Tag Archives: iron

Huge stash of abused Iron Age weapons discovered in a German hill fort

Researchers have just uncovered one of the largest stashes of Iron Age weapons ever discovered in Germany. Around 100 different artifacts have been recovered from the site.

Image credits LWL-Archäologie für Westfalen / Hermann Menne.

The advent of the Iron Age was an important stepping stone in our technological history. It was marked, quite unsurprisingly, by the introduction of iron as a material for tools and weapons. Iron-carbon alloys (what we refer to as ‘iron’) generally have similar properties to properly processed bronze (the metal it replaced), but iron has the huge advantages of being more abundant and simpler to produce, while having the downsides of requiring higher temperatures and more complex ore processing techniques.

At first, the use of it was quite limited, but as the know-how of smelting iron spread, so did its use. In Germany, the (early) Iron Age spanned between 800 to 45 BC, followed by the late Iron Age up until 1 BC, when the area became a Roman province. It was probably during the fighting for this transition that the stash was deposited at the site.

Stashed for a rainy day

The site is close to the German city of Schmallenberg, on the top of mount Wilzenberg. A press release by the Westfalen-Lippe Landscape Association, which made the discovery, explains that around 100 Celtic Iron Age artifacts were unearthed here.

This isn’t the first time the Wilzenberg site attracts academic interest. Work has been ongoing here ever since the 1950s. Prior digs have revealed a series of features suggesting that the site served as a hill fort back in the day, most notably ramparts. But there were some artifacts recovered over this time, as well.

Hillforts were relatively small fortifications made of local materials — from stone or wood to clay or soil — that were meant to discourage foreign incursions, or slow them down enough for a response to be mustered; hence, the ramparts. And, according to the findings, the Wilzenberg site also served as a weapon stash, most likely for locals or the soldiers manning the fort.

What prompted the discovery was the association’s use of metal detector devices to search for iron artifacts hidden beneath the structure’s former floor. Around 100 spears, swords, lance tips, belt hooks, and iron harness elements were discovered. Although dating them directly with sufficient accuracy proved impossible, the team explains that context cues would place the artifacts somewhere between the years 300 and 1 BC.

What was really peculiar about the finding is the condition the weapons here were uncovered in. Most of the swords here were severely damaged or deformed, being bent into halves or thirds, for example. Both the spears and lance tips were blunted. The team explains that the sheer scale of the damage seen here suggests this was an intentional, sustained effort. It was most likely carried out following a battle, as the victorious army wanted to prevent these weapons from being used again.

It’s also important to note that the weapons and artifacts were found piled up, not spread around, which indicates that they were carried to and deposited on the site. This suggests that the battle was fought elsewhere, and the weapons were then recovered, transported to Wilzenberg, damaged, and deposited here.

It’s very likely that the battle occurred around the city of Wilzenberg, and that the winners took these items as their trophy.

The original press release (in German) is available here.

A brewery in the Netherlands becomes the first iron-fueled factory in the world

A brewery in the Netherlands has become the first business in the world to use iron powder as fuel on an industrial scale.

Iron powder being burned in a combustion tube. Image credits Bart van Overbeeke / TU Eindhoven.

We tend to think of fire mostly as something that engulfs wood, coal, petrol, and other flammables. It’s practical to do so — those are the things we burn when we need something to burn. But from a chemical point of view, almost everything burns, given the right conditions — including iron.

The Swinkels Family Brewers in the Netherlands has become the first business to use iron as a fuel for industrial application. It worked together with the Metal Power Consortium and researchers at TU Eindhoven to install a cyclical iron fuel system (more on that shortly) at its Brewery Bavaria, which is able to heat up around 15 million glasses of beer a year.

Iron burn

“We are enormously proud to be the first company to test this new fuel on an industrial scale in order to help accelerate the energy transition,” said Peer Swinkels, CEO of Royal Swinkels Family Brewers. “As a family business, we invest in a sustainable and circular economy because we think in terms of generations, not years.”

“We combine this way of thinking with high-quality knowledge in the collaboration with the Metal Power Consortium. Through this innovative technology, we want to make our brewing process less dependent on fossil fuels. We will continue to invest in this innovation.”

Industries typically rely on fossil fuels for all their heat-intensive needs, since these hold a whole lot of energy in a very dense package. Finely-ground iron can serve the same purpose, however. In such a form and at high temperatures, iron burns easily.

Burning is the physical manifestation of a chemical reaction known as oxidation, and we perceive the energy given off by this reaction as light and heat. When iron is burned this way, there is no output of carbon dioxide (since there’s no carbon in iron). The only product is rust. The best part is that this rust, which is basically just iron oxide, can then be turned back into plain iron with the simple application of an electrical current.

In essence, if you use energy from solar, wind, or other clean sources, you can use iron filings as a sort of clean battery that charges with electricity and outputs heat — which is neat!

Other advantages of this system include how cheap and abundant iron is, how easy it is to transport (it doesn’t need to be cooled like hydrogen, for example), its high energy density, and the high temperatures it can output (up to 1,800 °C / 3,272 °F). It also doesn’t spoil and won’t lose its properties even if stored for a long time.

The cyclical iron system installed at Brewery Bavaria handles both the burning and recharging phases of the process. Depending on how energy is fed back into the used iron, it can store up to 80% of the energy input back into the iron fuel, which is comparable to the efficiencies of modern hydrogen-splitting techniques.

“While we’re proud of this huge milestone, we also look at the future,” says Chan Botter, who leads student team SOLID at TU Eindhoven, a group dedicated to the advancement of metal fuels.

