which they chose a single individual to follow at a time. The team followed 14 moths each for up to 80 kilometers or 4 hours—a stretch long enough to be considered migratory flight—using antennas mounted on a Cessna airplane to detect precise locations every five to 15 minutes. Insects were followed in the south-south-west direction from Konstanz into the Alps, which follows the route taken by hawkmoths towards the Mediterranean and Northwest Africa.

Due to practical constraints of flying in an aircraft, the scientists tracked moths continuously until the insects stopped on route. “When you’re in an airplane, it becomes extremely difficult to wait for the insects to begin migrating again because you would have to be in the air when this happens, which could be anytime in the night,” says senior author Martin Wikelski, a movement ecologist from the MPI-AB and University of Konstanz, who piloted the plane during the study.

The results show that moths maintained perfectly straight trajectories for long distances during flight. This was not because they waited for favorable tailwinds. Rather, they employed a range of flight strategies to buffer against prevailing winds, allowing them to hold their course throughout the night. When winds were favorable, they flew high and slow, allowing the air to carry them. But during harsh headwinds or cross winds, they flew low to the ground and increased speed to keep control of their path.

Says Menz: “For years it was assumed that insect migration was mostly about getting blown around. But we show that insects are capable of being great navigators, on par with birds, and are far less vulnerable to wind conditions than we thought.”

“By showing that it is technically possible to continuously monitor individual insects over migration, and to observe their flight behavior in detail, we hope to inspire more studies to answer many more big questions in this area.”

For the study authors, the next step is to answer the question of how moths are able to maintain such straight lines. “Based on past lab work, it’s possible that the insects are using internal compasses, both visual and magnetic, to chart their way around the world,” says Menz.