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  • richardmitnick 10:30 am on December 5, 2019 Permalink | Reply
    Tags: "Caltech Undergrads Build Robot for DARPA Challenge", Balto competed in the August 2019 tunnel-navigation section of the DARPA SubT Challenge., Balto is about half the size of the more powerful Huskies and costs an order of magnitude less., Balto-the robot truck, Caltech, , Like other teams CoSTAR has a diverse fleet of different types of robots including a hybrid rolling/flying robot; a tracked tank-like robot; and small flying drones that can navigate tunnels., Team CoSTAR, Truck-like robot will be a probe for exploring underground arenas.   

    From Caltech: “Caltech Undergrads Build Robot for DARPA Challenge” 

    Caltech Logo

    From Caltech

    December 02, 2019
    Robert Perkins
    (626) 395‑1862
    rperkins@caltech.edu

    Truck-like robot will be a probe for exploring underground arenas.

    1
    Caltech seniors Jake Ketchum and Alexandra (Sasha) Bodrova work on the superstructure that holds Balto’s critical custom components.

    A robot designed and built by undergraduate students at Caltech working with graduate students at Caltech and JPL, which Caltech manages for NASA, took to the field in the first phase of the Defense Advanced Research Projects Agency (DARPA) Subterranean (SubT) Challenge this summer, where the Caltech-JPL team took second place.

    The SubT Challenge is an international competition sponsored by DARPA to advance technologies to autonomously map, navigate, and search underground environments. Teams earn points by accurately identifying and mapping artifacts that represent items a first responder might find underground: items like a cell phone, backpack, or even a thermal manikin that simulates a survivor.

    The August competition, a tunnel-navigation task, was the first of three stages leading up to a final event in August 2021. In the second stage, to be held in Februrary 2020, the team will compete in an urban underground environment; in the third, in August 2020, they move to a cave. Teams that fail to perform well enough in any stage can be disqualified. For the final, the remaining teams will compete in an event that combines all three environments.

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    Balto competed in the August 2019 tunnel-navigation section of the DARPA SubT Challenge.

    In the tunnel competition, there were 11 teams, most made up of consortia of research institutions and private companies. Team CoSTAR (Collaborative SubTerranean Autonomous Resilient Robots), led by JPL Robotics Technologist Ali Agha, includes JPL, Caltech, MIT, the Korea Advanced Institute of Science and Technology (KAIST), and Sweden’s Lulea University of Technology.

    Like other teams, CoSTAR has a diverse fleet of different types of robots, including a hybrid rolling/flying robot, a tracked tank-like robot, and small flying drones that can navigate tunnels. The vehicles work together to perform assigned tasks: for example, a ground robot might begin exploration but come to an unnavigable roadblock, at which point a flying drone might be called in to explore beyond the roadblock. The backbone of the CoSTAR fleet is a group of simple, efficient, and reliable truck-like four-wheeled robots called the Huskies.

    The newest addition to the fleet, added this summer, looks like the runt of the Husky litter. Dubbed Balto after a famous rescue sled dog, the new robot was built atop a commercial radio control car. Caltech’s Joel Burdick, the Richard L. and Dorothy M. Hayman Professor of Mechanical Engineering and Bioengineering and JPL research scientist, and the leader of the Caltech section of the CoSTAR team, decided that using an off-the-shelf R/C as a base would fast track the development of Balto since the team was able to start with a vehicle that already had a sturdy suspension and powerful electric motor.

    Balto is about half the size of the more powerful Huskies, and costs an order of magnitude less. The final product is a vehicle that is about a meter long, weighs about 12 kilograms, and is capable of navigating slopes of up to 40 degrees. Because it is so light, it is also a good deal faster than the Huskies, and can reach speeds of 55 miles per hour.

    “The idea was to create a ground-based scout,” Burdick says. “The drones are our air-based scouts, and Balto is our eyes and ears on the ground. It’s light, cheap, and fast. It can get in, find out what’s going on, and help us to make decisions about how to proceed.” Balto can also fill in as a substitute in emergencies. For example, since wireless signals are often blocked in underground environments, SubT competitors have had to build ad hoc wireless networks by using robots stationed along the tunnel as wireless nodes so that the robots can communicate with one another. If one of the nodes fails, Balto is capable or quickly rushing in to fill in the gap.

    Initial work on Balto began in CS/EE/ME 75, Multidisciplinary Systems Engineering, a cross-discipline special projects undergraduate class at Caltech. This spring, a team of about a half-dozen undergraduate students began work on the off-the-shelf car that would become Balto. First, they stripped the body off of the vehicle’s chassis and began designing a removable superstructure that would house all of the equipment necessary to transform an R/C car into a self-guided robot explorer. The superstructure of Balto, which was built using milling machines and 3-D printers at Caltech, can be lifted as a single unit off of the chassis. Balto features a towering LIDAR unit (a detection and ranging technology in which the vehicle’s surroundings scanned with laser beams) that works in tandem with twin cameras to “see” its surroundings, a radio receiver that allows it to communicate with the rest of the fleet, and an on-board computer that contains the programming that makes the vehicle autonomous.

    “The chassis is largely stock, but Balto’s electrical and control systems have been entirely replaced,” says Jake Ketchum, now a Caltech senior, who led the CS/EE/ME 75 class team and continued to work on Balto through the Summer Undergraduate Research Fellowship (SURF) program.

    The team also swapped out the vehicle’s simple motor controller to an upgraded version that gives the autonomous guidance system more precise control over the vehicle’s speed, which allows them to more accurately place Balto where it is needed.

    “Balto was tested in the field and, in the fully autonomous mode, successfully navigated tunnels that were more than 100 meters long,” says Alexandra (Sasha) Bodrova, now a Caltech senior who also worked on Balto through the SURF program. “Balto detected and avoided obstacles such as rocks and rails, made sharp turns, and then returned to the starting line, in reverse.”

    4
    Alexandra Bodrova fabricates custom parts for Balto.

    At the beginning of the summer, the Balto team was expanded to include graduate student researchers Nikhilesh Alatur and Anushri Dixit, who were tasked with incorporating autonomous control to the vehicle and integrating it into CoSTAR’s fleet.

    Alatur and Dixit were among the CoSTAR team members who traveled to Pittsburgh for the first leg of the SubT Challenge, held at the National Institute for Occupational Safety and Health (NIOSH) Mining Program’s Safety Research Coal Mine and Experimental Mine, a federal site where mine-related safety and health research is conducted.

    The competition took place over the course of four days, with each team given one hour per day to complete specific tasks, most of which involved finding and engaging with objects of interest, like a backpack or a lever arm. While a small group of 10 engineers launched the robots at the mouth of the mine, most of the rest of the team, including Alatur and Dixit, watched the action via a livestream from the conference room near the mine.

    “Everyone worked in shifts, fixing robots during the night and watching the competition or sleeping during the day,” Dixit says.

    “Every day, up to 20 minutes before the start of our run, we weren’t even sure the team was going to get off of the line,” Burdick says, describing how the team would scramble to address software and hardware issues on its completely custom robots.

    Given the importance of the Huskies to the fleet, the first order of business was always to make sure they made it into the field. For the first three days of the competition, Balto mainly warmed the bench as the team deployed its other vehicles.

    Then, on the fourth and final day of competition, the decision was made to send in Balto.

