99 research outputs found
Surgical Aspects of Dissecting Aortic Aneurysms
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66511/2/10.1177_000331975400500313.pd
Dynamic multi-phase partitioning of decamethylcyclopentasiloxane (D5) in river water
The behaviour of decamethylcyclopentasiloxane (D5) in river water was evaluated
by measuring concentration changes in open beakers. Effective values for the
partition coefficient between organic carbon and water (K) were derived by
least-squares optimisation of a dynamic model which accounted for partitioning
between the sorbed and dissolved phases of D5, and for losses via volatilisation
and hydrolysis. Partial mass transfer coefficients for volatilisation were
derived from model fits to controls containing deionised water. Effective values
of log (K) were between 5.8 and 6.33 (mean 6.16). These figures are higher than
some other experimentally-derived values but much lower than those estimated
from the octanol: water partition coefficient using single-parameter linear free
energy relationships (LFERs). A poly-parameter LFER gave a predicted log (K) of
5.5. Differences in partitioning are believed to be due to the nature of the
organic matter present. The new value for effective K was employed in a simple
model of D5 behaviour in rivers to ascertain the extent to which a higher
affinity for organic carbon would depress volatility. The results suggest that
despite the revised K value, volatilisation of D5 remains a significant removal
mechanism in surface waters. © 2010 Elsevier Lt
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Turbulence in slurry pipe flow
The present state of knowledge of liquid-solid flows (slurries) is far behind than that for single phase flows. Very few geometries have been examined with a slurry and only with a limited variation of system parameters i.e. fluid viscosity, particle diameter, etc. This paper presents the first part of a study which examines the effects of the addition of a solid to the flow through a confined coaxial jet. Presented here will be the initial conditions for the jet which correspond to fully developed pipe flow. 6 refs., 9 figs
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