318 research outputs found
Partitioning of U, Th and K Between Metal, Sulfide and Silicate, Insights into the Volatile-Content of Mercury
During the early stages of the Solar System formation, especially during the T-Tauri phase, the Sun emitted strong solar winds, which are thought to have expelled a portion of the volatile elements from the inner solar system. It is therefore usually believed that the volatile depletion of a planet is correlated with its proximity to the Sun. This trend was supported by the K/Th and K/U ratios of Venus, the Earth, and Mars. Prior to the MESSENGER mission, it was expected that Mercury is the most volatile-depleted planet. However, the Gamma Ray Spectrometer of MESSENGER spacecraft revealed elevated K/U and K/Th ratios for the surface of Mercury, much higher than previous expectations. It is possible that the K/Th and K/U ratios on the surface are not a reliable gauge of the bulk volatile content of Mercury. Mercury is enriched in sulfur and is the most reduced of the terrestrial planets, with oxygen fugacity (fO2) between IW-6.3 and IW-2.6 log units. At these particular compositions, U, Th and K behave differently and can become more siderophile or chalcophile. If significant amounts of U and Th are sequestered in the core, the apparent K/U and K/Th ratios measured on the surface may not represent the volatile budget of the whole planet. An accurate determination of the partitioning of these elements between silicate, metal, and sulfide phases under Mercurian conditions is therefore essential to better constrain Mercury's volatile content and assess planetary formation models
Assessment of a self-reported Drinks Diary for the estimation of drinks intake by care home residents: Fluid Intake Study in the Elderly (FISE)
Objectives: We evaluated the accuracy of a newly developed self-completed Drinks Diary in care home residents and compared it with direct observation and fluid intake charts. Design: Observational study. Setting: Residential care homes in Norfolk, UK. Participants: 22 elderly people (18 women, mean age 86.6 years SD 8.6, 12 with MMSE scores <27). Measurements: Participants recorded their own drinks intake over 24 hours using the Drinks Diary while care staff used the homes’ usual fluid intake chart to record drinks intake. These records were compared with drinks intake assessed by researcher direct observation (reference method), during waking hours (6am to 10pm), while drinks taken from 10pm to 6am were self-reported and checked with staff. Results: Drinks intake assessed by the Drinks Diary was highly correlated with researcher direct observation (Pearson correlation coefficient r=0.93, p<0.001, mean difference -163ml/day) while few staff-completed fluid charts were returned and correlation was low (r=0.122, p=0.818, mean difference 702ml/day). The Drinks Diary classified 19 of 22 participants correctly as drinking enough or not using both the European Food Safety Authority and US recommendations. Conclusion: The Drinks Diary estimate of drinks intake was comparable with direct observation and more accurate (and reliably completed) than staff records. The Drinks Diary can provide a reliable estimate of drinks intake in elderly care home residents physically and cognitively able to complete it. It may be useful for researchers, care staff and practitioners needing to monitor drinks intake of elderly people, to help them avoid dehydration
Crew Resource Management for Automated Teammates (CRM-A)
Crew Resource Management (CRM) is the application of human factors knowledge and skills to ensure that teams make effective use of all resources. This includes ensuring that pilots bring in opinions of other teammates and utilize their unique capabilities. CRM was originally developed 40 years ago in response to a number of airline accidents in which the crew was found to be at fault. The goal was to improve teamwork among airline cockpit crews. The notion of "team" was later expanded to include cabin crew and ground resources. CRM has also been adopted by other industries, most notably medicine. Automation research now finds itself faced with similar issues to those faced by aviation 40 years ago: how to create a more robust system by making full use of both the automation and its human operators. With advances in machine intelligence, processing speed and cheap and plentiful memory, automation has advanced to the point that it can and should be treated as a teammate to fully take advantage of its capabilities and contributions to the system. This area of research is known as Human-Autonomy Teaming (HAT). Research on HAT has identified reusable patterns that can be applied in a wide range of applications. These patterns include features such as bi-directional communication and working agreements. This paper will explore the synergies between CRM and HAT. We believe that HAT research has much to learn from CRM and that there are benefits to expanding CRM to cover automation
Information Display System for Atypical Flight Phase
Method and system for displaying information on one or more aircraft flights, where at least one flight is determined to have at least one atypical flight phase according to specified criteria. A flight parameter trace for an atypical phase is displayed and compared graphically with a group of traces, for the corresponding flight phase and corresponding flight parameter, for flights that do not manifest atypicality in that phase
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Fabrication of non-fertile and evolutionary mixed oxide fuels