    “It was pretty intense. There were five or six people gathered around the screen, and as soon as Balto went in, everyone started screaming and shouting and cheering,” says Alatur, graduate student at ETH Zurich who is spending a six-month stint on the CoSTAR team as a student researcher at JPL. “We were happy to see that Balto was sent in for the last few minutes of the competition and could make its debut in a DARPA challenge.” During the competition, Alatur and Dixit stayed in constant text contact with Ketchum and Bodrova, who watched the livesteam from Caltech and were equally excited to see the robot take to the field.

    Balto’s mission was limited; as Burdick puts it, the main goal was to see how the robot performed and to gather data that can be used to improve it for the next round of the competition. The original plan was that Balto would be tasked with positioning communication nodes—basically, wifi signal boosters that enable all of the robots in the tunnel to stay connected—but it turned out to be unnecessary. Instead, Balto drove 125 meters into the tunnel and stopped, just as directed, and acted as a wifi unit to relay signals as necessary. “In the end, we didn’t truly need it, but it did its job well,” Burdick says. “And more importantly, we gained data about Balto’s performance that will help us down the line.”

    Because of Balto’s speed, diminutive size, and ruggedness, Burdick predicts a growing role for the little robot in future competitions. This year’s CS/EE/ME 75 class will continue to refine Balto, as well as other new vehicles to be used in the next phases of the competition in February and August, 2020.

    “I think we’re going to be grateful to have a small, tough robots like Balto when we get to the final event in 2021,” he says.

    See the full article here .


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    Please help promote STEM in your local schools.


    Stem Education Coalition

    The California Institute of Technology (commonly referred to as Caltech) is a private research university located in Pasadena, California, United States. Caltech has six academic divisions with strong emphases on science and engineering. Its 124-acre (50 ha) primary campus is located approximately 11 mi (18 km) northeast of downtown Los Angeles. “The mission of the California Institute of Technology is to expand human knowledge and benefit society through research integrated with education. We investigate the most challenging, fundamental problems in science and technology in a singularly collegial, interdisciplinary atmosphere, while educating outstanding students to become creative members of society.”

    Caltech campus

     
  • richardmitnick 11:06 am on November 21, 2019 Permalink | Reply
    Tags: "Caltech and the City of Pasadena Team Up to Build Seismic Sensing Network", A citywide fiber optic earthquake detector capable of mapping how temblors are shaking the city at millimeter-scale resolution., Caltech   

    From Caltech: “Caltech and the City of Pasadena Team Up to Build Seismic Sensing Network” 

    Caltech Logo

    From Caltech

    1

    November 19, 2019
    Robert Perkins
    (626) 395‑1862
    rperkins@caltech.edu

    Caltech and the City of Pasadena are teaming up to create a citywide fiber optic earthquake detector capable of mapping how temblors are shaking the city at millimeter-scale resolution.

    The work will take advantage of two currently unused—or “dark”—strands of Pasadena’s fiber optic cable that stretch in a large loop around the city. Using a couple strands of fiber to measure seismic activity will gather data equivalent to more than 30,000 seismometers, while only 11 traditional seismometers exist within the city limits today. Zhongwen Zhan, assistant professor of geophysics, will tap into the fiber network at the Seeley G. Mudd Building of Geophysics and Planetary Science on Caltech’s campus on California Boulevard.

    2

    There, Zhan will station two laser emitters that shoot beams of light through the cables. The cables have tiny imperfections every few meters that reflect back a minuscule portion of the light to the source, where it is tracked and recorded. In this manner, each imperfection acts as a trackable waypoint along the fiber optic cable, which is typically buried just below ground level. Seismic waves moving through the ground cause the cable to expand and contract slightly, which changes the travel time of light to and from these waypoints. Thus, the imperfections act like individual seismometers that allow seismologists to observe the motion of seismic waves.

    “Engineers try to minimize the imperfections in the cable because it adds noise when transmitting information from one point to another. For us, however, the imperfections are the point. They turn the cable into a big chain of virtual seismometers,” Zhan says.

    The laser light launched into the fiber is emitted by distributed acoustic sensing (DAS) interrogators, devices designed for use in oil exploration. One, designed in the lab of Miguel Gonzalez-Herraez of the University of Alcalá in Spain and constructed by manufacturer Aragon Photonics, will track a 37-kilometer section of cable clockwise from Caltech’s campus. The other, borrowed from manufacturer OptaSense, was deployed to monitor a section of fiber along the 395 Freeway, tracking aftershocks from this summer’s Ridgecrest earthquake sequence. It recently returned to Pasadena to take a more detailed look at a 10-kilometer section along the same cable path, but counter-clock-wise from the Caltech campus.

    The unbroken loop of cable allows for light to be shot in both directions through the cable, generating a clearer signal. Ultimately, the DAS devices should capture 20 terabytes of data every month. Because of the high resolution of data that the fiber can capture, the network could one day provide city officials real-time information during an earthquake about how severe the shaking is throughout the city on a block-by-block basis.

    The city maintains a network of fiber optic cable running beneath Pasadena for municipal operations and commercial services, not all of which is currently in use. City officials granted access to that dark fiber to Zhan under a five-year agreement.

    “The City of Pasadena’s fiber optics paired with Caltech’s research will produce a tremendous amount of data that will help our efforts to prepare, educate, and communicate the impacts of earthquakes in our community,” says Phillip Leclair, chief information officer for the City of Pasadena. “Measuring seismic activity with fiber will give officials impact and damage predictions by neighborhood—a huge benefit for public safety and disaster recovery.”

    Zhan hopes that this project can serve as a model for other cities and seismologists, with municipalities throughout Southern California taking advantage of their fiber optic networks for seismic monitoring.

    “These fiber optic networks already exist in many municipalities, creating the opportunity for this project to expand throughout the region and perhaps even beyond,” Zhan says.

    “The Pasadena project is an important step forward in lighting up dark fiber throughout Southern California and achieving our vision of a seismic monitoring system equivalent to having a million seismometers placed throughout the region,” says Mike Gurnis, director of Caltech’s Seismological Laboratory and John E. and Hazel S. Smits Professor of Geophysics. “This will be a leap forward in our ability to monitor the subsurface in much greater detail. We are particularly grateful for the support shown by the City of Pasadena. This advancement would never have happened without them.”

    The work is made possible by a National Science Foundation CAREER Award, funding from Caltech trustee Li Lu, and a partnership with the City of Pasadena, and Caltech’s Division of Geological and Planetary Sciences.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings
    Please help promote STEM in your local schools.


    Stem Education Coalition

    The California Institute of Technology (commonly referred to as Caltech) is a private research university located in Pasadena, California, United States. Caltech has six academic divisions with strong emphases on science and engineering. Its 124-acre (50 ha) primary campus is located approximately 11 mi (18 km) northeast of downtown Los Angeles. “The mission of the California Institute of Technology is to expand human knowledge and benefit society through research integrated with education. We investigate the most challenging, fundamental problems in science and technology in a singularly collegial, interdisciplinary atmosphere, while educating outstanding students to become creative members of society.”

    Caltech campus

     
  • richardmitnick 3:23 pm on November 13, 2019 Permalink | Reply
    Tags: , Caltech, , IEQNET-Illinois Express Quantum Network,   

    From Fermi National Accelerator Lab: “DOE awards Fermilab and partners $3.2 million for Illinois quantum network” 

    FNAL Art Image
    FNAL Art Image by Angela Gonzales

    From Fermi National Accelerator Lab , an enduring source of strength for the US contribution to scientific research world wide.

    November 13, 2019
    edited by Leah Hesla

    1
    The proposed Illinois Express Quantum Network is a metropolitan-scale, quantum-classical hybrid design combining quantum technologies with existing classical networks to create a multinode system for multiple users.

