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  • richardmitnick 9:47 am on April 24, 2017 Permalink | Reply
    Tags: , Lithium batteries, phys.org   

    From Columbia via phys.org: “Freezing lithium batteries may make them safer and bendable” 

    Columbia U bloc

    Columbia University

    phys.org

    [THIS IS IMPORTANT AS WE SEE GREATER USE OF LITHIUM BATTERIES]

    April 24, 2017

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    Schematic of vertically aligned and connected ceramic channels for enhancing ionic conduction. In the left figure, ceramic particles are randomly dispersed in the polymer matrix, where ion transport is blocked by the polymer matrix with a low conductivity. In the right one, vertically aligned and connected structure facilitates ion transport, which can be realized by the ice-templating method. Credit: Yuan Yang/Columbia Engineering.

    Yuan Yang, assistant professor of materials science and engineering at Columbia Engineering, has developed a new method that could lead to lithium batteries that are safer, have longer battery life, and are bendable, providing new possibilities such as flexible smartphones. His new technique uses ice-templating to control the structure of the solid electrolyte for lithium batteries that are used in portable electronics, electric vehicles, and grid-level energy storage. The study is published online April 24 in Nano Letters.

    Liquid electrolyte is currently used in commercial lithium batteries, and, as everyone is now aware, it is highly flammable, causing safety issues with some laptops and other electronic devices. Yang’s team explored the idea of using solid electrolyte as a substitute for the liquid electrolyte to make all-solid-state lithium batteries. They were interested in using ice-templating to fabricate vertically aligned structures of ceramic solid electrolytes, which provide fast lithium ion pathways and are highly conductive. They cooled the aqueous solution with ceramic particles from the bottom and then let ice grow and push away and concentrate the ceramic particles. They then applied a vacuum to transition the solid ice to a gas, leaving a vertically aligned structure. Finally, they combined this ceramic structure with polymer to provide mechanical support and flexibility to the electrolyte.

    “In portable electronic devices, as well as electric vehicles, flexible all-solid-state lithium batteries not only solve the safety issues, but they may also increase battery energy density for transportation and storage. And they show great promise in creating bendable devices,” says Yang, whose research group is focused on electrochemical energy storage and conversion and thermal energy management.

    Researchers in earlier studies used either randomly dispersed ceramic particles in polymer electrolyte or fiber-like ceramic electrolytes that are not vertically aligned. “We thought that if we combined the vertically aligned structure of the ceramic electrolyte with the polymer electrolyte, we would be able to provide a fast highway for lithium ions and thus enhance the conductivity,” says Haowei Zhai, Yang’s PhD student and the paper’s lead author. “We believe this is the first time anyone has used the ice-templating method to make flexible solid electrolyte, which is nonflammable and nontoxic, in lithium batteries. This opens a new approach to optimize ion conduction for next-generation rechargeable batteries.”

    In addition, the researchers say, this technique could in principle improve the energy density of batteries: By using the solid electrolyte, the lithium battery’s negative electrode, currently a graphite layer, could be replaced by lithium metal, and this could improve the battery’s specific energy by 60% to 70%. Yang and Zhai plan next to work on optimizing the qualities of the combined electrolyte and assembling the flexible solid electrolyte together with battery electrodes to construct a prototype of a full lithium battery.

    “This is a clever idea,” says Hailiang Wang, assistant professor of chemistry at Yale University. “The rationally designed structure really helps enhance the performance of composite electrolyte. I think that this is a promising approach.”

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    See the full article here .

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    Columbia U Campus

    Columbia University was founded in 1754 as King’s College by royal charter of King George II of England. It is the oldest institution of higher learning in the state of New York and the fifth oldest in the United States.

     
  • richardmitnick 12:10 pm on April 20, 2017 Permalink | Reply
    Tags: , Oceans galore: new study suggests most habitable planets may lack dry land, phys.org   

    From phys.org: “Oceans galore: new study suggests most habitable planets may lack dry land” 

    physdotorg
    phys.org

    April 20, 2017
    Dr Robert Massey

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    Continents on other habitable worlds may struggle to break above sea level, like much of Europe in this illustration, representing Earth with an estimated 80% ocean coverage. Credit: Antartis / Depositphotos.com

    When it comes to exploring exoplanets, it may be wise to take a snorkel along. A new study, published in a paper in the journal Monthly Notices of the Royal Astronomical Society, has used a statistical model to predict that most habitable planets may be dominated by oceans spanning over 90% of their surface area.

    The author of the study, Dr Fergus Simpson of the Institute of Cosmos Sciences at the University of Barcelona, has constructed a statistical model – based on Bayesian probability – to predict the division between land and water on habitable exoplanets.

    For a planetary surface to boast extensive areas of both land and water, a delicate balance must be struck between the volume of water it retains over time, and how much space it has to store it in its oceanic basins. Both of these quantities may vary substantially across the full spectrum of water-bearing worlds, and why the Earth’s values are so well balanced is an unresolved and long-standing conundrum.

    Simpson’s model predicts that most habitable planets are dominated by oceans spanning over 90% of their surface area. This conclusion is reached because the Earth itself is very close to being a so-called ‘waterworld’ – a world where all land is immersed under a single ocean.

    “A scenario in which the Earth holds less water than most other habitable planets would be consistent with results from simulations, and could help explain why some planets have been found to be a bit less dense than we expected,” explains Simpson.

