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The Frontiers of Knowledge Award goes to Anne L’Huillier, Paul Corkum and Ferenc Krausz for enabling subatomic particles to be observed in motion over the shortest time scale captured by science




image: Anne L’Huillier, winner of the Frontiers of Knowledge Award in Basic Sciences.
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Credit: BBVA Foundation

The BBVA Foundation Frontiers of Knowledge Award in Basic Sciences goes in this fifteenth edition to Anne L’Huillier (Lund University, Sweden), Paul Corkum (University of Ottawa, Canada) and Ferenc Krausz (Max Planck Institute of Quantum Optics, Germany), the three pioneers of “attosecond physics” or “attophysics” whose work has made it possible to observe subatomic processes unfolding over the shortest time scale captured by science.

The awardees, says the committee, “have shown how to observe and control the motion of electrons in atoms, molecules, and solids with ultrashort light pulses on time scales of about one hundred attoseconds. One attosecond is approximately the time for light to travel across an atom and is the natural scale for electronic motion in matter. This time scale was previously inaccessible to experimental studies due to the lack of light pulses with short enough duration.”

Thanks to attophysics, scientists can now directly observe natural processes that were once off-limits to the human eye. “It is a huge step to know that what we can imagine theoretically can now be tested experimentally. This interplay between experiment and theory is inspiring a lot of ideas,” remarked committee chairman Theodor W. Hänsch, Director of the Laser Spectroscopy Division at the Max Planck Institute of Quantum Optics (Germany) and winner of the Nobel Prize in Physics.

Attophysics, says laureate Paul Corkum, “is about making the fastest measurements that we as humans can make. And that, I think, is what places it at the forefront of knowledge.” An attosecond, he explains, “is incredibly short. So an attosecond is to a second as a second is to the age of the universe. Can you imagine something as short as that?” In figures, an attosecond is one billionth of a billionth of a second, that is, 0.000000000000000001 seconds.


“That’s the time scale for the movement of electrons across all the atoms matter is composed of, including our own bodies,” adds Fernando Martín, Professor of Physical Chemistry at the Universidad Autónoma de Madrid, Scientific Director of IMDEA Nanociencia and one of the nominators of the three awardees. “So to achieve real-time imaging of electron motion in matter, we needed a technology that would give us access to that time scale. And that is precisely what these researchers have achieved.”

An ultrafast “camera” to “film” electrons in motion

The tools developed by L’Huillier, Corkum, and Krausz act like a camera with a shutter time so dizzyingly ultrafast that it can capture the movement of a hydrogen atom electron that takes 150 attoseconds to circle the nucleus.

Prof. Martín elaborates on this example: “If you want to film how a car moves, you have to take snapshots at very close intervals, so the movement registers.”

“If you take photos with an exposure time of one minute, say, by the time you press the shutter the car has gone and all you have is a blurred image at best. In other words, to visualize an object, you need to take snapshots at intervals and with a duration far shorter than the time that object takes to move significantly. This is what the three laureates have done on the time scale of electron motion, thanks to light pulses generated with ultrafast lasers that emit for just a few attoseconds.”

Attophysics techniques not only mean that we can now capture the movement of electrons, they have also conjured the possibility of manipulating these subatomic particles. “Once you have gained the ability to visualize this movement in real time,” says Martín, “you can likely use the same light sources to manipulate it, eventually modifying its behavior and properties, with applications in multiple domains from biomedicine and electronics to the search for new clean energy sources.”

The committee’s citation ends with a similar reflection: “These groundbreaking contributions have opened exciting new frontiers in different areas, including atomic physics, photochemistry, and materials science.”

The findings that sowed the seeds of attophysics

In 1987, Anne L’Huillier made a discovery that laid the groundwork of the attophysics field. When working as a postdoctoral researcher at the Saclay Nuclear Research Centre near Paris, she became intrigued by the question of what would happen if atoms were subjected to short, intense laser pulses of infrared light. She expected to see fluorescent light, but was surprised to find that the atoms appeared to be emitting light waves at very high frequencies, that is, extremely high-energy X-rays.

L’Huillier had achieved the highest frequency ever recorded through the interaction of laser light pulses with matter. “It was truly fascinating; the first step toward generating an attosecond pulse. And I have never stopped working in the field, contributing to different aspects of the body of research.”