    The Department of Energy has announced that it will grant Fermilab and partner institutions $3.2 million to develop designs for transparent optical quantum networks and demonstrate their operation in the greater Chicago area.

    The proposed Illinois-Express Quantum Network, or IEQNET, connects nodes at Fermilab and proposed nodes at Northwestern University’s Chicago and Evanston campuses. The metropolitan-scale network uses a combination of cutting-edge quantum and classical technologies to transmit quantum information and will be designed to coexist with classical networks.

    “Our team brings together researchers who are leading the way in quantum communications, classical networking, quantum devices and fast-timing electronics,” said scientist Panagiotis Spentzouris, head of quantum science at Fermilab and the project’s principal investigator. “That marriage of world-class expertise enables us to develop the new network.”

    Fermilab is the lead institution for the IEQNET collaboration, which includes the Department of Energy’s Argonne National Laboratory, Caltech and Northwestern University.

    “We have leading quantum technology capabilities at our respective institutions,” said Northwestern University’s Prem Kumar, one of the researchers on the project. “Now we’re combining them to create new opportunities for distributed quantum communications.”

    Scientists have previously demonstrated point-to-point quantum communications over short distances — on the order of 10 miles — in fiber-optic cables. IEQNET’s goal is to demonstrate a multinode fiber-optic quantum network that supports multiple users.

    “We will be using state-of-the-art sources and photodetectors in nodes we have built already at Fermilab to co-distribute classical and quantum information across Chicagoland,” said Caltech scientist Maria Spiropulu, another IEQNET researcher. “We want to identify and address the challenges toward nontrivial, long-distance multilayered architectures that support multiple end-users and test various protocols.”

    IEQNET’s objective supports the United States in meeting the goals of its National Quantum Initiative, a coordinated multiagency program to support research and training in quantum information science. It also positions Chicago as one of the few places in the nation advancing quantum communications. The proposed network stretches between the Chicago area institutions using existing fiber-optic cables.

    “We want to utilize existing links because we have significant infrastructure that has already been laid for classical communications,” said Rajkumar Kettimuthu, an Argonne scientist affiliated with IEQNET. “One of the challenges will be to achieve classical and quantum co-existence in the same fibers.”

    IEQNET leverages existing conventional infrastructure and experience from ESnet, a high-speed computer network serving DOE scientists and their collaborators worldwide. ESnet is managed by Lawrence Berkeley National Laboratory, also a DOE national laboratory.

    The project also brings together small quantum tech industry partners, including businesses such as NuCrypt and HyperLight, and the Intelligent Quantum Networks and Technologies, or INQNET, program, which was developed through a Caltech and AT&T partnership and is a member of the Quantum Economic Development Consortium of the National Institute of Standards and Technology.

    By connecting business with academia, IEQNET has the potential to generate new technologies that have wider application in industry, helping elevate the Chicago area as a hot spot for technology transfer in quantum science.

    IEQNET is one of the recently announced five four-year projects aimed at developing wide-area quantum networks funded by the DOE Office of Science.

    “We are on the threshold of a new era in quantum information science and quantum computing and networking, with potentially great promise for science and society,” said DOE Under Secretary for Science Paul Dabbar in an announcement from DOE. “These projects will help ensure U.S. leadership in these important new areas of science and technology.”

    See the full here.


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    Please help promote STEM in your local schools.

    Stem Education Coalition

    FNAL Icon

    Fermi National Accelerator Laboratory (Fermilab), located just outside Batavia, Illinois, near Chicago, is a US Department of Energy national laboratory specializing in high-energy particle physics. Fermilab is America’s premier laboratory for particle physics and accelerator research, funded by the U.S. Department of Energy. Thousands of scientists from universities and laboratories around the world
    collaborate at Fermilab on experiments at the frontiers of discovery.

     
  • richardmitnick 1:00 pm on November 7, 2019 Permalink | Reply
    Tags: "Unlocking Turbulence", , Caltech,   

    From Caltech: “Unlocking Turbulence” 

    Caltech Logo

    From Caltech

    November 05, 2019
    Robert Perkins
    (626) 395‑1862
    rperkins@caltech.edu

    Caltech engineer exploits the repeating structure of turbulence to create a more complete model of the phenomenon.

    A Caltech engineer has unlocked some of the secrets behind turbulence, a much-studied but difficult-to-pin-down phenomenon that mixes fluids when they flow past a solid boundary.

    Beverly McKeon, the Theodore von Kármán Professor of Aeronautics in the Division of Engineering and Applied Science, studies fluid mechanics.

    1
    Beverly McKeon

    She specializes in turbulent flows, or technically speaking those with high Reynolds numbers. These types of flows are often seen in pipes and around aircraft and are of keen interest, for example, to aerospace engineers.

    1
    Turbulence. McKeon Research Group at Caltech.

    At the boundary where a fluid flows over a fixed structure, a turbulent boundary layer is created where the fluid interacts with the wall, creating eddies in the current. These eddies may seem to be random on first glance, but they actually create distinct patterns, with countless tiny eddies close to the wall; fewer but larger eddies located a little farther out; and even fewer, but still larger, eddies beyond those. These eddies have a significant impact on the fluid flow, helping to determine features such as its pressure, velocity, and density, which are important to understand when engineering an aircraft or industrial piping, for example.

    In the 1950s and ’60s, mathematician Alan Townsend of Cambridge University proposed that a lot of the important statistical properties of a turbulent flow could be described based on this concept of eddies as persistent, organized flow patterns that are, in essence, “attached” to a wall—even without a clear understanding of what those eddies actually are. Through the ’80s and ’90s, researchers led by Tony Perry, Ivan Marusic, and their colleagues at Australia’s University of Melbourne built on Townsend’s hypothesis to develop the “attached eddy” model of wall turbulence, which has proven to be effective at describing the statistical behavior of the common phenomenon.

    As an analogy, think of weather prediction. If you compiled 100 years’ worth of weather reports, you could derive the average weather for an area and make a reasonable prediction about what the weather will be tomorrow. That is a statistical model. If you instead studied each of the physical systems that affect the weather—the ocean, the clouds, the topography—you could create a model that predicts the weather based on the various inputs to that system. That is a dynamical model.

    A statistical model is easier to process, but a dynamical model is not a slave to the past; because it attempts to describe and understand what drives the system overall, it is capable of predicting future changes in the system that might be outside of the average norms. And like the weather, turbulence is a dynamic and ever-changing phenomenon.

    The problem, however, is that simulating something as complex as turbulence using the equations of motion is an incredibly complex, computationally challenging task, McKeon says. Imagine trying to disassemble an entire car with just a monkey wrench. You might eventually get the job done, but it will take a lot of time and energy.

    McKeon found a way to bridge the empirical and mathematical models by creating an equations-derived description of turbulence that exploits the fact that turbulence creates predictably repeating structures. The shape and structure of the eddies in turbulence are geometrically self-similar, meaning that each of the eddies are identical, just on different scales, similar to a fractal pattern.

    Mathematically quantifying these repetitions, McKeon was able to formulate a dynamical model that describes turbulence using a sort of shorthand, allowing it to extrapolate how the overall system will look based on a zoomed-in look at just a few eddies. Because it describes an incredibly large-scale and complex system by boiling it down to a simple, repeating component, McKeon’s model can generate mathematically useful models of turbulent systems using dramatically less compute power than was previously required.

