1,447 research outputs found

    Investigation of the flaw growth characteristics of 6Al-4V titanium used in the Apollo spacecraft pressure vessels

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    Failure analysis of flaw growth characteristics of 6Al-4V titanium forgings used in Apollo spacecraft propellant tank

    Fracture control of metallic pressure vessels. NASA space vehicle design criteria, structures

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    Design criteria for fracture optimization of metallic pressure vessel

    Investigation of plane-strain flaw growth in thick-walled tanks Final report, 26 Jun. 1964 - 26 Oct. 1965

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    Flaw growth rates and fracture toughness data for materials used in thick walled cylindrical tank

    Investigation of crack growth threshold of Inconel 718 exposed to high pressure oxygen Final report 24 Apr. - 25 May 1970

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    Crack growth threshold investigation of Inconel 718 exposed to high pressure oxyge

    Social Determinants of Smoke Exposure During Pregnancy: Findings From Waves 1 & 2 of the Population Assessment of Tobacco and Health (PATH) Study

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    Maternal smoking during pregnancy (MSDP) and secondhand smoke (SHS) exposure are associated with a myriad of negative health effects for both mother and child. However, less is known regarding social determinants for SHS exposure, which may differ from those of maternal smoking during pregnancy (MSDP). To identify social determinants for SHS exposure only, MSDP only, and MSDP and SHS exposure, data were obtained from all pregnant women (18–54 years; N = 726) in waves 1 and 2 of the Population Assessment of Tobacco and Health Study (2014–2015). Multiple logistic regressions were conducted using SAS 9.4. Smoke exposure during pregnancy was common; 23.0% reported SHS exposure only, 6.1% reported MSDP only, and 11.8% reported both SHS exposure and MSDP. Results demonstrate that relationships between smoke exposure during pregnancy and social determinants vary by type of exposure. Women at risk for any smoke exposure during pregnancy include those who are unmarried and allow the use of combustible tobacco products within the home. Those who are at higher risk for SHS exposure include those who are younger in age, and those who are earlier in their pregnancy. Those who are at higher risk for maternal smoking include those with fair/poor mental health status and those who believe that others\u27 view tobacco use more positively. These results suggest the need for implementing more comprehensive policies that promote smoke-free environments. Implementing these strategies have the potential to improve maternal and fetal health outcomes associated with tobacco smoke exposure

    Finding the Needles in the Haystacks: High-Fidelity Models of the Modern and Archean Solar System for Simulating Exoplanet Observations

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    We present two state-of-the-art models of the solar system, one corresponding to the present day and one to the Archean Eon 3.5 billion years ago. Each model contains spatial and spectral information for the star, the planets, and the interplanetary dust, extending to 50 AU from the sun and covering the wavelength range 0.3 to 2.5 micron. In addition, we created a spectral image cube representative of the astronomical backgrounds that will be seen behind deep observations of extrasolar planetary systems, including galaxies and Milky Way stars. These models are intended as inputs to high-fidelity simulations of direct observations of exoplanetary systems using telescopes equipped with high-contrast capability. They will help improve the realism of observation and instrument parameters that are required inputs to statistical observatory yield calculations, as well as guide development of post-processing algorithms for telescopes capable of directly imaging Earth-like planets.Comment: Accepted for publication in PAS

    Sustainable Development Goal 3

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    Sustainable Development Goals (SDGs) aim to develop a better and sustainable future for the world and the goals are part of an action plan to address poverty, hunger, health, gender equity and various pressing world issues. One of these goals looks at health and wellness. Ageing populations have become a crucial issue worldwide and this short monograph explores ageing and how the consequences of an ageing population may affect our health care system through the case study on Hong Kong's population. The book looks at several critical health issues related to ageing. The elderly, particularly those with low socioeconomic status, rely more on the acute-centric care rather than primary care. The book suggests that secondary care service may only be effective to limited extent as a healthcare measure and an optimum health care system should be one that focuses on primary care. The authors put forth a compelling argument for disease prevention and screening schemes and explain how they are more cost-effective and beneficial to the society and the system. This thoughtful book will provide beneficial insights into the relationship of ageing and sustainable development goals in the context of health and wellness for policy makers and healthcare professionals

    Interactions of local climatic, biotic and hydrogeochemical processes facilitate phosphorus dynamics along an Everglades forest-marsh gradient

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    Ecosystem nutrient cycling is often complex because nutrient dynamics within and between systems are mediated by the interaction of biological and geochemical conditions operating at different temporal and spatial scales. Vegetated patches in semiarid and wetland landscapes have been shown to exemplify some of these patterns and processes. We investigated biological and geochemical factors suggested to contribute to phosphorus (P) movement and availability along a forest-marsh gradient in an Everglades tree island. Our study illustrated processes that are consistent with the chemohydrodynamic nutrient (CHNT) hypothesis and the trigger-transfer, pulse-reserve (TTPR) model developed for semiarid systems. Comparison with the TTPR model was constructive as it elaborated several significant patterns and processes of the tree island ecosystem including: (1) concentration of the limiting resource (P) in the source patch (High Head which constitutes the reserve) compared with the resource-poor landscape, (2) soil zone calcite precipitation requiring strong seasonality for evapotranspiration to promote conditions for secondary soil development and calcium phosphate reprecipitation, (3) rewetting of previously dry soils by early wet season precipitation events, and (4) antecedent conditions of the source patch, including landscape position that modulated the effect of the precipitation trigger. Thus, our study showed how water availability drives soil water P dynamics and, potentially, stability of mineral soil P in this tree island ecosystem. In landscapes with extensive water management, these processes can be asynchronous with the seasonality of hydrologic dynamics, tipping the balance between a sink and source of a limiting nutrient
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