    In the new work, Simpson finds that the Earth’s finely balanced oceans may be a consequence of the anthropic principle – more often used in a cosmological context – which accounts for how our observations of the Universe are influenced by the requirement for the formation of sentient life.

    “Based on the Earth’s ocean coverage of 71%, we find substantial evidence supporting the hypothesis that anthropic selection effects are at work,” comments Simpson.

    To test the statistical model Simpson has taken feedback mechanisms into account, such as the deep water cycle, and erosion and deposition processes. He also proposes a statistical approximation to determine the diminishing habitable land area for planets with smaller oceans, as they become increasingly dominated by deserts.

    Why did we evolve on this planet and not on one of the billions of other habitable worlds? In this study Simpson suggests the answer could be linked to a selection effect involving the balance between land and water.

    “Our understanding of the development of life may be far from complete, but it is not so dire that we must adhere to the conventional approximation that all habitable planets have an equal chance of hosting intelligent life,” Simpson concludes.

    See the full article here .

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    About Phys.org in 100 Words

    Phys.org™ (formerly Physorg.com) is a leading web-based science, research and technology news service which covers a full range of topics. These include physics, earth science, medicine, nanotechnology, electronics, space, biology, chemistry, computer sciences, engineering, mathematics and other sciences and technologies. Launched in 2004, Phys.org’s readership has grown steadily to include 1.75 million scientists, researchers, and engineers every month. Phys.org publishes approximately 100 quality articles every day, offering some of the most comprehensive coverage of sci-tech developments world-wide. Quancast 2009 includes Phys.org in its list of the Global Top 2,000 Websites. Phys.org community members enjoy access to many personalized features such as social networking, a personal home page set-up, RSS/XML feeds, article comments and ranking, the ability to save favorite articles, a daily newsletter, and other options.

     
  • richardmitnick 11:20 am on April 19, 2017 Permalink | Reply
    Tags: , , , , OSU - Ohio State University, phys.org, , Tidal disruption event (TDE) known as iPTF16fnl   

    From Ohio State via phys.org: “Ultraviolet spectroscopic evolution of a tidal disruption event investigated by astronomers” 

    OSU

    Ohio State University

    phys.org

    April 19, 2017
    Tomasz Nowakowski

    1
    The UV evolution of iPTF16fnl as revealed by HST/STIS spectra and Swift photometry.
    The spectra have been smoothed with a 5 pixel boxcar and scaled by a constant factor to best match the Swift photometry for ease of comparison. The dashed lines show our blackbody fits to the host subtracted Swift fluxes. Prominent atomic transitions are marked with vertical dotted lines. The thin gray line shows our estimate of the UV spectrum of the host based on the SED model. Credit: Brown et al., 2017.

    NASA/ESA Hubble Telescope

    NASA/SWIFT Telescope

    An international team of astronomers led by Jonathan S. Brown of the Ohio State University in Columbus, Ohio, has studied the ultraviolet spectroscopic evolution of a nearby low-luminosity tidal disruption event (TDE) known as iPTF16fnl. The results of this study, published Apr. 7 on arXiv.org., offer new clues on the nature of this TDE.

    TDE occurs when a star passes close enough to a supermassive black hole and is pulled apart by the black hole’s tidal forces, causing the process of disruption. Such tidally disrupted stellar debris then rains down on the black hole and radiation emerges from the innermost region of accreting debris, which indicates the presence of a TDE.

    TDEs serve as invaluable probes of strong gravity and accretion physics, providing answers about the formation and evolution of supermassive black holes. While most such events are discovered in optical transient surveys, ultraviolet observations provide an opportunity to learn much more about the kinematics and ionization structure of tidally disrupted stellar debris.

    iPTF16fnl was discovered on Aug. 26, 2016 as a transient consistent with the center of the galaxy Mrk 0950. This transient was later classified as a rapidly evolving, low-luminosity TDE, located about 220 million light years away. It is the nearest TDE found so far and its black hole mass is estimated to be not greater than 5.5 million solar masses.

    Due to the proximity of iPTF16fnl to Earth, Brown and his colleagues decided to initiate a follow-up observational campaign in order to study this event in detail. These observations were conducted using the Hubble Space Telescope’s (HST) Space Telescope Imaging Spectrograph (STIS) and the Ultraviolet/Optical Telescope (UVOT) onboard NASA’s Swift spacecraft. The researchers also employed several ground-based observatories in order to perform photometric and spectroscopic monitoring of this event. All these instruments allowed the team to spectroscopically observe the temporal evolution of a TDE in ultraviolet light for the first time ever.

    “We presented for the first time the UV spectroscopic evolution of a TDE using data from HST/STIS,” Brown’s team wrote in a research paper available on arXiv.org.

    The results show that shape and velocity offset of the broad ultraviolet emission in iPTF16fnl and absorption features evolve with time.

    “There is significant evolution in the shape and central wavelength of the line profiles over the course of our observations, such that at early times, the lines are broad and redshifted, while at later times, the lines are significantly narrower and peak near the wavelengths of their corresponding atomic transitions,” the paper reads.

    The researchers found that ultraviolet spectra of iPTF16fnl closely resemble those of ASASSN-14li (other nearby TDE) and nitrogen-rich quasars. When it comes to optical spectra of iPTF16fnl, the findings indicate that they resemble those of several other optically discovered TDEs.

    “The dominant emission features closely resemble those seen in the UV spectra of the TDE ASASSN-14li and are also similar to those of N-rich quasars,” the authors wrote.