    “We knew that, underlying these very complicated structures, there had to be a very simple pattern. We just didn’t know what that pattern was until now,” says McKeon, who next plans to dig deeper into the model to quantify just how many eddies should be included to create an accurate representation of the whole.

    The model could prove useful to engineers across industry who are looking to more easily simulate turbulent systems. But more importantly, it represents fundamental research that will help scientists and engineers better understand what drives those turbulent systems.

    McKeon’s study is titled “Self-similar hierarchies and attached eddies” and was published by Physical Review Fluids on August 26. Her work was funded by the Office of Naval Research.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings
    Please help promote STEM in your local schools.


    Stem Education Coalition

    The California Institute of Technology (commonly referred to as Caltech) is a private research university located in Pasadena, California, United States. Caltech has six academic divisions with strong emphases on science and engineering. Its 124-acre (50 ha) primary campus is located approximately 11 mi (18 km) northeast of downtown Los Angeles. “The mission of the California Institute of Technology is to expand human knowledge and benefit society through research integrated with education. We investigate the most challenging, fundamental problems in science and technology in a singularly collegial, interdisciplinary atmosphere, while educating outstanding students to become creative members of society.”

    Caltech campus

     
  • richardmitnick 2:05 pm on October 23, 2019 Permalink | Reply
    Tags: "Earthquakes in Slow Motion", , Caltech, , So-called "slow slip" or "silent" earthquakes   

    From Caltech: “Earthquakes in Slow Motion” 

    Caltech Logo

    From Caltech

    October 23, 2019
    Robert Perkins
    (626) 395‑1862
    rperkins@caltech.edu

    Studying “slow-slip” events could shed light on destructive temblors.

    1

    A new study from Caltech finds that so-called “slow slip” or “silent” earthquakes behave more like regular earthquakes than previously thought. The discovery opens the door for geoscientists to use these frequent and nondestructive events as an easy-to-study analog that will help them find out what makes earthquakes tick.


    GPS stations reveal activity beneath Cascadia where the oceanic floor slides beneath North America. The plate interface is locked at shallow depths (the shaded area), but we see recurring slow-slip events (in blue) that unzip the plate interface, generating tremors (the black dots).

    Slow-slip events were first noted about two decades ago by geoscientists tracking otherwise imperceptible shifts in the earth using GPS technology. They occur when faults grind incredibly slowly against each other, like an earthquake in slow motion. For example, a slow-slip event that occurs over the course of weeks might release the same amount of energy as a minute-long magnitude-7.0 earthquake. Because they occur deep in the earth and release energy so slowly, there is very little deformation at the surface, although the slow events might affect an area of thousands of square kilometers. As such, they were only noted when GPS technology was refined to the point that it could track those very minute shifts. Slow-slip events also do not occur along every fault; so far, they have been spotted in just a handful of locations including the Pacific Northwest, Japan, Mexico, and New Zealand.

    As they have only just begun to be detected and cataloged, a lot remains unknown about them, says Jean-Philippe Avouac, Caltech’s Earle C. Anthony Professor of Geology and Mechanical and Civil Engineering. “There’s a lot of uncertainty. You can’t study them using traditional seismological techniques because the signal they create is too faint and gets lost in the noise from human activities as well as from natural geological processes like ocean waves, rivers, and winds.” Before Avouac’s group began this study, there were not enough documented slow-slip events to determine their scaling properties reliably, he says.

    Avouac’s group designed and applied an innovative signal processing technique to detect and image the slow-slip events along Washington state’s Cascadia Subduction Zone, where the North American tectonic plate is sliding southwest over the Pacific Ocean plate, using a network of 352 GPS stations. The researchers analyzed data spanning the years 2007 to 2018 and were able to build a catalog of more than 40 slow-slip events of varied sizes. Their findings appear in Nature on October 23.

    Compiling data from these events, the researchers were able to characterize the features of slow-slip events more precisely than previously possible. One key finding from the study is that slow-slip events obey the same scaling laws as regular earthquakes.

    In this context, the scaling law describes the “moment” of a slip event on a fault—which quantifies the elastic energy released by slip on a fault—as a function of the duration of slip. In practical terms, that means that a big slip across a broad area yields a long-lasting earthquake. It has long been known that the moment of an earthquake is proportional to the cube of the amount of time the earthquake lasts. In 2007, a team from the University of Tokyo and Stanford suggested that slow-slip events appear to be different, with the moment seemingly directly proportional to time.

    Armed with their new fleshed-out catalog, Avouac’s team argues that the magnitudes of slow-slip events also are proportional to the cube of their duration, just like regular earthquakes.

    Since these events behave similarly to regular earthquakes, studying them could shed light on their more destructive cousins, Avouac says, particularly because slow-slip events occur more frequently. While a traditional magnitude-7.0 earthquake might only occur along a fault every couple of hundred years, a slow-slip event of that magnitude can reoccur along the same fault every year or two.

    “If we study a fault for a dozen years, we might see 10 of these events,” Avouac says. “That lets us test models of the seismic cycle, learning how different segments of a fault interact with one another. It gives us a clearer picture of how energy builds up and is released with time along a major fault.” Such information could offer more insight into earthquake mechanics and the physics governing their timing and magnitude, he says.

    Avouac’s co-authors are Sylvain Michel of the École normale supérieure in Paris and Caltech visiting researcher Adriano Gualandi. Their work was funded by the National Science Foundation and the French National Centre for Space Studies.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings
    Please help promote STEM in your local schools.


    Stem Education Coalition

    The California Institute of Technology (commonly referred to as Caltech) is a private research university located in Pasadena, California, United States. Caltech has six academic divisions with strong emphases on science and engineering. Its 124-acre (50 ha) primary campus is located approximately 11 mi (18 km) northeast of downtown Los Angeles. “The mission of the California Institute of Technology is to expand human knowledge and benefit society through research integrated with education. We investigate the most challenging, fundamental problems in science and technology in a singularly collegial, interdisciplinary atmosphere, while educating outstanding students to become creative members of society.”

    Caltech campus

     
  • richardmitnick 3:48 pm on October 17, 2019 Permalink | Reply
    Tags: A dense network of seismometers observed the seismic waves that radiated from the earthquake., Caltech, Magnitude 6.4 foreshock on July 4 2019, Magnitude 7.1 mainshock July 5 2019, NASA Find Web of Ruptures in Ridgequest Quake", , Ridgecrest Earthquake Sequence, Satellites observed the surface ruptures and associated ground deformation extending out over 60 miles (100 kilometers) in every direction from the rupture., Southern California's largest earthquake sequence in two decades, The complexity of the event is only clear because of the multiple types of scientific instruments used to study it., The event illustrates how little we still understand about earthquakes., The Ridgecrest ruptures ended just a few miles shy of the Garlock Fault a major east-west fault running more than 185 miles (300 kilometers) from the San Andreas Fault to Death Valley., The Ridgecrest sequence involved about 20 previously undiscovered smaller faults crisscrossing in a geometrically complex and geologically young fault zone.   

    From NASA JPL-Caltech: “Caltech, NASA Find Web of Ruptures in Ridgequest Quake” 

    NASA JPL Banner

    From NASA JPL-Caltech

    October 17, 2019

    Esprit Smith
    Jet Propulsion Laboratory, Pasadena, Calif.
    818-354-4269
    esprit.smith@jpl.nasa.gov

    Robert Perkins
    Caltech, Pasadena, Calif.
    626-395-1862
    rperkins@caltech.edu

    1
    A USGS Earthquake Science Center Mobile Laser Scanning truck scans the surface rupture near the zone of maximum surface displacement of the magnitude 7.1 earthquake that struck the Ridgecrest area. Credit: USGS / Ben Brooks

    A new study of Southern California’s largest earthquake sequence in two decades provides new evidence that large earthquakes can occur in a more complex fashion than commonly assumed. The analysis by geophysicists from Caltech and NASA’s Jet Propulsion Laboratory, both in Pasadena, California, documents a series of ruptures in a web of interconnected faults, with rupturing faults triggering other faults.

