‘Elegant’ solution reveals how the universe got its structure

The universe is full of billions of galaxies — but their distribution across space is far from uniform. Why do we see so much structure in the universe today and how did it all form and grow?

A 10-year survey of tens of thousands of galaxies made using the Magellan Baade Telescope at Carnegie’s Las Campanas Observatory in Chile provided a new approach to answering this fundamental mystery. The results, led by Carnegie’s Daniel Kelson, are published in Monthly Notices of the Royal Astronomical Society.

“How do you describe the indescribable?” asks Kelson. “By taking an entirely new approach to the problem.”

“Our tactic provides new — and intuitive — insights into how gravity drove the growth of structure from the universe’s earliest times,” said co-author Andrew Benson. “This is a direct, observation-based test of one of the pillars of cosmology.”

The Carnegie-Spitzer-IMACS Redshift Survey was designed to study the relationship between galaxy growth and the surrounding environment over the last 9 billion years, when modern galaxies’ appearances were defined.

The first galaxies were formed a few hundred million years after the Big Bang, which started the universe as a hot, murky soup of extremely energetic particles. As this material expanded outward from the initial explosion, it cooled, and the particles coalesced into neutral hydrogen gas. Some patches were denser than others and, eventually, their gravity overcame the universe’s outward trajectory and the material collapsed inward, forming the first clumps of structure in the cosmos.

The density differences that allowed for structures both large and small to form in some places and not in others have been a longstanding topic of fascination. But until now, astronomers’ abilities to model how structure grew in the universe over the last 13 billion years faced mathematical limitations.

“The gravitational interactions occurring between all the particles in the universe are too complex to explain with simple mathematics,” Benson said.

So, astronomers either used mathematical approximations — which compromised the accuracy of their models — or large computer simulations that numerically model all the interactions between galaxies, but not all the interactions occurring between all of the particles, which was considered too complicated.

“A key goal of our survey was to count up the mass present in stars found in an enormous selection of distant galaxies and then use this information to formulate a new approach to understanding how structure formed in the universe,” Kelson explained.

The research team — which also included Carnegie’s Louis Abramson, Shannon Patel, Stephen Shectman, Alan Dressler, Patrick McCarthy, and John S. Mulchaey, as well as Rik Williams , now of Uber Technologies — demonstrated for the first time that the growth of individual proto-structures can be calculated and then averaged over all of space.

Doing this revealed that denser clumps grew faster, and less-dense clumps grew more slowly.

They were then able to work backward and determine the original distributions and growth rates of the fluctuations in density, which would eventually become the large-scale structures that determined the distributions of galaxies we see today.

In essence, their work provided a simple, yet accurate, description of why and how density fluctuations grow the way they do in the real universe, as well as in the computational-based work that underpins our understanding of the universe’s infancy.

“And it’s just so simple, with a real elegance to it,” added Kelson.

The findings would not have been possible without the allocation of an extraordinary number of observing nights at Las Campanas.

“Many institutions wouldn’t have had the capacity to take on a project of this scope on their own,” said Observatories Director John Mulchaey. “But thanks to our Magellan Telescopes, we were able to execute this survey and create this novel approach to answering a classic question.”

“While there’s no doubt that this project required the resources of an institution like Carnegie, our work also could not have happened without the tremendous number of additional infrared images that we were able to obtain at Kit Peak and Cerro Tololo, which are both part of the NSF’s National Optical-Infrared Astronomy Research Laboratory,” Kelson added.

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3D Printing Industry

3D Systems to release comprehensive list of test results for its latest Figure 4 materials

3D Systems is set to release the full set of results for its latest Figure 4 material tests. The tests conducted on the production-grade range were against both ASTM and ISO standards. The results will be published on March 23rd. The comprehensive list can be utilized by engineers and designers to rapidly decide on a material […]

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Author: Kubi Sertoglu

3D Printing Industry

Stratasys releases financial results for FY and Q4 2019, experiences weaknesses in Europe and Asia

3D printer OEM Stratasys (NASDAQ: SSYS) has published its financial accounts for the fourth quarter and full year ending December 31, 2019.  The company’s full year revenue was reported at $636.1 million, with a net loss of $11.1 million. Comparative figures for 2018 were $663.2 million and a loss of $11.2 million respectively. The revenue […]

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Author: Anas Essop


Apps could take up less space on your phone, thanks to new ‘streaming’ software

If you resort to deleting apps when your phone’s storage space is full, researchers have a solution.