    All the data obtained by various space and ground-based telescopes allowed the scientists to draw conclusion that iPTF16fnl is subluminous and evolves more rapidly than other optically detected TDEs.

    See the full article here .

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  • richardmitnick 11:11 am on April 6, 2017 Permalink | Reply
    Tags: , Atmosphere around super-Earth detected, , , phys.org   

    From phys.org: “Atmosphere around super-Earth detected” 

    physdotorg
    phys.org

    April 6, 2017

    1
    Credit: Max Planck Society

    Astronomers have detected an atmosphere around the super-Earth GJ 1132b. This marks the first detection of an atmosphere around a low-mass super-Earth, in terms of radius and mass the most Earth-like planet around which an atmosphere has yet been detected. Thus, this is a significant step on the path towards the detection of life on an exoplanet. The team, which includes researchers from the Max Planck Institute for Astronomy, used the 2.2-m ESO/MPG telescope in Chile to take images of the planet’s host star, GJ 1132, and measured the slight decrease in brightness as the planet and its atmosphere absorbed some of the starlight while passing directly in front of their host star.

    MPG/ESO 2.2 meter telescope at Cerro La Silla, Chile, 600 km north of Santiago de Chile at an altitude of 2400 metres

    While it’s not the detection of life on another planet, it’s an important step in the right direction: the detection of an atmosphere around the super-Earth GJ 1132b marks the first time an atmosphere has been detected around a planet with a mass and radius close to Earth’s mass and radius (1.6 Earth masses, 1.4 Earth radii).

    Astronomers’ current strategy for finding life on another planet is to detect the chemical composition of that planet’s atmosphere, on the lookout for certain chemical imbalances that require the presence of living organisms as an explanation. In the case of our own Earth, the presence of large amounts of oxygen is such a trace.

    We’re still a long way from that detection though. Until the work described in this article, the (few!) observations of light from exoplanet atmospheres all involved planets much more massive than Earth: gas giants—relatives of our own solar system’s Jupiter—and a large super-Earth with more than eight times the Earth’s mass. With the present observation, we’ve taken the first tentative steps into analyzing the atmosphere of smaller, lower-mass planets that are much more Earth-like in size and mass.

    The planet in question, GJ 1132b, orbits the red dwarf star GJ 1132 in the southern constellation Vela, at a distance of 39 light-years from us. Recently, the system has come under scrutiny by a team led by John Southworth (Keele University, UK). The project was conceived, and the observations coordinated, by Luigi Mancini, formerly of the Max Planck Institute for Astronomy (MPIA) and now working at the University of Rome Tor Vergata. Additional MPIA team members were Paul Mollière and Thomas Henning.

    The team used the GROND imager at the 2.2-m ESO/MPG telescope of the European Southern Observatory in Chile to observe the planet simultaneously in seven different wavelength bands.

    ESO GROND imager on 2.2 meter MPG/ESO telescope at LaSilla

    GJ 1132b is a transiting planet: From the perspective of an observer on Earth, it passes directly in front of its star every 1.6 days, blocking some of the star’s light.

    The size of stars like GJ 1132 is well known from stellar models. From the fraction of starlight blocked by the planet, astronomers can deduce the planet’s size—in this case around 1.4 times the size of the Earth. Crucially, the new observations showed the planet to be larger at one of the infrared wavelengths than at the others. This suggests the presence of an atmosphere that is opaque to this specific infrared light (making the planet appear larger) but transparent at all the others. Different possible versions of the atmosphere were then simulated by team members at the University of Cambridge and the Max Planck Institute for Astronomy. According to those models, an atmosphere rich in water and methane would explain the observations very well.

    The discovery comes with the usual exoplanet caveats: while somewhat larger than Earth, and with 1.6 times Earth’s mass (as determined by earlier measurements), observations to date do not provide sufficient data to decide how similar or dissimilar GJ 1132b is to Earth. Possibilities include a “water world” with an atmosphere of hot steam.

    The presence of the atmosphere is a reason for cautious optimism. M dwarfs are the most common types of star, and show high levels of activity; for some set-ups, this activity (in the shape of flares and particle streams) can be expected to blow away nearby planets’ atmospheres. GJ 1132b provides a hopeful counterexample of an atmosphere that has endured for billion of years (that is, long enough for us to detect it). Given the great number of M dwarf stars, such atmospheres could mean that the preconditions for life are quite common in the universe.

    In any case, the new observations make GJ 1132b a high-priority target for further study by instruments such as the Hubble Space Telescope, ESO’s Very Large Telescope, and the James Webb Space Telescope slated for launch in 2018.

    The work described here has been published as J. Southworth et al., Detection of the atmosphere of the 1.6 Earth mass exoplanet GJ 1132B in the Astronomical Journal.

    See the full article here .

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    About Phys.org in 100 Words

    Phys.org™ (formerly Physorg.com) is a leading web-based science, research and technology news service which covers a full range of topics. These include physics, earth science, medicine, nanotechnology, electronics, space, biology, chemistry, computer sciences, engineering, mathematics and other sciences and technologies. Launched in 2004, Phys.org’s readership has grown steadily to include 1.75 million scientists, researchers, and engineers every month. Phys.org publishes approximately 100 quality articles every day, offering some of the most comprehensive coverage of sci-tech developments world-wide. Quancast 2009 includes Phys.org in its list of the Global Top 2,000 Websites. Phys.org community members enjoy access to many personalized features such as social networking, a personal home page set-up, RSS/XML feeds, article comments and ranking, the ability to save favorite articles, a daily newsletter, and other options.

