Settling progressive

J. Y. Oldshiie, Chemical Engineering Progress, Mixing of Slurries Near the Ultimate Settled Solids Concentration, 77(5) 95-98 (1981). 

Nonstirred ARC runs may give answers that do not adequately duphcate plant results when there are reactants that may settle out or that require mixing for the reaction to be carried out (DeHaven and Dietsche, The Dow Chemical Company, Pittsburgh, Calif., Catalyst Explosion A Case History, Plant (Operations Progress, April 1990). 

A fillet is a stagnant deposit of solids commonly found at the outside periphery of the bottom where it joins the tank. However, it could occur anywhere in the tank where the flow pattern is stagnant. Filleting is permitted, but no progressive fillet buildup is allowed. The reason is that it costs less to allow some solids to settle into fillets than to provide additional mixer horsepower to eliminate fillets. 

Wind transport. Wind-blown components are carried away over a more or less important distance as a function of wind velocity and particle size of the material. Wind speeds up till 6.5 m/sec transport dust and fine sand with a diameter of less than 0.25 mm sand grains up to 1 mm diameter are uplifted at wind speeds of 10 m/sec. At 20 m/sec also particles of 4-5 mm may be removed. Based on these physical laws, the transportation of coarse fragments, in casu the sand fraction, occurs over-relatively short distances from the deflation zones. These sand grains settle then in more or less continuous layers and either become progressively mixed with the underlying soil layers, or concentrate in dune formations. 

Pettyjohn, E.S. and Christiansen, E.B., Effect of particle shape on free-settling rates of isomeric particles, Chemical Engineering Progress, 44, pp. 157-72 (1948). 

The discussion so far relates to the motion of a single spherical particle in an effectively infinite expanse of fluid. If other particles are present in the neighbourhood of the sphere, the sedimentation velocity will be decreased, and the effect will become progressively more marked as the concentration is increased. There are three contributory factors. First, as the particles settle, they will displace an equal volume of fluid, and this gives rise to an upward flow of liquid. Secondly, the buoyancy force is influenced because the suspension has a higher density than the fluid. Finally, the flow pattern of the liquid relative to... 

When sediment settles onto the seafloor, a considerable amount of sediment is trapped between the grains. As discussed in Chapter 12.2.2, pelagic sediments can initially have equal parts of pore water mixed with the solids. As burial progresses, compaction causes the upward vertical advection of pore water, thereby reducing the water content of the... 

The Sponsor shall keep the NHS Trust and its legal advisors fully informed of the progress of any such claim or proceeding, will consult fully with the NHS Trust on the nature of any defence to be advanced and will not settle any such claim or proceeding without the written approval of the NHS Trust (such approval not to be unreasonably withheld). 

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