Retracing her steps, the scientist realized that the laser was acting on the atoms the way waves act on seaweed on a rock. Each time a wave comes in, the seaweed unfurls to its full extent, only to retract when the wave recedes. The seaweed, in other words, moves up and down in time with the waves. In similar fashion, the arrival of a laser pulse pulls away the electrons surrounding the atom, which then resume their initial position when the pulse stops. It was on the way back, it turned out, that the electrons emitted those high-frequency light waves.

The seaweed metaphor was originally devised by Paul Corkum on the basis of L’Huillier’s reconstruction. As well as coming up with an intuitive visualization of the phenomenon, he decided to study it from a theoretical standpoint, developing a model that mathematically described the interaction between laser and atoms. It was L’Huillier’s discovery and Corkum’s theoretical model that sowed the seeds of today’s attophysics.

The shortest light pulses in the history of science

While visiting Vienna in the 1990s, Corkum met Ferenc Krausz, then studying there as a young postdoc. “Corkum inspired me with his concepts like no one else,” Krausz recalls today. “What I took from them was that there might be a way to move forward into a time domain that was completely inaccessible beforehand, and render extremely fast processes observable.”

Corkum and Krausz were familiar with L’Huillier’s work and quickly agreed that it could hold the key to generating the shortest light flashes ever. They were aware that, in general, short light pulses were the vehicle to access and observe the universe of the small. Indeed with pulses just a little longer than those they were aiming for, scientists had already managed to glimpse the movement of atoms within molecules.

“The idea is the same as when you capture the motion of a Formula 1 car or a bullet. You take a series of snapshots and then reconstruct how the bullet actually hits the wall,” Krausz explains. These snapshots can then be reproduced in slow motion to see the movement in all its detail.

But they wanted to take this idea of ultrafast photography even further, and apply it to tracing the movement of electrons. These minuscule particles move up to a thousand times faster than atoms, so would require much shorter light pulses than were possible at the time. What was needed was to descend to the attosecond scale.

The light waves generated by L’Huillier seemed the ideal candidate for the task, as they oscillated at such high frequencies that they emitted light pulses of a few attoseconds duration.

The challenge didn’t end there, however. The pulses were short, certainly, but they followed each other in quick succession. And for them to perform in the style of an ultrafast camera, they would have to be isolated into individual light flashes and emitted one by one.

Krausz describes it thus: “Having a whole train of pulses is still something like having a camera that has a very high shutter speed. But it doesn’t open the shutter just once, it opens and closes the shutter all the time, which is, in many cases, not very helpful. You want to be able to open the shutter once and close it very quickly, to take just one snapshot. This is also true when we try to actually capture microscopic processes.”

The solution they came up with was simple but effective. They decided to go as far as possible in shortening the initial infrared pulse (the wave hitting the rock), so the electron (the seaweed) would rise and fall just once, and by doing so obtained a single light pulse lasting around one hundred attoseconds.

This experiment, published in 2001, marked what Krausz describes as “the birthday of experimental attophysics.” As well as opening the door to detailed observation of electron motion, it was able to corroborate a series of predictions formulated decades back by theoretical physics which had previously been inaccessible to testing in the lab.

One of these predictions is the so-called tunnel effect, a phenomenon predicted by quantum physics whereby an electron is able to pass through a barrier which, in theory, it does not have the energy to surmount. Although there was some evidence that the tunnel effect existed in nature, it had never yielded to real-time observation. Now, thanks to Corkum and Krausz’s technique, building on L’Huillier’s discovery, it could be seen on “film” for the first time.

In search of applications in fields like electronics and biomedicine

Now that attosecond physics has revealed its unquestionable potential, the awardees wish to use it to delve deeper into the mysteries of the matter all nature is made of, and to develop applications in fields such as electronics or biomedicine.

“This field of research is exploding in every direction,” says L’Huillier. “I have had the privilege to be there from the beginning, so I have seen the ideas grow and been able to follow the main steps in the process.” Asked about its future, she ventures that “it will split into different subfields,” as has occurred with other lines of research close to her own.

For this scientist, the next goal is to move towards the sphere of quantum information science. She is currently studying ways to probe more closely into processes like entanglement, one of the most surprising features of quantum mechanics whereby two separate particles, perhaps even kilometers apart, display a shared behavior that cannot be accounted for by classical physics. Arriving at as close as possible an understanding of this phenomenon could do much to hasten the advancement of quantum technologies, although L’Huillier’s motivation is not of an immediately practical nature: “This is a new aspect which I am very excited about, though I have no idea where it will go.”