     
  • richardmitnick 10:38 am on April 5, 2017 Permalink | Reply
    Tags: , , New geometrical framework, Optical microcomponents, phys.org, Sculpting optical microstructures with slight changes in chemistry, Self-assembled crystal microstructures,   

    From Harvard Engineering and Applied Sciences and Wyss Institute of Biologically Inspired Engineeringvia phys.org: “Sculpting optical microstructures with slight changes in chemistry” 

    Harvard School of Engineering and Applied Sciences
    Harvard John A. Paulson School of Engineering and Applied Sciences

    Harvard bloc tiny
    Wyss Institute bloc
    Wyss Institute

    phys.org

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    A mathematical model (left) uses a geometrical framework to explain how previous patterns grew and predict new carbonate-silica structures (right, imaged by scanning electron microscopy). Credit: Wim L. Noorduin/ C. Nadir Kaplan/ Harvard University

    In 2013, materials scientists at the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) and the Wyss Institute of Biologically Inspired Engineering, grew a garden of self-assembled crystal microstructures. Now, applied mathematicians at SEAS and Wyss have developed a framework to better understand and control the fabrication of these microstructures.

    Together, the researchers used that framework to grow sophisticated optical microcomponents.

    The research is published in Science.

    When it comes to the fabrication of multifunctional materials, nature has humans beat by miles. Marine mollusks can embed photonic structures into their curved shells without compromising shell strength; deep sea sponges evolved fiber optic cables to direct light to symbiotically living organisms; and brittlestars cover their skeletons with lenses to focus light into the body to “see” at night. During growth, these sophisticated optical structures tune tiny, well-defined curves and hollow shapes to better guide and trap light.

    Manufacturing complex bio-inspired shapes in the lab is often time consuming and costly. The breakthrough in 2013 was led by materials scientists Joanna Aizenberg, the Amy Smith Berylson Professor of Materials Science and Chemistry and Chemical Biology and core faculty member of the Wyss Institute and former postdoctoral fellow Wim L. Noorduin. The research allowed researchers to fabricate delicate, flower-like structures on a substrate by simply manipulating chemical gradients in a beaker of fluid. These structures, composed of carbonate and glass, form a bouquet of thin walls.

    What that research lacked then was a quantitative understanding of the mechanisms involved that would enable even more precise control over these structures.

    Enter the theorists.

    Inspired by the theory to explain solidification and crystallization patterns, L. Mahadevan, the Lola England de Valpine Professor of Applied Mathematics, Physics, and Organismic and Evolutionary Biology, and postdoctoral fellow C. Nadir Kaplan, developed a new geometrical framework to explain how previous precipitation patterns grew and even predicted new structures.

    Mahadevan is also core member of the Wyss Institute.

    In experiments, the shape of the structures can be controlled by changing the pH of the solution in which the shapes are fabricated.

    “At high pH, these structures grow in a flat manner and you get flat shapes, like side of a vase,” said Kaplan, co-first author of the paper. “At low pH, the structure starts to curve and you get helical structures.”

    When Kaplan solved the resulting equations as a function of pH, with a mathematical parameter standing in for the chemical change, he found that he could recreate all the shapes developed by Noorduin and Aizenberg—and come up with new ones.

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    Researchers used a new framework to grow sophisticated optical microcomponents, including trumpet-shaped assemblages that operate as waveguides. Credit: Wim L. Noorduin/Harvard University

    “Once we understood the growth and form of these structures and we could quantify them; our goal was to use the theory to come up with a strategy to build optical structures from the bottom up,” said Kaplan.

    Kaplan and Noorduin worked together to grow resonators, waveguides and beam splitters.

    “When we had the theoretical framework, we were able to show the same process experimentally,” said Noorduin, co-first author. “Not only were we able to grow these microstructures, but we could also demonstrate their ability to conduct light.”

    Noorduin is now a group lead at the Dutch materials research organization AMOLF.

    “The approach may provide a scalable, inexpensive and accurate strategy to fabricate complex three-dimensional microstructures, which cannot be made by top-down manufacturing and tailor them for magnetic, electronic, or optical applications,” said Joanna Aizenberg, co-author of the paper.

    “Our theory reveals that, in addition to growth, carbonate-silica structures can also undergo bending along the edge of their thin walls,” said Mahadevan, the senior author of the paper. “This additional degree of freedom is typically lacking in conventional crystals, such as a growing snowflake. This points to a new kind of growth mechanism in mineralization, and because the theory is independent of absolute scale, it may be adapted to other geometrically constrained growth phenomena in physical and biological systems.”

    Next, the researchers hope to model how groups of these structures compete against each other for chemicals, like trees in a forest competing for sunlight.

    See the full article here .

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    Wyss Institute campus

    The Wyss (pronounced “Veese”) Institute for Biologically Inspired Engineering uses Nature’s design principles to develop bioinspired materials and devices that will transform medicine and create a more sustainable world.

    Working as an alliance among Harvard’s Schools of Medicine, Engineering, and Arts & Sciences, and in partnership with Beth Israel Deaconess Medical Center, Boston Children’s Hospital, Brigham and Women’s Hospital, Dana Farber Cancer Institute, Massachusetts General Hospital, the University of Massachusetts Medical School, Spaulding Rehabilitation Hospital, Tufts University, and Boston University, the Institute crosses disciplinary and institutional barriers to engage in high-risk research that leads to transformative technological breakthroughs.

