A candidate planetary-mass object with a photoevaporating disk in Orion

In this work, we report the discovery of a candidate planetary-mass object with a photoevaporating protoplanetary disk, Proplyd 133-353, which is near the massive star $\theta^{1}$ Ori C at the center of the Orion Nebula Cluster (ONC). The object was known to have extended emission pointing away from $\theta^{1}$ Ori C, indicating ongoing external photoevaporation. Our near-infrared spectroscopic data suggests that the central source of Proplyd 133-353 is substellar ($\sim$M9.5), might have a mass probably less than 13 Jupiter mass and an age younger than 0.5 Myr. Proplyd 133-353 shows a similar ratio of X-ray luminosity to stellar luminosity to other young stars in the ONC with a similar stellar luminosity, and has a similar proper motion to the mean one of confirmed ONC members. We propose that Proplyd 133-353 was formed in a very low-mass dusty cloud near $\theta^{1}$ Ori C as a second-generation of star formation, which can explain both its young age and the presence of its disk.Comment: 6 pages, 4 figures. Accepted for publication in ApJ

The Effect of Organizational Structure on Open Innovation: A Quadratic Equation

AbstractOpen innovation has recently begun to receive increasing attention in organizational research. Studies on open innovation have emphasized the impact of organizational structure on both inbound and outbound open innovation but have tended to focus on the former. This study attempts to provide a better understanding of open innovation within the context of open source by examining 2,811 projects, especially in GitHub. The analysis results reveal that the decentralization of decision-making encourages both inbound and outbound open innovation. The impact of the decentralization of decision-making differs between inbound and outbound open innovation, a finding that both scholars and practitioners must consider

Want-To vs. Have-To Socializations in Social Network Sites: Fear of Isolation, Jealousy, and Tie Strengths

As social network sites (SNS) expand the boundaries of one’s social life, we often observe encounters between two different types of motivations for socialization - I want-to socialize vs. I have-to socialize. SNS at present are considered commodities. People do not always start using SNS because they want to, but often because everyone else is using it; people do not wish to be isolated from social circles. This study aims to examine different types of user motivations in SNS and observe how these lead to actual socialization behaviours with different progress dynamics. We apply constraint- and dedication- based relationship framework to distinguish motivations and identify constructs for each motivation. We plan to collect data from one of the major SNS to validate how their socialization intentions are differently realized into actual behaviours. We develop a two-staged research model and this research-in-progress presents the result of the pilot study conducted for the first stage. We also discuss how the second stage of the study will be executed, and how it will benefit the related literature when the project is successfully completed

The low-mass stellar population in the young cluster Tr37: Disk evolution, accretion, and environment

We present a study of accretion and protoplanetary disks around M-type stars in the 4 Myr-old cluster Tr37. With a well-studied solar-type population, Tr37 is a benchmark for disk evolution. We used low-resolution spectroscopy to identify 141 members (78 new) and 64 probable members, mostly M-type stars. H\alpha\ emission provides information about accretion. Optical, 2MASS, Spitzer, and WISE data are used to trace the SEDs. We construct radiative transfer models to explore the structures of full-disks, pre-transition, transition, and dust-depleted disks. Including the new and previously known members, we confirm that a substantial fraction (~2/5) of disks show signs of evolution, either as radial dust evolution (transition/pre-transition disks) or as a more global evolution (low small-dust masses, dust settling, and weak/absent accretion signatures). Accretion is strongly dependent on the SED type. About half of the transition objects are consistent with no accretion, and dust-depleted disks have weak (or undetectable) accretion signatures, especially among M-type stars. The analysis of accretion and disk structure suggests a parallel evolution of dust and gas. We find several distinct classes of evolved disks, based on SED type and accretion, pointing to different disk dispersal mechanisms and probably different evolutionary paths. Dust depletion and opening of inner holes appear to be independent processes: most transition disks are not dust-depleted, and most dust-depleted disks do not require inner holes. The differences in disk structure between M-type and solar-type stars in Tr37 (4 Myr) are not as remarkable as in the young, sparse, Coronet cluster (1-2 Myr), suggesting that other factors, like the environment/interactions, are likely to play a role in the disk evolution and dispersal. Finally, we also find some evidence of clumpy star formation or mini-clusters within Tr37.Comment: 21 pages, 16 figures, plus appendix with tables and figures. Accepted by A&

Concrete delamination depth estimation using a noncontact mems ultrasonic sensor array and an optimization approach

In this study, we present a method to estimate the depth of near-surface shallow delamination in concrete using a noncontact micro-electromechanical system (MEMS) ultrasonic sensor array and an optimization-based data processing approach. The proposed approach updates the bulk wave velocities of the tested concrete element by solving an optimization problem using reference ultrasonic scanning data collected from a full-depth concrete region. Subsequently, the depth of concrete delamination is estimated by solving a separate optimization problem. Numerical simulations and laboratory experiments were conducted to evaluate the performance of the proposed ultrasonic data processing approach. The results demonstrated that the depth of shallow delamination in concrete structures could be accurately estimated

Double-peaked [OI] Profile: A Likely Signature of the Gaseous Ring around KH 15D

KH 15D is a well-known spectroscopic binary because of its unique and dramatic photometric variability. The variability is explained by a circumbinary dust ring, but the ring itself was never directly detected. We present a new interpretation of the double-peaked [OI]lambda 6300 profiles as originating from the hot disk surface of KH 15D. By modeling these profiles, we measure emitting radii between similar to 0.5 and 5 au, basically a gaseous ring very similar in radial extent to the dust ring inferred from modeling the system's photometric variability. We also discuss the possibility that external photoevaporation driven by ultraviolet photons from the nearby massive star HD 47887 has truncated the outer edge of the disk to the observed value.Collaborative NSF Astronomy & Astrophysics Research Grant [1715022, 1714229]; National Aeronautics and Space Administration [NNX15AD94G]; NASA's Science Mission DirectorateThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Shuttle-effect-free sodium–sulfur batteries derived from a Tröger's base polymer of intrinsic microporosity

Room-temperature sodium-sulfur (RT Na-S) batteries have recently gained attention as next-generation energy storage devices owing to their low cost, the abundance of sodium, and the high theoretical capacity of sulfur. However, the notorious shuttle effect, caused by the dissolution of intermediate polysulfides during cycling, limits the long-term performance of Na-S batteries. In this study, intrinsically microporous Tro center dot ger's base based polymer (PIM-EA-TB)-based carbon-sulfur composites are prepared for shuttle-effect-free RT Na-S batteries by utilizing the combination of physical confinement and covalent bonding in a single material. The composites demonstrate excellent electrochemical performance, including a negligible capacity fading over 350 cycles and a high coulombic efficiency of approximately greater than 99%.