Saturation media

We will concentrate on adsorption-desorption. The one-dimensional form for homogeneous saturated media of the advection-dispersion equation can then be written as... 

In partially saturated media, the diffusion coefficient also is a function of the volumetric water content, 9. Calvet (1984) showed that the variation in soil water content influences the apparent diffusion coefficient for organic contaminants in two ways by changing the ratio of gas diffusion of volatilizable pollutants to liquid diffusion, because the air-filled porosity is affected, and by modifying pollutant... 

In partially saturated media, the moisture content affects NAPL migration significantly. Abriola and Pinder (1985) suggested that the flux of a phase p (NAPL, water, or air), J, can be written as... 

For example, electroreduction of 61 in DMF/E NCIQ containing acetic acid as a proton source gives the hydrogenation product 62a (98-100%) while electroreduction of 61 in C02-saturated media affords carboxylic acid 62b (81-95%)39). Acetylation at the a/pfei-carbon atom is also achieved by the electroreduction of 61 in the presence of a 10-fold excess of acetic anhydride (30-70%)40). 

Chrysikopoulos and Kim [70] developed time invariant, local mass transfer correlations for NAPL pool dissolution in saturated media based on numerically determined local mass transfer coefficients evaluated for interstitial fluid velocities of 0.1,0.5,0.7,0.85, and 1.0 m/day. It should be noted that solubility concentrations may occur at a NAPL-water interface when interstitial fluid velocities are less than 1.0 m/day [8]. Over 200 different rectangular pools with dimensions xx y in the range from 0.2 mx0.2 m to 10.0 mxlO.O m and approximately the same number of elliptic/circular pools with semiaxes axb in the range 0.1 mxO.l m to 5.0 mx5.0 m were examined. 

Simunek J., Sejna M., and van Genuchten M. T. (1999) The HYDRUS-2D software package for simulating the two-dimensional movement of water, heat and multipe solutes in variably-saturated media—version 2.0. US Department of... 

Water flow in the vadose zone also is much more difficult to measure than is water flow in the saturated zone. Piezometers placed in unsaturated porous media do not fill with water, so head is less readily measured than it is in saturated media, and thus the direction and magnitude of the hydraulic gradient are more difficult to determine. For values of ifj between 0 and — 1 atm, tensiometers may be employed to directly measure pore water pressure. For very low values of i/j, other techniques may be used, such as the indirect assessment of if from measurements of the humidity of the air in the pore spaces. 

Simunek J, Huang K, van Genuchten MT. The HYDRUS code for simulating the one-dimensional movement of water, heat, and multiple solutes in variably-saturated media. Version 6.0, Research report 144, U.S. Salinity Laboratory, USDA, ARS, Riverside, CA, 1998. 

The frozen hydrate-saturated media formed during these experiments were used for a study of the CO2 hydrate decomposition kinetics in the pore space. The influence of soil mineral composition, ice content and temperature on the CO2 hydrate self-preservation effect was established. It is revealed, that a temperature decrease slows down the CO2 hydrate dissociation low negative temperatures (below -13 C) cause a complete stop of the CO2 hydrate dissociation process. It is also shown that ice forming in the remaining pore space from freezing of unreacted water enhances the CO2 hydrate self-preservation effect. 

Although anomalous diffusion is expected in fractal pore systems, the presence of anomalous diffusion does not prove that the porous media is fractal. A heterogeneity along transport pathways may result in an anomalous transport regardless of the presence or the absence of self-similarity of the pore space (Beven et al., 1993). The physical interpretation of Levy motions does not presume the presence of fractal scaling in the porous media in which the motions occur (Klafter et al, 1990). The applicability of the FADE may be closely related to the distribution of pore-water velocities. In saturated media, the presence of heavy-tailed distributions of the hydraulic conductivity directly implies the validity of the FADE (Meer-schaert et al., 1999 Benson et al., 1999). The heavy-tailed hydraulic conductivity distributions were found in geologic media (Painter, 1996 Benson et al., 1999). Heavy-tailed velocity distributions can also be expected in unsaturated and structured soils, and therefore the FADE may be a useful model in these conditions. 

Models Relating Solute Dispersion to Pore Space Geometry in Saturated Media A Review... 

The isotherms are incorporated into the transport models through the retardation factor R. The one-dimensional ADR equation for saturated media becomes... 

Geilikman, M.B., Spanos, T.J.T., and Nyland, E., 1993. Porosity diffusion in fluid-saturated media. Tectonophysics, 217, 11-113. 

ROCMAS is a finite-element code for analysis of coupled THM processes in partially saturated geological media (Noorishad and Tsang, 1996, Rutqvist et al., 2001). In ROCMAS, the Biot (1941) formulation is extended to partially saturated media through Philip and de Vries (1957) theory for heat- and moisture-flow in soil. This results in a comprehensive coupled THM formulation for partially saturated geological media that includes the coupled processes shown in Figure 2. 

Xu, T., Sonnenthal, E., Spycher, N., Pruess, K. 2003. TOUGHREACT A new code of the TOUGH family of non-isothermal multiphase reactive geochemical transport in variably saturated media. Proceedings, TOUGH Symposium, 2003. 

Porosity diffusion in fluid -saturated media. Tectonophysics, 217, 111-115. 

Evaluation of maximum swelling pressure in saturated media... 

Simunek, X Sejna, M. van Genuchten, M. Th. (1999) The HYDRUS-2D Software Package for Simulating the Two-Dimensional Movement of Water, Heat, and Multiple Solutes in Variably-Saturated Media, Version 2.0, U. S. Salinity Laboratory, USDA, ARS. 

For the standard systems, dyed PCE was added to the water-saturated media, untreated quartz sand and Rhodorsil-treated sand. In the other systems, DDA was added to die dyed PCE phase and then the organic mixture was added to the water-saturated hematite-coated and untreated quartz sands. All botdes were capped and then vigorously shaken by hand. 

PPy layers that forms the outside layers on either side of a polymer electrol5de layer in the middle. The pol5mier electrolyte layer could be solid state electrolyte or electrol5de saturated media (i.e., porous PVDF film). Once a voltage is applied, one PPy layer performs as cathode and the other performs as the anode. Since oxidation and reduction occur separately at both sides, expansion and contraction on each side will cause bending actuation (Fig 4.9). 

Figure 2 Schematic of residually saturated media shown at pore scale.

Sleep, B. E. and J. F Sykes. 1989. Modeling the transport of volatile organics in variably saturated media. Water Resources Research 25, 81-92. 

Imhoff, P.T., Jaffe, PR. and G.F. Pinder. 1993. An experimental study of complete dissolution of nonaqueous phase liquids in saturated media. Water Resources Research 30(2) 307-320. 

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