New software “streams” data and code resources to an app from a cloud server when necessary, allowing the app to use only the space it needs on a phone at any given time.

“It’s like how Netflix movies aren’t actually stored on a computer. They are streamed to you as you are watching them,” said Saurabh Bagchi, a Purdue University professor of electrical and computer engineering, and computer science, and director of the Center for Resilient Infrastructures, Systems and Processes.

“Here the application components, like heavy video or graphics or code paths, are streaming instantly despite the errors and slowdowns that are possible on a cellular network.”

Bagchi’s team showed in a study how the software, called “AppStreamer,” cuts down storage requirements by at least 85% for popular gaming apps on an Android.

The software seamlessly shuffles data between an app and a cloud server without stalling the game. Most study participants didn’t notice any differences in their gaming experience while the app used AppStreamer.

Since AppStreamer works for these storage-hungry gaming apps, it could work for other apps that usually take up far less space, Bagchi said. The software also allows the app itself to download faster to a phone.

The researchers will present their findings Feb. 18 at the 17th International Conference on Embedded Wireless Systems and Networks in Lyon, France. Conference organizers have selected this study as one of three top papers.

AppStreamer is a type of software known as middleware, located between the apps on a device and the operating system.

The middleware automatically predicts when to fetch data from a cloud server. AT&T Labs Research provided data from cellular networks for this study to help evaluate which bandwidths AppStreamer would use and how much energy it would consume.

AppStreamer could help phones better accommodate 5G connectivity — high-speed wireless cellular networks that would allow devices to download movies in seconds and handle other data-heavy tasks much faster than the 4G networks currently available to most phones.

Using AppStreamer on a 5G network would mean that an app downloads instantly, runs faster and takes up minimal space on a phone.

The researchers also designed AppStreamer to use “edge computing,” which stores and sends data from edge servers. These servers, located in spots such as cellphone towers, are closer to a device compared to the cloud. The shorter distance reduces data download time.

Bagchi’s lab researches ways to make edge computing more reliable. Bagchi wrote on those challenges in an article recently published in Communications of the ACM.

The researchers believe that AppStreamer could be good for more than just phones. In order for self-driving cars to respond to their surroundings more safely, they would need to reliably pull data from servers in milliseconds. Middleware such as AppStreamer could eventually supply this functionality through edge computing on a 5G network.

This research was supported by AT&T and the National Science Foundation (grant numbers CNS-1409506 and CNS-1527262).

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Materials provided by Purdue University. Original written by Kayla Wiles. Note: Content may be edited for style and length.

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Researchers solve a scientific mystery about evaporation

Evaporation can explain why water levels drop in a full swimming pool, but it also plays an important role in industrial processes ranging from cooling electronics to power generation. Much of the global electricity supply is generated by steam plants, which are driven by evaporation.

But determining when and how quickly a liquid will convert to a vapor has been stymied by questions about how — and how much — the temperature changes at the point where the liquid meets the vapor, a concept known as temperature discontinuity. Those questions have made it more difficult to create more efficient processes using evaporation, but now researchers from the University of Houston have reported answers to what happens at that interface, addressing 20 years of conflicting findings. The work was reported in the Journal of Physical Chemistry.

The temperature discontinuity was first reported in 1999 by Canadian researchers G. Fang and C.A. Ward, who noted that they were unable to explain the phenomenon through classical mechanics. The new work solves that mystery.

Hadi Ghasemi, Cullen Associate Professor of Mechanical Engineering at UH, said the new understanding eliminates the “bottleneck” that has complicated predictions and simulations of processes involving evaporation.

