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News Article | May 12, 2017
Site: www.eurekalert.org

Scientists have discovered a way to solve a problem that has baffled humans for so long it is mentioned in the Bible: achieving the most efficient packing of objects such as grains and pharmaceutical drugs. Lead researcher Dr Mohammad Saadatfar from The Australian National University (ANU) said the knowledge could be vital for building skyscrapers on sand, understanding how grains were stored in silos, or how drugs were packed and delivered to specific targets in the body. "It's crazy - sand is one of the most common building materials in the world and drugs are often packed in the forms of pills, but we really don't understand how assembly of grains or pills behave," said Dr Saadatfar from the ANU Research School of Physics and Engineering. The international team of physicists and mathematicians used high-resolution CT scans to reveal how spherical particles in a disordered arrangement settle and compact themselves into ordered patterns. "Now we believe that we have uncovered the mechanisms underlying the transition from disordered packing of grains to ordered structures," he said. "Whenever spheres - such as soccer balls, ball bearings or atoms - are packed into a space, the most efficient packing is in a very ordered pattern, known as face-centred cubic. "Sodium and chloride atoms in salt crystals are also arranged and ordered that way." When organised that way, the spheres had a minimum of gaps between them, taking up just over 74 per cent of the space, Dr Saadatfar said. "However, when settling quickly, spheres don't naturally form that arrangement, reaching only 64 per cent at best, an arrangement known as random closed packing," he said. The team had previously shown that the 64 per cent packing is not a random arrangement. In fact, spheres tend to form into tightly-held arrangements of tetrahedra self-organised in rings of five. "For a long time, scientists thought that packing spheres more efficiently was impossible to occur naturally and extremely difficult to observe in the lab," Dr Saadatfar said. "That's because it's hard to move to the perfectly ordered structure. It requires breaking the disordered patterns that developed naturally and that are mechanically robust. "You need to add just the right amount of energy for that - too little energy and the packing remains disordered, too much, the crystal will not form either." Dr Saadatfar said the transition to a tighter packing arrangement was mentioned in the Bible. "Luke 6:38 states 'A good measure, pressed down, shaken together and running over, will be poured into your lap. For with the measure you use, it will be measured to you.' It mentions all the experimental protocols that we used in lab - pressing down, shaking, pouring," Dr Saadatfar said. "I'm not sure the authors of the Bible had nailed the mathematical basis of it." The team used the relatively new field of mathematics known as homology to interpret 3D x-ray microscope images and large-scale computer simulations. Dr Saadatfar said for different particle shapes, the mathematics became much more complex. "When you look at footballs or M&Ms we've got a lot of work to do," Dr Saadatfar said. "I'll be keeping my department supplied with M&Ms for the next few years." The paper, titled 'Pore configuration landscape of granular crystallisation', is published in Nature Communications (DOI:10.1038/NCOMMS15082).