Another concern is the highly specialized nature of the lasers used to generate attosecond pulses, and she is currently pondering ways to achieve the same effect using more widespread, commercially available lasers. “I think they are going to be very, very useful for more standard, maybe even industrial applications.”

Corkum, meantime, has been using attosecond pulses generated not by single atoms but by sets of atoms of semiconductors such as silicon. Semiconductors are at the heart of modern electronics, and the scientist believes that combining all previous knowledge of these materials with the new possibility of having them emit attosecond pulses is “a very powerful technology.”

Krausz too believes that attophysics can drive a new revolution in computing: “Electrons play an extremely important role in nanocircuits, they are responsible for switching the electric current on and off and thus processing information at ever higher speeds. If we want to speed up signal processing to build ever more powerful computers, again, we have to understand how electrons move in these tiny dimensions. And in doing so, we have the opportunity to advance electronic signal processing to its ultimate limit.”

He has also been exploring the potential of attosecond pulses in the detection of disease. If we remove all the cells from a blood sample, he explains, the fluid we are left with is the blood plasma or serum (depending on the treatment). The molecules it contains provide valuable cues to the donor’s health status, and the scientist is studying ways to use attosecond pulses to extract this information.

“Using incredibly sensitive measurements, we can analyze these molecules with great precision,” he explains. “And in our preliminary studies, we have been able to detect eight different types of cancers with an excellent efficiency. We have also detected one type of a very severe coronary disease, pre-diabetes, diabetes, and stroke.” These measurements, he believes, could prove game-changing in future for the early diagnosis of multiple conditions.

Results are now being subjected to testing in 10,000 individuals as part of a multi-year clinical trial, and Krausz’s hope is that the system may be operative within the next ten years.


Anne L’HuillierPaul Corkum, and Ferenc Krausz were put forward for the award by Stephen Leone, John R. Thomas Endowed Chair in Physical Chemistry at the University of California, Berkeley (United States); Fernando Martín, Professor of Physical Chemistry at the Universidad Autónoma de Madrid and Scientific Director of the Severo Ochoa project at IMDEA Nanociencia (Spain); and Pascal Salières, Head of the Attophysics Group at CEA Paris-Saclay (French Alternative Energies and Atomic Energy Commission), France.

Laureate bio notes

Anne L’Huillier (Paris, France, 1958), of French-Swedish nationality, obtained a double master’s degree in physics and mathematics in 1979, and went on to receive her PhD in Physical Sciences from the Université Pierre et Marie Curie in Paris in 1986. She completed her doctoral studies at what is now known as the Atomic Energy and Alternative Energies Commission (CEA), a public research organization where she held a permanent research position from 1986 to 1995, combining her work there with postdoc stays at Chalmers University of Technology (Gothenburg), the University of Southern California (Los Angeles) and the Lawrence Livermore National Laboratory (Livermore). In 1995 he joined the faculty at Lund University, where she has been Professor of Atomic Physics since 1997. Leader of eight EU-funded projects since 1993, she was a Member of the Nobel Committee for Physics from 2010 to 2015.

Paul Corkum (Saint John, New Brunswick, Canada, 1943) completed a PhD in Physics at Lehigh University (Bethlehem, Pennsylvania, United States) in 1972. In 1973 he joined the National Research Council of Canada (CNRC), where now, half a century on, he heads the Joint Attosecond Science Laboratory, a partnership between the CNRC and the University of Ottawa, where he is a Distinguished University Professor. He is also Co-Director of the Joint Centre for Extreme Photonics at the University of Ottawa and holds academic positions at Texas A&M University and the University of New Mexico. Author of over 360 articles in scientific journals with more than 47,000 citations, he serves or has served as an advisor to the U.S. National Research Council, the European Research Council and the Engineering and Physical Sciences Research Council (UK).

Ferenc Krausz (Mór, Hungary, 1962), of Hungarian-Austrian nationality, completed two degree courses simultaneously between 1981 and 1985, in electrical engineering at Budapest University of Technology and in theoretical physics at Eötvös Loránd University, also in the Hungarian capital. Shortly after, he moved to Austria and obtained his PhD in Laser Physics from Vienna University of Technology (1991), where he would go on to become a Full Professor of Electrical Engineering (1999-2004). He is currently Professor of Experimental Physics at Ludwig Maximilian University of Munich (since 2004) and one of five directors at the Max Planck Institute of Quantum Optics (since 2003). Krausz is also Scientific Director at the Center for Molecular Fingerprinting in Budapest, as well as heading the Centre for Advanced Laser Applications and the Laboratory for Extreme Photonics, both of them in Munich.