    The dominoes-like sequence of ruptures also increased strain on a nearby major fault, according to the study, which was published today in the journal Science.

    The Ridgecrest Earthquake Sequence began with a magnitude 6.4 foreshock on July 4, 2019, followed by a magnitude 7.1 mainshock the next day with more than 100,000 aftershocks. The sequence rattled most of Southern California, but the strongest shaking occurred about 120 miles (190 kilometers) north of Los Angeles near the town of Ridgecrest.

    “This ended up being one of the best-documented earthquake sequences in history,” said Zachary Ross, assistant professor of geophysics at Caltech and lead author of the Science paper. Ross developed an automated computer analysis of seismometer data that detected the enormous number of aftershocks with highly precise location information, and the JPL team members analyzed data from international radar satellites ALOS-2 (from the Japan Aerospace Exploration Agency, or JAXA) and Sentinel-1A/B (operated by the European Space Agency, or ESA) to map fault ruptures at Earth’s surface.

    JAXA ALOS-2 satellite aka DAICH-2

    ESA Sentinel-1B

    “I was surprised to see how much complexity there was and the number of faults that ruptured,” said JPL co-author Eric Fielding.

    The satellite and seismometer data together depict an earthquake sequence that is far more complex than those found in the models of many previous large seismic events. Major earthquakes are commonly thought to be caused by the rupture of a single long fault, such as the more than 800-mile-long (1,300-kilometer-long) San Andreas fault, with the maximum possible magnitude dictated primarily by the length of the fault. After a large 1992 earthquake in Landers, California, ruptured several faults, seismologists began rethinking that model.

    The Ridgecrest sequence involved about 20 previously undiscovered, smaller faults crisscrossing in a geometrically complex and geologically young fault zone.

    “We actually see that the magnitude 6.4 quake simultaneously broke faults at right angles to each other, which is surprising because standard models of rock friction view this as unlikely,” Ross said.

    2
    All earthquakes of magnitude 2.5 and greater in the Ridgecrest area July 4 to Aug. 15, 2019, are shown as gray circles. Red stars mark the two largest. The Garlock Fault south of the cluster of earthquakes has slipped almost an inch since July. Credit: USGS

    The complexity of the event is only clear because of the multiple types of scientific instruments used to study it. Satellites observed the surface ruptures and associated ground deformation extending out over 60 miles (100 kilometers) in every direction from the rupture, while a dense network of seismometers observed the seismic waves that radiated from the earthquake. Together, these data allowed scientists to develop a model of how the faults slipped below the surface and the relationship between the major slipping faults and the significant number of small earthquakes occurring before, between and after the two largest shocks.

    The Ridgecrest ruptures ended just a few miles shy of the Garlock Fault, a major east-west fault running more than 185 miles (300 kilometers) from the San Andreas Fault to Death Valley. The fault has been relatively quiet for the past 500 years, but the strain placed on the Garlock Fault by July’s earthquake activity triggered it to start slowly moving, a process call fault creep. The fault has slipped 0.8 inches (2 centimeters) at the surface since July, the scientists said.

    The event illustrates how little we still understand about earthquakes. “It’s going to force people to think hard about how we quantify seismic hazard and whether our approach to defining faults needs to change,” Ross said. “We can’t just assume that the largest faults dominate the seismic hazard if many smaller faults can link up to create these major quakes.”

    See the full article here .


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    Please help promote STEM in your local schools.

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    NASA JPL Campus

    Jet Propulsion Laboratory (JPL)) is a federally funded research and development center and NASA field center located in the San Gabriel Valley area of Los Angeles County, California, United States. Although the facility has a Pasadena postal address, it is actually headquartered in the city of La Cañada Flintridge, on the northwest border of Pasadena. JPL is managed by the nearby California Institute of Technology (Caltech) for the National Aeronautics and Space Administration. The Laboratory’s primary function is the construction and operation of robotic planetary spacecraft, though it also conducts Earth-orbit and astronomy missions. It is also responsible for operating NASA’s Deep Space Network.

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  • richardmitnick 9:53 am on October 17, 2019 Permalink | Reply
    Tags: As baffling as the concept of two entangled particles may be the situation becomes even more complex when more particles are involved., At Caltech researchers are focusing their studies on many-body entangled systems., Caltech, Entanglement Passes Tests with Flying Colors, In 1935 Albert Einstein Boris Podolsky and Nathan Rosen published a paper on the theoretical concept of quantum entanglement which Einstein called “spooky action at a distance.”, , , The perplexing phenomenon of quantum entanglement is central to quantum computing; quantum networking; and the fabric of space and time., The phenomenon of entanglement was first proposed by Albert Einstein and colleagues in the 1930s.   

    From Caltech: “Untangling Quantum Entanglement” 

    Caltech Logo

    From Caltech

    Caltech Magazine Fall 2019
    Whitney Clavin

    1
    In Erwin Schrödinger’s famous thought experiment, a cat is trapped in a box with a bit of poison the release of which is controlled by a quantum process. The cat therefore exists in a quantum state of being both dead and alive until somebody opens the box and finds the cat either dead or alive.

    The perplexing phenomenon of quantum entanglement is central to quantum computing, quantum networking, and the fabric of space and time.

    The famous “Jim twins,” separated soon after birth in the 1940s, seemed to live parallel lives even though they grew up miles apart in completely different families. When they were reunited at the age of 39, they discovered many similarities between their life stories, including the names of their sons, wives, and childhood pets, as well as their preferences for Chevrolet cars, carpentry, and more.

    A similar kind of parallelism happens at a quantum level, too. The electrons, photons, and other particles that make up our universe can become inextricably linked, such that the state observed in one particle will be identical for the other. That connection, known as entanglement, remains strong even across vast distances.

    “When particles are entangled, it’s as if they are born that way, like twins,” says Xie Chen, associate professor of theoretical physics at Caltech. “Even though they might be separated right after birth, [they’ll] still look the same. And they grow up having a lot of personality traits that are similar to each other.”

    The phenomenon of entanglement was first proposed by Albert Einstein and colleagues in the 1930s. At that time, many questioned the validity of entanglement, including Einstein himself. Over the years and in various experiments, however, researchers have generated entangled particles that have supported the theory. In these experiments, researchers first entangle two particles and then send them to different locations miles apart. The researchers then measure the state of one particle: for instance, the polarization (or direction of vibration) of a photon. If that entangled photon displays a horizontal polarization, then so too will its faithful partner.

    “It may be tempting to think that the particles are somehow communicating with each other across these great distances, but that is not the case,” says Thomas Vidick, a professor of computing and mathematical sciences at Caltech. “There can be correlation without communication.” Instead, he explains, entangled particles are so closely connected that there is no need for communication; they “can be thought of as one object.”

    As baffling as the concept of two entangled particles may be, the situation becomes even more complex when more particles are involved. In natural settings such as the human body, for example, not two but hundreds of molecules or even more become entangled, as they also do in various metals and magnets, making up an interwoven community. In these many-body entangled systems, the whole is greater than the sum of its parts.

