Sedimentation, gravity controls

A series of gravity cores was collected inside the inlet and at a control station located some 5 km north of the inlet in Port Orchard Passage, as shown in figure 2. The sedimentation rates as determined by 210Pb are shown in figure 4a where a least squares fit of the data gives an average sedimentation rate of... 

Although the production of highly deflocculated suspensions is a primary objective for formulation of suspension concentrates, these systems tend to settle under gravity forming dilatant sediments (clays). The latter must be prevented either by controlled flocculation or by the addition of a second disperse phase to the continuous medium (1). One method which may be applied to sterlcally stabilised dispersions, is to add a free (ie. non-adsorbing) polymer to the continuous medium. 

The gravity settle plate, which provides passive measurement of microorganisms likely to deposit by sedimentation at critical and controlled sites within a given period, and... 

Three physical treatment devices employed in wastewater treatment control include screens, grit chambers, and gravity sedimentation. Briefly describe each of these devices. 

A patent was granted in 1969 for a gravity. X-ray, sedimentation design. A predispersed sample is introduced into a temperature controlled measurement cell. Observations are taken of the incremental change in concentration or density, with respect to time, of the sample at a specific point within the cell. These observations are made by either X-ray or light scattering extinction techniques (Figure 5). 

It is important to note that physical properties depend on various other factors controlling the behavioural pattern of the material. Clay sedimentation properties depend on porosity, water content and minerals content of different specific gravity. Electrical conductivity depends on porosity, saturation, pore fluid conductivity, water content, and clay content. Velocity is very sensitive to saturation (air-water) but hardly at all to fluid composition. On the other hand, conductivity is very sensitive to both saturation and pore fluid conductivity. If saturation is determined from velocity, the fluid type can be determined uniquely from conductivity. 

Figure 1. Schematic of the bio-contact oxidation system for air pollution control. (1) buffer poor (2) air floatation (3) bio-contact oxidation reactor 1 (4) bio-contact oxidation reactor 2 (5) gravity sedimentation (6) peristaltic pump (7) Air pump.

There are several commercial photosedimentation analyzers. Figure 34-8 shows a schematic diagram of one instrument (the Horiba CAPA-700) that can achieve sedimentation by gravity or by centrifugal force. The components consist of an optical system, a centrifuge, control circuitry, and a computation system. 

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