Basic Sciences committee and evaluation support panel

The committee in this category was chaired by Theodor Hänsch, Director of the Division of Laser Spectroscopy at the Max Planck Institute of Quantum Optics (Germany) and the 2005 Nobel Laureate in Physics, with Hongkun Park, Mark Hyman Jr. Professor of Chemistry and Professor of Physics at Harvard University (United States), acting as secretary. Remaining members were Emmanuel Candès, Barnum-Simons Professor of Mathematics and Statistics at Stanford University (United States), María José García Borge, Research Professor at the Institute of the Structure of Matter (IEM), CSIC (Spain), Nigel Hitchin, Emeritus Savilian Professor of Geometry in the Mathematical Institute at the University of Oxford (United Kingdom), Aitziber López Cortajarena, Ikerbasque Research Professor, Scientific Director and Biomolecular Nanotechnology Group Leader at CIC biomaGUNE, Center for Cooperative Research in Biomaterials (Spain), Martin Quack, Head of the Molecular Kinetics and Spectroscopy Group in the Laboratory of Physical Chemistry at ETH Zurich (Switzerland), and Sandip Tiwari, Charles N. Mellowes Professor in Engineering, Emeritus at Cornell University (United States) and Distinguished Visiting Professor at the Indian Institute of Technology, Kanpur (India).

The evaluation support panel charged with nominee pre-assessment was organized into three groups. The Physics Group was coordinated by Marisol Martín González, Scientific Researcher at the Institute of Micro and Nanotechnology (INM-CNM, CSIC) and formed by Alberto Casas González, Research Professor at the Institute for Theoretical Physics (IFT, CSIC-UAM); Alfonso Cebollada Navarro, Research Professor at the Institute of Micro and Nanotechnology (IMN-CNM, CSIC); Lourdes Fábrega Sánchez, Tenured Scientist at the Institute of Materials Science of Barcelona (ICMAB, CSIC); and Alejandro Luque Estepa, Tenured Scientist at the Institute of Astrophysics of Andalusia (IAA, CSIC). The Chemistry Group was coordinated by José M. Mato, General Director of CIC bioGUNE and CIC biomaGUNE, and formed by Miguel Ángel Bañares González, Research Professor in the Institute of Catalysis and Petrochemistry (ICP, CSIC); Ethel Eljarrat Essebag, Scientific Researcher at the Institute of Environmental Assessment and Water Research (IDAEA, CSIC); Francisco García Labiano, Deputy Coordinator of the MATERIA Global Area and Scientific Researcher at the Institute of Carbochemistry (ICB, CSIC); Jesús Jiménez-Barbero, Scientific Director of CIC bioGUNE and Ikerbasque Research Professor in the Chemical Glycobiology Lab; Gonzalo Jiménez-Osés, Principal Investigator in the Computational Chemistry Lab at CIC bioGUNE; Luis Liz-Marzán, Principal Investigator in the Bionanoplasmonics Lab at CIC biomaGUNE; Aitziber López Cortajarena, Ikerbasque Research Professor, Scientific Director and Principal Investigator in the Biomolecular Nanotechnology Lab at CIC biomaGUNE; and María Luz Sanz Murias, Scientific Researcher at the Institute of General Organic Chemistry (IQOG, CSIC). The Mathematics Group was coordinated by José María Martell Berrocal, CSIC Vice-President for Scientific and Technical Research, and formed by María Jesús Carro Rosell, Professor of Mathematical Analysis at the Universidad Complutense de Madrid; Alberto Enciso Carrasco, Research Professor at the Institute of Mathematical Sciences (ICMAT, CSIC); Elisenda Feliú, Associate Professor in the Department of Mathematical Sciences at the University of Copenhagen (Denmark); and Francisco Martín Serrano, Professor in the Department of Geometry and Topology at the University of Granada.

About the BBVA Foundation Frontiers of Knowledge Awards

The BBVA Foundation centers its activity on the promotion of world-class scientific research and cultural creation, and the recognition of talent.

The BBVA Foundation Frontiers of Knowledge Awards, funded with 400,000 euros in each of their eight categories, recognize and reward contributions of singular impact in physics and chemistry, mathematics, biology and biomedicine, technology, environmental sciences (climate change, ecology and conservation biology), economics, social sciences, the humanities and music, privileging those that significantly enlarge the stock of knowledge in a discipline, open up new fields, or build bridges between disciplinary areas. The goal of the awards, established in 2008, is to celebrate and promote the value of knowledge as a public good without frontiers, the best instrument to take on the great global challenges of our time and expand the worldviews of individuals for the benefit of all humanity. Their eight categories address the knowledge map of the 21st century.