“There’s already a follow-up project which aims to realize a 1-MW system in which we also work on the technical improvement of the system. We’re also making plans for a 10-MW system that should be ready in 2024. Our ambition is to convert the first coal-fired power plants into sustainable iron fuel plants by 2030.”

The system Botter talks about would have a theoretical efficiency of around 40%, which isn’t great, but it could prove to be a convenient and flexible way of storing energy, either for later use or for transport to another site. An advantage of this approach would be that our current energy-generation infrastructure can be adapted to use iron quite easily (as all that is changed is the type of fuel used).

It’s not yet clear if it would be economically-viable, but it’s definitely a very exciting idea — at least, I think it is. There’s also something very cool about the idea of burning iron for power.

Here’s a video detailing how the technology would work from TU Eindhoven:

The moon is getting rusty due to oxygen stripped from Earth’s atmosphere

With a virtually non-existent atmosphere and no liquid water, you’d think the moon would be the last place you’d find hematite — basically rusted iron that requires the presence of both iron and water. But that’s exactly what researchers have recently discovered at high latitudes on the moon.

Enhaned map of hematite on the moon’s nearside. Credit: Shuai Li.

The reddish dust we all know as rust is essentially a chemical product of the reaction between iron and oxygen. It’s very common on Earth (you can find iron oxides almost everywhere) but since there is no oxygen on the moon, you wouldn’t really expect any hematite. In fact, sample return missions during the Apollo era and subsequent satellite observations have only been able to find pristine metallic iron devoid of any sign of rust.

However, when planetary scientist Shuai Li of the University of Hawaii at Manoa was examining spectral data from NASA’s Moon Mineralogy Mapper (M3), as well as from the Chandrayaan-1 orbiter operated by the Indian Space Research Organization, he noticed signatures typical of hematite.

“When I examined the M3 data at the polar regions, I found some spectral features and patterns are different from those we see at the lower latitudes or the Apollo samples,” said Li in a statement. “I was curious whether it is possible that there are water-rock reactions on the Moon. After months of investigation, I figured out I was seeing the signature of hematite.”

Researchers had quite a mystery on their hands. Hematite requires both water and oxygen to form. For water, researchers had a hunch. Hematite was most abundant at the lunar poles, where there’s also ice water. But what about the oxygen — where could that come from?

Here too, geography might hold the answer. According to the data analyzed by Li and colleagues, most of the hematite on the lunar surface seems to be distributed on the lunar nearside, which always faces Earth. So the likely culprit was Earthly oxygen.

“This reminded me of a discovery by the Japanese Kaguya mission that oxygen from Earth’s upper atmosphere can be blown to the lunar surface by solar wind when the Moon is in Earth’s magnetotail. So, Earth’s atmospheric oxygen could be the major oxidant to produce haematite,” Li said.

Map of hematite on the moon. Red corresponds to more hematite. Credit: Shuai Li.

That’s not to say that hematite is absolutely absent from the far-side of the moon — it’s just that much fewer oxidative events were seen there, the researchers added.

“The tiny amount of water observed at lunar high latitudes may have been substantially involved in the haematite formation process on the lunar far-side, which has important implications for interpreting the observed haematite on some water poor S-type asteroids,” Li said.

Scientists may be able to learn more about how exactly oxidation occurs on the moon when NASA’s ARTEMIS mission return hematite samples from the polar regions. Beyond confirming the source of oxidation for lunar minerals, the sampled hematite could still retain oxygen isotopes from Earth’s ancient atmosphere. This way, scientists can learn more about our planet’s history.

“This discovery will reshape our knowledge about the Moon’s polar regions,” said Li. “Earth may have played an important role on the evolution of the Moon’s surface.”

The findings appeared in the journal Science Advances.

Supernova iron isotopes are raining down on Earth

Once a massive a star runs out of hydrogen fuel, it is ready to pull the curtains — and it does so with a bang! Supernovae are the most powerful explosions in the known universe, during which the dying star expels all sorts of heavy elements previously fused by nuclear reactions. Earth and the solar system at large are regularly showered by the products of supernovae.

Now, a recent study is highlighting tangible evidence pointing to such ongoing phenomena, describing rare isotopes of iron found in deep-sea sediments that are at least 33,000 years old.

The findings were described by researchers at the Australian National University (ANU) who analyzed sediments buried deep underwater in the Indian Ocean.

Kepler’s supernova. Credit: NASA/ESA/JHU/R.Sankrit & W.Blair.

“These clouds could be remnants of previous supernova explosions, a powerful and super bright explosion of a star,” Professor Anton Wallner, a nuclear physicist at ANU, said in a statement.  

In five sediment samples, the astronomers were able to identify iron-60, a rare isotope with a half-life of 2.6 million years. Since it should completely decay within 15 million years, it’s impossible that the isotope was incorporated during Earth’s formation billions of years ago. Without a doubt, its source is extraterrestrial and supernovae seem to be the likely culprits.

Previously, iron-60 was also found in Antarctic snow and in previously dated seabed deposits, ranging from 2.6 million to 6 millions years ago.

The presence of iron-60 in the newly described sediments suggests it was deposited at a rate of around 3.5 atoms per squar centimeter per year over the past 33,000 years. This slow rate of deposition suggests that the seeding supernova must have flooded interstellar space with its isotopic products.

Although the origin of the supernova cannot be determined, the researchers believe the explosion occurred millions of years ago, and its products must still be flowing through the Local Interstellar Cloud (LIC) — the interstellar cloud in the Milky Way through which the solar system is currently moving.

In the future, the astronomers would like to refine their timeline and come to an exact idea of when these isotopes made their way to Earth and confirm whether or not the LIC is the likeliest source.

