4,628 research outputs found
A comparison of plastic collapse and limit loads for single mitred pipe bends under in-plane bending
This paper presents a comparison of the plastic collapse loads from experimental in-plane bending tests on three 90 degree single un-reinforced mitred pipe bends, with the results from various 3D solid finite element models. The bending load applied reduced the bend angle and in turn, the resulting cross-sectional ovalisation led to a recognised weakening mechanism, which is only observable by testing or by including large displacement effects in the plastic finite element solution. A small displacement limit solution with an elastic-perfectly-plastic material model overestimated the collapse load by 40%. The plastic collapse finite element solution produced excellent agreement with experiment
Using limb darkening to measure fundamental parameters of stars
Context. Limb darkening is an important tool for understanding stellar
atmospheres, but most observations measuring limb darkening assume various
parameterizations that yield no significant information about the structure of
stellar atmospheres. Aims. We use a specific limb-darkening relation to study
how the best-fit coefficients relate to fundamental stellar parameters from
spherically symmetric model stellar atmospheres. Methods. Using a grid of
spherically symmetric Atlas model atmospheres, we compute limb-darkening
coefficients, and develop a novel method to predict fundamental stellar
parameters. Results. We find our proposed method predicts the mass of stellar
atmosphere models given only the radius and limb-darkening coefficients,
suggesting that microlensing, interferometric, transit and eclipse observations
can constrain stellar masses. Conclusions. This novel method demonstrates that
limb-darkening parameterizations contain important information about the
structure of stellar atmospheres, with the potential to be a valuable tool for
measuring stellar masses.Comment: 8 pages, 6 figures, 2 tables, A&A accepte
A mathematical approach to depuration
Two equations can be written to describe the change in bacterial concentrations in the shellfish and the water in depuration units. Analytical solutions of these equations for special conditions and numerical solutions for general conditions indicate that there will always be an initial, rapid decrease in bacteria in the oysters during depuration. With suitable flow rates and loading rates, the die off will be exponential and several orders of magnitude reduction can be achieved within 72 hours. Both very low flow rates and very low loading rates increase the residence time of water in the tank, and therefore depuration will occur slowly after about 24 hours. In addition, the bacterial levels at 72 hours may be quite high for the case of very low flow rates. Further improvements and verification of the model are desired, but use of the model can aid in the design and operation of depuration plants now
Have computers, will travel: providing on-site library instruction in rural health facilities using a portable computer lab
The Saskatchewan Health Information Resources Partnership (SHIRP)provides library instruction to Saskatchewan's health care practitioners and students on placement in health care facilities as part of its mission to provide province-wide access to evidence-based health library resources. A portable computer lab was assembled in
2007 to provide hands-on training in rural health facilities that do not have computer labs of their own. Aside from some minor inconveniences, the introduction and operation of the portable lab has gone smoothly. The lab has been well received by SHIRP patrons and continues to be an essential part of SHIRP outreach
The Drowned Forest of the Columbia Gorge
"Early travelers mention the great numbers [of trees], and vast multitude of huge trunks which were described by ten writers as standing in the water, ten, fifteen or twenty feet deep. They were far out on each side, and canoes had to wind in and out among them as when one walks through a forest.
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