The BBVA Foundation has been aided in the evaluation of nominees for the Frontiers Award in Basic Sciences by the Spanish National Research Council (CSIC), the country’s premier public research organization. CSIC has a preferential role in the appointment of members to the evaluation support panels made up of leading experts in the corresponding knowledge area, who are charged with undertaking an initial assessment of the candidates proposed by numerous institutions across the world, and drawing up a reasoned shortlist for the consideration of the award committees. CSIC is also responsible for designating each committee’s chair and participates in the selection of remaining members, thus helping to ensure objectivity in the recognition of scientific excellence.

The BBVA Foundation Frontiers of Knowledge Award in Basic Sciences goes in this fifteenth edition to Anne L’Huillier (Lund University, Sweden), Paul Corkum (University of Ottawa, Canada) and Ferenc Krausz (Max Planck Institute of Quantum Optics, Germany), the three pioneers of “attosecond physics” or “attophysics” whose work has made it possible to observe subatomic processes unfolding over the shortest time scale captured by science.


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Potential to locate life on Mars with Artificial Intelligence – Innovation News Network



An international team of researchers has found that Artificial Intelligence (AI) can help identify hidden patterns within geographical data that could indicate life on Mars.  

As there are only a few opportunities to collect samples from Mars in the search for life beyond Earth, it is crucial that these missions target locations that have the best chance of harbouring extra-terrestrial life. The new study, led by an international team of over 50 researchers, ensures that this can be supported by using Artificial Intelligence and Machine Learning methods. This technology can be used to identify hidden patterns within geographical data that could indicate the presence of life on Mars. 

The work, ‘Orbit-to-Ground Framework to Decode and Predict Biosignature Patterns in Terrestrial Analogues,’ has been published in Nature Astronomy.  

The resulting model was capable of locating biosignatures that have the potential to indicate life on Mars 

The first part of the study, led by Dr Kimberley Warren-Rhodes at the SETI Institute, was an ecological survey of a 3 km² area in the Salar de Pajonales basin, at the boundary of the Chilean Atacama Desert and Altiplano in South America. This was used to map the distribution of photosynthetic microorganisms. Gene sequencing and infrared spectroscopy were also used to reveal distinct markers of life, called ‘biosignatures.’ Aerial images were then combined with this data to train a Machine Learning model to predict which macro- and microhabitat types would be associated with biosignatures that could indicate life on Mars and other areas. 


The resulting model could locate and detect biosignatures up to 87.5% of the time on data on which it was not trained. This decreased the search area required to find a positive result by up to 97%. In the future, life on Mars could be detected through the identification of the areas most likely to contain signs of life. These can then be extensively searched by rovers. 

© shutterstock

Dr Freddie Kalaitzis from the University of Oxford’s Department of Computer Science led the application of Machine Learning methods to microhabitat data. He said: “This work demonstrates an AI-guided protocol for searching for life on a Mars-like terrestrial analogue on Earth. This protocol is the first of its kind trained on actual field data, and its application can, in principle, generalise to other extreme life-harbouring environments. Our next steps will be to test this method further on Earth with the aim that it will eventually aid our exploration for biosignatures elsewhere in the solar system, such as Mars, Titan, and Europa.” 

On Earth, one of the most similar analogues to Mars is the Pajonales, a four-million-year-old lakebed. This area is considered to be inhospitable to most forms of life. Comparable to the evaporitic basins of Mars, the high altitude (3,541 m) basin experiences exceptionally strong levels of ultraviolet radiation, hypersalinity, and low temperatures. 

Water availability is likely to be the key factor determining the position of biological hotspots 

The researchers collected over 7,700 images and 1,150 samples and tested for the presence of photosynthetic microbes living within the salt domes, rocks, and alabaster crystals that make up the basin’s surface. Here, biosignature markers, such as carotenoid and chlorophyll pigments, could be seen as orange-pink and green layers respectively. 

Ground sampling data and 3D topographical mapping were combined with the drone images to classify regions into four macrohabitats (metre to kilometre scales) and six microhabitats (centimetre scale). The team found that the microbial organisms across the study site were clustered in distinct regions, despite the Pajonales having a near-uniform mineral composition.  

Follow-up experiments showed that rather than environmental variables, like nutrient or light availability, determining the position of, biological hotspots water availability is the most likely factor.  