    “The particles act together like a single object whose identity lies not with the individual components but in a higher plane. It becomes something larger than itself,” says Spyridon (Spiros) Michalakis, outreach manager of Caltech’s Institute for Quantum Information and Matter (IQIM) and a staff researcher. “Entanglement is like a thread that goes through every single one of the individual particles, telling them how to be connected to one another.”

    2
    Associate Professor of Theoretical Physics Xie Chen specializes in the fields of condensed matter physics and quantum information.

    At Caltech, researchers are focusing their studies on many-body entangled systems, which they believe are critical to the development of future technologies and perhaps to cracking fundamental physics mysteries. Scientists around the world have made significant progress applying the principles of many-body entanglement to fields such as quantum computing, quantum cryptography, and quantum networks (collectively known as quantum information); condensed-matter physics; chemistry; and fundamental physics. Although the most practical applications, such as quantum computers, may still be decades off, according to John Preskill, the Richard P. Feynman Professor of Theoretical Physics at Caltech and the Allen V.C. Davis and Lenabelle Davis Leadership Chair of the Institute of Quantum Science and Technology (IQST), “entanglement is a very important part of Caltech’s future.”

    Entanglement Passes Tests with Flying Colors

    In 1935, Albert Einstein, Boris Podolsky, and Nathan Rosen published a paper on the theoretical concept of quantum entanglement, which Einstein called “spooky action at a distance.” The physicists described the idea, then argued that it posed a problem for quantum mechanics, rendering the theory incomplete. Einstein did not believe two particles could remain connected to each other over great distances; doing so, he said, would require them to communicate faster than the speed of light, something he had previously shown to be impossible.

    Today, experimental work leaves no doubt that entanglement is real. Physicists have demonstrated its peculiar effects across hundreds of kilometers; in fact, in 2017, a Chinese satellite named Micius sent entangled photons to three different ground stations, each separated by more than 1,200 kilometers, and broke the distance record for entangled particles.

    Entanglement goes hand in hand with another quantum phenomenon known as superposition, in which particles exist in two different states simultaneously. Photons, for example, can display simultaneously both horizontal and vertical states of polarization.

    Or, to simplify, consider two “entangled” quarters, each hidden under a cup. If two people, Bob and Alice, were each to take one of those quarters to a different room, the quarters would remain both heads and tails until one person lifted the cup and observed his or her quarter; at that point, it would randomly become either heads or tails. If Alice were to lift her cup first and her quarter was tails, then when Bob observed his quarter, it would also be tails. If you repeated the experiment and the coins are covered once more, they would go back to being in a state of superposition. Alice would lift her cup again and might find her quarter as heads this time. Bob would then also find his quarter as heads. Whether the first quarter is found to be heads or tails is entirely random.

    Similarly, when a researcher entangles two photons and then sends each one in different directions under carefully controlled conditions, they will continue to be in a state of superposition, both horizontally and vertically polarized. Only when one of the photons is measured do both randomly adopt just one of the two possible polarization states.

    “Quantum correlations are deeply different than ordinary correlations,” says Preskill. “And randomness is the key. This spooky intrinsic randomness is actually what bothered Einstein. But it is essential to how the quantum world works.”

    “Scientists often use the word correlation to explain what is happening between these particles,” adds Oskar Painter, the John G Braun Professor of Applied Physics and Physics at Caltech. “But, actually, entanglement is the perfect word.”

    Entanglement to the Nth Degree

    Untangling the relationship between two entangled particles may be difficult, but the real challenge is to understand how hundreds of particles, if not more, can be similarly interconnected.

    According to Manuel Endres, an assistant professor of physics at Caltech, one of the first steps toward understanding many-body entanglement is to create and control it in the lab. To do this, Endres and his team use a brute force approach: they design and build laboratory experiments with the goal of creating a system of 100 entangled atoms.

    “This is fundamentally extremely difficult to do,” says Endres. In fact, he notes, it would be difficult even at a much smaller scale. “If I create a system where I generate, for instance, 20 entangled particles, and I send 10 one way and 10 another way, then I have to measure whether each one of those first 10 particles is entangled with each of the other set of 10. There are many different ways of looking at the correlations.”

    While the task of describing those correlations is difficult, describing a system of 100 entangled atoms with classical computer bits would be unimaginably hard. For instance, a complete classical description of all the quantum correlations among as many as 300 entangled particles would require more bits than the number of atoms in the visible universe. “But that’s the whole point and the reason we are doing this,” Endres says. “Things get so entangled that you need a huge amount of space to describe the information. It’s a complicated beast, but it’s useful.”

    “Generally, the number of parameters you need to describe the system is going to scale up exponentially,” says Vidick, who is working on mathematical and computational tools to describe entanglement. “It blows up very quickly, which, in general, is why it’s hard to make predictions or simulations, because you can’t even represent these systems in your laptop’s memory.”

    To solve that problem, Vidick and his group are working on coming up with computational representations of entangled materials that are simpler and more succinct than models that currently exist.

    “Quantum mechanics and the ideas behind quantum computing are forcing us to think outside the box,” he says.

    A Fragile Ecosystem

    Another factor in creating and controlling quantum systems has to do with their delicate nature. Like Mimosa pudica ,a member of the pea family also known as the “sensitive plant,” which droops when its leaves are touched, entangled states can easily disappear, or collapse, when the environment changes even slightly. For example, the act of observing a quantum state destroys it. “You don’t want to even look at your experiment, or breathe on it,” jokes Painter. Adds Preskill, “Don’t turn on the light, and don’t even dare walk into the room.”

    The problem is that entangled particles become entangled with the environment around them quickly, in a matter of microseconds or faster. This then destroys the original entangled state a researcher might attempt to study or use. Even one stray photon flying through an experiment can render the whole thing useless.

    “You need to be able to create a system that is entangled only with itself, not with your apparatus,” says Endres. “We want the particles to talk to one another in a controlled fashion. But we don’t want them to talk to anything in the outside world.”

    In the field of quantum computing, this fragility is problematic because it can lead to computational errors. Quantum computers hold the promise of solving problems that classical computers cannot, including those in cryptography, chemistry, financial modeling, and more. Where classical computers use binary bits (either a “1” or a “0”) to carry information, quantum computers use “qubits,” which exist in states of “1” and “0” at the same time. As Preskill explains, the qubits in this mixed state, or superposition, would be both dead and alive, a reference to the famous thought experiment proposed by Erwin Schrödinger in 1935, in which a cat in a box is both dead and alive until the box is opened, and the cat is observed to be one or the other. What’s more, those qubits are all entangled. If the qubits somehow become disentangled from one another, the quantum computer would be unable to execute its computations.

    To address these issues, Preskill and Alexei Kitaev (Caltech’s Ronald and Maxine Linde Professor of Theoretical Physics and Mathematics and recipient of a 2012 Breakthrough Prize in Fundamental Physics), along with other theorists at Caltech, have devised a concept to hide the quantum information within a global entangled state, such that none of the individual bits have the answer. This approach is akin to distributing a code among hundreds of people living in different cities. No one person would have the whole code, so the code would be much less vulnerable to discovery.

    4
    Manuel Endres, assistant professor of physics, here pictured with Adam Shaw (left) and Ivaylo Madjarov (right), uses laser-based techniques in his lab to create many-body entanglement.

    “The key to correcting errors in entangled systems is, in fact, entanglement,” says Preskill. “If you want to protect information from damage due to the extreme instability of superpositions, you have to hide the information in a form that’s very hard to get at,” he says. “And the way you do that is by encoding it in a highly entangled state.”