“There are recent papers that suggest iron-60 trapped in dust particles might bounce around in the interstellar medium,” Professor Wallner said. 

“So the iron-60 could originate from even older supernovae explosions, and what we measure is some kind of echo. 

“More data is required to resolve these details.” 

The findings were reported in the Proceedings of the National Academy of Sciences.

Scientists find extreme exoplanet raining with iron

Rain is not necessarily synonymous with water on other planets. Astronomers working with the European Southern Observatory’s Very Large Telescope (VLT) have come across a bizarre exoplanet where it rains iron in the evening.

Artist illustration showing the night-side of WASP-76b, where it rains iron. Credit: ESO/M. Kornmesser.

The exoplanet, known as WASP-76b, is located about 6400 light-years away from Earth in the constellation Pisces. The ultra-hot gas giant orbits so close to its parent star that temperatures regularly climb above 2,400°C — but only on the planet’s day-side.

Just like the moon, WASP-76b is tidally locked, meaning it only shows one face to its parent star, since the planet takes just as long to rotate around its own axis as it does to orbit around the star. As a result, the night side is shrouded in perpetual darkness and is much cooler.

The exoplanet receives thousands of times more radiation than Earth does from the Sun, making the surface of Wasp-76b’s day side so hot it vaporizes metals like iron. Vigorous winds generated by the extreme temperature difference between the planet’s two sides carry a fraction of this iron vapor to the cooler side, where temperature decreases to 1,500°C. That’s still very hot, yet cool enough for iron vapor to condense and rain down.

“One could say that this planet gets rainy in the evening, except it rains iron,” says David Ehrenreich, a professor at the University of Geneva in Switzerland, who led the new research published in the journal Nature.

“Surprisingly, however, we do not see the iron vapor in the morning,” says Ehrenreich, adding that “it is raining iron on the night side of this extreme exoplanet.”

The discovery was made possible thanks to a new instrument equipped on ESO’s VLT in the Chilean Atacama Desert. Known as the Echelle SPectrograph for Rocky Exoplanets and Stable Spectroscopic Observations — or ESPRESSO — the instrument was originally designed to hunt for Earth-like planets around Sun-like stars. However, ESPRESSO has proven itself much more versatile than originally thought, allowing astronomers to detect a strong signature of iron vapor at the evening border that separates Wasp-76b’s two sides.

“We soon realised that the remarkable collecting power of the VLT and the extreme stability of ESPRESSO made it a prime machine to study exoplanet atmospheres,” says Pedro Figueira, ESPRESSO instrument scientist at ESO in Chile.

This crazy planet is not just some curious oddity. The insight gained by studying its atmosphere will help scientists better fine-tune and test climate and global circulation models. Ultimately, outlier planets like WASP-76 b will better our understanding of exoplanet atmospheres in general.

“What we have now is a whole new way to trace the climate of the most extreme exoplanets,” concludes Ehrenreich.

If you found an iron-raining planet weird, this exoplanet is actually not that peculiar. On Venus, it rains sulfuric acid, while on Neptune rainfall is in the form of diamonds.

In the Earth’s core, it’s snowing iron

Christmas is just around the corner, and with it, inevitably, come songs of “let it snow”. This particular carol is also relevant at the Earth’s core, a new study shows. According to the findings, iron snow blankets our planet’s internal core year-round.

Image credits Hendrik Kueck / Flickr.

Extreme pressure and heat don’t rule out snow, it seems, but it does make it more metal. Particles of iron that form in the Earth’s outer core ‘snow down’ on top of the inner core, a new study reports, and pile up in layers up to 200 miles thick.

The Earth’s inner core is hot, under immense pressure and snow-capped, according to new research that could help scientists better understand forces that affect the entire planet.

The snow is made of tiny particles of iron — much heavier than any snowflake on Earth’s surface — that fall from the molten outer core and pile on top of the inner core, creating piles up to 200 miles thick that cover the inner core. The findings could help explain anomalies seen in geophysical systems and improve our understanding of the processes taking place in the heart of our planet.

Inside knowledge

“The Earth’s metallic core works like a magma chamber that we know better of in the crust,” said Jung-Fu Lin, a professor in the Jackson School of Geosciences at The University of Texas at Austin and a co-author of the study.

Since the Earth’s interior is a tad inaccessible to us, researchers use seismic waves to investigate its structure and behavior. We know how seismic waves act in different contexts from experiments done on the surface, so we can estimate how they will behave inside the planet based on our current models of Earth’s structure. Whenever we see something that doesn’t go according to our predictions, it’s a good sign that our model was wrong — and we update it to fit the results.

One area where our predictions didn’t match results is at the boundary between the outer and inner core. Seismic waves move more slowly through this area than we expected, and move faster than we thought they would through the eastern hemisphere of the topmost inner core.

The study proposes that the layers of ‘iron snow’ that form on the core can explain the results. The existence of this slurry-like layer has been suggested since the early 1960s, but the data needed to support this view proved elusive.

In the study, Zhang and his team explain that crystallization was possible in this layer of the Earth and that about 15% of the lowermost outer core could be made up of iron-based crystals. It’s these crystals that fall down and settle onto the liquid inner core like a blanket of snow. This build-up is the cause of the anomalous seismic readings in the area, they add.

“It’s sort of a bizarre thing to think about,” said Nick Dygert, an assistant professor at the University of Tennessee who co-authored the study. “You have crystals within the outer core snowing down onto the inner core over a distance of several hundred kilometers.”

