46,733 research outputs found
Telerobotic workstation design aid
Telerobot systems are being developed to support a number of space mission applications. In low earth orbit, telerobots and teleoperated manipulators will be used in shuttle operations and space station construction/maintenance. Free flying telerobotic service vehicles will be used at low and geosynchronous orbital operations. Rovers and autonomous vehicles will be equipped with telerobotic devices in planetary exploration. In all of these systems, human operators will interact with the robot system at varied levels during the scheduled operations. The human operators may be in either orbital or ground-based control systems. To assure integrated system development and maximum utility across these systems, designers must be sensitive to the constraints and capabilities that the human brings to system operation and must be assisted in applying these human factors to system development. The simulation and analysis system is intended to serve the needs of system analysis/designers as an integrated workstation in support of telerobotic design
Submillimeter-wave emission of three Galactic red novae: cool molecular outflows produced by stellar mergers
Red novae are optical transients erupting at luminosities typically higher
than those of classical novae. Their outbursts are believed to be caused by
stellar mergers. We present millimeter/submillimeter-wave observations with
ALMA and SMA of the three best known Galactic red novae, V4332 Sgr, V1309 Sco,
and V838 Mon. The observations were taken 22, 8, and 14 yr after their
respective eruptions and reveal the presence of molecular gas at excitation
temperatures of 35-200 K. The gas displays molecular emission in rotational
transitions with very broad lines (full width 400 km\s). We found
emission of CO, SiO, SO, SO (in all three red novae), HS (covered only
in V838 Mon) and AlO (present in V4332 Sgr and V1309 Sco). No anomalies were
found in the isotopic composition of the molecular material and the chemical
(molecular) compositions of the three red novae appear similar to those of
oxygen-rich envelopes of classical evolved stars (RSGs, AGBs, post-AGBs). The
minimum masses of the molecular material that most likely was dispersed in the
red-nova eruptions are 0.1, 0.01, and 10 M for V838 Mon, V4332
Sgr, and V1309 Sco, respectively. The molecular outflows in V4332 Sgr and V1309
Sco are spatially resolved and appear bipolar. The kinematic distances to V1309
Sco and V4332 Sgr are 2.1 and 4.2 kpc, respectively. The kinetic energy stored
in the ejecta of the two older red-nova remnants of V838 Mon and V4332 Sgr is
of order erg, similar to values found for some post-AGB (pre-PN)
objects whose bipolar ejecta were also formed in a short-duration eruption. Our
observations strengthen the link between these post-AGB objects and red novae
and support the hypothesis that some of the post-AGB objects were formed in a
common-envelope ejection event or its most catastrophic outcome, a merger.Comment: 19 pages, 13 figures, accepted to A&
Application of Origin Rules in Kaesong Industrial Complex, North Korea
Under the expansion of regional economic integration, a product may be assembled in more than one country, creating the problem to determine the origin of the product. This paper aims to analyze the issue to recognize products manufactured in Kaesong Industrial Complex, North Korea, as products originating from South Korea. Sebagai akibat dari berkembangnya kesatuan-kesatuan ekonomi regional, suatu produk dapat diproduksi di lebih dari satu negara. Hal ini menimbulkan masalah dalam menentukan asal negara produk tersebut. Penelitian ini bertujuan untuk mempelajari isu untuk menetapkan produk-produk dari Kompleks Industri Kaesong, Korea Utara, sebagai produk yang berasal dari Korea Selatan
First order phase transition in the Quantum Adiabatic Algorithm
We simulate the quantum adiabatic algorithm (QAA) for the exact cover problem
for sizes up to N=256 using quantum Monte Carlo simulations incorporating
parallel tempering. At large N we find that some instances have a discontinuous
(first order) quantum phase transition during the evolution of the QAA. This
fraction increases with increasing N and may tend to 1 for N -> infinity.Comment: 5 pages, 3 figures. Replaced with published version; two figures
slightly changed and some small changes to the tex
Exploring Hospitals\u27 Use of Facebook: Thematic Analysis
Background: Although health care organizations such as hospitals and clinics have widely embraced social media as a means to educate the community on health topics and increase patient loyalty and satisfaction, little is known about the content these organizations actually share when using social media channels.
Objective: This study aimed to explore the types of content US hospitals post on their Facebook pages and how hospitals’ Facebook activities differ with regard to content types.
Methods: We collected and thematically analyzed more than 1700 Facebook posts made over a 3-month period by 17 US hospitals. During the first phase, the 2 researchers coded a set of 159 posts and created an initial thematic web of content. During the second phase, the researchers coded the remaining posts and then revised, refined, and validated the initial web of content accordingly. Coding consensus was achieved on 1184 of the 1548 analyzable sampled posts (76.49%).