    Spreading the Entanglement

    At Caltech, this work on the development of quantum-computing systems is conducted alongside with research into quantum networks in which each quantum computer acts as a separate node, or connection point, for the whole system. Painter refers to this as “breaking a quantum computer into little chunks” and then connecting them together to create a distributed network. In this approach, the chunks would behave as if they were not separated. “The network would be an example of many-body entanglement, in which the bodies are the different nodes in the network,” says Painter.

    Quantum networks would enhance the power of quantum computers, notes Preskill.

    “We’d like to build bigger and bigger quantum computers to solve harder and harder problems. And it’s hard to build one piece of hardware that can handle a million qubits,” he says. “It’s easier to make modular components with 100 qubits each or something like that. But then, if you want to solve harder problems, you’ve got to get these different little quantum computers to communicate with one another. And that would be done through a quantum network.”

    Quantum networks could also be used for cryptography purposes, to make it safer to send sensitive information; they would also be a means by which to distribute and share quantum information in the same way that the World Wide Web works for conventional computers. Another future use might be in astronomy. Today’s telescopes are limited. They cannot yet see any detail on, for instance, the surface of distant exoplanets, where astronomers might want to look for signs of life or civilization. If scientists could combine telescopes into a quantum network, it “would allow us to use the whole Earth as one big telescope with a much-improved resolution,” says Preskill.

    “Up until about 20 years ago, the best way to explore entanglement was to look at what nature gave us and try to study the exotic states that emerged,” notes Painter. “Now our goal is to try to synthesize these systems and go beyond what nature has given us.”

    At the Root of Everything

    While entanglement is the key to advances in quantum-information sciences, it is also a concept of interest to theoretical physicists, some of whom believe that space and time itself are the result of an underlying network of quantum connections.

    “It is quite incredible that any two points in space-time, no matter how far apart, are actually entangled. Points in space-time that we consider closer to each other are just more entangled than those further apart,” says Michalkis.

    The link between entanglement and space-time may even help solve one of the biggest challenges in physics: establishing a unifying theory to connect the macroscopic laws of general relativity (which describe gravity) with the microscopic laws of quantum physics (which describe how subatomic particles behave).

    The quantum error-correcting schemes that Preskill and others study may play a role in this quest. With quantum computers, error correction ensures that the computers are sufficiently robust and stable. Something similar may occur with space-time. “The robustness of space may come from a geometry where you can perturb the system, but it isn’t affected much by the noise, which is the same thing that happens in stable quantum-computing schemes,” says Preskill.

    “Essentially, entanglement holds space together. It’s the glue that makes the different pieces of space hook up with one another,” he adds.

    At Caltech, the concept of entanglement connects various labs and buildings across campus. Theorists and experimentalists in computer science, quantum-information science, condensed-matter physics, and other fields regularly work across disciplines and weave together their ideas.

    “We bring our ideas from condensed-matter physics to quantum-information folks, and we say, ‘Hey, I have a material you can use for quantum computation,’” says Chen. “Sometimes we borrow ideas from them. Many of us from different fields have realized that we have to deal with entanglement head-on.”

    Preskill echoes this sentiment and is convinced entanglement is an essential part of Caltech’s future: “We are making investments and betting on entanglement as being one of the most important themes of 21st-century science.”

    See the full article here .


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    Please help promote STEM in your local schools.


    Stem Education Coalition

    The California Institute of Technology (commonly referred to as Caltech) is a private research university located in Pasadena, California, United States. Caltech has six academic divisions with strong emphases on science and engineering. Its 124-acre (50 ha) primary campus is located approximately 11 mi (18 km) northeast of downtown Los Angeles. “The mission of the California Institute of Technology is to expand human knowledge and benefit society through research integrated with education. We investigate the most challenging, fundamental problems in science and technology in a singularly collegial, interdisciplinary atmosphere, while educating outstanding students to become creative members of society.”

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  • richardmitnick 1:37 pm on October 4, 2019 Permalink | Reply
    Tags: , , , Caltech, , , KAGRA joins the hunt,   

    From Caltech: “KAGRA to Join LIGO and Virgo in Hunt for Gravitational Waves” 

    Caltech Logo

    From Caltech

    October 04, 2019
    Whitney Clavin
    wclavin@caltech.edu

    KAGRA gravitational wave detector, Kamioka mine in Kamioka-cho, Hida-city, Gifu-prefecture, Japan

    Japan’s Kamioka Gravitational-wave Detector (KAGRA) will soon team up with the National Science Foundation’s Laser Interferometer Gravitational-wave Observatory (LIGO) and Europe’s Virgo in the search for subtle shakings of space and time known as gravitational waves. Representatives for the three observatories signed a memorandum of agreement (MOA) about their collaborative efforts today, October 4. The agreement includes plans for joint observations and data sharing.

    “This is a great example of international scientific cooperation,” says Caltech’s David Reitze, executive director of the LIGO Laboratory. “Having KAGRA join our network of gravitational-wave observatories will significantly enhance the science in the coming decade.”

    “At present, KAGRA is in the commissioning phase, after the completion of its detector construction this spring. We are looking forward to joining the network of gravitational-wave observations later this year,” says Takaaki Kajita, principal investigator of the KAGRA project and co-winner of the 2015 Nobel Prize in Physics.

    In 2015, the twin detectors of LIGO, one in Washington and the other in Louisiana, made history by making the first direct detection of gravitational waves, a discovery that earned three of the project’s founders—Caltech’s Barry Barish, Ronald and Maxine Linde Professor of Physics, Emeritus, and Kip Thorne, Richard P. Feynman Professor of Theoretical Physics, Emeritus; and MIT’s Rainer Weiss, professor of physics, emeritus—the 2017 Nobel Prize in Physics. Since then, LIGO and its partner Virgo have identified more than 30 likely detections of gravitational waves, mostly from colliding black holes.

    “The more detectors we have in the global gravitational-wave network, the more accurately we can localize the gravitational-wave signals on the sky, and the better we can determine the underlying nature of cataclysmic events that produced the signals.” says Reitze.

    For instance, in 2017, Virgo and the two LIGO detectors were able together to localize a merger of two neutron stars to a patch of sky about 30 square degrees in size, or less than 0.1 percent of the sky. This was a small enough patch to enable ground-based and space telescopes to pinpoint the galaxy that hosted the collision and observe its explosive aftermath in light.

    “These findings amounted to the first time a cosmic event had been observed in both gravitational waves and light and gave astronomers a first-of-its kind look at the spectacular smashup of neutron stars,” says Virgo Collaboration spokesperson Jo van den Brand of Nikhef (the Dutch National Institute for Subatomic Physics) and Maastricht University in the Netherlands.

    With KAGRA joining the network, these gravitational-wave events will eventually be narrowed down to patches of sky that are only about 10 square degrees, greatly enhancing the ability of light-based telescopes to carry out follow-up observations. For its initial run, KAGRA will operate at sensitivities that are likely too low to detect gravitational waves, but with time, as the performance of the instrumentation is improved, it will reach sensitivities high enough to join the hunt.

    Having a fourth detector will also increase the overall detection rate, helping scientists to probe and understand some of the most energetic events in the universe.

    KAGRA is expected to come online for the first time in December of this year, joining the third observing run of LIGO and Virgo, which began on April 1, 2019.

    MIT /Caltech Advanced aLigo


    VIRGO Gravitational Wave interferometer, near Pisa, Italy

    The Japanese detector will pioneer two new approaches to gravitational-wave searches. It will be the first kilometer-scale gravitational-wave observatory to operate underground, which will dampen unwanted noise from winds and seismic activity; and it will be the first to use cryogenically chilled mirrors, a technique that cuts down on thermal noise.