Non-fertile and evolutionary mixed oxide (EMOX) fuels for light water reactors have been fabricated using the solid-state reaction method. Specifically, the non-fertile fuel form fabricated for this study was a PuO{sub 2}-ZrO{sub 2}-CaO-Er{sub 2}O{sub 3}composition. Weapons-grade plutonium served as the source of PuO{sub 2}. The non-fertile fuel offers the key advantage of the {open_quotes}deep burn{close_quotes} capability for a once-through cycle. The non-fertile fuel achieves this performance through the absence of uranium, which breeds plutonium, in the fuel composition. An EMOX fuel form with a composition of PuO{sub 2}-UO{sub 2}-ZrO{sub 2}-CaO was also fabricated using weapons-grade plutonium and depleted uranium. The EMOX fuel concept allows for greater plutonium destruction as compared to standard MOX fuel and provides a licensing path forward towards eventual implementation of non-fertile fuels in light water reactors. This paper summarizes the ongoing activities and past accomplishments for the fabrication of non-fertile and EMOX fuel pellets. 2 figs
The image after Strathern:Art and persuasive relationality in India's sanguinary politics
Publicly-enacted blood extractions (principally blood donation events and petitions or paintings in blood) in mass Indian political contexts (for instance, protest or political memorial events and election rallies) are a noteworthy present-day form of political enunciation in India, for such extractions – made to speak as and on behalf of political subject positions – are intensely communicative. Somewhat akin to the transformative fasts undertaken by Gandhi, such blood extractions seek to persuade from the moral high ground of political asceticism. This essay seeks to shed light on how and why these extractions have become such a means, with a particular focus on blood-based portraiture. What makes such portraits – chiefly of politicians and ‘freedom fighter’ martyrs – interesting from a Strathernian point of view is their immanent persuasive relationality. The insights of Strathern can help us to explicate these objects’ dynamic relational features, while reciprocally, the portraits may help us to illuminate and clarify the very particular and interesting nature of the way Strathern treats (and creates) images
Micromechanical Properties of Injection-Molded Starch–Wood Particle Composites
The micromechanical properties of injection molded starch–wood particle composites were investigated as a function of particle content and humidity conditions.
The composite materials were characterized by scanning electron microscopy and X-ray diffraction methods. The microhardness
of the composites was shown to increase notably with the concentration of the wood particles. In addition,creep behavior under the indenter and temperature dependence
were evaluated in terms of the independent contribution of the starch matrix and the wood microparticles to the hardness value. The influence of drying time on the density
and weight uptake of the injection-molded composites was highlighted. The results revealed the role of the mechanism of water evaporation, showing that the dependence of water uptake and temperature was greater for the starch–wood composites than for the pure starch sample. Experiments performed during the drying process at 70°C indicated that
the wood in the starch composites did not prevent water loss from the samples.Peer reviewe
Transition Metal Complexes of Dibenzyl Tetraazamacrocycles
Tetraazamacrocycles, cyclic molecules with four nitrogen atoms, have long been known to produce highly stable transition metal complexes. Cross-bridging such molecules with 2-carbon chains has been shown to enhance the stability of these complexes even further, providing enough stability to use the resulting compounds in applications as diverse and demanding as aqueous, green oxidation catalysis all the way to drug molecules injected into humans. Although the stability of these compounds is believed to result from the increased rigidity and topological complexity imparted by the cross-bridge, there is insufficient experimental data to exclude other causes. In this study, standard organic and inorganic synthetic methods were used to produce unbridged dibenzyl tetraazamacrocycle analogues of known cross-bridged tetraazamacrocycles and their transition metal complexes to allow direct comparison of molecules identical except for the cross-bridge. The syntheses of the known tetraazamacrocycles and the novel transition metal complexes were successful with high yields and purity. Initial chemical characterization of the complexes by UV-Visible spectroscopy and cyclic voltammetry shows little difference in electronic properties from bridged versions. Direct comparison studies of the unbridged and bridged compounds’ stabilities remain to be carried out and will shed light on the importance of the cross-bridge to complex robustness
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SHOCK INITIATION EXPERIMENTS ON PBX 9501 EXPLOSIVE AT PRESSURES BELOW 3 GPa WITH ASSOCIATED IGNITION AND GROWTH MODELING
Shock initiation experiments on the explosive PBX 9501 (95% HMX, 2.5% estane, and 2.5% nitroplasticizer by weight) were performed at pressures below 3 GPa to obtain in-situ pressure gauge data, run-distance-to-detonation thresholds, and Ignition and Growth modeling parameters. Propellant driven gas guns (101 mm and 155 mm) were utilized to initiate the PBX 9501 explosive with manganin piezoresistive pressure gauge packages placed between sample slices. The run-distance-to-detonation points on the Pop-plot for these experiments showed agreement with previously published data and Ignition and Growth modeling parameters were obtained with a good fit to the experimental data. This parameter set will allow accurate code predictions to be calculated for safety scenarios in the low-pressure regime (below 3 GPa) involving PBX 9501 explosive
Converting houses into churches: The mobility, fission, and sacred networks of evangelical house churches in Sri Lanka
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