87 research outputs found
From Castor OilâBased Multifunctional Polyols to Waterborne Polyurethanes: Synthesis and Properties
Abstract A novel castor oilâbased multifunctional polyol (CM) is fabricated through mild thiolâene photo induced reactions using castor oil (CO) and 1âthioglycerol (MPD) as building blocks. The effect of the reaction time, molar ratio of thiol to carbonâcarbon double bond, and the loadings of photoâinitiator are optimized. The resulting CM is combined with CO and employed as crossâlinkers to prepare castor oilâbased waterâborne polyurethane emulsion with desirable mechanical properties and water resistance. Owing to the incorporation of CM crossâlinker with high hydroxyl value of 371 mg KOH/g (which is 2.27 times higher than that of the CO), the prepared castor oilâbased waterborne polyurethane (CMWPU) possesses compacted 3D network structure with high crossâlinking degree, leading to improved glass transition temperature (45 °C), tensile strength (10.8 MPa), water contact angle (87.4°), and decreased water absorption rate (16.12%) with 20% CM additions. Overall, this work illustrates the feasibility of introducing bio renewable CM combined with CO to develop castor oilâbased WPU employing a sustainable development strategy
Trust in AutoML: Exploring Information Needs for Establishing Trust in Automated Machine Learning Systems
We explore trust in a relatively new area of data science: Automated Machine
Learning (AutoML). In AutoML, AI methods are used to generate and optimize
machine learning models by automatically engineering features, selecting
models, and optimizing hyperparameters. In this paper, we seek to understand
what kinds of information influence data scientists' trust in the models
produced by AutoML? We operationalize trust as a willingness to deploy a model
produced using automated methods. We report results from three studies --
qualitative interviews, a controlled experiment, and a card-sorting task -- to
understand the information needs of data scientists for establishing trust in
AutoML systems. We find that including transparency features in an AutoML tool
increased user trust and understandability in the tool; and out of all proposed
features, model performance metrics and visualizations are the most important
information to data scientists when establishing their trust with an AutoML
tool.Comment: IUI 202
The mHz quasi-regular modulations of 4U 1630--47 during its 1998 outburst
We present the results of a detailed timing and spectral analysis of the
quasi-regular modulation (QRM) phenomenon in the black hole X-ray binary 4U
1630--47 during its 1998 outburst observed by Rossi X-ray Timing Explore
(RXTE). We find that the 50-110 mHz QRM is flux dependent, and the QRM
is detected with simultaneous low frequency quasi-periodic oscillations
(LFQPOs). According to the behavior of the power density spectrum, we divide
the observations into four groups. In the first group, namely behavior A,
LFQPOs are detected, but no mHz QRM. The second group, namely behavior B, a QRM
with frequency above 88 mHz is detected and the 5 Hz and 7
Hz LFQPOs are almost overlapping. In the third group, namely behavior C, the
QRM frequency below 88 mHz is detected and the LFQPOs are significantly
separated. In the forth group, namely behavior D, neither QRM nor LFQPOs are
detected. We study the energy-dependence of the fractional rms, centroid
frequency, and phase-lag of QRM and LFQPOs for behavior B and C. We then study
the evolution of QRM and find that the frequency of QRM increases with
hardness, while its rms decreases with hardness. We also analyze the spectra of
each observation, and find that the QRM rms of behavior B has a positive
correlation with / . Finally, we give
our understanding for this mHz QRM phenomena.Comment: 14pages, 15 figure
In-orbit background simulation of a type-B CATCH satellite
The Chasing All Transients Constellation Hunters (CATCH) space mission plans
to launch three types of micro-satellites (A, B, and C). The type-B CATCH
satellites are dedicated to locating transients and detecting their
time-dependent energy spectra. A type-B satellite is equipped with lightweight
Wolter-I X-ray optics and an array of position-sensitive multi-pixel Silicon
Drift Detectors. To optimize the scientific payloads for operating properly in
orbit and performing the observations with high sensitivities, this work
performs an in-orbit background simulation of a type-B CATCH satellite using
the Geant4 toolkit. It shows that the persistent background is dominated by the
cosmic X-ray diffuse background and the cosmic-ray protons. The dynamic
background is also estimated considering trapped charged particles in the
radiation belts and low-energy charged particles near the geomagnetic equator,
which is dominated by the incident electrons outside the aperture. The
simulated persistent background within the focal spot is used to estimate the
observation sensitivity, i.e. 4.2210 erg cm s
with an exposure of 10 s and a Crab-like source spectrum, which can be
utilized further to optimize the shielding design. The simulated in-orbit
background also suggests that the magnetic diverter just underneath the optics
may be unnecessary in this kind of micro-satellites, because the dynamic
background induced by charged particles outside the aperture is around 3 orders
of magnitude larger than that inside the aperture.Comment: 24 pages, 13 figures, 7 tables, accepted for publication in
Experimental Astronom
Global climate forcing of aerosols embodied in international trade
International trade separates regions consuming goods and services from regions where goods and related aerosol pollution are produced. Yet the role of trade in aerosol climate forcing attributed to different regions has never been quantified. Here, we contrast the direct radiative forcing of aerosols related to regionsâ consumption of goods and services against the forcing due to emissions produced in each region. Aerosols assessed include black carbon, primary organic aerosol, and secondary inorganic aerosols, including sulfate, nitrate and ammonium. We find that global aerosol radiative forcing due to emissions produced in East Asia is much stronger than the forcing related to goods and services ultimately consumed in that region because of its large net export of emissions-intensive goods. The opposite is true for net importers such as Western Europe and North America: global radiative forcing related to consumption is much greater than the forcing due to emissions produced in these regions. Overall, trade is associated with a shift of radiative forcing from net importing to net exporting regions. Compared to greenhouse gases such as carbon dioxide, the short atmospheric lifetimes of aerosols cause large localized differences between consumption- and production-related radiative forcing. International efforts to reduce emissions in the exporting countries will help alleviate trade-related climate and health impacts of aerosols while lowering global emissions
Transboundary health impacts of transported global air pollution and international trade
Millions of people die every year from diseases caused by exposure to outdoor air pollution1, 2, 3, 4, 5. Some studies have estimated premature mortality related to local sources of air pollution6, 7, but local air quality can also be affected by atmospheric transport of pollution from distant sources8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18. International trade is contributing to the globalization of emission and pollution as a result of the production of goods (and their associated emissions) in one region for consumption in another region14, 19, 20, 21, 22. The effects of international trade on air pollutant emissions23, air quality14 and health24 have been investigated regionally, but a combined, global assessment of the health impacts related to international trade and the transport of atmospheric air pollution is lacking. Here we combine four global models to estimate premature mortality caused by fine particulate matter (PM2.5) pollution as a result of atmospheric transport and the production and consumption of goods and services in different world regions. We find that, of the 3.45 million premature deaths related to PM2.5 pollution in 2007 worldwide, about 12 per cent (411,100 deaths) were related to air pollutants emitted in a region of the world other than that in which the death occurred, and about 22 per cent (762,400 deaths) were associated with goods and services produced in one region for consumption in another. For example, PM2.5 pollution produced in China in 2007 is linked to more than 64,800 premature deaths in regions other than China, including more than 3,100 premature deaths in western Europe and the USA; on the other hand, consumption in western Europe and the USA is linked to more than 108,600 premature deaths in China. Our results reveal that the transboundary health impacts of PM2.5 pollution associated with international trade are greater than those associated with long-distance atmospheric pollutant transport
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