1,016 research outputs found

    Climatological estimates of precipitation and evaporation over the Baltic Proper based on COADS

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    The management of distal ulnar fractures in adults: a review of the literature and recommendations for treatment

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    The distal ulna represents the fixed point around which the radius and the hand acts in daily living. The significance of distal ulnar fractures is often not appreciated and often results in inadequate treatment in comparison to its larger counterpart; the radius. There is little guidance in the current literature as how to manage these fractures and their associated injuries. This paper aims to critically review the current literature and combine it with treatment suggestions based on the experience of the authors to help guide investigation and management of these often complex injuries

    Air entrainment mechanisms from artificial supercavities: Insight based on numerical simulations

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    Using multiphase computational simulations based on the Navier-Stokes equations, we examine the internal gaseous flows of artificially ventilated supercavities. These simulations indicate that air shear layers that develop on the cavity-wall (the air-liquid interface surrounding the cavity) are an important mechanism of air entrainment. This corroborates previous theory developed for toroidal cavities, and indicates that similar mechanisms occur in twin-vortex cavities and cavities closing on bodies. The importance of these shear layers on the cavity behavior potentially impacts computational simulations, experiments, and design-level models. Lastly, a more inclusive, semi-empirical air entrainment model is presented that attempts to accommodate the observed processes.http://deepblue.lib.umich.edu/bitstream/2027.42/84310/1/CAV2009-final136.pd

    An examination of thermal modeling affects to the numerical prediction of large-scale cavitating fluid flow

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    The importance of modeling thermal effects in cavitatingfluid is examined in the context of computational fluid dynamics. Simulations of cavitation in water are used to study the effects of thermal versus and pressure variations in the fluid properties, and their impact on predictions. These studies are extended to evaluate energyconserving approaches compared to isothermal ones, to assess the underlying thermal models influence on the predicted cavities occurring in water. Results indicate that the thermal effects remain important, but only for specific applications that need high-frequency phenomena from the numerical simulation. Low-frequency measures, needed for loading analysis, appear to be relatively insensitive to thermal effects. Lastly, various thermally driven cavitation problems requiring energy-equation conservation are presented to display applications requiring such a formulation.http://deepblue.lib.umich.edu/bitstream/2027.42/84311/1/CAV2009-final137.pd

    Small-angle neutron scattering (SANS) characterization of 13.5 Cr oxide dispersion strengthened ferritic steel for fusion applications

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    Small-angle neutron scattering (SANS) has been utilized for micro-structural investigation on laboratory heats of oxide dispersion strengthened (ODS) 13.5 Cr wt % ferritic steel, with 0.3 wt% Y2_{2}O3_{3} and with variable Ti and W contents. The results show that increasing the Ti content from 0.2 to 0.4 wt% a distribution of nano-clusters develops, tentatively identified as Y2_{2}Ti2_{2}O7_{7}, with average radii as small as 6.5 Å and volume fractions increasing from 0.021 to 0.032. The measured SANS cross-sections show also the growth of much larger defects, possibly Cr oxides. Furthermore, the ratio of magnetic to nuclear SANS components shows that the defect composition varies both with their size and with the Ti and the W content. These results are in qualitative agreement with transmission electron microscopy (TEM) observations, showing a striking influence of Ti addition on particle size refinement. However, while TEM is limited in statistics and minimum observable size of the Ti-rich nano-clusters, the defect distributions obtained by these SANS measurements provide complementary information useful for morphological characterization of the micro-structure in the investigated material
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