    Through research and scholarship, the Harvard School of Engineering and Applied Sciences (SEAS) will create collaborative bridges across Harvard and educate the next generation of global leaders. By harnessing the power of engineering and applied sciences we will address the greatest challenges facing our society.

    Specifically, that means that SEAS will provide to all Harvard College students an introduction to and familiarity with engineering and technology as this is essential knowledge in the 21st century.

    Moreover, our concentrators will be immersed in the liberal arts environment and be able to understand the societal context for their problem solving, capable of working seamlessly withothers, including those in the arts, the sciences, and the professional schools. They will focus on the fundamental engineering and applied science disciplines for the 21st century; as we will not teach legacy 20th century engineering disciplines.

    Instead, our curriculum will be rigorous but inviting to students, and be infused with active learning, interdisciplinary research, entrepreneurship and engineering design experiences. For our concentrators and graduate students, we will educate “T-shaped” individuals – with depth in one discipline but capable of working seamlessly with others, including arts, humanities, natural science and social science.

    To address current and future societal challenges, knowledge from fundamental science, art, and the humanities must all be linked through the application of engineering principles with the professions of law, medicine, public policy, design and business practice.

    In other words, solving important issues requires a multidisciplinary approach.

    With the combined strengths of SEAS, the Faculty of Arts and Sciences, and the professional schools, Harvard is ideally positioned to both broadly educate the next generation of leaders who understand the complexities of technology and society and to use its intellectual resources and innovative thinking to meet the challenges of the 21st century.

    Ultimately, we will provide to our graduates a rigorous quantitative liberal arts education that is an excellent launching point for any career and profession.

     
  • richardmitnick 4:14 pm on March 29, 2017 Permalink | Reply
    Tags: , , , , phys.org, R.I.T., Satellite galaxies at edge of Milky Way coexist with dark matter   

    From RIT via phys.org: “Satellite galaxies at edge of Milky Way coexist with dark matter” 

    Rochester Institute of Technology

    phys.org

    March 29, 2017
    Susan Gawlowicz

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    The Large Magelanic Cloud is a well-known satellite or dwarf galaxy that closely orbits the Milky Way and is visible in Earth’s southern hemisphere. RIT researchers make the case for the existence of “missing” satellite galaxies that are cloaked in dark matter and cannot be directly observed. Credit:NASA/ESA Hubble

    Research conducted by scientists at Rochester Institute of Technology rules out a challenge to the accepted standard model of the universe and theory of how galaxies form by shedding new light on a problematic structure.

    The vast polar structure—a plane of satellite galaxies at the poles of the Milky Way—is at the center of a tug-of-war between scientists who disagree about the existence of mysterious dark matter, the invisible substance that, according to some scientists, comprises 85 percent of the mass of the universe.

    A paper accepted for publication in the Monthly Notices for the Royal Astronomical Society bolsters the standard cosmological model, or the Cold Dark Matter paradigm, by showing that the vast polar structure formed well after the Milky Way and is an unstable structure.

    The study, Is the Vast Polar Structure of Dwarf Galaxies a Serious Problem for CDM?— available online at https://arxiv.org/abs/1612.07325 was co-authored by Andrew Lipnicky, a Ph.D. candidate in RIT’s astrophysical sciences and technology program, and Sukanya Chakrabarti, assistant professor in RIT’s School of Physics and Astronomy, whose grant from the National Science Foundation supported the research.

    Lipnicky and Chakrabarti analyze the distribution of the classical Milky Way dwarf galaxies that form the vast polar structure and compares it to simulations of the “missing” or subhalo dwarf galaxies thought to be cloaked in dark matter.

    Using motion measurements, the authors traced the orbits of the classical Milky Way satellites backward in time. Their simulations showed the vast polar structure breaking up and dispersing, indicating that the plane is not as old as originally thought and formed later in the evolution of the galaxy. This means that the vast polar structure of satellite galaxies may be a transient feature, Chakrabarti noted.

    “If the planar structure lasted for a long time, it would be a different story,” Chakrabarti said. “The fact that it disperses so quickly indicates that the structure is not dynamically stable. There is really no inconsistency between the planar structure of dwarf galaxies and the current cosmological paradigm.”

    The authors removed the classical Milky Way satellites Leo I and Leo II from the study when orbital analyses determined that the dwarf galaxies were not part of the original vast polar structure but later additions likely snatched from the Milky Way. A comparison excluding Leo I and II reveals a similar plane shared by classical galaxies and their cloaked counterparts.

    “We tried many different combinations of the dwarf galaxies, including distributions of dwarfs that share similar orbits, but in the end found that the plane always dispersed very quickly,” Lipnicky said.

    Opposing scientific thought rejects the existence of dark matter. This camp calls into question the standard cosmological paradigm that accepts both a vast polar structure of satellite galaxies and a hidden plane of dark-matter cloaked galaxies. Lipnicky and Chakrabarti’s study supports the co-existence of these structures and refutes the challenge to the accepted standard model of the universe.

    Their research concurs with a 2016 study led by Nuwanthika Fernando, from the University of Sydney, which found that certain Milky Way planes are unstable in general. The paper published in the Monthly Notices for the Royal Astronomical Society.

    See the full article here .


