Sediments, compact

The substitution of Kollidon 30 by Kollidon 90F gives a more compact sediment. 

The deletion of citric acid gives a much more compact sediment. 

Berner, R.A. Diagenetic models of dissolved species in the interstitial waters of compacting sediments. Amer. Jour. Sci. 275, 88-96 (1975). 

In another vein, double layers play a role In the salt-sieving phenomenon, mentioned In the Introduction to Volume I, and already known to Aristotle. When seawater percolates over a compact sediment of slllcate-like particles, under some conditions the effluent Is potable. Basically the phenomenon is attributable to the negative adsorption of (in this case) anions, leading to the Donnan expulsion of electrolyte, see sec. 3.5b. Over-demand may lead to salt penetration the screening of the double layers around the silica particles (reduction of x ) makes the pores between them effectively wider. For this problem technical solutions had to be found. 

Imboden D. M. (1975) Interstitial transport of solutes in nonsteady state accumulating and compacting sediments. Earth Planet Set Lett 27, 221-228. 

Domenico, P.A. and V.V. Palciauskas, 1979. Thermal expansion of fluids and fracture initiation in compacting sediments Summary. Geological Society of America Bulletin, Part I, Vol. 90, pp. 518-520... 

Einsele, G., 1976. Rise of primary pore water (connate water) in compacting sediments. In Hydrogeology of Great Sedimentary Basins. Int. Hydrol. Conference, Budapest, 1976, pp. 134-135... 

Hooper, E.C.D., 1991. Fluid migration along growth faults in compacting sediments. Journal of Petroleum Geology, Vol. 14(2), pp.161-180... 

Sharp, Jr., J. and Domenico, P. 1976. Energy transport in thick sequences of compacting sediment. Geol. Soc. Am. Bull., 87 390-400. 

Such cements occur in weakly compacted sediments and are characterized by low 6 0 values and fluid inclusions with high homogenization temperatures. This mechanism imposes difficulties in recognizing these cements from those formed by recrystallization at increased temperatures, as both mechanisms preserve a high, pre-cement porosity. A few workers (Giroir et al., 1989 Souza et al., 1995) argued that the early emplacement of calcite cement in sandstones of rift basins may take place... 

Usnally, there are fonr zones in a thickener the clarification zone, the feed zone, the transition zone, and the compression zone. Not all of these zones will be present for all types of slurries. Liquid flows out of the feed zone, up through the clarification zone, and toward the overflow. Below the feed is the transition zone, where the particles start a downward motion. The concentration just below the supernatant-suspension (or sediment) interface assumes a value dictated by the dominance of either free settling or the presence of a compacting sediment. The region containing the particles offers resistance to liqnid flow and accepts only a portion of the liquid. The remainder reverses direction and exits as overflow. Under steady-state conditions, both solids and liquid fluxes are constant and independent of depth in the snspension and/or sediment zone. No liquid is squeezed out and upward in the sediment unless channels exist. 

Metallic americium has a face-centered cubic structure at its melting point and a double hexagonal closed-packed structure at temperatures below its melting point. The isotope americium-241 emits a-particles and y-rays in its radioactive decay, and is a source of y-radiation, used to measure the thickness of metals, coatings, degree of soil compaction, sediment concentration, and so on. The same isotope, mixed with beryllium, is used as a neutron source in oilwell logging and other applications. Americium-241... 

Fig. 15.11 Sediment-acoustic profile (PARASOUND) of the continental slope off die coast of Uruguay (Bleil and participants 1994). A sediment avalanche is recognizable below deposited as a compact sediment. The sediment core GeoB2809 also originated from diis profile, including die pore water profiles shown in Fig. 15.12. (see also Hensen et al. 2003).

Fig 2). This is shown by the more compact sediments. Alumina with an amphoteric surface was stabilized by dispersants and strongly acid or strongly basic solvents by a combined steric and electrostatic mechanism. Hexane, which is a nonpolar solvent with no hydrogen bonding capability, is shown to be a poor solvent for AHAS, which is a highly polar dispersant. Hexane would introduce a low potential as well hence the stability had to rely solely on the steric stabilization contribution. When the adsorbate AHAS is not highly soluble in the medium, the dispersant is ineffective as a steric stabilizer. Despite the high dielectric constant of EtOH, it is shown to be an ineffective medium with LNA. EtOH as a weakly acid solvent introduced nearly a zero potential... 

Banded coal contains visible bands of vitrain, which is the remains of single large fragments of ancient plants (see the earlier text), as well as bands of fusain, the remains of smaller fragments of ancient plants (see earlier text). Non-banded coal, however, displays a uniform texture which appears to be fine-grained, lacks a brilliant luster, and consists of comminuted, compacted sediments derived from plant detritus. This type of coal is much less common than banded coal in North America. There are two major types of non-banded coal cannel coal and boghead coal (Stach et al., 1982). 

Flocculating agents are added for creating an open and large volume sediment that can be resuspended easily they prevent caking the occurrence of a compact sediment on the bottom of the bottle (see Sect. 18.4.2). In suspensions with negatively charged particles, multivalent cations, such as aluminium ions, may cause flocculation. On positively... 

The combination of carmellose sodium with aluminium magnesium silicate is a common combination in oral suspensions. Carmellose enhances the viscosity and is easy to process. However, it cannot always avoid a compact sediment. Aluminium magnesium silicate creates an open sediment that is easy to disperse. It also has some viscosity enhancing properties. 

Both deflocculated and flocculated systems have advantages and disadvantages. In a deflocculated system sedimentation proceeds slowly but once it is completed, it is very difficult to disperse the very compact sediment The... 

Irregularly shaped particles and flocculates cause the development of a structure with its own yield stress level. As the particles move closer, the yield stress increases until equilibrium is reached. The weight of the overburden is then supported hy the saturated fluid and the compacted sediment. 

Palciauskas, V.V. Domenico, P.A. Microfracture development in compacting sediments relation to hydrocarbon-maturation kinetics. AAPG Bulletin 1980, 64, 927-937. 

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