“We demonstrated the physics of what happens within the space of a few molecules at the interface and accurately developed a theory on the evaporation rate,” Ghasemi said. “That allowed us to explain all of the conflicting findings that have been reported in the last 20 years and solve this mystery.”

In addition to Ghasemi, co-authors for the paper included first author Parham Jafari, a PhD student at UH, and Amit Amritkar, a research assistant professor at UH.

The researchers first approached the question in the lab, but Ghasemi said they were unable to get the needed spatial resolution for a definitive answer. They used a computational approach in order to find the properties of liquid and vapor within the length of a few molecules.

The explanation — developed using the Direct Simulation Monte Carlo method — will allow scientists to more accurate simulate the performance of all systems based on the theory of evaporation.

“With this understanding, we can more accurately develop simulations of performance and efficiency, as well as design and predict the behavior of advanced systems,” Ghasemi said.

That would have applications for energy, electronics, photonics and other fields.

As just one example of the importance of evaporation, Ghasemi noted that 80% of electric power globally is generated through steam plants, which work based on evaporation phenomena.

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IEEE Spectrum

CES 2020 Preview: A Haptic Phone Display, Scrunchable Battery, and Cooler That Makes Water From Air

CES 2020, which kicks off on Tuesday, will be full of Internet of Things (IoT) devices made smarter than ever by artificial intelligence, TVs and home appliances that beg you to converse with them, and wearables that tell you more about yourself than you likely want to know. 

But the best part of CES is the moment you spot a tiny treasure—that little gadget that is absolutely useful, and perfectly designed. Some tiny treasures are tucked into an array of gear from major manufacturers, and some are the sole products of new companies betting their bank accounts on a CES launch. There’s also joy—or at least entertainment value—in trying out a product that has automated something that really doesn’t need to be automated. 


Theoretical tubulanes inspire ultrahard polymers

A lightweight material full of holes is nearly as hard as diamond. The mere dents left by speeding bullets prove it.

Researchers at Rice University’s Brown School of Engineering and their colleagues are testing polymers based on tubulanes, theoretical structures of crosslinked carbon nanotubes predicted to have extraordinary strength.

The Rice lab of materials scientist Pulickel Ajayan found tubulanes can be mimicked as scaled-up, 3D-printed polymer blocks that prove to be better at deflecting projectiles than the same material without holes. The blocks are also highly compressible without breaking apart.

As detailed in Small, the discovery could lead to printed structures of any size with tunable mechanical properties.

Tubulanes were predicted in 1993 by chemist Ray Baughman of the University of Texas at Dallas and physicist Douglas Galvão of the State University of Campinas, Brazil, both co-principal investigators on the new paper. Tubulanes themselves have yet to be made, but their polymer cousins may be the next best thing.

Rice graduate student and lead author Seyed Mohammad Sajadi and his colleagues built computer simulations of various tubulane blocks, printed the designs as macroscale polymers and subjected them to crushing forces and speeding bullets. The best proved 10 times better at stopping a bullet than a solid block of the same material.

The Rice team fired projectiles into patterned and solid cubes at 5.8 kilometers per second. Sajadi said the results were impressive. “The bullet was stuck in the second layer of the structure,” he said. “But in the solid block, cracks propagated through the whole structure.”

Tests in a lab press showed how the porous polymer lattice lets tubulane blocks collapse in upon themselves without cracking, Sajadi said.

The Ajayan group made similar structures two years ago when it converted theoretical models of schwarzites into 3D-printed blocks. But the new work is a step toward what materials scientists consider a holy grail, Sajadi said.

“There are plenty of theoretical systems people cannot synthesize,” he said. “They’ve remained impractical and elusive. But with 3D printing, we can still take advantage of the predicted mechanical properties because they’re the result of the topology, not the size.”

Sajadi said tubulane-like structures of metal, ceramic and polymer are only limited by the size of the printer. Optimizing the lattice design could lead to better materials for civil, aerospace, automotive, sports, packaging and biomedical applications, he said.

