41,686 research outputs found
Thermodynamic property measurements in reflected shock air plasmas at 12,000 - 16,000 K
Reflected shock air plasma thermodynamic properties at 12,000 to 16,000 deg
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Mechanical Properties and Biological Responses of Bioactive Glass Ceramics Processed using Indirect SLS
This paper will report on research which aims to generate bone replacement components by
processing bioactive glass-ceramic powders using indirect selective laser sintering. The indirect
SLS route has been chosen as it offers the ability to tailor the shape of the implant to the
implantation site, and two bioactive glass ceramic materials have been processed through this
route: apatite-mullite and apatite-wollostanite. The results of bend tests, to investigate
mechanical properties, and in vitro and in vivo experiments to investigate biological responses of
the materials will be reported, and the suitability of completed components for implant will be
assessed.Mechanical Engineerin
Chemical abundance study of two strongly s-process enriched post-AGB stars in the LMC: J051213.81-693537.1 and J051848.86-700246.9
Context: This paper is part of a larger project in which we study the
chemical abundances of extra-galactic post-AGB stars with the ultimate goal of
improving our knowledge of the poorly understood AGB third dredge-up mixing
processes and s-process nucleosynthesis. Aims: In this paper, we study two
carefully selected post-AGB stars in the LMC. The combination of favourable
atmospheric parameters for detailed abundance studies and their known distances
make these objects ideal probes of the internal AGB third dredge-up and
s-process nucleosynthesis in that they provide observational constraints for
theoretical AGB models. Methods: We use high-resolution optical UVES spectra to
determine accurate stellar parameters and perform detailed elemental abundance
studies. Additionally, we use available photometric data to construct SEDs for
reddening and luminosity determinations. We then estimate initial masses from
theoretical post-AGB tracks. Results: Both stars show extreme s-process
enrichment associated with relatively low C/O ratios of about 1.3. We could
only derive upper limits of the lead (Pb) abundance which indicate no strong Pb
overabundances with respect to other s-elements. Comparison with theoretical
post-AGB evolutionary tracks in the HR-diagram reveals that both stars have low
initial masses between 1.0 and 1.5 Msun. Conclusion: This study adds to the
results obtained so far on a very limited number of s-process enriched post-AGB
stars in the Magellanic Clouds. We find an increasing discrepancy between
observed and predicted Pb abundances towards lower metallicities for all
studied Magellanic Cloud post-AGB stars found so far, as well as moderate C/O
ratios. We find that all s-process rich post-AGB stars in the LMC and SMC
studied so far, cluster in the same region of the HR-diagram and are associated
with low-mass stars with a low metallicity on average.Comment: 11 pages, 14 figure
Chemical abundance study of two strongly s-process enriched post-AGB stars in the LMC: J051213.81-693537.1 and J051848.86-700246.9
Context: This paper is part of a larger project in which we study the
chemical abundances of extra-galactic post-AGB stars with the ultimate goal of
improving our knowledge of the poorly understood AGB third dredge-up mixing
processes and s-process nucleosynthesis. Aims: In this paper, we study two
carefully selected post-AGB stars in the LMC. The combination of favourable
atmospheric parameters for detailed abundance studies and their known distances
make these objects ideal probes of the internal AGB third dredge-up and
s-process nucleosynthesis in that they provide observational constraints for
theoretical AGB models. Methods: We use high-resolution optical UVES spectra to
determine accurate stellar parameters and perform detailed elemental abundance
studies. Additionally, we use available photometric data to construct SEDs for
reddening and luminosity determinations. We then estimate initial masses from
theoretical post-AGB tracks. Results: Both stars show extreme s-process
enrichment associated with relatively low C/O ratios of about 1.3. We could
only derive upper limits of the lead (Pb) abundance which indicate no strong Pb
overabundances with respect to other s-elements. Comparison with theoretical
post-AGB evolutionary tracks in the HR-diagram reveals that both stars have low
initial masses between 1.0 and 1.5 Msun. Conclusion: This study adds to the
results obtained so far on a very limited number of s-process enriched post-AGB
stars in the Magellanic Clouds. We find an increasing discrepancy between
observed and predicted Pb abundances towards lower metallicities for all
studied Magellanic Cloud post-AGB stars found so far, as well as moderate C/O
ratios. We find that all s-process rich post-AGB stars in the LMC and SMC
studied so far, cluster in the same region of the HR-diagram and are associated
with low-mass stars with a low metallicity on average.Comment: 11 pages, 14 figure
Theoretical and experimental investigation of supersonic aerodynamic characteristics of a twin-fuselage concept
A theoretical and experimental investigation has been conducted to evaluate the fundamental supersonic aerodynamic characteristics of a generic twin-body model at a Mach number of 2.70. Results show that existing aerodynamic prediction methods are adequate for making preliminary aerodynamic estimates
Mission impossible? Identity based incompatibilities amongst academic job roles relate to wellbeing and turnover.