Seismic waves move faster through denser material — and the slurry-like coating of iron crystals slows them down. Because there is a variation in the thickness of these deposits around the inner core, with the eastern hemisphere showing thinner packs, seismic wave speed isn’t constant throughout the boundary.

“The inner-core boundary is not a simple and smooth surface, which may affect the thermal conduction and the convections of the core,” Zhang said.

The Earth’s core is the lynchpin in phenomena that affect the planet as a whole, from supplying the heat that drives plate tectonics to the generation of its magnetic field. Better understanding its structure and properties can help us make better sense of the processes it partakes in — and of other planets as well.

The paper “Fe Alloy Slurry and a Compacting Cumulate Pile Across Earth’s Inner‐Core Boundary” has been published in the Journal of Geophysical Research: Solid Earth.

The Wreck.

Novel nanocomposite material might prevent shipwrecks from rotting

Shipwrecks are coming — soon, to a museum near you. And it’s all thanks to nanotechnology.

The Wreck.

“The Wreck”, Knud-Andreassen Baade.
Image via Wikimedia.

A novel approach hopes to turn the damp, pitted wood of ancient shipwrecks into a showstopper. The team is currently using ‘smart’ nanocomposites to conserve the 16th-century British warship, the Mary Rose, and its artifacts. Should the process prove effective, museums will be able to display salvaged wrecks in all their glory without them rotting away.

The old that is strong does not wither

Thousands of shipwrecks have come to rest on ocean floors through the centuries. These drowned leviathans spark the passion of both researchers — who can learn a lot about past battles and ways of life from the wrecks — and public alike.

However, it’s very risky to go in and try to recover shipwrecks. Metal ships tend to weather the years underwater with some grace, but the wooden ones quickly rot away — after roughly a century, the only parts that remain are those that were buried in silt or sand soon after the sinking. Even worse, these timber skeletons quickly deteriorate once brought up to the surface.

While underwater, sulfur-reducing bacteria from the sea floor move into the wood and secrete hydrogen sulfide. This reacts with iron ions (rust) from items like nails or cannonballs, forming iron sulfide. This compound remains stable in environments that sport low levels of oxygen but binds with the gas to form acids that attack the wood.

In a paper being presented today at the 256th National Meeting & Exposition of the American Chemical Society (ACS), one team of researchers detail their efforts to keep wooden shipwrecks intact after recovery.

“This project began over a glass of wine with Eleanor Schofield, Ph.D., who is head of conservation at the Mary Rose Trust,” recalls Serena Corr, Ph.D., the project’s principal investigator.

“She was working on techniques to preserve the wood hull [of the Mary Rose] and assorted artifacts and needed a way to direct the treatment into the wood. We had been working with functional magnetic nanomaterials for applications in imaging, and we thought we might be able to apply this technology to the Mary Rose.”

Mary Rose.

Mary Rose in its specially-designed building at the Historic Dockyard in Portsmouth, United Kingdom.
Image via Wikimedia.

The Mary Rose was one of the first sailing ships built for war. Work on the wooden carrack (three-masted ship) began in 1510, and she was set to sea in July 1511. She remained one of the largest ships in the English navy for over three decades, during which she fought against the French, Scottish, and Brythonic navies — a task at which the Mary Rose excelled. The ship bristled with heavy cannons that popped out from gun-ports (which were cutting-edge technology at the time), and one of the first ships in the world capable of firing a full broadside.

Still, for reasons not yet clear, the ship sank in 1545 off the south coast of England. It was re-discovered in 1971 and recovered in 1982 by the Mary Rose Trust, along with over 19,000 artifacts and pieces of timber. The wreck helped provide a unique snapshot of seafaring and daily life in the Tudor period. It was displayed in a museum in Portsmouth, England, alongside the recovered artifacts.

Only 40% of the initial wooden structure survived the centuries underwater, and even this was rapidly degrading on the surface. So the Trust set out to preserve their invaluable wreck.

Corr’s goal was to avoid acid production by removing free iron ions from the wreck. She and her team at the University of Glasgow started by spraying the wood with cold water to keep it from drying out, which prevented further microbial activity, they explain. Afterward, they applied different types of polyethylene glycol (PEG) — a common polymer —  to the wreck. The PEG replaced water in the wood’s cells, forming a more robust outer layer.

The team, alongside researchers from the University of Warwick, are also working on a new family of magnetic nanoparticles to help in the conservation effort. They analyzed the sulfur species in the wood before the PEG treatment was applied, and then periodically as the ship dried.

This process will help the team design new targeted treatments to scrub sulfur compounds from the wood of the Mary Rose.

The next step, Schofield says, will be to use a nanocomposite material — based on magnetic iron oxide nanoparticles coated in active chemical agents — to remove these sulfur and iron ions. The nanoparticles will be applied directly to the wood and later guided through its pores to any particular areas using external magnetic fields. Such an approach should allow the team to completely remove the ions from the wood, they say.

“Conservators will have, for the first time, a state-of-the-art quantitative and restorative method for the safe and rapid treatment of wooden artifacts,” Corr says. “We plan to then transfer this technology to other materials recovered from the Mary Rose, such as textiles and leather.”

The paper “Magnetic nanocomposite materials for the archeological waterlogged wood conservation” has been presented today, Tuesday 21th August, at the 256th National Meeting & Exposition of the American Chemical Society (ACS).

RW Aur A.

We may have just witnessed a close-by star devour the remnants of a planet

A nearby star may have just consumed a planet, NASA reports.

RW Aur A.

Image credits Chandra X-ray Observatory / Harvard.

Some 450 light years away from Earth, the young star RW Aur A just finished chowing down on a planet — probably.

