Water transport, migration characteristics

Fissure Elution Experiments. The migration characteristics of americium by water transport in fissures fabricated from gray hornblende schist were determined. Fissures not used in the previous sorption experiments were used for these elution experiments. A diagram of the experimental apparatus is shown in Figure 4. Solution reservoirs were attached above the fissures and the small bore tubes affixed to the bottom of the fissures were connected to solution metering pumps. 

Moving air can only transport sand and dust, and does not erode solid rock very effectively. Its characteristic landforms, sand dunes, occur in many sizes and shapes. Most have a gentle slope on the windward side, where sand is being eroded away, and a steeper leeward side, where sand is deposited. Movement of sand from one side to the other may result in the migration of the sand dnne in the direction the wind is blowing. As with water, transport capability varies with velocity, so sand dunes often develop where the wind slows down. This is the case at Great Sand Dunes National Monument, Colorado, and Death Valley National Park, California, where spectacular, but localized, dune fields occur. 

NAPL will migrate from the liquid phase into the vapor phase until the vapor pressure is reached for that liquid. NAPL will move from the liquid phase into the water phase until the solubility is reached. Also, NAPL will move from the gas phase into any water that is not saturated with respect to that NAPL. Because hydraulic conductivities can be so low under highly unsaturated conditions, the gas phase may move much more rapidly than either of the liquid phases, and NAPLs can be transported to wetter zones where the NAPL can then move from the gas phase to a previously uncontaminated water phase. To understand and model these multiphase systems, the characteristic behavior and the diffusion coefficients for each phase must be known for each sediment or type of porous media, leading to an incredible amount of information, much of which is at present lacking. 

Large amounts of VOCs are generated in industrialized areas and eventually are discharged into surface waters or transported by the atmosphere. Once in the environment, VOCs can be absorbed into biota and soil, and, depending on soil characteristics, they can eventually migrate to... 

Food deterioration can occur by means other than transport of gases into the food container or water into or out of the container. The loss of food characteristics in plastics packaging may also occur from direct interaction of the food with the polymer. The measurement of these types of transport is often termed organoleptic analysis because they may involve human taste tests. The tainting of food by transport of substances from the polymer into the food is termed migration. The loss of flavor constituents from the food into the polymer is termed scalping (32). Water content can affect these transport characteristics as well. 

The protons (H+) and hydroxyl (OH ) ions generated by electrolysis reactions (Eqs. 1.1 and 1.2) migrate toward the oppositely charged electrode. Acar et al. (1995) determined that, generally, H+ is about twice as mobile as OH , so the protons dominate the system and an acid front moves across the soil until it meets the hydroxyl front in a zone near the cathode, where the ions may recombine to generate water. Thus, the soil is divided into two zones with a sharp pH jump in between a high-pH zone close to the cathode and a low-pH zone on the anode side. The actual soil pH values will depend on the extent of transport of H+ and OH ions and the geochemical characteristics of the soil. 

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