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The combined dataset was used to train convolutional neural networks to predict which macro- and microhabitats were most strongly associated with biosignatures.  

“For both the aerial images and ground-based centimetre-scale data, the model demonstrated high predictive capability for the presence of geological materials strongly likely to contain biosignatures,” said Dr Kalaitzis.  

“The results aligned well with ground-truth data, with the distribution of biosignatures being strongly associated with hydrological features.” 

The model will be used to map other harsh ecosystems  

Now, the researchers aim to test the model’s ability to predict the location of similar yet different natural systems in the Pajonales basin, such as ancient stromatolite fossils. The model will also be used to map other harsh ecosystems, including hot springs and permafrost soils. The data from these studies will inform and test hypotheses on the mechanisms that living organisms use to survive in extreme environments. 

“Our study has once again demonstrated the power of Machine Learning methods to accelerate scientific discovery through its ability to analyse immense volumes of different data and identify patterns that would be indiscernible to a human being,” Dr Kalaitzis added.  

“Ultimately, we hope the approach will facilitate the compilation of a databank of biosignature probability and habitability algorithms, roadmaps, and models that can serve as a guide for exploration of life on Mars.” 

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By cracking a metal 3D-printing conundrum, researchers propel the technology toward widespread application – EurekAlert



image: Researchers used high-speed X-ray diffraction to identify the crystal structures that form within steel as it is 3D-printed. The angle at which the X-rays exit the metal correspond to types of crystal structures within.
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Credit: H. König et al. via Creative Commons (, adapted by N. Hanacek/NIST

Researchers have not yet gotten the additive manufacturing, or 3D printing, of metals down to a science completely. Gaps in our understanding of what happens within metal during the process have made results inconsistent. But a new breakthrough could grant an unprecedented level of mastery over metal 3D printing. 

Using two different particle accelerator facilities, researchers at the National Institute of Standards and Technology (NIST), KTH Royal Institute of Technology in Sweden and other institutions have peered into the internal structure of steel as it was melted and then solidified during 3D printing. The findings, published in Acta Materialia, unlock a computational tool for 3D-printing professionals, offering them a greater ability to predict and control the characteristics of printed parts, potentially improving the technology’s consistency and feasibility for large-scale manufacturing.   

A common approach for printing metal pieces involves essentially welding pools of powdered metal with lasers, layer by layer, into a desired shape. During the first steps of printing with a metal alloy, wherein the material rapidly heats up and cools off, its atoms — which can be a smattering of different elements — pack into ordered, crystalline formations. The crystals determine the properties, such as toughness and corrosion resistance, of the printed part. Different crystal structures can emerge, each with their own pros and cons. 


“Basically, if we can control the microstructure during the initial steps of the printing process, then we can obtain the desired crystals and, ultimately, determine the performance of additively manufactured parts,” said NIST physicist Fan Zhang, a study co-author. 

While the printing process wastes less material and can be used to produce more complicated shapes than traditional manufacturing methods, researchers have struggled to grasp how to steer metal toward particular kinds of crystals over others.  

This lack of knowledge has led to less than desirable results, such as parts with complex shapes cracking prematurely thanks to their crystal structure.  

“Among the thousands of alloys that are commonly manufactured, only a handful can be made using additive manufacturing,” Zhang said. 

Part of the challenge for scientists has been that solidification during metal 3D printing occurs in the blink of an eye.  

To capture the high-speed phenomenon, the authors of the new study employed powerful X-rays generated by cyclic particle accelerators, called synchrotrons, at Argonne National Laboratory’s Advanced Photon Source and the Paul Scherrer Institute’s Swiss Light Source.  

The team sought to learn how the cooling rates of metal, which can be controlled by laser power and movement settings, influence crystal structure. Then the researchers would compare the data to the predictions of a widely used computational model developed in the ’80s that describes the solidification of alloys.  

While the model is trusted for traditional manufacturing processes, the jury has been out on its applicability in the unique context of 3D printing’s rapid temperature shifts.  

“Synchrotron experiments are time consuming and expensive, so you cannot run them for every condition that you’re interested in. But they are very useful for validating models that you then can use to simulate the interesting conditions,” said study co-author Greta Lindwall, an associate professor of materials science and engineering at KTH Royal Institute of Technology. 

Within the synchrotrons, the authors set up additive manufacturing conditions for hot-work tool steel — a kind of metal used to make, as the name suggests, tools that can withstand high temperatures.  