RW Aur A has captured astronomers’ attention ever since 1937. Nestled in the Taurus-Auriga Dark Clouds, which host stellar nurseries containing thousands of infant stars, its light tends to dim “every few decades for about a month,” according to NASA. Needless to say, this has made researchers very curious ever since we realized it. But then, back in 2011, something happened to throw all this interest into high gear: the star became dimmer far more often, and for longer periods of time.

A groundbreaking feast

To get to the bottom of things, a team of researchers pointed the Chandra X-ray Observatory towards RW Aur A over a five-year period. Chandra is a space telescope first launched in 1999, but which still boasts extremely sensitive X-ray sensors that can make sense of the radiation emitted even by young stars such as RW Aur A.

While young stars can be just as perky as any other, they’re typically shrouded in thick disks of gas, dust, and larger debris — which filter their radiation output and alter their intensity. While this makes less-sensitive instruments practically blind to the shrouded stars, instruments like Chandra can use the ‘filtered’ radiation to estimate what the disks are made of.

And that’s exactly what the team did in this case. According to the paper reporting the findings, Chandra detected surprisingly high levels of iron around RW Aur A. Since previous measurements didn’t record the same concentrations of iron (rather they picked up on much lower levels), the only possible explanation is that an event ejected a huge quantity of the element around the star.

They believe that all this iron came from a planet — or a few planetesimals — colliding with one another around the star. If any one of these bodies was rich in iron, it would explain the high levels seen in the disks around RW Aur A. Chandra recordings in 2017 revealed strong emission from iron atoms, indicating that the disk contained at least 10 times more iron than recordings captured in 2013 during a bright period.

The team speculates that this iron excess comes from a collision of two infant planetary bodies — including at least one object large enough to be a planet — in the space surrounding RW Aur A. Such an event would vaporize a large amount of material from the stars, including some iron. Furthermore, as the larger chunks of debris fall towards the star under its gravitational tug, they would release even more iron as the intense heat breaks them apart and solar winds batter them. Taken together, it would explain the high levels of iron observed in the star’s corona.

Better yet, it would also explain the dimming we see. As this debris falls into the star, it could be physically obscuring its light.

“If our interpretation of the data is correct, this would be the first time that we directly observe a young star devouring a planet or planets,” says Hans Guenther, who led the study out of MIT’s Kavli Institute for Astrophysics and Space Research.

With this in mind, an alternative explanation is also possible — if far less epic. RW Aur A is part of a binary star system, the sister of (you’ll never guess it) RW Aur B. If small grains of iron-rich particles can become trapped in certain parts of a star’s disk, and if that disk is perturbed by something massive (say, another star) the resulting interplay of tidal forces could stir the iron-rich particles — and make the disk seem richer in iron as all this dust falls into RW Aur A and obscures its light.

The team plans to continue their observations of the star over the next couple of years to see if iron levels stay constant. If they do, it would point to a massive source of iron (i.e. in favor of the collision scenario); if not, the tidal interaction between the two stars would seem like the more likely choice.

“Much effort currently goes into learning about exoplanets and how they form, so it is obviously very important to see how young planets could be destroyed in interactions with their host stars and other young planets, and what factors determine if they survive,” Guenther says.

Needless to say, I’m rooting for the collision scenario.

The paper “Optical Dimming of RW Aur Associated with an Iron-rich Corona and Exceptionally High Absorbing Column Density” has been published in the journal The Astronomical Journal.

Hydrogen sign.

Solar fuels just years away, propelled by breakthrough in catalyst research

New research from Caltech could bring an economically-viable solar fuel to the market in the next few years.

Hydrogen sign.

Image credits Zero Emission Resource Organisation / Flickr.

One of the holy grails of renewable energy researchers which they have been pursuing for decades, is the brewing of economically-viable solar fuel. It sounds like something you drill out of the core of a star, but in reality, it’s both much more useful and less dramatic than that: “solar fuels” are chemical compounds which can be used to store solar energy.

Most of the recent research performed in this field focused on splitting water into its constituent parts (hydrogen and oxygen) using only sunlight. It’s easy to see why — hydrogen produced this way would be a clean, cheap, easy-to-produce and generally widely-available fuel. It could be used to power solar cells, motor vehicles, or even spin the turbines of power plants. One of it’s most attractive qualities is that it would be virtually endless and produces zero emissions: the only reactionary product of a hydrogen engine (which burns the gas, i.e. combines it back with oxygen) would be plain old water.

We’re actually pretty close to having the solar fuels we so desire, the only thing we’re missing is the “cheap” part. Back in 2014, a team of Caltech researchers led by Professor Harry developed a water-splitting catalyst from layers of nickel and iron. It worked pretty well for a prototype, showing that it has potential and could be scaled-up. However, while the catalyst clearly worked, nobody knew exactly how it did so. The working theory was that the nickel layers were somehow responsible for the material’s water-splitting ability.

Catalyst model chemical structure.

Ball-and-stick model of the catalyst’s molecular structure. Iron atoms are blue, nickel is green, oxygen is shown in red and hydrogen in white.
Image credits Caltech.

To get to the bottom of things, a team led by Bryan Hunter from Caltech’s Resnick Institute created an experiment during which the catalyst was starved of water, and observed how it behaved.

“When you take away some of the water, the reaction slows down, and you are able to take a picture of what’s happening during the reaction,” Bryan says.

The experiment revealed that the spot where water gets broken down on the catalyst — called its “active site” — wasn’t nickel, but iron atoms. The results are “very different” from what researchers expected to find, Hunter says. However, that isn’t a bad thing. Our initial hypothesis was a dud, but now that we know exactly how the alloy works — meaning we won’t waste time researching the wrong avenues.

