21 research outputs found

    Search for eccentric black hole coalescences during the third observing run of LIGO and Virgo

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    Despite the growing number of confident binary black hole coalescences observed through gravitational waves so far, the astrophysical origin of these binaries remains uncertain. Orbital eccentricity is one of the clearest tracers of binary formation channels. Identifying binary eccentricity, however, remains challenging due to the limited availability of gravitational waveforms that include effects of eccentricity. Here, we present observational results for a waveform-independent search sensitive to eccentric black hole coalescences, covering the third observing run (O3) of the LIGO and Virgo detectors. We identified no new high-significance candidates beyond those that were already identified with searches focusing on quasi-circular binaries. We determine the sensitivity of our search to high-mass (total mass M>70 M⊙) binaries covering eccentricities up to 0.3 at 15 Hz orbital frequency, and use this to compare model predictions to search results. Assuming all detections are indeed quasi-circular, for our fiducial population model, we place an upper limit for the merger rate density of high-mass binaries with eccentricities 0<e≤0.3 at 0.33 Gpc−3 yr−1 at 90\% confidence level

    Outcomes and Mortality Among Adults Hospitalized With COVID-19 at US Medical Centers.

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    This cohort study assesses characteristics and outcomes among adults hospitalized with coronavirus disease 2019 (COVID-19) at US medical centers as well as COVID-19–related mortality over the initial 6 months of the pandemic

    Cavitation-Mediated Fracture Energy Dissipation in Polylactide at Rubbery Soybean Oil-Based Block Copolymer Interfaces Formed via Reactive Extrusion

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    Here, we spearhead a new approach to biopolymer impact modification that demonstrates superior performance while maintaining greater than 99% compostability. Using soybean-based monomers, a virtually untapped resource in terms of commercial volume and overall cost, a series of hyperbranched block copolymers were synthesized and melt-processed with poly(l-lactide) (PLA) to yield impact resistant all-polymer composites. Although PLA impact modification has been treated extensively, to date, the only practical solutions have relied on non-compostable petroleum-based rubbers. This study illustrates the activity of energy dissipation mechanisms such as cavitation, classically relegated to well-entangled petroleum-based rubbers, in poorly entangled hyperbranched soybean-based rubbers. Furthermore, we present a complete study of the mechanical performance and morphology of these impact modified PLA composites. The significance of combining deformation theory with a scalable green alternative to petroleum-based rubbers opens up a potential avenue for cheap compostable engineering thermoplastics.This document is the unedited Author’s version of a Submitted Work that was subsequently accepted for publication in ACS Applied Materials & Interfaces, copyright © 2022 American Chemical Society after peer review. To access the final edited and published work see DOI: 10.1021/acsami.2c10496. Posted with permission

    Cavitation-Mediated Fracture Energy Dissipation in Polylactide at Rubbery Soybean Oil-Based Block Copolymer Interfaces Formed via Reactive Extrusion

    Get PDF
    Here, we spearhead a new approach to biopolymer impact modification that demonstrates superior performance while maintaining greater than 99% compostability. Using soybean-based monomers, a virtually untapped resource in terms of commercial volume and overall cost, a series of hyperbranched block copolymers were synthesized and melt-processed with poly(l-lactide) (PLA) to yield impact resistant all-polymer composites. Although PLA impact modification has been treated extensively, to date, the only practical solutions have relied on non-compostable petroleum-based rubbers. This study illustrates the activity of energy dissipation mechanisms such as cavitation, classically relegated to well-entangled petroleum-based rubbers, in poorly entangled hyperbranched soybean-based rubbers. Furthermore, we present a complete study of the mechanical performance and morphology of these impact modified PLA composites. The significance of combining deformation theory with a scalable green alternative to petroleum-based rubbers opens up a potential avenue for cheap compostable engineering thermoplastics
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