“The unique properties of such structures comes from their complex topology, which is scale-independent,” said Rice alumnus Chandra Sekhar Tiwary, co-principal investigator on the project and now an assistant professor at the Indian Institute of Technology, Kharagpur. “Topology-controlled strengthening or improving load-bearing capability can be useful for other structural designs as well.”

According to co-authors Peter Boul and Carl Thaemlitz of Aramco Services Co., a sponsor of the research, potential applications span many industries, but oil and gas will find tubulane structures particularly valuable as tough and durable materials for well construction. Such materials must withstand impacts, particularly in hydraulic fracturing, that can rubblize standard cements.

“The impact resistance of these 3D-printed structures puts them in a class of their own,” Boul said.

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IEEE Spectrum

Ultrasonic Sensor Design with Cloud Engineering Simulation

This whitepaper explains how performing a full 3D simulation of an ultrasonic MEMS device circumvents the empirical approach to physical design.

What gives a 3-meter-long Amazonian fish some of the toughest scales on Earth

Arapaima gigas is a big fish in a bigger river full of piranhas, but that doesn’t mean it’s an easy meal. The freshwater giant has evolved armor-like scales that can deform, but do not tear or crack, when a piranha — which has one of the animal kingdom’s most powerful bites — attacks. Researchers from UC San Diego and UC Berkeley describe the unique properties of the Amazonian Arapaima skin and its potential for human-made materials October 16 in the journal Matter.

Arapaima‘s adaptation naturally solves a problem that engineers face when attempting to develop synthetic armors. Arapaima‘s scales have a tough, yet flexible, inner layer bound by collagen to its mineralized outer layer of scales. Similarly, bullet-proof vests are made of several layers of flexible webbing sandwiched between layers of hard plastic. But human-made materials are bound using a third adhesive material, whereas the fish’s scales are bound on an atomistic level; they grow together, weaving into one solid piece.

“A window may appear strong and solid, but it has no give. If something attempted to puncture it, the glass would shatter,” says senior author Robert Ritchie, a materials scientist at UC Berkeley. “When nature binds a hard material to a soft material, it grades it, preventing this shattering effect. And in this case, the binding structure is mineralized collagen.”

Other fish use collagen like Arapaima does, but the collagen layers in Arapaima scales are thicker than in any other fish species. The scales alone are each as thick as a grain of rice. Co-authors Yang, Quan, Meyers, and Ritchie hypothesize that this thickness is the secret to the fishes’ defense.

They tested this by soaking cracked Arapaima scales in water for 48 hours, then slowly pulling the edges apart while adding pressure to a central point. As they added pressure, they observed that the part of the mineralized, hard outer layer expanded, cracked, then gradually peeled off. The scales then localized the crack, containing it and preventing damage from spreading in the twisting structural collagen layer. If the pressure did break through to the collagen, it deformed the layer instead of breaking it.

If humans can develop a flexible hierarchical structure that behaves like the collagen layer in the fish scales, Ritchie says that better, potentially impermeable, synthetic armors can be made. But he also acknowledges that this reality may be a number of years down the line.

Until then, Ritchie’s team will investigate how Arapaima‘s scales have adapted to prevent penetration from piranha bites as well as how nature behaves this way in other species.

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Planes and vehicles main culprits masking iconic natural sounds in peaceful national parks

U.S. national parks are full of natural sounds. In Rocky Mountain National Park, visitors might hear the bugle of elks. At Yellowstone National Park, wolves howl in the distance. Iconic sounds like these are often associated with specific parks, creating unique soundscapes and enriching visitor experiences. When you add human-made noise to the mix, however, these sounds are at risk of being drowned out.

“Anthropogenic” noise — noise caused by human activity — has the unintended impact of masking natural sounds important to both visitors and wildlife. Noise is increasingly prevalent in natural spaces. Not only does this take away from visitors’ experiences, but it also has significant ecological consequences. Many animals’ survival depends on listening for approaching predators, and successful breeding for some species depends on listening for the song of a potential mate.

With these ecological consequences in mind, a team of scientists from Colorado State University (CSU) and the U.S. National Park Service (NPS) characterized the predominant human noise sources in 66 national parks in the U.S., in an effort to help parks better manage the noise problem. The study is published Oct. 2 in the Ecological Society of America’s journal Frontiers in Ecology and the Environment.