“Now we can start making changes to this material to improve it.”

Gray believes the discovery will be a “game changer” in the field of solar fuels, alerting people that iron is “particularly good” for this type of applications. As we now know what we should look for, we can go on to the next step — which is finding out how to make such processes unfold faster and more efficient, which translates to lower costs of the final fuel.

“I wouldn’t be at all shocked if people start using these catalysts in commercial applications in four or five years.”

The paper “Trapping an Iron(VI) Water Splitting Intermediate in Nonaqueous Media” has been published in the journal Joule.

Glenfield Park site.

UK archaeologists unearth “nationally important” collection of Iron Age artifacts

University of Leicester archaeologists have recovered a collection of rare Iron Age metal artifacts from a site in Glenfield Park, Leicestershire, England. Among the objects are decorated cauldrons, a complete sword, and a brooch from the 3rd century BC.

Glenfield Park site.

Aerial shot of the Glenfield Park roundhouse.
Image credits: University of Leicester Archaeological Services.

The collection includes eleven cauldrons, several fine-crafted ring-headed dress pins, an involuted brooch and a cast copper-alloy ‘horn-cap’, likely a part of a ceremonial staff, archaeologists say. The objects were inhumed at the site in a series of events that took part over a considerable span of time, they add, resulting in multiple episodes of sediment deposition across the settlement.

“Glenfield Park is an exceptional archaeological site, with a fantastic array of finds that highlight this as one of the more important discoveries of recent years,” said Dr. John Thomas, director of the excavation and project officer from the University of Leicester Archaeological Services.

Dr. Thomas explains that human occupation in the area during the middle Iron Age (5th to 4th centuries BC) was “modest”, consisting of a small settlement with no walls on the south-facing slopes of the spur. Some time later, around the 4th to 3rd centuries BC according to current radiocarbon dating results, the site underwent major changes. Individual roadhouses were enclosed, “there was far more evidence for material culture”, and the inhabitants adopted rituals and rites that seem to involve “deliberate burial of a striking assemblage of metalwork.”

That metalwork is what truly sets the site apart, Dr. Thomas says. Not only is it found in much larger quantities than in other known comparable sites in the area, the items are also of much higher quality and the composition of the artifacts is also unique.

[ALSO READ: Huge treasure of medieval silver and gold unearthed at abbey in France

“The cauldron assemblage in particular makes this a nationally important discovery,” Dr. Thomas said. “They represent the most northerly discovery of such objects on mainland Britain and the only find of this type of cauldron in the East Midlands.”

The team reports that the cauldrons appear to have been placed in a large circular enclosure ditch that surrounded a building. It’s not known why yet, but it’s very likely that this was a deliberate choice, not an accident, the archaeologists add. The cauldrons had been placed either upright or inverted, after which the ditch was filled in. One hypothesis is that this burial was meant to mark an end to the activities carried out at this part of the site. Other cauldrons were found buried across the site, suggesting that these rituals were used to mark significant events over a long period of time as the settlement developed.

They are fashioned from several distinct parts — iron for the rims, upper bands, and the ring handles attached to them, copper alloy for the body. Size-wise, they range between 14.2 and 22 inches (36-56 cm) in diameter, with the summed-up capacity of all cauldrons around 550 liters. This volume is quite significant, and the team suspects that they may have been used to provide food for large groups of people, for example at gatherings held in the site for the area’s wider Iron Age community.

CT scans performed on the cauldrons show evidence of wear, tear, and repair, pointing to long-term and repeated use of the objects. The amount of care and effort that went into repairing them further reinforces the hypothesis that the cauldrons were special for the Iron Age community at Glenfield Park.

“Due to their large capacity it is thought that Iron Age cauldrons were reserved for special occasions and would have been important social objects, forming the centerpiece of major feasts, perhaps in association with large gatherings and events,” Dr. Thomas said.

“They are rarely found in large numbers and, with the exception of a discovery in Chiseldon, where 17 cauldrons were found in a pit, there have been few excavated examples in recent years.”

Dr. Thomas adds that cauldrons held a symbolic value in the area at the time, as evidenced by their frequent appearance in early-medieval Irish and Welsh literature.

Green tea and iron don’t go well together

Rightfully touted for its many health benefits as an antioxidant, green tea doesn’t really play well with iron. A lab study on mice found that consuming an iron-rich diet can greatly reduce the tea’s benefits, as well as the iron’s.

Photo by Wild Bindy.

The main component in green tea is called epigallocatechin gallate (EGCG), a substance still under investigation for its potential to affect human health and disease. EGCG is used in many dietary supplements, but we still don’t know exactly how or why it works. Howeveer, we do know it potently inhibits myeloperoxidase, a pro-inflammatory enzyme released by white blood cells during inflammation. But when EGCG and iron are consumed together, they bind to each other, with EGCG losing its ability to inhibit myeloperoxidase.

“If you drink green tea after an iron-rich meal, the main compound in the tea will bind to the iron,” said Matam Vijay-Kumar, assistant professor of nutritional sciences, Penn State. “When that occurs, the green tea loses its potential as an antioxidant. In order to get the benefits of green tea, it may be best to not consume it with iron-rich foods.” Iron-rich foods include red meat and dark leafy greens, such as kale and spinach. According to Vijay-Kumar, the same results also apply to iron supplements.

The research can be especially useful for inflammatory bowel syndrome (IBD) patients. EGCG is especially helpful for this condition, as is iron. Dietary supplements containing both substances are often prescribed, which according to the study, is especially counterproductive as it cancels both their effects.