Results: We identified a list of 13 unique health social media post themes and classified those themes into 3 thematic groups that included announcing, sharing, and recognizing activities. The most frequently used theme was sharing health information, which appeared in 35.81% (424/1184) of the posts analyzed. Such posts sought to provide health tips and advice to community members. Recognizing special days and recognizing employees were the second and third most frequently used themes, respectively, with 14.95% (177/1184) and 11.82% (140/1184) of the posts containing those themes. The frequency of these themes was surprising as the content was geared more toward stakeholders internal to the organization, although most previous literature has focused on social media as a tool to connect with external stakeholders. In addition, we found many of the posts involved more than one theme, and selected sets of themes co-occurred frequently. For example, 25.4% (45/177) of the posts recognizing special days also included content to share health information, and approximately 38% (32/85) of the posts announcing research activities also included content to share health information. Finally, we found similarities and differences between the sampled hospitals in terms of the types of content they posted more frequently on their Facebook pages.
Conclusions: Hospitals use Facebook as an inexpensive way to educate people on health and wellness topics and to communicate different types of information and news to the public audience. Hospitals and clinics that are expanding their social media activities or are starting to embark on social media strategies can use the results of this study to better formulate their activities on Facebook
PO and PN in the wind of the oxygen-rich AGB star IK Tau
Phosphorus-bearing compounds have only been studied in the circumstellar
environments (CSEs) of the asymptotic giant branch (AGB) star IRC +10216 and
the protoplanetary nebula CRL 2688, both C-rich objects, and the O-rich red
supergiant VY CMa. The current chemical models cannot reproduce the high
abundances of PO and PN derived from observations of VY CMa. No observations
have been reported of phosphorus in the CSEs of O-rich AGB stars. We aim to set
observational constraints on the phosphorous chemistry in the CSEs of O-rich
AGB stars, by focussing on the Mira-type variable star IK Tau. Using the IRAM
30m telescope and the Submillimeter Array (SMA), we observed four rotational
transitions of PN (J=2-1,3-2,6-5,7-6) and four of PO
(J=5/2-3/2,7/2-5/2,13/2-11/2,15/2-13/2). The IRAM 30m observations were
dedicated line observations, while the SMA data come from an unbiased spectral
survey in the frequency range 279-355 GHz.
We present the first detections of PN and PO in an O-rich AGB star and
estimate abundances X(PN/H2) of about 3x10^-7 and X(PO/H2) in the range
0.5-6.0x10^-7. This is several orders of magnitude higher than what is found
for the C-rich AGB star IRC +10216. The diameter (<=0.7") of the PN and PO
emission distributions measured in the interferometric data corresponds to a
maximum radial extent of about 40 stellar radii. The abundances and the spatial
occurrence of the molecules are in very good agreement with the results
reported for VY CMa. We did not detect PS or PH3 in the survey. We suggest that
PN and PO are the main carriers of phosphorus in the gas phase, with abundances
possibly up to several 10^-7. The current chemical models cannot account for
this, underlining the strong need for updated chemical models that include
phosphorous compounds.Comment: Accepted for publication in Astronomy & Astrophysics, 10 pages, 8
figure
Evidence of micro-continent entrainment during crustal accretion
Peer reviewedPublisher PD
Too good to waste: Creating biochar from cleared vegetation as a soil improver and carbon sink
Road construction has a considerable carbon footprint and is likely to be impacted significantly by international and national responses to climate change. Although avoidance of carbon emissions during the design and construction phases is preferred, it is inevitable that some carbon emissions will result in large projects, due to the carbon intensive nature of road construction.
Typical offset projects have focused around the biosequestration of carbon, including large-scale tree planting. Whilst tree planting projects achieve broader benefits from reafforestation, concerns surrounding the biodiversity value of largely monoculture, agro-forestry projects are adding to traditional criticisms such as the measurability and permanency.
Concerns over tree planting as an approach to offsetting have paved the way for consideration of other biological methods for carbon sequestration that are better able to respond to tests of measurability and permanency and attempt to preserve the biodiversity value of cleared land.
Biochar, charcoalised woody biomass, is a soil improver, which is being investigated globally due to its potential to store carbon in the soil for extremely long time periods. On-site production of biochar using cleared vegetation is an approach to carbon offsetting that allows for both the sequestration of carbon in the soil and enhances revegetation activities in the road reserve.
Low technology approaches are practical, using existing road construction equipment to dig pits in which the vegetation is slowly carbonised through low oxygen combustion. High technology but portable approaches for on-site generation using modern biomass to energy conversion technologies (pyrolysis and gasification) are also possible and able to produce biochar and renewable fuels, which can be used in a number of conventional generation technologies such as internal combustion engines and turbines. Roadside vegetation used in modern biomass pyrolysis technologies has the potential to produce around 30 kg of carbon sequestration for each gigajoule of renewable fuel produced.
Biochar may sequester up to 50 per cent of the carbon in the original vegetation, having the potential to become an important part of future revegetation activities in road construction This paper will discuss several approaches to onsite biochar production from road vegetation, in particular a recent trial from Western Australia and the opportunities for reducing carbon emissions and the sequestration of carbon that would otherwise be burnt or left to rapidly decay as chipped or mulched material
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