    R.I.T. campus

     
  • richardmitnick 10:42 am on March 23, 2017 Permalink | Reply
    Tags: , , , phys.org, , Scientists switch on 'artificial sun' in German lab   

    From DLR via phys.org: “Scientists switch on ‘artificial sun’ in German lab” 

    DLR Bloc

    German Aerospace Center

    phys.org

    March 23, 2017

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    In this March 21, 2017 photo engineer Volkmar Dohmen stands in front of xenon short-arc lamps in the DLR German national aeronautics and space research center in Juelich, western Germany. The lights are part of an artificial sun that will be used for research purposes. (Caroline Seidel/dpa via AP)

    Scientists in Germany are flipping the switch on what’s being described as “the world’s largest artificial sun,” hoping it will help shed light on new ways of making climate-friendly fuel.

    The “Synlight” experiment in Juelich, about 30 kilometers (19 miles) west of Cologne, consists of 149 giant spotlights normally used for film projectors.

    Starting Thursday, scientists from the German Aerospace Center will start experimenting with this dazzling array to try to find ways of tapping the enormous amount of energy that reaches Earth in the form of light from the sun.

    One area of research will focus on how to efficiently produce hydrogen, a first step toward making artificial fuel for airplanes.

    The experiment uses as much electricity in four hours as a four-person household would in a year.

    2
    n this March 21, 2017 photo engineer Volkmar Dohmen stands in front of xenon short-arc lamps in the DLR German national aeronautics and space research center in Juelich, western Germany. The lights are part of an artificial sun that will be used for research purposes. (Caroline Seidel/dpa via AP)

    See the full article here .

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    DLR Center

    DLR is the national aeronautics and space research centre of the Federal Republic of Germany. Its extensive research and development work in aeronautics, space, energy, transport and security is integrated into national and international cooperative ventures. In addition to its own research, as Germany’s space agency, DLR has been given responsibility by the federal government for the planning and implementation of the German space programme. DLR is also the umbrella organisation for the nation’s largest project management agency.

    DLR has approximately 8000 employees at 16 locations in Germany: Cologne (headquarters), Augsburg, Berlin, Bonn, Braunschweig, Bremen, Goettingen, Hamburg, Juelich, Lampoldshausen, Neustrelitz, Oberpfaffenhofen, Stade, Stuttgart, Trauen, and Weilheim. DLR also has offices in Brussels, Paris, Tokyo and Washington D.C.

     
  • richardmitnick 8:48 am on March 20, 2017 Permalink | Reply
    Tags: Anderson limit, , How small can superconductors be?, , P.W. Anderson, Parity effect, phys.org, , Richardson-Gaudin models   

    From phys.org: “How small can superconductors be?” 

    physdotorg
    phys.org

    March 20, 2017
    Lisa Zyga

    1
    Topographic image of a lead nanocrystal used in the study. Scale bar: 10 nm. Credit: Vlaic et al. Nature Communications

    For the first time, physicists have experimentally validated a 1959 conjecture that places limits on how small superconductors can be. Understanding superconductivity (or the lack thereof) on the nanoscale is expected to be important for designing future quantum computers, among other applications.

    In 1959, physicist P.W. Anderson conjectured that superconductivity can exist only in objects that are large enough to meet certain criteria. Namely, the object’s superconducting gap energy must be larger than its electronic energy level spacing—and this spacing increases as size decreases. The cutoff point (where the two values are equal) corresponds to a volume of about 100 nm3. Until now it has not been possible to experimentally test the Anderson limit due to the challenges in observing superconducting effects at this scale.

    In the new study published in Nature Communications, Sergio Vlaic and coauthors at the University Paris Sciences et Lettres and French National Centre for Scientific Research (CNRS) designed a nanosystem that allowed them to experimentally investigate the Anderson limit for the first time.

    The Anderson limit arises because, at very small scales, the mechanisms underlying superconductivity essentially stop working. In general, superconductivity occurs when electrons bind together to form Cooper pairs. Cooper pairs have a slightly lower energy than individual electrons, and this difference in energy is the superconducting gap energy. The Cooper pairs’ lower energy inhibits electron collisions that normally create resistance. If the superconducting gap energy gets too small and vanishes—which can occur, for example, when the temperature increases—then the electron collisions resume and the object stops being a superconductor.

    The Anderson limit shows that small size is another way that an object may stop being a superconductor. However, unlike the effects of increasing the temperature, this is not because smaller objects have a smaller superconducting gap energy. Instead, it arises because smaller crystals have fewer electrons, and therefore fewer electron energy levels, than larger crystals do. Since the total possible electron energy of an element stays the same, regardless of size, smaller crystals have larger spacings between their electron energy levels than larger crystals do.

    According to Anderson, this large electronic energy level spacing should pose a problem, and he expected superconductivity to disappear when the spacing becomes larger than the superconducting gap energy. The reason for this, generally speaking, is that one consequence of increased spacing is a decrease in potential energy, which interferes with the competition between kinetic and potential energy that is necessary for superconductivity to occur.

    To investigate what happens to the superconductivity of objects around the Anderson limit, the scientists in the new study prepared large quantities of isolated lead nanocrystals ranging in volume from 20 to 800 nm3.

    Although they could not directly measure the superconductivity of such tiny objects, the researchers could measure something called the parity effect, which results from superconductivity. When an electron is added to a superconductor, the additional energy is partly affected by whether there is an even or odd number of electrons (the parity), which is due to the electrons forming Cooper pairs. If the electrons don’t form Cooper pairs, there is no parity effect, indicating no superconductivity.