“It is important that IBD patients who take both iron supplements and green tea know how one nutrient affects the other,” Vijay-Kumar said. “The information from the study could be helpful for both people who enjoy green tea and drink it for its general benefits, as well as people who use it specifically to treat illnesses and conditions.”

“The benefit of green tea depends on the bioavailability of its active components,” said Beng San Yeoh, graduate student in immunology and infectious diseases and first author of the study. “It is not only a matter of what we eat, but also when we eat and what else we eat with it.”

It should be noted that the results haven’t been validated for humans.

Homes lay in ruins after two dams burst, flooding the small town of Bento Rodrigues in Minas Gerais state, Brazil. Photograph: Felipe Dana/AP

Cheap water filter is fantastically efficient: absorbs heavy toxic metals and can recover gold

Water pollution is a big issue, and so far there isn’t one single system capable of reliably filtering toxic heavy metals. These are either too small, or selectively filter certain metals when polluted water often contains a mix. Researchers at ETH Zurich claim they’ve hit a breakthrough. Using cheap, readily available materials they designed a filter that can retain over 99% concentration of mercury, gold cyanide or toxic potassium, to name a few. It can also absorb radioactive waste and help recycle gold.

Homes lay in ruins after two dams burst, flooding the small town of Bento Rodrigues in Minas Gerais state, Brazil. Photograph: Felipe Dana/AP

Homes lay in ruins after two dams burst, flooding the small town of Bento Rodrigues in Minas Gerais state, Brazil.
Photograph: Felipe Dana/AP

In November, ZME Science reported about one of the worst environmental disaster in history. Then, two dams at a Brazilian iron mine collapsed killing two dozen people, and spewing 60 million cubic meters of mining waste into the Rio Doce and, eventually, the Atlantic Ocean some days later. A quarter million people were deprived of clean, drinking water.

Events such as these serve as a stark warning: environmental disasters have far reaching consequences and should be prevented. When they do happen, however, we should also be prepared. It goes without saying that Brazil wasn’t equipped to handle such a situation, but few governments are.

The contaminated water (coloured water in vials) is drawn through the hybrid membrane by negative pressure; the heavy metal ions (red spheres) bind to the protein fibres in the process. The filtered water is of drinking quality. (Graphics: Bolisetty & Mezzenga, Nature Nanotechnology, 2016)

The contaminated water (coloured water in vials) is drawn through the hybrid membrane by negative pressure; the heavy metal ions (red spheres) bind to the protein fibres in the process. The filtered water is of drinking quality. (Graphics: Bolisetty & Mezzenga, Nature Nanotechnology, 2016)

Mitigating water contamination thus sounds like a priority, and the findings at ETH are most welcomed. Raffaele Mezzenga, Professor of Food and Soft Materials at ETH Zurich, and colleague Sreenath Bolisetty devised a hybrid membrane made out of activated charcoal and tough, rigid whey protein fibres. The whey proteins were first turned into amyloid fibrils, so these could stretch easily. Then both materials were applied on a cellulose filter substrate. The mix consists of 2% whey proteins and 98% activated charcol.

Together, the mix traps heavy metals in a non-specific way, including  lead, mercury, gold and palladium. Moreover, it  absorbs radioactive substances, such as uranium or phosphorus-32 — commonly found in nuclear waste, but also byproducts of cancer treatment. One popular mining technique involves treating mining ore with cyanide to extract precious metals. The ETH filter absorbs cyanide from contaminated water. Gold cyanide compounds are also used in the electronics industry to make conductive tracks on circuits. The industry can use this filter to recover and recycle the gold used in the circuit baths. “The profit generated by the recovered gold is more than 200 times the cost of the hybrid membrane,” says Mezzenga.

The setup is very simple: the hybrid membrane, a collection container and a vacuum pump. “A sufficiently strong vacuum could be produced with a simple hand pump,” says Mezzenga, “which would allow the system to be operated without electricity.”

Gold removed and recovered from polluted water. (Photograph: ETH Zurich/R. Mezzenga/S. Bolisetty)

Gold removed and recovered from polluted water. (Photograph: ETH Zurich/R. Mezzenga/S. Bolisetty)

Mezzenga says that the system is infinitely scalable. A filter the size of a truck should work just as well as one the size of a bottle cap.

Tests so far have been very promising. When mercury chloride was added, the concentration in the filtrate fell by 99.5%; 99.98% for potassium gold cyanide; 99.97% for lead salts; 99.4% for radioactive uranium.

“We achieved these high values in just a single pass,” emphasises Bolisetty, co-author of the invention. But even after multiple passes, the filter still proved useful.  The mercury concentration in the filtrate increased by a factor of 10 from 0.4 ppm (parts per millions) to 4.2 ppm after 10 passes. The filter can easily be replaced.  To filter half a litre of contaminated water, the researchers used a membrane weighing just a 10th of a gram, of which seven percent by weight was made up of protein fibres. “One kilo of whey protein would be enough to purify 90’000 litres of water, more than the amount of water needed in a human life time,” says the ETH professor.

The findings were presented in the journal Nature Nanotechnology.

Mercury iron might be the result of cosmic collision

The Earth contains a lot of iron, but it is not alone in the solar system in that aspect. Venus, Mars, the Moon and asteroids such as Vesta all have iron in their structure, but Mercury is the champion in that aspect: about 70 percent of its mass is iron! Now, researchers believe they have found why Mercury is so rich in this metal – the planet is the result of a cosmic ‘hit and run’.

