ABSTRACT Laboratory flume experiments were conducted in order to test the influence on sediment c... more ABSTRACT Laboratory flume experiments were conducted in order to test the influence on sediment credibility of varying densities of the tube-building polychaete worm Owenia fusi/ormis. Ex-periments were performed on isolated individuals, in order to measure approximate spatial limits of ...
ABSTRACT When measured or apparent yield stress of cohesive muds is assumed to reflect average pa... more ABSTRACT When measured or apparent yield stress of cohesive muds is assumed to reflect average particle-particle bond strength in network structures, critical bed shear stress required for grain-by-grain entrainment can be predicted from an analysis of the forces acting on component grains of geometrically-flat mud beds. Erosion resistance is then defined in terms of cohesive yield stress as well as nominal particle size, shape, relative density, and packing geometry. Predicted values of critical bed shear stress compare favorably with existing data from selected studies in which appropriate yield stress and hydrodynamic parameters have been reported.
Philosophical Transactions of the Royal Society B Biological Sciences, 1990
The concentration of fine 0(1pm) suspended sediment in deep-sea nepheloid layers is roughly 10 5 ... more The concentration of fine 0(1pm) suspended sediment in deep-sea nepheloid layers is roughly 10 5 particles cm -3 . Given this concentration, aggregation theory dictates that marine snow particles must remove fine particles at a rate of 3.5 x 10 -4 particles cm -3 s -1 for scavenging of small particles by large, fast-sinking ones to play a significant role in deposition from nepheloid layers. Assuming that one in every 10 fine particles that collide with a marine snow particle sticks to it, to achieve the above removal rate given a marine snow concentration of 10 -4 particles cm -3 requires contact efficiencies of 10 -1 to 10 -2 . Such values of contact efficiency are significantly larger than theoretical predictions of contact efficiency, but are supported by evidence from studies of radionuclide fluxes and particle size distributions. Discrepancies between inferred and predicted values of contact efficiency arise from differences in actual and model particle properties. Contact by direct interception potentially is enhanced by roughened particle surfaces and by wake capture. Wake capture is the process whereby fine particles are entrained in the recirculating eddies present behind settling particles with Reynolds numbers greater than one.
ABSTRACT Laboratory flume experiments were conducted in order to test the influence on sediment c... more ABSTRACT Laboratory flume experiments were conducted in order to test the influence on sediment credibility of varying densities of the tube-building polychaete worm Owenia fusi/ormis. Ex-periments were performed on isolated individuals, in order to measure approximate spatial limits of ...
ABSTRACT When measured or apparent yield stress of cohesive muds is assumed to reflect average pa... more ABSTRACT When measured or apparent yield stress of cohesive muds is assumed to reflect average particle-particle bond strength in network structures, critical bed shear stress required for grain-by-grain entrainment can be predicted from an analysis of the forces acting on component grains of geometrically-flat mud beds. Erosion resistance is then defined in terms of cohesive yield stress as well as nominal particle size, shape, relative density, and packing geometry. Predicted values of critical bed shear stress compare favorably with existing data from selected studies in which appropriate yield stress and hydrodynamic parameters have been reported.
Philosophical Transactions of the Royal Society B Biological Sciences, 1990
The concentration of fine 0(1pm) suspended sediment in deep-sea nepheloid layers is roughly 10 5 ... more The concentration of fine 0(1pm) suspended sediment in deep-sea nepheloid layers is roughly 10 5 particles cm -3 . Given this concentration, aggregation theory dictates that marine snow particles must remove fine particles at a rate of 3.5 x 10 -4 particles cm -3 s -1 for scavenging of small particles by large, fast-sinking ones to play a significant role in deposition from nepheloid layers. Assuming that one in every 10 fine particles that collide with a marine snow particle sticks to it, to achieve the above removal rate given a marine snow concentration of 10 -4 particles cm -3 requires contact efficiencies of 10 -1 to 10 -2 . Such values of contact efficiency are significantly larger than theoretical predictions of contact efficiency, but are supported by evidence from studies of radionuclide fluxes and particle size distributions. Discrepancies between inferred and predicted values of contact efficiency arise from differences in actual and model particle properties. Contact by direct interception potentially is enhanced by roughened particle surfaces and by wake capture. Wake capture is the process whereby fine particles are entrained in the recirculating eddies present behind settling particles with Reynolds numbers greater than one.
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