    “These features could supply a very important direction for the futureof gravitational-wave detectors with much higher sensitivities. Therefore, we should make every effort, for the global gravitational-wave community, to prove that the underground site and the cryogenic mirrors are useful,” says Kajita.

    The new MOA also includes the German-British GEO600 detector. Although GEO600 is not sensitive enough to detect gravitational-wave signals from distant black hole and neutron star collisions, it has been important for testing new technologies that will be key for improving future detectors. In addition, LIGO India is expected to join the network of observatories in 2025, signifying the beginning of a truly global effort to catch ripples in the fabric of space and time.

    Additional information about the gravitational-wave observatories:

    LIGO is funded by NSF and operated by Caltech and MIT, which conceived of LIGO and lead the project. Financial support for the Advanced LIGO project was led by the NSF with Germany (Max Planck Society), the U.K. (Science and Technology Facilities Council) and Australia (Australian Research Council-OzGrav) making significant commitments and contributions to the project. Approximately 1,300 scientists from around the world participate in the effort through the LIGO Scientific Collaboration, which includes the GEO Collaboration. A list of additional partners is available at https://my.ligo.org/census.php.

    The Virgo Collaboration is currently composed of approximately 480 scientists, engineers, and technicians from about 96 institutes from Belgium, France, Germany, Hungary, Italy, the Netherlands, Poland, and Spain. The European Gravitational Observatory (EGO) hosts the Virgo detector near Pisa in Italy, and is funded by Centre National de la Recherche Scientifique (CNRS) in France, the Istituto Nazionale di Fisica Nucleare (INFN) in Italy, and Nikhef in the Netherlands. A list of the Virgo Collaboration members can be found at http://public.virgo-gw.eu/the-virgo-collaboration/. More information is available on the Virgo website at http://www.virgo-gw.eu.

    The KAGRA project is supported by MEXT (Ministry of Education, Culture, Sports, Science, and Technology-Japan). KAGRA is hosted by the Institute for Cosmic Ray Research (ICRR), the University of Tokyo, and co-hosted by High Energy Accelerator Research Organization (KEK) and the National Astronomical Observatory of Japan (NAOJ). The KAGRA collaboration is composed of more than 360 individuals from more than 100 institutions from 15 countries/regions. The list of collaborators’ affiliations is available at http://gwwiki.icrr.u-tokyo.ac.jp/JGWwiki/KAGRA/KSC#KAGRAcollaborators. More information is available on the KAGRA website at https://gwcenter.icrr.u-tokyo.ac.jp/en/.

    See the full article here .


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    Please help promote STEM in your local schools.


    Stem Education Coalition

    The California Institute of Technology (commonly referred to as Caltech) is a private research university located in Pasadena, California, United States. Caltech has six academic divisions with strong emphases on science and engineering. Its 124-acre (50 ha) primary campus is located approximately 11 mi (18 km) northeast of downtown Los Angeles. “The mission of the California Institute of Technology is to expand human knowledge and benefit society through research integrated with education. We investigate the most challenging, fundamental problems in science and technology in a singularly collegial, interdisciplinary atmosphere, while educating outstanding students to become creative members of society.”

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  • richardmitnick 11:21 am on September 12, 2019 Permalink | Reply
    Tags: , Architected metamaterials, Caltech, , , ,   

    From Caltech: “New Metamaterial Morphs Into New Shapes, Taking on New Properties” 

    Caltech Logo

    From Caltech

    September 11, 2019

    Robert Perkins
    (626) 395‑1862
    rperkins@caltech.edu

    1

    A newly developed type of architected metamaterial has the ability to change shape in a tunable fashion.

    While most reconfigurable materials can toggle between two distinct states, the way a switch toggles on or off, the new material’s shape can be finely tuned, adjusting its physical properties as desired. The material, which has potential applications in next-generation energy storage and bio-implantable micro-devices, was developed by a joint Caltech-Georgia Tech-ETH Zürich team in the lab of Julia R. Greer.

    Greer, the Ruben F. and Donna Mettler Professor of Materials Science, Mechanics and Medical Engineering in Caltech’s Division of Engineering and Applied Science, creates materials out of micro- and nanoscale building blocks that are arranged into sophisticated architectures that can be periodic, like a lattice, or non-periodic in a tailor-made fashion, giving them unusual physical properties.

    Most materials that are designed to change shape require a persistent external stimulus to change from one shape to another and stay that way: for example, they may be one shape when wet and a different shape when dry—like a sponge that swells as it absorbs water.

    By contrast, the new nanomaterial deforms through an electrochemically driven silicon-lithium alloying reaction, meaning that it can be finely controlled to attain any “in-between” states, remain in these configurations even upon the removal of the stimulus, and be easily reversed. Apply a little current, and a resulting chemical reaction changes the shape by a controlled, small degree. Apply a lot of current, and the shape changes substantially. Remove the electrical control, and the configuration is retained—just like tying off a balloon. A description of the new type of material was published online by the journal Nature on September 11.

    Defects and imperfections exist in all materials, and can often determine a material’s properties. In this case, the team chose to take advantage of that fact and build in defects to imbue the material with the properties they wanted.

    “The most intriguing part of this work to me is the critical role of defects in such dynamically responsive architected materials,” says Xiaoxing Xia, a graduate student at Caltech and lead author of the Nature paper.

    For the Nature paper, the team designed a silicon-coated lattice with microscale straight beams that bend into curves under electrochemical stimulation, taking on unique mechanical and vibrational properties. Greer’s team created these materials using an ultra-high-resolution 3D printing process called two-photon lithography. Using this novel fabrication method, they were able to build in defects in the architected material system, based on a pre-arranged design. In a test of the system, the team fabricated a sheet of the material that, under electrical control, reveals a Caltech icon.

    3

    “This just further shows that materials are just like people, it’s the imperfections that make them interesting. I have always had a particular liking for defects, and this time Xiaoxing managed to first uncover the effect of different types of defects on these metamaterials and then use them to program a particular pattern that would emerge in response to electrochemical stimulus,” says Greer.

    A material with such a finely controllable ability to change shape has potential in future energy storage systems because it provides a pathway to create adaptive energy storage systems that would enable batteries, for example, to be significantly lighter, safer, and to have substantially longer lives, Greer says. Some battery materials expand when storing energy, creating a mechanical degradation due to stress from the repeated expanding and contracting. Architected materials like this one can be designed to handle such structural transformations.

    “Electrochemically active metamaterials provide a novel pathway for development of next generation smart batteries with both increased capacity and novel functionalities. At Georgia Tech, we are developing the computational tools to predict this complex coupled electro-chemo-mechanical behavior,” says Claudio V. Di Leo, assistant professor of aerospace engineering at the Georgia Institute of Technology.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings
    Please help promote STEM in your local schools.


    Stem Education Coalition

    The California Institute of Technology (commonly referred to as Caltech) is a private research university located in Pasadena, California, United States. Caltech has six academic divisions with strong emphases on science and engineering. Its 124-acre (50 ha) primary campus is located approximately 11 mi (18 km) northeast of downtown Los Angeles. “The mission of the California Institute of Technology is to expand human knowledge and benefit society through research integrated with education. We investigate the most challenging, fundamental problems in science and technology in a singularly collegial, interdisciplinary atmosphere, while educating outstanding students to become creative members of society.”

    Caltech campus

     
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