As lasers liquified the metal and different crystals emerged, X-ray beams probed the samples with enough energy and speed to produce images of the fleeting process. The team members required two separate facilities to support the cooling rates they wanted to test, which ranged from temperatures of tens of thousands to more than a million kelvins per second.  

The data the researchers collected depicted the push and pull between two kinds of crystal structures, austenite and delta ferrite, the latter being associated with cracking in printed parts. As cooling rates surpassed 1.5 million kelvins (2.7 million degrees Fahrenheit) per second, austenite began to dominate its rival. This critical threshold lined up with what the model foretold.  

“The model and the experimental data are nicely in agreement. When we saw the results, we were really excited,” Zhang said.  

The model has long been a reliable tool for materials design in traditional manufacturing, and now the 3D-printing space may be afforded the same support.  

The results indicate that the model can inform scientists and engineers on what cooling rates to select for the early solidification steps of the printing process. That way the optimal crystal structure would appear within their desired material, making metal 3D printing less of a roll of the dice.  

“If we have data, we can use it to validate the models. That’s how you accelerate the widespread adoption of additive manufacturing for industrial use,” Zhang said.

Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.

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Deep Impact: Heat Waves Happen at the Bottom of the Ocean Too



This visualization depicts bathymetric features of the western Atlantic Ocean Basin, including the continental shelf, captured by satellite. Credit: NOAA’s National Environmental Satellite and Information Service


First assessment of bottom marine heat waves opens a window on the deep.

The 2013-2016 marine heat wave known as “The Blob” warmed a vast expanse of surface waters across the northeastern Pacific, disrupting West Coast marine ecosystems, depressing salmon returns, and damaging commercial fisheries. It also prompted a wave of research on extreme warming of ocean surface waters.


But, as new research from the National Oceanic and Atmospheric Administration (<span class=”glossaryLink” aria-describedby=”tt” data-cmtooltip=”

The National Oceanic and Atmospheric Administration (NOAA) is a scientific agency of the United States government that is focused on understanding and predicting changes in Earth’s oceans, atmosphere, and climate. It is headquartered in Silver Spring, Maryland and is a part of the Department of Commerce. NOAA conducts research and provides information, products, and services that are used to protect life and property, and to support economic growth and development. It also works to conserve and manage natural resources, including fisheries, wildlife, and habitats. Some of the specific activities that NOAA is involved in include weather forecasting, climate monitoring, marine biology and fisheries research, and satellite and remote sensing.


In a paper published in the journal <span class=”glossaryLink” aria-describedby=”tt” data-cmtooltip=”

Nature Communications
&lt;em&gt;Nature Communications&lt;/em&gt; is a peer-reviewed, open-access, multidisciplinary, scientific journal published by Nature Portfolio. It covers the natural sciences, including physics, biology, chemistry, medicine, and earth sciences. It began publishing in 2010 and has editorial offices in London, Berlin, New York City, and Shanghai.&nbsp;

” data-gt-translate-attributes=”[“attribute”:”data-cmtooltip”, “format”:”html”]”>Nature Communications on March 13, a team led by NOAA researchers used a combination of observations and computer models to generate the first broad assessment of bottom marine heat waves in the productive continental shelf waters surrounding North America.

Endangered Fish Marine Heat Waves

Marine heat waves have a significant impact on ocean ecosystems globally, disrupting the productivity and distribution of organisms, from plankton to whales. There is a significant effort to study, track, and predict the timing, intensity, duration, and physical drivers of these events. Credit: NOAA Fisheries


“Researchers have been investigating marine heat waves at the sea surface for over a decade now,” said lead author Dillon Amaya, a research scientist with NOAA’s Physical Science Laboratory. “This is the first time we’ve been able to really dive deeper and assess how these extreme events unfold along shallow seafloors.”


Marine heat waves dramatically impact the health of ocean ecosystems around the globe, disrupting the productivity and distribution of organisms as small as plankton and as large as whales. As a result, there has been a considerable effort to study, track and predict the timing, intensity, duration, and physical drivers of these events.

Most of that research has focused on temperature extremes at the ocean’s surface, for which there are many more high-quality observations taken by satellites, ships, and buoys. Sea surface temperatures can also be indicators for many physical and biochemical ocean characteristics of sensitive marine ecosystems, making analyses more straightforward.

About 90% of the excess heat from global warming has been absorbed by the ocean, which has warmed by about 1.5C over the past century. Marine heatwaves have become about 50% more frequent over the past decade.