    Although the parity effect has previously been observed in large superconductors, this study is the first time that it has been observed in small nanocrystals approaching the Anderson limit. In accordance with Anderson’s predictions from more than 50 years ago, the researchers observed the parity effect for larger nanocrystals, but not for the smallest nanocrystals below approximately 100 nm3.

    The results not only validate the Anderson conjecture, but also extend to a more general area, the Richardson-Gaudin models. These models are equivalent to the conventional theory of superconductivity, the Bardeen Cooper Schrieffer theory, for very small objects.

    “Our experimental demonstration of the Anderson conjecture is also a demonstration of the validity of the Richardson-Gaudin models,” coauthor Hervé Aubin at the University Paris Sciences et Lettres and CNRS told Phys.org. “The Richardson-Gaudin models are an important piece of theoretical works because they can be solved exactly and apply to a wide range of systems; not only to superconducting nanocrystals but also to atomic nuclei and cold fermionic atomic gas, where protons and neutrons, which are fermions like electrons, can also form Cooper pairs.”

    On the more practical side, the researchers expect the results to have applications in future quantum computers.

    “One of the most interesting applications of superconducting islands is their use as Cooper pair boxes employed in quantum bits, the elemental unit of a hypothetical quantum computer,” Aubin said. “So far, Cooper pair boxes used in qubits are much larger than the Anderson limit. Upon reducing the size of the Cooper pair box, quantum computer engineers will eventually have to cope with superconductivity at the Anderson limit.”

    See the full article here .

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    About Phys.org in 100 Words

    Phys.org™ (formerly Physorg.com) is a leading web-based science, research and technology news service which covers a full range of topics. These include physics, earth science, medicine, nanotechnology, electronics, space, biology, chemistry, computer sciences, engineering, mathematics and other sciences and technologies. Launched in 2004, Phys.org’s readership has grown steadily to include 1.75 million scientists, researchers, and engineers every month. Phys.org publishes approximately 100 quality articles every day, offering some of the most comprehensive coverage of sci-tech developments world-wide. Quancast 2009 includes Phys.org in its list of the Global Top 2,000 Websites. Phys.org community members enjoy access to many personalized features such as social networking, a personal home page set-up, RSS/XML feeds, article comments and ranking, the ability to save favorite articles, a daily newsletter, and other options.

     
  • richardmitnick 9:57 am on March 14, 2017 Permalink | Reply
    Tags: , , , , phys.org,   

    From phys.org: “Astronomers discover 16 new high-redshift quasars” 

    physdotorg
    phys.org

    March 14, 2017
    Tomasz Nowakowski

    1
    The color track of quasar at z = 5 to 6 (red dots and line) with a step of ∆z = 0.1, generated by calculating the mean colors of simulated quasars at each redshift bin. The contours show the locus of M dwarfs, from early type to late type. The cyan contours denote M1-M3 dwarfs, the orange contours denote M4-M6 dwarfs and the purple contours denote M7-M9 dwarfs. Clearly, z ∼ 5.5 quasars are serious contaminated by late type M dwarfs. Credit: Yang et al., 2017.

    Using a new color selection technique, astronomers have detected 16 new luminous, high-redshift quasars. The discovery could be very important for understanding of the early universe, as such high-redshift, quasi-stellar objects provide essential clues on the evolution of the intergalactic medium, quasar evolution and early super-massive black hole growth. The findings were presented in a paper published Mar. 10 on the arXiv pre-print repository.

    High-redshift quasars (at redshift higher than 5.0) are very difficult to find using conventional color selections. This is due to their low spatial density and high contaminants from cool dwarfs. Among more than 300,000 quasars discovered to date, only 290 of them are at redshift higher than 5.0. The scientific community is especially interested in high-redshift quasars at redshift between 5.3 and 5.7, due to their optical colors, which are similar to those of late-type stars. Only about 30 such objects have been found so far.

    With the aim of filling this gap of known quasars at redshift ranging from 5.3 to 5.7, a team of astronomers led by Jinyi Yang of the Peking University in Beijing, China, has developed a new optical/infrared color selection technique. The method is based on optical, near-infrared and mid-infrared photometric data from Sloan Digital Sky Survey (SDSS), UKIRT InfraRed Deep Sky Surveys – Large Area Survey (ULAS), VISTA Hemisphere Survey (VHS) and NASA’s Wide field Infrared Survey Explorer (WISE).


    SDSS Telescope at Apache Point Observatory, NM, USA


    UKIRT, located on Mauna Kea, Hawai’i, USA as part of Mauna Kea Observatory


    NASA/WISE Telescope

    The method has proved its worth as the researchers were able to find 16 new luminous, high-redshift quasars at redshift within the desired range. The observations were carried out between October 2014 and November 2015.

    “In this paper, we report initial results from a new search that focuses on the selection of z ~ 5.5 quasars,” the team wrote.

    Among the newly discovered quasi-stellar objects, J113414.23+082853.3 is the one with the highest redshift – at 5.69. This quasar also showcases strong Lyman-alpha emission and strong intergalactic medium absorption blueward of Lyman-alpha line.

    Another interesting new quasar found by the researchers is J152712.86+064121.9 (at 5.57). It is a weak line quasar with a very weak Lyman-alpha emission line and no other obvious emission features. However, the team revealed that its redshift was measured by matching the continuum to template; thus, its redshift uncertainty is a little larger than others.