The main proposed reason for the lunar iron is that the Moon was formed as a result of a giant impact with proto-Earth – but that can’t account for the much vaster Mercurian iron. Such a scenario requires that proto-Mercury was blasted apart with far greater specific energy than required for lunar formation, but in such a way that it retained substantial volatile elements and did not reaccrete its ejected mantle – in other words, something struck Mercury so hard that the planet lots half its mantle in a collision with proto-Earth or proto-Venus, leaving behind the iron-rich body we see today. The mantle which was torn from Mercury also didn’t re-accrete on to the planet.

Erik Asphaug from Arizona State University and Andreas Reufer of the University of Bern developed a statistical scenario for how planets merge and grow; apparently, Mars and Mercury lucked out, but in different ways.

“How did they luck out? Mars, by missing out on most of the action – not colliding into any larger body since its formation – and Mercury, by hitting the larger planets in a glancing blow each time, failing to accrete,” explains Asphaug.

Their model showed that this was unlikely, but not extremely unlikely.

“It’s like landing heads two or three times in a row – lucky, but not crazy lucky. In fact, about one in 10 lucky.”

The rather surprising result the model projected was that hit and run collisions are might not have been that uncommon in our solar system.

“The surprising result we have shown is that hit-and-run relics not only can exist in rare cases, but that survivors of repeated hit-and-run incidents can dominate the surviving population. That is, the average unaccreted body will have been subject to more than one hit-and-run collision,’ explains Asphaug. We propose one or two of these hit-and-run collisions can explain Mercury’s massive metallic core and very thin rocky mantle.”

Scientific Reference: Mercury and other iron-rich planetary bodies as relics of inefficient accretion.

Digital atlas shows oceans’ iron levels

Researchers have developed a three dimensional atlas which shows the concentrations of iron dissolved in the world’s oceans. This monumental achievement can be very valuable for scientists, but also for policy-makers.

Why is mapping iron in the oceans such a big deal ? Well for starters, iron plays a crucial role in the oceanic carbon cycle, as it is a key nutrient for phytoplankton. When phytoplankton bloom, they absorb carbon dioxide from ocean water, taking it to the depths of the ocean as they fall. The amount of iron they have available directly controls how much they can expand – but researchers are still struggling to understand the relative importance of different iron sources, such as atmospheric dust, continental erosion and upwelling of lava at sea-floor mid-ocean ridges. Basically, they want to understand if all iron sources are made equal, and if not (which seems more likely), what are the relative differences.

Now, a stunning 3D map finally shows iron concentrations in the water in detail. You can easily observe features such as plumes of iron extending for up to thousands of kilometres at the mid-Atlantic ridge as well as the coastal erosion patterns. The map doesn’t reveal one iron source dominating over the others, but rather it shows that all of them play an equally important role.

Modellers should now stop debating over what source is more important, and focus on more relevant issues, such as the ways in which iron moves through the system, says Robert Anderson, a chemical oceanographer at Columbia University’s Lamont–Doherty Earth Observatory in Palisades, New York.

“Some of these processes we’ve had hints of before, but we’ve never seen them so clearly,” he says.

The map was released today, 5 February at the 2014 Ocean Sciences Meeting in Honolulu, Hawaii, and is the first major achievement of GEOTRACES, an international programme launched four years ago to chart trace metals throughout the world’s oceans.

Source: Nature doi:10.1038/nature.2014.14774

Rubik’s Cube In Center Of Earth?

rubik cube earth core

When Swedish researchers published this theory of theirs, nobody took it seriously. Without paying much attention to the scientific community, they pursued and tried to prove what they were claiming. It seems now they have managed to present evidence which supports their way of viewing Earth’s internal core. The findings may be of significance for our understanding of the cooling down of the earth, and of the stability of the earth’s magnetic field.It’s been known for a whole lot of time that the inner core of the earth, a sphere consisting of a solid mass with a radius of about 1,200 km, is mainly made up of iron. But some seismic observations have revealed a some very strange things; for example, elastic waves pass more rapidly through this core in directions that are parallel to the earth’s axis of rotation than in directions parallel to the equator-a phenomenon that has not been previously explained. At the high temperatures which are at the center of our planet, they should be passing at the same speed regardless of their direction. So this brings us back to the scientists from the Uppsala University and KTH who have presented an explanation for this puzzling fact.

They published a series of articles in Science which had been previously published in Nature and Science. This comes after their innitial publishing in 2003 in which they wrote strong theoretical proof that the earth’s core assumes the “body” (as they called it), which is a structure that despite its high degree of symmetry evinces a surprisingly high level of elastic anisotropy. This body is a centered cubic crystal structure at high temperatures. This idea contradicts many other theories, but it has both experimental and theoretical support. To support it, they presented simulations of how seismic waves are reproduced in iron under similar conditions to the ones deep down. The result was a difference of about 12 percent depending on their direction, which could be a good enough explanation.

“We found that the body-centered cubic structure of iron is the only structure that could correspond to the experimental observations,” says Börje Johansson, professor of condensed-matter theory at Uppsala University.

The thermic balance is dependent on the amount of heat that is stored in Earth’s core. This heat is dependent on the crystal structure of the iron in the inner core. This structure forms a cube with atoms in each corner and a further atom in the middle of this cube. It’s orientation is such that allows its great diagonal to be directed along the earth’s axis of rotation, which makes it possible for the iron to evince sound propagations with the velocities observed.
“This study opens new perspectives for our understanding of the earth’s past, present, and future,” says Natalia Skorodumova, a researcher at the Department of Physics and Materials Science.
Truly a great study, but this theory is still in the works. A different, yet fascinating view.