News Article | May 12, 2017
Site: phys.org

Lead researcher Dr Mohammad Saadatfar from The Australian National University (ANU) said the knowledge could be vital for building skyscrapers on sand, understanding how grains were stored in silos, or how drugs were packed and delivered to specific targets in the body. "It's crazy - sand is one of the most common building materials in the world and drugs are often packed in the forms of pills, but we really don't understand how assembly of grains or pills behave," said Dr Saadatfar from the ANU Research School of Physics and Engineering. The international team of physicists and mathematicians used high-resolution CT scans to reveal how spherical particles in a disordered arrangement settle and compact themselves into ordered patterns. "Now we believe that we have uncovered the mechanisms underlying the transition from disordered packing of grains to ordered structures," he said. "Whenever spheres - such as soccer balls, ball bearings or atoms - are packed into a space, the most efficient packing is in a very ordered pattern, known as face-centred cubic. "Sodium and chloride atoms in salt crystals are also arranged and ordered that way." When organised that way, the spheres had a minimum of gaps between them, taking up just over 74 per cent of the space, Dr Saadatfar said. "However, when settling quickly, spheres don't naturally form that arrangement, reaching only 64 per cent at best, an arrangement known as random closed packing," he said. The team had previously shown that the 64 per cent packing is not a random arrangement. In fact, spheres tend to form into tightly-held arrangements of tetrahedra self-organised in rings of five. "For a long time, scientists thought that packing spheres more efficiently was impossible to occur naturally and extremely difficult to observe in the lab," Dr Saadatfar said. "That's because it's hard to move to the perfectly ordered structure. It requires breaking the disordered patterns that developed naturally and that are mechanically robust. "You need to add just the right amount of energy for that - too little energy and the packing remains disordered, too much, the crystal will not form either." Dr Saadatfar said the transition to a tighter packing arrangement was mentioned in the Bible. "Luke 6:38 states 'A good measure, pressed down, shaken together and running over, will be poured into your lap. For with the measure you use, it will be measured to you.' It mentions all the experimental protocols that we used in lab - pressing down, shaking, pouring," Dr Saadatfar said. "I'm not sure the authors of the Bible had nailed the mathematical basis of it." The team used the relatively new field of mathematics known as homology to interpret 3-D x-ray microscope images and large-scale computer simulations. Dr Saadatfar said for different particle shapes, the mathematics became much more complex. "When you look at footballs or M&Ms we've got a lot of work to do," Dr Saadatfar said. "I'll be keeping my department supplied with M&Ms for the next few years." More information: M. Saadatfar et al. Pore configuration landscape of granular crystallization, Nature Communications (2017). DOI: 10.1038/ncomms15082


News Article | May 10, 2017
Site: astrobiology.com

Zircon crystals as old as 4.4 billion years were found in sandstone at Jack Hills of Western Australia. Credit: Stuart Hay, ANU ANU scientists say the early Earth was likely to be barren, mountainless and almost entirely under water with a few small islands, following their analysis of tiny mineral grains as old as 4.4 billion years. Lead researcher Dr Antony Burnham said the team studied zircon mineral grains that were preserved in sandstone rocks in the Jack Hills of Western Australia and which were the oldest fragments of the Earth ever found. "The history of the Earth is like a book with its first chapter ripped out with no surviving rocks from the very early period, but we've used these trace elements of zircon to build a profile of the world at that time," said Dr Burnham from the ANU Research School of Earth Sciences. "Our research indicates there were no mountains and continental collisions during Earth's first 700 million years or more of existence - it was a much more quiet and dull place. "Our findings also showed that there are strong similarities with zircon from the types of rocks that predominated for the following 1.5 billion years, suggesting that it took the Earth a long time to evolve into the planet that we know today." Dr Burnham said the zircon grains that eroded out of the oldest rocks were like skin cells found at a crime scene. "We used the granites of southeast Australia to decipher the link between zircon composition and magma type, and built a picture of what those missing rocks were," he said. The first known form of life emerged some time later, around 3.8 billion years ago. Dr Burnham said the zircon formed by melting older igneous rocks rather than sediments. "Sediment melting is characteristic of major continental collisions, such as the Himalayas, so it appears that such events did not occur during these early stages of Earth's history," he said. Dr Burnham said scientists in the field were able to build on each other's work to gain a better understanding of early Earth. "The samples of zircon from Jack Hills have been collected over the course of several decades by many people, while chemical analyses carried out by an ANU research group 20 years ago have proved invaluable," he said. The study, 'Formation of Hadean granites by melting of igneous crust', is published in Nature Geoscience.