    The scientists underline the importance of their research, noting that it could help us better understand the evolution of quasars at redshift from 5.0 to 6.0, over the post-reionization epoch.

    “The physical conditions of the post-reionization intergalactic medium, at z ~ 5-6, provides the basic boundary conditions of models of reionization, such as the evolution of intergalactic temperature, photon mean free path, metallicity and the impact of helium reionization. They place strong constraints on reionization topology as well as on the sources of reionization and chemical feedback by early galaxy population,” the paper reads.

    The team now plans to publish another paper in which a broader sample of high-redshift quasars will be presented. This study will also include the data from the UKIRT Hemisphere Survey (UHS), Pan-STARRS PS1 Survey and the VLT Survey Telescope (VST) ATLAS.


    Pan-STARRS1 located on Haleakala, Maui, HI, USA


    ESO VST telescope, at ESO’s Paranal Observatory

    See the full article here .

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    About Phys.org in 100 Words

    Phys.org™ (formerly Physorg.com) is a leading web-based science, research and technology news service which covers a full range of topics. These include physics, earth science, medicine, nanotechnology, electronics, space, biology, chemistry, computer sciences, engineering, mathematics and other sciences and technologies. Launched in 2004, Phys.org’s readership has grown steadily to include 1.75 million scientists, researchers, and engineers every month. Phys.org publishes approximately 100 quality articles every day, offering some of the most comprehensive coverage of sci-tech developments world-wide. Quancast 2009 includes Phys.org in its list of the Global Top 2,000 Websites. Phys.org community members enjoy access to many personalized features such as social networking, a personal home page. set-up, RSS/XML feeds, article comments and ranking, the ability to save favorite articles, a daily newsletter, and other options.

     
  • richardmitnick 4:58 pm on March 8, 2017 Permalink | Reply
    Tags: , , , BRITE (BRight Target Explorer) Constellation project, , Iota Orionis: Pulsating beacon of a constellation, nanosats, phys.org, Ritter Observatory   

    From phys.org: “Iota Orionis: Pulsating beacon of a constellation” 

    physdotorg
    phys.org

    March 8, 2017

    1
    Iota Orionis is a binary star system and is easily visible with the naked eye, being the brightest star in the constellation Orion’s sword. Credit: Danielle Futselaar

    Astronomers from the BRITE (BRight Target Explorer) Constellation project and Ritter Observatory have discovered a repeating one-per-cent spike in the light of a very massive star which could change our understanding of such stars. Iota Orionis is a binary star system and is easily visible with the naked eye, being the brightest star in the constellation Orion’s sword. Its unique variability, reported in the journal Monthly Notices of the Royal Astronomical Society, was discovered using the world’s smallest astronomical space satellites, referred to as “nanosats”. “As the first functional nanosatellite astronomy mission, the BRITE-Constellation is at the vanguard of this coming space revolution,” said Canadian BRITE-Constellation principal investigator Gregg Wade, of Royal Military College of Canada, Ont.

    The light from Iota Orionis is relatively stable 90 per cent of the time but then dips rapidly followed by a large spike. “The variations look strikingly similar to an electrocardiogram showing the sinus rhythms of the heart, and are known as heartbeat systems,” said Herbert Pablo, the project’s principal investigator, a post-doctoral researcher at Université de Montréal and member of the Centre for Research in Astrophysics of Quebec (CRAQ). This unusual variation is the result of the interaction of two stars in a highly elliptical 30-day orbit around each other.

    While the two stars spend the majority of their time far apart, they do come nearly eight times closer together for a short time once every orbit. At that point the gravitational force between the two stars becomes so strong that it rapidly distorts their shapes, like pulling on the end of a balloon, causing the unusual changes in light. Iota Orionis represents the first time this effect has been seen in such a massive system (35 times the mass of the Sun), an order of magnitude larger than any in previously known systems, and allows for direct determination of the masses and radii of the components.

    A shaking star is like an open book

    Even more interesting is that these systems allow us to peer inside the stars themselves. “The intense gravitational force between the stars as they move closer together triggers quakes in the star, allowing us to probe the star’s inner workings, just as we do for the Earth’s interior during Earthquakes,” said Pablo. The phenomenon of quakes is very rare in massive stars in general and this is the first time induced quakes have ever been seen in a star this massive, let alone one whose mass and radius are known. These unprecedented quakes have also led to the first real clues to how such stars will evolve.

    Astronomers are hopeful that this discovery will provide the initiative to search for other such systems, creating a fundamental shift in how we study the evolution of massive stars. This is important, since massive stars are laboratories of elements essential to human life.

    See the full article here .

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    About Phys.org in 100 Words

    Phys.org™ (formerly Physorg.com) is a leading web-based science, research and technology news service which covers a full range of topics. These include physics, earth science, medicine, nanotechnology, electronics, space, biology, chemistry, computer sciences, engineering, mathematics and other sciences and technologies. Launched in 2004, Phys.org’s readership has grown steadily to include 1.75 million scientists, researchers, and engineers every month. Phys.org publishes approximately 100 quality articles every day, offering some of the most comprehensive coverage of sci-tech developments world-wide. Quancast 2009 includes Phys.org in its list of the Global Top 2,000 Websites. Phys.org community members enjoy access to many personalized features such as social networking, a personal home page set-up, RSS/XML feeds, article comments and ranking, the ability to save favorite articles, a daily newsletter, and other options.

     
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