Academic staff experience high levels of work-related stress and poor mental health. As a result, many institutions face high staff turnover. These outcomes may be driven by the complexity and, at times, apparently oppositional objectives academics need to meet around research and teaching. These factors may present both practical and social identity-based incompatibilities. The current study tested the role of these incompatibilities upon mental well-being and turnover. A sample of 141 UK resident academics completed scales measuring levels of social identification with being an academic, an educator and a researcher, identity based and practical incompatibility, mental health, experience of the workplace and turnover intention. No direct links were found between practical incompatibility and outcomes. However, higher identity incompatibility was related to poorer mental health. Identity incompatibility was also related to turnover intention, mediated by both mental health and workplace experience. Contrary to predictions, these effects were not moderated by identity difference or identity strength. The current findings present evidence that role-based incompatibilities have both practical and identity-based foundations and highlight important caveats to the benefits of multiple identities on well-being observed in other domains. The findings also suggest practical steps through which complex occupational roles can be best structured to improve mental health and reduce turnover
Comparison of Allen Carr's Easyway programme with a specialist behavioural and pharmacological smoking cessation support service: a randomized controlled trial.
BACKGROUND AND AIMS: A combination of behavioural and pharmacological support is judged to be the optimal approach for assisting smoking cessation. Allen Carr's Easyway (ACE) is a single-session pharmacotherapy-free programme that has been in operation internationally for 38 years. We compared the effectiveness of ACE with specialist behavioural and pharmacological support delivered to the national standard in England. DESIGN: A two-arm, parallel-group, single-blind, randomized controlled trial. SETTING: London, UK, between February 2017 and May 2018. PARTICIPANTS: A total of 620 participants (310 in ACE and 310 in the combined behavioural and pharmacological support condition) were included in the analysis. Adult (≥ 18 years) smokers wanting to quit were randomized in a 1 : 1 ratio. Mean age for the total sample was 40.8 years, with 53.4% being male. Participant baseline characteristics (ethnicity, educational level, number of previous quit attempts, nicotine dependence) were evenly balanced between treatment groups. INTERVENTION AND COMPARATOR: The intervention was the ACE method of stopping smoking. This centres on a 4.5-6-hour session of group-based support, alongside subsequent text messages and top-up sessions if needed. It aims to make it easy to stop smoking by convincing smokers that smoking provides no benefits for them. The comparator was a specialist stop smoking service (SSS) providing behavioural and pharmacological support in accordance with national standards. MEASUREMENTS: The primary outcome was self-reported continuous abstinence for 26 weeks from the quit/quit re-set date verified by exhaled breath carbon monoxide measurement < 10 parts per million (p.p.m.). Primary analysis was by intention to treat. Secondary outcomes were: use of pharmacotherapy, adverse events and continuous abstinence up to 4 and 12 weeks. FINDINGS: A total of 468 participants attended treatment (255 ACE versus 213 SSS, P < 0.05). Of those who did attend treatment, 100 completed 6-month measures (23.7% ACE versus 20.7% SSS). Continuous abstinence to 26 weeks was 19.4% (60 of 310) in the ACE intervention and 14.8% (46 of 310) in the SSS intervention [risk difference for ACE versus SSS 4.5% (95% confidence interval (CI) = -1.4 to 10.4%, odds ratio (OR) = 1.38)]. The Bayes factor for superiority of the ACE condition was 1.24. CONCLUSION: There was no clear evidence of a difference in the efficacies of the Allen Carr's Easyway (ACE) and specialist smoking cessation support involving behavioural support and pharmacotherapy
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