News Article | May 17, 2017
Site: www.cemag.us

Engineers have invented tiny structures inspired by butterfly wings that open the door to new solar cell technologies and other applications requiring precise manipulation of light. The inspiration comes from the blue Morpho Didius butterfly, which has wings with tiny cone-shaped nanostructures that scatter light to create a striking blue iridescence, and could lead to other innovations such as stealth and architectural applications. Lead researcher Dr. Niraj Lal from the Australian National University Research School of Engineering says the team made similar structures at the nanoscale and applied the same principles in the butterfly wing phenomenon to finely control the direction of light in experiments. "There's a whole bunch of potential new applications using our light-control technique, including next-generation solar cell, architectural and stealth technologies," says Lal. He said scientists can greatly improve the efficiency of solar cells with effective light management. "Techniques to finely control the scattering, reflection and absorption of different colors of light are being used in the next generation of very high-efficiency solar panels," he says. "Being able to make light go exactly where you want it to go has proven to be tricky up until now." Lal says the aim was to absorb all of the blue, green and ultraviolet colors of sunlight in the perovskite layer of a solar cell, and all of the red, orange and yellow light in the silicon layer — known as a tandem solar cell with double-decker layers. Researchers at the ANU surpassed silicon efficiency records with such a cell last month. He says the technique could one day be used to make opaque objects transparent to certain colors, and vice versa, as part of new stealth applications. "We were surprised by how well our tiny cone-shaped structures worked to direct different colors of light where we wanted them to go," Lal says. He says the technique could also be used in architecture to control how much light and heat passed through windows. "Using our approach, a window could be designed to be transparent to some colors non-see through and matt textured for others — so there are very cool potential applications in architecture," Lal says. The technique was very scalable and did not require expensive technology, he says. "These intricate nanostructures grow and assemble themselves — it's not by precise control with a tiny laser or electrons," Lal says. The research paper is published in ACS Photonics, with co-authors Kevin Le, Andrew Thomson, Maureen Brauers, Tom White, and Kylie Catchpole.


News Article | May 17, 2017
Site: www.chromatographytechniques.com

Engineers have invented tiny structures inspired by butterfly wings that open the door to new solar cell technologies and other applications requiring precise manipulation of light. The inspiration comes from the blue Morpho Didius butterfly, which has wings with tiny cone-shaped nanostructures that scatter light to create a striking blue iridescence, and could lead to other innovations such as stealth and architectural applications. Lead researcher Niraj Lal, from the ANU Research School of Engineering said the team made similar structures at the nanoscale and applied the same principles in the butterfly wing phenomenon to finely control the direction of light in experiments. "There's a whole bunch of potential new applications using our light-control technique, including next-generation solar cell, architectural and stealth technologies," said Lal. He said scientists can greatly improve the efficiency of solar cells with effective light management. "Techniques to finely control the scattering, reflection and absorption of different colors of light are being used in the next generation of very high-efficiency solar panels," he said. "Being able to make light go exactly where you want it to go has proven to be tricky up until now." Lal said the aim was to absorb all of the blue, green and ultraviolet colors of sunlight in the perovskite layer of a solar cell, and all of the red, orange and yellow light in the silicon layer - known as a tandem solar cell with double-decker layers. Researchers at the ANU surpassed silicon efficiency records with such a cell last month. He said the technique could one day be used to make opaque objects transparent to certain colors, and vice versa, as part of new stealth applications. "We were surprised by how well our tiny cone-shaped structures worked to direct different colors of light where we wanted them to go," Lal said. He said the technique could also be used in architecture to control how much light and heat passed through windows. "Using our approach, a window could be designed to be transparent to some colors non-see through and matt textured for others - so there are very cool potential applications in architecture," Lal said. The technique was very scalable and did not require expensive technology, he said. "These intricate nanostructures grow and assemble themselves - it's not by precise control with a tiny laser or electrons," Lal said. The research paper is published in ACS Photonics, with co-authors Kevin Le, Andrew Thomson, Maureen Brauers, Tom White and Kylie Catchpole.


Antimatter is material composed of the antiparticle partners of ordinary matter – when antimatter meets with matter, they quickly annihilate each other to form a burst of energy in the form of gamma-rays. Scientists have known since the early 1970s that the inner parts of the Milky Way galaxy are a strong source of gamma-rays, indicating the existence of antimatter, but there had been no settled view on where the antimatter came from. ANU researcher Dr Roland Crocker said the team had shown that the cause was a series of weak supernova explosions over millions of years, each created by the convergence of two white dwarfs which are ultra-compact remnants of stars no larger than two suns. "Our research provides new insight into a part of the Milky Way where we find some of the oldest stars in our galaxy," said Dr Crocker from the ANU Research School of Astronomy and Astrophysics. Dr Crocker said the team had ruled out the supermassive black hole at the centre of the Milky Way and the still-mysterious dark matter as being the sources of the antimatter. He said the antimatter came from a system where two white dwarfs form a binary system and collide with each other. The smaller of the binary stars loses mass to the larger star and ends its life as a helium white dwarf, while the larger star ends as a carbon-oxygen white dwarf. "The binary system is granted one final moment of extreme drama: as the white dwarfs orbit each other, the system loses energy to gravitational waves causing them to spiral closer and closer to each other," Dr Crocker said. He said once they became too close the carbon-oxygen white dwarf ripped apart the companion star whose helium quickly formed a dense shell covering the bigger star, quickly leading to a thermonuclear supernova that was the source of the antimatter. The research is published in Nature Astronomy. Explore further: Are there antimatter galaxies? More information: "Diffuse Galactic Antimatter from Faint Thermonuclear Supernovae in Old Stellar Populations," Roland M. Crocker et al., 2017 May 22, Nature Astronomy, nature.com/articles/doi:10.1038/s41550-017-0135