Human-made noise loud but localized in large parks

The researchers found that national park lands are largely bastions of natural sounds. While the team found anthropogenic noise causes a ten-fold or greater increase in natural background sound levels in over a third of parks in the study, the acreage impacted by such levels represents less than two percent of the total NPS lands.

This means that human-made noise is loud but localized within large parks, pointing to places where land managers can start to implement programs to manage noise. In small urban parks, which serve as places where city dwellers go to connect with nature, the natural space could be inundated with unwanted sounds.

The team found that even though trains and recreational watercraft are by far the loudest sources of noise, the greatest noise-causing culprits are vehicles and aircraft.

National Park Service lands remain among quietest areas in the U.S.

Rachel Buxton, lead author of the study, said the team was encouraged by how quiet, for the most part, national parks areas are. Wilderness areas and natural resource parks were found to have fewer noise events and are quieter than other park types across North America, such as cultural parks or recreation areas.

While NPS lands remain among the quietest protected areas in the U.S., noise made by people or machines is increasingly common and is heard in 37% of recordings collected from NPS lands across the country.

“When we visit a park to experience nature, hearing cars and planes can be annoying,” said Buxton, who conducted the research as a postdoctoral fellow in the Department of Fish, Wildlife and Conservation Biology in the Warner College of Natural Resources at CSU. “What many people don’t realize is that these noises disrupt the calming effect of being in nature, with significant effects on our wellbeing and the wellbeing of wildlife.” She is now a postdoctoral fellow at Carleton University in Ontario.

Research team analyzed nearly 47,000 hours of audio clips

The study relied on unprecedented audio data collection and analysis, the result of over a decade of collaboration between CSU and the NPS. Dozens of students at CSU — trained to identify and measure different types of sounds — processed 46,789 hours of audio clips from 251 sites in 66 parks.

The research team then identified how frequent noise events were, what type of noise is most commonly heard, and their respective noise levels, or how loud the noises are. The sounds were compared with measured noise levels across the continent, giving a more complete picture of where noise was highest and the most common sources.

Scientists found that it is more than just our vehicles making noise; another common source is simply human voices. In the context of visitor conversation, and speaking with and learning from park rangers, voices are intrinsic to park values and visitor experience. Yet, even when appropriate to the setting, these sounds affect wildlife. The designation of “quiet zones” can markedly improve noise levels, as successfully demonstrated in Muir Woods National Monument’s Cathedral Grove.

Research offers insight on better managing noise for park service leaders, staff

The U.S. National Park Service was established over a century ago to conserve natural and cultural resources for future generations, which includes the iconic sounds found in nature. “The Grand Canyon is grand because of its striking vistas, but also because of the sound of the river flowing through the canyon, wind rustling the leaves, and birds singing,” said Buxton. “Managing noise is essential for protecting our experiences in national parks, which are the country’s treasures.”

To fulfill this mission, NPS actively pursues innovations that will improve park sound environments and will showcase and improve sensory environments for people and ecosystems.

Researchers said the study findings can help parks understand the range of options available for managing noise from the most frequent noise culprits: cars and planes. To mitigate vehicle noise, parks can incorporate shuttle systems, establish speed limits, allow for electric vehicles, and use quiet pavement materials on roads. Aircraft noise, which can be heard from great distances at quiet sites, can be reduced by routing or scheduling flights to avoid sensitive areas.

“Numerous noise mitigation strategies have been successfully developed and implemented, so we already have the knowledge needed to address many of these issues,” said George Wittemyer, an associate professor at CSU and senior author of the study. “Our work provides information to facilitate such efforts in respect to protected areas where natural sounds are integral.”

The researchers said they are hopeful that as more noise research become public, people will consider sound as a valuable component of the natural environment, one that is currently at risk of being overwhelmed. “Protecting these important natural acoustic resources as development and land conversion progresses is critical if we want to preserve the character of parks,” Buxton added.

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