920 resultados para Mixing.
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Includes index.
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Includes index.
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Includes indexes.
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"May 1968."
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"April 1968."
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"April 1968."
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Thesis (Master's)--University of Washington, 2016-06
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Thesis (Ph.D.)--University of Washington, 2016-06
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These are data of eddy covariance flux measurements of formic acid (HCOOH), performed by a chemical ionization mass spectrometer (CIMS) over a boreal forest canopy in Hyytiälä, Finland, in spring/summer 2014. Results from the 1-D chemical transport model runs using SOSAA (Simulate Organic vapours, Sulphuric Acid and Aerosols) are included as well. The data accompany a submission of a manuscript to Geophysical Research Letters for consideration for publication (Schobesberger et al.).
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Samples of the cyanobacterium Microcystis aeruginosa from a small pond were used in laboratory experiments with a grid-stirred tank to quantify the effect of turbulent mixing on colony size. Turbulent dissipation in the tank was varied from 10(-9) m(2) s(-3) to 10(-4) m(2) s(-3), covering the range of turbulence intensities experienced by M. aeruginosa colonies in the field and exceeding the maximum dissipation by two orders of magnitude. Large colonies broke up into smaller colonies during the experiments; the mass fraction of colonies with diameter less than 200 mum increased over time. Colony disaggregation was observed to increase with turbulent dissipation. The maximum stable colony diameter across all experiments was in the range 220-420 mum. The overall change in size distribution during the experiments was relatively small, and the colony size distribution remained very broad throughout the experiments. Since colony size affects migration velocity, susceptibility to grazing and surface area to volume ratios, more work is needed to determine how to best represent this broad size distribution when modelling M. aeruginosa populations.
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Mitarai [Phys. Fluids 17, 047101 (2005)] compared turbulent combustion models against homogeneous direct numerical simulations with extinction/recognition phenomena. The recently suggested multiple mapping conditioning (MMC) was not considered and is simulated here for the same case with favorable results. Implementation issues crucial for successful MMC simulations are also discussed.
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Stirred Mills are becoming increasingly used for fine and ultra-fine grinding. This technology is still poorly understood when used in the mineral processing context. This makes process optimisation of such devices problematic. 3D DEM simulations of the flow of grinding media in pilot scale tower mills and pin mills are carried out in order to investigate the relative performance of these stirred mills. In the first part of this paper, media flow patterns and energy absorption rates and distributions were analysed to provide a good understanding of the media flow and the collisional environment in these mills. In this second part we analyse steady state coherent flow structures, liner stress and wear by impact and abrasion. We also examine mixing and transport efficiency. Together these provide a comprehensive understanding of all the key processes operating in these mills and a clear understanding of the relative performance issues. (C) 2006 Elsevier Ltd. All rights reserved.
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Complete rare earth element (except Eu) and Y concentrations from the estuarine mixing zone (salinity =0.2 to 33) of Elimbah Creek, Queensland, Australia, were measured by quadrupole ICP-MS without preconcentration. High sampling density in the low salinity regime along with high quality data allow accurate tracing of the development of the typical marine rare earth element anomalies as well as Y/Ho fractionation. Over the entire estuary, the rare earth elements are strongly removed relative to a freshwater endmember (60-80% removal). This large overall removal occurs despite a strong remineralisation peak (190% for La, 130% for Y relative to the freshwater endmember) in the mid-salinity zone. Removal and remineralisation are accompanied by fractionation of the original (freshwater) rare earth element pattern, resulting in light rare earth element depletion. Estuarine fractionation generates a large positive La anomaly and a superchondritic Y/Ho ratio. Conversely, we observe no evidence to support the generation of the negative Ce anomaly in the estuary. With the exception of Ce, the typical marine rare earth element features can thus be attributed to estuarine mixing processes. The persistence of these features in hydrogenous sediments for at least 3.71 Ga highlights the importance of estuarine processes for marine chemistry on geological timescales. (c) 2005 Elsevier B.V. All rights reserved.