The inspiration comes from the blue Morpho Didius butterfly, which has wings with tiny cone-shaped nanostructures that scatter light to create a striking blue iridescence, and could lead to other innovations such as stealth and architectural applications. Lead researcher Dr Niraj Lal from the ANU Research School of Engineering said the team made similar structures at the nanoscale and applied the same principles in the butterfly wing phenomenon to finely control the direction of light in experiments. "There's a whole bunch of potential new applications using our light-control technique, including next-generation solar cell, architectural and stealth technologies," said Dr Lal from the ANU Research School of Engineering. He said scientists can greatly improve the efficiency of solar cells with effective light management. "Techniques to finely control the scattering, reflection and absorption of different colours of light are being used in the next generation of very high-efficiency solar panels," he said. "Being able to make light go exactly where you want it to go has proven to be tricky up until now." Dr Lal said the aim was to absorb all of the blue, green and ultraviolet colours of sunlight in the perovskite layer of a solar cell, and all of the red, orange and yellow light in the silicon layer - known as a tandem solar cell with double-decker layers. Researchers at the ANU surpassed silicon efficiency records with such a cell last month. He said the technique could one day be used to make opaque objects transparent to certain colours, and vice versa, as part of new stealth applications. "We were surprised by how well our tiny cone-shaped structures worked to direct different colours of light where we wanted them to go," Dr Lal said. He said the technique could also be used in architecture to control how much light and heat passed through windows. "Using our approach, a window could be designed to be transparent to some colours non-see through and matt textured for others - so there are very cool potential applications in architecture," Dr Lal said. The technique was very scalable and did not require expensive technology, he said. "These intricate nanostructures grow and assemble themselves - it's not by precise control with a tiny laser or electrons," Dr Lal said. The research paper is published in ACS Photonics, with co-authors Kevin Le, Andrew Thomson, Maureen Brauers, Tom White and Kylie Catchpole. Explore further: New way to make low-cost solar cell technology More information: Niraj N. Lal et al. Transparent Long-Pass Filter with Short-Wavelength Scattering Based onButterfly Nanostructures, ACS Photonics (2017). DOI: 10.1021/acsphotonics.6b01007


News Article | May 15, 2017
Site: www.cemag.us

Australian National University researchers have developed a suitable material to allow brain cells to grow and form predictable circuits, which could lead to the development of prosthetics for the brain. Researchers grew the brain cells on a semiconductor wafer patterned with nanowires which act as a scaffold to guide the growth of brain cells. Lead researcher Dr. Vini Gautam from the Research School of Engineering at ANU says the scaffold provides a platform to study the growth of the brain cells and how they connect with each other. "The project will provide new insights into the development of neuro-prosthetics which can help the brain recover after damage due to an accident, stroke or degenerative neurological diseases," Gautam says. The study is the first to show the neuronal circuits grown on the nanowire scaffolds were functional and highly interconnected, opening the potential to apply their scaffold design for neuro-prosthetics. Project group leader Dr. Vincent Daria from The John Curtin School of Medical Research hopes to use the brain on a chip to understand how neurons in the brain form computing circuits and eventually process information. "Unlike other prosthetics like an artificial limb, neurons need to connect synaptically, which form the basis of information processing in the brain during sensory input, cognition, learning and memory," Daria says. "Using a particular nanowire geometry, we have shown that the neurons are highly interconnected and predictably form functional circuits." Daria says it was important to build up the appropriate environment where neurons can be predictably connected into functional circuits. "We were able to make predictive connections between the neurons and demonstrated them to be functional with neurons firing synchronously," he says. "This work could open up new research model that builds up a stronger connection between materials nanotechnology with neuroscience." The research was a multi-disciplinary collaboration between physics, engineering, and neuroscience. The nanowires were fabricated by a group led by Professor Chennupati Jagadish at the Research School of Physics and Engineering at ANU. The research has been published in Nano Letters.