Ling Cod Humboldt Bay Jetty in California

Ling cod, like this one caught off of Humboldt Bay Jetty in California, are a member of Pacific groundfish communities vulnerable to impacts from bottom marine heat waves. Credit: Nicholas Easterbrook/NOAA Fisheries


In recent years, scientists have increased efforts to investigate marine heat waves throughout the water column using the limited data available. But previous research didn’t target temperature extremes on the ocean bottom along continental shelves, which provide critical habitat for important commercial <span class=”glossaryLink” aria-describedby=”tt” data-cmtooltip=”

A species is a group of living organisms that share a set of common characteristics and are able to breed and produce fertile offspring. The concept of a species is important in biology as it is used to classify and organize the diversity of life. There are different ways to define a species, but the most widely accepted one is the biological species concept, which defines a species as a group of organisms that can interbreed and produce viable offspring in nature. This definition is widely used in evolutionary biology and ecology to identify and classify living organisms.

Due to the relative scarcity of bottom-water temperature datasets, the scientists used a data product called “reanalysis” to conduct the assessment, which starts with available observations and employs computer models that simulate ocean currents and the influence of the atmosphere to “fill in the blanks.” Using a similar technique, NOAA scientists have been able to reconstruct global weather back to the early 19th century.

Average Intensity of Ocean Bottom Heat Waves

These illustrations show the average intensity of bottom heat waves ( heat anomalies) that occurred between 1993 and 2019 in each of the large marine ecosystems studied by a team of NOAA scientists. Credit: NOAA Physical Sciences Laboratory


While ocean reanalyses have been around for a long time, they have only recently become skillful enough and have high enough resolution to examine ocean features, including bottom temperatures, near the coast.


The research team, from NOAA, Cooperative Institute for Research in Environmental Sciences (CIRES), and National Center for Atmospheric Research (NCAR), found that on the continental shelves around North America, bottom marine heat waves tend to persist longer than their surface counterparts, and can have larger warming signals than the overlying surface waters. Bottom and surface marine heat waves can occur simultaneously in the same location, especially in shallower regions where surface and bottom waters mingle.

Lionfish Invasive Species

Lionfish have become a poster child for invasive species issues in the western north Atlantic region. Their populations continue to expand, threatening the well-being of coral reefs and other marine ecosystems. This includes the commercially and recreationally important fish that depend on them. Credit: NOAA Fisheries


But bottom marine heat waves can also occur with little or no evidence of warming at the surface, which has important implications for the management of commercially important fisheries. “That means it can be happening without managers realizing it until the impacts start to show,” said Amaya.

In 2015, a combination of harmful algal blooms and loss of kelp forest habitat off the West Coast of the United States—both caused by The Blob – led to closures of shellfisheries that cost the economy in excess of $185 million, according to a 2021 study. The commercial tri-state Dungeness crab fishery recorded a loss of $97.5 million, affecting both tribal and nontribal fisheries. Washington and Californian coastal communities lost a combined $84 million in tourist spending due to the closure of recreational razor clam and abalone fisheries.


In 2021, a groundfish survey published by NOAA Fisheries indicated that Gulf of Alaska cod had plummeted during The Blob, experiencing a 71% decline in abundance between 2015 and 2017. On the other hand, young groundfish and other marine creatures in the Northern California Current system thrived under the unprecedented ocean conditions, a 2019 paper by Oregon State University and NOAA Fisheries researchers found.

Unusually warm bottom water temperatures have also been linked to the expansion of invasive lionfish along the southeast U.S., coral bleaching and subsequent declines of reef fish, changes in survival rates of young Atlantic cod, and the disappearance of near-shore lobster populations in southern New England.

The authors say it will be important to maintain existing continental shelf monitoring systems and to develop new real-time monitoring capabilities to alert marine resource managers to bottom warming conditions.

“We know that early recognition of marine heat waves is needed for proactive management of the coastal ocean,” said co-author Michael Jacox, a research oceanographer who splits his time between NOAA’s Southwest Fisheries Science Center and the Physical Sciences Laboratory. “Now it’s clear that we need to pay closer attention to the ocean bottom, where some of the most valuable species live and can experience heat waves quite different from those on the surface.”


Reference: “Bottom marine heatwaves along the continental shelves of North America” by Dillon J. Amaya, Michael G. Jacox, Michael A. Alexander, James D. Scott, Clara Deser, Antonietta Capotondi and Adam S. Phillips, 13 March 2023, Nature Communications.
DOI: 10.1038/s41467-023-36567-0



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