News Article | May 23, 2017
Site: spaceref.com

A team of international astrophysicists led by The Australian National University (ANU) has shown how most of the antimatter in the Milky Way forms. Antimatter is material composed of the antiparticle partners of ordinary matter -- when antimatter meets with matter, they quickly annihilate each other to form a burst of energy in the form of gamma-rays. Scientists have known since the early 1970s that the inner parts of the Milky Way galaxy are a strong source of gamma-rays, indicating the existence of antimatter, but there had been no settled view on where the antimatter came from. ANU researcher Dr. Roland Crocker said the team had shown that the cause was a series of weak supernova explosions over millions of years, each created by the convergence of two white dwarfs which are ultra-compact remnants of stars no larger than two Suns. "Our research provides new insight into a part of the Milky Way where we find some of the oldest stars in our galaxy," said Dr. Crocker from the ANU Research School of Astronomy and Astrophysics. Dr. Crocker said the team had ruled out the supermassive black hole at the centre of the Milky Way and the still-mysterious dark matter as being the sources of the antimatter. He said the antimatter came from a system where two white dwarfs form a binary system and collide with each other. The smaller of the binary stars loses mass to the larger star and ends its life as a helium white dwarf, while the larger star ends as a carbon-oxygen white dwarf. "The binary system is granted one final moment of extreme drama: as the white dwarfs orbit each other, the system loses energy to gravitational waves causing them to spiral closer and closer to each other," Dr. Crocker said. He said once they became too close the carbon-oxygen white dwarf ripped apart the companion star whose helium quickly formed a dense shell covering the bigger star, quickly leading to a thermonuclear supernova that was the source of the antimatter. Reference: "Diffuse Galactic Antimatter from Faint Thermonuclear Supernovae in Old Stellar Populations," Roland M. Crocker et al., 2017 May 22, Nature Astronomy [https://www.nature.com/articles/s41550-017-0135]. Please follow SpaceRef on Twitter and Like us on Facebook.


News Article | May 16, 2017
Site: news.yahoo.com

Calling all citizen scientists: The Australian National University wants you to join the search for supernovae. Brad Tucker from the ANU Research School of Astronomy and Astrophysics says it’s not possible for one team of researchers to check for exploding stars all the time, but if thousands of people are keeping watch, scientists are sure to get quicker and timelier data. “With the power of the people, we can check these images in minutes and get another telescope to follow up,” Tucker said in a news release. Time is of the essence when it comes to hunting for supernovae. University of Washington astrophysicist Melissa Graham, who studies Type Ia supernovae, says that a star can become more than a billion times brighter when it explodes. But that light fades fast. “After two weeks, they are only 30 percent as bright as they were at peak,” she said. Graham says some telescopes may not be as sensitive as others, and may only detect distant and faint supernovae for about a week after the explosion. To join ANU’s quest, visit Zooniverse.org and head to SkyMapper Sighting. The project has more than 450 volunteers so far. Volunteers can compare images taken over time by SkyMapper, an Australian 1.3-meter telescope surveying the southern sky, and report any changes. As a reward, the first person to correctly discover a supernova will get public recognition as a co-discoverer. Like a similar project called Supernova Hunters, SkyMapper Sighting relies on humans to identify supernovae because our eyes and brains are better at recognizing the proper patterns than computer programs are. Tucker and his colleagues hope to measure the acceleration of the universe’s growth by using the exploding stars as markers. He compares supernovae to light bulbs: If you have light bulbs lined up down a road, the one closest to you will look brighter than the one farthest away. “If you know how bright your bulb is, and how bright your bulb should be, you can calculate that difference, and that difference is a distance,” Tucker explained in a video.

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